GLYNAC SUPPLEMENTATION IN OLDER ADULTS PROTECTS FROM MEAL DRIVEN OXIDATIVE STRESS AND INFLAMMATION: RESULTS OF A RCT

Elevated oxidative stress (OxS) and inflammation are linked to many age-associated abnormalities, but underlying contributing factors are not well understood. In a randomized clinical trial (RCT) in older adults (OA), we investigated the contribution of a single carbohydrate-meal on OxS and inflammation, and tested the protective effect of supplementing GlyNAC (combination of glycine+N-acetylcysteine) from the meal-driven rise in OxS and inflammation. We studied 20 OA and 10 YA (young-adults) to (1) compare the impact of a 75g oral glucose-meal on plasma markers of OxS (as TBARS) and inflammation (as IL-6); (2) re-assess these outcomes after supplementing OA with either GlyNAC or isonitrogenous placebo (alanine) for 16-weeks, and YA with GlyNAC for 2-weeks. We found that (1) 2-hours after a glucose-meal, compared to YA the OA had higher increases (expressed as percent-change over baseline) of OxS (TBARS –0.1 +/- 0.6 vs. 5.6 +/- 0.6, p < 0.0000) and inflammation (IL-6 3.5 +/- 1.2 vs. 11.2 +/- 0.7, p < 0.0000); (2) GlyNAC supplementation in OA protected against the glucose meal-driven increase in OxS (TBARS pre vs post: 4.8 +/- 0.9 vs. -0.4 +/- 0.8, p=0.002) and inflammation (IL-6 pre vs. post: 10.8 +/- 3.2 vs. 4.2 +/- 2.3, p=0.0001). No improvements occurred in OA receiving placebo or YA receiving GlyNAC. These findings suggest that: (1) In OA, a single carbohydrate-meal significantly increases OxS and inflammation; (2) GlyNAC supplementation protects from carbohydrate meal-driven increases in OxS and inflammation. Additional research to investigate the implications of supplementing GlyNAC on improving meal-related health in aging are warranted.

SUPPLEMENTING GLYNAC IN AGING IMPROVES GLUTATHIONE, MITOCHONDRIA, AND AGING HALLMARKS: A RANDOMIZED CLINICAL TRIAL

Oxidative stress (OxS), mitochondrial dysfunction and aging hallmarks are important contributors to aging, but effective solutions to correct these defects in older adults (OA) are lacking. Via earlier translational studies we discovered that supplementation of GlyNAC (combination of glycine and N-acetylcysteine) improves/corrects these defects. We conducted a double-blind, placebo-controlled (RCT) in 24 OA (mean age 71y) to definitively determine the effects of supplementing GlyNAC vs. isonitrogenous placebo (alanine) for 16-weeks on intracellular glutathione (GSH), OxS mitochondrial function, inflammation, insulin-resistance, endothelial function, physical function, body composition and multiple aging hallmarks. 12 YA (mean age 25y) served as young controls and received GlyNAC for 2-weeks. Subjects were studied before receiving supplementation study, and after receiving supplementation for 2-weeks (OA, YA) and 16-weeks (OA). The RCT found that compared to YA, the OA had severe GSH deficiency (red-cells, muscle), mitochondrial dysfunction, OxS (TBARS, F2-isoprostanes), diminished physical function (gait-speed, muscle strength, exercise capacity), elevated waist-circumference and systolic blood pressure, and multiple hallmarks defects of aging (affecting mitochondrial function, mitophagy, nutrient sensing, inflammation, insulin-resistance, genotoxicity, stem-cells and cellular senescence). GlyNAC supplementation for 2-weeks rapidly improved several defects, and further improved/corrected multiple defects after 16-weeks. No improvements were seen in YA receiving GlyNAC, or in OA receiving the alanine placebo, suggesting that protein supplementation per se in OA does not improve defects. The results of this RCT provides proof-of-concept that GlyNAC supplementation improves/reverses GSH deficiency, mitochondrial dysfunction, OxS, inflammation, physical function/strength and multiple aging hallmarks. GlyNAC could be a novel, simple and safe nutritional supplement to improve/reverse age-associated defects and promote health in aging humans.

Midlife determinants of healthy cardiovascular aging: The Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND AIMS

Risk factor cutoffs are derived from associations with clinical cardiovascular disease (CVD), but how these risk factors associate with preserved cardiovascular health into old age is not well studied. We investigated midlife determinants of healthy versus nonhealthy cardiovascular aging in the Atherosclerosis Risk in Communities (ARIC) study.

METHODS

ARIC participants were categorized by cardiovascular status in older age (mean age 75.8 ± 5.3 years, range 66-90): healthy, subclinical disease (assessed by biomarkers and left ventricular function), clinical CVD (coronary heart disease, stroke, or heart failure), or prior death. We examined associations of midlife (mean age 52.1 ± 5.1 years) systolic and diastolic blood pressure (SBP, DBP), low-density lipoprotein cholesterol (LDL-C), triglycerides, hemoglobin A1c (HbA1c), and body mass index (BMI) with cardiovascular status in older age using multinomial logistic regression analyses.

RESULTS

Compared with healthy status, odds for subclinical disease (odds ratio [OR] 1.30, 95% confidence interval [CI] 1.09-1.55) and clinical CVD (OR 1.87, 95% CI 1.53-2.29) at older age increased starting with midlife SBP 120-129 mmHg, whereas odds for death increased starting with SBP 110-119 mmHg (OR 1.29, 95% CI 1.10-1.52); findings were similar for DBP. Odds for subclinical disease increased for HbA1c ≥ 6.5% and BMI starting at 30-<35 kg/m2; odds for clinical CVD or death increased starting at HbA1c 5.5-5.9%, LDL-C >160 mg/dL, and BMI 30-<35 kg/m2.

