Laparoscopic Vertical Sleeve Gastrectomy as a Treatment Option for Adults with Diabetes Mellitus

Obesity is a major factor in the worldwide rise in the prevalence of type 2 diabetes mellitus. The obesity "epidemic" will require novel, effective interventions to permit both the prevention and treatment of diabetes caused by obesity. Laparoscopic vertical sleeve gastrectomy is a newer bariatric surgical procedure with a lower risk of complications (compared to Roux-en-Y gastric bypass surgery). Based in part on restriction of daily caloric intake, sleeve gastrectomy has a major role in inducing significant weight loss and weight loss is maintained for at least 10 years. Prior studies have supported the utility of the vertical sleeve gastrectomy for the treatment and management of subgroups of individuals with diabetes mellitus. There are reports of 11% to 76.9% of obese individuals discontinuing use of diabetic medications in studies lasting up to 8 years after vertical sleeve gastrectomy. Major ongoing issues include the preoperative determination of the suitability of diabetic patients to undergo this bariatric surgical procedure. Understanding how this surgical procedure is performed and the resulting anatomy is important when vertical sleeve gastrectomy is being considered as a treatment option for diabetes. In the postoperative periods, specific macronutrient goals and micronutrient supplements are important for successful and safer clinical results. An understanding of immediate- and long term- potential complications is important for reducing the potential risks of vertical sleeve gastrectomy. This includes the recognition and treatment of postoperative nutritional deficiencies and disorders. Vertical sleeve gastrectomy is a component of a long term, organized program directed at treating diabetes related to obesity. This approach may result in improved patient outcomes when vertical sleeve gastrectomy is performed to treat type 2 diabetes in obese individuals.

Bowel symptoms are associated with hypovitaminosis D in individuals with medically complicated obesity

We reported that 30% of individuals with medically complicated obesity have bowel symptoms, suggesting irritable bowel syndrome, but this prevalence of bowel symptoms is not related to body mass index or diabetes mellitus. Hypovitaminosis D is common in individuals with obesity and type 2 diabetes mellitus and is associated with depressive symptoms. Because antidepressants improve global symptoms in individuals with bowel symptoms, we hypothesize that the high prevalence of bowel symptoms in medically complicated obesity is associated with hypovitaminosis D. This is a single-institution, retrospective cohort study performed in a large, urban community teaching hospital. Over 2 years, individuals considering bariatric surgery completed a Manning symptom questionnaire to quantify bowel symptoms. Serum 25-hydroxy vitamin D was ordered, and the results were recorded for all individuals. Among 271 subjects, 229 subjects (80% women, 20% men; 67% black, 31% white; age range: 23-73 years; body mass index range: 35-91 kg/m²) completed 25-hydroxy vitamin D testing. Sixty-seven subjects (29%) have 3 to 6 Manning bowel symptoms, suggesting irritable bowel syndrome; 84 (37%) have type 2 diabetes; and 180 (79%) had vitamin D insufficiency. There are significant negative associations between Manning bowel symptoms and vitamin D concentrations in subjects with obesity (P = .01) and with type 2 diabetes mellitus and obesity (P = .007). The results support our hypothesis that the high prevalence of bowel symptoms in people with medically complicated obesity is associated with hypovitaminosis D. A prospective study is required to evaluate vitamin D supplementation and relief of bowel symptoms in people with medically complicated obesity.

Current and future impact of clinical gastrointestinal research on patient care in diabetes mellitus

