Combination Of Platelet-derived Growth factor-BB Research Articles

Combination of PDGF-BB and adipose-derived stem cells accelerated wound healing through modulating PTEN/AKT pathway

Adipose-derived stem cells (ADSCs) have been widely proven to facilitate wound healing. Our study aimed to estimate the influence of combined ADSCs and platelet-derived growth factor-BB (PDGF-BB) on wound healing. We utilized 4 healthy SD rats to isolate ADSCs. Platelet-rich plasma (PRP) was acquired utilizing a two-step centrifugation technology. The role of PRP, PDGF-BB, and PDGF-BB combined with a PI3k inhibitor LY294002 on the viability, migration, and PTEN/AKT pathway in ADSCs were examined utilizing CCK-8, Transwell, and western blot assays. Then, we constructed an open trauma model in SD rats. Effects of ADSCs treated with PDGF-BB on pathological changes, CD31, and PTEN/AKT pathway of wound closure were assessed by hematoxylin & eosin (H&E) staining, Masson staining, immunohistochemical, and western blot assays, respectively. PRP and PDGF-BB intensified the viability and migration of ADSCs by modulating the PTEN/AKT pathway. Interestingly, LY294002 reversed the role of PDGF-BB on ADSCs. In vivo experiments, combined intervention with ADSCs plus PDGF-BB/PRP facilitated wound closure and ameliorated histological injury. Moreover, combined intervention with ADSCs and PDGF-BB attenuated the PTEN level and elevated the CD31 level as well as the ratio of p-AKT/AKT in the skin tissues. A combination of ADSCs and PDGF-BB facilitated wound healing might associate with the regulation of the PTEN/AKT pathway.

Growth Factor-Mediated Migration of Bone Marrow Progenitor Cells for Accelerated Scaffold Recruitment.

Tissue engineering approaches using growth factor-functionalized acellular scaffolds to support and guide repair driven by endogenous cells are thought to require a careful balance between cell recruitment and growth factor release kinetics. The objective of this study was to identify a growth factor combination that accelerates progenitor cell migration into self-assembling peptide hydrogels in the context of cartilage defect repair. A novel 3D gel-to-gel migration assay enabled quantification of the chemotactic impact of platelet-derived growth factor-BB (PDGF-BB), heparin-binding insulin-like growth factor-1 (HB-IGF-1), and transforming growth factor-β1 (TGF-β1) on progenitor cells derived from subchondral bovine trabecular bone (bone-marrow progenitor cells, BM-PCs) encapsulated in the peptide hydrogel [KLDL]3. Only the combination of PDGF-BB and TGF-β1 stimulated significant migration of BM-PCs over a 4-day period, measured by confocal microscopy. Both PDGF-BB and TGF-β1 were slowly released from the gel, as measured using their (125)I-labeled forms, and they remained significantly present in the gel at 4 days. In the context of augmenting microfracture surgery for cartilage repair, our strategy of delivering chemotactic and proanabolic growth factors in KLD may provide the necessary local stimulus to help increase defect cellularity, providing more cells to generate repair tissue.

Enhancement of Angiogenesis Through Stabilization of Hypoxia-inducible Factor-1 by Silencing Prolyl Hydroxylase Domain-2 Gene

Hypoxia-inducible factor-1 (HIF-1) plays a central role in cellular response to hypoxia by activating vascular endothelial growth factor (VEGF) and other angiogenic factors. Prolyl hydroxylase domain-2 (PHD2) protein induces the degradation of HIF-1 by hydroxylating specific prolyl residues. Therefore gene silencing of PHD2 by RNA interference (RNAi) might increase the expression of angiogenic growth factors and, consequently, neoangiogenesis through the stabilization of HIF-1alpha. In this study we have shown that the specific silencing of PHD2 is sufficient for stabilizing HIF-1alpha and increasing its transcriptional activity, resulting in the increased expression of angiogenic factors including VEGF and fibroblast growth factor-2 (FGF2). Moreover, when PHD2-siRNA vector was used, the increase in VEGF secretion was observed for as long as 18 days after transfection. In vitro treatment of human umbilical vein endothelical cells with conditioned medium from PHD2-siRNA vector-transfected NIH3T3 cells was shown to increase cell proliferation. Also, in vivo angiogenesis was observed in mice implanted with Matrigel plugs mixed with NIH3T3 cells transfected with PHD2-siRNA vector. These results indicate that PHD2 silencing induces expressions of multiple angiogenic growth factors by stabilizing HIF-1alpha, and that the implantation of cells transfected with PHD2-siRNA vector is sufficient to enhance angiogenesis in vivo. In the light of these findings, PHD2 silencing by RNAi might offer a potential tool for angiogenic therapy.

