Effects of BAFF Neutralization on Atherosclerosis Associated With Systemic Lupus Erythematosus.

OBJECTIVE: Cardiovascular disease (CVD) is the leading cause of death in systemic lupus erythematosus (SLE). B cells play a key role in the pathogenesis of lupus, and anti-BAFF therapy has been approved for use in SLE. Since mature B cells also promote atherosclerosis, we undertook this study to evaluate, in a mouse model and in SLE patients, whether BAFF neutralization has an atheroprotective effect in SLE. METHODS: The effect of BAFF on atherosclerosis associated with lupus was investigated in the atherosclerosis/lupus-prone apolipoprotein E-knockout D227K mouse model and in a cohort of SLE patients. Mice were treated with a blocking anti-BAFF monoclonal antibody (mAb), while fed a standard chow diet. Carotid plaque and carotid intima-media thickness were assessed by ultrasound at baseline and during follow-up in SLE patients who were asymptomatic for CVD. RESULTS: Anti-BAFF mAb in ApoE-/- D227K mice induced B cell depletion, efficiently treated lupus, and improved atherosclerosis lesions (21% decrease; P = 0.007) in mice with low plasma cholesterol levels but worsened the lesions (17% increase; P = 0.06) in mice with high cholesterol levels. The atheroprotective effect of the BAFF-BAFF receptor signaling inhibition on B cells was counterbalanced by the proatherogenic effect of the BAFF-TACI signaling inhibition on macrophages. In SLE patients, blood BAFF levels were associated with subclinical atherosclerosis (r = 0.26, P = 0.03). Anti-BAFF mAb treatment had a differential effect on the intima-media thickness progression in SLE patients depending on body mass index. CONCLUSION: Depending on the balance between lipid-induced and B cell-induced proatherogenic conditions, anti-BAFF could be detrimental or beneficial, respectively, to atherosclerosis development in SLE.

Pulmonary haemodynamic effects of interatrial shunt in heart failure with preserved ejection fraction: a preclinical study.

AIMS: The aim of this study was to evaluate the effect of the creation of a left-to-right interatrial shunt on pulmonary haemodynamics in rats with heart failure with preserved ejection fraction (HFPEF). METHODS AND RESULTS: An interatrial communication (IAC) was created in 11 healthy rats (Lewis rats) and 11 rats which developed HFPEF (36-week-old spontaneously hypertensive rats [SHR]). Effects of the interatrial shunt were compared to 11 sham-operated Lewis and 11 sham-operated SHR. At 45 days post shunt, strain effect was observed in diastolic function (E/A ratio, p<0.001; isovolumetric relaxation time, p<0.001), left atrial volume (p=0.005) and pulmonary wall shear rate (WSR) (p=0.02) measured by Doppler echo. At sacrifice of the animals (60 days), a strain effect was also noted in elastin density (p=0.003) and eNOS protein expression (p=0.001). Interatrial shunt creation resulted in (i) an increase in pulmonary WSR (p=0.04) and a decrease in left atrial volume (p<0.001), (ii) an increase in elastin density (p<0.005), and (iii) an increase in eNOS protein expression (p=0.03). CONCLUSIONS: Creation of a left-to-right atrial shunt in rats with HFPEF was effective in improving pulmonary haemodynamics. In addition, this study provides preliminary evidence of the potential risk of right volume overload and pulmonary hypertension due to atrial shunting.

Early Detection of Localized Immunity in Experimental Autoimmune Myocarditis Using [99mTc]Fucoidan SPECT.

PURPOSE: The aim of the study was to evaluate the ability of technetium-99m-fucoidan ([99mTc]fucoidan), a molecular imaging agent specific for selectins, in the assessment of early localized immunity in a rat model of experimental autoimmune myocarditis (EAM). PROCEDURES: EAM was induced in Lewis rats and troponin T; brain natriuretic peptide (BNP) and anti-myosin antibodies were measured in plasma. Separately, [99mTc]fucoidan single-photon emission computed tomography (SPECT)/x-ray computed tomography (CT) was performed in the very early phase of myocarditis at 10, 15, and 21 days after immunization. Then, hearts were collected and used for autoradiography, well counting, histology, and flow cytometry analysis. RESULTS: The EAM acute phase is characterized by extensive myocardial necrosis, release of troponin and BNP, and pericardial effusion. [99mTc]Fucoidan uptake was significantly increased in EAM compared with controls starting from D15. There was a close relationship between uptake of the tracer and myocardial content in CD45+, CD8+, CD11b+, and CD31+ cells. CONCLUSIONS: [99mTc]Fucoidan SPECT/CT accurately diagnosed the autoimmune attack in the early steps of EAM and could be used to monitor disease evolution and therapy efficiency.

