Gastric electrical stimulation for obesity

Effect of Transcutaneous Electrical Nerve Stimulation of T6 Dermatome on Appetite and Weight Reduction in Obese Individuals: A Pilot Study

BACKGROUND

Previous work demonstrated the beneficial effect of T6 dermatomal stimulation by the percutaneous method in managing obesity. However, a simple, cost-effective, and feasible intervention stimulating the dermatome can be a potential solution for obesity care.

OBJECTIVE

The objective of this study was to find the effect of transcutaneous electrical nerve stimulation (TENS) of T6 dermatome on appetite and weight loss in obese individuals.

MATERIAL AND METHODS

In this prospective single-arm experimental study, 20 obese patients received TENS treatment of T6 dermatome for 30 min, once a week and for 12 weeks. Outcome measures such as appetite level in the visual analog scale (VAS), weight in kg, and basal metabolic index (BMI) in kg/m2 were assessed at baseline, 12 weeks -post-intervention, and at 8 weeks of follow-up.

RESULTS

A statistically significant difference in all the variables was found from baseline to 12 weeks of intervention (P < 0.001) and maintained till 8 weeks of follow-up. From pre- to post-treatment, the effect size for appetite reduction was large (>1) while for weight and BMI loss was (0.14, 0.16), respectively small. Additionally, a weak correlation was found between pre- and follow-up appetite and weight loss (r = 0.25, P = 0.294).

CONCLUSIONS

Twelve weeks of TENS treatment of T6 dermatome showed a positive effect in reducing appetite with sustained reduction up to 8 weeks of follow-up even after completion of the intervention. However, in the absence of dietary modification, TENS treatment was associated with low effect sizes weight and BMI loss.

Electroceuticals for Neurogastroenterology and Motility Disorders

PURPOSE OF REVIEW

To provide an updated overview on use of electrostimulation in gastrointestinal motility disorders and obesity, with a focus on gastric electrical stimulation, vagal nerve stimulation and sacral nerve stimulation.

RECENT FINDINGS

Recent studies on gastric electrical stimulation for chronic vomiting showed a decrease in frequency of vomiting, but without significant improvement in quality of life. Percutaneous vagal nerve stimulation shows some promise for both symptoms of gastroparesis and IBS. Sacral nerve stimulation does not appear effective for constipation. Studies of electroceuticals for treatment of obesity have quite varied results with less clinical penetrance of the technology. Results of studies on the efficacy of electroceuticals have been variable depending on pathology but this area remains promising. Improved mechanistic understanding, technology and more controlled trials will be helpful to establish a clearer role for electrostimulation in treatment of various GI disorders.

Miniaturized wireless gastric pacing via inductive power transfer with non-invasive monitoring using cutaneous Electrogastrography

BACKGROUND

Gastroparesis is a debilitating disease that is often refractory to pharmacotherapy. While gastric electrical stimulation has been studied as a potential treatment, current devices are limited by surgical complications and an incomplete understanding of the mechanism by which electrical stimulation affects physiology.

METHODS

A leadless inductively-powered pacemaker was implanted on the gastric serosa in an anesthetized pig. Wireless pacing was performed at transmitter-to-receiver distances up to 20 mm, frequency of 0.05 Hz, and pulse width of 400 ms. Electrogastrogram (EGG) recordings using cutaneous and serosal electrode arrays were analyzed to compute spectral and spatial statistical parameters associated with the slow wave.

RESULTS

Our data demonstrated evident change in EGG signal patterns upon initiation of pacing. A buffer period was noted before a pattern of entrainment appeared with consistent and low variability in slow wave direction. A spectral power increase in the EGG frequency band during entrainment also suggested that pacing increased strength of the slow wave.

CONCLUSION

Our preliminary in vivo study using wireless pacing and concurrent EGG recording established the foundations for a minimally invasive approach to understand and optimize the effect of pacing on gastric motor activity as a means to treat conditions of gastric dysmotility.

Multicenter, Phase 1, Open Prospective Trial of Gastric Electrical Stimulation for the Treatment of Obesity: First-in-Human Results with a Novel Implantable System

Background and Aims

To assess safety of the Exilis™ gastric electrical stimulation (GES) system and to investigate whether the settings can be adjusted for comfortable chronic use in subjects with morbid obesity. Gastric emptying and motility and meal intake were evaluated.

