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Diabetic nephropathy is the leading cause of end-stage kidney disease, and the association between impaired autophagy and kidney structure damage in diabetes is well known. Diets enriched with polyunsaturated fatty acids (PUFAs) have been the subject of numerous studies on preventing and treating various metabolic disorders. The results of these studies suggest that n-3 PUFA may have a renoprotective effect, reducing the structural damage to the kidneys associated with DM. We hypothesized that the activation of autophagy partly mediates the potential protective effect of n-3 PUFA on diabetic kidneys. Wistar rats were randomly divided into four groups according to the type of diet: control (C) and diabetic (STZ) groups received food including 0.5 % linseed oil and 2 % sunflower oil with an n-6/n-3 ratio of 7; the STZ+N6 group received a diet with 2.5 % sunflower oil with an n-6/n-3 ratio of 60; and the STZ+N3 group received a diet containing 2.5 % fish oil with an n-6/n-3 ratio of 1, with the addition of eicosapentaenoic acid (EPA) and 19 % docosahexaenoic acid (DHA). All rats, except for those in the C group, had diabetes induced by an intraperitoneal injection of streptozotocin. We conducted histological and immunohistochemical assessments to determine the effects of different n-6/n-3 PUFA dietary ratios on the expression levels of different autophagy markers in the kidney of the rats. The results indicate significant effects of n-3 and n-6 PUFA supplementation on the expression of different autophagy markers in the renal cortex of the diabetic rats. In particular, n-6 PUFA supplementation increased LC3B expression while simultaneously decreasing Rab7 expression; meanwhile, n-3 PUFA supplementation resulted in a decreased expression of LAMP2A and Rab7. Moreover, n-3 PUFA supplementation prevented an increase in BECL1 and p62, that was observed in kidneys from diabetic and diabetic n-3 supplemented animals. These results point to the complex interactions of fatty acids and autophagy during the development of diabetic kidney disease, which should be taken into account in future therapeutic approaches., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Autophagy is the primary intracellular degradation system, and it plays an important role in many biological and pathological processes. Studies of autophagy involvement in developmental processes are important for understanding various processes. Among them are fibrosis, degenerative diseases, cancer development, and metastasis formation. Diabetic kidney disease is one of the main causes of chronic kidney disease and end-stage renal failure. The aim of this study was to investigate the immunohistochemical expression patterns of LC3B, LAMP2A, and GRP78 during different developmental stages of early-developing human kidneys and in samples from patients with type II diabetes mellitus. During the 7/8th DW, moderate expression of LC3B and LAMP2A and strong expression of GRP78 were found in the mesonephric glomeruli and tubules. In the 9/10th DW, the expression of LC3B and LAMP2A was even more pronounced in the mesonephric tubules. LC3B, LAMP2A, and GRP78 immunoreactivity was also found in the paramesonephric and mesonephric ducts and was stronger in the 9/10th DW compared with the 7/8th DW. In addition, the expression of LC3B, LAMP2A, and GRP78 also appeared in the mesenchyme surrounding the paramesonephric duct in the 9/10th DW. In the 15/16th DW, the expression of LC3B in the glomeruli was weak, that of LAMP2A was moderate, and that of GRP78 was strong. In the tubuli, the expression of LC3B was moderate, while the expression of LAMP2A and GRP78 was strong. The strongest expression of LC3B, LAMP2A, and GRP78 was observed in the renal medullary structures, including developing blood vessels. In postnatal human kidneys, the most extensive LC3B, LAMP2A, and GRP78 expression in the cortex was found in the epithelium of the proximal convoluted tubules, with weak to moderate expression in the glomeruli. The medullary expression of LC3B was weak, but the expression of LAMP2A and GRP78 was the strongest in the medullary tubular structures. Significantly lower expression of LC3B was found in the glomeruli of the diabetic patients in comparison with the nondiabetic patients, but there was no difference in the expression of LC3B in the tubule-interstitial compartment. The expression of LAMP2A was significantly higher in the tubule-interstitial compartments of the diabetic patients in comparison with the nondiabetic patients, while its expression did not differ in the glomeruli. Extensive expression of GRP78 was found in the glomeruli and the tubule-interstitial compartments, but there was no difference in the expression between the two groups of patients. These data give us new information about the expression of LC3B, LAMP2A, and GRP78 during embryonic, fetal, and early postnatal development. The spatiotemporal expression of LC3B, LAMP2A, and GRP78 indicates the important role of autophagy during the early stages of renal development. In addition, our data suggest a disturbance in autophagy processes in the glomeruli and tubuli of diabetic kidneys as an important factor in the pathogenesis of diabetic kidney disease.

