Improvement in glycemic control by gastric electrical stimulation (TANTALUS) in overweight subjects with type 2 diabetes. Surg Endosc. 2009;23:1955-1960. [PMID: 19067068 DOI: 10.1007/s00464-008-0222-4]

Endoscopic Treatment of Obesity and Nutritional Aspects of Bariatric Endoscopy

Obesity is a significant problem worldwide. Several serious diseases that decrease patient quality of life and increase mortality (high blood pressure, dyslipidaemia, type 2 diabetes etc.) are associated with obesity. Obesity treatment is a multidisciplinary and complex process that requires maximum patient compliance. Change of lifestyle is fundamental in the treatment of obesity. While pharmacotherapeutic options are available, their efficacy is limited. Surgical treatment though highly effective, carries the risk of complications and is thus indicated mostly in advanced stages of obesity. Endoscopic treatments of obesity are less invasive than surgical options, and are associated with fewer complications and nutritional deficits. Currently, there is a large spectrum of endoscopic methods based on the principles of gastric volume reduction, size restriction and gastric or small bowel bypass being explored with only few available in routine practice. The aim of this publication is to present an up-to-date summary of available endoscopic methods for the treatment of obesity focusing on their efficacy, safety and nutritional aspects.

A systematic review on neuromodulation therapies for reducing body weight in patients with obesity

The global prevalence of obesity increases yearly along with a rising demand for efficacious, safe, and accessible treatments. Neuromodulation interventions (i.e., deep brain stimulation [DBS], transcranial magnetic stimulation [TMS], transcranial direct current stimulation [tDCS], percutaneous neurostimulation [PENS], vagus nerve stimulation [VNS], and gastric electrical stimulation [GES]) have been proposed as novel therapies. This systematic review sought to examine the safety and efficacy of neuromodulation therapies in reducing body weight in patients with obesity. Using PRISMA guidelines, we performed a systematic review for studies on neuromodulation for the treatment of obesity, resulting in 60 trials included (7 DBS, 5 TMS, 7 tDCS, 17 PENS and VNS, and 24 GES; a total of 3,042 participants). While promising results have been reported in open label studies, double-blinded randomized clinical trials often did not reach their primary endpoints, with no technique inducing a striking reduction in body weight. Bearing in mind the complexity and multifactorial nature of obesity, it is possible that a single treatment may not be enough for patients to lose or maintain the weight lost at long term.

Systematic review on gastric electrical stimulation in obesity treatment

Introduction: Obesity is a very common public health problem worldwide. However, there is a lack of effective therapies. Only a small portion of patients with morbid obesity are accepting bariatric surgery as the last option due to the risks associated with invasive therapy. Areas covered: In this paper, we review an emerging weight loss treatment: gastric electrical stimulation (GES). The feasibility of GES as a potential therapy for obesity is introduced. Methodologies and parameters of GES are presented. Several GES methods for treating obesity and their effects on food intake and body weight are presented. Possible mechanisms involved in the anti-obesity effect of GES are discussed. Finally, our comments on the potential of GES for obesity and expectations for future development of the GES therapy are provided. The PubMed central database was searched from inception to May 2019. The literature search used the following terms: 'Gastric electrical stimulation' combined with 'obesity' and 'Implantable gastric stimulation' and 'pharmaceutical therapy' and 'bariatric surgery'. Expert opinion: There is a potential to use GES for treating obesity. However, more efforts are needed to develop appropriate stimulation devices and to design an adequate therapy for treating obesity in humans.

Use of Bioelectronics in the Gastrointestinal Tract

Gastrointestinal (GI) motility disorders are major contributing factors to functional GI diseases that account for >40% of patients seen in gastroenterology clinics and affect >20% of the general population. The autonomic and enteric nervous systems and the muscles within the luminal GI tract have key roles in motility. In health, this complex integrated system works seamlessly to transport liquid, solid, and gas through the GI tract. However, major and minor motility disorders occur when these systems fail. Common functional GI motility disorders include dysphagia, gastroesophageal reflux disease, functional dyspepsia, gastroparesis, chronic intestinal pseudo-obstruction, postoperative ileus, irritable bowel syndrome, functional diarrhea, functional constipation, and fecal incontinence. Although still in its infancy, bioelectronic therapy in the GI tract holds great promise through the targeted stimulation of nerves and muscles.

