Platelet-derived Growth Factor Production Research Articles

Ambroxol-induced leukocytoclastic vasculitis: A case report and literature review

Cutaneous leukocytoclastic vasculitis (LCV) that primarily affects the skin, can be idiopathic or linked to infections, autoimmune diseases, neoplasms, and medications. An immune complex-mediated vasculitis of the dermal capillaries and venules is the histological hallmark of LCV, a small vessel vasculitis. This case report describes a 36-year previously healthy man who was presented to the outpatient department (OPD) with complaints of edema and development of numerous reddish-purple patches (caused by petechiae) after intake of cough syrup containing ambroxol. Ambroxol affects human monocytic cells THP-1, and prevents the generation of platelet-derived growth factor (PDGF)-AB that is produced by lipopolysaccharide (LPS) by inhibiting the expression of PDGF-A messenger Ribonucleic acid (RNA). An extracellular signal-regulated kinase (ERK) on p44/42 is activated by LPS, and ambroxol reduces this activation. In addition, 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one (PD 98059), a Mitogen-Activated Protein Kinase Inhibitors (MEK), MEK-1-specific inhibitor, prevents p44/42 ERK activation and PDGF synthesis brought on by LPS. Megakaryocytes, erythrocytes, leukocytes, and their progenitors are stimulated to multiply by PDGF to the numerous endogenous growth factors that mesenchymal stem and stromal cells secrete. Ambroxol reduces the number of megakaryocytic progenitors and boosts apoptosis by inhibiting the production of PDGF and related signaling pathways. It is strongly advised that patients must be made more aware of the risks associated with using such over-the-counter medications.

Antiangiogenic, Anti-Inflammatory and Antioxidant Properties of Bidens tripartite Herb, Galium verum Herb and Rumex hydrolapathum Root.

Plants are commonly used in folk medicine. Research indicates that the mechanisms of biological activity of plant extracts may be essential in the treatment of various diseases. In this respect, we decided to test the ethanolic extracts of Bidens tripartita herb (BTH), Galium verum herb (GVH), and Rumicis hydrolapathum root (RHR) on angiogenic, anti-inflammatory, and antioxidant properties and their total polyphenols content. In vitro studies using endothelial cells were used to see tested extracts' angiogenic/angiostatic and anti-inflammatory properties. The DPPH assay and FRAP analysis were used to detect antioxidant properties of extracts. The Folin-Ciocalteu analysis was used to determine the content of total polyphenols. The results of gas chromatography-mass spectrometry analysis was also presented. In vitro study demonstrated that BTH, GVH, and RHR ethanolic extracts significantly increased cell invasiveness, compared with the control group. Increased endothelial proangiogenic invasiveness was accompanied by reduced metalloproteinase inhibitor 1 (TIMP-1) and raised in metalloproteinase 9 (MMP-9). Only BTH and GVH significantly reduced cell proliferation, while BTH and RHR facilitated migration. Additionally, tested extracts reduced the production of proangiogenic platelet-derived growth factor (PDGF) and hepatocyte growth factor (HGF). The most potent anti-inflammatory capacity showed BTH and GVH, reducing proinflammatory interleukin 8 (CXCL8) and interleukin 6 (Il-6), compared to RHR extract that has slightly less inhibited CXCL8 production without affecting IL-6 production. Moreover, we confirmed the antioxidant properties of all examined extracts. The highest activity was characterized by RHR, which has been correlated with the high content of polyphenols. In conclusion, the modifying influence of examined extracts can be promising in disorders with pathogenesis related to angiogenesis, inflammation and free radicals formation. BTH is the best choice among the three tested extracts with its antiangiogenic and anti-inflammatory properties.

Hepatoprotective activity of Averrhoa bilimbi L. fruit extract on carbon tetrachloride-induced acute liver faiure in Wistar rats

