Fluoroquinolones cause changes in extracellular matrix, signalling proteins, metalloproteinases and caspase-3 in cultured human tendon cells

Achilles tendon ruptures related to fluoroquinolone use - How can we manage these patients? A case series

BACKGROUND

Fluoroquinolone antibiotics can increase the risk of tendon rupture. Treatment of these Achilles ruptures can be difficult due to comorbidities.

METHODS

A case series of 13 consecutive patients with Achilles ruptures following fluoroquinolone use were identified over a 2 year period through the Achilles Tendon rupture clinic and managed conservatively using functional rehabilitation. Follow-up with the Achilles tendon rupture score (ATRS) was completed at 3 months, 6 months and 12 months.

RESULTS

Improvements were seen in ATRS scores over 12 months.

CONCLUSIONS

This case series is the largest published. Improvements were seen in ATRS scores indicating that this cohort can be managed successfully using functional rehabilitation after fluoroquinolone-induced Achilles rupture.

Fluoroquinolones and the risk of aortic aneurysm or aortic dissection: an updated systematic review and meta-analysis including 53,651,283 patients

INTRODUCTION

The association between fluoroquinolone use and the risk of aortic aneurysm as well as the risk of aortic dissections remains uncertain, primarily due to conflicting findings from observational studies. We sought to conduct a double-systematic review and meta-analysis of all observational studies to assess the existence and extent of both these associations. The aim of our study is to assess the role of Fluoroquinolone on aortic aneurysm and aortic dissection in comparison to other antibiotics.

EVIDENCE ACQUISITION

MEDLINE and Cochrane CENTRAL were systematically searched up till June 2021 for observational studies studying the correlation between fluoroquinolone usage and aortic aneurysms and dissections. Random-effects pooling was used to calculate adjusted hazard ratios (HRs) with 95% confidence intervals (CI). To assess publication bias, propensity score matching was conducted, and heterogeneity was evaluated by using I2 statistics.

EVIDENCE SYNTHESIS

Of 688 potentially relevant articles, 635 titles were screened. Ten studies were included in the systematic review, and 4 observational studies with 53,651,283 participants were eligible to be included in the meta-analysis. Pooled estimates showed that fluoroquinolone use was associated with a higher risk of aortic aneurysm when compared to other Antibiotics (HR 1.84, 95% CI 1.10-2.48; P<0.00001). However, fluoroquinolones had no significant effect on the risk of developing aortic dissection (HR 1.09, 95% CI 0.96-1.25; P=0.19).

CONCLUSIONS

The present analysis suggests that fluoroquinolone usage is more strongly linked to aortic aneurysm than other antibiotics. However, there was no statistically significant link between fluoroquinolone and aortic dissection. As a result, clinicians should exercise caution when administering fluoroquinolone to patients who have a history of or are at risk of aortic disease.

The Research Status, Potential Hazards and Toxicological Mechanisms of Fluoroquinolone Antibiotics in the Environment

Fluoroquinolone antibiotics are widely used in human and veterinary medicine and are ubiquitous in the environment worldwide. This paper recapitulates the occurrence, fate, and ecotoxicity of fluoroquinolone antibiotics in various environmental media. The toxicity effect is reviewed based on in vitro and in vivo experiments referring to many organisms, such as microorganisms, cells, higher plants, and land and aquatic animals. Furthermore, a comparison of the various toxicology mechanisms of fluoroquinolone antibiotic residues on environmental organisms is made. This study identifies gaps in the investigation of the toxic effects of fluoroquinolone antibiotics and mixtures of multiple fluoroquinolone antibiotics on target and nontarget organisms. The study of the process of natural transformation toward drug-resistant bacteria is also recognized as a knowledge gap. This review also details the combined toxicity effect of fluoroquinolone antibiotics and other chemicals on organisms and the adsorption capacity in various environmental matrices, and the scarcity of data on the ecological toxicology evaluation system of fluoroquinolone antibiotics is identified. The present study entails a critical review of the literature providing guidelines for the government to control the discharge of pollutants into the environment and formulate policy coordination. Future study work should focus on developing a standardized research methodology for fluoroquinolone antibiotics to guide enterprises in the design and production of drugs with high environmental biocompatibility.

Is Fluoroquinolone Exposure after Primary Tendon Repair Associated with Higher Rates of Reoperations? A Matched Cohort Study

Background

The association between tendon damage and fluoroquinolone (FQ) antibiotics has been well documented. However, there is limited data evaluating the impact of postoperative FQ use on outcomes of primary tendon repairs. The purpose of this study was to compare rates of reoperation for patients with FQ exposure after primary tendon repair versus controls.

Methods

A retrospective cohort study was conducted using the PearlDiver database. All patients who underwent primary repair of distal biceps ruptures, Achilles tendon ruptures, and rotator cuff tears were identified. For each tendon, patients who were prescribed FQs within 90 days postoperatively were propensity score matched at a 1:3 ratio with controls without postoperative FQ prescriptions across age, sex, and several comorbidities. Rates of reoperation were compared at two years postoperatively with multivariable logistic regression.

Results

A total of 124,322 patients who underwent primary tendon procedures were identified, including 3,982 (3.2%) patients with FQ prescriptions within 90 days postoperatively: 448 with distal biceps repair, 2,538 with rotator cuff repair, and 996 with Achilles tendon repair. These cohorts were matched with 1,344, 7,614, and 2,988 controls, respectively. Patients with postoperative FQ prescriptions exhibited significantly higher rates of revision surgery after primary repair of distal biceps ruptures (3.6% vs. 1.7%; OR 2.13; 95% CI, 1.09-4.04), rotator cuff tears (7.1% vs. 4.1%; OR 1.77; 95% CI, 1.48-2.15), and Achilles tendon ruptures (3.8% vs. 1.8%; OR 2.15; 95% CI, 1.40-3.27).

Conclusion

Patients with FQ prescriptions within 90 days after primary tendon repair demonstrated significantly higher rates of reoperations for distal biceps, rotator cuff, and Achilles tendon repair at two years postoperatively. To achieve optimal outcomes and avoid complications in patients following primary tendon repair procedures, physicians should consider prescribing alternative non-FQ antibiotics and counsel patients on the risk of reoperation associated with postoperative FQ use.

