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Galvão RLDF, Meneses GC, Pinheiro MCC, Martins AMC, Daher EDF, Bezerra FSM. Kidney injury biomarkers and parasitic loads of Schistosoma mansoni in a highly endemic area in northeastern Brazil. Acta Trop 2022; 228:106311. [PMID: 35038425 DOI: 10.1016/j.actatropica.2022.106311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 12/21/2021] [Accepted: 01/12/2022] [Indexed: 01/20/2023]
Abstract
Schistosomiasis affects approximately 240 million people worldwide. In Brazil, it is estimated that 1.5 million people are infected with Schistosoma mansoni and up to 15% of diagnosed individuals develop kidney damage. Renal involvement in schistosomiasis mansoni is characterized by glomerular lesions, with a high incidence, especially in chronically infected patients living in areas of high endemicity. Renal damage occurs slowly and is often asymptomatic, with a long-term manifestation of chronic kidney disease, with progressive loss of kidney functions, and early detection of subclinical kidney disease is of great importance. The aim of this study was to investigate kidney damage in patients infected with S. mansoni through urinary biomarkers of kidney injury and their association with the different parasite loads found. The patients were divided into two groups based on the diagnosis of infection by S. mansoni by the Kato-Katz and IgG-ELISA-SEA method: group of individuals infected by S. mansoni, Kato-Katz positive (PG); and group of individuals not infected by S. mansoni, Kato-Katz-negative (NG). Urinary creatinine and albuminuria were determined by immunoturbidimetry and proteinuria by the colorimetric method. The urinary biomarkers of podocyte injury (VEGF and Nephrin) and glomerular inflammation (MCP-1) were quantified by immunoassay and expressed by the urinary creatinine ratio. Urinary VEGF showed significantly higher levels in PG compared to NG (p = 0.004), increasing at all intensities of infection including low parasite load (p = 0.020). Our results show increased signs of podocyte damage in patients with schistosomiasis mansoni regardless of the parasite load, evidenced by increased urinary VEGF levels. However, further studies are needed since data related to schistosomiasis glomerulopathy and its association with new urinary biomarkers of kidney injury are scarce in the literature.
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Valério FC, Lemos RD, de C Reis AL, Pimenta LP, Vieira ÉL, Silva ACE. Biomarkers in vesicoureteral reflux: an overview. Biomark Med 2020; 14:683-696. [PMID: 32643393 DOI: 10.2217/bmm-2019-0378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Aim: This article aimed to review the role of cytokines, chemokines, growth factors and cellular adhesion molecules as biomarkers for vesicoureteral reflux (VUR) and reflux nephropathy (RN). Methods: We reviewed articles from 1979 onward by searching PubMed and Scopus utilizing the combination of words: 'VUR' or 'RN' and each one of the biomarkers. Results: Genetic, inflammatory, fibrogenic, environmental and epigenetic factors responsible for renal scarring need to be better understood. TGF-β, IL-10, IL-6, IL-8 and TNF seem to exert a role in VUR particularly in RN based on the current literature. Serum levels of procalcitonin have been also associated with high-grade VUR and RN. These molecules should be more intensively evaluated as potential biomarkers for renal scarring in VUR. Conclusion: Further studies are necessary to define which molecules will really be of utility in clinical decisions and as therapeutic targets for VUR and RN.
