Dynamics of fat cell turnover in humans.
Obesity is increasing in an epidemic manner in most countries and constitutes a public health problem by enhancing the risk for cardiovascular disease and metabolic disorders such as type 2 diabetes. Owing to the increase in obesity, life expectancy may start to decrease in developed countries for the first time in recent history. The factors determining fat mass in adult humans are not fully understood, but increased lipid storage in already developed fat cells (adipocytes) is thought to be most important. Here we show that adipocyte number is a major determinant for the fat mass in adults. However, the number of fat cells stays constant in adulthood in lean and obese individuals, even after marked weight loss, indicating that the number of adipocytes is set during childhood and adolescence. To establish the dynamics within the stable population of adipocytes in adults, we have measured adipocyte turnover by analysing the integration of 14C derived from nuclear bomb tests in genomic DNA. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index. Neither adipocyte death nor generation rate is altered in early onset obesity, suggesting a tight regulation of fat cell number in this condition during adulthood. The high turnover of adipocytes establishes a new therapeutic target for pharmacological intervention in obesity.
Spalding
Kirsty L
KL
Department of Cell and Molecular Biology, Karolinska Institute, SE-171 77 Stockholm, Sweden. kirsty.spalding@ki.se
Arner
Erik
E
Westermark
Pål O
PO
Bernard
Samuel
S
Buchholz
Bruce A
BA
Bergmann
Olaf
O
Blomqvist
Lennart
L
Hoffstedt
Johan
J
Näslund
Erik
E
Britton
Tom
T
Concha
Hernan
H
Hassan
Moustapha
M
Rydén
Mikael
M
Frisén
Jonas
J
Arner
Peter
P
D017667:Adipocytes / Q000166:cytology*; D000273:Adipose Tissue / Q000033:anatomy & histology / Q000166:cytology*; D000328:Adult; D015992:Body Mass Index; D002250:Carbon Radioisotopes; D002452:Cell Count; D016923:Cell Death; D048429:Cell Size; D006801:Humans; D009765:Obesity / Q000473:pathology; D013234:Stem Cells / Q000166:cytology*; D015431:Weight Loss
D002250:Carbon Radioisotopes