Sex-related differences of fatty acid-binding protein 4 and leptin levels in atrial fibrillation.

AIMS: Adiposity plays a key role in the pathogenesis of atrial fibrillation (AF). Our aim was to study the sex differences in adipokines levels according to AF burden. METHODS AND RESULTS: Two independent cohorts of patients were studied: (i) consecutive patients with AF undergoing catheter ablation (n = 217) and (ii) a control group (n = 105). (i) Adipokines, oxidative stress, indirect autonomic markers, and leucocytes mRNA levels were analysed; (ii) correlation between biomarkers was explored with heatmaps and Kendall correlation coefficients; and (iii) logistic regression and random forest model were used to determine predictors of AF recurrence after ablation. Our results showed that: (i) fatty acid-binding protein 4 (FABP4) and leptin levels were higher in women than in men in both cohorts (P < 0.01). In women, FABP4 levels were higher on AF cohort (20 ± 14 control, 29 ± 18 paroxysmal AF and 31 ± 17 ng/mL persistent AF; P < 0.01). In men, leptin levels were lower on AF cohort (22 ± 15 control, 13 ± 16 paroxysmal AF and 13 ± 11 ng/mL persistent AF; P < 0.01). (ii) In female with paroxysmal AF, there was a lower acetylcholinesterase and higher carbonic anhydrase levels with respect to men (P < 0.05). (iii) Adipokines have an important role on discriminate AF recurrence after ablation. In persistent AF, FABP4 was the best predictor of recurrence after ablation (1.067, 95% confidence interval 1-1.14; P = 0.046). CONCLUSION: The major finding of the present study is the sex-based differences of FABP4 and leptin levels according to AF burden. These adipokines are associated with oxidative stress, inflammatory and autonomic indirect markers, indicating that they may play a role in AF perpetuation.

microRNA-206 correlates with left ventricular function after transcatheter aortic valve implantation.

Transcatheter aortic valve implantation (TAVI) is the method of choice in patients with high risk or contraindications for conventional aortic valve replacement. However, it is not well understood which parameters predict the overall cardiac function postprocedurally. miRNAs are small noncoding RNA molecules that repress gene expression by different mechanisms and can also be detected in the blood. Recent studies have shown that miRNAs detected in the blood may serve as sensitive and specific biomarkers in various diseases; therefore, we examined the levels of different microRNAs in the serum of patients undergoing TAVI. We thereby intended to find potential predictors for cardiac function after TAVI. Serum from patients with aortic valve disease was obtained at five different points: before the TAVI procedure, at days 1 and 3 after the TAVI procedure, and the day of dischargement and after a period of 3 mo. We next performed quantitative real-time PCRs to examine the samples for changes in the level of miRNAs previously described as cardiac enriched. Our results show that the level of miR-206 in the serum of patients after TAVI correlated negatively with the left ventricular ejection fraction of individual patients. We found left ventricular function to be better in patients with lower levels of miR-206 after implantation of the new valve. A decrease in the serum level of miR-206 may be linked to changes in cardiac function of patients after TAVI. Further studies are necessary to test the miRNA for its potential value as a prognostic marker. NEW & NOTEWORTHY This study is the first to investigate novel miRNA-based biomarkers within the context of transcatheter aortic valve implantation. miRNA-206 proved to correlate inversely with the postprocedural left ventricular ejection fraction of patients.

Conformational and thermal characterization of left ventricle remodeling post-myocardial infarction.

Adverse cardiac remodeling after myocardial infarction (MI) causes impaired ventricular function and heart failure. Histopathological characterization is commonly used to detect the location, size and shape of MI sites. However, the information about chemical composition, physical structure and molecular mobility of peri- and infarct zones post-MI is rather limited. The main objective of this work was to explore the spatiotemporal biochemical and biophysical alterations of key cardiac components post-MI. The FTIR spectra of healthy and remote myocardial tissue shows amides A, I, II and III associated with proteins in freeze-died tissue as major absorptions bands. In infarcted myocardium, the spectrum of these main absorptions was deeply altered. FITR evidenced an increase of the amide A band and the distinct feature of the collagen specific absorption band at 1338cm-1 in the infarct area at 21days post-MI. At 21days post-MI, it also appears an important shift of amide I from 1646cm-1 to 1637cm-1 that suggests the predominance of the triple helical conformation in the proteins. The new spectra bands also indicate an increase in proteoglycans, residues of carbohydrates in proteins and polysaccharides in ischemic areas. Thermal analysis indicates a deep increase of unfreezable water/freezable water in peri- and infarcted tissues. In infarcted tissue is evidenced the impairment of myofibrillar proteins thermal profile and the emergence of a new structure. In conclusion, our results indicate a profound evolution of protein secondary structures in association with collagen deposition and reorganization of water involved in the scar maturation of peri- and infarct zones post-MI.

