Objective: Chronic hyperglycemia characteristic of type diabetes 2 is responsible for the accelerated atherosclerosis with increased cardiovascular risk. In this study, we will propose to analyze the effect of a long-...Objective: Chronic hyperglycemia characteristic of type diabetes 2 is responsible for the accelerated atherosclerosis with increased cardiovascular risk. In this study, we will propose to analyze the effect of a long-term of glucotoxicity in vivo in Psammomys obesus by addition of sucrose to 30% for 11 months and in vitro study of adventitial fibroblasts in the presence of D-glucose 0.6% for 7 days. Materials and methods: Evaluation of plasma biochemical parameters was carried out at the initial time and at the end of experiment. At autopsy, a morphological study of the aorta was performed after fixation in aqueous Bouin and staining with Masson’s trichrome. The experimental glucotoxicity is induced by incubation of fibroblasts in DMEM enriched with D-glucose at 0.6% for 7 days. The impact of glucotoxicity is assessed in the intracellular compartments through dosage of total nitrite and malondialdehyde, a product of lipid peroxidation, and thanks to a morphological assay after fixation of cells with aqueous bouin and blood staining with May Grünwald Giemsa. The evaluation of cell proliferation is accomplished by cell counting. Collagens I and III of the extracellular compartment are characterized by SDS-PAGE. Results: Animals subjected to sucrose showed hyperglycemia associated with hyperinsulinemia, dyslipidemia, hyperproteinemia, increased CPK and VLDL-LDL and decreased HDL. Histology of aortas revealed endothelial cells hypertrophy, severe disorganization of intima and media. In the presence of glucose, the proliferation of fibroblasts increases very significantly (P = 2.34 × 10-5), the rate of malonaldehyde, nitrite and total density of chains α2 (I) and α1 (I + III) extra-cellular collagens I and III increased significantly. After staining, the cells showed hypertrophy, vacuolation of cytoplasm and chromatin condensation with nuclear fragmentation, indicative of apoptosis. Conclusion: The glucotoxicity induced in vivo and in vitro is responsible for major structural and metabolic alterations leading to the acceleration of the atherosclerotic process.展开更多
BACKGROUND The pancreatic islet microcirculation adapts its metabolism to cope with limited oxygen availability and nutrient delivery.In diabetes,the balance between oxygen delivery and consumption is impaired.Insulin...BACKGROUND The pancreatic islet microcirculation adapts its metabolism to cope with limited oxygen availability and nutrient delivery.In diabetes,the balance between oxygen delivery and consumption is impaired.Insulin has been proven to exert complex actions promoting the maintenance of homeostasis of the pancreas under glucotoxicity.AIM To test the hypothesis that insulin administration can improve the integrated pancreatic microcirculatory oxygen profile and bioenergetics.METHODS The pancreatic microcirculatory partial oxygen pressure(PO_(2)),relative hemoglobin(rHb)and hemoglobin oxygen saturation(SO_(2))were evaluated in nondiabetic,type 1 diabetes mellitus(T1DM),and insulin-treated mice.A threedimensional framework was generated to visualize the microcirculatory oxygen profile.Ultrastructural changes in the microvasculature were examined using transmission electron microscopy.An Extracellular Flux Analyzer was used to detect the real-time changes in bioenergetics by measuring the oxygen consumption rate and extracellular acidification rate in islet microvascular endothelial cells(IMECs).RESULTS Significantly lower PO_(2),rHb,and SO_(2) values were observed in T1DM mice than in nondiabetic controls.Insulin administration ameliorated the streptozotocin-induced decreases in these microcirculatory oxygen parameters and improved the mitochondrial ultrastructural abnormalities in IMECs.Bioenergetic profiling revealed that the IMECs did not have spare respiratory capacity.Insulin-treated IMECs exhibited significantly greater basal respiration than glucotoxicity-exposed IMECs(P<0.05).An energy map revealed increased energetic metabolism in insulin-treated IMECs,with significantly increased ATP production,non-mitochondrial respiration,and oxidative metabolism(all P<0.05).Significant negative correlations were revealed between microcirculatory SO_(2) and bioenergetic parameters.CONCLUSION Glucotoxicity deteriorates the integrated pancreatic microcirculatory oxygen profile and bioenergetics,but this deterioration can be reversed by insulin administration.展开更多
