Concordance of in vivo microdialysis and in vitro techniques in the studies of adipose tissue metabolism.
BACKGROUND
Adipose tissue metabolism can be investigated directly in vivo by microdialysis and indirectly in vitro using isolated adipocytes. The in vitro studies are relatively easy to make and they give information about specific tissue metabolism. The in vivo studies, on the other hand, are supposed to give relevant data about tissue physiology interacting with other metabolic systems at the body level.


OBJECTIVE
To investigate the concordance between the results on responsiveness to stimulation of lipolysis from in vivo microdialysis and in vitro isolated adipocytes.


METHODS
Altogether 22 massively obese otherwise healthy subjects (seven men and 15 women, age 41 (26-55) y, BMI 51.5 (37.5-73.9)kg/m2, mean (range)) going through the gastric banding operation participated in the study.


METHODS
The microdialysis study was done after an overnight fast at rest. Lipolysis was stimulated with isoprenaline that was perfused into the subcutaneous abdominal adipose tissue. Local blood flow was estimated by ethanol dilution method. Adipose tissue biopsy for the in vitro study was taken from subcutaneous abdominal region during the operation. Lipolysis in freshly isolated adipocytes was stimulated with different concentrations of adrenaline or isoprenaline.


RESULTS
Significant positive correlations were observed between the values of relative stimulation of lipolysis in isolated adipocytes and in the microdialysis study. These correlations improved after correcting for cell size or fat mass.


CONCLUSIONS
The microdialysis study in vivo and lipolysis assay with isolated adipocytes in vitro provide concordant and complementary information of adipose tissue metabolism in the same individual.
Kolehmainen
M
M
Department of Clinical Nutrition, University of Kuopio and Kuopio University Hospital, Finland. Marjukka.Kolehmainen@uku.fi
Ohisalo
J J
JJ
Kaartinen
J M
JM
Tuononen
V
V
Pääkkönen
M
M
Poikolainen
E
E
Alhava
E
E
Uusitupa
M I
MI
D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism*; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000328:Adult; D001823:Body Composition; D002478:Cells, Cultured; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D005951:Glucose Tolerance Test; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008066:Lipolysis / Q000502:physiology*; D008297:Male; D017551:Microdialysis / Q000379:methods; D008875:Middle Aged; D009767:Obesity, Morbid / Q000503:physiopathology*; D013223:Statistics as Topic
D000318:Adrenergic beta-Agonists; D007545:Isoproterenol; D005990:Glycerol; D004837:Epinephrine