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Affiliation(s)
- Flávia C Valério
- Laboratório Interdisciplinar de Investigação Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais (UFMG), Brazil.,Pediatric Nephrology Unit, Hospital das Clínicas, UFMG, Belo Horizonte, MG, Brazil
| | - Renata D Lemos
- Laboratório Interdisciplinar de Investigação Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Ana L de C Reis
- Laboratório Interdisciplinar de Investigação Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Letícia P Pimenta
- Laboratório Interdisciplinar de Investigação Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Érica Lm Vieira
- Laboratório Interdisciplinar de Investigação Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais (UFMG), Brazil
| | - Ana Cs E Silva
- Laboratório Interdisciplinar de Investigação Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais (UFMG), Brazil.,Pediatric Nephrology Unit, Hospital das Clínicas, UFMG, Belo Horizonte, MG, Brazil
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Miyakita H, Hayashi Y, Mitsui T, Okawada M, Kinoshita Y, Kimata T, Koikawa Y, Sakai K, Satoh H, Tokunaga M, Naitoh Y, Niimura F, Matsuoka H, Mizuno K, Kaneko K, Kubota M. Guidelines for the medical management of pediatric vesicoureteral reflux. Int J Urol 2020; 27:480-490. [PMID: 32239562 PMCID: PMC7318347 DOI: 10.1111/iju.14223] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/10/2020] [Indexed: 12/27/2022]
Abstract
Urinary tract infection is a bacterial infection that commonly occurs in children. Vesicoureteral reflux is a major underlying precursor condition of urinary tract infection, and an important disorder in the field of pediatric urology. Vesicoureteral reflux is sometimes diagnosed postnatally in infants with fetal hydronephrosis diagnosed antenatally. Opinions vary regarding the diagnosis and treatment of vesicoureteral reflux, and diagnostic procedures remain debatable. In terms of medical interventions, options include either follow‐up observation in the hope of possible spontaneous resolution of vesicoureteral reflux with growth/development or provision of continuous antibiotic prophylaxis based on patient characteristics (age, presence/absence of febrile urinary tract infection, lower urinary tract dysfunction and constipation). Furthermore, there are various surgical procedures with different indications and rationales. These guidelines, formulated and issued by the Japanese Society of Pediatric Urology to assist medical management of pediatric vesicoureteral reflux, cover the following: epidemiology, clinical practice algorithm for vesicoureteral reflux, syndromes (dysuria with vesicoureteral reflux, and bladder and rectal dysfunction with vesicoureteral reflux), diagnosis, treatment (medical and surgical), secondary vesicoureteral reflux, long‐term prognosis and reflux nephropathy. They also provide the definition of bladder and bowel dysfunction, previously unavailable despite their close association with vesicoureteral reflux, and show the usefulness of diagnostic tests, continuous antibiotic prophylaxis and surgical intervention using site markings.
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Affiliation(s)
- Hideshi Miyakita
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Urology, Tokai University Oiso Hospital, Oiso, Kanagawa, Japan
| | - Yutaro Hayashi
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Pediatric Urology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Takahiko Mitsui
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Urology, University of Yamanashi Graduate School of Medical Sciences, Chuo, Yamanashi, Japan
| | - Manabu Okawada
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Pediatric General and Urogenital Surgery, Juntendo University Hospital, Tokyo, Japan
| | - Yoshiaki Kinoshita
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Pediatric Surgery, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Takahisa Kimata
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Pediatrics, Kansai Medical University, Hirakata, Osaka, Japan
| | - Yasuhiro Koikawa
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Urology, Fukuoka City Medical Center of Sick Children, Fukuoka, Japan
| | - Kiyohide Sakai
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Urology, Miyagi Children's Hospital, Sendai, Miyagi, Japan
| | - Hiroyuki Satoh
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Urology and Kidney Transplantation, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Masatoshi Tokunaga
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Urology, Tokai University Oiso Hospital, Oiso, Kanagawa, Japan
| | - Yasuyuki Naitoh
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Fumio Niimura
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Pediatrics, Tokai University School of Medicine, Hiratsuka, Kanagawa, Japan
| | - Hirofumi Matsuoka
