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1.  Synergistic Effect of Bone Marrow-Derived Mesenchymal Stem Cells and Platelet-Rich Plasma in Streptozotocin-Induced Diabetic Rats 
Annals of Dermatology  2014;26(1):1-10.
Background
Diabetic wounds are a major clinical challenge, because minor skin wounds can lead to chronic, unhealed ulcers and ultimately result in infection, gangrene, or even amputation. Studies on bone marrow derived mesenchymal stem cells (BMSCs) and a series of growth factors have revealed their many benefits for wound healing and regeneration. Platelet-rich plasma (PRP) may improve the environment for BMSC development and differentiation. However, whether combined use of BMSCs and PRP may be more effective for accelerating diabetic ulcer healing remains unclear.
Objective
We investigated the efficacy of BMSCs and PRP for the repair of refractory wound healing in a diabetic rat model.
Methods
Forty-eight rats with diabetes mellitus induced by streptozotocin were divided into four groups: treatment with BMSCs plus PRP, BMSCs alone, PRP alone, phosphate buffered saline. The rate of wound closure was quantified. A histopathological study was conducted regarding wound depth and the skin edge at 7, 14, and 28 days after surgery.
Results
Wound healing rates were significantly higher in the BMSC plus PRP group than in the other groups. The immunohistochemistry results showed that the expression of platelet/endothelial cell adhesion molecule 1, proliferating cell nuclear antigen, and transforming growth factor-β1 increased significantly in the BMSC plus PRP group compared to the other treatment groups. On day 7, CD68 expression increased significantly in the wounds of the BMSC plus PRP group, but decreased markedly at day 14 compared to the controls.
Conclusion
The combination of BMSCs and PRP aids diabetic wound repair and regeneration.
doi:10.5021/ad.2014.26.1.1
PMCID: PMC3956772  PMID: 24648680
Bone marrow-derived mesenchymal stem cell; Diabetes mellitus; Platelet-rich plasma; Wounds
2.  Platelet-Rich Plasma Combined With Skin Substitute for Chronic Wound Healing: A Case Report 
Abstract:
Contemporary management of chronic wounds focuses on improving natural healing and individualization of treatment. Incorporating multiple therapies has become increasingly common. Of interest are autologous growth factors, which are especially important in chronic wound healing and may contribute to tissue formation and epithelialization. Autologous platelet concentrate or platelet-rich plasma (PRP) is a concentration of at least five autologous growth factors and has been shown to accelerate wound healing and may have infection-fighting properties. Chronic wound healing is complicated by both decreased growth factor availability and infection, making PRP use valuable in these types of wounds. In this report, the use of PRP therapy alone and in combination with a bioengineered skin substitute as a platelet-rich tissue graft in a chronic, non-healing wound is detailed. Over 27 weeks, the patient received multiple therapies in attempts to heal a severe decubitus ulcer of the sacrum. The introduction of PRP therapy at Week 14 led to a 26% reduction in wound depth over 4 weeks. At Week 19, PRP therapy was combined with a powdered skin substitute to create a platelet-rich tissue graft. The combination brought dramatic results, eliminating wound tunneling and reducing the wound dimensions from 6.2 cm long × 6.7 cm wide × 2.7 cm deep to 5.0 cm long × 6.0 cm wide × 1.4 cm deep. The promising observations from this case report indicate that further study on the combining of PRP therapy and skin substitutes is necessary.
PMCID: PMC4680819  PMID: 17089514
platelet-rich plasma; chronic wounds; growth factors; skin substitutes; infection
3.  Customized Platelet-Rich Plasma for Skeletal Muscle Injuries 
Orthopaedic Journal of Sports Medicine  2016;4(7 suppl4):2325967116S00143.
Objectives:
Skeletal muscle injuries are among the most common sports-related trauma. Current treatment strategies result in formation of fibrous tissue that hinders the healing process before complete recovery. Incomplete recovery impairs muscle function and predisposes to re-injury. Platelet-Rich-Plasma (PRP) contains a multitude of growth factors and is an autologous source of growth factors for various tissue repairs. It is well established that PRP contains beneficial growth factors for muscle repair; however, it also contains high concentrations of deleterious growth factors for optimal muscle healing, such as transforming growth factor-beta 1 (TGF-β1). TGF-β1 leads to increased fibrosis impeding muscle healing. We therefore hypothesized that neutralization of TGF-β1’s action within PRP could improve PRP’s beneficial effect on skeletal muscle repair.
Methods:
Sixteen week old in-bred Fisher rats were used. Three rats were used for PRP isolation. 10 ml of blood were extracted from abdominal aorta and mixed with citrate phosphate dextrose solution. PRP were isolated by twice centrifugation. 24 rats were randomly assigned to four groups. A small incision was made along the tibialis anterior (TA) muscle; 50 µl cardiotoxin (CTX) (0.15ug/ul) was injected intramuscularly to the TA. One day after CTX injection, the animals were treated with PBS (control), plain PRP (PRP group), customized PRP+Ab-1x, and PRP+Ab-5x. Animals were sacrificed, and TA muscles were dissected on week 1 and 2 for assessment of muscle regeneration, fibrosis, macrophage infiltration, and satellite cell activation.
Results:
We observed significantly more regenerative myofibers in the PRP and customized PRP groups compared to control (Fig 1A-C). Collagen deposition (fibrosis) was detected in all groups at week 1 and week 2 after injury; while customized PRP group showed significantly decreased collagen deposition at week 1 and week 2 when compare to control and PRP groups (Fig. 1D-F). PRP was also shown to activate satellite cells at day 7 while customized PRP extended satellite cell activation through day 14 (Fig. 1G, H). Macrophage infiltration was significantly decreased in PRP group when compared to control at week 1 after injury; however the macrophage infiltration was increased in customized PRP group when compare with PRP group, specifically, we observed an increased in the percentage of the M2 macrophage subtype in the customized PRP group at week 1 but not week 2(Fig. 1I, J).
