Validation of endogenous reference genes for qRT-PCR analysis of human visceral adipose samples

Cross-validation of expression stability of eight selected reference genes using three popular algorithms, GeNorm, NormFinder and BestKeeper found ACTB and RPII as most stable reference genes.We recommend ACTB and RPII as stable reference genes most suitable for gene expression studies of human visceral adipose tissue. The use of these genes as a reference pair may further enhance the robustness of qRT-PCR in this model system.The increasing prevalence of obesity worldwide has drawn research on adipose tissue into the spotlight. Adipose tissue is a complex and highly active tissue with important metabolic and endocrine functions. It not only plays a central role in energy balance but also functions as an endocrine organ secreting various adipokines and cytokines [1,2]. On the basis of its distribution, adipose tissue is divided into three main regions: subcutaneous, intramuscular and visceral fat [3,1].Accumulation of excessive visceral fat (visceral obesity) is associated with an array of metabolic perturbations including type 2 diabetes, insulin resistance, non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), cardiovascular disease, hypertension and hyperlipidemia together referred to as "metabolic syndrome" [4,5]. However, the role of visceral obesity in metabolic syndrome is yet to be fully elucidated [6]. Furthermore, a causal relationship between insulin resistance and metabolic syndrome has not been shown conclusively; Obesity seemingly causes insulin resistance, on the other hand insulin resistance appears to aggravate and propagate the adverse effects of obesity [7]. This somewhat co-dependent and circular relationship is difficult to untangle and has generated a multitude of clinical and research publications.Another area of disagreement involves NAFLD, a common condition affecting about 70% of obese and overweight individuals and increasingly being recognized as a major cause of liver-related morbidity and mortality [8]. The pa