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Urology, Faculty of Medicine, Fukuoka University, Fukuoka, Japan
| | - Kentaro Mizuno
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Pediatric Urology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Kazunari Kaneko
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Pediatrics, Kansai Medical University, Hirakata, Osaka, Japan
| | - Masayuki Kubota
- Committee for the Formulation of Medical Management Guidelines for Pediatric Vesicoureteral Reflex, Japanese Society of Pediatric Urology, Osaka, Japan.,Department of Pediatric Surgery, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
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Urinary biomarkers of latent inflammation and fibrosis in children with vesicoureteral reflux. Int Urol Nephrol 2019; 52:603-610. [PMID: 31832877 DOI: 10.1007/s11255-019-02357-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 12/05/2019] [Indexed: 12/28/2022]
Abstract
PURPOSE To investigate the urinary levels of TGF-β1, VEGF, and MCP-1 as potential biomarkers of latent inflammation and fibrosis in the kidney before and 6 months after correction of vesicoureteral reflux (VUR) in children. METHODS A total of 88 patients (mean age 26 months) with VUR were divided into three groups: group A-patients with grades II-III VUR, conservative treatment; group B-patients with grades III-V VUR, endoscopic correction of VUR; group C-patients with grades III-V VUR, ureteral reimplantation after failed endoscopic correction. Control group included 20 healthy children. Biomarker levels were measured by ELISA. 99mTc-DMSA scintigraphy and renal histology were performed if possible. RESULTS At admission, TGF-β1 was close to control in all study groups, VEGF increased with severity of the disease, and MCP-1 increased in group C. Six months after correction of VUR, despite clinical and laboratory improvement, TGF-β1 and MCP-1 increased while VEGF decreased compared to the admission values in all groups; no amelioration of renal scarring was detected either by 99mTc-DMSA scintigraphy or renal histology. CONCLUSION The results support our hypothesis that successful correction of VUR is not sufficient to stop or reduce the latent inflammatory and fibrotic processes that have already started in the kidney regardless of the reflux grade and treatment option. Measuring the urinary levels of TGF-β1, VEGF, and MCP-1 may aid in the development of non-invasive, pathophysiologically relevant approach to diagnosis and monitoring of kidney injury and fibrosis in children with VUR.
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Anigilaje EA. A Putative Role of Apolipoprotein L1 Polymorphism in Renal Parenchymal Scarring Following Febrile Urinary Tract Infection in Nigerian Under-Five Children: Proposal for a Case-Control Association Study. JMIR Res Protoc 2018; 7:e156. [PMID: 29903699 PMCID: PMC6024104 DOI: 10.2196/resprot.9514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 03/23/2018] [Accepted: 04/10/2018] [Indexed: 01/13/2023] Open
Abstract
Background Although urinary tract infection (UTI) resolves with prompt treatment in a majority of children, some children, especially those aged less than 5 years, also develop renal parenchymal scarring (RPS). RPS causes high blood pressure that may lead to severe chronic kidney disease and end-stage renal disease (ESRD). Although the risk of UTI is higher in white children than in black children, it is unknown whether RPS is more common in white children than in black children as data are scarce in this regard. A common genetic predisposition to kidney disease in African Americans and the sub-Saharan African blacks is the possession of apolipoprotein L1 (APOL1). APOL1 risk variants regulate the production of APOL1. APOL1 circulates in the blood, and it is also found in the kidney tissue. While circulating, APOL1 kills the trypanosome parasites; an increased APOL1 in kidney tissues, under the right environmental conditions, can also result in the death of kidney tissue (vascular endothelium, the podocytes, proximal tubules, and arterial cells), which, ultimately, is replaced by fibrous tissue. APOL1 may influence the development of RPS, as evidence affirms that its expression is increased in kidney tissue following UTI caused by bacteria. Thus, UTI may be a putative environmental risk factor responsible for APOL1-induced kidney injury. Objective The aim of this proposal was to outline a study that seeks to determine if the possession of two copies of either G1 or G2 APOL1 variant increases the risk of having RPS, 6 months following a febrile UTI among Nigerian under-five children. Methods This case-control association study seeks to determine whether the risk of RPS from febrile UTI is conditional on having 2 APOL1 risk alleles (either G1 or G2). Cases will be children with a confirmed RPS following a febrile UTI. Controls will be age-, gender-, and