Background: Achilles tendinopathy is a common and debilitating condition among female ballet dancers due to the large repetitive loading forces placed on their Achilles tendons during rehearsals and performances. Tendon health problems in females are exacerbated by a lack of understanding about how energy availability influences tendons. Ballet dancers, as aesthetic athletes, are vulnerable to low energy availability and can enter a spectrum disorder, relative energy deficiency in sport, that consists of low energy availability (with or without disordered eating), menstrual cycle dysfunction, and low bone mineral density (BMD). Aims: 1) To investigate the relationship between insufficient caloric intake and Achilles tendon health in pre-professional ballet dancers. 2) To evaluate if symptoms of relative energy deficiency in sport such as low BMD and menstrual irregularity can be matched with Achilles tendon structural damage in pre-professional ballet dancers. 3) To analyze if there is a relationship between BMD and nutrition in pre-professional ballet dancers. Methods: 30 pre-professional ballet dancers were recruited. Over the course of a 16-week training and performance period, the dancers underwent four ultrasound imaging sessions and two MRI sessions investigating their Achilles tendons. They also underwent one full body DXA scan and completed four ASA24 dietary recall surveys. The dancers additionally filled out questionnaires describing their menstrual history and current Achilles tendon health. At the end of the study, dancers were organized into calorie sufficiency groups (sufficient or insufficient). Results: Within both calorie groups, the Achilles tendon was significantly thicker at the end of the study as compared to the start of the study (p=.046). Within both calorie groups, echogenicity was significantly higher at the first two ultrasound imaging sessions than it was at the last two (p<.05). Additionally, the calorie sufficient group's tendons had a significantly higher echogenicity than the calorie insufficient group at the first two ultrasound imaging sessions (p<.05). There were significantly more dancers in the calorie insufficient group that experienced changes to their menstrual cycle (p=.007). Conclusion: Participants in the calorie sufficient group had significantly more hyperechoic tendons than those in the calorie insufficient group at the start of the study, and all participants saw a significant drop in tendon echogenicity halfway through the study. The results of this study suggest that a better understanding of how average caloric intake affects tendon health in dancers is necessary in order to help treat and prevent AT injuries in this dance population.

Tendon function is essential for quality of life, yet the pathogenesis and healing of tendinopathy remains poorly understood compared to other musculoskeletal disorders. The aim of regenerative medicine is to replace traditional tissue and organ transplantation by harnessing the developmental potential of stem cells to restore structure and function to damaged tissues. The recently discovered interdependency of cell phenotype and biophysical environment has created a paradigm shift in cell biology. This dissertation introduces a dynamic in vitro model for tendon function, dysfunction and development, engineered to characterize the mechanobiological relationships dictating stem cell fate decisions so that they may be therapeutically exploited for tendon healing. Cells respond to mechanical deformation via a complex set of behaviors involving force-sensitive membrane receptor activity, changes in cytoskeletal contractility and transcriptional regulation. Effective ex vivo model systems are needed to emulate the native environment of a tissue and to translate cell-matrix forces with high fidelity. A naturally-derived decellularized tendon scaffold (DTS) was invented to serve as a biomimetic tissue culture platform, preserving the structure and function of native extracellular matrix. DTS in concert with a newly designed dynamic mechanical strain system comprises a tendon bioreactor that is able to emulate the three-dimensional topography, extracellular matrix proteins, and mechanical strain that cells would experience in vivo. Mesenchymal stem cells seeded on decellularized tendon scaffolds subject to cyclic mechanical deformation developed strain-dependent alterations in phenotype and measurably improved tissue mechanical properties. The relative tenogenic efficacies of adult stem cells derived from bone marrow, adipose and tendon were then compared in this system, revealing characteristics suggesting tendon-derived mesenchymal stem cells are predisposed to differentiate toward tendon better than other cell sources in this model. The results of the described experiments have demonstrated that adult mesenchymal stem cells are responsive to mechanical stimulation and, while exhibiting heterogeneity based on donor tissue, are broadly capable of tenocytic differentiation and tissue neogenesis in response to specific ultrastructural and biomechanical cues. This knowledge of cellular mechanotransduction has direct clinical implications for how we treat, rehabilitate and engineer tendon after injury. / Ph. D.

