Tumor necrosis factor alpha gene polymorphism affects the pattern of idiopathic nephrotic syndrome in Kuwaiti Arab children.

OBJECTIVES: TNF-α is a pro-inflammatory cytokine that has been implicated in many inflammatory diseases, but its association with idiopathic nephrotic syndrome (INS) is poorly understood. This study looked for an association of TNF-α gene polymorphisms with INS, as well as its effect on steroid responsiveness among Kuwaiti Arab children. METHODS: Genotypes of the TNF-a gene polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism in 151 INS Kuwaiti Arab patients and 64 age and sex-matched controls. Clinical data of all subjects were reviewed. RESULTS: The heterozygous AG genotype was detected in 8.6% of INS patients compared 23.4% of the controls (p < 0.01). Comparing steroid responsiveness, AA genotype was significantly more common in steroid-sensitive nephrotic syndrome (SSNS) cases than steroid-resistant nephrotic syndrome (SRNS) patients (p = 0.001). However, AG genotype was significantly more common in SRNS patients compared to the SSNS cases (p = 0.001). No difference was found between these two subgroups in the GG genotype frequency. CONCLUSION: AG genotype of TNF-a gene polymorphisms may be considered a suitable marker for INS disease among Kuwaiti children. Both AA and AG genotypes may be useful in predicting steroid responsiveness among these cases of Arab ethnicity. The findings might open the era for the use of genetic markers in the early treatment of NS.

Interleukin-4 and Interleukin-13 Gene Polymorphisms in Children With Idiopathic Nephrotic Syndrome.

Background: Idiopathic Nephrotic syndrome (INS) is an immune-mediated disease in which a number of cytokines, including IL-4 and IL-13, have been implicated in the pathogenesis. Cytokine gene polymorphisms might affect their levels and activity. Therefore, may affect INS susceptibility and response to treatment. The aim of the study was to determine the association of IL-4 and IL-13 gene polymorphisms and INS susceptibility and their effects on steroid responsiveness in children. Methods: The polymorphisms in IL-4 and IL-13 genes were detected by PCR-RFLP in 155 INS patients and 64 controls. Results: A total of 132 steroid-sensitive (SS) and 23 steroid resistance (SR) INS patients; mean age 7.3 ± 4.0 years, were included. Male: Female ratio was 2:1. No significant statistical differences were detected in the frequency of CC, CT, and TT genotypes of IL-4 gene compared to controls (P = 0.57, 0.61, and 1.00, respectively). There was no significant difference in the T and C-allele frequencies, in SS and SR subgroups. Analysis of IL-13 gene polymorphism also did not show significant statistical differences in the frequency of QQ, RQ, and RR genotypes compared to controls (P = 0.74, 1.00, and 0.68, respectively). No significant difference was found in the Q and R-allele frequency. However, the heterozygous RQ genotype of the IL13 gene was significantly higher in SS INS patients compared to the SR INS cases (P = 0.04). Conclusion: Our findings did not show an association between IL-4 and IL-13 gene polymorphisms and INS susceptibility. However, IL-13 RQ genotype was expressed more in children with INS who are steroid sensitive.

Serum and Urine Interleukin-6 and Interleukin-8 Levels Do Not Differentiate Acute Pyelonephritis from Lower Urinary Tract Infections in Children.

BACKGROUND: Urinary tract infection (UTI) is common in pediatrics. Infection of the upper urinary tract may cause renal scarring, and subsequently renal failure and hypertension. Permanent renal damage has been suggested to be caused by the host inflammatory response. Therefore, it is crucial to understand the host defense mechanisms against such infection in order to make timely diagnosis. The aim of this study was to evaluate interleukin-6 (IL-6) and IL-8 as potential biomarkers in differentiating acute pyelonephritis (AP) from cystitis (Cys) in children. METHODS: Forty-three children (21 with AP and 22 with Cys) were included. Serum and urinary IL-6 and IL-8 were measured during the acute phase (within 12 hours of presentation) and the convalescent phase (8 weeks post-infection). Thirty-eight healthy children were included as controls. RESULTS: During the acute phase, the mean urinary IL-6 level in the Cys group was significantly higher than that in the controls (17.8 pg/mL vs 14.8 pg/mL, P=0.03), while the serum levels were significantly higher in both the Cys and AP groups than in the controls (19.5 pg/mL, 19.4 pg/mL, 15 pg/mL, P=0.005 and 0.02, respectively). During the convalescent phase, serum and urinary IL-6 levels were higher in patients than in controls. Urinary IL-8 levels were significantly higher in both the AP and Cys groups compared to controls (206.5 pg/mL, 291.8 pg/mL, 89.4 pg/mL, P=0.05 and 0.02, respectively) during the acute phase. Serum IL-8 was not significantly different between the 3 groups. Nonetheless, no significant differences were found between the AP and Cys groups, in urinary or serum levels of IL-6 or IL-8, during both phases. CONCLUSION: IL-6 and IL-8 levels are elevated in patients with UTI. However, the levels did not differentiate between AP and cystitis. Further studies are warranted to evaluate their roles as indicators of the site of UTIs.

