Contribución a la comprensión de la microcirculación periférica y a su regulación a través de los componentes oscilatórios de flujo medido por láser Doppler

• Autores: Henrique Nuno Nazaré e Silva
• Directores de la Tesis: María Julia Araceli Buján Varela (dir. tes.), Luis Monteiro Rodrigues (codir. tes.)
• Lectura: En la Universidad de Alcalá ( España ) en 2016
• Idioma: español
• Tribunal Calificador de la Tesis: Melchor Álvarez de Mon Soto (presid.), Natalio García Honduvilla (secret.), Miguel Ángel Santos-Ruiz Díaz (voc.), Ana Catarina Beco Pinto Reis (voc.)
• Materias:
  • Ciencias médicas
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• Resumen

  • The skin is a recognized model to study normal and abnormal microcirculation, and the progressive development of non-invasive technologies, such as the laser Doppler flowmetry (LDF) and transcutaneous (tc) gasimetry reinforced that view. However, these technologies record oscillatory phenomena, complex in nature and difficult to interpret, which limits the in vivo utility of this information. The present study was designed to deepen our knowledge on these matters through the question how do LDF oscillatory components contribute to the regulation of microcirculatory function?. To answer this question the following objectives were established: (I) to develop methodologies that will allow to obtain functional microcirculatory parameters in vivo in healthy patients of different ages, and to characterize eventual changes related to ageing; (II) to find the best calculation tools to refine the LDF signal analysis; (III) to develop an animal model that allows us to test the best instruments developed, looking deeper, if possible, to the related phenomena; For the first objective two groups of healthy volunteers were studied ¿ one group of 35 healthy volunteers (22.1 ± 3.7 y.o.), and one other group of 30 volunteers, also healthy but older (50.8 ± 7.6 y.o.). In both groups the LDF signal was recorded following the application of three experimental protocols - passive leg raising (PLR), suprasystolic occlusion at the ankle level (SAO), and 100% oxygen breathing (OB). For the second objective three analytical tools were applied - the wavelet transform (WT), the detrended fluctuation analysis (DFA), and the multiscale entropy analysis (MSE). For the third objective, one group of 16 C57BL/6 mice was used (mean age 17 weeks old), submitted to a 100% oxygen breathing while anesthetized, and another group of 9 mice, 16 weeks old, submitted to an unilateral hindlimb ischemia, breathing 100% oxygen before and after procedure.