Sirolimus use in patients with subglottic stenosis in the context of granulomatosis with polyangiitis (GPA), suspected GPA, and immunoglobulin G4-related disease

OBJECTIVE: Subglottic stenosis (SGS) is a severe, life-threatening disease found in immune-mediated diseases such as granulomatosis with polyangiitis (GPA) and in rare cases of immunoglobulin G4 (IgG4)-related disease. It can result in persistent airway compromise due to the fibrotic response following inflammation. Standard management involves repeated endoscopic interventions to dilate the airway, and tracheostomy is occasionally required. In addition, immunosuppression remains a cornerstone of therapy aimed at controlling the underlying inflammatory disease; however, cumulative dosing leads to significant adverse effects. We present five cases of predominantly anti-neutrophil cytoplasmic antibody-negative GPA and a case of IgG4-related disease with SGS, in whom we evaluated the long-term utility of sirolimus, which has beneficial anti-proliferative and fibrotic effects, in the management of their disease. METHOD: We conducted a retrospective review of a cohort of patients with SGS at a tertiary vasculitis unit. These patients were treated with sirolimus, in addition to conventional medical and endoscopic treatment. Clinical symptoms, frequency and time to endoscopic intervention pre- and post-treatment, additional rescue therapy, and any adverse effects were recorded and analysed. RESULTS: Six patients were treated with sirolimus and followed for up to 9 years; two discontinued the drug owing to adverse effects, early on. In the remaining four patients, glucocorticoids were withdrawn, and the frequency of endoscopic intervention was reduced. One patient on sirolimus required rituximab therapy for disease flare. CONCLUSION: Sirolimus may be a therapeutic option for some patients with severe SGS, allowing steroid withdrawal and resulting in a positive adverse effect profile

Towards NHS Zero: greener gastroenterology and the impact of virtual clinics on carbon emissions and patient outcomes. A multisite, observational, cross-sectional study

OBJECTIVE: The National Health Service (NHS) produces more carbon emissions than any public sector organisation in England. In 2020, it became the first health service worldwide to commit to becoming carbon net zero, the same year as the COVID-19 pandemic forced healthcare systems globally to rapidly adapt service delivery. As part of this, outpatient appointments became largely remote. Although the environmental benefit of this change may seem intuitive the impact on patient outcomes must remain a priority. Previous studies have evaluated the impact of telemedicine on emission reduction and patient outcomes but never before in the gastroenterology outpatient setting. METHOD: 2140 appointments from general gastroenterology clinics across 11 Trusts were retrospectively analysed prior to and during the pandemic. 100 consecutive appointments during two periods of time, from 1 June 2019 (prepandemic) to 1 June 2020 (during the pandemic), were used. Patients were telephoned to confirm the mode of transport used to attend their appointment and electronic patient records reviewed to assess did-not-attend (DNA) rates, 90-day admission rates and 90-day mortality rates. RESULTS: Remote consultations greatly reduced the carbon emissions associated with each appointment. Although more patients DNA their remote consultations and doctors more frequently requested follow-up blood tests when reviewing patients face-to-face, there was no significant difference in patient 90-day admissions or mortality when consultations were remote. CONCLUSION: Remote consultations greatly reduced the carbon emissions associated with each appointment. Although more patients DNA their remote consultations and doctors more frequently requested follow-up blood tests when reviewing patients face-to-face, there was no significant difference in patient 90-day admissions or mortality when consultations were remote

Sparse, decorrelated odor coding in the mushroom body enhances learned odor discrimination

Sparse coding may be a general strategy of neural systems for augmenting memory capacity. In Drosophila melanogaster, sparse odor coding by the Kenyon cells of the mushroom body is thought to generate a large number of precisely addressable locations for the storage of odor-specific memories. However, it remains untested how sparse coding relates to behavioral performance. Here we demonstrate that sparseness is controlled by a negative feedback circuit between Kenyon cells and the GABAergic anterior paired lateral (APL) neuron. Systematic activation and blockade of each leg of this feedback circuit showed that Kenyon cells activated APL and APL inhibited Kenyon cells. Disrupting the Kenyon cell–APL feedback loop decreased the sparseness of Kenyon cell odor responses, increased inter-odor correlations and prevented flies from learning to discriminate similar, but not dissimilar, odors. These results suggest that feedback inhibition suppresses Kenyon cell activity to maintain sparse, decorrelated odor coding and thus the odor specificity of memories

