The expression of survivin in irreversible pulmonary arterial hypertension rats and its value in evaluating the reversibility of pulmonary arterial hypertension secondary to congenital heart disease

Figures

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  Fig. 1.. Time schema of animal study. Rats in the control (n = 10) and reversible PAH groups (n = 10) received subcutaneous injection of 0.2 mL DMSO or monocrotaline at 40 mg/kg in 0.2 mL DMSO one week after thoracotomy, respectively. The irreversible PAH rats (n = 10) underwent monocrotaline injection at 40 mg/kg in 0.2 mL DMSO one week after left pneumonectomy. The hemodynamics measurements and tissue harvest were performed three weeks after the beginning of the experiment in the control group and reversible PAH group, and at five weeks in the irreversible PAH group.

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  Fig. 2.. Increased mPAP and decreased cardiac index in irreversible PAH rats. (a) The systemic arterial pressure measured by catheterizing into the femoral artery were similar among the three groups. (b) The mPAP measured through a pulmonary arterial catheter was increased in rats from both the reversible PAH and irreversible PAH groups when compared to the control group. (c) The right ventricular hypertrophy index indicated by the ratio of RV/(LV+S) were significantly increased in the irreversible PAH group, but changed insignificantly in the reversible PAH group. (d) Cardiac index measured using Fick equation was significantly lower in the irreversible PAH group than in both the control and reversible PAH groups. The differences among the three groups (n = 10 in each group) were analyzed by one-way ANOVA followed by Bonferroni post hoc test. SBP, systemic blood pressure; mPAP, mean pulmonary arterial pressure; RV/(LV+S), right ventricle weight/(left ventricle + septum weight); CI, cardiac index. *P < 0.05 vs. control group, #P < 0.05 vs. reversible PAH group.

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  Fig. 3.. Neointimal formation resulted in vascular obstructive lesions in small pulmonary arteries from irreversible PAH group rats. (a) Normal small pulmonary arteries without occlusion stained by elastic Van Gieson stain in the control group. (b) Medial hypertrophy with mild occlusion (<50%) in the reversible PAH group. (c) Neointimal formation with prominent occlusion (>50%) in the irreversible PAH group. (d) Significant vascular occlusive lesions assessed by vascular occlusion score developed in small pulmonary arteries from irreversible PAH rats (P < 0.05 vs. control group), while the occlusion was mild in the reversible PAH group with an insignificant difference with that in the control group. (e) The neointimal formation developed in most of investigated small pulmonary arteries from the irreversible PAH group, while only a very small amount of investigated small pulmonary arteries from the reversible PAH group developed neointimal formation. VOS, vascular obstruction score. #P < 0.05 vs. reversible PAH group.

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  Fig. 4.. Decreased apoptosis associated with increased survivin expression in irreversible PAH rats. (a–c) TUNEL staining in the control group, reversible PAH group, and irreversible PAH group. (d) Apoptosis measured by TUNEL-positive cells increased significantly in the reversible PAH group (P < 0.05 vs. control group) while decreased significantly in the irreversible PAH group. (e–g) Survivin expression measured by immunohistochemical staining in the control group, reversible PAH group, and irreversible PAH group. (h) Survivin expression evaluated by survivin-positive cells was significantly increased in the irreversible PAH group when compared to both the control group and reversible PAH group. The differences among the three groups (n = 10 in each group) were analyzed by one-way ANOVA followed by Bonferroni post hoc test. *P < 0.05 vs. control group, #P < 0.05 vs. reversible PAH group.

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  Fig. 5.. Increased serum level of survivin and overexpression of survivin in lung from irreversible PAH rats. (a) Serum level of survivin from peripheral vein in the irreversible PAH group was significantly higher than that in both control and reversible PAH rats. (b) Representative immunoblots and densitometry demonstrating increased protein expression of survivin in lung from irreversible PAH rats. The differences among the three groups (n = 10 in each group) were analyzed by one-way ANOVA followed by Bonferroni post hoc test. *P < 0.05 vs. control group, #P < 0.05 vs. reversible PAH group.

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  Fig. 6.. Increased serum survivin level in patients with residue PAH. (a) The level of survivin in patients with irreversible PAH (n = 22) was significantly higher than that in both control (n = 10) and reversible PAH group patients (n = 38). The differences among the three groups (n = 10 in each group) were analyzed by one-way ANOVA followed by Bonferroni post hoc test. (b) The patients in the irreversible PAH group (n = 22) had increased postoperative mPAP than that in the reversible PAH group (n = 38). The difference between the two groups was tested with independent samples t-test. (c) The level of BNP in patients with irreversible PAH (n = 22) was significantly higher than that in both control (n = 10) and reversible PAH group patients (n = 38). The serum BNP in the reversible PAH group was significantly higher than that in the control group. The differences among the three groups (n = 10 in each group) were analyzed by one-way ANOVA followed by Bonferroni post hoc test. *P < 0.05 vs. control group, #P < 0.05 vs. reversible PAH group. Po-mPAP, postoperative mean pulmonary arterial pressure; BNP, brain natriuretic peptide.

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  Fig. 7.. Correlations of serum survivin with pulmonary hemodynamics and ROC curve for serum survivin. The serum survivin level was found to be correlated to the level of preoperative PVRi (a), postoperative mPAP (b), and ΔmPAP (c); negative correlation of serum survivin with mPAP (d), mPAP/MAP (e), and Qp/Qs (f). The correlations between the concentration of survivin and pulmonary hemodynamics were evaluated with Pearson's correlation coefficient, respectively. (g) ROC analysis for predicting the reversibility of PAH after shunt closure in patient with PAH secondary to CHD. (h) A positive correlation of serum survivin with BNP was observed. PVRi, pulmonary vascular resistance index; mPAP, mean pulmonary arterial pressure; ΔmPAP, the difference of mPAP between before surgery and after surgery; MAP, mean arterial pressure; Qp/Qs, pulmonary-to-systemic blood flow ratio; BNP, brain natriuretic peptide.