Evaluating the Effects on Ultrasound and on Magnetic Resonance for Knee Osteoarthritis Treatment by Platelet Rich Plasma Therapy in Combination with Mesenchymal Stem Cells from Autologous Adipose Tissue

Aim: To evaluate the effects based the changes on ultrasound and on magnetic resonance for knee osteoarthritis treatment by platelet-rich plasma therapy in combination with mesenchymal stem cell from autologous adipose tissue. Objects and Methods: 30 patients, 26 females, 4 males, mean age 58.63 ± 11.11, mean disease duration 5.3 ± 4.6 years, respectively 60 knee joints were diagnosed with osteoarthritis at stage II - III according to the Kellgren and Lawrence classifications. After ultrasound and magnetic resonance imaging in the first time, all patients were injected with platelet-rich plasma combined with mesenchymal stem cells from autologous adipose tissue into both knee joints. Results: After treatment 12 months by platelet-rich plasma injection combined with mesenchymal stem cells from autologous adipose tissue: The thickness of articular cartilage on ultrasound increased significantly from 2.08 ± 0.36 mm to 2.48 ± 0.36 mm with p Conclusion: The treatment of knee osteoarthritis by platelet-rich plasma combined with mesenchymal stem cells from autologous adipose tissue was effective in improving cartilage thickness on ultrasound and magnetic resonance, thereby improving the motor function of the knee joint.

Combined administration of platelet rich plasma and autologous bone marrow aspirate concentrate for spinal cord injury: a descriptive case series

Administration of platelet rich plasma(PRP) and bone marrow aspirate concentrate(BMAC) has shown some promise in the treatment of neurological conditions;however, there is limited information on combined administration. As such, the purpose of this study was to assess safety and functional outcomes for patients administered combined autologous PRP and BMAC for spinal cord injury(SCI). This retrospective case series included seven patients who received combined treatment of autologous PRP and BMAC via intravenous and intrathecal administration as salvage therapy for SCI. Patients were reviewed for adverse reactions and clinical outcomes using the Oswestry Disability Index(ODI) for up to 1 year, as permitted by availability of follow-up data. Injury levels ranged from C3 through T11, and elapsed time between injury and salvage therapy ranged from 2.4 months to 6.2 years. Post-procedure complications were mild and rare, consisting only of self-limited headache and subjective memory impairment in one patient. Four patients experienced severe disability prior to PRP combined with BMAC injection, as evidenced by high(> 48/100) Oswestry Disability Index scores. Longitudinal Oswestry Disability Index scores for two patients with incomplete SCI at C6 and C7, both of whom had cervical spine injuries, demonstrated a decrease of 28–40% following salvage therapy, representing an improvement from severe to minimal disability. In conclusion, intrathecal/intravenous co-administration of PRP and BMAC resulted in no significant complications and may have had some clinical benefits. Larger clinical studies are needed to further test this method of treatment for patients with SCI who otherwise have limited meaningful treatment options. This study was reviewed and approved by the Ohio Health Institutional Review Board(IRB No. 1204946) on May 16, 2018.

Single dose of intra-muscular platelet rich plasma reverses the increase in plasma iron levels in exercise-induced muscle damage:A pilot study

