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1.
Adv Healthc Mater ; 10(20): e2100741, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34494401

RESUMO

Tendons are among the most mechanically stressed tissues of the body, with a functional core of type-I collagen fibers maintained by embedded stromal fibroblasts known as tenocytes. The intrinsic load-bearing core compartment of tendon is surrounded, nourished, and repaired by the extrinsic peritendon, a synovial-like tissue compartment with access to tendon stem/progenitor cells as well as blood monocytes. In vitro tendon model systems generally lack this important feature of tissue compartmentalization, while in vivo models are cumbersome when isolating multicellular mechanisms. To bridge this gap, an improved in vitro model of explanted tendon core stromal tissue (mouse tail tendon fascicles) surrounded by cell-laden collagen hydrogels that mimic extrinsic tissue compartments is suggested. Using this model, CD146+ tendon stem/progenitor cell and CD45+ F4/80+ bone-marrow derived macrophage activity within a tendon injury-like niche are recapitulated. It is found that extrinsic stromal progenitors recruit to the damaged core, contribute to an overall increase in catabolic ECM gene expression, and accelerate the decrease in mechanical properties. Conversely, it is found that extrinsic bone-marrow derived macrophages in these conditions adopt a proresolution phenotype that mitigates rapid tissue breakdown by outwardly migrated tenocytes and F4/80+ "tenophages" from the intrinsic tissue core.


Assuntos
Traumatismos dos Tendões , Tendões , Animais , Colágeno , Macrófagos , Camundongos , Tenócitos
2.
Nat Commun ; 12(1): 5012, 2021 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-34408142

RESUMO

Tendon self-renewal is a rare occurrence because of the poor vascularization of this tissue; therefore, reconstructive surgery using autologous tendon is often performed in severe injury cases. However, the post-surgery re-injury rate is relatively high, and the collection of autologous tendons leads to muscle weakness, resulting in prolonged rehabilitation. Here, we introduce an induced pluripotent stem cell (iPSC)-based technology to develop a therapeutic option for tendon injury. First, we derived tenocytes from human iPSCs by recapitulating the normal progression of step-wise narrowing fate decisions in vertebrate embryos. We used single-cell RNA sequencing to analyze the developmental trajectory of iPSC-derived tenocytes. We demonstrated that iPSC-tenocyte grafting contributed to motor function recovery after Achilles tendon injury in rats via engraftment and paracrine effects. The biomechanical strength of regenerated tendons was comparable to that of healthy tendons. We suggest that iPSC-tenocytes will provide a therapeutic option for tendon injury.


Assuntos
Tendão do Calcâneo/lesões , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes Induzidas/transplante , Traumatismos dos Tendões/terapia , Tenócitos/citologia , Tenócitos/transplante , Tendão do Calcâneo/citologia , Tendão do Calcâneo/fisiopatologia , Animais , Autorrenovação Celular , Terapia Baseada em Transplante de Células e Tecidos , Células Cultivadas , Humanos , Masculino , Ratos , Ratos Endogâmicos F344 , Recuperação de Função Fisiológica , Traumatismos dos Tendões/fisiopatologia
3.
J Orthop Surg Res ; 16(1): 413, 2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34193225

RESUMO

BACKGROUND: The network of intermediate filament proteins underlying the inner nuclear membrane forms the nuclear lamin. A- and B-type lamins are the major components of the nuclear lamina. Lamins function in many nuclear activities. The role of lamin A and transcription factors (NF-kB) as anti-apoptotic is well documented. Recently, lamin A has also been considered as a mechanosensor protein that is able to maintain nuclear integrity from mechanical insults. We aimed to verify how lamin A expression varies in healthy cuff cells and in those with different-sized tears where various mechanical stresses are present. METHODS: Forty-three patients with rotator cuff tear (RCT) [23M-20F, mean age (SD): 63.5 (6.1)] were enrolled. Tissue samples excised from the most medial point of tear margins were analyzed for lamin A expression by immunohistochemistry. Controls were represented by samples obtained by normal supraspinatus tendons excised from patients submitted to reverse shoulder prosthesis implant [8M-7F, mean age (SD): 67.9 (7.1)]. The intensity of staining was graded, and an H-score was assigned. Statistical analysis was performed. RESULTS: Our study revealed a moderate intensity of lamin A in the healthy cuff tendons, a higher expression of this protein in the small tears, and a significant decrease of lamin A with increasing tear size (p < 0.0001). CONCLUSIONS: Our study emphasizes the importance of early repair of small RCTs since nuclear stability is maintained, and the cellular function is protected by lamin A overexpression. High re-tear of massive cuff repair could be due to cellular apoptosis and nuclear modifications induced by lamin A lack. LEVEL OF EVIDENCE: III.


