Oxidant stress in primary nephrotic syndrome: does it modulate the response to corticosteroids?

Association of Catalase Gene Polymorphisms with Idiopathic Nephrotic Syndrome in a Chinese Pediatric Population

OBJECTIVE

Our aim was to investigate the association between gene polymorphisms in catalase (CAT), a well-known oxidative stress regulator, and susceptibility to idiopathic nephrotic syndrome (INS) or responses to steroid therapy in a Chinese pediatric population.

METHODS

We analyzed 3 CAT single-nucleotide polymorphisms (SNVs; rs7943316, rs769217, and rs12270780) using multi-polymerase chain reaction combined with next-generation sequencing in 183 INS patients and 100 healthy controls.

RESULTS

For the allele and genotype frequencies of the CAT SNVs, no significant differences were observed between INS patients and controls. Patients with C allele of CAT rs769217 had a higher risk of developing steroid-dependent nephrotic syndrome than the steroid-sensitive nephrotic syndrome patients (P = 0.018; odds ratio = 1.76).

CONCLUSION

Our data suggests that genetic variations in CAT were unlikely to confer susceptibility to INS in Chinese children, whereas the C allele of the CAT rs769217 polymorphism showed a strong association with steroid-dependent responses in Chinese INS children.

The risk factors for children with primary nephrotic syndrome: a systematic review and meta-analysis

BACKGROUND

To evaluate the risk factors of primary nephrotic syndrome (PNS) with urinary tract infection (UTI) in children.

METHODS

Multiple databases including PubMed, Excerpta Medica Database (EMBASE), Web of Science (WOS), the Cochrane Library, and China National Knowledge Infrastructure (CNKI) were used to search for relevant studies, which were full-text articles involved in the evaluation of differences between PNS with UTI and without UTI. All included articles were assessed for quality and the data analyses were conducted with Review Manager (5.4). Forest plots, sensitivity analysis, and bias analysis were also performed on the included articles.

RESULTS

Eight studies were included in this meta-analysis, with a total of 3,274 patients. Meta-analysis showed that a low level of serum albumin [mean difference (MD): -0.32 g/dL; 95% confidence interval (CI): (-0.55, -0.08); P=0.008], a low level of serum total protein [MD: -0.16 g/dL; 95% CI: (-0.20, -0.12); P<0.00001], a high level of urinary protein [MD: 5.09 mg/d; 95% CI: (3.13, 7.05); P<0.00001], a lower level of serum urea nitrogen [MD: -0.10 mg/dL; 95% CI: (-0.18, -0.02); P=0.01], and a higher level of serum cholesterol [MD: 2.26 mg/dL; 95% CI: (0.74, 3.78)] had a higher risk of PNS with UTI. There was no obvious publication bias among included studies.

DISCUSSION

Our research demonstrated that a low level of serum albumin, a low level of serum total protein, a high level of urinary protein, a low level of serum urea nitrogen, and a high level of serum cholesterol were the risk factors of PNS with UTI in children.

The long and winding road to the etiology of idiopathic nephrotic syndrome in children: Focusing on abnormalities in the gut microbiota

Childhood nephrotic syndrome is idiopathic in 90% of cases. Despite its relatively high prevalence (30-35 per 100 000 individuals under 15 years old), the etiology of the disease remains elusive. It has become clear that oxidants are elevated, and antioxidants are decreased, at onset of idiopathic nephrotic syndrome (INS). It was suggested that overexpression of podocyte CD80 induced by abnormalities of Tregs was involved in the pathogenesis of INS. Subsequently, it became clear that quantitative or qualitative reduction of Tregs has a profound impact on the development of INS. To address why Tregs are decreased at onset of INS, it was hypothesized that a decrease in Tregs may be associated with dysbiosis. Given the critical role of butyrate-producing bacteria in the differentiation of Tregs, the gut microbiota was analyzed with a particular focus on the abundance of butyrate-producing bacteria, and it was found that pediatric patients with INS had low levels of butyrate in their stool and a low percentage of butyrate-producing bacteria. Interestingly, it was recently reported that gut dysbiosis increases oxidative stress in the intestinal tract. Taken together, we currently hypothesize that gut dysbiosis is associated with a predisposition to INS because of immunological abnormalities characterized by abnormal Tregs with increased oxidative stress.

Increased ischemia-modified albumin levels in children with steroid-sensitive nephrotic syndrome

Objective:

Growing evidence shows that oxidative stress plays an important role in the development and progression of nephrotic syndrome (NS). In this study, we aimed to examine serum IMA levels as an indicator of oxidative stress in children with steroid-sensitive NS (SSNS) in remission and relapse.

Methods:

This cross-sectional study was carried out at the Pediatric Nephrology Unit of Sanliurfa Training and Research Hospital, Sanliurfa, Turkey, from April 2019 to December 2019. In this study Serum IMA and albumin levels were determined in 70 children with SSNS and 45 healthy controls. Among the children with SSNS, 50 were in remission and 20 were in relapse. Then, adjusted IMA levels were calculated from the IMA/albumin ratio.

