Effect of exercise on age-related changes in collagen fibril diameter distributions in the common digital extensor tendons of young horses

OBJECTIVE: To determine whether specific treadmill exercise regimens would accelerate age-related changes in collagen fibril diameter distributions in the common digital extensor tendon (CDET) of the forelimbs of young Thoroughbreds. ANIMALS: 24 female Thoroughbreds. PROCEDURE: Horses were trained for 18 weeks (6 horses; short term) or 18 months (5 horses; long term) on a high-speed treadmill; 2 age-matched control groups (6 horses/group) performed walking exercise only. Horses were (mean +/- SD) 24 +/- 1 months and 39 +/- 1 months old at termination of the short-term and long-term regimens, respectively. Midmetacarpal CDET specimens were obtained and processed for transmission electron microscopy. Diameter and area of at least 1,000 collagen fibrils/specimen were measured by use of computerized image analysis. Mass-average diameter (MAD) of collagen fibrils and collagen fibril index were calculated for each horse. RESULTS: Collagen fibril MAD for the older horses was significantly less than that for the younger horses. Exercise did not significantly affect fibril diameter or distributions in either age group, and collagen fibril index did not differ significantly between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Age-related reduction in collagen fibril MAD agreed with findings for other tendons and species. Training did not accelerate age-related change in the CDET in contrast to a reported decrease in collagen fibril MAD in the superficial digital flexor tendon of horses trained long term. Our results support the concept that the functionally distinct nature of the CDET and superficial digital flexor tendon in horses results in fundamentally different responses to high-speed exercise regimens.     

Age-related changes to the molecular and cellular components of equine flexor tendons.

Specific tendons show a high incidence of partial central core rupture which is preceded by degeneration. In the performance horse, the superficial digital flexor tendon (SDFT) is most often affected. We have described previously the molecular changes that are associated with degeneration in the central core region of the equine SDFT. The pathophysiological mechanism leading to change in synthetic activity of central zone cells in degenerated tendons is not known. In this study, we test the hypothesis that ageing results in matrix composition changes within the central zone of the SDFT. Extracellular matrix composition and cellularity were analysed in equine SDFTs collected from Thoroughbred horses and compared with a flexor tendon which rarely shows degenerative change and subsequent injury (deep digital flexor tendon, DDFT). Data were examined for age-related changes to central and peripheral zone tissue of the SDFT and DDFT. Ageing in both tendons (SDFT and DDFT) resulted in a significant increase in collagen-linked fluorescence and a decrease in cellularity in the DDFT but not the SDFT. The central zone tissue from the SDFT had a significantly higher proportion of type III collagen than the peripheral zone of the tendon. The highest level of type III collagen was found in the central zone tissue of the SDFT from the older group of horses and this may represent the early stages of a degenerative change. Collagen content did not differ between the 2 flexor tendons; however, there were differences in collagen type and organisation. The SDFT had a higher type III collagen content, higher levels of the mature trifunctional collagen crosslink hydroxylysylpyridinoline, lower total chondroitin sulphate equivalent glycosaminoglycan content, smaller diameter collagen fibrils and a higher cellularity than the DDFT. In conclusion, differences in macromolecular composition exist between the flexor tendons and ageing contributes to a tendon specific change in composition.     

Effects of exercise on the diameter of collagen fibrils in the central core and periphery of the superficial digital flexor tendon in foals

