Glomerular Membrane Research Articles

Rats kidney morphological particularities and functions post-treatment with vernonia amygdalina extract and low-dose lead acetate

This study was conducted to evaluate the effect of Vernonia amygdalina extract on Pb-induced kidney toxicity in Wistar rats. This investigation was carried out using 25 Wistar rat of both sexes, and the animals were divided into five groups: 5 rats per group. Group A served as the negative control group and was orally gavaged with 5mg/ kg body weight of normal saline daily. Group B served as the positive control and was treated with daily intraperitoneal (IP) injection of 8 mg/kg body weight of Pb acetate (Pb). Group C was treated with daily intraperitoneal (IP) injection of 8 mg/kg body weight of Pb along with 20 mg/kg body weight of Vernonia amygdalina extract orally. Group D was treated with daily intraperitoneal (IP) injection of 8 mg/kg body weight of Pb along with 40 mg/kg body weight of Vernonia amygdalina extract orally. Group 5 was treated with daily intraperitoneal (IP) injection of 8 mg/kg body weight of Pb along with 60 mg/kg body weight of Vernonia amygdalina extract orally. All treatments were done for a period of 28 days. The animals were sacrificed on the 29th day by cervical dislocation, then blood was collected by cardiac puncture, and kidneys were collected for histological profile. Lipid peroxidation (MDA), creatinine and urea level were all determined. There was marked elevation in MDA level with a concomitant depletion in urea and creatinine content in the group treated with only Pb when compared with the negative control group. There was a significant increase in proximal tubular area, distal tubular area, glomerular membrane thickness, area, perimeter and feret’s diameter and a significant decrease in proximal tubule, distal tubule ratio and cellularity in this group of rats when compared to the negative control. Oxidation and histological changes in the kidneys were successfully prevented by the pre- administration of Vernonia amygdalina as evidenced by creatinine and urea and MDA level. These were made evident as the morphological scores across all experimental groups were significantly different from those of the positive control (group 2). Based on the current findings, it can be concluded that Vernonia amygdalina successfully minimizes the deleterious effects in kidney function and histological coherence associated with nephrotoxicity by strengthening the antioxidant defense system, suppressing oxidative stress, and mitigating apoptosis.

Store-operated Ca2+ channel signaling: Novel mechanism for podocyte injury in kidney disease.

Studies over the last decade have markedly broadened our understanding of store-operated Ca2+ channels (SOCs) and their roles in kidney diseases and podocyte dysfunction. Podocytes are terminally differentiated glomerular visceral epithelial cells which are tightly attached to the glomerular capillary basement membrane. Podocytes and their unique foot processes (pedicels) constitute the outer layer of the glomerular filtration membrane and the final barrier preventing filtration of albumin and other plasma proteins. Diabetic nephropathy and other renal diseases are associated with podocyte injury and proteinuria. Recent evidence demonstrates a pivotal role of store-operated Ca2+ entry (SOCE) in maintaining structural and functional integrity of podocytes. This article reviews the current knowledge of SOCE and its contributions to podocyte physiology. Recent studies of the contributions of SOC dysfunction to podocyte injury in both cell culture and animal models are discussed, including work in our laboratory. Several downstream signaling pathways mediating SOC function in podocytes also are examined. Understanding the pivotal roles of SOC in podocyte health and disease is essential, as SOCE-activated signaling pathways are potential treatment targets for podocyte injury-related kidney diseases.

Genetic nephrotic syndrome associated with disturbed function of glomerular slit membrane and podocyte cytoskeleton in children.

Genetic nephrotic syndrome is caused by pathogenic variants in genes encoding proteins necessary for the stability and functionality of the glomerular filtration barrier. To date, more than 70 genes associated with steroid-resistant nephrotic syndrome have been identified. We review the clinical and molecular aspects of genetic nephrotic syndrome with a particular focus on genes associated with slit membrane and podocyte cytoskeleton defects. Sanger sequencing and next-generation sequencing are widely used in the identification of novel gene variants and help us gain a better understanding of the disease. Despite these findings, therapy is mainly supportive and focused on the reduction of proteinuria and management of chronic kidney disease with an unfavorable outcome for a significant proportion of cases. Positive therapeutic effects of immunosuppressive drugs have been reported in some patients; however, their long-time administration cannot be generally recommended. Personalized treatment based on understanding the distinct disease pathogenesis is needed. With this, it will be possible to avoid harmful immunosuppressive therapy and improve outcomes and quality of life for pediatric patients suffering from genetic nephrotic syndrome.

Role of ion channels in the mechanism of proteinuria (Review).

