Endocrine Abstracts (2012) 28 P176

Expression of genes regulating mitochondrial fusion and fission in human adipose tissue are influenced by adiposity and bariatric surgery

Ciara McCarthy1, Philip Voyias1, Adaikala Antonysunil1, Kirsty McGee1, Alison Harte1, Ponnusamy Saravanan2, Ioannis Kyrou1, Sudhesh Kumar1, Philip McTernan1 & Gyanendra Tripathi1

1Division of Metabolic and Vascular Health, Warwick Medical School, University of Warwick, Coventry, United Kingdom; 2University of Warwick and George Eliot Hospital, Warwick Medical School, Coventry, CV2 2DX, United Kingdom.

Mitochondria are essential for synthesising ATP required for cellular metabolism. In response to changes in their cellular environment, mitochondria are able to alter their morphology and abundance through the balance of “fusion” and “fission” events. The aim of this study was to profile the expression of mitochondrial genes in the abdominal subcutaneous (AbSc) adipose tissue (AT) of lean, obese and Type 2 Diabetes Mellitus (T2DM) individuals and determine if bariatric surgery could modulate this gene expression.

Methods: AbSc AT from 12 Caucasian women, aged 38–60 yrs with T2DM and BMI >35 kg/m2, who underwent restrictive or malabsorptive bariatric surgery was collected at the time of surgery and 30 days post-surgery by biopsy. AbSc AT from two control groups of non-diabetic females was also included in the study; overweight/obese: n=11 with BMI>27.5 kg/m2, aged 35–60 and lean, n=6 with BMI<25.0 kg/m2 aged 40–50. Expression of genes was measured by qRT-PCR.

Results: Overweight/obese individuals had a higher expression profile of both fission (DRP1; 3 fold and Fis1 1.3 fold) and fusion genes (MFN2; 1.5 fold, OPA1; 7 fold and FOXC2; 2 fold) compared to lean (n=11, P<0.05). With the exception of DRP1 and FOXC2 (2 fold higher and lower respectively), pre-bariatric T2DM subjects had a gene expression profile similar to that of lean individuals. Following bariatric surgery, expression of both fusion (FOXC2, MFN2 and OPA1) and fission genes (DRP1 and FIS1) (n=12, P<0.05) significantly increased.

Conclusions: This study highlights differences in the expression profile of genes regulating mitochondrial fusion and fission in AT between lean, obese and T2DM individuals. Expression of both genes regulating fusion and fission processes were higher in AT of obese compared to lean subjects. Following bariatric surgery, the expression of these genes was up-regulated in the AT. Future studies examining the effects of 15% weight-loss are planned.

Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.