Dímero D en infección por COVID-19 / D-dimer in COVID-19 infection

CONTEXTO CLÍNICO: La enfermedad por el Coronavirus 2019 (COVID­19, por su sigla en inglés Coronavirus Disease 2019) es una enfermedad respiratoria de humanos producida por un nuevo coronavirus identificado con la sigla SARS-CoV-2. El 11 de marzo de 2020 la Organización Mundial de la Salud (OMS) declaro la infección por COVID-19 como una pandemia. Al 19 de junio de 2020 se han reportado 216 países afectados, 8.385.440 casos confirmados y 450.686 muertes. El período de incubación de la infección es de 2 a 14 días. La mayor parte de los contagios se producen persona a persona, siendo altamente transmisible. La clínica varía desde casos asintomáticos a cuadros febriles con tos y dificultad respiratoria, neumonía y distrés respiratorio. También puede acompañarse de alteraciones gastrointestinales. El departamento de medicina interna del Hospital de Brigham de la escuela de medicina de Harvard ha postulado una clasificación clínico-terapéutica de la enfermedad que divide el curso de la misma en diferentes etapas: Etapa I (leve), infección temprana: La etapa inicial ocurre en el momento de la inoculación y el establecimiento temprano de la enfermedad. Para la mayoría de las personas, esto implica un período de incubación asociado con síntomas leves y a menudo no específicos, como malestar general, fiebre y tos seca. Durante este período, el virus se multiplica y establece la residencia en el huésped, centrándose principalmente en el sistema respiratorio. En pacientes que pueden mantener el virus limitado a esta etapa de COVID-19, el pronóstico y la recuperación son excelentes. Etapa II compromiso pulmonar: En la segunda etapa de la enfermedad se establece el compromiso pulmonar, la multiplicación viral y la inflamación localizada en el pulmón es la norma. Los pacientes desarrollan una neumonía viral, con tos, fiebre y posiblemente hipoxia (definida como una PaO2/ FiO2<300 mmHg). Las imágenes (radiografía de tórax o tomografía computarizada) revelan infiltrados bilaterales u opacidades en vidrio esmerilado. Es en esta etapa que la mayoría de los pacientes con COVID-19 necesitarían ser hospitalizados para una observación y tratamiento cercanos. Etapa III (grave) de hiper-inflamación sistémica: Una minoría de pacientes pasará a la tercera y más grave etapa de la enfermedad, que se manifiesta como un síndrome de hiper-inflamación sistémica extrapulmonar. En esta etapa, los marcadores de inflamación sistémica parecen estar elevados. En general, el pronóstico y la recuperación de esta etapa crítica de la enfermedad es pobre, y el rápido reconocimiento y tratamiento podrían tener el mayor rendimiento. TECNOLOGÍA: El Dímero D es un producto de degradación de la fibrina y refleja la formación de coágulos sanguíneos y su posterior fibrinólisis.11 Es depurado por el riñón y, en menor medida, por el sistema retículo endotelial, siendo su vida media de 6 a 8 horas. Lo que se mide en un ensayo de Dímero D no es una molécula única, sino un conjunto heterogéneo de entidades liberadas por la plasmina de la fibrina y que contienen los dominios D adyacentes entrecruzados. El Dímero D tiene una sensibilidad muy alta para la enfermedad trombótica, pero su especificidad es menor ya que existen distintas condiciones fisiopatológicas en las cuales este marcador puede encontrarse elevado. Las causas más frecuentes que producen elevación del Dímero D en ausencia de enfermedad tromboembólica son, entre otras, la coagulopatía intravascular diseminada, la enfermedad renal, enfermedad hepática, hemorragia, infección, neoplasia, cirugías recientes, traumas, quemaduras, procesos inflamatorios, reabsorción de hematomas. A su vez, sus valores aumentan progresivamente con la edad. OBJETIVO: El objetivo del presente informe es evaluar la evidencia disponible acerca de la eficacia, seguridad, recomendaciones y aspectos relacionados a las políticas de cobertura del uso del Dímero D en COVID-19. MÉTODOS: Se realizó una búsqueda en las principales bases de datos bibliográficas, en buscadores genéricos de internet, y financiadores de salud. Se priorizó la inclusión de revisiones sistemáticas (RS), ensayos clínicos controlados aleatorizados (ECAs), evaluaciones de tecnologías sanitarias (ETS), evaluaciones económicas, guías de práctica clínica (GPC) y recomendaciones de diferentes organizaciones de salud. RESULTADOS: Se incluyeron dos RS, cuatro estudios observacionales, una ETS, ocho GPC o recomendaciones de sociedades científicas. No se encontró evidencia que permita establecer el beneficio clínico resultante del monitoreo de los niveles de dímero D en pacientes con infección por SarsCoV-2 como guía en la toma de decisiones terapéuticas que resulte en un cambio en desenlaces clínicos de importancia. CONCLUSIONES: Evidencia de moderada calidad sugiere que los niveles de Dímero D podrían ser un predictor independiente de mortalidad, progresión a enfermedad severa, enfermedad tromboembólica y de sangrado en pacientes con infección por SARS-CoV-2. No se encontró evidencia que permita establecer el beneficio clínico resultante del monitoreo de los niveles de dímero D en pacientes con infección por SarsCoV-2 como guía en la toma de decisiones terapéuticas que resulte en un cambio en desenlaces clínicos de importancia. La mayoría de guías de práctica clínica y recomendaciones relevadas, consideran al Dímero D como posible predictor de mortalidad y enfermedad severa, recomendando un monitoreo más estrecho en los pacientes con Dímero D elevado. Sin embargo, no hay consenso en todas las guías de práctica clínica y protocolos de manejo en recomendar que, en forma rutinaria, se les realice dosaje de Dímero D a todos los pacientes hospitalizados por COVID-19, ya que hay otros estudios de laboratorio disponibles (como tiempo de protrombina, tiempo de tromboplastina parcial activado y recuento de plaquetas). Asimismo, el aumento de Dímero D por sí solo, o en combinación con otros parámetros de laboratorio, no es suficiente para definir una conducta terapéutica.

