Advances in the management of gastroparesis

Efficacy and Safety of Gastric Per-Oral Endoscopic Myotomy (G-POEM): A Systematic Review and Meta-Analysis

BACKGROUND

Gastric per-oral endoscopic myotomy (G-POEM) is an innovative treatment that has become increasingly utilized for patients with refractory gastroparesis. The aim of this systematic review and meta-analysis was to evaluate the safety and effectiveness of G-POEM for the treatment of gastroparesis.

METHODS

Individualized search strategies were developed through February 2021 in accordance with the PRISMA and MOOSE guidelines. This meta-analysis was performed by calculating pooled proportions and mean difference preprocedure and postprocedure with rates estimated using random effects models. Measured outcomes included technical success, clinical success, improvement in gastroparesis cardinal symptom index (GCSI), change in gastric emptying rate, alterations in impedance planimetry (functional lumen imaging probe [FLIP]) assessment, and adverse events.

RESULTS

A total of 20 studies (n=797 patients; 67.41% female) were included. The mean age was 48.92±11.61 y, with an average duration of 4.24±1.11 y since gastroparesis diagnosis. Technical success was 98.47% [(95% CI: 97.14, 99.19); I2 =0.00] with a mean myotomy length of 3.78±1.16 cm. In terms of clinical success, mean preprocedure GCSI scores were 3.38±0.37 and improved significantly postprocedure [weighted mean difference -1.56 (95% CI: -1.89 to -1.24); I2 =82.53; P <0.001]. Gastric retention after 4 hours demonstrated ~50% improvement (preprocedure 43.08±9.24% versus postprocedure 22.97±10.19%; P <0.001). FLIP assessment with 40 mL and 50 mL balloons demonstrated a significant increase in diameter, distensibility index, and cross-sectional area postprocedure (all P <0.05). Procedure-associated adverse events occurred among 10.92% [(95% CI 5.09 to 19.32); I2 =82.85] of patients.

CONCLUSION

G-POEM appears safe and highly effective for the treatment of patients with refractory gastroparesis regardless of symptom predominance or etiology.

Therapeutic effect of a temporary transpyloric stent in refractory post-surgical gastroparesis: a case report

BACKGROUND

Gastroparesis is a syndrome characterized by delayed gastric emptying with associated symptoms. It was reported that the symptoms of diabetic gastroparesis had been greatly improved by transpyloric stent placement. However, the use of stents in benign conditions is considered to be contraindicated because of the increasing risk of complications, such as stent migration, reflux, perforation, bleeding, and, most importantly, new strictures caused by stent-induced tissue hyperplasia. While temporary placement of a self-expanding metallic stent (SEMC) can drastically reduce the risk of complications, few reports are available on the treatment of refractory PSG by temporary transpyloric stent. Does it have a long-term clinical effect after the stent being retrieved?

CASE PRESENTATION

After accepting partial resection of the lesser curvature in another hospital, a patient developed refractory gastroparesis. The symptoms hadn't been improved after long-term drug therapy and balloon dilation therapy. Four months after surgery, a fully covered SEMC was placed by endoscopy in our hospital. Gastroparesis had been greatly improved. Two weeks later, the transpyloric stent was retrieved and the patient didn't show recurrent symptoms. Follow-ups were arranged at 3 months, 6 months and 1 year respectively, and there was no evidence of recurrence was found.

CONCLUSIONS

This case indicates that temporary transpyloric SEMC is a safe, effective and less invasive alternative for post-surgical gastroparesis patients.

The Vomiting Patient: Small Bowel Obstruction, Cyclic Vomiting, and Gastroparesis

Vomiting and abdominal pain are common in patients in the emergency department. This article focuses on small bowel obstruction (SBO), cyclic vomiting, and gastroparesis. Through early diagnosis and appropriate management, the morbidity and mortality associated with SBOs can be significantly reduced. Management of SBOs involves correction of physiologic and electrolyte disturbances, bowel rest and removing the source of the obstruction. Treatment of acute cyclic vomiting is primarily directed at symptom control, volume and electrolyte repletion, and appropriate specialist follow-up. The mainstay of therapy for gastroparesis is metoclopramide.