Autophagic and proteolytic processes in the Harderian gland are modulated during the estrous cycle.

The Syrian hamster Harderian gland (HG) is an organ that undergoes physiological autophagy in response to oxidative stress induced by porphyrin production. Porphyrin production in the HG has marked sex differences and is closely linked to reproductive function. In the present study, we observed that the estrous cycle and associated estrogen variations may affect oxidative-stress-induced proteolytic processes. In particular, significant changes in autophagic activity were detected during the estrous cycle. Notably, increased activation of macroautophagy as well as chaperone-mediated autophagy in the estrus phase coincided with a minimal antioxidant capability and the highest protein damage levels. By contrast, autophagic machinery was found to be blocked in the diestrus phase, likely due to mammalian target of rapamycin activation, which could be corroborated by the subsequent pS6K activation. Analogous results were observed regarding proteasome activity, which also showed maximal activity in the estrus phase. Interestingly, all these mechanisms were associated with important morphological changes in the HG during the estrous cycle. We observed statistically significant increases in Type II cells, which may be related to extensive autophagy in the estrus phase. Physiologically, this would result in a significant release of porphyrins specifically when females are more receptive. These data support the role of porphyrins as pheromones, as other authors have previously suggested, thus making the HG a scent organ. In addition, these results suggest a porphyrin-based approach to the treatment of porphyria during pregnancy, a condition for which no treatment is currently known.

Risk factors associated with mortality among elderly patients with COVID-19: Data from 55 intensive care units in Spain.

INTRODUCTION AND OBJECTIVES: Critically-ill elderly ICU patients with COVID-19 have poor outcomes. We aimed to compare the rates of in-hospital mortality between non-elderly and elderly critically-ill COVID-19 ventilated patients, as well as to analyze the characteristics, secondary outcomes and independent risk factors associated with in-hospital mortality of elderly ventilated patients. PATIENTS AND METHODS: We conducted a multicentre, observational cohort study including consecutive critically-ill patients admitted to 55 Spanish ICUs due to severe COVID-19 requiring mechanical ventilation (non-invasive respiratory support [NIRS; include non-invasive mechanical ventilation and high-flow nasal cannula] and invasive mechanical ventilation [IMV]) between February 2020 and October 2021. RESULTS: Out of 5,090 critically-ill ventilated patients, 1,525 (27%) were aged ≥70 years (554 [36%] received NIRS and 971 [64%] received IMV. In the elderly group, median age was 74 years (interquartile range 72-77) and 68% were male. Overall in-hospital mortality was 31% (23% in patients <70 years and 50% in those ≥70 years; p<0.001). In-hospital mortality in the group ≥70 years significantly varied according to the modality of ventilation (40% in NIRS vs. 55% in IMV group; p<0.001). Factors independently associated with in-hospital mortality in elderly ventilated patients were age (sHR 1.07 [95%CI 1.05-1.10], p<0.001); previous admission within the last 30 days (sHR 1.40 [95%CI 1.04-1.89], p = 0.027); chronic heart disease (sHR 1.21 [95%CI 1.01-1.44], p = 0.041); chronic renal failure (sHR 1.43 [95%CI 1.12- 1.82], p = 0.005); platelet count (sHR 0.98 [95% CI 0.98-0.99], p<0.001); IMV at ICU admission (sHR 1.41 [95% CI 1.16- 1.73], p<0.001); and systemic steroids (sHR 0.61 [95%CI 0.48- 0.77], p<0.001). CONCLUSIONS: Amongst critically-ill COVID-19 ventilated patients, those aged ≥70 years presented significantly higher rates of in-hospital mortality than younger patients. Increasing age, previous admission within the last 30 days, chronic heart disease, chronic renal failure, platelet count, IMV at ICU admission and systemic steroids (protective) all comprised independent factors for in-hospital mortality in elderly patients.

Circulating MicroRNA Profile Associated with Obstructive Sleep Apnea in Alzheimer's Disease.

The diagnosis of obstructive sleep apnea (OSA) in Alzheimer's disease (AD) by polysomnography (PSG) is challenging due to the required collaboration of the patients. In addition, screening questionnaires have demonstrated limited usefulness with this subpopulation. Considering this, we investigated the circulating microRNA (miRNA) profile associated with OSA in AD patients. This study included a carefully selected cohort of females with mild-moderate AD confirmed by biological evaluation (n = 29). The individuals were submitted to one-night PSG to diagnose OSA (apnea-hypopnea index ≥ 15/h) and the blood was collected in the following morning. The plasma miRNA profile was evaluated using RT-qPCR. The patients had a mean (SD) age of 75.8 (5.99) years old with a body mass index of 28.6 (3.83) kg m-2. We observed a subset of 15 miRNAs differentially expressed between OSA and non-OSA patients, of which 10 were significantly correlated with the severity of OSA. Based on this, we built a prediction model that generated an AUC (95% CI) of 0.95 (0.88-1.00) including 5 of the differentially expressed miRNAs that correlated with OSA severity: miR-26a-5p, miR-30a-3p, miR-374a-5p, miR-377-3p, and miR-545-3p. Our preliminary results suggest a plasma miRNA signature associated with the presence of OSA in AD patients. Further studies will be necessary to validate these findings.

