Letrozole-induced inflammatory arthritis and tendinopathy in pediatric rheumatology setting.

Musculoskeletal symptoms associated with the use of aromatase inhibitors are a well-known side effect of these drugs and are more prevalent in postmenopausal women. Aromatase inhibitor-associated symptoms are not overt inflammatory processes so are described as arthralgia syndrome. In contrast, aromatase inhibitor-associated inflammatory conditions such as myopathies, vasculitis, and rheumatoid arthritis were also reported. To our knowledge, inflammatory arthritis or tendinopathy associated with aromatase inhibitors were not reported in children despite their increased off-label use in the pediatric setting. Herein, we report a girl with inflammatory arthritis and tendinopathy associated with letrozole treatment.

A combination of omega-3 and exercise reduces experimental Achilles tendinopathy induced with a type-1 collagenase in rats.

This study aimed to evaluate the effectiveness of omega-3 supplementation with exercise in a collagenase-induced Achilles tendinopathy (AT) rat model. Experimental groups (healthy control (HC), AT, exercise (Ex), omega-3 (W), and Ex+W) were randomly allocated. After a week of adaptation, oral omega-3 was initiated for 8 weeks (5 days/week). The exercise groups performed treadmill running for 30 min/day (5 days/week, 20 m/min, 8 weeks) following one week of adaptation (10 m/min, 15 min/day). Matrix metalloproteinase-13 (MMP-13), interleukin-1 beta (IL-1ß), tumor necrosis factor-alpha (TNF-α), and total antioxidant-oxidant status (TAS) levels were determined in serum samples. Tendon samples were obtained for biomechanical, histopathological, and immunohistochemical assessments. Ultimate tensile force, yield force, stiffness values, collagen type-I alpha 1 expression, and serum TAS significantly decreased (P < 0.05) in AT vs. HC. These values and expression significantly increased in the Ex+W group vs. AT. Serum MMP-13, IL-1ß, and TNF-α levels decreased in all treatment groups vs. AT. The most significant decrease was found in the Ex+W group (P < 0.01). Histopathologically, the improvement in degeneration was statistically significant in the Ex+W group (P < 0.05). Immunohistochemically, MMP-13, IL-1ß, TNF-α, and nitric oxide synthase-2 expression was decreased in all treatment groups vs. AT. In conclusion, omega-3 and exercise might be recommended in AT patients.

A preventable, life-altering case of fluoroquinolone-associated tendonitis.

ABSTRACT: Fluoroquinolones, such as ciprofloxacin and levofloxacin, are broad-spectrum antibacterial agents that have historically been widely used for urinary tract infections, pneumonia, and intra-abdominal infections but are associated with several serious adverse reactions, including tendinopathy and tendon rupture, peripheral neuropathy, and aortic aneurysm. These drugs should not be used for uncomplicated infections unless no other antimicrobial treatment is feasible. This article describes a patient who experienced life-altering disability from a fluoroquinolone, reviews the adverse reactions of this drug class, and discusses recommended treatment for acute uncomplicated cystitis and asymptomatic bacteriuria.

Calcific tendinopathy: an unexpected side effect of tyrosine kinase inhibitor?

Musculoskeletal (MSK) pains have been reported during TKI treatment or after its discontinuation in patients with chronic myeloid leukemia (CML). We hypothesized that MSK pains originate from calcific tendinopathy according to preliminary clinical observations. We conducted a retrospective study including CML patients divided into three groups: patients with MSK pain during TKI treatment; asymptomatic patients during TKI treatment; patients with MSK pain after TKI discontinuation. Patients with MSK pain were clinically evaluated, and the presence of calcific deposits was assessed in X-rays of both shoulders and pelvis. Forty-five patients were included; 14 described MSK pain during TKI treatment and 12 after TKI discontinuation. A diagnosis of rotator cuff tendinopathy was retained for 57.7% of patients and of gluteus tendinopathy in 19.2%. The prevalence of calcifications in shoulders and/or hips was 64.3% in symptomatic patients receiving TKIs, 63.2% in asymptomatic patients and 75.0% in patients with MSK pain after TKI treatment.

Friedelin Alleviates the Pathogenesis of Collagenase-Induced Tendinopathy in Mice by Promoting the Selective Autophagic Degradation of p65.

