POS0678 DOES SILDENAFIL IMPROVE ENDOTHELIAL DYSFUNCTION IN RHEUMATOID ARTHRITIS? – A PILOT CLINICAL TRIAL

Background:

Rheumatoid arthritis (RA) is independently associated with an increased risk of cardiovascular disease (CVD). One of the early stages of atherosclerosis is endothelial dysfunction, which is increased in RA. Using drugs to target endothelial dysfunction is a promising novel strategy for CVD prevention in RA. Sildenafil has been shown to improve endothelial function in diabetics, who have similar increased CVD risk. Our hypothesis was that sildenafil use may be a novel primary CVD prevention strategy in RA.

Objectives:

To determine if sildenafil use in RA patients improves endothelial dysfunction (as measured by brachial artery flow-mediated dilation [FMD] and peripheral arterial tone [PAT]), as well as serum inflammatory and atherosclerosis biomarkers.

Methods:

This NIH-funded study was a phase II, randomized double-blind placebo-controlled crossover efficacy trial of 25 RA patients, with no known history of CVD, but at least one traditional CVD risk factor. Patients were randomized 1:1 to receive either sildenafil or placebo for 3 months, then after a 2-week washout, crossed over to each respective group for an additional 3 months. Vascular studies (FMD and PAT) and serum atherosclerosis biomarkers (e-Selectin, ICAM-1, VCAM-1) were performed at baseline, 3 months pre- and post-washout, and 6 months. Adverse events were collected. Given the cross-over design, analyses included a random effects model for within-subject comparisons of sildenafil versus placebo periods, adjusting for the baseline (FMD or EndoPAT) within that period and a term for treatment order. All tests were 2-sided with α=0.05.

Results:

A total of 233 subjects were assessed for eligibility, with 25 subjects being randomized after written informed consent. A total of 13 subjects were randomized to placebo first, and 12 to sildenafil first. Baseline characteristics were similar between those randomized to Placebo vs. Sildenafil first. Mean age was 62.0+/-10.9 years; 84% were female; and 92% were white. A total of 6 adverse events experienced in 3 subjects occurred. The primary endpoint (increase in %FMD in Sildenafil period vs. Placebo period) was not significant (p=0.19). However, note the study was powered at 80% to detect an effect size of 0.37 for change in %FMD or biomarker with a sample size of 60, not 25. However, sildenafil use was associated with a significant increase (improvement) by 0.200 units of PAT ratio (p=0.003) compared with placebo, adjusted by treatment order and baseline PAT ratio (within the given treatment period). Exploratory linear mixed models comparing e-Selectin, ICAM-1, and VCAM-1 between Sildenafil vs. Placebo periods, adjusted for treatment order and the baseline biomarker level, did not show any significant differences except for ICAM-1 (55.3 units higher in Sildenafil vs. Placebo periods, p=0.011).

Conclusion:

In this pilot trial of 25 RA subjects, sildenafil use was associated with a significant increase (improvement) in endothelial function as measured by PAT. However, there was no significant difference in FMD. The study is limited due to the small sample size, which was impacted by slow recruitment as well as the COVID-19 pandemic. Future larger studies are required to assess whether other PDE5 inhibitors may improve endothelial dysfunction in RA and other autoimmune disease patients at high risk of CVD.

References:

[1]Maradit-Kremers H, Crowson CS, Nicola PJ, et al. Increased unrecognized coronary heart disease and sudden deaths in rheumatoid arthritis: a population-based cohort study. Arthritis Rheum 2005;52:402-11.

[2]Peters MJ, van Halm VP, Voskuyl AE, et al. Does rheumatoid arthritis equal diabetes mellitus as an independent risk factor for cardiovascular disease? A prospective study. Arthritis Rheum 2009;61:1571-9.

[3]Deyoung L, Chung E, Kovac JR, et al. Daily use of sildenafil improves endothelial function in men with type 2 diabetes. J Andrology 2012;33:176-80.

Disclosure of Interests:

None declared

Banff Histopathological Consensus Criteria for Preimplantation Kidney Biopsies

The Banff working group on preimplantation biopsy was established to develop consensus criteria (best practice guidelines) for the interpretation of preimplantation kidney biopsies. Digitally scanned slides were used (i) to evaluate interobserver variability of histopathologic findings, comparing frozen sections with formalin-fixed, paraffin-embedded tissue of wedge and needle core biopsies, and (ii) to correlate consensus histopathologic findings with graft outcome in a cohort of biopsies from international medical centers. Intraclass correlations (ICCs) and univariable and multivariable statistical analyses were performed. Good to fair reproducibility was observed in semiquantitative scores for percentage of glomerulosclerosis, arterial intimal fibrosis and interstitial fibrosis on frozen wedge biopsies. Evaluation of frozen wedge and core biopsies was comparable for number of glomeruli, but needle biopsies showed worse ICCs for glomerulosclerosis, interstitial fibrosis and tubular atrophy. A consensus evaluation form is provided to help standardize the reporting of histopathologic lesions in donor biopsies. It should be recognized that histologic parameters may not correlate with graft outcome in studies based on organs deemed to be acceptable after careful clinical assessment. Significant limitations remain in the assessment of implantation biopsies.

