Impaired Relaxation in Induced Pluripotent Stem Cell-Derived Cardiomyocytes with Pathogenic TNNI3 Mutation of Pediatric Restrictive Cardiomyopathy.

BACKGROUND: Restrictive cardiomyopathy (RCM) is characterized by impaired diastolic function with preserved ventricular contraction. Several pathogenic variants in sarcomere genes, including TNNI3, are reported to cause Ca2+ hypersensitivity in cardiomyocytes in overexpression models; however, the pathophysiology of induced pluripotent stem cell (iPSC)-derived cardiomyocytes specific to a patient with RCM remains unknown. METHODS AND RESULTS: We established an iPSC line from a pediatric patient with RCM and a heterozygous TNNI3 missense variant, c.508C>T (p.Arg170Trp; R170W). We conducted genome editing via CRISPR/Cas9 technology to establish an isogenic correction line harboring wild type TNNI3 as well as a homozygous TNNI3-R170W. iPSCs were then differentiated to cardiomyocytes to compare their cellular physiological, structural, and transcriptomic features. Cardiomyocytes differentiated from heterozygous and homozygous TNNI3-R170W iPSC lines demonstrated impaired diastolic function in cell motion analyses as compared with that in cardiomyocytes derived from isogenic-corrected iPSCs and 3 independent healthy iPSC lines. The intracellular Ca2+ oscillation and immunocytochemistry of troponin I were not significantly affected in RCM-cardiomyocytes with either heterozygous or homozygous TNNI3-R170W. Electron microscopy showed that the myofibril and mitochondrial structures appeared to be unaffected. RNA sequencing revealed that pathways associated with cardiac muscle development and contraction, extracellular matrix-receptor interaction, and transforming growth factor-ß were altered in RCM-iPSC-derived cardiomyocytes. CONCLUSIONS: Patient-specific iPSC-derived cardiomyocytes could effectively represent the diastolic dysfunction of RCM. Myofibril structures including troponin I remained unaffected in the monolayer culture system, although gene expression profiles associated with cardiac muscle functions were altered.

Long-term safety and tolerability of ambrisentan treatment for pediatric patients with pulmonary arterial hypertension: An open-label extension study.

This open-label, extension study assessed long-term safety, tolerability, and efficacy of ambrisentan in a pediatric population (age 8- < 18 years) with pulmonary arterial hypertension (PAH). Following completion of a 6-month, randomized study, participants entered the long-term extension at individualized ambrisentan dosages (2.5/5/7.5 or 10 mg/day). Safety assessments included adverse events (AEs), AEs of special interest, and serious AEs (SAEs); efficacy outcomes included 6-min walking distance (6MWD) and World Health Organization functional class (WHO FC). Thirty-eight of 41 (93%) randomized study participants entered the extension; 21 (55%) completed (reaching age 18 years). Most participants received concomitant phosphodiesterase-5 inhibitors (n = 25/38, 66%). Median ambrisentan exposure was 3.5 years. Most participants experienced ≥ 1 AE (n = 34/38, 89%), and 21 (55%) experienced SAEs, most commonly worsening PAH (n = 3/38, 8%), acute cardiac failure, pneumonia, or anemia (n = 2/38; 5% each); none considered ambrisentan-related. Seven participants (18%) died, with recorded reasons (MedDRA preferred term): cardiac failure (n = 2), PAH (n = 2), COVID-19 (n = 1), acute right ventricular failure (n = 1), and failure to thrive (n = 1); median time to death: 5.2 years. Anemia and hepatotoxicity AEs were generally mild to moderate and did not require ambrisentan dose adjustment. Assessed at study end in 29 participants (76%), mean 6MWD improved by 17% (standard deviation: 34.3%), and all (29/29, 100%) had improved or unchanged WHO FC.    Conclusion: Long-term weight-based ambrisentan dosing, alone or combined with other PAH therapies in children with PAH aged 8- < 18 years, exhibited tolerability and clinical improvements consistent with prior randomized study results.    Trial registration: NCT01342952, April 27, 2011. What is Known: • The endothelin receptor antagonist, ambrisentan, is indicated for treatment of pulmonary arterial hypertension (PAH). Previous studies have shown similar efficacy and tolerability in pediatric patients as in adults. What is New: • This open-label extension study assessed the long-term use of ambrisentan in pediatric patients (8-<18 years) with PAH, most of whom were also receiving recommended background PAH treatment. • Weight-based dosing of ambrisentan, given alone or in combination with other PAH therapies, was well tolerated with clinical improvements consistent with prior randomized study results.

