Links between metabolic syndrome and cardiovascular autonomic dysfunction

Novel insights into the pathogenic impact of diabetes on the gastrointestinal tract

Type 2 and type 1 diabetes are common endocrine disorders with a progressively increasing incidence worldwide. These chronic, systemic diseases have multiorgan implications, and the whole gastrointestinal (GI) tract represents a frequent target in terms of symptom appearance and interdependent pathophysiological mechanisms. Metabolic alterations linked with diabetic complications, neuropathy and disrupted hormone homeostasis can lead to upper and/or lower GI symptoms in up to 75% of diabetic patients, with multifactorial involvement of the oesophagus, stomach, upper and lower intestine, and of the gallbladder. On the other hand, altered gastrointestinal motility and/or secretions are able to affect glucose and lipid homeostasis in the short and long term. Finally, diabetes has been linked with increased cancer risk at different levels of the GI tract. The presence of GI symptoms and a comprehensive assessment of GI function should be carefully considered in the management of diabetic patients to avoid further complications and to ameliorate the quality of life. Additionally, the presence of gastrointestinal dysfunction should be adequately managed to improve metabolic homeostasis, the efficacy of antidiabetic treatments and secondary prevention strategies.

Cardiovascular autonomic reflex tests and serum FGF21 levels in overweight and normal-weight men and women

OBJECTIVE

We evaluated cardiovascular autonomic reflexes and serum fibroblast growth factor 21 (FGF21), a surrogate marker of mitochondrial function, in a cohort of overweight and normal-weight adults (n = 42).

METHODS

Indices of autonomic function were monitored during supine rest, autonomic reflex tests and submaximal clinical exercise test, with heart rate variables and blood pressure measured with an automatic system.

RESULTS

Markers of sympathetic dominance were accentuated in overweight adults, including elevated resting low-frequency to the high-frequency ratio for heart rate variability (203 ± 227 vs. 96 ± 42; p = .01), and handgrip diastolic blood pressure (36 ± 15 mmHg vs. 25 ± 12 mmHg; p = .01). A weak non-significant trend has been found for a negative correlation between blood pressure responses to isometric handgrip test and FGF21 in the overweight group (r = -0.37; p = .09).

CONCLUSIONS

Excess body weight appears to trigger sympathetic overactivity in overweight adults, yet autonomic dysregulation might not be associated with notable changes in serum FGF21.

Orthostatic Hypotension and Novel Blood Pressure Associated Gene Variants in Older Adults: Data From the TILDA Study

Orthostatic hypotension (OH) is associated with increased risk of trauma and cardiovascular events. Recent studies have identified new genetic variants that influence orthostatic blood pressure (BP). The aim of this study was to investigate the associations of candidate gene loci with orthostatic BP responses in older adults. A total of 3,430 participants aged ≥50 years from The Irish Longitudinal Study on Ageing (TILDA) with BP measures and genetic data from 12 single-nucleotide polymorphism (SNP) linked to BP responses were analyzed. Orthostatic BP responses were recorded at each 10 s interval and were defined as OH (SBP drop ≥20 mmHg or DBP drop ≥10 mmHg) at the time-points 40, 90, and 110 s. We defined sustained OH (SOH) as a drop that exceeded consensus BP thresholds for OH at 40, 90, and 110 s after standing. Logistic regression analyses modeled associations between the candidate SNP alleles and OH. We report no significant associations between OH and measured SNPs after correction for multiple comparisons apart from the SNP rs5068 where proportion of the minor allele was significantly different between cases and controls for SOH 40 (p = .002). After adjustment for covariates in a logistic regression, those with the minor G allele (compared to the A allele) had a decreased incidence rate ratio (IRR) for SOH 40 (IRR 0.45, p = .001, 95% CI 0.29-0.72). Only one SNP linked with increased natriuretic peptide concentrations was associated with OH. These results suggest that genetic variants may have a weak impact on OH but needs verification in other population studies.

