Bone marrow concentrate: a novel strategy for bone defect treatment.

BACKGROUND: Although strong efforts have been made over the last decade to introduce stem cell and tissue engineering treatment strategies to the field of orthopaedics, only few clinical applications are currently available. MATERIALS AND METHODS: The clinical outcomes of ten patients with volumetric bone deficiencies treated with mesenchymal stem cells and bone marrow aspirate are presented in this case series. Results were evaluated with radiographs. In addition to the in vivo data, we also presented in vitro data of BMC cultivated onto a porous collagen I scaffold and the technique of bone marrow aspiration via a commercially available system. RESULTS: Our results demonstrated that there is a rationale for a clinical application of BMC / bone aspirate in the treatment of osseous defects. The intraoperative harvest procedure is a safe method and does not significantly prolong the time of surgery. In addition, MSC isolated from the aspirate was able to adhere and proliferate onto a collagen scaffold in significant numbers after a 15 min incubation period. These cells were then able to allow osteogenic differentiation in vitro without any osteogenic stimuli. CONCLUSIONS: The local application of BMC / bone aspirate in the treatment of bone deficiencies may be a promising alternative to autogenous bone grafting and help reduce donor site morbidity.

Concentration of bone marrow total nucleated cells by a point-of-care device provides a high yield and preserves their functional activity.

Stem and progenitor cell therapy is a novel strategy to enhance cardiovascular regeneration. Cell isolation procedures are crucial for the functional activity of the administered cellular product. Therefore, new isolation techniques have to be evaluated in comparison to the Ficoll isolation procedure as the current gold standard. Here we prospectively evaluated a novel point-of-care device (Harvest BMAC System) for the concentration of bone marrow total nucleated cells (TNC) in comparison to the Ficoll isolation procedure for bone marrow mononucleated cells (MNC). The yield in total numbers of TNC was 2.4-fold higher for Harvest compared to Ficoll. Despite significant differences in their cellular compositions, the colony-forming capacity was similar for both products. Intriguingly, the migratory capacity was significantly higher for the Harvest TNC (164 +/- 66%; p = 0.007). In a mouse model of hind limb ischemia, the increase in blood flow recovery was similar between Harvest BM-TNC and Ficoll BM-MNC (0.53 +/- 0.20 vs. 0.46 +/- 0.15; p = 0.88). However, adjustment of the injected cell number based on the higher yield of Harvest TNC resulted in a significant better recovery (0.64 +/- 0.16 vs. 0.46 +/- 0.15; p = 0.003). Cells concentrated by the Harvest point-of-care device show similar or greater functional activity compared to Ficoll isolation. However, the greater yield of cells and the wider range of cell types for the Harvest device may translate into an even greater therapeutic effect.

Concentration of Bone Marrow Total Nucleated Cells by a Point-of-Care Device Provides a High Yield and Preserves Their Functional Activity.

Stem and progenitor cell therapy is a novel strategy to enhance cardiovascular regeneration. Cell isolation procedures are crucial for the functional activity of the administered cellular product. Therefore, new isolation techniques have to be evaluated in comparison to the Ficoll isolation procedure as the current gold standard. Here we prospectively evaluated a novel point-of-care device (Harvest BMAC System) for the concentration of bone marrow total nucleated cells (TNC) in comparison to the Ficoll isolation procedure for bone marrow mononucleated cells (MNC). The yield in total numbers of TNC was 2.4-fold higher for Harvest compared to Ficoll. Despite significant differences in their cellular compositions, the colony-forming capacity was similar for both products. Intriguingly, the migratory capacity was significantly higher for the Harvest TNC (164 ± 66%; p = 0.007). In a mouse model of hind limb ischemia, the increase in blood flow recovery was similar between Harvest BM-TNC and Ficoll BM-MNC (0.53 ± 0.20 vs. 0.46 ± 0.15; p = 0.88). However, adjustment of the injected cell number based on the higher yield of Harvest TNC resulted in a significant better recovery (0.64 ± 0.16 vs. 0.46 ± 0.15; p = 0.003). Cells concentrated by the Harvest point-of-care device show similar or greater functional activity compared to Ficoll isolation. However, the greater yield of cells and the wider range of cell types for the Harvest device may translate into an even greater therapeutic effect.

Use of a centrifugation-based, point-of-care device for production of canine autologous bone marrow and platelet concentrates.

OBJECTIVE: To analyze a centrifugation-based, point-of-care device that concentrates canine platelets and bone marrow-derived cells. ANIMALS: 19 adult sexually intact dogs. PROCEDURES: Anticoagulated peripheral blood (60 mL) and 60 mL of anticoagulated bone marrow aspirate (BMA) were concentrated by centrifugation with the centrifugation-based, point-of-care device to form a platelet and a bone marrow concentrate (BMC) from 11 dogs. Blood samples were analyzed on the basis of hemograms, platelet count, and PCV. The BMA and BMC were analyzed to determine PCV, total nucleated cell count, RBC count, and differential cell counts. The BMC stromal cells were cultured in an osteoinductive medium. Eight additional dogs were used to compare the BMC yield with that in which heparin was infused into the bone marrow before aspiration. RESULTS: The centrifugation-based, point-of-care device concentrated platelets by 6-fold over baseline (median recovery, 63.1%) with a median of 1,336 x 10(3) platelets/microL in the 7-mL concentrate. The nucleated cells in BMCs increased 7-fold (median recovery, 42.9%) with a median of 720 x 10(3) cells/microL in the 4-mL concentrate. The myeloid nucleated cells and mononuclear cells increased significantly in BMCs with a significant decrease in PCV, compared with that of BMAs. Stromal cell cultures expressed an osteoblastic phenotype in culture. Infusion of heparin into the bone marrow eliminated clot formation and created less variation in the yield (median recovery, 61.9%). CONCLUSIONS AND CLINICAL RELEVANCE: Bone marrow-derived cell and platelet-rich concentrates may form bone if delivered in an engineered graft, thus decreasing the need for cancellous bone grafts.