The worldwide rise in the prevalence of obesity supports the need for an increased interaction between ongoing clinical research in the allied fields of gastrointestinal medicine/surgery and diabetes mellitus. There have been a number of clinically-relevant advances in diabetes, obesity, and metabolic syndrome emanating from gastroenterological research. Gastric emptying is a significant factor in the development of upper gastrointestinal symptoms. However, it is not the only mechanism whereby such symptoms occur in patients with diabetes. Disorders of intrinsic pacing are involved in the control of stomach motility in patients with gastroparesis; on the other hand, there is limited impact of glycemic control on gastric emptying in patients with established diabetic gastroparesis. Upper gastrointestinal functions related to emptying and satiations are significantly associated with weight gain in obesity. Medications used in the treatment of diabetes or metabolic syndrome, particularly those related to pancreatic hormones and incretins affect upper gastrointestinal tract function and reduce hyperglycemia and facilitate weight loss. The degree of gastric emptying delay is significantly correlated with the weight loss in response to liraglutide, a glucagon-like peptide-1 analog. Network meta-analysis shows that liraglutide is one of the two most efficacious medical treatments of obesity, the other being the combination treatment phentermine-topiramate. Interventional therapies for the joint management of obesity and diabetes mellitus include newer endoscopic procedures, which require long-term follow-up and bariatric surgical procedure for which long-term follow up shows advantages for individuals with diabetes. Newer bariatric procedures are presently undergoing clinical evaluation. On the horizon, combination therapies, in part directed at gastrointestinal functions, appear promising for these indications. Ongoing and future gastroenterological research when translated to care of individuals with diabetes mellitus should provide additional options to improve their clinical outcomes.

Organization of future training in bariatric gastroenterology

A world-wide rise in the prevalence of obesity continues. This rise increases the occurrence of, risks of, and costs of treating obesity-related medical conditions. Diet and activity programs are largely inadequate for the long-term treatment of medically-complicated obesity. Physicians who deliver gastrointestinal care after completing traditional training programs, including gastroenterologists and general surgeons, are not uniformly trained in or familiar with available bariatric care. It is certain that gastrointestinal physicians will incorporate new endoscopic methods into their practice for the treatment of individuals with medically-complicated obesity, although the long-term impact of these endoscopic techniques remains under investigation. It is presently unclear whether gastrointestinal physicians will be able to provide or coordinate important allied services in bariatric surgery, endocrinology, nutrition, psychological evaluation and support, and social work. Obtaining longitudinal results examining the effectiveness of this ad hoc approach will likely be difficult, based on prior experience with other endoscopic measures, such as the adenoma detection rates from screening colonoscopy. As a long-term approach, development of a specific curriculum incorporating one year of subspecialty training in bariatrics to the present training of gastrointestinal fellows needs to be reconsidered. This approach should be facilitated by gastrointestinal trainees’ prior residency training in subspecialties that provide care for individuals with medical complications of obesity, including endocrinology, cardiology, nephrology, and neurology. Such training could incorporate additional rotations with collaborating providers in bariatric surgery, nutrition, and psychiatry. Since such training would be provided in accredited programs, longitudinal studies could be developed to examine the potential impact on accepted measures of care, such as complication rates, outcomes, and costs, in individuals with medically-complicated obesity.

Dysphagia after vertical sleeve gastrectomy: Evaluation of risk factors and assessment of endoscopic intervention

AIM

To evaluate the risks of medical conditions, evaluate gastric sleeve narrowing, and assess hydrostatic balloon dilatation to treat dysphagia after vertical sleeve gastrectomy (VSG).

METHODS

VSG is being performed more frequently worldwide as a treatment for medically-complicated obesity, and dysphagia is common post-operatively. We hypothesize that post-operative dysphagia is related to underlying medical conditions or narrowing of the gastric sleeve. This is a retrospective, single institution study of consecutive patients who underwent sleeve gastrectomy from 2013 to 2015. Patients with previous bariatric procedures were excluded. Narrowing of a gastric sleeve includes: inability to pass a 9.6 mm gastroscope due to stenosis or sharp angulation or spiral hindering its passage.

RESULTS

Of 400 consecutive patients, 352 are included; the prevalence of dysphagia is 22.7%; 33 patients (9.3%) have narrowing of the sleeve with 25 (7.1%) having sharp angulation or a spiral while 8 (2.3%) have a stenosis. All 33 patients underwent balloon dilatation of the gastric sleeve and dysphagia resolved in 13 patients (39%); 10 patients (30%) noted resolution of dysphagia after two additional dilatations. In a multivariate model, medical conditions associated with post-operative dysphagia include diabetes mellitus, symptoms of esophageal reflux, a low whole blood thiamine level, hypothyroidism, use of non-steroidal anti-inflammatory drugs, and use of opioids.

