Http Dx Doi Org 10 3171 2009 1 Spine08565, Mar 20, 2009
New generations of devices for spinal interbody fusion are expected to arise from the combined us... more New generations of devices for spinal interbody fusion are expected to arise from the combined use of bioactive peptides and porous implants. The purpose of this dose-ranging study was to evaluate the fusion characteristics of porous ceramic granules (CGs) coated with the bioactive peptide B2A2-K-NS (B2A) by using a model of instrumented lumbar interbody spinal fusion in sheep. Instrumented spinal arthrodesis was performed in 40 operative sites in 20 adult sheep. In each animal, posterior instrumentation (pedicle screw and rod) and a polyetheretherketone cage were placed in 2 single-level procedures (L2-3 and L4-5). All cages were packed with graft material prior to implantation. The graft materials were prepared by mixing (1:1 vol/vol) CGs with or without a B2A coating and morselized autograft. Ceramic granules were coated with B2A at 50, 100, 300, and 600 microg/ml granules (50-B2A/CG, 100-B2A/CG, 300-B2A/CG, and 600-B2A/CG, respectively), resulting in 4 B2A-coated groups plus a control group (uncoated CGs). Graft material from each of these groups was implanted in 8 operative sites. Four months after arthrodesis, interbody fusion status was assessed with CT, and the interbody site was further evaluated with quantitative histomorphometry. All B2A/CG groups had higher CT-confirmed interbody fusion rates compared with those in controls (CGs only). Seven of 8 sites were fused in the 50-B2A/CG, 100-B2A/CG, and 300-B2A/CG groups, whereas 5 of 8 sites were fused in the group that had received uncoated CGs. New woven and lamellar bone spanned the fusion sites with excellent osseointegration. There was no heterotopic ossification or other untoward events attributed to the use of B2A/CG in any group. Each B2A/CG treatment produced more new bone than that in the CG group. Bioactive treatment with B2A effectively enhanced the fusion capacity of porous CGs. These findings suggest that B2A/CG may well represent a new generation of biomaterials for lumbar interbody fusion and indicate that additional studies are warranted.
The synthetic peptide B2A2-K-NS augmented the in vitro expression of osseous phenotypes when cell... more The synthetic peptide B2A2-K-NS augmented the in vitro expression of osseous phenotypes when cells were stimulated with BMP-2, an osteoinductive growth factor. B2A2-K-NS significantly enhanced the effects of BMP-2-induced alkaline phosphatase activity and mineralization. In the absence of BMP-2, B2A2-K-NS did not have an effect on these endpoints. Based on these observations, in vivo studies were conducted to evaluate if B2A2-K-NS could augment osseous phenotypes in an osteoinductive environment in which BMP-2 should be present. In one study, human demineralized bone matrix (DBM) was used to generate an osteoinductive environment and the effects of B2A2-K-NS on ectopic mineralization of subcutaneous implants evaluated. In the second study, a noncritical sized defect in rabbit ulnas with inherent reparative capacity was used as the osteoinductive environment and was treated with or without B2A2-K-NS. In the DBM studies, B2A2-K-NS augmented mineralization as determined using a combination of radiographic analysis and von Kossa staining at 4 weeks postimplant. In the rabbit ulna model, B2A2-K-NS significantly increased the radiographic bone density in the defects compared to carrier-only or no-treatment controls after 6 weeks. Histological staining confirmed that B2A2-K-NS generated a pronounced bone repair response. The results are consistent with the hypothesis that B2A2-K-NS augments osseous phenotypes in an osteoinductive environment, and suggests that B2A2-K-NS may have clinical utility.