CONCLUSIONS

More-stringent levels of modifiable risk factors in midlife beyond current clinical practice and guidelines were associated with preserved cardiovascular health in older age.

Diagnostic accuracy of the 4AT for delirium detection in older adults: systematic review and meta-analysis

OBJECTIVE

Detection of delirium in hospitalised older adults is recommended in national and international guidelines. The 4 'A's Test (4AT) is a short (<2 minutes) instrument for delirium detection that is used internationally as a standard tool in clinical practice. We performed a systematic review and meta-analysis of diagnostic test accuracy of the 4AT for delirium detection.

METHODS

We searched MEDLINE, EMBASE, PsycINFO, CINAHL, clinicaltrials.gov and the Cochrane Central Register of Controlled Trials, from 2011 (year of 4AT release on the website www.the4AT.com) until 21 December 2019. Inclusion criteria were: older adults (≥65 years); diagnostic accuracy study of the 4AT index test when compared to delirium reference standard (standard diagnostic criteria or validated tool). Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Pooled estimates of sensitivity and specificity were generated from a bivariate random effects model.

RESULTS

Seventeen studies (3,702 observations) were included. Settings were acute medicine, surgery, a care home and the emergency department. Three studies assessed performance of the 4AT in stroke. The overall prevalence of delirium was 24.2% (95% CI 17.8-32.1%; range 10.5-61.9%). The pooled sensitivity was 0.88 (95% CI 0.80-0.93) and the pooled specificity was 0.88 (95% CI 0.82-0.92). Excluding the stroke studies, the pooled sensitivity was 0.86 (95% CI 0.77-0.92) and the pooled specificity was 0.89 (95% CI 0.83-0.93). The methodological quality of studies varied but was moderate to good overall.

CONCLUSIONS

The 4AT shows good diagnostic test accuracy for delirium in the 17 available studies. These findings support its use in routine clinical practice in delirium detection.

PROSPERO REGISTRATION NUMBER

CRD42019133702.

33 Diagnostic Test Accuracy of the 4AT for Delirium Detection: Systematic Review and Meta-Analysis

Introduction

Detection of delirium in hospitalised older adults is recommended in national and international guidelines. The 4 ‘A’s Test (4AT; www.the4AT.com) is a short (&lt;2 min) instrument for delirium detection that is used internationally as a standard tool in clinical practice. We performed a systematic review and meta-analysis of diagnostic test accuracy of the 4AT for delirium detection.

Methods

We searched the following electronic databases through Ovid: MEDLINE, Embase, and PsycINFO. Additional databases were searched: CINAHL (EBSCOhost), clinicaltrials.gov and Cochrane Central Register of Controlled Trials from 2011 (4AT publication) until 21 December 2019. Inclusion criteria: older adults (≥65) across any setting of care except critical care; validation study of the 4AT against a delirium reference standard (standard diagnostic criteria or validated tool). Two reviewers independently screened abstracts and papers and performed the data extraction. Pooled estimates of sensitivity and specificity were generated from a bivariate random effects model.

Results

17 studies (n = 3,701 observations) were included. Various settings including acute medicine, surgery, stroke wards and the emergency department were represented. The overall prevalence of delirium was 24.2% (95% CI 17.8–32.1%; range 10.5–61.9%). The pooled sensitivity was 0.88 (95% CI 0.80–0.93) and the pooled specificity was 0.88 (95% CI 0.82–0.92). The methodological quality of studies was mostly good.

Conclusions

The 4AT is now supported by a substantial evidence base comparable to other well-studied tools such as the Confusion Assessment Method (CAM). The strong pooled sensitivity and specificity findings for the 4AT in this meta-analysis along with its brevity and lack of need for specific training provide support for its use as an effective assessment tool for delirium.

Multicomponent Interventions Reduce High-Risk Medications for Delirium in Hospitalized Older Adults

Delirium threatens the functional independence and cognitive capacity of patients. Medications, especially those with strong anticholinergic effects, have been implicated as a preventable cause of delirium. We evaluated the effect of multicomponent interventions aimed at reducing the use of 9 target medications in hospitalized older adults at risk of delirium. This continuous quality improvement program was undertaken at a tertiary care facility and 4 community hospitals in a hospital system. We included 21, 541 hospital admissions with patients aged 70 and older on acute care medical or surgical units from the preintervention (2012) period, and 27,764 from the postintervention (2015) period. Implemented interventions include formulary and policy changes, technology-assisted medication review, age-conditional order set modifications, best practice alerts, and education. The proportion of hospital admissions with individual's receiving at least 1 target medication declined from 45.6% to 31.3% (relative reduction (RR)=31.4%) from before to after the intervention, meaning that target medication exposure was avoided in approximately 4,000 older adults. The greatest effect was observed for zolpidem (11.2% to 5.3%, RR=52.6%) and diphenhydramine (12.9% to 7.1%, RR=45%). Furthermore, the mean number of doses administered during all hospital admissions was reduced for 7 of 9 medications. Multicomponent interventions implemented in our hospital system were effective at reducing exposure to target medications in hospitalized older adults at risk of delirium. These systematic changes applied throughout the medication use process are sustained today.

