Transforming growth factor-ß1 promotes fibrosis but attenuates calcification of valvular tissue applied as a three-dimensional calcific aortic valve disease model.

Calcific aortic valve disease (CAVD) is characterized by valvular fibrosis and calcification and driven by differentiating valvular interstitial cells (VICs). Expression data from patient biopsies suggest that transforming growth factor (TGF)-ß1 is implicated in CAVD pathogenesis. However, CAVD models using isolated VICs failed to deliver clear evidence on the role of TGF-ß1. Thus, employing cultures of aortic valve leaflets, we investigated effects of TGF-ß1 in a tissue-based three-dimensional (3-D) CAVD model. We found that TGF-ß1 induced phosphorylation of Mothers against decapentaplegic homolog (SMAD) 3 and expression of SMAD7, indicating effective downstream signal transduction in valvular tissue. Thus, TGF-ß1 increased VIC contents of rough endoplasmic reticulum, Golgi, and secretory vesicles as well as tissue levels of RNA and protein. In addition, TGF-ß1 raised expression of proliferation marker cyclin D1, attenuated VIC apoptosis, and upregulated VIC density. Moreover, TGF-ß1 intensified myofibroblastic VIC differentiation as evidenced by increased α-smooth muscle actin and collagen type I along with diminished vimentin expression. In contrast, TGF-ß1 attenuated phosphorylation of SMAD1/5/8 and upregulation of ß-catenin while inhibiting osteoblastic VIC differentiation as revealed by downregulation of osteocalcin expression, alkaline phosphatase activity, and extracellular matrix incorporation of hydroxyapatite. Collectively, these effects resulted in blocking of valvular tissue calcification and associated disintegration of collagen fibers. Instead, TGF-ß1 induced development of fibrosis. Overall, in a tissue-based 3-D CAVD model, TGF-ß1 intensifies expressional and proliferative activation along with myofibroblastic differentiation of VICs, thus triggering dominant fibrosis. Simultaneously, by inhibiting SMAD1/5/8 activation and canonical Wnt/ß-catenin signaling, TGF-ß1 attenuates osteoblastic VIC differentiation, thus blocking valvular tissue calcification. These findings question a general phase-independent CAVD-promoting role of TGF-ß1.NEW & NOTEWORTHY Employing aortic valve leaflets as a tissue-based three-dimensional disease model, our study investigates the role of transforming growth factor (TGF)-ß1 in calcific aortic valve disease pathogenesis. We find that, by activating Mothers against decapentaplegic homolog 3, TGF-ß1 intensifies expressional and proliferative activation along with myofibroblastic differentiation of valvular interstitial cells, thus triggering dominant fibrosis. Simultaneously, by inhibiting activation of Mothers against decapentaplegic homolog 1/5/8 and canonical Wnt/ß-catenin signaling, TGF-ß1 attenuates apoptosis and osteoblastic differentiation of valvular interstitial cells, thus blocking valvular tissue calcification. These findings question a general phase-independent calcific aortic valve disease-promoting role of TGF-ß1.

The combination approach with Rhokinase inhibition and mechanical circulatory support in myocardial ischemia-reperfusion injury: Rho-kinase inhibition and ventricular unloading.

BACKGROUND: It remains unclear whether the Rho-kinase (ROCK) inhibition in combination with mechanical circulatory support (MCS) had a synergic protective effect on myocardial ischemia (MI)/reperfusion injury in therapeutic strategies for acute myocardial infarction (AMI). We report the results of an approach using a rat model consisting of a miniaturized cardiopulmonary bypass (CPB) and AMI. METHODS: A total of 25 male Wistar rats were randomized into 5 groups: (1) Sham: a suture was passed under the left anterior descending artery (LAD) creating no MI. A vehicle solution (0.9% saline) was injected intraperitoneally. (2) Myocardial ischemia (MI) + vehicle (MI + V): LAD was ligated for 30 min and reperfused for 120 min, followed by administration of vehicle solution. (3) MI + fasudil (MI + F): the work sequence of group 2, but the selective ROCK inhibitor fasudil (10 mg/kg) was administered instead. (4) MI + V + CPB: CPB was initiated 15 min after the ligation of the LAD to the end of the reperfusion, in addition to the work sequence in group 2. (5) In the MI + F + CPB group, the work sequence of group 4, but with fasudil administration (10 mg/kg). RESULTS: Measurements of cardiac function through conductance catheter indicated that the drop of + dP/dt after reperfusion was moderately limited in MI + F + CPB (vs. MI + V, dP/dt p = 0.22). The preload recruitable stroke work was moderately improved in the MI + F + CPB (p = 0.23) compared with the corresponding control animals (MI + V). Phosphorylated protein kinase B expression in the MI + V + CPB and MI + F + CPB was higher than that in MI + V (p = 0.33). CONCLUSION: Therefore, fasudil administration with MCS resulted in a moderately better left ventricular performance.

