The osteogenic potential of human bone callus.

Bone callus, generated during fracture healing, is commonly discarded during surgical procedures. The aim of this study was to investigate the osteogenic potential of bone callus and its possible use as autograft material for patients needing bone grafts. Histology, immunohistochemistry, micro-computed tomography, and biomechanics were performed to examine osteogenic cells, osteoinductive factors, and the osteoconductive structure of bone callus. Alkaline phosphatase-positive osteoblasts, osteoinductive factors (including BMP2, FGF2, TGFB1, and IGF1), and a porous structure were found in bone callus. Early-stage callus (within 3 months after fracture) presented significantly improved osteogenic properties compared to medium- (3-9 months) and late-stage (longer than 9 months) callus. The results revealed that bone callus induced new bone formation in a nude mouse model. Early-stage callus showed better performance to medium- and late-stage callus in the induction of new bone formation at both 8 and 12 weeks. These findings indicated that bone callus, especially early-stage callus, possesses osteogenic potential and can potentially serve as an alternative source of material for bone grafts.

Effects of systemically transplanted allogeneic bone marrow multipotent mesenchymal stromal cells on rats' recovery after experimental polytrauma.

BACKGROUND: The aim of this study was to evaluate impact of transplantation of bone marrow mesenchymal stromal cells (BM MMSCs) on recovery after polytrauma and bone fracture repair. METHODS: A total 27 Wistar-Kyoto rats were divided into three groups (n = 9): normal control (A), polytrauma (B), and polytrauma treated with BM MMSC transplantation (C). The experimental polytrauma model was made on male rats by causing multiple fractures and hemorrhagic shock. At 36 hours 9 days after surgery, nine rats received allogeneic BM MMSCs (1 × 10(6) cells per kilogram) intravenously. The day before operation and at Days 3 and 10 after surgery as well as at the end of the experiment, blood analysis was carried out. At 10, 20, and 30 days after surgery the rats' locomotor activity was assessed in an open-field test. At Day 30, rats were euthanized, and macroscopic and histologic observations of rats' lower extremities was performed. RESULTS: The treated animals gained weight faster regained their physical activity earlier. These outcomes were associated with locomotor activity test results, blood glucose and lactate ratios, as well as less marked muscle atrophy.Rat treatment with BM MMSC transplantation stimulated bone fracture healing-bone edge consolidation and enhanced callus formation, as well as the size and maturity of newly formed trabeculae.Red blood cell analysis results showed delayed recovery after hemorrhage in the rats receiving allogeneic BM MMSCs: restoration of red blood cell counts, hematocrit level, and hemoglobin level was slower in the untreated animals. CONCLUSION: Allogeneic BM MMSC transplantation improved rats rehabilitation scores after experimental polytrauma.

Impacted bone and calcium phosphate cement for repair of femoral head defects: a pilot study.

Bone impaction grafting has been advocated for reconstruction of femoral head osteonecrosis. However, bone grafts do not prevent the progression of collapse and subsequent disabling osteoarthritis in late-stage osteonecrosis. We hypothesized reconstruction of large subchondral defects with a mix of impacted morsellized cancellous bone grafts and calcium phosphate cement would afford mechanical stability allowing remodeling into new bone without femoral head collapse. In a pilot study we created a critically sized subchondral defect model in 15 goats following the trapdoor procedure. Defects were left empty (n = 3), filled with morsellized cancellous bone grafts (n = 6), or filled with a mixture of morsellized cancellous bone and calcium phosphate cement (n = 6). No defects collapsed by sacrifice at 12 weeks. Defects filled with morsellized cancellous bone showed complete incorporation and remodeling to a normal trabecular structure. In the morsellized cancellous bone/calcium phosphate cement group, most of the calcium phosphate cement was resorbed in 12 weeks and the mixture was largely replaced by fibrous or fatty marrow. Although the specific mixture did not confirm our hypothesis, we suspect a slower resorbing calcium phosphate cement remains a promising material to mix with morsellized cancellous bone to treat late stages of femoral head osteonecrosis.

Compositional variation of fibrous callus and joint cartilage in different internal environments.

OBJECTIVE: To evaluate the compositional variation of fibrous callus in the fracture site and the joint cavity and joint cartilage after being transplanted in the muscle pouch. METHODS: Thirty 2 month old New Zealand white rabbits (weighing 1-1.5 kg) were randomly divided into two groups: a callus transplantation group (Group A, n=15) and a cartilage transplantation group (Group B, n=15). In Group A, closed radius fracture was made and the autologous fibrous callus was transplanted in the right knee joint cavity at 12 days postoperatively. In Group B, the right knee joint cartilage of the animals was transplanted in the autologous back muscle pouches under anesthesia. Then all the animals were killed by overdose anesthetic 3 weeks after transplantation. And the transplanted fibrous callus, the healed bones in the fracture sites and the transplanted joint cartilage were obtained for assessment of compositional variation. RESULTS: Pure fibrous composition was found in the callus at the fracture sites in Group A at 12 days postoperatively. And for 11 out of the 15 animals, the fibrous callus was transformed into cartilaginous tissues after 3 weeks of transplantation, but the fibrous callus was absent in the other 4 animals. The fibrous calluses at the original site and the fracture locus were differentiated into bony tissues. Bony tissue transformation was found in the transplanted joint cartilages in the muscle pouch of all the animals in Group B. CONCLUSIONS: The fracture sites or joint cavity may facilitate callus differentiation in different ways: the former is helpful for osteogenesis while the latter for the development and maintenance of cartilages, and the muscle pouch is inclined to induce the osteogenic phenotype for cartilages.