Anti-α6ß4 integrin autoantibodies inhibit the binding of laminins to α6ß4 integrin in patients with pemphigoid and affect the gastrointestinal tract.

BACKGROUND: Anti-α6ß4 integrin autoantibodies can be observed in some patients with mucous membrane pemphigoid. We have previously identified anti-α6ß4 integrin extracellular domain autoantibodies together with anti-BP180 NC16A antibodies in a patient with DPP-4 inhibitor-induced bullous pemphigoid. However, the significance and impact of anti-α6ß4 integrin antibodies are unknown. OBJECTIVES: To characterize anti-α6ß4 integrin extracellular domain autoantibodies in pemphigoid patients, to determine whether these antibodies inhibit laminin-α6ß4 integrin binding and to observe their systemic effects. METHODS: Anti-α6ß4 integrin autoantibodies were analysed by staining cells expressing the extracellular region of α6ß4 integrin with sera from 20 patients with pemphigoid. The anti-α6ß4 integrin autoantibodies were characterized using different transfectants. The binding of laminins to α6ß4 integrin was studied using cells expressing the activated conformation of α6ß4 integrin and the inhibitory effect of the autoantibodies on the binding of laminins to α6ß4 integrin was tested. Trends in antibody titres and clinical symptoms were quantified and analysed. RESULTS: IgG autoantibodies against the extracellular domain of anti-α6ß4 integrin were found in some patients with pemphigoid. Laminin binding to α6ß4 integrin was observed in the active conformation of α6ß4 integrin, and serum from a patient with a high titre of anti-α6ß4 integrin antibodies inhibited the binding of both laminin-511 and laminin-332 to α6ß4 integrin. α6ß4 integrin is expressed on the basement membrane of both skin and small intestine, and exfoliation was observed in the patient's epidermis and small intestinal epithelium. A reduction in the titre of the anti-α6ß4 integrin antibody was associated with improvement in both skin and gastrointestinal symptoms. CONCLUSIONS: This study demonstrated the presence of anti-α6ß4 integrin extracellular domain-specific autoantibodies in some patients with pemphigoid. In addition, these autoantibodies showed inhibitory activity on α6ß4 integrin-laminin binding. Anti-α6ß4 integrin antibodies can affect the gastrointestinal tract as well as the skin and oral mucosa.

Isogenic pairs of induced-pluripotent stem-derived endothelial cells identify DYRK1A/PPARG/EGR1 pathway is responsible for Down syndrome-associated pulmonary hypertension.

Down syndrome (DS) is the most prevalent chromosomal disorder associated with a higher incidence of pulmonary arterial hypertension (PAH). The dysfunction of vascular endothelial cells (ECs) is known to cause pulmonary arterial remodeling in PAH, although the physiological characteristics of ECs harboring trisomy 21 (T21) are still unknown. In this study, we analyzed the human vascular ECs by utilizing the isogenic pairs of T21-induced pluripotent stem cells (iPSCs) and corrected disomy 21 (cDi21)-iPSCs. In T21-iPSC-derived ECs, apoptosis and mitochondrial reactive oxygen species (mROS) were significantly increased, and angiogenesis and oxygen consumption rate (OCR) were significantly impaired as compared with cDi21-iPSC-derived ECs. The RNA-sequencing identified that EGR1 on chromosome 5 was significantly upregulated in T21-ECs. Both EGR1 suppression by siRNA and pharmacological inhibitor could recover the apoptosis, mROS, angiogenesis, and OCR in T21-ECs. Alternately, the study also revealed that DYRK1A was responsible to increase EGR1 expression via PPARG suppression, and that chemical inhibition of DYRK1A could restore the apoptosis, mROS, angiogenesis, and OCR in T21-ECs. Finally, we demonstrated that EGR1 was significantly upregulated in the pulmonary arterial ECs from lung specimens of a patient with DS and PAH. In conclusion, DYRK1A/PPARG/EGR1 pathway could play a central role for the pulmonary EC functions and thus be associated with the pathogenesis of PAH in DS.

Quantitative estimation of phospholipid molecules desorbed from a microbubble surface under ultrasound irradiation.

