Glomerular Tuft Research Articles

Evaluation of podocytopathy in patients with no abnormality detected by light microscopy

ABSTRACT When podocytes are injured, they may detach leading to podocytopenia, which represents a critical step in the development of podocytopathy. . This study aimed to study the diagnostic role of colloidal iron stain in assessment of podoctyopathy. This is a retrospective study, conducted on 50 archival renal biopsies with the clinical diagnosis of steroid resistant or dependent nephrotic syndrome and with no abnormality detected by light microscopy (LM). Colloidal iron special stain was used to delineate the sialomucin coat of podocytes. Desmin immunohistochemical stain for assessment of podocyte injury was also applied. Electron microscopic (EM) examination was performed. Assessment of the mean percent of colloidal iron and desmin stained pixels in relation to the surface glomerular tuft area; i.e. mean percent of stained area (PSA) was done using image analysis software. Minimal change disease (MCD) was observed in 38/50 (76%) cases. Podocytopathy with detached podocytes was observed in 12/50 (24%) cases. Mean PSA in cases diagnosed as MCD was 19.17 ± 2.42 and was 18.95 ± 3.18 in cases diagnosed as podocytopathy with detached podocytes, while in control cases, mean PSA was 23.61 ± 2.18 which showed statistically significant difference between (p value = ≤0.001). Colloidal iron stain is an easy routine-friendly method for assessment of podocytopathy.

Improvement in Kidney damage resulting from stanozolol intramuscular injections in rats by Natural Cocoa Powder (NCP) Administration.

BackgroundStanozolol, an anabolic steroid, has been shown to induce kidney damage through mechanisms involving oxidative stress and inflammation. Natural Cocoa Powder (NCP), known for its high antioxidant content, may offer protective effects against such damage. AimThis study aimed to evaluate the potential of Natural Cocoa Powder (NCP) in ameliorating kidney damage caused by stanozolol intramuscular injections in rats. MethodsThirty rats were randomly assigned into five groups (G1–G5) and fed with standard rat chow. G1 and G3 received 2 mg/kg stanozolol intramuscularly twice weekly, G2 and G4 received 5 mg/kg stanozolol twice weekly, while G5 served as the control with no stanozolol. G1, G2, and G5 had 24-hour access to water, while G3 and G4 had water replaced with 2% NCP from 6 am to 6 pm daily. After 8 weeks, kidneys were perfusion-fixed and analyzed histomorphometrically for proximal/distal tubules, Bowman's space, glomerular tuft, and renal corpuscle composition.Before and after treatments, renal function was measured by serum creatinine and blood urea nitrogen, whilst systemic inflammation was monitored by erythrocyte sedimentation rate and serum C-reactive protein tests. Results & DiscussionStanozolol administration significantly increased kidney damage in a dose-dependent manner, with marked rises in the volume densities of the proximal convoluted tubule (PCT), distal convoluted tubule (DCT), glomerular tuft, and renal corpuscle. At higher doses, PCT and DCT volume densities increased by 143% and 223%, respectively, compared to controls. Natural cocoa powder (NCP) mitigated these effects, reducing PCT, DCT, and glomerular tuft volume densities by 92%, 77%, and 86%, respectively. Stanozolol also elevated serum markers of kidney dysfunction and inflammation, such as blood urea nitrogen (BUN), serum creatinine (SCr), and C-reactive protein (CRP). While NCP significantly lowered BUN and SCr levels, it did not fully normalize CRP, which remained elevated in stanozolol-treated rats. ConclusionIncreased volume density of kidney components indicated hypertrophy, which was associated with elevated serum creatinine, blood urea nitrogen (BUN), and C-reactive protein (CRP) levels, reflecting impaired renal function and heightened systemic inflammation. The reduction in these markers with NCP ingestion suggests its potential to mitigate stanozolol-induced renal damage. It is proposed that the antioxidant properties of NCP may have reduced inflammation by counteracting oxidative stress, thereby contributing to the observed improvement in kidney function and structure.

Effect of Arabic Gum on Gentamicin Nephrotoxicity in Mice: A Pathological Study

<p><strong>Aim</strong> To investigate the effect of Arabic gum on gentamycin nephrotoxicity in mice kidney.<br /><strong>Methods</strong> Forty (40) mice were divided into five groups, eight mice in each. Group one (G1) stands for the negative control group. The second one (G2) was injected with gentamycin only, while the third one (G3) was given an Arabic gum orally 10g/kg. The 4th group (G4) was injected with gentamycin for 8 days, and then followed by Arabic gum orally for 8 days. The fifth group (G5) was injected with gentamycin plus oral administration of Arabic gum at the same time. A scoring system (+1-+4) was used to grade the histological features in the kidneys.<br /><strong>Results</strong> The results revealed a significant increase in body weight in G3 group only; this group presented a significant decrease in the level of both urea and creatinine. Group G2 showed a marked elevation in both serum urea and creatinine. Acute tubular necrosis (+4), in both G2 and G5. In G3, kidney sections presented mild cell swelling of the tubular epithelium in addition to the normal architectures (score +1), while G4 sections revealed tubular hyalin cast, expansion of glomerular tufts.<br /><strong>Conclusion</strong> The research indicates that gentamycin leads to kidney damage in mice. Arabic gum could be a treatment option although additional studies are required to determine the best dosing and timing, for optimal effectiveness.</p>

Mitochondrial-Derived Signaling Mediates Differentiation of Parietal Epithelial Cells into Podocytes.

