Interstitial fibrosis, left ventricular remodeling, and myocardial mechanical behavior in a population-based multiethnic cohort: the Multi-Ethnic Study of Atherosclerosis (MESA) study

Sex-specific differences in risk factors, comorbidities, diagnostic challenges, optimal management, and prognostic outcomes of heart failure with preserved ejection fraction: A comprehensive literature review

Due to hormonal variations, heart failure with preserved ejection fraction (HFpEF) remains prevalent in women and affects almost half of the heart failure (HF) patients. Given the yearly death rate of 10-30% and the unavailability of medications targeting HFpEF, the need arises for a better understanding of the fundamental mechanisms of this syndrome. This comprehensive review explores sex-specific differences in traditional risk factors; female-specific factors that may impact HFpEF development and response to therapy, including variations in hormone levels that may occur pre- and post-menopausal or during pregnancy; and disparities in comorbidities, clinical presentation, and diagnostic challenges. Lastly, the review addresses prognostic outcomes, noting that women with HFpEF have a poor quality of life but a higher survival rate. It also discusses novel biomarkers and precision medicine, emphasizing their potential to improve early detection and personalized treatment.

Association of Lipoprotein(a) Levels With Myocardial Fibrosis in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Lipoprotein(a) (Lp[a]) has been identified as an emerging risk factor for adverse cardiovascular (CV) outcomes, including heart failure. However, the connections among Lp(a), myocardial fibrosis (interstitial and replacement), and cardiac remodeling as pathways to CV diseases remains unclear.

OBJECTIVES

This study investigated the relationship between Lp(a) levels and myocardial fibrosis by cardiac magnetic resonance (CMR) T1 mapping and late gadolinium enhancement, as well as cardiac remodeling by cine CMR, in the MESA (Multi-Ethnic Study of Atherosclerosis) cohort.

METHODS

The study included 2,040 participants with baseline Lp(a) measurements and T1 mapping for interstitial myocardial fibrosis (IMF) evaluation in 2010. Lp(a) was analyzed as a continuous variable (per log unit) and using clinical cutoff values of 30 and 50 mg/dL. Multivariate linear and logistic regression were used to assess the associations of Lp(a) with CMR measures of extracellular volume (ECV fraction [ECV%]), native T1 time, and myocardial scar, as well as parameters of cardiac remodeling, in 2,826 participants.

RESULTS

Higher Lp(a) levels were associated with increased ECV% (per log-unit Lp[a]; β = 0.2%; P = 0.007) and native T1 time (per log-unit Lp[a]; β = 4%; P < 0.001). Similar relationships were observed between elevated Lp(a) levels and a higher risk of clinically significant IMF defined by prognostic thresholds per log-unit Lp(a) of ECV% (OR: 1.20; 95% CI: 1.04-1.43) and native T1 (OR: 1.2; 95% CI: 1.1-1.4) equal to 30% and 955 ms, respectively. Clinically used Lp(a) cutoffs (30 and 50 mg/dL) were associated with greater prevalence of myocardial scar (OR: 1.85; 95% CI: 1.1-3.2 and OR: 1.9; 95% CI: 1.1-3.4, respectively). Finally, higher Lp(a) levels were associated with left atrial enlargement and dysfunction.

CONCLUSIONS

Elevated Lp(a) levels are linked to greater subclinical IMF, increased myocardial scar prevalence, and left atrial remodeling.

The impact of aging on cardiac remodeling in chronic mitral regurgitation

BACKGROUND

Chronic mitral regurgitation (MR) is a volume overload state that causes dilatation of the left sided cardiac chambers. The presence of significant dilatation is considered an indication for mitral valve intervention, however, aging may affect left ventricular (LV) remodeling independently of valvular disease. The objective of this study was to examine age-related changes in cardiac remodeling in a broad population of patients with chronic MR.

METHODS

Consecutive subjects that underwent echocardiography examinations recorded in the echocardiography database of a university-affiliated laboratory were retrieved. Subjects were categorized into none/mild, moderate or severe MR. For purposes of analysis of differences with aging, the population was divided into groups above and below 70 years of age and standard echocardiographic measurements were compared between the groups.

RESULTS

A total of 3492 subjects with at least moderate MR (mean age: 76 years, 52% female) were included in the study and compared to 18,250 subjects with none or mild MR. Older patients had significantly smaller LV end-diastolic diameters and volumes and significantly larger left atrial (LA) volumes when compared to the younger group. LA volume index increased in both age groups as MR severity increased, while LV end-diastolic volume increased with increasing MR only in the younger population.

CONCLUSIONS

Cardiac remodeling in chronic MR is significantly influenced by age. Guideline based recommendations of timing of mitral valve interventions in asymptomatic MR patients, based on assessment of LA and LV remodeling, may need to take age into account.

Electrocardiographic Associations of Cardiac Biomarkers and Cardiac Magnetic Resonance Measures of Fibrosis in the Multiethnic Study of Atherosclerosis (MESA)

Abnormalities in myocardial substrate, including diffuse and replacement fibrosis, increase the risk of cardiovascular disease (CVD). Data are sparse on whether electrocardiogram (ECG) measures, coupled with circulating biomarkers, may aid in identifying cardiac fibrosis. This study aimed to determine whether 12-lead ECG and biomarkers together augment the prediction of cardiac fibrosis in participants who are free of known CVD. This is a cross-sectional analysis in the MESA (Multiethnic Study of Atherosclerosis) study at visit 5 (2010 to 2012), with measurements of biomarkers (cardiac troponin T and growth differentiation factor-15), gadolinium-enhanced cardiac magnetic resonance imaging, and ECG. Logistic regression associations of ECG measures with cardiac magnetic resonance surrogates of fibrosis (highest quartile extracellular volume [interstitial fibrosis] and late gadolinium enhancement [replacement fibrosis]) were adjusted for demographics and risk factors. Using the C-statistic, we evaluated whether adding ECG measures and biomarkers to clinical characteristics improved the prediction of either type of fibrosis. There were 1,170 eligible participants (aged 67.1 ± 8.6 years). Among the ECG measures, QRS duration (odds ratio [OR] 1.41 per 10 ms, 95% confidence interval [CI] 1.10 to 1.81), major ST-T abnormalities (OR 3.03, 95%CI 1.20, 7.65), and abnormal QRS-T angle (OR 6.32, 95%CI 3.00, 13.33) were associated with replacement fibrosis, whereas only abnormal QRS-T angle (OR 3.05, 95%CI,1.69, 5.48) was associated with interstitial fibrosis. ECG markers, in addition to clinical characteristics, improved the prediction of replacement fibrosis (p = 0.002) but not interstitial fibrosis. The addition of cardiac troponin T and growth differentiation factor-15 to the ECG findings did not significantly improve the model discrimination for either type of cardiac fibrosis. In CVD free participants, simple ECG measures are associated with replacement fibrosis and interstitial fibrosis. The addition of these measures improves identification of replacement but not interstitial fibrosis. These findings may help refine the identification of myocardial scar in the general population.

Cardiovascular Interactions of Renin-Angiotensin-Aldosterone System Assessed by Cardiac Magnetic Resonance: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

The effects of the renin-angiotensin-aldosterone system in cardiovascular system have been described based on small studies. The aim of this study was to evaluate the relationship between aldosterone and plasma renin activity (PRA) and cardiovascular structure and function.

METHODS

We studied a random sample of Multi-Ethnic Study of Atherosclerosis participants who had aldosterone and PRA blood assays at 2003-2005 and underwent cardiac magnetic resonance at 2010. Participants taking angiotensin-converting enzyme inhibitors or angiotensin receptor blockers were excluded.

RESULTS

The aldosterone group was composed by 615 participants, mean age 61.6 ± 8.9 years, while the renin group was 580 participants, mean age 61.5 ± 8.8 years and both groups had roughly 50% females. In multivariable analysis, 1 SD increment of log-transformed aldosterone level was associated with 0.07 g/m2 higher left ventricle (LV) mass index (P = 0.04) and 0.11 ml/m2 higher left atrium (LA) minimal volume index (P < 0.01). Additionally, higher log-transformed aldosterone was associated with lower LA maximum strain and LA emptying fraction (P < 0.01). Aldosterone levels were not significantly associated with aortic measures. Log-transformed PRA was associated with lower LV end diastolic volume index (β standardized = 0.08, P = 0.05). PRA levels were not significantly associated with LA and aortic structural or functional differences.

CONCLUSIONS

Higher levels of aldosterone and PRA are associated with concentric LV remodeling changes. Moreover, aldosterone was related to deleterious LA remodeling changes.

