Materiały źródłowe

• #1 Bowel Ischemia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK554527/

  Bowel ischemia can classify as small intestine ischemia, which is commonly known as mesenteric ischemia and large intestine ischemia, which generally referred to as colonic ischemia. Intestinal ischemia occurs when at least a 75% reduction in intestinal blood flow for more than 12 hours. […] The intestine is mainly supplied by 2 major arteries, which include the superior mesenteric artery (SMA) and the inferior mesenteric artery (IMA). […] Two main areas in the colon, including splenic flexure (Griffiths point) and rectosigmoid junction (Sudek’s point), are prone to ischemia. These are also known as the 'watershed’ areas, which mean the regions in the colon between 2 major arteries that supplying colon. […] An acute decrease in mesenteric arterial blood flow accounts for 60% to 70% of patients with mesenteric ischemia.

• #1 Intestinal ischemia – Wikipedia

  https://en.wikipedia.org/wiki/Intestinal_ischemia

  Intestinal ischemia is a medical condition in which injury to the large or small intestine occurs due to not enough blood supply. […] There are four mechanisms by which poor blood flow occurs: a blood clot from elsewhere getting lodged in an artery, a new blood clot forming in an artery, a blood clot forming in the superior mesenteric vein, and insufficient blood flow due to low blood pressure or spasms of arteries. […] Treatment of acute ischemia may include stenting or medications to break down the clot provided at the site of obstruction by interventional radiology. […] Surgical revascularisation remains the treatment of choice for intestinal ischaemia related to an occlusion of the vessels supplying the bowel, but thrombolytic medical treatment and vascular interventional radiological techniques have a growing role. […] The prognosis depends on prompt diagnosis (less than 12-24 hours and before gangrene) and the underlying cause.

• #1

  https://step1.medbullets.com/gastrointestinal/109050/mesenteric-ischemia

  can be due to a variety of processes […] acute mesenteric ischemia is most commonly caused by an embolism in the main mesenteric artery […] chronic mesenteric ischemia is most commonly caused by atherosclerosis […] embolism secondary to atrial fibrillation, myocardial infarction, or valvular disease […] thrombosis secondary to artherosclerosis […] splanchnic vasoconstriction […] hypoperfusion due to hypotension […] venous thrombosis.

• #1 Biochemical markers of acute intestinal ischemia: possibilities and limitations

  https://atm.amegroups.org/article/view/20595/20750

  Acute intestinal ischemia is a relative rare abdominal emergency, associated with considerably high morbidity and mortality rates. […] The pathophysiology is complex and multifaceted. The intestinal acute vascular insufficiency leads to renin-angiotensin activation, sympathic stimulation, vasospasm and consequently hypoxia. […] The persistence of ischemia may then lead to an evolvement of transmural infarction towards irreversible injury and necrosis, intestinal perforation and release of bacteria and toxins into the systemic circulation. […] Despite ample research in this field, early, sensitive and specific biomarkers of acute intestinal ischemia have not been identified so far. […] The aim of this narrative review is hence to provide an overview on traditional laboratory biomarkers of acute intestinal ischemia and summarize current evidence regarding some emerging and potentially useful biomarkers.

• #1 Intestinal Ischemia & Angiodysplasia – Free Sketchy Medical Lesson

  https://www.sketchy.com/medical-lessons/intestinal-ischemia-angiodysplasia

  Ischemia initially affects the small vessels near the luminal surface of the villi in the bowel, leading to their sloughing. This triggers edema in the bowel wall, which increases pressure and obstructs venous drainage, exacerbating the ischemia. Initially, the crypts of the bowel are spared, but become involved as ischemia progresses. The end result is intestinal necrosis, patchy mucosal hemorrhage, and a neutrophilic infiltrate as a response to inflammation.

• #1 Mesenteric ischemia pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Mesenteric_ischemia_pathophysiology

  Immune cells remove dead and damaged cells releasing cytokines such as TNF-alpha. […] Blood vessels become more permeable leading to edema of the small intestine. […] As the ischemia progresses from mucosa to all the layers beneath (transmural), it leads to breaks in the epithelial lining. […] This allows bacteria in the intestinal lumen to enter into the peritoneal cavity causing peritonitis. […] If bacteria enter into the blood stream, it results in systemic inflammatory response syndrome, which ultimately results in sepsis and septic shock.

• #1 Intestinal ischemia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/intestinal-ischemia/symptoms-causes/syc-20373946

  Intestinal ischemia often is split into groups. Colon ischemia, also called ischemic colitis, affects the large intestine. Other types of ischemia affect the small intestine. These are acute mesenteric ischemia, chronic mesenteric ischemia and ischemia due to mesenteric venous thrombosis. […] Acute mesenteric ischemia is the result of a sudden loss of blood flow to the small intestine. It may be due to: A blood clot, also called an embolus, that comes loose in the heart and travels through the blood to block an artery. It most often blocks the superior mesenteric artery, which sends oxygen-rich blood to the intestines. […] Chronic mesenteric ischemia is due to the buildup of fatty deposits on an artery wall, called atherosclerosis. The disease process most often is slow. It’s also called intestinal angina because it’s due to less blood flow to the intestines after eating.

• #1 Acute mesenteric ischemia: updated guidelines of the World Society of Emergency Surgery | World Journal of Emergency Surgery | Full Text

  https://wjes.biomedcentral.com/articles/10.1186/s13017-022-00443-x

  NOMI occurs in approximately 20% of cases, and is usually a consequence of SMA vasoconstriction associated with low splanchnic blood flow. The compromised SMA blood flow also affects the proximal colon due to involvement of the ileocolic artery. Patients with NOMI typically suffer from severe coexisting illness, commonly cardiac failure which may be precipitated by sepsis. […] Mesenteric venous thrombosis (MVT) accounts for less than 10% of cases of mesenteric infarction. Thrombosis is attributed to a combination of Virchow’s triad; stagnant blood flow, hypercoagulability, and endothelial damage. An inflammatory process around the superior mesenteric vein (SMV) due to acute pancreatitis or inflammatory bowel disease may cause thrombosis. […] The prevalence of AMI has changed in recent decades. The prevalence of acute mesenteric occlusion among patients with an acute abdomen may vary from 17.7% in emergency laparotomy and 31.0% in laparotomy for elderly non-trauma patients. Mesenteric arterial embolism decreased to 25% of cases. Mesenteric arterial thrombosis was the second most common cause of mesenteric ischemia, which historically accounted for 20-35% and recently increased to 40%. NOMI accounts for 25% of cases, which is also increasing, compared to the historical cohort, because of increased number of critically ill patients and overall improvement of intensive care.

• #1 Acute Mesenteric Ischemia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK431068/

  An acute mesenteric arterial embolism is often cardiogenic in origin and primarily affects the superior mesenteric artery (SMA). Preceding events include atrial tachyarrhythmia, congestive heart failure, myocardial ischemia or infarction, cardiomyopathy, and ventricular aneurysm, which results in thrombus formation that later embolizes to cause ischemia. […] Patients with acute mesenteric arterial thrombosis commonly have a pre-existing atherosclerotic disease. Vasospasm in the SMA often accompanies NOMI secondary to cardiac failure, peripheral hypoxemia, or reperfusion injury. […] In rare instances, vasopressors (e.g., cocaine and norepinephrine) and ergotamines may cause NOMI. These agents cause vasoconstriction and reduced blood flow in the mesentery, which may result in ischemia of the bowel.

