Potential Role of H-Ferritin in Mitigating Valvular Mineralization.

Objective- Calcific aortic valve disease is a prominent finding in elderly and in patients with chronic kidney disease. We investigated the potential role of iron metabolism in the pathogenesis of calcific aortic valve disease. Approach and Results- Cultured valvular interstitial cells of stenotic aortic valve with calcification from patients undergoing valve replacement exhibited significant susceptibility to mineralization/osteoblastic transdifferentiation in response to phosphate. This process was abrogated by iron via induction of H-ferritin as reflected by lowering ALP and osteocalcin secretion and preventing extracellular calcium deposition. Cellular phosphate uptake and accumulation of lysosomal phosphate were decreased. Accordingly, expression of phosphate transporters Pit1 and Pit2 were repressed. Translocation of ferritin into lysosomes occurred with high phosphate-binding capacity. Importantly, ferritin reduced nuclear accumulation of RUNX2 (Runt-related transcription factor 2), and as a reciprocal effect, it enhanced nuclear localization of transcription factor Sox9 (SRY [sex-determining region Y]-box 9). Pyrophosphate generation was also increased via upregulation of ENPP2 (ectonucleotide pyrophosphatase/phosphodiesterase-2). 3H-1, 2-dithiole-3-thione mimicked these beneficial effects in valvular interstitial cell via induction of H-ferritin. Ferroxidase activity of H-ferritin was essential for this function, as ceruloplasmin exhibited similar inhibitory functions. Histological analysis of stenotic aortic valve revealed high expression of H-ferritin without iron accumulation and its relative dominance over ALP in noncalcified regions. Increased expression of H-ferritin accompanied by elevation of TNF-α (tumor necrosis factor-α) and IL-1ß (interleukin-1ß) levels, inducers of H-ferritin, corroborates the essential role of ferritin/ferroxidase via attenuating inflammation in calcific aortic valve disease. Conclusions- Our results indicate that H-ferritin is a stratagem in mitigating valvular mineralization/osteoblastic differentiation. Utilization of 3H-1, 2-dithiole-3-thione to induce ferritin expression may prove a novel therapeutic potential in valvular mineralization.

[Perioperative use of levosimendan in cardiac surgery. Hungarian recommendation]. / A levoszimendán perioperatív alkalmazása a szívsebészetben. Magyar ajánlás.

Low output syndrome significantly increases morbidity and mortality of cardiac surgery and lengthens the durations of intensive care unit and hospital stays. Its treatment by catecholamines can lead to undesirable systemic and cardiac complications. Levosimendan is a calcium sensitiser and adenosine triphosphate (ATP)-sensitive potassium channel (IK,ATP) opener agent. Due to these effects, it improves myocardium performance, does not influence adversely the balance between O2 supply and demand, and possesses cardioprotective and organ protective properties as well. Based on the scientific literature and experts' opinions, a European recommendation was published on the perioperative use of levosimendan in cardiac surgery in 2015. Along this line, and also taking into consideration cardiac surgeon, anaesthesiologist and cardiologist representatives of the seven Hungarian heart centres and the children heart centre, the Hungarian recommendation has been formulated that is based on two pillars: literature evidence and Hungarian expert opinions. The reviewed fields are: coronary and valvular surgery, assist device implantation, heart transplantation both in adult and pediatric cardiologic practice. Orv Hetil. 2018; 159(22): 870-877.

Surgical Management and Outcome of Renal Cell Carcinoma with Inferior Vena Cava Tumor Thrombus.

INTRODUCTION: The authors of this paper assessed the surgical management and outcome of renal cancers when tumor thrombus extended into the inferior vena cava (IVC). METHODS: From 2000 to 2015, 46 radical nephrectomies were performed on patients with tumor thrombus in the IVC. The mean age of the patients was 60 ± 11 years. Radical nephrectomy and thrombectomies were performed in a single session. There were 18 level-IV, 23 level-III, and 5 level-II tumor thrombi. The operations were performed using cardiopulmonary bypass in 14 patients, while deep hypothermic cardiac arrest was carried out in 4 cases. RESULTS: The mean size of the tumors was 9.4 ± 3.5 cm. Histology showed the tumor stages to be pT3b in 21cases, pT3c in 22, and pT4 in 3 patients. The mean follow-up period of the patients was 3.6 ± 3.0 years. During the follow-up period, local recurrence was observed in 7 patients, while distant metastases occurred in 8 cases. The median time to progression was 37 ± 27 months. The 5-year overall survival was 43.7%. CONCLUSIONS: Radical nephrectomy and thrombectomy provided reasonable long-term survival for patients with renal cancer and IVC thrombus. However, tumor progression was detected in 41.6%. The presence of tumor thrombus had a negative effect on tumor progression and survival.

