Tenascin-C in Tissue Repair after Myocardial Infarction in Humans

Figure 1. Histology and immunostaining of serial section border zone myocardium at inflammatory phase (case 15). The coagulative necrotic cardiomyocytes with eosinophilic cytoplasm and no nuclei and neutrophil infiltration are seen (in enlarged area). Scale bar = 100 μm.

Figure 2. (A) Histology and immunostaining of serial sections of myocardial lesion at the early granulation phase, five days after the onset (case 6). CD31-positive angiogenic sprouting and CD68-positive macrophage infiltration are noted in the TNC-positive area at the border zone. Arrowheads indicate αSMA-positive blood vessels, but very few αSMA-positive fibroblasts are seen. Scale bar = 100 μm. (B) Collagen fibers observed under the polarizing microscope of the elastica Sirius red-stained myocardial section. With the use of band-pass filters, the red fibers are composed mainly of collagen type I, and the green fibers are composed mainly of collagen type III. A few thin collagen fibers are seen in the granulation tissue. Scale bar = 100 μm.

Figure 3. (A) Histology and immunostaining of serial sections of myocardial lesions at the fibrogenic phase, ten days after the onset (case 2). Arrows indicate lymphatic vessels in the TNC-negative area. Numerous CD31-positive blood vessels and αSMA-positive myofibroblasts are seen. Scale bar = 100 μm. (B) Collagen fibers observed under the polarizing microscope of the elastica Sirius red-stained myocardial section. Randomly arranged thin and short collagen fibers are seen in the infarct area. Scale bar = 100 μm.

Figure 4. (A) Histology and immunostaining of serial sections of myocardial lesion at the scar phase (case 19). No TNC staining is seen at this stage. Macrophages (CD68 positive), myofibroblasts (αSMA positive), blood vessels (CD31 positive), and lymphatic vessels (podoplanin positive) are significantly reduced. Scale bar = 200 μm. (B) Collagen fibers observed under the polarizing microscope of elastica sirius red-stained myocardial sections. Well-organized thick collagen fibers are seen in the scar tissue. Scale bar = 100 μm.

Figure 5. (A) Representative photos of blood and lymphatic vessels in each phase. (a–c) Intact area: Numerous CD31-positive capillary vessels are observed around cardiomyocytes, while fewer podoplanin-positive lymphatic vessels are present. (d–f) Inflammatory phase: Cardiomyocytes show coagulative necrosis. Neutrophils infiltrate an edematous interstitium. Blood vessels and lymphatic vessels disappear. (g–i) Granulation phase: New CD31-positive capillary vessels proliferate. A few podoplanin-positive cells are observed. (j–l) Fibrogenic phase: The number of lymphatic vessels increases, while that of blood vessels decreases. (m–o) Scar phase: The only remaining tissue is a fibrotic scar, which does not contain any cellular components. Blood vessels and lymphatic vessels are no longer present. Scale bar = 200 μm. (B) Densities of blood vessels and lymphatic vessels in each phase. (i) Blood vessels: Blood vessels decrease in the inflammatory phase and peak in number in the granulation phase. They then gradually decrease during the fibrogenic and scar phases. (ii) Lymphatic vessels: Lymphatic vessels are rarely present in intact areas. They disappear in the inflammatory phase, gradually…

Figure 6. RNA-seq analysis of TNC-modulated genes. (A) Scatter plot displaying differentially expressed genes (DEGs) from the RNA-seq analysis of control and TNC-treated LECs. Up- and down-regulated genes are represented in red and blue, respectively. Values are shown as the log2 of normalized counts. (B) RNA-seq comparison identifying seven positively regulated genes (red) and four negatively regulated genes (blue). (C) Heatmap illustrating the expression profiles of positively and negatively regulated genes following the TNC treatment. The red bar represents Up-regulated, and the blue bar represents Down-regulated gene groups. The darker magenta color indicates higher gene expression and the darker cyan color indicates lower expression. (D) DEGs categorized based on their gene ontology (GO) annotation in biological processes, using the generally applicable gene-set enrichment (GAGE) method.