New generations of devices for spinal interbody fusion are expected to arise from the combined us... more New generations of devices for spinal interbody fusion are expected to arise from the combined use of bioactive peptides and porous implants. The purpose of this dose-ranging study was to evaluate the fusion characteristics of porous ceramic granules (CGs) coated with the bioactive peptide B2A2-K-NS (B2A) by using a model of instrumented lumbar interbody spinal fusion in sheep. Instrumented spinal arthrodesis was performed in 40 operative sites in 20 adult sheep. In each animal, posterior instrumentation (pedicle screw and rod) and a polyetheretherketone cage were placed in 2 single-level procedures (L2-3 and L4-5). All cages were packed with graft material prior to implantation. The graft materials were prepared by mixing (1:1 vol/vol) CGs with or without a B2A coating and morselized autograft. Ceramic granules were coated with B2A at 50, 100, 300, and 600 microg/ml granules (50-B2A/CG, 100-B2A/CG, 300-B2A/CG, and 600-B2A/CG, respectively), resulting in 4 B2A-coated groups plus a control group (uncoated CGs). Graft material from each of these groups was implanted in 8 operative sites. Four months after arthrodesis, interbody fusion status was assessed with CT, and the interbody site was further evaluated with quantitative histomorphometry. All B2A/CG groups had higher CT-confirmed interbody fusion rates compared with those in controls (CGs only). Seven of 8 sites were fused in the 50-B2A/CG, 100-B2A/CG, and 300-B2A/CG groups, whereas 5 of 8 sites were fused in the group that had received uncoated CGs. New woven and lamellar bone spanned the fusion sites with excellent osseointegration. There was no heterotopic ossification or other untoward events attributed to the use of B2A/CG in any group. Each B2A/CG treatment produced more new bone than that in the CG group. Bioactive treatment with B2A effectively enhanced the fusion capacity of porous CGs. These findings suggest that B2A/CG may well represent a new generation of biomaterials for lumbar interbody fusion and indicate that additional studies are warranted.
The Journal of Bone and Joint Surgery (American), 2007
Clinical studies have demonstrated a high rate of incomplete healing of rotator cuff tendon repai... more Clinical studies have demonstrated a high rate of incomplete healing of rotator cuff tendon repair. Since healing of such a repair is dependent on bone ingrowth into the repaired tendon, we hypothesized that osteoinductive growth factors would improve rotator cuff tendon-healing. Seventy-two skeletally mature sheep underwent detachment of the infraspinatus tendon followed by immediate repair. The animals received one of three treatments at the tendon-bone interface: (1) an osteoinductive bone protein extract on a Type-I collagen sponge carrier, (2) the collagen sponge carrier alone, and (3) no implant. The animals were killed at six and twelve weeks, and the repaired rotator cuff was evaluated with use of magnetic resonance imaging, plain radiographs, histologic analysis, and biomechanical testing. A gap consistently formed between the end of the repaired tendon and bone in this model, with reparative scar tissue and new bone spanning the gap. Magnetic resonance imaging showed that the volume of newly formed bone (p < 0.05) and soft tissue (p < 0.05) in the tendon-bone gap were greater in the growth factor-treated animals compared with the collagen sponge control group at both time-points. Histologic analysis showed a fibrovascular tissue in the interface between tendon and bone, with a more robust fibrocartilage zone between the bone and the tendon in the growth factor-treated animals. The repairs that were treated with the osteoinductive growth factors had significantly greater failure loads at six weeks and twelve weeks (p < 0.05); however, when the data were normalized by tissue volume, there were no differences between the groups, suggesting that the treatment with growth factor results in the formation of poor-quality scar tissue rather than true tissue regeneration. The repairs that were treated with the collagen sponge carrier alone had significantly greater stiffness than the growth factor-treated group at twelve weeks (p = 0.005). This model tests the effects of growth factors on scar tissue formation in a gap between tendon and bone. The administration of osteoinductive growth factors resulted in greater formation of new bone, fibrocartilage, and soft tissue, with a concomitant increase in tendon attachment strength but less stiffness than repairs treated with the collagen sponge carrier alone.
We hypothesized that an exogenous bone growth factor could augment healing of a tendon graft in a... more We hypothesized that an exogenous bone growth factor could augment healing of a tendon graft in a bone tunnel in a rabbit anterior cruciate ligament-reconstruction model. Seventy rabbits underwent bilateral anterior cruciate ligament reconstructions with a semitendinosus tendon graft. ...
