Nitric oxide donors improve gut function after prolonged hypothermic ischemia

Area of Science:

• Gastroenterology
• Physiology
• Transplantation

Background:

• Ischemia-reperfusion injury significantly compromises intestinal mucosal and microvascular function.
• Nitric oxide (NO) plays a critical role in regulating intestinal physiology and vascular tone.

Purpose of the Study:

• To investigate the effects of NO donors (spermine NO and SIN1) on feline small intestine responses to hypothermic ischemia and normothermic reperfusion.
• To determine if NO donors can mitigate intestinal injury during prolonged ischemia and subsequent reperfusion.

Main Methods:

• Feline small intestine preparations subjected to 6 hours of hypothermic ischemia followed by 2 hours of normothermic reperfusion.
• Administration of spermine NO or SIN1 to the luminal perfusate during reperfusion.
• Assessment of mucosal permeability using 51Cr-EDTA clearance.
• Measurement of lymph flow and lymphatic protein clearance to evaluate microvascular filtration and protein leakage.

Main Results:

• Both NO donors significantly attenuated the increase in mucosal permeability and improved net water absorption compared to controls.
• Spermine NO treatment led to a greater increase in intestinal lymph flow, lymphatic protein clearance, and capillary hydrostatic pressure.
• The protective effects on mucosal epithelium were observed without a direct correlation to microvascular alterations.

Conclusions:

• NO donors demonstrate a protective effect on the intestinal mucosal barrier following prolonged hypothermic ischemia and reperfusion.
• The beneficial impact of NO donors on mucosal integrity appears to be independent of their direct action on the intestinal microvasculature.
• NO donors hold potential therapeutic value for improving outcomes in intestinal allografts facing ischemic injury.