Effect of platelet-rich plasma with self-assembled peptide on the rotator cuff tear model in rat

Skilled reaching test for shoulder function assessment in a rat model of rotator cuff tear: a pilot study

BACKGROUND

Functional assessments are crucial to evaluate treatment outcomes in clinical and animal studies on rotator cuff injuries. While gait analysis is commonly used to assess animal models of rotator cuff tears, it is less relevant for human patients as the human shoulder is typically assessed in a non-weight-bearing condition. The present study introduces the skilled reaching test as a shoulder functional assessment tool for rats, which allows for evaluation without weight bearing.

METHODS

In the control group, 8 male Sprague-Dawley rats received rotator cuff tear surgery without repair. In the rotator cuff repair group, 20 rats received rotator cuff repair at 4 weeks post rotator cuff tear. For the skilled reaching test, rats were trained to extend their forelimbs to fetch food pellets, and the number of trials, number of attempts and the success rate were recorded. The gait analysis and skilled reaching test were performed at baseline, 4 weeks post-tear, 1, 2, 4, and 8 weeks post-repair. The repeated measures analysis of variance was used to evaluate the effects of time on the shoulder function. The significance level was set at 0.05.

RESULTS

The skilled reaching test required 216 h to conduct, while the gait analysis took 44 h. In the rotator cuff repair group, gait performance significantly deteriorated at 1 week post-repair and restored to 4 weeks post-tear levels at 4 weeks post-repair. Regarding the skilled reaching test, the number of attempts, number of trials and the success rate decreased at 1 week post-repair. Subsequently, there was a brief rebound in performance observed at 2 weeks post-repair, followed by a continued decline in the number of attempts and trials. By 8 weeks post-repair, only the success rate had restored to levels similar to those observed at 4 weeks post-tear.

CONCLUSION

The skilled reaching test can detect functional deficiencies following rotator cuff tear and repair, while it requires high time and labour costs.

Hydrogel Development for Rotator Cuff Repair

Rotator cuff tears (RCTs) are common in shoulder disease and disability. Despite significant advances in surgical repair techniques, 20–70% of patients still have postoperative rotator cuff dysfunction. These functional defects may be related to retear or rotator cuff quality deterioration due to tendon retraction and scar tissue at the repair site. As an effective delivery system, hydrogel scaffolds may improve the healing of RCTs and be a useful treatment for irreparable rotator cuff injuries. Although many studies have tested this hypothesis, most are limited to laboratory animal experiments. This review summarizes differences in hydrogel scaffold construction, active ingredients, and application methods in recent research. Efforts to determine the indications of hydrogel scaffolds (with different constructions and cargos) for various types of RCTs, as well as the effectiveness and reliability of application methods and devices, are also discussed.

Application of suture anchors for a clinically relevant rat model of rotator cuff tear

Current rat model of rotator cuff (RC) tear could not mimic the suture anchor (SA) repair technique in the clinical practice. We designed a novel SA for RC repair of rats to establish a clinically relevant animal model. Small suture anchors that fit the rat shoulder were assembled. 60 rats were assigned to the transosseous (TO) repair group or SA repair group (n = 30/group). Micro‐computed tomography (Micro‐CT) scanning, biomechanical test and histological analysis were implemented at 2, 4, and 8‐week post‐repair. The failure load and stiffness in the SA group were significantly higher than those of TO group at 4‐week post‐repair. Micro‐computed tomography analysis showed the bone mineral density and trabecular thickness of the SA group were significantly lower than those of TO group. The SA group showed a better insertion continuity at 4‐week post‐repair compared to TO group. No significant difference in gait parameters was found between groups. Therefore, SA repair is applicable for the rat model of RC tears. The SA repair achieved superior RC tendon healing, but more extensive initial bone damage compared to TO repair, while the shoulder function was comparable. This model could replicate the current repair technique in the clinical situation and be considered for future preclinical studies on healing enhancement for RC tears. Statement of Clinical Significance: With high clinical relevance, this model may facilitate the translation from an animal study into clinical trials.

