Toxic effects of quinolone antibacterial agents on the musculoskeletal system in juvenile rats

TOL19-001 reduces inflammation and MMP expression in monolayer cultures of tendon cells

Background

Tendinopathies are tendon conditions associated with degeneration and disorganization of the matrix collagen fibers, tendon cells apoptosis and inflammation through up-regulation of proinflammatory cytokines, matrix metalloproteinase (MMP) expression, and prostaglandin E₂ (PGE₂) production. Currently, the pharmacological treatment is mainly based on non-steroidal anti-inflammatory drugs (NSAIDs) use and corticosteroid injections, which both can lead to numerous side effects for patients. TOL19-001 is a diet supplementary composed mostly of spirulina and glucosamine sulfate whose antioxidant properties could be helpful to treat tendinopathies while avoiding taking NSAIDs. In this study we developed an in vitro model of tendinopathy in order to evaluate the therapeutic potential of TOL19-001.

Methods

Tendon cells were cultured on monolayer and treated with interleukin-1β (IL-1β) or ciprofloxacin (CIP), and then, MMPs, PGE2 and collagen expression was evaluated by RT-PCR or Elisa. In addition, a cotreatment with increased doses of TOL19-001 was done. Toxicity of TOL19-001 was evaluated using a metabolic activity assay.

Results

This study demonstrates that IL-1β mimics some aspects of tendinopathies with PGE2 induction, MMP expression (mostly MMP1 and MMP3), and increases of type III/I collagen ratio. CIP, meanwhile, leads to an increase of MMP2 and p65 mRNA, whereas it reduces TIMP1 expression. Scleraxis expression was also increased by CIP whereas it was decreased by IL-1β treatment. Besides, TOL19-001 cotreatment suppresses tendon cell inflammation in vitro, marked by the downregulation of PGE2, MMPs and type III collagen in IL-1β stimulated-cells. TOL19-001 also represses CIP induced-changes.

Conclusions

These findings indicate that TOL19-001 exerts anti-inflammatory effects on tendon cells, which might explain why TOL19-001 diet may improve tendon function in patients with tendon injury. Future research is required to determine TOL19-001 effect on injured or overused tendons in vivo.

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.

Acute rhabdomyolysis associated with coadministration of levofloxacin and simvastatin in a patient with normal renal function

We report a rare case of severe acute rhabdomyolysis in association with coadministration of levofloxacin and simvastatin in a patient with normal renal function. A 70-year-old Caucasian male was treated due to community acquired pneumonia with levofloxacin in a dosage of 500 mg once and then twice a day. On the 8th day of hospitalization the patient presented with acute severe rhabdomyolysis requiring an intensive care support. After discontinuation of levofloxacin and concomitant medication with simvastatin 80 mg/day, clinical and laboratory effects were totally reversible. Up to now, levofloxacin has been reported to induce rhabdomyolysis mainly in patients with impaired renal function, as the medication has a predominant renal elimination. In our case renal function remained normal during the severe clinical course. According to a recent case report rhabdomyolysis was observed due to interaction of simvastatin and ciprofloxacin. To our best knowledge this is the first case of interaction between simvastatin and levofloxacin to be reported. This case emphasizes the need of close monitoring of creatine kinase in patients under more than one potentially myotoxic medication especially when patients develop muscle weakness.

Levofloxacin-induced rhabdomyolysis in a hemodialysis patient

Rhabdomyolysis is a well-known complication of various drug therapies. We report a case of levofloxacin-induced rhabdomyolysis requiring hospitalization in a hemodialysis patient. Physicians should be aware of the risk of this potentially severe adverse drug reaction.

Can oral levofloxacin cause of flexor digitorum profundus rupture?