Measures of Healthspan as Indices of Aging in Mice-A Recommendation

Over the past decade, a large number of discoveries have shown that interventions (genetic, pharmacological, and nutritional) increase the lifespan of invertebrates and laboratory rodents. Therefore, the possibility of developing antiaging interventions for humans has gone from a dream to a reality. However, it has also become apparent that we need more information than just lifespan to evaluate the translational potential of any proposed antiaging intervention to humans. Information is needed on how an intervention alters the "healthspan" of an animal, that is, how the physiological functions that change with age are altered. In this report, we describe the utility and the limitations of assays in mice currently available for measuring a wide range of physiological functions that potentially impact quality of life. We encourage investigators and reviewers alike to expect at minimum an overall assessment of health in several domains across several ages before an intervention is labeled as "increasing healthspan." In addition, it is important that investigators indicate any tests in which the treated group did worse or did not differ statistically from controls because overall health is a complex phenotype, and no intervention discovered to date improves every aspect of health. Finally, we strongly recommend that functional measurements be performed in both males and females so that sex differences in the rate of functional decline in different domains are taken into consideration.

Application of speckle-tracking in the evaluation of carotid artery function in subjects with hypertension and diabetes

BACKGROUND

Speckle-tracking enables direct tracking of carotid arterial wall motion. Timing intervals determined with carotid speckle-tracking and slopes calculated from carotid artery area versus cardiac cycle curves may provide further information on arterial function and stiffness. The proposed arterial stiffness parameters were examined in healthy controls (n = 20), nondiabetic patients with hypertension (n = 20), and patients with type 2 diabetes (n = 21).

METHODS

Bilateral electrocardiographically gated ultrasonograms of the distal common carotid artery were acquired using a 12-MHz vascular probe. Four timing intervals were derived from speckle-tracked carotid arterial strain curves: (1) carotid predistension period, (2) peak carotid arterial strain time, (3) arterial distension period, and (4) arterial diastolic time. In addition, carotid artery area curves were recorded over the cardiac cycle and subdivided into four segments, S1 to S4, relating to arterial distention and contraction periods.

RESULTS

Mean far wall predistension period and peak carotid arterial strain time were more delayed in patients with diabetes and hypertension than in controls. Global mean arterial distension period was prolonged and arterial diastolic time was shorter in patients with hypertension and diabetes than in controls. Slopes of segments S2 and S4 were markedly steeper in the combined group of patients with hypertension and diabetes compared with healthy controls (P = .03 and P = .02, respectively).

CONCLUSIONS

Speckle-tracking-based measures of arterial stiffness may provide potential additive value in assessing vascular function in patients at risk for cardiovascular disease.

Characterization of arterial wave propagation and reflection in mice

Wave propagation through the arterial system changes with age and disease state, and mutant mice are often used to study these conditions. We have developed several noninvasive ultrasonic techniques to measure blood velocity and vessel wall motion from which we can calculate aortic pulse wave velocity (PWV), local compliance, impedance spectra, characteristic impedance (Z<inf>c</inf>), augmentation index (AI), and forward and backward waves in intact anesthetized mice. We found altered vascular mechanics in many mutant strains of mice. In old mice PWV, AI, and Z<inf>c</inf>are increased. In atherosclerotic mice PWV, Zc, and AI are increased; peripheral resistance and arterial compliance are decreased; and wave reflections are enhanced. We find that the initial deceleration of carotid velocity is caused by peripheral reflections, and that increased acceleration of velocity in the aortic arch in atherosclerotic mice is caused by enhanced carotid reflections returning to the heart and traveling forward in the aorta. We conclude that when scaled for heart period, the mouse arterial system and its responses to age and disease are similar to those in man. The ability to evaluate arterial mechanics in mice will expand their use as models to study human arterial diseases and conditions.

An online spaced-education game to teach and assess medical students: a multi-institutional prospective trial

PURPOSE

To investigate whether a spaced-education (SE) game can be an effective means of teaching core content to medical students and a reliable and valid method of assessing their knowledge.

METHOD

This nine-month trial (2008-2009) enrolled students from three U.S. medical schools. The SE game consisted of 100 validated multiple-choice questions-explanations in preclinical/clinical domains. Students were e-mailed two questions daily. Adaptive game mechanics re-sent questions in three or six weeks if answered, respectively, incorrectly or correctly. Questions expired if not answered on time (appointment dynamic). Students retired questions by answering each correctly twice consecutively (progression dynamic). Posting of relative performance fostered competition. Main outcome measures were baseline and completion scores.

RESULTS

Seven-hundred thirty-one students enrolled. Median baseline score was 53% (interquartile range [IQR] 16) and varied significantly by year (P<.001, dmax=2.08), school (P<.001, dmax=0.75), and gender (P<.001, d=0.38). Median completion score was 93% (IQR 12) and varied significantly by year (P=.001, dmax=1.12), school (P<.001, dmax=0.34), and age (P=.019, dmax=0.43). Scores did not differ significantly between years 3 and 4. Seventy percent of enrollees (513/731) requested to participate in future SE games.

CONCLUSIONS

An SE game is an effective and well-accepted means of teaching core content and a reliable and valid method to assess student knowledge. SE games may be valuable tools to identify and remediate students who could benefit from additional educational support.

