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Cardiovascular death commonly occurs in patients with chronic kidney disease. Indoxyl sulfate (IS), a uremic toxin, has been demonstrated in vitro as a contributory factor in cardiac fibrosis, a typical pathological finding in uremic cardiomyopathy. This study aimed to determine if cardiac fibrosis is reversible by lowering serum IS levels using an oral charcoal adsorbent, AST-120. Subtotal-nephrectomized (5/6-STNx) Sprague-Dawley rats were randomized to receive either AST-120 (AST-120, n=13) or no treatment (vehicle, n=17) for 12 weeks. Sham operated rats (n=12) were used as controls. Early left ventricular (LV) diastolic dysfunction was demonstrated by an increase in peak velocity of atrial filling [A and A' waves] and a decrease of E/A and E'/A' ratios obtained by echocardiography. This was accompanied by a 4.5-fold increase in serum IS (p<0.001) as well as elevated tail-cuff blood pressure (p<0.001) and heart weight (p<0.001). Increased LV fibrosis (p<0.001), gene expression of pro-fibrotic (TGF-β, CTGF) and hypertrophic (ANP, β-MHC and α-skeletal muscle actin) markers, as well as TGF-β and phosphorylated NF-κB protein expression were observed in STNx + vehicle rats. Treatment with AST-120 reduced serum creatinine (by 54%, p<0.05) and urine total protein (by 27%, p<0.05) vs vehicle whilst having no effect on blood pressure (AST-120=227 ± 11 vs vehicle  =224 ± 8 mmHg, ns) and heart weight. The increase in serum IS was prevented with AST-120 (by 100%, p<0.001) which was accompanied by reduced LV fibrosis (68%, p<0.01) and TGF-β and phosphorylated NF-κB protein expression (back to sham levels, p<0.05) despite no significant change in LV function. In conclusion, STNx resulted in increased cardiac fibrosis and circulating IS levels. Reduction of IS with AST-120 normalizes cardiac fibrosis, in a blood pressure independent manner.

Dihydrosphingolipids refer to sphingolipids early in the biosynthetic pathway that do not contain a C4-trans-double bond in the sphingoid backbone: 3-ketosphinganine (3-ketoSph), dihydrosphingosine (dhSph), dihydrosphingosine-1-phosphate (dhS1P) and dihydroceramide (dhCer). Recent advances in research related to sphingolipid biochemistry have shed light on the importance of sphingolipids in terms of cellular signalling in health and disease. However, dihydrosphingolipids have received less attention and research is lacking especially in terms of their molecular mechanisms of action. This is despite studies implicating them in the pathophysiology of disease, for example dhCer in predicting type 2 diabetes in obese individuals, dhS1P in cardiovascular diseases and dhSph in hepato-renal toxicity. This review gives a comprehensive summary of research in the last 10–15 years on the dihydrosphingolipids, 3-ketoSph, dhSph, dhS1P and dhCer, and their relevant roles in different diseases. It also highlights gaps in research that could be of future interest.

Cardiorenal fibrosis is a common feature of chronic cardiovascular disease and recent data suggests that cytokines and chemokines may also drive fibrosis. Here we tested the hypothesis that CXCR7, a highly conserved chemokine receptor, contributes to cardiac and renal fibrosis. We generated an anti-mouse CXCR7-specific monoclonal antibody (CXCR7 mAb) and tested its anti-fibrotic actions in cardiorenal fibrosis induced using the deoxycorticosterone acetate/uni-nephrectomy (DOCA-UNX) model. CXCR7 mAb treatment (10 mg/kg, twice weekly for 6 weeks) significantly attenuated the development of cardiac and renal fibrosis, and reduced fibrotic and inflammatory gene expression levels, in the absence of an effect on blood pressure. Immunohistochemical analysis demonstrated an increase in the vascular expression of CXCR7 in DOCA-UNX-treated mice. This study demonstrated that a CXCR7 mediated pathway plays a significant role in cardiac and renal fibrosis induced by DOCA-UNX treatment. Accordingly, antagonism of CXCR7 may provide a therapeutic opportunity to mitigate against fibrosis in the setting of mineralocorticoid excess.