Background:Platelet rich plasma(PRP) therapy is widely used in enhancing the recovery of skeletal muscle from injury.However,the impact of intramuscular delivery of PRP on hematologic and biochemical responses has not been fully elucidated in exercise-induced muscle damage.The purpose of this investigation the effects of intramuscular delivery of PRP on hematologic and biochemical responses and recovery strategy muscle damage induced by high intensity muscle exercise(exercise-induced muscle damage,EIMD).Methods:Moderately active male volunteers participated in this study and were assigned to a control group(control,n = 6) and PRP administration group(PRP,n = 6).The subjects performed exercise with a load of 80% one repetition maximum(1RM) maximal voluntary contraction of the elbow flexors until point of exhaustion of the non-dominant arm was reached.The arms were treated with saline or autologous PRP post-24 h EIMD.Venous blood samples were obtained in the morning to establish a baseline value and 1–4 days post-exercise and were analyzed for serum ferritin,iron,iron binding capacity(IBC),creatinine kinase(CK),lactate dehydrogenase(LDH),aspartate aminotransferase(AST),and alanine aminotransferase(ALT).Results:The baseline levels of plasma iron,ferritin,IBC,CK,LDH,AST,and ALT were similar in both the control and PRP groups.However,24-h following exercise a significant increase in these parameters was observed in both groups between 1 and 4 days during the recovery period.Interestingly,PRP administration decreased plasma iron levels compared to the control on the second day post-exercise.Plasma IBC increased in PRP group from Days 2 to 4 post-exercise compared to the control group whilst PRP administration had no effect on plasma ferritin,CK,AST,ALT,or LDH.Conclusion:Acute exhaustive exercise increased muscle damage markers,including plasma iron,IBC,and ferritin levels,indicating muscle damage induced by exercise.PRP administration improves inflammation by reversing the increase in the iron levels post-exercise without displaying any myotoxicity and may have a role to play in the recovery of exercise-induced muscle damage.

Platelet rich plasma(PRP)induces autophagy in osteoblast precursor 3T3-L1

Autophagy is an essential cellular homeostatic mechanism by which intracellular components are delivered into the lysosomes for degradation and recycling.Autophagy has been related with a diversity of pathological or physiological dentary processes such as bone remodeling,skeletal aging,osteoclastogenesis,osteoblastogenesis and different types of oral cancer.Platelet-rich plasma(PRP),isolated from autologous blood,is a plasma preparation containing a higher concentration of platelets which contains numerous different growth factors and cytokines that activate several cellular signaling cascades.The purpose of this study is to investigate the effect of PRP on autophagy stimulation in both osteoblast precursor 3T3-L1 and non-related osteoblastic cells.Our results showed that PRP can increase the number of autophagic structures in 3T3-L1 and HeLa(cervical cancer cells)cells.Moreover,we have determined by Western blot a rise in the lipidated form of the autophagic protein LC3(i.e.LC3-II)upon PRP treatment.Taken together,our results suggest that PRP is able to induce a strongly autophagy response in osteoblast precursor and,to a lesser extent,in non-related osteoblastic cells,suggesting that PRP could be a potential therapeutic tool for some autophagy-related diseases associated with bone homeostasis.

Research progress in the treatment of diabetic foot ulcer with platelet rich plasma

Diabetic foot ulcer,as a common complication of diabetes,is a difficult problem in clinical practice.As a new therapeutic method,platelet rich plasma has the functions of anti-inflammatory,bacteriostasis,microcirculation reconstruction,cell proliferation and differentiation,cell apoptosis reduction,peripheral nerve repair and so on.It can promote tissue repair and ulcer healing at every stage of diabetic foot ulcer.This article reviews the preparation of platelet rich plasma,the mechanism of action,the treatment of diabetic foot ulcer,the existing problems and the future development.

Platelet rich plasma effectiveness in bowel anastomoses:A systematic review

BACKGROUND Anastomotic leak constitutes a major problem in abdominal surgery.Technical insufficiency,topical or systemic factors contribute to disrupted healing of the performed bowel anastomosis and result in anastomosis leakage,with detrimental effects on patient postoperative outcomes.Despite the investigation of several factors and the invention of protective materials,the ideal agent to prevent anastomotic leaks is yet to be determined.AIM To study the effect of platelet rich plasma(PRP)on the healing of bowel anastomoses.METHODS A systematic literature search was performed in PubMed,EMBASE,and Scopus databases to identify studies investigating the effect of PRP application on bowel anastomosis.RESULTS Eighteen studies were eligible with a total population of 712 animals including rats(14 studies),rabbits(2 studies)and pigs(2 studies).No postoperative complications were reported following PRP application.Fourteen out of 18 studies reported a statistically significant higher anastomosis bursting pressure in PRP groups compared to control either in healthy animals or animal models with underlying condition or intervention,such as intraperitoneal chemotherapy or peritonitis.Similar results were reported by ten studies in terms of tissue hydroxyproline levels.One study reported significant increase in collagen deposition in PRP groups.PRP application resulted in significantly decreased inflammatory cell infiltration in the presence of peritonitis or intraperitoneal chemotherapy(6 studies).CONCLUSION The application of PRP is associated with improved bowel anastomosis outcomes,especially in animal models having an underlying condition affecting the normal healing process.PRP application seems to augment the normal healing process under these circumstances.However,further studies are needed to investigate the potential role of PRP on bowel anastomosis healing,especially in clinical settings.

