Remodeling Matrix Synthesis in a Rat Model of Aortocaval Fistula and the Cyclic Stretch: Impaction in Pulmonary Arterial Hypertension-Congenital Heart Disease

Figures

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  Figure 1. Collagen and elastin fiber distribution in the PAs of non-PH, PAH-CHD and IPAH patients. (a) Representative the Masson’s trichrome collagen staining in the pulmonary arteries PAs from the non-PH, PAH-CHD and IPAH patientpatients. The collagen content in the PA tissue from a PAH-CHD patient was significantly increased in the medial and adventitial layers compared with that in tissues from IPAH and non-PH patients. (b) Representative modified Verhoeff elastin-stained PAs in these three groups. Internal and external elastic laminae (black staining) are apparent in the non-PAH PA patient, but loss of elastin and fragmentation (arrows) are observed in the PAH-CHD patient (Scale bar: 100 µm).

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  Figure 2. The SMC markers and ECM gene expression profiles of SMC. Representative qRT-PCR analysis. (a) The mRNA expression levels of SMC marker gene profiles. (b) ECM gene expression profiles. The expression differences were compared with GAPDH as a loading control. The SMCs were harvested for RNA at passage 1. Data are shown as the mean ± SEM in the same group of four individual SMCs isolated from either TASMCs or PASMCs. The black bars represent the TASMCs. The gray bars represent the PASMCs. * p < 0.05, ** p < 0.01, *** p < 0.001 compared with the TASMCs.

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  Figure 3. The gene profile of the TASMC and PASMC response to cyclic mechanical stretch. (a) A schematic description of the InVitro cyclic stretch model to mimic the experimental model of volume overload. Representative qRT-PCR analysis. The mRNA expression levels of (b) SMC markers or (c) the ECM gene profile from either TASMCs or PASMCs under 0% or 10% cyclic mechanical stretch. The expression differences were compared with GAPDH as a loading control. Data are shown as the mean ± SEM in the same group of four individual cell lines. The bars represent the means ± SEMs of four samples in each group. * p < 0.05, **p < 0.01 and *** p < 0.001 compared with the unstrained group.

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  Figure 4. Characterization of the ACF animal model: ACF impacts right heart hypertrophy and collagen accumulation, leading to PA fibrosis. (a) A schematic description of the creation of ACF in rats, an experimental model of volume-overload CHF. (b) Oxygenation index of the IVC in the sham, ACF and MCT-PAH groups. (c) The ratio of RV to LV plus septum weight (RV/LV+S) is shown. Means ± SEMs, *** p < 0.001 versus sham. (d) Representative Masson’s trichrome collagen staining in the PAs from the sham, ACF and MCT-PAH rat models. The PA tissue from an ACF model had significantly increased collagen accumulation in the adventitial layers compared with that in the sham and MCT-PAH models.

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  Figure 5. Effect of dynamic stretch on collagen IA2 to A1 isoform and Notch3 activation in ACF animal model. After 4 months of ACF, we then closed the aortocaval fistula for one month (ACFR). (a) Western blot showing collagen IA2 to A1 expression in total lung cell lysis. The relative expression level of each protein was quantified by densitometry and normalized to the expression level of GAPDH. (b) Western blot showing Notch1, 2, and 3 expression in total lung cell lysates. The relative expression level of each protein was quantified by densitometry and normalized to that of GAPDH. Each value represents the mean ± SE of 4 independent experiments. * p < 0.05, ** p < 0.01 and *** p < 0.001 versus sham group, one-way ANOVA, Dunnett’s post test.