Implantable gastric stimulation (IGS) as therapy for human morbid obesity: report from the 2001 IFSO symposium in Crete

Single Versus Double Anastomosis Duodenal Switch in the Management of Obesity: A Meta-analysis and Systematic Review

BACKGROUND

Biliopancreatic diversion with duodenal switch (BPD-DS) is an effective yet technically challenging bariatric surgery with many complications. Alternatively, single anastomosis duodenal-ileal bypass with sleeve gastrectomy (SADI-S) was recently introduced as a simplified bariatric procedure. This meta-analysis aimed to assess the safety and efficacy of SADI-S compared with BPD-DS in the management of patients with obesity.

METHODS

Cochrane, Embase, PubMed, Scopus, and Web of Science were searched for articles from their inception to May 2022 by 2 independent reviewers using the Preferred Reporting Items for Systematic Reviews and Meta-analysis system. The review was registered prospectively with PROSPERO (CRD42022333521).

RESULTS

From 123 studies screened, 6 studies met the eligibility criteria, with a total of 1847 patients with obesity undergoing either SADI-S (n=818) or BPD-DS (n=1029). Preoperative body mass index was similar between the 2 groups, and the BPD-DS group had a greater % excess body mass index loss (EBMIL) (MD=-10.16%, 95% confidence interval: -11.80, -8.51, I2=0%) at 2 years compared with the SADI-S group. There was no difference observed in preoperative comorbidities and remission, including diabetes, hypertension, and dyslipidemia between SADI-S and BPD-DS cohorts. Compared with BPD-DS, SADI-S had shorter hospital stays (MD=-1.36 d, 95% CI: -2.39, -0.33, I2=86%), and fewer long-term (>30 d) complications (OR=0.56, 95% CI: 0.42, 0.74, I2=20%). Conversely, among nutritional deficiency outcomes, the SADI-S group had few patients with abnormal vitamin D (OR=0.51, 95% CI: 0.36, 0.72, I2=0%) values than the BPD-DS group.

CONCLUSIONS

SADI-S has shown to be a possible alternative treatment option to BPD-DS in managing patients with obesity. Despite the promising results, further randomized controlled studies with more extended follow-up periods are necessary to ascertain the safety and efficacy of the treatment.

Intestinal Electrical Stimulation Alters Hypothalamic Expression of Oxytocin and Orexin and Ameliorates Diet-Induced Obesity in Rats

BACKGROUND

Intestinal electrical stimulation (IES) has been proposed as a potential treatment for obesity. The aim of this study was to explore the central mechanism underlying the reduction of food intake and body weight by IES by studying the expression of anorexigenic- and orexigenic-peptide-containing neurons in the hypothalamus.

MATERIALS AND METHODS

Diet-induced obese (DIO) rats were divided into three groups to receive sham, IES, and pair-feeding for 4 weeks. Food intake was measured automatically and presented as daily and body weight measured weekly. The expressions of oxytocin, an anorexigenic neuropeptide, in the paraventricular nucleus of the hypothalamus (PVN) and the supraoptic nuclei of the hypothalamus (SON) and orexin-A, an orexigenic neuropeptide, in the lateral hypothalamic area (LHA) were studied using immunohistochemistry.

RESULTS

Compared with sham, IES reduced daily food intake by 28.3% at week 1, 35.6% at week 2, 15.6% at week 3, and 27.1% at week 4. Consistently, IES reduced body weight by 6.3%, compared with a weight gain of 7.2% in sham, and a slight weight loss of 0.5% in pair-feeding. Compared with sham, IES increased the expression of oxytocin-immunoreactive neurons in PVN and SON. Compared with sham, IES decreased the expression of orexin-immunoreactive neurons in LHA. Rats with pair-feeding also showed a relative decease in weight without any changes in the central hormones.

CONCLUSION

IES reduces food intake and body weight and improves glucose tolerance and insulin sensitivity in DIO rats. Its central mechanisms involve enhancement of anorexigenic peptides and suppression of orexigenic peptides in the hypothalamus.

Evaluation of Weight Loss Indicators and Laparoscopic One-Anastomosis Gastric Bypass Outcomes

Mini-gastric bypass/One-anastomosis gastric bypass (MGB-OAGB) is an effective bariatric technique for treating overweight and obesity, controlling and improving excess-weight-related comorbidities. Our study evaluated OAGB characteristics and resulting weight evolution, plus surgical success criteria based on various excess weight loss indicators. A prospective observational study of 100 patients undergoing OAGB performed by the same surgical team (two-year follow-up). Surgical characteristics were: surgery duration, associated complications, bowel loop length, hospital stay, and weight loss at 6 postoperative points. 100 patients were treated (71 women, 29 men); mean initial age was 42.61 years and mean BMI, 42.61 ± 6.66 kg/m². Mean surgery duration was 97.84 ± 12.54 minutes; biliopancreatic loop length was 274.95 ± 23.69 cm. Average hospital stay was 24 hours in 98% of patients; no surgical complications arose. Weight decreased significantly during follow-up (P < 0.001). Greatest weight loss was observed at 12 months postsurgery (68.56 ± 13.10 kg). Relative weight loss showed significant positive correlation, with greatest weight loss at 12 months and %excess BMI loss > 50% achieved from the 3-month follow-up in 92.46% of patients. OAGB seems to be effective in treating obesity, with short hospital stays. Relative weight loss correlates optimally with absolute outcomes, but both measures should be used to evaluate surgical results.