Method

In a multicenter, phase 1, open prospective cohort study, 20 morbidly obese subjects (17 female, mean BMI of 40.8 ± 0.7 kg/m²) were implanted with the Exilis™ system. Amplitude of the Exilis™ system was individually set during titration visits. Subjects underwent two blinded baseline test days (GES ON vs. OFF), after which long-term, monthly follow-up continued for up to 52 weeks.

Results

The procedure was safe, and electrical stimulation was well tolerated and comfortable in all subjects. No significant differences in gastric emptying halftime (203 ± 16 vs. 212 ± 14 min, p > 0.05), food intake (713 ± 68 vs. 799 ± 69 kcal, p > 0.05), insulin AUC (2448 ± 347 vs. 2186 ± 204, p > 0.05), and glucose AUC (41 ± 2 vs.41 ± 2, p > 0.05) were found between GES ON and OFF. At week 4, 13, and 26, a significant (p < 0.01) reduction in weight loss was observed but not at week 52. At this time point, the mean excess weight loss (EWL) was 14.2 ± 4.5%.

Conclusion

Gastric electrical stimulation with the Exilis™ system can be considered as safe. No significant effect on food intake, gastric emptying, or gastric motility was observed. The reduction in weight loss with Exilis™ GES was significant but short lasting. Further electrophysiological research is needed to gain more insight in optimal stimulation parameters and lead localization.

The yield, effectiveness and safety of gastroscopy in management of early postbariatric upper gastrointestinal pain

BACKGROUND

Upper gastrointestinal (GI) symptoms are prevalent among patients after -bariatric surgeries. Gastroscopy is an important procedure to investigate symptoms. Our primary aim was to evaluate the yield, effectiveness and safety of gastroscopy procedure obtained in a 3-months period after bariatric operation for exploring upper GI symptoms origin.

METHODS

Single center, retrospective study at the EMMS Nazareth Hospital from 2010 to 2018. All patients who underwent gastric-bypass (either Roux-en-Y[R-en-Y] or Mini-gastric bypass [MGB]) and who experienced early upper GI symptoms were included in the study.

RESULTS

A total of 428 were included in the study. Among them, 154 patients (36%) underwent R-en-Y surgery and 274 (64%) underwent MGB. Baseline characteristics were similar in the two groups. The mean age in the R-en-Y group was 42.3±10.8 vs. 42.8±11.2 in the MGB group. Thirty-nine patients underwent gastroscopy, more in the R-en-Y group compared to MGB group (11.6% vs. 7.6%, P<0.005). In the MGB group, more patients had normal surgical anatomy (23.1%) vs. 12.8% in the R-en-Y group, and the prevalence of erosive esophagitis was 14.2% in the MBG group vs. 5.5% in the R-en-Y group, P<0.005. On the other hand, marginal ulcer was more frequent after R-en-Y than MGB surgery (16.6% vs. 9.5%, P<0.005). No procedural related complication was observed in both groups.

CONCLUSIONS

Upper GI symptoms in the early postbariatric surgery period are common with most endoscopic examination revealing normal postsurgical anatomy. In this setting, gastroscopy is safe, without procedural related complications.

Intestinal Electrical Stimulation to Increase the Rate of Peristalsis

BACKGROUND

Pediatric gastrointestinal motility disorders are a large and broad group. Some of these disorders have been effectively treated with electrical stimulation. The goal of our present study is to determine whether the rate of intestinal peristalsis can be increased with electrical stimulation.

METHODS

Juvenile mini-Yucatan pigs were placed under general anesthesia and a short segment of the jejunum was transected. Ultrasound gel was placed inside the segment. The segment of the jejunum was first monitored for 20 min under no stimulation, followed by direct electrical stimulation using a planar electrode. The gel extruded out of the intestine via peristalsis was collected and weighed for each 20-min time interval.

RESULTS

Effective delivery of the current to the intestine was confirmed via direct measurements. When there was no direct intestinal electrical stimulation, an average of 0.40 g of gel was expelled in 20 min, compared to 1.57 g of gel expelled during direct electrical stimulation (P < 0.01).

CONCLUSIONS

Direct intestinal electrical stimulation accelerates the transit of gastrointestinal contents. This approach may be useful in the treatment of a range of pediatric motility disorders.