Conceptualization of a Parasympathetic Endocrine System

We here propose a parasympathetic endocrine system (PES) comprised of circulating peptides released from secretory cells in the gut, significantly modulated by vagal projections from the dorsal motor nucleus of the vagus (DMV). While most of these gut peptides mediate well-described satiety and digestive effects that increase parasympathetic control of digestion (Lee et al., 1994; Gutzwiller et al., 1999; Klok et al., 2007), they also have actions that are far-reaching and increase parasympathetic signaling broadly throughout the body. The actions beyond satiety that peptides like somatostatin, cholecystokinin, glucagon-like peptide 1, and vasoactive intestinal peptide have been well-examined, but not in a systematic way. Consideration has been given to the idea that these and other gut-derived peptides are part of an endocrine system has been partially considered (Rehfeld, 2012; Drucker, 2016), but that it is coordinated through parasympathetic control and may act to increase the actions of parasympathetic projections has not been formalized before. Here only gut-derived hormones are included although there are potentially other parasympathetically mediated factors released from other sites like lung and liver (Drucker, 2016). The case for the existence of the PES with the DMV as its integrative controller will be made through examination of an anatomical substrate and evidence of physiological control mechanisms as well as direct examples of PES antagonism of sympathetic signaling in mammals, including humans. The implications for this conceptual understanding of a PES reframe diseases like metabolic syndrome and may help underscore the role of the autonomic nervous system in the associated symptoms.

Body mass index interaction with SCN10A effects on cardiovascular autonomic neuropathy risk in a Chinese Han population

Background: The aim of this study was to estimate the extent to which the interaction between SCN10A (rs7375096) and body mass index (BMI) affects susceptibility to cardiovascular autonomic neuropathy (AN) in a Chinese Han sample.

Method: We conducted a large-scale, population-based study including 791 overweight patients and 1186 controls to analyze the interaction between SCN10A and BMI with regard to CAN. All participants were genotyped for the presence of SCN10A (rs7375036) polymorphisms. Univariate and multiple linear regression analyses were employed to detect these relationships. The interaction between rs7375036 and BMI with regard to CAN susceptibility on an additive scale was estimated by using the relative excess risk due to interaction, the proportion attributable to interaction, and the synergy index.

Results: Univariate analyses found no significant association between rs7375036 single nucleotide polymorphism and CAN. After controlling for potential confounding factors, the multiple linear regression analysis showed a significant association between BMI and CAN ([Formula: see text], OR = 1.121). In addition, a significant positive interaction effect of BMI and rs7375036 on CAN was detected ([Formula: see text]).

Conclusion: Our findings suggest that BMI and SCN10A (rs7375036) have interaction effects that influence the CAN.

The association and interaction analysis of hypertension and uric acid on cardiovascular autonomic neuropathy

BACKGROUND

The purpose of this study was to evaluate associations among hypertension (HTN) and uric acid (UA) with cardiovascular autonomic neuropathy (CAN), and to estimate the extent to which synergistic effects of HTN and UA affect the outcome in a Chinese population.

METHOD

We conducted a large-scale, population-based study to analyze the association and interaction of the two factors for CAN in a sample of 2092 Chinese people. Univariate and multiple linear regression (MLR) analysis were employed to detect these relationships. Interaction on an additive scale can be calculated by using the relative excess risk due to interaction (RERI), the proportion attributable to interaction (AP), and the synergy index (S).

RESULT

After adjusting for confounding factors, MLR showed that HTN was independently associated with CAN (P < 0.001). A significant interaction effect of UA and HTN on CAN was detected (P = 0.035; RETI = 1.483, 95 % CI 0.415-2.551; AP = 0.360, 95 % CI -0.043 to 0.76 and S = 1.908, 95 % CI 0.152-3.66).

CONCLUSION

Our findings suggest that HTN is independently and significantly associated with CAN and offer evidence to support the hypothesis that HTN and UA have interaction effects to influence the progression of CAN.

The association and interaction analysis of metabolic syndrome and chronic kidney disease on cardiovascular autonomic neuropathy in the general Chinese population

BACKGROUND

The objective of this study was to evaluate associations of metabolic syndrome (MetS) and chronic kidney disease (CKD) with cardiovascular autonomic neuropathy (CAN), and to estimate the extent to which interaction of MetS and CKD affects the outcome in the Chinese population.