Conclusion:
This study demonstrates that substantial fibrosis occurs in skeletal muscle following CTX injury. PRP treatment significantly increases muscle regeneration by promoting angiogenesis, satellite cell activation, and reducing the infiltration of inflammatory macrophages. However, augmented fibrosis was also observed. Neutralizing TGF-β1 within PRP also significantly promotes muscle regeneration while significantly reducing fibrosis. It has been suggested that M2 macrophages are involved in the suppression, resolution and reversal of fibrosis. Hence, the increase in M2 macrophages in the customized PRP group may have contributed to the observed decrease in fibrosis. Our results demonstrate that neutralization of TGF-β1 within PRP is a promising approach to improve PRP’s beneficial effect on skeletal muscle repair while decreasing deleterious fibrosis.
doi:10.1177/2325967116S00143
PMCID: PMC4968283
4.  Platelet-rich plasma (PRP) in dental and oral surgery: from the wound healing to bone regeneration 
Platelet-rich plasma (PRP) is a new approach to tissue regeneration and it is becoming a valuable adjunct to promote healing in many procedures in dental and oral surgery, especially in aging patients. PRP derives from the centrifugation of the patient's own blood and it contains growth factors that influence wound healing, thereby playing an important role in tissue repairing mechanisms. The use of PRP in surgical practice could have beneficial outcomes, reducing bleeding and enhancing soft tissue healing and bone regeneration. Studies conducted on humans have yielded promising results regarding the application of PRP to many dental and oral surgical procedures (i.e. tooth extractions, periodontal surgery, implant surgery). The use of PRP has also been proposed in the management of bisphosphonate-related osteonecrosis of the jaw (BRONJ) with the aim of enhancing wound healing and bone maturation. The aims of this narrative review are: i) to describe the different uses of PRP in dental surgery (tooth extractions and periodontal surgery) and oral surgery (soft tissues and bone tissue surgery, implant surgery and BRONJ surgery); and ii) to discuss its efficacy, efficiency and risk/benefit ratio. This review suggests that the use of PRP in the alveolar socket after tooth extractions is certainly capable of improving soft tissue healing and positively influencing bone regeneration but the latter effect seems to decrease a few days after the extraction. PRP has produced better results in periodontal therapy in association with other materials than when it is used alone. Promising results have also been obtained in implant surgery, when PRP was used in isolation as a coating material. The combination of necrotic bone curettage and PRP application seem to be encouraging for the treatment of refractory BRONJ, as it has proven successful outcomes with minimal invasivity. Since PRP is free from potential risks for patients, not difficult to obtain and use, it can be employed as a valid adjunct in many procedures in oral and dental surgery. However, further RCTs are required to support this evidence.
doi:10.1186/1742-4933-10-23
PMCID: PMC3683340  PMID: 23763951
PRP; Wound healing; Bone regeneration; Dental surgery; Oral surgery; Tooth extraction; Periodontal surgery; Implant surgery; BRONJ
5.  Modification of Pulsed Electric Field Conditions Results in Distinct Activation Profiles of Platelet-Rich Plasma 
PLoS ONE  2016;11(8):e0160933.
Background
Activated autologous platelet-rich plasma (PRP) used in therapeutic wound healing applications is poorly characterized and standardized. Using pulsed electric fields (PEF) to activate platelets may reduce variability and eliminate complications associated with the use of bovine thrombin. We previously reported that exposing PRP to sub-microsecond duration, high electric field (SMHEF) pulses generates a greater number of platelet-derived microparticles, increased expression of prothrombotic platelet surfaces, and differential release of growth factors compared to thrombin. Moreover, the platelet releasate produced by SMHEF pulses induced greater cell proliferation than plasma.
Aims
To determine whether sub-microsecond duration, low electric field (SMLEF) bipolar pulses results in differential activation of PRP compared to SMHEF, with respect to profiles of activation markers, growth factor release, and cell proliferation capacity.
Methods
PRP activation by SMLEF bipolar pulses was compared to SMHEF pulses and bovine thrombin. PRP was prepared using the Harvest SmartPreP2 System from acid citrate dextrose anticoagulated healthy donor blood. PEF activation by either SMHEF or SMLEF pulses was performed using a standard electroporation cuvette preloaded with CaCl2 and a prototype instrument designed to take into account the electrical properties of PRP. Flow cytometry was used to assess platelet surface P-selectin expression, and annexin V binding. Platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), endothelial growth factor (EGF) and platelet factor 4 (PF4), and were measured by ELISA. The ability of supernatants to stimulate proliferation of human epithelial cells in culture was also evaluated. Controls included vehicle-treated, unactivated PRP and PRP with 10 mM CaCl2 activated with 1 U/mL bovine thrombin.
Results
PRP activated with SMLEF bipolar pulses or thrombin had similar light scatter profiles, consistent with the presence of platelet-derived microparticles, platelets, and platelet aggregates whereas SMHEF pulses primarily resulted in platelet-derived microparticles. Microparticles and platelets in PRP activated with SMLEF bipolar pulses had significantly lower annexin V-positivity than those following SMHEF activation. In contrast, the % P-selectin positivity and surface P-selectin expression (MFI) for platelets and microparticles in SMLEF bipolar pulse activated PRP was significantly higher than that in SMHEF-activated PRP, but not significantly different from that produced by thrombin activation. Higher levels of EGF were observed following either SMLEF bipolar pulses or SMHEF pulses of PRP than after bovine thrombin activation while VEGF, PDGF, and PF4 levels were similar with all three activating conditions. Cell proliferation was significantly increased by releasates of both SMLEF bipolar pulse and SMHEF pulse activated PRP compared to plasma alone.
Conclusions
PEF activation of PRP at bipolar low vs. monopolar high field strength results in differential platelet-derived microparticle production and activation of platelet surface procoagulant markers while inducing similar release of growth factors and similar capacity to induce cell proliferation. Stimulation of PRP with SMLEF bipolar pulses is gentler than SMHEF pulses, resulting in less platelet microparticle generation but with overall activation levels similar to that obtained with thrombin. These results suggest that PEF provides the means to alter, in a controlled fashion, PRP properties thereby enabling evaluation of their effects on wound healing and clinical outcomes.
doi:10.1371/journal.pone.0160933
PMCID: PMC4996457  PMID: 27556645
6.  Platlet Rich Plasma (PRP) Improves Fat Grafting Outcomes 
Autologous fat transfer offers many qualities of a ideal soft tissue filler. Main advantages of fat grafting ensue from the fact that the lipoaspirate tissue is an abundant source of regenerative pluripotential cells. However, the reported rates of fat cell survival vary greatly in the medical literature (10-90%). Different techniques of harvesting, processing, and reinjecting the fat cells are so claimed to be responsible for these differences, without any agreement concerning the best way to process. To address this important disadvantage, we propose the addition of autologous platelet rich plasma (PRP) which is known as a natural reservoir of growth factors stimulating tissue repair and regeneration. This approach is completely autologous and immediately employed without any type of preconditioning. Platelets rich plasma (PRP) preparation included bleeding of 8 ml of blood from patient’s peripheral vein in Regen Lab© tubes containing sodium citrate anticoagulant. The whole blood was centrifugated at 1500 g during 3 min. As Regen-tubes contained a special gel separator, 99 % of red blood cells were discarded from the plasma at the bottom of the gel, and >90% of platelets were harvested in 4 ml of plasma on the top of the gel, called the platelet-rich plasma (PRP). The purified fat prepared by Coleman technique was mixed with different amount of PRP for in vitro, in vivo (mice) and clinical experiments: >50% of PRP for skin rejuvenation, superficial scars correction, infraorbital region, ..., and for 20% of PRP with 80% of purified fat for deep filler indication (nasolabial folds, lips, or soft tissue defect). In vitro studies demonstrated that PRP increased fat cells survival rate and stem cells differentiation. Animal models showed that fat graft survival rate was significantly increased by addition of PRP. Several clinical cases confirmed the improvement of wound healing and fat grafting survival in facial reconstruction and aesthetic cases by association of fat grafting with PRP. The addition of PRP to fat grafts represented many advantages with a simple, cost-effective and safe method. In addition to its booster effect on fat grafts, PRP had a rejuvenation capacity per se. It is also used on nappage technique, on mask and as a temporary regenerative filler in combination with thrombin. So we consider the addition of 20% PRP to fat grafts offers a better fat grafting survival, a less bruising and inflammation reaction, and easier application of fat grafts due to liquefaction effect of PRP.