Intraoperative ventilation strategy during cardiopulmonary bypass attenuates the release of matrix metalloproteinases and improves oxygenation.

BACKGROUND: Patients undergoing open heart surgery with cardiopulmonary bypass (CPB) often develop a systemic immune reaction, characterized by an increase of proinflammatory and anti-inflammatory mediators. We previously demonstrated that continued mechanical ventilation during CPB reduces this response. We hypothesized that this strategy may also impact on matrix metalloproteinase (MMP) release. MATERIAL AND METHODS: Thirty consecutive patients undergoing coronary artery bypass grafting with CPB were randomized into a ventilated (VG) (n = 15) and a standard non-ventilated group (NVG) (n = 15). Blood was collected at the beginning, at the end of surgery, and on the five consecutive days. MMPs, tissue inhibitor of matrix metalloproteinase 1 (TIMP-1), and lipocalin 2 (LCN2) were measured by enzyme-linked immunosorbent assay. Parameters of transpulmonary oxygen transport were assessed at different time points. RESULTS: MMP-8, MMP-9, and LCN2 were significantly lower at the end of surgery in VG compared with those in NVG patients (MMP-8 [ng/mL]: 7.1 [3.5] versus 12.5 [7.7], P = 0.02; MMP-9 [ng/mL]: 108 [42] versus 171 [98], P = 0.029; LCN2 [ng/mL]: 109 [42] versus 171 [98], P = 0.03). TIMP-1 concentrations were lower on postoperative day one, (TIMP-1 [ng/mL]: 174 [55] versus 273 [104], P = 0.003), whereas MMP-3 levels were lower on postoperative days four and five (MMP-3 [ng/mL]: 44 [17] versus 67 [35], P = 0.026). The arterial partial pressure of oxygen/fraction of inspired oxygen ratio was significantly higher in VG patients throughout the postoperative observation period, which did not affect the length of postoperative ventilatory support. CONCLUSIONS: Continued mechanical ventilation during CPB reduces serum levels of MMPs, their inhibitor TIMP-1 and LCN2, which preserves MMP-9 activity. The present study suggests that continued mechanical ventilation improves postoperative oxygenation and could potentially prevent aggravation of lung injury after CPB.

Decline of FOXN1 gene expression in human thymus correlates with age: possible epigenetic regulation.

BACKGROUND: Thymic involution is thought to be an important factor of age related immunodeficiency. Understanding the molecular mechanisms of human thymic senescence may lead to the discovery of novel therapeutic approaches aimed at the reestablishment of central and peripheral T cell repertoire. RESULTS: As an initial approach, here we report that the decline of human thymic FOXN1 transcription correlates with age, while other genes, DLL1, DLL4 and WNT4, essential for thymopoiesis, are constitutively transcribed. Using a human thymic epithelial cell line (hTEC), we show that FOXN1 expression is refractory to signals that induce FOXN1 transcription in primary 3D culture conditions and by stimulation of the canonical WNT signaling pathway. Blockage of FOXN1 induceability in the hTEC line may be mediated by an epigenetic mechanism, the CpG methylation of the FOXN1 gene. CONCLUSION: We showed a suppression of FOXN1 transcription both in cultured human thymic epithelial cells and in the aging thymus. We hypothesize that the underlying mechanism may be associated with changes of the DNA methylation state of the FOXN1 gene.

[Infective endocarditis caused by Chlamydia pneumoniae after liver transplantation. Case report]. / Chlamydia pneumoniae okozta infektív endocarditis májtranszplantációt követoen.

