Differential gene expression in the adipose tissue of morbidly obese patients includes genes related to lipid and glucose metabolism, membrane transport, and genes promoting the cell cycle. These findings are a first step toward clarifying the molecular pathogenesis of obesity and identifying potential targets for therapeutic intervention.

Obese patients with insulin resistance have decreased serum adiponectin and increased serum resistin. Additionally, adiponectin gene expression is also decreased in the adipose tissue of these patients. This low level of adiponectin expression may predispose patients to the progressive form of NAFLD or NASH.

Our findings support the hypothesis that adipocyte secretion plays an important role in the development of NAFLD.

The recent development of high-throughput gene expression technology permits simultaneous investigation of thousands of genes, providing a snapshot of the transcription state of diseased tissue. Microarray-based expression profiling is well suited to investigate the molecular basis of complex diseases such as obesity and chronic liver disease. With the help of microarray technology, functional genomics will surely advance our understanding of these diseases, and lead to more effective, targeted interventions that lack the toxicity of many conventional treatments. Despite their tremendous potential, microarray studies are subject to potential flaws in experimental design, experimental techniques, data analysis, and data interpretation. Besides the technical issues, the most important challenge is to develop integrative databases that combine gene expression data with the clinical data. Over the next few years, advances in technology and refinements in study design and data analysis will make clinically relevant translational research even more engaging and productive.