Hypocholesterolemic effect of Eubacterium coprostanoligenes ATCC 51222 in rabbits

Recently, a unique bacterium, Eubacterium coprostanoligenes ATCC 51222, that reduces cholesterol to coprostanol was isolated. Because coprostanol is absorbed poorly, it was hypothesized that oral administration of Eu. coprostanoligenes might decrease cholesterol concentration in blood because the micro-organisms will decrease the absorption of endogenous and dietary cholesterol by conversion to coprostanol. To test the hypothesis, three adult New Zealand White rabbits received 4 ml of Eu. coprostanoligenes suspension (ca 2 x 10(7) cells ml-1) daily per os for 10 d; three other adult New Zealand White rabbits received the same dosage of boiled bacterial suspension. Plasma cholesterol concentration of experimental rabbits (183.3 +/- 11.0 mg dl-1, mean +/- S.E.) was significantly lower (P < 0.001) than that of controls (248.8 +/- 12.3 mg dl-1, mean +/- S.E.). The coprostanol-to-cholesterol ratios in contents of digestive tracts of experimental rabbits were greater than those of controls. The data indicate that oral administration of Eu. coprostanoligenes caused a significant hypocholesterolemic effect in rabbits and that this effect can be explained by the conversion of cholesterol to coprostanol in the intestine.