Characterization of aging-associated cardiac diastolic dysfunction

Iron accumulation and lipid peroxidation: implication of ferroptosis in diabetic cardiomyopathy

Diabetic cardiomyopathy (DC) is a serious heart disease caused by diabetes. It is unrelated to hypertension and coronary artery disease and can lead to heart insufficiency, heart failure and even death. Currently, the pathogenesis of DC is unclear, and clinical intervention is mainly symptomatic therapy and lacks effective intervention objectives. Iron overdose mediated cell death, also known as ferroptosis, is widely present in the physiological and pathological processes of diabetes and DC. Iron is a key trace element in the human body, regulating the metabolism of glucose and lipids, oxidative stress and inflammation, and other biological processes. Excessive iron accumulation can lead to the imbalance of the antioxidant system in DC and activate and aggravate pathological processes such as excessive autophagy and mitochondrial dysfunction, resulting in a chain reaction and accelerating myocardial and microvascular damage. In-depth understanding of the regulating mechanisms of iron metabolism and ferroptosis in cardiovascular vessels can help improve DC management. Therefore, in this review, we summarize the relationship between ferroptosis and the pathogenesis of DC, as well as potential intervention targets, and discuss and analyze the limitations and future development prospects of these targets.

Late-life Rapamycin Treatment Enhances Cardiomyocyte Relaxation Kinetics and Reduces Myocardial Stiffness

Diastolic dysfunction is a key feature of the aging heart. We have shown that late-life treatment with mTOR inhibitor, rapamycin, reverses age-related diastolic dysfunction in mice but the molecular mechanisms of the reversal remain unclear. To dissect the mechanisms by which rapamycin improves diastolic function in old mice, we examined the effects of rapamycin treatment at the levels of single cardiomyocyte, myofibril and multicellular cardiac muscle. Compared to young cardiomyocytes, isolated cardiomyocytes from old control mice exhibited prolonged time to 90% relaxation (RT 90 ) and time to 90% Ca 2+ transient decay (DT 90 ), indicating slower relaxation kinetics and calcium reuptake with age. Late-life rapamycin treatment for 10 weeks completely normalized RT 90 and partially normalized DT 90 , suggesting improved Ca 2+ handling contributes partially to the rapamycin-induced improved cardiomyocyte relaxation. In addition, rapamycin treatment in old mice enhanced the kinetics of sarcomere shortening and Ca 2+ transient increase in old control cardiomyocytes. Myofibrils from old rapamycin-treated mice displayed increased rate of the fast, exponential decay phase of relaxation compared to old controls. The improved myofibrillar kinetics were accompanied by an increase in MyBP-C phosphorylation at S282 following rapamycin treatment. We also showed that late-life rapamycin treatment normalized the age-related increase in passive stiffness of demembranated cardiac trabeculae through a mechanism independent of titin isoform shift. In summary, our results showed that rapamycin treatment normalizes the age-related impairments in cardiomyocyte relaxation, which works conjointly with reduced myocardial stiffness to reverse age-related diastolic dysfunction.

Development and validation of a nomogram for prediction of the risk of positive hidden blood loss in the perioperative period of single-level thoracolumbar burst fracture

BACKGROUND

This study aimed to develop and validate an individualized nomogram to predict the risk of positive hidden blood loss (HBL) in patients with single-level thoracolumbar burst fracture (TBF) during the perioperative period.

METHODS

We conducted a retrospective investigation including 150 consecutive patients with TBL, and the corresponding patient data was extracted from March 2013 to March 2019. The independent risk factors for positive HBL were screened using univariate and multivariate logistic regression analyses. According to published literature and clinical experience, a series of variables were selected to develop a nomogram prediction model for positive HBL. The area under the receiver operating characteristic curves (AUC), C-index, calibration plot, and decision curve analysis (DCA) were used to evaluate the performance of the prediction model. Bootstrapping validation was performed to evaluate the performance of the model.

RESULTS

Among the 150 consecutive patients, 62 patients were positive for HBL (38.0%). The multivariate logistic regression analysis showed that the six risk factors of age, length of surgical incision, duration of operation, percentage of vertebral height restoration (P1%), preoperative total cholesterol, and preoperative fibrinogen were independent risk factors of positive HBL. The C-index was 0.831 (95% CI 0.740-0.889) and 0.845 in bootstrapping validation, respectively. The calibration curve showed that the predicted probability of the model was consistent with the actual probability. Decision curve analysis (DCA) showed that the nomogram had clinical utility.