With the development of an aging population, tendinopathy has become a common musculoskeletal disease in the elderly with a high recurrence rate and no curative treatment. The inflammation mediated by NF-κB signaling plays an important role in tendon senescence and degeneration. Friedelin (FR) is a triterpenoid derived from green plants, which has a variety of pharmacological functions, such as analgesia, anti-inflammation, antioxidation, and anti-tumor functions. However, the role and mechanism of FR in tendinopathy are unclear. Here, we found that FR improved the mechanical strength of the Achilles tendon, restored the orderly arrangement of collagen fibers, reduced inflammatory cell infiltration, and promoted tenogenesis, thereby blocking the progression of tendinopathy. Mechanistically, FR promoted the autophagic degradation of p65 by enhancing the interaction between p62 and p65 and effectively inhibited the activation of the NF-κB pathway, thus alleviating the inflammatory response of tenocytes. In addition, FR recruited E3 ubiquitin enzyme RNF182 to increase the K48-linked ubiquitination of p65 and promoted p62-mediated autophagic degradation. Furthermore, blocking ubiquitination reversed the degradation of p65 by FR. Therefore, these findings identify the new pharmacological mechanism of the anti-inflammatory effect of FR and provide a new candidate drug for the treatment of tendinopathy.

[Achilles tendinopathy in a hemodialysis patient complicated by rupture of the Achilles tendon due to self-medication with ciprofloxacin: about a case]. / Tendinopathie achilléenne compliquée d´une rupture du tendon d´Achille consécutives à une automédication par la ciprofloxacine chez une hémodialysée: à propos d´un cas.

This study aims to remind clinicians of fluoroquinolone-related tendinopathies. They are rare side effects, but which can result in functional disability. We report the case of a 79-year-old woman with a 11-year history of haemodialysis who had sudden left ankle pain and functional impairment in the ipsilateral member on day 5th after self-medication with ciprofloxacin. Comorbidities included chronic gonarthrosis, secondary hyperparathyroidism and ischemic heart disease. The diagnosis of bilateral Achilles tendinopathy and rupture of the left Achilles tendon was retained due to clinical features and confirmed by ultrasound of ankles. Ciprofloxacin-associated tendon rupture was evaluated using the French method of accountability for drug unexpected side effects or toxicity. Tendon rupture management was based on surgery followed by functional rehabilitation program with satisfactory outcome. The frequency of fluoroquinolone-related tendinopathies ranges from 15 to 20 accidents per 100,000 subjects treated, a third of whom are complicated by tendon rupture. Incidence is related to age, affecting mainly people > 60 years and involving tissular aging. Pefloxacin and ciprofloxacin are the most offending molecules. In our study, the delay in the onset of symptoms on day 5 after self-medication was consistent with literature. We detected some common contributing factors including chronic renal failure, hemodialysis and the assumption of statins and corticosteroids. Fluoroquinolone-related tendinopathies are characterized by common clinical features which allow diagnosis. They mostly affect Achilles tendon. They are bilateral in 40-66% of cases. Tendon rupture is the main complication. Management is based on surgery. It allows to restore anatomy and to prevent detrimental functional disability. We here report a rare but potentially serious fluoroquinolones-related side effect, exposing the patient to the risk of functional disability. Advanced age, chronic renal failure, chronic haemodialysis, concomitant use of statins and corticosteroids are common contributing factors confirmed in this study. Hemodialysis patients constitute a population at risk; hence the importance of remote monitoring after treatment with these molecules.

Influence of Radial Pressure Wave Therapy (RPWT) on collagenase-induced Achilles tendinopathy treated with Platelet Rich Plasma and Autologous Adipose Derived Stem Cells.