Assuntos
Lamina Tipo A/metabolismo , Lesões do Manguito Rotador/metabolismo , Manguito Rotador/citologia , Tenócitos/metabolismo , Idoso , Apoptose , Estudos de Casos e Controles , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Lesões do Manguito Rotador/patologia
4.
Int J Mol Sci ; 22(9)2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-34066472

RESUMO

The mechanosensitive gene tenomodulin (Tnmd) is implicated in tendon maturation and repair. However, the mechanism by which mechanical loading regulates Tnmd's expression and its role in tenocyte migration is yet to be defined. Here, we show that Tnmd and migration were upregulated in uniaxial cyclic stress-stimulated tenocytes. The knockdown of Tnmd reduced cell migration in the presence and absence of mechanical loading, suggesting that Tnmd is involved in tenocyte migration. Moreover, the treatment of stress-stimulated tenocytes with the actin inhibitor latrunculin (Lat A), histone acetyltransferase inhibitor anacardic acid (ANA), or histone demethylases inhibitor GSK-J4 suppressed Tnmd expression and tenocyte migration. These results show that actin stress fiber formation and chromatin decondensation regulates Tnmd expression, which might then regulate tenocyte migration. Thus, this study proposes the involvement of the actin and chromatin mechanotransduction pathway in the regulation of Tnmd and reveals a novel role of Tnmd in tenocyte migration. The identification of Tnmd function in tenocyte migration provides insight into the molecular mechanisms involved in Tnmd-mediated tendon repair.


Assuntos
Actinas/metabolismo , Movimento Celular , Montagem e Desmontagem da Cromatina , Proteínas de Membrana/metabolismo , Estresse Mecânico , Tenócitos/citologia , Tenócitos/metabolismo , Animais , Células Cultivadas , Cromatina/metabolismo , Proteínas de Membrana/genética , Ratos Sprague-Dawley , Fibras de Estresse/metabolismo , Regulação para Cima/genética
5.
BMC Musculoskelet Disord ; 22(1): 519, 2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34090401

RESUMO

BACKGROUND: Dehydroepiandrosterone (DHEA), an adrenal steroid, has a protective role against diabetes. This study aimed to investigate the in vitro and in vivo protective effects of DHEA against high glucose-induced oxidative stress in tenocytes and tendons. METHODS: Tenocytes from normal Sprague-Dawley rats were cultured in low-glucose (LG) or high-glucose (HG) medium with or without DHEA. The experimental groups were: control group (LG without DHEA), LG with DHEA, HG without DHEA, and HG with DHEA. Reactive oxygen species (ROS) production, apoptosis, and messenger RNA (mRNA) expression of NADPH oxidase (NOX) 1 and 4, and interleukin-6 (IL-6) were determined. Further, diabetic rats were divided into a control group and a DHEA-injected group (DHEA group). NOX1 and NOX4 protein expression and mRNA expression of NOX1, NOX4, IL-6, matrix metalloproteinase (MMP)-2, tissue inhibitors of matrix metalloproteinase (TIMP)-2, and type I and III collagens in the Achilles tendon were determined. RESULTS: In rat tenocytes, DHEA decreased the expression of NOX1 and IL-6, ROS accumulation, and apoptotic cells. In the diabetic rat Achilles tendon, NOX1 protein expression and mRNA expression of NOX1, IL-6, MMP-2, TIMP-2, and type III collagen were significantly lower while type I collagen expression was significantly higher in the DHEA group than in the control group. CONCLUSIONS: DHEA showed antioxidant and anti-inflammatory effects both in vitro and in vivo. Moreover, DHEA improved tendon matrix synthesis and turnover, which are affected by hyperglycemic conditions. DHEA is a potential preventive drug for diabetic tendinopathy.


