Serum Isthmin-1 is negatively correlated with HDL-C in type 2 diabetes mellitus

Isthmin-1 (Ism-1) is a newly identified insulin-like adipokine that increases glucose uptake by adipocytes and inhibits hepatic lipid synthesis. Recent studies have shown that Ism-1 can improve the metabolic disorders associated with type 2 diabetes mellitus (T2DM) and improve lipid metabolism. The classic function of high-density lipoprotein cholesterol (HDL-C) is to transport cholesterol from extra-hepatic tissues to the liver for metabolism. In contrast, disorders of lipid metabolism and inflammation are the leading causes of atherosclerosis (As). Atherosclerosis often manifests as loss of elasticity, lipid accumulation, fibrous tissue proliferation and calcium deposits in the affected arteries, eventually forming plaques.

To illustrate the correlation between HDL-C and Ism-1 in T2DM, and the relationship between lipoprotein cholesterol and carotid plaque.

A total of 128 patients with T2DM were enrolled in the study and basic information was collected. HDL-C levels were measured chemically. Serum Ism-1 levels were measured using an enzyme-linked immunosorbent assay (ELISA). Linear regression analysis was used to assess the correlation between serum Ism-1 levels and HDL-C in patients with T2DM. Basic information was again collected from 226 patients with T2DM. Independent sample t-tests were performed to explore the relationship between carotid plaque formation and lipids.

HDL-C was divided into four groups according to quartiles and there was a between-group difference in Ism-1 (p = 0.040). Multivariable linear regression showed a negative association between Ism-1 and HDL-C in T2DM (β = -0.235, p < 0.001), even after adjusting for related factors (β = -0.165, p = 0.009). Low-density lipoprotein cholesterol (LDL-C) and HDL-C showed significant differences between the carotid plaque group and the non-carotid plaque group (p_LDL-C = 0.007, p_HDL-C = 0.003).

Serum Ism-1 and HDL-C are negatively correlated in T2DM. LDL-C is significantly higher in carotid plaque group than non-carotid plaque group, while HDL-C is significantly lower than in the non-carotid plaque group.