Vitamin D receptor gene polymorphisms in chronic kidney disease Egyptian children: effect on biochemical markers of bone mineral disorders.

INTRODUCTION: The aim of this study was to assess the association between four vitamin D receptor (VDR) single nucleotide polymorphisms BsmI (rs1544410), ApaI (rs7975232), FokI (rs2228570) and TaqI (rs731236) and the susceptibility to chronic kidney disease (CKD) in Egyptian children and to evaluate their association with mineral status in these patients. MATERIAL AND METHODS: The current study included 305 patients with CKD and 100 apparently healthy children. We measured the serum vitamin D (VD), para-thyroid hormone (PTH) level and fibroblast growth factor 23 (FGF-23) levels by ELISA method. The genotyping of the four VDR gene variants was carried out by PCR-RFLP technique. RESULTS: The TaqI AG & the BsmI TT genotypes were associated with a significantly higher risk of CKD. The expression of 25-OH D serum level was decreased in patients with TaqI GG & AG genotypes groups and in patients with BsmI TT genotype group The expression of PTH serum level was increased in patients with BsmI CT genotype group. The expression of FGF-23 serum level was increased in patients with Taq1 AG genotype group. We found 3 specific haplotypes; AGCA, AGCC and GGCA for healthy controls. CONCLUSIONS: Our study showed an association between VDR TaqI, BsmI polymorphisms and the susceptibility to CKD. The existence of VDR vari-ants affected the protein expression of VD, FGF-23 and PTH. The AGCA, AGCC and GGCA haplotypes were considered as protec-tive factors against the development of renal nephropathy in our population.

Genetic polymorphisms in CLDN14 (rs219780) and ALP (rs1256328) genes are associated with risk of nephrolithiasis in Egyptian children.

OBJECTIVE: Nephrolithiasis results from metabolic and anatomic abnormalities together with genetic factors. Claudin 14 (CLDN14) is a protein that regulates the passage of small solutes through the kidneys. Alkaline phosphatase (ALPL) hydrolyzes the pyrophosphate to free phosphate, proposing its enabling role in nephrolithiasis development. Solute carrier family 13 member 2 (SLC13A2) encodes Na+-Pi cotransporter 2a, which is responsible for the renal absorption of phosphate. We aimed to detect the association between CLDN14, ALPL, and SLC13A2 genetic variants and susceptibility to nephrolithiasis in the Egyptian pediatric population. MATERIAL AND METHODS: We enrolled 204 consecutive pediatric patients with nephrolithiasis, and 126 normal individuals served as controls. Real-time polymerase chain reaction analysis of CLDN14 rs219780, ALPL rs1256328, and SLC34A1 rs11746443 single-nucleotide polymorphisms (SNPs) was performed. RESULTS: We found that individuals carrying the T allele of CLDN14 rs219780 and ALPL rs1256328 SNPs had a significantly higher risk of nephrolithiasis than the controls (p=0.001 and 0.001, respectively). Genetic association analyses identified that CLDN14 rs219780 and ALPL rs1256328SNPs were significantly associated with the nephrolithiasis status (odds ratio [OR] =4.51; 95% confidence interval [CI]=2.758-7.374; p=0.001 and OR=6.088; 95% CI=3.651-10.152; p=0.001, respectively). The sequence variant ALPL rs1256328 T allele had a significant correlation with the increased serum alkaline phosphatase levels in children with nephrolithiasis (p=0.02). No significant association was found between SLC34A1 rs11746443 SNP and the risk of nephrolithiasis (p=0.5). CONCLUSION: CLDN14 rs219780 and ALPL rs1256328 SNPs might raise the risk of nephrolithiasis in Egyptian children, and might be used as genetic markers in these patients.

Left Ventricular Myocardial Deformations in Hemodialysis Children by Speckle Tracking Echocardiography.