Prokineticin Receptor-1 Signaling Inhibits Dose- and Time-Dependent Anthracycline-Induced Cardiovascular Toxicity Via Myocardial and Vascular Protection.

OBJECTIVES: This study investigated how different concentrations of doxorubicin (DOX) can affect the function of cardiac cells. This study also examined whether activation of prokineticin receptor (PKR)-1 by a nonpeptide agonist, IS20, prevents DOX-induced cardiovascular toxicity in mouse models. BACKGROUND: High prevalence of heart failure during and following cancer treatments remains a subject of intense research and therapeutic interest. METHODS: This study used cultured cardiomyocytes, endothelial cells (ECs), and epicardium-derived progenitor cells (EDPCs) for in vitro assays, tumor-bearing models, and acute and chronic toxicity mouse models for in vivo assays. RESULTS: Brief exposure to cardiomyocytes with high-dose DOX increased the accumulation of reactive oxygen species (ROS) by inhibiting a detoxification mechanism via stabilization of cytoplasmic nuclear factor, erythroid 2. Prolonged exposure to medium-dose DOX induced apoptosis in cardiomyocytes, ECs, and EDPCs. However, low-dose DOX promoted functional defects without inducing apoptosis in EDPCs and ECs. IS20 alleviated detrimental effects of DOX in cardiac cells by activating the serin threonin protein kinase B (Akt) or mitogen-activated protein kinase pathways. Genetic or pharmacological inactivation of PKR1 subdues these effects of IS20. In a chronic mouse model of DOX cardiotoxicity, IS20 normalized an elevated serum marker of cardiotoxicity and vascular and EDPC deficits, attenuated apoptosis and fibrosis, and improved the survival rate and cardiac function. IS20 did not interfere with the cytotoxicity or antitumor effects of DOX in breast cancer lines or in a mouse model of breast cancer, but it did attenuate the decreases in left ventricular diastolic volume induced by acute DOX treatment. CONCLUSIONS: This study identified the molecular and cellular signature of dose-dependent, DOX-mediated cardiotoxicity and provided evidence that PKR-1 is a promising target to combat cardiotoxicity of cancer treatments.

Risk of Ascending Aortic Aneurysm in Patients With Autosomal Dominant Polycystic Kidney Disease.

In recent years, simple renal cysts have been associated with an increased risk of aortic aneurysms. There is little data regarding aortic dilation in patients with autosomal dominant polycystic kidney disease (ADPKD). The aim of this study was to compare Sinuses of Valsalva (SoV) and tubular ascending aorta diameters in ADPKD patients with matched controls. From 2008 to 2016, 61 consecutive ADPKD patients who had an echocardiogram performed in our institution were matched 1:1 with controls for sex, age, blood pressure, and ß-blocker therapy use. SoV and tubular ascending aorta were measured at end-diastole, using the leading-edge to leading-edge convention. Paired t Tests were used for quantitative variables and McNemar-tests for qualitative variables. The mean age of patients was 56 ± 12 years, 54% were men, 38% received ß-blockers, and mean systolic and diastolic BP were 137 ± 25 and 78 ± 19 mm Hg. SoV diameters were significantly larger in ADPKD patients than in controls (36.4 ± 4.1 vs 34.0 ± 3.7 mm, p <0.0001). The Z-scores (normalized for sex, age, and body surface area) were significantly higher in ADPKD patients, both for SoV and tubular ascending aorta. Moreover, aortic aneurysms, as defined by a Z score >2 standard deviations, were present in 27 ADPKD patients (44%) versus 9 controls (15%, p <0.001). In conclusion, there is an increased prevalence of aortic aneurysms in ADPKD patients as compared with controls matched for common confounding factors for aortic dilation.

Left Ventricular Torsion Associated With Aortic Stiffness in Hypertension.