Tendon injuries significantly impact quality of life and are often career ending. Mesenchymal stem cell (MSC) therapy is known to augment intrinsic tendon healing, however, little is known of the stem cells endogenous to tendon, the microenvironmental cues that induce tendon differentiation, and whether individual cells in an inflammatory milieu respond differently to these cues. To address these questions, a three-dimensional tenogenesis assay was developed as an efficient and reproducible metric of cellular capacity to differentiate toward tendon. In contrast to more complex assays of tenogenesis, this design incorporates a simple apparatus using commercially available plasticware for the application of uniaxial static strain in in a type I collagen cell-seeded hydrogel construct. Tendon-related gene expression, glycosaminoglycan levels, elongated cell morphologies and parallel cell alignments are enhanced with BMP-12 induction over ten days of culture. This dissertation provides novel insight to the roles of growth factors in MSC tenogenesis. Tendon healing in vivo is dependent on endogenous tendon stem cells (TSC) that mediate the inflammatory response to injury and promote synthesis of collagen and matrix remodeling, among other extracellular processes. Recent evidence suggests that these cells exist on a spectrum of differentiation potencies, and may be differently committed to the tendon fate. Individual stem cells were isolated from the tendon, and their capacities for proliferation, tri-lineage differentiation and tenogenesis were evaluated. Three distinct TSC phenotypes were revealed, and significant, positive correlations were found in quadra-differentiation potency (toward four lineages) and the expression of a strong, composite tendon phenotype. These studies have important implications in the current standard-of-care in regenerative therapies for tendon. Our benchtop tenogenesis assay can be used to determine the therapeutic potential of allogeneic MSC lines and MSCs from novel sources for 'off-the-shelf' treatments. Our study of TSCs lends valuable insight to the diversity of cell phenotypes found in tendon, and the potential contributions of each phenotype to tendon healing and homeostasis. These results further strengthen the status of tendon as a superior source of stem cells for tendon repair. / Ph. D. / Tendons are fibrous, elastic bands of collagen that connect muscles to bones and are essential to movement and proper functioning of the skeletal system. Weight-bearing tendons like the Achilles in humans and superficial digital flexor tendons in horses are particularly prone to damage and degeneration with overuse and/or aging. Bone marrow-derived stem cell treatments have shown promise in the reduction of pain and inflammation, and restoration of native tendon structure and function in cases of severe tendon injuries. However, the roles of stem cells in tendon healing, particularly their ability to transition to cell types native to tendon and integrate with an environment distinct from their own is unknown. Culturing of stem cells in three dimensional (3D) environments has enabled us to identify and understand the biochemical and mechanical signals that trigger stem cell transitions to tendon cells in tendons, but currently available 3D culture systems are complex and inefficient. In this dissertation we have developed a cost-effective and high throughput 3D culture system to assay the potential of stem cells to form tendon cells and composite tendon-like tissues. Toward this, we have also optimized the effects of known tendon proteins on the tendon fate in 3D culture of stem cells. Like most adult tissues, the tendon encompasses an in-house repository of stem cells. Tendon stem cells (TSCs) are primarily responsible for the inflammatory and reparative responses to tendon injury. Recent evidence suggests that TSCs are diverse in character, and differ from each other in their ability to form cells and tissues of fat, bone and cartilage. In this work, we provide evidence that TSCs are also differently committed to forming tendon tissue, and moreover that significant inter-relationships among gene expression patterns in these cells directly contribute to cultural diversity. In sum, our results provide novel insight to the roles of stem cells in tendon healing, particularly their response to subtle changes in their biochemical environment, and the contributions of individual cells in a milieu to a holistic reparative response.