Introduction: Mesenchymal stem cells (MSCs) reside in many tissues including bone marrow, adipose... more Introduction: Mesenchymal stem cells (MSCs) reside in many tissues including bone marrow, adipose tissue, synovial fluid, dermis and muscle. MSCs can differentiate along a variety of cell lineages that can be used to regenerate bone and other tissues. Adipose derived MSCs share many of the characteristics of bone marrow derived stem cells (BMSCs), including extensive proliferative potential, but are much more abundant and easier to recover with a higher proliferation rate than BMSCs. Mesenchymal stem cells (MSCs) isolated from human cadaveric adipose tissue can be obtained in large quantities, and have been reported in the literature to be capable of inducing bone formation in vivo and ex vivo (1-3). The current experiment was designed to test the hypothesis that demineralized cancellous bone grafts (DCBG) provide an effective alternative substrate for selection and retention of stem cells derived from the SVF of adipose tissue. The objective of this study was to seed adipose derived stem cells onto DCBG and characterize these stem cell-seeded grafts for differentiation potential, cell phenotype, cell number, and donor variability, adherence to DCBG (histology and SEM) and BMP quantity with respect to the utility for bone repair.
Regenerative medicine requires an abundant source of human adult stem cells that can be readily a... more Regenerative medicine requires an abundant source of human adult stem cells that can be readily available. Mesenchymal stem cells (MSCs) isolated from adult human cadaveric adipose tissue can be obtained in large quantities, and have been reported in the literature to be capable of inducing bone formation. We have demonstrated that human cadaveric adipose derived MSC-seeded demineralized bone grafts have three important bone regeneration characteristics: a scaffold for stem cells to adhere, an osteoinduction signal (presence of BMP) and cellular osteogenesis potential (1). Studies have shown that in vivo bone regeneration can be obtained from undifferentiated adipose derived MSCs without prior in vitro BMP or chemical stimulation of osteogenesis (2). It is believed that microenvironment plays a critical role for stem cell differentiation. Although studies have demonstrated that MSC differentiate to the bone lineage under osteogenic conditions, these studies have not demonstrated the absence of differentiation to other mesenchymal lineages. The objective of this study was to determine if MSCs under osteogenic conditions would specifically differentiate to the osteogenic lineage without differentiation to the cartilage or fat lineages.
Mesenchymal stem cells (MSCs) isolated from cadaveric adipose tissue can be obtained in large qua... more Mesenchymal stem cells (MSCs) isolated from cadaveric adipose tissue can be obtained in large quantities, and have been reported in the literature to be capable of inducing bone formation in vivo and ex vivo.( 1-6 ) The hypothesis tested whether a demineralized cancellous bone matrix (DCBM) can provide an effective substrate for selection and retention of stem cells derived from the stromal vascular fraction (SVF) of adipose. Human cadaveric adipose tissue was recovered from a donor and digested. The resulting SVF-containing MSCs were seeded onto the demineralized bone allografts, after which the nonadherent cells were washed off. The MSCs were characterized using a flow cytometer and tri-lineage differentiation (osteogenesis, chondrogenesis, and adipogenesis) in vitro. The stem cell-seeded allografts were also characterized for cell number, adherence to the DCBM, osteogenic activity (alkaline phosphatase and Alizarin Red staining), and bone morphorgenic protein (BMP) quantity. Flow cytometry identified a mean total of 7.2% MSCs in SVF and 87.2% MSCs after culture. The stem cells showed the capability of differentiating into bone, cartilage, and fat. On the 21 stem cell-seeded bone allografts, there were consistent, attached, viable cells (100,744±22,762 cells/cube). An assessment of donor age, gender, and body mass index revealed no significant differences in cell numbers. Enzyme-linked immunosorbent assay revealed the presence of BMP-2 and BMP-7. In conclusion, this bone graft contains three key elements for bone regeneration: adhered osteogenic stem cells, 3D osteoconductive bone scaffold, and osteoinductive BMP signal. It therefore has the potential to be effective for bone regeneration.
Background: Peptide-enhanced (using the peptide 15 [P-15] synthetic peptide) anorganic bone matri... more Background: Peptide-enhanced (using the peptide 15 [P-15] synthetic peptide) anorganic bone matrix (ABM) particulate (PPart) grafts have demonstrated clinical and histologic success in human periodontal defects. Dispersion of ABM/P-15 in sodium hyaluronate carrier (PPutty) improves the handling properties of the graft material. The healing of ABM/P-15 particulate and ABM/P-15 putty was compared in critical-sized fenestration defects in 16 mongrel dogs.