Factors predicting students' performance in the final pediatrics OSCE.

BACKGROUND: Objective Structured Clinical Examinations (OSCEs) have been used to assess the clinical competence of medical students for decades. Limited data are available on the factors that predict students' performance on the OSCEs. The aim of our study was to evaluate the factors predicting performance on the pediatrics final OSCE, including the timing of students' clerkship and their performance on the in-training OSCE and written examinations. METHODS: Grades in pediatrics for 3 consecutive academic years (2013-2016) were included. The average scores of the in-training OSCEs, written and final OSCEs and written exams were compared among the three years using the analysis of variance (ANOVA) test. The correlations between performance on the final OSCEs and the in-training OSCEs, in-training written exams and final written exams were studied using Spearman's Rho correlation test. The effect of the timing of the clerkship on the final OSCE performance was evaluated. RESULTS: A total of 286 students' records were included. There were 115 male students and 171 female students (M:F 1:1.5). There were strong positive correlations between students' performance on the in-training examinations (OSCE and written) and the final OSCE (correlation coefficients of 0.508 and 0.473, respectively). The final written exam scores were positively correlated with the final OSCEs (r = 0.448). There was no significant effect of the timing of the clerkship. CONCLUSIONS: Students' performance on in-training examinations might predict their final OSCE scores. Thus, it is important to provide students with the necessary intervention at an early stage to reduce failure rates. The final OSCE performance does not seem to be affected by the timing of the clerkship.

IgA Enhances IGF-1 Mitogenic Activity Via Receptor Modulation in Glomerular Mesangial Cells: Implications for IgA-Induced Nephropathy.

BACKGROUND/AIM: Glomerulonephritis due to mesangial proliferation is responsible for renal dysfunction in IgA nephropathy (IgAN), however molecular mechanisms of pathogenesis are not well known. We examined the effect of IgA on Insulin-like Growth Factor-1 (IGF-1) activity, a potent mitogen with vital role in growth and development of children, and IGF-1 receptor (IGF-1R) in cultures of glomerular mesangial cells (GMC). METHODS: GMC were isolated from rat kidneys using sieving and enzymatic digestion of tissue homogenates, and cultured in RPMI 1640 medium. GMC cultures were treated with IgA (0-10 µg/ml) in the presence or absence of IGF-1 and fetal bovine serum (FBS), and BrdU incorporation was measured. IGF-1 levels were assayed along with real-time PCR quantification of IGF-1R mRNA. RESULTS: Treatment of GMC with IgA (5 -10 µg/ml) significantly (p < 0.01) increased the BrdU incorporation in the presence or absence of FBS or IGF-1. IgA-mediated effects were more pronounced in IGF-1 treated cells that were significantly (p < 0.01) blocked by pretreatment of cells with IGF-1 receptor antibody or genistein. IgA significantly increased the levels of IGF-1 in culture supernatants and GMC homogenates. IGF-1R mRNA was significantly (p < 0.01) increased in IgA treated cells particularly by co-treatment with IGF-1. CONCLUSION: These findings show that IgA enhances the IGF-1 activity in GMC via stimulation of IGF-1R gene transcription and suggest a role for IGF-1 in pathogenesis of IgAN.

NOX-mediated impairment of PDGF-induced DNA synthesis in peripheral blood lymphocytes of children with idiopathic nephrotic syndrome.