Periodontal Disease Associated With Interstitial Myocardial Fibrosis: The Multiethnic Study of Atherosclerosis

Background Periodontitis is a chronic inflammatory disease common among adults. It has been suggested that periodontal disease (PD) may be a contributing risk factor for cardiovascular disease; however, pathways underlying such a relationship require further investigation. Methods and Results A total of 665 men (mean age 68±9 years) and 611 women (mean age 67±9 years) enrolled in the MESA (Multiethnic Study of Atherosclerosis) underwent PD assessment using a 2-item questionnaire at baseline (2000-2002) and had cardiovascular magnetic resonance 10 years later. PD was defined when participants reported either a history of periodontitis or gum disease or lost teeth caused by periodontitis or gum disease. Multivariable linear regression models were constructed to assess the associations of baseline self-reported PD with cardiovascular magnetic resonance-obtained measures of interstitial myocardial fibrosis (IMF), including extracellular volume and native T1 time. Men with a self-reported history of PD had greater extracellular volume percent (ß=0.6%±0.2, P=0.01). This association was independent of age, left ventricular mass, traditional cardiovascular risk factors, and history of myocardial infarction. In a subsequent model, substituting myocardial infarction for coronary artery calcium score, the association of PD with IMF remained significant (ß=0.6%±0.3, P=0.03). In women, a self-reported history of PD was not linked to higher IMF. Importantly, a self-reported history of PD was not found to be associated with myocardial scar independent of sex (odds ratio, 1.01 [95% CI, 0.62-1.65]; P=0.9). Conclusions In a community-based setting, men but not women with a self-reported PD history at baseline were found to be associated with increased measures of IMF. These findings support a plausible link between PD, a proinflammatory condition, and subclinical IMF.

The landscape of aging

Aging is characterized by a progressive deterioration of physiological integrity, leading to impaired functional ability and ultimately increased susceptibility to death. It is a major risk factor for chronic human diseases, including cardiovascular disease, diabetes, neurological degeneration, and cancer. Therefore, the growing emphasis on "healthy aging" raises a series of important questions in life and social sciences. In recent years, there has been unprecedented progress in aging research, particularly the discovery that the rate of aging is at least partly controlled by evolutionarily conserved genetic pathways and biological processes. In an attempt to bring full-fledged understanding to both the aging process and age-associated diseases, we review the descriptive, conceptual, and interventive aspects of the landscape of aging composed of a number of layers at the cellular, tissue, organ, organ system, and organismal levels.

A clinical study on relationship between visualization of cardiac fibroblast activation protein activity by Al18F-NOTA-FAPI-04 positron emission tomography and cardiovascular disease

Objective

FAP plays a vital role in myocardial injury and fibrosis. Although initially used to study imaging of primary and metastatic tumors, the use of FAPI tracers has recently been studied in cardiac remodeling after myocardial infarction. The study aimed to investigate the application of FAPI PET/CT imaging in human myocardial fibrosis and its relationship with clinical factors.

Materials and methods

Retrospective analysis of FAPI PET/CT scans of twenty-one oncological patients from 05/2021 to 03/2022 with visual uptake of FAPI in the myocardium were applying the American Heart Association 17-segment model of the left ventricle. The patients’ general data, echocardiography, and laboratory examination results were collected, and the correlation between PET imaging data and the above data was analyzed. Linear regression models, Kendall’s TaU-B test, the Spearman test, and the Mann–Whitney U test were used for the statistical analysis.

Results

21 patients (60.1 ± 9.4 years; 17 men) were evaluated with an overall mean LVEF of 59.3 ± 5.4%. The calcific plaque burden of LAD, LCX, and RCA are 14 (66.7%), 12 (57.1%), and 9 (42.9%). High left ventricular SUVmax correlated with BMI (P < 0.05) and blood glucose level (P < 0.05), and TBR correlated with age (P < 0.05). A strong correlation was demonstrated between SUVmean and CTnImax (r = 0.711, P < 0.01). Negative correlation of SUVmean and LVEF (r = −0.61, P < 0.01), SUVmax and LVEF (r = −0.65, P < 0.01) were found. ROC curve for predicting calcified plaques by myocardial FAPI uptake (SUVmean) in LAD, LCX, and RCA territory showed AUCs were 0.786, 0.759, and 0.769.

Conclusion

FAPI PET/CT scans might be used as a new potential method to evaluate cardiac fibrosis to help patients’ management further. FAPI PET imaging can reflect the process of myocardial fibrosis. High FAPI uptakes correlate with cardiovascular risk factors and the distribution of coronary plaques.

Epigenetic remodeling in heart failure with preserved ejection fraction

PURPOSE OF REVIEW

In this review, we critically address the role of epigenetic processing and its therapeutic modulation in heart failure with preserved ejection fraction (HFpEF).

RECENT FINDINGS

HFpEF associates with a poor prognosis and the identification of novel molecular targets and therapeutic approaches are in high demand. Emerging evidence indicates a key involvement of epigenetic signals in the regulation of transcriptional programs underpinning features of HFpEF. The growing understanding of chromatin dynamics has led to the development of selective epigenetic drugs able to reset transcriptional changes thus delaying or preventing the progression toward HFpEF. Epigenetic information in the setting of HFpEF can be employed to: (i) dissect novel epigenetic networks and chromatin marks contributing to HFpEF; (ii) unveil circulating and cell-specific epigenetic biomarkers; (iii) build predictive models by using computational epigenetics and deep machine learning; (iv) develop new chromatin modifying drugs for personalized management of HFpEF.

SUMMARY

Acquired epigenetic signatures during the lifetime can contribute to derail molecular pathways involved in HFpEF. A scrutiny investigation of the individual epigenetic landscape will offer opportunities to develop personalized epigenetic biomarkers and therapies to fight HFpEF in the decades to come.

Myocardial fibrosis by T1 mapping magnetic resonance imaging predicts incident cardiovascular events and all-cause mortality: the Multi-Ethnic Study of Atherosclerosis

AIMS

To evaluate whether myocardial fibrosis predicts cardiovascular events (CVEs) and mortality in the Multi-Ethnic Study of Atherosclerosis.

METHODS AND RESULTS

Cardiac magnetic resonance (CMR) T1 mapping with gadolinium administration for assessment of extracellular volume fraction (ECV) was performed in 1326 participants, in whom myocardial scar was assessed by late gadolinium enhancement (LGE). The clinical outcomes were defined as all-cause mortality, atherosclerotic CVEs, and incident heart failure (HF) during an average of 8 years of follow-up after the scan. Participants' mean native T1 time was 971 ms [standard deviation (SD) 45.5], ECV was 27 (SD 2.9), and 117 (8.8%) of them had LGE. At the time of the CMR exam, participant age was 68 years (SD 9) and 48% of them were women. Ideal cut-offs were identified using classification and regression trees accounting for time-to-event outcomes for ECV (30%) and native T1 time (954 ms). Over the follow-up period, 106 participants died, 78 developed CVE, and 23 developed HF. After adjustment for risk factors, ECV >30% was associated with death [hazard ratio (HR): 1.67, P < 0.05], incident CVE (HR: 2.02, P < 0.05), and incident HF (HR: 2.85, P < 0.05). After adjustments, native T1 >954 ms was associated with incident CVE (HR: 2.09, P < 0.05). Myocardial scar by LGE was not predictive of clinical outcomes after adjustments.

CONCLUSION

ECV is an independent prognostic marker of incident HF, atherosclerotic CVEs, and all-cause mortality. ECV, with its ability to characterize both diffuse and focal fibrosis processes, better predicted incident events than regional myocardial abnormalities as visualized by LGE imaging in a large multi-ethnic population.

Association of immune cell subsets with cardiac mechanics in the Multi-Ethnic Study of Atherosclerosis

BackgroundImmunomodulatory therapy may help prevent heart failure (HF). Data on immune cells and myocardial remodeling in older adults with cardiovascular risk factors are limited.MethodsIn the Multi-Ethnic Study of Atherosclerosis cohort, 869 adults had 19 peripheral immune cell subsets measured and underwent cardiac MRI during the baseline exam, of which 321 had assessment of left ventricular global circumferential strain (LV-GCS). We used linear regression with adjustment for demographics, cardiovascular risk factors, and cytomegalovirus serostatus to evaluate the cross-sectional association of immune cell subsets with left ventricular mass index (LVMI) and LV-GCS.ResultsThe average age of the cohort was 61.6 ± 10.0 years and 53% were women. Higher proportions of γ/δ T cells were associated with lower absolute (worse) LV-GCS (-0.105% [95% CI -0.164%, -0.046%] per 1 SD higher proportion of γ/δ T cells, P = 0.0006). This association remained significant after Bonferroni's correction. Higher proportions of classical monocytes were associated with worse absolute LV-GCS (-0.04% [95% CI -0.07%, 0.00%] per 1 SD higher proportion of classical monocytes, P = 0.04). This did not meet significance after Bonferroni's correction. There were no other significant associations with LV-GCS or LVMI.ConclusionPathways associated with γ/δ T cells may be potential targets for immunomodulatory therapy targeted at HF prevention in populations at risk.FundingContracts 75N92020D00001, HHSN268201500003I, N01-HC-95159, 75N92020D00005, N01-HC-95160, 75N92020D00002, N01-HC-95161, 75N92020D00003, N01-HC-95162, 75N92020D00006, N01-HC-95163, 75N92020D00004, N01-HC-95164, 75N92020D00007, N01-HC-95165, N01-HC-95166, N01-HC-95167, N01-HC-95168, and N01-HC-95169 and grant R01 HL98077 from the National Heart, Lung, and Blood Institute/NIH and grants KL2TR001424, UL1-TR-000040, UL1-TR-001079, and UL1-TR-001420 from the National Center for Advancing Translational Sciences/NIH.

