Everolimus-Eluting Biodegradable Abluminal Coating Stent versus Durable Conformal Coating Stent: Termination of the Inflammatory Response Associated with Neointimal Healing in a Porcine Coronary Model.

OBJECTIVES: We evaluated the effect of the different carrier systems on early vascular response through histological analysis and scanning electron microscopy using a porcine model. BACKGROUND: Although Synergy™ and Promus PREMIER™ share an identical stent material and drug elution (everolimus), they use different drug carrier systems: biodegradable abluminal coating polymer or durable conformal coating polymer, respectively. However, data regarding the impact of the different coating systems on vessel healing are currently limited. METHODS: Twelve Synergy™ and Promus PREMIER™ were implanted in 12 swine. Histopathological analysis of the stented segments was performed on the 2nd and 14th days after implantation. Morphometric analysis of the inflammation and intimal fibrin content was also performed. RESULTS: On the 2nd day, neointimal thickness, percentage of neointimal area, and inflammatory and intimal fibrin content scores were not significantly different between the two groups. On the 14th day, the inflammatory and intimal fibrin content scores were significantly lower in Synergy™ versus those observed in Promus PREMIER™. In Synergy™, smooth muscle cells were found and the neointimal layers were smooth. In contrast, inflammatory cells were observed surrounding the struts of Promus PREMIER™. CONCLUSIONS: These results demonstrate that termination of reactive inflammation is accelerated after abluminal coating stent versus implantation of conformal coating stent.

Characteristics of induced pluripotent stem cells from clinically divergent female monozygotic twins with Danon disease.

RATIONALE: Induced pluripotent stem cells (iPSCs) have been generated from patients with various forms of disease, including Danon disease (DD); however, few reports exist regarding disease-specific iPSCs derived from clinically divergent monozygotic twins. OBJECTIVE: We examined the characteristics of iPSCs and iPSC-derived cardiomyocytes (iPSC-CMs) generated from clinically divergent monozygotic female twins with DD. METHODS AND RESULTS: We generated iPSCs derived from T-cells isolated from clinically divergent, 18-year-old female twins with DD harboring a mutation in LAMP2 at the intron 6 splice site (IVS6+1_4delGTGA). Two divergent populations of iPSCs could prepare from each twin despite of their clinical divergence: one with wild-type LAMP2 expression (WT-iPSCs) and a second with mutant LAMP2 expression (MT-iPSCs). The iPSCs were differentiated into iPSC-CMs and then autophagy failure was observed only in MT-iPSC-CMs by electron microscopy, tandem fluorescent-tagged LC3 analysis, and LC3-II western blotting. Under these conditions, X-chromosome inactivation (XCI) was determined by PCR for the (CAG)n repeat in the androgen receptor gene, revealing an extremely skewed XCI pattern with the inactivated paternal wild-type and maternal mutant X-chromosomes in MT-iPSCs and WT-iPSCs, respectively, from each twin. CONCLUSION: Regardless of their clinical differences, we successfully established two sets of iPSC lines that expressed either wild-type or mutant LAMP2 allele from each monozygotic twin with DD, of which only the populations expressing mutant LAMP2 showed autophagic failure.

Application of an enhanced device to transluminal retrieval of malappositioned coronary stents: An experimental study.

OBJECTIVES: This study investigated the application of a novel enhanced device to retrieval of deployed stents in a porcine coronary model. BACKGROUND: Recurrence of in-stent restenosis and stent thrombosis still remains to be resolved. Under these conditions, it is sometimes necessary to retrieve malfunctional stents responsible for thrombosis. However, few data exist regarding the feasibility and safety of retrieval device use in previously deployed coronary stents. METHODS: We have developed an enhanced device consisting of an asymmetric forceps, conducting shaft (1.6 mm diameter, 150 cm length), and control handle. Bare-metal stents (3 mm diameter) were implanted in four pigs to create a malapposition model. Coronary artery injury was evaluated by intravascular ultrasound (IVUS) and histological imaging on the first and 14th days. RESULTS: The device was delivered to the coronary artery using the existing catheter (7 Fr). After opening the forceps, the blade was forced into the space between the vessel wall and the stent, and the stent struts were then grasped with the forceps. This was then pulled back into the catheter, still grasping the stent struts with the forceps. All stents were successfully retrieved by this method (n = 4). On the first day, no apparent vessel wall injury was detectable by IVUS, although histological findings revealed damage to endothelial monolayer on retrieval of deployed stent. On the 14th day, mild intimal thickening was observed by IVUS and histology. CONCLUSIONS: These results demonstrate that the present device can be applied to transluminal retrieval of acquired malappositioned coronary stents.

