Stem cells and bFGF in tendon healing: Effects of lentiviral gene transfer and long-term follow-up in a rat Achilles tendon defect model

Growth factors in the treatment of Achilles tendon injury

Achilles tendon (AT) injury is one of the most common tendon injuries, especially in athletes, the elderly, and working-age people. In AT injury, the biomechanical properties of the tendon are severely affected, leading to abnormal function. In recent years, many efforts have been underway to develop effective treatments for AT injuries to enable patients to return to sports faster. For instance, several new techniques for tissue-engineered biological augmentation for tendon healing, growth factors (GFs), gene therapy, and mesenchymal stem cells were introduced. Increasing evidence has suggested that GFs can reduce inflammation, promote extracellular matrix production, and accelerate AT repair. In this review, we highlighted some recent investigations regarding the role of GFs, such as transforming GF-β(TGF-β), bone morphogenetic proteins (BMP), fibroblast GF (FGF), vascular endothelial GF (VEGF), platelet-derived GF (PDGF), and insulin-like GF (IGF), in tendon healing. In addition, we summarized the clinical trials and animal experiments on the efficacy of GFs in AT repair. We also highlighted the advantages and disadvantages of the different isoforms of TGF-β and BMPs, including GFs combined with stem cells, scaffolds, or other GFs. The strategies discussed in this review are currently in the early stages of development. It is noteworthy that although these emerging technologies may potentially develop into substantial clinical treatment options for AT injury, definitive conclusions on the use of these techniques for routine management of tendon ailments could not be drawn due to the lack of data.

Demographic trends of patients undergoing ophthalmic surgery in Ontario, Canada: a population-based study

OBJECTIVE

In this study, we investigated the demographic trends of patients undergoing ophthalmic surgeries based on geographic region, priority level, and sex.

METHODS AND ANALYSIS

This population-based retrospective cohort study used the Ontario Health Wait Times Information System (WTIS) database from 2010 to 2021. The WTIS contains non-emergent surgical case volume and wait time data for 14 different regions, three priority levels (high, medium and low) and six ophthalmic subspecialty procedures.

RESULTS

Over the study period, on average 83 783 women and 65 555 men underwent ophthalmic surgery annually in Ontario. Overall, women waited an aggregate mean of 4.9 days longer than men to undergo surgery, and this disparity persisted across all geographic and priority stratifications. The average age at the time of surgery has been increasing slowly at a rate of 0.02 years/year (95% CI 0.00 to 0.05), with women being 0.6 years older than men overall.

CONCLUSION

These findings indicate that women have consistently longer wait times than men. The results of this study may be a sign of systemic sex-based differences that could be affecting women who need to be further explored for health equity.

Tendon tissue engineering: An overview of biologics to promote tendon healing and repair

Tendons are dense connective tissues with a hierarchical polarized structure that respond to and adapt to the transmission of muscle contraction forces to the skeleton, enabling motion and maintaining posture. Tendon injuries, also known as tendinopathies, are becoming more common as populations age and participation in sports/leisure activities increases. The tendon has a poor ability to self-heal and regenerate given its intrinsic, constrained vascular supply and exposure to frequent, severe loading. There is a lack of understanding of the underlying pathophysiology, and it is not surprising that disorder-targeted medicines have only been partially effective at best. Recent tissue engineering approaches have emerged as a potential tool to drive tendon regeneration and healing. In this review, we investigated the physiochemical factors involved in tendon ontogeny and discussed their potential application in vitro to reproduce functional and self-renewing tendon tissue. We sought to understand whether stem cells are capable of forming tendons, how they can be directed towards the tenogenic lineage, and how their growth is regulated and monitored during the entire differentiation path. Finally, we showed recent developments in tendon tissue engineering, specifically the use of mesenchymal stem cells (MSCs), which can differentiate into tendon cells, as well as the potential role of extracellular vesicles (EVs) in tendon regeneration and their potential for use in accelerating the healing response after injury.

Effects of insoles adapted in flip-flop sandals for persistent heel pain: a protocol for a sham-controlled randomised trial

INTRODUCTION

Persistent heel pain is a prevalent complaint affecting up to 10% of the population. Insoles adapted in flip-flop sandals are an alternative treatment for pain and function of individuals with persistent heel pain, showing improvement within 12 weeks of treatment. Most studies considered foot posture and biomechanics to prescribe insoles for persistent heel pain, but few verified the effects of a 12-week treatment on pain catastrophising. This study will investigate the effects of insoles adapted in flip-flop sandals on pain intensity, function, functional walking capacity and pain catastrophising of individuals with persistent heel pain.

METHODS AND ANALYSIS

This is a protocol for a sham-controlled randomised trial. Eighty individuals with persistent heel pain will be assessed and randomised into two intervention groups: insoles adapted in flip-flop sandals and flip-flop sandals with sham (ie, flat) insoles. Assessments will be conducted at baseline (T0), after 6 weeks (T6), 12 weeks postintervention (T12) and after a 4-week follow-up (T16). The primary outcome will be the pain intensity, and secondary outcomes will be foot function, functional walking capacity and pain catastrophising. Analysis of variance with mixed design (if normal distribution) or Friedman's test (if not normal distribution) will verify intergroup and intragroup differences. Bonferroni post hoc tests will be performed in case of significant group or time interaction. Intent-to-treat analysis will be used, and a significance level of 5% and 95% CIs will be considered.

ETHICS AND DISSEMINATION

This study was approved by the research ethics committee of the Federal University of Rio Grande do Norte (registry no. 4,018,821). Results will be disseminated to individuals, submitted to a peer-reviewed journal and disclosed in scientific meetings.

TRIAL REGISTRATION NUMBER

NCT04784598.

New frontiers of tendon augmentation technology in tissue engineering and regenerative medicine: a concise literature review

Tissue banking programs fail to meet the demand for human organs and tissues for transplantation into patients with congenital defects, injuries, chronic diseases, and end-stage organ failure. Tendons and ligaments are among the most frequently ruptured and/or worn-out body tissues owing to their frequent use, especially in athletes and the elderly population. Surgical repair has remained the mainstay management approach, regardless of scarring and adhesion formation during healing, which then compromises the gliding motion of the joint and reduces the quality of life for patients. Tissue engineering and regenerative medicine approaches, such as tendon augmentation, are promising as they may provide superior outcomes by inducing host-tissue ingrowth and tendon regeneration during degradation, thereby decreasing failure rates and morbidity. However, to date, tendon tissue engineering and regeneration research has been limited and lacks the much-needed human clinical evidence to translate most laboratory augmentation approaches to therapeutics. This narrative review summarizes the current treatment options for various tendon pathologies, future of tendon augmentation, cell therapy, gene therapy, 3D/4D bioprinting, scaffolding, and cell signals.

