Ureteropelvic junction obstruction causes histologic alterations in contralateral kidney

Investigation of reno-protective efficacy of thymoquinone in a unilateral hydronephrosis model

We aimed to evaluate the effects of the antioxidant thymoquinone on treated and untreated kidneys on histological and oxidative parameters as well as Kidney Injury Molecule (KIM-1) levels in an experimental unilateral ureteropelvic junction obstruction (UPJO) with resultant hydronephrosis (HN) model. In adherence to the Animal research: reporting of in vivo exepriments guidelines, 34 male Wistar rats were randomly divided into four groups which were named accordingly: "CO" (corn oil), "TQ" (thymoquinone and corn oil), "HNCO" (UPJO-HN and corn oil), "HNTQ" (UPJO-HN, thymoquinone and corn oil). Histologically, pelvic epithelial damage, glomerular shrinkage and sclerosis, tubular damage, interstitial edema-inflammation-fibrosis (IEIF), and vascular congestion were assessed. Biochemically, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione reductase (GR) and KIM-1 levels were assessed. Macroscopic HN developed in all obstructed kidneys. Ipsilateral obstructed kidneys deteriorated in all histological parameters. Thymoquinone attenuated glomerular shrinkage and sclerosis alterations but increased vascular congestion. Contralateral non-obstructed kidneys also showed histological deterioration. Thymoquinone had beneficial effects in terms of IEIF presence in contralateral kidneys but it increased vascular congestion. MDA and SOD results were inconclusive. UPJO caused decreased GR levels in the ipsilateral kidneys but not in the contralateral ones. This effect was not ameliorated by thymoquinone treatment. KIM-1 levels were increased in ipsilateral obstructed kidneys with a lower level in HNTQ group than in HNCO. KIM-1 level of the ipsilateral HNTQ group was higher than in both non-obstructed ipsilateral kidney groups. The effect of thymoquinone in ameliorating bilaterally observed histological alterations was limited and controversial. Oxidative damage detected by GR measurements was not prevented by thymoquinone. Thymoquinone partially decreased the damage as evidenced by reduced KIM-1 levels in thymoquinone-treated obstructed kidneys.

Huoxue Jiedu Huayu Formula Alleviates Cell Pyroptosis in Contralateral Kidneys of 6-Month-Old UUO Rats through the NLRP3/Caspase-1/IL-1β Pathway

Objectives

To study the protective effects and mechanisms of Huoxue Jiedu Huayu formula on cell pyroptosis through the NLRP3/caspase-1/IL-1β pathway in contralateral kidneys in 6-month-old unilateral ureteral obstruction (UUO) rats.

Methods

Wistar rats were randomly assigned to 5 groups: a Sham group, a unilateral nephrectomy group (UNX group), a UUO group, a UUO treated with spironolactone group (Spi group), and a UUO treated with Huoxue Jiedu Huayu formula group (HJHF group). After 6 months of oral drug intervention, blood and contralateral kidneys were collected for research.

Results

The morphology and function of the contralateral kidneys were essentially normal after unilateral nephrectomy. HJHF obviously decreased serum creatinine, urea, and inflammatory lesions and depressed cell pyroptosis based on the NLRP3/caspase-1/IL-1β pathway. Moreover, spironolactone, a mineralocorticoid receptor (MR) blocker, suppressed cell pyroptosis through SGK-1 and NF-кB.

Conclusion

HJHF and spirolactone inhibited excessive activation of MR and then reduced cell pyroptosis, which was dependent on the NLRP3/caspase-1/IL-1β pathway, to protect the contralateral kidneys of 6-month-old UUO rats.

Targeting Interstitial Myofibroblast-Expressed Integrin αvβ3 Alleviates Renal Fibrosis

Renal fibrosis is the final manifestation of various chronic kidney diseases. Interstitial myofibroblasts, which are reported to highly express integrin αvβ3, are the effector cells in renal fibrogenesis. Since current therapies do not efficiently target these cells, there is no effective therapeutic method for preventing or mitigating the disease. Here, we modified sterically stable PEGylated liposomes with the pentapeptide cRGDfC (RGD-Lip), which has a high affinity for αvβ3, to specifically deliver drug to renal interstitial myofibroblasts. Our results showed that attaching cRGDfC to liposomes significantly increased their uptake by activated renal fibroblasts NRK-49F cells, and this effect was greatly abolished by adding excess-free cRGDfC or a knockdown of αvβ3. Systemic administration of RGD-Lip gave rise to significant accumulation in a fibrotic kidney, which is ascribed to the specific recognition with integrin αvβ3 on interstitial myofibroblasts. When loaded with celastrol, RGD-guided liposomes dramatically depressed the proliferation and activation of NRK-49F cells in vitro. Additionally, celastrol-loaded RGD-Lip markedly attenuated renal fibrosis, injury, and inflammation induced by unilateral ureteral obstruction (UUO) in mice, without inducing significant systemic toxicity. Thus, this liposomal system shows great promise for delivering therapeutic agents to interstitial myofibroblasts for renal fibrosis treatment with minimal side effects.