Early endothelialization associated with a biolimus A9 bioresorbable polymer stent in a porcine coronary model.

Although Nobori®, with a bioresorbable polymer and biolimus A9 abluminal coating, has unique characteristics, few data exist regarding endothelialization early after implantation. Fifteen Nobori® and 14 control bare-metal stents (S-stent™) were implanted in 12 pigs. Histopathology of stented segments, inflammation, and intimal fibrin content was evaluated on the 2nd and 14th day after implantation. On the 2nd day, endothelial cells were morphologically and immunohistologically confirmed on the surface of both stents, although some inflammatory cells might be involved. Stent surface endothelialization evaluated with a scanning electron microscope showed partial cellular coverage in both stents. On the 14th day, neointimal thickness and percentage of the neointimal area were significantly lower in Nobori® than in S-stent™ (51.4 ± 4.5 vs. 76.4 ± 23.6 µm, p < 0.05 and 10.8 ± 2.6 vs. 14.1 ± 4.2%, p < 0.01). No significant differences were found in these parameters on the 2nd day (17.3 ± 14.9 vs. 26.7 ± 13.6 µm and 3.7 ± 3.0 vs. 6.7 ± 3.7%), in inflammatory and intimal fibrin content scores. These results demonstrate that endothelialization could occur early after Nobori® implantation with similar inflammatory reaction to bare-metal stents, probably contributing to low frequency of in-stent thrombosis and restenosis.

Function and Immunogenicity of Gene-corrected iPSC-derived Hepatocyte-Like Cells in Restoring Low Density Lipoprotein Uptake in Homozygous Familial Hypercholesterolemia.

Gene correction of induced pluripotent stem cells (iPSCs) has therapeutic potential for treating homozygous familial hypercholesterolemia (HoFH) associated with low-density lipoprotein (LDL) receptor (LDLR) dysfunction. However, few data exist regarding the functional recovery and immunogenicity of LDLR gene-corrected iPSC-derived hepatocyte-like cells (HLCs) obtained from an HoFH patient. Therefore, we generated iPSC-derived HLCs from an HoFH patient harbouring a point mutation (NM_000527.4:c.901 G > T) in exon 6 of LDLR, and examined their function and immunogenicity. From the patient's iPSCs, one homozygous gene-corrected HoFH-iPSC clone and two heterozygous clones were generated using the CRISPR/Cas9 method. Both types of iPSC-derived HLCs showed recovery of the function of LDL uptake in immunofluorescence staining analysis. Furthermore, these gene-corrected iPSC-derived HLCs showed little immunogenicity against the patient's peripheral blood mononuclear cells in a cell-mediated cytotoxicity assay. These results demonstrate that LDL uptake of iPSC-derived HLCs from HoFH can be restored by gene correction without the appearance of further immunogenicity, suggesting that gene-corrected iPSC-derived HLCs are applicable to the treatment of HoFH.

Determination of Early and Late Endothelial Progenitor Cells in Peripheral Circulation and Their Clinical Association with Coronary Artery Disease.

