ITIH-5 Expression in Human Adipose Tissue Is Increased in Obesity

• Published in: Obesity (Silver Spring, Md.) Md.), 2012-04, Vol.20 (4), p.708-714
• Main Authors: Anveden, Åsa, Sjöholm, Kajsa, Jacobson, Peter, Palsdottir, Vilborg, Walley, Andrew J., Froguel, Philippe, Al‐Daghri, Nasser, McTernan, Philip G., Mejhert, Niklas, Arner, Peter, Sjöström, Lars, Carlsson, Lena M.S., Svensson, Per‐Arne
• Format: Article
• Language: English
• Subjects: Adipocytes - metabolism; Adult; Blotting, Western; Body fat; Body Mass Index; Cells, Cultured; Clinical Medicine; Diet, Reducing; Down-Regulation; Female; Humans; Klinisk medicin; Male; Medicin och hälsovetenskap; Middle Aged; Obesity - genetics; Obesity - metabolism; Oligonucleotide Array Sequence Analysis; Proteinase Inhibitory Proteins, Secretory - genetics; Proteinase Inhibitory Proteins, Secretory - metabolism; Real-Time Polymerase Chain Reaction; RNA, Messenger - metabolism; Subcutaneous Fat - metabolism; Subcutaneous Fat - pathology; Weight Loss
• ISSN: 1930-7381; 1930-739X; 1930-739X
• DOI: 10.1038/oby.2011.268

Adipocytes secrete many proteins that regulate metabolic functions. The gene inter‐α (globulin) inhibitor H5 (ITIH‐5) encodes a secreted protein and is known to be expressed abundantly in the placenta. However, using gene expression profiles data we observed high expression of ITIH‐5 in adipose tissue. The aim of this study was to test the hypothesis that ITIH‐5 is strongly expressed in human adipocytes and adipose tissue, and is related to obesity and clinical metabolic variables. ITIH‐5 adipose tissue mRNA expression was analyzed with DNA microarray and real‐time PCR, and its association with clinical variables was examined. ITIH‐5 protein expression was analyzed using western blot. ITIH‐5 mRNA expression was abundant in human adipose tissue, adipocytes, and placenta, and higher in subcutaneous (sc) compared to omental adipose tissue (P < 0.0001). ITIH‐5 mRNA and protein expression in sc adipose tissue were higher in obese compared to lean subjects (P < 0.0001 and P < 0.001, respectively). ITIH‐5 mRNA expression was reduced after diet‐induced weight loss (P < 0.0001). ITIH‐5 mRNA expression was associated with anthropometry and clinical metabolic variables. In conclusion, ITIH‐5 is highly expressed in sc adipose tissue, increased in obesity, down regulated after weight loss, and associated with measures of body size and metabolism. Together, this indicates that ITIH‐5 merits further investigation as a regulator of human metabolism.