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Persistent albuminuria (PA) is common in sickle cell anaemia (SCA). With the association of chronic kidney disease (CKD) with increased mortality, biomarkers that predict its development or progression are needed. We evaluated the association of select biomarkers with PA in adults with SCA using Kruskal-Wallis rank-sum test and logistic regression models, with adjustment for multiple testing. Of 280 subjects, 100 (35.7%) had PA. Median plasma levels of soluble vascular cell adhesion molecule-1 (VCAM-1) (1176.3 vs. 953.4 ng/mL, false discovery rate [FDR] q-value <0.003), thrombin-antithrombin complex (5.5 vs. 4.7 ng/mL, FDR q-value = 0.04), and urinary angiotensinogen (AGT) (12.2 vs. 5.3 ng/mg, FDR q-value <0.003), urinary nephrin (30.6 vs. 27.2 ng/mg, FDR q-value = 0.04), and urinary kidney injury molecule-1 (KIM-1) (0.8 vs. 0.5 ng/mg, FDR q-value <0.003), normalized to urine creatinine, were significantly higher in subjects with PA. In multivariable analysis, only urinary AGT (odds ratio = 1.058, FDR q-value <0.0001) remained a significant predictor of PA. In addition, soluble VCAM-1 (FDR q-value <0.0001), D-dimer (FDR q-value <0.0001), urinary AGT (FDR q-value <0.0001), KIM-1 (FDR q-value <0.0001), and nephrin (FDR q-value <0.0001) were significantly associated with urine albumin-creatinine ratio in multivariable analyses. Longitudinal studies to evaluate the predictive capacity of biomarkers for the development and progression of CKD in SCA are warranted.
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Background Human nephrin (hNeph) (podocyte protein) has been known to be involved in both the formation and maintenance of the slit diaphragm (SD) and also acts as a hub protein in the podocyte by modulating cell polarity, cell survival, cell adhesion, cytoskeletal organization, mechano-sensing, and SD turn-over. Methodology In the present investigation, we aimed to analyse the hNeph and mouse nephrin (mNeph) and their interactions with 13 proteins using the molecular docking method. The 13 selected human proteins which include matrix metalloproteinases (MMP 2 and 9), retinol-binding proteins (RBP 3 and 4), kallikrein 1 (KLK 1), uromodulin, insulin-like growth factor binding protein 7 (IGFBP7), cystatin C, podocin, beta arrestin 1, vang-like protein 2 (VANGL2), dynamin 1, and tensin-like C1 domain-containing phosphatase (TENC1) were studied on the docking analysis of hNeph and mNeph by using the HDOCK (protein-protein) docking method. In addition, the physicochemical (PC) properties of 15 proteins were performed using the ProtParam web server. Results In the present investigation, five chosen human proteins, namely, IGFBP7, cystatin C, podocin, VANGL2, and TENC1, have exhibited theoretical isoelectric point (PI) values greater than 7.0. The protein-protein docking analysis has shown that hKLK and hVANGL2 exhibited the maximum docking score of -206.39 kcal/mol and -329.28 (kcal/mol) with the target proteins mNeph and hNeph, respectively. Conclusions Thus, the current finding highlights the interactions of hNeph and mNeph with 13 chosen proteins, which may help in renal disease management.
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The phosphorylation of the transmembrane protein nephrin has been shown to play an important role in signaling in kidney podocytes, and it has now been shown to also play a key role in regulating pancreatic ß-cell function. Williamson et al have recently shown that the loss of nephrin tyrosine phosphorylation on its 3 cytoplasmic YDxV motifs can enhance insulin release in aged female mice. These studies suggest that blocking nephrin phosphorylation may be an effective treatment option for improving ß-cell function.
