Obesity is associated with chronic low-grade
inflammation, which contributes to systemic metabolic irregularities and
obesity-linked metabolic disorders.
Orosomucoid (ORM), an
acute phase reactant protein, was shown to be produced in response to metabolic and inflammatory signals in the adipose tissue of obese mice, which protects them from severe
inflammation and subsequent metabolic dysfunction. In this study, we examined whether there are site-specific differences between visceral and subcutaneous adipose tissue (VAT and SAT, respectively) ORM gene and
protein expression from individuals with a wide range of
obesity and the relationship between expressed and circulating ORM levels and measures of adiposity,
insulin resistance, and pro- and anti-inflammatory markers and
adipokines. The level of circulating ORM correlated positively with BMI, body fat mass, and serum
leptin. It also correlated with fasting
insulin, HOMA-IR values and
C-reactive protein in men. There were no site-specific differences in ORM
mRNA and
protein expression between VAT and SAT, nor did we find a relationship between circulating ORM levels and its
mRNA expression in either fat depot. We found that ORM
mRNA expression correlated with
mRNA expression of TNF-α,
IL-6, and
adiponectin in VAT, and with TNF-α and
adiponectin in SAT. These observations are the first description linking adipose tissue ORM and pro- and anti-inflammatory molecules in humans. The close links of ORM and measures of adiposity,
insulin resistance, and adipose tissue
inflammation in humans reinforce previous experimental data and warrant further studies to explore a possible role of ORM in the pathogenesis of
obesity-associated metabolic derangements.