Is the enteric nervous system a lost piece of the gut-kidney axis puzzle linked to chronic kidney disease?

The enteric nervous system (ENS) regulates numerous functional and immunological attributes of the gastrointestinal tract. Alterations in ENS cell function have been linked to intestinal outcomes in various metabolic, intestinal, and neurological disorders. Chronic kidney disease (CKD) is associated with a challenging intestinal environment due to gut dysbiosis, which further affects patient quality of life. Although the gut-related repercussions of CKD have been thoroughly investigated, the involvement of the ENS in this puzzle remains unclear. ENS cell dysfunction, such as glial reactivity and alterations in cholinergic signaling in the small intestine and colon, in CKD are associated with a wide range of intestinal pathways and responses in affected patients. This review discusses how the ENS is affected in CKD and how it is involved in gut-related outcomes, including intestinal permeability, inflammation, oxidative stress, and dysmotility.

Nasopharyngeal airway assistance improves esophageal intubation rates of high-resolution esophageal manometry catheters.

BACKGROUND: High-resolution esophageal manometry (HREM) is the gold standard test for esophageal motility disorders. Nasopharyngeal airway-assisted insertion of the HREM catheter is a suggested salvage technique for failure from the inability to pass the catheter through the upper esophageal sphincter (UES). It has not been demonstrated that the nasopharyngeal airway improves procedural success rate. METHODS: Patients undergoing HREM between March 2019 and March 2023 were evaluated. Chart review was conducted for patient factors and procedural success rates before and after use of nasopharyngeal airway. Patients from March 2019 to May 2021 did not have nasopharyngeal airway available and were compared to patients from May 2021 to March 2023 who had the nasopharyngeal airway available. KEY RESULTS: In total, 523 HREM studies were conducted; 234 occurred prior to nasopharyngeal airway availability, and 289 occurred with nasopharyngeal airway availability. There was no difference in HREM catheter UES intubation rates between periods when a nasopharyngeal airway attempt was considered procedural failure (85% vs. 85%, p = 0.9). Nasopharyngeal airway use after UES intubation failure lead to improved UES intubation rates (94% vs. 85%, p < 0.01). Thirty-six patients that failed HREM catheter UES intubation had the procedure reattempted with a nasopharyngeal airway, 30 (83%) of which were successful. The nasopharyngeal airway assisted catheter UES intubation for failures attributed to nasal pain and hypersensitivity, gagging, coughing, and pharyngeal coiling. CONCLUSIONS & INFERENCES: Utilization of the nasopharyngeal airway increased rates of UES intubation. When HREM catheter placement through the UES fails, placement of a nasopharyngeal airway can be trialed to overcome patient procedural intolerance.

The gut microbiota in adults with chronic intestinal failure.

OBJECTIVE: Fecal microbiota was investigated in adult patients with chronic intestinal failure (CIF) due to short bowel syndrome (SBS) with jejunocolonic anastomosis (SBS-2). Few or no data are available on SBS with jejunostomy (SBS-1) and CIF due to intestinal dysmotility (DYS) or mucosal disease (MD). We profiled the fecal microbiota of various pathophysiological mechanisms of CIF. METHODS: Cross-sectional study on 61 adults with CIF (SBS-1 30, SBS-2 17, DYS 8, MD 6). Fecal samples were collected and profiled by 16S rRNA amplicon sequencing. Healthy controls (HC) were selected from pre-existing cohorts, matched with patients by sex and age. RESULTS: Compared to HC, SBS-1, SBS-2 and MD patients showed lower alpha diversity; no difference was found for DYS. In beta diversity analysis, SBS-1, SBS-2 and DYS groups segregated from HC and from each other. Taxonomically, the CIF groups differed from HC even at the phylum level. In particular, CIF patients' microbiota was dominated by Lactobacillaceae and Enterobacteriaceae, while depleted in typical health-associated taxa belonging to Lachnospiraceae and Ruminococcaceae. Notably, compositional peculiarities of the CIF groups emerged. Furthermore, in the SBS groups, the microbiota profile differed according to the amount of parenteral nutrition required and the duration of CIF. CONCLUSIONS: CIF patients showed marked intestinal dysbiosis with microbial signatures specific to the pathophysiological mechanism of CIF as well as to the severity and duration of SBS.