CONCLUSION

Overall, we explored the relationship between the positive HBL requirement and predictors. The individualized prediction model for patients with single-level TBF can accurately assess the risk of positive HBL and facilitate clinical decision making. However, external validation will be needed in the future.

Macrophage phenotype and function are dependent upon the composition and biomechanics of the local cardiac tissue microenvironment

Macrophage accumulation and nitrosative stress are known mechanisms underlying age-related cardiovascular pathology and functional decline. The cardiac muscle microenvironment is known to change with age, yet the direct effects of these changes have yet to be studied in-depth. The present study sought to better elucidate the role that biochemical and biomechanical alterations in cardiac tissue have in the altered phenotype and functionality of cardiac resident macrophages observed with increasing age. To accomplish this, naïve bone marrow derived macrophages from young mice were seeded onto either functionalized poly-dimethyl-siloxane hydrogels ranging in stiffness from 2kPA to 64kPA or onto tissue culture plastic, both of which were coated with either young or aged solubilized mouse cardiac extracellular matrix (cECM). Both biomechanical and biochemical alterations were found to have a significant effect on macrophage polarization and function. Increased substrate stiffness was found to promote macrophage morphologies associated with pro-inflammatory macrophage activation, increased expression of pro-inflammatory inducible nitric oxide synthase protein with increased nitric oxide secretion, and attenuated arginase activity and protein expression. Additionally, exposure to aged cECM promoted attenuated responsivity to both canonical pro-inflammatory and anti-inflammatory cytokine signaling cues when compared to young cECM treated cells. These results suggest that both biomechanical and biochemical changes in the cardiovascular system play a role in promoting the age-related shift towards pro-inflammatory macrophage populations associated with cardiovascular disease development.

The association between the renal resistive index and the myocardial performance index in the general population

OBJECTIVE

The renal resistive index (RRI) is the most described measure of renal hemodynamics. The myocardial performance index (MPI) is widely used to assess overall myocardial performance. In this study, we aimed to investigate the relationship between renal hemodynamics, assessed by the RRI, and cardiac functions, assessed by the MPI in the general population.

METHODS

This single-center, cross-sectional study included a total of 302 consecutive patients who presented to our outpatient cardiology clinic between October 2019 and February 2020. All patients underwent transthoracic echocardiography and renal Doppler ultrasonography. The study population was divided into two groups: low RRI group (RRI ≤ 0.7, n = 236) and high RRI group (RRI > 0.7, n = 66).

RESULTS

E/A ratio, left ventricular ejection fraction (LVEF), and the MPI were significantly higher in the high RRI group than in the low RRI group (61.3 ± 15.4 vs 55.3 ± 16.4, P = .010 for E velocity; 0.9 ± 0.3 vs 0.7 ± 0.2, P = .008 for E/A ratio; 57.7 ± 4.7 vs 53.2 ± 10.1, P = .029 for LVEF; 0.52 ± 0.1 vs 0.43 ± 0.1, P < .001 for the MPI). A stepwise linear regression analysis demonstrated that LVEF (β = .123, P = .026), E velocity (β = .221, P < .001), and the MPI (β = .392, P < .001) were independently associated with the RRI.

CONCLUSION

Left ventricular ejection fraction and intra-cardiac Doppler blood flow indices, including E velocity and the MPI, were significantly and independently associated with the RRI in the general population.

Sirtuin 3, Endothelial Metabolic Reprogramming, and Heart Failure With Preserved Ejection Fraction

The incidences of heart failure with preserved ejection fraction (HFpEF) are increased in aged populations as well as diabetes and hypertension. Coronary microvascular dysfunction has contributed to the development of HFpEF. Endothelial cells (ECs) depend on glycolysis rather than oxidative phosphorylation for generating adenosine triphosphate to maintain vascular homeostasis. Glycolytic metabolism has a critical role in the process of angiogenesis, because ECs rely on the energy produced predominantly from glycolysis for migration and proliferation. Sirtuin 3 (SIRT3) is found predominantly in mitochondria and its expression declines progressively with aging, diabetes, obesity, and hypertension. Emerging evidence indicates that endothelial SIRT3 regulates a metabolic switch between glycolysis and mitochondrial respiration. SIRT3 deficiency in EC resulted in a significant decrease in glycolysis, whereas, it exhibited higher mitochondrial respiration and more prominent production of reactive oxygen species. SIRT3 deficiency also displayed striking increases in acetylation of p53, EC apoptosis, and senescence. Impairment of SIRT3-mediated EC metabolism may lead to a disruption of EC/pericyte/cardiomyocyte communications and coronary microvascular rarefaction, which promotes cardiomyocyte hypoxia, Titin-based cardiomyocyte stiffness, and myocardial fibrosis, thus leading to a diastolic dysfunction and HFpEF. This review summarizes current knowledge of SIRT3 in EC metabolic reprograming, EC/pericyte interactions, coronary microvascular dysfunction, and HFpEF.

