Probabilistic Prediction of Gastrointestinal Ischemia after Cardiothoracic Surgery.

BACKGROUND: Gastrointestinal ischemia (GIisch) is challenging to diagnose in patients after cardiothoracic surgery. Computed tomography angiography (CTA) carries substantial false-negative and false-positive rates. The aim of the study was to evaluate if a combination of readily available variables improves the diagnosis of GIisch after cardiothoracic surgery. METHODS: This retrospective study included patients receiving intensive care after cardiothoracic surgery. GIisch was confirmed by surgical and/or endoscopic findings. A GIisch prediction score was developed using the Spiegelhalter-Knill-Jones system in a training cohort then tested in a validation cohort (patients without obvious signs of GIisch on CTA). RESULTS: The training cohort comprised 125 consecutive patients with suspected GIisch in 2008 to 2019, including 85 with confirmed GIisch. CTA, performed in 92 patients, had a high false-negative rate of 17/60 (28%) and a lower false-positive rate of 7/32 (22%). The score included cardiopulmonary bypass, negatively associated with GIisch, and six variables positively associated with GIisch: intraoperative mean arterial pressure < 50 mm Hg, aspartate aminotransferase > 15 N, lactate increase in 24 hour > 20%, and 3 CTA findings, namely, bowel dilation, bowel wall thickening, and mesenteric vasoconstriction. The area under the receiver operating characteristic was 0.82 (95% confidence interval [CI], 0.51-0.93) in the training cohort and 0.82 (95% CI, 0.68-0.96) in the validation cohort (n = 34 patients). Reliability of the predicted probabilities was greatest for probabilities ≤ 30% or ≥ 70%. CONCLUSION: In patients receiving intensive care after cardiothoracic surgery, GIisch cannot be ruled out based solely on CTA findings. A scoring system combining CTA findings with other variables may improve the diagnosis of GIisch in this population.

Gastrointestinal angiodysplasia in heart failure and during CF LVAD support.

Angiodysplasias (AGD) are common sites of bleeding in the gastrointestinal (GI) tract after Continuous Flow Left Ventricular Assist Device (CF-LVAD) implantation. We sought to investigate whether AGDs are formed as a result of LVAD physiology or preexist as a consequence of heart failure. Thirty-six subjects with HF reduced EF (HFrEF) underwent video capsule endoscopy (VCE) to assess for the presence of AGD. Fifty-three subjects without HF who underwent VCE for a nonbleeding indication formed a control group. The prevalence of AGD was significantly higher in the HFrEF compared to the non-HF controls (50% vs 13%, p = 0.0002). This association persisted after controlling for age and comorbidities. Within the HFrEF cohort, higher Ang2, NT-proBNP and BUN were associated with the presence of AGD. AGD in the GI tract are associated with HFrEF. This is the first description of a new pathology associated with HFrEF and adds to our understanding of CF LVAD associated GI bleeding.

Sub-therapeutic vasopressin but not therapeutic vasopressin improves gastrointestinal microcirculation in septic rats: A randomized, placebo-controlled, blinded trial.