PMCID: PMC4238337  PMID: 25489498
Platlet rich plasma; PRP; Fat; Graft; Outcome
7.  A Prospective Study Involving the Use of Platelet Rich Plasma in Enhancing the Uptake of Bone Grafts in the Oral and Maxillofacial Region 
Abstract
Platelet-rich plasma (PRP) is an autologous product that contains highly concentrated number of platelets in a small volume of plasma, derived from whole blood by gradient density centrifugation. It has been speculated that local growth factors in human platelets (insulin-like growth factor, IGF; transforming growth factor, TGF-β; platelet derived growth factor, PDGF) would enhance healing of grafts and also counteract resorption. The aim of this study was to evaluate efficacy of PRP on early healing after autogenous bone grafting. Of the twenty patients selected ten were treated with autogenous bone graft and PRP (PRP group) and other ten with autogenous bone graft alone (non-PRP group). PRP group consisted of two benign tumor of mandible, one post surgical defect, two unilateral alveolar cleft, one bilateral alveolar cleft with skeletal class III malocclusion, one maxillary hypoplasia, one oronasal fistula, one recurrent tumor of mandible, one multiple impacted mandibular teeth. Non-PRP group consisted of seven benign tumor of jaw, one keratocyst odontogenic tumor, one orbital blow out fracture, one residual traumatic defect. Biopsies were taken in the native bone, PRP treated grafted bone, grafted bone without PRP at 3 months to assess the maturity of bone. Radiographic imaging was performed by panoramic radiography at 3 and 6 months to evaluate bone opacity of grafted bone on comparison with native bone and computerized tomography at 6 months to evaluate grafted bone morphologically and to measure bone density in Hounsfield units. Microscopic results showed that significantly more matured bone was formed at PRP treated sites as that of native bone and immature bone in controls after 3 months of healing. Bone opacity of PRP treated bone grafts was close to that of native bone than that of non-PRP treated bone grafts on panoramic radiograph at 3 and 6 months. There was graft loss in three cases and graft resorption in one case of non-PRP treated bone grafts at 6 months. In PRP group the compact bone was clearly differentiated from cancellous bone as in native bone and thick in five cases, thin in five cases. In non-PRP group the compact bone was thin as a whole. Comparing native bone group and PRP group the CT value of PRP treated bone graft was more or less close to native bone group and comparing native bone group and non-PRP group CT value was low in non-PRP treated bone graft. Whereas when comparing PRP and non-PRP group CT value was higher in PRP group. Autologous PRP was a safe, biocompatible, effective, source for growth factors and carries no risk of transmissible diseases. It enhances and accelerates bone regeneration of autogenous bone grafts.
doi:10.1007/s12663-012-0466-3
PMCID: PMC3847021  PMID: 24431876
Platelet-rich plasma; Mandibular reconstruction; Nonvascularised bone grafts; Alveolar bone grafting; Hounsfield unit
8.  Enhanced skin wound healing by a sustained release of growth factors contained in platelet-rich plasma 
Experimental & Molecular Medicine  2011;43(11):622-629.
Platelet-rich plasma (PRP) contains growth factors that promote tissue regeneration. Previously, we showed that heparin-conjugated fibrin (HCF) exerts the sustained release of growth factors with affinity for heparin. Here, we hypothesize that treatment of skin wound with a mixture of PRP and HCF exerts sustained release of several growth factors contained in PRP and promotes skin wound healing. The release of fibroblast growth factor 2, platelet-derived growth factor-BB, and vascular endothelial growth factor contained in PRP from HCF was sustained for a longer period than those from PRP, calcium-activated PRP (C-PRP), or a mixture of fibrin and PRP (F-PRP). Treatment of full-thickness skin wounds in mice with HCF-PRP resulted in much faster wound closure as well as dermal and epidermal regeneration at day 12 compared to treatment with either C-PRP or F-PRP. Enhanced skin regeneration observed in HCF-PRP group may have been at least partially due to enhanced angiogenesis in the wound beds. Therefore, this method could be useful for skin wound treatment.
doi:10.3858/emm.2011.43.11.070
PMCID: PMC3249588  PMID: 21847007
angiogenesis inducing agents; endothelial growth factors; fibrin; fibroblast growth factor 2; heparin; neovascularization, physiologic; platelet-derived growth factor; platelet-rich plasma; wound healing
9.  Utilization of Platelet-Rich Plasma for a Fistula With Subcutaneous Cavity Following Septic Bursitis: A Case Report 
Eplasty  2015;15:e31.
In platelet-rich plasma (PRP) therapy, various growth factors and cytokines released the α-granules contained in platelets after activation can potentially enhance wound healing by delivering. We report a patient in whom treatment with PRP, prepared using a syringe-centrifugation-system PRP kit (KYOCERA Medical PRP Kit), for a fistula following bursitis of the lateral malleolus, which could not be healed with conventional wound therapy, led to successful healing. A 58-year-old man was on dialysis for type II diabetes and chronic renal failure. In the left lateral malleolus, septic bursitis developed, leading to a refractory fistula with a subcutaneous cavity measuring 4 × 3 cm, which persisted for more than 2 months. Platelet-rich plasma was prepared using the KYOCERA Medical PRP Kit (KYOCERA Medical Corporation, Osaka, Japan) and infused into the cavity twice to close it. After this procedure, the cavity size reduced, but the orifice and subcutaneous cavity were not closed. Therefore, additional PRP therapy was conducted after 10 weeks of the first PRP session. Complete closure was achieved 13 weeks after the first PRP therapy. In the present case, PRP was prepared using the KYOCERA Medical PRP Kit, and wound healing of a fistula with subcutaneous cavity following bursitis of the lateral malleolus was successfully cured. The KYOCERA Medical PRP Kit was useful, because PRP could be prepared simply and inexpensively using the syringe-centrifugation system.
PMCID: PMC4516017  PMID: 26221200
platelet-rich plasma; wound healing; fistula; subcutaneous cavity; septic bursitis
10.  Application of Autologous Platelet-Rich Plasma (PRP) on Wound Healing After Caesarean Section in High-Risk Patients 
Background
Platelet-rich plasma (PRP) is a human plasma product enriched by platelets, growth factors, and fibrinogen with high hemostatic and healing properties.
