Effect of fetal growth restriction on urinary podocalyxin levels at birth in preterm neonates.

BACKGROUND: Small-for-gestational-age (SGA) neonates are at a higher risk of adult-onset metabolic disorders because of fetal programming in the presence of growth restriction. Nephrogenesis may also be affected in fetal growth restriction. This study hypothesized that urinary podocalyxin levels, a marker of nephrogenesis, would be lower among preterm SGA neonates as compared to appropriate-for-gestational-age (AGA) controls. METHODS: This cross-sectional study enrolled gestation-matched SGA (n = 90) and AGA (n = 45) neonates born at 260-366 weeks of gestation. The SGA group comprised of 45 neonates with birth weight between 3rd and 10th centile and 45 neonates with birth weight <3rd centile. The primary outcome of the study was the difference in urinary podocalyxin levels between SGA and AGA neonates. Glomerular and tubular functions were also assessed. RESULTS: Urinary podocalyxin levels were similar in SGA and AGA neonates (ng/mg of creatinine; median [interquartile range]: 28.7 [4.8-70.2] vs. 18.7 [3.1-55.9]), P value 0.14). No correlation was observed between birth weight centile and urinary podocalyxin levels (r: -0.06). Glomerular filtration rate, fractional excretion of sodium, and serum ß-2-microglobulin levels were comparable across the study groups. CONCLUSIONS: Glomerular development as assessed by urinary podocalyxin levels and renal functions are comparable in SGA and AGA preterm neonates. IMPACT: Neonates born with fetal growth restriction are at a higher risk of adult-onset metabolic disorders because of fetal programming. This cross-sectional study investigated the effect of presence and severity of fetal growth restriction on glomerular development by measuring urinary podocalyxin levels in preterm infants. This study did not observe any effect of the presence or severity of fetal growth restriction on urinary podocalyxin levels and other markers of glomerular and renal tubular functions.

Role of urinary podocalyxin in early diagnosis of diabetic nephropathy.

Introduction. Podocyte injury has been reported as an early feature of DN therefore, the assessment of podocyte injury can be accomplished by estimation of podocalyxin in urine. This study aimed to estimate the urinary podocalyxin levels and to determine the sensitivity and specificity of this biomarker for early detection of DN.Materials and methods. A total of 90 patients with type 2 diabetes mellitus (T2DM) were included in this cross-sectional study. Sixty of them were without diagnosed DN, and 30 with diagnosed DN. A control group consisted of 30 healthy subjects. All patients with T2DM were divided into three subgroups according to urinary microalbumin/creatinine ratio (UM/CR): normoalbuminuric, microalbuminuric and macroalbuminuric patients. Urine samples, were used for measurement of podocalyxin by ELISA, creatinine and microalbumin. Fasting venous blood samples was collected for biochemical analyses.Results. The levels of urinary podocalyxin (u-PDX) were higher in patients with T2DM compared to control subjects and a statistically significant difference among studied subgroups regarding u-PDX was found (p < 0.05). Levels of u-PDX are increasing gradually with the degree of DN (p < 0.029). u-PDX levels were positively correlated with UM/CR (r = 0.227, p = 0.002). A cut-off level of 43.8 ng/ml u-PDX showed 73.3% sensitivity and 93.3% specificity to detect DN in early stage. A cut-off level of 30 mg/g UM/CR showed 41.5% sensitivity and 90% specificity in predicting DN. u-PDX was elevated in 48,2% of normoalbuminuric patients.Conclusion. Urinary podocalyxin be useful and more sensitive and specific marker in early detection of DN than microalbuminuria.

Association between Renal Podocalyxin Expression and Renal Dysfunction in Patients with Diabetic Nephropathy: A Single-Center, Retrospective Case-Control Study.

This retrospective study investigated whether podocalyxin expression in renal biopsies and urine of patients with diabetic nephropathy (DN) is associated with renal function. This retrospective study included 32 patients with nephropathy, secondary to type 2 diabetes treated at the First Hospital of Lanzhou University (January 2010 to January 2015). Compared with the control group, the DN group had a significantly lower renal expression of podocalyxin and higher urinary podocalyxin/creatinine ratio. Patients with DN were divided into the high and low expression groups according to podocalyxin expression in renal tissues. Patients in the low expression group had longer diabetes duration, lower plasma albumin and eGFR, higher glycated hemoglobin (HbA1c), 24 h urinary protein, serum creatinine, and urinary podocalyxin/creatinine ratio, and more severe glomerular, tubulointerstitial, and renal interstitial inflammation than patients in the high expression group (all P < 0.01). The renal survival rate was significantly lower in the low expression group than in the high expression group (P < 0.01). Single-factor Cox regression analysis showed that reduced podocalyxin expression and increased urinary podocalyxin excretion were associated with poor renal outcome. Measuring podocalyxin levels in renal tissues and urine could help evaluate the progression of DN.