Utility of colonic manometry in children with Hirschsprung disease.

OBJECTIVES: Abnormal motility of the residual colon has been reported in post-pull-through Hirschsprung disease (PT-HSCR) patients with persistent defecation problems. We reviewed the role of colonic manometry (CM) in the management of defecation disorders in these patients. METHODS: We retrospectively reviewed the medical record of PT-HSCR children who underwent CM for persistent symptoms of abnormal defecation. We reviewed their clinical course and its relation to CM findings. RESULTS: Thirty PT-HSCR patients underwent CM, of which five were diagnosed with transition zone pull-through and were excluded. Of the remaining 25 patients, 16 had colonic dysmotility, 8 had normal CM, and one had colonic hypermotility. In patients with dysmotility, five responded to ongoing medical management, three required surgical intervention (ileostomy), three remained symptomatic with medical management but not yet received surgical intervention, and five were lost to follow-up. In patients with normal CM, four responded to ongoing medical therapy, two required additional surgery (antegrade enema procedure), and two were lost to follow-up. The patient with hypermotility improved with adding loperamide. CONCLUSIONS: Colonic dysmotility can occur in PT-HSCR patients with persistent defecation problems. CM was helpful in delineating the degree of colonic neuromuscular dysfunction. CM results were used in conjunction with other clinical data to determine optimal management. Our findings support that medical management should first be optimized before consideration of colonic manometry and surgical interventions.

Dysphagia as a Manifestation of Endocrine and Metabolic Disorders.

Dysphagia is a common manifestation of endocrine and metabolic diseases. Swallowing is a complex neuromuscular process, with an interplay of sensory and motor function, that has voluntary and involuntary control. Disruptions in any of these processes can cause significant dysphagia. Endocrine disorders and metabolic derangements are systemic conditions that affect multiple organ systems. They contribute to the development of neuropathies, myopathies, and motility disorders that lead to swallowing difficulty. Malnutrition and critical illness can lead to deconditioning and atrophy which can cause dysphagia, which in turn can lead to further malnutrition and deconditioning.

Safety of prolonged use of metoclopramide and domperidone as treatment for chronic gastrointestinal dysmotility disorders in patients with systemic sclerosis.

Background: Metoclopramide and domperidone are prokinetic agents commonly used to treat gastrointestinal dysmotility disorders. This study aimed to evaluate the safety and associated side effects of prolonged-use metoclopramide and domperidone as treatment for chronic gastrointestinal dysmotility disorders in patients with systemic sclerosis (SSc). Methods: A quantitative observational survey was conducted by interview questionnaire in rheumatology outpatients at a tertiary teaching hospital in Riyadh, Saudi Arabia. The study included all patients aged 25-80 years diagnosed with SSc. All patients were on metoclopramide or domperidone for the treatment of chronic gastrointestinal dysmotility symptoms over at least 12 weeks. Results: Eighteen eligible patients were included. Most study participants were diagnosed with SSc complicated by interstitial lung disease (n = 13; 72.2 %). The most frequently reported side effect that occurred while taking prokinetic drugs was shortness of breath (n = 12; 66.7 %). None of the participants reported experiencing depression, galactorrhea, or syncope. CNS side effects were reported in 5.6 %. There were no differences in side effects based on the type and dosage of prokinetic drug used. Conclusions: Use of metoclopramide and domperidone for the treatment of chronic gastrointestinal dysmotility in SSc patients for 12 weeks or longer was not associated with any troublesome side effects. Further studies with more participants are needed to confirm our findings.

Paraneoplastic autonomic neuropathies and GI dysmotility.