Background Acute liver failure (ALF) is a state of rapid and progressive deterioration of liver function. Continuous exposure to chemicals and viruses can increase reactive oxygen species (ROS) which leads to prolonged inflammation due to the production of tumor necrosis factor-alpha (TNF-á) thus inhibiting the production of platelet-derived growth factor (PDGF). The objective of this study was to evaluate the effect of administration of Averrhoa bilimbi L. fruit extract on PDGF levels and TNF-á levels in carbon tetrachloride (CCl4)-induced ALF rats. MethodsThis study used a post-test-only control group design involving 20 Wistar rats. They were randomized into 4 groups, namely sham, control, T1, and T2. Group T1 was exposed to CCl4 with the administration of A. bilimbi fruit extract at a dose of 500mg/kgBW, while, group T2 was exposed to CCl4 and given A. bilimbi fruit extract of 750 mg/kgBW. On the 15th day, the serum was analyzed to determine the levels of PDGF and TNF-á using ELISA. ResultsThe highest mean PDGF level in the control group was 146.60±15.36 pg/mL, while the highest mean TNF-á level in group T1 was 40.11±4.44 pg/mL. The One-way ANOVA test showed that there were significant differences in TNF-á (p=0.002) and PDGF (p=0.000) levels between the study groups. ConclusionThe administration of A.bilimbi L. fruit extract affected PDGF and TNF-á levels in CCl4-induced ALF rats. The present study revealed that A. bilimbi fruits have significant hepatoprotective activity in experimental Wistar rats.

Spindle pole body component 25 and platelet-derived growth factor mediate crosstalk between tumor-associated macrophages and prostate cancer cells.

Tumor-associated macrophages (TAMs) are involved in the growth of prostate cancer (PrC), while the molecular mechanisms underlying the interactive crosstalk between TAM and PrC cells remain largely unknown. Platelet-derived growth factor (PDGF) is known to promote mesenchymal stromal cell chemotaxis to the tumor microenvironment. Recently, activation of spindle pole body component 25 (SPC25) has been shown to promote PrC cell proliferation and is associated with PrC stemness. Here, the relationship between SPC25 and PDGF in the crosstalk between TAM and PrC was investigated. Significant increases in both PDGF and SPC25 levels were detected in PrC specimens compared to paired adjacent normal prostate tissues. A significant correlation was detected between PDGF and SPC25 levels in PrC specimens and cell lines. SPC25 increased PDGF production and tumor cell growth in cultured PrC cells and in xenotransplantation. Mechanistically, SPC25 appeared to activate PDGF in PrC likely through Early Growth Response 1 (Egr1), while the secreted PDGF signaled to TAM through PDGFR on macrophages and polarized macrophages, which, in turn, induced the growth of PrC cells likely through their production and secretion of transforming growth factor β1 (TGFβ1). Thus, our data suggest that SPC25 triggers the crosstalk between TAM and PrC cells via SPC25/PDGF/PDGFR/TGFβ1 receptor signaling to enhance PrC growth.

Mechanism Analysis of Antiangiogenic d-Isofloridoside from Marine Edible Red algae Laurencia undulata in HUVEC and HT1080 cell.

Laurencia undulata, as one of the most biologically active species in the genus Laurencia, is an edible folk herb red algae. Among them, d-isofloridoside (DIF, 940.68 Da) is isolated from Laurencia undulata, which has antioxidant and matrix metalloproteinases (MMP) inhibitory activities. However, its mechanism of action on tumor angiogenesis has not yet been reported. In this study, we have studied the mechanism of DIF on tumor metastasis and angiogenesis in HT1080 cell and human vascular endothelial cell (HUVEC). The results show that DIF can reduce the activity of MMP-2/9, and can inhibit the expression of hypoxia-inducible factor-1α (HIF-1α) by regulating the downstream PI3K/AKT and mitogen-activated protein kinases (MAPK) pathways, thereby down-regulating the production of vascular endothelial growth factor (VEGF) in CoCl2-induced HT1080 cell. In addition, DIF can inhibit the activation of VEGF receptor (VEGFR-2), regulate downstream PI3K/AKT, MAPK, nuclear factor-kappa B (NF-κB) signal pathways, activate apoptosis, and thus down-regulate the production of platelet-derived growth factor (PDGF) in VEGF-induced HUVEC. In conclusion, our research shows that DIF has the potential to develop into a tumor-preventing functional food and tumor angiogenesis inhibitor, and it can provide theoretical guidance for the high-value comprehensive utilization of edible red algae Laurencia undulata.

