12-Lipoxygenase inhibition suppresses islet immune and inflammatory responses and delays autoimmune diabetes in human gene replacement mice.

Type 1 diabetes (T1D) is characterized by the autoimmune destruction of insulin-producing ß cells and involves an interplay between ß cells and cells of the innate and adaptive immune systems. We investigated the therapeutic potential of targeting 12-lipoxygenase (12-LOX), an enzyme implicated in inflammatory pathways in ß cells and macrophages, using a mouse model in which the endogenous mouse Alox15 gene is replaced by the human ALOX12 gene. Our findings demonstrate that VLX-1005, a potent 12-LOX inhibitor, effectively delays the onset of autoimmune diabetes in human gene replacement non-obese diabetic (NOD) mice. By spatial proteomics analysis, VLX-1005 treatment resulted in marked reductions in infiltrating T and B cells and macrophages with accompanying increases in immune checkpoint molecules PD-L1 and PD-1, suggesting a shift towards an immune-suppressive microenvironment. RNA sequencing analysis of isolated islets from inhibitor-treated mice revealed significant alteration of cytokine-responsive pathways. RNA sequencing of polarized proinflammatory macrophages showed that VLX-1005 significantly reduced the interferon response. Our studies demonstrate that the ALOX12 human replacement gene mouse provides a platform for the preclinical evaluation of LOX inhibitors and supports VLX-1005 as an inhibitor of human 12-LOX that engages the enzymatic target and alters the inflammatory phenotypes of islets and macrophages to promote the delay of autoimmune diabetes.

Inhibition of the Eukaryotic Initiation Factor-2-α Kinase PERK Decreases Risk of Autoimmune Diabetes in Mice.

Preventing the onset of autoimmune type 1 diabetes (T1D) is feasible through pharmacological interventions that target molecular stress-responsive mechanisms. Cellular stresses, such as nutrient deficiency, viral infection, or unfolded proteins, trigger the integrated stress response (ISR), which curtails protein synthesis by phosphorylating eIF2α. In T1D, maladaptive unfolded protein response (UPR) in insulin-producing ß cells renders these cells susceptible to autoimmunity. We show that inhibition of the eIF2α kinase PERK, a common component of the UPR and ISR, reverses the mRNA translation block in stressed human islets and delays the onset of diabetes, reduces islet inflammation, and preserves ß cell mass in T1D-susceptible mice. Single-cell RNA sequencing of islets from PERK-inhibited mice shows reductions in the UPR and PERK signaling pathways and alterations in antigen processing and presentation pathways in ß cells. Spatial proteomics of islets from these mice shows an increase in the immune checkpoint protein PD-L1 in ß cells. Golgi membrane protein 1, whose levels increase following PERK inhibition in human islets and EndoC-ßH1 human ß cells, interacts with and stabilizes PD-L1. Collectively, our studies show that PERK activity enhances ß cell immunogenicity, and inhibition of PERK may offer a strategy to prevent or delay the development of T1D.

Inhibition of the eukaryotic initiation factor-2-α kinase PERK decreases risk of autoimmune diabetes in mice.

Preventing the onset of autoimmune type 1 diabetes (T1D) is feasible through pharmacological interventions that target molecular stress-responsive mechanisms. Cellular stresses, such as nutrient deficiency, viral infection, or unfolded proteins, trigger the integrated stress response (ISR), which curtails protein synthesis by phosphorylating eIF2α. In T1D, maladaptive unfolded protein response (UPR) in insulin-producing beta cells renders these cells susceptible to autoimmunity. We found that inhibition of the eIF2α kinase PERK, a common component of the UPR and ISR, reversed the mRNA translation block in stressed human islets and delayed the onset of diabetes, reduced islet inflammation, and preserved ß cell mass in T1D-susceptible mice. Single-cell RNA sequencing of islets from PERK-inhibited mice showed reductions in the UPR and PERK signaling pathways and alterations in antigen processing and presentation pathways in ß cells. Spatial proteomics of islets from these mice showed an increase in the immune checkpoint protein PD-L1 in ß cells. Golgi membrane protein 1, whose levels increased following PERK inhibition in human islets and EndoC-ßH1 human ß cells, interacted with and stabilized PD-L1. Collectively, our studies show that PERK activity enhances ß cell immunogenicity, and inhibition of PERK may offer a strategy to prevent or delay the development of T1D.

