Concentrations Of PDGF-AB Research Articles

Effect of Mechanical Stimulation Combined With Platelet-Rich Plasma on Healing of the Rotator Cuff in a Murine Model

Background: Mechanical stimulation and platelet-rich plasma (PRP) have been shown to be beneficial for healing of the bone-tendon interface (BTI), but few studies have explored the efficacy of a combination of these applications. We investigated the effect of mechanical stimulation combined with PRP on rotator cuff repair in mice. Hypothesis: Mechanical stimulation combined with PRP can enhance BTI healing in a murine model of rotator cuff repair. Study Design: Controlled laboratory study. Methods: A total of 160 C57BL/6 mice were used. Overall, 40 mice were used to prepare PRP, while 120 mice underwent acute supraspinatus tendon (SST) repair. The animals were randomly assigned to 4 groups: control group, mechanical stimulation group, PRP group, and mechanical stimulation combined with PRP group (combination group). At 4 and 8 weeks postoperatively, animals were sacrificed, the eyeballs were removed to collect blood, and the SST–humeral complexes were collected. Histological, biomechanical, immunological, and bone morphometric tests were performed. Results: Histologically, at 4 and 8 weeks after surgery, the area of the fibrocartilage layer at the BTI in the combination group was larger than in the other groups. The content and distribution of proteoglycans in this layer in the combination group were significantly greater than in the other groups. At 8 weeks postoperatively, trabecular number, and trabecular bone thickness of the subchondral bone area of interest at the BTI of the combination group were greater than those of the other groups, bone volume fraction of the combination group was greater than the control group. On biomechanical testing at 4 and 8 weeks after surgery, the failure load and ultimate strength of the SST–humeral complex in the combination group were higher than in the other groups. Enzyme-linked immunosorbent assay results showed that, at 4 weeks postoperatively, the serum concentrations of transforming growth factor beta 1 and platelet-derived growth factor (PDGF) in the combination group were significantly higher than in the other groups; at 8 weeks, the PDGF-AB concentration in the combination group was higher than in the control and mechanical stimulation groups. Conclusion: Mechanical stimulation combined with PRP can effectively promote the early stage of healing after a rotator cuff injury. Clinical Relevance: These findings imply that mechanical stimulation combined with PRP can serve as a potential therapeutic strategy for rotator cuff healing.

Why PRP works only on certain patients with tennis elbow? Is PDGFB gene a key for PRP therapy effectiveness? A prospective cohort study

BackgroundThere is variability in individual response to platelet-rich plasma (PRP) therapy in tennis elbow treatment. Genetic variation, especially within genes encoding growth factors may influence the observed inter-individual differences. The purpose of this study was to identify polymorphic variants of the platelet-derived growth factor beta polypeptide gene (PDGFB) that determine an improved individual response to PRP therapy in tennis elbow patients.MethodsThis prospective cohort study was designed in accordance with STROBE and MIBO guidelines. A cohort of 107 patients (132 elbows, 25 bilateral) was studied, including 65 females (77 elbows) and 42 males (55 elbows), aged 24–64 years (median 46.00 ± 5.50), with lateral elbow tendinopathy treated with autologous PRP injection. The effectiveness of PRP therapy was recorded in all subjects at 2, 4, 8, 12, 24 and 52 weeks after PRP injection using the Visual Analog Scale (VAS), quick version of Disabilities of the Arm, Shoulder and Hand score (QDASH) and Patient-Rated Tennis Elbow Evaluation (PRTEE). In order to determine the PDGFB variants with the best response to PRP therapy, patient reported outcome measures were compared between individual genotypes within studied polymorphic variants (rs2285099, rs2285097, rs2247128, rs5757572, rs1800817 and rs7289325). The influence of single nucleotide polymorphisms on blood and PRP parameters, including the concentration of PDGF-AB and PDGF-BB proteins was also analyzed.ResultsOur analysis identified genetic variants of the PDGFB gene that lead to a better response to PRP therapy. The TT (rs2285099) and CC (rs2285097) homozygotes had higher concentration of platelets in whole blood than carriers of other genotypes (p = 0.018) and showed significantly (p < 0.05) lower values of VAS (weeks 2–12), QDASH and PRTEE (weeks 2–24). The rs2285099 and rs2285097 variants formed strong haplotype block (r2 = 98, D’=100). The AA homozygotes (rs2247128) had significantly lower values of VAS (weeks 4–52), QDASH and PRTEE (weeks 8, 12).ConclusionsPDGFB gene’s polymorphisms increase the effectiveness of PRP therapy in tennis elbow treatment. Genotyping two polymorphisms of the PDGFB gene, namely rs2285099 (or rs2285097) and rs2247128 may be a helpful diagnostic tool while assessing patients for PRP therapy and modifying the therapy to improve its effectiveness.