A number of the well-recognized autoimmune and paraneoplastic neurologic syndromes commonly involve the autonomic nervous system. In some cases, the autonomic nerves or ganglia are primary targets of neurologic autoimmunity, as in immune-mediated autonomic ganglionopathies. In other disorders such as encephalitis, autonomic centers in the brain may be affected. The presence of autonomic dysfunction (especially gastrointestinal dysmotility) is sometimes overlooked even though this may contribute significantly to the symptom burden in these paraneoplastic disorders. Additionally, recognition of autonomic features as part of the clinical syndrome can help point the diagnostic evaluation toward autoimmune and paraneoplastic etiologies. As with other paraneoplastic disorders, the clinical syndrome and the presence and type of neurologic autoantibodies help to secure the diagnosis and direct the most appropriate investigation for malignancy. Optimal management for these conditions typically includes aggressive treatment of the neoplasm, immunomodulatory therapy, and symptomatic treatments for orthostatic hypotension and gastrointestinal dysmotility.

Transcutaneous vagal nerve stimulation for treating gastrointestinal symptoms in individuals with diabetes: a randomised, double-blind, sham-controlled, multicentre trial.

AIMS/HYPOTHESIS: Diabetic gastroenteropathy frequently causes debilitating gastrointestinal symptoms. Previous uncontrolled studies have shown that transcutaneous vagal nerve stimulation (tVNS) may improve gastrointestinal symptoms. To investigate the effect of cervical tVNS in individuals with diabetes suffering from autonomic neuropathy and gastrointestinal symptoms, we conducted a randomised, sham-controlled, double-blind (participants and investigators were blinded to the allocated treatment) study. METHODS: This study included adults (aged 20-86) with type 1 or 2 diabetes, gastrointestinal symptoms and autonomic neuropathy recruited from three Steno Diabetes Centres in Denmark. Participants were randomly allocated 1:1 to receive active or sham stimulation. Active cervical tVNS or sham stimulation was self-administered over two successive study periods: 1 week of four daily stimulations and 8 weeks of two daily stimulations. The primary outcome measures were gastrointestinal symptom changes as measured using the gastroparesis cardinal symptom index (GCSI) and the gastrointestinal symptom rating scale (GSRS). Secondary outcomes included gastrointestinal transit times and cardiovascular autonomic function. RESULTS: Sixty-eight participants were randomised to the active group, while 77 were randomised to the sham group. Sixty-three in the active and 68 in the sham group remained for analysis in study period 1, while 62 in each group were analysed in study period 2. In study period 1, active and sham tVNS resulted in similar symptom reductions (GCSI: -0.26 ± 0.64 vs -0.17 ± 0.62, p=0.44; GSRS: -0.35 ± 0.62 vs -0.32 ± 0.59, p=0.77; mean ± SD). In study period 2, active stimulation also caused a mean symptom decrease that was comparable to that observed after sham stimulation (GCSI: -0.47 ± 0.78 vs -0.33 ± 0.75, p=0.34; GSRS: -0.46 ± 0.90 vs -0.35 ± 0.79, p=0.50). Gastric emptying time was increased in the active group compared with sham (23 min vs -19 min, p=0.04). Segmental intestinal transit times and cardiovascular autonomic measurements did not differ between treatment groups (all p>0.05). The tVNS was well-tolerated. CONCLUSIONS/INTERPRETATION: Cervical tVNS, compared with sham stimulation, does not improve gastrointestinal symptoms among individuals with diabetes and autonomic neuropathy. TRIAL REGISTRATION: ClinicalTrials.gov NCT04143269 FUNDING: The study was funded by the Novo Nordisk Foundation (grant number NNF180C0052045).

Role of autoantibodies in the pathophysiology of irritable bowel syndrome: a review.

