Decoding Tumor Angiogenesis for Therapeutic Advancements: Mechanistic Insights

Tumor angiogenesis, the formation of new blood vessels within the tumor microenvironment, is considered a hallmark of cancer progression and represents a crucial target for therapeutic intervention. The tumor microenvironment is characterized by a complex interplay between proangiogenic and antiangiogenic factors, regulating the vascularization necessary for tumor growth and metastasis. The study of angiogenesis involves a spectrum of techniques, spanning from biomarker assessment to advanced imaging modalities. This comprehensive review aims to provide insights into the molecular intricacies, regulatory dynamics, and clinical implications of tumor angiogenesis. By delving into these aspects, we gain a deeper understanding of the processes driving vascularization in tumors, paving the way for the development of novel and effective antiangiogenic therapies in the fight against cancer.

The relationships of platelet-derived growth factor, microvascular proliferation, and tumor cell proliferation in canine high-grade oligodendrogliomas: Immunohistochemistry of 45 tumors and an AFOB-01 xenograft mouse model

High-grade oligodendroglioma (HGOG) is the most common type of glioma in dogs and expresses platelet-derived growth factor receptor-α (PDGFR-α). Microvascular proliferation is often observed in HGOG. Therefore, the present study investigated the functional relationships between PDGFR-α, microvascular proliferation, and tumor cell proliferation in canine HGOG. The expression of PDGFR-α and PDGF-subunit A (PDGF-A) in tumor cells, as well as endothelial cells and pericytes of tumor-associated microvascular proliferations, in 45 canine HGOGs were examined immunohistochemically. Microvascular proliferation was observed in 24/45 cases (53%). PDGFR-α expression in tumor cells and microvascular proliferations was observed in 45/45 (100%) and 2/24 cases (8%), respectively. Furthermore, PDGF-A expression in tumor cells and microvascular proliferations was detected in 13/45 (29%) and 24/24 cases (100%), respectively. In vitro, stimulation of the canine HGOG cell line AOFB-01 with PDGF-A showed that the doubling time of AOFB-01 cells was significantly shorter with PDGF-A than without PDGF-A. Crenolanib (a PDGFR inhibitor) inhibited AOFB-01 cell proliferation. In vivo, the AOFB-01 xenograft mouse model was treated with crenolanib. Tumor xenografts were smaller in crenolanib-treated mice than in untreated control mice. PDGFR-α expression in tumor cells and PDGF-A expression in microvascular proliferations and tumor cells suggest autocrine and paracrine effects of PDGF-A in canine HGOG. The results of in vitro assays indicate that canine HGOG expresses functional PDGFR-α, which responds to PDGF-A. Therefore, PDGF-A produced by microvascular proliferations and tumor cells may promote the proliferation of PDGFR-α-expressing tumor cells in canine HGOG. PDGFR-α signaling has potential as a therapeutic target.

Use of Concentrated Growth Factor (CGF) in Prosthetic-Guided Reconstruction on Two-Wall Bone Defect after Cystectomy: An Alternative to Traditional Regeneration

This clinical case report's objective was to describe an alternative technique executed to ensure bone regeneration after removing a cystic lesion in the upper jaw. The bone defect after the cystectomy was filled with autologous fibrin-rich clots containing concentrated growth factor (CGF). A 45-year-old female patient was presumed to have a cystic lesion with massive bone destruction on the vestibular and palatal walls between teeth 2.2 and 2.3. CGF was applied to fill the gap to promote the development of the bone. The tooth was asymptomatic and repair was still increasing steadily after a year, according to the results of the clinical and radiological follow-up assessment. This article describes a different way to treat a two-wall defect involving both the palatal and buccal bone, after removing a cystic lesion, with the use of CGF as an equivalent to the traditional use of autologous or heterologous bone. A promising substance for bone repair is CGF fibrin, which may encourage the growth of new bone in jaw deformities and promote bone tissue healing.

Platelet-Derived Growth Factor Nanocapsules with Tunable Controlled Release for Chronic Wound Healing

Chronic wounds have emerged as an increasingly critical clinical challenge over the past few decades, due to their increasing incidence and socioeconomic burdens. Platelet-derived growth factor (PDGF) plays a pivotal role in regulating processes such as fibroblast migration, proliferation, and vascular formation during the wound healing process. The delivery of PDGF offers great potential for expediting the healing of chronic wounds. However, the clinical effectiveness of PDGF in chronic wound healing is significantly hampered by its inability to maintain a stable concentration at the wound site over an extended period. In this study, a controlled PDGF delivery system based on nanocapsules is proposed. In this system, PDGF is encapsulated within a degradable polymer shell. The release rate of PDGF from these nanocapsules can be precisely adjusted by controlling the ratios of two crosslinkers with different degradation rates within the shells. As demonstrated in a diabetic wound model, improved therapeutic outcomes with PDGF nanocapsules (nPDGF) treatment are observed. This research introduces a novel PDGF delivery platform that holds promise for enhancing the effectiveness of chronic wound healing.

[Associations of serum neuromarkers with clinical features of Parkinson's disease]

OBJECTIVE

To evaluate the clinical and laboratory correlation of biomarkers with anti- and pro-apoptotic activity with the severity of motor and non-motor symptoms depending on the progression rate of Parkinson's disease (PD).

MATERIAL AND METHODS

A wide range of non-motor symptoms (emotional-affective, cognitive, psychotic and behavioral disorders, fatigue, sleep disorders and autonomic disorders) was evaluated using validated scales and a number of serum neuromarkers responsible for neuroplasticity and neuronal survival processes (BDNF, PDGF, cathepsin D) in 71 patients with PD (mean age 65 (55; 70) years, disease duration 7 (4; 9) years, age of onset 57 (49; 62) years).

RESULTS

The concentration of biomarkers (BDNF, PDGF and cathepsin D) was the lowest in the group of patients with a rapid PD progression rate (p<0.001, p=0.001 and p=0.031, respectively), the severity of motor and most non-motor symptoms was higher (p=0.023 and p=0.001, respectively) compared to middle and slow progression rate. There were correlations between BDNF concentration and the severity of depression (r=-0.63, p<0.001), apathy (r=-0.48, p<0.001), impulsive behavioral disorders (r=0.500, p<0.001), level of cognitive functions (r=0.54, p<0.001), motor symptoms (r=-0.43, p<0.001); between PDGF level and the severity of motor manifestations of PD (r=-0.30, p=0.011), depression (r=-0.70, p<0.001), apathy (r=-0.460, p<0.001), the degree of severity of behavioral disorders (r=0.742, p<0.001). No significant correlations were observed between the level of cathepsin D and the severity of clinical manifestations of PD, which indicates the connection of cathepsin D with the general pathogenesis of PD.

CONCLUSION

The possibility of using serum proteins of the neurotrophin subfamily and the protein associated with autophagy, cathepsin D, as biomarkers that determine the prognosis of PD, is considered.

Recent Advances in Liver Tissue Engineering as an Alternative and Complementary Approach for Liver Transplantation

Acute and chronic liver diseases cause significant morbidity and mortality worldwide, affecting millions of people. Liver transplantation is the primary intervention method, replacing a non-functional liver with a functional one. However, the field of liver transplantation faces challenges such as donor shortage, postoperative complications, immune rejection, and ethical problems. Consequently, there is an urgent need for alternative therapies that can complement traditional transplantation or serve as an alternative method. In this review, we explore the potential of liver tissue engineering as a supplementary approach to liver transplantation, offering benefits to patients with severe liver dysfunctions.

Vitreous Levels of Vascular Endothelial Growth Factor and Platelet-Derived Growth Factor in Patients with Proliferative Diabetic Retinopathy: A Clinical Correlation

Background: The global epidemic status of diabetic retinopathy (DR) and its burden presents an ongoing challenge to health-care systems. It is of great interest to investigate potential prognostic biomarkers of DR. Such markers could aid in detecting early stages of DR, predicting DR progression and its response to therapeutics. Herein, we investigate the prognostic value of intravitreal concentrations of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) in a DR cohort. Materials and methods: Vitreous sample acquisition was conducted at King Abdullah University Hospital (KAUH) between December 2020 and June 2022. Samples were obtained from any patient scheduled to undergo a pars plana vitrectomy (PPV) for any indication. Included patients were categorized into a DR group or a corresponding non-diabetic (ND) control group. Demographics, clinicopathological variables, standardized laboratory tests results, and optical coherence tomography (OCT) data were obtained for each included individual. Intravitreal concentrations of VEGF and PDGF were assessed using commercial enzyme-linked immunosorbent assay (ELISA). Results: A total of 80 eyes from 80 patients (DR group: n = 42 and ND control group: n = 38) were included in the analysis. The vitreous VEGF levels were significantly higher in the DR group compared to the ND control group (DR group 5744.06 ± 761.5 pg/mL versus ND control group 817.94 ± 403.1 pg/mL, p = 0.0001). In addition, the vitreous PDGF levels were also significantly higher in the DR group than those in the ND control group (DR group 4031.51 ± 410.2 pg/mL versus ND control group 2691.46 ± 821.0 pg/mL, p = 0.001). Bassline differences between test groups and clinical factors impacting VEGF and PDGF concentrations were investigated as well. Multiple regression analysis indicated PDGF as the sole independent risk factor affecting best-corrected visual acuity (BCVA) at the last follow-up visit: the higher the PDGF vitreous levels, the worst the BCVA. Conclusions: Vitreous concentrations of VEGF and PDGF are correlated with DR severity and may exhibit a possible prognostic potential value in DR. Further clinical and experimental data are warranted to confirm the observed findings and to help incorporate them into daily practice.

