The long Filamin-A isoform is required for intestinal development and motility: implications for chronic intestinal pseudo-obstruction.

Filamin A (FLNA) is a cytoplasmic actin binding protein, recently shown to be expressed as a long and short isoform. Mutations in FLNA are associated with a wide spectrum of disorders, including an X-linked form of chronic intestinal pseudo-obstruction (CIPO). However, the role of FLNA in intestinal development and function is largely unknown. In this study, we show that FLNA is expressed in the muscle layer of the small intestine from early human fetal stages. Expression of FLNA variants associated with CIPO, blocked expression of the long flna isoform and led to an overall reduction of RNA and protein levels. As a consequence, contractility of human intestinal smooth muscle cells was affected. Lastly, our transgenic zebrafish line showed that the flna long isoform is required for intestinal elongation and peristalsis. Histological analysis revealed structural and architectural changes in the intestinal smooth muscle of homozygous fish, likely triggered by the abnormal expression of intestinal smooth muscle markers. No defect in the localization or numbers of enteric neurons was observed. Taken together, our study demonstrates that the long FLNA isoform contributes to intestinal development and function. Since loss of the long FLNA isoform does not seem to affect the enteric nervous system, it likely results in a myopathic form of CIPO, bringing new insights to disease pathogenesis.

Lysosomal dysfunction and overload of nucleosides in thymidine phosphorylase deficiency of MNGIE.

Inherited deficiency of thymidine phosphorylase (TP), encoded by TYMP, leads to a rare disease with multiple mitochondrial DNA (mtDNA) abnormalities, mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). However, the impact of TP deficiency on lysosomes remains unclear, which are important for mitochondrial quality control and nucleic acid metabolism. Muscle biopsy tissue and skin fibroblasts from MNGIE patients, patients with m.3243 A > G mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and healthy controls (HC) were collected to perform mitochondrial and lysosomal functional analyses. In addition to mtDNA abnormalities, compared to controls distinctively reduced expression of LAMP1 and increased mitochondrial content were detected in the muscle tissue of MNGIE patients. Skin fibroblasts from MNGIE patients showed decreased expression of LAMP2, lowered lysosomal acidity, reduced enzyme activity and impaired protein degradation ability. TYMP knockout or TP inhibition in cells can also induce the similar lysosomal dysfunction. Using lysosome immunoprecipitation (Lyso- IP), increased mitochondrial proteins, decreased vesicular proteins and V-ATPase enzymes, and accumulation of various nucleosides were detected in lysosomes with TP deficiency. Treatment of cells with high concentrations of dThd and dUrd also triggers lysosomal dysfunction and disruption of mitochondrial homeostasis. Therefore, the results provided evidence that TP deficiency leads to nucleoside accumulation in lysosomes and lysosomal dysfunction, revealing the widespread disruption of organelles underlying MNGIE.

Local association of Trypanosoma cruzi chronic infection foci and enteric neuropathic lesions at the tissue micro-domain scale.

Digestive Chagas disease (DCD) is an enteric neuropathy caused by Trypanosoma cruzi infection. The mechanism of pathogenesis is poorly understood and the lack of a robust, predictive animal model has held back research. We screened a series of mouse models using gastrointestinal tracer assays and in vivo infection imaging systems to discover a subset exhibiting chronic digestive transit dysfunction and significant retention of faeces in both sated and fasted conditions. The colon was a specific site of both tissue parasite persistence, delayed transit and dramatic loss of myenteric neurons as revealed by whole-mount immunofluorescence analysis. DCD mice therefore recapitulated key clinical manifestations of human disease. We also exploited dual reporter transgenic parasites to home in on locations of rare chronic infection foci in the colon by ex vivo bioluminescence imaging and then used fluorescence imaging in tissue microdomains to reveal co-localisation of infection and enteric nervous system lesions. This indicates that long-term T. cruzi-host interactions in the colon drive DCD pathogenesis, suggesting that the efficacy of anti-parasitic chemotherapy against chronic disease progression warrants further pre-clinical investigation.