Aims: Parietal epithelial cells (PECs) are potential stem cells within the glomerulus, migrating into site of podocyte loss to differentiate into podocytes. Little is known about the mechanism mediating differentiation of PECs into podocytes. Results: In vitro differentiation of PECs into podocytes led to upregulation of podocyte markers such as Wilms' tumor gene 1 (WT-1), Forkhead box C1 (FOXC1), synaptopodin and podocin, accompanied by increased mitochondrial abundance. Preincubation with a mitochondrial reactive oxygen species (ROS) inhibitor prevented all these events in PECs. In vivo, adriamycin (ADR)-treated mice exhibited albuminuria, decreased WT1 positive cells, and claudin-1 expressed in glomerular capillary tuft, as well as peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) overproduction in PECs. Expression of the ROS-related molecule nuclear factor erythroid 2-related factor 2 (Nrf2) and its target protein Brahma-related gene 1 (Brg1) increased during differentiation of PECs into podocytes. Suppressing Nrf2 or Brg1 reduced the differentiation of PECs, whereas overexpression had the opposite effect. Brg1 directly regulated WT-1 transcription in PECs. Activation of Nrf2 with bardoxolone-methyl (CDDO-Me) resulted in less proteinuria and more WT1 positive cells in ADR mice. PECs conditional human Nrf2 knock-in mice showed increased WT1 cell numbers. Conclusion: It concluded that mitochondria-derived ROS mediated differentiation of PECs into podocytes via Nrf2 and Brg1 signaling.

Ameliorating Effect of Grape (Vitis vinifera L.) Seed and Peel Extracts with Selenium on Ochratoxin-A Exposed Renal Dysfunction in Male Wistar Rats

Background and AimDrug-induced nephrotoxicity is extensively documented as the initial stage of kidney disease that particularly results in acute renal injury and chronic renal dysfunction. The single and combined effect of grape peel extract (GPE), grape seed extracts (GSE) and selenium (Sel) were investigated in current study for controlling of renal injury induced by Ochratoxin-A (OTA) in male rats. MethodsForty nine male Wistar rats weighing 200 ± 10 g were injected with OTA (0.5 mg/kg bw) to induce nephrotoxicity, then treated with singleand combined applications of GSE, GPE and Sel. In addition, the OTA induced nephrotoxicity rats were screened for various biological and physiological parameters like food ingestion, body weight gain, liver weight, serum kidney biomarkers, serum lipid fractions, enzymatic and non-enzymatic lipid peroxidation indicators and histopathological studies. ResultsOur findings suggested that the combination of GSE 2 % and Sel (50–50) treatment reduced renal dysfunction in OTA-induced rats by significantly lowering lipid peroxidation indicators, lipid and kidneys profiles and enhancing enzymatic and non-enzymatic antioxidants biomarkers followed by GSE 2 % then Selenium (0.4 mg/kg) in OTA. Histological analysis of the kidney revealed more severe renal tubule degeneration in OTA-induced rats, While GSE and GPE combonation showed only moderate glomerular tuft enlargement and minimal renal tubule deterioration. Furthermore, the combination of GSE 2 %+Sel (50–50) revealed normal histological structure. ConclusionsGrape seed extracts along with selenium mightbe used as dietary supplements to reduce renal toxicity induced by chemicals or compounds that cause nephrotoxicity.

Pomegranate juice recuperates N’-Nitrosodiethylamine-induced kidney injury: evidence from biochemical and histological approaches

BackgroundPomegranate is considered as one of the oldest elixirs having various properties. Renal fibrosis is a preliminary sign of pathological degradation in most ailments related to kidney. Several efforts have been made for the discovery of cost-effective and safe therapeutics for the alleviation of renal diseases. There is a major dearth of studies on the action of pomegranate juice (PGJ) against NDEA-instigated kidney injury. This study investigates the protective and antifibrotic action of PGJ in restricting the occurrence of experimental renal fibrosis in Wistar rats. Renal injury was generated by a single intraperitoneal dose of 10 ml kg−1 b.wt. (1% NDEA stock), while fresh PGJ (i.p.) in doses of 2 ml kg−1 b.wt was administered thrice a week on alternate days for two weeks to observe amelioration. The renal function indices (blood urea, creatinine, and uric acid), SOD, CAT, LPO levels and renal anatomy (H&E, MT, Picrosirius and SEM) were investigated.ResultsThe assessment of renal function demonstrates augmented levels of blood urea, creatinine and uric acid in NDEA-administered groups in comparison with controls. SOD, CAT declined significantly in NDEA Day-7- and Day-14-treated animals, while the MDA levels raised by ~ 70.5% and ~ 76.3% in these groups, respectively. However, supplementation of PGJ provided recuperation from these elevated levels in injured groups. H&E staining of the controls exhibited normal renal structure with intact glomerulus and Bowman’s capsule, while NDEA generated congestion of glomerular tuft, convoluted tubules with cloudy swelling and multiple subsidence of the renal tissue. Noticeable presence of collagen fibers in the interstitium of cortex region of kidney was observed by MT staining along with gross ultrastructural deterioration in NDEA-administered animals by electron microscopy. PGJ supplementation exhibited restoration of renal anatomy and physiology.ConclusionsPomegranate may be considered as a potent nutraceutical to prevent NDEA-induced renal damage and may be included as a daily dietary supplement.

