Redox-activity and in vitro effects of regional atmospheric aerosol pollution: Seasonal differences and correlation between oxidative potential and in vitro toxicity of PM1.

Particulate Matter (PM) is a complex and heterogeneous mixture of atmospheric particles recognized as a threat to human health. Oxidative Potential (OP) measurement is a promising and integrative method for estimating PM-induced health impacts since it is recognized as more closely associated with adverse health effects than ordinarily used PM mass concentrations. OP measurements could be introduced in the air quality monitoring, along with the parameters currently evaluated. PM deposition in the lungs induces oxidative stress, inflammation, and DNA damage. The study aimed to compare the OP measurements with toxicological effects on BEAS-2B and THP-1 cells of winter and summer PM1 collected in the Po Valley (Italy) during 2021. PM1 was extracted in deionized water by mechanical agitation and tested for OP and, in parallel, used to treat cells. Cytotoxicity, genotoxicity, oxidative stress, and inflammatory responses were assessed by MTT test, DCFH-DA assay, micronucleus, γ-H2AX, comet assay modified with endonucleases, ELISA, and Real-Time PCR. The evaluation of OP was performed by applying three different assays: dithiothreitol (OPDTT), ascorbic acid (OPAA), and 2',7'-dichlorofluorescein (OPDCFH), in addition, the reducing potential was also analysed (RPDPPH). Seasonal differences were detected in all the parameters investigated. The amount of DNA damage detected with the Comet assay and ROS formation highlights the presence of oxidative damage both in winter and in summer samples, while DNA damage (micronucleus) and genes regulation were mainly detected in winter samples. A positive correlation with OPDCFH (Spearman's analysis, p < 0.05) was detected for IL-8 secretion and γ-H2AX. These results provide a biological support to the implementation in air quality monitoring of OP measurements as a useful proxy to estimate PM-induced cellular toxicological responses. In addition, these results provide new insights for the assessment of the ability of secondary aerosol in the background atmosphere to induce oxidative stress and health effects.

Toxicological Profile of PM from Different Sources in the Bronchial Epithelial Cell Line BEAS-2B.

The toxicity of particulate matter (PM) is strictly associated with its physical-chemical characteristics, such as size or chemical composition. While these properties depend on the origin of the particles, the study of the toxicological profile of PM from single sources has rarely been highlighted. Hence, the focus of this research was to investigate the biological effects of PM from five relevant sources of atmospheric PM: diesel exhaust particles, coke dust, pellet ashes, incinerator ashes, and brake dust. Cytotoxicity, genotoxicity, oxidative, and inflammatory response were assessed in a bronchial cell line (BEAS-2B). BEAS-2B cells were exposed to different concentrations (25, 50, 100, and 150 µg/mL medium) of particles suspended in water. The exposure lasted 24 h for all the assays performed, except for reactive oxygen species, which were evaluated after 30 min, 1 h, and 4 h of treatment. The results showed a different action of the five types of PM. All the tested samples showed a genotoxic action on BEAS-2B, even in the absence of oxidative stress induction. Pellet ashes seemed to be the only ones able to induce oxidative stress by boosting the formation of reactive oxygen species, while brake dust resulted in the most cytotoxic. In conclusion, the study elucidated the differential response of bronchial cells to PM samples generated by different sources. The comparison could be a starting point for a regulatory intervention since it highlighted the toxic potential of each type of PM tested.

New approach methodologies in immunotoxicology: challenges and opportunities.

To maintain the integrity of an organism, a well-functioning immune system is essential. Immunity is dynamic, with constant surveillance needed to determine whether to initiate an immune response or to not respond. Both inappropriate immunostimulation and decreased immune response can be harmful to the host. A reduced immune response can lead to high susceptibility to cancer or infections, whereas an increased immune response can be related to autoimmunity or hypersensitivity reactions. Animal testing has been the gold standard for hazard assessment in immunotoxicity but a lot of efforts are ongoing to develop non-animal-based test systems, and important successes have been achieved. The term "new approach methodologies" (NAMs) refer to the approaches which are not based on animal models. They are applied in hazard and risk assessment of chemicals and include approaches such as defined approaches for data interpretation and integrated approaches to testing and assessment. This review aims to summarize the available NAMs for immunotoxicity assessment, taking into consideration both inappropriate immunostimulation and immunosuppression, including implication for cancer development.