• #1 Intestinal Ischemia & Angiodysplasia – Free Sketchy Medical Lesson

  https://www.sketchy.com/medical-lessons/intestinal-ischemia-angiodysplasia

  Non-occlusive acute mesenteric ischemia usually occurs in the colon and is caused by hypoperfusion of intestinal vessels, which can occur in cases of hypovolemia, septic shock, and cardiogenic shock. […] Chronic mesenteric ischemia occurs secondary to generalized atherosclerotic disease and manifests as intestinal angina with postprandial abdominal pain, aversion to eating, and weight loss. […] Intestinal ischemia occurs due to inadequate perfusion of the bowel due to occlusive and non-occlusive etiologies. The primary occlusive cause is acute mesenteric artery occlusion, most commonly seen in the superior mesenteric artery (SMA) and often from an embolus or a thrombus formed from ruptured atherosclerotic plaques. Non-occlusive acute mesenteric ischemia occurs due to hypoperfusion of intestinal vessels.

• #1 Intestinal ischemia – Knowledge @ AMBOSS

  https://www.amboss.com/us/knowledge/intestinal-ischemia/

  Sudden interruption of blood flow to small bowel; intestinal hypoxia hemorrhagic infarction and necrosis disruption of the mucosal barrier and perforation release of bacteria, toxins, and vasoactive substances life-threatening sepsis. […] Thrombus formation in addition to stenosis can lead to acute-on-chronic mesenteric ischemia, which leads to AMI.

• #1 Bowel Ischemia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK554527/

  Intestinal ischemia occurs when at least a 75% reduction in intestinal blood flow for more than 12 hours. […] Generally, mesenteric ischemia (MI) can be divided based on the timing of onset into acute and chronic. […] Collateral circulation of the gastrointestinal tract can compensate for a 75% acute reduction in mesenteric perfusion for up to 12 hours without significant injury. […] The splanchnic circulation varies based on the feeding or fasting state. Despite high intestinal vasculature, oxygen extraction is low from the intestinal arteries. […] Intestinal ischemia happens when inadequate oxygen delivered to the intestine. However, intestinal injury occurs by low perfusion and reperfusion of intestinal tissues. […] Low perfusion can cause intestinal injury when mesenteric perfusion pressure decreases about 30 mmHg or reduction of 45 mmHg in mean mesenteric arterial pressure.

• #1 Many faces of acute bowel ischemia: overview of radiologic staging | Insights into Imaging | Full Text

  https://insightsimaging.springeropen.com/articles/10.1186/s13244-021-00985-9

  Acute bowel ischemia (ABI) can be life threatening with high mortality rate. […] ABI is potentially reversible with prompt diagnosis. […] While ABI has been traditionally categorized based on the etiology with a wide spectrum of imaging findings overlapped with each other, the final decision for patients management is usually made on the stage of the ABI with respect to the underlying pathophysiology. […] Understanding the pathologic basis of ABI can help to estimate the probability of reversibility and choose the optimal treatment option. […] ABI is categorized into 3 stages based on the involvement of each layer. […] The early stage of ischemia is typically followed by the release of certain mediators (cytokines, platelet-activating factor and tumor necrosis factor), which leads to an inflammatory response, resulting in further damage of the intestinal wall.

• #1 Many faces of acute bowel ischemia: overview of radiologic staging | Insights into Imaging | Full Text

  https://insightsimaging.springeropen.com/articles/10.1186/s13244-021-00985-9

  Stage II or the intermediate stage is described as presence of specific pathologic changes (edema, erosion, hemorrhage and necrosis) in submucosa and muscularis propria. […] Stage III, the late stage, is manifested by transmural bowel necrosis and is developed if blood supply is not eventually restored. […] It should be noted that bowel ischemia accompanied by reperfusion injury may lead to the disruption of mucosal barrier followed by bacterial invasion, septic shock and multiorgan failure, which may cause death without transmural necrosis. […] Understanding the pathophysiology of ABI can help for better management. […] Management should be based on the latest stage identified. […] The main goal of management is to achieve a prompt diagnosis, specify the best treatment option and reduce mortality in these patients.

• #1 Bowel Ischemia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK554527/

  However, after a prolongation of low perfusion or hypoxemia, progressive vasoconstriction leads to reducing collateral flow and subsequently full-thickness necrosis of the intestinal wall and perforation. […] Reperfusion injury after ischemia can be observed due to the release of toxic byproducts of ischemic injury, free oxygen radicals, and neutrophil activation.

• #1 Intestinal Ischemia and Reperfusion: Consequences and Mechanisms | SpringerLink

  https://link.springer.com/10.1007/978-3-642-37078-6_240

  Ischemia and reperfusion of the ischemic intestine can result in significant tissue injury that is manifested as vascular dysfunction and mucosal barrier failure. […] The injury response to ischemia per se can be attributed to hypoxia and the cellular alterations brought about by this condition. […] Reperfusion of the ischemic intestine is accompanied by a more profound injury response that has been linked to the generation of reactive oxygen species that are derived from the enzyme xanthine oxidase. […] The accumulation of these reactive species at the time of reperfusion, coupled with the inactivation of nitric oxide, creates an inflammatory phenotype within the vasculature and mucosal membrane. […] The resulting recruitment of leukocytes and platelets and the activation of resident inflammatory cells that normally reside in the perivascular space (mast cells, macrophages) lead to further oxidative stress and a more intense inflammatory condition, ultimately resulting in capillary and mucosal membrane failure and organ dysfunction.

• #1 Targeting cell death pathways in intestinal ischemia-reperfusion injury: a comprehensive review | Cell Death Discovery

  https://www.nature.com/articles/s41420-024-01891-x

  The main factors contributing to ferroptosis in intestinal I/R injury include oxidative stress, the release of iron ions, lipid peroxidation, and iron dependence. […] Intestinal I/R injury induces oxidative stress, characterized by the excessive accumulation of reactive oxygen species generated intracellularly. […] Autophagy may be induced during intestinal I/R to eliminate impaired cellular constituents and maintain cell viability. […] Autophagy flux was found to be impaired throughout the intestinal I/R procedure. […] The findings of the above-mentioned studies indicated that the assembly and activation of the NLRP3 inflammasome strongly influence the initiation of pyroptosis, irrespective of alterations in the target genes or pathways governing pyroptosis.

• #1 Intestinal Ischemia | Abdominal Key

  https://abdominalkey.com/intestinal-ischemia/

  The sympathetic nervous system, mainly via -adrenergic receptors, is of primary importance in maintaining resting splanchnic arteriolar tone; other vasoactive substances, including angiotensin II, vasopressin, and prostaglandins, also have been implicated in the pathogenesis of ischemic injury. […] Ischemic damage results both from hypoxia during the period of ischemia and reperfusion injury when blood flow is re-established. […] A potent source of oxygen radicals in ischemic, reperfused tissue is the enzyme xanthine oxidase (XO), the rate-limiting enzyme in nucleic acid degradation. […] Neutrophils are another source of reactive oxygen metabolites. […] The cornerstones of our approach, therefore, are the earlier and more liberal use of angiography and the incorporation of intra-arterial papaverine in the treatment of both occlusive AMI and NOMI. […] Diagnosis before intestinal infarction occurs is the most important factor in improving survival of patients with AMI.