Kidney transplant monitoring by urinary flow cytometry: Biomarker combination of T cells, renal tubular epithelial cells, and podocalyxin-positive cells detects rejection.

Creatinine and proteinuria are used to monitor kidney transplant patients. However, renal biopsies are needed to diagnose renal graft rejection. Here, we assessed whether the quantification of different urinary cells would allow non-invasive detection of rejection. Urinary cell numbers of CD4+ and CD8+ T cells, monocytes/macrophages, tubular epithelial cells (TEC), and podocalyxin(PDX)-positive cells were determined using flow cytometry and were compared to biopsy results. Urine samples of 63 renal transplant patients were analyzed. Patients with transplant rejection had higher amounts of urinary T cells than controls; however, patients who showed worsening graft function without rejection had similar numbers of T cells. T cells correlated with histological findings (interstitial inflammation p = 0.0005, r = 0.70; tubulitis p = 0.006, r = 0.58). Combining the amount of urinary T cells and TEC, or T cells and PDX+ cells, yielded a significant segregation of patients with rejection from patients without rejection (all p < 0.01, area under the curve 0.89-0.91). Urinary cell populations analyzed by flow cytometry have the potential to introduce new monitoring methods for kidney transplant patients. The combination of urinary T cells, TEC, and PDX-positive cells may allow non-invasive detection of transplant rejection.

Urinary podocalyxin: Is it a real index of disease activity in egyptian patients lupus nephritis?

Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease characterized by production of a number of antinuclear antibodies. Podocyte injury is an important feature and can be detected by several markers including podocalyxin. We aimed to evaluate the impact of SLE on urinary levels of podocalyxin and to determine its relationship to renal biopsy, proteinuria, and disease activity in lupus nephritis (LN) patients. Sixty individuals were recruited; 30 SLE patients with LN as well as 30 healthy volunteers and they were subjected to full history, clinical examination, kidney function, protein/creatinine ratio, urinary podocalyxin, and kidney biopsy. Patients with LN had higher level of urinary podocalyxin (3.96 ± 2.24) than the other group (0 ± 0), (P <0.001). Class IV LN was the most common class found among LN patients [18 cases (60%)]. There was a statistically significant positive correlation between SLE disease activity index score, protein/creatinine ratio, and urinary podocalyxin (P <0.001, r = 0.98) (P <0.001, r = 0.765). There was a statistically significant negative correlation between serum albumin, serum calcium, and urinary podocalyxin (P = 0.001, r = -0.589) (P = 0.025, r = -0.407). Urinary podocalyxin level significantly predicts the pathological impact of SLE on the kidney and could be used as a noninvasive marker for such effect and its progression.

Evaluation of the urinary podocalyxin and nephrin excretion levels to determine a safe time interval between two sessions of SWL for renal stones: a non randomized exploratory study.

OBJECTIVES: We aimed to evaluate the role of nephrin and podocalyxin in determining the intervals between shock wave lithotripsy (SWL) sessions and how soon the kidney damage was recovered. METHODS: This work was a prospective study that included 30 patients with unilateral kidney stones. The patients' midflow urine samples were collected before SWL and 1 h, 1 day and 1 week after the procedure. Nephrin and podocalyxin levels in the urine samples were measured by the enzyme-linked immunosorbent assay method. RESULTS: Among the 30 patients who underwent SWL, 19 were males and 11 were females. The mean age of the SWL group was 34.7 ± 13.2. Both biomarkers did not correlate with age, creatinine values, body mass index, stone side, stone size, energy, frequency and shock numbers. Nephrin and podocalyxin levels were significantly higher at the pre-SWL point (p < 0.05). After the procedure, a significant decrease was observed in both biomarker levels (p < 0.05). At the end of first day, these levels started to increase progressively up to the end of the first week (p > 0.05). CONCLUSIONS: Nephrin and podocalyxin may help to determine early period kidney damage associated with SWL. Post-SWL podocalyxin and nephrin values may be used to determine the interval between SWL sessions.