Pregnancy poses unique hemodynamic and metabolic demands on the heart. Recent data suggests that a history of multiple pregnancies may be associated with a late-term increased risk of heart failure with preserved ejection fraction (HFpEF), however, the mechanistic basis is unknown. We postulated that the repetitive biological and hemodynamic impact of multiple pregnancies could cause persistent myocardial remodelling providing a substrate for subsequent HFpEF. Multiparous (MP) mice (C57Bl/6J) aged 24 months were compared to age-matched non-parous (NP) mice (n = 8) in a blinded analysis. We evaluated blood pressure, body composition, gross weight and histologic cardiac structure. Cardiac function was assessed by echocardiography together with transcriptomic analysis of the left ventricular myocardium. At 15 months post oestrous cycle disruption, MP mice continued to demonstrate a constellation of myocardial alterations including higher heart to tibial length ratio ( P  < 0.05), body weight ( P  < 0.01), and fat mass ( P  < 0.01) compared to NP mice. MP mice had increased isovolumetric relaxation time ( P  < 0.01), increased end-diastolic ( P  < 0.05) and systolic volumes ( P  < 0.005), and mildly reduced left ventricular ejection fractions (LVEF) ( P  < 0.005) compared to non-parous mice. This was accompanied by marked elevations in mRNA levels of cardiac markers; Myh6 ( P  < 0.01) and Nppa ( P  < 0.01). mRNA levels of Il18 ( P  < 0.05) and the basal extracellular matrix protein–fibronectin ( P  < 0.05) were also increased, with a significant increase in interstitial fibrosis ( P  < 0.05). Bulk RNA sequencing (RNA Seq) further revealed persistent differential expression of 128 genes with over/under-represented pathways involved in extracellular matrix (ECM) regulation and organic anion/ion transport, respectively. Multiparity alters cardiac gene profile and causes myocardial remodelling that persists into later life, providing a potential foundation for the HF phenotypes such as HFpEF. Further studies are required to investigate the nature of the interaction between pregnancy-associated remodelling and other factors known to be associated with HFpEF development.

Aims Heart failure represents a substantial burden to both patients and healthcare systems worldwide. Nitric oxide (NO) dysregulation may play a key role in patients transitioning from chronic to acute heart failure with a reduced ejection fraction (HFrEF). Plasma nitrite (NO2−) is highly reflective of local nitric oxide production and has not been studied in acute HFrEF. This study aims to quantify measures of NO biology in patients with acute and chronic HFrEF. Methods and results We utilized gas‐phase chemiluminescence to determine plasma NO2− concentrations. Plasma asymmetric dimethylarginine (ADMA) and arterial stiffness were also measured. Plasma concentrations of NO2− and ADMA, in addition to arterial stiffness, were compared in participants with chronic HFrEF (n = 25) and acute HFrEF (n = 24). We observed lower concentrations of plasma NO2− in patients with acute HFrEF (P = 0.047). We also observed higher plasma concentrations of ADMA in participants with acute HFrEF (P < 0.001). Plasma NO2− and ADMA also displayed a significant negative correlation in the total cohort (Rs = −0.38, P = 0.017). There was no significant difference between groups regarding arterial stiffness measures. Conclusions We present novel data with regard to plasma NO2− in both acute and chronic HFrEF. Our results indicate that patients with acute HFrEF have a relative deficiency of plasma NO2− whilst also displaying a relative increase in ADMA, a modulator of eNOS. Reduced NO bioavailability may therefore relate to impaired NO production in patients with acute decompensation, with implications for both treatment and prevention of episodes.

