Effect of platelet-rich plasma on bone healing of fresh frozen bone allograft in mandibular defects: a histomorphometric study in dogs

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Platelet-Rich Plasma, Low-Level Laser Therapy, or Their Combination Promotes Periodontal Regeneration in Fenestration Defects: A Preliminary In Vivo Study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of platelet-rich plasma on the healing of mandibular defects treated with fresh frozen bone allograft: a radiographic study in dogs

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Platelet-Rich Plasma Derived From Bone Marrow Aspirate Promotes New Cementum Formation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Treatment of osteochondral injuries with platelet gel

OBJECTIVES: Treatments for injured articular cartilage have not advanced to the point that efficient regeneration is possible. However, there has been an increase in the use of platelet-rich plasma for the treatment of several orthopedic disorders, including chondral injuries. Our hypothesis is that the treatment of chondral injuries with platelet gel results in higher-quality repair tissue after 180 days compared with chondral injuries not treated with gel.METHODS: A controlled experimental laboratory study was performed on 30 male rabbits to evaluate osteochondral injury repair after treatment with or without platelet gel. Osteochondral injuries were surgically induced in both knees of each rabbit at the medial femoral condyle. The left knee injury was filled with the platelet gel, and the right knee was not treated. Microscopic analysis of both knee samples was performed after 180 days using a histological grading scale.RESULTS: The only histological evaluation criterion that was not significantly different between treatments was metachromasia. The group that was treated with platelet gel exhibited superior results in all other criteria (cell morphology, surface regularity, chondral thickness and repair tissue integration) and in the total score.CONCLUSION: The repair tissue was histologically superior after 180 days in the study group treated with platelet gel compared with the group of untreated injuries.

Effect of platelet-rich plasma on healing of class III furcation defects treated with autogenous bone grafting and guided tissue regeneration: a histomorphometric study in dogs

The purpose of this study was to evaluate the effects of the platelet-rich plasma (PRP) when used in combination with autogenous bone graft and bioabsorbable membrane (Resolut® ) in the treatment of Class  III furcation defects in dogs. Material and method: Class III furcation defects (5 mm in height and in depth) were surgically created in the mandibular third premolars of five mongrel dogs. After nine weeks, the lesions were treated with scaling and root planning and each defect received one of the following treatments: autogenous bone graft + membrane (group C) or PRP + autogenous bone graft + membrane (group T). After a healing period of 90 days, the animals were sacrificed. Routine histological processing and staining with hematoxilyn and eosin and Masson trichrome were performed and a histomorphometric analysis determined the effect of the treatments on periodontal tissue regereneration. Data were analyzed by Hotelling’s T-squared (p < 0.05). Result: No statistically significant difference between C and T groups was observed by the histomorphometric analysis of the furcation area. Both treatment groups demonstrated similar regenerative results with the furcation defects partially filled and periodontal regeneration limited to the experimental notches of the lesions. (p > 0.05). Conclusion: According to the present results, PRP does not enhance the periodontal regeneration in class III furcation defects treated with autogenous bone graft and bioabsorbable membrane.

Platelet-rich plasma (PRP): methodological aspects and clinical applications

The clinical use of platelet-rich plasma (PRP) is based on the increase in the concentration of growth factors and in the secretion of proteins which are able to maximize the healing process at the cellular level. Since PRP is an autologous biologic material, it involves a minimum risk of immune reactions and transmission of infectious and contagious diseases, and it has been widely used for the recovery of musculoskeletal lesions. Despite the great potential for applicability, the implementation of the therapeutic employment of PRP as a clinical alternative has become difficult, due to the lack of studies related to the standardization of the techniques and/or insufficient description of the adopted procedures. Therefore, it is required establish standard criteria to be followed for obtaining a PRP of high quality, as well as a larger number of studies which should establish the proper concentration of platelets for the different clinical conditions. In this context, the purpose of this review is to discuss some methodological aspects used for achieving the PRP, as well as to discuss the bioactive properties of PRP, and to point out its therapeutic use in different fields of regenerative medicine.

