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1.
Artículo en Inglés | MEDLINE | ID: mdl-38552315

RESUMEN

OBJECTIVE: To investigate the safety and efficacy of subcutaneous tocilizumab (SC-TCZ) treatment in a long-term extension (LTE) of clinical trials in polyarticular or systemic juvenile idiopathic arthritis (pJIA, sJIA). METHODS: Patients with pJIA or sJIA from two open-label, 52-week phase 1 b core trials of SC-TCZ who had adequate response per investigator assessment entered the LTE and continued SC-TCZ treatment according to body weight-based dosing regimens until commercial availability or up to 5 years. Pharmacokinetics, pharmacodynamics, and efficacy were assessed for up to 3 years and safety for up to 5 years in the LTE. RESULTS: Forty-four patients with pJIA and 38 patients with sJIA entered the LTE. Tocilizumab trough concentrations were maintained within the range expected to provide clinical benefit (mean values: pJIA, ∼10 µg/ml; sJIA, ∼75 µg/ml over 3 years). Pharmacodynamic parameters (interleukin-6, soluble interleukin-6 receptor, erythrocyte sedimentation rate, C-reactive protein) were maintained throughout the LTE at levels achieved in the core trials. Inactive disease per American College of Rheumatology provisional criteria was reported for 90% (17/19) and 53% (8/15) of patients with pJIA and 91% (10/11) and 92% (12/13) of patients with sJIA in the <30 kg and ≥30 kg body weight groups, respectively. Serious adverse events in the LTE were reported in six patients with pJIA (13.6%; five serious infections) and five patients with sJIA (13.2%; one serious infection). CONCLUSION: Patients with pJIA or sJIA experienced long-term disease control with SC-TCZ treatment. Long-term safety was consistent with the known tocilizumab safety profile.

2.
Clin Transl Sci ; 16(6): 1049-1062, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36929625

RESUMEN

Observational studies have identified the potential prognostic value for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral load and anti-SARS-CoV-2 antibodies in coronavirus disease 2019 (COVID-19). However, viral load in nasopharyngeal (NP) swabs produced inconsistent results in prognostic analyses, and the prognostic value of viral load or antibodies has not been confirmed in large clinical trials. COVACTA and REMDACTA were double-blind, randomized, controlled trials with a combined enrollment of 1078 patients hospitalized with COVID-19 treated with tocilizumab or placebo in COVACTA or tocilizumab plus remdesivir or placebo plus remdesivir in REMDACTA. We assessed the potential prognostic value of NP and serum SARS-CoV-2 viral load and serum anti-SARS-CoV-2 antibodies at baseline as biomarkers for clinical outcomes in patients enrolled in these trials. In adjusted Cox proportional hazard models, serum viral load was a more reliable predictor of clinical outcomes than NP viral load; high serum viral load was associated with higher risk for death and mechanical ventilation/death and lower likelihood of hospital discharge (high vs. negative viral load hazard ratios [95% confidence interval {CI}] were 2.87 [1.57-5.25], 3.86 [2.23-6.68], and 0.23 [0.14-0.36], respectively, in COVACTA and 8.11 [2.95-22.26], 10.29 [4.5-23.55], and 0.21 [0.15-0.29], respectively, in REMDACTA) and high serum viral load correlated with levels of inflammatory cytokines and lung damage biomarkers. High anti-SARS-CoV-2 spike protein antibody (ACOV2S) levels were associated with higher likelihood of hospital discharge (high vs. below the limit of quantification hazard ratios [95% CI] were 2.55 [1.59-4.08] for COVACTA and 1.54 [1.13-2.09] for REMDACTA). These results support the role of baseline SARS-CoV-2 serum viral load and ACOV2S antibody titers in predicting clinical outcomes for patients hospitalized with COVID-19.