Prevalence, Characteristics and Risk Factors for Embolic Stroke of Undetermined Source in West and South Asia and North African Population Residing in Qatar

BACKGROUND AND PURPOSE

Embolic stroke of undetermined source (ESUS) is an important contributor to stroke worldwide. Little is known about ESUS in developing parts of the world such as South Asia, West Asia and North Africa despite the high stroke burden in these areas. The purpose of the study was to characterize the prevalence, demographic, risk factor and clinical aspects of ESUS in patients from South Asia, West Asia and North Africa residing in Qatar.

METHODS

Data were retrospectively collected on 3103 stoke patients. Risk factors and clinical features of the ESUS group were compared to all other strokes using Chi-square or student's t-tests. Logistic regression was used to identify factors associated with ESUS. ESUS patients were compared based on ethnicity using Chi-square or one-way ANOVA.

RESULTS

634 patients (30·9%, 95% CI (28·9%-32·9%) met the ESUS criteria. Mean age was 56·3 years ± 13·7 and South Asian ESUS patients were younger than West Asians or North Africans (67·1 ± 13·5 versus 52·1 ± 10·8 versus 53·5 ± 14·2, P = .001). Smoking, diastolic function, prior antiplatelets and wall motion abnormalities were more common in ESUS. Logistic regression showed that South Asian ethnicity (OR 1·50, CI 1·14-1·97, P = ·003), diastolic dysfunction (OR 1·47, CI 1·23-1·75, P = ·005), global (OR 1·79, CI 1·41-2·26, P = ·001) and focal (OR 5·48, CI 3·79-7·92, P = ·001) wall motion abnormalities, predicted ESUS.

CONCLUSIONS

ESUS is a major cause of stroke in patients from West Asia, South Asia and North Africa residing in Qatar. The clinical profile and risk factors for ESUS vary based on ethnicity. In South Asians, ESUS occurs at a younger age and is most likely cardiogenic in origin.

Cardiac Abnormalities in Patients With Hutchinson-Gilford Progeria Syndrome

Importance

Hutchinson-Gilford progeria syndrome (HGPS) is an ultrarare disorder associated with premature death due to cardiovascular events during the second decade of life. However, because of its rarity (107 identified living patients), the natural history of cardiac disease remains uncharacterized. Therefore, meaningful cardiac end points for clinical trials have been difficult to establish.

Objective

To examine the course of appearance of cardiac abnormalities in patients with HGPS to identify meaningful cardiac end points for use in future clinical trials.

Design, Setting, and Participants

In this prospective, cross-sectional, observational study, 27 consecutive patients with clinically and genetically confirmed classic HGPS were evaluated at a single center for 1 visit from July 1, 2014, through February 29, 2016, before initiation of treatment.

Exposure

Classic HGPS.

Main Outcomes and Measures

Echocardiography was used to assess ventricular and valve function using standard techniques. Diastolic left ventricular (LV) function was assessed using tissue Doppler imaging. Previously published normative data were used to adjust findings to age and body size.

Results

This study included 27 patients (median age, 5.6 years; age range, 2-17 years; 15 [56%] male). Among echocardiographic indicators, LV diastolic dysfunction, defined as a tissue Doppler septal or lateral early velocity z score less than -2, was the most prevalent abnormality, seen in 16 patients (59%). Diastolic dysfunction was seen in all age groups, and its prevalence increased with age, mirroring findings seen during normal aging. Indicators of LV diastolic function were more abnormal in older patients. The z scores for lateral and septal early velocities were lower (r = -0.77, P < .001; and r = -0.66, P < .001, respectively), whereas those for the ratio of early mitral inflow velocity to early diastolic tissue Doppler myocardial velocity were higher (r = 0.80, P < .001; and r = 0.72, P < .001, respectively) in older patients. Other echocardiographic findings, including LV hypertrophy, LV systolic dysfunction, and valve disease, were less prevalent in the first decade and were seen more frequently in the second decade.

