Post-gastric Bypass Patients Research Articles

Different Approaches in Management of Choledocholithiasis in Post-Gastric Bypass Patients

Introduction: Choledocholithiasis is commonly diagnosed in patients after gastric bypass surgeries. Management (Figure 1) can be challenging due to the altered gastrointestinal anatomy. We implemented three different approaches to remove CBD stones in post-gastric bypass patients. The aim of this study was to evaluate the safety and feasibility of these approaches and compare patient outcomes.

Постпрандіальний гіпоглікемічний синдром

Постпрандіальний гіпоглікемічний синдром, або реактивна гіпоглікемія, — вегетативні симптоми, такі як слабкість, втома, голод, нудота, серцебиття, занепокоєння, тремор, пітливість, що виникають через одну-дві години після прийому їжі. Синдром досить слабо висвітлений у літературі, більшість відомостей є розрізненими. Лабораторні критерії діагностики постпрандіальної реактивної гіпоглікемії досить контроверсивні, але більшість авторів схиляються до того, що це рівень глюкози крові нижче тощакової або ≤ 3,9 ммоль/л протягом двох годин після прийому їжі. Гіпоглікемія є результатом дисбалансу між надходженням глюкози в кров (від ендогенної продукції глюкози або екзогенної доставки) і використанням глюкози тканинами. Баланс між надходженням і витрачанням глюкози контролюється складною рівновагою глікорегулюючих гормонів. Інсулін, глюкагон і адреналін діють протягом кількох хвилин, а кортизол і гормон зросту — кілька годин. Це пояснює наявність негайних і відстрочених різноманітних ефектів: адренергічного, нейроглікопенічного, гастроінтестинального дискомфорту. Відомо, що в генезі постпрандіального синдрому лежать механізми, подібні до постгастректомічних у пацієнтів, оперованих з приводу морбідного ожиріння. Найбільш імовірним чинником формування реактивної гіпоглікемії є постпрандіальна гіперсекреція інсуліну під впливом глюкози і глюкагоноподібного пептиду (GLP-1), що є компонентом ентероендокринної системи, основна дія якого спрямована на цефалічну фазу формування насичення. Як у оперованих пацієнтів, так і у відносно здорових осіб симптоми виникають після прийому їжі, багатої простими вуглеводами. Симптоми досить ефективно лікуються прийомом їжі з вживанням вуглеводів із низьким глікемічним індексом і харчовими волокнами. При недостатності ефекту використовують препарати акарбози, інгібуючої α-глюкозидази тонкого кишечника, що є основним стимулом для секреції GLP-1. Таким чином, при епідемічній швидкості поширення ожиріння в умовах неадекватних харчових пріоритетів у дитячій популяції ймовірність значної поширеності постпрандіального синдрому досить вірогідна, що вимагає додаткового дослідження. При цьому зниження в раціоні простих вуглеводів може істотно поліпшити якість життя дітей із постпрандіальним дискомфортом.

Is Bypassing the Stomach a Means to Optimize Sodium Bicarbonate Supplementation? A Case Study With a Postbariatric Surgery Individual.

