BackgroundThe success of pancreatic islet transplantation still faces many challenges, mainly related to cell damage during islet isolation and early post-transplant. The increased generation of reactive oxygen species (ROS) during islet isolation and the consumption of antioxidant defenses appear to be an important pathway related to islet damage.Methodology/Principal FindingsIn the present study we evaluated whether supplementation of glutathione-ethyl-ester (GEE) during islet isolation could improve islet viability and transplant outcomes in a murine marginal islet mass model. We also cultured human islets for 24 hours in standard CMRL media with or without GEE supplementation. Supplementation of GEE decreased the content of ROS in isolated islets, leading to a decrease in apoptosis and maintenance of islet viability. A higher percentage of mice transplanted with a marginal mass of GEE treated islets became euglycemic after transplant. The supplementation of 20 mM GEE in cultured human islets significantly reduced the apoptosis rate in comparison to untreated islets.Conclusions/SignificanceGEE supplementation was able to decrease the apoptosis rate and intracellular content of ROS in isolated islets and might be considered a potential intervention to improve islet viability during the isolation process and maintenance in culture before islet transplantation.

Background: No formulation of exogenous insulin available to date has yet been able to mimic the physiological nictemeral rhythms of this hormone, and despite all engineering advancements, the theoretical proposal of developing a mechanical replacement for pancreatic β cell still has not been reached. Thus, the replacement of β cells through pancreas and pancreatic islet transplantation are the only concrete alternatives for re-establishing the endogenous insulin secretion in type 1 diabetic patients. Since only 1 to 1.5% of the pancreatic mass corresponds to endocrine tissue, pancreatic islets transplantation arises as a natural alternative. Data from the International Islet Transplant Registry (ITR) from 1983 to December 2000 document a total of 493 transplants performed around the world, with progressively worse rates of post-transplant insulin independence. In 2000, the "Edmonton Protocol" introduced several modifications to the transplantation procedure, such as the use of a steroid-free immunosuppression regimen and transplantation of a mean islet mass of 11,000 islet equivalents per kilogram, which significantly improved 1-year outcomes. Although the results of a 5-year follow-up in 65 patients demonstrated improvement in glycemic instability in a significant portion of them, only 7.5% of the patients have reached insulin independence, indicating the need of further advances in the preservation of the function of transplanted islet. In addition to the scarcity of organs available for transplantation, islets transplantation still faces major challenges, specially those related to cell loss during the process of islet isolation and the losses related to the graft site, apoptosis, allorejection, autoimmunity, and immunosuppression. The main strategies to optimize islet transplantation aim at improving all these aspects.

SUMÁRIODescrevemos uma paciente com diabetes tipo 1 com acne e insuficiência renal crônica, em diálise, que apresentou uma dosagem de testosterona total e livre elevada (612 ng/dL, normal < 90 ng/dL e 255 pMol/L, normal: 20-45 pMol/L, respectivamente). Na avaliação clínica, além da acne facial não havia qualquer outro sinal de hiperandrogenismo. Após ter esse resultado confirmado, ela foi submetida à avaliação morfológica de adrenal e ovários (tomografia computadorizada de adrenal e ultrassom pélvico), cujos resultados foram normais. Na ausência de quadro clínico de virilização, foram consideradas outras possibilidades que pudessem explicar a elevação da testosterona, entre as quais a presença de comorbidades (diabetes e insuficiência renal crônica) e falha do método de dosagem. Uma nova determinação da testosterona total, por meio da cromatografia líquida de alta performance como método preparativo e espectrometria de massa em tandem, resultou normal (21 ng/dL), compatível com uma concentração de testosterona total falsamente elevada pela presença de interferentes com o método de dosagem. Arq Bras Endocrinol Metab. 2012;56(5):319-23 SUMMARYThe purpose of this report is to present the case of a patient with type 1 diabetes with acne and chronic renal failure on dialysis admitted to the hospital with high total total and free testosterone (612 ng/dL, normal < 90 ng/dL; 255 pMol/L, normal: 20-45 pMol/L). On clinical evalua tion, she presented facial acne, and no other signs of hyperandrogenism. As this result was confirmed, she underwent adrenal and ovary morphological assessment (adrenal CT and pelvic ultrasound), which yielded normal results. Due to divergence between clinical and laboratory findings, we considered other possibilities that could explain the elevation of testosterone, including the presence of comorbidities (diabetes and chronic renal failure) and failure of the testosterone assay. Testosterone levels were determined again by high performance liquid chromatography, as a preparative method, and tandem mass spectrometry, yielding normal results (21 ng/dL), which were compatible with a falsely elevated total testosterone level caused by the presence of factors that intereferred with the assay. INTRODUÇÃO A s síndromes hiperandrogênicas englobam doenças que se manifestam pelo aumento da atividade biológica dos andrógenos. Na mulher, essas manifestações incluem hirsutismo, acne, alopecia tipo androgêni-ca, disfunção menstrual, infertilidade, abortamento precoce e sinais de virilização (atrofia do parênquima mamário, alteração da tonalidade da voz, redistribuição de massas musculares e clitoromegalia).Tanto a testosterona total (forma livre e forma ligada às proteínas transportadoras) quanto a testosterona livre são consideradas marcadores sensíveis para a demonstração da hiperandrogenemia (1). Entretanto, não existe correlação entre a concentração dos andrógenos

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