ethnic-matched children with a febrile UTI but without RPS. Children with vesicoureteral reflux and other congenital anomalies of the urinary tract are to be excluded. Association between predictor variables (ethnicity, APOL1 G1 or G2, and others) and RPS will be tested at bivariate logistic regression analyses. Predictors that attained significance at a P value of ˂.05 will be considered for multiple logistic regressions. Likelihood-based tests will be used for hypothesis testing. Estimation will be done for the effect size for each of the APOL1 haplotypes using a generalized linear model. Results The study is expected to last for 3 years. Conclusions The study is contingent on having a platform for undergoing a research-based PhD program in any willing university in Europe or elsewhere. The findings of this study will be used to improve the care of African children who may develop RPS following febrile UTI. Registered Report Identifier RR1-10.2196/9514
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Affiliation(s)
- Emmanuel Ademola Anigilaje
- Nephrology Unit, Department of Paediatrics, College of Health Sciences, University of Abuja, Abuja, Nigeria
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Bimpaki E, Bitsori M, Choulaki C, Galanakis E. Vascular endothelial growth factor-A gene polymorphism is associated with congenital renal lesions in children with urinary tract infections. Acta Paediatr 2017; 106:1348-1353. [PMID: 28471482 DOI: 10.1111/apa.13897] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/17/2017] [Accepted: 04/28/2017] [Indexed: 12/01/2022]
Abstract
AIM This study investigated the relationship between vascular endothelial growth factor-A (VEGF-A)-460C/T functional gene polymorphism and renal parenchymal lesions, vesicoureteral reflux and other urinary tract abnormalities in children with a urinary tract infection (UTI). METHODS VEGF-A-460C/T gene polymorphism was investigated with restriction length polymorphism analysis in 76 children with their first UTI and in 63 controls without infections. Genotype and allele frequencies were compared between children with UTIs and controls and between different groups with UTIs. RESULTS The VEGF-A-460C/T genotype frequencies differed significantly between those with and without renal parenchymal lesions in the UTI cohort. Allele C homozygosity was significantly more common in those with renal parenchymal lesions (36.6% versus 8.7%, p = 0.007). A separate analysis showed that allele C was associated with lesions compatible with hypodysplasia, rather than with focal ones associated with infections, with an odds ratio of 11.55 and 95% confidence interval of 3.03-43.9 (p = 0.0001). No significant differences in genotypes or allele frequencies were found between children with and without reflux or other urinary tract anomalies. CONCLUSION In children with UTIs, C allele polymorphism of the VEGF-A gene was associated with hypodysplastic renal parenchymal lesions, which were possibly congenital and existed before the infection.
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Affiliation(s)
- Eirini Bimpaki
- Department of Paediatrics, Heraklion University Hospital, Heraklion, Greece
| | - Maria Bitsori
- Department of Paediatrics, Heraklion University Hospital, Heraklion, Greece
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Yim HE, Bae IS, Yoo KH, Hong YS, Lee JW. Genetic control of VEGF and TGF-beta1 gene polymorphisms in childhood urinary tract infection and vesicoureteral reflux. Pediatr Res 2007; 62:183-7. [PMID: 17597658 DOI: 10.1203/pdr.0b013e31809871f1] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We investigated whether genetic polymorphisms of vascular endothelial growth factor (VEGF) and transforming growth factor-beta1 (TGF-beta1), potential candidate genes in the pathogenesis of urinary tract infection (UTI) and vesicoureteral reflux (VUR), are associated with the susceptibility to UTI and VUR, and renal scarring. We recruited 89 controls and 86 UTI and 58 VUR children. The UTI group was subdivided into two groups according to renal scarring. Two polymorphisms of VEGF and three of TGF-beta1 genes were investigated by using PCR-restriction fragment length polymorphism analysis. In both UTI and VUR groups, there was an increase in frequency of the VEGF -460 CC (control, 4.3; UTI, 15.9; VUR, 17.8%; p < 0.05), TGF-beta1 -509 CC (control, 8.7; UTI, 34.6; VUR, 35.1%; p < 0.001), and TGF-beta1 -800 GG genotypes (control, 19.1; UTI, 40.5; VUR, 40.4%; p < 0.05). An increase in the TGF-beta1 +869 CC (scar-positive, 35.4; scar-negative, 10.3%; p < 0.05) and a decrease in the +869 TC genotype (scar-positive, 29.2; scar-negative, 55.2%; p < 0.05) were observed in the scar-positive subjects. There were no differences in +405 VEGF genotype frequencies. The VEGF T-460C and the TGF-beta1 C-509T, G-800A, and T869C polymorphisms could be genetic markers of the process of UTI and VUR.