Vitreous and Serum Concentrations of Vascular Endothelial Growth Factor and Platelet-Derived Growth Factor in Proliferative Diabetic Retinopathy.

PurposeThis study aimed to investigate the concentrations of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) in vitreous and serum samples, analyze the ratio, and compare among proliferative diabetic retinopathy (PDR) subgroups.Patients and MethodsThis study included 17 eyes of patients with PDR, identified as the PDR group which was divided into three subgroups (vitreous hemorrhage [VH], VH with fibrotic tissues, and tractional retinal detachment), and five control eyes (nucleus and intraocular lens drop). Vitreous and serum samples were obtained on the same day. The VEGF-A and PDGF-AB concentrations were calculated by enzyme-linked immunosorbent assay.ResultsThe VEGF-A and PDGF-AB concentrations in vitreous samples were significantly higher in the PDR group (630.72 ± 342.81 pg/mL) compared with those in the control group (153.58 ± 145.85 pg/mL); however, they were not detected in serum samples. The vitreous/serum ratio of the VEGF-A concentration in the PDR group (2.1 ± 1.8) was significantly higher compared with that in the control group (0.31 ± 0.33). The VEGF-A concentrations in vitreous samples were highest in the VH group and lowest in the VH with fibrotic tissue subgroup (mean difference 536.16 pg/mL). The vitreous VEGF-A/PDGF-AB concentration ratios were also significantly different among the PDR subgroups.ConclusionHigh concentrations of VEGF and PDGF in vitreous samples of PDR eyes indicate its local related activity in PDR pathology. There is a possibility of PDGF involvement in the pathogenesis of PDR. The VEGF/PDGF concentration ratios possibly play a significant role in the formation of fibrotic tissue in PDR.

PDGF-BB homodimer serum level - a good indicator of the severity of alcoholic liver cirrhosis.

Liver cirrhosis is a chronic disease in which progressive fibrosis is noted. This process leads to changed architectonics of the liver parenchyma and the appearance of regenerative nodules, all of which are caused by pathological activation of the hepatic stellate cells. This process is enhanced on a molecular level by many cytokines, with platelet-derived growth factors (PDGFs) playing the key role. The aim of the study was to assess serum concentrations of PDGFs active biodymers (PDGF-AA, PDGF-BB and PDGF-AB) in patients with alcoholic liver cirrhosis, and to correlate them with the stage of disease. 64 patients with alcoholic cirrhosis and a control group of 16 healthy individuals were analysed. Liver cirrhosis was determined based on clinical image, history of the patients' alcohol consumption, laboratory findings and abdominal ultrasonography. The serum PDGF-AA, PDGF-BB and PDGF-AB concentrations were determined using ELISA kits. Serum concentration of PDGF-AA and PDGF-BB homodimers increases in patients with alcoholic liver cirrhosis (p=0.034 and p<0.0001, respectively), unlike the serum concentration of PDGF-AB heterodimer (p>0.05). When the stage of the disease increases, the concentrations of PDGF-AA and PGFD-BB in blood also oncrease. Furthermore, the serum level of both PDGF-AA and PDGF-BB correlates significantly with the severity of alcoholic liver cirrhosis (measured by Pugh-Child's scale), the correlation being stronger in the case of PDGF-BB levels than PDGF-AA (R=0.28; p=0.027 and R=0.26; p=0.038, respectively). The plasma levels of PDGF-AA and -BB may be indicators of alcohol-induced liver fibrosis process, and might be considered as future possible treatment targets, with PDGF-BB levels being an even better indicator than PDGF-AA levels.