Lack of genotoxicity of rhubarb (rhizome) in the Ames and micronucleus in vitro tests.

Hydroxyanthracene derivatives are widely distributed in the plant kingdom, mainly in botanicals such as the Hypericum, Rheum, Rhamnus and Aloe genera. For centuries, plants containing hydroxyanthracene derivatives have been used as herbal remedies, mainly as laxatives. The root and underground stem (rhizome) are used to make medicine, primarily for digestive complaints including constipation, diarrhoea, heartburn, stomach pain, gastrointestinal bleeding, and preparation for certain gastrointestinal diagnostic procedures. The use of hydroxyanthracene-containing botanicals has raised the attention of European Food Safety Authority (EFSA) for the potential genotoxicity activity, that in 2018 concluded "[.] and that there is a safety concern for extracts containing hydroxyanthracene derivatives although uncertainty persists". No genotoxic activity has been reported with other constituents such as rhein, physcion and chrysophanol. In the present study, Rhubarb ethanolic extract of ground rhubarb rhizome (hydroxyanthracene total content 1.39 %) was tested in the Ames Assay in Salmonella typhimurium and Escherichia coli, up to 5000 µg/plate and up to 5000 µg/mL in human lymphocytes Micronucleus Test (OECD 471 and 487 respectively) in vitro mutagenic and genotoxic effects. Under the experimental conditions used, the rhubarb rhizome extract showed no genotoxic activity.

Keratin 17 as a Marker of UVB-Induced Stress in Human Epidermis and Modulation by Vitis vinifera Extract.

Human epidermis responds to ultraviolet (UV)B-induced damage by tolerating it, restoring it, or undergoing programmed cell death when the damage is massive. Recently, compounds rich in polyphenols, such as Vitis vinifera L. leaf extract (VVLe), have attracted a lot of interest for skin protection. We investigated the effect of VVLe pre-treatment (1 h) in a 2D model of HaCaT cells and in 3D organotypic cultures of normal human skin exposed to a single UVB dose to study the immediate specific events 1 h and the response orchestrated in the epidermal layer 24 h after irradiation, respectively. In both models, transmission electron microscopy analysis was carried out. The expression of the inducible keratin K17, the activation of both pSTAT3 and Nuclear Factor (NF)-κB signalling pathways, and the epidermal distribution of Toll-Like Receptor (TLR) 4 were assessed by immunofluorescence in the 2D and 3D model. In 3D organotypic cultures, thanks to the preservation of a multi-layered structure, the epidermal distribution of the differentiation biomarkers K10 and K14 as well as of K16 was analysed by immunofluorescence, while the release of interleukin (IL)-8 was evaluated by ELISA. In skin bioptic fragments, cytotoxicity and genotoxicity were investigated by LDH assay and Alkaline Comet assay, respectively, and then compared to cell proliferation. The epidermal distribution of the histone γ-H2AX, indicating the fragmented DNA, was analysed by immunofluorescence. In both experimental models, VVLe tuned UVB-induced K17 expression to a different extent in HaCaT cells and in the skin. In HaCaT cells, pSTAT3 activation was induced by UVB and reverted by VVLe pre-treatment. TLR4 expression was triggered by UVB in both models, but VVLe pre-treatment abolished this event only in HaCaT cells. NF-κB immunostaining increased both in the nucleus and in the cytoplasm only in HaCaT cells after UVB irradiation. In all irradiated skin samples, VVLe pre-treatment was not able to revert the inhibition of epidermal proliferation, K16 expression, and IL-8 secretion. The effectiveness of VVLe in contrasting the irradiation-induced genotoxicity still remains unclear. In conclusion, our study clearly shows that K17 is a robust marker induced in keratinocytes upon UVB stimulation and that this event can be reverted by a pre-treatment with VVLe. On the whole, these observations represent a novelty in the scenario of the complex relationships between the effects exerted by UVB rays on human skin and significantly improve the knowledge regarding the modulation of the early epidermal response induced by a single exposure to UVB in the presence of VVLe.

Lack of in vivo genotoxic effect of dried whole Aloe ferox juice.

