Renalase in Children with Glomerular Kidney Diseases

Circadian Blood Pressure Profile in Pediatric Patients with Primary Hypertension

Our study aimed to evaluate factors affecting circadian BP profile and its association with hypertension-mediated organ damage (HMOD) in pediatric patients with primary hypertension (PH). The study included 112 children (14.7 ± 2.1 age, 79 boys, 33 girls) with untreated PH. Non-dipping was defined as a nocturnal drop in systolic or diastolic BP (SBP, DBP) < 10%, and a nocturnal drop >20% was defined as extreme dipping. The nocturnal SBP drop was 10.9 ± 5.9 (%), and the DBP drop was 16.2 ± 8.5 (%). Non-dipping was found in 50 (44.6%) children and extreme dipping in 29 (25.9%) patients. The nocturnal SBP decrease correlated with BMI Z-score (r = −0.242, p = 0.010) and left ventricular mass index (LVMI) (r = −0.395, p = 0.006); diastolic DBP decrease correlated with augmentation index (AIx75HR) (r = 0.367, p = 0.003). Patients with a disturbed blood pressure profile had the highest LVMI (p = 0.049), while extreme dippers had the highest augmentation index (AIx75HR) (p = 0.027). Elevated systolic and diastolic BP dipping were risk factors for positive AIx75HR (OR 1.122 95CI (1.009−1.249) and OR 1.095 95CI (1.017−1.177). We concluded that disturbed circadian BP profile was common in children with PH and should not be considered a marker of secondary hypertension. A disturbed circadian BP profile may be associated with higher body weight. In pediatric patients with PH, non-dipping is associated with increased left ventricular mass, and extreme dipping may be a risk factor for increased arterial stiffness.

NT-proBNP as a Potential Marker of Cardiovascular Damage in Children with Chronic Kidney Disease

Assessing cardiovascular disease (CVD) in children with chronic kidney disease (CKD) is difficult. Great expectations have been associated with biomarkers, including the N-terminal pro-brain natriuretic peptide (NT-proBNP). This study aimed to determine the correlation between NT-proBNP and cardiovascular complications in children with CKD. Serum NT-proBNP, arterial stiffness, common carotid artery intima-media thickness (cIMT), echocardiographic (ECHO) parameters (including tissue Doppler imaging), and biochemical and clinical data were analyzed in 38 pediatric patients with CKD (21 boys, 12.2 ± 4.2 years). Mean NT-proBNP in CKD patients was 1068.1 ± 4630 pg/mL. NT-proBNP above the norm (125 pg/mL) was found in 16 (42.1%) subjects. NT-proBNP correlated with glomerular filtration rate (GFR) (r = -0.423, p = 0.008), and was significantly higher in CKD G5 (glomerular filtration rate grade) patients compared to CKD G2, G3, and G4 children (p = 0.010, p = 0.004, and p = 0.018, respectively). Moreover, NT-proBNP correlated positively with augmentation index (AP/PP: r = 0.451, p = 0.018, P2/P: r = 0.460, p = 0.016), cIMT (r = 0.504, p = 0.020), and E/E' in ECHO (r = 0.400, p = 0.032). In multivariate analysis, logNT-proBNP was the only significant predictor of cIMT Z-score (beta = 0.402, 95CI (0.082-0.721), p = 0.014) and P2/P1 (beta = 0.130, 95CI (0.082-0.721), p = 0.014). Conclusions: NT-proBNP may serve as a possible marker of thickening of the carotid artery wall in pediatric patients with CKD. The final role of NT-proBNP as a biomarker of arterial damage, left ventricular hypertrophy, or cardiac diastolic dysfunction in CKD children needs confirmation in prospective studies.