Human platelet-derived growth factor-BB (rhPDGF-BB) with collagen matrix for sinus elevation without using a bone graft

BACKGROUND

This case report involves a 38-year-old male who presented to the clinic after experiencing complications from a tooth extraction, including a dislodged root segment in the sinus, a sinus wall fenestration on the palate, a residual bone height (RBH) of 3 mm, and inadequate healing of the soft tissue. He presented for implant placement.

METHODS

Recombinant human platelet-derived growth factor-BB (rh-PDGF-BB) was applied to a wound dressing material and placed in the sinus cavity alongside a 4.8 × 10 mm dental implant (Straumann SP, Straumann, Andover, MA, USA.). As documented in the literature, a graftless sinus lift via a lateral window was performed using a split-thickness flap technique to elevate the sinus membrane, re-establish its integrity, and restore its barrier function.

RESULTS

An 8-month cone beam computed tomography assessment showed a 6.2 mm vertical bone gain and complete implant coverage.

CONCLUSION

This approach provided a successful alternative to shorten treatment duration and achieve favorable radiographic outcomes during early healing.

KEY POINTS

The use of rhPDGF-BB and a collagen matrix in a sinus lift procedure emerges as a practical therapeutic option when grafting might lack predictability and notably consume more treatment time, while also achieving the desired bone height when used with a simultaneously placed implant.

The expression of platelet-derived growth factor and its receptor in canine and feline meningiomas

Feline meningiomas usually have benign biological behavior, while canine and human meningiomas are often classified as grade 2 or 3. Activation of the platelet-derived growth factor (PDGF) and its receptor signal pathway through PDGFβ/Rβ autocrine and paracrine is considered to play an important role in the tumor proliferation and malignant transformation of human meningiomas. However, there have been few studies about the expression of these molecules in canine meningiomas and no studies about their expression in feline meningiomas. We analyzed the PDGFα/Rα and PDGFβ/Rβ expression in canine and feline meningiomas by immunohistochemistry and western blotting. Immunohistochemically, most canine meningiomas showed the expression of PDGFα (42/44; 95.5%), PDGFRα (44/44; 100%) and PDGFRβ (35/44; 79.5%), and a few showed the expression of PDGFβ (8/44; 18.2%). In contrast, feline meningiomas were immunopositive for PDGFRα and PDGFRβ in all cases (14/14; 100%), while no or a few cases expressed PDGFα (0/14; 0%) and PDGFβ (2/14; 14.3%). Western blotting revealed specific bands for PDGFα, PDGFRα and PDGFRβ, but not for PDGFβ in a canine meningioma. In a feline meningioma, specific bands for PDGFRα and PDGFRβ were detected, but not for PDGFα and PDGFβ. These results suggested that canine meningiomas commonly express PDGFα/Rα, and thus autocrine or paracrine PDGFα/Rα signaling may be involved in their initiation and progression. Moreover, PDGF negativity may be related to benign biological behavior and a low histopathological grade in feline meningioma.

Twenty-five years of recombinant human growth factors rhPDGF-BB and rhBMP-2 in oral hard and soft tissue regeneration

Contemporary oral tissue engineering strategies involve recombinant human growth factor approaches to stimulate diverse cellular processes including cell differentiation, migration, recruitment, and proliferation at grafted areas. Recombinant human growth factor applications in oral hard and soft tissue regeneration have been progressively researched over the last 25 years. Growth factor-mediated surgical approaches aim to accelerate healing, tissue reconstruction, and patient recovery. Thus, regenerative approaches involving growth factors such as recombinant human platelet-derived growth factor-BB (rhPDGF-BB) and recombinant human bone morphogenetic proteins (rhBMPs) have shown certain advantages over invasive traditional surgical approaches in severe hard and soft tissue defects. Several clinical studies assessed the outcomes of rhBMP-2 in diverse clinical applications for implant site development and bone augmentation. Current evidence regarding the clinical benefits of rhBMP-2 compared to conventional therapies is inconclusive. Nevertheless, it seems that rhBMP-2 can promote faster wound healing processes and enhance de novo bone formation, which may be particularly favorable in patients with compromised bone healing capacity or limited donor sites. rhPDGF-BB has been extensively applied for periodontal regenerative procedures and for the treatment of gingival recessions, showing consistent and positive outcomes. Nevertheless, current evidence regarding its benefits at implant and edentulous sites is limited. The present review explores and depicts the current applications, outcomes, and evidence-based clinical recommendations of rhPDGF-BB and rhBMPs for oral tissue regeneration.

Comparative efficacy of growth factor therapy in healing diabetes-related foot ulcers: A network meta-analysis of randomized controlled trials

INTRODUCTION

This study examined the relative efficacy of growth factor therapies in healing diabetes-related foot ulcers (DFU).

METHODS

PubMed and Cochrane databases were searched for randomized controlled trials testing growth factor therapies for treating DFU. The primary outcome was complete wound closure. Results were reported as relative risk (RR) ± 95% credible intervals (CrI). The risk of bias was assessed using Cochrane's RoB-2 tool.

RESULTS

A total of 31 RCTs involving 2174 participants were included. Only 13 of the trials (n = 924) reported on the aetiology of the ulcers (85.4% neuropathic and 14.6% ischaemic). Epidermal growth factor (RR 3.83; 95% CrI 1.81, 9.10), plasma-rich protein (PRP) (RR 3.36; 95% CrI 1.66, 8.03) and platelet-derived growth factor (PDGF) (RR 2.47; 95% CrI 1.23, 5.17) significantly improved the likelihood of complete ulcer healing compared to control. Sub-analyses suggested that PRP (3 trials - RR 9.69; 95% CrI 1.37, 103.37) and PDGF (6 trials - RR 2.22; 95% CrI 1.12, 5.19) significantly improved the likelihood of wound closure amongst trial mainly recruiting participants with neuropathic ulcers. Eleven trials had a low risk of bias, 9 had some concerns and 11 had a high risk of bias. Sub-analysis of trials with a low risk of bias suggested that none of the growth factors significantly improved ulcer healing compared with control.

DISCUSSION

This network meta-analysis found low-quality evidence that Epidermal growth factor, PRP and PDGF therapy improved DFU healing likelihood compared with control. Larger well-designed trials are needed.

Molecular Docking Study of New Sorafenib Analogues as Platelet-Derived Growth Factor Receptor Inhibitors for the Treatment of Cancer

Cancer is a disease triggered by an uncontrolled growth of a group of cells usually from a single cell. Chemotherapy is a common and systematic therapy that involves the use of anticancer drugs also known as chemotherapeutical agents to treat cancer. Tyrosine kinases are a subset of protein kinases that are a family of over 90 enzymes that selectively phosphorylate tyrosine residues in various substrates. Receptors with internal tyrosine kinase activity mediate the actions of several growth factors, differentiation factors, and hormones, resulting in the reproduction and differentiation of the affected cells. In the fight against cancer, the platelet-derived growth factor receptor has emerged as a novel target via inhibition of this receptor resulting in the inhibition of tyrosine kinase cascade. Docking investigations were conducted using the Genetic Optimization for Ligand Docking (GOLD) Suite (v. 5.7.1) from the Cambridge Crystallographic Data Center. A high-definition X-ray crystallography of the platelet-derived growth factor protein [Protein Data Bank (PDB) ID 6JOL] was downloaded from the website PDB with a resolution of 2 A. Compounds II, III, VII, and VIII have greater binding energies than the GOLD standard medication sorafenib, which gives Piecewise Linear Potential (PLP) fitness value (85.3). Other ligands exhibit good inhibitory action and docking scores comparable to that of the reference ligand sorafenib.

The Role of Platelet-Rich Plasma Therapy in Joint Arthroplasty A Mini-Review

Orthobiologics are playing an increasingly large role in the clinical setting across multiple fields of surgery. Particularly, in the field of orthopedic surgery, the employment of platelet-rich plasma (PRP) therapy in total joint arthroscopy (TJA) has become popular for its prompted benefits of controlling pain, blood loss, and increased wound healing. PRP was originally used for thrombolytic conditions, however, the aforementioned potential benefits have led to its increased use across various fields of medicine including dermatology, neurosurgery, orthopedics, and sports medicine. Currently, there is a persisting gap in the literature surrounding the mechanism of action of PRP, as well as its true role in increasing positive patient outcomes in the context of TJA. Thus, this review aims to briefly highlight the physiological mechanisms underlining PRP therapy, evaluate recent preclinical and clinical data about its effects on TJA patient outcomes, and to describe its concomitant use in novel orthopedic-applications.

