Emmanuel Chorianopoulos

Anti-PlGF Inhibits Growth of VEGF(R)-Inhibitor-Resistant Tumors without Affecting Healthy Vessels

Novel antiangiogenic strategies with complementary mechanisms are needed to maximize efficacy and minimize resistance to current angiogenesis inhibitors. We explored the therapeutic potential and mechanisms of alphaPlGF, an antibody against placental growth factor (PlGF), a VEGF homolog, which regulates the angiogenic switch in disease, but not in health. alphaPlGF inhibited growth and metastasis of various tumors, including those resistant to VEGF(R) inhibitors (VEGF(R)Is), and enhanced the efficacy of chemotherapy and VEGF(R)Is. alphaPlGF inhibited angiogenesis, lymphangiogenesis, and tumor cell motility. Distinct from VEGF(R)Is, alphaPlGF prevented infiltration of angiogenic macrophages and severe tumor hypoxia, and thus, did not switch on the angiogenic rescue program responsible for resistance to VEGF(R)Is. Moreover, it did not cause or enhance VEGF(R)I-related side effects. The efficacy and safety of alphaPlGF, its pleiotropic and complementary mechanism to VEGF(R)Is, and the negligible induction of an angiogenic rescue program suggest that alphaPlGF may constitute a novel approach for cancer treatment.

Myocardial hypertrophy in the absence of external stimuli is induced by angiogenesis in mice.

Although studies have suggested a role for angiogenesis in determining heart size during conditions demanding enhanced cardiac performance, the role of EC mass in determining the normal organ size is poorly understood. To explore the relationship between cardiac vasculature and normal heart size, we generated a transgenic mouse with a regulatable expression of the secreted angiogenic growth factor PR39 in cardiomyocytes. A significant change in adult mouse EC mass was apparent by 3 weeks following PR39 induction. Heart weight; cardiomyocyte size; vascular density normalization; upregulation of hypertrophy markers including atrial natriuretic factor, beta-MHC, and GATA4; and activation of the Akt and MAP kinase pathways were observed at 6 weeks post-induction. Treatment of PR39-induced mice with the eNOS inhibitor L-NAME in the last 3 weeks of a 6-week stimulation period resulted in a significant suppression of heart growth and a reduction in hypertrophic marker expression. Injection of PR39 or another angiogenic growth factor, VEGF-B, into murine hearts during myocardial infarction led to induction of myocardial hypertrophy and restoration of myocardial function. Thus stimulation of vascular growth in normal adult mouse hearts leads to an increase in cardiac mass.

Increased expression of syndecan-1 protects against cardiac dilatation and dysfunction after myocardial infarction

Background— The cell-associated proteoglycan syndecan-1 (Synd1) closely regulates inflammation and cell-matrix interactions during wound healing and tumorigenesis. The present study investigated whether Synd1 may also regulate cardiac inflammation, matrix remodeling, and function after myocardial infarction (MI). Methods and Results— First, we showed increased protein and mRNA expression of Synd1 from 24 hours on, reaching its maximum at 7 days after MI and declining thereafter. Targeted deletion of Synd1 resulted in increased inflammation and accelerated, yet functionally adverse, infarct healing after MI. In concordance, adenoviral gene expression of Synd1 protected against exaggerated inflammation after MI, mainly by reducing transendothelial adhesion and migration of leukocytes, as shown in vitro. Increased inflammation in the absence of Synd1 resulted in increased monocyte chemoattractant protein-1 expression, increased activity of matrix metalloproteinase-2 and -9, and decreased activity of tissue transglutaminase, associated with increased collagen fragmentation and disorganization. Exaggerated inflammation and adverse matrix remodeling in the absence of Synd1 increased cardiac dilatation and impaired systolic function, whereas gene overexpression of Synd1 reduced inflammation and protected against cardiac dilatation and failure. Conclusions— Increased expression of Synd1 in the infarct protects against exaggerated inflammation and adverse infarct healing, thereby reducing cardiac dilatation and dysfunction after MI in mice.

Reevaluation of the Role of VEGF-B Suggests a Restricted Role in the Revascularization of the Ischemic Myocardium

Objective—The endogenous role of the VEGF family member vascular endothelial growth factor-B (VEGF-B) in pathological angiogenesis remains unclear. Methods and Results—We studied the role of VEGF-B in various models of pathological angiogenesis using mice lacking VEGF-B (VEGF-B−/−) or overexpressing VEGF-B167. After occlusion of the left coronary artery, VEGF-B deficiency impaired vessel growth in the ischemic myocardium whereas, in wild-type mice, VEGF-B167 overexpression enhanced revascularization of the infarct and ischemic border zone. By contrast, VEGF-B deficiency did not affect vessel growth in the wounded skin, hypoxic lung, ischemic retina, or ischemic limb. Moreover, VEGF-B167 overexpression failed to enhance vascular growth in the skin or ischemic limb. Conclusion—VEGF-B appears to have a relatively restricted angiogenic activity in the ischemic heart. These insights might offer novel therapeutic opportunities.

