Lysyl hydroxylase 1 (LH1) deficiency promotes angiotensin II (Ang II)-induced dissecting abdominal aortic aneurysm.

Rationale: The progressive disruption of extracellular matrix (ECM) proteins, particularly early elastin fragmentation followed by abnormalities in collagen fibril organization, are key pathological processes that contribute to dissecting abdominal aortic aneurysm (AAA) pathogenesis. Lysyl hydroxylase 1 (LH1) is essential for type I/III collagen intermolecular crosslinking and stabilization. However, its function in dissecting AAA has not been explored. Here, we investigated whether LH1 is significantly implicated in dissecting AAA progression and therapeutic intervention. Methods and Results: Sixteen-week-old male LH1-deficient and wild-type (WT) mice on the C57Bl/6NCrl background were infused with angiotensin II (Ang II, 1000 ng/kg per minute) via subcutaneously implanted osmotic pumps for 4 weeks. Ang II increased LH1 levels in the abdominal aortas of WT mice, whereas mice lacking LH1 developed dissecting AAA. To evaluate the related mechanism, we performed whole-transcriptomic analysis, which demonstrated that LH1 deficiency aggravated gene transcription alterations; in particular, the expression of thrombospondin-1 was markedly upregulated in the aortas of LH1-deficient mice. Furthermore, targeting thrombospondin-1 with TAX2 strongly inhibited the proinflammatory process, matrix metalloproteinase (MMP) activity and vascular smooth muscle cells (VSMCs) apoptosis, ultimately decreasing the incidence of dissecting AAA. Restoration of LH1 protein expression in LH1-deficient mice by intraperitoneal injection of an adeno-associated virus normalized thrombospondin-1 levels, subsequently alleviating dissecting AAA formation and preserving aortic structure and function. Consistently, in human AAA specimens, decreased LH1 expression was associated with increased thrombospondin-1 levels. Conclusions: LH1 deficiency contributes to dissecting AAA pathogenesis, at least in part, by upregulating thrombospondin-1 expression, which subsequently enables proinflammatory processes, MMP activation and VSMCs apoptosis. Our study provides evidence that LH1 is a potential critical therapeutic target for AAA.

Prevalence and Clinical Characteristics of Fabry Disease in Chinese Patients With Hypertrophic Cardiomyopathy.

BACKGROUND: The prevalence of Fabry disease (FD) in Chinese patients with hypertrophic cardiomyopathy (HCM) is unclear. We aimed to evaluate the prevalence, clinical characteristics, and outcomes of FD in Chinese patients with HCM. METHODS: Of 217 patients with HCM, FD probands were screened by next-generation sequencing at Fuwai Hospital. Medical data from α-galactosidase A activity, electrocardiography, echocardiography, coronary angiography, cardiac magnetic resonance, pathological examination, and follow up was analyzed. RESULTS: Two FD probands were observed (0.93% of patients with HCM), both of which were diagnosed with symptomatic obstructive HCM at 49 years of age. One proband had a GLA mutation (c.887T>C [p.M296T]) with a late-onset cardiac variant, which was characterized by dual ventricular hypertrophy and conduction disease with a permanent pacemaker. The other patient had a GLA mutation (c.758T>C [p.I253T]) with a classic phenotype and dual ventricular hypertrophy, atrioventricular block, renal failure, and recurrent cerebral infarction. Both probands had late gadolinium enhancement mainly in the basal segment of the inferolateral wall. Follow up revealed no exertional symptoms or outflow obstruction after surgical septal myectomy in the two probands, and stable renal function was observed after 6 months of migalastat therapy in the later one. A family study revealed six female carriers and three sudden cardiac deaths. CONCLUSIONS: FD is not uncommon in Chinese patients with HCM. Multiple organic involvement, dual ventricular hypertrophy, and conduction disease provide clinical clues for suspected FD, and early genetic screening is necessary. Surgical septal myectomy and migalastat improve the long-term prognosis of patients with FD.

Effects of CMYA1 overexpression on cardiac structure and function in mice.

