Dilation of ion selectivity filters in cation channels.

Ion channels establish the voltage gradient across cellular membranes by providing aqueous pathways for ions to selectively diffuse down their concentration gradients. The selectivity of any given channel for its favored ions has conventionally been viewed as a stable property, and in many cation channels, it is determined by an ion-selectivity filter within the external end of the ion-permeation pathway. In several instances, including voltage-activated K+ (Kv) channels, ATP-activated P2X receptor channels, and transient receptor potential (TRP) channels, the ion-permeation pathways have been proposed to dilate in response to persistent activation, dynamically altering ion permeation. Here, we discuss evidence for dynamic ion selectivity, examples where ion selectivity filters exhibit structural plasticity, and opportunities to fill gaps in our current understanding.

Clustering COVID-19 ARDS patients through the first days of ICU admission. An analysis of the CIBERESUCICOVID Cohort.

BACKGROUND: Acute respiratory distress syndrome (ARDS) can be classified into sub-phenotypes according to different inflammatory/clinical status. Prognostic enrichment was achieved by grouping patients into hypoinflammatory or hyperinflammatory sub-phenotypes, even though the time of analysis may change the classification according to treatment response or disease evolution. We aimed to evaluate when patients can be clustered in more than 1 group, and how they may change the clustering of patients using data of baseline or day 3, and the prognosis of patients according to their evolution by changing or not the cluster. METHODS: Multicenter, observational prospective, and retrospective study of patients admitted due to ARDS related to COVID-19 infection in Spain. Patients were grouped according to a clustering mixed-type data algorithm (k-prototypes) using continuous and categorical readily available variables at baseline and day 3. RESULTS: Of 6205 patients, 3743 (60%) were included in the study. According to silhouette analysis, patients were grouped in two clusters. At baseline, 1402 (37%) patients were included in cluster 1 and 2341(63%) in cluster 2. On day 3, 1557(42%) patients were included in cluster 1 and 2086 (57%) in cluster 2. The patients included in cluster 2 were older and more frequently hypertensive and had a higher prevalence of shock, organ dysfunction, inflammatory biomarkers, and worst respiratory indexes at both time points. The 90-day mortality was higher in cluster 2 at both clustering processes (43.8% [n = 1025] versus 27.3% [n = 383] at baseline, and 49% [n = 1023] versus 20.6% [n = 321] on day 3). Four hundred and fifty-eight (33%) patients clustered in the first group were clustered in the second group on day 3. In contrast, 638 (27%) patients clustered in the second group were clustered in the first group on day 3. CONCLUSIONS: During the first days, patients can be clustered into two groups and the process of clustering patients may change as they continue to evolve. This means that despite a vast majority of patients remaining in the same cluster, a minority reaching 33% of patients analyzed may be re-categorized into different clusters based on their progress. Such changes can significantly impact their prognosis.

Eukaryotic Kv channel Shaker inactivates through selectivity filter dilation rather than collapse.

Eukaryotic voltage-gated K+ channels have been extensively studied, but the structural bases for some of their most salient functional features remain to be established. C-type inactivation, for example, is an auto-inhibitory mechanism that confers temporal resolution to their signal-firing activity. In a recent breakthrough, studies of a mutant of Shaker that is prone to inactivate indicated that this process entails a dilation of the selectivity filter, the narrowest part of the ion conduction pathway. Here, we report an atomic-resolution cryo-electron microscopy structure that demonstrates that the wild-type channel can also adopt this dilated state. All-atom simulations corroborate this conformation is congruent with the electrophysiological characteristics of the C-type inactivated state, namely, residual K+ conductance and altered ion specificity, and help rationalize why inactivation is accelerated or impeded by certain mutations. In summary, this study establishes the molecular basis for an important self-regulatory mechanism in eukaryotic K+ channels, laying a solid foundation for further studies.

IP-10 and MIG are sensitive markers of early virological response to HIV-1 integrase inhibitors.

Background: Interferon-inducible protein-10 (IP-10) and monokine induced by interferon-gamma (MIG) are chemokines recognized as inflammatory biomarkers during HIV-1 infection. We assessed their early and long-term dynamics after initiation of antiretroviral treatment (ART). Methods: Persons with HIV-1 (PWH) aged>18 years starting their first ART in 2015-2021 in a prospective cohort (n=73) were included. IP-10 and MIG plasma levels were quantified using a multiplexed bead-based assay. Results: IP-10 and MIG plasma levels showed a significant and consistent reduction following ART (80% integrase inhibitor [INSTI]-based) initiation, starting at day 20 and maintained throughout the study period (48 months), paralleling the HIV-1 RNA decay and CD4+ count recovery (p<0·001). At baseline, PWH≥ 50 years, CDC stage C and CD4+ count<350cells/mm3 had higher levels of IP-10 (p=0·022, p=0·001 and p=0·002, respectively) and MIG (p<0·001, p=0·024 and p=0·069, respectively). All of them matched their counterparts several months following ART initiation. MIG levels showed a greater decrease at day 10 in those treated with INSTI (p=0·038). Low-level HIV-1 viremia did not impact MIG or IP-10 levels. Conclusion: Plasma IP-10 and MIG showed an early significant decline following ART initiation, with greater early declines in MIG levels in INSTI-based regimens. These findings suggest a strong impact of HIV-1 viremia on IP-10 and MIG levels.