A translational model of chronic diabetic nephropathy in the Nile grass rat.

Diabetic nephropathy (DN) is a major healthcare challenge for individuals with diabetes and associated with increased cardiovascular morbidity and mortality. The existing rodent models do not fully represent the complex course of the human disease. Hence, developing a translational model of diabetes that reproduces both the early and the advanced characteristics of DN and faithfully recapitulates the overall human pathology is an unmet need. Here, we introduce the Nile grass rat (NGR) as a novel model of DN and characterize key pathologies underlying DN. NGRs spontaneously developed insulin resistance, reactive hyperinsulinemia, and hyperglycemia. Diabetic NGRs evolved DN and the key histopathological aspects of the human advanced DN, including glomerular hypertrophy, infiltration of mononuclear cells, tubular dilatation, and atrophy. Enlargement of the glomerular tufts and the Bowman's capsule areas accompanied the expansion of the Bowman's space. Glomerular sclerosis, renal arteriolar hyalinosis, Kimmelsteil-Wilson nodular lesions, and protein cast formations in the kidneys of diabetic NGR occurred with DN. Diabetic kidneys displayed interstitial and glomerular fibrosis, key characteristics of late human pathology as well as thickening of the glomerular basement membrane and podocyte effacement. Signs of injury included glomerular lipid accumulation, significantly more apoptotic cells, and expression of KIM-1. Diabetic NGRs became hypertensive, a known risk factor for kidney dysfunction, and showed decreased glomerular filtration rate. Diabetic NGRs recapitulate the breadth of human DN pathology and reproduce the consequences of chronic kidney disease, including injury and loss of function of the kidney. Hence, NGR represents a robust model for studying DN-related complications and provides a new foundation for more detailed mechanistic studies of the genesis of nephropathy, and the development of new therapeutic approaches.

Mesangial Expansion by Morphometry at 5 y After Kidney Transplantation: Incidence, Risk Factors, and Association With Graft Loss.

Mesangial expansion (ME) is an understudied histologic lesion in renal allografts. The current Banff mm score is not reproducible and may miss important ME features. The study aimed to improve the quantification of ME using morphometry, assess changes over time, and determine its association with allograft loss. We studied ME in 1-y and 5-y surveillance biopsies in 835 kidney transplants performed between January 2000 and December 2013. ME was assessed using the Banff mm score by a central pathologist and by morphometry. We derived 3 different morphometric measures: (1) %ME mm (%glomeruli with ME in ≥2 lobules, like Banff mm); (2) %MEany (%glomeruli with any ME lesion); and (3) %ME area (sum of all ME areas/all glomerular tuft areas). Unadjusted and adjusted Cox models assessed the risk of death-censored allograft loss. From 1- to 5-y biopsies, the mean Banff mm score increased from 0.18 to 0.34, whereas %ME mm increased from 2.5% to 13.3%. Banff mm score had modest correlations with morphometric ME measures. Moderate-severe %ME mm was present in 20.1% of 5-y biopsies, whereas only 6.6% of Banff mm scores were. In general, higher ME on both 1- and 5-y biopsies was associated with a deceased donor, older recipient age, recipient diabetes/obesity (present in >50% of severely affected biopsies), higher hemoglobin A1c at 5 y posttransplant, and recurrent kidney disease. Higher ME on 5-y biopsies was associated with delayed graft function. A higher Banff mm score at 1-y biopsy and morphometry ME measures at 5-y biopsy were associated with rejection during the first year posttransplant. Morphometric ME measures were associated with allograft loss independent of Banff scores and all clinical characteristics, including kidney function and recurrent disease. The model with %MEany had the highest c-statistic (0.872). Banff mm score underestimates the pervasiveness of ME in 5-y biopsies. ME is common and associated with alloimmune and nonalloimmune causes of graft loss.

PAR1-mediated Non-periodical Synchronized Calcium Oscillations in Human Mesangial Cells.

Mesangial cells offer structural support to the glomerular tuft and regulate glomerular capillary flow through their contractile capabilities. These cells undergo phenotypic changes, such as proliferation and mesangial expansion, resulting in abnormal glomerular tuft formation and reduced capillary loops. Such adaptation to the changing environment is commonly associated with various glomerular diseases, including diabetic nephropathy and glomerulonephritis. Thrombin-induced mesangial remodeling was found in diabetic patients, and expression of the corresponding protease-activated receptors (PARs) in the renal mesangium was reported. However, the functional PAR-mediated signaling in mesangial cells was not examined. This study investigated protease-activated mechanisms regulating mesangial cell calcium waves that may play an essential role in the mesangial proliferation or constriction of the arteriolar cells. Our results indicate that coagulation proteases such as thrombin induce synchronized oscillations in cytoplasmic Ca2+ concentration of mesangial cells. The oscillations required PAR1 G-protein coupled receptors-related activation, but not a PAR4, and were further mediated presumably through store-operated calcium entry and transient receptor potential canonical 3 (TRPC3) channel activity. Understanding thrombin signaling pathways and their relation to mesangial cells, contractile or synthetic (proliferative) phenotype may play a role in the development of chronic kidney disease and requires further investigation.