Assuntos
Diabetes Mellitus Experimental , Tenócitos , Animais , Células Cultivadas , Desidroepiandrosterona/farmacologia , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/tratamento farmacológico , Glucose/toxicidade , Estresse Oxidativo , Ratos , Ratos Sprague-Dawley
6.
Sci Rep ; 11(1): 12451, 2021 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-34127759

RESUMO

For research on tendon injury, many different animal models are utilized; however, the extent to which these species simulate the clinical condition and disease pathophysiology has not yet been critically evaluated. Considering the importance of inflammation in tendon disease, this study compared the cellular and molecular features of inflammation in tenocytes of humans and four common model species (mouse, rat, sheep, and horse). While mouse and rat tenocytes most closely equalled human tenocytes' low proliferation capacity and the negligible effect of inflammation on proliferation, the wound closure speed of humans was best approximated by rats and horses. The overall gene expression of human tenocytes was most similar to mice under healthy, to horses under transient and to sheep under constant inflammatory conditions. Humans were best matched by mice and horses in their tendon marker and collagen expression, by horses in extracellular matrix remodelling genes, and by rats in inflammatory mediators. As no single animal model perfectly replicates the clinical condition and sufficiently emulates human tenocytes, fit-for-purpose selection of the model species for each specific research question and combination of data from multiple species will be essential to optimize translational predictive validity.


Assuntos
Traumatismos dos Tendões/imunologia , Tendões/patologia , Tenócitos/imunologia , Animais , Células Cultivadas , Colágeno/metabolismo , Modelos Animais de Doenças , Matriz Extracelular/metabolismo , Feminino , Cavalos , Humanos , Inflamação/imunologia , Inflamação/patologia , Camundongos , Cultura Primária de Células , Ratos , Ovinos , Especificidade da Espécie , Traumatismos dos Tendões/patologia , Tendões/citologia , Tendões/imunologia , Tenócitos/metabolismo
7.
J Biol Chem ; 297(1): 100819, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34029590

RESUMO

Collagen-derived hydroxyproline (Hyp)-containing peptides have a variety of biological effects on cells. These bioactive collagen peptides are locally generated by the degradation of endogenous collagen in response to injury. However, no comprehensive study has yet explored the functional links between Hyp-containing peptides and cellular behavior. Here, we show that the dipeptide prolyl-4-hydroxyproline (Pro-Hyp) exhibits pronounced effects on mouse tendon cells. Pro-Hyp promotes differentiation/maturation of tendon cells with modulation of lineage-specific factors and induces significant chemotactic activity in vitro. In addition, Pro-Hyp has profound effects on cell proliferation, with significantly upregulated extracellular signal-regulated kinase phosphorylation and extracellular matrix production and increased type I collagen network organization. Using proteomics, we have predicted molecular transport, cellular assembly and organization, and cellular movement as potential linked-network pathways that could be altered in response to Pro-Hyp. Mechanistically, cells treated with Pro-Hyp demonstrate increased directional persistence and significantly increased directed motility and migration velocity. They are accompanied by elongated lamellipodial protrusions with increased levels of active ß1-integrin-containing focal contacts, as well as reorganization of thicker peripheral F-actin fibrils. Pro-Hyp-mediated chemotactic activity is significantly reduced (p < 0.001) in cells treated with the mitogen-activated protein kinase kinase 1/2 inhibitor PD98059 or the α5ß1-integrin antagonist ATN-161. Furthermore, ATN-161 significantly inhibits uptake of Pro-Hyp into adult tenocytes. Thus, our findings document the molecular basis of the functional benefits of the Pro-Hyp dipeptide in cellular behavior. These dynamic properties of collagen-derived Pro-Hyp dipeptide could lead the way to its application in translational medicine.


