RESUMO
OBJECTIVES: To identify sexual/sex-associated risk factors for hepatitis C transmission among men who have sex with men (MSM) and visualise behavioural trajectories from 2019 to 2021. METHODS: We linked a behavioural survey to a hepatitis C cohort study (NoCo), established in 2019 across six German HIV/hepatitis C virus (HCV) treatment centres, and performed a case-control analysis. Cases were MSM with recent HCV infection, and controls were matched for HIV status (model 1) or proportions of sexual partners with HIV (model 2). We conducted conditional univariable and multivariable regression analyses. RESULTS: In all, 197 cases and 314 controls completed the baseline questionnaire and could be matched with clinical data. For regression models, we restricted cases to those with HCV diagnosed since 2018 (N = 100). Factors independently associated with case status included sex-associated rectal bleeding, shared fisting lubricant, anal douching, chemsex, intravenous and intracavernosal injections, with population-attributable fractions of 88% (model 1) and 85% (model 2). These factors remained stable over time among cases, while sexual partner numbers and group sex decreased during COVID-19 measures. CONCLUSIONS: Sexual/sex-associated practices leading to blood exposure are key factors in HCV transmission in MSM. Public health interventions should emphasize the importance of blood safety in sexual encounters. Micro-elimination efforts were temporarily aided by reduced opportunities for sexual encounters during the COVID-19 pandemic.
Assuntos
Hepatite C , Homossexualidade Masculina , Humanos , Masculino , Fatores de Risco , Homossexualidade Masculina/estatística & dados numéricos , Adulto , Estudos de Casos e Controles , Hepatite C/transmissão , Hepatite C/epidemiologia , Pessoa de Meia-Idade , Comportamento Sexual/estatística & dados numéricos , Alemanha/epidemiologia , COVID-19/transmissão , COVID-19/epidemiologia , Infecções por HIV/transmissão , Parceiros Sexuais , SARS-CoV-2 , Inquéritos e Questionários , Estudos de CoortesRESUMO
INTRODUCTION: Direct-acting antivirals (DAAs) are key to eliminating hepatitis C virus (HCV). In men who have sex with men (MSM) with HIV co-infection, recently acquired HCV infection is common. Sexual practices and reinfection rates may hamper micro-elimination despite high treatment rates. METHODS: The cohort included MSM with recently acquired HCV infection from 2014 to 2021. The patients' demographic, clinical, behavioural, and laboratory data and treatment and reinfection outcomes were documented. RESULTS: A total of 237 men with recently acquired HCV infection were included: 216 (91%) had HIV. The median age was 46 years (interquartile range [IQR] 39-52), and the median CD4 count was 660/mm3 (IQR 527-835). The annual incidence of recently acquired HCV remained between 0.28% and 0.43% but dropped to 0.02% in 2021 during the COVID pandemic, almost reaching micro-elimination. The reinfection incidence was 15.5 per 100 patient-years (95% confidence interval 12.6-18.8), and reinfection was associated with the use of crystal methamphetamine (p = 0.032) and ketamine (p = 0.042). In total, 31.3% had multiple reinfections, and four reinfections occurred in users of pre-exposure prophylaxis. CONCLUSIONS: High treatment and cure rates did not lead to HCV elimination. A change in sexual behaviour, potentially imposed by COVID-19 restrictions, led to micro-elimination in the NoCo cohort. As recently acquired HCV is prevalent in MSM with and without HIV, surveillance is necessary to consolidate elimination goals.
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Antivirais , COVID-19 , Infecções por HIV , Hepatite C , Homossexualidade Masculina , Humanos , Masculino , Pessoa de Meia-Idade , Homossexualidade Masculina/estatística & dados numéricos , Antivirais/uso terapêutico , Adulto , Alemanha/epidemiologia , COVID-19/epidemiologia , COVID-19/prevenção & controle , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Infecções por HIV/complicações , Hepatite C/epidemiologia , Hepatite C/tratamento farmacológico , Incidência , Coinfecção/epidemiologia , Coinfecção/tratamento farmacológico , Reinfecção/epidemiologia , SARS-CoV-2RESUMO
A broad range of enzymes are used to modify starch for various applications. Here, a thermophilic 4-α-glucanotransferase from Thermoproteus uzoniensis (TuαGT) is engineered by N-terminal fusion of the starch binding domains (SBDs) of carbohydrate binding module family 20 (CBM20) to enhance its affinity for granular starch. The SBDs are N-terminal tandem domains (SBDSt1 and SBDSt2) from Solanum tuberosum disproportionating enzyme 2 (StDPE2) and the C-terminal domain (SBDGA) of glucoamylase from Aspergillus niger (AnGA). In silico analysis of CBM20s revealed that SBDGA and copies one and two of GH77 DPE2s belong to well separated clusters in the evolutionary tree; the second copies being more closely related to non-CAZyme CBM20s. The activity of SBD-TuαGT fusions increased 1.2-2.4-fold on amylose and decreased 3-9 fold on maltotriose compared with TuαGT. The fusions showed similar disproportionation activity on gelatinised normal maize starch (NMS). Notably, hydrolytic activity was 1.3-1.7-fold elevated for the fusions leading to a reduced molecule weight and higher α-1,6/α-1,4-linkage ratio of the modified starch. Notably, SBDGA-TuαGT and-SBDSt2-TuαGT showed Kd of 0.7 and 1.5 mg/mL for waxy maize starch (WMS) granules, whereas TuαGT and SBDSt1-TuαGT had 3-5-fold lower affinity. SBDSt2 contributed more than SBDSt1 to activity, substrate binding, and the stability of TuαGT fusions.
