Association of low diastolic blood pressure with cardiovascular outcomes and all-cause mortality: A meta-analysis

BACKGROUND

Reduction of diastolic blood pressure (DBP) below 70 mmHg may decrease perfusion to the heart and worsen cardiovascular (CV) outcomes.

AIMS

Explore the association between low DBP and CV outcomes.

METHODS

We searched the online databases until August 2023 for studies reporting the risk of all-cause mortality (ACM) or CV outcomes in patients with low versus normal DBP (70-80mm Hg).

RESULTS

Inclusion of 10 studies (n = 1,998,223 patients) found that a mean achieved DBP < 60 mmHg was associated with an increased risk of all-cause mortality (HR 1.48; 95 % CI [1.26-1.74]), especially in patients with pre-existing CV disease. It was also associated to a higher risk of major adverse cardiovascular events (HR 1.84; [1.28-2.65]) and myocardial infarction (HR 1.49; [1.13-1.97]). A DBP of 60-69 mmHg was associated with an increased risk of all-cause mortality (HR 1.11; [1.03-1.20]).

CONCLUSION

Reduction of DBP, particularly below 60 mmHg, is associated with increased risk of ACM.

Age-Related Differences in the Contribution of Systolic Blood Pressure and Biomarkers to Cardiovascular Disease Risk Prediction: The Atherosclerosis Risk in Communities (ARIC) Study

We sought to determine how biomarkers known to be associated with hypertension-induced end-organ injury complement the use of systolic blood pressure (SBP) for cardiovascular disease (CVD) risk prediction at different ages. Using data from visits 2 (1990 to 1992) and 5 (2011 to 2013) of the Atherosclerosis Risk in Communities (ARIC) study, 3 models were used to predict CVD (composite of coronary heart disease, stroke, and heart failure). Model A included traditional risk factors (TRFs) except SBP, model B-TRF plus SBP, and model C-TRF plus biomarkers (high-sensitivity troponin T [hsTnT] and N-terminal pro-B-type natriuretic peptide [NT-proBNP]). Harrel's C-statistics were used to assess risk discrimination for CVD comparing models B and A and C and B. At visit 2, the addition of SBP to TRF (model B vs model A) significantly improved the C-statistic (∆C-statistic, 95% confidence interval 0.010, 0.007 to 0.013) whereas the addition of hsTnT to TRF (model C vs model B) decreased the C-statistic (∆C-statistic -0.0038, -0.0075 to -0.0001) compared with SBP. At visit 5, the addition of SBP to TRF did not significantly improve the C-statistic (∆C-statistic 0.001, -0.002 to 0.005) whereas the addition of both hsTnT and NT-proBNP to TRF significantly improved the C-statistic compared with SBP (∆C-statistic 0.028, 0.015 to 0.041 and 0.055, 0.036 to 0.074, respectively). In summary, the incremental value of SBP for CVD risk prediction diminishes with age whereas the incremental value of hsTnT and NT-proBNP increases with age.

Impact of Geroscience on Therapeutic Strategies for Older Adults With Cardiovascular Disease: JACC Scientific Statement

Geroscience posits that cardiovascular disease (CVD) and other chronic diseases result from progressive erosion of the effectiveness of homeostatic mechanisms that oppose age-related accumulation of molecular damage. This hypothetical common root to chronic diseases explains why patients with CVD are often affected by multimorbidity and frailty and why older age negatively affects CVD prognosis and treatment response. Gerotherapeutics enhance resilience mechanisms that counter age-related molecular damage to prevent chronic diseases, frailty, and disability, thereby extending healthspan. Here, we describe the main resilience mechanisms of mammalian aging, with a focus on how they can affect CVD pathophysiology. We next present novel gerotherapeutic approaches, some of which are already used in management of CVD, and explore their potential to transform care and management of CVD. The geroscience paradigm is gaining traction broadly in medical specialties, with potential to mitigate premature aging, reduce health care disparities, and improve population healthspan.

Cardiovascular hemodynamics in mice with tumor necrosis factor receptor-associated factor 2 mediated cytoprotection in the heart

Introduction

Many studies in mice have demonstrated that cardiac-specific innate immune signaling pathways can be reprogrammed to modulate inflammation in response to myocardial injury and improve outcomes. While the echocardiography standard parameters of left ventricular (LV) ejection fraction, fractional shortening, end-diastolic diameter, and others are used to assess cardiac function, their dependency on loading conditions somewhat limits their utility in completely reflecting the contractile function and global cardiovascular efficiency of the heart. A true measure of global cardiovascular efficiency should include the interaction between the ventricle and the aorta (ventricular-vascular coupling, VVC) as well as measures of aortic impedance and pulse wave velocity.

Methods

We measured cardiac Doppler velocities, blood pressures, along with VVC, aortic impedance, and pulse wave velocity to evaluate global cardiac function in a mouse model of cardiac-restricted low levels of TRAF2 overexpression that conferred cytoprotection in the heart.

Results

While previous studies reported that response to myocardial infarction and reperfusion was improved in the TRAF2 overexpressed mice, we found that TRAF2 mice had significantly lower cardiac systolic velocities and accelerations, diastolic atrial velocity, aortic pressures, rate-pressure product, LV contractility and relaxation, and stroke work when compared to littermate control mice. Also, we found significantly longer aortic ejection time, isovolumic contraction and relaxation times, and significantly higher mitral early/atrial ratio, myocardial performance index, and ventricular vascular coupling in the TRAF2 overexpression mice compared to their littermate controls. We found no significant differences in the aortic impedance and pulse wave velocity.

Discussion

While the reported tolerance to ischemic insults in TRAF2 overexpression mice may suggest enhanced cardiac reserve, our results indicate diminished cardiac function in these mice.

Supplementing Glycine and N-Acetylcysteine (GlyNAC) in Older Adults Improves Glutathione Deficiency, Oxidative Stress, Mitochondrial Dysfunction, Inflammation, Physical Function, and Aging Hallmarks: A Randomized Clinical Trial

BACKGROUND

Elevated oxidative stress (OxS), mitochondrial dysfunction, and hallmarks of aging are identified as key contributors to aging, but improving/reversing these defects in older adults (OA) is challenging. In prior studies, we identified that deficiency of the intracellular antioxidant glutathione (GSH) could play a role and reported that supplementing GlyNAC (combination of glycine and N-acetylcysteine [NAC]) in aged mice improved GSH deficiency, OxS, mitochondrial fatty-acid oxidation (MFO), and insulin resistance (IR). To test whether GlyNAC supplementation in OA could improve GSH deficiency, OxS, mitochondrial dysfunction, IR, physical function, and aging hallmarks, we conducted a placebo-controlled randomized clinical trial.

METHODS

Twenty-four OA and 12 young adults (YA) were studied. OA was randomized to receive either GlyNAC (N = 12) or isonitrogenous alanine placebo (N = 12) for 16-weeks; YA (N = 12) received GlyNAC for 2-weeks. Participants were studied before, after 2-weeks, and after 16-weeks of supplementation to assess GSH concentrations, OxS, MFO, molecular regulators of energy metabolism, inflammation, endothelial function, IR, aging hallmarks, gait speed, muscle strength, 6-minute walk test, body composition, and blood pressure.

RESULTS

Compared to YA, OA had GSH deficiency, OxS, mitochondrial dysfunction (with defective molecular regulation), inflammation, endothelial dysfunction, IR, multiple aging hallmarks, impaired physical function, increased waist circumference, and systolic blood pressure. GlyNAC (and not placebo) supplementation in OA improved/corrected these defects.

CONCLUSION

GlyNAC supplementation in OA for 16-weeks was safe and well-tolerated. By combining the benefits of glycine, NAC and GSH, GlyNAC is an effective nutritional supplement that improves and reverses multiple age-associated abnormalities to promote health in aging humans. Clinical Trials Registration Number: NCT01870193.

Sex-specific Phenotypes in the Aging Mouse Heart and Consequences for Chronic Fibrosis

The incidence of diastolic dysfunction increases with age in both humans and mice. This is characterized by increased passive stiffness and slower relaxation of the left ventricle. The stiffness arises at least partially from progressively increased interstitial collagen deposition due to highly secretory fibroblasts. In the past, we demonstrated that AMPK activation via the drug Aicar in middle-aged mice reduced adverse remodeling after myocardial infarction. Therefore as an attempt to normalize the fibroblast phenotype, we used 21 month-old male and female mice and treated them with Aicar (0.166 mg/g of body weight) where each mouse was followed in a functional study over a 3-month period. We found sex-related differences in extracellular matrix (ECM) composition as well as heart function indices at baseline, which were further accentuated by Aicar treatment. Aicar attenuated the age-related increase in left atrial volume (LAV, an indicator of diastolic dysfunction) in female but not in male hearts which was associated with reduced collagen deposition in the old female heart, and reduced the transcription factor Gli1 expression in cardiac fibroblasts. We further demonstrated that collagen synthesis was dependent on Gli1, which is a target of AMPK-mediated degradation. By contrast, Aicar had a minor impact on cardiac fibroblasts in the old male heart due to blunted AMPK phosphorylation. Hence it did not significantly improve old male heart function indices. In conclusion, we demonstrated that male and female hearts are phenotypically different, and sex-specific differences need to be considered when analyzing the response to pharmacological intervention.