Effect of Several Growth Factors on Canine Flexor Tendon Fibroblast Proliferation and Collagen Synthesis In Vitro

Growth factor delivery may be useful to accelerate the rate of tendon healing. Before in vivo use, however, the effects of growth factors on tendon cells need to be well characterized. The purpose of this study was to evaluate the effects of 4 growth factors on intrasynovial tendon fibroblast proliferation and collagen production in vitro. Our first hypothesis was that platelet-derived growth factor BB (PDGF-BB) and basic fibroblast growth factor (bFGF) would promote cell proliferation and collagen production. Our second hypothesis was that there would be a positive effect from the combination of PDGF-BB and bFGF. The growth factors PDGF-BB, bFGF, vascular endothelial growth factor (VEGF), and bone morphogenetic protein 2 (BMP-2) were evaluated in vitro with canine flexor tendon fibroblasts. The effects of single factors (PDGF-BB, bFGF, VEGF, or BMP-2) or a combination of factors (PDGF-BB and bFGF) on cell proliferation (ie, thymidine incorporation) and collagen production (ie, proline incorporation) were evaluated. The results supported our hypotheses. Cell proliferation increased significantly with PDGF-BB and bFGF. Collagen production also increased significantly with PDGF-BB and bFGF. Cell proliferation and collagen production were unchanged with VEGF and BMP-2. A dose-response effect was seen for PDGF-BB combined with bFGF. The combination of PDGF-BB and bFGF led to an increase in cell proliferation but no change in collagen production compared with each factor alone. The growth factors PDGF-BB and bFGF significantly increased flexor tendon fibroblast proliferation and matrix synthesis when applied singly. Administration of PDGF-BB and bFGF combined led to increased proliferation to single factors.

Effect on the Healing of Periapical Perforations in Dogs of the Addition of Growth Factors to Calcium Hydroxide

The purpose of this study was to investigate the effect of the addition of platelet-derived growth factor-BB and insulin-like growth factor-I to calcium hydroxide in the repair of apical perforations in dogs. Fifty-one premolar teeth of four beagle dogs were used. After developing periapical lesions root apices were artificially perforated. The teeth were divided into the three groups: group 1, the apical perforations were not sealed; group 2, the perforated areas were obturated with calcium hydroxide; and group 3, calcium hydroxide plus growth factors was applied to the sites of perforation. All canals were filled by a lateral condensation technique. Animals were killed 12 wk later, and sections were hematoxylin & eosin-stained and immunostained for osteonectin. The amount of inflammation was evaluated histomorphologically. The one-way ANOVA test demonstrated that the three groups were significantly different from one another. In group 3 there was no inflammatory reaction of apical tissue, and the connective tissue adjacent to the newly formed hard tissue was strongly immunostained for osteonectin. Most sections in group 1 showed no apical healing. Moderate healing was found in group 2. In conclusion the combination of platelet-derived growth factor-BB and insulin-like growth factor-I with calcium hydroxide improved healing of apical perforation in dogs.

Transcription factor PU.1 mediates induction of c-fms in vascular smooth muscle cells: a mechanism for phenotypic change to phagocytic cells.

