Involvement of SIRT1 and SIRT3 in Effects of Hypoxic Hypobaric Preconditioning on Hippocampal Damage Induced by Chronic Cerebral Hypoperfusion in C57/6j and a7nAchRs(-/-) Mice / Participación de SIRT1 y SIRT3 en los Efectos del Precondicionamiento Hipobárico Hipóxico sobre el Daño del Hipocampo Inducido por Hipoperfusión Cerebral Crónica en Ratones C57/6j y a7nAchRs (-/-)

SUMMARY: Hypoxic preconditioning is known to induce neuroprotection, but its effects and pathways in chronic brain pathology still unknown. The aim was to establish an involvement of a7 subunit of nicotinic acetylcholine receptors (a7nAchRs), and sirtuins of 1 (SIRT1) and 3 (SIRT3) types in the effects of hypoxic hypobaric preconditioning on brain damage in mice with chronic cerebral hypoperfusion caused by the left common carotid artery occlusion. The male C57/6j (C57, wild type) and a7nAchRs(-/-) mice were divided to six experimental groups (10 mice per group): sham-operated C57, C57 with chronic cerebral hypoperfusion, C57 with hypoxic hypobaric preconditioning and chronic cerebral hypoperfusion, sham-operated a7nAchRs(-/-) mice, a7nAchRs(-/-) with chronic cerebral hypoperfusion, a7nAchRs(-/-) with hypoxic hypobaric preconditioning and chronic cerebral hypoperfusion. For preconditioning, mice were exposed to hypoxia by "lifting" in barochamber to simulated altitude of 5600 m a.s.l. for 1 h/day on 3 consecutive days before surgical manipulation. Expressions of SIRT1, SIRT3 in brain tissue, and histopathological changes of the hippocampi were examined. It was shown that 8-week chronic hypoperfusion of the brain, caused by unilateral occlusion of the common carotid artery, was accompanied by injury to the neurons of the hippocampi of both hemispheres, which was more pronounced on the side of the occlusion. This damage, as well as the mechanisms of neuroprotection induced by hypoxic preconditioning, were maintained for at least 8 weeks by mechanisms mediated through a7nAChRs. Deficite of a7nAChRs was accompanied with reduction of neuronal damage caused CCH in 8 weeks, as well as preconditioning effects, and lead to compensatory activation of regulatory and protective mechanisms mediated by SIRT1, in normal conditions and in CCH. In wild-type (C57) mice, protective mechanisms in CCH were realized to a greater extent by increased expression of SIRT3 in both hemispheres of the brain.

Se sabe que el precondicionamiento hipóxico induce neuroprotección, pero aún se desconocen sus efectos y vías en la patología cerebral crónica. El objetivo fue establecer la participación de la subunidad a7 de los receptores nicotínicos de acetilcolina (a7nAchR) y las sirtuinas de tipo 1 (SIRT1) y 3 (SIRT3) en los efectos del precondicionamiento hipóxico hipobárico sobre el daño cerebral en ratones con hipoperfusión cerebral crónica causada por la oclusión de la arteria carótida común izquierda. Los ratones macho C57/6j (C57, tipo salvaje) y a7nAchRs(-/-) se dividieron en seis grupos experimentales (10 ratones por grupo): C57 con operación simulada, C57 con hipoperfusión cerebral crónica, C57 con precondicionamiento hipobárico hipóxico y crónica. hipoperfusión cerebral, ratones a7nAchRs(-/-) operados de forma simulada, a7nAchRs(-/-) con hipoperfusión cerebral crónica, a7nAchRs(-/-) con precondicionamiento hipobárico hipóxico e hipoperfusión cerebral crónica. Para el preacondicionamiento, los ratones fueron expuestos a hipoxia "levantándolos" en una cámara de barro a una altitud simulada de 5600 m s.n.m. durante 1 h/día durante 3 días consecutivos antes de la manipulación quirúrgica. Se examinaron las expresiones de SIRT1, SIRT3 en tejido cerebral y los cambios histopatológicos de los hipocampos. Se demostró que la hipoperfusión cerebral crónica de 8 semanas, causada por la oclusión unilateral de la arteria carótida común, se acompañaba de lesión de las neuronas del hipocampo de ambos hemisferios y que era más pronunciada en el lado de la oclusión. Este daño, así como los mecanismos de neuroprotección inducidos por el precondicionamiento hipóxico, se mantuvieron durante al menos 8 semanas mediante mecanismos mediados por a7nAChR. El déficit de a7nAChR se acompañó de una reducción del daño neuronal causado por CCH en 8 semanas, así como de efectos de precondicionamiento, y condujo a una activación compensatoria de mecanismos reguladores y protectores mediados por SIRT1, en condiciones normales y en CCH. En ratones de tipo salvaje (C57), los mecanismos de protección en CCH se realizaron en mayor medida mediante una mayor expresión de SIRT3 en ambos hemisfe- rios del cerebro.

Estrategias de destete y desmonte de cánula nasal de alto flujo en adultos / Adult High-Flow Nasal Cannula Weaning and Disassembly Strategies