A combined Far-FTIR, FTIR Spectromicroscopy, and DFT Study of the Effect of DNA Binding on the [4Fe4S] Cluster Site in EndoIII.

Endonuclease III (EndoIII) is a DNA glycosylase that contains the [4Fe4S] cluster, which is essential for the protein to bind to damaged DNA in a process called base excision repair (BER). Here we propose that the change in the covalency of Fe-S bonds of the [4Fe4S] cluster caused by double-stranded (ds)-DNA binding is accompanied by a change in their strength, which is due to alterations of the electronic structure of the cluster. Micro-FTIR spectroscopy in the mid-IR region and FTIR spectroscopy in the far IR (450 and 300 cm-1) were used independently to study the structural changes in EndoIII and the behavior of the [4Fe4S] cluster it contains, in the native form and upon its binding to ds-DNA. Structural changes in the DNA itself were also examined. The characteristics vibrational modes, corresponding to Fe-S (sulfide) and Fe-S (thiolate) bonds were identified in the cluster through far IR spectroscopy as well through quantum chemistry calculations. Based on the experimental results, these vibrational modes shift in their spectral positions caused by negatively charged DNA in the vicinity of the cluster. Modifications of the Fe-S bond lengths upon DNA binding, both of the Fe-S (sulfide) and Fe-S (thiolate) bonds in the [4Fe4S] cluster of EndoIII are responsible for the stabilization of the cluster towards higher oxidation state (3+), and hence its redox communication along the ds-DNA helix.

Genoprotective Effect of Phyllanthus orbicularis Extract Against UVA, UVB, and Solar Radiation.

One approach to protect the human skin against harmful effects of solar ultraviolet (UV) radiation was to use natural products as photoprotectors. In this work, the extract from specie Phyllanthus orbicularis K was evaluated as a protective agent against the photodamage by UVB, UVA artificial lamps, and environmental sunlight exposure. The plasmid DNA solutions were exposed to radiations using the DNA dosimeter system in the presence of plant extract. The DNA repair enzymes, Escherichia coli Formamidopyrimidine-DNA glycosylase (Fpg) and T4 bacteriophage endonuclease V (T4-endo V), were employed to discriminate oxidized DNA damage and cyclobutane pyrimidine dimers (CPD), respectively. The supercoiled and relaxed forms of DNA were separated through electrophoretic migration in agarose gels. These DNA forms were quantified to determine strand break, representing the types of lesion levels. The results showed that, in the presence of P. orbicularis extract, the CPD and oxidative damage were reduced in irradiated DNA samples. The photoprotective effect of extract was more evident for UVB and sunlight radiation than for UVA. This work documented the UV absorbing properties of P. orbicularis aqueous extract and opened up new vistas in its characterization as protective agent against DNA damage induced by environmental sunlight radiation.

