Distribution of the alpha-gal epitope on adult porcine bone tissue.
BACKGROUND
Bone xenografts from pig to human appear to be an alternative to resolve the shortage of bone autologous and allografts. However, the major obstacle of pig-to-human xenotransplantation is the interaction between human natural anti-Gal antibody and the alpha-Gal epitope abundantly expressed on pig endothelium. It was important to investigate the expression of alpha-Gal epitopes in porcine bone tissue to look for an ideal method to remove the alpha-Gal epitopes.


METHODS
The cortical and trabecular bone were retrieved from five pigs. After the soft tissues and periosteum were removed, the blood and marrow cavity were cleaned with phosphate-buffered solution. All 5 mm x 5 mm x 5 mm samples were imbedded in paraffin and methyl methacrylate resin for histological sections. The mouse IgM M86 monoclonal antibody, which was highly specific for alpha-Gal epitopes, was used to document alpha-Gal epitope expression by immunostaining of tissues and immunofluorescence.


RESULTS
Gal-positive immunostaining and immunofluorescence were observed on the surface of osteocytes and Haversian canals. There was a significant difference in Gal expression between cortical and trabecular bone tissues. There was no Gal expression in the extracellular matrix of bone.


CONCLUSIONS
Major alpha-Gal epitopes were on the surface of osteocytes of porcine bone tissues. A method should be used to damage the osteocytes and eliminate the alpha-Gal epitopes to avoid the xenogenic rejection in xenotransplantation of porcine bone tissues.
Feng
W
W
Orthopaedic Department, West China Hospital, Sichuan University, Guoxuexiang 37, Chengdu 610041, P.R. China.
Lian
Y
Y
Zhou
Z
Z
Lu
Y
Y
Li
S
S
Pei
F
F
Cheng
J
J
D000818:Animals; D016025:Bone Transplantation; D001842:Bone and Bones / Q000166:cytology / Q000502:physiology*; D000939:Epitopes / Q000032:analysis; D005697:Galactosides / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D013552:Swine; D014183:Transplantation, Heterologous
D000939:Epitopes; D005697:Galactosides