RESUMO
BACKGROUND & AIM: Liver fibrosis is the strongest predictor of liver-related mortality in many chronic liver diseases. NT-ProBNP is independently associated with cardiovascular mortality in general population settings. Here, we evaluate the relative contribution of non-invasively identified liver fibrosis and NT-ProBNP on all-cause and cardiovascular mortality in patients with metabolic (dysfunction)-associated steatotic liver disease (MASLD). METHODS AND RESULTS: Serum NT-ProBNP levels were measured in 4229 patients with MASLD from the general population without a known history of heart failure that participated in the 1999-2004 cycles of the National Health and Nutrition Examination Survey. Presence of liver fibrosis was estimated using the Fibrosis-4 index (FIB-4). We applied Cox proportional hazard models adjusted for cardiovascular risk factors to evaluate the association between NT-ProBNP and FIB-4 levels and all-cause and cardiovascular mortality through December 2019. Mortality was lower for participants with normal levels of both biomarkers, intermediate if a single biomarker was elevated and highest when both were above the chosen threshold. In the multivariable-adjusted models, both elevated FIB-4 (≥2.67) and elevated NT-ProBNP levels (≥125 pg/ml) were independently associated with higher risks of all-cause mortality (HR 2.2, 95 % CI 1.5-3.2 and HR 1.6, 95 % CI 1.4-2.0, respectively) and cardiovascular mortality (HR 2.1, 95 % CI 1.2-3.7 and HR 2.1, 95 % CI 1.5-2.9, respectively). The associations remained consistent in subgroup analyses based on sex, obesity and age. CONCLUSIONS: Both FIB-4 and NT-ProBNP are independently associated with higher mortality in patients with MASLD. Their combined use might prove useful to risk-stratify patients in clinical practice.
Assuntos
Insuficiência Cardíaca , Peptídeo Natriurético Encefálico , Humanos , Prognóstico , Estudos de Coortes , Inquéritos Nutricionais , Biomarcadores , Fragmentos de Peptídeos , Cirrose Hepática/diagnósticoRESUMO
BACKGROUND AND AIMS: Several studies reported an association between liver stiffness measurement (LSM) obtained through vibration-controlled transient elastography (VCTE) and all-cause mortality in patients with nonalcoholic fatty liver disease (NAFLD). The objective of this systematic review and meta-analysis was to summarize available evidence on the nature and magnitude of this association. METHODS: We systematically searched PubMed-MEDLINE and Scopus up to April 2023 for observational cohort studies in which LSM was measured with VCTE in patients with NAFLD or in general population settings, with a follow-up ≥1 year and with available data on all-cause mortality. Measures of association from individual studies were meta-analysed using random effects models. Of the 517 titles initially scrutinized, we included seven studies with data on 18 771 participants (47.1% male) and a mean follow-up of 3.6 years. We included effect estimates obtained in the models with the highest degree of adjustment for potential confounders available in each study. RESULTS: When analysed as a categorical variable based on specific LSM cut-offs, liver fibrosis was associated with an increased risk of all-cause death (HR 2.10, 95% CI 1.56-2.83; test for overall effect z = 4.919, p < 0.001). Results were consistent when LSM was considered as a continuous variable (HR for 1 kPa increase: 1.03, 95% CI 1.01-1.05; test for overall effect z = 3.341, p = 0.001). There was borderline significant heterogeneity among the studies (I2 = 50.2% and I2 = 66.7% in the two analyses, respectively). No significant publication bias was detected by funnel plot analysis and Egger's and Begg's tests. CONCLUSION: The present meta-analysis indicates that LSM, as a proxy of liver fibrosis, is independently and directly associated with a higher mortality risk in patients with NAFLD.
