Transforming growth factor-beta1 levels in hypertensive patients: association with body mass index and leptin.
BACKGROUND
Transforming growth factor-beta1 (TGF-beta1) has been demonstrated to be overexpressed in hypertension. Leptin, an adipocyte product, has been shown to play a role in obesity-related hypertension and in vitro studies demonstrated a biologic interaction between leptin and TGF-beta1. Thus, we evaluate a possible in vivo association between TGF-beta1, body mass index (BMI), and leptin circulating levels in hypertensive subjects.


METHODS
Blood samples for fasting leptin and TGF-beta1, were evaluated in 29 overweight, 46 obese, and 29 nonobese hypertensive patients before and after a 12-week calorie-restricted diet. Monocyte cultures were used for in vitro experiments.


RESULTS
Transforming growth factor-beta1 was significantly elevated in hypertensive obese patients (n = 46) as compared with TGF-beta1 levels of hypertensive patients with normal BMI (n = 29) (8. 9 +/- 3 ng/mL v 4.4 +/- 2; P < .001). The circulating levels of TGF-beta1 were associated with BMI and leptin levels in an univariate analysis (r = 0.59, P < .0001; r = 0.62, P < .0001, respectively) and these associations were still present after stepwise multivariate analysis. Weight loss of 10% produced a parallel decrease in TGF-beta1 (from 8.9 +/- 3 ng/mL to 5.3 +/- 2.8 ng/mL; P < .01) and leptin levels (from 30 +/- 24 ng/mL to 17 +/- 14; P < .05). In vitro experiments showed that leptin is able to induce a dose-dependent increase in TGF-beta1 production and mRNA expression in human monocyte cultures.


CONCLUSIONS
Our data indicate that TGF-beta1 levels are positively associated with BMI and leptin levels in hypertensive patients and suggest that adipose tissue may be an important determinant of TGF-beta1 levels possibly by a leptin-dependent pathway.
Porreca
Ettore
E
Dipartimento di Medicina e Scienze dell'Invecchiamento, University of Chietiand, Chieti, Italy. eporreca@unich.it
Di Febbo
Concetta
C
Vitacolonna
Ester
E
Baccante
Giovanna
G
Di Castelnuovo
Augusto
A
Angelini
Antonio
A
Febo
Francesca
F
Di Nisio
Marcello
M
Cuccurullo
Franco
F
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D005260:Female; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D006973:Hypertension / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D066298:In Vitro Techniques; D020738:Leptin / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D012333:RNA, Messenger / Q000235:genetics; D012044:Regression Analysis; D016212:Transforming Growth Factor beta / Q000097:blood* / Q000235:genetics; D015431:Weight Loss / Q000502:physiology
D020738:Leptin; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta