Correlation analysis of monocyte subsets and insulin resistance considering fetuin-A involvement in patients with type 2 diabetes.

BACKGROUND: Fetuin-A is a multifunctional circulating glycoprotein that can induce insulin resistance. Lately, adipose tissue has gained prominence as an effector site of fetuin-A. Although fetuin-A-induced proinflammatory polarization and migration of macrophages plays a crucial role, it remains obscure whether monocyte subsets in circulation could simulate characteristics of macrophages in adipose tissues. This study aims to investigate the correlation between monocyte subsets with fetuin-A and its relevant insulin resistance. RESULTS: We evaluated serum fetuin-A levels in 107 patients with type 2 diabetes (T2D). Using flow cytometry, we classified monocyte subsets into three subtypes: (a) classical, CD14++CD16-; (b) intermediate, CD14++CD16+, the most proinflammatory one; (c) and nonclassical, CD14+CD16++. We assessed the insulin resistance by the homeostasis model assessment for insulin resistance (HOMA-IR) in 68 patients without insulin injections. We observed no correlation between fetuin-A levels and classical (ρ = - 0.005; P = 0.959), intermediate (ρ = 0.022; P = 0.826), and nonclassical monocyte counts (ρ = 0.063; P = 0.516), respectively. In addition, no significant correlation was found between log (HOMA-IR) and classical (ρ = 0.052; P = 0.688), intermediate (ρ = 0.054; P = 0.676), and nonclassical monocyte counts (ρ = 0.012; P = 0.353), respectively. However, serum fetuin-A levels showed positive correlation with log (HOMA-IR) (ρ = 0.340; P = 0.007). Multiple regression analyses revealed a significant relationship between fetuin-A and log (HOMA-IR) (ß = 0.313; P = 0.016), but not with monocyte subsets. CONCLUSIONS: Monocyte subsets in circulation, including proinflammatory intermediate monocytes, were not associated with fetuin-A and insulin resistance.

The Association between Monocyte Surface CD163 and Insulin Resistance in Patients with Type 2 Diabetes.

AIM: To investigate the association between monocyte CD163 and insulin resistance in patients with type 2 diabetes. METHODS: One hundred sixty-six patients with type 2 diabetes without inflammatory or chronic kidney disease were recruited. The monocyte CD163 levels were measured by flow cytometry and soluble CD163 (sCD163) by ELISA. Insulin resistance was evaluated by the index of the homeostasis model assessment (HOMA-R). RESULTS: The median sCD163 and monocyte CD163 expression levels were 582.9 (472.4-720.0) ng/ml and 6061 (4486-7876) mean fluorescent intensity (MFI), respectively. In a simple regression analysis, monocyte CD163 was inversely correlated with log [HOMA-R] (r = -0.257, p = 0.010), and sCD163 was positively correlated with log [HOMA-R] (r = 0.198, p = 0.042). In multiple regression analyses, monocyte CD163 was an independent contributor to log [HOMA-R] (ß = -0.220, p = 0.020) even after adjustment of various clinical factors for HOMA-R (R2 = 0.281, p = 0.001), whereas sCD163 was not. CONCLUSIONS: Monocyte surface CD163 expression levels were more significantly associated with insulin resistance than sCD163 in patients with type 2 diabetes, suggesting a novel pathophysiological role of CD163.

Plasma C1q/TNF-Related Protein-9 Levels Are Associated with Atherosclerosis in Patients with Type 2 Diabetes without Renal Dysfunction.

Aim. C1q/tumor necrosis factor-related protein-9 (CTRP9), a paralog of adiponectin, is expressed in adipose tissue. CTRP9 exerts protective effects against obesity and atherosclerosis in rodents. We investigated the association between plasma CTRP9 levels and atherosclerosis in patients with type 2 diabetes. Methods. We included 419 patients with type 2 diabetes, 161 of whom had chronic kidney disease (CKD). Fasting plasma CTRP9 and total adiponectin levels were measured with enzyme-linked immunosorbent assay. The intima-media thickness (IMT) of the common carotid artery was measured with ultrasonography. Results. Plasma CTRP9 levels were higher in the CKD group than in the non-CKD group. Plasma CTRP9 levels were positively correlated with carotid IMT in the non-CKD group. Multivariate analyses revealed that plasma CTRP9 levels were positively associated with carotid IMT in the non-CKD group, independent of age, sex, body mass index, adiponectin, and other cardiovascular risk factors. However, plasma CTRP9 levels were not associated with carotid IMT in the CKD group. Conclusion. Plasma CTRP9 levels are associated with atherosclerosis in diabetic patients without CKD, independently of obesity, adiponectin, and traditional cardiovascular risk factors. This study indicates a potential role of CTRP9 in atherosclerosis progression in human type 2 diabetes.