Background Preventing pulmonary vascular remodeling is a key strategy for pulmonary hypertension (PH). Causes of PH include pulmonary vasoconstriction and inflammation. This study aimed to determine whether cilostazol (CLZ), a phosphodiesterase-3 inhibitor, prevents monocrotaline (MCT)- and chronic hypoxia (CH)-induced PH development in rats. Methods Fifty-one male Sprague–Dawley rats were fed rat chow with (0.3% CLZ) or without CLZ for 21 days after a single injection of MCT (60 mg/kg) or saline. Forty-eight rats were fed rat chow with and without CLZ for 14 days under ambient or hypobaric (air at 380 mmHg) CH exposure. The mean pulmonary artery pressure (mPAP), the right ventricle weight-to-left ventricle + septum weight ratio (RV/LV + S), percentages of muscularized peripheral pulmonary arteries (%Muscularization) and medial wall thickness of small muscular arteries (%MWT) were assessed. Levels of the endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (peNOS), AKT, pAKT and IκB proteins in lung tissue were measured using Western blotting. Monocyte chemotactic protein (MCP)-1 mRNA in lung tissue was also assessed. Results mPAP [35.1 ± 1.7 mmHg (MCT) (n = 9) vs. 16.6 ± 0.7 (control) (n = 9) (P < 0.05); 29.1 ± 1.5 mmHg (CH) (n = 10) vs. 17.5 ± 0.5 (control) (n = 10) (P < 0.05)], RV/LV + S [0.40 ± 0.01 (MCT) (n = 18) vs. 0.24 ± 0.01 (control) (n = 10) (P < 0.05); 0.41 ± 0.03 (CH) (n = 13) vs. 0.27 ± 0.06 (control) (n = 10) (P < 0.05)], and %Muscularization and %MWT were increased by MCT injection and CH exposure. CLZ significantly attenuated these changes in the MCT model [mPAP 25.1 ± 1.1 mmHg (n = 11) (P < 0.05), RV/LV + S 0.30 ± 0.01 (n = 14) (P < 0.05)]. In contrast, these CLZ effects were not observed in the CH model. Lung eNOS protein expression was unchanged in the MCT model and increased in the CH model. Lung protein expression of AKT, phosphorylated AKT, and IκB was downregulated by MCT, which was attenuated by CLZ; the CH model did not change these proteins. Lung MCP-1 mRNA levels were increased in MCT rats but not CH rats. Conclusions We found model differences in the effect of CLZ on PH development. CLZ might exert a preventive effect on PH development in an inflammatory PH model but not in a vascular structural change model of PH preceded by vasoconstriction. Thus, the preventive effect of CLZ on PH development might depend on the PH etiology.

Background: A combination of dexmedetomidine and propofol is considered advantageous for maintaining spontaneous breathing with a satisfactory depth of anesthesia. However, the incidence of upper airway obstruction under sedation with dexmedetomidine and propofol in patients with Fontan circulation remains unanswered. This study aimed to evaluate upper airway patency and oxygen desaturation during sedation with dexmedetomidine and propofol for cardiac catheterization in pediatric patients with Fontan circulation. Methods: In this descriptive study, we reviewed medical records of patients with Fontan circulation who underwent cardiac catheterization between December 2018 and August 2020 at a single-center 200-bed academic children's hospital in Japan. Results: A total of 35 patients with Fontan circulation sedated with a departmental protocol of dexmedetomidine and propofol infusion for cardiac catheterization were reviewed. Overall, the incidence of airway interventions and oxygen desaturation were 31.4% and 28.6%, respectively. In children with a history of snoring and additional use of intravenous midazolam, the rates of airway interventions were 50% and 100%, respectively. In patients ≤2 years old with recent upper respiratory infection (URI) symptoms, oxygen desaturation rate was 75%. Conclusions: In children with Fontan circulation, the incidence rate of upper airway obstruction was high under sedation with dexmedetomidine and propofol during cardiac catheterization, which is commonly considered safe in children without Fontan circulation. A history of snoring, an additional bolus of IV midazolam, and the presence of recent URI symptoms in patients ≤2 years old are potential risks for upper airway obstruction.

Background: Preventing pulmonary vascular remodeling is a key strategy for pulmonary hypertension (PH). Causes of PH include pulmonary vasoconstriction and inflammation. This study aimed to determine whether cilostazol (CLZ), a phosphodiesterase-3 inhibitor, prevents monocrotaline (MCT)- and chronic hypoxia (CH)-induced PH development in rats.Methods: Fifty-one male Sprague-Dawley rats were fed rat chow with (0.3% CLZ) or without CLZ for 21 days after a single injection of MCT (60 mg/kg) or saline. Forty-eight rats were fed rat chow with and without CLZ for 14 days under ambient or hypobaric (air at 380 mmHg) CH exposure. Mean PAP (mPAP), the right ventricle weight-to-left ventricle+septum weight ratio (RV/LV+S), percentages of muscularized peripheral pulmonary arteries (%Muscularization) and medial wall thickness of small muscular arteries (%MWT) were assessed.Protein expression of endothelial nitric oxide synthase (eNOS), phosphorylated eNOS (peNOS), AKT, pAKT and IκB in lung tissue was measured by Western blotting. Monocyte chemotactic protein (MCP)-1 mRNA in lung tissue was also assessed.Results: mPAP [35.1±1.7 mmHg (MCT) (n=9) vs.16.6±0.7 (control) (n=9) (p<0.05); 29.1±1.5 mmHg (CH) (n=10) vs. 17.5±0.5 (control) (n=10) (p<0.05)], RV/LV+S [0.40±0.01 (MCT) (n=18) vs. 0.24±0.01 (control) (n=10) (p<0.05); 0.41±0.03 (CH) (n=13) vs. 0.27±0.06 (control) (n=10) (p<0.05)], and %Muscularization and %MWT were increased by MCT injection and CH exposure. CLZ significantly attenuated these changes in the MCT model [mPAP 25.1±1.1 mmHg (n=11) (p<0.05), RV/LV+S 0.30±0.01 (n=14) (p<0.05)]. In contrast, these CLZ effects were not observed in the CH model. Lung eNOS protein expression was unchanged in the MCT model and high in the CH model. Lung protein expression of AKT, phosphorylated AKT, and IκB was downregulated by MCT, which was attenuated by CLZ; the CH model did not change these proteins. Lung MCP-1 mRNA levels were increased in MCT rats but not CH rats.Conclusion: We found model differences in the effect of CLZ on PH development. CLZ might have a preventable effect on PH development in an inflammatory PH model but not in a vascular structural change model of PH preceded by vasoconstriction. Thus, the preventive effect of CLZ on PH development might be dependent on PH etiology.

No abstract