Objectives
The aim of this study was to evaluate the effect of autologous PRP on wound healing in high-risk women undergoing cesarean sections.
Patients and Methods
In this balanced, randomized, and controlled trial, 140 patients were admitted to Arash women’s hospital, Tehran, Iran from May of 2013 to November of 2014 for elective cesarean surgery. The patients were randomly assigned into two groups. The intervention group received PRP after surgery, whereas the control group received the usual care. All patients were evaluated at baseline, five days, and eight weeks after the cesarean section. The primary endpoint used the REEDA scale for assessing the changes in wound healing. The secondary outcome measures used were the Vancouver scar scale (VSS) and the visual analog scale (VAS). All scale scores were analyzed using a repeated measures test for variance.
Results
At the end of study, the PRP group showed a greater reduction in the edema ecchymosed discharge approximation (REEDA) score compared to the control group (85.5% reduction in the PRP group; 72% in the control group) (P < 0.001). Compared with the control group, the PRP group had a significantly greater reduction in the VAN score, beginning on the fifth day after the cesarean section (-0.7, 38% reduction in PRP group; -0.8, 33% in control group) (P < 0.001), and this trend was stable at the end of the eighth week (-0.6, 54% reduction in PRP group; -0.3, 18% in control group). Furthermore, patients treated with PRP experienced a 93% reduction in the VAS score at the end of follow-up, but the control group only observed a 79% reduction (P < 0.001).
Conclusions
It seems that applying PRP is an effective therapeutic approach for wound healing, and faster wound healing is expected due to the presence of more platelets and growth factors.
doi:10.5812/ircmj.34449
PMCID: PMC5027131  PMID: 27660723
Platelet-Rich Plasma; Caesarean Section; Wound Healing
11.  Characterization of the cytokine profile of platelet rich plasma (PRP) and PRP-induced cell proliferation and migration: Upregulation of matrix metalloproteinase-1 and -9 in HaCaT cells 
The Korean Journal of Hematology  2011;46(4):265-273.
Background
The underlying rationale of platelet rich plasma (PRP) therapy is that an injection of concentrated PRP at the site of injury may promote tissue repair via cytokine release from platelets. The molecular mechanisms of PRP therapy in the skin wound healing process are not well understood at present, and would benefit from clarification.
Methods
PRP was stimulated with angonists for 5 min, and cytokine profile analysis was performed. To investigate the wound healing activity of PRP, cell proliferation and migration analyses were performed in skin cells. The effects of PRP were analyzed on the expression and activity of matrix metalloproteinase (MMP)-1, -2, -9, and the activation of transcription factors.
Results
Thrombin was found to be a strong stimulator of PRP activation to release growth factors and chemokines. PRP induced cell proliferation and migration in HUVECs, HaCaT cells, and HDFs, as well as MMP-1and MMP-9 expression in HaCaT cells, but PRP did not have a significant effect on the expression or activity of MMPs in HDFs. The transcription factors, including signal transducer and activator of transcription-3 (STAT-3) were found to be phosphorylated following PRP treatment in HaCaT cells.
Conclusion
In this study, we have identified the cytokine profile of activated PRP after agonist stimulation. We have shown that PRP plays an active role in promoting the proliferation and migration of skin cells via the regulation of MMPs, and this may be applicable to the future development of PRP therapeutics to enhance skin wound healing.
doi:10.5045/kjh.2011.46.4.265
PMCID: PMC3259519  PMID: 22259633
Platelet rich plasma (PRP); Wound healing; Cytokine profile; Cell proliferation; Cell migration; Matrix metalloproteinase
12.  Platelet-Rich Plasma and Adipose-Derived Mesenchymal Stem Cells for Regenerative Medicine-Associated Treatments in Bottlenose Dolphins (Tursiops truncatus) 
PLoS ONE  2014;9(9):e108439.
Dolphins exhibit an extraordinary capacity to heal deep soft tissue injuries. Nevertheless, accelerated wound healing in wild or captive dolphins would minimize infection and other side effects associated with open wounds in marine animals. Here, we propose the use of a biological-based therapy for wound healing in dolphins by the application of platelet-rich plasma (PRP). Blood samples were collected from 9 different dolphins and a specific and simple protocol which concentrates platelets greater than two times that of whole blood was developed. As opposed to a commonly employed human protocol for PRP preparation, a single centrifugation for 3 minutes at 900 rpm resulted in the best condition for the concentration of dolphin platelets. By FACS analysis, dolphin platelets showed reactivity to platelet cell-surface marker CD41. Analysis by electron microscopy revealed that dolphin platelets were larger in size than human platelets. These findings may explain the need to reduce the duration and speed of centrifugation of whole blood from dolphins to obtain a 2-fold increase and maintain proper morphology of the platelets. For the first time, levels of several growth factors from activated dolphin platelets were quantified. Compared to humans, concentrations of PDGF-BB were not different, while TGFβ and VEGF-A were significantly lower in dolphins. Additionally, adipose tissue was obtained from cadaveric dolphins found along the Spanish Mediterranean coast, and adipose-derived mesenchymal stem cells (ASCs) were successfully isolated, amplified, and characterized. When dolphin ASCs were treated with 2.5 or 5% dolphin PRP they exhibited significant increased proliferation and improved phagocytotic activity, indicating that in culture, PRP may improve the regenerative capacity of ASCs. Taken together, we show an effective and well-defined protocol for efficient PRP isolation. This protocol alone or in combination with ASCs, may constitute the basis of a biological treatment for wound-healing and tissue regeneration in dolphins.
doi:10.1371/journal.pone.0108439
PMCID: PMC4177220  PMID: 25251412
13.  Autologous Growth Factor Injections in Chronic Tendinopathy 
Journal of Athletic Training  2014;49(3):428-430.
Reference:
de Vos RJ, van Veldhoven PLJ, Moen MH, Weir A, Tol JL. Autologous growth factor injections in chronic tendinopathy: a systematic review. Br Med Bull. 2010;95:63–77.
Clinical Question:
The authors of this systematic review evaluated the literature to critically consider the effects of growth factors delivered through autologous whole-blood and platelet-rich–plasma (PRP) injections in managing wrist-flexor and -extensor tendinopathies, plantar fasciopathy, and patellar tendinopathy. The primary question was, according to the published literature, is there sufficient evidence to support the use of growth factors delivered through autologous whole-blood and PRP injections for chronic tendinopathy?
Data Sources:
The authors performed a comprehensive, systematic literature search in October 2009 using PubMed, MEDLINE, EMBASE, CINAHL, and the Cochrane library without time limits. The following key words were used in different combinations: tendinopathy, tendinosis, tendinitis, tendons, tennis elbow, plantar fasciitis, platelet rich plasma, platelet transfusion, and autologous blood or injection. The search was limited to human studies in English. All bibliographies from the initial literature search were also viewed to identify additional relevant studies.
