Injection Of Platelet-derived Growth Factor Research Articles

Galectin-3 inhibition reduces fibrotic scarring and promotes functional recovery after spinal cord injury in mice

BackgroundIn the context of spinal cord injury (SCI), infiltrating macrophages assume prominence as the primary inflammatory cells within the lesion core, where the fibrotic scar is predominantly orchestrated by platelet-derived growth factor receptor beta (PDGFRβ+) fibroblasts. Galectin-3, a carbohydrate-binding protein of the lectin family, is notably expressed by infiltrating hematogenous macrophages and mediates cell-cell interactions. Although Galectin-3 has been shown to contribute to the endocytic internalization of PDGFRβ in vitro, its specific role in driving fibrotic scar formation after SCI has not been determined.MethodsWe employed a crush mid-thoracic (T10) SCI mouse model. Galectin-3 inhibition after SCI was achieved through intrathecal injection of the Galectin-3 inhibitor TD139 or in situ injection of lentivirus carrying Galectin-3-shRNA (Lv-shLgals3). A fibrosis-induced mice model was established by in situ injection of platelet-derived growth factor D (PDGFD) or recombinant Galectin-3 (rGalectin-3) into the uninjured spinal cord. Galectin-3 internalization experiments were conducted in PDGFRβ+ fibroblasts cocultured in conditioned medium in vitro.ResultsWe identified the spatial and temporal correlation between macrophage-derived Galectin-3 and PDGFRβ in fibroblasts from 3 to 56 days post-injury (dpi). Administration of TD139 via intrathecal injection or in situ injection of Lv-shLgals3 effectively mitigated fibrotic scar formation and extracellular matrix deposition within the injured spinal cord, leading to better neurological outcomes and function recovery after SCI. Furthermore, the fibrosis-inducing effects of exogenous PDGFD in the uninjured spinal cord could be blocked by TD139. In vitro experiments further demonstrated the ability of PDGFRβ+ fibroblasts to internalize Galectin-3, with Galectin-3 inhibition resulting in reduced PDGFRβ expression.ConclusionsOur finding underscores the pivotal role of macrophage-derived Galectin-3 in modulating the sustained internalized activation of PDGFRβ within fibroblasts, providing a novel mechanistic insight into fibrotic scarring post-SCI.

Intraovarian vascular enhancement via stromal injection of platelet-derived growth factors: Exploring subsequent oocyte chromosomal status and in vitro fertilization outcomes.

The inverse correlation between maternal age and pregnancy rate represents a major challenge for reproductive endocrinology. The high embryo ploidy error rate in failed in vitro fertilization (IVF) cycles reflects genetic misfires accumulated by older oocytes over time. Despite the application of different follicular recruitment protocols during IVF, gonadotropin modifications are generally futile in addressing such damage. Even when additional oocytes are retrieved, quality is frequently poor. Older oocytes with serious cytoplasmic and/or chromosomal errors are often harvested from poorly perfused follicles, and ovarian vascularity and follicular oxygenation impact embryonic chromosomal competency. Because stimulation regimens exert their effects briefly and immediately before ovulation, gonadotropins alone are an ineffective antidote to long-term hypoxic pathology. In contrast, the tissue repair properties (and particularly the angiogenic effects) of platelet-rich plasma (PRP) are well known, with applications in other clinical contexts. Injection of conventional PRP and/or its components (e.g., isolated platelet-derived growth factors as a cell-free substrate) into ovarian tissue prior to IVF has been reported to improve reproductive outcomes. Any derivative neovascularity may modulate oocyte competence by increasing cellular oxygenation and/or lowering concentrations of intraovarian reactive oxygen species. We propose a mechanism to support intrastromal angiogenesis, improved follicular perfusion, and, crucially, embryo ploidy rescue. This last effect may be explained by mRNA upregulation coordinated by PRP-associated molecular signaling, as in other tissue systems. Additionally, we outline an intraovarian injection technique for platelet-derived growth factors and present this method to help minimize reliance on donor oocytes and conventional hormone replacement therapy.

Comparison of intra-articular injection of plasma rich in growth factors versus hyaluronic acid following arthroscopy in the treatment of temporomandibular dysfunction: A randomised prospective study

PurposeThe main objective of our study was to evaluate the effectiveness of the injection of plasma rich in platelet-derived growth factors (PRGF) versus hyaluronic acid (HA) following arthroscopic surgery in patients diagnosed with internal derangement of the temporomandibular joint (TMJ) with osteoarthritis (OA). Materials and methodsA total of 100 patients were randomised into two study groups. Group A (n = 50) received an injection of PRGF, and Group B (n = 50) received an injection of HA. The mean age was 35.5 years (range 18–77 years), and 88% of the patients were women. The pain intensity (visual analogue scale) and the extent of maximum mouth opening before and after the procedure were statistically analysed. ResultsBetter results were observed in the group treated with PRGF, with a significant reduction in pain at 18 months, compared with HA treatment. Regarding mouth opening, an increase was observed in both groups, with no significant difference. ConclusionsThe injection of PRGF following arthroscopy is more effective than the injection of HA with respect to pain in patients with advanced internal derangement of the TMJ.

