Surfactant Protein D Influences Mortality During Abdominal Sepsis by Facilitating Escherichia coli Colonization in the Gut.

Determine the role of surfactant protein D (SPD) in sepsis. DESIGN: Murine in vivo study. SETTING: Research laboratory at an academic medical center. PATIENTS: SPD knockout (SPD-/-) and wild-type (SPD+/+) mice. INTERVENTIONS: SPD-/- and SPD+/+ mice were subjected to cecal ligation and puncture (CLP). After CLP, Escherichia coli bacteremia was assessed in both groups. Cecal contents from both groups were cultured to assess for colonization by E. coli. To control for parental effects on the microbiome, SPD-/- and SPD+/+ mice were bred from heterozygous parents, and levels of E. coli in their ceca were measured. Gut segments were harvested from mice, and SPD protein expression was measured by Western blot. SPD-/- mice were gavaged with green fluorescent protein, expressing E. coli and recombinant SPD (rSPD). MEASUREMENTS AND MAIN RESULTS: SPD-/- mice had decreased mortality and decreased E. coli bacteremia compared with SPD+/+ mice following CLP. At baseline, SPD-/- mice had decreased E. coli in their cecal flora. When SPD-/- and SPD+/+ mice were bred from heterozygous parents and then separated after weaning, less E. coli was cultured from the ceca of SPD-/- mice. E. coli gut colonization was increased by gavage of rSPD in SPD-/- mice. The source of enteric SPD in SPD+/+ mice was the gallbladder. CONCLUSIONS: Enteral SPD exacerbates mortality after CLP by facilitating colonization of the mouse gut with E. coli.

Diabetes Mellitus Type 1 has a Higher Impact on Corneal Endothelial Cell Density and Pachymetry than Diabetes Mellitus Type 2, Independent of Age: A Meta-Regression Model.

PURPOSE: Patients with diabetes mellitus (DM) often have keratopathy. However, the compromise of the corneal endothelium in type 1 DM (T1DM) and type 2 DM (T2DM) has so far not been well characterized. METHODS: We performed a systematic literature search to find articles on humans combining T1DM and/or T2DM and the corneal endothelium. The period was from inception to June 2020. The meta-regression evaluated the role of each type of DM on corneal endothelial cell density (CED) and pachymetry. The statistical models included age as a modulator to discriminate between the normal changes due to age and the effect of the disease and to determine the impact of the disease duration. RESULTS: The initial search identified 752 records, of which 17 were included in the meta-regression. Patients with T1DM had, on average, 193 cells/mm 2 lesser than control patients ( P < 0.00001). Patients with T2DM had 151 cells/mm 2 less compared with control patients ( P < 0.00001). The loss of corneal endothelial cells was expected because the aging was similar in patients with T1DM and T2DM and their control groups. Patients with T1DM and T2DM showed an increase in pachymetry versus control patients, and in both groups, it was associated with the duration of the disease. CONCLUSIONS: Both types of DM reduced CED and increased pachymetry. These differences were higher in patients with T1DM versus control patients than patients with T2DM versus control patients. In T1DM, CED reduction was not correlated with the time from diagnosis. In both groups, patients had CED reduction due to aging similar to that of their matched control patients.

mTORC1 is a mechanosensor that regulates surfactant function and lung compliance during ventilator-induced lung injury.

The acute respiratory distress syndrome (ARDS) is a highly lethal condition that impairs lung function and causes respiratory failure. Mechanical ventilation (MV) maintains gas exchange in patients with ARDS but exposes lung cells to physical forces that exacerbate injury. Our data demonstrate that mTOR complex 1 (mTORC1) is a mechanosensor in lung epithelial cells and that activation of this pathway during MV impairs lung function. We found that mTORC1 is activated in lung epithelial cells following volutrauma and atelectrauma in mice and humanized in vitro models of the lung microenvironment. mTORC1 is also activated in lung tissue of mechanically ventilated patients with ARDS. Deletion of Tsc2, a negative regulator of mTORC1, in epithelial cells impairs lung compliance during MV. Conversely, treatment with rapamycin at the time MV is initiated improves lung compliance without altering lung inflammation or barrier permeability. mTORC1 inhibition mitigates physiologic lung injury by preventing surfactant dysfunction during MV. Our data demonstrate that, in contrast to canonical mTORC1 activation under favorable growth conditions, activation of mTORC1 during MV exacerbates lung injury and inhibition of this pathway may be a novel therapeutic target to mitigate ventilator-induced lung injury during ARDS.

In silico and in vitro analysis of cation-activated potassium channels in human corneal endothelial cells.