Platelet-rich plasma in lower limb ulcers

Objective The aim of this study was to evaluate the role of platelet-rich plasma gel in patient with lower limb ulcers: diabetic and varicose ulcers. Background Diabetic foot ulcer is a major complication of diabetes mellitus. Platelet-rich plasma (PRP) is used for managing diabetic foot ulcers. PRP contains alpha- granules that release growth factors on activation such as platelet-derived growth factor (PDGF) which are important for wound healing by being angiogenic and helping stem cell differentiation and maturation. Patients and methods The study included 30 patients with chronic ulcers who were selected from vascular surgery department of Menoufia University Hospitals in the duration between February 2016 and March 2017. Patients were categorized into group I (15 patients with diabetic ulcers) and group II (15 patients with varicose ulcers). PRP gel was applied every 2 weeks for a maximum of 6 weeks. PRP was evaluated for concentration of PDGF-AB before and after activation by immunoassay. Results There was significant increase in PRP platelets count and PDGF-AB concentration after activation (P Conclusion Autologous PRP gel is an efficient and a safe source of growth factors for managing lower limb ulcers.

The production method affects the efficacy of platelet derivatives to expand mesenchymal stromal cells in vitro

BackgroundThe use of fetal bovine serum (FBS) as a media supplement for the ex vivo expansion of bone-marrow derived mesenchymal stromal cells (BM-MSC) has been discouraged by regulatory agencies, due to the risk of transmitting zoonoses and to elicit immune reactions in the host once transplanted. Platelet derivatives are valid FBS substitutes due to their content of growth factors that can be released disrupting the platelets by physical methods or physiological stimuli. We compared platelet derivatives produced by freezing/thawing (platelet lysates, PL) or after CaCl2 activation (platelet releasate surnatant rich in growth factors, PR-SRGF) for their content in growth factors and their ability to support the ex vivo expansion of BM-MSC.MethodsThe cytokine content in the two platelet derivatives was evaluated. BM-MSC were expanded in complete medium containing 10, 7.5 and 5% PL or PR-SRGF and the cell phenotype, clonogenic capacity, immunomodulation properties and tri-lineage differentiation potential of the expanded cells in both media were investigated.ResultsThe concentration of PDGF-AB, PDGF-AA, PDGF-BB in PR-SRGF resulted to be respectively 5.7×, 1.7× and 2.3× higher compared to PL. PR-SRGF promoted a higher BM-MSC proliferation rate compared to PL not altering BM-MSC phenotype. Colony forming efficiency of BM-MSC expanded in PR-SRGF showed a frequency of colonies significantly higher than cells expanded in PL. BM-MSC expanded in PL or PR-SRGF maintained their immunomodulatory properties against activated lymphocytes even if BM-MSC expanded in FBS performed significantly better.ConclusionsThe method used to release platelet factors significantly affects the enrichment in growth factors and overall product performance. The standardization of the production process of platelet derivatives and the definition of their release criteria requires further investigation.

Quantification of TGF-ß1, PDGF and IGF-1 cytokine expression after fracture treatment vs. non-union therapy via masquelet

IntroductionBiochemical processes during bone regeneration can be analysed via quantification of peripheral serum cytokine levels. To date, serum levels of cytokines in patients treated with masquelet technique and patients with normal bone healing have not been compared. This comparison is supposed to deliver novel insights into the process of bone regeneration. Our aim was to validate this established method in the monitoring of bone regeneration after non-union treatment in masquelet technique. Materials and methodsBetween 04/2008 and 01/2014 three groups were recruited: G1 (10 patients) with long bone non-unions, treated successfully with masquelet therapy, G2 (6 patients) with unsuccessful masquelet therapy and G3 (10 patients) with long bone fractures and normal bone healing. Peripheral blood samples were collected over a period of six months following a standardised time pattern in combination with clinical and radiologic follow up. TGF-ß1, PDGF-AB and IGF-1 were measured using commercially available immunoassays. ResultsTGF-ß1 levels in G1 and G2 demonstrated a parallel and lower overall concentration over time compared to G3. G3 showed a significant TGF-ß1 peak 2 weeks after surgery compared to G1 (p=0.0054). PDGF-AB concentrations were always lower in G2 than in G1 and G3. G3 peaked at week 2 with a significant higher value than in G2 (p=0.0177). IGF-1 showed lower overall serum concentrations in G2 than in G1 and G3. G1 had a peak level during the fourth week of follow-up. Compared to G2 this peak was significant (p=0.0015). ConclusionsThis study shows that successful bone regeneration via masquelet technique only partially imitates cytokine expression of physiological bone healing. High expressions of IGF-1 correspond to a successful masquelet therapy while TGF-ß seems to play a minor role. These results assume that objective analysis of an effective non-union therapy with cytokine expression analysis is possible even with a small number of patients.