Short-Term Exposure to Ciprofloxacin Reduces Proteoglycan Loss in Tendon Explants

Fluoroquinolone antibiotics are associated with increased risk of tendinopathy and tendon rupture, which can occur well after cessation of treatment. We have previously reported that the fluoroquinolone ciprofloxacin (CPX) reduced proteoglycan synthesis in equine tendon explants. This study aimed to determine the effects of CPX on proteoglycan catabolism and whether any observed effects are reversible. Equine superficial digital flexor tendon explant cultures were treated for 4 days with 1, 10, 100 or 300 µg/mL CPX followed by 8 days without CPX. The loss of [³⁵S]-labelled proteoglycans and chemical pool of aggrecan and versican was studied as well as the gene expression levels of matrix-degrading enzymes responsible for proteoglycan catabolism. CPX suppressed [³⁵S]-labelled proteoglycan and total aggrecan loss from the explants, although not in a dose-dependent manner, which coincided with downregulation of mRNA expression of MMP-9, -13, ADAMTS-4, -5. The suppressed loss of proteoglycans was reversed upon removal of the fluoroquinolone with concurrent recovery of MMP and ADAMTS mRNA expression, and downregulated TIMP-2 and upregulated TIMP-1 expression. No changes in MMP-3 expression by CPX was observed at any stage. These findings suggest that CPX suppresses proteoglycan catabolism in tendon, and this is partially attributable to downregulation of matrix-degrading enzymes.

Antibiotic Therapy and Athletes: Is the Mitochondrial Dysfunction the Real Achilles’ Heel?

It is widely recognized that athletes consume oral antibiotics almost twice as often as observed in the non-sports population in order to reduce as much as possible the period of inactivity due to bacterial diseases. However, increasing evidences have demonstrated the ability of some classes of antibiotics to induce muscle weakness, pain, and a feeling of fatigue upon resuming physical activity conditions that considerably limit the athletic performance of athletes, ascribable to alterations in the biochemical mechanisms underlying normal musculoskeletal activity, such as mitochondrial respiration. For this reason, tailoring a treatment plan for effective antibiotics that limit an athlete’s risk is paramount to their safety and ability to maintain adequate athletic performance. The present review illustrates and critically analyzes the evidence on the use of antibiotics in sports, deepening the molecular mechanisms underlying the onset and development of muscle–tendon alterations in athletes as well as delineating the pharmacological strategies aimed at counteracting such adverse events.

Do fluoroquinolones increase aortic aneurysm or dissection incidence and mortality? A systematic review and meta-analysis

Objective

The aim of this study was to determine the association between fluoroquinolones (FQs) use, the risk of de novo aortic aneurysm or dissection (AAD), and the prognosis of patients with pre-existing AAD.

Materials and methods

We searched PubMed, EMBASE, CENTRAL, Scopus, and Web of Science on 31 March 2022. Observational studies that evaluated the association of FQs with AAD risk in the general population or FQs with the prognosis of patients with preexisting AAD and presented adjusted effect estimates were included. Two reviewers assessed study eligibility, extracted data, and assessed the risk of bias and certainty of evidence using GRADE.

Results

Of the 13 included studies, 11 focused on the association of FQs with de novo AAD incidence, and only one study investigated the association of FQs with the patient with AAD prognosis. FQ use was associated with an increased risk of de novo AAD within 30 days (RR: 1.42; 95% CI: 1.11-1.81; very low certainty) and 60 days (RR: 1.44; 95% CI: 1.26-1.64; low certainty). Specifically, the association was significant when compared with amoxicillin, azithromycin, doxycycline, or no antibiotic use. Furthermore, patients with preexisting AAD exposure to FQ had an increased risk of all-cause mortality (RR: 1.61; 95% CI: 1.50-1.73; moderate certainty) and aortic-specific mortality (RR: 1.80; 95% CI: 1.50-2.15; moderate certainty), compared to the non-exposed FQ group within a 60-day risk period.

Conclusion

FQs were associated with an increased incidence of AAD in the general population and a higher risk of adverse outcomes in patients with preexisting AAD. Nevertheless, the results may be affected by unmeasured confounding factors. This should be considered by physicians contemplating using FQs in patients with aortic dilation and those at high risk of AAD.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42021230171].

Ciprofloxacin reduces tenocyte viability and proteoglycan synthesis in short-term explant cultures of equine tendon

Fluoroquinolones are an effective, broad-spectrum antibiotic used to treat an array of bacterial infections. However, they are associated with an increased risk of tendinopathy and tendon rupture even after discontinuation of treatment. This condition is known as fluoroquinolone-associated tendinopathy, the underlying mechanisms of which are poorly understood. While many factors may be involved in the pathophysiology of tendinopathies in general, changes in tenocyte metabolism and viability, as well as alteration of proteoglycan metabolism are prominent findings in the scientific literature. This study investigated the effects of ciprofloxacin, a common fluoroquinolone, on cell viability, proteoglycan synthesis, and proteoglycan mRNA expression in equine superficial digital flexor tendon explants after 96 h treatment with between 1–300 µg/mL ciprofloxacin, and again after 8 days discontinuation of treatment. Ciprofloxacin caused significant reductions in cell viability by between 25–33% at all dosages except 10 µg/mL, and viability decreased further after 8 days discontinuation of treatment. Proteoglycan synthesis significantly decreased by approximately 50% in explants treated with 100 µg/mL and 300 µg/mL, however this effect reversed after 8 days in the absence of treatment. No significant mRNA expression changes were observed after the treatment period with the exception of versican which was down-regulated at the highest concentration of ciprofloxacin. After the recovery period, aggrecan, biglycan and versican genes were all significantly downregulated in explants initially treated with 1–100 µg/mL. Results from this study corroborate previously reported findings of reduced cell viability and proteoglycan synthesis in a whole tissue explant model and provide further insight into the mechanisms underlying fluoroquinolone-associated tendinopathy and rupture. This study further demonstrates that certain ciprofloxacin induced cellular changes are not rapidly reversed upon cessation of treatment which is a novel finding in the literature.