OBJECTIVE: To determine the effects of exercise on collagen fibril diameter distribution in the superficial digital flexor tendon (SDFT) of foals. ANIMALS: 43 Dutch Warmblood foals. PROCEDURE: From 1 week until 5 months of age, group-1 foals (n = 14) were housed in stalls and not exercised, group-2 foals (14) were housed in stalls but were exercised, and group-3 foals (15) were maintained at pasture. Biopsy specimens were collected from the SDFT at 2 months, and 8 foals in each group were euthanatized at 5 months. Remaining foals were housed together in a loose stall and paddock until euthanatized at 11 months. After euthanasia, specimens were collected from the SDFT; all specimens were analyzed by use of electron microscopy. Collagen fibrillar index (CFI), mass average diameter (MAvD), and area dependent diameter (ADD) were compared among groups. RESULTS: Exercise-related differences in fibril distribution were not detected among groups at 2 months. At 5 months, ADD in peripheral specimens was significantly greater in group 1 than group 3. At 11 months, MAvD in core specimens was significantly less in group 3, compared with the other groups. However, in peripheral specimens, MAvD was significantly less in groups 2 and 3. CONCLUSIONS AND CLINICAL RELEVANCE: Collagen fibril restructuring in the SDFT of foals is in part an exercise-driven process. Withholding exercise may cause a delay in fibril development that can be partially overcome by increasing exercise at a later age. Exercise type may also affect remodeling of the SDFT in foals.     

Monitoring the fate of autologous and allogeneic mesenchymal progenitor cells injected into the superficial digital flexor tendon of horses: preliminary study

Autologous mesenchymal progenitor cells (MPCs) purified from bone marrow aspirates are being used in the treatment of superficial digital flexor tendon (SDFT) injuries in the horse with promising results. In this study the fate of autologous and allogeneic MPCs following injection into the SDFT was monitored by stable transfection of MPCs with green fluorescent protein (GFP). Small lesions were created manually in one forelimb SDFT of 2 horses and injected with autologous MPCs, allogeneic MPCs or bone marrow supernatant alone. Post mortem examinations performed after 10 or 34 days revealed GFP labelled cells located mainly within injected lesions, but with a small proportion integrated into the crimp pattern of adjacent healthy areas of tendon. Furthermore, there was no visible cell mediated immune response to allogeneic MPCs in either of the host horses.     

Characterization and clinical application of mesenchymal stem cells from equine umbilical cord blood

Tendinitis of the superficial digital flexor tendon (SDFT) is a significant cause of lameness in horses; however, recent studies have shown that stem cells could be useful in veterinary regenerative medicine. Therefore, we isolated and characterized equine umbilical cord blood mesenchymal stem cells (eUCB-MSCs) from equine umbilical cord blood obtained from thoroughbred mares during the foaling period. Horses that had tendinitis of the SDFT were treated with eUCB-MSCs to confirm the therapeutic effect. After eUCB-MSCs transplantation, the core lesion in the SDFT was found to decrease. These results suggest that transplantation using eUCB-MSCs could be another source of cell treatment.     

Microwave thermography: a non-invasive technique for investigation of injury of the superficial digital flexor tendon in the horse.

Microwave thermographs were recorded from 77 normal horses. In 51% the lowest temperature was recorded in the mid-metacarpal region, and in 41% it was in the distal metacarpal region. The mean temperature of the normal limbs ranged from 25.04 to 37.4 degrees C. Maximum temperature differences between symmetrical points in both forelimbs ranged from 0 to 5.33 degrees C and differences in mean limb temperatures between both forelimbs ranged from 0 to 2.91 degrees C. In 48 horses with acute (less than 4 weeks' duration) injury of the superficial digital flexor tendon (SDFT) (36 unilateral, 12 bilateral) and 12 horses with acute injury of the soft tissues of the palmar metacarpal region other than the SDFT (all unilateral) 66% of forelimbs had acute SDFT injury, and 50% of those with other soft tissue injuries, had elevations of the temperature in the mid- or distal metacarpal region. Abnormal values for mean limb temperature, difference in mean limb temperature and maximum temperature difference between locations in opposite forelimbs were detected in 75% of the horses with SDFT injury and in only 16% of the horses with other soft tissue injury. The sensitivity of microwave thermography for the detection of SDFT injury was 81% and the specificity 74%. When 30 horses in National Hunt training were examined weekly for 5 weeks, 2 horses sustained SDFT injury during that period. The microwave thermographs recorded from these 2 horses, at 1 and 2 weeks before the onset of clinical signs, were abnormal. However, 16 horses which did not develop tendon injury also displayed thermographic abnormalities.     

