Influence of nicotinic acid, niceritrol and β-pyridylcarbinol on experimental hyperlipidemia and atherosclerosis in mini-pigs

Abstract

A study was undertaken to test for suitable conditions for examining the hypolipidemic and antiatherosclerotic actions of nicotinic acid, niceritrol and β-pyridylcarbinol in hypercholesterolemic mini-pigs. Hypercholesterolemia was produced in 50 female pigs by adding 11% dried egg yolk +0.5–0.75% cholesterol to their diet for 12–19 months. The animals were divided into 3 groups according to the response of their initial plasma cholesterol value (“low” ∼500; “medium” ∼700; “high” ∼1000 mg/100 ml). The plasma triglycerideconcentrations were increased in the latter two groups but not in the former. Most of the cholesterol was present in the LDL ( d = 1.006-1.063). In the medium group 0.5–0.75% of β-pyridylcarbinol or niceritrol in the diet produced a long-lasting and significant decrease of the plasma cholesterol concentration by about 150 mg/100 ml, predominantly by reducing the raised plasma LDL, whereas nicotinic acid produced only a transient decrease. In the “low”-cholesterol group, β-pyridylcarbinol and niceritrol also only produced a transient decrease. Atherosclerotic lesions developed in the coronary arteries and abdominal aorta of the “medium”- and “low”-cholesterol groups. Most of the increase of cholesterol esters took place in the intima. Niceritrol and β-pyridylcarbinol markedly reduced the lipid-infiltrated area of the abdomimal aorta and the accumulation of free and esterified cholesterol in the abdominal aorta and coronary arteries, whereas nicotinic acid was less effective in the latter respect. Part of the antiatherosclerotic action of β-pyridylcarbinol and niceritrol was due to their hypocholesterolemic effect. A more direct action on the vascular wall was probably also involved.