Leveraging clinical epigenetics in heart failure with preserved ejection fraction: a call for individualized therapies

Described as the 'single largest unmet need in cardiovascular medicine', heart failure with preserved ejection fraction (HFpEF) remains an untreatable disease currently representing 65% of new heart failure diagnoses. HFpEF is more frequent among women and associates with a poor prognosis and unsustainable healthcare costs. Moreover, the variability in HFpEF phenotypes amplifies complexity and difficulties in the approach. In this perspective, unveiling novel molecular targets is imperative. Epigenetic modifications-defined as changes of DNA, histones, and non-coding RNAs (ncRNAs)-represent a molecular framework through which the environment modulates gene expression. Epigenetic signals acquired over the lifetime lead to chromatin remodelling and affect transcriptional programmes underlying oxidative stress, inflammation, dysmetabolism, and maladaptive left ventricular remodelling, all conditions predisposing to HFpEF. The strong involvement of epigenetic signalling in this setting makes the epigenetic information relevant for diagnostic and therapeutic purposes in patients with HFpEF. The recent advances in high-throughput sequencing, computational epigenetics, and machine learning have enabled the identification of reliable epigenetic biomarkers in cardiovascular patients. Contrary to genetic tools, epigenetic biomarkers mirror the contribution of environmental cues and lifestyle changes and their reversible nature offers a promising opportunity to monitor disease states. The growing understanding of chromatin and ncRNAs biology has led to the development of several Food and Drug Administration approved 'epidrugs' (chromatin modifiers, mimics, anti-miRs) able to prevent transcriptional alterations underpinning left ventricular remodelling and HFpEF. In the present review, we discuss the importance of clinical epigenetics as a new tool to be employed for a personalized management of HFpEF.

Cardiac fibroblast activation detected by Ga-68 FAPI PET imaging as a potential novel biomarker of cardiac injury/remodeling

BACKGROUND

Fibroblast activation protein (FAP) as a specific marker of activated fibroblasts can be visualized by positron emission tomography (PET) using Ga-68-FAP inhibitors (FAPI). Gallium-68-labeled FAPI is increasingly used in the staging of various cancers. In addition, the first cases of theranostic approaches have been reported. In this work, we describe the phenomenon of myocardial FAPI uptake in patients who received a Ga-68 FAPI PET for tumor staging.

METHOD AND RESULTS

Ga-68 FAPI PET examinations for cancer staging were retrospectively analyzed with respect to cardiac tracer uptake. Standardized uptake values (SUV) were correlated to clinical covariates in a univariate regression model. From 09/2018 to 11/2019 N = 32 patients underwent FAPI PET at our institution. Six out of 32 patients (18.8%) demonstrated increased localized myocardial tracer accumulation, with remote FAPI uptake being significantly higher in patients with vs without localized focal myocardial uptake (SUVmax 2.2 ± .6 vs 1.5 ± .4, P < .05 and SUVmean 1.6 ± .4 vs 1.2 ± .3, P < .05, respectively). Univariate regression demonstrated a significant correlation of coronary artery disease (CAD), age and left ventricular ejection fraction (LVEF) with remote SUVmean uptake, the latter with a very strong correlation with remote uptake (R2 = .74, P < .01).

CONCLUSION

Our study indicates an association of CAD, age, and LVEF with FAPI uptake. Further studies are warranted to assess if fibroblast activation can be reliably measured and may be used for risk stratification regarding early detection or progression of CAD and left ventricular remodeling.

Myocardial extracellular volume fraction quantitation using cardiac dual-energy CT with late iodine enhancement in patients with heart failure without coronary artery disease: A single-center prospective study

PURPOSE

To evaluate the relationship between myocardial extracellular volume (ECV) fraction measured using dual-energy computed tomography with late iodine enhancement (LIE-DECT) and risk of heart failure (HF) in patients without coronary artery disease (CAD), and to evaluate the relationship between ECV and left ventricular structure and function.

MATERIALS AND METHODS

Sixty consecutive HF patients without CAD and 60 consecutive participants without heart disease who underwent coronary CT angiography (CCTA) following LIE-DECT were included. ECV of the left ventricle was calculated from the iodine maps and hematocrit levels using the American Heart Association (AHA) 16-segment model. Cardiac structural and functional parameters were collected including left ventricular end-systolic volume (LVESV), left ventricular end-diastolic volume (LVEDV), left ventricular ejection fraction (LVEF), left atrial volume (LAV), interventricular septal thickness (IVST), and N-terminal pro-brain natriuretic peptide (NT-pro-BNP).

RESULTS

ECV in HF patients without CAD (31.3 ± 4.0 %) was significantly higher than that in healthy subjects (27.1 ± 3.7 %) (P < 0.001). Multivariate linear analysis revealed that ECV was associated with age (β = 0.098, P = 0.010) and hypertension (β = 2.093, P = 0.011) in all participants. Binary logistic regression analysis showed that after adjusting for age, sex, body mass index (BMI), smoking, and drinking, ECV was a risk factor affecting the occurrence of HF in those without CAD (OR = 1.356, 95 %CI：1.178-1.561, P < 0.001). A positive correlation was found between ECV and NT-pro-BNP, LVEDV, LVESV, and LAV (r = 0.629, 0.329, 0.346, and 0.338, respectively; all P < 0.001) in all participants.

CONCLUSIONS

ECV could be measured using LIE-DECT iodine maps. ECV elevation was a risk factor for HF without CAD and correlated with cardiac structure and function.

Extracellular Volume in Primary Mitral Regurgitation

OBJECTIVES

This study used cardiovascular magnetic resonance (CMR) to evaluate whether elevated extracellular volume (ECV) was associated with mitral valve prolapse (MVP) or if elevated ECV was a consequence of remodeling independent of primary mitral regurgitation (MR) etiology.

BACKGROUND

Replacement fibrosis in primary MR is more prevalent in MVP; however, data on ECV as a surrogate for diffuse interstitial fibrosis in primary MR are limited.

METHODS

Patients with chronic primary MR underwent comprehensive CMR phenotyping and were stratified into an MVP cohort (>2 mm leaflet displacement on a 3-chamber cine CMR) and a non-MVP cohort. Factors associated with ECV and replacement fibrosis were assessed. The association of ECV and symptoms related to MR and clinical events (mitral surgery and cardiovascular death) was ascertained.

RESULTS

A total of 424 patients with primary MR (229 with MVP and 195 non-MVP) were enrolled. Replacement fibrosis was more prevalent in the MVP cohort (34.1% vs. 6.7%; p < 0.001), with bi-leaflet MVP having the strongest association with replacement fibrosis (odds ratio: 10.5; p < 0.001). ECV increased with MR severity in a similar fashion for both MVP and non-MVP cohorts and was associated with MR severity but not MVP on multivariable analysis. Elevated ECV was independently associated with symptoms related to MR and clinical events.

CONCLUSIONS

Although replacement fibrosis was more prevalent in MVP, diffuse interstitial fibrosis as inferred by ECV was associated with MR severity, regardless of primary MR etiology. ECV was independently associated with symptoms related to MR and clinical events. (DeBakey Cardiovascular Magnetic Resonance Study [DEBAKEY-CMR]; NCT04281823).

Sex Differences in Cardiovascular Aging and Heart Failure

PURPOSE OF THE REVIEW

This review summarizes sex-related changes in the heart and vasculature that occur with aging, both in the presence and absence of cardiovascular disease (CVD).

RECENT FINDINGS

In the presence of CVD risk factors and/or overt CVD, sex-specific changes in the number of cardiomyocytes, extent of the myocardial extracellular matrix, and myocellular hypertrophy promote unique patterns of LV remodeling in men and women. In addition, age- and sex-specific vascular stiffening is also well established, driven by changes in endothelial dysfunction, elastin-collagen content, microvascular dysfunction, and neurohormonal signaling. Together, these changes in LV chamber geometry and morphology, coupled with heightened vascular stiffness, appear to drive both age-related increases in systolic function and declines in diastolic function, particularly in postmenopausal women. Accordingly, estrogen has been implicated as a key mediator, given its direct vasodilating properties, association with nitric oxide excretion, and involvement in myocellular Ca2+ handling, mitochondrial energy production, and oxidative stress. The culmination of the abovementioned sex-specific cardiac and vascular changes across the lifespan provides important insight into heart failure development, particularly of the preserved ejection fraction variety, while offering promise for future preventive strategies and therapeutic approaches.