Sodium bicarbonate (SB) is an ergogenic supplement shown to improve high-intensity exercise via increased blood bicarbonate buffering. Substantial amounts of the ingested bicarbonate are neutralized in the stomach. Bariatric surgery results in a small gastric pouch which dramatically reduces exposure time of any ingested food in the stomach. The aim of this study was to examine the pharmacokinetics of orally ingested SB in a postgastric bypass individual to determine the magnitude of changes in blood bicarbonate and associated side effects. We hypothesized that SB supplementation in a gastric bypass model would result in greater blood bicarbonate increases and fewer side effects than in healthy individuals due to minimal bicarbonate losses in the stomach. One postbariatric male ingested 0.3g/kg·body mass of SB on three occasions (SB1, SB2, and SB3) and 0.3g/kg·body mass of placebo on a further occasion. Blood bicarbonate was determined before and every 10min following supplement ingestion for 3hr and then every 20min for a further 1hr. Side effects were reported using an adapted questionnaire at identical time points. Maximal increases in blood bicarbonate with SB were +20.0, +15.2, and +12.6mM, resulting in maximal bicarbonate concentrations of 42.8, 39.3, and 36.2mM. Area under the curve was SB1: 8,328mM/min; SB2: 7,747mM/min; SB3: 7,627mM/min, and 6,436mM/min for placebo. Side effects with SB were scarce. Maximal bicarbonate increases were well above those shown previously, with minimal side effects, indicative of minimal neutralization of bicarbonate in the stomach. The large increases in circulating bicarbonate and minimal side effects experienced by our postgastric surgery bypass patient are indicative that minimizing neutralization of bicarbonate in the stomach, as would occur with enteric coated capsules, may optimize SB supplementation and thus warrants investigation.

Outcomes of Endoscopic Retrograde Cholangiopancreatography (ERCP) and Sphincterotomy for Suspected Sphincter of Oddi Dysfunction (SOD) Post Roux-En-Y Gastric Bypass.

Sphincter of Oddi dysfunction (SOD) is thought to be a cause of chronic abdominal pain post Roux-en-Y gastric bypass, and current practice of performing endoscopic retrograde cholangiopancreatography (ERCP) with or without sphincterotomy is not supported by evidence. In addition to the complexity and risks of the procedure in patients with Roux-en-Y anatomy, the outcomes are uncertain and debatable. We performed a retrospective review and analysis of post-gastric bypass patients who had undergone ERCP with sphincterotomy to determine the effectiveness in patients with suspected SOD. Over a period of 5years at the University of Minnesota, we retrospectively reviewed a prospectively collected database of a cohort of patients whom had a previous Roux-en-Y gastric bypass and whom had a subsequent ERCP for suspected SOD. Patients were categorized by modified Milwaukee classification, and outcomes were evaluated by patients' self-reporting of symptoms at follow-up. We identified 50 patients who underwent laparoscopic-assisted gastrostomy for endoscopic retrograde cholangiopancreatography post Roux-en-Y gastric bypass over the study period. Within this group, 35 patients (70%) were suspected to have SOD. Nine patients (25.7%) were classified as type I, 19 patients (54.3%) type II, and seven patients (20%) type III. Thirty-four patients (97.1%) had biliary sphincterotomy, and 17 patients (48.6%) had both biliary and pancreatic sphincterotomy. Fourteen (40%) had repeated ERCP. At median follow-up of 11.5months, type I SOD had two responders (25%), type II had nine responders (52.9%), and type III had one responder (14.3%). A subgroup analysis did not show significant differences in improvement of symptoms between patients whom had single versus repeated ERCP or biliary sphincterotomy alone versus both biliary and pancreatic sphincterotomy. Three patients (9%) had post-ERCP pancreatitis. SOD in patients post Roux-en-Y gastric bypass is complex due to multiple confounding factors. Rome III and Milwaukee classification systems assist us in the diagnosis and treatment of sphincter dysfunction until we have a better way to predict treatment response post sphincterotomy. Current treatment is based on the type of disorder and anatomy of biliary ducts. Types I and II sphincter dysfunction particularly associated with dilated biliary duct on imaging have the best response to endoscopic sphincterotomy and therefore should be considered taking into account the risks and benefit. Repeated sphincterotomy and concurrent pancreatic sphincterotomy is generally not useful.

Diagnostic tools for post-gastric bypass hypoglycaemia.

