The effect of aging on migration, proliferation, and collagen expression of tenocytes in response to ciprofloxacin

Use of fluoroquinolones and risk of rhegmatogenous retinal detachment: a retrospective cohort study using two nationwide representative claims databases

Background

Although biological plausibility suggests that fluoroquinolones could lead to rhegmatogenous retinal detachment (RRD) through collagen degradation, real-world evidence on their relative risk of RRD is inconsistent, with limited information on absolute risk estimates.

Objective

The study aimed to estimate the RRD risk associated with fluoroquinolones versus other antibiotics with similar indications (i.e., comparison antibiotics).

Methods

We conducted a retrospective cohort study analyzing claims data from adult patients who initiated fluoroquinolones or amoxicillin/clavulanate or ampicillin/sulbactam or extended-spectrum cephalosporins using the Taiwan National Health Insurance Research Database (2009-2018) and the United States IBM MarketScan Database (2011-2020). Patients were followed for up to 90 days after cohort entry. For each country's data, after 1:1 propensity score (PS) matching, we used Cox regression models to estimate RRD risks, presented with hazard ratios (HR) with 95% confidence interval (95% CI). We used random-effects meta-analyses to derive pooled HRs across both counties.

Results

Of 24,172,032 eligible patients comprising 7,944,620 insured Taiwanese (mean age [SD], 46 [18] years; 45% male) and 16,227,412 United States commercially insured individuals (mean age [SD], 47 [16] years; 40% male), 10,137,468 patients initiated fluoroquinolones, 10,203,794 initiated amoxicillin/clavulanate or ampicillin/sulbactam, and 3,830,770 initiated extended-spectrum cephalosporins. After PS matching, similar RRD incidence rates were observed between fluoroquinolones and amoxicillin/clavulanate or ampicillin/sulbactam users (0.33 [95% CI, 0.19-0.56] versus 0.35 [95% CI, 0.26-0.46] per 1,000 person-years), yielding an HR of 0.97 (95% CI, 0.76-1.23). The RRD incidence rates were also similar comparing fluoroquinolones to extended-spectrum cephalosporins (0.36 [95% CI, 0.22-0.57] versus 0.34 [95% CI, 0.22-0.50] per 1,000 person-years; HR, 1.08 [95% CI, 0.92-1.27]). The comparative safety profiles remained consistent by country, various patient characteristic (e.g., diabetes or ophthalmic conditions), type of fluoroquinolones, follow-up duration, or treatment setting.

Conclusion

This large-scale study, leveraging real-world data from Taiwan and the United States, showed a low and comparable RRD risk among adults who initiated fluoroquinolones or other antibiotics with similar indications. This suggests that the RRD risk should not deter the use of fluoroquinolone when clinically indicated.

The Ageing Foot

Feet suffer significant stress throughout a lifetime and undergo ageing-associated problems due to gradual tissue degeneration affecting the skin, connective tissue, and nerves. Oxygen supply to the tissues may be diminished. The skin gets dry and calluses, ulcers and fungal infections of the skin and nails are not uncommon. Ligaments and tendons degenerate and, without proper prevention, deformities including claw toes, hammer toes, tendonitis, and bursitis may occur. Skeletal toe deformities such as bunions, bony spurs, and hallux valgus may increase discomfort, while stress fractures may have an adverse impact on the patients' quality of life. The ageing foot pathology may add up to common age-related problems, such as crystal deposition arthropathies, diabetes mellitus, peripheral circulatory disorders, and peripheral edema, increasing morbidity. This review summarizes ageing-related feet problems, focusing on prevention and treatment. Foot health has a paramount role in overall wellbeing, therefore prevention, proper foot care, and prompt diagnosis and management of ageing-related changes are vital for maintaining a healthy, active status.

High-Performance Polarization Microscopy Reveals Structural Remodeling in Rat Calcaneal Tendons Cultivated In Vitro

Collagenous tissues exhibit anisotropic optical properties such as birefringence and linear dichroism (LD) as a result of their structurally oriented supraorganization from the nanometer level to the collagen bundle scale. Changes in macromolecular order and in aggregational states can be evaluated in tendon collagen bundles using polarization microscopy. Because there are no reports on the status of the macromolecular organization in tendon explants, the objective of this work was to evaluate the birefringence and LD characteristics of collagen bundles in rat calcaneal tendons cultivated in vitro on substrates that differ in their mechanical stiffness (plastic vs. glass) while accompanying the expected occurrence of cell migration from these structures. Tendon explants from adult male Wistar rats were cultivated for 8 and 12 days on borosilicate glass coverslips (n = 3) and on nonpyrogenic polystyrene plastic dishes (n = 4) and were compared with tendons not cultivated in vitro (n = 3). Birefringence was investigated in unstained tendon sections using high-performance polarization microscopy and image analysis. LD was studied under polarized light in tendon sections stained with the dichroic dyes Ponceau SS and toluidine blue at pH 4.0 to evaluate the orientation of proteins and acid glycosaminoglycans (GAG) macromolecules, respectively. Structural remodeling characterized by the reduction in the macromolecular orientation, aggregation and alignment of collagen bundles, based on decreased average gray values concerned with birefringence intensity, LD and morphological changes, was detected especially in the tendon explants cultivated on the plastic substrate. These changes may have facilitated cell migration from the lateral regions of the explants to the substrates, an event that was observed earlier and more intensely upon tissue cultivation on the plastic substrate. The axial alignment of the migrating cells relative to the explant, which occurred with increased cultivation times, may be due to the mechanosensitive nature of the tenocytes. Collagen fibers possibly played a role as a signal source to cells, a hypothesis that requires further investigation, including studies on the dynamics of cell membrane receptors and cytoskeletal organization, and collagen shearing electrical properties.

