Kidney volume normative values in Central European children aged 0-19 years: a multicenter study.

BACKGROUND AND OBJECITVES: The currently available kidney volume normative values in children are restricted to small populations from single-centre studies not assessing kidney function and including none or only a small number of adolescents. This study aimed to obtain ultrasound-based kidney volume normative values derived from a large European White/Caucasian paediatric population with normal kidney function. METHODS: After recruitment of 1427 children aged 0-19 years, 1396 individuals with no history of kidney disease and normal estimated glomerular filtration rate were selected for the sonographic evaluation of kidney volume. Kidney volume was correlated with age, height, weight, body surface area and body mass index. Kidney volume curves and tables related to anthropometric parameters were generated using the LMS method. Kidney volume predictors were evaluated using multivariate regression analysis with collinearity checks. RESULTS: No clinically significant differences in kidney volume in relation to height were found between males and females, between supine and prone position and between left and right kidneys. Males had, however, larger age-related kidney volumes than females in most age categories. For the prediction of kidney volume, the highest coefficient correlation was observed for body surface area (r = 0.94), followed by weight (r = 0.92), height (r = 0.91), age (r = 0.91), and body mass index (r = 0.67; p < 0.001 for all). CONCLUSIONS: This study presents LMS-percentile curves and tables for kidney volume which can be used as reference values for children aged 0-19 years.

A multicenter retrospective study of calcineurin inhibitors in nephrotic syndrome secondary to podocyte gene variants.

While 44-83% of children with steroid-resistant nephrotic syndrome (SRNS) without a proven genetic cause respond to treatment with a calcineurin inhibitor (CNI), current guidelines recommend against the use of immunosuppression in monogenic SRNS. This is despite existing evidence suggesting that remission with CNI treatment is possible and can improve prognosis in some cases of monogenic SRNS. Herein, our retrospective study assessed response frequency, predictors of response and kidney function outcomes among children with monogenic SRNS treated with a CNI for at least three months. Data from 203 cases (age 0-18 years) were collected from 37 pediatric nephrology centers. Variant pathogenicity was reviewed by a geneticist, and 122 patients with a pathogenic and 19 with a possible pathogenic genotype were included in the analysis. After six months of treatment and at last visit, 27.6% and 22.5% of all patients respectively, demonstrated partial or full response. Achievement of at least partial response at six months of treatment conferred a significant reduction in kidney failure risk at last follow-up compared to no response (hazard ratio [95% confidence interval] 0.25, [0.10-0.62]). Moreover, risk of kidney failure was significantly lower when only those with a follow-up longer than two years were considered (hazard ratio 0.35, [0.14-0.91]). Higher serum albumin level at CNI initiation was the only factor related to increased likelihood of significant remission at six months (odds ratio [95% confidence interval] 1.16, [1.08-1.24]). Thus, our findings justify a treatment trial with a CNI also in children with monogenic SRNS.

Kidney length normative values - new percentiles by age and body surface area in Central European children and adolescents.

BACKGROUND: Kidney size evaluation is an essential examination in pediatric nephrology. While body length/height is the best predictor of kidney length, age-based and body surface area (BSA)-based normative values may be useful in clinical practice or research. This study aimed to establish ultrasound-based kidney length lambda-mu-sigma (LMS) percentiles by age and BSA in healthy children. METHODS: In 1758 Polish and Lithuanian children (868 boys, 49%) aged 0-19 years, kidney length was measured using ultrasonography. In all participants, anthropometric measurements were taken and kidney function was evaluated based on serum creatinine concentration. Participants with chronic or kidney diseases, abnormal kidney function, or pathologies in sonographic examination were excluded from the analysis. RESULTS: Kidney length (median kidney length) increased progressively from infancy to the age of 18 years, from 60.1 to 114.2 mm in males, and from 57.3 to 105.2 mm in females. A gradual increase of kidney length (50th percentile) in relation to BSA (from 46.1 mm in infants with a BSA of 0-1.2 m2 to 118.3 mm in adolescents with a BSA of 2.6-2.8 m2) was also observed. LMS percentiles by age (stratified by sex) and BSA were determined and presented as graphs and tables of percentiles and LMS parameters by 1-year age intervals and 0.2 m2 of BSA, respectively. CONCLUSIONS: We present the first age- and BSA-based kidney length LMS normative values based on the largest pediatric cohort to date, which can be used in both clinical practice and research studies. A higher resolution version of the Graphical abstract is available as Supplementary information.