Inactivation of the Kv2.1 channel through electromechanical coupling.

The Kv2.1 voltage-activated potassium (Kv) channel is a prominent delayed-rectifier Kv channel in the mammalian central nervous system, where its mechanisms of activation and inactivation are critical for regulating intrinsic neuronal excitability1,2. Here we present structures of the Kv2.1 channel in a lipid environment using cryo-electron microscopy to provide a framework for exploring its functional mechanisms and how mutations causing epileptic encephalopathies3-7 alter channel activity. By studying a series of disease-causing mutations, we identified one that illuminates a hydrophobic coupling nexus near the internal end of the pore that is critical for inactivation. Both functional and structural studies reveal that inactivation in Kv2.1 results from dynamic alterations in electromechanical coupling to reposition pore-lining S6 helices and close the internal pore. Consideration of these findings along with available structures for other Kv channels, as well as voltage-activated sodium and calcium channels, suggests that related mechanisms of inactivation are conserved in voltage-activated cation channels and likely to be engaged by widely used therapeutics to achieve state-dependent regulation of channel activity.

Procalcitonin and C-reactive protein to rule out early bacterial coinfection in COVID-19 critically ill patients.

PURPOSE: Although the prevalence of community-acquired respiratory bacterial coinfection upon hospital admission in patients with coronavirus disease 2019 (COVID-19) has been reported to be < 5%, almost three-quarters of patients received antibiotics. We aim to investigate whether procalcitonin (PCT) or C-reactive protein (CRP) upon admission could be helpful biomarkers to identify bacterial coinfection among patients with COVID-19 pneumonia. METHODS: We carried out a multicentre, observational cohort study including consecutive COVID-19 patients admitted to 55 Spanish intensive care units (ICUs). The primary outcome was to explore whether PCT or CRP serum levels upon hospital admission could predict bacterial coinfection among patients with COVID-19 pneumonia. The secondary outcome was the evaluation of their association with mortality. We also conducted subgroups analyses in higher risk profile populations. RESULTS: Between 5 February 2020 and 21 December 2021, 4076 patients were included, 133 (3%) of whom presented bacterial coinfection. PCT and CRP had low area under curve (AUC) scores at the receiver operating characteristic (ROC) curve analysis [0.57 (95% confidence interval (CI) 0.51-0.61) and 0.6 (95% CI, 0.55-0.64), respectively], but high negative predictive values (NPV) [97.5% (95% CI 96.5-98.5) and 98.2% (95% CI 97.5-98.9) for PCT and CRP, respectively]. CRP alone was associated with bacterial coinfection (OR 2, 95% CI 1.25-3.19; p = 0.004). The overall 15, 30 and 90 days mortality had a higher trend in the bacterial coinfection group, but without significant difference. PCT ≥ 0.12 ng/mL was associated with higher 90 days mortality. CONCLUSION: Our study suggests that measurements of PCT and CRP, alone and at a single time point, are not useful for ruling in or out bacterial coinfection in viral pneumonia by COVID-19.

Recommendations for modernizing infant vaccination schedules with combination vaccines in Colombia and Peru.

The objective of this article was to consider the vaccination challenges in Colombia and Peru and the role of pediatric combination vaccines in overcoming these challenges. Barriers to including new vaccines with more antigens remain apparent in parts of these countries, where vaccine-preventable diseases in infants continue to be a major problem. The challenges include the heterogeneity of vaccine coverage within each country and in neighboring countries, which can contribute to poor rates of vaccination coverage; the adverse impact of the inward migration of unvaccinated individuals, which has favored the re-emergence of vaccine-preventable diseases; vaccine shortages; and the impact of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic and the associated shifts in health care resources. To improve the coverage of pediatric vaccines in Colombia and Peru, it will be necessary to ensure the widespread integration into vaccine schedules of combination vaccines containing diphtheria, tetanus, acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b and hepatitis B antigens with a three-dose primary series delivered at 2, 4 and 6 months of age followed by a booster at 18 months of age. Such vaccines play important roles in preventing diphtheria, tetanus and pertussis; eradicating polio; and providing boosting against H. influenzae type b.

