Antioxidants inhibition of high plasma androgenic markers in the pathogenesis of ethylene glycol (EG)-induced nephrolithiasis in Wistar rats

Oxidized forms of uromodulin promote calcium oxalate crystallization and growth, but not aggregation

Roles of an abundant human urinary protein, uromodulin (UMOD), in kidney stone disease were previously controversial. Recently, we have demonstrated that oxidative modification reverses overall modulatory activity of whole urinary proteins, from inhibition to promotion of calcium oxalate (CaOx) stone-forming processes. We thus hypothesized that oxidation is one of the factors causing those previously controversial UMOD data on stone modulation. Herein, we addressed effects of performic-induced oxidation on CaOx crystal modulatory activity of UMOD. Sequence analyses revealed two EGF-like calcium-binding domains (65th-107th and 108th-149th), two other calcium-binding motifs (65th-92nd and 108th-135th), and three oxalate-binding motifs (199th-207th, 361st-368th and 601st-609th) in UMOD molecule. Analysis of tandem mass spectrometric dataset of whole urinary proteins confirmed marked increases in oxidation, dioxidation and trioxidation of UMOD in the performic-modified urine samples. UMOD was then purified from the normal urine and underwent performic-induced oxidative modification, which was confirmed by Oxyblotting. The oxidized UMOD significantly promoted CaOx crystallization and crystal growth, whereas the unmodified native UMOD inhibited CaOx crystal growth. However, the oxidized UMOD did not affect CaOx crystal aggregation. Therefore, our data indicate that oxidized forms of UMOD promote CaOx crystallization and crystal growth, which are the important processes for CaOx kidney stone formation.

Diet-Derived Antioxidants and Risk of Kidney Stone Disease: Results From the NHANES 2007-2018 and Mendelian Randomization Study

We aimed to explore the associations between diet-derived antioxidants and kidney stone disease (KSD) risk in this study. We performed weighted multivariable-adjusted logistic regression to assess the associations between the six main diet-derived antioxidants and the risk of KSD by using data from the National Health and Nutrition Examination Survey (NHANES) 2007–2018. Then, we used the Mendelian randomization (MR) approach to verify the causal relationships between circulating antioxidants levels and KSD risk. Genetic tools were extracted from published genome-wide association studies (GWAS). Summary data for KSD was from the FinnGen study and UK biobank. Inverse variance weighted (IVW) was the primary analysis. The 26,438 participants, including 2,543 stone formers, were included for analyses. There were no significant associations between retinol, vitamin B6, vitamin C, vitamin E, and lycopene intake with the risk of KSD across all the quartile categories. Similarly, pooled odds ratio (OR) for KSD risk in genetically predicted per unit change were 1.25 (95% CI: 0.39, 4.02; p = 0.712), 1.14 (95% CI: 0.84, 1.53; p = 0.400), 0.75 (95% CI: 0.52, 1.10; p = 0.141), 1.66 (95% CI: 0.80, 3.46; p = 0.178), 1.27 (95% CI: 0.29, 5.62; p = 0.756), and 0.92 (95% CI: 0.76, 1.12; p = 0.417) for retinol, β-carotene, vitamin B6, vitamin C, α-tocopherol, and lycopene, respectively. The above estimates were replicated in the secondary analyses using UK biobank data. Our study did not support a causal association between circulating antioxidants levels and KSD risk. However, these findings should be verified in larger sample-size MR due to the pleiotropy and other limitations.

Genetic Variations rs859, rs4646, and rs372883 in the 3'-Untranslated Regions of Genes Are Associated with a Risk of IgA Nephropathy

BACKGROUND

Previous studies indicate that genetic factors play an important role in the pathogenesis of IgA nephropathy (IgAN). To evaluate the association between single nucleotide polymorphisms (SNPs) in the 3'-untranslated region (3'-UTR) of genes and IgAN risk, we performed a case-control study in a Chinese Han population.

MATERIALS

Twelve SNPs were selected and genotyped in 384 IgAN patients and 357 healthy controls. Odds ratio (OR) and 95% confidence intervals (CI) were calculated by logistic regression adjusted for age and gender. Multifactor dimensionality reduction (MDR) was used to analyze the interaction of SNP-SNP with IgAN risk.

RESULTS

Our study demonstrated that IL-16 rs859 (OR = 0.75, p = 0.040) and CYP19A1 rs4646 (OR = 2.58, p = 0.017) polymorphism were related to the risk of IgAN. In stratified analyses by gender, CYP19A1 rs4646 (OR = 2.96, p = 0.015) and BACH1 rs372883 (OR = 1.81, p = 0.038) polymorphisms conferred susceptibility to IgAN in males. Besides, rs372883 reduced IgAN risk in females (OR = 0.44, p = 0.042). We also found rs859 polymorphism was correlated with grade I-II (OR = 0.42, p = 0.028) in subgroup analysis of Lee's classification. Additionally, we found rs4646 polymorphism was correlated with serum creatinine (p = 0.035).