Carboxytherapy and Platelet Rich Plasma： A New Therapy for Trigonitis, Abacterial and Interstitial Cystitis

Cystitis often appears even in absence of bacteria colonization. Trigonitis and interstitial inflammation are the most common morphological features of abacterial cystitis in young and post menopausal women. Arterial obstructive disease and bladder ischemia might play an important role in bladder dysfunction. Activated inflammatory cells produce ROS （radicals of oxygen）, NF kB seems involved in ROS synthesis. Clinical studies have indicated that high CO2 levels can impact upon peripheral tissue, reducing ischaemia, responsible of recurrent inflammation and consequently reducing oxydative phenomena. PRP （platelet-rich plasma） is a volume of fractionated plasma from the patient＇s own blood that contains platelet concentrate rich of alpha granules. PRP interacts tissue repair mechanisms by placing supra-physiological concentrations of autologous platelets at the site of tissue damage. This study proposes a single PRP transvaginal injection followed by 10 weekly applications of carboxytherapy, using subcutaneous injections of sterile CO2 gas. We have selected 6 Women （50-75 years）, affected by recurrent abacterial cystitis with Pain and urge incontinence. All patients showed a subjective sensible reduction of symptoms. After 2 months all patients have neither inflammatory symptoms nor endoscopic evidence of trigonitis. Preliminary qualitative results could encourage the use of carboxytherapy and PRP in treatment of abacterial and interstitial cystitis.

Intraarticular injections(corticosteroid, hyaluronic acid, platelet rich plasma) for the knee osteoarthritis

Osteoarthritis(OA)is a complex"whole joint"disease pursued by inflammatory mediators,rather than purely a process of"wear and tear".Besides cartilage degradation,synovitis,subchondral bone remodeling,degeneration of ligaments and menisci,and hypertrophy of the joint capsule take parts in the pathogenesis.Pain is the hallmark symptom of OA,but the extent to which structural pathology in OA contributes to the pain experience is still not well known.For the knee OA,intraarticular(IA)injection(corticosteroids,viscosupplements,blood-derived products)is preferred as the last nonoperative modality,if the other conservative treatment modalities are ineffective.IA corticosteroid injections provide short term reduction in OA pain and can be considered as an adjunct to core treatment for the relief of moderate to severe pain in people with OA.IA hyaluronic acid(HA)injections might have efficacy and might provide pain reduction in mild OA of knee up to 24 wk.But for HA injections,the costeffectiveness is an important concern that patients must be informed about the efficacy of these preparations.Although more high-quality evidence is needed,recent studies indicate that IA platelet rich plasma injections are promising for relieving pain,improving knee function and quality of life,especially in younger patients,and in mild OA cases.The current literature and our experience indicate that IA injections are safe and have positive effects for patient satisfaction.But,there is no data that any of the IA injections will cause osteophytes to regress or cartilage and meniscus to regenerate in patients with substantial and irreversible bone and cartilage damage.