#2305 Mice with a PAX2 missense variant are susceptible to experimental focal segmental glomerulosclerosis (FSGS) and display impaired glomerular repair

Abstract Background and Aims Focal segmental glomerulosclerosis (FSGS) is a histopathologic lesion observed in chronic kidney disease characterized by scarring of the glomerulus due to the injury and irreversible loss of highly specialized glomerular epithelial cells called podocytes. Recent studies suggest that podocytes may be regenerated by another population of glomerular epithelial cells called parietal epithelial cells (PECs), although this remains controversial. PAX2 is a transcription factor protein that regulates glomerular development and its expression persists in adult parietal epithelial cells (PECs), postulated to serve as a reservoir for podocytes in the event of injury and loss. Our team previously found that PAX2 pathogenic missense variants account for 4% of adult FSGS. In our present study, our aim is to determine whether PEC-mediated podocyte regeneration is impaired in mice with a pathogenic Pax2 missense variant (Pax2-MV). Method FSGS was induced in wildtype and Pax2-MV mice using Adriamycin. Urine samples were collected from mice every week for 28 days to measure proteinuria. At 28 days after Adriamycin injury, kidneys were collected for histopathology, transmission electron microscopy, and immunofluorescence staining for PAX2 and podocyte marker WT-1. Glomeruli from Adriamycin-injured mice were also isolated through intra-cardiac perfusion with Dynabeads and subjected to mass-spectrometry for proteomics analysis. Proteins with statistically-significant fold changes in expression levels were further analyzed by Gene Ontology to determine biological and molecular processes involved in pathogenesis. Kidney tissue from an FSGS patient with a pathogenic PAX2 missense variant was also examined by histopathology and PAX2 immunohistochemistry. Results Compared to wildtype, Pax2-MV mice were more susceptible to worsened FSGS after Adriamycin, as demonstrated by worsened glomerular scarring, increased podocyte injury and loss, and increased proteinuria, associated with increased morality in Pax2-MV mice (Fig. 1A-B). Wildtype mice showed fewer PAX2-expressing PECs after injury, accompanied by the occurrence of PAX2/WT-1 co-expressing glomerular tuft cells (Fig. 2A-B). These suggest that in Adriamycin-injured wildtype, PAX2-expressing PECs move to the glomerular tuft, where they trans-differentiate to a podocyte fate. In contrast, Pax2-MV mice showed no changes in numbers of PAX2-expressing PECs after injury, associated with fewer PAX2/WT-1 co-expressing glomerular tuft cells compared to injured wildtype (Fig. 2A-B). These suggest that in Adriamycin-injured Pax2-MV mice, PAX2-expressing PECs are unable to move to the glomerular tuft, resulting in decreased numbers of cells undergoing podocyte trans-differentiation. A subset of ectopic PAX2-expressing glomerular tuft cells after injury was increased in Pax2-MV mice (Fig. 2A), suggesting a pathologic process given the worse outcomes observed in these mice. Consistent with findings from injured Pax2-MV mice, we found that in an FSGS patient with a pathogenic PAX2 missense variant, PAX2-expressing glomerular tuft cells overlap with areas of glomerular scarring, while in a normal human kidney biopsy, PAX2 expression is only observed in PECs but not within glomerular tuft cells (Fig. 2A). Lastly, proteomics Gene Ontology analysis of isolated glomeruli demonstrated biological and molecular processes indicative of maladaptive glomerular repair in injured Pax2-MV mice, including decreased regulation of cell shape, decreased cell-cell junction assembly and decreased actin and cadherin binding compared to wildtype (Fig. 2C). Conclusion Altogether, our findings suggest that PAX2-expressing PECs migrate to the glomerular tuft to assist in podocyte regeneration in wildtype. However, this mechanism is impaired in Pax2-MV mice, leading to worsened podocyte loss and injury and further exacerbation of glomerular disease (Fig. 2C). Our findings provide a further understanding of normal and impaired regeneration mechanisms in FSGS, and our identified pathogenic mechanisms can be further harnessed for future therapeutic development.

#211 Low albumin levels are associated with intrarenal complement C4d deposits in critically ill patients with ANCA-associated renal vasculitides

