Inflammation and oxidative stress are associated with the prevalence of high aankle-brachial index in metabolic syndrome patients without chronic renal failure

Abnormal Calcium Metabolism Mediated Increased Risk of Cardiovascular Events Estimated by High Ankle-Brachial Index in Patients on Peritoneal Dialysis

Cardiovascular disease (CVD) is the leading cause of death in peritoneal dialysis (PD) patients. But the relationship between regular PD and the risk of major adverse cardiovascular events (MACE) remains controversial. The possible risk factors are not fully elucidated. This study aims to investigate the possible factors affecting the risk of MACE estimated by high ankle-brachial index (ABI) in PD patients. A total of 243 patients were enrolled and divided into chronic kidney diseases (CKD) stage 1, non-dialyzed CKD stages 2–5, and PD groups. The prevalence of high ABI, indicating increased MACE, was elevated with CKD progression but not further increased in PD patients. Systolic blood pressure was closely correlated with high ABI in non-dialyzed CKD patients (β = 0.059, P = 0.001). But in PD patients, serum calcium had a crucial effect on high ABI (β = −9.853, P < 0.001). Additionally, PD patients with high ABI tended to dialyze inadequately (Kt/V <1.7) compared to those with normal ABI (29.0 vs. 13.3%, P = 0.031). Further mediation analysis revealed that ~86.2% of the relationship between Kt/V and high ABI was mediated by serum calcium in PD patients (mediation effect = 86.2%, ab = −0.220, 95% CI: −0.381 to −0.059, P = 0.008), especially in those starting PD before 55 years of age and with normal body mass index. This present study indicated that improvement of PD adequacy by maintaining calcium balance might be a promising method to reduce the risk of MACE estimated by high ABI for PD patients.

Disparity in association of obesity measures with ankle and brachial systolic blood pressures in Europeans and South Asians

Obesity causes increases in brachial systolic-blood-pressures (SBP), risks of type 2 diabetes (T2DM) and cardiovascular diseases (CVD). Brachial and ankle SBPs have differential relationship with T2DM and CVD. Our objective was to study the relationship of obesity measures with brachial and ankle SBPs. A population of 1098 adults (South Asians n = 699; 41.70% male and 58.3% female) were recruited over 5 years from primary care practices in England. Their four limbs SBPs were measured using Doppler machine and body-mass-index (BMI) and waist-to-height-ratio (WHtR) calculated. Linear regressions were performed between SBPs and obesity measures, after adjustments for sex, age, ethnicity, T2DM and CVD. The mean age of all participants was 51.3 (SD = 17.2), European was 57.7 (SD 17.2) and South Asian was 47.8 (SD = 16.1). The left posterior tibial [Beta = 1.179, P = 4.559 × 10⁻¹⁵] and the right posterior tibial SBP [Beta = 1.178, P = 1.114 × 10⁻¹³] most significantly associated with the BMI. In South Asians, although the left brachial [Beta = 25.775, P = 0.032] and right brachial SBP [Beta = 22.792, P = 0.045] were associated to the WHtR, the left posterior tibial SBP [Beta = 39.894, P = 0.023], association was the strongest. For the first time, we have demonstrated that ankle SBPs had significant association with generalised obesity than brachial systolic blood pressures (SBP), irrespective of ethnicity. However, with respect to visceral obesity, the association with ankle SBP was more significant in South Asians compared to Europeans.

IL-18 Mediates Vascular Calcification Induced by High-Fat Diet in Rats With Chronic Renal Failure