BACKGROUND: Left ventricular (LV) torsion plays a key role in cardiac efficiency. In hypertension, aortic stiffening augments cardiac afterload. However, little is known about the links between LV regional contraction and aortic stiffness. We, therefore, investigated these relationships and their contribution to LV diastolic function. METHODS AND RESULTS: The study included normotensive and hypertensive individuals with normal LV ejection. Apical, basal, and global LV rotation rate and LV global longitudinal strain were measured (2-dimensional speckle tracking echocardiography). Aortic stiffness was calculated from carotid-femoral pulse wave velocity, and LV relaxation was calculated from early diastolic mitral annulus motion. The ratio of basal or apical untwist/twist rates was calculated to assess relationships between aortic stiffness and LV torsion parameters. LV twist and untwist rates were greater in hypertensive than normotensive individuals because of increased basal twist (P<0.001) and untwist (P<0.001) rates. LV relaxation was reduced (early diastolic mitral annulus motion=7.4±1.9 versus 10.4±2.3 cm/s; P<0.001). In the whole population, basal untwist rate increased with aortic stiffening (R=0.43; P<0.001) and LV relaxation (R=0.41; P=0.001). The ratio of basal untwist/twist rate was positively correlated with carotid-femoral pulse wave velocity, and in the hypertensive group, was greater than in the control group and positively correlated to carotid-femoral pulse wave velocity(P<0.001). Results were independent of age, treatment, mean blood pressure, and indexed LV mass. CONCLUSIONS: In hypertensive individuals, greater basal LV torsion was associated with increased aortic stiffness and improved diastolic function. These changes may compensate for the deleterious effects of aortic stiffening on LV relaxation.

High-sensitivity cardiac troponin T is a biomarker for atherosclerosis in systemic lupus erythematous patients: a cross-sectional controlled study.

BACKGROUND: Cardiovascular disease (CVD) is the main cause of death in systemic lupus erythematous (SLE) patients. The Framingham score underestimates the risk for CVD in this population. Our study aimed to determine whether serum high-sensitivity cardiac troponin T (HS-cTnT) might help to identify SLE patients at risk for CVD. METHODS: The presence of carotid plaques was prospectively assessed by ultrasound in 63 consecutive SLE patients asymptomatic for CVD and 18 controls. Serum HS-cTnT concentration was measured using the electrochemiluminescence method. Factors associated with carotid plaques were identified and multivariate analysis was performed. RESULTS: Framingham score was low in both SLE patients (median 1 (range 1-18%)) and controls (1 (1-13%)). Nevertheless, 23 (36.5%) SLE patients, but only 2 (11.1%) controls (p = 0.039), had carotid plaque detected by vascular ultrasound. In the multivariate analysis, only age (p = 0.006) and SLE status (p = 0.017) were independently associated with carotid plaques. Serum HS-cTnT concentration was detectable (i.e. >3 ng/L) in 37 (58.7%) SLE patients and 6 (33.3%) controls (p = 0.057). Interestingly, 87% of SLE patients with carotid plaques, but only 42.5% of SLE patients without plaques (p < 0.001), had detectable HS-cTnT. Conversely, 54.5% of SLE patients with detectable HS-cTnT, but only 11.5% with undetectable HS-cTnT (p < 0.001), had a carotid plaque. In the multivariate analysis, only body mass index (p = 0.006) and HS-cTnT (p = 0.033) were statistically associated with carotid plaques in SLE patients. Overall, the risk of having a carotid plaque was increased by 9 (odds ratio 9.26, 95% confidence interval 1.55-90.07) in SLE patients in whom HS-cTnT was detectable in serum. CONCLUSION: Serum HS-cTnT level is high and associated with carotid plaques in SLE patients who are at an apparently low risk for CVD according to the Framingham score. HS-cTnT may be a useful biomarker for SLE-associated atherosclerosis.

High mass (>18g) of late gadolinium enhancement on CMR imaging is associated with major cardiac events on long-term outcome in patients with biopsy-proven extracardiac sarcoidosis.

