Compositional alterations in erythrocyte membranes in Type II diabetes

Loss of erythrocyte membrane deformability is one of the most crucial factors in developing complications associated with Type II diabetes. The observed loss of erythrocyte membrane deformability could be related to structural changes in the membrane. In this context, here, we have made an attempt at gaining a better insight (quantitative as well as qualitative) into the protein and lipid contents in erythrocyte membranes and their interrelationships in Type II diabetes. Age matched control (n=12) and Type II diabetic subjects (n=22) were selected for this study. Morphological characteristics were studied by atomic force microscopy (AFM). AFM study confirmed remarkable alterations in morphology of the diabetic erythrocytes. In diabetic erythrocytes following changes were noted: (i) Significant increase in membrane as well as cytosolic proteins with a marginal increase in phospholipids content; (ii) The membrane total lipids:protein, phospholipids:protein, cholesterol:protein and phospholipids:cholesterol (mole:mole) ratios decreased significantly; (iii). A reproducible decrease in docosahexaenoic acid (DHA) and Omega-3 index with increase in Omega-6:Omega-3 ratio in membrane fatty acids; and (iv) The SDS-PAGE analysis indicated that all membrane proteins increased in almost equal proportion leading to increased membrane protein content. The observed compositional and stochiometric changes in lipids, proteins and their ratios may underlie morphological alterations and loss of deformability

Compositional alterations in erythrocyte membranes in Type II diabetes

671-679Loss of erythrocyte membrane deformability is one of the most crucial factors in developing complications associated with Type II diabetes. The observed loss of erythrocyte membrane deformability could be related to structural changes in the membrane. In this context, here, we have made an attempt at gaining a better insight (quantitative as well as qualitative) into the protein and lipid contents in erythrocyte membranes and their interrelationships in Type II diabetes. Age matched control (n=12) and Type II diabetic subjects (n=22) were selected for this study. Morphological characteristics were studied by atomic force microscopy (AFM). AFM study confirmed remarkable alterations in morphology of the diabetic erythrocytes. In diabetic erythrocytes following changes were noted: (i) Significant increase in membrane as well as cytosolic proteins with a marginal increase in phospholipids content; (ii) The membrane total lipids:protein, phospholipids:protein, cholesterol:protein and phospholipids:cholesterol (mole:mole) ratios decreased significantly; (iii). A reproducible decrease in docosahexaenoic acid (DHA) and Omega-3 index with increase in Omega-6:Omega-3 ratio in membrane fatty acids; and (iv) The SDS-PAGE analysis indicated that all membrane proteins increased in almost equal proportion leading to increased membrane protein content. The observed compositional and stochiometric changes in lipids, proteins and their ratios may underlie morphological alterations and loss of deformability

Evaluation of the bioavailability of major withanolides of Withania somnifera using an in vitro absorption model system

Withania somnifera (L.) Dunal, shows several pharmacological properties which are attributed mainly to the withanolides present in the root. The efficacy of medicinally active withanolides constituents depends on the absorption and transportation through the intestinal epithelium. We examined these characteristics by employing the Sino-Veda Madin-Darby canine kidney cells culture system, which under in vitro condition shows the absorption characteristics similar to the human intestinal epithelium. Thus, the aim of the present investigation was to assess the bioavailability of individual withanolides. Withanolides were diluted in Hank′s buffered saline at a concentration of 2 μg/ml were tested for permeability studies carried out for 1 h duration. Permeability was measured in terms of efflux pump (Peff ) in cm/s. Peff values of withanolide A (WN A), withanone (WNN), 1,2-deoxywithastramonolide (1,2 DWM), withanolide B (WN B), withanoside IV-V (WS IV-V), and withaferin A were 4.05 × 10−5 , 2.06 × 10−5 , 1.97 × 10−5 , 1.80 × 10−5 , 3.19 × 10−6 , 3.03 × 10−6 and 3.30 × 10−7 respectively. In conclusion, the nonpolar and low molecular weight compounds (WN A, WNN, 1,2 DWM, and WN B) were highly permeable. As against this, the glycosylated and polar WS IV and WS V showed low permeability. Surprisingly and paradoxically, the highly biologically active withaferin A was completely impermeable, suggesting that further studies possibly using human epithelial colorectal adenocarcinoma (Caco-2) cells may be needed to delineate the absorption characteristics of withanolides, especially withaferin A