Isocorydine inhibits the proliferation of human endometrial carcinoma HEC-1B cells by downregulating the Ras/MEK/ERK signaling pathway

Objective: Isocorydine (ICD), an aporphine alkaloid, plays a role in anticancer activity that is still being evaluated. However, the exact function and mechanism of ICD in endometrial carcinoma is largely unknown. Methods: MTT, flow cytometry, western blot, immunofluorescence, RT-PCR and ELISA were used in this research. Results: In our study we showed that ICD inhibited endometrial carcinoma HEC-1B cell proliferation at certain times and concentrations. Simultaneously, ICD induced HEC-1B cells apoptosis. Further investigation indicated that ICD reduced the phosphorylation protein levels of c-Raf (rapidly accelerated fibrosarcoma), MEK1/2 (MAPK/Erk kinase) and ERK1/2 (extracellular regulated protein kinase). Moreover, a cell immunofluorescence assay confirmed that ICD reduced intracellular expression of Ras and then promoted FOXO3 (forkhead box O3) nuclear localization to furtherly increase the mRNA level of Bim and p27Kip1. Additionally, an enzyme-linked immunosorbent assay (ELISA) revealed that ICD inhibited the production of EGF (epidermal growth factor) and PDGF (Platelet-Derived Growth Factor), which indicated that ICD indirectly inhibited the activation of the Ras/MEK/ERK signaling pathway at the ligand level. Conclusion: Taken together, these data suggest for the first time that ICD inhibits cell proliferation and induces cell apoptosis in endometrial carcinoma through suppressing Ras/MEK/ERK signaling, which may provide a theoretical foundation to the application of ICD for the treatment of human endometrial carcinoma.

Endothelial platelet-derived growth factor-mediated activation of smooth muscle platelet-derived growth factor receptors in pulmonary arterial hypertension.

Platelet-derived growth factor is one of the major growth factors found in human and mammalian serum and tissues. Abnormal activation of platelet-derived growth factor signaling pathway through platelet-derived growth factor receptors may contribute to the development and progression of pulmonary vascular remodeling and obliterative vascular lesions in patients with pulmonary arterial hypertension. In this study, we examined the expression of platelet-derived growth factor receptor isoforms in pulmonary arterial smooth muscle and pulmonary arterial endothelial cells and investigated whether platelet-derived growth factor secreted from pulmonary arterial smooth muscle cell or pulmonary arterial endothelial cell promotes pulmonary arterial smooth muscle cell proliferation. Our results showed that the protein expression of platelet-derived growth factor receptor α and platelet-derived growth factor receptor β in pulmonary arterial smooth muscle cell was upregulated in patients with idiopathic pulmonary arterial hypertension compared to normal subjects. Platelet-derived growth factor activated platelet-derived growth factor receptor α and platelet-derived growth factor receptor β in pulmonary arterial smooth muscle cell, as determined by phosphorylation of platelet-derived growth factor receptor α and platelet-derived growth factor receptor β. The platelet-derived growth factor-mediated activation of platelet-derived growth factor receptor α/platelet-derived growth factor receptor β was enhanced in idiopathic pulmonary arterial hypertension-pulmonary arterial smooth muscle cell compared to normal cells. Expression level of platelet-derived growth factor-AA and platelet-derived growth factor-BB was greater in the conditioned media collected from idiopathic pulmonary arterial hypertension-pulmonary arterial endothelial cell than from normal pulmonary arterial endothelial cell. Furthermore, incubation of idiopathic pulmonary arterial hypertension-pulmonary arterial smooth muscle cell with conditioned culture media from normal pulmonary arterial endothelial cell induced more platelet-derived growth factor receptor α activation than in normal pulmonary arterial smooth muscle cell. Accordingly, the conditioned media from idiopathic pulmonary arterial hypertension-pulmonary arterial endothelial cell resulted in more pulmonary arterial smooth muscle cell proliferation than the media from normal pulmonary arterial endothelial cell. These data indicate that (a) the expression and activity of platelet-derived growth factor receptor are increased in idiopathic pulmonary arterial hypertension-pulmonary arterial smooth muscle cell compared to normal pulmonary arterial smooth muscle cell, and (b) pulmonary arterial endothelial cell from idiopathic pulmonary arterial hypertension patients secretes higher level of platelet-derived growth factor than pulmonary arterial endothelial cell from normal subjects. The enhanced secretion (and production) of platelet-derived growth factor from idiopathic pulmonary arterial hypertension-pulmonary arterial endothelial cell and upregulated platelet-derived growth factor receptor expression (and function) in idiopathic pulmonary arterial hypertension-pulmonary arterial smooth muscle cell may contribute to enhancing platelet-derived growth factor/platelet-derived growth factor receptor-associated pulmonary vascular remodeling in pulmonary arterial hypertension.

