Adult-onset megacolon with focal hypoganglionosis: A detailed phenotyping and prospective cohort study.

BACKGROUND: In this prospective cohort study, we evaluated features of "adult-onset megacolon with focal hypoganglionosis." METHODS: We assessed the radiologic, endoscopic, and histopathologic phenotyping and treatment outcomes of 29 patients between 2017 and 2020. Data from community controls, consisting of 19,948 adults undergoing health screenings, were analyzed to identify risk factors. Experts reviewed clinical features and pathological specimens according to the London Classification for gastrointestinal neuromuscular pathology. KEY RESULTS: The median age of the patients with adult-onset megacolon with focal hypoganglionosis at symptom onset was 59 years (range, 32.0-74.9 years), with mean symptom onset only 1 year before diagnosis. All patients had focal stenotic regions with proximal bowel dilatation (mean diameter, 78.8 mm; 95% confidence interval [CI], 72-86). The comparison with community controls showed no obvious risk factors. Ten patients underwent surgery, and all exhibited significant hypoganglionosis: 5.4 myenteric ganglion cells/cm (interquartile range [IQR], 3.7-16.4) in the stenotic regions compared to 278 cells/cm (IQR, 190-338) in the proximal and 95 cells/cm (IQR, 45-213) in the distal colon. Hypoganglionosis was associated with CD3+ T cells along the myenteric plexus. Colectomy was associated with significant symptom improvement compared to medical treatment [change in the Global Bowel Satisfaction score, -5.4 points (surgery) vs. -0.3 points (medical treatment); p < 0.001]. CONCLUSIONS AND INFERENCES: Adult-onset megacolon with focal hypoganglionosis has distinct features characterized by hypoganglionosis due to inflammation. Bowel resection appears to benefit these patients.

Reduction in cycle time for a rapid polymerase chain reaction diagnostic test at the point of care.

Background: Rapid testing facilitates safe and effective diagnosis, but the true speed of the process is the time from collection of a sample to delivery of an accurate and reliable test result - 'end-to-end' time. Transport, unpacking and relaying of information can extend this time considerably beyond the minimum laboratory turnaround times as stipulated by PCR testing protocols. Aim/Objective: This study aimed to minimise time needed to ascertain SARS-CoV-2 status prior to treatment in a UK Dental Hospital using a novel, mobile, direct to polymerase chain reaction (PCR) workflow. Methods: Process flow analysis and PDSA (Plan, Do, Study, Act) cycles for rapid continuous improvement were employed in a service improvement programme. Primerdesign™ q16 rapid PCR instruments and PROmate® COVID-19 direct assays were used for molecular testing. Findings/Results: We showed a reduction in real-world end-to-end time for a diagnostic test from 240 min to 85 min (65% reduction) over a 4-week period. Discussion: New rapid technologies have become available that reduce analytical time to under 90 min, but the real-world clinical implementation of the test requires a fully integrated workflow from clinic to reporting.

Perceived feasibility, facilitators and barriers to incorporating point-of-care testing for SARS-CoV-2 into emergency medical services by ambulance service staff: a survey-based approach.

OBJECTIVES: This body of work aimed to elicit ambulance service staff's perceptions on the barriers and facilitators to adoption, and clinical utility of incorporating rapid SARS-CoV-2 testing during ambulance assessments. DESIGN: A mixed-methods survey-based project using a framework analysis method to organise qualitative data. SETTING: Emergency and non-emergency care ambulatory services in the UK were approached to take part. PARTICIPANTS: Current, practising members of the UK ambulance service (paramedics, technicians, assistants and other staff) were included in this body of work. RESULTS: Survey 1: 226 responses were collected between 3 December 2020 and 11 January 2021, 179 (79.2%) of which were completed in full. While the majority of respondents indicated that an ambulance-based testing strategy was feasible in concept (143/190, 75.3%), major barriers to adoption were noted. Many open-ended responses cited concerns regarding misuse of the service by the general public and other healthcare services, timing and conveyance issues, and increased workloads, alongside training and safety concerns. Survey 2: 26 responses were received between 8 February 2021 and 22 February 2021 to this follow-up survey. Survey 2 revealed conveyance decision-making, and risk stratification to be the most frequently prioritised use cases among ambulance service staff. Optimal test characteristics for clinical adoption according to respondents were; accuracy (above 90% sensitivity and specificity), rapidity (<30 min time to results) and ease of sample acquisition. CONCLUSIONS: The majority of commercially available lateral flow devices are unlikely to be supported by paramedics as their duty of care requires both rapid and accurate results that can inform clinical decision making in an emergency situation. Further investigation is needed to define acceptable test characteristics and criteria required for ambulance service staff to be confident and supportive of deployment of a SARS-CoV-2 test in an emergency care setting.