Use of Platelet Rich Plasma (PRP) in the Treatment of Acute Post Intubation Tracheal Rupture: Report of Two Cases

The use of PRP involves a complex network of molecular events which accelerate tissue regenera-tion due to its richness in growth factors plus a variety of biologic mediators. Several communica-tions tell us about its usefulness on the dental implantology field, plastic surgery, orthopedics and peripheral nerve regeneration after trauma. We have presented our successful experience of its use in pneumology when treating severe hemoptysis, respiratory fistulae, spontaneous pneumothorax and one tracheal rupture. In this article we present two cases of post intubation tracheal rupture successfully treated with the local instillation of PRP on one of them and with the injection of PRP along the lips of the tracheal wound on the other. Tracheal rupture is a rare but life threatening complication of emergency intubation requiring an effective response in order to avoid the risk of patient death due to secondary mediastinitis and sepsis. Up to now there is no general consensus in the treatment of this condition and alternatives in use are not universally accepted. The use of local autologous PRP in our experience has demonstrated a favorable performance in such cases, turning it in a highly promising tool for the treatment of conditions such as this, in which a rapidly effective and minimally invasive handling is required.

An Experimental Study on the Effects of Platelet Rich Plasma on the Wound Healing of Tooth Extraction-Related Bone Defects

Platelet-rich plasma (PRP) has been used as a therapeutic tool to promote wound healing, in orthopedics, dermatology, oral surgery, etc. However, the mechanisms underlying the wound healing effects of PRP remain unclear. The purpose of this study was to evaluate the effectiveness of applying PRP, particularly in the management of tooth extraction sockets. Three upper molars of Fischer rats were extracted, and blood was drawn from the hearts of other rats to prepare PRP. The PRP was activated and applied to the bone defects of the experimental group, and nothing was applied to the bone defects of the control group. On day 3, fibrin network and granulation tissue, which are abundant in blood capillaries, were seen under the PRP layer in the experimental group. On the other hand, only inflammatory cells and a fibrin network were observed in the bone defects of the control group. On day 7, granulation tissue was seen in the bone defects in both the control group and experimental group, although excavation of granulation tissue was noted in the control group. The results demonstrated the presence of a rich fibrin network and early inflammatory reactions in the experimental group, which may lead to rise of thick, vessel-rich granulation tissue. The application of PRP may stimulate wound healing in tooth extraction bone defects, and PRP may confer some beneficial effects on the outcomes.

Nanofat and Platelet Rich Plasma to Enhance Recovery and Minimize Risk of Recurrence after Endoscopic Carpal Tunnel Release

Carpal tunnel release is one of the most common and surgery procedures performed. Complications and recurrence of the condition can occur up to 20% of cases. We describe a technique of utilizing the nanofat and platelet rich plasma to successfully enhance healing and minimize risk of recurrence after endoscopic carpal tunnel release. This patient had exceptionally fast recovery, resuming work in one day and excellent grip strength and a full functioning level at his two-week follow-up. After one year he continues to demonstrate a complete resolution of symptoms and full function without any evidence of recurrence or complications.

Clinical and Magnetic Resonance Image Changes of Platelet-Rich Plasma Therapy in Combination with Human Mesenchymal Stem Cells from Autologous Adipose Tissue for Knee Osteoarthritis Treatment

Objective: To evaluate the efficacy based on clinical symptom and on magnetic resonance image of platelet-rich plasma therapy in combination with mesenchymal stem cells from autologous adipose tissue for knee osteoarthritis treatment. Patients and Method: 30 patients including 26 females and 4 males;correspondingly, 60 knee joints were diagnosed with osteoarthritis with stages II - III of Kellgren and Lawrence, their mean age was 58.63 ± 11.11. All were injected with autologous platelet-rich plasma that was extracted by PRP set, APC 30 PRP PRCEDURE PRAK and autologously extracted mesenchymal stem cells from abdominal adipose tissue using the ADI-25-01 ADIPOSEPRCEDURE PRAK of USA. Results: After 12 months: the pain level according to VAS score at the right knee joint was decreased from 6.0 ± 1.28 before treatment to 1.9 ± 0.3;VAS score at the left knee joint was decreased from 6.43 ± 1.19 to 2.25 ± 0.43. Total Lequene score at right knee joint was decreased from 16.04 ± 1.57 before treatment to 4.31 ± 1.04, at left knee joint was decreased from 17.52 ± 1.74 before treatment to 5.15 ± 1.48. Total WOMAC score at right knee joint was decreased from 55.93 ± 5.56 to 10.37 ± 1.56;at left knee joint was decreased from 53.97 ± 5.57 to 10.07 ± 1.59. There were 86.77% joints with cartilage thickness change and the patellar cartilage thickness was increased from 1.56 ± 0.09 mm before treatment to 1.65 ± 0.09 mm. Conclusion: The treatment of knee osteoarthritis by platelet-rich plasma therapyin combination with mesenchymal stem cells from autologous adipose tissue is effective in reducing pain, improving patient's mobility and walking function, reforming articular cartilage thickness on magnetic resonance image.

