Histone acetyltransferase P300 deficiency promotes ferroptosis of vascular smooth muscle cells by activating the HIF-1α/HMOX1 axis.

BACKGROUND: E1A-associated 300-kDa protein (P300), an endogenous histone acetyltransferase, contributes to modifications of the chromatin landscape of genes involved in multiple cardiovascular diseases. Ferroptosis of vascular smooth muscle cells (VSMCs) is a novel pathological mechanism of aortic dissection. However, whether P300 regulates VSMC ferroptosis remains unknown. METHODS: Cystine deprivation (CD) and imidazole ketone erastin (IKE) were used to induce VSMC ferroptosis. Two different knockdown plasmids targeting P300 and A-485 (a specific inhibitor of P300) were used to investigate the function of P300 in the ferroptosis of human aortic smooth muscle cells (HASMCs). Cell counting kit-8, lactate dehydrogenase and flow cytometry with propidium iodide staining were performed to assess the cell viability and death under the treatment of CD and IKE. BODIPY-C11 assay, immunofluorescence staining of 4-hydroxynonenal and malondialdehyde assay were conducted to detect the level of lipid peroxidation. Furthermore, co-immunoprecipitation was utilized to explore the interaction between P300 and HIF-1α, HIF-1α and P53. RESULTS: Compared with normal control, the protein level of P300 was significantly decreased in HASMCs treated with CD and IKE, which was largely nullified by the ferroptosis inhibitor ferrostatin-1 but not by the autophagy inhibitor or apoptosis inhibitor. Knockdown of P300 by short-hairpin RNA or inhibition of P300 activity by A-485 promoted CD- and IKE-induced HASMC ferroptosis, as evidenced by a reduction in cell viability and aggravation of lipid peroxidation of HASMCs. Furthermore, we found that hypoxia-inducible factor-1α (HIF-1α)/heme oxygenase 1 (HMOX1) pathway was responsible for the impacts of P300 on ferroptosis of HASMCs. The results of co-immunoprecipitation demonstrated that P300 and P53 competitively bound HIF-1α to regulate the expression of HMOX1. Under normal conditions, P300 interacted with HIF-1α to inhibit HMOX1 expression, while reduced expression of P300 induced by ferroptosis inducers would favor HIF-1α binding to P53 to trigger HMOX1 overexpression. Furthermore, the aggravated effects of P300 knockdown on HASMC ferroptosis were largely nullified by HIF-1α knockdown or the HIF-1α inhibitor BAY87-2243. CONCLUSION: Thus, our results revealed that P300 deficiency or inactivation facilitated CD- and IKE-induced VSMC ferroptosis by activating the HIF-1α/HMOX1 axis, which may contribute to the development of diseases related to VSMC ferroptosis.

DEC1 represses cardiomyocyte hypertrophy by recruiting PRP19 as an E3 ligase to promote ubiquitination-proteasome-mediated degradation of GATA4.

Although the pro-hypertrophic role of GATA binding protein 4 (GATA4) during cardiac hypertrophy has been well established, the negative regulatory mechanism to counteract its hyperactivation remains elusive. We hypothesized that the hyperactivation of GATA4 could be a result of loss of interaction between GATA4 with specific suppressors. Using high throughput mass spectrometry technology, we carried out a proteomic screen for endogenous suppressor of GATA4, which disassociated with GATA4 during the hypertrophic response in a cultured cardiac myoblast cell line (H9C2 cells). We identified differentiated embryo chondrocyte 1 (DEC1) negatively regulated the function of GATA4 through physical interaction and negatively regulated cardiac hypertrophy both in vivo and in vitro. Particularly, DEC1 promoted the ubiquitination and proteasome-mediated degradation of GATA4, but did not function as an E3 ligase. Again, using mass spectrometry technology, we systematically identified pre-mRNA processing factor 19 (PRP19) as a newfound E3 ligase, which promoted the K6-linked ubiquitination of GATA4 at its lysine 256. Functional experiments performed in cultured neonatal rat ventricular myocytes and H9C2 cells demonstrated that both DEC1 and PRP19 negatively regulated agonist-induced cardiomyocyte hypertrophic responses. Furthermore, rescue experiments performed in these cells revealed that DEC1 and PRP19 suppressed cardiomyocyte hypertrophy by inhibiting the function of GATA4. Our study thus defined the novel DEC1-PRP19-GATA4 axis to be a previously unknown mechanism in regulating cardiomyocyte hypertrophy. Although GATA4 is indispensable for normal cardiac function, harnessing DEC1- or PRP19-mediated negative regulation to counteract the hyperactivation of GATA4 might serve as a novel therapeutic strategy for pathological cardiac hypertrophy.