Abstract 92: Delirium In-hospital Leads To Poor Short And Long-term Outcomes Among Treated And Non-treated Patients With Acute Ischemic Stroke

Background: Delirium in-hospital (DIH) is common among the critically ill. However, DIH incidence and outcomes are not well characterized among ischemic stroke (IS) patients, particularly those treated with intravenous tissue plasminogen activator (tPA) and / or mechanical thrombectomy (MT).

Methods: Utilizing data from a healthcare system with standardized delirium screening protocols, DIH was determined by a positive 4AT / CAM-ICU screen or diagnosis codes. IS patients with tPA or MT were flagged and a subset with available 90-day modified Rankin Scale (mRS) were analyzed for shifts in mRS scores associated with DIH, via ordinal logistic regression models adjusted for age, stroke severity, tPA or MT, Charlson Comorbidity Index [CCI], prior stroke and sepsis / infections. Common odds ratios (OR) and 95% confidence intervals (CI) are reported.

Results: Between May 2016 and June 2021, IS was the primary discharge diagnosis in 12,415 encounters (10,878 unique patients). DIH was documented in 41.6% of IS encounters, compared to 20.0% of non-IS encounters. Stroke-DIH patients (vs no-DIH Stroke) were older (median: 75 vs 65 years), more frequently female (53.3% vs 48.7%), with higher comorbidity burden (median CCI: 7 vs 5), longer hospital stays (median: 6 vs 3 days), higher in-hospital mortality (3.1% vs 0.5%), and fewer home discharges (36.2% vs 75.2%). Among a sub-cohort of 2,785 IS patients with 90-day mRS, fully adjusted model indicated lower mRS (OR, CI: 0.48, 0.41-0.57) for those with tPA or MT, and worse outcomes for DIH patients (OR, CI: 2.70, 2.26-3.23). Among 948 treated IS patients, DIH remained a significant risk for worse outcomes (OR, CI: 2.54, 1.89-3.43).

Conclusion: Delirium was twice as common in IS patients and was a negative prognostic indicator of short and long-term outcomes among non-treated and treated IS patients. Active screening and management of DIH is critically important to improve stroke outcomes.

Exercise Intolerance in Older Adults With Heart Failure With Preserved Ejection Fraction: JACC State-of-the-Art Review

Exercise intolerance (EI) is the primary manifestation of chronic heart failure with preserved ejection fraction (HFpEF), the most common form of heart failure among older individuals. The recent recognition that HFpEF is likely a systemic, multiorgan disorder that shares characteristics with other common, difficult-to-treat, aging-related disorders suggests that novel insights may be gained from combining knowledge and concepts from aging and cardiovascular disease disciplines. This state-of-the-art review is based on the outcomes of a National Institute of Aging-sponsored working group meeting on aging and EI in HFpEF. We discuss aging-related and extracardiac contributors to EI in HFpEF and provide the rationale for a transdisciplinary, "gero-centric" approach to advance our understanding of EI in HFpEF and identify promising new therapeutic targets. We also provide a framework for prioritizing future research, including developing a uniform, comprehensive approach to phenotypic characterization of HFpEF, elucidating key geroscience targets for treatment, and conducting proof-of-concept trials to modify these targets.

Abstract P400: Treatment With The AMPK Agonist AICAR Alleviates Age-associated Cardiac Defects In The Mouse By Distinct Sex-specific Mechanisms

Heart failure is a major cause of mortality in the elderly. Features of cardiac aging include diastolic dysfunction and interstitial fibrosis with sex-specific differences.

We treated old male and female mice (21 months-old) 3 times a week for 3 months with the AMPK agonist 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR, 0.166 mg/g BW). We previously reported that AICAR normalizes the aged fibroblast phenotype.

In a longitudinal study, we found that AICAR attenuates the age-associated increase in left atrial volume, an indirect indicator of diastolic dysfunction, in female AICAR-treated mice (-29% ±5%) but not in males (-7% ±6%). Cardiac fibroblasts from AICAR-treated mice expressed decreased pro-collagen levels by 42% (mean fluorescence intensity, P=0.0003 for females, and P=0.05 for males). Cardiac fibroblasts cultured on decellularized cardiac matrices also had a reduced expression of pro-collagen when treated with AICAR (0.5mM, 7 days). Myocardial hydroxyproline level (an indicator of total collagen content) was reduced in female hearts (from 0.83 ± 0.07 in controls to 0.48 ± 0.05 in AICAR-treated, P=0.006). Female cells also exhibited a reduced expression of periostin after treatment (by 65%, P=0.02). By contrast, age-matched control males had a lower cardiac level of hydroxyproline (-65%, P=0.0002) and periostin (-45%, P=0.0004) than females, and were not affected by the treatment.

Accumulation of defective mitochondria is a hallmark of aging. Since AICAR can favor mitophagy, we isolated mitochondrial fractions from the hearts of old mice undergoing treatment. We found that AICAR decreased Parkin level in the small mitochondria fraction (0.75±0.09, P=0.028) in males, but no significant change was found between the groups of females. The reduction of Parkin may suggest improved clearance of defective mitochondria.For all experiments, we used 4-10 animals per group. One-way Anova or student’s T-test evaluated statistical significance.

In conclusion, age-associated cardiac remodeling leads to distinct patterns between male and female mice. AICAR treatment can have sex-specific effects: it reduces fibrosis in females but may promote mitophagy in males, translating into an improvement of heart function via distinct mechanisms.

NLRP3 inflammasome is a key driver of obesity-induced atrial arrhythmias

AIMS

Obesity, an established risk factor of atrial fibrillation (AF), is frequently associated with enhanced inflammatory response. However, whether inflammatory signaling is causally linked to AF pathogenesis in obesity remains elusive. We recently demonstrated that the constitutive activation of the 'NACHT, LRR, and PYD Domains-containing Protein 3' (NLRP3) inflammasome promotes AF susceptibility. In this study, we hypothesized that the NLRP3 inflammasome is a key driver of obesity-induced AF.

METHODS AND RESULTS

Western blotting was performed to determine the level of NLRP3 inflammasome activation in atrial tissues of obese patients, sheep, and diet-induced obese (DIO) mice. The increased body weight in patients, sheep, and mice was associated with enhanced NLRP3-inflammasome activation. To determine whether NLRP3 contributes to the obesity-induced atrial arrhythmogenesis, wild-type (WT) and NLRP3 homozygous knockout (NLRP3-/-) mice were subjected to high-fat-diet (HFD) or normal chow (NC) for 10 weeks. Relative to NC-fed WT mice, HFD-fed WT mice were more susceptible to pacing-induced AF with longer AF duration. In contrast, HFD-fed NLRP3-/- mice were resistant to pacing-induced AF. Optical mapping in DIO mice revealed an arrhythmogenic substrate characterized by abbreviated refractoriness and action potential duration (APD), two key determinants of reentry-promoting electrical remodeling. Upregulation of ultra-rapid delayed-rectifier K+-channel (Kv1.5) contributed to the shortening of atrial refractoriness. Increased profibrotic signaling and fibrosis along with abnormal Ca2+ release from sarcoplasmic reticulum (SR) accompanied atrial arrhythmogenesis in DIO mice. Conversely, genetic ablation of Nlrp3 (NLRP3-/-) in HFD-fed mice prevented the increases in Kv1.5 and the evolution of electrical remodeling, the upregulation of profibrotic genes, and abnormal SR Ca2+ release in DIO mice.

CONCLUSION

These results demonstrate that the atrial NLRP3 inflammasome is a key driver of obesity-induced atrial arrhythmogenesis and establishes a mechanistic link between obesity-induced AF and NLRP3-inflammasome activation.

