Allopurinol attenuated the chemically-induced hypoxia (hypoxia-reoxygenation) injuries via down-regulation of the transcription factor HIF-1α in neuroblastoma cells

High-resolution magic angle spinning nuclear magnetic resonance of donor pancreatic tissue may predict islet viability prior to isolation

For patients with type 1 diabetes mellitus complicated by severe hypoglycemia, clinical islet transplantation is an efficacious alternative to whole pancreas transplantation. While islet transplantation has improved over the last few years, there remain questions regarding its cost-effectiveness and donor allosensitization, which is exacerbated when islets from more than one donor are required. Understanding the features of a pancreas that would provide viable islets prior to isolation may lead to development of an accurate assay that could identify suitable pancreases and provide significant cost savings to a clinical islet transplantation program. In this pilot study, solid-state high-resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) spectroscopy was used to assess samples of convenience of human pancreatic tissue taken prior to islet isolation both before and after incubation using the two-layer perfluorocarbon (PFC)/University of Wisconsin (UW) solution cold-storage method. We observed that, prior to incubation, human pancreatic tissue exhibited evidence of hypoxia with decreased peak integrals associated with glucose and increased peak integrals corresponding to lactate and free fatty acids. After incubation, we observed a reversal of the hypoxia-induced damage, as integrals corresponding to glucose increased, and those corresponding to lactate and free fatty acid resonances decreased. Interestingly, a significant correlation between the ratio of the glucose integral (at 3.0-4.5 ppm) to the sum of the fatty acid (at 0.9 ppm) and lactate + fatty acid (at 1.3 ppm) integrals and glucose responsiveness, a measure of islet viability, of the isolated islets, was observed after incubation in PFC/UW solution for pancreases that responded to PFC/UW solution incubation (p = 0.02). Notably, pancreases with little or no change in the integral ratio after PFC/UW solution incubation had poor recovery. These results suggest that tissue recovery is a key feature for determining islet cell viability, and further that HRMAS NMR may be a practical method to quickly assess human donor pancreatic tissue prior to islet isolation for clinical transplantation.

Curcumin pretreatment protects against hypoxia/reoxgenation injury via improvement of mitochondrial function, destabilization of HIF-1α and activation of Epac1-Akt pathway in rat bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (BMSCs) possess promising therapeutic effects and have been considered as a highly desirable agent for tissue injury treatment. However, little survived cells after transplanting due to severe relocated conditions (characterized by prolonged hypoxia and oxidative stress) lead to hampered benefits of BMSCs-based cell therapy. Curcumin, a natural dietary product, has attracted increasing attention owing to its profound pharmacologic properties. Here, we report the protective effects of curcumin pretreatment in BMSCs against hypoxia and reoxygenation (H/R) triggered injury, which mimick ischemia/reperfusion in vivo. We found that curcumin pretreatment remarkably inhibited H/R-induced cell viability loss, cell nuclei condensation, LDH leakage, as well as caspase-3 activity increase in BMSCs. Furthermore, curcumin pretreatment prevented H/R-induced mitochondrial dysfunction through expediting adenosine triphosphate production and suppressing reactive oxygen species accumulation and mitochondrial membrane potential decline. In addition, curcumin pretreatment notably induced HIF-1α destabilization, Epac1 and Akt activation, and Erk1/2 and p38 deactivation. However, Epac1 inhibitor ESI-09 obviously restrained the increase of p-Akt induced by curcumin, but not p-Erk1/2 or p-p38, and abrogated the protective effect of curcumin on BMSCs' survival and arrested cell cycle in G0/G1 phase. Taken together, these results demonstrated that curcumin pretreatment conferred BMSCs the ability to survive from H/R injury, which might attribute to its protection on mitochondrial function, destabilization of HIF-1α and activation of Epac1-Akt signaling pathway. Thus, this study provides more pharmacologic aspects of curcumin, and suggests that pre-conditioning of BMSCs with curcumin could serve as an attractive approach for facilitating cell therapy in tissue repair treatment.