The effects of orthobiologics in the treatment of tendon pathologies: a systematic review of preclinical evidence

Purpose

The aim of this systematic review is to explore the current available knowledge about tendon disorders and orthobiologics derived by preclinical experiments to evaluate their role and efficacy in the different stages and conditions related to the tendon healing processes.

Methods

The systematic review was performed according to the PRISMA guidelines. Different electronic databases (MEDLINE, Web of Science, EMBASE) were searched for studies investigating orthobiologics (PRP and cell-based products from adipose tissue or bone marrow) in animal models or veterinary clinical trials for tendon pathologies (complete/partial tendon ruptures, rotator cuff tears, tendinopathy, enthesis-related injuries). Data regarding the specific product used, the treatment site/pathology, the host and the model were collected. The results were classified into the following categories: histological, biomechanical, molecular and imaging.

Results

A large pool of preclinical studies on tendon disorders have been found on platelet-rich plasma (PRP), while data about stromal vascular fraction (SVF) and bone marrow concentrate (BMAC) are still limited and frequently focused on expanded cells, rather than orthobiologics prepared at the point of care.

The effect of PRP is related to an acceleration of the healing process, without improvements in the final structure and properties of repaired tendon. Cell-based products have been reported to produce more durable results, but the level of evidence is currently insufficient to draw clear indications.

Conclusions

The preclinical results about orthobiologics applications to tendon pathologies would support the rationale of their clinical use and encourage the performance of clinical trials aimed to confirm these data in human subjects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-022-00468-w.

Evaluation of animal models and methods for assessing shoulder function after rotator cuff tear: A systematic review

BACKGROUND AND OBJECTIVE

Restoring the shoulder function is a crucial demand of patients with rotator cuff (RC) tears. Most preclinical studies only focused on biological and mechanical measurements. Functional assessment was less investigated in the preclinical studies. This study aims to review the literature of shoulder function in animal models for RC tears and evaluate the strengths and weaknesses of different shoulder functional assessments and animal models.

METHOD

A literature search for studies used RC tear animal models to evaluate changes in shoulder function was performed. We searched databases of PubMed, Embase, Web of Science, and Scopus from inception to September 2019. Animal species, functional parameters, injury and repair types, and study durations were summarised. Cluster analyses were then used to separate animal models with different levels of injury and timings of repair. The reliability and clinical relevance of the included assessments and animal models were then discussed.

RESULTS

Fourteen animal studies that related to shoulder function in animal models of RC tears were reviewed. Five methods (gait analysis, passive range of motion test, open field test, staircase test, and running endurance test) to assess shoulder function were identified. Single or massive RC tendon tears and immediate or delayed RC repair models were found. We reported and discussed factors to be considered when researchers would select assessments and animal models for different study purposes.

CONCLUSION

Based on current evidences, gait analysis is the most appropriate method to assess changes in shoulder function of animal models of RC tears. More studies are required to further elucidate the reliability of passive range of motion measurement, open field test, staircase test, and running endurance test. Models that use massive tears and delayed repair better represent the clinical condition found in humans.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

Using more clinically relevant animal models and assessments for shoulder function identified in this review may help to investigate the value of preclinical researches and promote translation of preclinical interventions into clinical practices.

Efficacy of platelet-rich plasma as an adjuvant to surgical carpal ligament release: a prospective, randomized controlled clinical trial

The purpose of this study is to evaluate the efficiency of local platelet-rich plasma (PRP) injection as an adjuvant treatment after carpal ligament release. We conducted a prospective randomized, triple-blinded, controlled trial. Fifty participants with mild to extreme carpal tunnel syndrome (CTS) were randomly assigned either to the PRP (n = 25) or the platelet-poor plasma (PPP, n = 25) group. After performing open surgical release of the carpal ligament, the inside of the carpal tunnel was irrigated with 3 mL of PRP or PPP according to each participant’s group allocation. The primary outcome was hand grip strength (HGS). Secondary outcomes were the time taken off work after surgery (in days) and scores on the Wong–Baker Faces Scale, Boston Carpal Tunnel Questionnaire, and Southampton Wound Assessment Scale. We evaluated patients before treatment and at 6-weeks. As expected, the pain levels, symptom severity, and functional status improved in all the patients after surgery. However, intragroup analysis revealed that only the participants in the PRP group had regained their pre-operative HGS levels at 6-weeks follow-up. These findings indicate that PRP is an effective adjuvant treatment in patients with mild to severe CTS who require surgery.

