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FUNCIONES DE LA VITAMINA C EN EL METABOLISMO DEL COLÁGENO

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  • National Institute of Hygiene, Epidemiology and Microbiology, Cuba

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RESUMEN La mayoría de los mamíferos son capaces de sintetizar vitamina C, pero algunas especies como el hombre son dependientes de fuentes exógenas de esta vitamina porque carecen de la última enzima en la biosíntesis del ácido ascórbico a partir de la glucosa. Su principal función es como agente reductor en diferentes reacciones en el metabolismo del colágeno. Su deficiencia se asocia fundamentalmente con una disminución en la síntesis de procolágeno y con una reducida hidroxilación de los residuos prolina y lisina, obteniéndose una molé-cula menos estable a la temperatura corporal. En animales de laboratorio con carencia de esta vitamina se observó una disminución en la formación de residuos hidroxilisina en hueso, y por tanto, una reducción en la proporción pyridinolina (Pyd)/deoxypyridinolina (Dpd) en hueso y orina. Recientemente se han encontrado afectaciones similares en humanos. Descriptores DeCS: COLAGENO/metabolismo;ACIDO ASCORBICO/fisiología. 1 Licenciada en Química. La vitamina C (ácido ascórbico) es un nutriente esencial de la dieta del hombre y otras pocas especies que carecen de la enzi-ma L-glucono-g lactanoa oxidasa (EC 1.1.3.8), que es la última enzima en la biosíntesis del ácido ascórbico a partir de la glucosa. 1 La deficiencia de esta vitamina está asociada fundamentalmente con la carencia de tejido conectivo. La síntesis de colágeno es un proceso complejo de síntesis de proteína, modifica-ciones postraduccionales, secreción de pro-teínas y formación de la matriz extracelular. Muchos de estos pasos se afectan con las va-riaciones de vitamina C en la dieta (fig. 1). 2
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... En el escorbuto el problema se produce en la síntesis del colágeno, ya que el AA es un cofactor esencial en este proceso (18). La deficiencia de AA se asocia con una disminución en la síntesis de pro-colágeno y con una reducida hidroxilación de los residuos prolina y lisina, obteniéndose una molécula menos estable a la temperatura corporal. ...
... El AA facilita la absorción del hierro en el tracto di-gestivo y regula la distribución y almacenamiento del mismo. El ascorbato (AH -), forma químicamente estable a pH fisiológico, es un gran agente reductor hidrosoluble debido a sus dos hidroxilos (OH -) ionizables capaces de "limpiar" a los tejidos de las ERO responsables del stress oxidativo (18) (20). A pesar de que en las vías degradativas del AA se producen EROs, no se ha demostrado que estas especies participen en procesos de oxidación ni peroxidación que sean perjudiciales (21). ...
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Vitamin C or L-ascorbic acid (AA) is an essential vitamin and a water soluble important antioxidant agent, chemically synthesized from glucose, by enzymatic reactions, being the L-gulono -gamma-lactone oxidase (GLO) the last enzyme involved. The inability to synthesize AA by some species, due to the absence of GLO seems to have happened hundreds of millions years ago. The degradation of the AA is carried out by oxidative processes which involve the hydrolysis of the lactona ring to produce 2,3-diketogulonic acid (DCG) that is later degraded by decarboxilation, generating colored products, found in some ocular pathologies. Among the different properties of the AA, it is worth mentioning its capacity to absorb ultraviolet radiation (RUV) and to avoid the photochemical damage of exposed. tissues. In humans and in some animals (guinea pigs, primates, etc) the aqueous humor has bigger concentrations of AA than plasma. This responds to a mechanism of specialized active transport in the ciliary body that transfers AA from the blood towards the aqueous humor and from there to the corneal epithelium, transforming the cornea into the structure of the eye responsible for the biggest absorption of RUV.
... En el escorbuto el problema se produce en la síntesis del colágeno, ya que el AA es un cofactor esencial en este proceso (18). La deficiencia de AA se asocia con una disminución en la síntesis de pro-colágeno y con una reducida hidroxilación de los residuos prolina y lisina, obteniéndose una molécula menos estable a la temperatura corporal. ...
... El ascorbato (AH -), forma químicamente estable a pH fisiológico, es un gran agente reductor hidrosoluble debido a sus dos hidroxilos (OH -) ionizables capaces de "limpiar" a los tejidos de las especies reactivas del oxígeno (ERO) responsables del stress oxidativo (18) (20). A pesar de que en las vías degradativas del AA se producen EROs, no se ha demostrado que estas especies participen en procesos de oxidación ni peroxidación que sean perjudiciales (21). ...
