Impact of the coronavirus disease 2019 (COVID-19) pandemic on the care of patients with acute and chronic aortic conditions.

OBJECTIVES: To evaluate the impact of the coronavirus disease 2019 (COVID-19) pandemic on acute and elective thoracic and abdominal aortic procedures. METHODS: Forty departments shared their data on acute and elective thoracic and abdominal aortic procedures between January and May 2020 and January and May 2019 in Europe, Asia and the USA. Admission rates as well as delay from onset of symptoms to referral were compared. RESULTS: No differences in the number of acute thoracic and abdominal aortic procedures were observed between 2020 and the reference period in 2019 [incidence rates ratio (IRR): 0.96, confidence interval (CI) 0.89-1.04; P = 0.39]. Also, no difference in the time interval from acute onset of symptoms to referral was recorded (<12 h 32% vs > 12 h 68% in 2020, < 12 h 34% vs > 12 h 66% in 2019 P = 0.29). Conversely, a decline of 35% in elective procedures was seen (IRR: 0.81, CI 0.76-0.87; P < 0.001) with substantial differences between countries and the most pronounced decline in Italy (-40%, P < 0.001). Interestingly, in Switzerland, an increase in the number of elective cases was observed (+35%, P = 0.02). CONCLUSIONS: There was no change in the number of acute thoracic and abdominal aortic cases and procedures during the initial wave of the COVID-19 pandemic, whereas the case load of elective operations and procedures decreased significantly. Patients with acute aortic syndromes presented despite COVID-19 and were managed according to current guidelines. Further analysis is required to prove that deferral of elective cases had no impact on premature mortality.

Everolimus attenuates neointimal hyperplasia in cultured human saphenous vein grafts.

OBJECTIVE: Neointimal hyperplasia is the first step in a cascade leading to a reduced patency rate of saphenous vein grafts in comparison to arterial grafts in coronary artery bypass grafting. Using cultured human saphenous vein grafts as a model for coronary artery bypass grafting, we investigated if the mammalian target of rapamycin inhibitor everolimus attenuates neointimal hyperplasia. METHODS: Saphenous vein grafts from 10 patients undergoing coronary artery bypass grafting were processed as follows: from each patient, one segment served as baseline control at day 0. Two segments were cultured in a neointimal hyperplasia model separately. One received no treatment and the other everolimus (1 microM). All vein grafts underwent histomorphometric analysis, assessment of proliferation by Ki-67 immunostaining and quantification of phospho-S6 ribosomal protein using western blot analysis. RESULTS: Everolimus treatment resulted in reduced neointimal hyperplasia (thickness 3.7+/-1.2 microm) compared to untreated controls (10.1+/-2.5 microm, p=0.008). The intima/intima+media-ratio was reduced in the everolimus group (0.10+/-0.02) compared to untreated controls (0.24+/-0.07, p=0.008). The number of Ki-67 positive proliferating cells in everolimus treated vein grafts (15+/-7 cells/high power field) showed a tendency of reduction compared to untreated controls (36+/-20 cells/high power field, p=0.036). Finally, everolimus treatment resulted in downregulation of S6 ribosomal protein phosphorylation in comparison to untreated controls. CONCLUSION: Everolimus is able to reduce neointimal proliferation in cultured human saphenous vein grafts by inhibition of the mammalian target of rapamycin, even though different transfection methods are to be evaluated for a clinical application in coronary artery bypass grafting.

PICOT is a critical regulator of cardiac hypertrophy and cardiomyocyte contractility.

PICOT (PKC-interacting cousin of thioredoxin) was previously shown to inhibit the development of cardiac hypertrophy, concomitant with an increase in cardiomyocyte contractility. To explore the physiological function of PICOT in the hearts, we generated a PICOT-deficient mouse line by using a gene trap approach. PICOT(-/-) mice were embryonic lethal indicating that PICOT plays an essential role during embryogenesis, whereas PICOT(+/-) mice were viable with no apparent morphological defects. The PICOT protein levels were reduced by about 50% in the hearts of PICOT(+/-) mice. Significantly exacerbated cardiac hypertrophy was induced by pressure overload in PICOT(+/-) mice relative to that seen in wild type littermates. In line with this observation, calcineurin-NFAT signaling was greatly enhanced by pressure overload in the hearts of PICOT(+/-) mice. Cardiomyocytes from PICOT(+/-) mice exhibited significantly reduced contractility, which may be due in part to hypophosphorylation of phospholamban and reduced SERCA activity. These data indicate that the precise PICOT protein level significantly affects the process of cardiac hypertrophy and cardiomyocyte contractility. We suggest that PICOT plays as a critical negative regulator of cardiac hypertrophy and a positive inotropic regulator.

PICOT inhibits cardiac hypertrophy and enhances ventricular function and cardiomyocyte contractility.