Aloe ferox Mill is widely used as a traditional herbal medicine for the treatment of a broad spectrum of illnesses given its laxative, anti-inflammatory, bitter tonic, anti-oxidant, antimicrobial and anti-cancer properties. Using the in vivo alkaline comet assay in animals (OECD 489), this study investigated the potential in vivo genotoxicity of dried Aloe ferox juice at dose levels of 500, 1000, and 2000 mg/kg/day in mice. Aloe ferox showed no genotoxic activity in preparations of single cells from the colon of the treated Hsd:ICR (CD-1) male mice. No statistically significant increase in DNA migration over the negative control was observed by analysis of variance for both comet parameters, tail moment and tail intensity, apart from the positive control ethyl methanesulphonate that induced clear and statistically significant increases in DNA migration parameters over the concurrent controls. The new reported scientific evidence unequivocally demonstrates that dried Aloe ferox juice containing hydroxyanthracene derivatives does not induce DNA damage in preparations of single cells from colon in in vivo comet genotoxicity studies. This suggests that the hyperplastic changes and mucosal hyperplasia observed after long-term administration of Aloe vera non-decolourised whole leaf extract may be attributed to an epigenetic effect of the material under investigation.

Aloe-emodin, a hydroxyanthracene derivative, is not genotoxic in an in vivo comet test.

Aloe-emodin, one of the molecules belonging to the group of hydroxyanthracene derivatives, was recently described as genotoxic in vivo. Indeed, the EFSA judged that aloe-emodin, together with other similar molecules (emodin and danthron) and extracts from the leaf of Aloe species containing hydroxyanthracene derivatives, could represent a risk factor for colorectal cancer mediated by a genotoxic effect. Given the marked uncertainty regarding the conclusions in the opinion of the EFSA ANS Panel and conflicts in the epidemiological data on which the opinion is based, a new in vivo study (in vivo alkaline comet assay in mice - OECD 489) was conducted to test the potential genotoxicity of aloe-emodin at doses of 250, 500, 1000 and 2000 mg/kg bw/day on preparations of single cells from the kidney and colon of treated male mice. Following treatment with the test item, no clinical signs were observed in animals in any treatment group. Slight body-weight loss was randomly observed in all groups treated with the test item and was more evident in the groups dosed at 1000 and 2000 mg/kg bw/day. Under these experimental conditions, aloe-emodin showed no genotoxic activity. Possible oxidative damage to colon tissues could not be excluded based on the results obtained after repair enzyme treatment.

Conservation of mechanisms regulating emotional-like responses on spontaneous nicotine withdrawal in zebrafish and mammals.

BACKGROUND: Nicotine withdrawal syndrome is a major clinical problem. Animal models with sufficient predictive validity to support translation of pre-clinical findings to clinical research are lacking. AIMS: We evaluated the behavioural and neurochemical alterations in zebrafish induced by short- and long-term nicotine withdrawal. METHODS: Zebrafish were exposed to 1 mg/L nicotine for 2 weeks. Dependence was determined using behavioural analysis following mecamylamine-induced withdrawal, and brain nicotinic receptor binding studies. Separate groups of nicotine-exposed and control fish were assessed for anxiety-like behaviours, anhedonia and memory deficits following 2-60 days spontaneous withdrawal. Gene expression analysis using whole brain samples from nicotine-treated and control fish was performed at 7 and 60 days after the last drug exposure. Tyrosine hydroxylase (TH) immunoreactivity in pretectum was also analysed. RESULTS: Mecamylamine-precipitated withdrawal nicotine-exposed fish showed increased anxiety-like behaviour as evidenced by increased freezing and decreased exploration. 3H-Epibatidine labeled heteromeric nicotinic acethylcholine receptors (nAChR) significantly increased after 2 weeks of nicotine exposure while 125I-αBungarotoxin labeled homomeric nAChR remained unchanged. Spontaneous nicotine withdrawal elicited anxiety-like behaviour (increased bottom dwelling), reduced motivation in terms of no preference for the enriched side in a place preference test starting from Day 7 after withdrawal and a progressive decrease of memory attention (lowering discrimination index). Behavioural differences were associated with brain gene expression changes: nicotine withdrawn animals showed decreased expression of chrna 4 and chrna7 after 60 days, and of htr2a from 7 to 60 days.The expression of c-Fos was significantly increased at 7 days. Finally, Tyrosine hydroxylase (TH) immunoreactivity increased in dorsal parvocellular pretectal nucleus, but not in periventricular nucleus of posterior tuberculum nor in optic tectum, at 60 days after withdrawal. CONCLUSIONS: Our findings show that nicotine withdrawal induced anxiety-like behaviour, cognitive alterations, gene expression changes and increase in pretectal TH expression, similar to those observed in humans and rodent models.