Decade-Long Nationwide Trends and Disparities in Use of Comfort Care Interventions for Patients With Ischemic Stroke

Background Stroke remains one of the leading causes of disability and death in the United States. We characterized 10-year nationwide trends in use of comfort care interventions (CCIs) among patients with ischemic stroke, particularly pertaining to acute thrombolytic therapy with intravenous tissue-type plasminogen activator and endovascular thrombectomy, and describe in-hospital outcomes and costs. Methods and Results We analyzed the National Inpatient Sample from 2006 to 2015 and identified adult patients with ischemic stroke with or without thrombolytic therapy and CCIs using validated International Classification of Diseases, Ninth Revision (ICD-9) codes. We report adjusted odds ratios (ORs) and 95% CI of CCI usage across five 2-year periods. Of 4 249 201 ischemic stroke encounters, 3.8% had CCI use. CCI use increased over time (adjusted OR, 4.80; 95% CI, 4.15-5.55) regardless of acute treatment type. Advanced age, female sex, White race, non-Medicare insurance, higher income, disease severity, comorbidity burden, and discharge from non-northeastern teaching hospitals were independently associated with receiving CCIs. In the fully adjusted model, thrombolytic therapy and endovascular thrombectomy, respectively, conferred a 6% and 10% greater likelihood of receiving CCIs. Among CCI users, there was a significant decline in in-hospital mortality compared with all other dispositions over time (adjusted OR, 0.46; 95% CI, 0.38-0.56). Despite longer length of stay, CCI hospitalizations incurred 16% lower adjusted costs. Conclusions CCI use among patients with ischemic stroke has increased regardless of acute treatment type. Nonetheless, considerable disparities persist. Closing the disparities gap and optimizing access, outcomes, and costs for CCIs among patients with stroke are important avenues for further research.

Implementing Health Care Quality Measures in Electronic Health Records: A Conceptual Model

BACKGROUND/OBJECTIVES

There is significant literature on the development and validation of quality measures, but comparably less on their implementation into learning health systems. Electronic Health Records (EHRs) have made vast amounts of data available for quality improvement purposes. In this paper we describe a conceptual model for EHR implementation of quality measures.

DESIGN

The model involves five steps: (1) select a measure; (2) define measure criteria; (3) validate criteria and measurement process; (4) improve recording of measure-related activity; and (5) engage quality improvement processes. The model was used to develop and implement a quality measure in the Home-Based Medical Care (HBMC) setting.

SETTING

Harris Health House Call Program (HHHC) provides primary medical and palliative care for homebound patients in Houston.

PARTICIPANTS

Four-hundred twenty-four primary care patients followed in the HHHC.

MEASUREMENT

Completion rate of the 9-item Patient Health Questionnaire (PHQ-9) within the Electronic Health Record of newly enrolled HHHC patients.

RESULTS

Use of the conceptual model to guide implementation of a quality measure of depression screening in a HMBC practice was successful. Additional components of early leadership and clinician buy-in were required, as well as strong relationships with IT to ease implementation and limit disruptions in clinicians' work-flow.

CONCLUSION

This conceptual model was feasible for guiding implementation of a quality measure for depression care of HBMC patients, and it can guide broader implementation of EHR-based quality measures in the future.

Aortic acceleration as a noninvasive index of left ventricular contractility in the mouse

The maximum value of the first derivative of the invasively measured left ventricular (LV) pressure (+ dP/dtmax or P') is often used to quantify LV contractility, which in mice is limited to a single terminal study. Thus, determination of P' in mouse longitudinal/serial studies requires a group of mice at each desired time point resulting in "pseudo" serial measurements. Alternatively, a noninvasive surrogate for P' will allow for repeated measurements on the same group of mice, thereby minimizing physiological variability and requiring fewer animals. In this study we evaluated aortic acceleration and other parameters of aortic flow velocity as noninvasive indices of LV contractility in mice. We simultaneously measured LV pressure invasively with an intravascular pressure catheter and aortic flow velocity noninvasively with a pulsed Doppler probe in mice, at baseline and after the administration of the positive inotrope, dobutamine. Regression analysis of P' versus peak aortic velocity (vp), peak velocity squared/rise time (vp2/T), peak (+ dvp/dt or v'p) and mean (+ dvm/dt or v'm) aortic acceleration showed a high degree of association (P' versus: vp, r2 = 0.77; vp2/T, r2 = 0.86; v'p, r2 = 0.80; and v'm, r2 = 0.89). The results suggest that mean or peak aortic acceleration or the other parameters may be used as a noninvasive index of LV contractility.

Plasma Dehydroepiandrosterone Sulfate and Cardiovascular Disease Risk in Older Men and Women

CONTEXT

Lower dehydroepiandrosterone-sulfate (DHEA-S) levels have been inconsistently associated with coronary heart disease (CHD) and mortality. Data are limited for heart failure (HF) and association between DHEA-S change and events.

OBJECTIVE

Assess associations between low DHEA-S/DHEA-S change and incident HF hospitalization, CHD, and mortality in older adults.

DESIGN

DHEA-S was measured in stored plasma from visits 4 (1996-1998) and 5 (2011-2013) of the Atherosclerosis Risk in Communities study. Follow-up for incident events: 18 years for DHEA-S level; 5.5 years for DHEA-S change.

SETTING

General community.

PARTICIPANTS

Individuals without prevalent cardiovascular disease (n = 8143, mean age 63 years).

MAIN OUTCOME MEASURE

Associations between DHEA-S and incident HF hospitalization, CHD, or mortality; associations between 15-year change in DHEA-S (n = 3706) and cardiovascular events.

RESULTS

DHEA-S below the 15th sex-specific percentile of the study population (men: 55.4 µg/dL; women: 27.4 µg/dL) was associated with increased HF hospitalization (men: hazard ratio [HR] 1.30, 95% confidence interval [CI], 1.07-1.58; women: HR 1.42, 95% CI, 1.13-1.79); DHEA-S below the 25th sex-specific percentile (men: 70.0 µg/dL; women: 37.1 µg/dL) was associated with increased death (men: HR 1.12, 95% CI, 1.01-1.25; women: HR 1.19, 95% CI, 1.03-1.37). In men, but not women, greater percentage decrease in DHEA-S was associated with increased HF hospitalization (HR 1.94, 95% CI, 1.11-3.39). Low DHEA-S and change in DHEA-S were not associated with incident CHD.

CONCLUSIONS

Low DHEA-S is associated with increased risk for HF and mortality but not CHD. Further investigation is warranted to evaluate mechanisms underlying these associations.

Treatment with a DC-SIGN ligand reduces macrophage polarization and diastolic dysfunction in the aging female but not male mouse hearts

Cardiac diastolic dysfunction in aging arises from increased ventricular stiffness caused by inflammation and interstitial fibrosis. The diastolic dysfunction contributes to heart failure with preserved ejection fraction (HFpEF), which in the aging population is more common in women. This report examines its progression over 12 weeks in aging C57BL/6J mice and correlates its development with changes in macrophage polarization and collagen deposition.

Aged C57BL/6J mice were injected with dendritic cell–specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) ligand 1 (DCSL1, an anti-inflammatory agent) or saline for 12 weeks. Echo and Doppler measurements were performed before and after 4 and 12 weeks of treatment. DCSL1 prevented the worsening of diastolic dysfunction over time in females but not in males. Cardiac single cell suspensions analyzed by flow cytometry revealed changes in the inflammatory infiltrate: (1) in males, there was an increased total number of leukocytes with an increased pro-inflammatory profile compared with females and they did not respond to DCSL1; (2) by contrast, DCSL1 treatment resulted in a shift in macrophage polarization to an anti-inflammatory phenotype in females. Notably, DCSL1 preferentially targeted tumor necrosis factor-α (TNFα⁺) pro-inflammatory macrophages. The reduction in pro-inflammatory macrophage polarization was accompanied by a decrease in collagen content in the heart.

Age-associated diastolic dysfunction in mice is more severe in females and is associated with unique changes in macrophage polarization in cardiac tissue. Treatment with DCSL1 mitigates the changes in inflammation, cardiac function, and fibrosis. The characteristics of diastolic dysfunction in aging female mice mimic similar changes in aging women.

CORRECTING GLUTATHIONE DEFICIENCY AND MITOCHONDRIAL DYSFUNCTION IN OLDER HUMANS: A RANDOMIZED CLINICAL TRIAL

Aging is associated with impaired mitochondrial fatty-acid oxidation (MFO) due to unknown mechanisms, and interventions are lacking. We hypothesized that impaired MFO in aging occurs due to Glutathione-deficiency and tested this in a randomized, placebo-controlled double-blind clinical-trial in 24 older-humans (71.1y) and 12 young-controls (25.5y) using calorimetry, muscle-biopsy and tracer-protocols. Older-humans received either GlyNAC (Glycine 1.33mmol/kg/d and N-acetylcysteine 0.83mmol/kg/d as Glutathione precursors) or isonitrogenous-placebo for 16-weeks; young-controls received GlyNAC for 2-weeks. Compared to young-controls, older humans had significantly lower Glutathione, impaired MFO, lower gait-speed and physical-function, and higher oxidative-stress, inflammation and insulin-resistance. GlyNAC supplementation in older-humans significantly improved and restored MFO; increased gait-speed (19%,) and physical-function; and decreased oxidative-stress (TBARS 80%), inflammation (IL-6 83%; TNF-alpha 58%), and insulin-resistance (HOMA-IR 68%), but young-controls were unaffected. These data provide proof-of-concept that GlyNAC supplementation could improve the health of older-humans by correcting Glutathione-deficiency and mitochondrial-defects to improve gait-speed, oxidative-stress, inflammation and insulin-resistance.

