Update on Colon Ischemia: Recent Insights and Advances

Effects of butyrate on intestinal ischemia-reperfusion injury via the HMGB1-TLR4-MyD88 signaling pathway

BACKGROUND

This study combined bioinformatics and experimental verification in a mouse model of intestinal ischemia-reperfusion injury (IRI) to explore the protection mechanism exerted by butyrate against IRI.

METHODS

GeneCards, Bioinformatics Analysis Tool for Molecular Mechanisms of Traditional Chinese Medicine and GSE190581 were used to explore the relationship between butyrate and IRI and aging. Protein-protein interaction networks involving butyrate and IRI were constructed via the STRING database, with hub gene analysis performed through Cytoscape. Functional enrichment analysis was conducted on intersection genes. A mouse model of IRI was established, followed by direct arterial injection of butyrate. The experiment comprised five groups: normal, sham, model, vehicle, low-dose butyrate, and high-dose butyrate. Intestinal tissue observation was done via transmission electron microscopy (TEM), histological examination via hematoxylin and eosin (H&E) staining, tight junction proteins detection via immunohistochemistry, and Western blot analysis of hub genes. Drug-target interactions were evaluated through molecular docking.

RESULTS

Butyrate protected against IRI by targeting 458 genes, including HMGB1 and TLR4. Toll-like receptor pathway was implicated. Butyrate improved intestinal IRI by reducing mucosal damage, increasing tight junction proteins, and lowering levels of HMGB1, TLR4, and MyD88. Molecular docking showed strong binding energies between butyrate and HMGB1 (-3.7 kcal/mol) and TLR4 (-3.8 kcal/mol).

CONCLUSIONS

According to bioinformatics predictions, butyrate mitigates IRI via multiple-target and multiple-channel mechanisms. The extent of IRI can be reduced by butyrate through the inhibition of the HMGB1-TLR4-MyD88 signaling pathway, which is related to senescence.

The usefulness of indocyanine green fluorescence imaging for intestinal perfusion assessment of intracorporeal anastomosis in laparoscopic colon cancer surgery

PURPOSE

The purpose of this study was to clarify the usefulness of indocyanine green fluorescence imaging (ICG-FI) in the assessment of intestinal vascular perfusion in patients who receive intracorporeal anastomosis (IA) in colon cancer surgery.

METHODS

This was a single-center, retrospective study using propensity score matching. We compared the surgical outcomes of colon cancer patients who underwent laparoscopic colonic resection with IA or external anastomosis (EA) with the intraoperative evaluation of anastomotic perfusion using ICG-FI from January 2019 to July 2021. The detection rate of poor anastomotic perfusion by ICG-FI was examined.

RESULTS

A total of 223 patients were enrolled. After matching, 69 patients each were classified into the IA and EA groups. There were no significant differences in age, sex, body mass index, tumor localization, or progression between the two groups. The operation time was similar (172 min vs. 171 min, p = 0.62) and the amount of bleeding was significantly lower (0 ml vs. 2 ml, p = 0.0023) in the IA group. The complication rates (grade ≥ 2) of the two groups were similar (14.5% vs. 11.6%, p = 0.59). ICG-FI identified four patients (5.8%) with poor anastomotic perfusion in the IA group, but none in the EA group (p = 0.046). All four patients with poor perfusion in the IA group underwent additional resection; none of these patients developed postoperative complications.

CONCLUSION

Poor anastomotic perfusion was detected in 5.8% of cases who underwent laparoscopic colon cancer surgery with IA. ICG-FI is useful for evaluating anastomotic perfusion in IA in order to prevent AL.

Clinical characteristics and long-term outcomes of hospitalised patients with ischemic colitis with different degrees of haematochezia: a retrospective study

BACKGROUND

Based on the literature, haematochezia is associated with a benign clinical course of ischaemic colitis. However, most cases in the literature presented mild haematochezia associated with ischaemic colitis. Therefore, we aimed to investigate the impact of different degrees of haematochezia on the clinical outcomes of ischaemic colitis.

METHODS

Patients were divided into nonhaematochezia, mild-haematochezia, and severe-haematochezia cohorts stratified by the degree of haematochezia. The clinical characteristics and prognoses were retrospectively reviewed.

RESULTS

Haematochezia cohort (n = 89) was associated with a lower rate of severe illness (25% vs. 52%, P = 0.001), lower rate of isolated right colon ischaemia (7% vs. 28%, P = 0.001), lower surgery rates (13% vs. 36%, P = 0.001), and shorter hospital stay (12 vs. 17 days, P < 0.001) compared with nonhaematochezia cohort (n = 50). Severe-haematochezia cohort (n = 11) had a higher frequency of severe illness (73% vs. 18%, P < 0.001), higher surgical intervention rate (55% vs. 6%, P < 0.001), higher nonsurgical complication rate, higher in-hospital mortality (45% vs. 0%, P < 0.001), and longer hospital stay (28 vs. 10  days, P = 0.001), compared with mild-haematochezia cohort (n = 78). Additionally, in-hospital mortality (45% vs. 6%, P = 0.003) and nonsurgical complication rate were higher in the severe-haematochezia than in the nonhaematochezia cohort. However, the three cohorts had comparable prognoses for long-term survival and recurrence.