Tandem mass spectrometry analysis of urinary podocalyxin and podocin in the investigation of podocyturia in women with preeclampsia and Fabry disease patients.

BACKGROUND: Podocytes are highly differentiated visceral cells, and several related specific proteins, such as podocalyxin and podocin are potential tools for the evaluation of podocyturia. However, precise quantitation of podocyturia-related proteins is complex and often unreliable. METHOD: A reversed-phase ultra-performance liquid chromatography coupled to tandem mass spectrometry method was developed and validated to quantify podocalyxin and podocin levels in urine supernatant by using specific cleavable peptides and standards. Urine samples from women with normotensive or hypertensive pregnancies, gestational diabetes and preeclampsia, as well as treated and untreated Fabry patients, and gender-matched controls were investigated. RESULTS: The multiplex analysis shows that podocalyxin levels were higher than podocin levels in patients, the former being particularly higher in pregnant women. Women with preeclampsia had abnormal urine levels of both proteins with a higher sensitivity for podocalyxin. Slightly increased levels of podocin were also observed in Fabry males, while both proteins were increased in untreated Fabry females. Correlations were established between podocalyxin and podocin levels and clinical parameters associated with Fabry disease and preeclampsia. CONCLUSIONS: This methodology makes possible the precise, simultaneous and reliable analysis of podocalyxin and podocin levels, and offers a valuable tool for the evaluation of podocyturia.

Long term follow up of biomarkers of podocyte damage and renal function in patients with and without preeclampsia / Seguimento de longo prazo com biomarcadores de dano podocitário e função renal em pacientes com e sem pré-eclâmpsia

ABSTRACT Introduction: preeclampsia can be associated with future renal disease. Objectives: To measure changes in renal function overtime in patients with preeclampsia. Methods: urine and serum samples from eleven patients with preeclampsia and eight patients with a normal pregnancy were obtained during pregnancy, postpartum, and 3 years after delivery. Urine podocalyxin, protein, and serum creatinine were measured. Results: after 3 years, there were no significant differences in urinary podocalyxin in patients with or without preeclampsia: 4.34 ng/mg [2.69, 8.99] vs. 7.66 ng/mg [2.35, 13], p = 0.77. The same applied to urinary protein excretion: 81.5 mg/g [60.6, 105.5] vs. 43.2 mg/g [20.9, 139.3] p = 0.23. Serum creatinine was 0.86 mg/dL [0.7, 0.9] vs. 0.8 mg/dL [0.68, 1] p = 0.74 in those with and without preeclampsia. In normal patients, urinary podocalyxin decreased from 54.4 ng/mg [34.2, 76.9] during pregnancy to 7.66 ng/mg [2.35, 13] three years after pregnancy, p = 0.01. Proteinuria decreased from 123.5 mg/g [65.9, 194.8] to 43.2 mg/g [20.9, 139.3], p = 0.12. In preeclampsia patients, urinary podocalyxin decreased from 97.5 ng/mg [64.9, 318.4] during pregnancy to 37.1 ng/mg within one week post-partum [21.3, 100.4] p = 0.05 and 4.34 ng/mg [2.69, 8.99] three years after, p = 0.003. Proteinuria was 757.2 mg/g [268.4, 5031.7] during pregnancy vs. 757.2 mg/g [288.2, 2917] postpartum, p = 0.09 vs. 81.5 mg/g [60.6, 105.5] three years later, p = 0.01. Two patients still had proteinuria after 3 years. Conclusions: in preeclampsia patients, postpartum urinary podocalyxin decreased before proteinuria. After three years, serum creatinine, urinary podocalyxin, and protein tended to normalize, although some patients still had proteinuria.