Tendinopathy treatment poses a current challenge for sport medicine due to unique physiology and biomechanics of tendons. The goal of this work was to compare the efficacy of the addition of the radial pressure wave therapy (RPWT) treatment to injection of autologous Adipose Derived Stem Cells (ADSCs) or Platelet Rich Plasma (PRP) in the therapeutic procedure for collagenase induced Achilles tendinopathy in sheep. 14 sheep (aged 5 and 6 years, Polish Mountain Sheep breed, weight 60-70 kg) were injected bacterial collagenase type 1A-S (Clostridium histolyticum, C-5894, Sigma Aldrich, Poznan, Poland) bilaterally to Achilles tendons. Subsequently, the animals were injected with PRP (7 sheep) or ADSCs (7 sheep) to previously induced tendinopathy foci. Left limbs of all the animals were additionally treated with RPWT focused above the tendinopathy origins. Treatment progress was controlled by ultrasound scans, and tendon samples were taken on the 126th day of the experiment. Tendon samples taken from the sheep treated with RPWT+ADSCs showed lower cellularity and the highest number of thick collage fibers. Samples taken from the sheep treated with RPWT+PRP showed an elevated rate of neovascularization. Addition of the RPWT to ADSCs injections in the treatment of induced Achilles tendinopathy in sheep resulted in good quality of the tissue regeneration. Dual therapy with RPWT+PRP injection can lead to neovascularization in the tendon tissue.

Systemic inflammatory response to the Radial Pressure Wave Therapy (RPWT) in collagenase-induced Achilles tendinopathy treated with Adipose Derived Stem Cells or Platelet Rich Plasma.

Novel tendinopathy treatment protocols should be assessed for safety. The goal of this work was to compare differences in selected systemic inflammatory marker concentrations after two treatment protocols for collagenase induced Achilles tendinopathy in sheep. 14 sheep (aged 5 and 6 years, Polish Mountain Sheep breed, weight 60-70kg) were injected with bacterial collagenase type 1A-S (Clostridium histolyticum, C-5894, Sigma Aldrich, Poznan, Poland) bilaterally to Achilles tendons. Subsequently, the animals were injected with Platelet Rich Plasma (7 sheep) or Adipose Derived Stem Cells (7 sheep) to induced tendinopathy foci. Left limbs of all sheep were additionally treated with Radial Pressure Wave Therapy (RPWT) focused above the tendinopathy origins. Treatment progress was controlled by ultrasound scans, and tendon samples were taken on the 126th day of the experiment. Serum Amyloid A (SAA) concentration showed mild elevation before the experiment (2 sheep from group I, 4 sheep from group II) and two days after the intratendinous growth factors injection ( 4 sheep from group I, 3 sheep from group II) combined with RPWT (mean 22,63 mg/L and 53, 6 mg/L respectively). Haptoglobine (Hp) concentration increased from 0 to 0,01 g/L in 2 animals from group I two days after injection. These values declined to 0 during the course of the treatment. Fibrinogen (Fb) concentrations were within reference levels throughout the research, although mild elevation was observed before the treatment course in 6 sheep from group I and 1 sheep from group II. In conclusion, addition of RPWT to growth factors injections in the treatment of yatrogenic Achilles tendinopathy in sheep did not induce systemic inflammatory response.

Can alternate-day Statin regimen minimize its adverse effects on muscle and tendon? A systematic review.

OBJECTIVE: To review evidence-based data with respect to safety and efficacy of alternate-day statin therapy in dyslipidaemia compared to the standard daily dose. METHODS: The literature review was conducted at Aga Khan University Hospital, Karachi from July, 2016 to August, 2017. Electronic database search was carried out to compile available literature using PubMed, Excerpta Medica database and Google Scholar. The most relevant evidence-based research articles published over 10 years were selected. The latest search was dated August 03, 2017. RESULTS: A total of 2,074 articles were initially located. Alternate day statin regimen was reported in 53% of articles. Adverse effects on muscle and tendon were reported in 69% of articles. After scrutiny, 19(0.9%) studies covering alternate-day statin-mediated muscle and tendon disorders and 9(0.4%) studies encompassing the potential pathophysiological mechanisms of statin-associated muscle and tendon injury were selected. Except pravastatin and lovastatin, alternate-day statin therapy was almost as effective in lowering total cholesterol, low-density lipoprotein cholesterol and triglycerides as the daily dosing with low incidence of muscle toxicity and tends in opathy. CONCLUSIONS: Alternate-day statin regimen was found to be very well tolerated and might be an effective and safe remedy in clinical practice.

Percutaneous soft tissue release performed using a blunt cannula in rabbits with chronic collagenase-induced Achilles tendinopathy.