The incidence of infective endocarditis is underestimated in solid organ transplant recipients. The spectrum of pathogens is different from the general population. The authors report the successful treatment of a 58-year-old woman with infective endocarditis caused by atypical microorganism and presented with atypical manifestations. Past history of the patient included alcoholic liver cirrhosis and cadaver liver transplantation in February 2000. One year after liver transplantation hepatitis B virus infection was diagnosed and treated with antiviral agents. In July 2007 hemodialysis was started due to progressive chronic kidney disease caused by calcineurin toxicity. In November 2013 the patient presented with transient aphasia. Transesophageal echocardiography revealed vegetation in the aortic valve and brain embolization was identified on magnetic resonance images. Initial treatment consisted of a 4-week regimen with ceftriaxone (2 g daily) and gentamycin (60 mg after hemodialysis). Blood cultures were all negative while serology revealed high titre of antibodies against Chlamydia pneumoniae. Moxifloxacin was added as an anti-chlamydial agent, but neurologic symptoms returned. After coronarography, valvular surgery and coronary artery bypass surgery were performed which resulted in full clinical recovery of the patient.

Low tidal volume ventilation during cardiopulmonary bypass reduces postoperative chemokine serum concentrations.

BACKGROUND: Open-heart surgery with cardiopulmonary bypass (CPB) is associated with a generalized immune response and postoperative lung dysfunction. Chemokines are involved in the pathogenesis of postoperative lung dysfunction. We investigated whether continued mechanical ventilation during CPB has an impact on chemokine serum concentrations. METHODS: A total of 30 patients undergoing coronary artery bypass graft operation were randomized to either continuous ventilated group (n=15) or nonventilated group (n=15). Blood samples were drawn at the beginning and at the end of surgery and on the 5 consecutive days. Serum CCL2, CCL4, and CCL20 concentrations were measured and given as mean ± standard deviation. RESULTS: Chemokine concentrations were elevated at the end of surgery in both groups. CCL2 and CCL4 levels returned to baseline on postoperative day (POD)-1 in the ventilation group and stayed elevated in the nonventilation group. CCL4 serum levels were significantly lower in ventilated-group patients on POD-1 (10.9 [39.0] vs. 153.2 [168.1]; p=0.005), POD-2 (16.8 [36.8] vs. 147.9 [165.4]; p=0.019), POD-3 (14.2 [24.0] vs. 97.9 [87.1]; p=0.005), and POD-5 (6.5 [25.0] vs. 33.6 [38.4]; p=0.045). CONCLUSION: Continued mechanical ventilation during CPB results in reduced CCL4 concentrations on POD-1 to -5.

Approximation of A1 adenosine receptor reserve appertaining to the direct negative inotropic effect of adenosine in hyperthyroid guinea pig left atria.

Hyperthyroidism elevates cardiovascular mortality by several mechanisms, including increased risk of ischemic heart disease. Therefore, therapeutic strategies, which enhance tolerance of heart to ischemia-reperfusion injury, may be particularly useful for hyperthyroid patients. One promising cardioprotective approach is use of agents that cause (directly or indirectly) A1 adenosine receptor (A1 receptor) activation, since A1 adenosinergic pathways initiate protective mechanisms such as ischemic preconditioning. However, previously we found great A1 receptor reserve for the direct negative inotropic effect of adenosine in isolated guinea pig atria. This phenomenon suggests that weakening of atria is a possible side effect of A1 adenosinergic stimulant agents. Thus, the goal of the present investigation was to explore this receptor reserve in hyperthyroidism. Our recently developed method was used that prevents the rapid intracellular elimination of adenosine, allowing sufficient time for exogenous adenosine administered for the generation of concentration-response curves to exert its effect. Our method also allowed correction for the bias caused by the consequent endogenous adenosine accumulation. Our results demonstrate that thyroxine treatment does not substantially affect the A1 receptor reserve for the direct negative inotropic effect of adenosine. Consequently, if an agent causing A1 receptor activation is administered for any indication, the most probable adverse effect affecting the heart may be a decrease of atrial contractility in both eu- and hyperthyroid conditions.

Performance of EuroSCORE II in Hungary: a single-centre validation study.