Platelet rich fibrin is not a barrier membrane!Or is it?

Platelet-rich fibrin(PRF)is widely used in dentistry and other fields of medicine,and its use has become popular in dental implantology.In several published studies,PRF has been used as a barrier membrane.A barrier membrane is a sheet of a certain material that acts as a biological and mechanical barrier against the invasion of cells that are not involved in bone formation,such as epithelial cells.Among the basic requirements of a'barrier membrane,occlusivity,stiffness,and space maintenance are the criteria that PRF primarily lacks;therefore,it does not fall under the category of barrier membranes.However,there is evidence that PRF membranes are useful in significantly improving wound healing.Does the PRF membrane act as a barrier?Should we think of adding or subtracting some points from the ideal requirements of a barrier membrane,or should we coin a new term or concept for PRF that will incorporate some features of a barrier membrane and be a combination of tissue engineering and biotechnology?This review is aimed at answering the basic question of whether the PRF membrane should be considered a barrier membrane or whether it is something more beyond the boundaries of a barrier membrane.

The effect of platelet-rich plasma on cavernous nerve regeneration in a rat model

The aim of this study was to investigate the effect of platelet-rich plasma(PRP)on cavernous nerve(CN)regeneration and functional status in a nerve-crush rat model.Twenty-four Sprague-Dawley male rats were randomly divided into three equal groups:eight had a sham operation,eight underwent bilateral nerve crushing with no further intervention and eight underwent bilateral nerve crushing with an immediate application of PRP on the site of injury.Erectile function was assessed by CN electrostimulation at 3 months and nerve regeneration was assessed by toluidine blue staining of CN and nicotinamide adenine dinucleotide phosphate(NADPH)-diaphorase staining of penile tissue.Three months after surgery,in the group that underwent bilateral nerve crushing with no further intervention,the functional evaluation showed a lower mean maximal intracavernous pressure(ICP)and maximal ICP per mean arterial pressure(MAP)with CN stimulation than those in the sham group.In the group with an immediate application of PRP,the mean maximal ICP and maximal ICP/MAP were significantly higher than those in the injured control group.Histologically,the group with the application of PRP had more myelinated axons of CNs and more NADPH-diaphorase-positive nerve fibres than the injured control group but fewer than the sham group.These results show that the application of PRP to the site of CN-crush injury facilitates nerve regeneration and recovery of erectile function.Our research indicates that clinical application of PRP has potential repairing effect on CN and peripheral nerves.

Clinical Evaluation of Platelet Rich Growth Factors (PRGFS) in Treatment of Temporomandibular Joint Disc Displacement—Study Report

Objective: The aim of the study was to evaluate the effect of platelet rich growth factors (PRGFs) in treatment of temporomandibular joint disc displacement. Materials and Methods: The study subjects included 8 females having bilateral anterior disc displacement with reduction and 1 female having bilateral anterior disc displacement without reduction with the age range between 20 - 35 years. The process of obtaining PRGFs was carried out following the Anitua Technique. Results: Clinical parameters of Interincisal distance, Lateral excursion of mandible using digital caliper in millimeters and Visual Analogue Scale (VAS 0/10) for pain intensity score were used. All of these parameters were running through the intervals of two, four, and eight weeks till the end of the follow-up period at twenty-six weeks (six months). The participated patients showed the clinical improvement in the different clinical statuses such as interincisal distance;lateral excursion of mandible and Pain Score. Conclusion: the study reported early efficacy of PRGFs after the arthrocentesis of the joint in treatment of TMJ disc displacement, and according to our results, the injection of PRGFs could be a possible alternative treatment for patients who did not respond to standard treatment.

