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Li X, Zou T, Wang S, Wu H, Wu M, Liu Z, Liu H. Mechanism and restoration strategy of lysosomal abnormalities induced by urinary protein overload in proximal tubule epithelial cells. Dev Dyn 2021; 250:943-954. [PMID: 33410225 DOI: 10.1002/dvdy.297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 12/23/2020] [Accepted: 12/25/2020] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Persistent elevated concentrations of urinary protein can destroy proximal tubule epithelial cells (PTECs) by inducing lysosomal abnormalities, thereby aggravating PTEC damage and renal fibrosis. However, the specific mechanisms of these serial biochemical events and methods for treating or preventing PTEC damage upon proteinuria need further investigation. RESULTS In this study, electron microscopy and dual-labeled immunofluorescence analysis for identifying lysosome type revealed inadequate primary lysosome biogenesis and secondary lysosome accumulation in the PTECs of patients with minimal change nephrotic syndrome or membranous nephropathy who suffered from proteinuria. In vitro studies on HK-2 cells indicated that this abnormality was associated with decreased expression of transcription factor EB (TFEB). In contrast, TFEB overexpressing HK-2 cells under urinary protein overload exhibited significantly reduced accumulation of secondary lysosomes and increased proportion and quantity of primary lysosomes as indicated by dual-labeled immunofluorescence. Further, these cells could upregulate lysosomal degradation functions, as determined using Cathepsin L activity assays and flow cytometry for dye quenched-albumin. CONCLUSIONS These results indicate that abnormal TFEB expression is a key mechanism of lysosomal dyshomeostasis caused by protein overload in PTECs. TFEB is thus a potential therapeutic target for the treatment of urinary protein-related kidney disease.
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Affiliation(s)
- Xiaoyu Li
- Institute of Nephrology, and Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Ting Zou
- Institute of Nephrology, and Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Shujun Wang
- Institute of Nephrology, and Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Hongluan Wu
- Institute of Nephrology, and Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Man Wu
- Institute of Nephrology, and Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Zejian Liu
- Institute of Nephrology, and Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
| | - Huafeng Liu
- Institute of Nephrology, and Key Laboratory of Prevention and Management of Chronic Kidney Disease of Zhanjiang City, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China
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Fathallah-Shaykh SA. Proteinuria and progression of pediatric chronic kidney disease: lessons from recent clinical studies. Pediatr Nephrol 2017; 32:743-751. [PMID: 27350622 DOI: 10.1007/s00467-016-3448-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 12/29/2022]
Abstract
Proteinuria in children with chronic kidney disease (CKD) is common and its etiology differs from that in adults. How proteinuria influences the rate of progression of CKD has been analyzed in multiple retrospective clinical studies and more recently in a few prospective ones. In this review I summarize the results, strengths and weaknesses of each of these studies. The findings of several retrospective studies in children with CKD have confirmed what we have learned from adult studies on the association between proteinuria and worsening kidney function. Larger prospective clinical studies have examined the effects of proteinuria on the rate of decline of kidney function and the risk of end-stage kidney disease. They have also considered children with glomerular and, more importantly, the more common, congenital causes of CKD. Current studies have important strengths but also a few weaknesses that limit the validity of the conclusions which can be drawn. There is still a need for large clinical trials that focus primarily on studying the influence of proteinuria on kidney function and on finding remedies that delay progression.
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Affiliation(s)
- Sahar A Fathallah-Shaykh
- Department of Pediatrics, Division of Nephrology, University of Alabama at Birmingham, 516 Lowder Building, 1600 7th Avenue South, Birmingham, AL, 35233, USA.
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Fathallah-Shaykh SA, Flynn JT, Pierce CB, Abraham AG, Blydt-Hansen TD, Massengill SF, Moxey-Mims MM, Warady BA, Furth SL, Wong CS. Progression of pediatric CKD of nonglomerular origin in the CKiD cohort. Clin J Am Soc Nephrol 2015; 10:571-7. [PMID: 25635034 DOI: 10.2215/cjn.07480714] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 01/05/2015] [Indexed: 12/30/2022]
Abstract
BACKGROUND AND OBJECTIVES Congenital anomalies of the kidney and urinary tract and genetic disorders cause most cases of CKD in children. This study evaluated the relationships between baseline proteinuria and BP and longitudinal changes in GFR in children with these nonglomerular causes of CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Urine protein-to-creatinine ratio, casual systolic and diastolic BP (normalized for age, sex, and height), and GFR decline were assessed in the prospective CKD in Children cohort study. RESULTS A total of 522 children, median age 10 years (interquartile range, 7, 14 years) with nonglomerular CKD were followed for a median of 4.4 years. The mean baseline GFR in the cohort was 52 ml/min per 1.73 m(2) (95% confidence interval [95% CI], 50 to 54) and declined 1.3 ml/min per 1.73 m(2) per year on average (95%CI, 1.6 to 1.1). A 2-fold higher baseline urine protein-to-creatinine ratio was associated with an accelerated GFR decline of 0.3 ml/min per 1.73 m(2) per year (95% CI, 0.4 to 0.1). A 1-unit higher baseline systolic BP z-score was associated with an additional GFR decline of 0.4 ml/min per 1.73 m(2) per year (95% CI, 0.7 to 0.1). Among normotensive children, larger GFR declines were associated with larger baseline urine protein-to-creatinine ratios; eGFR declines of 0.8 and 1.8 ml/min per 1.73 m(2) per year were associated with urine protein-to-creatinine ratio <0.5 and ≥0.5 mg/mg, respectively. Among children with elevated BP, average GFR declines were evident but were not larger in children with higher levels of proteinuria. CONCLUSIONS Baseline proteinuria and systolic BP levels are independently associated with CKD progression in children with nonglomerular CKD.