Effects of 2-year calorie restriction on circulating levels of IGF-1, IGF-binding proteins and cortisol in nonobese men and women: a randomized clinical trial.

Young-onset calorie restriction (CR) in rodents decreases serum IGF-1 concentration and increases serum corticosterone levels, which have been hypothesized to play major roles in mediating its anticancer and anti-aging effects. However, little is known on the effects of CR on the IGF-1 system and cortisol in humans. To test the sustained effects of CR on these key hormonal adaptations, we performed a multicenter randomized trial of a 2-year 25% CR intervention in 218 nonobese (body mass index between 22 and 27.8kgm(-2) ) young and middle-aged (20-50years age range) men and women. Average CR during the first 6months was 19.5±0.8% and 9.1±0.7% over the next 18months of the study. Weight loss averaged 7.6±0.3kg over the 2-years period of which 71% was fat mass loss (P<0.0001). Average CR during the CR caused a significant 21% increase in serum IGFBP-1 and a 42% reduction in IGF-1:IGFBP-1 ratio at 2years (P<0.008), but did not change IGF-1 and IGF-1:IGFBP-3 ratio levels. Serum cortisol concentrations were slightly but significantly increased by CR at 1year only (P=0.003). Calorie restriction had no effect on serum concentrations of PDGF-AB and TGFβ-1. We conclude, on the basis of the present and previous findings, that, in contrast to rodents, humans do not respond to CR with a decrease in serum IGF-1 concentration or with a sustained and biological relevant increase in serum cortisol. However, long-term CR in humans significantly and persistently increases serum IGFBP-1 concentration.

AB84. Characteristic of platelet-rich plasma and its effects on on improving neurogenic erectile dysfunction

Platelet-rich plasma (PRP) containing autologous thrombocyte growth factors is applied in regenerative medicine, but the lack of an optimized PRP preparation protocol causes unstable therapeutic effects. The aim of this study was to optimize the PRP preparation method to obtain the largest amount of growth factors released and compare the effects of PRP from different preparation methods in restoring of erectile function in bilateral cavernous nerve (CN) injury rat model. The in vivo experiments used Sprague-Dawley male rats (n=24) which were randomly divided into four groups of equal numbers: (I) sham operation; (II) vehicle only (which underwent bilateral nerve crushing without treatment); (III) general PRP; and (IV) optimized PRP containing the largest amount of platelet-derived growth factor (PDGF)-AB (groups 3 and 4 underwent bilateral CN crushing with an immediate injection of the respective PRP into the corpus cavernosum). The intracavernous pressure (ICP) of all rats was monitored. Results demonstrated that in the PRP group prepared with the anticoagulant, ACD-A, the amount of PDGF-AB released was statistically higher than those of the other groups (P<0.05). Greater concentrations of PDGF-AB were measured in PRP after chitosan treatment compared to treatment with a solvent or other activating factors. Additionally, storing PRP at –20 ℃ resulted in a significant increase in PDGF-AB released compared to storage at other temperatures. The optimized PRP prepared by stimulation with chitosan and incubated at –20 ℃ for 15 days had the largest amount of PDGF-AB and showed a synergistic effect on release (P<0.05). The functional outcome measurement revealed improvement after bilateral CN injury occurred in the group treated with optimized PRP. It was concluded that optimized PRP with a high level of growth factors was more stable, and its injection into the corpus cavernosum facilitated recovery of erectile function.