• #1 SciELO Brazil – Pathophysiology of mesenteric ischemia/reperfusion: a review Pathophysiology of mesenteric ischemia/reperfusion: a review

  https://www.scielo.br/j/acb/a/nsvfz8j9KBgNvs5GKQ7CznN/

  The superoxide ions react with nitric oxide (NO) to produce peroxynitrite, which then causes accentuated lipid peroxidation, proteic and DNA modifications resulting in cellular damage. […] The activation of the complement system can lead to the translocation of NF-kB and an increase in the transcription of iNOS. […] The activation of neutrophils was also complement-dependent during intestinal I/R. […] The depletion or inhibition of the complement could diminish many of the mediators of I/R injury. […] The accumulation of platelets in the postischemic microvasculature could contribute significantly to the manifestation of I/R lesions. […] Serotonin together with other bioactive substances could perform an important function in the pathogenesis of intestinal I/R. […] It has been demonstrated recently that pancreatic proteases are involved in the production of inflammatory mediators after intestinal I/R.

• #1 Targeting cell death pathways in intestinal ischemia-reperfusion injury: a comprehensive review | Cell Death Discovery

  https://www.nature.com/articles/s41420-024-01891-x

  Intestinal ischemia-reperfusion (I/R) is a multifaceted pathological process, and there is a lack of clear treatment for intestinal I/R injury. During intestinal I/R, oxidative stress and inflammation triggered by cells can trigger a variety of cell death mechanisms, including apoptosis, autophagy, pyroptosis, ferroptosis, and necrosis. […] The mechanisms underlying cell death related to intestinal I/R injury can be categorized primarily into programmed and non-programmed forms. Programmed cell death includes apoptosis, autophagy, pyroptosis, and ferroptosis, whereas non-programmed cell death primarily refers to necrosis. […] In individuals with intestinal ischemia, affected cells experience inadequate oxygen and nutrient supplies, leading to energy metabolism disturbances and an unstable intracellular milieu. These changes promote programmed cell death.

• #1 Targeting cell death pathways in intestinal ischemia-reperfusion injury: a comprehensive review | Cell Death Discovery

  https://www.nature.com/articles/s41420-024-01891-x

  During post-ischemic reperfusion, stimulation and damage to the intestine increase, primarily due to the buildup of metabolites generated during ischemia and the release of oxygen free radicals. Under such conditions, the gut undergoes non-programmed cell death. […] The activation of multiple signaling pathways leads to the initiation of various mechanisms of cell death. […] Intestinal I/R injury induces apoptosis and necrosis in the intestinal epithelial cells, which results in impaired intestinal barrier function and ultimately leads to multiple organ dysfunction syndrome. […] The inflammatory response drives the occurrence of apoptosis and necrosis. […] The occurrence of pyroptosis in intestinal I/R injury was confirmed by histopathological findings and intestinal barrier indices, including transepithelial electrical resistance (TER), tight-junction protein, and serum biomarkers.

• #1 Ischemic Colitis: Symptoms & Treatment

  https://my.clevelandclinic.org/health/diseases/24513-ischemic-colitis

  Ischemic colitis is inflammation in your colon thats caused by ischemia, which means reduced blood flow. Blood supplies oxygen to the tissues in your body. If something interrupts or diminishes the blood supply to certain tissues, they suffer damage from the lack of oxygen. Inflammation is your bodys response to this injury. It causes discomfort, swelling and bleeding, but it means your tissues are trying to repair themselves. Ischemic colitis mainly affects the inner lining of your colon (mucosa), usually in one section of it. But ischemia thats more severe or lasts longer may do deeper damage to your colon. […] Reduced blood flow in the arteries that supply blood to your colon causes inflammation in the tissues as a secondary effect. […] The arteries that supply your colon your superior and inferior mesenteric arteries are extra sensitive to anything that causes your blood vessels to constrict (vasoconstriction). This includes physical triggers like colds, medical conditions that cause low blood pressure and certain drugs (vasoconstrictors). These arteries respond to low blood pressure by constricting vigorously. Scientists believe this may be a survival mechanism designed to direct reduced blood flow to your more vital organs, like your brain and heart. As a result, your colon may be deprived of blood flow while this stress response is activated.

• #1 Mesenteric ischemia pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Mesenteric_ischemia_pathophysiology

  The factors that regulate the intestinal blood flow play a vital role in the development of mesenteric ischemia. […] Mesenteric ischemia occurs when intestinal blood supply is compromised by more than 50% of the original blood flow without activation of adaptive responses. This can lead to disruption of mucosal barrier, allowing the release of bacterial toxins (present in the intestinal lumen) and vasoactive mediators which ultimately lead to complete necrosis (cell death) of the intestinal mucosa. […] Intestinal mucosal damage occurs in response to ischemic insult. […] In response to providing protection from ischemia, mesenteric vessels undergo intrinsic autoregulation, which is an adaptive response to ischemia. […] In order to compensate for the ischemia, there is vasoconstriction of mesenteric vessels resulting in increased tissue oxygen extraction along with vasodilation of the collateral vessels. Owing to this mechanism, intestine is able to compensate for around 75% reduction in blood flow.

• #1 Delayed Diagnosis of Mesenteric Ischemia | PSNet

  https://psnet.ahrq.gov/web-mm/delayed-diagnosis-mesenteric-ischemia

  The frequency of these major causes of mesenteric ischemia among all patients is estimated as: 50% mesenteric arterial embolism, 15-25% mesenteric arterial thrombosis, 5% mesenteric venous thrombosis, and 20-30% nonocclusive mesenteric ischemia. […] Risk factors for developing mesenteric ischemia vary by etiology but include any process that results in mesenteric hypoperfusion or increases the likelihood of intestinal embolism, thrombosis, or vasoconstriction. […] Given the potential for devastating outcomes when not diagnosed in a timely fashion, as in the presented case, mesenteric ischemia is an important diagnosis to consider in all patients with severe abdominal pain. […] Symptoms of weight loss and dietary changes in the setting of atherosclerosis should increase suspicion for chronic mesenteric ischemia until proven otherwise.

• #1 Acute mesenteric ischemia: updated guidelines of the World Society of Emergency Surgery | World Journal of Emergency Surgery | Full Text

  https://wjes.biomedcentral.com/articles/10.1186/s13017-022-00443-x

  The incidence of AMI increases exponentially with age. In patients aged 75 years or older, AMI is a more prevalent cause of acute abdomen than appendicitis. The incidence of AMI in an 80-year-old is roughly tenfold that of a 60-year-old patient. […] AMI has been described in patients with coronavirus disease (COVID-19), probably related to large vessel thromboembolic events as well as to small vessel thrombosis linked to hypercoagulability and fibrinolysis shutdown. […] The key to early diagnosis is a high level of clinical suspicion. The clinical scenario of a patient complaining of excruciating abdominal pain with an unrevealing abdominal examination is classic for early AMI. The reason for the pain being disproportionate to the clinical findings is that ischemia starts from the mucosa toward the serosa.

• #1 Intestinal ischemia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/intestinal-ischemia/symptoms-causes/syc-20373946

  Intestinal ischemia (is-KEE-me-uh) refers to a range of conditions that happen when blood flow to the intestines slows or stops. Ischemia can be due to a fully or partly blocked blood vessel, most often an artery. Or low blood pressure may lead to less blood flow. Intestinal ischemia can affect the small intestine, the large intestine or both. […] Less blood flow means that too little oxygen goes to the cells in the system through which food travels, called the digestive system. Intestinal ischemia is a serious condition that can cause pain. It can make it hard for the intestines to work well. […] In severe cases, loss of blood flow to the intestines can cause lifelong damage to the intestines. And it may lead to death. […] Intestinal ischemia happens when the blood flow through the major blood vessels that send blood to and from the intestines slows or stops. The condition has many possible causes.