Expression of p16 Within Myenteric Neurons of the Aged Colon: A Potential Marker of Declining Function.

Human colonic neuromuscular functions decline among the elderly. The aim was to explore the involvement of senescence. A preliminary PCR study looked for age-dependent differences in expression of CDKN1A (encoding the senescence-related p21 protein) and CDKN2A (encoding p16 and p14) in human ascending and descending colon (without mucosa) from 39 (approximately 50: 50 male: female) adult (aged 27-60 years) and elderly donors (70-89 years). Other genes from different aging pathways (e.g., inflammation, oxidative stress, autophagy) and cell-types (e.g., neurons, neuron axonal transport) were also examined. Unlike CDKN1A, CDKN2A (using primers for p16 and p14 but not when using p14-specific primers) was upregulated in both regions of colon. Compared with the number of genes appearing to upregulate in association with temporal age, more genes positively associated with increased CDKN2A expression (respectively, 16 and five of 44 genes studied for ascending and descending colon). Confirmation of increased expression of CDKN2A was sought by immunostaining for p16 in the myenteric plexus of colon from 52 patients, using a semi-automated software protocol. The results showed increased staining not within the glial cells (S100 stained), but in the cytoplasm of myenteric nerve cell bodies (MAP2 stained, with identified nucleus) of ascending, but not descending colon of the elderly, and not in the cell nucleus of either region or age group (5,710 neurons analyzed: n = 12-14 for each group). It was concluded that increased p16 staining within the cytoplasm of myenteric nerve cell bodies of elderly ascending (but not descending) colon, suggests a region-dependent, post-mitotic cellular senescence-like activity, perhaps involved with aging of enteric neurons within the colon.

Megarectum: systematic histopathological evaluation of 35 patients and new common pathways in chronic rectal dilatation.

AIMS: Megarectum is well described in the surgical literature but few contemporary pathological studies have been undertaken. There is uncertainty whether 'idiopathic' megarectum is a primary neuromuscular disorder or whether chronic dilatation leads to previously reported and unreported pathological changes. We sought to answer this question. METHODS: Systematic histopathological evaluation (in accord with international guidance) of 35 consecutive patients undergoing rectal excision surgery for megarectum (primary: n=24) or megarectum following surgical correction of anorectal malformation (secondary: n=11) in a UK university hospital with adult/paediatric surgical and gastrointestinal neuropathology expertise. RESULTS: We confirmed some previously reported observations, notably hypertrophy of the muscularis propria (27 of 35, 77.1% of patients) and extensive fibrosis (30 of 35, 85.7% of patients). We also observed unique and previously unreported features including elastosis (19 of 33, 57.6%) and the presence of polyglucosan bodies (15 of 32, 46.9% of patients). In contrast to previous literature, few patients had any strong evidence of specific forms of visceral neuropathy (5 of 35, including 3 plexus duplications) or myopathy (6 of 35, including 3 muscle duplications). All major pathological findings were common to both primary and secondary forms of the disease, implying that these may be a response to chronic rectal distension rather than of primary aetiology. CONCLUSIONS: In the largest case series reported to date, we challenge the current perception of idiopathic megarectum as a primary neuromuscular disease and propose a cellular pathway model for the features present. The severe morphological changes account for some of the irreversibility of the condition and reinforce the need to prevent ongoing rectal distension when first identified.

Patient-specific Alzheimer-like pathology in trisomy 21 cerebral organoids reveals BACE2 as a gene dose-sensitive AD suppressor in human brain.