Effects of prevention programmes on injury risk in military personnel: a systematic review with meta-analysis

INTRODUCTION

Exercise programmes have been used to prevent injuries in military personnel, as they can reduce modifiable risk factors for injuries. Our aim was to review the literature to evaluate the effects of different exercise protocols on the prevention of injuries in military personnel.

METHODS

A systematic literature review examined the effects of different exercise protocols on the prevention of musculoskeletal injuries in the military. Several databases were explored to find experimental studies that investigated the effects of prevention programmes on the risk of injury. We have extracted from the studies: profile of participants, sample size, study design and characteristics of the control group (CG), the type of intervention and the relative risk (RR) in the experimental group and CG, with their significance levels. For data analysis, we used the RevMan V.5.3 software. The measure of RR was investigated. The risk of publication bias was analysed with Begg's test.

RESULTS

A total of 13 694 titles and studies were recovered from the databases and by manual search. After the removal of duplicate titles and studies that did not meet the eligibility criteria, 17 studies were selected. The protocols were composed of neuromuscular training, stretching, agility training or combined exercises. The meta-analysis showed that injury prevention exercise programmes reduced the risk of musculoskeletal injuries in military personnel by 14% (RR=0.86; 95% CI=0.76 to 0.98).

CONCLUSION

Injury prevention exercise programmes promoted a slight reduction in the risk of musculoskeletal injuries in military personnel.

LEVEL OF EVIDENCE

Very low.

TRIAL REGISTRATION NUMBER

CRD 42017077946.

Acceptability of a task sharing and shifting model between family physicians and physiotherapists in French multidisciplinary primary healthcare centres: a cross-sectional survey

OBJECTIVES

The rising prevalence of musculoskeletal disorders increases pressure on primary care services. In France, patients with musculoskeletal disorders are referred to physiotherapist (PT) by family physician (FP). To improve access to musculoskeletal care, a new model of task sharing and shifting is implemented between FPs and PTs for patients with acute low back pain. This new model enables French PTs to expand their usual scope of practice by receiving patients as first-contact practitioner, diagnosing low back pain, prescribing sick leave and analgesic medication. The aim of this study is to investigate the acceptability of FPs and PTs regarding this new model.

DESIGN

A cross-sectional survey design was used. Acceptability was measured using a questionnaire on the perception of the model and the perception of PTs' skills to manage low back pain. Descriptive analyses were performed to compare results among participants.

SETTING

French FPs and PTs working in multidisciplinary primary healthcare centres were invited to complete an online survey.

PARTICIPANTS

A total of 174 respondents completed the survey (81 FPs and 85 PTs).

RESULTS

A majority of participants had a positive perception of the task sharing and shifting model. A majority of the participants were mostly or totally favourable towards the implementation of the model (FPs: n=46, 82% and PTs: n=40, 82%). The perceived level of competencies of PTs to manage acute low back pain was high. The confidence level of FPs was higher than that of PTs regarding PTs' ability to adequately diagnose low back pain, refer patient to physiotherapy and prescribe sick leave or analgesic medication.

CONCLUSION

Based on this limited sample of participants, there appears to be good acceptability of the task sharing and shifting model for acute low back pain. Additional studies are needed to better determine the factors affecting the acceptability of such a model.

The Functions and Mechanisms of Basic Fibroblast Growth Factor in Tendon Repair

Tendon injury is a disorder of the musculoskeletal system caused by overuse or trauma, which is characterized by pain and limitations in joint function. Since tendon healing is slowly and various treatments are generally ineffective, it remains a clinically challenging problem. Recent evidences suggest that basic fibroblast growth factor (bFGF) not only plays an important role in tendon healing, but also shows a positive effect in laboratory experimentations. The purpose of this review is to summarize the effects of bFGF in the tendon healing. Firstly, during the inflammatory phase, bFGF stimulates the proliferation and differentiation of vascular endothelial cells to foster neovascularization. Furthermore, bFGF enhances the production of pro-inflammatory factors during the early phase of tendon healing, thereby accelerating the inflammatory response. Secondly, the cell proliferation phase is accompanied by the synthesis of a large number of extracellular matrix components. bFGF speeds up tendon healing by stimulating fibroblasts to secrete type III collagen. Lastly, the remodeling phase is characterized by the transition from type III collagen to type I collagen, which can be promoted by bFGF. However, excessive injection of bFGF can cause tendon adhesions as well as scar tissue formation. In future studies, we need to explore further applications of bFGF in the tendon healing process.

What is the suitability of clinical vignettes in benchmarking the performance of online symptom checkers? An audit study

OBJECTIVE

Assess the suitability of clinical vignettes in benchmarking the performance of online symptom checkers (OSCs).

DESIGN

Observational study using a publicly available free OSC.

PARTICIPANTS

Healthily OSC, which provided consultations in English, was used to record consultation outcomes from two lay and four expert inputters using 139 standardised patient vignettes. Each vignette included three diagnostic solutions and a triage recommendation in one of three categories of triage urgency. A panel of three independent general practitioners interpreted the vignettes to arrive at an alternative set of diagnostic and triage solutions. Both sets of diagnostic and triage solutions were consolidated to arrive at a final consolidated version for benchmarking.

MAIN OUTCOME MEASURES

Six inputters simulated 834 standardised patient evaluations using Healthily OSC and recorded outputs (triage solution, signposting, and whether the correct diagnostic solution appeared first or within the first three differentials). We estimated Cohen's kappa to assess how interpretations by different inputters could lead to divergent OSC output even when using the same vignette or when compared with a separate panel of physicians.

RESULTS

There was moderate agreement on triage recommendation (kappa=0.48), and substantial agreement on consultation outcomes between all inputters (kappa=0.73). OSC performance improved significantly from baseline when compared against the final consolidated diagnostic and triage solution (p<0.001).

CONCLUSIONS

Clinical vignettes are inherently limited in their utility to benchmark the diagnostic accuracy or triage safety of OSC. Real-world evidence studies involving real patients are recommended to benchmark the performance of OSC against a panel of physicians.

What is the healthcare utilisation and out-of-pocket expenditure associated with osteoarthritis? A cross-sectional study

OBJECTIVE

To examine the use and out-of-pocket expenses resulting from consultations, products and practices across conventional, self-care, and complementary medicine (CM) treatments for osteoarthritis (OA) among Australian women.

DESIGN, SETTING AND PARTICIPANTS

A cross-sectional survey of 800 women from the 45 and Up Study who had reported a clinical diagnosis of OA.

OUTCOME MEASURES

Women's use of conventional, CM and self-prescribed treatments for OA and the associated out-of-pocket cost.