INTRODUCTION: Sepsis impairs gastrointestinal microcirculation and it is hypothesized that this might increase patient's mortality. Sub-therapeutic vasopressin improves gastric microcirculation under physiologic conditions whereas a therapeutic dosing regimen seems to be rather detrimental. However, the effects of sub-therapeutic vasopressin on gastrointestinal microcirculation in sepsis are largely unknown. Therefore, we conducted this trial to investigate the effect of sub-therapeutic as well as therapeutic vasopressin on gastrointestinal microcirculation in sepsis. METHODS: 40 male Wistar rats were randomized into 4 groups. Colon ascendens stent peritonitis (CASP)-surgery was performed to establish mild or moderate sepsis. 24 hours after surgery, animals received either vasopressin with increasing dosages every 30 min (6.75, 13.5 (sub-therapeutic), 27 mU · kg-1 · h-1 (therapeutic)) or vehicle. Microcirculatory oxygenation (µHBO2) of the colon was recorded for 90 min using tissue reflectance spectrophotometry. Intestinal microcirculatory perfusion (total vessel density (TVD; mm/mm2) and perfused vessel density (PVD; mm/mm2)) were measured using incident dark field-Imaging at baseline and after 60 min. RESULTS: In mild as well as in moderate septic animals with vehicle-infusion intestinal µHbO2, TVD and PVD remained constant. In contrast, in moderate sepsis, sub-therapeutic vasopressin with 13.5 mU · kg-1 · h-1 elevated intestinal µHBO2 (+ 6.1 ± 5.3%; p < 0.05 vs. baseline) and TVD (+ 5.2 ± 3.0 mm/mm2; p < 0.05 vs. baseline). µHBO2, TVD and PVD were significantly increased compared to moderate sepsis alone. However, therapeutic vasopressin did not change intestinal microcirculation. In mild septic animals sub-therapeutic as well as therapeutic vasopressin had no relevant effect on gastrointestinal microcirculation. Systemic blood pressure remained constant in all groups. CONCLUSION: Sub-therapeutic vasopressin improves gastrointestinal microcirculatory oxygenation in moderate sepsis without altering systemic blood pressure. This protective effect seems to be mediated by an enhanced microcirculatory perfusion and thereby increased oxygen supply. In contrast, therapeutic vasopressin did not show this beneficial effect.

Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) in Physiological and Pathological Processes within the Gastrointestinal Tract: A Review.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide widely distributed in the central nervous system (CNS) and many peripheral organs, such as the digestive tract, endocrine, reproductive and respiratory systems, where it plays different regulatory functions and exerts a cytoprotective effect. The multifarious physiological effects of PACAP are mediated through binding to different G protein-coupled receptors, including PAC1 (PAC1-R), VPAC1 (VPAC1-R) and VPAC2 (VPAC2-R) receptors. In the gastrointestinal (GI) tract, PACAP plays an important regulatory function. PACAP stimulates the secretion of digestive juices and hormone release, regulates smooth muscle contraction, local blood flow, cell migration and proliferation. Additionally, there are many reports confirming the involvement of PACAP in pathological processes within the GI tract, including inflammatory states, neuronal injury, diabetes, intoxication and neoplastic processes. The purpose of this review is to summarize the distribution and pleiotropic action of PACAP in the control of GI tract function and its cytoprotective effect in the course of GI tract disorders.

Differential expression of motilin receptors on the endothelium of dog gastrointestinal arteries and motilin-induced motilin receptor dependent relaxation of corresponding arteries.

BACKGROUND: Motilin's role in the regulation of vascular tone and hemodynamic besides gastrointestinal motility is concerned. This study aimed to investigate the expression of motilin receptors in gastrointestinal arteries and motilin-induced relaxation. MATERIAL AND METHODS: The expression of motilin receptors in the left gastric artery (LGA), superior mesenteric artery (SMA), and inferior mesenteric artery (IMA) of adult dogs (1.5-5 years old) were analyzed by immunochemistry, RT-PCR, and western blotting. Motilin's effects on the gastrointestinal arteries were evaluated in a multi-wire myograph system. RESULTS: Immunohistochemical staining showed that motilin receptor was expressed on the membranes of endothelial cells with the fluorescence intensity LGA > SMA > IMA (P < 0.01). The motilin receptor's mRNA and protein expression levels shared the same distribution patterns as it in fluorescence intensity (P < 0.01). In isolated LGA preparations precontracted with U46619 (a thromboxaneA2 analog), motilin induced a concentration-dependent relaxation, and the EC50 was 8.8 × 10-8 ± 0.9 × 10-8 M. Motilin-induced relaxation on the three arteries also shared the same pattern as it in fluorescence intensity (P < 0.01) and inhibited by denuded-endothelium and GM-109 (a motilin receptor antagonist) but not by atropine (a muscarinic receptor antagonist). CONCLUSIONS: Motilin receptors are expressed differentially on the membranes of endothelial cells in dog gastrointestinal arteries with a significantly high expression in the LGA. Motilin-induced relaxation is endothelium- and motilin receptor-dependent. The motilin receptor expressed on the endothelial cell membrane of the LGA is the molecular basis for motilin regulating gastric blood flow under physiological conditions in dogs.