The effect of coenzyme Q and selenium on kidney in rats with partial unilateral ureteral obstruction

OBJECTIVE

In this study, we aimed to investigate the antioxidant effects of selenium and coenzyme Q on renal damage in a partial unilateral ureteral obstruction (PUUO) in a rat model.

MATERIAL AND METHODS

A total of 24 Sprague-Dawley rats were divided into four groups as Group 1 Control Group, Group 2, PUUO Group, Group 3 PUUO + coenzyme Q group, Group 4 PUUO + selenium group. Paraoxonase (PON), total antioxidant capacity (TAC), and total oxidant levels (TOS) were analyzed biochemically from tissue and blood samples. Tissue samples were examined histopathologically.

RESULTS

The TAC in the tissues was found to be statistically significantly increased in Groups 3 and 4, compared to Group 2. Tissue TOS was found to be significantly reduced in Groups 3 and 4, compared to Group 2. Serum PON levels were significantly increased in Group 3 and 4, compared to Group 1 and 2. Histopathological examination showed that interstitial inflammation and congestion were lesser in the coenzyme Q and selenium groups than in the PUUO group. A more significant decrease was found in the selenium group than in the coenzyme Q group.

CONCLUSION

Our study results showed that coenzyme Q and selenium reduced the oxidation and the damage in tissue in PUUO in rats.

Nitric oxide and asymmetric dimethyl arginine (ADMA) levels in an experimental hydronephrotic kidney caused by unilateral partial ureteral obstruction

Aim

Our aim is to measure asymmetric dimethyl arginine and nitric oxide levels in rats with induced unilateral acute ureteral obstruction to research the effects on the kidney.

Material and Methods

The study included 21 adolescent (average age 6 weeks) Sprague-Dawley male rats weighing between 240-290g divided at random into 3 groups. Group-1: Control group (n=6): underwent no procedures. Group-2: Sham group (n=6): underwent the same procedures as the experimental group without ureter and psoas muscle dissection. Group-3: Group with induced partial unilateral ureteral obstruction (n=9). All rats were sacrificed after 12 weeks. Superoxide dismutase enzyme activity and nitrite and nitrate salt levels were measured in renal tissue. Plasma nitrite-nitrate and ADMA levels were examined.

Results

In the experimental group histopathological changes observed included renal pelvis dilatation, flattened papillae, sclerotic glomerulus and fibrosis. In the experimental group tissue SOD and blood ADMA levels were higher than the control and sham groups (p<0.05) while tissue NO and plasma NO values were lower than in the sham and control groups (p<0.05).

Conclusion

Oxidative stress and disruption of NO synthesis play an important role in renal function and histopathological changes after obstructive renal disease. To prevent renal complications developing after obstructive nephropathy we believe that a new strategy may be research on reducing ADMA.

GYY4137, a Slow-Releasing Hydrogen Sulfide Donor, Ameliorates Renal Damage Associated with Chronic Obstructive Uropathy

PURPOSE

Chronic obstructive uropathy can cause irreversible kidney injury, atrophy and inflammation, which can ultimately lead to fibrosis. Epithelial-mesenchymal transition is a key trigger of fibrosis that is caused by up-regulation of TGF-β1 (transforming growth factor-β1) and ANGII (angiotensin II). H₂S is an endogenously produced gasotransmitter with cytoprotective properties. We sought to elucidate the effects of the slow-releasing H₂S donor GYY4137 on chronic ureteral obstruction and evaluate the potential mechanisms.

MATERIALS AND METHODS

Following unilateral ureteral obstruction male Lewis rats were given daily intraperitoneal administration of phosphate buffered saline vehicle (obstruction group) or phosphate buffered saline plus 200 μmol/kg GYY4137 (obstruction plus GYY4137 group) for 30 days. Urine and serum samples were collected to determine physiological parameters of renal function and injury. Kidneys were removed on postoperative day 30 to evaluate histopathology and protein expression. Epithelial-mesenchymal transition in LLC-PK1 pig kidney epithelial cells was induced with TGF-β1 and treated with GYY4137 to evaluate potential mechanisms via in vitro scratch wound assays.

