Time-course of sFlt-1 and VEGF-A release in neutropenic patients with sepsis and septic shock: a prospective study

<p>Abstract</p> <p>Background</p> <p>Septic shock is the most feared complication of chemotherapy-induced febrile neutropenia. So far, there are no robust biomarkers that can stratify patients to the risk of sepsis complications. The VEGF-A axis is involved in the control of microvascular permeability and has been involved in the pathogenesis of conditions associated with endothelial barrier disruption such as sepsis. sFlt-1 is a soluble variant of the VEGF-A receptor VEGFR-1 that acts as a decoy receptor down-regulating the effects of VEGF-A. In animal models of sepsis, sFlt-1 was capable to block the barrier-breaking negative effects of VEGF-A and to significantly decrease mortality. In non-neutropenic patients, sFlt-1 has been shown to be a promising biomarker for sepsis severity.</p> <p>Methods</p> <p>We prospectively evaluated concentrations of sFlt-1 and VEGF-A at different time-points during febrile neutropenia, and evaluated the association of these levels with sepsis severity and septic shock development.</p> <p>Results</p> <p>Neutropenic patients that evolved with septic shock (n = 10) presented higher levels of sFlt-1 and VEGF-A measured 48 hours after fever onset than patients with non-complicated sepsis (n = 31) and levels of these biomarkers correlated with sepsis severity scores. Estimation of the diagnostic accuracy of sFlt-1 levels for the discrimination of patients that evolved to septic shock yielded promising results in our study population.</p> <p>Discussion</p> <p>Our data suggest that sFlt-1 and VEGF-A could be useful biomarkers for sepsis severity in patients with febrile neutropenia. In addition, the kinetics of sFlt-1 release in patients that evolve to septic shock suggest that the sFlt-1 could be a salvage compensatory mechanism in patients with septic shock, but that the magnitude of the sFlt-1 release observed in human sepsis is not sufficient to reproduce the beneficial anti-VEGF-A effects observed in animal models of sepsis.</p

Evidence of recurrent selection of mutations commonly found in SARS-CoV-2 variants of concern in viruses infecting immunocompromised patients

Chronically immunosuppressed patients infected with SARS-CoV-2 often experience prolonged virus shedding, and may pave the way to the emergence of mutations that render viral variants of concern (VOC) able to escape immune responses induced by natural infection or by vaccination. We report herein a SARS-CoV-2+ cancer patient from the beginning of the COVID-19 pandemic whose virus quasispecies across multiple timepoints carried several immune escape mutations found in more contemporary VOC, such as alpha, delta and omicron, that appeared to be selected for during infection. We hypothesize that immunosuppressed patients may represent the source of VOC seen throughout the COVID-19 pandemics

Imbalances in serum angiopoietin concentrations are early predictors of septic shock development in patients with post chemotherapy febrile neutropenia

Background: Febrile neutropenia carries a high risk of sepsis complications, and the identification of biomarkers capable to identify high risk patients is a great challenge. Angiopoietins (Ang -) are cytokines involved in the control microvascular permeability. It is accepted that Ang-1 expression maintains endothelial barrier integrity, and that Ang-2 acts as an antagonizing cytokine with barrier-disrupting functions in inflammatory situations. Ang-2 levels have been recently correlated with sepsis mortality in intensive care units. Methods: We prospectively evaluated concentrations of Ang-1 and Ang-2 at different time-points during febrile neutropenia, and explored the diagnostic accuracy of these mediators as potential predictors of poor outcome in this clinical setting before the development of sepsis complications. Results: Patients that evolved with septic shock (n = 10) presented higher levels of Ang-2 measured 48 hours after fever onset, and of the Ang-2/Ang-1 ratio at the time of fever onset compared to patients with non-complicated sepsis (n = 31). These levels correlated with sepsis severity scores. Conclusions: Our data suggest that imbalances in the concentrations of Ang-1 and Ang-2 are independent and early markers of the risk of developing septic shock and of sepsis mortality in febrile neutropenia, and larger studies are warranted to validate their clinical usefulness. Therapeutic strategies that manipulate this Ang-2/Ang-1 imbalance can potentially offer new and promising treatments for sepsis in febrile neutropenia