Introducción: La cánula nasal de alto flujo es un sistema que utiliza una mezcla de aire-oxígeno humidificado y calentado con un caudal de hasta 70 litros por minuto. Es utilizada mayoritariamente en la insuficiencia respiratoria aguda de origen hipoxémico, donde ha demostrado brindar mayor comodidad y poder resolutivo de la hipoxemia, en comparación con la oxigenoterapia convencional. Aunque se conocen sus indicaciones y estrategia de seguimiento, en la práctica clínica no es claro su proceso de destete/desmonte. Objetivo: Identificar en la bibliografía la literatura existente acerca de estrategias de destete/desmonte de la cánula nasal de alto flujo en adultos. Métodos: Se realizó una revisión bibliográfica en las bases de datos del portal regional de la BVS, PubMed, Web Of Science, Scopus y Google scholar, sin límite de tiempo y es- tructurando una ecuación PIO con palabras clave y operadores booleanos. Se asumieron artículos publicados en inglés y español, texto completo. Resultados: En la bibliografía, aún se reporta discrepancia en el proceso de destete y desmonte de la cánula nasal de alto flujo, pero en la mayoría de los estudios encontrados en esta revisión se propone disminuir la FiO2 primero de forma gradual (5-10%) hasta valores de 30-50% y, posteriormente, el flujo. Para desmontarla, se podría considerar tener una FiO2 entre 30-50%, flujo entre 20-30 litros por minuto, SaO2 >92%, con adecuada mecánica respiratoria y estado de conciencia. Conclusión: Aún no existe unanimidad en el proceso de destete/desmonte en la cánula nasal de alto flujo en el paciente adulto.

Introduction: The high-flow nasal cannula is a system that uses a humidified and heated air-oxygen mixture with a flow rate of up to 70 liters per minute. It is mostly used in acute respiratory failure of hypoxemic origin, where it has been shown to provide greater comfort and resolving power of hypoxemia, compared to conventional oxygen therapy. Although its indications and follow-up strategy are known, in clinical practice the weaning/weaning process is not clear. Objective: To identify in the bibliography the existing literature on weaning/ weaning strategies of high-flow nasal cannula in adults. Methods: A bibliographic review was carried out in the databases of the regional portal of the BVS, PubMed, Web Of Science, Scopus and Google scholar, without time limit and structuring a PIO equation with keywords and boléan connectors. Articles published in English and Spanish, full text, were assumed. Results: The literature still reports discrepancy in the process of weaning and disassembling the high-flow nasal cannula, but most of the studies found in this review propose to decrease the FiO2 first gradually (5-10%) to values of 30-50% and then the flow. To dismantle it, one could consider having a FiO2 between 30-50%, flow between 20-30 liters per minute, SaO2 >92%, with adequate respiratory mechanics and state of consciousness. Conclusion: There is still no unanimity on the weaning/weaning process in the high- flow nasal cannula in the adult patient.

Impairment of Autophagic Flux After Hypobaric Hypoxia Potentiates Oxidative Stress and Cognitive Function Disturbances in Mice / 神经科学通报·英文版

Acute hypobaric hypoxic brain damage is a potentially fatal high-altitude sickness. Autophagy plays a critical role in ischemic brain injury, but its role in hypobaric hypoxia (HH) remains unknown. Here we used an HH chamber to demonstrate that acute HH exposure impairs autophagic activity in both the early and late stages of the mouse brain, and is partially responsible for HH-induced oxidative stress, neuronal loss, and brain damage. The autophagic agonist rapamycin only promotes the initiation of autophagy. By proteome analysis, a screen showed that protein dynamin2 (DNM2) potentially regulates autophagic flux. Overexpression of DNM2 significantly increased the formation of autolysosomes, thus maintaining autophagic flux in combination with rapamycin. Furthermore, the enhancement of autophagic activity attenuated oxidative stress and neurological deficits after HH exposure. These results contribute to evidence supporting the conclusion that DNM2-mediated autophagic flux represents a new therapeutic target in HH-induced brain damage.

Human ESC-derived vascular cells promote vascular regeneration in a HIF-1α dependent manner

Hypoxia-inducible factor (HIF-1α), a core transcription factor responding to changes in cellular oxygen levels, is closely associated with a wide range of physiological and pathological conditions. However, its differential impacts on vascular cell types and molecular programs modulating human vascular homeostasis and regeneration remain largely elusive. Here, we applied CRISPR/Cas9-mediated gene editing of human embryonic stem cells and directed differentiation to generate HIF-1α-deficient human vascular cells including vascular endothelial cells, vascular smooth muscle cells, and mesenchymal stem cells (MSCs), as a platform for discovering cell type-specific hypoxia-induced response mechanisms. Through comparative molecular profiling across cell types under normoxic and hypoxic conditions, we provide insight into the indispensable role of HIF-1α in the promotion of ischemic vascular regeneration. We found human MSCs to be the vascular cell type most susceptible to HIF-1α deficiency, and that transcriptional inactivation of ANKZF1, an effector of HIF-1α, impaired pro-angiogenic processes. Altogether, our findings deepen the understanding of HIF-1α in human angiogenesis and support further explorations of novel therapeutic strategies of vascular regeneration against ischemic damage.

Budd-Chiari syndrome with hepatopulmonary syndrome: a case report and literature review / 中华儿科杂志