Abstract Background and Aims Despite serum albumin levels being predictive for clinical outcome in ANCA-associated renal vasculitis, implications providing a direct link between low serum albumin levels and intrarenal lesions remain elusive. Therefore, we here aimed to systematically assess the clinical relevance of low albumin levels and scrutinize clinicopathological correlations to expand our current knowledge. Method We here retrospectively enrolled biopsy-proven cases of ANCA-associated renal vasculitis between 2015 till 2020 in a single-center observational study. Survival-curve analyses on long-term renal survival and short-term clinical recovery were performed. Correlative analyses between serum albumin levels, laboratory parameters, proteinuria levels, and histopathological lesions including tubulointerstitial immune cell infiltrates, lesions analogous to the Banff score and intrarenal complement deposition of C3c and C4d were performed. Results We here show that hypoalbuminemia below the median of 2.4 g/dL impairs long-term renal survival especially in MPO-positive ANCA-associated renal vasculitis (p = 0.006, HR: 5.0, 95% CI: 1.2-21.5), while short-term clinical recovery particularly in critically ill patients is negatively affected by low serum albumin levels (p = 0.0082, HR: 3.6, 95% CI: 1.1-11.7). Low albumin levels are associated with the urinary marker of tubular damage in the total cohort (β = −0.5, p = 0.01), PR3-ANCA (β = −0.5, p = 0.04) and MPO-ANCA (p = 0.002, β = −0.8), but not in critically ill patients (β = −0.5, p = 0.07) implying hypoalbuminemia to occur by extrarenal causation in the state of critical illness. We identified plasmacytic infiltrates to correlate with low albumin levels in the total cohort (β = −0.6, p = 0.004) and in the subgroup of critically ill patients (β = −0.7, p = 0.005). Banff-scored interstitial inflammation (i) was further observed to inversely correlate with albumin levels (β = −0.7, p = 0.02). Intrarenal C4d deposition showed a significant correlation with low serum albumin levels in the glomerular tuft (β = −0.4, p = 0.04) and in interstitial arteries (β = −0.7, p = 0.01). Conclusion In conclusion, long-term renal outcome is significantly affected by low serum albumin levels especially in the setting of MPO-ANCA seropositivity. By contrast, short-term recovery was predicted by low albumin levels in critically ill patients with ANCA-associated renal vasculitis. We here provide evidence that low levels of serum albumin might directly affect tubulointerstitial inflammation as reflected by plasmacytic immune-cell infiltration, and intrarenal C4d complement deposition in ANCA-associated renal vasculitis.

#1918 L-NAME accelerates the progression of diabetic kidney disease in mice

Abstract Background and Aims Diabetic kidney disease (DKD) represents one of the major causes of end stage kidney disease worldwide. Despite DN having such a high incidence, mouse models of DN rarely mimic all aspects of the human disease, besides showing very slow progression and sometimes maintenance issues. For this reason, in this project we aimed to develop an accelerated, reproducible and accessible mouse model of DN. Method For our experiments we chose 9-week-old female and male of the leptin receptor knock-out (BKS.Cg-Dock7m +/+ Leprdb/J) mice as type 2 diabetes model. As these mice are still not prone to develop severe kidney injury despite their diabetic condition, we administered the eNOS inhibitor L-NAME for 6 weeks, in order to suppress nitric oxide production and therefore to aggravate kidney damage. Mice were divided in three groups: one vehicle control group, one receiving 40/mg/kg/day of L-NAME and one receiving 80/mg/kg/day of L-NAME dissolved in drinking water. Blood pressure and glomerular filtration rate (GFR) were measured at different time points, together with glycemia and albuminuria. Weight and water intake were also monitored throughout the study. At the end of the experiment, animals were killed and blood and organs collected for further analysis. Results Mice treated with 80 mg/kg/day of L-NAME showed an average increase of 10 mmHg in systolic blood pressure, with a peak of 30 mmHg increase at week 4 of treatment. On the other hand, 40 mg/kg/day of L-NAME did show any effect on blood pressure. Despite the different effect on blood pressure, three weeks of L-NAME administration caused a significant reduction in GFR at both doses, with 5% reduction for the 40 mg-group and 23% for the 80 mg-group. For the 80 mg-group we observed an even further GFR decline after 5 weeks of treatment, with a 28% reduction. No change in GFR was observed in the controls. This decrease in GFR was accompanied by a 10-fold increase in urinary albumin for both experimental groups already after 3 weeks of treatment, which after 4 weeks slightly declined but remained significantly higher than the controls (p < 0.0001). At a histological level, PAS staining of kidney sections revealed that in particular mice treated with 80 mg of L-NAME have enlarged Bowman capsule and glomerular tuft area, besides a reduced glomerular capillary density, coinciding with mesangial expansion. We also stained for overall collagen deposition with picrosirius red staining in order to detect possible fibrosis formation. We then observed that 80 mg of L-NAME accelerates interstitial fibrosis in the cortical area of the kidney, which also overlapped with an increased deposition of collagen I. This increase in collage I was also detected in kidney cortex of mice treated with 40 mg of L-NAME, although their overall collagen deposition and therefore fibrotic tissue did not differ from the control group. The medullar region of kidneys was also analyzed, but none of the two experimental groups revealed significant differences in terms overall collagen or collagen I deposition. Unlike mesangial expansion and fibrosis, L-NAME did not influence microphages infiltration, as revealed by CD68 staining in kidney sections. This suggests that L-NAME treatment does not accelerate kidney damage by triggering or accelerating inflammatory processes. This was also confirmed by qPCR analysis of kidney tissue, where the expression pro-inflammatory markers, such as IL1β, TNFα and MCP-1, did not change in the experimental groups. Conclusion Our results show that L-NAME considerably accelerates the progression of DKD in diabetic mice, with GFR declining and progressive albuminuria already after 3 weeks. Such disfunction is confirmed at 6 weeks by histological analysis, where mesangial expansion and fibrosis were detected. This model can be used to assess the therapeutic potential of novel interventions aimed to slow down DKD.

