Hypoxia-Induced Piglet Model of Cardiac Arrest with Assisted Resuscitation by Extracorporeal Membrane Oxygenation.

The mortality rate of newborns with severe congenital heart disease (CHD) has significantly decreased over the past few decades. However, many of these children experience neurological impairments, particularly following a hypoxic cardiac arrest. The use of extracorporeal membrane oxygenation (ECMO) has been considered an effective treatment for severe hypoxia in CHD cases. Various clinical studies have examined the use of ECMO for resuscitation after hypoxic cardiac arrest, but the results have been contradictory, showing a significant incidence of both mortality and morbidity in some studies while others report good outcome. In order to investigate the mechanisms behind brain injury associated with extracorporeal circulation, we have developed a neonatal porcine model of hypoxia-induced cardiac arrest followed by veno-arterial ECMO therapy.

Unilateral Lung Removal in Combination with Monocrotaline or SU5416 in Rodents: A Reliable Model to Mimic the Pathology of the Human Pulmonary Hypertension.

Pulmonary hypertension (PH) is a chronic and progressive disorder characterized by elevated mean pulmonary arterial pressure, pulmonary vascular remodeling, and the development of concentric laminar intimal fibrosis with plexiform lesions. While rodent models have been developed to study PH, they have certain deficiencies and do not entirely replicate the human disease due to the heterogeneity of PH pathology. Therefore, combined models are necessary to study PH. Recent studies have shown that altered pulmonary blood flow is a significant trigger in the development of vascular remodeling and neointimal lesions. One of the most promising rodent models for increased pulmonary flow is the combination of unilateral left pneumonectomy with a "second hit" of monocrotaline (MCT) or SU5416. The removal of one lung in this model forces blood to circulate only in the other lung and induces increased and turbulent pulmonary blood flow. This increased vascular flow leads to progressive remodeling and occlusion of small pulmonary arteries. The second hit by MCT or SU5416 leads to endothelial cell dysfunction, resulting in severe PH and the development of plexiform arteriopathy.

Effects of Hormone Replacement Therapy on Women's Lung Health and Disease.

This review provides an overview of menopausal hormone therapy and pulmonary disease risk, with a focus on the effect of hormone replacement therapy (HRT) on pulmonary function and its relation to lung diseases. This summary is based on authors' knowledge in the field of HRT and supplemented by a PubMed search using the terms "menopause hormone therapy," "asthma", "lung cancer", "chronic obstructive pulmonary disease", "lung function", and "pulmonary hypertension". Available evidence indicates that there is limited research on the role of sex hormones in the susceptibility, severity, and progression of chronic respiratory diseases. However, some studies suggest that the hormonal changes that occur during the menopausal transition may have an impact on pulmonary function and respiratory diseases. Women are in need of convenient access to a safe and effective modality for personalized HRT based on an artificial intelligence (AI)-driven platform that will enable them to receive personalized hormonal treatment through frequent, convenient, and accurate measurements of hormone levels in peripheral blood.

Chronic thoracic pain after cardiac surgery: role of inflammation and biomechanical sternal stability.

Introduction: The pathogenesis of chronic chest pain after cardiac surgery has not been determinate. If left untreated, postoperative sternal pain reduces the quality of life and patient satisfaction with cardiac surgery. The purpose of the study was to examine the effect of chest inflammation on postoperative pain, risk factors for chronic pain after cardiac surgery and to explore how chest reconstruction was associated with the intensity of pain. Methods: The authors performed a study of acute and chronic thoracic pain after cardiac surgery in patients with and without sternal infection and compared different techniques for chest reconstruction. 42 high-risk patients for the development of mediastinitis were included. Patients with mediastinitis received chest reconstruction (group 1). Their demographics and risk factors were matched with no-infection patients with chest reconstruction (group 2) and subjects who underwent conventional sternal closure (group 3). Chronic pain was assessed by the numeric rating scale after surgery. Results: The assessment of the incidence and intensity of chest pain at 3 months post-surgery demonstrated that 14 out of 42 patients across all groups still experienced chronic pain. Specifically, in group 1 with sternal infection five patients had mild pain, while one patient experienced mild pain in group 2, and eight patients in group 3. Also, follow-up results indicated that the highest pain score was in group 3. While baseline levels of cytokines were increased among patients with sternal infection, at discharge only the level of interleukin 6 remained high compared to no infection groups. Compared to conventional closure, after chest reconstruction, we found better healing scores at 3-month follow-up and a higher percentage of patients with the complete sternal union. Conclusions: Overall, 14 out of 42 patients have chronic pain after cardiac surgery. The intensity of the pain in mediastinitis patients significantly decreased at 3 months follow-up after chest reconstruction. Thus, post-surgery mediastinitis is not a determining factor for development the chronic chest pain. There is no correlation between cytokines levels and pain score except interleukin 6 which remains elevated for a long time after treatment. Correlation between sternal healing score and chronic chest pain was demonstrated.

