Expression and function of transient receptor potential melastatin 3 in the spinal afferent innervation of the mouse colon.

Abdominal pain is a cardinal symptom of inflammatory bowel disease (IBD). Transient receptor potential (TRP) channels contribute to abdominal pain in preclinical models of IBD, and TRP melastatin 3 (TRPM3) has recently been implicated in inflammatory bladder and joint pain in rodents. We hypothesized that TRPM3 is involved in colonic sensation and is sensitized during colitis. We used immunohistochemistry, ratiometric Ca2+ imaging, and colonic afferent nerve recordings in mice to evaluate TRPM3 protein expression in colon-projecting dorsal root ganglion (DRG) neurons, as well as functional activity in DRG neurons and colonic afferent nerves. Colitis was induced using dextran sulfate sodium (DSS) in drinking water. TRPM3 protein expression was observed in 76% of colon-projecting DRG neurons and was often colocalized with calcitonin gene-related peptide. The magnitudes of intracellular Ca2+ transients in DRG neurons in response to the TRPM3 agonists CIM-0216 and pregnenolone sulfate sodium were significantly greater in neurons from mice with colitis compared with controls. In addition, the percentage of DRG neurons from mice with colitis that responded to CIM-0216 was significantly increased. CIM-0216 also increased the firing rate of colonic afferent nerves from control and mice with colitis. The TRPM3 inhibitor isosakuranetin inhibited the mechanosensitive response to distension of wide dynamic range afferent nerve units from mice with colitis but had no effect in control mice. Thus, TRPM3 contributes to colonic sensory transduction and may be a potential target for treating pain in IBD.NEW & NOTEWORTHY This is the first study to characterize TRPM3 protein expression and function in colon-projecting DRG neurons. A TRPM3 agonist excited DRG neurons and colonic afferent nerves from healthy mice. TRPM3 agonist responses in DRG neurons were elevated during colitis. Inhibiting TRPM3 reduced the firing of wide dynamic range afferent nerves from mice with colitis but had no effect in control mice.

Changes in signalling from faecal neuroactive metabolites following dietary modulation of IBS pain.

OBJECTIVE: Dietary therapies for irritable bowel syndrome (IBS) have received increasing interest but predicting which patients will benefit remains a challenge due to a lack of mechanistic insight. We recently found evidence of a role for the microbiota in dietary modulation of pain signalling in a humanised mouse model of IBS. This randomised cross-over study aimed to test the hypothesis that pain relief following reduced consumption of fermentable carbohydrates is the result of changes in luminal neuroactive metabolites. DESIGN: IBS (Rome IV) participants underwent four trial periods: two non-intervention periods, followed by a diet low (LFD) and high in fermentable carbohydrates for 3 weeks each. At the end of each period, participants completed questionnaires and provided stool. The effects of faecal supernatants (FS) collected before (IBS FS) and after a LFD (LFD FS) on nociceptive afferent neurons were assessed in mice using patch-clamp and ex vivo colonic afferent nerve recording techniques. RESULTS: Total IBS symptom severity score and abdominal pain were reduced by the LFD (N=25; p<0.01). Excitability of neurons was increased in response to IBS FS, but this effect was reduced (p<0.01) with LFD FS from pain-responders. IBS FS from pain-responders increased mechanosensitivity of nociceptive afferent nerve axons (p<0.001), an effect lost following LFD FS administration (p=NS) or when IBS FS was administered in the presence of antagonists of histamine receptors or protease inhibitors. CONCLUSIONS: In a subset of IBS patients with improvement in abdominal pain following a LFD, there is a decrease in pronociceptive signalling from FS, suggesting that changes in luminal mediators may contribute to symptom response.

Prevalence and Characteristics of Avoidant/Restrictive Food Intake Disorder in Pediatric Neurogastroenterology Patients.