RESUMO Introdução: a pré-eclâmpsia pode estar associada à doença renal no futuro. Objetivos: medir mudanças na função renal ao longo do tempo em pacientes com pré-eclâmpsia. Métodos: amostras de urina e soro de onze pacientes com pré-eclâmpsia e oito pacientes com gravidez normal foram obtidas durante a gravidez, pós-parto e 3 anos após o parto. Medimos podocalixina na urina, proteína e creatinina sérica. Resultados: após 3 anos, não houve diferenças significativas na podocalixina urinária em pacientes com ou sem pré-eclâmpsia: 4,34 ng/mg [2,69, 8,99] versus 7,66 ng/mg [2,35, 13], p = 0,77. O mesmo se aplicou à excreção urinária de proteínas: 81,5 mg/g [60,6, 105,5] vs. 43,2 mg/g [20,9, 139,3] p = 0,23. A creatinina sérica foi de 0,86 mg/dL [0,7, 0,9] vs. 0,8 mg/dL [0,68, 1] p = 0,74 naqueles com e sem pré-eclâmpsia. Em pacientes normais, a podocalixina urinária diminuiu de 54,4 ng/mg [34,2, 76,9] durante a gestação para 7,66 ng/mg [2,35, 13] três anos após a gravidez, p = 0,01. A proteinúria diminuiu de 123,5 mg/g [65,9, 194,8] para 43,2 mg/g [20,9, 139,3], p = 0,12. Em pacientes com pré-eclâmpsia, a podocalixina urinária diminuiu de 97,5 ng/mg [64,9, 318,4] durante a gravidez para 37,1 ng/mg em uma semana de pós-parto [21,3, 100,4] p = 0,05 e 4,34 ng/mg [2,69, 8,99] três anos depois, p = 0,003. A proteinúria foi de 757,2 mg/g [268.4, 5031.7] durante a gravidez vs. 757,2 mg/g [288.2, 2917] pós-parto, p = 0.09 vs. 81.5 mg/g [60.6, 105.5] três anos depois, p = 0.01. Dois pacientes ainda apresentavam proteinúria após 3 anos. Conclusões: em pacientes com pré-eclâmpsia, a podocalixina urinária pós-parto diminuiu antes da proteinúria. Após três anos, a creatinina sérica, a podocalixina urinária e a proteína tenderam a se normalizar, embora alguns pacientes ainda tivessem proteinúria.

Urine markers of podocyte dysfunction: a review of podocalyxin and nephrin in selected glomerular diseases.

Urinary podocalyxin and nephrin are urine markers of podocyte dysfunction that may reflect the integrity of kidney's filtration barrier. Studies on their respective roles in glomerular diseases are still underway. However, the isolated and unsystematic manner in which they are being studied does not permit proper identification of their roles in each glomerular disease. As such, there is little or no appreciation of what research has already achieved and what remains to be achieved as the research direction is not clearly defined. We explored the recent studies and outlined the major findings regarding the value of both biomarkers in each of the three glomerular disease entities. Our review covered diabetic nephropathy, membranous nephropathy and IgA nephropathy.

MIF/CD74 axis is a target for metformin therapy in diabetic podocytopathy - real world evidence.

Introduction：To observe the effects of metformin on urinary excretion of MIF, CD74 and podocalyxin in type 2 diabetics and to explore its possible renoprotective mechanisms. METHODS: 202 uncontrolled type 2 diabetics, who were previously prescribed sulfonylurea monotherapy(n=100) or sulfonylurea in combination with metformin (n=102) were enrolled in the study. The amount of macrophage migration inhibitory factor(MIF) and CD74 in serum, urinary MIF to creatine ratio(UMCR), urinary CD74 to creatine ratio(UCCR), urinary albumin to creatine ratio(UACR) and urinary podocalyxin to creatine ratio (UPCR) were determined. RESULTS: Metabolic parameters including fasting blood glucose, postprandial 2 hours blood glucose, hemoglobin A1c, MIF and CD74 in serum were comparable between the two groups. Moreover, metformin add-on therapy showed significantly better efficacy in reducing UMCR, UCCR, UPCR and UACR in comparison with those in sulfonylurea monotherapy group, respectively. UPCR had positive correlation with UACR, UMCR and UCCR (r＝0.73, r=0.69, r=0.62, P < 0.01), respectively. CONCLUSIONS: Metformin could present its podocyte-protective capacity in type 2 diabetics and the underlying mechanisms may be partly attributed to its effects in suppressing MIF-CD74 axis mediated inflammatory cascade response. < p > < /p >.

Long term follow up of biomarkers of podocyte damage and renal function in patients with and without preeclampsia.