Influence of topically applied cold treatment on core temperature and cell viability in equine superficial digital flexor tendons

OBJECTIVE: To determine rate and degree of cooling for the superficial digital flexor tendon (SDFT) during a standard cryotherapy application in horses and evaluate in vitro effects of cooling on survival of tendon cells. SAMPLE POPULATION: 6 limbs of 5 adult horses and cultured cells obtained from SDFT of 3 adult horses during necropsy. PROCEDURE: In vivo data were acquired by use of a thermocouple temperature probe inserted into the SDFT of a forelimb of each standing sedated horse. After baseline temperatures were recorded, a commercial compression splint with circulating coolant was placed on each selected limb, which was then exposed to cold treatment for 60 minutes. Temperatures were recorded at 30-second intervals. Mean minimum core temperature was calculated and used to design a protocol for in vitro cold treatment of cells. Specimens were obtained from the SDFT of horses during necropsy; tendon cells were cultured in suspension and exposed to 1-hour of cold treatment that mimicked the in vivo procedure. Viability of cells after cold treatment was compared with viability of cells maintained at body temperature. RESULTS: After 1 hour of cold treatment, SDFT core temperature was reduced by a mean of 21.8 degrees C, reaching a mean minimum temperature of 10 degrees C. Viability did not differ significantly between cold-treated and control cells. CONCLUSION AND CLINICAL RELEVANCE: Results indicated that topical application of cryotherapy significantly reduced core SDFT temperature in standing sedated horses. Temperatures achieved in vivo during cold treatment were not detrimental to the in vitro viability of tendon cells.     

Injuries of the calcaneal insertions of the superficial digital flexor tendon in 19 horses

Reasons for performing study: Injuries of the calcaneal insertions of the superficial digital flexor tendon and their relationship to displacement of the tendon from the calcaneus have not previously been reported. Objectives: To describe findings made on clinical cases with disruption of the calcaneal insertions of the superficial digital flexor tendon (SDFT) including observations on their role in horses with unstable subluxation of the tendon. To describe novel surgical techniques and the results of treatment. Hypotheses: Disruption of the calcaneal insertions of the SDFT is associated with lameness and distension of the calcaneal bursa. Unstable displacement of the SDFT from the calcaneus is a more complex injury than incomplete disruption of one of its calcaneal insertions. Methods: The case records and diagnostic images of horses with lesions involving the calcaneal insertions of the SDFT, which were confirmed by endoscopic evaluation of calcaneal bursa between 2005 and 2009, were reviewed. Results: Nineteen horses were identified including 7 that had unstable displacement of the tendon from the calcaneus. Following endoscopic surgery, 9 of 12 horses with stable tendons and 6 of 7 horses with unstable displaced SDFTs returned to work. Conclusion: Tearing of the calcaneal insertions of the SDFT is associated with lameness and distension of the calcaneal bursa; endoscopic removal of the torn tissue carries a good prognosis. Horses with unstable displacement of the tendon have also disruption of the tendon fibrocartilage cap. Removal of this results in stable subluxation and can return horses to athletic activity. Both lesions can be detected by preoperative ultrasonography. Potential relevance: Tearing of the calcaneal insertions of the SDFT should be included in the differential diagnoses of lame horses with distended calcaneal bursae. Tearing of the tendon fibrocartilage cap in horses with unstable displacement of the SDFT is a plausible explanation of the clinical features of the injury and explains previously unreliable results of reconstructive surgeries. Subtotal resection is a technically demanding technique but appears to offer an improved prognosis.     

