Implications of oxidative stress in the pathophysiology of obstructive uropathy

Effects of upadacitinib and PD29 on oxidative damage and inflammation in bleomycin-induced scleroderma model kidney tissues

Objective: Scleroderma (SSc) is a rare autoimmune tissue disease. There is currently no effective treatment for SSc. The aim of this study was to investigate the antioxidant and anti-inflammatory effects of upadacitinib and PD29 on total oxidant status (TOS), total antioxidant status (TAS), malondialdehyde (MDA), catalase (CAT), glutathione (GSH) peroxidase levels, and interleukin-6 (IL-6) and interleukin-13 ( IL-13) in kidney tissues of an experimental SSc model. Materials and Methods: The experimental design was established with five groups of eight mice: Control, bleomycin (BLM) (5 μg/kg), BLM + upadacitinib (3mg/kg), BLM + PD29 (5 mg/kg) and BLM + PD29 + upadacitinib group. BLM was administered subcutaneously once a day for 21 days. PD29 was administered subcutaneously and upadacitinib (gavage) were injected for 21 days. Renal tissues were collected at the end of the experiment. Renal TOS, TAS, MDA, CAT, GSH levels, and IL-6 and IL-13 gene expressions were evaluated. Results: Upadacitinib and PD29 affected oxidant status and TOS. MDA levels decreased, and GSH, CAT, and TAS levels increased. Also, upadacitinib and PD29 decreased inflammation via IL-6 and IL-13 cytokines. Conclusion: Upadacitinib and PD29 may have therapeutic roles for SSc renal crisis.

The causal association between smoking, alcohol consumption and risk of upper urinary calculi: insights from a Mendelian randomization study

Background: The causal link between smoking, alcohol consumption, and upper urinary calculi remains uncertain in observational studies due to confounding factors. To uncover potential causal associations, we utilized two-sample univariable and multivariable Mendelian randomization (MR) methods. Methods: Five risk factors related to lifestyles (cigarettes per day, lifetime smoking index, smoking initiation, drinks per week and alcohol intake frequency) were chosen from the Genome-Wide Association Study (GWAS). Upper urinary calculi were obtained from the FinnGen and United Kingdom Biobank consortium. Inverse-variance-weighted (IVW) was mainly used to compute odds ratios (OR) and 95% confidence intervals (Cl). While diligently scrutinizing potential sources of heterogeneity and horizontal pleiotropy via the rigorous utilization of Cochran's Q test, the MR-PRESSO method, and MR-Egger. Results: The summary OR for upper urinary calculi was 0.6 (IVW 95% CI: 0.49-0.74; p = 1.31 × 10-06) per standard deviation decrease in drinks per week. Interestingly, the genetically predicted alcohol intake frequency was associated with a significantly increased risk upper urinary calculi (OR = 1.27; 95% CI: 1.11-1.45; p = 0.0005). Our study found no association between smoking initiation, the number of cigarettes per day, and the lifetime smoking index and the risk of upper urinary calculi. By adjusting for body mass index and education, estimates of drinks per week remained consistent in multivariate MR analyses, while alcohol intake frequency became non-significant. Conclusion: MR analysis showed that drinks per week was negatively associated with upper urinary calculi, whereas the effect of tobacco on upper urinary calculi was not significant and the detrimental effect of alcohol intake frequency on upper urinary calculi became non-significant after adjusting for BMI and education.

Univariable and multivariable mendelian randomization study revealed the modifiable risk factors of urolithiasis

BACKGROUND

Urolithiasis is a common urological disease with increasing incidence worldwide, and preventing its risk poses significant challenges. Here, we used Mendelian randomization (MR) framework to genetically assess the causal nature of multifaceted risk factors on urolithiasis.

METHODS

17 potential risk factors associated with urolithiasis were collected from recently published observational studies, which can be categorized basically into lifestyle factors and circulating biomarkers. The instrumental variables of risk factors were selected from large-scale genome-wide association studies (N ≤ 607,291). Summary-level data on urolithiasis were obtained from UK Biobank (UKB) (3,625 cases and 459,308 noncases) and the FinnGen consortium (5,347 cases and 213,445 noncases). The univariable and multivariable MR analyses were applied to evaluate the causal, independent effect of these potential risk factors upon urolithiasis. Effects from the two consortia were combined by the meta-analysis methods.