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Células Secretoras de Insulina , Proteínas de la Membrana , Animales , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/efectos de los fármacos , Proteínas de la Membrana/metabolismo , Fosforilación/efectos de los fármacos , Ratones , Femenino , Humanos , Insulina/metabolismo , Podocitos/metabolismo , Podocitos/efectos de los fármacosRESUMEN
Albuminuria is characterized by a disruption of the glomerular filtration barrier, which is composed of the fenestrated endothelium, the glomerular basement membrane, and the slit diaphragm. Nephrin is a major component of the slit diaphragm. Apart from hemodynamic effects, Ang II enhances albuminuria by ß-Arrestin2-mediated nephrin endocytosis. Blocking the AT1 receptor with candesartan and irbesartan reduces the Ang II-mediated nephrin-ß-Arrestin2 interaction. The inhibition of MAPK ERK 1/2 blocks Ang II-enhanced nephrin-ß-Arrestin2 binding. ERK 1/2 signaling, which follows AT1 receptor activation, is mediated by G-protein signaling, EGFR transactivation, and ß-Arrestin2 recruitment. A mutant AT1 receptor defective in EGFR transactivation and ß-Arrestin2 recruitment reduces the Ang II-mediated increase in nephrin ß-Arrestin2 binding. The mutation of ß-Arrestin2K11,K12, critical for AT1 receptor binding, completely abrogates the interaction with nephrin, independent of Ang II stimulation. ß-Arrestin2K11R,K12R does not influence nephrin cell surface expression. The data presented here deepen our molecular understanding of a blood-pressure-independent molecular mechanism of AT-1 receptor blockers (ARBs) in reducing albuminuria.
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Angiotensina II , Endocitosis , Proteínas de la Membrana , Receptor de Angiotensina Tipo 1 , Endocitosis/efectos de los fármacos , Endocitosis/fisiología , Animales , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Angiotensina II/farmacología , Angiotensina II/metabolismo , Humanos , Receptor de Angiotensina Tipo 1/metabolismo , Receptor de Angiotensina Tipo 1/genética , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Bloqueadores del Receptor Tipo 1 de Angiotensina II/farmacología , Ratones , Albuminuria/metabolismo , Podocitos/metabolismo , Podocitos/efectos de los fármacos , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/genética , Compuestos de Bifenilo/farmacología , Irbesartán/farmacología , Células HEK293 , Arrestina beta 2/metabolismo , Arrestina beta 2/genética , Bencimidazoles , TetrazolesRESUMEN
BACKGROUND: Steroid-resistant nephrotic syndrome (SRNS) is the second most frequent cause of chronic kidney disease in children and young adults. The most severe form of steroid-resistant nephrotic syndrome is congenital nephrotic syndrome Finnish type (CNSF), caused by biallelic loss-of-function variants in NPHS1, encoding nephrin. Since each of the 68 monogenic causes of steroid-resistant nephrotic syndrome represents a rare cause of the disease, tailoring therapeutic interventions to multiple molecular targets remains challenging, suggesting gene replacement therapy (GRT) as a viable alternative. To set the ground for a gene replacement study in vivo, we established rigorous, quantifiable, and reproducible phenotypic assessment of a conditional Nphs1 knockout mouse model. METHODS: By breeding a floxed Nphs1fl/- mouse (Nphs1tm1Afrn/J) previously studied for pancreatic ß-cell survival with a podocin promoter-driven Cre recombinase mouse model (Tg(NPHS2-Cre)295Lbh/J), we generated mice with podocyte-specific nephrin deficiency (Nphs1fl/fl NPHS2-Cre +). RESULTS: We observed a median survival to postnatal day P5 in nephrin-deficient mice, whereas heterozygous control mice and wild type (WT) control group showed 90% and 100% survival, respectively (at P50 days). Light microscopy analysis showed a significantly higher number of renal-tubular microcysts per kidney section in nephrin-deficient mice compared to the control groups (P < 0.0022). Transmission electron microscopy demonstrated reduced foot process (FP) density in nephrin-deficient mice compared to controls (P < 0.0001). Additionally, proteinuria quantitation using urine albumin-to-creatinine ratio (UACR) was significantly higher in nephrin-deficient mice compared to controls. CONCLUSIONS: This study represents the first comprehensive description of the kidney phenotype in a nephrin-deficient mouse model, laying the foundation for future gene replacement therapy endeavors.