CONCLUSIONS

Mild haematochezia was related to a benign clinical course of ischaemic colitis, while lack of haematochezia or severe haematochezia was associated with worse hospitalisation outcomes.

Errors in MDCT diagnosis of acute mesenteric ischemia

The causes of diagnostic errors during daily medical practice can be several, mainly attributable to perceptual, interpretive and communication factors. The eventuality of radiological error is much more amplified in the emergency setting where a high number of complex multidetector-row computed tomography (MDCT) images must be evaluated quickly and critical time decisions need to be taken. In particular, in this context, the diagnosis of vascular intestinal diseases represents a crucial and difficult challenge in case of acute abdominal pain given the importance of being able to identify patient with high suspicious for intestinal ischemia and for a specific patient to judge if his ischemia is reversible or irreversible. Awareness of potential biases which can lead to diagnostic errors together with an extensive knowledge of the imaging features of these pathologies can lead to promptly recognize them with fewer mistakes, improving patients' outcome. This article reviews the MDCT findings of acute intestinal ischemia and acute colonic ischemia and analyzes the main types of diagnostic errors, underlining the importance of being familiarized with them to avoid misdiagnosis.

Factors influencing hospital stay duration for patients with mild ischemic colitis: a retrospective study

Background

Ischemic colitis is the most prevalent ischemic injury of the gastrointestinal tract. The majority of patients with mild ischemic colitis usually achieve complete clinical recovery shortly. However, the predictors of longer hospital stay duration are unclear. This study aimed to evaluate the predictors of hospital stay duration for patients with mild ischemic colitis.

Methods

We retrospectively evaluated 100 patients with mild ischemic colitis between January 2010 and December 2020 at Xiangya Hospital (a tertiary care center). The clinical characteristics and therapeutic drugs of patients who were hospitalized for ≤ 8 days and ≥ 12 days were compared.

Results

Of the 100 patients included, 63 (63%) were hospitalized for ≤ 8 days and 37 (37%) were hospitalized for ≥ 12 days. Patients with cerebrovascular disease (29.7% vs. 11.1%, p = 0.019) and abdominal surgical history (29.7% vs. 7.9%, p = 0.004) were more likely to be hospitalized for ≥ 12 days than for ≤ 8 days. The d-dimer levels [0.78 (0.41–1.82) vs. 0.28 (0.16–0.73), p = 0.001] and positive fecal occult blood test results (86.5% vs. 60.3%, p = 0.006) were higher in patients who were hospitalized for ≥ 12 days than in those who were hospitalized for ≤ 8 days. Probiotic use was greater in patients hospitalized for ≤ 8 days (76.2% vs. 54.1%, p = 0.022). Multivariate analysis indicated that cerebrovascular disease (odds ratio [OR] = 4.585; 95% confidence interval [CI] 1.129–18.624; p = 0.033), abdominal surgical history (OR = 4.551; 95% CI 1.060–19.546; p = 0.042), higher d-dimer levels (OR = 1.928; 95% CI 1.024–3.632; p = 0.042), and higher positive fecal occult blood test results (OR = 7.211; 95% CI 1.929–26.953; p = 0.003) were associated with longer hospital stays.

Conclusion

Cerebrovascular disease, abdominal surgical history, higher d-dimer levels, and higher positive fecal occult blood test results are independent and significant factors that influence longer hospital stays for patients with mild ischemic colitis. Probiotics helped reduce hospital stay in these patients.

Bad blood: ischemic conditions of the large bowel

PURPOSE OF REVIEW

Colon ischemia is the most common form of intestinal ischemic injury and is seen frequently in an elderly population. This disease is usually self-limited, and many causes have been identified. The recent literature has focused on estimates of prognosis, triaging appropriate level of care, and identification of optimal treatments. In this review, we will address our current understanding of colon ischemia including epidemiology, pathophysiology, segmental distribution, presentation, diagnosis, and management.

RECENT FINDINGS

Research has recently been focused on factors associated with poor outcome. The medical comorbidities identified include chronic obstructive pulmonary disease (COPD), hepatic cirrhosis, and chronic aspirin use. Serological markers are noninvasive tools that can triage severity. Recent studies have shown procalcitonin, C-reactive protein, D-dimer, and neutrophil counts can help predict those at greatest risk for poor outcome. The timing of colonoscopy relative to symptomatic onset also can help predict severity. Early colonoscopy allows for quicker identification of ischemic stigmata, reducing the chance of misdiagnosis and potentially unnecessary and harmful treatment. The treatment of colon ischemia has classically been conservative with antimicrobials reserved for those with moderate or severe disease. Recent retrospective analysis calls into question the utility of antibiotics in the treatment of colon ischemia, although the data is not convincing enough to advise against antimicrobial treatment in patients with severe and fulminant disease.

