Vulnerability to environmental and climatic health provocations among women and men hospitalized with chronic heart disease: insights from the RESILIENCE TRIAL cohort

AIMS

We aimed to recruit a representative cohort of women and men with multi-morbid chronic heart disease as part of a trial testing an innovative, nurse-co-ordinated, multi-faceted intervention to lower rehospitalization and death by addressing areas of vulnerability to external challenges to their health.

METHODS AND RESULTS

The prospective, randomized open, blinded end-point RESILIENCE Trial recruited 203 hospital inpatients (mean age 75.7 ± 10.2 years) of whom 51% were women and 94% had combined coronary artery disease, heart failure, and/or atrial fibrillation. Levels of concurrent multi-morbidity were high (mean Charlson Index of Comorbidity Score 6.5 ± 2.7), and 8.9% had at least mild frailty according to the Rockwood Clinical Frailty Scale. Including the index admission, 19-20% of women and men had a pre-existing pattern of seasonally linked hospitalization (seasonality). Detailed phenotyping revealed that 48% of women and 40% of men had ≥3 physiological factors, and 15% of women and 16% of men had ≥3 behavioural factors likely to increase their vulnerability to external provocations to their health. Overall, 61-62% of women and men had ≥4 combined factors indicative of such vulnerability. Additional factors such as reliance on the public health system (63 vs. 49%), lower education (30 vs. 14%), and living alone (48 vs. 29%) were more prevalent in women.

CONCLUSION

We successfully recruited women and men with multi-morbid chronic heart disease and bio-behavioural indicators of vulnerability to external provocations to their health. Once completed, the RESILIENCE TRIAL will provide important insights on the impact of addressing such vulnerability (promoting resilience) on subsequent health outcomes.

REGISTRATION

ClinicalTrials.org: NCT04614428.

Renin-angiotensin-aldosterone system dynamics after targeted blood pressure control using angiotensin II or norepinephrine in cardiac surgery: mechanistic randomised controlled trial

BACKGROUND

The role of the renin-angiotensin-aldosterone axis in vasoplegia after cardiac surgery remains unclear. We tested the hypothesis that, compared with norepinephrine, infusion of angiotensin II titrated to achieve similar mean arterial pressure (MAP) would suppress plasma renin concentration (PRC) while maintaining aldosterone levels.

METHODS

In a double-blind, randomised controlled trial, subjects received either an infusion of angiotensin II or norepinephrine to maintain MAP 70-80 mm Hg from induction of anaesthesia. We compared PRC, aldosterone, dipeptidyl peptidase-3, and angiotensin-converting enzyme 2 activity between treatment groups, before surgery, on ICU admission, and 24 h after surgery.

RESULTS

In 60 patients (11.7% female; mean age 68 yr [11 yr]), norepinephrine increased median PRC at ICU admission (median difference [MD] 46 [inter-quartile range, IQR, 3-88] μU ml-1; P<0.001) but angiotensin II did not (MD -3 [IQR -62 to 35] μU ml-1; P=0.36). Aldosterone levels increased with both. The aldosterone:PRC ratio did not change with norepinephrine (MD -0.01 [IQR -0.14 to 0.03] μU ml-1 per ng dl-1, P=0.76) but increased with angiotensin II (MD 0.05 [IQR 0.004-0.26] μU ml-1 per ng dl-1, P<0.001). The upper quartile of PRC before surgery was associated with higher vasopressor requirements when norepinephrine was used to maintain MAP, but not angiotensin II. Dipeptidyl peptidase-3 levels and angiotensin-converting enzyme 2 activities were similar at all time points.

CONCLUSIONS

Angiotensin II suppressed renin release while maintaining aldosterone levels compared with norepinephrine. Higher plasma renin concentration before surgery was associated with greater vasopressor requirement for norepinephrine, but not angiotensin II.

CLINICAL TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry-ACTRN12621000195853 23/02/2021.

Global coagulation assays in patients with chronic kidney disease and their role in predicting thrombotic risk

BACKGROUND

Despite cardiovascular diseases and thrombosis being major causes of death in patients with chronic kidney disease (CKD), there remains no effective biomarker to predict thrombotic risk in this population.

OBJECTIVE

To evaluate global coagulation assays in patients with CKD and correlate the biomarkers to clinical outcomes.

MATERIAL AND METHODS

Patients with eGFR<30 mL/min/1.73m² were recruited (n = 90) in this prospective observational study. Blood samples were collected for global coagulation assays, including thromboelastography, calibrated automated thrombogram (CAT), overall hemostatic potential (OHP) and tissue factor pathway inhibitor (TFPI).

RESULTS

Following adjustment for age and gender, CKD subjects (mean age 66 years, 36 % female) had increased maximum amplitude on thromboelastography (70.1 vs 60.2 mm, p < 0.001), higher peak thrombin (233.2 vs 219.7 mm, p = 0.030) and increased OHP (16.1 vs 6.4 units, p < 0.001) compared to healthy controls (n = 153). TFPI was also increased in CKD patients (36.4 vs 14.5 ng/mL, p < 0.001). Compared to hemodialysis patients (n = 43), peritoneal-dialysis patients (n = 25) had more hypercoagulable parameters. Thirty-five CKD patients reported thrombotic complications - key predictors included dialysis, higher fibrinogen, reduced endogenous thrombin potential, elevated D-dimer and increased TFPI. Using the dialysis cohort, the predictive risk model based on the key predictors performed better than Framingham heart score and number of cardiovascular risk factors (Harrell's C-stat 0.862 vs 0.585 vs 0.565).

CONCLUSION

CKD appears to confer a hypercoagulable state compared to healthy controls. Interestingly, reduced thrombin generation and raised TFPI was paradoxically associated with increased thrombotic risks, highlighting possible complex compensatory mechanisms within the coagulation system, which may be important in predicting clinical outcomes.

Corrigendum: Fc engineered ACE2-Fc is a potent multifunctional agent targeting SARS-CoV2

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Somatic Mosaic Pathogenic Variant Gradient Detected in Trace Brain Tissue From Stereo-EEG Depth Electrodes

BACKGROUND AND OBJECTIVES

Mosaic pathogenic variants restricted to the brain are increasingly recognized as a cause of focal epilepsies. We aimed to identify a mosaic pathogenic variant and its anatomical gradient in brain DNA derived from trace tissue on explanted stereoelectroencephalography (SEEG) electrodes.

METHODS

We studied a patient with nonlesional multifocal epilepsy undergoing presurgical evaluation with SEEG. After explantation, the electrodes were divided into 3 pools based on their brain location (right posterior quadrant, left posterior quadrant, hippocampus/temporal neocortex). Tissue from each pool was processed for trace DNA that was whole genome amplified prior to high-depth exome sequencing. Droplet digital PCR was performed to quantify mosaicism. A brain-specific glial fibrillary acidic protein (GFAP) assay enabled cell-of-origin analysis.

RESULTS

We demonstrated a mosaic gradient for a novel pathogenic KCNT1 loss-of-function variant (c.530G>A, p.W177X) predicted to lead to nonsense-mediated decay. Strikingly, the mosaic gradient correlated strongly with the SEEG findings because the highest variant allele frequency was in the right posterior quadrant, reflecting the most epileptogenic region on EEG studies. An elevated GFAP level indicated enrichment of brain-derived cells in SEEG cell suspension.

DISCUSSION

This study demonstrates a proof of concept that mosaic gradients of pathogenic variants can be established using trace tissue from explanted SEEG electrodes.

Plasma Neurofilament Light Chain and Clinical Diagnosis in Frontotemporal Dementia Syndromes

Background: Frontotemporal dementia (FTD) syndromes, mimics, phenocopy (phFTD), and slowly progressive behavioral variant FTD (bvFTD) can be difficult to distinguish clinically. Biomarkers such as neurofilament light chain (NfL) may be helpful. Objective: To study plasma NfL levels in people with FTD syndromes and determine if plasma NfL can distinguish between FTD syndromes and phFTD. Methods: Plasma NfL levels were estimated using both Simoa ® Quanterix HD-X™ and SR-X™ machines grouped via final diagnosis after investigation and review. Results: Fifty participants were studied: bvFTD = 20, semantic variant FTD (svFTD) = 11, non-fluent variant FTD (nfvFTD) = 9, FTD with motor neuron disease (MND) = 4, phFTD = 2, slow progressors = 3, FTD mimic = 1, mean age 67.2 (SD 8.4) years. NfL levels were significantly higher in the FTD group compared to phenocopy group (p = 0.003). Median NfL (IQR) pg/mL was comparable in the FTD syndromes: bvFTD 41.10 (50.72), svFTD 44.38 (16.61), and nfvFTD 42.61 (22.93), highest in FTD with MND 79.67 (45.32) and lowest in both phFTD 13.99 (0.79) and slow progressors 17.97 (3.62). Conclusion: Plasma NfL appears to differentiate FTD syndromes and mimics. However, a lower NfL may predict a slower, but not necessarily lack of, neurodegeneration and therefore appears limited distinguishing slow progressors from FTD phenocopies. Larger numbers of patients from all clinical groups are required to strengthen diagnostic utility.