Research advances in drug therapy for abdominal aortic aneurysms over the past five years: An updated narrative review

BACKGROUND

Abdominal aortic aneurysms (AAA) rupture can lead to patient death. Surgical treatment is currently the optimal treatment for AAA with large diameter (≥50 mm). For AAA with small diameter (30-50 mm), how to administer effective pharmacological treatment to reduce aneurysm expansion rate and rupture risk is the current focus in the field of vascular surgery. There is still no effective drug for the treatment of asymptomatic AAA.

METHODS

This article searches the PubMed, Web of Science, Embase, and Cochrane databases for clinical studies on the drug treatment of abdominal aortic aneurysms in the past 5 years. The latest progress in the drug treatment of AAA was reviewed, including antibiotics, antihypertensive drugs, antiplatelet drugs, hypoglycemic drugs, hypolipidemic drugs, mast cell inhibitors and corticosteroids.

RESULTS

25 studies were included in this narrative review. Among them, metformin revealed therapeutic effect in 2 prospective cohort study and 3 retrospective cohort study. The therapeutic effect of statins was controversial in 3 retrospective cohort study. However, the definite therapeutic effects of antihypertensive agents, antibiotics, mast cell inhibitors, antiplatelet agents and corticosteroids on abdominal aortic aneurysms have not been verified in prospective studies.

CONCLUSION

Metformin provided a positive effect in reducing expansion rate, rupture risk, and perioperative mortality. The therapeutic effect of statins was controversial, which warrant further validation in prospective cohorts. However, there is still a lack of effective agents for the treatment of AAA based on recent studies.

Ciprofloxacin exacerbates dysfunction of smooth muscle cells in a microphysiological model of thoracic aortic aneurysm

Ciprofloxacin use may be associated with adverse aortic events. However, the mechanism underlying the effect of ciprofloxacin on the progression of thoracic aortic aneurysm (TAA) is not well understood. Using an in vitro microphysiological model, we treated human aortic smooth muscle cells (HASMCs) derived from patients with bicuspid aortic valve- or tricuspid aortic valve-associated (BAV- or TAV-associated) TAAs with ciprofloxacin. TAA C57BL/6 mouse models were utilized to verify the effects of ciprofloxacin exposure. In the microphysiological model, real-time PCR, Western blotting, and RNA sequencing showed that ciprofloxacin exposure was associated with a downregulated contractile phenotype, an upregulated inflammatory reaction, and extracellular matrix (ECM) degradation in the normal HASMCs derived from the nondiseased aorta. Ciprofloxacin induced mitochondrial dysfunction in the HASMCs and further increased apoptosis by activating the ERK1/2 and P38 mitogen-activated protein kinase pathways. These adverse effects appeared to be more severe in the HASMCs derived from BAV- and TAV-associated TAAs than in the normal HASMCs when the ciprofloxacin concentration exceeded 100 μg/mL. In the aortic walls of the TAA-induced mice, ECM degradation and apoptosis were aggravated after ciprofloxacin exposure. Therefore, ciprofloxacin should be used with caution in patients with BAV- or TAV-associated TAAs.

Phenotype stability, expansion potential, and senescence of embryonic tendon cells in vitro

Embryonic tendon cells have been studied in vitro to better understand mechanisms of tendon development. Outcomes of in vitro cell culture studies are easily affected by phenotype instability of embryonic tendon cells during expansion in vitro to achieve desired cell numbers, yet this has not been characterized. In the present study, we characterized phenotype stability, expansion potential, and onset of senescence in chick embryo tendon cells from low to high cell doublings. We focused on cells of Hamburger-Hamilton stages (HH) 40 and HH42, where HH40 is the earliest stage associated with substantial increases in extracellular matrix and mechanical properties during embryonic tendon development. HH40 and HH42 cells both downregulated expression levels of tendon phenotype markers, scleraxis and tenomodulin, and exhibited onset of senescence, based on p16 and p21 expression levels, cell surface area, and percentage of β-galactosidase positive cells, before significant decreases in proliferation rates were detected. These findings showed that embryonic tendon cells destabilize phenotype and become senescent earlier than they begin to decline in proliferation rates in vitro. Additionally, embryonic stage of isolation appears to have no effect on proliferation rates, whereas later stage HH42 cells downregulate phenotype and become susceptible to senescence sooner than earlier stage HH40 cells. Based on our data, we recommend chick embryo tendon cells be used before a maximum cumulative doubling level of 12 (passage 4 in this study) to avoid phenotype destabilization and onset of senescence.