GLUTATHIONE DEFICIENCY AND OXIDATIVE STRESS IN AGING: METABOLIC MECHANISM AND TARGETED INTERVENTION

The free-radical theory of aging suggests that age-related functional decline is mediated by increases in free-radical induced oxidative-stress. Cells normally depend on antioxidants for protection against oxidative-stress. Glutathione is the most abundant endogenous intracellular antioxidant protein composed of 3 amino-acids, cysteine, glycine and glutamic-acid, and is known to be deficient in older-humans. We investigated Glutathione kinetics in older humans using a stable-isotope tracer-based approach, and found that compared to younger humans, older-humans had severe Glutathione deficiency as a result of decreased synthesis caused by limited availability of glycine and cysteine, and associated with elevated oxidative-stress. Orally supplementing glycine and cysteine (provided as N-acetylcysteine) at doses of 1.33mmol/kg/d and 0.81mmol/kg/d respectively for 2-weeks corrected their intracellular deficiency, normalized Glutathione synthesis rates and lowered oxidative-stress to levels in younger controls. These results suggest that short-term supplementation of GlyNAC at these doses can successfully correct intracellular Glutathione deficiency in older-humans.

CORRECTING GLUTATHIONE DEFICIENCY IN AGING: IMPACT ON MITOCHONDRIA, STRENGTH, INFLAMMATION AND METABOLIC DEFECTS

Aging is associated with deficiency of Glutathione, the most abundant, intracellular, antioxidant protein, but underlying mechanisms are unknown and interventions limited. This symposium is primarily focused on the results of placebo-controlled, double-blind randomized clinical-trial (RCT) on the impact of correcting Glutathione deficiency in older humans on mitochondrial impairment, oxidative stress, strength, inflammation, and insulin resistance. Dr. Jahoor’s presentation will serve as an introduction by discussing mechanisms underlying Glutathione deficiency and validation of a novel nutritional intervention based on supplementing glycine and N-acetylcysteine (GlyNAC) to correct Glutathione deficiency in older-humans. Dr. Sekhar will present the results of a pilot 16-week pilot randomized, placebo-controlled, double-blind clinical trial in older humans investigating the effect of supplementing GlyNAC (vs. placebo) to improve Glutathione levels and oxidative-stress in 24 older-humans and 12 young-humans on impaired mitochondrial fuel-oxidation (MFO) and other defects. The trial met its primary objective that that GlyNAC supplementation (and not placebo) significantly improved Glutathione deficiency and corrected impaired MFO (and defects in its molecular regulation), and also significantly improved gait-speed (increased 19% increase to match young-humans), muscle-strength, exercise-capacity, and lowered oxidative-stress (80%) inflammation (IL-6 83%, TNF-alpha 58%), and insulin-resistance (68%). Dr. Taffet will discuss age-induced diastolic heart failure, and the effect of supplementing GlyNAC (vs. NAC alone) in aged 24-month old mice with diastolic heart-failure, impaired myocardial MFO and cardiac-inflammation. Collectively this symposium on Glutathione and Aging will highlight the discovery that supplementing GlyNAC to correct Glutathione deficiency in older-humans has significant health benefits, and could be a novel nutritional-intervention in aging.

GLUTATHIONE, INFLAMMATION, MITOCHONDRIAL FAT OXIDATION AND DIASTOLIC HEART FUNCTION IN OLD MICE

Impaired diastolic function is a risk factor for diastolic heart failure, may limit exercise performance, and is common in aging in both people and animals. This diastolic dysfunction seems to be associated with cardiac inflammation, fibrosis and impaired mitochondrial fatty acid metabolism. Old (24-28 m) mice fed a GlyNAC supplemented diet for 8 weeks were compared to those on control diet, and had dramatic improvement in all these parameters. For example, ATP generation from fatty acids with five-fold higher in the GlyNAC supplemented mice. In vitro studies compared NAC with GlyNAC and demonstrated the benefits only with supplementing both amino acids as compared to NAC alone. These data suggest that GlyNAC may have a role in improving cardiac function thus improving exercise tolerance and quality of life for older people.

Improved Cardiovascular Function in Old Mice After N-Acetyl Cysteine and Glycine Supplemented Diet: Inflammation and Mitochondrial Factors

Metabolic, inflammatory, and functional changes occur in cardiovascular aging which may stem from oxidative stress and be remediable with antioxidants. Glutathione, an intracellular antioxidant, declines with aging, and supplementation with glutathione precursors, N-acetyl cysteine (NAC) and glycine (Gly), increases tissue glutathione. Thirty-month old mice were fed diets supplemented with NAC or NAC+Gly and, after 7 weeks, cardiac function and molecular studies were performed. The NAC+Gly supplementation improved diastolic function, increasing peak early filling velocity, and reducing relaxation time, left atrial volume, and left ventricle end diastolic pressure. By contrast, cardiac function did not improve with NAC alone. Both diet supplementations decreased cardiac levels of inflammatory mediators; only NAC+Gly reduced leukocyte infiltration. Several mitochondrial genes reduced with aging were upregulated in hearts by NAC+Gly diet supplementation. These Krebs cycle and oxidative phosphorylation enzymes, suggesting improved mitochondrial function, and permeabilized cardiac fibers from NAC+Gly-fed mice produced ATP from carbohydrate and fatty acid sources, whereas fibers from control old mice were less able to utilize fatty acids. Our data indicate that NAC+Gly supplementation can improve diastolic function in the old mouse and may have potential to prevent important morbidities for older people.

MAP4K4 Inhibition Promotes Survival of Human Stem Cell-Derived Cardiomyocytes and Reduces Infarct Size In Vivo

Heart disease is a paramount cause of global death and disability. Although cardiomyocyte death plays a causal role and its suppression would be logical, no clinical counter-measures target the responsible intracellular pathways. Therapeutic progress has been hampered by lack of preclinical human validation. Mitogen-activated protein kinase kinase kinase kinase-4 (MAP4K4) is activated in failing human hearts and relevant rodent models. Using human induced-pluripotent-stem-cell-derived cardiomyocytes (hiPSC-CMs) and MAP4K4 gene silencing, we demonstrate that death induced by oxidative stress requires MAP4K4. Consequently, we devised a small-molecule inhibitor, DMX-5804, that rescues cell survival, mitochondrial function, and calcium cycling in hiPSC-CMs. As proof of principle that drug discovery in hiPSC-CMs may predict efficacy in vivo, DMX-5804 reduces ischemia-reperfusion injury in mice by more than 50%. We implicate MAP4K4 as a well-posed target toward suppressing human cardiac cell death and highlight the utility of hiPSC-CMs in drug discovery to enhance cardiomyocyte survival.

Postnatal undernutrition alters adult female mouse cardiac structure and function leading to limited exercise capacity

KEY POINTS

Impaired growth during fetal life can reprogramme heart development and increase the risk for long-term cardiovascular dysfunction. It is uncertain if the developmental window during which the heart is vulnerable to reprogramming as a result of inadequate nutrition extends into the postnatal period. We found that adult female mice that had been undernourished only from birth to 3 weeks of age had disproportionately smaller hearts compared to males, with thinner ventricle walls and more mononucleated cardiomyocytes. In females, but not males, cardiac diastolic function, and heart rate responsiveness to adrenergic stimulation were limited and maximal exercise capacity was compromised. These data suggest that the developmental window during which the heart is vulnerable to reprogramming by inadequacies in nutrient intake may extend into postnatal life and such individuals could be at increased risk for a cardiac event as a result of strenuous exercise.

ABSTRACT

Adults who experienced undernutrition during critical windows of development are at increased risk for cardiovascular disease. The contribution of cardiac function to this increased disease risk is uncertain. We evaluated the effect of a short episode of postnatal undernutrition on cardiovascular function in mice at the whole animal, organ, and cellular levels. Pups born to control mouse dams were suckled from birth to postnatal day (PN) 21 on dams fed either a control (20% protein) or a low protein (8% protein) isocaloric diet. After PN21 offspring were fed the same control diet until adulthood. At PN70 V ̇ O 2 , max was measured by treadmill test. At PN80 cardiac function was evaluated by echocardiography and Doppler analysis at rest and following β-adrenergic stimulation. Isolated cardiomyocyte nucleation and Ca²⁺ transients (with and without β-adrenergic stimulation) were measured at PN90. Female mice that were undernourished and then refed (PUN), unlike male mice, had disproportionately smaller hearts and their exercise capacity, cardiac diastolic function, and heart rate responsiveness to adrenergic stimulation were limited. A reduced left ventricular end diastolic volume, impaired early filling, and decreased stored energy at the beginning of diastole contributed to these impairments. Female PUN mice had more mononucleated cardiomyocytes; under resting conditions binucleated cells had a functional profile suggestive of increased basal adrenergic activation. Thus, a brief episode of early postnatal undernutrition in the mouse can produce persistent changes to cardiac structure and function that limit exercise/functional capacity and thereby increase the risk for the development of a wide variety of cardiovascular morbidities.