Multiple signaling pathways involving protein kinase C (PKC) have been implicated in the development of cardiac hypertrophy. We observed that a putative PKC inhibitor, PICOT (PKC-Interacting Cousin Of Thioredoxin) was upregulated in response to hypertrophic stimuli both in vitro and in vivo. This suggested that PICOT may act as an endogenous negative feedback regulator of cardiac hypertrophy through its ability to inhibit PKC activity, which is elevated during cardiac hypertrophy. Adenovirus-mediated gene transfer of PICOT completely blocked the hypertrophic response of neonatal rat cardiomyocytes to enthothelin-1 and phenylephrine, as demonstrated by cell size, sarcomere rearrangement, atrial natriuretic factor expression, and rates of protein synthesis. Transgenic mice with cardiac-specific overexpression of PICOT showed that PICOT is a potent inhibitor of cardiac hypertrophy induced by pressure overload. In addition, PICOT overexpression dramatically increased the ventricular function and cardiomyocyte contractility as measured by ejection fraction and end-systolic pressure of transgenic hearts and peak shortening of isolated cardiomyocytes, respectively. Intracellular Ca(2+) handing analysis revealed that increases in myofilament Ca(2+) responsiveness, together with increased rate of sarcoplasmic reticulum Ca(2+) reuptake, are associated with the enhanced contractility in PICOT-overexpressing cardiomyocytes. The inhibition of cardiac remodeling by of PICOT with a concomitant increase in ventricular function and cardiomyocyte contractility suggests that PICOT may provide an efficient modality for treatment of cardiac hypertrophy and heart failure.

S-nitroso human serum albumin attenuates ischemia/reperfusion injury after cardioplegic arrest in isolated rabbit hearts.

BACKGROUND: Depletion of nitric oxide (NO) is associated with ischemia/reperfusion injury. The novel NO donor, S-nitroso human serum albumin (S-NO-HSA), could bridge NO depletion during reperfusion in cardiac transplantation and minimize ischemia/reperfusion injury. METHODS: In an isolated erythrocyte-perfused working heart model, rabbit hearts were randomly assigned after assessment of hemodynamic baseline values to receive S-NO-HSA (0.2 micromol/100 ml, n = 8), L-arginine (10 mmol/100 ml, n = 8) or albumin (control) (0.2 micromol/100 ml, n = 8). After 20 minutes of infusion, the hearts were arrested and stored in Celsior (4 degrees C) enriched with respective drugs for 6 hours, followed by 75 minutes of reperfusion. Hemodynamic values were assessed and biopsy specimens were taken to determine calcium-ionophore stimulated release of NO and superoxide. RESULTS: During early reperfusion, recovery of cardiac output (75% +/- 6% vs 49% +/- 5%, p < 0.05) and coronary flow (99% +/- 8% vs 70% +/- 5%, p < 0.05) were higher, and myocardial oxygen consumption was reduced in the S-NO-HSA Group compared with Control (4.08 +/- 0.46 ml/min/0.1 kg vs 6.78 +/- 0.38 ml/min/0.1 kg, p < 0.01). At the end of the experiment cardiac output (53% +/- 5% vs 27% +/- 5%, p < 0.01) was higher and left atrial pressure (115% +/- 9% vs 150% +/- 8%, p < 0.05) was lower in the S-NO-HSA Group compared with Control. NO release was increased (1,040 +/- 50 nmol/liter and 1,070 +/- 60 nmol/liter vs 860 +/- 10 nmol/liter, p < 0.01) and superoxide release diminished (31 +/- 5 nmol/liter and 38 +/- 5 nmol/liter vs 64 +/- 5 nmol/liter, p < .01) in the S-NO-HSA and L-arginine Groups compared with Control. CONCLUSION: S-NO-HSA improved hemodynamic functions after prolonged hypothermic cardiac arrest by supplementing NO and thereby decreasing ischemia/reperfusion injury.

Increased leakage of sarcoplasmic reticulum Ca2+ contributes to abnormal myocyte Ca2+ handling and shortening in sepsis.

OBJECTIVE: Changes in cardiac function due to sepsis have been widely reported. However, the underlying mechanisms remain poorly understood. In the mammalian heart, myocyte function and intracellular calcium homeostasis are closely coupled. In this study we tested the hypothesis that alterations in cardiac calcium homeostasis due to sepsis underlie the observed myocyte dysfunction. DESIGN: Randomized prospective animal study. SETTING: Research laboratory. SUBJECTS: Male Sprague-Dawley rats weighing 250-275 g. INTERVENTIONS: We induced sepsis by cecal ligation and puncture in the rat, which mimics the type of infection caused by perforation of the intestine in humans. MEASUREMENTS AND RESULTS: Forty-eight hours after cecal ligation and puncture, isolated cardiac ventricular cardiomyocytes demonstrated a 57% decreased peak systolic [Ca]. The time constant of the Ca transient increased 71% and 57% in myocytes obtained 24 hrs and 48 hrs after cecal ligation and puncture, respectively. The average shortening of cardiomyocytes 48 hrs after cecal ligation and puncture was significantly decreased. To investigate the cellular mechanisms of altered Ca transients and myocyte shortening, we measured Ca sparks, the spontaneous local Ca release events in cardiomyocytes at resting states. The Ca spark frequency progressively increased in myocytes 24 hrs and 48 hrs after cecal ligation and puncture. The total activity of sparks also increased compared with sham-operated animals. The overall leakage of sarcoplasmic reticulum Ca in resting states was increased in sepsis and resulted in reduced sarcoplasmic reticulum Ca content. CONCLUSIONS: Abnormal Ca leakage from the sarcoplasmic reticulum contributes significantly to the depressed myocyte shortening in sepsis. In the future, modalities that prevent this Ca leakage may prove beneficial in the treatment of sepsis-induced myocyte shortening.