Nanofiber-based matrices for rotator cuff regenerative engineering

The rotator cuff consists of a cuff of soft tissue responsible for rotating the shoulder. Rotator cuff tendon tears are responsible for a significant source of disability and pain in the adult population. Most rotator cuff tendon tears occur at the bone-tendon interface. Tear size, patient age, fatty infiltration of muscle, have a major influence on the rate of retear after surgical repair. The high incidence of retears (up to 94% in some studies) after surgery makes rotator cuff injuries a critical musculoskeletal problem to address. The limitations of current treatments motivate regenerative engineering approaches for rotator cuff regeneration. Various fiber-based matrices are currently being investigated due to their structural similarity with native tendons and their ability to promote regeneration. This review will discuss the current approaches for rotator cuff regeneration, recent advances in fabrication and enhancement of nanofiber-based matrices and the development and use of complex nano/microstructures for rotator cuff regeneration. STATEMENT OF SIGNIFICANCE: Regeneration paradigms for musculoskeletal tissues involving the rotator cuff of the shoulder have received great interest. Novel technologies based on nanomaterials have emerged as possible robust solutions for rotator cuff injury and treatment due to structure/property relationships. The aim of the review submitted is to comprehensively describe and evaluate the development and use of nano-based material technologies for applications to rotator cuff tendon healing and regeneration.

Differing efficacies of autologous platelet-rich plasma treatment in reducing pain following rotator-cuff injury in a single patient

Rotator-cuff tears (RCTs) are typically associated with chronic pain. The most common treatment for reducing pain is the injection of cortisone into the injury site. An alternative and increasingly used technique is the injection of autologous platelet-rich plasma (PRP). A limitation of cortisone is its pain relief is short-lived, while PRP has the limitation of providing pain relief to only about 50% of patients, making its efficacy questioned, although when it is effective, its efficacy is longer than cortisone. Little is known about what accounts for these limitations. This paper presents results from a patient with RCTs causing excruciating pain who received an injection of PRP into that shoulder resulting in complete pain elimination that was ongoing at 2 years and 2 months. When 7-month severe posttrauma pain associated with the RCT developed in the contralateral shoulder, PRP prepared the same way and injected by the same person who performed the first injection provided no pain relief. However, a subsequent single cortisone injection resulted in complete pain elimination, which was ongoing at >15 months. These observations indicate that PRP can have inconsistent effects in reducing pain, not only between patients but also within the same patient. Further, although the pain relief induced by cortisone is normally not long-lasting, when given following a PRP injection, it can induce complete pain relief lasting >15 months. This paper discusses possible reasons for the variability in PRP efficacy on pain relief and addresses the possibility that when administered together, PRP and cortisone may act in a complementary manner, leading to significantly greater and longer-lasting pain relief.

Effects of intravesical therapy with platelet-rich plasma (PRP) and Bacillus Calmette-Guérin (BCG) in non-muscle invasive bladder cancer

This study describes the effects of a promising therapeutic alternative for non-muscle invasive bladder cancer (NMIBC) based on Bacillus Calmette-Guerin (BCG) intravesical immunotherapy combined with Platelet-rich plasma (PRP) in an animal model. Furthermore, this study describes the possible mechanisms of this therapeutic combination involving Toll-like Receptors (TLRs) 2 and 4 signaling pathways. NMIBC was induced by treating female Fischer 344 rats with N-methyl-N-nitrosourea (MNU). After treatment with MNU, the animals were distributed into four experimental groups: Control (without MNU) group, MNU (cancer) group, MNU + PRP group, MNU + BCG group and MNU + PRP + BCG group. Our results demonstrated that PRP treatment alone or associated with BCG triggered significant cytotoxicity in bladder carcinoma cells (HTB-9). Animals treated with PRP associated to BCG clearly showed better histopathological recovery from the cancer state and decrease of urothelial neoplastic lesions progression in 70% of animals when compared to groups that received the same therapies administered singly. In addition, this therapeutic association led to distinct activation of immune system TLRs 2 and 4-mediated, resulting in increased MyD88, TRIF, IRF3, IFN-γ immunoreactivities. Taken together, the data obtained suggest that interferon signaling pathway activation by PRP treatment in combination with BCG immunotherapy may provide novel therapeutic approaches for non-muscle invasive bladder cancer.