ABSTRACT: Recent reports document avoidant/restrictive food intake disorder (ARFID) symptoms among 13-40% of adults presenting to neurogastroenterology clinics, but ARFID in pediatrics is understudied. We conducted a retrospective review of charts from 129 consecutive referrals (ages 6-18 years; 57% female) for pediatric neurogastroenterology examination, from January 2016 through December 2018. Eleven cases (8%) met the full criteria for ARFID by the Diagnostic and Statistical Manual of Mental Disorders, 5th edition and 19 cases (15%) had clinically significant avoidant/ restrictive eating behaviors with insufficient information for a definitive ARFID diagnosis. Of patients with ARFID symptoms (n = 30), 20 (67%) cited fear of gastrointestinal symptoms as motivation for their avoidant/ restrictive eating. Compared to patients without ARFID symptoms, patients with ARFID symptoms were older (P  < .001), more likely to be female (51% vs 79%, P  = 0.014), and more frequently presented with eating/weight-related complaints (15% vs 33%, P  = 0.026). This pilot retrospective study showed ARFID symptoms present in 23% of pediatric neurogastroenterology patients; further research is needed to understand risk and maintenance factors of ARFID in the neurogastroenterology setting.

Designing a Framework for Remote Cancer Care Through Community Co-design: Participatory Development Study.

BACKGROUND: Recent shifts to telemedicine and remote patient monitoring demonstrate the potential for new technology to transform health systems; yet, methods to design for inclusion and resilience are lacking. OBJECTIVE: The aim of this study is to design and implement a participatory framework to produce effective health care solutions through co-design with diverse stakeholders. METHODS: We developed a design framework to cocreate solutions to locally prioritized health and communication problems focused on cancer care. The framework is premised on the framing and discovery of problems through community engagement and lead-user innovation with the hypothesis that diversity and inclusion in the co-design process generate more innovative and resilient solutions. Discovery, design, and development were implemented through structured phases with design studios at various locations in urban and rural Kentucky, including Appalachia, each building from prior work. In the final design studio, working prototypes were developed and tested. Outputs were assessed using the System Usability Scale as well as semistructured user feedback. RESULTS: We co-designed, developed, and tested a mobile app (myPath) and service model for distress surveillance and cancer care coordination following the LAUNCH (Linking and Amplifying User-Centered Networks through Connected Health) framework. The problem of awareness, navigation, and communication through cancer care was selected by the community after framing areas for opportunity based on significant geographic disparities in cancer and health burden resource and broadband access. The codeveloped digital myPath app showed the highest perceived combined usability (mean 81.9, SD 15.2) compared with the current gold standard of distress management for patients with cancer, the paper-based National Comprehensive Cancer Network Distress Thermometer (mean 74.2, SD 15.8). Testing of the System Usability Scale subscales showed that the myPath app had significantly better usability than the paper Distress Thermometer (t63=2.611; P=.01), whereas learnability did not differ between the instruments (t63=-0.311; P=.76). Notable differences by patient and provider scoring and feedback were found. CONCLUSIONS: Participatory problem definition and community-based co-design, design-with methods, may produce more acceptable and effective solutions than traditional design-for approaches.

Deoxycholic acid activates colonic afferent nerves via 5-HT3 receptor-dependent and -independent mechanisms.

Increased bile acids in the colon can evoke increased epithelial secretion resulting in diarrhea, but little is known about whether colonic bile acids contribute to abdominal pain. This study aimed to investigate the mechanisms underlying activation of colonic extrinsic afferent nerves and their neuronal cell bodies by a major secondary bile acid, deoxycholic acid (DCA). All experiments were performed on male C57BL/6 mice. Afferent sensitivity was evaluated using in vitro extracellular recordings from mesenteric nerves in the proximal colon (innervated by vagal and spinal afferents) and distal colon (spinal afferents only). Neuronal excitability of cultured dorsal root ganglion (DRG) and nodose ganglion (NG) neurons was examined with perforated patch clamp. Colonic 5-HT release was assessed using ELISA, and 5-HT immunoreactive enterochromaffin (EC) cells were quantified. Intraluminal DCA increased afferent nerve firing rate concentration dependently in both proximal and distal colon. This DCA-elicited increase was significantly inhibited by a 5-HT3 antagonist in the proximal colon but not in the distal colon, which may be in part due to lower 5-HT immunoreactive EC cell density and lower 5-HT levels in the distal colon following DCA stimulation. DCA increased the excitability of DRG neurons, whereas it decreased the excitability of NG neurons. DCA potentiated mechanosensitivity of high-threshold spinal afferents independent of 5-HT release. Together, this study suggests that DCA can excite colonic afferents via direct and indirect mechanisms but the predominant mechanism may differ between vagal and spinal afferents. Furthermore, DCA increased mechanosensitivity of high-threshold spinal afferents and may be a mechanism of visceral hypersensitivity.NEW & NOTEWORTHY Deoxycholic acid (DCA) directly excites spinal afferents and, to a lesser extent, indirectly via mucosal 5-HT release. DCA potentiates mechanosensitivity of high-threshold spinal afferents independent of 5-HT release. DCA increases vagal afferent firing in proximal colon via 5-HT release but directly inhibits the excitability of their cell bodies.

