Three-dimensional quantitative evaluation of hypertension-induced aortic fibre remodelling based on multiphoton microscopy: a cross-age perspective

Hypertension is the primary cause of cardiovascular diseases, and its worldwide prevalence has continued to increase recently. Aortic fibre remodelling is critical in the development of hypertension and is strikingly age-related. However, the underlying microlevel variations remain unknown. This study quantitatively evaluated the hypertension-induced microstructural remodelling of aortic fibres from a cross-age perspective by combining label-free multiphoton microscopy (MPM) imaging with a three-dimensional (3D) grey-level co-occurrence matrix (GLCM) algorithm. First, MPM imaging of aortic collagen and elastin fibres was performed on spontaneously hypertensive rats and Wistar-Kyoto controls across three critical age stages (prehypertension, developing hypertension and stable hypertension) and two aortic segments (abdominal aorta and thoracic aorta). Subsequently, the 3D GLCM texture features that were significantly correlated with hypertension or age-related hypertension were identified. By deciphering these features, we revealed quantitative details of hypertension-induced aortic remodelling, hypertension-accelerated aortic ageing and the heterogeneous response of different aortic segments to hypertension from the perspective of the fibre microstructure. The proposed method and derived findings may shed new light on the mechanism of age-related hypertension and contribute significantly to the research on cardiovascular diseases.