Kidney failures in infants are mostly caused by congenital anomalies of the kidney and urinary tract (CAKUT), which are among the most common congenital birth disorders worldwide when paired with cardiac abnormalities. People with CAKUT often have severe kidney failure as a result of a wide range of abnormalities that can occur alone or in conjunction with other syndromic disorders. In this study, we aimed to investigate the expression pattern of CAKUT candidate genes alpha-8 integrin (ITGA8) and Van Gogh-like 2 (VANGL2) in fetal tissues of healthy and CAKUT-affected kidneys using immunohistochemistry and immunofluorescence. We found that under CAKUT circumstances, the expressions of ITGA8 and VANGL2 are changed. Additionally, we showed that VANGL2 expression is constant during fetal aging, but ITGA8 expression varies. Moreover, compared to normal healthy kidneys (CTRL), ITGA8 is poorly expressed in duplex kidneys (DKs) and dysplastic kidneys (DYS), whereas VANGL2 is substantially expressed in dysplastic kidneys (DYS) and poorly expressed in hypoplastic kidneys (HYP). These results point to VANGL2 and ITGA8 as potential prognostic indicators for CAKUT malformations. Further research is necessary to explore the molecular mechanisms underlying this differential expression of ITGA8 and VANGL2.

The purpose of this study was to evaluate the spatiotemporal immunoexpression pattern of microtubule-associated protein 1 light chain 3 beta (LC3B), glucose-regulated protein 78 (GRP78), heat shock protein 70 (HSP70), and lysosomal-associated membrane protein 2A (LAMP2A) in normal human fetal kidney development (CTRL) and kidneys affected with congenital anomalies of the kidney and urinary tract (CAKUT). Human fetal kidneys (control, horseshoe, dysplastic, duplex, and hypoplastic) from the 18th to the 38th developmental week underwent epifluorescence microscopy analysis after being stained with antibodies. Immunoreactivity was quantified in various kidney structures, and expression dynamics were examined using linear and nonlinear regression modeling. The punctate expression of LC3B was observed mainly in tubules and glomerular cells, with dysplastic kidneys displaying distinct staining patterns. In the control group's glomeruli, LAMP2A showed a sporadic, punctate signal; in contrast to other phenotypes, duplex kidneys showed significantly stronger expression in convoluted tubules. GRP78 had a weaker expression in CAKUT kidneys, especially hypoplastic ones, while normal kidneys exhibited punctate staining of convoluted tubules and glomeruli. HSP70 staining varied among phenotypes, with dysplastic and hypoplastic kidneys exhibiting stronger staining compared to controls. Expression dynamics varied among observed autophagy markers and phenotypes, indicating their potential roles in normal and dysfunctional kidney development.

Approximately half of the cases of chronic kidney disease (CKD) in childhood are caused by congenital anomalies of the kidney and urinary tract (CAKUT). Specific genes were identified as having significant importance in regard to the underlying genetic factors responsible for the CAKUT phenotype, and in our research, we focused on analyzing and comparing the expression levels of ectodysplasin A2 receptor (EDA2R), protocadherin9 (PCDH9), and TNF receptor-associated factor 7 (TRAF7) proteins in the cortex and medulla of healthy control kidneys during developmental phases 2, 3, and 4. We also performed an analysis of the area percentages of the mentioned proteins in the cortical and medullary sections of healthy embryonic and fetal kidneys compared to those affected by CAKUT, including duplex kidneys (DK), horseshoe kidneys (HK), hypoplastic kidneys (HYP), and dysplastic kidneys (DYS). We found that the CAKUT candidate gene proteins EDA2R, PCDH9, and TRAF7 are all expressed during normal human kidney development stages. In DYS, the expression of EDA2R was higher than in normal kidneys, likely due to EDA2R's role in apoptosis, which was upregulated in specific cases and could possibly contribute to the formation of DYS. The expression of PCDH9 was lower in HK, which can be attributed to the possible role of PCDH9 in cell migration suppression. Decreased PCDH9 expression is linked to increased cell migration, potentially contributing to the development of HK. The level of TRAF7 expression was reduced in all examined kidney disorders compared to normal kidneys, suggesting that this reduction might be attributed to the crucial role of TRAF7 in the formation of endothelium and ciliogenesis, both of which are essential for normal kidney development. Further research is required to ascertain the function of these proteins in both the typical development of the kidney and in CAKUT.

