Universidad del Desarrollo

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Sustained Energy Deficit Following Perinatal Asphyxia: A Shift towards the Fructose-2,6-bisphosphatase (TIGAR)-Dependent Pentose Phosphate Pathway and Postnatal Development
(2021)
Carolyne Lespay-Rebolledo
;
Andrea Tapia-Bustos
;
Ronald Perez-Lobos
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Valentina Vio
;
Emmanuel Casanova-Ortiz
<jats:p>Labor and delivery entail a complex and sequential metabolic and physiologic cascade, culminating in most circumstances in successful childbirth, although delivery can be a risky episode if oxygen supply is interrupted, resulting in perinatal asphyxia (PA). PA causes an energy failure, leading to cell dysfunction and death if re-oxygenation is not promptly restored. PA is associated with long-term effects, challenging the ability of the brain to cope with stressors occurring along with life. We review here relevant targets responsible for metabolic cascades linked to neurodevelopmental impairments, that we have identified with a model of global PA in rats. Severe PA induces a sustained effect on redox homeostasis, increasing oxidative stress, decreasing metabolic and tissue antioxidant capacity in vulnerable brain regions, which remains weeks after the insult. Catalase activity is decreased in mesencephalon and hippocampus from PA-exposed (AS), compared to control neonates (CS), in parallel with increased cleaved caspase-3 levels, associated with decreased glutathione reductase and glutathione peroxidase activity, a shift towards the TIGAR-dependent pentose phosphate pathway, and delayed calpain-dependent cell death. The brain damage continues long after the re-oxygenation period, extending for weeks after PA, affecting neurons and glial cells, including myelination in grey and white matter. The resulting vulnerability was investigated with organotypic cultures built from AS and CS rat newborns, showing that substantia nigra TH-dopamine-positive cells from AS were more vulnerable to 1 mM of H2O2 than those from CS animals. Several therapeutic strategies are discussed, including hypothermia; N-acetylcysteine; memantine; nicotinamide, and intranasally administered mesenchymal stem cell secretomes, promising clinical translation.</jats:p>
1Scopus© Citations 5
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Improving Cell Recovery: Freezing and Thawing Optimization of Induced Pluripotent Stem Cells
(2022)
Markus Uhrig
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EZQUER, EDUARDO FERNANDO
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EZQUER, EDUARDO MARCELO
<jats:p>Achieving good cell recovery after cryopreservation is an essential process when working with induced pluripotent stem cells (iPSC). Optimized freezing and thawing methods are required for good cell attachment and survival. In this review, we concentrate on these two aspects, freezing and thawing, but also discuss further factors influencing cell recovery such as cell storage and transport. Whenever a problem occurs during the thawing process of iPSC, it is initially not clear what it is caused by, because there are many factors involved that can contribute to insufficient cell recovery. Thawing problems can usually be solved more quickly when a certain order of steps to be taken is followed. Under optimized conditions, iPSC should be ready for further experiments approximately 4–7 days after thawing and seeding. However, if the freezing and thawing protocols are not optimized, this time can increase up to 2–3 weeks, complicating any further experiments. Here, we suggest optimization steps and troubleshooting options for the freezing, thawing, and seeding of iPSC on feeder-free, Matrigel™-coated, cell culture plates whenever iPSC cannot be recovered in sufficient quality. This review applies to two-dimensional (2D) monolayer cell culture and to iPSC, passaged, frozen, and thawed as cell aggregates (clumps). Furthermore, we discuss usually less well-described factors such as the cell growth phase before freezing and the prevention of osmotic shock during thawing.</jats:p>
6Scopus© Citations 34
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Oxidative Stress Markers in COPD Patients Admitted to Pulmonary Rehabilitation
(2021)
Carolina Romero
;
Rodrigo L. Castillo
<jats:sec> <jats:title>Background:</jats:title> <jats:p>Chronic obstructive pulmonary disease (COPD) is a pathology, which leads to an irreversible and progressive reduction of the airflow, usually caused by smoking, but only present in 25% of smokers. Some mechanisms involved in the onset and progression of the disease are local and systemic factors such as inflammation, exacerbated immune response and the appearance of oxidative stress. For all these reasons, the use of oxidative stress parameters as progression markers or even as a way to monitor the response of any kind of non-pharmacological interventions, like the use of pulmonary rehabilitation (PR), is feasible.</jats:p> </jats:sec> <jats:sec> <jats:title>Aims:</jats:title> <jats:p>The study aims to determine markers of oxidative stress levels in plasma and erythrocytes in patients with COPD through the application of a PR protocol.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods:</jats:title> <jats:p>The study included 25 patients diagnosed with COPD according to the GOLD criteria with a medical indication of PR and attendance at the gym in San José Hospital, Santiago, Chile. Blood samples were obtained before the start of the protocol, in the 10<jats:sup>th</jats:sup> session, and at the end of the protocol (20<jats:sup>th</jats:sup> session). These samples were stored for oxidative stress determinations: FRAP (ferric reducing ability of plasma), F2-isoprostanes, reduced (GSH)/oxidized (GSSG) ratio and antioxidant enzyme activity in the erythrocyte. In all stages, associations between events and clinical parameters in patients have been observed. The clinical parameters assessed were the six-minute walking test (6MWT), maximal inspiratory and expiratory pressure, the BODE index and Saint George’s respiratory questionnaire, which includes quality of life.</jats:p> </jats:sec> <jats:sec> <jats:title>Results:</jats:title> <jats:p>The intracellular and extracellular capacity (GSH/GSSG and FRAP) in patients in PR at the 10<jats:sup>th</jats:sup> session were 53.1 and 34% higher than basal values, respectively. Only the GSH/GSSG ratio was 38.2% lower at the 20<jats:sup>th</jats:sup> session, related in part with higher plasma and erythrocyte lipid peroxidation at baseline. This could be due to the high concentration of reactive oxygen species in the first sessions, which has been reported in the literature as the acute effect of controlled exercise. Blood lipid peroxidation was 43.34 and 58.34% lower at the 10<jats:sup>th</jats:sup> and 20<jats:sup>th</jats:sup> sessions, respectively, demonstrating the improvements in the oxidative parameters with long-term exercise. With respect to oxidative enzyme activity, superoxide dismutase and catalase showed higher values of activity at the 10th and 20th sessions compared to the baseline. In the clinical parameters of the PR, significant changes were found in the BODE index and Saint George’s questionnaire, with these results being associated with a less predictive mortality score and a better understanding of the disease. This may be because the patients achieved longer distances in the 6MWT and better understood the disease at the end of the PR.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusion:</jats:title> <jats:p>The goal of this study was to contribute to the pathophysiological basis for further research on COPD patients, a disease of high prevalence in Chile. This study could support the basis for non-pharmacological strategies such a PR.</jats:p> </jats:sec>
2Scopus© Citations 1
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Acquisition, Maintenance and Relapse-Like Alcohol Drinking: Lessons from the UChB Rat Line
(2017)
Yedy Israel
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Eduardo Karahanian
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EZQUER, EDUARDO FERNANDO
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Paola Morales
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EZQUER, EDUARDO MARCELO
Scopus© Citations 28 1

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