Deficiency of heme oxygenase 1a causes detrimental effects on cardiac function.

Humans lacking heme oxygenase 1 (HMOX1) display growth retardation, haemolytic anaemia, and vulnerability to stress; however, cardiac function remains unclear. We aimed to explore the cardiac function of zebrafish lacking hmox1a at baseline and in response to stress. We generated zebrafish hmox1a mutants using CRISPR/Cas9 genome editing technology. Deletion of hmox1a increases cardiac output and further induces hypertrophy in adults. Adults lacking hmox1a develop myocardial interstitial fibrosis, restrain cardiomyocyte proliferation and downregulate renal haemoglobin and cardiac antioxidative genes. Larvae lacking hmox1a fail to respond to hypoxia, whereas adults are insensitive to isoproterenol stimulation in the heart, suggesting that hmox1a is necessary for cardiac response to stress. Haplodeficiency of hmox1a stimulates non-mitochondrial respiration and cardiac cell proliferation, increases cardiac output in larvae in response to hypoxia, and deteriorates cardiac function and structure in adults upon isoproterenol treatment. Intriguingly, haplodeficiency of hmox1a upregulates cardiac hmox1a and hmox1b in response to isoproterenol. Collectively, deletion of hmox1a results in cardiac remodelling and abrogates cardiac response to hypoxia and isoproterenol. Haplodeficiency of hmox1a aggravates cardiac response to the stress, which could be associated with the upregulation of hmox1a and hmox1b. Our data suggests that HMOX1 homeostasis is essential for maintaining cardiac function and promoting cardioprotective effects.

MiR-185-5p regulates the development of myocardial fibrosis.

BACKGROUND: Cardiac fibrosis stiffens the ventricular wall, predisposes to cardiac arrhythmias and contributes to the development of heart failure. In the present study, our aim was to identify novel miRNAs that regulate the development of cardiac fibrosis and could serve as potential therapeutic targets for myocardial fibrosis. METHODS AND RESULTS: Analysis for cardiac samples from sudden cardiac death victims with extensive myocardial fibrosis as the primary cause of death identified dysregulation of miR-185-5p. Analysis of resident cardiac cells from mice subjected to experimental cardiac fibrosis model showed induction of miR-185-5p expression specifically in cardiac fibroblasts. In vitro, augmenting miR-185-5p induced collagen production and profibrotic activation in cardiac fibroblasts, whereas inhibition of miR-185-5p attenuated collagen production. In vivo, targeting miR-185-5p in mice abolished pressure overload induced cardiac interstitial fibrosis. Mechanistically, miR-185-5p targets apelin receptor and inhibits the anti-fibrotic effects of apelin. Finally, analysis of left ventricular tissue from patients with severe cardiomyopathy showed an increase in miR-185-5p expression together with pro-fibrotic TGF-ß1 and collagen I. CONCLUSIONS: Our data show that miR-185-5p targets apelin receptor and promotes myocardial fibrosis.

Tankyrase Inhibition Attenuates Cardiac Dilatation and Dysfunction in Ischemic Heart Failure.

Hyperactive poly(ADP-ribose) polymerases (PARP) promote ischemic heart failure (IHF) after myocardial infarction (MI). However, the role of tankyrases (TNKSs), members of the PARP family, in pathogenesis of IHF remains unknown. We investigated the expression and activation of TNKSs in myocardium of IHF patients and MI rats. We explored the cardioprotective effect of TNKS inhibition in an isoproterenol-induced zebrafish HF model. In IHF patients, we observed elevated TNKS2 and DICER and concomitant upregulation of miR-34a-5p and miR-21-5p in non-infarcted myocardium. In a rat MI model, we found augmented TNKS2 and DICER in the border and infarct areas at the early stage of post-MI. We also observed consistently increased TNKS1 in the border and infarct areas and destabilized AXIN in the infarct area from 4 weeks onward, which in turn triggered Wnt/ß-catenin signaling. In an isoproterenol-induced HF zebrafish model, inhibition of TNKS activity with XAV939, a TNKSs-specific inhibitor, protected against ventricular dilatation and cardiac dysfunction and abrogated overactivation of Wnt/ß-catenin signaling and dysregulation of miR-34a-5p induced by isoproterenol. Our study unravels a potential role of TNKSs in the pathogenesis of IHF by regulating Wnt/ß-catenin signaling and possibly modulating miRNAs and highlights the pharmacotherapeutic potential of TNKS inhibition for prevention of IHF.