Renin-Angiotensin System Signaling in Parietal Epithelial Cells

INTRODUCTION. Bowman's capsule surrounds the kidney glomerular tuft and consists of a monolayer of parietal epithelial cells (PECs) creating a physiologically functioning barrier between the urinary space and the renal interstitium. Pathophysiological PEC activation describes the phenotypic switch from their normal quiescent state to one of proliferation and migration to the glomerular tuft, leading to glomerular injury. The development of several proteinuric kidney diseases is closely associated with PEC activation, however, the mechanisms of functional receptor signaling in these cells are not well described. This study investigates the functional presence of renin-angiotensin system (RAS) components and corresponding intracellular mechanisms in PECs. Methods. The vibrodissociation method was utilized to obtain freshly isolated Bowman’s capsules from discarded adult male human transplant tissues and 12-week old Wistar male and female rats. Confocal fluorescent microscopy of freshly isolated Bowman’s capsule PECs was performed using Fluo-8 or DAF-FM fluorescent dyes to detect changes in intracellular Ca2+ concentrations and nitric oxide (NO) response to the variety of RAS peptides. RESULTS. In separate experiments on freshly isolated rodent and human Bowman’s capsule PECs, we demonstrate the changes in redox response to the stimulation of RAS components. In particular, the acute application of Ang II peptide caused a rapid increase in NO production. Interestingly, we did not indicate significant changes in intracellular Ca2+ influx. To find out which receptor is responsible for the NO release we preincubated PECs with AT1R and AT2R blockers (Losartan and PD123319 respectively). Our data indicate that RAS mediates NO production through the AT2R activation. There is no sex difference was observed in these experiments. Further experiments with the variety of nitric oxide synthase (NOS) pharmacology reveal the functional distribution of NOS in rodent PECs. CONCLUSION. Our study provides an overview of the RAS signaling within PECs. For the first time, we present evidence demonstrating a direct connection between Ang II and redox homeostasis in PECs. Further investigation using the developed approach will be essential for understanding the role of Bowman's capsule cells in the glomerulus and the development of potential treatment against the hyperplasia of activated PECs and corresponding chronic kidney pathologies. Funding Sources: R01 DK129227, R01 DK126720, VA CDA-2 1IK2BX005605-01. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

FINERENONE TREATMENT PREVENTS GLOMERULAR DAMAGE AND RENAL INTERSTITIAL INFLAMMATION IN TYPE 1 DIABETIC RATS WITH CHRONIC KIDNEY DISEASE

Objective: Finerenone (FIN), a non-steroidal mineralocorticoid receptor antagonist, has shown a protective effect on kidney and cardiovascular damage progression in type 1 diabetic Munich Wistar Frömter rats with established chronic kidney disease (CKD). The gradual decline in kidney function in diabetic CKD is due to a thickening of glomerular and Bowman capsule basement membranes, mesangial matrix expansion, and tubulointerstitial fibrosis. In this study we aimed to characterize whether the renal protection of FIN is related to a decrease in kidney damage through histomorphological changes in diabetic MWF rats. Design and method: Diabetes was induced by a streptozotocin injection (15 mg/Kg, i.p.) together with exposure to a high fat/high sucrose (HF/HS) diet (MWF-D) for 6 weeks. The MWF-D-FIN group was additionally treated with 10 mg/Kg/day of FIN included in the HF/HS diet (n = 6/group). Morphometrical analysis of renal structural changes was performed under hematoxylin and eosin staining, and light microscopy. Matrix metalloproteinases (MMP)-2 and MMP-9 activities were determined by zymography. Results: MWF-D and MWF-D-EP rats exhibited significantly elevated glycemia, water intake, urine volume, glucosuria, and kidney weight compared to control MWF. Histological examination of kidney samples of MWF and MWF-D rats showed hypertrophic glomeruli with an increase of the glomerular tuft and the Bowman's space. These pathological alterations were prevented by FIN treatment. The percentage of glomerulosclerosis was significantly higher in MWF and MWF-D rats and 59% lower in the MWF-D-FIN group (p<0.001) whereas the glomerulosclerosis index was reduced to 33% by FIN (p<0.001). Moreover, MWF-D rats showed an increased interstitial inflammation index compared to MWF rats (p<0.001) which was reduced to 44% (p<0.001) in the MWF-D-FIN group. Since an increase in MMP-2 and MMP-9 activities are associated with fibrosis development, these were determined by zymography in kidney samples of all groups. Both MMP-2 and MMP-9 were significantly higher in MWF-D compared to MWF and decreased by FIN treatment. Conclusions: In conclusion FIN prevents the development of diabetic kidney damage due to a reduction in glomerular alterations and interstitial inflammation associated to an inhibition of MMP-2 and MMP-9 activities.

Mice with a Pax2 missense variant display impaired glomerular repair.