Asunto(s)
COVID-19 , Humanos , SARS-CoV-2 , Pronóstico , Carga Viral , Pulmón , Anticuerpos Antivirales
3.
Intensive Care Med ; 47(11): 1258-1270, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34609549

RESUMEN

PURPOSE: Trials of tocilizumab in patients with severe COVID-19 pneumonia have demonstrated mixed results, and the role of tocilizumab in combination with other treatments is uncertain. Here we evaluated whether tocilizumab plus remdesivir provides greater benefit than remdesivir alone in patients with severe COVID-19 pneumonia. METHODS: This randomized, double-blind, placebo-controlled, multicenter trial included patients hospitalized with severe COVID-19 pneumonia requiring > 6 L/min supplemental oxygen. Patients were randomly assigned (2:1 ratio) to receive tocilizumab 8 mg/kg or placebo intravenously plus ≤ 10 days of remdesivir. The primary outcome was time from randomization to hospital discharge or "ready for discharge" (defined as category 1, assessed by the investigator on a 7-category ordinal scale of clinical status) to day 28. Patients were followed for 60 days. RESULTS: Among 649 enrolled patients, 434 were randomly assigned to tocilizumab plus remdesivir and 215 to placebo plus remdesivir. 566 patients (88.2%) received corticosteroids during the trial to day 28. Median time from randomization to hospital discharge or "ready for discharge" was 14 (95% CI 12-15) days with tocilizumab plus remdesivir and 14 (95% CI 11-16) days with placebo plus remdesivir [log-rank P = 0.74; Cox proportional hazards ratio 0.97 (95% CI 0.78-1.19)]. Serious adverse events occurred in 128 (29.8%) tocilizumab plus remdesivir and 72 (33.8%) placebo plus remdesivir patients; 78 (18.2%) and 42 (19.7%) patients, respectively, died by day 28. CONCLUSIONS: Tocilizumab plus remdesivir did not shorten time to hospital discharge or "ready for discharge" to day 28 compared with placebo plus remdesivir in patients with severe COVID-19 pneumonia.


Asunto(s)
Anticuerpos Monoclonales Humanizados/uso terapéutico , Antimetabolitos/uso terapéutico , Antivirales , Tratamiento Farmacológico de COVID-19 , Adenosina Monofosfato/análogos & derivados , Alanina/análogos & derivados , Antivirales/uso terapéutico , Humanos
4.
Cell ; 184(15): 4016-4031.e22, 2021 07 22.
Artículo en Inglés | MEDLINE | ID: mdl-34081922

RESUMEN

Cross-presentation of antigens from dead tumor cells by type 1 conventional dendritic cells (cDC1s) is thought to underlie priming of anti-cancer CD8+ T cells. cDC1 express high levels of DNGR-1 (a.k.a. CLEC9A), a receptor that binds to F-actin exposed by dead cell debris and promotes cross-presentation of associated antigens. Here, we show that secreted gelsolin (sGSN), an extracellular protein, decreases DNGR-1 binding to F-actin and cross-presentation of dead cell-associated antigens by cDC1s. Mice deficient in sGsn display increased DNGR-1-dependent resistance to transplantable tumors, especially ones expressing neoantigens associated with the actin cytoskeleton, and exhibit greater responsiveness to cancer immunotherapy. In human cancers, lower levels of intratumoral sGSN transcripts, as well as presence of mutations in proteins associated with the actin cytoskeleton, are associated with signatures of anti-cancer immunity and increased patient survival. Our results reveal a natural barrier to cross-presentation of cancer antigens that dampens anti-tumor CD8+ T cell responses.


