Serum vitamin D status inversely associates with a prevalence of severe sarcopenia among female patients with rheumatoid arthritis.

Sarcopenia is an age-related disease with an increased risk of mortality. It is emerging that low serum 25-hydroxyvitamin D [25(OH)D] affects the sarcopenic state in general, but in rheumatoid arthritis (RA), these associations are not understood although the prevalence of vitamin D insufficiency is high in RA. We conducted a cross-sectional study of older female outpatients from our cohort (KURAMA) database. We measured skeletal muscle mass, handgrip strength, and gait-speed to diagnose severe sarcopenia. The serum 25(OH)D concentration was measured using electrochemiluminescence immunoassay. A total of 156 female patients with RA (sarcopenia:44.9%, severe sarcopenia: 29.5%, and without sarcopenia: 25.6%) were enrolled. Classification of vitamin D status at a cutoff point of median 25(OH)D concentration revealed that low 25(OH)D status was associated with a high prevalence of severe sarcopenia and with low measured values of muscle mass, handgrip, and gait speed. Furthermore, multivariable logistic regression analysis identified that low 25(OH)D status was associated with a high prevalence of severe sarcopenia (OR 6.00; 95% CI 1.99-18.08).The same association was observed when the cut-off value was set at 20 ng/ml. In components of sarcopenia, both low physical performance and muscle mass were associated with low 25(OH)D status. In conclusion, vitamin D status was inversely associated with severe sarcopenia, low physical performance, and low skeletal muscle mass. Modification of vitamin D status including vitamin D supplementation should be investigated as a therapeutic strategy for sarcopenic patients with RA.

Urinary sodium-to-potassium ratio associates with hypertension and current disease activity in patients with rheumatoid arthritis: a cross-sectional study.

BACKGROUND: Excessive salt intake is thought to exacerbate both development of hypertension and autoimmune diseases in animal models, but the clinical impact of excessive salt in rheumatoid arthritis (RA) patients is still unknown. We performed a cross-sectional study to clarify the associations between salt load index (urinary sodium-to-potassium ratio (Na/K ratio)), current disease activity, and hypertension in an RA population. METHODS: Three hundred thirty-six participants from our cohort database (KURAMA) were enrolled. We used the spot urine Na/K ratio as a simplified index of salt loading and used the 28-Joint RA Disease Activity Score (DAS28-ESR) as an indicator of current RA disease activity. Using these indicators, we evaluated statistical associations between urinary Na/K ratio, DAS28-ESR, and prevalence of hypertension. RESULTS: Urinary Na/K ratio was positively associated with measured systolic and diastolic blood pressure and also with prevalence of hypertension even after covariate adjustment (OR 1.34, p <  0.001). In addition, increased urinary Na/K ratio was significantly and positively correlated with DAS28-ESR in multiple regression analysis (estimate 0.12, p <  0.001), as was also the case in gender-separated and prednisolone-separated sub-analyses. CONCLUSION: Urinary Na/K ratio was independently associated with current disease activity as well as with prevalence of hypertension in RA patients. Thus, dietary modifications such as salt restriction and potassium supplementation should be investigated as a potential candidate for attenuating both disease activity and hypertension in RA patients.

CSAHi study: Detection of drug-induced ion channel/receptor responses, QT prolongation, and arrhythmia using multi-electrode arrays in combination with human induced pluripotent stem cell-derived cardiomyocytes.

INTRODUCTION: The use of multi-electrode arrays (MEA) in combination with human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provides a promising method to predict comprehensive cardiotoxicity, including drug-induced QT prolongation and arrhythmia. We previously demonstrated that MEA in combination with hiPSC-CMs could provide a generalizable platform by using 7 reference drugs at 10 testing facilities. Using this approach, we evaluated responses to reference drugs that modulate a range of cardiac ion currents and have a range of arrhythmogenic effects. METHODS: We used the MEA system (MED64) and commercially available hiPSC-CMs (iCell cardiomyocytes) to evaluate drug effects on the beat rate, field potential duration (FPD), FPD corrected by Fridericia's formula (FPDc), and the incidence of arrhythmia-like waveforms. RESULTS: This assay detected the repolarization effects of Bay K8644, mibefradil, NS1643, levcromakalim, and ouabain; and the chronotropic effects of isoproterenol, ZD7288, and BaCl2. Chronotropy was also affected by K+ and Ca2+ current modulation. This system detected repolarization delays and the arrhythmogenic effects of quinidine, cisapride, thioridazine, astemizole, bepridil, and pimozide more sensitively than the established guinea pig papillary muscle action potential assay. It also predicted clinical QT prolongation by drugs with multiple ion channel effects (fluoxetine, amiodarone, tolterodine, vanoxerine, alfuzosin, and ranolazine). DISCUSSION: MEA in combination with hiPSC-CMs may provide a powerful method to detect various cardiac electrophysiological effects, QT prolongation, and arrhythmia during drug discovery. However, the data require careful interpretation to predict chronotropic effects and arrhythmogenic effects of candidate drugs with multiple ion channel effects.

[Mass surveys for detection of colorectal cancer].

In Japan, an immunochemical fecal occult test is the first step in mass surveys for detection of a colorectal cancer. A person with false-negative fecal occult blood has early cancer and/or cancer less than 3 cm in diameter. If the end of the mass survey is mp cancer (cancer involvement to the colonic wall), the false-negative rate for colorectal cancer is less than 10%. A person with a positive reaction on the fecal occult test is taken forward to the second step. The second step in the mass survey consists of barium enema or/and endoscopy. Endoscopic false-negative cancers are located behind the physical flexure section or the colonic haustra. Radiologic false-negative cancers are type II cancer or cancer less than 1 cm in diameter or on the right side of the colon. In our experience, we have rarely overlooked cancer more than 2.1 cm in diameter by colonoscopy or barium enema. Most mp cancers are more than 2 cm in diameter. Thus, with colonoscopy or radiology we overlooks less than 10% of mp cancer.