Active individuals have high mitochondrial content and oxidative markers in their abdominal subcutaneous adipose tissue.
OBJECTIVE
Exercise training (training) effects on white adipose tissue (WAT) thermogenic and oxidative capacities in humans are inconclusive. This study aimed to investigate whether an active lifestyle is characterized by thermogenic and/or oxidative transcriptional markers in human WAT.


METHODS
In vivo maximal muscle ATP synthetic rates (ATPmax) were measured by31P-MRS, body composition by DXA, and peak oxygen uptake (VO2peak) by cycle ergometry in active (n = 7) and sedentary (SED) individuals before and after 3 weeks of training (n = 9, SED only). mRNA expressions of brown adipose and β-oxidation markers, as well as mitochondrial DNA content (mtDNA), were measured by qRT-PCR and qPCR, respectively, in WAT.


RESULTS
ATPmax and VO2peak were higher in active versus SED individuals. Following training in SED individuals, ATPmax and VO2peak increased. Proliferator-activated receptor gamma coactivator-1α and carnitine palmitoyltransferase-1β gene expressions and mtDNA content were significantly higher in WAT of active versus SED individuals before training. mRNA contents of brown and beige-specific markers were not different between cohorts. Training effectively increased ATPmax and VO2peak but had no effect on mtDNA content or expressions of genes that regulate thermogenic and oxidative capacities in WAT.


CONCLUSIONS
Results indicate that an active lifestyle is characterized by elevated mitochondrial content and oxidative, not thermogenic, markers of WAT.
Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida, USA.
Maria F
MF
Pino
Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida, USA.
Stephanie A
SA
Parsons
Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida, USA.|Sanford Burnham Prebys Medical Discovery Institute, Center for Clinical and Molecular Origins of Disease, Orlando, Florida, USA.
Steven R
SR
Smith
Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida, USA.|Sanford Burnham Prebys Medical Discovery Institute, Center for Clinical and Molecular Origins of Disease, Orlando, Florida, USA.
Lauren M
LM
Sparks
D000255:Adenosine Triphosphate / Q000032:analysis; D002001:Adipose Tissue, Brown / Q000737:chemistry; D052436:Adipose Tissue, White / Q000378:metabolism; D050154:Adiposity; D001823:Body Composition; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000032:analysis; D015444:Exercise; D006801:Humans; D008019:Life Style; D008928:Mitochondria / Q000378:metabolism / Q000648:ultrastructure; D009765:Obesity / Q000378:metabolism; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D012333:RNA, Messenger / Q000032:analysis; D050507:Subcutaneous Fat, Abdominal / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D022722:Thermogenesis / Q000235:genetics
D004272:DNA, Mitochondrial; D012333:RNA, Messenger; D000255:Adenosine Triphosphate; D002334:Carnitine O-Palmitoyltransferase