BACKGROUND: This study investigated the effects of percutaneous soft tissue release (PSTR) performed using a blunt cannula on (1) the inflammatory cells-count, (2) expressions of calcitonin gene-related peptide (CGRP) and (3) substance P (SP) in rabbits with chronic phase of collagenase-induced Achilles tendinopathy. METHODS: Thirty-two adult male New Zealand rabbits were randomly divided into four groups: (1) collagenase and PSTR treatment; (2) collagenase and sham-operated PSTR treatment; (3) vehicle-only injection and PSTR treatment; and (4) vehicle-only injection and sham-operated PSTR treatment. Achilles tendon of adult male rabbits was injected with 10µl of collagenase under ultrasonography localization. After 30 days, PSTR was performed using an 18G beauty cosmetic blunt tip micro cannula needle to release the soft tissue and paratenon above the inflamed Achilles tendon. The treated tendons and spinal cords of L5-S2 were harvested 5days after treatment for histological assessment and immunohistochemical analysis. RESULTS: Histopathological examination revealed that PSTR achieved significant reduction in hypercellularity with pronounced infiltration of immune cells at the site of paratenon in tendons injected with collagenase compared with sham operation (p<0.05). Immunohistochemical analysis also showed marked decrease in expression of CGRP in tendon and SP in dorsal horns after PSTR (p<0.05). CONCLUSIONS: This study showed positive effects in an animal model of chronic tendinopathy, and can be considered a treatment option, but that further research is necessary to determine its role in clinical practice.

Isotretinoin induced achilles tendinopathy: Histopathological and biomechanical evaluation on rats.

OBJECTIVE: The aim of the present study was to evaluate histopathological and biomechanical effects of isotretinoin on Achilles tendon. MATERIALS & METHODS: Sixteen rats were divided into two groups including the control group (n = 8) and isotretinoin group (n = 8). The control group received 1.42 ml/kg soy oil per day whereas the isotretinoin group received 15 mg/kg/day (gavage dose 1.42 ml/kg) isotretinoin dissolved in soy oil through gavage method for 6 weeks. Achilles tendons were excised at the end of week 6. The tendon samples were evaluated by hematoxylin-eosin under a light microscope. Quantitative evaluation was performed via Movin and Bonar scoring. A computer-monitored tensile testing machine was utilised for biomechanical testing. Biomechanical characteristics of the tendon samples (elastic modulus, yield force, ultimate tensile force) were measured. RESULTS: Histopathological evaluation revealed a significantly higher Movin and Bonar scores in histopathological evaluation. Movin score in isotretinoin group was 4.1 ± 2.5 and it was 2.3 ± 1.0 in control group (p = 0.032). Bonar score in isotretinoin group was 2.9 ± 1.4 and it was 1.6 ± 0.7 in control group (p = 0.022). In line with histopathological evaluation, biomechanical measurements in isotretinoin group (elastic modulus, yield force, ultimate tensile force) were significantly lower than the control group. Elastic modulus in isotretinoin group was 227 ± 27.7 N/mm2 and in control group it was 281.7 ± 38.7 N/mm2 (p = 0.006). In isotretinoin group; yield force was 33.7 ± 4.3 Pa and in control group it was 40.8 ± 5.9 Pa (p = 0.021). Ultimate tensile force in isotretinoin group was 35.7 ± 4.2 Pa and in control group it was 44 ± 7 Pa (p = 0.009). CONCLUSION: The present study detected histopathological and biomechanical negative effect of isotretinoin on Achilles tendon. Therefore, isotretinoin should be questioned in medical history of patients with tendinopathy.

Tendonitis and Tendon Rupture After Treatment With Rituximab: A Case Series.

CLINICAL DATA: Rituximab is a mouse/human chimeric anti-CD20 IgG1 monoclonal antibody used to treat cancer and autoimmune conditions. Side effects of rituximab include fever, rash, cytopenia and hypotension, back pain, arthralgia, and myalgia. Here, we report on 3 patients who developed moderate to severe tendonitis after the second infusion of rituximab. THERAPEUTIC CHALLENGE: We report 3 patients who developed tendonitis after the second infusion of rituximab. These patients were undergoing treatment for connective tissue diseases. All 3 patients received 2 rituximab infusions, 2 weeks apart. The 3 cases developed clinical tendonitis that was confirmed by magnetic resonance imaging in 2 cases. INTERPRETATION: This is the first case series reporting new onset tendonitis in patients with connective tissue diseases after rituximab therapy. All 3 cases developed tendonitis 1 week after receiving the second dose of rituximab. Clinical features of tendonitis resolved 3-4 months in all cases. The underlying pathogenic mechanism by which rituximab causes tendonitis is not clear, but tendonitis and tendon rupture have been reported after using other medications such as quinolones. The tendon damage was progressive leading to tendon rupture in 1 patient, highlighting the importance of early recognition. It is plausible that there is a cause-effect relation between tendonitis and administration of rituximab in our 3 cases, since none of these cases had previous history of tendonitis; however, more data are needed to confirm this observation.

