Relation between myostatin levels and malnutrition and muscle wasting in hemodialysis patients.

BACKGROUND AND AIM: Malnutrition is one of the most troublesome comorbidities among hemodialysis patients (HD). Myostatin (MSTN) belongs to the transforming growth factor-ß superfamily. In HD patients, MSTN effects are not limited to skeletal muscle growth. The present study aimed to assess MSTN levels in HD patients and its relation to various clinical and biochemical parameters. PATIENTS AND METHODS: The present case control study included 60 patients on HD for at least three years. In addition, there were age and sex-matched healthy subjects who constitutes the control group. Nutritional status was evaluated using the malnutrition inflammation score (MIS). Muscle wasting in the present study was evaluated using the lean tissue index (LTI) as assessed by the body composition monitor (BCM). Rectus Femoris Muscle (RFM) thickness was also measured as indicator for nutritional status of patient. RESULTS: The present study included 60 HD patients, and ageand sex-matched healthy controls. Patients expressed significantly higher myostatin levels when compared to controls [median (IQR): 221.3 (153.5-688.2) versus 144.8 (97.0-281.7), p < 0.001]. According to MIS, patients were classified into those with no/mild malnutrition (n = 22) and others with moderate/severe malnutrition (n = 38). Comparison between the two subgroups revealed that the former group had significantly lower myostatin levels [167.7 (150.3-236.3) versus 341.7 (160.9-955.9), p = 0.004]. According to LTI, patients were classified into those with muscle wasting (n = 23) and others without muscle wasting (n = 37). Comparative analysis showed that patients in the former group had significantly higher myostatin levels [775.1 (325.1-2133.7) versus 161.8 (142.6-302.3), p < 0.001]. CONCLUSIONS: Myostatin seems to be a promising marker for identification of malnutrition and muscle wasting in HD patients.

Evaluation of circulating miR-16-5p and miR-223-5p in association with musculoskeletal ultrasonography seven-joint score in the assessment of rheumatoid arthritis activity.

Rheumatoid arthritis (RA) is characterized by ongoing joint destruction. MicroRNAs (miRs) are blood-based biomarkers linked to RA pathogenesis. The musculoskeletal ultrasonography seven-joint score (US7) is an objective tool to assess RA activity. We aimed to evaluate miR-223 and miR-16 roles in monitoring RA activity and to investigate if there is a link between their plasma levels and US7 score. This study enrolled 76 RA patients classified according to Disease Activity Score 28-joint count with erythrocyte sediment rate (DAS28-ESR) to inactive cases (n = 38) and active cases (n = 38). Each patient's joint was scored for synovial proliferation (gray-scale ultrasound 'GSUS7') and vascularization (power Doppler ultrasound 'PDUS7'). Real-time quantitative PCR was used to measure the expression levels of miR-16 and miR-223 in plasma. When compared to inactive group, the active group revealed significant upregulation of miR-16 and miR-223, (P = 0.001 and P = 0.02, respectively). miR-16 and miR-223 levels were correlated with synovitis PDUS7 (r = 0.34, p < 0.01 and r= 0.25, P = 0.03, respectively). miR-16 was also positively correlated with synovitis GSUS7 (r= 0.42, p < 0.001). miR-223 upregulation discriminated active from inactive RA patients at AUC = 0.64, with 76% sensitivity and 50% specificity at cutoff > 2.8-fold change), whereas miR-16 distinguished the two groups at AUC = 0.78 with 87% sensitivity and 53% specificity at cutoff >38.27-fold change. In conclusion, upregulated miR-16 may have more potential to serve as activity biomarkers than miR-223 in RA. The miR-16 level was linked to synovitis GSUS7 and synovitis PDUS7 changes but miR-223 only linked to synovitis PDUS.