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BACKGROUND: Nephrin is a transmembrane protein with well-established signaling roles in kidney podocytes, and a smaller set of secretory functions in pancreatic ß cells are implicated in diabetes. Nephrin signaling is mediated in part through its 3 cytoplasmic YDxV motifs, which can be tyrosine phosphorylated by high glucose and ß cell injuries. Although in vitro studies demonstrate these phosphorylated motifs can regulate ß cell vesicle trafficking and insulin release, in vivo evidence of their role in this cell type remains to be determined. METHODS: To further explore the role of nephrin YDxV phosphorylation in ß cells, we used a mouse line with tyrosine to phenylalanine substitutions at each YDxV motif (nephrin-Y3F) to inhibit phosphorylation. We assessed islet function via primary islet glucose-stimulated insulin secretion assays and oral glucose tolerance tests. RESULTS: Nephrin-Y3F mice successfully developed pancreatic endocrine and exocrine tissues with minimal structural differences. Unexpectedly, male and female nephrin-Y3F mice showed elevated insulin secretion, with a stronger increase observed in male mice. At 8 months of age, no differences in glucose tolerance were observed between wild-type (WT) and nephrin-Y3F mice. However, aged nephrin-Y3F mice (16 months of age) demonstrated more rapid glucose clearance compared to WT controls. CONCLUSION: Taken together, loss of nephrin YDxV phosphorylation does not alter baseline islet function. Instead, our data suggest a mechanism linking impaired nephrin YDxV phosphorylation to improved islet secretory ability with age. Targeting nephrin phosphorylation could provide novel therapeutic opportunities to improve ß cell function.
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Prueba de Tolerancia a la Glucosa , Secreción de Insulina , Células Secretoras de Insulina , Insulina , Proteínas de la Membrana , Animales , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética , Fosforilación , Ratones , Masculino , Secreción de Insulina/fisiología , Células Secretoras de Insulina/metabolismo , Femenino , Insulina/metabolismo , Tirosina/metabolismo , Envejecimiento/metabolismo , Intolerancia a la Glucosa/metabolismo , Ratones Endogámicos C57BL , Glucosa/metabolismoRESUMEN
Background/Objectives: Glomerulopathy is a term used to describe a broad spectrum of renal diseases, characterized by dysfunction of glomerular filtration barrier, especially of podocytes. Several podocyte-associated proteins have been found and proved their usefulness as urine markers of podocyte dysfunction. Two of them are nephrin (NEP) and prodocalyxin (PDC). This study aims to evaluate the association of podocyte damage, as it is demonstrated via the concentrations of urinary proteins, with clinical and histological data from patients with several types of glomerulonephritis. Methods: We measured urine levels of two podocyte-specific markers, NEP and PDC (corrected for urine creatinine levels), in patients with a wide range of glomerulopathies. Serum and urine parameters as well as histological parameters from renal biopsy were recorded. Results: In total, data from 37 patients with glomerulonephritis and 5 healthy controls were analyzed. PDC and NEP concentrations correlated between them and with serum creatinine levels (p = 0.001 and p = 0.013 respectively), and with histological lesions associated with chronicity index of renal cortex, such as severe interstitial fibrosis, severe tubular atrophy and hyalinosis (for PDC/NEP, all p < 0.05). In addition, the PDC and NEP demonstrated statistically significant correlations with interstitial inflammation (p = 0.018/p = 0.028). Regarding electron microscopy evaluation, PDC levels were correlated with distinct characteristics, such as fibrils and global podocyte foot process fusion, whereas the NEP/CR ratio was uniquely significantly associated with podocyte fusion only in non-immune-complex-mediated glomerulonephritis (p = 0.02). Among the other clinical and histological parameters included in our study, a strong correlation between proteinuria >3 g/24 h and diffuse fusion of podocyte foot processes (p = 0.016) was identified. Conclusions: Podocalyxin and nephrin concentrations in urine are markers of podocyte dysfunction, and in our study, they were associated both with serum creatinine and histological chronicity indices.