Irritable bowel syndrome (IBS) is a chronic, recurrent disorder that is characterized by abdominal pain associated with defecation. IBS was previously considered to manifest without any structural alterations until the discovery of post-infection IBS. An increasing body of published evidence indicates that immune activation plays an important role in the development of IBS. Nevertheless, the pathophysiology of IBS, including mainly visceral hypersensitivity and gastrointestinal dysmotility, has not yet been explicitly elucidated. The observation of potential inflammatory degenerative neuropathy, including neuronal degeneration, spearheaded research on autoimmune responses targeting the enteric nervous system. Subsequently, several autoantibodies were detected in the sera of IBS patients, among which some were presumed to exert a pathogenic influence or be associated with the etiology of gastrointestinal dysmotility in IBS. Moreover, certain specific autoantibodies evidently served as biomarkers to facilitate the differentiation between IBS and other related diseases. Therefore, we aimed to present an overview of autoantibodies reported in the sera of IBS patients and highlight their significance in diagnosing and comprehending the pathophysiology of IBS. Consequently, we propose a therapeutic strategy from an autoimmune perspective.

Short-term results of laparoscopic anti-reflux surgery with the RefluxStop device in patients with gastro-esophageal reflux disease and ineffective esophageal motility.

PURPOSE: In gastro-esophageal reflux disease (GERD) requiring surgical treatment, concomitant ineffective esophageal motility (IEM) is a decisive factor in surgical planning, due to concern regarding dysphagia. Anti-reflux surgery with the RefluxStop device is a promising technique. We assessed initial feasibility and clinical outcomes of RefluxStop surgery in patients with GERD and IEM. METHODS: Retrospective analysis of patients with GERD, hiatal hernia (HH), and IEM, who underwent surgery with RefluxStop at our institution and achieved 12-month follow-up. Technique feasibility was assessed, in addition to symptom resolution (GERD-HRQL questionnaire), adverse events, HH recurrence, dysphagia, and patient satisfaction. Placement of the device was confirmed by video fluoroscopy on postoperative day 1, and at 3 and 12 months. RESULTS: Between June 2020 and November 2022, 20 patients with IEM underwent surgery with RefluxStop and completed 12-month follow-up. All patients reported typical symptoms of GERD, and 12 had preoperative dysphagia. The median HH length was 4.5 cm (IQR, 3.75-5). The median operating time was 59.5 min (IQR, 50.25-64) with no implant-related intra- or postoperative complications. No HH recurrence was observed. One patient reported persistent left-sided thoracic pain at 11 months post-surgery, which required diagnostic laparoscopy and adhesiolysis. Three patients reported severe postoperative dysphagia: balloon dilatation was performed towards resolution. The mean GERD-HRQL scores improved (from 40.7 at baseline to 4.8 at 3 months and 5.7 at 12 months (p <0.001)). CONCLUSION: RefluxStop surgery was feasible and offered effective treatment for this group of patients with GERD and IEM. All patients had complete resolution or significant improvement of GERD symptoms, and 90% of them were satisfied with their quality of life 1 year after surgery.

The current state of gastrointestinal motility evaluation in cystic fibrosis: a comprehensive literature review.

Background and Objective: As life expectancy in cystic fibrosis (CF) has increased over the years, a shift in focus toward extra-pulmonary comorbidities such as gastrointestinal (GI) disease has become a topic of particular importance. Although not well-defined in the current literature, GI dysmotility is thought to significantly contribute to GI symptomatology in the CF population. The objective of this article was to provide a comprehensive review of diagnostic modalities at the disposal of the clinician in the evaluation of patients with CF (pwCF) presenting with GI complaints. Furthermore, we aimed to highlight the available literature regarding utilization of these modalities in CF, in addition to their shortcomings, and emphasize areas within the motility literature where further research is essential. Methods: A comprehensive review of all available literature in the English language through December 1, 2022 utilizing PubMed was conducted. Our search was limited to GI motility/transit and dysmotility in pwCF. Two researchers independently screened references for applicable articles and extracted pertinent data. Key Content and Findings: Several diagnostic imaging and manometry options exist in the evaluation of dysmotility; however, the literature is lacking in high-quality, prospective studies to validate such testing in pwCF. Common symptoms experienced and diagnostic motility tools available based on segment of the GI tract as related to pwCF are explored in the current review. Shortcomings in the current literature are identified and future direction to enhance research efforts within the field of CF-related dysmotility is provided. Conclusions: The influence of CF on GI integrity and motility is far-reaching. Despite improvements in longevity and advancement of pulmonary-specific treatment strategies, further high-quality research targeting the evaluation and management of GI dysmotility in pwCF is needed.