Assuntos
Movimento Celular/efeitos dos fármacos , Dipeptídeos/farmacologia , Homeostase/efeitos dos fármacos , Integrina beta1/metabolismo , Pseudópodes/metabolismo , Tendões/citologia , Envelhecimento , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Matriz Extracelular/efeitos dos fármacos , Matriz Extracelular/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Camundongos , Pseudópodes/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Tenócitos/citologia , Tenócitos/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos
8.
FASEB J ; 35(6): e21618, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33982337

RESUMO

Tendons are dense connective tissues that transmit muscle forces to the skeleton. After adult injury, healing potential is generally poor and dominated by scar formation. Although the immune response is a key feature of healing, the specific immune cells and signals that drive tendon healing have not been fully defined. In particular, the immune regulators underlying tendon regeneration are almost completely unknown due to a paucity of tendon regeneration models. Using a mouse model of neonatal tendon regeneration, we screened for immune-related markers and identified upregulation of several genes associated with inflammation, macrophage chemotaxis, and TGFß signaling after injury. Depletion of macrophages using AP20187 treatment of MaFIA mice resulted in impaired functional healing, reduced cell proliferation, reduced ScxGFP+ neo-tendon formation, and altered tendon gene expression. Collectively, these results show that inflammation is a key component of neonatal tendon regeneration and demonstrate a requirement for macrophages in effective functional healing.


Assuntos
Proliferação de Células , Inflamação/terapia , Macrófagos/imunologia , Regeneração , Traumatismos dos Tendões/terapia , Tenócitos/citologia , Cicatrização , Animais , Animais Recém-Nascidos , Modelos Animais de Doenças , Feminino , Inflamação/imunologia , Inflamação/patologia , Masculino , Camundongos , Traumatismos dos Tendões/imunologia , Traumatismos dos Tendões/patologia , Tenócitos/fisiologia
10.
Int J Mol Sci ; 22(6)2021 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-33803624

RESUMO

A central part of the complement system, the anaphylatoxin C5a was investigated in this study to learn its effects on tenocytes in respect to understanding the potential expression of other crucial complement factors and pro-inflammatory mediators involved in tendinopathy. Human hamstring tendon-derived tenocytes were treated with recombinant C5a protein in concentrations of 25 ng/mL and 100 ng/mL for 0.5 h (early phase), 4 h (intermediate phase), and 24 h (late phase). Tenocytes survival was assessed after 24 h stimulation by live-dead assay. The gene expression of complement-related factors C5aR, the complement regulatory proteins (CRPs) CD46, CD55, CD59, and of the pro-inflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6 was monitored using qPCR. Tenocytes were immunolabeled for C5aR and CD55 proteins. TNFα production was monitored by ELISA. Tenocyte survival was not impaired through C5a stimulation. Interestingly, the gene expression of C5aR and that of the CRPs CD46 and CD59 was significantly reduced in the intermediate and late phase, and that of TNFα only in an early phase, compared to the control group. ELISA analysis indicated a concomitant not significant trend of impaired TNFα protein synthesis at 4 h. However, there was also an early significant induction of CD55 and CD59 mediated by 25 ng/mL anaphylatoxin C5a. Hence, exposure of tenocytes to C5a obviously evokes a time and concentration-dependent response in their expression of complement and pro-inflammatory factors. C5a, released in damaged tendons, might directly contribute to tenocyte activation and thereby be involved in tendon healing and tendinopathy.


Assuntos
Complemento C5a/metabolismo , Proteínas do Sistema Complemento/metabolismo , Tenócitos/metabolismo , Adulto , Antígenos CD55/metabolismo , Ativação do Complemento , Regulação da Expressão Gênica , Humanos , Interleucina-6/genética , Interleucina-6/metabolismo , Masculino , Receptor da Anafilatoxina C5a/metabolismo , Fatores de Tempo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo
11.
Inflamm Res ; 70(4): 495-507, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33772629

