Browsing by Author "Del Rio, Rodrigo"

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    Ablation of brainstem C1 neurons improves cardiac function in volume overload heart failure
    (2019) Andrade Andrade, David Cristóbal; Toledo, Camilo; Díaz, Hugo S.; Lucero, Claudia; Arce Álvarez, Alexis; Oliveira, Luis M.; Takakura, Ana C.; Moreira, Thiago S.; Schultz, Harold D.; Del Rio, Rodrigo; Marcus, Noah J.; Alcayaga Urbina, Julio Andrés
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    Activation of Intra-nodose Ganglion P2X7 Receptors Elicit Increases in Neuronal Activity
    (2023) Alcayaga, Julio; Vera, Jorge; Reyna-Jeldes, Mauricio; Covarrubias, Alejandra A. A.; Coddou, Claudio; Diaz-Jara, Esteban; Del Rio, Rodrigo; Retamal, Mauricio A. A.
    Vagus nerve innervates several organs including the heart, stomach, and pancreas among others. Somas of sensory neurons that project through the vagal nerve are located in the nodose ganglion. The presence of purinergic receptors has been reported in neurons and satellite glial cells in several sensory ganglia. In the nodose ganglion, calcium depletion-induced increases in neuron activity can be partly reversed by P2X7 blockers applied directly into the ganglion. The later suggest a possible role of P2X7 receptors in the modulation of neuronal activity within this sensory ganglion. We aimed to characterize the response to P2X7 activation in nodose ganglion neurons under physiological conditions. Using an ex vivo preparation for electrophysiological recordings of the neural discharges of nodose ganglion neurons, we found that treatments with ATP induce transient neuronal activity increases. Also, we found a concentration-dependent increase in neural activity in response to Bz-ATP (ED50 = 0.62 mM, a selective P2X7 receptor agonist), with a clear desensitization pattern when applied every similar to 30 s. Electrophysiological recordings from isolated nodose ganglion neurons reveal no differences in the responses to Bz-ATP and ATP. Finally, we showed that the P2X7 receptor was expressed in the rat nodose ganglion, both in neurons and satellite glial cells. Additionally, a P2X7 receptor negative allosteric modulator decreased the duration of Bz-ATP-induced maximal responses without affecting their amplitude. Our results show the presence of functional P2X7 receptors under physiological conditions within the nodose ganglion of the rat, and suggest that ATP modulation of nodose ganglion activity may be in part mediated by the activation of P2X7 receptors.
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    Acute effects of high-intensity interval training session and endurance e8xercise on pulmonary function and cardiorespiratory coupling
    (2020) Andrade Andrade, David Cristóbal; Arce Álvarez, Alexis; Parada, Felipe; Uribe, Sebastián; Gordillo, Pamela; Dupré, Anita; Ojeda, Carla; Palumbo, Fiorella; Castro, Guillermo; Vásquez Muñoz, Manuel; Del Rio, Rodrigo; Ramírez Campillo, Rodrigo; Izquierdo, Mikel
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    Acute Effects of Systemic Erythropoietin Injections on Carotid Body Chemosensory Activity Following Hypoxic and Hypercapnic Stimulation
    (2018) Andrade Andrade, David Cristóbal; Iturriaga Agüera, Rodrigo; Jeton, Florine; Alcayaga Urbina, Julio Andrés; Voituron, Nicolas; Del Rio, Rodrigo
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    Arginase-endothelial nitric oxide synthase imbalance contributes to endothelial dysfunction during chronic intermittent hypoxia
    (2015) Krause Leyton, Bernardo; Del Rio, Rodrigo; Moya, Esteban A.; Marquez Gutiérrez, Mónica; Casanello Toledo, Paola Cecilia; Iturriaga Agüera, Rodrigo
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    Benefits of oxytocin administration in obstructive sleep apnea
    (2017) Jain, Vivek; Marbach, Joseph; Kimbro, Shawn; Andrade Andrade, David Cristóbal; Jain, Arad; Capozzi, Eleanor; Mele, Kyle; Del Rio, Rodrigo; Kay, Matthew W.; Mendelowitz, David