The purpose of this study was to compare the immunofluorescence patterns of autophagic markers: Light chain 3 beta (LC3B), Glucose regulating protein 78 (GRP78), Heat shock cognate 71 (HSC70) and Lysosomal-associated membrane protein 2A (LAMP2A) in the developing and postnatal kidneys of Dab1 -/- ( yotari ) mice to those of wild-type samples. Embryos were obtained on gestation days 13.5 and 15.5 (E13.5 and E15.5), and adult animals were sacrificed at postnatal days 4, 11 and 14 (P4, P11, and P14). After fixation and dehydration, paraffin-embedded kidney tissues were sectioned and incubated with specific antibodies. Using an immunofluorescence microscope, sections were analyzed. For statistical analysis, a two-way ANOVA test and a Tukey's multiple comparison test were performed with a probability level of p < 0.05. A significant increase in GRP78 and LAMP2A expression was observed in the renal vesicles and convoluted tubules of yotari in embryonic stages. In postnatal kidneys, all observed proteins showed higher signal intensities in proximal and distal convoluted tubules of yotari , while a higher percentage of LC3B-positive cells was also observed in glomeruli. Our findings suggest that all of the examined autophagic markers play an important role in normal kidney development, as well as the potential importance of these proteins in renal pathology, where they primarily serve a protective function and thus may be used as diagnostic and therapeutic targets.

The aim of this study was to determine the effects of altered ganglioside composition on the expression of Cx37, Cx40, Cx43, Cx45, and Panx1 in different kidney regions of St8sia1 gene knockout mice ( St8sia1 KO) lacking the GD3 synthase enzyme. Experiments were performed in twelve male 6-month-old mice: four wild-type (C57BL/6-type, WT) and eight St8sia1 KO mice. After euthanasia, kidney tissue was harvested, embedded in paraffin wax, and processed for immunohistochemistry. The expression of connexins and Panx1 was determined in different regions of the kidney: cortex (CTX.), outer stripe of outer medulla (O.S.), inner stripe of outer medulla (IN.S.), and inner medulla (IN.MED.). We determined significantly lower expression of Cx37, Cx40, Cx45, and Panx1 in different parts of the kidneys of St8sia1 KO mice compared with WT. The most consistent decrease was found in the O.S. where all markers (Cx 37, 40, 45 and Panx1) were disrupted in St8si1 KO mice. In the CTX. region, we observed decrease in the expression of Cx37, Cx45, and Panx1, while reduced expression of Cx37 and Panx1 was more specific to IN.S. The results of the present study suggest that deficiency of GD3 synthase in St8sia1 KO mice leads to disruption of renal Cx expression, which is probably related to alteration of ganglioside composition.

This study aimed to explore how Dab1 gene functional silencing influences the spatial and temporal expression patterns of fibroblast growth factor receptor 1 (FGFR1), fibroblast growth factor receptor 2 (FGFR2), receptor-interacting protein kinase 5 (RIP5), and huntingtin-interacting protein 2 (HIP2) in the developing and postnatal kidneys of the yotari mice as potential determinants of normal kidney formation and function. Dab1 -/- animal kidneys exhibit diminished FGFR1/FGFR2 expression in all examined developmental stages, whereas RIP5 cell immunoreactivity demonstrated negligible variation. The HIP2 expression revealed a discernible difference during the postnatal period, where we noted a significant decrease in almost all the observed kidney structures of yotari animals. An extracellular signal-regulated kinase (Erk1/2) and mammalian target of rapamycin (mTOR) expression in yotari kidneys decreased in embryonic and postnatal developmental phases for which we can hypothesize that the Erk1/2 signaling pathway in the yotari mice kidneys is dependent on Reelin with Dab1 only partially implicated in Reelin-mediated MEK/Erk1/2 activation. The impairment of FGFR1 and FGFR2 expression suggests the involvement of the observed markers in generating the CAKUT phenotype resulting in renal hypoplasia. Our study demonstrates the critical role of HIP2 in reducing cell death throughout nephrogenesis and maturation in wild-type mice and indicates a possible connection between decreased HIP2 expression in postnatal kidney structures and observed podocyte injury in yotari . Our results emphasize the crucial function of the examined markers throughout normal kidney development and their potential participation in kidney pathology and diagnostics, where they might serve as biomarkers and therapeutic targets.