Cycling is recognised as a sport in which there is a high incidence of poor bone health. Sweat calcium losses may contribute to this. To examine whether a calcium-rich pre-exercise meal attenuates exercise-induced perturbations of bone calcium homeostasis caused by maintenance of sweat calcium losses. Using a randomized, counterbalanced crossover design, 32 well-trained female cyclists completed two 90 min cycling trials separated by 1 day. Exercise trials were preceded 2 hours by either a calcium-rich (1352 ± 53 mg calcium) dairy based meal (CAL) or a control meal (CON; 46 ± 7 mg calcium). Blood was sampled pre-trial; pre-exercise; and immediately, 40 min, 100 min and 190 min post-exercise. Blood was analysed for ionized calcium and biomarkers of bone resorption (Cross Linked C-Telopeptide of Type I Collagen (CTX-I), Cross Linked C-Telopeptide of Type II Collagen (CTX-II), Parathyroid Hormone (PTH), and bone formation (Procollagen I N-Terminal Propeptide (PINP)) using the established enzyme-linked immunosorbent assay technique. PTH and CTX-I increased from pre-exercise to post-exercise in both conditions but was attenuated in CAL (p < 0.001). PTH was 1.55 [1.20, 2.01] times lower in CAL immediately post-exercise and 1.45 [1.12, 1.88] times lower at 40 min post-exercise. CTX-I was 1.40 [1.15, 1.70] times lower in CAL at immediately post-exercise, 1.30 [1.07, 1.57] times lower at 40 min post-exercise and 1.22 [1.00, 1.48] times lower at 190 min post-exercise (p < 0.05). There was no significant interaction between pre-exercise meal condition and time point for CTX-II (p = 0.732) or PINP (p = 0.819). This study showed that a calcium-rich pre-exercise breakfast meal containing ~1350 mg of calcium consumed ~90 min before a prolonged and high intensity bout of stationary cycling attenuates the exercise induced rise in markers of bone resorption--PTH and CTX-I. Australian New Zealand Clinical Trials Registry ACTRN12614000675628.

An accelerated progressive decline in renal function is a frequent accompaniment of myocardial infarction (MI). Indoxyl sulfate (IS), a uremic toxin that accumulates from the early stages of chronic kidney disease (CKD), is contributory to both renal and cardiac fibrosis. IS levels can be reduced by administration of the oral adsorbent AST-120, which has been shown to ameliorate pathological renal and cardiac fibrosis in moderate to severe CKD. However, the cardiorenal effect of AST-120 on less severe renal dysfunction in the post-MI setting has not previously been well studied. MI-induced Sprague-Dawley rats were randomized to receive either AST-120 (MI+AST-120) or were untreated (MI+Vehicle) for 16 weeks. Serum IS levels were measured at baseline, 8 and 16 weeks. Echocardiography and glomerular filtration rate (GFR) were assessed prior to sacrifice. Renal and cardiac tissues were assessed for pathological changes using histological and immunohistochemical methods, Western blot analysis and real-time PCR. Compared with sham, MI+Vehicle animals had a significant reduction in left ventricular ejection fraction (by 42%, p<0.001) and fractional shortening (by 52%, p<0.001) as well as lower GFR (p<0.05) and increased serum IS levels (p<0.05). A significant increase in interstitial fibrosis in the renal cortex was demonstrated in MI+Vehicle animals (p<0.001). Compared with MI+Vehicle, MI+AST-120 animals had increased GFR (by 13.35%, p<0.05) and reduced serum IS (p<0.001), renal interstitial fibrosis (p<0.05), and renal KIM-1, collagen-IV and TIMP-1 expression (p<0.05). Cardiac function did not change with AST-120 treatment, however gene expression of TGF-β1 and TNF-α as well as collagen-I and TIMP-1 protein expression was decreased in the non-infarcted myocardium (p<0.05). In conclusion, reduction of IS attenuates cardio-renal fibrotic processes in the post-MI kidney. KIM-1 appears to be a sensitive renal injury biomarker in this setting and is correlated with serum IS levels.