Protease-Mediated Suppression of DRG Neuron Excitability by Commensal Bacteria.

Peripheral pain signaling reflects a balance of pronociceptive and antinociceptive influences; the contribution by the gastrointestinal microbiota to this balance has received little attention. Disorders, such as inflammatory bowel disease and irritable bowel syndrome, are associated with exaggerated visceral nociceptive actions that may involve altered microbial signaling, particularly given the evidence for bacterial dysbiosis. Thus, we tested whether a community of commensal gastrointestinal bacteria derived from a healthy human donor (microbial ecosystem therapeutics; MET-1) can affect the excitability of male mouse DRG neurons. MET-1 reduced the excitability of DRG neurons by significantly increasing rheobase, decreasing responses to capsaicin (2 µm) and reducing action potential discharge from colonic afferent nerves. The increase in rheobase was accompanied by an increase in the amplitude of voltage-gated K+ currents. A mixture of bacterial protease inhibitors abrogated the effect of MET-1 effects on DRG neuron rheobase. A serine protease inhibitor but not inhibitors of cysteine proteases, acid proteases, metalloproteases, or aminopeptidases abolished the effects of MET-1. The serine protease cathepsin G recapitulated the effects of MET-1 on DRG neurons. Inhibition of protease-activated receptor-4 (PAR-4), but not PAR-2, blocked the effects of MET-1. Furthermore, Faecalibacterium prausnitzii recapitulated the effects of MET-1 on excitability of DRG neurons. We conclude that serine proteases derived from commensal bacteria can directly impact the excitability of DRG neurons, through PAR-4 activation. The ability of microbiota-neuronal interactions to modulate afferent signaling suggests that therapies that induce or correct microbial dysbiosis may impact visceral pain.SIGNIFICANCE STATEMENT Commercially available probiotics have the potential to modify visceral pain. Here we show that secretory products from gastrointestinal microbiota derived from a human donor signal to DRG neurons. Their secretory products contain serine proteases that suppress excitability via activation of protease-activated receptor-4. Moreover, from this community of commensal microbes, Faecalibacterium prausnitzii strain 16-6-I 40 fastidious anaerobe agar had the greatest effect. Our study suggests that therapies that induce or correct microbial dysbiosis may affect the excitability of primary afferent neurons, many of which are nociceptive. Furthermore, identification of the bacterial strains capable of suppressing sensory neuron excitability, and their mechanisms of action, may allow therapeutic relief for patients with gastrointestinal diseases associated with pain.

Protease-Induced Excitation of Dorsal Root Ganglion Neurons in Response to Acute Perturbation of the Gut Microbiota Is Associated With Visceral and Somatic Hypersensitivity.

BACKGROUND & AIMS: Abdominal pain is a major symptom of diseases that are associated with microbial dysbiosis, including irritable bowel syndrome and inflammatory bowel disease. Germ-free mice are more prone to abdominal pain than conventionally housed mice, and reconstitution of the microbiota in germ-free mice reduces abdominal pain sensitivity. However, the mechanisms underlying microbial modulation of pain remain elusive. We hypothesized that disruption of the intestinal microbiota modulates the excitability of peripheral nociceptive neurons. METHODS: In vivo and in vitro assays of visceral sensation were performed on mice treated with the nonabsorbable antibiotic vancomycin (50 µg/mL in drinking water) for 7 days and water-treated control mice. Bacterial dysbiosis was verified by 16s rRNA analysis of stool microbial composition. RESULTS: Treatment of mice with vancomycin led to an increased sensitivity to colonic distension in vivo and in vitro and hyperexcitability of dorsal root ganglion (DRG) neurons in vitro, compared with controls. Interestingly, hyperexcitability of DRG neurons was not restricted to those that innervated the gut, suggesting a widespread effect of gut dysbiosis on peripheral pain circuits. Consistent with this, mice treated with vancomycin were more sensitive than control mice to thermal stimuli applied to hind paws. Incubation of DRG neurons from naive mice in serum from vancomycin-treated mice increased DRG neuron excitability, suggesting that microbial dysbiosis alters circulating mediators that influence nociception. The cysteine protease inhibitor E64 (30 nmol/L) and the protease-activated receptor 2 (PAR-2) antagonist GB-83 (10 µmol/L) each blocked the increase in DRG neuron excitability in response to serum from vancomycin-treated mice, as did the knockout of PAR-2 in NaV1.8-expressing neurons. Stool supernatant, but not colonic supernatant, from mice treated with vancomycin increased DRG neuron excitability via cysteine protease activation of PAR-2. CONCLUSIONS: Together, these data suggest that gut microbial dysbiosis alters pain sensitivity and identify cysteine proteases as a potential mediator of this effect.