Abstract 68: Role of Substance P Signaling in the Pathogenesis of Murine Viral Myocarditis

Viral myocarditis is an important cause of heart failure in adolescents and young adults for which no specific treatment is currently available. Substance P (SP) is a neuropeptide and pain transmitter that activates RhoA, a small G-protein, shown to induce hypertrophy of neonatal rat ventricular myocytes. The current studies were performed to determine if SP signaling contributes to the pathogenesis of encephalomyocarditis virus (EMCV) infection, a well-established murine model of viral myocarditis. Aprepitant (1.2 mg/kg), a SP receptor antagonist, or fasudil (10mg/kg), a Rho A inhibitor, or saline control, was administered daily to mice orally by gavage 3 times for 3 days prior to intraperitoneal infection with 50 PFU of EMCV, and the mice monitored for 14 days. Pretreatment with aprepitant reduced mortality by 40% (25±7% vs. 65±7%), reduced heart-to-body weight ratio by 26% (0.0088±0.0001 vs. 0.0119±0.0001), reduced end systolic diameter (ESD) by 21% (3.0±0.2mm vs. 3.8±0.4mm), improved ejection fraction by 72% (57.2±4.7% vs. 33.2 ±9.3%), reduced chamber volume by 46% (34±5.0 μl vs. 62.7±30.8 μl), increased peak aortic flow velocity by 41% (87.0±24.7 vs. 61.7±20.1), and reduced cardiomyocyte diameter size by13% (11.0±0.1 μM vs. 12.7± 0.2 μM); p<.05 for all, Student’s t-test). Pretreatment with fasudil reduced heart-to-body weight ratio by 18% (0.0097±0.0001 vs. 0.0119±0.0001) and reduced cardiomyocyte diameter size by 12% (11.14±0.51 μM vs. 12.7± 0.2 μM; p<.05 for both), but did not significantly impact heart functional changes or mortality. These findings indicate that SP contributes to cardiac remodeling and dysfunction following ECMV infection and raises the possibility that inhibition of SP signaling may be of benefit in the treatment of patients with viral myocarditis.

Abstract P158: MicroRNA-22 Modulates Cardiac Gene Expression and Controls Compensation to Hemodynamic Stress in Mice

Recent evidence suggests that miRNAs play an important role in cardiac morphogenesis and pathophyiology of heart failure. To explore the role of miR-22 in the mouse heart physiology, we generated miR-22 null (KO) mice. Although, miR-22 KO mice showed normal cardiac structure and function at baseline, these mice are sensitized to maladaptive remodeling (cardiac dilation) and decompensation in response to pressure overload by transverse aortic constrictions (TAC) stimulation. Genome-wide molecular analysis of KO hearts revealed attenuated expression of numerous CarG-dependent genes encoding proteins that reside at the sarcomeric Z-disc (including Myh7, Acta1, Mlp, Melusin, MyoZ2) indicating that miR-22 is required for optimum muscle gene expression. Alterations in sarcomeric gene expression is especially interesting as this suggests a primary role of miR-22 in controlling cardiac contractility and adaptation to stress. Targetomics analysis revealed that mechanistically this effect could be modulated in part by miR-22 target PURB (Purine Rich element binding protein B), a transcriptional/translational repressor.

In conclusion we define a critical role of miR-22 in cardiac adaptation to hemodynamic stress. Furthermore, these data provides a previously unseen essential molecular mechanism that underlies homeostatic control of sarcomeric protein expression in the heart.

Adipokines in patients with cancer anorexia and cachexia

BACKGROUND

Anorexia, cachexia, and insulin resistance are commonly seen in patients with cancer. Adipocyte-derived hormones or adipokines play a role in the regulation of appetite, body weight, and insulin sensitivity. However, their role in cancer-induced cachexia has not been well-established. The objective of this study was to determine the levels of adipokines and their relation to appetite, weight loss, insulin resistance, and other hormones in cancer cachexia.

METHODS

We measured adiponectin, resistin, and leptin plasma levels in 21 men with cancer cachexia, 24 noncachectic cancer subjects, and 25 noncancer controls matched by age, sex, and pre-illness body weight. Body weight change, appetite scores, insulin resistance assessed by homeostasis model assessment, and other cytokines and hormones were also measured. Differences between groups were measured by analysis of covariance. Relations between variables were examined by linear regression analyses.

RESULTS

Adiponectin levels were similarly elevated in cachectic and noncachectic cancer patients compared with noncancer controls. Leptin levels were significantly decreased in cancer cachexia and were directly associated with appetite and insulin resistance, explaining 37% and 19% of the variance seen in cancer patients, respectively. Resistin levels were not different between groups.

CONCLUSIONS

Leptin may play a role in the increased insulin resistance seen in cancer patients. However, these patients are resistant to the orexigenic effects of hypoleptinemia. Other mechanisms besides weight loss are responsible for the increased adiponectin level seen in cancer patients. It is unlikely that resistin plays a major metabolic role in this setting.

Aging-related defects are associated with adverse cardiac remodeling in a mouse model of reperfused myocardial infarction

OBJECTIVES

The purpose of this study was to study aging-associated alterations in the inflammatory and reparative response after myocardial infarction (MI) and their involvement in adverse post-infarction remodeling of the senescent heart.

BACKGROUND

Advanced age is a predictor of death and ventricular dilation in patients with MI; however, the cellular mechanisms responsible for increased remodeling of the infarcted senescent heart remain poorly understood.

METHODS

Histomorphometric, molecular, and echocardiographic end points were compared between young and senescent mice undergoing reperfused infarction protocols. The response of young and senescent mouse cardiac fibroblasts to transforming growth factor (TGF)-beta stimulation was examined.