Identification and validation of endogenous control miRNAs in plasma samples for normalization of qPCR data for Alzheimer's disease.

BACKGROUND: MicroRNAs (miRNAs) are noncoding RNAs that are highly relevant as disease biomarkers. Several studies that explored the role of miRNAs in Alzheimer's disease (AD) demonstrated their usefulness in clinical identification. Nevertheless, miRNAs that may act as endogenous controls (ECs) have not yet been established. The identification of ECs would contribute to the standardization of these biomarkers in AD. The objective of the study was to identify miRNAs that can be used as ECs in AD. METHODS: We evaluated 145 patients divided into two different cohorts. One was a discovery cohort of 19 women diagnosed with mild to moderate AD (Mini-Mental State Examination (MMSE) score ≥ 20) and with confirmed pathologic levels of Aß42 in CSF. The stability assessment cohort consisted of 126 individuals: 24 subjects without AD or any kind of dementia and negative for all core CSF biomarkers of AD, 25 subjects with MCI and negative for CSF biomarkers (MCI -), 22 subjects with MCI and positive for CSF biomarkers (MCI +), and 55 subjects with AD and positive for CSF biomarkers. In the discovery cohort, a profile of 384 miRNAs was determined in the plasma by TaqMan low-density array. The best EC candidates were identified by mean-centering and concordance correlation restricted normalization methods. The stability of the EC candidates was assessed using the GeNorm, BestKeeper, and NormFinder algorithms. RESULTS: Nine miRNAs (hsa-miR-324-5p, hsa-miR-22-5p, hsa-miR-103a-2-5p, hsa-miR-362-5p, hsa-miR-425-3p, hsa-miR-423-5p, hsa-let-7i-3p, hsa-miR-532-5p, and hsa-miR-1301-3p) were identified as EC candidates in the discovery cohort. The validation results indicated that hsa-miR-103a-2-5p was the best EC, followed by hsa-miR-22-5p, hsa-miR-1301-3p, and hsa-miR-425-3p, which had similar stability values in all three algorithms. CONCLUSIONS: We identified a profile of four miRNAs as potential plasma ECs to be used for normalization of miRNA expression data in studies of subjects with cognitive impairment.

Serum microRNA-1 and microRNA-133a levels reflect myocardial steatosis in uncomplicated type 2 diabetes.

Using in vitro, in vivo and patient-based approaches, we investigated the potential of circulating microRNAs (miRNAs) as surrogate biomarkers of myocardial steatosis, a hallmark of diabetic cardiomyopathy. We analysed the cardiomyocyte-enriched miRNA signature in serum from patients with well-controlled type 2 diabetes and with verified absence of structural heart disease or inducible ischemia, and control volunteers of the same age range and BMI (N = 86), in serum from a high-fat diet-fed murine model, and in exosomes from lipid-loaded HL-1 cardiomyocytes. Circulating miR-1 and miR-133a levels were robustly associated with myocardial steatosis in type 2 diabetes patients, independently of confounding factors in both linear and logistic regression analyses (P < 0.050 for all models). Similar to myocardial steatosis, miR-133a levels were increased in type 2 diabetes patients as compared with healthy subjects (P < 0.050). Circulating miR-1 and miR-133a levels were significantly elevated in high-fat diet-fed mice (P < 0.050), which showed higher myocardial steatosis, as compared with control animals. miR-1 and miR-133a levels were higher in exosomes released from lipid-loaded HL-1 cardiomyocytes (P < 0.050). Circulating miR-1 and miR-133a are independent predictors of myocardial steatosis. Our results highlight the value of circulating miRNAs as diagnostic tools for subclinical diabetic cardiomyopathy.

Familial dilated cardiomyopathy: A multidisciplinary entity, from basic screening to novel circulating biomarkers.

Idiopathic dilated cardiomyopathy has become one of the most prevalent inherited cardiomyopathies over the past decades. Genetic screening of first-degree relatives has revealed that 30-50% of the cases have a familial origin. Similar to other heart diseases, familial dilated cardiomyopathy is characterized by a high genetic heterogeneity that complicates family studies. Cli'nical screening, 12-lead electrocardiogram and transthoracic echocardiogram are recommended for patients and first-degree family members. Magnetic resonance also needs to be considered. Genetic technologies have become fundamental for the clinical management of this disease. New generation sequencing methods have made genetic testing feasible for extensive panels of genes related to the disease. Recently, new imaging modalities such as speckle-tracking, strain and strain rate or magnetic resonance, and circulating biomarkers such as non-coding RNAs, have emerged as potential strategies to help cardiologists in their clinical practice. Imaging, genetic and blood-based techniques should be considered together in the evaluation and testing of familial dilated cardiomyopathy. Here, we discuss the current procedures and novel approaches for the clinical management of familial dilated cardiomyopathy.