The corneal endothelium is the inner cell monolayer involved in the maintenance of corneal transparence by the generation of homeostatic dehydration. The glycosaminoglycans of the corneal stroma develop a continuous swelling pressure that should be counteracted by the corneal endothelial cells through active transport mechanisms to move the water to the anterior chamber. Protein transporters for sodium (Na+), potassium (K+), chloride (Cl-) and bicarbonate (HCO3-) are involved in this endothelial "pump function", however despite its physiological importance, the efflux mechanism is not completely understood. There is experimental evidence describing transendothelial diffusion of water in the absence of osmotic gradients. Therefore, it is important to get a deeper understanding of alternative models that drive the fluid transport across the endothelium such as the electrochemical gradients. Three transcriptomic datasets of the corneal endothelium were used in this study to analyze the expression of genes that encode proteins that participate in the transport and the reestablishment of the membrane potential across the semipermeable endothelium. Subsequently, the expression of the identified channels was validated in vitro both at mRNA and protein levels. The results of this study provide the first evidence of the expression of KCNN2, KCNN3 and KCNT2 genes in the corneal endothelium. Differences among the level of expression of KCNN2, KCNT2 and KCNN4 genes were found in a differentially expressed gene analysis of the dataset. Taken together these results underscore the potential importance of the ionic channels in the pathophysiology of corneal diseases. Moreover, we elucidate novel mechanisms that might be involved in the pivotal dehydrating function of the endothelium and in others physiologic functions of these cells using in silico pathways analysis.

Co-Expression Network Analysis Identifies Possible Hub Genes in Aging of the Human Prefrontal Cortex / Análisis de redes de coexpresión identifica posibles genes clave en el envejecimiento de la corteza prefrontal humana / Análise de redes de co-expressão identifica possíveis genes chave no envelhecimento do córtex pré-frontal humano

Abstract Introduction : Aging is the main risk factor for the development of chronic diseases such as cancer, diabetes, Parkinson's disease, and Alzheimer's disease. The central nervous system is particularly susceptible to progressive functional deterioration associated with age, among the brain regions the prefrontal cortex (PFC) has one of the highest involvements. Transcriptomics studies of this brain region have identified the decrease in synaptic function and activation of neuroglia cells as fundamental characteristics of the aging process. The aim of this study was to identify hub genes in the transcriptomic deregulation in the PFC aging to advance in the knowledge of this process. Materials and methods : A gene co-expression analysis was carried out for 45 people 60 to 80 years old compared with 38 people 20 to 40 years old. The networks were visualized and analyzed using Cytoscape; citoHubba was used to determine which genes had the best topological characteristics in the co-expression networks. Results : Five genes with high topological characteristics were identified. Four of them -HPCA, CACNG3, CA10, PLPPR4- were repressed and one was over-expressed -CRYAB-. Conclusion: The four repressed genes are expressed preferentially in neurons and regulate the synaptic function and the neuronal plasticity, while the overexpressed gene is typical of glial cells and is expressed as a response to neuronal damage, facilitating myelination and neuronal regeneration.

Resumen Introducción : el envejecimiento es el principal factor de riesgo para el desarrollo de enfermedades crónicas como el cáncer, la diabetes, el Parkinson y el Alzheimer. El sistema nervioso central es particularmente susceptible al deterioro funcional progresivo asociado con la edad, entre las regiones cerebrales con mayor compromiso se encuentra la corteza prefrontal (CPF). Estudios de transcriptómica de esta región han identificado como características fundamentales del proceso de envejecimiento la disminución de la función sináptica y la activación de las células de la neuroglia. No es claro cuáles son las causas iniciales, ni los mecanismos moleculares subyacentes a estas alteraciones. El objetivo de este estudio fue identificar genes clave en la desregulación transcriptómica en el envejecimiento de la CPF para avanzar en el conocimiento de este proceso. Materiales y métodos : se hizo un análisis de coexpresión de genes de los transcriptomas de 45 personas entre 60 y 80 años con el de 38 personas entre 20 y 40 años. Las redes fueron visualizadas y analizadas usando Cytoscape, se usó citoHubba para determinar qué genes tenían las mejores características topológicas en las redes de coexpresión. Resultados : se identificaron cinco genes con características topológicas altas. Cuatro de ellos -HPCA, CACNG3, CA10, PLPPR4- reprimidos y uno sobreexpresado -CRYAB-. Conclusión : los cuatro genes reprimidos se expresan preferencialmente en neuronas y regulan la función sináptica y la plasticidad neuronal, mientras el gen sobreexpresado es típico de células de la glía y se expresa como respuesta a daño neuronal facilitando la mielinización y la regeneración neuronal.