Will Platelet Rich Plasma Open New Era for Treatment of Rotator Cuff Tear?

No abstract available.

Apoptosis and rotator cuff tears: scientific evidence from basic science to clinical findings

INTRODUCTION

Excessive apoptosis has been hypothesized as possible cause of tendinopathy and tear in the tendons of the rotator cuff (RC). Different mechanisms and molecules play a key role in cell regulation. Biological interventions can affect the process of apoptosis to control the tendinopathy process, and may be useful to design new treatments.

SOURCE OF DATA

We identified basic science, in vitro and in vivo preclinical and clinical studies listed in the Pubmed Google Scholar, CINAHL, Cochrane Central and Embase Biomedical databases in English, Spanish, Italian and French concerning the effects of apoptosis on RC tendons.

AREAS OF AGREEMENT

The homeostasis between the apoptotic and inflammatory processes is dynamic and controlled by pro- and anti-apoptotic mechanisms and signals, with variable balance in different areas of the RC tendons in human specimens.

AREAS OF CONTROVERSY

Apoptosis can be identified along the whole tendon, not only in the area of the lesion. Therefore, it is not necessary to undertake wide debridement of the torn edges of the tendon when undertaking a repair.

GROWING POINTS

The identification of the various factors that control apoptosis and its mechanisms can help to design new treatments and exert positive effects in the recovery from tendon tears.

AREAS TIMELY FOR DEVELOPING RESEARCH

Further studies are needed to produce clear guidelines to determine how to balance the apoptosis process to reduce the failed healing response found in non-traumatic RC tears.

Effect of Bone Marrow Aspirate Concentrate-Platelet-Rich Plasma on Tendon-Derived Stem Cells and Rotator Cuff Tendon Tear

Bone marrow aspirate concentrates (BMACs) and platelet-rich plasma (PRP) are good sources to control the differentiation of tendon-derived stem cells (TDSCs), but there has been no study about the effect of the BMAC-PRP complex on TDSCs and tendinopathy. The aim of this study was to investigate the effect of BMAC-PRP on the TDSCs and to find the therapeutic effect of BMAC-PRP on the rotator cuff tendon tear. The chondrogenic and osteogenic potential of TDSCs decreased, but the adipogenic potential of TDSCs revealed no significant difference when they were cocultured with BMAC-PRP. Cell proliferation was significantly greater in TDSCs cocultured with BMAC-PRP than in TDSCs. The degree of wound closure (percentage) was different between TDSCs and TDSCs with BMAC-PRP. There was no significant difference in expression of collagen type I and type III in immunocytochemical staining in the presence of BMAC-PRP. Initial visual analog scale (VAS) score was 5.8 ± 1.9, which changed to 5.0 ± 2.3 at 3 weeks and 2.8 ± 2.3 at 3 months after the BMAC-PRP injection (p < 0.01). The American Shoulder Elbow Surgeon score changed from 39.4 ± 13.0 at baseline to 52.9 ± 22.9 at 3 weeks and 71.8 ± 19.7 at 3 months after the injection (p < 0.01). The initial torn area of the rotator cuff tendon was 30.2 ± 24.5 mm2, and this area was reduced to 22.5 ± 18.9 mm2 at 3 months, but the change was not significant (p > 0.05). The data indicate that BMAC-PRP enhances the proliferation and migration of TDSCs and prevents the aberrant chondrogenic and osteogenic differentiation of TDSCs, which might provide a mechanistic basis for the therapeutic benefits of BMAC-PRP for rotator cuff tendon tear.