epidermal-growth-factor and Ureteral-Obstruction

The effects of obstruction on renal function are the consequence of many factors that profoundly alter all components of glomerular function. Besides the acute effects on glomerular filtration rate and tubule function, a chronic obstruction induces tubular and interstitial injury that results from the activation of different pathways. The progression of tubulointerstitial injury leads to chronic renal damage characterized by tubular atrophy, inflammatory cell infiltration, and interstitial fibrosis. Obstructive nephropathy is an evolving disease in which the renal damage continues even after relief of the obstruction. In particular, it has been demonstrated that the time of relief is the most important factor in predicting long-term renal function deterioration. In this setting, the EGF/MCP-1 ratio, urinary NGAL, and urinary KIM-1 are useful early biomarkers of progressive renal damage and could have a potential role in predicting the long-term renal outcome. This minireview summarizes the role of these emerging urinary biomarkers of obstructive nephropathy based on the current understanding of the pathophysiology of renal injury.

Topics: Acute Kidney Injury; Acute-Phase Proteins; Biomarkers; Chemokine CCL2; Epidermal Growth Factor; Glomerular Filtration Rate; Hepatitis A Virus Cellular Receptor 1; Humans; Kidney Diseases; Kidney Tubules; Lipocalin-2; Lipocalins; Membrane Glycoproteins; Proto-Oncogene Proteins; Receptors, Virus; Ureteral Obstruction

This review focuses on recent advances in understanding the factors contributing to obstructive nephropathy, the most important cause of renal failure in children. The major focus is on renal cellular and molecular events, with emphasis on those affecting the developing kidney.. Experiments in the fetal sheep or neonatal rat, mouse, or pig reveal dramatic effects of urinary tract obstruction on renal growth and development. Surgical relief of obstruction can reverse some of the structural and functional deficits, but cannot restore normalcy. Renal tubular apoptosis is a major factor leading to tubular atrophy following unilateral ureteral obstruction. Increased reactive oxygen species, and a renal environment favoring pro-apoptotic, over survival, signals, contribute to cell death. A variety of intrarenal factors lead to progressive interstitial fibrosis, including the newly described process of epithelial-mesenchymal transition, whereby tubular epithelial cells are transformed into activated fibroblasts. A number of endogenous antifibrotic counter-regulatory molecules have been identified, opening the possibility of enhancing the kidney's own defenses against progressive fibrosis.. The renal response to urinary tract obstruction is complex and involves a wide array of interacting molecules. Elucidation of these interactions will lead to the identification of biomarkers that will allow a more precise prediction to the response to surgical intervention and, hopefully, to novel therapies to prevent renal deterioration.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Calcium-Calmodulin-Dependent Protein Kinases; Connective Tissue Growth Factor; Death-Associated Protein Kinases; Disease Progression; Epidermal Growth Factor; Humans; Immediate-Early Proteins; Inflammation Mediators; Intercellular Signaling Peptides and Proteins; Kidney; Kidney Diseases; Kidney Tubules; Ureteral Obstruction

Obstructive nephropathy is a major cause of renal failure, particularly in infants and children. Cellular and molecular mechanisms responsible for the progression of the tubular atrophy and interstitial fibrosis-processes that lead to nephron loss-have been elucidated in the past 5 years. Following urinary tract obstruction and tubular dilatation, a cascade of events results in upregulation of the intrarenal renin-angiotensin system, tubular apoptosis and macrophage infiltration of the interstitium. This is followed by accumulation of interstitial fibroblasts through proliferation of resident fibroblasts and epithelial-mesenchymal transformation of renal tubular cells. Under the influence of cytokines, chemokines and other signaling molecules produced by tubular and interstitial cells, fibroblasts undergo transformation to myofibroblasts that induce expansion of the extracellular matrix. The cellular interactions that regulate development of interstitial inflammation, tubular apoptosis and interstitial fibrosis are complex. Changes in renal gene expression and protein production afford many potential biomarkers of disease progression and targets for therapeutic manipulation. These include signaling molecules and receptors involved in macrophage recruitment and proliferation, tubular death signals and survival factors, and modulators of epithelial-mesenchymal transformation. Targeted gene deletion and various forms of gene therapy have been used in experimental obstructive nephropathy, mostly rodent models of unilateral ureteral obstruction or cell culture techniques. Further refinement of these models is needed to develop a matrix of biomarkers with clinical predictive value, as well as molecular therapies that will prevent or reverse the renal structural and functional consequences of obstructive nephropathy.

Topics: Apoptosis; Biomarkers; Chemokine CCL7; Epidermal Growth Factor; Fibrosis; Genetic Therapy; Humans; Inflammation; Kidney; Monocyte Chemoattractant Proteins; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Ureteral Obstruction

Obstructive nephropathy is one of the most important causes of renal failure in infants and children, while polycystic kidney disease (PKD) is a major cause of renal failure in the adult population. This review summarizes the evidence that there may be a number of mechanisms common to the pathophysiology of both conditions. In animal models of obstructive nephropathy and PKD, the renal tubular expression of epidermal growth factor is suppressed, and expression of clusterin is increased, both of which suggest arrested maturation or dedifferentiation of the tubular cell. There is a marked increase in apoptosis of epithelial cells in dilated tubules, associated with an increase in apoptotic stimuli. The renin-angiotensin system is activated in both obstructive nephropathy and PKD, which may contribute to tubular atrophy and interstitial fibrosis, which characterize the progression of both conditions. Focal cystic dilatation of the tubule is found in obstructive nephropathy, while tubular obstruction is present in cystic kidney disease. It is therefore likely that elucidation of the effects of mechanical stretch on renal tubular epithelial cells will contribute to our understanding of both conditions.

