New device for active gastric mechanical stimulation.

BACKGROUND: Gastroparesis is a chronic stomach disorder and effective treatment is the aim of different strategies. Alternative therapies consist of an electrical stimulation of the stomach to evoke a response in the gastric activity. We present the development and in vivo application of an electromagnet system to induce a mechanical stimulus in the stomach aiming for gastric contractile responses. METHODS: The electromagnet system consisted of an implantable magnet and an external drive coil. We implanted the magnet at the greater curvature of the gastric body in rats. We applied an alternating current to the drive coils, inducing mechanical stimulation of the gastric wall. We measured the gastric contraction activity and gastric electrical activity in response to the stimulus using AC biosusceptometry and electrogastrography. Moreover, we used the phenol red to evaluate the stimulus effects on gastrointestinal transit. KEY RESULTS: The stimulus increased the spectral intensity and signal-to-noise ratio significantly of gastric contraction activity and gastric electrical activity. Furthermore, we found a lower phenol red retention in the stomach in rats without stimulus. No significant differences were found in frequency and root mean square amplitude. CONCLUSIONS & INFERENCES: We developed a new simple electromagnet system that evoked a contraction and gastric electrical response using a mechanical stimulus and decreased gastric emptying time. The system is an accessible tool and may contribute to gastroparesis studies in animals.

Both gastric electrical stimulation and pyloric surgery offer long-term symptom improvement in patients with gastroparesis.

BACKGROUND: Gastroparesis (GP) is hallmarked by nausea, vomiting, and early satiety. While dietary and medical therapy are the mainstay of treatment, surgery has been used to palliate symptoms. Two established first-line surgical options are gastric electrostimulation (GES) and pyloric procedures (PP) including pyloroplasty or pyloromyotomy. We sought to compare these modalities' improvement in Gastroparesis cardinal symptom index (GCSI) subscores and potential predictors of therapy failure. METHODS: All patients undergoing surgery at a single institution were prospectively identified and separated by surgery: GES, PP, or combined GESPP. GCSI was collected preoperatively, at 6 weeks and 1 year. Postoperative GCSI score over 2.5 or receipt of another gastroparesis operation were considered treatment failures. Groups were compared using Pearson's chi-squared and Kruskal-Wallis one-way ANOVA. RESULTS: Eighty-two patients were included: 18 GES, 51 PP, and 13 GESPP. Mean age was 44, BMI was 26.7, and 80% were female. Preoperative GCSI was 3.7. The PP group was older with more postsurgical gastroparesis. More patients with diabetes underwent GESPP. Preoperative symptom scores and gastric emptying were similar among all groups. All surgical therapies resulted in a significantly improved GCSI and nausea/vomiting subscore at 6 weeks and 1 year. Bloating improved initially, but relapsed in the GES and GESPP group. Satiety improved initially, but relapsed in the PP group. Fifty-nine (72%) had surgical success. Ten underwent additional surgery (7 crossed into the GESPP group, 3 underwent gastric resection). Treatment failures had higher preoperative GCSI, bloating, and satiety scores. Treatment failures and successes had similar preoperative gastric emptying. CONCLUSIONS: Both gastric electrical stimulation and pyloric surgery are successful gastroparesis treatments, with durable improvement in nausea and vomiting. Choice of operation should be guided by patient characteristics and discussion of surgical risks and benefits. Combination GESPP does not appear to confer an advantage over GES or PP alone.

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.

Minimally-invasive temporary gastric stimulation: A pilot study to predict the outcome of electronic gastric stimulation with the Enterra™ system.