El objetivo de este artículo es considerar los desafíos que se enfrentan en Colombia y Perú con respecto a la vacunación y el papel de las vacunas combinadas pediátricas para superar estos desafíos. Los obstáculos para incluir vacunas nuevas con más antígenos siguen siendo evidentes en algunos lugares de estos países, donde las enfermedades prevenibles por vacunación en menores de 1 año continúan siendo un grave problema. Entre los desafíos se incluye la heterogeneidad de la cobertura de vacunación en cada país y en los países vecinos, lo que puede contribuir con que se registren tasas bajas de cobertura de vacunación; el impacto adverso de la migración interna de personas no vacunadas, lo que ha favorecido la reaparición de enfermedades prevenibles por vacunación; la escasez de vacunas, y el impacto de la pandemia del coronavirus de tipo 2 causante del síndrome respiratorio agudo grave (SARS-CoV-2) y los consiguientes cambios en los recursos de atención médica. Para mejorar la cobertura de las vacunas pediátricas en Colombia y Perú será necesario integrar de manera generalizada en los calendarios de vacunación vacunas combinadas con antígenos de difteria, tétanos, tos ferina acelular, poliovirus inactivados, Haemophilus influenzae tipo b y hepatitis B con una serie primaria de tres dosis administradas a los 2, 4 y 6 meses de edad, seguida de un refuerzo a los 18 meses de edad. Esas vacunas desempeñan un papel esencial en la prevención de la difteria, el tétanos y la tos ferina; la erradicación de la polio; y el refuerzo contra H. influenzae tipo b.

O objetivo deste artigo foi avaliar os desafios da vacinação na Colômbia e no Peru e o papel das vacinas pediátricas combinadas na superação de tais desafios. Os obstáculos para incluir novas vacinas com mais antígenos permanecem visíveis em partes desses países, onde doenças imunopreveníveis em lactentes continuam a ser um grande problema. Os desafios incluem a heterogeneidade da cobertura vacinal dentro de cada país e nos países vizinhos, o que pode contribuir para baixas taxas de cobertura vacinal; o impacto adverso da migração interna de pessoas não vacinadas, o que favoreceu o ressurgimento de doenças imunopreveníveis; a escassez de vacinas; e o impacto da pandemia de síndrome respiratória aguda grave do coronavírus 2 (SARS-CoV-2) e mudanças relacionadas nos recursos de atenção à saúde. Para melhorar a cobertura das vacinas pediátricas na Colômbia e no Peru, será necessário assegurar sua integração generalizada em esquemas de vacinas combinadas contendo antígenos de difteria, tétano, pertussis acelular, poliovírus inativado, Haemophilus influenzae tipo B e hepatite B, com uma série primária de três doses aplicadas aos 2, 4 e 6 meses de idade seguidas de um reforço aos 18 meses de idade. Tais vacinas desempenham papéis importantes na prevenção da difteria, tétano e coqueluche; na erradicação da poliomielite; e no reforço contra H. influenzae tipo b.

Interleukin 18 (IL-18) and IL-3 in Extracellular Vesicles: Biomarkers for Durable Elite Control of HIV-1.

Plasma extracellular vesicle (EV)-associated cytokines were quantified in people with HIV (PWH) with different virological control status, including elite controllers (EC) who maintain persistent control (PC) or not (TC). Cytokine signatures and pathways were determined for each group. Median EV-associated cytokine levels were higher among PWH than HIV-uninfected. EC showed the highest levels of EV-associated cytokines among PWH with PC levels higher than TC levels. IL-18 levels best distinguished PWH from uninfected controls, and EC from ART-treated, and IL-3 distinguished PC from TC. The role of EV-cytokines in intercellular communication and endogenous control of HIV expression should be investigated further.

Recommendations for modernizing infant vaccination schedules with combination vaccines in Colombia and Peru

[ABSTRACT]. The objective of this article was to consider the vaccination challenges in Colombia and Peru and the role of pediatric combination vaccines in overcoming these challenges. Barriers to including new vaccines with more antigens remain apparent in parts of these countries, where vaccine-preventable diseases in infants continue to be a major problem. The challenges include the heterogeneity of vaccine coverage within each country and in neighboring countries, which can contribute to poor rates of vaccination coverage; the adverse impact of the inward migration of unvaccinated individuals, which has favored the re-emergence of vaccine-preventable diseases; vaccine shortages; and the impact of the severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2) pandemic and the associated shifts in health care resources. To improve the coverage of pediatric vaccines in Colombia and Peru, it will be necessary to ensure the widespread integration into vaccine sched- ules of combination vaccines containing diphtheria, tetanus, acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b and hepatitis B antigens with a three-dose primary series delivered at 2, 4 and 6 months of age followed by a booster at 18 months of age. Such vaccines play important roles in preventing diphtheria, tetanus and pertussis; eradicating polio; and providing boosting against H. influenzae type b.