Food intake and body weight responses to intermittent vs. continuous gastric electrical stimulation in diet-induced obese rats

BACKGROUND

Gastric electrical stimulation (GES) has recently been introduced as a potential therapy for the treatment of obesity. The main challenge for the new generation of devices is to achieve desired clinical outcomes at a suitably low level of energy consumption. The aim of this study is to compare the effectiveness of GES with continuous and intermittent duty cycles in reducing food intake and body weight in diet-induced obesity-prone rats.

METHODS

In macro duty cycle experiment, 40 rats were divided into groups to receive a sham GES, continuous GES, or intermittent GES (15 min On-45 min Off or 15 min On-15 min Off) for 28 days. In micro duty cycle experiment, 18 rats received cross-over treatment of continuous stimulation, 60 % time cycle or 40 % time cycle. Food intake, body weight, gastric emptying and ghrelin level were measured to evaluate the effect of different GES.

RESULTS

GES with macro duty cycle intensity-dependently reduced mean daily food intake increase by 18.6, 10.2 and -6.0 % compared to 42.7 % with sham GES and body weight gain by 6.1 %, 3.4 and -0.8 % compared to 5 % with sham GES. Daily food intake decreased with increasing micro duty cycle intensity, averaging 16.5, 15.6 and 13.7 g/day under 40 % cycle, 60 % cycle and continuous stimulation respectively. Gastric emptying was intensity-dependently delayed by GES. GES has no effect in modulating plasma ghrelin level.

CONCLUSIONS

GES energy-dependently reduces food intake, body weight and gastric emptying. Peripheral modulation of plasma ghrelin level is not related to the GES effects.

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.

Ultrasonic value is not useful to detect bone changes following a biliopancreatic diversion

To study the evolution of the bone mass by ultrasonic transmission after biliopancreatic diversion. Forty eight morbid obese patients were prospectively studied during 36 months following the Larrad biliopancreatic diversion. The bone metabolism was studied by PTHi and the urinary pirydinolines. The bone mass by echography and bone densitometry, which correlate to the levels of PTHi and pyridinolines. After 3 years the bone mass decreased from 50.15 +/- 7.31 kg/m(2), preoperatively, to 34.03 +/- 4.53 kg/m2 (p < 0.001). There was an increase of the PTHi value (from 71.4 +/- 79.6 to 91.65 +/- 43.06 pg/ml) (p = 0.01), and the urinary pirydinolines (from 7.93 +/- 4.06 an 11.4 +/- 10.12 nM/mM) (p < 0.05). The ultrasonic transmission speed increased (from 1,990.93 +/- 62.38 to 2,035.25 +/- 53.98 m/s). However, the bone mineral content (BMC) did not show changes (from 3,016.5 +/- 562.8 to 2,909.6 +/- 304.2 g), as well as the Bone Mineral Density (BMD) (of 1,174.2 +/- 98.8 g/cm2). Neither correlation was found between the BMD (r = 0.212; p = 0.6), the BMC (r =-0.125; p = 0.768), and the T-score (r = 0.592, p = 0.093). The study of the bone mass through ultrasonic transmission speed revealed low sensitivity during the assessment of the morbid obese patients. A percentage of cases of osteopenia were observed despite the fact that they are not reflected in the bone content or in the bone mass. Ultrasonic evaluation of bone mass has no value in the morbidly obese, by the clear negative correlation between ultrasound velocity and thickness of soft tissue.

Effects of cutaneous gastric electrical stimulation on gastric emptying and postprandial satiety and fullness in lean and obese subjects

GOALS

The aim of this study was to investigate the therapeutic potential of cutaneous gastric electrical stimulation (CGES) at a tachygastrial frequency for obesity.

BACKGROUND

Implantable gastric electrical stimulator has been proposed for the treatment of obesity and it has recently been reported that the gastric electrical stimulation at a tachygastrial frequency inhibits gastric motility.