Platelet-Derived Growth Factor Preserves Retinal Synapses in a Rat Model of Ocular Hypertension.

Platelet-derived growth factor (PDGF) promotes neuronal survival in experimental glaucoma and recruits glial cells that regulate synapses. We investigated the effects of intravitreal PDGF on the inflammatory milieu and retinal synapses in the presence of raised IOP. Animals with laser-induced IOP elevation received intravitreal injections of either saline or 1.5 μg PDGF. At 7 days, a further intravitreal injection was administered so groups received "PDGF-saline" (n = 15), "PDGF-PDGF" (n = 13), or "saline-saline" (n = 20). Platelet-derived growth factor receptor activation was assessed after 2 weeks using Western blot for PI3 kinase. Immunohistochemistry was performed for markers of synapses in the inner plexiform layer (IPL): PSD-95, GluR1, SY38; RGCs: βIII-tubulin, and glial cells: Iba-1, CD45. Real-time quantitative polymerase chain reaction (qPCR) was performed for Arc, selp, MCP-1, IL-6, IL-10, and CX3CR1 (n = 13). A single injection of PDGF increased IPL synaptic density in high IOP eyes (PSD-95 = 8.65 ± 0.43, SY38 = 8.68 ± 0.51, GluR1 = 9.03 ± 0.60 puncta/μm3, P < 0.001) and expression of synaptic modulator Arc (6.92 ± 3.71-fold change/control, P < 0.05) in comparison with vehicle (PSD-95 = 4.59 ± 0.41, SY38 = 4.46 ± 0.38, GluR1 = 5.94 ± 0.50 puncta/μm3, Arc = 1.46 ± 0.31-fold/control). This was associated with more resident microglia (8.16 ± 1.34-fold change/control, P < 0.001) and infiltrating monocyte-derived macrophages in the retina as well as increased Selp expression (26.8 ± 14.12-fold change/control, P < 0.05). Optic nerve head (ONH) showed an increased microglia (saline = 1.44 ± 0.13 versus PDGF = 2.23 ± 0.18-fold change/control, P < 0.01) but not infiltrating macrophages. IL-10 expression was significantly increased in PDGF-treated eyes (5.43 ± 0.47-fold change/control, P < 0.05) relative to vehicle (2.51 ± 0.67-fold change/control). Platelet-derived growth factor increased microglial and monocyte-derived macrophage populations in the eye and protected intraretinal synapses from degeneration in our experimental glaucoma model.

Identification of retinal ganglion cell neuroprotection conferred by platelet-derived growth factor through analysis of the mesenchymal stem cell secretome

The development of neuroprotective strategies to attenuate retinal ganglion cell death could lead to novel therapies for chronic optic neuropathies such as glaucoma. Intravitreal transplantation of mesenchymal stem cells slows retinal ganglion cell death in models of optic nerve injury, but the mechanism of action remains unclear. Here we characterized the neuroprotective effects of mesenchymal stem cells and mesenchymal stem cell-derived factors in organotypic retinal explant culture and an in vivo model of ocular hypertensive glaucoma. Co-culture of rat and human bone marrow-derived mesenchymal stem cells with retinal explants increased retinal ganglion cell survival, after 7 days ex vivo, by ∼2-fold and was associated with reduced apoptosis and increased nerve fibre layer and inner plexiform layer thicknesses. These effects were not demonstrated by co-culture with human or mouse fibroblasts. Conditioned media from mesenchymal stem cells conferred neuroprotection, suggesting that the neuroprotection is mediated, at least partly, by secreted factors. We compared the concentrations of 29 factors in human mesenchymal stem cell and fibroblast conditioned media, and identified 11 enriched in the mesenchymal stem cell secretome. Treatment of retinal explants with a cocktail of these factors conferred retinal ganglion cell neuroprotection, with factors from the platelet-derived growth factor family being the most potent. Blockade of platelet-derived growth factor signalling with neutralizing antibody or with small molecule inhibitors of platelet-derived growth factor receptor kinase or downstream phosphatidylinositol 3 kinase eliminated retinal ganglion cell neuroprotection conferred by mesenchymal stem cell co-culture. Intravitreal injection of platelet-derived growth factor -AA or -AB led to profound optic nerve neuroprotection in vivo following experimental induction of elevated intraocular pressure. These data demonstrate that mesenchymal stem cells secrete a number of neuroprotective proteins and suggest that platelet-derived growth factor secretion in particular may play an important role in mesenchymal stem cell-mediated retinal ganglion cell neuroprotection. Furthermore, platelet-derived growth factor may represent an independent target for achieving retinal ganglion cell neuroprotection.