Loss-of-function variants within LMOD1 actin-binding site 2 cause pediatric intestinal pseudo-obstruction by impairing protein stability and actin nucleation.

The leiomodin1 (LMOD1) gene, encoding a potent actin nucleator, was recently reported as a potential pathogenic gene of megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS, OMIM 619362). However, only a single patient has been reported to have LMOD1 mutations, and the underlying pathogenic mechanism remains unknown. Here, we described a male infant with LMOD1 mutations presenting typical symptoms of pediatric intestinal pseudo-obstruction (PIPO) but without megacystis and microcolon. Two compound heterozygous missense variants (c.1106C>T, p.T369M; c.1262G>A, p.R421H) were identified, both affecting highly conserved amino acid residues within the second actin-binding site (ABS2) domain of LMOD1. Expression analysis showed that both variants resulted in significantly reduced protein amounts, especially for p.T369M, which was almost undetectable. The reduction was only partially rescued by the proteasome inhibitor MG-132, indicating that there might be proteasome-independent pathways involved in the degradation of the mutant proteins. Molecular modeling showed that variant p.T369M impaired the local protein conformation of the ABS2 domain, while variant p.R421H directly impaired the intermolecular interaction between ABS2 and actin. Accordingly, both variants significantly damaged LMOD1-mediated actin nucleation. These findings provide further human genetic evidence supporting LMOD1 as a pathogenic gene underlying visceral myopathy including PIPO and MMIHS, strengthen the critical role of ABS2 domain in LMOD1-mediated actin nucleation, and moreover, reveal an unrecognized role of ABS2 in protein stability.

Intestinal Pathology in Patients With Pathogenic ACTG2-Variant Visceral Myopathy: 16 Patients From 12 Families and Review of the Literature.

BACKGROUND: Dominant gamma-smooth muscle actin gene (ACTG2) variants cause clinically diverse forms of visceral myopathy. Many patients undergo intestinal resection or biopsy before identification of their genetic defect. The pathology of ACTG2-variant visceral myopathy has not been evaluated systematically. METHODS: Glass slides, ultrastructural images, molecular genetic reports, and clinical records from 16 patients with pathogenic (15) or likely pathogenic (1) ACTG2 variants were reviewed and compared with surgical specimens from controls (no evidence of a primary myopathy or pseudo-obstruction due to Hirschsprung disease) and published descriptions. RESULTS: The variable clinical manifestations in our cohort matched those in the literature. Only non-specific light and electron microscopic findings observed in non-myopathic controls were encountered in 13 of 16 patients. The remaining 3 patients harbored hyalinized cytoplasmic inclusions in smooth muscle cells and 1 of them had polyglucosan bodies in the muscularis propria. CONCLUSIONS: Apart from hyalinized inclusions, which were only observed in 3/16 patients, intestinal pathology in the majority of patients with ACTG2 variants is not indicative of an underlying visceral myopathy. Molecular testing should be considered even when no diagnostic intestinal pathology is identified.

Molecular Targets to Alleviate Enteric Neuropathy and Gastrointestinal Dysfunction.

Enteric neuropathy underlies long-term gastrointestinal (GI) dysfunction associated with several pathological conditions. Our previous studies have demonstrated that structural and functional changes in the enteric nervous system (ENS) result in persistent alterations of intestinal functions long after the acute insult. These changes lead to aberrant immune response and chronic dysregulation of the epithelial barrier. Damage to the ENS is prognostic of disease progression and plays an important role in the recurrence of clinical manifestations. This suggests that the ENS is a viable therapeutic target to alleviate chronic intestinal dysfunction. Our recent studies in preclinical animal models have progressed into the development of novel therapeutic strategies for the treatment of enteric neuropathy in various chronic GI disorders. We have tested the anti-inflammatory and neuroprotective efficacy of novel compounds targeting specific molecular pathways. Ex vivo studies in human tissues freshly collected after resection surgeries provide an understanding of the molecular mechanisms involved in enteric neuropathy. In vivo treatments in animal models provide data on the efficacy and the mechanisms of actions of the novel compounds and their combinations with clinically used therapies. These novel findings provide avenues for the development of safe, cost-effective, and highly efficacious treatments of GI disorders.

