Therapeutic applications of canine platelets and their derivatives: a narrative review.

Platelets contain a multitude of growth factors and play a crucial role in physiological processes such as thrombogenesis, tissue repair, and angiogenesis. As a result, platelet-derived products have significant potential for efficient utilization in the realm of regenerative medicine due to their therapeutic and biological attributes. Numerous studies have already substantiated the therapeutic viability of platelets in various canine ailments. The existing literature indicates a substantial surge in the clinical application of canine platelets, positioning platelet-derived products as a viable alternative to conventional therapeutic agents. Platelet concentrates, including platelet-rich plasma and platelet-rich fibrin are commonly used as a therapeutic modality in clinical cases. These therapeutic derivatives exhibit effectiveness in tissue regeneration and can serve as complementary therapies. Notably, they offer a cost-effective and easily accessible therapeutic option, which has demonstrated its benefits in chronic inflammatory disorders such as osteoarthritis and tendinitis, ophthalmic conditions, wound healing, and mandibular injuries in canine patients. The broad spectrum of therapeutic effects displayed by platelets is providing researchers with novel perspectives for crafting therapeutic models in future investigations. This review centers on exploring the therapeutic potential of canine platelets across diverse disorders. Further exploration into platelet products, encompassing their preparation and applicability in canine medicine, is imperative. These inquiries hold the promise of unveiling fresh horizons for the domain of regenerative medicine.

Orthobiologic Interventions for Muscle Injuries.

Muscle injuries represent a common problem in active populations. Orthobiologics continue to be studied for their ability to improve muscle healing. To date, the basic science research for treating muscle injuries with platelet-rich plasma or stem cell remains novel. Furthermore, there are even fewer clinical studies on these topics, and their findings are inconclusive. Reviewing the literature, muscle injuries treated with ultrasound-guided leukocyte-rich PRP injections appear to have the strongest evidence. Scar formation remains a major barrier in muscle injury healing, and there is optimism for future orthobiologic treatments that target the downregulation of TGF-B, resulting in decreased scar development.

Effect of intrauterine infusion of platelet-rich plasma for women with recurrent implantation failure: a systematic review and meta-analysis.

This study evaluated the effect of intrauterine perfusion of autologous platelet-rich plasma (PRP) on pregnancy outcomes in women with recurrent implantation failure (RIF). Key biomedical databases were searched to identify relevant clinical trials and observational studies. Outcomes included clinical pregnancy rate, chemical pregnancy rate, implantation rate, live birth rate, and abortion rate. Data was extracted from ten studies (six randomised controlled trials, four cohort studies) involving 1555 patients. Pregnancy outcomes were improved in women treated with PRP compared to controls: clinical pregnancy rate (RR = 1.96, 95% CI [1.67, 2.31], p < 0.00001, I2 = 46%), chemical pregnancy rate (RR = 1.79, 95% CI [1.54, 2.08], p < 0.00001, I2 = 29%), implantation rate (RR = 1.90, CI [1.50, 2.41], p < 0.00001, I2 = 0%), live birth rate (RR = 2.83, CI [1.45, 5.52], p = 0.0007, I2 = 83%), abortion rate (RR = 0.40, 95% CI [0.18, 0.90], p = 0.03, I2 = 59%). These data imply PRP has potential to improve pregnancy outcomes in women with RIF, suggesting a promising role in assisted reproductive technology.IMPACT STATEMENTWhat is already known on this subject? Platelet-rich plasma (PRP) is an autologous blood product that contains platelets, various growth factors, and cytokines at concentrations above the normal baseline level. Recent studies have shown that intrauterine infusion of autologous PRP can improve pregnancy outcomes in infertile women.What do the results of this study add? This systematic review and meta-analysis of data from ten studies (n = 1555; 775 cases and 780 controls) investigated the effect of intrauterine perfusion of autologous PRP on pregnancy outcomes in women with recurrent implantation failure (RIF). Findings suggest that pregnancy outcomes, including clinical pregnancy rate, chemical pregnancy rate, implantation rate, live birth rate and abortion rate were improved in women treated with PRP compared to controls.What are the implications of these findings for clinical practice and/or further research? RIF remains a challenge for researchers, clinicians, and patients. Our study identified PRP as a potential intervention in assisted reproduction. As an autologous blood preparation, PRP eliminates the risk of an immune response and transmission of disease. PRP is low cost and effective and may represent a new approach to the treatment of patients with RIF.