SUMMARY

It is an exciting time for research focused on colon ischemia. With an improved knowledge, awareness of associated risk factors and predictors of severity, clinicians now have enhanced clinical tools to diagnose and triage patients earlier in the disease. This should help institute prompt and appropriate therapies ultimately improving outcomes.

Colonoscopy-related colonic ischemia

Colonoscopy is a risk factor for colon ischemia. The colon is susceptible to ischemia due to its minor blood flow compared to other abdominal organs; the etiology of colon ischemia after colonoscopy is multifactorial. The causative mechanisms include splanchnic circulation impairment, bowel preparation, drugs used for sedation, bowel wall ischemia due to insufflation/barotrauma, and introduction of the endoscope. Gastroenterologists must be aware of this condition and its risk factors for risk minimization, early diagnosis, and proper treatment.

Does the Route of Cocaine Use Affect the Mortality and Outcomes of Cocaine-Induced Intestinal Ischemia? A Systematic Review

Intestinal ischemia results from diminished perfusion of the colon resulting in tissue hypoxia. Anecdotal reports suggest that cocaine-induced intestinal ischemia has the highest mortality and longer length of stay among the vasoconstrictors. The present study aimed to summarize the available studies in the literature to assess the effect of routes of consumption on the outcomes of cocaine-induced intestinal ischemia. We conducted a systematic search of MEDLINE from inception through October 2019. Studies of cocaine-induced intestinal ischemia were included if data were available on comorbidities, mortality, and hospital length of stay (LOS). The study's primary outcomes were mortality and need for surgery, while secondary outcomes included the hospital length of stay, LACE index, and hospital score. Statistical tests used included linear and binary logistic regression. STATA 2015 was used, and P < 0.05 was statistically significant. Of the 304 studies, 8 case series and 45 case reports (n = 69 patients) met the inclusion criteria. Different routes of cocaine use had similar mortality odds and the need for surgery for intestinal ischemia. Hospital LOS showed significant difference among the subgroups. Readmission scores (LACE and hospital score) were higher for intravenous and smoking than ingestion and intranasal use (P < 0.05). In conclusion, different routes of cocaine use appear to have similar mortality odds for intestinal ischemia, which vary significantly among the different routes of cocaine consumption for the length of stay and readmission scores. Prompt recognition of the route of cocaine use is vital to improve the outcome. Large-scale and well-designed observational studies are needed to investigate this topic further.

Homozygous Factor V Leiden presenting as irreversible chronic colon ischemia resulting from inferior mesenteric vein thrombosis

A 42-year-old man presented with 6 months of unexplained left lower quadrant abdominal pain and hematochezia accompanied by weight loss despite extensive evaluations. Stool studies for pathogens were unrevealing, but an abdominal contrast-enhanced computed tomography revealed findings of chronic inferior mesenteric vein thrombosis. Colonoscopy demonstrated ulcerated strictures and gangrene confined to the sigmoid and descending colons, and biopsies confirmed changes of chronic irreversible colon ischemia. A homozygous Factor V Leiden mutation was diagnosed. The patient underwent colectomy and was treated with lifelong anticoagulation. While mesenteric venous thrombosis is a well-recognized cause of colon ischemia in hypercoagulable states, thrombosis of the inferior mesenteric vein is uncommon; when chronic it is rarely clinically apparent. Similarly, while Factor V Leiden mutation is a common hereditary thrombophilia, it uncommonly causes mesenteric venous thrombosis, and homozygotes of the mutation typically present earlier in the fourth decade and with non-mesenteric venous thromboembolism. This case is valuable and adds to the existing literature in describing a rare, clinically atypical, and late index presentation of homozygous Factor V Leiden mutation as chronic inferior mesenteric vein thrombosis yielding irreversible colon ischemia.

Ischaemic colitis diagnosed by sigmoidoscopy during pregnancy

A 21-year-old woman visited out hospital for lower abdominal pain and bloody diarrhoea at 19 weeks of pregnancy. Endoscopic findings revealed longitudinal ulcerations with hyperaemia and oedema in the sigmoid colon. These findings and clinical presentation confirmed the diagnosis of ischaemic colitis. Conservative treatment, including fasting and intravenous hydration, was administered, and the patient made a good recovery. After discharge, there was no recurrence during pregnancy and postpartum period. It is important to make early diagnosis and treatment, and multidisciplinary teamwork between obstetricians, gastroenterologist and endoscopist is required.

Low-dose aspirin and the severity of ıschemic colitis: A single-center retrospective study

BACKGROUND/AIMS

This retrospective study aimed to evaluate the effect of low-dose aspirin (50-150 mg/d) on the severity of ischemic colitis.

MATERIALS AND METHODS

A total of 244 patients admitted to our hospital for ischemic colitis between 2013 and 2018 were included in the study. Patients were divided into two groups-aspirin and non-aspirin groups-based on their recent history of aspirin use before the onset of ischemic colitis. Clinical performance, biochemical indices, and endoscopic findings were compared.