[RESUMEN]. El objetivo de este artículo es considerar los desafíos que se enfrentan en Colombia y Perú con respecto a la vacunación y el papel de las vacunas combinadas pediátricas para superar estos desafíos. Los obstáculos para incluir vacunas nuevas con más antígenos siguen siendo evidentes en algunos lugares de estos países, donde las enfermedades prevenibles por vacunación en menores de 1 año continúan siendo un grave pro- blema. Entre los desafíos se incluye la heterogeneidad de la cobertura de vacunación en cada país y en los países vecinos, lo que puede contribuir con que se registren tasas bajas de cobertura de vacunación; el impacto adverso de la migración interna de personas no vacunadas, lo que ha favorecido la reaparición de enfermedades prevenibles por vacunación; la escasez de vacunas, y el impacto de la pandemia del corona- virus de tipo 2 causante del síndrome respiratorio agudo grave (SARS-CoV-2) y los consiguientes cambios en los recursos de atención médica. Para mejorar la cobertura de las vacunas pediátricas en Colombia y Perú será necesario integrar de manera generalizada en los calendarios de vacunación vacunas combinadas con antígenos de difteria, tétanos, tos ferina acelular, poliovirus inactivados, Haemophilus influenzae tipo b y hepatitis B con una serie primaria de tres dosis administradas a los 2, 4 y 6 meses de edad, seguida de un refuerzo a los 18 meses de edad. Esas vacunas desempeñan un papel esencial en la prevención de la difteria, el tétanos y la tos ferina; la erradicación de la polio; y el refuerzo contra H. influenzae tipo b.

[RESUMO]. O objetivo deste artigo foi avaliar os desafios da vacinação na Colômbia e no Peru e o papel das vacinas pediátricas combinadas na superação de tais desafios. Os obstáculos para incluir novas vacinas com mais antígenos permanecem visíveis em partes desses países, onde doenças imunopreveníveis em lactentes con- tinuam a ser um grande problema. Os desafios incluem a heterogeneidade da cobertura vacinal dentro de cada país e nos países vizinhos, o que pode contribuir para baixas taxas de cobertura vacinal; o impacto adverso da migração interna de pessoas não vacinadas, o que favoreceu o ressurgimento de doenças imu- nopreveníveis; a escassez de vacinas; e o impacto da pandemia de síndrome respiratória aguda grave do coronavírus 2 (SARS-CoV-2) e mudanças relacionadas nos recursos de atenção à saúde. Para melhorar a cobertura das vacinas pediátricas na Colômbia e no Peru, será necessário assegurar sua integração gen- eralizada em esquemas de vacinas combinadas contendo antígenos de difteria, tétano, pertussis acelular, poliovírus inativado, Haemophilus influenzae tipo B e hepatite B, com uma série primária de três doses aplica- das aos 2, 4 e 6 meses de idade seguidas de um reforço aos 18 meses de idade. Tais vacinas desempenham papéis importantes na prevenção da difteria, tétano e coqueluche; na erradicação da poliomielite; e no reforço contra H. influenzae tipo b.

Recommendations for modernizing infant vaccination schedules with combination vaccines in Colombia and Peru / Recomendaciones para modernizar los calendarios de vacunación infantil con vacunas combinadas en Colombia y Perú / Recomendações para modernizar os esquemas de vacinação infantil com vacinas combinadas na Colômbia e no Peru

ABSTRACT The objective of this article was to consider the vaccination challenges in Colombia and Peru and the role of pediatric combination vaccines in overcoming these challenges. Barriers to including new vaccines with more antigens remain apparent in parts of these countries, where vaccine-preventable diseases in infants continue to be a major problem. The challenges include the heterogeneity of vaccine coverage within each country and in neighboring countries, which can contribute to poor rates of vaccination coverage; the adverse impact of the inward migration of unvaccinated individuals, which has favored the re-emergence of vaccine-preventable diseases; vaccine shortages; and the impact of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic and the associated shifts in health care resources. To improve the coverage of pediatric vaccines in Colombia and Peru, it will be necessary to ensure the widespread integration into vaccine schedules of combination vaccines containing diphtheria, tetanus, acellular pertussis, inactivated poliovirus, Haemophilus influenzae type b and hepatitis B antigens with a three-dose primary series delivered at 2, 4 and 6 months of age followed by a booster at 18 months of age. Such vaccines play important roles in preventing diphtheria, tetanus and pertussis; eradicating polio; and providing boosting against H. influenzae type b.

RESUMEN El objetivo de este artículo es considerar los desafíos que se enfrentan en Colombia y Perú con respecto a la vacunación y el papel de las vacunas combinadas pediátricas para superar estos desafíos. Los obstáculos para incluir vacunas nuevas con más antígenos siguen siendo evidentes en algunos lugares de estos países, donde las enfermedades prevenibles por vacunación en menores de 1 año continúan siendo un grave problema. Entre los desafíos se incluye la heterogeneidad de la cobertura de vacunación en cada país y en los países vecinos, lo que puede contribuir con que se registren tasas bajas de cobertura de vacunación; el impacto adverso de la migración interna de personas no vacunadas, lo que ha favorecido la reaparición de enfermedades prevenibles por vacunación; la escasez de vacunas, y el impacto de la pandemia del coronavirus de tipo 2 causante del síndrome respiratorio agudo grave (SARS-CoV-2) y los consiguientes cambios en los recursos de atención médica. Para mejorar la cobertura de las vacunas pediátricas en Colombia y Perú será necesario integrar de manera generalizada en los calendarios de vacunación vacunas combinadas con antígenos de difteria, tétanos, tos ferina acelular, poliovirus inactivados, Haemophilus influenzae tipo b y hepatitis B con una serie primaria de tres dosis administradas a los 2, 4 y 6 meses de edad, seguida de un refuerzo a los 18 meses de edad. Esas vacunas desempeñan un papel esencial en la prevención de la difteria, el tétanos y la tos ferina; la erradicación de la polio; y el refuerzo contra H. influenzae tipo b.