Resumo Introdução : o envelhecimento é o principal fator de risco pra o desenvolvimento de doenças crónicas como o câncer, a diabetes, o Parkinson e o Alzheimer. O sistema nervoso central é particularmente susceptível ao deterioro funcional progressivo associado à idade, uma das regiões do cérebro com maior compromisso é o pré-frontal (CPF). Estudos de transcritoma desta região têm identificado como características fundamentais do processo de envelhecimento a diminuição da função sináptica e ativação das células da neuroglia. Não é claro quais são as causas iniciais, nem os mecanismos moleculares subjacentes a estas alterações. O objetivo deste estudo foi identificar genes chave na desregulação transcritoma no envelhecimento da CPF para avançar no conhecimento deste processo. Materiais e métodos : se fez uma análise de co-expressão de genes dos transcritomas de 45 pessoas entre 60 e 80 anos com o de 38 pessoas entre 20 e 40 anos. As redes foram visualizadas e analisadas usando Cytoscape, usou-se citoHubba para determinar que genes tinham as melhores características topológicas nas redes de co-expressão. Resultados : identificaram-se cinco genes com características topológicas altas. Quatro deles -HPCA, CACNG3, CA10, PLPPR4- reprimidos e um superexpresso -CRYAB-. Conclusão : os quatro genes reprimidos se expressam preferencialmente em neurônios e regulam a função sináptica e plasticidade neuronal, enquanto o gene superexpresso é típico de células da glia e se expressa como resposta ao dano neuronal facilitado a mielinização e a regeneração neuronal.

Integrative Analysis of Global Gene Expression Identifies Opposite Patterns of Reactive Astrogliosis in Aged Human Prefrontal Cortex.

The prefrontal cortex (PFC) is one of the brain regions with more prominent changes in human aging. The molecular processes related to the cognitive decline and mood changes during aging are not completely understood. To improve our knowledge, we integrated transcriptomic data of four studies of human PFC from elderly people (58⁻80 years old) compared with younger people (20⁻40 years old) using a meta-analytic approximation combined with molecular signature analysis. We identified 1817 differentially expressed genes, 561 up-regulated and 1256 down-regulated. Pathway analysis revealed down-regulation of synaptic genes with conservation of gene expression of other neuronal regions. Additionally, we identified up-regulation of markers of astrogliosis with transcriptomic signature compatible with A1 neurotoxic astrocytes and A2 neuroprotective astrocytes. Response to interferon is related to A1 astrocytes and the A2 phenotype is mediated in aging by activation of sonic hedgehog (SHH) pathway and up-regulation of metallothioneins I and genes of the family ERM (ezrin, radixin, and moesin). The main conclusions of our study are the confirmation of a global dysfunction of the synapses in the aged PFC and the evidence of opposite phenotypes of astrogliosis in the aging brain, which we report for the first time in the present article.

Proton Pump Inhibitors and Dementia: Physiopathological Mechanisms and Clinical Consequences.

Alzheimer's disease (AD) is the most common type of dementia, mainly encompassing cognitive decline in subjects aged ≥65 years. Further, AD is characterized by selective synaptic and neuronal degeneration, vascular dysfunction, and two histopathological features: extracellular amyloid plaques composed of amyloid beta peptide (Aß) and neurofibrillary tangles formed by hyperphosphorylated tau protein. Dementia and AD are chronic neurodegenerative conditions with a complex physiopathology involving both genetic and environmental factors. Recent clinical studies have shown that proton pump inhibitors (PPIs) are associated with risk of dementia, including AD. However, a recent case-control study reported decreased risk of dementia. PPIs are a widely indicated class of drugs for gastric acid-related disorders, although most older adult users are not treated for the correct indication. Although neurological side effects secondary to PPIs are rare, several preclinical reports indicate that PPIs might increase Aß levels, interact with tau protein, and affect the neuronal microenvironment through several mechanisms. Considering the controversy between PPI use and dementia risk, as well as both cognitive and neuroprotective effects, the aim of this review is to examine the relationship between PPI use and brain effects from a neurobiological and clinical perspective.

Zinc deficiency primes the lung for ventilator-induced injury.

Mechanical ventilation is necessary to support patients with acute lung injury, but also exacerbates injury through mechanical stress-activated signaling pathways. We show that stretch applied to cultured human cells, and to mouse lungs in vivo, induces robust expression of metallothionein, a potent antioxidant and cytoprotective molecule critical for cellular zinc homeostasis. Furthermore, genetic deficiency of murine metallothionein genes exacerbated lung injury caused by high tidal volume mechanical ventilation, identifying an adaptive role for these genes in limiting lung injury. Stretch induction of metallothionein required zinc and the zinc-binding transcription factor MTF1. We further show that mouse dietary zinc deficiency potentiates ventilator-induced lung injury, and that plasma zinc levels are significantly reduced in human patients who go on to develop acute respiratory distress syndrome (ARDS) compared with healthy and non-ARDS intensive care unit (ICU) controls, as well as with other ICU patients without ARDS. Taken together, our findings identify a potentially novel adaptive response of the lung to stretch and a critical role for zinc in defining the lung's tolerance for mechanical ventilation. These results demonstrate that failure of stretch-adaptive responses play an important role in exacerbating mechanical ventilator-induced lung injury, and identify zinc and metallothionein as targets for lung-protective interventions in patients requiring mechanical ventilation.