Effectiveness of two methods for preparation of autologous platelet-rich plasma: an experimental study in rabbits

The purpose of this study was to compare the quantity and quality of platelets in platelet-rich plasma (PRP) samples prepared using either the single- or the double-centrifugation protocol. Ten adult white New Zealand rabbits were used. Ten ml of blood were drawn from each animal via cardiac puncture. Each blood sample was divided into two equal parts for PRP preparation: 5 ml of blood were centrifuged according to a single-centrifugation protocol (Group I), and 5 ml were centrifuged according to a double-centrifugation protocol (Group II). Manual platelet counts were performed on the whole blood and PRP samples of each group. Smears were also done on all samples in order to see the morphology of the platelets. The data obtained in the manual platelet count were submitted to statistical analysis (repeated measures ANOVA, Tukey, P<.05). The average whole blood platelet count was 446,389/μl. The PRP samples in Group II presented an average platelet amount significantly higher than that of Group I (1,986,875 ± 685,020/μl and 781,875 ± 217,693/μl, respectively). The PRP smears from Group II were the only one to present platelets with altered morphology (75% of the smears). A few lymphocytes with increased cytoplasm were observed in the PRP smears of both Groups I (25% of the smears) and II (62.5% of the smears). Within the limits of this study, it can be concluded that the double-centrifugation protocol resulted in higher platelet concentrations than did the single-centrifugation protocol. However, the double-centrifugation protocol caused alterations in platelet morphology and was more sensitive to small processing errors.

Human Platelet Polymorphism can be a genetic marker associated with HIV/HCV coinfection

To evaluate the associations of HPA polymorphisms -1, -3, and -5 with HIV/HCV coinfection were included in this study 60 HIV/HCV-coinfected patients from the Sao Paulo State health service centers. Data reported by Verdichio-Moraes et al. (2009: J. Med Virol 81:757-759) were used as the non-infected and HCV monoinfected groups. Human Platelet Polymorphism genotyping was performed in 60 Patients co-infected with HIV/HCV by PCR-SSP or PCR-RFLP. HIV subtyping and HCV genotyping was performed by RT-PCR followed sequencing. The data analyses were performed using the χ2 test or Fisher's Exact Test and the logistic regression model. Patients coinfected with HIV/HCV presented HCV either genotype 1 (78.3%) or non-1 (21.7%) and HIV either subtype B (85.0%) or non-B (15%). The Human Platelet Polymorphism-1a/1b genotype was more frequent (P < 0.05) in HIV/HCV coinfection than in HCV monoinfection and the allelic frequency of Human Platelet Polymorphism-5b in the Patients coinfected with HIV/HCV was higher (P < 0.05) than in HCV monoinfected cases and non-infected individuals. These data suggest that the presence of specific HPA allele on platelets could favor the existence of coinfection. On the other hand, Human Platelet Polymorphism-5a/5b was more frequent (P < 0.05) in HIV/HCV coinfected and HCV monoinfected groups than in the non-infected individuals, suggesting that this platelet genotype is related to HCV infection, regardless of HIV presence. Results suggest that the Human Platelet Polymorphism profile in HIV/HCV coinfected individuals differs from the one of both HCV monoinfected and non-infected population. So, the Human Platelet Polymorphism can be a genetic marker associated with HIV/HCV coinfection.

Platelet-rich plasma (PRP) applied during total knee arthroplasty

To evaluate the efficacy of platelet-rich plasma regarding healing, pain and hemostasis after total knee arthroplasty, by means of a blinded randomized controlled and blinded clinical study. Forty patients who were going to undergo implantation of a total knee prosthesis were selected and randomized. In 20 of these patients, platelet-rich plasma was applied before the joint capsule was closed. The hemoglobin (mg/dL) and hematocrit (%) levels were assayed before the operation and 24 and 48 h afterwards. The Womac questionnaire and a verbal pain scale were applied and knee range of motion measurements were made up to the second postoperative month. The statistical analysis compared the results with the aim of determining whether there were any differences between the groups at each of the evaluation times. The hemoglobin (mg/dL) and hematocrit (%) measurements made before the operation and 24 and 48 h afterwards did not show any significant differences between the groups (p > 0.05). The Womac questionnaire and the range of motion measured before the operation and up to the first two months also did not show any statistical differences between the groups (p > 0.05). The pain evaluation using the verbal scale showed that there was an advantage for the group that received platelet-rich plasma, 24 h, 48 h, one week, three weeks and two months after the operation (p < 0.05). In the manner in which the platelet-rich plasma was used, it was not shown to be effective for reducing bleeding or improving knee function after arthroplasty, in comparison with the controls. There was an advantage on the postoperative verbal pain scale.