In spite of its evident success, several late complications can occur after gastric bypass surgery. One of these is post-gastric bypass hypoglycaemia. No evidence-based guidelines exist in the literature on how to confirm the presence of this syndrome. This study aims to describe and compare the tests aimed at making a diagnosis of post-gastric bypass hypoglycaemia and to provide a diagnostic approach based upon the available evidence. A search was conducted in PubMed, Cochrane and Embase. A few questionnaires have been developed to measure the severity of symptoms in post-gastric bypass hypoglycaemia but none has been validated. The gold standard for provocation of a hypoglycaemic event is the oral glucose tolerance test or the liquid mixed meal tolerance test. Both show a high prevalence of hypoglycaemia in post-gastric bypass patients with and without hypoglycaemic complaints as well as in healthy volunteers. No uniformly established cut-off values for glucose concentrations are defined in the literature for the diagnosis of post-gastric bypass hypoglycaemia. For establishing an accurate diagnosis of post-gastric bypass hypoglycaemia, a validated questionnaire, in connection with the diagnostic performance of provocation tests, is the most important thing missing. Given these shortcomings, we provide recommendations based upon the current literature.

Gastric pouch reduction using StomaphyX™ in post Roux-en-Y gastric bypass patients does not result in sustained weight loss: a retrospective analysis

Gastric bypass is the "gold standard" procedure of bariatric surgery. However, 20.4-34.9% of these patients may fail to achieve or maintain the weight loss on long-term follow-up and may require additional procedures. StomaphyX has been promoted for weight reduction in such patients. To study whether endoluminal reduction of gastric pouch and stoma using StomaphyX results in sustained weight loss in patients who regain weight after gastric bypass. Retrospective chart review was performed on 59 postgastric bypass patients who underwent revision of gastric pouch using StomaphyX from 2007 to 2008. Postprocedure weight at 1 week, 1 month, and 6 months follow-up as well as weight at the time of the review was recorded for each patient. Average weight loss and excess body weight loss (EBWL) were 2.6 ± 2.3 kg and 7.3 ± 7.1% (n = 42) at 1 week, 3.7 ± 2.9 kg and 11.6 ± 12.1% (n = 31) at 1 month, and 3.8 ± 4.5 kg and 11.5 ± 17.9% (n = 10) at 6 months respectively. At the time of review, the average follow-up was 41 months, average weight loss was 1.7 ± 9.7 kg, and EBWL was 4.3 ± 29.8% (n = 53). Endoscopy in 12 patients at average 18 months follow-up showed no sustained reduction in pouch and stoma size. StomaphyX results in weight loss that is not sustained on long-term follow-up. Pouch and stoma tend to regain their preprocedure size on follow-up. StomaphyX cannot be recommended as a weight loss strategy in postgastric bypass patients who regain weight.

Treatment Option in Patient Presenting With Small Bowel Obstruction From Phytobezoar at the Jejunojejunal Anastomosis After Roux-en-Y Gastric Bypass

Bezoar is a rare cause of small bowel obstruction after Roux-en-Y gastric bypass (RYGB). We report the case of a 34-year-old man who developed small bowel obstruction secondary to a phytobezoar at the jejunojejunal anastomosis, 5½ years after the patient underwent RYGB for morbid obesity. The phytobezoar developed in the background of recurring abdominal pain. Imaging studies suggested complete obstruction of the alimentary limb. Laparoscopic exploration demonstrated complete obstruction of the alimentary and biliopancreatic limb. Patient had successful treatment with laparoscopic enterototomy. Six months after the laparoscopic removal of phytobezoar, patient remained asymptomatic. Phytobezoar formation must be considered in the differential diagnosis when postgastric bypass patients present late with obstructive symptoms. We believe that this is the first report of a phytobezoar obstructing at the jejunojejunal anastomosis after RYGB.

