The impact of bariatric surgery on bone, sex steroid status, inflammation and gut permeability

The epidemic of obesity is associated with an increasing demand of bariatric surgery. However, bariatric surgery can lead to various complications such as osteoporosis. Today, Sleeve Gastrectomy (SG) has become the most performed bariatric surgery worldwide, because it is believed to lead to less complications than the Roux-en-Y Gastric Bypass (RYGB) procedure. After SG, bone loss has been observed, however the mechanism behind the bone loss remains unclear. We have previously shown that malabsorption and parathyroid hormone (PTH) are not responsible for bone loss after SG and RYGB in mice. Besides PTH, sex steroid deficiency is the most important driver of bone loss in men and women, leading to osteoporosis. Additionally, research shows that microbiota are necessary for sex steroid deficiency to induce bone loss. Therefore, we are going to investigate the effects of SG on sex steroid status, inflammation and microbiome. Mice will be used to first characterize the sex steroid status and inflammation after SG, after which also the permeability and microbiome will be investigated. From this we will be able to develop a strategy to prevent bone loss after surgery and elucidate the weight of the separate mechanisms contributing to bone loss.