Heart rate variability dynamics for the prognosis of cardiovascular risk

Statistical, spectral, multi-resolution and non-linear methods were applied to heart rate variability (HRV) series linked with classification schemes for the prognosis of cardiovascular risk. A total of 90 HRV records were analyzed: 45 from healthy subjects and 45 from cardiovascular risk patients. A total of 52 features from all the analysis methods were evaluated using standard two-sample Kolmogorov-Smirnov test (KS-test). The results of the statistical procedure provided input to multi-layer perceptron (MLP) neural networks, radial basis function (RBF) neural networks and support vector machines (SVM) for data classification. These schemes showed high performances with both training and test sets and many combinations of features (with a maximum accuracy of 96.67%). Additionally, there was a strong consideration for breathing frequency as a relevant feature in the HRV analysis.     

Heart rate variability signal processing: A quantitative approach as an aid to diagnosis in cardiovascular pathologies

The heart rate variability (HRV) signal carries important information about the systems controlling heat rate and blood pressure, mainly elicited by autonomic nervous system (sympathetic and parasympathetic) controls. The present paper illustrates methods of HRV signal processing by using autoregressive (AR) modeling and power spectral density estimate. The information enhanced in this way seems to be particularly sensitive in discriminating various cardiovascular pathologies (hypertension, myocardial infarction, diabetic neuropathy, etc.). This method provides a simple non-invasive analysis, based on the processing of spontaneous oscillations in heart rate. Particular emphasis is directed to the algorithms used and to their direct application by using proper computerized techniques: only a few paradigmatical examples will be illustrated as preliminary results.     

MicroRNA:新的心血管疾病生物标志物

近年来MicroRNA(miRNA)一直是医学生物学研究的热点。它作为一类非编码的小RNA,参与基因的转录和表达调控,因此人体的众多生命活动和疾病的发生、发展都与miRNA的变化密不可分。miRNA的作用因细胞特异性和目标mRNA的不同而异,miRNA可以通过影响细胞的分裂、增殖、凋亡和再生等表型的变化,参与疾病的损伤与修复过程。特别是近期研究人员进行了基于miRNA的疾病诊治研究,结果预示了良好的应用前景。     

High-density lipoprotein lipid peroxidation as a molecular signature of the risk for developing cardiovascular disease: Results from MASHAD cohort

High-density lipoprotein (HDL) function rather than level may better predict cardiovascular disease (CVD). However, the contribution of the impaired antioxidant function of HDL that is associated with increased HDL lipid peroxidation (HDLox) to the development of clinical CVD remains unclear. We have investigated the association between serum HDLox with incident CVD outcomes in Mashhad cohort. Three-hundred and thirty individuals who had a median follow-up period of 7 years were recruited as part of the cohort. The primary end point was cardiovascular event, including myocardial infarction, stable angina, unstable angina, or coronary revascularization. In both univariate/multivariate analyses adjusted for traditional CVD risk factors, HDLox was an independent risk factor for CVD (odds ratio, 1.62; 95% confidence interval, 1.41–1.86; p < 0.001). For every increase in HDLox by 0.1 unit, there was an increase in CVD risk by 1.62-fold. In an adjusted analysis, there was a >2.5-fold increase in cardiovascular risk in individuals with HDLox higher than cutoff point of 1.06 compared to those with lower scores, suggesting HDLox > 1.06 is related to the impaired HDL oxidant function and in turn exposed to elevated risk of CVD outcomes (hazard ratio, 2.72; 95% CI, 1.88–3.94). Higher HDLox is a surrogate measure of reduced HDL antioxidant function that positively associated with cardiovascular events in a population-based cohort.     

Heart energy metabolism impairment in Western-diet induced obese mice

Nutritional transition has contributed to growing obesity, mainly by changing eating habits of the population. The mechanisms by which diet-induced obesity leads to cardiac injury are not completely understood, but it is known that obesity is associated to impaired cardiac function and energy metabolism, increasing morbidity and mortality. Therefore, our study aimed to investigate the mechanisms underlying cardiac metabolism impairment related to Western diet-induced obesity. After weaning, male Swiss mice were fed a Western diet for 16 weeks in order to induce obesity. After this period, the content of proteins involved in heart energy metabolism GLUT1, cytosolic lysate and plasma membrane GLUT4, AMPK, pAMPK, IRβ, IRS-1, PGC-1α, CPT1 and UCP2 was evaluated. Also, the oxidative phosphorylation of myocardial fibers was measured by high-resolution respirometry. Mice in the Western diet group (WG) presented altered biometric parameters compared to those in control group, including higher body weight, increased myocardial lipid deposition and glucose intolerance, which demonstrate the obesogenic role of Western diet. WG presented increased CPT1 and UCP2 contents and decreased IRS-1, plasma membrane GLUT4 and PGC-1α contents. In addition, WG presented cardiac mitochondrial dysfunction and reduced biogenesis, demonstrating a lower capacity of carbohydrates and fatty acid oxidation and also decreased coupling between oxidative phosphorylation and adenosine triphosphate synthesis. Cardiac metabolism impairment related to Western diet-induced obesity is probably due to damaged myocardial oxidative capacity, reduced mitochondrial biogenesis and mitochondria uncoupling, which compromise the bioenergetic metabolism of heart.     