BACKGROUND: Cardiac involvement is the most important cause of mortality in patients with systemic sarcoidosis. Late gadolinium enhancement (LGE) on cardiovascular magnetic resonance imaging (CMR) has been shown to be a predictor of major cardiovascular adverse events (MACE) in the setting of systemic sarcoidosis. We sought to evaluate the relationship between LGE mass and adverse long-term outcome in patients with biopsy-proven extracardiac sarcoidosis. METHODS: Between 2001 and 2013, 197 consecutive patients with suspected cardiac sarcoidosis were identified in our institution database. Of them, 56 patients have had biopsy-proven extracardiac sarcoidosis and represented our studied population. Patients were divided into two groups based on LGE mass by a median value (mild LGE<18g, high LGE>18g) for comparison of MACE. RESULTS: Twenty-eight patients had a high mass of LGE. Of them, 15 (54%) experienced MACE (OR=31.15, 95% CI 3.7-262). Except for 1 patient, no patient with mild LGE presented with any MACE during follow-up (median of 32months). Patients with high LGE had lower CMR-derived left (53.6±14.9 vs. 62.2±6.7, p<0.01) and right (49.1±11.5 vs. 56.4±9.2, p<0.05) ventricular ejection fractions. LGE mass of 18g discriminated patients with and without MACE (93% sensitivity, 88% specificity, AUC=0.972). LGE mass was the only independent predictor of MACE on multivariate Cox analysis adjusted (OR=1.7, 95% CI 1.06 to 2.72, p=0.03). CONCLUSION: In biopsy-proven extracardiac sarcoidosis patients, a high mass of LGE >18g was associated with MACE.

Overweight Is a Major Contributor to Atherosclerosis in Systemic Lupus Erythematosus Patients at Apparent Low Risk for Cardiovascular Disease: A Cross-Sectional Controlled Study.

Cardiovascular disease (CVD) is the main cause of death in systemic lupus erythematosus (SLE) patients. We aimed to determine whether overweight (defined as a body mass index [BMI] > 25 kg/m(2)) contributed to subclinical atherosclerosis in SLE patients at low risk for CVD according to traditional factors. Wall thickness of the internal carotid artery (ICWT) measured at the carotid bulb and carotid plaques were assessed in 49 SLE patients asymptomatic for CVD and 49 controls matched on Framingham score. Factors associated to ICWT were identified and multivariate analysis was performed.SLE patients and controls displayed a low 10-year risk for CVD according to Framingham score (mean 1.9 ± 3.5 in SLE vs 1.8 ± 3.2% in controls, P = 0.37). ICWT (P < 0.001) and number of patients with carotid plaques (P = 0.015) were, however, higher in SLE patients as compared to controls. In multivariable analysis, SLE was an independent risk for a carotid atherosclerosis (OR [95% confidence interval, CI]: 3.53 [1.36-9.14]; P = 0.009). Older age, higher BMI, and higher Framingham score were associated with atherosclerosis in SLE patients in univariate analysis. In multivariate analysis, only the association with overweight remained significant (OR [95% CI]: 4.13 [1.02-16.75]; P = 0.047). Overweight is a major contributor to atherosclerosis in SLE patients at apparent low risk for CVD.

CD4+CXCR3+ T cells and plasmacytoid dendritic cells drive accelerated atherosclerosis associated with systemic lupus erythematosus.

Cardiovascular disease due to accelerated atherosclerosis is the leading cause of death in patients with systemic lupus erythematosus (SLE). Noteworthy, accelerated atherosclerosis in SLE patients appears to be independant of classical Framingham risk factors. This suggests that aggravated atherosclerosis in SLE patients may be a result of increased inflammation and altered immune responses. However, the mechanisms that mediate the acceleration of atherosclerosis in SLE remain elusive. Based on experimental data which includes both humans (SLE patients and control subjects) and rodents (ApoE-/- mice), we herein propose a multi-step model in which the immune dysfunction associated with SLE (i.e. high level of IFN-α production by TLR 9-stimulated pDCs) is associated with, first, an increased frequency of circulating pro inflammatory CD4+CXCR3+ T cells; second, an increased production of CXCR3 ligands by endothelial cells; third, an increased recruitment of pro-inflammatory CD4+CXCR3+ T cells into the arterial wall, and fourth, the development of atherosclerosis. In showing how SLE may promote accelerated atherosclerosis, our model also points to hypotheses for potential interventions, such as pDCs-targeted therapy, that might be studied in the future.