Transient activation of AMPK preceding left ventricular pressure overload reduces adverse remodeling and preserves left ventricular function

Coordinated changes in signaling pathways and gene expression in hearts subjected to prolonged stress maintain cardiac function. Loss of steroid receptor coactivator-2 (SRC-2) results in a reversal to the fetal gene program and disrupts the response to pressure overload, accompanied by prominent effects on metabolism and growth signaling, including increased AMPK activation. We proposed that early metabolic stress driven by AMPK activation induces contractile dysfunction in mice lacking SRC-2. We used 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) to activate AMPK transiently before transverse aortic constriction (TAC) in wild-type and cardiomyocyte-specific SRC-2 knockout (CKO) animals. In contrast to AMPK activities during stress, in unstressed hearts, AICAR induced a mild activation of Akt signaling, and, in SRC-2-CKO mice, partially relieved an NAD⁺ deficiency and increased antioxidant signaling. These molecular changes translated to a mild hypertrophic response to TAC with decreased maladaptive remodeling, including markedly decreased fibrosis. Additionally, preactivation of AMPK in SRC-2-CKO mice was accompanied by a dramatic improvement in cardiac function compared with saline-treated SRC-2-CKO mice. Our results show that altered molecular signaling before stress onset has extended effects on sustained cardiac stress responses, and prestress modulation of transient growth and metabolism pathways may control those effects.-Nam, D. H., Kim, E., Benham, A., Park, H.-K., Soibam, B., Taffet, G. E., Kaelber, J. T., Suh, J. H., Taegtmeyer, H., Entman, M. L., Reineke, E. L. Transient activation of AMPK preceding left ventricular pressure overload reduces adverse remodeling and preserves left ventricular function.

Prevalence of Cognitive Impairment Among Elderly Patients Upon Hospital Admission Using Mini-Cog™ Assessments Performed by Advanced Pharmacy Practice Experience Students

BACKGROUND

Older adults with cognitive impairment may have difficulty understanding and complying with medical or medication instructions provided during hospitalization which may adversely impact patient outcomes.

OBJECTIVE

To evaluate the prevalence of cognitive impairment among patients aged 65 years and older within 24 hours of hospital admission using Mini-Cog™ assessments performed by advanced pharmacy practice experience (APPE) students.

METHODS

Students on APPE rotations were trained to perform Mini-Cog™ assessments during routine medication education sessions from February 2017 to April 2017. The primary end point was the prevalence of cognitive impairment indicated by a Mini-Cog™ score of ≤3. Secondary end points were the average number of observed Mini-Cog™ practice assessments required for APPE students to meet competency requirements, caregiver identification, and 30-day hospital readmissions.

RESULTS

Twelve APPE students completed the training program after an average of 4.4 (standard deviation [SD] = 1.0) graded Mini-Cog™ assessments. Of the 1159 admissions screened, 273 were included in the analysis. The prevalence of cognitive impairment was 55% (n = 149, 95% confidence interval [CI]: 48%-61%). A caregiver was identified for 41% (n = 113, 95% CI: 35%-47%) of patients, and 79 patients had a caregiver present at bedside during the visit. Hospital readmission within 30 days of discharge was 15% (n = 41, 95% CI: 11%-20%).

CONCLUSION

Cognitive impairment could substantially impair a patient's ability to comprehend education provided during hospitalization. Pharmacy students can feasibly perform Mini-Cog™ assessments to evaluate cognitive function, thereby allowing them to tailor education content and involve caregivers when necessary.

Short-Term Global Cardiovascular Disease Risk Prediction in Older Adults

BACKGROUND

Current prevention guidelines recommend using the Pooled Cohort Equation (PCE) for 10-year atherosclerotic cardiovascular disease (CVD) risk assessment. However, the PCE has serious limitations in older adults: it excludes heart failure (HF) hospitalization, estimates 10-year risk, which may not be the most relevant time frame, and is not indicated for individuals age >79 years.

OBJECTIVES

This study sought to determine whether adding biomarkers to PCE variables improves global CVD (coronary heart disease, stroke, and HF) risk prediction in older adults over a shorter time period.

METHODS

Atherosclerosis Risk in Communities study participants without prevalent CVD including HF (n = 4,760; age 75.4 ± 5.1 years) were followed for incident global CVD events. Adding N-terminal pro-B-type natriuretic peptide, high-sensitivity cardiac troponin T, and high-sensitivity C-reactive protein to the PCE and a "lab model" with the biomarkers, age, race, and gender were assessed for prediction improvement. Area under the receiver operating characteristic curve (AUC) and net reclassification index (NRI) were calculated.

RESULTS

Over median follow-up of ∼4 years, incident HF was the leading CVD event (n = 193 vs. 118 coronary heart disease and 81 stroke events). Compared to the PCE, each biomarker improved risk prediction. The largest improvement in risk prediction metrics was with the addition of all 3 biomarkers (ΔAUC 0.103; continuous NRI 0.484). The lab model also performed better than the PCE model (ΔAUC 0.091, continuous NRI 0.355).

CONCLUSIONS

Adding biomarkers to the PCE or a simpler "lab model" improves short-term global CVD risk prediction and may be useful to inform short-term preventive strategies in older adults.

Steroid receptor coactivator-2 (SRC-2) coordinates cardiomyocyte paracrine signaling to promote pressure overload-induced angiogenesis

Pressure overload-induced cardiac stress induces left ventricular hypertrophy driven by increased cardiomyocyte mass. The increased energetic demand and cardiomyocyte size during hypertrophy necessitate increased fuel and oxygen delivery and stimulate angiogenesis in the left ventricular wall. We have previously shown that the transcriptional regulator steroid receptor coactivator-2 (SRC-2) controls activation of several key cardiac transcription factors and that SRC-2 loss results in extensive cardiac transcriptional remodeling. Pressure overload in mice lacking SRC-2 induces an abrogated hypertrophic response and decreases sustained cardiac function, but the cardiomyocyte-specific effects of SRC-2 in these changes are unknown. Here, we report that cardiomyocyte-specific loss of SRC-2 (SRC-2 CKO) results in a blunted hypertrophy accompanied by a rapid, progressive decrease in cardiac function. We found that SRC-2 CKO mice exhibit markedly decreased left ventricular vasculature in response to transverse aortic constriction, corresponding to decreased expression of the angiogenic factor VEGF. Of note, SRC-2 knockdown in cardiomyocytes decreased VEGF expression and secretion to levels sufficient to blunt in vitro tube formation and proliferation of endothelial cells. During pressure overload, both hypertrophic and hypoxic signals can stimulate angiogenesis, both of which stimulated SRC-2 expression in vitro Furthermore, SRC-2 coactivated the transcription factors GATA-binding protein 4 (GATA-4) and hypoxia-inducible factor (HIF)-1α and -2α in response to angiotensin II and hypoxia, respectively, which drive VEGF expression. These results suggest that SRC-2 coordinates cardiomyocyte secretion of VEGF downstream of the two major angiogenic stimuli occurring during pressure overload bridging both hypertrophic and hypoxia-stimulated paracrine signaling.

Cardiac Resynchronization Therapy in Older Adults with Heart Failure

Heart failure is a disease of poor prognosis marked by frequent hospitalizations, premature death, and impaired quality of life. Despite advances in medical therapy for patients with heart failure and reduced ejection fraction, mortality and hospitalizations with advanced disease are still increased and the quality of life continues to be poor in this population. The advent of cardiac resynchronization therapy has led to a significant improvement in both survival and symptom management in patients with heart failure and reduced ejection fraction. Its beneficial effects in the elderly population, however, are not well-defined.

Dissecting the role of myeloid and mesenchymal fibroblasts in age-dependent cardiac fibrosis

Aging is associated with increased cardiac interstitial fibrosis and diastolic dysfunction. Our previous study has shown that mesenchymal fibroblasts in the C57BL/6J (B6J) aging mouse heart acquire an inflammatory phenotype and produce higher levels of chemokines. Monocyte chemoattractant protein-1 (MCP-1) secreted by these aged fibroblasts promotes leukocyte uptake into the heart. Some of the monocytes that migrate into the heart polarize into M2a macrophages/myeloid fibroblasts. The number of activated mesenchymal fibroblasts also increases with age, and consequently, both sources of fibroblasts contribute to fibrosis. Here, we further investigate mechanisms by which inflammation influences activation of myeloid and mesenchymal fibroblasts and their collagen synthesis. We examined cardiac fibrosis and heart function in three aged mouse strains; we compared C57BL/6J (B6J) with two other strains that have reduced inflammation via different mechanisms. Aged C57BL/6N (B6N) hearts are protected from oxidative stress and fibroblasts derived from them do not develop an inflammatory phenotype. Likewise, these mice have preserved diastolic function. Aged MCP-1 null mice on the B6J background (MCP-1KO) are protected from elevated leukocyte infiltration; they develop moderate but reduced fibrosis and diastolic dysfunction. Based on these studies, we further delineated the role of resident versus monocyte-derived M2a macrophages in myeloid-dependent fibrosis and found that the number of monocyte-derived M2a (but not resident) macrophages correlates with age-related fibrosis and diastolic dysfunction. In conclusion, we have found that ROS and inflammatory mediators are necessary for activation of fibroblasts of both developmental origins, and prevention of either led to better functional outcomes.

