The transition zone in Hirschsprung's bowel contains abnormal hybrid ganglia with characteristics of extrinsic nerves.

The aganglionic bowel in short-segment Hirschsprung's disease is characterized both by the absence of enteric ganglia and the presence of extrinsic thickened nerve bundles (TNBs). The relationship between the TNBs and the loss of enteric ganglia is unknown. Previous studies have described decreasing numbers of ganglia with increasing density of TNBs within the transition zone (TZ) between ganglionic and aganglionic gut, and there is some evidence of spatial contact between them in this region. To determine the cellular interactions involved, we have analysed the expression of perineurial markers of TNBs and enteric ganglionic markers for both neural cells and their ensheathing telocytes across four cranio-caudal segments consisting of most proximal ganglionic to most distal aganglionic from pull-through resected colon. We show that in the TZ, enteric ganglia are abnormal, being surrounded by perineurium cells characteristic of TNBs. Furthermore, short processes of ganglionic neurons extend caudally towards the aganglionic region, where telocytes in the TNB are located between the perineurium and nerve fibres into which they project telopodes. Thus, enteric ganglia within the TZ have abnormal structural characteristics, the cellular relationships of which are shared by the TNBs. These findings will help towards elucidation of the cellular mechanisms involved in the aetiology of Hirschsprung's disease.

Luvadaxistat: A Novel Potent and Selective D-Amino Acid Oxidase Inhibitor Improves Cognitive and Social Deficits in Rodent Models for Schizophrenia.

N-methyl-D-aspartate (NMDA) receptor hypofunctionality is a well-studied hypothesis for schizophrenia pathophysiology, and daily dosing of the NMDA receptor co-agonist, D-serine, in clinical trials has shown positive effects in patients. Therefore, inhibition of D-amino acid oxidase (DAAO) has the potential to be a new therapeutic approach for the treatment of schizophrenia. TAK-831 (luvadaxistat), a novel, highly potent inhibitor of DAAO, significantly increases D-serine levels in the rodent brain, plasma, and cerebrospinal fluid. This study shows luvadaxistat to be efficacious in animal tests of cognition and in a translational animal model for cognitive impairment in schizophrenia. This is demonstrated when luvadaxistat is dosed alone and in conjunction with a typical antipsychotic. When dosed chronically, there is a suggestion of change in synaptic plasticity as seen by a leftward shift in the maximum efficacious dose in several studies. This is suggestive of enhanced activation of NMDA receptors in the brain and confirmed by modulation of long-term potentiation after chronic dosing. DAAO is highly expressed in the cerebellum, an area of increasing interest for schizophrenia, and luvadaxistat was shown to be efficacious in a cerebellar-dependent associative learning task. While luvadaxistat ameliorated the deficit seen in sociability in two different negative symptom tests of social interaction, it failed to show an effect in endpoints of negative symptoms in clinical trials. These results suggest that luvadaxistat potentially could be used to improve cognitive impairment in patients with schizophrenia, which is not well addressed with current antipsychotic medications.

Novel TRPM8 antagonist attenuates cold hypersensitivity after peripheral nerve injury in rats.

Abnormal cold sensitivity is a common feature of a range of neuropathies. In the murine somatosensory system, multiple aspects of cold sensitivity are dependent on TRPM8, both short term and in response to peripheral nerve injury. The specialized nature of cold-sensitive afferents and the restricted expression of TRPM8 render it an attractive target for the treatment of cold hypersensitivity. This current study examines the effect of a novel TRPM8 antagonist (M8-An) in naive and spinal nerve-ligated rats through behavioral and in vivo electrophysiological approaches. In vitro, M8-An inhibited icilin-evoked Ca(2+) currents in HEK293 cells stably expressing human TRPM8 with an IC(50) of 10.9 nM. In vivo, systemic M8-An transiently decreased core body temperature. Deep dorsal horn recordings were made in vivo from neurons innervating the hind paw. M8-An inhibited neuronal responses to innocuous and noxious cooling of the receptive field in spinal nerve-ligated rats but not in naive rats. No effect on neuronal responses to mechanical and heat stimulation was observed. In addition, M8-An also attenuated behavioral responses to cold but not mechanical stimulation after nerve ligation without affecting the uninjured contralateral response. The data presented here support a contribution of TRPM8 to the pathophysiology of cold hypersensitivity in this model and highlight the potential of the pharmacological block of TRPM8 in alleviating the associated symptoms.

Autologous intestinal reconstructive surgery to reduce bowel dilatation improves intestinal adaptation in children with short bowel syndrome.