Identification of domperidone metabolites in plasma and urine of gastroparesis patients with LC-ESI-MS/MS

Domperidone is a prokinetic agent used to treat gastroparesis. Previous studies reported oxidative metabolites of domperidone, detected by radiometric high-performance liquid chromatography or single quadrupole mass spectrometric techniques. Our aim was to identify domperidone Phase I and Phase II metabolites using liquid chromatography combined with electrospray ionization-enabled tandem mass spectrometry. Domperidone metabolites were identified in the plasma and urine of 11 gastroparesis patients currently being treated with domperidone. In addition, oxidative and conjugative metabolites of domperidone were characterized in human liver subcellular fractions. Seven metabolites were detected in vivo. Domperidone was metabolized to two mono-hydroxylated metabolites (M1 and M2), a de-alkylated metabolite (M5) and a di-hydroxylated metabolite (M7). The mono-hydroxylated metabolites were further glucuronidated to M8, M9 and sulfated to M11. To the best of our knowledge, M7, M8, M9 and M11 have not been reported previously. Five additional metabolites were identified in vitro in human subcellular fractions which comprise two additional mono-hydroxylated metabolites (M3 and M4), an alcohol metabolite (M6) possibly formed from an aldehyde intermediate, and other conjugative metabolites (M10 and M12). M6, M10 and M12 have not been characterized previously. In total, 12 domperidone metabolites including 7 new metabolites were identified in the present study. These results allow a better understanding of domperidone disposition in humans.

High glucose down-regulates the expression of endogenous insulin-like growth factor-1 in rat colonic smooth muscle cells

AIM: To investigate the effect of high glucose on the expression of endogenous insulin-like growth factor-1 (IGF-1) in rat colonic smooth muscle cells (SMCs).

METHODS: Rat colonic SMCs were separated, cultured, identified by immunofluorescence staining of α-actin, and divided into three groups: normal glucose group (5.5 mmol/L glucose), mannitol control group (5.5 mmol/L glucose plus 19.5 mmol/L mannitol) and high glucose group (25 mmol/L glucose). After treatment, cell proliferation was determined using Cell Counting Kit-8, and cell cycle analysis was performed by flow cytometry. ELISA was designed to measure the content of IGF-I in SMCs culture supernatants. Real-time quantitative-PCR and Western blotting were performed to analyze the mRNA and protein expression of IGF-1 in SMCs.

RESULTS: Compared to the normal glucose group, treatment with high glucose significantly inhibited the proliferation of rat colonic SMCs (0.494 ± 0.0030 vs 0.597 ± 0.044, P < 0.05), resulted in cell accumulation in the G₁ phase (90.850% ± 0.706% vs 55.202% ± 3.807%, P < 0.05) and a significant decrease in the percentage of cells in the S phase (3.622% ± 0.156% vs 30.780% ± 3.808%, P < 0.05), and decreased the content of IGF-I in SMCs culture supernatants (208.000 ng/L ± 31.443 ng/L vs 265.750 ng/L ± 26.538 ng/L, P < 0.05) and the expression of IGF-I mRNA and protein (2.037 ± 0.196 vs 2.257 ± 0.273; 0.247 ± 0.045 vs 0.906 ± 0.103, both P < 0.05). However, there were no significant differences in the above parameters between the normal glucose group and mannitol control group.

CONCLUSION: High glucose inhibits the proliferation of rat colonic SMCs and decreases the expression of endogenous IGF-1 in SMCs.

Gastroparesis: approach, diagnostic evaluation, and management

Gastroparesis is a chronic motility disorder of the stomach that involves delayed emptying of solids and liquids, without evidence of mechanical obstruction. Although no cause can be determined for the majority of cases, the disease often develops as a complication of abdominal surgeries or because of other underlying disorders, such as diabetes mellitus or scleroderma. The pathophysiology behind delayed gastric emptying is still not well-understood, but encompasses abnormalities at 3 levels--autonomic nervous system, smooth muscle cells, and enteric neurons. Patients will often cite nausea, vomiting, postprandial fullness, and early satiety as their most bothersome symptoms on history and physical examination. Those that present with severe disease may already have developed complications, such as the formation of bezoars or masses of undigested food. In patients suspected of gastroparesis, diagnostic evaluation requires an initial upper endoscopy to rule out mechanical causes, followed by a gastric-emptying scintigraphy for diagnosis. Other diagnostic alternatives would be wireless capsule motility, antroduodenal manometry, and breath testing. Once gastroparesis is diagnosed, dietary modifications, such as the recommendation of more frequent and more liquid-based meals, are encouraged. Promotility medications like erythromycin and antiemetics like prochlorperazine are offered for symptomatic relief. These agents may be frequently changed, as the right combination of effective medications will vary with each individual. In patients who are refractory to pharmacologic treatment, more invasive options, such as intrapyloric botulinum toxin injections, placement of a jejunostomy tube, or implantation of a gastric stimulator, are considered. Future areas of research are based on current findings from clinical studies. New medications, such as hemin therapy, are emerging because of a better understanding of the pathophysiology behind gastroparesis, and present treatment options, such as gastric electric stimulation, are evolving to be more effective. Regenerative medicine and stem cell-based therapies also hold promise for gastroparesis in the near future.

