Icon Legend

This session is not in your schedule.

This session is in your schedule. Click again to remove it.

Session: Energy and Macronutrient Metabolism (Poster Theater Flash Session 1)

(PTFS01-03-24) Circulating microRNA Responses During Marine Amphibious Training

Saturday, June 29, 2024

3:08 PM – 3:12 PM CT

Location: W185A-C

Presenting Author(s)

CC

Christopher T. Carrigan, BS

Research Physiologist
U.S. Army Research Institute of Environmental Medicine
Natick, Massachusetts, United States

Disclosure(s): No relevant financial relationship(s) with ineligible companies to disclose.

Co-Author(s)

MW

Marques A. Wilson

USARIEM
MO

Michelle N. Ott

U.S. Army Research Institute of Environmental Medicine, United States
NM

Nancy E. Murphy, M.S.

US Army Research Institute of Environmental Medicine
Natick, Massachusetts, United States
KP

Kimberly N. Panik

Oak Ridge Institute for Science and Education, United States
JM

Julia Michalak

Oak Ridge Institute for Science and Education, United States
EH

Emily E. Howard, PhD

Nutrition Physiologist
US Army Research Institute of Environmental Medicine
Natick, Massachusetts, United States
JM

James P. McClung

U.S. Army Research Institute of Environmental Medicine
LM

Lee M. Margolis, PhD, RD

U.S. Army Research Institute of Environmental Medicine

Objectives: Military operations often result in high daily energy expenditures and suboptimal energy intake resulting in severe energy deficits. Alterations in circulating microRNA (c-miRNA) profiles following periods of exercise-induced energy deficits provides insight into underlying adaptations to targeted biological processes at the cellular level. Whether c-miRNA profiles are altered during arduous Marine amphibious training (AMPHIB) is unknown.

Methods: Twelve male Marines (mean ± SD; body mass: 83.4 ± 6.7 kg, height: 179.0 ± 5.9 cm) participating in 10-day AMPHIB in Key West, FL (30 ± 1°C, 75 ± 7% humidity) enrolled in this observational study. Energy expenditure (D₂¹⁸O) was assessed daily. Energy intake was estimated from 24-hour observation of dietary intake on day 5 of the training. c-miRNA (RT-qPCR microarray) were measured in fasted/rested serum samples collected before (PRE) and after (POST) AMPHIB. Stepwise discriminate analysis was conducted on significantly different c-miRNA to determine those most sensitive to changes over time. Bioinformatics (miRTargetLink 2.0) analysis were used to identify function of the most significant c-miRNA.

Results: Energy expenditure was 5333 ± 570 kcal/d and energy intake was 3953 ± 584 kcal/d, resulting in an estimated energy balance of -1380 ± 459 kcal/d during AMPHIB. Body mass decreased (P < 0.05) 1.0 ± 1.1 kg from PRE to POST. Eighteen c-miRNA decreased (P < 0.05) at POST compared with PRE. Of these 18 c-miRNA, miR-133b and miR-451a were the most sensitive (P < 0.05) to changes over time and were identified to target genes associated with inflammation (MMP-9) and protein turnover (AKT1).

Conclusions: These data indicate that 10 days of arduous Marine training downregulates the expression of c-miRNA that target inflammation and protein turnover. These alterations in c-miRNA and their targets in the current study is novel information that may provide greater insight into physiological adaptations to military operations.

Funding Sources: Marine Special Operations Command (MARSOC); author’s views not official Army or DoD policy.