Healing Effects of Platelet-Rich Plasma on Peripheral Nerve Injuries

Therapeutic modalities for iatrogenic late paresthesia in oral tissues innervated by mandibular branch of trigeminal nerve: a systematic review

BACKGROUND

The present systematic review intended to evaluate the current evidence on the modalities used for treating iatrogenic late paresthesia in the oral tissues innervated by the mandibular branch of the trigeminal nerve.

MAIN TEXT

As a common side effect of dental procedures, paresthesia can exert a profound adverse effect on patients' quality of life. The inferior alveolar nerve (IAN) and lingual nerve (LN) have the highest chance of injury during several dental procedures, including mandibular orthognathic surgeries, implant placement, extraction of the third molar, anesthetic injections, flap elevation, and endodontic treatments. Moreover, several methods have been proposed for treating iatrogenic late paresthesia, including photobiomodulation (PBM), microsurgery, medication, and close observation until achieving spontaneous recovery of sensation. However, no gold standard treatment for iatrogenic paresthesia has been agreed upon up to now. The present study included a comprehensive search of the databases of PubMed, Embase, Scopus, and Web of Science up to December 04, 2023, resulting in a total of 3122 related studies. Then, the titles, abstracts, and full texts of the studies were evaluated. Ultimately, seven controlled randomized trials (RCTs) were included in the final analysis. Also, the risk of bias was assessed using the Joanna Briggs Institute (JBI) critical appraisal checklist. Among all fields, randomization, allocation concealment, and data analysis were found to have the highest chance of bias in the included studies.

CONCLUSIONS

In conclusion, PBM, vitamin B12, and corticosteroids could accelerate the recovery of late paresthesia. However, considering the low sample size of the included studies and the high risk of methodological bias, it is recommended to perform further RCTs with robust study designs following Good Clinical Practice (GCP) guidelines to achieve more reliable results.

Efficacy of intra-ovarian injection of autologous platelet-rich plasma in women with poor responders: a systematic review and meta-analysis

CONTEXT

The effect of platelet-rich plasma (PRP) on ovarian reserve markers in poor ovarian response (POR) is challenging.

AIM

This systematic review and meta-analysis was, therefore, designed to evaluate the effectiveness of intra-ovarian injection of autologous PRP on improving ovarian reserve markers and assisted reproductive technology (ART) outcomes in infertile women with POR.

METHODS

A systematic search was conducted for the efficacy of intra-ovarian injection of autologous PRP on the improvement of ovarian reserve markers and ART outcomes in infertile women with POR. The methodological quality of the included studies was checked and eligible studies were included in the meta-analysis to find pooled results. Keywords were primary ovarian insufficiency, premature menopause, poor responder, poor ovarian response, diminished/decreased ovarian reserve, platelet-rich plasma, and intra-ovarian or a combination of them. The effect of PRP on fertility indices was evaluated using the standardized mean difference (SMD). The analysis was performed through STATA version 13.

KEY RESULTS

13 studies containing 1289 patients were included. Mean age, body mass index (BMI) and duration of infertility was 37.63 ± 2.66 years, 24 ± 1.23 kg/m2 and 4.79 ± 1.64 years, respectively. Most of the studies measured the outcomes 2-3/3 months after intra-ovarian injection of autologous PRP. The antral follicular count (AFC) after treatment by PRP is higher with an SMD of 0.95 compared to before treatment. The day 3 follicle-stimulating hormone (FSH) after treatment by PRP is lower with an SMD of - 0.25 compared to before treatment. The day 3 estradiol (E2) after treatment by PRP is higher with an SMD of 0.17 compared to before treatment. The anti-Mullerian hormone (AMH) after treatment by PRP is higher with an SMD of 0.44 compared to before treatment. The total oocytes number after treatment by PRP is higher with an SMD of 0.73 compared to before treatment. The number of MII oocytes after treatment by PRP is higher with an SMD of 0.63 compared to before treatment. The number of cleavage-stage embryos after treatment by PRP is higher with an SMD of 1.31 compared to before treatment. The number of day 5 embryo after treatment by PRP is higher with an SMD of 1.28 compared to before treatment. Pooled estimation of a meta-analysis of prevalence studies reported a prevalence of 22% for clinical pregnancy, 5% for spontaneous pregnancy and 21% for ongoing pregnancy following PRP therapy.

CONCLUSION

Intra-ovarian injection of PRP improved ovarian reserve markers with increasing AFC, serum level of AMH and day 3 E2 and decreasing serum level of day 3 FSH. In addition, this treatment improved ART outcomes through the increasing of number total oocytes, number of MII oocytes, number of cleavage-stage embryos and number of day 5 embryos in POR women.

IMPLICATIONS

Although treatment of POR women remains challenging, the use of intra-ovarian injection of autologous PRP in POR patients prior to IVF/ICSI cycles is a sign of new hope for increasing the success of IVF/ICSI. However, further well-organized, randomized controlled trials should be conducted to substantiate this result and recommend intra-ovarian injection of PRP as part of routine treatment in women with POR.

Recent Achievements in the Development of Biomaterials Improved with Platelet Concentrates for Soft and Hard Tissue Engineering Applications

Platelet concentrates such as platelet-rich plasma, platelet-rich fibrin or concentrated growth factors are cost-effective autologous preparations containing various growth factors, including platelet-derived growth factor, transforming growth factor β, insulin-like growth factor 1 and vascular endothelial growth factor. For this reason, they are often used in regenerative medicine to treat wounds, nerve damage as well as cartilage and bone defects. Unfortunately, after administration, these preparations release growth factors very quickly, which lose their activity rapidly. As a consequence, this results in the need to repeat the therapy, which is associated with additional pain and discomfort for the patient. Recent research shows that combining platelet concentrates with biomaterials overcomes this problem because growth factors are released in a more sustainable manner. Moreover, this concept fits into the latest trends in tissue engineering, which include biomaterials, bioactive factors and cells. Therefore, this review presents the latest literature reports on the properties of biomaterials enriched with platelet concentrates for applications in skin, nerve, cartilage and bone tissue engineering.