Study Selection:
Studies were eligible based on the following criteria: (1) Articles were suitable (inclusion criteria) if the participants had been clinically diagnosed as having chronic tendinopathy; (2) the design had to be a prospective clinical study, randomized controlled trial, nonrandomized clinical trial, or prospective case series; (3) a well-described intervention in the form of a growth factor injection with either PRP or autologous whole blood was used; and (4) the outcome was reported in terms of pain or function (or both).
Data Extraction:
All titles and abstracts were assessed by 2 researchers, and all relevant articles were obtained. Two researchers independently read the full text of each article to determine if it met the inclusion criteria. If opinions differed on suitability, a third reviewer was consulted to reach consensus. The data extracted included number of participants, study design, inclusion criteria, intervention, control group, primary outcome measures (pain using a visual analog or ordinal scale or function), time of follow-up, and outcomes for intervention and control group (percentage improvement) using a standardized data-extraction form. Function was evaluated in 9 of the 11 studies using (1) the Nirschl scale (elbow function) or the modified Mayo score for wrist flexors and extensors, (2) the Victorian Institute of Sports Assessment-Patella score, a validated outcome measure for patellar tendinopathy, or the Tegner score for patellar tendinopathy, and (3) the rearfoot score from the American Orthopaedic Foot and Ankle Scale for plantar fasciopathy.
The Physiotherapy Evidence Database (PEDro) scale contains 11 items; items 2–11 receive 1 point each for a yes response. Reliability is sufficient (0.68) for the PEDro scale to be used to assess physiotherapy trials. A score of 6 or higher on the PEDro scale is considered a high-quality study; below 6 is considered a low-quality study. The PEDro score results determined the quality of the randomized controlled trial (RCT), nonrandomized clinical trial, or prospective case series (≥6 or <6). A qualitative analysis was used with 5 levels of evidence (strong, moderate, limited, conflicting, or no evidence) to determine recommendations for the use of the intervention. The number of high-quality or low-quality RCT or nonrandomized clinical trial studies with consistent or inconsistent results determined the level of evidence (1–5).
Main Results:
Using the specific search criteria, the authors identified 418 potential sources. After screening of the title or abstract (or both), they excluded 405 sources, which left 13 studies. After viewing the full text, they excluded 2 additional sources (a case report and a study in which the outcome measure was remission of symptoms and not pain or function), leaving 11 studies for analysis. Six of the 11 studies were characterized by an observational, noncontrolled design; the remaining 5 studies were controlled clinical trials, 2 of which had proper randomization.
The mean number of participants included in the studies was 40.5 (range = 20 to 100). Three of the studies were on “tennis elbow,” 1 on “golfer's elbow,” 1 on wrist extensor or flexor tendinopathy, 3 on plantar fasciopathy, and 3 on chronic patellar tendinopathy. Based on the information reported, there was no standardization of frequency or method of growth factor injection treatment or of preparation of the volume, and an optimal mixture was not described. Autologous whole-blood injections were used in 8 studies; in 5 studies, the autologous whole-blood injection was combined with a local anesthetic. In contrast, a local anesthetic was used in only 1 of the 3 PRP injection studies. The authors of the other 2 studies did not report whether a local anesthetic was used. The number of autologous whole-blood and PRP injections varied, ranging from 1 to 3. The centrifuging process was single or double for the PRP injections. In 2 studies, calcium was added to activate the platelets. A visual analogue or ordinal pain scale was used in 10 of the 11 studies. Function was evaluated in 9 of the 11 studies using (1) the Nirschl scale in 4 elbow studies or the modified Mayo score at baseline in 1 elbow study, (2) the Victorian Institute of Sports Assessment-Patella score for 1 study and the Tegner score for 2 of the patellar tendinopathy studies, and (3) the rearfoot score of the American Orthopaedic Foot and Ankle Scale for 1 plantar fasciopathy study. Only 1 study used an appropriate, disease-specific, validated tendinopathy measure (Victorian Institute of Sports Assessment-Patella).
All intervention groups reported a significant improvement in pain or function score (or both), with a mean improvement of 66% over a mean follow-up of 9.4 months. The control groups in these studies also showed a mean improvement of 57%. None of the pain benefits among the intervention groups were greater than those for the control group at final follow-up. In 4 of the studies, the control group and the autologous growth factor injection group had similar results in pain or function or both, whereas in 2 studies, the control group had greater relief in pain than the injection group.
Eleven studies were assessed using the PEDro scale. The PEDro scores for these studies ranged from 1 to 7, with an average score of 3.4. Only 3 studies had PEDro scores of ≥6 and were considered high quality. The 3 high-quality plantar fasciopathy studies used autologous growth factor injections but did not show a significant improvement over the control group. One of the studies that showed no beneficial effect for the autologous growth factor injections was compared with corticosteroids. Compared with other treatments, level 1 (strong) evidence demonstrated that autologous growth factor injections did not improve pain or function in plantar fasciopathy. The PRP injection results were based on 3 low-quality studies, 2 for the patellar tendon and 1 for the wrist flexors-extensors; level 3 (limited) evidence suggests that PRP injections improve pain or function.
Conclusions:
Strong evidence indicates that autologous growth factor injections do not improve plantar fasciopathy pain or function when combined with anesthetic agents or when compared with corticosteroid injections, dry needling, or exercise therapy treatments. Furthermore, limited evidence suggests that PRP injections are beneficial. Except for 2 high-quality RCT studies, the rest were methodologically flawed. Additional studies should be conducted using proper control groups, randomization, blinding, and validated disability outcome measures for pain and function. Until then, the results remain speculative because autologous whole-blood and PRP injection treatments are not standardized.
doi:10.4085/1062-6050-49.3.06
PMCID: PMC4080590  PMID: 24840581
tendon injuries; platelet-rich plasma; injection therapy
14.  The Effect of Platelet-rich Plasma on Wounds of OLETF Rats Using Expression of Matrix Metalloproteinase-2 and -9 mRNA 
Archives of Plastic Surgery  2012;39(2):106-112.
Background
Complicated diabetic patients show impaired, delayed wound healing caused by multiple factors. A study on wound healing showed that platelet-rich plasma (PRP) was effective in normal tissue regeneration. Nonetheless, there is no evidence that when plateletrich plasma is applied to diabetic wounds, it normalizes the diabetic wound healing process. In this study, we have analyzed matrix metalloproteinase (MMP)-2, MMP-9 expression to investigate the effect of PRP on diabetic wounds.