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    Carbamylated form of human erythropoietin normalizes cardiorespiratory disorders triggered by intermittent hypoxia mimicking sleep apnea syndrome
    (LIPPINCOTT WILLIAMS & WILKINS, 2021) Andrade, David C.; Toledo, Camilo; Diaz, Hugo S.; Pereyra, Katherin, V; Schwarz, Karla G.; Diaz Jara, Esteban; Melipillan, Claudia; Rios Gallardo, Angelica P.; Uribe Ojeda, Atenea; Alcayaga, Julio; Quintanilla, Rodrigo A.; Iturriaga, Rodrigo; Richalet, Jean Paul; Voituron, Nicolas; Del Rio, Rodrigo
    Background and objective: Chronic intermittent hypoxia (CIH), one of the main features of obstructive sleep apnea (OSA), enhances carotid body-mediated chemoreflex and induces hypertension and breathing disorders. The carbamylated form of erythropoietin (cEpo) may have beneficial effects as it retains its antioxidant/anti-inflammatory and neuroprotective profile without increasing red blood cells number. However, no studies have evaluated the potential therapeutic effect of cEpo on CIH-related cardiorespiratory disorders. We aimed to determine whether cEpo normalized the CIH-enhanced carotid body ventilatory chemoreflex, the hypertension and ventilatory disorders in rats. Methods: Male Sprague-Dawley rats (250 g) were exposed to CIH (5% O-2, 12/h, 8 h/day) for 28 days. cEPO (20 mu g/kg, i.p) was administrated from day 21 every other day for one more week. Cardiovascular and respiratory function were assessed in freely moving animals. Results: Twenty-one days of CIH increased carotid body-mediated chemoreflex responses as evidenced by a significant increase in the hypoxic ventilatory response (FiO2 10%) and triggered irregular eupneic breathing, active expiration, and produced hypertension. cEpo treatment significantly reduced the carotid body--chemoreflex responses, normalizes breathing patterns and the hypertension in CIH. In addition, cEpo treatment effectively normalized carotid body chemosensory responses evoked by acute hypoxic stimulation in CIH rats. Conclusion: Present results strongly support beneficial cardiorespiratory therapeutic effects of cEpo during CIH exposure.
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    Cardiorespiratory alterations following intermittent photostimulation of RVLM C1 neurons: Implications for long-term blood pressure, breathing and sleep regulation in freely moving rats
    (2022) Toledo, Camilo; Andrade, David C.; Diaz-Jara, Esteban; Ortolani, Domiziana; Bernal-Santander, Ignacio; Schwarz, Karla G.; Ortiz, Fernando C.; Marcus, Noah J.; Oliveira, Luiz M.; Takakura, Ana C.; Moreira, Thiago S.; Del Rio, Rodrigo
    Aim Sympathoexcitation and sleep-disordered breathing are common contributors for disease progression. Catecholaminergic neurons from the rostral ventrolateral medulla (RVLM-C1) modulate sympathetic outflow and have anatomical projections to respiratory neurons; however, the contribution of highly selective activation of RVLM-C1 neurons on long-term autonomic and breathing (dys)regulation remains to be understood. Methods To explore this relationship, a lentiviral vector carrying the light-sensitive cation channel channelrhodopsin-2 (LVV-PRSX8-ChR2-YFP) was unilaterally injected into the RVLM of healthy rats. On the contralateral side, LVV-PRSX8-ChR2-YFP was co-injected with a specific immunotoxin (D beta H-SAP) targeted to eliminate C1 neurons. Results Intermittent photostimulation of RVLM-C1 in vivo, in unrestrained freely moving rats, elicited long-term facilitation of the sympathetic drive, a rise in blood pressure and sympatho-respiratory coupling. In addition, photoactivation of RVLM-C1 induced long-lasting ventilatory instability, characterized by oscillations in tidal volume and increased breathing variability, but only during non-rapid eye movement sleep. These effects were not observed when photostimulation of the RVLM was performed in the presence of D beta H-SAP toxin. Conclusions The finding that intermittent activation of RVLM-C1 neurons induces autonomic and breathing dysfunction suggest that episodic stimulation of RVLM-C1 may serve as a pathological substrate for the long-term development of cardiorespiratory disorders.