The macrophage colony-stimulating factor receptor encoded by the c-fms gene is expressed in vascular intimal smooth muscle cells isolated from atherosclerotic lesions. A combination of platelet-derived growth factor-BB and epidermal growth factor induces stable expression of c-fms in normal vascular medial smooth muscle cells. The mechanism by which these growth factors induce c-fms expression has now been investigated in an attempt to gain insight into the events that underlie the phenotypic conversion of vascular smooth muscle cells in atherosclerosis. Deletion analysis of the c-fms promoter revealed that the region including a binding site for transcription factor PU.1 was required for transcriptional activity in human aortic medial smooth muscle cells. Mutation in the PU.1 binding site markedly reduced promoter activity. Northern (RNA) blot analysis demonstrated that growth factors induced the expression of PU.1 mRNA in vascular medial smooth muscle cells and that PU.1 mRNA was expressed in vascular intimal smooth muscle cells. PU.1 antisense oligonucleotides inhibited growth factor-induced c-fms expression and foam cell formation. These results suggest that transcription factor PU.1 plays an essential role in the phenotypic conversion of vascular smooth muscle cells to macrophagelike cells by mediating the induction of c-fms.

Combination of platelet‐derived growth factor‐BB and insulin‐like growth factor‐I is more effective than platelet‐derived growth factor‐BB alone in stimulating complete healing of full‐thickness wounds in “older” diabetic mice

Platelet-derived growth factor and insulin-like growth factor-I have been shown to interact synergistically to enhance repair of skin wounds in normal healing swine. Platelet-derived growth factor alone has shown promise in treating human chronic ulcers. The objective of this study was to compare the wound healing effects of platelet-derived growth factor-BB alone with those of a combination of platelet-derived growth factor-BB and insulin-like growth factor-I in an improved model with the use of "older" animals with diabetes. Older diabetic (db/db) mice (>15 weeks of age) have less elevated insulin levels compared with young db/db mice. The serum insulin levels in the older animals is 1.0 to 2.5 times that of the nondiabetic animals, a similar increase to that which occurs in human patients with type II diabetes. Healing was evaluated in two studies involving a total of 104 animals. Treatment groups included the following: 4.0 microg/cm(2) of platelet-derived growth factor-BB, 40.0 microg/cm(2) of platelet-derived growth factor-BB, 4.0 microg/cm(2) of both platelet-derived growth factor-BB and insulin-like growth factor-I or vehicle. All growth factors were applied topically in a methylcellulose vehicle to full-thickness wounds every other day for 24 days. Efficacy end points were median and mean time to complete healing and rate of wound closure. The median time to complete healing for animals receiving the platelet-derived growth factor-BB/insulin-like growth factor-I combination was 38% and 33% faster (p < 0.001) than animals receiving 4.0 microg/cm(2) and 40.0 microg/cm(2) of platelet-derived growth factor-BB, respectively. The mean time to complete healing for platelet-derived growth factor/insulin-like growth factor-I treated animals was 31% and 29% faster (p < 0.001) than 4.0 microg/cm(2) and 40.0 microg/cm(2) platelet-derived growth factor-BB treated animals, respectively. Wounds treated with 4.0 microg/cm(2) platelet-derived growth factor-BB/insulin-like growth factor-I healed, on average, in 22 days compared with 31 days for 40.0 microg/cm(2) platelet-derived growth factor-BB alone and 38 days for vehicle. Also, platelet-derived growth factor-BB/insulin-like growth factor-I significantly improved the rate of wound closure throughout the duration of the studies compared with either dose of platelet-derived growth factor-BB alone (p < 0.005) or vehicle (p < 0.001). In conclusion, the data show that the combination of platelet-derived growth factor-BB and insulin-like growth factor-I is more effective than platelet-derived growth factor-BB alone at the doses tested or vehicle treatment in stimulating cutaneous wound healing in older, diabetic mice.

Hypoxia and platelet-derived growth factor-BB synergistically upregulate the expression of vascular endothelial growth factor in vascular smooth muscle cells

Vascular endothelial growth factor (VEGF) mRNA expression was analysed in rabbit vascular smooth muscle cells following exposure to hypoxia and platelet-derived growth factor-BB (PDGF-BB). Hypoxia potently upregulated VEGF mRNA steady-state levels in a time- and concentration-dependent manner reaching a maximum level (∼30-fold increase) after 12–24 h at 0% 0 2. In contrast, PDGF-BB caused a modest increase in VEGF expression. However, the combination of PDGF-BB and a threshold hypoxic stimulus (2.5% O 2 for 4 h) had a marked synergistic effect. Synergy between hypoxia and PDGF-BB was selective for VEGF expression as hypoxia had no effect on the PDGF-induced upregulation of the proto-oncogene c- myc. These results raise the possibility that hypoxia and PDGF-BB may act in concert to induce VEGF expression in the arterial wall during the development of atherosclerosis.

