Reduced number of cirkulating monocytes after institution of insulin therapy: Relevance for development of atherosclerosis in diabetics?

Abstract Twelve patients with Type I1 diabetes mellitus, insufficiently controlled with oral hypoglycaemic agents, were studied before, after 2 months, and after 4 months on insulin therapy. For comparison the same variables were also studied in 10 healthy subjects. From the start, in the diabetic group, the authors found alterations in the hemorheologic parameters indicated by increased values for whole blood viscosity, plasma viscosity, red cell transit time (RCTT), and decreased values for white cell initial relative filtration rate (IrFR). In hematologic parameters they found increased values for mean corpuscular volume (MCV), leukocyte count, counts of neutrophils and rnonocytes, and a decreased count of lymphocytes. They also found increased values in the lipid parameters P-triglycerides and Apo B/Apo A-I ratio, risk factors of coronary atherosclerosis. After 4 months of insu!in treatment whole blood and plasma viscosity were still increased. but there was a partial improvement of lipoprotein abnormalities. Red and white cell filterability, however, tended to normalize. These results indicate that changes in blood cell filterability do not necessarily influence in vitro measurements of blood viscosity. The change in RCTT during the insulin treatment was associated with a decreased MCV and the change in white cell IrFR with a decrease in the number of monocytes. This change of white cell filterability during insulin therapy, probably due to a reduced number of monocytes, may be of interest in the study of atherosclerosis and circulatory disease in diabetics.