Reduced endoglin activity limits cardiac fibrosis and improves survival in heart failure.

BACKGROUND: Heart failure is a major cause of morbidity and mortality worldwide. The ubiquitously expressed cytokine transforming growth factor-ß1 (TGFß1) promotes cardiac fibrosis, an important component of progressive heart failure. Membrane-associated endoglin is a coreceptor for TGFß1 signaling and has been studied in vascular remodeling and preeclampsia. We hypothesized that reduced endoglin expression may limit cardiac fibrosis in heart failure. METHODS AND RESULTS: We first report that endoglin expression is increased in the left ventricle of human subjects with heart failure and determined that endoglin is required for TGFß1 signaling in human cardiac fibroblasts using neutralizing antibodies and an siRNA approach. We further identified that reduced endoglin expression attenuates cardiac fibrosis, preserves left ventricular function, and improves survival in a mouse model of pressure-overload-induced heart failure. Prior studies have shown that the extracellular domain of endoglin can be cleaved and released into the circulation as soluble endoglin, which disrupts TGFß1 signaling in endothelium. We now demonstrate that soluble endoglin limits TGFß1 signaling and type I collagen synthesis in cardiac fibroblasts and further show that soluble endoglin treatment attenuates cardiac fibrosis in an in vivo model of heart failure. CONCLUSION: Our results identify endoglin as a critical component of TGFß1 signaling in the cardiac fibroblast and show that targeting endoglin attenuates cardiac fibrosis, thereby providing a potentially novel therapeutic approach for individuals with heart failure.

Upper Esophageal Sphincter Dysfunction in Children with Type 1 Laryngeal Cleft after Failed Primary Cleft Repair.

Changes in pharyngeal and upper-esophageal-sphincter (UES) motor dynamics contribute to swallowing dysfunction. Children with type 1 laryngeal clefts can present with swallowing dysfunction and associated symptoms which may persist even after the initial endoscopic intervention. This study sought to characterize pharyngeal and esophageal motor function in children with type 1 laryngeal clefts who had persistent presenting symptoms after their initial therapeutic intervention. We retrospectively analyzed high-resolution esophageal manometry studies of children ≤ 18 years old with type 1 laryngeal clefts who had an esophageal manometry study performed for persistent symptoms after an initial repair. A total of 16 children were found to have significantly increased UES resting pressure, UES pre- and post-swallow maximum pressures, and duration of UES contraction during swallows in comparison to nine age-matched controls of children without pharyngeal anatomical abnormalities. There was no difference between UES residual pressures or pharyngeal dynamics between the two groups. UES resting and residual pressures did not correlate with VFFS in penetration and aspiration scores of children with type 1 laryngeal clefts status post repair. Our study is the first to identify specific changes in UES motor function in patients with type 1 laryngeal cleft post initial repair.

Elevated soluble fms-like tyrosine kinase-1 levels in acute coronary occlusion.

OBJECTIVE: Early recognition of an acute coronary occlusion (ACO) improves clinical outcomes. Soluble fms-like tyrosine kinase-1 (sFLT1) is an endothelium-derived protein induced by hypoxia. We tested whether sFLT1 levels are elevated in ACO. METHODS AND RESULTS: Serum sFLT1 levels were measured by enzyme-linked immunosorbent assay in patients with ST-segment elevations and angiographically confirmed ACO, unstable angina/non ST-segment elevation myocardial infarction, and 2 control groups. To further explore sFLT1 release, a mouse model of ACO and in vitro human coronary artery endothelial cell injury were used. sFLT1 levels were increased in ACO compared with unstable angina/non-ST-elevation myocardial infarction, catheterized controls, or healthy volunteers (200.7±15.5 versus 70.7±44.0 versus 10.2±4.0 versus 11.7±1.7 pg/mL respectively, P<0.001 versus ACO). At presentation, all ACO patients had elevated sFLT1 levels (>15 pg/mL, 99th percentile in controls), whereas 57% had levels of the MB isoform of creatine kinase levels >10 ng/mL (P<0.01) and 85% had ultrasensitive troponin I levels >0.05 ng/mL (P<0.05). Within 60 minutes after symptom onset, sFLT1 was more sensitive than the MB isoform of creatine kinase or ultrasensitive troponin I for ACO (100% versus 20% versus 20% respectively; P≤0.01 for each). Within 60 minutes of ACO in mice, sFLT1 levels were elevated. Hypoxia and thrombin increased sFLT1 levels within 15 minutes in human coronary artery endothelial cells. CONCLUSIONS: sFLT1 levels may be an early indicator of endothelial hypoxia in ACO.

