Monocyte Function and Inflammation in Type 1 Diabetes and Its Modulation

Overview

Type I diabetes (T1DM) is associated with an increased risk of vascular complications. While the precise mechanism(s) by which diabetes accelerates atherosclerosis has not been elucidated, several lines of evidence point to the role of increased inflammation in the pathogenesis of these vasculopathies. The monocyte-macrophage is a pivotal cell in atherogenesis and is readily accessible for study. However, there is scanty data on monocyte function and inflammation in T1DM. Simvastatin, a HMG-CoA reductase inhibitor, has recently been shown to reduce cardiovascular events in diabetic patients (T1DM and T2DM in the Heart Protection Study). Recent studies demonstrate that simvastatin decreased C-reactive protein and decreased pro-atherogenic activity of monocytes in non-diabetic subjects. However, there is a paucity of data on the effect of simvastatin on inflammation and monocyte function in Type 1 diabetes. Thus, the purpose of this study is Aim 1) to assess biomarkers of inflammation in T1DM compared to matched controls (n=50/group). Aim 2) Also, we will assess the effect of simvastatin (20mg/day) therapy on inflammation and monocyte function in T1DM in a randomized, placebo-controlled, double blind trial.

Type I diabetes (T1DM) is associated with an increased risk of vascular complications. While the precise mechanism(s) by which diabetes accelerates atherosclerosis has not been elucidated, several lines of evidence point to the role of increased inflammation in the pathogenesis of these vasculopathies. The monocyte-macrophage is a pivotal cell in atherogenesis and is readily accessible for study. However, there is scanty data on monocyte function and inflammation in T1DM. Simvastatin, a HMG-CoA reductase inhibitor, has recently been shown to reduce cardiovascular events in diabetic patients (T1DM and T2DM in the Heart Protection Study). Recent studies demonstrate that simvastatin decreased C-reactive protein and decreased pro-atherogenic activity of monocytes in non-diabetic subjects. However, there is a paucity of data on the effect of simvastatin on inflammation and monocyte function in Type 1 diabetes. Thus, the purpose of this study is Aim 1) to assess biomarkers of inflammation in T1DM compared to matched controls (n=50/group). Aim 2) Also, we will assess the effect of simvastatin (20mg/day) therapy on inflammation and monocyte function in T1DM in a randomized, placebo-controlled, double blind trial. At baseline and post-therapy, fasting blood will be obtained for routine laboratories (including lipid profile, glucose, glycated hemoglobin), free fatty acid levels, biomarkers of inflammation \[high sensitive C-reactive protein, plasma soluble cell adhesion molecules (sVCAM,sICAM, sE-selectin and sP-selectin) , CD40 ligand, monocyte pro-atherogenic activity (superoxide anion, monocyte chemotactic protein-1, interleukin (IL)-1b, IL-6 and tumor necrosis factor-a release, adhesion to human aortic endothelium, CD40 expression)\] etc., and 24-hour urine for microalbumin