O objetivo deste estudo foi avaliar o efeito dos tempos de aplicação 3, 4 e 5 minutos por ERA do ultrassom terapêutico (UST) na organização das fibras de colágeno em lesão do tendão do calcâneo de ratos. Foram utilizados quarenta ratos machos Wistar, dos quais 32 sofreram tenotomia total do tendão do calcâneo e foram divididos em 5 grupos: GC, sem tenotomia e tratamento; GT, com tenotomia e sem tratamento; UST3, UST4 e UST5 submetidos à tenotomia e tratados com UST nos tempos de 3, 4 e 5 minutos por área de radiação efetiva respectivamente. Os animais foram submetidos à primeira aplicação do UST foi 24 horas após a cirurgia de tenotomia. A irradiação ultrassônica foi aplicada com os seguintes parâmetros: 1 MHz, modo pulsado com 20% do ciclo de trabalho (2 ms de emissão / 8 ms de intervalo), frequência de 100 Hz, 0,5 W / cm² de intensidade e ERA de 0,5 cm². A aplicação foi realizada 1x/dia. Os animais foram sacrificados após a 10ª sessão de tratamento, no 12º dia pós-operatório. Os tendões foram retirados cirurgicamente para análise da organização das fibras colágenas através do método de birrefringência (retardo óptico - OR). As fibras colágenas mostraram melhor agregação e organização no grupo UST3, UST4 e UST5 quando comparado ao GT (p<0.05) e o UST5 apresentou melhor resposta na comparação intergrupos. Conclui-se que o UST, aplicado no tempo de 5 minutos por área de radiação efetiva, apresentou a melhor dose-resposta quanto à organização das fibras colágenas no reparo tecidual de tendões de ratos / The aim of this study was to evaluate the effect of application times 3, 4 and 5 minutes ERA of therapeutic ultrasound in the organization of the collagen fibers in rat calcaneal tendon injury. Forty male Wistar rats were used, of which 32 underwent complete tenotomy of the calcaneal tendon and were divided into 5 groups: GC without tenotomy and treatment; GT tenotomy with and without treatment; UST3, UST4 UST5 and submitted to tenotomy treated with therapeutic ultrasound at times 3, 4 and 5 minutes per effective radiating area respectively. The animals were submitted to the first application of therapy US tenotomy 24 hours after surgery. Ultrasonic irradiation was applied with the following parameters: 1 MHz, pulsed mode at 20% duty cycle (2ms transmission / 8 ms interval), frequency 100 Hz, 0.5 W / cm² intensity and ERA 0.5 cm². The application was performed 1x / day. The animals were sacrificed after the 10th treatment session, on the 12th postoperative day. The tendons were surgically removed for analysis of the organization of the collagen fibers through birefringence method (optical delay - OR). The collagen fibers showed better aggregation and organization in group UST3, UST4 and UST5 when compared to the GT (p <0.05) and UST5 showed better response in the intergroup comparison. We conclude that the UST, applied in time of 5 minutes for effective radiation area, presented the best dose-response as the organization of the collagen fibers in tissue repair of rat tendons

This thesis examined the change in skeletal muscle architecture with contractile force production, the relationship of architecture with muscle strength parameters and if muscle tendinous tissue stiffness determines in vivo explosive strength (i.e. rate of torque development, RTD). Muscle and tendinous tissue adaptations to contrasting strength training regimes, and the potential capacity of these tissues to adapt following chronic strength training were also explored. Quadriceps femoris fascicle length (FL) decreased, while the pennation angle (PA) increased in a curvi-linearly manner from rest to maximal voluntary contraction (MVC) torque. Consequently, effective physiological cross-sectional area (effPCSA) during MVC was 27% greater than at rest, although effPCSA measured at rest and during MVC had similar correlations to maximal strength. In the earliest phase of contraction, FL, but not PA, was negatively related (R2=0.187) to voluntary RTD. Neither FL nor PA was related to maximal isometric or dynamic strength. Muscle-tendon unit (MTU) and patellar tendon (PT) stiffness were unrelated to voluntary and evoked RTD. Relative PT stiffness was also unrelated to relative RTD, although relative MTU stiffness was related to voluntary RTD (25-55%MVT, R2≤0.188) and evoked RTD (5-50%MVT, R2≤0.194). MTU stiffness increased after sustained-contraction (SCT, +21%), though not explosive-contraction strength training (ECT). PT stiffness increased similarly after ECT (+20%) and SCT (+16%), yet neither induced tendon hypertrophy. SCT produced modest muscle (+8%) and aponeurosis (+7%) hypertrophy. Chronic strength trained (CST: >3 years) males had substantially greater muscle and aponeurosis size, but similar tendon size as untrained controls (UNT) and short-term (12 weeks) strength trained (STT) individuals. Between these groups, at the highest common force, MTU stiffness was indifferent, while PT stiffness was similarly greater in STT and CST than UNT. These results suggest FL and PA have little influence on muscle strength and tendon stiffness has no influence on RTD. Maximum strength negated any qualitative influence of MTU stiffness on in vivo RTD. Component MTU tissues (muscle-aponeurosis vs. external tendon) adapt differentially depending on the strength training regime. Specifically, free tendon appeared to adapt to high magnitude loading, while loading duration is also an important stimulus for the muscle-aponeurosis. However, chronic strength training was not concordant with greater higher force MTU stiffness, and does not further increase higher force PT stiffness beyond the adaptations that occur after 12 weeks of strength training. Finally, no evidence was found for tendon hypertrophy in response to strength training.