RESUMO O objetivo deste artigo foi avaliar os desafios da vacinação na Colômbia e no Peru e o papel das vacinas pediátricas combinadas na superação de tais desafios. Os obstáculos para incluir novas vacinas com mais antígenos permanecem visíveis em partes desses países, onde doenças imunopreveníveis em lactentes continuam a ser um grande problema. Os desafios incluem a heterogeneidade da cobertura vacinal dentro de cada país e nos países vizinhos, o que pode contribuir para baixas taxas de cobertura vacinal; o impacto adverso da migração interna de pessoas não vacinadas, o que favoreceu o ressurgimento de doenças imunopreveníveis; a escassez de vacinas; e o impacto da pandemia de síndrome respiratória aguda grave do coronavírus 2 (SARS-CoV-2) e mudanças relacionadas nos recursos de atenção à saúde. Para melhorar a cobertura das vacinas pediátricas na Colômbia e no Peru, será necessário assegurar sua integração generalizada em esquemas de vacinas combinadas contendo antígenos de difteria, tétano, pertussis acelular, poliovírus inativado, Haemophilus influenzae tipo B e hepatite B, com uma série primária de três doses aplicadas aos 2, 4 e 6 meses de idade seguidas de um reforço aos 18 meses de idade. Tais vacinas desempenham papéis importantes na prevenção da difteria, tétano e coqueluche; na erradicação da poliomielite; e no reforço contra H. influenzae tipo b.

Tenofovir disoproxil fumarate/emtricitabine and severity of coronavirus disease 2019 in people with HIV infection.

BACKGROUND: Effective, safe, and affordable antivirals are needed for coronavirus disease 2019 (COVID-19). Several lines of research suggest that tenofovir may be effective against COVID-19, but no large-scale human studies with appropriate adjustment for comorbidities have been conducted. METHODS: We studied HIV-positive individuals on antiretroviral therapy (ART) in 2020 at 69 HIV clinics in Spain. We collected data on sociodemographics, ART, CD4+ cell count, HIV-RNA viral-load, comorbidities and the following outcomes: laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, COVID-19 hospitalization, intensive care unit (ICU) admission and death. We compared the 48-week risks for individuals receiving tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC), tenofovir alafenamide (TAF)/FTC, abacavir (ABC)/lamivudine (3TC), and other regimes. All estimates were adjusted for clinical and sociodemographic characteristics via inverse probability weighting. RESULTS: Of 51 558 eligible individuals, 39.6% were on TAF/FTC, 11.9% on TDF/FTC, 26.6% on ABC/3TC, 21.8% on other regimes. There were 2402 documented SARS-CoV-2 infections (425 hospitalizations, 45 ICU admissions, 37 deaths). Compared with TAF/FTC, the estimated risk ratios (RR) (95% confidence interval) of hospitalization were 0.66 (0.43, 0.91) for TDF/FTC and 1.29 (1.02, 1.58) for ABC/3TC, the RRs of ICU admission were 0.28 (0.11, 0.90) for TDF/FTC and 1.39 (0.70, 2.80) for ABC/3TC, and the RRs of death were 0.37 (0.23, 1.90) for TDF/FTC and 2.02 (0.88-6.12) for ABC/3TC. The corresponding RRs of hospitalization for TDF/FTC were 0.49 (0.24, 0.81) in individuals ≥50 years and 1.15 (0.59, 1.93) in younger individuals. DISCUSSION: Compared with other antiretrovirals, TDF/FTC lowers COVID-19 severity among HIV-positive individuals with virological control. This protective effect may be restricted to individuals aged 50 years and older.

Structures of the T cell potassium channel Kv1.3 with immunoglobulin modulators.

The Kv1.3 potassium channel is expressed abundantly on activated T cells and mediates the cellular immune response. This role has made the channel a target for therapeutic immunomodulation to block its activity and suppress T cell activation. Here, we report structures of human Kv1.3 alone, with a nanobody inhibitor, and with an antibody-toxin fusion blocker. Rather than block the channel directly, four copies of the nanobody bind the tetramer's voltage sensing domains and the pore domain to induce an inactive pore conformation. In contrast, the antibody-toxin fusion docks its toxin domain at the extracellular mouth of the channel to insert a critical lysine into the pore. The lysine stabilizes an active conformation of the pore yet blocks ion permeation. This study visualizes Kv1.3 pore dynamics, defines two distinct mechanisms to suppress Kv1.3 channel activity with exogenous inhibitors, and provides a framework to aid development of emerging T cell immunotherapies.