[Safety in the selection of oral antibiotic treatment in community infections, beyond COVID-19]

Los antibióticos orales son uno de los fármacos más utilizados en la comunidad. Sus efectos adversos son generalmente poco frecuentes y leves, e incluyen toxicidad e interacciones medicamentosas. El mecanismo de producción es variado y no siempre bien conocido. El conocimiento de los efectos adversos con relevancia clínica puede permitir hacer un uso más juicioso de los antibióticos basados en el principio primero no hacer daño, primun non nocere. En esta revisión exploramos los principales efectos adversos de los antibióticos orales con énfasis en los β-lactámicos, macrólidos y fluoroquinolonas.

The incidence of collagen-associated adverse events in pediatric population with the use of fluoroquinolones: a nationwide cohort study in Taiwan

BACKGROUND

To evaluate the safety of using fluoroquinolones in pediatric population in Taiwan.

METHODS

Patients aged 0~18 years old with fluoroquinolones prescriptions ≥5 consecutive days during year 2000 to 2013 were selected from the National Health Insurance Research Database, 4-time case number were selected as controls. We evaluated the patient's outcome after the use of fluoroquinolones by reviewing a newly diagnosis of the following collagen-associated adverse events by International Classification of Diseases, Ninth Revision, Clinical Modification codes, covering tendons rupture, retinal detachments, gastrointestinal tract perforation, aortic aneurysm or dissection.

RESULTS

Of the enrolled patients (n = 167,105), collagen-associated adverse effects developed in 85 cases (0.051%) in 6-month tracking, including 0.051% in the fluoroquinolones study cohort (17 in 33,421) and 0.051% (68 in 133,684) in the fluoroquinolones free comparison cohort. The crude hazard ratio for collagen-associated adverse events in the fluoroquinolones group was 0.997 (0.586-1.696; p = 0.990). After adjusting for age, sex, catastrophic illness, low-income household, seasons, levels of urbanization, and healthcare, the corrected hazard ratio in 6-month tracking with FQs was 1.330 (95% CI; 0.778-2.276; p = 0.255).

CONCLUSIONS

There is no significant difference of collagen-associated adverse effects between fluoroquinolones group and fluoroquinolones free group from our data. We propose that fluoroquinolones for pediatric population in clinical practice may be not so harmful as previous references reported.

The role of estrogen in intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) is a main contributor to low back and radicular pain, which imposes heavy economic burdens on society. However, the etiology and mechanism of IVDD are complex and still not completely clear. In particular, the role of estrogen in IVDD has not received much attention in recent research, although estrogen plays a crucial role in the metabolic dysfunction of others musculoskeletal structures, such as bone, muscle, and tendon. In this review, we attempt to describe the role of estrogen in IVDD and to summarize the proposed mechanisms in vivo and in vitro, as well as, to outline several interesting questions in this field.

Extracellular matrix, regional heterogeneity of the aorta, and aortic aneurysm

Aortic aneurysm is an asymptomatic disease with dire outcomes if undiagnosed. Aortic aneurysm rupture is a significant cause of death worldwide. To date, surgical repair or endovascular repair (EVAR) is the only effective treatment for aortic aneurysm, as no pharmacological treatment has been found effective. Aortic aneurysm, a focal dilation of the aorta, can be formed in the thoracic (TAA) or the abdominal (AAA) region; however, our understanding as to what determines the site of aneurysm formation remains quite limited. The extracellular matrix (ECM) is the noncellular component of the aortic wall, that in addition to providing structural support, regulates bioavailability of an array of growth factors and cytokines, thereby influencing cell function and behavior that ultimately determine physiological or pathological remodeling of the aortic wall. Here, we provide an overview of the ECM proteins that have been reported to be involved in aortic aneurysm formation in humans or animal models, and the experimental models for TAA and AAA and the link to ECM manipulations. We also provide a comparative analysis, where data available, between TAA and AAA, and how aberrant ECM proteolysis versus disrupted synthesis may determine the site of aneurysm formation.

A review of aneurysm formation, swelling in blood vessel, in the aorta, examines distinctions between two forms of the condition and the role of proteins in the extracellular matrix which surrounds cells of the arterial wall. Rupture of aneurysms in the aorta, the body’s main artery, is a major cause of death. Researchers led by Zamaneh Kassiri at the University of Alberta, Edmonton, Canada, emphasize that aneurysms in the thoracic and abdominal regions of the aorta are distinct conditions with crucial differences in their causes. Disrupted production and assembly of the extracellular matrix and its proteins may underlie thoracic aneurysm formation. Factors triggering the degradation of extracellular matrix proteins may be more significant in abdominal aneurysms. Understanding the differing molecular mechanisms involved could help address the current lack of effective drug treatments for these dangerous conditions.

Fluoroquinolones and Aortic Diseases: Is There a Connection

Fluoroquinolones (FQs) are one of the most commonly prescribed classes of antibiotics. Their high tissue distribution and broad-spectrum antibacterial coverage make their use very attractive in numerous infectious diseases. Although generally well tolerated, FQs have been associated with different adverse effects including dysglycemia and arrhythmias. FQs have been also associated with a series of adverse effects related to collagen degradation, such as Achilles tendon rupture and retinal detachment. Recently, an association between consumption of FQs and increased risk of aortic aneurysm and dissection has been proposed. This article reviews the pathogenesis of thoracic aortic diseases, the molecular mechanism of FQ-associated collagen toxicity, and the possible contribution of FQs to aortic diseases.

Effects of TNFR1 gene silencing on early apoptosis of marbofloxacin-treated chondrocytes from juvenile dogs

Quinolones (QNs)-induced cartilaginous lesions in juvenile animals by chondrocyte apoptosis is an important toxic effect, which results in the restriction of their use in pediatrics. However, limited data about QNs chondrotoxicity are available for evaluation of the potential toxicity in both animals and human cartilage. To explore whether tumor necrosis factor/its receptor (TNF/TNFR1) signaling pathway is involved in the early apoptosis of marbofloxacin-induced chondrocytes, canine juvenile chondrocytes were treated with 0, 20, 50 and 100 μg/mL marbofloxacin. Results showed that the apoptosis rates of the chondrocytes at 2, 8 and 24 h were significantly increased in a concentration- and time-dependent manner (P <  0.05). The mRNA levels of apoptosis-related factors in TNF/TNFR1 signaling pathways and the protein levels of TNFα and TNFR1 were increased in canine chondrocytes treated with 20-100 μg/mL marbofloxacin (P <  0.05) while TNFR1 gene silencing significantly decreased the chondrocyte apoptosis and inhibited the mRNA expression of TNF/TNFR1 downstream signaling molecules after 100 μg/mL marbofloxacin treatment at 8 h (P <  0.01). It was confirmed that activated TNF/TNFR1 signaling pathway may play a leading role in the early apoptosis of marbofloxacin-induced canine juvenile chondrocytes, which is helpful for clinical estimation or prevention of the risk of QNs.