Serum Sclerostin Is Associated with Peripheral and Central Systolic Blood Pressure in Pediatric Patients with Primary Hypertension

Recent studies showed the significance of the canonical Wnt/beta-catenin pathway and its inhibitor—sclerostin, in the formation of arterial damage, cardiovascular morbidity, and mortality. The study aimed to assess serum sclerostin concentration and its relationship with blood pressure, arterial damage, and calcium-phosphate metabolism in children and adolescents with primary hypertension (PH). Serum sclerostin concentration (pmol/L) was evaluated in 60 pediatric patients with PH and 20 healthy children. In the study group, we also assessed calcium-phosphate metabolism, office peripheral and central blood pressure, 24 h ambulatory blood pressure, and parameters of arterial damage. Serum sclerostin did not differ significantly between patients with PH and the control group (36.6 ± 10.6 vs. 41.0 ± 11.9 (pmol/L), p = 0.119). In the whole study group, sclerostin concentration correlated positively with height Z-score, phosphate, and alkaline phosphatase, and negatively with age, peripheral systolic and mean blood pressure, and central systolic and mean blood pressure. In multivariate analysis, systolic blood pressure (SBP) and height expressed as Z-scores were the significant determinants of serum sclerostin in the studied children: height Z-score (β = 0.224, (95%CI, 0.017–0.430)), SBP Z-score (β = −0.216, (95%CI, −0.417 to −0.016)). In conclusion, our results suggest a significant association between sclerostin and blood pressure in the pediatric population.

Circulating calcification inhibitors are associated with arterial damage in pediatric patients with primary hypertension

BACKGROUND

Circulating calcification inhibitors: fetuin A (FA) and osteoprotegerin (OPG) together with soluble ligand of receptor activator of nuclear factor kappa-B (sRANKL) have been linked to vascular calcifications and arterial damage. This study aimed to evaluate relationships between FA, OPG, sRANKL, and arterial damage in children with primary hypertension (PH).

METHODS

In this cross-sectional single-center study, calcification inhibitors (FA, OPG, sRANKL) levels were measured in blood samples of 60 children with PH (median age 15.8, IQR: [14.5-16.8] years) and 20 age-matched healthy volunteers. In each participant, peripheral and central blood pressure evaluation (BP) and ambulatory BP monitoring (ABPM) were performed. Arterial damage was measured using common carotid artery intima media thickness (cIMT), pulse wave velocity (PWV), augmentation index (AIx75HR), and local arterial stiffness (ECHO-tracking-ET) analysis.

RESULTS

Children with PH had significantly higher peripheral and central BP, BP in ABPM, thicker cIMT, higher PWV, and AIx75HR. FA was significantly lower in patients with PH compared to healthy peers without differences in OPG, sRANKL, and OPG/sRANKL and OPG/FA ratios. In children with PH, FA level correlated negatively with cIMT Z-score and ET AIx; sRANKL level correlated negatively with ABPM systolic blood pressure (SBP), SBP load, diastolic BP load, and AIx75HR; OPG/sRANKL ratio correlated positively with SBP load, while OPG/FA ratio correlated positively with ET AIx. In multivariate analysis, FA was a significant determinant of cIMT (mm) and cIMT Z-score.

CONCLUSIONS

This study reveals that in children with primary hypertension, arterial damage is related to lower fetuin A concentrations.

Serum Periostin as a Potential Biomarker in Pediatric Patients with Primary Hypertension

Experimental studies suggest that periostin is involved in tissue repair and remodeling. The study aimed to evaluate serum periostin concentration as potential biomarker in pediatric patients with primary hypertension (PH). We measured serum periostin, blood pressure, arterial damage, biochemical, and clinical data in 50 children with PH and 20 age-matched healthy controls. In univariate analysis, children with PH had significantly lower serum periostin compared to healthy peers (35.42 ± 10.43 vs. 42.16 ± 12.82 [ng/mL], p = 0.038). In the entire group of 70 children serum periostin concentration correlated negatively with peripheral, central, and ambulatory blood pressure, as well as with aortic pulse wave velocity (aPWV). In multivariate analysis, periostin level significantly correlated with age (β = -0.614, [95% confidence interval (CI), -0.831--0.398]), uric acid (β = 0.328, [95%CI, 0.124-0.533]), body mass index (BMI) Z-score (β = -0.293, [95%CI, -0.492--0.095]), high-density lipoprotein (HDL)-cholesterol (β = 0.235, [95%CI, 0.054-0.416]), and triglycerides (β = -0.198, [95%CI, -0.394--0.002]). Neither the presence of hypertension nor blood pressure and aPWV influenced periostin level. To conclude, the role of serum periostin as a biomarker of elevated blood pressure and arterial damage in pediatric patients with primary hypertension is yet to be unmasked. Age, body mass index, uric acid, and lipid concentrations are key factors influencing periostin level in pediatric patients.