Evaluation of an Antimicrobial L-Amino Acid Oxidase and Peptide Derivatives from Bothropoides mattogrosensis Pitviper Venom

Healthcare-associated infections (HAIs) are causes of mortality and morbidity worldwide. The prevalence of bacterial resistance to common antibiotics has increased in recent years, highlighting the need to develop novel alternatives for controlling these pathogens. Pitviper venoms are composed of a multifaceted mixture of peptides, proteins and inorganic components. L-amino oxidase (LAO) is a multifunctional enzyme that is able to develop different activities including antibacterial activity. In this study a novel LAO from Bothrops mattogrosensis (BmLAO) was isolated and biochemically characterized. Partial enzyme sequence showed full identity to Bothrops pauloensis LAO. Moreover, LAO here isolated showed remarkable antibacterial activity against Gram-positive and -negative bacteria, clearly suggesting a secondary protective function. Otherwise, no cytotoxic activities against macrophages and erythrocytes were observed. Finally, some LAO fragments (BmLAO-f1, BmLAO-f2 and BmLAO-f3) were synthesized and further evaluated, also showing enhanced antimicrobial activity. Peptide fragments, which are the key residues involved in antimicrobial activity, were also structurally studied by using theoretical models. The fragments reported here may be promising candidates in the rational design of new antibiotics that could be used to control resistant microorganisms

Characterization of HIV-1 Near Full-Length Proviral Genome Quasispecies from Patients with Undetectable Viral Load Undergoing First-Line HAART Therapy

Increased access to highly active antiretroviral therapy (HAART) by human immunodeficiency virus postive (HIV+) individuals has become a reality worldwide. In Brazil, HAART currently reaches over half of HIV-infected subjects. In the context of a remarkable HIV-1 genetic variability, highly related variants, called quasispecies, are generated. HIV quasispecies generated during infection can influence virus persistence and pathogenicity, representing a challenge to treatment. However, the clinical relevance of minority quasispecies is still uncertain. In this study, we have determined the archived proviral sequences, viral subtype and drug resistance mutations from a cohort of HIV+ patients with undetectable viral load undergoing HAART as first-line therapy using next-generation sequencing for near full-length virus genome (NFLG) assembly. HIV-1 consensus sequences representing NFLG were obtained for eleven patients, while for another twelve varying genome coverage rates were obtained. Phylogenetic analysis showed the predominance of subtype B (83%; 19/23). Considering the minority variants, 18 patients carried archived virus harboring at least one mutation conferring antiretroviral resistance; for six patients, the mutations correlated with the current ARVs used. These data highlight the importance of monitoring HIV minority drug resistant variants and their clinical impact, to guide future regimen switches and improve HIV treatment success

HIV behind bars: human immunodeficiency virus cluster analysis and drug resistance in a reference correctional unit from southern Brazil.

People deprived of liberty in prisons are at higher risk of infection by the human immunodeficiency virus (HIV) due to their increased exposure through intravenous drug use, unprotected sexual activity, tattooing in prison and blood exposure in fights and rebellions. Yet, the contribution of intramural HIV transmission to the epidemic is scarcely known, especially in low- and middle-income settings. In this study, we surveyed 1,667 inmates incarcerated at Presídio Central de Porto Alegre, located in southern Brazil, for HIV infection and molecular characterization. The HIV seroprevalence was 6.6% (110/1,667). Further analyses were carried out on 40 HIV-seropositive inmates to assess HIV transmission clusters and drug resistance within the facility with the use of molecular and phylogenetic techniques. The molecular epidemiology of HIV-1 subtypes observed was similar to the one reported for the general population in southern Brazil, with the predominance of HIV-1 subtypes C, B, CRF31_BC and unique BC recombinants. In particular, the high rate (24%) of URF_BC found here may reflect multiple exposures of the population investigated to HIV infection. We failed to find HIV-infected inmates sharing transmission clusters with each other. Importantly, the analysis of HIV-1 pol genomic fragments evidenced high rates of HIV primary and secondary (acquired) drug resistance and an alarming proportion of virologic failure among patients under treatment, unveiling suboptimal access to antiretroviral therapy (ARV), low ARV adherence and dissemination of drug resistant HIV strains in primary infections. Our results call for immediate actions of public authority to implement preventive measures, serological screening and, for HIV-seropositive subjects, clinical and treatment follow-up in order to control HIV infection and limit the spread of drug resistance strains in Brazilian prisons

