Albuminuria as a marker of arterial stiffness in chronic kidney disease patients

Early Vascular Aging in Children With Tuberous Sclerosis Complex

Objectives: Experimental data indicate that activating mutations in the mTOR (mammalian target of rapamycin) pathway may lead to abnormal arterial wall structure. Vascular anomalies like arterial stenoses are reported in pediatric patients with tuberous sclerosis complex (TSC). In addition, large renal lesions (angiomyolipoma-AML and cysts) are risk factors for arterial hypertension in adult patients with TSC. This study aimed to assess blood pressure, including central blood pressure and arterial damage (early vascular aging-EVA) in children with TSC. Materials and Methods: In a group of 33 pediatric patients with TSC (11.13 ± 4.03 years, 15 boys, 18 girls), we evaluated peripheral and central office blood pressure, 24-h ambulatory blood pressure, and arterial damage: aortic pulse wave velocity (aPWV) [m/s], [Z-score], augmentation index (AIx75HR [%]), common carotid artery intima-media thickness (cIMT) [mm], [Z-score], stiffness of common carotid artery (E-tracking), renal lesions in magnetic resonance and ultrasonography, and selected biochemical parameters. The control group consisted of 33 healthy children (11.23 ± 3.28 years, 15 boys, 18 girls). Results: In TSC group 7 (21.2%) children had arterial hypertension, 27 (81.8%) children had renal angiomyolipomas, 26 (78.8%)-renal cysts, and 4 (12.1%) patients were treated with mTOR inhibitors (2 patients with everolimus and 2 patients with sirolimus) at the moment of evaluation. Children with TSC had higher central systolic blood pressure (AoSBP) (98.63 ± 9.65 vs. 90.45 ± 6.87 [mm Hg], p < 0.001), cIMT (0.42 ± 0.05 vs. 0.39 ± 0.03 [mm], p = 0.011), cIMT Z-score (0.81 ± 1.21 vs. 0.16 ± 0.57, p = 0.007), aPWV (4.78 ± 0.81 vs. 4.25 ± 0.56 [m/s], p = 0.003) and aPWV Z-score (-0.14 ± 1.15 vs. -0.96 ± 0.87, p = 0.002) compared to healthy children, without differences in AIx75HR (8.71 ± 15.90 vs. 5.24 ± 11.12 [%], p = 0.319) and stiffness of common carotid artery. In children with TSC AoSBP correlated positively with serum cystatin C concentration (r = 0.377, p = 0.030) and with maximum diameter of renal cyst (R = 0.419, p = 0.033); mean arterial pressure (MAP) 24 h Z-score correlated with serum cystatin C concentration (R = 0.433, p = 0.013); and aPWV Z-score with daily urinary albumin loss [mg/24 h] (R = 0.412, p = 0.029). Conclusions: Children with tuberous sclerosis complex are at risk of elevated central blood pressure and early vascular aging. In children with TSC, blood pressure and arterial stiffness are related to renal involvement.

Effects of different fatty acids on BRL3A rat liver cell damage

To evaluate the effects of fatty acids on endoplasmic reticulum (ER) stress, oxidative stress, and lipid damage. We treated BRL3A rat liver cells with, linoleic (LA), linolenic, oleic (OA), palmitic (PA), palmitoleic (POA), or stearic (SA) acid for 12 hr. The characteristics of cell lipid deposition, oxidative stress indexes, ER stress markers, nuclear factor κB p65 (NF-κB p65), lipid synthesis and transport regulators, and cholesterol metabolism regulators were analyzed. Endoplasmic chaperones like glucose-regulated protein 78, CCAAT-enhancer-binding protein, NF-κB p65, hydrogen peroxide, and malonaldehyde in PA- and SA-treated cells were significantly higher than in other treated cells. Deposition of fatty acids especially LA and POA were significantly increased than in other treated cells. De novo lipogenesis regulators sterol regulatory element-binding protein 1c, fatty acid synthase, and acetyl-coenzyme A carboxylase 1 (ACC1) expression were significantly increased in all fatty acid stimulation groups, and PA- and SA-treated cells showed lower p-ACC1 expression and higher scd1 expression than other fatty acid groups. Very low-density lipoprotein synthesis and apolipoprotein B100 expression in free fatty acids treated cells were significantly lower than control. PA, SA, OA, and POA had shown significantly increased cholesterol synthesis than other treated cells. PA and SA showed the lower synthesis of cytochrome P7A1 and total bile acids than other fatty acids treated cells. Excess of saturated fatty acids led to severe ER and oxidative stress. Excess unsaturated fatty acids led to increased lipid deposition in cultured hepatocytes. A balanced fatty acid intake is needed to maintain lipid homeostasis.