Rejuvenating the periorbital area using platelet-rich plasma: a systematic review and meta-analysis.

Intradermal injection of autologous platelet-rich plasma (PRP) is a non-surgical cosmetic therapy to rejuvenate the periorbital area pathologies of wrinkles, periorbital hyperpigmentation (POH), and photoaging. The past decade has seen the adoption of this novel therapy around the world. This is the first systematic review and meta-analysis evaluating PRP treatment of periorbital pathologies. This is a PRISMA compliant review that includes a comprehensive search of the databases Cochrane Library, Ovid Medline, Ovid Embase, and clinicaltrials.gov. The search was performed in June 2019 to obtain all peer-reviewed articles published in English that describe the application of PRP to periorbital pathologies. A meta-analysis of patient satisfaction was performed for randomized controlled trials. Nineteen studies treating 455 patients (95% female, age range 28-60) were included. Studies were categorized based on reported outcomes: wrinkles (11 studies), POH (7 studies), and photoaging (6 studies). Patients were treated a mean of 3 times (range 1-8) in mean intervals of 23 days (range 14-56 days). Follow-up averaged 3 months (range 1-6 months). Meta-analysis of 3 randomized controlled clinical trials (RCTs) shows that patients treated with PRP have increased satisfaction above controls of saline, platelet-poor plasma, mesotherapy, and as an adjunct to laser therapy (overall effect p = 0.001, heterogeneity I2 = 64%). PRP treatment of periorbital area pathologies results in histologic improvements of photoaging, subjective satisfaction score increases, and blind evaluator assessments of rejuvenated skin appearance. Future studies are needed to address limitations of the current literature and should include long-term follow-up, delineation of the POH etiology that is treated, RCTs with low risk of bias, and be absent conflicts of interest or industry sponsors.Trial registration: Prospero Systematic Review Registration ID: CRD42019135968.

Platelet-Rich Plasma: Evolving Role in Plastic Surgery.

BACKGROUND: The use of platelet-rich plasma has emerged as one of the most desired nonsurgical treatments for facial rejuvenation and hair restoration. It has grown to encompass a wide variety of applications within the field of plastic surgery, including its use in combination with microneedling, laser, and fat-grafting procedures. METHODS: In this article, the authors aim to (1) describe the preparation process of platelet-rich plasma; (2) discuss the proposed science behind platelet-rich plasma with regard to its evolving role in hair restoration and facial rejuvenation; and (3) highlight the recent literature examining its widespread use. RESULTS: Based on the available literature, there is a therapeutic advantage to the use of platelet-rich plasma as a single treatment modality for alopecia and skin rejuvenation and in combination with laser skin treatment and fat grafting. There is, however, a considerable amount of variability in the processing, preparation, and treatment modalities. CONCLUSIONS: Despite a lack of standardized protocols for platelet-rich plasma preparation and a scarcity of large-scale studies with long-term follow-up, there is convincing evidence with objective measurement modalities that display positive outcomes after treatment for skin rejuvenation, hair regrowth, wound healing, and fat graft take.

Effects of intraovarian injection of autologous platelet rich plasma on ovarian reserve and IVF outcome parameters in women with primary ovarian insufficiency.

We aimed to determine whether intraovarian injection of autologous platelet rich plasma (PRP) improves response to ovarian stimulation and in vitro fertilization (IVF) outcome in women with primary ovarian insufficiency (POI). Women (N=311; age 24-40) diagnosed with POI based on ESHRE criteria underwent intraovarian PRP injection. Markers of ovarian reserve, and IVF outcome parameters were followed. PRP treatment resulted in increased antral follicle count (AFC) and serum antimullerian hormone (AMH), while serum follicle stimulating hormone (FSH) did not change significantly. After PRP injection, 23 women (7.4%) conceived spontaneously, 201 (64.8%) developed antral follicle(s) and attempted IVF, and 87 (27.8%) had no antral follicles and therefore did not receive additional treatment. Among the 201 women who attempted IVF, 82 (26.4% of total) developed embryos; 25 of these women preferred to cryopreserve embryos for transfer at a later stage, while 57 underwent embryo transfer resulting in 13 pregnancies (22.8% per transfer, 4% of total). In total, of the 311 women treated with PRP, 25 (8.0%) achieved livebirth/sustained implantation (spontaneously or after IVF), while another 25 (8.0%) cryopreserved embryos. Our findings suggest that in women with POI, intraovarian injection of autologous PRP might be considered as an alternative experimental treatment option.