Fc engineered ACE2-Fc is a potent multifunctional agent targeting SARS-CoV2

Joining a function-enhanced Fc-portion of human IgG to the SARS-CoV-2 entry receptor ACE2 produces an antiviral decoy with strain transcending virus neutralizing activity. SARS-CoV-2 neutralization and Fc-effector functions of ACE2-Fc decoy proteins, formatted with or without the ACE2 collectrin domain, were optimized by Fc-modification. The different Fc-modifications resulted in distinct effects on neutralization and effector functions. H429Y, a point mutation outside the binding sites for FcγRs or complement caused non-covalent oligomerization of the ACE2-Fc decoy proteins, abrogated FcγR interaction and enhanced SARS-CoV-2 neutralization. Another Fc mutation, H429F did not improve virus neutralization but resulted in increased C5b-C9 fixation and transformed ACE2-Fc to a potent mediator of complement-dependent cytotoxicity (CDC) against SARS-CoV-2 spike (S) expressing cells. Furthermore, modification of the Fc-glycan enhanced cell activation via FcγRIIIa. These different immune profiles demonstrate the capacity of Fc-based agents to be engineered to optimize different mechanisms of protection for SARS-CoV-2 and potentially other viral pathogens.

Immunological dysfunction persists for 8 months following initial mild-to-moderate SARS-CoV-2 infection

A proportion of patients surviving acute coronavirus disease 2019 (COVID-19) infection develop post-acute COVID syndrome (long COVID (LC)) lasting longer than 12 weeks. Here, we studied individuals with LC compared to age- and gender-matched recovered individuals without LC, unexposed donors and individuals infected with other coronaviruses. Patients with LC had highly activated innate immune cells, lacked naive T and B cells and showed elevated expression of type I IFN (IFN-β) and type III IFN (IFN-λ1) that remained persistently high at 8 months after infection. Using a log-linear classification model, we defined an optimal set of analytes that had the strongest association with LC among the 28 analytes measured. Combinations of the inflammatory mediators IFN-β, PTX3, IFN-γ, IFN-λ2/3 and IL-6 associated with LC with 78.5-81.6% accuracy. This work defines immunological parameters associated with LC and suggests future opportunities for prevention and treatment.

Retinal microvascular function predicts chronic kidney disease in patients with cardiovascular risk factors

BACKGROUND AND AIMS

Endothelial dysfunction is a precursor to atherosclerosis and is implicated in the coexistence between cardiovascular disease (CVD) and chronic kidney disease (CKD). We examined whether retinal microvascular dysfunction is present in subjects with renal impairment and predictive of long-term CKD progression in patients with CVD.

METHODS

In a single centre prospective observational study, 253 subjects with coronary artery disease and CVD risk factors underwent dynamic retinal vessel analysis. Retinal microvascular dysfunction was quantified by measuring retinal arteriolar and venular dilatation in response to flicker light stimulation. Serial renal function assessment was performed over a median period of 9.3 years using estimated GFR (eGFR).

RESULTS

Flicker light-induced retinal arteriolar dilatation (FI-RAD) was attenuated in patients with baseline eGFR <90 mL/min/1.73 m², compared to those with normal renal function (eGFR ≥90 mL/min/1.73 m²) (1.0 [0.4-2.1]% vs. 2.0 [0.8-3.6]%; p < 0.01). In patients with normal renal function, subjects with the lowest FI-RAD responses exhibited the greatest annual decline in eGFR. In uni- and multivariable analysis, among subjects with normal renal function, a 1% decrease in FI-RAD was associated with an accelerated decline in eGFR of 0.10 (0.01, 0.15; p = 0.03) and 0.07 mL/min/1.73 m² per year (0.00, 0.14; p = 0.06), respectively. FI-RAD was not predictive of CKD progression in subjects with baseline eGFR <90 mL/min/1.73 m².

CONCLUSIONS

Retinal arteriolar endothelial dysfunction is present in patients with CVD who have early-stage CKD, and serves as an indicator of long-term CKD progression in those with normal renal function.

No dynamic changes in plasma ACE2 activity in patients with acute coronary syndrome

Background

Angiotensin converting enzyme 2 (ACE2) is expressed in the human myocardium and blood vessels and degrades the vasoconstrictor peptide angiotensin (Ang) II. Plasma ACE2 activity is elevated in patients with cardiovascular disease (CVD) and is a predictor of major adverse cardiovascular events (MACE) in obstructive coronary artery disease. However, it is unknown whether acute coronary syndrome (ACS) causes dynamic changes in plasma ACE2 activity.

Purpose

We investigated dynamic changes in serial troponin-T and plasma ACE2 activity in patients presenting with ACS who underwent invasive coronary angiography (ICA).

Methods

Consecutive patients admitted with ACS from October-November 2019 were screened. Those meeting the Fourth Universal Definition of Myocardial Infarction who had both ICA and serial troponin-T testing were included. The study was approved by the hospitals Human Research Ethics Committee. All patients had routine plasma samples taken over 3 time-points for measurement of troponin-T; the same sample was used to measure plasma ACE2 activity. Catalytic ACE2 activity was measured using a validated, sensitive quenched fluorescent substrate-based assay. Serial median troponin and ACE2 activity levels were analysed using the Friedman test for repeated measures.

Results

Forty-nine patients were included. The mean age of participants was 63.9±11.0 years, and 36 (74%) patients were male. Overall, 16 (36%) patients presented with ST-elevation myocardial infarction (STEMI) and 29 (74%) with non-ST-elevation myocardial infarction (NSTEMI). Twenty-nine (59%) patients had a history of hypertension and 14 (29%) a history of ischaemic heart disease; 13 (27%) with priorMI, 11 (22%) had previous PCI and 2 (4%) had prior coronary artery bypass grafting. Over the 3 time points, there was a clear rise in median troponin-T levels representing myocardial injury (p&lt;0.001), with no change in median plasma ACE2 activity (p=0.23, table 1). There was no difference in median ACE2 activity in those presenting with STEMI vs. NSTEMI (6.9 [2.1–9.5] vs. 6.0 [1.8–12.1], p=0.87), nor in those who underwent PCI to a culprit lesion compared to those who did not have a culprit lesion stented (5.8 [0.9–10.5] vs. 7.3 [2.8–14.9], p=0.37).

Conclusions

Patients with ACS had higher plasma ACE2 levels compared to levels previously reported in healthy controls. There were no dynamic changes in ACE2 activity in the setting of ACS, despite a significant rise in troponin-T. These results suggest that plasma ACE2 levels reflect underlying endothelial dysfunction rather than acute myocardial injury or infarction. Studies are now underway to assess if plasma ACE2 activity in ACS predicts MACE.

Funding Acknowledgement

Type of funding sources: None. Table 1

Angiotensin-Converting Enzyme 2 Activity Is Associated With Embolic Stroke of Undetermined Source

[Figure: see text].

Plasma ACE2 activity is persistently elevated following SARS-CoV-2 infection: implications for COVID-19 pathogenesis and consequences

Coronavirus disease 2019 (COVID-19) causes persistent endothelial inflammation, lung, cardiovascular, kidney and neurological complications, and thromboembolic phenomena of unclear pathogenesis [1]. Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) utilises the catalytic site of full-length membrane-bound angiotensin converting enzyme 2 (ACE2) for host cell entry [2], which is thought to downregulate membrane-bound ACE2, and thus contribute to ongoing inflammation due to loss of a degradative pathway for angiotensin II. In healthy individuals, ACE2 exists primarily in its membrane-bound form with very low levels of the catalytically active ectodomain of ACE2 present in the circulation [3]. However, in patients with cardiovascular disease, there is increased “shedding” of ACE2, and higher circulating levels are associated with downregulation of membrane-bound ACE2 [4].

Plasma ACE2 activity is persistently elevated in patients after COVID-19 infection. Larger studies are needed to determine if this identifies people at risk of prolonged illness following COVID-19.https://bit.ly/2XQlrYF

Medical Care Disruptions During the First Six-Months of the COVID19 Pandemic: The Experience of Older Breast Cancer Survivors

Purpose.

Older cancer survivors required medical care during the COVID-19 pandemic despite infection risks, but there are limited data on medical care in this age group.

Methods.