Acceptability of a Future HIV Vaccine: A Rapid Scoping Review.

BACKGROUND: A HIV vaccine is not available yet, but perceptions of HIV vaccines will be important to explore before their roll-out for effective vaccine promotion. This article presents the findings of a rapid scoping review of the literature to identify individual, social, and vaccine-related factors associated with the acceptability of a future HIV vaccine. METHODS: We searched 5 databases (Medline OVID, Embase, PsycINFO, Web of Science, and Cochrane) using relevant keywords and Medical Subject Headings. All articles, regardless of study design, publication year, and geographic location, were included if they examined HIV vaccine acceptability and its underlying factors. RESULTS: We retrieved 2386 unique articles, of which 76 were included in the final review. Perceived benefits (34.2%) and perceived susceptibility (25.0%) were primary individual factors of HIV vaccine acceptability. Misinformation (17.1%) and distrust (22.4%) regarding future HIV vaccines, HIV stigma (30.3%), and social support (10.5%) were social factors of HIV vaccine acceptability. Vaccine efficacy (42.1%), cost (28.9%), and side effects (67.1%) were common vaccine characteristics influencing HIV vaccine acceptability. Altruism (10.5%) and risk compensation (26.3%) were also key factors. CONCLUSIONS: Our analyses revealed that skeptical beliefs, negative perceptions, and misconceptions about HIV vaccines are real barriers to their acceptability. To alleviate HIV vaccine hesitancy and address trust concerns, strategic vaccine communication should be disseminated by trustworthy sources. Messages should impart accurate vaccine information and emphasize both individual and social benefits of HIV vaccination, as well as leverage social support in increasing willingness to get a future HIV vaccine.

Discordant Effects of Polyamine Depletion by DENSpm and DFMO on ß-cell Cytokine Stress and Diabetes Outcomes in Mice.

Type 1 diabetes (T1D) is an autoimmune disease leading to dysfunction and loss of insulin-secreting ß cells. In ß cells, polyamines have been implicated in causing cellular stress and dysfunction. An inhibitor of polyamine biosynthesis, difluoromethylornithine (DFMO), has been shown to delay T1D in mouse models and preserve ß-cell function in humans with recent-onset T1D. Another small molecule, N1,N11-diethylnorspermine (DENSpm), both inhibits polyamine biosynthesis and accelerates polyamine metabolism and is being tested for efficacy in cancer clinical trials. In this study, we show that DENSpm depletes intracellular polyamines as effectively as DFMO in mouse ß cells. RNA-sequencing analysis, however, suggests that the cellular responses to DENSpm and DFMO differ, with both showing effects on cellular proliferation but the latter showing additional effects on mRNA translation and protein-folding pathways. In the low-dose streptozotocin-induced mouse model of T1D, DENSpm, unlike DFMO, did not prevent or delay diabetes outcomes but did result in improvements in glucose tolerance and reductions in islet oxidative stress. In nonobese diabetic (NOD) mice, short-term DENSpm administration resulted in a slight reduction in insulitis and proinflammatory Th1 cells in the pancreatic lymph nodes. Longer term treatment resulted in a dose-dependent increase in mortality. Notwithstanding the efficacy of both DFMO and DENSpm in reducing potentially toxic polyamine levels in ß cells, our results highlight the discordant T1D outcomes that result from differing mechanisms of polyamine depletion and, more importantly, that toxic effects of DENSpm may limit its utility in T1D treatment.

Generalizable pipeline for constructing HIV risk prediction models across electronic health record systems.

OBJECTIVE: The HIV epidemic remains a significant public health issue in the United States. HIV risk prediction models could be beneficial for reducing HIV transmission by helping clinicians identify patients at high risk for infection and refer them for testing. This would facilitate initiation on treatment for those unaware of their status and pre-exposure prophylaxis for those uninfected but at high risk. Existing HIV risk prediction algorithms rely on manual construction of features and are limited in their application across diverse electronic health record systems. Furthermore, the accuracy of these models in predicting HIV in females has thus far been limited. MATERIALS AND METHODS: We devised a pipeline for automatic construction of prediction models based on automatic feature engineering to predict HIV risk and tested our pipeline on a local electronic health records system and a national claims data. We also compared the performance of general models to female-specific models. RESULTS: Our models obtain similarly good performance on both health record datasets despite difference in represented populations and data availability (AUC = 0.87). Furthermore, our general models obtain good performance on females but are also improved by constructing female-specific models (AUC between 0.81 and 0.86 across datasets). DISCUSSION AND CONCLUSIONS: We demonstrated that flexible construction of prediction models performs well on HIV risk prediction across diverse health records systems and perform as well in predicting HIV risk in females, making deployment of such models into existing health care systems tangible.