Assuntos
Técnicas de Imagem por Elasticidade , Hepatopatia Gordurosa não Alcoólica , Humanos , Masculino , Feminino , Hepatopatia Gordurosa não Alcoólica/epidemiologia , Cirrose Hepática/complicações , Técnicas de Imagem por Elasticidade/métodos , Fígado/diagnóstico por imagem , Fígado/patologiaRESUMO
BACKGROUND: Even though hyperglycemia is a well-known cardiovascular risk factor, the absolute risk of cardiovascular events varies to a great extent within each glycemic category. The aim of this study is to evaluate whether N-terminal pro-B natriuretic peptide (NT-ProBNP) could help identify subjects at higher cardiovascular risk, independently of blood glucose levels. METHODS: Serum NT-ProBNP levels were measured in 5502 people aged 45-79 years without heart failure from the general population (3380 with normoglycemia, 1125 with pre-diabetes and 997 with diabetes) that participated in the 1999-2004 cycles of the National Health and Nutrition Examination Survey. We applied Cox and Fine Gray models adjusted for cardiovascular risk factors to evaluate the association between NT-ProBNP levels and all-cause and cardiovascular mortality through December 2015. RESULTS: After a median follow-up of 13 years, 1509 participants died, 330 of cardiovascular causes. In the multivariable-adjusted models, compared with participants with NT-ProBNP < 100 pg/ml, those with levels 100-300 pg/ml and ≥ 300 pg/ml had a higher incidence of both all-cause mortality (HR 1.61, 95% CI 1.12-2.32, p = 0.012 and HR 2.96, 95% CI 1.75-5.00, p < 0.001, respectively) and cardiovascular mortality (HR 1.57, 95% CI 1.17-2.10, p = 0.011 and HR 2.08, 95% CI 1.47-2.93, p < 0.001, respectively). The association was consistent in subgroup analyses based on glycemic status, obesity, age and sex. CONCLUSIONS: Elevated NT-ProBNP is independently associated with all-cause and cardiovascular mortality in the general population and could help identify patients at the highest risk. Further studies are needed to evaluate whether intensification of treatment based on biomarker data might lead to improvements in cardiovascular risk reduction.
Assuntos
Insuficiência Cardíaca , Peptídeo Natriurético Encefálico , Humanos , Inquéritos Nutricionais , Prognóstico , Medição de Risco , Fragmentos de Peptídeos , Biomarcadores , GlucoseRESUMO
Bacterial outer membrane vesicles (OMVs) represent an interesting vaccine platform for their built-in adjuvanticity and simplicity of production process. Moreover, OMVs can be decorated with foreign antigens using different synthetic biology approaches. However, the optimal OMV engineering strategy, which should guarantee the OMV compartmentalization of most heterologous antigens in quantities high enough to elicit protective immune responses, remains to be validated. In this work we exploited the lipoprotein transport pathway to engineer OMVs with foreign proteins. Using 5 Staphylococcus aureus protective antigens expressed in Escherichia coli as fusions to a lipoprotein leader sequence, we demonstrated that all 5 antigens accumulated in the vesicular compartment at a concentration ranging from 5 to 20% of total OMV proteins, suggesting that antigen lipidation could be a universal approach for OMV manipulation. Engineered OMVs elicited high, saturating antigen-specific antibody titers when administered to mice in quantities as low as 0.2 µg/dose. Moreover, the expression of lipidated antigens in E. coli BL21(DE3)ΔompAΔmsbBΔpagP was shown to affect the lipopolysaccharide structure, with the result that the TLR4 agonist activity of OMVs was markedly reduced. These results, together with the potent protective activity of engineered OMVs observed in mice challenged with S. aureus Newman strain, makes the 5-combo-OMVs a promising vaccine candidate to be tested in clinics.
Assuntos
Antígenos de Bactérias/imunologia , Vacinas Bacterianas/imunologia , Vesículas Extracelulares/imunologia , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/imunologia , Animais , Membrana Externa Bacteriana/imunologia , Membrana Externa Bacteriana/metabolismo , Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas da Membrana Bacteriana Externa/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Feminino , Lipopolissacarídeos/imunologia , Camundongos , Infecções Estafilocócicas/imunologia , Infecções Estafilocócicas/microbiologiaRESUMO
BACKGROUND: Bariatric surgery is a valuable therapeutic option in the treatment of obesity but the outcomes show a large subject-to-subject variability yet to be explained. Thyroid function may represent an involved factor and we have only few controversial data about its influence. SUBJECTS/METHODS: We retrospectively assessed using a longitudinal approach the relation between baseline TSH levels and short-term (6 and 12 months) weight loss in 387 euthyroid patients who underwent laparoscopic gastric banding (LAGB; n = 187) or sleeve gastrectomy (SG; n = 200). RESULTS: After LAGB, patients with low-normal TSH levels (0.40-1.40 mUI/L) had higher percent total weight loss, ∆BMI and percent excess weight loss when compared to patients with normal (1.41-2.48 mUI/L) and high-normal (2.49-4.00 mUI/L) TSH (p < 0.05). Conversely, no association was detected after SG (p = 0.17). The multivariable regression analysis showed that also baseline BMI (6-12 months) and HOMA2-IR (only at 6 months) were independently associated with the outcomes. CONCLUSIONS: TSH levels may influence the short-term weight loss response after LAGB. The lack of association after SG suggests that the influence of baseline endocrine and metabolic factors may not be relevant for procedures with greater and more immediate calorie intake restriction.