Daily high-dose aspirin does not lower APRI in the Aspirin-Myocardial Infarction Study.

Antiplatelet agents reduce liver fibrosis by inhibiting platelet activation and platelet-derived growth factor production. Previous cross-sectional epidemiological studies suggest that the use of aspirin is related to reduced liver fibrosis. The Aspirin-Myocardial Infarction Study (AMIS) aims to examine this relationship in a multicenter, randomized, double-blind and placebo-controlled trial. The existing clinical trial of aspirin was conducted to study the benefit of one gram aspirin daily among 4 524 individuals who had experienced at least one documented myocardial infarction. The aspartate aminotransferase (AST)-to-Platelet Ratio Index (APRI) was calculated at baseline and annually from the platelet count and AST levels. Participants in the AMIS trial had a mean baseline APRI of 0.34±0.36, and only 1% individuals had APRI scores higher than 1.0, a common cutoff for cirrhosis. The daily use of aspirin was associated with an increase, rather than a reduction of APRI, by 0.007 per year (95% CI 0.002-0.015, P=0.12). The use of aspirin did not significantly affect platelet counts. In a sensitivity analysis of individuals with probable significant fibrosis at baseline (APRI≥0.7), the aspirin group had a sustained reduction in APRI over time, although this change was not significant compared to that in the placebo group. In the AMIS trial, the daily use of high-dose aspirin did not significantly affect APRI, a surrogate index of liver fibrosis. This study highlights the need for de novo clinical trials to investigate the potential benefit of antiplatelet agents on liver fibrosis.

The comparison of fibroblast count and collagen density score in ileal anastomosis with continuous and interrupted suture technique on New Zealand Rabbit

Introduction: Intestinal anastomosis is carried out with the continuous and simple interrupted sutures technique. Simple interrupted suture is the standard technique in intestinal anastomosis nowadays1,2. Continuous suture has better serosal apposition, shorter processing time and triggers the formation of hypoxia-inducible factor (HIF) which can stimulate the production of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) that stimulate migration and proliferation of mesenchymal cells, especially fibroblast cells which support the synthesis and increasing collagen density in anastomosis tissue. The aim of current study is to compare the anastomosis technique with continuous and simple interrupted sutures reviewed from fibroblast count and collagen density score in rabbit intestines.Method: This study is an experimental study. The sample of this study consisted of 36 rabbits divided into two groups continuous and simple interrupted sutures. Randomization is done by permuted randomization block. The inclusion criteria in this study were rabbit strain Oryctolagus cuniculus aged 8-9 months, weighted 2000-2500 grams, healthy and active. The independent variable in this study is the ileal anastomosis technique and the dependent variable is the fibroblasts count and the collagen density score formed on the anastomosis tissue assessed histopathologically.Results: This study found the average age of the rabbit was 8 months, with an average weight of 2400 grams, the number of fibroblasts in the group of rabbits which received continuous suture was 47 ± 12.679 fibroblasts per visual field with collagen score was 1.88 ± 0.781, whereas in rabbits with interrupted sutures, the fibroblasts count was 42.76 ± 12.47 fibroblasts per visual field with collagen score was 1.82 ± 0.728. However, from the analytic testing showed that the rabbits treated with continuous suture were not significantly different in fibroblast count and collagen density score compared to simple interrupted group (p>0.05), but in continuous rabbit group have higher collagen density scores and fibroblasts count than rabbits who get simple interrupted sutureConclusion: This study proves that continuous suture results in higher fibroblast count and collagen density score than interrupted suture yet statistically insignificant.

Human Bone Marrow-Derived Mesenchymal Stem Cells Home via the PI3K-Akt, MAPK, and Jak/Stat Signaling Pathways in Response to Platelet-Derived Growth Factor.