Unfavorable Reduction in the Ratio of Endothelin B to A Receptors in Experimental 5/6 Nephrectomy and Adenine Models of Chronic Renal Insufficiency.

Chronic renal insufficiency (CRI) is characterized by increased endothelin 1 (ET-1) synthesis. We studied rat kidney endothelin receptor A (ETA) and receptor B (ETB) expressions after 12 and 27 weeks of 5/6 nephrectomy, and after 12 weeks of 0.3% adenine diet, representing proteinuric and interstitial inflammation models of CRI, respectively. Uric acid and calcium-phosphate metabolism were modulated after 5/6 nephrectomy, while ETA blocker and calcimimetic were given with adenine. Endothelin receptor mRNA levels were measured using RT-qPCR and protein levels using autoradiography (5/6 nephrectomy) or ELISA (adenine model). Both 12 and 27 weeks after 5/6 nephrectomy, kidney cortex ETA protein was increased by ~60% without changes in ETB protein, and the ETB:ETA ratio was reduced. However, the ETB:ETA mRNA ratio did not change. In the adenine model, kidney ETA protein was reduced by ~70%, while ETB protein was suppressed by ~95%, and the ETB:ETA ratio was reduced by ~85%, both at the protein and mRNA levels. The additional interventions did not influence the observed reductions in the ETB:ETA ratio. To conclude, unfavorable reduction in the ETB:ETA protein ratio was observed in two different models of CRI. Therefore, ETA blockade may be beneficial in a range of diseases that cause impaired kidney function.

Association of miR-21-5p, miR-122-5p, and miR-320a-3p with 90-Day Mortality in Cardiogenic Shock.

Cardiogenic shock (CS) is a life-threatening emergency. New biomarkers are needed in order to detect patients at greater risk of adverse outcome. Our aim was to assess the characteristics of miR-21-5p, miR-122-5p, and miR-320a-3p in CS and evaluate the value of their expression levels in risk prediction. Circulating levels of miR-21-5p, miR-122-5p, and miR-320a-3p were measured from serial plasma samples of 179 patients during the first 5-10 days after detection of CS, derived from the CardShock study. Acute coronary syndrome was the most common cause (80%) of CS. Baseline (0 h) levels of miR-21-5p, miR-122-5p, and miR-320a-3p were all significantly elevated in nonsurvivors compared to survivors (p < 0.05 for all). Above median levels at 0h of each miRNA were each significantly associated with higher lactate and alanine aminotransferase levels and decreased glomerular filtration rates. After adjusting the multivariate regression analysis with established CS risk factors, miR-21-5p and miR-320a-3p levels above median at 0 h were independently associated with 90-day all-cause mortality (adjusted hazard ratio 1.8 (95% confidence interval 1.1-3.0), p = 0.018; adjusted hazard ratio 1.9 (95% confidence interval 1.2-3.2), p = 0.009, respectively). In conclusion, circulating plasma levels of miR-21-5p, miR-122-5p, and miR-320a-3p at baseline were all elevated in nonsurvivors of CS and associated with markers of hypoperfusion. Above median levels of miR-21-5p and miR-320a-3p at baseline appear to independently predict 90-day all-cause mortality. This indicates the potential of miRNAs as biomarkers for risk assessment in cardiogenic shock.

Pooled analysis of Phase III trials indicate contrasting influences of renal function on blood pressure, body weight, and HbA1c reductions with empagliflozin.