We evaluated care disruptions in a longitudinal cohort of non-metastatic breast cancer survivors ages 60–98 from five US regions (n=321). Survivors completed a web-based or telephone survey from May 27, 2020 to September 11, 2020. Care disruptions included self-reported interruptions in ability to see doctors, receive treatment or supportive therapies, or fill prescriptions. Logistic regression models evaluated bivariate and multivariate associations between care disruptions and education, medical, psychosocial and COVID-19-related factors. Multivariate models included age, county COVID-19 rates, comorbidity and post-diagnosis time.

Results.

There was a high response rate (n=262, 81.6%). Survivors were 32.2 months post-diagnosis (SD 17.5, range 4–73). Nearly half (48%) reported a medical disruption. The unadjusted odds of care disruptions were significantly higher with more education (OR 1.23 per one-year increase, 95% CI 1.09–1.39, p =0.001) and greater depression (OR 1.04 per one-point increase in CES-D score, CI 1.003–1.08, p=0.033); tangible support decreased the odds of disruptions (OR 0.99, 95% CI 0.97–0.99 per one-point increase, p=0.012). There was a trend for associations between disruptions and comorbidity (unadjusted OR 1.13 per 1 added comorbidity, 95% CI 0.99–1.29, p=0.07). Adjusting for covariates, only higher education (p=0.001) and tangible social support (p=0.006) remained significantly associated with having care disruptions.

Conclusions.

Older breast cancer survivors reported high rates of medical care disruptions during the COVID-19 pandemic and psychosocial factors were associated with care disruptions.

Reduced urinary levels of angiotensin-converting enzyme 2 activity predict acute kidney injury in critically ill patients

Objective: Angiotensin-converting enzyme 2 activity reflects non-classical renin-angiotensin system upregulation. We assessed the association of urinary angiotensin-converting enzyme 2 (uACE2) activity with acute kidney injury (AKI). Design, setting and participants: A prospective observational study in which we measured uACE2 activity in 105 critically ill patients at risk of AKI. We report AKI stage 2 or 3 at 12 hours of urine collection (AKI12h) and AKI stage 2 or 3 at any time during intensive care unit stay in patients free from any stage of AKI at inclusion (AKIICU). AKI prediction was assessed using area under the receiver-operating characteristics curve (AUROC) and net reclassification indices (NRIs). Main outcome measure: AKI stage 2 or 3 at 12 hours of urine collection. Results: Within 12 hours of inclusion, 32 of 105 patients (30%) had developed AKI12h. Corrected uACE2 activity was significantly higher in patients without AKI12h compared with those with AKI12h (median [interquartile range], 13 [6-24] v 7 [4-10] pmol/min/mL per mmol/L of urine creatinine; P < 0.01). A 10-unit increase in uACE2 was associated with a 28% decrease in AKI12h risk (odds ratio [95% CI], 0.72 [0.46-0.97]). During intensive care unit admission, 39 of 76 patients (51%) developed AKIICU. uACE2 had an AUROC for the prediction of AKI12h of 0.68 (95% CI, 0.57-0.79), and correctly reclassified 28% of patients (positive NRI) to AKI12h. Patients with uACE2 > 8.7 pmol/min/mL per mmol/L of urine creatinine had a significantly lower risk of AKIICU on log-rank analysis (52% v 84%; P < 0.01). Conclusions: Higher uACE2 activity was associated with a decreased risk of AKI stage 2 or 3. Our findings support future evaluations of the role of the non-classical renin-angiotensin system during AKI.

APOE ɛ4 Carriers Show Delayed Recovery of Verbal Memory and Smaller Entorhinal Volume in the First Year After Ischemic Stroke

BACKGROUND

The apolipoprotein E (APOE) gene ɛ4 allele is a risk factor for Alzheimer's disease and cardiovascular disease. However, its relationship with cognition and brain volume after stroke is not clear.

OBJECTIVE

We compared cognition and medial temporal lobe volumes in APOEɛ4 carriers and non-carriers in the first year after ischemic stroke.

METHODS

We sampled 20 APOEɛ4 carriers and 20 non-carriers from a larger cohort of 135 ischemic stroke participants in the longitudinal CANVAS study. Participants were matched on a range of demographic and stroke characteristics. We used linear mixed-effect models to compare cognitive domain z-scores (attention, processing speed, executive function, verbal and visual memory, language, visuospatial function) and regional medial temporal lobe volumes (hippocampal, entorhinal cortex) between groups at each time-point (3, 12-months post-stroke), and within groups across time-points. APOE gene single nucleotide polymorphisms (SNPs; rs7412, rs429358) were genotyped on venous blood.

RESULTS

APOEɛ4 carriers and non-carriers did not differ on any demographic, clinical, or stroke variable. Carriers performed worse than non-carriers in verbal memory at 3 months post-stroke (p = 0.046), but were better in executive function at 12 months (p = 0.035). Carriers demonstrated a significant improvement in verbal memory (p = 0.012) and executive function (p = 0.015) between time-points. Non-carriers demonstrated a significant improvement in visual memory (p = 0.0005). Carriers had smaller bilateral entorhinal cortex volumes (p < 0.05), and larger right sided and contralesional hippocampal volumes, at both time-points (p < 0.05).

CONCLUSION

APOE ɛ4 is associated with delayed recovery of verbal memory function and reduced entorhinal cortex volumes in the first year after ischemic stroke.

Impaired retinal microvascular function predicts long-term adverse events in patients with cardiovascular disease

AIMS

Endothelial dysfunction is a precursor to the development of symptomatic atherosclerosis. Retinal microvascular reactivity to flicker light stimulation is a marker of endothelial function and can be quantified in vivo. We sought to determine whether retinal microvascular endothelial dysfunction predicts long-term major adverse cardiovascular events (MACE).

METHODS AND RESULTS

In a single-centre prospective observational study, patients with coronary artery disease (CAD) or cardiovascular risk factors underwent dynamic retinal vessel assessment in response to flicker light stimulation and were followed up for MACE. Retinal microvascular endothelial dysfunction was quantified by measuring maximum flicker light-induced retinal arteriolar dilatation (FI-RAD) and flicker light-induced retinal venular dilatation (FI-RVD). In total, 252 patients underwent dynamic retinal vessel assessment and 242 (96%) had long-term follow-up. Of the 242 patients, 88 (36%) developed MACE over a median period of 8.6 years (interquartile range 6.0-9.1). After adjustment for traditional risk factors, patients within the lowest quintile of FI-RAD had the highest risk of MACE [odds ratio (OR) 5.21; 95% confidence interval (CI) 1.78-15.28]. Patients with lower FI-RAD were also more likely to die (OR 2.09; 95% CI 1.00-4.40, per standard deviation decrease in FI-RAD). In Kaplan-Meier analysis, patients with FI-RAD responses below the cohort median of 1.4% exhibited reduced MACE-free survival (55.5 vs. 71.5%; log-rank P = 0.004). FI-RVD was not predictive of MACE.

CONCLUSION

Retinal arteriolar endothelial dysfunction is an independent predictor of MACE in patients with CAD or cardiovascular risk factors. Dynamic retinal vessel analysis may provide added benefit to traditional risk factors in stratifying patients at risk for cardiovascular events.

Imbalance of the renin-angiotensin system may contribute to inflammation and fibrosis in IBD: a novel therapeutic target?

OBJECTIVE

We evaluated the influence of the renin-angiotensin system (RAS) on intestinal inflammation and fibrosis.

DESIGN

Cultured human colonic myofibroblast proliferation and collagen secretion were assessed following treatment with angiotensin (Ang) II and Ang (1-7), their receptor antagonists candesartan and A779, and the ACE inhibitor captopril. Circulating and intestinal RAS components were evaluated in patients with and without IBD. Disease outcomes in patients with IBD treated with ACE inhibitors and angiotensin receptor blockers (ARBs) were assessed in retrospective studies.

RESULTS

Human colonic myofibroblast proliferation was reduced by Ang (1-7) in a dose-dependent manner (p<0.05). Ang II marginally but not significantly increased proliferation, an effect reversed by candesartan (p<0.001). Colonic myofibroblast collagen secretion was reduced by Ang (1-7) (p<0.05) and captopril (p<0.001), and was increased by Ang II (p<0.001). Patients with IBD had higher circulating renin (mean 25.4 vs 18.6 mIU/L, p=0.026) and ACE2:ACE ratio (mean 0.92 vs 0.69, p=0.015) than controls without IBD. RAS gene transcripts and peptides were identified in healthy and diseased bowels. Colonic mucosal Masson's trichrome staining correlated with Ang II (r=0.346, p=0.010) and inversely with ACE2 activity (r=-0.373, p=0.006). Patients with IBD who required surgery (1/37 vs 12/75, p=0.034) and hospitalisation (0/34 vs 8/68, p=0.049) over 2 years were less often treated with ACE inhibitors and ARBs than patients not requiring surgery or hospitalisation.