Effect of gastric bypass surgery on azithromycin oral bioavailability

Azithromycin is used widely for community-acquired infections. The timely administration of azithromycin in adequate doses minimizes treatment failure. Gastric bypass, a procedure that circumvents the upper gut, may compromise azithromycin plasma levels. We hypothesized that azithromycin concentrations would be reduced following gastric bypass. A single-dose pharmacokinetic study in 14 female post-gastric bypass patients and 14 sex- and body mass index (BMI)-matched controls (mean age 44 years and BMI 36.4 kg/m(2)) was performed. Subjects were administered two 250 mg azithromycin tablets at time 0 and plasma azithromycin levels were sampled at 0.5, 1, 1.5, 2, 3, 5, 7 and 24 h. The AUC of the plasma azithromycin concentrations from time 0 to 24 h (AUC(0-24)) was the primary outcome. Azithromycin concentrations were lower in gastric bypass patients compared with controls throughout the entire duration of sampling. Compared with controls, the AUC(0-24) was reduced in gastric bypass subjects by 32% [1.41 (SD 0.51) versus 2.07 (0.75) mg · h/L; P = 0.008], and dose-normalized AUC(0-24) was reduced by 33% [0.27 (0.12) versus 0.40 (0.13) kg · h/L; P = 0.009]. Peak azithromycin concentrations were 0.260 (0.115) in bypass subjects versus 0.363 (0.200) mg/L in controls (P = 0.08), and were reached at 2.14 (0.99) h in gastric bypass subjects and 2.36 (1.17) h in controls (P = 0.75). Azithromycin AUC was reduced by one-third in gastric bypass subjects compared with controls. The potential for early treatment failure exists, and dose modification and/or closer clinical monitoring of gastric bypass patients receiving azithromycin should be considered.

Endoscopic neogastrogastrostomy in a postgastric bypass patient by application of an endoscopic antegrade–retrograde rendezvous technique

The patient, a 45-year-old woman, initially underwent Roux-en-Y gastric bypass for morbid obesity. Three years later, it was complicated by a gastrojejunostomy ulcer with perforation requiring local repair. Additional complications with ischemic bowel and subsequent surgical revisions resulted in complete gastric outlet obstruction. A venting gastrostomy tube was placed in the gastric pouch, and a feeding gastrostomy tube was surgically placed in the gastric remnant. After some time, the patient strongly expressed her desire to eat orally. Because of the previous surgical complications and scar tissue, the surgical team requested an endoscopic attempt to reconnect the gastric pouch and excluded gastric remnant.

Glucagon-like peptide-1 (GLP-1) receptors are not overexpressed in pancreatic islets from patients with severe hyperinsulinaemic hypoglycaemia following gastric bypass

Glucagon-like peptide-1 (GLP-1) receptors are highly overexpressed in benign insulinomas, permitting in vivo tumour visualisation with GLP-1 receptor scanning. The present study sought to evaluate the GLP-1 receptor status in vitro in other pancreatic disorders leading to hyperinsulinaemic hypoglycaemia, specifically after gastric bypass surgery. Fresh frozen pancreatic tissue samples (n=7) from six gastric bypass surgery patients suffering from hyperinsulinaemic hypoglycaemia were evaluated for GLP-1 receptor content using in vitro receptor autoradiography, and compared with normal pancreas and with pancreatic insulinoma tissues. GLP-1 receptor analysis of the pancreatic tissues, which histopathologically were compatible with nesidioblastosis and originated from post-bypass hypoglycaemic patients, revealed a mean density value of GLP-1 receptors in the islets of 1,483 ± 183 dpm/mg tissue. Pharmacological characterisation indicated the presence of specific GLP-1 receptors. The density of islet GLP-1 receptor in post-gastric bypass patients did not differ from that of normal pancreas (1,563 ± 104 dpm/mg tissue, n = 10). Receptor density in pancreatic acini was low in post-bypass and control conditions. In contrast, benign insulinomas showed a high density of GLP-1 receptors, with a mean value of 8,302 ± 1,073 dpm/mg tissue (n = 6). In contrast to insulinoma, hyperinsulinaemic hypoglycaemia after gastric bypass surgery is not accompanied by overexpression of GLP-1 receptor in individual islets. Thus, patients with post-gastric bypass hyperinsulinaemic hypoglycaemia are not candidates for GLP-1 receptor imaging in vivo using radiolabelled exendin. These GLP-1 receptor data support the notion that the islet pathobiology of post-gastric bypass hypoglycaemia is distinctly different from that of benign insulinomas.