Proteinuria is a common clinical manifestation of kidney diseases, such as glomerulonephritis, nephrotic syndrome, immunoglobulin A nephropathy and diabetic nephropathy. Therefore, proteinuria is considered to be a risk factor for renal dysfunction. Furthermore, proteinuria is also significantly associated with the progression of kidney diseases and increased mortality. Its occurrence is closely associated with damage to the structure of the glomerular filtration membrane. An impaired glomerular filtration membrane can affect the selective filtration function of the kidneys; therefore, several macromolecular substances, such as proteins, may pass through the filtration membrane and promote the manifestation of proteinuria. It has been reported that ion channels play a significant role in the mechanisms underlying proteinuria. Ion channel mutations or other dysfunctions have been implicated in several diseases, therefore ion channels could be used as major therapeutic targets. The mechanisms underlying the action of ion channels and ion transporters in proteinuria have been overlooked in the literature, despite their importance in identifying novel targets for treating proteinuria and delaying the progression of kidney diseases. The current review article focused on the four key ion channel groups, namely Na+, Ca2+, Cl- and K+ ion channels and the associated ion transporters.

A Project work on Recent approches in the Treatment of Diabetic Nepheropathy

Renal failure is a common long-torm complication of diabetes mellitus. Stages of diabetic nephropathy have been described that characterize its clinical course. Diabetic nephropathy develops secondary to long- changes that damage the glomeruli’s. Therapy that focuses on the control of glomerular pressures and systemic hypertension can slow the progression of proteinuria and deterioration of renal function. Angiotensin converting enzyme (ACE) inhibitors and calcium channel blockers have been demonstrated to be effective in the management of diabetic nephropathy. A systematic approach to the patient with diabetes with help identify those individuals early in the course of disease when proper therapy may be most helpful. Diabetic nephropathy is the leading cause of chronic renal disease and a major cause of cardiovascular mortality. Diabetic nephropathy has been categorized into stages: micro albuminuria and macro albuminuria. The cut-off values of micro- and macro albuminuria are arbitrary and their values have been questioned. Subjects in the upper-normal range of albuminuria seem to be at high risk of progression to micro- or macro albuminuria and they also had a higher blood pressure than normoalbuminuric subjects in the lower norm albuminuria range. Diabetic nephropathy screening is made by measuring albumin in spot urine. If abnormal, it should be confirmed in two out three samples collected in a three to six-months interval. Additionally, it is recommended that glomerular filtration rate be routinely estimated for appropriate screening of nephropathy, because some patients present a decreased glomerular filtration rate when urine albumin values are in the normal range. The two main risk factors for diabetic nephropathy are hyperglycemia and arterial hypertension, but the genetic susceptibility in both type 1 and type 2 diabetes is of great importance. Other risk factors are smoking, dyslipidemia, proteinuria, glomerular hyper filtration and dietary factors. Nephropathy is pathologically characterized in individuals with type 1 diabetes by thickening of glomerular and tubular basal membranes, with progressive meningeal expansion (diffuse or nodular) leading to progressive reduction of glomerular filtration surface. Concurrent interstitial morphological alterations and hyalinization of afferent and efferent glomerular arterioles also occur. Podocytes abnormalities also appear to be involved in the glomerulosclerosis process. In patients with type 2 diabetes, renal lesions are heterogeneous and more complex than in individuals with type 1 diabetes. Treatment of diabetic nephropathy is based on a multiple risk factor approach, and the goal is retarding the development or progression of the disease and to decrease the subject's increased risk of cardiovascular disease. Achieving the best metabolic control, treating hypertension (<130/80 mmHg) and dyslipidemia (LDL cholesterol <100 mg/dl), using drugs that block the renin-angiotensin-aldosterone system, are effective strategies for preventing the development of micro albuminuria, delaying the progression to more advanced stages of nephropathy and reducing cardiovascular mortality in patients with diabetes.

Renal Histologic Findings in Necropsies of Type 2 Diabetes Mellitus Patients

Background Very few studies have analyzed early histologic lesions of diabetic nephropathy (DN) in patients without signs of clinical involvement (microalbuminuria). In this study, we analyzed renal histologic lesions in necropsies of diabetic patients with or without previous signs of DN. Methods Histological material was analyzed from 21 autopsies of type 2 diabetes mellitus (T2DM) patients (9 with albuminuria and 12 without albuminuria) and 4 controls. Histologic lesions were evaluated according to the Tervaert classification. Results Kidneys of diabetic patients presented significantly higher scores in most histologic indices analyzed (glomerular basal membrane thickening, mild and severe mesangial expansion, nodular sclerosis, interstitial fibrosis, and tubular atrophy) than in nondiabetic controls (p < 0.01 in all cases). In contrast, no significant differences were detected between histologic scores when comparing the 21 diabetic patients with and without albuminuria. A significant percentage of cases without albuminuria showed moderate to severe histologic lesions, particularly severe mesangial expansion and severe glomerular vascular lesions. No significant differences were found in age, blood pressure, diabetes vintage, BMI, HbA1c, cholesterol, triglycerides, or treatments between the two (albuminuric vs. nonalbuminuric) T2DM patient groups. Conclusions Our data suggest that histologic lesions of DN are present in the early stages of the disease, even without albuminuria presence. More precise and earlier metabolic control is recommended in T2DM, and monitoring of risk factors can play a role in DN development.

