Acute mesenteric ischaemia and unexpected death

Gastric ischemia as an under-reported cause of death in older people

Acute gastric ischemia is a rare condition due to the rich vascular supply of the stomach. Here we present a case of fatal gastric ischemia associated with bowel ischemia, only diagnosed at autopsy, which was requested for the suspicion of medical liability. A complete post-mortem examination was conducted, along with a macroscopic analysis of the superior mesenteric artery and detailed histological analyses. Past clinical data was also reviewed. The macroscopic blackish discoloration of the stomach and the bowel, coupled with the presence of neutrophils in the mucosa and submucosal non-occlusive thrombi, were consistent with gastric and bowel ischemia, despite the presence of confounding putrefactive changes. The unique aspect of this case resides in the ante-mortem peculiar vascularization of the stomach, supplied by small collateral vessels. No mechanical occlusion was identified, and the cause of the ischemia was deemed as non-occlusive, likely due to systemic hypoperfusion. The analysis of clinical data and documentation of associated comorbidities are strongly recommended, especially when a rare cause of death is suspected. With the aging population, especially among women, and the prevalence of risk factors, the forensic pathologist could increasingly encounter rare cases of gastric ischemia.

FAR Ratio as Prognostic Biomarker in AMI

Acute mesenteric ischemia (AMI) is a vascular emergency resulting from decreased blood flow caused by the occlusion of the mesenteric vessels, hypoperfusion, or vasospasm. This study aimed to investigate the prognostic value of the fibrinogen-to-albumin (FAR) ratio in patients with acute mesenteric ischemia. A total of 91 patients were enrolled in the study. Patients' demographics such as age and gender, pre- and postoperative hemoglobin, CRP, white blood cell (WBC), neutrophils, preoperative lymphocyte, alanine transaminase (ALT), aspartate transaminase (AST), thrombocytes, and postoperative D-dimer values were recorded. In addition, pre- and postoperative fibrinogen and albumin levels were recorded, and FAR was calculated. Patients were divided into two groups, survivors and non-survivors. The mean pre- and postoperative fibrinogen levels were statistically significantly higher in the non-survivor group than in the survivor group (p < 0.001). The mean pre- and postoperative albumin levels were significantly lower in the non-survivors than in the survivors (p = 0.059, p < 0.001; respectively). The mean pre- and postoperative FAR ratios were considerably higher in the non-survivor than in the survivor groups (p < 0.001). The change between pre- and postoperative fibrinogen, albumin, and FAR values was statistically significant between the non-survivors and the survivors (for all, p < 0.05). The preoperative and postoperative fibrinogen levels were significantly lower, and albumin levels were significantly higher in the survivor compared to the non-survivor patients with AMI. Furthermore, the preoperative and postoperative FAR ratio was significantly higher in the non-survivors. The FAR ratio may be a valuable prognostic biomarker for patients with AMI.

Anti-inflammatory and antioxidant effects of the nanocomposite Fullerol decrease the severity of intestinal inflammation induced by gut ischemia and reperfusion

Intestinal ischemia is a vascular emergency that arises when blood flow to the intestine is compromised. Reperfusion is necessary to restore intestinal function but might lead to local and systemic inflammatory responses and bacterial translocation, with consequent multiple organ dysfunction syndrome (MODS). During reperfusion occurs production of reactive oxygen species. These species contribute to intestinal injury through direct toxicity or activation of inflammatory pathways. Fullerol is a nanacomposite which has been shown to act as reactive oxygen species and reactive nitrogen species (RNS) scavengers. Thus, our aim was to evaluate whether Fullerol confer anti-inflammatory activity during intestinal ischemia and reperfusion (IIR). Intestinal ischemia was induced by total occlusion of the superior mesenteric artery. Groups were treated with vehicle or Fullerol 10 min before reperfusion. Mice were euthanized after 6 h of reperfusion, and small intestines were collected for evaluation of plasma extravasation, leukocyte influx, cytokine production and histological damage. Bacterial translocation to the peritoneal cavity and reactive oxygen and nitrogen species production by lamina propria cells were also evaluated. Our results showed that treatment with Fullerol inhibited bacterial translocation to the peritoneal cavity, delayed and decreased the lethality rates and diminished neutrophil influx and intestinal injury induced by IIR. Reduced severity of reperfusion injury in Fullerol-treated mice was associated with blunted reactive oxygen and nitrogen species production in leukocytes isolated from gut lamina propria and decreased production of pro-inflammatory mediators. Thus, the present study shows that Fullerol is a potential therapy to treat inflammatory bowel disorders associated with bacterial translocation, such as IIR.

