Plasma from Patients with Rheumatoid Arthritis Reduces Nitric Oxide Synthesis and Induces Reactive Oxygen Species in A Cell-Based Biosensor

Exhaled Nitric Oxide Reflects the Immune Reactions of the Airways in Early Rheumatoid Arthritis

Patients with rheumatoid arthritis (RA) have altered levels of exhaled nitric oxide (NO) compared with healthy controls. Here, we investigated whether the clinical features of and immunological factors in RA pathogenesis could be linked to the NO lung dynamics in early disease. A total of 44 patients with early RA and anti-citrullinated peptide antibodies (ACPAs), specified as cyclic citrullinated peptide 2 (CCP2), were included. Their exhaled NO levels were measured, and the alveolar concentration, the airway compartment diffusing capacity and the airway wall concentration of NO were estimated using the Högman-Meriläinen algorithm. The disease activity was measured using the Disease Activity Score for 28 joints. Serum samples were analysed for anti-CCP2, rheumatoid factor, free secretory component, secretory component containing ACPAs, antibodies against Porphyromonas gingivalis (Rgp) and total levels of IgA, IgA1 and IgA2. Significant negative correlations were found between the airway wall concentration of NO and the number of swollen joints (Rho -0.48, p = 0.004), between the airway wall concentration of NO and IgA rheumatoid factor (Rho -0.41, p = 0.017), between the alveolar concentration and free secretory component (Rho -0.35, p = 0.023) and between the alveolar concentration and C-reactive protein (Rho -0.36, p = 0.016), but none were found for anti-CCP2, IgM rheumatoid factor or the anti-Rgp levels. In conclusion, altered NO levels, particularly its production in the airway walls, may have a role in the pathogenesis of ACPA-positive RA.

NAD+-boosting compounds enhance nitric oxide production and prevent oxidative stress in endothelial cells exposed to plasma from patients with COVID-19

SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), induces vascular endothelial dysfunction, but the mechanisms are unknown. We tested the hypothesis that the "circulating milieu" (plasma) of patients with COVID-19 would cause endothelial cell dysfunction (characterized by lower nitric oxide (NO) production), which would be linked to greater reactive oxygen species (ROS) bioactivity and depletion of the critical metabolic co-substrate, nicotinamide adenine dinucleotide (NAD+). We also investigated if treatment with NAD+-boosting compounds would prevent COVID-19-induced reductions in endothelial cell NO bioavailability and oxidative stress. Human aortic endothelial cells (HAECs) were exposed to plasma from men and women (age 18-85 years) who were hospitalized and tested positive (n = 34; 20 M) or negative (n = 13; 10 M) for COVID-19. HAECs exposed to plasma from patients with COVID-19 also were co-incubated with NAD+ precursors nicotinamide riboside (NR) or nicotinamide mononucleotide (NMN). Acetylcholine-stimulated NO production was 27% lower and ROS bioactivity was 54% higher in HAECs exposed to plasma from patients with COVID-19 (both p < 0.001 vs. control); these responses were independent of age and sex. NAD+ concentrations were 30% lower in HAECs exposed to plasma from patients with COVID-19 (p = 0.001 vs. control). Co-incubation with NR abolished COVID-19-induced reductions in NO production and oxidative stress (both p > 0.05 vs. control). Co-treatment with NMN produced similar results. Our findings suggest the circulating milieu of patients with COVID-19 promotes endothelial cell dysfunction, characterized by lower NO bioavailability, greater ROS bioactivity, and NAD+ depletion. Supplementation with NAD+ precursors may exert a protective effect against COVID-19-evoked endothelial cell dysfunction and oxidative stress.

Treatment of Cardiovascular Disease in Rheumatoid Arthritis: A Complex Challenge with Increased Atherosclerotic Risk

Rheumatoid arthritis (RA) carries significant risk for atherosclerotic cardiovascular disease (ASCVD). Traditional ASCVD risk factors fail to account for this accelerated atherosclerosis. Shared inflammatory pathways are fundamental in the pathogenesis of both diseases. Considering the impact of RA in increasing cardiovascular morbidity and mortality, the characterization of therapies encompassing both RA and ASCVD management merit high priority. Despite little progress, several drugs discussed here promote remission and or lower rheumatoid disease activity while simultaneously conferring some level of atheroprotection. Methotrexate, a widely used disease-modifying drug used in RA, is associated with significant reduction in cardiovascular adverse events. MTX promotes cholesterol efflux from macrophages, upregulates free radical scavenging and improves endothelial function. Likewise, the sulfonamide drug sulfasalazine positively impacts the lipid profile by increasing HDL-C, and its use in RA has been correlated with reduced risk of myocardial infraction. In the biologic class, inhibitors of TNF-α and IL-6 contribute to improvements in endothelial function and promote anti-atherogenic properties of HDL-C, respectively. The immunosuppressant hydroxychloroquine positively affects insulin sensitization and the lipid profile. While no individual therapy has elicited optimal atheroprotection, further investigation of combination therapies are ongoing.