Imaging Interstitial Fibrosis, Left Ventricular Remodeling, and Function in Stage A and B Heart Failure

Myocardial interstitial fibrosis is part of the advanced disease stage of most cardiovascular pathologies. It has been characterized histologically in various disease settings from hypertensive heart disease and diabetic cardiomyopathy to severe aortic stenosis. It is also involved in the process of aging. In cardiovascular medicine, myocardial interstitial fibrosis is associated with several adverse outcomes, especially heart failure (HF) and sudden cardiac death. Until recently, clinical measures of interstitial fibrosis could only be made by invasive myocardial biopsy. The availability of cardiac magnetic resonance (CMR) T1 mapping techniques allows for the indirect measurement of interstitial space characteristics and extracellular volume size, which is closely correlated with collagen content and interstitial infiltration by amyloid and other molecules. There has been significant improvement in the accuracy and reproducibility of T1 acquisition sequences in the last decade; however, the correct use of this technique requires a solid CMR expertise in daily imaging practice. CMR has become the gold standard to assess left ventricular (LV) remodeling and functional features associated with interstitial fibrosis. These features can be detected in the early stages of HF. The main objective of this paper is to review the relevant results of preclinical and clinical observational studies that demonstrate the prognostic impact of interstitial fibrosis assessed by T1 mapping, as well as adverse left ventricular remodeling, as determinants of HF. Therefore, this review focuses on the pathological mechanisms underlying LV remodeling and interstitial fibrosis, in addition to the technical considerations involved in the assessment of interstitial LV fibrosis by CMR. It provides a thorough review of clinical evidence that demonstrates the association of interstitial fibrosis and other-CMR derived LV phenotypes with Stages A and B HF.

Inflammatory responses mediate brain-heart interaction after ischemic stroke in adult mice

Stroke induces cardiac dysfunction which increases post stroke mortality and morbidity particularly in aging population. Here, we investigated the effects of inflammatory responses as underlying mediators of cardiac dysfunction after stroke in adult mice. Adult (eight-to-nine months) male C57BL/6 mice were subjected to photothrombotic stroke. To test whether immunoresponse to stroke leads to cardiac dysfunction, splenectomy was performed with stroke. Immunohistochemistry, flow cytometry, PCR, ELISA and echocardiography were performed. We found marginal cardiac dysfunction at acute phase and significant cardiac dysfunction at chronic phase of stroke as indicated by significant decrease of left ventricular ejection fraction (LVEF) and shortening fraction (LVSF). Stroke significantly increases macrophage infiltration into the heart and increases IL-1β, IL-6, MCP-1, TGF-β and macrophage-associated inflammatory cytokine levels in the heart as well as induces cardiac-fibrosis and hypertrophy. Splenectomy with stroke significantly reduces macrophage infiltration into heart, decreases inflammatory factor expression in the heart, decreases cardiac hypertrophy and fibrosis, as well as significantly improves cardiac function compared to non-splenectomized adult stroke mice. Therefore, cerebral ischemic stroke in adult mice induces chronic cardiac dysfunction and secondary immune response may contribute to post stroke cardiac dysfunction.

Differential Gender-Dependent Patterns of Cardiac Fibrosis and Fibroblast Phenotypes in Aging Mice

Aging is characterized by physiological changes within the heart leading to fibrosis and dysfunction even in individuals without underlying pathologies. Gender has been shown to influence the characteristics of cardiac aging; however, gender-dependent cardiac fibrosis occurring with age remains largely not elucidated. Thus, broadening our understanding of this phenomenon proves necessary in order to develop novel anti-fibrotic strategies in the elderly. In this study, we aim to characterize cardiac fibrosis and cardiac fibroblast (CF) populations in aged male and female mice. Echocardiography revealed eccentric hypertrophy with left ventricular dilatation in the aged male versus concentric hypertrophy with left posterior wall thickening in the female, with preserved cardiac function in both groups. Reactive fibrosis was evidenced in the myocardium and epicardium of the aged female mice hearts whereas perivascular and replacement ones where present in the male heart. Collagen I was predominant in the aged male heart whereas collagen III was the main component in the female heart. CFs in the aged male heart were mainly recruited from resident PDGFRα⁺ populations but not derived from epicardium as evidenced by the absence of epicardial progenitor transcription factors Tcf21, Tbx18 and Wt1. Our results present a paradigm for gender-dependent cardiac fibrosis and the origins of CFs with age. This sets forth to revisit cardiac anti-fibrotic management according to the gender in the elderly and to explore novel therapeutic targets.

Sex Differences in the Association of Cumulative Body Mass Index from Early Adulthood to Middle Age and Left Atrial Remodeling Evaluated by Three-Dimensional Echocardiography: The Coronary Artery Risk Development in Young Adults Study

Background:

The relationship between long-term obesity and left atrial (LA) structure and function is not entirely understood. We examined the association of cumulative body mass index (cBMI) with LA remodeling using three-dimensional (3D) speckle-tracking echocardiography (STE).

Methods:

The Coronary Artery Risk Development in Young Adults (CARDIA) study is a community-based cohort of black and white, men and women, ages 18–30 years at baseline in 1985–86 from four U.S. centers. This study included 2,144 participants who had satisfactory image quality and body mass index measurements during the entire follow-up period. The 3D STE-derived LA parameters were maximum, minimum, and pretrial contraction volumes; total, passive, and active emptying fraction; maximum systolic longitudinal strain; and early and late diastolic longitudinal strain rates. Multivariable linear regression analyses stratified by sex assessed the relationship between cBMI and 3D STE-derived LA parameters, adjusting for demographics and traditional cardiovascular.

Results:

The mean age of the cohort was 55 ± 3.6 years; 54.8% were women, and 46.5% were black. There were statistically significant additive sex interactions for the association between cBMI and LA minimum contraction value, maximum systolic longitudinal strain, and early and late diastolic longitudinal strain rates. In the fully adjusted model, greater cBMI was associated with lower magnitude LA longitudinal deformation (maximum systolic longitudinal strain and early and late diastolic longitudinal strain rates) in men and with higher LA emptying fraction in women. In addition, greater cBMI was associated with higher LA phasic volumes indices in both men and women.

Conclusions:

This study showed that while greater cBMI from early adulthood throughout middle age was associated with higher LA volumes in both genders, differences were found for LA function, with lower longitudinal deformation in men and higher reservoir and active LA function in women. (J Am Soc Echocardiogr 2020;33:878–87.)

CD133+Exosome Treatment Improves Cardiac Function after Stroke in Type 2 Diabetic Mice

Cardiac complications post-stroke are common, and diabetes exacerbates post-stroke cardiac injury. In this study, we tested whether treatment with exosomes harvested from human umbilical cord blood derived CD133+ cells (CD133+Exo) improves cardiac function in type 2 diabetes mellitus (T2DM) stroke mice. Adult (3-4 m), male, BKS.Cg-m+/+Lepr^db/J (db/db, T2DM) and non-DM (db+) mice were randomized to sham or photothrombotic stroke groups. T2DM-stroke mice were treated with phosphate-buffered saline (PBS) or CD133+Exo (20 μg, i.v.) at 3 days after stroke. T2DM sham and T2DM+CD133+Exo treatment groups were included as controls. Echocardiography was performed, and mice were sacrificed at 28 days after stroke. Cardiomyocyte hypertrophy, myocardial capillary density, interstitial fibrosis, and inflammatory factor expression were measured in the heart. MicroRNA-126 expression and its target gene expression were measured in the heart. T2DM mice exhibit significant cardiac deficits such as decreased left ventricular ejection fraction (LVEF) and shortening fraction (LVSF), increased left ventricular diastolic dimension (LVDD), and reduced heart rate compared to non-DM mice. Stroke in non-DM and T2DM mice significantly decreases LVEF compared to non-DM and T2DM-sham, respectively. Cardiac dysfunction is worse in T2DM-stroke mice compared to non-DM-stroke mice. CD133+Exo treatment of T2DM-stroke mice significantly improves cardiac function identified by increased LVEF and decreased LVDD compared to PBS treated T2DM-stroke mice. In addition, CD133+Exo treatment significantly decreases body weight and blood glucose but does not decrease lesion volume in T2DM-stroke mice. CD133+Exo treatment of T2DM mice significantly decreases body weight and blood glucose but does not improve cardiac function. CD133+Exo treatment in T2DM-stroke mice significantly decreases myocardial cross-sectional area, interstitial fibrosis, transforming growth factor beta (TGF-β), numbers of M1 macrophages, and oxidative stress markers 4-HNE (4-hydroxynonenal) and NADPH oxidase 2 (NOX2) in heart tissue. CD133+Exo treatment increases myocardial capillary density in T2DM-stroke mice as well as upregulates endothelial cell capillary tube formation in vitro. MiR-126 is highly expressed in CD133+Exo compared to exosomes derived from endothelial cells. Compared to PBS treatment, CD133+Exo treatment significantly increases miR-126 expression in the heart and decreases its target gene expression such as Sprouty-related, EVH1 domain-containing protein 1 (Spred-1), vascular cell adhesion protein (VCAM), and monocyte chemoattractant protein 1 (MCP1) in the heart of T2DM-stroke mice. CD133+Exo treatment significantly improves cardiac function in T2DM-stroke mice. The cardio-protective effects of CD133+Exo in T2DM-stroke mice may be attributed at least in part to increasing miR-126 expression and decreasing its target protein expression in the heart, increased myocardial capillary density and decreased cardiac inflammatory factor expression.