Orientador: Edson Rosa Pimentel / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-21T05:39:03Z (GMT). No. of bitstreams: 1 Aro_AndreaAparecidade_D.pdf: 5514361 bytes, checksum: 938312e7fcf5c6bdd9bba11064c61b15 (MD5) Previous issue date: 2012 / Resumo: A utilização de extratos vegetais com atividades farmacológicas pode ser promissora no tratamento de lesões tendíneas, considerando a presença de princípios ativos que estimulam a síntese de componentes da matriz extracelular (MEC). Portanto, o presente estudo teve como objetivo investigar após 7, 14 e 21 dias da lesão, os efeitos da aplicação tópica dos extratos de A. vera e A. chica sobre tendões parcialmente transeccionados de ratos. Os grupos tratados com o extrato da A. chica foram denominados A7, A14 e A21 (controles S7, S14 e S21), e após tratamento com a A. vera foram denominados Av7, Av14 e Av21 (controles B7, B14 e B21). Foram realizadas análises bioquímicas tais como Western blotting, zimografia e dosagens de hidroxiprolina, de proteínas não colagênicas (PNCs) e de glicosaminoglicanos (GAGs); assim como análises estruturais, ultraestruturais e funcionais. Após aplicação do extrato da A. chica, a concentração de PNCs foi menor em A7 e a de hidroxiprolina foi maior em A7 e A21, em relação aos controles. Considerando a MMP-9, menor quantidade foi detectada no grupo A14 comparado ao grupo S14. As isoformas latente, intermediária e ativa da MMP-2 foram observadas em todos os grupos, porém maiores quantidades das isoformas latente e intermediária foram encontradas em A21. Os resultados de Western blotting mostraram menor quantidade de colágenos tipos I e III em A7 comparado ao controle. Maior quantidade de dermatan sulfato (DS) foi detectada em A14, e quantidade inferior de DS e condroitin sulfato (CS) foi observada em A21 comparada ao S21. As medidas de birrefringência detectaram maior organização das fibras de colágeno no grupo A21 em relação ao controle, e as análises ultraestruturais mostraram muitos fragmentos de colágeno na região transeccionada nos grupos S7 e A7. A análise do CatWalk mostrou que os animais tratados com A. chica, exibiram maior pressão de contato das patas durante a marcha no 7° dia. Considerando a aplicação de A. vera, foi observada em SDS-PAGE banda menos intensa referente ao colágeno em Av14, confirmado por Western blotting. O grupo Av21 apresentou maior concentração de PNCs comparado ao seu controle. Na dosagem de hidroxiprolina, os grupos Av7 e Av14 apresentaram maiores concentrações, ao passo que Av21 apresentou valor inferior ao controle. O grupo Av14 apresentou maior concentração de GAGs sulfatados e menor quantidade de DS em relação ao controle. Menor quantidade de MMP-9 foi encontrada em Av14, e menores quantidades das isoformas latente e intermediária da MMP-2 foram observadas em Av7 e Av14 em relação aos controles. Maior quantidade da isoforma ativa da MMP-2 foi observada em Av21 comparado a B21. As medidas de birrefringência detectaram maior organização das fibras de colágeno em Av14 em relação ao controle. Ao passo que as medidas de dicroísmo linear realizadas nos cortes corados com azul de toluidina, mostraram menor organização dos GAGs em Av14 comparado ao controle. Nossa conclusão é que a aplicação tópica dos extratos da A. chica e da A. vera é efetiva na síntese e organização de componentes da MEC durante o processo de reparo / Abstract: The use of plant extracts bearing pharmacological activities may be promising in the treatment of tendon injuries, considering the presence of active principles that stimulate the synthesis of extracellular matrix components (ECM). Therefore, this study aimed to investigate after 7, 14 and 21 days of injury, the effects of topical application of extracts of A. vera and A. chica on the healing of partially transected tendons of rats. The groups treated with the extract of A. chica were called A7, A14 and A21 (controls S7, S14 and S21), and after treatment with A. vera were called Av7, Av14 and Av21 (controls B7, B14 and B21). Biochemical analysis were performed such as Western blotting, zymography and quantification of hydroxyproline, non-collagenous proteins (NCPs) and glycosaminoglycans (GAGs); as well as structural, ultrastructural and functional analysis. After application of the extract of A. chica, the concentration of non-collagenous proteins (NCPs) was lower in A7 and hydroxyproline was higher in A7 and A21, compared to controls. Considering the MMP-9, lower amount was found in A14 compared to S14. The latent, intermediate and active isoforms of MMP-2 were observed in all groups, but larger quantities of latent and intermediate isoforms were found in A21. The results of Western blotting showed a lower amount of collagen types I and III compared to the control A7. Higher amount of dermatan sulphate (DS) was detected in A14 and lower amounts of DS and chondroitin sulfate (CS) were observed in A21 compared to S21. The