Determination of two fluoroquinolones and their combinations with hyaluronan effect in in vitro canine cartilage explants

Background

Previous studies reported the effect of enrofloxacin (Enro) and marbofloxacin (Mar) on cell death and alteration of the key genes involved in catabolic and anabolic processes and demonstrated the beneficial effects of hyaluronan (HA) combined with fluoroquinolones (FQs) on primary canine chondrocytes. This study further determines the effects of these treatments on canine cartilage explants in both normal and interleukin-1 beta (IL-1β)-stimulated conditions.

Methods

We examined sulfate glycosaminoglycan (s-GAG) release, uronic acid (UA) content, and safranin-O staining, as well as the expression patterns of inflammatory, extracellular matrix (ECM) component and enzymes.

Results

Enro treatment alone effectively stimulated proteoglycan anabolism by increasing UA content and glycosaminoglycans (GAGs) in normal and pre-IL-1β-stimulated explant, whereas Mar showed opposite results. The combination of HA and FQs increased s-GAG release and UA content in normal explants in addition to effective down-regulated expression of MMP3. HA reduced the adverse effects of Mar by enhancing UA and GAG contents in both normal and pre-IL-1β-explants. Moreover, HA effectively induced HAS1and ACANup-regulation and reduced MMP9, TNF, PTGS2,and NFKB1 expression for a long term.

Discussion

Our results suggest the direct effects of Enro and Mar may selectively stimulate the conditioned explants to express MMP-codinggenes and promote gene expression involved in matrix production, pro-inflammatory cytokines, and cell degradation in different directions. HA successfully reduced the adverse effects of FQs by enhancing s-GAG and UA contents and down-regulated expression of MMPs.

Cytotoxicity of Ciprofloxacin and Steroids in Mouse Tympanic Membrane Fibroblasts

Objective

Ciprofloxacin, commonly given as eardrops, has been shown to adversely affect tympanic membrane fibroblasts. Dexamethasone potentiates this effect. A newly available eardrop contains ciprofloxacin and fluocinolone, a more potent steroid. We evaluated the cytotoxic effects of this preparation on mouse tympanic membrane fibroblasts.

Study Design

Prospective, in vitro.

Setting

Academic laboratory.

Subjects and Methods

In experiment 1, fibroblasts were exposed to 1:10 dilutions of commercially available 0.3% ofloxacin, 0.3% ciprofloxacin, 0.3% ciprofloxacin + 0.1% dexamethasone, 0.3% ciprofloxacin + 0.025% fluocinolone, or dilute hydrochloric acid (control), twice within 24 hours. In experiment 2, cells were also treated with the dilutions of the pure form of dexamethasone 0.1% or fluocinolone 0.025%, alone and in combination with ofloxacin or ciprofloxacin. Cells were exposed to the solutions for 2 hours each time and were placed back in growth media after the treatments. Cells were observed with phase-contrast microscope until the cytotoxicity assay was performed.

Results

Survival of fibroblasts treated with ofloxacin was not different from the control. Fibroblasts treated with ciprofloxacin, ciprofloxacin + dexamethasone, or ciprofloxacin + fluocinolone had much lower survival (all P < .0001). Cells treated with ciprofloxacin + fluocinolone had lower survival than ciprofloxacin ( P < .0001) and ciprofloxacin + dexamethasone ( P = .0001). Steroids alone also decreased fibroblast survival compared to control ( P < .0001). The combination of dexamethasone or fluocinolone with ciprofloxacin, but not ofloxacin, further decreased fibroblast survival ( P < .0001). Phase-contrast images mirrored the cytotoxicity findings.

Conclusion

Tympanic membrane fibroblast cytotoxicity of ciprofloxacin is potentiated by corticosteroids. This effect may be deleterious when treating a healing perforation but beneficial when treating granulation tissue on the tympanic membrane.

Two Unique Cases of Ciprofloxacin-Associated Avulsion of Ligament and Tendon

Ciprofloxacin is recognized to have a deleterious relationship with tendons, particularly Achilles tendinopathy, which makes up most case reports. Tendinopathy seems to occur because of induction of collagen-degrading enzymes causing damage and ischemia of the poorly vascularized regions preventing repair. The focus on the relationship of ciprofloxacin and the Achilles tendon leaves patients on fluoroquinolones with non-Achilles tendinopathy symptoms at risk of misdiagnosis. There have not been any documented instances of ligament damage with ciprofloxacin administration in the literature, although ligament and tendon compositions are similar and should have similar susceptibility. This report includes two cases, one presenting with right lateral thumb pain and a medical history of gastroenteritis treated with ciprofloxacin. Physical examination showed swelling of the right metacarpophalangeal joint and ultrasound confirmed disruption of the radial collateral ligament at insertion on first metacarpal; the second case is of a woman presenting with right hip pain in setting of chronic recurrent diverticulitis treated with ciprofloxacin. She received work-up for lumbar disc disease and spondylosis. After standard therapy with pharmacotherapy and physical therapy for radiculopathy failed, magnetic resonance imaging was performed showing near complete avulsion of the right hamstring tendons from the ischial tuberosity.

Early postoperative fluoroquinolone use is associated with an increased revision rate after arthroscopic rotator cuff repair

PURPOSE

To evaluate the association of postoperative fluoroquinolone use following arthroscopic primary rotator cuff repair with failure requiring revision rotator cuff repair.