The comparative effects of the two commonly used antidiabetic drugs metformin and liraglutide on renal pathology and expression of connexin 45 (Cx45) and pannexin 1 (Panx1) in adult obese rats fed high-fat high-sugar diet (HFHSD) were studied. Considering recent data on the profound influence of sex on metformin and liraglutide effects, we compared the effects of both drugs between male and female animals. 44-week-old Sprague-Dawley rats were separated into 4 groups that were fed: standard diet, HFHSD, HFHSD treated with metformin (s.c., 50 mg/kg/day) and HFHSD treated with liraglutide (s.c., 0.3 mg/kg/day). Treatment with metformin or liraglutide lasted for 14 weeks. Histology and immunohistochemistry were performed to quantify renal pathological changes and Cx45 and Panx1 expression. HFHSD caused thickening of the Bowman's capsule (BC). Both metformin and liraglutide failed to ameliorate the BC thickening; metformin even worsened it. Effects on the tubulointerstitial fibrosis score, BC thickness and Cx45 and Panx1 expression were sex-dependent. We found a 50% increase in mitochondria in proximal tubules of metformin- and liraglutide-treated HFHSD-fed rats, but these effects were not dependent on the sex. This is a first study showing that the effects of metformin and liraglutide on kidney pathology in rats fed HFHSD are mostly sex-dependent and that these effects are not necessarily beneficial. Both drugs changed the Cx45 and Panx 1 expression; hence their effects could be related to amelioration of disruptions in intercellular communication., (Copyright © 2021 Elsevier GmbH. All rights reserved.)

We studied the expression of mismatch repair genes (MMRs)-mutS protein homolog 2 (MSH2), PMS2, MutL homolog 1 (MLH1), and yH2AFX in diabetic rat kidneys. Streptozotocin-induced diabetes mellitus type 1 rat model (DM1) was used. Renal samples were collected 2 weeks and 2 months after DM1 induction and immunohistochemical expression of MMR genes in the renal cortex was analyzed. Diabetic animals showed lower MSH2 and higher yH2AFX kidney expression both 2 weeks and 2 months after DM1 induction. MLH1 expression significantly increased 2 weeks after DM1 induction (P<0.0001). The most substantial differences were observed in the period 2 weeks after induction, with lower MSH2 and higher MLH1 expression in the proximal convoluted tubules and distal convoluted tubules (DCT) of diabetic animals (P<0.001). yH2AFX expression significantly increased in the DCT of diabetic animals at both time points (P<0.001; P<0.01). PMS2 expression changed only in the glomeruli, where it significantly decreased 2 months after DM1 induction (P<0.05). We concluded that the most substantial changes in renal expression of MMRs are happening already 2 weeks after diabetes induction, predominantly in the proximal convoluted tubules and DCT. Moreover, DCT could have a critical role in the pathophysiology of diabetic nephropathy (DN) and might be a future therapeutic target in this condition. The obtained results point to the MMRs as a potential factor in the development and progression of DN, as well as the possible link between DN and renal carcinogenesis., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Aim: One of the main causes of end-stage renal disease (ESRD) in the world is IgA nephropathy (IgAN). Since kidney is a key player in vitamin D metabolism, we investigated the expression of renal vitamin D receptors (VDR) and metabolizing enzymes in IgA nephropathy patients (IgAN-P)., Methods: The sample included twelve IgAN-P who underwent ultrasound-guided renal biopsies and five controls who underwent nephrectomy due to clear renal carcinoma. Immunofluorescent staining was used to determine the expression of VDR, 25-hydroxyvitamin D3 -alpha-hydroxylase (1alpha-OHase) and vitamin D3 24-hydroxylase (CYP24A1)., Results: Significant increase in expression of VDR, which was prominent in distal tubular cells (DTCs) in tissues from IgAN-P, was found in comparison to the controls (p = 0.0368). The expression of 1alpha-OHase, calcitriol synthesizing enzyme, was significantly lower in IgAN-P, in comparison with controls (p < 0.0001). The opposite, expression of CYP24A1 (vitamin D degrading enzyme), was significantly higher in IgAN-P in comparison with controls (p = 0.0003). Additionally, we found significant negative correlation between percentage of CYP24A1 immunoreactive nuclei in proximal tubular cells (PTCs) and estimated glomerular filtration rate (eGFR) in IgAN-P (r = -0.6139; p = 0.0337)., Conclusions: Our research indicates substantially decreased renal calcitriol production and increased vitamin D degradation in kidneys of IgAN-P, but larger studies are needed to confirm our results., (Copyright © 2021 Elsevier GmbH. All rights reserved.)