Conclusions and Relevance

In this largest-to-date cohort of patients with HGPS, LV diastolic dysfunction was the most prevalent echocardiographic abnormality and its prevalence increased with aging. Echocardiographic indicators of LV diastolic function may be useful end points in future clinical trials in this patient population.

Serum vitamin D, intact parathyroid hormone, and Fetuin A concentrations were associated with geriatric sarcopenia and cardiac hypertrophy

With aging, intact parathyroid hormone (iPTH) increases. It plays a crucial role in left ventricular hypertrophy (LVH). Also, 25-hydroxy vitamin D (Vit-D) and iPTH have been observed to be determinants of muscle wasting known as sarcopenia. Fetuin A (FetA), a systemic calcification inhibitor, involves in the development of diastolic heart failure. Hence, we hypothesized that the interplay among FetA, Vit-D and iPTH may contribute to sarcopenic LVH among the elders. We analyzed a database from the Tianliao Old People study with 541 elders (≥65 years) in a Taiwan’s suburban community. After excluding patients with renal function impairment, 120/449 (26.7%) patients were diagnosed with sarcopenia. Sarcopenic patients had lower serum Vit-D levels but higher FetA as well as iPTH. Notably, sarcopenic patients with LVH had significantly lower FetA and higher iPTH levels. In multivariate logistic regression analysis, only the increase in iPTH was independently associated with sarcopenic LVH (Odds ratio: 1.05; confidence interval: 1.03–1.08, p = 0.005). Using iPTH >52.3 ng/l as a cutoff point, the sensitivity and specificity was 66% and 84%, respectively. In conclusion, FetA, Vit-D, and iPTH levels were all associated with sarcopenia in this geriatric population. Among them, iPTH specifically indicates patients with sarcopenic LVH.

Interplay of Aging and Hypertension in Cardiac Remodeling: A Mathematical Geometric Model

Hypertensive disorder can cause cardiac deformities. Elastic characteristic parameters, like Young’s modulus of elasticity (E) derived from a traditional cylindrical model, increase significantly with aging. However, the geometric and component changes of aging hearts because of chronic hypertension remain unknown. To better describe the effects, we propose an elliptical elastic and mathematical model to evaluate myocardial stiffness. Ninety-six hypertensive patients (HTN^Pos) (men: 59.3%; age ≥ 65 years: 20.8%) were enrolled and compared with normotensive controls (HTN^Neg) (n = 47, 48.9%). HTN^Pos patients had a thicker interventricular septum in diastole (IVSd) (HTN^Pos: 0.96 ± 0.21 cm vs. HTN^Neg: 0.77 ± 0.15; p = 0.005) and higher intracardiac pressure (e/e′: 9.06 ± 4.85 cm vs. 7.76 ± 3.41; p = 0.01), especially the elderly (> 65 years) (IVSd: 1.03 ± 0.19 cm, e/e′: 11.39 ± 1.99; p = 0.006 and 0.01, respectively). Nevertheless, the internal dimension decreased more significantly in the HTN^Pos rather than in the HTN^Neg elderly (5.23 ± 0.46 vs. 4.74 ± 0.69 cm; p = 0.02). We found different directions of cardiac remodeling with normotensive and hypertensive loads. Different from the longitudinal and circumferential strain, E and Poisson’s ratio (υ) are values that directly present the rigidity of myocardium. E was significantly higher in the elderly (8011.92 ± 2431.85 vs. 6052.43 ± 3121.50; p = 0.02), whereas υ was significantly higher in all HTN^Pos patients (0.73 ± 0.12 vs. 0.61 ± 0.07; p < 0.001). Because E and υ reflected the material changes of myocardium in the HTN^Pos elderly, the proposed elliptical mathematical heart model better describes the geometric deformity induced by aging and hypertension.

Prognostic value of ventricular diastolic dysfunction in patients with severe sepsis and septic shock

OBJECTIVES

To evaluate the prevalence of myocardial dysfunction and its prognostic value in patients with severe sepsis and septic shock.