Equine adipose-tissue derived mesenchymal stem cells and platelet concentrates: their association in vitro and in vivo

Equine mesenchymal stem cells (MSC) are of particular interest both for basic research and for the therapeutic approach to musculoskeletal diseases in the horse. Their multilineage differentiation potential gives them the capability to contribute to the repair of tendon, ligament and bone damage. MSCs are also considered a promising therapeutic aid in allogeneic cell transplantation, since they show low immunogenicity and immunomodulating functions.Adipose tissue-derived adult equine stem cells (AdMSC) can be isolated, expanded in vitro and then inoculated into the damaged tissue, eventually in the presence of a biological scaffold. Here we report our preliminary experience with adipose-derived mesenchymal stem cells in allogeneic cell-therapy of tendonitis in the horse. MSCs, derived from visceral adipose tissue, were grown in the presence of autologous platelet lysate and characterized for their differentiation and growth potential. Expanded AdMSC were inoculated into the damaged tendon after their dispersion in activated platelet-rich plasma (PRP), a biological scaffold that plays an important role in maintaining cells in defect sites and contributes to tissue healing. Fourteen out of sixteen treated horses showed a functional recovery and were able to return to their normal activity.     

Association between race history and risk of superficial digital flexor tendon injury in Thoroughbred racehorses

OBJECTIVE: To determine whether race history, including the number of races and total race distance, was associated with risk of superficial digital flexor tendon (SDFT) injury in Thoroughbred racehorses in Japan. DESIGN: Matched case-control study. ANIMALS: 515 Thoroughbred racehorses (case horses) that sustained an SDFT injury during training or racing in Japan during 2002 and 951 horses (control horses) without SDFT injury that were matched with case horses on the basis of age and month of the latest race. PROCEDURE: Variables related to race history were compared between case and control horses by means of conditional logistic regression. RESULTS: The odds of SDFT injury increased as mean race distance and mean body weight at race time increased. Compared with females that had never competed in steeplechase races, males regardless of steeplechase race history and females that had competed in steeplechase races had higher odds of SDFT injury. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that longer mean distance per race, heavier mean body weight at race time, steeplechase experience, and sex (male) increased the risk of SDFT injury in Thoroughbred racehorses.     

The relationship between in vivo limb and in vitro tendon mechanics after injury: a potential novel clinical tool for monitoring tendon repair

Reasons for performing the study: Highly prevalent superficial digital flexor tendon (SDFT) injury results in compromised tendon function through fibrosis and high frequency of re‐injury due to altered biomechanical function. This study investigated the consequences of SDF tendinopathy on limb mechanics in relation to the mechanical properties of injured tendon. Objectives: To develop and validate a noninvasive in vivo assessment of tendon mechanics to investigate the effect of recent SDFT injury on limb stiffness index, providing an objective method to assess quality of healing. Hypotheses: Limb stiffness index would reduce as a consequence of SDFT injury and progressively increase during tendon healing and correlate with in vitro mechanical properties of the respective SDFTs. Methods: Kinematic analysis was performed at walk in 10 horses that had sustained career‐ending SDFT injury. Stiffness index was derived from limb force recorded via a series of force plates and measurement of change in metacarpophalangeal joint angle using 3D motion analysis software. Horses were subjected to euthanasia 7 months after injury, the SDFTs removed and subjected to nondestructive in vitro mechanical testing. Results: Limb stiffness index was reduced following SDFT injury in comparison with the contralateral limb and increased during the convalescent period, approximating that of the contralateral limb by 7 months post injury. There was a significant positive correlation between in vivo limb stiffness index and in vitro SDFT stiffness. Clinical relevance: The ability to assess and monitor SDFT mechanical competence through limb stiffness measurement techniques in horses recovering from SDFT injury and the possibility of corroborating this with functional tendon healing may permit a more objective and accurate assessment of optimal tendon repair in the horse. This technique may be a useful method for assessing the efficacy of treatment regimens for tendinopathy and could be utilised to predict time to safe return to performance or re‐injury.     