Rhus coriaria L. Fruit Extract Prevents UV-A-Induced Genotoxicity and Oxidative Injury in Human Microvascular Endothelial Cells.

Rhus coriaria L. (sumac) is a small plant widely diffused in the Mediterranean region. Its fruit are often consumed as a spice but are also present in traditional medicine of several countries. Recently, interest in this plant has increased and many scientific works reported its beneficial effects including antioxidant and anti-inflammatory properties. Plant extracts can be successfully used against ultraviolet rays, which are able to reach and damage the human skin; however, sumac extracts were never applied to this usage. Thus, in this study, we used a macerated ethanol extract of Rhus coriaria L. dried fruit (mERC) to demonstrate its preventive role against the damage induced by ultraviolet-A rays (UV-A) on microvascular endothelial cells (HMEC-1). In vitro effects of the extract pre-treatment and UV-A exposure were evaluated in detail. The antioxidant capacity was assessed by reactive oxygen species (ROS) formation and cellular antioxidant activity measurement. Genoprotective effects of mERC were investigated as well. Our findings indicate that the extract acts as a cell cycle inhibitor or apoptosis inducer, according to the level of damage. The present work provides new insights into the usage of Rhus coriaria extracts against skin injuries.

Effects of Vitis vinifera L. leaves extract on UV radiation damage in human keratinocytes (HaCaT).

Vitis vinifera L. water extract from red grapevine leaves contains high levels of polyphenols in quantities similar to those found in red grape and grape seeds. Phenolic compounds are the largest group of natural antioxidants with also an anti-inflammatory activity, widely demonstrated both in vitro and in vivo. Interestingly, their antioxidant effect relies not only on the direct radical scavenging activity but also on their ability in modulating cellular signalling transduction pathways. UV radiation exerts multiple effects on skin cells inducing apoptosis, senescence and carcinogenesis. The aim of this study was to investigate the antioxidant and the DNA protective potentials of Vitis vinifera L. water extract against UV-A and UV-B radiation in HaCaT cells, a human keratinocytes cell line. Comet and É£H2AX assays were used to assess DNA damage in UV irradiated cells pre-treated or not with the extract (100 µg/mL). For UV-B, DNA damage resulted significantly increased at 40 mJ/cm2 dose determining cell cycle arrest and apoptosis. For UV-A, DNA damage was significant at 10 J/cm2 while cell cycle arrest and apoptosis were evident only at 25 J/cm2. The extract (1h of pre-treatment) highlights the antioxidant and scavenger activity on the UV-A, while the maintenance of the apoptosis with both UV-A and UV-B must be interpreted as an anti-mutagenic effect.

Cannabis sativa L. extract and cannabidiol inhibit in vitro mediators of skin inflammation and wound injury.

Skin inflammatory diseases result from complex events that include dysregulation and abnormal expression of inflammatory mediators or their receptors in skin cells. The present study investigates the potential effect of a Cannabis sativa L. ethanolic extract standardized in cannabidiol as antiinflammatory agent in the skin, unraveling the molecular mechanisms in human keratinocytes and fibroblasts. The extract inhibited the release of mediators of inflammation involved in wound healing and inflammatory processes occurring in the skin. The mode of action involved the impairment of the nuclear factor-kappa B (NF-κB) pathway since the extract counteracted the tumor necrosis factor-alpha-induced NF-κB-driven transcription in both skin cell lines. Cannabis extract and cannabidiol showed different effects on the release of interleukin-8 and vascular endothelial growth factor, which are both mediators whose genes are dependent on NF-κB. The effect of cannabidiol on the NF-κB pathway and metalloproteinase-9 (MMP-9) release paralleled the effect of the extract thus making cannabidiol the major contributor to the effect observed. Down-regulation of genes involved in wound healing and skin inflammation was at least in part due to the presence of cannabidiol. Our findings provide new insights into the potential effect of Cannabis extracts against inflammation-based skin diseases.