CMYA1 (cardiomyopathy-associated protein 1, also termed Xin) localizes to the intercalated disks (ICDs) of the myocardium and functions to maintain ICD structural integrity and support signal transduction among cardiomyocytes. Our previous study showed that CMYA1 overexpression impairs the function of gap junction intercellular communication processes. Successful model generation was verified based on PCR, western blot analysis, immunohistochemistry, and immunofluorescence analysis. Myocardial CMYA1 expression was confirmed at both the mRNA and the protein levels in the CMYA1-OE transgenic mice. Masson's trichrome staining and electron microscopy revealed myocardial fibrosis and uneven bead width or the interruption of ICDs in the hearts of the CMYA1-OE transgenic mice. Furthermore, the Cx43 protein level was reduced in the CMYA1-OE mice, and co-immunoprecipitation assays of heart tissue protein extracts revealed a physical interaction between CMYA1 and Cx43. Electrocardiogram analysis enabled the detection of an obvious ventricular bigeminy for the CMYA1-OE mice. In summary, analysis of our mouse model indicates that elevated CMYA1 levels may induce myocardial fibrosis, impair ICDs, and downregulate the expression of Cx43. The observed ventricular bigeminy in the CMYA1-OE mice may be mediated by the reduced Cx43 protein level.

Elevated myocardial SORBS2 and the underlying implications in left ventricular noncompaction cardiomyopathy.

BACKGROUND: Left ventricular noncompaction cardiomyopathy (LVNC) is a hereditary heart disease characterized by an excessive trabecular meshwork of deep intertrabecular recesses within the ventricular myocardium. The guidelines for management of LVNC patients aim to improve quality of life by preventing cardiac heart failure. However, the mechanism underlying LVNC-associated heart failure remains poorly understood. METHODS: Using protein mass spectrometry analysis, we established that Sorbin And SH3 Domain Containing 2 (SORBS2) is up-regulated in LVNC hearts without changes to structure proteins. We conducted in vivo experiments wherein the heart tissues of wild-type mice were injected with an AAV9 vector to overexpress SORBS2, followed by analysis using echocardiography, T-tubule analysis and Ca2+ imaging to identify functional and morphological changes. In addition, we analyzed the function and structure of SORBS2 overexpressing human embryonic stem cell (hESC) derived cardiomyocytes (hESC-CM) via immunoblotting, immunohistochemistry, immunofluorescence, and confocal Ca2+ imaging. FINDINGS: LVNC myocardial tissues feature strongly elevated expression of SORBS2, microtubule densification and redistribution of Junctophilin 2 (JP2). SORBS2 interacts with ß-tubulin, promoting its polymerization in 293T cells and hESC-derived CMs. In vivo, cardiac dysfunction, ß-tubulin densification, JP2 translocation, T-tubule disorganization and Ca2+ handling dysfunction were observed in mice overexpressing SORBS2. INTERPRETATION: We identified a novel mechanism through which SORBS2 interacts with ß-tubulin and promotes microtubule densification, eventually effecting JP2 distribution and T-tubule, potentially contributing to heart failure in LVNC disease. FUND: This work was supported by a CAMS Initiative for Innovative Medicine grant (CAMS-I2M, 2016-I2M-1-015 to Y.J.Wei).

[Pathologic markers for evaluation of reversibility in pulmonary hypertension related to congenital heart disease].

