Abstract
Background: Peritoneal dialysis solution (PDS) dilates peritoneal microvessels predominantly by the activation of the endothelial nitric oxide (NO) pathway. We made an incidental observation of decreased PDS-induced, NO-dependent peritoneal microvascular vasoreactivity in elderly rats naïve to PDS exposure. We hypothesized that this subordinate NO-mediated peritoneal microvascular vasoreactivity is caused by increased oxidative stress in the aged endothelium, which compromises NO bioavailability in the elderly, and that peritoneal microvascular vasoreactivity can be improved by the supplementation of antioxidant glycine to PDS. Methods: We studied PDS-mediated vasoreactivity of four intestinal visceral arterioles of different orders by in vivo intravital microscopy in weaned, adult, and elderly rats to (i) confirm subordinate vasoreactivity to PDS in elderly rats; (ii) restore vasoreactivity by glycine supplementation; and (iii) establish age as an independent risk factor for endothelial cell dysfunction. Results: In a crossover series, peritoneal microvascular vasoreactivity to PDS exposure was remarkably decreased in elderly rats. This subordinate vasoreactivity was completely restored by the supplementation of glycine to PDS. In a separate series, we assessed in situ endothelial cell function in weaned and adult rats using the cumulative acetylcholine concentration–response curves. Unlike the adults, the weaned rats demonstrated remarkable sensitivity and reactivity to cumulative acetylcholine concentrations, suggesting the dependency of endothelial cell function on age. Conclusion: Aging is an independent risk factor for peritoneal microvascular endothelial cell dysfunction. Endothelial function in the elderly can be recovered by reinforcing the bioavailability of endothelial-derived NO through glycine. Dietary glycine supplementation is a potential therapeutic strategy to decrease the burden of oxidative stress on the aged endothelium.
Highlights
Peritoneal dialysis (PD) is a form of renal replacement therapy for patients with end-stage renal failure
Dietary glycine supplementation is a potential therapeutic strategy to decrease the burden of oxidative stress on the aged endothelium
Images of the arterioles were recorded in a streamline video that was automatically saved to the computer hard drive for offline measurements of diameter by digital calipers. The objective of this crossover series was twofold: (1) to confirm the subordinate vasoreactivity of the aged microvasculature upon exposure to Peritoneal dialysis solution (PDS) and (2) to demonstrate that exposure of the aged microvasculature to PDS supplemented with glycine restores the vasoreactivity of the microvasculature
Summary
Peritoneal dialysis (PD) is a form of renal replacement therapy for patients with end-stage renal failure. We made an incidental observation that the peritoneal microvascular response to PDS is impaired in elderly rats naïve to PDS exposure. We made an incidental observation of decreased PDS-induced, NO-dependent peritoneal microvascular vasoreactivity in elderly rats naïve to PDS exposure. We hypothesized that this subordinate NO-mediated peritoneal microvascular vasoreactivity is caused by increased oxidative stress in the aged endothelium, which compromises NO bioavailability in the elderly, and that peritoneal microvascular vasoreactivity can be improved by the supplementation of antioxidant glycine to PDS. Results: In a crossover series, peritoneal microvascular vasoreactivity to PDS exposure was remarkably decreased in elderly rats This subordinate vasoreactivity was completely restored by the supplementation of glycine to PDS. Endothelial function in the elderly can be recovered by QATAR MEDICAL JOURNAL 1
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