Objective: To summarize the clinical features and prognosis of Budd-Chiari syndrome with hepatopulmonary syndrome (HPS) in children. Methods: The clinical data of a child who had Budd-Chiari syndrome with HPS treated at the Department of Pediatrics of the First Affiliated Hospital of Zhengzhou University in December 2016 was analyzed retrospectively. Taking "Budd-Chiari syndrome" and "hepatopulmonary syndrome" in Chinese or English as the keywords, literature was searched at CNKI, Wanfang, China Biomedical Literature Database and PubMed up to July 2023. Combined with this case, the clinical characteristics, diagnosis, treatment and prognosis of Budd-Chiari syndrome with HPS in children under the age of 18 were summarized. Results: A 13-year-old boy, presented with cyanosis and chest tightness after activities for 6 months, and yellow staining of the skin for 1 week. Physical examination at admission not only found mild yellow staining of the skin and sclera, but also found cyanosis of the lips, periocular skin, and extremities. Laboratory examination showed abnormal liver function with total bilirubin 53 μmol/L, direct bilirubin 14 μmol/L, and indirect bilirubin 39 μmol/L, and abnormal blood gas analysis with the partial pressure of oxygen of 54 mmHg (1 mmHg=0.133 kPa), the partial pressure of carbon dioxide of 31 mmHg, and the alveolar-arterial oxygen gradient of 57 mmHg. Hepatic vein-type Budd-Chiari syndrome, cirrhosis, and portal hypertension were indicated by abdominal CT venography. Contrast-enhanced transthoracic echocardiography (CE-TTE) was positive. After symptomatic and supportive treatment, this patient was discharged and received oxygen therapy outside the hospital. At follow-up until March 2023, there was no significant improvement in hypoxemia, accompanied by limited daily activities. Based on the literature, there were 3 reports in English while none in Chinese, 3 cases were reported. Among a total of 4 children, the chief complaints were dyspnea, cyanosis, or hypoxemia in 3 cases, and unknown in 1 case. There were 2 cases diagnosed with Budd-Chiari syndrome with HPS at the same time due to respiratory symptoms, and 2 cases developed HPS 1.5 years and 8.0 years after the diagnosis of Budd-Chiari syndrome respectively. CE-TTE was positive in 2 cases and pulmonary perfusion imaging was positive in 2 cases. Liver transplantation was performed in 2 cases and their respiratory function recovered well; 1 case received oxygen therapy, with no improvement in hypoxemia; 1 case was waiting for liver transplantation. Conclusions: The onset of Budd-Chiari syndrome with HPS is insidious. The most common clinical manifestations are dyspnea and cyanosis. It can reduce misdiagnosis to confirm intrapulmonary vascular dilatations with CE-TTE at an early stage. Liver transplantation is helpful in improving the prognosis.

Safety of modified T-piece resuscitator versus nasal cannula oxygen in electronic bronchoscopy for infants: a prospective randomized controlled study / 中国当代儿科杂志

OBJECTIVES@#To optimize the oxygen therapy regimens for infants with pulmonary diseases during bronchoscopy.@*METHODS@#A prospective randomized, controlled, and single-center clinical trial was conducted on 42 infants who underwent electronic bronchoscopy from July 2019 to July 2021. These infants were divided into a nasal cannula (NC) group and a modified T-piece resuscitator (TPR) group using a random number table. The lowest intraoperative blood oxygen saturation was recorded as the primary outcome, and intraoperative heart rate and respiratory results were recorded as the secondary outcomes.@*RESULTS@#Compared with the NC group, the modified TPR group had a significantly higher level of minimum oxygen saturation during surgery and a significantly lower incidence rate of hypoxemia (P<0.05). In the modified TPR group, there were 6 infants with mild hypoxemia, 2 with moderate hypoxemia, and 1 with severe hypoxemia, while in the NC group, there were 3 infants with mild hypoxemia, 5 with moderate hypoxemia, and 9 with severe hypoxemia (P<0.05). The modified TPR group had a significantly lower incidence rate of intraoperative respiratory rhythm abnormalities than the NC group (P<0.05), but there was no significant difference in the incidence rate of arrhythmias between the two groups (P>0.05).@*CONCLUSIONS@#Modified TPR can significantly reduce the risk of hypoxemia in infants with pulmonary diseases during electronic bronchoscopy, and TPR significantly decreases the severity of hypoxemia and the incidence of respiratory rhythm abnormalities compared with traditional NC.

Cobalt Chloride as a Hypoxia Mimicking Agent Induced HIF-1α and mTOR Expressions of Human Umbilical Cord Mesenchymal Stem Cells

ABSTRACT Objective: To assess the effects of cobalt chloride (CoCl2) as a hypoxia mimicking agent on human umbilical cord mesenchymal stem cells (hUCMSCs) expression of HIF-1α and mTOR for use in regenerative dentistry. Material and Methods: Human umbilical cord mesenchymal stem cells were isolated and then cultured. The characteristics of stemness were screened and confirmed by flow cytometry. The experiment was conducted on hypoxia (H) and normoxia (N) groups. Each group was divided and incubated into 24-, 48-, and 72-hours observations. Hypoxic treatment was performed using 100 µM CoCl2 on 5th passage cells in a conventional incubator (37°C; 5CO2). Then, immunofluorescence of HIF-1α and mTOR was done. Data was analyzed statistically using One-way ANOVA and Tukey's HSD. Results: Significant differences were found between normoxic and hypoxic groups on HIF-1α (p=0.015) and mTOR (p=0.000) expressions. The highest HIF-1α expression was found at 48 hours in the hypoxia group, while for mTOR at 24 hours in the hypoxia group. Conclusion: Hypoxia using cobalt chloride was able to increase human umbilical cord mesenchymal stem cells expression of HIF-1α and mTOR.

Parto vaginal operatório / Operative vaginal delivery

PONTOS-CHAVE Quando utilizados na técnica correta, fórcipes e vácuo-extratores apresentam baixos índices de complicações. Para o feto com sinais de hipóxia no período expulsivo, o parto vaginal operatório tem potencial para reduzir a exposição aos fatores intraparto que promovem a encefalopatia hipóxico-isquêmica. Fórcipes médios e/ou rotacionais são opções apropriadas em circunstâncias selecionadas e exigem habilidade e experiência. Os fórcipes são mais resolutivos do que os vácuo-extratores para o parto vaginal operatório, porém são mais associados a lacerações perineais graves. Céfalo-hematoma é mais provável de ocorrer com o aumento na duração da vácuo-extração. Os vácuo-extratores de campânulas flexíveis apresentam taxas maiores de falha, porém apresentam menores incidências de trauma no couro cabeludo do neonato. (AU)

Efectos cerebrales del oxígeno y el dióxido de carbono en el síndrome de dificultad respiratoria aguda / Cerebral Effects of Oxygen and Carbon Dioxide in Acute Respiratory Distress Syndrome