Acid ceramidase gene therapy ameliorates pulmonary arterial hypertension with right heart dysfunction.

BACKGROUND: Up-regulation of ceramides in pulmonary hypertension (PH), contributing to perturbations in sphingolipid homeostasis and the transition of cells to a senescence state. We assessed the safety, feasibility, and efficiency of acid ceramidase gene transfer in a rodent PH model. METHODS: A model of PH was established by the combination of left pneumonectomy and injection of Sugen toxin. Magnetic resonance imaging and right heart catheterization confirmed development of PH. Animals were subjected to intratracheal administration of synthetic adeno-associated viral vector (Anc80L65) carrying the acid ceramidase (Anc80L65.AC), an empty capsid vector, or saline. Therapeutic efficacy was evaluated 8 weeks after gene delivery. RESULTS: Hemodynamic assessment 4 weeks after PH model the development demonstrated an increase in the mean pulmonary artery pressure to 30.4 ± 2.13 mmHg versus 10.4 ± 1.65 mmHg in sham (p < 0.001), which was consistent with the definition of PH. We documented a significant increase in pulmonary vascular resistance in the saline-treated (6.79 ± 0.85 mm Hg) and empty capsid (6.94 ± 0.47 mm Hg) groups, but not in animals receiving Anc80L65.AC (4.44 ± 0.71 mm Hg, p < 0.001). Morphometric analysis demonstrated an increase in medial wall thickness in control groups in comparison to those treated with acid ceramidase. After acid ceramidase gene delivery, a significant decrease of pro-inflammatory factors, interleukins, and senescence markers was observed. CONCLUSION: Gene delivery of acid ceramidase provided tropism to pulmonary tissue and ameliorated vascular remodeling with right ventricular dysfunction in pulmonary hypertension.

Cardiac Targeted Adeno-Associated Virus Injection in Rats.

Gene therapy is a promising approach in the treatment of cardiovascular diseases. The vectors available for cardiovascular gene therapy have significantly improved over time. Cardiac tropism is a primary characteristic of an ideal vector along with a long-term expression profile and a minimal risk of cellular immune response. Preclinical and clinical studies have demonstrated that adeno-associated viral (AAV) vectors are one of the most attractive vehicles for gene transfer. AAV has gained great popularity in the last years because of its biological properties and advantages over other viral vector systems. In this chapter we will describe methods for intracardiac delivery of AAV vector in rats.

Surgical Methods for Cardiac Gene Delivery in Large Animals.

This chapter describes main strategies of surgical gene delivery in large animals. Existing methods of cardiac gene transfer can be classified by the site of injection, interventional approach, and type of cardiac circulation at the time of transfer. Randomized clinical trials have suggested that the therapeutic benefits of gene therapy are not as substantial as expected from animal studies. This discordance in results is largely due to gene delivery methods that may be effective in small animals but are not scalable to larger species and, therefore, cannot transduce a sufficient fraction of myocytes to establish long-term clinical efficacy. Ideally, an optimized gene transfer should incorporate the following: a closed-loop recirculation for extended transgene residence time; vector washout form the vascular system after transfer to prevent collateral expression; use of methods to increase myocardial transcapillary gradient for viral particles for a better transduction, probably retrograde route of gene delivery through the coronary venous system; and myocardial ischemic preconditioning.