CONCLUSION

Narrowing of the gastric sleeve and gastric sleeve stenosis are common after VSG. Endoscopic balloon dilatations of the gastric sleeve resolves dysphagia in 69% of patients.

Development of minimally invasive techniques for management of medically-complicated obesity

The field of bariatric surgery has been rapidly growing and evolving over the past several decades. During the period that obesity has become a worldwide epidemic, new interventions have been developed to combat this complex disorder. The development of new laparoscopic and minimally invasive treatments for medically-complicated obesity has made it essential that gastrointestinal physicians obtain a thorough understanding of past developments and possible future directions in bariatrics. New laparoscopic advancements provide patients and practitioners with a variety of options that have an improved safety profile and better efficacy without open, invasive surgery. The mechanisms of weight loss after bariatric surgery are complex and may in part be related to altered release of regulatory peptide hormones from the gut. Endoscopic techniques designed to mimic the effects of bariatric surgery and endolumenal interventions performed entirely through the gastrointestinal tract offer potential advantages. Several of these new techniques have demonstrated promising, preliminary results. We outline herein historical and current trends in the development of bariatric surgery and its transition to safer and more minimally invasive procedures designed to induce weight loss.

Constipation in patients with thiamine deficiency after Roux-en-Y gastric bypass surgery

BACKGROUND/AIMS

Roux-en-Y gastric bypass surgery is the most common bariatric surgery worldwide. We have described thiamine deficiency in patients with small intestinal bacterial overgrowth after gastric bypass. We hypothesized that symptoms of thiamine deficiency are common after gastric bypass. The aims of this study were to examine the prevalence of and treatment of symptoms of thiamine deficiency after gastric bypass.

METHODS

This is a prospective study performed in a large urban, community hospital. Consecutive gastric bypass patients seen from February 1, 2008 to May 1, 2009 are included. Thiamine deficiency in this study included both: consistent clinical symptoms and either (1) low blood thiamine level or (2) resolution of clinical symptoms after receiving thiamine.

RESULTS

Of 151 patients, 25 females and 2 males met the criteria for thiamine deficiency (prevalence of 18%). In these 27 patients, 12 had one symptom of thiamine deficiency, while 15 had symptoms consistent with multiple subtypes. Eleven patients reported constipation at 0.33-12 years (mean 4.8) after gastric bypass. Elevated serum folate levels were seen in 6 of 10 tested patients and there was an abnormal glucose-hydrogen breath test in 9 of 10 tested patients, supporting the presence of small intestinal bacterial overgrowth. Frequency of defecation improved after thiamine treatment.

CONCLUSION

Thiamine deficiency resulting from small intestinal bacterial overgrowth should be considered in patients being seen for constipation after gastric bypass surgery.

Nutritional deficiencies after bariatric surgery

Lifestyle intervention programmes often produce insufficient weight loss and poor weight loss maintenance. As a result, an increasing number of patients with obesity and related comorbidities undergo bariatric surgery, which includes approaches such as the adjustable gastric band or the 'divided' Roux-en-Y gastric bypass (RYGB). This Review summarizes the current knowledge on nutrient deficiencies that can develop after bariatric surgery and highlights follow-up and treatment options for bariatric surgery patients who develop a micronutrient deficiency. The major macronutrient deficiency after bariatric surgery is protein malnutrition. Deficiencies in micronutrients, which include trace elements, essential minerals, and water-soluble and fat-soluble vitamins, are common before bariatric surgery and often persist postoperatively, despite universal recommendations on multivitamin and mineral supplements. Other disorders, including small intestinal bacterial overgrowth, can promote micronutrient deficiencies, especially in patients with diabetes mellitus. Recognition of the clinical presentations of micronutrient deficiencies is important, both to enable early intervention and to minimize long-term adverse effects. A major clinical concern is the relationship between vitamin D deficiency and the development of metabolic bone diseases, such as osteoporosis or osteomalacia; metabolic bone diseases may explain the increased risk of hip fracture in patients after RYGB. Further studies are required to determine the optimal levels of nutrient supplementation and whether postoperative laboratory monitoring effectively detects nutrient deficiencies. In the absence of such data, clinicians should inquire about and treat symptoms that suggest nutrient deficiencies.