Mesenchymal stem cells (MSCs) have great potential to improve clinical outcomes for many inflammatory and degenerative diseases either through intravenously delivered MSCs or through mobilization and migration of endogenous MSCs to injury sites, termed "stem cell homing." Stem cell homing involves the processes of attachment to and transmigration through endothelial cells lining the vasculature and migration through the tissue stroma to a site of injury or inflammation. Although the process of leukocyte transendothelial migration (TEM) is well understood, far less is known about stem cell homing. In this study, a transwell-based model was developed to monitor adherence and TEM of human MSCs in response to chemokine exposure. Specifically, transwell membranes lined with human synovial microvascular endothelial cells were partitioned from the tissue injury-mimetic site containing chemokine stromal cell-derived factor-1 (SDF-1). Two population subsets of MSCs were studied: migratory cells that initiated transmigration on the endothelial lining and nonmigratory cells. We hypothesized that cells would adhere to and migrate through the endothelial lining in response to SDF-1 exposure and that gene and protein expression changes would be observed between migratory and nonmigratory cells. We validated a vasculature model for MSC transmigration that showed increased expression of several genes and activation of proteins of the PI3K-Akt, MAPK, and Jak/Stat signaling pathways. These findings showed that MSC homing may be driven by activation of PDGFRA/PI3K/Akt, PDGFRA/MAPK/Grb2, and PDGFRA/Jak2/Stat signaling, as a result of SDF-1-stimulated endothelial cell production of platelet-derived growth factor. This model can be used to further investigate these key regulatory molecules toward the development of targeted therapies.

Autocrine Production of PDGF Stimulated by the Tenascin-C-Derived Peptide TNIIIA2 Induces Hyper-Proliferation in Glioblastoma Cells.

Expression level of tenascin-C is closely correlated to poor prognosis in glioblastoma patients, while the substantial role of tenascin-C responsible for aggressive progression in glioblastoma cells has not been clarified. We previously found that peptide TNIIIA2, which is derived from the tumor-associated tenascin-C variants, has the ability to promote cell adhesion by activating β1-integrins. Our recent study demonstrated that potentiated activation of integrin α5β1 by TNIIIA2 causes not only a dysregulated proliferation in a platelet-derived growth factor (PDGF)-dependent manner, but also disseminative migration in glioblastoma cells. Here, we show that TNIIIA2 enhances the proliferation in glioblastoma cells expressing PDGF-receptorβ, even without exogenous PDGF. Mechanistically, TNIIIA2 induced upregulated expression of PDGF, which in turn stimulated the expression of tenascin-C, a parental molecule of TNIIIA2. Moreover, in glioblastoma cells and rat brain-derived fibroblasts, tenascin-C upregulated matrix metalloproteinase-2, which has the potential to release TNIIIA2 from tenascin-C. Thus, it was shown that autocrine production of PDGF triggered by TNIIIA2 functions to continuously generate a functional amount of PDGF through a positive spiral loop, which might contribute to hyper-proliferation in glioblastoma cells. TNIIIA2 also enhanced in vitro disseminative migration of glioblastoma cells via the PKCα signaling. Collectively, the tenascin-C/TNIIIA2 could be a potential therapeutic target for glioblastoma.

Bromodomain inhibition instructs macrophages to promote beta cell proliferation and suppress autoimmune diabetes

Abstract A hallmark of autoimmune type 1 diabetes (T1D) is the decline of beta cell mass. Any regimen to promote beta cell expansion will have a great therapeutic promise. We have previously demonstrated that an epigenetic inhibitor targeting BET proteins (I-BET) promotes beta cell proliferation in an animal model of T1D. However, the underlying mechanisms remains unknown. Using both gain-of and loss-of function assays, we demonstrate that macrophages play an indispensable role in I-BET-elicited beta cell proliferation. In vivo ablation of macrophages significantly abolishes, while the supplementation of I-BET preconditioned macrophages enhances, I-BET induced beta cell proliferation. On a molecular level, elevated production of platelet-derived growth factor (PDGF) in I-BET treated macrophages mobilizes PDGFR signaling in beta cells. In summary, these findings reveal a novel strategy to expand beta cells by harnessing macrophages.

β-catenin-activated autocrine PDGF/Src signaling is a therapeutic target in pancreatic cancer.