Positive effects of platelet-rich plasma (PRP) and a Sanguisorba officinalis polysaccharide on the proliferation and differentiation of anterior cruciate ligament (ACL) fibroblasts in vitro.

Context: Sanguisorba officinalis L. (Rosaceae), a famous traditional Chinese medicine. It was recently reported that its polysaccharide could facilitate collagen production.Objectives: We investigated the mechanism by which S. officinalis polysaccharide (SOWPa) and/or platelet-rich plasma (PRP) promote regenerative potential of anterior cruciate ligament (ACL) in vitro.Materials and methods: ACL fibroblasts were treated with SOWPa (25 and 100 mg/kg), PRP, PRP + SOWPa (25 and 100 mg/kg) or vehicle alone for 24, 48, or 72 h. Cell viability, migration ability and apoptosis were evaluated by MTT, transwell and flow cytometry, respectively. Western blot analysis was performed to assess associated protein expression.Results: PRP, SOWPa (100 mg/kg) or PRP + SOWPa (100 mg/kg) treatment for 72 h significantly improved the cell viability of ACL fibroblasts from 100 ± 7.5% (control) to 156.85 ± 12.82%, 188.08 ± 15.92%, and 223.67 ± 18.82%, respectively, which was evidenced by individual decreased apoptosis rate from 31.26 ± 2.35% (control) to 20.80 ± 1.89%, 18.01 ± 1.55% and 9.33 ± 0.78%. Furthermore, the motility of ACL fibroblasts was significantly improved with increased migrated cell number per field from 5 for control to 26 for PRP, 36 for SOWPa and 44 for PRP + SOWPa, respectively. Moreover, the protein expression of differentiation markers (RUNX2, ALP, BMP2 and Col I) and TLR-4 and phosphorylated p65 (p-p65) was inhibited by the above treatment.Discussion and conclusions: Data suggested that the addition of SOWPa to PRP increased the regenerative ability of ACL fibroblasts by blocking the TLR-4/NF-κB pathway.

Update in minimally invasive periorbital rejuvenation with a focus on platelet-rich plasma: A narrative review.

BACKGROUND: The periorbital region is among the first areas to be affected by the process of aging, which is influenced by genetic and constitutional factors. As the region plays an important role in overall facial appearance, rejuvenation of the area has immense cosmetic benefit and various treatment modalities have been used to achieve the same. AIMS: This article reviews commonly used non-surgical and minimally invasive modalities for periorbital rejuvenation. METHODS: The literature research considered published journal articles (clinical trials or scientific reviews). Studies were identified by searching electronic databases (MEDLINE and PubMed) and reference lists of respective articles. Only articles available in English were considered for this review. RESULTS: Autologous platelet rich plasma (PRP) is increasingly used in dermatology for skin and hair conditions. The use of PRP is rapidly growing in popularity as a modality to achieve skin rejuvenation. The mechanism by which PRP leads to skin rejuvenation is by increasing the dermal fibroblast proliferation, expression of matrix metalloproteinase and collagen synthesis. CONCLUSION: The evidence discussed in this article indicates the increasing importance of minimally invasive modalities in periorbital rejuvenation and a promising role for PRP as solo therapy or in multimodality regimens.

Use of autologous platelet-rich plasma in healing skin graft donor sites.