RESULTS

Completed questionnaires were returned by 403 women (50.4%). Their average time since the first diagnosis of OA was 15.4 years, and self-rated severity of OA was 5.1 (out of 10) over the past 12 months. During the previous year, 67.0% of the women consulted a doctor, 39.2% consulted an allied health practitioner and 34.7% consulted a CM practitioner for their OA. Some women (19%) consulted with practitioner(s) from all three practitioner groups, 27% consulted with practitioner(s) from two of the three practitioner groups, while 6% consulted with a CM practitioner only. Women with a greater time since diagnosis had more consultations, as did women who rated their OA as more severe. Women's average combined out-of-pocket expenditure for OA-related healthcare consultations, prescription medications, products, and practices was $673 per annum. Extrapolated to all Australian women with OA, aged 50 years and over, the total out-of-pocket expenditure for this condition is estimated to be $873 million per annum.

CONCLUSIONS

Australian women with OA use a range of conventional and CM consultations, self-care, products and practices to manage their condition, incurring significant out-of-pocket expenses. Given the high individual and societal burden of OA, there is a need for further research into the concurrent use of different healthcare resources with a view to providing safe, cost-effective management of OA across the healthcare system and the wider community.

Frailty in rheumatoidrmdopen-2021-002111 arthritis and its relationship with disease activity, hospitalisation and mortality: a longitudinal analysis of the Scottish Early Rheumatoid Arthritis cohort and UK Biobank

OBJECTIVE

To assess the prevalence of frailty in rheumatoid arthritis (RA) and its association with baseline and longitudinal disease activity, all-cause mortality and hospitalisation.

PARTICIPANTS

People with RA identified from the Scottish Early Rheumatoid Arthritis (SERA) inception cohort (newly diagnosed, mean age 58.2 years) and UK Biobank (established disease identified using diagnostic codes, mean age 59 years). Frailty was quantified using the frailty index (both datasets) and frailty phenotype (UK Biobank only). Disease activity was assessed using Disease Activity Score in 28 joints (DAS28) in SERA. Associations between baseline frailty and all-cause mortality and hospitalisation was estimated after adjusting for age, sex, socioeconomic status, smoking and alcohol, plus DAS28 in SERA.

RESULTS

Based on the frailty index, frailty was common in SERA (12% moderate, 0.2% severe) and UK Biobank (20% moderate, 3% severe). In UK Biobank, 23% were frail using frailty phenotype. Frailty index was associated with DAS28 in SERA, as well as age and female sex in both cohorts. In SERA, as DAS28 lessened over time with treatment, mean frailty index also decreased. The frailty index was associated with all-cause mortality (HR moderate/severe frailty vs robust 4.14 (95% CI 1.49 to 11.51) SERA, 1.68 (95% CI 1.26 to 2.13) UK Biobank) and unscheduled hospitalisation (incidence rate ratio 2.27 (95% CI 1.45 to 3.57) SERA 2.74 (95% CI 2.29 to 3.29) UK Biobank). In UK Biobank, frailty phenotype also associated with mortality and hospitalisation.

CONCLUSION

Frailty is common in early and established RA and associated with hospitalisation and mortality. Frailty in RA is dynamic and, for some, may be ameliorated through controlling disease activity in early disease.

Effectiveness of workplace exercise interventions in the treatment of musculoskeletal disorders in office workers: a systematic review

OBJECTIVE

To determine the effectiveness of workplace exercise interventions in the treatment of musculoskeletal disorders.

DESIGN

Systematic review of randomised controlled trials (RCTs).

DATA SOURCES

The bibliographical databases PubMed, CINAHL Plus, Cochrane, Scopus, ISI WoS and PeDRO were searched, with studies from 1 January 2010 to 31 December 2020 eligible for inclusion.

ELIGIBILITY CRITERIA

We included RCTs, reported in English or Spanish, with at least an intervention group performing workplace exercises among office workers with musculoskeletal disorders.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data and assessed the risk of bias. A narrative synthesis was carried out with a tabular method specifying the study characteristics following the SWiM (Synthesis Without Meta-Analysis) guideline for synthesis without meta-analysis. The revised Cochrane Risk of Bias (RoB-2) tool was used to analyse the risk of bias of the included studies.

RESULTS

Seven studies with a total of 967 participants met the inclusion criteria and were included in this review. Due to heterogeneity in different workplace exercise interventions, outcome measures and statistical analyses, it was not possible to conduct a meta-analysis and a narrative synthesis was performed. The interventions were classified into three categories: multiple body regions, neck and shoulder, and lower back. The seven studies concluded that workplace exercise interventions were effective in reducing musculoskeletal disorders and pain compared with other types of interventions or with control groups with no interventions. The RoB-2 tool found a high risk of bias in six of the seven studies.

CONCLUSIONS

The findings of the RCTs on workplace exercise interventions suggest that interventions were effective in treating musculoskeletal disorders among office workers. However, due to the high risk of bias of the included studies, no firm conclusions could be drawn and more high-quality studies are needed.

PROSPERO REGISTRATION NUMBER

CRD42020177462.

Known data on applied regenerative medicine in tendon healing

Tendons and ligaments are important structures in the musculoskeletal system. Ligaments connect various bones and provide stability in complex movements of joints in the knee. Tendon is made of dense connective tissue and transmits the force of contraction from muscle to bone. They are injured due to direct trauma in sports or roadside accidents. Tendon healing after repair is often poor due to the formation of fibro vascular scar tissues with low mechanical property. Regenerative techniques such as PRP (platelet-rich plasma), stem cells, scaffolds, gene therapy, cell sheets, and scaffolds help augment repair and regenerate tissue in this context. Therefore, it is of interest to document known data (repair process, tissue regeneration, mechanical strength, and clinical outcome) on applied regenerative medicine in tendon healing.

Characteristics of older adults with back pain associated with choice of first primary care provider: a cross-sectional analysis from the BACE-N cohort study

OBJECTIVES

To describe characteristics of older adults with back pain in primary care, and to assess associations between patient characteristics and type of first primary care provider (general practitioner (GP), physiotherapist (PT) or chiropractor).

DESIGN

Cross-sectional analysis from the Back Complaints in the Elders-Norway cohort study.

SETTING

Norwegian GP, PT and chiropractic primary care centres.

PARTICIPANTS

Patients aged ≥55 years seeking Norwegian primary care with a new episode of back pain were invited to participate. Between April 2015 and February 2020, we included 452 patients: 127 first visited a GP, 130 first visited a PT and 195 first visited a chiropractor.

PRIMARY AND SECONDARY OUTCOME MEASURES

For the first objective, the outcome measure was descriptive statistics of patient characteristics, covering the following domains: sociodemographic, general health, current and previous back pain, psychological and clinical factors. For the second objective, first primary care provider was the outcome measure. Associations between patient characteristics and visiting a GP or PT compared with a chiropractor were assessed with multiple multinomial regression analyses.

RESULTS

Median (IQR) age was 66 (59-72) years. Levels of back-related disability was moderate to severe, with a median (IQR) Roland-Morris Disability Questionnaire (range 0-24) score of 9 (5-13). Recurring episodes were common, 301 (67%) patients had monthly or yearly recurrences. Patients with worse back-related disability, longer duration of symptoms, lower expectations for full recovery and worse physical performance measured with the Back Performance Scale had higher odds of visiting a GP or PT compared with a chiropractor (p<0.05).