METHOD

We conducted a large-scale, population-based study to analyze the association and interaction of the two factors for CAN in a sample of 2,092 Chinese people. Univariate and multiple linear regression (MLR) analysis were employed to detect these relationships. Interaction on an additive scale can be calculated by using the relative excess risk due to interaction (RERI), the proportion attributable to interaction (AP), and the synergy index (S).

RESULTS

MLR adjusted for confounding factors showed that MetS was independently associated with CAN (P < 0.001). A significant interaction effect was detected by MLR (P = 0.042). In addition, a positive interaction between MetS and CKD on CAN was estimated by using parameters of RETI = 0.119 (95% CI: 0.059-0.178), AP = 0.049 (95% CI: -0.039-0.138) and S = 1.091 (95% CI: 0.164-2.019).

CONCLUSION

Our findings suggest that MetS is independently associated with CAN and offer evidence to support the hypothesis that MetS and CKD have positive interactions on CAN.

Analysis of the Synergistic Effects of Fasting Plasma Glucose and Hypertension on Cardiovascular Autonomic Neuropathy

Background: The purpose of this study was to evaluate the associations of fasting plasma glucose (FPG) and hypertension (HTN) with cardiovascular autonomic neuropathy (CAN) and to estimate the extent to which the synergistic effects of FPG and HTN affect outcomes in a Chinese population. Method: We conducted a large-scale, population-based study to analyze the association and interaction of the two factors with CAN in a sample of 2,092 Chinese people. Univariate and multiple linear regression (MLR) analyses were employed to detect these relationships. Interaction on an additive scale can be calculated by using the relative excess risk due to interaction, the proportion attributable to interaction (AP), and the synergy index (S). Result: After adjusting for confounding factors, MLR showed that FPG and HTN were independently associated with CAN (p < 0.001 for both). A significant synergistic effect of FPG and HTN on CAN was detected (p = 0.046, RETI = 0.733, 95% CI 0.059-1.450; AP = 0.167, 95% CI -0.033 to 0.367; S = 1.275, 95% CI 0.140-2.410). Conclusion: Our findings suggest that FPG and HTN are independently associated with CAN, and they offer evidence to support the hypothesis that FPG and HTN have synergistic effects that influence the progression of CAN.

Clinical risk model assessment for cardiovascular autonomic dysfunction in the general Chinese population

BACKGROUND

The aim of this study was to evaluate the prevalence of cardiovascular autonomic (CA) dysfunction in the general Chinese population (instead of focusing on only patients with diabetes) and to develop a clinical risk model for the disease.

METHODS AND MATERIALS

We evaluated CA dysfunction prevalence in a dataset based on a population sample consisting of 2,092 individuals. Clinical risk models were derived from exploratory sets using multiple logistic regression analysis. The performance of the clinical risk models was tested in the validation sets.

RESULTS

CA dysfunction prevalence was 18.50% in the general Chinese population, while the prevalence was 24.14% in individuals aged ≥60 years. Its prevalence was 31.17, 24.69, and 21.26% in patients with diabetes, and hypertensive, and metabolic syndrome populations, respectively. Finally, we developed clinical risk models involving seven risk factors. The mean area under the receiver-operating curve was 0.758 (95% CI 0.724-0.793) for these models. The mean sensitivity and specificity of the clinical risk models was 75.0 and 66.2%, respectively.

CONCLUSION

CA dysfunction prevalence was high in the general Chinese population, and its prevalence was more frequent in individuals with diabetes, and hypertensive, and metabolic syndrome. Clinical risk models with a high value for predicting CA dysfunction were developed. CA dysfunction has become a major public health problem in China that requires strategies aimed at the prevention and treatment of the disease.

Bayesian estimation of cardiovascular autonomic neuropathy diagnostic test based on short-term heart rate variability without a gold standard

OBJECTIVE

To evaluate the reference values for short-term heart rate variability (HRV), estimate the performance of cardiovascular autonomic neuropathy (CAN) diagnostic tests in the absence of a gold standard, and assess CAN prevalence in our dataset.

SETTING

Community and hospital health centre.