Convection-Enhanced Delivery of Topotecan into a PDGF-Driven Model of Glioblastoma Prolongs Survival and Ablates Both Tumor-Initiating Cells and Recruited Glial Progenitors

The contribution of microenvironment to tumor growth has important implications for optimizing chemotherapeutic response and understanding the biology of recurrent tumors. In this study, we tested the effects of locally administered topotecan on a rat model of glioblastoma that is induced by intracerebral injection of PDGF (platelet-derived growth factor)-IRES (internal ribosome entry site)-GFP (green fluorescent protein)-expressing retrovirus, treated the tumors by convection-enhanced delivery (CED) of topotecan (136 μmol/L) for 1, 4, or 7 days, and then characterized the effects on both the retrovirus-transformed tumor cells (GFP(+) cells) as well as the uninfected glial progenitor cells (GFP(-) cells) that are recruited to the tumor. Topotecan treatment reduced GFP(+) cells about 10-fold and recruited progenitors by about 80-fold while providing a significant survival advantage that improved with greater treatment duration. Regions of glial progenitor ablation occurred corresponding to the anatomic distribution of topotecan as predicted by MRI of a surrogate tracer. Histopathologic changes in recurrent tumors point to a decrease in recruitment, most likely due to the chemotherapeutic ablation of the recruitable progenitor pool.

Inflammation induced in rats by intraarticular injection of platelet-derived growth factor: [formula omitted]. Glaxo Research Laboratories, Research Triangle Park, NC 27709

Inflammation induced in rats by intraarticular injection of platelet-derived growth factor: [formula omitted]. Glaxo Research Laboratories, Research Triangle Park, NC 27709

Early metabolic effects of platelet-derived growth factor and transforming growth factor-beta in rat liver in vivo.

The short term metabolic effects of the in vivo administration of platelet-derived growth factor have been examined in the liver of the rat. Meal-fed male Wistar rats weighing between 150-180 g received an intraperitoneal injection of platelet-derived growth factor (17 units/100 g weight), transforming growth factor-beta (185 ng/100 g weight), or saline. At 5 min after injection, the livers were freeze-clamped. Samples of the tissue were subsequently assayed for metabolite content and enzyme activities. Platelet-derived growth factor injection caused an elevation in the liver content of pyruvate from 0.14 +/- 0.012 to 0.19 +/- 0.009 mumol/g wet weight liver (p less than or equal to 0.01) and an increase in the cytosolic phosphorylation potential [sigma ATP]/[sigma ADP][sigma Pi] from 6670 +/- 540 to 8970 +/- 750 (p less than or equal to 0.01). In addition an increase in the hepatic content of the hexose monophosphate pathway metabolites, 6-phosphogluconate (0.027 +/- 0.004 to 0.037 +/- 0.005 mumol/g wet weight) (p less than or equal to 0.05), ribulose 5-phosphate (0.013 +/- 0.001 to 0.017 +/- 0.001 mumol/g wet weight) (p less than or equal to 0.05) and combined sedoheptulose 7-phosphate and ribose 5-phosphate (0.052 +/- 0.007 to 0.062 +/- 0.004 mumol/g wet weight) (p less than or equal to 0.05) was observed. The elevation in the hexose monophosphate pathway metabolites resulted from a 1.3-fold elevation in the activity of glucose-6-phosphate dehydrogenase [EC 1.1.1.49] when measured in a crude homogenate. Kinetic analysis performed on partially purified glucose-6-phosphate dehydrogenase demonstrated no significant change in the Km of the enzyme for either NADP+ or glucose 6-phosphate, while a 2.4-fold increase in the Vmax was observed. In view of the rapidity of the change in total measured enzyme activity and increase in the Vmax of glucose-6-phosphate dehydrogenase, it is postulated that platelet-derived growth factor causes a covalent modification of the existing enzyme. Transforming growth factor-beta caused no change in the hepatic metabolite content in the treated animals when compared to saline treated controls.

An evidence for “response to injury” hypothesis

Role of platelet-derived growth factor (PDGF) in myointimal thickening described in “response to injury” hypothesis was investigated with artery of rats in culture and with air-injured artery of rats. PDGF promoted cell growth in ring preparation of carotid artery in culture denuded with citrate. It did not promote any cell growth in preparations without denudation. Trapidil, a PDGF antagonist, inhibited the cell growth promoted by PDGF in the denuded arterial ring. Systemic injection of PDGF was performed for 8 days to rats with thrombocytopenia induced by injections of anti-platelet serum. This treatment caused myointimal thickening of carotid artery 10 days after denudation by means of air injury. Trapidil at oral intake levels of 1, 3 and 30 mg/kg/day inhibited this change observed in denuded site of artery. Trapidil at oral intake of 6 mg/kg/day also inhibited myointimal thickening observed 15 days after denudation of carotid artery by air injury in normotensive and spontaneous hypertensive rats both with normal platelet counts. These results evidenced the role of PDGF in myointimal thickening described in “response to injury” hypothesis and clinical use of trapidil may be a new approach to the treatment of atherosclerosis.