Ischaemic postconditioning reduces apoptosis in experimental jejunal ischaemia in horses

BACKGROUND

Ischaemic postconditioning (IPoC) refers to brief periods of reocclusion of blood supply following an ischaemic event. This has been shown to ameliorate ischaemia reperfusion injury in different tissues, and it may represent a feasible therapeutic strategy for ischaemia reperfusion injury following strangulating small intestinal lesions in horses. The objective of this study was to assess the degree cell death, inflammation, oxidative stress, and heat shock response in an equine experimental jejunal ischaemia model with and without IPoC.

METHODS

In this randomized, controlled, experimental in vivo study, 14 horses were evenly assigned to a control group and a group subjected to IPoC. Under general anaesthesia, segmental ischaemia with arterial and venous occlusion was induced in 1.5 m jejunum. Following ischaemia, the mesenteric vessels were repeatedly re-occluded in group IPoC only. Full thickness intestinal samples and blood samples were taken at the end of the pre-ischaemia period, after ischaemia, and after 120 min of reperfusion. Immunohistochemical staining or enzymatic assays were performed to determine the selected variables.

RESULTS

The mucosal cleaved-caspase-3 and TUNEL cell counts were significantly increased after reperfusion in the control group only. The cleaved-caspase-3 cell count was significantly lower in group IPoC after reperfusion compared to the control group. After reperfusion, the tissue myeloperoxidase activity and the calprotectin positive cell counts in the mucosa were increased in both groups, and only group IPoC showed a significant increase in the serosa. Tissue malondialdehyde and superoxide dismutase as well as blood lactate levels showed significant progression during ischaemia or reperfusion. The nuclear immunoreactivity of Heat shock protein-70 increased significantly during reperfusion. None of these variables differed between the groups. The neuronal cell counts in the myenteric plexus ganglia were not affected by the ischaemia model.

CONCLUSIONS

A reduced apoptotic cell count was found in the group subjected to IPoC. None of the other tested variables were significantly affected by IPoC. Therefore, the clinical relevance and possible protective mechanism of IPoC in equine intestinal ischaemia remains unclear. Further research on the mechanism of action and its effect in clinical cases of strangulating colic is needed.

Causes of sudden death related to oesophageal carcinoma

Two cases of recently diagnosed oesophageal squamous-cell carcinomas in men, both aged 72 years, are reported that resulted in rapid clinical deterioration and death from upper-airway occlusion and haemorrhage, respectively. In the first case, direct growth of the tumour from metastatic deposits in the paratracheal lymph nodes through the wall of the trachea resulted in lethal acute airway occlusion. In the second case, local extension of the tumour through the wall of the oesophagus into the adjacent aorta resulted in an aorto-oesophageal fistula which led to catastrophic and fatal haemorrhage. Although rare, oesophageal squamous-cell carcinomas may cause unexpected death due to quite different mechanisms, and result in the need for a detailed medico-legal assessment.

The HO-1-expressing bone mesenchymal stem cells protects intestine from ischemia and reperfusion injury

BACKGROUND

Bone mesenchymal stromal cells (BMSC) showed protective potential against intestinal ischemia. Oxygenase-1(HO-1) could alleviate oxidative stress. In the present study, we constructed HO-1-expressing BMSC and detected the effects of it on survival, intestinal injury and inflammation following intestinal ischemia and reperfusion injury (I/R).

METHODS

In this experiment, eighty adult male mice were divided into Sham, I/R, I/R + BMSC, I/R + BMSC/HO-1 groups. Mice were anesthetized and intestinal I/R model were established by temporarily occluding the superior mesenteric artery for 60 min with a non-crushing clamp. Following ischemia, the clamp was removed and the intestines were allowed for reperfusion. Prior to abdominal closure, BMSC/ HO-1 (2 × 10⁶ cells) or BMSC (2 × 10⁶ cells) were injected into the peritoneum of I/R mice respectively. Mice were allowed to recover for 24 h and then survival rate, intestinal injury and inflammation were determined. Reactive oxygen species (ROS) was assayed by fluorescent probe. TNFα and IL-6 were assayed by ELISA.

RESULTS

BMSC/HO-1 increased seven day survival rate, improved intestinal injury and down-regulated inflammation after intestinal I/R when compared with sole BMSC (p < 0.05 respectively). Multiple pro-inflammatory media were also decreased following application of BMSC/HO-1, when compared with sole BMSC (p < 0.05) respectively, suggesting that BMSC /HO-1 had a better protection to intestinal I/R than BMSC therapy.

CONCLUSION

Administration of BMSC/HO-1 following intestinal I/R, significantly improved intestinal I/R by limiting intestinal damage and inflammation.

Resveratrol Suppresses Gut-Derived NLRP3 Inflammasome Partly through Stabilizing Mast Cells in a Rat Model

Background

Inflammatory responses induced by intestinal ischemia-reperfusion (IIR) lead to serious systemic organ dysfunction and pose a challenge for current treatment. This study aimed at investigating the effects of resveratrol on IIR-induced intestinal injury and its influence on mast cells (MCs) in rats.