Outcomes of intramural hematoma involving the ascending aorta and extending into the descending thoracic aorta.

OBJECTIVE: The optimal treatment of intramural hematoma (IMH) involving the ascending aorta remains controversial. This study aimed to analyze the results of the management of patients with acute IMH involving the ascending aorta and extending into the descending thoracic aorta, to compare outcomes of descending thoracic endovascular aortic repair (TEVAR) with that of medical therapy (MT), and to assess the risk factors associated with adverse aortic events. METHODS: We retrospectively analyzed all patients diagnosed with acute IMH involving the ascending aorta and extending into the descending thoracic aorta from January 2012 to December 2019. The primary end points during follow-up were aortic disease-related death and adverse aorta-related events that required surgical or endovascular treatment, such as aortic rupture, the progression of aortic disease, or endoleak. RESULTS: We identified a total of 135 patients with acute IMH involving the ascending aorta and extending into the descending thoracic aorta, of whom 104 underwent descending TEVAR (group 1) and 31 were managed with MT (group 2). Freedom from adverse aorta-related events at 1, 3, and 5 years was significantly higher for patients who underwent descending TEVAR compared with those managed with MT (89.2%, 88.2%, and 84.0% vs 74.2%, 74.2%, and 74.2%, respectively; P = .026). The 1-, 3-, and 5-year survival rates for patients in the descending TEVAR group was 100%, 100%, and 100%, respectively, which was significantly higher than the survival of the MT group: 93.5%, 93.5%, and 81.9%, respectively (P = .002). On a univariate analysis among patients receiving MT, those who suffered adverse aorta-related events showed a higher prevalence of renal insufficiency (55.6% vs 9.1%; P = .003). In MT patients, multivariate analysis showed that renal insufficiency was the only independent risk factor associated with adverse aorta-related events (hazard ratio, 8.691; 95% confidence interval, 2.056-36.737; P = .003). CONCLUSIONS: Based on our study, compared with MT, descending TEVAR might be the more favorable treatment for patients with IMH involving the ascending aorta and extending into the descending thoracic aorta. Patients with renal insufficiency are more likely to experience adverse aorta-related events, which implies the need for subsequent intervention or an increased risk of mortality. The risk factor would be helpful for clinical decision-making.

Back-Table Modified Stent-Graft for Endovascular Repair of Ascending Aorta.

OBJECTIVES: To investigate the effectiveness of modified stent-grafts (SGs) for the management of ascending aortic pathologies. MATERIALS AND METHODS: From January 2015 to December 2019, 31 individuals were treated by ascending aortic endovascular repair with a back-table modified SG for acute (n=4) or chronic (n=1) type A aortic dissections, penetrating aortic ulcers (n=18), pseudoaneurysms (n=2), anastomotic fistula (n=1), and endoleaks after thoracic endovascular aortic repair (TEVAR) (n=5). The commercially available thoracic aortic SGs were modified with a fenestration or truncation technique on the back-table according to aortography during the operation. RESULTS: The 30-day mortality and aorta-related mortality rates were 12.9% and 6.5%, respectively. There were 2 strokes, 3 respiratory insufficiencies, and 6 endoleaks during hospitalization. During a mean follow-up of 28.8±16.6 months, the overall survival rates at 1 year and 3 years were both 80.6%. Free from adverse event rates at 1 year and 3 years were 88.9% and 84.7%, respectively. There were 2 deaths during follow-up: One patient died of cachexia 1 month after discharge, and the other patient died of acute myocardial infarction 3 months after discharge. One patient with a pseudoaneurysm underwent open ascending aorta replacement 3 months after discharge for a type Ia endoleak. Another patient suffered from cerebellar infarction 17 months after discharge. CONCLUSION: The modified SG for endovascular repair of the ascending aorta is a practicable alternative and presents acceptable outcomes in high-risk patients.

Aortic root aortopathy in bicuspid aortic valve associated with high genetic risk.

