Elevated plasma levels of SPARC in patients with newly diagnosed type 2 diabetes mellitus.

OBJECTIVE: Secreted protein acidic and rich in cysteine (SPARC) also known as BM-40 which has been studied in various pathological conditions, has recently been suggested as a key player in the pathology of obesity and type 2 diabetes mellitus (T2DM). However, there are few studies on putative pathophysiologic roles of SPARC in glucose metabolism. The aim of this study was to determine whether plasma SPARC concentrations were altered in subjects with different glucose metabolic conditions and to investigate the affecting factors. DESIGN AND METHODS: In this study, 54 newly diagnosed T2DM subjects, 53 subjects with impaired glucose regulation (IGR), and 53 normal subjects (body mass index (BMI): 24.98 ± 3.75 vs 24.70 ± 2.78 and 24.53 ± 3.66 kg/m(2), P>0.05) were enrolled. Plasma SPARC levels were measured with an ELISA under overnight fasting conditions. The relationships between plasma SPARC and several metabolic factors, such as BMI, blood lipids, blood glucose, plasma insulin levels, and other factors were also assessed. Results SPARC levels were higher in subjects with T2DM compared with IGR and control subjects (16.74 ± 6.99 vs 14.04 ± 8.03 μg/l, P<0.05 and 16.74 ± 6.99 vs 11.72 ± 4.47 μg/l, P<0.01). However, there was no difference in plasma SPARC levels between IGR subjects and the controls. Plasma SPARC levels correlated positively with BMI, the percentage of fat, triglyceride, fasting plasma insulin, 2 h plasma insulin after a glucose load, and the homeostasis model assessment of insulin resistance in simple regression analysis.
CONCLUSION: The present work indicates a potential link between SPARC and the pathogenesis of T2DM.