Vitis vinifera L. Leaf Extract Inhibits In Vitro Mediators of Inflammation and Oxidative Stress Involved in Inflammatory-Based Skin Diseases.

Psoriasis is a chronic cutaneous condition characterized by the release of pro-inflammatory mediators and oxidative stress. The reduction of these factors is currently the most effective strategy to inhibit the symptoms of pathology. Antioxidants from natural sources are increasingly used to improve skin conditions. Dried red leaves from grapevine (Vitis vinifera L., cv Teinturiers) showed anti-inflammatory and anti-bacterial activities, but their possible effects on keratinocytes have not been previously investigated. In this study we tested the ability of a water extract from grapevine leaves (VVWE) to inhibit inflammatory conditions in human keratinocytes (HaCaT cells), challenged with proinflammatory (tumor necrosis factor-α (TNF-α) or lipopolysaccharide (LPS)) or prooxidant (ultraviolet B radiation (UVB) or H2O2) mediators. VVWE inhibited interleukin-8 (IL-8) secretion induced by proinflammatory stimuli, acting on the IL-8 promoter activity, but the effect was lower when prooxidant mediators were used. The effect was partly explained by the reduction of nuclear factor-κB (NF-κB)-driven transcription and nuclear translocation. Furthermore, vascular endothelial growth factor (VEGF) secretion, a regulator of angiogenesis, was inhibited by VVWE, but not matrix metalloproteinase-9 (MMP-9), a protease involved in matrix remodeling. VVWE, assayed on Franz diffusion cell system, showed a marked reduction of High Performance Liquid Chromatography (HPLC)-identified compounds. Pure molecules individually failed to reduce TNF-α-induced IL-8 release, suggesting synergistic effects or the presence of other bioactive compounds still unknown.

Incidence and predictors of drug-eluting stent thrombosis during and after discontinuation of thienopyridine treatment.

BACKGROUND: The need for prolonged aspirin and thienopyridine therapy and the risk of stent thrombosis (ST) remain as drawbacks associated with drug-eluting stents. METHODS AND RESULTS: A prospective observational cohort study was conducted between June 2002 and January 2004 on 3021 patients consecutively and successfully treated in 5389 lesions with drug-eluting stents. Detailed patient information was collected on antiplatelet therapy. We analyzed the incidence of ST throughout the 18-month follow-up period and its relationship with thienopyridine therapy. ST occurred in 58 patients (1.9%) at 18 months. Forty-two patients (1.4%) experienced the event within 6 months of stent implantation. Acute myocardial infarction (fatal or nonfatal) occurred in 46 patients (79%) and death in 23 patients (39%) with ST. The median interval from discontinuation of thienopyridine therapy to ST was 13.5 days (interquartile range 5.2 to 25.7 days) for the first 6 months and 90 days (interquartile range 30 to 365 days) between 6 and 18 months. On multivariable analysis, the strongest predictor for ST within 6 months of stenting was discontinuation of thienopyridine therapy (hazard ratio, 13.74; 95% CI, 4.04 to 46.68; P<0.001). Thienopyridine discontinuation after 6 months did not predict the occurrence of ST (hazard ratio, 0.94; 95% CI, 0.30 to 2.98; P=0.92). CONCLUSIONS: Discontinuation of thienopyridine therapy was the major determinant of ST within the first 6 months, but insufficient information is available to determine whether there is benefit in continuing a thienopyridine beyond 6 months.

Comparable clinical outcomes with paclitaxel- and sirolimus-eluting stents in unrestricted contemporary practice.