Oral Coenzyme Q10 supplementation leads to better preservation of kidney function in steroid-resistant nephrotic syndrome due to primary Coenzyme Q10 deficiency.

Primary Coenzyme Q10 (CoQ10) deficiency is an ultra-rare disorder caused by defects in genes involved in CoQ10 biosynthesis leading to multidrug-resistant nephrotic syndrome as the hallmark kidney manifestation. Promising early results have been reported anecdotally with oral CoQ10 supplementation. However, the long-term efficacy and optimal prescription remain to be established. In a global effort, we collected and analyzed information from 116 patients who received CoQ10 supplements for primary CoQ10 deficiency due to biallelic pathogenic variants in either the COQ2, COQ6 or COQ8B genes. Median duration of follow up on treatment was two years. The effect of treatment on proteinuria was assessed, and kidney survival was analyzed in 41 patients younger than 18 years with chronic kidney disease stage 1-4 at the start of treatment compared with that of an untreated cohort matched by genotype, age, kidney function, and proteinuria. CoQ10 supplementation was associated with a substantial and significant sustained reduction of proteinuria by 88% at 12 months. Complete remission of proteinuria was more frequently observed in COQ6 disease. CoQ10 supplementation led to significantly better preservation of kidney function (5-year kidney failure-free survival 62% vs. 19%) with an improvement in general condition and neurological manifestations. Side effects of treatment were uncommon and mild. Thus, our findings indicate that all patients diagnosed with primary CoQ10 deficiency should receive early and life-long CoQ10 supplementation to decelerate the progression of kidney disease and prevent further damage to other organs.

Variation of the clinical spectrum and genotype-phenotype associations in Coenzyme Q10 deficiency associated glomerulopathy.

Primary Coenzyme Q10 deficiency is a rare mitochondriopathy with a wide spectrum of organ involvement, including steroid-resistant nephrotic syndrome mainly associated with disease-causing variants in the genes COQ2, COQ6 or COQ8B. We performed a systematic literature review, PodoNet, mitoNET, and CCGKDD registries queries and an online survey, collecting comprehensive clinical and genetic data of 251 patients spanning 173 published (47 updated) and 78 new cases. Kidney disease was first diagnosed at median age 1.0, 1.2 and 9.8 years in individuals with disease-causing variants in COQ2, COQ6 and COQ8B, respectively. Isolated kidney involvement at diagnosis occurred in 34% of COQ2, 10.8% of COQ6 and 70.7% of COQ8B variant individuals. Classic infantile multiorgan involvement comprised 22% of the COQ2 variant cohort while 47% of them developed neurological symptoms at median age 2.7 years. The association of steroid-resistant nephrotic syndrome and sensorineural hearing loss was confirmed as the distinctive phenotype of COQ6 variants, with hearing impairment manifesting at average age three years. None of the patients with COQ8B variants, but 50% of patients with COQ2 and COQ6 variants progressed to kidney failure by age five. At adult age, kidney survival was equally poor (20-25%) across all disorders. A number of sequence variants, including putative local founder mutations, had divergent clinical presentations, in terms of onset age, kidney and non-kidney manifestations and kidney survival. Milder kidney phenotype was present in those with biallelic truncating variants within the COQ8B variant cohort. Thus, significant intra- and inter-familial phenotype variability was observed, suggesting both genetic and non-genetic modifiers of disease severity.

Kidney length normative values in children aged 0-19 years - a multicenter study.

BACKGROUND: Currently used pediatric kidney length normative values are based on small single-center studies, do not include kidney function assessment, and focus mostly on newborns and infants. We aimed to develop ultrasound-based kidney length normative values derived from a large group of European Caucasian children with normal kidney function. METHODS: Out of 1,782 children aged 0-19 years, 1,758 individuals with no present or past kidney disease and normal estimated glomerular filtration rate had sonographic assessment of kidney length. The results were correlated with anthropometric parameters and estimated glomerular filtration rate. Kidney length was correlated with age, height, body surface area, and body mass index. Height-related kidney length curves and table were generated using the LMS method. Multivariate regression analysis with collinearity checks was used to evaluate kidney length predictors. RESULTS: There was no significant difference in kidney size in relation to height between boys and girls. We found significant (p < 0.001), but clinically unimportant (Cohen's D effect size = 0.04 and 0.06) differences between prone vs. supine position (mean paired difference = 0.64 mm, 95% CI = 0.49-0.77) and left vs. right kidneys (mean paired difference = 1.03 mm, 95% CI = 0.83-1.21), respectively. For kidney length prediction, the highest coefficient correlation was observed with height (adjusted R2 = 0.87, p < 0.0001). CONCLUSIONS: We present height-related LMS-percentile curves and tables of kidney length which may serve as normative values for kidney length in children from birth to 19 years of age. The most significant predictor of kidney length was statural height.