RESULTS

Higher genetically predicted sex hormone-binding globulin (SHBG, OR, 0.708; 95% CI, 0.555 to 0.903), estradiol (OR, 0.179; 95% CI, 0.042 to 0.751), tea intake (OR, 0.550; 95% CI, 0.345 to 0.878), alcoholic drinks per week (OR, 0.992; 95% CI, 0.987 to 0.997), and some physical activity (e.g., swimming, cycling, keeping fit, and bowling, OR, 0.054; 95% CI, 0.008 to 0.363) were significantly associated with a lower risk of urolithiasis. In the Multivariate Mendelian Randomization (MVMR) analyses, the significant causal associations between estradiol, SHBG, tea intake, and alcoholic drinks per week with urolithiasis were robust even after adjusting for potential confounding variables. However, the previously observed causal association between other exercises and urolithiasis was no longer significant after adjusting for these factors.

CONCLUSIONS

The univariable and multivariable MR findings highlight the independent and significant roles of estradiol, SHBG, tea intake, and alcoholic drinks per week in the development of urolithiasis, which might provide a deeper insight into urolithiasis risk factors and supply potential preventative strategies.

Association between alcohol and urolithiasis: a mendelian randomization study

The causal relationship between alcohol and urolithiasis remains uncertain, despite previous observational studies reporting an association between the two. To determine the causality, we conducted a two-sample Mendelian randomization (MR) analysis. In this study, we aimed to investigate the causal relationship between alcohol and kidney stones using a two-sample MR approach. Two sets of genetic instruments were utilized in the analysis, both of which were derived from publicly available genetic summary data. The first set consisted of 73 single-nucleotide polymorphisms (SNPs) robustly linked to alcohol intake frequency (AIF) and the second set was comprised of 69 SNPs associated with alcohol consumption (AC). Our MR analysis was performed using several methods including the inverse-variance weighted (IVW) method, weighted median method, MR-Egger regression, MR Pleiotropy RESidual Sum and Outlier test. Our results from the MR analysis revealed a borderline significant association between AIF and the risk of urolithiasis. This was established through the use of the IVW method (OR (95% CI) = 1.29 (1.02, 1.65), p = 0.036) and the weighted median approach (OR (95% CI) = 1.44 (1.10, 1.89), p = 0.008). The MR-Egger model also yielded similar risk estimates (OR (95% CI) = 1.39 (0.66, 2.93), p = 0.386), although the relationship was not statistically significant. Sixty-eight SNPs were identified as having a substantial and independent link with AC. However, the IVW approach revealed no significant effect of AC on the risk of urolithiasis (OR (95% CI) = 0.74 (0.48, 1.14), p = 0.173). The MR analysis suggested a potential causal association between alcohol intake frequency and the risk of urolithiasis, but not alcohol consumption.

Short-term effects of ambient air pollution on emergency department visits for urolithiasis: A time-series study in Wuhan, China

Background

Previous studies have explored the correlation between short-term exposure to air pollution and urinary system diseases, but lack of evidence on the correlation between air pollution and urolithiasis.

Methods

Daily data of emergency department visits (EDVs), concentrations of six air pollutants (SO₂, NO₂, PM_2.5, PM₁₀, CO, and O₃) and meteorological variables were collected in Wuhan, China, from 2016 to 2018. And a time-series study was conducted to investigate short-term effects of air pollutants on urolithiasis EDVs. In addition, stratified analyses by season, age and gender were also conducted.

Results

A total of 7,483 urolithiasis EDVs were included during the study period. A 10-μg/m³ increase of SO₂, NO₂, PM_2.5, CO, PM₁₀, and O₃ corresponded to 15.02% (95% confidence interval [CI]: 1.69%, 30.11%), 1.96% (95% CI: 0.19%, 3.76%), 1.09% (95% CI:-0.24%, 2.43%), 0.14% (95% CI: 0.02%, 0.26%), 0.72% (95% CI: 0.02%, 1.43%), and 1.17% (95% CI: 0.40%, 1.94%) increases in daily urolithiasis EDVs. Significant positive correlations were observed between SO₂, NO₂, CO, and O₃ and urolithiasis EDVs. The correlations were mainly among females (especially PM_2.5 and CO) and younger people (especially SO₂, NO₂, and PM₁₀) but the effect of CO was more obvious in elders. Furthermore, the effects of SO₂ and CO were stronger in warm seasons, while the effects of NO₂ were stronger in cool seasons.