RESULTS

The average age and the proportion of underlying disease, including hypertension, cerebral infarction, and coronary heart disease in the aspirin group was significantly higher than those in the non-aspirin group (p<0.05). In terms of clinical symptoms, the proportion of diarrhea in the aspirin group was significantly higher than that in the non-aspirin group, while the proportion of abdominal pain was significantly lower in the aspirin group compared with the non-aspirin group. Colonoscopy results showed that the incidence of ulceration was significantly higher in the aspirin group than in the non-aspirin group (p<0.05).

CONCLUSION

The use of low-dose aspirin may aggravate the severity and mask the symptoms of abdominal pain in ischemic colitis.

Nationwide Study to Predict Colonic Ischemia after Abdominal Aortic Aneurysm Repair in The Netherlands

BACKGROUND

Colonic ischemia remains a severe complication after abdominal aortic aneurysm (AAA) repair and is associated with a high mortality. With open repair being one of the main risk factors of colonic ischemia, deciding between endovascular or open aneurysm repair should be based on tailor-made medicine. This study aims to identify high-risk patients of colonic ischemia, a risk that can be taken into account while deciding on AAA treatment strategy.

METHODS

A nationwide population-based cohort study of 9,433 patients who underwent an AAA operation between 2014 and 2016 was conducted. Potential risk factors were determined by reviewing prior studies and univariate analysis. With logistic regression analysis, independent predictors of intestinal ischemia were established. These variables were used to form a prediction model.

RESULTS

Intestinal ischemia occurred in 267 patients (2.8%). Occurrence of intestinal ischemia was seen significantly more in open repair versus endovascular aneurysm repair (7.6% vs. 0.9%; P < 0.001). This difference remained significant after stratification by urgency of the procedure, in both intact open (4.2% vs. 0.4%; P < 0.001) and ruptured open repair (15.0% vs. 6.2%); P < 0.001). Rupture of the AAA was the most important predictor of developing intestinal ischemia (odds ratio [OR], 5.9, 95% confidence interval [CI] 4.4-8.0), followed by having a suprarenal AAA (OR 3.4; CI 1.1-10.6). Associated procedural factors were open repair (OR 2.8; 95% CI 1.9-4.2), blood loss >1L (OR 3.6; 95% CI 1.7-7.5), and prolonged operating time (OR 2.0; 95% CI 1.4-2.8). Patient characteristics included having peripheral arterial disease (OR 2.4; 95% CI 1.3-4.4), female gender (OR 1.7; 95% CI 1.2-2.4), renal insufficiency (OR 1.7; 1.3-2.2), and pulmonary history (OR 1.6; 95% CI 1.2-2.2). Age <68 years proved to be a protective factor (OR 0.5; 95% CI 0.4-0.8). Associated mortality was higher in patients with intestinal ischemia versus patients without (50.6% vs. 5.1%, P < 0.001). Each predictor was given a score between 1 and 4. Patients with a score of ≥10 proved to be at high risk. A prediction model with an excellent AUC = 0.873 (95% CI 0.855-0.892) could be formed.

CONCLUSIONS

One of the main risk factors is open repair. Several other risk factors can contribute to developing colonic ischemia after AAA repair. The proposed prediction model can be used to identify patients at high risk for developing colonic ischemia. With the current trend in AAA repair leaning toward open repair for better long-term results, our prediction model allows a better informed decision can be made in AAA treatment strategy.

Mesenteric phlebosclerosis with amyloidosis in association with the long-term use of medicinal liquor: A case report

BACKGROUND

Mesenteric phlebosclerosis (MP) is a rare disease of the colon. The clinical manifestations of this disease are nonspecific and it may easily be misdiagnosed. We report a case of MP with amyloidosis in the colonic vessel walls in a patient with hypertension who had been consuming Chinese medicinal liquor for 10 years. We also review the relevant literature and summarize the characteristics of MP in patients in mainland China.

CASE SUMMARY

A 64-year-old man was referred to our department from his primary hospital because of abdominal pain, diarrhea, and fever for almost 10 d. Computed tomography showed colon wall thickening, with threadlike calcifications in the mesenteric vein in the transverse colon. Colonoscopy revealed purple-blue mucosa with multiple ulcers in the ascending and transverse colon. Biopsy showed thickening and calcification of the vein walls, perivascular and mucosal collagen degeneration, and amyloidosis. The patient had been consuming Chinese medicinal liquor, mainly that made from gardenia fruit, for 10 years. Based on these results, a diagnosis of MP with amyloidosis was made. After conservative treatment, the patient’s discomfort subsided and he was followed closely. The use of Chinese herbal medicine was suspected to play a role in the pathogenesis of MP.

CONCLUSION

The clinical manifestations of MP are nonspecific. Recognition of its typical imaging findings, including multiple calcifications on computed tomography and purple-blue mucosal discoloration on colonoscopy, is vital.