AB84. Characteristic of platelet-rich plasma and its effects on on improving neurogenic erectile dysfunction

Platelet-rich plasma (PRP) containing autologous thrombocyte growth factors is applied in regenerative medicine, but the lack of an optimized PRP preparation protocol causes unstable therapeutic effects. The aim of this study was to optimize the PRP preparation method to obtain the largest amount of growth factors released and compare the effects of PRP from different preparation methods in restoring of erectile function in bilateral cavernous nerve (CN) injury rat model. The in vivo experiments used Sprague-Dawley male rats (n=24) which were randomly divided into four groups of equal numbers: (I) sham operation; (II) vehicle only (which underwent bilateral nerve crushing without treatment); (III) general PRP; and (IV) optimized PRP containing the largest amount of platelet-derived growth factor (PDGF)-AB (groups 3 and 4 underwent bilateral CN crushing with an immediate injection of the respective PRP into the corpus cavernosum). The intracavernous pressure (ICP) of all rats was monitored. Results demonstrated that in the PRP group prepared with the anticoagulant, ACD-A, the amount of platelet-derived growth factor (PDGF)-AB released was statistically higher than those of the other groups (P<0.05). Greater concentrations of PDGF-AB were measured in PRP after chitosan treatment compared to treatment with a solvent or other activating factors. Additionally, storing PRP at –20 °C resulted in a significant increase in PDGF-AB released compared to storage at other temperatures. The optimized PRP prepared by stimulation with chitosan and incubated at -20 °C for 15 days had the largest amount of PDGF-AB and showed a synergistic effect on release (P<0.05). The functional outcome measurement revealed improvement after bilateral CN injury occurred in the group treated with optimized PRP. It was concluded that optimized PRP with a high level of growth factors was more stable, and its injection into the corpus cavernosum facilitated recovery of erectile function.

Concentration of Platelet Derived-Growth Factors in Concentrates Used to Regenerate Injured Bone Tissue

BACKGROUND. Bone union disorders of various kinds, of both iatrogenic and biological origin, are a common problem in the treatment of compound fractures. Impairment of bone regeneration often results from lack of biological potential for healing and lack of stimulation of osteogenesis at the site of bone loss. Bone union is stimulated by topical administration of a concentrate of platelet-derived growth factors. The aim of the study was to assess the concentration of platelet-derived growth factors in a concentrate before and after activation with a mixture of thrombin and calcium chloride. The study comprised 30 samples of platelet-derived growth factor concentrates. Platelets were activated with CaCl 2 and 20 IU of thrombin. The resultant clot was incubated for 30 min at 37°C and then centrifuged again. The platelet count and PDGF AB, TGFß 1 , VEGF and IGF-1 concentrations were determined in each sample. The measurements were performed in accordance with recommended procedures. In the case of PDGF AB, the procedure was modified by changing the number of dilutions. A nonparametric test (Spearman rank correlation) was used for the statistical analysis. RESULTS. The study showed that the platelet count in a PDGF concentrate was 6.27 times higher than in whole blood. PDGF AB concentration in the PDGF concentrate in our study increased 5-6 times after activation. Concentrations of other growth factors increased 1.2- to 2-fold after CaCl 2 - and thrombin-induced activation in comparison to whole blood levels. There were no statistically significant correlations between the platelet count and the concentration of particular growth factors. CONCLUSIONS. The study's findings showed that the method of obtaining a platelet-derived growth factor concentrate may be an effective method of obtaining a platelet-rich preparation with a high platelet count. The concentrations of the measured platelet-derived growth factors in the concentrate were several times higher than in whole blood samples.

Low concentration of PDGF-AB shows synergism with IFN-α in induction of IFN-β and -γ in MRC5 fibroblasts

Platelet-derived growth factor (PDGF) is a potent mediator of fibroblast proliferation and chemotaxis. Also it has been reported as a strong suppressor of interferon (IFN) expression. IFN-α has opposite effect on fibroblast function and IFN induction. Here is our early report on the effect of low concentration of PDGF-AB alone or in combination with IFN-α on IFN mRNA production in MRC5 fibroblasts. MRC5 cells incubated with IFN-α or PDGF-AB, alone or in combination, produced significant induction of IFN-α, -β and -γ mRNA in comparison with untreated cells. The induction was dose-dependent, with higher effect in cells treated with lower concentrations of PDGF-AB. Also, low concentration of PDGF-AB showed synergism with IFN-α in IFN-β and -γ induction. Results presented here open new possibilities in multi-cytokine therapy and expand previous results on PDGF activity.

Exercise and the platelet activator calcium chloride both influence the growth factor content of platelet-rich plasma (PRP): overlooked biochemical factors that could influence PRP treatment

BackgroundThere is strong evidence that exercise affects platelet haemostasis factors, but this potential effect on growth factor concentrations in platelet-rich plasma (PRP) has never been studied. In addition, there is...