Efficient cardiac gene transfer and early-onset expression of a synthetic adeno-associated viral vector, Anc80L65, after intramyocardial administration.

OBJECTIVE: Gene therapy is a promising approach in the treatment of cardiovascular diseases. Preclinical and clinical studies have demonstrated that adeno-associated viral vectors are the most attractive vehicles for gene transfer. However, preexisting immunity, delayed gene expression, and postinfection immune response limit the success of this technology. The aim of this study was to investigate the efficacy of the first synthetic adeno-associated viral lineage clone, Anc80L65, for cardiac gene therapy. METHODS: By combining 2 different reporter approaches by fluorescence with green fluorescent protein and bioluminescence (Firefly luciferase), we compared transduction efficiency of Anc80L65 and adeno-associated virus, serotype 9 in neonatal rat cardiomyocytes ex vivo and rat hearts in vivo after intramyocardial and intracoronary administration. RESULTS: In cardiomyocytes, Anc80L65 provided a green fluorescent protein expression of 28.9% (36.4 ± 3.34 cells/field) at 24 hours and approximately 100% on day 7. In contrast, adeno-associated virus, serotype 9 green fluorescent protein provided minimal green fluorescent protein expression of 5.64% at 24 hours and 11.8% on day 7. After intramyocardial injection, vector expression peaked on day 7 with Anc80L65; however, with adeno-associated virus, serotype 9 the peak expression was during week 6. Administration of Anc80L65 demonstrated significantly more efficient expression of reporter gene than after adeno-associated virus, serotype 9 at 6 weeks (6.81 ± 0.64 log10 gc/100 ng DNA vs 6.49 ± 0.28 log10 gc/100 ng DNA, P < .05). These results were consistent with the amount of genome copy per cell observed in the heart. CONCLUSIONS: Anc80L65 vector allows fast and robust gene transduction compared with adeno-associated virus, serotype 9 vector in cardiac gene therapy. Anc80L65 did not adversely affect cardiac function and caused no inflammatory response or toxicity.

Right predominant electrical remodeling in a pure model of pulmonary hypertension promotes reentrant arrhythmias.

BACKGROUND: Electrophysiological (EP) properties have been studied mainly in the monocrotaline model of pulmonary arterial hypertension (PAH). Findings are confounded by major extrapulmonary toxicities, which preclude the ability to draw definitive conclusions regarding the role of PAH per se in EP remodeling. OBJECTIVE: The purpose of this study was to investigate the EP substrate and arrhythmic vulnerability of a new model of PAH that avoids extracardiopulmonary toxicities. METHODS: Sprague-Dawley rats underwent left pneumonectomy (Pn) followed by injection of the vascular endothelial growth factor inhibitor Sugen-5416 (Su/Pn). Five weeks later, cardiac magnetic resonance imaging was performed in vivo, optical action potential (AP) mapping ex vivo, and molecular analyses in vitro. RESULTS: Su/Pn rats exhibited right ventricular (RV) hypertrophy and were highly prone to pacing-induced ventricular tachycardia/fibrillation (VT/VF). Underlying this susceptibility was disproportionate RV-sided prolongation of AP duration, which promoted formation of right-sided AP alternans at physiological rates. While propagation was impaired at all rates in Su/Pn rats, the extent of conduction slowing was most severe immediately before the emergence of interventricular lines of block and onset of VT/VF. Measurement of the cardiac wavelength revealed a decrease in Su/Pn relative to control. Nav1.5 and total connexin 43 expression was not altered, while connexin 43 phosphorylation was decreased in PAH. Col1a1 and Col3a1 transcripts were upregulated coinciding with myocardial fibrosis. Once generated, VT/VF was sustained by multiple reentrant circuits with a lower frequency of RV activation due to wavebreak formation. CONCLUSION: In this pure model of PAH, we document RV-predominant remodeling that promotes multiwavelet reentry underlying VT. The Su/Pn model represents a severe form of PAH that allows the study of EP properties without the confounding influence of extrapulmonary toxicity.