RESUMO

INTRODUCTION: The present in vitro study was undertaken to learn about the effects of leukocytes on tenocytes in respect to complement regulation simulating an inflammatory scenario of the traumatized tissue. METHODS: Human hamstring tendon-derived tenocyte monolayers were co-cultured indirectly with human leukocytes (either Peripheral Blood Mononuclear Cells [PBMCs] or neutrophils) using a transwell system with/without (+ /wo) 10 ng/ml tumor necrosis factor α (TNFα) for 4 and 24 h. Tenocyte and leukocyte cell survival was assessed by live-dead assay. Tenocyte gene expression of TNFα, the anaphylatoxin receptor C5aR and the cytoprotective complement regulatory proteins (CRP) CD46, CD55 and CD59 was monitored using qPCR. TNFα was detected in the culture supernatants using ELISA. RESULTS: C5aR gene expression was significantly induced by TNFα after 4 h, but impaired in the presence of leukocytes + TNFα after 24 h. At 4 h, PBMCs activated by TNFα induced the CRP CD46 gene expression. However, CD55 was significantly suppressed after 24 h by neutrophils + /woTNFα. Leukocytes activated by TNFα decreased also significantly the gene expression of the more downstream acting CRP CD59 after 4 h. TNFα gene expression and ELISA analysis revealed an amplified TNFα expression/release in tenocyte co-cultures with PBMC + /woTNFα, probably contributing to complement regulation. CONCLUSION: TNFα might represent a crucial soluble mediator exerting diverse time-dependent effects on tenocyte complement regulation.


Assuntos
Antígenos CD/metabolismo , Leucócitos Mononucleares/metabolismo , Receptor da Anafilatoxina C5a/metabolismo , Tenócitos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Adulto , Antígenos CD/genética , Células Cultivadas , Técnicas de Cocultura , Proteínas do Sistema Complemento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Receptor da Anafilatoxina C5a/genética , Fator de Necrose Tumoral alfa/genética
12.
J Biosci ; 462021.
Artigo em Inglês | MEDLINE | ID: mdl-33737496

RESUMO

Current treatment systems for tendon injuries are very few and do not ensure complete cure. This is a serious health concern for sports persons and the aged population. It is known that the nano- or microsized particles of natural products such as jeera/cumin seed (Cuminum cyminum) has been used traditionally as a home remedy for the treatment of tendon injuries. Nevertheless, these particles are likely to perform better due to their smaller size, increased absorption and local delivery in conjunction with nanotechnology. In this context, the major objective of this study was to synthesize silver-capped nanoparticles using aqueous extract of Cuminum cyminum (CCE) and to assess their in vitro non-cytotoxic effect with the perspective of clinical application to enhance tendon tissue regeneration. The presence of phytochemicals in CCE was studied by qualitative and quantitative methods. Cuminum cyminum nanoparticles (CCNP) were synthesized by the bioreduction method using silver nitrate and the particles were characterized by X-ray diffraction analysis (XRD), Fourier Transform Infra Red Spectroscopy (FTIR), Zeta potential measurement and scanning electron microscopy (SEM). The antioxidant effect of the particles was studied using total antioxidant activity and reducing power assay. Simultaneously, primary Tenocytes were isolated from rabbit Achilles tendon by collagenase and dispase digestion/treatment and characterized for Type 1 collagen. Further, in vitro non-cytotoxicity of the CCNP in direct contact with L929 mouse fibroblast cells and primary Tenocytes, respectively, was evaluated by MTT assay. Physico-chemical characterizations confirmed the formation and stability of the nanosize of CCNP with antioxidant property. Again, MTT assay confirmed the non-cytotoxicity of CCNP with L929 fibroblasts and primary Tenocytes. CCNP may be attributed as an ideal candidate for therapeutic application towards a faster restoration of worn-out/injured tendon tissue confronted by the geriatric and athlete communities.


Assuntos
Cuminum/química , Nanopartículas Metálicas/química , Tenócitos/efeitos dos fármacos , Animais , Antioxidantes/química , Antioxidantes/farmacologia , Difusão Dinâmica da Luz , Fibroblastos/efeitos dos fármacos , Química Verde , Nanopartículas Metálicas/uso terapêutico , Camundongos , Extratos Vegetais/química , Coelhos , Sementes/química , Prata , Tenócitos/fisiologia
13.
Sci Rep ; 11(1): 1516, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452334