Impact of routine urine cultures on antibiotic usage in those undergoing a routine annual spinal cord injury evaluation.

OBJECTIVE: The Veterans Health Administration (VHA), the largest single provider of spinal cord injury and disorder (SCI/D) care in the United States, currently mandates that every patient receives a screening urine culture during the annual evaluation, a yearly comprehensive history and physical examination. This testing has shown in a small subset of patients to overidentify asymptomatic bacteriuria that is then inappropriately treated with antibiotics. The objective of the current analysis was to assess the association of the annual evaluation on urine testing and antibiotic treatment in a national sample of Veterans with SCI/D. DESIGN/METHOD: A retrospective cohort study using national VHA electronic health record data of Veterans with SCI/D seen between October 1, 2017-September 30, 2019 for their annual evaluation. RESULTS: There were 9447 Veterans with SCI/D who received an annual evaluation; 5088 (54%) had a urine culture obtained. 2910 cultures (57%) were positive; E. coli was the most common organism obtained (12.9% of total urine cultures). Of the patients with positive urine cultures, 386 were prescribed antibiotics within the 7 days after that encounter (13%); of the patients with negative cultures (n = 2178), 121 (6%) were prescribed antibiotics; thus, a positive urine culture was a significant driver of antibiotic use (p < 0.001). CONCLUSION: The urine cultures ordered at the annual exam are often followed by antibiotics; this practice may be an important target for antibiotic stewardship programs in SCI.

Non-Alcoholic Fatty Liver Disease: Translating Disease Mechanisms into Therapeutics Using Animal Models.

Nonalcoholic fatty liver disease (NAFLD) is a range of pathologies arising from fat accumulation in the liver in the absence of excess alcohol use or other causes of liver disease. Its complications include cirrhosis and liver failure, hepatocellular carcinoma, and eventual death. NAFLD is the most common cause of liver disease globally and is estimated to affect nearly one-third of individuals in the United States. Despite knowledge that the incidence and prevalence of NAFLD are increasing, the pathophysiology of the disease and its progression to cirrhosis remain insufficiently understood. The molecular pathogenesis of NAFLD involves insulin resistance, inflammation, oxidative stress, and endoplasmic reticulum stress. Better insight into these molecular pathways would allow for therapies that target specific stages of NAFLD. Preclinical animal models have aided in defining these mechanisms and have served as platforms for screening and testing of potential therapeutic approaches. In this review, we will discuss the cellular and molecular mechanisms thought to contribute to NAFLD, with a focus on the role of animal models in elucidating these mechanisms and in developing therapies.

Epidemiology of Cancer-Associated Venous Thromboembolism in Patients With Solid and Hematologic Neoplasms in the Veterans Affairs Health Care System.