Nutritional Pyramid for Post-gastric Bypass Patients

Life-long nutrition education and diet evaluation are key to the long-term success of surgical treatment of obesity. Diet guidelines provided for bariatric surgery patients generally focus on a progression through dietary stages, from the immediate post-surgical period to 6 months after surgery. However, long-term dietary guidelines for those surgically treated for obesity are not readily available. Therefore, there is a need for dietary recommendations for meal planning and nutritional supplementation for bariatric surgery patients beyond the short-term, post-operative period. The purpose of this paper is to construct an educational tool to provide long-term nutritional and behavioral advice for the post-bariatric patient. The manuscript summarizes the current knowledge on dietary strategies and behaviors associated with beneficial nutritional outcomes in the long term of post-bariatric surgery patients. Dietary and nutritional recommendations are presented in the form of a "bariatric food pyramid" designed to be easily disseminated to patients. The development of educational tools that are easy to understand and follow is essential for effective patient management during the surgery follow-up period. The pyramid can be used as a tool to help both therapists and patients to understand nutrition recommendations and thus promote a healthy long-term post-op dietary pattern based on high-quality protein, balanced with nutrient-dense complex carbohydrates and healthy sources of essential fatty acids.

Pilot study evaluating technical feasibility and early outcomes of second-generation endosurgical platform for treatment of weight regain after gastric bypass surgery

Background For some gastric bypass patients, dilation of the gastrojejunal anastomosis (GJA) and/or gastric pouch is believed to contribute to weight regain. The present study had 2 objectives: (1) to assess the technical feasibility and safety of a novel endoscopic procedure called “revision obesity surgery endoscopic” (ROSE) using a second-generation, prototype endoscopic operating system that creates tissue plications to reduce the diameter of the GJA and the size of the gastric pouch; and (2) to assess the early outcomes regarding weight loss at a university hospital in the United States. Methods This was a prospective study of 5 patients who had regained a mean of 14.7 kg after gastric bypass with a dilated pouch and GJA on screening endoscopy. The gastric pouch and the GJA were measured before and after the procedure. The patients were followed up for a minimum of 3 months after the procedure. Weight changes were recorded. Results Technical success was achieved in all 5 patients (100%). The mean weight loss in the successful cases was 7.8 kg at 3 months. No major complications developed. Conclusion The results of our study have shown that the ROSE procedure using this second-generation prototype endoscopic operating system is technically feasible and appears safe. Our preliminary results suggest that the ROSE procedure is effective in reducing the size of both the GJA and the gastric pouch and could therefore be an alternative therapy for weight regain in postgastric bypass patients.