BACKGROUND Renal parenchymal damage and scarring usually is associated with urinary tract infection (UTI), whereas the impact of vesicoureteral reflux (VUR) on the kidneys is unclear. We aimed to compare kidneys with all grades of VUR (grades Io-V) and those without VUR by using direct radionuclide cystography, voiding cystourethrography, and findings from 99mTc-DMSA scintigraphy (DMSA scan). MATERIAL AND METHODS The present analysis included 253 renal ureteral units (RUU) from 129 children with VUR and recurrent UTI and children with a single febrile UTI associated with abnormal ultrasonographic findings. The 6 grades of VUR (Io, I, II, III, IV, and V) and 35 RUUs without VUR were divided into 4 groups: 1. Non-dilated VUR (grades Io-II); 2. Mildly dilated VUR (grade III); 3. Dilated VUR (grades IV-V); and 4. The control group. RESULTS DMSA scanning showed significant differences between the groups with non-dilated VUR, grade III VUR, grades IV-V VUR, and the control group in kidney width (χ²=30.5; P<0.001); position and shape (χ²=30.6; P<0.001); intensity of activity (χ²=38.1; P<0.001); distribution of activity (χ²=34.5; P<0.001); and existence of scars (χ²=16; P<0.001). The probability of abnormalities on DMSA scans increased with the VUR grade. However, inside the groups of dilated and non-dilated VUR we found no significant statistical differences between those characteristics. CONCLUSIONS Our results indicate that kidneys without VUR or with non-dilated lateral VUR and dilated VUR on the contralateral side represent 2 different categories of parenchymal changes.

Background: Aim of our study is to provide an insight into the genetic expression landscape of GREB1L, ITGA10 and CRELD2 which are important in human genitourinary tract development which might help elucidate the critical stages for the onset of kidney anomalies., Methods: Morphological parameters were analyzed using immunohistochemistry on human foetal (13-38 w) and postnatal (1.5 and 7.5y) human kidney samples., Results: GREB1L marker had a strong intensity and the highest rate in proximal tubules (PTC) of 1.5 years' kidney (90.25%). In the distal tubules (DCT) there were statistically significant differences in 13 w, 15 w, 16 w, 21 w, 38 w and 7.5y regarding 1.5y (Kruskal-Wallis test, p < 0.001). There was significantly more GREB1L in the glomeruli at 21 w and 38 w in regard to all other stages (Kruskal-Wallis test, p < 0.01). ITGA10 staining intensity was strongest in PCT with the highest rate in 13 w (92.75%), while the lowest rate was found in glomeruli and DCT (Kruskal-Wallis test, p < 0.001). CRELD2 had the strongest staining intensity in PCT with the highest rate in 13 w and 1.5y (92.25%) and lowest in the glomeruli of 7.5 years (24.3 %). In DCT there were statistically significant differences in CRELD2 positive cells in 13 w, 15 w, 16 w, 21 w, 38 w and 7.5y regarding 1.5y (Kruskal-Wallis test, p < 0.01). ITGA10 and CRELD2 co-localised in the postnatal period in DCT., Conclusion: High kidney expressions of GREB1L, ITGA10 and CRELD2 even in the postnatal period implicate their importance not only for the onset of CAKUT in the case of their mutation but also for maintenance of kidney homeostasis., (Copyright © 2021 Elsevier GmbH. All rights reserved.)