Update on New Antigens in the Pathogenesis of Membranous Nephropathy

Previously, membranous nephropathies were divided into primary and secondary categories when the exact mechanism or pathogenetic factor were unknown. Approximately 70% accounted for primary membranous nephropathies. The remaining 30% were called secondary because they developed due to well-known diseases such as autoimmune diseases, tumours, infections, or drug assumptions. The discoveries of the M-type phospholipase A2 receptor and of thrombospondin type 1 domain containing 7A as causative antigens in a part of the so-called primary membranous nephropathies opened new knowledge on the effective causes of a large part of these diseases. The availability of novel techniques such as laser micro-dissection and tandem mass spectrometry, as well as immunochemistry with antibodies directed against novel proteins, allowed the confirmation of new antigens involved. The use of confocal microscopy and Western blot allowed detection of the new antigen on glomerular membrane, and the same antigen and relative antibodies have been detected in serum samples. Through these techniques, four new antigens were first detected, including neural epidermal growth factor 1 and semaphorin 3B in the so-called primary membranous nephropathy, and exostosin 1 and 2 and neural cell adhesion molecule 1 in lupus membranous nephropathy. The aim of this study is to describe the characteristics of the new antigens discovered and their association with other diseases. In addition, new antigens are on the horizon, and the story of primary membranous nephropathy is still to be completely written and understood.

Leishmania (L.) infantum BH401 strain induces classic renal lesions in dogs: Histological and confocal microscopy study

Extracellular matrix (ECM) alterations in visceral leishmaniasis are related mainly to collagen deposition (fibropoiesis). In canine visceral leishmaniasis (CVL), an intense fibrosis associated to chronic inflammation in organs such as kidneys is described. However, renal fibropoiesis has not been described in natural or experimental infections with L. (L.) infantum. We aimed to characterize renal nephropathies by histology and confocal microscopy comparing renal lesions in dogs naturally and experimentally infected with L. (L.) infantum. Sixty-two mixed-breed symptomatic dogs naturally infected with L. (L.) infantum, sixteen beagles experimentally infected with two strains of L. infantum (eleven dogs with the BH400 strain and five dogs with the BH401 strain), and five uninfected beagles (controls) were used. Samples were stained with hematoxylin & eosin for routine histology. Congo red was used to visualize amyloid protein deposits, periodic acid-Schiff to identify glomerular basal membrane anomalies, Masson's trichrome for collagen deposits, and Jones' methenamine silver to reveal membranous glomerulonephropathy. Immunohistochemistry was used to identify Leishmania amastigotes, and confocal microscopy was used for macrophage characterization (L1/calprotectin and CD163 antigen receptors). The most common lesions were chronic glomerular and interstitial nephritis, which was found in all naturally infected dogs and dogs experimentally infected with L. infantum strain BH401 but not with the BH400 strain. Glomeruloesclerosis was the main lesion presented in all BH401 group. Morphometric analysis revealed positive correlation of renal glomeruli tufts with cellular expression of L1/calprotectin and CD163 antigens. Leishmania infantum strain BH401 shows pathogenicity that may be sufficient to induce classic chronic visceral renal leishmaniasis.

New antigens involved in membranous nephropathy beyond phospholipase A2 receptor.

When the physiopathology of membranous nephropathy was first described, almost 30% of cases were recognized to be secondary to well-known diseases such as autoimmune diseases, tumors or infections. The remaining 70% cases were called primary membranous nephropathy as the exact mechanism or pathogenic factor involved was unknown. The discovery of the M type phospholipase A2 receptor and thrombospondin type 1 domain containing 7A as causative antigens in these “so called” primary membranous nephropathies provided new insights into the effective causes of a large proportion of these cases. Novel techniques such as laser microdissection and tandem mass spectrometry as well as immunochemistry with antibodies directed against novel proteins allowed the confirmation of new involved antigens. Finally, using confocal microscopy to localize these new antigens and immunoglobulin G and Western blot analysis of serum samples, these new antigens were detected on the glomerular membrane, and the related antibodies were detected in serum samples. The same antigens have been recognized in some cases of secondary membranous disease due to autoimmune diseases, tumors and infections. This has allowed examination of the relationship between antigens in primary membranous nephropathy and their presence in some secondary nephropathies. The aim of this study is to describe the characteristics of the new antigens discovered and their association with other diseases.