birefringence measurements showed a higher organization of collagen fibers in the A21 group compared to control, and ultrastructural analysis showed many fragments of collagen in the transected region of groups S7 and A7. Analysis of the Catwalk showed that animals treated with A. chica exhibited a higher contact pressure of the legs during walking on the 7th day. Considering the application of A. vera, less intense band related to collagen was observed on SDS-PAGE in Av14, confirmed by Western blotting. The group Av21had a higher concentration of NCPs compared to the control. In the dosage of hydroxyproline, Av7 and Av14 groups had higher concentrations in relation to their controls, while Av21 showed lower value than control group. The group Av14 had a higher concentration of glycosaminoglycans and lower amount of DS compared to control. Lower amount of MMP-9 was found in Av14, and lower amounts of intermediate and latent isoforms of MMP-2 were observed in Av7 and Av14 compared to controls. A higher amount of the active isoform of MMP-2 was observed in Av21 compared to B21. The birefringence measurements showed a higher organization of collagen fibers in Av14 compared to control. While linear dichroism measurements performed on sections stained with toluidine blue, showed lower organization of glycosaminoglycans in Av14 compared to control. Our conclusion is that the topical application of extracts of A. chica and A. vera is effective in the synthesis and organization of ECM components during the repair process / Doutorado / Biologia Celular / Doutor em Biologia Celular e Estrutural

Le tendon transmet les forces musculaires aux os et permet le mouvement. C'est un tissucomplexe et organisé, formé de cellules et d’une matrice extracellulaire (fibres collagènes,élastiques et substance fondamentale). Les fibres lui confèrent son élasticité et résistance et lasubstance fondamentale sa viscosité.La tendinopathie est souvent lié au sport, de morbidité élevée qui affecte laperformance des sportifs. Elle associe dégénérescence, douleur, rigidité et oedème local.L’imagerie quantifie et qualifie les changements morphologiques du tendon. L’homéostasietendineuse et sa physiopathologie restent peu connues, mais un changement des liaisons desfibrilles lors de la cicatrisation diminue sa résistance.L’objectif de l’étude est: mettre en place un modèle de tendinopathie chirurgicale chezla chèvre avec suivi clinique transposable (homme et cheval); développer un dispositifd’évaluation du comportement mécanique des tendons; et valider la chèvre comme modèleanimal pour l’étude de la tendinopathie. L’étude a été faite sur 84 jours avec un suivi cliniqueet échographique suivi d’un test de traction.La chèvre est un ongulé facile à héberger et manipuler. La technique chirurgicalepermet la résection de quelques fibres causant une lésion identifiable par échographie et dessymptômes cliniques. La grande variabilité du comportement mécanique ne se corrèle pas aupoids, morphologie des animaux ou section transversale du ses tendon, ce qui complique laréduction de l’effective. Notre modèle semble pouvoir être utilisé pour évaluer des traitementsde tendinopathies destinés à l’homme et/ou au cheval. Ce que n’exclue pas sondéveloppement pour renforcer sa pertinence / Tendons transmit muscles forces to bone and allow movement. It is a complexorganized tissue, composed by few cells and an extracellular matrix (collagen fibers, elasticfibers, and a ground substance. Fibers give to tendon its elastic characteristic and resistanceand ground substance its viscosity.Tendinopathy is a medical problem associated with sport, with a high morbidity whichaffects performance. It is an association of degeneration, pain, stiffness and local edema.Imaging can be used to quantify and qualify the changes in the morphology of the tendon.The tendon homeostasis and physiopathology remain poorly understood, but a change at theconnections of the fibrils, decreasing its strength.The purpose of this study is: development of surgical model of induced localtendinopathy in goats with clinical follow up transposable for humans and horses;development of a device to evaluate the mechanical properties of tendons, and demonstratethat the goat is a good experimental animal model for the study of tendinopathy. The studyhas been performed in 84 days with a clinical follow up, US imaging and tensile test.Goat is an ungulate easy to house and handle. The modified splitting allows easy andreproducible resection of some tendon fibers with an identifiable lesion in US imaging andclinical symptoms. The variability of mechanical behavior is not correlated with"macroscopic" aspects (weight, animal morphology or cross sectional area), thus reducing theeffective is difficult. However, our model appears in the state, can be used to evaluatetreatments for human and horse’s tendinopathy. The development of our model couldstrengthen its relevance.