Estrogen attenuates left ventricular and cardiomyocyte hypertrophy by an estrogen receptor-dependent pathway that increases calcineurin degradation.

Left ventricular (LV) hypertrophy commonly develops in response to chronic hypertension and is a significant risk factor for heart failure and death. The serine-threonine phosphatase calcineurin (Cn)A plays a critical role in the development of pathological hypertrophy. Previous experimental studies in murine models show that estrogen limits pressure overload-induced hypertrophy; our purpose was to explore further the mechanisms underlying this estrogen effect. Wild-type, ovariectomized female mice were treated with placebo or 17beta-estradiol (E2), followed by transverse aortic constriction (TAC), to induce pressure overload. At 2 weeks, mice underwent physiological evaluation, immediate tissue harvest, or dispersion of cardiomyocytes. E2 replacement limited TAC-induced LV and cardiomyocyte hypertrophy while attenuating deterioration in LV systolic function and contractility. These E2 effects were associated with reduced abundance of CnA. The primary downstream targets of CnA are the nuclear factor of activated T-cell (NFAT) family of transcription factors. In transgenic mice expressing a NFAT-activated promoter/luciferase reporter gene, E2 limited TAC-induced activation of NFAT. Moreover, the inhibitory effects of E2 on LV hypertrophy were absent in CnA knockout mice, supporting the notion that CnA is an important target of E2-mediated inhibition. In cultured rat cardiac myocytes, E2 inhibited agonist-induced hypertrophy while also decreasing CnA abundance and NFAT activation. Agonist stimulation also reduced CnA ubiquitination and degradation that was prevented by E2; all in vitro effects of estrogen were reversed by an estrogen receptor (ER) antagonist. These data support that E2 reduces pressure overload induced hypertrophy by an ER-dependent mechanism that increases CnA degradation, unveiling a novel mechanism by which E2 and ERs regulate pathological LV and cardiomyocyte growth.

Pan-enteric neuropathy and dysmotility are present in a mouse model of short-segment Hirschsprung disease and may contribute to post-pullthrough morbidity.

PURPOSE: Hirschsprung disease (HSCR) is characterized by distal intestinal aganglionosis. While surgery is lifesaving, gastrointestinal (GI) motility disorders persist in many patients. Our objective was to determine whether enteric nervous system (ENS) abnormalities exist in the ganglionated portions of the GI tract far proximal to the aganglionic region and whether these are associated with GI dysmotility. METHODS: Using Ednrb-null mice, a model of HSCR, immunohistochemical analysis was performed to evaluate quantitatively ENS structure in proximal colon, small intestine, and stomach. Gastric emptying and intestinal transit were measured in vivo and small and large bowel contractility was assessed by spatiotemporal mapping ex vivo. RESULTS: Proximal colon of HSCR mice had smaller ganglia and decreased neuronal fiber density, along with a marked reduction in migrating motor complexes. The distal small intestine exhibited significantly fewer ganglia and decreased neuronal fiber density, and this was associated with delayed small intestinal transit time. Finally, in the stomach of HSCR mice, enteric neuronal packing density was increased and gastric emptying was faster. CONCLUSIONS: ENS abnormalities and motility defects are present throughout the ganglionated portions of the GI tract in Ednrb-deficient mice. This may explain the GI morbidity that often occurs following pull-through surgery for HSCR.

Modified external approach to the pediatric cricopharyngeal myotomy: A case series.