Importance: Identifying changes in epidemiologic patterns of the incidence and risk of cancer-associated thrombosis (CAT), particularly with evolving cancer-directed therapy, is essential for risk stratification. Objective: To assess the incidence of CAT over time and to determine pertinent patient-specific, cancer-specific, and treatment-specific factors associated with its risk. Design, Setting, and Participants: This longitudinal, retrospective cohort study was conducted from 2006 to 2021. Duration of follow-up was from the date of diagnosis until first venous thromboembolism (VTE) event, death, loss of follow-up (defined as a 90-day gap without clinical encounters), or administrative censoring on April 1, 2022. The study took place within the US Department of Veterans Affairs national health care system. Patients with newly diagnosed invasive solid tumors and hematologic neoplasms were included in the study. Data were analyzed from December 2022 to February 2023. Exposure: Newly diagnosed invasive solid tumors and hematologic neoplasms. Main Outcomes: Incidence of VTE was assessed using a combination of International Classification of Diseases, Ninth Revision, Clinical Modification and International Statistical Classification of Diseases, Tenth Revision, Clinical Modification and natural language processing confirmed outcomes. Cumulative incidence competing risk functions were used to estimate incidence of CAT. Multivariable Cox regression models were built to assess the association of baseline variables with CAT. Pertinent patient variables included demographics, region, rurality, area deprivation index, National Cancer Institute comorbidity index, cancer type, staging, first-line systemic treatment within 3 months (time-varying covariate), and other factors that could be associated with the risk of VTE. Results: A total of 434 203 patients (420 244 men [96.8%]; median [IQR] age, 67 [62-74] years; 7414 Asian or Pacific Islander patients [1.7%]; 20 193 Hispanic patients [4.7%]; 89 371 non-Hispanic Black patients [20.6%]; 313 157 non-Hispanic White patients [72.1%]) met the inclusion criteria. Overall incidence of CAT at 12 months was 4.5%, with yearly trends ranging stably from 4.2% to 4.7%. The risk of VTE was associated with cancer type and stage. In addition to confirming well-known risk distribution among patients with solid tumors, a higher risk of VTE was observed among patients with aggressive lymphoid neoplasms compared with patients with indolent lymphoid or myeloid hematologic neoplasms. Compared with no treatment, patients receiving first-line chemotherapy (hazard ratio [HR], 1.44; 95% CI, 1.40-1.49) and immune checkpoint inhibitors (HR, 1.49; 95% CI, 1.22-1.82) had a higher adjusted relative risk than patients receiving targeted therapy (HR, 1.21; 95% CI, 1.13-1.30) or endocrine therapy (HR, 1.20; 95% CI, 1.12-1.28). Finally, adjusted VTE risk was significantly higher among Non-Hispanic Black patients (HR, 1.23; 95% CI, 1.19-1.27) and significantly lower in Asian or Pacific Islander patients (HR, 0.84; 95% CI, 0.76-0.93) compared with Non-Hispanic White patients. Conclusions and Relevance: In this cohort study of patients with cancer, a high incidence of VTE was observed, with yearly trends that remained stable over the 16-year study period. Both novel and known factors associated with the risk of CAT were identified, providing valuable and applicable insights in this current treatment landscape.

Venous thromboembolism risk in cancer patients receiving first-line immune checkpoint inhibitor versus chemotherapy.

It remains unclear if immune checkpoint inhibitor (ICI) therapy is associated with higher rate of venous thromboembolism (VTE) compared with cytotoxic chemotherapy (chemo) in patients with comparable cancer type, staging, and comorbidities. Using the national Veterans Affairs healthcare system database from 2016 to 2021, we performed a propensity score (PS)-weighted retrospective cohort study to compare the incidence of VTE in patients with selected stage III/IV cancer receiving first-line ICI versus chemo. The PS model utilized overlap weights to balance age, sex, race, treatment year, VTE history, paralysis/immobilization, prolonged hospitalization, cancer type, staging, time between diagnosis and treatment, and National Cancer Institute comorbidity index. Weighted Cox regressions with robust standard error were used to assess the hazard ratio (HR) and 95% confidence interval (CI). We found that among comparable advanced cancers, first-line ICI (n = 1823) and first-line chemo (n = 6345) had similar rates of VTE (8.49% for ICI and 8.36% for chemo at 6 months). The weighted HR was 1.06 (95% CI 0.88-1.26) for ICI versus chemo. In a subgroup analysis restricted to lung cancers, first-line ICI/chemo (n = 828), ICI monotherapy (n = 428), and chemo monotherapy (n = 4371) had similar rates of VTE (9.60% for ICI/chemo, 10.04% for ICI, and 8.91% for chemo at 6 months). The weighted HR was 1.05 (95% CI 0.77-1.42) for ICI versus chemo, and 1.08 (95% CI 0.83-1.42) for ICI/chemo versus chemo. In conclusion, ICI as a systemic therapy has a similarly elevated risk as cytotoxic chemo for VTE occurrence in cancer patients. This finding can inform future prospective studies exploring thromboprophylaxis strategies.

Derivation and Validation of a Clinical Risk Assessment Model for Cancer-Associated Thrombosis in Two Unique US Health Care Systems.