Statin-induced calcific Achilles tendinopathy in rats: comparison of biomechanical and histopathological effects of simvastatin, atorvastatin and rosuvastatin.

PURPOSE: Accumulating clinical evidence indicates the risk of tendinopathy and spontaneous and/or simultaneous tendon ruptures associated with statin use. This experimental study was designed to evaluate and compare the biomechanical and histopathological effects of the three most commonly prescribed statins (simvastatin, atorvastatin and rosuvastatin) on the Achilles tendon in rats. METHODS: Statins were administered by gavage to rats at daily doses of 20 and 40 mg/kg for 3 weeks. One week later, the Achilles tendons were dissected and their biomechanical properties, including ultimate tensile force, yield force and elastic modulus, were determined. The samples were stained with haematoxylin-eosin and examined under a light microscope. The biomechanical properties of the tibia were tested by three-point bending test. Bone mineral density (BMD) and the lengths of tibias were measured by computed tomography. RESULTS: All the statins caused deterioration of the biomechanical parameters of the Achilles tendon. Histopathological analysis demonstrated foci of dystrophic calcification only in the statin-treated groups. However, the number and the total area of calcific deposits were similar between the statin groups. The biomechanical parameters of tibias were improved in all the statin groups. BMD in the statin-treated groups was not significantly different from the control group. CONCLUSION: All the statins tested are associated with calcific tendinopathy risk of which full awareness is required during everyday medical practice. However, statin-associated improvement of bone biomechanical properties is a favourable feature which may add to their beneficial effects in atherosclerotic cardiovascular disease, especially in the elderly.

Fluoroquinolone-Associated Tendinopathy: Does Levofloxacin Pose the Greatest Risk?

Fluoroquinolone antibiotics recently have gained increased national attention due to safety concerns. A well-described and serious adverse event associated with receipt of fluoroquinolones is tendinitis and tendon rupture. These tendon injuries can result in long-term sequelae, including chronic pain and mobility restrictions, and may warrant surgery. Due to the severity of these adverse events, a black box warning is included in the product labeling of all fluoroquinolones. In light of the mounting concerns surrounding fluoroquinolone-associated toxicities, the purpose of this clinical review is to provide a comprehensive summary of the risk of tendinopathy associated with levofloxacin, one of the most widely prescribed antibiotics in the United States, across in vitro, animal, and clinical studies, relative to other antibiotics. As part of this review, clinical presentation and onset, proposed mechanisms, patient-specific risk factors, and management of fluoroquinolone-induced tendon injury are summarized. Data were obtained from a comprehensive PubMed literature search and a review of U.S. Food and Drug Administration documents. Although tendinopathy is considered a fluoroquinolone class-wide toxicity, data from in vitro studies, animal studies, patient-level analyses, and large national and international surveillance reports suggest that levofloxacin, as well as its parent compound ofloxacin, possess higher propensities to cause tendon damage relative to other fluoroquinolones. Risk with ofloxacin and levofloxacin appears to be exposure dependent, with higher doses and longer durations being most commonly associated with tendinopathy. Other well-described patient risk factors for fluoroquinolone-associated tendinopathy include older age (older than 60 yrs), receipt of concomitant corticosteroid therapy, presence of renal dysfunction, and history of solid organ transplantation. Given widespread use of levofloxacin across patient care settings, knowledge of both patient- and drug-specific characteristics associated with increased risk of tendinitis and tendon rupture can promote safe use of levofloxacin and other fluoroquinolones.

Adipose-Derived Stem Cells Improve Collagenase-Induced Tendinopathy in a Rat Model.