Asunto(s)
Reactividad Cruzada/inmunología , Gelsolina/metabolismo , Inmunidad , Lectinas Tipo C/metabolismo , Neoplasias/inmunología , Receptores Inmunológicos/metabolismo , Receptores Mitogénicos/metabolismo , Actinas/metabolismo , Secuencia de Aminoácidos , Animales , Antígenos de Neoplasias/metabolismo , Linfocitos T CD8-positivos/efectos de los fármacos , Linfocitos T CD8-positivos/inmunología , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Reactividad Cruzada/efectos de los fármacos , Citoesqueleto/efectos de los fármacos , Citoesqueleto/metabolismo , Células Dendríticas/efectos de los fármacos , Células Dendríticas/inmunología , Gelsolina/química , Gelsolina/deficiencia , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Inmunidad/efectos de los fármacos , Ratones Endogámicos C57BL , Mutación/genética , Neoplasias/tratamiento farmacológico , Neoplasias/genética , Neoplasias/patología , Unión Proteica/efectos de los fármacos , Análisis de Supervivencia
5.
Commun Chem ; 4(1): 135, 2021 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-36697850

RESUMEN

Molecular surgery provides the opportunity to study relatively large molecules encapsulated within a fullerene cage. Here we determine the location of an H2O molecule isolated within an adsorbed buckminsterfullerene cage, and compare this to the intrafullerene position of HF. Using normal incidence X-ray standing wave (NIXSW) analysis, coupled with density functional theory and molecular dynamics simulations, we show that both H2O and HF are located at an off-centre position within the fullerene cage, caused by substantial intra-cage electrostatic fields generated by surface adsorption of the fullerene. The atomistic and electronic structure simulations also reveal significant internal rotational motion consistent with the NIXSW data. Despite this substantial intra-cage interaction, we find that neither HF or H2O contribute to the endofullerene frontier orbitals, confirming the chemical isolation of the encapsulated molecules. We also show that our experimental NIXSW measurements and theoretical data are best described by a mixed adsorption site model.

6.
Nano Lett ; 20(10): 7688-7693, 2020 10 14.
Artículo en Inglés | MEDLINE | ID: mdl-32866019

RESUMEN

Currently, researchers spend significant time manually searching through large volumes of data produced during scanning probe imaging to identify specific patterns and motifs formed via self-assembly and self-organization. Here, we use a combination of Monte Carlo simulations, general statistics, and machine learning to automatically distinguish several spatially correlated patterns in a mixed, highly varied data set of real AFM images of self-organized nanoparticles. We do this regardless of feature-scale and without the need for manually labeled training data. Provided that the structures of interest can be simulated, the strategy and protocols we describe can be easily adapted to other self-organized systems and data sets.


Asunto(s)
Nanopartículas , Nanoestructuras , Microscopía de Fuerza Atómica , Método de Montecarlo
7.
Bioessays ; 41(7): e1900021, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31157930

RESUMEN

This article reviews and discusses emerging evidence suggesting an evolutionarily-conserved connection between injury-associated exposure of cytoskeletal proteins and the induction of tolerance to infection, repair of tissue damage and restoration of homeostasis. While differences exist between vertebrates and invertebrates with respect to the receptor(s), cell types, and effector mechanisms involved, the response to exposed cytoskeletal proteins appears to be protective and to rely on a conserved signaling cassette involving Src family kinases, the nonreceptor tyrosine kinase Syk, and tyrosine phosphatases. A case is made for research programs that integrate different model organisms in order to increase the understanding of this putative response to tissue damage.


Asunto(s)
Proteínas del Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Regeneración/fisiología , Heridas y Lesiones/patología , Animales , Drosophila melanogaster/fisiología , Humanos , Proteínas Tirosina Fosfatasas/metabolismo , Transducción de Señal , Quinasa Syk/metabolismo , Familia-src Quinasas/metabolismo
8.
Elife ; 72018 09 27.
Artículo en Inglés | MEDLINE | ID: mdl-30260317

RESUMEN

Damage-associated molecular patterns (DAMPs) are molecules exposed or released by dead cells that trigger or modulate immunity and tissue repair. In vertebrates, the cytoskeletal component F-actin is a DAMP specifically recognised by DNGR-1, an innate immune receptor. Previously we suggested that actin is also a DAMP in Drosophila melanogaster by inducing STAT-dependent genes (Srinivasan et al., 2016). Here, we revise that conclusion and report that α-actinin is far more potent than actin at inducing the same STAT response and can be found in trace amounts in actin preparations. Recombinant expression of actin or α-actinin in bacteria demonstrated that only α-actinin could drive the expression of STAT target genes in Drosophila. The response to injected α-actinin required the same signalling cascade that we had identified in our previous work using actin preparations. Taken together, these data indicate that α-actinin rather than actin drives STAT activation when injected into Drosophila.


