The Relationship Between Brown Adipose Tissue Content in Supraclavicular Fat Depots and Insulin Sensitivity in Patients with Type 2 Diabetes Mellitus and Prediabetes

Abstract

Background: The evaluation of brown adipose tissue (BAT) and its role in metabolism and obesity remains an important topic in the recent literature. This study evaluated the influence of the BAT triglyceride content measured by proton magnetic resonance (MR) spectroscopy in patients with type 2 diabetes mellitus (DM2) and prediabetes on insulin sensitivity.

Methods: A total of 25 patients with DM2 and prediabetes (45.9 ± 10.1 years old, body mass index [BMI] of 31.6 ± 5.4 kg/m²) underwent anthropometric measurements (BMI), insulin sensitivity analysis (M value during euglycemic hyperinsulinemic clamp and homeostasis model assessment of insulin resistance), proton MR spectroscopy, and blood tests (total cholesterol, low-density lipoproteins, high-density lipoproteins, and triglycerides). The relationship between the triglyceride content in the supraclavicular fat depot and insulin sensitivity, anthropometric measurements, and blood test results was assessed.

Results: The triglyceride content in the supraclavicular fat depot varied between 79.2% and 97.1% (mean: 92.6% ± 4.2%). The triglyceride content in the subcutaneous white adipose tissue of the neck was significantly higher (85.3%-99.3%; mean: 95.5% ± 2.9%; P = 0.0007). The triglyceride content in the supraclavicular fat depot exhibited a significantly moderate correlation with the BMI (r = 0.64; P = 0.0009). A significant weak negative correlation between the supraclavicular fat content and M value was revealed (r = -0.44; P = 0.002). Patients with high insulin resistance (IR) had a higher triglyceride content in the supraclavicular fat depot than patients with normal and lower IR (94.3% ± 2.0% vs. 90.4% ± 5.2%; P = 0.02).

Conclusions: Reducing the BAT content in the supraclavicular fat depot can influence the development of IR in patients with DM2 and prediabetes.

Keywords: Brown adipose tissue; Insulin sensitivity; M value; MR spectroscopy; Type 2 diabetes mellitus; White adipose tissue.

FIG. 1.

Volumes positioning for MR spectroscopy in the left supraclavicular fat depot (A, B) and in the subcutaneous WAT of the neck (C, D). MR, magnetic resonance; WAT, white adipose tissue.

FIG. 2.

MR spectra of fat tissue in the left supraclavicular fat depot (A) and the subcutaneous WAT of the neck (B), triglyceride content = 93% and 98% respectively. The major peaks of fat tissue and water are shown.

FIG. 3.

Significant correlation of the triglyceride content in supraclavicular fat depot with body mass index (A) and M-value (B) was revealed. Dotted lines indicate 95% confidence intervals.

FIG. 4.

MR spectra of fat tissue in the left supraclavicular fat depot in the patient with normal and low degree of insulin resistance, M value = 7.0 mg/kg/min, left supraclavicular triglyceride content = 79.2% (A) and in the patient with high degree of insulin resistance, M value = 2.46 mg/kg/min, left supraclavicular triglyceride content = 96.6% (B). The major peaks of fat tissue and water are shown.