Browsing by Author "Salazar, Esteban"

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    Fetal Programming of Renal Dysfunction and High Blood Pressure by Chronodisruption
    (2019) Mendez, Natalia; Torres-Farfan, Claudia; Salazar, Esteban; Bascur, Pia; Bastidas, Carla; Vergara, Karina; Spichiger, Carlos; Halabi, Diego; Vio, Carlos P.; Richter, Hans G.
    Adverse prenatal conditions are known to impose significant trade-offs impinging on health and disease balance during adult life. Among several deleterious factors associated with complicated pregnancy, alteration of the gestational photoperiod remains largely unknown. Previously, we reported that prenatal manipulation of the photoperiod has adverse effects on the mother, fetus, and adult offspring; including cardiac hypertrophy. Here, we investigated whether chronic photoperiod shifting (CPS) during gestation may program adult renal function and blood pressure regulation. To this end, pregnant rats were subjected to CPS throughout pregnancy to evaluate the renal effects on the fetus and adult offspring. In the kidney at 18 days of gestation, both clock and clock-controlled gene expression did not display a daily pattern, although there were recurrent weaves of transcriptional activity along the 24 h in the control group. Using DNA microarray, significant differential expression was found for 1,703 transcripts in CPS relative to control fetal kidney (835 up-regulated and 868 down-regulated). Functional genomics assessment revealed alteration of diverse gene networks in the CPS fetal kidney, including regulation of transcription, aldosterone-regulated Na+ reabsorption and connective tissue differentiation. In adult offspring at 90 days of age, circulating proinflammatory cytokines IL-1 beta and IL-6 were increased under CPS conditions. In these individuals, CPS did not modify kidney clock gene expression but had effects on different genes with specific functions in the nephron. Next, we evaluated several renal markers and the response of blood pressure to 4% NaCl in the diet for 4 weeks (i.e., at 150 days of age). CPS animals displayed elevated systolic blood pressure in basal conditions that remained elevated in response to 4% NaCl, relative to control conditions. At this age, CPS modified the expression of Nhe3, Ncc, Atp1a1, Nr3c1 (glucocorticoid receptor), and Nr3c2 (mineralocorticoid receptor); while Nkcc, Col3A1, and Opn were modified in the CPS 4%+NaCl group. Furthermore, CPS decreased protein expression of Kallikrein and COX-2, both involved in sodium handling. In conclusion, gestational chronodisruption programs kidney dysfunction at different levels, conceivably underlying the prehypertensive phenotype observed in the adult CPS offspring.
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    Unravelling geological controls on groundwater flow and surface water-groundwater interaction in mountain systems: A multi-disciplinary approach
    (ELSEVIER, 2023) Marti, Etienne Bernard Christian; Leray, Sarah Tiphaine Lucile; Villela, Daniela; Maringue Canales, José Ignacio; Yañez Morroni, Gonzalo José; Salazar, Esteban; Poblete, Fernando; Jiménez, Jose; Reyes, Gabriela; Poblete Farias, Guillermo Hernán; Huaman Sevilla, Zeidy Lisseth; Figueroa González, Ronny Javier; Araya Vargas, Jaime Andrés; Sanhueza, Jorge; Muñoz, Marjorie; Charrier, Reynaldo; Fernández, Gabriel
    Mountain water resources are considered to be the world's water towers. Still, despite their importance for downstream societies and ecosystems and their vulnerability to climate change, they remain poorly understood - It is the case in particular of mountain groundwater systems. Their complexity makes them difficult to conceptualize, while their remoteness makes them difficult to study, both observationally and instrumentally. Understanding mountain hydrogeological systems is mostly limited by the lack of characterization of the subsurface geologic framework and by the limited understanding of the role of geological structures on groundwater flow and on surface water-groundwater interaction. Removing methodological barriers is therefore a necessary step for improving the understanding of mountain hydrogeological systems. To tackle this problem, we develop a comprehensive multi-disciplinary approach to gain insights into the hydrogeological role of geological structures in ungauged mountain catchments. The methodology consists of several complementary methods: (1) geological mapping at multiple scales; (2) a geophysical study including on ground Electrical Resistivity Tomography (ERT) and, gravimetry transects, and a UAV-based magnetic survey; (3) hydraulic data, including a 9 km long transect of streamflow measurements in the recession period, the longterm Normalized Difference Vegetation Index (NDVI), and varied hydric markers (e.g., a thermal spring and a puddle). The methodology is tested in the Parque Nacional del Rio Clarillo, an ungauged catchment in the Andes Mountains (& AP;130 km2) that is illustrative of the complexity of mountain hydrosystems featuring fault zones, weathered zones, intrusive rocks, and volcano-sedimentary successions.An increase of approximately 50% in the streamflow is observed over a short distance of 1 km. Such a localized and significant increase in the baseflow is not related to any superficial supply and can only be explained by groundwater exfiltration. Based on the multiscale geological mapping and geophysical survey, a regional N-S fault and a secondary set of E-W local faults are identified in the vicinity of the resurgence area, which conjointly are likely to export groundwater from a neighbouring subcatchment up to the resurgence area. Downstream of the resurgence area, no significant change in the baseflow is observed, corresponding to the presence of an impermeable granitic pluton identified by the geological and geophysical mapping. Finally, a fractured zone in the Andean foothills is identified in the volcanic unit, which coincides with a perennial thermal spring, indicating upwelling flow and hydrogeological connectivity between the mountain block and the alluvial basin.The results strongly support the ability of the proposed methodology to identify geological structures that substantially impact the evolution of the baseflow through the catchment. The complementary multi-disciplinary methods are used innovatively to infer the link between geological and hydrogeological structures. The methodology does not aim to fully characterize the geological framework of the catchment but pragmatically focuses on hydrogeologically pertinent structures that may impact baseflow and consequently catchment management.