Asunto(s)
Actinina/farmacología , Actinas/farmacología , Proteínas de Drosophila/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Factores de Transcripción STAT/metabolismo , Actinina/administración & dosificación , Actinina/genética , Actinas/administración & dosificación , Actinas/genética , Animales , Animales Modificados Genéticamente , Drosophila melanogaster/genética , Drosophila melanogaster/metabolismo , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/farmacología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética
9.
PDA J Pharm Sci Technol ; 71(3): 206-224, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28196917

RESUMEN

This article reports the validation strategy used to demonstrate that the Milliflex® Quantum yielded non-inferior results to the traditional bioburden method. It was validated according to USP <1223>, European Pharmacopoeia 5.1.6, and Parenteral Drug Association Technical Report No. 33 and comprised the validation parameters robustness, ruggedness, repeatability, specificity, limit of detection and quantification, accuracy, precision, linearity, range, and equivalence in routine operation. For the validation, a combination of pharmacopeial ATCC strains as well as a broad selection of in-house isolates were used. In-house isolates were used in stressed state. Results were statistically evaluated regarding the pharmacopeial acceptance criterion of ≥70% recovery compared to the traditional method. Post-hoc test power calculations verified the appropriateness of the used sample size to detect such a difference. Furthermore, equivalence tests verified non-inferiority of the rapid method as compared to the traditional method. In conclusion, the rapid bioburden on basis of the Milliflex® Quantum was successfully validated as alternative method to the traditional bioburden test.LAY ABSTRACT: Pharmaceutical drug products must fulfill specified quality criteria regarding their microbial content in order to ensure patient safety. Drugs that are delivered into the body via injection, infusion, or implantation must be sterile (i.e., devoid of living microorganisms). Bioburden testing measures the levels of microbes present in the bulk solution of a drug before sterilization, and thus it provides important information for manufacturing a safe product. In general, bioburden testing has to be performed using the methods described in the pharmacopoeias (membrane filtration or plate count). These methods are well established and validated regarding their effectiveness; however, the incubation time required to visually identify microbial colonies is long. Thus, alternative methods that detect microbial contamination faster will improve control over the manufacturing process and speed up product release. Before alternative methods may be used, they must undergo a side-by-side comparison with pharmacopeial methods. In this comparison, referred to as validation, it must be shown in a statistically verified manner that the effectiveness of the alternative method is at least equivalent to that of the pharmacopeial methods. Here we describe the successful validation of an alternative bioburden testing method based on fluorescent staining of growing microorganisms applying the Milliflex® Quantum system by MilliporeSigma.


Asunto(s)
Contaminación de Medicamentos/prevención & control , Filtración/instrumentación , Técnicas Microbiológicas/instrumentación , Preparaciones Farmacéuticas/análisis , Recuento de Colonia Microbiana , Diseño de Equipo , Fluoresceínas/química , Colorantes Fluorescentes/química , Límite de Detección , Mediciones Luminiscentes , Reproducibilidad de los Resultados , Factores de Tiempo , Flujo de Trabajo
10.
Elife ; 52016 11 22.
Artículo en Inglés | MEDLINE | ID: mdl-27871362

RESUMEN

Damage-associated molecular patterns (DAMPs) are molecules released by dead cells that trigger sterile inflammation and, in vertebrates, adaptive immunity. Actin is a DAMP detected in mammals by the receptor, DNGR-1, expressed by dendritic cells (DCs). DNGR-1 is phosphorylated by Src-family kinases and recruits the tyrosine kinase Syk to promote DC cross-presentation of dead cell-associated antigens. Here we report that actin is also a DAMP in invertebrates that lack DCs and adaptive immunity. Administration of actin to Drosophila melanogaster triggers a response characterised by selective induction of STAT target genes in the fat body through the cytokine Upd3 and its JAK/STAT-coupled receptor, Domeless. Notably, this response requires signalling via Shark, the Drosophila orthologue of Syk, and Src42A, a Drosophila Src-family kinase, and is dependent on Nox activity. Thus, extracellular actin detection via a Src-family kinase-dependent cascade is an ancient means of detecting cell injury that precedes the evolution of adaptive immunity.