Microbubbles have potential applications as drug and gene carriers, and drug release can be triggered by externally applied ultrasound irradiation while inside blood vessels. Desorption of molecules forming the microbubble shell can be observed under ultrasound irradiation of a single isolated microbubble, and the volume of desorbed molecules can be quantitatively estimated from the contact angle between the bubble and a glass plate. Microbubbles composed of a 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) shell and a poorly-soluble gas are created. When the microbubbles are exposed to a pulsed ultrasound, the contact angles increase dramatically; the percentage of DMPC molecules desorbed from the bubble surface reaches 70%. Vibration of a single bubble in the radial direction is measured using a laser Doppler vibrometer. The relationship between the vibrational characteristics and the amount of molecular desorption reveals that a larger vibrational amplitude of the bubble around the resonance size induces a larger amount of molecular desorption. These results support the possibility of controlling molecular desorption with pulsed ultrasound.

Clinical Outcomes and Genetic Analyses of Restrictive Cardiomyopathy in Children.

BACKGROUND: Restrictive cardiomyopathy in children is rare and outcomes are very poor. However, little information is available concerning genotype-outcome correlations. METHODS: We analyzed the clinical characteristics and genetic testing, including whole exome sequencing, of 28 pediatric restrictive cardiomyopathy patients who were diagnosed from 1998 to 2021 at Osaka University Hospital in Japan. RESULTS: The median age at diagnosis (interquartile range) was 6 (2.25-8.5) years. Eighteen patients received heart transplantations and 5 patients were on the waiting list. One patient died while waiting for transplantation. Pathologic or likely-pathogenic variants were identified in 14 of the 28 (50%) patients, including heterozygous TNNI3 missense variants in 8 patients. TNNT2, MYL2, and FLNC missense variants were also identified. No significant differences in clinical manifestations and hemodynamic parameters between positive and negative pathogenic variants were detected. However, 2- and 5-year survival rates were significantly lower in patients with pathogenic variants (50% and 22%) compared with survival in patients without pathogenic variants (62% and 54%; P=0.0496, log-rank test). No significant differences were detected in the ratio of patients diagnosed at nationwide school heart disease screening program between positive and negative pathogenic variants. Patients diagnosed by school screening showed better transplant-free survival compared with patients diagnosed by heart failure symptoms (P=0.0027 in log-rank test). CONCLUSIONS: In this study, 50% of pediatric restrictive cardiomyopathy patients had pathogenic or likely-pathogenic gene variants, and TNNI3 missense variants were the most frequent. Patients with pathogenic variants showed significantly lower transplant-free survival compared with patients without pathogenic variants.

Pathogenic Roles of Cardiac Fibroblasts in Pediatric Dilated Cardiomyopathy.

Background Dilated cardiomyopathy (DCM) is a major cause of heart failure in children. Despite intensive genetic analyses, pathogenic gene variants have not been identified in most patients with DCM, which suggests that cardiomyocytes are not solely responsible for DCM. Cardiac fibroblasts (CFs) are the most abundant cell type in the heart. They have several roles in maintaining cardiac function; however, the pathological role of CFs in DCM remains unknown. Methods and Results Four primary cultured CF cell lines were established from pediatric patients with DCM and compared with 3 CF lines from healthy controls. There were no significant differences in cellular proliferation, adhesion, migration, apoptosis, or myofibroblast activation between DCM CFs compared with healthy CFs. Atomic force microscopy revealed that cellular stiffness, fluidity, and viscosity were not significantly changed in DCM CFs. However, when DCM CFs were cocultured with healthy cardiomyocytes, they deteriorated the contractile and diastolic functions of cardiomyocytes. RNA sequencing revealed markedly different comprehensive gene expression profiles in DCM CFs compared with healthy CFs. Several humoral factors and the extracellular matrix were significantly upregulated or downregulated in DCM CFs. The pathway analysis revealed that extracellular matrix receptor interactions, focal adhesion signaling, Hippo signaling, and transforming growth factor-ß signaling pathways were significantly affected in DCM CFs. In contrast, single-cell RNA sequencing revealed that there was no specific subpopulation in the DCM CFs that contributed to the alterations in gene expression. Conclusions Although cellular physiological behavior was not altered in DCM CFs, they deteriorated the contractile and diastolic functions of healthy cardiomyocytes through humoral factors and direct cell-cell contact.

Use of drug-coated balloon instead of drug-eluting stent for pediatric cardiac allograft vasculopathy.