Identification of novel metoclopramide metabolites in humans: in vitro and in vivo studies

Metoclopramide (MCP) is frequently used to treat gastroparesis. Previous studies have documented MCP metabolism, but systematic structural identification of metabolites has not been performed. The aim of this study was to better understand MCP metabolism in humans. For examination of in vivo metabolism, a single oral 20-mg MCP dose was administered to eight healthy male volunteers, followed by complete urine collection over 24 h. In vitro incubations were performed in human liver microsomes (HLM) to characterize metabolism via cytochromes P450 and UDP-glucuronosyltransferases and in human liver cytosol for metabolism via sulfotransferases. Urine and subcellular incubations were analyzed for MCP metabolites on a mass spectrometer with accurate mass measurement capability. Five MCP metabolites were detected in vivo, and five additional metabolites were detected in vitro. The five metabolites of MCP identified both in vitro and in vivo were an N-O-glucuronide (M1), an N-sulfate (M2), a des-ethyl metabolite (M3), a hydroxylated metabolite (M4), and an oxidative deaminated metabolite (M5). To our knowledge, metabolites M1 and M4 have not been reported previously. M2 urinary levels varied 22-fold and M3 levels varied 16-fold among eight subjects. In vitro studies in HLM revealed the following additional metabolites: two ether glucuronides (M6 and M8), possibly on the phenyl ring after oxidation, an N-glucuronide (M7), a carbamic acid (M9), and a nitro metabolite (M10). Metabolites M6 to M10 have not been reported previously. In conclusion, this study describes the identification of MCP metabolites in vivo and in vitro in humans.

Metabolic interactions between prokinetic agents domperidone and erythromycin: an in vitro analysis

This study examined in vitro interaction between domperidone and erythromycin. Both are prescribed for refractory gastroparesis. Domperidone is metabolized via human cytochrome P4503A4. Erythromycin is a CYP3A4 inhibitor. Incubations evaluated domperidone metabolite formation in human liver microsomes and recombinant CYP3A4. Concentration- and time-dependent inhibition of 500 microM domperidone was studied with 2.5-200 microM erythromycin over 10-40 min. Domperidone metabolite (5-hydroxy domperidone, M3) formation was inhibited by erythromycin in a concentration- and time-dependent manner. The K(I) estimate was 18.4 microM in human liver microsomes and 4.1 microM in CYP3A4. Using a model incorporating CYP3A4 hepatic and gut inhibition, in vitro estimates from human liver microsomes and CYP3A4 were used to predict in vivo AUCi/AUC ratios of 2.54 and 4.95, respectively. Significant inhibition of domperidone metabolism by erythromycin occurs. This predicts greater domperidone drug exposure when used with erythromycin. This important drug-drug interaction will be evaluated in future human studies.

Treatment of dysautonomia in extrapyramidal disorders

Although extrapyramidal diseases are commonly thought to solely affect the extrapyramidal motor system, nonmotor symptoms such as behavioural abnormalities, dysautonomia, sleep disturbances and sensory dysfunctions are also frequently observed. Autonomic dysfunction as an important clinical component of extrapyramidal disease (idiopathic Parkinson's disease, multiple system atrophy, progressive supranuclear palsy, dementia with Lewy bodies) is often not formally assessed and thus frequently misdiagnosed. Symptoms of autonomic dysfunction in general impact more on quality of life than motor symptoms. Appropriate symptom-oriented diagnosis and symptomatic treatment as part of an interdisciplinary approach can greatly benefit the patient. Unfortunately, double-blind, randomized, controlled studies are scarce with the consequence that most recommendations are not based on the highest level of evidence. This review elaborates a limited overview on the treatment of cardiovascular, gastrointestinal, urogenital and sudomotor autonomic dysfunction in various extrapyramidal syndromes.