METHODS

An insurance database was queried for patients undergoing rotator cuff repair from 2007 to 2015. These patients were divided into three groups: (1) patients prescribed fluoroquinolones within 6 months postoperatively (divided into 0-2, 2-4, and 4-6 months), (2) a matched negative control cohort of patients not prescribed fluoroquinolones, and (3) a matched positive control cohort of patients prescribed fluoroquinolones between 6 and 18 months following rotator cuff repair. Rates of failure requiring revision rotator cuff repair were compared within 2 years.

RESULTS

A total of 1292 patients were prescribed fluoroquinolones within 6 months after rotator cuff repair, including 442 within 2 months, 433 within 2 to 4 months, and 417 within 4 to 6 months, and were compared to 5225 matched negative controls and 1597 matched positive controls. The rate of revision rotator cuff repair was significantly higher in patients prescribed fluoroquinolones within 2 months (6.1 %) compared to matched negative (2.2 %, P = 0.0009) and positive controls (2.4 %, P = 0.0026). There were no significant differences in the rate of revision rotator cuff repair when fluoroquinolones were prescribed >2 months after rotator cuff repair.

CONCLUSIONS

Early use of fluoroquinolones following rotator cuff repair was independently associated with significantly increased rates of failure requiring revision rotator cuff repair. This is the first clinical study examining the association of postoperative fluoroquinolone use with failure following arthroscopic rotator cuff repair.

LEVEL OF EVIDENCE

III.

Triceps Ruptures After Fluoroquinolone Antibiotics: A Report of 2 Cases

Rupture of the triceps brachii tendon is exceedingly rare, and surgical repair is generally indicated. Fluoroquinolone antibiotics have been implicated in tendon pathology, including tendon ruptures. Triceps rupture has not been previously reported in the setting of fluoroquinolone antibiotic therapy. We present 2 cases of triceps tendon rupture after treatment with fluoroquinolones. In both cases, triceps repair was performed with good outcomes. These cases highlight a risk of fluoroquinolone-induced tendinopathy to athletes. The sports medicine team should be aware of this risk and consider it when choosing antibiotics to treat athletes.

Non-insertional Achilles tendinopathy

Non-insertional Achilles tendinopathy is a degenerative condition characterised by pain on activity.Eccentric stretching is the most effective treatment.Surgical treatment is reserved for recalcitrant cases.Minimally-invasive and tendinoscopic treatments are showing promising results. Cite this article: Pearce CJ, Tan A. Non-insertional Achilles tendinopathy. EFORT Open Rev 2016;1:383-390. DOI: 10.1302/2058-5241.1.160024.

Assessing the potential of pharmaceuticals and their transformation products to cause mutagenic effects: Implications for gene expression profiling

The selection and prioritization of pharmaceuticals and their transformation products for evaluating effects on the environment and human health is a challenging task. One common approach is based on compounds (e.g., mixture composition, concentrations), and another on biology (e.g., relevant endpoint, biological organizational level). Both of these approaches often resemble a Lernaean Hydra-they can create more questions than answers. The present study embraces this complexity, providing an integrated approach toward assessing the potential effects of transformation products of pharmaceuticals by means of mutagenicity, estrogenicity, and differences in the gene expression profiles. Mutagenicity using the tk kinase assay was applied to assess a list of 11 priority pharmaceuticals, namely, atenolol, azithromycin, carbamazepine, diclofenac, ibuprofen, erythromycin, metoprolol, ofloxacin, propranolol, sulfamethoxazole, and trimethoprim. The most mutagenic compounds were found to be β-blockers. In parallel, the photolabile pharmaceuticals were assessed for their mixture effects on mutagenicity (tk assay), estrogenicity (T47D- KBluc assay), and gene expression (microarrays). Interestingly, the mixtures were mutagenic at the µg/L level, indicating a synergistic effect. None of the photolysed mixtures were statistically significantly estrogenic. Gene expression profiling revealed effects related mainly to certain pathways, those of the p53 gene, mitogen-activated protein kinase, alanine, aspartate, and glutamate metabolism, and translation-related (spliceosome). Fourteen phototransformation products are proposed based on the m/z values found through ultra-performance liquid chromatography-tandem mass spectrometry analysis. The transformation routes of the photolysed mixtures indicate a strong similarity with those obtained for each pharmaceutical separately. This finding reinforces the view that transformation products are to be expected in naturally occurring mixtures. Environ Toxicol Chem 2016;35:2753-2764. © 2016 SETAC.

Ciprofloxacin Decreases Collagen in Mouse Tympanic Membrane Fibroblasts

Objectives

To determine how collagen production by tympanic membrane fibroblasts is affected by ciprofloxacin at levels found in eardrops.

Study Design

Prospective, controlled, and blinded cell culture study.

Setting

Academic tertiary medical center.

Subjects

Cell culture of mouse fibroblasts.

Methods

A primary fibroblast culture was established from mouse tympanic membranes. Fibroblasts were cultured until they were 75% confluent, then treated with dilute hydrochloric acid (control) or ciprofloxacin (0.01% or 0.3%) for 24 or 72 hours for Western blotting and for 24 or 48 hours for cytotoxicity assay. Cells were observed with phase-contrast microscope. Western blotting was performed for collagen type 1 α1 (collagen 1A1) and α-tubulin.

Results

Fibroblasts treated with 0.01% and 0.3% ciprofloxacin for 24 hours had lower levels of collagen 1A1 ( P = .0005 and P < .0001, respectively) and α-tubulin (both P < .0001) than control fibroblasts. Collagen 1A1 and α-tubulin levels were lower in fibroblasts treated with 0.3% than with 0.01% ciprofloxacin ( P = .02 and P = .014). After 72 hours, 0.3% ciprofloxacin completely eliminated collagen 1A1 and α-tubulin ( P < .001). Cells treated with 0.01% ciprofloxacin for 72 hours also had lower collagen 1A1 ( P < .0001) and α-tubulin ( P = .005) as compared with the control. Seventy-two-hour incubation in 0.01% or 0.3% ciprofloxacin resulted in lower levels of collagen 1A1 ( P = .009 and P < .0001, respectively) and α-tubulin ( P = .007 and P < .0001, respectively) than 24-hour incubation. Cytotoxicity assay and phase-contrast microscopy mirrored these findings.

