Omentin Plasma Levels and Gene Expression Are Decreased in Obesity

Abstract

Central obesity and the accumulation of visceral fat are risk factors for the development of type 2 diabetes and cardiovascular disease. Omentin is a protein expressed and secreted from visceral but not subcutaneous adipose tissue that increases insulin sensitivity in human adipocytes. To determine the impact of obesity-dependent insulin resistance on the regulation of two omentin isoforms, gene expression and plasma levels were measured in lean, overweight, and obese subjects. Omentin 1 was shown to be the major circulating isoform in human plasma. Lean subjects had significantly higher plasma omentin 1 levels than obese and overweight subjects. In addition, higher plasma omentin 1 levels were detected in women compared with men. Plasma omentin 1 levels were inversely correlated with BMI, waist circumference, leptin levels, and insulin resistance as measured by homeostasis model assessment and positively correlated with adiponectin and HDL levels. Both omentin 1 and omentin 2 gene expression were decreased with obesity and were highly correlated with each other in visceral adipose tissue. In summary, decreased omentin levels are associated with increasing obesity and insulin resistance. Therefore, omentin levels may be predictive of the metabolic consequences or co-morbidities associated with obesity.

Association of a fat-derived plasma protein omentin with carotid artery intima-media thickness in apparently healthy men

“…A previous report showed that gender difference is observed in circulating omentin concentration. 7 It has also been shown that carotid IMT is generally greater in men than in women. 14 Although it is well established that plaque thickness is a predictor of cardiovascular risk, 12 no plaque in carotid artery was observed in apparently healthy subjects in this study.…”

“…[4][5][6] Omentin is detectable in human plasma and is downregulated in subjects with obesity and type 2 diabetes. 7,8 Low levels of plasma omentin are also associated with insulin resistance and endothelial dysfunction. 9,10 Thus, it is conceivable that circulating omentin is associated with obesity-linked disorders.…”

Omentin-1, visfatin and adiponectin levels in relation to bone mineral density in Iranian postmenopausal women

“…Omentin-1 is a newly identified depot-specific adipokine in human adipose tissue that may modulate insulin sensitivity by its paracrine or endocrine functions [13].It was shown that omentin-1 levels were inversely correlated with measures of obesity and insulin resistance and positively correlated with adiponectin levels [15]. It was also reported that omentin-1 levels were lower in patients with metabolic syndrome than in controls [23].…”

“…Furthermore, omentin-1 enhances insulin action and Akt phosphorylation [14]; it is inversely related to obesity [15] and is down regulated by insulin and glucose [13]. In an in vitro study to investigate the effects of omentin-1 on bone metabolism, omentin-1 reduced osteoclast formation by stimulating OPG and inhibiting RANKL production in osteoblasts [16].…”

Common variants of SLAMF1 and ITLN1 on 1q21 are associated with type 2 diabetes in Indian population

“…32 Plasma levels of Intelectin 1 are inversely correlated with BMI, waist circumference and insulin resistance. 33 A study that investigated association of Val109Asp variant of ITLN1 with type 2 diabetes in Caucasians failed to detect the same. 34 On contrary, our analysis revealed association of rs1333062 in 3¢ flank region of ITLN1, which is in complete LD with Val109Asp of ITLN1 (D¢¼1.0 and r 2 ¼1.0 both for GIH (Gujarati Indians in Houston, Texas) and CEU (Utah residents with Northern and Western European ancestry from the CEPH collection) populations from HapMap data).…”