Fluoroquinolones are broad-spectrum antibacterial agents. Reports of Achilles tendon rupture as a possible side effect of the quinolones have been previously presented but mechanism of the side effect of the medication is still unknown. Tendon rupture in the forearm associated with fluoroquinolone use has not been reported. We present a patient who underwent levofloxacin treatment for skin infections and subsequently developed left small finger flexor digitorum profundus rupture. We propose that this rupture may be related to the side effect of the medication. If it is, clinicians have to be aware of possible tendon ruptures in the upper extremity due to side effects of quinolones and patients have to be informed about it.

Diagnosis and imaging of ankle instability

Ankle instability is a major cause of symptoms following an ankle sprain. With a thorough history and examination, appropriate additional investigations, including cross-sectional imaging, and thoughtful interpretation of the information, one should rarely be caught out by misdiagnosis, multiple diagnoses, or unusual causes.

Ultrastructural changes of the gemifloxacin on Achilles tendon in immature rats: comparison with those of ciproxacin and ofloxacin

Gemifloxacin is a synthetic fluoroquinolone antimicrobial agent that exhibits potent activity against most Gram-negative and Gram-positive organisms, and has a comparatively low chondrotoxic potential in immature animals. This study examined the effects of gemifloxacin on the Achilles tendons in immature Sprague-Dawley rats treated by oral intubation once daily for 5 consecutive days from postnatal week 4 onward at doses of 0 (vehicle), and 600 mg/kg body weight. Ofloxacin or ciprofloxacin were used for comparison. The Achilles tendon specimens were examined by electron microscopy. In comparison with the vehicle-treated controls, there were ultrastructural changes in all samples from the gemifloxacin-, ofloxacin-, and ciprofloxacin-treated rats. Degenerative changes were observed in the tenocytes, and the cells that detached from the extracellular matrix were recognizable. The degree of degenerative changes and the number of degenerated cells in the Achilles tendon were significantly higher in the treated group than in the control group. Moreover, among the quinolone-treated groups, these findings were most significant in the ofloxacin-treated group, and least significant in the gemifloxacin-treated group. It is unclear what these findings mean with respect to the possible risk in juvenile patients treated with gemifloxacin or other quinolones. However, these results show that gemifloxacin causes less changes in the connective tissue structures.

Gemifloxacin for the treatment of respiratory tract infections: in vitro susceptibility, pharmacokinetics and pharmacodynamics, clinical efficacy, and safety

Gemifloxacin is a synthetic fluoroquinolone antimicrobial agent exhibiting potent activity against most gram-negative and gram-positive organisms, such as the important community-acquired respiratory pathogens Streptococcus pneumoniae (including multidrug-resistant S. pneumoniae), Haemophilus influenzae , and Moraxella catarrhalis . The agent's mechanism of action involves dual targeting of two essential bacterial enzymes: DNA gyrase and topoisomerase IV. Gemifloxacin was approved by the Food and Drug Administration in April 2003 for treatment of community-acquired pneumonia and acute bacterial exacerbation of chronic bronchitis. The drug has an oral bioavailability of approximately 71%. Approximately 20-35% of gemifloxacin is excreted unchanged in the urine after 24 hours. The elimination half-life of gemifloxacin is 6-8 hours in patients with normal renal function, supporting once-daily dosing. The 24-hour free-drug area under the plasma concentration-time curve:minimum inhibitory concentration ratio (fAUC(0-24):MIC) associated with efficacy, based on results from in vitro and animal models of infection, is approximately 30. With a mean fAUC(0-24) of approximately 3 microg*hour/ml (35% of total AUC(0-24) of 8.4) and a median S. pneumoniae MIC for 90% of tested strains of 0.03, a fAUC(0-24):MIC ratio of 100 would be expected after standard dosing (320 mg once/day). In clinical studies involving both hospitalized and outpatient populations, gemifloxacin has been highly effective in the treatment of community-acquired pneumonia and acute exacerbation of chronic bronchitis. Clinical success rates ranged from 93.9-95.9% in patients with community-acquired pneumonia and 96.1-97.5% in those with acute exacerbation of chronic bronchitis. Gemifloxacin is well tolerated; the frequency of adverse events with this agent is low. Most adverse events are mild-to-moderate in severity, with diarrhea (< 4%), nausea and rash (< 3%), and headache (< 2%) most commonly reported. Drug interactions with gemifloxacin are not common, although absorption is greatly reduced when given with divalent and trivalent cation-containing compounds, such as antacids. Due to its potent activity against many common gram-positive and gram-negative respiratory pathogens, its proven clinical efficacy, and its favorable safety profile, gemifloxacin is a highly effective empiric treatment for community-acquired lower respiratory tract infections.