RESULTS

H₂S treatment decreased serum creatinine and the urine protein-to-creatinine excretion ratio after unilateral ureteral obstruction. In addition, H₂S mitigated cortical loss, inflammatory damage and tubulointerstitial fibrosis. Tissues showed decreased expression of epithelial-mesenchymal transition markers upon H₂S treatment. Epithelial-mesenchymal transition progression in LLC-PK1 was alleviated upon in vitro administration of GYY4137.

CONCLUSIONS

To our knowledge our findings demonstrate for the first time the protective effects of H₂S in chronic obstructive uropathy. This may represent a potential therapeutic solution to ameliorate renal damage and improve the clinical outcomes of urinary obstruction.

Diffusion tensor imaging and tractography of the kidney in children: feasibility and preliminary experience

BACKGROUND

Functional magnetic resonance urography (fMRU) provides morphological and functional information based on perfusion. Diffusion tensor imaging (DTI) complements fMRU by measuring renal microstructure and provides insight into the relationship between renal structure and function.

OBJECTIVE

To evaluate the feasibility and utility of renal DTI and tractography in the setting of fMRU in children.

MATERIALS AND METHODS

We prospectively enrolled 9 children (6 boys, 3 girls) with a mean age of 4.3 years (range 6 months to 14.8 years). All children were examined with MRI at 3.0 tesla. DTI was acquired with an echo-planar sequence (TR/TE = 2,300/69 ms, b = 300 s/mm2) with 12 non-collinear directions and 3 signal averages. Functional MRU results were used to group the moieties as normal or abnormal. Regions of interest were placed in the medulla and cortex to measure DTI parameters of microstructure. DTI tractography measures of parenchymal volume were compared to fMRU-derived volumes.

RESULTS

We analyzed 19 moieties (13 normal; 6 abnormal). Tractography of normal moieties showed numerous tracks with a radial arrangement and convergence into pyramids. Abnormal moieties did not show the radial arrangement or converging architecture and had tracks that were loosely arranged and left hollow spaces. Tractography volume correlated with MRU parenchymal volume (r 2 = 0.93, P < 0.005) and abnormal moieties exhibited greater tractography volume than normal moieties (P < 0.005). Tractography volume also correlated with age of the child (P < 0.001). In normal moieties, the medulla had higher fractional anisotropy (0.401 +/−0.05) than the cortex (0.183 +/− 0.03) (P < 0.001); fractional anisotropy in these regions did not change with age (P > 0.1). There were no differences in apparent diffusion coefficient values between the cortex and medulla (P > 0.5). We observed a trend of increasing apparent diffusion coefficient values with age in the cortex and medulla, which did not reach statistical significance (cortex: r2 = 0.21, P > 0.1; medulla: r2 = 0.135, P > 0.1).

CONCLUSION

DTI with tractography is feasible in children and can complement the functional information obtained from fMRU.

Histologic differences between extrinsic and intrinsic ureteropelvic junction obstruction

OBJECTIVE

Ureteropelvic junction obstruction (UPJ) can be caused by intrinsic disorganization or extrinsic compression from crossing vessels (CV). What is not clear is whether there is also intrinsic UPJ pathology in patients with CV. Recent surgeries, such as the Hellström vascular hitch procedure, move the CV cephalad without resecting the UPJ, which presumes no intrinsic narrowing. Our aim was to determine whether the histologic features of the 2 types of UPJ obstruction are distinct enough to enable a blinded pathologist to histologically identify the cause of obstruction.

METHODS

We reviewed all patients undergoing pyeloplasties from 2000 to 2006. All CV cases with available pathology were selected. A random selection of intrinsic cases was used as controls. One blinded pathologist reviewed the histology, specifically scoring muscle and collagen density.

RESULTS

Sixteen patients were reviewed. Seven had CV and 9 had intrinsic obstruction. Muscle density was different between the 2 groups with CV denser compared with intrinsic (P = .005). The pathologist correctly assigned the cause of obstruction in 5/7 (71%) of CV and 7/9 (78%) of intrinsic cases (P = .039).

CONCLUSIONS

Identification of a significant CV intraoperatively does translate to a discernible appearance histologically.