K-ras mutation and p53 loss are the most prevalent genetic alterations in pancreatic cancer. In addition to these two alterations, pancreatic tumors frequently contain a third genetic defect. Mutations in the WNT/ß-catenin signaling molecules occur in 15-20% of pancreatic cancer patients and co-exist with K-ras mutation and p53 loss. However, the contribution of the WNT/ß-catenin pathway in pancreatic tumorigenesis is still unclear.Methods: We generated Pdx1-CreKrasG12Dp53L/+APCL/+ (KPA) mice and compared their phenotypes with Pdx1-CreKrasG12Dp53L/+ (KPC) mice. The signaling pathways specifically activated in the KPA mice were investigated and the therapeutic effect by targeting the activated pathways was evaluated. We finally validated our findings in human blood and tumor samples.Results: Survival of the KPA mice was shorter than that of the KPC mice. The KPA cancer cells are highly invasive and exhibit distorted morphology in organoid culture with extensive invadopodia formation and elevated matrix metalloproteinase (MMP) activity. The platelet-derived growth factor (PDGF) pathway is upregulated in the KPA cancer cells, and PDGF production induced by ß-catenin triggers constitutive activation of the Src kinase via the PDGF receptor in the cells. Serum PDGF concentration of the KPA mice is much higher than that of the normal and KPC mice. The Src inhibitor dasatinib effectively inhibits tumor growth and metastasis of the KPA cancer cells. Patient's serum PDGF level is significantly correlated with the expression of PDGF and phosphor-Src in tumors and elevated PDGF/phosphor-Src level in tumors predicts increased recurrence and poor survival. Moreover, mutations of the WNT/ß-catenin signaling molecules are higher in patients with elevated PDGF/phosphor-Src level.Conclusion: ß-catenin activation, coupled with K-ras mutation and p53 loss, activates an autocrine PDGF/Src signaling in pancreatic cancer and defines a subset of patients who might be sensitive to Src inhibition. In addition, serum PDGF level could be a reliable biomarker for patient selection in clinic.

Effect of Topical Opioid Antagonist on Diabetic Wound Healing in Rat Model

Category: Basic Sciences/Biologics, Diabetes Introduction/Purpose: Approximately 50% of the 170 million people worldwide with diabetes experience complications associated with delayed cutaneous wound healing. The current widely used treatment for DFU is topical platelet-derived growth factor (PDGF); however, it has significant side-effects. Preclinical studies have shown that a small molecular weight opioid receptor antagonist, blocks the interactions between the growth inhibitory peptide Opioid Growth Factor (OGF) and its receptor OGFr and accelerates cell proliferation and enhances angiogenesis and wound closure. The hypothesis of this research is that the topical formulation of opioid receptor antagonist is an effective therapy for healing of cutaneous wounds in diabetic rats, with healing times comparable to the standard care and will promote enhanced cell replication and accelerated angiogenesis. Methods: Fourteen diabetic rats per group with four excisional cutaneous wounds were positioned dorsally on type 1 diabetic rats and randomly treated topically with an opioid receptor antagonist (0.03% Naltrexone), topical platelet derived growth factor (Regranex®), or placebo moisturizing cream alone. Wound closure, DNA synthesis (bromodeoxyuridine incorporation-BrdU labeling), and production of the cytokines PDGF and vascular endothelial growth factor (VEGF) were monitored. Results: Naltrexone and Regranex® treatment resulted in more than 65% closure on days 8 and 10 respectively. On day 12, only one Naltrexone- and two Regranex-treated wounds remained (~1%), whereas the control group had 50% visible wounds. DNA synthesis in Regranex® treated wounds was 21% in comparison to vehicle-treated wounds at 28%; Naltrexone-treated diabetic wounds had 42% BrdU labeling comparable to the normal vehicle treated wounds. Naltrexone treatment significantly increased cell replication in comparison to Regranex treatment and to vehicle-only treated wounds (p<0.001). Tissue immunostained at 1, 2, and 4 days after surgery with anti-PDGF antibodies indicated that both Regranex® and Naltrexone increase PDGF+ labeling at 1 day, with Naltrexone treatment (but not Regranex®) continuing to enhance PDGF production at 4 days Conclusion: Topical opioid receptor antagonist has been shown to enhance wound healing by increasing cell replication, accelerating angiogenesis, and matrix formation and targets an underlying pathophysiology of diabetes and enhances cell replication at all stages of wound remodeling. Topical opioid receptor antagonist is safe and effectively targets the disease-modifying pathways in this comparison study of topical platelet derived growth factor for wound closure in Type 1 diabetic rats.These data suggest that blockade of the OGF-OGFr axis, utilizing 0.03% Naltrexone is a safe and effective alternative for treatment for diabetic wounds by targeting several phases of wound repair.