STUDY METHODS

Ten lean and 10 obese healthy volunteers were studied in 3 randomized sessions: no CGES, CGES at the physiologic frequency (3 cycles/min), and CGES at tachygastrial frequency (12 cycles/min). Electrical stimulation was performed using sinusoidal waves. The protocol included the following sequence: 20-minute baseline, 30-minute CGES, 30-minute recording without CGES, 30-minute CGES, ingestion of a 500 kcal liquid meal, and 30-minute CGES. Gastric slow waves were recorded using cutaneous electrogastrography during the periods without CGES. Gastric emptying was assessed by ultrasound. Dyspeptic symptoms were recorded.

RESULTS

(1) The half-time of gastric emptying was longer with CGES at the tachygastrial frequency than CGES at the physiologic frequency in both lean subjects (75.0+/-16.5 min vs. 41.0+/-8.7 min, P<0.01) and obese subjects (64.1+/-13.3 min vs. 32.7+/-5.0 min, P<0.01). (2) Postprandial dyspeptic symptom score (mainly satiety and fullness) was significantly higher with CGES at the tachygastrial frequency than CGES at the physiologic frequency in both lean (3.2+/-1.47 vs. 1.7+/-0.94, P<0.01) and obese (3.9+/-1.89 vs. 1.8+/-1.15, P<0.01) subjects.

CONCLUSIONS

CGES at a tachygastrial frequency enhances postprandial fullness and satiety, and delays gastric emptying. Its therapeutic potential for obesity needs to be studied.

Effects of gastric electric stimulation on gastric distention responsive neurons and expressions of CCK in rodent hippocampus

OBJECTIVE

Gastric electrical stimulation (GES) has been introduced for treating obesity. The hippocampus is known to be involved in the regulation of gastrointestinal motility. Changes in hypathalumus cholecystokinin (CCK) have been observed in genetically obese rodents. This experiment was to study the effect of GES on the activities of neurons and the expression of CCK in the hippocampus.

METHODS AND PROCEDURES

We investigated the effect of GES (GES-I: pulse train of standard parameters; GES-2: reduced train-on time; GES-3: increased pulse width; GES-4: reduced pulse frequency) on neurons responsive to gastric distention (GD) by recording extracellular potentials of single neurons and observing the expression of CCK in the rodent hippocampus by immunohistochemistry staining, radioimmunoassay, and real-time PCR.

RESULTS

92.1% of neurons in the CA2-3 region responded to GD, 53.2% of which showed excitation (GD-E), and 46.8% showed inhibition (GD-I). 64.8% GD-responsive neurons were excited by GES. The response was associated with stimulation strength, pulse width, and frequency; 70.6, 57.1, 94.4, and 66.7% of GD-E and 72.7, 57.1, 86.4, and 50% of GD-I neurons showed excitatory responses to GES-I, -2, -3, and -4, respectively. CCK immunoreactive positive neurons (P<0.001), the content of CCK-like materials (P<0.05) and the amount of CCK mRNA were significantly increased after GES (P<0.05).

DISCUSSION

These findings suggest the central, neuronal, and hormonal mechanisms of GES. GES may excite the activity of GD-sensitive neurons and increase the expression of CCK in the hippocampus. These excitatory effects of GES seem to be related to the parameters of stimulation.

Phosphocalcic Metabolism after Biliopancreatic Diversion

BACKGROUND

Malabsorptive techniques to treat morbid obesity have been followed by alterations in phosphocalcic metabolism. Knowledge of the preoperative situation is important to assess the influence of these techniques on phosphocalcic metabolism and to consider treatments for these alterations.

METHODS

61 consecutive morbidly obese patients (50 women, 11 men, age 19 to 63 years) having had biliopancreatic diversion (BPD) were studied in a prospective manner. Preoperative and postoperative levels of calcium, phosphorus, 25-hydroxyvitamin D, tartrate resistant acid phosphate, plasma parathormone (PTH), tubular absorption of phosphate, and urinary calcium and pyridinolines were analyzed, as well as the potential risk factors for their alterations. Follow-up of all patients was a minimum of 4 years.

RESULTS

Before BPD, 42.3% of patients presented an increase in PTH and 54% a decrease in the 25-OH vitamin D, but the values of calcium and plasma phosphorus maintained at normal level. 81.8% of the patients with an increase in the PTH maintained high levels after BPD, while 60% of those with a normal preoperative PTH also presented hyperparathyroidism 4 years after the intervention. A correlation between the levels of plasma PTH and body mass index was not found.

CONCLUSION

Morbid obesity is accompanied by a high percentage of hyperparathyroidism. BPD produces malabsorption of vitamin D during the first years, favoring the persistence or appearance of hyperparathyroidism. It is important to recognize and treat the secondary hyperparathyroidism. The postoperative period could necessitate more energetic interventions to get more efficient control of the phosphocalcic metabolism.