Conclusion

Our time-series study indicates that short-term exposure to air pollution (especially SO₂, NO₂, CO, and O₃) was positively correlated with EDVs for urolithiasis in Wuhan, China, and the effects varied by season, age and gender.

Hydrogen-rich water reduced oxidative stress and renal fibrosis in rats with unilateral ureteral obstruction

BACKGROUND

Congenital obstructive nephropathy (CKD) is commonly implicated in the pathophysiology of chronic kidney disease occurring in the pediatric and adolescent age groups and the release of reactive oxygen species contribute to the worsening of renal fibrosis. Molecular hydrogen (H₂) protects against tissue injury by reducing oxidative stress. We evaluated the efficacy of oral H₂-rich water (HW) intake in preventing unilateral ureteral obstruction (UUO)-induced renal injury in rats.

METHODS

Male Sprague-Dawley UUO or control rats were administered with distilled water (DW) or HW for 2 weeks post-surgery. Histopathological and immunohistochemical analyses of kidney samples were performed.

RESULTS

Histological changes were not apparent in the sham-operated kidneys. However, UUO kidneys were found to have widened interstitial spaces and tubular dilatation. Compared with the UUO + DW group, HW administration attenuated tubulointerstitial injury and reduced interstitial fibrotic area, causing a substantial decline in the frequency of α-SMA-, ED-1-, and TGF-β1-positive cells in the UUO + HW group. The decrease in the klotho mRNA expression in the UUO + HW group was less pronounced than that in the UUO + DW group.

CONCLUSION

Oral HW intake reduced oxidative stress and prevented interstitial fibrosis in UUO kidneys, potentially involving klotho in the underlying mechanism.

IMPACT

Oral intake of hydrogen-rich water (HW) can reduce oxidative stress and suppress interstitial fibrosis in unilateral ureteral obstruction-induced renal injury in rats. This mechanism possibly involves klotho, which is known for its antiaging roles. The association between molecular hydrogen and klotho in renal fibrosis is well known; this is the first report on the association in a unilateral ureteral obstruction model. Drinking HW is a safe and convenient treatment for oxidative stress-induced pathologies, without side effects. As a prospect for future research, oral HW intake to treat oxidative stress may improve renal fibrosis in congenital obstructive nephropathy.

Obesity-related indices and its association with kidney stone disease: a cross-sectional and longitudinal cohort study

Obesity increases the risk of several diseases, including kidney stone disease (KSD). The study aimed to explore the relationship between KSD and various obesity-related indices. A total of 121,605 participants in the Taiwan Biobank from December 2008 to February 2020 were analyzed. The association between self-reported history of KSD and eight obesity-related indices, including body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), waist-to-hip ratio (WHR), abdominal volume index (AVI), body roundness index (BRI), conicity index, and triglyceride glucose index was examined in cross-sectional analysis; additionally, the risk of developing kidney stones was analyzed in a longitudinal cohort of 25,268 participants without KSD at baseline, which was a subset of the main cohort. Of all participants, 77,904 (64.1%) were female. Overall, 10.7% of males and 4.0% of females had KSD. Multivariate-adjusted logistic regression showed that all obesity-related indices were significantly associated with KSD. During a mean follow-up of 47 months, kidney stones occurred in 642 (2.5%) participants, and after adjusting for confounders, the risk of developing kidney stones was higher in participants with higher BMI, WC, WHtR, WHR, AVI and BRI. BMI, WC, WHtR, WHR, AVI, and BRI were found to be associated with a higher prevalence of kidney stones as well as development of incident kidney stones, which could be used as predictive factors for development of KSD in clinical practice.

Caffeic Acid, One of the Major Phenolic Acids of the Medicinal Plant Antirhea borbonica, Reduces Renal Tubulointerstitial Fibrosis

The renal fibrotic process is characterized by a chronic inflammatory state and oxidative stress. Antirhea borbonica (A. borbonica) is a French medicinal plant found in Reunion Island and known for its antioxidant and anti-inflammatory activities mostly related to its high polyphenols content. We investigated whether oral administration of polyphenol-rich extract from A. borbonica could exert in vivo a curative anti-renal fibrosis effect. To this aim, three days after unilateral ureteral obstruction (UUO), mice were daily orally treated either with a non-toxic dose of polyphenol-rich extract from A. borbonica or with caffeic acid (CA) for 5 days. The polyphenol-rich extract from A. borbonica, as well as CA, the predominant phenolic acid of this medicinal plant, exerted a nephroprotective effect through the reduction in the three phases of the fibrotic process: (i) macrophage infiltration, (ii) myofibroblast appearance and (iii) extracellular matrix accumulation. These effects were associated with the mRNA down-regulation of Tgf-β, Tnf-α, Mcp1 and NfkB, as well as the upregulation of Nrf2. Importantly, we observed an increased antioxidant enzyme activity for GPX and Cu/ZnSOD. Last but not least, desorption electrospray ionization-high resolution/mass spectrometry (DESI-HR/MS) imaging allowed us to visualize, for the first time, CA in the kidney tissue. The present study demonstrates that polyphenol-rich extract from A. borbonica significantly improves, in a curative way, renal tubulointerstitial fibrosis progression in the UUO mouse model.