Combination Therapy with STAT3 Inhibitor Enhances SERCA2a-Induced BMPR2 Expression and Inhibits Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a devastating lung disease characterized by the progressive obstruction of the distal pulmonary arteries (PA). Structural and functional alteration of pulmonary artery smooth muscle cells (PASMC) and endothelial cells (PAEC) contributes to PA wall remodeling and vascular resistance, which may lead to maladaptive right ventricular (RV) failure and, ultimately, death. Here, we found that decreased expression of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a (SERCA2a) in the lung samples of PAH patients was associated with the down-regulation of bone morphogenetic protein receptor type 2 (BMPR2) and the activation of signal transducer and activator of transcription 3 (STAT3). Our results showed that the antiproliferative properties of SERCA2a are mediated through the STAT3/BMPR2 pathway. At the molecular level, transcriptome analysis of PASMCs co-overexpressing SERCA2a and BMPR2 identified STAT3 amongst the most highly regulated transcription factors. Using a specific siRNA and a potent pharmacological STAT3 inhibitor (STAT3i, HJC0152), we found that SERCA2a potentiated BMPR2 expression by repressing STAT3 activity in PASMCs and PAECs. In vivo, we used a validated and efficient model of severe PAH induced by unilateral left pneumonectomy combined with monocrotaline (PNT/MCT) to further evaluate the therapeutic potential of single and combination therapies using adeno-associated virus (AAV) technology and a STAT3i. We found that intratracheal delivery of AAV1 encoding SERCA2 or BMPR2 alone or STAT3i was sufficient to reduce the mean PA pressure and vascular remodeling while improving RV systolic pressures, RV ejection fraction, and cardiac remodeling. Interestingly, we found that combined therapy of AAV1.hSERCA2a with AAV1.hBMPR2 or STAT3i enhanced the beneficial effects of SERCA2a. Finally, we used cardiac magnetic resonance imaging to measure RV function and found that therapies using AAV1.hSERCA2a alone or combined with STAT3i significantly inhibited RV structural and functional changes in PNT/MCT-induced PAH. In conclusion, our study demonstrated that combination therapies using SERCA2a gene transfer with a STAT3 inhibitor could represent a new promising therapeutic alternative to inhibit PAH and to restore BMPR2 expression by limiting STAT3 activity.

Inflammatory Responses with Left Ventricular Compromise after Induction of Myocardial Infarcts in Sheep (Ovis aries).

Ischemic myocardial disease is a major cause of death among humans worldwide; it results in scarring and pallor of the myocardium and triggers an inflammatory response that contributes to impaired left ventricular function. This response includes and is evidenced by the production of several inflammatory cytokines including TNFα, IL1ß, IL4, IFNγ, IL10 and IL6. In the current study, myocardial infarcts were induced in 6 mo old male castrated sheep by ligation of the left circumflex obtuse marginal arteries (OM 1 and 2). MRI was used to measure parameters of left ventricular function that include EDV, ESV, EF, SVI, dp/dt max and dp/dt min at baseline and at 4 wk and 3 mo after infarct induction. We also measured serum concentrations of an array of cytokines. Postmortem histologic findings corroborate the existence of left ventricular myocardial injury and deterioration. Our data show a correlation between serum cytokine concentrations and the development of myocardial damage and left ventricular functional compromise.

Use of longitudinal rigid sternal fixation in prevention and treatment of wound complications among high-risk patients after cardiac surgery.