Methods
Twenty-four-week-old male Otsuka Long-Evans Tokushima Fatty rats were provided by the Tokushima Research Institute. At 50 weeks, wounds were arranged in two sites on the lateral paraspinal areas. Each wound was treated with PRP gel and physiologic saline gauze. To determine the expression of MMP-2, MMP-9, which was chosen as a marker of wound healing, reverse transcription polymerase chain reaction (RT-PCR) was performed and local distribution and expression of MMP-2, MMP-9 was also observed throughout the immunohistochemical staining.
Results
RT-PCR and the immunohistochemical study showed that the levels of MMP-2, MMP-9 mRNA expression in PRP applied tissues were higher than MMP-2, MMP-9 mRNA expression in saline-applied tissues. MMP-9 mRNA expression in wounds of diabetic rats decreased after healing began to occur. But no statistical differences were detected on the basis of body weight or fasting blood glucose levels.
Conclusions
This study could indicate the extracellular matrix-regulating effect observed with PRP. Our results of the acceleration of wound healing events by PRP under hyperglycemic conditions might be a useful clue for future clinical treatment for diabetic wounds.
doi:10.5999/aps.2012.39.2.106
PMCID: PMC3385326  PMID: 22783508
Platelet-rich plasma; Rats, OLETF; Matrix mtalloproteinase-2; Matrix metalloproteinase-9
15.  A new simplified technique for producing platelet-rich plasma: a short technical note 
European Spine Journal  2004;13(Suppl 1):S102-S106.
A possible strategy to promote the wound-healing cascade in both soft and hard tissues is the preparation of an autologous platelet-rich plasma (PRP) to encourage the release of growth factors from activated platelets. In this process, PRP combines the advantage of an autologous fibrin clot that will aid in hemostasis as well as provide growth factors in high concentrations to the site of a tissue defect. The PRP preparation can be used as a biological enhancer in the healing of fractures and lumbar fusions. The local application of growth factors seems to promote initiation and early maturation of bone formation. Autologous bone or bone substitutes can be added to this mixture to increase the volume of grafting material. A simplified technique utilizing a commercially available separation system (GPS—Gravitational Platelet Separation System) is described. This system provides a less costly alternative to other previously described augmentation techniques and also presents a patient-friendly and operator-safe alternative. Further experimental studies of the actual concentrations of the growth factors in the PRP samples are necessary in order to validate the platelet concentration and growth-factor activation by laboratory evidence. In further prospective clinical trials, the safety and efficacy of PRP, in combination with autologous bone or bone graft substitutes, must be evaluated.
doi:10.1007/s00586-004-0715-3
PMCID: PMC3592190  PMID: 15221571
Platelet concentrate; Growth factors; Bone healing; Platelet-rich plasma; GPS
16.  Evaluation of the Effects of Platelet-Rich Plasma (PRP) Therapy Involved in the Healing of Sports-Related Soft Tissue Injuries 
The Iowa Orthopaedic Journal  2012;32:150-163.
Abstract
Musculoskeletal injuries are the most common cause of severe long-term pain and physical disability, and affect hundreds of millions of people around the world. One of the most popular methods used to biologically enhance healing in the fields of orthopaedic surgery and sports medicine includes the use of autologous blood products, namely, platelet rich plasma (PRP). PRP is an autologous concentration of human platelets to supra-physiologic levels. At baseline levels, platelets function as a natural reservoir for growth factors including platelet-derived growth factor (PDGF), epidermal growth factor (EGF), transforming growth factor-beta 1 (TGF-β1), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), hepatocyte growth factor (HGF), and insulin-like growth factor (IGF-I). PRP is commonly used in orthopaedic practice to augment healing in sports-related injuries of skeletal muscle, tendons, and ligaments. Despite its pervasive use, the clinical efficacy of PrP therapy and varying mechanisms of action have yet to be established. Basic science research has revealed that PRP exerts is effects through many downstream events secondary to release of growth factors and other bioactive factors from its alpha granules. These effects may vary depending on the location of injury and the concentration of important growth factors involved in various soft tissue healing responses. This review focuses on the effects of PrP and its associated bioactive factors as elucidated in basic science research. Current findings in PRP basic science research, which have shed light on its proposed mechanisms of action, have opened doors for future areas of PrP research.
PMCID: PMC3565396  PMID: 23576936
17.  PARot – assessing platelet-rich plasma plus arthroscopic subacromial decompression in the treatment of rotator cuff tendinopathy: study protocol for a randomized controlled trial 
Trials  2013;14:167.
Background
Platelet-rich plasma (PRP) is an autologous platelet concentrate. It is prepared by separating the platelet fraction of whole blood from patients and mixing it with an agent to activate the platelets. In a clinical setting, PRP may be reapplied to the patient to improve and hasten the healing of tissue. The therapeutic effect is based on the presence of growth factors stored in the platelets. Current evidence in orthopedics shows that PRP applications can be used to accelerate bone and soft tissue regeneration following tendon injuries and arthroplasty. Outcomes include decreased inflammation, reduced blood loss and post-treatment pain relief. Recent shoulder research indicates there is poor vascularization present in the area around tendinopathies and this possibly prevents full healing capacity post surgery (Am J Sports Med36(6):1171–1178, 2008). Although it is becoming popular in other areas of orthopedics there is little evidence regarding the use of PRP for shoulder pathologies. The application of PRP may help to revascularize the area and consequently promote tendon healing. Such evidence highlights an opportunity to explore the efficacy of PRP use during arthroscopic shoulder surgery for rotator cuff pathologies.
Methods/Design
PARot is a single center, blinded superiority-type randomized controlled trial assessing the clinical outcomes of PRP applications in patients who undergo shoulder surgery for rotator cuff disease. Patients will be randomized to one of the following treatment groups: arthroscopic subacromial decompression surgery or arthroscopic subacromial decompression surgery with application of PRP.
The study will run for 3 years and aims to randomize 40 patients. Recruitment will be for 24 months with final follow-up at 1 year post surgery. The third year will also involve collation and analysis of the data. This study will be funded through the NIHR Biomedical Research Unit at the Oxford University Hospitals NHS Trust.
Trial registration
Current Controlled Trials: ISRCTN10464365
doi:10.1186/1745-6215-14-167
PMCID: PMC3686643  PMID: 23758981
Platelet-rich-plasma; Rotator cuff; Tendinopathies; Surgery; Growth factors
18.  Quiescent platelets stimulate angiogenesis and diabetic wound repair 
The Journal of surgical research  2008;160(1):169-177.
Introduction
Platelets partake in hemostasis, wound healing and tumor growth. Although platelet-rich-plasma (PRP) has been used in surgery for several years, its mechanism of action and application methods are still poorly characterized.
Materials and Methods
A single unit of human platelets obtained by plateletpheresis was diluted in plasma and divided into three equal volumes. One volume was stored at room temperature as fresh platelets (RT), another volume frozen by storage at −80 °C (FZ) and the third volume frozen at −80 °C with 6% DMSO (FZ6). Plasma (PL) was used as control. Using flow cytometry, platelets were tested for platelet glycoprotein GPIb and annexin V binding, as survival and activation markers, respectively. Hemostatic function was assessed by thromboelastometry.
