Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Burgermeister Found Wien-Project number : 21001 Introduction Diabetic cardiomyopathy (CMP) is a complex manifestation of diabetes-linked cardiac and vascular dysfunction, but the molecular pathogenesis is still largely unknown. Notably the expression of Tenascin-C (TNC), an extracellular matrix glycoprotein, contributes to the development of cardiovascular diseases and diabetic patients have elevated serum TNC levels. However, the role and mechanism of TNC to diabetic CMP progression remains elusive. Purpose Here, we longitudinally evaluated functional and molecular role of TNC in CMP-induced cardiovascular dysfunction in a murine model. In addition, we used RNA sequencing with cardiac tissues from non-diabetic and diabetic wild type (wt) and TNC KO mice for further investigation. Methods Diabetes was induced in adult male mice, wt (AJ) and TNC-KO strains, by repeated Streptozotocin (STZ) injections (50 mg/kg). Echocardiography, myography, hemodynamics, histology, molecular and cellular analyses were performed to assess the role of TNC in diabetes-associated CV complications. Additionally, RNA-sequencing was analyzed in left ventricular (LV) tissue samples from diabetic and non-diabetic wt and TNC-KO mice providing further molecular insights. Results TNC KO mice showed preserved LV ejection fraction, and endothelium-dependent relaxation (p<0.05 and p<0.001, respectively), reduced cardiac fibrosis and distinctive coronary vessel characteristics, implying enhanced LV perfusion. In addition, the plasma levels of oxidative stress marker malondialdehyde was significantly alleviated in TNC KO diabetic mice in comparison to diabetic wt mice. Cardiomyocytes from diabetic wt mice exhibited stiffness (Fpassive and Factive), which was corrected to control level in cardiomyocytes from TNC KO diabetic hearts. Further, ex vivo isolated heart experiments demonstrated that the administration of recombinant human TNC (80 ng/ml) resulted in a significant reduction in LV hemodynamics (p<0.01) and myocardial energetics (ATP levels, p<0.01). Analysis of RNA sequencing data demonstrated that decreased expression of matrix remodeling genes Serpin1 and Ccn1 links to alleviation of fibrosis in TNC KO diabetic heart. Furthermore, Gene Ontology (GO) enrichment analysis shed light on mitochondrial changes in diabetic hearts. Our pathway analysis also identified that Hsp90aa1 as a crucial gene associated with preprotein import into the mitochondrial membrane, may suggest potential mitochondrial dysfunction in diabetic hearts. Conclusion In conclusion, lack of TNC improved long-term cardiac function in diabetes by reducing cardiac fibrosis, vascular dysfunction, oxidative stress and cardiac energetics. Thus, inhibition of TNC may prevent the diabetic heart from extensive fibrosis and energetics dysfunction that accelerates the development of HF, providing a potential targeted therapy.

Transfusion with erythrocytes stored for prolonged periods increases plasma free hemoglobin (fHb), which scavenges endogenous nitric oxide (NO). The present study aimed to investigate the effects of autologous transfusion of stored erythrocytes with or without contemporary nitric oxide administered by inhalation (iNO) in a model of pulmonary arterial hypertension (PAH). PAH was induced in 30 male Wistar rats exposed to left to right shunt (Qp/Qs > 2). After 10 weeks they were randomly treated with saline (control) or with autologous erythrocytes stored for 20 days (5 ml/h) with or without iNO (30 ppm for 60 min). fHb and NO consumption was determined in plasma. Right ventricular (RV) contractility and ventricular-vascular coupling were assessed in vivo at different pre-loads by conductance catheter. Endothelium-dependent relaxation was assessed in vitro in pulmonary artery rings. Results: Rats treaded with stored erythrocytes had significantly higher fHb plasma concentrations, which correlated with NO consumption (r = 0.75, p < 0.01). RV afterload expressed by effective pulmonary arterial elastance was higher in transfused rats but not in the group receiving contemporary iNO compared to control (Ea; 1.3 ± 0.5 vs 0.5 ± 0.3 vs. 0.6 ± 0.5 mm Hg/ml, respectively; p < 0.001). Ventricular-vascular coupling (Ees/Ea) was impaired after transfusion and this effect was completely abolished by iNO. Maximal endothelium-dependent relaxation in pulmonary artery was significantly attenuated in rats receiving transfusion but not in those receiving contemporary iNOS nor in the control (13.2 ± 1.5 vs. 38.5 ± 2.3 vs. 40.5 ± 2.0 %, respectively; p < 0.001). Transfusion with autologous stored erythrocytes worsens pulmonary arterial hypertension impairing endothelium dependent relaxation through NO scavenging by fHb. iNO completely abolish this phenomenon.