OBJECTIVE: To assess the pathologic markers for evaluation of reversibility in pulmonary hypertension (PAH) related to congenital heart disease. METHODS: Twenty-eight patients with congenital heart disease complicated by PAH were subclassified into reversible pulmonary hypertension (RPAH) and irreversible pulmonary hypertension (IPAH), according to post-operative mean pulmonary artery pressure (MPAP). Pulmonary vascular lesion was analyzed according to Ruan's method. Mean medium thickness percent, mean medium area percent and pulmonary arteriolar density were measured by quantitative morphometry. Immunohistochemical study for transgelin and filamin A was carried out. RESULTS: Amongst the 28 cases studied, 24 were RPAH and 4 were IPAH. Of the 24 patients with RPAH, 13 (54.2%, 13/24) had pulmonary vascular lesion of grade 0, 9 (37.5%, 9/24) of grade 1 and 2 (8.3%, 2/24) of grade 2. Of the 4 patients with IPAH, 1 had lesion of grade 1, 1 of grade 2 and 2 of grade 3. Both preoperative and postoperative MPAP were higher in IPAH patients than that in RPAH patients[(53.3±23.4) mmHg versus (34.1±12.7) mmHg, P=0.020 and (35.0±8.8) mmHg versus (17.8±3.9) mmHg, P<0.01]. Compared to patients with pulmonary vascular lesion of grades 0 and 1, the preoperative MPAP in patients with grades 2 and 3 showed no significant difference, but the postoperative MPAP was higher (P<0.05 or 0.01). Compared to control group, mean medium thickness percent and mean medium area percent were significantly higher in RPAH and IPAH categories (12.0±3.5, 8.5±2.0 versus 5.7±1.0, P<0.01 and 55.8±11.1, 49.0±9.4 versus 34.0±5.5, P<0.01). Mean medium thickness percent was significantly higher in IPAP group than that in RPAH group (12.0±3.5 versus 8.5±2.0, P=0.001). Correlation analysis demonstrated that mean medium thickness percent and mean medium area percent had positive correlation with preoperative and postoperative MPAP. There was no correlation between grading of pulmonary vascular lesion and reversibility. Transgelin and filamin A had stronger staining in pulmonary vascular smooth muscle cells in IPAH than those in RPAH and controls(P<0.05). CONCLUSIONS: Pathologic assessment of lung biopsy remains the gold standard for evaluation of the reversibility in PAH related to congenital heart disease. Mean medium thickness percent, mean medium area percent and immunoreactivity for transgelin and filamin A are useful parameters.

Three-dimensional phase-sensitive inversion-recovery Turbo FLASH sequence for the assessment of left ventricular myocardial scar in swine.

OBJECTIVES: We sought to evaluate the feasibility and accuracy of free-breathing three-dimensional (3D) phase-sensitive inversion-recovery (PSIR) Turbo FLASH sequence for noninvasive assessment of left ventricular myocardial scar in swine models. MATERIALS AND METHODS: Nine Chinese minipigs with experimentally induced acute myocardial infarction were studied. At 1 week and the study endpoint 4 weeks after myocardial infarction surgery, the 3D and 2D contrasted cardiac magnetic resonance (CMR) imaging were performed randomly by using a 1.5 T clinical MR imaging system. Comparisons of myocardial scar volume (in cubic centimeters), scar transmurality (on a 5 points scale) and image quality (on a 4 points Likert scale) were performed by using the Pearson correlation and Bland-Altman analysis (for myocardial scar volume) or κ statistics (for transmurality) or Wilcoxon signed rank test (for image quality). RESULTS: In 6 of the 9 pigs, all procedures were successfully completed. In these pigs, a total of 48 segments with myocardial scars were detected by both 3D and 2D sequences, and there was good agreement for classification of scar transmurality (κ=0.930). The scar volume determined by triphenyltetrazolium chloride (TTC) staining (3.52 ± 1.40 cm(3)) showed a good correlation with both 3D (3.54 ± 1.36 cm(3), r=0.957, P=0.003) and 2D sequence (3.53 ± 1.26 cm(3), r=0.942, P=0.005) at 4 weeks. And there were good correlation between scar volumes obtained from 3D and 2D techniques (r=0.859, P<0.001) at both time points. Both 3D and 2D images detected a small reduction of scar volume from week 1 to week 4 by a factor of 1.179 and 1.176, respectively. Although slightly more artifacts were observed on 2D PSIR images, the overall image quality was not significantly different between the two sequences (3.17 ± 0.83 for 2D vs. 3.25 ± 0.75 for 3D, P =0.655). CONCLUSIONS: The free-breathing 3D PSIR Turbo FLASH sequence enables accurate assessment of left ventricular myocardial scar.

[Clinico-pathological characteristics of infective endocarditis associated with congenital heart disease: an analysis of 74 cases in single center].