OBJECTIVES: Intestinal failure (IF) is a common consequence of neonatal small bowel pathology. In our experience, bowel dilatation is often responsible for the IF state in patients who fail to adapt despite adequate residual bowel length. The aim of the present study was to investigate the role of surgery to reduce bowel dilatation, and thus favour PN independence, for these children. METHODS: Data were collected prospectively for all of the patients referred to our unit for a 7-year period (2004-2011). Eight patients (2 congenital atresia, 2 gastroschisis with atresia, 1 simple gastroschisis, 3 necrotising enterocolitis) with gut dilatation who failed adaptation despite a bowel length >40 cm were identified. Preoperatively, all patients were totally dependent on parenteral nutrition (PN). Patients were managed by longitudinal intestinal lengthening and tailoring (n = 3), serial transverse enteroplasty (n = 2), or tapering enteroplasty (n = 3). RESULTS: Median age at time of surgery was 273 days (103-1059). Mean gut length increased from 51 (35-75) to 73 cm (45-120) following surgery (P = 0.02). Incidence of sepsis (P = 0.01) and peak serum bilirubin levels (P = 0.005) were reduced postoperatively. PN was discontinued after a median of 110 days (35-537) for 7 patients; 1 patient remains on PN 497 days after surgery. CONCLUSIONS: These data indicate that reconstructive surgery to reduce bowel diameter may be an effective technique for treating IF in patients with short bowel syndrome, without sacrificing intestinal length. We suggest that this technique may reduce the need for bowel transplantation in this group of patients.

Knockout or inhibition of USP30 protects dopaminergic neurons in a Parkinson's disease mouse model.

Mutations in SNCA, the gene encoding α-synuclein (αSyn), cause familial Parkinson's disease (PD) and aberrant αSyn is a key pathological hallmark of idiopathic PD. This α-synucleinopathy leads to mitochondrial dysfunction, which may drive dopaminergic neurodegeneration. PARKIN and PINK1, mutated in autosomal recessive PD, regulate the preferential autophagic clearance of dysfunctional mitochondria ("mitophagy") by inducing ubiquitylation of mitochondrial proteins, a process counteracted by deubiquitylation via USP30. Here we show that loss of USP30 in Usp30 knockout mice protects against behavioral deficits and leads to increased mitophagy, decreased phospho-S129 αSyn, and attenuation of SN dopaminergic neuronal loss induced by αSyn. These observations were recapitulated with a potent, selective, brain-penetrant USP30 inhibitor, MTX115325, with good drug-like properties. These data strongly support further study of USP30 inhibition as a potential disease-modifying therapy for PD.

Discovery of CVN636: A Highly Potent, Selective, and CNS Penetrant mGluR7 Allosteric Agonist.

The low affinity metabotropic glutamate receptor mGluR7 has been implicated in numerous CNS disorders; however, a paucity of potent and selective activators has hampered full delineation of the functional role and therapeutic potential of this receptor. In this work, we present the identification, optimization, and characterization of highly potent, novel mGluR7 agonists. Of particular interest is the chromane CVN636, a potent (EC50 7 nM) allosteric agonist which demonstrates exquisite selectivity for mGluR7 compared to not only other mGluRs, but also a broad range of targets. CVN636 demonstrated CNS penetrance and efficacy in an in vivo rodent model of alcohol use disorder. CVN636 thus has potential to progress as a drug candidate in CNS disorders involving mGluR7 and glutamatergic dysfunction.

Routine evaluation of vesico-ureteric reflux in children with anorectal malformation does not reduce the rate of urinary tract infection.

OBJECTIVE: Children with anorectal malformations (ARM) have a high rate of renal anomalies and increased risk of urinary tract infection (UTI). We aimed to determine whether using routine Micturating Cystourethrogram (MCUG) to detect VUR is effective in reducing the incidence of UTI or renal scarring in children with ARM. METHODS: A retrospective study of consecutive children diagnosed with ARM in two centres with a minimum of 3 years follow-up was performed, excluding those with cloaca or an MCUG prior to ARM repair. Univariate and multivariate logistic regression analysis was used to determine variables which were associated with VUR, UTI and renal scarring. Associations are described as Odd's Ratio (OR), 95% Confidence Interval. Significance was taken as p<0.05. RESULTS: 344 children were included with a median age of 8 years (IQR 5-11 years). 150 (44%) were female. 89 (26%) had renal anomalies and 101 (29%) had spine anomalies. 148 patients had routine MCUG and VUR was found in 62 (42%) of these children. Univariate analysis did not correlate any of the assessed variables with VUR or renal scarring. However, abnormal renal ultrasound - OR 6.18 (95% CI 2.99-13.07, p 0.0001) was associated with UTI whilst abnormal spine - OR 0.27 (95% CI 0.10-0.62, p 0.009), low ARM - OR 0.30 (CI 0.14-0.63, p 0.006) and intermediate ARM - OR 0.35 (CI 0.17-0.70, p 0.01) were associated with a reduced risk of UTI. On multivariate analysis, only abnormal renal USS retained a significant association with UTI (p<0.0001). CONCLUSIONS: VUR is common in patients with ARM. Children with an abnormal R-USS are at increased risk of UTI. Performing routine MCUG does not reduce the risk of UTI in children with ARM.