Modulation of wound response and soft tissue ingrowth in synthetic and allogeneic implants with platelet concentrate.

OBJECTIVE: To evaluate the modulation of wound healing and soft tissue ingrowth in synthetic and allogeneic implants with platelet gel. Attempts to influence wound healing with exogenous growth factors are highly dependent on the timing and dosing of treatment. Platelet gel made from autologous platelet concentrate (PC) and activated with calcium thrombin is increasingly used to enhance healing of surgical and chronic wounds, based on the assumption that proteins found in the blood can promote healing. METHODS: Adult New Zealand white rabbits underwent phlebotomy, and the blood was used to produce nonconcentrated autologous blood clot, platelet-poor plasma (PPP), and PC for each animal. Disks of porous high-density polyethylene (PHDPE) and acellular dermal graft (ADG) were implanted into each animal in a subcutaneous location. Implants of each type were treated with isotonic sodium chloride solution, PPP, PPP followed immediately with PC, or autologous blood clot (by means of manual impregnation). Animals were killed at 2, 7, 14, and 21 days after implantation. Implants were harvested with surrounding soft tissue and examined by means of light microscopy for evidence of acute and chronic inflammatory cells and vascular and fibroblast invasion. RESULTS: A platelet gel with platelet concentrations averaging 5.8 times greater than those of peripheral blood significantly improved wound healing and soft tissue ingrowth in surgically implanted grafts. Early inflammatory infiltrates were enhanced in PHDPE and ADG implants by PC and autologous blood clot compared with control implants, as evidenced by significantly increased neutrophil and macrophage counts at day 2. Compared with controls, statistically significant increases in fibroblast and endothelial cell counts were noted at day 7 in PC-treated implants (fibroblasts, 61% increase [P < .001] in PHDPE implants and 52% increase [P < .001] in ADG implants; capillaries, 95% increase [P < .05] in PHDPE and 97% increase [P < .001] in ADG implants). Lymphocyte counts were increased by PC in PHDPE and ADG implants (71% [P < .001] and 100% [P < .05], respectively). There were no statistically significant differences in any cell count variables beyond 7 days. CONCLUSIONS: Treatment with PC prepared at 5 times the baseline platelet count significantly accelerated maturation of experimental wounds. By 14 days, the degree and quality of wound cellularity were equivalent among all treatment groups. Rapid wound healing was expected with this surgical model, which was chosen to observe the biological effects on early wound healing of a platelet gel in a noncompromised wound. Treatment with PC may be useful in scenarios in which enhancement and acceleration of early wound healing is desired.

Comparison of methods for point of care preparation of autologous platelet gel.

A platelet gel (PG) is produced by the addition of calcium chloride and thrombin to a platelet concentrate (PC). PG releases multiple growth factors, which have the ability to initiate and stimulate one growth factor's function in the presence of others. This finding has resulted in the use of PG in orthopedic, plastic, and reconstructive surgery. The study compared the commercial systems available for the preparation of PG. All procedures were performed according to the manufacturers directions. The devices were evaluated with respect to ease of use, collection efficiency, platelet quality, and growth factor release. The SmartPReP requires only four processing steps compared to 12 to 24 required by other devices. The SmartPReP and the CATS were the most reproducible, as evidenced by their low coefficient of variation of 13% and 16%. The mean platelet yield was 72% for the SmartPReP, 58% for the 3iPCCS, 54% for the Sequestra, 31% for the Secquire, 31% for the CATS, 27% for the Interpore Cross, and 42.6% for the Biomet GPS. The mean total amount of PDGF-AB and TGF-B1 obtained from the SmartPReP is greater than other systems evaluated. The SmartPReP produced a consistent PC with a yield that was four times baseline range with the lowest coefficient of variation.

An in vitro and in vivo evaluation of autologous platelet concentrate in oral reconstruction.

A platelet concentrate, when combined with calcified thrombin, produces a platelet gel that has been used to achieve hemostasis and modulate bone growth and wound healing. The recovery of high concentrations of viable platelets and their resulting growth factor levels represents the most important factor in the clinical utility of a platelet concentrate because only functional platelets can release the growth factors that are necessary to induce tissue growth and bone regeneration. The SmartPReP system's efficiency in recovery of platelets from a sample of whole blood averaged 70.6%, almost twice that of various manual techniques using laboratory centrifuges. Platelet concentrates prepared by the SmartPReP system had a viability equal to platelet concentrates prepared for transfusion as measured by hypotonic stress, platelet aggregation, and p-selectin. A series of clinical case studies demonstrates the use of autologous platelet gel in oral surgery.