Do Lifestyle Factors Including Smoking, Alcohol, and Exercise Impact Your Risk of Developing Kidney Stone Disease? Outcomes of a Systematic Review

Introduction: With a rise in the incidence of stone disease, more research is needed to understand the lifestyle factors associated with it. We evaluate available evidence for association of smoking, alcohol, and exercise with kidney stone disease (KSD). Methods: A systematic literature search was conducted in CINAHL, EMBASE, Ovid Medline, Cochrane Library, Scopus, Clinicaltrials.gov, and Google Scholar. Different keywords were "smoking," "cigarette," "alcohol," "spirits," "exercise," "physical activity," "training," "kidney stone," "stone disease," "nephrolithiasis," "urolithiasis," "renal stone," and "urinary stone." The main outcome of interest was the role of smoking, alcohol, and exercise in the development of KSD. Results: A total of 4921 articles were found on searching the databases, of which 14 met the criteria for inclusion in the final review. Studies assessed the following risk factors, physical activity (n = 6), alcohol (n = 6), and smoking (n = 9), and included 17,511 patients. The relationship of physical activity with KSD appears to be equivocal. In addition, only one study demonstrated a decreased risk of nephrolithiasis with alcohol consumption. On the contrary, four studies found a significant association between smoking and renal stone formation. Conclusions: While smoking is one behavioral factor that seems to have some association with KSD, no clear effect of alcohol and physical activity has been demonstrated. To avoid KSD, awareness of the possible detrimental role of smoking should be considered and patients should remain vigilant about the importance of hydration with physical activity. While this represents the most appropriate guidance from the evidence available, at present there remain insufficient data to truly reveal the relationship between these three factors and KSD.

Evaluation of dynamic thiol-disulphide homeostasis in obstructive uropathy

PURPOSE

To evaluate the ability of thiol-disulphide homeostasis to predict renal injury in ureteral obstruction by matching renal scintigraphy and pathological findings in an experimental rat model.

METHODS

24 rats were randomized and divided into 3 groups as sham, partial and complete. Blood samples for biochemical evaluations and dimercaptosuccinic acid (DMSA) renal scintigraphy were performed at the beginning and on the 7th day postoperatively. Only a midline abdominal incision was done in sham group. Left ureter of partial group was dissected and gently buried into the psoas muscle. In complete group, left ureter was dissected and ligated.

RESULTS

Statistically significant association was found between left kidney function loss percentage, native thiol, total thiol and creatinine alterations and pathological EGTI (Endothelial, Glomerular, Tubular, Interstitial) scores (r = - 0.867, r = - 0.815, r = 0.745, r = - 0.911; p = 0.000). Statistically significant difference was detected between groups in terms of postoperative native thiol and total thiol values (p = 0.000, p = 0.001). There was also a significant difference in preoperative and postoperative comparisons of these parameters in partial and complete obstruction groups (p = 0.012, p = 0.018). There was a significant difference in terms of postoperative disulphide/native thiol and native thiol/total thiol ratios in complete obstruction group compared to other groups (p₁ = 0.011, p₂ = 0.040; p₁ = 0.015, p₂ = 0.028).

CONCLUSIONS

Association with scintigraphic and pathological results empowers the value of this parameter. Disulphide/native thiol and native thiol/total thiol ratios indicate complete obstruction. These findings may shed light to more comprehensive studies.