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Background: Diabetic kidney disease (DKD) is the most common and deranging microvascular complication of diabetes mellitus (DM). Podocytopathy is a key component of glomerular damage in DKD. Micro RNA-21 (miRNA-21) is an epigenetic regulator that plays a role in podocyte damage; however, the results of previous studies have not resolved the controversy about the role of miRNA-21 in the pathogenesis of DKD. Objective: The objective was to investigate the correlation between miRNA-21 levels and urinary nephrin, podocin, and urinary albumin-creatinine ratio (UACR) in patients with type 2 DM and albuminuria. Design: This is a cross-sectional study. Setting: This study was carried out in internal medicine outpatient clinic of Cipto Mangunkusumo Hospital Jakarta, Indonesia. Patients: This study consisted of 42 adults with type 2 DM and albuminuria. Measurements: The measurements include (1) Serum miRNA-21; (2) urinary podocin, nephrin, and albumin-creatinine ratio; and (3) serum miRNA-21 correlated to urinary podocin, nephrin, and albumin-creatinine ratio. Methods: The Spearman bivariate analysis to assess the correlation of miRNA-21 with nephrin, podocin, and UACR. Results: The mean relative expression of miRNA-21 was 0.069 (0.024), the median for nephrin, podocin, and UACR was 35.5 (15.75-51.25) ng/mL, 0.516 (0.442-0.545) ng/mL, and 150 (94.56-335.75) ng/mL, respectively. A correlation between miRNA-21 and nephrin was observed (r = 0.598; P < .0001). There was a correlation between miRNA-21 and UACR (r = 0.604; P < .0001). No correlation was found between miRNA-21 and podocin. Limitations: A lack of non-DM and non-albuminuric control population and small sample size. We could not exclude concurrent disease, and all other potential confounding variables, particularly those related to inflammation. Conclusions: The miRNA-21 can be considered an early biomarker for podocytopathy and albuminuria in DM, highlighting its potential for early diagnostic and therapeutic interventions. Further research is required to confirm these findings and explore their clinical applications, which could significantly alter management strategies for DKD.
Contexte: La maladie rénale diabétique (MRD) est la complication microvasculaire la plus fréquente et une des plus inquiétantes du diabète (DB). La podocytose est une composante clé des lésions glomérulaires en contexte de MRD. Le micro-ARN-21 (miARN-21) est un régulateur épigénétique impliqué dans les lésions podocytaires, mais les résultats des études précédentes n'ont pas résolu la controverse sur le rôle du miARN-21 dans la pathogenèse de la MRD. Objectif: Étudier la corrélation entre le taux de miARN-21 et la néphrine, la podocine et le rapport albumine-créatinine (RAC) urinaires chez les patients atteints de diabète de type 2 et présentant une albuminurie. Type d'étude: Étude transversale. Cadre: La clinique ambulatoire de médecine interne de l'hôpital Cipto Mangunkusumo à Jakarta (Indonésie). Sujets: 42 adultes diabétiques de type 2 présentant une albuminurie. Mesures: (1) miARN-21 sérique; (2) podocine, néphrine et rapport albumine-créatinine urinaires; (3) le miARN-21 sérique corrélé à la podocine, à la néphrine et au rapport albumine-créatinine urinaires. Méthodologie: L'analyse bivariée de Spearman a servi à évaluer la corrélation entre le taux de miARN-21 et la néphrine, la podocine et le rapport albumine-créatinine urinaires. Résultats: L'expression relative moyenne du miARN-21 était de 0,069 ng/ml (0,024). La médiane s'établissait à 35,5 (15,7551,25) ng/ml pour la néphrine, à 0,516 (0,4420,545) ng/ml pour la podocine et à 150 (94,56335,75) ng/ml pour le RAC. On a observé une corrélation entre le miARN-21 et la néphrine (r = 0,598; p = < 0,0001), de même qu'entre le miARN-21 et le RAC (r = 0,604; p = <0,0001). Aucune corrélation n'a été observée entre le miARN-21 et la podocine. Limites: L'étude ne comporte pas de population témoin (non-DB et sans albuminurie) et l'échantillon est de petite taille. Il n'a pas été possible d'exclure les maladies concomitantes, de même que toutes les autres variables confondantes potentielles, en particulier celles qui sont liées à l'inflammation. Conclusion: Chez les patients diabétiques, le miARN-21 peut être considéré comme un biomarqueur précoce de la podocytose et de l'albuminurie, ce qui met en évidence son potentiel à faire partie des interventions diagnostiques et thérapeutiques précoces. D'autres recherches sont nécessaires pour confirmer ces résultats et explorer leurs applications cliniques, ce qui pourrait modifier considérablement les stratégies de prise en charge de la maladie rénale diabétique.