CONCLUSIONS

The RAS mediates fibrosis in human cell cultures, is expressed in the intestine and perturbed in intestinal inflammation, and agents targeting this system are associated with improved disease outcomes.

P5740ACE2 activity level is associated with embolic stroke of undetermined source

Background

ACE2 activity levels correlate with adverse left atrial remodelling in patients with atrial fibrillation (AF). Several biochemical and structural markers have been associated with embolic stroke of undetermined source (ESUS). The relationship between ACE2 activity and ESUS is unknown.

Purpose

Randomised controlled trials failed to demonstrate a clear benefit of oral anticoagulation in an unselected ESUS population. As selective use of oral anticoagulation guided by biomarker risk-profiling may benefit these patients, we evaluated the association between ACE2 activity and ESUS.

Methods

This prospective case control study compared patients with ESUS against a control group matched for vascular risk factors. ESUS was diagnosed following cerebral vascular imaging and 24 hours of cardiac monitoring to exclude AF. Blood samples were collected for measurement of ACE2 activity, D-Dimer and high sensitivity troponin T (hsTnT).

Results

A total of 51 patients in the ESUS group were compared with 47 patients in the Control group. ACE2 activity and D-Dimer levels were significantly higher in the ESUS group. There was a significant but weak positive correlation between ACE2 activity and hsTnT (r=0.20, p<0.05). Left atrial volume index (LAVI) on echocardiography was significantly higher in the ESUS group. On regression modelling adjusting for LAVI, only ACE2 activity remained significant for ESUS, with a 20% rise in odds for every 4 unit increase in ACE2 activity (OR 1.20; 95% CI: 1.01 - 1.36, p=0.04).

Participant characteristics Control (n=47) ESUS (n=51) P value Age (years) 65.65±6.78 67.20±6.89 0.26 Female gender 22 (45.8) 19 (38.0) 0.43 Hypertension 22 (45.8) 24 (48.0) 0.83 Diabetes mellitus 9 (18.8) 12 (24.0) 0.53 CHA2DS2VASc score 2 (1–3) 2 (1–3) 0.50 LA size & Biomarkers   LA volume index (ml/m2) 36.5 (32.6–42.5) 39.1 (36.2–46.0) 0.04   ACE2 (pmol/ml/min) 7.24 (2.66–14.64) 10.16 (4.54–18.80) 0.04   D-Dimer (mg/L) 0.35 (0.3–0.5) 0.40 (0.30–0.60) 0.02   hsTroponin T (ng/L) 7.0 (5–10) 9.00 (6.0–13.5) 0.05 Values are expressed as mean ± standard deviation, median (IQR), or n (%).

Median ACE2 activity

Conclusion(s)

ACE2 activity is associated with ESUS independent of left atrial volume and correlate with elevated Troponin. Further studies are warranted to investigate the utility of ACE2 activity in identifying ESUS patients that may benefit from oral anticoagulation.

Acknowledgement/Funding

This study received project funding from the Eastern Health Foundation

Plasma ACE2 Activity Predicts Mortality in Aortic Stenosis and Is Associated With Severe Myocardial Fibrosis

OBJECTIVES

This study investigated the relationship between plasma angiotensin-converting enzyme 2 (ACE2) activity levels and the severity of stenosis and myocardial remodeling in patients with aortic stenosis (AS) and determined if plasma ACE2 levels offered incremental prognostic usefulness to predict all-cause mortality.

BACKGROUND

ACE2 is an integral membrane protein that degrades angiotensin II and has an emerging role as a circulating biomarker of cardiovascular disease.

METHODS

Plasma ACE2 activity was measured in 127 patients with AS; a subgroup had myocardial tissue collected at the time of aortic valve replacement.

RESULTS

The median plasma ACE2 activity was 34.0 pmol/ml/min, and levels correlated with increased valvular calcification (p = 0.023) and the left ventricular (LV) mass index (r = 0.34; p < 0.001). Patients with above-median plasma ACE2 had higher LV end-diastolic volume (57 ml/m² vs. 48 ml/m²; p = 0.021). Over a median follow-up of 5 years, elevated plasma ACE2 activity was an independent predictor of all-cause mortality after adjustment for relevant clinical, imaging, and biochemical parameters (HR: 2.28; 95% CI: 1.03 to 5.06; p = 0.042), including brain natriuretic peptide activation (integrated discrimination improvement: 0.08; p < 0.001). In 22 patients with plasma and tissue, increased circulating ACE2 was associated with reduced myocardial ACE2 gene expression (0.7-fold; p = 0.033) and severe myocardial fibrosis (p = 0.027).

CONCLUSIONS

In patients with AS, elevated plasma ACE2 was a marker of myocardial structural abnormalities and an independent predictor of mortality with incremental value over traditional prognostic markers. Loss of ACE2 from the myocardium was associated with increased fibrosis and higher circulating ACE2 levels.

Plasma endothelin-1 and adrenomedullin are associated with coronary artery function and cardiovascular outcomes in humans

BACKGROUND

Endothelin-1 (ET-1) is a vasoconstrictor associated with cardiovascular disease, whereas adrenomedullin (ADM) is a vasorelaxant with cardioprotective properties. We sought to determine the relationship between plasma ET-1 and ADM with coronary circulatory function and long-term major adverse cardiovascular events (MACE).

METHODS

Thirty-two patients undergoing coronary angiography for chest pain were recruited. Baseline plasma ET-1 and ADM levels were measured. The index of microcirculatory resistance (IMR), coronary flow mediated dilatation (cFMD) and coronary flow reserve (CFR) were measured in a non-obstructed coronary artery. Patients were assessed for MACE over a median period of 8.8 years.

RESULTS

Plasma ET-1 levels correlated with IMR (r = 0.57; p < 0.01) and ADM levels correlated with CFR (r = 0.50; p = 0.04) and cFMD (r = 0.62; p = 0.01). After adjustment for age, gender and cardiovascular risk factors, the association between ADM and cFMD (β = 0.79; p < 0.01) and between ET-1 and IMR (β = 5.7; p = 0.01) remained significant. IMR was higher, although not statistically significant, in patients with long-term MACE (17.9 ± 5.3 vs. 13.1 ± 6.0 units; p = 0.14). In patients free of MACE, cFMD (9.3 ± 7.6 vs. 2.8 ± 5.0%; p = 0.01) and plasma ADM levels (7.6 ± 5.3 vs. 4.0 ± 1.9 pmol/L; p = 0.07) were higher.

CONCLUSIONS

Plasma ET-1 and ADM were associated with measures of coronary microvascular and coronary conduit vessel function, respectively. Increased cFMD and elevated plasma ADM were associated with a cardioprotective effect.

Left ventricular hypertrophy in experimental chronic kidney disease is associated with reduced expression of cardiac Kruppel-like factor 15

Background

Left ventricular hypertrophy (LVH) increases the risk of death in chronic kidney disease (CKD). The transcription factor Kruppel-like factor 15 (KLF15) is expressed in the heart and regulates cardiac remodelling through inhibition of hypertrophy and fibrosis. It is unknown if KLF15 expression is changed in CKD induced LVH, or whether expression is modulated by blood pressure reduction using angiotensin converting enzyme (ACE) inhibition.

Methods

CKD was induced in Sprague–Dawley rats by subtotal nephrectomy (STNx), and rats received vehicle (n = 10) or ACE inhibition (ramipril, 1 mg/kg/day, n = 10) for 4 weeks. Control, sham-operated rats (n = 9) received vehicle. Cardiac structure and function and expression of KLF15 were assessed.

Results

STNx caused impaired kidney function (P < 0.001), hypertension (P < 0.01), LVH (P < 0.001) and fibrosis (P < 0.05). LVH was associated with increased gene expression of hypertrophic markers, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP, P < 0.01) and connective tissue growth factor (CTGF) (P < 0.05). Cardiac KLF15 mRNA and protein expression were reduced (P < 0.05) in STNx and levels of the transcription regulator, GATA binding protein 4 were increased (P < 0.05). Ramipril reduced blood pressure (P < 0.001), LVH (P < 0.001) and fibrosis (P < 0.05), and increased cardiac KLF15 gene (P < 0.05) and protein levels (P < 0.01). This was associated with reduced ANP, BNP and CTGF mRNA (all P < 0.05).

Conclusion

This is the first evidence that loss of cardiac KLF15 in CKD induced LVH is associated with unchecked trophic and fibrotic signalling, and that ACE inhibition ameliorates loss of cardiac KLF15.