Equine adipose-tissue derived mesenchymal stem cells and platelet concentrates: their association in vitro and in vivo

Equine mesenchymal stem cells (MSC) are of particular interest both for basic research and for the therapeutic approach to musculoskeletal diseases in the horse. Their multilineage differentiation potential gives them the capability to contribute to the repair of tendon, ligament and bone damage. MSCs are also considered a promising therapeutic aid in allogeneic cell transplantation, since they show low immunogenicity and immunomodulating functions.Adipose tissue-derived adult equine stem cells (AdMSC) can be isolated, expanded in vitro and then inoculated into the damaged tissue, eventually in the presence of a biological scaffold. Here we report our preliminary experience with adipose-derived mesenchymal stem cells in allogeneic cell-therapy of tendonitis in the horse. MSCs, derived from visceral adipose tissue, were grown in the presence of autologous platelet lysate and characterized for their differentiation and growth potential. Expanded AdMSC were inoculated into the damaged tendon after their dispersion in activated platelet-rich plasma (PRP), a biological scaffold that plays an important role in maintaining cells in defect sites and contributes to tissue healing. Fourteen out of sixteen treated horses showed a functional recovery and were able to return to their normal activity.     

The effect of recombinant equine growth hormone on the biomechanical properties of healing superficial digital flexor tendons in horses

OBJECTIVE: To evaluate the effect of recombinant equine growth hormone (rEGH) on the in vitro biomechanical properties of healing superficial digital flexor tendon (SDFT) in horses. STUDY DESIGN: Completely randomized design. SAMPLE POPULATION: Twelve Standardbred horses, 3 to 7 years of age, with ultrasonographically normal forelimb SDFT. METHODS: One week after induction of collagenase (2,000 U) induced superficial flexor tendonitis, horses were randomly divided into groups of 6. One group was administered intramuscular rEGH (10 microg/kg/day for 1 week, then 20 microg/kg/day for 5 weeks), whereas the other group (control subjects) were administered an equivalent volume of saline (0.9% NaCl) solution. At the end of this 6-week treatment, horses were killed and one forelimb SDFT from each horse was harvested for biomechanical testing under uniaxial tension. Results were analyzed using an unpaired Student's t test; significance was set at P 相似文献   

Relationship between the ultrasonographic findings of suspected superficial digital flexor tendon injury and the prevalence of subsequent severe superficial digital flexor tendon injuries in Thoroughbred horses: a retrospective study

The onset of severe injury to the superficial digital flexor tendon (SDFT) is extremely difficult to predict from slight changes in ultrasonographic findings in cases with no apparent clinical signs. This study investigated the relationship between an increased cross-sectional area (CSA) or edema in the subcutaneous tissue around the tendon and the subsequent onset of severe SDFT injury in Thoroughbred racehorses. Horses were classified into three groups based on ultrasound diagnosis (USD) findings: Group A included cases with enlarged tendons; Group B included cases with tendons of normal size but with prominent edema in the peritendinous tissue; and Group C (control group) included cases with no abnormal USD findings. The incidence of subsequent severe tendon injury was significantly higher in the horses in Groups A (25.7%, 28/101) and B (28.3%, 65/212) than in those in Group C (4.9%, 2/41). There were no significant differences in the median period and the median number of races from the first examination to the subsequent tendon injury between Groups A (140 days, 1 race) and B (120 days, 1 race). The results of this study revealed that horses with increased CSA and peritendinous edema are likely to suffer a subsequent severe tendon injury. Also, these two USD findings, i.e., increased CSA and peritendinous edema, indicate the risk of onset of severe SDFT injury.     

Equine embryonic stem‐like cells and mesenchymal stromal cells have different survival rates and migration patterns following their injection into damaged superficial digital flexor tendon

