February 2014

Metabolic Surgery for End-Organ Health?

Sat, 8 February 14 09:00

With around one in three adults worldwide classified as being either overweight or obese, effective intervention is urgently required to arrest this global epidemic. While bariatric surgery is the most effective treatment for obesity as measured by weight loss and improved control of glycaemia, its use is largely confined to patients with severe obesity and with significant comorbidity.

The effectiveness of bariatric surgery was the subject of a recent series published in The Lancet Diabetes & Endocrinology (February 2014) with contributions by Professor Carel Le Roux, UCD Professor of Experimental Pathology and UCD Conway Investigator at the UCD Diabetes Complications Research Centre.

The study by Prof Le Roux and Dr Alexander D Miras (Molecular and Metabolic Imaging Group, Imperial College London) examined the available evidence for the effect of bariatric surgery on type 2 diabetes or endocrine-related end-organ damage.  They conclude that based on present data, in most cases patients’ pancreatic, renal, retinal, peripheral nerve, cardiovascular, hepatic, and reproductive function or disease are expected to either stabilise or improve postoperatively.

The precise molecular mechanisms underpinning disease stabilisation are not fully understood, but include beneficial effects of surgery on systemic and tissue-specific inflammation, glycaemic control, blood pressure, and lipid profiles.  There is also evidence to indicate surgery-specific effects arising from increased post-operative production of gut hormones.

Miras and Le Roux note that many of these clinical outcomes have not been thoroughly examined as there have been no randomised controlled trials which compare bariatric surgery with non-surgical interventions.  They argue that such trials are urgently needed to provide the necessary evidence on whether the risks of surgery outweigh the benefits in end-organ health.

This research is also necessary to investigate why in some cases, after bariatric surgery there is an exacerbation of end-organ damage.  Predictive markers are required to ensure surgery is not offered to such patients and to delineate where pharmacotherapy would be more effective.

This study forms part of a four part Lancet series questioning why despite improvements in surgical techniques, bariatric surgery is used only as a treatment of last resort and even then, its use is tightly controlled by national clinical guidelines.  In addition to examining the reversal of end-organ damage following bariatric surgery, the series also explores changes in glucose metabolism, bone loss and mineral metabolism following the surgery.  The series also assesses the suitability of current clinical criteria guiding the use of metabolic surgery.

Prof Le Roux is a Science Foundation Ireland-funded researcher within the UCD Diabetes Complications Research Centre at the UCD Conway Institute and is Professor of Experimental Pathology.