Assuntos
Cirurgia Bariátrica/efeitos adversos , Cirurgia Bariátrica/métodos , Gastrectomia/efeitos adversos , Gastrectomia/métodos , Obesidade/cirurgia , Tireotropina/sangue , Índice de Massa Corporal , Feminino , Humanos , Laparoscopia , Estudos Longitudinais , Masculino , Análise de Regressão , Estudos Retrospectivos , Resultado do Tratamento , Redução de PesoRESUMO
AIMS: Hypothalamus-pituitary-adrenal (HPA) axis hyperactivity was suggested to be associated with the metabolic syndrome (MS), obesity and diabetes. The aim of this study was to test whether hypercortisolism was associated with altered glucose homeostasis and insulin resistance, hypertension and dyslipidemia in a homogeneous population of obese patients. MATERIALS/METHODS: In retrospective analysis of a set of data about obese patients attending the outpatient service of a single obesity centre between January 2013 and January 2020, 884 patients with BMI >30 kg/m2 were segregated in two subgroups: patients with urinary free cortisol (UFC) higher than normal (UFC+; n = 129) or within the normal range (UFC-; n = 755). RESULTS: The overall prevalence of UFC+ was 14.6% and double test positivity (morning cortisol >1.8 mcg/dL following overnight dexamethasone suppression test, ODST) was detected in 1.0% of patients. Prediabetes (OR 1.74; 95%CI 1.13-2.69; p = 0.012) and diabetes (OR 2.03; 95%CI 1.21-3.42; p = 0.008) were associated with higher risk of UFC+ when analysis was adjusted for confounding variables. Conversely, hypertension and dyslipidemia were not related to UFC+. Within the individuals with normal FPG and HbA1c, those with higher estimated insulin resistance (HOMA2-IR) maintained a higher risk of UFC+ (OR 2.84, 95%CI 1.06-7.63; p = 0.039) and this relationship was weakened only when the body fat percentage was included into the model. CONCLUSIONS: In obese patients, hypercortisolism was more frequent across the entire spectrum of altered glucose homeostasis including the very early stages; this relation could not be detected for the other criteria of the MS, as waist, hypertension and atherogenic dyslipidemia.
Assuntos
Síndrome de Cushing , Glucose , Homeostase , Obesidade , Cirurgia Bariátrica , Síndrome de Cushing/complicações , Glucose/metabolismo , Homeostase/fisiologia , Humanos , Obesidade/fisiopatologia , Obesidade/cirurgia , Estudos RetrospectivosRESUMO
BACKGROUND AND AIMS: Seasonal variations in several risk factors for cardiovascular events (CVD) were described. Here, we evaluate the impact of seasonal variations in blood pressure (BP), lipid profile and glycemic control on estimated CVD risk in patients with type 2 diabetes (T2D). METHODS AND RESULTS: Retrospective monocentric study of patients with T2D who were visited at least once in the winter period and once in the summer period, less than 8 months apart, for which data related to systolic (S) BP, diastolic (D) BP, body mass index, glycosylated hemoglobin (HbA1c), total cholesterol, HDL cholesterol and smoking habit were available on both occasions. The 10-year CVD risk was calculated using the UKPDS risk engine and the ASCVD risk estimator. As many as 411 patients were included in the study. Significant within-patient differences between summer and winter were found for the absolute risk of events assessed with both calculators (Δs-w UKPDS-CHD: -1.33%, Δs-w UKPDS-Stroke: -0.84%, Δs-w ASCVD: -2.21%). The seasonal change in SBP was the main responsible for the change in risk estimated with both the UKPDS-Stroke (r2 = 0.43) and the ASCVD (r2 = 0.50) scores, while the change in total cholesterol was the main determinant of the change in risk for the UKPDS-CHD (r2 = 0.34). A significant correlation was identified between changes in temperature and changes in SBP (ρ = 0.130, p = 0.008), but not in other risk factors. CONCLUSIONS: Seasonal variations in the classic CVD risk factors influence the risk estimated using validated calculators.