Relationship between arterial stiffness and chronic kidney disease in patients with primary hypertension

To investigate the association of noninvasive indices of arterial stiffness with chronic kidney disease (CKD) in patients with primary hypertension, 547 (mean age 60 years, 63% males) hypertensive hospital inpatients were recruited, comprising 337 hypertensives without CKD and 210 hypertensives with CKD. Noninvasive arterial stiffness indices were obtained, including central arterial haemodynamics derived from the radial artery waveform using SphygmoCor V8.0 system, carotid-femoral pulse wave velocity (cfPWV), large and small artery elasticity indices (C1, C2 respectively). Intima-media thickness (IMT) was evaluated by ultrasonography. The diagnosis of CKD was assessed by the estimated glomerular filtration rate (eGFR) or urinary albumin creatinine ratio (ACR). Compared with hypertension without CKD, hypertensive patients with CKD were older, had higher central systolic blood pressure, cfPWV, and IMT (all P < 0.01). With decreasing eGFR, cfPWV and augmentation index adjusted to heart rate of 75 bpm increased progressively whereas C2 decreased (P < 0.05) in subjects with CKD. In the overall population, cfPWV showed a significant trend of a negative association with eGFR (P = 0.04) after adjusting for age, gender, and brachial systolic blood pressure. Multiple logistic analysis showed that 1 SD (3 m/s) increase in cfPWV entailed a 1.35 (95% Cl: 1.018-1.790) times higher likelihood of the presence of CKD even after adjustment for confounding factors. The association of arterial stiffness and CKD suggests that cfPWV may be a potential hemodynamic index to evaluate cardiovascular risk in CKD patients with primary hypertension.

County-level air quality and the prevalence of diagnosed chronic kidney disease in the US Medicare population

BACKGROUND

Considerable geographic variation exists in the prevalence of chronic kidney disease across the United States. While some of this variability can be explained by differences in patient-level risk factors, substantial variability still exists. We hypothesize this may be due to understudied environmental exposures such as air pollution.

METHODS

Using data on 1.1 million persons from the 2010 5% Medicare sample and Environmental Protection Agency air-quality measures, we examined the association between county-level particulate matter ≤2.5 μm (PM2.5) and the prevalence of diagnosed CKD, based on claims. Modified Poisson regression was used to estimate associations (prevalence ratios [PR]) between county PM2.5 concentration and individual-level diagnosis of CKD, adjusting for age, sex, race/ethnicity, hypertension, diabetes, and urban/rural status.

RESULTS

Prevalence of diagnosed CKD ranged from 0% to 60% by county (median = 16%). As a continuous variable, PM2.5 concentration shows adjusted PR of diagnosed CKD = 1.03 (95% CI: 1.02-1.05; p<0.001) for an increase of 4 μg/m3 in PM2.5. Investigation by quartiles shows an elevated prevalence of diagnosed CKD for mean PM2.5 levels ≥14 μg/m3 (highest quartile: PR = 1.05, 95% CI: 1.03-1.07), which is consistent with current ambient air quality standard of 12 μg/m3, but much lower than the level typically considered healthy for sensitive groups (~40 μg/m3).

CONCLUSION

A positive association was observed between county-level PM2.5 concentration and diagnosed CKD. The reliance on CKD diagnostic codes likely identified associations with the most severe CKD cases. These results can be strengthened by exploring laboratory-based diagnosis of CKD, individual measures of exposure to multiple pollutants, and more control of confounding.

Central wave reflection is associated with peripheral arterial resistance in addition to arterial stiffness in subjects without antihypertensive medication

Background

Augmentation index, a marker of central wave reflection, is influenced by age, sex, height, blood pressure, heart rate, and arterial stiffness. However, the detailed haemodynamic determinants of augmentation index, and their relations, remain uncertain. We examined the association of augmentation index with vascular resistance and other haemodynamic and non-haemodynamic factors.

Methods

Background information, laboratory values, and haemodynamics of 488 subjects (239 men, 249 women) without antihypertensive medication were obtained. Indices of central wave reflection, systemic vascular resistance, cardiac function, and pulse wave velocity were measured using continuous radial pulse wave analysis and whole-body impedance cardiography.

Results

In a regression model including only haemodynamic variables, augmentation index in males and female subjects, respectively, was associated with systemic vascular resistance (β = 0.425, β = 0.336), pulse wave velocity (β = 0.409, β = 0.400) (P < 0.001 for all), stroke volume (β = 0.256, β = 0.278) (P = 0.001 for both) and heart rate (β = −0.150, β = −0.156) (P = 0.049 and P = 0.036). When age, height, weight, smoking habits, and laboratory values were included in the regression model, the most significant explanatory variables for augmentation index in males and females, respectively, were age (β = 0.577, β = 0.557) and systemic vascular resistance (β = 0.437, β = 0.295) (P < 0.001 for all). In the final regression model, pulse wave velocity was not a significant explanatory variable for augmentation index, probably due to the high correlation of this variable with age (Spearman’s correlation ≥0.617).

Conclusion

Augmentation index is strongly associated with systemic vascular resistance in addition to arterial stiffness.

Trial registration

ClinicalTrials.gov, NCT01742702.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0303-6) contains supplementary material, which is available to authorized users.