BACKGROUND: The bicuspid aortic valve (BAV) is prone to ascending aortic dilatation (AAD) involving both the tubular segment and the aortic root. The genetic factor was proposed as one of the most important mechanisms for AAD. We hypothesized that the rare genetic variants mainly contribute to the pathogenesis of aortic roots in affected individuals. METHODS: The diameter of aortic root or ascending aorta ≥ 40 mm was counted as AAD. The targeted next-generation sequencing of 13 BAV-associated genes were performed on a continuous cohort of 96 unrelated BAV patients. The rare variants with allele frequency < 0.05% were selected and analyzed. Variants frequency was compared against the Exome aggregation consortium database. The pathogenicity of the genetic variants was evaluated according to the American College of Medical Genetics and Genomics guidelines. RESULTS: A total of 27 rare nonsynonymous coding variants involving 9 genes were identified in 25 individuals. The burden analysis revealed that variants in GATA5, GATA6, and NOTCH1 were significantly associated with BAV. Eighty percent of the pathogenic variants were detected in root group. The detection rate of rare variants was higher in root dilatation group (71.4%) compared with normal aorta (29.0%) and tubular dilatation groups (29.6%) (P = 0.018). The rare variant was identified as the independent risk factor of root dilatation [P = 0.014, hazard ratio = 23.9, 95% confidence interval (1.9-302.9)]. CONCLUSIONS: Our results presented a broad genetic spectrum in BAV patients. The rare variants of BAV genes contribute the most to the root phenotype among BAV patients.

Moderate Hypothermic Circulatory Arrest with Antegrade Cerebral Perfusion for Rapid Total Arch Replacement in Acute Type A Aortic Dissection.

BACKGROUND: The optimal hypothermic level during circulatory arrest is controversial. The aim of our study was to comprehensively assess the impact of moderate hypothermic circulatory arrest with antegrade cerebral perfusion (ACP) on total aortic arch replacement. METHODS: From 2010 to 2013, data were collected from 99 consecutive patients with acute type A aortic dissection. All patients underwent total arch replacement plus frozen elephant trunk procedure. There were 51 patients in the deep hypothermia circulatory arrest (DHCA) group and 47 in the moderate hypothermia circulatory arrest (MHCA) group. Either unilateral or bilateral ACP was applied for cerebral protection. Perioperative data and measured outcomes were compared. RESULTS: Overall mean circulatory arrest time was 29.9 ± 6.0 minutes. Temporary neurologic dysfunction incidence was lower in the MHCA group compared with the DHCA group (21.3 vs. 40.4%, p = 0.041). The total 30-day mortality was 17.2% (14.9 vs. 19.2%, p = 0.568) and permanent neurologic dysfunction morbidity was 3.0% overall. In MHCA, less blood products were used than in DHCA. Moderate hypothermia was a protective factor for the composite outcome of temporary and permanent neurologic dysfunctions (odds ratio = 0.385; 95% confidence interval = 0.162-0.919). Hypothermic level did not significantly affect the perioperative alanine aminotransferase and serum creatinine levels. CONCLUSION: Within a short circulatory arrest time, MHCA combined with ACP seemed to be a safe and effective method to protect cerebral and visceral organs during total aortic arch replacement.

A Modified Wrapping-internal Shunt Method for Hemostasis in Bentall Procedure.

INTRODUCTION: Blindly punching between aorta and right atrium is dangerous. In that case, there is concerned about leakage between the two referred isolate parts. Besides, as the routine imaging techniques (echocardiography or computer tomography) are incompetent to detect this particular anatomic structure preoperatively, the intraoperative inspection appears necessary. Our method is useful for identifying this innate fusion plane. CASE REPORT: The thrombosis surrounding prosthesis was detected in the first ultrasound examination after the operation, which was considered to be an indication of successful hemostasis. As the innate fusion between aorta and right atrium appears no rare, the selective creation of left-to-right internal shunt is a valuable maneuver for controlling bleeding in appropriate cases.

Orthogonal analysis of variants in APOE gene using in-silico approaches reveals novel disrupting variants.

Introduction: Alzheimer's disease (AD) is one of the most prominent medical conditions in the world. Understanding the genetic component of the disease can greatly advance our knowledge regarding its progression, treatment and prognosis. Single amino-acid variants (SAVs) in the APOE gene have been widely investigated as a risk factor for AD Studies, including genome-wide association studies, meta-analysis based studies, and in-vivo animal studies, were carried out to investigate the functional importance and pathogenesis potential of APOE SAVs. However, given the high cost of such large-scale or experimental studies, there are only a handful of variants being reported that have definite explanations. The recent development of in-silico analytical approaches, especially large-scale deep learning models, has opened new opportunities for us to probe the structural and functional importance of APOE variants extensively. Method: In this study, we are taking an ensemble approach that simultaneously uses large-scale protein sequence-based models, including Evolutionary Scale Model and AlphaFold, together with a few in-silico functional prediction web services to investigate the known and possibly disease-causing SAVs in APOE and evaluate their likelihood of being functional and structurally disruptive. Results: As a result, using an ensemble approach with little to no prior field-specific knowledge, we reported 5 SAVs in APOE gene to be potentially disruptive, one of which (C112R) was classificed by previous studies as a key risk factor for AD. Discussion: Our study provided a novel framework to analyze and prioritize the functional and structural importance of SAVs for future experimental and functional validation.