INTRODUCTION: preeclampsia can be associated with future renal disease. OBJECTIVES: To measure changes in renal function overtime in patients with preeclampsia. METHODS: urine and serum samples from eleven patients with preeclampsia and eight patients with a normal pregnancy were obtained during pregnancy, postpartum, and 3 years after delivery. Urine podocalyxin, protein, and serum creatinine were measured. RESULTS: after 3 years, there were no significant differences in urinary podocalyxin in patients with or without preeclampsia: 4.34 ng/mg [2.69, 8.99] vs. 7.66 ng/mg [2.35, 13], p = 0.77. The same applied to urinary protein excretion: 81.5 mg/g [60.6, 105.5] vs. 43.2 mg/g [20.9, 139.3] p = 0.23. Serum creatinine was 0.86 mg/dL [0.7, 0.9] vs. 0.8 mg/dL [0.68, 1] p = 0.74 in those with and without preeclampsia. In normal patients, urinary podocalyxin decreased from 54.4 ng/mg [34.2, 76.9] during pregnancy to 7.66 ng/mg [2.35, 13] three years after pregnancy, p = 0.01. Proteinuria decreased from 123.5 mg/g [65.9, 194.8] to 43.2 mg/g [20.9, 139.3], p = 0.12. In preeclampsia patients, urinary podocalyxin decreased from 97.5 ng/mg [64.9, 318.4] during pregnancy to 37.1 ng/mg within one week post-partum [21.3, 100.4] p = 0.05 and 4.34 ng/mg [2.69, 8.99] three years after, p = 0.003. Proteinuria was 757.2 mg/g [268.4, 5031.7] during pregnancy vs. 757.2 mg/g [288.2, 2917] postpartum, p = 0.09 vs. 81.5 mg/g [60.6, 105.5] three years later, p = 0.01. Two patients still had proteinuria after 3 years. CONCLUSIONS: in preeclampsia patients, postpartum urinary podocalyxin decreased before proteinuria. After three years, serum creatinine, urinary podocalyxin, and protein tended to normalize, although some patients still had proteinuria.

Urinary podocyte-associated molecules and albuminuria in hypertension.

OBJECTIVE: Hypertension-induced podocyte damage and the relationship with UAE is analyzed in diabetic and nondiabetic participants. PATIENTS AND METHODS: Sixty-four hypertensive patients, 30 diabetics, with glomerular filtration rate (eGFR) greater than 60 ml/min per 1.73 m were included. Urinary albumin excretion was measured in morning urine using a nephelometric immunoassay and expressed as albumin/creatinine ratio. Urinary pellets were obtained from fresh urine and mRNA was assessed by real-time quantitative PCR. Likewise, protein podocyte-specific molecules were measured by western blot using specific antibodies. RESULTS: Fourteen nondiabetics and 20 diabetics had increased UAE greater than 30 mg/g. In individuals with increased EUA, the mRNA expression of nephrin and CD2AP was low in diabetics, whereas only nephrin mRNA in nondiabetics. No differences were observed in podocalyxin and aquaporin-1 mRNA levels. Concerning the protein values, in both nondiabetic and diabetic patients, nephrin, CD2AP and podocalyxin were increased in patients with increased UAE, with no differences in aquaporin-1. A significant positive relationship was observed between log UAE and nephrin protein values, and an inverse association observed with mRNA. CONCLUSION: Hypertensive patients who had elevated UAE showed increased urinary excretion of podocyte-specific proteins coupled with a phenotype of decreased mRNA expression. The phenotype of podocyte-specific mRNA and the increment of nephrin can be used as a valuable marker of early glomerular injury.

Biomarkers of glomerular dysfunction in pre-eclampsia - A systematic review.

BACKGROUND: Early detection of pre-eclampsia remains one of the major focuses of antenatal obstetric care. There is often a delay in the diagnosis, mainly due to the non-specific nature of the condition. Podocytes which play a pivotal role in glomerular function become injured in pre-eclampsia leading to subsequent proteinuria. Our aim was to review available studies to determine the clinical utility of biomarkers of podocyte injury in pre-eclampsia. METHODS: We used QUADAS (Quality Assessment of Diagnostic Accuracy Studies) criteria to perform a systematic review of the literature to determine the clinical utility of podocyte injury biomarkers in predicting pre-eclampsia. RESULTS: This study identified five potential renal biomarkers including podocytes, nephrin, synaptopodin, podocin and podocalyxin. The pooled sensitivity of all biomarkers was 0.78 (95% CI 0.74-0.82) with a specificity of 0.82 (95% CI 0.79-0.85). The area under the Summary of Receiver Operating Characteristics Curve (SROC) was 0.926 (SE 0.30). Urinary nephrin achieved the highest diagnostic values with a sensitivity of 0.81 (95% CI 0.72-0.88) and specificity of 0.84 (95% CI 0.79-0.84). CONCLUSION: Biomarkers of glomerular injury show promise as diagnostic aids in pre-eclampsia. A large-scale prospective cohort study is warranted before these biomarkers can be recommended for routine clinical care.