Sodium glucose cotransporter 2 (SGLT2) inhibitors reduce HbA1c, blood pressure, and weight in patients with type 2 diabetes. To investigate the effect of renal function on reductions in these parameters with the SGLT2 inhibitor empagliflozin, we assessed subgroups by baseline estimated glomerular filtration rate (eGFR; Modification of Diet in Renal Disease) in pooled data from five 24-week trials of 2286 patients with type 2 diabetes randomized to empagliflozin or placebo. Reductions in HbA1c with empagliflozin versus placebo significantly diminished with decreasing baseline eGFR. Reductions in systolic blood pressure (SBP) with empagliflozin were maintained in patients with lower eGFR. The mean placebo-corrected changes from baseline in systolic blood pressure at week 24 with empagliflozin were -3.2 (95% confidence interval -4.9,-1.5) mmHg, -4.0 (-5.4, -2.6) mmHg, -5.5 (-7.6, -3.4) mmHg, and -6.6 (-11.4, -1.8) mmHg in patients with an eGFR of 90 or more, 60 to 89, 30 to 59, and under 30 ml/min/1.73m2, respectively. Similar trends were observed for diastolic blood pressure. Weight loss with empagliflozin versus placebo tended to be attenuated in patients with a lower eGFR. Results were consistent in a 12-week ambulatory blood pressure monitoring trial in 823 patients with type 2 diabetes and hypertension. Thus, unlike HbA1c reductions, systolic blood pressure and weight reductions with empagliflozin are generally preserved in patients with chronic kidney disease.

Sept7b is required for the subcellular organization of cardiomyocytes and cardiac function in zebrafish.

Myofibrils made up of actin, myosin, and associated proteins generate the contractile force in muscle, and, consequently, mutations in these proteins may lead to heart failure. Septins are a conserved family of small GTPases that associate with actin filaments, microtubules, and cellular membranes. Despite the importance of septins in cytoskeleton organization, their role in cardiomyocyte organization and function is poorly characterized. Here, we show that septin 7 is expressed in both embryonic and adult zebrafish hearts and elucidate the physiological significance of sept7b, the zebrafish ortholog of human septin 7, in the heart in embryonic and larval zebrafish. Knockdown of sept7b reduced F-actin and α-cardiac actin expression in the heart and caused disorganization of actin filaments. Electron microscopy of sept7b-depleted larvae showed disorganization of heart myofibrils and partial detachment from Z-disks. Functional studies revealed that knockdown of sept7b leads to reduced ventricular dimensions, contractility, and cardiac output. Furthermore, we found that depletion of sept7b diminished the expression of retinaldehyde dehydrogenase 2, which catalyzes the synthesis of retinoic acid necessary for heart morphogenesis. We further observed that the sept7b and retinoic acid signaling pathways converge to regulate cardiac function. Together, these results specify an essential role for sept7b in the contractile function of the heart.NEW & NOTEWORTHY Knockdown of the zebrafish ortholog of human septin 7 (sept7b) destabilizes cardiac actin and reduces ventricular dimensions, contractility, and cardiac output in larval zebrafish, indicating that sept7b is essential for cardiac function. We further found that sept7b and retinoic acid signaling pathways converge to regulate cardiac function. These data prompt further studies defining the role of sept7b in cardiomyopathies.

Impact of empagliflozin on blood pressure in dipper and non-dipper patients with type 2 diabetes mellitus and hypertension.