Experimental assessment of regenerative properties of platelet rich plasma on the human skin-a review

Several studies demonstrated the favorable effects of platelet rich plasma(PRP)on the skin and promoted its wide use in clinical practice.The growth factors stored in platelet alfa-granules allow for the tissue regeneration and the main fields of application of PRP in current clinical practice are the cartilage and musculoskeletal defects,osteoarthritis and other bone disorders,chronic and difficult to heal wounds,and aesthetic procedures.The relevant number of different PRP preparation protocols may explain the inconsistency of the different clinical outcomes reported in the literature.Despite the technological advances in PRP preparation,the objective assessment of the clinical efficacy of PRP from the literature reports still is difficult due to the low homogeneity of the samples in terms of both inclusion criteria and size.Therefore,it might be useful to establish standardized and reproducible experimental models to confirm and objectively measure the effectiveness of the available clinical results.Many experimental investigations have been carried out to objectively assess the effectiveness of PRP and platelet gel on several tissues.As far as the skin is concerned,the studies carried out to date are limited to fibroblasts in in-vitro culture models or to collagen,vascular supply,epithelium,and hair follicle in in-vivo models.The skin,however,is a very complex organ,where different cell lines coexist and feature complex mutual interaction.A model that combines the advantages of both in-vitro and in-vivo cultures is the ex-vivo model.The demonstration of the platelet derived growth factors effects through the ex-vivo human full-thickness skin culture model is a keystone to support the evidence of the PRP effectiveness,as it represents an objective,fast,reproducible,and ethical investigational method.

The inflammatory response of the pulp after direct capping with platelet-rich plasma and enamel matrix derivative:A controlled animal study

Aims: To evaluate the inflammatory response of the exposed pulp of incisor teeth in rats after direct pulp capping, using platelet rich plasma (PRP), enamel matrix derivate (EMD), mineral trioxide aggregate (MTA) and calcium hydroxide (Ca(OH)2). Methods: The study was conducted on 36 Wistar albino rats with a total of 144 incisor teeth. The pulps of 96 teeth of the rats were perforated and capped with different agents. Serving as the positive control group, the pulps of 24 teeth were only perforated and capped without capping agents, whereas the pulps of 24 teeth were used as the negative control group without being perforated (without any process). The research was ended with the extracting of the teeth on the 7th day-28th day. The teeth were taken to the routine and histological follows;cross sections were prepared and painted with hematoxylen & eosin. All of the sections were evaluated in terms of inflammatory reaction by histologic analysis taken by light microscope. Statistical analysis was used. The normal distribution of all data was tested with the Mann Whitney U and the differences between the groups were analyze dusing Kruskal Wallis test at 0.05 level. Results: There are no statistically significant differences in terms of inflammation type and necrosis among the treatment groups on 7 days’ post capping. However, improved inflammatory cell accumulation, hyperemia and lowest necrosis were observed from the samples treated with PRP (p < 0.05). Conversely, the EMD group indicated that the criteria of inflammation scores and hyper- emia were higher in the 28th day (p < 0.05). Conclusions: Most of cells accumulating in the PRP group and most necrosis were seen in the EMD group. These new PRP materials might serve as pulp capping biomaterials to induce initial healing response in the future.