Ghrelin, CCK, GLP-1, and PYY(3-36): Secretory Controls and Physiological Roles in Eating and Glycemia in Health, Obesity, and After RYGB

The efficacy of Roux-en-Y gastric-bypass (RYGB) and other bariatric surgeries in the management of obesity and type 2 diabetes mellitus and novel developments in gastrointestinal (GI) endocrinology have renewed interest in the roles of GI hormones in the control of eating, meal-related glycemia, and obesity. Here we review the nutrient-sensing mechanisms that control the secretion of four of these hormones, ghrelin, cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), and peptide tyrosine tyrosine [PYY(3-36)], and their contributions to the controls of GI motor function, food intake, and meal-related increases in glycemia in healthy-weight and obese persons, as well as in RYGB patients. Their physiological roles as classical endocrine and as locally acting signals are discussed. Gastric emptying, the detection of specific digestive products by small intestinal enteroendocrine cells, and synergistic interactions among different GI loci all contribute to the secretion of ghrelin, CCK, GLP-1, and PYY(3-36). While CCK has been fully established as an endogenous endocrine control of eating in healthy-weight persons, the roles of all four hormones in eating in obese persons and following RYGB are uncertain. Similarly, only GLP-1 clearly contributes to the endocrine control of meal-related glycemia. It is likely that local signaling is involved in these hormones' actions, but methods to determine the physiological status of local signaling effects are lacking. Further research and fresh approaches are required to better understand ghrelin, CCK, GLP-1, and PYY(3-36) physiology; their roles in obesity and bariatric surgery; and their therapeutic potentials.

A pilot study to compare meal-triggered gastric electrical stimulation and insulin treatment in Chinese obese type 2 diabetes

BACKGROUND

Gastrointestinal electromodulation therapy is a novel alternative for achieving diabetes control without traditional bariatric surgery. We compared the efficacy of a meal-initiated implantable gastric contractility modulation (GCM) device with that of insulin therapy in obese Chinese type 2 diabetes (T2D) patients, for whom oral antidiabetes drugs (OADs) had failed.

PATIENTS AND METHODS

Sixteen obese (body mass index, 27.5-40.0 kg/m(2)) T2D patients with a glycated hemoglobin (HbA1c) level of >7.5% on maximal doses of two or more OADs were offered either insulin therapy (n=8) or laparoscopic implantation of a GCM (n=8). We compared changes in body weight, waist circumference (WC), and HbA1c level 1 year after surgery.

RESULTS

The GCM and insulin groups had similar baseline body weight and HbA1c. At 12 months, body weight (-3.2±5.2 kg, P=0.043) and WC (-3.8±4.5 cm, P=0.021) fell in the GCM group but not in the insulin group (P<0.05 for between-group difference). At 6 and 12 months, the HbA1c level fell by 1.6±1.1% and 0.9±1.6% (P=0.011), compared with 0.6±0.3% and 0.6±0.3% (P=0.08) for the insulin group (P=0.15 for between-group difference). The mean 24-h systolic blood pressure (BP) fell by 4.5±1.0 mm Hg in the GCM group (P=0.017) but not in the insulin group. The GCM group required fewer antidiabetes medications (P<0.05) and BP-lowering drugs (P<0.05) than the insulin group. A subgroup analysis showed that patients with a triglyceride level of <1.7 mmol/L had a tendency toward a lower HbA1c level (P=0.090) compared with the controls.

CONCLUSIONS

In obese T2D patients for whom OADs had failed, GCM implantation was a well-tolerated alternative to insulin therapy, with a low triglyceride level as a possible predictor for glycemic response.

Neurostimulation of the gastrointestinal tract: review of recent developments

OBJECTIVE

Neurostimulation is one manifestation of neuromodulation of the gastrointestinal (GI) tract. This manuscript reviews the history of neurostimulation of the GI tract with emphasis on current methods of stimulation.

MATERIALS AND METHODS

A review was completed of the current research on GI neurostimulation methods with an emphasis on their clinical applications.

RESULTS

Upper GI disorders can be modulated with both temporary (placed endoscopically or surgically) or permanent (placed surgically) gastric electrical stimulation (GES) devices. The current GI neurostimulation of stomach (GES) devices have been used in both children and adults, and some patients have been followed in excess of 15 years with good long-term results. Similar GES devices also have been used for a variety of lower GI disorders, including constipation and fecal incontinence, for a number of years.

CONCLUSIONS

GI neurostimulation, as a type of neuromodulation, has been demonstrated to function at several locations in the GI tract for a variety of disorders. The future of neurostimulation in the GI tract will likely be influenced by a better understanding of pathophysiology as well as the development of new techniques and devices for neuromodulation.