O objetivo deste estudo foi avaliar o efeito dos tempos de aplicação 3, 4 e 5 minutos por ERA do ultrassom terapêutico (UST) na organização das fibras de colágeno em lesão do tendão do calcâneo de ratos. Foram utilizados quarenta ratos machos Wistar, dos quais 32 sofreram tenotomia total do tendão do calcâneo e foram divididos em 5 grupos: GC, sem tenotomia e tratamento; GT, com tenotomia e sem tratamento; UST3, UST4 e UST5 submetidos à tenotomia e tratados com UST nos tempos de 3, 4 e 5 minutos por área de radiação efetiva respectivamente. Os animais foram submetidos à primeira aplicação do UST foi 24 horas após a cirurgia de tenotomia. A irradiação ultrassônica foi aplicada com os seguintes parâmetros: 1 MHz, modo pulsado com 20% do ciclo de trabalho (2 ms de emissão / 8 ms de intervalo), frequência de 100 Hz, 0,5 W / cm² de intensidade e ERA de 0,5 cm². A aplicação foi realizada 1x/dia. Os animais foram sacrificados após a 10ª sessão de tratamento, no 12º dia pós-operatório. Os tendões foram retirados cirurgicamente para análise da organização das fibras colágenas através do método de birrefringência (retardo óptico - OR). As fibras colágenas mostraram melhor agregação e organização no grupo UST3, UST4 e UST5 quando comparado ao GT (p<0.05) e o UST5 apresentou melhor resposta na comparação intergrupos. Conclui-se que o UST, aplicado no tempo de 5 minutos por área de radiação efetiva, apresentou a melhor dose-resposta quanto à organização das fibras colágenas no reparo tecidual de tendões de ratos / The aim of this study was to evaluate the effect of application times 3, 4 and 5 minutes ERA of therapeutic ultrasound in the organization of the collagen fibers in rat calcaneal tendon injury. Forty male Wistar rats were used, of which 32 underwent complete tenotomy of the calcaneal tendon and were divided into 5 groups: GC without tenotomy and treatment; GT tenotomy with and without treatment; UST3, UST4 UST5 and submitted to tenotomy treated with therapeutic ultrasound at times 3, 4 and 5 minutes per effective radiating area respectively. The animals were submitted to the first application of therapy US tenotomy 24 hours after surgery. Ultrasonic irradiation was applied with the following parameters: 1 MHz, pulsed mode at 20% duty cycle (2ms transmission / 8 ms interval), frequency 100 Hz, 0.5 W / cm² intensity and ERA 0.5 cm². The application was performed 1x / day. The animals were sacrificed after the 10th treatment session, on the 12th postoperative day. The tendons were surgically removed for analysis of the organization of the collagen fibers through birefringence method (optical delay - OR). The collagen fibers showed better aggregation and organization in group UST3, UST4 and UST5 when compared to the GT (p <0.05) and UST5 showed better response in the intergroup comparison. We conclude that the UST, applied in time of 5 minutes for effective radiation area, presented the best dose-response as the organization of the collagen fibers in tissue repair of rat tendons

Until today equine flexor tendon injuries represent a major entity within the scope of equine medicine. Since their response to treatment is often poor, they remain an important therapeutic challenge for researchers as well as clinicians. It is of great importance to emphasize the tedious nature of the natural healing response within the tendon. This inevitably ends in a repair including scar tissue formation which is inferior to the original tendon tissue especially regarding its biomechanical properties and therefore, predisposing to reinjury. The wide range of treatment strategies for tendinopathies or suspensory ligament pathologies reflects the tenacious nature of the disease as well as lack of universal therapeutic effectiveness. The use of regenerative treatment strategies opened up new prospects for the treatment of tendon injuries and showed promising results. However, research efforts are still warranted to objectively