Burnout Syndrome among Pediatric Nephrologists-Report on Its Prevalence, Severity, and Predisposing Factors.

BACKGROUND AND OBJECTIVES: Burnout is an occupation-related syndrome comprising emotional exhaustion, depersonalization, and reduced feelings of work-related personal accomplishments. There are reports on burnout among adult nephrologists and general pediatricians, but little is known about burnout among pediatric nephrologists. The aim of our study was to assess the prevalence and severity of burnout syndrome among Polish pediatric nephrologists. MATERIALS AND METHODS: A 25-item study survey consisting of abbreviated Maslach Burnout Inventory and additional self-created questions about work-related factors was completed by 97 physicians affiliated with the Polish Society of Pediatric Nephrology. Women comprised 75.3%, with median time of professional experience in the study group was 15 years. RESULTS: A high level of emotional exhaustion, depersonalization, and reduced feeling of personal accomplishments were observed in 39.2%, 38.1%, and 21.6% of the participants, respectively. At least a medium level of burnout in all three dimensions were observed in 26.8% of the participants and 8.2% of them presented high three-dimensional burnout. About 41.2% of the participants stated that they would like to take part in burnout prevention and support programs. According to the study participants, excessive bureaucracy in healthcare systems, rush at work, and overtime work were the main job-related problems that could influence burnout intensity. CONCLUSIONS: Burnout is an important factor in the professional landscape of pediatric nephrology. Actions aimed at reducing the risk of occupational burnout among pediatric nephrologists should be applied, both at the personal and institutional levels.

Interfamilial clinical variability in four Polish families with cranioectodermal dysplasia and identical compound heterozygous variants in WDR35.

Cranioectodermal dysplasia (CED) is a rare autosomal recessive disorder primarily characterized by craniofacial, skeletal, and ectodermal abnormalities. CED is a chondrodysplasia, which is part of a spectrum of clinically and genetically heterogeneous diseases that result from disruptions in cilia. Pathogenic variants in genes encoding components of the ciliary transport machinery are known to cause CED. Intra- and interfamilial clinical variability has been reported in a few CED studies and the findings of this study align with these observations. Here, we report on five CED patients from four Polish families with identical compound heterozygous variants [c.1922T>G p.(Leu641Ter) and c.2522A>T; p.(Asp841Val)] in WDR35. The frequent occurrence of both identified changes in Polish CED families suggests that these variants may be founder mutations. Clinical evaluation of the CED patients revealed interfamilial clinical variability among the patients. This includes differences in skeletal and ectodermal features as well as variability in development, progression, and severity of renal and liver insufficiency. This is the first report showing significant interfamilial clinical variability in a series of CED patients from unrelated families with identical compound heterozygous variants in WDR35. Our findings strongly indicate that other genetic and non-genetic factors may modulate the progression and expression of the patients' phenotypes.

A single-center study to evaluate the efficacy of a fetal urine peptide signature predicting postnatal renal outcome in fetuses with posterior urethral valves.

BACKGROUND: Posterior urethral valves (PUVs) account for 17% of pediatric renal failure. The management of pregnancies involving fetuses with PUV is hampered by the fact that current clinical parameters obtained from fetal ultrasound and/or fetal urine biochemistry are insufficient to predict postnatal renal function. We previously have developed a fetal urine peptide signature (12PUV) that predicted with high precision postnatal renal failure at 2 years of age in fetuses with PUV. Here, we evaluated the accuracy of this signature to predict postnatal renal outcome in fetuses with PUV in an independent single-center study. METHODS: Thirty-three women carrying fetuses with suspected PUV were included. Twenty-five fetuses received vesicoamniotic shunts during pregnancy. PUV was confirmed postnatally in 23 patients. Of those 23 fetuses, 2 were lost in follow-up. Four and 3 patients died in the pre- and perinatal periods, respectively. Follow-up renal function at 6 months of age was obtained for the remaining 14 patients. The primary outcome was early renal failure, defined by an eGFR < 60 mL/min/1.73 m2 before 6 months of age or pre- or perinatal death. RESULTS: The peptide signature predicted postnatal renal outcome in postnatally confirmed PUV fetuses with an AUC of 0.94 (95%CI 0.74-1.0) and an accuracy of 90% (95%CI 78-100). The signature predicted postnatal renal outcome for the suspected PUV cases with an AUC of 0.89 (95%CI 0.72-0.97) and an accuracy of 84% (95%CI 71-97). CONCLUSIONS: This single-center study confirms the predictive power of the previously identified 12PUV fetal urinary peptide signature.