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Affiliation(s)
- Sahar A Fathallah-Shaykh
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
| | - Joseph T Flynn
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Christopher B Pierce
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Alison G Abraham
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Tom D Blydt-Hansen
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Susan F Massengill
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Marva M Moxey-Mims
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Bradley A Warady
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Susan L Furth
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Craig S Wong
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
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Moll S, Meier M, Formentini I, Pomposiello S, Prunotto M. New renal drug development to face chronic renal disease. Expert Opin Drug Discov 2014; 9:1471-85. [DOI: 10.1517/17460441.2014.956075] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Cerqueira DC, Soares CM, Silva VR, Magalhães JO, Barcelos IP, Duarte MG, Pinheiro SV, Colosimo EA, Simões e Silva AC, Oliveira EA. A predictive model of progression of CKD to ESRD in a predialysis pediatric interdisciplinary program. Clin J Am Soc Nephrol 2014; 9:728-35. [PMID: 24458086 DOI: 10.2215/cjn.06630613] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES The incidence of ESRD in children has increased over the last two decades. Nevertheless, there are still limited data on risk factors related to the emergence of ESRD among patients with CKD. The aim of this study was to develop a model of prediction of ESRD in children and adolescents with CKD (stages 2-4) enrolled in a predialysis interdisciplinary management program. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In this retrospective cohort study, 147 patients with CKD admitted from 1990 to 2008 were systematically followed up at a tertiary pediatric nephrology unit for a median of about 4.5 years. The primary outcome was the progression to CKD stage 5. A predictive model was developed using Cox proportional hazards model and evaluated by c statistics. RESULTS The median renal survival was estimated at 98.7 months (95% confidence interval [95% CI], 68.7 to 129.6 months). The probability of reaching CKD stage 5 was estimated as 52% in 10 years. The most accurate model included eGFR, proteinuria at admission, and primary renal disease. Risk score ranged from 0 to 13 points (median, 4 points). The accuracy of the score applied to the sample was high, with c statistics of 0.865 (95% CI, 0.80 to 0.93) and 0.837 (95% CI, 0.76 to 0.91) at follow-up of 2 and 5 years, respectively. By survival analysis, it was estimated that at 10 years after admission, the probability of renal survival was about 63% for patients in the low-risk group and 43% for the medium-risk group; all patients assigned to the high-risk group had CKD stage 5 (P<0.001). CONCLUSION The predictive model of progression of CKD might contribute to early identification of a subgroup of patients at high risk for accelerated renal failure.
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Affiliation(s)
- Debora C Cerqueira
- Department of Pediatrics, Pediatric Nephrourology Unit,, †Nutrition Division, and, ‡Department of Statistics, National Institute of Science and Technology of Molecular Medicine, Faculty of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil
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Methven S, MacGregor MS. Empiricism or rationalism: how should we measure proteinuria? Ann Clin Biochem 2013; 50:296-300. [DOI: 10.1177/0004563212473283] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Proteinuria is the cardinal sign of renal disease, therefore accurate identification of clinically significant proteinuria is essential to the diagnosis and management of kidney disease. Spot samples are now widely used, namely protein: creatinine ratio (uPCR) and albumin: creatinine ratio (uACR). In this article we review the evidence comparing uPCR and uACR including clinical, laboratory and financial arguments. uPCR has a superior performance to uACR to predict 24-hour total proteinuria, the measurement on which the evidence for interventions in chronic kidney disease is based. Furthermore a retrospective study comparing uPCR and uACR as predictors of renal outcome found comparable performance to predict all-cause mortality, commencement of renal replacement therapy and doubling of serum creatinine. Only uPCR takes account of non-albumin proteinuria which has been shown to have prognostic significance. uACR was been thought to be superior at low levels (where there is less ‘noise’ from physiological urinary proteins), but uPCR has recently been shown to perform well at levels equivalent to <0.5 g/day (and even within the reference range) as a predictor of outcomes. uACR is measured using an immunoassay that may be technically superior, but is not without shortcomings (such as antigen excess) and is 2–10 times more expensive than uPCR. The theories explaining the superiority of albumin are appealing. However, the available comparative data do not seem to support the theory. We cannot explain the disparity, but in science, if the data do not fit the existing theory, then maybe it's time for a new theory.
