Glycobiology Advance Access published online on May 5, 2008
Glycobiology, doi:10.1093/glycob/cwn034
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Glycation does not modify bovine serum albumin (BSA)-induced reduction of rat aortic relaxation. The response to glycated and non-glycated BSA is lost in metabolic syndrome
* Department of Physiology, x Department of Pathology, Instituto Nacional de Cardiología "Ignacio Chávez", Mexico City 14080, Mexico
Department of Reproductive Biology, Instituto Nacional de Ciencias Médicas y de la Nutrición "Salvador Zubirán"
Corresponding author: Verónica Guarner Ph.D., Departamento de Fisiología, Instituto Nacional de Cardiología "Ignacio Chávez", Juan Badiano 1, 14080, Tlalpan, México D.F., tel 55 55 73 29 11 ext 1222 fax: 55 55 73 09 26, email: vguarner{at}yahoo.com
Received on September 26, 2007; accepted on April 25, 2008
The effects of non-glycated bovine serum albumin (BSA) and advanced glycosylation end products of BSA (AGE-BSA) on vascular responses of control and metabolic syndrome (MS) rats characterized by hypertriglyceridemia, hypertension, hyperinsulinemia and insulin resistance were studied. Albumin and in vitro prepared AGE-BSA have vascular effects; however, recent studies indicate that some effects of in vitro prepared AGEs are due to the conditions in which they were generated. We produced AGEs by incubating glucose with BSA for 60 days under sterile conditions in darkness and at 37°C. To develop MS rats, male Wistar animals were given 30% sucrose in drinking water since weanling. Six months old animals were used. Blood pressure, insulin, triglycerides and serum albumin were increased in MS rats. Contraction of aortic rings elicited with norepinephrine was stronger. There were no effects of non-glycated BSA or AGE-BSA on contractions in control or MS rats; however, both groups responded to L-NAME, an inhibitor of nitric oxide synthesis. Arterial relaxation induced using acetylcholine was smaller in MS rats. Non-glycated BSA and AGE-BSA significantly diminished relaxation in a 35% in the control group but the decrease was similar when using non-glycated BSA and AGE-BSA. This decrease was not present in the MS rats and was not due to increased RAGEs or altered biochemical characteristics of BSA. In conclusion both BSA and AGE-BSA inhibit vascular relaxation in control artic rings. In MS rats the effect is lost possibly due to alterations in endothelial cells that are a consequence of the illness.
Key words: BSA / AGE-BSA / vascular relaxation / metabolic syndrome