High Dose Omega-3 Fatty Acid Administration and Skeletal Muscle Protein Turnover in Maintenance Hemodialysis Patients.

BACKGROUND AND OBJECTIVES: Protein energy wasting and systemic inflammation are prevalent in maintenance hemodialysis (MHD) patients. Omega-3 (ω-3) fatty acids have anti-inflammatory properties and have been shown to improve protein homeostasis. We hypothesized that administration of high-dose (2.9 g/d) ω-3 would be associated with decreased muscle protein breakdown in MHD patients with systemic inflammation. DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS: This is a substudy from a randomized, placebo-controlled study (NCT00655525). Patients were recruited between September 2008 and June 2011. Primary inclusion criteria included signs of chronic inflammation (average C-reactive protein of ≥5 mg/L over three consecutive measurements), lack of active infectious or inflammatory disease, no hospitalization within 1 month prior to the study, and not receiving steroids (>5 mg/d) and/or immunosuppressive agents. The primary outcomes were forearm muscle and whole body protein breakdown and synthesis before and after the intervention. The patients received ω-3 (n=11) versus placebo (n=9) for 12 weeks. Analysis of covariance was used to compare outcome variables at 12 weeks. Models were adjusted for a propensity score that was derived from age, sex, race, baseline high sensitivity C-reactive protein, diabetes mellitus, and fat mass because the groups were not balanced for several characteristics. RESULTS: Compared with placebo, ω-3 supplementation was significantly associated with decreased muscle protein breakdown at 12 weeks (-31, [interquartile range, -98--13] versus 26 [interquartile range, 13-87] µg/100 ml per min; P=0.01), which remained significant after multivariate adjustment (-46, [95% confidence interval, -102 to -1] µg/100 ml per min). ω-3 Supplementation resulted in decreased forearm muscle protein synthesis while the rate in the placebo group increased; however, there is no longer a statistically significant difference in skeletal muscle protein synthesis or in net protein balance after multivariate adjustment. There was no statistically significant effect of ω-3 supplementation on whole body protein synthesis or breakdown. CONCLUSIONS: High-dose ω-3 supplementation over 12 weeks in MHD patients with systemic inflammation was associated with attenuation of forearm muscle protein breakdown but did not influence skeletal muscle protein synthesis, skeletal muscle net protein balance or any component of the whole-body protein balance. These results should be interpreted cautiously given the imbalance in the two groups and the short duration of the intervention.

Association between hemoglobin, calcium, and lactate dehydrogenase variability and mortality among metastatic renal cell carcinoma.

PURPOSE: There are no robust data on hemoglobin (Hb), lactate dehydrogenase (LDH), and calcium variability for overall survival (OS) in patients with metastatic renal cell carcinoma (mRCC) treated with vascular endothelial growth factor (VEGF)-targeted therapy. We aim to evaluate prognostic implications of Hb, LDH, and calcium variability and establish a novel risk stratification model in RCC patients receiving targeted therapies. METHODS: We retrospectively studied an unselected cohort of patients with mRCC, who were treated with tyrosine kinase inhibitors. We assessed LDH variability, Ca variability, and Hb variability with various methods using standard deviation and fluctuation across thresholds. Kaplan-Meier and log-rank analyses were employed on OS and multivariate Cox proportional hazard model analyzed clinical parameters for their prognostic relevance. RESULTS: A total of 59 patients intermediate-risk group according to the Memorial Sloan-Kettering Cancer Center with mRCC who had early progressed after first-line therapy with interferon-α were included in this retrospective single-center study conducted between February 2008 and December 2011. The mean Hb was 12.4 g/dl (min-max 9.1-15.2) throughout the study. Multivariable-adjusted Cox regression showed that patients in the consistently low-Hb group and patients in the low-amplitude and high-amplitude groups had a statistically significant increase in risk compared with patients who were consistently on target (HR 4.1; 95 % CI 1.3-12.9 and HR 2.9; 95 % CI 1.05-8.1 and HR 4.4; 95 % CI 1.7-11.1, respectively). On the other hand, the higher mean LDH (LDH more than 1 >upper limit of normal) was associated with OS. LDH variability and Ca variability were not associated with mortality. CONCLUSIONS: In patients with mRCC treated with VEGF-targeted therapy, Hb variability and mean LDH level might be associated with OS. This should be investigated prospectively.