Predictive markers of abdominal aortic stiffness measured by echo-tracking in subjects with varying insulin sensitivity

Association of monocyte-to-high density lipoprotein ratio with arterial stiffness in patients with diabetes

BACKGROUND

Previous studies proposed that chronic inflammation in diabetes has a role in abnormal collagen production and elastin degradation, which promotes arterial stiffness. Monocyte-to-High Density Lipoprotein cholesterol ratio (MHR) is a simple measurement associated with inflammation and oxidative stress. However, little is known about the relationship of MHR with arterial stiffness. This study aimed to determine the association of MHR with arterial stiffness in patients with diabetes.

METHODS

A total of 81 patients with type 2 diabetes mellitus were enrolled in a cross-sectional study. Arterial stiffness factor in this study was Cardio Ankle Vascular Index (CAVI). We analyzed complete blood count and lipid profile in all participants, then performed statistical analysis to determine the relationship between MHR and CAVI. Receiver operating characteristic (ROC) analysis was used to estimate the cut-off values of MHR to predict CAVI ≥ 9.

RESULTS

Median of MHR in this study was 11.91 with the mean of CAVI was 8.13 ± 0.93. Spearman correlation analysis revealed a significant positive correlation between MHR and CAVI (ρ = 0.239, p = 0.031). Multivariate analysis showed the independent association of MHR to arterial stiffness (β = 0.361, 95% CI 0.023-0.093) and to CAVI ≥ 9 (OR 1.181, 95% CI 1.047-1.332). The cut-off values of MHR for predicting CAVI ≥ 9 were identified as ≥ 13 (OR 3.289, 95% CI 1.036-10.441).

CONCLUSION

MHR is associated with CAVI in patients with diabetes, irrespective of various potential confounders.

Obesity and cardiovascular disease in women

As the prevalence of obesity continues to grow worldwide, the health and financial burden of obesity-related comorbidities grows too. Cardiovascular disease (CVD) is clearly associated with increased adiposity. Importantly, women are at higher risk of CVD when obese and insulin resistant, in particular at higher risk of developing heart failure with preserved ejection fraction and ischemic heart disease. Increased aldosterone and mineralocorticoid receptor activation, aberrant estrogenic signaling and elevated levels of androgens are among some of the proposed mechanisms explaining the heightened CVD risk. In addition to traditional cardiovascular risk factors, understanding nontraditional risk factors specific to women, like excess weight gain during pregnancy, preeclampsia, gestational diabetes, and menopause are central to designing personalized interventions aimed to curb the epidemic of CVD. In the present review, we examine the available evidence supporting a differential cardiovascular impact of increased adiposity in women compared with men and the proposed pathophysiological mechanisms behind these differences. We also discuss women-specific cardiovascular risk factors associated with obesity and insulin resistance.

Sexual Dimorphism in Obesity-Associated Endothelial ENaC Activity and Stiffening in Mice

Obesity and insulin resistance stiffen the vasculature, with females appearing to be more adversely affected. As augmented arterial stiffness is an independent predictor of cardiovascular disease (CVD), the increased predisposition of women with obesity and insulin resistance to arterial stiffening may explain their heightened risk for CVD. However, the cellular mechanisms by which females are more vulnerable to arterial stiffening associated with obesity and insulin resistance remain largely unknown. In this study, we provide evidence that female mice are more susceptible to Western diet-induced endothelial cell stiffening compared with age-matched males. Mechanistically, we show that the increased stiffening of the vascular intima in Western diet-fed female mice is accompanied by enhanced epithelial sodium channel (ENaC) activity in endothelial cells (EnNaC). Our data further indicate that: (i) estrogen signaling through estrogen receptor α (ERα) increases EnNaC activity to a larger extent in females compared with males, (ii) estrogen-induced activation of EnNaC is mediated by the serum/glucocorticoid inducible kinase 1 (SGK-1), and (iii) estrogen signaling stiffens endothelial cells when nitric oxide is lacking and this stiffening effect can be reduced with amiloride, an ENaC inhibitor. In aggregate, we demonstrate a sexual dimorphism in obesity-associated endothelial stiffening, whereby females are more vulnerable than males. In females, endothelial stiffening with obesity may be attributed to estrogen signaling through the ERα-SGK-1-EnNaC axis, thus establishing a putative therapeutic target for female obesity-related vascular stiffening.