• #1 Acute Mesenteric Ischemia – Gastrointestinal Disorders – Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/gastrointestinal-disorders/acute-abdomen-and-surgical-gastroenterology/acute-mesenteric-ischemia

  The intestinal mucosa has a high metabolic rate and, accordingly, a high blood flow requirement (normally receiving 20 to 25% of cardiac output), making it very sensitive to the effects of decreased perfusion. Ischemia disrupts the mucosal barrier, allowing release of bacteria, toxins, and vasoactive mediators, which in turn leads to myocardial depression, systemic inflammatory response syndrome, multisystem organ failure, and death. Mediator release may occur even before complete infarction. […] Mesenteric blood flow may be disrupted on either the venous or arterial sides. […] Early diagnosis of mesenteric ischemia is particularly important because mortality increases significantly once intestinal infarction has occurred. […] If diagnosis and treatment take place before infarction occurs, mortality is low; after intestinal infarction, mortality is high and varies depending on the etiology.

• #1 Small Bowel Ischemia – American College of Gastroenterology

  https://gi.org/topics/small-bowel-ischemia/

  The goals of treatment are to restore blood supply to the intestines and maintain proper function in the digestive tract. Treatment options for intestinal ischemia vary depending on the cause of the condition and the severity of damage in the intestines. […] If you have small bowel ischemia but no damage to intestinal tissue, medications may be enough to manage the condition. Your doctor may recommend one or more medications, such as: Clot-busting medications to break up blood clots. […] Depending on your specific case, surgery might be the best treatment option. Typical surgical procedures include: Laparoscopy: The surgeon makes a few tiny incisions and uses small instruments to restore blood flow to the small bowel. […] Small bowel ischemia can lead to complications such as: Rupture: A hole in the intestinal wall can form, causing the contents of the intestine to leak into the abdominal cavity.

• #1 SciELO Brazil – Pathophysiology of mesenteric ischemia/reperfusion: a review Pathophysiology of mesenteric ischemia/reperfusion: a review

  https://www.scielo.br/j/acb/a/nsvfz8j9KBgNvs5GKQ7CznN/

  More recent studies indicate that apoptosis is clearly a significant and, perhaps, the principal contributor to cellular death after I/R injury. […] Apoptosis inhibitors in injured tissue can preserve functional and morphological integrity in organs submitted to I/R. […] Reactive chemical species initiate a sequence of events including the activation of neutrophils and the release of harmful substances like PAF and histamine. […] Multiple organ failure is a frequent complication after intestinal I/R and involves organs like the liver, heart, kidneys and lungs. […] The events which occur during I/R are complex and well studied, although, there still remain many doubts as to their pathophysiology and therapeutics, revealing the need for new research to obtain a more complete understanding and in the search for improved treatments.

• #1 Biochemical markers of acute intestinal ischemia: possibilities and limitations

  https://atm.amegroups.org/article/view/20595/html

  Acute intestinal ischemia is a relative rare abdominal emergency, associated with considerably high morbidity and mortality rates. […] The pathophysiology is complex and multifaceted. The intestinal acute vascular insufficiency leads to renin-angiotensin activation, sympathic stimulation, vasospasm and consequently hypoxia. […] The persistence of ischemia may then lead to an evolvement of transmural infarction towards irreversible injury and necrosis, intestinal perforation and release of bacteria and toxins into the systemic circulation. […] Despite ample research in this field, early, sensitive and specific biomarkers of acute intestinal ischemia have not been identified so far. […] The aim of this narrative review is hence to provide an overview on traditional laboratory biomarkers of acute intestinal ischemia and summarize current evidence regarding some emerging and potentially useful biomarkers.

• #1 Biochemical markers of acute intestinal ischemia: possibilities and limitations

  https://atm.amegroups.org/article/view/20595/html

  D-lactate is normally produced at very low concentrations in humans. […] An alteration of mucosal integrity due to intestinal ischemia may be a reasonable cause of increased D-lactate concentration in blood. […] Although D-lactate seems hence to perform better than L-lactate because of its exclusively intestinal source, the results obtained in different studies are mostly inconsistent. […] IMA is a biologic marker that can be easily and inexpensively measured in clinical laboratories. […] The first preliminary investigation in patients with intestinal ischemia was published in 2008, and showed that IMA values were significantly higher in seven patients with acute mesenteric ischemia compared to seven healthy subjects. […] Notably, the peculiar IMA kinetics is characterized by an early increase in parallel with the onset of ischemia, with values then further increase for hours afterwards.

• #1 Biochemical markers of acute intestinal ischemia: possibilities and limitations

  https://atm.amegroups.org/article/view/20595/html

  -GST is another biomarker of oxidative stress potentially useful for diagnosing intestinal ischemia. […] Additional inflammatory biomarkers, such as C-reactive protein (CRP) or interleukin-6 (IL-6), have been investigated in intestinal ischemia diagnostics. […] Procalcitonin (PCT) may be seen as a valuable aid for diagnosing or monitoring intestinal ischemia. […] D-dimer was shown to display good diagnostic performance in thrombo-embolic occlusion of the superior mesenteric artery, but its diagnostic efficiency seems overall less satisfactory in nonvascular acute intestinal ischemia. […] Citrulline is a non-proteinogenic amino acid synthesized from glutamine by the small bowel enterocytes and is a precursor for de novo synthesis of arginine. […] A progressively decreasing intestinal perfusion and a loss of integrity of the enterocyte cell membrane both contribute the rapid release of I-FABP into circulation and further elimination by the kidneys. […] Although acute intestinal ischemia remains a relative rare condition, a timely and accurate diagnosis is needed to prevent the development of serious complications, up to death.

• #1 Acute mesenteric ischemia: guidelines of the World Society of Emergency Surgery | World Journal of Emergency Surgery | Full Text

  https://wjes.biomedcentral.com/articles/10.1186/s13017-017-0150-5

  Acute mesenteric ischemia (AMI) may be defined as a sudden interruption of the blood supply to a segment of the small intestine, leading to ischemia, cellular damage, intestinal necrosis, and eventually patient death if untreated. […] The overall incidence is low (0.09 to 0.2% of all acute admissions to emergency departments), representing an uncommon cause of abdominal pain. […] Prompt diagnostic and intervention are essential to reduce the high mortality rates (50 to 80%). […] Roughly, 50% of all cases of AMI are due to acute mesenteric embolism. […] Thrombosis of the SMA (approximately 25% of cases) is usually associated with pre-existing chronic atherosclerotic disease leading to stenosis. […] NOMI occurs in approximately 20% of cases and is usually a consequence of SMA vasoconstriction associated with low splanchnic blood flow.

• #2 Intestinal ischemia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/intestinal-ischemia/symptoms-causes/syc-20373946

  Intestinal ischemia (is-KEE-me-uh) refers to a range of conditions that happen when blood flow to the intestines slows or stops. Ischemia can be due to a fully or partly blocked blood vessel, most often an artery. Or low blood pressure may lead to less blood flow. Intestinal ischemia can affect the small intestine, the large intestine or both. […] Less blood flow means that too little oxygen goes to the cells in the system through which food travels, called the digestive system. Intestinal ischemia is a serious condition that can cause pain. It can make it hard for the intestines to work well. […] In severe cases, loss of blood flow to the intestines can cause lifelong damage to the intestines. And it may lead to death. […] Intestinal ischemia happens when the blood flow through the major blood vessels that send blood to and from the intestines slows or stops. The condition has many possible causes.