Results:

IMA and adjusted IMA levels significantly increased and albumin significantly decreased in children with SSNS in relapse and remission compared with those of the healthy controls. Moreover, these alterations were more prominent in the relapse group than in the remission group. IMA was inversely correlated with albumin in children with SSNS (r= −0.881, p= <0.001).

Conclusions:

Our findings demonstrated that elevated IMA and adjusted IMA levels observed in patients with SSNS were associated with increased oxidative stress and could indirectly reflect the degree of oxidative damage in glomerular structures.

Paraoxonase Activity and Lipid Profile in Paediatric Nephrotic Syndrome: A Cross-sectional Study

INTRODUCTION

Dyslipidaemia of Nephrotic Syndrome (NS) is known to be linked to oxidative reactions and atherosclerosis. Paraoxonase (PON1) has been implicated in the prevention of Low Density Lipoprotein (LDL) lipid peroxidation and also degrades biologically active oxidised lipids in lipoprotein.

AIM

The present study was taken up to assess PON1 levels in paediatric nephrotic syndrome and also to see if any correlation exists between lipid parameters and PON1.

MATERIALS AND METHODS

This study consists of Group 1 with 40 cases of NS in the age group of 2-14 years and Group 2 with 40 age and sex matched healthy controls. Lipid profile and paraoxonase activity was measured in serum samples of both the groups.

RESULTS

Statistical analysis by student's t-test showed that the mean levels of Total Cholesterol, Trigylycerides, LDL, and VLDL were significantly increased in Group 1 when compared to Group 2 (p <0.001). The mean levels of HDL were similar in both groups. The levels of PON1 were significantly lowered in Group 1 when compared to Group 2. Correlation studies showed no significant correlation between lipid profile and PON1.

CONCLUSION

Cases have atherosclerotic dyslipidaemia and significantly decreased PON1 activity. Decreased PON1 may lead to increased oxidation of LDL accelerating the process of atherosclerosis.

Plasma levels of oxidative stress in children with steroid-sensitive nephrotic syndrome and their predictive value for relapse frequency

BACKGROUND

Oxidative stress has been reported to play an important role in children with primary nephrotic syndrome (PNS). However, the results of previous studies are controversial.

METHODS

Forty children with steroid-sensitive nephrotic syndrome (SSNS) and 20 age- and sex-matched healthy controls were enrolled. Patients were followed-up for 12-18 months and divided into three subgroups: frequent relapse (n = 10), non-frequent relapse (n = 12), and non-relapse (n = 18). The plasma levels of advanced oxidation protein products (AOPP), malondialdehyde (MDA), and superoxide dismutase (SOD) were tested in controls and patient group at first presentation and after 4 weeks of steroid treatment.

RESULTS

Patients had higher AOPP and MDA levels but lower SOD compared with controls. AOPP levels were significantly higher in the frequent relapse subgroup compared with the non-frequent relapse and non-relapse subgroups, respectively. No significant differences were found in the plasma levels of MDA and SOD among the three subgroups. AOPP >87.55 μmol/l before steroid treatment and AOPP >78.5 μmol/l after 4-week steroid treatment were positively correlated with the relapse frequency in patients with SSNS.

CONCLUSIONS

Children with SSNS have oxidative stress. The plasma levels of AOPP before and after 4-week steroid treatment may predict whether patients with SSNS will relapse frequently.

Trace elements in children suffering from idiopathic nephrotic syndrome

OBJECTIVE

Trace elements play a significant role in several metabolic processes and often circulate in the blood binding to protein. The purpose of this study was to determine the status of selenium, zinc, and boron in idiopathic nephrotic syndrome patients in active and remission phases.

MATERIALS AND METHODS

Fourteen patients and fourteen healthy age-matched controls were included in the study. The selenium, zinc and boron level in plasma and urine were measured by the inductively coupled plasma mass spectrometry.

RESULTS

The plasma levels of zinc and selenium were significantly lower in both active and remission patients (for all p=0.0001). The plasma boron level was significantly lower only in patients in active phase (p=0.0002 vs control). The concentrations of urinary boron and selenium were significantly higher during active phase compared with remission (p=0.0003 and 0.0001, respectively).

CONCLUSION

Supplementation with zinc, selenium and boron may be justified in patients suffering with this disease.

Oxidative status parameters in children with urinary tract infection

Introduction:

Urinary tract infection (UTI) is one of the most common bacterial infectious diseases in children. The aim of this study was to determine the total prooxidant and antioxidant capacity of children with UTI, as well as changes of oxidative status parameters according to acute inflammation persistence and acute kidney injury (AKI) development.

Materials and methods:

The patients enrolled in the study comprised 50 Caucasian children (median age was 6 months) with UTI. Total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), inflammation marker C-reactive protein (CRP) and renal function parameters urea and creatinine were analyzed in patient’s serums.

Results:

According to duration of inflammation during UTI, TAS values were significantly higher (0.99 vs. 0.58 mmol/L, P = 0.017) and OSI values were significantly lower (0.032 vs. 0.041 AU, P = 0.037) in the subjects with longer duration of inflammation than in the subjects with shorter duration of inflammation. We did not find significant difference in basal values of oxidative status parameters according to AKI development.

