title: Aging Selectively Modulates Vitamin C Transporter Expression Patterns in the Kidney.
abstract: In the kidney, vitamin C is reabsorbed from the glomerular ultrafiltrate by sodium-vitamin C cotransporter isoform 1 (SVCT1) located in the brush border membrane of the proximal tubules. Although we know that vitamin C levels decrease with age, the adaptive physiological mechanisms used by the kidney for vitamin C reabsorption during aging remain unknown. In this study, we used an animal model of accelerated senescence (SAMP8 mice) to define the morphological alterations and aging-induced changes in the expression of vitamin C transporters in renal tissue. Aging induced significant morphological changes, such as periglomerular lymphocytic infiltrate and glomerular congestion, in the kidneys of SAMP8 mice, although no increase in collagen deposits was observed using 2-photon microscopy analysis and second harmonic generation. The most characteristic histological alteration was the dilation of intracellular spaces in the basolateral region of proximal tubule epithelial cells. Furthermore, a combination of laser microdissection, qRT-PCR, and immunohistochemical analyses allowed us to determine that SVCT1 expression specifically increased in the proximal tubules from the outer strip of the outer medulla (segment S3) and cortex (segment S2) during aging and that these tubules also express GLUT1. We conclude that aging modulates vitamin C transporter expression and that renal over-expression of SVCT1 enhances vitamin C reabsorption in aged animals that may synthesize less vitamin C. J. Cell. Physiol. 232: 2418-2426, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Centro de Microscopía Avanzada, CMA BIO BIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.|Departamento de Nutrición y Dietética, Facultad de Farmacia, Universidad de Concepción, Concepción, Chile.
authors.forename: Katherine
authors.initials: K
authors.lastname: Forman
authors.affiliation: Centro de Microscopía Avanzada, CMA BIO BIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Fernando
authors.initials: F
authors.lastname: Martínez
authors.affiliation: Departamento de Biología Celular, Génetica y Fisiología, Laboratorio de Fisiología Animal, Facultad de Ciencias, Centro de Investigaciones Biomédicas en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Universidad de Málaga, Málaga, España.
authors.forename: Manuel
authors.initials: M
authors.lastname: Cifuentes
authors.affiliation: Centro de Microscopía Avanzada, CMA BIO BIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Romina
authors.initials: R
authors.lastname: Bertinat
authors.affiliation: Centro de Microscopía Avanzada, CMA BIO BIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Katterine
authors.initials: K
authors.lastname: Salazar
authors.affiliation: Centro de Microscopía Avanzada, CMA BIO BIO, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Nualart
mesh_terms: D000222:Adaptation, Physiological; D000367:Age Factors; D000375:Aging / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism*; D016922:Cellular Senescence; D051272:Glucose Transporter Type 1 / Q000235:genetics / Q000378:metabolism; D007668:Kidney / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008807:Mice, Inbred BALB C; D023421:Models, Animal; D065608:Renal Reabsorption; D060347:Sodium-Coupled Vitamin C Transporters / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D051272:Glucose Transporter Type 1; C555164:Slc23a1 protein, mouse; C495678:Slc2a1 protein, mouse; D060347:Sodium-Coupled Vitamin C Transporters; D001205:Ascorbic Acid