Educational Case: Ischemic Disorders of the Gut in Adult Patients

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, see http://journals.sagepub.com/doi/10.1177/2374289517715040. ¹.

Early Endoscopy Is Associated with Better Clinical Outcomes in Patients Hospitalized with Ischemic Bowel Disease

BACKGROUND AND AIMS

Providing diagnostic and therapeutic interventions, lower gastrointestinal endoscopy is a salient investigative modality for ischemic bowel disease (IB). As studies on the role of endoscopic timing on the outcomes of IB are lacking, we sought to clarify this association.

METHODS

After identifying 18-to-90-year-old patients with a primary diagnosis of IB from the 2012-2014 Healthcare Cost and Utilization Project-Nationwide Inpatient Sample, we grouped them based on timing of endoscopy into three: early (n = 9268), late (n = 3515), and no endoscopy (n = 18,452). We explored the determinants of receiving early endoscopy, the impact of endoscopic timing on outcomes (mortality and 13 others), and the impact of the type of endoscopy (colonoscopy vs. sigmoidoscopy) on these outcomes among the early group (SAS 9.4).

RESULTS

Less likely to receive early endoscopy were Blacks compared to Whites (adjusted odds ratio [aOR] 0.81 95% CI [0.70-0.94]), and individuals on Medicaid, Medicare, and uninsured compared to the privately insured group (aOR 0.80 [0.71-0.91], 0.70 [0.58-0.84], and 0.68 [0.56-0.83]). Compared to the late and no endoscopy groups, patients with early endoscopy had less mortality (aOR 0.53 [0.35-0.80] and 0.09 [0.07-0.12]), shorter length of stay (LOS, 4.64 [4.43-4.87] days vs. 8.87 [8.40-9.37] and 6.62 [6.52-7.13] days), lower total hospital cost (THC, $41,055 [$37,995-$44,361] vs. $72,598 [$66,768-$78,937] and $68,737 [$64,028-$73,793]), and better outcomes. Similarly, among those who received early endoscopy, colonoscopy had better outcomes than sigmoidoscopy for mortality, THC, LOS, and adverse events.

CONCLUSION

Early endoscopy, especially colonoscopy, is associated with better clinical outcomes and decreased healthcare utilization in IB. Unfortunately, there are disparities against Blacks, and non-privately insured individuals in receiving early endoscopy.

Older patients are significantly more likely to have colon ischaemia-associated conditions that are chronic and complex

BACKGROUND

Colon ischaemia is a common disease which has been associated with various medications and comorbidities.

AIM

To test the hypothesis that there are differences in the frequencies of these associations in older compared with younger patients.

METHODS

A retrospective cohort study was performed of patients hospitalized with colon ischaemia at two major medical centres from 2005-2017. Clinical, colonoscopic and pathologic criteria were used to identify patients admitted with colon ischaemia; patients with other types of colitis were excluded. Demographic and medical data were extracted. Two cohorts were created: patients aged 18-64 years and patients > 65 years. These were compared using SAS 14.3.

RESULTS

A total of 788 patients were included, of which 271 (34.4%) were of ages 18-64 years, and 517 (66.6%) were 65 years old or older. In the older cohort, constipation-inducing medications (83.8% vs 64.1%; P = <0.0001), diuretics (38.1% vs 25.1%; P = <0.001) and nonsteroidal anti-inflammatory drugs (58% vs 41.5%; P = <0.0001) were more common than in the younger cohort. Antipsychotic medication use was more common in the younger cohort (10.4% vs 5.4%; P = 0.01). There was a higher percentage of younger patients with a history of hypercoaguable state (1.9% vs 0.2%; P = 0.03) and dialysis dependence (22.9% vs 8.7%; P = <0.01), while a higher percentage of patients in the older cohort had a history of chronic obstructive pulmonary disease (12% vs 6.3%; P = 0.01) or atrial fibrillation (18.9% vs 10.3%; P = <0.01).

CONCLUSIONS

Our study shows that older patients are more likely to have colon ischaemia-associated conditions that are chronic and complex, while younger patients are more likely to have acute colon ischaemia-associated conditions.

The Colonic Single Stripe Sign: A Case of Ischemic Colitis

Sudden, transient reduction in the blood flow especially in the “watershed” regions of the colon can lead to intestinal ischemia causing a decrease in the delivery of oxygen and nutrients to the intestinal wall. Patients with ischemic colitis often have elevated white blood cell counts, serum lactate, and serum amylase levels. Colonoscopy can confirm the diagnosis of ischemia and the findings include edematous, friable mucosa, erythema with interspersed pale areas, scattered hemorrhagic erosions or linear ulcerations. A single, linear ulcer running along the anti-mesenteric colonic wall, "single-stripe sign"- favors the diagnosis of ischemic colitis. Management of mild and moderate colonic ischemia includes supportive care with bowel rest, gastric suction for associated ileus, fluid-electrolyte balance, and broad-spectrum antibiotics. Patients with severe colonic ischemia may require abdominal exploration and colectomy.