Hypocupremia

Purpose: With the mounting number of gastric bypass surgeries for the treatment of morbid obesity, complications of nutritional deficiencies must be recognized. A rare nutritional deficiency after gastrojejunal bypass is hypocupremia, which is clinically indistinguishable from the neurologic deficits of vitamin B12 deficiency. In addition, hypocupremia has been implicated in hematologic abnormalities of anemia and neutropenia. We describe a case with the rare combination of neurologic and hematologic abnormalities secondary to gastric bypass-associated hypocupremia. Methods: Case Report Results: A 45 year old white female underwent a Roux-en-Y gastric bypass for morbid obesity six years prior to presentation and complained of 15 months of progressive symptoms of lower extremity paresthesias, dysesthesias, and weakness. She had no other significant past medical or surgical history. On neurologic examination, the patient demonstrated a wide-based gait and a decreased tandem walk. Examination of her lower extremities demonstrated a bilateral absence of vibratory perception, decreased pin-prick to her ankles, strength of +1 and spastic quadriceps muscle stretch reflexes. A serum copper of 24 ug/dL (normal 80–155) and ceruloplasmin of 9 mg/dL (normal 22–58) were demonstrated. Concurrent with her neurologic deficits, the patient had episodes of anemia and neutropenia, which, at their nadirs, were 9.2 g/dL (normal 12–15) and 4.1 K/cumm (normal 4.5–11), respectively. Homocysteine, vitamin B12, ferritin and methylmalonic acid levels were normal. Upper endoscopy identified no abnormalities and biopsies of the small intestine were negative for celiac sprue. A thoracic spine MRI demonstrated a minimally increased focus of T2 signal intensity in the central spinal canal from T4 through T7. The patient was treated with an oral preparation of elemental copper at 2 mg/day, which halted the progression of the patient's neurologic symptoms and resulted in the complete resolution of her anemia and neutropenia within 2 months. She remains stable after 9 months follow-up. Conclusion: Copper is absorbed in the stomach and proximal small intestine; as a result, gastrojejunal bypass predisposes patients to copper deficiency. Since the recognition of hypocupremia after gastric bypass as a cause of myeloneuropathy, 15 cases have been reported in the literature with a further smaller proportion of patients demonstrating concomitant hematologic disturbances. The aim of this report is to raise the index of suspicion for hypocupremia in post-gastric bypass patients, who present with either neurologic or hematologic abnormalities related to copper deficiency.

Wernicke encephalopathy after bariatric surgery: Losing more than just weight

Bariatric surgery is a frequent treatment for obesity. Neurologic complications after surgery include encephalopathy, behavioral abnormalities, seizures, cranial nerve palsies, ataxia, plexopathy, myelopathy, polyneuropathy, mononeuropathy (carpal tunnel syndrome, meralgia paresthetica), compartment syndrome, neuropathy, and myopathy. In particular, Wernicke encephalopathy, caused by vitamin B1 deficiency, can result in permanent neurologic deficit.1,2 We report unusual clinical and imaging findings in a postgastric bypass patient with Wernicke encephalopathy. A 35-year-old woman underwent gastric bypass surgery for obesity. Subsequently, she reported anorexia, nausea, vomiting, and generalized fatigue, resulting in hospitalization. The patient continued to develop progressive hearing loss, psychomotor slowing, apathy, forgetfulness, ataxia, and bilateral hand paresthesias. In the 12th postoperative week, she had lost 40 lbs, was lethargic and confused, and had difficulty walking. She was awake but not attentive, speech was fluent, and comprehension was decreased. Pupils were equal and reactive to light, extraocular movements were intact, there was no nystagmus, and hearing …

Subclinical B12 Deficiency in Post-Roux-en-Y Gastric Bypass Patients: Prevalence, Implications and Prevention

To recognize and treat subclinical B12 deficiency in post-gastric bypass patients.

Medial thigh lift using periosteal pelvic anchoring in 50 consecutive postgastric bypass patients

Purpose: Due to the dramatic increase in bariatric surgeries being performed, there has also been an increase in elective medial thighs lifts after weight loss. One of the major disadvantages of the traditional medial thigh lift has been the resulting large, visible scar that usually migrates inferio-medially and becomes exposed in the visible areas of the medial thigh. Methods: Fifty postbariatric surgery patients requesting medial thigh reconstruction were selected. All patients refused a longitudinal medial thigh incision. These consecutive 50 patients underwent bilateral medial thigh lift through an incision placed from the medial infragluteal fold to the femoral triangle. A crescent area of skin and fat was removed. Then, the superficial fascial system was anchored with permanent suture to the periosteum of the medial pelvis. The incision was closed in multiple layers without drains. These consecutive patients were followed over 5 years. Results: All patients had significant improvement in medial thigh hygiene, contour, and appearance. All patients were pleased that they had undergone bilateral medial thigh lift. There were two wound dehiscences which healed with conservative wound management. To date, there have been no inferiomedial scar migrations. Most incisions are well hidden with undergarments. Conclusions: Periosteal pelvic anchoring provides a solid and permanent platform to support the medial thigh lift. Patients are satisfied with the placement of the incision and improved appearance of medial thighs. The medial thigh lift with crescent skin and fat excision with periosteal pelvic anchoring allows for satisfactory cosmetic results with minimal risk of scar migration. PII: S1550-7289(05)00263-7