Hydrogen Rich Water Attenuates Renal Injury and Fibrosis by Regulation Transforming Growth Factor-β Induced Sirt1

The current research was designed to study the role of hydrogen in renal fibrosis and the renal epithelial to mesenchymal transition (EMT) induced by transforming growth factor-β1 (TGF-β1). Hydrogen rich water (HW) was used to treat animal and cell models. Unilateral ureteral obstruction (UUO) was performed on Balb/c mice to create a model of renal fibrosis. Human kidney proximal tubular epithelial cells (HK-2 cells) were treated with TGF-β1 for 36 h to induce EMT. Serum creatinine (Scr) and blood urea nitrogen (BUN) were measured to test renal function, in addition, kidney histology and immunohistochemical staining of alpha-smooth muscle actin (α-SMA) positive cells was performed to examine the morphological changes. The treatment with UUO induced a robust fibrosis of renal interstitium, shrink of glomerulus and partial fracture of basement membrane. Renal function was also impaired in the experimental group with UUO, with an increase of Scr and BUN in serum. After that, Western-blot was performed to examine the expression of α-SMA, fibronectin, E-cadherin, Smad2 and Sirtuin-1 (Sirt1). The treatment with HW attenuated the development of fibrosis and deterioration of renal function in UUO model. In HK-2 cells, the pretreatment of HW abolished EMT induced by TGF-β1. The down-regulation the expression of Sirt1 induced by TGF-β1 which was dampened by the treatment with HW. Sirtinol, a Sirt1 inhibitor, reversed the effect of HW on EMT induced by TGF-β1. HW can inhibit the development of fibrosis in kidney and prevents HK-2 cells from undergoing EMT which is mediated through Sirt1, a downstream molecule of TGF-β1.

MnTBAP therapy attenuates the downregulation of sodium transporters in obstructive kidney disease

Ureteral obstruction is associated with reduced expressions of renal sodium transporters, which contributes to impaired urinary concentrating capacity. In this study, we employed a synthetic mitochondrial superoxide dismutase 2 (SOD2) mimic MnTBAP to investigate the role of mitochondrial oxidative stress in modulating the sodium transporters in obstructive kidney disease. Following unilateral ureteral obstruction (UUO) for 7 days, a global reduction of sodium transporters including NHE3, NCC, NKCC2, and ENaCα was observed as determined by qRT-PCR, Western Blotting or immunohistochemistry. Among these sodium transporters, the downregulation of NHE3, NCC, and NKCC2 was partially reversed by MnTBAP treatment. In contrast, the reduction of ENaCα was not affected by MnTBAP. The β and γ subunits of ENaC were not significantly altered by ureteral obstruction or MnTBAP therapy. To further confirm the anti-oxidant effect of MnTBAP, we examined the levels of TBARs in the urine collected from the obstructed ureters of UUO mice and bladder of sham mice. As expected, the increment of urinary TBARs in UUO mice was entirely abolished by MnTBAP therapy, indicating an amelioration of oxidative stress. Meantime, we found that three types of SOD were all reduced in obstructed kidneys determined by qRT-PCR, which was unaffected by MnTBAP. Collectively, these results demonstrated an important role of mitochondrial oxidative stress in mediating the downregulation of sodium transporters in obstructive kidney disease.

Protective effect of hydrogen sulfide on renal injury in the experimental unilateral ureteral obstruction

Introduction/Objective:

Ureteral obstruction is a common pathology and causes kidney fibrosis and dysfunction at late period. In this present study, we investigated the antifibrotic and antiinflammatory effects of hydrogen sulfide on kidney damage after unilateral ureteral obstruction (UUO) in rats.

Materials and Methods:

24 rats were divided into four groups. Group 1 was control, group 2 was sham, group 3 included rats with UUO and group 4 rats with UUO which were given sodium hydrogen sulfide (NaHS)-exogenous donor of hydrogen sulfide (intraperitoneally 56μmoL/kg/day). After 14 days, rats were killed and their kidneys were taken and blood analysis was performed. Tubular necrosis, mononuclear cell infiltration and interstitial fibrosis were determined histopathologically in a part of the kidneys; nitric oxide (NO), malondialdehyde (MDA) and reduced glutathione (GSH) levels were determined in the other part of the kidneys. Urea-creatinine levels were investigated by blood analysis. Statistical analyses were made by the Chi-square test and one-way analysis of variance (ANOVA).

Results:

There was no significantly difference for urea-creatinine levels among groups. Pathologically, there was serious tubular necrosis and fibrosis in group 3 and there was significantly decreasing of tubular necrosis and fibrosis in group 4 (p<0.005). Also, there was significantly increase of NO and MDA levels and decrease of GSH levels in group 3 compared to other groups (p<0.005).

Conclusions:

hydrogen sulfide prevents kidney damage with antioxidant and antiinflammatory effect.