The DIAMOND system in the treatment of type 2 diabetes mellitus in an obese patient

Obesity and type 2 diabetes mellitus have reached epidemic proportions worldwide. As the majority of antidiabetic medications are of limited efficacy and patient adherence to long-term therapy is one of the main limiting factors of effective blood glucose and body weight control, new therapies are still looked for. The DIAMOND system seems to be one of the most promising among them. This system recognizes natural electrical activity of the stomach and automatically applies electrical stimulation treatment during/after eating with subsequent modulation of signals transmitted to the regulatory centers in the brain in order to provoke an early response of the gut typical of a full meal. We present the case of a 47-year-old obese woman with type 2 diabetes. During treatment with this system, serum glucose and hemoglobin A_1c levels significantly decreased. Body weight loss and waist circumference reduction were observed. Additionally, beneficial effect on lipid profile was found.

Parameter selection and stimulating effects of an adjustable gastric electrical stimulator in dogs

BACKGROUND

Gastric electrical stimulation (GES) has been proposed as a promising therapeutic option in treating obesity for 20 years. Currently, the available device of GES cannot meet the clinical needs. The purpose of this study is to verify the effect of a new type of adjustable gastric electrical stimulator in reducing food intake and body weight.

METHODS

Eight beagle dogs randomly followed GES and sham GES for 3 months in a crossover design. Parameters were adjusted and individualized during the experiment. Symptoms of GES were recorded, and the effective parameters were selected. Resistance to GES was assessed. Food intake and body weight were measured to evaluate the effect of GES.

RESULTS

The effective parameters were varied among the dogs. Resistance to GES was observed in different periods in dogs. Parameters needed to be adjusted every 10.2 ± 2.1 days during the period of GES. Food intake during GES for 3 months was significantly reduced than that during sham GES of 3 months (P < 0.05). With the decreased food intake, body weight was significantly reduced by the end of GES of 3 months compared with that of sham GES of 3 months (P < 0.05).

CONCLUSIONS

Food intake and body weight of dogs are significantly reduced by adjustable GES. Individual parameters and resistance during GES are required to be considered. The new adjustable device may have good prospects of clinical application for obesity.

Fasting plasma triglycerides predict the glycaemic response to treatment of type 2 diabetes by gastric electrical stimulation. A novel lipotoxicity paradigm

BACKGROUND

Non-stimulatory, meal-mediated electrical stimulation of the stomach (TANTALUS-DIAMOND) improves glycaemic control and causes modest weight loss in patients with Type 2 diabetes who are inadequately controlled on oral anti-diabetic medications. The magnitude of the glycaemic response in clinical studies has been variable. A preliminary analysis of data from patients who had completed 6 months of treatment indicated that the glycaemic response to the electrical stimulation was inversely related to the baseline fasting plasma triglyceride level.

METHOD

An analysis of 40 patients who had had detailed longitudinal studies for 12 months.

RESULTS

Twenty-two patients with fasting plasma triglycerides ≤ 1.7 mmol/l had mean decreases in HbA1c after 3, 6 and 12 months of gastric contraction modulation treatment of -15 ± 2.1 mmol/mol (-1.39 ± 0.20%), -16 ± 2.2 mmol/mol (-1.48 ± 0.20%) and -14 ± 3.0 mmol/mol (-1.31 ± 0.26%), respectively. In contrast, 18 patients with fasting plasma triglyceride > 1.7 mmol/l had mean decreases in HbA1c of -7 ± 1.7 mmol/mol (-0.66 ± 0.16%), -5 ± 1.6 mmol/mol (-0.44 ± 0.18%) and -5 ± 1.7 mmol/mol (-0.42 ± 0.16%), respectively. Pearson's correlation coefficient between fasting plasma triglyceride and decreases in HbA1c at 12 months of treatment was 0.34 (P < 0.05). Homeostasis model assessment of insulin resistance was unchanged during 12 months of treatment in patients with high baseline fasting triglycerides, while it progressively improved in patients with low fasting plasma triglycerides. Patients with low fasting plasma triglycerides had a tendency to lose more weight than those with high fasting plasma triglycerides, but this did not achieve statistical significance.

CONCLUSIONS

The data presented suggest the existence of a triglyceride lipotoxic mechanism that interferes with gastric/neural mediated pathways that can regulate glycaemic control in patients with type 2 diabetes. The data suggest the existence of a triglyceride lipotoxic pathway that interferes with gastric/neural mediated pathways that can regulate glycaemic control.