Conclusions

Treatment of tympanic membrane fibroblasts with 0.3% ciprofloxacin, as found in eardrops, reduces fibroblast viability and collagen and α-tubulin protein levels. These findings could explain tympanic membrane healing problems associated with quinolone eardrops.

Predictors of primary Achilles tendon ruptures

BACKGROUND

The Achilles tendon is the strongest tendon in the human body. The incidence of Achilles tendon ruptures appears to be increasing.

OBJECTIVES

The aim of this review was to systematically summarize predictors influencing Achilles tendon rupture (ATR) risk.

METHODS

A systematic literature search was performed of reported determinants influencing the ATR risk. Studies were eligible if there was: (i) description of determinants predicting ATR; (ii) an outcome defined as ATR; (iii) any study design with at least ten adults included with ATR; (iv) use of statistical tests regarding differences between patients with an ATR and healthy controls; (v) a full text article available; (vi) an article written in English, German or Dutch. Quality assessment was done using a standardized criteria set. Best-evidence synthesis was performed.

RESULTS

We included 31 studies, of which two (6.5%) were considered high-quality studies. Moderate evidence was found for increased ATR risk and decreased fibril size of Achilles tendon.

CONCLUSION

Based on the results of this systematic review there is moderate evidence that decreased tendon fibril size increases the ATR risk. There is limited evidence for many other factors, some of which are modifiable, such as increased body weight, oral corticosteroid use and quinolone use and living in an urban area, and therefore may be of interest in future studies. Furthermore, these results showed that more high-quality studies are needed for evaluating the determinants influencing the ATR risk.

Fluoroquinolones impair tendon healing in a rat rotator cuff repair model: a preliminary study

BACKGROUND

Recent studies suggest that fluoroquinolone antibiotics predispose tendons to tendinopathy and/or rupture. However, no investigations on the reparative capacity of tendons exposed to fluoroquinolones have been conducted.

HYPOTHESIS

Fluoroquinolone-treated animals will have inferior biochemical, histological, and biomechanical properties at the healing tendon-bone enthesis compared with controls.

STUDY DESIGN

Controlled laboratory study.

METHODS

Ninety-two rats underwent rotator cuff repair and were randomly assigned to 1 of 4 groups: (1) preoperative (Preop), whereby animals received fleroxacin for 1 week preoperatively; (2) pre- and postoperative (Pre/Postop), whereby animals received fleroxacin for 1 week preoperatively and for 2 weeks postoperatively; (3) postoperative (Postop), whereby animals received fleroxacin for 2 weeks postoperatively; and (4) control, whereby animals received vehicle for 1 week preoperatively and for 2 weeks postoperatively. Rats were euthanized at 2 weeks postoperatively for biochemical, histological, and biomechanical analysis. All data were expressed as mean ± standard error of the mean (SEM). Statistical comparisons were performed using either 1-way or 2-way ANOVA, with P < .05 considered significant.

RESULTS

Reverse transcriptase quantitative polymerase chain reaction (RTqPCR) analysis revealed a 30-fold increase in expression of matrix metalloproteinase (MMP)-3, a 7-fold increase in MMP-13, and a 4-fold increase in tissue inhibitor of metalloproteinases (TIMP)-1 in the Pre/Postop group compared with the other groups. The appearance of the healing enthesis in all treated animals was qualitatively different than that in controls. The tendons were friable and atrophic. All 3 treated groups showed significantly less fibrocartilage and poorly organized collagen at the healing enthesis compared with control animals. There was a significant difference in the mode of failure, with treated animals demonstrating an intrasubstance failure of the supraspinatus tendon during testing. In contrast, only 1 of 10 control samples failed within the tendon substance. The healing enthesis of the Pre/Postop group displayed significantly reduced ultimate load to failure compared with the Preop, Postop, and control groups. There was no significant difference in load to failure in the Preop group compared with the Postop group. Pre/Postop animals demonstrated significantly reduced cross-sectional area compared with the Postop and control groups. There was also a significant reduction in area between the Preop and control groups.

CONCLUSION

In this preliminary study, fluoroquinolone treatment negatively influenced tendon healing.

CLINICAL RELEVANCE

These findings indicate that there was an active but inadequate repair response that has potential clinical implications for patients who are exposed to fluoroquinolones before tendon repair surgery.

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.

Toxic effects of levofloxacin on rat annulus fibrosus cells: an in-vitro study

BACKGROUND

Fluoroquinolones are in wide clinical use as safe and effective antibiotics. Articular cartilage, tendons, and epiphyseal growth plates have been recognized as targets of fluoroquinolone-induced connective tissue toxicity. However, the effects of fluoroquinolones on annulus fibrosus (AF) cells are still unknown.

MATERIAL/METHODS

The main objective of this study was to investigate the effects of levofloxacin, a typical fluoroquinolone antibiotic drug, on rat AF cells in vitro. Rat annulus fibrosus (RAF) cells were treated with levofloxacin at different concentrations (0, 10, 20, 30, 40, 60, 80, and 90 μg/ml) and were assessed to determine the possible cytotoxic effects of levofloxacin. Inverted phase-contrast microscopy was used to accomplish the morphological observation of apoptosis of treated cells. Western blot and real-time quantitative RT-PCR (qPCR) was used to explore the expression of active caspase-3 and MMP-3. Flow cytometry was used to measure the apoptotic incidences.

RESULTS

Our study showed that levofloxacin, with concentrations at 30, 60, and 90 μg/ml, induced dose-dependent RAF cell apoptosis and higher expression of caspase-3 and MMP-3. More apoptotic cells were observed by inverted phase-contrast microscopy. Moreover, levofloxacin increased the activity of caspase-3, and it also reduced cell viability with different concentrations ranging from 10 to 80 μg/ml.

CONCLUSIONS

Our study results suggest that levofloxacin has cytotoxic effects on RAF cells, characterized by enhancing apoptosis and reducing cell viability, and indicate a potential toxic effect of fluoroquinolones on RAF cells.

