BackgroundAging is associated with increased levels of reactive oxygen species and inflammation that disrupt proteostasis and mitochondrial function and leads to organism-wide frailty later in life. ARA290 (cibinetide), an 11-aa non-hematopoietic peptide sequence within the cardioprotective domain of erythropoietin, mediates tissue protection by reducing inflammation and fibrosis. Age-associated cardiac inflammation is linked to structural and functional changes in the heart, including mitochondrial dysfunction, impaired proteostasis, hypertrophic cardiac remodeling, and contractile dysfunction. Can ARA290 ameliorate these age-associated cardiac changes and the severity of frailty in advanced age?MethodsWe conducted an integrated longitudinal (n = 48) and cross-sectional (n = 144) 15 months randomized controlled trial in which 18-month-old Fischer 344 x Brown Norway rats were randomly assigned to either receive chronic ARA290 treatment or saline. Serial echocardiography, tail blood pressure and body weight were evaluated repeatedly at 4-month intervals. A frailty index was calculated at the final timepoint (33 months of age). Tissues were harvested at 4-month intervals to define inflammatory markers and left ventricular tissue remodeling. Mitochondrial and myocardial cell health was assessed in isolated left ventricular myocytes. Kaplan–Meier survival curves were established. Mixed ANOVA tests and linear mixed regression analysis were employed to determine the effects of age, treatment, and age-treatment interactions.ResultsChronic ARA290 treatment mitigated age-related increases in the cardiac non-myocyte to myocyte ratio, infiltrating leukocytes and monocytes, pro-inflammatory cytokines, total NF-κB, and p-NF-κB. Additionally, ARA290 treatment enhanced cardiomyocyte autophagy flux and reduced cellular accumulation of lipofuscin. The cardiomyocyte mitochondrial permeability transition pore response to oxidant stress was desensitized following chronic ARA290 treatment. Concurrently, ARA290 significantly blunted the age-associated elevation in blood pressure and preserved the LV ejection fraction. Finally, ARA290 preserved body weight and significantly reduced other markers of organism-wide frailty at the end of life.ConclusionAdministration of ARA290 reduces cell and tissue inflammation, mitigates structural and functional changes within the cardiovascular system leading to amelioration of frailty and preserved healthspan.

Objective: To determine whether a novel anti-inflammatory, erythropoietin-derived synthetic peptide, ARA290, can improve healthspan and delay deteriorations in heart function.

BackgroundChronic inflammation is linked to age‐associated declines in heart structure and function that contribute to increased risks for cardiovascular mortality and frailty, a state of high vulnerability to adverse health outcomes, and to reduced healthspan.ObjectiveTo determine whether a novel anti‐inflammatory, erythropoietin‐derived synthetic peptide, ARA290, can improve healthspan and delay deteriorations in heart function.Methods18 mo Fischer 344 × Brown Norway male rats (n = 50) were randomized to bi‐weekly injections of ARA290 or saline. Body weight (BW) was recorded every 2 weeks until death. Echocardiograms (ECHO), to measure ejection fraction (EF), and electrocardiograms (ECG), to measure heart rate (HR) before (BHR) and during a double autonomic blockade (IHR), were performed at 18, 22, 26, 30, and 33 mo, when a 33‐item frailty index (FI), scored on a scale of 0 to 1 (least to most frail), assessed health deficits in integument, musculoskeletal, vestibulocochlear, ocular, neurological, digestive, and respiratory systems. Linear mixed effects models assessed changes in cardiac markers over time, and joint models predicted the overall risk of death based on those changes and survival data.ResultsARA290 slowed the decline in BHR that accompanied aging (p < 0.03): between 18 and 33 mo BHR decreased from 327 to 276 beats per minute (BPM) in ARA290 and 314 to 261 BPM in the control; between 27 and 33 mo BHR plateaued in ARA290 but continued to decline in the control. IHR declined non‐linearly from 254 BPM to 240 BPM between 18 and 33 mo (p < 0.003), but did not differ by treatment. The difference between BHR and IHR (ΔHR), an index of autonomic modulation on HR, declined from 58 to 17 BPM in the control and from 73 to 38 BPM in ARA290 between 18 and 33 mo. Between 22 and 33 mo ΔHR was preserved in ARA290, but not control(p < 0.02). EF in ARA290 declined from 82.4% to 76.8% at a rate of 0.469% per month slower than the control, in which EF declined from 84.6% to 70.3% (p < 0.005). At 33 months EF was 7.5% greater in ARA290 (p < 0.004). BW decreased from 534 to 486 g between 25.5 and 33.0 months in ARA290 and from 529 to 442 g between 24.3 and 33.0 months in the control. ARA290 retarded the reduction in BW by 0.04 grams/month2 (p < 0.02). FI score was significantly lower in ARA290 (0.22) compared to the control (0.30) (p < 0.001). Joint model predictions show higher risks of death by 1.2% for a 1 BPM decrease in BHR (p < 0.0001), by 1.5% for a 1 BPM decrease in IHR (p < 0.0001), by 1.1% for a 1 BPM decrease in ΔHR (p < 0.12), and by 11.9% for a 1% decrease in EF (p < 0.0001).ConclusionsReduced frailty of ARA290 in advanced age is consistent with improved healthspan. Concurrent ARA290 preservation in autonomic modulation of HR and EF are reflected by changes in BHR, IHR, ΔHR, and EF with age. Because a unit decrease in any of these markers predicted significantly higher risks for mortality, the impact of ARA290 on cardiac aging may contribute to the observed improvement in healthspan.Support or Funding InformationResearch was supported by the National Institute of Health/National Institute on Aging Intramural Researc program.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A mutation within the gamma 2 subunit (PRKAG2) of AMP protein kinase (AMPK) conferring constitutive activity results in a decreased heart rate (unpublished data); in contrast, mice null for the PRAKG2 gene have an increased heart rate and are unable to achieve a resting bradycardia following endurance training. Thus, it has become apparent that the gamma 2 subunit is essential for chronically reducing the heart rate at rest. Recently it has been demonstrated that endurance training induces alterations intrinsic to pacemaker cell function, where extensive classical evidence indicates that endurance training affects heart rate via increased vagal and decreased sympathetic tone. Autonomic influence on heart rate can be traced back to characteristic changes in time and frequency domain measures of heart rate variability. We tested the hypothesis that: (1) constitutively active AMPK, in addition to reducing the intrinsic heart rate, also modulates autonomic input to the heart, and (2) AMPK-dependent changes in autonomic activity are not only associated with characteristic changes in basal HRV, but also to variability intrinsic to sinoatrial nodal cells devoid of autonomic input. We show via telemetry, that unanesthetized mice homozygous for constitutively active AMPK display (1) a basal heart rate 50 BPM lower than wildtype littermates, (2) changes in rhythmicity, as noted by a 25% decrease in the coefficient of variation, (3) altered autonomic input, as seen with a two fold increase in very low frequency and corresponding decreases in both high and low frequency power, (4) an intrinsic heart rate approximately 65 BPM lower than control mice, and (5) a 30% increase in intrinsic variability. These findings provide the first in vivo evidence of AMPK's effects upon heart rate, heart rate variability, autonomic input in PRAKG2 associated mutations.