METHODS

Adult septic patients admitted to an intensive care unit were prospectively studied using transthoracic echocardiography within the first 48 hours after admission and thereafter on the 7th-10th days. Echocardiographic variables of biventricular function, including the E/e' ratio, were compared between survivors and non-survivors.

RESULTS

A total of 99 echocardiograms (53 at admission and 46 between days 7 - 10) were performed on 53 patients with a mean age of 74 (SD 13) years. Systolic and diastolic dysfunction was present in 14 (26%) and 42 (83%) patients, respectively, and both types of dysfunction were present in 12 (23%) patients. The E/e' ratio, an index of diastolic dysfunction, was the best predictor of hospital mortality according to the area under the ROC curve (0.71) and was an independent predictor of outcome, as determined by multivariate analysis (OR = 1.36 [1.05 - 1.76], p = 0.02).

CONCLUSION

In septic patients admitted to an intensive care unit, echocardiographic systolic dysfunction is not associated with increased mortality. In contrast, diastolic dysfunction is an independent predictor of outcome.

Fetuin-A as a predicator of sarcopenic left ventricular dysfunction

Sarcopenia is an aging condition involving low muscle mass and function. Fetuin-A (FetA) appears to be a factor for body composition remodeling. We hypothesized that age increases FetA levels and deteriorates the myocardial function by affecting diastolic function, especially in people with sarcopenia. We enrolled 541 asymptomatic elderly (≥65 years) patients. Compared with non-sarcopenic population, FetA levels were significantly elevated in the ninety-two (17%) patients (79 ± 6 years; male: 34.7%) diagnosed with sarcopenia (621.1 ± 140.7 vs. 697.3 ± 179.6 μg/ml, < 0.001). Sarcopenic left ventricular dysfunction (S-LVD) was defined by the coexistence of sarcopenia and systolic impairment (LVEF < 50%) and 23 (4.3%) of them met the criteria. Patients with S-LVD showed relatively reduced systolic heart function, higher end-diastolic pressure and a higher FetA level (all p < 0.001) than did those with sarcopenia but without LV dysfunction (S-NLVD). Conversely, in the group without sarcopenia, FetA levels were similar regardless of systolic function. Multivariable logistic regression showed that older age, impaired diastolic function, and higher FetA levels were significantly associated with S-LVD. In conclusion, we found that FetA was significantly higher in elderly patients with sarcopenia, which was associated with impaired diastolic and systolic functions.

Continuing treatment with Salvia miltiorrhiza injection attenuates myocardial fibrosis in chronic iron-overloaded mice

Iron overload cardiomyopathy results from iron accumulation in the myocardium that is closely linked to iron-mediated myocardial fibrosis. Salvia miltiorrhiza (SM, also known as Danshen), a traditional Chinese medicinal herb, has been widely used for hundreds of years to treat cardiovascular diseases. Here, we investigated the effect and potential mechanism of SM on myocardial fibrosis induced by chronic iron overload (CIO) in mice. Kunming male mice (8 weeks old) were randomized to six groups of 10 animals each: control (CONT), CIO, low-dose SM (L-SM), high-dose SM (H-SM), verapamil (VRP) and deferoxamine (DFO) groups. Normal saline was injected in the CONT group. Mice in the other five groups were treated with iron dextran at 50 mg/kg per day intraperitoneally for 7 weeks, and those in the latter four groups also received corresponding daily treatments, including 3 g/kg or 6 g/kg of SM, 100 mg/kg of VRP, or 100 mg/kg of DFO. The iron deposition was estimated histologically using Prussian blue staining. Myocardial fibrosis was determined by Masson's trichrome staining and hydroxyproline (Hyp) quantitative assay. Superoxide dismutase (SOD) activity, malondialdehyde (MDA) content and protein expression levels of type I collagen (COL I), type I collagen (COL III), transforming growth factor-β1 (TGF-β1) and matrix metalloproteinase-9 (MMP-9) were analyzed to investigate the mechanisms underlying the effects of SM against iron-overloaded fibrosis. Treatment of chronic iron-overloaded mice with SM dose-dependently reduced iron deposition levels, fibrotic area percentage, Hyp content, expression levels of COL I and COL III, as well as upregulated the expression of TGF- β1 and MMP-9 proteins in the heart. Moreover, SM treatment decreased MDA content and increased SOD activity. In conclusion, SM exerted activities against cardiac fibrosis induced by CIO, which may be attributed to its inhibition of iron deposition, as well as collagen metabolism and oxidative stress.