Glycemic reduction alters white blood cell counts and inflammatory gene expression in diabetes.

OBJECTIVE: Systemic inflammation contributes to cardiovascular disease in patients with type 2 diabetes, and elevated white blood cell (WBC) counts are an established risk factor. Our goal is to describe changes in WBCs and inflammatory markers after glycemic reductions in diabetes.

RESEARCH DESIGN AND METHODS: This study enrolled 63 subjects with poorly controlled diabetes, defined as hemoglobin A1c (HbA1c) ≥8% [64 mmol/mol]. Circulating granulocytes and mononuclear cells were separated by histopaque double-density protocol. Inflammatory markers from these isolated WBCs were assessed at baseline and after 3 months of medical management.

RESULTS: After 3 months, significant glycemic reduction, defined as a decrease in HbA1c ≥ 1.5%, occurred in 42 subjects. Fasting plasma glucose decreased by 47% (165.6 mg/dL), and HbA1c decreased from 10.2 ± 1.8 to 6.8 ± 0.9. Glycemic reductions were associated with a 9.4% decrease in total WBC counts, 10.96% decrease in neutrophils, and 21.74% decrease in monocytes. The mRNA levels of inflammatory markers from granulocytes and mononuclear cells decreased, including receptor for advanced glycation endproducts; S100 calcium binding proteins A8, A9, A12; krüppel-like factor 5; and IL-1. Also, circulating levels of IL-1β and C-reactive protein decreased. Insulin dose was a mediator between HbA1c and both total WBC and neutrophil counts, but not changes in WBC inflammatory markers. In contrast, the 17 subjects without significant glycemic reductions showed no significant differences in their WBC counts and proteins of inflammatory genes.

CONCLUSION: Significant glycemic reduction in subjects with poorly controlled diabetes led to reduced circulating WBC counts and inflammatory gene expression.