Organs from living donors seem to have a better graft function after transplantation compared to organs from brain dead and non-heart beating organ donors. We hypothesized that brain death might impair the energy status of organs and therefore systematically evaluated high energy phosphate content in organs from living, brain dead and from non-heart-beating donors in a pig model In 6 pigs brain death was induced under general anaesthesia by inflating a balloon in the epidural space. 10 hours after confirmation of brain death organs were retrieved. In 6 animals cardiac arrest was induced using 9 V direct current and mechanical and medical reanimation was performed after 10 min of ventricular fibrillation without cardiac output for 30 min. In 6 pigs organs were explanted without induction of brain death. Tissue was harvested before perfusion, after perfusion and after cold ischemia. Xanthine, hypoxanthine, adenosine-monophosphate, adenosine-diphosphate and adenosine-triphosphate were measured using high-performance liquid chromatographie. Energy charge and ATP/ADP ratio were calculated. Overall, after ischemia no difference in energy status of organs was observed between the different donor types. In all organs an increase in hypoxanthine levels and a decrease of high energy phosphate content was observed during perfusion and ischemia, irrespective of the donor type. In conclusion our hypothesis that brain death or cardiac arrest significantly impairs the energy status of donor organs did not hold true. Therefore the negative impact of brain death or cardiac arrest on graft function can not be attributed to changes in energy status.

Objectives: Endothelial lipase (EL) is established modulator of structural and functional properties of HDL. The aim of the present study was to examine the vasorelaxaing capacity of EL-modified HDL (EL-HDL).