Low-Dose Levothyroxine Reduces Intrahepatic Lipid Content in Patients With Type 2 Diabetes Mellitus and NAFLD

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) is highly prevalent in patients with type 2 diabetes mellitus (T2DM) and associated with significant morbidity and mortality. Thyroid hormone (TH) increases β-oxidation of fatty acids and decreases intrahepatic lipid content (IHLC) in rodents with NAFLD.

OBJECTIVE

We investigated the possibility of low intrahepatic TH concentration in NAFLD and studied the effect of TH treatment in humans.

DESIGN/SETTING

This was a phase 2b single-arm study in six hospitals in Singapore. Intrahepatic thyroid hormone concentrations were measured in rats with induced NAFLD.

PATIENTS

Euthyroid patients with T2DM and steatosis measured by ultrasonography.

INTERVENTION

Levothyroxine was titrated to reach a thyroid-stimulating hormone level of 0.34 to 1.70 mIU/L before a 16-week maintenance phase.

MAIN OUTCOME MEASURES

The primary outcome measure was change in IHLC measured by proton magnetic resonance spectroscopy after treatment.

RESULTS

Twenty male patients were included in the per-protocol analysis [mean ± SD: age, 47.8 ± 7.8 years; body mass index (BMI), 30.9 ± 4.4 kg/m2; baseline IHLC, 13% ± 4%]. After treatment, IHLC was decreased 12% (±SEM, 26%) relative to baseline (absolute change, -2%; 95% CI, -3 to 0; P = 0.046). Small decreases in BMI (P = 0.044), visceral adipose tissue volume (P = 0.047), and subcutaneous adipose tissue volume (P = 0.045) were observed. No significant changes in glucose regulation or lipid profile occurred.

CONCLUSION

This study demonstrated the efficacy and safety of low-dose TH therapy for NAFLD in men. TH or TH analogs may be beneficial for this condition.

Angiotensin converting enzyme 2 activity and human atrial fibrillation: increased plasma angiotensin converting enzyme 2 activity is associated with atrial fibrillation and more advanced left atrial structural remodelling

Aim

Angiotensin converting enzyme 2 (ACE2) is an integral membrane protein whose main action is to degrade angiotensin II. Plasma ACE2 activity is increased in various cardiovascular diseases. We aimed to determine the relationship between plasma ACE2 activity and human atrial fibrillation (AF), and in particular its relationship to left atrial (LA) structural remodelling.

Methods and results

One hundred and three participants from a tertiary arrhythmia centre, including 58 with paroxysmal AF (PAF), 20 with persistent AF (PersAF), and 25 controls, underwent clinical evaluation, echocardiographic analysis, and measurement of plasma ACE2 activity. A subgroup of 20 participants underwent invasive LA electroanatomic mapping. Plasma ACE2 activity levels were increased in AF [control 13.3 (9.5-22.3) pmol/min/mL; PAF 16.9 (9.7-27.3) pmol/min/mL; PersAF 22.8 (13.7-33.4) pmol/min/mL, P = 0.006]. Elevated plasma ACE2 was associated with older age, male gender, hypertension and vascular disease, elevated left ventricular (LV) mass, impaired LV diastolic function and advanced atrial disease (P < 0.05 for all). Independent predictors of elevated plasma ACE2 activity were AF (P = 0.04) and vascular disease (P < 0.01). There was a significant relationship between elevated ACE2 activity and low mean LA bipolar voltage (adjusted R2 = 0.22, P = 0.03), a high proportion of complex fractionated electrograms (R2 = 0.32, P = 0.009) and a long LA activation time (R2 = 0.20, P = 0.04).

Conclusion

Plasma ACE2 activity is elevated in human AF. Both AF and vascular disease predict elevated plasma ACE2 activity, and elevated plasma ACE2 is significantly associated with more advanced LA structural remodelling.

Kruppel-Like Factor 15 Is Critical for the Development of Left Ventricular Hypertrophy

Left ventricular hypertrophy (LVH) is an independent risk factor for adverse cardiovascular events and is often present in patients with hypertension. Treatment to reduce blood pressure and regress LVH is key to improving health outcomes, but currently available drugs have only modest cardioprotective effects. Improved understanding of the molecular mechanisms involved in the development of LVH may lead to new therapeutic targets in the future. There is now compelling evidence that the transcription factor Kruppel-like factor 15 (KLF15) is an important negative regulator of cardiac hypertrophy in both experimental models and in man. Studies have reported that loss or suppression of KLF15 contributes to LVH, through lack of inhibition of pro-hypertrophic transcription factors and stimulation of trophic and fibrotic signaling pathways. This review provides a summary of the experimental and human studies that have investigated the role of KLF15 in the development of cardiac hypertrophy. It also discusses our recent paper that described the contribution of genetic variants in KLF15 to the development of LVH and heart failure in high-risk patients.

Left ventricular hypertrophy and cognitive function: a systematic review

Cognitive impairment is common in patients with hypertension. Left ventricular hypertrophy (LVH) is recognised as a marker of hypertension-related organ damage and is a strong predictor of coronary artery disease, heart failure and stroke. There is evidence that LVH is independently associated with cognitive impairment, even after adjustment for the presence of hypertension. We conducted a systematic review that examined cognitive impairment in adults with LVH. Independent searches were performed in Ovid MEDLINE, Ovid psycInfo and PubMed with the terms left ventricular hypertrophy and cognition. Seventy-three studies were identified when both searches were combined. After limiting the search to studies that were: (1) reported in English; (2) conducted in humans; (3) in adults aged 50 years and older; and (4) investigated the relationship between LVH and cognitive performance, nine papers were included in this systematic review. The majority of studies found an association between LVH and cognitive performance. Inspection of results indicated that individuals with LVH exhibited a lower performance in cognitive tests, when compared to individuals without LVH. Memory and executive functions were the cognitive domains that showed a specific vulnerability to the presence of LVH. A possible mechanism for the relationship between LVH and cognition is the presence of cerebral white matter damage. White matter lesions occur frequently in patients with LVH and may contribute to cognitive dysfunction. Together, the results of this review suggest that memory impairment and executive dysfunction are the cognitive domains that showed a particular association with the presence of LVH.

Development of Acute Decompensated Heart Failure Among Hospital Inpatients: Incidence, Causes and Outcomes

BACKGROUND

We aimed to investigate the incidence, precipitants, and outcomes of acute decompensated heart failure (ADHF) that develops during the inpatient stay.

METHODS

We undertook a case-control study in the medical, oncology, surgical, and orthopaedic wards of a tertiary referral hospital (February-May, 2016). Patients aged ≥18 years who developed ADHF during their inpatient stay were enrolled as cases. One control patient was matched to each case by age, gender, presenting complaint/surgery performed and co-morbidities. Multivariate regression was employed to determine variables associated with ADHF.

RESULTS

The incidence of ADHF was 1.0% of patients. Eighty cases were well-matched to 80 controls (p>0.05). ADHF precipitants comprised infection (30%), inappropriate intravenous (IV) fluid and medication management (23.8% and 8.8%, respectively), tachyarrhythmia (12.5%), ischaemic heart disease (8.8%), renal failure (1.3%), and other/unclear causes (15%). Three variables were associated with ADHF: not having English as the preferred language (OR 3.5, 95%CI 1.2-9.8), a history of ischaemic heart disease (OR 3.3, 95%CI 1.2-9.1), and the administration of >2000ml of IV fluid on the day before the ADHF (OR 8.3, 95%CI 1.5-48.0). The day before the ADHF, cases were administered significantly more IV fluids than controls (median 2,757.5 versus 975ml, p=0.001). Medication errors mostly related to failure to restart regular diuretics. Cases had significantly greater length of stay (median 15 versus 6 days, p<0.001) and mortality (12.5% versus 1.3%, p=0.01).

CONCLUSIONS

New onset ADHF is common and a substantial proportion of cases are iatrogenic. Cases experience significantly increased length of hospital stay, morbidity, and mortality.

Experimental and Human Evidence for Lipocalin-2 (Neutrophil Gelatinase-Associated Lipocalin [NGAL]) in the Development of Cardiac Hypertrophy and heart failure

BACKGROUND

Cardiac hypertrophy increases the risk of developing heart failure and cardiovascular death. The neutrophil inflammatory protein, lipocalin-2 (LCN2/NGAL), is elevated in certain forms of cardiac hypertrophy and acute heart failure. However, a specific role for LCN2 in predisposition and etiology of hypertrophy and the relevant genetic determinants are unclear. Here, we defined the role of LCN2 in concentric cardiac hypertrophy in terms of pathophysiology, inflammatory expression networks, and genomic determinants.