Does oral ciprofloxacin affect the structure of thoracic aorta in adult and senile male albino rats? A clue to fluoroquinolones-induced risk of aortic dissection

In this study, the effect of oral ciprofloxacin on the structure of the thoracic aorta in rats was investigated. Twenty four male albino rats were divided into 4 groups (6 rats/group): group I (adult control), group II (adult rats treated with ciprofloxacin), group III (senile control), and group IV (senile rats treated with ciprofloxacin). Rats in groups II and IV received ciprofloxacin via oral gavage in a daily dose of 3.5 mg/kg/d for 14 days, while control rats received equivalent amount of distilled water used to dissolve the drug. After 2 weeks, all rats were sacrificed, thoracic aortae were dissected, and half of the specimens were processed for paraffin sections and examined by light microscopy. The other half of the specimens were prepared for scanning electron microscopy. Sections from rats treated with ciprofloxacin showed evident damaging effect on aortic wall particularly in (group IV). Aortic intima showed, focal desquamation of the lining epithelium. Tunica media exhibited loss of the normal concentric arrangement and degeneration of the smooth muscle cells. Immune staining for alpha smooth muscle actin showed muscle damage. Interestingly, some sections in (group IV) showed out-pouch (aneurysm like) of the aortic wall. There was dense collagen fibers deposition. Scanning electron microscopic observations of (group IV) revealed uneven intima, adherent blood cells and fibrin filaments to damaged intima, and out-pouch formation. It was concluded that oral ciprofloxacin caused deleterious structural changes in the thoracic aortic wall of rats explaining clinical observations of fluoroquinolones induced risk of aortic dissection and aneurysm.

Species variations in tenocytes' response to inflammation require careful selection of animal models for tendon research

For research on tendon injury, many different animal models are utilized; however, the extent to which these species simulate the clinical condition and disease pathophysiology has not yet been critically evaluated. Considering the importance of inflammation in tendon disease, this study compared the cellular and molecular features of inflammation in tenocytes of humans and four common model species (mouse, rat, sheep, and horse). While mouse and rat tenocytes most closely equalled human tenocytes’ low proliferation capacity and the negligible effect of inflammation on proliferation, the wound closure speed of humans was best approximated by rats and horses. The overall gene expression of human tenocytes was most similar to mice under healthy, to horses under transient and to sheep under constant inflammatory conditions. Humans were best matched by mice and horses in their tendon marker and collagen expression, by horses in extracellular matrix remodelling genes, and by rats in inflammatory mediators. As no single animal model perfectly replicates the clinical condition and sufficiently emulates human tenocytes, fit-for-purpose selection of the model species for each specific research question and combination of data from multiple species will be essential to optimize translational predictive validity.

The association between fluoroquinolones and aortic dissection and aortic aneurysms: a systematic review and meta-analysis

Previous studies have drawn causal associations between fluoroquinolone use and collagen pathologies including tendon rupture and retinopathy. This meta-analysisattempted to assess the association between fluoroquinolone use and the risk of aortic dissection or aortic aneurysm. A systematic search was performed on Medline, EMBASE, and the Cochrane library. 9 studies were included in final analysis. Primary random-effects meta-analysis of 7 studies, excluding 2 pharmacovigilance studies demonstrated statistically increased odds of aortic dissection (OR, 2.38; 95% CI, 1.71-3.32) aortic aneurysm (OR, 1.98; 95% CI, 1.59-2.48), and aortic aneurysm or dissection (OR, 1.47; 95% CI, 1.13-1.89; I² = 72%) with current use of fluoroquinolones compared to their nonuser counterparts. Based on the "number needed-to-harm" analysis, 7246 (95% CI: 4329 to 14,085) patients would need to be treated with fluoroquinolones for a duration of at least three days in order for one additional patient to be harmed, assuming a population baseline incidence of aortic dissection and aneurysm rupture to be 10 per 100,000 patient-years. With strong statistical association, these findings suggest a causal relationship, warranting future research to elucidate the pathophysiological and mechanistic plausibility of this association. These findings however, should not cease prescription of fluoroquinolones, especially when clinically indicated.