BACKGROUND: Tendinopathy is a common and highly prevalent musculoskeletal disorder characterized by repetitive activity-related pain and focal tendon tenderness. Histopathologically, tendinopathic tissue mainly shows degenerative changes. Therefore, tendinopathy is not affected by anti-inflammatory therapies. A novel approach, including a stem cell-based therapy, may be beneficial for its treatment. PURPOSE/HYPOTHESIS: The purpose of this study was to evaluate the effects of adipose-derived stem cells (ASCs) on tendon healing in a rat tendinopathy model. The hypothesis was that ASC transplantation would improve degeneration in collagenase-induced tendinopathy. STUDY DESIGN: Controlled laboratory study. METHODS: Sixteen F344/NSlc rats underwent collagenase injection into the Achilles tendon to induce tendinopathy. At 1 week after collagenase injection, 8 rats received ASCs (ASC group) and 8 received phosphate-buffered saline alone (PBS group). Animals were sacrificed at 4 or 12 weeks after ASC administration, and the degree of degeneration in each tendon was histologically evaluated according to the Bonar scale. The microstructure of healing tendons was observed by scanning electron microscopy. Reverse-transcription polymerase chain reaction (RT-PCR) was performed to measure the ratio of type III collagen messenger RNA (mRNA) to type I collagen mRNA in tendons. RESULTS: The median Bonar scale score in the ASC and PBS groups was 2.5 and 5.33 at 4 weeks after treatment and 1.0 and 4.0 at 12 weeks after treatment, respectively. Histologically, the ASC group showed a significantly lower degree of tendon degeneration than the PBS group at both time points. In the RT-PCR analysis, the ratio of type III collagen to type I collagen was significantly lower in the ASC group than in the PBS group at 12 weeks after treatment. Moreover, this ratio decreased over time in the ASC group, whereas it increased over time in the PBS group. CONCLUSION: The study findings demonstrate that the application of ASCs results in significant improvement in the pathological findings associated with tendinopathy and the normalization of collagen ratios within the affected tendon. CLINICAL RELEVANCE: Subcutaneous adipose tissue can be harvested easily, and ASC administration might have the potential to rapidly treat tendinopathy.

Tendon-derived progenitor cells improve healing of collagenase-induced flexor tendinitis.

Tendinitis is a common and a performance-limiting injury in athletes. This study describes the value of intralesional tendon-derived progenitor cell (TDPC) injections in equine flexor tendinitis. Collagenase-induced tendinitis was created in both front superficial digital flexor (SDF) tendons. Four weeks later, the forelimb tendon lesions were treated with 1 × 107 autogenous TDPCs or saline. Tendinitis was also induced by collagenase in one hind SDF tendon, to study the survival and distribution of DiI-labeled TDPCs 1, 2, 4, and 6 weeks after injection. The remaining normal tendon was used as a "control." Twelve weeks after forelimb TDPC injections, tendons were harvested for assessment of matrix gene expression, biochemical, biomechanical, and histological characteristics. DiI-labeled TDPCs were abundant 1 week after injection but gradually declined over time and were undetectable after 6 weeks. Twelve weeks after TDPC injection, collagens I and III, COMP and tenomodulin mRNA levels were similar (p = 0.3) in both TDPC and saline groups and higher (p < 0.05) than normal tendon. Yield and maximal stresses of the TDPC group were significantly greater (p = 0.005) than the saline group's and similar (p = 0.6) to normal tendon. However, the elastic modulus of the TDPC and saline groups were not significantly different (p = 0.32). Histological assessment of the repair tissues with Fourier transform-second harmonic generation imaging demonstrated that collagen alignment was significantly better (p = 0.02) in TDPC group than in the saline controls. In summary, treating collagenase-induced flexor tendon lesions with TDPCs improved the tensile strength and collagen fiber alignment of the repair tissue. Study Design © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2162-2171, 2016.

A Case-Based Approach to Evaluate the Potential Risks Associated with Fluoroquinolones and Steroids.

Fluoroquinolones (FQs) are a frequently prescribed class of antibacterial agents. FQs are widely used but may carry serious side effects particularly pronounced in older adults, and the Food and Drug Administration recently suggested FQs should not be routinely used in certain conditions if alternative options are available. Research has demonstrated that the risk of tendinitis and tendon rupture associated with FQs is one of the highest in older adults who are concurrently treated with steroids. Health care providers and pharmacists involved in the treatment of older adults should be aware of this potential drug interaction, which may lead to serious side effects and safety concerns.