The clinical implications of early and late endothelial progenitor cells (EPCs) in coronary artery disease (CAD) remain unclear. We investigated endothelial dysfunction in CAD by simultaneously examining early and late EPC colony formation and gene expression of specific surface markers in EPCs. EPCs were extracted from a total of 83 subjects with (n = 47) and without (n = 36) CAD. Early and late EPC colonies were formed from mononuclear cells extracted from peripheral blood. We found that fewer early EPC colonies were produced in the CAD group (7.2 ± 3.l/well) than those in the control group (12.4 ± 1.4/well, p < 0.05), and more late EPC colonies were produced in the CAD group (0.8 ± 0.2/well) than those in the control group (0.25 ± 0.02/well, p < 0.05). In the CAD group, the relative expression of CD31 and KDR of early and late EPCs was lower than in the control group. These results demonstrate that CAD patients could have increased late EPC density and that early and late EPCs in CAD patients exhibited immature endothelial characteristics. We suggest that changes in EPC colony count and gene expression of endothelial markers may have relation with development of CAD.

Increased extent of myocardial fibrosis in genotyped hypertrophic cardiomyopathy with ventricular tachyarrhythmias.

BACKGROUND: Occurrence of malignant ventricular tachyarrhythmias such as ventricular tachycardia and fibrillation (VT/VF) in hypertrophic cardiomyopathy (HCM) can be related to the extent of myocardial fibrosis. Although late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) imaging has been used to detect myocardial fibrosis, few data exist regarding relationships between CMR-determined myocardial fibrosis and VT/VF in genotyped HCM populations. OBJECTIVE: We retrospectively investigated whether the extent of LGE can be increased in HCM patients with VT/VF compared to those without VT/VF in the genotyped HCM population. METHODS AND RESULTS: We studied 35 HCM patients harboring sarcomere gene mutations (TNNI3=22, MYBPC3=12, MYH7=1) who underwent both CMR imaging and 24-h ambulatory electrocardiographic monitoring. VT/VF were identified in 6 patients (2 men, mean age 55.0 years). The extent of LGE was significantly increased in patients with VT/VF (n=6) compared with those without VT/VF (n=29) (18.6±14.4% vs. 8.3±11.4%, p=0.04), although the LGE extent was not an independent predictor for the occurrence of VT/VF. Applying a cut-off point ≥3.25%, episodes of VT/VF were identified with a sensitivity of 100%, specificity of 51.7%, positive predictive value of 30%, negative predictive value of 100%, and the area under the curve of 0.767 (95% confidence interval: 0.590-0.944). CONCLUSION: These results demonstrate that myocardial fibrosis determined by CMR imaging may be increased in genotyped HCM patients with episodes of VT/VF. A further prospective study will be needed to clarify the association between the LGE extent and arrhythmic events in HCM patients harboring sarcomere gene mutations.

Pulmonary hypertension associated with veno-occlusive disease in systemic sclerosis: Insight into the mechanism of resistance to vasodilator.

We report a case with pulmonary veno-occlusive disease (PVOD) associated with systemic sclerosis which exhibits strong resistance to pulmonary vasodilator. A 55-year-old female with severe pulmonary hypertension was admitted to our hospital to be introduced to epoprostenol infusion therapy. She was diagnosed as having pulmonary arterial hypertension (PAH) associated with systemic sclerosis at the age of 51. Several aggressive treatments with pulmonary vasodilators, including oral prostaglandin, endothelin receptor antagonists, and phosphodiesterase 5 inhibitors, failed to improve her symptoms. We introduced continuous intravenous epoprostenol therapy from 2 µg/kg/min for her. However, pulmonary edema appeared and worsened in a dose-dependent manner. We made a diagnosis of PVOD clinically at that time. Thereafter, pulmonary edema gradually disappeared consistent with the reduction of the dose of epoprostenol infusion. She died of renal failure and infection 4 months after the introduction of epoprostenol infusion therapy. A histological examination revealed severe stenosis and occlusions of pulmonary veins as well as pulmonary arteries over a wide area. We suggest that prevalence of veno-occlusive type of disease could be one of the major mechanisms of less responsive or even refractory to pulmonary vasodilator therapies in patients with PAH associated with connective tissue disease.