BACKGROUND: The efficacy of the updated cardiac surgical risk stratification system, EuroSCORE II, needs widespread assessment in the cardiac surgical centres where it is intended to be used. The present paper is a single-centre validation study carried out in Hungary. METHODS: An adult cardiac surgical cohort of 2287 patients was investigated. The general levels of performance of the logistic EuroSCORE and that of EuroSCORE II were compared using the Hosmer-Lemeshow test, ROC analysis and calculation of the Brier score. The calibrations were visualised by smoothed curves derived with the help of local polynomial regression. The efficacy of EuroSCORE II was analysed in different operation types and urgency subgroups. RESULTS: The old EuroSCORE over-estimated the risk (O:E ratio: 0.66, HL test, p < 0.01), while EuroSCORE II slightly under-predicted mortality (O:E ratio:1.19, HL test, p = 0.0084). Comparing the ROC AUCs, we did not find a significant difference between the accuracy of the old and new versions of EuroSCORE (0.8017, 95% CI: 0.7596-0.8438 vs. 0.8177 95% CI: 0.7786-0.8569). EuroSCORE II performed well among CABG patients (O:E ratio: 0.75, HL test, p = 0.5789) and in those who underwent elective surgery (O:E ratio: 1.1, HL test, p = 0.1396), but failed in the emergency (O:E ratio: 1.71, HL test, p = 0.0055) and salvage (O:E ratio:1.36, HL test, p = 0.0245) categories. CONCLUSIONS: EuroSCORE II proved to be more suitable for cardiac surgical risk prediction compared with its previous version, but its reliability can be questioned among patients who need emergency and salvage surgery, as well as in the case of combined operations.

Hydrogen sulfide as an anti-calcification stratagem in human aortic valve: Altered biogenesis and mitochondrial metabolism of H2S lead to H2S deficiency in calcific aortic valve disease.

Hydrogen sulfide (H2S) was previously revealed to inhibit osteoblastic differentiation of valvular interstitial cells (VICs), a pathological feature in calcific aortic valve disease (CAVD). This study aimed to explore the metabolic control of H2S levels in human aortic valves. Lower levels of bioavailable H2S and higher levels of interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) were detected in aortic valves of CAVD patients compared to healthy individuals, accompanied by higher expression of cystathionine γ-lyase (CSE) and same expression of cystathionine ß-synthase (CBS). Increased biogenesis of H2S by CSE was found in the aortic valves of CAVD patients which is supported by increased production of lanthionine. In accordance, healthy human aortic VICs mimic human pathology under calcifying conditions, as elevated CSE expression is associated with low levels of H2S. The expression of mitochondrial enzymes involved in H2S catabolism including sulfide quinone oxidoreductase (SQR), the key enzyme in mitochondrial H2S oxidation, persulfide dioxygenase (ETHE1), sulfite oxidase (SO) and thiosulfate sulfurtransferase (TST) were up-regulated in calcific aortic valve tissues, and a similar expression pattern was observed in response to high phosphate levels in VICs. AP39, a mitochondria-targeting H2S donor, rescued VICs from an osteoblastic phenotype switch and reduced the expression of IL-1ß and TNF-α in VICs. Both pro-inflammatory cytokines aggravated calcification and osteoblastic differentiation of VICs derived from the calcific aortic valves. In contrast, IL-1ß and TNF-α provided an early and transient inhibition of VICs calcification and osteoblastic differentiation in healthy cells and that effect was lost as H2S levels decreased. The benefit was mediated via CSE induction and H2S generation. We conclude that decreased levels of bioavailable H2S in human calcific aortic valves result from an increased H2S metabolism that facilitates the development of CAVD. CSE/H2S represent a pathway that reverses the action of calcifying stimuli.

Lower whole blood selenium level is associated with higher operative risk and mortality following cardiac surgery.

PURPOSE: The authors intended to test their hypothesis that a low blood selenium level is associated with higher mortality, morbidity, and increased inflammatory response following cardiac surgery. METHODS: A single-center clinical survey was conducted on 197 consecutive patients undergoing on-pump operation in Debrecen, Hungary. Blood samples for whole blood selenium analysis were taken immediately before the surgery. Their risk profiles were evaluated according to the EuroSCORE. The outcome parameters were as follows: 30-day mortality, incidence of systemic inflammatory response syndrome, and cardiac and renal dysfunction. The main laboratory outcome variables were the postoperative concentrations of C-reactive protein and cardiac troponin I. RESULTS: The mean blood selenium level was significantly lower in non-survivors 102.2 ± 19.5 µg/L compared with survivors 111.1 ± 16.9 µg/L (p = 0.047), and the mean age, EuroSCORE values, and troponin concentrations were significantly higher in the non-survivors. To exclude these potential confounders a logistic regression model was fitted to our data, with mortality as the outcome and the EuroSCORE, the degree of troponin elevation, and selenium concentration as explanatory variables. This model revealed that a lower selenium level was a minor but apparently existing risk factor for postoperative mortality. CONCLUSION: Further examinations are required to clarify the question that remained unanswered in this study: the role of low selenium in the causality chain leading to higher postoperative mortality.