METHODS AND RESULTS

We used 3 experimental models: a polygenic model of cardiac hypertrophy and heart failure, a model of intrauterine growth restriction and Lcn2-knockout mouse; cultured cardiomyocytes; and 2 human cohorts: 114 type 2 diabetes mellitus patients and 2064 healthy subjects of the YFS (Young Finns Study). In hypertrophic heart rats, cardiac and circulating Lcn2 was significantly overexpressed before, during, and after development of cardiac hypertrophy and heart failure. Lcn2 expression was increased in hypertrophic hearts in a model of intrauterine growth restriction, whereas Lcn2-knockout mice had smaller hearts. In cultured cardiomyocytes, Lcn2 activated molecular hypertrophic pathways and increased cell size, but reduced proliferation and cell numbers. Increased LCN2 was associated with cardiac hypertrophy and diastolic dysfunction in diabetes mellitus. In the YFS, LCN2 expression was associated with body mass index and cardiac mass and with levels of inflammatory markers. The single-nucleotide polymorphism, rs13297295, located near LCN2 defined a significant cis-eQTL for LCN2 expression.

CONCLUSIONS

Direct effects of LCN2 on cardiomyocyte size and number and the consistent associations in experimental and human analyses reveal a central role for LCN2 in the ontogeny of cardiac hypertrophy and heart failure.

Does left ventricular hypertrophy affect cognition and brain structural integrity in type 2 diabetes? Study design and rationale of the Diabetes and Dementia (D2) study

BACKGROUND

Cognitive impairment is common in type 2 diabetes mellitus, and there is a strong association between type 2 diabetes and Alzheimer's disease. However, we do not know which type 2 diabetes patients will dement or which biomarkers predict cognitive decline. Left ventricular hypertrophy (LVH) is potentially such a marker. LVH is highly prevalent in type 2 diabetes and is a strong, independent predictor of cardiovascular events. To date, no studies have investigated the association between LVH and cognitive decline in type 2 diabetes. The Diabetes and Dementia (D2) study is designed to establish whether patients with type 2 diabetes and LVH have increased rates of brain atrophy and cognitive decline.

METHODS

The D2 study is a single centre, observational, longitudinal case control study that will follow 168 adult patients aged >50 years with type 2 diabetes: 50% with LVH (case) and 50% without LVH (control). It will assess change in cardiovascular risk, brain imaging and neuropsychological testing between two time-points, baseline (0 months) and 24 months. The primary outcome is brain volume change at 24 months. The co-primary outcome is the presence of cognitive decline at 24 months. The secondary outcome is change in left ventricular mass associated with brain atrophy and cognitive decline at 24 months.

DISCUSSION

The D2 study will test the hypothesis that patients with type 2 diabetes and LVH will exhibit greater brain atrophy than those without LVH. An understanding of whether LVH contributes to cognitive decline, and in which patients, will allow us to identify patients at particular risk.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ( ACTRN12616000546459 ), date registered, 28/04/2016.

Genetic Variation in Kruppel like Factor 15 Is Associated with Left Ventricular Hypertrophy in Patients with Type 2 Diabetes: Discovery and Replication Cohorts

Left ventricular (LV) hypertrophy (LVH) is a heritable trait that is common in type 2 diabetes and is associated with the development of heart failure. The transcriptional factor Kruppel like factor 15 (KLF15) is expressed in the heart and acts as a repressor of cardiac hypertrophy in experimental models. This study investigated if KLF15 gene variants were associated with LVH in type 2 diabetes. In stage 1 of a 2-stage approach, patients with type 2 diabetes and no known cardiac disease were prospectively recruited for a transthoracic echocardiographic assessment (Melbourne Diabetes Heart Cohort) (n = 318) and genotyping of two KLF15 single nucleotide polymorphisms (SNPs) (rs9838915, rs6796325). In stage 2, the association of KLF15 SNPs with LVH was investigated in the Genetics of Diabetes Audit and Research in Tayside Scotland (Go-DARTS) type 2 diabetes cohort (n = 5631). The KLF15 SNP rs9838915 A allele was associated in a dominant manner with LV mass before (P = 0.003) and after (P = 0.001) adjustment for age, gender, body mass index (BMI) and hypertension, and with adjusted septal (P < 0.0001) and posterior (P = 0.004) wall thickness. LVH was present in 35% of patients. Over a median follow up of 5.6 years, there were 22 (7%) first heart failure hospitalizations. The adjusted risk of heart failure hospitalization was 5.5-fold greater in those with LVH and the rs9838915 A allele compared to those without LVH and the GG genotype (hazard ratio (HR) 5.5 (1.6–18.6), P = 0.006). The association of rs9838915 A allele with LVH was replicated in the Go-DARTS cohort. We have identified the KLF15 SNP rs9838915 A allele as a marker of LVH in patients with type 2 diabetes, and replicated these findings in a large independent cohort. Studies are needed to characterize the functional importance of these results, and to determine if the SNP rs9838915 A allele is associated with LVH in other high risk patient cohorts.

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KLF15 SNP rs9838915 A allele is associated with increased LV mass in patients with 2 diabetes.

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KLF15 SNP rs9838915 predicts incident heart failure hospitalization.

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Genotyping KLF15 SNP rs9838915 allowed more precise stratification of the risk of heart failure hospitalization.

Left ventricular hypertrophy (LVH) is a heritable trait that is common in patients with diabetes. The Kruppel like factor 15 (KLF15) is expressed in the heart and acts as a repressor of cardiac hypertrophy and fibrosis. Our study provides evidence that genetic variation in KLF15 is associated with LVH in patients with type 2 diabetes and these findings were then replicated in an independent cohort of patients with type 2 diabetes. The KLF15 genetic variant was also associated with first heart failure hospitalization. These findings add to our understanding of the molecular mechanisms that contribute to increased LV mass.

Adverse cardiac effects of exogenous angiotensin 1-7 in rats with subtotal nephrectomy are prevented by ACE inhibition

We previously reported that exogenous angiotensin (Ang) 1–7 has adverse cardiac effects in experimental kidney failure due to its action to increase cardiac angiotensin converting enzyme (ACE) activity. This study investigated if the addition of an ACE inhibitor (ACEi) to Ang 1–7 infusion would unmask any beneficial effects of Ang 1–7 on the heart in experimental kidney failure. Male Sprague–Dawley rats underwent subtotal nephrectomy (STNx) and were treated with vehicle, the ACEi ramipril (oral 1mg/kg/day), Ang 1–7 (subcutaneous 24 μg/kg/h) or dual therapy (all groups, n = 12). A control group (n = 10) of sham-operated rats were also studied. STNx led to hypertension, renal impairment, cardiac hypertrophy and fibrosis, and increased both left ventricular ACE2 activity and ACE binding. STNx was not associated with changes in plasma levels of ACE, ACE2 or angiotensin peptides. Ramipril reduced blood pressure, improved cardiac hypertrophy and fibrosis and inhibited cardiac ACE. Ang 1–7 infusion increased blood pressure, cardiac interstitial fibrosis and cardiac ACE binding compared to untreated STNx rats. Although in STNx rats, the addition of ACEi to Ang 1–7 prevented any deleterious cardiac effects of Ang 1–7, a limitation of the study is that the large increase in plasma Ang 1–7 with ramipril may have masked any effect of infused Ang 1–7.

Arylene Azo p-Hydroxy Benzoic Acid–Formaldehyde Oligomer Dyes

A series of oligomeric azo dyes has been synthesized by coupling various aromatic diazonium salts to p-hydroxy benzoic acid–formaldehyde ( p-HBAF) oligomer. They were evaluated in terms of their softening points, yields, colour, UV–visible spectra, IR spectra and PMR spectra. Dyeing on wool and nylon resulted in yellow to red shades having moderate to good fastness to light and good to very good fastness to washing.

The Receptor for Advanced Glycation End Products (RAGE) Is Associated with Persistent Atrial Fibrillation

Objective

Upregulation of the receptor for advanced glycation end products (RAGE) has been proposed as a pathophysiological mechanism underlying the development of atrial fibrillation (AF). We sought to investigate if soluble RAGE levels are associated with AF in Caucasian patients.

Methods

Patients (n = 587) were prospectively recruited and serum levels of soluble RAGE (sRAGE) and endogenous secretory RAGE (esRAGE) measured. The patients included 527 with sinus rhythm, 32 with persistent AF (duration >7 days, n = 32) and 28 with paroxysmal AF (duration <7 days, n = 28).