Short-term ciprofloxacin prophylaxis for prostate biopsy and risk of aortic aneurysm. Nationwide, population-based cohort study

INTRODUCTION

The use of quinolones has recently been questioned due to reports on side effects including an increased risk of aortic aneurysm. The aim of the study was to examine the risk of aortic aneurysm (AA) after short-term ciprofloxacin as prophylaxis for prostate biopsy.

MATERIALS AND METHODS

We used the Prostate Cancer data Base Sweden and investigated 192,024 prostate biopsy exposures vs. 554,974 non-exposures for risk of AA.Prostate biopsy was used as a proxy for quinolone use as short-term ciprofloxacin is the recommended and documented prophylaxis in Sweden for this procedure.The outcome was the hazard ratio (HR) of AA in men who underwent a biopsy vs. those that did not.

RESULTS

The absolute risk of AA was small, 39/10,000 person years for all AÁs and for ruptured AÁs 3.5/10,000 person years. In multivariate analyses, there were small, non-significant increases in risk of all AA's (adjusted HR = 1.13, 95% CI: 0.91 to 1.39) and ruptured AÁs (adjusted HR = 1.05, 95% CI: 0.52 to 2.15) in men who underwent biopsy. A significantly increased risk of AA was observed in men diagnosed with high-risk prostate cancer on biopsy (HR = 1.50, 95% CI: 1.15-2.21). The use of prostate biopsy as a proxy for exposure to ciprofloxacin was a limitation of the study.

CONCLUSIONS

Short-term ciprofloxacin was not associated with an increased risk of aortic aneurysm and the increased risk in men with high-risk prostate cancer was likely due detection bias caused by imaging more commonly performed in these men.

A Porcine Organ-Culture Glaucoma Model Mimicking Trabecular Meshwork Damage Using Oxidative Stress

Purpose

Re-cellularization of the trabecular meshwork (TM) using stem cells is a potential novel treatment for ocular hypertension associated with glaucoma. To assess the therapeutic efficacy of this approach, improved in vivo and ex vivo models of TM pathophysiology are needed. Here, we investigate whether oxidative stress, induced by hydrogen peroxide (H2O2), can model glaucomatous ocular hypertension in the readily available porcine anterior segment organ culture model.

Methods

The impact of H2O2 on TM cell viability and function was first evaluated in vitro using primary porcine TM cells. Oxidative stress was then induced by H2O2 infusion into perfused porcine anterior segments. Trabecular meshwork function was assessed by tracking matrix metalloproteinase (MMP) activity and the ability of the preparation to maintain intraocular pressure (IOP) homeostasis after a flow challenge (doubled fluid infusion rate). Finally, the TM was evaluated histologically.

Results

H2O2 treatment resulted in a titratable reduction in cellularity across multiple primary TM cell donor strains. In organ culture preparations, H2O2-treated eyes showed impaired IOP homeostasis (i.e., IOPs stabilized at higher levels after a flow challenge vs. control eyes). This result was consistent with reduced MMP activity and TM cellularity; however, damage to the TM microstructure was not histologically evident in anterior segments receiving H2O2.

Conclusions

Titrated H2O2 infusion resulted in TM cellular dysfunction without destruction of TM structure. Thus, this porcine organ culture model offers a useful platform for assessing trabecular meshwork therapies to treat ocular hypertension associated with glaucoma.

Late Passage Cultivation Induces Aged Astrocyte Phenotypes in Rat Primary Cultured Cells

Astrocytes play various important roles such as maintaining brain homeostasis, supporting neurons, and secreting inflammatory mediators to protect the brain cells. In aged subjects, astrocytes show diversely changed phenotypes and dysfunctions. But, the study of aged astrocytes or astrocytes from aged subjects is not yet sufficient to provide a comprehensive understanding of their important processes in the regulation of brain function. In this study, we induced an in vitro aged astrocyte model through late passage cultivation of rat primary cultured astrocytes. Astrocytes were cultured until passage 7 (P7) as late passage astrocytes and compared with passage 1 (P1) astrocytes as early passage astrocytes to confirm the differences in phenotypes and the effects of serial passage. In this study, we confirmed the morphological, molecular, and functional changes of late passage astrocytes showing aging phenotypes through SA-β-gal staining and measurement of nuclear size. We also observed a reduced expression of inflammatory mediators including IL-1β, IL-6, TNFα, iNOS, and COX2, as well as dysregulation of wound-healing, phagocytosis, and mitochondrial functions such as mitochondrial membrane potential and mitochondrial oxygen consumption rate. Culture-conditioned media obtained from P1 astrocytes promoted neurite outgrowth in immature primary cultures of rat cortices, which is significantly reduced when we treated the immature neurons with the culture media obtained from P7 astrocytes. These results suggest that late passage astrocytes show senescent astrocyte phenotypes with functional defects, which makes it a suitable model for the study of the role of astrocyte senescence on the modulation of normal and pathological brain aging.