In the EMPA-REG BP trial, empagliflozin significantly reduced systolic and diastolic blood pressure (SBP and DBP) compared with placebo at week 12 in patients with type 2 diabetes mellitus (T2DM) and hypertension. In a post-hoc analysis, we assessed the effect of empagliflozin on SBP and DBP using 24-hour ambulatory BP monitoring in patients categorized as dippers (sleep-time mean SBP ≤ 90% of awake-time mean; n = 417) or non-dippers (sleep-time mean SBP > 90% of awake-time mean; n = 350). In dippers, adjusted mean (SE) changes from baseline in mean 24-hour SBP (mm Hg) at week 12 were -0.2 (0.7) with placebo vs -3.8 (0.6) and -3.9 (0.7) with empagliflozin 10 and 25 mg, respectively (both P < .001 vs placebo). In non-dippers, these changes were 1.0 (0.7) with placebo vs -1.6 (0.7) with empagliflozin 10 mg ( P = .013 vs placebo) and -3.8 (0.7) with empagliflozin 25 mg ( P < .001 vs placebo). In both dippers and non-dippers, SBP and DBP patterns over 24 hours were maintained. There were no clinically relevant changes in heart rate with empagliflozin. In conclusion, empagliflozin significantly reduced mean 24-hour SBP compared with placebo in dippers and non-dippers.

Endothelin A receptor blocker and calcimimetic in the adenine rat model of chronic renal insufficiency.

BACKGROUND: We studied whether endothelin receptor antagonist and calcimimetic treatments influence renal damage and kidney renin-angiotensin (RA) components in adenine-induced chronic renal insufficiency (CRI). METHODS: Male Wistar rats (n = 80) were divided into 5 groups for 12 weeks: control (n = 12), 0.3% adenine (Ade; n = 20), Ade + 50 mg/kg/day sitaxentan (n = 16), Ade + 20 mg/kg/day cinacalcet (n = 16), and Ade + sitaxentan + cinacalcet (n = 16). Blood pressure (BP) was measured using tail-cuff, kidney histology was examined, and RA components measured using RT-qPCR. RESULTS: Adenine caused tubulointerstitial damage with severe CRI, anemia, hyperphosphatemia, 1.8-fold increase in urinary calcium excretion, and 3.5-fold and 18-fold increases in plasma creatinine and PTH, respectively. Sitaxentan alleviated tubular atrophy, while sitaxentan + cinacalcet combination reduced interstitial inflammation, tubular dilatation and atrophy in adenine-rats. Adenine diet did not influence kidney angiotensin converting enzyme (ACE) and AT4 receptor mRNA, but reduced mRNA of renin, AT1a, AT2, (pro)renin receptor and Mas to 40-60%, and suppressed ACE2 to 6% of that in controls. Sitaxentan reduced BP by 8 mmHg, creatinine, urea, and phosphate concentrations by 16-24%, and PTH by 42%. Cinacalcet did not influence BP or creatinine, but reduced PTH by 84%, and increased hemoglobin by 28% in adenine-rats. The treatments further reduced renin mRNA by 40%, while combined treatment normalized plasma PTH, urinary calcium, and increased ACE2 mRNA 2.5-fold versus the Ade group (p < 0.001). CONCLUSIONS: In adenine-induced interstitial nephritis, sitaxentan improved renal function and tubular atrophy. Sitaxentan and cinacalcet reduced kidney renin mRNA by 40%, while their combination alleviated tubulointerstitial damage and urinary calcium loss, and increased kidney tissue ACE2 mRNA.

The effects of baroreflex activation therapy on blood pressure and sympathetic function in patients with refractory hypertension: the rationale and design of the Nordic BAT study.

OBJECTIVE: To explore the effects of baroreflex activation therapy (BAT) on hypertension in patients with treatment resistant or refractory hypertension. METHODS: This investigator-initiated randomized, double-blind, 1:1 parallel-design clinical trial will include 100 patients with refractory hypertension from 6 tertiary referral hypertension centers in the Nordic countries. A Barostim Neo System will be implanted and after 1 month patients will be randomized to either BAT for 16 months or continuous pharmacotherapy (BAT off) for 8 months followed by BAT for 8 months. A second randomization will take place after 16 months to BAT or BAT off for 3 months. Eligible patients have a daytime systolic ambulatory blood pressure (ABPM) of ≥145 mm Hg, and/or a daytime diastolic ABPM of ≥95 mm Hg after witnessed drug intake (including ≥3 antihypertensive drugs, preferably including a diuretic). RESULTS: The primary end point is the reduction in 24-hour systolic ABPM by BAT at 8 months, as compared to pharmacotherapy. Secondary and tertiary endpoints are effects of BAT on home and office blood pressures, measures of indices of cardiac and vascular structure and function during follow-up, and safety. CONCLUSIONS: This academic initiative will increase the understanding of mechanisms and role of BAT in the refractory hypertension.