Assuntos
Doenças Cardiovasculares/epidemiologia , Diabetes Mellitus Tipo 2/epidemiologia , Estações do Ano , Idoso , Doenças Cardiovasculares/diagnóstico , Comorbidade , Diabetes Mellitus Tipo 2/diagnóstico , Feminino , Fatores de Risco de Doenças Cardíacas , Humanos , Itália/epidemiologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Medição de Risco , Temperatura , Fatores de TempoRESUMO
In Gram-negative bacteria, outer membrane-associated lipoproteins can either face the periplasm or protrude out of the bacterial surface. The mechanisms involved in lipoprotein transport through the outer membrane are not fully elucidated. Some lipoproteins reach the surface by using species-specific transport machinery. By contrast, a still poorly characterized group of lipoproteins appears to always cross the outer membrane, even when transplanted from one organism to another. To investigate such lipoproteins, we tested the expression and compartmentalization in E. coli of three surface-exposed lipoproteins, two from Neisseria meningitidis (Nm-fHbp and NHBA) and one from Aggregatibacter actinomycetemcomitans (Aa-fHbp). We found that all three lipoproteins were lipidated and compartmentalized in the E. coli outer membrane and in outer membrane vesicles. Furthermore, fluorescent antibody cell sorting analysis, proteolytic surface shaving, and confocal microscopy revealed that all three proteins were also exposed on the surface of the outer membrane. Removal or substitution of the first four amino acids following the lipidated cysteine residue and extensive deletions of the C-terminal regions in Nm-fHbp did not prevent the protein from reaching the surface of the outer membrane. Heterologous polypeptides, fused to the C termini of Nm-fHbp and NHBA, were efficiently transported to the E. coli cell surface and compartmentalized in outer membrane vesicles, demonstrating that these lipoproteins can be exploited in biotechnological applications requiring Gram-negative bacterial surface display of foreign polypeptides.
Assuntos
Aggregatibacter actinomycetemcomitans/metabolismo , Escherichia coli/genética , Lipoproteínas/metabolismo , Neisseria meningitidis/metabolismo , Aggregatibacter actinomycetemcomitans/genética , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/metabolismo , Membrana Celular/metabolismo , Escherichia coli/citologia , Escherichia coli/metabolismo , Lipoproteínas/genética , Neisseria meningitidis/genética , Transporte Proteico , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Transformação BacterianaRESUMO
BACKGROUND: The exploitation of the CRISPR/Cas9 machinery coupled to lambda (λ) recombinase-mediated homologous recombination (recombineering) is becoming the method of choice for genome editing in E. coli. First proposed by Jiang and co-workers, the strategy has been subsequently fine-tuned by several authors who demonstrated, by using few selected loci, that the efficiency of mutagenesis (number of mutant colonies over total number of colonies analyzed) can be extremely high (up to 100%). However, from published data it is difficult to appreciate the robustness of the technology, defined as the number of successfully mutated loci over the total number of targeted loci. This information is particularly relevant in high-throughput genome editing, where repetition of experiments to rescue missing mutants would be impractical. This work describes a "brute force" validation activity, which culminated in the definition of a robust, simple and rapid protocol for single or multiple gene deletions. RESULTS: We first set up our own version of the CRISPR/Cas9 protocol and then we evaluated the mutagenesis efficiency by changing different parameters including sequence of guide RNAs, length and concentration of donor DNAs, and use of single stranded and double stranded donor DNAs. We then validated the optimized conditions targeting 78 "dispensable" genes. This work led to the definition of a protocol, featuring the use of double stranded synthetic donor DNAs, which guarantees mutagenesis efficiencies consistently higher than 10% and a robustness of 100%. The procedure can be applied also for simultaneous gene deletions. CONCLUSIONS: This work defines for the first time the robustness of a CRISPR/Cas9-based protocol based on a large sample size. Since the technical solutions here proposed can be applied to other similar procedures, the data could be of general interest for the scientific community working on bacterial genome editing and, in particular, for those involved in synthetic biology projects requiring high throughput procedures.