Effects and Mechanism of Berberine on the Dexamethasone-Induced Injury of Human Tendon Cells

Objective

To investigate the effects of berberine (Berb) on dexamethasone- (Dex-) induced injury of human tendon cells and its potential mechanism.

Methods

CCK-8 assay was used to explore the appropriate concentration of Dex-induced injury of tendon cells and the doses of Berb attenuates Dex cytotoxicity; cell wound healing assay was used to detect the effects (P < 0.05) of Berb and Dex on the migration ability of tendon cells; flow cytometry was used to measure cell apoptosis; DCF DA fluorescent probe was used to measure the ROS activity of cells. Western blotting was used to detect the expression of phenotype related factors including smooth muscle actin α (SMA-α), type I collagen (Col I), col III, apoptosis-related factors, caspase-3, cleaved caspase-3, caspase-9, cleaved caspase-9, and PI3K/AKT.

Results

CCK-8 assay showed that 1-100 μM Dex significantly inhibited the proliferation of tendon cells in a concentration-dependent manner (P < 0.05), where the inhibitory effect of 100 μM Dex was most significant (P < 0.005), and the pretreatment of 150, 200 μM Berb could reverse those inhibitions (all P < 0.05). Compared with the control group, Dex significantly inhibited cell migration (P < 0.05), while Berb pretreatment could enhance cell migration (P < 0.05). Flow cytometry and ROS assay showed that Dex could induce apoptosis and oxidative stress response of tendon cells (all P < 0.05), while Berb could reverse those responses (P < 0.05). Western blot showed that Dex could inhibit the expression of the col I and III as well as α-SMA (all P < 0.05) and enhance the expression of apoptosis-related factors including cleaved caspase-3 and cleaved caspase-9 (all P < 0.05). Besides, Dex could also inhibit the activation of the PI3K/AKT signaling pathway (all P < 0.05), thus affecting cell function, while Berb treatment significantly reversed the expression of those above proteins (all P < 0.05).

Conclusion

Berb attenuated DEX induced reduction of proliferation and migration, oxidative stress, and apoptosis of tendon cells by activating the PI3K/AKT signaling pathway and regulated the expression of phenotype related biomarkers in tendon cells. However, further studies are still needed to clarify the protective effects of Berb in vivo.

Uremic Toxins and Ciprofloxacin Affect Human Tenocytes In Vitro

Tendinopathy is a rare but serious complication of quinolone therapy. Risk factors associated with quinolone-induced tendon disorders include chronic kidney disease accompanied by the accumulation of uremic toxins. Hence, the present study explored the effects of the representative uremic toxins phenylacetic acid (PAA) and quinolinic acid (QA), both alone and in combination with ciprofloxacin (CPX), on human tenocytes in vitro. Tenocytes incubated with uremic toxins +/- CPX were investigated for metabolic activity, vitality, expression of the dominant extracellular tendon matrix (ECM) protein type I collagen, cell-matrix receptor β1-integrin, proinflammatory interleukin (IL)-1β, and the ECM-degrading enzyme matrix metalloproteinase (MMP)-1. CPX, when administered at high concentrations (100 mM), suppressed tenocyte metabolism after 8 h exposure and at therapeutic concentrations after 72 h exposure. PAA reduced tenocyte metabolism only after 72 h exposure to very high doses and when combined with CPX. QA, when administered alone, led to scarcely any cytotoxic effect. Combinations of CPX with PAA or QA did not cause greater cytotoxicity than incubation with CPX alone. Gene expression of the pro-inflammatory cytokine IL-1β was reduced by CPX but up-regulated by PAA and QA. Protein levels of type I collagen decreased in response to high CPX doses, whereas PAA and QA did not affect its synthesis significantly. MMP-1 mRNA levels were increased by CPX. This effect became more pronounced in the form of a synergism following exposure to a combination of CPX and PAA. CPX was more tenotoxic than the uremic toxins PAA and QA, which showed only distinct suppressive effects.

Etoposide Induces Mitochondrial Dysfunction and Cellular Senescence in Primary Cultured Rat Astrocytes

Brain aging is an inevitable process characterized by structural and functional changes and is a major risk factor for neurodegenerative diseases. Most brain aging studies are focused on neurons and less on astrocytes which are the most abundant cells in the brain known to be in charge of various functions including the maintenance of brain physical formation, ion homeostasis, and secretion of various extracellular matrix proteins. Altered mitochondrial dynamics, defective mitophagy or mitochondrial damages are causative factors of mitochondrial dysfunction, which is linked to age-related disorders. Etoposide is an anti-cancer reagent which can induce DNA stress and cellular senescence of cancer cell lines. In this study, we investigated whether etoposide induces senescence and functional alterations in cultured rat astrocytes. Senescence-associated β-galactosidase (SA-β-gal) activity was used as a cellular senescence marker. The results indicated that etoposide-treated astrocytes showed cellular senescence phenotypes including increased SA-β-gal-positive cells number, increased nuclear size and increased senescence-associated secretory phenotypes (SASP) such as IL-6. We also observed a decreased expression of cell cycle markers, including Phospho- Histone H3/Histone H3 and CDK2, and dysregulation of cellular functions based on wound-healing, neuronal protection, and phagocytosis assays. Finally, mitochondrial dysfunction was noted through the determination of mitochondrial membrane potential using tetramethylrhodamine methyl ester (TMRM) and the measurement of mitochondrial oxygen consumption rate (OCR). These data suggest that etoposide can induce cellular senescence and mitochondrial dysfunction in astrocytes which may have implications in brain aging and neurodegenerative conditions.