The correlation of urinary podocytes and podocalyxin with histological features of lupus nephritis.

Objectives The objective of this study was to test the correlation of urinary podocyte number (U-Pod) and urinary podocalyxin levels (U-PCX) with histology of lupus nephritis. Methods This was an observational, cross-sectional study. Sixty-four patients were enrolled: 40 with lupus nephritis and 24 without lupus nephritis (12 lupus nephritis patients in complete remission and 12 systemic lupus erythematosus patients without lupus nephritis). Urine samples were collected before initiating treatment. U-Pod was determined by counting podocalyxin-positive cells, and U-PCX was measured by sandwich ELISA, normalized to urinary creatinine levels (U-Pod/Cr, U-PCX/Cr). Results Lupus nephritis patients showed significantly higher U-Pod/Cr and U-PCX/Cr compared with patients without lupus nephritis. U-Pod/Cr was high in proliferative lupus nephritis (class III±V/IV±V), especially in pure class IV (4.57 (2.02-16.75)), but low in pure class V (0.30 (0.00-0.71)). U-Pod/Cr showed a positive correlation with activity index ( r=0.50, P=0.0012) and was independently associated with cellular crescent formation. In contrast, U-PCX/Cr was high in both proliferative and membranous lupus nephritis. Receiver operating characteristic analysis revealed significant correlation of U-Pod/Cr with pure class IV, class IV±V and cellular crescent formation, and the combined values of U-Pod/Cr and U-PCX/Cr were shown to be associated with pure class V. Conclusions U-Pod/Cr and U-PCX/Cr correlate with histological features of lupus nephritis.

[Shendi granules regulates the balance of T cell subsets and down-regulates podocalyxin in rats with mesangial proliferative glomerulonephritis].

Objective To observe the effect of Shendi granules on T cell subsets and podocyte marker protein in rats with mesangial proliferative glomerulonephritis (MsPGN), and study possible mechanism. Methods Totally 40 SD rats were randomly divided into the model group, valsartan group, Shendi granule group and normal group. The Shendi granule group were given 4 g/(kg.d) of Shendi granule by gavage; the valsartan group were given 10.3 mg/(kg.d) of valsartan by gavage; the model group and normal group were given the same amount of saline per day by gavage. The treatments lasted 12 weeks. Routine biochemical method was used to quantify 24-hour urine protein; the numbers of CD4+ and CD8+ T cells were detected by flow cytometry; the serum levels of interleukin 2 (IL-2), IL-4 and IL-17, the levels of urinary podocalyxin (PCX) and B7-1, the renal calcineurin (CaN) content were determined by ELISA. Results Compared with the normal group, the levels of 24-hour urine protein, CD8+ T cells, serum IL-2 and IL-17, urinary PCX and B7-1, CaN in the model group were higher. The above indexes in the valsartan group and control group were lower than those in the model group, they were lower in the Shendi granule group than in the valsartan group. The whole blood CD4+ T cell number and serum IL-4 level in the model group were lower than those in the normal group, they were higher in the valsartan group and control group than in the model group. Compared with the valsartan group, the Shendi granule group had a better improvement. Conclusion Shendi granule could reduce 24-hour urine protein effectively. The mechanism may be related to the regulation of CD4+ T and CD8+ T cell numbers, the down-regulated expressions of serum IL-2, IL-17, the decreased levels of PCX and B7-1 in urine, CaN in kidney tissue, and the up-regulated level of serum IL-4.

Urinary podocalyxin as a possible novel marker of intrauterine nephrogenesis and extrauterine podocyte injury.

