Expression analysis of MMP14: Key enzyme action in modulating visceral adipose tissue plasticity in patients with obesity.

Compromised adipose tissue plasticity is a hallmark finding of obesity orchestrated by the intricate interplay between various extracellular matrix components. Collagen6 (COL6) is well characterized in obese visceral adipose tissue (VAT), not much is known about MMP14 which is hypothesized to be the key player in matrix reorganization. Subjects with obesity (BMI ≥40; n = 50) aged 18-60 years undergoing bariatric surgery and their age-matched controls (BMI < 25; n = 30) were included. MMP14, Col6A3 and Tissue inhibitor of metalloproteinase 2 (TIMP2) mRNA expression was assessed in VAT and their serum levels along with endotrophin were estimated in both groups preoperatively and post-operatively in the obese group. The results were analysed statistically and correlated with anthropometric and glycaemic parameters, namely fasting glucose and insulin, HbA1c, HOMA-IR, HOMA-ß and QUICKI. Circulating levels as well as mRNA expression profiling revealed significant differences between the individuals with and without obesity (p < .05), more so in individuals with diabetes and obesity (p < .05). Follow-up serum analysis revealed significantly raised MMP14 (p < .001), with decreased Col6A3, endotrophin and TIMP2 levels (p < .01, p < .001 and p < .01, respectively). A rise in serum MMP14 protein, simultaneous with post-surgical weight loss and decreased serum levels of associated extracellular matrix (ECM) remodellers, suggests its crucial role in modulating obesity-associated ECM fibrosis and pliability of VAT.

An immediate post op and follow up assessment of circulating adipo-cytokines after bariatric surgery in morbid obesity.

BACKGROUND: Bariatric surgery has emerged as a promising treatment for improving adipose tissue dysfunction in obesity, but the mechanisms for such amelioration are still not known. This study comprehensively explores a panel of adipo-cytokines in individuals with obesity undergoing bariatric surgery, in conjunction with markers of insulin resistance, at three time points i.e., pre-op, immediate post-op and 6 months post-surgery. METHODS: It is a case-control prospective study among obese individuals undergoing bariatric surgery (BMI ≥35 kg/m2, n=30) and non-obese subjects (BMI <25 kg/m2, n=30), comparing the levels of serum adiponectin, resistin, C-Reactive Protein (CRP), Interleukin (IL)-6 and 8, Monocyte chemoattractant protein (MCP)-1 and Tumor necrosis factor (TNF)-α between them. The same were followed at immediate and 6-month post-op periods in the former group. The serum markers were correlated with the markers of Insulin resistance like HOMA-IR, HOMA-ß and QUICKI. RESULTS: A significant increase in adiponectin was seen after weight loss in obese group (17.54 ± 1.31 µg/mL at baseline vs 68.76 ± 1.84 µg/mL at 6- month post-surgery). CRP being an acute phase protein showed significant higher levels at immediate post-op period but declined even below its baseline at 6 months after surgery (33.34 ± 16.85 µg/mL at baseline vs 59.85 ± 23.12 µg/mL at immediate post-op vs 9.66 ± 1.84 µg/mL at 6 months post-operatively). Few inconsistencies were observed in the trajectories of IL-6 and TNF-α, while other pro-inflammatory markers indicated resolution after surgery. CONCLUSION: Bariatric surgery alleviated the systemic inflammation, correlating with improved insulin resistance in individuals with obesity.

Serum Adipocytokines Levels and Their Association with Insulin Sensitivity in Morbidly Obese Individuals Undergoing Bariatric Surgery.

BACKGROUND: Obese adipose tissue secretes a variety of adipocytokines that act as metabolic regulators with complex mechanisms. Our objective was to compare serum concentration of a panel of adipocytokines between obese and non-obese individuals and identify any distinct patterns correlating with insulin sensitivity in obesity. METHODS: We designed a cross-sectional study among obese (body mass index [BMI] ≥30 kg/m2, n=62) and non-obese (BMI <25 kg/m2, n=32) individuals to compare circulating levels of the adipokines, such as adiponectin and resistin in conjunction with the measurement of the levels of inflammatory cytokines including C-reactive protein (CRP), interleukin (IL)-6, IL-8, monocyte chemoattractant protein (MCP)-1, and tumor necrosis factor (TNF)-α using Luminex multiplex immunoassay with drop array technology. Correlations between circulating adipocytokine levels and those of multiple well-established markers of insulin resistance including homeostatic model assessment of insulin resistance (HOMA-IR), homeostatic model assessment of ß-cell function (HOMA-ß) and quantitative insulin sensitivity check index were also established. RESULTS: CRP, IL-8, MCP-1, and TNF-α levels were higher in obese than non-obese individuals; the CRP and IL-8 differences were statistically significant. CRP correlated significantly with markers of insulin resistance (fasting plasma insulin, HOMA-IR, and QUICKI), and adiponectin correlated with HOMA-ß in obese individuals. We divided the group of obese individuals on the basis of HOMA-IR levels into insulin-resistant (IR; HOMA-IR ≥2.5) and insulin-sensitive (IS; HOMA-IR <2.5) groups; and 43 out of 62 participants were IR despite comparable BMIs. An overall proinflammatory profile was compared between IR and IS obese, though the values were higher in IR obese but the difference was not significant. CONCLUSION: Obesity is associated with a general inflammatory milieu and a crosstalk between adipocytokines and insulin resistance is complex as well as multifactorial.