Introducción: El síndrome de dificultad respiratoria aguda producido por la COVID-19 provoca alteraciones en el intercambio de oxígeno y la excreción de dióxido de carbono con consecuencias neurológicas. Objetivo: Describir las implicaciones del oxígeno y el dióxido de carbono sobre la dinámica cerebral durante el tratamiento ventilatorio del síndrome de dificultad respiratoria aguda en el accidente cerebrovascular. Métodos: Se realizó una búsqueda en bases referenciales como: PubMed/Medline, SciELO, Google Académico y BVS Cuba. Los términos incluidos fueron brain-lung crosstalk, ARDS, mechanical ventilation, COVID-19 related stroke, ARDS related stroke y su traducción al español. Fueron referenciados libros de neurointensivismo y ventilación mecánica artificial. El período de búsqueda incluyó los últimos 20 años. Se seleccionaron 46 bibliografías que cumplieron con los criterios de selección. Resultados: Se ha descrito que los niveles de oxígeno y dióxido de carbono participan en la neurorregulación vascular en pacientes con daño cerebral. Algunas alteraciones alusivas son la vasodilatación cerebral refleja o efectos vasoconstrictores con reducción de la presión de perfusión cerebral. Como consecuencia aumenta la presión intracraneal y aparecen afectaciones neurocognitivas, isquemia cerebral tardía o herniación del tronco encefálico. Conclusiones: El control de la oxigenación y la excreción de dióxido de carbono resultaron cruciales para mantener la homeostasis neuronal, evita la disminución de la presión de perfusión cerebral y el aumento de la presión intracraneal. Se sugiere evitar la hipoxemia e hiperoxemia, limitar o eludir la hipercapnia y usar hiperventilación hipocápnica solo en condiciones de herniación del tallo encefálico(AU)

Introduction: The acute respiratory distress syndrome produced by COVID-19 causes alterations in the exchange of oxygen and the excretion of carbon dioxide with neurological consequences. Objective: To describe the implications of oxygen and carbon dioxide on brain dynamics during ventilatory treatment of acute respiratory distress syndrome in stroke. Methods: A search was carried out in referential bases such as PubMed/Medline, SciELO, Google Scholar and VHL Cuba. The terms included were brain-lung crosstalk, ARDS, mechanical ventilation, COVID-19 related stroke, ARDS related stroke and their translation into Spanish. Books on neurointensive care and artificial mechanical ventilation were referenced. The search period included the last 20 years. Forty six bibliographies that met the selection criteria were selected. Results: Oxygen and carbon dioxide levels have been described to participate in vascular neuroregulation in patients with brain damage. Some allusive alterations are reflex cerebral vasodilatation or vasoconstrictor effects with reduced cerebral perfusion pressure. As a consequence, intracranial pressure increases and neurocognitive impairments, delayed cerebral ischemia or brainstem herniation appear. Conclusions: The control of oxygenation and the excretion of carbon dioxide were crucial to maintain neuronal homeostasis, avoiding the decrease in cerebral perfusion pressure and the increase in intracranial pressure. It is suggested to avoid hypoxemia and hyperoxemia, limit or avoid hypercapnia, and use hypocapnic hyperventilation only in conditions of brainstem herniation(AU)

Manejo de la hipoxia durante ventilación unipulmonar en un paciente con absceso mediastinal y mediastinitis para toracotomía abierta. Reporte de caso / Hypoxia Management during One-Lung Ventilation in a Patient with Mediastinal Abscess and Mediastinitis for Open Thoracotomy. Case Report

Introducción: la mayoría de los pacientes que se someten a cirugía torácica pueden ser clasificados en el grupo de alto riesgo para hipoxia, especialmente cuando se decide por una ventilación unipulmonar, debido al desequilibrio V/Q; por lo tanto, se han desa-rrollado nuevas estrategias ventilatorias y maniobras de rescate para hipoxia. Curso clínico: presentamos una paciente de 85 años de edad sin comorbilidades programada para toracotomía abierta y manejada con ventilación unipulmonar. Durante el mane-jo anestésico, se presenta hipoxia secundaria a desequilibrio V/Q y choque hipovolémi-co hemorrágico, con respuesta positiva a las maniobras de rescate para hipoxia. Con-clusión: es importante prevenir en la medida de lo posible la hipoxia en la ventilación unipulmonar, siguiendo las nuevas estrategias ventilatorias. Sin embargo, cuando se presenta una crisis, no debemos retrasar las maniobras de rescate de forma moderna. (AU)

Introduction: most of the patients undergoing thoracic surgery fit in the high risk group for hypoxia, especially when deciding to use one-lung ventilation due to the V/Q mis-match; therefore, new ventilation strategies and hypoxia rescue manoeuvres have been developed. Clinical course: we present an 85-year old female with no major co-morbidities scheduled for open thoracotomy and managed with one-lung ventilation. During the course of the anaesthetic management, hypoxia presents secondary to V/Q mismatch and haemorrhagic hypovolemic shock, with a positive response to hypoxia rescue manoeuvres. Conclusion: it is important to prevent as much as we can the hy-poxia in a one-lung ventilation following the new ventilation strategies. Although when facing a crisis, proper hypoxia management with a modern approach should not be de-layed. (AU)

Importance of assessing biomarkers and physiological parameters of anemia-induced tissue hypoxia in the perioperative period