RESUMO

Reciprocity between cells and their surrounding extracellular matrix is one of the main drivers for cellular function and, in turn, matrix maintenance and remodelling. Unravelling how cells respond to their environment is key in understanding mechanisms of health and disease. In all these examples, matrix anisotropy is an important element, since it can alter the cell shape and fate. In this work, the objective is to develop and exploit easy-to-produce platforms that can be used to study the cellular response to natural proteins assembled into diverse topographical cues. We demonstrate a robust and simple approach to form collagen substrates with different topographies by evaporating droplets of a collagen solution. Upon evaporation of the collagen solution, a stain of collagen is left behind, composed of three regions with a distinct pattern: an isotropic region, a concentric ring pattern, and a radially oriented region. The formation and size of these regions can be controlled by the evaporation rate of the droplet and initial collagen concentration. The patterns form topographical cues inducing a pattern-specific cell (tenocyte) morphology, density, and proliferation. Rapid and cost-effective production of different self-agglomerated collagen topographies and their interfaces enables further study of the cell shape-phenotype relationship in vitro. Substrate topography and in analogy tissue architecture remains a cue that can and will be used to steer and understand cell function in vitro, which in turn can be applied in vivo, e.g. in optimizing tissue engineering applications.


Assuntos
Colágeno/fisiologia , Matriz Extracelular/fisiologia , Engenharia Tecidual/métodos , Anisotropia , Diferenciação Celular , Forma Celular , Células Cultivadas , Colágeno/metabolismo , Humanos , Tendões/metabolismo , Tenócitos/metabolismo , Tecidos Suporte
14.
Jt Dis Relat Surg ; 32(1): 152-161, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33463431

RESUMO

OBJECTIVES: This study aims to compare the effects of systemic and local applications of tranexamic acid (TXA) on tendon healing using a rat Achilles tendon injury model. PATIENTS AND METHODS: Thirty-six adult male albino Wistar rats (aging 3-4 months; weighing 350 to 400 g) were used in this study conducted between December 2019 and January 2020. The Achilles tendon was performed bilateral tenotomy and surgically repaired. Postoperatively, 1 mL of TXA was administered to each leg locally in the local group, whereas 2 mL of TXA was intraperitoneally administered in the systemic group. The control group was left untreated. Half of the rats were sacrificed on Day 15 and the other half on Day 30. Tendon healing was evaluated with the Bonar and the Movin scoring systems and immunohistochemical methods. RESULTS: The systemic group had the highest Bonar and Movin scores on Day 15. All groups exhibited tendon healing on Day 30, with no significant differences among the groups. The tenocyte morphology was found to be more impaired in both TXA groups on Day 30 (p=0.013). Ground substance scores were lower in the systemic group on Day 30 (p=0.028). The fiber structure and arrangement scores were higher in the systemic group on Day 15 (p=0.007 and p=0.032). Immunohistochemical analyses showed that galectin-3 values exhibited a significant difference in all groups on Day 30 (p=0.020). In all groups, it was determined that type I collagen values showed an increasing trend on Day 30, compared to the values on Day 15, whereas type III collagen values showed a decreasing trend. CONCLUSION: Our results demonstrated that local and systemic use of TXA does not impair tendon healing. Although advanced studies are needed, our study suggests that TXA application reduces the development of fibrosis.


Assuntos
Tendão do Calcâneo/lesões , Antifibrinolíticos/farmacologia , Traumatismos dos Tendões/cirurgia , Ácido Tranexâmico/farmacologia , Cicatrização/efeitos dos fármacos , Tendão do Calcâneo/patologia , Tendão do Calcâneo/cirurgia , Animais , Colágeno Tipo I/metabolismo , Colágeno Tipo III/metabolismo , Modelos Animais de Doenças , Masculino , Ratos , Ratos Wistar , Tenócitos , Tenotomia
15.
J Anat ; 238(3): 527-535, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33070316

RESUMO

The three-dimensional ultrastructure of the tendon is complex. Two main cell types are classically supported: elongated tenocytes and ovoid tenoblasts. The existence of resident stem/progenitor cells in human and equine tendons has been demonstrated, but their location and relationship to tenoblasts and tenocytes remain unclear. Hence, in this work, we carried out an ultrastructural study of the equine superficial digital flexor tendon. Although the fine structure of tendons has been previously studied using electron microscopy, the presence of telocytes, a specific type of interstitial cell, has not been described thus far. We show the presence of telocytes in the equine inter-fascicular tendon matrix near blood vessels. These telocytes have characteristic telopodes, which are composed of alternating dilated portions (podoms) and thin segments (podomers). Additionally, we demonstrate the presence of the primary cilium in telocytes and its ability to release exosomes. The location of telocytes is similar to that of tendon stem cells. The telocyte-blood vessel proximity, the presence of primary immotile cilia and the release of exosomes could have special significance for tendon homeostasis.