Colonic Resection in an 8-Year-Old Girl with Intractable Functional Constipation and Diffuse Colonic Dysmotility and Failed Antegrade Flushes.

Optimal surgical management of patients with intractable constipation and diffuse colonic motility is not well defined. We present a patient with such a history, who ultimately achieved successful surgical management of constipation through a stepwise approach. An 8-year-old female presents with longstanding constipation and diffuse colonic dysmotility demonstrated with colonic manometry. She initially underwent sigmoid resection and cecostomy which failed and required diverting ileostomy. We initially proceeded with an extended resection, colonic derotation (Deloyers procedure), and neo-appendicostomy (neo-Malone) which resulted in successful spontaneous stooling for 1 year. Her constipation recurred and she subsequently underwent completion colectomy with ileorectal anastomosis given that she previously demonstrated ability to stool independently. Six months from surgery the patient continues to stool daily with assistance of fiber and loperamide. This case highlights a stepwise surgical approach to managing constipation due to diffuse colonic dysmotility and demonstrates that diffuse dysmotility may benefit from an upfront subtotal resection; however, it is crucial to assess a patient's ability to empty their rectum prior.

Esophagogastric Junction Outflow Obstruction: A Diagnosis in Evolution.

Esophagogastric junction outflow obstruction (EGJOO) is a rapidly evolving diagnosis that can represent early or variant achalasia. Since the publication of the Chicago Classification version 4.0, the criteria for this diagnosis have been more stringent. Currently, the criteria include an elevated median integrated relaxation pressure (IRP) in both the supine and upright positions, elevated intrabolus pressure in at least 20% of supine swallows, dysphagia and/or chest pain, as well as an abnormal timed barium esophagram and/or impedance planimetry testing. Additionally, other secondary causes may result in an elevated IRP and must be excluded. The management of conclusive EGJOO is targeted therapy to the lower esophageal sphincter (LES), although treatment is not straightforward. Overall, adjuvant testing and data should be scrutinized for appropriateness of LES disruption. The spectrum of treatment options includes simple monitoring as well as more invasive therapies such as endoscopic dilation and myotomy. This article explores the newest criteria and management options for clinically relevant EGJOO.

Isolated AL Amyloidosis of the Colon: A Rare Presentation.

Amyloidosis is a group of rare deposition diseases marked by the accumulation of abnormal fibrillar proteins in the extracellular space of various tissues. In both AL and AA amyloidosis, the most common variants, isolated involvement to any one organ is uncommon and involvement to the colon alone is especially rare. We present the case of a patient who was initially found to have AL amyloidosis on prior screening colonoscopy that was reconfirmed several years with repeat evaluation for chronic constipation. This disease process is often insidious and can be overlooked by providers given the lack of overwhelming symptoms.

Sustained Effectiveness and Safety of Therapeutic miR-10a/b in Alleviating Diabetes and Gastrointestinal Dysmotility without Inducing Cancer or Inflammation in Murine Liver and Colon.

microRNAs (miRNAs) are key regulators of both physiological and pathophysiological mechanisms in diabetes and gastrointestinal (GI) dysmotility. Our previous studies have demonstrated the therapeutic potential of miR-10a-5p mimic and miR-10b-5p mimic (miR-10a/b mimics) in rescuing diabetes and GI dysmotility in murine models of diabetes. In this study, we elucidated the safety profile of a long-term treatment with miR-10a/b mimics in diabetic mice. Male C57BL/6 mice were fed a high-fat, high-sucrose diet (HFHSD) to induce diabetes and treated by five subcutaneous injections of miR-10a/b mimics for a 5 month period. We examined the long-term effects of the miRNA mimics on diabetes and GI dysmotility, including an assessment of potential risks for cancer and inflammation in the liver and colon using biomarkers. HFHSD-induced diabetic mice subcutaneously injected with miR-10a/b mimics on a monthly basis for 5 consecutive months exhibited a marked reduction in fasting blood glucose levels with restoration of insulin and significant weight loss, improved glucose and insulin intolerance, and restored GI transit time. In addition, the miR-10a/b mimic-treated diabetic mice showed no indication of risk for cancer development or inflammation induction in the liver, colon, and blood for 5 months post-injections. This longitudinal study demonstrates that miR-10a/b mimics, when subcutaneously administered in diabetic mice, effectively alleviate diabetes and GI dysmotility for 5 months with no discernible risk for cancer or inflammation in the liver and colon. The sustained efficacy and favorable safety profiles position miR-10a/b mimics as promising candidates in miRNA-based therapeutics for diabetes and GI dysmotility.