"Apple does not fall far from the tree" - subclinical atherosclerosis in children with familial hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) increases the risk of atherosclerosis in children and adults. Atherosclerotic cardiovascular disease in young patients FH is usually subclinical but recognition of children with more pronounced changes is crucial for adjusting effective management. Aim of this research was to use ultrasonography with two-dimensional speckle tracking (2DST) and tonometry to evaluate atherosclerotic changes in patients with FH (parents and their offspring). METHODS: Applanation tonometry and carotid arteries sonography with evaluation of the intima-media complex thickness (IMCT) and application of the 2DST were performed in 20 families with FH (20 parents and 29 children). The same size control group (age and sex matched) was included. Results were compared between peers and between generations together with the correlation analysis. RESULTS: Adults with FH, in comparison with healthy peers, presented significantly more atherosclerotic plaques (9 vs. 2, p = 0.0230), had significantly thicker IMC (0.84 ± 0.19 vs. 0.56 ± 0.06 mm, p < 0.0001) and had stiffer arterial wall (for stain: 6.25 ± 2.3 vs. 8.15 ± 2.46, p = 0.0103). In children from both groups there were no atherosclerotic plaques and IMCT did not differ significantly (0.42 ± 0.07 vs. 0.39 ± 0.04, p = 0.1722). However, children with FH had significantly stiffer arterial wall according to 2DST (for strain: 9.22 ± 3.4 vs. 11.93 ± 3.11, p = 0.0057) and tonometry (for the pulse wave velocity: 4.5 ± 0.64 vs.3.96 ± 0.62, p = 0.0047). These parameters correlated with atherosclerosis surrogates in their parents (p < 0.001) but were not significantly affected by presence of presumed pathogenic gene variant. CONCLUSIONS: Children with FH presented subclinical atherosclerosis manifested as decreased arterial wall elasticity. Degree of stiffening was associated with advancement of atherosclerosis in their parents but did not present significant association with gene variants. Sonography with application of 2DST seems to be a good candidate for comprehensive evaluation of atherosclerosis in families with FH.

Complete genome sequences of Aeromonas and Pseudomonas phages as a supportive tool for development of antibacterial treatment in aquaculture.

BACKGROUND: Aquaculture is the fastest growing sector of food production worldwide. However, one of the major reasons limiting its effectiveness are infectious diseases among aquatic organisms resulting in vast economic losses. Fighting such infections with chemotherapy is normally used as a rapid and effective treatment. The rise of antibiotic resistance, however, is limiting the efficacy of antibiotics and creates environmental and human safety concerns due to their massive application in the aquatic environment. Bacteriophages are an alternative solution that could be considered in order to protect fish against pathogens while minimizing the side-effects for the environment and humans. Bacteriophages kill bacteria via different mechanisms than antibiotics, and so fit nicely into the 'novel mode of action' concept desired for all new antibacterial agents. METHODS: The bacteriophages were isolated from sewage water and characterized by RFLP, spectrum of specificity, transmission electron microscopy (TEM) and sequencing (WGS). Bioinformatics analysis of genomic data enables an in-depth characterization of phages and the choice of phages. This allows an optimised choice of phage for therapy, excluding those with toxin genes, virulence factor genes, and genes responsible for lysogeny. RESULTS: In this study, we isolated eleven new bacteriophages: seven infecting Aeromonas and four infecting Pseudomonas, which significantly increases the genomic information of Aeromonas and Pseudomonas phages. Bioinformatics analysis of genomic data, assessing the likelihood of these phages to enter the lysogenic cycle with experimental data on their specificity towards large number of bacterial field isolates representing different locations. CONCLUSIONS: From 11 newly isolated bacteriophages only 6 (25AhydR2PP, 50AhydR13PP, 60AhydR15PP, 22PfluR64PP, 67PfluR64PP, 71PfluR64PP) have a potential to be used in phage therapy due to confirmed lytic lifestyle and absence of virulence or resistance genes.

Two-Dimensional Speckle Tracking Versus Applanation Tonometry in Evaluation of Subclinical Atherosclerosis in Children with Type 1 Diabetes Mellitus.