Concentration of PDGF-AB, BB and TGF-β1 as Valuable Human Serum Parameters in Adipose-derived Stem Cell Proliferation

Human serum (HS) has attributes similar to fetal bovine serum (FBS) in the proliferation and differentiation of human adipose-derived stem cells (hASCs) when compared in vitro. The purpose of this study was to determine what types of HS, with respect to the concentrations of endogenous growth factors, could be made available for hASC proliferation. HS was collected from 2 groups of healthy donor (freshly isolated HS [n=9], and HS preserved for 4 years [n=7]). All sera were isolated with a Cellaid HS isolation device (JMS Co., Ltd, Hiroshima, Japan) and then classified into 3 groups based on the concentrations (high, middle, and low) of platelet-derived growth factor (PDGF)-AB, PDGF-BB, and transforming growth factor-beta 1 (TGF-β1) by means of enzyme-linked immunoassay screening. The hASCs were isolated from subcutaneous fat using a collagenase enzymatic digestion process and were cultured in control media, each supplemented with HS from a different group. Cell numbers were counted on days 2, 4, 7, and 14, and the relationship between cell proliferation and the level of each growth factor was investigated. The proliferation of hASCs correlated with the concentration of each growth factor. The cut-off points for PDGF-AB, PDGF-BB, and TGF-β1 in HS [necessary for hASC proliferation when compared with FBS] were 10 ng/mL, 1.5 ng/mL, and 15 ng/mL, respectively. There was no correlation between the storage period of HS and the proliferation potential of hASCs. These results suggest that the effectiveness of HS on hASC proliferation depends on the concentrations of endogenous PDGFs. In addition, the Cellaid device used in this study allows the simultaneous release of several growth factors from platelets, and our results have shown that it can be used to collect HS for future hASC-based therapies.

The Effect of Immediate and Delayed Injection of Platelet-Rich Plasma (PRP) on Muscle Contusion Healing in the Rat

Objectives:Muscle contusions are among the most common injuries in sport. Though typically self-limiting, more severe types of contusions can lead to marked pain and diminished function with significant delay in return-to-play. Current therapy is usually limited to NSAIDs and/or use of the RICE principle. Other forms of treatment that can potentially accelerate the rate of healing are desirable. Platelet-rich plasma (PRP) is a novel therapy produced from autologous whole blood that holds promise for treating muscle injuries. However, data both at the translational and clinical level is still limited. This study seeks to investigate the effects of PRP on muscle contusion healing in rats and to determine if the timing of injection plays any role in recovery.Methods:Forty-six (46) male Lewis rats each underwent blunt, non-penetrating impact to the gastrocnemius muscle via a drop-tower model. The rats were separated into 4 groups, with each rat undergoing injection into the injured gastrocnemius muscle according to the following schema: those in Group 1 underwent a single injection of 100ul of rat PRP on the day of injury; those in Group 2(controls) underwent a single injection of 100ul of saline on the day of injury; those in Group 3 underwent a single injection of 100ul rat PRP on post-injury day #1; those in Group 4 underwent a single injection of 100ul of rat PRP on post-injury day #3. After the injury, rats were allowed unrestricted activity. The primary outcome measurement was maximal isometric torque strength of the injured muscle, which was performed prior to impaction injury as well as on post-injury days 1, 4, 7, 10, and 14. All animals were sacrificed on post-injury day 15.Results:Mean rat weight was 319 (±15) grams. The mean platelet concentration in the PRP solution was 2.19x106 (±2.69x105) per ul, which was greater than 4 times whole blood baseline levels and the concentration of PDGF-AB, VEGF, and TGF-β was increased by a factor of 2.6, 1.8, and 2.7, respectively. Each group demonstrated statistically significant decreases in maximal isometric torque strength after injury, followed by significant increases back towards baseline values by post-injury day 14 (figure 1). There were no statistically significant differences between the treatment and control groups at any of the time-points.Conclusion:PRP is being used clinically to treat numerous soft tissue injuries, though clinical data is limited. In this rat contusion model, local injection of PRP into the injured gastrocnemius muscle resulted in no significant differences in maximal isometric torque strength at various post-injury time-points, indicating no likely benefit to healing. Additionally, there was no significant difference between immediate or delayed administration of PRP. Further translational and clinical investigation needs to be performed before PRP can be recommended for the treatment of muscle contusion injuries.