Characterization of T9-T10 spinal neurons with duodenal input and modulation by gastric electrical stimulation in rats

Gastric electrical stimulation (GES) has been suggested as a therapy for patients with gastric motility disorders or morbid obesity. However, it is unclear whether GES also affects intestinal sensory and motor functions. Furthermore, little is known about intraspinal visceroreceptive transmission and processing for duodenal afferent information. The aims of this study were to characterize responses of thoracic spinal neurons to duodenal distension, to determine the afferent pathway and to examine the effects of GES on activity of these neurons. Extracellular potentials of single T9-T10 spinal neurons were recorded in pentobarbital anesthetized, paralyzed, ventilated male rats (n=19). Graded duodenal distension (DD, 0.2-0.6 ml, 20 s) was produced by water inflation of a latex balloon surgically placed into the duodenum. One pair of platinum electrodes (1.0-1.5 cm apart) was sutured onto the serosal surface of the lesser curvature of the stomach. GES with four sets of parameters was applied for one minute: GES-A (6 mA, 0.3 ms, 40 Hz, 2 s on, 3 s off), GES-B (6 mA, 0.3 ms, 14 Hz, 0.1 s on, 5 s off), GES-C (6 mA, 3 ms, 40 Hz, 2 s on, 3 s off) and GES-D (6 mA, 200 ms, 12 pulses/min). Results showed that 33/117 (28%) spinal neurons responded to noxious DD (0.4 ml, 20 s). Of these, 7 (6%) neurons had low-threshold responses to DD (<or=0.2 ml) and 26 (22%) had high-threshold responses to DD (>or=0.4 ml). DD-responsive spinal neurons were encountered more frequently in deeper (depth: 0.3-1.2 mm) than in superficial laminae (depth: <0.3 mm) of the dorsal horn (24/67 vs. 9/50, P<0.05). DD excited all 9 superficial neurons. In contrast, 20 deeper neurons were excited and 4 neurons were inhibited by DD. Activity of DD-responsive neurons was affected more frequently with GES-C (13/15, 87%) than GES-A (6/16, 38%), -B (3/15, 20%) and -D (5/14, 36%) (P<0.01). Bilateral cervical vagotomy did not significantly alter the effects of DD and GES on 5/5 neurons. Resiniferatoxin (2.0 microg/kg, i.v.), an ultrapotent agonist of transient receptor potential vanilloid receptor-1 (TRPV1), abolished DD responses and GES effects on all neurons examined in vagotomized rats. Additionally, 29/33 (88%) DD-responsive neurons received inputs from somatic receptive fields on the back, flank and medial/lateral abdominal areas. It was concluded that GES mainly exerted an excitatory effect on T9-T10 spinal neurons with duodenal input transmitted by sympathetic afferent fibers expressing TRPV1; spinal neuronal responses to GES were strengthened with an increased pulse width and/or frequency of stimulation; T9-T10 spinal neurons processed input from the duodenum and might mediate effects of GES on duodenal sensation and motility.

Modulatory effects and afferent pathways of gastric electrical stimulation on rat thoracic spinal neurons receiving input from the stomach

Gastric electrical stimulation (GES) has been suggested as a potential therapy for patients with obesity or gastric motility disorders. The aim of this study was to investigate the spinal mechanism of GES effects on gastric functions. Extracellular potentials of single spinal (T9-T10) neurons were recorded in pentobarbital anesthetized, paralyzed, ventilated male rats (n=19). Gastric distension (GD) was produced by air inflation of a balloon. One pair of platinum electrodes (1.0-1.5cm apart) was sutured onto the serosal surface of the lesser curvature of the stomach. GES with four sets of parameters was applied for 1min: GES-A (6mA, 0.3ms, 40Hz, 2s on, 3s off), GES-B (6mA, 0.3ms, 14Hz, 0.1s on, 5s off), GES-C (6mA, 3ms, 40Hz, 2s on, 3s off), GES-D (6mA, 200ms, 12pulses/min). 62/158 (39%) spinal neurons responded to GD (20, 40, 60mmHg, 20s. Most GD-responsive neurons (n=43) had excitatory responses; the remainder had inhibitory (n=12) or biphasic responses (n=7). GES-A, -B, -C and -D affected activity of 12/33 (36%), 4/31 (13%), 22/29 (76%) and 13/30 (43%) GD-responsive neurons, respectively. Bilateral cervical vagotomy did not significantly alter mean excitatory neuronal responses to GD (n=5) or GES (n=6). Resiniferatoxin (2.0microg/kg, i.v.), an ultrapotent agonist of vanilloid receptor-1, abolished excitatory responses to GD and GES in 4/4 neurons recorded in vagotomized rats. The results suggested that GES mainly had an excitatory effect on T9-T10 spinal neurons with gastric inputs; neuronal responses to GES were strengthened with stimulation at an increased pulse width and/or number of pulses. The modulatory effect of GES involved thoracic spinal (sympathetic) afferent fibers containing vanilloid receptor-1.