Effectiveness of a Single High Dose of Platelet-Rich Plasma (PRP) Injection Over Corticosteroid and Hyaluronic Acid Injections on Osteoarthritis, Chronic Tendinitis and Tennis Elbow Treatment

Background: Corticosteroid, hyaluronic acid (HA) injections and Anti-inflammatory agents are considered as non-invasive treatments for knee osteoarthritis (OA), Chronic Tendinitis (CT) and Tennis elbow (TE) that are supposed to provide symptomatic relief and to help surgical delay intervention. Platelet rich plasma (PRP) is a biological component shown to be beneficial for different orthopedic dysfunctionalities treatment. The presence of GFs in PRPs such as transforming growth factor-β, insulin-like growth factor 1co-stimulate the mesenchymal stem cells and fibroblasts secretions and promotes the fibrin matrix formation which effectively drive the healing process, induces regenerative response and lead to the damage structure repair in orthopedics trauma. Methods: Three groups of a total of 30 patients presenting OA, CT and TE diagnosis, non-responding to corticosteroid, HA and non-steroid anti-inflammatory treatments were randomized to undergo one intra-articular injections of single high dose of PRP. The efficacy of Intra-articular PRP Injections was evaluated before the injection and one month after. The efficiency assessment score was based on [1] Knee injury and Osteoarthritis Outcome Score, [2] Physical Function Short Form (KOOS-PS) Arabic (KSA) version LK 1.0, [3] HOOS-Physical Function Short form (HOOS-PS), and [4] Macdermid patient-rated Tennis Elbow. Results: A significant reduction of pain and a marked improvement in movements was observed in the 3 patient’s groups, PRP-injected patients showed significantly higher values compared with baseline: (p < 0.005 vs baseline), improve functional status and reduce clearly the articular dysfunctions over the time. In our study, single High dose injection of PRP provided an overall superior clinical improvement compared with HA and corticosteroid treatments over the time and the different follow-up checkpoints of the study.

Platelet-rich plasma for regeneration of neural feedback pathways around dental implants: a concise review and outlook on future possibilities

Along with the development of new materials, advanced medical imaging and surgical techniques, osseointegrated dental implants are considered a successful and constantly evolving treatment modality for the replacement of missing teeth in patients with complete or partial edentulism. The importance of restoring the peripheral neural feedback pathway and thus repairing the lack of periodontal rnechanoreceptors after tooth extraction has been highlighted in the literature. Nevertheless, regenerating the nerve fibers and reconstructing the neural feedback pathways around osseointegrated implants remain a challenge. Recent studies have provided evidence that platelet-rich plasma （PRP） therapy is a promising treatment for musculoskeletal injuries. Because of its high biological safety, convenience and usability, PRP therapy has gradually gained popularity in the clinical field Although much remains to be learned, the growth factors from PRP might play key roles in peripheral nerve repair mechanisms. This review presents known growth factors contributing to the biological efficacy of PRP and illustrates basic and （pre-）clinical evidence regarding the use of PRP and its relevant products in peripheral nerve regeneration. In addition, the potential of local application of PRP for structural and functional recovery of iniured peripheral nerves around dental implants is discussed.

Platelet-rich plasma gel in combination with Schwann cells for repair of sciatic nerve injury

Bone marrow mesenchymal stem cells were isolated from New Zealand white rabbits, culture-expanded and differentiated into Schwann cell-like cells. Autologous platelet-dch plasma and Schwann cell-like cells were mixed in suspension at a density of 1 x 106 cells/mL, prior to introduction into a poly （lactic-co-glycolic acid） conduit. Fabricated tissue-engineered nerves were implanted into rabbits to bridge 10 mm sciatic nerve defects （platelet-rich plasma group）. Controls were established using fibrin as the seeding matrix for Schwann cell-like cells at identical density to construct tissue-engineered nerves （fibrin group）. Twelve weeks after implantation, toluidine blue staining and scanning electron microscopy were used to demonstrate an increase in the number of regenerating nerve fibers and thickness of the myelin sheath in the platelet-rich plasma group compared with the fibrin group. Fluoro-gold retrograde labeling revealed that the number of Fluoro-gold-positive neurons in the dorsal root ganglion and the spinal cord anterior horn was greater in the platelet-rich plasma group than in the fibrin group. Electrophysiological examination confirmed that compound muscle action potential and nerve conduction velocity were superior in the platelet-rich plasma group compared with the fibrin group. These results indicate that autologous platelet-rich plasma gel can effectively serve as a seeding matrix for Schwann cell-like cells to construct tissue-engineered nerves to promote perJpheral nerve regeneration.