CONCLUSION

Older back pain patients in primary care had moderate to severe levels of back-related disability, and most had recurring episodes. Our results suggest that older adult's choice of first primary care provider was associated with important patient characteristics, which highlights the need for caution with generalisations of study results across primary care populations.

TRIAL REGISTRATION NUMBER

NCT04261309.

Perspectives and experiences of people who were randomly assigned to wait-and-see approach in a gluteal tendinopathy trial: a qualitative follow-up study

OBJECTIVE

To explore participants' perspectives on, and experiences of, being assigned to a wait-and-see arm of a gluteal tendinopathy trial.

DESIGN

Descriptive qualitative.

SETTING

General community in Brisbane and Melbourne, Australia.

PARTICIPANTS

Fifteen participants who had been randomly allocated to the wait-and-see group in a recent parallel group superiority clinical trial. That trial compared the wait-and-see approach to a physiotherapist-led education plus exercise approach, and an ultrasound-guided corticosteroid injection. The wait-and-see approach involved one physiotherapy session in which participants received reassurance, general advice and encouragement to stay active for the management of gluteal tendinopathy.

DATA COLLECTION AND ANALYSIS

Semistructured interviews were conducted by four interviewers in person or over the internet, audio recorded and transcribed verbatim. Transcripts were coded and data analysed using an inductive thematic approach.

RESULTS

Five themes were extracted from the interview transcripts: (1) Feeling disenfranchised by being assigned to a wait-and-see approach; (2) the importance of having a clinical and imaging diagnosis during screening for inclusion into the clinical trial; (3) feelings regarding the effectiveness of the approach; (4) the convenient and easy to follow nature of the wait-and-see approach and (5) the connotation of wait-and-see not always being perceived as an intervention.

CONCLUSIONS

Participants found the wait-and-see approach convenient and easy to follow, yet almost always felt disenfranchised that nothing was being done. Participants highlighted the importance of a definite clinical and imaging diagnosis.

TRIAL REGISTRATION NUMBER

ACTRN12612001126808; Post-results.

Double layer composite membrane for preventing tendon adhesion and promoting tendon healing

Electrospun membranes and hydrogels are widely used to prevent tendon adhesion. Hydrophobic anti-inflammatory drugs could be fully loaded on the electrospinning membrane through the electrospinning process, which can better prevent tendon adhesion. Basic fibroblast growth factor (bFGF) could promote tendon healing. However, the bioactivity of free bFGF is easily inactivated, therefore, a suitable carrier is needed. As a carrier, hydrogel has little effect on the bioactivity of the protein drugs. In this work, a poly(lactic-co-glycolic) acid (PLGA) electrospun membrane loaded with ibuprofen (IBU) was prepared and named EMI. Additionally, Methoxy poly(ethylene glycol)-block-poly(L-valine) (PEG-PLV) was synthesized. bFGF was added to the PEG-PLV solution, a hydrogel containing bFGF (PLVB) was obtained after gelling. PLVB was applied to the surface of EMI, a double-layer composite membrane named EMI-PLVB was obtained. This membrane was used to prevent Achilles tendon adhesion and promote healing. IBU and bFGF in EMI-PLVB were continuously released in vitro. The inflammatory factors at the tendon healing site were significantly reduced, and the production of type I collagen (Col- I) and type III Collagen (Col-III) at the tendon healing site was also increased in vivo. In conclusion, this double-layer composite membrane drug release system can effectively prevent tendon adhesion and promote tendon healing.

Transcriptome profiling of digital flexor tendons after injury in a chicken model

BACKGROUND

Modulation of tendon healing remains a challenge because of our limited understanding of the tendon repair process. Therefore, we performed the present study to provide a global perspective of the gene expression profiles of tendons after injury and identify the molecular signals driving the tendon repair process.

RESULTS

The gene expression profiles of flexor digitorum profundus tendons in a chicken model were assayed on day 3, weeks 1, 2, 4, and 6 after injury using the Affymetrix microarray system. Principal component analysis (PCA) and hierarchical cluster analysis of the differentially expressed genes showed three distinct clusters corresponding to different phases of the tendon healing period. Gene ontology (GO) analysis identified regulation of cell proliferation and cell adhesion as the most enriched biological processes. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis revealed that the cytokine-cytokine receptor interaction and extracellular matrix (ECM)-receptor interaction pathways were the most impacted. Weighted gene co-expression network analysis (WGCNA) demonstrated four distinct patterns of gene expressions during tendon healing. Cell adhesion and ECM activities were mainly associated with genes with drastic increase in expression 6 weeks after injury. The protein-protein interaction (PPI) networks were constructed to identify the key signaling pathways and hub genes involved.

CONCLUSIONS

The comprehensive analysis of the biological functions and interactions of the genes differentially expressed during tendon healing provides a valuable resource to understand the molecular mechanisms underlying tendon healing and to predict regulatory targets for the genetic engineering of tendon repair. Tendon healing, Adhesion, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Weighted Gene Co-expression Network Analysis, Protein-protein Interaction.

Biologic therapies for foot and ankle injuries

Introduction: The use of orthobiologics as supplemental treatment for foot and ankle pathologies have increased in the past decades. They have been used to improve the healing of bone and soft tissue injuries. There have been several studies that examined the use of biologics for knee and hip pathologies but the foot and ankle construct has unique features that must be considered.Areas covered: The biologics for foot and ankle injuries that are covered in this review are platelet-rich plasma (PRP), stem cells, growth factors, hyaluronic acid, bone grafts, bone substitutes, and scaffolds. These modalities are used in the treatment of pathologies related to tendon and soft tissue as well as cartilage.Expert opinion: The utilization of biological adjuncts for improved repair and regeneration of ankle injuries represents a promising future in our efforts to address difficult clinical problems. The application of concentrated bone marrow and PRP each represents the most widely studied and commonly used injection therapies with early clinical studies demonstrating promising results, research is also being done using other potential therapies such as stem cells and growth factors; further investigation and outcome data are still needed.

Regeneration of a full-thickness defect in rotator cuff tendon with umbilical cord-derived mesenchymal stem cells in a rat model

Although rotator cuff disease is a common cause of shoulder pain, there is still no treatment method that could halt or reveres its development and progression. The purpose of this study was to investigate the efficacy of umbilical cord-derived mesenchymal stem cells (UC MSCs) on the regeneration of a full-thickness rotator cuff defect (FTD) in a rat model. We injected either UC MSCs or saline to the FTD and investigated macroscopic, histological and biomechanical results and cell trafficking. Treatment with UC MSCs improved macroscopic appearance in terms of tendon thickness at two weeks, and inflammation, defect size, swelling/redness and connection surrounding tissue and slidability at four weeks compared to the saline group. Histologically, UC MSCs induced the tendon matrix formation recovering collagen organization, nuclear aspect ratio and orientation angle of fibroblast as well as suppressing cartilage-related glycosaminoglycan compared to saline group at four weeks. The UC MSCs group also improved ultimate failure load by 25.0% and 19.0% and ultimate stress by 27.3% and 26.8% at two and four weeks compared to saline group. UC MSCs labeled with PKH26 exhibited 5.3% survival at four weeks compared to three hours after injection. This study demonstrated that UC MSCs regenerated the FTD with tendon tissue similar properties to the normal tendon in terms of macroscopic, histological and biomechanical characteristics in a rat model.