PARTICIPANTS

Of 2092 subjects available for data analysis, 371 healthy subjects were selected so the reference values for the short-term HRV test could be evaluated. An external dataset contained 88 subjects who completed both the short-term HRV test and Ewing's test.

INTERVENTION

Collection of information on clinical outcome.

PRIMARY AND SECOND OUTCOME MEASURES

Cardiovascular autonomic function evaluated by using the short-term HRV test and/or Ewing's test.

RESULTS

Cut-off points of 356.13, 55.45 and 36.64 ms2 were set for total power, low frequency and high frequency (HF), respectively. The diagnostic test for CAN based on the mentioned reference value was created. The HRV test had a high sensitivity (80.01-85.09%) and specificity (82.30-85.20%) for CAN. In addition, the non-inferiority test rejected the null hypothesis that the performance of the HRV test was inferior to that of Ewing's test (p<0.05). The estimated CAN prevalence was 14.92% and 29.17% in the total sample and patients with diabetes, respectively.

CONCLUSIONS

Our findings provided reference values for short-term HRV, which were used for the CAN diagnostic test with high sensitivity and specificity. The estimated CAN prevalence was high in the Chinese population.

Normative reference of short-term heart rate variability and estimation of cardiovascular autonomic neuropathy prevalence in Chinese people

BACKGROUND

The cardiovascular autonomic neuropathy (CAN) prevalence is rapidly growing in all populations worldwide. This study aimed to evaluate the reference values for the short-term heart rate variable (HRV) and estimate CAN prevalence in our cross-sectional dataset.

METHODS

We conducted a large-scale, community-based, cross-sectional study in a Chinese population. Of 2,092 subjects available for data analysis, 371 healthy subjects were selected to reference the values for the short-term HRV. The short-term HRV analysis was performed for all subjects using a computer-aided examination and evaluation system for spectral analysis to investigate changes in autonomic regulation.

RESULTS

In the total sample, the reference value for total power was more than 356.13 ms(2). The cutoff points of 55.45 and 36.64 ms(2) were set for low frequency (LF) and high frequency (HF), respectively. The cutoff points of LFn and HFn were 6.40 and 4.83 ν, respectively. The normative reference of LF/HF ranged from 0.3 to 6.5. Using HRV test (model 1), the estimated age-adjusted CAN prevalence in the total sample was 16.83 %. The estimated age-adjusted CAN prevalence values were 31.07, 21.97 and 20.81 % in DM, HT, and MS patients, respectively.

CONCLUSION

Our findings provided reference values for short-term HRV. The estimated CAN prevalence was high in the Chinese population.

A simple Chinese risk score model for screening cardiovascular autonomic neuropathy

Background

The purpose of the present study was to develop and evaluate a risk score to predict people at high risk of cardiovascular autonomic dysfunction neuropathy (CAN) in Chinese population.

Methods and Materials

A population-based sample of 2,092 individuals aged 30–80 years, without previously diagnosed CAN, was surveyed between 2011 and 2012. All participants underwent short-term HRV test. The risk score was derived from an exploratory set. The risk score was developed by stepwise backward multiple logistic regression. The coefficients from this model were transformed into components of a CAN score. This score was tested in a validation and entire sample.

Results

The final risk score included age, body mass index, hypertension, resting hear rate, items independently and significantly (P<0.05) associated with the presence of previously undiagnosed CAN. The area under the receiver operating curve was 0.726 (95% CI 0.686–0.766) for exploratory set, 0.784 (95% CI 0.749–0.818) for validation set, and 0.756 (95% CI 0.729–0.782) for entire sample. In validation set, at optimal cutoff score of 5 of 10, the risk score system has the sensitivity, specificity, and percentage that needed subsequent testing were 69, 78, and 30%, respectively.

Conclusion

We developed a CAN risk score system based on a set of variables not requiring laboratory tests. The score system is simple fast, inexpensive, noninvasive, and reliable tool that can be applied to early intervention to delay or prevent the disease in China.