Asunto(s)
Actinas/metabolismo , Alarminas/metabolismo , Drosophila melanogaster/fisiología , Estrés Fisiológico , Animales , Transducción de Señal
11.
PDA J Pharm Sci Technol ; 69(3): 383-98, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26048745

RESUMEN

UNLABELLED: In the present work we compared different calculation approaches for their ability to accurately define microbiological control levels based on historical data. To that end, real microbiological data were used for simulation experiments. The results of our study confirmed that assuming a normal distribution is not appropriate for that purpose. In addition, assumption of a Poisson distribution generally underestimated the control level, and the predictive power for future values was highly insufficient. The non-parametric Excel percentile strongly predicted future values in our simulation experiments (although not as good as some of the parametric models). With the limited amount of data used in the simulations, the calculated control levels for the upper percentiles were on average higher and more variable compared to the parametric models. This was due to the fact that the largest observed value was generally defined as the control level. Accordingly, the Excel percentile is less robust towards outliers and requires more data to accurately define control levels as compared to parametric models. The negative binomial as well as the zero-inflated negative binomial distribution, both parametric models, had good predictive power for future values. Nonetheless, on basis of our simulation experiments, we saw no evidence to generally prefer the zero-inflated model over the non-inflated one. Finally, with our data, the gamma distribution on average had at least as good predictive power as the negative binomial distribution and zero-inflated negative binomial distribution for percentiles ≥98%, indicating that it may represent a viable option for calculating microbiological control levels at high percentiles. Presumably, this was based on the fact that the gamma distribution fitted the upper end of the distribution better than other models. Since in general microbiological control levels would be based on the upper percentiles, microbiologists may exclusively rely on the gamma distribution for calculation of their control levels. As the gamma distribution can conveniently be calculated in standard office calculation software, it may represent a superior alternative to the widely used percentile functions or other distribution models. LAY ABSTRACT: During the manufacturing of pharmaceutical drug products, the counts of microorganisms are monitored in the cleanroom environment, water, the product's raw materials, and the final product. This enables manufacturers to ensure that high numbers of microorganisms that may impair the product's microbiological quality are detected before the product is released to the patient. Microbiological control levels must be set to determine at which number a count is considered too high. Exceeding such levels may require an investigation to determine the root cause explaining why such high numbers of microorganisms occurred, and a set of actions should be performed with the aim of eliminating this root cause. In order to really differentiate higher-than-usual counts, microbiological control levels should be based on historical data. In the present work we analyzed different calculation approaches towards that purpose. We used real microbiological data and performed simulation experiments to determine which statistical method could calculate the most realistic control levels that would provide the best prediction for future routine testing. Better predictions would ensure that only significant contaminations lead to an excursion of the microbiological control level, which would avoid wasting resources by investigating non-issues or normal/controlled conditions.


Asunto(s)
Simulación por Computador , Monitoreo del Ambiente/métodos , Modelos Estadísticos , Preparaciones Farmacéuticas/normas , Distribución Binomial , Contaminación de Medicamentos , Industria Farmacéutica , Técnicas Microbiológicas , Distribución de Poisson
12.
PDA J Pharm Sci Technol ; 68(5): 394-406, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25336415