RESULTS

Senescence was associated with decreased and delayed neutrophil and macrophage infiltration, markedly reduced cytokine and chemokine expression in the infarcted myocardium, and impaired phagocytosis of dead cardiomyocytes. Reduced inflammation in senescent mouse infarcts was followed by decreased myofibroblast density and markedly diminished collagen deposition in the scar. The healing defects in senescent animals were associated with enhanced dilative and hypertrophic remodeling and worse systolic dysfunction. Fibroblasts isolated from senescent mouse hearts showed a blunted response to TGF-beta1.

CONCLUSIONS

Although young mice exhibit a robust post-infarction inflammatory response and form dense collagenous scars, senescent mice show suppressed inflammation, delayed granulation tissue formation, and markedly reduced collagen deposition. These defects might contribute to adverse remodeling. These observations suggest that caution is necessary when attempting to therapeutically target the post-infarction inflammatory response in patients with reperfused MI. The injurious potential of inflammatory mediators might have been overstated, owing to extrapolation of experimental findings from young animals to older human patients.

Essential role of Smad3 in infarct healing and in the pathogenesis of cardiac remodeling

BACKGROUND

Postinfarction cardiac repair is regulated through timely activation and repression of inflammatory pathways, followed by transition to fibrous tissue deposition and formation of a scar. The transforming growth factor-beta/Smad3 pathway is activated in healing infarcts and may regulate cellular events critical for the inflammatory and the fibrotic responses.

METHODS AND RESULTS

We examined the effects of Smad3 gene disruption on infarct healing and the pathogenesis of cardiac remodeling. In the absence of injury, Smad3-null hearts had comparable function to and similar morphology as wild-type hearts. Smad3-null animals had suppressed peak chemokine expression and decreased neutrophil recruitment in the infarcted myocardium but showed timely repression of inflammatory gene synthesis and resolution of the inflammatory infiltrate. Although myofibroblast density was higher in Smad3-null infarcts, interstitial deposition of collagen and tenascin-C in the remodeling myocardium was markedly reduced. Compared with wild-type animals, Smad3-/- mice exhibited decreased dilative remodeling and attenuated diastolic dysfunction; however, infarct size was comparable between groups. Transforming growth factor-beta-mediated induction of procollagen type III and tenascin-C in isolated cardiac fibroblasts was dependent on Smad3, which suggests that decreased fibrotic remodeling in infarcted Smad3-null hearts may be due to abrogation of the profibrotic transforming growth factor-beta responses.

CONCLUSIONS

Smad3 loss does not alter the time course of resolution of inflammation in healing infarcts, but it prevents interstitial fibrosis in the noninfarcted myocardium and attenuates cardiac remodeling. Thus, the Smad3 cascade may be a promising therapeutic target for the treatment of myocardial infarction.

Elevation of RNA-binding protein CUGBP1 is an early event in an inducible heart-specific mouse model of myotonic dystrophy

Myotonic dystrophy type 1 (DM1) is caused by a CTG trinucleotide expansion in the 3' untranslated region (3' UTR) of DM protein kinase (DMPK). The key feature of DM1 pathogenesis is nuclear accumulation of RNA, which causes aberrant alternative splicing of specific pre-mRNAs by altering the functions of CUG-binding proteins (CUGBPs). Cardiac involvement occurs in more than 80% of individuals with DM1 and is responsible for up to 30% of disease-related deaths. We have generated an inducible and heart-specific DM1 mouse model expressing expanded CUG RNA in the context of DMPK 3' UTR that recapitulated pathological and molecular features of DM1 including dilated cardiomyopathy, arrhythmias, systolic and diastolic dysfunction, and mis-regulated alternative splicing. Combined in situ hybridization and immunofluorescent staining for CUGBP1 and CUGBP2, the 2 CUGBP1 and ETR-3 like factor (CELF) proteins expressed in heart, demonstrated elevated protein levels specifically in nuclei containing foci of CUG repeat RNA. A time-course study demonstrated that colocalization of MBNL1 with RNA foci and increased CUGBP1 occurred within hours of induced expression of CUG repeat RNA and coincided with reversion to embryonic splicing patterns. These results indicate that CUGBP1 upregulation is an early and primary response to expression of CUG repeat RNA.

Is aortic impedance altered in dwarf mice?

Dwarf mouse (deficient in growth hormone and insulin-like growth factor-1) lives about 30% longer than wild type mice. However, very little is known about their cardiovascular physiology. We examined the aortic input impedance in dwarf mice and their wild-type littermates to evaluate any differences. Aortic impedance was determined using pressure and velocity signals which are independent of body size. Significant differences were observed in the body weight, aortic systolic, diastolic and mean pressures, and peak and mean aortic flow velocities. No differences were observed in impedance parameters of peripheral resistance, impedance at first harmonic, and characteristic impedance between the two groups. However, the impedance curve in the dwarf mice was higher at low frequency and decreased gradually with increasing frequencies but in the wild type mice the impedance curve oscillated around the characteristic impedance.

Critical Role of Monocyte Chemoattractant Protein-1/CC Chemokine Ligand 2 in the Pathogenesis of Ischemic Cardiomyopathy

Background— Cardiac interstitial fibrosis plays an important role in the pathogenesis of ischemic cardiomyopathy, contributing to systolic and diastolic dysfunction. We have recently developed a mouse model of fibrotic noninfarctive cardiomyopathy due to brief repetitive myocardial ischemia and reperfusion. In this model, fibrotic changes are preceded by marked and selective induction of the CC chemokine monocyte chemoattractant protein-1 (MCP-1). We hypothesized that MCP-1 may mediate fibrotic remodeling through recruitment of mononuclear cells and direct effects on fibroblasts.

