RESUMEN
BACKGROUND AND OBJECTIVE: The formation of reactive oxygen species (ROS) is associated with cardiovascular disease (CVD). High dietary cholesterol can significantly alter the delicate balance between pro-oxidation and antioxidant defences leading to reactive oxygen species formation in the vasculature, without significant structural changes in tissue composition. We aimed to establish a methodology for the noninvasive assessment of skin fluorescent biomarkers in mice. MATERIALS AND METHODS: C57/black/6 wild-type (WT; n = 25) male mice were subdivided to receive normal rodent chow (n = 11) or a high cholesterol diet (2% cholesterol; n = 14) for 20 weeks. Skin autofluorescence measurements were made on the backs of anaesthetized (1.5-2% isoflurane in oxygen) mice. A laser probe was used to make simultaneous measurements of: collagen, elastin, nicotinamide pyridoxine, flavins, lipofuscin and ß-carotene. Results are expressed as group mean in arbitrary units (AU) ± standard error (SE). Hearts were excised and weighed (mg); cardiac hypertrophy was measured by ratio [heart weight (mg)/bodyweight (g) ± SE]. Student's t-test was used for statistical significance analysis (p ≤ 0.05). RESULTS: There were no significant differences between cholesterol- and chow-fed animals for collagen (34 ± 5AU vs. chow 34 ± 4 AU, p = 0.51) and elastin (66 ± 6 AU vs. chow 82 ± 7 AU, p = 0.11). Significant differences were evident for nicotinamide adenine dinucleotide (92 ± 7 AU vs. chow 118 ± 7 AU, p = 0.01), pyridoxine (56 ± 4 AU vs. chow 73 ± 4 AU, p = 0.01), flavins (44 ± 3 AU vs. chow 57 ± 4 AU, p = 0.01), lipofuscin (35 ± 3 AU vs. chow 46 ± 3 AU, p = 0.01) and ß-carotene (19 ± 2 AU vs. chow 25 ± 2 AU, p = 0.01). Cholesterol-fed animals had significantly heavier hearts (7 ± 0.3 ratio vs. chow 5 ± 0.1 ratio, p = 0.001). CONCLUSION: Cholesterol feeding induced cardiovascular disease as noted by cardiac hypertrophy in wild-type mice. A reduction was observed in pyridoxine, nicotinamide adenine dinucleotide, flavins, lipofuscin and ß-carotene, which are established risk factors for cardiovascular disease. We report no significant changes in structural proteins collagen and elastin, suggesting no generalized tissue restructuring, which might otherwise explain the observed pathological differences.
Asunto(s)
Bioensayo/métodos , Biomarcadores/metabolismo , Enfermedades Cardiovasculares/metabolismo , Colorantes Fluorescentes/metabolismo , Animales , Antioxidantes/metabolismo , Peso Corporal/fisiología , Colesterol/metabolismo , Fluorescencia , Masculino , Ratones , Ratones Endogámicos C57BL , Tamaño de los Órganos/fisiología , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Multi-functional laser non-invasive diagnostic systems allow the study of a number of microcirculatory parameters, including index of blood microcirculation (Im) (by laser Doppler flowmetry, LDF) and oxygen saturation (StO2) of skin tissue (by tissue reflectance oximetry, TRO). This research aimed to use such a system to investigate the synchronization of microvascular blood flow and oxygen saturation rhythms under normal and adaptive change conditions. Studies were conducted on eight healthy volunteers of 21-49 years. These volunteers were observed between one and six months, totalling 422 basic tests (3 min each). Measurements were performed on the palmar surface of the right middle finger and the lower forearm's medial surface. Rhythmic oscillations of LDF and TRO were studied using wavelet analysis. Combined tissue oxygen consumption data for all volunteers during 'adaptive changes' increased relative to normal conditions with and without arteriovenous anastomoses. Data analysis revealed resonance and synchronized rhythms in microvascular blood flow and oxygen saturation as an adaptive change in myogenic oscillation (vasomotion) resulting from exercise and possibly psychoemotional stress. Synchronization of myogenic rhythms during adaptive changes may lead to increased oxygen consumption as a result of increased microvascular blood flow velocity.
Asunto(s)
Adaptación Fisiológica , Microcirculación/fisiología , Oxígeno/metabolismo , Piel/irrigación sanguínea , Adulto , Anastomosis Arteriovenosa/fisiología , Respiración de la Célula , Femenino , Humanos , Flujometría por Láser-Doppler , Masculino , Persona de Mediana Edad , Oximetría , Consumo de Oxígeno/fisiología , Perfusión , Flujo Sanguíneo Regional , Adulto JovenRESUMEN
Photodynamic therapy (PDT) is a technique developed to treat the ever-increasing global incidence of cancer. This technique utilises singlet oxygen ((1)O2) generation via a laser excited photosensitiser (PS) to kill cancer cells. However, prolonged sensitivity to intensive light (6-8 weeks for lung cancer), relatively low tissue penetration by activating light (630â nm up to 4â mm), and the cost of PS administration can limit progressive PDT applications. The development of quantum-dot laser diodes emitting in the highest absorption region (1268â nm) of triplet oxygen ((3)O2) presents the possibility of inducing apoptosis in tumour cells through direct (3)O2 â (1)O2 transition. Here we demonstrate that a single laser pulse triggers dose-dependent (1)O2 generation in both normal keratinocytes and tumour cells and show that tumour cells yield the highest (1)O2 far beyond the initial laser pulse exposure. Our modelling and experimental results support the development of direct infrared (IR) laser-induced tumour treatment as a promising approach in tumour PDT.