OBJECTIVE: To demonstrate that the use of platelet-rich plasma (PRP) enhances both the quality of healing and the time required for wound healing at a skin graft donor site. METHODS: Patients who had dermo-epidermal skin grafts taken from the thigh area were included in a prospective, randomised clinical study. PRP was applied to one donor site and then covered with Vaseline-impregnated, open-weave gauze and gauze, while the contralateral donor site on the other thigh served as a control and was covered with the open-weave gauze and gauze without PRP. RESULTS: A total of 24 patients took part in the study, of which three developed infections and were thus removed from the study. Use of PRP reduced the wound healing time of the dermo-epidermal graft donor sites by a mean 17.8% and median 18 days. On average, the treated donor sites healed in 14.9 days compared with 18.4 days for the control group. The median was 14 days compared with 18 days in the control group (p=0.026). In one patient, healing was slower on the side where PRP was applied. In 20 patients, healing of the donor site was accelerated where PRP was applied. CONCLUSION: The study demonstrated a beneficial effect of PRP, as healing time was shortened. Using PRP to heal wounds could be beneficial for patients for whom commonly available wound healing therapies have failed, as well as for high-risk patient groups for whom problematic wound healing may be expected.

Effects of Autologous Platelet Rich Plasma on Intraoperative Transfusion and Short-Term Outcomes in Total Arch Replacement (Sun's Procedure): A Prospective, Randomized Trial.

OBJECTIVE: To observe the effect of collecting and retransfusing autologous platelet rich plasma (aPRP) on the amount of allogeneic blood usage in total arch replacement (Sun's surgery) and the outcomes 30 days after surgery. DESIGN: A prospective, randomized trial. SETTING: A tertiary university hospital specialized in cardiovascular diseases. PARTICIPANTS: The study comprised 120 patients undergoing Sun's surgery for Stanford type A acute aortic dissection. INTERVENTIONS: aPRP was harvested before incision and was re-transfused after heparin neutralization for patients in the treatment group. MEASUREMENTS AND MAIN RESULTS: There was no significant difference in preoperative demographic data between the 2 study groups. Intraoperative transfusions of erythrocyte (p = 0.009), plasma (p = 0.017), cryoprecipitate (p = 0.002), and platelets (p < 0.001) in the treatment group were reduced significantly. In addition, less blood loss was observed in the treatment group (p = 0.002). The durations of postoperative mechanical ventilation (p = 0.029) and hospitalization (p = 0.002) of the treatment group were significantly shorter. There were no statistically significant differences in the length of intensive care unit stay, the incidence of complications, and mortality 30 days after surgery. CONCLUSION: In total arch replacement (Sun's surgery), collecting and retransfusing aPRP reduced intraoperative transfusions of erythrocyte, plasma, and cryoprecipitate and decreased the duration of postoperative mechanical ventilation and hospitalization. This technique had no significant effect on the incidence of complications and mortality 30 days postoperatively.

Autologous pure platelet-rich plasma injections for facial skin rejuvenation: Biometric instrumental evaluations and patient-reported outcomes to support antiaging effects.

BACKGROUND: During skin aging, a degeneration of connective tissue and decrease in hyaluronic acid polymers occur. Since platelet-rich plasma (PRP) contains growth factors and various cytokines, it was hypothesized that it could play a role in fibroblast activation and type I collagen expression in human fibroblasts. OBJECTIVES: This study was performed to assess the efficacy of autologous PRP injections for facial skin rejuvenation, measured by biometric instrumental evaluations and patient-reported outcomes. PATIENTS AND METHODS: Patients signed an informed consent form. The EmCyte PurePRP® system technology was used to produce neutrophil-poor PurePRP. The efficacy of the procedures was assessed by biometric parameters, and a patient outcome a self-assessment questionnaire on each visit and at 6-month follow-up. RESULTS: Eleven volunteers were included in the study, receiving 3 PurePRP® treatments. A significant decrease in brown spot counts and area (P < 0.05) was seen after 3 months. Wrinkle count and volume were significantly reduced (P < 0.05 for total wrinkle appearance). Skin firmness parameters were significantly improved. Skin redness was significantly improved after 169 days post-therapy for both the nasolabial and malar areas. A decrease in SLEB thickness was already noted at 2 months after the first injection, with an increase in SLEB density (P < 0.05 for both parameters), without affecting subcutaneous fat thickness. Self-assessment at 6-month follow-up revealed an average satisfaction score of >90%. CONCLUSIONS: A series of 3 PurePRP injections at 6-month follow-up resulted in significant skin rejuvenation as demonstrated by biometric parameters and confirmed by patient self-assessment score.