Insulin-like growth factor-binding protein-3 inhibits IGF-1-induced proliferation of human hepatocellular carcinoma cells by controlling bFGF and PDGF autocrine/paracrine loops

Basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) produced by hepatocellular carcinoma (HCC) cells are responsible for the growth of HCC cells. Accumulating evidence shows that insulin-like growth factor-binding protein-3 (IGFBP-3) suppresses HCC cell proliferation in both IGF-dependent and independent manners. It's unknown, however, whether treatment with exogenous IGFBP-3 inhibits bFGF and PDGF production in HCC cells. The present study demonstrates that IGFBP-3 suppressed IGF-1-induced bFGF and PDGF expression while it does not affect their expression in the absence of IGF-1. To delineate the underlying mechanism, western-blot and RT-PCR assays confirmed that the transcription factor early growth response protein 1 (EGR1) is involved in IGFBP-3 regulation of bFGF and PDGF. IGFBP-3 inhibition of type 1 insulin-like growth factor receptor (IGF1R), ERK and AKT activation is IGF-1-dependent. Furthermore, transient transfection with constitutively activated AKT or MEK partially blocks the IGFBP-3 inhibition of EGR1, bFGF and PDGF expression. In conclusion, these findings suggest that IGFBP-3 suppresses transcription of EGR1 and its target genes bFGF and PDGF through inhibiting IGF-1-dependent ERK and AKT activation. It demonstrates the importance of IGFBP-3 in the regulation of HCC cell proliferation, suggesting that IGFBP-3 could be a target for the treatment of HCC.

Growth factors and experimental arterial grafts

The production of growth factors from several experimental arterial conduits was determined. We implanted 105 experimental arterial grafts that were 1cm long in the abdominal aorta of Lewis rats (average weight, 250g). Five different types of grafts were analyzed: arterial isografts, vein grafts, arterial allografts, and polytetrafluoroethylene (PTFE) grafts with normal or decreased compliance. Animals were killed humanely 4weeks after surgery and the production of platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), transforming growth factor-β, tumor necrosis factor-α, and interleukin-1 was analyzed. Myointimal hyperplasia (MH) was evident in vein grafts, arterial allografts, and PTFE grafts, but not in arterial isografts. Growth factor production was increased for grafts prone to develop MH like vein, PTFE grafts, and arterial allografts. PDGF and bFGF were increased significantly for PTFE and vein grafts, but not for arterial allografts. The importance of bFGF and PGDF was confirmed by the capability of antibody to PDGF and to bFGF to reduce the mitogenic activity of smooth muscle cells, invivo and invitro, for PTFE and vein grafts, but not for arterial allografts, in which a predominant role was played by interleukin-1 and tumor necrosis factor-α. Agents able to neutralize this increased production of growth factors, either directly or by competition with their receptors, can prevent MH formation.

Aortic smooth muscle cell alterations in mice systemically exposed to arsenic.

Previous epidemiological studies showed that chronic arsenic exposure is related to increased cardiovascular disease incidence. The detailed biochemical mechanisms by which arsenic exerts its effects remain unknown. Vascular disease progression is characterized by smooth muscle cell (SMC) phenotypic switching, vessel wall reorganization, and platelet-derived growth factor (PDGF) production. The objective of this study was to examine early biochemical and structural changes in the aortas of ICR mice systemically exposed to arsenic. Animals were fed sodium arsenite (20mg/kg) via gavage 5days/week or Milli-Q water only (control) for 8weeks. Aortic proteins were subjected to two-dimensional (2-D) differential gel electrophoresis and proteomic studies. Two 2-D gel protein spots were identified as the same protein, smooth muscle (SM)22α, using proteomics. SM22α and Rho kinase 2 gene and protein expression were significantly decreased in the aortic tissue of arsenic-exposed mice compared with that of control mice. No atherosclerotic lesion formation or tissue injury was detected in the aortic wall of either the arsenic-fed or the control group. However, the percent (%) SMC area of the aortic wall was significantly decreased in arsenic-fed mice compared with that in control mice. Additionally, the expression levels of PDGF-BB and early growth response-1 (Egr-1) were significantly higher in the arsenic group than that in the control group. These findings reveal biochemical alterations of SM22α, PDGF, and Egr-1 in conjunction with decreased SMC area in the aortic wall of arsenic-fed mice. Arsenic may initiate aortic SMC alterations that subsequently lead to vascular dysfunction.

Monocyte interaction accelerates HCl-induced lung epithelial remodeling.