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La Vitamina C o ácido L-ascórbico (AA), es una vitamina esencial y un importante agente antioxidante hidrosoluble, que se sintetiza químicamente a partir de la glucosa, mediante una serie de reacciones enzimáticas, siendo la L-gulono-g-lactona oxidasa (GLO) la última enzima involucrada. La incapacidad de sintetizar AA por ausencia de GLO ocurrió hace cientos de millones de años y se manifiesta sólo en algunas especies. La degradación del AA se lleva a cabo mediante procesos oxidativos que involucran la hidrólisis del anillo lactona para producir ácido 2,3-dicetogulónico (DCG), que posteriormente se degrada por decarboxilación, generando productos coloreados, encontrados en algunas patologías oculares. Entre las diferentes propiedades del AA cabe mencionar su capacidad de absorber radiación ultravioleta (RUV) y evitar el daño fotoquímico en órganos expuestos. En humanos, y en algunos animales (cobayos, ciertos primates, etc.) el humor acuoso tiene mayor concentración de AA que el plasma. Esto responde a un mecanismo de transporte activo especializado en el cuerpo ciliar que se encarga de transportar el AA desde la sangre hacia el humor acuoso y desde allí al epitelio corneal, transformando a la córnea en la estructura del ojo responsable de la mayor absorción de RUV.
... Among the vitamins, the most accumulated evidence in tendon repair processes corresponds to vitamins C and D. Vitamin C is instrumental due to its antioxidant properties and its action as a coenzyme in collagen synthesis through the hydroxyla-tion of proline and lysine to hydroxyproline and hydroxylysinerespectively. Both hy-droxylated amino acids are essential for collagen structure and tendon function [28,64,65]. Thus, vitamin C deficiency is associated with a decrease in the synthesis of procollagen, due to a lower hydroxylation of proline and lysine residues [66,67]. ...
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Physical activity in general and sports in particular, is a mechanism that produces stress and generates great force in the tendon and in the muscle-tendon unit, which increases the risk of injury (tendinopathies). Eccentric and repetitive contraction of the muscle precipitates persistent microtraumatism in the tendon unit. In the development of tendinopathies, the cellular process includes inflammation, apoptosis, vascular, and neuronal changes. Currently, treatments with oral supplements are frequently used. Curcumin seems to preserve, and even repair, damaged tendons. In this systematic review, we focus more especially on the benefits of curcumin. The biological actions of curcumin are diverse, but act around three systems: (a) inflammatory, (b) nuclear factor B (NF-κB) related apoptosis pathways, and (c) oxidative stress systems. A bibliographic search is conducted under the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) as a basis for reporting reliable systematic reviews to perform a Scoping review. After analysing the manuscripts, we can conclude that curcumin is a product that demonstrates a significant biological antialgic, anti-inflammatory, and antioxidant power. Therefore, supplementation has a positive effect on the inflammatory and regenerative response in tendinopathies. In addition, curcumin decreases and modulates the cell infiltration, activation, and maturation of leukocytes, as well as the production of pro-inflammatory mediators at the site of inflammation.
... On the other hand, VC deficiency is associated with decreased procollagen synthesis and reduced hydroxylation of proline and lysine residues [63,64]. In studies in guinea pigs, proline hydroxylation in articular cartilage has been shown to be especially resistant to ascorbate deficiency [65]. ...
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... Además, Rojas y su equipo encontraron una cantidad significativa de ácido ascórbico en el extracto hidroalcohólico (136,63 mg/100 g extracto) siendo esto uno de los posibles factores que influyeron en la actividad promotora de colágeno, ya que se ha encontrado que la vitamina C produce un incremento en la transcripción, traducción y estabilidad del ARNm del procolágeno (Basabe, 2000). ...
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... El mango de hilacha es uno de los frutos de más amplio cultivo en la costa norte colombiana, con un contenido promedio de 35 mg/100g de vitamina C (Mendoza-Corvis, 2014). La mayoría de los mamíferos son capaces de sintetizarla, pero algunas especies como el hombre son dependientes de fuentes exógenas de ésta, porque carecen de la última enzima en la biosíntesis del ácido ascórbico a partir de la glucosa (Babase, 2000), la L-gulonalactona oxidasa (Leong & Oey, 2012). La vitamina C ayuda a prevenir el cáncer, escorbuto, enfermedades cardiovasculares y mejora la absorción de hierro para prevenir la anemia (Leong & Oey, 2012;Amer et al., 2002). ...
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