The protective effect of irbesartan in rats fed a high fat diet is associated with modification of leptin-adiponectin imbalance.
OBJECTIVE
It has been shown that the renin-angiotensin system participates in the development of the metabolic syndrome. This study aimed to show whether the angiotensin II type 1 receptor blocker, irbesartan, exerts a protective effect against metabolic and cardiovascular abnormalities in rats fed a high fat diet (HFD).


METHODS
Wistar rats (n = 30) were divided into three groups: (1) rats fed a standard diet for 7 weeks were used as a control group; (2) rats fed a HFD (33.5% fat) for 7 weeks; and (3) rats fed a HFD (33.5% fat) treated with irbesartan (0.1 mg/kg per day) for 7 weeks. Body weight, white and brown adipose tissue weight, plasma concentrations and protein expression of leptin and adiponectin in white adipose tissue, and glucose metabolism were investigated. Vascular reactivity in aortic rings and heart function were also evaluated.


RESULTS
HFD rats showed increased (P < 0.05) body, epididymal and lumbar adipose tissue weights, but did not experience a change in brown adipose tissue weight. Irbesartan attenuated (P < 0.05) all of these parameters, but increased brown adipose tissue weight. The leptin/adiponectin ratio of plasma concentrations and protein expression in lumbar adipose tissue increased (P < 0.05) in HFD rats, and were normalized by irbesartan. Along with these changes, irbesartan improved (P < 0.05) insulin sensitivity and exaggerated responses to angiotensin I and II in the aorta.


CONCLUSIONS
Irbesartan reduced body and white adipose tissue weights, improved glucose metabolism and vascular function in the aorta. The correction of leptin-adiponectin imbalance may be an important mechanism participating in the protective effect of irbesartan in HFD rats.
de las Heras
Natalia
N
Department of Physiology, Facultad de Medicina, Universidad Complutense, Madrid, Spain.
Martín-Fernández
Beatriz
B
Miana
Maria
M
Ballesteros
Sandra
S
Oubiña
Maria Pilar
MP
López-Farré
Antonio J
AJ
Cachofeiro
Victoria
V
Lahera
Vicente
V
D052242:Adiponectin / Q000096:biosynthesis*; D000273:Adipose Tissue / Q000378:metabolism; D047228:Angiotensin II Type 1 Receptor Blockers / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D001011:Aorta / Q000473:pathology; D001713:Biphenyl Compounds / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D000077405:Irbesartan; D020738:Leptin / Q000096:biosynthesis*; D008297:Male; D024821:Metabolic Syndrome / Q000378:metabolism; D008954:Models, Biological; D051381:Rats; D017208:Rats, Wistar; D012084:Renin-Angiotensin System; D013777:Tetrazoles / Q000494:pharmacology*
D052242:Adiponectin; D047228:Angiotensin II Type 1 Receptor Blockers; D001713:Biphenyl Compounds; D020738:Leptin; D013777:Tetrazoles; D005947:Glucose; D000077405:Irbesartan