RESUMEN

Environmental monitoring represents an integral part of the microbiological quality control system of a pharmaceutical manufacturing operation. However, guidance documents differ regarding recommendation of a procedure, particularly regarding incubation time, incubation temperature, or nutrient media. Because of these discrepancies, many manufacturers decide for a particular environmental monitoring sample incubation strategy and support this decision with validation data. Such validations are typically laboratory-based in vitro studies, meaning that these are based on comparing incubation conditions and nutrient media through use of cultured microorganisms. An informal survey of the results of these in vitro studies performed at Novartis or European manufacturing sites of different pharmaceutical companies highlighted that no consensus regarding the optimal incubation conditions for microbial recovery existed. To address this question differently, we collected a significant amount of samples directly from air, inanimate surfaces, and personnel in pharmaceutical production and packaging rooms during manufacturing operation (in situ study). Samples were incubated under different conditions suggested in regulatory guidelines, and recovery of total aerobic microorganisms as well as moulds was assessed. We found the highest recovery of total aerobic count from areas with personnel flow using a general microbiological growth medium incubated at 30-35 °C. The highest recovery of moulds was obtained with mycological medium incubated at 20-25 °C. Single-plate strategies (two-temperature incubation or an intermediate incubation temperature of 25-30 °C) also yielded reasonable recovery of total aerobic count and moulds. However, recovery of moulds was found to be highly inefficient at 30-35 °C compared to lower incubation temperatures. This deficiency could not be rectified by subsequent incubation at 20-25 °C. A laboratory-based in vitro study performed in parallel was inconclusive. We consider our results potentially conferrable to other pharmaceutical manufacturing sites in moderate climate zones and believe that these should represent a valuable reference for definition of the incubation strategy of microbiological environmental monitoring samples. LAY ABSTRACT: Microbiological environmental monitoring confirms that pharmaceutical cleanrooms are in an appropriate hygienic condition for manufacturing of drug products. Guidance documents from different health authorities or expert groups differ regarding recommendation of the applied incubation time, incubation temperature, or nutrient media. Therefore, many pharmaceutical manufacturers perform studies that aim to identify the optimal incubation setup for environmental monitoring samples. An informal survey of the results of such studies, which had been performed at Novartis or European manufacturing sites of different pharmaceutical companies, highlighted no consensus regarding the optimal incubation conditions for microbial recovery. All these studies had been conducted in the laboratory using selections of cultured microbial strains. We tried to solve this disagreement by collecting a significant amount of real environmental monitoring samples directly from the environment in pharmaceutical production and packaging rooms during manufacturing operation. These samples were then incubated under different conditions suggested in the regulatory guidelines. We believe that the results of our study are more meaningful than laboratory-based experiments because we used environmental samples with microorganisms directly isolated from the manufacturing area. Therefore, we believe that our results should represent a valuable reference for definition of the incubation strategy of microbiological environmental monitoring samples.


Asunto(s)
Microbiología del Aire , Bacterias/crecimiento & desarrollo , Técnicas Bacteriológicas , Contaminación de Medicamentos/prevención & control , Ambiente Controlado , Monitoreo del Ambiente/métodos , Contaminación de Equipos , Hongos/crecimiento & desarrollo , Tecnología Farmacéutica/métodos , Microbiología del Aire/normas , Bacterias/aislamiento & purificación , Técnicas Bacteriológicas/normas , Consenso , Monitoreo del Ambiente/normas , Hongos/aislamiento & purificación , Tecnología Farmacéutica/normas , Temperatura , Factores de Tiempo
13.
Antimicrob Agents Chemother ; 54(10): 4208-18, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20660682