The combination of platelet‐derived growth factor‐BB and insulin‐like growth factor‐I stimulates bone repair in adult Yucatan miniature pigs

The combination of insulin-like growth factor-I and platelet-derived growth factor-BB has previously been shown to stimulate healing of soft tissue wounds and the formation of bone and ligament around teeth. The purpose of the present study was to evaluate the effects of platelet-derived growth factor-BB and insulin-like growth factor-I individually and in combination on the healing of osseous wounds. Four standardized cortical wounds were created in each tibia of 11 adult Yucatan miniature pigs. The wounds in one tibia per animal were treated with either purified recombinant human insulin-like growth factor-I, platelet-derived growth factor-BB, or both in a methylcellulose gel. The wounds in each contralateral tibia received placebo gel alone. Coded serial sections of each wound were evaluated by computer-aided histomorphometry 21 days after surgery. The area and perimeter of the newly formed mineralized callus, the thickness of the total callus, and the percentage of mineralized tissue within the callus were significantly increased compared with the values of matched controls only in wounds treated with a combination of insulin-like growth factor-I and platelet-derived growth factor-BB. No significant differences in the measured parameters of callus formation were found in wounds treated with either insulin-like growth factor-I or platelet-derived growth factor-BB alone. Cartilage was present only in sites treated with insulin-like growth factor-I alone. These results suggest that the combination of platelet-derived growth factor-BB and insulin-like growth factor-I stimulates bone formation in wounds in long bones of adult animals and that these growth factors act via different pathways during the repair process.

Transforming growth factor‐beta, basic fibroblast growth factor, and platelet‐derived growth factor‐BB interact to affect proliferation of clonally derived porcine satellite cells

Transforming growth factor beta-1 (TGF-beta) stimulated porcine satellite cell proliferation in basal serum-free medium by 25%, but inhibited growth in serum-containing medium by 58%. The effect of TGF-beta on cell proliferation in serum-free medium was examined in combination with the following human recombinant growth factors: platelet-derived growth factor-BB (PDGF), basic fibroblast growth factor (FGF), insulin-like growth factor I (IGF-I), and epidermal growth factor (EGF). TGF-beta inhibited PDGF-stimulated proliferation, enhanced FGF-stimulated proliferation, and had no effect on proliferation stimulated by IGF-I. The response of satellite cells to EGF and TGF-beta in serum-free medium was not different than TGF-beta alone. TGF-beta depressed proliferation stimulated by the following combinations of two growth factors: PDGF and IGF-I, PDGF and EGF, PDGF and FGF, and IGF-I and EGF. In combination with IGF-I and FGF, TGF-beta did not affect proliferation. TGF-beta inhibited proliferation stimulated by the combination of PDGF, EGF, and IGF-I, but had no effect on proliferation stimulated by combinations of three growth factors that included FGF. FGF stimulated proliferation in Minimum Essential Medium containing 10% porcine serum (MEM-10% PS) by 13% above control. When the combination of TGF-beta and FGF was added to MEM-10% PS, a 78% increase in proliferation was observed. Polyclonal antihuman PDGF-AB (this form neutralizes PDGF-AA, AB, and BB) reduced proliferation in MEM-10% PS by 44%. The combination of TGF-beta and anti-PDGF-AB reduced proliferation by 59%, indicating the effects were not additive. These data indicate that: (1) FGF and TGF-beta interact to increase proliferation of clonally derived porcine satellite cells, and (2) the inhibitory effect of TGF-beta on proliferation of clonally derived porcine satellite cells can be primarily attributed to a reduction in the mitogenic effects of PDGF.