Ultrasound-Guided Interventions for Carpal Tunnel Syndrome: A Systematic Review and Meta-Analyses

Carpal tunnel syndrome (CTS) is the most common peripheral entrapment, and recently, ultrasound-guided perineural injection (UPIT) and percutaneous flexor retinaculum release (UPCTR) have been utilized to treat CTS. However, no systematic review or meta-analysis has included both intervention types of ultrasound-guided interventions for CTS. Therefore, we performed this review using four databases (i.e., PubMed, EMBASE, Scopus, and Cochrane) to evaluate the quality of evidence, effectiveness, and safety of the published studies on ultrasound-guided interventions in CTS. Among sixty studies selected for systemic review, 20 randomized treatment comparison or controlled studies were included in six meta-analyses. Steroid UPIT with ultrasound guidance outperformed that with landmark guidance. UPIT with higher-dose steroids outperformed that with lower-dose steroids. UPIT with 5% dextrose in water (D5W) outperformed control injection and hydrodissection with high-volume D5W was superior to that with low-volume D5W. UPIT with platelet-rich plasma outperformed various control treatments. UPCTR outperformed open surgery in terms of symptom improvement but not functional improvement. No serious adverse events were reported in the studies reviewed. The findings suggest that both UPIT and UPCTR may provide clinically important benefits and appear safe. Further treatment comparison studies are required to determine comparative therapeutic efficacy.

Platelet-Rich Plasma Gel-Loaded Collagen/Chitosan Composite Film Accelerated Rat Sciatic Nerve Injury Repair

Peripheral nerve injury (PNI) is a common clinical disease caused by severe limb trauma, congenital malformations, and tumor resection, which may lead to significant functional impairment and permanent disability. Nerve conduit as a method for treating peripheral nerve injury shows good application prospects. In this work, the COL/CS composite films with different mass ratios of 1:0, 1:1, and 1:3 were fabricated by combining physical doping. Physicochemical characterization results showed that the COL/CS composite films possessed good swelling properties, ideal mechanical properties, degradability and suitable hydrophilicity, which could meet the requirements of nerve tissue engineering. In vitro cell experiments showed that the loading of platelet-rich plasma (PRP) gel on the surface of COL/CS composite films could significantly improve the biocompatibility of films and promote the proliferation of Schwann cells. In addition, a rat model of sciatic nerve defect was constructed to evaluate the effect of COL/CS composite films on peripheral nerve repair and the results showed that COL/CS composite films loaded with PRP gel could promote nerve regeneration and functional recovery in rats with sciatic nerve injury, indicating that the combination of PRP gel with the COL/CS composite film would be a potential approach for the treatment of peripheral nerve injury.

Anatomical Comparative Study of the External Nasal Nerve in Caucasian and Asian: Application for Minimizing Nerve Damage in Rhinoplasty

Background

The numbness of the nasal tip is the main symptom of the external nasal nerve injury, especially after rhinoplasty. This postoperative syndrome can reduce the patient’s satisfaction with the operation. Having a better understanding of the anatomical structure and intraoperative protection can effectively avoid nerve injury. At present, the anatomical research on this nerve is all from Asia. This study aims to fill the gap in the anatomical study of this nerve in Caucasians and provides comparative results with Asians.

Material and Methods

A total of 20 Caucasian cadavers were embalmed using the Thiel method. On dissection, after complete exposure of the external nasal nerves, the distance between the exit point of the external nasal nerve and the nasal midline was measured, and the morphology of the nerves was compared with the Asian data. The nerves were classified into types based on their branching pattern.

Results

The nerve plane was the same as the Asian record. The distance ranged from 5.08 to 11.94 mm (mean, 8.31 ± 1.85 mm). This distance has statistical significant difference compared with the Asian population (P < 0.01). The average distance is larger, and the distribution range of the exit point is wider. On classification, 35 of 40 cases had the same type results as those previously reported, with the primary types I, II and III. Five new varieties were found which are classified as subtypes of the primary types and a new type IV. Furthermore, the bifurcation position in two-thirds of the type II cases and variations is proximal to that seen in the Asian population.

Conclusions

The anatomical structure of the external nasal nerve in Caucasians and Asians has obvious differences. This nerve in Caucasians is more likely to be damaged during rhinoplasty than Asians. Except the primary types, the classification of the external nasal nerve also includes subtypes and type IV.

Level of Evidence III

This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Treatment with platelet-rich plasma attenuates proprioceptor abnormalities in a rat model of postpartum stress urinary incontinence

INTRODUCTION AND HYPOTHESIS

Stress urinary incontinence (SUI) is the most prevalent form of urinary incontinence, and vaginal delivery is a major risk factor for developing SUI. We evaluated the hypothesis that applying the autologous platelet rich plasma (PRP) to the pelvic floor muscles via injection affects expression of proprioceptors and improves postpartum stress urinary incontinence (PSUI) in rats.

METHODS

Virgin female Sprague-Dawley rats were divided into control (n = 10) and experimental group(n = 20). Vaginal dilation was used to establish PSUI, and the rats in the experimental group were further divided into the PSUI group (n = 10) and PSUI+PRP group (n = 10). Pelvic floor muscles from rats in the PSUI+PRP group were positioned under ultrasound guidance for PRP injection. The morphology and number of pelvic floor muscle spindles were assessed using H&E staining, proprioceptors evaluated by gold chloride staining, and changes in the expression of neurotrophin-3 (NT-3) and skeletal myosin MY-32 determined by immunohistochemistry.