Results

Patients with AF were older and had a greater prevalence of heart failure than patients in sinus rhythm. Circulating RAGE levels were higher in patients with persistent AF [median sRAGE 1190 (724–2041) pg/ml and median esRAGE 452 (288–932) pg/ml] compared with paroxysmal AF [sRAGE 799 (583–1033) pg/ml and esRAGE 279 (201–433) pg/ml, p ≤ 0.01] or sinus rhythm [sRAGE 782 (576–1039) pg/ml and esRAGE 289 (192–412) pg/ml, p < 0.001]. In multivariable logistic regression analysis, independent predictors of persistent AF were age, heart failure, sRAGE [odds ratio 1.1 per 100 pg/ml, 95% confidence interval (CI) 1.0–1.1, p = 0.001] and esRAGE [odds ratio 1.3 per 100 pg/ml, 95% CI 1.1–1.4, p < 0.001]. Heart failure and age were the only independent predictors of paroxysmal AF. In AF patients, sRAGE [odds ratio 1.1 per 100 pg/ml, 95% CI 1.1–1.2, p = 0.007] and esRAGE [odds ratio 1.3 per 100 pg/ml, 95% CI 1.0–1.5, p = 0.017] independently predicted persistent compared with paroxysmal AF.

Conclusions

Soluble RAGE is elevated in Caucasian patients with AF, and both sRAGE and esRAGE predict the presence of persistent AF.

Diminazene Aceturate Improves Cardiac Fibrosis and Diastolic Dysfunction in Rats with Kidney Disease

Angiotensin converting enzyme (ACE) 2 is a negative regulator of the renin angiotensin system (RAS) through its role to degrade angiotensin II. In rats with subtotal nephrectomy (STNx), adverse cardiac remodelling occurs despite elevated cardiac ACE2 activity. We hypothesised that diminazene aceturate (DIZE), which has been described as having an off-target effect to activate ACE2, would have beneficial cardiac effects in STNx rats. STNx led to hypertension, diastolic dysfunction, left ventricular hypertrophy, cardiac fibrosis, and increased cardiac ACE, ACE2, Ang II and Ang 1-7 levels. Cardiac gene expression of ADAM17 was also increased. In STNx, two-weeks of subcutaneous DIZE (15mg/kg/d) had no effect on blood pressure but improved diastolic dysfunction and cardiac fibrosis, reduced ADAM17 mRNA and shifted the cardiac RAS balance to a cardioprotective profile with reduced ACE and Ang II. There was no change in cardiac ACE2 activity or in cardiac Ang 1-7 levels with DIZE. In conclusion, our results suggest that DIZE exerts a protective effect on the heart under the pathological condition of kidney injury. This effect was not due to improved kidney function, a fall in blood pressure or a reduction in LVH but was associated with a reduction in cardiac ACE and cardiac Ang II levels. As in vitro studies showed no direct effect of DIZE on ACE2 or ACE activity, the precise mechanism of action of DIZE remains to be determined.

Standard of Care for Neuropsychological Monitoring in Pediatric Neuro-Oncology: Lessons From the Children's Oncology Group (COG)

As the mortality of pediatric cancers has decreased, focus on neuropsychological morbidities of treatment sequelae have increased. Neuropsychological evaluations are essential diagnostic tools that assess cognitive functioning and neurobiological integrity. These tests provide vital information to support ongoing medical care, documenting cognitive morbidity and response to interventions. We frame standards for neuropsychological monitoring of pediatric patients with CNS malignancy or who received cancer-directed therapies involving the CNS and discuss billing for these services in the United States in the context of clinical research. We describe a cost-effective, efficient model of neuropsychological monitoring that may increases access to neuropsychological care.

MicroRNAs mediate the cardioprotective effect of angiotensin-converting enzyme inhibition in acute kidney injury

Cardiovascular disease, including cardiac hypertrophy, is common in patients with kidney disease and can be partially attenuated using blockers of the renin-angiotensin system (RAS). It is unknown whether cardiac microRNAs contribute to the pathogenesis of cardiac hypertrophy or to the protective effect of RAS blockade in kidney disease. Using a subtotal nephrectomy rat model of kidney injury, we investigated changes in cardiac microRNAs that are known to have direct target genes involved in the regulation of apoptosis, fibrosis, and hypertrophy. The effect of treatment with the angiotensin-converting enzyme (ACE) inhibitor ramipril on cardiac microRNAs was also investigated. Kidney injury led to a significant increase in cardiac microRNA-212 and microRNA-132 expression. Ramipril reduced cardiac hypertrophy, attenuated the increase in microRNA-212 and microRNA-132, and significantly increased microRNA-133 and microRNA-1 expression. There was altered expression of caspase-9, B cell lymphoma-2, transforming growth factor-β, fibronectin 1, collagen type 1A1, and forkhead box protein O3, which are all known to be involved in the regulation of apoptosis, fibrosis, and hypertrophy in cardiac cells while being targets for the above microRNAs. ACE inhibitor treatment increased expression of microRNA-133 and microRNA-1. The inhibitory action of ACE inhibitor treatment on increased cardiac NADPH oxidase isoform 1 expression after subtotal nephrectomy surgery suggests that inhibition of oxidative stress is also one of mechanism of ACE inhibitor-mediated cardioprotection. These finding suggests the involvement of microRNAs in the cardioprotective action of ACE inhibition in acute renal injury, which is mediated through an inhibitory action on profibrotic and proapoptotic target genes and stimulatory action on antihypertrophic and antiapoptotic target genes.

Usefulness of retinal microvascular endothelial dysfunction as a predictor of coronary artery disease

Endothelial dysfunction is a key feature of atherosclerosis. Retinal microvascular endothelial function can be assessed using noninvasive dynamic vessel imaging techniques. Whether it is impaired in subjects with coronary artery disease (CAD) is unknown. The aim of this study was to examine the relation of retinal microvascular endothelial function with CAD. Vascular studies were performed in 197 prospectively recruited subjects divided into 2 groups: those without CAD but ≥2 cardiovascular risk factors (non-CAD controls; n = 119) and those with stable CAD (n = 78). Retinal microvascular endothelial dysfunction was assessed by measuring retinal arteriolar and venular dilatation to flicker light, a nitric oxide-dependent phenomenon, expressed as percentage increase over baseline diameter. Fingertip pulse-volume amplitude was measured to calculate reactive hyperaemia index and brachial artery flow-mediated dilatation assessed as measures of peripheral microvascular and conduit vessel endothelial function, respectively. Mean retinal arteriolar dilatation was attenuated in patients with CAD compared with non-CAD controls (1.51 ± 1.51% vs 2.37 ± 1.95%, p = 0.001). Retinal arteriolar dilatation was independently associated with CAD after adjustment for age, gender, cardiovascular risk factors, and medication use (odds ratio 1.60, 95% confidence interval 1.14 to 2.25, p = 0.007). Reactive hyperaemia index and flow-mediated dilatation were not different. In conclusion, the capacity of retinal arterioles to dilate in response to flicker light is an independent predictor of the presence of CAD and suggests that retinal microvascular endothelial dysfunction is a marker for underlying CAD.

Bioadhesive films containing fluconazole for mucocutaneous candidiasis

Fluconazole is a broad spectrum antifungal agent that has been extensively applied for the management of oral, pharyngeal and cutaneous candidiasis. Fluconazole has a high volume of distribution (0.55–0.65 l/kg) and has systemic toxicity due to high drug-drug interaction. The present study focuses on the formulation of bioadhesive film as a controlled release carrier for fluconazole. The formulation was intended to provide localized delivery of fluconazole exclusively at the site of infection, thereby reducing its total dose and hence, dose-related toxicities. Bioadhesive films were prepared by solvent casting method using sodium alginate and polyvinyl alcohol alone as well as in various combinations. Prepared films were evaluated for physical characteristics like, weight and content uniformity, film thickness, swelling index, microenvironment pH and folding endurance. In vitro drug release, in vitro and ex vivo residence time, bioadhesive strength and skin irritation were also studied. Accelerated stability study was conducted on the optimized formulation as per ICH guidelines. Weight of all the films were not more than 20 mg. Thickness of the films ranged between 0.09 to 0.15 mm whereas swelling indices showed a high extent of variation. Films composed of polyvinyl alcohol alone provided a swelling index of 6%. Bioadhesive strength was found to be more than 18 g. Microenvironment pH was near to 7.0 for most of the formulations. Ex vivo residence time of optimized batch was more than 5 h and it provided controlled drug release up to 8 h. As revealed in FT-IR and DSC studies, drug was found to be compatible with the excipients used in this study.

Pharmacology of AMG 181, a human anti-α4 β7 antibody that specifically alters trafficking of gut-homing T cells

BACKGROUND AND PURPOSE

AMG 181 is a human anti-α4 β7 antibody currently in phase 1 and 2 trials in subjects with inflammatory bowel diseases. AMG 181 specifically targets the α4 β7 integrin heterodimer, blocking its interaction with mucosal addressin cell adhesion molecule-1 (MAdCAM-1), the principal ligand that mediates α4 β7 T cell gut-homing.