Cardiac allograft vasculopathy (CAV) sometimes leads to restenosis, even after percutaneous transcatheter intervention. Recently, drug-coated balloons (DCBs) have been successfully used to treat coronary artery disease, especially CAVs, in adults. However, no studies have used DCBs in pediatric CAVs. We encountered a patient with CAV who underwent cardiac transplantation for restrictive cardiomyopathy at the age of 2 years. Nine years after the transplantation, severe stenosis of the proximal left anterior descending branch was observed. Considering the patient's young age and the possibility of restenosis, we performed an intervention with DCB. Follow-up conducted 7 months after the intervention showed no restenosis. Cardiac coronary artery lesions following transplantation are more likely to result in restenosis earlier than arteriosclerotic lesions. In pediatric patients, restenosis might require multiple stents and prolonged antiplatelet therapy. Our findings provide evidence supporting the possibility of an effective treatment of CAV in children.

Cardiomyocyte deoxyribonucleic acid damage and cardiac recovery in paediatric dilated cardiomyopathy.

OBJECTIVES: The goal of this study was to identify the clinical significance of the deoxyribonucleic acid (DNA) damage response marker, phosphorylated H2A histone variant X, on the bridge to recovery in low-weight paediatric patients with dilated cardiomyopathy (DCM) after having a Berlin Heart EXCOR implanted. METHODS: Consecutive paediatric patients with DCM who had an EXCOR implanted for DCM at our hospital between 2013 and 2021 were reviewed. Patients were classified into 2 groups according to the degree of DNA damage in the left ventricular cardiomyocytes-the low DNA damage group and the high DNA damage group-using the median value as the threshold. We examined and compared the preoperative factors and histologic findings associated with cardiac functional recovery following the explant procedure in the 2 groups. RESULTS: Competing outcome analysis of 18 patients (median body weight, 6.1 kg) showed that the incidence of an EXCOR explant was 40% at 1 year after the implant procedure. Serial echocardiography revealed significant left ventricular functional recovery in the low DNA damage group 3 months after the implant. The univariable Cox proportional hazards model revealed that the percentage of phosphorylated H2A histone variant X-positive cardiomyocytes was the significant factor associated with cardiac recovery and the EXCOR explant (hazard ratio, 0.16; 95% confidence interval, 0.027-0.51; P = 0.0096). CONCLUSIONS: The degree of DNA damage response to the EXCOR implant may aid in predicting the bridge to recovery with EXCOR among low-weight paediatric patients with DCM.

Trans-subclavian approach for Impella CP implantation using the chimney graft in a pediatric patient with fulminant myocarditis during extracorporeal support.

Impella is a device effective for the treatment of cardiogenic shock. However, among small children, its application has limitations due to left ventricle size and vasculature and the turning diameter of the aortic arch. Herein, we report an 11-year-old girl with fulminant myocarditis who was successfully managed with Impella CP implantation via the right subclavian artery using a polyethylene terephthalate chimney graft. Compared with insertion via the femoral artery, this method has several advantages. That is, it can address limitations in aortic arch diameter and facilitate equable fixation of the Impella device in small pediatric patients.

Immunogenicity of SARS-CoV-2 vaccination in adolescents with cardiac disease.

BACKGROUND: Although widely reported to affect older adults more, coronavirus disease 2019 (COVID-19) also affects adolescents, especially those with co-morbidities, including heart diseases. The safety and efficacy of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines has been established in healthy adolescents, yet there are few data for humoral and cellular immunogenicity in adolescents with cardiac diseases. METHODS: We evaluated anti-spike antibodies, neutralizing activities, and interferon-gamma production prior to and after SARS-CoV-2 vaccination in adolescents with cardiac diseases and healthy controls. RESULTS: Five healthy adolescents and 26 patients with cardiac diseases, including congenital heart disease (CHD, n = 10), dilated cardiomyopathy (DCM, n = 4), idiopathic pulmonary arterial hypertension (IPAH, n = 4), and those post-heart transplantation (post-HTx, n = 8) were enrolled. No severe adverse events, including myocarditis and pericarditis, were noted, even in patients with severe heart failure. Febrile events were noted after 21 of 62 injections (34%). All the healthy adolescents and 21 of the 26 patients (81%) showed sufficient elevation of neutralizing antibodies after the second dose of vaccination. Neutralizing antibodies and cellular immunity were absent in four of the eight post-HTx patients and one with single ventricle CHD. There was no correlation between the anti-spike and neutralizing antibody titers and interferon-gamma levels. When comparing the clinical characteristics of the patients post-HTx who did or did not acquire antibodies, there was no significant difference in the immunosuppressant types and trough levels. CONCLUSIONS: SARS-CoV-2 mRNA vaccine has efficient immunogenicity for adolescents with CHD, IPAH, and DCM. Half of post-HTx patients could not acquire sufficient humoral immunity.