Plasma extracellular vesicle protein content for diagnosis and prognosis of global cardiovascular disease

Cardiovascular disease is a major public health problem worldwide. Its growing burden is particularly ominous in Asia, due to increasing rates of major risk factors such as diabetes, obesity and smoking. There is an urgent need for early identification and treatment of individuals at risk of adverse cardiovascular events. Plasma extracellular vesicle proteins are novel biomarkers that have been shown to be useful in the diagnosis, risk stratification and prognostication of patients with cardiovascular disease. Ongoing parallel biobank initiatives in European (the Netherlands) and Asian (Singapore) populations offer a unique opportunity to validate these biomarkers in diverse ethnic groups.     

Gender issues in cardiovascular diseases. Focus on energy metabolism

It is increasingly recognized that sex and gender differences (S&G) influence cardiovascular diseases (CVD), greatly impacting disease management. In terms of definition, sex refers to biological aspects, gender effects being mainly related to socio-cultural factors. Both sex and gender are interpenetrated in humans and difficult to separate. This is more clearly feasible in animal models where sex effects largely predominate. As alterations in energy metabolism are essential features of cardiovascular diseases, sexual dimorphism of energy metabolism and more specifically mitochondria occupies a place of choice. This review presents the basis of sex and gender differences in the cardiovascular pathophysiology, and how it mainly affects woman diseases, effectiveness of therapies and clinical outcome. These differences rely on complex molecular mechanisms that are still poorly understood because of the under-representation of females/women in experimental and clinical studies. Finally, the differing psychological and biological phases of woman's life are largely underestimated. This review presents an overview of the field with focus on differences in cardiac energy metabolism, which are illustrated with specific examples.     

Visual information without thermal energy may induce thermoregulatory-like cardiovascular responses

Background

Human core body temperature is kept quasi-constant regardless of varying thermal environments. It is well known that physiological thermoregulatory systems are under the control of central and peripheral sensory organs that are sensitive to thermal energy. If these systems wrongly respond to non-thermal stimuli, it may disturb human homeostasis.

Methods

Fifteen participants viewed video images evoking hot or cold impressions in a thermally constant environment. Cardiovascular indices were recorded during the experiments. Correlations between the ‘hot-cold’ impression scores and cardiovascular indices were calculated.

Results

The changes of heart rate, cardiac output, and total peripheral resistance were significantly correlated with the ‘hot-cold’ impression scores, and the tendencies were similar to those in actual thermal environments corresponding to the impressions.

Conclusions

The present results suggest that visual information without any thermal energy can affect physiological thermoregulatory systems at least superficially. To avoid such ‘virtual’ environments disturbing human homeostasis, further study and more attention are needed.     

Model-based cardiovascular disease diagnosis: a preliminary in-silico study

In this study, we developed and examined the feasibility of a model-based system identification approach to cardiovascular disease diagnosis. The basic premise of the approach is that it may be possible to diagnose cardiovascular disease from disease-induced alterations in the arterial mechanical properties manifested in the proximal and distal arterial blood pressure waveforms. It first individualizes the lumped-parameter model of wave propagation and reflection in the artery using the measurement of proximal and distal arterial blood pressure waveforms. Then, it employs a diagnosis logic, in the form of disease-specific patterns in model parameters, referred as \(\alpha , \beta \) and pulse transit time. The longitudinal change in these parameters is used to diagnose the presence of peripheral artery disease and arterial stiffening. We illustrated the feasibility of the proposed approach by testing it in a full-scale in-silico arterial tree simulation. The results showed that the approach exhibited superior sensitivity to ankle-brachial index and convenience to carotid-femoral pulse wave velocity: The model parameters \(\alpha \) and \(\beta \) responded with up to 100 and 40 % changes to peripheral artery disease with up to 50 % arterial blockage whereas the change in ankle-brachial index was \({<}5\,\%\); the same parameters responded with up to 300 and 40 % changes to up to 100 % arterial stiffening while pulse transit time changed by up to 24 %. Together with the development of more convenient techniques for the measurement of arterial blood pressure waveforms, the proposed approach may evolve into a viable alternative to the state-of-the-art techniques for cardiovascular disease diagnosis.     