Phenotypic switch of smooth muscle cells in paediatric chronic intestinal pseudo-obstruction syndrome.

Smooth Muscle Cells (SMC) are unique amongst all muscle cells in their capacity to modulate their phenotype. Indeed, SMCs do not terminally differentiate but instead harbour a remarkable capacity to dedifferentiate, switching between a quiescent contractile state and a highly proliferative and migratory phenotype, a quality often associated to SMC dysfunction. However, phenotypic plasticity remains poorly examined in the field of gastroenterology in particular in pathologies in which gut motor activity is impaired. Here, we assessed SMC status in biopsies of infants with chronic intestinal pseudo-obstruction (CIPO) syndrome, a life-threatening intestinal motility disorder. We showed that CIPO-SMCs harbour a decreased level of contractile markers. This phenotype is accompanied by an increase in Platelet-Derived Growth Factor Receptor-alpha (PDGFRA) expression. We showed that this modulation occurs without origin-related differences in CIPO circular and longitudinal-derived SMCs. As we characterized PDGFRA as a marker of digestive mesenchymal progenitors during embryogenesis, our results suggest a phenotypic switch of the CIPO-SMC towards an undifferentiated stage. The development of CIPO-SMC culture and the characterization of SMC phenotypic switch should enable us to design therapeutic approaches to promote SMC differentiation in CIPO.

Visceral myopathy: clinical syndromes, genetics, pathophysiology, and fall of the cytoskeleton.

Visceral smooth muscle is a crucial component of the walls of hollow organs like the gut, bladder, and uterus. This specialized smooth muscle has unique properties that distinguish it from other muscle types and facilitate robust dilation and contraction. Visceral myopathies are diseases where severe visceral smooth muscle dysfunction prevents efficient movement of air and nutrients through the bowel, impairs bladder emptying, and affects normal uterine contraction and relaxation, particularly during pregnancy. Disease severity exists along a spectrum. The most debilitating defects cause highly dysfunctional bowel, reduced intrauterine colon growth (microcolon), and bladder-emptying defects requiring catheterization, a condition called megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS). People with MMIHS often die early in childhood. When the bowel is the main organ affected and microcolon is absent, the condition is known as myopathic chronic intestinal pseudo-obstruction (CIPO). Visceral myopathies like MMIHS and myopathic CIPO are most commonly caused by mutations in contractile apparatus cytoskeletal proteins. Here, we review visceral myopathy-causing mutations and normal functions of these disease-associated proteins. We propose molecular, cellular, and tissue-level models that may explain clinical and histopathological features of visceral myopathy and hope these observations prompt new mechanistic studies.