RESULTS

After 28 days,bladder leak point pressure (BLPP) and abdominal leaking-urine point pressure (ALPP) in rats with PSUI were significantly lower than in control animals (P<0.01). Both BLPP and ALPP increased significantly in the PSUI+PRP group (P<0.01). Compared with the control group, muscle spindle morphology and structure in the PSUI and PSUI+PRP groups had different pathological changes,with higher variations in the PSUI group. The positive signals for NT-3/MY-32 expression in control rats were higher than those from PSUI or PSUI+PRP groups, however, the expression for NT-3/MY-32 in PSUI+PRP animals was higher than that seen in the PSUI group (P < 0.01).

CONCLUSIONS

PSUI rats have an abnormal expression of pelvic proprioceptors, which affect proprioceptive function, and further the contractibility of pelvic floor muscles. A PRP injection may restore the sensory function of pelvic proprioceptors, thus improving urine leakage in PSUI rats.

Novel Motor-Sparing Ultrasound-Guided Neural Injection in Severe Carpal Tunnel Syndrome: A Comparison of Four Injectates

Nerve hydrodissection uses fluid injection under pressure to selectively separate nerves from areas of suspected entrapment; this procedure is increasingly viewed as potentially useful in treating carpal tunnel syndrome (CTS). The usage of normal saline (NS), 5% dextrose water (D5W), platelet-rich plasma (PRP), and hyaluronic acid (HA) as primary injectates for hydrodissection without an anesthetic can limit anesthetic-related toxicity and preserve the motor functions of the median nerve. Here, we describe a novel motor-sparing neural injection and compare the effect of these four injectates for severe CTS. We retrospectively reviewed the outcomes of 61 severe CTS cases after a single neural injection with NS, D5W, PRP, or HA. Outcomes were evaluated on the 1st and 6th months postinjection, including the Boston Carpal Tunnel Questionnaire (BCTQ) scores and the nerve cross-sectional area (CSA). The results revealed that PRP, D5W, and HA were more efficient than NS at all measured time points ( $p<0.05$ ), except for CSA at the 1st month between the NS and D5W groups. Single-injections of PRP and D5W seemed more effective than that of HA within 6 months postinjection for symptom and functional improvement (6th-month BCTQ-symptom, D5W vs. HA, $p=0.047$ ; 1st-month BCTQ-symptom, PRP vs. HA, $p=0.018$ ; 1st- and 6th-month BCTQ-function, D5W vs. HA, $p=0.002$ and 0.016, respectively; 1st-month BCTQ-function, PRP vs. HA, $p<0.001$ ). For reducing CSA, PRP and HA seemed more effective than D5W ( $\text{HA}>\text{PRP}>\text{D}5\text{W}$ on the 1st month and HA vs. D5W, $p=0.001$ ; $\text{PRP}>\text{HA}>\text{D}5\text{W}$ on the 6th month and PRP vs. D5W, $p=0.012$ ).

Stimulation of Neurite Outgrowth Using Autologous NGF Bound at the Surface of a Fibrous Substrate

Peripheral nerve injury still remains a major clinical challenge, since the available solutions lead to dysfunctional nerve regeneration. Even though autologous nerve grafts are the gold standard, tissue engineered nerve guidance grafts are valid alternatives. Nerve growth factor (NGF) is the most potent neurotrophic factor. The development of a nerve guidance graft able to locally potentiate the interaction between injured neurons and autologous NGF would be a safer and more effective alternative to grafts that just release NGF. Herein, a biofunctional electrospun fibrous mesh (eFM) was developed through the selective retrieval of NGF from rat blood plasma. The neurite outgrowth induced by the eFM-NGF systems was assessed by culturing rat pheochromocytoma (PC12) cells for 7 days, without medium supplementation. The biological results showed that this NGF delivery system stimulates neuronal differentiation, enhancing the neurite growth more than the control condition.

Effects of Platelet-Rich Fibrin/Collagen Membrane on Sciatic Nerve Regeneration

ABSTRACT

Alternative treatment approaches to improve the regeneration ability of damaged peripheral nerves are currently under investigation. The aim of the current study was to evaluate the effects of leucocyte/platelet-rich fibrin (L-PRF) with or without a collagen membrane as a supporter on crushed sciatic nerve healing in a rat model. Recovery of motor function and electrophysiologic measurements were evaluated at 4 weeks postoperatively. The whole number of myelinated axons, peripheral nerve axon density, average nerve fiber diameter (μm), and G-ratio were analyzed and compered among the groups. Functional, electrophysiological, and histological evaluations showed no significant difference among the groups with the exception of the L-PRF with collagen membrane groups that showed relatively positive effects on the functional and histological nerve recovery. In addition, the collagen membrane with L-PRF can be effect in nerve regeneration.

Fabrication and Characterization of Nanofibrous Poly (L-Lactic Acid)/Chitosan-Based Scaffold by Liquid-Liquid Phase Separation Technique for Nerve Tissue Engineering

Fabrication method is one of the essential factors which directly affect on the properties of scaffold. Several techniques have been well established to fabricate nanofibrous scaffolds such as electrospinning. However, preparing a three-dimensional (3-D) interconnected macro-pore scaffold essential for transporting the cell metabolites and nutrients is difficult using the electrospinning method. The main aim of this study was developing a highly porous scaffold by poly (L-lactic acid) (PLLA)/chitosan blend using liquid-liquid phase separation (LLPS) technique, a fast and cost-benefit method, in order to use in nerve tissue engineering. In addition, the effect of different polymeric concentrations on morphology, mechanical properties, hydrophilicity, in vitro degradation rate and pH alteration of the scaffolds were evaluated. Moreover, cell attachment, cell viability and cell proliferation of scaffolds as candidates for nerve tissue engineering was investigated. PLLA/chitosan blend not only had desirable structural properties, porosity, hydrophilicity, mechanical properties, degradation rate and pH alteration but also provided a favorable environment for attachment, viability, and proliferation of human neuroblastoma cells, exhibiting significant potential for nerve tissue engineering applications. However, the polymeric concentration in blend fabrication had influence on both characteristics and cell responses. It concluded that PLLA/chitosan nanofibrous 3-D scaffold fabricated by LLPS method as a suitable candidate for nerve tissue engineering.