Acute Rhabdomyolysis Associated with Ofloxacin/Levofloxacin Therapy

OBJECTIVE:

To report a case of ofloxacin/levofloxacin-induced rhabdomyolysis and to compare other reported cases from the literature.

CASE SUMMARY:

A 19-year-old male patient developed ofloxacin/levofloxacin-induced rhabdomyolysis during admission for periorbital cellulitis. Symptoms of myalgia, weakness, and swelling of the arms developed after 3 days of treatment with ofloxacin 800 mg/day. Laboratory analysis confirmed the presence of urine myoglobin (381.2 μg/L) and a marked increase in serum myoglobin (590.8 μg/L), along with marked elevations in serum creatine kinase (up to 16 546 IU/L).

DISCUSSION:

In addition to ruling out other possible etiologic factors one by one, we assessed the probability of ofloxacin/levofloxacin-induced rhabdomyolysis by observing the close time relationship between drug administration and the development of symptoms/signs, as well as the close time relationship between drug withdrawal and the disappearance of symptoms/signs. An objective causality assessment by use of the Naranjo probability scale revealed that the adverse drug reaction was probable.

CONCLUSIONS:

Although ofloxacin/levofloxacin-induced rhabdomyolysis appears to be rare, patients with muscle pain, swelling, or weakness during therapy should be closely monitored for this adverse effect.

Subacute toxicity and toxicokinetics of a new antibiotic, DW-224a, after single and 4-week repeated oral administration in dogs

The subacute toxicity and toxicokinetics of a new fluoroquinolone antibiotic, DW-224a, were evaluated after single (on the 1st day) and 4-week (on the 28th day) oral administration of the drug at doses of 0 (to serve as a control), 10, 30, and 90 mg/kg/d, to male and female dogs (n=3 for male and female dogs for each dose). During the test period, clinical signs, mortality, body weight, food consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, organ weight and histopathology were examined. The 4-week repeated oral dose of DW-224a resulted in vomiting, salivation, increased serum cholesterol level, and atrophy of thymus and testes. The target organ was determined to be the thymus and testes. The absolute toxic dose of DW-224a was 30 mg/kg and the level at which no adverse effects were observed was 10 mg/kg for both sexes. There were no significant gender differences in the pharmacokinetic parameters of DW-224a for each dose after both single and 4-week oral administration. The pharmacokinetic parameters of DW-224a were dose independent after a single oral administration; the time to reach the peak plasma concentration (T(max)) and the dose-normalized area under the plasma concentration-time curve from time zero to 24 h in plasma (AUC(0-24 h)) were not significantly different among the three doses. The accumulation of DW-224a after 4-week oral administration was not notable at the toxic dose of 90 mg/kg/d. For example, after 4-week administration, the dose-normalized AUC(0-24 h) value at 90 mg/kg/d (7.69, 7.05 microg h/ml) was not significantly greater than that at 10 mg/kg/d. After 4-week oral administration, the dose-normalized C(max) and AUC(0-24 h) at 90 mg/kg/d were not significantly higher and greater, respectively, than those after a single oral administration.