Assuntos
Cavalos/anatomia & histologia , Telócitos/ultraestrutura , Tendões/ultraestrutura , Tenócitos/ultraestrutura , Animais
16.
Tissue Eng Part A ; 27(15-16): 1023-1036, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33045937

RESUMO

The tenocyte niche contains biochemical and biophysical signals that are needed for tendon homeostasis. The tenocyte phenotype is correlated with cell shape in vivo and in vitro, and shape-modifying cues are needed for tenocyte phenotypical maintenance. Indeed, cell shape changes from elongated to spread when cultured on a flat surface, and rat tenocytes lose the expression of phenotypical markers throughout five passages. We hypothesized that tendon gene expression can be preserved by culturing cells in the native tendon shape. To this end, we reproduced the tendon topographical landscape into tissue culture polystyrene, using imprinting technology. We confirmed that the imprints forced the cells into a more elongated shape, which correlated with the level of Scleraxis expression. When we cultured the tenocytes for 7 days on flat surfaces and tendon imprints, we observed a decline in tenogenic marker expression on flat but not on imprints. This research demonstrates that native tendon topography is an important factor contributing to the tenocyte phenotype. Tendon imprints therefore provide a powerful platform to explore the effect of instructive cues originating from native tendon topography on guiding cell shape, phenotype, and function of tendon-related cells.


Assuntos
Biomimética , Tenócitos , Animais , Células Cultivadas , Fenótipo , Ratos , Tendões , Engenharia Tecidual
17.
Knee Surg Sports Traumatol Arthrosc ; 29(6): 1862-1871, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32860523

RESUMO

PURPOSE: Intra-articular administration of tranexamic acid (TXA) in orthopaedic arthroplasty and arthroscopic procedures has become increasingly common over the past decade. However, several recent reports have shown that TXA has the potential to be cytotoxic to cartilage, tendon and synovium. Our aim was to review the literature for evidence of toxic effects from TXA exposure to intra-articular tissue. METHODS: A scoping review methodology was used to search for studies assessing the toxic effects of TXA exposure to intra-articular tissues. MEDLINE, EMBASE, SCOPUS and The Cochrane Library were searched. Relevant information was extracted and synthesis of the retrieved data followed a basic content analytical approach. RESULTS: A total of 15 laboratory studies were retrieved. No clinical studies reporting a toxic effect of TXA on intra-articular tissue were identified in our search. Studies were analysed according to species of origin, tissue of origin and study setting (in vitro, ex vivo, or in vivo). There was increasing cytotoxicity to chondrocytes, tenocytes, synoviocytes and periosteum-derived cells with TXA concentrations beyond 20 mg/ml. Monolayer cell cultures appear more susceptible to TXA exposure, than three-dimensional and explant culture models. In vivo studies have not demonstrated a major toxic effect. CONCLUSIONS: Current evidence suggests a dose-dependent toxic effect on cartilage, tendon, and synovial tissue. Concentrations of 20 mg/ml or less are expected to be safe. There is a significant body of evidence to suggest the need for caution with intraarticular administration of TXA. There is a need for further human clinical trials in order to clarify the long-term safety of TXA topical application.


Assuntos
Antifibrinolíticos/efeitos adversos , Artroscopia , Condrócitos/efeitos dos fármacos , Sinoviócitos/efeitos dos fármacos , Tenócitos/efeitos dos fármacos , Ácido Tranexâmico/efeitos adversos , Antifibrinolíticos/administração & dosagem , Humanos , Injeções Intra-Articulares , Periósteo/efeitos dos fármacos , Ácido Tranexâmico/administração & dosagem
18.
J Cell Physiol ; 236(5): 3991-4007, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33151579