Evidence of enteric angiopathy and neuromuscular hypoxia in patients with mitochondrial neurogastrointestinal encephalomyopathy.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive disease caused by thymidine phosphorylase (TP) enzyme defect. As gastrointestinal changes do not revert in patients undergone TP replacement therapy, one can postulate that other unexplored mechanisms contribute to MNGIE pathophysiology. Hence, we focused on the local TP angiogenic potential that has never been considered in MNGIE. In this study, we investigated the enteric submucosal microvasculature and the effect of hypoxia on fibrosis and enteric neurons density in jejunal full-thickness biopsies collected from patients with MNGIE. Orcein staining was used to count blood vessels based on their size. Fibrosis was assessed using the Sirius Red and Fast Green method. Hypoxia and neoangiogenesis were determined via hypoxia-inducible-factor-1α (HIF-1α) and vascular endothelial cell growth factor (VEGF) protein expression, respectively. Neuron-specific enolase was used to label enteric neurons. Compared with controls, patients with MNGIE showed a decreased area of vascular tissue, but a twofold increase of submucosal vessels/mm2 with increased small size and decreased medium and large size vessels. VEGF positive vessels, fibrosis index, and HIF-1α protein expression were increased, whereas there was a diminished thickness of the longitudinal muscle layer with an increased interganglionic distance and reduced number of myenteric neurons. We demonstrated the occurrence of an angiopathy in the GI tract of patients with MNGIE. Neoangiogenetic changes, as detected by the abundance of small size vessels in the jejunal submucosa, along with hypoxia provide a morphological basis to explain neuromuscular alterations, vasculature breakdown, and ischemic abnormalities in MNGIE.NEW & NOTEWORTHY Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is characterized by a genetically driven defect of thymidine phosphorylase, a multitask enzyme playing a role also in angiogenesis. Indeed, major gastrointestinal bleedings are life-threatening complications of MNGIE. Thus, we focused on jejunal submucosal vasculature and showed intestinal microangiopathy as a novel feature occurring in this disease. Notably, vascular changes were associated with neuromuscular abnormalities, which may explain gut dysfunction and help to develop future therapeutic approaches in MNGIE.

Efficacy of prucalopride in critically ill patients with paralytic ileus: A pilot randomized double-blind placebo-controlled trial.

BACKGROUND AND AIM: Paralytic ileus is a common intestinal dysfunction in critically ill patients, which results in complications and poor hospital outcomes. There are still no established effective medications, except correcting the primary causes and prokinetics trial, which have limited efficacy and potential adverse events. This study aims to evaluate the efficacy of prucalopride on paralytic ileus in critically ill patients. METHODS: A randomized, double-blind, placebo-controlled trial of five consecutive days treatment periods was conducted. Critically ill patients with paralytic ileus were included. The primary endpoint was the improvement of bowel dilatation on plain abdominal radiography. The secondary endpoint was the change of abdominal circumference. RESULTS: Twenty patients were consecutively enrolled in the study. There was no significant difference in baseline characteristics of patients. The common causes of hospitalization were infection and respiratory problems. The maximum large bowel diameters dramatically decreased in prucalopride group and reached maximum point on the third day after intervention when compared with placebo (-2.1 [± 1.8] vs 0.3 [± 1.5] cm, P = 0.01). The maximum small bowel diameters were noticeably less decreased and were not significantly different when compared with placebo. The abdominal circumferences notably decreased and significantly diverged from placebo on the third day. CONCLUSIONS: Prucalopride was an effective enterokinetic agent to improve non-severe inflammatory/ischemic bowel conditions related paralytic ileus in critically ill patients. Its effect was predominant on large intestine but could not be well demonstrated on small bowel in this study. Future study or concomitant other prokinetics for upper gut motility should be further evaluated.

Esophageal High-Resolution Manometry for Diagnosing the Severity of the Chronic Intestinal Pseudo-Obstruction: A Case Series.

BACKGROUND: Chronic intestinal pseudo-obstruction (CIPO) is a severe and refractory intestinal motility disorder. However, due to its rarity and difficult histological investigation, its pathophysiology has not been characterized. AIM: Therefore, in this study, we aimed to determine the role of esophageal high-resolution manometry (HRM) in CIPO and the histological and clinical characteristics of the disease. METHODS: Patients with CIPO were analyzed for clinical characteristics; histological findings; and clinical courses after therapeutic intervention. In addition, HRM was performed to determine the esophageal involvement. RESULTS: Eleven patients were diagnosed with CIPO, and five required the long period of parenteral nutrition showing impaired esophageal motility including achalasia and absent contractility diagnosed with HRM. The four of these five cases showed acute onset of the CIPO following the triggering events of pregnancy, appendicitis, and surgery. In contrast, other six patients with normal or Jackhammer esophagus on HRM had moderate severity of CIPO with gradual onset. The histological analyses revealed that the loss of the intestinal neural ganglion cells and layers by inflammation, destruction, and atrophy are related to the severity of the clinical course of the disease and esophageal HRM findings of achalasia and absent contractility. CONCLUSIONS: HRM may be useful to diagnose the severity of the clinical course and to determine the therapeutic options for CIPO.