AdipoRon Attenuates Inflammation and Impairment of Cardiac Function Associated With Cardiopulmonary Bypass-Induced Systemic Inflammatory Response Syndrome.

Background Cardiac surgery using cardiopulmonary bypass (CPB) frequently provokes a systemic inflammatory response syndrome, which is triggered by TLR4 (Toll-like receptor 4) and TNF-α (tumor necrosis factor α) signaling. Here, we investigated whether the adiponectin receptor 1 and 2 agonist AdipoRon modulates CPB-induced inflammation and cardiac dysfunction. Methods and Results Rats underwent CPB with deep hypothermic circulatory arrest and were finally weaned from the heart-lung machine. Compared with vehicle, AdipoRon application attenuated the CPB-induced impairment of mean arterial pressure following deep hypothermic circulatory arrest. During the weaning and postweaning phases, heart rate and mean arterial pressure in all AdipoRon animals (7 of 7) remained stable, while cardiac rhythm was irretrievably lost in 2 of 7 of the vehicle-treated animals. The AdipoRon-mediated improvements of cardiocirculatory parameters were accompanied by increased plasma levels of IL (interleukin) 10 and diminished concentrations of lactate and K+. In myocardial tissue, AdipoRon activated AMP-activated protein kinase (AMPK) while attenuating CPB-induced degradation of nuclear factor κB inhibitor α (IκBα), upregulation of TNF-α, IL-1ß, CCL2 (C-C chemokine ligand 2), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and inducible nitric oxide synthase. Correspondingly, in cultured cardiac myocytes, cardiac fibroblasts, and vascular endothelial cells, AdipoRon activated AMPK, upregulated IL-10, and attenuated activation of nuclear factor κB, as well as upregulation of TNF-α, IL-1ß, CCL2, NADPH oxidase, and inducible nitric oxide synthase induced by lipopolysaccharide or TNF-α. In addition, the treatment of cardiac myocytes with the AMPK activator 5-aminoimidazole-4-carboxamide 1-ß-D-ribofuranoside resulted in a similar inhibition of lipopolysaccharide- and TNF-α-induced inflammatory cell phenotypes as for AdipoRon. Conclusions Our observations indicate that AdipoRon attenuates CPB-induced inflammation and impairment of cardiac function through AMPK-mediated inhibition of proinflammatory TLR4 and TNF-α signaling in cardiac cells and upregulation of immunosuppressive IL-10.

Targeting of cell-free DNA by DNase I diminishes endothelial dysfunction and inflammation in a rat model of cardiopulmonary bypass.

The use of cardiopulmonary bypass (CPB) results in the activation of leukocytes, release of neutrophil extracellular traps (NETs) and severe inflammation. We hypothesize that targeting of circulating cell-free DNA (cfDNA) by DNases might represent a feasible therapeutic strategy to limit CPB-associated side effects. Male Wistar rats (n = 24) underwent CPB with deep hypothermic circulatory arrest (DHCA) and were divided into 3 groups: control (group 1), one i.v. bolus DNase I before CPB start (group 2) and a second DNase I dose before reperfusion (group 3). We found a positive correlation between plasma cfDNA/NETs levels and compromised endothelial vasorelaxation after CPB. DNase I administration significantly diminished plasma cfDNA/NETs levels. Further, a dose-dependent improvement in endothelial function accompanied by significant reduction of circulating intercellular adhesion molecule (ICAM)-1 was observed. Rats of group 3 had significantly reduced plasma IL-6 levels and downregulated expression of adhesion molecules resulting in impaired leukocyte extravasation and reduced MPO activity in lungs. Mechanistically, digestion of NETs by DNase I significantly diminished NETs-dependent upregulation of adhesion molecules in human endothelial cells. Altogether, systemic DNase I administration during CPB efficiently reduced cfDNA/NETs-mediated endothelial dysfunction and inflammation and might represents a promising therapeutic strategy for clinical practice.