Abstract Anemia is associated with increased risk of Acute Kidney Injury (AKI), stroke and mortality in perioperative patients. We sought to understand the mechanism(s) by assessing the integrative physiological responses to anemia (kidney, brain), the degrees of anemia-induced tissue hypoxia, and associated biomarkers and physiological parameters. Experimental measurements demonstrate a linear relationship between blood Oxygen Content (CaO2) and renal microvascular PO2 (y = 0.30x + 6.9, r2= 0.75), demonstrating that renal hypoxia is proportional to the degree of anemia. This defines the kidney as a potential oxygen sensor during anemia. Further evidence of renal oxygen sensing is demonstrated by proportional increase in serum Erythropoietin (EPO) during anemia (y = 93.806*10−0.02, r2= 0.82). This data implicates systemic EPO levels as a biomarker of anemia-induced renal tissue hypoxia. By contrast, cerebral Oxygen Delivery (DO2) is defended by a profound proportional increase in Cerebral Blood Flow (CBF), minimizing tissue hypoxia in the brain, until more severe levels of anemia occur. We hypothesize that the kidney experiences profound early anemia-induced tissue hypoxia which contributes to adaptive mechanisms to preserve cerebral perfusion. At severe levels of anemia, renal hypoxia intensifies, and cerebral hypoxia occurs, possibly contributing to the mechanism(s) of AKI and stroke when adaptive mechanisms to preserve organ perfusion are overwhelmed. Clinical methods to detect renal tissue hypoxia (an early warning signal) and cerebral hypoxia (a later consequence of severe anemia) may inform clinical practice and support the assessment of clinical biomarkers (i.e., EPO) and physiological parameters (i.e., urinary PO2) of anemia-induced tissue hypoxia. This information may direct targeted treatment strategies to prevent adverse outcomes associated with anemia.

Impacto del decúbito prono en pacientes con COVID-19 grave en un hospital de agudos de la Ciudad Autónoma de Buenos Aires / Impact of the prone positioning in patients with severe COVID-19 in an acute care hospital in the Autonomous City of Buenos Aires

Introducción: El decúbito prono fue la estrategia más utilizada en pacientes con CO VID-19 e hipoxemia refractaria. Nuestro objetivo fue describir las características clínicas y evolución de los pacientes con COVID-19 grave que requirieron este procedimiento. Evaluar la relación entre factores de riesgo y mortalidad. Material y métodos: Estudio descriptivo retrospectivo observacional. Se incluyeron los pacientes mayores de 18 años con COVID-19 bajo asistencia respiratoria mecánica que requirieron decúbito prono. Se efectuó seguimiento durante 28 días. Se registraron las complicaciones asociadas al decúbito prono. Se analizaron factores asociados a la mortalidad utilizando regresión de Cox. Resultados: Se realizó decúbito prono en 28 pacientes. La edad promedio fue de 52,43 años y una mediana de índice de Charlson de 1 [0,00, 2,00]. La mediana de días de asistencia respiratoria mecánica fue de 17,00 [RIQ 13,00, 23,00] y un 28,6% logró ser extubado. La mediana de días en UTI fue de 19,50 [RIQ 14.00, 23.50] con una mortalidad del 53,6%. El 35,7% necesitó dos ciclos de decúbito prono con una duración predominante de 24-36 h. El 89,4% tuvo lesiones de úlceras por presión. Los que fallecieron tuvieron menos días de UTI (16 vs. 28; p = 0,006) y solo uno de ellos había logrado ser extubado (1 vs. 7, p = 0,011). No se encontraron factores asociados a la mortalidad en la regresión de Cox. Conclusión: La población estudiada resultó predominantemente masculina y de edad promedio cercana a la quinta década de vida, con una mortalidad aproximada al 50%. No se encontró relación estadísticamente significativa entre factores de riesgo y mortalidad.

Introduction: Prone positioning (PP) was the most used strategy in patients with CO VID-19 and refractory hypoxemia. Our objective was to describe the clinical character istics and evolution of patients with severe Covid-19 who required this procedure. Also to evaluate the relationship between risk factors and mortality. Materials and method: Observational retrospective descriptive study. Patients older than 18 years old with COVID-19 under mechanical ventilation (AVM) who required PP were included. Follow-up was carried out for 28 days. Complications associated with PP were recorded. Factors associated with mortality were analyzed using Cox regression. Results: Prone position was performed in 28 patients. The average age was 52.43 years and a median Charlson Score of 1 [0.00, 2.00]. The median number of days of AVM was 17.00 [IQR 13.00, 23.00] and 28.6% managed to be extubated. The median number of days in the ICU was 19.50 [IQR 14.00, 23.50] with a mortality of 53.6%. 35.7% needed 2 PD cycles with a predominant duration of 24-36 hours. 89.4% had pressure ulcers. Those who died spent fewer days in ICU (16 vs 28; p=0.006) and only one of them had managed to be extubated (1 vs 7, p = 0.011). No factors associated with mortality were found in the Cox regression. Conclusion: The study population consisted predominantly of males in an average age close to the fifth decade, with an approximate mortality of 50%. No statistically significant relationship was found between risk factors and mortality.

Hipoxemia y el riesgo de hipertensión arterial en apnea obstructiva del sueño / Hypoxemia and the Hypertension Risk in Obstructive Sleep Apnea

Hay poca información sobre el rol de la hipoxemia como factor de riesgo de hipertensión arterial (HTA) en pacientes con apnea obstructiva del sueño. El objetivo de este estudio fue evaluar la hipoxemia como factor de riesgo independiente de HTA en un modelo de trabajo basado en pacientes reales examinados en una unidad de sueño. Métodos: estudio retrospectivo. Modelo predictivo mediante regresión logística múltiple para establecer la relación entre HTA y edad, sexo, índice de masa corporal (IMC), índice de apneas e hipopneas por hora de registro (IAH) y tiempo de saturación de oxígeno debajo de 90% (T90 > 3%). Resultados: incluimos 3854 pacientes (edad mediana 55 años), predominio varones (61.5%). Según el modelo, las variables asociadas con HTA fueron: edad (OR 3.27 ­ 3.29, IC95% 2.83 ­ 3.80, p < 0.0001), sexo masculino (OR 1.35, IC95% 1.17 ­ 1.56, p < 0.001), obesidad (OR 1.83, IC95% 1.59 ­ 2.11, p < 0.0001), IAH ≥ 15 eventos por hora (OR 1.22, IC95% 1.05 ­ 1.43, p < 0.01) y T90 ≥ 3% (OR 1.56 ­ 1.57, IC95% 1.32 ­ 1.84, p < 0.0001). Conclusiones: en una población clínica con sospecha de apnea obstructiva del sueño, la hipoxemia (T90 ≥ 3%) se asoció con hipertensión arterial. (AU);