The analysis of a reference value for baroreflex sensitivity and cardiovascular autonomic neuropathy prevalence in a Chinese population

Background

Cardiovascular autonomic neuropathy (CAN) is rapidly growing in all populations worldwide. Baroreflex sensitivity (BRS) is easily applied as a diagnostic test to a large number of individuals in the general population. However, no study has reported the normal reference values of BRS for the CAN diagnostic test in a Chinese population. The aim of this study was to estimate the normative reference value of BRS, and assess CAN prevalence in our cross-sectional dataset.

Methods

We conducted a large-scale, community-based, cross-sectional study in a Chinese population. We performed data analysis on 2,092 subjects. Cardiovascular autonomic function was assessed using spontaneous BRS. A total of 349 healthy subjects were used to perform analysis for the reference value for BRS. The CAN prevalence was calculated in the overall sample, and in patients with diabetes mellitus, patients with hypertension and patients with metabolic syndrome.

Results

In the overall sample, the reference value for total power (TP.brs) was more than 1.96 ms/mmHg. The cut-off points of 1.74 ms/mmHg and 2.53 ms/mmHg were set as high frequency (HF.brs) and low frequency (LF.brs), respectively. CAN diagnostic tests based on the reference value were performed. The estimated CAN prevalence in the overall sample was 20.41% using the BRS test. CAN prevalence was 33.18%, 28.69% and 28.57% in patients with diabetes mellitus, patients with hypertension and patients with metabolic syndrome, respectively.

Conclusions

Our findings provided reference values for BRS. Estimated CAN prevalence was high in this Chinese population, which has become a major public health problem in China.

Association and predictive value analysis for resting heart rate and diabetes mellitus on cardiovascular autonomic neuropathy in general population

BACKGROUND

The purpose of this study was to evaluate the predictive value of DM and resting HR on CAN in a large sample derived from a Chinese population.

MATERIALS AND METHODS

We conducted a large-scale, population-based, cross-sectional study to explore the relationships of CAN with DM and resting HR. A total of 387 subjects were diagnosed with CAN in our dataset. The associations of CAN with DM and resting HR were assessed by a multivariate logistic regression (MLR) analysis (using subjects without CAN as a reference group) after controlling for potential confounding factors. The area under the receiver-operating characteristic curve (AUC) was used to evaluate the predictive performance of resting HR and DM.

RESULTS

A tendency toward increased CAN prevalence with increasing resting HR was reported (P for trend <0.001). MLR analysis showed that DM and resting HR were very significantly and independently associated with CAN (P < 0.001 for both). Resting HR alone or combined with DM (DM-HR) both strongly predicted CAN (AUC = 0.719, 95% CI 0.690-0.748 for resting HR and AUC = 0.738, 95% CI 0.710-0.766 for DM-HR).

CONCLUSION

Our findings signify that resting HR and DM-HR have a high value in predicting CAN in the general population.

Associations between the severity of metabolic syndrome and cardiovascular autonomic function in a Chinese population

BACKGROUND

The purpose of this study was to evaluate associations between the severity of metabolic syndrome (MetS) and cardiovascular autonomic function (CAF) in a Chinese population.

METHODS AND MATERIALS

We conducted a large-scale community-based cross-sectional study to estimate associations between MetS and CAF in a Chinese population. The study included 2119 subjects. MetS was defined in accordance with the criteria published by the International Diabetes Federation. CAF was assessed via heart rate variability (HRV) and baroreflex sensitivity (BRS). Univariate and multivariate linear regression (MLR) analyses were undertaken to evaluate the statistical significance of the associations investigated.

RESULTS

Three HRV components differed significantly between the groups with regard to MetS severity scores; total power (TP), low frequency power (LF), and high frequency power (HF), and BRS components also differed significantly between the groups (p<0.05 for each component). Univariate and MLR analysis revealed that MetS severity and insulin resistance (IR) were significantly associated with HRV and BRS components (β=-0.08~-0.16, p<0.05 for both). Fasting plasma glucose (FPG) and blood pressure (BP) were also negatively correlated with favorable outcomes (β=-0.042~-0.119, p<0.05 for both).

CONCLUSIONS

In this study, MetS and IR were each significantly and independently negatively associated with CAF. Two MetS components, FPG and BP, were negatively correlated with CAF. Also, decreased HRV and BRS components were associated with increased MetS severity scores.