Postoperative Cardiac Ischemia Detection by Continuous 12-Lead Electrocardiographic Monitoring in Vascular Surgery Patients: A Prospective, Observational Study.

OBJECTIVES: Elderly patients undergoing vascular surgery are at major risk for perioperative cardiac complications. The authors investigated continuous electrocardiographic Holter monitoring in a postoperative setting to determine the degree of postoperative ischemic load and its possible associations with perioperative myocardial infarction. DESIGN: A prospective, observational study. SETTING: One university hospital. PARTICIPANTS: The study comprised 51 patients aged 65 years or older undergoing peripheral arterial surgery. INTERVENTIONS: Continuous electrocardiographic monitoring with a Holter device was started postoperatively and continued for 72 hours or until discharge. Postural changes were recorded using a 3-axis accelerometer. Standard 12-lead electrocardiography, high-sensitive troponin T measurements, and an inquiry of ischemic symptoms were performed 4 times perioperatively. MEASUREMENTS AND MAIN RESULTS: The primary outcomes were ischemic load (area under the function of ischemic ST-segment deviation and ischemic time) and perioperative myocardial infarction. During 3,262.7 patient-hours of monitoring, 17 patients (33.3%) experienced 608 transient ischemic events, all denoted by ST-segment depression. Of these 17 patients, 5 experienced perioperative myocardial infarction. The mean ischemic load in all patients was 913.2±2,797.3 µV×minute. Ischemic load predicted perioperative myocardial infarction, with an area under receiver operating characteristics curve (95% confidence interval) of 0.87 (0.75-0.99). Ischemic changes occurred most frequently during hours 24 to 60 of monitoring. Ischemia was asymptomatic in 14 of 17 patients (82.4%). CONCLUSION: Postoperative myocardial ischemia was common in peripheral vascular surgery patients and may progress to perioperative myocardial infarction. Ischemic load was a good predictor of perioperative myocardial infarction. Ambulatory electrocardiographic monitoring solutions for continuous postoperative ischemia detection are warranted in the surgical ward.

Potential role of sodium glucose cotransporter 2 inhibitors in the treatment of hypertension.

PURPOSE OF REVIEW: The majority of patients with type 2 diabetes mellitus (T2DM) have hypertension requiring combination therapy. Sodium glucose cotransporter 2 (SGLT2) inhibitors are novel glucose-lowering drugs with shared and potentially unique beneficial effects on cardiovascular risk beyond glycemic control. This review focuses on the potential role of SGLT2 inhibitors in the treatment of hypertension associated with T2DM. RECENT FINDINGS: SGLT2 inhibitors reduce office SBP by 3-5 mmHg and DBP by 2-3 mmHg across all class members. Corresponding clinically meaningful, significant blood pressure (BP) lowering effects have been confirmed using 24 h ambulatory BP monitoring. SGLT2 inhibitors reduce BP irrespective of the type of background antihypertensive medication. The antihypertensive actions of SGLT2 inhibitors involve several mechanisms including modest diuretic effects, weight loss, and direct vascular effects leading to decreased arterial stiffness and vascular resistance. The first-in class cardiovascular outcome trial with empagliflozin showed a significant reduction in a composite endpoint of cardiovascular death, nonfatal stroke, and nonfatal myocardial infarction in T2DM patients at high risk for cardiovascular events. SUMMARY: SGLT2 inhibitors have clinically significant antihypertensive effects. SGLT2 inhibition could be a potentially useful supplement to the BP-lowering treatment armamentarium in patients with T2DM.

Baroreflex activation therapy in the treatment of resistant hypertension.