Circulating long-non coding RNAs as biomarkers of left ventricular diastolic function and remodelling in patients with well-controlled type 2 diabetes.

Contractile dysfunction is underdiagnosed in early stages of diabetic cardiomyopathy. We evaluated the potential of circulating long non-coding RNAs (lncRNAs) as biomarkers of subclinical cardiac abnormalities in type 2 diabetes. Forty-eight men with well-controlled type 2 diabetes and 12 healthy age-matched volunteers were enrolled in the study. Left ventricular (LV) parameters were measured by magnetic resonance imaging. A panel of lncRNAs was quantified in serum by RT-qPCR. No differences in expression levels of lncRNAs were observed between type 2 diabetes patients and healthy volunteers. In patients with type 2 diabetes, long intergenic non-coding RNA predicting cardiac remodeling (LIPCAR) was inversely associated with diastolic function, measured as E/A peak flow (P < 0.050 for all linear models). LIPCAR was positively associated with grade I diastolic dysfunction (P < 0.050 for all logistic models). Myocardial infarction-associated transcript (MIAT) and smooth muscle and endothelial cell-enriched migration/differentiation-associated long noncoding RNA (SENCR) were directly associated with LV mass to LV end-diastolic volume ratio, a marker of cardiac remodelling (P < 0.050 for all linear models). These findings were validated in a sample of 30 patients with well-controlled type 2 diabetes. LncRNAs are independent predictors of diastolic function and remodelling in patients with type 2 diabetes.

Circulating soluble low-density lipoprotein receptor-related protein 1 (sLRP1) concentration is associated with hypercholesterolemia: A new potential biomarker for atherosclerosis.

BACKGROUND: There is clinical interest in identifying novel lipid biomarkers for evaluating cardiovascular risk and targeting lipid-lowering treatment. Low-density lipoprotein receptor-related protein 1 (LRP1) plays a crucial role in the dysregulated cholesterol transfer from modified lipoproteins to human coronary vascular smooth muscle cells (hVSMCs), promoting hVSMC-derived foam cell formation. LRP1 has a soluble and circulating form (sLRP1) generated from LRP1. Cholesterol modulates the release of the soluble form of LRP1. Using in vitro, ex vivo and patient-based approaches, we tested the association between circulating sLRP1 concentrations and hypercholesterolemia and the potential of sLRP1 as a biomarker of atherosclerosis. METHODS AND RESULTS: Circulating sLRP1 concentrations were higher in severe hypercholesterolemia compared to moderate hypercholesterolemia or normocholesterolemia (Study 1). Circulating sLRP1 was significantly associated with established pro-atherogenic lipid parameters in two different hypercholesterolemic populations (Studies 2 and 3). sLRP1 concentrations decreased after statin treatment and increased after statin withdrawal (Study 3). In vitro experiments showed that native LDL, aggregated LDL and VLDL+IDL lipoproteins induced the release of sLRP1 from hVSMC. sLRP1 levels were increased in the conditioned medium of coronary atherosclerotic plaque areas extracted from patients compared to non-atherosclerotic areas of the same coronary artery and patient. Circulating sLRP1 concentrations were independently associated with the occurrence of carotid atherosclerosis in a hypercholesterolemic population (Study 2). The later association was higher than that observed for other classical or novel lipid parameters. CONCLUSIONS: Circulating sLRP1 is a new lipid-related parameter potentially useful as a biomarker for atherosclerosis.

Physical Activity as Healthy Intervention Against Severe Oxidative Stress in Elderly Population.

Severe oxidative stress is a relevant risk factor for major deleterious health-related events in older people and is thought to be an important contributor to age-related disease. Literature has suggested oxidative stress as a therapeutic target for mitigating the biological decline and attenuating the occurrence of adverse clinical events in aged individuals. However, definitive treatments are not known. Regular and moderate physical activity has been proposed as possible intervention for slowing age-related decline. This healthy strategy presents a wide range of beneficial aspects for elderly, from the reduction of morbidity, disability, frailty and mortality rates to treatment of many age-related disorders. Importantly, the global benefits on health are not shared by any other strategies. Nevertheless, the physiological basis by which exercise produces its benefits to the organism is not fully understood. This review summarizes the evidence for the role of physical activity as potential healthy intervention for mitigating the negative aspects of aging through the modulation of the oxidative mechanisms.