Nicotinamide-riboside shifts the differentiation of human primary white adipocytes to beige adipocytes impacting substrate preference and uncoupling respiration through SIRT1 activation and mitochondria-derived reactive species production.

Beige adipocytes play key roles in organismal energy and metabolic balance. In this study, we assessed whether the supplementation of human white adipocytes, differentiated from human adipose tissue-derived stem cells, with nicotinamide riboside (NR), a potent NAD + precursor, can shift differentiation to beige adipocytes (beiging). NR induced mitochondrial biogenesis and the expression of beige markers (TBX1 and UCP1) in white adipocytes demonstrating that NR can declutch beiging. NR did not induce PARP activity but supported SIRT1 induction, which plays a key role in beiging. NR induced etomoxir-resistant respiration, suggesting increases in the oxidation of carbohydrates, carbohydrate breakdown products, or amino acids. Furthermore, NR boosted oligomycin-resistant respiration corresponding to uncoupled respiration. Enhanced etomoxir and oligomycin-resistant respiration were dependent on mitochondrial reactive-species production. Taken together, NR supplementation can induce beiging and uncoupled respiration, which are beneficial for combatting metabolic diseases.

The Roles of S100A4 and the EGF/EGFR Signaling Axis in Pulmonary Hypertension with Right Ventricular Hypertrophy.

Pulmonary hypertension (PH) is characterized by increased pulmonary arterial pressure caused by the accumulation of mesenchymal-like cells in the pulmonary vasculature. PH can lead to right ventricular hypertrophy (RVH) and, ultimately, heart failure and death. In PH etiology, endothelial-to-mesenchymal transition (EndMT) has emerged as a critical process governing the conversion of endothelial cells into mesenchymal cells, and S100A4, EGF, and EGFR are implicated in EndMT. However, a potential role of S100A4, EGF, and EGFR in PH has to date not been elucidated. We therefore quantified S100A4, EGF, and EGFR in patients suffering from chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (iPAH). To determine specificity for unilateral heart disease, the EndMT biomarker signature was further compared between PH patients presenting with RVH and patients suffering from aortic valve stenosis (AVS) with left ventricular hypertrophy. Reduced S100A4 concentrations were found in CTEPH and iPAH patients with RVH. Systemic EGF was increased in CTEPH but not in iPAH, while AVS patients displayed slightly diminished EGF levels. EGFR was downregulated in all patient groups when compared to healthy controls. Longitudinal data analysis revealed no effect of surgical therapies on EndMT markers. Pulmonary thrombo-endarterectomized samples were devoid of S100A4, while S100A4 tissue expression positively correlated with higher grades of Heath-Edwards histopathological lesions of iPAH-derived lung tissue. Histologically, EGFR was not detectable in CTEPH lungs or in iPAH lesions. Together, our data suggest an intricate role for S100A4 and EGF/EGFR in PH with right heart pathology.

Human internal thoracic artery grafts exhibit severe morphological and functional damage and spasmic vasomotion due to oxidative stress.