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Hypercholesterolemia-associated oxidative stress increases the formation of oxidized low-density lipoprotein (oxLDL), which can affect endothelial cell function and potentially contribute to renal dysfunction, as reflected by changes in urinary protein excretion. This study aimed to investigate the impact of exogenous oxLDL on urinary excretion of albumin and nephrin. LDL was isolated from a patient with familial hypercholesterolemia (FH) undergoing lipoprotein apheresis (LA) and was oxidized in vitro with Cu (II) ions. Biochemical markers of LDL oxidation, such as TBARS, conjugated dienes, and free ε-amino groups, were measured. Wistar rats were treated with a single intraperitoneal injection of PBS, LDL, or oxLDL (4 mg of protein/kg b.w.). Urine was collected one day before and two days after the injection. We measured blood lipid profiles, urinary protein excretion (specifically albumin and nephrin), and markers of systemic oxidative stress (8-OHdG and 8-iso-PGF2α). The results showed that injection of oxLDL increased urinary albumin excretion by approximately 28% (310 ± 27 µg/24 h vs. 396 ± 26 µg/24 h, p = 0.0003) but had no effect on nephrin excretion. Neither PBS nor LDL had any effect on urinary albumin or nephrin excretion. Additionally, oxLDL did not affect systemic oxidative stress. In conclusion, hypercholesterolemia may adversely affect renal function through oxidatively modified LDL, which interferes with the renal handling of albumin and leads to the development of albuminuria.
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Albuminuria , Lipoproteínas LDL , Estrés Oxidativo , Ratas Wistar , Lipoproteínas LDL/sangre , Lipoproteínas LDL/metabolismo , Animales , Humanos , Ratas , Albuminuria/orina , Masculino , Oxidación-Reducción , Proteínas de la Membrana/metabolismo , Hiperlipoproteinemia Tipo II/metabolismo , Hiperlipoproteinemia Tipo II/orinaRESUMEN
Steroid-resistant nephrotic syndrome (SRNS) is the second most frequent cause of chronic kidney disease before the age of 25 yr. Nephrin, encoded by NPHS1, localizes to the slit diaphragm of glomerular podocytes and is the predominant structural component of the glomerular filtration barrier. Biallelic variants in NPHS1 can cause congenital nephrotic syndrome of the Finnish type, for which, to date, no causative therapy is available. Recently, adeno-associated virus (AAV) vectors targeting the glomerular podocyte have been assessed as a means for gene replacement therapy. Here, we established quantitative and reproducible phenotyping of a published, conditional Nphs1 knockout mouse model (Nphs1tm1.1Pgarg/J and Nphs2-Cre+) in preparation for a gene replacement study using AAV vectors. Nphs1 knockout mice (Nphs1fl/fl Nphs2-Cre+) exhibited 1) a median survival rate of 18 days (range: from 9 to 43 days; males: 16.5 days and females: 20 days); 2) an average foot process (FP) density of 1.0 FP/µm compared with 2.0 FP/µm in controls and a mean filtration slit density of 2.64 µm/µm2 compared with 4.36 µm/µm2 in controls; 3) a high number of proximal tubular microcysts; 4) the development of proteinuria within the first week of life as evidenced by urine albumin-to-creatinine ratios; and 5) significantly reduced levels of serum albumin and elevated blood urea nitrogen and creatinine levels. For none of these phenotypes, significant differences between sexes in Nphs1 knockout mice were observed. We quantitatively characterized five different phenotypic features of congenital nephrotic syndrome in Nphs1fl/fl Nphs2-Cre+ mice. Our results will facilitate future gene replacement