PURPOSE: Venous thromboembolism (VTE), especially pulmonary embolism (PE) and lower extremity deep vein thrombosis (LE-DVT), is a serious and potentially preventable complication for patients with cancer undergoing systemic therapy. METHODS: Using retrospective data from patients diagnosed with incident cancer from 2011-2020, we derived a parsimonious risk assessment model (RAM) using least absolute shrinkage and selection operator regression from the Harris Health System (HHS, n = 9,769) and externally validated it using the Veterans Affairs (VA) health care system (n = 79,517). Bootstrapped c statistics and calibration curves were used to assess external model discrimination and fit. Dichotomized risk strata using integer scores were created and compared against the Khorana score (KS). RESULTS: Incident VTE and PE/LE-DVT at 6 months occurred in 590 (6.2%) and 437 (4.6%) patients in HHS and 4,027 (5.1%) and 3,331 (4.2%) patients in the VA health care system. Assessed at the time of systemic therapy initiation, the new RAM included components of the KS with the modified cancer subtype, cancer staging, systemic therapy class, history of VTE, history of paralysis/immobility, recent hospitalization, and Asian/Pacific Islander race. The c statistic was 0.71 in HHS and 0.68 in the VA health care system (compared with 0.65 and 0.60, respectively, for KS). Furthermore, the new RAM appropriately reclassified 28% of patients and increased the proportion of VTEs in the high-risk group from 37% to 68% in the validation data set. CONCLUSION: The novel RAM stratified patients with cancer into a high-risk group with 8%-10% cumulative incidence of VTE and 7% PE/LE-DVT at 6 months (v 3% and 2%, respectively, in the low-risk group). The model had improved performance over the original KS and doubled the number of VTE events in the high-risk stratum. We encourage additional external validation from prospective studies.[Media: see text].

Protocol to isolate immune cells from mouse pancreatic lymph nodes and whole pancreas for mass cytometric analyses.

Investigating the immune attack on ß cells is critical to understanding autoimmune diabetes. Here, we present a protocol to isolate immune cells from mouse pancreatic lymph nodes and whole pancreas, followed by mass cytometric analyses. This protocol can be used to analyze subsets of innate and adaptive immune cells that play critical roles in autoimmune diabetes, with as few as 5 × 105 cells. This protocol can also be adapted to study resident immune cells from other tissues. For complete details on the use and execution of this protocol, please refer to Piñeros et al. (2022).1.

Stress and human health in diabetes: A report from the 19th Chicago Biomedical Consortium symposium.

Stress and diabetes coexist in a vicious cycle. Different types of stress lead to diabetes, while diabetes itself is a major life stressor. This was the focus of the Chicago Biomedical Consortium's 19th annual symposium, "Stress and Human Health: Diabetes," in November 2022. There, researchers primarily from the Chicago area met to explore how different sources of stress - from the cells to the community - impact diabetes outcomes. Presenters discussed the consequences of stress arising from mutant proteins, obesity, sleep disturbances, environmental pollutants, COVID-19, and racial and socioeconomic disparities. This symposium showcased the latest diabetes research and highlighted promising new treatment approaches for mitigating stress in diabetes.

Interobserver Variability and Challenges in Intraoperative Frozen Section Evaluation of Pancreatic Margins in Pancreatectomy Specimens.

OBJECTIVE: Frozen-section evaluation of the pancreatic margin is challenging. We aimed to determine interobserver variability among gastrointestinal pathologists for the assessment of frozen sections of pancreatic margins with marked chronic pancreatitis and to determine the challenging histological features in discrepant cases. METHODS: We identified 45 patients who underwent pancreas resection for pancreatic ductal adenocarcinoma and showed marked chronic pancreatitis at pancreatic margin. Deidentified first levels of frozen-sections of the pancreatic margins from all cases were independently reviewed by 5 experienced gastrointestinal pathologists for the presence of carcinoma and/or high-grade dysplasia. RESULTS: Interobserver agreement among pathologists was calculated as kappa coefficients ([Formula: see text]). A consensus diagnosis for discordant cases was obtained after group review and discussion. Interobserver agreement for adenocarcinoma diagnosis was 87%, and there was "substantial agreement" (Fleiss [Formula: see text]=0.78, P<0.01) and "almost perfect agreement" (Brennan-Prediger [Formula: see text]=0.86, P<0.01). Using the final diagnosis based on frozen and permanent sections as the gold standard and the concordant read of at least 3 of 5 pathologists for comparison, the diagnosis of adenocarcinoma was made in frozen-sections of pancreas margins, with accuracy 98%, sensitivity 83%, specificity 100%, negative predictive value 97%, positive predictive value 100%, false negative rate 9%, and false positive rate 0%. CONCLUSIONS: We showed excellent interobserver agreement among gastrointestinal pathologists for diagnosis of adenocarcinoma on frozen sections of pancreatic margins with marked chronic pancreatitis. Missed adenocarcinoma at the margin was mainly caused by freezing or cautery artifacts or by overlooking a tiny focus of perineural invasion in a background of marked chronic pancreatitis. The evaluation of deeper levels led to perfect agreement.