Branching externalized guidewire to facilitate retrograde endograft deployment in the hybrid aortic repair with aortic valve replacement.

Background: The hybrid aortic repair consisting of root replacement and endovascular arch repair is an optimal alternative for patients unfit for circulatory arrest. However, an artificial aortic valve prosthesis might impede the endovascular procedure. This study aims to present our experience with the branching retrograde externalized guidewire (BREG) technique in such situations, and discuss its utility and efficiency. Methods: From January 2015 to June 2021, a total of 112 patients underwent aortic root/valve replacement combined with aortic arch repair. Among them, the BREG technique was adopted on 24 patients, and the traditional frozen elephant trunk (FET) technique was used for 88 patients. The indication of the BREG was as follows: high-risk patients not suitable for traditional open surgery; meanwhile, the aortic disease required extended repair, and the aortic valve needed to be replaced concomitantly. The data of the 2 groups were compared. Results: The cardiopulmonary bypass time (213.5 ± 73.6 min vs. 246.5 ± 46.2 min, P = 0.046) and cross-clamped time (109.0 ± 27.6 min vs. 139.0 ± 24.6 min, P < 0.001) were significantly shorter in the BREG group than that in the FET group. Less operative red blood cell consumption was achieved in the BREG group (6.6 ± 5.7 vs. 9.4 ± 8.0 U, P = 0.046). The 30-day mortality was similar between the 2 groups (8.3% BREG vs. 9.1% FET, P > 0.999). Conclusion: The BREG technique facilitated the advancement of endovascular stent graft, avoided impeding the aortic valve prosthesis in hybrid aortic surgery with aortic valve replacement, and may benefit high-risk patients.

The elevated admission white blood cell count relates to adverse surgical outcome of acute Stanford type a aortic dissection.

BACKGROUND: The purpose of the study was to examine the association between white blood cell count (WBCc) on admission and early outcome in patients with the acute Stanford type A aortic dissection (TAAD). METHODS: From January 2012 to December 2018, we retrospectively evaluated a series of 331 consecutive patients underwent surgery for TAAD in Tongji Hospital. The patients were divided into 2 groups based on the WBCc, i.e. the normal WBCc group (WBCc≤11 × 109/L) and leukocytosis group (WBCc> 11 × 109/L). The perioperative data were compared between the 2 groups. The in-hospital mortality and the compositive adverse event including multi-organ dysfunction syndrome, postoperative stroke, tracheotomy, and re-exploration for stopping bleeding were set as end points. Cox regression were used to assess the potential risk factors. RESULTS: The in-hospital mortality was nearly 3 time higher in the leukocytosis group than in the normal WBCc group (20.9% vs.8.1%, P = 0.001), and 15.1% overall. For the circulatory arrest, there was significant higher mortality in patients with leukocytosis than normal WBCc group (26.1%vs.8.9%, P = 0.001). After adjustment for confounding factors, the leukocytosis was found to be a strong independent predictor of in-hospital mortality (odds ratio = 3.10; 95% confidence interval 1.38 to 6.97, P = 0.006). The leukocytosis was also a risk factor of adverse events (odds ratio = 1.80; 95% confidence interval 1.07 to 3.04, P = 0.027). CONCLUSIONS: The WBCc within 24 h of admission for TAAD is a strong and independent predictor of in-hospital mortality as well as short-term clinical events. The results of this study have important clinical implications for risk-stratifying patients with TAAD.

A Simplified Continuous Two-stitch Suture for Bronchial Anastomosis of Left Single Lung Transplant in Dogs.

Large animal models are essential to pre-clinical trials of pulmonary transplantation and bronchial anastomosis poses a great technical challenge to the procedure. Presented here is a simplified continuous two-stitch suture technique into bronchial anastomosis during the course of left single lung transplantation in canine. Animals were divided into three groups with each group having 6 animals. Left single lung transplantation in canine was performed to assess the feasibility of using this technique for bronchial anastomosis. In the control groups, all anastomoses were done by using traditional technique. Allograft functions and hemodynamic parameters were monitored during a 3-h reperfusion period. Quality of bronchial healing and airway complications were assessed by bronchoscopic surveillance after transplantation. We successfully completed left lung transplantation in 18 dogs, and all the dogs survived the procedures. The new technique substantially simplified the procedures for bronchial anastomosis and greatly reduced the time for bronchial anastomosis (P<<0.01) and the ischemic time of the grafts (P<0.05) compared to the control group. The continuous two-stitch suture attenuated the tissue injury to allografts and led to better blood gas exchange function as compared to the control group (P<0.05). Good bronchial healing (Grade I) was observed in all the groups. A canine left single lung transplantation model is feasible by using the novel suture technique, and the new technique is as safe as the traditional method. The technique is easy to learn, particularly for less experienced operators. Simpler and time-saving, the technique has great potential to be widely employed in clinical lung transplantation.