Recent Trends in Endoscopic Bariatric Therapies

Obesity and its associated metabolic diseases including diabetes mellitus are severe medical problems that are increasing in prevalence worldwide and result in significant healthcare expenses. While behavioral and pharmacological treatment approaches are partly effective in the short term, their effects are not long-lasting. Although previous studies have described bariatric surgery as the most effective treatment for obesity, it is associated with morbidity, mortality, and economic burden. Endoluminal interventions performed entirely using gastrointestinal flexible endoscopy offer alternative approaches to the treatment of obesity that are safer and more cost-effective than current surgical approaches. The use of endoluminal techniques in the field of metabolic obesity disease has diverse promising applications including endoscopic gastroplasty, intragastric balloon, endoluminal malabsorptive bariatric procedures, and gastric electrical stimulation (GES) for the modulation of gastric emptying. This review discusses recent trends and roles in endoscopic bariatric therapies using the currently available endoluminal and transgastric technologies.

Future Therapies in Obesity

Although diet and exercise have been the cornerstone of therapy for obesity, efficacy is suboptimal and short lived. Surgical procedures are durable but invasive therapy for obesity. Supplemental therapies for obesity that are minimally invasive, low risk, and effective are needed. Several therapeutic options are being developed that offer obese patients and their health care providers alternatives to what is currently available.

Chronic gastric electrical stimulation leads to weight loss via modulating multiple tissue neuropeptide Y, orexin, α-melanocyte-stimulating hormone and oxytocin in obese rats

OBJECTIVES

Gastric electrical stimulation (GES) has great potential for the treatment of obesity. We investigated the impact of chronic GES on the alteration of adipose tissue and the regulation of neuropeptide Y (NPY), orexin (OX), α-melanocyte-stimulating hormone (α-MSH) and oxytocin (OXT), and their receptors in several tissues.

MATERIAL AND METHODS

Most of the experiments included three groups of diet-induced obesity rats: (1) sham-GES (SGES); (2) GL-6mA (GES with 6 mA, 4 ms, 40 Hz, 2 s on, 3 s off at lesser curvature); and (3) SGES-PF (SGES rats receiving pair feeding to match the consumption of GL-6mA rats). Chronic GES was applied for 2 h every day for 4 weeks. During treatment with GES, food intake and body weight were monitored weekly. The alteration of epididymal fat weight, gastric emptying, and expression of peptides and their receptors in several tissues were determined.

RESULTS

GL-6mA was more potent than SGES-PF in decreasing body weight gain, epididymal fat tissue weight, adipocyte size and gastric emptying. Chronic GES significantly altered NPY, OX, α-MSH and OXT and their receptors in the hypothalamus, adipose tissue and stomach.

CONCLUSIONS

Chronic GES effectively leads to weight loss by reducing food intake, fat tissue weight and gastric emptying. NPY, α-MSH, orexin and OXT, and their receptors in the hypothalamus, adipose tissue and stomach appear to be involved in the anti-obesity effects of chronic GES.

Contrasting effects of afferent and efferent vagal nerve stimulation on insulin secretion and blood glucose regulation

Parasympathetic activation reduces hepatic glucose release and increases pancreatic insulin secretion in hyperglycemic conditions. Thus, vagal nerve stimulation (VNS) may potentially be effective in treating type II diabetes. To investigate this possibility, we hypothesized that VNS reduces blood glucose concentration [Glu] via insulin secretion. [Glu] together with insulin and glucagon serum concentrations were determined in anesthetized rats during baseline conditions and 120 min of cervical VNS with the nerve left intact for combined afferent and efferent VNS (n = 9) or the nerve sectioned proximal or distal from the stimulation electrode for selective efferent (n = 8) or afferent (n = 7) VNS, respectively. Afferent VNS caused a strong and sustained increase in [Glu] (+108.9 ± 20.9% or +77.6 ± 15.4%, after 120 min of combined afferent and efferent VNS or selective afferent VNS) that was not accompanied by an increase in serum insulin concentration. However, serum insulin levels increased significantly with selective efferent VNS (+71.2 ± 27.0% after 120 min of VNS) that increased [Glu] only temporarily (+28.8 ± 11.7% at 30 min of VNS). Efferent VNS initially increased serum glucagon concentration which remained elevated for 120 min when efferent VNS was combined with afferent VNS, but returned to baseline with selective efferent VNS. These findings demonstrate that afferent VNS causes a marked and sustained increase in [Glu] that is partly mediated by suppression of pancreatic insulin secretion. In contrast, efferent VNS stimulates pancreatic glucagon secretion that appears to be antagonized by insulin secretion in the case of selective efferent VNS. Selective efferent VNS may potentially be effective in treating type II diabetes.