Sirtuin Family and Diabetic Kidney Disease.

Diabetes mellitus (DM) is gradually attacking the health and life of people all over the world. Diabetic kidney disease (DKD) is one of the most common chronic microvascular complications of DM, whose mechanism is complex and still lacks research. Sirtuin family is a class III histone deacetylase with highly conserved NAD+ binding domain and catalytic functional domain, while different N-terminal and C-terminal structures enable them to bind different deacetylated substrates to participate in the cellular NAD+ metabolism. The kidney is an organ rich in NAD+ and database exploration of literature shows that the Sirtuin family has different expression localization in renal, cellular, and subcellular structures. With the progress of modern technology, a variety of animal models and reagents for the Sirtuin family and DKD emerged. Machine learning in the literature shows that the Sirtuin family can regulate pathophysiological injury mainly in the glomerular filtration membrane, renal tubular absorption, and immune inflammation through various mechanisms such as epigenetics, multiple signaling pathways, and mitochondrial function. These mechanisms are the key nodes participating in DKD. Thus, it is of great significance for target therapy to study biological functions of the Sirtuin family and DKD regulation mechanism in-depth.

Two novel variants in the lecithin:cholesterol acyltransferase gene resulted in classic LCAT deficiency

Background and aimsWe report the first two cases of familial lecithin:cholesterol acyltransferase (LCAT) deficiency in Croatia with classical clinical and biochemical features. Patients and methodsA 30-year-old man with nephrotic syndrome, corneal opacities, hepatosplenomegaly, anemia, low high-density lipoprotein (HDL)-cholesterol levels and arterial hypertension (blood pressure >200/100 mmHg) was admitted to our department. At admission, he had an elevated creatinine serum level (233 μmol/L), proteinuria of 12 g in 24-h urine (g/24 h), 3–7 erythrocytes in urine sediment and notable anemia (hemoglobin level 90 g/l). His HDL-cholesterol was significantly low (0.42 mmol/L). Besides chronic kidney disease (CKD), other secondary causes of hypertension were ruled out. The patient was previously diagnosed with membranous nephropathy and treated unsuccessfully with immunosuppressive agents (steroids, cyclosporine, cyclophosphamide). Re-evaluation of histopathological findings of kidney biopsy revealed massive deposition of lipid material in the glomerular basal membrane and in the mesangial region. His 4-year younger brother was also evaluated due to corneal opacities and new-onset arterial hypertension. Nephrotic range proteinuria with preserved global renal function was determined. He also had very low HDL-cholesterol levels. ResultsKidney biopsies from both patients were consistent with LCAT deficiency. The disease was confirmed by measurement of LCAT enzyme activity, plasma cholesterol esterification rate, and genetic testing. Two novel missense variants in the LCAT gene (c.496G > A and c.1138T > C) were found. ConclusionsTo our knowledge, the presented cases are the first reported cases of genetic LCAT deficiency in Croatia. Given the clinical presentation, the complete lack of LCAT activity and cholesterol esterification rate, diagnosis of familial LCAT deficiency was made.

The Level of Plasma Cystatin C in Patients with Chronic Kidney Disease

Background: Chronic kidney disease (CKD) is an increasingly common disease worldwide and has become a global health problem, especially in Vietnam. Cystatin C is a marker for the detection, classification, and prognosis of CKD. Cystatin C is filtered entirely through the glomerular membrane, reabsorbed, and metabolized completely in the renal tubules. In case of damage to the kidneys, glomerular filtration rate declines, and some substances increase in the blood, such as cystatin C. The concentration of cystatin C changes with damage to the renal system. Objectives: This study aimed to estimate the concentration of cystatin C and its variation in the different stages of CKD. Methods: A descriptive, cross-sectional study was conducted on 40 healthy individuals and 137 patients with CKD grade III, IV, and V in 103 Hospital. The concentration of cystatin C was estimated in all subjects. Results: Cystatin C plasma levels were significantly higher in the CKD group (9.17 ± 3.75 mg/L) than in the control group (0.82 ± 0.12 mg/L). Cystatin C plasma levels increased linearly with the serious kidney failure as the stage of CKD. Conclusions: Cystatin C is an effective marker for estimating kidney damage in CKD.