PurposeThe study aimed to compare the acute overall hemodynamic and oxidative stress effects of intravenous S-NO-human serum albumin (S-NO-HSA) infusion and inhaled nitric oxide (iNO) in a chronic left-to-right shunt-induced pulmonary arterial hypertension model.MethodsMale Wistar rats underwent surgical creation of aorto-caval fistula (Qp/Qs> 2.0). After 10 weeks they were randomly treated with human serum albumin (HSA) (controls; n. 25), S-NO-HSA (0.5 μmol/kg/h; n. 30) or iNO (20 ppm; n. 35) for 60 minutes. Right ventricular contractility, right ventricular-vascular coupling and ventricular interdependence were assessed in vivo at different preloads by biventricular conductance catheters prior and after 60 minutes treatment. Heart and lung biopsies were obtained to determine oxidative stress by oxidized to reduced glutathione (GSSG/GSH) ratio and high-energy phosphates content.ResultsBoth S-NO-HSA and iNO led to a significant reduction in right ventricular afterload expressed by effective pulmonary arterial elastance (Ea) (from 1.3 ±0.2 to 0.5 ±0.3 and 0.4 ±0.2 respectively; P< 0.001). Only S-NO-HSA significantly improved right ventricle diastolic function (slope of end-diastolic pressure-volume relation) and contractility indicated by end-systolic elastance (Ees). Therefore a significant increase in the efficiency of ventricular-vascular coupling (Ees/Ea) occurred after S-NO-HSA but not iNO treatment (from 0.33 ±0.15 to 0.98 ±0.21; P< 0.005 and from 0.35 ±0.16 to 0.45 ±0.18; P< 0.1 respectively) with significant increase in left ventricular stroke volume (58 ±7 vs 18 ± 9 %; P< 0.003). S-NO-HSA compared to iNO improved right ventricle phosphocreatine content (27.08 ±11.35 vs. 8.41 ±1.80 nmol/mg protein; P<0.001) and myocardial energy charge (0.85 ±0.03 vs. 0.78 ±0.03; P<0.01). Both S-NO-HSA and iNO decreased lung and right ventricular GSSG/GSH ratio (P<0.001).ConclusionS-NO-HSA is more effective than iNO in treating pulmonary hypertension, improving right ventricle diastolic function and right ventricular-arterial coupling with a positive effect on ventricular interdependence. This results in superior energetic reserve of the heart, despite similar reduction of lung and right ventricular oxidative stress. PurposeThe study aimed to compare the acute overall hemodynamic and oxidative stress effects of intravenous S-NO-human serum albumin (S-NO-HSA) infusion and inhaled nitric oxide (iNO) in a chronic left-to-right shunt-induced pulmonary arterial hypertension model. The study aimed to compare the acute overall hemodynamic and oxidative stress effects of intravenous S-NO-human serum albumin (S-NO-HSA) infusion and inhaled nitric oxide (iNO) in a chronic left-to-right shunt-induced pulmonary arterial hypertension model. MethodsMale Wistar rats underwent surgical creation of aorto-caval fistula (Qp/Qs> 2.0). After 10 weeks they were randomly treated with human serum albumin (HSA) (controls; n. 25), S-NO-HSA (0.5 μmol/kg/h; n. 30) or iNO (20 ppm; n. 35) for 60 minutes. Right ventricular contractility, right ventricular-vascular coupling and ventricular interdependence were assessed in vivo at different preloads by biventricular conductance catheters prior and after 60 minutes treatment. Heart and lung biopsies were obtained to determine oxidative stress by oxidized to reduced glutathione (GSSG/GSH) ratio and high-energy phosphates content. Male Wistar rats underwent surgical creation of aorto-caval fistula (Qp/Qs> 2.0). After 10 weeks they were randomly treated with human serum albumin (HSA) (controls; n. 25), S-NO-HSA (0.5 μmol/kg/h; n. 30) or iNO (20 ppm; n. 35) for 60 minutes. Right ventricular contractility, right ventricular-vascular coupling and ventricular interdependence were assessed in vivo at different preloads by biventricular conductance catheters prior and after 60 minutes treatment. Heart and lung biopsies were obtained to determine oxidative stress by oxidized to reduced glutathione (GSSG/GSH) ratio and high-energy phosphates content. ResultsBoth S-NO-HSA and iNO led to a significant reduction in right ventricular afterload expressed by effective pulmonary arterial elastance (Ea) (from 1.3 ±0.2 to 0.5 ±0.3 and 0.4 ±0.2 respectively; P< 0.001). Only S-NO-HSA significantly improved right ventricle diastolic function (slope of end-diastolic pressure-volume relation) and contractility indicated by end-systolic elastance (Ees). Therefore a significant increase in the efficiency of ventricular-vascular coupling (Ees/Ea) occurred after S-NO-HSA but not iNO treatment (from 0.33 ±0.15 to 0.98 ±0.21; P< 0.005 and from 0.35 ±0.16 to 0.45 ±0.18; P< 0.1 respectively) with significant increase in left ventricular stroke volume (58 ±7 vs 18 ± 9 %; P< 0.003). S-NO-HSA compared to iNO improved right ventricle phosphocreatine content (27.08 ±11.35 vs. 8.41 ±1.80 nmol/mg protein; P<0.001) and myocardial energy charge (0.85 ±0.03 vs. 0.78 ±0.03; P<0.01). Both S-NO-HSA and iNO decreased lung and right ventricular GSSG/GSH ratio (P<0.001). Both S-NO-HSA and iNO led to a significant reduction in right ventricular afterload expressed by effective pulmonary arterial elastance (Ea) (from 1.3 ±0.2 to 0.5 ±0.3 and 0.4 ±0.2 respectively; P< 0.001). Only S-NO-HSA significantly improved right ventricle diastolic function (slope of end-diastolic pressure-volume relation) and contractility indicated by end-systolic elastance (Ees). Therefore a significant increase in the efficiency of ventricular-vascular coupling (Ees/Ea) occurred after S-NO-HSA but not iNO treatment (from 0.33 ±0.15 to 0.98 ±0.21; P< 0.005 and from 0.35 ±0.16 to 0.45 ±0.18; P< 0.1 respectively) with significant increase in left ventricular stroke volume (58 ±7 vs 18 ± 9 %; P< 0.003). S-NO-HSA compared to iNO improved right ventricle phosphocreatine content (27.08 ±11.35 vs. 8.41 ±1.80 nmol/mg protein; P<0.001) and myocardial energy charge (0.85 ±0.03 vs. 0.78 ±0.03; P<0.01). Both S-NO-HSA and iNO decreased lung and right ventricular GSSG/GSH ratio (P<0.001). ConclusionS-NO-HSA is more effective than iNO in treating pulmonary hypertension, improving right ventricle diastolic function and right ventricular-arterial coupling with a positive effect on ventricular interdependence. This results in superior energetic reserve of the heart, despite similar reduction of lung and right ventricular oxidative stress. S-NO-HSA is more effective than iNO in treating pulmonary hypertension, improving right ventricle diastolic function and right ventricular-arterial coupling with a positive effect on ventricular interdependence. This results in superior energetic reserve of the heart, despite similar reduction of lung and right ventricular oxidative stress.