O uso do aspirado de medula óssea de ilíaco em falhas ósseas de fêmures de camundongos: estudo experimental / The use of inhaled bone marrow of ileum in bone failures of femurs of rats: experimental study

Os autores estudam a utilizacão de medula óssea em camundongos como estimulacão da formacão de calo ósseo. Foram utilizados dez camundongos adultos machos de linhagem isogênica gioto com peso de aproximadamente 250 gramas, e realizadas falhas ósseas na região distal do fêmur com alternância do lado direito e esquerdo, divididos em grupos A e B, sendo como controle camundongos com falha óssea isolado e com falhas ósseas com medula óssea colhida previamente de cada camundongo. Após análise qualitativa e quantitativa foi observado que o uso do aspirado de medula óssea não leva à estimulacão da formacão do calo ósseo e não há o aumento de processo inflamatório local.

[The preliminary result of osteoid callus allograft for bone healing].

OBJECTIVE: To investigate the feasibility of osteoid callus allograft as a kind of bone healing promoting materials. METHODS: The osteoid callus was obtained at one week after bilateral femoral fracture of a SD rat, then was kept at -196 C for 2 weeks. The bone defect model which bone repair was in intra-membranous osteogenesis was made at bilateral tibial shaft in 5 rats, and filled with the osteoid callus in the left defect area, the right side was filled with allogenous cancellous as control group. The specimen were processed with undecalcified technique and the sections were staining with light blue and sofranin T. RESULTS: After 2 weeks, there were cartilage and bone formation in the defect area of osteoid callus graft group(3/4), medullary cavity formation in bone tissue with cartilage arround it, fibrous tissues between new bone and host bone. While there were no cartilage or bone formation in the control group. CONCLUSION: The allograft osteoid callus is not absorbed by immunological rejection, but changed into bone tissue through endochondral osteogenesis. It is inspiring to develop osteoid callus allograft as a kind of material for bone healing.

Repair of osteochondral defects with autogenous callo-osseous grafts.

A new method of biological repair of osteochondral defects is presented. An osteochondral defect in the rabbit knee was reconstructed with an autogenous callo-osseous graft made of a superficial sheet of medullary fracture callus attached to a base of cancellous bone. The reparative tissues were evaluated for 24 weeks by histology, analysis of uronic acid contents, and immunohistochemical staining of collagen constituents. The callo-osseous graft provided significantly faster and better repair of the articular surface than an untreated defect or a callo-osseous graft in which the cells had been devitalized by irradiation prior to transplantation. The results indicate that the callo-osseous graft contributes to the repair process via providing both favorable extracellular matrices and pluripotential mesenchymal cells.

Regeneration of defects in articular cartilage with callus and cortical bone grafts. An experimental study.

Cartilage regeneration was studied in an experiment in rats. A standardised full-thickness articular cartilage defect was created and autogenous 12-day-old callus or cortical bone graft was transplanted into it, or the defect was left empty. The follow up periods were three, six, 12, and 24 weeks, and each subgroup consisted of five animals. A total of 60 animals were operated on. From six weeks onwards hyaline-like cartilaginous tissue had started to develop at the edges of the defect in all three groups. In the middle section of the hole, however, the picture was different; at 24 weeks none of the specimens in the defect group, two of the five in the callus graft group, and all five in the bone graft group had developed full-thickness, hyaline-like cartilaginous regeneration. The hyaline-like cartilaginous tissue in the medical segment was hypocellular when analysed by histomorphometry. On scanning electron microscopy the surface of the reparative tissue looked fibrillated in all specimens from the three groups.

Autogenous callo-osseous grafts for the repair of osteochondral defects.

We describe a new method of biological repair of osteochondral defects. In rabbit knees an osteochondral defect was reconstructed with a callo-osseous graft made of a superficial sheet of medullary fracture callus attached to a base of cancellous bone. This was taken from the iliac bone of the same animal which had been osteotomised ten days earlier. The reparative tissues were evaluated for 24 weeks by quantitative histology, biochemical analysis of the uronic acid content, and immunohistochemical staining of collagen constituents. The callo-osseous graft provided significantly faster and better repair of the articular surface than an untreated defect or a callo-osseous graft in which the cells had been devitalised by irradiation before transplantation. Our findings indicate that the callo-osseous graft contributes to the repair process by providing both favourable extracellular matrices and pluripotential mesenchymal cells. Our study tested the hypothesis that early medullary callus generates hyaline cartilage instead of bone after transfer to an articular surface.

Inflammation due to intra-cutaneous implantation of stratum corneum.

Fragments of sterile heel callus and suspensions of human corneocytes were implanted or injected intra-cutaneously into flank skin of guinea pigs. A mixed cellular type of inflammation was produced characterized by the accumulation of polymorphonuclear leucocytes in the early stages and a more granulomatous picture in the later stages. Epithelial hypertrophy and follicular distortion with transepidermal elimination was a frequent accompaniment. Immunoglobulins and the complement component C3 were found scattered irregularly in the inflammation produced and were not thought to be important in the process. The inflammation produced closely emulated the changes observed in acne inflammation and after rupture of horn containing cysts. It is suggested that inflammation caused by the implantation of horn may be suitable for study of human skin disease in which horny debris is released into the dermis, such as acne.