OBJECTIVE: To assess the changing profile of infective endocarditis (IE) in patients with congenital heart disease (CHD) from 1998 to 2009 in our hospital. METHODS: Clinical characteristics of IE patients with CHD underwent surgical treatment during 1998 - 2009 in our hospital were evaluated. The coincidence rate between clinical and pathological diagnosis were analyzed. RESULTS: There were 74 IE cases associated with CHD during the 12 years, accounting for 33.6% of all patients with IE receiving surgery during this time period. Mean age was higher for patients treated in 2006 - 2009 than patients treated in 2002 - 2005 [(38.7 ± 14.6) years vs. (28.4 ± 12.8) years, P = 0.003].Bicuspid aortic valve (accounting for 52.2%) was the most frequent congenital heart disease and the age of these patients was younger than patients with other congenital heart diseases. IE in CHD affected the left heart structures in 83.8% (62/74) of all cases, 47 in aortic valve (75.8%). Blood cultures were performed in 29.7% of the patients (22/74) and the positive rate was 59.1% (13/22). Streptococci viridans were the most common causative organisms. Echocardiography was performed in all patients and 66.3% echocardiographic records were positive, IE was diagnosed in 53 patients (71.7%) before operation. The operative mortality was 2.7%. CONCLUSION: Congenital heart disease, especially bicuspid aortic valve, is the most common underlying disease for IE. Combined analysis of clinical, echocardiographic and blood culture results are essential for increasing the diagnosis rate of IE.

[Clinical implication of microvasculopathy in patients post heart transplantation].

OBJECTIVE: Assess the clinical implication of microvasculopathy detected by endomyocardial biopsy samples in patients post heart transplantation. METHODS: Light microscopic evaluations were performed in 278 endomyocardial biopsies harvested from 64 patients post heart transplantation for more than one year, microvasculopathy was defined as stenotic endothelial and/or medial disease. RESULTS: The patients with stenotic microvasculopathy were younger than those without microvasculopathy (40.7 ± 15.9 vs. 49.4 ± 8.7, P < 0.05). The mean score of acute cellular rejection (0.83 ± 0.39 vs. 0.37 ± 0.32, P < 0.01) and the numbers of ≥ grade II acute rejection (0.84 ± 0.16 vs. 0.23 ± 0.10, P < 0.01) were significantly greater in stenotic microvasculopathy group compared to those of non-stenotic group. Multivariate regression analysis confirmed that stenotic microvasculopathy is the independent risk factor for the mean acute rejection score (OR = 3.40, 95%CI, 4.62 - 193.07, P < 0.01), but not for the Quilty lesion, coronary heart disease of donor, diabetes mellitus. Angiographically confirmed coronary vasculopathy and cardiac dysfunction (χ(2) = 0.94, P > 0.05 and χ(2) = 2.90, P > 0.05) were similar between microvasculopathy group and non-microvasculopathy group. CONCLUSION: Post heart transplantation microvasculopathy is an immune-mediated phenomenon and associated with higher mean score of acute cellular rejection and higher numbers of ≥ grade II acute rejection but was not the prognostic risk factor for coronary vasculopathy and function reduction after heart transplantation.

[Clinicopathologic analysis of dilated heart in cardiac transplant recipients].

OBJECTIVE: To study the pathologic features of dilated heart in cardiac transplant recipients, with clinicoradiologic correlation. METHODS: Sixty recipient hearts from cardiac transplantation performed in Fuwai Hospital were analyzed by gross examination, histologic observation and electron microscopy. Clinicoradiologic correlation was available in 40 cases. RESULTS: Amongst the 40 cases of dilated heart, 52.5% (21/40) were due to dilated cardiomyopathy, 22.5% (9/40) due to arrhythmogenic right ventricular cardiomyopathy, 15.0% (6/40) due to ischemic cardiomyopathy, and the remaining 10.0% (4/40) due to miscellaneous causes, including local noncompaction of ventricular myocardium, giant cell myocarditis, alcoholic cardiomyopathy and hypertensive cardiomyopathy. The discrepancy rate between clinical and pathologic diagnosis was 37.5% (15/40). The erroneous categories included arrhythmogenic right ventricular cardiomyopathy (7 cases), ischemic cardiomyopathy (5 cases), and giant cell myocarditis (1 case), which were all mistaken clinically as dilated cardiomyopathy. While ischemic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, noncompaction of ventricular myocardium and giant cell myocarditis have distinctive pathologic features, the diagnosis of alcoholic and hypertensive cardiomyopathies required clinicopathologic correlation. Dilated cardiomyopathy due to viral myocarditis was not identified in the cases studied. CONCLUSION: Pathologic examination is essential in analysis of transplant recipient heart and helps to rectify clinical diagnostic discrepancy.