Topical Mineralocorticoid Receptor Blockade Limits Glucocorticoid-Induced Epidermal Atrophy in Human Skin.

A major deleterious side effect of glucocorticoids is skin atrophy. Glucocorticoids activate the glucocorticoid and the mineralocorticoid (MR) receptor, both present in the epidermis. We hypothesized that glucocorticoid-induced epidermal atrophy may be related to inappropriate occupancy of MR by glucocorticoids. We evaluated whether epidermal atrophy induced by the topical glucocorticoid clobetasol could be limited by coadministration of MR antagonist. In cultured human skin explants, the epidermal atrophy induced by clobetasol was significantly limited by MR antagonism (canrenoate and eplerenone). Blockade of the epithelial sodium channel ENaC by phenamil was also efficient, identifying a role of MR-ENaC cascade in keratinocytes, acting through restoration of clobetasol-induced impairment of keratinocyte proliferation. In the SPIREPI randomized double-blind controlled trial, gels containing clobetasol, the MR antagonist spironolactone, both agents, or placebo were applied on four zones of the forearms of 23 healthy volunteers for 28 days. Primary outcome was histological thickness of the epidermis with clobetasol alone or clobetasol+spironolactone. Spironolactone alone did not affect the epidermal thickness but coapplication of clobetasol and spironolactone significantly limited clobetasol-induced atrophy and was well tolerated. Altogether, these findings identify MR as a factor regulating epidermal homeostasis and suggest that topical MR blockade could limit glucocorticoid-induced epidermal atrophy.

Activation of the hypothalamic-pituitary-adrenal axis in adults with mineralocorticoid receptor haploinsufficiency.

CONTEXT: Mineralocorticoid receptors (MRs) contribute to the negative feedback of the hypothalamic-pituitary-adrenal (HPA) axis in rodents. Studies with MR antagonists suggest a similar role in humans. OBJECTIVE: The objective of the study was to establish whether loss-of-function mutations in NR3C2, encoding MR, cause activation of the HPA axis. DESIGN AND SETTING: This was a case-control study in members of pedigrees from the PHA1.NET cohort, comprising patients with pseudohypoaldosteronism type 1 (PHA1) who are heterozygous for loss-of-function mutations in NR3C2 and healthy controls who are unaffected family members. PARTICIPANTS: Twelve adult patients with PHA1 (six men, six women) and 20 age-matched healthy controls (seven men, 13 women) participated in the study. RESULTS: Patients with PHA1 had higher morning plasma cortisol (816 ± 85 vs 586 ± 50 nmol/L, P = .02) and increased 24-hour urinary excretion of cortisol metabolites (985 ± 150 vs 640 ± 46 µg/mmol creatinine, P = .03), independently of gender. After adjustment for gender, age, PHA1 diagnosis, and percentage body fat, higher plasma cortisol was associated with higher plasma renin, lower serum high-density lipoprotein-cholesterol, and higher waist circumference but not with blood pressure, carotid intima-media thickness, or echocardiographic parameters. CONCLUSIONS: Haploinsufficiency of MR in PHA1 causes HPA axis activation, providing genetic evidence that MR contributes to negative feedback in the human HPA axis. With limited sample size, initial indications suggest the resulting hypercortisolemia is related to the severity of MR deficiency and has adverse effects mediated by glucocorticoid receptors on liver lipid metabolism and adipose tissue distribution but does not adversely affect cardiac and vascular remodeling in the absence of normal signaling through the MR.

Epac contributes to cardiac hypertrophy and amyloidosis induced by radiotherapy but not fibrosis.

BACKGROUND: Cardiac toxicity is a side-effect of anti-cancer treatment including radiotherapy and this translational study was initiated to characterize radiation-induced cardiac side effects in a population of breast cancer patients and in experimental models in order to identify novel therapeutic target. METHODS: The size of the heart was evaluated in CO-HO-RT patients by measuring the Cardiac-Contact-Distance before and after radiotherapy (48months of follow-up). In parallel, fibrogenic signals were studied in a severe case of human radiation-induced pericarditis. Lastly, radiation-induced cardiac damage was studied in mice and in rat neonatal cardiac cardiomyocytes. RESULTS: In patients, time dependent enhancement of the CCD was measured suggesting occurrence of cardiac hypertrophy. In the case of human radiation-induced pericarditis, we measured the activation of fibrogenic (CTGF, RhoA) and remodeling (MMP2) signals. In irradiated mice, we documented decreased contractile function, enlargement of the ventricular cavity and long-term modification of the time constant of decay of Ca(2+) transients. Both hypertrophy and amyloid deposition were correlated with the induction of Epac-1; whereas radiation-induced fibrosis correlated with Rho/CTGF activation. Transactivation studies support Epac contribution in hypertrophy stimulation and showed that radiotherapy and Epac displayed specific and synergistic signals. CONCLUSION: Epac-1 has been identified as a novel regulator of radiation-induced hypertrophy and amyloidosis but not fibrosis in the heart.

