Losartan Ameliorates Coronary Neointimal Thickening in a Mouse Model of Kawasaki Disease: A Pilot Study

Figure 1. Anti-inflammatory effects of losartan on LCWE-induced coronary arteritis. (A) Representative hematoxylin and eosin (H&E)-stained cross sections of the aortic root, including bilateral coronary arteries from phosphate-buffered saline (PBS)-injected mice (left), Lactobacillus casei cell wall extract (LCWE)-injected mice (middle), and LCWE-injected mice treated with angiotensin receptor blocker (ARB) (right). Bar graphs show the incidence of coronary arteritis (B) and aortitis (D), as well as the inflammatory scores of the coronary arteries (C) and aortas (E), in PBS-, LCWE-, and LCWE+ARB-treated mice. Scale bars: 500 μm in the upper panels and 100 μm in the lower panels. Continuous variables are presented as medians and interquartile ranges (IQRs) in each group (PBS: n = 5; LCWE: n = 6; LCWE + ARB: n = 6). Comparisons among groups were performed using Fisher’s exact test for the incidence of coronary arteritis (B) and aortitis (D) and the Kruskal–Wallis test followed by Dunn’s multiple comparisons test for the coronary artery inflammatory score (C) and aortic inflammatory score (E). * p < 0.05 and ** p < 0.01. PBS, phosphate-buffered saline; LCWE, Lactobacillus casei cell wall…

Figure 2. Immunohistochemistry of coronary artery stenosis. (A) Representative immunohistochemical staining for α-smooth muscle actin (α-SMA), calponin, and proliferating cell nuclear antigen (PCNA) in coronary artery cross-sections from phosphate-buffered saline (PBS)-injected mice (left), Lactobacillus casei cell wall extract (LCWE)-injected mice (middle), and LCWE-injected mice treated with angiotensin receptor blocker (ARB) (right). Corresponding isotype control sections are shown in the far-right panels. Scale bars: 100 μm in the low-magnification (L) panels and 50 μm in the high-magnification (H) panels. Thick dotted lines indicate the internal elastic lamina (IEL), whereas fine dotted lines indicate the external elastic lamina (EEL). Incidence of neointima (B), intimal thickness (C), coronary artery luminal stenosis rate (D), number of α-SMA-positive cells (E), number of calponin-positive cells in media (F), and number of PCNA-positive cells in intima (G) were compared among the three groups. Data are presented as the medians and interquartile ranges (IQRs) in each group (PBS: n = 5; LCWE: n = 6; LCWE+ARB: n = 6). Comparisons among groups were performed using Fisher’s exact test for…

Figure 3. Effect of losartan on LCWE-induced elastin degradation. (A) Representative Elastica van Gieson (EVG)-stained cardiac tissue sections from mice treated with phosphate-buffered saline (PBS), Lactobacillus casei cell wall extract (LCWE), or LCWE-treated mice receiving an angiotensin receptor blocker (ARB). Enlarged views of the boxed regions are shown in the middle panels. Arrowheads indicate sites of elastic fiber fragmentation in LCWE-injected mice. The lower panels show high-magnification images of matrix metalloproteinase-9 (MMP-9) staining. In LCWE-treated mice, increased MMP-9 expression (brown staining) was observed in regions corresponding to sites of elastic fiber fragmentation. Quantification of elastin breaks in the internal elastic lamina (IEL) (B) and external elastic lamina (EEL) (C) in each group (PBS: n = 5; LCWE: n = 6; LCWE+ARB: n = 6). Scale bars: 100 μm (upper panels) and 20 μm (middle and lower panels). Data are presented as medians and interquartile ranges (IQRs). Comparisons among groups were performed using the Kruskal–Wallis test followed by Dunn’s multiple comparisons test for the IEL elastin break score (B) and EEL elastin break score (C). * p < 0.001.…

Figure 4. Serum concentrations of MMP-9 (A), TIMP-1 (B), PDGF-AA (C), and TGF-β1 (D). Data are presented as medians and interquartile ranges (IQRs) (PBS: n = 5; LCWE: n = 6; LCWE+ARB: n = 6). Comparisons among groups were performed using the Kruskal–Wallis test followed by Dunn’s multiple comparisons test. * p = 0.029. MMP-9, matrix metalloproteinase-9; TIMP-1, tissue inhibitor of metalloproteinase-1; PDGF-AA, platelet-derived growth factor-AA; TGF-β1, transforming growth factor-β1.