BACKGROUND: The number of nephrons at birth is determined during fetal development and is modulated thereafter by postnatal podocyte injury. Hyperfiltration, caused by a reduced number of nephrons, is a risk factor for chronic kidney disease. It is therefore important to monitor the formation of nephrons. METHODS: Urine samples were collected from infants within 1-2 days of birth, with follow-up sampling for preterm infants at 37-39 weeks of corrected age. Urinary levels of podocalyxin (PCX), ß2-microglobulin (ß2MG), N-acetyl-ß-D-glucosaminidase (NAG), total protein (TP), microalbumin (mAlb) and creatinine were measured and the relationship between these markers evaluated. RESULTS: Seventy-nine neonates were enrolled in this study. Urinary levels of PCX at birth were higher than normal adult reference values, with levels increasing up to a gestational age of 36 weeks (p = 0.0242). At 37-39 weeks corrected age, urinary levels of PCX decreased to adult levels. The levels of PCX in the urine at birth were not correlated to urinary levels of ß2MG, NAG, TP and mAlb. CONCLUSIONS: An increased urinary level of PCX may be a marker of both active nephron formation and podocyte injury sustained at birth. As such, changes in urinary levels of PCX are likely to reflect adaptation of renal function to the extra-uterine environment.

The Podocyte Count Detected by an Improved Immunocytochemical Method has Higher Diagnostic Efficiency than Enzyme-Linked Immunosorbent Assay and Serum Cystatin C to Evaluate the Early Stage Damage of Glomerular.

BACKGROUND: In renal diseases, earlier injury to glomerular may lead to the abscission of podocyte. The number of podocyte in urine may reflect the severity of glomerular damage. Podocalyxin (PCX) was considered as a podocyte marker. Many methods were used to detect podocyte. Applications of these methods were limited by tricky, expensive, and low accuracy. Here, we improved an immunocytochemical method to count the number of podocyte in urine. METHODS: In this study, we counted the numbers of podocyte in urine by our improved method and detected the PCX levels in urine by enzyme-linked immunosorbent assay (ELISA) in glomerulopathy patients and healthy controls. The serum levels of cystatin C (CysC), blood urea nitrogen (BUN), creatinine (CR), uric acid (URIC), and ß2-Microglobulin (ß2-MG) in all subjects were detected. Correlation analysis and diagnostic efficiencies comparisons among immuocytochemical method, ELISA, and the biochemistry index were also performed. RESULTS: The podocyte counts in patients were significantly higher than controls. Podocytes counts positively correlated with PCX concentrations and the serum CysC. The podocyte count had higher diagnostic efficiency than PCX concentrations detected by ELISA and serum CysC. CONCLUSIONS: The podocyte count detected by our improved method had higher diagnostic efficiency than ELISA and serum CysC.

Urinary podocalyxin, the novel biomarker for detecting early renal change in obesity.

BACKGROUND: The prevalence of obesity is increasing during the past decade along with obesity-related glomerulopathy (ORG), glomeruli injury due to the obesity. The major pathogenesis of ORG is the shedding of podocytes from the glomerular cell barrier into urine. Podocalyxin (PCX), a main surface antigen of podocyte, correlates well with glomerulosclerosis progression and glomerular injury severity, and might be a potential biomarker for early renal alteration in obesity. In addition, vascular endothelial growth factor (VEGF) and alpha-smooth muscle actin (α-SMA) also play a role in promoting glomerulosclerosis. The aim of this study was to explore whether obese subjects without other diseases excrete more PCX-positive (PCX+) cells than non-obese individuals, in comparison with urine protein-creatinine ratio (UPCR) and glomerular filtration rate (GFR) as traditional renal markers. Moreover, the effect of body mass index (BMI) on urinary VEGF, PCX or α-SMA positive cells was also investigated. METHODS: Forty-eight obese and 13 non-obese adults were included. Exfoliated cells from fresh first void morning urine were harvested, stained with PCX, VEGF, and α-SMA antibody, and quantified by flow cytometry. Correlation between interested urinary biomarkers (cells positive for PCX, VEGF plus PCX and α-SMA), UPCR and GFR with BMI and metabolic risk factors were analyzed. RESULTS: Obese patients had significantly higher PCX+ cells than non-obese [0.62 (0.00-13.13) vs. 0.15 (0.00-0.72) cells/ml × mg cr, p < 0.05]. There was no significant difference in GFR and UPCR between the groups. Of interest, BMI demonstrated a correlation with PCX+ cells (r = 0.343, p = 0.008) and cells positive for PCX plus VEGF (r = 0.374, p = 0.004). CONCLUSION: Obese subjects without other diseases and with normal UPCR and GFR showed evidence of renal alteration through the detection of a higher number of PCX+ cells. Increasing BMI also resulted in higher number of PCX+ cells.