The purpose of this study was to determine the changes in the expression of sigma 1 receptors (σ1Rs) in the kidney of diabetic rats, which could indicate their possible role in the pathogenesis of diabetic nephropathy (DN). Sprague-Dawley rats were were given intraperitoneal injection of 55 mg/kg streptozotocin (STZ) in order to induce type I of diabetes (DM1). Control and diabetic rats were sacrificed 2 weeks or 2 months after DM1 induction. Expression of σ1Rs was determined in kidneys of the experimental rats, using immunohistochemistry. The most prominent expression of σ1Rs was found in distal tubuli (DT). Results have shown significant increase in renal σ1Rs section percentage area of rats 2 months after DM1 induction, compared to both control group at the same age and diabetic group 2 weeks after induction (P < 0.01 both). Similarly, a number of immunoreactive DT increased in diabetic group 2 months after induction, compared to DM1 group 2 weeks after induction (P < 0.001). We also found a decrease of a number of immunoreactive DT 2 weeks post DM1 induction (P < 0.01). However, the same was found during maturation of the control rats (P < 0.001). In addition, a strong co-expression of σ1R and proinflammatory factor TGFβ was seen in vacuolated DT. The results indicate to the potential role of σ1Rs in postnatal maturation of the rat kidneys and in distal tubular damage in the pathogenesis of the diabetic nephropathy. We conclude that σ1Rs could be potential target in treatment of the diabetic nephropathy., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 Elsevier GmbH. All rights reserved.)

In diabetic nephropathy (DN), intercellular communication is disrupted. Connexins (Cx) have a crucial role in that process. Dietary ratios and supplementation with polyunsaturated fatty acids (PUFAs) can alleviate diabetic complications and cause alterations in Cx levels. Although pannexins (Panx) share similarities with members of the Cx family, their function in diabetic nephropathy has still not been fully determined. We studied the influence of PUFA supplementation on the immunoexpression of Px1 and Cx family members in diabetic kidneys of rats. Four groups of rats in experimental DM1 model were supplemented with different dietary n-6/n-3 ratios; ≈7 in control (C) and diabetic groups (STZ), ≈ 60 in the STZ + N6 group and ≈ 1 (containing 16% EPA and 19% DHA) in the STZ + N3 group. Immunoexpression of Cx40, Cx43, Cx45 and Panx1 was evaluated in the renal tissue of diabetic rats using immunohistochemistry. Diabetes significantly decreased the protein expression of Cx40 and Cx43 and increased Panx1 protein expression in the renal cortex (p < 0.05-p < 0.01). There was a significant impact of diet on Cx and Panx1 immunoexpression. Dietary supplementation with a high n-6/n-3 ratio downregulated the protein expression of Cx45 and Panx1 in diabetic rats (p < 0.05-p < 0.01), while Cx43 immunoexpression was increased in diabetic rats fed with high and low n-6/n-3 ratios (p < 0.01-p < 0.001). Hyperglycaemic conditions in DN interfere with cell-to-cell communication and disturb the connection between cells and their immediate environment due to variations in connexin and pannexin immunoexpression. These variations can be regulated by PUFA dietary intake, suggesting their beneficial effect and possible therapeutic option.

Background: Information about renal diseases in children is available from national registries of renal biopsies. Aim of the study was to compare the clinical presentation of glomerular diseases and tubulointerstitial space diseases with pathohistological diagnosis of indicated renal biopsies from pediatric population in the Croatian region of Dalmatia., Methods: Out of 231 pediatric patients with suspected glomerular and tubulointerstitial diseases, 54 underwent ultrasound-guided renal biopsy at University Hospital of Split. Kidney allograft biopsy, and re-biopsy were excluded. The biopsy sections were examined under light microscopy, immunofluorescence and electron microscopy. The data was reviewed to determine the pathohistological spectrum and clinicopathologic correlations. We retrospectively analyzed kidney biopsy data from 2008 to 2017 and compared them to that between 1995 and 2005., Results: The mean age of patients was 9.84 ± 5.4 years. Male:female ratio was 1.2:1. The main indications for biopsy were pure nephrotic syndrome without hematuria (25.9%), non-nephrotic proteinuria with haematuria (22.2%), nephritic syndrome with nephrotic proteinuria (18.5%), and isolated hematuria (16.7%). The most common pathohistological findings were IgA nephropathy (IgAN, 24.1%), minimal change disease (MCD, 16.7%), Henoch-Schönlein purpura glomerulonephritis (HSPN, 14.8%), Alport syndrome and focal segmental glomerulosclerosis (AS and FSGS, 11.1% each), tubulointerstitial nephritis and membranous glomerulopathy (TIN and MGN, 3.7% each), while other cases were diagnosed rarely., Conclusions: Changes in epidemiology of renal diseases in children between the analyzed periods showed an increasing trend of IgAN, MCD, HSPN, AS and FSGS, while mesangioproliferative glomerulonephritis (MesPGN) and endoproliferative glomerulonephritis (EDGN) showed a decreasing trend that can be explained with the new pathohistological classification.