Hemodynamic Influences on Mesenteric Blood Flow in Shock Conditions.

The gastrointestinal (GI) system, is most vulnerable to hypoperfusion among the splanchnic organs. Disturbed perfusion of the mesenteric area may lead to GI dysfunction, cause further injury to the patients and even vital outcomes. However, due to the limitation of detection methods, the hemodynamic influences on mesenteric blood flow in clinical practice are not fully understood. By elucidating the underlying mechanisms, we may be able to recognize disturbed GI perfusion and eventually GI dysfunction at an early phase. Thus, in this review, we will focus on situations where mesenteric blood flow is disturbed due to hemodynamic causes in shock conditions, and the present research status will be discussed. English language articles published before 2020 were identified through a computerized PubMed search using the terms "mesenteric, gastrointestinal, intestinal, splanchnic, blood flow, perfusion" and the cofactors. Relevant publications were retrieved and scanned for additional sources. There were few clinical trials focusing on mesenteric blood flow in shock patients. Most were animal experiments. Based on the best current evidence from these sources, we described the major influences on mesenteric blood flow in the context of physiologic accommodation, disease-related effects and the consequences of medical interventions related to shock conditions. During circulatory shock, sepsis, and medical interventions related to shock treatment, mesenteric blood flow changes and shows different features. We need to carefully consider these issues when making medical decisions, and more work needs to be done on early detection of GI hypoperfusion and its accurate correlation with GI dysfunction.

Sonography of pediatric gastrointestinal venous malformations.

Gastrointestinal (GI) venous malformations are extremely rare. Such malformations present in the pediatric age group and can occur anywhere in the digestive tract (esophagus, stomach, small or large intestine, anus, and mesentery). We present the sonographic findings of three cases of pediatric GI venous malformation. Sonography is an important diagnostic method in pediatric GI venous malformations.

Outcomes in Severe Upper GI Hemorrhage from Dieulafoy's Lesion with Monitoring of Arterial Blood Flow.

BACKGROUND: Dieulafoy's lesion (DL) is a rare but increasingly recognized cause of severe upper GI hemorrhage (SUGIH). There is little consensus regarding the endoscopic approach to management of bleeding from DL. AIMS: Our purposes were to compare 30-day outcomes of patients with SUGIH from DL with Doppler endoscopic probe (DEP) monitoring of blood flow and guided treatment versus standard visually guided hemostasis (VG). METHODS: Eighty-two consecutive DL patients with SUGIH were identified in a large CURE Hemostasis database from previous prospective cohort studies and two recent RCTs at two university-based medical centers. 30-day outcomes including rebleeding, surgery, angiography, death, and severe medical complications were compared between the two treatment groups. RESULTS: 40.2% of DL bleeds occurred in inpatients. 43.9% of patients had cardiovascular disease, and 48.7% were taking medications associated with bleeding. For the entire cohort, 41.3% (26/63) of patients treated with VG had a composite 30-day outcome as compared to 10.5% (2/19) of patients treated with DEP (p = 0.017). Rebleeding occurred within 30 days in 33.3% and 10.5% of those treated with VG and DEP, respectively (p = 0.051). After propensity score matching, the adjusted 30-day composite outcome occurred in 39.0% in the VG group compared to 2.6% in the DEP group (p < 0.001). Adjusted 30-day rebleeding occurred in 25.3% in the VG group versus 2.6% in the DEP group (p < 0.001). DISCUSSION: DL patients with SUGIH were frequently inpatients and had severe cardiovascular comorbidities and recurrent bleeding. Lesion arterial blood flow monitoring and obliteration are an effective way to treat bleeding from DL which reduces negative 30-day clinical outcomes.

Cross-Sectional Imaging Evaluation of Vascular Lesions in the Gastrointestinal Tract and Mesentery.