Origins of and recognition of micronutrient deficiencies after gastric bypass surgery

Roux-en-Y gastric bypass surgery remains the major surgical option for individuals with medically complicated obesity. The importance of preoperative evaluation to permit identification of micronutrient deficiencies is being re-evaluated. The risk of complications related to pregnancy after gastric bypass supports careful follow-up. Micronutrient deficiencies are common in postoperative gastric bypass patients, despite the suggested use of routine vitamin and mineral supplements after surgery. Copper deficiency must be considered as an origin for visual disorders after gastric bypass. Vitamin D deficiency with metabolic bone disease remains common after gastric bypass and the results suggest that the present postoperative supplements of calcium and vitamin D are inadequate. Major nutritional complications of bariatric surgery are occurring more than 20 years after surgery. There is no evidence for intestinal adaptation as there remains decreased intestinal absorption of iron up to 18 months after gastric bypass surgery. This article supports ongoing examination of nutritional complications after gastric bypass surgery and supports the notion that the daily doses of micronutrient supplements, such as vitamin D, may need to be revised.

Managing medical and surgical disorders after divided Roux-en-Y gastric bypass surgery

The National Longitudinal Study of Adolescent Health and the National Health and Nutrition Examination Survey reported that over 40% of the US population is overweight. The average weight loss attained by medical management programs is neither sufficient nor durable enough to treat medically complicated obesity. An estimated 220,000 bariatric procedures are performed yearly in the USA and Canada. The divided Roux-en-Y gastric bypass (RYGB) is performed most commonly in these countries and is considered the gold standard bariatric surgical procedure. The complexity of RYGB means that serious and potentially preventable perioperative complications can occur. RYGB alters the normal anatomy and physiology of the upper gut, which has predictable adverse effects and potential complications. Patients seek advice and care for symptoms that develop or persist after RYGB; although some symptoms are expected and predictable, others are complications that may or may not require active medical or surgical intervention. Physicians should be able to predict and manage most postoperative medical and nutritional disorders related to RYGB and should be prepared to assess patients for potential referral for surgical intervention or revision.

Postoperative metabolic and nutritional complications of bariatric surgery

Bariatric surgery has become an increasingly important method for management of medically complicated obesity. In patients who have undergone bariatric surgery, up to 87% with type 2 diabetes mellitus develop improvement or resolution of their disease postoperatively. Bariatric surgery can reduce the number of absorbed calories through performance of either a restrictive or a malabsorptive procedure. Patients who have undergone bariatric surgery require indefinite, regular follow-up care by physicians who need to follow laboratory parameters of macronutrient as well as micronutrient malnutrition. Physicians who care for patients after bariatric surgery need to be familiar with common postoperative syndromes that result from specific nutrient deficiencies.

Enteric neurodegeneration in ageing

The objective of this article is to review the clinical presentation and neurobiology of degeneration of the enteric nervous system with emphasis on human data where available. Constipation, incontinence and evacuation disorders are frequently encountered in the ageing population. Healthy lower gastrointestinal function is essential for successful ageing as it is critical to maintaining independence and autonomy to pursue further activity. One clinical expression of enteric neurodegeneration is constipation. However, the aetiology may be multifactorial as disturbances of epithelial, muscle or neural function may all result from neurodegeneration. There is evidence of loss of excitatory (e.g. cholinergic) enteric neurons and interstitial cells of Cajal, whereas inhibitory (including nitrergic) neurons appear unaffected. Understanding neurodegeneration in the enteric nervous system is key to developing treatments to reverse it. Neurotrophins have been shown to accelerate colonic transit and relieve constipation in the medium term; they are also implicated in maintenance programmes in adult enteric neurons through a role in antioxidant defence. However, their effects in ageing colon require further study. There is evidence that 5-HT(2) and 5-HT(4) mechanisms are involved in development, maintenance and survival of enteric neurons. Further research is needed to understand and potentially reverse enteric neurodegeneration.