MDCT in acute ischaemic left colitis: a pictorial essay

The pathogenesis of acute ischaemic colitis depends on two different forms of vascular colonic insult: occlusive injury and non-occlusive injury. Clinically, ischaemic colitis may be classified as two major forms: mild (non-gangrenous) and acute fulminant (gangrenous). The classic presentation is abdominal pain, diarrhoea and/or rectal bleeding, but it is not specific and highly variable and so the diagnosis usually depends on clinical suspicion and is supported by serologic and colonoscopic findings. Imaging methods have their role in diagnosing IC. While plain radiography and ultrasound can orient the diagnosis, CT allows to define the morphofunctional alterations discriminating the non-occlusive forms from the occlusive forms and in most cases to estimate the timing of ischaemic damage. Purpose of the review is to define the role of CT in the early identification of pathological findings and in the definition of evolution of colonic ischaemic lesions, in order to plan the correct therapeutic approach, suggesting the decision of medical or surgical treatment.

Novel Insights Into the Mechanisms of Abdominal Pain in Obstructive Bowel Disorders

Obstructive bowel disorders (OBD) are characterized by lumen distention due to mechanical or functional obstruction in the gut. Abdominal pain is one of the main symptoms in OBD. In this article, we aim to critically review the potential mechanisms for acute and chronic pain in bowel obstruction (BO). While clustered contractions and associated increase of intraluminal pressure may account for colicky pain in simple obstruction, ischemia may be involved in acute pain in severe conditions such as closed loop obstruction. Recent preclinical studies discovered that visceral sensitivity is increased in BO, and visceral hypersensitivity may underlie the mechanisms of chronic abdominal pain in BO. Mounting evidence suggests that lumen distension, as a circumferential mechanical stretch, alters gene expression (mechano-transcription) in the distended bowel, and mechano-transcription of nociceptive and inflammatory mediators plays a critical role in the development of visceral hypersensitivity in BO. Mechano-transcription of nerve growth factor (NGF) in gut smooth muscle cells is found to increase voltage-gated Na⁺ channel (Na_v) activity of the primary sensory neurons by up-regulating expression of TTX-resistant Na_v1.8, whereas mechanical stretch-induced brain-derived neurotrophic factor (BDNF) reduces K_v currents especially A-type (IA) currents by down-regulating expression of specific IA subtypes such as K_v1.4. The NGF and BDNF mediated changes in gene expression and channel functions in the primary sensory neurons may constitute the main mechanisms of visceral hypersensitivity in OBD. In addition, mechanical stretch-induced COX-2 and other inflammatory mediators in the gut may also contribute to abdominal pain by activating and sensitizing nociceptors.

Corrupted Colonic Crypts Bordering Regenerating Mucosal Ulcers in Ulcerative Colitis

BACKGROUND/AIM

Histology in protracted ulcerative colitis (UC) discloses high numbers of chronic inflammatory cells and crypts with architectural distortions. In severe cases, ulcerations are frequently found. The histogenesis of colonic crypts with architectural distortions in UC remains elusive. A recent review of colectomy specimens from patients with UC revealed crypts surrounding mucosal ulcerations exhibiting severe architectural distortions. They were called corrupted colonic crypts, CCCs.

MATERIAL AND METHODS

Archival hematoxylin and eosin (H&E)-stained sections from three colectomies having several mucosal ulcers were selected for the study. The mucosa bordering mucosal ulcers was particularly scrutinized.

RESULTS

The review of 49 sections (mean=16.3, range=14-20) in the three colectomies revealed 60 ulcers (mean=20, range=13-27). The following CCC phenotypes were found bordering mucosal ulcers: with asymmetric lateral fission (n=11), with dual or three-foiled corrupted fission (n=19), with cystic dilatations (n=3), L-shaped crypts (n=7), T-inverted crypts (n=6), shoe-shaped crypts (n=3), horizontal crypts (n=14), multi-lobate crypts (n=2), and/or inter-connecting crypts (n=5).

CONCLUSION

The regeneration of ulcers in UC seems to proceed with neo-formation of corrupted crypts. In the same colectomies, none to occasional CCCs were found in large areas of the mucosa having severe chronic inflammation. Importantly, none of the occasional CCCs were found in other diseases of the colonic mucosa with chronic inflammation or in unspecific ulcers of the colon. Since neither chronic mucosal inflammation per se, nor unspecific ulcers of the colon are central for the formation of CCCs, it is suggested that crypt distortions of the non-ulcerated colonic mucosa in patients with UC might mirror formerly healed mucosal ulcerations.