Conclusions:

OSI values could detect the simultaneous change of TAS and TOS due to change in the oxidative-antioxidant balance during the recovery of children with UTI. TAS and OSI as markers of oxidative stress during UTI are sensitive to accompanying inflammatory condition. Further investigations are needed to evaluate whether TAS, TOS and OSI could be used to monitor disease severity in children with UTI.

Serum levels of malondialdehyde, vitamin C and E in idiopathic nephrotic syndrome: a meta-analysis

It is well documented that oxidative stress is involved in the pathogenesis of idiopathic nephrotic syndrome (INS). Malondialdehyde (MDA) is a measurement of lipid oxidation; vitamin C and E are important components of antioxidants. However, the association between MDA, vitamin C or E levels and INS remains elusive. A meta-analysis was performed to investigate the alteration of serum levels of MDA, vitamin C and E in INS compared with controls. Eight studies were included in our meta-analysis according to predefined criteria. Active INS patients demonstrated significantly higher level of serum MDA (SMD: 2.13, 95% CI: 1.511 to 2.749, p < 10(-4)), markedly lower levels of serum vitamin C (SMD: -1.449, 95% CI: -2.616 to -0.281, p = 0.015) and E (SMD: -1.45, 95% CI: -2.544 to -0.356, p = 0.009) compared with those in controls. Active steroid-sensitive nephrotic syndrome (SSNS) patients showed comparable levels of serum vitamin C and E to those in controls. INS subjects in the remission stage demonstrated significantly higher level of serum MDA (SMD: 1.028, 95% CI: 0.438 to 1.617, p < 10(-4)), markedly lower level of serum vitamin C (SMD: -2.235, 95% CI: -3.048 to -1.421, p < 10(4)) and similar level of serum vitamin E compared with those in controls. No significant publication bias was observed. In conclusion, the disorder of MDA and vitamin C persists in the remission stage of INS. It seems that the serum levels of vitamin C and E is associated with the responsiveness of INS to steroids. However, more studies should be performed in the future.

Subclinical cardiovascular disease and its association with risk factors in children with steroid-resistant nephrotic syndrome

BACKGROUND

The aim of this study was to evaluate the presence of subclinical cardiovascular disease (CVD) and its relation to risk factors in pediatric patients with steroid-resistant nephrotic syndrome (NS).

METHODS

Thirty-seven patients with normal renal function were compared with 22 healthy controls regarding the presence of subclinical CVD. Measurements included aortic pulse wave velocity (PWV), carotid intima media thickness (IMT), and left ventricular mass (LVM). Patients were additionally assessed for blood pressure (BP) pattern and the presence of hypertension by 24-h ambulatory blood pressure monitoring.

RESULTS

Compared with the controls, patients had significantly higher mean aortic PWV-standard deviation scores (SDS), mean carotid IMT-SDS, and LVM index (p < 0.001 for all). Increased aortic PWV was noted in 5 % of patients, increased carotid IMT in 22 %, and increased LVM index in 19 %. Five patients (14 %) were hypertensive, and mean BP indexes, SDS, and BP loads during nighttime were significantly higher than those during daytime (p < 0.001 for all). Multivariate analysis revealed a significant relationship between PWV-SDS and ferritin (R(2) = 0.269, p = 0.006) and between carotid IMT-SDS and proteinuria (R(2) = 0.141, p = 0.022). The LVM index was independently associated only with higher body mass index SDS (R(2) = 0.317, p < 0.001). In addition, six patients (16 %) had multiple abnormal subclinical CVD markers, and increased subclinical CVD risk was independently associated only with higher low-density lipoprotein cholesterol (R(2) = 0.292, p = 0.044).

CONCLUSIONS

Based on these results, steroid-resistant NS children generally are at high risk of cardiovascular complications, but the increased risk is likely to be multifactorial.

Evaluation of paraoxonase activity in children with nephrotic syndrome

Background

It has been proposed that reactive oxygen species (ROS) is involved in the pathogenesis of various diseases. Paraoxonase, a high-density lipoprotein associated enzyme, prevents low-density lipoproteins from oxidation.

Objectives

The aim of the present study was to investigate the serum activities of paraoxonase-1 (PON-1), and aryleterase (ARE) as well as total antioxidant capacity (TAC) in children with nephrotic syndrome in acute and remission phase.

Patients and Methods

The study consisted of 20 patients in acute and remission phases and 23 healthy controls. PON-1 and ARE activities were determined spectrophotometrically using paraoxone and phenyacetate as substrate, respectively. TAC was measured using ferric reducing ability of plasma (FRAP).

Results

The levels of PON, ARE, and TAC were significantly lower in acute phase of nephrotic syndrome compared with the remission phase. The levels of PON, ARE and TAC increased in remission phase.

Conclusions

Our results revealed that the determination of paraoxonase activity might be a biomarker for responses to nephrotic syndrome treatment, which needs to be fully clarified.