Heart conditioned medium promotes central cholinergic regeneration in vivo

The aim of the present study was to evaluate the effect of a proposed cholinergic growth factor, heart conditioned medium (HCM), on the regeneration of the cholinergic septo-hippocampal pathway in rats. At 0, 4, 8 and 16 days after mechanical injury to septo-hippocampal axons, animals received either repeated intraseptal injections of HCM or control vehicles. Recovery of choline acetyltransferase (CAT) activity in iris implants placed in the hippocampus was used as an index of cholinergic regeneration. The results indicate that CAT activity in iris implants from animals receiving HCM was significantly greater than in control implants. Thus, this is the first report of the in vivo activity of heart conditioned medium as a cholinergic growth factor.