BACKGROUND: Cardiac systolic dysfunction was potentially found in adult patients with end-stage renal disease (ESRD) who have preserved left ventricular ejection fraction (EF%). In children with ESRD, little data are available on early changes in myocardial function. This study aimed to detect the early changes in myocardial mechanics in pediatric patients with ESRD using speckle tracking echocardiography (STE). METHODS: Thirty ESRD children receiving hemodialysis (HD) and30 age-matched controls were prospectively studied. Patients underwent echocardiographic studies before and after HD. Left ventricular longitudinal strain (LS), circumferential strain (CS), and radial strain (RS) myocardial deformation parameters (strain, strain rate) were evaluated by STE. RESULTS: The LS was significantly reduced in pre-HD and post-HD patients compared with controls (P = .000). Controls showed the highest global longitudinal strain. The RS measurements did not differ significantly among the studied groups except for the inferior segment that is significantly reduced after HD compared with controls (P < .05). The CS was significantly reduced in pre-HD and post-HD patients compared with controls at the lateral and posterior segments (P = .035 and P = .013, respectively). CONCLUSION: Speckle-tracking echocardiography might detect early changes in myocardial mechanics in children with ESRD with preserved EF%.

Klotho G-395A gene polymorphism: impact on progression of end-stage renal disease and development of cardiovascular complications in children on dialysis.

BACKGROUND: Klotho G-395-A gene polymorphism may impact children with end-stage renal disease (ESRD). We investigated the relevance of Klotho G-395-A on ESRD development and progression, and its relationship with evolution of cardiovascular complications in pediatric dialysis patients. METHODS: Fifty-five children with chronic kidney disease (CKD) and seventy healthy children were genotyped for Klotho G-395A. RESULTS: Incidence of GA/AA genotypes and A allele were higher in ESRD patients compared with controls (54.5 vs. 7.1%, P < 0.001; 30.9 vs. 13.6%, P = 0.001, respectively). Also, children with GA/AA genotypes were 15.6 times more likely to develop ESRD than with GG genotype (95% CI 5.4-44.7, P < 0.001). A allele carriers have 2.8 times higher risk of developing ESRD than those with G allele (95% CI 1.5-5.35, P = 0.001). Also, the A allele could be considered a predictor of cardiovascular disease (CVD), as carriers have 161 times higher risk of cardiovascular complications than non-carriers (95% CI 21-1233, P < 0.001). All ESRD patients with CVD presented with left ventricular hypertrophy (LVH) and the frequency of A allele was significantly higher among ESRD children with LVH, whereas G allele frequency was significantly higher among ESRD children without LVH. CONCLUSIONS: The A allele of the G-395A Klotho gene polymorphism shows a significantly higher frequency among children with CKD and those with CVD and LVH. This mutant allele could be used as a risk marker for the development of ESRD as well as a predictor of CVD in these children.

Left ventricular dysfunction by conventional and tissue Doppler echocardiography in pediatric hemodialysis patients: relation with plasma brain natriuretic peptide levels.

INTRODUCTION: Tissue Doppler imaging (TDI) is a relatively new echocardiography method in children with chronic kidney disease (CKD). The aims of this study were to evaluate left ventricular (LV) diastolic function in pediatric CKD patients using conventional pulsed-wave Doppler echocardiography (cPWD) and TDI methods and correlate them with BNP levels. MATERIAL AND METHODS: Thirty children on regular hemodialysis (HD) were included. Left ventricular systolic and diastolic indices and BNP levels were measured immediately before and after HD. RESULTS: After HD, LV and left atrium diameters were significantly decreased (p < 0.001 and p < 0.001, respectively). Transmitral E velocity and E/A ratio decreased (p < 0.001 and p < 0.001, respectively). Also, there were significant decreases in the early diastolic velocity E' of LV wall, septal wall, and anterior wall (p = 0.001, p = 0.004 and p < 0.001, respectively). Mean E/E' ratio and ratios of septal and lateral walls were decreased significantly (p = 0.004, p = 0.002 and p = 0.017, respectively). BNP levels decreased significantly during HD when comparing concentrations before and after HD (p < 0.001). BNP strongly correlated with LV diastolic function indices (before HD: mean E/E' (r = 0.401, p = 0.028), lateral E/E" (r = 0.291, p = 0.025), septal E'(r = -0.398, p = 0.029), lateral wall E' (r = -0.452, p = 0.012) and mean E' (r = -0.469, p = 0.009), after HD: mean E/E' (r = 0.38, p = 0.038) and lateral E/E" (r = 0.474, p = 0.008) and lateral wall E' (r = -0.270, p = 0.037)). CONCLUSIONS: The cPWD and TDI-derived LV indices are influenced by HD. The diagnostic utility of BNP in the presence of deteriorating renal function may be compromised to some extent.