Effects of Intravitreal Ranibizumab Injection on Peripheral Retinal Microcirculation and Cytokines in Branch Retinal Vein Occlusion with Macular Edema

Background and Objectives: To investigate peripheral blood flow in retinal vessels and vessel diameters after intravitreal ranibizumab injection (IRI) and the relationship between these parameters and cytokines in branch retinal vein occlusion (BRVO) with macular edema. Materials and Methods: We assessed relative flow volume (RFV) and the width of the main and branch retinal arteries and veins in the occluded and non-occluded regions before and after IRI in 37 patients with BRVO and macular edema. Measurements were made using laser speckle flowgraphy (LSFG). When performing IRI, we obtained samples of aqueous humor and analyzed them using the suspension array method to evaluate vascular endothelial growth factor (VEGF), placental growth factor (PlGF), platelet-derived growth factor (PDGF)-AA, soluble intercellular adhesion molecule (sICAM)-1, monocyte chemoattractant protein 1 (MCP-1), interleukin (IL)-6, IL-8, and interferon-inducible 10-kDa protein (IP-10). Results: In both retinal regions, before and after IRI, the RFV in the main artery and vein showed a significant correlation with the summed RFV in the respective branch vessels 1 and 2. In the occluded region, the RFV in the main vein was significantly negatively correlated with MCP-1, PDGF-AA, IL-6, and IL-8; the RFV in branch vein 1 was significantly negatively correlated with PlGF, MCP-1, IL-6, and IL-8; PDGF-AA was significantly negatively correlated with the width of the main and branch veins; and the RFVs of the main artery and vein decreased significantly from before to 1 month after IRI. Conclusions: Contrary to expectations, the study found that anti-VEGF therapy does not affect RFV in arteries and veins in patients with BRVO and macular edema. Furthermore, retinal blood flow is poor in patients with high MCP-1, IL-6, and IL-8. Finally, high PDGF-AA may result in smaller venous diameters and reduced retinal blood flow.

Effects of Topography and PDGF on the Response of Corneal Keratocytes to Fibronectin-Coated Surfaces

During corneal wound healing, corneal keratocytes are exposed to both biophysical and soluble cues that cause them to transform from a quiescent state to a repair phenotype. How keratocytes integrate these multiple cues simultaneously is not well understood. To investigate this process, primary rabbit corneal keratocytes were cultured on substrates patterned with aligned collagen fibrils and coated with adsorbed fibronectin. After 2 or 5 days of culture, keratocytes were fixed and stained to assess changes in cell morphology and markers of myofibroblastic activation by fluorescence microscopy. Initially, adsorbed fibronectin had an activating effect on the keratocytes as evidenced by changes in cell shape, stress fiber formation, and expression of alpha-smooth muscle actin (α-SMA). The magnitude of these effects depended upon substrate topography (i.e., flat substrate vs aligned collagen fibrils) and decreased with culture time. When keratocytes were simultaneously exposed to adsorbed fibronectin and soluble platelet-derived growth factor-BB (PDGF-BB), the cells elongated and had reduced expression of stress fibers and α-SMA. In the presence of PDGF-BB, keratocytes plated on the aligned collagen fibrils elongated in the direction of the fibrils. These results provide new information on how keratocytes respond to multiple simultaneous cues and how the anisotropic topography of aligned collagen fibrils influences keratocyte behavior.

The effect of cilostazol on the platelet-derived growth factor-beta/beta isoform reduction on venous hyperplasia in an experimental balloon-induced injury model

BACKGROUND

Intimal hyperplasia is the response to endothelial injury. Platelet-derived growth factor is released early and favors the formation of intimal hyperplasia. Although multiple treatments, from open surgery to endovascular techniques, have been used they remain controversial. There is currently interest in developing pharmacological strategies to address this pathology. Local vascular inflammation induced by vessel barotrauma generates intimal hyperplasia due to mechanical stress over the venous endothelium. Cilostazol is a selective phosphodiesterase type 3 (PDE3) selective inhibitor with a regulatory effect over intimal hyperplasia. The objective was to investigate cilostazol's role in inhibiting smooth muscle cell proliferation due to changes in the expression and release of PDGF-BB isoform and the effect on developing IH using an experimental model of vascular barotrauma (balloon-induced injury model).

METHODS

We included 12 New Zealand rabbits. The balloon-induced injury model (BIIM) and experimental group cilostazol (20 mg/kg/day) included 6 rabbits each. Contralateral veins from 6 rabbits used in BIIM model has been taken as control group. We measured and compared the expression of PDGF-BB and the development of IH. A pathologist board chooses a PDGFRα antibody to localized its expression by immunohistochemistry analysis. Subsequently, using an automated immunohistochemical staining machine, the PDGFR expression was evaluated using a Zeiss Primo Star 4 light microscope.

RESULTS

The measurement obtained in the intimal layer was: 126.12 μm2 in the CG, 232 μm2 in the BIIM group, and 178 μm2 in the EG. A statistically significant difference was observed. Baseline serum concentrations of PDGF-BB in the BIIM group were 0.22 pg/mL. At 12 h 0.42 pg/mL, and 0.17 pg/mL at seven days. In the experimental group, the basal levels were 0.33 pg/mL. With the use of cilostazol, a lower peak was obtained at 12 h (0.08 pg/mL). This difference was statistically significant.

CONCLUSIONS

Cilostazol induced a significant reduction of IH caused by barotrauma in the venous endothelium, which correlates with decrease in the PDGF-BB in serum. This could be attributed to the pharmacologic effect on PDGFR expression.

Differentiation of Peritubular Myoid-Like Cells from Human Induced Pluripotent Stem Cells

Infertility affects 10-15% of couples, with half attributed to male factors. An improved understanding of the cell-type-specific dysfunction contributing to male infertility is needed to improve available therapies; however, human testicular tissues are difficult to obtain for research purposes. To overcome this, researchers have begun to use human induced pluripotent stem cells (hiPSCs) to generate various testis-specific cell types in vitro. Peritubular myoid cells (PTMs) are one such testicular cell type that serves a critical role in the human testis niche but, to date, have not been derived from hiPSCs. This study set forth to generate a molecular-based differentiation method for deriving PTMs from hiPSCs, mirroring in vivo patterning factors. Whole transcriptome profiling and quantitative polymerase chain reaction (qPCR) show that this differentiation method is sufficient to derive cells with PTM-like transcriptomes, including upregulation of hallmark PTM functional genes, secreted growth and matrix factors, smooth muscle, integrins, receptors, and antioxidants. Hierarchical clustering shows that they acquire transcriptomes similar to primary isolated PTMs, and immunostaining shows the acquisition of a smooth muscle phenotype. Overall, these hiPSC-PTMs will allow in vitro study of patient-specific PTM development and function in spermatogenesis and infertility.

Supramolecular Hydrogel Microspheres of Platelet-Derived Growth Factor Mimetic Peptide Promote Recovery from Spinal Cord Injury

Neural stem cells (NSCs) are considered to be prospective replacements for neuronal cell loss as a result of spinal cord injury (SCI). However, the survival and neuronal differentiation of NSCs are strongly affected by the unfavorable microenvironment induced by SCI, which critically impairs their therapeutic ability to treat SCI. Herein, a strategy to fabricate PDGF-MP hydrogel (PDGF-MPH) microspheres (PDGF-MPHM) instead of bulk hydrogels is proposed to dramatically enhance the efficiency of platelet-derived growth factor mimetic peptide (PDGF-MP) in activating its receptor. PDGF-MPHM were fabricated by a piezoelectric ceramic-driven thermal electrospray device, had an average size of 9 μm, and also had the ability to activate the PDGFRβ of NSCs more effectively than PDGF-MPH. In vitro, PDGF-MPHM exerted strong neuroprotective effects by maintaining the proliferation and inhibiting the apoptosis of NSCs in the presence of myelin extracts. In vivo, PDGF-MPHM inhibited M1 macrophage infiltration and extrinsic or intrinsic cells apoptosis on the seventh day after SCI. Eight weeks after SCI, the T10 SCI treatment results showed that PDGF-MPHM + NSCs significantly promoted the survival of NSCs and neuronal differentiation, reduced lesion size, and considerably improved motor function recovery in SCI rats by stimulating axonal regeneration, synapse formation, and angiogenesis in comparison with the NSCs graft group. Therefore, our findings provide insights into the ability of PDGF-MPHM to be a promising therapeutic agent for SCI repair.

Effectiveness of BMP-2 and PDGF-BB Adsorption onto a Collagen/Collagen-Magnesium-Hydroxyapatite Scaffold in Weight-Bearing and Non-Weight-Bearing Osteochondral Defect Bone Repair: In Vitro, Ex Vivo and In Vivo Evaluation

Despite promising clinical results in osteochondral defect repair, a recently developed bi-layered collagen/collagen-magnesium-hydroxyapatite scaffold has demonstrated less optimal subchondral bone repair. This study aimed to improve the bone repair potential of this scaffold by adsorbing bone morphogenetic protein 2 (BMP-2) and/or platelet-derived growth factor-BB (PDGF-BB) onto said scaffold. The in vitro release kinetics of BMP-2/PDGF-BB demonstrated that PDGF-BB was burst released from the collagen-only layer, whereas BMP-2 was largely retained in both layers. Cell ingrowth was enhanced by BMP-2/PDFG-BB in a bovine osteochondral defect ex vivo model. In an in vivo semi-orthotopic athymic mouse model, adding BMP-2 or PDGF-BB increased tissue repair after four weeks. After eight weeks, most defects were filled with bone tissue. To further investigate the promising effect of BMP-2, a caprine bilateral stifle osteochondral defect model was used where defects were created in weight-bearing femoral condyle and non-weight-bearing trochlear groove locations. After six months, the adsorption of BMP-2 resulted in significantly less bone repair compared with scaffold-only in the femoral condyle defects and a trend to more bone repair in the trochlear groove. Overall, the adsorption of BMP-2 onto a Col/Col-Mg-HAp scaffold reduced bone formation in weight-bearing osteochondral defects, but not in non-weight-bearing osteochondral defects.