Multi-walled carbon nanotube/hydroxyapatite nanocomposite with leukocyte- and platelet-rich fibrin for bone regeneration in sheep model

BACKGROUND

The aim of this study was to evaluate the effects of multi-walled carbon nanotubes/hydroxyapatite (MWCNT/HA) granules with or without leukocyte- and platelet-rich fibrin (L-PRF) on bone regeneration in cancellous bone of sheep model.

METHODS

Totally, 32 cylindrical holes were drilled in female sheep (n = 4) in the distal epiphysis and proximal metaphysis of right and left humerus and femur. The defects were randomly filled with (1) MWCNT/HA, (2) MWCNT/HA mixed with L-PRF, (3) L-PRF, and (4) left empty as control. After 8 weeks, defects were evaluated and compared radiographically using multi-slice computed tomographic (CT) scan and cone beam CT scans, histologically and histomorphometrically.

RESULTS

The results showed that there was no significant inflammation (> 10%) or foreign body reaction around the granules. The new lamellar bone was regenerated around the MWCNT/HA nanocomposite granules. Addition of L-PRF to MWCNT/HA demonstrated significantly improvement of new bone formation, about 27.40 ± 1.08%, in comparison with the L-PRF alone, about (12.16 ± 1.46%) (P < 0.01). Also, the rate of new bone formation was significantly greater with the use of MWCNT/HA granules (24.59 ± 1.54%) compared to the control (10.36 ± 1.17%) (P < 0.01).

CONCLUSION

Consequently, both biocompatibility and osteoconductivity of MWCNT/HA nanocomposite were demonstrated in the preclinical sheep model, and the use of L-PRF in combination with MWCNT/HA nanocomposite can improve bone regeneration.

Effects of titanium prepared platelet rich fibrin on facial nerve regeneration: an experimental study

INTRODUCTION

Facial nerve damage is a condition that causes functional, psychological, and cosmetic problems; and treatment methods need to be improved.

OBJECTIVE

We investigated the efficacy of titanium-prepared platelet-rich fibrin as a healing enhancer at the region of transection of the facial nerve.

METHODS

Twenty-seven New Zealand male rabbits were used in this study, divided into three experimental groups. Group 1, the sham group (n=7); Group 2, the suture group (n=10); and Group 3, the suture+T-PRF group (n=10). In Group 1, the facial nerve trunk was dissected, and no additional surgical intervention was performed. For Group 2, a transection was made to the facial nerve trunk and the nerve endings were sutured together. In Group 3, nerve endings were sutured after transection, and a titanium-prepared platelet-rich fibrin membrane was wrapped in a tube around the damaged area. All animals were followed up weekly for the presence of corneal reflex, whisker movement and low ears. Bilateral facial electromyography was performed both preoperatively and postoperatively at the 1st, 3rd, 5th, 7th, 10th weeks. Tissue samples obtained at the 10th week were histopathologically examined, and intra-group and inter-group comparisons were performed.

RESULTS

Subjects in Group showed improvement in whisker movement and ear drop one week earlier than Group 2. In Group 3, the nerve stimulation threshold required to trigger the compound muscle action potential had returned to values similar to the preoperative control values (11.31±2.16V) by 5 weeks postoperatively (12.51±3.97V), (p=0.249).

CONCLUSION

Titanium-prepared platelet-rich fibrin administration contributed to partial nerve healing both on a functional and an electrophysiological level.

Platelet-Rich Plasma Therapy in the Treatment of Diseases Associated with Orthopedic Injuries

Platelet-rich plasma (PRP) is an autologous platelet concentrate prepared from the whole blood that is activated to release growth factors (GFs) and cytokines and has been shown to have the potential capacity to reduce inflammation and improve tissue anabolism for regeneration. The use of PRP provides a potential for repair due to its abundant GFs and cytokines, which are key in initiating and modulating regenerative microenvironments for soft and hard tissues. Among outpatients, orthopedic injuries are common and include bone defects, ligament injury, enthesopathy, musculoskeletal injury, peripheral nerve injury, chronic nonhealing wounds, articular cartilage lesions, and osteoarthritis, which are caused by trauma, sport-related or other types of trauma, or tumor resection. Surgical intervention is often required to treat these injuries. However, for numerous reasons regarding limited regeneration capacity and insufficient blood supply of the defect region, these treatments commonly result in unsatisfactory outcomes, and follow-up treatment is challenging. The aim of the present review is to explore future research in the field of PRP therapy in the treatment of diseases associated with orthopedic injuries. Impact statement In recent years, platelet-rich plasma (PRP) has become widely used in the treatment of diseases associated with orthopedic injuries, and the results of numerous studies are encouraging. Due to diseases associated with orthopedic injuries being common in clinics, as a conservative treatment, more and more doctors and patients are more likely to accept PRP. Importantly, PRP is a biological product of autologous blood that is obtained by a centrifugation procedure to enrich platelets from whole blood, resulting in few complications, such as negligible immunogenicity from an autologous source, and it is also simple to produce through an efficient and cost-effective method in a sterile environment. However, the applicability, advantages, and disadvantages of PRP therapy have not yet been fully elucidated. The aim of the present review is to explore future research in the field of PRP therapy in the treatment of diseases associated with orthopedic injuries, as well as to provide references for clinics.