Increased arterial stiffness in systemic lupus erythematosus (SLE) patients at low risk for cardiovascular disease: a cross-sectional controlled study.

Cardiovascular disease (CVD) is a major cause of death in systemic lupus erythematosus (SLE) patients. Although the risk for cardiovascular events in patients with SLE is significant, the absolute number of events per year in any given cohort remains small. Thus, CVD risks stratification in patients with SLE focuses on surrogate markers for atherosclerosis at an early stage, such as reduced elasticity of arteries. Our study was designed to determine whether arterial stiffness is increased in SLE patients at low risk for CVD and analyze the role for traditional and non-traditional CVD risk factors on arterial stiffness in SLE. Carotid-femoral pulse wave velocity (PWV) was prospectively assessed as a measure of arterial stiffness in 41 SLE patients and 35 controls (CTL). Adjustment on age or Framingham score was performed using a logistic regression model. Factors associated with PWV were identified separately in SLE patients and in controls using Pearson's correlation coefficient for univariate analysis and multiple linear regression for multivariate analysis. SLE patients and controls displayed a low 10-year risk for CVD according to Framingham score (1.8±3.6% in SLE vs 1.6±2.8% in CTL, p = 0.46). Pulse wave velocity was, however, higher in SLE patients (7.1±1.6 m/s) as compared to controls (6.3±0.8 m/s; p = 0.01, after Framingham score adjustment) and correlated with internal carotid wall thickness (p = 0.0017). In multivariable analysis, only systolic blood pressure (p = 0.0005) and cumulative dose of glucocorticoids (p = 0.01) were associated with PWV in SLE patients. Interestingly, the link between systolic blood pressure (SBP) and arterial stiffness was also confirmed in SLE patients with normal systolic blood pressure. In conclusion, arterial stiffness is increased in SLE patients despite a low risk for CVD according to Framingham score and is associated with systolic blood pressure and glucocorticoid therapy.

Aortic arch atheroma in transient ischemic attack patients.

OBJECTIVE: Aortic arch atheroma (AAA) is associated with vascular risk factors and with stroke risk. Its prevalence and prognosis remain to be defined in patients with transient ischemic attack (TIA). METHODS: Using data from the SOS-TIA registry, we assessed the prevalence of AAA detected by transesophageal echocardiography (TEE). AAA was graded as moderate (<4 mm) or severe (≥4 mm). All patients had a standardized work-up investigation and were followed for 1 year. RESULTS: Between January 2003 and December 2008, 1850 patients with definite/possible TIA or minor stroke were enrolled and 1231 (67%) underwent TEE. Moderate AAA was found in 26% of patients (n = 324) and severe AAA in 14% (n = 171), giving an overall AAA prevalence of 40%. Among the 873 patients without identified cause of TIA, the prevalence of moderate and severe AAA were 24% and 12% respectively. Intracranial or extracranial stenosis ≥50% were detected in 21% of patients and were independently associated with AAA (adjusted odds ratio, 1.65, 95% confidence interval (CI), 1.23-2.22). At one-year, incidence of recurrent vascular events was 2.2% in patients without AAA, 4.1% in moderate AAA and 6.6% in severe AAA (log-rank, p for trend = 0.003). Using patients without AAA as reference, and after adjustment on vascular risk factors, the hazard ratio (95% CI) for moderate was 1.36 (0.62-2.99) and 2.08 (0.89-4.86) for severe (p for trend = 0.095). CONCLUSIONS: These findings support a systematic identification of AAA in TIA patients to optimize risk stratification in this specific population.