MO611: Glycated Albumin Levels Predict The Type of Kidney Damage in Diabetic Patients

Abstract BACKGROUND AND AIMS Diabetes mellitus remains the most frequent cause of end-stage renal disease (ESRD) in developing countries. The main determinant of the onset of nephropathy in diabetes is hyperglycemia which brings to glycation of albumin and haemoglobin with higher concentration of AGEs (advanced glycation end products), finally leading to fibrosis, inflammation and albuminuria. Glycated albumin (GA) was introduced as an alternative to hemoglobin A1c (HbA1c) for glycemic control in the CKD population, with some advantages for diabetic patients with diabetic kidney disease (DKD), since it is not influenced by anemia and associated treatments and it is not affected by serum albumin levels. Although some evidences in literature demonstrated that GA is superior to HbA1c in assessing blood glucose control in DKD (Gan T et al. J Diabetes Complications. 2018); however, KDIGO Guidelines still recommend HbA1c, although underlying some limitations in the context of DKD, meaning that new markers are needed in order to monitor this class of diabetic patients. Kidney disease in diabetic patients can include different kind of renal damage ranging from real diabetic nephropathy (DN, with Kimmelstiel–Wilson lesions, glomerular basal membrane thickening, proliferation of mesangial matrix) to nondiabetic renal disease (NDRD), in the presence or absence of real DN, thus influencing prognosis and treatment. The purpose of the study was to evaluate the clinical utility of the GA dosage, alone or with other molecular and clinical markers as noninvasive biomarkers for the prediction of the progression and type of kidney damage in the diabetic patient. METHOD We enrolled 108 diabetic patients in follow-up at our center, 90 with a biopsy-proven diagnosis of kidney disease and 18 with no kidney dysfunction. Among the 90 patients, 51 had real diabetic nephropathy (DN) or mixed forms (DN + NDRD) and 39 had non-diabetic renal disease (NDRD). GA dosage was obtained by QuantILab® Glycated Albumin assay (Instrumentation Laboratory SpA, Milan, Italy). qPCR was used to evaluate urinary levels of miR27b-3p, a biomarker that predicts the kind of renal damage in diabetic patients and is related to kidney fibrosis (Conserva F et al. Sci Rep. 2019). Statistical analysis was performed using ‘SPSS Statistical Software.’ RESULTS We observed that GA values had a significantly different distribution among DN, NDRD and diabetic patients without renal dysfunction (P = 0.003); conversely, there was no statistical difference in HbA1c distribution although a trend was visible. In the entire cohort, only GA levels, but not HbA1c levels, were significantly correlated with fasting glucose (P = 0.001) and the duration of diabetes (P = .001). In the single classes, only in DN patients there was a significant correlation between GA and diabetes duration (P = .02) and GA and HbA1c (P = 0.01) but not in the NDRD class (P = 0.43). We then applied a multivariate logistic regression model to discriminate real DN and NDRD. We demonstrated that GA is the only significant predictor of real DN in a model corrected for sex, age and serum creatinine {P = 0.009; OR = 0.757–0.962; [95% confidence interval (CI)]}, whereas the same logistic regression model with HbA1c demonstrated no significance (P = 0.082). In the same cohort, we also evaluated miR-27b-3p expression levels, whose levels are correlated with renal fibrosis in DN, and we observed that there was a significant and direct correlation also with GA levels (P = 0.001), thus suggesting the possibility to integrate these biomarkers to predict the kind of renal damage in diabetic patients. CONCLUSION Our study described for the first time the role played by GA as a diagnostic marker in the identification of the different kind of renal damage in diabetic patients. All these evidences support the need to introduce GA as an index of glycemic control to be associated with other molecular markers, such as miRNAs, in order to noninvasively diagnose the kind of renal damage in diabetic patients.

MO616: The Genetic Background Predicts The Kind of Renal Damage and Fibrosis Progression in Diabetic Patients