Multidisciplinary Postoperative Validation of 18F-FDG PET/CT Scan in Nodal Staging of Resected Non-Small Cell Lung Cancer.

BACKGROUND: The aim of this study was to examine the validity of PET/CT scans in the preoperative identification of lymph node metastases (LNM) and compare them with postoperative outcomes. METHODS: In this retrospective study, we included 87 patients with a solitary lung nodule or biopsy-proven non-small cell lung cancer treated in our institution from 2009 to 2015. Patients were divided into two groups and four subgroups, depending on pre- and postoperative findings. RESULTS: According to our analysis, PET/CT scan has a sensitivity of 50%, a specificity of 88.89%, a positive predictive value of 63.16%, and a negative predictive value of 82.35%. Among the patients, 13.8% were downstaged in PET-CT, while 8% were upstaged. In 78.2% of cases, the PET/CT evaluation was consistent with the histology. Metastases without extracapsular invasion were seldom recognized on PET/CT. CONCLUSIONS: This analysis showed the significance of extracapsular tumor invasion, which causes an inflammatory reaction, on LNM, which is probably responsible for preoperative false-positive findings. In conclusion, PET/CT scans are very effective in identifying patients without tumors. Furthermore, it is highly probable that patients with negative findings are free of disease.

Inside the ß Cell: Molecular Stress Response Pathways in Diabetes Pathogenesis.

The pathogeneses of the 2 major forms of diabetes, type 1 and type 2, differ with respect to their major molecular insults (loss of immune tolerance and onset of tissue insulin resistance, respectively). However, evidence suggests that dysfunction and/or death of insulin-producing ß-cells is common to virtually all forms of diabetes. Although the mechanisms underlying ß-cell dysfunction remain incompletely characterized, recent years have witnessed major advances in our understanding of the molecular pathways that contribute to the demise of the ß-cell. Cellular and environmental factors contribute to ß-cell dysfunction/loss through the activation of molecular pathways that exacerbate endoplasmic reticulum stress, the integrated stress response, oxidative stress, and impaired autophagy. Whereas many of these stress responsive pathways are interconnected, their individual contributions to glucose homeostasis and ß-cell health have been elucidated through the development and interrogation of animal models. In these studies, genetic models and pharmacological compounds have enabled the identification of genes and proteins specifically involved in ß-cell dysfunction during diabetes pathogenesis. Here, we review the critical stress response pathways that are activated in ß cells in the context of the animal models.

Early insights of the COVID-19 pandemic in the Veterans' Affairs spinal cord injury and disorders population.

STUDY DESIGN: Retrospective cohort. OBJECTIVES: The primary outcome of the study was to identify patient characteristics associated with a positive COVID-19 test. The secondary outcome was to identify patient characteristics associated with mortality from COVID-19. SETTING: Veterans Health Administration (VHA) National Spinal Cord Injury and Disorders (SCI) Registry, created by the National Spinal Cord Injury and Disorders SCI Program Office in March 2020. METHODS: Data was analyzed in the form of descriptive statistics and then subsequent regression analysis was performed. RESULTS: A total of 4,562 persons with SCI were tested for COVID-19 between March and July 2020, and 290 were positive. The study found that African Americans had increased odds of testing positive for COVID-19 (OR 1.53 (1.18-2.00), p < 0.01). Increased age correlated with increased odds of mortality after testing positive for COVID-19 (1.046 (1.003-1.090)). Non-smokers had lower odds of mortality following positive COVID-19 test (0.15 (0.04-0.52)). No association was found between neurologic level of injury (NLI) and positive COVID-19 test or increased mortality. Increased Body Mass Index (BMI) did correlate with positive COVID-19 test but not increased mortality. The case fatality rate for persons with SCI and a positive test for COVID-19 was 12%. CONCLUSIONS: It is important to define the risk factors for patients with SCI to elucidate and mitigate individual and population risks. These risk factors also can play a role in determining the allocation of critical healthcare resources.