Fetal megacystis-microcolon: Genetic mutational spectrum and identification of PDCL3 as a novel candidate gene.

Megacystis-microcolon-intestinal-hypoperistalsis syndrome (MMIHS) is a severe congenital visceral myopathy characterized by an abdominal distension due to a large non-obstructed urinary bladder, a microcolon and intestinal hypo- or aperistalsis. Most of the patients described to date carry a sporadic heterozygous variant in ACTG2. More recently, recessive forms have been reported and mutations in MYH11, LMOD1, MYLK and MYL9 have been described at the molecular level. In the present report, we describe five patients carrying a recurrent heterozygous variant in ACTG2. Exome sequencing performed in four families allowed us to identify the genetic cause in three. In two families, we identified variants in MMIHS causal genes, respectively a nonsense homozygous variant in MYH11 and a previously described homozygous deletion in MYL9. Finally, we identified compound heterozygous variants in a novel candidate gene, PDCL3, c.[143_144del];[380G>A], p.[(Tyr48Ter)];[(Cys127Tyr)]. After cDNA analysis, a complete absence of PDLC3 expression was observed in affected individuals, indicating that both mutated transcripts were unstable and prone to mediated mRNA decay. PDCL3 encodes a protein involved in the folding of actin, a key step in thin filament formation. Presumably, loss-of-function of this protein affects the contractility of smooth muscle tissues, making PDCL3 an excellent candidate gene for autosomal recessive forms of MMIHS.

Identification of a dominant MYH11 causal variant in chronic intestinal pseudo-obstruction: Results of whole-exome sequencing.

Chronic Intestinal Pseudo-Obstruction (CIPO) is a rare gastrointestinal disorder, which affects the smooth muscle contractions of the gastrointestinal tract. Dominant mutations in the smooth muscle actin gene, ACTG2, accounts for 44%-50% of CIPO patients. Other recessive or X-linked genes, including MYLK, LMOD1, RAD21, MYH11, MYL9, and FLNA were reported in single cases. In this study, we used Whole-Exome Sequencing (WES) to study 23 independent CIPO families including one extended family with 13 affected members. A dominantly inherited rare mutation, c.5819delC (p.Pro1940HisfsTer91), in the smooth muscle myosin gene, MYH11, was found in the extended family, shared by 7 affected family members but not by 3 unaffected family members with available DNA, suggesting a high probability of genetic linkage. Gene burden analysis indicates that additional genes, COL4A1, FBLN1 and HK2, may be associated with the disease. This study expanded our understanding of CIPO etiology and provided additional genetic evidence to physicians and genetic counselors for CIPO diagnosis.

Fetal megacystis: a lot more than LUTO.