Assuntos
Sistema da Enzima Desramificadora do Glicogênio , Amido , Amido/química , Proteína 1 Semelhante a Receptor de Interleucina-1 , Sistema da Enzima Desramificadora do Glicogênio/genética , AmilopectinaRESUMO
Efficient inactivation of microbial α-amylases (EC 3.2.1.1) can be a challenge in starch systems as the presence of starch has been shown to enhance the stability of the enzymes. In this study, commonly used inactivation methods, including multistep washing and pH adjustment, were assessed for their efficiency in inactivating different α-amylases in presence of raw potato starch. Furthermore, an effective approach for irreversible α-amylase inactivation using sodium hypochlorite (NaOCl) is demonstrated. Regarding inactivation by extreme pH, the activity of five different α-amylases was either eliminated or significantly reduced at pH 1.5 and 12. However, treatment at extreme pH for 5 min, followed by incubation at pH 6.5, resulted in hydrolysis yields of 42-816% relative to controls that had not been subjected to extreme pH. "Inactivation" by multistep washing with water, ethanol, and acetone followed by gelatinization as preparation for analysis gave significant starch hydrolysis compared to samples inactivated with NaOCl before the wash. This indicates that the further starch degradation observed in samples subjected to washing only took place during the subsequent gelatinization. The current study demonstrates the importance of inactivation methodology in α-amylase-mediated raw starch depolymerization and provides a method for efficient α-amylase inactivation in starch systems.
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Solanum tuberosum , alfa-Amilases , alfa-Amilases/metabolismo , Solanum tuberosum/metabolismo , Hidrólise , Etanol , Amido/metabolismoRESUMO
BACKGROUND AND AIM: Heart failure (HF) and diabetes mellitus (DM) are burdensome chronic diseases with high lifetime risks and numerous studies indicate associations between HF and DM. The objective of this study was to investigate the direct and indirect costs of HF patients with and without DM. METHODS AND RESULTS: Patients with a first-time diagnosis of HF from 1998 to 2016 were identified through nationwide Danish registries and stratified according to DM status into HF with or without DM. The economic healthcare cost analysis was based on both direct costs, including hospitalization, procedures, medication and indirect costs including social welfare and lost productivity. The economic burden was investigated prior to, at, and following diagnosis of HF. Patients with concomitant HF and DM were younger (median age 74 vs. 77), had more comorbidities and fewer were female as compared to patients with HF but without DM. The socioeconomic burden of concomitant HF and DM compared to HF alone was substantially higher; 45% in direct costs (16,237 vs. 11,184), 35% in home care costs (3123 vs. 2320), 8% in social transfer income (17,257 vs. 15,994) and they had 27% lower income (10,136 vs. 13,845). The economic burden peaked at year of diagnosis, but the difference became increasingly pronounced in the years following the HF diagnosis. CONCLUSION: Patients with concomitant HF and DM had a significantly higher economic burden compared to patients with HF but without DM.