Platelet Lysate Mucohadesive Formulation to Treat Oral Mucositis in Graft Versus Host Disease Patients: A New Therapeutic Approach

Optimal treatment of oral mucositis (OM) due to graft versus host disease (GvHD) is currently not available. Platelet-derived growth factors (PDGFs) have high capability for tissue healing and may play a role in repairing the mucosal barrier. The aim of the present work was to develop a mucoadhesive formulation to administer platelet lysate to oral cavity prolonging contact time of platelet lysate with oral mucosa. The mucoadhesive formulation was characterized for in vitro properties (PDGF-AB concentration, mucoadhesive properties, cytotoxicity, fibroblast proliferation, wound healing). Moreover, a preliminary clinical study on seven GvHD patients with OM refractory to other therapies was conducted, to evaluate feasibility, safety, and efficacy. GVPL (mucoadhesive gel vehicle mixed with platelet lysate)showed good mucoadhesive properties; additionally, it was characterized by good biocompatibility in vitro on fibroblasts and it was able to enhance fibroblast proliferation and wound healing, maintaining the efficacy for up to 14 days following storage at 2-8°C. In vivo, clinical response was good-to-complete in five, fair in one, none in the remaining one. The in vitro results indicate that GVPL has optimal mucoadhesive and healing enhancer properties, maintained over time (up to 14 days); preliminary clinical results suggest that oral application of platelet lysate-loaded mucoadhesive formulation is feasible, safe, well tolerated, and effective. A larger controlled randomized study is needed.

Autologous Platelet Gel Fails to Show Beneficial Effects on Wound Healing after Saphenectomy in CABG Patients

Wound healing impairment in the leg after removal of the saphenous vein within the framework of a coronary artery bypass graft (CABG) operation represents a clinically significant problem. Patients suffer from this complication, and treatment of the wounds is costly in terms of both time and money. No method is known to date that reliably prevents postoperative wound healing disturbances. The effect of autologous platelet gel to stimulate wound healing is known from various medical disciplines. Within a prospective randomized study, we wanted to determine whether intraoperative use of autologous platelet gel on the leg during a CABG operation could reduce the incidence of postoperative wound healing disturbances. The application group (AG) included 35 patients and was compared to a control group (CG) that also had 35 patients. The platelet gel, as well as the thrombin required to activate the platelets, was prepared from autologous patient blood during the operation. Validation of the platelet gel comprised measurement of the growth factors platelet–derived growth factor AB (PDGF AB) and epidermal growth factor (EGF), as well as the thrombocyte and leukocyte counts. Wound healing was photographically documented after surgery, and the patients were contacted by telephone on day 50 after surgery to obtain information on wound healing status. After cell separation, the platelet count was 1616 ± 845/μL, which is higher than in whole blood by a factor of 7.1 ± 2.0, with a platelet yield of 47.0% ± 13.2%. The PDGF AB concentration after activation of the platelets was raised by a median factor of 158 and EGF by a median factor of 64 compared with whole blood. During the primary clinical stay, no statistically significant differences were recorded in the number of hematomas, postoperative leg swelling, or pain level. Large-area hematomas were less frequent in the application group (AG, 29.4% vs. CG, 60%,p= .007). In the follow-up 51 ± 9 days after surgery, 17.6% (6/34) of the patients from the AG and 31.4% (11/35) of the patients from the CG showed leg wound healing disturbances (p= .184). Using the cell separation system, a biological product that contains high concentrations of platelets, leukocytes, and growth factors can be prepared reproducibly. Despite optimum application of the autologous platelet gel to the wound, no clinically relevant differences were found between the groups, either during the primary clinic stay or in the follow-up period.