• #2 Intestinal ischemia – Knowledge @ AMBOSS

  https://www.amboss.com/us/knowledge/intestinal-ischemia/

  Intestinal ischemia occurs if bowel perfusion cannot meet the metabolic demands of the intestine. This relative hypoperfusion may be the result of atherosclerosis, thromboembolic disease, or severe systemic hypotension. […] Intestinal blood flow of the superior mesenteric artery (SMA) and/or inferior mesenteric artery (IMA) is acutely compromised intestinal hypoxia intestinal wall damage mucosal inflammation and possibly bleeding possible progression to infarction and necrosis (gangrenous colon ischemia) disruption of the mucosal barrier and perforation release of bacteria, toxins, and vasoactive substances life-threatening sepsis. […] Tissue damage depends on the severity and duration of perfusion disruption. […] Injury to the intestinal mucosa can occur after just 20 minutes of ischemia; transmural infarction and gangrene occur after 816 hours of ischemia.

• #2

  https://step1.medbullets.com/gastrointestinal/109050/mesenteric-ischemia

  can be due to a variety of processes […] acute mesenteric ischemia is most commonly caused by an embolism in the main mesenteric artery […] chronic mesenteric ischemia is most commonly caused by atherosclerosis […] embolism secondary to atrial fibrillation, myocardial infarction, or valvular disease […] thrombosis secondary to artherosclerosis […] splanchnic vasoconstriction […] hypoperfusion due to hypotension […] venous thrombosis.

• #2 Delayed Diagnosis of Mesenteric Ischemia | PSNet

  https://psnet.ahrq.gov/web-mm/delayed-diagnosis-mesenteric-ischemia

  Mesenteric ischemia occurs when there is reduced blood flow to the small or large intestines from multiple potential etiologies involving interruptions of either the arterial or venous systems. […] Acute mesenteric, or intestinal, ischemia occurs when perfusion abruptly decreases, with or without vascular occlusion. In general, the intestines are protected by an extensive collateral vasculature; as such, an ischemic insult develops when there is inadequate flow through either direct or collateral vessels. […] A sudden occlusive arterial obstruction is often due to thromboembolism frequently from a cardiac source that blocks the superior mesenteric artery (SMA), but it can also occur from thrombosis of an atherosclerotic plaque of the SMA. Nonocclusive mesenteric ischemia is the result of a low flow state often due to vasoconstriction in the setting of hypovolemia, vasopressor use, or poor cardiac output.

• #2 Delayed Diagnosis of Mesenteric Ischemia | PSNet

  https://psnet.ahrq.gov/web-mm/delayed-diagnosis-mesenteric-ischemia

  The frequency of these major causes of mesenteric ischemia among all patients is estimated as: 50% mesenteric arterial embolism, 15-25% mesenteric arterial thrombosis, 5% mesenteric venous thrombosis, and 20-30% nonocclusive mesenteric ischemia. […] Risk factors for developing mesenteric ischemia vary by etiology but include any process that results in mesenteric hypoperfusion or increases the likelihood of intestinal embolism, thrombosis, or vasoconstriction. […] Given the potential for devastating outcomes when not diagnosed in a timely fashion, as in the presented case, mesenteric ischemia is an important diagnosis to consider in all patients with severe abdominal pain. […] Symptoms of weight loss and dietary changes in the setting of atherosclerosis should increase suspicion for chronic mesenteric ischemia until proven otherwise.

• #2 Biochemical markers of acute intestinal ischemia: possibilities and limitations

  https://atm.amegroups.org/article/view/20595/html

  Acute intestinal ischemia is a relative rare abdominal emergency, associated with considerably high morbidity and mortality rates. […] The pathophysiology is complex and multifaceted. The intestinal acute vascular insufficiency leads to renin-angiotensin activation, sympathic stimulation, vasospasm and consequently hypoxia. […] The persistence of ischemia may then lead to an evolvement of transmural infarction towards irreversible injury and necrosis, intestinal perforation and release of bacteria and toxins into the systemic circulation. […] Despite ample research in this field, early, sensitive and specific biomarkers of acute intestinal ischemia have not been identified so far. […] The aim of this narrative review is hence to provide an overview on traditional laboratory biomarkers of acute intestinal ischemia and summarize current evidence regarding some emerging and potentially useful biomarkers.

• #2 Acute mesenteric ischaemia: a pictorial review | Insights into Imaging | Full Text

  https://insightsimaging.springeropen.com/articles/10.1007/s13244-018-0641-2

  Intestinal ischaemia refers to insufficient blood flow within the mesenteric circulation to meet the metabolic demands in the bowel. […] The initial ischaemic damage to the intestinal wall may then range from only mild and superficial necrosis limited to the mucosa (stage I), or damage extending to the submucosal and muscularis propria layers (stage II), to dangerous and life-threatening continuous necrosis of all bowel wall layers (transmural bowel infarction) (stage III). […] From the pathophysiological point of view, the initial purely ischaemic lesions of the intestine are typically followed by the release of certain mediators such as cytokines, platelet-activating factor and tumour necrosis factor, which will lead to an inflammatory response and additionally damage the bowel wall.

• #2 Bowel Ischemia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK554527/

  Bowel ischemia can classify as small intestine ischemia, which is commonly known as mesenteric ischemia and large intestine ischemia, which generally referred to as colonic ischemia. Intestinal ischemia occurs when at least a 75% reduction in intestinal blood flow for more than 12 hours. […] The intestine is mainly supplied by 2 major arteries, which include the superior mesenteric artery (SMA) and the inferior mesenteric artery (IMA). […] Two main areas in the colon, including splenic flexure (Griffiths point) and rectosigmoid junction (Sudek’s point), are prone to ischemia. These are also known as the 'watershed’ areas, which mean the regions in the colon between 2 major arteries that supplying colon. […] An acute decrease in mesenteric arterial blood flow accounts for 60% to 70% of patients with mesenteric ischemia.

• #2 Acute Mesenteric Ischemia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK431068/

  An acute mesenteric arterial embolism is often cardiogenic in origin and primarily affects the superior mesenteric artery (SMA). Preceding events include atrial tachyarrhythmia, congestive heart failure, myocardial ischemia or infarction, cardiomyopathy, and ventricular aneurysm, which results in thrombus formation that later embolizes to cause ischemia. […] Patients with acute mesenteric arterial thrombosis commonly have a pre-existing atherosclerotic disease. Vasospasm in the SMA often accompanies NOMI secondary to cardiac failure, peripheral hypoxemia, or reperfusion injury. […] In rare instances, vasopressors (e.g., cocaine and norepinephrine) and ergotamines may cause NOMI. These agents cause vasoconstriction and reduced blood flow in the mesentery, which may result in ischemia of the bowel.

• #2 Bowel Ischemia | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/18478

  Intestinal ischemia occurs when at least a 75% reduction in intestinal blood flow for more than 12 hours. […] Bowel ischemia can be classified as small intestine ischemia, which is commonly known as mesenteric ischemia and large intestine ischemia, which generally referred to as colonic ischemia. […] Generally, mesenteric ischemia (MI) can be divided based on the timing of onset into acute and chronic. […] Collateral circulation of the gastrointestinal tract can compensate for a 75% acute reduction in mesenteric perfusion for up to 12 hours without significant injury. […] Etiologies of acute intestinal ischemia can categorize as mesenteric arterial embolism (50%), intestinal hypoperfusion or nonocclusive mesenteric ischemia (NOMI) (20% to 30%), mesenteric arterial thrombosis (15% to 25%) and mesenteric venous thrombosis (MVT)(5%).

