Vitamin-D Deficiency and Supplementation Altered the Network of the Coronary Arteries in a Rodent Model—In Situ Video Microscopic Technique

Figure 1. Representative video-microscopic images of segmental and branching analysis (A,B) and mapping of the LAD networks in a coordinate system, following 50 μm-ring-unit analysis (C,D). Note the difference between the two experimental groups in the network density of the LAD coronary artery, shown in the image and the associated coordinate system of a typical vitamin-D-deficient (A,C) and a typical vitamin-D-supplemented animal (B,D).

Figure 2. Segments analysis. (A) Lumen area of the segments from the VD− and VD+ animals. The lumen area of the first-order branches was significantly larger in VD+ group. (B) Flow lengths of the segments from the VD− and VD+ animals. The 1st- and 4th-order branches were lengthier in VD− rats. Values are means ± SEM. Two-tailed unpaired Student’s t-test and Mann–Whitney-test. * p < 0.05 VD− vs. VD+.

Figure 3. Analysis of branching. (A) Asymmetry range of daughter branches (ratio of outer diameters). The asymmetry index (with increasing branching angle) was significantly elevated only in VD+ groups (with Pearson correlation, p < 0.05). (B) The Murray law. Branches are obeying the Murray law.

Figure 4. Analysis of ring units. (A) Number of 50 µm ring units as a function of different diameter ranges. In VD− networks, the number of rings decreased in the range of 100–300 µm (except at 250 µm), and the number of rings increased in the range of 400–550 µm. Normalized in 8/8 rats. Significantly different with the Chi-probe (p < 0.05). (B) Wall thickness of 50 µm ring units as a function of different diameter ranges. Wall thickness was increased in the 50, 350, 500, 550 and 650 µm range in VD− group. However, the wall thickness was bigger in the 200, 250, 300, 450 and 600 µm range in VD+ group. Values are means ± SEM. Mann–Whitney-test. * p < 0.05 VD− vs. VD+.

Figure 5. Frequency of ring units (color-coded) for different diameters and flow distances from the orifice. Note that in VD− rats a new population of 250 µm units appears at a 6–9 mm flow distance from the orifice, while at the same locations there is a diminishment of 350 µm units. In VD− rats, 150–200 and 300 µm units are almost missing at 10–15 mm flow distances.