A population of more than six million people worldwide at high risk of Alzheimer's disease (AD) are those with Down Syndrome (DS, caused by trisomy 21 (T21)), 70% of whom develop dementia during lifetime, caused by an extra copy of ß-amyloid-(Aß)-precursor-protein gene. We report AD-like pathology in cerebral organoids grown in vitro from non-invasively sampled strands of hair from 71% of DS donors. The pathology consisted of extracellular diffuse and fibrillar Aß deposits, hyperphosphorylated/pathologically conformed Tau, and premature neuronal loss. Presence/absence of AD-like pathology was donor-specific (reproducible between individual organoids/iPSC lines/experiments). Pathology could be triggered in pathology-negative T21 organoids by CRISPR/Cas9-mediated elimination of the third copy of chromosome 21 gene BACE2, but prevented by combined chemical ß and γ-secretase inhibition. We found that T21 organoids secrete increased proportions of Aß-preventing (Aß1-19) and Aß-degradation products (Aß1-20 and Aß1-34). We show these profiles mirror in cerebrospinal fluid of people with DS. We demonstrate that this protective mechanism is mediated by BACE2-trisomy and cross-inhibited by clinically trialled BACE1 inhibitors. Combined, our data prove the physiological role of BACE2 as a dose-sensitive AD-suppressor gene, potentially explaining the dementia delay in ~30% of people with DS. We also show that DS cerebral organoids could be explored as pre-morbid AD-risk population detector and a system for hypothesis-free drug screens as well as identification of natural suppressor genes for neurodegenerative diseases.

The management of adult patients with severe chronic small intestinal dysmotility.

Adult patients with severe chronic small intestinal dysmotility are not uncommon and can be difficult to manage. This guideline gives an outline of how to make the diagnosis. It discusses factors which contribute to or cause a picture of severe chronic intestinal dysmotility (eg, obstruction, functional gastrointestinal disorders, drugs, psychosocial issues and malnutrition). It gives management guidelines for patients with an enteric myopathy or neuropathy including the use of enteral and parenteral nutrition.

Spontaneous Restoration of Nutrition Autonomy in a Case of Intestinal Failure Secondary to a Gastrointestinal Neuromuscular Disease.

Polyglucosan inclusion body myopathy (PIBM) is a recently described gastrointestinal neuromuscular disease. Given its rarity, very little is known of its natural history and prognosis. In this case report, we present the first case of PIBM and resultant intestinal failure in which, following 7 years of home parenteral nutrition, gastrointestinal symptoms subsided and nutrition autonomy was restored.

Changes in neuromuscular structure and functions of human colon during ageing are region-dependent.

OBJECTIVE: To determine if human colonic neuromuscular functions decline with increasing age. DESIGN: Looking for non-specific changes in neuromuscular function, a standard burst of electrical field stimulation (EFS) was used to evoke neuronally mediated (cholinergic/nitrergic) contractions/relaxations in ex vivomuscle strips of human ascending and descending colon, aged 35-91 years (macroscopically normal tissue; 239 patients undergoing cancer resection). Then, to understand mechanisms of change, numbers and phenotype of myenteric neurons (30 306 neurons stained with different markers), densities of intramuscular nerve fibres (51 patients in total) and pathways involved in functional changes were systematically investigated (by immunohistochemistry and use of pharmacological tools) in elderly (≥70 years) and adult (35-60 years) groups. RESULTS: With increasing age, EFS was more likely to evoke muscle relaxation in ascending colon instead of contraction (linear regression: n=109, slope 0.49%±0.21%/year, 95% CI), generally uninfluenced by comorbidity or use of medications. Similar changes were absent in descending colon. In the elderly, overall numbers of myenteric and neuronal nitric oxide synthase-immunoreactive neurons and intramuscular nerve densities were unchanged in ascending and descending colon, compared with adults. In elderly ascending, not descending, colon numbers of cell bodies exhibiting choline acetyltransferase immunoreactivity increased compared with adults (5.0±0.6 vs 2.4±0.3 neurons/mm myenteric plexus, p=0.04). Cholinergically mediated contractions were smaller in elderly ascending colon compared with adults (2.1±0.4 and 4.1±1.1 g-tension/g-tissue during EFS; n=25/14; p=0.04); there were no changes in nitrergic function or in ability of the muscle to contract/relax. Similar changes were absent in descending colon. CONCLUSION: In ascending not descending colon, ageing impairs cholinergic function.

Variations in inflammation-related genes may be associated with childhood febrile seizure susceptibility.