therapy projects by allowing for sensitive detection of even subtle molecular effects.NEW & NOTEWORTHY To evaluate potential, even subtle molecular, therapeutic effects of gene replacement therapy (GRT) in a mouse model, prior rigorous quantifiable and reproducible disease phenotyping is necessary. Here, we, therefore, describe such a phenotyping effort in nephrin (Nphs1) knockout mice to establish the basis for GRT for congenital nephrotic syndrome. We believe that our findings set an important basis for upcoming/ongoing gene therapy approaches in the field of nephrology, especially for monogenic nephrotic syndrome.
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Proteínas de la Membrana , Ratones Noqueados , Síndrome Nefrótico , Fenotipo , Podocitos , Animales , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Femenino , Masculino , Síndrome Nefrótico/genética , Síndrome Nefrótico/terapia , Podocitos/metabolismo , Modelos Animales de Enfermedad , Terapia Genética/métodos , Ratones , Vectores GenéticosRESUMEN
Podocytes are involved in maintaining kidney function and are a major focus of research on diabetic kidney disease (DKD). Urinary biomarkers derived from podocyte fragments and molecules have been proposed for the diagnosis and monitoring of DKD. Various methods have been used to detect intact podocytes and podocyte-derived microvesicles in urine, including centrifugation, visualization, and molecular quantification. Quantification of podocyte-specific protein targets and messenger RNA levels can be performed by Western blotting or enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, respectively. At present, many of these techniques are expensive and labor-intensive, all limiting their widespread use in routine clinical tests. While the potential of urinary podocyte markers for monitoring and risk stratification of DKD has been explored, systematic studies and external validation are lacking in the current literature. Standardization and automation of laboratory methods should be a priority for future research, and the added value of these methods to routine clinical tests should be defined.
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One of the most important side effects of Doxorubicin (DOX), a chemotherapeutic agent, is nephrotoxicity. The purpose of this study is to determine whether different doses of natural polyphenol Resveratrol (RSV) show antioxidative, anti-inflammatory or antiapoptotic effects in kidney tissue in DOX-induced nephrotoxicity and to detect how nephrin and OTULIN levels are affected in this process. A total of six equal groups made up of the 42 Sprague-Dawley rats utilized in the study (n = 7) were randomly assigned. Except for the control group (no treatment), all treatments were given intraperitoneally to the DOX (15 mg/kg), DOX + RSV I (15 mg/kg DOX+ 1 mg/kg/day RSV), DOX + RSV II (15 mg/kg DOX+ 5 mg/kg/day RSV), RSV I and RSV II groups. Kidney tissues taken from rats sacrificed on the fifteenth day were analyzed biochemically, histologically and immunohistochemically. Accordingly, it was determined that nephrin and OTULIN levels decreased in kidney tissue in DOX-induced nephrotoxicity. Furthermore, DOX caused oxidative stress, inflammation, and apoptosis, as well as histopathological changes in kidney tissue. However, it was observed that DOX-induced changes were regulated by RSV application. RSV was demonstrated to have antioxidant, anti-inflammatory and anti-apoptotic properties in dose-dependent DOX-induced nephrotoxicity. RSV may exert nephroprotective effects by modulating DOX-induced altered nephrin and OTULIN levels.