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Diabetes Mellitus , Insuficiência Cardíaca , Idoso , Efeitos Psicossociais da Doença , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologia , Diabetes Mellitus/terapia , Feminino , Custos de Cuidados de Saúde , Insuficiência Cardíaca/diagnóstico , Insuficiência Cardíaca/epidemiologia , Insuficiência Cardíaca/terapia , Hospitalização , Humanos , MasculinoRESUMO
Improvement of health-related quality of life (HRQoL) is frequently reported as a benefit when treating hepatitis C virus infection (HCV) with direct acting antivirals (DAA). As most of the available data were obtained from clinical trials, limited generalizability to the real-world population might exist. This study aimed to investigate the impact of DAA therapy on changes in HRQoL in a real-world setting. HRQoL of 1180 participants of the German Hepatitis C-Registry was assessed by Short-Form 36 (SF-36) questionnaires. Scores at post-treatment weeks 12-24 (FU12/24) were compared to baseline (BL). Changes of ≥2.5 in mental and physical component summary scores (MCS and PCS) were defined as a minimal clinical important difference (MCID). Potential predictors of HRQoL changes were analysed. Overall, a statistically significant increase in HRQoL after DAA therapy was observed, that was robust among various subgroups. However, roughly half of all patients failed to achieve a clinically important improvement in MCS and PCS. Low MCS (p < .001, OR = 0.925) and PCS (p < .001, OR = 0.899) BL levels were identified as predictors for achieving a clinically important improvement. In contrast, presence of fatigue (p = .023, OR = 1.518), increased GPT levels (p = .005, OR = 0.626) and RBV containing therapy regimens (p = .001, OR = 1.692) were associated with a clinically important decline in HRQoL after DAA therapy. In conclusion, DAA treatment is associated with an overall increase of HRQoL in HCV-infected patients. Nevertheless, roughly half of the patients fail to achieve a clinically important improvement. Especially patients with a low HRQoL seem to benefit most from the modern therapeutic options.
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Hepatite C Crônica , Hepatite C , Antivirais/uso terapêutico , Hepacivirus , Hepatite C/tratamento farmacológico , Hepatite C Crônica/tratamento farmacológico , Humanos , Qualidade de Vida , Sistema de Registros , Resultado do TratamentoRESUMO
BACKGROUND: Micro-elimination of the hepatitis C virus (HCV) includes treatment in populations at risk of ongoing HCV transmission, such as men who have sex with men (MSM) or people who inject drugs (PWID). We analyzed the HCV reinfection incidence rates of participants in the German hepatitis C cohort (GECCO) and compared our data to previous findings from the interferon era. METHODS: Patients with HCV reinfections in the multi-centric GECCO cohort were compared to patients in whom no reinfection occurred. The HCV reinfection incidence rate in MSM was also compared to the incidence rate in the interferon era (using data from the European Acquired Immunodeficiency Syndrome Treatment Network [NEAT]). RESULTS: Between January 2014 and April 2018, 48 HCV reinfections occurred in 2298 individuals (2%), with 2346 cured HCV episodes. The median time to reinfection was 500 days (range 16-1160) and the overall HCV reinfection incidence rate was 1.89 per 100 person-years (py; 95% confidence interval [CI], 1.41-2.48). In a multivariate analysis, the transmission risk in MSM was the only independent risk factor of HCV reinfection (odds ratio, 39.3; 95% CI, 4.57-334.40; P = .001). The incidence rate in MSM was 9.02 (95% CI, 6.48-12.26) per 100 py, compared to 1.14 per 100 py in PWID (95% CI, .56-2.09). The incidence rate for a first HCV reinfection in MSM was similar in the direct-acting antiviral era, compared to the interferon era, with a hazard ratio of 1.05 (95% CI, .64-1.74; P = .831). CONCLUSIONS: HCV reinfection remains a frequent finding among MSM in Germany. In addition to behavioral interventions, early HCV treatment and retreatment should be implemented for this subgroup to prevent HCV transmission.
Assuntos
Infecções por HIV , Hepatite C Crônica , Hepatite C , Preparações Farmacêuticas , Minorias Sexuais e de Gênero , Abuso de Substâncias por Via Intravenosa , Antivirais/uso terapêutico , Alemanha/epidemiologia , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Hepacivirus , Hepatite C/tratamento farmacológico , Hepatite C/epidemiologia , Hepatite C Crônica/tratamento farmacológico , Homossexualidade Masculina , Humanos , Incidência , Interferons/uso terapêutico , Masculino , Recidiva , Reinfecção , Abuso de Substâncias por Via Intravenosa/tratamento farmacológicoRESUMO
GOALS AND BACKGROUND: International guidelines recommend prioritized treatment initiation in hepatitis C virus (HCV)-infected patients with advanced liver disease. We aimed to evaluate whether the widespread usage of direct acting antivirals (DAAs) has led to a decrease in late presentation for care. STUDY: Data derived from the multicenter German Hepatitis C Cohort (GECCO) was analyzed. Treatment naive HCV-infected patients initiating DAA-based treatment between January 2014 and September 2017 were included. Advanced liver disease was defined by aspartate aminotransferase to platelet ratio index score ≥1.5, METAVIR≥F3, or FibroScan ≥9.5 kPa. Period prevalence and risk factors for late presentation were evaluated. RESULTS: Six hundred fifty-three HCV-monoinfected and 210 HIV/HCV-coinfected patients (mean age, 48.6±12.7 y; 65.5% male) were included. Overall 32.5% of patients had advanced liver disease. In 2014 39.4% of patients presented with advanced liver disease, decreasing to 30.1%, 34.4%, and 26.4% in the years 2015, 2016, and 2017 (P=0.057), respectively. Patients with and without advanced liver disease differed in age (P<0.0001), CD4 ≤350/µL (P=0.027), genotype (P=0.005), transmission route (P=0.047), body mass index (P<0.001), and time since diagnosis (P=0.007). In the multivariable binary logistic regression analysis GT3, age above 45 years and being diagnosed >2 years ago were positively and HCV transmission through men who have sex with men was negatively associated with advanced liver disease. CONCLUSIONS: Overall 32.5% of patients presented with advanced liver disease. We observed a trend toward a lower proportion of patients starting treatment late.GT3, age, years since HCV diagnosis and HCV transmission route were identified as risk factors for presentation with advanced liver disease.