CMR based measurement of aortic stiffness, epicardial fat, left ventricular myocardial strain and fibrosis in hypertensive patients

Introduction

A combined assessment of different parameters of cardiovascular (CV) risk and prognosis can be supportive and performed with cardiac magnetic resonance (CMR). Aortic stiffness, epicardial fat volume (EFV), left ventricular (LV) strain and fibrosis were evaluated within a single CMR examination and results were related to the presence of hypertension (HTN) and diabetes mellitus (DM).

Methods

20 healthy controls (57.2 ± 8.2 years(y); 26.2 ± 3.9 kg/m²), 31 hypertensive patients without DM (59.6 ± 6.7 y; 28.4 ± 4.7 kg/m²) and 12 hypertensive patients with DM (58.8 ± 9.9y; 30.7 ± 6.3 kg/m²) were examined at 1.5Tesla. Aortic stiffness was evaluated by calculation of aortic pulse wave velocity (PWV), EFV by a 3D-Dixon sequence. Longitudinal & circumferential systolic myocardial strain (LS; CS) were analyzed and T1-relaxation times (T1) were determined to detect myocardial fibrosis.

Results

EFV was highest in hypertensive patients with diabetes (78.4 ± 28.0 ml/m²) followed by only hypertensive patients (64.2 ± 27.3 ml/m²) and lowest in controls (50.3 ± 22.7 ml/m²; p < 0.05). PWV was higher in hypertensive patients with diabetes (9.8 ± 3.3 m/s) compared to only hypertensive patients (8.6 ± 1.7 m/s; p < 0.05) and to controls (8.1 ± 1.9 m/s; p < 0.05). LS&CS were worse in hypertensive patients with diabetes (LS:-20.9 ± 5.1% and CS: -24.4 ± 5.7%) compared to both only hypertensive patients (LS: -24.7 ± 4.6%; CS: -27.1 ± 5.0%; p < 0.05) and to controls (LS: -25.5 ± 3.8; CS: -28.3 ± 4.1%; p < 0.05). Both hypertensive groups with and without DM had higher T1́s (994.0 ± 43.2 ms; 991.6 ± 35.5 ms) than controls (964.6 ± 40.3 ms; p < 0.05).

Conclusion

CMR revealed increased aortic stiffness and EFV in hypertensive patients, which were even higher in the presence of DM. Also signs of LV myocardial fibrosis and a reduced strain were revealed. These parameters support the assessment of CV risk and prognosis. They can accurately be measured with CMR within a single examination when normally different techniques are needed.

Pathophysiology of Hypertensive Heart Disease: Beyond Left Ventricular Hypertrophy

PURPOSE OF REVIEW

Given that the life expectancy and the burden of hypertension are projected to increase over the next decade, hypertensive heart disease (HHD) may be expected to play an even more central role in the pathophysiology of cardiovascular disease (CVD). A broader understanding of the features and underlying mechanisms that constitute HHD therefore is of paramount importance.

RECENT FINDINGS

HHD is a condition that arises as a result of elevated blood pressure and constitutes a key underlying mechanism for cardiovascular morbidity and mortality. Historically, studies investigating HHD have primarily focused on left ventricular (LV) hypertrophy (LVH), but it is increasingly apparent that HHD encompasses a range of target-organ damage beyond LVH, including other cardiovascular structural and functional adaptations that may occur separately or concomitantly. HHD is characterized by micro- and macroscopic myocardial alterations, structural phenotypic adaptations, and functional changes that include cardiac fibrosis, and the remodeling of the atria and ventricles and the arterial system. In this review, we summarize the structural and functional alterations in the cardiac and vascular system that constitute HHD and underscore their underlying pathophysiology.

Native T1 and ECV of Noninfarcted Myocardium and Outcome in Patients With Coronary Artery Disease

BACKGROUND

Coronary artery disease (CAD) remains the major cause of cardiac morbidity and mortality worldwide, despite the advances in treatment with coronary revascularization and modern antiremodeling therapy. Risk stratification in CAD patients is primarily based on left ventricular volumes, ejection fraction (LVEF), risk scores, and the presence and extent of late gadolinium enhancement (LGE). The prognostic role of T1 mapping in noninfarcted myocardium in CAD patients has not yet been determined.

OBJECTIVES

This study sought to examine prognostic significance of native T1 mapping of noninfarcted myocardium in patients with CAD.

METHODS

A prospective, observational, multicenter longitudinal study of consecutive patients undergoing routine cardiac magnetic resonance imaging with T1 mapping and LGE. The primary endpoint was all-cause mortality. Major adverse cardiocerebrovascular events (MACCE) (cardiac mortality, nonfatal acute coronary syndrome, stroke, and appropriate device discharge) are also reported.

RESULTS

A total of 34 deaths and 71 MACCE (n = 665, males n = 424, median age [interquartile range] 57 [22] years; 64%; median follow-up period of 17 [11] months) were observed. Native T1 and extracellular volume were univariate predictors of outcome. Native T1 and LGE were stronger predictors of survival and MACCE compared with extracellular volume, LVEF, cardiac volumes, and clinical scores (p < 0.001). Native T1 of noninfarcted myocardium was the sole independent predictor of all-cause mortality (chi-square = 21.7; p < 0.001), which was accentuated in the absence of LGE or LVEF ≤35%. For MACCE, native T1 and LGE extent were joint independent predictors (chi-square = 25.6; p < 0.001).

CONCLUSIONS

Characterization of noninfarcted myocardium by native T1 is an important predictor of outcome in CAD patients, over and above the traditional risk stratifiers. The current study's results provide a basis for a novel risk stratification model in CAD based on a complementary assessment of noninfarcted myocardium and post-infarction scar, by native T1 mapping and LGE, respectively.

Ambient air pollution and pulmonary vascular volume on computed tomography: the MESA Air Pollution and Lung cohort studies

BACKGROUND

Air pollution alters small pulmonary vessels in animal models. We hypothesised that long-term ambient air pollution exposure would be associated with differences in pulmonary vascular volumes in a population-based study.

METHODS

The Multi-Ethnic Study of Atherosclerosis recruited adults in six US cities. Personalised long-term exposures to ambient black carbon, nitrogen dioxide (NO₂), oxides of nitrogen (NO _x ), particulate matter with a 50% cut-off aerodynamic diameter of <2.5 μm (PM_2.5) and ozone were estimated using spatiotemporal models. In 2010-2012, total pulmonary vascular volume was measured as the volume of detectable pulmonary arteries and veins, including vessel walls and luminal blood volume, on noncontrast chest computed tomography (TPVV_CT). Peripheral TPVV_CT was limited to the peripheral 2 cm to isolate smaller vessels. Linear regression adjusted for demographics, anthropometrics, smoking, second-hand smoke, renal function and scanner manufacturer.

RESULTS

The mean±sd age of the 3023 participants was 69.3±9.3 years; 46% were never-smokers. Mean exposures were 0.80 μg·m^-3 black carbon, 14.6 ppb NO₂ and 11.0 μg·m^-3 ambient PM_2.5. Mean±sd peripheral TPVV_CT was 79.2±18.2 cm³ and TPVV_CT was 129.3±35.1 cm³. Greater black carbon exposure was associated with a larger peripheral TPVV_CT, including after adjustment for city (mean difference 0.41 (95% CI 0.03-0.79) cm³ per interquartile range; p=0.036). Associations for peripheral TPVV_CT with NO₂ were similar but nonsignificant after city adjustment, while those for PM_2.5 were of similar magnitude but nonsignificant after full adjustment. There were no associations for NO _x or ozone, or between any pollutant and TPVV_CT.

CONCLUSIONS

Long-term black carbon exposure was associated with a larger peripheral TPVV_CT, suggesting diesel exhaust may contribute to remodelling of small pulmonary vessels in the general population.

Association of myocardial fibrosis and cardiovascular events: the multi-ethnic study of atherosclerosis

Aims

We used contrast-enhanced cardiac magnetic resonance (CMR) to evaluate differences in myocardial fibrosis measured at the year-10 examination between participants with and without cardiovascular (CV) events accrued in a large population based study over the preceding 10-year follow-up period in this retrospective study.

Methods and results

The MESA study enrolled 6814 participants free of CV disease at baseline (2000-2002). We included MESA participants who underwent contrast-enhanced CMR at the MESA year-10 exam (N = 1840). We defined a composite CV endpoint of coronary heart disease, heart failure, atrial fibrillation, stroke, and peripheral artery disease. Using CMR, we characterized myocardial fibrosis with late-gadolinium enhancement for scar and T1 mapping indices of diffuse fibrosis. Demographic and CV-risk adjusted logistic (presence of scar) and linear regression (pre-contrast T1, T1 at 12 and 25 min post-contrast, and extracellular volume fraction or ECV) models were used to assess the relationship between fibrosis and events. The mean values of T1 indices were-pre-contrast T1: 977 ± 45 ms; T1 at 12': 456 ± 40 ms; T1 at 25': 519 ± 41 ms; ECV: 27.1 ± 3.2%. One-hundred and forty-six (7.9%) participants had myocardial scar. The presence of scar was strongly associated with prior CV events (adjusted coeff: 1.36, P < 0.001). Lower post-contrast T1 times and higher ECV, indicative of greater diffuse fibrosis were strongly associated with CV events (T1 at 12': coeff = -10.0 ms, P = 0.004; T1 at 25': coeff =-9.2 ms, P = 0.008; ECV: coeff = 1.31%, P < 0.001).