Technical Challenge of Transfemoral Aortic Valve Implantation in a Patient With Severe Aortic Regurgitation

Transfemoral aortic valve implantation (TAVI) has become an important interventional technique for patients with severe aortic stenosis (AS) and very high surgical risks. Several studies have demonstrated the feasibility and clinical success of TAVI procedures.1,2 Indications of transfemoral implantations of aortic valves are clearly defined, and TAVI should only be performed in patients with symptomatic severe aortic stenosis, high surgical risks (EuroScore ≥20%, or other severe concomitant disease that would prohibit surgery), aortic annulus diameter and peripheral vessel diameters within the required dimensions for Edwards SapienXT or Medtronic CoreValve devices and sheaths. However, several off-label applications have been described in recent years that could broaden the range of TAVI interventions, such as valve-in-valve implantations in degenerated aortic bioprostheses.3 One of the contraindications for TAVI is severe aortic regurgitation (AR). …

TNF-Like Weak Inducer of Apoptosis Aggravates Left Ventricular Dysfunction after Myocardial Infarction in Mice

Background. TNF-like weak inducer of apoptosis (TWEAK) has recently been shown to be potentially involved in adverse cardiac remodeling. However, neither the exact role of TWEAK itself nor of its receptor Fn14 in this setting is known. Aim of the Study. To analyze the effects of sTWEAK on myocardial function and gene expression in response to experimental myocardial infarction in mice. Results. TWEAK directly suppressed the expression of PGC-1α and genes of oxidative phosphorylation (OXPHOS) in cardiomyocytes. Systemic sTWEAK application after MI resulted in reduced left ventricular function and increased mortality without changes in interstitial fibrosis or infarct size. Molecular analysis revealed decreased phosphorylation of PI3K/Akt and ERK1/2 pathways associated with reduced expression of PGC-1α and PPARα. Likewise, expression of OXPHOS genes such as atp5O, cycs, cox5b, and ndufb5 was also reduced. Fn14 −/− mice showed significantly improved left ventricular function and PGC-1α levels after MI compared to their respective WT littermates (Fn14 +/+). Finally, inhibition of intrinsic TWEAK with anti-TWEAK antibodies resulted in improved left ventricular function and survival. Conclusions. TWEAK exerted maladaptive effects in mice after myocardial infarction most likely via direct effects on cardiomyocytes. Analysis of the potential mechanisms revealed that TWEAK reduced metabolic adaptations to increased cardiac workload by inhibition of PGC-1α.

Inter- Not Intraindividual Differences in sTWEAK Levels Predict Functional Deterioration and Mortality in Patients with Dilated Cardiomyopathy

Background. TNF-like weak inducer of apoptosis (TWEAK) has been reported to predict mortality in patients with dilated cardiomyopathy. However, whether it can be used as a biomarker for disease monitoring or rather represents a risk factor for disease progression remains unclear. Aim of the Study. To evaluate the potential of sTWEAK as a biomarker in patients with dilated cardiomyopathy. Results. We conducted a serial study of sTWEAK levels in 78 patients with dilated cardiomyopathy. Soluble TWEAK levels predicted not only a combined mortality/heart transplantation endpoint after 4 years (P = 0.0001), but also the risk for clinical deterioration (P = 0.0001). Compared to NT-proBNP, sTWEAK remained relatively stable in individual patients on follow-up indicating that inter- rather than intraindividual differences in sTWEAK levels predicted outcome. Finally, neither did the scavenger receptor sCD163 correlate with sTWEAK levels nor did its determination add additional information on outcome in patients with dilated cardiomyopathy. Conclusion. Soluble TWEAK levels in patients with dilated cardiomyopathy may not be of value for disease monitoring but may represent a risk factor for disease progression and death. Further research will be necessary to elucidate the exact role of sTWEAK as a potential modulator of immune response in the setting of dilated cardiomyopathy.

