Dietary vitamin B6 supplementation attenuates hypertension in spontaneously hypertensive rats

In spontaneously hypertensive rats (SHRs) excess endogenous aldehydes bind sulfhydryl groups of membrane proteins, altering membrane Ca²⁺ channels, increasing cytosolic free calcium and blood pressure. N-acetyl cysteine normalizes elevated blood pressure in SHRs by binding excess endogenous aldehydes. It is known that dietary vitamin B6 supplementation can increase the level of endogenous cysteine. Our objective was to investigate whether a dietary supplementation of vitamin B6 can prevent hypertension and associated changes in SHRs. Starting at 7 weeks of age, animals were divided into three groups of six animals each. Animals in WKY-control group and SHR-control group were given a normal vitamin B6 diet; and SHR-vitamin B6 group, a high vitamin B6 diet (20 times the recommended dietary intake; RDA) for the next 14 weeks. After 14 weeks, systolic blood pressure, platelet Ca²⁺]_i and liver, kidney and aortic aldehyde conjugates were significantly higher in SHR controls compared to WKY controls. These animals also showed smooth muscle cell hyperplasia in the small arteries and arterioles of the kidneys. Dietary vitamin B6 supplementation attenuated the increase in systolic blood pressure, tissue aldehyde conjugates and associated changes. These results further support the hypothesis that aldehydes are involved in increased systolic blood pressure in SHRs and suggest that vitamin B6 supplementation may be an effective antihypertensive.