Reasons for performing study: Injury to the superficial digital flexor tendon (SDFT) is common in racing and sport horses and poor tendon regeneration leads to high reinjury rates. Autologous mesenchymal stromal cells (MSCs) are being used clinically to improve tendon regeneration but they have some practical limitations. Embryonic stem cells (ESCs) may overcome these limitations but their fate following injection into the damaged SDFT is unknown. Objective: To inject MSCs and ESCs into distinct areas of damage in the SDFT and monitor their survival over a 3 month period. Methods: MSCs and ESCs expressing different reporter genes were injected into separate sites of mechanically induced damage in SDFTs. Cell survival and distribution were examined post mortem after 10, 30, 60 and 90 days and host immune responses determined. Results: Neither MSCs nor ESCs produced signs of cell‐mediated immune response or tumour formation. ESC survival was high and numbers were maintained at a constant level over 90 days. ESCs were present at all sites of damage. In contrast, MSCs showed <5% survival at 10 days and numbers declined over the course of the experiment. MSCs were detected only at the site into which they were injected. Conclusions: ESCs survived in greater numbers than MSCs in the damaged tendon and did not induce an immune response, or form tumours at the injection sites in the 90 day time period studied. ESCs also demonstrated an ability to migrate to other areas of damage within the same tendon, whereas MSCs did not. Potential relevance: ESCs can be used allogeneically, therefore providing a possible ‘off the shelf’ source of cells for therapeutic use which overcomes the practical limitations of autologous MSCs. Furthermore, MSCs and ESCs have different survival rates and migration patterns in the damaged tendon, suggesting that they may produce different functional effects. This may have clinical relevance to treating tendon injuries in the horse.     

Outcome after lacerations of the superficial and deep digital flexor tendons, suspensory ligament and/or distal sesamoidean ligaments in 106 horses

Objective: To report outcome after the surgical treatment of lacerations of the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), suspensory ligament (SL), and/or distal sesamoidean ligaments (DSL) in horses. Study Design: Case series. Animals: Horses (n=106) with lacerations of the SDFT, DDFT, SL, and/or DSL. Methods: Medical records (1988–2002) were reviewed for signalment, limb and tendon/ligament involvement (location and extent of injury, tendon sheath involvement), method of repair, and outcome. Results: The median age of horses was 7 years and the follow‐up time ranged from 1 to 10 years. Fifty‐five percent of horses returned to their previous level of performance, 27% to a lower level, and 18% were euthanatized. Multivariate statistical analysis demonstrated that the number of structures transected had the most significant influence on outcome. No significant association was detected between outcome and tendon sheath involvement, tendon suturing, casting, or limb affected. Fetlock hyperextension was the most significant complication. Conclusions: A high survival rate can be expected after SDFT, DDFT, SL, and/or DSL lacerations in horses, but only 55% of affected horses returned to their previous activity level. The number of structures affected was the major factor determining whether horses returned to an equal level of performance.     

Are the material properties and matrix composition of equine flexor and extensor tendons determined by their functions?

REASONS FOR PERFORMING STUDY: Injury to the superficial digital flexor tendon (SDFT) is common in competition horses. The SDFT contributes to locomotory efficiency by storing energy; such tendons have low safety margins. Tendons which merely position the limb, including the opposing common digital extensor tendon (CDET), are rarely injured. The current failure of strategies to prevent or effectively treat injury to the SDFT indicates the importance of understanding how it differs from tendons which are not injury-prone. HYPOTHESIS: That the structural and material properties and matrix composition of the SDFT and CDET differ, reflecting their specific functional requirements in vivo. METHODS: Forelimb tendons were harvested from 26 mature horses and loaded to failure prior to matrix composition analysis of specimens. RESULTS: The SDFT had a significantly higher cross-sectional area, structural stiffness, failure load and failure strain and a lower elastic modulus than the CDET (P < 0.0001). CONCLUSIONS: The SDFT has conflicting requirements for strength and elasticity; although as a whole it is a stiffer structure than the CDET, differences in the matrix molecular composition including water and total sulphated glycosaminoglycan contents allow it to remain more elastic as a material. POTENTIAL RELEVANCE: Further information on how the two tendons attain these different properties may be of use in the development of prevention and treatment strategies for SDFT rupture.     