Osteogenic potential of mesenchymal cells derived from canine umbilical cord matrix co-cultured with platelet-rich plasma and demineralized bone matrix

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Homogenous demineralized dentin matrix and platelet-rich plasma for bone tissue engineering in cranioplasty of diabetic rabbits: biochemical, radiographic, and histological analysis

This study evaluated the effects of homogenous demineralized dentin matrix (HDDM) slices and platelet-rich plasma (PRP) in surgical defects created in the parietal bones of alloxan-induced diabetic rabbits, treated with a guided bone regeneration technique. Biochemical, radiographic, and histological analyses were performed. Sixty adult New Zealand rabbits were divided into five groups of 12: normoglycaemic (control, C), diabetic (D), diabetic with a PTFE membrane (DM), diabetic with a PTFE membrane and HDDM slices (DM-HDDM), and diabetic with PTFE membrane and PRP (DM-PRP). The quantity and quality of bone mass was greatest in the DM-HDDM group (respective radiographic and histological analyses: at 15 days, 71.70±16.50 and 50.80±1.52; 30 days, 62.73±16.51 and 54.20±1.23; 60 days, 63.03±11.04 and 59.91±3.32; 90 days, 103.60±24.86 and 78.99±1.34), followed by the DM-PRP group (respective radiographic and histological analyses: at 15 days 23.00±2.74 and 20.66±7.45; 30 days 31.92±6.06 and 25.31±5.59; 60 days 25.29±16.30 and 46.73±2.07; 90 days 38.10±14.04 and 53.38±9.20). PRP greatly enhanced vascularization during the bone repair process. Abnormal calcium metabolism was statistically significant in the DM-PRP group (P<0.001) for all four time intervals studied, especially when compared to the DM-HDDM group. Alkaline phosphatase activity was significantly higher in the DM-HDDM group (P<0.001) in comparison to the C, D, and DM-PRP groups, confirming the findings of intense osteoblastic activity and increased bone mineralization. Thus, HDDM promoted superior bone architectural microstructure in bone defects in diabetic rabbits due to its effective osteoinductive and osteoconductive activity, whereas PRP stimulated angiogenesis and red bone marrow formation.

Analysis of experimental tendinitis in rats treated with laser and platelet-rich plasma therapies by Raman spectroscopy and histometry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thrombocytopenia and platelet hypoaggregation induced by Bothrops asper snake venom Toxins involved and their contribution to metalloproteinase-induced pulmonary hemorrhage

Thrombocytopenia and platelet dysfunction occur in patients bitten by Bothrops sp snakes in Latin America. An experimental model was developed in mice to study the effects of B. asper venom in platelet numbers and function. Intravenous administration of this venom induces rapid and prominent thrombocytopenia and ex vivo platelet hypoaggregation. The drop in platelet numbers was primarily due to aspercetin, a protein of the C-type lectin family which induces von Willebrand factor-mediated platelet aggregation/agglutination. In addition, the effect of class P-III hemorrhagic metalloproteinases on the microvessel wall also contributes to thrombocytopenia since jararhagin, a P-III metalloproteinase, reduced platelet counts. Hypoaggregation was associated with the action of procoagulant and defibrin(ogen)ating proteinases jararacussin-1 (a thrombin-like serine proteinase) and basparin A (a prothrombin activating metalloproteinase). At the doses which induced hypoaggregation, these enzymes caused defibrin(ogen)ation, increments in fibrin(ogen) degradation products and D-dimer and prolongation of the bleeding time. Incubation of B. asper venom with batimastat and α 2-macroglobulin abrogated the hypoaggregating activity, confirming the role of venom proteinases in this effect. Neither aspercetin nor the defibrin(ogen)ating and hypoaggregating components induced hemorrhage upon intravenous injection. However, aspercetin, but not the thrombin-like or the prothrombin-activating proteinases, potentiated the hemorrhagic activity of two hemorrhagic metalloproteinases in the lungs. © 2005 Schattauer GmbH, Stuttgart.