Vitamin B2 deficiency enhances the pro-inflammatory activity of adipocyte, consequences for insulin resistance and metabolic syndrome development.

AIMS: Adipose tissue is an endocrine organ important for regulation of such physiological processes as energy metabolism or lipids homeostasis. In an obesity state, it participates in the induction of chronic systemic inflammation accompanied by pro-inflammatory cytokines and fatty acid elevation. For this reasons, adipose tissue is involved in, e.g., insulin resistance, type 2 diabetes or hyperlipidemia development. In our previous study, we have shown that riboflavin deficiency induces a pathological pro-inflammatory response of macrophages, the main component of adipose tissue. Therefore, in the current study, we investigated the alteration of the pro-inflammatory activity of adipocytes.

MAIN METHODS: The study was conducted on mouse 3T3 L1 preadipocytes differentiated to adipocyte and culture in the state of riboflavin deficiency (3.1nM) or control condition (10.4nM). The cell viability, adiposity and glucose uptake was assessed. Moreover, mRNA expression, as well as crucial pro-inflammatory cytokines (TNFα, IL-6) and adipokines (adiponectin, leptin, resistin) release and NFκB activation, were evaluated.

KEY FINDINGS: Results showed that riboflavin deprivation induced a significant elevation in adipocyte lipolysis and enhance obesity-related apoptosis of adipocytes. The generation of reactive oxygen species was enhanced in riboflavin-deficient adipocytes by 43%. Moreover, NFκB phosphorylation and the expression and release of both TNFα, IL-6 as well as leptin were elevated in a deficient group what was accompanied by a reduction of adiponectin level.

CONCLUSION: Our study shows that riboflavin deficiency can promote the intensification of pro-inflammatory activity of adipocyte cells, leading consequently to the severity of chronic inflammation that accompanies obesity state.