Gastrointestinal (GI) tract and mesenteric vascular lesions can have various clinical presentations, of which GI bleeding is the most common. This collection of pathology is highly variable in etiology ranging from occlusive disease to vascular malformations to trauma to neoplasms which makes for a challenging workup and diagnosis. The advent of multiple imaging modalities and endoscopic techniques makes the diagnosis of these lesions more achievable, and familiarity with their various imaging findings can have a significant impact on patient management. In this article, we review the gamut of GI tract and mesenteric vascular lesions and their associated imaging findings.

The characteristics of video capsule endoscopy in pediatric Henoch-Schönlein purpura with gastrointestinal symptoms.

BACKGROUND: Henoch-Schönlein purpura (HSP) is a systemic small-vessel vasculitis also named IgA vasculitis that commonly affects the gastrointestinal tract. The video capsule endoscopy (VCE) characteristics of pediatric HSP patients are rarely reported. METHODS: Patients diagnosed with HSP and analyzed by VCE examination at our hospital from February 2010 to January 2019 are enrolled. The clinical features, laboratory findings, and the characteristics of VCE findings are studied. RESULTS: There are 30 patients enrolled in this investigation from February 2010 to January 2020. The mean age of these patients is 96.9 ± 35.8 months, and the most frequent finding of VCE is mucosal erosion, which account for 79.3% of the patients, and followed by mucosal erythema or petechia accounted for 69% of the patients. Regarding the disease location detected by endoscopy, jejunum is the most common involved part of the gastrointestinal tract in pediatric HSP patients. All the patients had the jejunum involved except in one patient the VCE did not pass through the pylorus. One third of the patients involved the descending portion of duodenum. No side effect is observed in this study. CONCLUSIONS: VCE may be an excellent adjust tool for evaluation of the gastrointestinal tract in children with abdominal symptoms without typical purpura in suspected pediatric HSP patients. VCE appears to be superior to esophagogastroduodenoscopy in detecting small intestinal lesions of HSP and has an excellent safety profile.

Defective development and microcirculation of intestine in Npr2 mutant mice.

Intractable gastrointestinal (GI) diseases often develop during infancy. Our group previously reported that natriuretic peptide receptor B (NPR-B)-deficient Npr2slw/slw mice exhibit severe intestinal dysfunction, such as stenosis and distention, which resembles the dysfunction observed in Hirschsprung's disease-allied disorders. However, the root cause of intestinal dysfunction and the detailed of pathophysiological condition in the intestine are not yet clear. Here, we report that the intestine of preweaning Npr2slw/slw mice showed bloodless blood vessels, and nodes were found in the lymphatic vessel. Additionally, the lacteals, smooth muscle, blood vessel, and nerves were barely observed in the villi of preweaning Npr2slw/slw mice. Moreover, intramuscular interstitial cells of Cajal (ICC-IM) were clearly reduced. In contrast, villi and ICC-IM were developed normally in surviving adult Npr2slw/slw mice. However, adult Npr2slw/slw mice exhibited partially hypoplastic blood vessels and an atrophied enteric nervous. Furthermore, adult Npr2slw/slw mice showed markedly reduced white adipose tissue. These findings suggest that the cause of GI dysfunction in preweaning Npr2slw/slw mice is attributed to defective intestinal development with microcirculation disorder. Thus, it is suggested that NPR-B signaling is involved in intestinal development and control of microcirculation and fat metabolism. This report provides new insights into intractable GI diseases, obesity, and NPR-B signaling.

Berberine reduces gut-vascular barrier permeability via modulation of ApoM/S1P pathway in a model of polymicrobial sepsis.