Molecular imaging of Toll-like receptor 4 detects ischemia-reperfusion injury during intussusception

We investigated the expression of Toll-like receptor 4 (TLR4) in the acute phase of intestinal I/R injury during intussusception and evaluated whether anti-TLR4 antibody-conjugated lead sulfide quantum dots (TLR4-PbS QDs) could be used to detect and monitor the injury. We first established a mouse model of I/R injury during intussusception. TLR-PbS QDs were then intravenously administered to intestinal I/R injured mice and visualized using whole-body fluorescence imaging in the second near-infrared window (NIR-II). Immunohistochemical analysis of intestinal tissue from the mice revealed that TLR4 expression was higher in the I/R injury group than the control and TAK-242 groups (5.189 ± 2.482, 1.186 ± 1.171, and 2.400 ± 0.857, respectively, P < 0.05). NIR-II fluorescence intensity was also higher in the I/R injury group than in the control and TAK-242 groups (86.415 ± 10.955, 38.975 ± 8.619, and 71.977 ± 3.838, respectively; P < 0.05). Thus, anti-TLR4-PbS QDs bound to TLR4 on the cell membranes of intestinal epithelial cells with high specificity in vitro and in vivo. These results indicate that TLR4 promotes intestinal I/R injury during intussusception and that the injury can be noninvasively imaged using TLR4-PbS QDs.

Stable gastric pentadecapeptide BPC 157 in the treatment of colitis and ischemia and reperfusion in rats: New insights

AIM

To provide new insights in treatment of colitis and ischemia and reperfusion in rats using stable gastric pentadecapeptide BPC 157.

METHODS

Medication [BPC 157, L-NAME, L-arginine (alone/combined), saline] was bath at the blood deprived colon segment. During reperfusion, medication was BPC 157 or saline. We recorded (USB microscope camera) vessel presentation through next 15 min of ischemic colitis (IC-rats) or reperfusion (removed ligations) (IC + RL-rats); oxidative stress as MDA (increased (IC- and IC + RL-rats)) and NO levels (decreased (IC-rats); increased (IC + RL-rats)) in colon tissue. IC + OB-rats [IC-rats had additional colon obstruction (OB)] for 3 d (IC + OB-rats), then received BPC 157 bath.

RESULTS

Commonly, in colon segment (25 mm, 2 ligations on left colic artery and vein, 3 arcade vessels within ligated segment), in IC-, IC + RL-, IC + OB-rats, BPC 157 (10 μg/kg) bath (1 mL/rat) increased vessel presentation, inside/outside arcade interconnections quickly reappeared, mucosal folds were preserved and the pale areas were small and markedly reduced. BPC 157 counteracted worsening effects induced by L-NAME (5 mg) and L-arginine (100 mg). MDA- and NO-levels were normal in BPC 157 treated IC-rats and IC + RL-rats. In addition, on day 10, BPC 157-treated IC + OB-rats presented almost completely spared mucosa with very small pale areas and no gross mucosal defects; the treated colon segment was of normal diameter, and only small adhesions were present.

CONCLUSION

BPC 157 is a fundamental treatment that quickly restores blood supply to the ischemically injured area and rapidly activates collaterals. This effect involves the NO system.

Rectification of oxygen transfer through the rat colonic epithelium

AIM

To assess whether higher sensitivity of colonic epithelium to hypoxia at the serosal side is associated with oxygen transfer asymmetry.

METHODS

Rats were fed either with normal chow or a low-sodium diet. Tissues were mounted as flat sheets in a modified, airtight Ussing chamber with oxygen meters in each hemichamber. Mucosal samples from normal diet animals were studied under control conditions, in low-chloride solution and after adding chloride secretion inhibitors and chloride secretagogues. Samples from sodium-deprived rats were studied before and after ouabain addition. In separate experiments, the correlation between short-circuit current and oxygen consumption was analyzed. Finally, hypoxia was induced in one hemichamber to assess the relationship between its oxygen content and the oxygen pressure difference between both hemichambers.

RESULTS

In all studied conditions, oxygen consumption was larger in the serosal hemichamber than in the mucosal one (P = 0.0025 to P < 0.0001). Short-circuit current showed significant correlation with both total oxygen consumption (r = 0.765; P = 0.009) in normoxia and oxygen consumption in the serosal hemichamber (r = 0.754; P = 0.011) during mucosal hypoxia, but not with oxygen consumption in the mucosal hemichamber. When hypoxia was induced in the mucosal hemichamber, an oxygen pressure difference of 13 kPa with the serosal hemichamber was enough to keep its oxygen content constant. However, when hypoxia was induced in the serosal hemichamber, the oxygen pressure difference with the mucosal hemichamber necessary to keep its oxygen content constant was 40 kPa (P < 0.0001).

CONCLUSION

Serosal oxygen supply is more readily available to support short-circuit current. This may be partly due to a rectifying behavior of transepithelial oxygen transfer.