This prospective study assessed vital bone quality and quantity after grafting maxillary sinuses ... more This prospective study assessed vital bone quality and quantity after grafting maxillary sinuses with anorganic bone mineral containing a cell binding peptide (ABM/P-15) in combination with DFDBA (Mix I), hydrogel/ABM/P-15 (Mix II), or PRP (Mix III). Fifteen maxillary sinuses in 12 patients were grafted with the ABM/P-15 mixtures and after 4 to 5 months, cores were taken and analyzed histologically and histomorphometrically. Fifty-nine screw-type implants were placed. Mixes containing a spacer material (Mix I and II) produced greater average vital bone, more mature bone, and more interconnected bone bridges from the cortical (oral) end to the most apical portion, compared to a mix that lacked a spacer material (Mix III). None of the 59 implants failed with any graft material up to 5 months following implant placement. The study demonstrates that new trabecular bone is formed after grafting ABM/P-15 in the sinus floor; that more vital bone is formed when ABM/P-15 is mixed with a spacer material than without; and that implants can be successfully placed.
Cell-extracellular cell matrix (ECM) interactions play a vital role in development including cyto... more Cell-extracellular cell matrix (ECM) interactions play a vital role in development including cytoskeletal structure, growth and differentiation. A 15 amino acid, non-RGD containing, peptide that is derived from type I collagen was tested for its ability to confer cell survival. Two routinely utilized bone graft materials, anorganic bone matrix (ABM) and ABM carrying the cell binding peptide P-15 were compared for cell viability and apoptosis. Anchorage-dependent human foreskin fibroblasts (HFF) or osteogenic MC3T3-E1 cells were seeded on ABM or ABM/P-15. After serum withdrawal, viability and level of apoptosis were significantly ðpo0:05Þ improved for cells on ABM/P-15 compared to cells on ABM. Scanning electron microscopy confirmed large, spread cells on ABM/P-15 and smaller cells with apoptotic cellular blebs on ABM. In addition, viable cell attachment was significantly greater on cells cultured on ABM/P-15 compared with demineralized freeze-dried bone allograft. This is the first report that the P-15 cell binding peptide, when complexed with ABM, promotes cell survival. The P-15 peptide may modulate cell number and tissue structure by the enhancement of viable cell attachment and via the regulation of apoptosis. r
Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements ... more Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements essential for bone healing. The purpose of this study was to assess the safety and effectiveness of CBA in foot and/or ankle arthrodeses. A prospective, multicenter, open-label clinical trial using CBA was performed. At 6 weeks and at 3, 6, and 12 months, imaging was performed and the subject's pain, function, and quality of life (QOL) status (Visual Analog Scale, American Orthopaedic Foot & Ankle Society Hindfoot Scale, and the Short Form 36) were recorded. The per protocol population consisted of 92 patients at 6 months and 76 patients at 12 months, with 153 and 129 total arthrodeses, respectively. At 6 months, fusion rates were 68.5% for all patients and 81.1% for all joints; at 12 months, rates were 71.1% and 86.8%, respectively. Certain high-risk subjects (eg, with diabetes or obesity) had fusion rates comparable to those of normal patients. Statistically significant improvement...
Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements ... more Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements essential for bone healing. The purpose of this study was to assess the safety and effectiveness of CBA in foot and/or ankle arthrodeses. A prospective, multicenter, open-label clinical trial using CBA was performed. At 6 weeks and at 3, 6, and 12 months, imaging was performed and the subject's pain, function, and quality of life (QOL) status (Visual Analog Scale, American Orthopaedic Foot & Ankle Society Hindfoot Scale, and the Short Form 36) were recorded. The per protocol population consisted of 92 patients at 6 months and 76 patients at 12 months, with 153 and 129 total arthrodeses, respectively. At 6 months, fusion rates were 68.5% for all patients and 81.1% for all joints; at 12 months, rates were 71.1% and 86.8%, respectively. Certain high-risk subjects (eg, with diabetes or obesity) had fusion rates comparable to those of normal patients. Statistically significant improvement...