Murine Echocardiography of Left Atrium, Aorta, and Pulmonary Artery

The present methodology teaches the investigator how to measure and use the LAV as a surrogate of chronic elevations in Left Ventricular diastolic pressure through echocardiography, as well as to obtain measurements of the Aorta and PA diameter in mice. Mice older than 10 d of age can be analyzed using the present technique. The technique is composed of 3 main steps: set-up, image acquisition, and image analysis. The set-up step consists of getting the mouse anesthetized with 1% isoflurane, shaving it, and taping it in a supine position to a heated EKG board where the image acquisition will take place. The image acquisition step consists of learning to identify the cardiac structures and obtaining all the required images with its correspondent probe and axis in order to be able to calculate volumes and diameters. The image analysis step consists of measuring the previously acquired images with the aid of computer software. Advantages of the proposed technique include a fast (15 min) procedure that would allow the researcher to evaluate interventions in a non-invasive, non-terminal approach and therefore follow the same mouse over time; each mouse can be used as its own control. This fact plus having the same operator perform all the acquisition and analysis for the entire experiment minimizes the limitation of operator-dependency. The present methodology is useful for mouse researchers in cardiovascular and pulmonary medicine.

Unrecognized Cognitive Impairment and Its Effect on Heart Failure Readmissions of Elderly Adults

OBJECTIVES

To determine whether 30-day readmissions were associated with presence of cognitive impairment more in elderly adults with heart failure (HF) than in those with other diagnoses and whether medical teams recognized cognitive impairment.

DESIGN

One-year prospective cohort quality improvement program of cognitive screening and retrospective chart review of documentation and outcomes.

SETTING

Academic tertiary care hospital medical unit with a cardiovascular focus and an enhanced discharge program of individualized patient education.

PARTICIPANTS

Individuals aged 70 and older screened before home discharge (241 admission encounters; 121 with HF as a primary diagnosis, 120 without). The HF cohort included individuals with preserved and reduced ejection fraction. Individuals who had undergone transplantation, ventricular assist device implantation, or hemodialysis or who had a primary oncology diagnosis or hospice referral were excluded.

MEASUREMENTS

Mini-Cog administered 48 hours or less before discharge, 30-day all-cause readmission rates, documentation of dementia or cognitive impairment, and caregiver education.

RESULTS

Mini-Cog scores were less than 4 (indicating cognitive impairment) in 157 encounters (82 (67.7%) with HF, 75 (62.5%) without). Mini-Cog scores were similar in rate and distribution between groups. Individuals with HF and cognitive impairment had a significantly higher 30-day readmission rate than did the other groups (26.8% vs 13.2%; P = .01; HF, no cognitive impairment, 12.8%; no HF, no cognitive impairment, 13.3%; cognitive impairment, no HF, 13.3%). In individuals with HF and cognitive impairment, those with documented caregiver education had lower readmission rates than those without (14.3% vs 36.2%; P = .03). Fewer than 9% had documentation of cognitive impairment in the medical record.

CONCLUSION

Cognitive impairment, which is frequently undocumented, may indicate greater risk of readmission for individuals with HF than those without. Screening for cognitive impairment, adapting discharge for it, and involving family and caregivers in discharge education may help reduce readmissions.

Abstract 129: Transient Activation of AMPK Prior to Cardiac Pressure Overload Alleviates Fibrotic Accumulation and Functional Decline

The multiple adaptive pathways activated during cardiac stress must communicate with each other for an efficient response; however, little is known about the molecular mechanisms underlying this coordination. During left ventricular pressure overload induced by transverse aortic constriction (TAC), an increase in metabolic flux to meet the ATP demand is the first molecular change observed in the heart. Following initial metabolic changes, there is genetic remodeling of the metabolic machinery and activation of other acute and long-term adaptive pathways to control hypertrophy, fibrosis, and contraction. In order to better understand how the early metabolic changes affect the activation and magnitude of the downstream pathways, we treated mice with the AMPK activator AICAR for 6 days prior to TAC and then monitored effects on the cardiac stress response for 4 weeks. This treatment was performed in both WT mice and in mice lacking cardiomyocyte expression of steroid receptor coactivator-2 (SRC-2 CKO), a model we have previously shown to be genetically similar to a stressed mouse and whose function declines rapidly in response to TAC. Interestingly, we found that this small transient treatment with AICAR is sufficient to blunt hypertrophy (20% reduction) and fibrotic accumulation (56% reduction) and prevent left ventricular dilation and pleural edema. Furthermore, AICAR treatment in the SRC-2 CKO animals was able to rescue the functional decline observed post-TAC. We are currently investigating the molecular pathways underlying these changes. Our results strongly suggest that there are very early events during cardiac stress that are key determinants in the ability of the heart to adapt and maintain function under stress, even in late stages post-stress. Disruption of these determinants can lead to rapid failure, whereas their promotion could hold a key for therapeutic intervention.

TNF/Ang-II synergy is obligate for fibroinflammatory pathology, but not for changes in cardiorenal function

Angiotensin‐II (Ang‐II) infusion is associated with the development of interstitial fibrosis in both heart and kidney as a result of chemokine‐dependent uptake of monocytes and subsequent development of myeloid fibroblasts. This study emphasizes on the synergistic role of tumor necrosis factor (TNF) on the time course of Ang‐II‐induced fibrosis and inflammation in heart and kidney. In wild‐type (WT) hearts, Ang‐II‐induced fibrosis peaked within 1 week of infusion and remained stable over a 6‐week period, while the myeloid fibroblasts disappeared; TNF receptor‐1‐knockout (TNFR1‐KO) hearts did not develop a myeloid response or cardiac fibrosis during this time. WT hearts developed more accelerated cardiac hypertrophy and remodeling than TNFR1‐KO. In the kidney, 1‐week Ang‐II infusion did not evoke a fibrotic response; however, after 6 weeks, WT kidneys displayed modest but significant tubulointerstitial collagen deposition associated with the appearance of myeloid cells and profibrotic gene activation. Renal fibrosis was not seen in Ang‐II‐infused TNFR1‐KO. By contrast, while hypertension increased and cardiac function decreased more slowly in TNFR1‐KO than WT, they were equivalently abnormal at 6 weeks. Similarly, serum markers for renal dysfunction were not different after 6 weeks. In conclusion, Ang‐II infusion initiated fibroinflammatory responses with different time courses in heart and kidney, both requiring TNFR1 signaling, and both associated with monocyte‐derived myeloid fibroblasts. TNFR1 deletion obviated the fibroinflammatory effects of Ang‐II, but did not alter changes in blood pressure and cardiorenal function after 6 weeks. Thus, the synergy of TNF with Ang‐II targets the fibroinflammatory component of Ang‐II signaling.

Plasma Levels of Endothelial Microparticles Bearing Monomeric C-reactive Protein are Increased in Peripheral Artery Disease

C-reactive protein (CRP) as an indicator of cardiovascular disease (CVD) has shown limited sensitivity. We demonstrate that two isoforms of CRP (pentameric, pCRP and monomeric, mCRP) present in soluble form or on microparticles (MPs) have different biological effects and are not all measured by clinical CRP assays. The high-sensitivity CRP assay (hsCRP) did not measure pCRP or mCRP on MPs, whereas flow cytometry did. MPs derived from endothelial cells, particularly those bearing mCRP, were elevated in peripheral artery disease (PAD) patients compared to controls. The numbers of mCRP(+) endothelial MPs did not correlate with hsCRP measurements of soluble pCRP, indicating their independent modulation. In controls, statins lowered mCRP(+) endothelial MPs. In a model of vascular inflammation, mCRP induced endothelial shedding of MPs and was proinflammatory, while pCRP was anti-inflammatory. mCRP on endothelial MPs may be both an unmeasured indicator of, and an amplifier of, vascular disease, and its detection might improve risk sensitivity.

