Hyperhomocysteinemia and arteriosclerosis: historical perspectives

Early concepts of the origin of arteriosclerosis were introduced in the 19th century by Rokitansky and Virchow, who described mural thrombosis, inflammatory damage to arterial intima, increased intimal permeability to plasma, mucoid degeneration of arterial wall, deposition of plasma lipids in plaques, and fibrosis and calcification of plaques. Experimental production of arteriosclerosis by feeding animal foods to rabbits was attributed to protein intoxication by Ignatowsky in 1908 and to dietary cholesterol by Anitschkow in 1913. Newburgh confirmed the protein hypothesis in 1915–1925 but failed to identify which amino acid produced plaques because methionine (1922) and homocysteine (1932) had not yet been discovered. Cases of homocystinuria from inherited deficiency of cystathionine synthase were found to be associated with thrombosis and vascular disease in 1964. The index case of methionine synthase deficiency (cobalamin C disease) was found by McCully in 1969 to be associated with arteriosclerosis, leading to the homocysteine theory of arteriosclerosis. The theory explains experimental arteriosclerosis by deficiency of vitamin B

Comparative Effects of Vitamin K2 and Estradiol on Experimental Arteriosclerosis with Diabetes Mellitus

In order to further investigate the radical scavenging and anti-arteriosclerotic activities of vitamin K2 and estradiol, the comparative effects of vitamin K2 and estradiol on aortic calcium (Ca) and inorganic phosphorus (P) levels in the aorta and the elastin fraction (fr.) were investigated in male rats after experimental arteriosclerosis with diabetes mellitus was induced by vitamin D2 and radical producing substance, streptozotocin (STZ). Pharmacological dose of vitamin K2 (100 mg/kg b.w.) and medical dose of estradiol (83 mug/kg b.w.) suppressed the increased serum glucose, and vitamin K2 and estradiol increased the decrease in serum insulin. Moreover, vitamin K2 and estradiol inhibited the increase of Ca and P in the aorta and the elastin fr. Vitamin K2 and estradiol decreased the increase in serum lipid peroxide (LPO). It is suggested that both the pharmacological dose of vitamin K2 and medical dose of estradiol suppressed development of arteriosclerosis associated with diabetes mellitus, owing to radical scavenging activity of vitamin K2, and estradiol.

Comparative Effects of Vitamin K2 and Vitamin E on Experimental Arteriosclerosis

The comparative effects of vitamin K2 and vitamin E on aortic calcium (Ca) and inorganic phosphorus (P) levels in the aorta and the elastin fraction (fr.) were investigated in male rats after experimental arteriosclerosis was induced by vitamin D2 with atherogenic diet. Both vitamin K2 (100 mg/kg b.w.) and vitamin E (40 mg/kg b.w.) inhibited the increase of Ca and P in the aorta and the elastin fr. from the arteriosclerotic rats. Vitamin K2 (50 mg/kg b.w.) also suppressed the deposition of Ca and P in the aorta, but there was no change due to vitamin K3 or geranylgeraniol (side chain of vitamin K2) administration. Both vitamin K2 and vitamin E showed lipid radical scavenging activity in the in vitro experiment. However, neither vitamin K3 nor geranylgeraniol exhibited anti-arteriosclerotic or radical scavenging activity under the above experimental conditions. It is suggested that vitamin K2 and vitamin E promoted an antiarteriosclerotic effect by radical scavenging activity. These actions of vitamin K2 are required in the structure of 2-methylnaphthoquinone and its side chain (geranylgeraniol).