AIMS: The hyperpermeability of gut-vascular barrier (GVB) plays a role in gut-derived sepsis. The goal of this study was to evaluate if berberine might improve hepatic apolipoprotein M (ApoM) generation and raise plasma ApoM level to protect the compromised GVB. MATERIALS AND METHODS: The compromised GVB was induced by sepsis. Hepatic ApoM mRNA and phosphoenolpyruvate carboxykinase (PEPCK) mRNA and plasma ApoM level were assayed by qRT-PCR and ELISA, respectively. The permeability of intestinal capillary in vivo and of rat intestinal microvascular endothelial cells (RIMECs) in vitro was assayed by FITC-dextran. The blood glucose was detected by a glucometer. Plasma insulin, TNF-α and IL-1ß were assayed by ELISA. The plasmalemma vesicle-associated protein-1 (PV1), ß-catenin and occludin in RIMECs were assayed by Western blot. KEY FINDINGS: Sepsis decreased hepatic ApoM mRNA and plasma ApoM level, but raised hepatic PEPCK mRNA and plasma glucose, insulin, TNF-α, and IL-1ß levels. The increased vascular endothelial permeability was abrogated by recombinant rat ApoM in vivo or ApoM-bound S1P in vitro. ApoM-bound S1P decreased PV1 but increased occludin and ß-catenin expression in LPS-treated RIMECs. Berberine in a dose-dependent manner raised hepatic ApoM mRNA and plasma ApoM level, but decreased septic hyperglycemia, insulin resistance and plasma TNF-α and IL-1ß levels. Berberine reduced sepsis-induced PEPCK and TLR4 mRNA overexpression in the liver. SIGNIFICANCE: This study demonstrated berberine inhibited TLR4-mediated hyperglycemia, insulin resistance and proinflammatory molecule production, thereby increasing ApoM gene expression and plasma ApoM. Berberine protected the damaged GVB via modulation of ApoM/S1P pathway.

Intra-abdominal hypertension as a trigger of "gut failure" in SARS-CoV-2 infection: Effect of open abdomen (OA) and negative pressure therapy (NPT) on respiratory and gastrointestinal (GI) function.

COVID-19 gastrointestinal manifestations could be attributed to SARS-CoV-2-induced small vessel thrombosis. OA with NPT treatment may have a role in optimization of bowel microcirculation and in the reduction of the endothelial and the systemic cytokine-related damage, improving also respiratory function.

A combination of single-balloon enteroscopy-assisted laparoscopy and endoscopic mucosal resection for treating gastrointestinal venous malformations in blue rubber bleb nevus syndrome: a case report.

BACKGROUND: Blue rubber bleb nevus syndrome (BRBNS) is a rare congenital disease characterized by multifocal venous malformations. It remains a considerable challenge in treating the gastrointestinal (GI) venous malformations due to multiple lesions throughout the GI tract, and the likelihood of recurrence. We report a case study of BRBNS in the GI tract, in which GI venous malformations and related GI bleeding were successfully treated with a combination of multiple endoscopic procedures. CASE PRESENTATION: A 17-year-old man was admitted to our hospital for dizziness and hypodynamia. The symptoms persisted for nearly 1 year. The laboratory tests revealed iron-deficiency anemia with abnormally low hemoglobin (Hb), and a strong positive fecal occult blood test. A total of four hemangiomas were detected: one in the stomach, one in the descending colon, and two in the small intestines with a high risk of hemorrhage. Under gastroendoscopy, enteroscopy, and video capsule endoscopy (VCE) throughout the GI tract, the patient underwent surgical treatment. Endoscopic mucosal resection was initially performed in the stomach and colon, and the lesions in the small intestine were resected with laparoscopy auxiliaried by single-balloon enteroscopy (SBE), during which SBE assisted in identifying the lesions. The patient well-tolerated the procedures, and had a favorable prognosis. CONCLUSION: The combination of single-balloon enteroscopy-assisted laparoscopy and endoscopic mucosal resection was effective for the present case, which could be considered for patients with similar clinical conditions.

Hypocomplementemic urticarial vasculitis syndrome with gastrointestinal vasculitis and crescentic membranoproliferative glomerulonephritis without immune complex deposits.