Strychnos nux-vomica L. seed preparation promotes functional recovery and attenuates oxidative stress in a mouse model of sciatic nerve crush injury

Background

Peripheral nerve injury is a debilitating condition that may lead to partial or complete motor, sensory and autonomic function loss and lacks effective therapy until date. Therefore, it is quite imperative to explore impending remedies for rapid and accurate functional retrieval following such conditions. Natural product-based intervention can prove effective to facilitate the process of functions regain.

Methods

Here, we investigated the effect of processed Strychnos nux-vomica seeds at a dose of 250 mg/kg body weight in a mouse model of induced Sciatic nerve lesion in promoting the recovery of the functions. A compression injury was induced in the Sciatic nerve of the right leg in the mice. Sensory function recovery was evaluated by hot-plate and formalin tests, whereas the motor function retrieval was assessed by measuring muscle grip strength, sciatic functional index, and muscle mass restoration. Oxidative stress and blood cell count were measured by biochemistry and haematological analyses.

Results

This study indicates that Strychnos nux-vomica seeds enhance the rate of recovery of both sensory and motor functions. It helps restore the muscle mass, attenuates total oxidant status and enhances the total anti-oxidant capacity of the biological system. Moreover, the treated animals manifested an enhanced glucose tolerance aptitude and augmented granulocyte and platelet counts. Improved oxidant control, enhanced glucose sensitivity and amended granulocyte and platelet counts are likely to contribute to the advantageous effects of Strychnos nux-vomica, and warrant further in-depth studies for deciphering possible mechanisms and identification of active constituent(s) responsible for these effects.

Conclusion

Strychnos nux-vomica seed offers functional recovery promoting effects following a mechanical injury to the Sciatic nerve and the possible reasons behind this effect can be reduced oxidative stress and improved glycaemic control. Further and detailed investigations can unravel this mystery.

Reactivating Ovarian Function through Autologous Platelet-Rich Plasma Intraovarian Infusion: Pilot Data on Premature Ovarian Insufficiency, Perimenopausal, Menopausal, and Poor Responder Women

Intraovarian platelet-rich plasma (PRP) infusion was recently introduced in the context of addressing ovarian insufficiency. Reporting on its effectiveness prior to adopting in clinical routine practice is imperative. This study aims to provide pilot data regarding PRP application for ovarian rejuvenation. Four pilot studies were conducted on poor ovarian response (POR), premature ovarian insufficiency (POI), perimenopause, and menopause, respectively. Each pilot study reports on thirty patients, 120 participants were recruited in total. All participants provided written informed consent prior to treatment. Primary outcome measures for the POR pilot study were levels of anti-müllerian hormone (AMH), antral follicle count (AFC) and oocyte yield. For the POI, perimenopausal and menopausal pilot studies primary outcome measures were restoration of menstrual cycle, and Follicle Stimulating Hormone (FSH) levels. A significant improvement on the hormonal profile and the ovarian reserve status was noted, along with improved intracytoplasmic sperm injection (ICSI) cycle performance concerning POR participants. Menstruation recovery was observed in 18 out of 30 POI patients, along with a statistically significant improvement on levels of AMH, FSH, and AFC. Similarly, 13 out of 30 menopausal women positively responded to PRP treatment. Finally, menstruation regularity, improved hormonal levels and AFC were reported for 24 out of 30 perimenopausal women. To conclude, PRP infusion appears to convey promising results in addressing ovarian insufficiency.

The use of autologous platelet-rich plasma (PRP) versus no intervention in women with low ovarian reserve undergoing fertility treatment: a non-randomized interventional study

PURPOSE

To investigate the impact of a 3-month course of intracortical injections of autologous platelet-rich plasma (PRP) upon ovarian reserve markers versus no intervention in women with low ovarian reserve prior to undergoing assisted reproductive technology (ART).

METHODS

Prospective controlled, non-randomized comparative study conducted in a private fertility clinic, in Venezuela. Women with abnormal ovarian reserve markers (FSH, AMH and AFC) who declined oocyte donation were allocated to one of the following groups according to patient choice: monthly intracortical ovarian PRP injections for three cycles, or no intervention. Primary outcomes were the change in FSH, AMH and AFC pre- and post-treatment. Secondary outcomes included the number of oocytes collected and fertilized, biochemical/clinical pregnancy rates and miscarriage and live birth rates.

RESULTS

Eighty-three women were included, of which 46 received PRP treatment and 37 underwent no intervention. Overall median age was 41 years (IQR 39-44). There were no demographic differences between the study groups. At the 3-month follow-up, women treated with PRP experienced a significant improvement in FSH, AMH and AFC, whereas there was no change in the control group. Furthermore, overall rates of biochemical (26.1% versus 5.4%, P = 0.02) and clinical pregnancy (23.9% versus 5.4%, P = 0.03) were higher in the PRP group, while there was no difference in the rates of first trimester miscarriage and live birth between groups.

CONCLUSION

PRP injections are effective and safe to improve markers of low ovarian reserve prior to ART, although further evidence is required to evaluate the impact of PRP on pregnancy outcomes.