Elevated ST2 Distinguishes Incidences of Pediatric Heart and Small Bowel Transplant Rejection

Elevated serum soluble (s) suppressor of tumorigenicity-2 is observed during cardiovascular and inflammatory bowel diseases. To ascertain whether modulated ST2 levels signify heart (HTx) or small bowel transplant (SBTx) rejection, we quantified sST2 in serially obtained pediatric HTx (n = 41) and SBTx recipient (n = 18) sera. At times of biopsy-diagnosed HTx rejection (cellular and/or antibody-mediated), serum sST2 was elevated compared to rejection-free time points (1714 ± 329 vs. 546.5 ± 141.6 pg/mL; p = 0.0002). SBTx recipients also displayed increased serum sST2 during incidences of rejection (7536 ± 1561 vs. 2662 ± 543.8 pg/mL; p = 0.0347). Receiver operator characteristic (ROC) analysis showed that serum sST2 > 600 pg/mL could discriminate time points of HTx rejection and nonrejection (area under the curve [AUC] = 0.724 ± 0.053; p = 0.0003). ROC analysis of SBTx measures revealed a similar discriminative capacity (AUC = 0.6921 ± 0.0820; p = 0.0349). Quantitative evaluation of both HTx and SBTx biopsies revealed that rejection significantly increased allograft ST2 expression. Pathway and Network Analysis of biopsy data pinpointed ST2 in the dominant pathway modulated by rejection and predicted tumor necrosis factor-α and IL-1β as upstream activators. In total, our data indicate that alloimmune-associated pro-inflammatory cytokines increase ST2 during rejection. They also demonstrate that routine serum sST2 quantification, potentially combined with other biomarkers, should be investigated further to aid in the noninvasive diagnosis of rejection.

Regional brain injury on conventional and diffusion weighted MRI is associated with outcome after pediatric cardiac arrest

BACKGROUND

To assess regional brain injury on magnetic resonance imaging (MRI) after pediatric cardiac arrest (CA) and to associate regional injury with patient outcome and effects of hypothermia therapy for neuroprotection.

METHODS

We performed a retrospective chart review with prospective imaging analysis. Children between 1 week and 17 years of age who had a brain MRI in the first 2 weeks after CA without other acute brain injury between 2002 and 2008 were included. Brain MRI (1.5 T General Electric, Milwaukee, WI, USA) images were analyzed by 2 blinded neuroradiologists with adjudication; images were visually graded. Brain lobes, basal ganglia, thalamus, brain stem, and cerebellum were analyzed using T1, T2, and diffusion-weighted images (DWI).

RESULTS

We examined 28 subjects with median age 1.9 years (IQR 0.4-13.0) and 19 (68 %) males. Increased intensity on T2 in the basal ganglia and restricted diffusion in the brain lobes were associated with unfavorable outcome (all P < 0.05). Therapeutic hypothermia had no effect on regional brain injury. Repeat brain MRI was infrequently performed but demonstrated evolution of lesions.

CONCLUSION

Children with lesions in the basal ganglia on conventional MRI and brain lobes on DWI within the first 2 weeks after CA represent a group with increased risk of poor outcome. These findings may be important for developing neuroprotective strategies based on regional brain injury and for evaluating response to therapy in interventional clinical trials.