Advances in DNA gyrase inhibitors

The therapeutic use of DNA gyrase inhibitors, mainly quinolone antibacterials, has proven to be a tremendous success story in the treatment of bacterial infections. The rapid changes in quinolone research and development in recent years have produced several new quinolones: moxifloxacin, gatifloxacin, gemifloxacin and des-6-fluoroquinolone antibacterials. These newly developed compounds are equal or superior to existing ones in their potency, spectrum of activity, pharmacodynamics/pharmacokinetics and safety profiles. The recent discovery of non-fluoroquinolones and 2-pyridone antibacterials represents yet additional progress in the search for novel DNA gyrase inhibitors. Although these two classes of compounds are either in the discovery or early development phase, they extend the possibilities of establishing new structure-activity relationships and new chemotypes for DNA gyrase inhibition.

The safety profile of the fluoroquinolones

BACKGROUND

Premarketing trials showed the fluoroquinolone agents to have a favorable side-effect profile, with treatment-related adverse events comprising gastrointestinal, central nervous system, and dermatologic effects that were generally mild and reversible on cessation of treatment. However, postmarketing surveillance studies have identified severe adverse events, including severe anaphylaxis, QTc-interval prolongation, and potential cardiotoxicity, associated with 3 quinolone agents that either resulted in the removal of the agent from the market (temafloxacin and grepafloxacin) or significantly restricted its use due to substantial mortality and morbidity associated with liver toxicity (trovafloxacin). To date, there have been no such significant adverse events associated with the older fluoroquinolone agents, including ciprofloxacin, ofloxacin, norfloxacin, and levofloxacin. However, there are fewer data from postmarketing surveillance studies on the most recently approved agents, such as moxifloxacin and gatifloxacin, or agents awaiting approval, such as gemifloxacin.

OBJECTIVE

This paper examines safety data from the premarketing trials and postmarketing surveillance studies of fluoroquinolones available in the United States.

METHODS

A MEDLINE search was performed to identify all English-language studies published since 1980 concerning the safety profiles of the fluoroquinolones.

CONCLUSIONS

The fluoroquinolone antibacterial agents offer broad-spectrum therapy in patients with a variety of infections. Given similar spectra of activity, the choice between quinolones may be based on differences in efficacy and safety or tolerability profiles. Most drug reactions involving these agents are minor and reversible on discontinuing treatment, but adverse effects can be associated with significant mortality and morbidity, as was seen in the case of trovafloxacin and temafloxacin.

Ultrastructure of Achilles tendons of rats treated with ofloxacin and fed a normal or magnesium-deficient diet

Fluoroquinolones can cause tendinitis and tendon rupture. However, toxicological as well as clinical information on quinolone-induced tendopathy is scarce. We performed extensive electron microscopic studies with Achilles tendon specimens from ofloxacin-treated rats. The drug was given at a dose of 1,200 mg/kg (body weight) orally. Juvenile Wistar rats received one or three oral doses each of 1,200 mg of ofloxacin/kg (body weight)/day. Three days after treatment, the tenocytes of their Achilles tendons showed degenerative alterations, such as multiple vacuoles and vesicles in the cytoplasm that had developed due to swellings and dilatations of cell organelles. Other indications of cell degradation were the occurrence of cell debris and cell detachment from the extracellular matrix accompanied by a loss of cell-matrix interaction. The tenocytes of juvenile Wistar rats that had been treated at day 36 with a single oral dose of 1,200 mg of ofloxacin/kg (body weight) and sacrificed either 3 or 6 months later exhibited similar degenerative alterations. The number of degenerative alterations of tenocytes after ofloxacin treatment was considerably higher in rats that had received a magnesium-deficient diet than in rats with normal magnesium status. Of the adult rats that had been treated once, 5 times, and 10 times with ofloxacin and killed 1 day later, only those with the 10-times treatment showed a significantly increased number of degeneratively altered tenocytes. In summary, effects observed in tendons show similar pathological features as described earlier in cartilage, indicating that quinolone-induced arthropathy and quinolone-induced tendopathy probably are different clinical manifestations of the same toxic effect on cellular components of connective tissue structures.