Histological analysis of the association of low level laser therapy and platelet-rich plasma in regeneration of muscle injury in rats.

OBJECTIVE: Muscle injuries are common, and their treatment requires costs and time off. Platelet rich plasma and low level laser therapy have been shown to be affordable and easy to use. The aim of this study was to evaluate the associated effects of low level laser therapy and platelet rich plasma on the treatment of the soleus muscle injured by strain in rats. METHODS: Thirty-five rats were randomly allocated into five groups: Control (C), Injury Control (IC), injury PRP (IP), injury LLLT (ILT) and injury LLLT and PRP (ILTP). The strain injury was induced in the soleus muscle and the IP group received application of platelet rich plasma immediately after the lesion, while the ILT group received low level laser therapy. After seven days, all animals were euthanized and the soleus muscle removed for further histological analysis. RESULTS: The association of both treatments (ILTP) resulted in better histological aspects than the low level laser therapy and platelet rich plasma alone, when compared with the injury group (IC). The collagen analysis exhibited a significant increase in the ILT group (2.99 SD=1.13) compared to the C (1.88 SD=0.41, p=0.012) and IP (2.04 SD=0.44, p=0.018). CONCLUSION: The association of low level laser therapy with platelet rich plasma produced better results on muscle injury compared to the isolated use of these therapies. Furthermore, none of the treatments could modulate the collagen deposition in relation to injury group.

The Effectiveness of Platelet-Rich Plasma in the Treatment of Tendinopathy: A Meta-analysis of Randomized Controlled Clinical Trials.

BACKGROUND: Tendinopathy is very common in the general population. There are increasing numbers of clinical studies referring to platelet-rich plasma (PRP) and platelet-poor plasma (PPP) as treatments for tendinopathy. PURPOSE: To perform a meta-analysis of the outcomes of the PRP groups by preparation method and injection technique in tendinopathy. To determine the clinical effectiveness of the preparations and to evaluate the effect of controls used in the studies reviewed. STUDY DESIGN: Systematic review and meta-analysis. METHODS: The PubMed, EMBASE, CINAHL, and Medline databases were searched in March 2012, April 2014, and August 2015, and randomized controlled trials using autologous blood, PRP, PPP, or autologous conditioned plasma in tendinopathy with outcome measures of pain and follow-up time of 3 months were included in this review. Trials including surgery, tendon tears, and muscle or ligament injuries were excluded. Study quality was assessed using the Cochrane Collaboration risk-of-bias tool by 2 reviewers. Data were pooled using random-effects meta-analysis. The primary outcome measure was a change in pain intensity. Where more than 1 pain scale was included, a functional score was selected ahead of a visual analog scale score. RESULTS: A total of 18 studies (1066 participants) were included. Eight studies were deemed to be at low risk of bias. The most significant outcomes in the PRP groups were seen in those treated with highly cellular leukocyte-rich PRP (LR-PRP) preparations: GPS kit (standardized mean difference [SMD], 35.75; 95% CI, 28.40-43.10), MyCells kit (SMD, 31.84; 95% CI, 17.56-46.13), Prosys kit (SMD, 42.99; 95% CI, 37.73-48.25), and unspecified LR-PRP (SMD, 34.62; 95% CI, 31.69-37.55). When the LR-PRP system types were grouped, there was a strongly positive effect (SMD, 36.38; 95% CI, 34.00-38.77) when compared with leukocyte-poor PRP (SMD, 26.77; 95% CI, 18.31-35.22). In assessing the control groups, there was no clear difference between different types of control injections: saline (SMD, 14.62; 95% CI, 10.74-18.50), local anesthetic (SMD, 15.00; 95% CI, 7.66-22.34), corticosteroid (SMD, 23.82; 95% CI, 10.74-18.50), or dry needling (SMD, 25.22; 95% CI, 21.27-29.16). CONCLUSION: There is good evidence to support the use of a single injection of LR-PRP under ultrasound guidance in tendinopathy. Both the preparation and intratendinous injection technique of PRP appear to be of great clinical significance.