Association of ficolin-2 (FCN2) functional polymorphisms and protein levels with rheumatic fever and rheumatic heart disease: relationship with cardiac function.

INTRODUCTION: A role for ficolin (FCN) 2 gene polymorphisms in the pathogenesis of recurrent severe streptococcal infections and rheumatic carditis has been suggested. The aim of the study was to evaluate a possible relationship between single nucleotide polymorphisms located at positions -602 and -4 of the FCN2 gene and FCN2 serum levels and risk of development of rheumatic fever (RF) and rheumatic heart disease (RHD). MATERIAL AND METHODS: Seventy-seven Caucasian Egyptian patients with RF were recruited with a control group of 43 healthy subjects. DNA was extracted for analysis of the FCN2 gene at positions -602 and -4 and serum protein level was measured by ELISA. RESULTS: FCN2 AA genotype at the -4 position was more frequently observed in RF and RHD patients, as compared to healthy subjects (p = 0.005 and p = 0.013, respectively); furthermore, the A allele was identified as a possible risk factor for the development of RF (p = 0.023, OR = 1.852, 95% CI: 1.085-3.159). The haplotype -602/-4 G/A, which was associated with low median levels of L-ficolin, was observed more frequently in the RF group when compared to the healthy subjects (74/162, 48.1% vs. 29/420, 33.7%, OR = 1.834, 95% CI: 1.034-3.252, p = 0.038). Low serum ficolin-2 level was associated with ESV and EDV increases. FCN 2 level was significantly lower with AA genotypes than GG+AG genotypes of the -4 position (56.68 ±17.90 vs. 66.05 ±18.79, p = 0.008). CONCLUSIONS: Polymorphisms linked to low levels of L-ficolin may render an individual at risk of recurrent and/or severe streptococcal infection. The -4 AA genotype and -602/-4 G/A haplotype are possible risk factors for the development of carditis.

FcγRIIa defunctioning polymorphism in paediatric patients with renal allograft.

INTRODUCTION: Fc gamma receptor (FcγR) IIa is considered the most widely distributed of the three classes of Fc receptors, and it expresses an allelic polymorphism. This type of polymorphism may modify the immune response and may be an important factor for some diseases. The aim of the study reported herein was to evaluate the association between the FcγRIIa polymorphism and susceptibility to both end-stage renal disease (ESRD) and acute kidney graft rejection (AR) in children who have undergone renal transplantation. MATERIAL AND METHODS: The study evaluated 70 children who had undergone transplantation and 60 healthy subjects. AR was observed in 25 children. RESULTS: FcγRIIa genotypes and alleles were significantly different between transplantation patients and the control group. The assessment for FcγR of the groups in which AR was present showed that there was only a risk of having an acute rejection in homozygous genotype RR. CONCLUSIONS: FcγRIIa RR genotype and allele frequency was increased in paediatric renal transplant recipients. The present findings showed that FcγRIIa genotype may be related to ESRD disease susceptibility, and FcγRIIa polymorphisms seemed to affect AR.

Matrix Metalloproteinase (MMP)-9 Levels in Children on Hemodialysis: Association with MMP-9 C-1562T Gene Polymorphism and Vitamin D Levels.

BACKGROUND AND OBJECTIVES: Data concerning the concentration of matrix metalloproteinase-9 (MMP-9) and its functional polymorphisms in chronic kidney diseases (CKD) are conflicting. The present study aimed to evaluate the levels of MMP-9in children with end stage renal diseases (ESRD) on hemodialysis (HD) and to explore its association with MMP-9 polymorphism and vitamin D levels as an important risk factors for cardiovascular diseases (CVD). METHODS: We studied 55 children with ESRD on hemodialysis and 18 healthy children served as controls. MMP-9 and vitamin D levels were measured by ELISA in serum of all patients and controls. Genotypes for MMP-9 polymorphism(C-1562T) were determined by RFLP for only 28 of the patients and all the controls. RESULTS: There were insignificantly reduced MMP-9levels of patients vs. controls, however, there was significant increase in MMP-9 levels associated with CC genotypes for(C-1562T) polymorphism compared with CT genotype (p=0.01). We found that at MMP-9 base position-1562, the frequencies of the genotypes CC and CT in Children on HD were 71.4% and 28.6% respectively while all our controls were of the CC genotype. The alleles frequencies of C and T in patients were 85.7% and 14.29% as compared to 100% and 0%, respectively in the controls. Significant decrease in vitamin D was observed in children on HD versus that in controls (p=0.008). Serum MMP9 levels and age were variables that were independently associated with CVD. CONCLUSIONS: MMP9 genetic polymorphism (C-1562T) affects MMP9alterations in ESRD children on HD and vitamin D deficiency is common in our HD pediatric patients who require attention in accordance with current practice guidelines. They probably require supplementation with higher doses of cholecalciferol.