Abstract BACKGROUND AND AIMS Diabetic Nephropathy (DN) is the major causes of end-stage renal failure. DN diagnosis is based on typical histological features (Kimmelstiel–Wilson lesions, glomerular basal membrane thickening and proliferation of mesangial matrix). Not all diabetic patients with kidney disease develop true DN: kidney impairment can be due to a nondiabetic renal disease (NDRD) in the presence or absence of real DN. Thus, there is the need for noninvasive biomarkers, related to specific pathogenic processes, to discriminate DN and NDRD, and/or to predict DN onset. In the case of DN, there is extensive evidence in literature of genetic contribution to disease susceptibility and lots of efforts aim at the identification of specific loci. The research group demonstrated that a characteristic feature of DN is an increase in Lys63-ubiquitinated proteins at tubular level that leads to epithelial-to-mesenchymal transition (EMT) and finally to the progression of the tubular-interstitial fibrosis and the renal damage in DN patients (Pontrelli P et al. FASEB J 2017). Ube2V1 is the unique E2 enzyme known for producing Lys63-linked ubiquitin chains. Moreover, two miRNAs (miR27b-3p e miR1228-3p), which interact specifically with Ube2V1 transcript, predict the type of renal damage in diabetic patients and are related with kidney fibrosis (Conserva F et al. Sci Rep 2019). The goal of this project was to identify single nucleotide polymorphisms (SNPs) able to predict the different kind of renal damage and the progression of kidney disease in diabetic patients. METHOD We selected by UCSC genome, 10 HapMap SNPs of patients within coding and regulatory sequences both of miR27b-3p and miR1228-3p and Ube2V1 gene in order to evaluate their diagnostic and prognostic potential. The patients enrolled in this study were diabetic patients with a biopsy-proven DN diagnosis (DN), diabetic patients with a biopsy-proven diagnosis of other nephropathy than DN (NDRD), diabetic patients without clinical signs of impaired renal function (T2D), diabetic patients with a biopsy-proven coexistence of both conditions (ND + NDRD), non-diabetic patients with glomerulonephritis (CKD), non-diabetic patients without renal damage (CTRL). The DNA of 201 subjects (patients and controls) was isolated from blood samples, and 10 HapMap SNPs (rs3802456, rs4744422, rs10761364, rs7853195 in the control region of miR27b-3p; rs2306692, rs4759277, rs4759044, rs17547610, rs4759275 in the control region of miR1228-3p; rs761214 in the UBE2v1 gene) for each patient were analyzed using TaqMan real-time PCR. Glomerular and tubulointerstitial fibrosis in kidney biopsies was quantified on Sirius Red staining using the Aperio Imagescope software. RESULTS The analyzed SNPs showed a different genotype frequency among all the patients’ classes. Interestingly, SNPs rs4759275, rs4759277, rs4744422 and rs3802456 showed a statistically significant difference in genotype frequency comparing DN patients with CEU Population (Northern and Western European Ancestry in Utah) (P &amp;lt; 0.04, 0.05, 0.002, 0.001, respectively) and a control cohort enclosing CTRL and T2D (P &amp;lt; 0.02, 0.05, 0.001 and 0.04, respectively). SNPs rs761214, rs10761364 and rs2306692 genotypes frequency was statistically different among DN patients and the control cohort (P &amp;lt; 0.001). The genotype frequencies of the SNPs rs10761364 (P &amp;lt; 0.01) and rs7853195 (P &amp;lt; 0.04) resulted significantly related to tubular fibrosis in DN patients, while the SNPs rs4744422 (P &amp;lt; 0.03) and rs761214 (P &amp;lt; 0.02) to the glomerular one. In order to evaluate the diagnostic power of the identified SNPs, we used a logistic regression model, and we observed that the SNP rs10761364, adjusted for age, sex, eGFR and glycaemic index, discriminate DN from NDRD {P &amp;lt; 0.05; OR = 1.002–1.008; [95% confidence interval (CI)]}. CONCLUSION Our data demonstrated that the allelic forms of the analyzed SNPs are related to the different kind of renal damage in diabetic patients. Their prognostic and diagnostic potential could represent the starting point to create a new noninvasive diagnosis system based on clinical and genotyping data.

Review of Knowledge of Uranium-Induced Kidney Toxicity for the Development of an Adverse Outcome Pathway to Renal Impairment

An adverse outcome pathway (AOP) is a conceptual construct of causally and sequentially linked events, which occur during exposure to stressors, with an adverse outcome relevant to risk assessment. The development of an AOP is a means of identifying knowledge gaps in order to prioritize research assessing the health risks associated with exposure to physical or chemical stressors. In this paper, a review of knowledge was proposed, examining experimental and epidemiological data, in order to identify relevant key events and potential key event relationships in an AOP for renal impairment, relevant to stressors such as uranium (U). Other stressors may promote similar pathways, and this review is a necessary step to compare and combine knowledge reported for nephrotoxicants. U metal ions are filtered through the glomerular membrane of the kidneys, then concentrate in the cortical and juxtaglomerular areas, and bind to the brush border membrane of the proximal convoluted tubules. U uptake by epithelial cells occurs through endocytosis and the sodium-dependent phosphate co-transporter (NaPi-IIa). The identified key events start with the inhibition of the mitochondria electron transfer chain and the collapse of mitochondrial membrane potential, due to cytochrome b5/cytochrome c disruption. In the nucleus, U directly interacts with negatively charged DNA phosphate, thereby inducing an adduct formation, and possibly DNA strand breaks or cross-links. U also compromises DNA repair by inhibiting zing finger proteins. Thereafter, U triggers the Nrf2, NF-κB, or endoplasmic reticulum stress pathways. The resulting cellular key events include oxidative stress, DNA strand breaks and chromosomal aberrations, apoptosis, and pro-inflammatory effects. Finally, the main adverse outcome is tubular damage of the S2 and S3 segments of the kidneys, leading to tubular cell death, and then kidney failure. The attribution of renal carcinogenesis due to U is controversial, and specific experimental or epidemiological studies must be conducted. A tentative construction of an AOP for uranium-induced kidney toxicity and failure was proposed.