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    Cardiovascular and autonomic dysfunction in long-COVID syndrome and the potential role of non-invasive therapeutic strategies on cardiovascular outcomes
    (2023) Allendes, Francisca J.; Diaz, Hugo S.; Ortiz, Fernando C.; Marcus, Noah J.; Quintanilla, Rodrigo; Inestrosa, Nibaldo C.; Del Rio, Rodrigo
    A significant percentage of COVID-19 survivors develop long-lasting cardiovascular sequelae linked to autonomic nervous system dysfunction, including fatigue, arrhythmias, and hypertension. This post-COVID-19 cardiovascular syndrome is one facet of "long-COVID," generally defined as long-term health problems persisting/appearing after the typical recovery period of COVID-19. Despite the fact that this syndrome is not fully understood, it is urgent to develop strategies for diagnosing/managing long-COVID due to the immense potential for future disease burden. New diagnostic/therapeutic tools should provide health personnel with the ability to manage the consequences of long-COVID and preserve/improve patient quality of life. It has been shown that cardiovascular rehabilitation programs (CRPs) stimulate the parasympathetic nervous system, improve cardiorespiratory fitness (CRF), and reduce cardiovascular risk factors, hospitalization rates, and cognitive impairment in patients suffering from cardiovascular diseases. Given their efficacy in improving patient outcomes, CRPs may have salutary potential for the treatment of cardiovascular sequelae of long-COVID. Indeed, there are several public and private initiatives testing the potential of CRPs in treating fatigue and dysautonomia in long-COVID subjects. The application of these established rehabilitation techniques to COVID-19 cardiovascular syndrome represents a promising approach to improving functional capacity and quality of life. In this brief review, we will focus on the long-lasting cardiovascular and autonomic sequelae occurring after COVID-19 infection, as well as exploring the potential of classic and novel CRPs for managing COVID-19 cardiovascular syndrome. Finally, we expect this review will encourage health care professionals and private/public health organizations to evaluate/implement non-invasive techniques for the management of COVID-19 cardiovascular sequalae.
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    Carotid body inflammation and cardiorespiratory alterations in intermittent hypoxia
    (2012) Del Rio, Rodrigo; Moya, Esteban A.; Parga, Maria J.; Madrid, Carlos; Iturriaga, Rodrigo
    Chronic intermittent hypoxia (CIH), a main feature of obstructive sleep apnoea (OSA), increases hypoxic ventilatory responses and elicits hypertension, partially attributed to an enhance carotid body (CB) responsiveness to hypoxia. As inflammation has been involved in CIH-induced hypertension and chemosensory potentiation, we tested whether ibuprofen may block CB chemosensory and cardiorespiratory alterations induced by CIH in a rat model of OSA.
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    Carotid Body Inflammation: Role in Hypoxia and in the Anti-inflammatory Reflex
    (AMER PHYSIOLOGICAL SOC, 2022) Iturriaga, Rodrigo; Del Rio, Rodrigo; Alcayaga, Julio
    Emergent evidence indicates that the carotid body (CB) chemoreceptor may sense systemic inflammatory molecules and is an afferent arm of the anti-inflammatory reflex. Moreover, a proinflammatory milieu within the CB is involved in the enhanced CB chemosensory responsiveness to oxygen following sustained and intermittent hypoxia. In this review, we focus on the physiopathological participation of CBs in inflammatory diseases, such as sepsis and intermittent hypoxia.
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    Carotid Body Type-I Cells Under Chronic Sustained Hypoxia: Focus on Metabolism and Membrane Excitability
    (2018) Pulgar-Sepulveda, Raul; Varas, Rodrigo; Iturriaga Agüera, Rodrigo; Del Rio, Rodrigo; Ortiz, Fernando C.
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    Chronic intermittent hypoxia promotes glomerular hyperfiltration and potentiates hypoxia-evoked decreases in renal perfusion and PO2
    (2023) Kious, Kiefer W.; Savage, Kalie A.; Twohey, Stephanie C. E.; Highum, Aubrey F.; Philipose, Andrew; Diaz, Hugo S.; Del Rio, Rodrigo; Lang, James A. A.; Clayton, Sarah C.; Marcus, Noah J.
    Introduction: Sleep apnea (SA) is highly prevalent in patients with chronic kidney disease and may contribute to the development and/or progression of this condition. Previous studies suggest that dysregulation of renal hemodynamics and oxygen flux may play a key role in this process. The present study sought to determine how chronic intermittent hypoxia (CIH) associated with SA affects regulation of renal artery blood flow (RBF), renal microcirculatory perfusion (RP), glomerular filtration rate (GFR), and cortical and medullary tissue PO2 as well as expression of genes that could contribute to renal injury. We hypothesized that normoxic RBF and tissue PO2 would be reduced after CIH, but that GFR would be increased relative to baseline, and that RBF, RP, and tissue PO2 would be decreased to a greater extent in CIH vs. sham during exposure to intermittent asphyxia (IA, FiO2 0.10/FiCO2 0.03). Additionally, we hypothesized that gene programs promoting oxidative stress and fibrosis would be activated by CIH in renal tissue.Methods: All physiological variables were measured at baseline (FiO2 0.21) and during exposure to 10 episodes of IA (excluding GFR).Results: GFR was higher in CIH-conditioned vs. sham (p < 0.05), whereas normoxic RBF and renal tissue PO2 were significantly lower in CIH vs. sham (p < 0.05). Reductions in RBF, RP, and renal tissue PO2 during IA occurred in both groups but to a greater extent in CIH (p < 0.05). Pro-oxidative and pro-fibrotic gene programs were activated in renal tissue from CIH but not sham.Conclusion: CIH adversely affects renal hemodynamic regulation and oxygen flux during both normoxia and IA and results in changes in renal tissue gene expression.