BACKGROUND: The internal thoracic artery (ITA) is the first choice for myocardial revascularization, but atherosclerotic lesions and perioperative vasospasm may still limit its functionality. Oxidative stress via the peroxynitrite - poly-(ADP-ribose) polymerase (PARP) cascade plays an important role in the pathogenesis of impaired vascular tone via endothelial injury. We aimed to investigate and describe the histology, PARP activation and functionality of ITA grafts and to assess the possible beneficial effect of PARP-inhibition. MATERIAL/METHODS: ITA specimens from 47 patients (26 men, mean age 66.2 ± 1.7 years) who underwent coronary bypass surgery were processed for histological and immunohistochemical studies for oxidative stress and PARP activation, and were functionally tested with acetylcholine (ACh) and sodium nitroprusside (SNP) with or without PARP inhibition. RESULTS: The sections showed atherosclerotic alterations and oxidative and nitrosative stress were evidenced by positive 3-nitrotyrosine, 4-hydroxynonenal and PAR stainings. Functionally, 88.1% reacted to K-Krebs, 68.7% exhibited contraction after 1 µM phenylephrine, 29.9% exhibited relaxation to 30 µM Ach, and all precontracted segments relaxed to 30 µM SNP. High amplitude vasomotion was observed in 47.8% of the segments, which could be abolished by the application of 10 µM SNP.Incubation of the preparations with PJ34 did not improve endothelium-dependent vasodilation. CONCLUSIONS: ITA grafts are severely damaged both morphologically and functionally in patients undergoing coronary artery bypass surgery, but PARP inhibition cannot improve their functional characteristics. The topical use of SNP to the ITA during the operation may improve vascular functions by dilating the vessels and eliminating the eventual spasmic vasomotion.

Hydrogen sulfide inhibits aortic valve calcification in heart via regulating RUNX2 by NF-κB, a link between inflammation and mineralization.

INTRODUCTION: Hydrogen sulfide (H2S) was revealed to inhibit aortic valve calcification and inflammation was implicated in the pathogenesis of calcific aortic valve disease (CAVD). OBJECTIVES: We investigate whether H2S inhibits mineralization via abolishing inflammation. METHODS AND RESULTS: Expression of pro-inflammatory cytokines, interleukin-1ß (IL-1ß) and tumor necrosis factor α (TNF-α) were increased in patients with CAVD and in calcified aortic valve of ApoE-/- mice. Administration of H2 2S releasing donor (4-methoxyphenyl piperidinylphosphinodithioc acid (AP72)) exhibited inhibition on both calcification and inflammation in aortic valve of apolipoprotein E knockout mice (ApoE-/-) mice is reflected by lowering IL-1ß and TNF-α levels. Accordingly, AP72 prevented the accumulation of extracellular calcium deposition and decreased nuclear translocation of nuclear factor-κB (NF-κB) in human valvular interstitial cells (VIC). This was also accompanied by reduced cytokine response. Double-silencing of endogenous H2S producing enzymes, Cystathionine gamma-lyase (CSE) and Cystathionine beta-synthase (CBS) in VIC exerted enhanced mineralization and higher levels of IL-1ß and TNF-α. Importantly, silencing NF-κB gene or its pharmacological inhibition prevented nuclear translocation of runt-related transcription factor 2 (Runx2) and subsequently the calcification of human VIC. Increased levels of NF-κB and Runx2 and their nuclear accumulation occurred in ApoE-/- mice with a high-fat diet. Administration of AP72 decreased the expression of NF-κB and prevented its nuclear translocation in VIC of ApoE-/- mice on a high-fat diet, and that was accompanied by a lowered pro-inflammatory cytokine level. Similarly, activation of Runx2 did not occur in VIC of ApoE-/- mice treated with H2S donor. Employing Stimulated Emission Depletion (STED) nanoscopy, a strong colocalization of NF-κB and Runx2 was detected during the progression of valvular calcification. CONCLUSIONS: Hydrogen sulfide inhibits inflammation and calcification of aortic valve. Our study suggests that the regulation of Runx2 by hydrogen sulfide (CSE/CBS) occurs via NF-κB establishing a link between inflammation and mineralization in vascular calcification.

Negative Inotropic Effect of BGP-15 on the Human Right Atrial Myocardium.