PARP1 inhibitor (PJ34) improves the function of aging-induced endothelial progenitor cells by preserving intracellular NAD+ levels and increasing SIRT1 activity

Background

Nicotinamide adenine dinucleotide (NAD⁺) is a critical molecule involved in various biological functions. Poly (ADP-ribose) polymerase 1 (PARP1) and sirtuin 1 (SIRT1) affect cellular NAD⁺ levels and play essential roles in regulating metabolism. However, there has been little research on the effects of PARP1 and SIRT1 crosstalk during senescence.

Methods

We isolated endothelial progenitor cells (EPCs) from human umbilical cord blood and treated them with a PARP1 inhibitor (PJ34).

Results

Using a stress-induced premature aging model built by H₂O₂, transfection with adenoviral vectors, and Western blot analysis, we observed that PJ34 treatment preserved intracellular NAD⁺ levels, increased SIRT1 activity, decreased p53 acetylation, and improved the function of stress-induced premature aging EPCs.

Conclusions

Our results suggest that PJ34 improves the function of aging-induced EPCs and may contribute to cellular therapies for atherosclerosis.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0961-7) contains supplementary material, which is available to authorized users.

Fluoroquinolone use and risk of aortic aneurysm and dissection: nationwide cohort study

OBJECTIVE

To investigate whether oral fluoroquinolone use is associated with an increased risk of aortic aneurysm or dissection.

DESIGN

Nationwide historical cohort study using linked register data on patient characteristics, filled prescriptions, and cases of aortic aneurysm or dissection.

SETTING

Sweden, July 2006 to December 2013.

PARTICIPANTS

360 088 treatment episodes of fluoroquinolone use (78%ciprofloxacin) and propensity score matched comparator episodes of amoxicillin use (n=360 088).

MAIN OUTCOME MEASURES

Cox regression was used to estimate hazard ratios for a first diagnosis of aortic aneurysm or dissection, defined as admission to hospital or emergency department for, or death due to, aortic aneurysm or dissection, within 60 days from start of treatment.

RESULTS

Within the 60 day risk period, the rate of aortic aneurysm or dissection was 1.2 cases per 1000 person years among fluoroquinolone users and 0.7 cases per 1000 person years among amoxicillin users. Fluoroquinolone use was associated with an increased risk of aortic aneurysm or dissection (hazard ratio 1.66 (95% confidence interval 1.12 to 2.46)), with an estimated absolute difference of 82 (95% confidence interval 15 to 181) cases of aortic aneurysm or dissection by 60 days per 1 million treatment episodes. In a secondary analysis, the hazard ratio for the association with fluoroquinolone use was 1.90 (1.22 to 2.96) for aortic aneurysm and 0.93 (0.38 to 2.29) for aortic dissection.

CONCLUSIONS

In a propensity score matched cohort, fluoroquinolone use was associated with an increased risk of aortic aneurysm or dissection. This association appeared to be largely driven by aortic aneurysm.

Characteristics of tendon derived stem cells according to different factors to induce the tendinopathy

Tendon derived stem cells (TDSCs) have been used as a therapeutic agent and as a healing marker. However, there has been no study about the characteristics of TDSCs extracted from tendinopathic tendon tissues. The aim of this study was to find the different characteristics of TDSCs according to the factors to induce the tendinopathy. Five- and fifteen-week old Sprague Dawley rats were used for this study and chemically-induced and injury-induced tendinopathy models were made depending on the age of the animal for different types of tendinopathy. TDSCs from chemically-induced tendinopathy showed markedly low proliferation compared to those from age-matched normal control and injury-induced tendinopathy. In addition, TDSCs from chemically-induced tendinopathy progressed to osteogenesis under an osteogenic differentiation environment more than those from other groups. In contrast, TDSCs from injury-induced tendinopathy showed markedly high proliferation and high expression of type III collagen and α-SMA compared to other groups. Adipogenic potentials in TDSCs from injury-induced tendinopathy were also higher. These different characteristics might be helpful in the development new therapeutic agents for tendon regeneration according to different factors to induce the tendinopathy.

