Impaired intestinal mucosal barrier upon ischemia-reperfusion: "patching holes in the shield with a simple surgical method"

Impairment of Mesenteric Perfusion as a Marker of Major Bleeding in Trauma Patients

The majority of potentially preventable mortality in trauma patients is related to bleeding; therefore, early recognition and effective treatment of hemorrhagic shock impose a cardinal challenge for trauma teams worldwide. The reduction in mesenteric perfusion (MP) is among the first compensatory responses to blood loss; however, there is no adequate tool for splanchnic hemodynamic monitoring in emergency patient care. In this narrative review, (i) methods based on flowmetry, CT imaging, video microscopy (VM), measurement of laboratory markers, spectroscopy, and tissue capnometry were critically analyzed with respect to their accessibility, and applicability, sensitivity, and specificity. (ii) Then, we demonstrated that derangement of MP is a promising diagnostic indicator of blood loss. (iii) Finally, we discussed a new diagnostic method for the evaluation of hemorrhage based on exhaled methane (CH₄) measurement. Conclusions: Monitoring the MP is a feasible option for the evaluation of blood loss. There are a wide range of experimentally used methodologies; however, due to their practical limitations, only a fraction of them could be integrated into routine emergency trauma care. According to our comprehensive review, breath analysis, including exhaled CH₄ measurement, would provide the possibility for continuous, non-invasive monitoring of blood loss.

Probiotics ameliorate renal ischemia-reperfusion injury by modulating the phenotype of macrophages through the IL-10/GSK-3β/PTEN signaling pathway

After renal ischemic reperfusion injury, a series of pathological changes, such as impaired intestinal barrier function, intestinal flora, and endotoxin translocation, are caused by intestinal ischemia and hypoxia, which then trigger systemic inflammatory responses and affect the condition and prognosis of the patients. In this study, a rat model of ischemia-reperfusion injury was established by examining changes in renal function, intestinal barrier function, inflammatory index, oxidative stress, and macrophage phenotypes to evaluate the effect of probiotic VSL#3 on renal ischemia-reperfusion injury. The results showed that, after VSL#3 intervention, the levels of BUN, Scr, Cys C, PRO, and NGAL were all significantly decreased compared with the I/R group, while the value of Ccr showed a significant increase. In addition, the concentrations of MPO, IL-1β, TNF-α, IL-6, ED-1, and PCNA were all significantly lower than those in the I/R group, while the levels of endotoxin, DOA, and D-lactic acid were significantly decreased. Furthermore, the proteins associated with intestinal barrier functions, such as ZO-1, Occludin, and Claudin-1, were significantly upregulated compared with the I/R group. Overall, the VSL#3 intervention group was able to maintain the required number of beneficial intestinal flora and to inhibit the proliferation of harmful bacteria. At the same time, the VSL#3 intervention could also prevent the decrease in the levels of CAT, GSH-PX, H₂O₂, and T-SOD, while downregulating the expression of Keap1 and Nrf2. After the intervention with the VSL#3, the expression levels of CD68 and CD86 proteins were significantly decreased, while the expression levels of CD163 and CD206 proteins were significantly higher. Further experiments confirmed that the expression of iNOS protein was significantly decreased after the VSL#3 intervention, and the expression of Arg-1 and Ym1 proteins was significantly increased. The VSL#3 was able to induce high expressions of p-GSK-3β and p-PTEN proteins, while the use of IL-10 antibody impaired the effect of the VSL#3. In summary, this research confirms that probiotics can alleviate renal dysfunction caused by ischemia and reperfusion by protecting the intestinal barrier function and maintaining the functions of intestinal flora. The pathway screening test of this study suggests that IL-10/GSK3β/PTEN may play an important role in the process of the prototypic VSL#3 inducing M2 transformation of macrophages.

Diazoxide reduces local and remote organ damage in a rat model of intestinal ischemia reperfusion

BACKGROUND

Intestinal ischemia reperfusion is a common clinical condition that causes functional impairment. Once tight junctions are damaged, barrier function is compromised, and the intestines become a source for entry of bacterial and inflammatory mediators into the circulation, leading to systemic inflammatory response syndrome, multiple organ failure, and death. It is possible that diazoxide could protect the intestines against ischemia reperfusion. The aim of this study is to determine whether diazoxide can provide protection in a rat model of intestinal ischemia reperfusion.

METHODS

A total of 32 adult male specific pathogen-free Wistar rats were randomized into three groups: a control group, n = 6; a saline group, n = 13; and a diazoxide group, n = 13. The saline and diazoxide groups underwent clamping of the superior mesenteric artery for 1 h, with samples in all the groups being collected 12 h later.

RESULTS

Intestinal histology showed greater damage in the intestinal ischemia reperfusion groups. mRNA expression of zonula occludens-1 and occludin (tight junction proteins) and interleukin-6 and cyclooxygenase-2 was the highest in the Saline group. The Diazoxide group showed a reduction in aspartate aminotransferase serum levels compared with the other groups.

CONCLUSIONS

Increased expression of zonula occludens-1, occludin, and cyclooxygenase-2 suggested a greater regenerative effort because of more severe lesions in the saline group. In addition, increased expression of interleukin-6 in the saline group was suggestive of inflammation, indicating that diazoxide had protective effects in the diazoxide group. Reduced aspartate aminotransferase in the diazoxide group suggested liver protection. Diazoxide protects the intestines and liver from intestinal ischemia reperfusion lesions in rats.

Mesenteric Ischemia

Acute mesenteric ischemia (AMI) is a rare disease that most commonly affects the elderly. The vague symptoms often lead to delayed diagnosis and consequent high mortality. Physical exam and laboratory findings lack the sensitivity and specificity to exclude AMI, but computed tomography angiography can rapidly and accurately confirm the diagnosis. Survival improves with prompt restoration of perfusion and resection of nonviable bowel. Advances in imaging, operative techniques, and critical care have led to a steady decline in overall mortality; however, long-term survival is limited because of the comorbidities in this patient group.

Periarrest intestinal bacterial translocation and resuscitation outcome

During the periarrest period, intestinal ischemia may result in barrier dysfunction and bacterial translocation, which has clear mechanistic links to inflammation and cascade stimulation, especially in patients who are treated with therapeutic hypothermia. Despite optimal management, periarrest bacterial translocation may worsen the outcome of cardiac arrest victims.

[Acute mesenteric ischemia: do biomarkers contribute to diagnosis?]

Acute mesenteric ischemia is an emergency condition that requires immediate therapy. Despite advances in the fields of surgery and intensive therapy, the mortality of this condition remains high. This is due to the broad variability of clinical presentations and non-specific laboratory findings, which delay the diagnosis allowing the ischemia to progress and further worsening the patients' chances of survival. Thus, there is a significant need for reliable and enhanced serological markers of intestinal ischemia. The authors review the traditionally used and novel experimental serological markers for early diagnosis of mesenteric ischemia.