Cell-based therapy for epithelial wounds.

BACKGROUND AIMS: Bone marrow-derived cells (BMDC) form a significant portion of regenerating epithelial tissue. The purpose of this study was to determine whether exogenous BMDC (containing stroma, stem and progenitor cells), introduced systemically or within the injury site, could enhance the injury repair response. METHODS: Excisional wounds (10-mm diameter) were treated by systemic (intravenous; i.v.) and local (subcutaneous; s.c.) administration of BMDC (10-20 × 10(6)/100 µL phosphate-buffered saline). Young and aged BMDC and recipients were studied. RESULTS: Young BMDC (2 months old) increased the healing rate compared with older BMDC (1 year old), as measured by the rate of healing and the percentage of healed tissue. Young recipients had statistically better healing efficiency than older recipients. When old BMDC were used, young recipients had a better healing ability than older recipients. In addition, when the size of the healed tissue, the area of repigmentation and hair growth at the injury site were compared, young BMDC and young recipients had superior effects compared with old BMDC and old recipients. CONCLUSIONS: These results demonstrate that cellular therapy is important for wound healing in older recipients that do not heal significantly without intervention. BMDC injections result in normal healing, indistinguishable from young recipients. Significantly, a single injection into the wound margin is sufficient to reverse the wounding process and promote normal wound healing. Although younger recipients eventually healed without therapy, BMDC injections accelerated the process, reduced scarring and increased hair regrowth. These findings provide insight into the treatment of non-healing epithelial tissue with BMDC.

Characterization of arrangement and expression of the beta-2 microglobulin locus in the sandbar and nurse shark.

Beta 2 microglobulin (beta2m) is an essential subunit of major histocompatibility complex (MHC) type I molecules. In this report, beta2m cDNAs were identified and sequenced from sandbar shark spleen cDNA library. Sandbar shark beta2m gene encodes one amino acid less than most teleost beta2m genes, and 3 amino acids less than mammal beta2m genes. Although sandbar shark beta2m protein contains one beta sheet less than that of human in the predicted protein structure, the overall structure of beta2m proteins is conserved during evolution. Germline gene for the beta2m in sandbar and nurse shark is present as a single locus. It contains three exons and two introns. CpG sites are evenly distributed in the shark beta2m loci. Several DNA repeat elements were also identified in the shark beta2m loci. Sequence analysis suggests that the beta2m locus is not linked to the MHC I loci in the shark genome.