There is limited information about the role of hypoxemia degree as a risk factor for hypertension (HTN) in patients with obstructive sleep apnea (OSA). The objective of this study is to assess hypoxemia as an independent risk factor for HTN in a work model based on real-life patients examined at sleep unit. Methods: this retrospective study consisted of a predictive model using multiple logistic regression to establish the relationship between HTN and age, sex, body mass index (BMI), apnea/hypopnea index (AHI) and time below SO2 ≤ 90% (T90 ≥ 3%). Results: we included 3.854 patients (median age: 55 years), mostly men (61.5%). According to the model, the variables that were significantly associated with HTN were: age (OR: 3.27 ­ 3.29, CI95% 2.83 ­ 3.80, p < 0.0001), male sex (OR 1.35, CI95% 1.17 ­ 1.56, p < 0.001), Obesity (OR 1.83, CI95% 1.59 ­ 2.11, p < 0.0001), AHI > 15 events per hour (OR 1.22, CI95% 1.05 ­ 1.43, p < 0.01) and T90 ≥ 3% (OR 1.56 ­ 1.57, CI95% 1.32 ­ 1.84, p < 0.0001). Conclusion: in a clinical population of subjects suspected of OSA, nocturnal hypoxemia measure as T90 ≥ 3% was associated with HTN. (AU);

Concentraciones de oxígeno intermitentes tienen impacto en el desarrollo postnatal temprano de ratas Sprague-Dawley: efectos en CA1 del hipocampo / Intermittent oxygen concentrations have an impact on the early postnatal development of Sprague-Dawley rats: effects on hippocampal CA1

El periodo postnatal temprano se caracteriza por rápido crecimiento cerebral, posiblemente relacionado con variaciones del oxígeno tisular. Esto ha motivado el estudio de protocolos que suministran diferentes concentraciones de oxígeno intermitentes, para observar sus efectos morfológicos y cerebrales. Se utilizaron 52 crías de ratas Sprague Dawley, distribuidas en igual número a cuatro grupos experimentales, Control (C, 21 %O2), Hipoxia Intermitente (HI, 11 %O2), Hiperoxia Intermitente (HOI, 30 %O2) e Hipoxia Hiperoxia Intermitente (HHI, 11 % -30 %O2). Los protocolos consideraron 5 ciclos de 5 minutos de dosificación, durante 50 minutos diarios. Se realizó en una cámara semihermética entre los días 5 al 11 postnatales. Las evaluaciones de crecimiento corporal y cuantificación neuronal, se realizaron en las crías macho, en el día 28 postnatal. El peso corporal en el grupo hipoxia intermitente mostró diferencias significativas respecto al grupo hiperoxia intermitente (HI vs HOI, p<0,01) y al grupo hipoxia-hiperoxia Intermitente (HI vs HHI, p< 0,001). La talla corporal disminuyó en el grupo hipoxia-hiperoxia intermitente con diferencias significativas respecto del grupo control (C vs HHI, p<0,05) y respecto del grupo hipoxia intermitente (HHI vs HI, p< 0,01). El conteo neuronal en el área CA1 del hipocampo aumentó en el grupo hipoxia intermitente con diferencias significativas respecto a los grupos control (C vs HI; p<0,05), al grupo hiperoxia intermitente (HI vs HOI; p<0,001) y al grupo hipoxia-hiperoxia intermitente (HI vs HHI; p<0,001). Finalmente, el grupo hipoxia- hiperoxia Intermitente disminuyó significativamente en la cantidad de neuronas en comparación al grupo hiperoxia intermitente (HHI vs HOI; p<0,001). La hipoxia intermitente mostró resultados beneficiosos en el crecimiento corporal y cantidad de neuronas en el área CA1 del hipocampo, en contraste, la hipoxia hiperoxia intermitente experimentó resultados adversos con disminución de estas variables, en el periodo postnatal temprano de la rata.

SUMMARY: The early postnatal period is characterized by rapid brain growth, possibly related to variations in tissue oxygen. This has motivated the study of protocols that supply different intermittent oxygen concentrations, to observe their morphological and cerebral effects. Fifty-two pups Sprague-Dawley rats were distributed in equal numbers into four experimental groups, Control (C, 21 %O), Intermittent Hypoxia (HI, 11 %O), Intermittent Hyperoxia (HOI, 30 %O2) and Intermittent Hypoxia Hyperoxia (HHI, 11 % - 30 %O2). The protocols considered 5 cycles of 5 min of dosing, for 50 min diary. It was performed in a semi- hermetic chamber between 5 to 11postnatal days. The evaluations of body growth and neuronal quantification were analyzed in male pups, on postnatal day 28. Body weight in the intermittent hypoxia group showed significant differences compared to the intermittent hyperoxia group (HI vs HOI, p<0.01) and the intermittent hypoxia- hyperoxia group (HI vs HHI, p<0.001). Body size decreased in the Intermittent hypoxia-hyperoxia group with significant differences compared to the control group (C vs HHI, p<0.05) and with respect to the intermittent hypoxia group (HHI vs HI, p<0.01). The neuronal count in the area CA1 of the hippocampus increased in the intermittent hypoxia group with significant differences compared to the control groups (C vs HI; p<0.05), to the intermittent hyperoxia group (HI vs HOI; p< 0.001) and the intermittent hypoxia-hyperoxia group (HI vs HHI; p<0.001). Finally, the intermittent hypoxia- hyperoxia group decreased significantly in the number of neurons compared with the intermittent hyperoxia group (HHI vs HOI; p<0.001). Intermittent hypoxia showed beneficial results in body growth and the number of neurons in the CA1 area of the hippocampus, in contrast, intermittent hypoxia-hyperoxia experienced adverse results with a decrease in these variables, in the early postnatal period of the rat.