BACKGROUND: Traditionally, wire cerclage closure has been used to reapproximate the sternum after cardiac surgery. Recent evidence suggests that rigid sternal fixation may reduce the risk of wound complications. The aim of this study was to analyze our 10-year experience with longitudinal rigid sternal fixation (LRSF) for prevention and treatment of wound complications in high-risk patients. METHODS: We reviewed data from cardiac surgical database of patients who underwent LRSF, and compared their outcomes with conventional wire cerclage closure (CWS). Among these 319 patients were designated as having high-risk for the development of deep wound complications and received primary LRSF (treatment group). We matched their outcomes with 319 patients who met indications for LRSF however, underwent standard closure with CWC (control group). RESULTS: Both groups were comparable regarding preoperative and intraoperative variables. The benefit observed among matched patients who had undergone LRSF was largely driven by a decreased rate of deep wound infections (0.63% vs. 3.45% vs., p < .01), 30-day mortality (1.57% vs. 5.96%) and hospital length (8.2 vs. 11.7 days) p < .05, respectively. A multivariate logistic regression analysis found four independent risk factors for the development of sternal dehiscence. Sternal healing evaluated by computerized tomography scan using 6-point scale at 3 months after surgery was superior in LRSF patients. Pain scores were significantly lower in LRSF patients as well. CONCLUSIONS: In patients with an increased risk for sternal instability and wound infections after cardiac surgery, sternal reconstruction using LRSF is an effective technique to stabilize sternum for preventive and treatment purposes.

Advantages of intraoperative implantation of Impella 5.5 SmartAssist in the Management of Acute Post-Infarction Ventricular Septal Defect with cardiogenic shock.

BACKGROUND: Despite advances in surgical techniques and aggressive therapy of post-infarction ventricular septal defect (VSD) with cardiogenic shock, the overall morbidity and mortality is frustratingly high. The Impella 5.5 SmartAssist (Abiomed, Danvers, MA) is a surgically implanted temporary device, recently approved by the FDA ( https://www.businesswire.com/news/home/20190925005454/en/ ) for treatment of patients in cardiogenic shock, and may fill a technological gap for patients who require acute circulatory support after VSD closure. CASE PRESENTATION: We report our initial experience for two patients with post myocardial infarction VSD in the setting of cardiogenic shock supported with trans-aortic implantation Impella 5.5 SmartAssist. First patient had a posterior VSD with a left to right shunt (Qp/Qs ratio of 3.3), blood pressure 80/35 mmHg, right ventricle dysfunction, severe pulmonary arterial hypertension (an estimated systolic pulmonary artery pressure of 45 mmHg), and severe mitral valve regurgitation. Second patient was admitted for massive MI with large anterior VSD (Qp/Qs ratio of 2.8). Under cardiopulmonary bypass with cardioplegic arrest both patients underwent urgent VSD closure with trans-aortic implantation of the Impella. Minimal postoperative support was required. Patients were discharged on postoperative day 10 and 14 and remained well 3 months later. Follow-up echocardiogram showed no residual shunt. CONCLUSIONS: Early surgical implantation of Impella 5.5 SmartAssist can prevent multiorgan dysfunction and stabilize the patients in cardiogenic shock with post-myocardial infarction VSD.

Median Sternotomy After Sternal Reconstruction With Bilateral Longitudinal Plating in a Patient With Osteoporosis.

In recent decades, new information has arisen regarding sternal healing and extended indications for using rigid plate fixation in patients during cardio-thoracic procedures. Three randomized controlled multicenter clinical trials recently demonstrated positive results after rigid plate fixation, including reduced sternal complications and decreased length of hospital stay. However, redo-sternotomy after sternal reconstruction utilizing rigid fixation has not been previously delineated in surgical literature. This case highlights the technical challenges of performing a median sternotomy for cardiac surgery after sternal reconstruction with bilateral longitudinal plating.

Successful Transduction with AAV Vectors after Selective Depletion of Anti-AAV Antibodies by Immunoadsorption.

Gene therapy with adeno-associated virus (AAV)-based vectors shows great promise for the gene therapeutic treatment of a broad array of diseases. In fact, the treatment of genetic diseases with AAV vectors is currently the only in vivo gene therapy approach that is approved by the US Food and Drug Administration (FDA). Unfortunately, pre-existing antibodies against AAV severely limit the patient population that can potentially benefit from AAV gene therapy, especially if the vector is delivered by intravenous injection. Here, we demonstrate that we can selectively deplete anti-AAV antibodies by hemapheresis combined with AAV9 particles coupled to Sepharose beads. In rats that underwent hemapheresis and immunoadsorption, luciferase expression was dramatically increased in the hearts and fully restored in the livers of these rats. Importantly, our method can be readily adapted for the use in clinical AAV gene therapy.