OBJECTIVE: To assess the success of a modified approach to external pediatric cricopharyngeal myotomy in children with inappropriate upper esophageal sphincter relaxation as determined by video fluoroscopic swallow study (VFSS) and pediatric manometry findings. METHODS: This is a case series in which hospital records of all patients who underwent a modified external approach to pediatric cricopharyngeal myotomy 2017 to 2019 were reviewed at a single institution. The primary outcome measure was post-operative diet and presence of aspiration/penetration on post-operative VFSS. RESULTS: A total of 7 patients underwent modified external approach to pediatric cricopharyngeal myotomy. The average age of the child at the time of surgery was 5.6 (±3.7) years. The average duration (SD) of surgery was 90 (±30) minutes and no complications were observed. 6 of 7 patients (86%) demonstrated an improvement in swallow function after the procedure. The single child who did not was suffering from a posterior fossa tumor which was resected and radiated, which likely made their dysphagia multi-factorial. Although no pediatric normative data exists for upper esophageal sphincter pressure, we observed an average decrease in UES residual pressure of 8.5 (±15.1) mmHg and an average decrease in mean UES pressure of 21.2 (±35.1) mmHg. CONCLUSIONS: The modified external approach to the pediatric cricopharyngeal myotomy appears to be a safe and efficient procedure with no apparent complications to date. However, further longitudinal data is needed to formally evaluate the efficacy of this procedure when treating pediatric cricopharyngeal achalasia.

Hypoganglionosis in the gastric antrum causes delayed gastric emptying.

BACKGROUND: Enteric nervous system (ENS) abnormalities have been implicated in delayed gastric emptying but studies exploring potential treatment options are limited by the lack of an experimental animal model. We examined the ENS abnormalities in the mouse stomach associated with aging, developed a novel model of gastroparesis, and established a new approach to measure gastric emptying. METHODS: A modified gastric emptying assay was developed, validated in nNOS -/- mice, and tested in mice at multiple ages. Age-related changes in ENS structure were analyzed by immunohistochemistry. Gastric aganglionosis was generated in Wnt1-iDTR mice using focal administration of diphtheria toxin (DT) into the anterior antral wall. KEY RESULTS: Older mice (>5 months) exhibit hypoganglionosis in the gastric antrum and a decreased proportion of nNOS neurons as compared to younger mice (age 5-7 weeks). This was associated with a significant age-dependent decrease in liquid and solid gastric emptying. A novel model of gastric antrum hypoganglionosis was established using neural crest-specific expression of diphtheria toxin receptor. In this model, a significant reduction in liquid and solid gastric emptying is observed. CONCLUSIONS & INFERENCES: Older mice exhibit delayed gastric emptying associated with hypoganglionosis and a reduction in nNOS-expressing neurons in the antrum. The causal relationship between antral hypoganglionosis and delayed gastric emptying was verified using a novel experimental model of ENS ablation. This study provides new information regarding the pathogenesis of delayed gastric emptying and provides a robust model system to study this disease and develop novel treatments.

Barn-Raising on the Digital Frontier: The L.A.U.N.C.H. Collaborative.

A meta-analysis of oncology papers from around the world revealed that cancer patients who lived more than 50 miles away from hospital centers routinely presented with more advanced stages of disease at diagnosis, exhibited lower adherence to prescribed treatments, presented with poorer diagnoses, and reported a lower quality of life than patients who lived nearer to care facilities. Connected health approaches-or the use of broadband and telecommunications technologies to evaluate, diagnose, and monitor patients beyond the clinic-are becoming an indispensable tool in medicine to overcome the obstacle of distance.

Enteric neuronal cell therapy reverses architectural changes in a novel diphtheria toxin-mediated model of colonic aganglionosis.

Hirschsprung disease (HSCR) is characterized by absence of the enteric nervous system (ENS) in the distal bowel. Despite removal of the aganglionic segment, gastrointestinal (GI) problems persist. Cell therapy offers potential treatment but use of genetic models is limited by their poor survival. We have developed a novel model of aganglionosis in which enteric neural crest-derived cells (ENCDCs) express diphtheria toxin (DT) receptor. Local DT injection into the colon wall results in focal, specific, and sustained ENS ablation without altering GI transit or colonic contractility, allowing improved survival over other aganglionosis models. Focal ENS ablation leads to increased smooth muscle and mucosal thickness, and localized inflammation. Transplantation of ENCDCs into this region leads to engraftment, migration, and differentiation of enteric neurons and glial cells, with restoration of normal architecture of the colonic epithelium and muscle, reduction in inflammation, and improved survival.