Viruses Previously Identified in Brazil as Belonging to HIV-1 CRF72_BF1 Represent Two Closely Related Circulating Recombinant Forms, One of Which, Designated CRF122_BF1, Is Also Circulating in Spain.

Circulating recombinant forms (CRFs) are important components of the HIV-1 pandemic. Those derived from recombination between subtype B and subsubtype F1, with 18 reported, most of them of South American origin, are among the most diverse. In this study, we identified a HIV-1 BF1 recombinant cluster that is expanding in Spain, transmitted mainly via heterosexual contact, which, analyzed in near full-length genomes in four viruses, exhibited a coincident BF1 mosaic structure, with 12 breakpoints, that fully coincided with that of two viruses (10BR_MG003 and 10BR_MG005) from Brazil, previously classified as CRF72_BF1. The three remaining Brazilian viruses (10BR_MG002, 10BR_MG004, and 10BR_MG008) previously identified as CRF72_BF1 exhibited mosaic structures highly similar, but not identical, to that of the Spanish viruses and to 10BR_MG003 and 10BR_MG005, with discrepant subtypes in two short genome segments, located in pol and gp120env. Based on these results, we propose that the five viruses from Brazil previously identified as CRF72_BF1 actually belong to two closely related CRFs, one comprising 10BR_MG002, 10BR_MG004, and 10BR_MG008, which keep their CRF72_BF1 designation, and the other, designated CRF122_BF1, comprising 10BR_MG003, 10BR_MG005, and the viruses of the identified Spanish cluster. Three other BF1 recombinant genomes, two from Brazil and one from Italy, previously identified as unique recombinant forms, were classified as CRF72_BF1. CRF122_BF1, but not CRF72_BF1, was associated with protease L89M substitution, which was reported to contribute to antiretroviral drug resistance. Phylodynamic analyses estimate the emergence of CRF122_BF1 in Brazil around 1987. Given their close phylogenetic relationship and similar structures, the grouping of CRF72_BF1 and CRF122_BF1 in a CRF family is proposed.

Major candidate variables to guide personalised treatment with steroids in critically ill patients with COVID-19: CIBERESUCICOVID study.

PURPOSE: Although there is evidence supporting the benefits of corticosteroids in patients affected with severe coronavirus disease 2019 (COVID-19), there is little information related to their potential benefits or harm in some subgroups of patients admitted to the intensive care unit (ICU) with COVID-19. We aim to investigate to find candidate variables to guide personalized treatment with steroids in critically ill patients with COVID-19. METHODS: Multicentre, observational cohort study including consecutive COVID-19 patients admitted to 55 Spanish ICUs. The primary outcome was 90-day mortality. Subsequent analyses in clinically relevant subgroups by age, ICU baseline illness severity, organ damage, laboratory findings and mechanical ventilation were performed. High doses of corticosteroids (≥ 12 mg/day equivalent dexamethasone dose), early administration of corticosteroid treatment (< 7 days since symptom onset) and long term of corticosteroids (≥ 10 days) were also investigated. RESULTS: Between February 2020 and October 2021, 4226 patients were included. Of these, 3592 (85%) patients had received systemic corticosteroids during hospitalisation. In the propensity-adjusted multivariable analysis, the use of corticosteroids was protective for 90-day mortality in the overall population (HR 0.77 [0.65-0.92], p = 0.003) and in-hospital mortality (SHR 0.70 [0.58-0.84], p < 0.001). Significant effect modification was found after adjustment for covariates using propensity score for age (p = 0.001 interaction term), Sequential Organ Failure Assessment (SOFA) score (p = 0.014 interaction term), and mechanical ventilation (p = 0.001 interaction term). We observed a beneficial effect of corticosteroids on 90-day mortality in various patient subgroups, including those patients aged ≥ 60 years; those with higher baseline severity; and those receiving invasive mechanical ventilation at ICU admission. Early administration was associated with a higher risk of 90-day mortality in the overall population (HR 1.32 [1.14-1.53], p < 0.001). Long-term use was associated with a lower risk of 90-day mortality in the overall population (HR 0.71 [0.61-0.82], p < 0.001). No effect was found regarding the dosage of corticosteroids. Moreover, the use of corticosteroids was associated with an increased risk of nosocomial bacterial pneumonia and hyperglycaemia. CONCLUSION: Corticosteroid in ICU-admitted patients with COVID-19 may be administered based on age, severity, baseline inflammation, and invasive mechanical ventilation. Early administration since symptom onset may prove harmful.

Methodology of a Large Multicenter Observational Study of Patients with COVID-19 in Spanish Intensive Care Units.