PURPOSE: To investigate whether genetic variants in inflammation-related genes are associated with increased risk of childhood-onset febrile seizures. METHOD: Tagging single nucleotide polymorphisms (SNPs) from 19 inflammation-related candidate genes were identified and genotyped on the Sequenom platform in a sample of Caucasian childhood-onset febrile seizures cases (n=98) compared to ethnicity, age and gender matched febrile controls presenting without seizures (n=123). Tests for allelic association were carried out using PLINK. SNPs generating empirical P-values (P<0.05) were analysed in an expanded Caucasian control sample (n=2692) from the 1958 Birth Cohort. RESULTS: Six SNPs generated empirical pointwise significance values P<0.05 in the febrile seizures case-control analysis in the P2X7R (purinergic receptor P2X7), TLR4 (toll-like receptor 4), IL6R (interleukin 6 receptor) and PTGER3 (prostaglandin E receptor 3, subtype EP3) genes. The most significant result was for missense SNP rs208294 in P2X7R (P=0.009); this novel association was supported in the expanded case-control analysis using the 1958 Birth Cohort (pointwise P=0.009, OR=0.63, familywise P=0.039). CONCLUSION: Genetic variants in inflammation-related genes, specifically purinergic receptor P2X7, may be involved in susceptibility to childhood-onset febrile seizures.

Bronchial platelet-activating factor receptor in chronic obstructive pulmonary disease.

BACKGROUND: Bacteria expressing phosphorylcholine (ChoP) co-opt host-expressed platelet-activating factor receptor (PAFR) to adhere to lower airway cells. Cigarette smoke and rhinovirus (RV) infection upregulate PAFR-dependent bacterial adhesion to airway cells in vitro, and in healthy adults smoking increases the proportion of PAFR positive bronchial epithelial cells. To date the effect of chronic obstructive pulmonary disease (COPD) on smoke-induced PAFR is unknown. We therefore sought to test the hypothesis that bronchial PAFR mRNA expression is increased in smokers with chronic obstructive pulmonary disease (COPD), and further increases after RV infection. METHODS: Endobronchial biopsies were obtained by fibreoptic bronchoscopy from healthy non-smokers, smokers without airway obstruction, and smokers with COPD, before and after infection with rhinovirus (RV) serotype 16. Endobronchial PAFR mRNA expression was assessed by quantitative PCR and expressed as a ratio of glyceraldehyde-3-phosphate dehydrogenase. The distribution of PAFR was assessed by immunohistochemistry. RESULTS: Baseline PAFR mRNA expression was increased (p < 0.05) in smokers (n = 16), and smokers with COPD (n = 14) compared with non-smokers (n = 18). In RV16 infected subjects there was no increase in PAFR mRNA expression in either non-smokers (n = 9), smokers (n = 8), or smokers with COPD (n = 7). PAFR immunoreactivity in all 3 groups was predominately restricted to the bronchial epithelium and submucosal glands. CONCLUSIONS: Endobronchial PAFR mRNA is increased in both smokers without airway obstruction and smokers with COPD. We found preliminary evidence that RV16 infection does not increase PAFR mRNA expression in either smokers or smokers with COPD.

Recurrent ascending cholangitis due to small intestinal bacterial overgrowth, gastrointestinal dysmotility and an afferent loop.

We report a complex case involving an extremely rare cause of gastrointestinal dysmotility and an afferent loop, which together predisposed to the development of small intestinal bacterial overgrowth. The bacteria subsequently became multi-resistant. As a further consequence of the dysmotility, repeated bile duct reflux occurred despite the afferent loop being unobstructed. This bile duct reflux produced recurrent sepsis through repeated episodes of ascending cholangitis. Ultimately, the patient was referred to a National Small Intestinal Transplant Centre for consideration for enterectomy and subsequent transplantation. We describe the difficulties encountered in managing this unique case and discuss the underlying aetiology.

Infliximab as long-term maintenance in steroid-resistant and recurrent sarcoidosis in a renal transplant with central nervous system involvement.

Sarcoidosis is a multisystemic, granulomatous disease of unknown aetiology, which commonly involves the lungs, skin and the eyes. Renal sarcoidosis is rare. Recurrent renal sarcoidosis leading to transplant graft failure in adults has not been reported. We report a single case of steroid-resistant sarcoid with recurrence in a renal transplant and the central nervous system that was managed with infliximab. We describe successful resolution of granulomas in the transplant kidney and stabilization of renal function with catastrophic central nervous system recurrence upon withdrawal of infliximab.

Enteric neuromuscular pathology update.