Comparison of four different human papillomavirus genotyping methods in cervical samples: Addressing method-specific advantages and limitations

Since human papillomavirus (HPV) is recognized as the causative agent of cervical cancer and associated with anogenital non-cervical and oropharyngeal cancers, the characterization of the HPV types circulating in different geographic regions is an important tool in screening and prevention. In this context, this study compared four methodologies for HPV detection and genotyping: real-time PCR (Cobas® HPV test), nested PCR followed by conventional Sanger sequencing, reverse hybridization (High + Low PapillomaStrip® kit) and next-generation sequencing (NGS) at an Illumina HiSeq2500 platform. Cervical samples from patients followed at the Family Health Strategy from Juiz de Fora, Minas Gerais, Brazil, were collected and subjected to the real-time PCR. Of those, 114 were included in this study according to the results obtained with the real-time PCR, considered herein as the gold standard method. For the 110 samples tested by at least one methodology in addition to real-time PCR, NGS showed the lowest concordance rates of HPV and high-risk HPV identification compared to the other three methods (67–75 %). Real-time PCR and Sanger sequencing showed the highest rates of concordance (97–100 %). All methods differed in their sensitivity and specificity. HPV genotyping contributes to individual risk stratification, therapeutic decisions, epidemiological studies and vaccine development, supporting approaches in prevention, healthcare and management of HPV infection

Ultra-sensitive detection of Mycobacterium leprae: DNA extraction and PCR assays.

Leprosy urgently needs a precise and early diagnostic tool. The sensitivity of the direct (bacilli staining, Mycobacterium leprae DNA) and indirect (antibody levels, T cell assays) diagnostics methods vary based on the clinical form. Recently, PCR-based M. leprae DNA detection has been shown to differentially diagnose leprosy from other dermatological conditions. However, accuracy can still be improved, especially for use with less invasive clinical samples. We tested different commercial DNA extraction kits: DNeasy Blood & Tissue, QIAamp DNA Microbiome, Maxwell 16 DNA Purification, PowerSoil DNA Isolation; as well as in-house phenol-chloroform and Trizol/FastPrep methods. Extraction was performed on M. leprae-infected mouse footpads and different clinical samples of leprosy patients (skin biopsies and scrapings, lesion, oral and nasal swabs, body hair, blood on FTA cards, peripheral whole blood). We observed that the Microbiome kit was able to enrich for mycobacterial DNA, most likely due the enzymatic digestion cocktail along with mechanical disruption involved in this method. Consequently, we had a significant increase in sensitivity in skin biopsies from paucibacillary leprosy patients using a duplex qPCR targeting 16S rRNA (M. leprae) and 18S rRNA (mammal) in the StepOnePlus system. Our data showed that the presence of M. leprae DNA was best detected in skin biopsies and skin scrapings, independent of the extraction method or the clinical form. For multibacillary patients, detection of M. leprae DNA in nasal swabs indicates the possibility of having a much less invasive sample that can be used for the purposes of DNA sequencing for relapse analysis and drug resistance monitoring. Overall, DNA extracted with the Microbiome kit presented the best bacilli detection rate for paucibacillary cases, indicating that investments in extraction methods with mechanical and DNA digestion should be made