Conclusion

Individuals who suffered prior CV events have greater likelihood of diffuse myocardial fibrosis when compared with event-free individuals living in the same community.

Association Between Inflammatory Markers and Myocardial Fibrosis

Inflammation promotes adverse ventricular remodeling. T1 mapping has been used to noninvasively assess interstitial myocardial fibrosis. We examined the association of baseline markers of systemic inflammation with interstitial myocardial fibrosis measured by extracellular volume fraction (ECV) and native T1 mapping at 10-year follow-up in the MESA (Multi-Ethnic Study of Atherosclerosis). Seven hundred seventy-two participants had complete baseline data and underwent cardiac magnetic resonance imaging. All analyses were stratified by sex. Multivariable linear regression models were constructed to assess the associations of baseline CRP (C-reactive protein), IL (interleukin)-6, and fibrinogen with native T1 time and ECV. Longer native T1 times and higher percentages of ECV represent increasing myocardial fibrosis. A 1-SD increment of log-transformed IL-6 levels was associated with 0.4% higher ECV in men (β=0.4; P=0.05). CRP and fibrinogen were not associated to ECV. A 1-SD increment in the log-transformed CRP levels was associated with 4.9 ms higher native T1 (β=4.9; P=0.03). In women, the inflammatory markers did not demonstrate association with native T1 nor ECV. Higher IL-6 and CRP levels are associated with increased interstitial myocardial fibrosis assessed by cardiac magnetic resonance in men. However, no inflammatory markers were associated to myocardial fibrosis in women.

CXCR4 Antagonism Reduces Cardiac Fibrosis and Improves Cardiac Performance in Dilated Cardiomyopathy

Background: Myocardial fibrosis is a key pathologic finding in the failing heart and is implicated as a cause of increased ventricular stiffness and susceptibility to ventricular arrhythmia. Neurohormonal mediators such as aldosterone and angiotensin II are known to cause fibrosis in experimental models, however, clinical evidence for the reversal of fibrosis with relevant antagonists is limited. Recent studies suggest that inflammatory mediators may contribute to fibrosis. In dilated cardiomyopathy the mechanism for myocardial fibrosis is unclear and its implications on systolic function are not known. Methods and Results: We studied the effect of a highly selective antagonist of SDF-1/CXCR4 signaling, AMD3100, on the development of cardiac fibrosis and cardiac function in mice with dilated cardiomyopathy due to cardiac-specific transgenic overexpression of the stress-kinase, Mst1. AMD3100 significantly attenuated the progression of myocardial fibrosis and this was accompanied by significant improvements in diastolic and systolic performance as evaluated in isolated Langendorff perfused hearts. AMD3100 reduced BNP mRNA expression but did not alter the expression of Ca²⁺ handling genes. CXCR4 antagonism also reduced the abundance of splenic CD4⁺ T cells. Conclusion: This study demonstrates that CXCR4 pathway contributes to pathogenesis of cardiac fibrosis in dilated cardiomyopathy, and it represents a new potential therapeutic target in heart failure. The data also demonstrate that anti-fibrotic strategies can improve systolic performance.

Systemic Complications of Acromegaly and the Impact of the Current Treatment Landscape: An Update

Acromegaly is a chronic systemic disease with many complications and is associated with increased mortality when not adequately treated. Substantial advances in acromegaly treatment, as well as in the treatment of many of its complications, mainly diabetes mellitus, heart failure, and arterial hypertension, were achieved in the last decades. These developments allowed change in both prevalence and severity of some acromegaly complications and furthermore resulted in a reduction of mortality. Currently, mortality seems to be similar to the general population in adequately treated patients with acromegaly. In this review, we update the knowledge in complications of acromegaly and detail the effects of different acromegaly treatment options on these complications. Incidence of mortality, its correlation with GH (cumulative exposure vs last value), and IGF-I levels and the shift in the main cause of mortality in patients with acromegaly are also addressed.

Mechanisms of Sex Disparities in Cardiovascular Function and Remodeling

Epidemiological studies demonstrate disparities between men and women in cardiovascular disease prevalence, clinical symptoms, treatments, and outcomes. Enrollment of women in clinical trials is lower than men, and experimental studies investigating molecular mechanisms and efficacy of certain therapeutics in cardiovascular disease have been primarily conducted in male animals. These practices bias data interpretation and limit the implication of research findings in female clinical populations. This review will focus on the biological origins of sex differences in cardiovascular physiology, health, and disease, with an emphasis on the sex hormones, estrogen and testosterone. First, we will briefly discuss epidemiological evidence of sex disparities in cardiovascular disease prevalence and clinical manifestation. Second, we will describe studies suggesting sexual dimorphism in normal cardiovascular function from fetal life to older age. Third, we will summarize and critically discuss the current literature regarding the molecular mechanisms underlying the effects of estrogens and androgens on cardiac and vascular physiology and the contribution of these hormones to sex differences in cardiovascular disease. Fourth, we will present cardiovascular disease risk factors that are positively associated with the female sex, and thus, contributing to increased cardiovascular risk in women. We conclude that inclusion of both men and women in the investigation of the role of estrogens and androgens in cardiovascular physiology will advance our understanding of the mechanisms underlying sex differences in cardiovascular disease. In addition, investigating the role of sex-specific factors in the development of cardiovascular disease will reduce sex and gender disparities in the treatment and diagnosis of cardiovascular disease. © 2019 American Physiological Society. Compr Physiol 9:375-411, 2019.

Therapeutic Effects of Wenxin Keli in Cardiovascular Diseases: An Experimental and Mechanism Overview

Cardiovascular diseases (CVDs) are the major public health problem and a leading cause of morbidity and mortality on a global basis. Wenxin Keli (WXKL), a formally classical Chinese patent medicine with obvious efficacy and favorable safety, plays a great role in the management of patients with CVDs. Accumulating evidence from various animal and cell studies has showed that WXKL could protect myocardium and anti-arrhythmia against CVDs. WXKL exhibited its cardioprotective roles by inhibiting inflammatory reaction, decreasing oxidative stress, regulating vasomotor disorders, lowering cell apoptosis, and protection against endothelial injure, myocardial ischemia, cardiac fibrosis, and cardiac hypertrophy. Besides, WXKL could effectively shorten the QRS and Q-T intervals, decrease the incidence of atrial/ventricular fibrillation and the number of ventricular tachycardia episodes, improve the severity of arrhythmias by regulating various ion channels with different potencies, mainly comprising peak sodium current (INa), late sodium current (INaL), transient outward potassium current (Ito), L-type calcium current (ICaL), and pacemaker current (If).

MicroRNA‑20b‑5p promotes ventricular remodeling by targeting the TGF‑β/Smad signaling pathway in a rat model of ischemia‑reperfusion injury

Myocardial ischemic injury results from severe impairment of the coronary blood supply and may lead to metabolic and ultrastructural changes, thereby causing irreversible damage. MicroRNA (miR)-20b-5p has been demonstrated to be involved in malignancies of the breast, colorectum, stomach, blood and oropharynx. The present study aimed to investigate the effects of miR-20b-5p on ventricular remodeling following myocardial ischemia-reperfusion (IR) injury in rats by targeting small mothers against decapentaplegic homolog 7 (Smad7) via the transforming growth factor-β (TGF-β)/Smad signaling pathway. A total of 70 adult male Sprague-Dawley rats were divided into seven groups: Sham group, IR group, negative control group, miR-20b-5p mimics group, miR-20b-5p inhibitors group, small interfering RNA (siRNA)-Smad7 group, and miR-20b-5p inhibitors + siRNA-Smad7 group. Dual luciferase reporter gene assays were used to verify the association between miR-20b-5p and Smad7. Myocardial infarction size, myocardial collagen volume fraction and perivascular collagen area were detected separately using triphenyltetrazolium chloride and Masson's staining. The rate of positive expression of Smad7 was detected using immunohistochemistry, and the expression levels of miR-20b-5p, TGF-β1, Smad3 and Smad7 were detected using reverse transcription-quantitative polymerase chain reaction and western blot analyses. The findings revealed that miR-20b-5p inhibited Smad7. Compared with the sham group, the other six groups had increased myocardial infarction size, myocardial collagen, and expression of miR-20b-5p, TGF-β1 and Smad3, and decreased expression of Smad7. Compared with the IR group, the miR-20b-5p mimics group and the siRNA-Smad7 group had increased myocardial infarction size and myocardial collagen, increased expression of TGF-β1 and Smad3, and decreased expression of Smad7. The expression of miR-20b-5p was markedly increased in the miR-20b-5p mimics group, but did not differ significantly from that in the siRNA-Smad7 group. The results demonstrated that miR-20b-5p promoted ventricular remodeling following myocardial IR injury in rats by inhibiting the expression of Smad7 through activating the TGF-β/Smad signaling pathway.

