[Atelocollagen as a potential carrier of therapeutics]

Collagen is a very abundant protein that makes up about 25% of the total protein in animal organisms. Of the 28 types of collagen described so far, type I is the most common. Applying collagen in medical treatment is dangerous and may be harmful to patients due to its high immunoreactivity and the risk of contamination with viruses or prions. The immunogenicity of collagen I can be significantly reduced by digestion with pepsin, resulting in the release of telopeptides containing mostly antigenic epitopes. The major product of the digestion is called atelocollagen, which was used for the first time in tissue engineering already in the 1970s. Recent data indicate that due to its rare properties, such as low immunogenicity, liquid state at 4 degrees C, and solid state at 37 degrees C as well as its strong positive charge (pI 9), it may be used as a carrier of negatively charged proteins and nucleic acids. In addition, such complexes of atecollagen/therapeutics are easy to obtain and, depending upon the concentration of atelocollagen, they may be used to provide therapeutics to the organism locally or in a systemic manner. In this review the practical application of atelocollagen used as a carrier of proteins and nucleic acids (plasmids, antisense oligodeoxynucleotides, and siRNA) to treat inherited diseases and cancers is critically discussed. The observations described indicate that it is an optimal vehicle to transport medication which may be used in vivo with very limited risk. Therefore, atelocollagen has the potential to contribute significantly to the further development of gene therapy.