Cardiac-specific gene expression facilitated by an enhanced myosin light chain promoter.

BACKGROUND: Adenoviral gene transfer has been shown to be effective in cardiac myocytes in vitro and in vivo. A major limitation of myocardial gene therapy is the extracardiac transgene expression. METHODS: To minimize extracardiac gene expression, we have constructed a tissue-specific promoter for cardiac gene transfer, namely, the 250-bp fragment of the myosin light chain-2v (MLC-2v) gene, which is known to be expressed in a tissue-specific manner in ventricular myocardium followed by a luciferase (luc) reporter gene (Ad.4 x MLC250.Luc). Rat cardiomyocytes, liver and kidney cells were infected with Ad.4 x MLC.Luc or control vectors. For in vivo testing, Ad.4 x MLC250.Luc was injected into the myocardium or in the liver of rats. Kinetics of promoter activity were monitored over 8 days using a cooled CCD camera. RESULTS: In vitro: By infecting hepatic versus cardiomyocyte cells, we found that the promoter specificity ratio (luc activity in cardiomyocytes per liver cells) was 20.4 versus 0.9 (Ad.4 x MLC250.Luc vs. Ad.CMV). In vivo: Ad.4 x MLC250.Luc significantly reduced luc activity in liver (38.4-fold), lung (16.1-fold), and kidney (21.8-fold) versus Ad.CMV (p =.01); whereas activity in the heart was only 3.8-fold decreased. The gene expression rate of cardiomyocytes versus hepatocytes was 7:1 (Ad.4 x MLC.Luc) versus 1:1.4 (Ad.CMV.Luc). DISCUSSION: This new vector may be useful to validate therapeutic approaches in animal disease models and offers the perspective for selective expression of therapeutic genes in the diseased heart.

Apoptosis in heart failure and the senescent heart.

The progressive loss of cardiac myocytes by apoptotic cell death has been discussed as an important pathogenic component in the failing myocardium as well in the aging heart. The degree to which apoptosis contributes to myocyte loss in these conditions, however, is a controversial issue. This review focuses on the regulation of apoptosis, evidence implicating apoptosis as a mechanism for the progression and development of heart failure, the role of apoptotic death in senescent cardiac dysfunction, as well as on the problems of detection of apoptosis.

Gene therapy for the treatment of heart failure--calcium signaling.

The knowledge of molecular mechanisms indicated in cardiac dysfunction has increased dramatically over the last decade and yields considerable potential for new treatment options in heart failure. Alterations in intracellular calcium signaling play a crucial role in the pathophysiology of heart failure, and in recent years, somatic gene transfer has been identified as an important tool to help understand the relative contribution of specific calcium-handling proteins in heart failure. This article reviews recent advances in gene delivery techniques aimed at global myocardial transfection and discusses molecular therapeutic targets identified within intracellular calcium signaling pathways in heart failure.

Optimizing ischemia/reperfusion in the failing rat heart--improved myocardial protection with acute ACE inhibition.

BACKGROUND: Whereas the number of patients with reduced left ventricular function after myocardial infarction who need revascularization is increasing, the operative outcome is still inadequate. Consequently, drugs that increase myocardial perfusion and decrease oxygen consumption of the remodeled myocardium are of particular interest to cardiac surgeons. Angiotensin-converting enzyme inhibitors (ACE-I) provide this pharmacologic profile. This study tests the hypothesis whether acute ACE inhibition during cardioplegic arrest improves outcome in failing rat hearts. METHODS AND RESULTS: Male Wistar rats (260+/-15 g) underwent coronary ligation. Ten weeks later the rats had developed heart failure (HF). Hearts were harvested and studied on a red cell-perfused working heart: 60 minutes of ischemia, protected by cold blood cardioplegia (CP) every 20 minutes, and 45 minutes of reperfusion. Rats were randomly assigned to 2 groups, 1 group receiving the ACE-I quinaprilat with CP (QuinaMI, n=11), and 1 group receiving CP only (MI, n=8). Hemodynamic recovery, high-energy phosphates (HEP), and morphometry were analyzed. Groups showed similar degrees of myocardial infarction (44+/-5 versus 39+/-4% of LVmass), LVEDP (5.0+/-1 versus 4+/-1 mm Hg) and no differences in baseline values such as external heart work (EHW) and coronary flow (CF). At the end of reperfusion, EHW and CF were significantly higher in QuinaMI than MI (P<0.05 and 0.01), LVEDP had returned to baseline in QuinaMI (P<0.01). HEP were significantly higher preserved in QuinaMI than MI (P<0.05). CONCLUSIONS: Acute ACE inhibition during CP improves postischemic systolic and diastolic function, coronary perfusion as well as HEP-levels in a rat model of HF. These results may have clinical impact on patients with HF undergoing cardiac surgery.