RESUMEN

Prosthetic joint replacements are used increasingly to alleviate pain and improve mobility of the progressively older and more obese population. Implant infection occurs in about 5% of patients and entails significant morbidity and high social costs. It is most often caused by staphylococci, which are introduced perioperatively. They are a source of prolonged seeding and difficult to treat due to antibiotic resistance; therefore, infection prevention by prosthesis coating with nonantibiotic-type anti-infective substances is indicated. A renewed interest in topically used silver has fostered development of silver nanoparticles, which, however, present a potential health hazard. Here we present new silver coordination polymer networks with tailored physical and chemical properties as nanostructured coatings on metallic implant substrates. These compounds exhibited strong biofilm sugar-independent bactericidal activity on in vitro-grown biofilms and prevented murine Staphylococcus epidermidis implant infection in vivo with slow release of silver ions and limited transient leukocyte cytotoxicity. Furthermore, we describe the biochemical and molecular mechanisms of silver ion action by gene screening and by targeting cell metabolism of S. epidermidis at different levels. We demonstrate that silver ions inactivate enzymes by binding sulfhydryl (thiol) groups in amino acids and promote the release of iron with subsequent hydroxyl radical formation by an indirect mechanism likely mediated by reactive oxygen species. This is the first report investigating the global metabolic effects of silver in the context of a therapeutic application. We anticipate that the compounds presented here open a new treatment field with a high medical impact.


Asunto(s)
Antibacterianos/uso terapéutico , Materiales Biocompatibles Revestidos/uso terapéutico , Radical Hidroxilo/metabolismo , Implantes Experimentales , Polímeros/uso terapéutico , Plata/uso terapéutico , Infecciones Estafilocócicas/prevención & control , Animales , Antibacterianos/química , Biopelículas/efectos de los fármacos , Materiales Biocompatibles Revestidos/química , Transporte de Electrón , Femenino , Ratones , Ratones Endogámicos C57BL , Polímeros/química , Plata/química , Staphylococcus epidermidis/efectos de los fármacos , Staphylococcus epidermidis/patogenicidad
14.
Antimicrob Agents Chemother ; 53(10): 4159-66, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19620329

RESUMEN

Brominated furanones from marine algae inhibit multicellular behaviors of gram-negative bacteria such as biofilm formation and quorum sensing (QS) without affecting their growth. The interaction of furanone with QS in gram-positive bacteria is unknown. Staphylococci have two QS systems, agr and luxS, which lower biofilm formation by two different pathways, RNAIII upregulation and bacterial detachment, and polysaccharide intercellular adhesin (PIA) reduction, respectively. We synthesized natural furanone compound 2 [(5Z)-4-bromo-5-(bromomethylene)-3-butyl-2(5H)-furanone] from Delisea pulchra and three analogues to investigate their effect on biofilm formation in gram-positive bacteria. Compound 2, but not the analogues, enhanced the biofilms of Staphylococcus epidermidis 1457 and 047 and of S. aureus Newman at concentrations between 1.25 and 20 microM. We show the growth inhibition of S. epidermidis and S. aureus by free furanone and demonstrate bactericidal activity. An induction of biofilm occurred at concentrations of 10 to 20% of the MIC and correlated with an increase in PIA. The biofilm effect was agr independent. It was due to interference with luxS, as shown by reduced luxS expression in the presence of compound 2 and independence of the strong biofilm formation in a luxS mutant upon furanone addition. Poly(l-lysine)-grafted/poly(ethylene glycol)-grafted furanone was ineffective on biofilm and not bactericidal, indicating the necessity for free furanone. Free furanone was similarly toxic for murine fibroblasts as for staphylococci, excluding a therapeutic application of this compound. In summary, we observed a biofilm enhancement by furanone in staphylococci at subinhibitory concentrations, which was manifested by an increase in PIA and dependent on luxS.


Asunto(s)
Proteínas Bacterianas/metabolismo , Biopelículas/efectos de los fármacos , Liasas de Carbono-Azufre/metabolismo , Furanos/farmacología , Staphylococcus/efectos de los fármacos , Staphylococcus/metabolismo , Animales , Proteínas Bacterianas/genética , Biopelículas/crecimiento & desarrollo , Liasas de Carbono-Azufre/genética , Línea Celular , Furanos/química , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Regulación Bacteriana de la Expresión Génica/genética , Ratones , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Polisacáridos Bacterianos/metabolismo , Percepción de Quorum/efectos de los fármacos , Staphylococcus/crecimiento & desarrollo
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