BACKGROUND Patients with type 1 diabetes mellitus (T1DM) often develop atherosclerosis at an early age. In the subclinical stage of the process, minimal/non-morphological changes can be noticed, but the arterial wall function can be impaired. Applanation tonometry allows to assess the arterial tree stiffness; however, the Two-Dimensional Speckle Tracking (2DST) is an increasingly accepted alternative. This study evaluated arterial wall stiffness using these 2 techniques in children with T1DM. MATERIAL AND METHODS We performed applanation tonometry and carotid arteries sonography with evaluation of the carotid intima-media thickness (cIMT) and use of the 2DST in 50 children with T1DM and in 50 healthy sex- and age-matched controls. We also assessed the reliability of 2DST in 10 random subjects. RESULTS Children with T1DM had increased arterial wall stiffness, which was confirmed by tonometry (PWV: p=0.0386) and 2DST (Strain: p=0.0004; Strain rate: p=0.0081). There was no significant difference in cIMT between groups (0.45±0.06 vs. 0.43±0.05, p=0.073 in children with T1DM and controls, respectively). 2DST presented good intraclass correlation coefficient between researchers and within a single researcher. CONCLUSIONS Children with T1DM presenting with subclinical stage of atherosclerosis were found to have arterial wall stiffening. The 2DST, the same as applanation tonometry, allows to recognize this condition but in a more accessible and reproducible manner.

Risk Factors for Early Dialysis Dependency in Autosomal Recessive Polycystic Kidney Disease.

OBJECTIVE: To identify prenatal, perinatal, and postnatal risk factors for dialysis within the first year of life in children with autosomal recessive polycystic kidney disease (ARPKD) as a basis for parental counseling after prenatal and perinatal diagnosis. STUDY DESIGN: A dataset comprising 385 patients from the ARegPKD international registry study was analyzed for potential risk markers for dialysis during the first year of life. RESULTS: Thirty-six out of 385 children (9.4%) commenced dialysis in the first year of life. According to multivariable Cox regression analysis, the presence of oligohydramnios or anhydramnios, prenatal kidney enlargement, a low Apgar score, and the need for postnatal breathing support were independently associated with an increased hazard ratio for requiring dialysis within the first year of life. The increased risk associated with Apgar score and perinatal assisted breathing was time-dependent and vanished after 5 and 8 months of life, respectively. The predicted probabilities for early dialysis varied from 1.5% (95% CI, 0.5%-4.1%) for patients with ARPKD with no prenatal sonographic abnormalities to 32.3% (95% CI, 22.2%-44.5%) in cases of documented oligohydramnios or anhydramnios, renal cysts, and enlarged kidneys. CONCLUSIONS: This study, which identified risk factors associated with onset of dialysis in ARPKD in the first year of life, may be helpful in prenatal parental counseling in cases of suspected ARPKD.

CoQ10-related sustained remission of proteinuria in a child with COQ6 glomerulopathy-a case report.

BACKGROUND: Treatment of steroid resistant nephrotic syndrome is still a challenge for physicians. There are a growing number of studies exploring genetic background of steroid-resistant glomerulopathies. CASE DIAGNOSIS/TREATMENT: We present the case of a 4-year-old girl with steroid-resistant glomerulopathy due to a COQ6 defect with no additional systemic symptoms. The disease did not respond for second-line therapy with calcineurin inhibitor, but it remitted completely after oral treatment with 30 mg/kg/d of coenzyme Q10 (CoQ10). The patient was identified to be a compound heterozygote for two pathogenic variants in COQ6 gene: a known missense substitution c.1078C > T (p.R360W) and a novel frameshift c.804delC mutation. After 12 months of CoQ10 therapy, the child remains in full remission, her physical development accelerated, frequent respiratory airways diseases subsided. CONCLUSIONS: Genetic assessment of children with steroid-resistant nephrotic proteinuria enables therapy optimization. Proteinuria caused by a COQ6 gene defect can be successfully treated with CoQ10.

What has changed in the prevalence of hypertension in dialyzed children during the last decade?