Http Dx Doi Org 10 3171 2009 1 Spine08565, Mar 20, 2009
New generations of devices for spinal interbody fusion are expected to arise from the combined us... more New generations of devices for spinal interbody fusion are expected to arise from the combined use of bioactive peptides and porous implants. The purpose of this dose-ranging study was to evaluate the fusion characteristics of porous ceramic granules (CGs) coated with the bioactive peptide B2A2-K-NS (B2A) by using a model of instrumented lumbar interbody spinal fusion in sheep. Instrumented spinal arthrodesis was performed in 40 operative sites in 20 adult sheep. In each animal, posterior instrumentation (pedicle screw and rod) and a polyetheretherketone cage were placed in 2 single-level procedures (L2-3 and L4-5). All cages were packed with graft material prior to implantation. The graft materials were prepared by mixing (1:1 vol/vol) CGs with or without a B2A coating and morselized autograft. Ceramic granules were coated with B2A at 50, 100, 300, and 600 microg/ml granules (50-B2A/CG, 100-B2A/CG, 300-B2A/CG, and 600-B2A/CG, respectively), resulting in 4 B2A-coated groups plus a control group (uncoated CGs). Graft material from each of these groups was implanted in 8 operative sites. Four months after arthrodesis, interbody fusion status was assessed with CT, and the interbody site was further evaluated with quantitative histomorphometry. All B2A/CG groups had higher CT-confirmed interbody fusion rates compared with those in controls (CGs only). Seven of 8 sites were fused in the 50-B2A/CG, 100-B2A/CG, and 300-B2A/CG groups, whereas 5 of 8 sites were fused in the group that had received uncoated CGs. New woven and lamellar bone spanned the fusion sites with excellent osseointegration. There was no heterotopic ossification or other untoward events attributed to the use of B2A/CG in any group. Each B2A/CG treatment produced more new bone than that in the CG group. Bioactive treatment with B2A effectively enhanced the fusion capacity of porous CGs. These findings suggest that B2A/CG may well represent a new generation of biomaterials for lumbar interbody fusion and indicate that additional studies are warranted.
The synthetic peptide B2A2-K-NS augmented the in vitro expression of osseous phenotypes when cell... more The synthetic peptide B2A2-K-NS augmented the in vitro expression of osseous phenotypes when cells were stimulated with BMP-2, an osteoinductive growth factor. B2A2-K-NS significantly enhanced the effects of BMP-2-induced alkaline phosphatase activity and mineralization. In the absence of BMP-2, B2A2-K-NS did not have an effect on these endpoints. Based on these observations, in vivo studies were conducted to evaluate if B2A2-K-NS could augment osseous phenotypes in an osteoinductive environment in which BMP-2 should be present. In one study, human demineralized bone matrix (DBM) was used to generate an osteoinductive environment and the effects of B2A2-K-NS on ectopic mineralization of subcutaneous implants evaluated. In the second study, a noncritical sized defect in rabbit ulnas with inherent reparative capacity was used as the osteoinductive environment and was treated with or without B2A2-K-NS. In the DBM studies, B2A2-K-NS augmented mineralization as determined using a combination of radiographic analysis and von Kossa staining at 4 weeks postimplant. In the rabbit ulna model, B2A2-K-NS significantly increased the radiographic bone density in the defects compared to carrier-only or no-treatment controls after 6 weeks. Histological staining confirmed that B2A2-K-NS generated a pronounced bone repair response. The results are consistent with the hypothesis that B2A2-K-NS augments osseous phenotypes in an osteoinductive environment, and suggests that B2A2-K-NS may have clinical utility.