Disruption of cyclooxygenase type 2 exacerbates apoptosis and renal damage during obstructive nephropathy

Renal oxidative stress is increased in response to ureteral obstruction. In vitro, cyclooxygenase (COX)-2 activity contributes to protection against oxidants. In the present study, we tested the hypothesis that COX-2 activity counters oxidative stress and apoptosis in an in vivo model of obstructive nephropathy. Renal oxidative stress markers, antioxidant enzymes, and markers of tubular injury, tubular dilation, and apoptosis were investigated in COX-2 knockout (COX-2(-/-)) and wild-type (WT) mice subjected to 3 or 7 days of unilateral ureteral obstruction (UUO). In a separate series, WT sham-operated and UUO mice were treated with a selective COX-2 inhibitor, parecoxib. COX-2 increased in response to UUO; the oxidative stress markers 4-hydroxynonenal and nitrotyrosine protein residues increased in kidney tissue with no genotype difference after UUO, whereas the antioxidant enzymes heme oxygenase-1 and SOD2 displayed higher levels in COX-2(-/-) mice. Tubular injury was aggravated by COX-2 deletion, as measured by tubular dilatation, an increase in kidney injury molecule-1, cortical caspase-3 content, and apoptosis index. In conclusion, COX-2 is necessary to protect against tubular injury and apoptosis after UUO but not necessary to protect against oxidative stress. COX-2 is not likely to directly regulate antioxidant enzymes heme oxygenase-1 and SOD in the kidney.

Systematic review and meta-analysis of the effect of alcohol intake on the risk of urolithiasis including dose-response relationship

OBJECTIVE

We conducted a meta-analysis to quantitatively evaluate the correlation between alcohol consumption and the risk of urolithiasis by summarizing the results of published case-control and cohort studies and the potential dose-response association.

METHODS

A systematic literature search of articles up to February 2014 was conducted via PubMed, Web of Science, Cochrane Library, Scopus, EMBASE, the Chinese National Knowledge Infrastructure databases, and the references of the retrieved articles. Fixed- or random-effect models were used to summarize the estimates of odds ratio (OR) with 95% confidence interval (95% CI) for the highest versus the lowest consumption of alcohol. A dose-response meta-analysis was also conducted.

RESULTS

The pooled OR estimates indicated that alcohol consumption was associated with a decreased risk of urolithiasis (OR=0.683, 95% CI 0.577-0.808). In addition, the dose-response meta-analysis indicated that the rate of urolithiasis decreased by 10% for a 10 g/day increase in alcohol intake (OR=0.898, 95% CI 0.851-0.948). No evidence of publication bias was found by Begg's or Egger's test (p=0.130, p=0.130, respectively).

CONCLUSION

Our meta-analysis indicated that alcohol intake is associated with a decreased risk of urolithiasis.

Alpha-lipoic acid attenuates renal injury in rats with obstructive nephropathy

This study was established to determine the possible protective effects of alpha-lipoic acid (ALA), a powerful antioxidant, on renal injury in obstructive nephropathy. Male Sprague-Dawley rats were assigned into sham-operated unilateral ureteral obstruction (UUO) and UUO treated with ALA groups. ALA 60 mg/kg was injected intraperitoneally 2 days before UUO induction and continued afterward for 7 days. Renal function, oxidative stress markers, nitric oxide, transforming growth factor-1 (TGF-β1), and histological changes were evaluated at the end of the experiment. Obstruction of the ureter resulted in renal dysfunction as indicated by significant increases in blood urea nitrogen and serum creatinine. Nonobstructed contralateral kidneys in all groups examined did not show any morphological or biochemical alterations. In untreated UUO group, the obstructed kidney developed marked hydronephrosis, leukocyte infiltration, and severe interstitial fibrosis. These functional and structural changes were associated with significant increases in tissue levels of malondialdehyde, nitric oxide, and TGF-β1 but decreases in reduced glutathione and total antioxidant capacity. Pretreatment with ALA significantly minimized all the changes elicited by ureteral obstruction. These findings demonstrate that ALA supplementation attenuates renal injury in rats with obstructive nephropathy and further suggest that oxidative stress inhibition is likely to be involved in the beneficial effects of this compound.

Alleviation of kidney damage induced by unilateral ureter obstruction in rats by Rhodiola rosea

PURPOSE

To evaluate the efficacy of Rhodiola rosea extract in terms of alleviating the renal damage induced by unilateral ureter obstruction (UUO) in rats.

