Molecular Transducers of Physical Activity Consortium (MoTrPAC) - Pediatric Protocol

The goal of the Molecular Transducers of Physical Activity Consortium (MoTrPAC) is to assess molecular changes that occur in response to physical activity (PA). To achieve this aim, studies will be conducted in adults and separately in children and adolescents. The UC Irvine MoTrPAC Pediatric Clinical Center oversees two interrelated study phases in children and adolescents:

1. A cross-sectional phase in which molecular transducers (obtained from blood sampling) are measured in response to an acute exercise challenge (n = 320);
2. An intervention phase is conducted as a mechanistic randomized controlled trial (RCT). Participants are recruited from the cross-sectional study phase and randomized to endurance exercise (EE) training (n = 120) or no exercise Control (n = 50) for a period of approximately 12 weeks.

The overarching hypothesis is that there are discoverable molecular transducers that communicate and coordinate the effects of exercise on cells, tissues, and organs, which may initiate processes ultimately leading to the health benefits of exercise. Because this is a mechanistic trial, the main goal is not a single health-related outcome. Rather, the goal is to generate a resource leading to the generation of a map of the molecular responses to exercise that will be used by the Consortium and by the scientific community at large to generate hypotheses for future investigations of the health benefits of PA. Study assessments are completed before and after the intervention period (exercise or control), and at specific interim time points during the intervention. An additional focus of the pediatric studies is to examine the impact of sex and developmental phase (self-reported pubertal stage) during childhood and adolescence on acute and chronic exercise responses.

Assessments include measurements of cardiorespiratory fitness, muscular strength, and body composition (including whole body bone mineral content) determined by dual-energy x-ray absorptiometry (DXA). There is also collection of blood, monitoring of free-living PA level using wearable devices, and completion of participant reported outcomes and health status by interview and/or questionnaire. As part of the MoTrPAC functions, participant data and biological samples are transferred from the Pediatric Clinical Site to the Consortium Coordinating Center (CCC) Data Management, Analysis and Quality Control Center (DMAQC) and to the Biological Sample Repository, and later analyzed by the Consortium Chemical Analysis Sites (CAS) and the Bioinformatics Center (BIC).

Biological samples collected in this project undergo molecular phenotyping, including metabolomic, lipidomic, proteomic, epigenomic, transcriptomic, and genomic analyses. These assays are done at the MoTrPAC CAS.

Overall coordination of the study and analyses occurs at 4 institutions which make up the CCC and the BIC.