Extracellular volume quantitation using dual-energy CT in patients with heart failure: Comparison with 3T cardiac MR

BACKGROUNDS

Cardiac magnetic resonance (CMR) T1 mapping and the extracellular volume (ECV) have been developed to quantitative analysis of diffusely abnormal myocardial fibrosis (MF). However, dual-energy CT (DECT) has a potential for calculation of ECV. The aim of this study is to evaluate the feasibility and accuracy of DECT technique in determining the ECV in patients with heart failure, with 3T CMR as the reference.

METHODS

Thirty-five patients with various reasons of heart failure were enrolled in this study. Both DECT and CMR exams were completed within 24 h. ECVs were calculated, and the relationship between DECT-ECV, CMR-ECV, and other heart function parameters, including left ventricular end systolic and diastolic volume, cardiac output and ejection fraction (LVESV, LVEDV, CO, LVEF), Brain natriuretic peptide (BNP) was determined. All participants gave informed consent, and the study was approved by the institutional review board.

RESULTS

The median ECVs on DECT and CMR were 33% (95%CI: 32%-36%) and 30% (95%CI: 30% - 32%), respectively. A good correlation between myocardial ECV at DECT and that at CMR (r = 0.945, P < 0.001) was observed. Bland-Altman analysis between DECT and CMR showed a small bias (2.6%), with 95% limits of agreement of -0.4% and 5.6%. Interobserver agreement for ECV at DECT was excellent (ICC = 0.907). Both ECVs, for DECT and CMR, were inversely associated with LVEF and CO.

CONCLUSION

DECT-based ECV could be an alternative non-invasive imaging tool for myocardial tissue characterization. However, overestimation of the extent of diffuse MF is observed with use of DECT.

Metabolic Syndrome Is Associated With Impaired Diastolic Function Independently of MRI-Derived Myocardial Extracellular Volume: The MESA Study

The relationship of metabolic syndrome (MetS) and insulin resistance (one of its key pathophysiological mediators) with diastolic dysfunction and myocardial fibrosis is not well understood. This study aimed to evaluate the association of MetS with diastolic function and myocardial extracellular matrix (ECM) using cardiac MRI (CMRI) in a large community-based population. This cross-sectional analysis included 1,582 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) with left ventricular ejection fraction ≥50% and no history of cardiac events. Diastolic function was assessed using tagged CMRI parameters including end-diastolic strain rate (EDSR) and strain relaxation index (SRI). ECM was evaluated using extracellular volume (ECV) quantification. Participants' mean age was 67.4 ± 8.6 years, and 48.1% were males. MetS was present in 533 individuals (33.7%), and type 2 diabetes in 250 (15.8%). In the multivariable analyses, MetS (irrespective of the presence of type 2 diabetes) and higher insulin resistance were associated with impaired diastolic function (higher SRI and lower EDSR), independent of ECV. In conclusion, MetS, irrespective of the presence of type 2 diabetes, was independently associated with impaired diastole. These functional myocardial changes seem to result from intrinsic cardiomyocyte alterations, irrespective of the myocardial interstitium (including fibrosis).

Association of Liver Fibrosis With Cardiovascular Diseases in the General Population: The Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

The association of cardiovascular diseases (CVD) with liver fibrosis is poorly understood. We aim to assess the association of liver fibrosis by T1-mapping magnetic resonance imaging and CVD in MESA (Multi-Ethnic Study of Atherosclerosis).

METHODS AND RESULTS

MESA enrolled 6814 participants free of clinical CVD at baseline (2000-2002). A subsample of participants underwent T1-mapping magnetic resonance imaging 10 years after the baseline (Y10 MESA exam, 2010-2012). Liver T1 maps were generated avoiding vessels and biliary ducts from which native T1 (n=2087) and extracellular volume fraction (ECV, n=1234) were determined. Higher ECV and native T1 were indicators of liver fibrosis. Linear regression analysis evaluated the cross-sectional relationship between liver native T1 and ECV at Y10 MESA exam with a history of CVD events (atrial fibrillation, heart failure, and coronary heart disease [CHD]). Of the 2087 participants (68.7±9.1 years; 46% females), 153 had prior CVD events (78 atrial fibrillation, 25 heart failure, and 78 CHD). History of CVD events was associated with 18.5 ms higher liver native T1 (P<0.001) and 1.4% greater ECV (P=0.06). Prior atrial fibrillation was related to higher liver native T1 (β=21.1; P=0.001) and greater ECV (β=2.2; P=0.02), whereas previous heart failure was associated with greater liver ECV (β=4.1; P=0.02). There was also a relationship of prior CHD with liver native T1 (β=13; P=0.05) and ECV (β=1.9; P=0.05), which was attenuated by adjustment for coronary artery calcium score (β=7.1 and 1.6; P=0.37 and 0.13, respectively).

CONCLUSIONS

Liver fibrosis by T1-mapping magnetic resonance imaging is associated with history of heart failure, atrial fibrillation, and CHD in a multiethnic cohort. The association of liver fibrosis and CHD is at least in part mediated by atherosclerosis.

SS31 therapy effectively protects the heart against transverse aortic constriction-induced hypertrophic cardiomyopathy damage

This study tested the hypothesis that SS31 therapy could effectively protect the heart against transverse aortic constriction (TAC)-induced hypertrophic cardiomyopathy (HCM) damage. Adult-male B6 mice (n=36) were equally divided into sham-operated control (group 1), TAC only (group 2) and TAC+SS31 (group) (2.0 mg/kg/day by intra-peritoneal administration from day 28 after TAC induction) and euthanized by day 60. In vitro results showed that SS31 markedly suppressed angiotensin-II induced protein expressions of BNP/β-MHC, ATM, p-P38 and P53 and ATP damage in H9C2 cells, and protein expression of pro-collagen-I/CTGF in fibroblasts (all P<0.001). By day 60, left ventricular ejection fraction (LVEF) and sarcomere length were significantly lower in group 2 than groups 1 and 3, and significantly lower in group 3 than in group 1, whereas the LEVDd/LVESd and ratio of heart weight to tibial length showed an opposite pattern to LVEF (all P<0.0001). Microscopic findings of numbers of apoptotic nuclei, inflammatory (CD14+, F4/80+) and oxidative-stress (H2DCFDA+) biomarkers, disorganized score of endocardium, and fibrotic and collagen-deposition areas showed an opposite pattern to LVEF among the three groups (all P<0.0001). The protein expressions of inflammatory (PDGF/TNF-α/NF-κB/COX-2), oxidative-stress (NOX-1/NOX-2/oxidized protein), fibrotic (TGF-β/Smad3) apoptotic (cleaved-caspase-3/cleaved-PARP), pressure/volume overload (BNP/β-MHC), CTGF, mitochondrial-damaged (cytosolic cytochrome-C), p-ERK1/2, p-Akt and PI3K signaling showed an opposite pattern to LVEF among the three groups (all P<0.001). The protein expression of anti-oxidants (HO-1/Nrf2) were significantly progressively increased in groups 1 to 3 (all P<0.001). In conclusion, SS31 therapy effectively protected the heart against TAC-induced damage.

Association between left ventricular mechanics and diffuse myocardial fibrosis in patients with repaired Tetralogy of Fallot: a cross-sectional study

BACKGROUND

Patients with repaired tetralogy of Fallot (TOF) have progressive, adverse biventricular remodeling, leading to abnormal contractile mechanics. Defining the mechanisms underlying this dysfunction, such as diffuse myocardial fibrosis, may provide insights into poor long-term outcomes. We hypothesized that left ventricular (LV) diffuse fibrosis is related to impaired LV mechanics.

METHODS

Patients with TOF were evaluated with cardiac magnetic resonance in which modified Look-Locker (MOLLI) T1-mapping and spiral cine Displacement encoding (DENSE) sequences were acquired at three LV short-axis positions. Linear mixed modeling was used to define the association between regional LV mechanics from DENSE based on regional T1-derived diffuse fibrosis measures, such as extracellular volume fraction (ECV).

RESULTS

Forty patients (26 ± 11 years) were included. LV ECV was generally within normal range (0.24 ± 0.05). For LV mechanics, peak circumferential strains (-15 ± 3%) and dyssynchrony indices (16 ± 8 ms) were moderately impaired, while peak radial strains (29 ± 8%) were generally normal. After adjusting for patient age, sex, and regional LV differences, ECV was associated with log-adjusted LV dyssynchrony index (β = 0.67) and peak LV radial strain (β = -0.36), but not LV circumferential strain. Moreover, post-contrast T1 was associated with log-adjusted LV diastolic circumferential strain rate (β = 0.37).

CONCLUSIONS

We observed several moderate associations between measures of fibrosis and impaired mechanics, particularly the LV dyssynchrony index and peak radial strain. Diffuse fibrosis may therefore be a causal factor in some ventricular dysfunction in TOF.