New generations of devices for spinal interbody fusion are expected to arise from the combined us... more New generations of devices for spinal interbody fusion are expected to arise from the combined use of bioactive peptides and porous implants. The purpose of this dose-ranging study was to evaluate the fusion characteristics of porous ceramic granules (CGs) coated with the bioactive peptide B2A2-K-NS (B2A) by using a model of instrumented lumbar interbody spinal fusion in sheep. Instrumented spinal arthrodesis was performed in 40 operative sites in 20 adult sheep. In each animal, posterior instrumentation (pedicle screw and rod) and a polyetheretherketone cage were placed in 2 single-level procedures (L2-3 and L4-5). All cages were packed with graft material prior to implantation. The graft materials were prepared by mixing (1:1 vol/vol) CGs with or without a B2A coating and morselized autograft. Ceramic granules were coated with B2A at 50, 100, 300, and 600 microg/ml granules (50-B2A/CG, 100-B2A/CG, 300-B2A/CG, and 600-B2A/CG, respectively), resulting in 4 B2A-coated groups plus a control group (uncoated CGs). Graft material from each of these groups was implanted in 8 operative sites. Four months after arthrodesis, interbody fusion status was assessed with CT, and the interbody site was further evaluated with quantitative histomorphometry. All B2A/CG groups had higher CT-confirmed interbody fusion rates compared with those in controls (CGs only). Seven of 8 sites were fused in the 50-B2A/CG, 100-B2A/CG, and 300-B2A/CG groups, whereas 5 of 8 sites were fused in the group that had received uncoated CGs. New woven and lamellar bone spanned the fusion sites with excellent osseointegration. There was no heterotopic ossification or other untoward events attributed to the use of B2A/CG in any group. Each B2A/CG treatment produced more new bone than that in the CG group. Bioactive treatment with B2A effectively enhanced the fusion capacity of porous CGs. These findings suggest that B2A/CG may well represent a new generation of biomaterials for lumbar interbody fusion and indicate that additional studies are warranted.
The Journal of Bone and Joint Surgery (American), 2007
Clinical studies have demonstrated a high rate of incomplete healing of rotator cuff tendon repai... more Clinical studies have demonstrated a high rate of incomplete healing of rotator cuff tendon repair. Since healing of such a repair is dependent on bone ingrowth into the repaired tendon, we hypothesized that osteoinductive growth factors would improve rotator cuff tendon-healing. Seventy-two skeletally mature sheep underwent detachment of the infraspinatus tendon followed by immediate repair. The animals received one of three treatments at the tendon-bone interface: (1) an osteoinductive bone protein extract on a Type-I collagen sponge carrier, (2) the collagen sponge carrier alone, and (3) no implant. The animals were killed at six and twelve weeks, and the repaired rotator cuff was evaluated with use of magnetic resonance imaging, plain radiographs, histologic analysis, and biomechanical testing. A gap consistently formed between the end of the repaired tendon and bone in this model, with reparative scar tissue and new bone spanning the gap. Magnetic resonance imaging showed that the volume of newly formed bone (p < 0.05) and soft tissue (p < 0.05) in the tendon-bone gap were greater in the growth factor-treated animals compared with the collagen sponge control group at both time-points. Histologic analysis showed a fibrovascular tissue in the interface between tendon and bone, with a more robust fibrocartilage zone between the bone and the tendon in the growth factor-treated animals. The repairs that were treated with the osteoinductive growth factors had significantly greater failure loads at six weeks and twelve weeks (p < 0.05); however, when the data were normalized by tissue volume, there were no differences between the groups, suggesting that the treatment with growth factor results in the formation of poor-quality scar tissue rather than true tissue regeneration. The repairs that were treated with the collagen sponge carrier alone had significantly greater stiffness than the growth factor-treated group at twelve weeks (p = 0.005). This model tests the effects of growth factors on scar tissue formation in a gap between tendon and bone. The administration of osteoinductive growth factors resulted in greater formation of new bone, fibrocartilage, and soft tissue, with a concomitant increase in tendon attachment strength but less stiffness than repairs treated with the collagen sponge carrier alone.
We hypothesized that an exogenous bone growth factor could augment healing of a tendon graft in a... more We hypothesized that an exogenous bone growth factor could augment healing of a tendon graft in a bone tunnel in a rabbit anterior cruciate ligament-reconstruction model. Seventy rabbits underwent bilateral anterior cruciate ligament reconstructions with a semitendinosus tendon graft. ...