IDF21-0124 Relationship between Serum Zinc Status and Diabetic Nephropathy in Algerian Patients with Type 2 Diabetes

Background: Diabetic nephropathy is a microvascular complication associated with diabetes that causes the kidneys to slowly deteriorate, leading to end-stage renal disease. Nephropathy associated with diabetes has been attributed to oxidative stress. Chronic zinc deficiency generally results in an increased sensitivity to the effects of oxidative stress. Zinc deficiency is often seen in diabetic patients. This alteration in zinc status appears to be involved in the development of microvascular complications of diabetes. Aim: The objective of this study will be to explore the relationship between zinc status and the progression of nephropathy in type 2 diabetes. Method: The study involved 80 normotensive diabetic patients with positive microalbuminuria and 60 healthy non-diabetic subjects of corresponding age. For all subjects, a serum zinc assay was performed on the ICE 3300 atomic absorption spectrometer from Thermo Fisher, a serum creatinine assay on Cobas 501 from Roche Diagnostic with evaluation of GFR, as well as a microalbuminuria assay. on the DCA Vantage from Siemens. Results: Serum zinc levels were low (p <0.001) in diabetic patients compared to non-diabetic control subjects. Elevated levels of microalbuminuria (p <0.001) were observed in diabetic patients with low serum zinc levels compared to those with normal serum zinc levels. Serum zinc level in diabetic patients was inversely correlated with serum creatinine (r = −0.51, p <0.001), microalbuminuria (r = −0.587, p <0.001) and positively with GFR (r = 0.24, p <0.01). Discussion: The results of our study support the observation that diabetes affects zinc status with a significant decrease in serum zinc levels at the onset of diabetic complications. During progression to the stages of diabetic nephropathy, morphological and structural changes occur in the glomerular and basal membrane of the kidneys, hyperfiltration, thickening of the glomerular basement membrane. All of these changes will cause albumin with trace metals to leak into the urine. Therefore, the hypozincemia seen in diabetics can be attributed to hyperzincuria. The results of this study are consistent with results reported by others.

Chronic intermittent hypoxia induces the pyroptosis of renal tubular epithelial cells by activating the NLRP3 inflammasome

ABSTRACT Obstructive sleep apnea syndrome (OSAS) is a respiratory disorder and chronic intermittent hypoxia (CIH) is an important pathological characteristic of OSAS. Injuries on renal tubular epithelial cells were observed under the condition of CIH. Pyroptosis is a programmed mode of cell death following cell apoptosis and cell necrosis, which is mediated by NLRP3 signaling. The present study aims to investigate the effects of CIH on the pyroptosis of renal tubular epithelial cells and the underlying mechanism. Firstly, CIH was induced in two renal tubular epithelial cell lines, HK-2 cells and TCMK-1 cells. As the aggravation of hypoxia, an increasing trend of elevated apoptotic rate was observed in HK-2 cells and TCMK-1 cells, accompanied by the excessive release of ROS and LDH, and upregulation of NLRP3. Subsequently, the CIH model was established on rats. The pathological analysis results indicated that in CIH rats, the glomerular bottom membrane and mesangium were slightly thickened and edema was observed in the renal tubule epithelium. More serious injury was observed in the moderate intermittent hypoxia group. The expression level of IL-1β and IL-18 was promoted as the aggravation of hypoxia, accompanied by the elevated production of LDH and ROS. The expression level of cleaved Caspase-1, Caspase-1, GSDMD, TLR4, MyD88, NF-κB, p-NF-κB, and NLRP3 was found significantly upregulated as the aggravation of hypoxia. Lastly, the pathological changes in rats induced by CIH were dramatically abolished by MCC950, a specific inhibitor of NLRP3. Collectively, CIH triggered the pyroptosis of renal tubular epithelial cells by activating the NLRP3 inflammasome.

A comprehensive insight into autophagy and its potential signaling pathways as a therapeutic target in podocyte injury.