OBJECTIVES: This study was designed to compare the outcomes of paclitaxel-eluting stents (PES) and sirolimus-eluting stents (SES) in a contemporaneous cohort of real-world patients. BACKGROUND: A number of randomized comparisons of PES and SES have shown unequivocal advantages for SES in angiographic end points such as late loss. However, the data on clinical outcomes are less consistent. METHODS: All consecutive patients successfully treated with only SES or PES in de novo native vessel lesions between March 2003 and March 2005 were analyzed. Our end points were major adverse cardiac events (MACE), a composite of death, myocardial infarction (MI), target vessel revascularization (TVR), and target lesion revascularization (TLR). We also analyzed late loss and angiographic restenosis. RESULTS: There were 609 patients (1,064 lesions) treated with PES and 674 patients (1,205 lesions) treated with SES. Diabetes mellitus was present in 26.8% of patients and multivessel disease in 75% of patients. Bifurcations made up 16.3% of lesions, chronic occlusions 9.5%, left main 4.8%, and American Heart Association/American College of Cardiology type B2/C 75.4%. Despite a higher late loss in the PES group (p = 0.0001), there were no differences in angiographic restenosis (PES 18% vs. SES 17.8%, p = 0.95), TLR (PES 11.9% vs. SES 11%, p = 0.47), or MACE (PES 21.3% vs. SES 21.1%, p = 0.95). The relative risk of MACE for the PES group was 1.02 (95% confidence interval [CI] 0.78 to 1.33). Multivariable analysis confirmed the lack of association of stent type with MACE (odds ratio 1.03 [95% CI 0.77 to 1.38], p = 0.83) and TLR (odds ratio 1.08 [95% CI 0.81 to 1.44], p = 0.61). CONCLUSIONS: In this complex cohort, both stent platforms demonstrated similar clinical outcomes despite different late loss.

Late restenosis following sirolimus-eluting stent implantation.

Despite encouraging results from randomized trials, concerns exist about long-term results of sirolimus-eluting stent implantation. We sought to determine whether in-stent restenosis occurring >1 year ("late") after sirolimus-eluting stent implantation is a real clinical entity. We analyzed data on all sirolimus-eluting stents implanted in our institution before March 2003. During the study period 928 lesions in 433 patients were treated. Angiographic follow-up was performed in 306 patients (70.6%) with 679 lesions (73.2%). Angiography after 1 year was performed only in symptomatic patients. We considered restenosis "early" if it occurred during the first year and late if after 1 year. Late restenosis required demonstration of a widely patent stent at 6 to 9 months, with repeat angiography after 1 year demonstrating restenosis. Restenosis occurred in 160 lesions overall (23.5%). Of the 31 (4.6%) that were documented after 1 year, 13 were excluded from analysis due to absence of 6- to 9-month angiography; the remaining 18 (2.6%, 1.7 to 4.2) fulfilled our criteria for late restenosis (median time of documentation 607 days, interquartile range 511 to 923). In conclusion, late restenosis is an infrequent but real entity; its existence implies we should not discount the possibility of restenosis as the cause of symptoms that develop >1 year after sirolimus-eluting stent implantation.

Engineering aspects of stents design and their translation into clinical practice.

The implantation of coronary stents is a relevant part of interventional procedures for percutaneous revascularization. The wide acceptance of coronary stenting was based on the results of two highly significant trials which have shown the superiority of stenting over balloon angioplasty in terms of reduction of angiographic restenosis and need for repeated intervention in focal lesions and large coronary arteries. Since then, the growing use of stent market was impressive. A rapidly increasing number of different stent type with different material and designs has been introduced in the market both for bare metal stent and drug eluting stent. This review will summarize the different components of stent design that are important in term of biological response of the arterial wall and clinical outcome. In addition, new stent platforms, mainly represented by the biodegradable stent will be shortly reviewed since it may provide in the near future a more "physiological" answer to stent implantation, reducing vascular injury and accelerating vessel healing with consequent improving in clinical outcome.

Repeated drug-eluting stent implantation for drug-eluting stent restenosis: the same or a different stent.