Assuntos
Coinfecção , Infecções por HIV , Hepatite C Crônica , Hepatite C , Minorias Sexuais e de Gênero , Adulto , Antivirais/uso terapêutico , Coinfecção/tratamento farmacológico , Feminino , Alemanha/epidemiologia , Infecções por HIV/complicações , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Hepacivirus , Hepatite C/complicações , Hepatite C/tratamento farmacológico , Hepatite C/epidemiologia , Hepatite C Crônica/complicações , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/epidemiologia , Homossexualidade Masculina , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Cellobiohydrolases (CBHs) from glycoside hydrolase family 6 (GH6) make up an important part of the secretome in many cellulolytic fungi. They are also of technical interest, particularly because they are part of the enzyme cocktails that are used for the industrial breakdown of lignocellulosic biomass. Nevertheless, functional studies of GH6 CBHs are scarce and focused on a few model enzymes. To elucidate functional breadth among GH6 CBHs, we conducted a comparative biochemical study of seven GH6 CBHs originating from fungi living in different habitats, in addition to one enzyme variant. The enzyme sequences were investigated by phylogenetic analyses to ensure that they were not closely related phylogenetically. The selected enzymes were all heterologously expressed in Aspergillus oryzae, purified and thoroughly characterized biochemically. This approach allowed direct comparisons of functional data, and the results revealed substantial variability. For example, the adsorption capacity on cellulose spanned two orders of magnitude and kinetic parameters, derived from two independent steady-state methods also varied significantly. While the different functional parameters covered wide ranges, they were not independent since they changed in parallel between two poles. One pole was characterized by strong substrate interactions, high adsorption capacity and low turnover number while the other showed weak substrate interactions, poor adsorption and high turnover. The investigated enzymes essentially defined a continuum between these two opposites, and this scaling of functional parameters raises interesting questions regarding functional plasticity and evolution of GH6 CBHs.
Assuntos
Celulose 1,4-beta-Celobiosidase , Evolução Molecular , Proteínas Fúngicas , Fungos , Filogenia , Celulose 1,4-beta-Celobiosidase/química , Celulose 1,4-beta-Celobiosidase/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Fungos/enzimologia , Fungos/genética , Especificidade da EspécieRESUMO
BACKGROUND: Despite high hepatitis C virus (HCV) treatment rates, HCV incidence among human immunodeficiency virus (HIV)-infected men who have sex with men (HIV-infected MSM) in Germany rose before HCV direct-acting antivirals (DAAs). We model what intervention can achieve the World Health Organization (WHO) elimination target of an 80% reduction in HCV incidence by 2030 among HIV-infected MSM in Berlin. METHODS: An HCV transmission model among HIV-diagnosed MSM was calibrated to Berlin (rising HCV incidence and high rates of HCV testing and treatment). We modeled the HCV incidence among HIV-diagnosed MSM in Berlin until 2030 (relative to 2015 WHO baseline) under scenarios of DAA scale-up with or without behavior change (among HIV-diagnosed MSM and/or all MSM). RESULTS: Continuing current treatment rates will marginally reduce the HCV incidence among HIV-diagnosed MSM in Berlin by 2030. Scaling up DAA treatment rates, beginning in 2018, to 100% of newly diagnosed HCV infections within 3 months of diagnosis and 25% each year of previously diagnosed and untreated HCV infections could reduce the HCV incidence by 61% (95% confidence interval, 55.4%-66.7%) by 2030. The WHO target would likely be achieved by combining DAA scale-up with a 40% reduction in HCV transmission among HIV-diagnosed MSM and a 20% reduction among HIV-undiagnosed or HIV-uninfected MSM. DISCUSSION: HCV elimination among HIV-infected MSM in Berlin likely requires combining DAA scale-up with moderately effective behavioral interventions to reduce risk among all MSM.
