Citations

Abstract Background Mendelian randomization (MR) studies are susceptible to metadata errors (e.g. incorrect specification of the effect allele column) and other analytical issues that can introduce substantial bias into analyses. We developed a quality control (QC) pipeline for the Fatty Acids in Cancer Mendelian Randomization Collaboration (FAMRC) that can be used to identify and correct for such errors. Methods We collated summary association statistics from fatty acid and cancer genome-wide association studies (GWAS) and subjected the collated data to a comprehensive QC pipeline. We identified metadata errors through comparison of study-specific statistics to external reference data sets (the National Human Genome Research Institute-European Bioinformatics Institute GWAS catalogue and 1000 genome super populations) and other analytical issues through comparison of reported to expected genetic effect sizes. Comparisons were based on three sets of genetic variants: (i) GWAS hits for fatty acids, (ii) GWAS hits for cancer and (iii) a 1000 genomes reference set. Results We collated summary data from 6 fatty acid and 54 cancer GWAS. Metadata errors and analytical issues with the potential to introduce substantial bias were identified in seven studies (11.6%). After resolving metadata errors and analytical issues, we created a data set of 219 842 genetic associations with 90 cancer types, generated in analyses of 566 665 cancer cases and 1 622 374 controls. Conclusions In this large MR collaboration, 11.6% of included studies were affected by a substantial metadata error or analytical issue. By increasing the integrity of collated summary data prior to their analysis, our protocol can be used to increase the reliability of downstream MR analyses. Our pipeline is available to other researchers via the CheckSumStats package (https://github.com/MRCIEU/CheckSumStats).

AbstractObjectiveIn this observational study on a cohort of biopsy‐proven central nervous system demyelinating disease consistent with MS, we examined the relationship between early‐active demyelinating lesion immunopattern (IP) with subsequent clinical course, radiographic progression, and cognitive function.MethodsSeventy‐five patients had at least one early‐active lesion on biopsy and were pathologically classified into three immunopatterns based on published criteria. The median time from biopsy at follow‐up was 11 years, median age at biopsy ‐ 41, EDSS ‐ 4.0. At last follow‐up, the median age was 50, EDSS ‐ 3.0. Clinical examination, cognitive assessment (CogState battery), and 3‐Tesla‐MRI (MPRAGE/FLAIR/T2/DIR/PSIR/DTI) were obtained.ResultsIP‐I was identified in 14/75 (19%), IP‐II was identified in 41/75 (56%), and IP‐III was identified in 18/75 (25%) patients. Patients did not differ significantly by immunopattern in clinical measures at onset or last follow‐up. The proportions of disease courses after a median of 11 years were similar across immunopatterns, relapsing–remitting being most common (63%), followed by monophasic (32%). No differences in volumetric or DTI measures were found. CogState performance was similar for most tasks. A slight yet statistically significant difference was identified for episodic memory scores, with IP‐III patients recalling one word less on average.InterpretationIn this study, immunopathological heterogeneity of early‐active MS lesions identified at biopsy does not correlate with different long‐term clinical, neuroimaging or cognitive outcomes. This could be explained by the fact that while active white matter lesions are pathological substrates for relapses, MS progression is driven by mechanisms converging across immunopatterns, regardless of pathogenic mechanisms driving the acute demyelinated plaque.

Chronic kidney disease (CKD) progression involves morphological changes in the kidney, such as decreased length and thickness, with associated histopathological alterations. However, the relationship between morphological changes in the kidneys and glomerular filtration rate (GFR) has not been quantitatively and comprehensively evaluated. We evaluated the three-dimensional size and shape of the kidney using computed tomography (CT)-derived features in relation to kidney function. We included 257 patients aged ≥18 years who underwent non-contrast abdominal CT at the Inha University Hospital. The features were quantified using predefined algorithms in the pyRadiomics package after kidney segmentation. All features, except for flatness, significantly correlated with estimated GFR (eGFR). The surface-area-to-volume ratio (SVR) showed the strongest negative correlation (r = −0.75, p < 0.0001). Kidney size features, such as volume and diameter, showed moderate to high positive correlations; other morphological features showed low to moderate correlations. The calculated area under the receiver operating characteristic (ROC) curve (AUC) for different features ranged from 0.51 (for elongation) to 0.86 (for SVR) for different eGFR thresholds. Diabetes patients had weaker correlations between the studied features and eGFR and showed less bumpy surfaces in three-dimensional visualization. We identified alterations in the CKD kidney based on various three-dimensional shape and size features, with their potential diagnostic value.