Ghrelin receptor agonist (TZP-101) accelerates gastric emptying in adults with diabetes and symptomatic gastroparesis

BACKGROUND

TZP-101 is a synthetic, selective ghrelin agonist in development for gastroparesis.

AIM

To assess safety and effects of TZP-101 in diabetes patients with symptomatic gastroparesis.

METHODS

Adults with type 1 or type 2 diabetes mellitus received placebo and TZP-101 (80, 160, 320 or 600 microg/kg) infusions in a cross-over manner following a radiolabelled meal. Blood glucose levels were stabilized using a hyperinsulinemic-euglycemic clamp. Primary endpoints were gastric half emptying and latency times. Secondary measures included assessment of gastroparesis symptoms and endocrine responses.

RESULTS

Ten patients with type 1 (n = 7) or 2 (n = 3) diabetes, moderate-to-severe gastroparesis symptoms and > or =29% retention 4 h after a radiolabelled solid meal were enrolled. TZP-101 produced significant reductions in solid meal half-emptying (20%, P = 0.043) and latency (34%, P = 0.037) times vs. placebo. Reductions in overall postmeal symptom intensity (24%) and postprandial fullness (37%) following TZP-101 infusion were not statistically significant. Most adverse events were mild and self-limiting and there were no identifiable differences in numbers or types of adverse events between TZP-101 and placebo.

CONCLUSIONS

This proof-of-concept study demonstrates that the ghrelin agonist TZP-101 is well-tolerated in diabetes patients with moderate-to-severe chronic gastroparesis and shows statistically significant improvements in gastric emptying.

Quality of life and symptomatic response to gastric neurostimulation for gastroparesis

BACKGROUND

Gastroparesis can be a difficult problem with patients suffering from nausea, vomiting, bloating, and pain intractable to medical management. Gastric neurostimulation has been developed as an adjunctive treatment for patients with diabetic and idiopathic gastroparesis unresponsive to pharmacologic and dietary treatment. The purpose of this study is to report symptomatic and quality-of-life response to gastric neurostimulation.

METHODS

This study was approved by the institutional review board, and patients had informed consent. The gastric neurostimulation device (Enterra therapy, Medtronic, Inc., Minneapolis, MN, USA) is approved by the Food and Drug Administration under the Humanitarian Device Exemption. Candidates for placement were patients with either idiopathic or diabetic gastroparesis who had symptomatic failure to dietary changes and to prokinetic and antiemetic drugs. Before placement, the patients' symptoms were recorded, and patients completed the Gastrointestinal Symptom Rating Scale (GSRS, three domains: dyspeptic syndrome, indigestion syndrome, and bowel dysfunction syndrome) and the Short Form-36 (SF-36, eight domains: physical functioning, role-physical, role-emotional, bodily pain, vitality, mental health, social functioning, general health, plus a health transition item). The device was surgically placed using a hybrid laparoscopic/open technique. Patients were followed and adjustments made on the device until satisfactory symptom control was achieved. At that time, patients completed both the GSRS and SF-36, and comparisons were made to preoperative values.

RESULTS

Forty-two patients had the device placed, 29 women, aged 41 (SD +14) years, 24 diabetic patients, 17 idiopathic patients, one postgastrectomy patient. Median follow-up was 12 months (range 1-42 months). There was a 2% immediate postoperative morbidity rate and 7% long-term morbidity rate (device extrusion). Thirty-one patients (74%) responded to gastric neurostimulation of variable degrees. Eleven patients had no response or had worsening symptoms. Of the patients who responded, there were statistically significant improvements in all three domains of the GSRS. Median scores (with interquartile ranges): dyspeptic syndrome, 9 (7-11.5) to 4 (2.5-6), p = 0.02; indigestion syndrome, 5 (2-7) to 4 (0-5), p = 0.05; bowel dysfunction syndrome, 3 (2-3) to 1 (0-1), p = 0.01. In the SF-36, there were statistically significant improvement in the health transition item, 4 (4-5) to 1.5 (1-3), p = 0.01; and social functioning domain, 25 (12.5-62.5) to 75 (50-87.5), p = 0.03.

CONCLUSIONS

Three quarters of gastroparesis patients responded to gastric neurostimulation to variable degrees. Gastrointestinal-specific symptoms are improved in responders. Patients felt that there health and social functioning (SF) improved, although there was no significant difference in the other domains. These results are encouraging considering that these patients had intractable symptoms with no other effective treatments available.