PYY plays a key role in the resolution of diabetes following bariatric surgery in humans.

BACKGROUND: Bariatric surgery leads to early and long-lasting remission of type 2 diabetes (T2D). However, the mechanisms behind this phenomenon remain unclear. Among several factors, gut hormones are thought to be crucial mediators of this effect. Unlike GLP-1, the role of the hormone peptide tyrosine tyrosine (PYY) in bariatric surgery in humans has been limited to appetite regulation and its impact on pancreatic islet secretory function and glucose metabolism remains under-studied. METHODS: Changes in PYY concentrations were examined in obese patients after bariatric surgery and compared to healthy controls. Human pancreatic islet function was tested upon treatment with sera from patients before and after the surgery, in presence or absence of PYY. Alterations in intra-islet PYY release and insulin secretion were analysed after stimulation with short chain fatty acids (SCFAs), bile acids and the cytokine IL-22. FINDINGS: We demonstrate that PYY is a key effector of the early recovery of impaired glucose-mediated insulin and glucagon secretion in bariatric surgery. We establish that the short chain fatty acid propionate and bile acids, which are elevated after surgery, can trigger PYY release not only from enteroendocrine cells but also from human pancreatic islets. In addition, we identify IL-22 as a new factor which is modulated by bariatric surgery in humans and which directly regulates PYY expression and release. INTERPRETATION: This study shows that some major metabolic benefits of bariatric surgery can be emulated ex vivo. Our findings are expected to have a direct impact on the development of new non-surgical therapy for T2D correction.

Bariatric surgery: nutritional considerations for patients.

Nutritional deficiencies are common in patients who are obese and therefore individuals considering bariatric surgery may require dietary supplementation with multivitamins and minerals before surgery. Nutritional deficiencies following bariatric surgery are often proportional to the degree of malabsorption created by the surgical procedure or the extent of weight loss. Eating habits often contribute to nutritional deficiencies, so appropriate dietary and lifestyle counselling are essential following bariatric procedures to ensure appropriate macronutrient and micronutrient status. Nutritional supplementation following bariatric surgery commonly includes calcium with vitamin D, iron and vitamin B12 in addition to a daily multivitamin and mineral tablet. Although general guidelines exist, individual monitoring and tailoring are frequently required. This article provides an update of guidelines regarding the most common nutritional concerns and myths surrounding bariatric surgery.

An unusual cause of dysuria.

Laparoscopic adjustable gastric band (LAGB) insertion has become an increasingly common treatment for severe obesity worldwide. As a consequence, LAGB complications are reported in increasing numbers and usually present to acute surgical units. This report describes the development of lower abdominal pain and dysuria in a patient who had undergone LAGB surgery 20 months previously. Repeated symptomatic treatment for a possible urinary tract infection in the community setting had been unsuccessful. The cause was found to be a fracture in the tubing connecting the LAGB device with its subcutaneous adjusting port, which was causing persistent bladder irritation. It is recommended that when LAGB patients present with acute lower abdominal pain, consideration should be made as to whether a tubing disconnection has occurred. Such a complication may be visualised by abdominal radiography. Advice can be sought on this and other complications of bariatric surgery by contacting the regional bariatric surgical centre where definitive management would be undertaken.