Methods

Rats subjected to intestinal ischemia for 60 min and 4 h of IIR were investigated. Animals were randomly divided into five groups (n = 8 per group): sham, IIR, resveratrol (RESV, 15 mg/kg/day for 5 days before operation) + IIR, cromolyn sodium (CS, MC membrane stabilizer) + IIR, and RESV + compound 48/80 (CP, MC agonist) + IIR.

Results

Intestinal injury and increased proinflammatory cytokines including tumor necrosis factor-α, interleukin-1β, and interleukin-18 were observed in the IIR group. Intestinal MC-related tryptase and β-hexosaminidase levels were also increased after rats were subjected to IIR accompanied by activation of NLRP3 inflammasomes. Interestingly, pretreatment with resveratrol significantly suppressed the activities of proinflammatory cytokines and attenuated intestinal injury. Resveratrol also reduced MC and NLRP3 inflammasome activation, which was consistent with the effects of cromolyn sodium. However, the protective effects of resveratrol were reversed by the MC agonist compound 48/80.

Conclusions

In summary, these findings reveal that resveratrol suppressed IIR injury by stabilizing MCs, preventing them from degranulation, accompanied with intestinal mucosa NLRP3 inflammasome inhibition and intestinal epithelial cell apoptosis reduction.

Activated protein C resistance associated with lupus anticoagulants is a high risk in acute mesenteric venous thrombosis

BACKGROUND

Acute mesenteric venous thrombosis (AMVT) is one of those diseases that cannot be diagnosed by specific symptoms and signs. A high misdiagnosis rate makes AMVT a final diagnosis established by exploratory laparotomy or forensic examinations earlier, during the period when computed tomography was not as efficient as it is now. The main motivation of our research was to improve the diagnosis and treatment by finding the relationship among activated protein C (APC) resistance, antiphospholipid antibodies, and AMVT in the Chinese Han population.

METHODS

APC resistance was tested by activated partial thromboplastin time method in 70 AMVT patients and 75 healthy adult volunteers that excluded hypercoagulable states. Factor V Leiden mutation was analyzed by polymerase chain reaction with restriction fragment length polymorphism. Anticardiolipin antibodies (aCLs) were tested by enzyme-linked immunosorbent assay. A sensitive activated partial thromboplastin time-lupus anticoagulant (LA) test was used according to the guidelines.

RESULTS

Only two samples had factor V Leiden mutation and were excluded. Twenty-one (30.9%) of the 68 AMVT patients had APC resistance. The rate of aCLs positive in AMVT group (13.2%) was significantly increased compared with control group (1.33%; P = .014). The LA-positive rate is significantly different between the AMVT and control group. Among LA-positive patients, the number of APC resistance was much higher than LA-negative patients (P = .000), but aCLs do not have an increased predisposition to APC resistance (P = .85).

CONCLUSIONS

APC resistance associated with LAs is a high risk in AMVT. The way aCL may affect the process of AMVT is not the same as with LA.

Computed tomography findings of pneumatosis and portomesenteric venous gas in acute bowel ischemia

AIM: To use more representative sample size to evaluate whether computed tomography (CT) scan evidence of the concomitant presence of pneumatosis and portomesenteric venous gas is a predictor of transmural bowel necrosis.

METHODS: Data from 208 patients who were referred for a diagnosis of bowel ischemia were retrospectively reviewed. Only patients who underwent a surgical intervention following a diagnosis of bowel ischemia who also had a post-operative histological confirmation of such a diagnosis were included. Patients were split into two groups according to the presence of histological evidence of transmural bowel ischemia (case group) or partial bowel ischemia (control group). CT images were reviewed for findings of ischemia, including mural thickening, pneumatosis, bowel distension, portomesenteric venous gas and arterial or venous thrombi.

RESULTS: A total of 248 subjects who underwent surgery for bowel ischemia were identified. Among the 208 subjects enrolled in our study, transmural bowel necrosis was identified in 121 subjects (case group), and partial bowel necrosis was identified in 87 subjects (control group). Based on CT findings, including mural thickening, bowel distension, pneumatosis, pneumatosis plus portomesenteric venous gas and presence of thrombi or emboli, there were no significant differences between the case and control groups. The concomitant presence of pneumatosis and porto-mesenteric venous gas showed an odds ratio of 1.95 (95%CI: 0.491-7.775, P = 0.342) for the presence of transmural necrosis. The presence of pneumatosis plus porto-mesenteric venous gas exhibited good specificity (83%) but low sensitivity (17%) in the identification of transmural bowel infarction. Accordingly, the positive and negative predictive values were 60% and 17%, respectively.

CONCLUSION: Although pneumatosis plus porto-mesenteric venous gas is associated with bowel ischemia, we have demonstrated that their co-occurrence cannot be used as diagnostic signs of transmural necrosis.