PAX2 regulates kidney development, and its expression persists in parietal epithelial cells (PECs), potentially serving as a podocyte reserve. We hypothesized that mice with a Pax2 pathogenic missense variant (Pax2A220G/+) have impaired PEC-mediated podocyte regeneration. Embryonic wild-type mouse kidneys showed overlapping expression of PAX2/Wilms' tumor-1 (WT-1) until PEC and podocyte differentiation, reflecting a close lineage relationship. Embryonic and adult Pax2A220G/+ mice have reduced nephron number but demonstrated no glomerular disease under baseline conditions. Pax2A220G/+ mice compared with wild-type mice were more susceptible to glomerular disease after adriamycin (ADR)-induced podocyte injury, as demonstrated by worsened glomerular scarring, increased podocyte foot process effacement, and podocyte loss. There was a decrease in PAX2-expressing PECs in wild-type mice after adriamycin injury accompanied by the occurrence of PAX2/WT-1-coexpressing glomerular tuft cells. In contrast, Pax2A220G/+ mice showed no changes in the numbers of PAX2-expressing PECs after adriamycin injury, associated with fewer PAX2/WT-1-coexpressing glomerular tuft cells compared with injured wild-type mice. A subset of PAX2-expressing glomerular tuft cells after adriamycin injury was increased in Pax2A220G/+ mice, suggesting a pathological process given the worse outcomes observed in this group. Finally, Pax2A220G/+ mice have increased numbers of glomerular tuft cells expressing Ki-67 and cleaved caspase-3 compared with wild-type mice after adriamycin injury, consistent with maladaptive responses to podocyte loss. Collectively, our results suggest that decreased glomerular numbers in Pax2A220G/+ mice are likely compounded with the inability of their mutated PECs to regenerate podocyte loss, and together these two mechanisms drive the worsened focal segmental glomerular sclerosis phenotype in these mice.NEW & NOTEWORTHY Congenital anomalies of the kidney and urinary tract comprise some of the leading causes of kidney failure in children, but our previous study showed that one of its genetic causes, PAX2, is also associated with adult-onset focal segmental glomerular sclerosis. Using a clinically relevant model, our present study demonstrated that after podocyte injury, parietal epithelial cells expressing PAX2 are deployed into the glomerular tuft to assist in repair in wild-type mice, but this mechanism is impaired in Pax2A220G/+ mice.

Chemoprotective and immunomodulatory potential of Lactobacillus reuteri against cadmium chloride-induced breast cancer in mice

IntroductionThe current study aimed to investigate the role of probiotic Lactobacillus reuteri for the treatment and prevention of breast cancer. Materials and methodsBreast cancer was induced by using Cadmium Chloride (Cd) (2 mg/kg) in group II. Tamoxifen was administered to group III. Group IV was treated with Lactobacillus reuteri. Group V was treated with Cd for one month and divided into three subgroups including VA, VB, and VC which were treated with tamoxifen, Lactobacillus reuteri, and tamoxifen + Lactobacillus reuteri, respectively. ResultsSignificantly higher levels of TNF-α (40.9 ± 4.2 pg/mL), IL-6 (28.0 ± 1.5 pg/mL), IL-10 (60.2 ± 2.0 pg/mL), IFN-γ (60.2 ± 2.0 pg/mL), ALAT (167.2 ± 6.2 U/l), ASAT (451.6 ± 13.9 U/l), and MDA (553.8 ± 19.6 U/l) was observed in Cd group. In comparison, significantly lower levels of TNF-α (18.0 ± 1.1 pg/mL), IL-6 (9.4 ± 0.4 pg/mL), IL-10 (20.8 ± 1.1 pg/mL), IFN-γ (20.8 ± 1.1 pg/mL), ALAT (85.2 ± 3.6 U/l), ASAT (185 ± 6.9 U/l), and MDA (246.0 ± 7.5 U/l) were observed in group Cd + Tam + LR. Liver histopathology of the Cd group showed hemorrhage and ductal aberrations. However, mild inflammation and healthier branched ducts were observed in treatment groups. Furthermore, the renal control group showed normal glomerular tufts, chronic inflammation from the Cd group, and relatively healthier glomerulus with mild inflammation in treatment groups. ConclusionHence, the preventive and anticancerous role of probiotic Lactobacillus reuteri is endorsed by the findings of the current study.

Glomerular Herniation in Toxemia of Pregnancy before 18 Weeks Gestation

Presentation of preeclampsia before 18 weeks is rare. We present a case of severe preeclampsia manifesting at 18 weeks gestation, notable with concurrent renal and optic changes. Beyond the typical kidney histological features of toxemia of pregnancy, the kidney biopsy revealed a distinctive histopathological finding-herniation of the glomerular tuft into the proximal tubule. This finding is rare with only a few cases reported in the literature. We present our findings for the early identification of preeclampsia. Additionally, our case exhibited severe retinal edema on fundoscopy, also offering a potential avenue for improving early detection. These insights are crucial for further exploration and understanding of these unique aspects of early preeclampsia just prior to retinal detachment.