Fluoroquinolone-mediated Achilles rupture: a case report and review of the literature.

Fluoroquinolone use for the treatment of bacterial infections is a common practice for foot and ankle surgeons because of its rather broad-spectrum coverage against common pathogens, good tissue penetration, and high bioavailability. An associated risk of tendinopathy has been reported in published studies, although tendon rupture has been much less frequent. In addition, tendinopathy has been more commonly reported with earlier generations of fluoroquinolones. We present a case of levofloxacin-mediated Achilles rupture that was complicated by the presence of an infected hematoma and abscess and subsequent long-term postoperative follow-up data, with a review of the literature.

The low level laser therapy (LLLT) operating in 660 nm reduce gene expression of inflammatory mediators in the experimental model of collagenase-induced rat tendinitis.

Tendinopathy is a common disease with a variety of treatments and therapies. Laser therapy appears as an alternative treatment. Here, we investigate the effects of laser irradiation in an experimental model of tendinitis induced by collagenase injection on rats' Achilles tendon, verifying its action in important inflammatory markers. Male Wistar rats were used and divided into five groups: control saline (C), non-treated tendinitis (NT) and tendinitis treated with sodium diclofenac (D) or laser (1 J) and (3 J). The tendinitis was induced by collagenase (100 µg/tendon) on the Achilles tendon, which was removed for further analyses. The gene expression for COX-2; TNF-α; IL-6; and IL-10 (RT-PCR) was measured. The laser irradiation (660 nm, 100 mW, 3 J) used in the treatment of the tendinitis induced by collagenase in Achilles tendon in rats was effective in the reduction of important pro-inflammatory markers such as IL-6 and TNF-α, becoming a promising tool for the treatment of tendon diseases.

Avaliação da migração das células progenitoras após terapia da tendinite equina / Migration evaluation of progenitor cells after treatment of equine tendinitis

A terapia celular vem sendo utilizada com resultados promissores no tratamento da tendinite equina, entretanto ainda existem dúvidas quanto à persistência e ao comportamento dessas células quando implantadas no local da lesão, e quanto à sua migração para outros focos inflamatórios. O objetivo deste estudo foi avaliar a marcação das células-tronco mesenquimais (CTMs) com nanocristal antes e após o implante em lesões tendíneas experimentais do tendão flexor digital superficial (TFDS) de equinos, bem como observar a possibilidade de migração das CTMs marcadas para outro foco de lesão, o membro contralateral do mesmo animal. Para isso, foi realizada a indução de lesão experimental no TFDS em ambos os membros torácicos de cinco equinos e, após sete dias, foram implantadas as CTMs autólogas marcadas com o nanocristal Qtracker 655 em um dos membros dos animais. Após sete dias do implante, foi realizada a biópsia tendínea para posterior avaliação histopatológica, utilizando-se microscopia com fluorescência. Também foi realizado o teste de viabilidade celular antes e após a incubação com o nanocristal. As CTMs marcadas e injetadas no tecido tendíneo mantiveram sua fluorescência sete dias após seu implante, e não ocorreu migração para o membro contralateral. O uso do nanocristal para a marcação das CTMs derivadas da medula óssea equina mostrou-se efetivo pelo fato de essa nanopartícula não ter alterado a viabilidade celular e por ela ter permanecido ativa durante o período implantado...

Cell therapy has been used with promising results in the treatment of equine tendinitis. However, there are still doubts about the persistence and behavior of these cells implanted in the injured tissue and their migration to other inflamed sites. The aim of this study was to evaluate the labeling of mesenchymal stem cells (MSCs) with nanocrystals before and after implantation in experimental tendinitis of the superficial digital flexor tendon (SDFT) of horses, observing the migration possibility of MSCs marked to another lesion, performed on the contralateral limb of the same animal. An experimental lesion was induced in SDFT in both forelimbs of five horses, and after seven days autologous MSCs labeled with Qtracker(r) 655 were implanted in one member of the animals. Tendon biopsy was performed for subsequent histopathological evaluation using fluorescence microscopy seven days after the implant. Cell viability test was also performed before and after incubation with the cell labeling kit. MSCs labeled and injected into the tendon tissue maintained their fluorescence seven days after their implantation and there was no migration to the contralateral limb. The use of nanocrystals for labeling MSCs was effective because it does not alter cell viability and remains active during the experimental period...