Research Progress on Molecular Changes in Pulmonary Hypoxia and Cause of Death Identification in Mechanical Asphyxia / 法医学杂志

Lung is the largest organ of the respiratory system. During hypoxia, pulmonary cells undergo rapid damage changes and activate the self-rescue pathways, thus leading to complex biomacromolecule modification. Death from mechanical asphyxia refers to death due to acute respiratory disorder caused by mechanical violence. Because of the absence of characteristic signs in corpse, the accurate identification of mechanical asphyxia has always been the difficulty in forensic pathology. This paper reviews the biomacromolecule changes under the pulmonary hypoxia condition and discusses the possibility of application of these changes to accurate identification of death from mechanical asphyxia, aiming to provide new ideas for related research.

Read-through circular RNA rt-circ-HS promotes hypoxia inducible factor 1α expression and renal carcinoma cell proliferation, migration and invasiveness / 北京大学学报(医学版)

OBJECTIVE@#To identify and characterize read-through RNAs and read-through circular RNAs (rt-circ-HS) derived from transcriptional read-through hypoxia inducible factor 1α (HIF1α) and small nuclear RNA activating complex polypeptide 1 (SNAPC1) the two adjacent genes located on chromosome 14q23, in renal carcinoma cells and renal carcinoma tissues, and to study the effects of rt-circ-HS on biological behavior of renal carcinoma cells and on regulation of HIF1α.@*METHODS@#Reverse transcription-polymerase chain reaction (RT-PCR) and Sanger sequencing were used to examine expression of read-through RNAs HIF1α-SNAPC1 and rt-circ-HS in different tumor cells. Tissue microarrays of 437 different types of renal cell carcinoma (RCC) were constructed, and chromogenic in situ hybridization (ISH) was used to investigate expression of rt-circ-HS in different RCC types. Small interference RNA (siRNA) and artificial overexpression plasmids were designed to examine the effects of rt-circ-HS on 786-O and A498 renal carcinoma cell proliferation, migration and invasiveness by cell counting kit 8 (CCK8), EdU incorporation and Transwell cell migration and invasion assays. RT-PCR and Western blot were used to exa-mine expression of HIF1α and SNAPC1 RNA and proteins after interference of rt-circ-HS with siRNA, respectively. The binding of rt-circ-HS with microRNA 539 (miR-539), and miR-539 with HIF1α 3' untranslated region (3' UTR), and the effects of these interactions were investigated by dual luciferase reporter gene assays.@*RESULTS@#We discovered a novel 1 144 nt rt-circ-HS, which was derived from read-through RNA HIF1α-SNAPC1 and consisted of HIF1α exon 2-6 and SNAPC1 exon 2-4. Expression of rt-circ-HS was significantly upregulated in 786-O renal carcinoma cells. ISH showed that the overall positive expression rate of rt-circ-HS in RCC tissue samples was 67.5% (295/437), and the expression was different in different types of RCCs. Mechanistically, rt-circ-HS promoted renal carcinoma cell proliferation, migration and invasiveness by functioning as a competitive endogenous inhibitor of miR-539, which we found to be a potent post-transcriptional suppressor of HIF1α, thus promoting expression of HIF1α.@*CONCLUSION@#The novel rt-circ-HS is highly expressed in different types of RCCs and acts as a competitive endogenous inhibitor of miR-539 to promote expression of its parental gene HIF1α and thus the proliferation, migration and invasion of renal cancer cells.

Activation of HIF-1α/ACLY signaling axis promotes progression of clear cell renal cell carcinoma with VHL inactivation mutation / 中华病理学杂志

Objective: To explore the potential pathogenesis of clear cell renal cell carcinoma (ccRCC) based on the HIF-1α/ACLY signaling pathway, as well as to provide new ideas for the treatment of ccRCC. Methods: Seventy-eight ccRCC cases diagnosed at the First Affiliated Hospital of Soochow University, Suzhou, China were collected. The VHL mutation was examined using exon sequencing. The expression of HIF-1α/ACLY in VHL-mutated ccRCC was evaluated using immunohistochemical staining and further validated in VHL-mutated ccRCC cell lines (786-O, A498, UM-RC-2, SNU-333, and Caki-2) using Western blot. The mRNA and protein levels of ACLY were detected using real-time quantitative PCR and Western blot after overexpression or interference with HIF-1α in ccRCC cell lines. HeLa cells were treated with CoCl2 and hypoxia (1%O2) to activate HIF-1α and then subject to the detection of the ACLY mRNA and protein levels. The potential molecular mechanism of HIF-1α-induced ACLY activation was explored through JASPAR database combined with chromatin immunoprecipitation assay (ChIP) and luciferase reporter gene assay. The effect of HIF-1α/ACLY regulation axis on lipid accumulation was detected using BODIPY staining and other cell biological techniques. The expression of ACLY was compared between patients with ccRCC and those with benign lesions, and the feasibility of ACLY as a prognostic indicator for ccRCC was explored through survival analysis. Results: Exon sequencing revealed that 55 (70.5%) of the 78 ccRCC patients harbored a VHL inactivation mutation, and HIF-1α expression was associated with ACLY protein levels. The protein levels of ACLY and HIF-1α in ccRCC cell lines carrying VHL mutation were also correlated to various degrees. Overexpression of HIF-1α in A498 cells increased the mRNA and protein levels of ACLY, and knockdown of HIF-1α in Caki-2 cells inhibited the mRNA and protein levels of ACLY (P<0.001 for all). CoCl2 and hypoxia treatment significantly increased the mRNA and protein levels of ACLY by activating HIF-1α (P<0.001 for all). The quantification of transcriptional activity of luciferase reporter gene and ChIP-qPCR results suggested that HIF-1α could directly bind to ACLY promoter region to transcriptionally activate ACLY expression and increase ACLY protein level (P<0.001 for all). The results of BODIPY staining suggested that the content of free fatty acids in cell lines was associated with the levels of HIF-1α and ACLY. The depletion of HIF-1α could effectively reduce the accumulation of lipid in cells, while the overexpression of ACLY could reverse this process. At the same time, cell function experiments showed that the proliferation rate of ccRCC cells with HIF-1α knockdown was significantly decreased, and overexpression of ACLY could restore proliferation of these tumor cells (P<0.001). Survival analysis further showed that compared with the ccRCC patients with low ACLY expression, the ccRCC patients with high ACLY expression had a poorer prognosis and a shorter median survival (P<0.001). Conclusions: VHL mutation-mediated HIF-1α overexpression in ccRCC promotes lipid synthesis and tumor progression by activating ACLY. Targeting the HIF-1α/ACLY signaling axis may provide a theoretical basis for the clinical diagnosis and treatment of ccRCC.