Baroreceptors are sensory nerve endings in the carotid sinuses and the aortic arch. Notably, a dysfunction in the autonomic nervous system (sympathetic hyperactivity) has been shown to be part of the pathophysiology of chronic hypertension. Baroreflex activation therapy is an invasive treatment modality to decrease blood pressure by stimulating baroreceptors in the wall of the carotid sinus. Preliminary results of baroreflex activation therapy in resistant hypertension and systolic heart failure have been promising. If its effect can be proven in controlled studies, it may serve as an important new tool in the treatment of patients with resistant hypertension at a high risk of cardiovascular complications.

Vasopeptidase Inhibition Corrects the Structure and Function of the Small Arteries in Experimental Renal Insufficiency.

BACKGROUND: We studied whether vasopeptidase inhibition corrects the structure and function of the small arteries in experimental chronic renal insufficiency (CRI). METHODS: After 5/6 nephrectomy (NX) surgery was performed on rats, there was a 14-week follow-up, allowing CRI to become established. Omapatrilat (40 mg/kg/day in chow) was then given for 8 weeks, and the small mesenteric arterial rings were investigated in vitro using wire and pressure myographs. RESULTS: Plasma and ventricular B-type natriuretic peptide (BNP) concentrations were increased 2- to 2.7-fold, while systolic blood pressure (BP) increased by 32 mm Hg after NX. Omapatrilat treatment normalized the BNP and reduced the BP by 45 mm Hg in the NX rats. Endothelium-dependent vasorelaxation was impaired but the response to acetylcholine was normalized after omapatrilat treatment. Vasorelaxations induced by nitroprusside, isoprenaline and levcromakalim were enhanced after omapatrilat, and the responses were even more pronounced than in untreated sham-operated rats. Arterial wall thickness and wall-to-lumen ratio were increased after NX, whereas omapatrilat normalized these structural features and improved the strain-stress relationship in the small arteries; this suggests improved arterial elastic properties. CONCLUSION: Omapatrilat treatment reduced BP, normalized volume overload, improved vasorelaxation and corrected the dimensions and passive elastic properties of the small arteries in the NX rats. Therefore, we consider vasopeptidase inhibition to be an effective treatment for CRI-induced changes in the small arteries.

Phosphate binding reduces aortic angiotensin-converting enzyme and enhances nitric oxide bioactivity in experimental renal insufficiency.

BACKGROUND: Disturbed calcium-phosphorus metabolism is associated with increased kidney angiotensin-converting enzyme (ACE) in experimental chronic renal insufficiency (CRI). However, information about the effects of phosphate binding and loading on vascular ACE is lacking. METHODS: Fifteen weeks after 5/6 nephrectomy (NX), rats were placed on a phosphate-binding (NX+Ca, 3.0% Ca), phosphate-loading (NX+Pi, 1.5% Pi), or control diet for 12 weeks (NX and sham). RESULTS: Aortic ACE, blood pressure, plasma phosphate, and parathyroid hormone were increased in the NX and NX+Pi groups, but were reduced with phosphate binding. Endothelium-mediated relaxations of isolated mesenteric conduit artery rings to acetylcholine were impaired in the NX and NX+Pi groups, but did not differ from sham in NX+Ca rats. Experiments with nitric oxide (NO) synthase inhibition in vitro suggested that the NO-mediated component of acetylcholine response was lower in the NX and NX+Pi groups, but did not differ from sham in NX+Ca rats. In all NX groups, aortic endothelial NO synthase (eNOS) was reduced, while plasma and urine concentrations of NO metabolites were increased. Aortic nitrated proteins and calcification were increased in the NX and NX+Pi groups when compared with the NX+Ca and sham groups. CONCLUSION: Hypertension in the NX model of CRI was associated with reduced vasorelaxation, decreased eNOS, and increased ACE and nitrated proteins in the aorta. Phosphate binding with calcium carbonate enhanced vasorelaxation via endogenous NO and suppressed elevation of ACE and nitrated proteins, suggesting reduced vascular oxidative stress. Our findings support the view that correction of the calcium-phosphorus balance prevents CRI-induced vascular pathophysiology.