Methods and Results— Wild-type (WT) and MCP-1-null mice underwent daily 15-minute coronary occlusions followed by reperfusion. Additional WT animals received intraperitoneal injections of a neutralizing anti-MCP-1 antibody after the end of each ischemic episode. Hearts were examined echocardiographically and processed for histological and RNA studies. WT mice undergoing repetitive brief myocardial ischemia and reperfusion protocols exhibited macrophage infiltration after 3 to 5 days and marked interstitial fibrosis in the ischemic area after 7 days, accompanied by ventricular dysfunction. MCP-1-null mice had markedly diminished interstitial fibrosis, lower macrophage infiltration, and attenuated ventricular dysfunction compared with WT animals. MCP-1 neutralization also inhibited interstitial fibrosis, decreasing left ventricular dysfunction and regional hypocontractility. Cardiac myofibroblasts isolated from WT but not from MCP-1-null animals undergoing repetitive myocardial ischemia and reperfusion demonstrated enhanced proliferative capacity. However, MCP-1 stimulation did not induce cardiac myofibroblast proliferation and did not alter expression of fibrosis-associated genes.

Conclusions— Defective MCP-1 signaling inhibits the development of ischemic fibrotic cardiomyopathy in mice. The profibrotic actions of MCP-1 are associated with decreased macrophage recruitment and may not involve direct effects on cardiac fibroblasts.

Ménage-à-trois 1 is critical for the transcriptional function of PPARgamma coactivator 1

The Cdk7/cyclin H/ménage-à-trois 1 (MAT1) heterotrimer has proposed functions in transcription as the kinase component of basal transcription factor TFIIH and is activated in adult hearts by Gq-, calcineurin-, and biomechanical stress-dependent pathways for hypertrophic growth. Using cardiac-specific Cre, we have ablated MAT1 in myocardium. Despite reduced Cdk7 activity, MAT1-deficient hearts grew normally, but fatal heart failure ensued at 6-8 weeks. By microarray profiling, quantitative RT-PCR, and western blotting at 4 weeks, genes for energy metabolism were found to be suppressed selectively, including targets of peroxisome proliferator-activated receptor gamma coactivator 1 (PGC-1). Cardiac metabolic defects were substantiated in isolated perfused hearts and isolated mitochondria. In culture, deleting MAT1 with Cre disrupted PGC-1 function: PGC-1alpha failed to activate PGC-1-responsive promoters and nuclear receptors, GAL4-PGC-1alpha was functionally defective, and PGC-1beta was likewise deficient. PGC-1 bound to both MAT1 and Cdk7 in coprecipitation assays. Thus, we demonstrate a requirement for MAT1 in the operation of PGC-1 coactivators that control cell metabolism.

Interleukin-10 is not a critical regulator of infarct healing and left ventricular remodeling

OBJECTIVE

Interleukin-10 (IL-10) exerts potent anti-inflammatory actions and modulates matrix metalloproteinase expression. We hypothesized that endogenous IL-10 may regulate infarct healing and left ventricular remodeling by promoting resolution of the post-infarction inflammatory response and by modulating extracellular matrix metabolism.

METHODS

IL-10 null and wildtype (WT) mice underwent reperfused infarction protocols. We compared the healing response and remodeling-associated parameters between IL-10-/-and WT infarcts. In addition, we studied the effects of IL-10 on inflammatory gene synthesis by stimulated murine cardiac fibroblasts.

RESULTS

Infarcted IL-10-/-mice exhibited comparable mortality rates with WT animals. Although IL-10-/-mice had higher peak tumor necrosis factor (TNF)-alpha and monocyte chemoattractant protein (MCP)-1/CCL2 mRNA levels in the infarcted heart than WT mice, both groups demonstrated timely repression of pro-inflammatory cytokine and chemokine mRNA synthesis after 24 h of reperfusion and exhibited a similar time course of resolution of the neutrophil infiltrate. IL-10 gene disruption did not alter fibrous tissue deposition and dilative remodeling of the infarcted heart. Pre-incubation with IL-10 did not modulate the pro-inflammatory phenotype of TNF-alpha-stimulated cardiac fibroblasts, failing to inhibit chemokine mRNA synthesis. In contrast, transforming growth factor (TGF)-beta1 pre-incubation suppressed interferon-gamma-inducible protein (IP)-10/CXCL10 synthesis by cardiac fibroblasts exposed to TNF-alpha.

CONCLUSIONS

IL-10 signaling plays a non-critical role in suppression of inflammatory mediators, resolution of the inflammatory response, and fibrous tissue deposition following myocardial infarction. This may be due to the relative selectivity of IL-10-mediated anti-inflammatory actions, with respect to cell type and stimulus. Resolution of post-infarction inflammation is likely to involve multiple overlapping regulatory mechanisms controlling various pro-inflammatory pathways activated in the infarcted myocardium.