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Affiliation(s)
- Hyung Eun Yim
- Department of Pediatrics, College of Medicine, Korea University, Seoul, 152-703, Korea
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Lindenmeyer MT, Kretzler M, Boucherot A, Berra S, Yasuda Y, Henger A, Eichinger F, Gaiser S, Schmid H, Rastaldi MP, Schrier RW, Schlöndorff D, Cohen CD. Interstitial vascular rarefaction and reduced VEGF-A expression in human diabetic nephropathy. J Am Soc Nephrol 2007; 18:1765-76. [PMID: 17475821 DOI: 10.1681/asn.2006121304] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Diabetic nephropathy (DN) is a frequent complication in patients with diabetes. Although the majority of DN models and human studies have focused on glomeruli, tubulointerstitial damage is a major feature of DN and an important predictor of renal dysfunction. This study sought to investigate molecular markers of pathogenic pathways in the renal interstitium of patients with DN. Microdissected tubulointerstitial compartments from biopsies with established DN and control kidneys were subjected to expression profiling. Analysis of candidate genes, potentially involved in DN on the basis of common hypotheses, identified 49 genes with significantly altered expression levels in established DN in comparison with controls. In contrast to some rodent models, the growth factors vascular endothelial growth factor A (VEGF-A) and epidermal growth factor (EGF) showed a decrease in mRNA expression in DN. This was validated on an independent cohort of patients with DN by real-time reverse transcriptase-PCR. Immunohistochemical staining for VEGF-A and EGF also showed a reduced expression in DN. The decrease of renal VEGF-A expression was associated with a reduction in peritubular capillary densities shown by platelet-endothelial cell adhesion molecule-1/CD31 staining. Furthermore, a significant inverse correlation between VEGF-A and proteinuria, as well as EGF and proteinuria, and a positive correlation between VEGF-A and hypoxia-inducible factor-1alpha mRNA was found. Thus, in human DN, a decrease of VEGF-A, rather than the reported increase as described in some rodent models, may contribute to the progressive disease. These findings and the questions about rodent models in DN raise a note of caution regarding the proposal to inhibit VEGF-A to prevent progression of DN.
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Affiliation(s)
- Maja T Lindenmeyer
- Nephrologisches Zentrum, Medizinische Poliklinik, University of Munich, Pettenkoferstrasse 8a, 80336 Munich, Germany
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Wilkinson L, Gilbert T, Kinna G, Ruta LA, Pennisi D, Kett M, Little MH. Crim1KST264/KST264Mice Implicate Crim1 in the Regulation of Vascular Endothelial Growth Factor-A Activity during Glomerular Vascular Development. J Am Soc Nephrol 2007; 18:1697-708. [PMID: 17460146 DOI: 10.1681/asn.2006091012] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Crim1, a transmembrane cysteine-rich repeat-containing protein that is related to chordin, plays a role in the tethering of growth factors at the cell surface. Crim1 is expressed in the developing kidney; in parietal cells, podocytes, and mesangial cells of the glomerulus; and in pericytes that surround the arterial vasculature. A gene-trap mouse line with an insertion in the Crim1 gene (Crim1(KST264/KST264)) displayed perinatal lethality with defects in multiple organ systems. This study further analyzed the defects that are present within the kidneys of these mice. Crim1(KST264/KST264) mice displayed abnormal glomerular development, illustrated by enlarged capillary loops, podocyte effacement, and mesangiolysis. When outbred, homozygotes that reached birth displayed podocyte and glomerular endothelial cell defects and marked albuminuria. The podocytic co-expression of Crim1 with vascular endothelial growth factor-A (VEGF-A) suggested a role for Crim1 in the regulation of VEGF-A action. Crim1 and VEGF-A were shown to interact directly, providing evidence that cysteine-rich repeat-containing proteins can bind to non-TGF-beta superfamily ligands. Crim1(KST264/KST264) mice display a mislocalization of VEGF-A within the developing glomerulus, as assessed by immunogold electron microscopy and increased activation of VEGF receptor 2 (Flk1) in the glomerular endothelial cells, suggesting that Crim1 regulates the delivery of VEGF-A by the podocytes to the endothelial cells. This is the first in vivo demonstration of regulation of VEGF-A delivery and supports the hypothesis that Crim1 functions to regulate the release of growth factors from the cell of synthesis.
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Affiliation(s)
- Lorine Wilkinson
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia 4072
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