Objective: Vascular calcification (VC) is an important predictor of cardiovascular morbidity and mortality in patients with chronic renal failure (CRF). It is well-known that obesity and metabolic syndrome (OB/MS) predicts poor prognosis of CRF patients. However, the influence of OB/MS on VC in CRF patients isn't clear. IL-18 mediates OB/MS-related inflammation, but whether IL-18 is involved in OB/MS -mediated VC in CRF patients hasn't been studied. In this study, it was explored that whether OB/MS caused by high-fat diet (HFD) can affect the level of serum IL-18 and aggravate the degree of VC in CRF rats. Furthermore, it was studied that whether IL-18 induces rat vascular smooth muscle cells (VSMCs) calcification by activating the MAPK pathways. Approach: The rats were randomly assigned to the sham-operated, CRF and CRF + HFD groups. CRF was induced by 5/6 nephrectomy. Serum IL-18 levels and aortic calcification indicators were compared in each group. Primary rat VSMCs calcification were induced by β-glycerophosphate and exposed to IL-18. VSMCs were also treated with MAPK inhibitors. Results: The weight, serum levels of hsCRP, TG and LDL-C in CRF + HFD group were significantly higher than those in sham-operated and CRF groups (p < 0.05). Compared with the sham-operated group, the calcium content and the expression of BMP-2 of aorta in CRF and CRF + HFD groups were significantly increased (p < 0.05). Moreover, the calcium content and the expression of BMP-2 of aorta in CRF + HFD group was significantly higher than those in CRF group (p < 0.05). And the serum IL-18 level was positively correlated with aortic calcium content. It was also found that p38 inhibitor SB203580 can suppress the VSMCs calcification and osteoblast phenotype differentiation induced by IL-18. But the JNK inhibitor SP600125 can't suppress the VSMCs calcification and osteoblast phenotype differentiation induced by IL-18. Conclusions: These findings suggest that obesity-related inflammation induced by high-fat diet could exacerbate VC in CRF rats. Furthermore, serum IL-18 level had a positive correlation with the degree of VC. It is also found that IL-18 promoted osteogenic differentiation and calcification of rat VSMCs via p38 pathway activation.

Association between ankle-brachial index and cognitive function in participants in the PREDIMED-Plus study: cross-sectional assessment

INTRODUCTION AND OBJECTIVES

The ankle-brachial index (ABI) is an indicator of peripheral artery disease (PAD). The aim of this study was to assess the association between PAD, measured with the ABI, and cognitive function in persons with overweight or obesity and metabolic syndrome.

METHODS

Cross-sectional study conducted with baseline data from the PREDIMED-Plus study, which included 4898 participants (after exclusion of those without ABI measurements) aged between 55 and 75 years, and with overweight or obesity and metabolic syndrome. At the baseline assessment, we measured the ABI with a standardized protocol and assessed the presence of other cardiovascular risk factors (eg, diabetes, dyslipidemia, hypertension). Cognitive function was evaluated using several tests validated for the Spanish population (mini-mental state examination [MMSE], phonological and semantic verbal fluency test, WAIS-III working memory index [WMI], parts A and B of the trail making test (TMT), and clock drawing test). Generalized linear models were used to assess the association between the ABI and cognitive function.

RESULTS

Among the participants, 3.4% had PAD defined as ABI ≤ 0.9, and 3.3% had arterial calcification defined as ABI ≥ 1.4. PAD was associated with age, systolic blood pressure and obesity indicators, while arterial calcification was also associated with obesity and diabetes. No significant associations were observed between cognitive function and ABI or PAD.

CONCLUSIONS

In our sample, the presence of PAD increased with age, blood pressure, and obesity. No significant association was observed between ABI, PAD, or cognitive function.

Association between ankle-brachial index and cognitive function in participants in the PREDIMED-Plus study: cross-sectional assessment

INTRODUCTION AND OBJECTIVES

The ankle-brachial index (ABI) is an indicator of peripheral artery disease (PAD). The aim of this study was to assess the association between PAD, measured with the ABI, and cognitive function in persons with overweight or obesity and metabolic syndrome.

METHODS

Cross-sectional study conducted with baseline data from the PREDIMED-Plus study, which included 4898 participants (after exclusion of those without ABI measurements) aged between 55 and 75 years, and with overweight or obesity and metabolic syndrome. At the baseline assessment, we measured the ABI with a standardized protocol and assessed the presence of other cardiovascular risk factors (eg, diabetes, dyslipidemia, hypertension). Cognitive function was evaluated using several tests validated for the Spanish population (mini-mental state examination [MMSE], phonological and semantic verbal fluency test, WAIS-III working memory index [WMI], parts A and B of the trail making test (TMT), and clock drawing test). Generalized linear models were used to assess the association between the ABI and cognitive function.

RESULTS

Among the participants, 3.4% had PAD defined as ABI ≤ 0.9, and 3.3% had arterial calcification defined as ABI ≥ 1.4. PAD was associated with age, systolic blood pressure and obesity indicators, while arterial calcification was also associated with obesity and diabetes. No significant associations were observed between cognitive function and ABI or PAD.