BackgroundCellular oxidative stress, inflammatory responses, and immunogenic events are involved in pathogenesis of idiopathic nephrotic syndrome (INS); however, the exact mechanism remains unknown. We examined NADPH oxidase (NOX) activity and platelet-derived growth factor (PDGF)-induced DNA synthesis in peripheral blood lymphocytes (PBL) of patients with INS.MethodsPBL from 15 patients with INS and 15 age- and gender-matched controls were isolated, and enzyme activities of NOX, catalase, and superoxide dismutase (SOD) were measured along with the assay of malondialdehyde levels and bromo-deoxyuridine incorporation. Protein expression of NOX-1 was measured using western blot analysis.ResultsPatients with INS had significantly (P<0.01) higher NOX activity and increased protein expression of NOX-1 in PBL as compared with controls. Catalase and SOD activities were markedly lower with lipid peroxide levels significantly (P<0.01) increased in patients with INS. Ex vivo DNA synthesis in PDGF-stimulated PBL was significantly (P<0.01) reduced in patients with INS; however, diphenyliodonium, an inhibitor of NOX, markedly corrected impairment in growth factor-induced BrdU incorporation.ConclusionsThese results show that NOX activation might have a role in regulation of lymphocytic activity in patients with INS through the impairment of PDGF mitogenic function and might contribute toward pathogenesis of nephrotic syndrome.

Urinary excretion of IL-1ß, IL-6 and IL-8 cytokines during relapse and remission of idiopathic nephrotic syndrome.

BACKGROUND/AIM: The role of pro-inflammatory cytokines in the immunopathogenesis of idiopathic nephrotic syndrome had been widely postulated. Reports on the release of cytokines, during idiopathic nephrotic syndrome (INS) activation, were conflicting in defining a specific interleukin pattern during relapse and remission of the disease. The aim of this study was to explore the role of IL-1ß, IL-6 and IL-8 in the pathophysiology of INS during relapse and remission. PATIENTS AND METHODS: A total of 37 INS patients were included. Their demographic and biochemical data were reviewed. Levels of IL-1ß, IL-6 and IL-8 were measured in the urine of patients during relapse and remission of the disease. Urine samples from 30 age- and sex-matched controls were checked for the same 3 cytokines. RESULTS: Mean age of patients at study was 6.4 ± 3.2 years (range: 14 months-12 years). Male:female ratio was 24:13. Mean serum creatinine was 47 ± 13 µmol/L, and mean serum albumin was 21 ± 7 g/L. Mean urinary IL-1ß, IL6 and IL8 levels, corrected to urinary creatinine, in patients during relapse were 132.94 ± 654.97, 217.82 ± 1124.31 and 150.227 ± 523.97 pg/µmol compared to 9.11 ± 40.75, 0.146 ± 0.652, and 6.455 ± 24.53 pg/µmol in controls, respectively (P = 0.02, 0.03 and 0.014, respectively). No significant difference was reported in the mean level of the 3 cytokines compared to controls during remission (P = 0.94, 0.092 and 0.076). CONCLUSION: Our results support the role of T-cell activation and the subsequent release of IL-1ß, IL6 and IL8 in the pathogenesis of relapses in INS. The use of steroid-sparing cytokine blockers in managing relapses of INS remains a tempting challenge.

Vitamin D receptor gene TaqI and Apal polymorphisms and steroid responsiveness in childhood idiopathic nephrotic syndrome.

BACKGROUND: Vitamin D activity is controlled by vitamin D receptors (VDRs), which are affected by different genetic polymorphisms, including TaqI and Apal restriction fragment length polymorphisms (RFLPs), which have been reported to be associated with several diseases. The aim of this study was to determine the frequency and the association of VDR gene polymorphisms with idiopathic nephrotic syndrome (INS) and steroid responsiveness in Kuwaiti children. SUBJECTS AND METHODS: Genotypes of the VDR TaqI gene polymorphism and the Apal gene polymorphism were analyzed using polymerase chain reaction-RFLP in 78 INS patients and 56 matched controls. RESULTS: A total of 78 INS (62 steroid sensitive [SS] and 16 steroid resistant [SR]) patients with a mean age of 6.5±3.1 years were studied. Male:female ratio was 2:1. The TT genotype of VDR-TaqI polymorphism was detected in 41% of the INS patients compared to 42% of the controls (P=0.816). The heterozygous TC genotype was detected in 33% of INS patients compared to 46% of the controls (P=0.462). The CC genotype was detected in 25.6% of INS patients and 21% of the controls (P=0.719). The C-allele frequency, in its homozygous and heterozygous forms, was 71% in INS patients compared to 63% in the controls (P=0.342). Similarly, no significant difference was detected in terms of VDR-Apal polymorphism in INS patients compared to the controls for all the three genotypes (P=0.76, P=0.207, and P=0.364, respectively, for GG, GT, and TT genotypes). The T-allele frequency, in its homozygous and heterozygous forms, was 89% in INS patients compared to 93% in the controls (P=0.076). No significant difference was found in any of the allele frequencies between SS and SR subgroups when compared with each other or when compared to the controls. CONCLUSION: Our data do not support the use of VDR-TaqI or -Apal gene polymorphisms as genetic markers of INS nor do they predict steroid responsiveness in children with the disease.