• #2 Non-Occlusive Mesenteric Ischemia in Cardiac Arrest Patients

  https://www.imrpress.com/journal/RCM/24/9/10.31083/j.rcm2409262/htm

  Non-occlusive mesenteric ischemia (NOMI) is a severe complication in patients after cardiac arrest (CA). […] The cause of this condition is mostly related to hypoperfusion of the intestine due to low cardiac output, spasm of mesenteric vessels, hypovolemia, or use of vasoconstrictive agents, which can significantly reduce the perfusion of the intestine and may result in transmural necrosis. […] The enterocytes are very sensitive to ischemia-reperfusion injury. […] Thus, depending on the duration of CA, especially in patients with prolonged CA, this process can aggravate a systemic inflammatory reaction with increased production of pro-inflammatory cytokines. […] Regarding the hypoperfusion and reperfusion that occur during cardiac arrest, NOMI is not only a severe complication of a critical state, but its incidence and severity are considered to be prognostic markers of CA outcome.

• #2 Chronic Mesenteric Ischemia: Background, Anatomy, Pathophysiology

  https://emedicine.medscape.com/article/183683-overview

  Chronic mesenteric ischemia (CMI) usually results from long-standing atherosclerotic disease of two or more mesenteric vessels. […] It is also a manifestation of peripheral vascular disease in which the metabolic demands of visceral organs are not being met by the blood supply. […] Symptoms are caused by the gradual reduction in blood flow to the intestine. […] In more than 95% of patients, the process driving mesenteric ischemia is diffuse atherosclerotic disease, which decreases the flow of blood to the bowel and is characterized by postprandial abdominal pain. […] As the atherosclerotic disease progresses, symptoms worsen. […] The interconnections between the celiac trunk, the superior mesenteric artery (SMA), and the inferior mesenteric artery (IMA) often permit easy compensation if stenotic lesions develop in 1 of these 3 vessels.

• #2 Intestinal Ischemia | Concise Medical Knowledge

  https://www.lecturio.com/concepts/intestinal-ischemia/

  Superior mesenteric vein: drains blood from the small intestine Small intestine The small intestine is the longest part of the GI tract, extending from the pyloric orifice of the stomach to the ileocecal junction. The small intestine is the major organ responsible for chemical digestion and absorption of nutrients. It is divided into 3 segments: the duodenum, the jejunum, and the ileum. Small Intestine: Anatomy. […] Sudden thrombus formation in addition to stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) can lead to acute-on-chronic mesenteric ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage.

• #2 Intestinal Ischemia | AMBOSS Rotation Prep

  https://resident360.amboss.com/adult-medicine/gastroenterology/intestinal-ischemia/intestinal-ischemia.html

  Although laboratory studies are nonspecific, lactic acidosis, leukocytosis, and an elevated D-dimer level may be seen in patients with suspected mesenteric ischemia. […] Immediate initiation of broad-spectrum antibiotics is recommended due to the high risk of infection associated with acute mesenteric ischemia. […] Once a diagnosis is made, definitive treatment involves a range of interventions, including endovascular or surgical repair. […] Colonic ischemia is the most frequent form of intestinal ischemia, and in contrast with mesenteric ischemia, generally results from nonocclusive causes such as small-vessel disease, systemic hypotension, decreased cardiac output, or aortic surgery. However, a specific inciting factor cannot be identified in most patients. […] Evaluation and diagnosis of colonic ischemia is similar to that of mesenteric ischemia except that large-vessel thrombus or embolus are seldom the cause of colonic ischemia. […] Most cases resolve spontaneously and thus treatment is generally supportive, with aggressive hydration, bowel rest, and occasionally antibiotics in moderate or severe disease due to risk for infection.

• #2 Colonic Ischemia – Intestinal Ischemia – Intestinal Diseases – Gastrointestinal Diseases – Gastroenterology – Diseases – McMaster Textbook of Internal Medicine

  https://empendium.com/mcmtextbook/chapter/B31.II.4.19.3.

  Segments of the intestine that are particularly vulnerable to ischemia include the region of the splenic flexure (ie, Griffiths point, where the IMA and SMA circulations meet and rely on collateral blood flow) and rectosigmoid junction (ie, Sudeck point, where blood flow is dependent on the terminal branches of the IMA). […] The right colon is less frequently involved in ischemic colitis but is vulnerable to low-flow states and embolic occlusion of the SMA because the ileocolic artery is the terminal branch of the SMA. […] The rectum is relatively unaffected due to its robust blood supply from both the mesenteric and iliac arteries.

• #2 Bowel Ischemia | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/18478

  In chronic mesenteric ischemia, the diffuse atherosclerotic disease is an account for 95% of cases. […] The splanchnic circulation varies based on the feeding or fasting state. […] Intestinal ischemia happens when inadequate oxygen delivered to the intestine. […] However, intestinal injury occurs by low perfusion and reperfusion of intestinal tissues. […] Low perfusion can cause intestinal injury when mesenteric perfusion pressure decreases about 30 mmHg or reduction of 45 mmHg in mean mesenteric arterial pressure. […] Physiologically, the intestine can compensate for about 75% of the reduction in mesentery blood flow for 12 hours without significant injury due to vasodilation of collateral circulation and increased oxygen extraction. […] However, after a prolongation of low perfusion or hypoxemia, progressive vasoconstriction leads to reducing collateral flow and subsequently full-thickness necrosis of the intestinal wall and perforation. […] Reperfusion injury after ischemia can be observed due to the release of toxic byproducts of ischemic injury, free oxygen radicals, and neutrophil activation.

• #2 Bowel Ischemia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK554527/

  However, after a prolongation of low perfusion or hypoxemia, progressive vasoconstriction leads to reducing collateral flow and subsequently full-thickness necrosis of the intestinal wall and perforation. […] Reperfusion injury after ischemia can be observed due to the release of toxic byproducts of ischemic injury, free oxygen radicals, and neutrophil activation.

• #2 Many faces of acute bowel ischemia: overview of radiologic staging | Insights into Imaging | Full Text

  https://insightsimaging.springeropen.com/articles/10.1186/s13244-021-00985-9

  Stage II or the intermediate stage is described as presence of specific pathologic changes (edema, erosion, hemorrhage and necrosis) in submucosa and muscularis propria. […] Stage III, the late stage, is manifested by transmural bowel necrosis and is developed if blood supply is not eventually restored. […] It should be noted that bowel ischemia accompanied by reperfusion injury may lead to the disruption of mucosal barrier followed by bacterial invasion, septic shock and multiorgan failure, which may cause death without transmural necrosis. […] Understanding the pathophysiology of ABI can help for better management. […] Management should be based on the latest stage identified. […] The main goal of management is to achieve a prompt diagnosis, specify the best treatment option and reduce mortality in these patients.

• #2 Intestinal Ischemia and Reperfusion: Consequences and Mechanisms | SpringerLink

  https://link.springer.com/10.1007/978-3-642-37078-6_240

  Ischemia and reperfusion of the ischemic intestine can result in significant tissue injury that is manifested as vascular dysfunction and mucosal barrier failure. […] The injury response to ischemia per se can be attributed to hypoxia and the cellular alterations brought about by this condition. […] Reperfusion of the ischemic intestine is accompanied by a more profound injury response that has been linked to the generation of reactive oxygen species that are derived from the enzyme xanthine oxidase. […] The accumulation of these reactive species at the time of reperfusion, coupled with the inactivation of nitric oxide, creates an inflammatory phenotype within the vasculature and mucosal membrane. […] The resulting recruitment of leukocytes and platelets and the activation of resident inflammatory cells that normally reside in the perivascular space (mast cells, macrophages) lead to further oxidative stress and a more intense inflammatory condition, ultimately resulting in capillary and mucosal membrane failure and organ dysfunction.