Atomic force microscopy identifies the alteration of rheological properties of the cardiac fibroblasts in idiopathic restrictive cardiomyopathy.

Restrictive cardiomyopathy (RCM) is a rare disease characterized by increased ventricular stiffness and preserved ventricular contraction. Various sarcomere gene variants are known to cause RCM; however, more than a half of patients do not harbor such pathogenic variants. We recently demonstrated that cardiac fibroblasts (CFs) play important roles in inhibiting the diastolic function of cardiomyocytes via humoral factors and direct cell-cell contact regardless of sarcomere gene mutations. However, the mechanical properties of CFs that are crucial for intercellular communication and the cardiomyocyte microenvironment remain less understood. In this study, we evaluated the rheological properties of CFs derived from pediatric patients with RCM and healthy control CFs via atomic force microscopy. Then, we estimated the cellular modulus scale factor related to the cell stiffness, fluidity, and Newtonian viscosity of single cells based on the single power-law rheology model and analyzed the comprehensive gene expression profiles via RNA-sequencing. RCM-derived CFs showed significantly higher stiffness and viscosity and lower fluidity compared to healthy control CFs. Furthermore, RNA-sequencing revealed that the signaling pathways associated with cytoskeleton elements were affected in RCM CFs; specifically, cytoskeletal actin-associated genes (ACTN1, ACTA2, and PALLD) were highly expressed in RCM CFs, whereas several tubulin genes (TUBB3, TUBB, TUBA1C, and TUBA1B) were down-regulated. These results implies that the signaling pathways associated with cytoskeletal elements alter the rheological properties of RCM CFs, particularly those related to CF-cardiomyocyte interactions, thereby leading to diastolic cardiac dysfunction in RCM.

Prenatal diagnosis of a coronary-to-pulmonary artery fistula in a fetus with pulmonary atresia and ventricular septal defect.

Pulmonary atresia and ventricular septal defect (PA/VSD) demonstrate a wide variety of pulmonary and coronary artery abnormalities; additionally, coronary-to-pulmonary artery fistula (CPAF) is a rare manifestation of PA/VSD and is seldom detected during pregnancy. In this report, we present a case of prenatal diagnosis of CPAF in PA/VSD and impactful images in a neonate, which were obtained using fetal echocardiography and postnatal electrocardiography-gated 320-row CT. Prenatal diagnosis of CPAF can facilitate the provision of better therapeutic strategies after birth.

Topiroxostat versus allopurinol in patients with chronic heart failure complicated by hyperuricemia: A prospective, randomized, open-label, blinded-end-point clinical trial.

BACKGROUND: The benefits of xanthine oxidase inhibitors to chronic heart failure (CHF) patients is controversial. We investigated the beneficial effects of a novel xanthine oxidoreductase inhibitor, topiroxostat, in patients with CHF and hyperuricemia (HU), in comparison to allopurinol. METHODS AND RESULTS: The prospective, randomized open-label, blinded-end-point study was performed in 141 patients with CHF and HU at 4 centers. Patients were randomly assigned to either topiroxostat or allopurinol group to achieve target uric acid level ≤6.0 mg/dL. According to the protocol, 140 patients were followed up for 24 weeks. Percent change in ln (N-terminal-proB-type natriuretic peptide) at week 24 (primary endpoint) was comparable between topiroxostat and allopurinol groups (1.6±8.2 versus -0.4±8.0%; P = 0.17). In the limited number of patients with heart failure with reduced ejection fraction (HFrEF) (left ventricle ejection fraction <45%), ratio of peak early diastolic flow velocity at mitral valve leaflet to early diastolic mitral annular motion velocity (E/e') decreased in topiroxostat group, but not in allopurinol group. Urinary 8-hydroxy-2'-deoxyguanosine and L-type fatty acid-binding protein levels increased and osmolality decreased significantly in allopurinol group, while these changes were less or absent in topiroxostat group. In allopurinol group HFrEF patients, additional to the increases in these urinary marker levels, urinary creatinine levels decreased, with no change in clearance, but not in topiroxostat group. CONCLUSIONS: Compared with allopurinol, topiroxostat did not show great benefits in patients with CHF and HU. However, topiroxostat might have potential advantages of reducing left ventricular end-diastolic pressure, not worsening oxidative stress in proximal renal tubule, and renoprotection over allopurinol in HFrEF patients.

Riociguat can ameliorate bronchopulmonary dysplasia in the SU5416 induced rat experimental model.

