To evaluate the effect of gliclazide administration to NIDDM patients on 1) monocyte adhesion to cultured endothelial cells, 2) plasma cytokine and lipid peroxide levels, and 3) monocyte cytokine production.
Poorly controlled glyburide-treated diabetic patients (n = 8) and healthy control subjects (n = 8) were recruited. At the beginning of the study, glyburide was replaced by an equivalent hypoglycemic dose of gliclazide. Serum and monocytes were isolated from blood obtained from control and diabetic subjects before and after 3 months of treatment with gliclazide.
Plasma lipid peroxide levels and monocyte adhesion to endothelial cells are enhanced in NIDDM patients, and gliclazide administration totally reverses these abnormalities. Before gliclazide treatment, serum levels of cytokines did not differ in the control and the diabetic groups, with the exception of an enhancement of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL)-6 in NIDDM subjects. Basal and lipopolysaccharide (LPS)-stimulated monocyte production of interleukin-1β, IL-6, and IL-8 did not differ between the two groups. Furthermore, basal monocyte production of TNF-α was similar in the control and the diabetic groups, whereas a marked increase in the LPS-stimulated monocyte production of TNF-α was observed in the NIDDM group. Gliclazide treatment lowered LPS-stimulated TNF-α production by diabetic monocytes to levels similar to those observed in control subjects.
Gliclazide administration to NIDDM patients inhibits the increased adhesiveness of diabetic monocytes to endothelial cells and reduces the production of TNF-α by these cells. These results suggest that treatment of NIDDM subjects with gliclazide may be beneficial in the prevention of atherosclerosis associated with NIDDM.