CONCLUSIONS

In our sample, the presence of PAD increased with age, blood pressure, and obesity. No significant association was observed between ABI, PAD, or cognitive function.

Aortic Pulse Wave Velocity, Ankle-Brachial Index, and Malondialdehyde in Older Adults with or without Metabolic Syndrome

Metabolic syndrome is an important health problem associated with both subclinical atherosclerosis and an increased risk of cardiovascular disease and it leads to an elevated total mortality. Aortic pulse wave velocity (aPWV) is widely used for noninvasive assessment of arterial stiffness. Ankle-brachial index (ABI) predicts peripheral arterial disease (PAD) of the lower extremities. In addition, malondialdehyde (MDA) is thought to be involved in the development of arterial stiffness. The present study aimed to: (1) compare aPWV, ABI, and MDA between participants with MetS and those without MetS and (2) investigate the correlation of aPWV and ABI with the components of MetS and MDA. A total of 48 Thai elderly subjects were divided into 2 groups (MetS and non-MetS) according to the parameters set by the International Diabetes Federation (IDF). aPWV and ABI were measured using the VaSera VS-1500 system (Fukuda Denshi Co., Tokyo, Japan). MDA was determined by spectrophotometry. aPWV and MDA were significantly higher in the MetS group compared to the participants in the non-MetS group (9.33 ± 2.72 vs. 7.95 ± 1.37 m/s, p = 0.03, and 0.74 ± 0.71 vs. 0.45 ± 0.20 μmol, p = 0.02, respectively). However, ABI did not differ between the groups. Analysis of the risk factors of aPWV in each group revealed that there were no statistical associations between the components of MetS and MDA and aPWV in both the MetS and the non-MetS groups. A high aPWV is more prevalent among patients with MetS than among those without MetS. Monitoring of aPWV might help to explore potential detection of vascular damage in the elderly.

Aquaporin 1 alleviates acute kidney injury via PI3K-mediated macrophage M2 polarization

BACKGROUND

Lipopolysaccharide (LPS)-induced acute kidney injury (AKI) is associated with an abnormal immune response. Accumulating evidence has demonstrated that aquaporin 1 (AQP1) prevents kidney tissue injury in LPS-induced AKI by mediating immune response. However, the underlying mechanisms remain obscure. Macrophages as immune cells with multiple phenotypes are important mediators in tissue homeostasis and host defense. We propose that macrophage polarization is implicated in AQP1-mediated immune response.

METHODS

Herein we established sepsis-induced AKI model rats through intraperitoneal injection of LPS into Wistar rats to reveal immune mechanism of damage. We also used LPS-induced mouse RAW264.7 cells to elucidate the molecular mechanism of macropage polarization.

RESULTS

Histopathology showed that renal tubular epithelial cells in the model group were swollen, inflammatory exudation was obvious and the inflammatory factors, interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) were increased. Western blotting showed PI3K was upregulated in the model group. Serum creatinine and urea nitrogen increased after LPS injection. Renal AQP1 mRNA is downregulated and serum AQP1 protein increased first and then decreased in LPS-induced AKI rats. M2 macrophage markers (Arg-1, CD206) were increased in repair stage. In addition, treatment of murine macrophages (RAW264.7) with AQP1 siRNA resulted in decreased PI3K activation and M2 polarization, but increased IL-6 and TNF-α. Moreover, inhibiting PI3K with wortmannin imitated the results of AQP1 silencing.

CONCLUSIONS

Macrophage M2 polarization is likely the cellular mechanism underlying the anti-AKI property of AQP1, and PI3K activation is involved in the AQP1-induced M2 phenotype switch.

