Association between interleukin-15 and obesity: interleukin-15 as a potential regulator of fat mass.
OBJECTIVE
IL-15 decreases lipid deposition in preadipocytes and decreases the mass of white adipose tissue in rats, indicating that IL-15 may take part in regulating this tissue. IL-15 is expressed in human skeletal muscle and skeletal muscle may be a source of plasma IL-15 and in this way regulate adipose tissue mass.


METHODS
The relation between skeletal muscle IL-15 mRNA expression, plasma IL-15, and adipose tissue mass was studied in 199 humans divided into four groups on the basis of obesity and type 2 diabetes. Furthermore, using a DNA electrotransfer model, we assessed the effect of IL-15 overexpression in skeletal muscle of mice.


RESULTS
In humans, multiple regression analysis showed a negative association between plasma IL-15 and total fat mass (P<0.05), trunk fat mass (P<0.01), and percent fat mass (P<0.05), independent of type 2 diabetes. Negative associations were also found between muscle IL-15 mRNA and obesity parameters. IL-15 overexpression in skeletal muscle of mice reduced trunk fat mass but not sc fat mass.


CONCLUSIONS
Our results indicate that IL-15 may be a regulator of trunk fat mass.
Nielsen
Anders Rinnov
AR
Department of Infectious Diseases Rigshospitalet, Centre of Inflammation and Metabolism, University of Copenhagen, Section 7641, Blegdamsvej 9, DK-2100 Copenhagen, Denmark. rinnov@gmail.com
Hojman
Pernille
P
Erikstrup
Christian
C
Fischer
Christian Philip
CP
Plomgaard
Peter
P
Mounier
Remi
R
Mortensen
Ole Hartvig
OH
Broholm
Christa
C
Taudorf
Sarah
S
Krogh-Madsen
Rikke
R
Lindegaard
Birgitte
B
Petersen
Anne Marie Winther
AM
Gehl
Julie
J
Pedersen
Bente Klarlund
BK
D017667:Adipocytes / Q000502:physiology; D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000502:physiology; D000818:Animals; D001823:Body Composition; D015992:Body Mass Index; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology; D005260:Female; D005951:Glucose Tolerance Test; D006706:Homeostasis; D006801:Humans; D019409:Interleukin-15 / Q000097:blood / Q000235:genetics / Q000502:physiology*; D008297:Male; D051379:Mice; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology / Q000503:physiopathology; D009765:Obesity / Q000503:physiopathology*; D010809:Physical Fitness; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
D019409:Interleukin-15; D012333:RNA, Messenger