Clinical applications of concentrated growth factors combined with bone substitutes for alveolar ridge preservation in maxillary molar area: a randomized controlled trial

Purpose To evaluate the clinical effects of concentrated growth factors (CGFs) combined with bone substitutes for alveolar ridge preservation (ARP) in the maxillary molar area. Methods Thirty-six patients who underwent extraction of the upper molars were recruited and randomly divided into three groups: 1. Grafted with CGFs combined with deproteinized bovine bone mineral (DBBM) and covered with CGFs membrane (CGFs/DBBM group), 2. Grafted with DBBM alone and covered with collagen membrane (DBBM group), 3. Control group spontaneous healing. The area of the alveolar bone in center (C-), mesial (M-) and distal (D-) section was compared with preoperative in radiography. Bone cores were obtained for histopathology observation and comparison. Results In C-, M- and D-section, the alveolar ridge area in all three groups was significantly reduced at 8 months postoperatively compared to the baseline (P < 0.05). The alveolar ridge area declines in the CGFs/DBBM group (C-12.75 ± 2.22 mm2, M-14.69 ± 2.82 mm2, D-16.95 ± 4.17 mm2) and DBBM group (C-14.08 ± 2.51 mm2, M-15.42 ± 3.47 mm2, D-16.09 ± 3.97 mm2) were non-significant differences. They were significantly less than the decline in the control group (C-45.04 ± 8.38 mm2 M-31.98 ± 8.34 mm2, D-31.85 ± 8.52 mm2) (P < 0.05). The percentage of newly formed bone in the CGFs/DBBM group (41.99 ± 12.99%) was significantly greater than that in DBBM group (30.68 ± 10.95%) (P < 0.05). The percentage of residual materials in the CGFs/DBBM group (16.19 ± 6.63%) was significantly less than that in the DBBM group (28.35 ± 11.70%) (P < 0.05). Conclusion Combined application of CGFs and DBBM effectively reduced the resorption of alveolar ridge and resulted in more newly formed bone than the use of DBBM with collagen membranes.

Concentrated Growth Factors in Combination with Particulate Bio-Oss Graft: A Pilot Study on Beagle Dog Alveolar Bone Deficient

Background: Alveolar bone related defect has emerged as a major challenge for clinician. Previous studies reported that concentrated growth factors (CGF), an autogenous product derived from venous blood, could enhance healing of grafts via releasing various growth factors. Methods: This study was designed to investigate the osteogenesis of CGF gel accompanied with Bio-Oss in canine alveolar defect socket model. CGF gel were prepared via variable speed centrifugation. Immunohistochemical staining and semi-quantitative analysis were performed to evaluate the content of transforming growth factor-β1 (TGF-β1) and vascular endothelial growth factor (VEGF) in the CGF gel and red blood cell (RBC) layer. The decay rate of TGF-β1 and VEGF were determined by ELISA assay. Next, mixture of Bio-Oss and CGF gel was implanted as graft to the alveolar defect socket. Three different fluorescent dyes and toluidine blue staining were utilized to track osteogenic progress, and mineral apposition rate (MAR) was calculated. Results: In the CGF gel, TGF-β1 occupied the dominant content with a higher decay rate than that of VEGF. Whereas, the concentration of TGF-β1 released from CGF gel still raised up rapidly within 14 days. In the animal study, combination of Bio-Oss and CGF gel not only accelerated wound healing, but also succussed to activate and sustain the bone formation at defect site represented as a higher MAR (2.21 ± 0.52 µm/day vs 1.43 ± 0.41 µm/day, Bio-Oss group and 1.04 ± 0.26 µm/day, control groups, P < 0.05). Conclusions: combination of Bio-Oss and CGF gel could promote osteogenesis and might provide a promising strategy against alveolar bone defect.