Removal of interscapular brown adipose tissue increases aortic stiffness despite normal systemic glucose metabolism in mice

Brown adipose tissue (BAT) is considered protective against obesity and related cardiometabolic dysfunction. Indeed, activation of BAT improves glucose homeostasis and attenuates cardiovascular disease development. However, whether a reduction in BAT mass perturbs metabolic function and increases risk for cardiovascular disease remains largely unknown. To address this question, C57BL/6J male mice underwent a sham procedure or surgical bilateral excision of interscapular BAT (iBATx) and were fed a normal chow or a Western diet for 18 wk, creating four groups ( n = 10/group). Mice were housed at 25°C. As expected, the Western diet increased final body weight and adiposity; however, contrary to our hypothesis, iBATx did not potentiate adiposity independent of diet. Furthermore, iBATx did not affect indexes of glycemic control (HbA_1c, fasting glucose and insulin, and glucose area under the curve during a glucose tolerance test) and produced minimal-to-no effects on lipid homeostasis. The absence of metabolic disturbances with iBATx was not attributed to regrowth of iBAT or a "browning" or proliferative compensatory response of other BAT depots. Notably, iBATx caused an increase in aortic stiffness in normal chow-fed mice only, which was associated with an increase in aortic uncoupling protein-1. Collectively, we demonstrated that, at 25°C (i.e., limited thermal stress conditions), a substantial reduction in BAT mass via iBATx does not disrupt systemic glucose metabolism, challenging the current dogma that preservation of BAT is obligatory for optimal metabolic function. However, iBATx caused aortic stiffening in lean mice, hence supporting the existence of an interplay between iBAT and aortic stiffness, independent of alterations in glucose homeostasis.

Non-hemodynamic predictors of arterial stiffness after 17 years of follow-up: the Malmö Diet and Cancer study

Background:

Arterial stiffness plays a fundamental role in the development of hypertension and is a risk factor for both cardiovascular disease and mortality. The stiffening that occurs with increasing age has, in numerous cross-sectional studies, been shown to be associated with several cardiovascular risk factors. This observational study aims to characterize the predictive and cross-sectional markers focusing on the non-hemodynamic component of arterial stiffness.

Method:

In all, 2679 men and women from Malmö, Sweden, were examined at baseline during 1991–1994, and again at follow-up during 2007–2012 (mean age 72 years, 38% men). Follow-up examination included measurement of arterial stiffness by carotid–femoral pulse wave velocity (c-fPWV), after a mean period of 17 years. The associations between c-fPWV and risk markers were calculated with multiple linear regression.

Results:

The results indicated that for both sexes, waist circumference (β = 0.17, P < 0.001), fasting glucose (β = 0.13, P < 0.001), Homeostatic Model Assessment – Insulin Resistance (β = 0.10, P < 0.001), triglycerides (β = 0.10, P < 0.001), and high-density lipoprotein cholesterol (β = −0.08, P < 0.001) were all predictors of cfPWV adjusted for mean arterial pressure and heart rate, as well as for classical cardiovascular risk factors and drug treatment. There were no associations between baseline or follow-up low-density lipoprotein cholesterol, smoking, or eGFR and c-fPWV.

Conclusion:

The non-hemodynamic cluster of risk markers and predictors of arterial stiffness in a middle-aged population includes abdominal obesity, hyperglycemia, and dyslipidemia, but not smoking and low-density lipoprotein cholesterol. This pattern existed in both sexes.

Relationship between cardio-ankle vascular index and plasma lipids in hypertension subjects

An increasing of arterial stiffness is the path physiological characteristic of hypertension. Cardio-ankle vascular index (CAVI) is a new index of arterial stiffness. In the present study, we investigated the relationship between CAVI and plasma lipids in hypertension subjects. A total of 542 subjects (male/female 336/206) from the Department of Vascular Medicine were divided into two groups: healthy group (n=402) and hypertension group (n=140). CAVI was measured with VS-1000 apparatus. Our results showed that the levels of CAVI, body mass index (BMI), fast blood glucose (FBG), uric acid (UA) and triglycerides (TGs) were significantly higher in the hypertension group than in the control group (all P<0.01). High-density lipoprotein cholesterol (HDL-C) was significantly lower in the hypertension group than in the control group (P<0.001). CAVI was positively correlated with FBG, UA, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and TG in the entire study group. Negative correlation between CAVI and HDL-C was found in the entire group even after adjusting for age, gender and blood pressure. In addition, there was negative correlation between CAVI and HDL-C in the control group. However, there was negative relational tendency between CAVI and HDL-C in hypertension subjects without significant difference. Multiple linear regression analysis showed that age, BMI, FBG, TG and heart rate were independent associating factors of CAVI in all subjects. Age, FBG and Cr were independent associating factors of CAVI in the hypertension group. Our present study showed that CAVI was significantly higher in hypertension subjects, and metabolic accompaniments might involve the increasing of arterial stiffness in hypertension patients.