Assuntos
Antivirais/uso terapêutico , Terapia Comportamental/métodos , Infecções por HIV/complicações , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/epidemiologia , Homossexualidade Masculina , Adulto , Berlim/epidemiologia , Transmissão de Doença Infecciosa/prevenção & controle , Hepatite C Crônica/transmissão , Humanos , Incidência , Masculino , Modelos Estatísticos , Resultado do Tratamento , Adulto JovemRESUMO
Measurement of steady-state rates (vSS) is straightforward in standard enzymology with soluble substrate, and it has been instrumental for comparative biochemical analyses within this area. For insoluble substrate, however, experimental values of vss remain controversial, and this has strongly limited the amount and quality of comparative analyses for cellulases and other enzymes that act on the surface of an insoluble substrate. In the current work, we have measured progress curves over a wide range of conditions for two cellulases, TrCel6A and TrCel7A from Trichoderma reesei, acting on their natural, insoluble substrate, cellulose. Based on this, we consider practical compromises for the determination of experimental vSS values, and propose a basic protocol that provides representative reaction rates and is experimentally simple so that larger groups of enzymes and conditions can be readily assayed with standard laboratory equipment. We surmise that the suggested experimental approach can be useful in comparative biochemical studies of cellulases; an area that remains poorly developed.
Assuntos
Produtos Biológicos/metabolismo , Celulases/metabolismo , Celulose/metabolismo , Produtos Biológicos/química , Celulose/química , Cinética , Solubilidade , Propriedades de Superfície , Trichoderma/enzimologiaRESUMO
BACKGROUND AND AIMS: Disease activity, but also demographics, lifestyle, and comorbidities, may influence alanine aminotransferase (ALT) levels in hepatitis C virus (HCV)-infected patients. Direct-acting antiviral agents (DAA) achieve virological cure in >â90â% of patients, regardless of HCV genotype and fibrosis stage. This allows assessing determinants for ALT levels before and after elimination of HCV. METHODS: Our prospective cohort included HCV- and HIV/HCV-infected patients treated with DAA at 9 German centers (GECCO cohort). We analyzed all consecutive patients with sustained virological response (SVR) at week 12 (SVR12) and/or 24. Normal ALT was defined as ≤â35âU/L, regardless of sex. RESULTS: At baseline, 1477 out of 1774 patients (83â%) had ALT >â35âU/L, and 297 (17â%) had ALT ≤â35âU/L. Baseline ALT >â35âU/L was independently associated with male sex, higher body mass index (BMI), liver cirrhosis, and not being on opioid substitution. After SVR, >â80â% of patients normalized ALT, and even patients with low baseline ALT further reduced ALT levels. However, ALT remained >â35âU/L in 15â% (221/1477) after SVR12. By multivariate analysis, ALT >â35âU/L at SVR12 was associated with male sex, higher BMI, liver cirrhosis, baseline ALT, HCV genotype 2, and younger age. Obesity, cirrhosis, and ALT were also independent factors associated with ALT >â15âU/L at SVR12 in patients with normal ALT at baseline. CONCLUSIONS: Male sex, advanced liver fibrosis, and obesity are main risk factors for the lack of ALT normalization and/or ALT decline after SVR, indicative of fatty liver disease as a relevant comorbidity in hepatitis C.
Assuntos
Alanina Transaminase , Fígado Gorduroso , Hepatite C Crônica , Alanina Transaminase/sangue , Antivirais , Fígado Gorduroso/complicações , Fígado Gorduroso/epidemiologia , Feminino , Hepacivirus , Hepatite C Crônica/epidemiologia , Humanos , Cirrose Hepática/complicações , Cirrose Hepática/epidemiologia , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/epidemiologia , Estudos Prospectivos , Ribavirina , Fatores de Risco , Fatores SexuaisRESUMO
There are limited data regarding the real world effectiveness of direct acting antivirals (DAA) for the therapy of chronic genotype 3 hepatitis C virus (HCV) infection. All HCV genotype 3 infected patients from the German hepatitis C cohort (GECCO), which is a prospective database of nine German hepatitis C treatment centers, were included in the study. Three hundred forty-two chronically infected HCV genotype 3 patients were analyzed (253 males [74.0%], mean age 47.3 years, 127 cirrhotic patients [37.1%] mostly with Child A cirrhosis, 113 treatment experienced patients [37.1%], 38 HCV/HIV co-infected patients [11.1%]). SVR12 rates in the "intention-to-treat" analysis were as follows: sofosbuvir/ribavirin 69.4% (75/108), sofosbuvir/peginterferon/ribavirin 80.6% (58/72), sofosbuvir/daclatasvir ± ribavirin for 12 weeks 88.3% (53/63), sofosbuvir/daclatasvir ± ribavirin for 24 weeks 79.3% (23/29), sofosbuvir/ledipasvir ± ribavirin for 12 weeks 71.4% (10/14), and sofosbuvir/ledipasvir ± ribavirin for 24 weeks 86.7% (26/30). Forty patients were lost to follow-up, 23 patients had a relapse, 4 patients stopped treatment prematurely and 1 patient died. Female sex (P = 0.038) and treatment with two different DAAs (P = 0.05) were predictors for SVR12 in the multivariate analysis. In conclusion, sofosbuvir/daclatasvir ± ribavirin for 12 weeks and sofosbuvir/ledipasvir ± ribavirin for 24 weeks are effective for the treatment of HCV genotype 3 infected patients including cirrhotic, treatment-experienced or HIV/HCV co-infected patients.