Hypocomplementemic urticarial vasculitis syndrome (HUVS) is a small vessel vasculitis characterized by hypocomplementemia and urticaria-like exanthema. Some cases also display abdominal pain and membranoproliferative glomerulonephritis (MPGN) with immune complex deposits. We treated a case of HUVS with biopsy-proven gastrointestinal vasculitis and atypical histological findings in a kidney biopsy. The 36-year-old Japanese man, who was previously diagnosed with diffuse panbronchiolitis, visited our hospital due to transient urticaria-like exanthema and rapid deterioration of kidney function. On admission, the skin lesion was found to be only pigmentation, showing no vasculitis by skin biopsy. In laboratory findings, renal dysfunction with hematuria and proteinuria and hypocomplementemia were observed. Gastrointestinal vasculitis was proven by endoscopy and biopsy of the mucosa. Kidney biopsy revealed MPGN with crescents. No immune complex deposits were observed by immunofluorescence or electron microscopy. Additional examination revealed high titers of anti-C1q antibody. The patient was diagnosed with HUVS and treated with corticosteroids and plasma exchange. Although renal function and gastrointestinal vasculitis partially improved, infectious pneumonia frequently recurred. His renal dysfunction began to progress again and reached end-stage kidney disease. This is the first case of HUVS with biopsy-proven gastrointestinal vasculitis and MPGN without immune complex deposits. Notably, in some case of HUVS, anti-C1q antibody may activate the alternative complement pathway without immune complex deposits, resulting in renal injury.

Exogenous vasopressin dose-dependently modulates gastric microcirculatory oxygenation in dogs via V1A receptor.

BACKGROUND: Hypercapnia improves gastric microcirculatory oxygenation (µHbO2) and increases vasopressin plasma levels, whereas V1A receptor blockade abolishes the increase of µHbO2. The aim of this study was to evaluate the effect of exogenous vasopressin (AVP) in increasing doses on microcirculatory perfusion and oxygenation and systemic hemodynamic variables. Furthermore, we evaluated the role of the vasopressin V1A receptor in mediating the effects. METHODS: In repetitive experiments, six anesthetized dogs received a selective vasopressin V1A receptor inhibitor ([Pmp1, Tyr (Me)2]-Arg8-Vasopressin) or sodium chloride (control groups). Thereafter, a continuous infusion of AVP was started with dose escalation every 30 min (0.001 ng/kg/min-1 ng/kg/min). Microcirculatory variables of the oral and gastric mucosa were measured with reflectance spectrometry, laser Doppler flowmetry, and incident dark field imaging. Transpulmonary thermodilution was used to measure systemic hemodynamic variables. AVP plasma concentrations were measured during baseline conditions and 30 min after each dose escalation. RESULTS: During control conditions, gastric µHbO2 did not change during the course of experiments. Infusion of 0.001 ng/kg/min and 0.01 ng/kg/min AVP increased gastric µHbO2 to 87 ± 4% and 87 ± 6%, respectively, compared to baseline values (80 ± 7%), whereas application of 1 ng/kg/min AVP strongly reduced gastric µHbO2 (59 ± 16%). V1A receptor blockade prior to AVP treatment abolished these effects on µHbO2. AVP dose-dependently enhanced systemic vascular resistance (SVR) and decreased cardiac output (CO). After prior V1A receptor blockade, SVR was reduced and CO increased (0.1 ng/kg/min + 1 ng/kg/min AVP). CONCLUSIONS: Exogenous AVP dose-dependently modulates gastric µHbO2, with an increased µHbO2 with ultra-low dose AVP. The effects of AVP on µHbO2 are abolished by V1A receptor inhibition. These effects are independent of a modulation of systemic hemodynamic variables.

A Differential Approach to Form and Site of Peptic Ulcer.

The structural organization of intestinal blood flow is such as to allow for intramural collateral flow. Redistribution phenomena due to different local metabolic demands may lead to an impaired perfusion of parts of the intestinal wall which will display a characteristic pattern. Based on Ohm's and Kirchhoff's laws, a differential analysis of the gastric vascular bed bridges the gap between basic physiological concepts and traditional anatomical, pathological and clinical knowledge. An ulcer of the intestinal wall becomes understandable as a non-occlusive infarct based on a supply/demand conflict in an anisotropic structure as it can be found in the upper and lower gastrointestinal tract of man.