Left Atrial Volume and Pulmonary Artery Diameter Are Noninvasive Measures of Age-Related Diastolic Dysfunction in Mice

Impaired cardiac diastolic function occurs with aging in many species and may be difficult to measure noninvasively. In humans, left atrial (LA) volume is a robust measure of chronic diastolic function as the LA is exposed to increased left ventricular filling pressures. We hypothesized that LA volume would be a useful indicator of diastolic function in aging mice. Further, we asked whether pressures were propagated backwards affecting pulmonary arteries (PAs) and right ventricle (RV). We measured LA, PA, and RV infundibulum dimensions with echocardiography and used mouse-specific Doppler systems and pressure catheters for noninvasive and invasive measures. As C57BL/6 mice aged from 3 to 29-31 months, LA volume almost tripled. LA volume increases correlated with traditional diastolic function measures. Within groups of 14- and 31-month-old mice, LA volume correlated with diastolic function measured invasively. In serial studies, mice evaluated at 20 and 24 months showed monotonic increases in LA volume; other parameters changed less predictably. PA diameters, larger in 30-month-old mice than 6-month-old mice, correlated with LA volumes. Noninvasive LA volume and PA diameter assessments are useful and state independent measures of diastolic function in mice, correlating with other measures of diastolic dysfunction in aging. Furthermore, serial measurements over 4 months demonstrated consistent increases in LA volume suitable for longitudinal cardiac aging studies.

Abstract 76: Effects of Long-term Angiotensin-II Infusion on Cardiac and Renal Fibrosis are Blunted in TNFR1-deficient Mice

Background: Brief systemic infusion of Angiotensin-II (Ang-II) to wild-type (WT) mice initiates the development of cardiac interstitial fibrosis. Genetic deletion of tumor necrosis factor receptor 1 (TNFR1) obviates this development and concurrently inhibits Ang-II-induced cardiac remodeling and dysfunction. We now investigated long-term effects of Ang-II on the heart, kidney, and cardiorenal function.

Methods: WT and TNFR1-KO mice were infused with 1.5 ug/kg/min Ang-II for 1 and 6 weeks (no uninephrectomy or high-salt diet). Heart, kidney, and serum were isolated and evaluated by histology, cytometry, qPCR, and ELISA techniques. Cardiac function was determined by 2D-echocardiography, systolic blood pressure by tail-cuff plethysmography.

Results: Brief infusion of Ang-II to WT mice did not evoke a fibrotic response in the kidney. However, after 6 weeks, WT kidneys developed minimal, but significant interstitial collagen deposition which was supported by upregulation of collagen-I, collagen-III, and alpha-smooth muscle actin gene activation. This fibrotic development was associated with the appearance of myeloid fibroblast precursors, pro-inflammatory M1 and pro-fibrotic M2 cells, and myofibroblasts. Transcriptional expression of pro-inflammatory and pro-fibrotic genes was also increased. These changes were not seen in Ang-II-infused TNFR1-KO kidneys. In WT hearts, despite the disappearance of myeloid cells, cardiac fibrosis persisted throughout the 6-week infusion. WT hearts developed clear evidence of accelerated cardiac hypertrophy and remodeling associated with impaired systolic function. Again, these changes were not seen in Ang-II-infused TNFR1-KO hearts. By contrast, both WT and TNFR1-KO mice responded identically with similar elevations of systolic blood pressure, and serum blood urea nitrogen and creatinine levels.

Conclusions: Ang-II-infusion induced an immediate fibrotic response in the heart while fibrosis in the kidney developed slowly. The cardiac fibrosis was accompanied by progressive adverse remodeling and worsening of function over time. TNFR1-KO mice were protected from the Ang-II-induced cardiac and renal fibrosis, despite similar increases in blood pressure and renal dysfunction.

PHD2/3-dependent hydroxylation tunes cardiac response to β-adrenergic stress via phospholamban

Ischemic heart disease is the leading cause of heart failure. Both clinical trials and experimental animal studies demonstrate that chronic hypoxia can induce contractile dysfunction even before substantial ventricular damage, implicating a direct role of oxygen in the regulation of cardiac contractile function. Prolyl hydroxylase domain (PHD) proteins are well recognized as oxygen sensors and mediate a wide variety of cellular events by hydroxylating a growing list of protein substrates. Both PHD2 and PHD3 are highly expressed in the heart, yet their functional roles in modulating contractile function remain incompletely understood. Here, we report that combined deletion of Phd2 and Phd3 dramatically decreased expression of phospholamban (PLN), resulted in sustained activation of calcium/calmodulin-activated kinase II (CaMKII), and sensitized mice to chronic β-adrenergic stress-induced myocardial injury. We have provided evidence that thyroid hormone receptor-α (TR-α), a transcriptional regulator of PLN, interacts with PHD2 and PHD3 and is hydroxylated at 2 proline residues. Inhibition of PHDs increased the interaction between TR-α and nuclear receptor corepressor 2 (NCOR2) and suppressed Pln transcription. Together, these observations provide mechanistic insight into how oxygen directly modulates cardiac contractility and suggest that cardiac function could be modulated therapeutically by tuning PHD enzymatic activity.

Heart failure with preserved ejection fraction in the elderly: scope of the problem

Heart failure with preserved ejection fraction (HFpEF) is the most common form of heart failure (HF) in older adults, particularly women, and is increasing in prevalence as the population ages. With morbidity and mortality on par with HF with reduced ejection fraction, it remains a most challenging clinical syndrome for the practicing clinician and basic research scientist. Originally considered to be predominantly caused by diastolic dysfunction, more recent insights indicate that HFpEF in older persons is typified by a broad range of cardiac and non-cardiac abnormalities and reduced reserve capacity in multiple organ systems. The globally reduced reserve capacity is driven by: 1) inherent age-related changes; 2) multiple, concomitant co-morbidities; 3) HFpEF itself, which is likely a systemic disorder. These insights help explain why: 1) co-morbidities are among the strongest predictors of outcomes; 2) approximately 50% of clinical events in HFpEF patients are non-cardiovascular; 3) clinical drug trials in HFpEF have been negative on their primary outcomes. Embracing HFpEF as a true geriatric syndrome, with complex, multi-factorial pathophysiology and clinical heterogeneity could provide new mechanistic insights and opportunities for progress in management. This article is part of a Special Issue entitled CV Aging.

High-sensitivity troponin T and cardiovascular events in systolic blood pressure categories: atherosclerosis risk in communities study

Based on observational studies, there is a linear increase in cardiovascular risk with higher systolic blood pressure (SBP), yet clinical trials have not shown benefit across all SBP categories. We assessed whether troponin T measured using high-sensitivity assay was associated with cardiovascular disease within SBP categories in 11 191 Atherosclerosis Risk in Communities study participants. Rested sitting SBP by 10-mm Hg increments and troponin categories were identified. Incident heart failure hospitalization, coronary heart disease, and stroke were ascertained for a median of 12 years after excluding individuals with corresponding disease. Approximately 53% of each type of cardiovascular event occurred in individuals with SBP<140 mm Hg and troponin T ≥3 ng/L. Higher troponin T was associated with increasing cardiovascular events across most SBP categories. The association was strongest for heart failure and least strong for stroke. There was no similar association of SBP with cardiovascular events across troponin T categories. Individuals with troponin T ≥3 ng/L and SBP <140 mm Hg had higher cardiovascular risk compared with those with troponin T <3 ng/L and SBP 140 to 159 mm Hg. Higher troponin T levels within narrow SBP categories portend increased cardiovascular risk, particularly for heart failure. Individuals with lower SBP but measurable troponin T had greater cardiovascular risk compared with those with suboptimal SBP but undetectable troponin T. Future trials of systolic hypertension may benefit by using high-sensitivity troponin T to target high-risk patients.

Hypernatremia in the geriatric population

Hypernatremia in the geriatric population is a common disorder associated with significant morbidity and mortality. Older people are predisposed to developing hypernatremia because of age-related physiologic changes such as decreased thirst drive, impaired urinary concentrating ability, and reduced total body water. Medications may exacerbate this predisposition. Hypernatremia and dehydration occurring in nursing homes are considered indicators of neglect that warrant reporting, but there are other nonavoidable causes of hypernatremia, and consideration at time of presentation is essential to prevent delay in diagnosis and management. We describe a case illustrating the importance of the consideration of alternate explanations for hypernatremia in a nursing home resident, followed by a review of hypernatremia in the elderly population, to underscore that neglect is the etiology of exclusion after alternatives have been considered.

Abstract 215: Angiotensin-II-induced Cardiac Remodeling is Reduced in TNFR1-deficient Mice Despite Increased Blood Pressure

Background: Infusion of angiotensin-II (Ang-II) to wild-type (WT) mice results in hypertension, development of interstitial cardiac fibrosis and hypertrophy, and deterioration of myocardial function. We previously showed that after 1 week of Ang-II infusion, these effects were absent in mice deficient in tumor necrosis factor receptor 1 (TNFR1). We now investigated long-term effects of Ang-II infusion.

Methods: WT and TNFR1-KO mice were infused with Ang-II for 6 weeks. Systolic blood pressure (SBP) was measured by tail-cuff plethysmography; cardiac function by 2D-echocardiography and Doppler ultrasound. Hearts were analyzed for collagen deposition (histology) and expression of fibrosis- and hypertrophy- related genes (quantitative PCR).