A national consensus management pathway for paediatric inflammatory multisystem syndrome temporally associated with COVID-19 (PIMS-TS): results of a national Delphi process.

Paediatric inflammatory multisystem syndrome temporally associated with COVID-19 (PIMS-TS) is a novel condition that was first reported in April, 2020. We aimed to develop a national consensus management pathway for the UK to provide guidance for clinicians caring for children with PIMS-TS. A three-phase online Delphi process and virtual consensus meeting sought consensus over the investigation, management, and research priorities from multidisciplinary clinicians caring for children with PIMS-TS. We used 140 consensus statements to derive a consensus management pathway that describes the initial investigation of children with suspected PIMS-TS, including blood markers to help determine the severity of disease, an echocardiogram, and a viral and septic screen to exclude other infectious causes of illness. The importance of a multidisciplinary team in decision making for children with PIMS-TS is highlighted throughout the guidance, along with the recommended treatment options, including supportive care, intravenous immunoglobulin, methylprednisolone, and biological therapies. These include IL-1 antagonists (eg, anakinra), IL-6 receptor blockers (eg, tocilizumab), and anti-TNF agents (eg, infliximab) for children with Kawasaki disease-like phenotype and non-specific presentations. Use of a rapid online Delphi process has made it possible to generate a national consensus pathway in a timely and cost-efficient manner in the middle of a global pandemic. The consensus statements represent the views of UK clinicians and are applicable to children in the UK suspected of having PIMS-TS. Future evidence will inform updates to this guidance, which in the interim provides a solid framework to support clinicians caring for children with PIMS-TS. This process has directly informed new PIMS-TS specific treatment groups as part of the adaptive UK RECOVERY trial protocol, which is the first formal randomised controlled trial of therapies for PIMS-TS globally.

Paediatric abdominal pain in the time of COVID-19: a new diagnostic dilemma.

The diagnostic uncertainty for children with abdominal pain has increased during the COVID-19 pandemic with the additional consideration of both COVID-19 and paediatric inflammatory multisystem syndrome-temporally associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (PIMS-TS) alongside appendicitis, mesenteric adenitis and other less common causes of abdominal pain. We describe the cases of two children who presented with severe abdominal pain, non-bilious vomiting and high temperatures during the UK's first peak of the COVID-19 pandemic. Laboratory and abdominal ultrasound features were similar for both children but symptom progression in combination with cross-sectional abdominal imaging enabled differentiation between PIMS-TS and appendicitis with concurrent COVID-19. These cases highlight the importance of regular clinical review, multidisciplinary working and the utility of early cross-sectional imaging to determine the underlying condition.

APC and AXIN2 Are Promising Biomarker Candidates for the Early Detection of Adenomas and Hyperplastic Polyps.

Aberrant activation of the WNT/CTNNB1 pathway is notorious in colorectal cancer (CRC). Here, we demonstrate that the expression of specific and crucial WNT signaling pathway genes is linked to disease progression in colonic adenomatous (AP) and hyperplastic (HP) polyps in an Iranian patient population. Thus, we highlight potential gene expression profiles as candidate novel biomarkers for the early detection of CRC. From a 12-month study (2016-2017), 44 biopsy samples were collected during colonoscopy from the patients with colorectal polyps and 10 healthy subjects for normalization. Clinical and demographic data were collected in all cases, and mRNA expression of APC, CTNNB1, CDH1, AXIN1, and AXIN2 genes was investigated using real-time polymerase chain reaction (PCR). CTNNB1 and CDH1 expression levels were unaltered in AP and HP subjects, whereas mRNA expression of APC was decreased in AP contrasted with HP subjects, with a significant association between APC downregulation and polyp size. Although AXIN1 showed no changes between AP and HP groups, a significant association between AXIN1 and dysplasia grade was found. Also, significant upregulation of AXIN2 in both AP and HP subjects was detected. In summary, we have shown increased expression of AXIN2 and decreased expression of APC correlating with grade of dysplasia and polyp size. Hence, AXIN2 and APC should be explored as biomarker candidates for early detection of AP and HP polyps in CRC.