In vivo, platelets were topically applied on 1 cm2, full-thickness wounds on db/db mice (n=10/group) and healing was staged microscopically and macroscopically.
Results
All platelet preparations showed hemostatic ability. RT platelets were GPIb positive (nonactivated-quiescent platelets) and stimulated angiogenesis by 3-fold, and cell proliferation by 4-fold in vivo. FZ platelets were positive for annexin V, indicating activated platelets and, in vivo, increased only wound granulation. FZ6 platelets contained 30% nonactivated-quiescent and 50% activated platelets and stimulated granulation, angiogenesis, cell proliferation and promoted re-epithelialization in vivo.
Conclusions
Platelets showed distinct mechanisms to induce hemostasis and wound healing. Quiescent platelets are required to induced angiogenesis in vivo. Platelets stored at room temperature and frozen with 6% DMSO and stored at −80 °C achieved optimal wound healing in diabetic mice.
doi:10.1016/j.jss.2008.09.010
PMCID: PMC2881478  PMID: 19482315
19.  Platelet-rich plasma preparation for regenerative medicine: optimization and quantification of cytokines and growth factors 
Introduction
Platelet-rich plasma (PRP) is nowadays widely applied in different clinical scenarios, such as orthopedics, ophthalmology and healing therapies, as a growth factor pool for improving tissue regeneration. Studies into its clinical efficiency are not conclusive and one of the main reasons for this is that different PRP preparations are used, eliciting different responses that cannot be compared. Platelet quantification and the growth factor content definition must be defined in order to understand molecular mechanisms behind PRP regenerative strength. Standardization of PRP preparations is thus urgently needed.
Methods
PRP was prepared by centrifugation varying the relative centrifugal force, temperature, and time. Having quantified platelet recovery and yield, the two-step procedure that rendered the highest output was chosen and further analyzed. Cytokine content was determined in different fractions obtained throughout the whole centrifugation procedure.
Results
Our method showed reproducibility when applied to different blood donors. We recovered 46.9 to 69.5% of total initial platelets and the procedure resulted in a 5.4-fold to 7.3-fold increase in platelet concentration (1.4 × 106 to 1.9 × 106 platelets/μl). Platelets were highly purified, because only <0.3% from the initial red blood cells and leukocytes was present in the final PRP preparation. We also quantified growth factors, cytokines and chemokines secreted by the concentrated platelets after activation with calcium and calcium/thrombin. High concentrations of platelet-derived growth factor, endothelial growth factor and transforming growth factor (TGF) were secreted, together with the anti-inflammatory and proinflammatory cytokines interleukin (IL)-4, IL-8, IL-13, IL-17, tumor necrosis factor (TNF)-α and interferon (IFN)-α. No cytokines were secreted before platelet activation. TGF-β3 and IFNγ were not detected in any studied fraction. Clots obtained after platelet coagulation retained a high concentration of several growth factors, including platelet-derived growth factor and TGF.
Conclusions
Our study resulted in a consistent PRP preparation method that yielded a cytokine and growth factor pool from different donors with high reproducibility. These findings support the use of PRP in therapies aiming for tissue regeneration, and its content characterization will allow us to understand and improve the clinical outcomes.
doi:10.1186/scrt218
PMCID: PMC3706762  PMID: 23759113
Platelet-rich plasma; Centrifugation; Growth factors; Cytokine; Activation
20.  Platelet Activation by Collagen Provides Sustained Release of Anabolic Cytokines 
Background
Platelet-rich plasma (PRP) has been increasingly used in sports medicine applications. Platelets are thought to release growth factors important in wound healing, including transforming growth factor (TGF-β1), platelet-derived growth factor (PDGF-AB), and vascular endothelial growth factor (VEGF). However, little is known about the effect of platelet activator choice on growth factor release kinetics.
Hypothesis
The choice of platelet activator would affect the timing and level of growth factor release from PRP.
Study Design
Controlled laboratory study.
Methods
Platelet-rich plasma aliquots were activated with either thrombin or collagen. A control group of whole blood aliquots was clotted with thrombin. Supernatant containing the released growth factors was collected daily for 1 week. Levels of TGF-β1, PDGF-AB, and VEGF were measured using enzyme-linked immunosorbent assay (ELISA).
Results
The use of thrombin as an activator resulted in immediate release of TGF-β1 and PDGF-AB, while the collagen-activated PRP clots released similar amounts each day for 5 days. The use of collagen as an activator resulted in an 80% greater cumulative release of TGF-β1 from the PRP aliquots over 7 days (P < .001). Concentrating platelets to 3 times the systemic blood level resulted in a 3-fold higher release of TGF-β1, 2.5-fold greater release of PDGF, and 5-fold greater release of VEGF (all P < .0001) when compared with whole blood control clots, but no significant differences in the timing of release were noted.
Conclusion
These experiments demonstrated that the choice of platelet activator can significantly influence the release kinetics of cytokines from PRP, with thrombin resulting in an immediate release and collagen having a more sustained release pattern.
Clinical Relevance
The level and rate of growth factor release depends on the selected platelet activator, a factor that should be considered when selecting a PRP system for a given application.
doi:10.1177/0363546511401576
PMCID: PMC3176726  PMID: 21398575
blood clot; growth factor; platelet activation; release kinetics
21.  Double-application of platelet-rich plasma on bone healing in rabbits 
Objective: Platelet-rich plasma (PRP) is considered to enhance bone formation especially at early stages of wound healing, depending on the limited and short life-span of platelets and growth factors. The aim of this study was to evaluate efficacy of double-application of PRP (DA-PRP) on bone healing in a rabbit calvarial defect model. Study design: Twenty-eight rabbits, each had two surgically prepared calvarial bone defects (10mm diameter), were included in this study and randomly divided into six groups. Defects (n=56) were treated with single-application of PRP (SA-PRP)(n=10), SA-PRP and beta-tricalciumphosphate (SA-PRP+TCP)(n=10), DA-PRP (n=8), DA-PRP and beta-tricalciumphosphate (DA-PRP+TCP)(n=8), beta-tricalciumphosphate (TCP)(n=10) or left empty (Control)(n=10). Animals were sacrificed at 30 days postoperatively. Results: The new bone (NB%) and defect fill (DF%) percentages were calculated from histological slides by image-analyzer software and statistically analysed. All test groups showed higher NB% than control, but differences among all groups were insignificant. The TCP treated groups had significantly higher DF% than groups treated without TCP, however the DF% differences between control, SA-PRP and DA-PRP or TCP, SA-PRP+TCP or DA-PRP+TCP were insignificant. Conclusion: Although new bone formation was histomorphologically remarkable at double-application PRP groups, statistical analyses of the histomorphometric data revealed no significant difference.