Effects of diet-induced obesity on inflammation and remodeling after myocardial infarction

Epidemiological studies indicate that obesity, insulin resistance, and diabetes are important comorbidities of patients with ischemic heart disease and increase mortality and development of congestive heart failure after myocardial infarction. Although ob/ob and db/db mice are commonly used to study obesity with insulin resistance or diabetes, mutations in the leptin gene or its receptor are rarely the cause of obesity in humans, which is, instead, primarily a consequence of dietary and lifestyle factors. Therefore, we used a murine model of diet-induced obesity to examine the physiological effects of obesity and the inflammatory and healing response of diet-induced obese (DIO) mice after myocardial ischemia-reperfusion injury. DIO mice developed hyperinsulinemia and insulin resistance and hepatic steatosis, with significant ectopic lipid deposition in the heart and cardiac hypertrophy in the absence of significant changes in blood pressure. The mRNA levels of chemokines at 24 h and cytokines at 24 and 72 h of reperfusion were higher in DIO than in lean mice. In granulation tissue at 72 h of reperfusion, macrophage density was significantly increased, whereas neutrophil density was reduced, in DIO mice compared with lean mice. At 7 days of reperfusion, collagen deposition in the scar was significantly reduced and left ventricular (LV) dilation and cardiac hypertrophy were increased, indicative of adverse LV remodeling, in infarcted DIO mice. Characterization of a murine diet-induced model of obesity and insulin resistance that satisfies many aspects commonly observed in human obesity allows detailed examination of the adverse cardiovascular effects of diet-induced obesity at the molecular level.

Cardiac tissue-specific repression of CELF activity disrupts alternative splicing and causes cardiomyopathy

Members of the CELF family of RNA binding proteins have been implicated in alternative splicing regulation in developing heart. Transgenic mice that express a nuclear dominant-negative CELF protein specifically in the heart (MHC-CELFDelta) develop cardiac hypertrophy and dilated cardiomyopathy with defects in alternative splicing beginning as early as 3 weeks after birth. MHC-CELFDelta mice exhibit extensive cardiac fibrosis, severe cardiac dysfunction, and premature death. Interestingly, the penetrance of the phenotype is greater in females than in males despite similar levels of dominant-negative expression, suggesting that there is sex-specific modulation of splicing activity. The cardiac defects in MHC-CELFdelta mice are directly attributable to reduced levels of CELF activity, as crossing these mice with mice overexpressing CUG-BP1, a wild-type CELF protein, rescues defects in alternative splicing, the severity and incidence of cardiac hypertrophy, and survival. We conclude that CELF protein activity is required for normal alternative splicing in the heart in vivo and that normal CELF-mediated alternative splicing regulation is in turn required for normal cardiac function.

Active ghrelin levels and active to total ghrelin ratio in cancer-induced cachexia

Anorexia and weight loss are negative prognostic factors in patients with cancer. Although total ghrelin levels are increased in energy-negative states, levels of the biologically active octanoylated ghrelin and the anorexigenic peptide YY (PYY) have not been reported in patients with cancer-induced cachexia. We hypothesized that abnormal ghrelin and/or PYY levels contribute to cancer-induced cachexia. We evaluated 21 patients with cancer-induced cachexia; 24 cancer patients without cachexia; and 23 age-, sex-, race-, and BMI-matched subjects without cancer. Active ghrelin levels and the active to total ghrelin ratio were significantly increased in subjects with cancer-induced cachexia, compared with cancer and noncancer controls. PYY levels were similar among groups. Appetite measured by a visual analog scale was not increased in subjects with cachexia. The increase in active ghrelin levels is likely to be a compensatory response to weight loss. Cachexia may be a state of ghrelin resistance because appetite does not correlate with ghrelin levels. Changes in the active to total ghrelin ratio suggest that a mechanism other than increased secretion must be responsible for the increase in active ghrelin levels. PYY is unlikely to play an important role in cancer-induced cachexia.

A murine model of ischemic cardiomyopathy induced by repetitive ischemia and reperfusion

BACKGROUND

Repetitive brief myocardial ischemia has been implicated in the pathogenesis of the ventricular dysfunction associated with ischemic cardiomyopathy and myocardial hibernation. In this study we examine the effects of repetitive ischemia and reperfusion (I/R) on murine myocardium.

METHODS

C57/BL6 mice underwent daily 15 min left anterior descending coronary occlusions followed by reperfusion. After 3, 5, 7, 14, 21 and 28 days, echocardiographic studies were performed, and hearts of I/R and sham-operated animals were processed for histological examination.

RESULTS

Histological studies showed no evidence of myocardial necrosis in the ischemic region. Quantitative assessment of collagen revealed a marked persistent interstitial deposition of collagen after seven days I/R in the anterior left ventricular wall (sham 4.6 +/- 2.0 %, I/R 21.5 +/- 6.5 %, p < 0.05). Echocardiographic studies showed persistent regional anterior wall dysfunction in I/R animals. Histological evaluation showed absence of neovessel formation. After discontinuation of the I/R protocol, fibrosis and regional ventricular dysfunction decreased within 60 days.

CONCLUSIONS

Repetitive brief murine myocardial I/R induces reversible fibrotic remodeling and ventricular dysfunction, without myocardial infarction and necrosis, and may play a role in the pathogenesis of ischemic cardiomyopathy and myocardial hibernation.

