Advanced glycosylated end products-mediated activation of polymorphonuclear neutrophils in diabetes mellitus and associated oxidative stress.

Two important consequences of hyperglycemia in diabetes are development of oxidative stress and formation of advanced glycation end products (AGE) which are known to be associated with diabetic complications. Relationship between AGE formation and development of oxidative stress (OS) is yet to be established. In the present study, the involvement of AGE in PMN-mediated ROS generation and the associated OS were investigated in type 2 diabetic mellitus (DM) patients. We assessed OS parameters (serum MDA, FRAP and GSH), PMN oxidative functions (respiratory burst and superoxide production) and total serum AGE in 90 subjects divided equally in three groups--control group, Group I consisting of type 2 diabetic patients without microvascular complications and Group II consisting of type 2 diabetic patients with microvascular complications. PMNs isolated from both groups (I and II) exhibited higher level of respiratory burst (RB) and produced increased amount of superoxide anion as compared to the controls. The increase was more pronounced in diabetes with complications, as compared to those without. Serum malondialdehyde (MDA) level was elevated, whereas glutathione (GSH) and ferric reducing ability of plasma (FRAP) levels were significantly reduced in diabetes as compared to the controls, suggesting the presence of oxidative stress in DM. A positive correlation between PMN oxidative function and OS parameters suggested the involvement of PMN in the development of OS in DM. Serum AGE level was also elevated in diabetic groups as compared to the controls. Further, the positive correlation between serum AGE level and PMN oxidative function suggested the involvement of AGE in increased RB and generation of reactive oxygen species (ROS) by resting diabetic PMN. The results of the study indicate that AGE-PMN interaction possibly upregulates NADPH oxidase, leading to enhanced ROS generation and thus contributes to the pathogenesis in diabetes.

Phagocytic response of leucocytes in secretors and non-secretors of ABH (O) blood group substances.

Secretor status of healthy young volunteers in the age group of 18-22 years and having similar socio-economic background was determined by standard agglutination inhibition test of the saliva. Phagocytic response of leucocyte was worked out by in vitro suspension technique and average number of cocci engulfed by leucocytes calculated in secretors/non-secretors of each blood group. Leucocytes of non-secretors of O and AB seem to have more and highly significant ingestion power as compared to secretors. Non secretors in group A & B also show more phagocytic activity. Relatively different concentration of the components of the blood group substances in secretors/non-secretors seems to affect phagocytic activity of the leucocytes.