Study of the Effect of Treatment With Atrial Natriuretic Peptide (ANP) and Cinaciguat in Chronic Hypoxic Neonatal Lambs on Residual Strain and Microstructure of the Arteries

Figures

• 

  FIGURE 1. (A) Scheme of the arteries studied in this work. (B) Representative image of an arterial segment.

• 

  FIGURE 2. (A) Axial pre-stretch test scheme. (B) Ring opening test scheme.

• 

  FIGURE 3. Scheme of four characteristic zones where micrographs were collected, each at a 90° angle to the other.

• 

  FIGURE 4. Counting protocol: (A) Histology image sample. (B) ROI selection within media layer. (C) Color thresholding. (D) Particle analyzer result.

• 

  FIGURE 5. Axial pre-stretch results. (A) Global axial pre-stretch of the aorta (number of samples: Control = 3, ANP = 5, Cinaciguat = 4). (B) Average axial pre-stretch of the aorta, segmented 5 times from the ascending thoracic aorta to the distal abdominal aorta. (C) Global axial pre-stretch of carotid artery (number of samples: Control = 3, ANP = 5, Cinaciguat = 4). (D) Average axial pre-stretch of the carotid, segmented 7 times from the proximal (PCA) to the distal zone (DCA). (E) Global axial pre-stretch of the femoral artery (number of samples: Control = 2, ANP = 4, Cinaciguat = 4). (F) Average axial pre-stretch of the femoral arteries, segmented 6 times from the proximal to the distal zone. Groups are Control (black), ANP (white) and Cinaciguat (gray). Values are expressed as mean ± SEM. Significant differences (p ≤ 0.05, t-student) between groups are represented in square brackets.

• 

  FIGURE 6. Ring-opening test results. (A) Opening angle of aorta, according to its group and sector, where ATA, Ascending thoracic Aorta (number of samples: Control = 6, ANP = 6, Cinaciguat = 6); PAA, Proximal abdominal Aorta (number of samples: Control = 6, ANP = 5, Cinaciguat = 6); DAA, Distal abdominal Aorta (number of samples: Control = 6, ANP = 6, Cinaciguat = 6). (B) Opening angle of the carotid arteries, according to their group and sector (number of samples in PCA and DCA: Control = 6, ANP = 6, Cinaciguat = 6). (C) Opening angle in femoral arteries, with their corresponding groups (number of samples FA: Control = 4, ANP = 6, Cinaciguat = 6). Values are expressed as mean ± SEM. Significant differences (p ≤ 0.05, t-student) between groups are represented in square brackets.

• 

  FIGURE 7. (A) Different zones and layers distinguishable in an artery. Representative micrograph of the Elastic Van Gieson (B) proximal abdominal aorta (PAA), (C) proximal carotid artery (PCA) and (D) femoral artery (FA). Black line under each image is a scale bar indicating a reference of 200 μm. From histological results it is possible to get information about the geometrical measurements of each artery layer and the arterial composition. Table 3 shows tunica media thickness (denoted as media) and the sum of tunica externa and tunica adventitia thickness (denoted as adventitia) (Witter et al., 2017), ratio between area luminal and vascular, and percentage content of elastin and collagen in cross section of aorta, carotid and femoral arteries. The content of elastic fibers was made inside the media layer.

• 

  FIGURE 8. Correlation analysis between biomechanical and histological results. (A) elastin vs. opening angle. (B) Collagen vs. opening angle. Groups are Control (black), ANP (white) and Cinaciguat (gray).