The Interplay Between Cholesterol and Amyloid-β on HT22 Cell Viability, Morphology, and Receptor Tyrosine Kinase Signaling

BACKGROUND

There is a lack of understanding in the molecular and cellular mechanisms of Alzheimer's disease that has hindered progress on therapeutic development. The focus has been on targeting toxic amyloid-β (Aβ) pathology, but these therapeutics have generally failed in clinical trials. Aβ is an aggregation-prone protein that has been shown to disrupt cell membrane structure in molecular biophysics studies and interfere with membrane receptor signaling in cell and animal studies. Whether the lipid membrane or specific receptors are the primary target of attack has not been determined.

OBJECTIVE

This work elucidates some of the interplay between membrane cholesterol and Aβ42 on HT22 neuronal cell viability, morphology, and platelet-derived growth factor (PDGF) signaling pathways.

METHODS

The effects of cholesterol depletion by methyl-β-cyclodextrin followed by treatment with Aβ and/or PDGF-AA were assessed by MTT cell viability assays, western blot, optical and AFM microscopy.

RESULTS

Cell viability studies show that cholesterol depletion was mildly protective against Aβ toxicity. Together cholesterol reduction and Aβ42 treatment compounded the disruption of the PDGFα receptor activation. Phase contrast optical microscopy and live cell atomic force microscopy imaging revealed that cytotoxic levels of Aβ42 caused morphological changes including cell membrane damage, cytoskeletal disruption, and impaired cell adhesion; cell damage was ameliorated by cellular cholesterol depletion.

CONCLUSIONS

Cholesterol depletion impacted the effects of Aβ42 on HT22 cell viability, morphology, and receptor tyrosine kinase signaling.

PDGF-BB-enriched collagen matrix to treat multiple gingival recessions with the tunneled coronally advanced flap

BACKGROUND

With technological advancements in reconstructive periodontology, traditional protocols for the treatment of gingival recessions (GRs) can be challenged. This manuscript presents preliminary findings of a novel minimally-invasive approach for the regenerative treatment of multiple adjacent GR defects.

METHODS

Two healthy adults were treated as part of this study. Multiple adjacent GRs in both subjects (1 in the mandible, and 1 in the maxilla) were treated employing a tunneled coronally advanced flap (TCAF) design, with the application of a cross-linked collagen matrix (CCM) that was enriched with recombinant human platelet-derived growth factor-BB (PDGF-BB) that was also applied on the prepared root surfaces. Clinical, ultrasonographic, esthetic, and patient-reported outcomes were observed at approximately 6- and 18-month time points.

RESULTS

All sites healed uneventfully after the treatments. Complete root coverage was achieved and maintained throughout the follow-up observations, from 6 to 18 months. Patients reported minimal discomfort and reduction of dentinal hypersensitivity at the augmented sites. The areas augmented with CCM + PDGF-BB revealed an increased soft tissue thickness relative to baseline (pretreatment) measures, as well as reduction in the level of the facial bone dehiscences.

CONCLUSION

This article describes the success of two cases of a novel minimally invasive regenerative approach for the treatment of multiple adjacent GR defects by the TCAF, using a CCM loaded with PDGF-BB. This approach offers potential as a minimally-invasive method to repair multiple adjacent GRs.

Relationship between the Responsiveness of Amyloid β Protein to Platelet Activation by TRAP Stimulation and Brain Atrophy in Patients with Diabetes Mellitus

Type 2 DM is a risk factor for dementia, including Alzheimer's disease (AD), and is associated with brain atrophy. Amyloid β protein (Aβ) deposition in the brain parenchyma is implicated in the neurodegeneration that occurs in AD. Platelets, known as abundant storage of Aβ, are recognized to play important roles in the onset and progression of AD. We recently showed that Aβ negatively regulates platelet activation induced by thrombin receptor-activating protein (TRAP) in healthy people. In the present study, we investigated the effects of Aβ on the TRAP-stimulated platelet activation in DM patients, and the relationship between the individual responsiveness to Aβ and quantitative findings of MRI, the volume of white matter hyperintensity (WMH)/intracranial volume (IC) and the volume of parenchyma (PAR)/IC. In some DM patients, Aβ reduced platelet aggregation induced by TRAP, while in others it was unchanged or rather enhanced. The TRAP-induced levels of phosphorylated-Akt and phosphorylated-HSP27, the levels of PDGF-AB and the released phosphorylated-HSP27 correlated with the degree of platelet aggregability. The individual levels of not WMH/IC but PAR/IC was correlated with those of TRAP-stimulated PDGF-AB release. Collectively, our results suggest that the reactivity of TRAP-stimulated platelet activation to Aβ differs in DM patients from healthy people. The anti-suppressive feature of platelet activation to Aβ might be protective for brain atrophy in DM patients.

The critical issue linking lipids and inflammation: Clinical utility of stopping oxidative stress

The formation of an atheroma begins when lipoproteins become trapped in the intima. Entrapped lipoproteins become oxidized and activate the innate immune system. This immunity represents the primary association between lipids and inflammation. When the trapping continues, the link between lipids and inflammation becomes chronic and detrimental, resulting in atherosclerosis. When entrapment ceases, the association between lipids and inflammation is temporary and healthy, and the atherogenic process halts. Therefore, the link between lipids and inflammation depends upon lipoprotein retention in the intima. The entrapment is due to electrostatic forces uniting apolipoprotein B to polysaccharide chains on intimal proteoglycans. The genetic transformation of contractile smooth muscle cells in the media into migratory secretory smooth muscle cells produces the intimal proteoglycans. The protein, platelet-derived growth factor produced by activated platelets, is the primary stimulus for this genetic change. Oxidative stress is the main stimulus to activate platelets. Therefore, minimizing oxidative stress would significantly reduce the retention of lipoproteins. Less entrapment decreases the association between lipids and inflammation. More importantly, it would halt atherogenesis. This review will analyze oxidative stress as the critical link between lipids, inflammation, and the pathogenesis of atherosclerosis. Through this perspective, we will discuss stopping oxidative stress to disrupt a harmful association between lipids and inflammation. Numerous therapeutic options will be discussed to mitigate oxidative stress. This paper will add a new meaning to the Morse code distress signal SOS-stopping oxidative stress.

Recombinant human platelet-derived growth factor improves root coverage of a collagen matrix for multiple adjacent gingival recessions: A triple-blinded, randomized, placebo-controlled trial

AIM

To evaluate the efficacy of recombinant human platelet-derived growth factor (rhPDGF)-BB combined with a cross-linked collagen matrix (CCM) for the treatment of multiple adjacent gingival recession type 1 defects (MAGRs) in combination with the coronally advanced flap (CAF).

MATERIALS AND METHODS

Thirty patients were enrolled in this triple-blind, randomized, placebo-controlled trial and treated with either CAF + CCM + rhPDGF, or CAF + CCM + saline. The primary outcome was mean root coverage (mRC) at 6 months. Complete root coverage, gain in gingival thickness (GT), keratinized tissue width, volumetric and ultrasonographic changes, and patient-reported outcome measures were also assessed. Mixed-modelling regression analyses were used for statistical comparisons.

RESULTS

At 6 months, the mRC of the CCM + rhPDGF and CCM alone groups were 88.25% and 77.72%, respectively (p = .02). A significant gain in GT was consistently observed for both treatment arms, and more so for the patients receiving the matrix containing rhPDGF through time (0.51 vs. 0.80 mm, on average, p = .01). The rhPDGF + CCM treated patients presented greater volume gain, higher soft tissue thickness, and a superior aesthetic score.

CONCLUSION

rhPDGF enhances the clinical, volumetric, and aesthetic outcomes of MAGRs above the results achieved with CAF + CCM alone (ClinicalTrials.gov NCT04462237).

Melatonin promotes the proliferation of primordial germ cell-like cells derived from porcine skin-derived stem cells: A mechanistic analysis

In vitro differentiation of stem cells into functional gametes remains of great interest in the biomedical field. Skin-derived stem cells (SDSCs) are an adult stem cells that provides a wide range of clinical applications without inherent ethical restrictions. In this paper, porcine SDSCs were successfully differentiated into primordial germ cell-like cells (PGCLCs) in conditioned media. The PGCLCs were characterized in terms of cell morphology, marker gene expression, and epigenetic properties. Furthermore, we also found that 25 μM melatonin (MLT) significantly increased the proliferation of the SDSC-derived PGCLCs while acting through the MLT receptor type 1 (MT1). RNA-seq results found the mitogen-activated protein kinase (MAPK) signaling pathway was more active when PGCLCs were cultured with MLT. Moreover, the effect of MLT was attenuated by the use of S26131 (MT1 antagonist), crenolanib (platelet-derived growth factor receptor inhibitor), U0126 (mitogen-activated protein kinase kinase inhibitor), or CCG-1423 (serum response factor transcription inhibitor), suggesting that MLT promotes the proliferation processes through the MAPK pathway. Taken together, this study highlights the role of MLT in promoting PGCLCs proliferation. Importantly, this study provides a suitable in vitro model for use in translational studies and could help to answer numerous remaining questions related to germ cell physiology.