• #2 SciELO Brazil – Pathophysiology of mesenteric ischemia/reperfusion: a review Pathophysiology of mesenteric ischemia/reperfusion: a review

  https://www.scielo.br/j/acb/a/nsvfz8j9KBgNvs5GKQ7CznN/

  However, when the process which initiates ischemia is corrected before irreversible alterations can occur, oxygen return allows for the reestablishment of energetic metabolism, the removal of toxic products and the progressive return of normal cell functions. […] Depending on the time and intensity of the ischemia, when oxygen is reintroduced to the tissues, tissue injury can be further exacerbated (oxygen paradox). […] I/R can provoke complex interactions between the endothelium and different cell types, leading to microvascular injury, cellular necrosis and/or apoptosis. […] Occlusion and reperfusion of the splanchnic arteries precipitate circulatory shock, which, principally through an increase in vascular permeability, causes the activation and adhesion of polymorphonuclear neutrophils (PMNs), the release of proinflammatory substances and the formation of both nitrogen-derived and oxygen-derived free radicals.

• #2 SciELO Brazil – Pathophysiology of mesenteric ischemia/reperfusion: a review Pathophysiology of mesenteric ischemia/reperfusion: a review

  https://www.scielo.br/j/acb/a/nsvfz8j9KBgNvs5GKQ7CznN/

  The superoxide ions react with nitric oxide (NO) to produce peroxynitrite, which then causes accentuated lipid peroxidation, proteic and DNA modifications resulting in cellular damage. […] The activation of the complement system can lead to the translocation of NF-kB and an increase in the transcription of iNOS. […] The activation of neutrophils was also complement-dependent during intestinal I/R. […] The depletion or inhibition of the complement could diminish many of the mediators of I/R injury. […] The accumulation of platelets in the postischemic microvasculature could contribute significantly to the manifestation of I/R lesions. […] Serotonin together with other bioactive substances could perform an important function in the pathogenesis of intestinal I/R. […] It has been demonstrated recently that pancreatic proteases are involved in the production of inflammatory mediators after intestinal I/R.

• #2 MicroRNA-378 protects against intestinal ischemia/reperfusion injury via a mechanism involving the inhibition of intestinal mucosal cell apoptosis | Cell Death & Disease

  https://www.nature.com/articles/cddis2017508

  Intestinal ischemia/reperfusion (I/R) injury remains a major clinical event and contributes to high morbidity and mortality rates, but the underlying mechanisms remain elusive. […] The factors contributing to intestinal I/R injury were complex, including microvascular dysfunction, reactive oxygen species over-production, inflammation and even intestinal epithelial cell death. […] Many evidence reveals that apoptosis is a major mode of cell death caused by intestinal I/R, which is a complex biological process that can be triggered by the death receptor and mitochondrial death signaling pathways. […] Previous studies have documented that apoptosis is the main mode of intestinal mucosal cell death after intestinal I/R, and the exploration of the mechanisms of apoptosis might lead to effective therapy for organ I/R injury.

• #2 Mesenteric ischemia pathophysiology – wikidoc

  https://www.wikidoc.org/index.php/Mesenteric_ischemia_pathophysiology

  The factors that regulate the intestinal blood flow play a vital role in the development of mesenteric ischemia. […] Mesenteric ischemia occurs when intestinal blood supply is compromised by more than 50% of the original blood flow without activation of adaptive responses. This can lead to disruption of mucosal barrier, allowing the release of bacterial toxins (present in the intestinal lumen) and vasoactive mediators which ultimately lead to complete necrosis (cell death) of the intestinal mucosa. […] Intestinal mucosal damage occurs in response to ischemic insult. […] In response to providing protection from ischemia, mesenteric vessels undergo intrinsic autoregulation, which is an adaptive response to ischemia. […] In order to compensate for the ischemia, there is vasoconstriction of mesenteric vessels resulting in increased tissue oxygen extraction along with vasodilation of the collateral vessels. Owing to this mechanism, intestine is able to compensate for around 75% reduction in blood flow.

• #2 Biochemical markers of acute intestinal ischemia: possibilities and limitations

  https://atm.amegroups.org/article/view/20595/20750

  Acute intestinal ischemia is a relative rare abdominal emergency, associated with considerably high morbidity and mortality rates. […] The pathophysiology is complex and multifaceted. The intestinal acute vascular insufficiency leads to renin-angiotensin activation, sympathic stimulation, vasospasm and consequently hypoxia. […] The persistence of ischemia may then lead to an evolvement of transmural infarction towards irreversible injury and necrosis, intestinal perforation and release of bacteria and toxins into the systemic circulation. […] Despite ample research in this field, early, sensitive and specific biomarkers of acute intestinal ischemia have not been identified so far. […] The aim of this narrative review is hence to provide an overview on traditional laboratory biomarkers of acute intestinal ischemia and summarize current evidence regarding some emerging and potentially useful biomarkers.

• #2 Intestinal Ischemia: Unusual but Fearsome Complication of COVID-19 Infection

  https://www.mdpi.com/2227-9059/10/5/1010

  The pathophysiology of gastrointestinal damage in coronavirus disease (COVID-19) is probably multifactorial. It is not clear whether the etiology of intestinal ischemia may be directly related to viral replication or may result from hyper-coagulability following SARS-CoV-2 infection. […] Microvascular injury (ischemic enteritis, patchy bowel necrosis, presence of thrombi, and perivascular inflammation) was observed in the submucosal arterioles of the small intestine from patients with COVID-19. […] SARS-CoV-2 can cause direct injury of the gastrointestinal mucosa through its attachment to the angiotensin-converting enzyme receptor (ACE2), which is abundantly expressed on enterocytes, or by disruption of the normal colonic gut flora or by bowel ischemia resulting from thromboembolic complications.

• #2 Mesenteric Ischemia: Causes, Symptoms & Treatment

  https://my.clevelandclinic.org/health/diseases/23246-mesenteric-ischemia

  Narrowed and blocked arteries in the mesentery can cause ischemia, depriving your digestive tract of vital blood and oxygen. […] Without enough blood flow, the affected organs and tissues dont have enough oxygen and cant function correctly. If the blockage is severe enough, the affected organs and tissues may start to die. […] Chronic mesenteric ischemia often happens because of circulatory diseases that cause blood vessels to narrow. This narrowing, known as stenosis, means that blood flow to your mesentery drops over time. […] Non-occlusive mesenteric ischemia (NOMI), which happens without a blockage, makes up about 20% of all cases of acute mesenteric ischemia. Acute NOMI happens when blood vessels constrict, or there are spasms in the muscles lining those vessels. […] Chronic mesenteric ischemia may need some different treatments, depending on why it happens. But many of the possible treatments are the same as with acute mesenteric ischemia.

• #2 SciELO Brazil – Pathophysiology of mesenteric ischemia/reperfusion: a review Pathophysiology of mesenteric ischemia/reperfusion: a review

  https://www.scielo.br/j/acb/a/nsvfz8j9KBgNvs5GKQ7CznN/

  More recent studies indicate that apoptosis is clearly a significant and, perhaps, the principal contributor to cellular death after I/R injury. […] Apoptosis inhibitors in injured tissue can preserve functional and morphological integrity in organs submitted to I/R. […] Reactive chemical species initiate a sequence of events including the activation of neutrophils and the release of harmful substances like PAF and histamine. […] Multiple organ failure is a frequent complication after intestinal I/R and involves organs like the liver, heart, kidneys and lungs. […] The events which occur during I/R are complex and well studied, although, there still remain many doubts as to their pathophysiology and therapeutics, revealing the need for new research to obtain a more complete understanding and in the search for improved treatments.