The association and predictive value analysis of metabolic syndrome combined with resting heart rate on cardiovascular autonomic neuropathy in the general Chinese population

BACKGROUND

The purpose of this study was to explore the extent of associations of cardiovascular autonomic neuropathy (CAN) with metabolic syndrome (MetS) and resting heart reate (HR), and to evaluate the predictive value of MetS combined with HR on CAN in a large sample derived from a Chinese population.

MATERIALS AND METHODS

We conducted a large-scale, population-based, cross-sectional study to explore the relationships of CAN with MetS and resting HR. This study included 2092 participants aged 30-80 years, and a total of 387 subjects were diagnosed with CAN in our dataset. The associations of CAN with MetS and resting HR were assessed by a multivariate logistic regression (MLR) analysis (using subjects without CAN as a reference group) after controlling for potential confounding factors. The predictive performance of resting HR and MetS was evaluated using the area under the receiver-operating characteristic curve (AUC).

RESULTS

A tendency toward increased CAN prevalence with increasing resting HR was reported (p for trend < 0.001). MLR analysis showed that MetS and resting HR were very significantly and independently associated with CAN (β = 0.495 for MetS and β = 0.952 for HR, P < 0.001 for both). Resting HR alone and combined with MetS (MetS-HR) strongly predicted CAN (AUC = 0.719, P < 0.001 for resting HR and AUC = 0.735, P < 0.001 for MetS-HR).

CONCLUSION

Our findings signify that MetS and resting HR were very significantly and independently associated with CAN in the general Chinese population. Resting HR and MetS-HR both have a high value in predicting CAN in the general population.

Capsaicin-induced metabolic and cardiovascular autonomic improvement in an animal model of the metabolic syndrome

The metabolic syndrome (MetS) is associated with an increased risk of cardiac mortality, as it is characterised by the clustering of multiple cardiovascular risk factors. Studies have shown that capsaicin (red pepper) may be useful as a nutraceutical, ameliorating metabolic profile and cardiovascular function. The aim of the present study was to investigate the cardiovascular and metabolic effects of orally administered capsaicin in rats with the MetS. Neonate spontaneously hypertensive rats were injected with monosodium glutamate and subjected to one of the following three treatments by oral administration for 14 d, between 27 and 30 weeks: low-dose capsaicin (CAP05,n18, synthetic capsaicin powder diluted in a vehicle (10 % ethyl alcohol) plus 0·5 mg/kg body weight (BW) of capsaicin); high-dose capsaicin (CAP1,n19, synthetic capsaicin powder diluted in a vehicle (10 % ethyl alcohol) plus 1 mg/kg BW of capsaicin); control (C,n18, vehicle). Lee's index, lipid/metabolic profile, and cardiovascular parameters with the rats being conscious, including arterial pressure (AP) and heart rate (HR) variability, as well as aortic wall thickness (haematoxylin and eosin staining) and CD68 (cluster of differentiation 68) antibody levels (monocyte/macrophage immunostaining) were evaluated. Weight, Lee's index, and lipid and metabolic parameters, as well as AP and HR and aortic wall thickness, were similar between the groups. Capsaicin determined HR variability improvement (16·0 (sem9·0), 31·0 (sem28·2) and 31·3 (sem19·0) ms2for the C, CAP05 and CAP1 groups, respectively,P= 0·003), increased vascular sympathetic drive (low-frequency component of systolic AP variability: 3·3 (sem2·8), 8·2 (sem7·7) and 12·1 (sem8·8) mmHg2for the C, CAP05 and CAP1 groups, respectively,P< 0·001) and increased α-index (spontaneous baroreflex sensitivity). The present data show that capsaicin did not improve lipid and glucose abnormalities in rats with the MetS. However, beneficial cardiovascular effects were observed with this nutraceutical.

Comparison of prediction model for cardiovascular autonomic dysfunction using artificial neural network and logistic regression analysis

Background

This study aimed to develop the artificial neural network (ANN) and multivariable logistic regression (LR) analyses for prediction modeling of cardiovascular autonomic (CA) dysfunction in the general population, and compare the prediction models using the two approaches.

