Generation of donor hematolymphoid cells after rat-limb composite grafting.
BACKGROUND
Composite tissue allografts are unique because they provide the vascularized bone marrow with stroma, which is the supportive microenvironment. In this study, we investigated the beneficial effect of donor-derived bone marrow cells within the long-surviving recipient rats after limb transplantation.


METHODS
Green fluorescent protein (GFP) transgenic rats developed for paramount cell marking were donors, and wild Wistar rats were recipients. Orthotopic hind-limb transplantation was performed using a microsurgical technique. Tacrolimus (1.0 mg/kg) was intramuscularly injected for 14 days postoperatively. The skin graft from GFP donor onto the GFP recipient was performed as a control. Flow cytometric analyses of recipient peripheral blood and bone marrow were carried out at 4 to 6 days, 18 to 21 days, 6 weeks, and 2, 4, 6, 9, and 12 months after transplantation.


RESULTS
The rats that received tacrolimus therapy achieved prolonged composite graft acceptance more than 12 months, whereas GFP skin grafts were rejected at 47 days under the same immunosuppressive protocol. Numerous GFP lymphocytes and granulocytes were detected within the recipient bone marrow for the first 6 weeks post limb transplantation. These cells remained relatively stable for more than 12 months.


CONCLUSIONS
The results showed that donor-derived hematopoietic stem cells engrafted in recipient bone marrow and differentiated to lymphocytes and granulocytes after limb transplantation. The vascularized bone marrow, transplanted as a part of the hind limb, could have contributed to mixed chimerism and worked as the bone-marrow source in the recipients.
Ajiki
Takashi
T
Center for Molecular Medicine, Jichi Medical School, Tochigi, Japan.
Takahashi
Masafumi
M
Inoue
Seiichiro
S
Sakuma
Yasunaru
Y
Oyama
Shigetaka
S
Kaneko
Takashi
T
Hakamata
Yoji
Y
Murakami
Takashi
T
Kume
Akihiro
A
Kariya
Yusei
Y
Hoshino
Yuichi
Y
Kobayashi
Eiji
E
D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics; D001853:Bone Marrow / Q000473:pathology; D016026:Bone Marrow Transplantation; D002678:Chimera; D015870:Gene Expression; D006085:Graft Survival / Q000187:drug effects; D006098:Granulocytes / Q000473:pathology; D049452:Green Fluorescent Proteins; D018380:Hematopoietic Stem Cell Transplantation; D006614:Hindlimb / Q000637:transplantation*; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007202:Indicators and Reagents; D008164:Luminescent Proteins / Q000235:genetics; D008214:Lymphocytes / Q000473:pathology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D016038:Skin Transplantation; D016559:Tacrolimus / Q000627:therapeutic use; D014019:Tissue Donors
D007166:Immunosuppressive Agents; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins; D016559:Tacrolimus