Aim: To explore the spatial and temporal expression patterns of DAB1 and Reelin in the developing and postnatal healthy human kidneys as potential determinants of kidney development., Methods: Paraffin-embedded fetal kidney tissue between the 13/14th and 38th developmental weeks (dw) and postnatal tissue at 1.5 and 7 years were stained with DAB1 and Reelin antibodies by double immunofluorescence., Results: During the fetal kidney development and postnatal period, DAB1 and Reelin showed specific spatial expression pattern and diverse fluorescence intensity. During the fetal period, DAB1 was strongly expressed in the distal convoluted tubules (DCT), with strong reactivity, and diversely in the proximal convoluted tubules (PCT) and glomeruli. In the postnatal period, DAB1 expression decreased. The strongest Reelin expression in early fetal stages was observed in the PCT. In the postnatal period, Reelin expression decreased dramatically in all observed structures. These two markers were colocalized during early developmental stages, mostly in PCT, DCT, and podocytes., Conclusion: The appearance of DAB1 and Reelin during fetal kidney development confirms their potential significant role in the formation of kidney structure or function. High DAB1 expression in the DCT implies its regulatory role in tubular formation or function maintenance during development. Reelin was highly expressed in human kidneys at early fetal stages, mostly in the PCT, while at later fetal stages and postnatal period its expression decreased.

Aim: Present study analyses the co-localisation of RIP5 with FGFR1, FGFR2 and HIP2 in the developing kidney, as RIP5 is a major determinant of urinary tract development, downstream of FGF-signaling., Methods: Paraffin embedded human kidney tissues of 16 conceptuses between the 6th-22th developmental week were analysed using double-immunofluorescence method with RIP5/FGFR1/FGFR2 and HIP2 markers. Quantification of positive cells were performed using Kruskal-Wallis test., Results: In the 6th week of kidney development RIP5 (89.6%) and HIP2 (39.6%) are strongly expressed in the metanephric mesenchyme. FGFR1 shows moderate/strong expression in the developing nephrons (87.3%) and collecting ducts (70.5%) (p < 0.05). RIP5/FGFR1 co-localized at the marginal zone and the ureteric bud with predominant FGFR1 expression. FGFR2 (26.1%) shows similar expression pattern as FGFR1 (70.5%) in the same kidney structures. RIP5/FGFR2 co-localized at the marginal zone and the collecting ducts (predominant expression of FGFR2). HIP2 is strongly expressed in collecting ducts (96.7%), and co-localized with RIP5. In 10th week, RIP5 expression decrease (74.2%), while the pattern of expression of RIP5 and FGFR1 in collecting ducts (33.4% and 91.9%) and developing nephrons (21.9% and 32.4%) (p < 0.05) is similar to that in the 6th developmental week. Ureter is moderately expressing RIP5 while FGFR1 is strongly expressed in the ureteric wall. FGFR2 is strongly expressed in the collecting ducts (84.3%) and ureter. HIP2 have 81.1% positive cells in the collecting duct. RIP5/FGFR1 co-localize in collecting ducts and Henley's loop., Conclusions: The expression pattern of RIP5, FGFR1, FGFR2 and HIP2 in the human kidney development might indicate their important roles in metanephric development and ureteric muscle layer differentiation through FGF signaling pathways., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Ciliogenesis in developing and post-natal human kidneys appears to influence cell proliferation and differentiation, apico-basal cell polarity, and tubular lumen formation. We have analyzed the appearance of primary cilia and differentiation of kidney cells in ten human conceptuses aged 6-22 weeks and in one 5-year-old kidney, using a double immunofluorescence labeling technique for α-tubulin, γ-tubulin, Oct-4, and Ki-67 and by electron microscopy. Immature forms of nephrons and ampullae were characterized by intense cell proliferation, which subsequently decreased during development. Primary cilia appeared on the surfaces of non-proliferating cells in developing nephrons, gradually increasing in length from 0.59 μm in renal vesicles to 0.81 μm in the S-forms of nephrons, ultimately reaching 3.04 μm in length in mature fetal and post-natal nephrons. Ciliary length increased from 0.59 μm in ampullae to 1.28 μm in post-natal collecting tubules. Mesenchymal to epithelial transformation of kidney cells coincided with the appearance of apico-basal polarity, both gap and tight junctions, and lumen formation. Up-regulation of Oct-4 expression correlated with the onset of kidney cell differentiation. Our results demonstrate the importance of proper primary cilia lengthening and Oct-4 expression for the normal development of fetal and post-natal kidneys and of apico-basal polarity for normal tubular lumen formation. Disturbances in these processes are associated with ciliopathies.