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Antioxidantes , Doxorrubicina , Ratas , Animales , Resveratrol/farmacología , Ratas Sprague-Dawley , Doxorrubicina/toxicidad , Antioxidantes/metabolismo , Estrés Oxidativo , Antiinflamatorios/farmacología , Apoptosis , RiñónRESUMEN
AIM: Minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are podocytopathies characterized by damage to the glomerular filtration barrier, leading to proteinuria and nephrotic syndrome. The production of anti-podocyte antibodies has been proposed as potential circulating factors contributing to the development of these conditions. The aim of the study is to evaluate the levels of anti-nephrin antibodies in patients with podocytopathies and healthy subjects. METHODS: In this study, a total of 77 patients with active glomerulopathy and 11 healthy subjects were included. Forty one patients were diagnosed with FSGS, 11 with MCD, and 25 with MN. To measure the levels of anti-nephrin antibodies, enzyme-linked immunosorbent assay was used. RESULTS: The levels of antibodies to nephrin were significantly higher in patients with MCD 61.2 [28.9-66.3] ng/mL and FSGS 32.5 [17.2-58.4] ng/mL compared to MN 20.3 [14.4-38.4] and healthy individuals 15.3 [12-18.9] ng/mL, p < .05. In patients with primary FSGS, the levels of antibodies to nephrin were significantly higher 45.2 [20-64.3] ng/mL compared to patients with secondary FSGS 26.7 [11.2-44.1] ng/mL, p < .05. There were no significant differences in the remission rate between the anti-nephrin antibodies positive and negative groups (log-rank test: p = .158). CONCLUSION: The level of anti-nephrin antibodies was found to be significantly higher in patients with MCD and pFSGS compared to those with sFSGS, MN, and healthy subjects. Anti-nephrin antibodies in MCD and primary FSGS may be associated with the severity of podocytopathies, however they did not have an impact on the response to therapy.
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Glomeruloesclerosis Focal y Segmentaria , Proteínas de la Membrana , Nefrosis Lipoidea , Síndrome Nefrótico , Adulto , Humanos , Glomeruloesclerosis Focal y Segmentaria/diagnóstico , Proyectos Piloto , Síndrome Nefrótico/diagnóstico , Síndrome Nefrótico/tratamiento farmacológico , Nefrosis Lipoidea/tratamiento farmacológico , Nefrosis Lipoidea/diagnóstico , AnticuerposRESUMEN
BACKGROUND: Both early recognition of glomerular injury and diagnosis of renal injury remain important problems in clinical settings, and current diagnostic biomarkers have limitations. The aim of this review was to determine the diagnostic accuracy of urinary nephrin for detecting early glomerular injury. METHODS: A search was conducted through electronic databases for all relevant studies published until January 31, 2022. The methodological quality was evaluated using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Pooled sensitivity, specificity, and other estimates of diagnostic accuracy were determined using a random effect model. The Summary Receiver Operating Characteristics (SROC) was used to pool the data and to estimate the area under the curve (AUC). RESULTS: The meta-analysis included 15 studies involving 1587 participants. Overall, the pooled sensitivity of urinary nephrin for detecting glomerular injury was 0.86 (95% CI 0.83-0.89) and specificity was 0.73 (95% CI 0.70-0.76). The AUC-SROC to summarise the diagnostic accuracy was 0.90. As a predictor of preeclampsia, urinary nephrin showed a sensitivity of 0.78 (95% CI 0.71-0.84) and specificity of 0.79 (95% CI 0.75-0.82), and as a predictor of nephropathy the sensitivity was 0.90 (95% CI 0.87-0.93), and specificity was 0.62 (95% CI 0.56-0.67). A subgroup analysis using ELISA as a method of diagnosis showed a sensitivity of 0.89 (95% CI 0.86-0.92), and a specificity of 0.72 (95% CI 0.69-0.75). CONCLUSION: Urinary nephrin may be a promising marker for the detection of early glomerular injury. ELISA assays appear to provide reasonable sensitivity and specificity. Once translated into clinical practice, urinary nephrin could provide an important addition to a panel of novel markers to help in the detection of acute and chronic renal injury.