Apocynin attenuates angiotensin II-induced vascular smooth muscle cells osteogenic switching via suppressing extracellular signal-regulated kinase 1/2

Vascular calcification (VC) is a significant risk factor for cardiovascular morbidity and mortality. We recently reported that apocynin had benefits for preventing cardiovascular diseases. However, whether apocynin could attenuate VC is unknown. Here, we investigated the role of apocynin in VC and its underlying mechanisms. 163 participants with high or normal ankle–brachial index (ABI) were enrolled in this study for analyzing the demographic and biochemical data. In vitro, vascular smooth muscle cells (VSMCs) were exposed to calcification medium containing b-glycerophosphate and angiotensin II (Ang II) for 24 hours. The results showed that serum level of Ang II was significantly increased in patients with high ABI (P<0.05). In cultured VSMCs, Ang II significantly exacerbated osteogenic switching. The expression of osteogenic phenotype markers, including bone morphogenetic protein 2 (BMP2), runt-related transcription factor 2 (Runx2) and osteopontin (OPN), were significantly upregulated, whereas contractile markers expression, including alpha smooth muscle actin (a-SMA) and smooth muscle 22 alpha (SM22a) were simultaneously downregulated. However, these effects were greatly attenuated by apocynin. Apocynin enhanced expression of a-SMA by 5.3%, and reduced expression of BMP2, Runx2, OPN by 3.37%, 0.61% and 3.07%, respectively. Furthermore, extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation was upregulated by Ang II, and this effect was also reversed by apocynin. Intriguingly, pretreatment with U0126, an inhibitor of ERK1/2, had similar effects with apocynin. Apocynin may act as a novel molecular candidate to protect against VSMCs osteogenic switching through suppressing ERK1/2 pathway.

Using brachial-ankle pulse wave velocity to screen for metabolic syndrome in community populations

The aim of this study is to investigate the viability of using brachial-ankle pulse wave velocity (baPWV) as a primary tool to screen metabolic syndrome (MetS), and to explore the risk factors of MetS in community populations. A total of 1914 subjects completed medical examination in Shanghai. BaPWV was significantly associated with the components of MetS. The area under curve (AUC) and its 95% confidence interval (CI) in total group were 62.50% and 60.00%-65.30% with the appropriate cut-off point being 1435 cm/sec. The AUC (95%CI) of three subgroups (40-50 yrs, 50-60 yrs and over 60 yrs group) were 75.30% (67.48%-83.35%), 63.35% (58.96%-67.60%), 55.37% (51.19%-60.01%), respectively. A clear pattern surfaced in the process of investigation: the younger were the subjects group, the better receiver operating characteristic (ROC) efficacy would emerge; and the higher sensitivity was, the better negative predictive value (NPV) would be. Male gender, high baPWV values, elevated uric acid (UA) and excess hypersensitive C reaction protein (hs-CRP) levels were stayed in the two regression models as the independent risk factors for MetS. We conclude that baPWV may serve as a potential screening tool for MetS at the cut-off point of 1435 cm/sec.

Combination of high ankle-brachial index and hard coronary heart disease Framingham Risk Score in predicting the risk of ischemic stroke in general population

Our previous study showed that the patients with more metabolic risk factors had higher risk of high ankle–brachial index (ABI), but the relationship between high ABI and the risk of severe cardiovascular and cerebrovascular diseases is still under debate. This study aims to evaluate this association in the general population. 1486 subjects of South China were recruited in the study. 61 subjects were defined as high ABI group (ABI≥1.3) and 65 subjects were randomly selected as normal ABI group (0.9<ABI<1.3). Biochemical parameters, clinical characteristics and 10-year hard coronary heart disease (HCHD) Framingham Risk Score (FRS) were compared between two groups. The results showed that the 10-year HCHD FRS of high ABI group was significantly higher than normal ABI group (7.87±6.11 vs. 3.98±2.90%, P<0.001). There was a positive correlation between ABI value and HCHD FRS in overweight participants (R = 0.576, P<0.01). The prevalence of ischemic stroke was higher in high ABI group than normal ABI group (21.3% vs. 6.2%, P<0.05), and it was higher in participants with HCHD FRS≥6% than those with HCHD FRS<6% (19.1% vs. 6.9%, P<0.05). Moreover, the prevalence of ischemic stroke was higher in participants with high ABI and HCHD FRS≥6% than those with normal ABI and HCHD FRS<6% (26.7% vs. 4.1%, P<0.05). BMI, hypertension, hsCRP and smoking were proved to be the independent factors and effective predictors for high ABI (P<0.05). In conclusion, high ABI combined with high HCHD FRS should be a potential predictor of ischemic stroke in the general population of South China.