Key words: Platelet-Rich Plasma, double application, bone formation, wound healing.
doi:10.4317/medoral.17336
PMCID: PMC3448207  PMID: 22157673
22.  Effect of platelet-rich plasma on the healing of cutaneous defects exposed to acute to chronic wounds: a clinico-histopathologic study in rabbits 
Diagnostic Pathology  2015;10:85.
Background
Platelet-rich plasma (PRP) contains numerous growth factors to promote wound healing and angiogenesis. The aim of this study was to gain further information about the benefits of platelet-rich-plasma for healing cutaneous acute to chronic wounds.
Methods
A total of 30 New Zealand albino rabbits (n = 15/group) were randomly assigned to two experimental groups: control group, and PRP group. Bilateral resection defects measuring 3 cm were surgically created on the dorsolateral of the cutaneous in animals and the defects were randomly divided into two mentioned groups. Wound area, neovascularization, size and epithelialization were compared on days 7, 14 and 21 post-wounding. Histopathological analyses were conducted on 15 specimens from each group after sacrifice by the cellular aspects of the regeneration of the tissue.
Results
Our results were indicated that the wound area of PRP was smaller than that in the non-treated group on days 7, 14 and 21. Furthermore, a significant decrease of the wound size was observed in PRP groups that were significantly greater than that in the control group. A significant increase of the mean vascular density was noted in the PRP treated groups compared to the control groups at day 14 and especially day 21. This results indicated that PRP treated group’ enhanced angiogenesis at the wound beds as compared to no treatment group.
Conclusion
These results could be useful for researchers in the growing fields of tissue repair and experimental wound healing. Further studies will be essential to determine the role of PRP in clinical practice.
doi:10.1186/s13000-015-0327-8
PMCID: PMC4487960  PMID: 26134399
Platelet-rich plasma; Histopathology; Wound; Regeneration; Rabbit
23.  Comparison between Conventional Mechanical Fixation and Use of Autologous Platelet Rich Plasma (PRP) in Wound Beds Prior to Resurfacing with Split Thickness Skin Graft 
BACKGROUND
Platelet rich plasma is known for its hemostatic, adhesive and healing properties in view of the multiple growth factors released from the platelets to the site of wound. The primary objective of this study was to use autologous platelet rich plasma (PRP) in wound beds for anchorage of skin grafts instead of conventional methods like sutures, staplers or glue.
METHODS
In a single center based randomized controlled prospective study of nine months duration, 200 patients with wounds were divided into two equal groups. Autologous PRP was applied on wound beds in PRP group and conventional methods like staples/sutures used to anchor the skin grafts in a control group.
RESULTS
Instant graft adherence to wound bed was statistically significant in the PRP group. Time of first post-graft inspection was delayed, and hematoma, graft edema, discharge from graft site, frequency of dressings and duration of stay in plastic surgery unit were significantly less in the PRP group.
CONCLUSION
Autologous PRP ensured instant skin graft adherence to wound bed in comparison to conventional methods of anchorage. Hence, we recommend the use of autologous PRP routinely on wounds prior to resurfacing to ensure the benefits of early healing.
PMCID: PMC4298865  PMID: 25606477
Platelet rich plasma; Hemostasis; Skin graft; Edema
24.  Nanosecond Pulse Electric Field Activated-Platelet Rich Plasma Enhances the Return of Blood Flow to Large and Ischemic Wounds in a Rabbit Model 
Physiological Reports  2015;3(7):e12461.
Platelet-rich plasma is a therapeutic strategy used for accelerating wound healing of a wide range of tissues through the release of platelet growth factors. Here, we describe a nonchemical, safe method for preparing platelet-rich plasma using nanosecond-pulsed electric fields (nsPEFs) and investigated the effect of this platelet-rich plasma on reperfusion of blood in large skin flap or ischemic hind limb wounds in New Zealand White rabbits. Laser Doppler images of blood flow to the dorsal surface of skin flap wounds or to ischemic hind limb wounds were obtained from wounds treated with 0.9% saline or nanosecond-pulsed electric field prepared platelet-rich plasma (nsPRP). Reperfusion in the skin flap wounds was greater in the nsPRP-treated wounds than in the wounds treated with saline on postoperative days 3 (P < 0.001) and 21 (P < 0.03). Reperfusion in the ischemic hind-limb treated with nsPRP was greater than in the saline-treated limb on post-operative Day 3 (P < 0.001), post-operative week 1 (P < 0.025) and post-operative week 4 (P < 0.015). In the hind limb ischemic tissue, the number of endothelial cells, collagen, and cells containing vascular endothelial growth factor (VEGF) was greater in the nsPRP-treated tissue. These results demonstrate that nsPRP improves blood flow in large surgical skin wounds and in ischemic wounds.
doi:10.14814/phy2.12461
PMCID: PMC4552537  PMID: 26197934
Ischemic wound; Nanosecond-pulsed electric field; platelet-rich plasma
25.  Bone Marrow Aspiration Concentrate and Platelet Rich Plasma for Osteochondral Repair in a Porcine Osteochondral Defect Model 
PLoS ONE  2013;8(8):e71602.
Background
Bone marrow aspiration concentrate (BMAC) may possess a high potency for cartilage and osseous defect healing because it contains stem cells and multiple growth factors. Alternatively, platelet rich plasma (PRP), which contains a cocktail of multiple growth factors released from enriched activated thrombocytes may potentially stimulate the mesenchymal stem cells (MSCs) in bone marrow to proliferate and differentiate.
Methods
A critical size osteochondral defect (10×6 mm) in both medial femoral condyles was created in 14 Goettinger mini-pigs. All animals were randomized into the following four groups: biphasic scaffold alone (TRUFIT BGS, Smith & Nephew, USA), scaffold with PRP, scaffold with BMAC and scaffold in combination with BMAC and PRP. After 26 weeks all animals were euthanized and histological slides were cut, stained and evaluated using a histological score and immunohistochemistry.
Results
The thrombocyte number was significantly increased (p = 0.049) in PRP compared to whole blood. In addition the concentration of the measured growth factors in PRP such as BMP-2, BMP-7, VEGF, TGF-β1 and PDGF were significantly increased when compared to whole blood (p<0.05). In the defects of the therapy groups areas of chondrogenic tissue were present, which stained blue with toluidine blue and positively for collagen type II. Adding BMAC or PRP in a biphasic scaffold led to a significant improvement of the histological score compared to the control group, but the combination of BMAC and PRP did not further enhance the histological score.
Conclusions
The clinical application of BMAC or PRP in osteochondral defect healing is attractive because of their autologous origin and cost-effectiveness. Adding either PRP or BMAC to a biphasic scaffold led to a significantly better healing of osteochondral defects compared with the control group. However, the combination of both therapies did not further enhance healing.
doi:10.1371/journal.pone.0071602
PMCID: PMC3741121  PMID: 23951201

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