Assuntos
Sistemas CRISPR-Cas , Escherichia coli/genética , Edição de Genes , Família Multigênica , Deleção de Genes , Genoma Bacteriano , Recombinação Homóloga , Mutagênese , RNA Guia de Cinetoplastídeos , Recombinases/metabolismo , Biologia Sintética/métodosRESUMO
OBJECTIVE: The outcome of antithyroid drug (ATD) treatment for Graves disease (GD) is difficult to predict. In this study, we investigated whether male gender, besides other factors usually associated with a poor outcome of ATD treatment, may affect disease presentation and predict the response to medical treatment in subjects with GD. METHODS: We studied 294 patients with a first diagnosis of GD. In all patients, ATD treatment was started. Clinical features, thyroid volume, and eye involvement were recorded at baseline. Serum levels of free thyroxine (FT4), free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), and TSH-receptor antibodies (TRAb) were measured at baseline and during the follow-up. Treatment outcome (FT4, FT3, and TSH serum levels and further treatments for GD after ATD withdrawal) was evaluated. RESULTS: When compared to women, men showed a significantly larger thyroid volume and a higher family positivity for autoimmune diseases. During ATD, the mean serum levels of TSH, FT4, FT3, and TRAb did not differ between groups. Within 1 year after ATD discontinuation, relapse of hyperthyroidism was significantly more frequent in men than in women. Within the 5-year follow-up period, the prevalence of men suffering a late relapse was higher compared with that of women. The outcome at the end of the 5-year follow-up period was significantly associated with gender and TRAb levels at disease onset. CONCLUSION: Male patients with GD have a poorer prognosis when submitted to medical treatment with ATDs. A larger goiter at presentation and a stronger genetic autoimmune background might explain this gender difference in patients with GD. ABBREVIATIONS: ATD = antithyroid drug FT3 = free triiodothyronine FT4 = free thyroxine GD = Graves disease GO = Graves orbitopathy RAI = radioiodine TRAb = thyroid-stimulating hormone-receptor antibody TSH = thyroid-stimulating hormone.
Assuntos
Antitireóideos/farmacologia , Doença de Graves/sangue , Doença de Graves/tratamento farmacológico , Doença de Graves/fisiopatologia , Avaliação de Resultados em Cuidados de Saúde , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antitireóideos/administração & dosagem , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Recidiva , Fatores Sexuais , Adulto JovemRESUMO
BACKGROUND: Protocols of controlled ovarian hyper-stimulation (COH) require, as a crucial step, the identification of reliable predictors of ovarian reserve. Anti-Mullerian hormone (AMH) is one of the most reliable predictors of ovarian reserve but other factors including autoimmune thyroid diseases (ATD) have been associated with reduced fertility and poor COH outcome. Aim of the present study was to evaluate the relationship between ATD and AMH, and their role on the outcome of COH. METHODS: The study group included 288 sub-fertile euthyroid women aged less than 40 years attending a single center for Reproductive Medicine. Among them, 55 were ATD-positive and 233 ATD-negative. The serum levels of AMH, FSH, LH, estradiol (E2), and TSH were measured before COH. The ratio between serum E2 concentration on the day of oocytes pick-up and the total dose of administered recombinant FSH (r-FSH) (E2/r-FSH ratio) was calculated. RESULTS: The serum levels of AMH were significantly related to E2/r-FSH ratio, total dose of r-FSH and number of M II oocytes, both in ATD-positive and ATD-negative women. Within the low stratum of AMH levels, the presence of ATD did not further affect the outcome of COH. When the serum levels of AMH were in the high stratum, the presence of ATD significantly affected the E2/rFSH ratio, the total dose of r-FSH and the number of M II oocytes. CONCLUSIONS: The probability of a poor response to COH is high, and independent from ATD, in women with low AMH serum levels. In women with a good ovarian reserve, as assessed by high AMH serum levels, the presence of ATD impairs the outcome of COH.
Assuntos
Hormônio Antimülleriano/sangue , Doenças Autoimunes/sangue , Autoimunidade/imunologia , Infertilidade Feminina/sangue , Reserva Ovariana/fisiologia , Indução da Ovulação/métodos , Glândula Tireoide/imunologia , Adulto , Doenças Autoimunes/complicações , Doenças Autoimunes/imunologia , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Humanos , Infertilidade Feminina/complicações , Infertilidade Feminina/terapia , Hormônio Luteinizante/sangue , Técnicas de Reprodução Assistida , Estudos Retrospectivos , Tireotropina/sangueRESUMO
OBJECTIVE: The aim of the study was to evaluate the diagnostic performance of a new ultrasound elastography (USE) parameter based on the measurement of the percentage of maximal stiffness within a nodule as compared with the already established elastographic strain index (SI) and to investigate their diagnostic performance according to nodule size. METHODS: The study included 218 nodules. Each nodule underwent conventional ultrasound (US), USE evaluation, and fine-needle aspiration cytology (FNAC). Thyroid nodules were further stratified into 4 subgroups (G) according to their size (G1, <1 cm; G2, 1-2 cm; G3, >3 cm). USE evaluation comprised the measurement of the percentage of the areas included in the region of interest corresponding to the maximal stiffness (% Index) and of the SI. RESULTS: The % Index and of the SI were significantly higher in malignant than in benign thyroid nodules, and both measurements displayed a good diagnostic performance (SI sensitivity and specificity, 0.66 and 0.90, respectively; % Index sensitivity and specificity, 0.76 and 0.89, respectively). Compared with SI, the % Index was more informative, both in the whole group of thyroid nodules (odds ratio [OR], 18.68; 95% confidence interval [CI], 6.06 to 63.49; P<.0001 versus OR, 26.15; 95% CI, 8.01 to 102.87; P<.0001, respectively) and in the G1 and G2 subgroups. CONCLUSION: The % Index is a stronger predictor of nodule malignancy than both the SI and the conventional US signs. This is particularly true in nodules smaller than 1 cm, which are more difficult to explore both by conventional US and FNAC.