Paraoxnase1 Gene Polymorphism in Childhood Idiopathic Nephrotic Syndrome.

BACKGROUND: Paraoxonase1 (PON1) is a serum enzyme bound to high-density lipoproteins with antioxidant properties. Molecular studies of PON1 revealed 2 polymorphic sites at amino acids 55 and 192 resulting in 2 different allozymes, the L and M-genotype at residue 55 and A and B at site 192, respectively. We have studied the association between PON1 gene polymorphisms and the minimal change nephrotic syndrome/focal segmental glomerulosclerosis (MCNS/FSGS) types of idiopathic nephrotic syndrome (INS) in Kuwaiti Arab children. METHODS: The PON1 gene, 55 and 192 polymorphisms were analyzed in 50 children with INS (32 MSCN, 18 FSGS) and compared to 50 controls. Serum creatinine, albumin and lipids were measured in all subjects. RESULTS: The LL genotype was detected in 50% of the INS patients compared to 48% of controls (p = 0.84). The heterozygous LM genotype was detected in 42% of INS patients compared 36% of controls (p = 0.68). The MM-genotype was detected in 8% of INS patients and 16% of controls (p = 0.35). The L-allele frequency in its homozygous and heterozygous forms was found in 71% of INS patients compared to 66% controls (p = 0.54). The L-allele frequency (LM and LL) was significantly higher in FSGS compared to MCNS patients (p = 0.0001) and when compared to controls (p = 0.0007). All patients and controls had the AA form of the 192 PON1 gene polymorphism. CONCLUSION: Our data demonstrate a strong association between the L-allele of PON1 gene 55 polymorphism with FSGS in Kuwaiti Arab children with INS. PON1 genotyping can help in the early prediction of FSGS, which might guide clinicians to a better therapeutic approach.

Chronic renal failure in Kuwaiti children: an eight-year experience.

Over an 8-year period (January 1996 to December 2003), a total of 171 patients below the age of 15 years were diagnosed with chronic renal failure. The mean incidence rate of CRF in Kuwaiti children was found to be 38.2 per million children per year, with a peak incidence of 55 per million children per year. While the mean age at diagnosis was 33+/-12 months (range: 1 month to 15 years), the male:female ratio was 2.7:1. Etiological factors for chronic renal failure included congenital urological malformation (61.9%), chronic glomerulopathies (5.2%), hereditary nephropathies (21%), multi-system disease (0.5%), chronic pyelonephritis (without VUR) (4.6%), tumors (0.6%), ischemic renal disease (1.1%) and unknown etiology (1.7%). Thirty percent of patients reached end-stage renal disease within a mean of 18 months following diagnosis. The overall mortality before reaching ESRD was reported to be 4%. Kuwait has one of the highest incidence and prevalence rates of CRF in children. It is likely that genetic and hereditary factors are the cause of these high rates.

Renal abnormalities in congenital chloride diarrhea.

Congenital chloride diarrhea (CLD) is a rare autosomal recessive disorder caused by a defect in the chloride/ bicarbonate exchange in the ileum and colon. It is characterized by watery diarrhea, abdominal distension, hypochloremic hypokalemic metabolic alkalosis with high fecal content of chloride (>90 mmol/l). We report 3 patients with CLD associated with various renal abnormalities including chronic renal failure secondary to renal hypoplasia, nephrocalcinosis and congenital nephrotic syndrome.