A short amphipathic alpha helix in scavenger receptor BI facilitates bidirectional HDL-cholesterol transport.

During reverse cholesterol transport, high-density lipoprotein (HDL) carries excess cholesterol from peripheral cells to the liver for excretion in bile. The first and last steps of this pathway involve the HDL receptor, scavenger receptor BI (SR-BI). While the mechanism of SR-BI-mediated cholesterol transport has not yet been established, it has long been suspected that cholesterol traverses through a hydrophobic tunnel in SR-BI's extracellular domain. Confirmation of a hydrophobic tunnel is hindered by the lack of a full-length SR-BI structure. Part of SR-BI's structure has been resolved, encompassing residues 405 to 475, which includes the C-terminal transmembrane domain and its adjacent extracellular region. Within the extracellular segment is an amphipathic helix (residues 427-436, referred to as AH(427-436)) that showed increased protection from solvent in NMR-based studies. Homology models predict that hydrophobic residues in AH(427-436) line a core cavity in SR-BI's extracellular region that may facilitate cholesterol transport. Therefore, we hypothesized that hydrophobic residues in AH(427-436) are required for HDL cholesterol transport. Here, we tested this hypothesis by mutating individual residues along AH(427-436) to a charged residue (aspartic acid), transiently transfecting COS-7 cells with plasmids encoding wild-type and mutant SR-BI, and performing functional analyses. We found that mutating hydrophobic, but not hydrophilic, residues in AH(427-436) impaired SR-BI bidirectional cholesterol transport. Mutating phenylalanine-430 was particularly detrimental to SR-BI's functions, suggesting that this residue may facilitate important interactions for cholesterol delivery within the hydrophobic tunnel. Our results support the hypothesis that a hydrophobic tunnel within SR-BI mediates cholesterol transport.

Prevalence and clinical significance of portal inflammation, portal plasma cells, interface hepatitis and biliary injury in liver biopsies from patients with non-alcoholic steatohepatitis.

The significance of portal tract histological changes in non-alcoholic fatty liver disease (NAFLD) remains unclear. In 2019, CymaBay Therapeutics halted clinical trials of seladelpar (a PPARδ agonist) because initial end-of-treatment liver biopsies of patients with non-alcoholic steatohepatitis (NASH) showed concerning features of portal inflammation with plasma cells, interface hepatitis and focal bile duct abnormalities. Adjudication concluded that these findings were present in the initial, as well as the subsequent biopsies. Thus, this study's aim was to determine the prevalence and clinical significance of portal inflammation, portal plasma cells, interface hepatitis and features of bile duct damage in liver biopsies of adult patients with NAFLD. The pathology database was searched for cases of NAFLD, including steatosis alone and NASH, from January 2016 to October 2020. Liver biopsies were selected from age and sex matched adult patients with diagnoses of steatosis alone (n=10), NASH fibrosis stage 1 (n=10), stage 2 (n=10), stage 3 (n=10), and stage 4 (n=10). There were 24 males and 26 females with a mean age of 48 years (range 20-79). Exclusion criteria included age <18 years, daily alcohol intake >14 drinks per week, elevation of alkaline phosphatase level, comorbid chronic liver disease, or liver biopsy performed as part of a clinical trial for NASH. Control liver biopsies were selected from age and sex matched persons without significant steatosis and normal liver biochemical tests (n=10). Histological parameters were evaluated in 10 portal tracts or 10 septal areas in each liver biopsy. Portal inflammation and interface hepatitis were graded on a scale of 0-4. Portal plasma cells and bile duct damage were scored from 0-3. Ductular proliferation was assessed by CK7 immunostain and graded from 0-4. NASH biopsies with advanced fibrosis (stage 3 and 4) showed portal inflammatory infiltrates (score 2-3) with readily identifiable plasma cells (score 2), and mild to moderate interface hepatitis (score 2-3). All cases and controls showed focal, mild cholangiocyte changes, characterised by cytoplasmic vacuolation, segmental loss of nuclei, nuclear disarray and apoptosis. NASH patients with advanced fibrosis had frequent and diffuse cholangiocyte changes, along with focal lymphocytic cholangitis and moderate to marked ductular reaction (score 3-4). Histopathological features of advanced NASH frequently include increased portal inflammation with plasma cells, interface hepatitis, cholangiocyte injury and prominent ductular reaction.