Assuntos
Técnicas de Imagem por Elasticidade/métodos , Nódulo da Glândula Tireoide/diagnóstico por imagem , Ultrassonografia/métodos , Adulto , Fenômenos Biomecânicos , Biópsia por Agulha Fina , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Sensibilidade e Especificidade , Nódulo da Glândula Tireoide/patologiaRESUMO
Gram-positive bacteria build pili on their cell surface via a class C sortase-catalyzed transpeptidation mechanism from pilin protein substrates. Despite the availability of several crystal structures, pilus-related C sortases remain poorly characterized to date, and their mechanisms of transpeptidation and regulation need to be further investigated. The available 3-dimensional structures of these enzymes reveal a typical sortase fold, except for the presence of a unique feature represented by an N-terminal highly flexible loop known as the "lid." This region interacts with the residues composing the catalytic triad and covers the active site, thus maintaining the enzyme in an autoinhibited state and preventing the accessibility to the substrate. It is believed that enzyme activation may occur only after lid displacement from the catalytic domain. In this work, we provide the first direct evidence of the regulatory role of the lid, demonstrating that it is possible to obtain in vitro an efficient polymerization of pilin subunits using an active C sortase lid mutant carrying a single residue mutation in the lid region. Moreover, biochemical analyses of this recombinant mutant reveal that the lid confers thermodynamic and proteolytic stability to the enzyme.
Assuntos
Aminoaciltransferases/metabolismo , Proteínas de Bactérias/metabolismo , Cisteína Endopeptidases/metabolismo , Fímbrias Bacterianas/enzimologia , Streptococcus agalactiae/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Aminoaciltransferases/química , Aminoaciltransferases/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Biocatálise , Western Blotting , Domínio Catalítico , Cisteína Endopeptidases/química , Cisteína Endopeptidases/genética , Proteínas de Fímbrias/genética , Proteínas de Fímbrias/metabolismo , Fluorometria , Cinética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Mutação , Filogenia , Polimerização , Dobramento de Proteína , Estrutura Terciária de Proteína , Proteólise , Streptococcus agalactiae/genéticaRESUMO
Group B Streptococcus pili are covalently linked structures assembled via a sortase-catalyzed transpeptidation mechanism involving specific residues and motifs. A sequence element containing a conserved glutamic acid, called the E-box, has been described to be involved in pilus formation. Although it is known that the glutamic acid is involved in stabilizing the internal isopeptide bonds, its role in pilus assembly still needs to be investigated. Using site-specific mutagenesis and complementation studies of knockout strains, we found that the E-box glutamic residue of the backbone and the major ancillary proteins is essential for pilus protein polymerization. NMR analysis revealed that the mutation of this residue seriously affected the folding of the protein. By contrast, the mutation of the lysine involved in the same isopeptide bond did not engender a structural destabilization, and the native fold was preserved. Moreover, molecular dynamics simulations on the E-box-containing domain of the backbone protein showed that the E-box glutamic acid is necessary to maintain the appropriate dryness of the domain core and that its mutation favors an unfolded state. The data provide the first direct evidence that the E-box has an additional and key role in maintaining the correct protein fold independently of isopeptide bond formation.
Assuntos
Fímbrias Bacterianas/fisiologia , Ácido Glutâmico/fisiologia , Streptococcus agalactiae/fisiologia , Western Blotting , Simulação de Dinâmica Molecular , Ressonância Magnética Nuclear BiomolecularRESUMO
OBJECTIVES: Experimental evidences indicate that leptin is involved in the neuroinflammatory process sustaining multiple sclerosis (MS). However, the relationship between leptin and body fat, as assessed by body mass index (BMI), in MS was not previously evaluated. It was the aim of this study to compare serum leptin levels between patients with MS and healthy controls and to evaluate the possible relationship between circulating leptin levels and disease severity. PATIENTS AND METHODS: Eighty-four MS patients and 57 sex-matched healthy volunteers were enrolled. Serum leptin levels were measured in all patients and controls. MS patients were stratified in 3 groups according to their degree of disability as assessed by the Expanded Disability Status Scale (EDSS). Patients were classified as having low (33 patients with an EDSS score <1.5), intermediate (28 patients with an EDSS score from 2 to 3) and high disability (23 patients with an EDSS score ≥3.5). RESULTS: No significant differences in serum leptin levels and BMI were observed between patients and controls. In patients with MS, serum leptin levels were significantly correlated with BMI in those patients with low (R(2) = 0.363; p < 0.001) and intermediate disability (R(2) = 0.408; p < 0.001), but not in patients with a higher disability score (R(2) = 0.064; p = 0.256). CONCLUSION: BMI, the major determinant of leptin level in physiological conditions, has a minor role in determining the serum levels of leptin in MS patients with a high EDSS score. Future longitudinal studies will be required in order to provide further insights into the regulation of leptin secretion in patients with MS.