Aging does not alter tendon mechanical properties during homeostasis, but does impair flexor tendon healing

Aging is an important factor in disrupted homeostasis of many tissues. While an increased incidence of tendinopathy and tendon rupture are observed with aging, it is unclear whether this is due to progressive changes in tendon cell function and mechanics over time, or an impaired repair reaction from aged tendons in response to insult or injury. In the present study, we examined changes in the mechanical properties of Flexor Digitorum Longus (FDL), Flexor Carpi Ulnaris (FCU), and tail fascicles in both male and female C57Bl/6 mice between 3 and 27 months of age to better understand the effects of sex and age on tendon homeostasis. No change in max load at failure was observed in any group over the course of aging, although there were significant decreases in toe and linear stiffness in female mice from 3 to 15 months, and 3 to 27 months. No changes in cell proliferation were observed with aging, although an observable decrease in cellularity occurred in 31-month old tendons. Given that aging did not dramatically alter tendon mechanical homeostasis we hypothesized that a disruption in tendon homeostasis, via acute injury would result in an impaired healing response. Significant decreases in max load, stiffness, and yield load were observed in repairs of 22-month old mice, relative to 4-month old mice. No changes in cell proliferation were observed between young and aged, however, a dramatic loss of bridging collagen extracellular matrix was observed in aged repairs suggest that matrix production, but not cell proliferation leads to impaired tendon healing with aging. Results © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2716-2724, 2017.

Fluoroquinolones and the Risk of Achilles Tendon Disorders: Update on a Neglected Complication

OBJECTIVE

To evaluate the current evidence and to identify associated risk factors that increase the incidence of this complication. Fluoroquinolone (FQ) has been considered the first-line therapy for uncomplicated urinary infections. FQ has been associated with Achilles tendon disorders, especially during the first month of treatment.

METHODS

Data sources searched included PubMed, MEDLINE, and Scopus from January 1988 to June 2017.

RESULTS

A total of 79 articles were used, with ciprofloxacin representing the most common drug.

CONCLUSION

We found that male gender, advanced age, normal body mass index, chronic renal failure, and concurrent use of corticosteroids increase the risk of Achilles tendon disorders.

Analysis of positions and substituents on genotoxicity of fluoroquinolones with quantitative structure-activity relationship and 3D Pharmacophore model

The genotoxicity values of 21 quinolones were studied to establish a quantitative structure-activity relationship model and 3D Pharmacophore model separately for screening essential positions and substituents that contribute to genotoxicity of fluoroquinolones (FQs). A full factor experimental design was performed to analyze the specific main effect and second-order interaction effect of different positions and substituents on genotoxicity, forming a reasonable modification scheme which was validated on typical FQ with genotoxicity and efficacy data. Four positions (1, 5, 7, 8) were screened finally to form the full factorial experimental design which contained 72 congeners in total, illustrating that: the dominant effect of 5 and 7-positions on genotoxicity of FQs is main effect; meanwhile the effect of 1 and 8-positions is a second-order interaction effect; two adjacent positions always have stronger second-order interaction effect and lower genotoxicity; the obtained modification scheme had been validated on typical FQ congeners with the modified compound has a lower genotoxicity, higher synthesis feasibilities and efficacy.

Spontaneous bilateral patellar tendon rupture: case report and review of fluoroquinolone-induced tendinopathy

The present case emphasizes the importance of adhering to strict indications when prescribing fluoroquinolones. Although rare, drug‐induced tendinopathy is not confined to fluoroquinolones. The patient's and physician's awareness should be increased to reduce fluoroquinolones‐associated morbidity, particularly in patients with previously described risk factors.

Scaffolds and tissue regeneration: An overview of the functional properties of selected organic tissues

Tissue engineering plays a significant role both in the re-establishment of functions and regeneration of organic tissues. Success in manufacturing projects for biological scaffolds, for the purpose of tissue regeneration, is conditioned by the selection of parameters such as the biomaterial, the device architecture, and the specificities of the cells making up the organic tissue to create, in vivo, a microenvironment that preserves and further enhances the proliferation of a specific cell phenotype. To support this approach, we have screened scientific publications that show biomedical applications of scaffolds, biomechanical, morphological, biochemical, and hemodynamic characteristics of the target organic tissues, and the possible interactions between different cell matrices and biological scaffolds. This review article provides an overview on the biomedical application of scaffolds and on the characteristics of the (bio)materials commonly used for manufacturing these biological devices used in tissue engineering, taking into consideration the cellular specificity of the target tissue. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1483-1494, 2016.