asses their efficacy. At the same time basic science concerning aetiopathogenesis and pathophysiology of equine tendon injuries is still a factor of major importance regarding the development of effective strategies for therapy and prevention. Recently, the use of regenerative medicine has rapidly increased, progressively upstaging traditional surgical treatment options for equine tendon or suspensory ligament pathologies. The aim of the present study on the one hand was the analysis of the results and evaluation of the surgical treatment options percutaneous desmoplasty and osteostixis at the origin of the suspensory ligament by means of retrospective clinical case studies. On the other hand, success of these techniques was evaluated depending on different success parameters. These included the age of the horse, duration of lameness prior to surgery, observance of a given controlled exercise program by the owners and ground conditions. In case of percutaneous osteostixis also presence of a hindlimb conformation predisposing for proximal suspensory desmitis was investigated. Part of the first retrospective study examining percutaneous desmoplasty (tendon splitting) as a single surgical treatment were 71 horses (n=85). Desmoplasty was performed at the origin of the suspensory ligament (41 cases), inferior check ligament (21 cases), superficial flexor tendon (13 cases), branch of the suspensory ligament (6 cases) or at the body of the suspensory ligament (4 cases). The second retrospective study investigated the implementation of percutaneous osteostixis at the origin of the suspensory ligament in 14 horses (n=16). Percutaneous osteostixis was carried out alone (1 case), in conjunction with desmoplasty at the origin of the suspensory ligament (7 cases) and combined with desmoplasty, neurectomy of the deep branch of the lateral plantar nerve and plantar fasciotomy (8 cases). Concerning percutaneous osteostixis overall successful outcome was achieved in 11 horses (78.6 %) respectively 12 cases (75.0 %). The various evaluated parameters showed no statistically significant influence on the success of treatment. For percutaneous desmoplasty overall successful outcome was achieved in 55 cases (67.9 %, n=81). Observance of the controlled exercise program showed a statistically significant influence on the success of treatment (n=79, p<0.05). In summary the present paper illustrates the important role of percutaneous desmoplasty in nowadays` management of tendon and suspensory ligament injuries in the horse. Furthermore, percutaneous osteostixis proved to be a valuable alternative to conservative treatment for osseous as well as soft tissue injuries at the origin of the suspensory ligament, specifically in case of recurring lesions not responding to desmoplasty alone. Therefore, despite the rapidly increasing significance of regenerative treatment strategies these traditional surgical approaches should not fall into oblivion for they still have unchanged effectiveness. Especially postoperative implementation of a controlled and gradually increasing exercise program represents an essential part of rehabilitation, highlighted by the significant connection with successfull outcome of desmoplasty shown in the present paper, as a key factor greatly contributing to the success of each form of therapy:1 EINLEITUNG 1 2 LITERATURÜBERSICHT 3 2.1 Einführung in die Thematik der equinen Sehnenerkrankungen 3 2.1.1 Anatomische Grundlagen 3 2.1.2 Histologie der Sehne 4 2.1.3 Biomechanik der Sehne 7 2.1.4 Ätiologie und Pathogenese von Sehnenerkrankungen 11 2.1.5 Mechanismus der Sehnenheilung 20 2.1.6 Grundsätzliches zur Therapie von Sehnenerkrankungen 29 2.1.7 Definitionen 32 2.2 Das perkutane Sehnensplitting beim Pferd 33 2.2.1 Grundprinzip und Indikationen 33 2.2.2 Bedeutung des postoperativen Managements 35 2.3 Einsatzgebiete der perkutanen Osteostixis im Bereich des Fesselträgerursprungs 38 2.3.1 Allgemeines zur Methodik der