MATERIAL AND METHODS

Thirty Wistar albino male rats were divided into five groups: (I) Control, (II) UUO 7 days, (III) UUO 7 days+extract,(IV) UUO 14 days, and (V) UUO 14 days+extract. Seven or 14 days after the initiation of the experimental procedure, the left kidneys of rats in all five groups were removed for histological examination, and their blood was drawn for biochemical measurements.

RESULT

Median malondialdehyde (MDA) and glutathione peroxidase (GPx) levels were, respectively, 39.4 (5.04) nmol/mL and 25.8 (8.01) nmol/minute/mL in group I, 77.9 (12.38) nmol/mL and 5.8 (1.95) nmol/minute/mL in group II, 48.7 (12.1) nmol/mL and 9.1 (2.3) nmol/minute/mL in group III, 58.5 (23.83) nmol/mL and 8.4 (2.1) nmol/minute/mL in group IV, and 44.8 (4.97) nmol/mL and 13.8 (3.73) nmol/minute/mL in group V. There was a statistically significant difference among the groups in terms of MDA and GPx levels (p<0.05 for both). The median numbers of apoptotic cells were 1 (1), 8 (2.25), 3 (1.25), 23.5 (9), and 7 (I) in groups I, II, III, IV, and V, respectively. There was a statistically siginificant difference among the groups in terms of apoptotic cell number (p<0.05).

CONCLUSION

R. rosea extract was shown to alleviate the renal damage induced by UUO through its antioxidant effects. The mechanism by which R. rosea extract causes these effects merits further investigation.

Hydrogen-rich saline ameliorates renal injury induced by unilateral ureteral obstruction in rats

Hydrogen has been demonstrated to have effective protection against tissue injuries caused by oxidative stress, inflammation, and apoptosis. This study investigated the efficacy of hydrogen-rich saline (HS) on the prevention of renal injury induced by unilateral ureteric obstruction (UUO) in rats. Male Sprague-Dawley rats were divided randomly into 4 groups: sham group, UUO group, UUO+saline group, and UUO+HS group. UUO was induced by ligation of the left ureter. 5ml/kg HRSS or saline was administered beginning 1day after UUO and for 10days thereafter. Rats were killed at 10days after UUO. Left kidneys were excised immediately for the tissue histologic examinations and biochemical assays. Renal injury scores in the UUO group and the UUO+saline group were significantly higher compared with those in the sham group. However, administration of HS significantly reduced the injury score. Apoptosis index was significantly increased in UUO group and the UUO+saline group. HS treatment also reduced the apoptosis index. Interstitial fibrosis and macrophage infiltration were obvious in UUO kidneys. However, HS treatment significantly reduced the fibrosis and infiltration of macrophage in UUO kidneys. Significant increase in the MDA level and decrease in the SOD activity were observed in UUO group and the UUO+saline group. MDA level of UUO+HS group was significantly reduced. In addition, SOD activity of was significantly improved after treatment of HS. The data provide a biochemical and histologic basis for HS acting as a novel therapeutic strategy for preventing the renal injury induced by UUO.

Loss of glutathione S-transferase A4 accelerates obstruction-induced tubule damage and renal fibrosis

Glutathione transferase isozyme A4 (GSTA4) exhibits high catalytic efficiency to metabolize 4-hydroxynonenal (4-HNE), a highly reactive lipid peroxidation product that has been implicated in the pathogenesis of various chronic diseases. We investigated the role of 4-HNE in the mechanisms of unilateral ureteral obstruction (UUO)-induced fibrosis and its modulation by GSTA4-4 in a mouse model. Our data indicate that after UUO, accumulation of 4-HNE and its adducts were increased in renal tissues, with a concomitant decrease in the expression of GSTA4-4 in mice. As compared to wild-type (WT) mice, UUO caused an increased expression of fibroblast markers in the interstitium of GSTA4 KO mice. Additionally, increased autophagy and tubular cell damage were more severe in UUO-treated GSTA4 KO mice than in WT mice. Furthermore, GSK-3β phosphorylation and expression of Snail, a regulator of E-cadherin and Occludin, was found to be significantly higher in UUO-inflicted GSTA4 KO mice. GSTA4 over-expression prevented 4-HNE-induced autophagy activation, tubular cell damage and Snail nuclear translocation in vitro. The effects of long-term expression of GSTA4 in restoration of UUO-induced damage in mice with the GSTA4 inducible transposon system indicated that release of obstruction after 3 days of UUO resulted in the attenuation of interstitial SMAα and collagen I expression. This transposon-delivered GSTA4 expression also suppressed UUO-induced loss of tubular cell junction markers and autophagy activation. Together, these results indicate that 4-HNE significantly contributes to the mechanisms of tubule injury and fibrosis and that these effects can be inhibited by the enhanced expression of GSTA4-4.