Current Status of Therapeutic Approaches against Peripheral Nerve Injuries: A Detailed Story from Injury to Recovery

Peripheral nerve injury is a complex condition with a variety of signs and symptoms such as numbness, tingling, jabbing, throbbing, burning or sharp pain. Peripheral nerves are fragile in nature and can easily get damaged due to acute compression or trauma which may lead to the sensory and motor functions deficits and even lifelong disability. After lesion, the neuronal cell body becomes disconnected from the axon's distal portion to the injury site leading to the axonal degeneration and dismantlement of neuromuscular junctions of targeted muscles. In spite of extensive research on this aspect, complete functional recovery still remains a challenge to be resolved. This review highlights detailed pathophysiological events after an injury to a peripheral nerve and the associated factors that can either hinder or promote the regenerative machinery. In addition, it throws light on the available therapeutic strategies including supporting therapies, surgical and non-surgical interventions to ameliorate the axonal regeneration, neuronal survival, and reinnervation of peripheral targets. Despite the availability of various treatment options, we are still lacking the optimal treatments for a perfect and complete functional regain. The need for the present age is to discover or design such potent compounds that would be able to execute the complete functional retrieval. In this regard, plant-derived compounds are getting more attention and several recent reports validate their remedial effects. A plethora of plants and plant-derived phytochemicals have been suggested with curative effects against a number of diseases in general and neuronal injury in particular. They can be a ray of hope for the suffering individuals.

Effect of platelet-rich and platelet-poor plasma on peri-implant innervation in dog mandibles

Background

Autologous plasma fractions, such as platelet-rich plasma (PRP) and platelet-poor plasma (PPP), contain growth factors that can enhance neural cell survival and are therefore likely to have the ability to promote nerve regeneration. The present study compared the effect of PRP and PPP application on myelinated nerve density and diameter in the peri-implant bone region. In addition, the effect of healing time on nerve regeneration was assessed.

Materials and methods

Nine beagle dogs randomly received 54 dental implants in the bilateral mandible according to a split-mouth design. Each implant was randomly assigned to one of three implant protocols: delayed implant placement with delayed loading (DIP + DL) with local application of PRP, DIP + DL with local application of PPP and DIP + DL without any plasma additive. The animals were euthanized at 1, 3, and 6 months after loading (3 dogs per time point). Block biopsies were prepared for histomorphometry in the peri-implant bone within 500 μm around the implants.

Results

Myelinated nerve fibers were identified in the trabecular bone and in the osteons near the implants surface. The nerve fibers in the PRP group (median ± IQR; 2.88 ± 1.55 μm) had a significantly (p < 0.05) greater diameter compared to the PPP (2.40 ± 0.91 μm) and control (2.11 ± 1.16 μm) group. The nerve diameter after 6 months healing (3.18 ± 1.58 μm) was significantly (p < 0.05) greater compared to 1 (2.08 ± 0.89 μm) and 3 (2.49 ± 1.22 μm) months. No significant difference was found for myelinated nerve density between groups and healing time.

Conclusions

The present study showed that the healing time significantly influenced the diameter of the myelinated nerve fibers in peri-implant bone. PRP exerted a significant effect on the diameter of the myelinated nerve fibers as compared to PPP. Large-scale animal studies and longer follow-up periods are needed to confirm these findings and to verify whether platelet plasma can facilitate nerve regeneration process.

Involvement of PDGF-BB and IGF-1 in Activation of Human Schwann Cells by Platelet-Rich Plasma

BACKGROUND

Platelet-rich plasma contains high concentrations of growth factors that stimulate proliferation and migration of various cell types. Earlier experiments demonstrated that local platelet-rich plasma administration activates Schwann cells to improve axonal regeneration at a transected peripheral nerve lesion. However, the optimal concentration of human platelet-rich plasma for activation of human Schwann cells has not been determined, and mechanisms by which platelet-rich plasma activates Schwann cells remain to be clarified.

METHODS

Human Schwann cells were cultured with various concentrations of platelet-rich plasma in 5% fetal bovine serum/Dulbecco's Modified Eagle Medium. Cell viability, microchemotaxis, flow cytometry, and quantitative real-time polymerase chain reaction assays were performed to assess proliferation, migration, cell cycle, and neurotrophic factor expression of the human Schwann cells, respectively. Human Schwann cells were co-cultured with neuronal cells to assess their capacity to induce neurite extension. Neutralizing antibodies for platelet-derived growth factor-BB (PDGF-BB) and insulin-like growth factor-1 (IGF-1) were added to the culture to estimate contribution of these cytokines to human Schwann cell stimulation by platelet-rich plasma.

RESULTS

An addition of platelet-rich plasma at 5% strongly elevated proliferation, migration, and neurotrophic factor production of human Schwann cells. Both PDGF-BB and IGF-1 may be involved in mitogenic effect of platelet-rich plasma on human Schwann cells, and PDGF-BB may also play an important role in the migration-inducing effect of platelet-rich plasma. Neutralization of both PDGF-BB and IGF-1 cancelled the promoting effect of platelet-rich plasma on neurite-inducing activity of human Schwann cells.

CONCLUSION

This study may suggest the optimal concentration of platelet-rich plasma for human Schwann cell stimulation and potential mechanisms underlying the activation of human Schwann cells by platelet-rich plasma, which may be quite useful for platelet-rich plasma therapy for peripheral nerve regeneration.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

New bioresorbable wraps based on oxidized polyvinyl alcohol and leukocyte-fibrin-platelet membrane to support peripheral nerve neurorrhaphy: preclinical comparison versus NeuraWrap

Nerve wrapping improves neurorrhaphy outcomes in case of peripheral nerve injuries (PNIs). The aim of this preclinical study was to assess the efficacy of two novel biodegradable wraps made of a synthetic 1% oxidized polyvinyl alcohol (OxPVA) and a natural leukocyte-fibrin-platelet membrane (LFPm) versus the commercial product NeuraWrap. After rats sciatic nerve transection and neurorrhaphy, the wraps were implanted and compared for functional outcome, by sciatic function index assessment; structural characteristics, by histological/immunohistochemical analysis; ultrastructural features, by transmission electron microscopy. Moreover, a morphometric study was also performed and collagen distribution was observed by Second Harmonic Generation microscopy. After 12 weeks from implantation, all wraps assured nerve function recovery; no scar tissue/neuromas were visible at dissection. LFPm wraps were completely resorbed, while residues of OxPVA and NeuraWrap were observed. In all groups, biocompatibility was confirmed by the absence of significant inflammatory infiltrate. According to histological/immunohistochemical analysis and morphometric findings, OxPVA and LFPm wraps were both effective in preserving nerve integrity. These results assess that bioengineered OxPVA and LFPm wraps successfully guarantee favorable lesion recovery after PNI/neurorrhaphy and, in future, may be considered an interesting alternative to the commercial NeuraWrap.