Fas/Fas Ligand pathways gene polymorphisms in pediatric renal allograft rejection.

BACKGROUND: An essential milestone in pediatric transplantation is to find noninvasive biomarkers to monitor acute rejection (AR). In this retrospective (Case-control) study, we examined the role of Fas -670A/G and Fas Ligand (FasL) -843C/T gene polymorphisms in allograft nephropathy in pediatric renal transplant recipients. METHODS: In 47 pediatric kidney transplant recipients and 20 healthy controls, Fas -670A/G and FasL -843C/T gene polymorphisms as well as serum soluble Fas Ligand level (sFasL) were measured. RESULTS: Serum sFasL levels were significantly higher in transplant recipients children than that in controls (548.25±298.64pg/ml vs 143.17±44.55pg/ml, p=0.0001). There was no significant difference between patients with AR and those without AR in regards to serum sFasL levels (567.70±279.87pg/ml vs 507.85±342.80pg/ml, p=0.56). Fas -670A/G genotypes or alleles were not significantly different between controls and transplant recipients and among transplant recipients with and without AR. (P>0.05 for all). FasL -843C/T genotypes were not different between transplant recipients and controls and among transplant recipients with and without AR (P>0.05 for all). However, Frequency of C allele in transplant patients was significantly higher than that in the control group (44.68% vs 25%, P=0.03). FasL -843C/T alleles were significantly different between patients with and without AR (P=0.03). The percentages of C allele were higher in children with AR (58.82% vs 36.67%). We found that serum FasL and serum creatinine were variables that were independently associated with AR. CONCLUSION: This study suggests that FasL gene polymorphisms in peripheral blood might be accurate in detecting cellular AR.

Coagulation, thrombophilia and patency of arteriovenous fistula in children undergoing haemodialysis compared with healthy volunteers: a prospective analysis.

UNLABELLED: This study aimed to assess whether markers of coagulation, fibrinolysis or thrombophilia are increased in children on haemodialysis compared with controls and whether measurement of any of these factors could help to identify patients at an increased risk of arteriovenous fistula (AVF) occlusion. Blood samples were taken from 55 children immediately before a session of haemodialysis and from 20 healthy volunteers. Thrombin-antithrombin (TAT), D-dimer, plasmin-antiplasmin (PAP) and anticardiolipin immunoglobulin G (ACA-Ig G) were measured by ELISA. Factor V Leiden mutation (G1691A) was determined by gene polymorphism [restriction fragment length polymorphism (RFLP)]. Determination of the patency of the AVF was prospectively followed up for a minimum of 4 years or until the AVF was nonfunctioning. Fifty-five patients were studied with a median follow-up of 659 days (range 30-1670 days). A significant increase was found in the levels of D-dimer, PAP and ACA-Ig G in haemodialysis patients with thrombosed and nonthrombosed native AVFs vs. CONTROLS: There was a significant difference between both chronic haemodialysis patients with thrombosed and nonthrombosed native AVF with regard to ACA-IgG levels. At 1 year follow-up, primary patency was 61.4% (27 patients). In multivariate analysis, D-dimer was inversely associated with secondary patency.Thrombophilia may predispose children with end stage renal disease to access failure. The promising finding is that in children on haemodialysis, D-dimer levels were increased and inversely correlated with secondary patency. Further evaluation is required into the possible role of D-dimer as a biomarker of AVF occlusion.

Usefulness of serum procalcitonin as a diagnostic biomarker of infection in children with chronic kidney disease.

