Plasma microRNA Interindividual Variability in Healthy Individuals, Pregnant Women, and an Individual with a Stably Altered Neuroendocrine Phenotype.

BACKGROUND: Extracellular RNAs (exRNAs) in biofluids are amenable to quantitative analysis and proposed as noninvasive biomarkers for monitoring organ function. Cell-lineage-specific microRNAs (miRNAs) are present in plasma as soluble ribonucleoproteins or enclosed in exRNA carriers and transported through the vasculature. However, more extensive studies of healthy individuals are needed to gain insights into the variability of plasma miRNA abundance and composition. METHODS: The exRNA composition of platelet-depleted plasma collected twice from 236 healthy individuals was characterized by small RNA sequencing. Plasma of pregnant women featuring dramatically increased placental miRNAs and samples from subject P12 with noticeably increased epithelial- and neuroendocrine-origin miRNAs were included for comparison. The miRNA content of 10 000g and 100 000g pellet fractions of plasma generated by ultracentrifugation was also determined. Data analysis methods included Pearson correlation, differential gene expression, and unsupervised clustering. RESULTS: The abundance changes for more variable miRNAs in plasma of normal individuals correlated between coexpressed cell-lineage-specific miRNAs of the liver, neuroendocrine organs, epithelial cells, and muscle. ExRNA of pellet fractions contained <2% of total plasma miRNA with modest enrichment of lineage-specific and variable miRNAs compared to supernatant. The abundance fold changes of miRNAs observed in pregnancy and P12 compared to normal exceeded interquartile variability of healthy individuals. The neuroendocrine miRNA signature of P12 persisted for more than 4 years and was absent in other individuals. CONCLUSIONS: This study defines the framework and effect size for screening of extensive plasma collections for miRNA phenotypes and biomarker discovery.

Riluzole, a glutamate modulator, slows cerebral glucose metabolism decline in patients with Alzheimer's disease.

Dysregulation of glutamatergic neural circuits has been implicated in a cycle of toxicity, believed among the neurobiological underpinning of Alzheimer's disease. Previously, we reported preclinical evidence that the glutamate modulator riluzole, which is FDA approved for the treatment of amyotrophic lateral sclerosis, has potential benefits on cognition, structural and molecular markers of ageing and Alzheimer's disease. The objective of this study was to evaluate in a pilot clinical trial, using neuroimaging biomarkers, the potential efficacy and safety of riluzole in patients with Alzheimer's disease as compared to placebo. A 6-month phase 2 double-blind, randomized, placebo-controlled study was conducted at two sites. Participants consisted of males and females, 50 to 95 years of age, with a clinical diagnosis of probable Alzheimer's disease, and Mini-Mental State Examination between 19 and 27. Ninety-four participants were screened, 50 participants who met inclusion criteria were randomly assigned to receive 50 mg riluzole (n = 26) or placebo (n = 24) twice a day. Twenty-two riluzole-treated and 20 placebo participants completed the study. Primary end points were baseline to 6 months changes in (i) cerebral glucose metabolism as measured with fluorodeoxyglucose-PET in prespecified regions of interest (hippocampus, posterior cingulate, precuneus, lateral temporal, inferior parietal, frontal); and (ii) changes in posterior cingulate levels of the neuronal viability marker N-acetylaspartate as measured with in vivo proton magnetic resonance spectroscopy. Secondary outcome measures were neuropsychological testing for correlation with neuroimaging biomarkers and in vivo measures of glutamate in posterior cingulate measured with magnetic resonance spectroscopy as a potential marker of target engagement. Measures of cerebral glucose metabolism, a well-established Alzheimer's disease biomarker and predictor of disease progression, declined significantly less in several prespecified regions of interest with the most robust effect in posterior cingulate, and effects in precuneus, lateral temporal, right hippocampus and frontal cortex in riluzole-treated participants in comparison to the placebo group. No group effect was found in measures of N-acetylaspartate levels. A positive correlation was observed between cognitive measures and regional cerebral glucose metabolism. A group × visit interaction was observed in glutamate levels in posterior cingulate, potentially suggesting engagement of glutamatergic system by riluzole. In vivo glutamate levels positively correlated with cognitive performance. These findings support our main primary hypothesis that cerebral glucose metabolism would be better preserved in the riluzole-treated group than in the placebo group and provide a rationale for more powered, longer duration studies of riluzole as a potential intervention for Alzheimer's disease.

A randomized clinical trial in vitamin D-deficient adults comparing replenishment with oral vitamin D3 with narrow-band UV type B light: effects on cholesterol and the transcriptional profiles of skin and blood.