In Vitro Innovation of Tendon Tissue Engineering Strategies

Tendinopathy is the term used to refer to tendon disorders. Spontaneous adult tendon healing results in scar tissue formation and fibrosis with suboptimal biomechanical properties, often resulting in poor and painful mobility. The biomechanical properties of the tissue are negatively affected. Adult tendons have a limited natural healing capacity, and often respond poorly to current treatments that frequently are focused on exercise, drug delivery, and surgical procedures. Therefore, it is of great importance to identify key molecular and cellular processes involved in the progression of tendinopathies to develop effective therapeutic strategies and drive the tissue toward regeneration. To treat tendon diseases and support tendon regeneration, cell-based therapy as well as tissue engineering approaches are considered options, though none can yet be considered conclusive in their reproduction of a safe and successful long-term solution for full microarchitecture and biomechanical tissue recovery. In vitro differentiation techniques are not yet fully validated. This review aims to compare different available tendon in vitro differentiation strategies to clarify the state of art regarding the differentiation process.

Tenogenic adipose-derived stem cell sheets with nanoyarn scaffolds for tendon regeneration

Tissue engineering, especially cell sheets-based engineering, offers a promising approach to tendon regeneration; however, obtaining a sufficient source of cells for tissue engineering applications is challenging. Adipose-derived stem cells (ASCs) are essential sources for tissue regeneration and have been shown to have the potential for tenogenic differentiation in vitro via induction by growth differentiation factor 5 (GDF-5). In this study, we explored the feasibility of ASCs cell sheets stimulated by GDF-5 for engineered tendon repair. As shown by quantitative polymerase chain reaction and western blotting, tenogenesis-related markers (Col I&III, TNMD, biglycan, and tenascin C) were significantly increased in GDF-5-induced ASCs cell sheets compared with the uninduced. Moreover, the levels of SMAD2/3 proteins and phospho-SMAD1/5/9 were significantly enhanced, demonstrating that GDF-5 may exert its functions through phosphorylation of SMAD1/5/9. Furthermore, the cell sheets were combined with P(LLA-CL)/Silk fibroin nanoyarn scaffolds to form constructs for tendon tissue engineering. Terminal deoxynucleotidyl transferase dUTP nick end labeling and immunofluorescence assays demonstrated favorable cell viability and tenogenesis-related marker expression in GDF-5-induced constructs. In addition, the constructs showed the potential for tendon repair in rabbit models, as demonstrated by histological, immunohistochemical, and biomechanical analyses. In our study, we successfully produced a new tissue-engineered tendon by the combination of GDF-5-induced ASCs cell sheets and nanoyarn scaffold which is valuable for tendon regeneration.

Regeneration of a full-thickness defect of rotator cuff tendon with freshly thawed umbilical cord-derived mesenchymal stem cells in a rat model

BACKGROUND

It is difficult to immediately use mesenchymal stem cells (MSCs) for the patient with rotator cuff disease because isolation and culture time are required. Thus, the MSCs would be prepared in advanced in cryopreserved condition for an "off-the-shelf" usage in clinic. This study investigated the efficacy of freshly thawed MSCs on the regeneration of a full-thickness tendon defect (FTD) of rotator cuff tendon in a rat model.

METHODS

We evaluated morphology, viability, and proliferation of cultured umbilical cord-derived MSCs (C-UC MSCs) and freshly thawed umbilical cord-derived MSCs (T-UC MSCs) at passage 10 in vitro. In animal experiments, we created a FTD in the supraspinatus of rats and injected the injured tendon with saline, cryopreserved agent (CPA; control), C-UC MSCs, and T-UC MSCs, respectively. Two and 4 weeks later, macroscopic, histological, biomechanical, and cell trafficking were evaluated. T test and ANOVA were used with SPSS. Differences with p < .05 were considered statistically significant.

RESULTS

T-UC MSCs had fibroblast-like morphology and showed greater than 97% viability and stable proliferation comparable to the C-UC MSCs at passage 10. In animal experiments, compared with the control group, the macroscopic appearance of the T-UC MSCs was more recovered at 2 and 4 weeks such as inflammation, defect size, neighboring tendon, swelling/redness, the connecting surrounding tissue and slidability. Histologically, the nuclear aspect ratio, orientation angle of fibroblasts, collagen organization, and fiber coherence were improved by 33.33%, 42.75%, 1.86-fold, and 1.99-fold at 4 weeks, and GAG-rich area decreased by 88.13% and 94.70% at 2 and 4 weeks respectively. Further, the T-UC MSCs showed enhanced ultimate failure load by 1.55- and 1.25-fold compared with the control group at both 2 and 4 weeks. All the improved values of T-UC MSCs were comparable to those of C-UC MSCs. Moreover, T-UC MSCs remained 8.77% at 4 weeks after injury, and there was no significant difference between C-UC MSCs and T-UC MSCs.

CONCLUSIONS

The morphology, viability, and proliferation of T-UC MSCs were comparable to those of C-UC MSCs. Treatment with T-UC MSCs could induce tendon regeneration of FTD at the macroscopic, histological, and biomechanical levels comparable to treatment with C-UC MSCs.

Multiple-dose tranexamic acid for perioperative blood loss in total knee arthroplasty in patients with rheumatoid arthritis：a single-blinded, randomised, parallel-controlled study protocol in China

INTRODUCTION

This clinical trial is designed to evaluate the effect of multiple-dose tranexamic acid (TXA) on perioperative blood loss in patients with rheumatoid arthritis (RA).

METHODS AND ANALYSIS

A randomised, single-blinded, parallel-controlled study will be designed. Patients with RA (age 50-75 years) undergoing unilateral primary end-stage total knee arthroplasty will be randomly divided into group A or group B. Group A will be treated with one dose of TXA (1 g; intravenous injection 3 hours postsurgery) and group B with three doses (1 g; intravenous injection at 3, 6 and 12 hours postsurgery) after surgery. The primary outcomes will be evaluated with blood loss, maximum haemoglobin drop and transfusion rate. The secondary outcomes will be evaluated with knee function and complications.

ETHICS AND DISSEMINATION

The Shanghai Guanghua Hospital of Integrated Traditional Chinese Medicine and Western Medicine Ethics Committee approved in this study in July 2019. Informed consent will be obtained from all participants. Results of the trial will be published in the Dryad and repository in a peer-reviewed journal. Additionally, deidentified data collected and analysed for this study will be available for review from the corresponding author on reasonable request.