INTRODUCTION: Serum procalcitonin (PCT) levels are known to be low in healthy individuals in healthy subjects but are increased in patients with a severe bacterial infection. It has not been extensively studied in children with chronic kidney disease (CKD), treated either with hemodialysis (HD) or with renal transplantation. MATERIAL AND METHODS: During a 6-month period, blood samples were taken from 102 (55 HD children and 47 renal transplant recipients) children with a strong clinical suspicion of infection. Procalcitonin levels were measured by ELISA. RESULTS: Thirty-four/102 cases had proven infections as defined previously. Children with proven infections had a significantly higher PCT (0.920 ±0.24 ng/ml) than those without (0.456 ±0.53 ng/ml), p = 0.04. The ideal cutoff value derived for serum PCT was 0.5 ng/ml. This threshold value established a sensitivity of 94.1% and a specificity of 87.9%. CONCLUSIONS: This study indicates that significantly increased PCT concentration is a promising predictor of systemic bacterial infection in children with CKD, with good sensitivity and specificity. This study proposes that serum PCT is a convenient index of infection in CKD children at a cutoff value of 0.5 ng/ml.

Lymphocyte Activation Markers in Pediatric Kidney Transplant Recipients.

BACKGROUND AND OBJECTIVES: The role of CD4+CD25+ T regulatory cells (Tregs) in immune tolerance in experimental transplantation is very important but the clinical significance of circulating Tregs in the peripheral blood is undetermined. We evaluated the association between the frequency of T cell activation markers CD25 and CD71 and clinical parameters that may affect the level of these T cell markers. METHODS: In 47peditric kidney transplant (KT) recipients and 20 healthy controls, the frequency of T cell activation markers, CD25 and CD71 was measured with flow cytometry after transplantation. Two clinical protocols of induction immunosuppression were used: (1) anti-thymocyte globulin (THYMO) group (n =29) and Basiliximab (BSX) group (n=10). RESULTS: The percentage of circulating CD25 after KT was significantly lower than that in the controls. There is no significant difference between KT and the controls s regard to circulating CD71. The percentage of CD25 was significantly increased in children with acute rejection compared with those without acute rejection. Calcineurin inhibitors (CNIs) decreased the frequency of CD25 but mammalian target rapamycin (mTOR) inhibitor did not. The proportion of CD25 significantly decreased in THYMO group during the first year after transplantation. CONCLUSION: The frequency of circulating T cell activation marker CD25 in pediatric KT recipients is strongly affected by CNIs, and a high frequency of CD25 is associated with acute rejection during the early posttransplant period. The measurement of T cell activation markers, may become a useful immune monitoring tool after kidney transplantation.

Advanced glycation end products and soluble receptor as markers of oxidative stress in children on hemodialysis.

BACKGROUND: Advanced glycation end products (AGEs) have biological properties that may contribute to the mortality of children on hemodialysis (HD). This study examines the relationship of LMW fluorescence AGEs, oxidized LDL (ox-LDL), soluble receptor AGE (sRAGE) as markers of oxidative stress in children with end stage renal disease (ESRD) undergoing HD. METHOD: Thirty children with ESRD undergoing HD, and 30 healthy, age- and sex-matched children were included. Serum levels of LMW fluorescence AGEs, sRAGE, oxidized LDL (ox-LDL), pre- and post-dialysis urea, high-sensitivity C-reactive protein (hs-CRP), hemoglobin (Hb) and serum albumin (ALB), were measured. RESULTS: Abnormal serum inflammatory changes: elevated levels of LMW AGEs, sRAGE, oxLDL, CRP and urea were exhibited in HD children compared with healthy controls; more so in anemic when compared to non-anemic patients. Significant positive correlation was found between serum levels of AGEs and sRAGE. CONCLUSION: The low molecular weight form of AGEs is associated with oxidative stress in children receiving chronic HD, and may be important in the mechanisms leading to atherosclerosis and inflammation in such patients. LMW AGEs levels showed a negative correlation with sRAGE and both exhibit a significant negative relation to seum urea.

Soluble adhesion molecules as markers of native arteriovenous fistula thrombosis in children on uremia.