Dietary factors and risk of kidney stone: a case-control study in southern China

OBJECTIVE

Formation of kidney stones is a multifactorial disease, and diet and lifestyle are suggested to contribute remarkably to increased prevalence. The population of Guangzhou, China has a high prevalence rate of kidney stones; however, its risk factors are still unknown. The aim of this study was to investigate the dietary risk factors for kidney stones in southern China.

DESIGN

A case-control study was carried out.

SETTING

This study was carried out at the Department of Health Management Center, Guangzhou Nanfang Hospital, China.

SUBJECTS

This study involved 1,019 newly diagnosed kidney stone patients and 987 healthy control subjects.

INTERVENTION

A questionnaire regarding dietary patterns and supplements was used to investigate the risk factors for kidney stone formation.

MAIN OUTCOME MEASURE

Food intake frequency, beverage and alcohol consumption, food supplements, and anthropometry were assessed.

RESULTS

In the analysis, we found positive associations of kidney stones with consumption of grains (odds ratio [OR] = 2.08; 95% confidence interval [CI] = 1.08, 4.02) and bean products (OR = 3.50; 95% CI = 1.61, 7.59) in women. The variable "fluid drinking" showed a significant protective effect against kidney stones in men (OR = 0.57; 95% CI = 0.36, 0.88). Consuming leafy vegetables more than 3 times per day was positively associated with stones in both men and women (OR = 2.02; 95% CI = 1.04, 3.91 and OR = 3.86; 95% CI = 1.48, 10.04, respectively). Other dietary factors, dietary supplements, and specific food were not related to kidney stone formation in Guangzhou, China.

CONCLUSION

The results confirmed that specific diet can affect stone formation in the Chinese population, and varied risk factors were found for different genders.

Induction of oxidative stress in kidney

Oxidative stress has a critical role in the pathophysiology of several kidney diseases, and many complications of these diseases are mediated by oxidative stress, oxidative stress-related mediators, and inflammation. Several systemic diseases such as hypertension, diabetes mellitus, and hypercholesterolemia; infection; antibiotics, chemotherapeutics, and radiocontrast agents; and environmental toxins, occupational chemicals, radiation, smoking, as well as alcohol consumption induce oxidative stress in kidney. We searched the literature using PubMed, MEDLINE, and Google scholar with “oxidative stress, reactive oxygen species, oxygen free radicals, kidney, renal injury, nephropathy, nephrotoxicity, and induction”. The literature search included only articles written in English language. Letters or case reports were excluded. Scientific relevance, for clinical studies target populations, and study design, for basic science studies full coverage of main topics, are eligibility criteria for articles used in this paper.

1,2,3,4,6-Penta-O-galloyl-beta-D-glucose reduces renal crystallization and oxidative stress in a hyperoxaluric rat model

Adhesion of calcium oxalate (CaOx) crystals to kidney cells may be a key event in the pathogenesis of kidney stones associated with marked hyperoxaluria. Previously, we found that 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), isolated from a traditional medicinal herb, reduced CaOx crystal adhesion to renal epithelial cells by acting on the cells as well as on the crystal surface. Here we used the ethylene glycol (EG)-mediated hyperoxaluric rat model and found evidence of oxidant stress as indicated by decreases in the activities of the renal antioxidant enzymes, superoxide dismutase, catalase, and glutathione peroxidase, with increased kidney cell apoptosis and serum malondialdehyde levels, all evident by 21 days of EG treatment. These effects of hyperoxaluria were reversed by concurrent PGG treatment along with decreased urinary oxalate levels and CaOx supersaturation. Renal epithelial cell expression of the crystal binding molecule hyaluronan increased diffusely within 7 days of EG initiation, suggesting it is not a result of but precedes crystal deposition. Renal cell osteopontin (OPN) was also upregulated in EG-treated animals, and PGG significantly attenuated overexpression of both OPN and hyaluronan. Thus, our findings demonstrate that PGG reduces renal crystallization and oxidative renal cell injury, and may be a candidate chemopreventive agent for nephrolithiasis.