EXPERIMENTAL APPROACH

We studied the in vitro pharmacology of AMG 181, and the pharmacokinetics and pharmacodynamics of AMG 181 after single or weekly i.v. or s.c. administration in cynomolgus monkeys for up to 13 weeks.

KEY RESULTS

AMG 181 bound to α4 β7 , but not α4 β1 or αE β7 , and potently inhibited α4 β7 binding to MAdCAM-1 (but not vascular cell adhesion molecule-1) and thus inhibited T cell adhesion. Following single i.v. administration, AMG 181 Cmax was dose proportional from 0.01 to 80 mg·kg(-1) , while AUC increased more than dose proportionally. Following s.c. administration, dose-proportional exposure was observed with single dose ranging from 5 to 80 mg·kg(-1) and after 13 weekly doses at levels between 20 and 80 mg·kg(-1) . AMG 181 accumulated two- to threefold after 13 weekly 80 mg·kg(-1) i.v. or s.c. doses. AMG 181 had an s.c. bioavailability of 80%. The linear elimination half-life was 12 days, with a volume of distribution close to the intravascular plasma space. The mean trend for the magnitude and duration of AMG 181 exposure, immunogenicity, α4 β7 receptor occupancy and elevation in gut-homing CD4+ central memory T cell count displayed apparent correlations.

CONCLUSIONS AND IMPLICATIONS

AMG 181 has in vitro pharmacology, and pharmacokinetic/pharmacodynamic and safety characteristics in cynomolgus monkeys that are suitable for further investigation in humans.

From gene to protein-experimental and clinical studies of ACE2 in blood pressure control and arterial hypertension

Hypertension is a major risk factor for stroke, coronary events, heart and renal failure, and the renin-angiotensin system (RAS) plays a major role in its pathogenesis. Within the RAS, angiotensin converting enzyme (ACE) converts angiotensin (Ang) I into the vasoconstrictor Ang II. An “alternate” arm of the RAS now exists in which ACE2 counterbalances the effects of the classic RAS through degradation of Ang II, and generation of the vasodilator Ang 1-7. ACE2 is highly expressed in the heart, blood vessels, and kidney. The catalytically active ectodomain of ACE2 undergoes shedding, resulting in ACE2 in the circulation. The ACE2 gene maps to a quantitative trait locus on the X chromosome in three strains of genetically hypertensive rats, suggesting that ACE2 may be a candidate gene for hypertension. It is hypothesized that disruption of tissue ACE/ACE2 balance results in changes in blood pressure, with increased ACE2 expression protecting against increased blood pressure, and ACE2 deficiency contributing to hypertension. Experimental hypertension studies have measured ACE2 in either the heart or kidney and/or plasma, and have reported that deletion or inhibition of ACE2 leads to hypertension, whilst enhancing ACE2 protects against the development of hypertension, hence increasing ACE2 may be a therapeutic option for the management of high blood pressure in man. There have been relatively few studies of ACE2, either at the gene or the circulating level in patients with hypertension. Plasma ACE2 activity is low in healthy subjects, but elevated in patients with cardiovascular risk factors or cardiovascular disease. Genetic studies have investigated ACE2 gene polymorphisms with either hypertension or blood pressure, and have produced largely inconsistent findings. This review discusses the evidence regarding ACE2 in experimental hypertension models and the association between circulating ACE2 activity and ACE2 polymorphisms with blood pressure and arterial hypertension in man.

Prevalence, predictors and evolution of echocardiographically defined cardiac abnormalities in adults with type 1 diabetes: an observational cohort study

AIMS/HYPOTHESIS

The aims of this observational study were to determine the prevalence and predictors of an abnormal echocardiogram in adults with type 1 diabetes, and to assess the evolution of changes in a subset of subjects.

METHODS

Cardiac function and structure were prospectively investigated by comprehensive transthoracic echocardiographic techniques in asymptomatic adults with type 1 diabetes seen in the ambulatory care setting.

RESULTS

We recruited 136 subjects (mean age 39 years, SD 14 years) with a median diabetes duration of 21 years [25(th), 75(th) interquartile range; 11, 29]. An abnormal echocardiogram was present in 29% of subjects; diastolic dysfunction in 69%, left ventricular hypertrophy in 38% and systolic dysfunction in 10%. The independent predictors of an abnormal echocardiogram were age, with a 9-fold increase in those ≥40 years (OR 9.40 [95% CI 2.68-33.04], P <0.0001), and increased body mass index (BMI), with a 17% increase in risk (P=0.04). A second echocardiogram was available in 65 subjects (3.8±1.7 years later). The results showed that one in five with a normal first study had developed an abnormal second study, mainly diastolic dysfunction, with age being the only independent predictor of progression (P=0.006).

CONCLUSIONS/INTERPRETATION

Subclinical echocardiographic abnormalities are common in asymptomatic type 1 diabetes adults, and changes are progressive. The addition of an echocardiogram to complication surveillance programs in those with type 1 diabetes aged ≥40 years may represent a cost-effective way to screen for, and aggressively treat, occult cardiac disease.

Emerging markers in cardiovascular disease: where does angiotensin-converting enzyme 2 fit in?

The renin-angiotensin system plays a major role in the pathophysiology of cardiovascular disease (CVD). The enzyme angiotensin-converting enzyme (ACE) converts angiotensin (Ang) I into the vasoconstrictor AngII and was thought, until recently, to be the main effector of the system. The enzyme ACE2, discovered in 2000, can counterbalance the effects of ACE through degradation of AngII and generation of Ang-(1-7). Angiotensin-converting enzyme 2 is abundantly expressed in the heart and localized to the endothelial cells of coronary vessels and smooth muscle cells. Its catalytically active ectodomain undergoes shedding, resulting in ACE2 in the circulation. There are 10 studies to date that have measured circulating ACE2 activity in humans, including in healthy subjects and those with heart failure, Type 1 diabetes, implantable cardioverter/defibrillator, elderly subjects undergoing emergency orthopaedic surgery and kidney transplant patients. The results suggest that circulating ACE2 activity may be a marker of CVD, with low levels in healthy individuals and increased levels in those with cardiovascular risk factors or disease. Whether increased plasma ACE2 activity reflects increased synthesis from tissue ACE2 mRNA or increased shedding of tissue ACE2 remains to be determined. Angiotensin-converting enzyme 2 is located on the X-chromosome and circulating ACE2 levels are higher in men than in women. Large clinical studies in CVD are needed to more precisely clarify the role of ACE2 as a biomarker of CVD, determine the prognostic significance of circulating ACE2 activity and assess whether the measurement of ACE2 will improve CVD risk prediction.

Prognostic utility of hypothermic machine perfusion in deceased donor renal transplantation

Pulsatile pump perfusion of kidney transplants is known to decrease delayed graft function (DGF) and improve 1 year graft survival when compared to static cold preservation. Kidneys with better flow and resistance parameters on perfusion are likely to have a better post transplant function. These parameters are commonly used to evaluate kidneys being considered for transplantation. This study assesses the time frame for a kidney within which it reaches optimal perfusion parameters. All kidneys pumped between 5/2006 and 9/2009 on a Lifeport© kidney transporter at our local organ procurement agency were studied. 190 kidneys were evaluated and then divided into two groups based on whether terminal flows increased or declined after prolonged perfusion. All kidneys were assessed for changes in flow (F), resistance (R) and temperature at 15 minute intervals. Discards, DGF and one year graft survival were noted. The Student paired t test and Chi-square analysis were used to compare data. A multiple logistic regression analysis was performed to study independent predictors of DGF on pump perfusion.

RESULTS

For all kidneys, the mean initial flow was 59 ± 35 mL/min which improved to an average flow of 128 ± 38 mL/min with continued perfusion. The maximal flow and terminal flows were 148 ± 51 and 135 ± 38 mL/min respectively. The flows at 2, 4, and 6 hours was 125 ± 41, 128 ± 42 and 130 ± 39 mL/min respectively. Kidneys that improved on continued perfusion had a significantly lower discard rate (20 vs 34% p < 0.05), but a higher incidence of DGF (64 vs 39%, P < .05). One year graft loss (death censored) was comparable in the two groups. (4/42 vs. 3/33, P = .94). Resistance at 2, 4, and 6 hours was predictive of DGF, as was donor anoxia and cerebrovascular accident (CVA) as the cause of death.

CONCLUSIONS

Kidneys on pulsatile pump perfusion tend to show improved flows and decreased resistance over time. The average flow for a kidney is reached by 2 hours. Those kidneys that start with lower flow rates that improve after 2 hours with continued perfusion are less likely to be discarded but are still associated with a greater incidence of delayed graft function. Resistance at 2 hours predicts DGF while initial resistance predicts one year graft survival.