Clinical and epidemiological characteristics of mothers with COVID-19 and their neonates: vertical transmission. / Características clínicas y epidemiológicas de madres con COVID-19 y sus neonatos: transmisión vertical.

INTRODUCTION: COVID-19 disease can affect women at any stage of pregnancy, and newborns could become infected with SARS-CoV-2 through vertical or horizontal transmission. OBJECTIVE: To determine clinical and epidemiological characteristics of mothers with COVID-19, associated neonatal outcomes, and to evaluate SARS-CoV-2 vertical transmission. METHODS: We conducted an observational, descriptive, cross-sectional study. We included all mothers with positive serology for SARS-CoV-2 and their newborns at the Hospital Regional Docente de Trujillo from April 18 to September 30, 2020. Variables were collected from the medical records, and descriptive statistics were used for the analysis. RESULTS: A total of 647 mothers and 656 neonates were enrolled. Of all live births, 85.3% and 14.7% were term and preterm neonates, respectively. We found 1.7% (11/656) of newborns with positive RT-PCR for SARS-CoV-2; and that 27.3% (3/11) of these neonates required hospitalization. Neonatal mortality was 4/656 (0.6%), and no case was attributed to COVID-19. Of all mothers affected with COVID-19, 95.7% were asymptomatic, and 4.3% presented clinical symptoms attributed to COVID-19, most of which were mild. The most frequent obstetric complications were preeclampsia-eclampsia, prelabour rupture of membranes, and acute fetal distress. All the mothers were discharged. CONCLUSION: We found 1.7% of newborns with positive RT-PCR test for SARS-CoV-2; and that 20.1% of these neonates were hospitalized. The most frequent morbidity was neonatal sepsis and prematurity. The infection was mild among newborns, showing a 0.6% overall mortality, with no cases attributed to COVID-19. We found that only 5% of mothers presented symptoms, most of which were mild to moderate symptoms. There was no record of maternal mortality in this study group. It is not possible to conclude whether vertical transmission or intrapartum-acquired infection is responsible for neonatal COVID-19 infections.

INTRODUCCIÓN: La enfermedad de COVID-19 puede afectar a gestantes en cualquier trimestre del embarazo. Por su parte, los neonatos podrían infectarse con SARS-CoV-2 por transmisión vertical u horizontal. OBJETIVO: Determinar las características clínicas y epidemiológicas de madres con COVID-19, de sus neonatos y la transmisión vertical del SARS-CoV-2. MÉTODOS: Estudio observacional, descriptivo, transversal. Se incluyeron todas las madres con serología positiva para SARS-CoV-2 y sus neonatos nacidos en el Hospital Regional Docente de Trujillo desde el 18 de abril hasta el 30 de septiembre de 2020. La información para las variables se recogió de las historias clínicas. Para el análisis se usó estadística descriptiva. RESULTADOS: Participaron 647 madres y 656 neonatos. El 85,3% de los neonatos nació de término y el 14,7% fue prematuro. El 1,7% (11/656) tuvieron PCR-RT positivos para SARS-CoV-2, y de ellos el 27,3% (3/11) requirió hospitalizados. La mortalidad fue de 4/656 (0,6%), no atribuida a COVID-19. De las madres afectadas con COVID-19, 95,7% fue asintomática, el 4,3% presentó sintomatología clínica atribuida a COVID-19, siendo en su mayoría casos leves. Las complicaciones obstétricas más frecuentes fueron preeclampsia, eclampsia, rotura prematura de las membranas y sufrimiento fetal agudo. Todas las madres fueron dadas de alta. CONCLUSIÓN: De los neonatos estudiados, el 1,7% presentó prueba PCR-RT para SARS-CoV-2 positiva. El 20,1% fue hospitalizado. La morbilidad más frecuente fue sepsis neonatal y prematuridad. La mortalidad fue de 0,6%, ningún caso atribuido a COVID-19. El cuadro clínico de esta patología fue leve en los neonatos. El 95% de las madres con COVID-19 fueron asintomáticas. De las gestantes que presentaron cuadro clínico, tuvieron sintomatología leve a moderada. No se tuvo registro de mortalidad materna en el grupo de estudio. No se puede concluir si se trata de casos de transmisión vertical del SARS-CoV-2 o estamos frente a casos de posible infección neonatal adquirida intraparto.

Elimination of fast inactivation in Kv4 A-type potassium channels by an auxiliary subunit domain.

The Kv4 A-type potassium currents contribute to controlling the frequency of slow repetitive firing and back-propagation of action potentials in neurons and shape the action potential in heart. Kv4 currents exhibit rapid activation and inactivation and are specifically modulated by K-channel interacting proteins (KChIPs). Here we report the discovery and functional characterization of a modular K-channel inactivation suppressor (KIS) domain located in the first 34 aa of an additional KChIP (KChIP4a). Coexpression of KChIP4a with Kv4 alpha-subunits abolishes fast inactivation of the Kv4 currents in various cell types, including cerebellar granule neurons. Kinetic analysis shows that the KIS domain delays Kv4.3 opening, but once the channel is open, it disrupts rapid inactivation and slows Kv4.3 closing. Accordingly, KChIP4a increases the open probability of single Kv4.3 channels. The net effects of KChIP4a and KChIP1-3 on Kv4 gating are quite different. When both KChIP4a and KChIP1 are present, the Kv4.3 current shows mixed inactivation profiles dependent on KChIP4a/KChIP1 ratios. The KIS domain effectively converts the A-type Kv4 current to a slowly inactivating delayed rectifier-type potassium current. This conversion is opposite to that mediated by the Kv1-specific "ball" domain of the Kv beta 1 subunit. Together, these results demonstrate that specific auxiliary subunits with distinct functions actively modulate gating of potassium channels that govern membrane excitability.