Ciprofloxacin-induced tendinopathy of the gluteal tendons

Fluoroquinolone-induced tendinopathy most commonly affects the Achilles tendon; however, involvement of several other tendons has been described. This is a case report of ciprofloxacin-induced tendinopathy of the gluteal tendons with MRI findings. An obese 25-year-old woman with no significant past medical history was diagnosed with acute pyelonephritis and was treated with intravenous ciprofloxacin. Shortly after her first dose of ciprofloxacin, she developed severe left hip pain and decreased range of motion. MRI of the hips showed bilateral tendinopathy of the gluteal muscle insertion. A diagnosis of ciprofloxacin-induced tendinopathy was made based on her MRI and a Naranjo score of 7. Ciprofloxacin was stopped and her pain quickly resolved. Fluoroquinolones cause tendinopathy in 0.14 % to 0.4 % of patients using these agents. Fluoroquinolone-associated tendinopathy is a serious adverse reaction that can affect many tendons and should be considered in any patient presenting with new musculoskeletal complaints and in whom there is a history of fluoroquinolone use within the preceding 6 months.

Levofloxacin increases the effect of serum deprivation on anoikis of rat nucleus pulposus cells via Bax/Bcl-2/caspase-3 pathway

Levofloxacin, a fluoroquinolone, is a widely-used and effective antibiotic. However, various adverse side effects are associated with levofloxacin. The purpose of this study was to further explore the effects of levofloxacin on rat nucleus pulposus cells (NPCs). Inverted phase-contrast microscopy, flow cytometry and caspase-3 activity assays were used and revealed that serum deprivation induced apoptosis, which was markedly increased by levofloxacin in a dose-dependent manner. Simultaneously, levofloxacin decreased cell binding to type II collagen (COL2). Thus, levofloxacin-induced apoptosis exhibits characteristics of anoikis, the process by which cell death is triggered by separation from the extracellular matrix, which contains COL2. Furthermore, real-time quantitative RT-PCR was used to further confirm that levofloxacin downregulates COL2 expression in a dose-dependent manner. At last, western blot was used to find that levofloxacin increased the ratio of Bax/Bcl-2 and active caspase-3 in a dose-dependent manner. Levofloxacin therefore increases the effects of serum deprivation on anoikis by downregulating COL2 in rat NPCs in vitro via Bax/Bcl-2/caspase-3 pathway. This research provides a novel insight into the mechanisms of levofloxacin-induced toxicity and may potentially lead to a better understanding of the clinical effects of levofloxacin, especially in terms of intervertebral disc degeneration.

TNF/TNFR₁ pathway and endoplasmic reticulum stress are involved in ofloxacin-induced apoptosis of juvenile canine chondrocytes

BACKGROUND AND PURPOSE

Quinolones cause obvious cartilaginous lesions in juvenile animals by chondrocyte apoptosis, which results in the restriction of their use in pediatric and adolescent patients. Studies showed that chondrocytes can be induced to produce TNFα, and the cisternae of the endoplasmic reticulum in quinolone-treated chondrocytes become dilated. We investigated whether TNF/TNFR₁ pathway and endoplasmic reticulum stress (ERs) are involved in ofloxacin (a typical quinolone)-induced apoptosis of juvenile canine chondrocytes.

EXPERIMENTAL APPROACH

Canine juvenile chondrocytes were treated with ofloxacin. Cell survival and apoptosis rates were determined with MTT method and flow cytometry, respectively. The gene expression levels of the related signaling molecules (TNFα, TNFR₁, TRADD, FADD and caspase-8) in death receptor pathways and main apoptosis-related molecules (calpain, caspase-12, GADD153 and GRP78) in ERs were measured by qRT-PCR. The gene expression of TNFR₁ was suppressed with its siRNA. The protein levels of TNFα, TNFR₁ and caspase-12 were assayed using Western blotting.

KEY RESULTS

The survival rates decreased while apoptosis rates increased after the chondrocytes were treated with ofloxacin. The mRNA levels of the measured apoptosis-related molecules in death receptor pathways and ERs, and the protein levels of TNFα, TNFR₁ and caspase-12 increased after the chondrocytes were exposed to ofloxacin. The downregulated mRNA expressions of TNFR₁, Caspase-8 and TRADD, and the decreased apoptosis rates of the ofloxacin-treated chondrocytes occurred after TNFR₁-siRNA interference.

CONCLUSIONS AND IMPLICATIONS

Ofloxacin-induced chondrocyte apoptosis in a time- and concentration-dependent fashion. TNF/TNFR₁ pathway and ERs are involved in ofloxacin-induced apoptosis of juvenile canine chondrocytes in the early stage.

Induced osteoclastogenesis by fluoroquinolones in unstimulated and stimulated human osteoclast precursor cells

Fluoroquinolones (FQs) are a class of antibiotics with a broad spectrum of activity, known to disturb bone metabolism. The aim of this work was to characterize the cellular and molecular effects of five FQs (ofloxacin, norfloxacin, ciprofloxacin, levofloxacin and moxifloxacin) in unstimulated and stimulated human osteoclast precursors. Peripheral blood mononuclear cells (PBMC) were cultured in the absence (unstimulated) or in the presence of osteoclastogenic factors (M-CSF and RANKL, stimulated), and were treated with FQs (0.3×10(-9)-10(-3) M), for 21 days. In unstimulated PBMC cultures, FQs (excepting moxifloxacin) exhibited a high osteoclastogenic potential, as shown by a significant increase in the expression of osteoclastic genes, TRAP activity and, specially, number of TRAP-positive multinucleated cells and calcium phosphate resorbing ability, suggesting the presence of mature and functional osteoclasts. Norfloxacin and levofloxacin induced the higher effect, followed by ciprofloxacin and ofloxacin. A decrease on apoptosis and an increase on M-CSF expression might have a possible contribution in the observed cellular behavior. In stimulated PBMC cultures, FQs further increase the osteoclastogenic response induced by M-CSF and RANKL (except ofloxacin). However, the osteoclastogenic response was much lower than that observed in unstimulated PBMC cultures. Both in unstimulated and stimulated PBMC cultures, for most of the FQs, the osteoclastogenic effects were observed in a wide range of concentrations, representative of plasmatic and tissue levels attained in several clinical settings. The various FQs differed on the stimulatory concentration range, the extent of the induced osteoclastogenic response and, also, on the dose- and time-dependent profile. Nevertheless, at high concentrations all the FQs seemed to elicit an increase on apoptosis. Additionally, some differences were noted in the intracellular signaling pathways tested, namely NFkB, MEK and PGE2 production. Results suggest that, considering the inter-individual variability of the FQs pharmacokinetics, the detailed biological profile of each FQ on bone cells is of utmost importance to clarify the effects of these compounds on bone metabolism.