Human and mouse enteric nervous system neurosphere transplants regulate the function of aganglionic embryonic distal colon.

BACKGROUND & AIMS: Recent advances have raised the possibility of treating enteric nervous system (ENS) disorders with transplanted progenitor cells (ENSPC). Although these cells have been shown to migrate and differentiate after transplantation, no functional effects have been demonstrated. We therefore aimed to investigate whether embryonic mouse and neonatal human ENSPC can regulate the contractility of aganglionic bowel. METHODS: Embryonic mouse and neonatal human ENSPC were grown as neurospheres before transplantation into aganglionic embryonic mouse hindgut explants and culture for 8-12 days. Engraftment and neural differentiation were confirmed using immunofluorescence and transmission electron microscopy. The contraction frequency of transplanted bowel was measured and compared with that of embryonic day 11.5 embryonic ganglionic and aganglionic bowel cultured for the same period. Calcium movement was measured at spatially defined points in bowel wall smooth muscle. Neural modulation of bowel contractility was assessed using tetrodotoxin. RESULTS: Both mouse and human ENSPC migrated and differentiated after neurosphere transplantation. Transmission electron microscopy demonstrated the existence of synapses. Transplantation restored the high contraction frequency of aganglionic bowel to the lower rate of ganglionic bowel. Calcium imaging demonstrated that neurosphere transplantation coordinates intracellular free calcium levels. Both these effects were reversed by the addition of tetrodotoxin, indicating the functional effect of neurosphere-derived neurons. CONCLUSIONS: Neonatal human gut is a source of ENSPC that can be transplanted to restore the contractile properties of aganglionic bowel by a neurally mediated mechanism. This may aid development of a stem cell-based treatment for Hirschsprung's disease.

Behavioral and neurochemical alterations in mice deficient in anaplastic lymphoma kinase suggest therapeutic potential for psychiatric indications.

The receptor tyrosine kinase product of the anaplastic lymphoma kinase (ALK) gene has been implicated in oncogenesis as a product of several chromosomal translocations, although its endogeneous role in the hematopoietic and neural systems has remained poorly understood. We describe that the generation of animals homozygous for a deletion of the ALK tyrosine kinase domain leads to alterations in adult brain function. Evaluation of adult ALK homozygotes (HOs) revealed an age-dependent increase in basal hippocampal progenitor proliferation and alterations in behavioral tests consistent with a role for this receptor in the adult brain. ALK HO animals displayed an increased struggle time in the tail suspension test and the Porsolt swim test and enhanced performance in a novel object-recognition test. Neurochemical analysis demonstrates an increase in basal dopaminergic signalling selectively within the frontal cortex. Altogether, these results suggest that ALK functions in the adult brain to regulate the function of the frontal cortex and hippocampus and identifies ALK as a new target for psychiatric indications, such as schizophrenia and depression, with an underlying deregulated monoaminergic signalling.

The discovery of fused pyrrole carboxylic acids as novel, potent D-amino acid oxidase (DAO) inhibitors.

The 'NMDA hypofunction hypothesis of schizophrenia' can be tested in a number of ways. DAO is the enzyme primarily responsible for the metabolism of d-serine, a co-agonist for the NMDA receptor. We identified novel DAO inhibitors, in particular, acid 1, which demonstrated moderate potency for DAO in vitro and ex vivo, and raised plasma d-serine levels after dosing ip to rats. In parallel, analogues were prepared to survey the SARs of 1.

Making an informed choice tailored to each patient.

Nutritional supplements can be useful when the diet alone cannot provide adequate nutrition. They can also be used to manage certain clinical conditions. Once a decision is made to use them it is important to consider patient choice and cultural beliefs as well as which nutrients to supply.

Atropine sulphate: rescue therapy for pyloric stenosis.

Infantile hypertrophic pyloric stenosis (IHPS) is a common condition which presents with non-bilious vomiting and failure to thrive secondary to gastric outlet obstruction. In the UK, management is by fluid resuscitation followed by pyloromyotomy. Incomplete myotomy complicates 0.3% of cases necessitating further surgery and exposing the patient to further risk. Medical management of IHPS with antimuscarinics to promote pyloric relaxation is a well-described treatment modality that is used as first-line therapy in some countries. The use of this technique is limited by the need for extended hospital admission with parenteral nutrition administration. We describe a case of IHPS complicated by incomplete pyloromyotomy and subsequently managed successfully by atropine sulphate therapy.