BACKGROUND: Currently, little data are available on the management of drug-eluting stent (DES) restenosis. Drug resistance may play a role in its etiology. METHODS: We identified all cases of either sirolimus-eluting or paclitaxel-eluting stent restenosis treated with repeated DES implantation. The lesions were divided into those receiving the same DES as the one that restenosed and those treated with the alternative DES. The end points analyzed were target lesion revascularization (TLR) and angiographic restenosis. RESULTS: We included 201 lesions (174 patients); the same DES was implanted in 107 lesions and a different DES in 94 lesions. Angiographic follow-up of the retreatment was available in 69.7% of the lesions. Angiographic restenosis occurred in 26.4% (19) of cases treated with the same DES and 25.8% (17) of those treated with a different DES (P = 1.0). Target lesion revascularization occurred in 15.9% (17) and 16% (15) of lesions, respectively (P = 1.0). A multivariate analysis confirmed the lack of association between the treatment selected and TLR (OR 0.7, 95% CIs [0.29-1.67]; P = .42). A nonfocal pattern of restenosis remained associated with TLR and restenosis (OR 2.99, 95% CIs [1.24-7.24]; P = .015 and OR 3.6, 95% CIs [1.5-8.8]; P = .004, respectively). CONCLUSIONS: Repeated DES implantation for DES restenosis is feasible and safe. The TLR rate is acceptable, with no differences between implantation of the same or a different DES. The pattern of restenosis treated is an important predictor of outcomes.

Angiographic analysis of pattern of late luminal loss in sirolimus- and paclitaxel-eluting stents.

Late loss is becoming an important end point to compare drug-eluting stents; however, little is known about its pattern of distribution. We analyzed the pattern of late loss distribution in sirolimus-eluting stents (SESs) and paclitaxel-eluting stents (PESs) in a consecutive cohort of patients. From a cohort of 529 patients treated with drug-eluting stents in 1 year, we selected all patients who underwent angiographic follow-up. Three hundred fifty-nine patients with 592 de novo lesions received SESs (286 lesions) or PESs (306 lesions). Late loss and binary angiographic restenosis were analyzed. Binary restenosis occurred in 56 lesions (19.6%) treated with SESs compared with 53 (17.3%) treated with PESs (p = 0.48). The 2 late loss distributions were skewed to the right and were not normally distributed (p <0.001 for SES, p = 0.003 for PES). Late loss was significantly lower in the SES group (p = 0.03), with a median value of 0.29 mm (interquartile range -0.09 to 0.66) versus 0.41 mm (-0.02 to 0.85) in the PES group. When analyzing only restenotic lesions, late loss had a normal distribution in the SES and PES groups (p = 0.96 and 0.44, respectively) and was similar in the 2 groups (1.75 +/- 0.51 vs 1.82 +/- 0.62, p = 0.48). When evaluating nonrestenotic lesions, late loss was also normally distributed in the 2 groups (p = 0.75 for SES, p = 0.73 for PES) but was significantly lower (p = 0.002) after SES implantation (0.14 +/- 0.39) than after PES implantation (0.27 +/- 0.44). In conclusion, SESs and PESs have a bimodal pattern of late loss distribution. The observed difference in late loss between SES and PES seems to be partly explained by the decrease in late loss after SES implantation in nonrestenotic lesions (where SES approaches "zero late loss"). Thus, late loss may not be a reliable marker of the true efficacy of these devices due to its complex and nongaussian distribution.

Patterns of restenosis after drug-eluting stent implantation: Insights from a contemporary and comparative analysis of sirolimus- and paclitaxel-eluting stents.

AIM: To evaluate patterns of restenosis following implantation of sirolimus-eluting stent (SES) and paclitaxel-eluting stent (PES) in comparable unselected lesions. METHODS AND RESULTS: We have identified all episodes of restenosis after SES or PES implantation in our institutions between March 2003 and March 2005. Restenosis pattern was classified as focal, diffuse, proliferative, or occlusive. The position of focal restenosis was also categorized as proximal, in-stent, distal, or multi-focal. We have characterized 150 and 149 restenotic lesions in SES and PES groups, respectively. The incidence of diffuse and occlusive restenosis was significantly higher in PES than in SES (47.6 vs. 27.0%, P < 0.001). Multivariable (OR 2.693, 95% CI 1.425-5.089, P = 0.002) and propensity (OR 3.00, 95% CI 1.584-5.672, P < 0.001) analyses confirmed the positive association of PES with non-focal restenosis. For both stents, focal-edge restenosis was significantly more likely to occur proximally than distally (61.0 vs. 16.9%, P < 0.001 for PES and 45.8 vs. 16.8%, P < 0.001 for SES). CONCLUSION: Focal restenosis remains the most common pattern with SES. In contrast, just under half of restenosis in PES is the more severe non-focal pattern. Paradoxically, the majority of focal restenosis occurs at the proximal stent margin for both platforms.