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Antivirais/uso terapêutico , Genótipo , Hepacivirus/classificação , Hepatite C Crônica/tratamento farmacológico , Sofosbuvir/uso terapêutico , Adulto , Idoso , Quimioterapia Combinada/métodos , Feminino , Hepacivirus/genética , Hepatite C Crônica/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Resposta Viral Sustentada , Resultado do TratamentoRESUMO
We have measured activity and substrate affinity of the thermostable cellobiohydrolase, Cel7A, from Rasamsonia emersonii over a broad range of temperatures. For the wild type enzyme, which does not have a Carbohydrate Binding Module (CBM), higher temperature only led to moderately increased activity against cellulose, and we ascribed this to a pronounced, temperature induced desorption of enzyme from the substrate surface. We also tested a "high affinity" variant of R. emersonii Cel7A with a linker and CBM from a related enzyme. At room temperature, the activity of the variant was similar to the wild type, but the variant was more accelerated by temperature and about two-fold faster around 70 °C. This better thermoactivation of the high-affinity variant could not be linked to differences in stability or the catalytic process, but coincided with less desorption as temperature increased. Based on these observations and earlier reports on moderate thermoactivation of cellulases, we suggest that better cellulolytic activity at industrially relevant temperatures may be attained by engineering improved substrate affinity into enzymes that already possess good thermostability.
Assuntos
Ascomicetos/enzimologia , Celulose 1,4-beta-Celobiosidase/metabolismo , Proteínas Fúngicas/metabolismo , Temperatura Alta , Catálise , Domínio Catalítico , Celulose/metabolismo , Colorimetria , Glicosídeos/metabolismo , Himecromona/análogos & derivados , Himecromona/metabolismo , Ligação Proteica , Estabilidade ProteicaRESUMO
Cellulose degrading fungi such as Hypocrea jecorina secrete several cellulases including the two cellobiohydrolases (CBHs) Cel6A and Cel7A. The two CBHs differ in catalytic mechanism, attack different ends, belong to different families, but are both processive multi-domain enzymes that are essential in the hydrolysis of cellulose. Here we present a direct kinetic comparison of these two enzymes acting on insoluble cellulose. We used both continuous- and end-point assays under either enzyme- or substrate excess, and found distinct kinetic differences between the two CBHs. Cel6A was catalytically superior with a maximal rate over four times higher than Cel7A. Conversely, the ability of Cel6A to attack diverse structures on the cellulose surface was inferior to Cel7A. This latter difference was pronounced as the density of attack sites for Cel7A was almost an order of magnitude higher compared to Cel6A. We conclude that Cel6A is a fast but selective enzyme and that Cel7A is slower, but promiscuous. One consequence of this is that Cel6A is more effective when substrate is plentiful, while Cel7A excels when substrate is limiting. These diverse kinetic properties of Cel6A and Cel7A might elucidate why both cellobiohydrolases are prominent in cellulolytic degrading fungi.
Assuntos
Celulose 1,4-beta-Celobiosidase/metabolismo , Hypocrea/enzimologia , Biocatálise , CinéticaRESUMO
Synergy between cellulolytic enzymes is essential in both natural and industrial breakdown of biomass. In addition to synergy between endo- and exo-lytic enzymes, a lesser known but equally conspicuous synergy occurs among exo-acting, processive cellobiohydrolases (CBHs) such as Cel7A and Cel6A from Hypocrea jecorina. We studied this system using microcrystalline cellulose as substrate and found a degree of synergy between 1.3 and 2.2 depending on the experimental conditions. Synergy between enzyme variants without the carbohydrate binding module (CBM) and its linker was strongly reduced compared to the wild types. One plausible interpretation of this is that exo-exo synergy depends on the targeting role of the CBM. Many earlier works have proposed that exo-exo synergy was caused by an auxiliary endo-lytic activity of Cel6A. However, biochemical data from different assays suggested that the endo-lytic activity of both Cel6A and Cel7A were 103 -104 times lower than the common endoglucanase, Cel7B, from the same organism. Moreover, the endo-lytic activity of Cel7A was 2-3-fold higher than for Cel6A, and we suggest that endo-like activity of Cel6A cannot be the main cause for the observed synergy. Rather, we suggest the exo-exo synergy found here depends on different specificities of the enzymes possibly governed by their CBMs. Biotechnol. Bioeng. 2017;114: 1639-1647. © 2017 Wiley Periodicals, Inc.
