A
proline-rich
polypeptide complex (PRP) subsequently known as ColostrininTM was found for the first time in ovine colostrum as a fraction accompanying colostral
IgG2. Subsequently, similar
polypeptides were found in human, bovine and caprine colostrum. PRP is a complex of
peptides of molecular masses from 500 to 3000 Da. It contains 25%
proline residues and 40% hydrophobic
amino acids. It is not species specific, and is active both in vivo and in vitro. PRP possesses immunoregulatory properties, including effects on humoral and cellular immune responses, shows regulatory activity in Th1 and Th2
cytokine induction, and has the ability to inhibit the overproduction of
reactive oxygen species and
nitric oxide. PRP has also shown psychotropic properties. Both immunoregulatory and psychotropic properties suggest potential clinical use of PRP for
neurodegenerative disorders. Beneficial effects of PRP/
Colostrinin in the case of
Alzheimer's disease were shown in double-blind placebo-controlled trials, in long-term open-label studies and in multicenter clinical trials. A very important property of PRP/
Colostrinin and one of its components, a nonapeptide (NP), is the prevention of Aβ aggregation and the disruption of aggregates already formed. Moreover, PRP has been found to modulate neurite outgrowth, suppress uncontrolled activation of cells, and reduce 4-HNE-mediated cellular damage.
Biological response modifying activity of PRP/
Colostrinin can play an important role in its use in the treatment of
Alzheimer's disease and suggests its application beyond
neurodegenerative disorders.