Salidroside improves intestinal mucosal immune status of rats under compound stress of hypoxia and training via inhibiting TLR4/NF-κB signaling pathway / 细胞与分子免疫学杂志

Objective To investigate the effect of salidroside on intestinal mucosal immune status in rats under compound stress of hypoxia and training (HTCS) and the mechanism. Methods SD rats were randomly divided into HTCS model group (model), placebo group (placebo) and salidroside group (salidro). Model group received no intervention, and placebo and salidro group received intraperitoneal injection of normal saline and salidroside, respectively. Then, ileum tissue of rats were collected and the intestinal damage was assayed by HE staining and Chiu scores. Intestinal permeability indices, including serum D-diamine oxidase (DAO), D-lactic acid (DLA) and endotoxin (END) and secretory immunoglobulin A (sIgA) of intestinal tissue were detected by ELISA. T lymphocyte subsets of intestinal tissue were detected by flow cytometry. Expression of tight junction molecules, including ZO-1, Claudin-3, occluding, were detected by PCR and western blot. Activation of TLR4/NF-κB signaling pathway was detected by Western blot analysis. Results Compared with model group and placebo group, salidro group had the decreased intestinal mucosal injury and low Chiu score, and the level of intestinal permeability indices including serum DAO, DLA and END fell off. CD4+ T cell percentage, CD4+/CD8+ ratio and sIgA level were went up, while CD8+ T cell percentage was went down. mRNA and the level of protein expressions of ZO-1, claudin-3 and occludin increased, while activation of TLR4/NF-κB signaling pathway was inhibited. Conclusion Salidroside can alleviate the intestinal barrier injury and improve intestinal mucosal immune status of rats under compound stress of hypoxia and training via inhibiting TLR4/NF-κB signalling pathway.

Responses of blood parameters and hemoglobin subtypes in plateau zokors and plateau pikas to different altitude habitats / 生理学报

The plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzoniae) are native species unique to the Qinghai-Tibetan Plateau with successful adaptation to the hypoxic environment. In this study, the number of red blood cells, hemoglobin concentration, mean hematocrit and mean volume of red blood cells were measured in plateau zokors and plateau pikas at different altitudes. Hemoglobin subtypes of two plateau animals were identified by mass spectrometry sequencing. The forward selection sites in two animals' hemoglobin subunits were analyzed by PAML4.8 program. Homologous modeling was used to analyze the effect of forward selection sites on the affinity of hemoglobin to oxygen. The adapting strategies of plateau zokors and plateau pikas to hypoxia at different altitudes were analyzed through comparing blood parameters between the two species. The results indicated that, with increasing altitudes, plateau zokors responded to hypoxia by increasing red blood cell count and decreasing red blood cell volume, while plateau pikas took the opposite strategies to plateau zokors. In erythrocytes of plateau pikas, both adult α2β2 and fetal α2ε2 hemoglobins were identified, while erythrocytes of plateau zokors only had adult α2β2 hemoglobin, however the affinities and the allosteric effects of the hemoglobin of plateau zokors were significantly higher than those of plateau pikas. Mechanistically, in the α and β subunits of hemoglobin of plateau zokors and pikas, the numbers and the sites of the positively selected amino acids as well as the side chain groups polarities and orientations of the amino acids differed significantly, which may result in the difference of the affinities to oxygen of hemoglobin between plateau zokors and pikas. In conclusion, the adaptive mechanisms to respond to hypoxia in blood properties of plateau zokors and plateau pikas are species-specific.

Factors affecting pulmonary arterial pressure in response to high-altitude hypoxic stress / 生理学报

The alteration of pulmonary artery pressure is an important physiological indicator to reflect the organism's adaptation to acclimatization or the pathological injury in response to high-altitude hypoxic environment. The effects of hypoxic stress at different altitudes for different time on pulmonary artery pressure are different. There are many factors involved in the changes of pulmonary artery pressure, such as the contraction of pulmonary arterial smooth muscle, hemodynamic changes, abnormal regulation of vascular activity and abnormal changes of cardiopulmonary function. Understanding of the regulatory factors of pulmonary artery pressure in hypoxic environment is crucial in clarifying the relevant mechanisms of hypoxic adaptation, acclimatization, prevention, diagnosis, treatment and prognosis of acute and chronic high-altitude diseases. In recent years, great progress has been made in the study regarding the factors affecting pulmonary artery pressure in response to high-altitude hypoxic stress. In this review, we discuss the regulatory factors and intervention measures of pulmonary arterial hypertension induced by hypoxia from the aspects of hemodynamics of circulatory system, vasoactive state and changes of cardiopulmonary function.