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Endothelial function in healthy younger and older hyperhomocysteinemic subjects
Sandra Hirsch1, Pía de la Maza, Laura Mendoza
1INTA, Institute of Nutrition and Food Technology, University of Chile, Macul 5540, Casilla 138-11, Santiago, Chile. shirsch@uec.inta.uchile.cl
Objectives:
To compare endothelium-dependent vasomotor response in healthy younger and older subjects without classic cardiovascular risk factors, with high and normal fasting homocysteine (tHcy) levels.
Design:
We compared endothelium-dependent vasodilatation, using ultrasound, in healthy younger (aged 18-40) and older (> or =70) people with normal (<13 micromol/L) and high (>15 micromol/L) tHcy levels. Exclusion criteria were smoking, personal history of cardiovascular disease, hypertension, chronic diseases, vitamin intake, obesity, abnormal serum lipids levels, and creatinine higher than 130 micromol/L.
Setting:
Research laboratory.
Measurements:
In addition to tHcy levels, serum folate and vitamin B12 levels were measured.
Results:
We studied 17 younger and 12 older hyperhomocysteinemic subjects and respective aged-matched normohocysteinemic subjects. Endothelium-dependent vasodilatation was lower in the hyperhomocysteinemic older people (P <.01) than in all younger subjects and in normohomocysteinemic older people. Serum vitamin B12 levels were higher in younger and older normal controls. Folic acid levels were higher in younger controls and in both older groups.
Conclusions:
This study shows an effect of high circulating tHcy on vascular reactivity in older people. Because serum levels of tHcy are associated with nutritional status of vitamin B12 and folic acid, prospective studies are necessary to demonstrate the effects of a long-term nutritional supplementation with vitamins on vascular function and global cardiovascular risk.