RESUMO

Musculoskeletal interfaces are naturally hypoxic. An understanding of key interactions occurring between different cell populations and their environment is critical for native tissue recapitulation. Here, an enthesis coculture model (preosteoblasts and tendon cells) was used to understand the influence of hypoxia (5% O2 ) and osteogenic medium (OM) supplementation in cells' phenotype modulation. In single cultures, preosteoblasts were found to undergo osteogenic impairment, while tendon cells underwent a maturation process through extracellular matrix (ECM) rescue. When in co-culture, hypoxia and osteoinduction promoted a temporal chondro/osteogenic pathway activation, as observed by an early deposition of cartilaginous ECM associated with HIF1A stabilization and RUNX2 activation, and later hypertrophic differentiation resulting from HIF2A translocation and SOX9 activation. Moreover, the presence of OM under hypoxia was shown to influence the extracellular ROS/HIF1A interplay. Overall, this study revealed a link between biochemical factors and cell-cell crosstalk, providing a molecular framework for hypoxic control and modulation of cells' fate toward enthesis-like phenotypes.


Assuntos
Condrócitos/metabolismo , Matriz Extracelular/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Osteogênese , Adulto , Idoso , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Biomarcadores/metabolismo , Hipóxia Celular , Condrogênese , Meios de Cultura , Regulação da Expressão Gênica , Glicosaminoglicanos/metabolismo , Humanos , Pessoa de Meia-Idade , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Estabilidade Proteica , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição SOX9/metabolismo , Transdução de Sinais , Tenócitos/metabolismo , Fatores de Tempo
19.
J Orthop Res ; 39(7): 1561-1571, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-32478872

RESUMO

Current knowledge gaps on tendon tissue healing can partly be ascribed to the limited availability of physiologically relevant culture models. An unnatural extracellular matrix, high serum levels and random cell morphology in vitro mimic strong vascularization and lost cell elongation in pathology, and discord with a healthy, in vivo cell microenvironment. The thereby induced phenotypic drift in tendon-derived cells (TDCs) compromises the validity of the research model. Therefore, this research quantified the extracellular matrix (ECM)-, serum-, and cell morphology-guided phenotypic changes in tendon cells of whole tendon fascicle explants with intact ECM and TDCs cultured in a controlled microenvironmental niche. Explanted murine tail tendon fascicles were cultured in serum-rich or serum-free medium and phenotype was assessed using transcriptome analysis. Next, phenotypic marker gene expression was measured in in vitro expanded murine tail TDCs upon culture in serum-rich or serum-free medium on aligned or random collagen I patterns. Freshly isolated fascicles or TDCs served as native controls. In both systems, the majority of tendon-specific genes were similarly attenuated in serum-rich culture. Strikingly, 1-week serum-deprived culture-independent of cell morphology-converged TDC gene expression toward native levels. This study reveals a dynamic serum-responsive tendon cell phenotype. Extracting fascicles or TDCs from their native environment causes large changes in cellular phenotype, which can be limited and even reversed by serum deprivation. We conclude that serum-derived factors override matrix-integrity and cell morphology cues and that serum-deprivation stimulates a more physiological microenvironment for in vitro studies.


Assuntos
Técnicas de Cultura de Células , Tenócitos/fisiologia , Animais , Meios de Cultura , Camundongos Endogâmicos C57BL , Fenótipo , Soro , Tendões/citologia
20.
Dev Growth Differ ; 63(1): 38-46, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33270251

RESUMO

Human pluripotent stem cells (PSCs) are used as a platform for therapeutic purposes such as cell transplantation therapy and drug discovery. Another motivation for studying PSCs is to understand human embryogenesis and development. All cell types that make up the body tissues develop through defined trajectories during embryogenesis. For example, paraxial mesoderm is considered to differentiate into several cell types including skeletal muscle cells, chondrocytes, osteocytes, dermal fibroblasts, and tenocytes. Tenocytes are fibroblast cells that constitute the tendon. The step-wise narrowing fate decisions of paraxial mesoderm in the embryo have been modeled in vitro using PSCs; however, deriving tenocytes from human-induced PSCs and their application in cell therapy have long been challenging. PSC-derived tenocytes can be used for a source of cell transplantation to treat a damaged or ruptured tendon due to injury, disorder, or aging. In this review, we discuss the latest research findings on the use of PSCs for studying the biology of tenocyte development and their application in therapeutic settings.


Assuntos
Células-Tronco Pluripotentes/citologia , Tenócitos/citologia , Diferenciação Celular , Humanos
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