Assuntos
Leptina/metabolismo , Esclerose Múltipla Recidivante-Remitente/sangue , Adolescente , Adulto , Idoso , Índice de Massa Corporal , Avaliação da Deficiência , Feminino , Humanos , Leptina/sangue , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla Recidivante-Remitente/complicações , Índice de Gravidade de Doença , Adulto JovemRESUMO
MicroRNAs are small non-coding RNAs that modulate gene expression at post-transcriptional level, playing a crucial role in cell differentiation and development. Recently, some reports have shown that a limited number of mammalian microRNAs are also involved in anti-viral defense. In this study, the analysis of the hepatitis B virus (HBV) genome by the computer program MiRanda led to the identification of seven sites that are potential targets for human liver microRNAs. These sites were found to be clustered in a 995-bp segment within the viral polymerase ORF and the overlapping surface antigen ORF, and conserved among the most common HBV subtypes. The HBV genomic targets were then subjected to a validation test based on cultured hepatic cells (HepG2, HuH-7 and PLC/PRF/5) and luciferase reporter genes. In this test, one of the selected microRNAs, hsa-miR-125a-5p, was found to interact with the viral sequence and to suppress the reporter activity markedly. The microRNA was then shown to interfere with the viral translation, down-regulating the expression of the surface antigen. Overall, these results support the emerging concept that some mammalian microRNAs play a role in virus-host interaction. Furthermore, they provide the basis for the development of new strategies for anti-HBV intervention.
Assuntos
Antígenos de Superfície da Hepatite B/genética , Vírus da Hepatite B/genética , MicroRNAs/metabolismo , Interferência de RNA , Linhagem Celular Tumoral , Genoma Viral , Antígenos de Superfície da Hepatite B/biossíntese , Humanos , Fígado/metabolismo , Biossíntese de ProteínasRESUMO
CONTEXT: Serum neurofilament light chain (sNfL) levels are biomarkers of neuroaxonal injury in multiple neurological diseases. OBJECTIVE: Given the paucity of data on the distribution of sNfL levels in the general population, in the present study we identified predictors of sNfL levels in a community setting and investigated the association between diabetes and sNfL. METHODS: sNfL levels were measured in 2070 people aged 20 to 75 years from the general US population (275 with and 1795 without diabetes) that participated in the 2013-2014 cycle of the National Health and Nutrition Examination Survey. We evaluated the association between diabetes and sNfL levels after adjustment for age, sex, race-ethnicity, alcohol use, and kidney function using a multivariable linear regression model. Cognitive function was evaluated in a subset of participants aged 60 to 75 years using the Consortium to Establish a Registry for Alzheimer's Disease-Word Learning test, the Animal Fluency test, and the Digit Symbol Substitution test. RESULTS: The weighted prevalence of diabetes was 10.4% (95% CI, 9.0-11.9). In each age stratum, patients with diabetes exhibited higher sNfL levels compared with nondiabetic participants. Age, proportion of males, prevalence of diabetes, and homeostatic model of insulin resistance increased progressively across quartiles of sNfL levels in the overall population, whereas estimated glomerular filtration rate (eGFR) showed an opposite trend. In the multivariable model, age, sex, eGFR, alcohol use and diabetes were significantly associated with sNfL levels. Moreover, higher sNfL levels were associated with worse performance in all 3 cognitive function tests. CONCLUSION: Diabetes is associated with higher sNfL. Further large-scale and prospective studies are needed to replicate our results and evaluate the ability of sNfL to predict the incidence of neuropathy and dementia in this patient population.