Platelet-rich plasma improves the therapeutic efficacy of mesenchymal stem cells by enhancing their secretion of angiogenic factors in a combined radiation and wound injury model

Delayed wound healing after radiation exposure can cause serious cutaneous damage, and its treatment is a major clinical challenge. Although mesenchymal stem cells (MSCs) have emerged as a promising therapeutic agent in regenerative medicine, they alone do not produce satisfactory effects in a combined radiation and wound injury (CRWI) model. Here, we investigated the therapeutic effect of combined umbilical cord blood-derived (UCB)-MSCs and platelet-rich plasma (PRP) treatment on wound healing in a CRWI mouse model. First, we assessed the release of cytokines from UCB-MSCs cultured with PRP and observed changes in the expression of angiogenic factors. The angiogenic paracrine factors from UCB-MSCs cultured with PRP were assessed in human umbilical vein endothelial cells (HUVECs). To assess therapeutic efficacy, UCB-MSCs and PRP were topically implanted into a CRWT mouse model. Vascular endothelial growth factor (VEGF), a pro-angiogenic growth factor, urokinase-type plasminogen activator and contributor to VEGF-induced signalling were more highly expressed in conditioned media of UCB-MSCs cultured with PRP than in that of UCB-MSCs alone. Furthermore, conditioned media of UCB-MSCs cultured with PRP increased the formation of tube-like structures in HUVECs. Co-treatment of UCB-MSCs and PRP in a CRWI mouse model increased the wound closure rate and angiogenesis compared with an untreated irradiated group. Moreover, increased expression of VEGF and CD31 were observed in the wound tissue of co-treated mice compared with untreated irradiated mice. PRP stimulates the release of angiogenic factors from UCB-MSCs, and combined therapy of UCB-MSCs and PRP improves regeneration efficacy by enhancing angiogenesis in a CRWI model.

Fabrication of Poly(L-Lactic Acid)/Chitosan Scaffolds by Solid-Liquid Phase Separation Method for Nerve Tissue Engineering: An In Vitro Study on Human Neuroblasts

Polymeric scaffolds that support neural cell behaviors are attracting more attention. In the present study, solid-liquid phase separation technique is used to fabricate scaffolds made of poly(L-lactic acid) (PLLA) and chitosan (CS) blends to mimic both cellular microenvironment and anatomical structure of nerve tissue. The fabricated scaffolds favor characteristics of both natural and synthetic polymers. Different tests and assays including physical and mechanical ones (in vitro degradation rate, free radical release, hydrophilicity, and porosity measurements, microstructure observation, and mechanical tests) and cellular assays (cell attachment measurement and viability assessment) suggest that blend scaffolds prepared with this method support nerve cells for tissue engineering applications adequately and even better than scaffolds prepared with the same method but from pure PLLA or CS.

Comparison of the Regenerative Effects of Platelet-Rich Fibrin and Plasma Rich in Growth Factors on Injured Peripheral Nerve: An Experimental Study

PURPOSE

The aim of this study was to investigate the effects of platelet-rich fibrin (PRF) and plasma rich in growth factors (PRGF) on peripheral nerve injury in the early period of healing.

MATERIAL AND METHODS

Thirty Wistar albino rats were used in this study. Rats were divided into control (C), damaged (D), PRF, and PRGF groups. The left sciatic nerves of each group were identified as group C. Crush-type injury was performed on the right sciatic nerves of the D, PRF, and PRGF groups. In the PRF and PRGF groups, blood 2 mL was obtained to prepare the PRF and PRGF and the biomaterials were applied to the injured nerve area. After 8 weeks, functional, electrophysiologic, and stereological evaluations were performed.

RESULTS

For the electrophysiologic evaluation, the latency and amplitude values in the D, PRF, and PRGF groups were significantly lower than those in the C group (P > .05). According to the sciatic functional index result, there were significant differences between groups D and PRF and between groups D and PRGF (P = .000). For the stereological evaluations, although no significant difference was observed between the PRGF and C groups (P > .05), a significant difference was observed among the D, PRF, and PRGF groups for myelinated axon number. There were significant differences between groups D and PRF and between groups D and PRGF for axon area (P = .021 and .001, respectively). No significant difference was observed among the D, PRF, and PRGF groups for myelin sheath thickness and ratio of axon area to myelin sheath thickness (P > .05).

CONCLUSIONS

The results of this study suggest that PRGF increases nerve regeneration in the early period of healing and that the limited early action of PRF should be re-evaluated in the late period.

Is exclusion of leukocytes from platelet-rich plasma (PRP) a better choice for early intervertebral disc regeneration?

Background

Platelet-rich plasma (PRP) is becoming a promising strategy to treat early intervertebral disc degeneration (IDD) in clinics. Pure PRP without leukocytes (P-PRP) may decrease the catabolic and inflammatory changes in the early degenerated intervertebral discs. The aim of this study was to investigate the effects of P-PRP on nucleus pulposus-derived stem cells (NPSCs) isolated from early degenerated intervertebral discs in vitro.