Background: Vitamin D deficiency, defined as a serum 25-hydroxyvitamin D [25(OH)D] concentration <20 ng/mL, is correlated with a more atherogenic lipid profile. However, oral vitamin D supplementation does not lower LDL-cholesterol concentrations or raise HDL-cholesterol concentrations. This uncoupling between association and causation may result from a failure of oral vitamin D to mimic the effect of dermally synthesized vitamin D in response to ultraviolet type B (UVB) light.Objective: We tested the hypothesis that, in vitamin D-deficient adults, the replenishment of vitamin D with UVB exposure would lower LDL-cholesterol concentrations compared with the effect of oral vitamin D3 supplementation.Design: We performed a randomized clinical trial in vitamin D-deficient adults and compared vitamin D replenishment between subjects who received oral vitamin D3 (n = 60) and those who received narrow-band UVB exposure (n = 58) ≤6 mo.Results: There was no difference in the change from baseline LDL-cholesterol concentrations between oral vitamin D3 and UVB groups (difference in median of oral vitamin D3 minus that of UVB: 1.5 mg/dL; 95% CI: -5.0, 7.0 mg/dL). There were also no differences within groups or between groups for changes in total or HDL cholesterol or triglycerides. Transcriptional profiling of skin and blood, however, revealed significant upregulation of immune pathway signaling with oral vitamin D3 but significant downregulation with UVB.Conclusions: Correcting vitamin D deficiency with either oral vitamin D3 or UVB does not improve the lipid profile. Beyond cholesterol, these 2 modalities of raising 25(OH)D have disparate effects on gene transcription. This trial was registered at clinicaltrials.gov as NCT01688102.

The Rockefeller University Navigation Program: a structured multidisciplinary protocol development and educational program to advance translational research.

The development of translational clinical research protocols is complex. To assist investigators, we developed a structured supportive guidance process (Navigation) to expedite protocol development to the standards of good clinical practice (GCP), focusing on research ethics and integrity. Navigation consists of experienced research coordinators leading investigators through a concerted multistep protocol development process from concept initiation to submission of the final protocol. To assess the effectiveness of Navigation, we collect data on the experience of investigators, the intensity of support required for protocol development, IRB review outcomes, and protocol start and completion dates. One hundred forty-four protocols underwent Navigation and achieved IRB approval since the program began in 2007, including 37 led by trainee investigators, 26 led by MDs, 9 by MD/PhDs, 57 by PhDs, and 12 by investigators with other credentials (e.g., RN, MPH). In every year, more than 50% of Navigated protocols were approved by the IRB within 30 days. For trainees who had more than one protocol navigated, the intensity of Navigation support required decreased over time. Navigation can increase access to translational studies for basic scientists, facilitate GCP training for investigators, and accelerate development and approval of protocols of high ethical and scientific quality.

The short-term effects of vitamin D repletion on cholesterol: a randomized, placebo-controlled trial.

OBJECTIVE: Vitamin D deficiency is common and associated with dyslipidemia. However, it is unclear whether oral vitamin D supplementation improves the lipid profile. Therefore, we conducted a randomized, placebo-controlled trial to determine the short-term effects of vitamin D repletion on the lipid profile. METHODS AND RESULTS: One hundred fifty-one vitamin D-deficient (25-hydroxyvitamin D <20 ng/mL) adults with elevated risk for cardiovascular disease were randomized to receive either 50 000 IU of vitamin D3 weekly for 8 weeks or placebo. The primary outcome was the change in small low-density lipoprotein (LDL) particle number. Secondary outcomes included changes in other nuclear magnetic resonance-based and chemical lipid fractions. Vitamin D failed to improve the lipid profile. Compared with the placebo, vitamin D repletion did not change small LDL particle number (mean change, +18 nmol/L; 95% CI [-80 to +116 nmol/L]; P=0.63). There were also no changes in the chemical lipid profile: total cholesterol (+5.8 mg/dL, 95% CI [-1.4 to +13.0 mg/dL], P=0.14); LDL cholesterol (+3.8 mg/dL, 95% CI [-2.5 to +10.2 mg/dL], P=0.13); high-density lipoprotein cholesterol (+0.4 mg/dL 95% CI [-1.6 to +2.6 mg/dL], P=0.71); and triglycerides (+7.9 mg/dL 95% CI [-6.5 to +22.3 mg/dL]). In the vitamin D repletion group, exploratory multivariate regression analysis demonstrates that changes in LDL cholesterol were positively correlated with the changes in serum calcium (P<0.001) and inversely with the changes in serum parathyroid hormone (P=0.02). CONCLUSIONS: In contrast to the association between low 25-hydroxyvitamin D levels and dyslipidemia, correcting vitamin D deficiency in the short-term does not improve the lipid profile. Repletion of 25-hydroxyvitamin D levels raised serum calcium levels and decreased serum parathyroid hormone levels. These expected physiological responses to vitamin D therapy were correlated with a significant increase in LDL cholesterol. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT01008384.