Enteric neurodegeneration in ageing

The objective of this article is to review the clinical presentation and neurobiology of degeneration of the enteric nervous system with emphasis on human data where available. Constipation, incontinence and evacuation disorders are frequently encountered in the ageing population. Healthy lower gastrointestinal function is essential for successful ageing as it is critical to maintaining independence and autonomy to pursue further activity. One clinical expression of enteric neurodegeneration is constipation. However, the aetiology may be multifactorial as disturbances of epithelial, muscle or neural function may all result from neurodegeneration. There is evidence of loss of excitatory (e.g. cholinergic) enteric neurons and interstitial cells of Cajal, whereas inhibitory (including nitrergic) neurons appear unaffected. Understanding neurodegeneration in the enteric nervous system is key to developing treatments to reverse it. Neurotrophins have been shown to accelerate colonic transit and relieve constipation in the medium term; they are also implicated in maintenance programmes in adult enteric neurons through a role in antioxidant defence. However, their effects in ageing colon require further study. There is evidence that 5-HT(2) and 5-HT(4) mechanisms are involved in development, maintenance and survival of enteric neurons. Further research is needed to understand and potentially reverse enteric neurodegeneration.

Chronic gastrointestinal symptoms of Thomas "Stonewall" Jackson following Mexican-American War exposure: a medical hypothesis

In a recent study, a large proportion of veterans seen for chronic heartburn or dyspepsia after the Persian Gulf War had evidence for Helicobacter pylori. Thomas Jackson was born and raised in an area of West Virginia that has a high prevalence of H. pylori. He suffered chronic dyspeptic symptoms following his service in the Mexican-American War. Therapies that he tried included treatment with a variant of the Sippy diet. Following a bullet wound to the left arm at the battle of Chancellorsville on Saturday, May 2, 1863, Thomas Jackson underwent amputation of the left arm below the left shoulder. He died 1 week later with a diagnosis of pleuropneumonia. The records of the postsurgical course are incomplete. The available clinical information raises the hypothesis that his chronic dyspepsia and his cause of death could have been related to chronic peptic ulcer disease due to gastric H. pylori infection.

Evaluation of chronic gastrointestinal symptoms following Persian Gulf War exposure

This was a prospective study performed in a Department of Veterans Affairs Medical Center. The aim of this study was to use endoscopic and histological examinations to determine the potential diagnostic origins of chronic gastrointestinal symptoms among patients who were part of the deployment of troops to the Persian Gulf after August 1990. Twenty-four (8%) male patients (mean age, 42 years) of 308 patients in the Persian Gulf War Registry agreed to undergo endoscopic examination of chronic symptoms, including heartburn (29%), dyspepsia (33%), dysphagia (8%), diarrhea (63%), Hemoccult-positive stool (21%), and rectal bleeding (17%). There were 17 upper endoscopies, 18 colonoscopies, and 4 flexible sigmoidoscopies performed, all with biopsies. Five (33%) of 15 patients had positive serological findings for Helicobacter pylori. With upper endoscopy, major findings included esophagitis (12%), Schatzki's ring (12%), hiatal hernia (47%), antral erythema (59%), and duodenal erythema (29%). With lower endoscopy, major findings included ileitis (5%), lymphoid hyperplasia (9%), polyps (27%), diverticulosis (23%), and hemorrhoids (23%). Major histopathological findings included microscopic esophagitis (24%), gastritis with H. pylori (35%), gastritis without H. pylori (18%), Crohn's disease (5%), tubular adenoma (5%), hyperplastic polyps (18%), and melanosis coli (5%). Most patients with chronic heartburn or dyspepsia have evidence of esophagitis or H. pylori. Individuals with these chronic symptoms should undergo evaluation.