Application of Concentrated Growth Factors Membrane for Human Umbilical Cord Wharton’s Jelly Mesenchymal Stem Cell Differentiation towards Keratinocytes

Concentrated growth factors are extracted from platelet-rich plasma obtained from healthy adult veins by physical gradient centrifugation, and the activated platelets release various growth factors and cytokines, which can be further converted into concentrated growth factors liquid or gel preparations by different centrifuge tubes. These preparations are widely used in clinical treatments in various fields, such as dentistry, dermatology and surgery. In this article, concentrated growth factors gel and platelet-poor plasma gel obtained from six healthy adults were pressed into a concentrated growth factors membrane and platelet-poor plasma membrane. We examined whether the 3D fibrin mesh and the various concentrated growth factors within the concentrated growth factors membrane could be used as a bioscaffold for the human Wharton’s jelly umbilical cord stem cell line or the HaCaT cell line to attach, proliferate and form epidermal-like tissue. We also aimed to implant umbilical cord stem cells on the concentrated growth factors membrane or platelet-poor plasma membrane, and further compare the characteristics of similar tissues after 4 weeks in in vitro culture. The results showed that human Wharton’s jelly umbilical cord mesenchymal stem cells, implanted on the upper surface of the concentrated growth factors membrane, showed subsequent cell attachment and proliferation. After 4 weeks of ex vivo tissue culture, a multi-layer epidermal-like tissue formed on the upper surface of the membrane containing concentrated growth factors. This tissue had a minimum thickness of 89.91 µm to a maximum of 204.19 µm, mean ± SD = 144.36 µm ± 43.14 µm. Sections of these multi-layer epidermal-like tissues were used for immunohistochemical staining. We found that 79.8% ± 7.2% of the cells expressed the pancytokeratin marker, 29.5% ± 9.4% of the cells expressed the P63 marker, and 71.7% ± 3.9% of the cells expressed the vimentin marker. After the same 4 weeks in the in vitro culture, the HaCaT cells could attach to the concentrated growth factors membrane and proliferate to form a multi-layer tissue, The tissue had a minimum thickness of 63.17 µm to a maximum of 100.26 µm, mean ± SD = 74.05 µm ± 13.44 µm. We found that 88.1% ± 4.9% of the cells expressed the pancytokeratin marker, 63.6% ± 11.4% of the cells expressed the P63 marker, and 79% ± 9.9% of the cells expressed the vimentin marker. Also, after 4 weeks in the in vitro culture, it showed that umbilical cord stem cells could attach to the platelet-poor plasma membrane, proliferate and distribute in the whole-tissue sections. We found that 9.7% ± 2.4% of the cells expressed the pancytokeratin marker, 7.45% ± 1.9% of the cells expressed the P63 maker, and 95.9% ± 3.7% of the cells expressed the vimentin marker. In terms of the percentage of umbilical cord stem cells expressing pancytokeratin, P63, or vimentin cell markers, there was a significant difference between cultivating in the concentrated growth factors membrane scaffold and the platelet-poor plasma membrane scaffolds. In terms of the percentage of umbilical cord stem cells or HaCaT cells (cultivating in the concentrated growth factors membrane) expressing pancytokeratin, P63, or vimentin cell markers, there was no significant difference. These results suggested that umbilical cord Wharton’s jelly mesenchymal stem cells can use the concentrated growth factors membrane (composed of 3D fibrin mesh, and various growth factors and cytokines) as an effective and self-contained bioscaffold to differentiate towards keratinocytes-like cells. In the future, donors’ own concentrated growth factors membrane can be applied as an auxiliary tool for autologous tissue regeneration.

