Stimulation of the peroxisome proliferator-activated receptor gamma (PPAR gamma) and the expression of selected blood monocyte cytokine genes in diabetic macroangiopathy.

Monocytes and macrophages play a key role in the progression of atheromatous changes. The peroxisome proliferator-activated receptor gamma (PPAR gamma) can limit macroangiopathy through the control of cytokine transcription. The objectives of this study were to examine the influence of PPAR gamma and its agonist (rosiglitazone) on the TNFalpha, IL-6, IL-8 and IL-10 gene expression in monocytes of patients with diabetic macroangiopathy and to analyse obtained results in context of selected atherogenic factors ant direct indicators of endothelial lesion. TNFalpha, IL-6, IL-8, IL-10 and PPAR gamma gene expression was assessed in peripheral blood monocytes in 45 patients with type 2 diabetes before and following 22 weeks of rosiglitazone therapy (real-time PCR [Applied Biosystems]). As indicators of endothelial lesion, concentration of thrombomodulin (immunoassay [Diagnostica Stago]) and amount of circulating blood endothelial cells (immunofluorescence method with MoAb CLB-HEC19) were determined. Following rosiglitazone therapy, a statistically significant downward tendency of TNFalpha (p=0.026) and IL-8 (p=0.008) gene expression was noted. Before and following rosiglitazone treatment, PPAR gamma, IL-6 and IL-10 gene expression was undetectable in studied monocytes in vivo. In conclusion, TNFalpha and IL-8 play an important role in monocyte atherogenic activity. Rosiglitazone reduces monocyte proinflammatory readiness by influencing the expression of selected atherogenic cytokines (PPAR gamma-independent pathway).