Phase II Evaluation of Imatinib Mesylate in the Treatment of Recurrent or Persistent Epithelial Ovarian or Primary Peritoneal Carcinoma: A Gynecologic Oncology Group Study

This phase II trial assessed the activity and tolerability of an oral dose of imatinib mesylate 400 mg twice daily in patients with recurrent or persistent epithelial ovarian or primary peritoneal carcinoma. The association between the expression of certain markers and clinical outcome was investigated. Primary measure of clinical efficacy was progression-free survival (PFS) at 6 months. Mutational analysis of KIT, immunohistochemistry (IHC) and enzyme-linked immunosorbent assay for markers (KIT, platelet-derived growth factor [PDGF] receptor [-R], AKT2, phosphorylated AKT [p-AKT], stem cell factor [SCF], and PDGF) were performed. Fifty-six eligible patients were evaluated. Nine patients were progression free for at least 6 months including one complete responder. The median PFS and survival were 2 and 16 months, respectively. The most common grade 3 and 4 toxicities were neutropenia, GI, dermatologic effects, pain, and electrolyte disturbances. At least one target of imatinib (KIT, PDGFR-alpha, or PDGFR-beta) was expressed in all tumors, and most tumors expressed all three receptors. Higher expression of p-AKT and PDGFR-beta were associated with shorter PFS, and higher IHC scores (% immunopositive cells x staining intensity) of SCF and p-AKT were associated with decreased overall survival. No sequence mutations were detected in the KIT gene. Higher pretreatment plasma concentrations of PDGF-AB, PDGF-BB, and vascular endothelial growth factor (VEGF) were individually associated with shorter PFS and survival. Imatinib mesylate was well tolerated but had minimal single-agent activity in patients with recurrent ovarian or primary peritoneal carcinoma. No marker was identified that would predict activity of imatinib; however, tumor p-AKT and plasma VEGF levels were associated with poor outcome.

Toll‐like receptor 4 ligand can differentially modulate the release of cytokines by human platelets

Blood platelets link the processes of haemostasis and inflammation. This study examined the immunomodulatory factors released by platelets after Toll-Like Receptor 4 (TLR4) engagement on their surfaces. Monoclonal anti-human FcgammaRII Ab (IV.3)-treated human platelets were cultured with TLR4 ligands in the presence or absence of blocking monoclonal antibody to human TLR4. The release of sCD62p, epidermal growth factor (EGF), transforming growth factor beta (TGFbeta), interleukin (IL)-8, platelet activating factor 4 (PAF4), platelet-derived growth factor, alpha, beta polypeptide (PDGF-AB), Angiogenin, RANTES (regulated upon activation, normal T-cell expressed, and presumably secreted) and sCD40L were measured by specific enzyme-linked immunosorbent assay. TLR4 ligand [Escherichia coli lipopolysaccharide (LPS)] bound platelet TLR4, which differentially modulates the release of cytokines by platelets. It was noted that (i) sCD62p, IL-8, EGF and TGFbeta release were each independent of platelet activation after TLR4 engagement; (ii) RANTES, Angiogenin and PDGF-AB concentration were weaker in platelet supernatant after TLR4 engagement; (iii) sCD40L and PAF4 are present in large concentration in the releaseate of platelets stimulated by TLR4 ligand. The effects of LPS from E. coli on the modulation of secretory factors were attenuated by preincubation of platelets with an anti-TLR4 monoclonal antibody, consistent with the immunomodulation being specifically mediated by the TLR4 receptor. We propose that platelets adapt the subsequent responses, with polarized cytokine secretion, after TLR4 involvement.

Effect of Different Bone Substitutes on the Concentration of Growth Factors in Platelet-rich Plasma

This study is conducted to determine the effect of different kinds of bone substitutes and collagen on the concentration of platelet-derived growth factor (PDGF) and transforming growth factor beta-1 (TGF beta-1) in platelet-rich plasma (PRP). PRP is treated with thrombin, hydroxyapatite (HA), and thrombin, HA alone, collagen-grafted HA, calcium metaphosphate (CMP), and collagen-grafted CMP. The concentrations of PDGF-AB and TGF beta-1 are measured. After PRP treated with HA and CMP, the concentrations of PDGF and TGF beta-1 are not significantly different from the concentration of them in PRP alone. The concentrations of PDGF in PRP with collagen-grafted HA and collagen-grafted CMP are significantly higher than that of PRP with HA and CMP. The concentrations of PDGF and TGF beta-1 in PRP with collagen-grafted CMP are higher than with collagen-grafted HA. The results of multiple regression analysis show that PDGF increased with the use of collagen and thrombin, and is higher in native whole blood with higher platelet counts. However, PDGF decreased with the use of HA. In conclusion, HA and CMP do not seem to be able to activate platelets by themselves. However, if they had collagen grafted onto them, they could activate platelets and release growth factors.