Potassium channel openers increase aortic elastic fiber formation and reverse the genetically determined elastin deficit in the BN rat.

Hypertension is a cardiovascular disorder that appears in more than half of the patients with Williams-Beuren syndrome, hemizygous for the elastin gene among 26 to 28 other genes. It was shown that the antihypertensive drug minoxidil, an ATP-dependent potassium channel opener, enhances elastic fiber formation; however, no wide clinical application was developed because of its adverse side effects. The Brown Norway rat was used here as an arterial elastin-deficient model. We tested 3 different potassium channel openers, minoxidil, diazoxide, and pinacidil, and 1 potassium channel blocker, glibenclamide, on cultured smooth muscle cells from Brown Norway rat aorta. All tested potassium channel openers increased mRNAs encoding proteins and enzymes involved in elastic fiber formation, whereas glibenclamide had the opposite effect. The higher steady-state level of tropoelastin mRNA in minoxidil-treated cells was attributable to an increase in both transcription and mRNA stability. Treatment of Brown Norway rats for 10 weeks with minoxidil or diazoxide increased elastic fiber content and decreased cell number in the aortic media, without changing collagen content. The minoxidil-induced cardiac hypertrophy was reduced when animals simultaneously received irbesartan, an angiotensin II-receptor antagonist. This side effect of minoxidil was not observed in diazoxide-treated animals. In conclusion, diazoxide, causing less undesirable side effects than minoxidil, or coadministration of minoxidil and irbesartan, increases elastic fiber content, decreases cell number in the aorta and, thus, could be suitable for treating vascular pathologies characterized by diminished arterial elastin content and simultaneous hypertension.

Cardiovascular effects of aldosterone: insight from adult carriers of mineralocorticoid receptor mutations.

BACKGROUND: High plasma aldosterone has deleterious cardiovascular effects that are independent of blood pressure, but the role of the mineralocorticoid receptor remains unclear. Renal pseudohypoaldosteronism type 1 is a rare autosomal-dominant disease caused by NR3C2 loss-of-function mutations, which is characterized by renal salt loss and compensatory high renin and aldo secretion. We aimed to assess the cardiovascular outcomes in adults carrying NR3C2 mutations. METHODS AND RESULTS: In this case-control study, 39 NR3C2 mutation carriers were compared with sex- and age-paired noncarriers. Patients underwent cardiac and vascular ultrasound, cardiac MRI with gadolinium injection, measurement of pulse wave velocity, extracellular water, 24-hour ambulatory blood pressure, and autonomous nervous system activity. Mutation carriers showed increased aldo and renin plasma levels (4.5- and 1.6-fold, respectively; P<0.0001), together with increased salt appetite (1.8-fold; P=0.002), with normal extracellular water and blood pressure, and no autonomous nervous system activation. Cardiac and vascular parameters were not significantly different between mutation carriers and noncarriers (no left ventricular remodeling or fibrosis, normal left ventricular systolic function, and aorta stiffness). Tissue Doppler showed better diastolic left ventricular function in mutation carriers (e', P=0.001; E/e', P=0.003). Mutation carriers had significantly more frequent history of slow body weight recovery at birth, symptomatic hypotension, and miscarriage in women. CONCLUSIONS: Despite life-long increase in plasma aldosterone and renin levels, no adverse cardiovascular outcome occurred in pseudohypoaldosteronism type 1, but rather an improved diastolic left ventricular function. This suggests that the cardiovascular consequences of aldosterone excess require full mineralocorticoid receptor signaling. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov; unique identifier: NCT00646828.

Enhanced sensitivity to low dose irradiation of ApoE-/- mice mediated by early pro-inflammatory profile and delayed activation of the TGFß1 cascade involved in fibrogenesis.