Sonic hedgehog signaling regulates processes of embryonic development across multiple tissues, yet factors regulating context-specific Shh signaling remain poorly understood. Exome sequencing of families with polymicrogyria (disordered cortical folding) revealed multiple individuals with biallelic deleterious variants in TMEM161B , which encodes a multi-pass transmembrane protein of unknown function. Tmem161b null mice demonstrated holoprosencephaly, craniofacial midline defects, eye defects, and spinal cord patterning changes consistent with impaired Shh signaling, but were without limb defects, suggesting a CNS-specific role of Tmem161b. Tmem161b depletion impaired the response to Smoothened activation in vitro and disrupted cortical histogenesis in vivo in both mouse and ferret models, including leading to abnormal gyration in the ferret model. Tmem161b localizes non-exclusively to the primary cilium, and scanning electron microscopy revealed shortened, dysmorphic, and ballooned ventricular zone cilia in the Tmem161b null mouse, suggesting that the Shh-related phenotypes may reflect ciliary dysfunction. Our data identify TMEM161B as a regulator of cerebral cortical gyration, as involved in primary ciliary structure, as a regulator of Shh signaling, and further implicate Shh signaling in human gyral development.

Abstract Intronic G4C2 hexanucleotide repeat expansions (HRE) of C9orf72 are the most common cause of familial variants of frontotemporal dementia/amyotrophic lateral sclerosis (FTD/ALS). G4C2 HREs in C9orf72 undergo non-canonical repeat-associated translation, producing dipeptide repeat (DPR) proteins, with various deleterious impacts on cellular homeostasis. While five different DPRs are produced, poly(glycine-arginine) (GR) is amongst the most toxic and is the only DPR to accumulate in the associated clinically relevant anatomical locations of the brain. Previous work has demonstrated the profound effects of a poly(GR) model of C9orf72 FTD/ALS, including motor impairment, memory deficits, neurodegeneration, and neuroinflammation. Neuroinflammation is hypothesized to be a driving factor in the disease course; microglia activation is present prior to symptom onset and persists throughout the disease. Here, using an established mouse model of C9orf72 FTD/ALS we investigate the contributions of the nod-like receptor pyrin-containing 3 (NLRP3) inflammasome in the pathogenesis of FTD/ALS. We find that inflammasome-mediated neuroinflammation is increased with microglial activation, cleavage of caspase-1, production of IL-1β and upregulation of Cxcl10 in the brain of C9orf72 FTD/ALS mice. Excitingly, we find that genetic ablation of Nlrp3 significantly improved survival, protected behavioral deficits and prevented neurodegeneration suggesting a novel mechanism involving HRE-mediated induction of innate immunity. The findings provide experimental evidence of the integral role of HRE in inflammasome-mediated innate immunity in the C9orf72 variant of FTD/ALS pathogenesis and suggest the NLRP3 inflammasome as a therapeutic target.

Abstract Aims To investigate whether left arterial reservoir strain (LASr) could predict new-onset atrial fibrillation (NOAF) in patients with light-chain-type cardiac amyloidosis (ALCA). Methods and results This study enrolled 427 patients with CA from two tertiary centres between 2005 and 2019. LASr was measured using a vendor-independent analysis programme. The primary outcome was NOAF. A total of 287 patients with ALCA were included [median age 63.0 (56.0–70.0) years, 53.3% male]. The median LASr was 13.9% (10.5–20.8%). During the median follow-up of 0.85 years, AF occurred in 34 patients (11.8%). In the receiver operating characteristics curve analysis, the optimal cut-off of LASr for predicting NOAF was 14.4%. Patients with LASr ≤14.4% had a higher risk of NOAF than those with LASr &gt;14.4% (18.1% vs. 5.1%, P &lt; 0.010). In the multivariate analysis adjusting for confounding factors, including left arterial volume index and left ventricular global longitudinal strain (LV-GLS), higher LASr (%) was independently associated with lower risk for NOAF [adjusted hazard ratio (aHR): 0.936, 95% confidence interval (95% CI): 0.879–0.997, P = 0.039]. Furthermore, LASr ≤14.4% was an independent predictor for NOAF (aHR: 3.370, 95% CI: 1.337–8.492, P = 0.010). This remained true after accounting for all-cause death as a competing risk. Compared with Model 1 (LV-GLS) and Model 2 (LV-GLS plus LAVI), Model 3, including LASr showed a better reclassification ability for predicting NOAF (net reclassification index = 0.735, P &lt; 0.001 compared with Model 1; net reclassification index = 0.514, P = 0.003 compared with Model 2). Conclusion LASr was an independent predictor of NOAF in patients with ALCA.

