Associations among SPARC mRNA expression in adipose tissue, serum SPARC concentration and metabolicparameters in Korean women

Objective: Secreted protein acidic and rich in cysteine (SPARC) is expressed in most tissues and is also secreted by adipocytes. The associations of SPARC mRNA expression in visceral adipose tissue (VAT), subcutaneous abdominal adipose tissue (SAT), serum SPARC concentration, and metabolic parameters in Korean women are investigated.

Design and Methods: This is a cross-sectional study. Fifty-eight women were recruited, of whom 15 women who underwent bariatric surgery for morbid obesity (BMI mean ± SD: 40.2±5.7 kg/m2), 16 who underwent metabolic surgery for type 2 diabetes (BMI: 28.9±4.5 kg/m2), and, as a control group, 27 who underwent gynecological surgery (BMI: 22.7±2.4 kg/m2). Anthropometric variables, metabolic parameters, SPARC mRNA expression in adipose tissue, and serum SPARC concentration were measured.

Results: In all subjects, SPARC mRNA expression was significantly higher in SAT than in VAT. Serum SPARC concentrations (mean ± SE) in morbidly obese subjects, subjects with type 2 diabetes, and normal weight subjects were 267.3±40.2 ng/mL, 130.4±33.0 ng/mL, and 53.1±2.8 ng/mL, respectively. SPARC mRNA in SAT was significantly correlated with BMI, whereas SPARC mRNA in VAT was significantly correlated with BMI and VAT area. Serum SPARC concentration was significantly correlated with BMI, waist circumference, total adipose tissue area, and SAT area. After BMI adjustment, serum SPARC concentration was significantly correlated with fasting insulin concentration and HOMA-IR score. Multivariate regression analysis showed that BMI and HOMA-IR were independently associated with serum SPARC concentration.

Conclusions: Serum SPARC concentration is significantly correlated with obesity indices and might be influenced by insulin resistance. These findings suggest that SPARC may contribute to the metabolic dysregulation associated with obesity in humans.

Lee SH et al. Obesity (Silver Spring). 2013 Nov;21(11):2296-302. doi: 10.1002/oby.20183. Epub 2013 May 13.

Human SPARC ELISA Kit SK00766-06 was used by Dr. Lee YJ on following paer.

Serum SPARC and matrix metalloproteinase-2 and metalloproteinase-9 concentrations after bariatric surgery inobese adults

Background Remodeling of the extracellular matrix (ECM) of adipose tissue is regarded as part of the pathophysiology of obesity. Secreted protein acidic and rich in cysteine (SPARC) was the first ECM protein described in adipose tissue. Matrix metalloproteinases (MMPs) also play a role in ECM remodeling, and MMP-2 and MMP-9 may be associated with abnormal ECM metabolism. Here, we investigated changes in serum SPARC, MMP-2, and MMP-9 concentrations after bariatric surgery in obese adults. Methods We recruited 34 obese patients who were scheduled to undergo bariatric surgery for weight loss. We analyzed changes in serum SPARC, MMP-2, and MMP-9 concentrations before and 9 months after bariatric surgery and any associations between changes in SPARC, MMP-2, and MMP-9 concentrations and obesity-related parameters. Results Serum leptin levels significantly decreased, and the serum adiponectin level significantly increased after bariatric surgery. The serum SPARC concentration decreased significantly from 165.0 ± 18.2 to 68.7 ± 6.7 ng/mL (p< 0.001), and the MMP-2 concentration also decreased significantly from 262.2 ± 15.2 to 235.9 ± 10.5 ng/mL (p< 0.001). Changes in the serum SPARC concentration were significantly correlated with HOMA-IR changes, and changes in the serum MMP-9 concentration were found to inversely correlate with serum adiponectin changes. Conclusion These findings show that significant decreases in serum SPARC and MMP-2 concentrations occur after bariatric surgery. Our results thus suggest that weight loss via bariatric surgery could alter the ECM environment, and that these changes are related to certain metabolic changes.

Lee YJ et al. Obes Surg. 2014 Apr;24(4):604-10.

A novel myokine, secreted protein acidic and rich in cysteine (SPARC), suppresses colon tumorigenesis via regular exercise