A comparison of different methods of assessing the features of eating disorders in post‐gastric bypass patients: a pilot study

AbstractObjectiveTwo methods for assessing the features of eating disorders in post‐gastric bypass surgery patients were compared.MethodA total of 45 participants were administered the Eating Disorder Examination (EDE) Interview and completed the EDE‐Questionnaire (EDE‐Q4).ResultsThe EDE and the EDE‐Q4 were significantly correlated on the restraint, eating concern, weight concern and shape concern subscales. However, the mean difference in scores was significant for the restraint and eating concern subscales. The discrepancy between methods was largest for the restraint subscale. There was no agreement with regard to objective bulimic episodes and the agreement on subjective bulimic episodes was poor (kappa 0.276). However, the frequencies of subjective bulimic episodes were significantly correlated and did not differ significantly.DiscussionThe EDE‐Q4 seems suitable in assessing eating‐ related psychopathology (subscales) in post‐surgery patients. However, the questionnaire appears to have limited utility for assessing binge eating in this population. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.

Impaired plasma fatty acid oxidation in extremely obese women.

Skeletal muscle from extremely obese individuals exhibits decreased lipid oxidation compared with muscle from lean controls. It is unknown whether this effect is observed in vivo or whether the phenotype is preserved after massive weight loss. The objective of this study was to compare free fatty acid (FFA) oxidation during rest and exercise in female subjects who were either lean [n = 7; body mass index (BMI) = 22.6 +/- 2.2 kg/m(2)] or extremely obese (n = 10; BMI = 40.8 +/- 5.4 kg/m(2)) or postgastric bypass patients who had lost >45 kg (weight reduced) (n = 6; BMI = 33.7 +/- 9.9 kg/m(2)) with the use of tracer ([(13)C]palmitate and [(14)C]acetate) methodology and indirect calorimetry. The lean group oxidized significantly more plasma FFA, as measured by percent fatty acid uptake oxidized, than the extremely obese or weight-reduced group during rest (66.6 +/- 14.9 vs. 41.5 +/- 16.4 vs. 39.9 +/- 15.3%) and exercise (86.3 +/- 11.9 vs. 56.3 +/- 22.1 vs. 57.3 +/- 20.3%, respectively). BMI significantly correlated with percent uptake oxidized during both rest (r = -0.455) and exercise (r = -0.459). In conclusion, extremely obese women and weight-reduced women both possess inherent defects in plasma FFA oxidation, which may play a role in massive weight gain and associated comorbidities.

Increased binding of insulin to mononuclear blood cells following gastric bypass for morbid obesity

The insulin resistance of obesity may be related to “down-regulation” of insulin receptor number and/or affinity in vivo which is reflected quantitatively by decreased insulin binding to blood mononuclear cells in vitro. To determine the effect of surgically induced weight loss on insulin receptor function, blood mononuclear cell insulin binding was measured in normal, morbidly obese (mean 270.0 ± 21.3% of ideal body weight), and post-gastric bypass patients (mean 45.3 ± 13.5 kg weight loss) who, 2 years postoperatively, were still 136 ± 27% of ideal weight. In vitro, at all physiologic concentrations of insulin the morbidly obese group bound significantly less insulin than either the postoperative patients or normal controls. There was a two- to three-fold reduction in receptor number, with no substantial alteration of insulin binding affinity. The data suggest that surgically induced weight loss can result in “up-regulation” of insulin receptor function, and that normalization of weight is not necessary for correction of insulin receptor function in morbidly obese patients.