Analysis of photobiomodulation associated or not with platelet-rich plasma on repair of muscle tissue by Raman spectroscopy.

Treatment of muscle injuries usually results in the interruption of sports practice; thus, studies aimed at accelerating the return to activity, with proper tissue repair, are important. Therefore, this study aimed to evaluate the effects of photobiomodulation (PBM), associated or not with platelet-rich plasma (PRP), on the treatment of muscle injury. Thirty-five animals were used and divided into five groups (n = 7): control (C), control lesion (CL), lesion treated with low-level laser therapy (LLLT) (LLt), lesion treated with PRP (LP), and lesion treated with both techniques, LLLT and PRP (LLtP). Muscle injury was induced by stretching the gastrocnemius muscle, and the animals in the LLtP and LP groups received the application of PRP immediately following the injury. The LLLT was applied daily for 7 days. The animals were euthanized 7 days after the injury. Analysis of the NADH/NAD ratio and collagen was performed by Raman spectroscopy; in addition to which, histological analysis of the gastrocnemius muscle was performed. The LLtP group demonstrated a reduction in the area of injury, regenerating cells and a healthy appearance of muscle fibers. The Raman analyses showed a reduction in the NADH/NAD ratio in the CL group, demonstrating oxidative stress, and the collagen presented a reduction in the CL and LLt groups, when compared with the C group. It is concluded that either PBM or PRP, and the association of both, was able to reduce the oxidative stress promoted by injury and modulate collagen production at the site of the injury. Furthermore, although both treatments individually were effective for repairing the damage caused by muscle injury, the association of both demonstrated a better histological aspect.

Autologous serum and plasma rich in growth factors in ophthalmology: preclinical and clinical studies.

The use of blood derivatives represents an alternative therapeutic approach that is gaining interest in regenerative medicine due to its potential to stimulate and accelerate tissue healing. Autologous serum eye drops and platelet-enriched plasma eye drops are being used in the treatment of different ophthalmological disorders. In this review, we summarize the different blood-derived formulations used in the treatment and care of ocular surface disorders. The biological basis and use of autologous serum and plasma rich in growth factors are deeply evaluated as well as the challenges to be addressed in the future in this new generation of blood-derived therapies.

Effect of autologous platelet concentrates for alveolar socket preservation: a systematic review.

The current literature was reviewed to evaluate the effect of autologous plasma concentrates on the preservation of extraction sockets. A comprehensive literature search was performed from October 2013 to February 2014 in the MEDLINE/PubMed and Cochrane Central Register of Controlled Trials (CENTRAL) databases. Four studies, published between the years 2010 and 2013, met the eligibility criteria and were included in the review. There were 102 extractions (55 tests, 47 controls) in 82 patients. There was considerable heterogeneity between studies with regard to the design, follow-up time, surgical techniques, and method of preparation of plasma concentrates, and therefore the data could not be analyzed quantitatively. The use of plasma concentrates seems to accelerate healing and soft tissue epithelialization in extraction sockets and reduce postoperative pain and discomfort. However, there is no evidence to date to confirm that plasma concentrates improve hard tissue regeneration.

Autologous platelet concentrate for post-extraction socket healing: a systematic review.