OBJECTIVE: Fetal megacystis presents a challenge in terms of counseling and management because of its varied etiology and evolution. The aim of this study was to present a comprehensive overview of the underlying etiologies and structural anomalies associated with fetal megacystis. METHODS: This was a retrospective multicenter study of cases referred to the fetal medicine unit of one of the eight academic hospitals in The Netherlands with a diagnosis of fetal megacystis. For each case, data on and measurements of fetal urinary tract and associated structural anomalies were collected. All available postmortem examinations and postnatal investigations were reviewed in order to establish the final diagnosis. In the first trimester, fetal megacystis was defined as longitudinal bladder diameter (LBD) ≥ 7 mm, and in the second and third trimesters as an enlarged bladder failing to empty during an extended ultrasound examination lasting at least 40 min. RESULTS: Of the 541 pregnancies with fetal megacystis, it was isolated (or solely accompanied by other signs of lower urinary tract obstruction (LUTO)) in 360 (67%) cases and associated with other abnormal ultrasound findings in 181 (33%) cases. The most common associated ultrasound anomaly was an increased nuchal translucency thickness (22%), followed by single umbilical artery (10%) and cardiac defect (10%). A final diagnosis was established in 418 cases, including 222 (53%) cases with isolated LUTO and 60 (14%) infants with normal micturition or minor isolated urological anomalies. In the remaining 136 (33%) cases, concomitant developmental or chromosomal abnormality or genetic syndrome was diagnosed. Overall, 40 chromosomal abnormalities were diagnosed, including trisomy 18 (n = 24), trisomy 21 (n = 5), Turner syndrome (n = 5), trisomy 13 (n = 3) and 22q11 deletion (n = 3). Thirty-two cases presented with anorectal malformations involving the anus, rectum and urogenital tract. In cases with confirmed urethral and anal atresia, megacystis occurred early in pregnancy and the bladder appeared severely distended (the LBD (in mm) was equal to or greater than twice the gestational age (in weeks)). Fetal macrosomia was detected in six cases and an overgrowth syndrome was detected in four cases, comprising two infants with Beckwith-Wiedemann syndrome and two with Sotos syndrome. Megacystis-microcolon-intestinal hypoperistalsis syndrome was diagnosed in five (1%) cases and prenatally suspected only in one case. CONCLUSIONS: Although the main cause of fetal megacystis is LUTO, an enlarged fetal bladder can also be present as a concomitant finding of miscellaneous genetic syndromes, developmental disturbances and chromosomal abnormalities. We provide an overview of the structural anomalies and congenital disorders associated with fetal megacystis and propose a practical guide for the differential diagnosis of genetic syndromes and chromosomal and developmental abnormalities in pregnancies presenting with fetal megacystis, focusing on the morphological examination of the fetus. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

ACTG2 variants impair actin polymerization in sporadic Megacystis Microcolon Intestinal Hypoperistalsis Syndrome.

Megacystis Microcolon Intestinal Hypoperistalsis Syndrome (MMIHS) is a rare congenital disorder, in which heterozygous missense variants in the Enteric Smooth Muscle actin γ-2 (ACTG2) gene have been recently identified. To investigate the mechanism by which ACTG2 variants lead to MMIHS, we screened a cohort of eleven MMIHS patients, eight sporadic and three familial cases, and performed immunohistochemistry, molecular modeling and molecular dynamics (MD) simulations, and in vitro assays. In all sporadic cases, a heterozygous missense variant in ACTG2 was identified. ACTG2 expression was detected in all intestinal layers where smooth muscle cells are present in different stages of human development. No histopathological abnormalities were found in the patients. Using molecular modeling and MD simulations, we predicted that ACTG2 variants lead to significant changes to the protein function. This was confirmed by in vitro studies, which showed that the identified variants not only impair ACTG2 polymerization, but also contribute to reduced cell contractility. Taken together, our results confirm the involvement of ACTG2 in sporadic MMIHS, and bring new insights to MMIHS pathogenesis.

Clinical characteristics of lupus enteritis in Japanese patients: the large intestine-dominant type has features of intestinal pseudo-obstruction.

This study was performed to investigate the clinical characteristics of lupus enteritis in Japanese patients with systemic lupus erythematosus (SLE). A total of 481 patients with SLE admitted to our hospital between 2001 and 2015 were retrospectively reviewed. Diagnosis of lupus enteritis was based on the following three criteria: (1) abdominal symptoms, (2) diffuse long-segment bowel thickening and (3) a requirement for glucocorticoid therapy. Lupus enteritis was identified in 17 patients (3.5%) and there were two distinct types: small intestine-dominant and large intestine-dominant. Significant differences between the two types were noted with respect to the age, frequency of biopsy-proven lupus nephritis, frequency of rectal involvement, maximum bowel wall thickness, and requirement for steroid pulse therapy. Among patients with large intestine-dominant lupus enteritis, 60% had extra-intestinal symptoms (hydroureter, bladder wall thickening, and bile duct dilatation) that are known complications of intestinal pseudo-obstruction. Two patients with large intestine-dominant lupus enteritis developed intestinal pseudo-obstruction either before or after diagnosis of lupus enteritis. Five patients (29%) developed recurrence during a median observation period of 7.2 years (1.4-14.4 years). In conclusion, large intestine-dominant lupus enteritis resembles intestinal pseudo-obstruction and these two diseases may have a common pathogenesis.