Acute Type I aortic dissection: a propensity-matched comparison of elephant trunk and arch debranching repairs.

OBJECTIVES: Our goal was to compare the performance of the frozen elephant trunk (FET) and the hybrid aortic arch debranching procedures for acute Type I aortic dissection. METHODS: From January 2013 to December 2015, 168 patients with Type I aortic disease underwent ascending aorta and total aortic arch replacement with FET implantation (the FET group, n = 132) or arch debranching with 1-stage aortic arch exclusion using an endovascular stent in a retrograde manner (the debranching group, n = 36). A propensity score-matched subgroup of 26 pairs was identified. Perioperative data and mid-term follow-up results were assessed. RESULTS: In the FET and the debranching groups, the 30-day mortality rates were 14.4% and 5.6% (P = 0.254) and the incidence of stroke was 5.3% and 5.6% (P > 0.999). Cardiopulmonary bypass time was significantly shortened, and the circulatory arrest was exempted in the debranching group. Cardiopulmonary bypass time was identified as a predictor for 30-day mortality (P = 0.027, odds ratio 1.01). Body mass index ≥ 25 kg/m2 was associated with multiorgan dysfunction syndrome (P = 0.016, odds ratio 3.51). Surgical modality did not significantly affect early outcomes. The 3-year survival rate was 76.1% (95% confidence interval, 63.0-81.9%) in the FET group and 82.5% (95% confidence interval, 65.2-91.8%) in the debranching group (P = 0.330). CONCLUSIONS: The hybrid aortic arch procedure without circulatory arrest can be safely performed on patients with acute Type I aortic dissection. Irrespective of cost-effectiveness, arch debranching was a promising alternative for patients who were unfit for the FET procedure.

Next-generation sequencing identifies novel mutations in the FBN1 gene for two Chinese families with Marfan syndrome.

Marfan syndrome (MFS) is an autosomal dominant heterogeneous disorder of connective tissue characterized by the early development of thoracic aneurysms/dissections, together with defects of the ocular and skeletal systems. Loss-of-function mutations in fibrillin-1 (FBN1) encoded by the gene, FBN1 (MFS­1), and in the transforming growth factor ß receptor 2 (TGFBR2) gene, TGFBR2 (MFS­2), are major causes of this disorder. In the present study, a rapid and cost­effective method for genetically diagnosing MFS was described and used to identify disease­causing mutations in two unrelated pedigrees with MFS in mainland China. Using targeted semiconductor sequencing, two pathogenic mutations in four MFS patients of the two pedigrees were identified, including a novel frameshift insertion, p.G2120fsX2160, and a reported nonsense mutation, p.Arg529X (rs137854476), in the FBN1 gene. In addition, a rare, probably benign Chinese­specific polymorphism in the FBN1 gene was also revealed.

A simplified two-stitch sleeve technique for arterial anastomosis of cervical heterotopic cardiac transplantation in mice.

Although cervical cardiac transplantation is a well recognized useful model in diverse experimental settings, its widespread use, however, has been significantly hampered by the technical challenges relevant to small vessel anastomosis. We herein introduced a simplified two-stitch sleeve technique into arterial anastomosis during the course of cervical cardiac transplantation in mice. Cervical transplantation of allogenic and syngeneic cardiac grafts was conducted to assess the feasibility of this two-stitch sleeve technique in arterial anastomosis. Venous anastomosis was completed by the one-suture end-to-end microsuture technique, while arterial anastomosis was conducted by invaginating the recipient right common carotid artery into the graft left common carotid artery along with two guiding stitches. The two-stitch sleeve technique significantly simplified the procedures for arterial anastomosis as compared with that of the traditional microsuture technique (5.5 ± 1.8 min vs. 15.7 ± 3.0 min). However, the survival time for allografts (8.0 ± 0.2 day vs. 8.0 ± 0.4 day) and the long-term patency for syngeneic grafts (> 120 days) were the same as the grafts implanted by the traditional microsuture technique. This simplified sleeve technique is easy to learn, particularly for beginners without microsuture experience, and therefore, it has the great potential for widespread use in transplant immunology.