Methods

NPSCs isolated from early degenerated discs of rabbits were treated with P-PRP or leukocyte-platelet-rich PRP (L-PRP) in vitro, followed by measuring cell proliferation, stem cell marker expression, inflammatory gene expression, and anabolic and catabolic protein expression by immunostaining, quantitative real-time polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assay.

Results

Cell proliferation was induced by P-PRP in a dose-dependent manner with maximum proliferation at 10% P-PRP dose. P-PRP induced differentiation of NPSCs into active nucleus pulposus cells. P-PRP mainly increased the expression of anabolic genes and relative proteins, aggrecan (AGC), collagen types II (Col II), while L-PRP predominantly increased the expression of catabolic and inflammatory genes, matrix metalloproteinase-1 (MMP-1), MMP-13, interleukin-1 beta (IL-1β), IL-6, tumor necrosis factor alpha (TNF-α), and protein production of IL-1β and TNF-α.

Conclusions

Leukocytes in PRP activate inflammatory and catabolic effects on NPSCs from early degenerated intervertebral discs. Hence, P-PRP may be a more suitable therapeutic strategy for early IDD.

Objective Assessment of Lingual Nerve Microsurgical Reconstruction

Lingual nerve (LN) injury is one of the most serious consequences of oral surgery. Prompt microsurgical reconstruction of the nerve can alleviate most of those symptoms leading to satisfactory functional recovery.Thirty-five patients with partial to complete LN injury underwent surgery in the period between January 2006 and May 2015. All patients underwent a preoperative clinical and neurological evaluation with the assessment of lingual tactile and pain sensory thresholds and masseteric inhibitory reflex.All patients underwent explorative surgery and direct microneurorrhaphy of distal and proximal stumps in case of complete lesion, while the removal of traumatic neuroma and the following microneurorrhaphy of distal and proximal stumps of the injured nerve was performed in case of incomplete lesion. Nerve grafting has always been avoided because of distal stump mobilization obtained by severing the submandibular branch of the LN.All patients but 1 exhibited good recovery of tongue sensation, never complete, both clinically and electrophysiologically: recovery of the excitability of masseteric inhibitory reflex suppression components SP1 and SP2 was observed, often with increased latencies but consistent with a functional recovery.All patients feeling pain preoperatively experienced complete relief of algic symptoms.The early microsurgical approach is the most suitable choice for the treatment of LN injuries.

3D printed TCP-based scaffold incorporating VEGF-loaded PLGA microspheres for craniofacial tissue engineering

OBJECTIVE

Vascularization is a critical process during bone regeneration/repair and the lack of tissue vascularization is recognized as a major challenge in applying bone tissue engineering methods for cranial and maxillofacial surgeries. The aim of our study is to fabricate a vascular endothelial growth factor (VEGF)-loaded gelatin/alginate/β-TCP composite scaffold by 3D printing method using a computer-assisted design (CAD) model.

METHODS

The paste, composed of (VEGF-loaded PLGA)-containing gelatin/alginate/β-TCP in water, was loaded into standard Nordson cartridges and promptly employed for printing the scaffolds. Rheological characterization of various gelatin/alginate/β-TCP formulations led to an optimized paste as a printable bioink at room temperature.

RESULTS

The in vitro release kinetics of the loaded VEGF revealed that the designed scaffolds fulfill the bioavailability of VEGF required for vascularization in the early stages of tissue regeneration. The results were confirmed by two times increment of proliferation of human umbilical vein endothelial cells (HUVECs) seeded on the scaffolds after 10 days. The compressive modulus of the scaffolds, 98±11MPa, was found to be in the range of cancellous bone suggesting their potential application for craniofacial tissue engineering. Osteoblast culture on the scaffolds showed that the construct supports cell viability, adhesion and proliferation. It was found that the ALP activity increased over 50% using VEGF-loaded scaffolds after 2 weeks of culture.

SIGNIFICANCE

The 3D printed gelatin/alginate/β-TCP scaffold with slow releasing of VEGF can be considered as a potential candidate for regeneration of craniofacial defects.

Autologous transplantation with fewer fibers repairs large peripheral nerve defects

Peripheral nerve injury is a serious disease and its repair is challenging. A cable-style autologous graft is the gold standard for repairing long peripheral nerve defects; however, ensuring that the minimum number of transplanted nerve attains maximum therapeutic effect remains poorly understood. In this study, a rat model of common peroneal nerve defect was established by resecting a 10-mm long right common peroneal nerve. Rats receiving transplantation of the common peroneal nerve in situ were designated as the in situ graft group. Ipsilateral sural nerves (10–30 mm long) were resected to establish the one sural nerve graft group, two sural nerves cable-style nerve graft group and three sural nerves cable-style nerve graft group. Each bundle of the peroneal nerve was 10 mm long. To reduce the barrier effect due to invasion by surrounding tissue and connective-tissue overgrowth between neural stumps, small gap sleeve suture was used in both proximal and distal terminals to allow repair of the injured common peroneal nerve. At three months postoperatively, recovery of nerve function and morphology was observed using osmium tetroxide staining and functional detection. The results showed that the number of regenerated nerve fibers, common peroneal nerve function index, motor nerve conduction velocity, recovery of myodynamia, and wet weight ratios of tibialis anterior muscle were not significantly different among the one sural nerve graft group, two sural nerves cable-style nerve graft group, and three sural nerves cable-style nerve graft group. These data suggest that the repair effect achieved using one sural nerve graft with a lower number of nerve fibers is the same as that achieved using the two sural nerves cable-style nerve graft and three sural nerves cable-style nerve graft. This indicates that according to the ‘multiple amplification’ phenomenon, one small nerve graft can provide a good therapeutic effect for a large peripheral nerve defect.