Vascular access represents a lifeline for children undergoing hemodialysis. A failure of vascular access among patients receiving regular hemodialysis is associated with increased morbidity, mortality and costs. We assessed the possibility of using soluble adhesion molecules as reliable predictors of vascular access failure in children on hemodialysis. Moreover, we evaluated whether there is an association among the different studied adhesion molecules in hemodialysis patients with thrombosed and non-thrombosed arteriovenous fistula fistulas (AVFs). This study included 55 hemodialysis children, 36 with good access and 19 with access failure, and 20 healthy volunteers. Forty-four patients had native AVFs and 11 patients had tunneled permanent catheter (11with thrombosed and 33 with non-thrombosed AVFs). Serum-soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1 (sICAM-1), soluble E-selectin (sE-selectin) and soluble P-selectin (sP-selectin) were measured using ELISA technique. A significant increase was found in the levels of sVCAM-1, sICAM-1, sE-selectin and sP-selectin versus controls and all hemodialysis patients, hemodialysis patients with good access and hemodialysis patients with access failure (P=0.001 for sVCAM-1 and sICAM-1 and P=0.0001 for sE-selectin and sP-selectin). A significant increase was found in the levels of sVCAM-1, sE-selectin and sP-selectin in both chronic hemodialysis patients with thrombosed and non-thrombosed native AVFs versus controls (P=0.0001 for all parameters). There was significant difference between both chronic hemodialysis patients with thrombosed and non-thrombosed native AVFs as regard to sVCAM-1 (54.64±30.82 versus 25.69±27.96ng/ml, P=0.04). Both sICAM-1 and sP-selectin were positively correlated with the erythropoietin (EPO) dose in hemodialysis children (r=0.31, P=0.04 and r=0.32, P=0.04, respectively). A significant positive association was found between E-selectin and sP-selectin in hemodialysis patients with thrombosed AVFs (r=0.83, P=0.04). There was a significant correlation between sVCAM-1 and EPO dose in thrombosed AVF group (r=0.84, P=0.01). The assessment of serum sVCAM-1 might be useful for the identification of the chronic hemodialysis patients at an increased risk for native AVFs thrombosis. The role of EPO in vascular access failure should be taken into consideration. The clinical relevance of these observations warrants further investigations.

Some amino acids levels: glutamine,glutamate, and homocysteine, in plasma of children with chronic kidney disease.

BACKGROUND: The high prevalence of protein-energy malnutrition is a critical issue for patients with chronic kidney disease (CKD). Serum albumin is the most commonly used nutritional marker. Another index is plasma amino acid (AA) profile. Of these, the plasma levels of glutamine, glutamate and homocysteine, correlate well with nutritional status. We measured some plasma AAs in children with different stages CKD to provide information in monitoring the therapeutic strategy, particularly in AA supplementary therapy or protein restriction. METHODS: Three amino acids were evaluated along with albumin and high sensitivity C-reactive protein (hs-CRP) in 30 patients with advanced CKD stages 4 and 5. They were divided into two groups undergoing conservative treatment (CT) (n=15) or hemodialysis (HD) (n=15). An additional group of patients with nephrotic syndrome [CKD stage 2] was also studied to assess the alterations of plasma free amino acids with the early stage of CKD. Another 30 age- and sex-matched healthy children served as controls. RESULTS: A significant increase in plasma concentration of amino acid glutamine was observed in children with advanced CKD stages 4 and 5 when compared with controls (P=0.02).Plasma glutamine level was significantly higher in ESRD children on HD than in children with nephrotic syndrome (P=0.02). We did not find a significant difference between HD children and CT children as regard to glutamine level. Notable differences were in the plasma homocysteine level detected in the CKD groups patients, which was greater than that in controls (P=0.0001). Plasma homocysteine level was significantly higher in children on HD than in children with nephrotic syndrome (P=0.01). A significant differences was observed in hs-CRP levels between the CKD groups and the controls (P=0.04). Albumin levels were lower in CKD groups than in controls (p=0.01). Glutamine showed significant positive correlations with blood urea level (r=0.84, P=0.002) and blood ammonia level (r=0.72, P=0.0001). On multiple linear regression, urea was the only variable independently associated with an elevated plasma glutamine level (Beta=0.77, P=0.02). CONCLUSION: This study indicates that the advanced stages of CKD are associated with increased plasma concentrations of glutamine and homocysteine. Glutamine retained in the plasma of children with CRF, possibly producing higher levels of the waste products (urea and NH3). Dialysis alone is insufficient to redress completely the abnormalities in AA metabolism in ESRD children. Careful consideration of dialysis and dietary measures are necessary.