Platelet-derived growth factors from a single donor by apheresis and one freeze-thaw cycle for treating medication-related osteonecrosis of the jaw

Aim: To assess whether the use of allogeneic platelet-derived growth factors could serve as a feasible, effective and safe biological therapy for the treatment of medication-related osteonecrosis of the jaw (MRONJ). Materials & methods: Patients with multiple myeloma and MRONJ were included and treated with allogeneic platelet-rich plasma, continued for between 6 and 18 weeks (mean: 9). Results: We observed a treatment success rate of 87.5% (p < 0.05). Assessing the association between healing and treatment duration, we observed a statistically significant relationship (χ² = 8.00; p = 0.018; Cramer's V = 1), confirming that healing was very closely related to the duration of the treatment. Conclusion: Allogeneic platelet-rich plasma could be a recommended treatment for MRONJ. Future research with a large sample to validate our findings is required.

Regnase-1 Prevents Pulmonary Arterial Hypertension Through mRNA Degradation of Interleukin-6 and Platelet-Derived Growth Factor in Alveolar Macrophages

BACKGROUND

Pulmonary arterial hypertension (PAH) is a type of pulmonary hypertension (PH) characterized by obliterative pulmonary vascular remodeling, resulting in right-sided heart failure. Although the pathogenesis of PAH is not fully understood, inflammatory responses and cytokines have been shown to be associated with PAH, in particular, with connective tissue disease-PAH. In this sense, Regnase-1, an RNase that regulates mRNAs encoding genes related to immune reactions, was investigated in relation to the pathogenesis of PH.

METHODS

We first examined the expression levels of ZC3H12A (encoding Regnase-1) in peripheral blood mononuclear cells from patients with PH classified under various types of PH, searching for an association between the ZC3H12A expression and clinical features. We then generated mice lacking Regnase-1 in myeloid cells, including alveolar macrophages, and examined right ventricular systolic pressures and histological changes in the lung. We further performed a comprehensive analysis of the transcriptome of alveolar macrophages and pulmonary arteries to identify genes regulated by Regnase-1 in alveolar macrophages.

RESULTS

ZC3H12A expression in peripheral blood mononuclear cells was inversely correlated with the prognosis and severity of disease in patients with PH, in particular, in connective tissue disease-PAH. The critical role of Regnase-1 in controlling PAH was also reinforced by the analysis of mice lacking Regnase-1 in alveolar macrophages. These mice spontaneously developed severe PAH, characterized by the elevated right ventricular systolic pressures and irreversible pulmonary vascular remodeling, which recapitulated the pathology of patients with PAH. Transcriptomic analysis of alveolar macrophages and pulmonary arteries of these PAH mice revealed that Il6, Il1b, and Pdgfa/b are potential targets of Regnase-1 in alveolar macrophages in the regulation of PAH. The inhibition of IL-6 (interleukin-6) by an anti-IL-6 receptor antibody or platelet-derived growth factor by imatinib but not IL-1β (interleukin-1β) by anakinra, ameliorated the pathogenesis of PAH.

CONCLUSIONS

Regnase-1 maintains lung innate immune homeostasis through the control of IL-6 and platelet-derived growth factor in alveolar macrophages, thereby suppressing the development of PAH in mice. Furthermore, the decreased expression of Regnase-1 in various types of PH implies its involvement in PH pathogenesis and may serve as a disease biomarker, and a therapeutic target for PH as well.

Correlation between platelet-derived growth factor-B gene polymorphism and coronary heart disease

OBJECT

The aim of the present work was to investigate the correlation of plasma platelet-derived growth factor (PDGF)-BB level and single nucleotide polymorphism (SNP, rs1800817 and rs2285094) of PDGF-B gene with the onset and stability condition of coronary heart disease (CHD).

METHODS

Totally, 335 subjects were included in and divided into CHD (n = 247) and control group (n = 88) according to coronary angiography. Besides, the patients in the CHD group were divided into acute coronary syndrome (ACS) group (n = 165) and stable angina pectoria (SAP) group (n = 82), based on CHD stability condition. The plasma PDGF-BB level was measured by ELISA, and the genotype of PDGF-B was examined through qPCR assay.

RESULTS

The PDGF-BB level was positively correlated with hsCRP level (r = 0.149, p < 0.05). The genotype frequencies of SNP rs1800817 and rs2285094 match Hardy-Weinberg equilibrium. There was weak linkage disequilibrium between SNP rs1800817 and rs2285094: D' = 0.419, r²  = 0.04, which has no correlation with CHD. There was no statistical difference in plasma PDGF-BB level among different genotypes in rs1800817 and rs2285094. There were no differences in the plasma PDGF-BB level among patients with any genotype of SNP rs1800817 and rs2285094, no matter how it was grouped. Logistic regression results indicated that the plasma PDGF-BB level was the independent risk factor of CHD onset (OR = 1.003, 95% CI 1.001-1.006, p = 0.014).

CONCLUSIONS

High plasma PDGF-BB level is the risk factor of CHD and has correlation with instability of CHD. The plasma PDGF-BB level change may be related to inflammatory response. PDGF-B gene rs1800817 and rs2285094 polymorphisms are not correlated with CHD.

Penttinen syndrome-associated PDGFRB Val665Ala variant causes aberrant constitutive STAT1 signalling

Penttinen syndrome is a rare progeroid disorder caused by mutations in platelet‐derived growth factor (PDGF) receptor beta (encoded by the PDGFRB proto‐oncogene) and characterized by a prematurely aged appearance with lipoatrophy, skin lesions, thin hair and acro‐osteolysis. Activating mutations in PDGFRB have been associated with other human diseases, including Kosaki overgrowth syndrome, infantile myofibromatosis, fusiform aneurysms, acute lymphoblastic leukaemia and myeloproliferative neoplasms associated with eosinophilia. The goal of the present study was to characterize the PDGFRB p.Val665Ala variant associated with Penttinen syndrome at the molecular level. This substitution is located in a conserved loop of the receptor tyrosine kinase domain. We observed that the mutant receptor was expressed at a lower level but showed constitutive activity. In the absence of ligand, the mutant activated STAT1 and elicited an interferon‐like transcriptional response. Phosphorylation of STAT3, STAT5, AKT and phospholipase Cγ was weak or undetectable. It was devoid of oncogenic activity in two cell proliferation assays, contrasting with classical PDGF receptor oncogenic mutants. STAT1 activation was not sensitive to ruxolitinib and did not rely on interferon‐JAK2 signalling. Another tyrosine kinase inhibitor, imatinib, blocked signalling by the p.Val665Ala variant at a higher concentration compared with the wild‐type receptor. Importantly, this concentration remained in the therapeutic range. Dasatinib, nilotinib and ponatinib also inhibited the mutant receptor. In conclusion, the p.Val665Ala variant confers unique features to PDGF receptor β compared with other characterized gain‐of‐function mutants, which may in part explain the particular set of symptoms associated with Penttinen syndrome.

Adult-induced genetic ablation distinguishes PDGFB roles in blood-brain barrier maintenance and development

Platelet-derived growth factor B (PDGFB) released from endothelial cells is indispensable for pericyte recruitment during angiogenesis in embryonic and postnatal organ growth. Constitutive genetic loss-of-function of PDGFB leads to pericyte hypoplasia and the formation of a sparse, dilated and venous-shifted brain microvasculature with dysfunctional blood-brain barrier (BBB) in mice, as well as the formation of microvascular calcification in both mice and humans. Endothelial PDGFB is also expressed in the adult quiescent microvasculature, but here its importance is unknown. We show that deletion of Pdgfb in endothelial cells in 2-months-old mice causes a slowly progressing pericyte loss leading, at 12-18 months of age, to ≈50% decrease in endothelial:pericyte cell ratio, ≈60% decrease in pericyte longitudinal capillary coverage and >70% decrease in pericyte marker expression. Similar to constitutive loss of Pdgfb, this correlates with increased BBB permeability. However, in contrast to the constitutive loss of Pdgfb, adult-induced loss does not lead to vessel dilation, impaired arterio-venous zonation or the formation of microvascular calcifications. We conclude that PDFGB expression in quiescent adult microvascular brain endothelium is critical for the maintenance of pericyte coverage and normal BBB function, but that microvessel dilation, rarefaction, arterio-venous skewing and calcification reflect developmental roles of PDGFB.