Methods and Materials

We analyzed a previous dataset based on a Chinese population sample consisting of 2,092 individuals aged 30–80 years. The prediction models were derived from an exploratory set using ANN and LR analysis, and were tested in the validation set. Performances of these prediction models were then compared.

Results

Univariate analysis indicated that 14 risk factors showed statistically significant association with the prevalence of CA dysfunction (P<0.05). The mean area under the receiver-operating curve was 0.758 (95% CI 0.724–0.793) for LR and 0.762 (95% CI 0.732–0.793) for ANN analysis, but noninferiority result was found (P<0.001). The similar results were found in comparisons of sensitivity, specificity, and predictive values in the prediction models between the LR and ANN analyses.

Conclusion

The prediction models for CA dysfunction were developed using ANN and LR. ANN and LR are two effective tools for developing prediction models based on our dataset.

Artificial neural network models for prediction of cardiovascular autonomic dysfunction in general Chinese population

BACKGROUND

The present study aimed to develop an artificial neural network (ANN) based prediction model for cardiovascular autonomic (CA) dysfunction in the general population.

METHODS

We analyzed a previous dataset based on a population sample consisted of 2,092 individuals aged 30-80 years. The prediction models were derived from an exploratory set using ANN analysis. Performances of these prediction models were evaluated in the validation set.

RESULTS

Univariate analysis indicated that 14 risk factors showed statistically significant association with CA dysfunction (P < 0.05). The mean area under the receiver-operating curve was 0.762 (95% CI 0.732-0.793) for prediction model developed using ANN analysis. The mean sensitivity, specificity, positive and negative predictive values were similar in the prediction models was 0.751, 0.665, 0.330 and 0.924, respectively. All HL statistics were less than 15.0.

CONCLUSION

ANN is an effective tool for developing prediction models with high value for predicting CA dysfunction among the general population.

Progressive cardiovascular autonomic dysfunction in rats with evolving metabolic syndrome

Metabolic syndrome is linked to increased cardiovascular mortality, which may be partially attributed to cardiac sympatho-vagal imbalance. However, autonomic changes were not evaluated during the metabolic syndrome development in a monosodium glutamate-induced animal model. We evaluate temporal changes in cardiovascular autonomic modulation in an animal model of metabolic syndrome. Eighteen neonate male spontaneously hypertensive rats (SHR) were treated with monosodium glutamate (MetS), and compared with Wistar-Kyoto (C) and saline-treated SHR (H). Lee index, insulin resistance and autonomic control (spectral analysis) were evaluated at 3 (3-mo), 6 (6-mo) and 9 (9-mo) months of age (compared by two-way ANOVA, p<0.05). Weight of visceral fat, Lee index and arterial pressure were higher in the MetS vs. C and H groups (p<0.001) at all ages. Heart rate variability (HRV) was decreased in the MetS and H groups at 3-mo and 9-mo vs. C. The LF component of HRV was reduced in the MetS group at 3-mo vs. C (p=0.032), and higher vs. C and H at 9-mo (p<0.001, all comparisons). H and MetS rats had a higher LF/HF index vs. C at 9-mo (p=0.001, all comparisons). The VLF component of systolic arterial pressure variability of the MetS was higher earlier (6-mo) than that of the H group. A reduction of 70%, 98% and 54% in αLF index of H and MetS rats vs. C, was observed at 3, 6 and 9 months, respectively. Metabolic syndrome and hypertension in rats evolve with progressive autonomic dysfunction (worst at 9 months), with specific derangements occurring very early.

Cardiovascular changes in animal models of metabolic syndrome

Metabolic syndrome has been defined as a group of risk factors that directly contribute to the development of cardiovascular disease and/or type 2 diabetes. Insulin resistance seems to have a fundamental role in the genesis of this syndrome. Over the past years to the present day, basic and translational research has used small animal models to explore the pathophysiology of metabolic syndrome and to develop novel therapies that might slow the progression of this prevalent condition. In this paper we discuss the animal models used for the study of metabolic syndrome, with particular focus on cardiovascular changes, since they are the main cause of death associated with the condition in humans.