AbstractAimsIntraoperative defibrillation testing (DT) during implant or replacement of implantable cardioverter-defibrillators (ICDs) has been a matter of debate for many years. This debate was put to rest by the Simple and Nordic ICD trials, and the practice of testing during new implantations has essentially been almost abandoned. Old registries demonstrated an increased incidence of significant findings in DT during replacements. The aim of the present study was to evaluate frequency of significant findings and safety of DT in subjects undergoing device replacement.Methods and resultsA prospective observational multi-centre study included consecutive patients undergoing ICD generator replacement. The primary outcome was a failure to terminate induced ventricular fibrillation (VF) with a single shock 10 J below the maximal capacity of the device. Secondary outcomes included complications of DT. Patients were followed-up at 1- and 6-months post-procedure. A total of 92 patients were eligible, and consented to the study, of which 84 underwent DT during battery replacement. The median age was 68 years and 79.8% were males. Induction of VF was successful in 84 patients as was a successful conversion on the first attempt in all. There were no procedure-related complications. During follow up one patient had two appropriate ICD shock events. In four patients, ICD programming was changed. None suffered inappropriate shock. There was no evidence of lead malfunction. Two deaths occurred, none of which was related to arrhythmia.ConclusionThe present study found DT was not associated with complications in patients undergoing ICD generator replacement but produced no clinically important information.

Abstract Glioblastoma is the most common and lethal primary brain tumor in adults, with a median survival less than 15 months despite current standard of care. Oncolytic immunovirotherapies (OVs) have shown promise in early clinical trials. OVs are engineered to specifically target cancer cells, trigger autophagic programmed cell death, and release tumor antigens in the context of T-cell activating cytokines. Cellular communication network factor 1 (CCN1) is an extracellular matrix protein expressed in 70% of glioblastomas that has been shown to drastically reduce OV efficacy, particularly herpes simplex virus type 1 (HSV-1). Our objectives were to decode protein-protein interaction (PPI) networks activated by CCN1, identify critical nodes in resistance networks, and use this analysis to design OVs that overcome CCN1-mediated resistance. We used NetDecoder to elucidate phenotype-specific PPI subnetworks in LN229 human glioblastoma cells with tetracycline-inducible CCN1 expression. Publicly available microarray data on CCN1-induced and control samples established differentially expressed genes, which served as sources in our PPI network to derive prioritized context-specific subnetworks. We found that 11 source genes collaborate via 39 deep nodes to confer OV resistance to CCN1-expressing glioblastomas. Of these, a router (IKBKE) and a sink (YBX1) have been previously implicated in glioblastoma pathogenesis. We conclude that autophagy regulator HSP90AA1, a critical node, may be targeted to improve OV efficacy in CCN1-expressing glioblastomas. Furthermore, WebGestalt overrepresentation analysis of subnetwork nodes suggests that oncolytic adenovirus may be more effective than HSV-1 as a synthetic biology chassis.

Abstract Background Although perceived barriers to applying to dermatology have been researched among medical students, there remains a dearth of literature dedicated to understanding perceptions that medical students have of the field of dermatology and dermatologists. Methods A review of the literature in Embase, Pubmed, Scopus, Web of Science, and ScienceDirect were carried out to identify articles and abstracts between 2016 and 2021 relating to medical student perceptions of the field of dermatology. Peer-reviewed English studies measuring attitudes/level of interest in dermatology or other specialities, understanding of dermatologic topics, procedures, and/or scope of practice were included. Duplicate studies and conference abstracts were excluded. All publications were screened using the PRISMA-Sc guidelines. Findings were summarised and tabulated accordingly. Results A total of nine articles met inclusion criteria and eight are included in this review since one was not accessible online. Notable findings include non-US medical students perceiving dermatology as monotonous, stigmatized, unfamiliar, and difficult to access with a misunderstanding of the diversity and severity of the conditions dermatologists treat. No data on US medical student perceptions was found. Perceptions were found to be influential in career planning: medical students may reject specialities after exposure to negative comments on the field. Factors attracting students to dermatology include the appeal of being a dermatologist, media portrayal, and dermatologists' influence on patients' lives. Completion of dermatology-related activities improved medical student interest, comfort, and understanding of the field. Early dermatology exposure in US undergraduate premedical students led to heightened interest in the field, more confidence in ability to find dermatology mentors, and increased perception that dermatology serves the needs of underserved communities. Conclusions This review demonstrates the need to further investigate medical student perceptions of dermatology, particularly in the United States. Perceptions of medical specialities can impact medical student career choices. Understanding which misconceptions may be preventing students from exploring dermatology can inform efforts towards improving diversity, equity, and inclusion: translating to an equitable match and improving patient outcomes. Limitations include exclusion of articles published before 2016, geographic variability in studies, and limited data on evolving student perceptions over time.