Evaluation of imazethapyr-induced DNA oxidative damage by alkaline Endo III- and Fpg-modified single-cell gel electrophoresis assay in Hypsiboas pulchellus tadpoles (Anura, Hylidae).

Imazethapyr (IMZT) is a selective postemergent herbicide with residual action. Available data analyzing its effects in aquatic vertebrates are scarce. In previous studies, we demonstrated that IMZT induces lesions into the DNA of Hypsiboas pulchellus tadpoles using the single-cell gel electrophoresis (SCGE) assay as a biomarker for genotoxicity. Currently, this assay can be modified by including incubation with lesion-specific endonucleases, e.g., endonuclease III (Endo III) and formamidopyrimidine-DNA glycosylase (Fpg), which detect oxidized pyrimidine and purine bases, respectively. The aim of this study was to evaluate the role of oxidative stress in the genotoxic damage in circulating blood cells of H. pulchellus tadpoles exposed to the IMZT-based Pivot H® formulation (10.59% IMZT) at a concentration equivalent to 25% of the LC50 (96h) value (0.39mg/L IMZT) during 48 and 96h. Our results demonstrate that the herbicide induces oxidative DNA damage on H. pulchellus tadpoles at purines bases but not at pyrimidines. Our findings represent the first evidence of oxidative damage caused by IMZT on anuran DNA using the alkaline restriction enzyme-modified SCGE assay.

Genotoxicity of the herbicide imazethapyr in mammalian cells by oxidative DNA damage evaluation using the Endo III and FPG alkaline comet assays.

We evaluated the role of oxidative stress in the genotoxic damage induced by imazethapyr (IMZT) and its formulation Pivot® in mammalian CHO-K1 cell line. Using the alkaline comet assay, we observed that a concentration of 0.1 µg/mL of IMZT or Pivot® was able to induce DNA damage by increasing the frequency of damaged nucleoids. To test whether the DNA lesions were caused by oxidative stress, the DNA repair enzymes endonuclease III (Endo III) and formamidopyrimidine-DNA glycosylase (Fpg), which convert base damage to strand breaks, were used. Our results demonstrate that after treatment of CHO-K1 cells with the pure active ingredient as well as the commercial formulation Pivot®, an increase in DNA strand breaks was observed after incubation of both Endo III and Fpg enzymes, indicating that both compounds induce DNA damage involving both pyrimidine and purine-based oxidations, at least in CHO-K1 cells. Our findings confirm the genotoxic potential of IMZT and suggest that this herbicide formulation must be employed with great caution, especially not only for exposed occupational workers but also for other living species.

Nucleotide excision repair pathway assessment in DNA exposed to low-intensity red and infrared lasers.

Low-intensity lasers are used for prevention and management of oral mucositis induced by anticancer therapy, but the effectiveness of treatment depends on the genetic characteristics of affected cells. This study evaluated the survival and induction of filamentation of Escherichia coli cells deficient in the nucleotide excision repair pathway, and the action of T4endonuclease V on plasmid DNA exposed to low-intensity red and near-infrared laser light. Cultures of wild-type (strain AB1157) E. coli and strain AB1886 (deficient in uvrA protein) were exposed to red (660 nm) and infrared (808 nm) lasers at various fluences, powers and emission modes to study bacterial survival and filamentation. Also, plasmid DNA was exposed to laser light to study DNA lesions produced in vitro by T4endonuclease V. Low-intensity lasers:i) had no effect on survival of wild-type E. coli but decreased the survival of uvrA protein-deficient cells,ii) induced bacterial filamentation, iii) did not alter the electrophoretic profile of plasmids in agarose gels, andiv) did not alter the electrophoretic profile of plasmids incubated with T4 endonuclease V. These results increase our understanding of the effects of laser light on cells with various genetic characteristics, such as xeroderma pigmentosum cells deficient in nucleotide excision pathway activity in patients with mucositis treated by low-intensity lasers.