TRIAL REGISTRATION NUMBER

ChiCTR1900025013.

Treatment of adhesions after Achilles tendon injury using focused ultrasound with targeted bFGF plasmid-loaded cationic microbubbles

Nonviral targeting technology has become promising as a form of gene therapy for diseases and injuries, such as Achilles tendon injuries. In this study, we used avidin–biotin bridge and positive–negative charge attractions to load the intercellular adhesion molecule-1 (ICAM-1) antibody and the basic fibroblast growth factor (bFGF) plasmid onto the surface of the microbubbles. The saturated loading capacity for 1.1 × 108 microbubble was 6.55 ± 0.53 µg. We established the ICAM-1 antigen microenvironment using tumor necrosis factor-alpha-stimulated human umbilical vein endothelial cells and found the targeting ability of the prepared microbubbles in vitro. In vivo, we also found that the injected targeted bFGF gene microbubbles expressed the bFGF gene better when compared with that of the control group. Furthermore, we evaluated adhesions after Achilles tendon injuries in rabbits using hematoxylin and eosin and immunohistochemical (IHC) staining methods. The collagen fibers were properly arranged in the tendon, and there was greater cellularity inside the tendon sheath and a clearer boundary between the internal and external tendon sheath than that of the control group. IHC staining showed greater ICAM-1 expression inside the tendon sheath when compared with outside the tendon sheath. In conclusion, targeted microbubbles can be a useful carrier of genes to provide gene therapy for the prevention of adhesions after tendon injury.

Pragmatic randomised controlled trial of very early etanercept and MTX versus MTX with delayed etanercept in RA: the VEDERA trial

Objectives

We sought to confirm in very early rheumatoid arthritis (ERA) a much greater superiority (30%) of first-line etanercept+methotrexate (ETN+MTX) over treat-to-target MTX (MTX-TT) than previously reported in ERA (14%); and explore whether ETN following initial MTX secures a comparable response to first-line ETN+MTX.

Methods

Pragmatic, open-label, randomised controlled trial of treatment-naïve ERA (≤12 months symptom), Disease Activity Score 28 joint (DAS28)-erythrocyte sedimentation rate (ESR) ≥3.2, rheumatoid factor (RF)+/−anticitrullinated peptide antibody (ACPA) positive or ultrasound power Doppler (PD) if RF and ACPA negative. Subjects were randomised 1:1 to ETN+MTX; or MTX-TT, escalated to ETN if week 24 DAS28-ESR ≥2.6 and intramuscular corticosteroid at protocolised time points. Primary endpoint of week 48 DAS28ESR remission with clinical and imaging secondary endpoints.

Results

We randomised 120 patients, 60 to each arm (71% female, 73% RF/84% ACPA positive, median (IQR) symptom duration 20.3 (13.1, 30.8) weeks; mean (SD) DAS28 5.1 (1.1)). Remission rates with ETN+MTX and MTX-TT, respectively, were 38% vs 33% at week 24; 52% vs 38% at week 48 (ORs 1.6, 95% CI 0.8 to 3.5, p=0.211). Greater, sustained DAS28-ESR remission observed with ETN+MTX versus MTX-TT (42% and 27%, respectively; p=0.035). PD was fully suppressed by week 48 in over 90% in each arm. Planned exploratory analysis revealed OR 2.84, 95% CI 0.8 to 9.6) of achieving remission after 24 weeks of ETN administered first line compared with administered post-MTX.

Conclusions

Compared with remission rates typically reported with first-line tumour necrosis factor inhabitor+MTX versus MTX-TT, we did not demonstrate a larger effect in very ERA. Neither strategy conferred remission in the majority of patients although ultrasound confirmed local inflammation suppression. Poorer ETN response following failure of MTX-TT is also suggested.

Trial registration number

NCT02433184

Tendon and Ligament Healing and Current Approaches to Tendon and Ligament Regeneration

Ligament and tendon injuries are common problems in orthopedics. There is a need for treatments that can expedite nonoperative healing or improve the efficacy of surgical repair or reconstruction of ligaments and tendons. Successful biologically-based attempts at repair and reconstruction would require a thorough understanding of normal tendon and ligament healing. The inflammatory, proliferative, and remodeling phases, and the cells involved in tendon and ligament healing will be reviewed. Then, current research efforts focusing on biologically-based treatments of ligament and tendon injuries will be summarized, with a focus on stem cells endogenous to tendons and ligaments. Statement of clinical significance: This paper details mechanisms of ligament and tendon healing, as well as attempts to apply stem cells to ligament and tendon healing. Understanding of these topics could lead to more efficacious therapies to treat ligament and tendon injuries. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:7-12, 2020.

Relaxin inhibits patellar tendon healing in rats: a histological and biochemical evaluation

BACKGROUND

Female patients are more likely to have tendon injuries than males, especially those who has a higher concentration of relaxin. Previous studies have demonstrated that relaxin attenuates extracellular matrix (ECM) formation. However, the mechanism of relaxin on tendon repair remains unclear. We hypothesize that relaxin inhibits tendon healing by disrupting collagen synthesis.

METHODS

A patellar tendon window defect model was established using Sprague-Dawley rats. The center of the patellar tendon was removed from the patella distal apex and inserted to the tibia tuberosity in width of 1 mm. Then, the rats were injected with saline (0.2 μg/kg/day) or relaxin (0.2 μg/kg/day) for two and four weeks, which was followed by biomechanical analysis and histological and histochemical examination.

RESULTS

Mechanical results indicated that relaxin induces a significant decrease in tear resistance, stiffness, and Young's modulus compared to those rats without relaxin treatment. In addition, it was shown that relaxin activates relaxin family peptide receptor 1(RXFP1), disturbs the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteases (TIMPs), and reduces the deposition of collagen in injury areas.

CONCLUSIONS

Relaxin impairs tendon healing in rats. Also, relaxin might lead to tendon injury more commonly for females than males.

Use of Human Placenta-Derived Cells in a Preclinical Model of Tendon Injury

BACKGROUND

Emerging data suggest that human cells derived from extraembryonic tissues may have favorable musculoskeletal repair properties. The purpose of this study was to determine whether the injection of human placenta-derived mesenchymal-like stromal cells, termed placental expanded cells (PLX-PAD), would improve tendon healing in a preclinical model of tendinopathy.

METHODS

Sixty male Sprague-Dawley rats underwent bilateral patellar tendon injection with either saline solution (control) or PLX-PAD cells (2 × 10 cells/100 µL) 6 days after collagenase injection to induce tendon degeneration. Animals were killed at specific time points for biomechanical, histological, and gene expression analyses of the healing patellar tendons.