BACKGROUND: Hypertension very often accompanies progression of chronic kidney disease (CKD) in children. A cross-sectional analysis of hypertension prevalence in dialyzed children in Poland was designed with a comparison with the data previously recorded 10 years earlier. METHODS: Two cohorts of children were analyzed: 59 subjects dialyzed in 2013, and 134 children from the previous study performed in 2003 that were reevaluated according to the current methodology. The incidence of hypertension (defined by SDS of sBP or dBP >1.64), clinical data, medical history, dialysis modalities and selected biochemical parameters of dialysis adequacy were analyzed. RESULTS: The prevalence of hypertension increased from 64% in 2003 to 78% in 2013. The efficacy of antihypertensive treatment remained unsatisfactory (61% proper BP control). Preservation of residual urine output and strict fluid balance may prevent development of hypertension in children on dialysis. CONCLUSIONS: Despite the higher awareness of hypertension and its complications in dialyzed children, the incidence of this entity has increased during the last decade, with the percentage of undertreated patients comparable to that observed 10 years ago. Thus, more attention should be paid to therapy efficacy in this population to prevent further damage to the cardiovascular system and to decrease morbidity.

Lead enhances fluoride influence on apoptotic processes in the HepG2 liver cell line.

Chronic long-term exposure to high levels of fluoride leads to fluorosis, manifested by skeletal fluorosis and damage to internal organs, including kidneys, liver, parathyroid glands, and brain. Excess fluoride can also cause DNA damage, trigger apoptosis, and change cell cycle. The effect of fluoride may be exacerbated by lead (Pb), a potent inhibitor of many enzymes and a factor causing apoptosis, still present in the environment in excessive amounts. Therefore, in this study, we investigated the effects of sodium fluoride (NaF) and/or lead acetate (PbAc) on development of apoptosis, cell vitality, and proliferation in the liver cell line HepG2. We examined hepatocytes from the liver cell line HepG2, incubated for 48 h with NaF, PbAc, and their mixture (NaF + PbAc), and used for measuring apoptosis, index of proliferation, and vitality of cells. Incubation of the hepatocytes with NaF or PbAc increased apoptosis, more when fluoride and Pb were used simultaneously. Vitality of the cells depended on the compound used and its concentration. Proliferation slightly increased and then decreased in a high fluoride environment; it decreased significantly after addition of Pb in a dose-dependent manner. When used together, fluoride inhibited the decreasing effect of Pb on cell proliferation.

Are the Classical Symptoms of Hypertension in Children Still Sensitive Enough?

The available literature is scarce on the initial symptoms of arterial hypertension in children. Our study aimed to analyze the initial clinical profile of patients referred to the hospital with suspected hypertension and those diagnosed with hypertension for the first time during a hospitalization for other reasons. This study was a retrospective analysis of medical records in 471 patients. More than half of the patients showed no symptoms. The most common symptom reported was a headache-28% (132) of patients. The diagnosis of elevated blood pressure or hypertension was more frequent in asymptomatic patients (P = 0.001). Headaches were seen more often in healthy patients than in patients with hypertension. Newly diagnosed hypertension is mainly diagnosed in asymptomatic children. Moreover, the symptoms previously described in the literature as the most common did not prove to be predictive of hypertension in our study.

Evaluation of oxidative stress markers in pathogenesis of diabetic neuropathy.

Experimental evidences suggest that hyperglycaemia-induced overproduction of reactive oxygen species and subsequent damage to proteins, lipids and DNA may play a key role in the development of distal symmetric polyneuropathy (DSPN)-the most common complication of diabetes mellitus. The study population consisted of 51 individuals aged 52-82 years classified into 3 groups: 16 patients diagnosed with type 2 diabetes mellitus (T2DM) with DSPN, 16 T2DM patients without DSPN and 19 control subjects without diabetes and neuropathy. The study was conducted to determine the activity of antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX) and total antioxidant status (TAS) in the examined groups. An alkaline comet assay was used to determine the extent of DNA damage of oxidized purines as glicosylo-formamidoglicosylase (Fpg) sites, and oxidized pyrimidines as endonuclease III (Nth) sites. A significant decrease of SOD (P < 0.05), GPX (P < 0.05) and nonsignificant decrease of CAT (P > 0.05), and TAS status (P > 0.05) were seen in T2DM patients with neuropathy compared to T2DM patients as well as controls. T2DM patients with or without neuropathy revealed significantly lower (P < 0.05) plasma concentration of nitrous oxide compared to the control subjects. Endogenous level of oxidative DNA damage in T2DM patients with DSPN was significantly higher compared both to the controls and T2DM patients without DSPN (P < 0.001). Moreover, lymphocytes isolated from T2DM patients with DSPN were more susceptible to oxidative DNA lesions induced by hydrogen peroxide than from T2DM patients without DSPN (P < 0.001). Our results confirm hypothesis that oxidative stress may play a substantial role in the development and progression of diabetic distal symmetric polyneuropathy.