Assuntos
Diabetes Mellitus , Esclerose Múltipla , Doenças do Sistema Nervoso Periférico , Masculino , Humanos , Filamentos Intermediários , Inquéritos Nutricionais , Biomarcadores , Diabetes Mellitus/epidemiologiaRESUMO
Sex hormones impact body composition. Data on the specific impact of each hormone on different body depots in men and women are scarce. The aim of this study is to evaluate the association between testosterone, estradiol and body fat distribution in the general population. This is a population-based cross-sectional study based on data from the 2013-2016 cycles of the National Health and Nutrition Examination Survey. Dual energy X-ray absorptiometry (DXA) and liquid chromatography tandem mass spectrometry were performed on participants aged 18-59 years to evaluate body composition and sex hormone levels, respectively. Weighted multivariable linear regression analyses were performed to evaluate the association between these parameters after adjustment for potential confounders. A total of 6655 participants (3309 males and 3346 females) was included in the analysis. Men with lower testosterone levels were older, had a higher body mass index (BMI) and had a generally unfavorable metabolic profile, while no specific trends were found in women. Among men, testosterone was positively associated with lean body mass and was negatively associated with fat mass and the android/gynoid (A/G) ratio, while an opposite trend was found for estradiol. Among women, testosterone did not impact body composition, while estradiol levels were positively associated with lean mass and were negatively associated with fat mass. Our results support the notion that the impact of different sex hormones on specific fat depots varies substantially between men and women.
RESUMO
INTRODUCTION: Serum neurofilament light chain (sNfL) levels are biomarkers of neuro-axonal injury in multiple neurological diseases. Little is known on their potential role as prognostic markers in people without known neurological conditions. OBJECTIVE: The aim of this study is to evaluate the association between sNfL levels and all-cause mortality in a general population setting. METHODS: sNfL levels were measured in 2071 people aged 25-75 years from the general US population that participated in the 2013-2014 cycles of the National Health and Nutrition Examination Survey (NHANES). Cognitive function was evaluated in a subset of participants aged 60-75 years using the Consortium to Establish a Registry for Alzheimer's Disease-Word Learning test, the Animal Fluency test and the Digit Symbol Substitution test. We applied Cox proportional hazard models adjusted for several potential confounders to evaluate the association between sNfL and all-cause mortality through December 2019 by linking NHANES data with data from the National Death Index. RESULTS: In a cross-sectional analysis, higher sNfL levels were associated with worse performance in all three cognitive function tests. Over a median follow-up of 6.1 years, 85 participants died. In a multivariable model adjusted for age, sex, race-ethnicity, diabetes, chronic kidney disease, harmful alcohol consumption, cigarette smoke and prevalent cardiovascular disease, higher sNfL levels were significantly and positively associated with all-cause mortality (HR per unit increase in log-transformed sNfL: 2.46, 95% CI 1.77-3.43, p < 0.001). Results were robust when analyses were stratified according to age, sex, body mass index and kidney function. CONCLUSION: We found a positive association between sNfL levels and mortality in the general US population. Further studies are needed to understand the biological mechanisms underlying this association.
Assuntos
Filamentos Intermediários , Proteínas de Neurofilamentos , Humanos , Inquéritos Nutricionais , Estudos Transversais , BiomarcadoresRESUMO
AIM: To investigate the relative contribution of previous gestational diabetes mellitus (GDM) and current type 2 diabetes (T2D) on the development of liver fibrosis, the strongest predictor of end-stage liver disease. METHODS: This is a population-based cross-sectional study based on data from the 2017-2018 cycle of the National Health and Nutrition Examination Survey. We included women age ≥ 20 years that had delivered at least one live birth and had available data on vibration-controlled transient elastography (VCTE). Liver steatosis and fibrosis were assessed by the median value of controlled attenuation parameter (CAP) and liver stiffness measurement (LSM), respectively. RESULTS: Among the 1699 women included in the study, 144 (10.1%, 95% CI 7.7-13.2) reported a previous diagnosis of GDM. Women with previous GDM were younger, had a higher BMI, a higher prevalence of T2D and were significantly older at the time they had the last live birth. Univariate analysis did not show a significant difference between women with and without a prior history of GDM in terms of both steatosis (44.8% vs 39.4%, p = 0.464) and fibrosis (7.5% vs 7.6%, p = 0.854). Multivariable logistic regression analysis showed that BMI, γ-glutamyltranspeptidase levels, T2D (OR 2.96, 95% CI 1.48-5.93, p < 0.01), HBV and HCV infection were associated with higher odds of significant fibrosis, while previous GDM showed a neutral effect. CONCLUSIONS: Women with previous GDM that do not develop overt T2D might not experience a poor hepatic prognosis.