Amyloid β protein negatively regulates human platelet activation induced by thrombin receptor-activating protein

Amyloid β protein deposition in cerebral vessels, a characteristic of Alzheimer's disease, is a risk factor for intracerebral hemorrhage. Amyloid β protein directly modulates human platelet function; however, the exact mechanism of action is unclear. Therefore, we investigated the effects of amyloid β protein on human platelet activation using an aggregometer with laser scattering. Amyloid β protein decreased platelet aggregation induced by thrombin receptor-activating protein, but not by collagen and ADP. Amyloid β protein also suppressed platelet aggregation induced by SCP0237 and A3227. Platelet-derived growth factor-AB secretion and phosphorylated-heat shock protein 27 release by thrombin receptor-activating protein were inhibited by amyloid β protein. Additionally, thrombin receptor-activating protein-induced phosphorylation of JNK and p38 MAP kinase was reduced by amyloid β protein. Collectively, our results strongly suggest that amyloid β protein negatively regulates protease-activated receptor-elicited human platelet activation. These findings may indicate a cause of intracerebral hemorrhage due to amyloid β protein.

Platelet-Derived Growth Factor Induces SASP-Associated Gene Expression in Human Multipotent Mesenchymal Stromal Cells but Does Not Promote Cell Senescence

Activation of multipotent mesenchymal stromal cells (MSCs) is a central part of tissue response to damage. Platelet-derived growth factor (PDGF-BB), which is abundantly released in the damaged area, potently stimulates the proliferation and migration of MSCs. Recent evidence indicates that tissue injury is associated with the accumulation of senescent cells, including ones of MSC origin. Therefore, we hypothesized that PDGF-BB induces MSC senescence. To evaluate mechanisms of early activation of MSCs by PDGF-BB, we performed transcriptome profiling of human MSCs isolated from adipose tissue after exposure to PDGF-BB for 12 and 24 h. We demonstrated that PDGF-BB induced the expression of several genes encoding the components of senescence-associated secretory phenotype (SASP) in MSCs such as plasminogen activator inhibitor-1 (PAI-1), urokinase-type plasminogen activator and its receptor (uPA and uPAR), and some matrix metalloproteases. However, further experimental validation of transcriptomic data clearly indicated that PDGF-BB exerted mitogenic and pro-migratory effects on MSCs, and augmented their pro-angiogenic activity, but did not significantly stimulate MSC senescence.

Intravitreous treatment of severe ocular von Hippel-Lindau disease using a combination of the VEGF inhibitor, ranibizumab and PDGF inhibitor, E10030: Results from a phase 1/2 clinical trial

BACKGROUND

Treatment options for severe ocular von Hippel-Lindau (VHL) disease are limited. This trial evaluated preliminary safety and potential efficacy of combination intravitreous injection with ranibizumab, a vascular endothelial growth factor (VEGF) inhibitor, and E10030, a PDGF inhibitor, for eyes with VHL disease-associated retinal hemangioblastoma (RH) not amenable or responsive to thermal laser photocoagulation.

METHODS

This was a prospective, single-arm, open-label phase 1/2 study, comprised of three adults with VHL-associated RH and vision loss. Intravitreous injections of ranibizumab (0.5 mg) and E10030 (1.5 mg) were given unilaterally every 4 weeks in the study eye through 16 weeks, then every 8 weeks through 48 weeks. Supplementary standard care therapies were allowed without restriction after 40 weeks. The primary outcome was the ocular and systemic adverse effect profile at 52 weeks. Secondary outcomes included changes in best-corrected visual acuity (BCVA), RH size, exudation, epiretinal proliferation and retinal traction, and need for ablative treatment of RH or ocular surgery at week 52.

RESULTS

Three participants each received nine injections prior to week 52 and were followed for 104 weeks. One participant manifested mild episodic ocular hypertension in the study eye. Change in BCVA in the study eye at week 52 for the three participants was -5, -12 and +2 letters. No reduction in RH size was measured at 52 weeks. Variable mild improvements in exudation in two participants at week 16 were not sustained through week 52.

CONCLUSIONS

Combination intravitreous injection with ranibizumab and E10030 demonstrated a reasonable preliminary safety profile, but limited treatment effect.

Diabetes Impaired Ischemia-Induced PDGF (Platelet-Derived Growth Factor) Signaling Actions and Vessel Formation Through the Activation of Scr Homology 2-Containing Phosphatase-1

Objective

Critical limb ischemia is a major complication of diabetes characterized by insufficient collateral vessel development and proper growth factor signaling unresponsiveness. Although mainly deactivated by hypoxia, phosphatases are important players in the deregulation of proangiogenetic pathways. Previously, SHP-1 (Scr homology 2-containing phosphatase-1) was found to be associated with the downregulation of growth factor actions in the diabetic muscle. Thus, we aimed to gain further understanding of the impact of SHP-1 on smooth muscle cell (SMC) function under hypoxic and diabetic conditions.

Approach and Results

Despite being inactivated under hypoxic conditions, high glucose level exposure sustained SHP-1 phosphatase activity in SMC and increased its interaction with PDGFR (platelet-derived growth factor receptor)-β, thus reducing PDGF proangiogenic actions. Overexpression of an inactive form of SHP-1 fully restored PDGF-induced proliferation, migration, and signaling pathways in SMC exposed to high glucose and hypoxia. Nondiabetic and diabetic mice with deletion of SHP-1 specifically in SMC were generated. Ligation of the femoral artery was performed, and blood flow was measured for 4 weeks. Blood flow reperfusion, vascular density and maturation, and limb survival were all improved while vascular apoptosis was attenuated in diabetic SMC-specific SHP-1 null mice as compared to diabetic mice.

Conclusions

Diabetes and high glucose level exposure maintained SHP-1 activity preventing hypoxia-induced PDGF actions in SMC. Specific deletion of SHP-1 in SMC partially restored blood flow reperfusion in the diabetic ischemic limb. Therefore, local modulation of SHP-1 activity in SMC could represent a potential therapeutic avenue to improve the proangiogenic properties of SMC under ischemia and diabetes.

Role of NEAT1/MiR-9-5p/SLC26A2 Pathway on Human Airway Smooth Muscle Cell

PURPOSE

Asthma is a serious inflammatory disease of the respiratory system in which airway smooth muscle cells (ASMCs) play a key role. This study aimed to investigate the expression of SLC26A2 in human ASMCs (HASMCs) and the regulatory mechanism of SLC26A2 in the proliferation and inflammatory factor production of HASMCs.

MATERIALS AND METHODS

We obtained the asthma-associated differential mRNA SLC26A2 by bioinformatics analysis in childhood acute asthma samples. To investigate its role in airway inflammation and airway remodeling, we treated HASMCs with platelet-derived growth factor (PDGF) in an in vitro model and determined SLC26A2 expression in cells using western blotting. Cell proliferation was detected by MTT and EdU assays, and cell contractile phenotype marker proteins were measured. Cell migration and production of inflammatory factors were determined by Transwell and ELISA assays. Additionally, the upstream regulatory miRNA and LncRNA of SLC26A2 were identified by bioinformatics, luciferase reporter gene, and RIP analyses.

RESULTS

SLC26A2 was significantly upregulated in bioinformatics analysis of pediatric asthma-related sample. PDGF treatment up-regulated SLC26A2 expression in HASMCs, whereas the knockdown of SLC26A2 inhibited PDGF-stimulated proliferation, migration, and production of inflammatory factors, and enhanced the expression of cell contractile phenotype marker proteins in HASMCs. Luciferase reporter and RIP experiments validated that NEAT1 targeted miR-9-5p to regulate SLC26A2, thereby influencing the biological function of PDGF-induced HASMCs.

CONCLUSION

These findings indicate that NEAT1-mediated miR-9-5p targeting of SLC26A2 inhibits the PDGF-induced proliferation and production of inflammatory factors in HASMCs. These findings highlight potential therapeutic targets for asthma and airway inflammation.

Prenatal Molecular Hydrogen Administration Ameliorates Several Findings in Nitrofen-Induced Congenital Diaphragmatic Hernia

Oxidative stress plays a pathological role in pulmonary hypoplasia and pulmonary hypertension in congenital diaphragmatic hernia (CDH). This study investigated the effect of molecular hydrogen (H₂), an antioxidant, on CDH pathology induced by nitrofen. Sprague-Dawley rats were divided into three groups: control, CDH, and CDH + hydrogen-rich water (HW). Pregnant dams of CDH + HW pups were orally administered HW from embryonic day 10 until parturition. Gasometric evaluation and histological, immunohistochemical, and real-time polymerase chain reaction analyses were performed. Gasometric results (pH, pO_2, and pCO₂ levels) were better in the CDH + HW group than in the CDH group. The CDH + HW group showed amelioration of alveolarization and pulmonary artery remodeling compared with the CDH group. Oxidative stress (8-hydroxy-2′-deoxyguanosine-positive-cell score) in the pulmonary arteries and mRNA levels of protein-containing pulmonary surfactant that protects against pulmonary collapse (surfactant protein A) were significantly attenuated in the CDH + HW group compared with the CDH group. Overall, prenatal H₂ administration improved respiratory function by attenuating lung morphology and pulmonary artery thickening in CDH rat models. Thus, H₂ administration in pregnant women with diagnosed fetal CDH might be a novel antenatal intervention strategy to reduce newborn mortality due to CDH.