BACKGROUND: Autologous platelet concentrates are claimed to enhance hard and soft tissue healing due to the considerable amount of growth factors that are released after application in the surgical site. However, their actual efficacy for improving tissue healing and regeneration in oral surgery applications is controversial. Tooth extraction socket healing represents a proper model to study the effect of autologous platelet-enriched preparations due to the concomitant occurrence of different processes of both hard and soft tissue healing. PURPOSE: To evaluate the efficacy of platelet concentrates for alveolar socket healing after tooth extraction, by conducting a systematic review. MATERIALS AND METHODS: Medline, Embase and Cochrane Central Register of Controlled Trials were searched using a combination of specific search terms. The last electronic search was performed on 15 June, 2014. Manual searching of the relevant journals and of the reference lists of reviews and all identified randomised controlled trials was also performed. Randomised controlled trials evaluating the effect of a platelet concentrate on fresh extraction sockets were included. Further inclusion criteria were that at least 10 patients were treated (at least 5 per group) and there was a minimum follow-up duration of 3 months. Primary outcomes were postoperative complications, patient satisfaction and postoperative discomfort. Secondary outcomes were any clinical, radiographic, histological and histomorphometric variables used to assess hard and soft tissue healing. Assessment of the methodological quality of the trials was made. RESULTS were expressed as fixed-effects models using mean differences for continuous outcomes and risk ratios for dichotomous outcomes, with 95% confidence intervals (CI). RESULTS: The initial search yielded 476 articles. After the screening process, six articles met the inclusion criteria (199 teeth in 156 patients). Three studies were considered at high risk of bias, two at medium risk and one at low risk. A large heterogeneity in study characteristics and outcome variables used to assess hard tissue healing was observed. A meta-analyses of two studies reporting histomorphometric evaluation of bone biopsies at 3 months' follow-up showed greater bone formation when platelet concentrates were used, as compared to control cases (P <0.001; mean difference 20.41%, 95% C.I. 13.29%, 27.52%). Beneficial effects of platelet concentrates were generally but not systematically reported in most studies, in particular when considering the effects on soft tissue healing and the patient's reported postoperative symptoms like pain and swelling, although no meta-analysis could be done for such parameters. CONCLUSIONS: Although the results of the meta-analysis of the present review are suggestive for a positive effect of platelet concentrates on bone formation in post-extraction sockets, due to the limited amount and quality of the available evidence, they need to be cautiously interpreted. A standardisation of the experimental design is necessary for a better understanding of the true effects of the use of platelet concentrates for enhancing post-extraction socket healing.

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

The purpose of this study was to radiographically analyze the effect of autologous platelet rich plasma (PRP) on the healing of fresh frozen bone allograft (FFBA) placed in surgically created resection defects in mandibles of dogs. Bilateral resection defects measuring 1.5 cm × 1 cm were surgically created on the inferior border of the mandible in 10 adult male dogs. The defects were randomly divided into three groups: C, FFBA, and FFBA/PRP. In Group C, the defect was filled by blood clot only. In Group FFBA, the defect was filled with particulate fresh frozen bone allograft. In Group FFBA/PRP, it was filled with particulate fresh frozen bone allograft combined with PRP. At 90 days postoperative, standardized radiographs of the mandibles were obtained and results were quantitatively evaluated. Analysis of digitized radiographs indicated that non-PRP grafts were significantly less dense than the PRP grafts. Group FFBA/PRP also presented a statistically greater mineralized tissue area than Groups C and FFBA. Within the limits of this study, it can be concluded that PRP enhanced the healing of FFBA in resection defects in mandibles of dogs.

Histologic comparison between platelet-rich plasma and blood clot in regenerative endodontic treatment: an animal study.

INTRODUCTION: In regenerative endodontic treatment (RET) for immature permanent tooth, better treatment results could be obtained by applying platelet-rich plasma (PRP) as the scaffold rather than the blood clot. The goal of this study was to compare the histologic differences between using PRP and blood clot in RET. METHODS: Three 6-month-old beagles each carrying 9 premolars with double root canals were randomly assigned to the PRP group, blood clot group, or negative control group. All experimental teeth suffered apical periodontitis, and RET was performed. In the blood clot group, bleeding was induced from the periapical tissues to fill the canal space. In the PRP group, autologous PRP was injected into each root canal. The animals were sacrificed 3 months later. Histologic sections were stained with hematoxylin-eosin. Statistical analysis was performed by the Fisher exact test, with the significance set at 0.05. RESULTS: With the ingrowth of cellular cementumlike tissues, the canal wall was thickened, and the apical apex was closed in both the PRP and blood clot groups. Cementocytelike cells were present in the newly formed tissues. Meanwhile, no statistical difference was found in both experimental groups for the average percentage of apical closure, new tissue formation, and pulplike tissue formation. Noticeably, a large number of inflammatory cells were present in some root canals in both groups although the postoperative radiograph revealed the disappearance of periapical radiolucency. CONCLUSIONS: PRP application could be an option for clinical cases in which little or no bleeding were found when irritating the apical tissue during RET.