Gastric stimulation for weight loss

The prevalence of obesity is growing to epidemic proportions, and there is clearly a need for minimally invasive therapies with few adverse effects that allow for sustained weight loss. Behavior and lifestyle therapy are safe treatments for obesity in the short term, but the durability of the weight loss is limited. Although promising obesity drugs are in development, the currently available drugs lack efficacy or have unacceptable side effects. Surgery leads to long-term weight loss, but it is associated with morbidity and mortality. Gastric electrical stimulation (GES) has received increasing attention as a potential tool for treating obesity and gastrointestinal dysmotility disorders. GES is a promising, minimally invasive, safe, and effective method for treating obesity. External gastric pacing is aimed at alteration of the motility of the gastrointestinal tract in a way that will alter absorption due to alteration of transit time. In addition, data from animal models and preliminary data from human trials suggest a role for the gut-brain axis in the mechanism of GES. This may involve alteration of secretion of hormones associated with hunger or satiety. Patient selection for gastric stimulation therapy seems to be an important determinant of the treatment’s outcome. Here, we review the current status, potential mechanisms of action, and possible future applications of gastric stimulation for obesity.

Endoscopic treatment of obesity

Obesity is a worldwide epidemic, complex metabolic disease associated with a variety of severe comorbidities. Bariatric surgery provides the patients with the benefits of sustained weight loss and improves obesity-related comorbidities, but can result in potentially life-threatening complications. Gastrointestinal endoscopy has recently been proposed as a scarless and noninvasive approach to obesity. Most of the current endoluminal devices and techniques are comparable to restrictive surgery. A variety of medical devices and procedures have been evaluated in recent years; however, with the exception of the intragastric balloon, evaluation of all the other endoluminal procedures is limited by the numbers of patients treated, the short follow-up and especially by the study design. Today, only a few devices have been evaluated in randomized controlled trials. The preliminary results of the first studies are extremely promising, but definitive statements cannot be drawn yet.

Micro-orifice metabolic/bariatric surgery under IV sedation/local anesthesia: porcine feasibility study

BACKGROUND

As the volume and scope of metabolic/bariatric surgery increases, there is a definite trend toward the development and utilization of simpler and safer procedures. The laparoscopic approach has certain disadvantages that can be avoided by a technique for abdominal access via a micro-orifice incision under intravenous (IV) sedation/local anesthesia, without general anesthesia, insufflation, and intubation.

METHODS

In a porcine model, we used the implantation of the TANTALUS System as a prototype for the micro-orifice, IV sedation/local anesthesia approach. The study was conducted in five ex vivo stomachs, four cadavers, and six in vivo animals, the last four of which underwent surgery under IV sedation/local anesthesia.

RESULTS

Accurate implantation of electrodes was achieved in all ex vivo, cadaver, and in vivo preparations with no mucosal penetration, confirmed by examination of the open porcine stomachs. Operative time in this learning setting was 1 h 43 min in the last three operated animals. Feasibility was established for using the single incision to tunnel and construct subcutaneous pockets for the pulse generator and the charge coil. No major operative or postoperative complications occurred.

CONCLUSIONS

Using the TANTALUS System as a metabolic/bariatric surgery prototype model, this study successfully tested the feasibility of micro-orifice surgery, under IV sedation/local anesthesia. This study will be followed by human trials that may offer an alternative approach for the performance of metabolic/bariatric surgery.

Gastric electrical stimulation with the TANTALUS System in obese type 2 diabetes patients: effect on weight and glycemic control

BACKGROUND

The TANTALUS System is an investigational device that consists of an implantable pulse generator connected to gastric electrodes. The system is designed to automatically detect when eating starts and only then deliver sessions of gastric electrical stimulation (GES) with electrical pulses that are synchronized to the intrinsic antral slow waves. We report the effect of this type of GES on weight loss and glucose control in overweight/obese subjects with type 2 diabetes mellitus (T2DM). This study was conducted under a Food and Drug Administration/Institutional Review Board-approved investigational device exemption.

METHOD

Fourteen obese T2DM subjects on oral antidiabetes medication were enrolled and implanted laparoscopically with the TANTALUS System (body mass index 39 +/- 1 kg/m(2), hemoglobin A1c [HbA1c] 8.5 +/- 0.2%).Gastric electrical stimulation was initiated four weeks after implantation. Weight, HbA1c, fasting blood glucose, blood pressure, and lipid levels were assessed during the study period.

RESULTS

Eleven subjects reached the 6-month treatment period endpoint. Gastric electrical stimulation was well tolerated by all subjects. In those patients completing 6 months of therapy, HbA1c was reduced significantly from 8.5 +/- 0.7% to 7.6 +/- 1%, p < .01. Weight was also significantly reduced from 107.7 +/- 21.1 to 102.4 +/- 20.5 kg, p < .01. The improvement in glucose control did not correlate with weight loss (R(2) = 0.05, p = .44). A significant improvement was noted in blood pressure, triglycerides, and cholesterol (low-density lipoprotein only).

CONCLUSIONS

Short-term therapy with the TANTALUS System improves glucose control, induces weight loss, and improves blood pressure and lipids in obese T2DM subjects on oral antidiabetes therapy.