Postconditioning of the small intestine: which is the most effective algorithm in a rat model?

BACKGROUND: Mesenteric ischemia is a serious clinical condition requiring immediate surgical intervention. The unavoidable ischemic-reperfusion (IR) injury may be ameliorated using the appropriate postconditioning protocol. The aim of the present study was to investigate the optimal postconditioning algorithm in a rat model of intestinal ischemic-reperfusion injury. MATERIALS AND METHODS: Male Wistar rats were randomized into five groups (n = 10), one sham-operated, one IR, and three postconditioned groups, each with different protocols. The animals were subjected to 60 min of mesenteric ischemia, followed by 60 min of reperfusion. Postconditioning was applied at the onset of reperfusion using three different algorithms. Arterial pressure and mucosal microcirculation were monitored throughout the experiment. Mesenteric pH was determined at the early phase of reperfusion. Blood and tissue samples were taken at the end of reperfusion for histologic evaluation, serum lactate dehydrogenase, serum creatine kinase, serum tumor necrosis factor-α, serum interleukin-6, detailed mucosal antioxidant, and scavenger capacity assays. RESULTS: The shorter and intermediate length cycles of postconditioning enhanced mucosal microcirculation and redox state and significantly delayed the normalization of mesenteric pH. Furthermore, milder histopathologic lesions and lower concentrations of serum necroenzymes and proinflammatory cytokines were detected compared with the IR group. The protective effect of postconditioning using longer cycles could only be seen in a tendentious manner. CONCLUSIONS: In a rat model of intestinal ischemia-reperfusion, the shorter and intermediate length cycles of postconditioning proved to be more effective than the use of longer cycles.

Effects of Short-Peptide-Based Enteral Nutrition on the Intestinal Microcirculation and Mucosal Barrier in Mice with Severe Acute Pancreatitis.

SCOPE: Short-peptide-based enteral nutrition (SPEN) is absorbed more efficiently in patients with severe acute pancreatitis (SAP). More importantly, SPEN decreases SAP-induced enterogenous infection risk. This study aims to investigate whether SPEN alleviates intestinal bacterial translocation in mice with SAP, and the underlying mechanisms. METHODS AND RESULTS: The SAP model is established after pre-treatment with SPEN or intact-protein-based enteral nutrition. Although there is no improvement in pancreas injury, as evaluated through Hematoxylin-Eosin staining or serum amylase, SPEN obviously attenuates intestinal bacterial translocation after SAP. To unveil the mechanisms, it is found that the intestinal mechanical barrier destroyed by SAP is significantly relieved by SPEN, which presents with recovered ZO-1 expression, mucus layer, and goblet cell function. Additionally, SPEN alleviates local CCR6/CCL20 induced CD11c+ dendritic cell infiltration, systemic immunosuppression, and inhibits the secretion of luminal secretory immunoglobulin A. Possibly responsible for SAP-induced mucosal dysfunctions, destroyed intestinal mucosal microcirculation and local hypoxia are largely improved in SAP+SPEN group. CONCLUSION: SPEN can improve downregulated intestinal mucosal microcirculation secondary to SAP, which may be responsible for mucosal inflammation relief, maintenance of the mechanical barrier and mucosal immunity, the correction of systemic immunosuppression, and play a protective role in defending commensal bacterial translocation after SAP.

Effect of Hot Steam Inhalation on Microcirculation of Nasal Mucosa

BACKGROUND AND OBJECTIVES: Nasal inhalation of hot humidified air may alleviate nasal symptoms associated with rhinologic disease. Thus, hot steam inhalation is often recommended as a home remedy for various nasal disorders such as the common cold and allergic rhinitis. But the mechanism of its effect is not fully known and correct guidelines for implementing hot steam inhalation have not been settled. We studied microcirculation of nasal mucosa using the nasal Laser Doppler Flowmetry (LDF) in ten healthy subjects in order to evaluate normal physiologic reactions to hot steam. MATERIALS AND METHODS: 10 healthy volunteers inhaled hot steam (about 42degrees C) 10 times, 20 times, 30 times, 50 times and 100 times respectively. Nasal LDF was then performed using a Peiflux 4001 (Perimed, Jartalla, Sweden) and the microcirculatory parameters perfusion, velocity, and concentration were each recorded at base line immediately, 15 minutes, 30 minutes, 60 minutes, 90 minutes and 120 minutes after hot steam inhalation. RESULT: Microcirculatory perfusion was highest at 15 minutes after hot steam inhalation regardless of how many times inhalation occurred. It was found that at 15 minutes, there was a significant increase of microcirculatory perfusion in subjects inhaling 50 times and 100 times (p<0.05). But, at 120 minutes, significant increase of microcirculatory perfusion was only seen in subjects inhaling 100 times (p<0.05). CONCLUSION: After inhalation of hot steam, an increased microcirculatory perfusion of nasal mucosa was registered. Up to inhaling of 100 times, it leads to effective increasement of microcirculation of nasal mucosa.