Osteostixis 38 2.3.2 Anatomische Verhältnisse im Bereich des FTRU 40 2.3.3 Klinisches Erscheinungsbild der PSD 42 2.3.4 Sonographische Untersuchung 43 2.3.5 Röntgenologische Untersuchung 46 2.3.6 Szintigraphische Untersuchung 47 2.3.7 Magnetresonanztomographische Untersuchung 48 2.3.8 Innervation des FTRU 49 2.3.9 Diagnostische Anästhesien 49 2.3.10 Begleitoperationen zur Osteostixis: Faziotomie, Neurektomie und Splitting 50 2.3.11 Knochenschmerz 55 2.3.12 Prädispositionen für die Entwicklung einer PSD 55 3 TIERE, MATERIAL UND METHODEN 57 3.1 Sehnensplitting 57 3.1.1 Material 57 3.1.1.1 Einschlusskriterien 57 3.1.1.2 Alters-, Geschlechts-, Nutzungs- und Rassenverteilung 57 3.1.1.3 Erkrankte Gliedmaßen und Strukturen 57 3.1.1.4 Begleitende Eingriffe 58 3.1.1.5 Vorbehandlung 58 3.1.1.6 Begleitende Behandlung 58 3.1.1.7 Folgeinformationen 58 3.1.2 Methoden 58 3.1.2.1 Diagnostik 58 3.1.2.1.1 Klinische Lahmheitsuntersuchung 58 3.1.2.1.2 Befunderhebung mittels bildgebender Verfahren 59 3.1.2.2 Durchführung 60 3.1.2.2.1 Methodik des Sehnensplittings 60 3.1.2.2.2 Postoperatives Management 61 3.1.2.2.3 Kontrolliertes Bewegungsprogramm 61 3.1.2.3 Statistik 62 3.2. Osteostixis 63 3.2.1 Material 63 3.2.1.1 Einschlusskriterien 63 3.2.1.2 Alters-, Geschlechts-, Nutzungs- und Rassenverteilung 64 3.2.1.3 Erkrankte Gliedmaßen und begleitende Eingriffe 64 3.2.1.4 Vorbehandlung 64 3.2.1.5 Begleitende Behandlung 64 3.2.1.6 Folgeinformationen 64 3.2.2 Methoden 65 3.2.2.1 Diagnostik 65 3.2.2.1.1 Klinische Lahmheitsuntersuchung 65 3.2.2.1.2 Befunderhebung mittels bildgebender Verfahren 66 3.2.2.2 Durchführung 66 3.2.2.2.1 Methodik der perkutanen Osteostixis sowie der Begleitoperationen 66 3.2.2.2.2 Postoperatives Management 68 3.2.2.2.3 Kontrolliertes Bewegungsprogramm 68 3.2.2.3 Statistik 69 4 ERGEBNISSE 70 4.1 Ergebnisse Sehnensplitting 70 4.1.1 Sehnenübergreifende Ergebnisse 70 4.1.2 Sehnenspezifische Ergebnisse 72 4.1.2.1 Splitting des Fesselträgerkörpers (FTRK, 4 Fälle) 72 4.1.2.2 Splitting des Fesselträgerschenkels (FTRS, 6 Fälle) 72 4.1.2.3 Splitting der oberflächlichen Beugesehne (OBS, 13 Fälle) 73 4.1.2.4 Splitting des Unterstützungsbandes der tiefen Beugesehne (UB-TBS, 21 Fälle) 74 4.1.2.5 Splitting des Fesselträgerursprungs (FTRU, 41 Fälle) 75 4.2 Ergebnisse Osteostixis 78 4.2.1 Fallbetrachtungen Osteostixis 79 4.2.1.1 Osteostixis ohne Begleitoperationen (1 Fall) 79 4.2.1.2 Osteostixis mit Splitting des FTRU (7 Fälle) 79 4.2.1.3 Osteostixis mit Splitting sowie Fasziotomie und Neurektomie (8 Fälle) 81 5 DISKUSSION 84 5.1. Anmerkungen zum Studienaufbau 84 5.2 Beurteilung der Ergebnisse des perkutanen Sehnensplittings 84 5.3 Beurteilung der Ergebnisse der perkutanen Osteostixis 88 5.4 Schlussfolgerungen 91 6 ZUSAMMENFASSUNG 93 7 SUMMARY 95 8 LITERATURVERZEICHNIS 97 9 DANKSAGUNG 110

In this study, we examined how hill running affects the Achilles tendon, which is a common location for injuries in runners. Twenty females ran for 10 min on three randomly selected grades (-6%, 0%, +6%). Achilles tendon (AT) cross-sectional area (CSA) was imaged using Doppler ultrasound and peak vertical forces were analyzed using high-speed (240 Hz) videography. A metabolic cart and gas analyzer ensured a similar metabolic cost across grades. Data were analyzed using a forward selection regression. Results showed a decrease in AT CSA from pre-run to post-run (p = .0001). Peak vertical forces were different across grades (p = .0001) with the largest occurring during downhill running and smallest during uphill running. The results suggest that the Achilles tendon is affected by running and a decrease in CSA appears to be a normal response. The AT CSA does not differ between grade conditions when metabolic cost of running is matched, suggesting an adaptive effect of the AT. Coaches and athletes can use this knowledge to develop workout protocols that transition runners to downhill running and allow them to adapt to these greater forces.