Diagnostic Criteria of Pediatric Intestinal Myopathies.

The authors aim to identify criteria for the diagnosis of intestinal visceral myopathy (IVM); results were compared with ultrastructural studies. Six IVM patients and 7 pediatric control cases (without gastrointestinal diseases) were studied. One case was a typical megacystis-microcolon-intestinal hypoperistalsis syndrome. The diagnostic path included: rectal suction biopsy, one-trocar transumbilical laparoscopic intestinal full-thickness biopsy technique. Pathological analysis included anti-alpha smooth muscle actin staining, and US study of intestinal biopsies. IVM histological examination demonstrated thinning of longitudinal muscle layer. The ratio of circular/longitudinal thickness was evaluated in all samples; in cases, this ratio presented as a mean value of 2.91, and in controls, a mean value of 1.472 (P = 0.0002). Ultrastructural diagnosis revealed variable myofibrils density in smooth muscle cells, irregularity of sarcolemma membranes, interstitial fibrosis, and myofiber disarray. The authors concluded that in IVM, circular/longitudinal thickness ratio and alpha smooth muscle actin staining can be used as significant tools to address the diagnosis.

Congenital Short-Bowel Syndrome in an Adult Dog.

A 3.5-year-old, neutered male pit bull dog was euthanized following an approximately 1-year history of intractable diarrhea and weight loss of undetermined cause. At necropsy, the dog was emaciated. The ratio of total intestinal length (duodenum to rectum) to crown-to-rump length was 2.5, in contrast to an average of 5.3 (range, 3.7-6.1) in 10 control dogs examined at necropsy. There was diffuse dilation of the intestinal lumen, consistent with congenital intestinal hypoplasia resulting in short-bowel syndrome. Histologically, the intestinal mucosal was hyperplastic, further supporting the diagnosis of short-bowel syndrome. To the authors' knowledge, this is the first case of this condition in the veterinary literature.

White paper on guidelines concerning enteric nervous system stem cell therapy for enteric neuropathies.

Over the last 20 years, there has been increasing focus on the development of novel stem cell based therapies for the treatment of disorders and diseases affecting the enteric nervous system (ENS) of the gastrointestinal tract (so-called enteric neuropathies). Here, the idea is that ENS progenitor/stem cells could be transplanted into the gut wall to replace the damaged or absent neurons and glia of the ENS. This White Paper sets out experts' views on the commonly used methods and approaches to identify, isolate, purify, expand and optimize ENS stem cells, transplant them into the bowel, and assess transplant success, including restoration of gut function. We also highlight obstacles that must be overcome in order to progress from successful preclinical studies in animal models to ENS stem cell therapies in the clinic.

Clinical aspects of neurointestinal disease: Pathophysiology, diagnosis, and treatment.

The enteric nervous system (ENS) is involved in the regulation of virtually all gut functions. Conditions referred to as enteric neuropathies are the result of various mechanisms including abnormal development, degeneration or loss of enteric neurons that affect the structure and functional integrity of the ENS. In the past decade, clinical and molecular research has led to important conceptual advances in our knowledge of the pathogenetic mechanisms of these disorders. In this review we consider ENS disorders from a clinical perspective and highlight the advancing knowledge regarding their pathophysiology. We also review current therapies for these diseases and present potential novel reparative approaches for their treatment.