RESULTS

Biomechanical testing 2 weeks after the collagenase injury demonstrated better biomechanical properties in the tendons treated with PLX-PAD cells. The load to failure of the PLX-PAD-treated tendons was higher than that of the saline-solution-treated controls at 2 weeks (77.01 ± 10.51 versus 58.87 ± 11.97 N, p = 0.01). There was no significant difference between the 2 groups at 4 weeks. There were no differences in stiffness at either time point. Semiquantitative histological analysis demonstrated no significant differences in collagen organization or cellularity between the PLX-PAD and saline-solution-treated tendons. Gene expression analysis demonstrated higher levels of interleukin-1β (IL-1β) and IL-6 early in the healing process in the PLX-PAD-treated tendons.

CONCLUSIONS

Human placenta-derived cell therapy induced an early inflammatory response and a transient beneficial effect on tendon failure load in a model of collagenase-induced tendon degeneration.

CLINICAL RELEVANCE

Human extraembryonic tissues, such as the placenta, are an emerging source of cells for musculoskeletal repair and may hold promise as a point-of-care cell therapy for tendon injuries.

Effects of transplantation of FGF-2-transfected MSCs and XACB on TNF-α expression with avascular necrosis of the femoral head in rabbits

Objective: The present study aimed to investigate the effect of the transplantation of basic fibroblast growth factor (FGF-2) gene-transfected mesenchymal stem cells (MSCs) and xenogeneic antigen-cancellous bone (XACB) on tumor necrosis factor-α (TNF-α) expression with avascular necrosis of the femoral head (ANFH) in rabbits. Methods: The models of steroid-induced osteonecrosis in rabbits were randomly divided into five groups: A (model), B (XACB), C (XACB + MSCs), D (XACB + MSCs + LV), and E (XACB + MSCs + LV-FGF-2) groups. The therapeutic effect was evaluated by Hematoxylin and Eosin (H&E) staining. Immunohistochemical and RT-PCR assays were used to detect the protein and mRNA expression of TNF-α in the femoral head, respectively. Results: At 12 weeks after the operation, the defect in rabbits in group E was completely repaired, while defects in rabbits in the other groups were not completely repaired, and the area of new bone formation was higher, when compared with the other groups (P<0.05). Furthermore, the protein and mRNA expression TNF-α was lower at 3, 6, and 12 weeks after surgery, when compared with the other groups, and the difference was statistically significant (P<0.05). Conclusion: FGF-2/MSCs/XACB could promote the repair of ANFH, and may be correlated to the inhibition of TNF-α expression.

Pulsed Electromagnetic Fields Improve Tenogenic Commitment of Umbilical Cord-Derived Mesenchymal Stem Cells: A Potential Strategy for Tendon Repair-An In Vitro Study

Tendon repair is a challenging procedure in orthopaedics. The use of mesenchymal stem cells (MSCs) and pulsed electromagnetic fields (PEMF) in tendon regeneration is still investigational. In this perspective, MSCs isolated from the human umbilical cord (UC) may represent a possible candidate for tendon tissue engineering. The aim of the study is to evaluate the effect of low-frequency PEMF on tenogenic differentiation of MSCs isolated from the human umbilical cord (UC-MSCs) in vitro. 15 fresh UC samples from women with healthy pregnancies were retrieved at the end of caesarean deliveries. UC samples were manually minced into small fragments (less than 4 mm length) and cultured in MSC expansion medium. Part of the UC-MSCs was subsequently cultured with PEMF and tenogenic growth factors. UC-MSCs were subjected to pulsed electromagnetic fields for 2 h/day, 4 h/day, or 8 h/day. UC-MSCs cultured with FGF-2 and stimulated with PEMF showed a greater production of collagen type I and scleraxis. The prolonged exposure to PEMF was also related to the greatest expression of tenogenic markers. Thus, the exposure to PEMF provides a positive preconditioning biophysical stimulus, which may enhance UC-MSC tenogenic potential.

Stem cells as delivery vehicles for regenerative medicine-challenges and perspectives

The use of stem cells as carriers for therapeutic agents is an appealing modality for targeting tissues or organs of interest. Combined delivery of cells together with various information molecules as therapeutic agents has the potential to enhance, modulate or even initiate local or systemic repair processes, increasing stem cell efficiency for regenerative medicine applications. Stem-cell-mediated delivery of genes, proteins or small molecules takes advantage of the innate capability of stem cells to migrate and home to injury sites. As the native migratory properties are affected by in vitro expansion, the existent methods for enhancing stem cell targeting capabilities (modified culture methods, genetic modification, cell surface engineering) are described. The role of various nanoparticles in equipping stem cells with therapeutic small molecules is revised together with their class-specific advantages and shortcomings. Modalities to circumvent common challenges when designing a stem-cell-mediated targeted delivery system are described as well as future prospects in using this approach for regenerative medicine applications.

Stem cells as delivery vehicles for regenerative medicine-challenges and perspectives

The use of stem cells as carriers for therapeutic agents is an appealing modality for targeting tissues or organs of interest. Combined delivery of cells together with various information molecules as therapeutic agents has the potential to enhance, modulate or even initiate local or systemic repair processes, increasing stem cell efficiency for regenerative medicine applications. Stem-cell-mediated delivery of genes, proteins or small molecules takes advantage of the innate capability of stem cells to migrate and home to injury sites. As the native migratory properties are affected by in vitro expansion, the existent methods for enhancing stem cell targeting capabilities (modified culture methods, genetic modification, cell surface engineering) are described. The role of various nanoparticles in equipping stem cells with therapeutic small molecules is revised together with their class-specific advantages and shortcomings. Modalities to circumvent common challenges when designing a stem-cell-mediated targeted delivery system are described as well as future prospects in using this approach for regenerative medicine applications.

Rescue plan for Achilles: Therapeutics steering the fate and functions of stem cells in tendon wound healing

Due to the increasing age of our society and a rise in engagement of young people in extreme and/or competitive sports, both tendinopathies and tendon ruptures present a clinical and financial challenge. Tendon has limited natural healing capacity and often responds poorly to treatments, hence it requires prolonged rehabilitation in most cases. Till today, none of the therapeutic options has provided successful long-term solutions, meaning that repaired tendons do not recover their complete strength and functionality. Our understanding of tendon biology and healing increases only slowly and the development of new treatment options is insufficient. In this review, following discussion on tendon structure, healing and the clinical relevance of tendon injury, we aim to elucidate the role of stem cells in tendon healing and discuss new possibilities to enhance stem cell treatment of injured tendon. To date, studies mainly apply stem cells, often in combination with scaffolds or growth factors, to surgically created tendon defects. Deeper understanding of how stem cells and vasculature in the healing tendon react to growth factors, common drugs used to treat injured tendons and promising cellular boosters could help to develop new and more efficient ways to manage tendon injuries.