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    Chronic intermittent hypoxia-induced vascular enlargement and VEGF upregulation in the rat carotid body is not prevented by antioxidant treatment
    (2011) Del Rio, Rodrigo; Munoz, Cristian; Arias, Paulina; Court, Felipe A.; Moya, Esteban A.; Iturriaga, Rodrigo
    Del Rio R, Munoz C, Arias P, Court FA, Moya EA, Iturriaga R. Chronic intermittent hypoxia-induced vascular enlargement and VEGF upregulation in the rat carotid body is not prevented by antioxidant treatment. Am J Physiol Lung Cell Mol Physiol 301: L702-L711, 2011. First published August 5, 2011; doi:10.1152/ajplung.00128.2011.-Chronic intermittent hypoxia (CIH), a characteristic of sleep obstructive apnea, enhances carotid body (CB) chemosensory responses to hypoxia, but its consequences on CB vascular area and VEGF expression are unknown. Accordingly, we studied the effect of CIH on CB volume, glomus cell numbers, blood vessel diameter and number, and VEGF immunoreactivity (VEGF-ir) in male Sprague-Dawley rats exposed to 5% O-2, 12 times/h for 8 h or sham condition for 21 days. We found that CIH did not modify the CB volume or the number of glomus cells but increased VEGF-ir and enlarged the vascular area by increasing the size of the blood vessels, whereas the number of the vessels was unchanged. Because oxidative stress plays an essential role in the CIH-induced carotid chemosensory potentiation, we tested whether antioxidant treatment with ascorbic acid may impede the vascular enlargement and the VEGF upregulation. Ascorbic acid, which prevents the CB chemosensory potentiation, failed to impede the vascular enlargement and the increased VEGF-ir. Thus present results suggest that the CB vascular enlargement induced by CIH is a direct effect of intermittent hypoxia and not secondary to the oxidative stress. Accordingly, the subsequent capillary changes may be secondary to the mechanisms involved in the neural chemosensory plasticity induced by intermittent hypoxia.
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    Chronic phenytoin treatment reduces rat carotid body chemosensory responses to acute hypoxia
    (2016) Alcayaga Urbina, Julio Andrés; Oyarce, María Paz; Del Rio, Rodrigo
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    Dendrochronological Analysis of Pinus pinea in Central Chile and South Spain for Sustainable Forest Management
    (2024) Loewe-Munoz, Veronica; Cachinero-Vivar, Antonio M.; Camarero, Jesus Julio; Del Rio, Rodrigo; Delard, Claudia; Navarro-Cerrillo, Rafael M.
    Pinus pinea is an important Mediterranean species due to its adaptability and tolerance to aridity and its high-quality pine nuts. Different forest types located in Mediterranean native and non-native environments provide the opportunity to perform comparative studies on the species' response to climate change. The aims of this study were to elucidate growth patterns of the species growing in native and exotic habitats and to analyze its response to climatic fluctuations, particularly drought, in both geographical contexts. Understanding stone pine (Pinus pinea) growth responses to climate variability in native and exotic habitats by comparing natural stands and plantations may provide useful information to plan adequate management under climate change. By doing so, we enhance the understanding of P. pinea's adaptability and provide practical approaches to its sustainable management. In this study, we reconstructed and compared the stem radial growth of seven stone pine stands, two in southern Spain and five in central-southern Chile, growing under different climatic conditions. We quantified the relationships between growth variability and climate variables (total rainfall, mean temperature, and SPEI drought index). Growth was positively correlated with autumn rainfall in plantations and with autumn-winter rainfall in natural stands. Growth was also enhanced by high autumn-to-spring rainfall in the driest Chilean plantation, whereas in the wettest and coolest plantation, such correlation was found in winter and summer. A negative impact of summer temperature was found only in one of the five Chilean plantations and in a Spanish site. The correlation between SPEI and tree-ring width indices showed different patterns between and within countries. Overall, exotic plantations showed lower sensitivity to climate variability than native stands. Therefore, stone pine plantations may be useful to assist in mitigating climate change.