Background: Homeostasis of proliferating tissues is strongly dependent on intact DNA. Both neoplastic and non-neoplastic diseases have been associated with MSH2 (MutS homolog 2, a mismatch repair protein) deficiency. In this study, we examined how age and diabetes mellitus influence the expression of MSH2 in the kidney. Methods: To study the effect of age, three groups of healthy rats were formed: 2 months, 8 months, and 14 months old. Two groups of diabetic rats were formed: 8 months old and 14 months old. Expression of MSH2 in the kidney was studied by quantifying immunofluorescent staining. Results: Age was identified as the main factor that influences MSH2 expression in kidneys. The effect of age followed parabolic dynamics, with peak expression at 8 months of age and similar levels at 2 and 14 months. Diabetes had an age-dependent effect, which manifested as the increase of MSH2 expression in 14-month-old diabetic rats in comparison to healthy animals. Conclusions: Age influences MSH2 expression in the kidney more than diabetes mellitus. Since ageing is a risk factor for kidney neoplasia, downregulation of MSH2 in older rats might represent one of the pro-oncogenic mechanisms of ageing at a molecular level. [ABSTRACT FROM AUTHOR]

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Numerous evidence corroborates roles of gap junctions/hemichannels in proper kidney development. We analyzed how Dab1 gene functional silencing influences expression and localization of Cx37, Cx40, Cx43, Cx45, Panx1 and renin in postnatal kidneys of yotari mice, by using immunohistochemistry and electron microscopy. Dab1 Δ102/221 might lead to the activation of c-Src tyrosine kinase, causing the upregulation of Cx43 in the medulla of yotari mice. The expression of renin was more prominent in yotari mice (p < 0.001). Renin granules were unusually present inside the vascular walls of glomeruli capillaries, in proximal and distal convoluted tubules and in the medulla. Disfunction of Cx40 is likely responsible for increased atypically positioned renin cells which release renin in an uncontrolled fashion, but this doesn't rule out simultaneous involvement of other Cxs, such as Cx45 which was significantly increased in the yotari cortex. The decreased Cx37 expression in yotari medulla might contribute to hypertension reduction provoked by high renin expression. These findings imply the relevance of Cxs/Panx1 as markers of impaired kidney function (high renin) in yotari mice and that they have a role in the preservation of intercellular signaling and implicate connexopathies as the cause of premature death of yotari mice. [ABSTRACT FROM AUTHOR]

In present study we investigated expression pattern of the special tissue markers. SATB1 and PTEN to evaluate possible influence in pathophysiology and development of various biopsy proven kidney diseases. The 32 kidney biopsy samples were analysed using light, immunofluorescence and electron microscopy. There were 19 samples in proliferative and 13 samples in non- proliferative group of renal diseases. As control group, 9 specimens of healthy kidney tissue taken after surgery of kidney tumour were used. SATB1 and PTEN markers were used for immunofluorescence staining. Analysed tissue structures were glomeruli, proximal convoluted tubules (PCT) and distal convoluted tubules (DCT). The number of SATB1 and PTEN cells were calculated and the data compared between kidney structures, disease groups and control specimens. Both markers were positive in all investigated kidney structures, with expression generally, more prominent in tubular epithelial cells than in glomeruli, with the highest staining intensity rate as well as highest rate of both markers in DCT of proliferative diseases group (SATB1 64.5 %, PTEN 52 %). There was statistically significant difference in SATB1 expression in all tissue structures of interest in proliferative as well as non- proliferative group compared to control group (p < 0.01-p < 0.0001). PTEN expression were found significantly decreased in PCT of both disease groups in regard to control (PTEN 25.3 % and 23.8 % vs. 41.1 % (p < 0.01 and p < 0.001 respectively). SATB1 and PTEN could be considered as markers influenced in kidney disease development. SATB1/PTEN expression should be further investigated as useful markers of kidney disease activity as well as potential therapeutic target. [ABSTRACT FROM AUTHOR]