Three-dimensional high-density co-culture with primary tenocytes induces tenogenic differentiation in mesenchymal stem cells

Mesenchymal stem cells (MSCs) have potential applications in regenerative medicine and tissue engineering and may represent an attractive option for tendon repair and regeneration. Thus far the ability of MSCs to differentiate into tenocytes in vitro has not been investigated. Experiments were performed with and without growth factors (IGF-1, TGF-β1, IGF-1/TGF-β1, PDGF-BB, and BMP-12), in co-cultures of tenocytes and MSCs mixed in different ratios and by culturing MSCs with spent media obtained from primary tenocytes. Tenogenesis was induced in MSCs through a combination of treatment with IGF-1 and TGF-β1, in high-density co-cultures and through cultivation with the spent media from primary tenocytes. Electron microscopy and immunoblotting were used to demonstrate up-regulation of collagen I/III, decorin, tenomodulin, β1-Integrin, MAPKinase pathway (Shc, Erk1/2), and scleraxis in the co-cultures and provide simultaneous evidence for the inhibition of apoptosis. In monolayer co-cultures extensive intercellular contacts between MSCs and tenocytes were observed. Cells actively exchanged vesicles, which were labeled by using immunofluorescence and immunogold techniques, suggesting the uptake and interchange of soluble factors produced by the MSCs and/or tenocytes. We conclude that MSCs possess tenogenic differentiation potential when provided with relevant stimuli and a suitable microenvironment. This approach may prove to be of practical benefit in future tissue engineering and tendon regenerative medicine research.

Curcumin modulates nuclear factor kappaB (NF-kappaB)-mediated inflammation in human tenocytes in vitro: role of the phosphatidylinositol 3-kinase/Akt pathway

Inflammatory processes play essential roles in the pathogenesis of tendinitis and tendinopathy. These events are accompanied by catabolic processes initiated by pro-inflammatory cytokines such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Pharmacological treatments for tendinitis are restricted to the use of non-steroidal anti-inflammatory drugs. Recent studies in various cell models have demonstrated that curcumin targets the NF-κB signaling pathway. However, its potential for the treatment of tendinitis has not been explored. Herein, we used an in vitro model of human tenocytes to study the mechanism of curcumin action on IL-1β-mediated inflammatory signaling. Curcumin at concentrations of 5-20 μm inhibited IL-1β-induced inflammation and apoptosis in cultures of human tenocytes. The anti-inflammatory effects of curcumin included down-regulation of gene products that mediate matrix degradation (matrix metalloproteinase-1, -9, and -13), prostanoid production (cyclooxygenase-2), apoptosis (Bax and activated caspase-3), and stimulation of cell survival (Bcl-2), all known to be regulated by NF-κB. Furthermore, curcumin suppressed IL-1β-induced NF-κB activation via inhibition of phosphorylation and degradation of inhibitor of κBα, inhibition of inhibitor of κB-kinase activity, and inhibition of nuclear translocation of NF-κB. Furthermore, the effects of IL-1β were abrogated by wortmannin, suggesting a role for the phosphatidylinositol 3-kinase (PI-3K) pathway in IL-1β signaling. Curcumin suppressed IL-1β-induced PI-3K p85/Akt activation and its association with IKK. These results demonstrate, for the first time, a potential role for curcumin in treating tendon inflammation through modulation of NF-κB signaling, which involves PI-3K/Akt and the tendon-specific transcription factor scleraxis in tenocytes.

Musculoskeletal complications of fluoroquinolones: guidelines and precautions for usage in the athletic population

Fluoroquinolone antibiotics are associated with a wide spectrum of musculoskeletal complications that involve not only tendon but also cartilage, bone, and muscle. Insights into the pathoetiology of fluoroquinolone toxicity on musculoskeletal tissues have been evolving over recent years. Although the pathoetiology is certainly multifactorial, alterations in cell signaling proteins and direct toxic effects on musculoskeletal tissues have been strongly implicated. Increasing age and concomitant systemic corticosteroid use appear to significantly increase the risk of adverse events. The purpose of this article is to review the musculoskeletal complications associated with use of fluoroquinolone antibiotics by adults; identify risk factors associated with fluoroquinolone toxicity; explore the possible pathoetiology of fluoroquinolone toxicity on tendon, cartilage, bone, and muscle; and offer recommendations regarding evaluation and treatment of fluoroquinolone-associated musculoskeletal complications. In addition, this review will provide recommendations regarding fluoroquinolone use in athletes and return to play after fluoroquinolone exposure.

Ciprofloxacin utility as antifibrotic in the skin of patients with scleroderma

Scleroderma is an autoimmune connective tissue disorder that is characterized by microvascular injury, excessive fibrosis of the skin, and distinctive visceral changes that can involve the lungs, heart, kidneys and gastrointestinal tract. To date, although several drugs have been used to reduce fibrosis in scleroderma, there exists no effective pharmacological treatment. To determine if oral ciprofloxacin reduces the severity of scleroderma, a controlled, double-blind randomized clinical trial, with placebo, was conducted on 32 patients with diffuse and limited scleroderma, who received oral ciprofloxacin (250 mg) or placebo every 12 h. Skin induration and thickness of the patients were clinically evaluated using the modified Rodnan skin score at the beginning and once per month during 6 months of treatment with ciprofloxacin. To monitor progression of the disease, a monthly hematological exam and clinical evaluation was done to explore renal and hepatic function for each patient. Thirty patients completed the study; one from the treatment group was excluded when presenting a skin reaction and another from the placebo group abandoned the study due to an exacerbation of disease. At the sixth month of the study, the ciprofloxacin group of patients showed a diminution in the modified Rodnan skin score (58% vs 18%, P = 0.003), showing no significant alterations in the laboratory assays in either groups of patients. Our results suggest that oral administration of ciprofloxacin for 6 months reduces the severity of symptoms affecting the skin of patients with systemic scleroderma, and does so without important secondary effects.