Effect of the H, K-ATPase inhibitor, esomeprazole magnesium, on gut total antioxidant capacity in mice

Antioxidant depletion is believed to be a mechanism involved in the pathophysiology of several upper gastrointestinal disorders, and H, K-ATPase inhibitors can alter free radical production by neutrophils. We hypothesized that the H, K-ATPase inhibitor esomeprazole magnesium would decrease gut free radical production with a concomitant increase in gut total antioxidant capacity. A/J mice (n = 10/group) received either vehicle (control) or one of three concentrations of esomeprazole magnesium in vehicle by once-daily gavage for 10 days. Using tissue extracts from stomach and colon, total antioxidant capacity, lipid peroxide levels, and constitutive Cu/Zn-superoxide dismutase were measured using validated assays. There was a dose-related increase in total antioxidant capacity (analysis of variance, P < 0.001) in stomach, but there was no change in the colon. In the assessment of free radical production, there was a trend toward decreased lipid peroxide levels in stomach from mice receiving esomeprazole. In stomach, Cu/Zn-superoxide dismutase activity was increased (ANOVA: p=.03) in mice receiving esomeprazole. In conclusion, gastric total antioxidant capacity and Cu/Zn-superoxide dismutase activity are increased by esomeprazole, and these changes may result in part from decreased free radical production. The present results support the notion that the pharmacological effects of this agent on upper intestinal tissue are more complex than previously thought, and appear to involve both enzymatic and nonenzymatic tissue antioxidants.

Oxidative stress in nonalcoholic fatty liver disease: pathogenesis and antioxidant therapies

Nonalcoholic fatty liver disease is a common cause of chronic liver disease, a common finding on liver biopsy in those patients with abnormal blood transaminase levels, and a common cause of cryptogenic cirrhosis in the United States. The prevalence of this disorder is expected to rise with the increase in obesity, and the clinical spectrum can range from simple steatosis (fatty liver) to cirrhosis of the liver. Insulin resistance is thought to be pivotal for the development of steatosis, and oxidative stress may be a potential factor that can promote hepatic necroinflammation and fibrosis. Preliminary studies have examined the role of oxidative stress and antioxidants in animal and human studies of this disorder. Efforts to improve the hepatic antioxidant system could be achieved by optimizing the patient's diet, by supplementation with precursors for antioxidants, or by supplementation with essential metals and/or antioxidants. Randomized, controlled trials are required to examine these potential approaches using patients with this disorder.

Effects of esomeprazole magnesium on nonsteroidal anti-inflammatory drug gastropathy

It has been proposed that tissue damage induced by nonsteroidal anti-inflammatory drugs is related to increased tissue free radical production with antioxidant depletion. We have shown that esomeprazole increases gastric total antioxidant capacity in mice and, therefore, hypothesized that the protective effect of esomeprazole during treatment with a nonsteroidal anti-inflammatory drug is related to increased gastric antioxidant capacity and decreased tissue free radical production. A/J mice received one of four treatments by daily gavage: saline in vehicle (control), indomethacin, esomeprazole, or indomethacin and esomeprazole. After 10 days, all mice were sacrificed and validated assays were used to measure gastric total antioxidant capacity, lipid peroxide levels, and myeloperoxidase activity. Indomethacin-treated mice developed weight loss and melena. No mice receiving indomethacin and esomeprazole died, but the death rate while receiving indomethacin was 38% (chi2, P = 0.05). Gastric lipid peroxide levels increased in mice receiving indomethacin treatment compared to treatment with esomeprazole and indomethacin (P = 0.03). There was a strong trend (P = 0.08) toward increased gastric total antioxidant capacity in mice receiving esomeprazole and indomethacin compared to mice receiving indomethacin. Gastric myeloperoxidase activities were not different among the four groups. Esomeprazole significantly improved survival in mice that received indomethacin, reduced free radical production, as estimated by lipid peroxide levels, and appeared to increase gastric total antioxidant capacity. The mechanisms for the beneficial effects of esomeprazole in the treatment of gastropathy are more complex than previously thought.

Oxidative Stress in Nonalcoholic Fatty Liver Disease: Pathogenesis and Antioxidant Therapies

Nonalcoholic fatty liver disease is a common cause of chronic liver disease, a common finding on liver biopsy in those patients with abnormal blood transaminase levels, and a common cause of cryptogenic cirrhosis in the United States. The prevalence of this disorder is expected to rise with the increase in obesity, and the clinical spectrum can range from simple steatosis (fatty liver) to cirrhosis of the liver. Insulin resistance is thought to be pivotal for the development of steatosis, and oxidative stress may be a potential factor that can promote hepatic necroinflammation and fibrosis. Preliminary studies have examined the role of oxidative stress and antioxidants in animal and human studies of this disorder. Efforts to improve the hepatic antioxidant system could be achieved by optimizing the patient's diet, by supplementation with precursors for antioxidants, or by supplementation with essential metals and/or antioxidants. Randomized, controlled trials are required to examine these potential approaches using patients with this disorder.