Cardiovascular morbidity and mortality carry great socioeconomic burden worldwide that mandates the development of new, efficacious therapeutic agents with limited adverse effects. O-(3-piperidino-2-hydroxy-1-propyl) nicotinic acid amidoxime (BGP-15) is a known, well-tolerable drug candidate that exerts beneficial effects in several disease models. As BGP-15 has a significant structural similarity with propranolol, it arose that BGP-15 might also have a direct effect on the heart. Thus, in the present work, we investigated the effect of BGP-15 and propranolol on the contractility of isolated, paced, human right atrial samples (obtained from patients undergone open-heart surgery), with or without previous isoproterenol (ISO) stimulation (evoking an indirect or direct effect, respectively). We found that both BGP-15 and propranolol exerted direct as well as indirect negative inotropic effects on the atrial myocardium, reaching similar maximal response. However, BGP-15 had considerably smaller potency than propranolol regarding both types of negative inotropy. In addition, BGP-15, in contrast to propranolol, had a significantly greater indirect negative inotropic effect on samples exhibiting strong response to ISO. Moreover, the indirect negative inotropic effect of BGP-15 was significantly greater on samples derived from diabetic patients than on samples obtained from non-diabetic ones. Our results suggest that the enhanced ISO sensitivity is associated with the diabetic state, and BGP-15 exerts greater negative inotropic effect on the human atrial myocardium in both conditions (as compared to the atrial tissue that is not ISO oversensitive and/or diabetic). Additionally, the negative inotropic effects of BGP-15 and propranolol seem to be mediated by in part different molecular pathways in the atrial myocardium.

Hydrogen sulfide inhibits calcification of heart valves; implications for calcific aortic valve disease.

BACKGROUND AND PURPOSE: Calcification of heart valves is a frequent pathological finding in chronic kidney disease and in elderly patients. Hydrogen sulfide (H2 S) may exert anti-calcific actions. Here we investigated H2 S as an inhibitor of valvular calcification and to identify its targets in the pathogenesis. EXPERIMENTAL APPROACH: Effects of H2 S on osteoblastic transdifferentiation of valvular interstitial cells (VIC) isolated from samples of human aortic valves were studied using immunohistochemistry and western blots. We also assessed H2S on valvular calcification in apolipoprotein E-deficient (ApoE-/- ) mice. KEY RESULTS: In human VIC, H2 S from donor compounds (NaSH, Na2 S, GYY4137, AP67, and AP72) inhibited mineralization/osteoblastic transdifferentiation, dose-dependently in response to phosphate. Accumulation of calcium in the extracellular matrix and expression of osteocalcin and alkaline phosphatase was also inhibited. RUNX2 was not translocated to the nucleus and phosphate uptake was decreased. Pyrophosphate generation was increased via up-regulating ENPP2 and ANK1. Lowering endogenous production of H2 S by concomitant silencing of cystathionine γ-lyase (CSE) and cystathionine ß-synthase (CBS) favoured VIC calcification. analysis of human specimens revealed higher Expression of CSE in aorta stenosis valves with calcification (AS) was higher than in valves of aortic insufficiency (AI). In contrast, tissue H2 S generation was lower in AS valves compared to AI valves. Valvular calcification in ApoE-/- mice on a high-fat diet was inhibited by H2 S. CONCLUSIONS AND IMPLICATIONS: The endogenous CSE-CBS/H2 S system exerts anti-calcification effects in heart valves providing a novel therapeutic approach to prevent hardening of valves. LINKED ARTICLES: This article is part of a themed section on Hydrogen Sulfide in Biology & Medicine. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.4/issuetoc.

Olaparib induces browning of in vitro cultures of human primary white adipocytes.

Mitochondrial biogenesis is a key feature of energy expenditure and organismal energy balance. Genetic deletion of PARP1 or PARP2 was shown to induce mitochondrial biogenesis and energy expenditure. In line with that, PARP inhibitors were shown to induce energy expenditure in skeletal muscle. We aimed to investigate whether pharmacological inhibition of PARPs induces brown or beige adipocyte differentiation. SVF fraction of human pericardial adipose tissue was isolated and human adipose-derived mesenchymal stem cells (hADMSCs) were differentiated to white and beige adipocytes. A subset of hADMSCs were differentiated to white adipocytes in the presence of Olaparib, a potent PARP inhibitor currently in clinical use, to induce browning. Olaparib induced morphological changes (smaller lipid droplets) in white adipocytes that is a feature of brown/beige adipocytes. Furthermore, Olaparib induced mitochondrial biogenesis in white adipocytes and enhanced UCP1 expression. We showed that Olaparib treatment inhibited nuclear and cytosolic PAR formation, induced NAD+/NADH ratio and consequently boosted SIRT1 and AMPK activity and the downstream transcriptional program leading to increases in OXPHOS. Olaparib treatment did not induce the expression of beige adipocyte markers in white adipocytes, suggesting the formation of brown or brown-like adipocytes. PARP1, PARP2 and tankyrases are key players in the formation of white adipose tissue. Hereby, we show that PARP inhibition induces the transdifferentiation of white adipocytes to brown-like adipocytes suggesting that PARP activity could be a determinant of the differentiation of these adipocyte lineages.