Loss of Caveolin-1 Accelerates Neurodegeneration and Aging

The aged brain exhibits a loss in gray matter and a decrease in spines and synaptic densities that may represent a sequela for neurodegenerative diseases such as Alzheimer's. Membrane/lipid rafts (MLR), discrete regions of the plasmalemma enriched in cholesterol, glycosphingolipids, and sphingomyelin, are essential for the development and stabilization of synapses. Caveolin-1 (Cav-1), a cholesterol binding protein organizes synaptic signaling components within MLR. It is unknown whether loss of synapses is dependent on an age-related loss of Cav-1 expression and whether this has implications for neurodegenerative diseases such as Alzheimer's disease.We analyzed brains from young (Yg, 3-6 months), middle age (Md, 12 months), aged (Ag, >18 months), and young Cav-1 KO mice and show that localization of PSD-95, NR2A, NR2B, TrkBR, AMPAR, and Cav-1 to MLR is decreased in aged hippocampi. Young Cav-1 KO mice showed signs of premature neuronal aging and degeneration. Hippocampi synaptosomes from Cav-1 KO mice showed reduced PSD-95, NR2A, NR2B, and Cav-1, an inability to be protected against cerebral ischemia-reperfusion injury compared to young WT mice, increased Aβ, P-Tau, and astrogliosis, decreased cerebrovascular volume compared to young WT mice. As with aged hippocampi, Cav-1 KO brains showed significantly reduced synapses. Neuron-targeted re-expression of Cav-1 in Cav-1 KO neurons in vitro decreased Aβ expression.Therefore, Cav-1 represents a novel control point for healthy neuronal aging and loss of Cav-1 represents a non-mutational model for Alzheimer's disease

Long-term follow-up of the use of maintenance antibiotic therapy for chronic antibiotic-dependent pouchitis

Objective: Restorative proctolectomy is considered the procedure of choice in patients with ulcerative colitis who have failed medical therapy. Chronic pouchitis occurs in 10%-15% of patients, which often require long-term antibiotics to alleviate symptoms. Safety and efficacy of long-term maintenance antibiotics for chronic pouchitis has yet to be established. We aimed to assess the long-term safety and efficacy of maintenance antibiotic therapy for chronic pouchitis. Design: This was an observational study. We followed up patients who were diagnosed with chronic antibiotic-dependent pouchitis. Setting: Data were collected from our single specialist pouch centre. Patients: Patients with chronic antibiotic-dependent pouchitis who had been maintained on antibiotics continuously for at least 1 year with a least one follow-up visit. Main outcome measure: Development of pouch failure defined by the need for an ileostomy, patient-reported side effects of antibiotics and development of antibiotic resistance found on stool coliform testing. Results: Long-term use of antibiotics achieve remission in 21% of patients over a median follow-up of 102 (range 9-125). Pouch failure in association with chronic pouchitis after a median follow-up of 8.5 years occurred in 18%. Side effects of long-term antibiotic use occurred in 28% of patients, with resistance to antibiotics from at least one stool sample occurring in 78% patients. Conclusions: Although the use of antibiotics in chronic pouchitis may be justified, the use of long-term antibiotics must be weighed against potential complications associated with pouchitis and antibiotics

IgG4-related disease in a multi-ethnic community: Clinical characteristics and association with malignancy

Background Immunoglobulin-G4-related disease (IgG4-RD) is a recently recognised fibro-inflammatory condition that can affect multiple organs. Despite growing interest in this condition, the natural history and management of IgG4-RD remain poorly understood. Aim To describe the clinical characteristics, treatment and outcomes of IgG4-RD in a multi-ethnic UK cohort, and investigate its possible association with malignancy. Design Retrospective analysis of case-note and electronic data. Methods Cases were identified from sub-specialty cohorts and a systematic search of an NHS trust histopathology database using ‘IgG4’ or ‘inflammatory pseudotumour’ as search terms. Electronic records, imaging and histopathology reports were reviewed. Results 66 identified cases of IgG4-RD showed a similar multi-ethnic spread to the local population of North West London. The median age was 59 years and 71% of patients were male. Presenting symptoms relating to mass effect of a lesion were present in 48% of cases and the mean number of organs involved was 2.4. 10 patients had reported malignancies with 6 of these being haematological. 83% of those treated with steroids had good initial response, however 50% had relapsing-remitting disease. Rituximab was administered in 11 cases and all achieved an initial serological response. Despite this, 7 patients subsequently relapsed after a mean duration of 11 months and 4 progressed despite treatment. Conclusions We report a large UK-based cohort of IgG4-RD that shows no clear ethnic predisposition and a wide range of affected organs. We discuss the use of serum IgG4 concentrations as a disease marker in IgG4-RD, the association with malignant disease and outcomes according to differing treatment regimens

The neurotrophin receptor p75(NTR) : novel functions and implications for diseases of the nervous system

Neurotrophins have long been known to promote the survival and differentiation of vertebrate neurons. However, these growth factors can also induce cell death through the p75 neurotrophin receptor (p75(NTR)), a member of the tumor necrosis factor receptor superfamily. Consistent with a function in controlling the survival and process formation of neurons, p75(NTR) is mainly expressed during early neuronal development. In the adult, p75(NTR) is re-expressed in various pathological conditions, including epilepsy, axotomy and neurodegeneration. Potentially toxic peptides, including the amyloid beta- (Abeta-) peptide that accumulates in Alzheimer's disease, are ligands for p75(NTR). Recent work also implicates p75(NTR) in the regulation of both synaptic transmission and axonal elongation. It associates with the Nogo receptor, a binding protein for axonal growth inhibitors, and appears to be the transducing subunit of this receptor complex