Heart failure with preserved ejection fraction (HFpEF) currently accounts for half of the heart failure (HF) cases world-wide, affecting nearly 32 million people. HFpEF has a skewed prevalence toward females and those older than 65 years old. The pathophysiology of HFpEF is suggestive of a conglomerate of inflammatory, hypertensive, as well as metabolic dysfunction, giving rise to the syndrome. Disruptions in ceramide metabolism do occur in heart failure as well as within the HFpEF-associated risk factors, both modifiable inflammation, obesity, hypertension, diabetes, and non-modifiable-aging, and female sex. The focus of this review is to draw attention to the links between changes in female biophysiology, such as pregnancy, menopause and aging, in which ceramide is dysregulated and consequently gives rise to the same pathologies that are labeled as risk factors for HFpEF. Our objective is to highlight ceramides as potential biomarkers for prevention and initial diagnostic tools for HFpEF, especially for women later in life.

Human cytomegalovirus (HCMV) infections are common following renal transplantation and may have long-lasting effects. HCMV can be measured directly by viral DNA or indirectly via host immune responses. HCMV-encoded microRNA (miRNA) may alter the pathobiology of HCMV infections and contribute to the progression of HCMV disease. HCMV-encoded miRNAs can be detected in blood but have not been sought in saliva. We investigated saliva samples from 32 renal transplant recipients (RTR) and 12 seropositive healthy controls for whom immunological data was available. Five HCMV-encoded miRNAs (miR-UL112-5p, miR-US5-2-3p, miR-UL36, miR-US25-2-3p and miR-UL22A) were sought using primer probe assays. HCMV miRNA species were detected in saliva from 15 RTR and 3 healthy controls, with miR-US5-2-3p most commonly detected. The presence of HCMV miRNAs associated with increased T-cell responses to HCMV IE-1 in RTR, suggesting a link with frequent reactivations of HCMV.

•Cardiovascular aging is associated with myocardial dysfunction, with consequent atrial fibrillation and heart failure.•STAREE-HEART is a clinical trial assessing the effect of atorvastatin compared with placebo on markers of cardiovascular aging in a healthy older population.•A total of 369 participants underwent a comprehensive cardiac evaluation before randomization, which will be repeated at 3 years.•Atorvastatin may provide a population-wide prevention strategy for cardiovascular aging. Statins may prevent myocardial dysfunction associated with aging, and consequent atrial fibrillation (AF) and heart failure (HF). STAREE-HEART is a randomized, double-blind, placebo-controlled clinical trial assessing atorvastatin on markers of cardiovascular aging in a healthy older population. This ancillary study is nested in the STAtins in Reducing Events in the Elderly (STAREE) primary prevention trial. Participants ≥ 70 years (n = 369) have been randomized to atorvastatin or placebo. Assessment at baseline and 3-years includes echocardiogram, electrocardiography and blood collection for biomarker assessment. The primary endpoint is change in global longitudinal strain (GLS), a measure of left ventricular systolic function. An estimated 184 participants per group enables detection of mean GLS at 3 years in the placebo group being 2.0 percentage points lower than mean GLS in the statin group at 3 years, assuming SD = 5 percentage points and a 15% attrition rate, with power >90%. We present summary statistics describing participants at baseline. The mean age of the 369 STAREE-HEART participants was 73.0 years (SD 3.4). Mean left ventricular (LV) ejection fraction was 64.0% (SD 6.1), and mean GLS was 19.2% (SD 2.2). Mean GLS was similar between females and males (19.4% vs 19.0%) and slightly higher in those aged 70 to 74 compared to ≥75 years (19.4% vs 18.6%). AF was detected on screening in 4.5% of participants. The STAREE-HEART ancillary study will provide mechanistic detail concerning myocardial dysfunction and its consequences, to determine if atorvastatin affects left ventricular systolic function associated with aging. clinicaltrials.gov. Unique identifier: NCT04536870.