Functional adaptation through changes in regional biochemical characteristics during maturation of equine superficial digital flexor tendons

OBJECTIVE: To quantify and compare biochemical characteristics of the extracellular matrix (ECM) of specimens harvested from tensional and compressive regions of the superficial digital flexor tendon (SDFT) of horses in age classes that include neonates to mature horses. SAMPLE POPULATION: Tendon specimens were collected on postmortem examination from 40 juvenile horses (0, 5, 12, and 36 months old) without macroscopically visible signs of tendonitis. PROCEDURE: Central core specimens of the SDFT were obtained with a 4-mm-diameter biopsy punch from 2 loaded sites, the central part of the mid-metacarpal region and the central part of the mid-sesamoid region. Biochemical characteristics of the collagenous ECM content (ie, collagen, hydroxylysylpyridinoline crosslink, and pentosidine crosslink concentrations and percentage of degraded collagen) and noncollagenous ECM content (percentage of water and glycosaminoglycans, DNA, and hyaluronic acid concentrations) were measured. RESULTS: The biochemical composition of equine SDFT was not homogeneous at birth with respect to DNA, glycosaminoglycans, and pentosidine concentrations. For most biochemical variables, the amounts present at birth were dissimilar to those found in mature horses. Fast and substantial changes in all components of the matrix occurred in the period of growth and development after birth. CONCLUSIONS AND CLINICAL RELEVANCE: Unlike cartilage, tendon tissue is not biochemically blank (ie, homogeneous) at birth. However, a process of functional adaptation occurs during maturation that changes the composition of equine SDFT from birth to maturity. Understanding of the maturation process of the juvenile equine SDFT may be useful in developing exercise programs that minimize tendon injuries later in life that result from overuse.     

Autologous platelet concentrates as a treatment for musculoskeletal lesions in five horses

Two horses with acute tendinopathy of a superficial digital flexor tendon (SDFT) and three horses with chronic proximal desmitis of the suspensory ligament (PDSL) were treated by injecting autologous concentrates of their platelets into the lesions. The lesions were monitored ultrasonographically and clinically. There were significant ultrasonographic and clinical improvements in the two horses with SDFT, but no ultrasonographic improvements in the horses with PDSL; however, they improved clinically and became less lame. All the horses had returned to their pre-injury level of performance by six months after the completion of the treatment, and none of them had suffered a recurrence after 20 months.     

Cell therapy for tendinitis, experimental and clinical report

To compare cultured bone marrow mesenchymal cells (cBMSC), bone marrow mononucleated cells (BMMNCs), and placebo to repair collagenase-induced tissue damage in an equine model of experimental tendonitis, 6 Standardbred horses with no signs of previous SDF tendon injury have been recruited. Three weeks after collagenase treatment an average of either 5.5 x 10(6) cBMSCs or 122.3 x 10(6) BMMNCs, saline solution (placebo) or fibrin glue were injected intralesionally in random order. Horses were stall rested for 21 weeks, and tendon ultrasound scans performed before and during this period. Horses were euthanized and tendons harvested for histology and immunohistochemistry. Data observed in this study showed effectiveness of cBMSC and BMMNC in regenerating tendon tissue after collagenase -induced tendonitis. Both cBMSC and BMMNC transplantation resulted in qualitatively similar regeneration of tendon extracellular matrix in terms of type I/III collagen ratio, fiber orientation, and COMP expression. After this favourable results, 20 horses were recruited referred for spontaneous lesions of the flexor tendons or the suspensory ligament. Horses were treated with autologous graft of BMMNCs.After treatment the. the exercise program allowed was 8 weeks stall rest, 4 weeks hand walking, 4 weeks trotting, 4 weeks of gradually raising of exercise level then horses were gone back to race. US characteristics of lesions started to improve at T3. CSA-l, FPS and TLS were better in all patients, with an appreciable filling of lesions indicated by a decreasing of CSA-l and increasing of TLS. When horses started the exercise program T8 tendon architecture improved, demonstrated by their longitudinal alignment and length. At T6, and persistently in later follow-up, no lameness was evident by clinical examination. At time of writing 12 patients (60%) were go back to races, while other 8 (40%) are under controlled exercise program. Re-injury rate was assessed at 25%. All the owners judged good to excellent the outcome in term of athletic success.