Determining sample size and a passing criterion for respirator fit-test panels

Few studies have proposed methods for sample size determination and specification of passing criterion (e.g., number needed to pass from a given size panel) for respirator fit-tests. One approach is to account for between- and within- subject variability, and thus take full advantage of the multiple donning measurements within subject, using a random effects model. The corresponding sample size calculation, however, may be difficult to implement in practice, as it depends on the model-specific and test panel-specific variance estimates, and thus does not yield a single sample size or specific cutoff for number needed to pass. A simple binomial approach is therefore proposed to simultaneously determine both the required sample size and the optimal cutoff for the number of subjects needed to achieve a passing result. The method essentially conducts a global search of the type I and type II errors under different null and alternative hypotheses, across the range of possible sample sizes, to find the lowest sample size which yields at least one cutoff satisfying, or approximately satisfying all pre-determined limits for the different error rates. Benchmark testing of 98 respirators (conducted by the National Institute for Occupational Safety and Health) is used to illustrate the binomial approach and show how sample size estimates from the random effects model can vary substantially depending on estimated variance components. For the binomial approach, probability calculations show that a sample size of 35 to 40 yields acceptable error rates under different null and alternative hypotheses. For the random effects model, the required sample sizes are generally smaller, but can vary substantially based on the estimate variance components. Overall, despite some limitations, the binomial approach represents a highly practical approach with reasonable statistical properties.

Effects of lipodystrophy on quality of life and depression in HIV-infected men on HAART

The aim of the study was a prospective assessment of the possible consequences of a diagnosis of lipodystrophy on health-related quality of life (HRQL) and depressive symptomatology in HIV-seropositive men who have sex with men. A standardized physical assessment for lipodystrophy was introduced within a prospective study in April 1999. Over a 2-year follow- up, 37 HIV-seropositive men who met the criteria for lipodystrophy were longitudinally compared to 92 HIV-seropositive men without lipodystrophy and 88 HIV-seronegative men on measures of HRQL and depression. A series of questionnaires, which included the Medical Outcomes Study Short-Form 36 (SF-36) and the Center for Epidemiological Studies-Depression (CES-D), were administered to assess HRQL and depression, respectively. SF-36 scores were summarized using the mental and physical components; CES-D results were reported as both dichotomous (with or with clinical depression) and continuous scores. Neither the mental nor physical components of the SF-36 showed any significant differences between patients with lipodystrophy versus HIV-seropositive patients without lipodystrophy. Similarly, lipodystrophy status was not significantly associated with either continuous depression scores or presence of clinical depression. However, consistent with previous results, HIV-seropositive men without lipodystrophy (compared to HIV-seronegative men) reported higher scores on both components of the SF-36 scales and both categorizations of the CES-D. The results of this study suggest that lipodystrophy does not negatively affect HRQL or depression, above and beyond, the diagnosis of HIV infection, although the impact of the severity of lipodystrophy on these conditions will require further study.

Time course of pulmonary response of rats to inhalation of crystalline silica: histological results and biochemical indices of damage, lipidosis, and fibrosis

Previous studies have determined that alpha-quartz (crystalline silica) can cause pulmonary inflammation, damage, and fibrosis. However, the temporal relationship between silica inhalation and pulmonary inflammation, damage, and fibrosis has not been fully examined. To address this gap in our knowledge of silica-induced pulmonary fibrosis, a chronic inhalation study using rats was designed. Specifically, rats were exposed to a silica aerosol (15 mg/m3 silica, 6 h/d, 5 d/wk, 116 d), and measurements of pulmonary inflammation, damage, and fibrosis were monitored throughout the study. We report (1) data demonstrating that the silica aerosol generation and exposure system produced a consistent silica aerosol of respirable size particles; (2) the time course of silica deposition in the lung; (3) calculations that demonstrate that the rats were not in pulmonary overload; (4) histopathological data demonstrating time-dependent enhancement of silica-induced alveolitis, epithelial hypertrophy and hyperplasia, alveolar lipoproteinosis, and pulmonary fibrosis in the absence of overload; and (5) biochemical data documenting the development of lipidosis, lung damage, and fibrosis.

An in vitro comparison of the susceptibilities of bacterial isolates from patients with conjunctivitis and blepharitis to newer and established topical antibiotics

This retrospective study compared new and established topical antibiotics with regard to the in vitro susceptibility of bacterial isolates recovered from patients with conjunctivitis (n = 385) and blepharitis (n = 173) using the National Committee for Clinical Laboratory Standards-approved disk diffusion method. The percent susceptibility of recovered isolates to single antibiotic agents or combinations were ranked from greatest to least: chloramphenicol, bacitracin/polymyxin B, ofloxacin, sulfa, ciprofloxacin, trimethoprim/polymyxin B, norfloxacin, gentamicin, bacitracin, trimethoprim, tobramycin, neomycin, erythromycin, and polymyxin B. We determined that none of the available topical antibiotics provided 100% broad spectrum coverage in vitro. Established antibiotics often provided coverage comparable to the newer drugs. Due to the unproven value of in vitro testing as a predictor of clinical outcome in bacterial blepharitis and conjunctivitis, the ophthalmologist should choose therapy based on clinical experience, ongoing critical evaluation of available antibiotics, and cost-effectiveness.