Development of murine ischemic cardiomyopathy is associated with a transient inflammatory reaction and depends on reactive oxygen species

We examined the effects of daily repetitive brief (15 min) myocardial ischemia and reperfusion (I/R) in WT C57BL6 and extracellular superoxide dismutase (EC-SOD)-overexpressing mice. In the absence of myocardial necrosis, I/R resulted in persistent fibrosis in ischemic areas of C57/BL6 mice associated with persistent global and segmental anterior wall dysfunction. The I/R protocol induced chemokines (peak 3 days) followed sequentially by infiltration of macrophages and myofibroblasts (5 days). Fibrosis peaked at 7 days and was stable at 28 days despite regression of the chemokine and cellular response. Discontinuation of I/R at 7 or 28 days led to regression of fibrosis and ventricular dysfunction. In contrast, the EC-SOD mice developed markedly less chemokine induction, cell response, and fibrosis, with no ventricular dysfunction. Reversible fibrosis and ventricular dysfunction are features of human hibernating myocardium. The reduction of the cellular and functional response in EC-SOD mice suggests a role for reactive O(2) in the pathogenesis of ischemic cardiomyopathy.

Impaired vascular contractility and blood pressure homeostasis in the smooth muscle alpha-actin null mouse

The smooth muscle (SM) alpha-actin gene activated during the early stages of embryonic cardiovascular development is switched off in late stage heart tissue and replaced by cardiac and skeletal alpha-actins. SM alpha-actin also appears during vascular development, but becomes the single most abundant protein in adult vascular smooth muscle cells. Tissue-specific expression of SM alpha-actin is thought to be required for the principal force-generating capacity of the vascular smooth muscle cell. We wanted to determine whether SM alpha-actin gene expression actually relates to an actin isoform's function. Analysis of SM alpha-actin null mice indicated that SM alpha-actin is not required for the formation of the cardiovascular system. Also, SM alpha-actin null mice appeared to have no difficulty feeding or reproducing. Survival in the absence of SM alpha-actin may result from other actin isoforms partially substituting for this isoform. In fact, skeletal alpha-actin gene, an actin isoform not usually expressed in vascular smooth muscle, was activated in the aortas of these SM alpha-actin null mice. However, even with a modest increase in skeletal alpha-actin activity, highly compromised vascular contractility, tone, and blood flow were detected in SM alpha-actin-defective mice. This study supports the concept that SM alpha-actin has a central role in regulating vascular contractility and blood pressure homeostasis, but is not required for the formation of the cardiovascular system.

Considerations related to disability and exercise in elderly women with congestive heart failure

Congestive heart failure is one of the most common diagnoses in older women. This article reviews physiologic and pathophysiologic factors that contribute to disability in older women with normal left ejection fraction congestive heart failure; the possibility that aerobic exercise training may be an effective means to reduce the disability experienced by these women is examined. Most literature has dealt with low-output ejection fraction congestive heart failure. Comparisons between low-output ejection fraction congestive heart failure and normal left ejection fraction congestive heart failure can help to clarify beneficial interventions. A physiologic model is proposed that includes peripheral and cardiac factors caused by heart disease, and factors caused by aging, that may account for increasing the disabling consequences and reducing exercise tolerance of older women with normal left ejection fraction congestive heart failure. The potential impact of exercise training on these factors is discussed. Directions for practice and further research are included.

Canine cardiac sarcoplasmic reticulum is not altered with endurance exercise training

To investigate the effect of exercise training on calcium movements by isolated cardiac sarcoplasmic reticulum (SR), mongrel dogs either remained sedentary (S) or were exercise-trained (E) via running for a period of 8-10 wk. The trained state was confirmed by the increase in skeletal muscle citrate synthase activity and decreases in submaximal exercise heart rates in the E group but not in the S dogs. The properties of isolated cardiac SR were identical between the groups. The variables tested included ATP-dependent calcium transport and calcium-stimulated ATPase activity. Importantly, there was no difference in spontaneous calcium release which occurred after peak ATP-dependent calcium accumulation was reached. Calcium release from passively loaded vesicles induced by calcium and ionophore also did not differ in the SR isolated from the E dogs. The change in the affinity of the SR Ca ATPase for calcium after the addition of the polyanion, heparin, was similar in both groups, indicating that the regulation of calcium-stimulated ATPase activity by the SR protein, phospholamban, is not modified by exercise training. We conclude that exercise training of 8-10 wk duration does not alter the calcium handling properties of cardiac SR isolated from mongrel dogs.

Educating the elderly: cardiopulmonary resuscitation decisions before and after intervention

Considering the limited success of cardiopulmonary resuscitation (CPR) in achieving survival to hospital discharge in older persons, it is appropriate to educate, discuss and determine patients' wishes at a time when they are able. Sixty-four ambulatory, non-depressed, non-demented veterans greater than 74 years of age were interviewed and educated. Knowledge of CPR at baseline was variable and most overestimated their survival chances. Most subjects desired routine CPR discussions with physicians. Only 17% had previously discussed their CPR preferences, and none had done so with physicians. Knowledge of CPR increased (P = 0.01) after educational intervention. There was no change in subjects' CPR decisions after education and presentation of current CPR outcome data. In considering five hypothetical scenarios, 9% never wanted CPR, and 17% always wanted CPR. Those who never wanted CPR were more realistic about their suspected survival chance (P = 0.003) and had higher educational levels (P = 0.03) Folstein (P = 0.03) and Geriatric Depression Scale (P = 0.04) scores. With the dependent variable being the number of hypothetical situations in which the patient desired CPR, a regression analysis (adjusted r2 = 0.72) limited significant variables to the patient's current CPR decision, Folstein score, religion, marital status, and previous ICU admissions. This study emphasizes that most elderly male veterans are willing and want to discuss their CPR attitude with physicians and that most have fixed CPR decisions which may be elicited under stable clinical conditions.