Repeatability of exercise-induced changes in mRNA expression and technical considerations for qPCR analysis in human skeletal muscle.

NEW FINDINGS: What is the central question of this study? Are individual changes in exercise-induced mRNA expression repeatable (i.e. representative of the true response to exercise rather than random error)? What is the main finding and its importance? Exercise-induced changes in mRNA expression are not repeatable even under identical experimental conditions, thereby challenging the use of mRNA expression as a biomarker of adaptive potential and/or individual responsiveness to exercise. ABSTRACT: It remains unknown if (1) the observed change in mRNA expression reflects an individual's true response to exercise or random (technical and/or biological) error, and (2) the individual responsiveness to exercise is protocol-specific. We examined the repeatability of skeletal muscle PGC-1α, PDK4, NRF-1, VEGF-A, HSP72 and p53 mRNA expression following two identical endurance exercise (END) bouts (END-1, END-2; 30 min of cycling at 65% of peak work rate (WRpeak ), n = 11) and inter-individual variability in PGC-1α and PDK4 mRNA expression following END and sprint interval training (SIT; 8 × 20 s cycling intervals at ∼170% WRpeak , n = 10) in active young males. The repeatability of key gene analysis steps (RNA extraction, reverse transcription, qPCR) and within-sample fibre-type distribution (n = 8) was also determined to examine potential sources of technical error in our analyses. Despite highly repeatable exercise bout characteristics (work rate, heart rate, blood lactate; ICC > 0.71; CV < 10%; r > 0.85, P < 0.01), gene analysis steps (ICC > 0.73; CV < 24%; r > 0.75, P < 0.01), and similar group-level changes in mRNA expression, individual changes in PGC-1α, PDK4, VEGF-A and p53 mRNA expression were not repeatable (ICC < 0.22; CV > 20%; r < 0.21). Fibre-type distribution in two portions of the same muscle biopsy was highly variable and not significantly related (ICC = 0.39; CV = 26%; r = 0.37, P = 0.37). Since individual changes in mRNA expression following identical exercise bouts were not repeatable, inferences regarding individual responsiveness to END or SIT were not made. Substantial random error exists in changes in mRNA expression following acute exercise, thereby challenging the use of mRNA expression for analysing individual responsiveness to exercise.

Pregnancy Outcomes Following In Utero Exposure to Lamotrigine: A Systematic Review and Meta-Analysis.

INTRODUCTION: Lamotrigine is used in pregnancy to control epilepsy and mood disorders. The reproductive safety of this widely used drug remains undefined and may represent a significant public health concern. OBJECTIVE: We aimed to perform a systematic review and meta-analysis of existing knowledge related to malformation rates and maternal-neonatal outcomes after in utero exposure to monotherapy with lamotrigine. METHODS: Relevant studies were identified through systematic searches conducted in MEDLINE (Ovid), Embase (Ovid), CENTRAL (Ovid), and Web of Science (Thomson Reuters) from database inception to July 2016; no language or date restrictions were applied. All publications of clinically relevant outcomes of pregnancies following in utero exposure to lamotrigine were included in this systematic review and meta-analysis. RESULTS: A total of 21 studies describing immediate pregnancy outcomes and rates of congenital malformations fulfilled the inclusion criteria. Compared with disease-matched controls (n = 1412, total number of patients) and healthy controls (n = 774,571, total number of patients), in utero exposure to lamotrigine monotherapy was found to be associated with significantly decreased rates of inborn defects (odds ratio [OR] 1.15; 95% confidence interval [CI] 0.62-2.16 and OR 1.25; 95% CI 0.89-1.74, respectively). Rates of miscarriages, stillbirths, preterm deliveries, and small for gestational age (SGA) neonates were not found to have been increased after in-utero exposure to LTG compared to the general population. Similarly, in utero exposure to lamotrigine monotherapy was not found to be associated with increased rates of inborn defects compared with in utero exposure to carbamazepine, and lamotrigine was found to be statistically significantly less teratogenic than valproic acid (n = 12,958 and 10,748; OR 0.84; 95% CI 0.68-1.03 and OR 0.32; 95% CI 0.26-0.39, respectively). CONCLUSION: No association was found between prenatal lamotrigine monotherapy and increased rates of birth defects and other explored variables related to adverse pregnancy outcomes.