Results: In WT mice, SBP increased within 7 days and remained elevated at 6 weeks (152±4 mmHg); cardiac fibrosis developed after 1 week and persisted at 6 weeks (6.2±1.1% collagen area). By contrast, in TNFR1-KO mice, SBP at 7 days was low, but increased by 6 weeks (144±4 mmHg), whereas cardiac fibrosis was absent at 1 week and did not significantly increase by 6 weeks (2.5±0.5%). In support of these data, collagen I and collagen III mRNA expression at 6 weeks were upregulated in WT (2.9±0.6 and 4.1±0.8 -fold over sham), but not in TNFR1-KO hearts (1.3±0.1 and 1.8±0.2). In both mouse groups, cardiac hypertrophy and cardiac dysfunction developed over time, however, these changes were less prominent in TNFR1-KO mice: at 6 weeks, the heart-weight to body-weight ratio in WT was 6.7±0.4, in TNFR1-KO mice 5.5±0.2; the changes in anterior and posterior wall thicknesses in WT were 44±12% and 32±15%, in TNFR1-KO mice 19±8% and 17±10%; the change in ejection fraction in WT was -67±12%, in TNFR1-KO mice -39±5%; and the change in Tei-index (myocardial performance) in WT was 18±9%, in TNFR1-KO -1±7%. Also, hypertrophy-related atrial natriuretic peptide (ANP) and beta-myosin heavy chain (b-MHC) mRNA were upregulated in WT (4.3±0.9 and 4.3±0.6 -fold over sham), but less in TNFR1-KO hearts (2.6±0.5 and 2.4±0.5).

Conclusion: Despite a significant increase in blood pressure over 6 weeks of Ang-II infusion, TNFR1-KO mice developed less cardiac fibrosis and hypertrophy and had better cardiac function compared to WT mice.

Vascular and parenchymal amyloid pathology in an Alzheimer disease knock-in mouse model: interplay with cerebral blood flow

Background

Accumulation and deposition of β-amyloid peptides (Aβ) in the brain is a central event in the pathogenesis of Alzheimer’s disease (AD). Besides the parenchymal pathology, Aβ is known to undergo active transport across the blood–brain barrier and cerebral amyloid angiopathy (CAA) is a prominent feature in the majority of AD. Although impaired cerebral blood flow (CBF) has been implicated in faulty Aβ transport and clearance, and cerebral hypoperfusion can exist in the pre-clinical phase of Alzheimer’s disease (AD), it is still unclear whether it is one of the causal factors for AD pathogenesis, or an early consequence of a multi-factor condition that would lead to AD at late stage. To study the potential interaction between faulty CBF and amyloid accumulation in clinical-relevant situation, we generated a new amyloid precursor protein (APP) knock-in allele that expresses humanized Aβ and a Dutch mutation in addition to Swedish/London mutations and compared this line with an equivalent knock-in line but in the absence of the Dutch mutation, both crossed onto the PS1M146V knock-in background.

Results

Introduction of the Dutch mutation results in robust CAA and parenchymal Aβ pathology, age-dependent reduction of spatial learning and memory deficits, and CBF reduction as detected by fMRI. Direct manipulation of CBF by transverse aortic constriction surgery on the left common carotid artery caused differential changes in CBF in the anterior and middle region of the cortex, where it is reduced on the left side and increased on the right side. However these perturbations in CBF resulted in the same effect: both significantly exacerbate CAA and amyloid pathology.

Conclusions

Our study reveals a direct and positive link between vascular and parenchymal Aβ; both can be modulated by CBF. The new APP knock-in mouse model recapitulates many symptoms of AD including progressive vascular and parenchymal Aβ pathology and behavioral deficits in the absence of APP overexpression.

Considerations for managing chronic obstructive pulmonary disease in the elderly

Chronic obstructive pulmonary disease (COPD) is common in older people, with an estimated prevalence of 10% in the US population aged ≥75 years. Inhaled medications are the cornerstone of treatment for COPD and are typically administered by one of three types of devices, ie, pressurized metered dose inhalers, dry powder inhalers, and nebulizers. However, age-related pulmonary changes may negatively influence the delivery of inhaled medications to the small airways. In addition, physical and cognitive impairment, which are common in elderly patients with COPD, pose special challenges to the use of handheld inhalers in the elderly. Health care providers must take time to train patients to use handheld inhalers and must also check that patients are using them correctly on a regular basis. Nebulizers should be considered for patients unable to use handheld inhalers properly. What follows is a review of issues associated with COPD and its treatment in the elderly patient.

Adverse fibrosis in the aging heart depends on signaling between myeloid and mesenchymal cells; role of inflammatory fibroblasts

Aging has been associated with adverse fibrosis. Here we formulate a new hypothesis and present new evidence that unresponsiveness of mesenchymal stem cells (MSC) and fibroblasts to transforming growth factor beta (TGF-β), due to reduced expression of TGF-β receptor I (TβRI), provides a foundation for cardiac fibrosis in the aging heart via two mechanisms. 1) TGF-β promotes expression of Nanog, a transcription factor that retains MSC in a primitive state. In MSC derived from the aging heart, Nanog expression is reduced and therefore MSC gradually differentiate and the number of mesenchymal fibroblasts expressing collagen increases. 2) As TGF-β signaling pathway components negatively regulate transcription of monocyte chemoattractant protein-1 (MCP-1), a reduced expression of TβRI prevents aging mesenchymal cells from shutting down their own MCP-1 expression. Elevated MCP-1 levels that originated from MSC attract transendothelial migration of mononuclear leukocytes from blood to the tissue. MCP-1 expressed by mesenchymal fibroblasts promotes further migration of monocytes and T lymphocytes away from the endothelial barrier and supports the monocyte transition into macrophages and finally into myeloid fibroblasts. Both myeloid and mesenchymal fibroblasts contribute to fibrosis in the aging heart via collagen synthesis. This article is part of a Special Issue entitled "Myocyte-Fibroblast Signalling in Myocardium ".

microRNA-22 promotes heart failure through coordinate suppression of PPAR/ERR-nuclear hormone receptor transcription

Increasing evidence suggests that microRNAs are intimately involved in the pathophysiology of heart failure. MicroRNA-22 (miR-22) is a muscle-enriched miRNA required for optimum cardiac gene transcription and adaptation to hemodynamic stress by pressure overload in mice. Recent evidence also suggests that miR-22 induces hypertrophic growth and it is oftentimes upregulated in end stage heart failure. However the scope of mRNA targets and networks of miR-22 in the heart failure remained unclear. We analyzed transgenic mice with enhanced levels of miR-22 expression in adult cardiomyocytes to identify important pathophysiologic targets of miR-22. Our data shows that forced expression of miR-22 induces a pro-hypertrophic gene expression program, and it elicits contractile dysfunction leading to cardiac dilation and heart failure. Increased expression of miR-22 impairs the Ca²⁺ transient, Ca²⁺ loading into the sarcoplasmic reticulum plus it interferes with transcription of estrogen related receptor (ERR) and PPAR downstream genes. Mechanistically, miR-22 postranscriptionally inhibits peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α), PPARα and sirtuin 1 (SIRT1) expression via a synergistic circuit, which may account for deleterious actions of unchecked miR-22 expression on the heart.

AICAR-dependent AMPK activation improves scar formation in the aged heart in a murine model of reperfused myocardial infarction

We have demonstrated that scar formation after myocardial infarction (MI) is associated with an endogenous pool of CD44(pos)CD45(neg) multipotential mesenchymal stem cells (MSC). MSC differentiate into fibroblasts secreting collagen that forms a scar and mature into myofibroblasts that express alpha smooth muscle actin (α-SMA) that stabilizes the scar. In the aging mouse, cardiac repair after MI is associated with impaired differentiation of MSC; MSC derived from the aged hearts form dysfunctional fibroblasts that deposit less collagen in response to transforming growth factor beta-1 (TGF-β1) and poorly mature into myofibroblasts. We found in vitro that the defect in myofibroblast maturation can be remedied by AICAR, which activates non-canonical TGF-β signaling through AMP-activated protein kinase (AMPK). In the present study, we injected aged mice with AICAR and subjected them to 1h occlusion of the left anterior descending artery (LAD) and then reperfusion for up to 30days. AICAR-dependent AMPK signaling led to mobilization of an endogenous CD44(pos)CD45(neg) MSC and its differentiation towards fibroblasts and myofibroblasts in the infarct. This was accompanied by enhanced collagen deposition and collagen fiber maturation in the scar. The AICAR-treated group has demonstrated reduced adverse remodeling as indicated by improved apical end diastolic dimension but no changes in ejection fraction and cardiac output were observed. We concluded that these data indicate the novel, previously not described role of AMPK in the post-MI scar formation. These findings can potentially lead to a new therapeutic strategy for prevention of adverse remodeling in the aging heart.