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Celulose/química , Proteínas Fúngicas/química , Hypocrea/enzimologia , Sítios de Ligação , Sinergismo Farmacológico , Ativação Enzimática , Complexos Multienzimáticos , Ligação Proteica , Especificidade por SubstratoRESUMO
BACKGROUND & AIMS: There are few large-scale, prospective studies comparing liver-associated events in treated and untreated patients with CHC managed in routine clinical practice. METHODS: Patients with CHC were prospectively enrolled in a non-interventional study. Data from patients with available documentation who had either achieved a sustained virological response, or were non-responders, relapsers, or had virological breakthrough following treatment with peginterferon alfa-2a±ribavirin, or who had been diagnosed but never treated at least 3 years previously, and who remained under medical observation were analyzed. Primary endpoint was liver-associated events (composite of decompensation/liver failure, ascites, hepatocellular carcinoma, or liver transplant/placement on a transplant list). RESULTS: In all, 1444 eligible patients were identified. Mean follow-up was 4.7 (standard deviation; SD 1.1) years. Patients with sustained virological response had a lower incidence of liver-associated events vs non-responders, relapsers, or virological breakthrough and never treated patients (1.7% vs 4.7% and 4.7% respectively). The proportion of patients with cirrhosis increased from baseline in the non-responders, relapsers, or virological breakthrough (6.8%-10.5%) and never treated group (3.7%-8.4%), with an associated increase in severity, but was unchanged in the sustained virological response group (2.1%). Event-free survival was significantly higher in sustained virological response patients (P=.0082). CONCLUSIONS: In this "real-world" cohort, the achievement of sustained virological response almost eliminated liver-related morbidity and mortality compared with patients who failed to achieve sustained virological response and those who were untreated. Overall, the LOTOS cohort highlights the importance of timely and effective treatment for patients with CHC.
Assuntos
Antivirais/uso terapêutico , Hepatite C Crônica/tratamento farmacológico , Interferon-alfa/uso terapêutico , Polietilenoglicóis/uso terapêutico , Adulto , Idoso , Carcinoma Hepatocelular/mortalidade , Carcinoma Hepatocelular/cirurgia , Carcinoma Hepatocelular/virologia , Bases de Dados Factuais , Feminino , Alemanha , Hepatite C Crônica/diagnóstico , Hepatite C Crônica/mortalidade , Hepatite C Crônica/virologia , Humanos , Falência Hepática/mortalidade , Falência Hepática/cirurgia , Falência Hepática/virologia , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/cirurgia , Neoplasias Hepáticas/virologia , Transplante de Fígado , Masculino , Pessoa de Meia-Idade , Vigilância de Produtos Comercializados , Estudos Prospectivos , Proteínas Recombinantes/uso terapêutico , Recidiva , Fatores de Risco , Resposta Viral Sustentada , Fatores de Tempo , Resultado do TratamentoRESUMO
BACKGROUND: Shortening the duration of treatment with HCV direct-acting antivirals (DAAs) leads to substantial cost reductions. According to the label, sofosbuvir and ledipasvir can be prescribed for 8 weeks (SL8) in noncirrhotic women or men with HCV genotype 1 and low viral loads. However, real-world data about the efficacy and safety of SL8 are largely missing. METHODS: Interim results from an ongoing prospective, multicenter cohort of 9 treatment centers in Germany (GECCO). All patients started on treatment with HCV DAAs since January 2014 were included. This report describes safety and efficacy outcomes in 210 patients with HCV monoinfection and 35 with human immunodeficiency virus (HIV)-HCV coinfection given SL8 in a real-world setting. RESULTS: Of 1353 patients included into the GECCO cohort until December 2015, a total of 1287 had complete data sets for this analysis; 337 (26.2%) fulfilled the criteria for SL8 according to the package insert, but only 193 (57.2%) were eventually treated for 8 weeks. Another 52 patients did not fulfill the criteria but were treated for 8 weeks. SL8 was generally well tolerated. The overall sustained virologic response rate 12 weeks after the end of treatment was 93.5% (186 of 199). The on-treatment response rate was 99.4% (159 of 160) in HCV-monoinfected and 96.4% (27 of 28) in HIV-HCV-coinfected patients. Ten patients were lost to follow-up. CONCLUSIONS: SL8 seems highly effective and safe in well-selected HCV-monoinfected and HIV-HCV-coinfected patients in a real-world setting.