Feasibility and safety of vitamin K antagonist monotherapy in atrial fibrillation patients undergoing transcatheter aortic valve implantation

AIMS We aimed to assess the efficacy and safety of vitamin K antagonist (VKA) monotherapy in atrial fibrillation (AF) patients undergoing transcatheter aortic valve implantation (TAVI). METHODS AND RESULTS In 735 TAVIs since 2008 we identified 167 patients suffering from concomitant AF who received either VKA monotherapy (n=77), VKA plus single antiplatelet therapy (SAPT, n=41) or a triple anticoagulation regimen (n=49). Thromboembolic as well as bleeding complications were analysed for six months after TAVI. Only one minor bleeding and no thromboembolic events occurred after VKA therapy had been initiated post TAVI. Compared to patients being treated with additional either single or dual antiplatelet therapy, the incidence of major/life-threatening bleeding complications was significantly lower in the VKA mono group (0/77 [VKA mono] vs. 3/41 [VKA+SAPT; p=0.04] vs. 4/49 [triple anticoagulation; p=0.02]). Analysis of a combined endpoint of post-procedural death, stroke, embolism and major bleeding revealed a significant superiority of VKA monotherapy compared to VKA plus SAPT or DAPT, respectively (5/77 vs. 9/41 [p=0.02] vs. 14/49 [p=0.002]). CONCLUSIONS VKA therapy without additional antiplatelet treatment is effective and safe in AF patients undergoing TAVI.

Procedural advantages of a novel coronary stent design with ultra-thin struts and bioabsorbable abluminal polymer coating in an all-comers registry

Introduction The implications of novel drug-eluting stent (DES) design modifications including ultra-thin struts and new concepts of polymer coating for procedural efficacy are still unknown. Aim To evaluate procedural efficacy and short-term safety of a novel DES design. Material and methods In this all-comers registry, 407 consecutive patients were enrolled upon undergoing percutaneous coronary interventions (PCI) with the thin-strut bioabsorbable abluminal polymer-coated SYNERGY stent. These patients were then compared with the previous 407 patients undergoing PCI performed by the same interventionalists using currently established second-generation DES (Promus Element plus, Xience prime, Resolute Integrity). Several clinical and procedural data were compared, and the coronary artery complexity was assessed by the American College of Cardiology/American Heart Association classification and SYNTAX Score. Results The study population consisted of 814 patients. A total of 859 Synergy stents were deployed in 480 target vessels in the Synergy group (n = 407), and 904 stents in 469 vessels in the second-generation DES group (n = 407). Coincidentally, target lesions in the Synergy group (A 2.7%, B1 13.8%, B2 38.6%, C 45.0%) were more complex (p < 0.01) than those in the second-generation DES group (A 4.9%, B1 18.7%, B2 42.3%, C 34.2%). In cases with severe lesions (B2/C), the median contrast agent amount and fluoroscopy time were significantly lower in the Synergy group, indicating improved deliverability (110 ml vs. 150 ml; p < 0.01 and 7.2 min vs. 9.1 min; p = 0.01). Rates of in-hospital major adverse cardiovascular events were comparable between the two groups. Conclusions In an all-comers, real-world PCI population, novel stent design modifications including ultra-thin struts and abluminal bioabsorbable polymer coating are associated with improved procedural performance.

Short and long-term results after endovascular management of vascular complications during transfemoral aortic valve implantation

Abstract Background Vascular injury and access site complications in the contemporary setting of transcatheter aortic valve implantation (TAVI) are known to be associated with increased mortality and morbidity. The aim of our study was to analyse the feasibility and safety of percutaneous treatment of such vascular complications using a stent graft. Methods Between January 2010 and April 2013, 36 TAVI patients developed severe access site complications and underwent subsequent interventional treatment with a covered stent. Acute treatment success was confirmed by angiography immediately after the implantation of the stent graft, with clinical long-term patency follow-up being assessed by duplex ultrasound. Results Of the 36 patients evaluated, percutaneous treatment of the acute access site bleeding was successful in 35 patients (97%), with one patient requiring surgical intervention due to insufficient haemostasis after stent graft implantation. A subset of 5 patients underwent successful ipsilateral stent graft implantation, either because crossover sheath placement was not feasible (n = 1), or intentionally with an even sheathless approach in an effort to reduce vessel injury (n = 4). After a mean follow-up of 22 ± 8 months, stent graft patency was confirmed by duplex ultrasound in 13 patients with an additional 5 patients reporting to be free from symptoms and claudication. Thirteen patients died within the first 24 months after the procedure, however, none was due to access vessel complications. Five patients were lost for follow-up. Conclusions Our data confirm that endovascular treatment of access site complications related to TAVI is feasible, safe and efficacious, resulting in long-term vascular patency.