Cardiac MRI: a Translational Imaging Tool for Characterizing Anthracycline-Induced Myocardial Remodeling

Cardiovascular side effects of cancer therapeutics are the leading causes of morbidity and mortality in cancer survivors. Anthracyclines (AC) serve as the backbone of many anti-cancer treatment strategies, but dose-dependent myocardial injury limits their use. Cumulative AC exposure can disrupt the dynamic equilibrium of the myocardial microarchitecture while repeated injury and repair leads to myocyte loss, interstitial myocardial fibrosis, and impaired contractility. Although children are assumed to have greater myocardial plasticity, AC exposure at a younger age portends worse prognosis. In older patients, there is lower overall survival once they develop cardiovascular disease. Because aberrations in the myocardial architecture predispose the heart to a decline in function, early detection with sensitive imaging tools is crucial and the implications for resource utilization are substantial. As a comprehensive imaging modality, cardiac magnetic resonance (CMR) imaging is able to go beyond quantification of ejection fraction and myocardial deformation to characterize adaptive microstructural and microvascular changes that are important to myocardial tissue health. Herein, we describe CMR as an established translational imaging tool that can be used clinically to characterize AC-associated myocardial remodeling.

Cardiovascular magnetic resonance in an adult human population: serial observations from the multi-ethnic study of atherosclerosis

The Multi-Ethnic Study of Atherosclerosis (MESA) is the first large-scale multi-ethnic population study in the U.S. to use advanced cardiovascular magnetic resonance (CMR) imaging. MESA participants were free of cardiovascular disease at baseline between 2000 and 2002, and were followed up between 2009 and 2011 with repeated CMR examinations as part of MESA. CMR allows the clinician to visualize and accurately quantify volume and dimensions of all four cardiac chambers; measure systolic and diastolic ventricular function; assess myocardial fibrosis; assess vessel lumen size, vessel wall morphology, and vessel stiffness. CMR has a number of advantages over other imaging modalities such as echocardiography, computed tomography, and invasive angiography, and has been proposed as a diagnostic strategy for high-risk populations. MESA has been extensively evaluating CMR imaging biomarkers, as markers of subclinical disease, in the last 15 years for low-risk populations. On a more practical level, some of the imaging biomarkers developed and studied are translatable to at-risk populations. In this review, we discuss the progression of subclinical cardiovascular disease and the mechanisms responsible for the transition to symptomatic clinical outcomes based on our findings from MESA.

Association of Aortic Stiffness With Left Ventricular Remodeling and Reduced Left Ventricular Function Measured by Magnetic Resonance Imaging: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

This study sought to assess cross-sectional associations of aortic stiffness assessed by magnetic resonance imaging with left ventricular (LV) remodeling and myocardial deformation in the Multi-Ethnic Study of Atherosclerosis (MESA).

METHODS AND RESULTS

Aortic arch pulse wave velocity (PWV) was measured with phase contrast cine magnetic resonance imaging. LV circumferential strain (Ecc), torsion, and early diastolic strain rate were determined by tagged magnetic resonance imaging. Multivariable linear regression models were used to adjust for demographics and cardiovascular risk factors. Of 2093 participants, multivariable linear regression models demonstrated that higher arch PWV was associated with higher LV mass index (B=0.53 per 1 SD increase for log-transformed PWV, P<0.05) and LV mass to volume ratio (B=0.015, P<0.01), impaired LV ejection fraction (LVEF; B=-0.84; P<0.001), Ecc (B=0.55; P<0.001), torsion (B=-0.11; P<0.001), and early diastolic strain rate (B=-0.003; P<0.05). In sex stratified analysis, higher arch PWV was associated with higher MVR (B=0.02; P<0.05), impaired Ecc (B=0.60; P<0.001), and LVEF (B=-0.45; P<0.05), but with maintained torsion in women. Higher PWV was associated with impaired Ecc (B=0.49; P<0.001) and LVEF (B=-1.21; P<0.001), with lower torsion (B=-0.17; P<0.001) in men.

CONCLUSIONS

Higher arch PWV is associated with LV remodeling, and reduced LV systolic and diastolic function in a large multiethnic population. Greater aortic arch stiffness is associated with concentric LV remodeling and relatively preserved LVEF with maintained torsion in women, whereas greater aortic arch stiffness is associated with greater LV dysfunction demonstrated as impaired Ecc, torsion, and LVEF, with less concentric LV remodeling in men.

Effects of Wenxin Keli on Cardiac Hypertrophy and Arrhythmia via Regulation of the Calcium/Calmodulin Dependent Kinase II Signaling Pathway

We investigated the effects of Wenxin Keli (WXKL) on the Calcium/Calmodulin dependent kinase II (CaMK II) signal transduction pathway with transverse aortic constriction (TAC) rats. Echocardiographic measurements were obtained 3 and 9 weeks after the surgery. Meanwhile, the action potentials (APDs) were recorded using the whole-cell patch clamp technique, and western blotting was used to assess components of the CaMK II signal transduction pathway. At both 3 and 9 weeks after treatment, the fractional shortening (FS%) increased in the WXKL group compared with the TAC group. The APD90 of the TAC group was longer than that of the Sham group and was markedly shortened by WXKL treatment. Western blotting results showed that the protein expressions of CaMK II, phospholamban (PLB), and ryanodine receptor 2 (RYR2) were not statistically significant among the different groups at both treatment time points. However, WXKL treatment decreased the protein level and phosphorylation of CaMK II (Thr-286) and increased the protein level and phosphorylation of PLB (Thr-17) and the phosphorylation of RYR2 (Ser-2814). WXKL also decreased the accumulation of type III collagen fibers. In conclusion, WXKL may improve cardiac function and inhibit the arrhythmia by regulating the CaMK II signal transduction pathway.

Pulmonary vascular volume, impaired left ventricular filling and dyspnea: The MESA Lung Study

BACKGROUND

Evaluation of impaired left ventricular (LV) filling has focused on intrinsic causes of LV dysfunction; however, pulmonary vascular changes may contribute to reduced LV filling and dyspnea. We hypothesized that lower total pulmonary vascular volume (TPVV) on computed tomography (CT) would be associated with dyspnea and decrements in LV end-diastolic volume, particularly among ever-smokers.

METHODS

The Multi-Ethnic Study of Atherosclerosis recruited adults without clinical cardiovascular disease in 2000-02. In 2010-12, TPVV was ascertained as the volume of arteries and veins in the lungs detectable on non-contrast chest CT (vessels ≥1 mm diameter). Cardiac measures were assessed by magnetic resonance imaging (MRI). Dyspnea was self-reported.

RESULTS

Of 2303 participants, 53% had ever smoked cigarettes. Among ever-smokers, a lower TPVV was associated with a lower LV end-diastolic volume (6.9 mL per SD TPVV), stroke volume, and cardiac output and with dyspnea (all P-values <0.001). Findings were similar among those without lung disease and those with 0-10 pack-years but were mostly non-significant among never-smokers. TPVV was associated smaller left atrial volume but not with LV ejection fraction or MRI measures of impaired LV relaxation. In a second sample of ever-smokers, a lower pulmonary microvascular blood volume on contrast-enhanced MRI was also associated with a lower LV end-diastolic volume (P-value = 0.008).

CONCLUSION

Reductions in pulmonary vascular volume were associated with lower LV filling and dyspnea among ever-smokers, including those without lung disease, suggesting that smoking-related pulmonary vascular changes may contribute to symptoms and impair cardiac filling and function without evidence of impaired LV relaxation.

Hypertrabeculated Left Ventricular Myocardium in Relationship to Myocardial Function and Fibrosis: The Multi-Ethnic Study of Atherosclerosis

Purpose To determine if excess greater left ventricle (LV) trabeculation is associated with decreased average regional myocardial function, diffuse fibrosis, or both. Materials and Methods This was a HIPAA-compliant institutional board approved multicenter study, and all participants provided written informed consent. Participants in the Multi-Ethnic Study of Atherosclerosis (MESA) underwent a comprehensive cardiac magnetic resonance (MR) examination. LV trabeculation was measured with the maximal apical fractal dimension (FD), which is a marker of endocardial complexity. Demographic covariates, cardiovascular risk factors, and cardiac MR measurements were compared across quartiles of FD. Associations between FD and peak regional systolic circumferential strain (Ecc) and T1 time, a surrogate for diffuse myocardial fibrosis, were assessed with multivariable linear regression models. Results A total of 1123 subjects (593 [52.8%] female; mean age, 67.1 years ± 8.7 [standard deviation]) underwent FD and Ecc measurement, and 992 (521 [52.5%] female; mean age, 67.1 years ± 8.7) underwent FD and T1 measurement. Mean FD was 1.2 ± 0.07 in both groups, and mean Ecc was -18.3 ± 2.27 in the subjects who underwent FD and Ecc measurement. Global volumes and ejection fraction showed no differences between FD quartiles. However, with increasing FD quartile, Ecc was greater (indicating worse average regional function) (P < .001). After adjustment, greater trabeculation was associated with 21% worse myocardial strain (relative to the mean) per unit change in FD (regression coefficient = 4.0%; P < .001). There was no association between the degree of trabeculation and diffuse fibrosis measured with T1 mapping. Conclusion Average regional LV function was worse in individuals with greater LV trabeculation, supporting the concept of hypertrabeculation being an epiphenomenon of disease. ^© RSNA, 2017.