RESUMEN
Deficient wound healing is frequently observed in patients diagnosed with diabetes, a clinical complication that compromises mobility and leads to limb amputation, decreasing patient autonomy and family lifestyle. Fibroblasts are crucial for secreting the extracellular matrix (ECM) to pave the wound site for endothelial and keratinocyte regeneration. The biosynthetic pathways involved in collagen production and crosslinking are intimately related to fibroblast redox homeostasis. In this study, two sets of human dermic fibroblasts were cultured in normal (5 mM) and high (25 mM)-glucose conditions in the presence of 1 µM selenium, as sodium selenite (inorganic) and the two selenium amino acids (organic), Se-cysteine and Se-methionine, for ten days. We investigated the ultrastructural changes in the secreted ECM induced by these conditions using scanning electron microscopy (SEM). In addition, we evaluated the redox impact of these three compounds by measuring the basal state and real-time responses of the thiol-based HyPer biosensor expressed in the cytoplasm of these fibroblasts. Our results indicate that selenium compound supplementation pushed the redox equilibrium towards a more oxidative tone in both sets of fibroblasts, and this effect was independent of the type of selenium. The kinetic analysis of biosensor responses allowed us to identify Se-cysteine as the only compound that simultaneously improved the sensitivity to oxidative stimuli and augmented the disulfide bond reduction rate in high-glucose-cultured fibroblasts. The redox response profiles showed no clear association with the ultrastructural changes observed in matrix fibers secreted by selenium-treated fibroblasts. However, we found that selenium supplementation improved the ECM secreted by high-glucose-cultured fibroblasts according to endothelial migration assessed with a wound healing assay. Direct application of sodium selenite and Se-cysteine on purified collagen fibers subjected to glycation also improved cellular migration, suggesting that these selenium compounds avoid the undesired effect of glycation.
RESUMEN
RESUMEN Las úlceras por presión (UPP) y úlceras venosas (UV) son frecuentes en adultos y adultos mayores. En Chile un 70% de las heridas crónicas corresponden a UV y la prevalencia de UPP en pacientes hospitalizados es de 28%. El objetivo de esta revisión es analizar la evidencia disponible respecto al tratamiento nutricional de individuos con UPP y UV. Estas úlceras tienen diferentes etiologías, pero ambas provocan un aumento de requerimientos energéticos, proteicos y de micronutrientes. La cicatrización de heridas depende de varios factores como: el tipo de úlcera, estado nutricional, patologías presentes, el tipo de curación y el tratamiento médico. La terapia nutricional establece en la mantención o aumento de peso de estos pacientes, administración adecuada de proteínas y suplementación de energía, proteínas o micronutrientes cuando se presente déficit.
ABSTRACT Pressure and venous ulcers are common in adults and the elderly. In Chile, 70% of chronic wounds correspond to venous ulcers and the prevalence of pressure ulcers in hospitalized patients is 28%. The aim of this review was to analyze the available evidence regarding the nutritional treatment of individuals with pressure and venous ulcers. These ulcers have different etiologies, but both produce an increase in energy, protein, and micronutrient requirements. The healing of wounds depends on several factors such as the type of ulcer, nutritional status, current co-morbidities, healing type and medical treatment. Nutritional therapy should be based on weight maintenance or gain of these patients, adequate administration of proteins and energy supplementation, or protein or micronutrients when a deficiency occurs.