Assuntos
Antivirais , Benzimidazóis , Coinfecção/tratamento farmacológico , Fluorenos , Infecções por HIV/complicações , Hepatite C Crônica/tratamento farmacológico , Sofosbuvir , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antivirais/administração & dosagem , Antivirais/uso terapêutico , Benzimidazóis/administração & dosagem , Benzimidazóis/uso terapêutico , Feminino , Fluorenos/administração & dosagem , Fluorenos/uso terapêutico , Alemanha/epidemiologia , Hepatite C Crônica/complicações , Hepatite C Crônica/epidemiologia , Hepatite C Crônica/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Sofosbuvir/administração & dosagem , Sofosbuvir/uso terapêutico , Carga Viral , Adulto JovemRESUMO
OBJECTIVE: To describe potential drug-drug interactions in the area of HIV/hepatitis C virus (HCV) coinfection and injection drug use, including those between antiretrovirals (ARVs), direct-acting antivirals (DAAs), and opioid-agonist therapy, and to supply a practical approach to their management. DATA SOURCES: We searched PubMed for relevant articles published up until February 2015 as well as conference reports and drug-drug-interaction Web sites. DATA SELECTION AND DATA EXTRACTION: We used the following search terms: pharmacokinetic and pharmacodynamic drug-drug interaction, opioid substitution, HIV, hepatitis and the individual names of the relevant agents of the following drug classes and the drug classes itself: reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, protease inhibitors, direct-acting antivirals, opioide, benzodiazepines, anticonvulsants, antidepressants and antipsychotics. Additional references were identified from a review of literature citations and drug-drug interaction Web sites. In our evaluation, we included German- and English-language studies and reports addressing drug-drug interactions between opioid agonist therapy and ARVs or DAAs. DATA SYNTHESIS: Pharmacokinetic data were available for all ARVs and DAAs except rilpivirine, indinavir, saquinavir, maraviroc, dolutegravir, and MK-8742 with buprenorphine as well as maraviroc with methadone Drug-drug interactions of potential clinical relevance are most likely to occur between opioid-replacement therapy and ARVs, particularly the nonnucleoside reverse transcriptase inhibitors, efavirenz and nevirapine, and HIV protease inhibitors. CONCLUSION: Integrase inhibitors may be safely coadministered with opioid-replacement therapy. With respect to HCV DAAs, most currently approved and late-stage investigational agents do not have clinically significant interactions with opioid-replacement therapy. ARV and DAAs may interact with other drug classes commonly used in the opioid-dependent population, including benzodiazepines, antidepressants, anticonvulsants, and antipsychotics.
Assuntos
Analgésicos Opioides/uso terapêutico , Antivirais/uso terapêutico , Infecções por HIV/tratamento farmacológico , Hepatite C/tratamento farmacológico , Metadona/uso terapêutico , Abuso de Substâncias por Via Intravenosa/tratamento farmacológico , Analgésicos Opioides/efeitos adversos , Antivirais/efeitos adversos , Coinfecção , Interações Medicamentosas , Infecções por HIV/complicações , Inibidores da Protease de HIV/efeitos adversos , Inibidores da Protease de HIV/uso terapêutico , Hepatite C/complicações , Humanos , Metadona/efeitos adversos , Tratamento de Substituição de Opiáceos , Inibidores da Transcriptase Reversa/efeitos adversos , Inibidores da Transcriptase Reversa/uso terapêutico , Abuso de Substâncias por Via Intravenosa/complicaçõesRESUMO
PURPOSE: Leg cramps are common in patients with heart failure. Quinine is frequently prescribed in low doses to these patients, but safety of this practice is unknown. We studied the outcomes associated with use of quinine in a nationwide cohort of patients with heart failure. METHODS: Through individual-level-linkage of Danish national registries, we identified patients discharged from first-time hospitalization for heart failure in 1997-2010. We estimated the risk of mortality associated with quinine treatment by time-dependent Poisson regression models. RESULTS: A total of 135 529 patients were included, with 14 510 patients (11%) using quinine at some point. During a median time of follow-up of 989 days (interquartile range 350-2004) 88 878 patients (66%) died. Patients receiving quinine had slightly increased mortality risk, adjusted incidence rate ratio (IRR) 1.04 (95% confidence interval [CI] 1.01 to 1.07). The risks differed according to concomitant ß-blocker treatment. For patients treated with both quinine and ß-blockers IRR was 1.15 (95% CI 1.09 to 1.21) vs. 0.99 (95% CI 0.96 to 1.03) for patients treated with quinine but not ß-blockers. The risks were highest shortly after initiation of therapy: for the first 14 days of treatment IRR was 2.12 (95% CI 1.54 to 2.93) for patients in treatment with ß-blockers and 1.17 (95% CI 0.86 to 1.59) for patients not treated with ß-blockers. CONCLUSIONS: Use of quinine was common and associated with increased mortality in heart failure, especially if administered together with ß-blockers and shortly after treatment initiation. Mechanisms underlying the findings remain to be established.