CONCLUSION

Our results suggested that the IL-16 rs859, CYP19A1 rs4646, and BACH1 rs372883 polymorphisms have potential roles in the genetic susceptibility to IgAN in Chinese Han population.

Protective effects of boron and vitamin E on ethylene glycol-induced renal crystal calcium deposition in rat

Objectives. Kidney stone disease is a common form of renal disease. Antioxidants, such as vitamin E (Vit E) and boron, are substances that reduce the damage caused by oxidation.

Methods. Adult male rats were divided into 5 groups (n=6). In group 1, rats received standard food and water for 28 days (control group); in group 2, standard rodent food and water with 0.75% ethylene glycol/d (dissolved in drinking water) (EG Group); in group 3, similar to group 2, with 3 mg of boron/d (dissolved in water) (EG+B Group); in group 4, similar to group 2, with 200 IU of vitamin E injected intraperitoneally on the first day and the 14th day, (EG+Vit E Group); in group 5, mix of groups 3 and 4, respectively (EG+B+Vit E Group).

Results. Kidney sections showed that crystals in the EG group increased significantly in comparison with the control group. Crystal calcium deposition score in groups of EG+B (160), EG+Vit E, and EG+B+Vit E showed a significant decrease compared to EG group. Measurement of the renal tubules area and renal tubular epithelial histological score showed the highest significant dilation in the EG group. Tubular dilation in the EG+B+Vit E group decreased compared to the EG+B and EG+Vit E groups.

Conclusions. Efficient effect of boron and Vit E supplements, separately and in combination, has a complimentary effect in protection against the formation of kidney stones, probably by decreasing oxidative stress.

Possible role of elevated serum testosterone in pathogenesis of renal stone formation

Background:

Urolithiasis or renal stone formation occurs with three times higher frequency in males and decreases with age in parallel with the serum testosterone levels, suggesting a role played by male sex hormones. Androgens appear a promotion action and estrogens an inhibitory action on kidney stone formation in several animal models suggesting a study to be carried out to deduce the role played by serum testosterone in the formation of renal stones.

Aim:

The aim of this study is to define the involvement of serum total testosterone, free testosterone, and dihydrotestosterone in the pathogenesis of urolithiasis in males by comparing the results with healthy males with no present or past history of urolithiasis as controls.

Materials and Methods:

A case–control study was undertaken with 108 participants: 78 males diagnosed with urolithiasis and 30 age-matched healthy males.

Results:

The difference between mean age and body mass index of patients and controls were found to be nonsignificant. The total serum testosterone levels, serum dihydrotestosterone levels, were found to be higher in patients when compared to controls, and the difference was found to be significant. The levels of free testosterone and serum estradiol were also found to be higher in urolithiatic patients.

Conclusion:

The study demonstrates that elevated levels of serum testosterone and serum dihydrotestosterone might be involved in increased incidences of stone formation. The higher levels of estradiol do not seem to be a protective factor in males with urolithiasis with higher serum testosterone levels.

Androgens involvement in the pathogenesis of renal stones formation

OBJECTIVE

The potential role for the gonadal steroids in the pathogenesis of urolithiasis, higher mean of plasma oxalate concentration and kidney calcium oxalate deposition influenced by androgens in men has been proposed. In this study, the serum levels of steroid hormones as a pathogenesis of this condition in male patients with active renal stone disease compared with controls was investigated.

METHODS

Forty patients diagnosed with renal stones and hospitalized for further clinical treatments or referred to our office after ultrasonographic evaluations participated in the study. Forty six healthy subjects served as controls. Steroid sex hormones in the plasma samples including testosterone, free testosterone, dihydrotestosterone, estradiol, and sex hormone binding globulin were analyzed.

RESULTS

A significant difference was observed between patients and the control subjects regarding serum testosterone, free testosterone, dihydrotestosterone, estradiol, and sex hormone binding globulin.

CONCLUSIONS

Based on the results, a higher androgens level was diagnosed in renal stone patients, indicating a possibility of a substantial pathogenic role of testosterone, free testosterone, and dihydrotestosterone involvement in the pathogenesis of renal stones formation. Therefore, data presentation and further investigation on the relation between male steroids and urolithiasis is of importance and should be considered in evaluation of the etiology of the disease.