As part of the glomerular filtration membrane, podocyte is terminally differentiated, structurally unique, and highly specialized in maintaining kidney function. Proteinuria caused by podocyte injury (foot process effacement) is the clinical symptom of various kidney diseases (CKD), including nephrotic syndrome. Podocyte autophagy has become a powerful therapeutic strategy target in ameliorating podocyte injury. Autophagy is known to be associated significantly with sirtuin-1, proteinuria, and podocyte injury. Various key findings in podocyte autophagy were reported in the past ten years, such as the role of endoplasmic reticulum (ER) stress in podocyte autophagy impairment, podocyte autophagy-related gene, essential roles of the signaling pathways: Mammalian Target of Rapamycin (mTOR)/ Phosphoinositide 3-kinase (PI3k)/ serine/threonine kinase 1 (Akt) in podocyte autophagy. These significant factors caused podocyte injury associated with autophagy impairment. Sirtuin-1 was reported to have a vital key role in mTOR signaling, 5'AMP-activated protein kinase (AMPK) regulation, autophagy activation, and various critical pathways associated with podocyte's function and health; it has potential value to podocyte injury pathogenesis investigation. From these findings, podocyte autophagy has become an attractive therapeutic strategy to ameliorate podocyte injury, and this review will provide an in-depth review on therapeutic targets he podocyte autophagy.

Podocytes – potential biomarker for early diagnosis of pre-eclampsia

Pre-eclampsia is a medical complication in pregnancy that occurs in about 5% of pregnant women, after the 20th week of gestation. This complication causes serious health effects on pregnant women, even death in both those women and their fetuses. Pre-eclampsia patients are characterized by gestational hypertension associated with proteinuria and histological evidence of glomerular injury. Many reports suggested certain biomarkers of pre-eclampsia, including a decreased VEGF (Vascular Epithelial Growth Factor) level or an increased sFlt-1 (VEGF receptor) level in serum, which is related to an increase in the risk of this issue. Pre-eclampsia might be associated with an increased risk of several kidney diseases for many years following diagnosis with this issue. Evidence showed that women with a history of pre-eclampsia might have a higher risk of kidney diseases such as end-stage renal disease (ESRD) and focal segmental glomerulosclerosis (FSGS) than women with healthy pregnancies. Other studies showed that podocytes might be involved in glomerular lesions in pre-eclampsia patients. Podocytes are specialized epithelial cells located on the surface of the glomerular capillary, which is part of the glomerular filter membrane along with the endothelial cells and the glomerular basement membrane. Podocytes have a responsibility to ensure the glomerular membrane’s selective permeability. Some methods recently are being developed to detect the podocytes in urine samples such as immunohistochemistry, Reverse Transcriptase Polymerase Chain Reaction (RT – PCR), suggesting the potential application of those cells as biomarkers in the early diagnosis of pre-eclampsia. This review summarized the evidence about the role of podocytes in the pathological mechanism of pre-eclampsia, the risk of chronic kidney diseases as well as the potential predictive value of podocytes in the early diagnosis of pre-eclampsia.

Synergistic effects of sinapic acid and ellagic acid ameliorate streptozotocin-induced diabetic nephropathy by inhibiting apoptosis, DNA damage, and structural deterioration in rats.

Diabetic nephropathy (DN), a global problem that threatens human health, is an important reason for chronic kidney disease and kidney failure. In our study, it was aimed to investigate the individual and combined effects of SA and EA in streptozotocin (STZ)-induced rats. The groups are as follows: Control, untreated diabetic, diabetic treated with Sinapic acid (SA), diabetic treated with Ellagic acid (EA), diabetic treated with SA and EA, treated with SA, treated with EA, and treated with SA and EA. Total kidney volume, total glomerulus volume, total filtration space volume, caspase-3, and 8-OHdG immunoreactivity, Malondialdehyde (MDA), Glutathione (GSH), Catalase (CAT), serum urea, and creatinine levels were evaluated by stereological, immunohistochemical, and biochemical methods. The findings of the study showed that total kidney volume, total glomerulus volume, total filtration gap volume, caspase-3, and 8-OHdG immunoreactivity, MDA, serum urea, and creatinine levels significantly increased in the untreated diabetic group compared to the control group. Also, severe mesangial and glomerular enlargement, extracellular matrix accumulation, and glomerular and tubular basal membrane thickness were observed in the tubulointerstitial and glomerular of the diabetic rats. However, individual and combined treatments of SA and EA ameliorated these histological changes. Additionally, decreased GSH and CAT in the untreated diabetic group increased by SA and EA treatment. The findings suggest that treatment of SA and EA prevent apoptosis and DNA damage and structural changes in STZ-induced DN. However, the combined treatment of SA and EA were more effective than their individual treatments in all parameters except serum urea and creatinine.