The recent development of consensus guidelines for the preparation and staining of tissues, the publication of the London Classification, and reviews of what is normal in the enteric neuromusculature have been significant steps forward in this field. Increased accessibility to full-thickness biopsies of the bowel wall facilitated by advances in laparoscopic surgery have also played a part in making the decision to ask for a tissue diagnosis easier. Better antibodies for immunohistochemistry and a better understanding of disease processes at work, such as those seen in filamin mutations, all help inform the range of information that can be gleaned from what is usually a very limited sample. Clinical phenotyping remains difficult in many patients, but the availability of specialist pathologic review and the standardization of staining between laboratories are leading to better defined histologic phenotypes, that inform, in turn, possible biological processes at work in these patients. In many instances, a diagnosis may come to light only after some time, and the retention of pathologic samples in paraffin wax, as is standard practice in most laboratories, is of great value in reassessing samples, often after many years, in the light of new advances. The highest quality information, and the best answer for the patient, is, as ever, achieved by close working relationships and excellent communication between clinicians and pathologists.

Inflammatory skin and bowel disease linked to ADAM17 deletion.

We performed genetic and immunohistochemical studies in a sister and brother with autosomal recessive neonatal inflammatory skin and bowel lesions. The girl died suddenly at 12 years of age from parvovirus B19-associated myocarditis; her brother had mild cardiomyopathy. We identified a loss-of-function mutation in ADAM17, which encodes a disintegrin and metalloproteinase 17 (also called tumor necrosis factor α [TNF-α]-converting enzyme, or TACE), as the probable cause of this syndrome. Peripheral-blood mononuclear cells (PBMCs) obtained from the brother at 17 years of age showed high levels of lipopolysaccharide-induced production of interleukin-1ß and interleukin-6 but impaired release of TNF-α. Despite repeated skin infections, this young man has led a relatively normal life. (Funded by Barts and the London Charity and the European Commission Seventh Framework Programme.).

The intracellular uptake of CD95 modified paclitaxel-loaded poly(lactic-co-glycolic acid) microparticles.

The CD95/CD95L receptor-ligand system is mainly recognised in the induction of apoptosis. However, it has also been shown that CD95L is over-expressed in many cancer types where it modulates immune-evasion and together with its receptor CD95 promotes tumour growth. Here, we show that CD95 surface modification of relatively large microparticles >0.5 µm in diameter, including those made from biodegradable polylactic-co-glycolic acid (PLGA), enhances intracellular uptake by a range of CD95L expressing cells in a process akin to phagocytosis. Using this approach we describe the intracellular uptake of microparticles and agent delivery in neurons, medulloblastoma, breast and ovarian cancer cells in vitro. CD95 modified paclitaxel-loaded PLGA microparticles are shown to be significantly more effective compared to conventional paclitaxel therapy (Taxol) at the same dose in subcutaneous medulloblastoma (∗∗∗P < 0.0001) and orthotopic ovarian cancer xenograft models where a >65-fold reduction in tumour bioluminescence was measured after treatment (∗P = 0.012). This drug delivery platform represents a new way of manipulating the normally advantageous tumour CD95L over-expression towards a therapeutic strategy. CD95 functionalised drug carriers could contribute to the improved function of cytotoxics in cancer, potentially increasing drug targeting and efficacy whilst reducing toxicity.

The London Classification of gastrointestinal neuromuscular pathology: report on behalf of the Gastro 2009 International Working Group.

OBJECTIVE: Guidelines on histopathological techniques and reporting for adult and paediatric gastrointestinal neuromuscular pathology have been produced recently by an international working group (IWG). These addressed the important but relatively neglected areas of histopathological practice of the general pathologist, including suction rectal biopsy and full-thickness intestinal tissue. Recommendations were presented for the indications, safe acquisition of tissue, histological techniques, reporting and referral of such histological material. DESIGN: Consensual processes undertaken by the IWG and following established guideline decision group methodologies. RESULTS AND CONCLUSION: This report presents a contemporary and structured classification of gastrointestinal neuromuscular pathology based on defined histopathological criteria derived from the existing guidelines. In recognition of its origins and first presentation in London at the World Congress of Gastroenterology 2009, this has been named 'The London Classification'. The implementation of this classification should allow some diagnostic standardisation, but should necessarily be viewed as a starting point for future modification as new data become available.