Introduction: Mesenchymal stem cells (MSCs) reside in many tissues including bone marrow, adipose... more Introduction: Mesenchymal stem cells (MSCs) reside in many tissues including bone marrow, adipose tissue, synovial fluid, dermis and muscle. MSCs can differentiate along a variety of cell lineages that can be used to regenerate bone and other tissues. Adipose derived MSCs share many of the characteristics of bone marrow derived stem cells (BMSCs), including extensive proliferative potential, but are much more abundant and easier to recover with a higher proliferation rate than BMSCs. Mesenchymal stem cells (MSCs) isolated from human cadaveric adipose tissue can be obtained in large quantities, and have been reported in the literature to be capable of inducing bone formation in vivo and ex vivo (1-3). The current experiment was designed to test the hypothesis that demineralized cancellous bone grafts (DCBG) provide an effective alternative substrate for selection and retention of stem cells derived from the SVF of adipose tissue. The objective of this study was to seed adipose derived stem cells onto DCBG and characterize these stem cell-seeded grafts for differentiation potential, cell phenotype, cell number, and donor variability, adherence to DCBG (histology and SEM) and BMP quantity with respect to the utility for bone repair.
Regenerative medicine requires an abundant source of human adult stem cells that can be readily a... more Regenerative medicine requires an abundant source of human adult stem cells that can be readily available. Mesenchymal stem cells (MSCs) isolated from adult human cadaveric adipose tissue can be obtained in large quantities, and have been reported in the literature to be capable of inducing bone formation. We have demonstrated that human cadaveric adipose derived MSC-seeded demineralized bone grafts have three important bone regeneration characteristics: a scaffold for stem cells to adhere, an osteoinduction signal (presence of BMP) and cellular osteogenesis potential (1). Studies have shown that in vivo bone regeneration can be obtained from undifferentiated adipose derived MSCs without prior in vitro BMP or chemical stimulation of osteogenesis (2). It is believed that microenvironment plays a critical role for stem cell differentiation. Although studies have demonstrated that MSC differentiate to the bone lineage under osteogenic conditions, these studies have not demonstrated the absence of differentiation to other mesenchymal lineages. The objective of this study was to determine if MSCs under osteogenic conditions would specifically differentiate to the osteogenic lineage without differentiation to the cartilage or fat lineages.
Mesenchymal stem cells (MSCs) isolated from cadaveric adipose tissue can be obtained in large qua... more Mesenchymal stem cells (MSCs) isolated from cadaveric adipose tissue can be obtained in large quantities, and have been reported in the literature to be capable of inducing bone formation in vivo and ex vivo.( 1-6 ) The hypothesis tested whether a demineralized cancellous bone matrix (DCBM) can provide an effective substrate for selection and retention of stem cells derived from the stromal vascular fraction (SVF) of adipose. Human cadaveric adipose tissue was recovered from a donor and digested. The resulting SVF-containing MSCs were seeded onto the demineralized bone allografts, after which the nonadherent cells were washed off. The MSCs were characterized using a flow cytometer and tri-lineage differentiation (osteogenesis, chondrogenesis, and adipogenesis) in vitro. The stem cell-seeded allografts were also characterized for cell number, adherence to the DCBM, osteogenic activity (alkaline phosphatase and Alizarin Red staining), and bone morphorgenic protein (BMP) quantity. Flow cytometry identified a mean total of 7.2% MSCs in SVF and 87.2% MSCs after culture. The stem cells showed the capability of differentiating into bone, cartilage, and fat. On the 21 stem cell-seeded bone allografts, there were consistent, attached, viable cells (100,744±22,762 cells/cube). An assessment of donor age, gender, and body mass index revealed no significant differences in cell numbers. Enzyme-linked immunosorbent assay revealed the presence of BMP-2 and BMP-7. In conclusion, this bone graft contains three key elements for bone regeneration: adhered osteogenic stem cells, 3D osteoconductive bone scaffold, and osteoinductive BMP signal. It therefore has the potential to be effective for bone regeneration.
Background: Peptide-enhanced (using the peptide 15 [P-15] synthetic peptide) anorganic bone matri... more Background: Peptide-enhanced (using the peptide 15 [P-15] synthetic peptide) anorganic bone matrix (ABM) particulate (PPart) grafts have demonstrated clinical and histologic success in human periodontal defects. Dispersion of ABM/P-15 in sodium hyaluronate carrier (PPutty) improves the handling properties of the graft material. The healing of ABM/P-15 particulate and ABM/P-15 putty was compared in critical-sized fenestration defects in 16 mongrel dogs.