文摘Objective: Chronic hyperglycemia characteristic of type diabetes 2 is responsible for the accelerated atherosclerosis with increased cardiovascular risk. In this study, we will propose to analyze the effect of a long-term of glucotoxicity in vivo in Psammomys obesus by addition of sucrose to 30% for 11 months and in vitro study of adventitial fibroblasts in the presence of D-glucose 0.6% for 7 days. Materials and methods: Evaluation of plasma biochemical parameters was carried out at the initial time and at the end of experiment. At autopsy, a morphological study of the aorta was performed after fixation in aqueous Bouin and staining with Masson’s trichrome. The experimental glucotoxicity is induced by incubation of fibroblasts in DMEM enriched with D-glucose at 0.6% for 7 days. The impact of glucotoxicity is assessed in the intracellular compartments through dosage of total nitrite and malondialdehyde, a product of lipid peroxidation, and thanks to a morphological assay after fixation of cells with aqueous bouin and blood staining with May Grünwald Giemsa. The evaluation of cell proliferation is accomplished by cell counting. Collagens I and III of the extracellular compartment are characterized by SDS-PAGE. Results: Animals subjected to sucrose showed hyperglycemia associated with hyperinsulinemia, dyslipidemia, hyperproteinemia, increased CPK and VLDL-LDL and decreased HDL. Histology of aortas revealed endothelial cells hypertrophy, severe disorganization of intima and media. In the presence of glucose, the proliferation of fibroblasts increases very significantly (P = 2.34 × 10-5), the rate of malonaldehyde, nitrite and total density of chains α2 (I) and α1 (I + III) extra-cellular collagens I and III increased significantly. After staining, the cells showed hypertrophy, vacuolation of cytoplasm and chromatin condensation with nuclear fragmentation, indicative of apoptosis. Conclusion: The glucotoxicity induced in vivo and in vitro is responsible for major structural and metabolic alterations leading to the acceleration of the atherosclerotic process.
基金Supported by the Beijing Municipal Natural Science Foundation,No.7212068the National Natural Science Foundation of China,No.81900747.
文摘BACKGROUND The pancreatic islet microcirculation adapts its metabolism to cope with limited oxygen availability and nutrient delivery.In diabetes,the balance between oxygen delivery and consumption is impaired.Insulin has been proven to exert complex actions promoting the maintenance of homeostasis of the pancreas under glucotoxicity.AIM To test the hypothesis that insulin administration can improve the integrated pancreatic microcirculatory oxygen profile and bioenergetics.METHODS The pancreatic microcirculatory partial oxygen pressure(PO_(2)),relative hemoglobin(rHb)and hemoglobin oxygen saturation(SO_(2))were evaluated in nondiabetic,type 1 diabetes mellitus(T1DM),and insulin-treated mice.A threedimensional framework was generated to visualize the microcirculatory oxygen profile.Ultrastructural changes in the microvasculature were examined using transmission electron microscopy.An Extracellular Flux Analyzer was used to detect the real-time changes in bioenergetics by measuring the oxygen consumption rate and extracellular acidification rate in islet microvascular endothelial cells(IMECs).RESULTS Significantly lower PO_(2),rHb,and SO_(2) values were observed in T1DM mice than in nondiabetic controls.Insulin administration ameliorated the streptozotocin-induced decreases in these microcirculatory oxygen parameters and improved the mitochondrial ultrastructural abnormalities in IMECs.Bioenergetic profiling revealed that the IMECs did not have spare respiratory capacity.Insulin-treated IMECs exhibited significantly greater basal respiration than glucotoxicity-exposed IMECs(P<0.05).An energy map revealed increased energetic metabolism in insulin-treated IMECs,with significantly increased ATP production,non-mitochondrial respiration,and oxidative metabolism(all P<0.05).Significant negative correlations were revealed between microcirculatory SO_(2) and bioenergetic parameters.CONCLUSION Glucotoxicity deteriorates the integrated pancreatic microcirculatory oxygen profile and bioenergetics,but this deterioration can be reversed by insulin administration.
