The trafficking of
glycerol from adipose and hepatic tissue is mainly mediated by 2
aquaporin channel
proteins: AQP7 and AQP9, respectively. In rodents, both
aquaporins were found to act in a coordinated manner. The aim was to study the relationship between adipose AQP7 and hepatic AQP9
messenger RNA expression and the presence of
glucose abnormalities simultaneously in
morbid obesity. Adipose tissue (subcutaneous [SAT] and visceral [VAT]) and liver biopsies from the same patient were obtained during
bariatric surgery in 30 (21 male and 9 female) morbidly obese subjects. Real-time quantification of AQP7 in SAT and VAT and hepatic AQP9 gene expression were performed. A 75-g oral
glucose tolerance test was performed in all subjects. The homeostasis model assessment of
insulin resistance and lipidic profile were also determined. Visceral adipose tissue AQP7 expression levels were significantly higher than SAT AQP7 (P = .009). Subcutaneous adipose tissue AQP7 positively correlated with both VAT AQP7 and hepatic AQP9
messenger RNA expression (r = 0.44, P = .013 and r = 0.45, P = .012, respectively). The correlation between SAT AQP7 and liver AQP9 was stronger in intolerant and
type 2 diabetes mellitus subjects (r = 0.602, P = .011). We have found no differences in compartmental AQP7 adipose tissue distribution or AQP9 hepatic gene expression according to
glucose tolerance classification. The present study provides, for the first time, evidence of coordinated regulation between adipose
aquaglyceroporins, with a greater expression found in visceral fat, and between subcutaneous adipose AQP7 and hepatic AQP9 gene expression within the context of human
morbid obesity.