ABSTRACT
Currently there is no effective approach for monitoring early ß-cell loss during islet graft rejection following human islet transplantation (HIT). Due to ethical and technical constraints, it is difficult to directly study biomarkers of islet destruction in humans. Here, we established a humanized mouse model with induced human ß-cell death using adoptive lymphocyte transfer (ALT). Human islet grafts of ALT-treated mice had perigraft lymphocyte infiltration, fewer insulin+ ß cells, and increased ß-cell apoptosis. Islet-specific miR-375 was used to validate our model, and expression of miR-375 was significantly decreased in the grafts and increased in the circulation of ALT-treated mice before hyperglycemia. A NanoString expression assay was further used to profile 800 human miRNAs in the human islet grafts, and the results were validated using quantitative real-time polymerase chain reaction. We found that miR-4454 and miR-199a-5p were decreased in the human islet grafts following ALT and increased in the circulation prior to hyperglycemia. These data demonstrate that our in vivo model of induced human ß-cell destruction is a robust method for identifying and characterizing circulating biomarkers, and suggest that miR-4454 and miR-199a-5p can serve as novel biomarkers associated with early human ß-cell loss following HIT.
Subject(s)
Diabetes Mellitus, Experimental/genetics , Disease Models, Animal , Insulin-Secreting Cells/pathology , Islets of Langerhans Transplantation , MicroRNAs/genetics , Adoptive Transfer , Animals , Apoptosis , Diabetes Mellitus, Experimental/blood , Diabetes Mellitus, Experimental/therapy , Female , Graft Survival , Humans , Hyperglycemia/etiology , Insulin-Secreting Cells/metabolism , Lymphocytes/immunology , Lymphocytes/pathology , Male , Mice , Mice, Inbred NOD , Mice, SCIDABSTRACT
PURPOSE: Despite the proven benefits of antimicrobial stewardship, models for executing the same in the developing countries are sparse. The present study highlights the approaches undertaken by our group in initiating one such program in a public sector tertiary level health care setting of a developing country. METHODS: The study focussed on development of a system after evaluation of existing issues and case study of implementation of the program in a unit within the hospital. The system building exercise included (1) development of generic data capture form for prospective audit and feedback; (2) development of an electronic system for data capture; (3) identification of key intervention points for strategy decision for stewardship in a particular unit; (4) application of the stewardship method and (5) evaluation of outcomes. RESULTS: A digital system for prospective audit was constructed after a background study. In the study unit, there was a significant decline in double anaerobic coverage. There was a significant decline in the average number of antimicrobials used per patients and a decrease in Defined Daily Dose of designated antimicrobials was noted. Additionally, there was an increase in the use of optimized doses. CONCLUSION: A system for undertaking antimicrobial stewardship with a mechanism for prospective audit was put in place. The system may be adopted by other public sector hospitals of the developing country.
Subject(s)
Anti-Infective Agents/therapeutic use , Developing Countries , Drug Utilization Review/methods , Drug Utilization/statistics & numerical data , Hospitals, Public , Humans , India , Models, Theoretical , Prospective Studies , Tertiary Care CentersABSTRACT
The excess accumulation of lipids in islets is thought to contribute to the development of diabetes in obesity by impairing beta-cell function. However, lipids also serve a nutrient function in islets, and fatty acids acutely increase insulin secretion. A better understanding of lipid metabolism in islets will shed light on complex effects of lipids on beta-cells. Adipose differentiation-related protein (ADFP) is localized on the surface of lipid droplets in a wide range of cells and plays an important role in intracellular lipid metabolism. We found that ADFP was highly expressed in murine beta-cells. Moreover, islet ADFP was increased in mice on a high-fat diet (3.5-fold of control) and after fasting (2.5-fold of control), revealing dynamic changes in ADFP in response to metabolic cues. ADFP expression was also increased by addition of fatty acids in human islets. The downregulation of ADFP in MIN6 cells by antisense oligonucleotide (ASO) suppressed the accumulation of triglycerides upon fatty acid loading (56% of control) along with a reduction in the mRNA levels of lipogenic genes such as diacylglycerol O-acyltransferase-2 and fatty acid synthase. Fatty acid uptake, oxidation, and lipolysis were also reduced by downregulation of ADFP. Moreover, the reduction of ADFP impaired the ability of palmitate to increase insulin secretion. These findings demonstrate that ADFP is important in regulation of lipid metabolism and insulin secretion in beta-cells.