Variability in the performance of the spectrogram correlation detector for North-east Pacific blue whale calls

Spectrogram correlation has been used successfully for automatic detection of baleen whale calls. However, applying this method consistently to long time series can be challenging. To illustrate the potential challenges of the automatic detection process, recordings collected in the Southern California Bight between 2007 and 2012 were used for detection of North-east Pacific blue whale (Balaenoptera musculus) B calls. The effects of the following factors were investigated: blue whale B call frequency shift and appropriate kernel modification, seasonal variability in call abundance, analyst variability and noise. Due to intra- and inter-annual changes in the call frequency of blue whale B calls, seasonal and annual adjustments to the call detection kernel were needed. To account for seasonal variability in call production, evaluation of the detector against ground truth data was performed at multiple times during the year. Analyst variability did not affect overall long-term trends in detection, but it had an impact on the total number of detections, as well as call rate estimation. Noise, particularly from shipping, was negatively correlated with detections at hourly time scales. A detailed analysis of variability in the performance of spectrogram correlation detectors should be performed when applying this method to long-term acoustic data-sets.     

Effect of Red Bull energy drink on cardiovascular and renal function

Energy drink consumption has been anecdotally linked to the development of adverse cardiovascular effects in consumers, although clinical trials to support this link are lacking. The effects of Red Bull^® energy drink on cardiovascular and neurologic functions were examined in college-aged students enrolled at Winona State University. In a double-blind experiment where normal calorie and low calorie Red Bull^® were compared to normal and low calorie placebos, no changes in overall cardiovascular function nor blood glucose (mg/dL) were recorded in any participant (n = 68) throughout a 2-h test period. However, in the second experiment, nine male and twelve female participants subjected to a cold pressor test (CPT) before and after Red Bull^® consumption showed a significant increase in blood sugar levels pre- and post Red Bull^® consumption. There was a significant increase in diastolic blood pressure of the male volunteers immediately after submersion of the hand in the 5°C water for the CPT. Under the influence of Red Bull^®, the increase in diastolic pressure for the male participants during the CPT was negated. There were no significant changes in the blood pressure of the female participants for the CPT with or without Red Bull^®. Finally, the CPT was used to evaluate pain threshold and pain tolerance before and after Red Bull^® consumption. Red Bull^® consumption was associated with a significant increase in pain tolerance in all participants. These findings suggest that Red Bull^® consumption ameliorates changes in blood pressure during stressful experiences and increases the participants’ pain tolerance.     

血浆游离DNA检测在心血管系统疾病诊断中的应用

心血管疾病发病率和病死率居高不下,寻求敏感性高的生物学指标帮助早期诊断和改善预后意义重大.血浆游离DNA(cell-free DNA,cfDNA)是一类存在于血浆、尿液及其他体液中游离于细胞之外的双链DNA片段.血浆cfDNA水平在心血管疾病的早期明显升高,提示其可能是心血管疾病的潜在生物标志物.为了更深入理解cfDN...     

Tenascin-C in cardiovascular remodeling: potential impact for diagnosis,prognosis estimation and targeted therapy

Fetal variants of tenascin-C are not expressed in healthy adult myocardium. But, there is a relevant re-occurrence during pathologic cardiac tissue and vascular remodeling. Thus, these molecules, in particular B and C domain containing tenascin-C, might qualify as promising novel biomarkers for diagnosis and prognosis estimation. Since a stable extracellular deposition of fetal tenascin-C variants is present in diseased cardiac tissue, the molecules are excellent target structures for antibody-based delivery of diagnostic (e.g., radionuclides) or therapeutic (bioactive payloads) agents directly to the site of disease. Against the background that fetal tenascin-C variants are functionally involved in cardiovascular tissue remodeling, therapeutic functional blocking strategies could be experimentally tested in the future.     

Diaphragm‐based optical fiber sensor for pulse wave monitoring and cardiovascular diseases diagnosis

Arterial pulse wave has been considered as a vital sign in assessment of cardiovascular diseases. Noninvasive pulse sensor with compact structure, immunity to electro‐magnetic interference and high sensitivity is the research focus in recent years. While, optical fiber biosensor is a competitive option to meet these needs. Here, a diaphragm‐based optical fiber pulse sensor was proposed to achieve high‐precision radial pulse wave monitoring. A wearable device was developed, composed of a sports wristband and an aluminum diaphragm‐based optical fiber sensor tip of only 1 cm in diameter, which was highly sensitive to the weak acoustic signal. In particular, coherent phase detection was adopted to improve detection signal‐to‐noise ratio, so as to recover the high‐fidelity pulse waveforms. A clinical experiment was carried out to detect and morphological analyze the pulse waveforms of four subjects, the results of which preliminarily demonstrated the feasibility of pulse diagnosis method. The proposed pulse fiber sensor provides a comfortable way for pulse diagnosis, which is promising in early cardiovascular diseases indicating.