INTRODUCTION: The COVID-19 pandemic created tremendous challenges for health-care systems. Intensive care units (ICU) were hit with a large volume of patients requiring ICU admission, mechanical ventilation, and other organ support with very high mortality. The Centro de Investigación Biomédica en Red-Enfermedades Respiratorias (CIBERES), a network of Spanish researchers to investigate in respiratory disease, commissioned the current proposal in response to the Instituto de Salud Carlos III (ISCIII) call. METHODS: CIBERESUCICOVID is a multicenter, observational, prospective/retrospective cohort study of patients with COVID-19 admitted to Spanish ICUs. Several work packages were created, including study population and ICU data collection, follow-up, biomarkers and miRNAs, data management and quality. RESULTS: This study included 6102 consecutive patients admitted to 55 ICUs homogeneously distributed throughout Spain and the collection of blood samples from more than 1000 patients. We enrolled a large population of COVID-19 ICU-admitted patients including baseline characteristics, ICU and MV data, treatments complications, and outcomes. The in-hospital mortality was 31%, and 76% of patients required invasive mechanical ventilation. A 3-6 month and 1 year follow-up was performed. Few deaths after 1 year discharge were registered. Low anti-SARS-CoV-2 S antibody levels predict mortality in critical COVID-19. These antibodies contribute to prevent systemic dissemination of SARS-CoV-2. The severity of COVID-19 impacts the circulating miRNA profile. Plasma miRNA profiling emerges as a useful tool for risk-based patient stratification in critically ill COVID-19 patients. CONCLUSIONS: We present the methodology used in a large multicenter study sponsored by ISCIII to determine the short- and long-term outcomes in patients with COVID-19 admitted to more than 50 Spanish ICUs.

Structure of the Shaker Kv channel and mechanism of slow C-type inactivation.

Voltage-activated potassium (Kv) channels open upon membrane depolarization and proceed to spontaneously inactivate. Inactivation controls neuronal firing rates and serves as a form of short-term memory and is implicated in various human neurological disorders. Here, we use high-resolution cryo-electron microscopy and computer simulations to determine one of the molecular mechanisms underlying this physiologically crucial process. Structures of the activated Shaker Kv channel and of its W434F mutant in lipid bilayers demonstrate that C-type inactivation entails the dilation of the ion selectivity filter and the repositioning of neighboring residues known to be functionally critical. Microsecond-scale molecular dynamics trajectories confirm that these changes inhibit rapid ion permeation through the channel. This long-sought breakthrough establishes how eukaryotic K+ channels self-regulate their functional state through the plasticity of their selectivity filters.

Predictors of low-level HIV viraemia and virological failure in the era of integrase inhibitors: A Spanish nationwide cohort.

OBJECTIVES: To pinpoint factors associated with low-level viraemia (LLV) and virological failure (VF) in people living with HIV in the era of high-efficacy antiretroviral treatment (ART) and widespread use of integrase strand transfer inhibitor (INSTIs)-based ART. METHODS: We included adults aged > 18 years starting their first ART between 2015 and 2018 in the Spanish HIV/AIDS Research Network National Cohort (CoRIS). Low-level viraemia was defined as plasma viral load (pVL) of 50-199 copies/mL at weeks 48 and 72 and VF was defined as pVL ≥ 50 copies/mL at week 48 and pVL ≥ 200 copies/mL at week 72. Multivariable logistic regression models assessed the impact on LLV and VF of baseline CD4 T-cell count, CD4/CD8 T-cell ratio and pVL, initial ART classes, age at ART initiation, time between HIV diagnosis and ART initiation, gender and transmission route. RESULTS: Out of 4186 participants, 3120 (76.0%) started INSTIs, 455 (11.1%) started boosted protease inhibitors (bPIs) and 443 (10.8%) started nonnucleoside reverse transcriptase inhibitors (NNRTIs), either of them with two nucleos(t)ide reverse transcriptase inhibitors (NRTIs). Low-level viraemia was met in 2.5% of participants and VF in 4.3%. There were no significant differences throughout the years for both virological outcomes. Baseline HIV-1 RNA > 5 log10 copies/mL was the only consistent predictor of higher risk of LLV [adjusted odds ratio (aOR) = 9.8, 95% confidence interval (CI): 2.0-48.3] and VF (aOR = 5.4, 95% CI: 1.9-15.1), even in participants treated with INSTIs. CONCLUSIONS: The rates of LLV and VF were low but remained steady throughout the years. Baseline HIV-1 RNA > 5 log10 copies/mL showed a persistent association with LLV and VF even in participants receiving INSTIs.

Massive Release of CD9+ Microvesicles in Human Immunodeficiency Virus Infection, Regardless of Virologic Control.