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Enfermedades Renales , Glomérulos Renales , Femenino , Embarazo , Humanos , Sensibilidad y Especificidad , Curva ROC , Proteínas de la MembranaRESUMEN
Possible roles of anti-nephrin antibodies in post-transplant recurrent focal segmental glomerulosclerosis (FSGS) have been reported recently. To confirm these preliminary results, we performed a multi-institutional study of 22 Japanese pediatric kidney transplant recipients with FSGS including eight genetic FSGS and 14 non-genetic (presumed primary) FSGS. Eleven of the 14 non-genetic FSGS patients had post-transplant recurrent FSGS. Median (interquartile range) plasma levels of anti-nephrin antibodies in post-transplant recurrent FSGS measured using ELISA were markedly high at 899 (831, 1292) U/mL (cutoff 231 U/mL) before transplantation or during recurrence. Graft biopsies during recurrence showed punctate IgG deposition co-localized with nephrin that had altered localization with increased nephrin tyrosine phosphorylation and Src homology and collagen homology A expressions. Graft biopsies after remission showed no signals for IgG and a normal expression pattern of nephrin. Anti-nephrin antibody levels decreased to 155 (53, 367) U/mL in five patients with samples available after remission. In patients with genetic FSGS as in those with non-genetic FSGS without recurrence, anti-nephrin antibody levels were comparable to those of 30 control individuals, and graft biopsies had no signals for IgG and a normal expression pattern of nephrin. Thus, our results suggest that circulating anti-nephrin antibodies are a possible candidate for circulating factors involved in the pathogenesis of post-transplant recurrent FSGS and that this may be mediated by nephrin phosphorylation. Larger studies including other ethnicities are required to confirm this finding.
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Glomeruloesclerosis Focal y Segmentaria , Trasplante de Riñón , Humanos , Niño , Glomeruloesclerosis Focal y Segmentaria/patología , Trasplante de Riñón/efectos adversos , Trasplante de Riñón/métodos , Proteínas de la Membrana/genética , Inmunoglobulina G , RecurrenciaRESUMEN
BACKGROUND: Hypertensive disorders in pregnancy are one of the leading causes of maternal and perinatal morbidity and mortality worldwide. The clinical utility of urinary nephrin as a diagnostic biomarker of preeclampsia is currently of research interest. However, this is yet to gain significant traction within clinical settings. OBJECTIVES: We evaluated the association between maternal urinary nephrin levels and the occurrence and severity of preeclampsia among pregnant women in Lagos, Nigeria. DESIGN: We conducted an analytical cross-sectional study involving pregnant women diagnosed with preeclampsia as well as their age- and gestational-age-matched normotensive counterparts. We tested the association between high maternal urinary nephrin levels and the occurrence of preeclampsia without and with severe features. P < 0.05 was reported as statistically significant. RESULTS: The study showed that for every unit increase in urinary nephrin levels, the odds of preeclampsia increased by about ninefold (adjusted Odds ratio = 8.9, 95% confidence interval: 2.8-29.2, P < 0.001). The levels of urinary nephrin increased steadily with increasing severity of the disease: 1.9 ± 0.8 ng/mL in preeclampsia without severe features, 2.7 ± 0.7 ng/mL in preeclampsia with at least one severe feature, and 3.3 ±1.1 ng/mL in eclampsia. CONCLUSION: There was an association between elevated levels of urinary nephrin and preeclampsia and its severe variant. However, there is a need for more robust studies with a longitudinal characterization of urinary nephrin levels to establish causal relationships with preeclampsia, explore other potential risk factors of preeclampsia, and define the clinical usefulness of urinary nephrin as a potentially reliable and accurate predictive marker of preeclampsia among women in low- and middle-income countries (LMIC) settings.