Objectives: In this study, the efficacy of the new polarizing St Thomas' Hospital solution (STH-POL comprising esmolol, adenosine, magnesium) was compared to conventional St Thomas' Hospital solution (STH2).

Purpose To investigate the hypothesis that induction of therapeutic hypothermia with cannabinoid receptor agonist WIN55,212-2 and extracorporeal life support (ECLS) after cardiac arrest is an effective heart preservation strategy. Methods and Materials Ventricular fibrillation (VF) was induced in male Wistar rats. After 10 min of untreated VF, venoarterial ECLS was instituted and rats were randomized to three groups of ten: normothermia, therapeutic hypothermia (32°C) and pharmacological hypothermia by WIN55,212 intravenous infusion (1 mg/kg/h). After 120 minutes heterotopic heart transplantation was performed in syngeneic donors using a working heart model. After 24 hours left ventricular (LV) systolic and diastolic functions were evaluated at different preloads using a conductance catheter. Results WIN55,212-2 led to a significantly better recovery of the slope of the LV end-systolic pressure volume relationship (Ees) and Preload recruitable stroke work (PRSW) than hypothermia and normothermia: as percent of baseline 87+12 vs 54+9 vs 39+11 and 88+11 vs 59+10 vs 33+8 respectively (p.01). LV stiffness expressed by end-diastolic pressure volume relationship (EDPVR) was significantly lower after WIN55,212-2 administration (p Conclusions Pharmacologically induced hypohermia with WIN55,212-2 during ECLS improve myocardial protection through activation of the pro-survival kinase Akt and ERK and could be an organ preservation strategy after cardiac arrest.

Purpose: To compare the effect of cannabinoid receptor agonist WIN55,212-2 with mild hypothermia and normothermic control on post resuscitation outcome in a rat model of cardiac arrest. Methods: Ventricular fibrillation (VF) was induced and untreated for 10 min in adult male Sprague-Dawley rats (400-450 g). Defibrillation was attempted and resuscitated animals were randomized to three groups of ten: (a) normothermia; (b) mild therapeutic hypothermia (32°C) and (c) normothermia with WIN55,212-2 intravenous infusion (1 mg/kg/h). Cooling to 32°C and drug infusion were started at the beginning of return of spontaneous circulation and lasted for the 6 hours. The functional cardiac and neurological outcome, activated caspase-3 immunoreactivity, TUNEL and cold-inducible RNA-binding protein RBM3 were assessed at 6, 12 and 24h. Results: WIN55,212-2 administration produced pharmacologic hypothermia (32-34°C) and improved myocardial systolic and diastolic functions. Neurological deficit scores and 24-hour survival were significantly better in animals treated with WIN55,212-2 than mild therapeutic hypothermia. RNM3 expression was 5-fold after WIN,212-2 and 3-fold after mild therapeutic hypothermia compared to normothermic control (p<0.01). Cardiomyocyte apoptotic index (TUNEL) and neuronal activated caspase-3 immunoreactivity were reduced (p<0.01 and p=0.03, respectively) after WIN55,212-2 administration compared to both hypothermia and normothermia. Conclusions: Pharmacologically induced hypothermia with WIN55,212-2 induced after restoration of spontaneous circulation improved postresuscitation myocardial and neurological functions, and survival than mild therapeutic hypothermia after cardiac arrest.