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Affiliation(s)
- Shona Methven
- School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Mark S MacGregor
- John Stevenson Lynch Renal Unit, University Hospital Crosshouse, Kilmarnock, UK
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Methven S, Traynor JP, Hair MD, St J O'Reilly D, Deighan CJ, MacGregor MS. Stratifying risk in chronic kidney disease: an observational study of UK guidelines for measuring total proteinuria and albuminuria. QJM 2011; 104:663-70. [PMID: 21382924 DOI: 10.1093/qjmed/hcr026] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Proteinuria predicts poor renal and cardiovascular outcomes. Some guidelines recommend measuring proteinuria using albumin:creatinine ratio (ACR), while others recommend total protein:creatinine ratio (TPCR). AIM To compare renal outcomes and mortality in the populations identified by these different recommendations. DESIGN Retrospective longitudinal cohort study. METHODS Baseline ACR and TPCR measurements were obtained from 5586 patients with chronic kidney disease (CKD) attending a Scottish hospital nephrology clinic. The cohort was divided into three groups with concordant results by ACR and TPCR (no proteinuria; low proteinuria; significant proteinuria) and one group with discordant results (significant proteinuria with TPCR, but not ACR). Outcomes were assessed using Kaplan-Meier plots and Cox proportional hazards models. RESULTS Median follow-up was 3.5 years [interquartile range (IQR) 2.1-6.0]; 844 (15%) died at 3.0 years (IQR 1.8-4.7) and 468 (8%) started renal replacement therapy (RRT) at 1.7 years (IQR 0.6-3.4). Proteinuria was associated with a substantially increased risk of RRT and death. Patients with significant proteinuria by TPCR, but not ACR (n = 231) had high renal risk, and the highest all-cause mortality (log-rank P < 0.001). With multivariate analysis the risk fell below those with significant proteinuria with concordant results by ACR and TPCR but remained considerably higher than those without significant proteinuria. CONCLUSION Proteinuria screening with TPCR identifies an additional 16% of patients with significant proteinuria, not identified using ACR. This subgroup has high renal risk, and high risk of all-cause mortality and therefore warrant identification. Guideline recommendations on proteinuria screening in CKD should be reconsidered.
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Affiliation(s)
- S Methven
- Specialty Registrar in Nephrology and Clinical Teaching Fellow, John Stevenson Lynch Renal Unit, Crosshouse Hospital, Kilmarnock, KA2 0BE, UK.
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Halbesma N, Jansen DF, Heymans MW, Stolk RP, de Jong PE, Gansevoort RT. Development and Validation of a General Population Renal Risk Score. Clin J Am Soc Nephrol 2011; 6:1731-8. [DOI: 10.2215/cjn.08590910] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Methven S, MacGregor MS, Traynor JP, O'Reilly DSJ, Deighan CJ. Assessing proteinuria in chronic kidney disease: protein-creatinine ratio versus albumin-creatinine ratio. Nephrol Dial Transplant 2010; 25:2991-6. [PMID: 20237054 DOI: 10.1093/ndt/gfq140] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Quantification of proteinuria is important in the assessment of chronic kidney disease (CKD). The aim of this study was to investigate the optimal test to identify significant proteinuria. METHODS We retrospectively assessed the relationship between total protein:creatinine ratio (TPCR), albumin:creatinine ratio (ACR) and 24-h urine total protein in 6842 patients with CKD focusing on performance at thresholds of 0.5 and 1 g/day of proteinuria. RESULTS The relationship between ACR and TPCR is non-linear. TPCR is highly correlated with 24-h urine protein (Spearman's rho = 0.91), though ACR also performs well (rho = 0.84). Using receiver-operator characteristic curve analysis, TPCR outperforms ACR at predicting 0.5 g/day [area under the curve (AUC) 0.967 vs 0.951, P < 0.001] and 1 g/day of proteinuria (AUC 0.968 vs 0.947, P = 0.004). A TPCR threshold of 100 mg/mmol had a higher sensitivity (94% vs 79%) but lower specificity (88% vs 95%) than an ACR of 70 mg/mmol to predict 1 g/day of total proteinuria. To achieve comparable sensitivity, the ACR threshold falls to 17.5 mg/mmol, with lower specificity than TPCR (69.8%). Sensitivity of TPCR rose with increasing age, and in females: to achieve 95% sensitivity in a man <49 years, requires a TPCR of 65 mg/mmol, compared to 179 mg/mmol in a woman >79 years. Non-albumin proteinuria was a lower proportion of total proteinuria in patients receiving angiotensin-converting enzyme inhibitors or angiotensin receptor blockade than in those who were not (P < 0.001). CONCLUSIONS TPCR is a more sensitive screening test than ACR to predict clinically relevant proteinuria. The diagnostic performance of both tests varies substantially with age and gender, and should be taken into consideration when interpreting results. Total proteinuria cannot be adequately predicted from ACR, and our results suggest that caution is appropriate before utilizing ACR in patients with non-diabetic CKD.
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Affiliation(s)
- Shona Methven
- John Stevenson Lynch Renal Unit, Crosshouse Hospital, Kilmarnock, UK
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