Increased cyclooxygenase-2 expression and prostaglandin-mediated dilation in coronary arterioles of patients with diabetes mellitus.

Based on findings of experimental models of diabetes mellitus (DM) showing increased expression of vascular cyclooxygenase-2 (COX-2), we hypothesized that in patients with DM changes in COX-2-dependent prostaglandin synthesis affect vasomotor responses of coronary arterioles. Arterioles were dissected from the right atrial appendages obtained at the time of cardiac surgery of patient with DM(+) or without documented diabetes DM(-). Isolated arterioles (89+/-15 microm in diameter) were cannulated and pressurized (at 80 mm Hg), and changes in diameter were measured with video microscopy. After spontaneous tone developed [DM(-): 32+/-7%; DM(+): 37+/-5%; P=NS], arteriolar responses to bradykinin were investigated. Dilations to bradykinin (0.1 nmol/L to 1 micromol/L) were significantly (P<0.05) greater in DM(+) than DM(-) patients (10 nmol/L: 77+/-10% versus 38+/-14%). In both groups, dilations were similar to the NO-donor, sodium nitroprusside. In arterioles of DM(+), but not those of DM(-), patients' bradykinin-induced dilations were reduced by the nonselective COX inhibitor indomethacin or by the selective COX-2 inhibitor NS-398 (DM(+) at 10 nmol/L: to 20+/-4% and 29+/-7%, respectively). Correspondingly, a marked COX-2 immunostaining was detected in coronary arterioles of DM(+), but not in those of DM(-) patients. We conclude that in coronary arterioles of diabetic patients bradykinin induces enhanced COX-2-derived prostaglandin-mediated dilation. These findings are the first to show that in humans diabetes mellitus increases COX-2 expression and dilator prostaglandin synthesis in coronary arterioles, which may serve to increase dilator capacity and maintain adequate perfusion of cardiac tissues.

Adaptation of vasomotor function of human coronary arterioles to the simultaneous presence of obesity and hypertension.

OBJECTIVES: We hypothesized that simultaneous presence of obesity and hypertension activates adaptive vascular mechanisms affecting dilations of human coronary arterioles. METHODS AND RESULTS: Agonist-induced dilations were assessed in isolated pressurized coronary arterioles from patients (n=38) who underwent cardiac surgery. Among normotensives we found that dilations to bradykinin (BK) and the NO-donor, sodium-nitroprusside (SNP) were reduced in obese subjects (BK, 10(-7) mol/L, lean: 90+/-4%, obese: 64+/-7%; SNP, 10(-6) mol/L, lean: 89+/-7%, obese: 76+/-5%). However, among hypertensives, both BK- and SNP-induced dilations were significantly enhanced in obese patients, when compared with lean individuals (BK, lean: 71+/-7%, obese: 85+/-3%; SNP, lean: 60+/-6%, obese: 83+/-2%). Correspondingly, in hypertensive patients, but not in those of normotensives, a positive correlation was found between body mass index (BMI) and BK-induced (P=0.036, r=0.46), and also SNP-evoked (P=0.031, r=0.44) coronary dilations. Moreover, in additional 55 hypertensive patients flow-mediated (FMD) and nitroglycerin (NTG)-induced dilations of the brachial artery were assessed. In obese hypertensive individuals, FMD- and NTG-induced dilations were greater (FMD: 6.2+/-0.7%, NTG: 17.2+/-0.9%), than in lean hypertensive patients (FMD: 3.7+/-0.6%, NTG: 13.6+/-1.1%). Correspondingly, FMD- and NTG-induced dilations were positively correlated with BMI (P=0.020, r=0.31 and P=0.033, r=0.29, respectively). CONCLUSIONS: These findings are the first to suggest that obesity may lead to activation of adaptive vascular mechanisms to enhance the dilator function of coronary and peripheral arterial vessels in hypertensive patients.