Bioética e investigación: análisis de caso de la epidemia por el virus ébola en 2014

La epidemia por el virus Ébola, en África occidental (2014), ha suscitado una serie de interrogantes éticos en torno a las medidas de salud pública para su contención, el uso de medicamentos experimentales y el desarrollo de vacunas contra esta enfermedad. El presente trabajo explora algunas de estas preguntas desde la perspectiva de la ética en investigación biomédica. La epidemia por el virus Ébola es un modelo de estudio adecuado para abordar esfuerzos multilaterales en investigación, así como para analizar aspectos antropológicos en salud pública y determinantes sociales, económicos y políticos en salud a nivel global.

The Ebola virus epidemic in West Africa (2014) has raised some ethical questions surrounding public health measures for its containment, the use of experimental drugs and the development of vaccines against this disease. This paper explores some of these issues from the perspective of ethics in biomedical research. Ebola virus epidemic is a suitable study model to address multilateral efforts in research as well as to analyze anthropological aspects of public health and social, economic and political determinants of global health.

A epidemia pelo vírus Ebola, na África Ocidental (2014), tem levantado uma série de questões éticas em torno às medidas de saúde pública para a sua contenção, o uso de medicamentos experimentais e o desenvolvimento de vacinas contra esta doença. Este artigo explora algumas destas questões a partir da perspectiva da ética na pesquisa biomédica. A epidemia pelo vírus Ebola é um modelo de estudo adequado para abordar esforços multilaterais em pesquisa, como também para analisar aspectos antropológicos em saúde pública e determinantes sociais, econômicos e políticos em saúde a nível global.

Broad spectrum immunomodulation using biomimetic blood cell margination for sepsis therapy.

Sepsis represents a systemic inflammatory response caused by microbial infection in blood. Herein, we present a novel comprehensive approach to mitigate inflammatory responses through broad spectrum removal of pathogens, leukocytes and cytokines based on biomimetic cell margination. Using a murine model of polymicrobial sepsis induced by cecal ligation and puncture (CLP), we performed extracorporeal blood filtration with the developed microfluidic blood margination (µBM) device. Circulating bacteremia, leukocytes and cytokines in blood decreased post-filtration and significant attenuation of immune cell and cytokine responses were observed 3-5 days after intervention, indicating successful long-term immunomodulation. A dose-dependent effect on long-term immune cell count was also achieved by varying filtration time. As proof of concept for human therapy, the µBM device was scaled up to achieve ∼100-fold higher throughput (∼150 mL h(-1)). With further multiplexing, the µBM technique could be applied in clinical settings as an adjunctive treatment for sepsis and other inflammatory diseases.

Isoflurane Ameliorates Acute Lung Injury by Preserving Epithelial Tight Junction Integrity.

BACKGROUND: Isoflurane may be protective in preclinical models of lung injury, but its use in patients with lung injury remains controversial and the mechanism of its protective effects remains unclear. The authors hypothesized that this protection is mediated at the level of alveolar tight junctions and investigated the possibility in a two-hit model of lung injury that mirrors human acute respiratory distress syndrome. METHODS: Wild-type mice were treated with isoflurane 1 h after exposure to nebulized endotoxin (n = 8) or saline control (n = 9) and then allowed to recover for 24 h before mechanical ventilation (MV; tidal volume, 15 ml/kg, 2 h) producing ventilator-induced lung injury. Mouse lung epithelial cells were similarly treated with isoflurane 1 h after exposure to lipopolysaccharide. Cells were cyclically stretched the following day to mirror the MV protocol used in vivo. RESULTS: Mice treated with isoflurane following exposure to inhaled endotoxin and before MV exhibited significantly less physiologic lung dysfunction. These effects appeared to be mediated by decreased vascular leak, but not altered inflammatory indices. Mouse lung epithelial cells treated with lipopolysaccharide and cyclic stretch and lungs harvested from mice after treatment with lipopolysaccharide and MV had decreased levels of a key tight junction protein (i.e., zona occludens 1) that was rescued by isoflurane treatment. CONCLUSIONS: Isoflurane rescued lung injury induced by a two-hit model of endotoxin exposure followed by MV by maintaining the integrity of the alveolar-capillary barrier possibly by modulating the expression of a key tight junction protein.