BACKGROUND: The role of extracellular vesicles (EVs) in human immunodeficiency virus (HIV) pathogenesis is unknown. We examine the cellular origin of plasma microvesicles (MVs), a type of ectocytosis-derived EV, the presence of mitochondria in MVs, and their relationship to circulating cell-free mitochondrial deoxyribonucleic acid (ccf-mtDNA) in HIV-infected patients and controls. METHODS: Five participant groups were defined: 30 antiretroviral therapy (ART)-naive; 30 ART-treated with nondetectable viremia; 30 elite controllers; 30 viremic controllers; and 30 HIV-uninfected controls. Microvesicles were quantified and characterized from plasma samples by flow cytometry. MitoTrackerDeepRed identified MVs containing mitochondria and ccf-mtDNA was quantified by real-time polymerase chain reaction. RESULTS: Microvesicle numbers were expanded at least 10-fold in all HIV-infected groups compared with controls. More than 79% were platelet-derived MVs. Proportions of MVs containing mitochondria (22.3% vs 41.6%) and MV mitochondrial density (706 vs 1346) were significantly lower among HIV-infected subjects than controls, lowest levels for those on ART. Microvesicle numbers correlated with ccf-mtDNA levels that were higher among HIV-infected patients. CONCLUSIONS: A massive release of platelet-derived MVs occurs during HIV infection. Some MVs contain mitochondria, but their proportion and mitochondrial densities were lower in HIV infection than in controls. Platelet-derived MVs may be biomarkers of platelet activation, possibly reflecting pathogenesis even in absence of HIV replication.

Toxoplasma gondii-Induced Neutrophil Extracellular Traps Amplify the Innate and Adaptive Response.

Toxoplasmosis affects one-third of the human population worldwide. Humans are accidental hosts and are infected after consumption of undercooked meat and water contaminated with Toxoplasma gondii cysts and oocysts, respectively. Neutrophils have been shown to participate in the control of T. gondii infection in mice through a variety of effector mechanisms, such as reactive oxygen species (ROS) and neutrophil extracellular trap (NET) formation. However, few studies have demonstrated the role of neutrophils in individuals naturally infected with T. gondii. In the current study, we evaluated the activation status of neutrophils in individuals with acute or chronic toxoplasmosis and determined the role of T. gondii-induced NET formation in the amplification of the innate and adaptive immune responses. We observed that neutrophils are highly activated during acute infection through increased expression of CD66b. Moreover, neutrophils from healthy donors (HDs) cocultured with tachyzoites produced ROS and formed NETs, with the latter being dependent on glycolysis, succinate dehydrogenase, gasdermin D, and neutrophil elastase. Furthermore, we observed elevated levels of the chemokines (CXC motif) CXCL8 and (CC motif) CCL4 ligands in plasma from patients with acute toxoplasmosis and production by neutrophils from HDs exposed to T. gondii. Finally, we showed that T. gondii-induced NETs activate neutrophils and promote the recruitment of autologous CD4+ T cells and the production of interferon gamma (IFN-γ), tumor necrosis factor (TNF), interleukin 6 (IL-6), IL-17, and IL-10 by peripheral blood mononuclear cells. In conclusion, we demonstrated that T. gondii activates neutrophils and promotes the release of NETs, which amplify human innate and adaptive immune responses. IMPORTANCE Approximately one-third of the human population is estimated to be chronically infected with the obligate intracellular parasite Toxoplasma gondii. Humans are accidental hosts that are infected with T. gondii after consumption of undercooked meat or contaminated water. Neutrophils have been shown to control T. gondii growth by different mechanisms, including neutrophil extracellular traps (NETs). In the current study, we observed that neutrophils are highly activated during acute toxoplasmosis. We also determined that T. gondii-induced NETs are dependent on the energetic profile of neutrophils as well as the production of ROS and gasdermin D (GSDMD) cleavage. In addition, we showed that T. gondii-induced NETs activate neutrophils, promote the recruitment of autologous CD4+ T cells, and induce the production of cytokines by peripheral blood mononuclear cells, amplifying the innate and adaptive immune responses.

Clinical and Multimodal Imaging Findings and Risk Factors for Ocular Involvement in a Presumed Waterborne Toxoplasmosis Outbreak, Brazil1.

In 2015, an outbreak of presumed waterborne toxoplasmosis occurred in Gouveia, Brazil. We conducted a 3-year prospective study on a cohort of 52 patients from this outbreak, collected clinical and multimodal imaging findings, and determined risk factors for ocular involvement. At baseline examination, 12 (23%) patients had retinochoroiditis; 4 patients had bilateral and 2 had macular lesions. Multimodal imaging revealed 2 distinct retinochoroiditis patterns: necrotizing focal retinochoroiditis and punctate retinochoroiditis. Older age, worse visual acuity, self-reported recent reduction of visual acuity, and presence of floaters were associated with retinochoroiditis. Among patients, persons >40 years of age had 5 times the risk for ocular involvement. Five patients had recurrences during follow-up, a rate of 22% per person-year. Recurrences were associated with binocular involvement. Two patients had late ocular involvement that occurred >34 months after initial diagnosis. Patients with acquired toxoplasmosis should have long-term ophthalmic follow-up, regardless of initial ocular involvement.