BackgroundAcute respiratory distress syndrome (ARDS) is characterized by overwhelming inflammatory responses and lung remodeling. We hypothesized that leukocyte infiltration during the inflammatory response modulates epithelial remodeling through a mechanism of epithelial-mesenchymal transition (EMT).MethodsHuman lung epithelial cells were treated for 30 min with hydrochloric acid (HCl). Human monocytes were then cocultured with the epithelial cells for up to 48 h, in the presence or absence of blocking peptides against lymphocyte function-associated antigen-1 (LFA-1), or tyrphostin A9, a specific inhibitor for platelet-derived growth factor (PDGF) receptor tyrosine kinase.ResultsExposure of lung epithelial cells to HCl resulted in increased expression of intercellular adhesion molecule-1 (ICAM-1) and production of interleukin (IL)-8 at 24 h. The expression of the epithelial markers E-cadherin decreased while the mesenchymal markers vimentin and α-smooth muscle actin (α-SMA) increased at 24 h and remained high at 48 h. The addition of monocytes augmented the profiles of lower expression of epithelial markers and higher mesenchymal markers accompanied by increased collagen deposition. This EMT profile was associated with an enhanced production of IL-8 and PDGF. Treatment of the lung epithelial cells with the LAF-1 blocking peptides CD11a237–246 or/and CD18112–122 suppressed monocyte adhesion, production of IL-8, PDGF and hydroxyproline as well as EMT markers. Treatment with tyrphostin A9 prevented the EMT profile shift induced by HCl stimulation.ConclusionsThe interaction between epithelial cells and monocytes enhanced epithelial remodelling after initial injury through EMT signalling that is associated with the release of soluble mediators, including IL-8 and PDGF.

The delayed addition of human mesenchymal stem cells to pre-formed endothelial cell networks results in functional vascularization of a collagen–glycosaminoglycan scaffold in vivo

This paper demonstrates a method to engineer, in vitro, a nascent microvasculature within a collagen–glycosaminoglycan scaffold with a view to overcoming the major issue of graft failure due to avascular necrosis of tissue-engineered constructs. Human umbilical vein endothelial cells (ECs) were cultured alone and in various co-culture combinations with human mesenchymal stem cells (MSCs) to determine their vasculogenic abilities in vitro. Results demonstrated that the delayed addition of MSCs to pre-formed EC networks, whereby MSCs act as pericytes to the nascent vessels, resulted in the best developed vasculature. The results also demonstrate that the crosstalk between ECs and MSCs during microvessel formation occurs in a highly regulated, spatio-temporal fashion, whereby the initial seeding of ECs results in platelet derived growth factor (PDGF) release; the subsequent addition of MSCs 3days later leads to a cessation in PDGF production, coinciding with increased vascular endothelial cell growth factor expression and enhanced vessel formation. Functional assessment of these pre-engineered constructs in a subcutaneous rat implant model demonstrated anastomosis between the in vitro engineered vessels and the host vasculature, with significantly increased vascularization occurring in the co-culture group. This study has thus provided new information on the process of in vitro vasculogenesis within a three-dimensional porous scaffold for tissue engineering and demonstrates the potential for using these vascularized scaffolds in the repair of critical sized bone defects.

Angioimmunoblastic T-cell lymphoma with intramedullary production of platelet-derived growth factor and possibly complicating myelofibrosis: report of a case with review of the literature

A 65-year-old man was diagnosed with angioimmunoblastic T-cell lymphoma (AITL) with bone marrow (BM) infiltration and myelofibrosis (MF). The BM infiltration and the condition of the MF improved following CHOP therapy (cyclophosphamide hydrate, doxorubicin hydrochloride, vincristine sulfate, and prednisolone). After complete remission was achieved, early central nervous system recurrence was noted, with no evidence of BM infiltration or MF. The lymph nodes and BM were examined for cytokines by immunohistochemical staining with monoclonal murine antibodies. The lymphoma cells were positive only for platelet-derived growth factor (PDGF) and negative for basic fibroblast growth factor, fibronectin, vascular endothelial growth factor, transforming growth factor-β (TGF-β), tumor necrosis factor α, interleukin-1β, and interleukin-6. It was thus inferred that the lymphoma cells producing PDGF caused the MF, and that the absence of MF at relapse may have been attributable to the absence of BM infiltration. There have been seven reported cases of AITL with intercurrent MF, although cytokine data (elevations of blood PDGF and TGFβ levels) are available for only one case. The present report is to our knowledge the only report of a case of AITL complicated by MF for which the results of immunohistostaining with anticytokine antibodies are available.