Asymmetric dimethylarginine is not a marker of arterial damage in children with glomerular kidney diseases

Introduction

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, correlates with cardiovascular risk especially in patients with chronic kidney disease. The aim of our study was to establish significance of ADMA as a biomarker of arterial damage in children with glomerulopathies.

Material and methods

In 80 children with glomerulopathies (mean age, 11.33 ±4.25 years; 42 with idiopathic nephrotic syndrome [INS], 38 with IgA or Henoch-Schoenlein nephropathy [IgAN/HSN]), we analyzed serum ADMA [nmol/ml], peripheral and central blood pressure, arterial stiffness (augmentation index – AIx75HR, pulse wave velocity – PWV), common carotid artery intima media thickness (cIMT), and selected clinical and biochemical parameters.

Results

In the study group, mean ADMA concentration was 1.66 ±1.19 [nmol/ml] and did not differ between INS and IgAN/HSN patients. We found no significant correlations between concentration of ADMA, cIMT [mm]/Z-score, PWV [m/s]/Z-score, and AIx75HR [%] in the whole group and in INS and IgAN/HSN patients. In the whole group of 80 children, ADMA correlated (p < 0.05) with BMI Z-score (r = –0.24), uric acid (r = –0.23), HDL-cholesterol (r = –0.25), and central mean arterial pressure (r = –0.25), in children with INS also with total protein (r = 0.37), albumin (r = 0.36), and total cholesterol (r = –0.40, p = 0.028). In multivariate analysis, serum albumin was the strongest determinant of ADMA in the whole group (β = 0.536, 95% CI: 0.013-1.060, p = 0.045).

Conclusions

1. In children with glomerulonephritis, measurement of asymmetric dimethylarginine cannot replace well established and validated methods of assessment of subclinical arterial damage. 2. In children with glomerular kidney diseases, ADMA concentration is related primarily to serum albumin concentration.

Renalase in children with chronic kidney disease

Background: Renalase is kidney-derived molecule initially considered as catecholamine-inactivating enzyme. However, recent studies suggest that renalase exerts potent cardio- and nephroprotective actions, not related to its enzymatic activity. Purpose: To assess renalase level in children with chronic kidney disease (CKD). Material and methods: Serum renalase, BMI, arterial stiffness, peripheral and central blood pressure, intima-media thickness (IMT), medications, and biochemical parameters were analyzed in 38 children with CKD (12.23 ± 4.19 years) (stage G2-5). Control group consisted of 38 healthy children. Results: In the study group, GFR was 25.74 ± 8.94 mL/min/1.73 m²; 6 children were dialyzed; 26 had arterial hypertension. Renalase level was higher in the study group compared to control group (p < 0.001). In CKD children renalase correlated (p < 0.05) with BMI Z-score (r = -0.36), alfacalcidol dose (r = 0.41), GFR (r = -0.69), hemoglobin (r = -0.48), total cholesterol (r = 0.35), LDL-cholesterol (r = 0.36), triglycerides (r = 0.52), phosphate (r = 0.35), calcium-phosphorus product (r = 0.35), parathormone (r = 0.58), and pulse wave velocity Z-score (r = 0.42). In multivariate analysis GFR (β = -0.63, p < 0.001), triglycerides (β = 0.59, p = 0.002), and alfacalcidol dose (β = -0.49, p = 0.010) were determinants of renalase. Conclusions: In children with CKD there is a strong correlation between renalase level and CKD stage. Furthermore, in these patients renalase does not correlate with blood pressure but may be a marker of arterial stiffness.