Analysis of fetal renal cortex development: Cortical maturation index as a new potential guide in fetal renal cortex assessment

Background/Aim. To date, most of the scientific attention has been aimed at the morphometric analysis of the nephrogenic zone (NZ) of the fetal renal cortex, while the quantification and analysis of the maturation zone (MZ) and other indicators of renal maturity were missing. The aim of the study was to examine the characteristics of fetal kidney cortex maturation, as well as to propose the development of a new cortical maturity index (CMI). Methods. The study included 42 paraffin molds of the fetal kidney, divided into three groups according to gestational age (GA). After hematoxylin and eosin staining, tissue sections were analyzed through the following parameters: the thickness of the NZ and MZ, the renal corpuscles area (RCa) and the glomerular capillary tuft area (GCTa), and the maturation stages of the glomeruli. In addition, a new parameter, CMI, was formed as a ratio of NZ and MZ thickness. The collected data were statistically processed. Results. Changes in NZ and MZ thickness were statistically significant, and they correlated with GA. A value of CMI higher than 0.2 was recorded in the kidney samples of fetuses younger than the 20th gestational week (GW), while a value lower than 0.1 was recorded in the samples older than the 30th GW. With an increase in GA in all zones of the renal cortex, RCa and GCTa decreased. A statistically significant reduction of GCTa was observed in the oldest group in the juxtamedullary and intermediate zones of the cortex (p < 0.01). Glomeruli located in the deeper parts of the cortex were more mature than the superficial ones. Conclusion. The measured parameters can serve as a starting point for future studies that would analyze the histomorphological characteristics of the fetal kidney cortex. In the absence of clinical data, a newly formed parameter CMI can represent assistance with the determination of GA, as it significantly correlates with GA (p < 0.01).

Five-Year study on renal outcomes in biopsy-proven focal segmental glomerulosclerosis patients in Shiraz, Iran.

Focal segmental glomerulosclerosis (FSGS) is a prevalent glomerular disease that often leads to nephrotic syndrome. It is characterized by consolidating a portion of the glomerular capillary tuft connected to Bowman's capsule. This retrospective cohort study aimed to determine the demographic characteristics, risk factors, and prognostic indicators associated with FSGS in Shiraz, Iran. The study included 53 primary FSGS patients aged over 18 years who were referred to clinics affiliated with Shiraz University of Medical Sciences. Data were collected through a comprehensive data-gathering sheet encompassing demographic information, medical history, laboratory test results, and histopathological findings. Statistical analysis was performed using SPSS 18, considering a significance level of p<0.05. A five-year follow-up was conducted on the 53 patients, with the mean age of 41.0±13.3 years. The most common FSGS variants observed were "not otherwise specified" (NOS, 13.2%) and tip variant (7.5%). Older patients exhibited higher disease activity, whereas remission rates were higher among younger individuals (P=0.012). Patients achieving remission had lower creatinine and Pro/Cr ratios and higher glomerular filtration rates (p<0.05). Treatment involving a combination of corticosteroids and mycophenolate mofetil showed a significant correlation with remission (P=0.036). Older patients with higher creatinine levels, higher Pro/Cr ratios, and lower glomerular filtration rates at disease onset may require more aggressive treatment. Combination therapy with mycophenolate mofetil and corticosteroids yields better outcomes, leading to increased remission rates. These findings provide valuable insights for managing FSGS patients.

Kidney Injury by Unilateral Ureteral Obstruction in Mice Lacks Sex Differences

Introduction: Renal fibrosis is a critical event in the development and progression of chronic kidney disease (CKD), and it is considered the final common pathway for all types of CKD. The prevalence of CKD is higher in females; however, males have a greater prevalence of end-stage renal disease. In addition, low birth weight and low nephron number are associated with increased risk for CKD. This study examined the development and severity of unilateral ureter obstruction (UUO)-induced renal fibrosis in male and female wild-type (ROP +/+) and mutant (ROP Os/+) mice, a mouse model of low nephron number. Methods: Male and female ROP +/+ and ROP Os/+ mice were subjected to UUO, and kidney tissue was collected at the end of the 10-day experimental period. Kidney histological analysis and mRNA expression determined renal fibrosis, tubular injury, collagen deposition, extracellular matrix proteins, and immune cell infiltration. Results: Male and female UUO mice demonstrated marked renal injury, kidney fibrosis, and renal extracellular matrix production. Renal fibrosis and α-smooth muscle actin were increased to a similar degree in ROP +/+ and ROP Os/+ mice with UUO of either sex. There were also no sex differences in renal tubular cast formation or renal infiltration of macrophage in ROP +/+ and ROP Os/+ UUO mice. Interestingly, renal fibrosis and α-smooth muscle actin were 1.5–3-fold greater in UUO-ROP +/+ compared to UUO-ROP Os/+ mice. Renal inflammation phenotypes following UUO were also 30–45% greater in ROP +/+ compared to ROP Os/+ mice. Likewise, expression of extracellular matrix and renal fibrotic genes was greater in UUO-ROP +/+ mice compared to UUO-ROP Os/+ mice. In contrast to these findings, ROP Os/+ mice with UUO demonstrated glomerular hypertrophy with 50% greater glomerular tuft area compared to ROP +/+ with UUO. Glomerular hypertrophy was not sex-dependent in any of the genotypes of ROP mice. These findings provide evidence that low nephron number contributes to UUO-induced glomerular hypertrophy in ROP Os/+ mice but does not enhance renal fibrosis, inflammation, and renal tubular injury. Conclusion: Taken together, we demonstrate that low nephron number contributes to enhanced glomerular hypertrophy but not kidney fibrosis and tubular injury. We also demonstrate that none of the changes caused by UUO was affected by sex in any of the ROP mice genotypes.