SIRT1 Serum Concentrations in Lipodystrophic Syndromes

Abstract

Lipodystrophies (LDs) are rare, complex disorders of the adipose tissue characterized by selective fat loss, altered adipokine profile and metabolic impairment. Sirtuins (SIRTs) are class III NAD⁺-dependent histone deacetylases linked to fat metabolism. SIRT1 plays a critical role in metabolic health by deacetylating target proteins in tissue types including liver, muscle, and adipose. Circulating SIRT1 levels have been found to be reduced in obesity and increased in anorexia nervosa and patients experiencing weight loss. We evaluated circulating SIRT1 levels in relation to fat levels in 32 lipodystrophic patients affected by congenital or acquired LDs compared to non-LD subjects (24 with anorexia nervosa, 22 normal weight, and 24 with obesity). SIRT1 serum levels were higher in LDs than normal weight subjects (mean ± SEM 4.18 ± 0.48 vs. 2.59 ± 0.20 ng/mL) and subjects with obesity (1.7 ± 0.39 ng/mL), whereas they were close to those measured in anorexia nervosa (3.44 ± 0.46 ng/mL). Our findings show that within the LD group, there was no relationship between SIRT1 levels and the amount of body fat. The mechanisms responsible for secretion and regulation of SIRT1 in LD deserve further investigation.

Keywords: SIRT1; adipokines; adipose tissue; lipodystrophy.

Figure 1

Correlation between fat percentage in the whole body and SIRT1 serum concentrations in patients with different subtypes of LD: generalized lipodystrophy (GL, n = 3), progeroid syndromes (PS, n = 5), familial partial lipodystrophy type 1 (FPLD1, n = 4), familial partial lipodystrophy type 2 (FPLD2, n = 7), and acquired partial lipodystrophy (APL, n = 10). r² = 0.002489, p = 0.79.

Figure 2

Comparison of SIRT1 serum concentrations in patients with lipodystrophies (LD, n = 32), anorexia nervosa (AN, n = 24), obesity (OB, n = 24) and normal weight subjects (NW, n = 22). Values are expressed as means ± standard error (SEM). * p < 0.05.