Vaspin

Is an adipocytokine, designated as visceral adipose tissue-derived serpin (vaspin), which is a member of serine protease inhibitor family. Vaspin cDNA was isolated by from visceral white adipose tissues (WATs) of Otsuka Long- Evans Tokushima fatty (OLETF) rat, an animal model of abdominal obesity with type 2 diabetes. Rat, mouse, and human vaspins are made up of 392, 394, and 395 amino acids, respectively; exhibit approximately 40% homology with alpha1-antitrypsin; and are related to serine protease inhibitor family.

Vaspin Expression

Vaspin was barely detectable in rats at 6 wk and was highly expressed in adipocytes of visceral WATs at 30 wk, the age when obesity, body weight, and insulin levels peak in OLETF rats. The tissue expression of vaspin and its serum levels decrease with worsening of diabetes and body weight loss at 50 wk.

Vaspin regulation

The expression and serum levels were normalized with the treatment of insulin or insulin-sensitizing agent, pioglitazone.

Vaspin action

Administration of vaspin to obese CRL:CD-1 (ICR) mice fed with high-fat highsucrose chow improved glucose tolerance and insulin sensitivity reflected by normalized serum glucose levels. It also led to the reversal of altered expression of genes relevant to insulin resistance, e.g., leptin, resistin, TNFalpha, glucose transporter-4, and adiponectin. In DNA chip analyses, vaspin treatment resulted in the reversal of expression in approximately 50% of the high-fat high- sucrose-induced genes in WATs. These findings indicate that vaspin exerts an insulin-sensitizing effect targeted toward WATs in states of obesity.

Vaspin in Humans

Visceral vaspin expression significantly correlates with BMI, % body fat, and 2 h OGTT plasma glucose. Subcutaneous vaspin mRNA expression is significantly correlated with waist:hip ratio (WHR), fasting plasma insulin concentration, and glucose infusion rate during steady state of an euglycemichype­rinsulinemic clamp. Multivariate linear regression analysis revealed % body fat as strongest predictor of visceral vaspin and insulin sensitivity as strongest determinant of subcutaneous vaspin mRNA expression. In conclusion, these data indicate that induction of human vaspin mRNA expression in adipose tissue is regulated in a fat depot-specific manner and could be associated with parameters of obesity, insulin resistance, and glucose metabolism.

Vaspin in Circulation

Circulating vaspin was found to be significantly lower in males as compared with females and was decreased in insulin-treated subjects. In univariate analyses, vaspin levels positively correlated with age and high-density lipoprotein cholesterol and negatively with waist-to-hip ratio and GFR in control patients, whereas the adipokine was negatively associated with glomerular filtration rate (GFR) and C-reactive protein (CRP) in chronique dialysis (CD) patients. In multivariate analyses, age and gender were independently associated with vaspin in controls, whereas gender, GFR, and CRP independently predicted circulating vaspin in CD patiens.

Another study found no difference in circulating vaspin between individuals with normal glucose tolerance (NGT) and T2D. In the NGT group, circulating vaspin significantly correlated with BMI and insulin sensitivity.

Physical training for 4 weeks resulted in significantly increased circulating vaspin levels. Low circulating vaspin correlates with a high fitness level, whereas physical training in untrained individuals causes increased vaspin serum concentrations.

Catalog Number	Protein	Source	Size
RD172097100	Vaspin (Serpin A12, Visceral adipose-specific serpin) Human (E. coli)	E. coli	0.1 mg
RD172097100+	Vaspin (Serpin A12, Visceral adipose-specific serpin) Human (E. coli)	E. coli	10 x 0.1 mg