Adiponectin: an adipocyte-derived hormone, and its gene encoding in children with chronic kidney disease.

BACKGROUND: The prevalence of cardiovascular disease (CVD) and inflammation is high in patients with chronic kidney disease (CKD). Adiponectin (ADPN) is an adipocytokine that may have significant anti-inflammatory and anti-atherosclerotic effects. Low adiponectin levels have previously been found in patients with high risk for CVD. METHODS: On seventy eight advanced CKD (stages 4 and 5) pediatric patients undergoing maintenance hemodialysis( MHD) or conservative treatment (CT) the following parameters were studied: body mass index, left ventricular mass index(LVMI), serum adiponectin , cholesterol, HDL-cholesterol, high sensitivity C-reactive protein (hs CRP),interleukin 6(IL6) and single-nucleotide polymorphisms (SNPs) in the ADIPOQ gene at positions 45, and 276. Seventy age-and gender-matched healthy subjects served as control subjects. RESULTS: Markedly (P = 0.01) elevated plasma adiponectin levels were observed in CKD patients, especially CT patients, compared to control subjects. The wild type of ADIPOQ 45T > G (T) allele is the main gene for patients and controls. MHD and CT patients had significantly higher frequency of the TT genotypes of +276G > T gene (P = 0.04) compared with control subjects. A significant positive correlation was observed between plasma adiponectin and IL6 level, whereas negative correlations were found between adiponectin level, cholesterol, HDL cholesterol and hs CRP. In a stepwise backward multiple regression model only IL6 (P = 0.001) was independently associated with plasma adiponectin levels. The adiponectin gene the 276 GT+TT genotypes were associated with a higher level of adiponectin . CONCLUSIONS: The present study demonstrated that ADPN is related to several metabolic and inflammatory CV risk factors in a manner consistent with the hypothesis that this protein might have a protective role against these factors. We observed an association between the +276G>T SNP in the adiponectin gene and CKD in children. Genetic variation of +276 gene seemed to have a positive impact on circulating adiponectin levels in CKD patients.

Genetic polymorphism of ACE and the angiotensin II type1 receptor genes in children with chronic kidney disease.

AIM AND METHODS: We investigated the association between polymorphisms of the angiotensin converting enzyme-1 (ACE-1) and angiotensin II type one receptor (AT1RA1166C) genes and the causation of renal disease in 76 advanced chronic kidney disease (CKD) pediatric patients undergoing maintenance hemodialysis (MHD) or conservative treatment (CT). Serum ACE activity and creatine kinase-MB fraction (CK-MB) were measured in all groups. Left ventricular mass index (LVMI) was calculated according to echocardiographic measurements. Seventy healthy controls were also genotyped. RESULTS: The differences of D allele and DI genotype of ACE were found significant between MHD group and the controls (p = 0.0001). ACE-activity and LVMI were higher in MHD, while CK-MB was higher in CT patients than in all other groups. The combined genotype DD v/s ID+II comparison validated that DD genotype was a high risk genotype for hypertension .~89% of the DD CKD patients were found hypertensive in comparison to ~ 61% of patients of non DD genotype(p = 0.02). The MHD group showed an increased frequency of the C allele and CC genotype of the AT1RA1166C polymorphism (P = 0.0001). On multiple linear regression analysis, C-allele was independently associated with hypertension (P = 0.04). CONCLUSION: ACE DD and AT1R A/C genotypes implicated possible roles in the hypertensive state and in renal damage among children with ESRD. This result might be useful in planning therapeutic strategies for individual patients.

Endothelial nitric oxide synthase gene intron4 VNTR polymorphism in patients with chronic kidney disease.