[Renal denervation in the treatment of hypertension]. / Munuaisten denervaatio hypertension hoidossa.

Therapy resistant hypertension is common in hypertensive patients. The kidneys play an important role in the sympathetic nervous system overactivity associated with hypertension. Percutaneous transluminal ablation of renal nerves is a novel treatment strategy for resistant hypertension decreasing both renal and systemic sympathetic activity. Renal denervation resulted in significant blood pressure reduction within 6 months in a multicentre, prospective, randomized trial. The treatment has proved safe and blood pressure reduction appears sustained up to 2 years. It also improves glycemic control. Further studies are needed to evaluate the mortality and morbidity impact of this promising therapy of resistant hypertension.

Moderate hyperuricaemia ameliorated kidney damage in a low-renin model of experimental renal insufficiency.

Uric acid has promoted renal fibrosis and inflammation in experimental studies, but some studies have shown nephroprotective effects due to alleviated oxidative stress. We studied the influence of experimental hyperuricaemia in surgically 5/6 nephrectomized rats. Three weeks after subtotal nephrectomy or sham operation, the rats were allocated to control diet or 2.0% oxonic acid (uricase inhibitor) diet for 9 weeks. Then blood, urine and tissue samples were taken, and renal morphology and oxidative stress were examined. Inflammation and fibrosis were evaluated using immunohistochemistry and real-time PCR (RT-PCR). Remnant kidney rats ingesting normal or oxonic acid diet presented with ~60% reduction of creatinine clearance and suppressed plasma renin activity. Oxonic acid diet increased plasma uric acid levels by >80 µmol/L. In remnant kidney rats, moderate hyperuricaemia decreased glomerulosclerosis, tubulointerstitial damage and kidney mast cell count, without influencing the fibrosis marker collagen I messenger RNA (mRNA) content. In both sham-operated and 5/6 nephrectomized rats, the mast cell product 11-epi-prostaglandin-F2α excretion to the urine and kidney tissue cyclooxygenase-2 (COX-2) levels were decreased. To conclude, hyperuricaemic remnant kidney rats displayed improved kidney morphology and reduced markers of oxidative stress and inflammation. Thus, moderately elevated plasma uric acid had beneficial effects on the kidney in this low-renin model of experimental renal insufficiency.

Dietary phosphate binding and loading alter kidney angiotensin-converting enzyme mRNA and protein content in 5/6 nephrectomized rats.

BACKGROUND: Vitamin D receptor activation with paricalcitol can modulate the transcription of renin-angiotensin system components in the surgical 5/6 nephrectomy rat model (5/6 NX) of chronic renal insufficiency. We tested the hypothesis whether dietary modification of phosphate influences kidney renin-angiotensin system gene expression at the mRNA level in 5/6 NX rats. METHODS: Fifteen weeks after surgery, rats were given control diet (0.3% calcium, 0.5% phosphate), phosphate-lowering diet (3% calcium as carbonate) or high-phosphate diet (1.5%) for 12 weeks. Sham-operated rats were on control diet. RESULTS: Blood pressure, plasma phosphate, parathyroid hormone, glomerulosclerosis, tubulointerstitial damage, and FGF-23 were increased in remnant kidney rats, whereas creatinine clearance was decreased. Phosphate, parathyroid hormone, glomerulosclerosis, tubulointerstitial damage, and FGF-23 were further elevated by the high-phosphate diet, but were reduced by the phosphate-lowering diet. Plasma calcium was increased with the phosphate-lowering diet and decreased with the high-phosphate diet. Remnant kidney rats on control diet showed upregulated kidney angiotensin-converting enzyme (ACE) and angiotensin (Ang) IV receptor (AT(4)) transcription, while ACE2, Ang II type 2 receptor and renin receptor transcription were downregulated in comparison with sham rats. Phosphate-lowering diet reduced whereas high-phosphate diet increased kidney ACE, and these effects were observed at both mRNA and protein levels. Dietary phosphate loading also resulted in lower AT(1a) gene transcription. CONCLUSION: Dietary phosphate loading was associated with elevated kidney ACE expression, increased tissue damage and lower AT(1a) transcription in 5/6 NX rats. Phosphate binding with 3% calcium carbonate had opposite effects on ACE and kidney damage.

