Functional Status of Pancreatic α and β Cells in Type 2 Diabetes Mellitus Patients with Different Plasma Triglyceride Levels: A Retrospective Analysis

Abstract

Objective: To investigate the functional status of pancreatic α and β cells in Type 2 diabetes mellitus (T2DM) patients with different plasma triglyceride (TG) levels. TG levels can be prognostic markers for T2DM.

Methods: A total of 328 patients with T2DM were divided into three groups according to different TG levels: the TGL group: TG < 1.7 mmol/L; TGM group: 1.7 mmol/L ≤ TG < 2.3 mmol/L; and TGH group: TG ≥ 2.3 mmol/L. An oral glucose tolerance test (OGTT), insulin release test, and glucagon release test were performed in each patient. The changes of glucagon, glucagon/insulin ratio, early insulin secretion index (ΔI ₃₀/ΔG ₃₀), and area under the insulin curve (AUC_I) were compared among each group. Also, the correlations between glucagon and pancreatic β-cell function, glycosylated hemoglobin (HbA1c), and other indices were analyzed.

Results: With the increase of TG, the fasting and postprandial glucagon levels, the glucagon/insulin ratio, and the area under the glucagon curve (AUC_G) presented an increasing trend. The homeostasis model assessment of insulin resistance (HOMA-IR) of the TGH group was significantly increased compared to the TGL and TGM groups. In addition to the increase in TG levels, the insulin sensitivity index (ISI), homeostasis model assessment for β-cell function index (HOMA-β), ΔI ₃₀/ΔG ₃₀, and AUC_I displayed a reducing trend. Glucagon was negatively correlated with ΔI ₃₀/ΔG ₃₀, high-density lipoprotein (HDL), HOMA-β, body mass index (BMI), ISI, and AUC_I (P < 0.05) and positively correlated with fasting blood glucose (FPG), AUC_G, HOMA-IR, HbA1c, duration, TG, low-density lipoprotein (LDL), and total cholesterol (TC) (P < 0.05).

Conclusion: Hypertriglyceridemia aggravated the dysfunction of pancreatic α and β cells. A reasonable control of the TG level makes it easier for blood glucose to reach the standard.

Figure 1

Glucagon and glucagon/insulin before and after OGTT among patients with different HbA1c. TGL: TG < 1.7 mmol/L; TGM: TGM 1.7 ≤ TG < 2.3 mmol/L; and TGH: TG ≥ 2.3 mmol/L. ^∗P < 0.05 versus TCL; ^#P < 0.05 versus TCM.

Figure 2

Islet β-cell function and AUCG among patients with different HbA1c levels. TGL: TG < 1.7 mmol/L; TGM: TGM 1.7 ≤ TG < 2.3 mmol/L; and TGH: TG ≥ 2.3 mmol/L. AUC_G: area under the curve of glucose; ΔI₃₀/ΔG₃₀: ratio of insulin increment and glucose increment 30 min after glucose load; AUC_I: area under the curve of insulin; HOMA-β: homeostasis model assessment of β-cell function; HOMA-IR: homeostasis model assessment of insulin resistance index; and ISI: insulin sensitivity index. ^∗P < 0.05 versus TCL; ^#P < 0.05 versus TCM.