Nucleotide excision repair pathway assessment in DNA exposed to low-intensity red and infrared lasers

Low-intensity lasers are used for prevention and management of oral mucositis induced by anticancer therapy, but the effectiveness of treatment depends on the genetic characteristics of affected cells. This study evaluated the survival and induction of filamentation of Escherichia coli cells deficient in the nucleotide excision repair pathway, and the action of T4endonuclease V on plasmid DNA exposed to low-intensity red and near-infrared laser light. Cultures of wild-type (strain AB1157) E. coli and strain AB1886 (deficient in uvrA protein) were exposed to red (660 nm) and infrared (808 nm) lasers at various fluences, powers and emission modes to study bacterial survival and filamentation. Also, plasmid DNA was exposed to laser light to study DNA lesions produced in vitro by T4endonuclease V. Low-intensity lasers:i) had no effect on survival of wild-type E. coli but decreased the survival of uvrA protein-deficient cells,ii) induced bacterial filamentation, iii) did not alter the electrophoretic profile of plasmids in agarose gels, andiv) did not alter the electrophoretic profile of plasmids incubated with T4 endonuclease V. These results increase our understanding of the effects of laser light on cells with various genetic characteristics, such as xeroderma pigmentosum cells deficient in nucleotide excision pathway activity in patients with mucositis treated by low-intensity lasers.

DNA Base-Excision Repair Genes OGG1 and NTH1 in Brazilian Lung Cancer Patients.

INTRODUCTION: Lung cancer is the leading global cause of cancer-related mortality and is associated with poor prognosis. To improve survival rates of lung cancer patients, better understanding of tumorigenic mechanisms is necessary, which may lead to development of new therapeutic strategies. The hOGG1 and NTH1 genes act in the DNA BER repair pathway and their involvement in lung cancer pathogenesis has been analyzed in several populations. METHODS: We analyzed targeted regions of the hOGG1 and NTH1 genes in 96 Brazilian patients with non-small-cell lung cancer (NSCLC) and 89 cancer-free, ethnically matched controls. RESULTS: The NTH1 c.98G>T polymorphism rs2302172 (p = 0.02 and p = 0.02 for allele and genotype frequency between cases and controls, respectively) and the 140-17C> T variant (rs2233518) (p = 0.02 and p = 0.02 for allele and genotype frequency between cases and controls, respectively) were detected in four lung cancer cases (4 %) while the NTH1 Q131K (C391A) polymorphism was found in seven lung cancer cases (7 %) (p = 0.001 and p = 0.008, for allele and genotype frequency between cases and controls, respectively). None of these sequence variants were detected in controls. The Ser326Cys (C1245G, rs1052133) polymorphism in the OGG1 gene was detected in 42 % of analyzed NSCLC patients and in 34 % of the controls (p = 0.11 and p = 0.25 for allele and genotype frequency between cases and controls, respectively). CONCLUSIONS: Our study provides preliminary evidence that polymorphisms in OGG1 do not contribute to development of NSCLC in Brazilian patients and that NTH1 polymorphisms may be associated with NSCLC pathogenesis.

Adherence to abiotic surface induces SOS response in Escherichia coli K-12 strains under aerobic and anaerobic conditions.

During the colonization of surfaces, Escherichia coli bacteria often encounter DNA-damaging agents and these agents can induce several defence mechanisms. Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species (ROS) generated by chemical and physical agents or by metabolism. In this work, we have evaluated whether the interaction with an abiotic surface by mutants derived from E. coli K-12 deficient in some enzymes that are part of BER causes DNA damage and associated filamentation. Moreover, we studied the role of endonuclease V (nfi gene; 1506 mutant strain) in biofilm formation. Endonuclease V is an enzyme that is involved in DNA repair of nitrosative lesions. We verified that endonuclease V is involved in biofilm formation. Our results showed more filamentation in the xthA mutant (BW9091) and triple xthA nfo nth mutant (BW535) than in the wild-type strain (AB1157). By contrast, the mutant nfi did not present filamentation in biofilm, although its wild-type strain (1466) showed rare filaments in biofilm. The filamentation of bacterial cells attaching to a surface was a consequence of SOS induction measured by the SOS chromotest. However, biofilm formation depended on the ability of the bacteria to induce the SOS response since the mutant lexA Ind(-) did not induce the SOS response and did not form any biofilm. Oxygen tension was an important factor for the interaction of the BER mutants, since these mutants exhibited decreased quantitative adherence under anaerobic conditions. However, our results showed that the presence or absence of oxygen did not affect the viability of BW9091 and BW535 strains. The nfi mutant and its wild-type did not exhibit decreased biofilm formation under anaerobic conditions. Scanning electron microscopy was also performed on the E. coli K-12 strains that had adhered to the glass, and we observed the presence of a structure similar to an extracellular matrix that depended on the oxygen tension. In conclusion, it was proven that bacterial interaction with abiotic surfaces can lead to SOS induction and associated filamentation. Moreover, we verified that endonuclease V is involved in biofilm formation.

