PMID- 33772787
OWN - NLM
STAT- MEDLINE
DCOM- 20210707
LR  - 20220531
IS  - 1469-7793 (Electronic)
IS  - 0022-3751 (Linking)
VI  - 599
IP  - 11
DP  - 2021 Jun
TI  - Carbohydrate improves exercise capacity but does not affect subcellular lipid 
      droplet morphology, AMPK and p53 signalling in human skeletal muscle.
PG  - 2823-2849
LID - 10.1113/JP281127 [doi]
AB  - KEY POINTS: Muscle glycogen and intramuscular triglycerides (IMTG, stored in 
      lipid droplets) are important energy substrates during prolonged exercise. 
      Exercise-induced changes in lipid droplet (LD) morphology (i.e. LD size and 
      number) have not yet been studied under nutritional conditions typically adopted 
      by elite endurance athletes, that is, after carbohydrate (CHO) loading and CHO 
      feeding during exercise. We report for the first time that exercise reduces IMTG 
      content in both central and peripheral regions of type I and IIa fibres, 
      reflective of decreased LD number in both fibre types whereas reductions in LD 
      size were exclusive to type I fibres. Additionally, CHO feeding does not alter 
      subcellular IMTG utilisation, LD morphology or muscle glycogen utilisation in 
      type I or IIa/II fibres. In the absence of alterations to muscle fuel selection, 
      CHO feeding does not attenuate cell signalling pathways with regulatory roles in 
      mitochondrial biogenesis. ABSTRACT: We examined the effects of carbohydrate (CHO) 
      feeding on lipid droplet (LD) morphology, muscle glycogen utilisation and 
      exercise-induced skeletal muscle cell signalling. After a 36 h CHO loading 
      protocol and pre-exercise meal (12 and 2 g kg(-1) , respectively), eight trained 
      males ingested 0, 45 or 90 g CHO h(-1) during 180 min cycling at lactate 
      threshold followed by an exercise capacity test (150% lactate threshold). Muscle 
      biopsies were obtained pre- and post-completion of submaximal exercise. Exercise 
      decreased (P < 0.01) glycogen concentration to comparable levels ( approximately 700 to 
      250 mmol kg(-1) DW), though utilisation was greater in type I ( approximately 40%) versus type 
      II fibres ( approximately 10%) (P < 0.01). LD content decreased in type I ( approximately 50%) and type IIa 
      fibres ( approximately 30%) (P < 0.01), with greater utilisation in type I fibres (P < 0.01). 
      CHO feeding did not affect glycogen or IMTG utilisation in type I or II fibres 
      (all P > 0.05). Exercise decreased LD number within central and peripheral 
      regions of both type I and IIa fibres, though reduced LD size was exclusive to 
      type I fibres. Exercise induced (all P < 0.05) comparable AMPK(Thr172) ( approximately 4-fold), 
      p53(Ser15) ( approximately 2-fold) and CaMKII(Thr268) phosphorylation ( approximately 2-fold) with no effects 
      of CHO feeding (all P > 0.05). CHO increased exercise capacity where 90 g h(-1) 
      (233 +/- 133 s) > 45 g h(-1) (156 +/- 66 s; P = 0.06) > 0 g h(-1) (108 +/- 54 s; 
      P = 0.03). In conditions of high pre-exercise CHO availability, we conclude CHO 
      feeding does not influence exercise-induced changes in LD morphology, glycogen 
      utilisation or cell signalling pathways with regulatory roles in mitochondrial 
      biogenesis.
CI  - (c) 2021 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd 
      on behalf of The Physiological Society.
FAU - Fell, J Marc
AU  - Fell JM
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
FAU - Hearris, Mark A
AU  - Hearris MA
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
FAU - Ellis, Daniel G
AU  - Ellis DG
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
FAU - Moran, James E P
AU  - Moran JEP
AUID- ORCID: 0000-0003-3680-8848
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
FAU - Jevons, Emily F P
AU  - Jevons EFP
AUID- ORCID: 0000-0001-8902-3708
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
FAU - Owens, Daniel J
AU  - Owens DJ
AUID- ORCID: 0000-0002-1908-8677
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
FAU - Strauss, Juliette A
AU  - Strauss JA
AUID- ORCID: 0000-0001-7175-2494
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
FAU - Cocks, Matthew
AU  - Cocks M
AUID- ORCID: 0000-0003-1671-8714
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
FAU - Louis, Julien B
AU  - Louis JB
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
FAU - Shepherd, Sam O
AU  - Shepherd SO
AUID- ORCID: 0000-0001-6292-1356
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
FAU - Morton, James P
AU  - Morton JP
AUID- ORCID: 0000-0003-2776-2542
AD  - Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores 
      University, Byrom Street, Liverpool, L3 3AF, UK.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20210503
PL  - England
TA  - J Physiol
JT  - The Journal of physiology
JID - 0266262
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (TP53 protein, human)
RN  - 0 (Tumor Suppressor Protein p53)
RN  - EC 2.7.11.31 (AMP-Activated Protein Kinases)
SB  - IM
CIN - J Physiol. 2021 Sep;599(18):4243-4245. PMID: 34292630
MH  - *AMP-Activated Protein Kinases
MH  - Dietary Carbohydrates
MH  - Exercise Tolerance
MH  - Humans
MH  - *Lipid Droplets
MH  - Male
MH  - Muscle, Skeletal
MH  - Tumor Suppressor Protein p53
OTO - NOTNLM
OT  - glycogen
OT  - intramuscular triglyceride
OT  - vastus lateralis
EDAT- 2021/03/28 06:00
MHDA- 2021/07/08 06:00
CRDT- 2021/03/27 17:25
PHST- 2020/12/14 00:00 [received]
PHST- 2021/03/22 00:00 [accepted]
PHST- 2021/03/28 06:00 [pubmed]
PHST- 2021/07/08 06:00 [medline]
PHST- 2021/03/27 17:25 [entrez]
AID - 10.1113/JP281127 [doi]
PST - ppublish
SO  - J Physiol. 2021 Jun;599(11):2823-2849. doi: 10.1113/JP281127. Epub 2021 May 3.