Recombinant platelet-derived growth factor-BB alleviates osteoarthritis in a rat model by decreasing chondrocyte apoptosis in vitro and in vivo

Osteoarthritis (OA) is a common joint disease that mainly affects the diarthrodial joints. Treatments for OA include non‐pharmacological interventions, topical and oral therapies, intra‐articular therapies and joint surgery. However, all the treatments mentioned above mainly aim to control the symptoms instead of improving or reversing the joint condition. In this research, we observed the effect of recombinant platelet‐derived growth factor (PDGF)‐BB on OA in a monosodium iodoacetate (MIA)–induced rat model and revealed the possible mechanisms. In vitro, the level of inflammation in the chondrocytes was gradually alleviated, and the apoptosis rate was gradually decreased by PDGF‐BB at increasing concentrations. The levels of p‐p38, Bax and caspase‐3 decreased, and the level of p‐Erk increased with increasing PDGF‐BB concentration. In vivo, PDGF‐BB could significantly reverse chondrocyte and matrix loss. Furthermore, high concentrations of PDGF‐BB could alleviate cartilage hyperplasia to remodel the tissue. The level of collagen II was up‐regulated, and the levels of collagen X and apoptosis were down‐regulated by increasing concentrations of PDGF‐BB. In conclusion, recombinant PDGF‐BB alleviated OA by down‐regulating caspase‐3‐dependent apoptosis. The effects of PDGF‐BB on OA mainly include inhibiting chondrocyte loss, reducing cartilage hyperplasia and osteophyte formation, and regulating collagen anabolism.

Analysis and comparison of autologous platelet-rich plasma preparation systems used in the treatment of enthesopathies: A preliminary study

BACKGROUND

Autologous platelet-rich plasma (PRP) injection is an alternative but widely accepted method for the treatment of degenerative changes in tendon attachments known as enthesopathies. The PRP is considered a safe source for high concentrations of the growth factors involved in the healing process. Despite initial promising outcomes, many recent studies report conflicting results for this treatment. This may be due to differences in the concentrations of platelets and growth factors in PRPs obtained using different methods.

OBJECTIVES

The aim of this study was to compare PRP preparation systems in terms of morphotic components and selected growth factors to find the most appropriate procedure for the treatment of enthesopathies.

MATERIAL AND METHODS

Whole blood samples from 6 healthy male volunteers were collected. Using different commercial kits (Mini GPS III System, Arthrex ACP, and Xerthra, Dr. PRP), 4 PRPs were prepared from the blood of each participant. All samples were analyzed for the content of morphotic components and the following growth factors: transforming growth factor-β1 (TGF-β1), epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), and platelet-derived growth factor AA (PDGF-AA).

RESULTS

The Mini GPS III produced PRP with the highest concentration of platelets and white blood cells (WBC) compared to the other systems included in the study. Significant differences in the levels of EGF and PDGF-AA were found only between the Mini GPS III and Arthrex ACP. There was positive correlation between the content of platelets and the levels of PDGF-AA and EGF. The red blood cells (RBC) concentration positively correlated with PDGF-AA, EGF and VEGF.

CONCLUSIONS

This study showed differences between the morphotic components and levels of selected growth factors in PRP obtained with the different preparation methods. Due to insufficient data, we cannot argue for or against any of the studied protocols for the treatment of enthesopathy. Further studies on a larger population are required to validate our results.

PDGF-BB regulates the transformation of fibroblasts into cancer-associated fibroblasts via the lncRNA LURAP1L-AS1/LURAP1L/IKK/IκB/NF-κB signaling pathway

The most abundant cells in the tumor microenvironment are cancer-associated fibroblasts (CAFs). They play an important role in oral squamous cell carcinoma (OSCC) angiogenesis, invasion and metastasis. Platelet-derived growth factor (PDGF)-BB has an obvious regulating effect on the formation of CAFs through binding to PDGF receptor (PDGFR)-β, but the role of long non-coding (lnc)RNA in PDGF-BB-induced transformation of fibroblasts into CAFs remains poorly understood. Using an lncRNA ChIP, 370 lncRNA transcripts were identified to be significantly and differentially expressed between fibroblasts and PDGF-BB-induced fibroblasts, including 240 upregulated lncRNAs and 130 downregulated lncRNAs, indicating that lncRNAs are involved in the regulation of the transformation of CAFs. Previous studies have shown that the nuclear factor (NF)-κB signaling pathway plays an important role in the activation of CAFs. Dual-luciferase reporter assay and co-immunoprecipitation were conducted to confirm that the leucine-rich adaptor protein 1-like (LURAP1L), which is the target of lncRNA LURAP1L antisense RNA 1 (LURAP1L-AS1) had a positive regulatory effect on I-κB kinase (IKK)/NF-κB signaling. Therefore, LURAP1L-AS1 was selected and PDGF-BB was demonstrated to upregulate the expression of LURAP1L-AS1 and LURAP1L, which was reversed by a PDGFR-β inhibitor. Subsequently, knocking down LURAP1L-AS1 suppressed the expression of PDGF-BB-induced fibroblast activation marker protein α-smooth muscle actin, fibroblast activation protein-α, PDGFR-β and phosphorylated (p)-PDGFR-β. IKKα, p-IĸB and p-NF-κB were downregulated by the knockdown of LURAP1L-AS1 and upregulated by overexpression of LURAP1L-AS1. The present study indicates that LURAP1L-AS1/LURAP1L/IKK/IĸB/NF-κB plays an important regulatory role in PDGF-BB-induced fibroblast activation and may become a potential target for the treatment of OSCC.

Glycosylation at Asn254 Is Required for the Activation of the PDGF-C Protein

Platelet-derived growth factor C (PDGF-C) is a member of the PDGF/VEGF (vascular endothelial growth factor) family, which includes proteins that are well known for their mitogenic effects on multiple cell types. Glycosylation is one of the most important forms of posttranslational modification that has a significant impact on secreted and membrane proteins. Glycosylation has many well-characterized roles in facilitating protein processing and contributes to appropriate folding, conformation, distribution, and stability of proteins that are synthesized intracellularly in the endoplasmic reticulum (ER) and Golgi apparatus. Although the general process and functions of glycosylation are well documented, there are most likely others yet to be discovered, as the glycosylation of many potential substrates has not been characterized. In this study, we report that the PDGF-C protein is glycosylated at three sites, including Asn25, Asn55, and Asn254. However, we found that mutations at any of these sites do not affect the protein expression or secretion. Similarly, disruption of PDGF-C glycosylation had no impact on its progression through the ER and Golgi apparatus. However, the introduction of a mutation at Asn254 (N254 A) prevents the activation of full-length PDGF-C and its capacity for signaling via the PDGF receptor. Our findings reveal that glycosylation affects PDGF-C activation rather than the protein synthesis or processing. This study characterizes a crucial modification of the PDGF-C protein, and may shed new light on the process and function of glycosylation.

Many roles for oligodendrocyte precursor cells in physiology and pathology

Oligodendrocyte precursor cells (OPCs) are a fourth resident glial cell population in the mammalian central nervous system. They are evenly distributed throughout the gray and white matter and continue to proliferate and generate new oligodendrocytes (OLs) throughout life. They were understudied until a few decades ago when immunolabeling for NG2 and platelet-derived growth factor receptor alpha revealed cells that are distinct from mature OLs, astrocytes, neurons, and microglia. In this review, we provide a summary of the known properties of OPCs with some historical background, followed by highlights from recent studies that suggest new roles for OPCs in certain pathological conditions.

Cerebrospinal fluid cytokines and metalloproteinases in cerebral amyloid angiopathy-related inflammation

OBJECTIVES

To clarify pathomechanisms of cerebral amyloid angiopathy-related inflammation/vasculitis (CAA-ri).

METHODS

We collected cerebrospinal fluid (CSF) samples of nine patients with CAA-ri of before (acute CAA-ri group) and after treatment (post-treatment CAA-ri group) and nine patients with CAA (CAA without inflammation group). We examined anti-amyloid β protein (Aβ) antibody titer by ELISA, and measured 27 Cytokines, nine matrix metalloproteinases (MMPs), and four tissue inhibitors of MMPs (TIMPs) by multiplexed fluorescent bead-based immunoassay.

RESULTS

We demonstrated TIMP-2 (median) in CSF of the acute CAA-ri group (30,994.49 pg/ml, p = 0.007) and the post-treatment CAA-ri group (36,430.97 pg/ml, p = 0.001) was significantly elevated compared to that of the CAA without inflammation group (22,013.58 pg/ml). TIMP-1 was also higher in the post-treatment CAA-ri group than that in the CAA without inflammation group (58,167.75 pg/ml vs. 45,770.03 pg/ml, p = 0.005). There was a significant positive correlation between TIMP-1 and anti-Aβ antibodies in CAA-ri (r_s  = 0.900, p = 0.037). Median MMP-2 tended to be higher in the acute and post-treatment CAA-ri groups (10,619.82 pg/ml and 8396.98 pg/ml, respectively) than in the CAA without inflammation group (4436.34 pg/ml). Platelet-derived growth factor (PDGF)-BB levels before treatment were higher than those after treatment (median, 12.66 pg/ml vs. 6.39 pg/ml; p = 0.011) and correlated with the titer of anti-Aβ antibodies (r_s  =0.900, p = 0.037).