D-Dimer plasma levels in patients with coronary artery disease

We have previously reported that prothrombin fragment 1+2 levels were not associated to the presence or severity of coronary artery disease (CAD) and do not provide further information on subjects with CAD diagnosed by angiography. Thus, in the present study another marker of hypercoagulability was evaluated in the same subjects. This study aimed at determining D-Dimer plasma levels in a group of subjects undergoing coronary angiography to establish a likely relation between this parameter and the severity of CAD. D-Dimer plasma levels were determined in 17 subjects with no coronary atheromatosis (controls), 12 subjects with mild/moderate atheromatosis and 28 subjects with severe atheromatosis. No significant differences were observed among the three groups. Data analysis enables an inference on a tendency towards an increase in fibrinolytic activity in patients with atheromatosis, reflected by the increase in D-Dimer concentrations in the severe atheromatosis group in subjects with CAD diagnosed by coronary angiography.

Em estudo prévio, os níveis plasmáticos do fragmento 1+2 da protrombina não foram associados com a presença ou com a gravidade da doença arterial coronariana (DAC), não trazendo benefício adicional pelo menos em indivíduos com diagnóstico de DAC estabelecido por angiografia. Desta forma, neste estudo outro marcador de hipercoagulabilidade foi avaliado nos mesmos pacientes. O presente estudo teve como objetivo determinar os níveis plasmáticos do dímero D de um grupo de indivíduos submetidos à angiografia coronariana, buscando estabelecer a possível correlação entre este parâmetro e a gravidade da DAC. Os níveis plasmáticos do dímero D foram determinados em amostras de sangue de 17 indivíduos com ausência de ateromatose nas coronárias (controles), 12 indivíduos apresentando ateromatose leve/moderada e 28 indivíduos apresentando ateromatose grave. Não foram encontradas diferenças estatisticamente significativas entre as médias dos três grupos para o parâmetro avaliado. Uma análise dos dados permite inferir sobre uma tendência ao aumento da atividade fibrinolítica nos pacientes com ateromatose, refletida pela elevação da concentração de dímero D no grupo ateromatose grave em indivíduos com diagnóstico de DAC estabelecido por angiografia coronariana.

UV-specific DNA repair recombinant fusion enzyme: a new stable pharmacologically active principle suitable for photoprotection.

BACKGROUND: UV radiation can produce mutations in skin cells and correlates strongly with the onset of actinic keratoses and basal and squamous cell carcinomas. Xeroderma pigmentosum (XP) is a heritable disease characterized by an extreme sensitivity of skin to UV radiation. Recently, studies in cultured cells as well as in XP patients have demonstrated that the recombinant T4 endonuclease V UV-specific endonuclease could enhance repair of UV-induced photoproducts. OBJECTIVE: We aimed to obtain a stable UV-specific DNA recombinant endonuclease, pharmacologically active in mammalian cells so as to be used in treatment and prophylaxis of sun damage. METHODS: The UV-specific DNA endonuclease gene obtained from Micrococcus luteus, was fused to a leader peptide and expressed (alphaUveA), refolded and purified. A construction under the control of an eukaryotic promoter was used to transfect XP fibroblasts deficient in DNA damage repair. Transformed cells were UV irradiated and cell survival was assessed. RESULTS: alphaUveA was obtained as a highly active UV-specific repair enzyme stable for at least 2 years. XP fibroblasts transfected with alphaUveA gene increased the resistance to UV radiation and, in consequence, cell survival. CONCLUSION: alphaUveA is stable and pharmacologically active in human cells. The topical administration of this long-term stable new active principle could help diminish the risks of skin cancer after sun exposure.