Nilanjana Tewari

Obesity-related insulin resistance: implications for the surgical patient

In healthy surgical patients, preoperative fasting and major surgery induce development of insulin resistance (IR). IR can be present in up to 41% of obese patients without diabetes and this can rise in the postoperative period, leading to an increased risk of postoperative complications. Inflammation is implicated in the aetiology of IR. This review examines obesity-associated IR and its implications for the surgical patient. Searches of the Medline and Science Citation Index databases were performed using various key words in combinations with the Boolean operators AND, OR and NOT. Key journals, nutrition and metabolism textbooks and the reference lists of key articles were also hand searched. Adipose tissue has been identified as an active endocrine organ and the chemokines secreted as a result of macrophage infiltration have a role in the pathogenesis of IR. Visceral adipose tissue appears to be the most metabolically active, although results across studies are not consistent. Results from animal and human studies often provide conflicting results, which has rendered the pursuit of a common mechanistic pathway challenging. Obesity-associated IR appears, in part, to be related to inflammatory changes associated with increased adiposity. Postoperatively, the surgical patient is in a proinflammatory state, so this finding has important implications for the obese surgical patient.

Mixed Periampullary Adenocarcinoma and Somatostatinoma with Small Bowel Gastrointestinal Stromal Tumour in Neurofibromatosis Type 1

CONTEXT Gastrointestinal (GI) involvement is present in about one quarter of cases of neurofibromatosis type 1 (NF1). Adenocarcinomas have been reported in several organs. Gastrointestinal stromal tumors are the most common GI lesion seen in NFI. GISTs in combination with ampullary neuroendocrine tumors in NF-1 have been reported rarely. CASE REPORT We present the case of a 44-year-old man who presented with a history of obstructive jaundice and weight loss. Investigations revealed a pancreatic tumor associated with a common bile duct (CBD) stricture. At operation, an ampullary adenocarcinoma that infiltrated into the head of pancreas with an adjacent somatostatinoma was found. In addition, a small bowel GIST was present. CONCLUSIONS Mixed periampullary adenocarcinoma and somatostatinoma in a patient with NF1 has only been previously reported once. The current case highlights the spectrum of associated tumor types which can be seen in association with NF1. Patients with NF1 who present with jaundice and weight loss should be investigated in the usual manner with increased suspicion for duodenal and ampullary tumors.

Regulation of food intake after surgery and the gut brain axis.

Purpose of reviewTo highlight recent developments relating control of food intake after surgery and the gut–brain axis by reviewing clinically relevant English language articles mainly from January 2011 to March 2013. Recent findingsThe gut–brain axis involves a number of complex interactions between hypothalamic nuclei and the gastrointestinal tract. In the postoperative period, release of cytokines and neuromodulators are involved in the control of food intake. Analogues of neuromodulators have been developed and tested in animal studies. The emerging field of metabolic surgery has allowed study of these mechanisms in greater detail. SummaryThe current epidemic of worldwide obesity demands further research into the mechanisms underlying control of food intake.

Three Cases of Concomitant Intraductal Papillary Mucinous Neoplasm and Pancreatic Neuroendocrine Tumour

CONTEXT Intraductal papillary mucinous neoplasms (IPMNs) are uncommon tumours which can be associated with pancreatic and extrapancreatic malignancies. The association of IPMN and neuroendocrine tumours of the pancreas has been reported previously but is exceedingly rare. CASE REPORT We report three cases of IPMN treated with total pancreatectomy/extended distal pancreatectomy. Histopathological analysis of the resected specimens revealed concomitant IPMN and neuroendocrine tumour. Two patients had adenocarcinoma as well. CONCLUSIONS The presence of an IPMN may place the entire pancreas at risk of developing other tumour types and vigilance during all stages of management is necessary to ensure optimal treatment.

Lymphoepithelial Cyst of the Pancreas and Elevated Cyst Fluid Carcinoembryonic Antigen: A Diagnostic Challenge

CONTEXT Pancreatic lymphoepithelial cysts are rare, benign cysts which can present diagnostic difficulties. Non-invasive imaging alone is unreliable in distinguishing between benign and malignant cysts. Endoscopic ultrasound (EUS) and fine needle aspiration (FNA) with analysis of cyst fluid is more reliable, but invasive. In addition, tumor markers such as carcinoembryonic antigen (CEA) can be grossly elevated in cyst fluid of benign cysts. CASE REPORT We present the case of a 67 year old man with an incidental finding of a pancreatic cyst. EUS and FNA-guided aspiration of cyst fluid was performed. Fluid CEA was grossly elevated and resectional surgery was performed. On histological examination the diagnosis was confirmed as lymphoepithelial cyst of the pancreas. CONCLUSION Tumor markers such as CEA can be elevated in the cyst fluid of benign pancreatic conditions such as lymphoepithelial cyst. Although the diagnosis is challenging preoperatively, if a systematic algorithm is followed, these conditions can be managed safely and efficiently.

Postoperative inflammation and insulin resistance in relation to body composition, adiposity and carbohydrate treatment: a randomised controlled study

Summary Background & aims The aims of this study were to identify whether differences in distribution of adipose tissue and skeletal muscle in obese and non-obese individuals contribute to the magnitude of the postoperative inflammatory response and insulin resistance, with and without preoperative treatment with carbohydrate drinks. Methods Thirty-two adults (16 obese/16 non-obese) undergoing elective major open abdominal surgery participated in this 2 × 2 factorial, randomised, double-blind, placebo-controlled study. Participants received Nutricia preOp® or placebo (800 ml on the night before surgery/400 ml 2–3 h preoperatively) after stratifying for obesity. Insulin sensitivity was measured using the hyperinsulinaemic-euglycaemic clamp preoperatively and on the 1st postoperative day. Vastus lateralis, omental and subcutaneous fat biopsies were taken pre- and postoperatively and analysed after RNA extraction. The primary endpoint was within subject differences in insulin sensitivity. Results Major abdominal surgery was associated with a 42% reduction in insulin sensitivity from mean(SD) M value of 37.3(11.8) μmol kg−1 fat free mass (FFM) to 21.7(7.4) μmol kg−1 FFM, but this was not influenced by obesity or preoperative carbohydrate treatment. Activation of the triggering receptor expressed on myeloid cells (TREM1) pathway was seen in response to surgery in omental fat samples. In postoperative muscle samples, gene expression differences indicated activation of the peroxisome proliferator-activated receptor (PPAR-α)/retinoid X-receptor (RXR-α) pathway in obese but not in non-obese participants. There were no significant changes in gene expression pathways associated with carbohydrate treatment. Conclusion The reduction in insulin sensitivity associated with major abdominal surgery was confirmed but there were no differences associated with preoperative carbohydrates or obesity.