Nitric oxide production is reduced in renal disease, partially due to decreased endothelial nitric oxide production. Evidence indicates that nitric oxide deficiency contributes to cardiovascular events and progression of kidney damage. A polymorphism in intron 4 of the endothelial constitutive nitric oxide synthase (ecNOS) gene is a candidate gene in cardiovascular and renal diseases. We investigated a potential involvement of this polymorphism in chronic renal failure. A case-control study involved 78 children with chronic kidney disease (CKD) and 30 healthy controls. All participants were genotyped for the ecNOS4 polymorphism by the polymerase chain reaction (PCR). Dialyzed (maintenance hemodialysis) and conservative treatment children had significantly higher frequency of the aa genotype and ecNOS4a allele (P<0.05) compared with controls. The combined genotype aa+ab vs. bb comparison validated that a allele is a high-risk allele for end-stage renal disease (ESRD) (P<0.05). Serum nitric oxide level was found to be lower in carriers of the ecNOS 4a allele than in noncarriers (100.29±27.32 vs. 152.73±60.39 µmol/l, P=0.04). Interestingly, 85.95% of the ecNOS 4a allele ESRD patients were found hypertensive in comparison to the 60.67% patients of non noncarriers (bb genotype) (P=0.04). Also, 35.90% of the ecNOS 4a allele ESRD patients were found to have cardiovascular disease in comparison to the 5.13% patients of noncarriers (bb genotype) (P=0.01). On multiple linear regression analysis, a allele was independently associated with hypertension (P=0.03). There was a significantly higher frequency of the ecNOS4a allele carriers among CKD children, both on MHD and conservative treatment than in controls. This suggests that the ecNOS gene polymorphism may be associated with an increased risk of chronic renal failure.

Aluminium and lead abnormalities in children on haemodialysis: relationship with some medications.

INTRODUCTION: The determination of toxic elements in the biological samples of human beings is an important clinical procedure. This study was performed to investigate the prevalence of abnormal blood contents of 2 trace elements (TEs), aluminum (Al),and lead (Pb) in hemodialysis (HD) patients and to analyze their relationship with the medications, such as CaCO(3), Ca acetate, 1,25-dihydroxy vit. D(3), and erythropoietin (EPO), as well as hematocrit level. MATERIAL AND METHODS: We included 43 patients on maintenance HD and they had continued the previously mentioned medications for at least 3 months. None of the patients were on Al containing phosphate binding agents. RESULTS: Serum aluminum and lead levels were significantly increased than in the healthy controls, but levels of both of them were far below toxic values. Male patients had higher mean levels of lead than did females. A strong positive correlation was found between serum Al and serum Pb levels among patients (r = 0.075, p = 0.0001).The serum level of Pb was positively correlated with the serum albumin in HD patients (r = 0.45, p = 0.03). Both serum aluminium and lead levels positively correlated with the EPO dose taken by the patients (r = 0.77, p = 0.0001 and r = 0.67, p = 0.0001 respectively). CONCLUSIONS: The blood level of trace metals of these HD patients was not related to their medications except for the EPO dose. However, caution must be exercised in interpreting this result as dose and duration of medication may play an important role. Al and Pb over load may be considered from the causes of inadequate response to epoetin therapy.

Oxidative stress markers and C-reactive protein in pediatric patients on hemodialysis.

BACKGROUND: Pediatric patients with end-stage renal disease undergoing hemodialysis (HD) are exposed to oxidative stress associated with an impairment of antioxidant defense and an overproduction of oxidative stress markers. Oxidative stress plays a significant role in the development of inflammation in these patients. OBJECTIVES: The high incidence of cardiovascular disease in HD pediatric patients is now well established and the involvement of oxidative stress has been hypothesized. This study focuses on a comparison of plasma total antioxidant capacity (TAC) and lipid peroxidation product and evaluates the relationship between these parameters and high-sensitivity C-reactive protein (hsCRP) in pediatric patients on HD. SUBJECTS AND METHODS: Plasma TAC, lipid peroxidation products, malondialdehyde (MDA) as well as hsCRP were determined in 30 pediatric patients on HD and in 20 healthy controls (HC). RESULTS: TAC and MDA levels were significantly higher in children on HD than in the HC (p < 0.001). The hsCRP values were also significantly higher in HD patients than in HC (p < 0.001). The percentage of HD pediatric patients with CRP >10 mg/l was 30%. The concentrations of TAC and MDA correlated positively with hsCRP in HD patients (TAC: r = 0.52, p < 0.08; MDA: r = 0.75, p < 0.04), but not in HC. CONCLUSION: Our study demonstrates an increase in oxidative stress in children on HD and that the susceptibility to oxidative stress is strongly related to the levels of MDA produced in plasma. hsCRP levels are higher in children on HD than in HC and this is indicative of a higher degree of inflammatory activity in the former patients. These profound disturbances in oxidative stress markers may provide an explanation for the cardiovascular complications in HD patients.