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    Designing and implementing a test for measuring critical thinking in primary school
    (2016) Gelerstein, Damián; Del Rio, Rodrigo; Nussbaum Voehl, Miguel; Chiuminatto, Pablo; Ximena, López
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    Effect of thinning on growth and shape of Castanea sativa adult tree plantations for timber production in Chile
    (2023) Benedetti-Ruiz, Susana; Loewe-Munoz, Veronica; Del Rio, Rodrigo; Delard, Claudia; Barrales, Luis; Balzarini, Monica
    Chestnut (Castanea sativa Mill.) is an interesting species for high-quality timber production. It is well known that the species responds to early thinning, but there is no information on the impact of late interventions. The objective of this study was to assess the effect of a late thinning on the performance of unmanaged adult chestnut plantations in Chile. Future-tree selective thinning and control were compared in adult plantations using a randomized complete block design with three replicates at three sites, Minas, Pillo-Pillo and Pumillahue. Tree growth was evaluated periodically during the first 7 years after thinning in all plantations. Additionally, almost 20 years after the intervention, the Pumillahue plantation was measured for growth and tree shape variables. In this case study, the effect of thinning on tree growth decreased considerably after 5 years, with a maximum DBH increment in the third year after the intervention (45.8 %, 68.6 %, and 42.2 % in Minas, Pillo-Pillo and Pum-illahue, respectively). In all plantations, basal area was smaller in the thinned plots in the first years after the intervention, but in Pumillahue, 19 years after thinning, no differences were found among treatments. Height was statistically greater under thinning seven years after the intervention; this effect was also found in Pum-illahue plantation 19 years after thinning. Most trees showed high vigor, and were straight and healthy, even in control plots. Late effect of thinning was observed 19 years after thinning on tree shape, with a reduction in the proportion of bifurcated trees from 16 % to 8 %. The results suggest that late thinning is an effective silvicultural intervention to produce high-quality chestnut timber in unmanaged adult plantations. Progressive and frequent thinning should be used to increase growth and improve timber production in chestnut.
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    Effects of fertilization on radial growth of Pinus pinea explored hourly using dendrometers
    (2024) Loewe Muñoz, Veronica Francisca; Del Rio, Rodrigo; Delard Rodriguez, Claudia; Balzarini, Mónica
    Background: Stone pine (Pinus pinea), a drought-resistant species, has significant socio-economic benefits and increasing interest for the establishment of productive plantations in several countries, especially in a climate change context. Monitoring hourly stem diameter variations contributes to the understanding of the tree-growth response to changes in environmental conditions and management. By monitoring the diameter expansion of tree stems, high-resolution band dendrometers were used to study the development of adult trees growing in a semi-arid coastal environment of central Chile under fertilized and non-fertilized soil conditions through the span of a year. Results: Short cycles (< 21 h) were few in fertilized and non-fertilized trees (6 and 4, respectively), whereas long cycles (> 28 h) occurred at a higher frequency in fertilized trees (16 vs 6). Most of the circadian cycles were regular (24 ± 3 h). The longest cycle duration (59 h) was observed in fertilized trees during spring. In all seasons, each phase of the circadian cycle, especially during the stem diameter increment phase (P3, irreversible growth), started earlier in fertilized than in control trees. P3 duration was significantly longer in fertilized than in control trees in springtime. The maximum shrinkage (P1) was observed in summer for both treatments. Stem diameter increased faster in fertilized than in control trees throughout the year, with the highest accumulation occurring in spring and the lowest in autumn. The daily variability pattern showed lower growth under high temperature across seasons. Conclusions: This study highlights the importance of fertilization in enhancing stone pine diameter growth. This cultural practice should be further explored to contribute to the mitigation of climate change effects in semi-arid environments.
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    ELECTRODES MODIFIED BY Π STACKING OF METALLIC PHTHALOCYANINES AND ITS ELECTROCATALYTIC ACTIVITY ON NITRITE OXIDATION
    (2013) Navarrete, Natalia; Canales, Camila; Del Rio, Rodrigo; Ramirez, Galo
    In this work, it proposed the developing of a new material, a modified electrode with metallic phthalocyanines stacking columns, MxPc (Mx = Co, Fe and Ni), assembled by p interactions, which have a behavior as a supramolecular system. These electrodes showed an important electrocatalytic activity against nitrite oxidation, compared to the same complexes monomer multilayers adsorbed on the electrode (M-MxPc). It is proposed two new obtaining methods of these systems, S1-MxPc, where the complexes would form a column and would be coordinated with the surface electrode through a covalent bond of 4-aminopyridine (4-AP), and S2-MxPc, where the own functional groups of glassy carbon (GC) would be the covalent unions able to coordinate the complexes and the columns formation. These covalent unions between the electrode surface and phthalocyanines, would give a directional stacking, and therefore, would modify both its electrocatalytical activity and its electrical features.