CONCLUSIONS

Elevated levels of MMP-2, TIMP-1, and TIMP-2 might be related to the development of CAA-ri. Elevation of PDGF-BB could be a useful marker for clinical diagnosis of CAA-ri.

Reactive sulfur species inhibit the migration of PDGF-treated vascular smooth muscle cells by blocking the reactive oxygen species-regulated Akt signaling pathway

Vascular smooth muscle cell (VSMC) migration contributes to vascular remodeling after injury, whereas oxidative stress generated through dysfunctional redox homeostasis induces hypermigration, leading to arteriosclerosis. Platelet-derived growth factor (PDGF)-induced reactive oxygen species (ROS) serve as intracellular signaling molecules in VSMCs. Reactive sulfur species (RSS) may serve as a biological defense system because of the antioxidative properties of highly nucleophilic sulfane sulfur. However, insufficient information is available on its function in PDGF-induced VSMC migration. Here we show that PDGF significantly increased the levels of intracellular sulfane sulfur and that intracellular sulfane sulfur donors, donor 5a and Na₂S₄, inhibited the increase in ROS levels in PDGF-treated VSMCs and inhibited their migration. Consistent with the migration results, sulfane sulfur donors inhibited Akt phosphorylation, a downstream signaling molecule in the PDGF cascade, without affecting the autophosphorylation of PDGF receptor-β. Further, sulfane sulfur donors inhibited vinculin and paxillin recruitment to the leading edge of VSMCs in response to PDGF to decrease focal adhesion formation. These findings suggest that RSS are required for PDGF-stimulated VSMC migration through the regulation of the ROS-regulated Akt pathway, which may contribute to focal adhesion formation. Our findings provide insight into RSS as novel regulators of vascular redox homeostasis.

Platelet-Derived Growth Factor Stimulated Migration of Bone Marrow Mesenchymal Stem Cells into an Injectable Gelatin-Hydroxyphenyl Propionic Acid Matrix

Bone marrow mesenchymal stem cells (bMSCs) are responsible in the repair of injured tissue through differentiation into multiple cell types and secretion of paracrine factors, and thus have a broad application profile in tissue engineering/regenerative medicine, especially for the musculoskeletal system. The lesion due to injury or disease may be a closed irregular-shaped cavity deep within tissue necessitating an injectable biomaterial permissive of host (endogenous) cell migration, proliferation and differentiation. Gelatin-hydroxyphenyl propionic acid (Gtn-HPA) is a natural biopolymer hydrogel which is covalently cross-linked by horseradish peroxidase (HRP) and hydrogen peroxide (H₂O₂) in situ and can be delivered to the lesion by needle injection. Growth factors and cytokines can be directly incorporated into the gel or into nano- and micro-particles, which can be employed for sustained release of biomolecules while maintaining their bioactivity. In this study, we selected polyelectrolyte complex nanoparticles (PCNs) prepared with dextran sulfate and chitosan as the carrier for platelet-derived growth factor (PDGF)-BB and stromal cell-derived factor (SDF)-1α, which have been tested effectively in recruiting stem cells. Our in vitro results showed a high degree of viability of bMSCs through the process of Gtn-HPA covalent cross-linking gelation. The Gtn-HPA matrix was highly permissive of bMSC migration, proliferation, and differentiation. PDGF-BB (20 ng/mL) directly incorporated into the gel and, alternatively, released from PCNs stimulated bMSC migration and proliferation. There were only small differences in the results for the direct incorporation of PDGF into the gel compared with its release from PCNs, and for increased doses of the growth factor (200 ng/mL and 2 µg/mL). In contrast, SDF-1α elicited an increase in migration and proliferation only when released from PCNs; its effect on migration was notably less than PDGF-BB. The in vitro results demonstrate that PDGF-BB substantially increases migration of bMSCs into Gtn-HPA and their proliferation in the gel, and that these benefits can be derived from incorporation of a relatively low dose of the growth factor directly into the gel. These findings commend the use of Gtn-HPA/PDGF-BB as an injectable therapeutic agent to treat defects in musculoskeletal tissues.

Molecular similarity between the mechanisms of epithelial fusion and fetal wound healing during the closure of the caudal neural tube in mouse embryos

BACKGROUND

Neural tube (NT) closure is a complex developmental process that takes place in the early stages of embryogenesis and that is a key step in neurulation. In mammals, the process by which the neural plate generates the NT requires organized cell movements and tissue folding, and it terminates with the fusion of the apposed ends of the neural folds.

RESULTS

Here we describe how almost identical cellular and molecular machinery is used to fuse the spinal neural folds as that involved in the repair of epithelial injury in the same area of the embryo. For both natural and wound activated closure of caudal neural tissue, hyaluronic acid and platelet-derived growth factor signaling appear to be crucial for the final fusion step.

CONCLUSIONS

There seems to be no general wound healing machinery for all tissues but rather, a tissue-specific epithelial fusion machinery that embryos activate when necessary after abnormal epithelial opening.

Expression of growth factors and their receptors in the primary renal cell carcinoma: new data and review

Introduction

The aim of our study was to investigate expression levels and the prognostic value of multiple growth factors and their receptors in the primary tumor cells of renal cell carcinoma (RCC).

Material and methods

Expression of vascular endothelial growth factor (VEGF)A, fibroblast growth factor (FGF)2, vascular endothelial growth factor receptor (VEGFR)1, VEGFR2, FGFR1, FGFR2, platelet-derived growth factor receptor (PDGFR)α, and PDGFRβ was investigated in 65 primary RCC specimens by immuhistochemical staining using the appropriate antibodies. Expression levels were evaluated by the semi-quantitative method. A search for correlations of expression levels of investigated growth factors and receptors with RCC features and patients outcomes was performed.

Results

Expression of all growth factors and their receptors was detected both on the surface and in the cytoplasm of the primary tumor cells in RCC patients. The expression of all analyzed factors was interconnected. FGFR2 expression correlated with the largest number of other growth factors and receptors. A strong correlation was revealed between high expression of the studied markers, high Fuhrman grade, and advanced RCC stages. In a univariate analysis overexpression of VEGFR2 (p <0.0001) and FGFR2 (p = 0.014) had negative influence on cancer-specific survival.

Conclusions

Expression of growth factors and tyrosine kinase receptors in the primary tumor cells is strongly interconnected and associated with unfavorable features of RCC.

Surfactant Protein A, a Novel Regulator for Smooth Muscle Phenotypic Modulation and Vascular Remodeling-Brief Report

OBJECTIVE

The objective of this study is to determine the role of SPA (surfactant protein A) in vascular smooth muscle cell (SMC) phenotypic modulation and vascular remodeling. Approach and Results: PDGF-BB (Platelet-derived growth factor-BB) and serum induced SPA expression while downregulating SMC marker gene expression in SMCs. SPA deficiency increased the contractile protein expression. Mechanistically, SPA deficiency enhanced the expression of myocardin and TGF (transforming growth factor)-β, the key regulators for contractile SMC phenotype. In vivo, SPA was induced in medial and neointimal SMCs following mechanical injury in both rat and mouse carotid arteries. SPA knockout in mice dramatically attenuated the wire injury-induced intimal hyperplasia while restoring SMC contractile protein expression in medial SMCs. These data indicate that SPA plays an important role in SMC phenotype modulation and vascular remodeling in vivo.

CONCLUSIONS

SPA is a novel protein factor modulating SMC phenotype. Blocking the abnormal elevation of SPA may be a potential strategy to inhibit the development of proliferative vascular diseases.

Exogenous platelet-derived growth factor improves neurovascular unit recovery after spinal cord injury

The blood-spinal cord barrier plays a vital role in recovery after spinal cord injury. The neurovascular unit concept emphasizes the relationship between nerves and vessels in the brain, while the effect of the blood-spinal cord barrier on the neurovascular unit is rarely reported in spinal cord injury studies. Mouse models of spinal cord injury were established by heavy object impact and then immediately injected with platelet-derived growth factor (80 μg/kg) at the injury site. Our results showed that after platelet-derived growth factor administration, spinal cord injury, neuronal apoptosis, and blood-spinal cord barrier permeability were reduced, excessive astrocyte proliferation and the autophagy-related apoptosis signaling pathway were inhibited, collagen synthesis was increased, and mouse locomotor function was improved. In vitro, human umbilical vein endothelial cells were established by exposure to 200 μM H₂O₂. At 2 hours prior to injury, in vitro cell models were treated with 5 ng/mL platelet-derived growth factor. Our results showed that expression of blood-spinal cord barrier-related proteins, including Occludin, Claudin 5, and β-catenin, was significantly decreased and autophagy was significantly reduced. Additionally, the protective effects of platelet-derived growth factor could be reversed by intraperitoneal injection of 80 mg/kg chloroquine, an autophagy inhibitor, for 3 successive days prior to spinal cord injury. Our findings suggest that platelet-derived growth factor can promote endothelial cell repair by regulating autophagy, improve the function of the blood-spinal cord barrier, and promote the recovery of locomotor function post-spinal cord injury. Approval for animal experiments was obtained from the Animal Ethics Committee, Wenzhou Medical University, China (approval No. wydw2018-0043) in July 2018.