Evaluation of injectable anaesthesia with five medetomidine-midazolam based combinations in Egyptian fruit bats (Rousettus aegyptiacus)

Egyptian fruit bats are increasingly used as model animals in neuroscience research. Our aim was to characterize suitable injectable anaesthesia for this species, possibly replacing inhalant anaesthesia, thus minimizing occupational health hazards. Eight bats were randomly assigned by a crossover design for subcutaneously administered combinations of medetomidine-midazolam with: saline (MM-Sal), ketamine (MM-Ket), fentanyl (MM-Fen), morphine (MM-Mor), or butorphanol (MM-But). The anaesthetic depth and vital signs were monitored at baseline and every 10 min until bats recovered. If after 180 min the bats did not recover, atipamezole was administered. Mean induction times were 7–11.5 min with all combinations. Twitching during induction was common. All combinations produced anaesthesia, with significantly decreased heart rate (from 400 to 200 bpm) and respiratory rate (from 120–140 to 36–65 rpm). Arrhythmia and irregular breathing patterns occurred. MM-Fen, MM-Mor, and MM-But depressed respiration significantly more than MM-Sal. Time to first movement with MM-Ket and MM-But lasted significantly longer than with MM-Sal. Recovery time was significantly shorter in the MM-Sal (88 min) in comparison to all other treatments, and it was significantly longer in the MM-But (159 min), with atipamezole administered to four of the eight bats. In conclusion, all five anaesthetic protocols are suitable for Egyptian fruit bats; MM-Ket produces long anaesthesia and minimal respiratory depression, but cannot be antagonized completely. MM-Fen, MM-Mor, and MM-But depress respiration, but are known to produce good analgesia, and can be fully antagonized. Administration of atipamezole following the use of MM-But in Egyptian fruit bats is recommended.

Extracellular matrix protein production in human adipose-derived mesenchymal stem cells on three-dimensional polycaprolactone (PCL) scaffolds responds to GDF5 or FGF2

Purpose

The poor healing potential of intra-articular ligament injuries drives a need for the development of novel, viable 'neo-ligament' alternatives. Ex vivo approaches combining stem cell engineering, 3-dimensional biocompatible scaffold design and enhancement of biological and biomechanical functionality via the introduction of key growth factors and morphogens, represent a promising solution to ligament regeneration.

Methods

We investigated growth, differentiation and extracellular matrix (ECM) protein production of human adipose-derived mesenchymal stem/stromal cells (MSCs), cultured in 5% human platelet lysate (PL) and seeded on three-dimensional polycaprolactone (PCL) scaffolds, in response to the connective-tissue related ligands fibroblast growth factor 2 (basic) (FGF2) and growth and differentiation factor-5 (GDF5). Phenotypic alterations of MSCs under different biological conditions were examined using cell viability assays, real time qPCR analysis of total RNA, as well as immunofluorescence microscopy.

Results

Phenotypic conversion of MSCs into ECM producing fibroblastic cells proceeds spontaneously in the presence of human platelet lysate. Administration of FGF2 and/or GDF5 enhances production of mRNAs for several ECM proteins including Collagen types I and III, as well as Tenomodulin (e.g., COL1A1, TNMD), but not Tenascin-C (TNC). Differences in the in situ deposition of ECM proteins Collagen type III and Tenascin-C were validated by immunofluorescence microscopy.

Summary

Treatment of MSCs with FGF2 and GDF5 was not synergistic and occasionally antagonistic for ECM production. Our results suggest that GDF5 alone enhances the conversion of MSCs to fibroblastic cells possessing a phenotype consistent with that of connective-tissue fibroblasts.

Differentiation of Human Amniotic Mesenchymal Stem Cells into Human Anterior Cruciate Ligament Fibroblast Cells by In Vitro Coculture

Anterior cruciate ligament injuries are common in humans, though cellular components of the knee have little regenerative or proliferation potential. This study investigated the differentiation of human amnion-derived mesenchymal stem cells (hAMSCs) into human anterior cruciate ligament fibroblasts (hACLFs) in vitro through induction with bFGF and TGF-β1 with coculture systems. Groups A and B comprised hAMSCs at the 3rd passage cultured with and without bFGF and TGF-β1, respectively; Groups C and D consisted of hAMSCs and hACLFs in monolayer coculture with and without bFGF and TGF-β1, respectively; Groups E and F were composed of hAMSCs and hACLFs in Transwell coculture with and without bFGF and TGF-β1, respectively. Cell morphology and proliferation were recorded. Protein expression and relative mRNA expression were evaluated in each group. Cell proliferation was significantly higher in the induced groups than in the noninduced groups. Protein expression increased over time with the highest expression observed in Group E. mRNA levels were significantly higher in Group E than in other groups. This study is the first to demonstrate the use of the Transwell coculture system for this purpose, and hAMSCs were successfully differentiated into hACLFs. Thus, hAMSCs may be a superior choice for hACLF differentiation via Transwell coculture.

Tendon injuries: Basic science and new repair proposals

Tendons connect muscles to bones, ensuring joint movement. With advanced age, tendons become more prone to degeneration followed by injuries. Tendon repair often requires lengthy periods of rehabilitation, especially in elderly patients. Existing medical and surgical treatments often fail to regain full tendon function.

The development of novel treatment methods has been hampered due to limited understanding of basic tendon biology. Recently, it was discovered that tendons, similar to other mesenchymal tissues, contain tendon stem/progenitor cells (TSPCs) which possess the common stem cell properties.

The current strategies for enhancing tendon repair consist mainly of applying stem cells, growth factors, natural and artificial biomaterials alone or in combination. In this review, we summarise the basic biology of tendon tissues and provide an update on the latest repair proposals for tendon tears.

Cite this article: EFORT Open Rev 2017;2:332-342. DOI: 10.1302/2058-5241.2.160075

Non-invasive imaging of engineered human tumors in the living chicken embryo

The growing interest in engineered tumor models prompted us to devise a method for the non-invasive assessment of such models. Here, we report on bioluminescence imaging (BLI) for the assessment of engineered tumor models in the fertilized chicken egg, i.e, chick chorioallantoic membrane (CAM) assay. One prostate cancer (PC-3) and two osteosarcoma (MG63 and HOS) cell lines were modified with luciferase reporter genes. To create engineered tumors, these cell lines were seeded either onto basement membrane extract (BME) or gelfoam scaffolds, and subsequently grafted in vivo onto the CAM. BLI enabled non-invasive, specific detection of the engineered tumors on the CAM in the living chicken embryo. Further, BLI permitted daily, quantitative monitoring of the engineered tumors over the course of up to 7 days. Data showed that an extracellular matrix (ECM) composed of BME supported growth of reporter gene marked PC-3 tumors but did not support MG63 or HOS tumor growth. However, MG63 tumors engineered on the collagen-based gelfoam ECM showed a temporal proliferation burst in MG63 tumors. Together, the data demonstrated imaging of engineered human cancer models in living chicken embryos. The combination of CAM assay and BLI holds significant potential for the examination of a broad range of engineered tumor models.