This prospective study assessed vital bone quality and quantity after grafting maxillary sinuses ... more This prospective study assessed vital bone quality and quantity after grafting maxillary sinuses with anorganic bone mineral containing a cell binding peptide (ABM/P-15) in combination with DFDBA (Mix I), hydrogel/ABM/P-15 (Mix II), or PRP (Mix III). Fifteen maxillary sinuses in 12 patients were grafted with the ABM/P-15 mixtures and after 4 to 5 months, cores were taken and analyzed histologically and histomorphometrically. Fifty-nine screw-type implants were placed. Mixes containing a spacer material (Mix I and II) produced greater average vital bone, more mature bone, and more interconnected bone bridges from the cortical (oral) end to the most apical portion, compared to a mix that lacked a spacer material (Mix III). None of the 59 implants failed with any graft material up to 5 months following implant placement. The study demonstrates that new trabecular bone is formed after grafting ABM/P-15 in the sinus floor; that more vital bone is formed when ABM/P-15 is mixed with a spacer material than without; and that implants can be successfully placed.
Cell-extracellular cell matrix (ECM) interactions play a vital role in development including cyto... more Cell-extracellular cell matrix (ECM) interactions play a vital role in development including cytoskeletal structure, growth and differentiation. A 15 amino acid, non-RGD containing, peptide that is derived from type I collagen was tested for its ability to confer cell survival. Two routinely utilized bone graft materials, anorganic bone matrix (ABM) and ABM carrying the cell binding peptide P-15 were compared for cell viability and apoptosis. Anchorage-dependent human foreskin fibroblasts (HFF) or osteogenic MC3T3-E1 cells were seeded on ABM or ABM/P-15. After serum withdrawal, viability and level of apoptosis were significantly ðpo0:05Þ improved for cells on ABM/P-15 compared to cells on ABM. Scanning electron microscopy confirmed large, spread cells on ABM/P-15 and smaller cells with apoptotic cellular blebs on ABM. In addition, viable cell attachment was significantly greater on cells cultured on ABM/P-15 compared with demineralized freeze-dried bone allograft. This is the first report that the P-15 cell binding peptide, when complexed with ABM, promotes cell survival. The P-15 peptide may modulate cell number and tissue structure by the enhancement of viable cell attachment and via the regulation of apoptosis. r
Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements ... more Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements essential for bone healing. The purpose of this study was to assess the safety and effectiveness of CBA in foot and/or ankle arthrodeses. A prospective, multicenter, open-label clinical trial using CBA was performed. At 6 weeks and at 3, 6, and 12 months, imaging was performed and the subject's pain, function, and quality of life (QOL) status (Visual Analog Scale, American Orthopaedic Foot & Ankle Society Hindfoot Scale, and the Short Form 36) were recorded. The per protocol population consisted of 92 patients at 6 months and 76 patients at 12 months, with 153 and 129 total arthrodeses, respectively. At 6 months, fusion rates were 68.5% for all patients and 81.1% for all joints; at 12 months, rates were 71.1% and 86.8%, respectively. Certain high-risk subjects (eg, with diabetes or obesity) had fusion rates comparable to those of normal patients. Statistically significant improvement...
Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements ... more Cellular bone allograft (CBA) possesses osteogenic, osteoinductive, and osteoconductive elements essential for bone healing. The purpose of this study was to assess the safety and effectiveness of CBA in foot and/or ankle arthrodeses. A prospective, multicenter, open-label clinical trial using CBA was performed. At 6 weeks and at 3, 6, and 12 months, imaging was performed and the subject's pain, function, and quality of life (QOL) status (Visual Analog Scale, American Orthopaedic Foot & Ankle Society Hindfoot Scale, and the Short Form 36) were recorded. The per protocol population consisted of 92 patients at 6 months and 76 patients at 12 months, with 153 and 129 total arthrodeses, respectively. At 6 months, fusion rates were 68.5% for all patients and 81.1% for all joints; at 12 months, rates were 71.1% and 86.8%, respectively. Certain high-risk subjects (eg, with diabetes or obesity) had fusion rates comparable to those of normal patients. Statistically significant improvement...
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