Alterations of Cardiac Protein Kinases in Cyclic Nucleotide-Dependent Signaling Pathways in Human Ischemic Heart Failure.

Objectives: Impaired protein kinase signaling is a hallmark of ischemic heart disease (IHD). Inadequate understanding of the pathological mechanisms limits the development of therapeutic approaches. We aimed to identify the key cardiac kinases and signaling pathways in patients with IHD with an effort to discover potential therapeutic strategies. Methods: Cardiac kinase activity in IHD left ventricle (LV) and the related signaling pathways were investigated by kinomics, transcriptomics, proteomics, and integrated multi-omics approach. Results: Protein kinase A (PKA) and protein kinase G (PKG) ranked on top in the activity shift among the cardiac kinases. In the IHD LVs, PKA activity decreased markedly compared with that of controls (62% reduction, p = 0.0034), whereas PKG activity remained stable, although the amount of PKG protein increased remarkably (65%, p = 0.003). mRNA levels of adenylate cyclases (ADCY 1, 3, 5, 9) and cAMP-hydrolysing phosphodiesterases (PDE4A, PDE4D) decreased significantly, although no statistically significant alterations were observed in that of PKGs (PRKG1 and PRKG2) and guanylate cyclases (GUCYs). The gene expression of natriuretic peptide CNP decreased remarkably, whereas those of BNP, ANP, and neprilysin increased significantly in the IHD LVs. Proteomics analysis revealed a significant reduction in protein levels of "Energy metabolism" and "Muscle contraction" in the patients. Multi-omics integration highlighted intracellular signaling by second messengers as the top enriched Reactome pathway. Conclusion: The deficiency in cAMP/PKA signaling pathway is strongly implicated in the pathogenesis of IHD. Natriuretic peptide CNP could be a potential therapeutic target for the modulation of cGMP/PKG signaling.

Heat shock attenuates VEGF expression in three-dimensional myoblast sheets deteriorating therapeutic efficacy in heart failure.

BACKGROUND: Myoblast sheet transplantation is a promising novel treatment for ischemic heart failure. The aim of this study was to test the hypothesis that heat shock (HS) pre-treatment affects the angiogenic properties of myoblast sheets in vivo and in vitro. MATERIAL/METHODS: We studied HS preconditioning of L6 myoblast sheets in relation to their apoptosis, proliferation, and vascular endothelial growth factor (VEGF)-associated responses under normoxia and under hypoxia in vitro. In vivo evaluation of their therapeutic effect was performed with 60 male Wistar rats divided into 3 groups (20 each): sole left anterior descending (LAD) ligation (control); LAD ligation and non-conditioned sheet transplantation (L6 No-Shock); and LAD ligation and L6-heat shock conditioned sheet transplantation (L6 Heat-Shock). Left ventricular function was evaluated by echocardiography after 3, 10, and 28 days. RESULTS: Expression of HSP70/72 was strongly induced 24 hours after HS, and thereafter it decreased notably during 72 hours in hypoxia. Under normal growth conditions, HSP70/72 expression remained stable. HS delayed apoptosis-associated caspase-3 expression during 24-hour hypoxia compared to non-treated controls. However, VEGF expression reduced significantly in the heat shock pretreated sheets. Ejection fraction of the L6-myoblast HS pre-treatment group (L6 Heat-Shock) decreased gradually during follow-up, in the same pattern as the controls. However, these functional parameters improved in the L6-myoblast normal sheet group (L6 No-Shock) at the tenth day and remained significantly better. CONCLUSIONS: HS protects myoblast sheets from hypoxia-associated apoptosis in vitro, but reduces VEGF expression of the sheet, leading to lower therapeutic effect in heart failure.