Associations between circulating levels of FABP4 and TNF receptors are more evident in patients with type 2 diabetes mellitus than in patients with type 1 diabetes mellitus.

Background: Fatty acid-binding protein 4 (FABP4) is an adipokine that plays significant roles in the development of insulin resistance and atherosclerosis. High levels of soluble tumor necrosis factor receptors (TNFRs) including TNFR1 and TNFR2 are associated with renal dysfunction and increased mortality in patients with diabetes mellitus (DM). However, the association between circulating levels of FABP4 and TNFRs remains unclear.

Methods: We investigated the associations of FABP4 with TNFRs and metabolic markers in Japanese patients with type 1 DM (T1DM, n = 76, men/women: 31/45) and type 2 DM (T2DM, n = 575, men/women: 312/263).

Results: FABP4 concentration was positively correlated with levels of TNFR1 and TNFR2 in both patients with T1DM and those with T2DM. Multivariable regression analyses showed that there were independent associations of FABP4 concentration with body mass index (BMI) and estimated glomerular filtration rate (eGFR) after adjustment for age and sex in both patients with T1DM and those with T2DM. FABP4 concentration was independently associated with circulating levels of TNFR1 and TNFR2 after adjustment for the confounders in patients with T2DM but not in those with T1DM. Similarly, levels of TNFR1 and TNFR2 were independently associated with FABP4 concentration after adjustment for age, sex, systolic blood pressure, duration of DM and levels of eGFR, high-density lipoprotein cholesterol, and C-reactive protein in patients with T2DM but not in those with T1DM.

Conclusion: FABP4 concentration is independently associated with levels of TNFRs in patients with DM, but the association is more evident in patients with T2DM than in those with T1DM.