Circulating Complement-C1q TNF-Related Protein 1 Levels Are Increased in Patients with Type 2 Diabetes and Are Associated with Insulin Sensitivity in Chinese Subjects

Abstract

BackgroundComplement-C1q TNF-related protein 1 (CTRP1), a member of the CTRP superfamily, possesses anti-inflammatory and anti-diabetic effects in mice. However, the clinical relevance of CTRP1 has been seldom explored. The current study aimed to investigate the association of circulating CTRP1 and type 2 diabetes mellitus (T2DM) in a Chinese population.Design and MethodsSerum CTRP1 and adiponectin levels of 96 T2DM patients and 85 healthy subjects were determined by ELISA, and their associations with adiposity, glucose and lipid profiles were studied. In a subgroup of this study, the 75-g oral glucose tolerance test (OGTT) was performed in 20 healthy and 20 T2DM subjects to evaluate the relationship among serum levels of CTRP1 and adiponectin, insulin secretion and insulin sensitivity.ResultsSerum CTRP1 levels were significantly increased in patients with T2DM, compared with healthy controls (p<0.001). Similar to adiponectin, serum levels of CTRP1 were significantly correlated to several parameters involved in glucose metabolism and insulin resistance, and independently associated with fasting glucose levels (p<0.05) after BMI and gender adjustments. Furthermore, CTRP1 levels were positively correlated to insulin secretion, while negatively to insulin sensitivity, as measured by OGTT.ConclusionCTRP1 is a novel adipokine associated with T2DM in humans. The paradoxical increase of serum CTRP1 levels in T2DM subjects may be due to a compensatory response to the adverse glucose and lipid metabolism, which warrants further investigation.

The Circulating CTRP13 in Type 2 Diabetes and Non-Alcoholic Fatty Liver Patients

“…It worth also mentioning that our data is inconsistent with some investigations that indicated the high plasma level of CTRP1 in NAFLD and T2DM [10]. This might be a possible explanation for the compensatory role of CTRP1 which increased in coronary artery disease and T2DM patients [15–17]. …”

C1q/TNF‐related protein‐1 functions to protect against acute ischemic injury in the heart

“…It has been shown that CTRP1 displays insulin-sensitizing effects (8,14). Clinical evidence has shown that circulating CTRP1 levels are increased in association with metabolic syndrome, type 2 diabetes, and ischemic heart disease (10)(11)(12)(13). Given that most adipokines with protective cardiometabolic effects, including adiponectin, are downregulated by obesity (4,16,38), CTRP1 may serve as a unique adipokine that is up-regulated by the complications of obesity, presumably as a compensatory response to mitigate metabolic and cardiac disorders.…”

“…It is up-regulated in adipose tissue in diabetic rats, and its expression is stimulated by proinflammatory cytokines (9). Clinical evidence has shown that high levels of circulating CTRP1 are associated with metabolic syndrome and type 2 diabetes (10)(11)(12). In a recent study, we demonstrated that plasma CTRP1 levels are increased in patients with coronary artery disease (13).…”

CTRP1: A Molecular Link between Obesity and Hypertension

“…Serum CTRP1 levels were significantly increased in patients with T2DM [19,20] and plasma Aldosterone concentration is elevated in patients with diabetes mellitus [15]. Study group with diabetic nephropathy was selected because DN is associated with hypertension.…”