The changing face of esophageal malignancy

Concern has been expressed about the rapid increase in the incidence of esophageal carcinoma in the United States. This rise is due to an increase in the number of cases of adenocarcinoma of the esophagus. Because of the relatively small number of cases of esophageal carcinoma, the absolute risk of developing this cancer in the United States remains small. Potential origins for this increase in esophageal adenocarcinoma are examined in this review, including the risk induced by obesity, low dietary antioxidants, high dietary fat, family history of breast cancer, smoking, gastroesophageal reflux, and Barrett's esophagus. The risk of esophageal adenocarcinoma is inversely associated with infection by Helicobacter pylori organisms. A better understanding of risk factors involved in the increased incidence of esophageal adenocarcinoma is important for development of new preventive strategies for this serious disorder.

Total antioxidant capacity following extrinsic denervation and small intestinal transplantation in the rat

Transplantation of small intestine in a rat model has been shown to affect expression of neurochemicals within enteric inhibitory nerves. However, the mechanism for altered expression of inhibitory neurochemicals is uncertain. Based on our previous studies, we hypothesized that small intestinal transplantation would result in altered intestinal levels of antioxidant capacity. Glutathione, total antioxidant capacity, and lipid peroxide levels were measured at 3 months following (1) transection of rat small intestine, (2) transection and extrinsic denervation of rat intestine, and (3) isotransplantation of rat ileum or (4) allotransplantation of rat ileum with cyclosporine therapy to suppress rejection. Glutathione levels were not significantly different among the four groups. There were trends toward increased lipid peroxide levels following isografting and extrinsic denervation. Total antioxidant capacity was increased following extrinsic denervation (P=0.05). Increased intestinal total antioxidant capacity in response to extrinsic denervation may represent a compensatory mechanism for protection against oxidative stress. This result enhances our understanding of the relationship between tissue antioxidant levels and alteration of enteric nerves.

Effects of omeprazole and ascorbate on gastric emptying and antioxidant levels in a mouse model of glutathione depletion

Increased free radical production with depletion of the antioxidant, glutathione, is a suggested mechanism for the development of ulcer disease in patients with Helicobacter pylori. The effects of ascorbate and omeprazole as potential gut antioxidants are incompletely understood. We hypothesized that as antioxidants, ascorbate and omeprazole protect against glutathione depletion. This study was designed to determine the effects of ascorbate and omeprazole on gastric emptying and gastric antioxidant levels in a mouse model of glutathione depletion. In an acute (10-day) mouse model, glutathione depletion was induced by inhibiting the rate limiting enzyme, gamma-glutamylcysteine synthetase. Enzymatic blockade produced depletion of gastric glutathione (P < 0.05) without increasing gastric lipid hydroperoxides. Glutathione depletion was associated with accelerated liquid gastric emptying. These effects were not prevented by supplementation with ascorbate or omeprazole. Omeprazole induced increased (P < 0.05) gastric and colonic total antioxidant capacity. One of the beneficial effects of omeprazole in patients may involve increased total antioxidant capacity.

Choline acetyltransferase activity parallels the pressure gradient in the feline pharyngo-esophageal region

Pressures generated by the pharyngeal constrictor muscles and proximal esophagus involve acetylcholine-induced muscle contractions. We hypothesized that the pharyngo-esophageal pressure gradient is related to choline acetyltransferase activity. In nine anesthetized cats, hypopharyngeal pressure and proximal esophageal pressure were recorded with a solid state transducer assembly. Enzymatic activities in the thyropharyngeus, cricopharyngeus, and proximal esophageal muscles were measured. Hypopharyngeal pressure was higher than the proximal esophagus (p < 0.01), and choline acetyltransferase activity was higher in the cricopharyngeus compared to the proximal esophagus ( p < 0.05). The pressure gradient between the hypopharynx and proximal esophagus may be influenced by the activity of choline acetyltransferase.