Effect of young extrinsic environment stimulated by hypoxia on the function of aged tendon stem cell

Tendon stem cells (TSCs), recently identified as tendon cells, play an important role in maintaining the homeostasis of tendon tissue. Age-related decrease in the function of TSCs has been reported. Recent reports demonstrated that hypoxic condition is advantageous for efficient expansion of TSCs. Moreover, the impaired function of aged stem cells could be modulated by exposing them to a young environment. Therefore, we investigated the effects of hypoxic-conditioned culture medium (HCCM) from young TSCs on the proliferation, migration, senescence, and tenocyte phenotype of aged TSCs. TSCs were isolated, and the conditioned medium was collected. There were 4 groups: young TSCs, aged TSCs, aged TSCs + aged HCCM, and aged TSCs + young HCCM. The proliferative capacity, migration, β-galactosidase activity, and tenogenic differentiation potential of TSCs were assessed. Our results showed that HCCM enhanced the proliferation and migration potential of aged TSCs. Moreover, the senescence-associated β-galactosidase activity of aged TSCs was decreased by young HCCM. After being cultured in the young HCCM, the expressions of tenocyte-related genes in aged TSCs were significantly enhanced. Together, results of this study indicate that HCCM from young TSCs may represent an effective strategy to improve the impaired function of aged TSCs.

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.

Bilateral Achilles Tendon Ruptures Associated With Ciprofloxacin Use in the Setting of Minimal Change Disease: Case Report and Review of the Literature

Fluoroquinolones are widely used antibiotics; however, numerous side effects have been reported in published studies, including a spectrum of tendinopathies, affecting numerous anatomic sites. Several risk factors have been identified, including advanced age (>60 years), corticosteroid use, renal failure or dialysis, female sex, and nonobesity. We present the case of an elderly male with minimal change disease treated with glucocorticoids and acute kidney injury, who sustained spontaneous nontraumatic bilateral Achilles tendon tears 4 days after initiating ciprofloxacin.

An overview of structure, mechanical properties, and treatment for age-related tendinopathy

Tendons transfer tensile loads from muscle to bone, which enable joint motions and stabilize joints. Tendons sustain large mechanical loads in vivo and as a result, tendons were frequently injured. Aging has been confirmed as a predisposing factor of tendinopathy and bad recovery quality following tendon repair. Current treatment methods are generally not effective and involve either symptomatic relief with non-steroidal antiinflammatory drugs and physical therapy or surgery when conservative treatments failed. The limitation in treatment options is due to our incomplete knowledge of age-related tendinopathy. Studies over the past decades have uncovered a number of important mechanical and cellular changes of aging tendon. However, the basis of aging as a major risk factor for tendon injury and impaired tendon healing remained poorly understood. The objectives of this review are to provide an overview of the current knowledge about the aging-associated changes of structure, mechanical properties and treatment in tendon and highlight causes and therapies for age-related tendinopathy.

Extracorporeal Shock Wave Treatment (ESWT) improves in vitro functional activities of ruptured human tendon-derived tenocytes

In vitro models of human tenocytes derived from healthy as well as from ruptured tendons were established, characterized and used at very early passage (P1) to evaluate the effects of Extracorporeal Shock Wave Treatment (ESWT). The molecular analysis of traditional tenocytic markers, including Scleraxis (Scx), Tenomodulin (Tnm), Tenascin-C (Tn-C) and Type I and III Collagens (Col I and Col III), permitted us to detect in our samples the simultaneous expression of all these genes and allowed us to compare their levels of expression in relationship to the source of the cells and treatments. In untreated conditions, higher molecular levels of Scx and Col I in tenocytes from pathological compared to healthy samples have been detected, suggesting – in the cells from injured tendon – the natural trigger of an early differentiation and repairing program, which depends by Scx and requires an increase in collagen expression. When ESWT (at the dose of 0.14 mJ/mm²) was applied to cultured tenocytes explanted from injured source, Scx and Col I were significantly diminished compared to healthy counterpart, indicating that such natural trigger maybe delayed by the treatment, in order to promote cellular repair. Herein, we show for the first time that ESWT enhances in vitro functional activities of ruptured tendon-derived tenocytes, such as proliferation and migration, which could probably contributes to tendon healing in vivo.

A systematic review of the histological and molecular changes in rotator cuff disease

INTRODUCTION

The pathogenesis of rotator cuff disease (RCD) is complex and not fully understood. This systematic review set out to summarise the histological and molecular changes that occur throughout the spectrum of RCD.

METHODS

We conducted a systematic review of the scientific literature with specific inclusion and exclusion criteria.

RESULTS

A total of 101 studies met the inclusion criteria: 92 studies used human subjects exclusively, seven used animal overuse models, and the remaining two studies involved both humans and an animal overuse model. A total of 58 studies analysed supraspinatus tendon exclusively, 16 analysed subacromial bursal tissue exclusively, while the other studies analysed other tissue or varying combinations of tissue types including joint fluid and muscle. The molecular biomarkers that were altered in RCD included matrix substances, growth factors, enzymes and other proteins including certain neuropeptides.

CONCLUSIONS

The pathogenesis of RCD is being slowly unravelled as a result of the significant recent advances in molecular medicine. Future research aimed at further unlocking these key molecular processes will be pivotal in developing new surgical interventions both in terms of the diagnosis and treatment of RCD.