BACKGROUND: Bronchopulmonary dysplasia (BPD) is a chronic lung disease in premature neonates. Classical BPD is caused by hyperoxia and high-pressure mechanical ventilation, whereas BPD in recent era is caused by impaired pulmonary angiogenesis and alveolarization in extreme prematurity. Although sildenafil was reported to be effective in a hyperoxia-induced rat BPD model, several clinical trials could not demonstrate any significant improvement in the respiratory statuses of BPD infants. Riociguat is a soluble guanylate cyclase stimulator that increases cyclic guanosine monophosphate activity in a nitric oxide independent manner. However, a beneficial effect in BPD has not been established yet. METHODS AND RESULTS: We established BPD model in rats by injection of SU5416 on day 1 followed by maintenance under normoxia, which resulted in oversimplified alveoli, sparse pulmonary capillary vessels, severe pulmonary hypertension, and growth retardation, which mimicked the features observed in recent clinical management of BPD. We administered riociguat from day 10, when BPD rats exhibited growth retardation. Histological analyses demonstrated that riociguat treatment significantly but partially ameliorated lung alveolarization, vascularization, and pulmonary hypertension. However, the survival rate was not significantly improved by riociguat treatment. CONCLUSIONS: Riociguat could ameliorate pulmonary alveolarization, vascularization, and hypertension in the SU5416 induced BPD rat model, but could not improve the overall survival.

Pharmacological Alteration of Cellular Mechanical Properties in Pulmonary Arterial Smooth Muscle Cells of Idiopathic Pulmonary Arterial Hypertension.

BACKGROUND: Idiopathic pulmonary arterial hypertension (IPAH) is a progressive disease caused by vascular remodeling of the pulmonary arteries with elevated pulmonary vascular resistance. Recently, various pulmonary vasodilator drugs have become available in the clinical field, and have dramatically ameliorated the prognosis of IPAH. However, little is known about how the mechanical properties of pulmonary arterial smooth muscle cells (PASMCs) are altered under drug supplementation. METHODS: Atomic force microscopy (AFM) was used to investigate the mechanical properties of PASMCs derived from a patient with IPAH (PAH-PASMCs) and a healthy control (N-PASMCs) which received the supplementation of clinically used drugs for IPAH: sildenafil, macitentan, and riociguat. RESULTS: PASMCs derived from PAH-PASMCs were stiffer than those derived from N-PASMCs. With sildenafil treatment, the apparent Young's modulus (E 0) of cells significantly decreased in PAH-PASMCs but remained unchanged in N-PASMCs. The decrease in E 0 of PAH-PASMCs was also observed in macitentan and riociguat treatment. The stress relaxation AFM revealed that the decrease in E 0 of PAH-PASMCs resulted from a decrease in the cell elastic modulus and/or increase in cell fluidity. The combination treatment of macitentan and riociguat showed an additive effect on cell mechanical properties, implying that this clinically accepted combination therapy for IPAH influences the intracellular mechanical components. CONCLUSIONS: Pulmonary vasodilator drugs affect the mechanical properties of PAH-PASMCs, and there exists a mechanical effect of combination treatment on PAH-PASMCs.

Innovative therapeutic strategy using prostaglandin I2 agonist (ONO1301) combined with nano drug delivery system for pulmonary arterial hypertension.

Clinical outcomes of pulmonary arterial hypertension (PAH) may be improved using targeted delivery system. We investigated the efficacy of ONO1301 (prostacyclin agonist) nanospheres (ONONS) in Sugen5416/hypoxia rat models of PAH. The rats were injected with saline (control) or ONONS (n = 10, each) on days 21 and 28, respectively. Hepatocyte growth factor (HGF)-expressing fibroblasts and inflammatory cytokines were measured. Cardiac performance was assessed and targeted delivery was monitored in vivo, using Texas red-labeled nanoparticles. Compared with control, HGF-expressing fibroblasts and HGF expression levels were significantly higher in the ONONS group, while the levels of interleukin-6, interleukin-1ß, transforming growth factor-ß, and platelet-derived growth factor were lower. Histological assessment revealed significant amelioration of the percent medial wall thickness in pulmonary vasculature of rats in the ONONS group. Rats in the ONONS group showed decreased proliferating cell nuclear antigen-positive smooth muscle cells and improved right ventricle pressure/left ventricle pressure. No difference was seen in the accumulation of Texas red-labeled nanoparticles in the brain, heart, liver, and spleen between PAH and normal rats. However, a significant area of nanoparticles was detected in the lungs of PAH rats. ONONS effectively ameliorated PAH, with selective delivery to the damaged lung.