INTRODUCTION: Gastroparesis (GP) is defined as delayed gastric emptying (GE) without any obstruction of the pylorus. It can be divided into idiopathic, diabetic, post surgical and rare causes. Electronic gastric stimulation (EGS) - Enterra Medtronic™ - is a part of GP therapy. Although its positive impact has been reported in open label trials, randomized controlled trials failed in demonstrating a positive outcome. The aim of this pilot study was to establish a reliable prediction for permanent gastric stimulation. PATIENTS AND PROCEDURE: 6 female patients underwent laparoscopic implantation of 2 temporary electrodes. The Enterra™ system was connected and taped to the skin. Baseline and postoperative gastroparesis cardinal symptom index (GCSI), a validated index for GP therapy, was assessed. Response to EGS was defined as a 50% decrease of baseline GCSI. RESULTS: 4 of 6 patients responded to temporary EGS. 3 of 4 responders underwent permanent implantation. 1 non-responder received a permanent Enterra™ at another institution. After a median follow up time of 9months the responder group GCSI remained low, whereas the non-responder GCSI had increased. Moreover, the health care system was saved € 30,678.03 by this test stimulation concept. CONCLUSION: Laparoscopic implantation of a temporary EGS system predicts the outcome of permanent gastric stimulation and is cost-saving.

Implanted Closed-Loop Gastric Electrical Stimulation (CLGES) System with Sensor-Based Feedback Safely Limits Weight Regain at 24 Months.

BACKGROUND: Weight regain following bariatric surgery is not uncommon. Safe, effective weight loss treatment up to 1 year has been reported with the closed-loop gastric electrical stimulation (CLGES) system. Continuous recording of eating and activity behavior by onboard sensors is one of the novel features of this closed-loop electrical stimulation therapy, and may provide improved long-term weight maintenance by enhancing aftercare. METHODS: Four centers participating in a 12-month prospective multicenter randomized study monitored all implanted participants (n = 47) up to 24 months after laparoscopic implantation of a CLGES system. Weight loss, safety, quality of life (QOL), and cardiac risk factors were analyzed. RESULTS: Weight regain was limited in the 35 (74%) participants remaining enrolled at 24 months. Mean percent total body weight loss (%TBWL) changed by only 1.5% between 12 and 24 months, reported at 14.8% (95% CI 12.3 to 17.3) and 13.3% (95% CI 10.7 to 15.8), respectively. The only serious device-/procedure-related adverse events were two elective system replacements due to lead failure in the first 12 months, while improvements in QOL and cardiovascular risk factors were stable thru 24 months. CONCLUSION: During the 24 month follow-up, CLGES was shown to limit weight regain with strong safety outcomes, including no serious adverse events in the second year. We hypothesize that CLGES and objective sensor-based behavior data combined to produce behavior change. The study supports CLGES as a safe obesity treatment with potential for long-term health benefits. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01448785.

Gastric electrical stimulation with Enterra therapy improves symptoms of idiopathic gastroparesis.

BACKGROUND: Gastric electrical stimulation (GES) is a therapeutic option for intractable symptoms of gastroparesis (GP). Idiopathic GP (ID-GP) represents a subset of GP. AIMS: A prospective, multicenter, double-blinded, randomized, crossover study to evaluate the safety and efficacy of Enterra GES in the treatment of chronic vomiting in ID-GP. METHODS: Thirty-two ID-GP subjects (mean age 39; 81% F, mean 7.7 years of GP) were implanted with GES. The stimulator was turned ON for 1½ months followed by double-blind randomization to consecutive 3-month crossover periods with the device either ON or OFF. ON stimulation was followed in unblinded fashion for another 4.5 months. Twenty-five subjects completed the crossover phase and 21 finished 1 year of follow-up. KEY RESULTS: During the unblinded ON period, there was a reduction in weekly vomiting frequency (WVF) from baseline (61.2%, P < 0.001). There was a non-significant reduction in WVF between ON vs OFF periods (the primary outcome) with median reduction of 17% (P > 0.10). Seventy-five percent of patients preferred the ON vs OFF period (P = 0.021). At 1 year, WVF remained decreased (median reduction = 87%, P < 0.001), accompanied by improvements in GP symptoms, gastric emptying and days of hospitalization (P < 0.05). CONCLUSIONS & INFERENCES: (i) In this prospective study of Enterra GES for ID-GP, there was a reduction in vomiting during the initial ON period; (ii) The double-blind 3-month periods showed a non-significant reduction in vomiting in the ON vs OFF period, the primary outcome variable; (iii) At 12 months with ON stimulation, there was a sustained decrease in vomiting and days of hospitalizations.

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.