AIM: Investigating long-term cardiac effects of low doses of ionizing radiation is highly relevant in the context of interventional cardiology and radiotherapy. Epidemiological data report that low doses of irradiation to the heart can result in significant increase in the cardiovascular mortality by yet unknown mechanisms. In addition co-morbidity factor such as hypertension or/and atherosclerosis can enhance cardiac complications. Therefore, we explored the mechanisms that lead to long-term cardiac remodelling and investigated the interaction of radiation-induced damage to heart and cardiovascular systems with atherosclerosis, using wild-type and ApoE-deficient mice. METHODS AND RESULTS: ApoE-/- and wild-type mice were locally irradiated to the heart at 0, 0.2 and 2 Gy (RX). Twenty, 40 and 60 weeks post-irradiation, echocardiography were performed and hearts were collected for cardiomyocyte isolation, histopathological analysis, study of inflammatory infiltration and fibrosis deposition. Common and strain-specific pathogenic pathways were found. Significant alteration of left ventricular function (eccentric hypertrophy) occurred in both strains of mice. Low dose irradiation (0.2 Gy) induced premature death in ApoE-/- mice (47% died at 20 weeks). Acute inflammatory infiltrate was observed in scarring areas with accumulation of M1-macrophages and secretion of IL-6. Increased expression of the fibrogenic factors (TGF-ß1 and PAI-1) was measured earlier in cardiomyocytes isolated from ApoE-/- than in wt animals. CONCLUSION: The present study shows that cardiac exposure to low dose of ionizing radiation induce significant physiological, histopathological, cellular and molecular alterations in irradiated heart with mild functional impairment. Atherosclerotic predisposition precipitated cardiac damage induced by low doses with an early pro-inflammatory polarization of macrophages.

An SRF/miR-1 axis regulates NCX1 and annexin A5 protein levels in the normal and failing heart.

AIMS: The expression of the sodium/calcium exchanger NCX1 increases during cardiac hypertrophy and heart failure, playing an important role in Ca(2+) extrusion. This increase is presumed to result from stress signalling induced changes in the interplay between transcriptional and post-transcriptional regulations. We aimed to determine the impact of the SRF transcription factor known to regulate the NCX1 promoter and microRNA genes, on the expression of NCX1 mRNA and protein and annexin A5 (AnxA5), a Ca(2+)-binding protein interacting with NCX1 and increased during HF. METHODS AND RESULTS: NCX1 mRNA was decreased while the protein was increased in the failing heart of the cardiomyocyte-restricted SRF knock-out mice (SRF(HKO)). The induction of NCX1 mRNA by the pro-hypertrophic drug phenylephrine observed in control mice was abolished in the SRF(HKO) though the protein was strongly increased. AnxA5 protein expression profile paralleled the expression of NCX1 protein in the SRF(HKO). MiR-1, a microRNA regulated by SRF, was decreased in the SRF(HKO) and repressed by phenylephrine. In vitro and in vivo manipulation of miR-1 levels and site-directed mutagenesis showed that NCX1 and AnxA5 mRNAs are targets of miR-1. AnxA5 overexpression slowed down Ca(2+) extrusion during caffeine application in adult rat cardiomyocytes. CONCLUSION: Our study reveals the existence of a complex regulatory loop where SRF regulates the transcription of NCX1 and miR-1, which in turn functions as a rheostat limiting the translation of NCX1 and AnxA5 proteins. The decrease of miR-1 and increase of AnxA5 appear as important modulators of NCX1 expression and activity during heart failure.

Epo deficiency alters cardiac adaptation to chronic hypoxia.

The involvement of erythropoietin in cardiac adaptation to acute and chronic (CHx) hypoxia was investigated in erythropoietin deficient transgenic (Epo-TAg(h)) and wild-type (WT) mice. Left (LV) and right ventricular functions were assessed by echocardiography and hemodynamics. HIF-1α, VEGF and Epo pathways were explored through RT-PCR, ELISA, Western blot and immunocytochemistry. Epo gene and protein were expressed in cardiomyocytes of WT mice in normoxia and hypoxia. Increase in blood hemoglobin, angiogenesis and functional cardiac adaptation occurred in CHx in WT mice, allowing a normal oxygen delivery (O2T). Epo deficiency induced LV hypertrophy, increased cardiac output (CO) and angiogenesis, but O2T remained lower than in WT mice. In CHx Epo-TAg(h) mice, LV hypertrophy, CO and O2T decreased. HIF-1α and Epo receptor pathways were depressed, suggesting that Epo-TAg(h) mice could not adapt to CHx despite activation of cardioprotective pathways (increased P-STAT-5/STAT-5). HIF/Epo pathway is activated in the heart of WT mice in hypoxia. Chronic hypoxia induced cardiac adaptive responses that were altered with Epo deficiency, failing to maintain oxygen delivery to tissues.