Angiogenic Properties of Concentrated Growth Factors (CGFs): The Role of Soluble Factors and Cellular Components

Blood-derived concentrated growth factors (CGFs) represent a novel autologous biomaterial with promising applications in regenerative medicine. Angiogenesis is a key factor in tissue regeneration, but the role played by CGFs in vessel formation is not clear. The purpose of this study was to characterize the angiogenic properties of CGFs by evaluating the effects of its soluble factors and cellular components on the neovascularization in an in vitro model of angiogenesis. CGF clots were cultured for 14 days in cell culture medium; after that, CGF-conditioned medium (CGF-CM) was collected, and soluble factors and cellular components were separated and characterized. CGF-soluble factors, such as growth factors (VEGF and TGF-β1) and matrix metalloproteinases (MMP-2 and -9), were assessed by ELISA. Angiogenic properties of CGF-soluble factors were analyzed by stimulating human cultured endothelial cells with increasing concentrations (1%, 5%, 10%, or 20%) of CGF-CM, and their effect on cell migration and tubule-like formation was assessed by wound healing and Matrigel assay, respectively. The expression of endothelial angiogenic mediators was determined using qRT-PCR and ELISA assays. CGF-derived cells were characterized by immunostaining, qRT-PCR and Matrigel assay. We found that CGF-CM, consisting of essential pro-angiogenic factors, such as VEGF, TGF-β1, MMP-9, and MMP-2, promoted endothelial cell migration; tubule structure formation; and endothelial expression of multiple angiogenic mediators, including growth factors, chemokines, and metalloproteinases. Moreover, we discovered that CGF-derived cells exhibited features such as endothelial progenitor cells, since they expressed the CD34 stem cell marker and endothelial markers and participated in the neo-angiogenic process. In conclusion, our results suggest that CGFs are able to promote endothelial angiogenesis through their soluble and cellular components and that CGFs can be used as a biomaterial for therapeutic vasculogenesis in the field of tissue regeneration.

Graphene-Modified Titanium Surface Enhances Local Growth Factor Adsorption and Promotes Osteogenic Differentiation of Bone Marrow Stromal Cells

Graphene coating exhibits excellent abilities of protein adsorption and cell adhesion, which might expand the osteogenic activity of titanium implant surface to adapt to the environment of low bone mass and poor bone quality. In this paper, we designed and explored the graphene-coated titanium sheet, through the surface modification of oxygen-containing functional groups, to optimize the adsorption capacity of material by improving the electrostatic interactions, and successfully adsorbed and sustained-released a variety of osteogenic related growth factors in the autologous concentrated growth factors. Compared with the pure titanium, we observed that the bone marrow stromal cells (BMSCs) on the graphene-coated titanium with concentrated growth factors showed a flat shape and expressed osteogenic related genes and proteins, while the coating surfaces promoted and accelerated the osteogenic differentiation ability of BMSCs. The results suggested that it might be a feasible alternative to improve the osteogenesis of dental implant in the early stage.

Application of a New Type of Natural Calcined Bone Repair Material Combined with Concentrated Growth Factors in Bone Regeneration in Rabbit Critical-Sized Calvarial Defect

Purpose. This study is aimed at investigating bone regeneration in critical-sized defects in rabbit calvarium using a novel nano- (n-) hydroxyapatite hybrid scaffold with concentrated growth factors (CGFs). Methods. Twenty-four male adult rabbits were chosen to establish a critical-sized bone defect model and randomly divided into two groups. Two defects of 15 mm diameter each were created in the parietal bone of each animal. Group A had n-hydroxyapatite hybrid scaffold placed in the experimental defect on the right, and the left defect was unfilled as blank. Group B had hydroxyapatite hybrid scaffold mixed with CGF placed in the right defect and CGF on the left. Six animals in each group were sacrificed after 6 and 12 weeks. Cone-beam computed tomography system scanning and hematoxylin and eosin (HE) staining were used to detect osteogenesis within the defects. Results. The treatment with n-hydroxyapatite hybrid scaffold along with CGF resulted in a significantly higher amount of new bone at 6 and 12 weeks compared to the treatment with CGF alone and the controls. No apparent inflammation and foreign body reaction were observed through HE staining. Conclusions. The new synthesized n-hydroxyapatite hybrid scaffold and CGF can be applied for bone defect regeneration to promote the process to a certain extent.