Novel CHRNA3 variants identified in a patient with bladder dysfunction, dysautonomia, and gastrointestinal dysmotility.

Congenital anomalies of the kidney and urinary tract (CAKUT) are estimated to be responsible for 20%-50% of congenital anomalies and are also a leading etiology of early-onset renal disease. Primary CAKUT are caused by genetic factors that impair proper in-utero genitourinary tract development and secondary CAKUT result from the influence of environmental factors. The CHRNA3 gene, which encodes the Alpha-3 subunit of the nicotinic acetylcholine receptor, is hypothesized to be associated with Megacystis-microcolon-intestinal hyperperistalsis syndrome. More recently, pathogenic variants in CHRNA3 have been identified in individuals with CAKUT as well as individuals with panautonomic failure. Here we present a patient with neurogenic bladder, vesicoureteral reflux, mydriasis, and gastrointestinal dysmotility found to have novel compound heterozygous variants in CHRNA3. These findings support the consideration of CHRNA3 disruption in the differential for CAKUT with dysautonomia and gastrointestinal dysmotility.

Gastrointestinal Hemorrhage and Diffuse Bowel Dilation in Huntington Disease.

Huntington disease (HD) is a neurodegenerative condition associated with pathologic involvement beyond the striatum including involvement of the autonomic nervous system. Bowel dysfunction is found in patients with HD, but the exact mechanism is poorly understood and not well reported. Patients may be affected with problems such as dysphagia, weight loss, nutritional deficiencies, esophagitis, and gastritis. Lower bowel symptoms are more prevalent with longer disease course. We present a case of a patient with late-stage HD who presents with severe esophagitis causing gastrointestinal hemorrhage, significant dysmotility including chronic dysphagia requiring gastrostomy tube, and chronic small bowel and colonic ileus.

Idiopathic Slow Transit Constipation: Pathophysiology, Diagnosis, and Management.

Slow transit constipation (STC) has an estimated prevalence of 2-4% of the general population, and although it is the least prevalent of the chronic constipation phenotypes, it more commonly causes refractory symptoms and is associated with significant psychosocial stress, poor quality of life, and high healthcare costs. This review provides an overview of the pathophysiology, diagnosis, and management options in STC. STC occurs due to colonic dysmotility and is thought to be a neuromuscular disorder of the colon. Several pathophysiologic features have been observed in STC, including reduced contractions on manometry, delayed emptying on transit studies, reduced numbers of interstitial cells of Cajal on histology, and reduced amounts of excitatory neurotransmitters within myenteric plexuses. The underlying aetiology is uncertain, but autoimmune and hormonal mechanisms have been hypothesised. Diagnosing STC may be challenging, and there is substantial overlap with the other clinical constipation phenotypes. Prior to making a diagnosis of STC, other primary constipation phenotypes and secondary causes of constipation need to be ruled out. An assessment of colonic transit time is required for the diagnosis and can be performed by a number of different methods. There are several different management options for constipation, including lifestyle, dietary, pharmacologic, interventional, and surgical. The effectiveness of the available therapies in STC differs from that of the other constipation phenotypes, and prokinetics often make up the mainstay for those who fail standard laxatives. There are few available management options for patients with medically refractory STC, but patients may respond well to surgical intervention. STC is a common condition associated with a significant burden of disease. It can present a clinical challenge, but a structured approach to the diagnosis and management can be of great value to the clinician. There are many therapeutic options available, with some having more benefits than others.