Acute Colonic Pseudo-Obstruction with Feeding Intolerance in Critically Ill Patients: A Study according to Gut Wall Analysis

Objective. To compare the differences between acute colonic pseudo-obstruction (ACPO) with and without acute gut wall thickening. Methods. ACPO patients with feeding tolerance were divided into ACPO with no obvious gut wall thickening (ACPO-NT) group and ACPO with obvious acute gut wall thickening (ACPO-T) group according to computed tomography and abdominal radiographs. Patients' condition, responses to supportive measures, pharmacologic therapy, endoscopic decompression, and surgeries and outcomes were compared. Results. Patients in ACPO-T group had a significantly higher APACHE II (11.82 versus 8.25, p = 0.008) and SOFA scores (6.47 versus 3.54, p < 0.001) and a significantly higher 28-day mortality (17.78% versus 4.16%, p = 0.032) and longer intensive care unit stage (4 versus 16 d, p < 0.001). Patients in ACPO-NT group were more likely to be responsive to supportive treatment (62.50% versus 24.44%, p < 0.001), neostigmine (77.78% versus 17.64%, p < 0.001), and colonoscopic decompression (75% versus 42.86%, p = 0.318) than those in ACPO-T group. Of the patients who underwent ileostomy, 81.25% gained benefits. Conclusions. ACPO patients with gut wall thickening are more severe and are less likely to be responsive to nonsurgical treatment. Ileostomy may be a good option for ACPO patients with gut wall thickening who are irresponsive to nonsurgical treatment.

Colonic ischemia: usual and unusual presentations and their management

PURPOSE OF REVIEW

To provide an update on the epidemiology, pathophysiology, clinical presentation, and management of colonic ischemia.

RECENT FINDINGS

Formerly regarded as a rare cause of lower gastrointestinal hemorrhage, colonic ischemia is now recognized to be the most common manifestation of intestinal vascular compromise. In contrast to ischemic events in the small intestine wherein thrombotic and embolic events predominate, colonic ischemia typically results from a global reduction in blood flow to the colon and no occlusive lesion(s) are evident. Several risk factors for colonic ischemia have been identified and, together with an appropriate clinical presentation and patient demographics, create a context in which the clinician should have a high level of suspicion for its presence. Imaging with computerized tomography, in particular, may be highly supportive of the diagnosis, which where appropriate can be confirmed by colonoscopy and colonic biopsy. For most patients, management is supportive and noninterventional, and the prognosis for recurrence and survival are excellent.

SUMMARY

Colonic ischemia is a common cause of lower abdominal pain and hemorrhage among the elderly typically occurring in the aftermath of an event which led to hypoperfusion of the colon. For most affected individuals the ischemia is reversible and clinical course benign.

Cancer therapy-related complications in the bowel and mesentery: an imaging perspective

Cancer therapy-induced complications in the bowel and mesentery are fairly common. It is important for clinicians to be aware of these complications and the agents most frequently implicated. Cancer therapy is rapidly evolving and often encompasses both classic cytotoxic drugs and newer molecular targeted agents. Drugs from both broad classes can have numerous adverse effects on the bowel and mesentery that can be detected on imaging. These adverse effects include ileus, various forms of enterocolitis, gastrointestinal perforation, pneumatosis intestinalis, secretory diarrhea, and sclerosing mesenteritis. These complications are diverse and range from relatively benign to life threatening. The management is also variable, but many of these conditions are easily controlled and reversed with supportive care and cessation of the particular cancer therapy. The objective of this pictorial essay is to demonstrate some of the more common cancer therapy-induced complications of the bowel and mesentery, with a focus on the radiographic findings.

How to Diagnose and Treat IBD Mimics in the Refractory IBD Patient Who Does Not Have IBD

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract and includes both Crohn's disease and ulcerative colitis. Patients with IBD often present with abdominal pain, diarrhea, and rectal bleeding but may also have a wide variety of other symptoms such as weight loss, fever, nausea, vomiting, and possibly obstruction. Given that the presentation of IBD is not specific, the differential diagnosis is broad and encompasses a wide spectrum of diseases, many of which can mimic and/or even coexist with IBD. It is important for physicians to differentiate symptoms due to refractory IBD from symptoms due to IBD mimics when a patient is not responding to standard IBD treatment. Many of the various IBD mimics include infectious etiologies (viral, bacterial, mycobacterial, fungal, protozoal, and helminthic infections), vascular causes, other immune causes including autoimmune etiologies, drug-induced processes, radiation-induced, and other etiologies such as small intestinal bacterial overgrowth, diverticulitis, and bile acid malabsorption. Thoughtful consideration and evaluation of these potential etiologies through patient history and physical examination, as well as appropriate tests, endoscopic evaluation, and cross-sectional imaging is required to evaluate any patient presenting with symptoms consistent with IBD.

Sonographic and Endoscopic Findings in Cocaine-Induced Ischemic Colitis

Cocaine-induced ischemic colitis is a recognized entity. The diagnosis is based on clinical and endoscopic findings. However, diagnostic imaging is helpful in the evaluation of abdominal symptoms and prior studies have suggested specific sonographic findings in ischemic colitis. We report sonographic and endoscopic images along with abdominal computed tomography in a case of cocaine-induced ischemic colitis.