Increased mRNA Expression of CTRP3 and CTRP9 in Adipose Tissue from Obese Women: Is it Linked to Obesity-Related Parameters and mRNA Expression of Inflammatory Cytokines?

Abstract

Background: Obesity, a medical condition with impaired adipokine secretion and function, has a detrimental effect on insulin and glucose metabolism. CTRP3 and CTRP9 are adipokines with possible roles in energy homeostasis regulation. We sought to compare CTRP3, CTRP9, and inflammatory gene expression in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) from obese women who underwent bariatric surgery and non-obese women as controls.

Methods: For this study, the investigators recruited 20 morbidly obese women (BMI> 35) who qualified for bariatric surgery and 20 normal-weight women (BMI< 25) who underwent elective surgeries. Real-time PCR was performed to investigate mRNA expression of CTRP3, CTRP9, and the inflammatory genes IL1-β, IL-6, MCP-1, and TNF-α in SAT and VAT from both obese patients and controls.

Results: We observed that CTRP3 mRNA levels were significantly greater in VAT from obese patients than from controls (P< 0.0003). Also, patient group had higher levels of CTRP9 that control group (P< 0.0026). Inflammatory cytokines were markedly increased in SAT of obese patients compared to controls (P< 0.05). In addition, our results revealed a positive correlation of CTRP9 with HOMA-IR and waist circumference in VAT and CTRP3 with IL-1β, MCP-1, and TNF-α in SAT.

Conclusion: Both CTRP3 and CTRP9 expression were significantly higher in VAT from obese patients than from controls, and CTRP3 expression positively correlated with inflammatory parameters. Our findings indicate that CTRP3 and CTRP9 might be important in regulating glucose metabolism and obesity-related conditions such as inflammation.

Keywords: Adipokine; CTRP3; CTRP9; Obese women; Obesity.

Fig. 1

Relative C1q/TNF-related protein-3 (CTRP3) and CTRP9 mRNA expression in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) samples from the control and patient groups. (a) CTRP3 expression was significantly greater in VAT from patients than from controls (p= 0.0003); (b) No significant difference in CTRP3 expression in SAT was seen between the two groups (p= 0.2087); (c) CTRP9 expression was significantly greater in VAT from patients than from controls (p= 0.0026); (d) No significant difference in CTRP9 expression in SAT was seen between the two groups (p= 0.0902). *The relative gene expression levels were presented as 2- ΔΔCT and gene expression data were transformed log 2 scale to approximate a normal distribution. **p< 0.05 indicates significant differences.

Fig. 2

Relative interleukin (IL)-1β and monocyte chemoattractant protein 1 (MCP-1) inflammatory cytokines expression in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) from the control and patient groups. (a) IL-1β expression was significantly greater in VAT from patients than from controls (p= 0.015); (b) No significant difference in IL-1β expression in SAT was seen between the two groups (p= 0.0737); (c and d) MCP-1 expression was significantly greater in VAT and SAT from patients than from controls (p= 0.0013 and 0.005, respectively). *The relative gene expression levels were presented as 2- ΔΔCT and gene expression data were transformed log 2 scale to approximate a normal distribution. **p< 0.05 indicates significant differences.

Fig. 3

Relative interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α) in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) samples from the control and patient groups. (a, b) IL-6 expression was significantly greater in VAT and SAT from patients than from controls (p= 0.0001 and 0.013, respectively); (c) TNF-α expression was significantly greater in VAT from patients than from controls (p= 0.0141); (d) No significant difference in TNF-α expression in SAT was seen between the two groups (p= 0.346). *The relative gene expression levels were presented as 2- ΔΔCT and gene expression data were transformed log 2 scale to approximate a normal distribution. **p< 0.05 indicates significant differences.