• #2 Biochemical markers of acute intestinal ischemia: possibilities and limitations

  https://atm.amegroups.org/article/view/20595/20750

  Although D-lactate seems hence to perform better than L-lactate because of its exclusively intestinal source, the results obtained in different studies are mostly inconsistent. […] IMA is a biologic marker that can be easily and inexpensively measured in clinical laboratories by using the albumin cobalt binding (ACB) assay or with an enzyme-linked immunosorbent assay (ELISA). […] A progressively decreasing intestinal perfusion and a loss of integrity of the enterocyte cell membrane both contribute the rapid release of I-FABP into circulation and further elimination by the kidneys. […] Although acute intestinal ischemia remains a relative rare condition, a timely and accurate diagnosis is needed to prevent the development of serious complications, up to death.

• #2 Targeting cell death pathways in intestinal ischemia-reperfusion injury: a comprehensive review | Cell Death Discovery

  https://www.nature.com/articles/s41420-024-01891-x

  During post-ischemic reperfusion, stimulation and damage to the intestine increase, primarily due to the buildup of metabolites generated during ischemia and the release of oxygen free radicals. Under such conditions, the gut undergoes non-programmed cell death. […] The activation of multiple signaling pathways leads to the initiation of various mechanisms of cell death. […] Intestinal I/R injury induces apoptosis and necrosis in the intestinal epithelial cells, which results in impaired intestinal barrier function and ultimately leads to multiple organ dysfunction syndrome. […] The inflammatory response drives the occurrence of apoptosis and necrosis. […] The occurrence of pyroptosis in intestinal I/R injury was confirmed by histopathological findings and intestinal barrier indices, including transepithelial electrical resistance (TER), tight-junction protein, and serum biomarkers.

• #2 Delayed Diagnosis of Mesenteric Ischemia | PSNet

  https://psnet.ahrq.gov/web-mm/delayed-diagnosis-mesenteric-ischemia

  A definitive diagnosis for acute ischemia requires either exploration in the operating room or, more commonly, computed tomographic (CT) angiography of the abdomen to evaluate the mesenteric vessels and bowel viability. […] Once diagnosed, initial management consists of fluid resuscitation, broad spectrum antibiotics, anticoagulation in most cases, and urgent surgical consultation to General Surgery and Vascular Surgery for abdominal exploration. […] Outcomes of this disease process depend on the etiology, with higher mortality in arterial (50-70%) compared to venous ischemia (30%). […] Unfortunately, mortality rates exceed 60% in acute mesenteric ischemia and these high mortality rates have been unchanged in recent series.

• #3 Bowel Ischemia – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK554527/

  Intestinal ischemia occurs when at least a 75% reduction in intestinal blood flow for more than 12 hours. […] Generally, mesenteric ischemia (MI) can be divided based on the timing of onset into acute and chronic. […] Collateral circulation of the gastrointestinal tract can compensate for a 75% acute reduction in mesenteric perfusion for up to 12 hours without significant injury. […] The splanchnic circulation varies based on the feeding or fasting state. Despite high intestinal vasculature, oxygen extraction is low from the intestinal arteries. […] Intestinal ischemia happens when inadequate oxygen delivered to the intestine. However, intestinal injury occurs by low perfusion and reperfusion of intestinal tissues. […] Low perfusion can cause intestinal injury when mesenteric perfusion pressure decreases about 30 mmHg or reduction of 45 mmHg in mean mesenteric arterial pressure.

• #3 Intestinal ischemia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/intestinal-ischemia/symptoms-causes/syc-20373946

  Intestinal ischemia often is split into groups. Colon ischemia, also called ischemic colitis, affects the large intestine. Other types of ischemia affect the small intestine. These are acute mesenteric ischemia, chronic mesenteric ischemia and ischemia due to mesenteric venous thrombosis. […] Acute mesenteric ischemia is the result of a sudden loss of blood flow to the small intestine. It may be due to: A blood clot, also called an embolus, that comes loose in the heart and travels through the blood to block an artery. It most often blocks the superior mesenteric artery, which sends oxygen-rich blood to the intestines. […] Chronic mesenteric ischemia is due to the buildup of fatty deposits on an artery wall, called atherosclerosis. The disease process most often is slow. It’s also called intestinal angina because it’s due to less blood flow to the intestines after eating.

• #3 Chronic Mesenteric Ischemia: Background, Anatomy, Pathophysiology

  https://emedicine.medscape.com/article/183683-overview

  Usually, therefore, at least 2 of the 3 major visceral vessels must be occluded or narrowed for chronic mesenteric ischemia (CMI) to develop. […] CMI with intestinal hypoperfusion is rarely seen in clinical practice, but when it does occur, it represents a serious and complex vascular disorder. […] Although the pathophysiologic mechanism by which ischemia produces pain is still not completely understood, current physiologic understanding of splanchnic perfusion suggests a key role for the splanchnic circulation in the regulation of cardiovascular homeostasis. […] Conditions less frequently involved in the pathogenesis of CMI are celiac artery compression syndrome (CACS; also known as median arcuate ligament syndrome [MALS]) and fibromuscular dysplasia (FMD).

• #3 Mesenteric ischemia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/mesenteric-ischemia/symptoms-causes/syc-20374989

  In mesenteric ischemia, a blockage in an artery cuts off blood flow to a portion of the intestine. […] Mesenteric ischemia is a condition that happens when narrowed or blocked arteries restrict blood flow to your small intestine. Decreased blood flow can permanently damage the small intestine. […] Acute mesenteric ischemia is most commonly caused by a blood clot in the main mesenteric artery. The blood clot often starts in the heart. The chronic form is most commonly caused by a buildup of fatty deposits, called plaque, that narrows the arteries. […] If not treated promptly, acute mesenteric ischemia can lead to irreversible bowel damage. Not getting enough blood flow to the bowel can cause parts of the bowel to die. […] People with chronic mesenteric ischemia can develop acute-on-chronic mesenteric ischemia. Symptoms of chronic mesenteric ischemia can get worse, leading to the acute form of the condition.

• #3 Bowel Ischemia | Treatment & Management | Point of Care

  https://www.statpearls.com/point-of-care/18478

  In chronic mesenteric ischemia, the diffuse atherosclerotic disease is an account for 95% of cases. […] The splanchnic circulation varies based on the feeding or fasting state. […] Intestinal ischemia happens when inadequate oxygen delivered to the intestine. […] However, intestinal injury occurs by low perfusion and reperfusion of intestinal tissues. […] Low perfusion can cause intestinal injury when mesenteric perfusion pressure decreases about 30 mmHg or reduction of 45 mmHg in mean mesenteric arterial pressure. […] Physiologically, the intestine can compensate for about 75% of the reduction in mesentery blood flow for 12 hours without significant injury due to vasodilation of collateral circulation and increased oxygen extraction. […] However, after a prolongation of low perfusion or hypoxemia, progressive vasoconstriction leads to reducing collateral flow and subsequently full-thickness necrosis of the intestinal wall and perforation. […] Reperfusion injury after ischemia can be observed due to the release of toxic byproducts of ischemic injury, free oxygen radicals, and neutrophil activation.

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