Topics: Adult; Animals; Apoptosis; Child, Preschool; Epidermal Growth Factor; Humans; Infant; Kidney Diseases; Kidney Tubules; Polycystic Kidney Diseases; Renin-Angiotensin System; Ureteral Obstruction

Congenital obstructive nephropathy remains one of the most-important causes of renal insufficiency in children. This review focuses on the unique interactions that result from urinary tract obstruction during the period of renal development in the neonatal rodent. Following unilateral ureteral obstruction (UUO), growth of the obstructed kidney is impaired and compensatory growth by the intact opposite kidney is related directly to the duration of obstruction. Development of the renal vasculature is delayed by UUO, and the activity of the intrarenal renin-angiotensin system is enhanced throughout the period of obstruction. Glomerular maturation is also delayed by UUO, and nephrogenesis is permanently impaired. The effects of UUO on the developing tubule are also profound, with a suppression of proliferation, stimulation of apoptosis, and the maintenance of an immature phenotype by tubular epithelial cells. Expression of tubular epidermal growth factor is suppressed and transforming growth factor-beta1 and clusterin are increased. Maturation of interstitial fibroblasts is delayed, with progression of tubular atrophy and interstitial fibrosis resulting in part from continued activation of the renin-angiotensin system and oxygen radicals. Future efforts to prevent the consequences of congenital urinary tract obstruction must account for the dual effects of obstruction: interference with normal renal development and progression of irreversible tubulointerstitial injury.

Topics: Animals; Blood Vessels; Epidermal Growth Factor; Kidney; Kidney Diseases; Renin-Angiotensin System; Ureteral Obstruction

Renal insufficiency as a result of congenital obstructive nephropathy is a consequence of impaired renal growth: chronic unilateral ureteral obstruction (UUO) results in greater injury to the immature kidney than to the adult kidney. The neonatal kidney responds to UUO by marked activation of the renin-angiotensin system, which contributes to severe vasoconstriction and progressive interstitial fibrosis of the obstructed kidney. The latter results in part because of activation of transforming growth factor-beta 1 by angiotensin II. Chronic UUO in the neonatal rat delays maturation of the obstructed kidney, possibly in part through suppressed expression of epidermal growth factor. In addition to affecting growth factors, UUO stimulates apoptosis in the obstructed kidney, which is quantitatively greater in the neonate than in the adult. In contrast, expression of clusterin, a glycoprotein that may play a protective role in the response to UUO, is greater in the adult than in the neonatal obstructed kidney. The response of the developing kidney to UUO is similar in a number of respects to cystic kidney disease. This includes a reduction in epidermal growth factor, and increased apoptosis that may result from suppression of bcl-2, an oncoprotein that inhibits apoptosis. Improved knowledge of the cellular and molecular basis for cystic renal disorders should lead to specific intervention in fetuses and infants with congenital obstructive nephropathy, thereby improving renal growth and development.

Topics: Adult; Age Factors; Angiotensin II; Animals; Animals, Newborn; Apoptosis; Clusterin; Epidermal Growth Factor; Fibrosis; Gene Expression Regulation; Glycoproteins; Growth Substances; Hemodynamics; Humans; Infant; Infant, Newborn; Kidney; Kidney Diseases, Cystic; Mice; Mice, Knockout; Models, Biological; Molecular Chaperones; Proto-Oncogene Proteins c-bcl-2; Rats; Renin-Angiotensin System; Transforming Growth Factor beta; Ureteral Obstruction

This study aimed to assess the urinary concentrations of epidermal growth factor (EGF) and kidney injury molecule 1 (KIM-1) in patients with hydronephrosis.. Neonates with a history of prenatal hydronephrosis were enrolled in three groups. Group 1 included neonates with severe obstruction; group 2 included neonates with milder obstruction; and group 3 included neonates with normal findings on postnatal ultrasonography.. 59 neonates were enrolled. The EGF: Cr and KIM-1: Cr ratios were significantly higher in group 1 than in group 2 (p = 0.016 and 0.015, respectively). The cut-off values were measured as 16.855 (sensitivity 71%, specificity 77%) and 0.4765 (sensitivity 81%, specificity 71%) for EGF:Cr and KIM-1:Cr ratios, respectively. The values were significantly higher in group 1 than in group 2.. Evaluation of the urinary KIM-1:Cr ratio may help identify neonates with severe obstructive hydronephrosis.

Topics: Biomarkers; Epidermal Growth Factor; Female; Hepatitis A Virus Cellular Receptor 1; Humans; Hydronephrosis; Infant; Infant, Newborn; Male; Membrane Glycoproteins; Multicystic Dysplastic Kidney; Receptors, Virus; Severity of Illness Index; Ureteral Obstruction

A delay in the diagnosis and treatment of iatrogenic obstructive ureteral injury is the most important prognostic factor for worse results in terms of lesion repair and renal function recovery. The role of the time of relief in determining the onset of renal failure and arterial hypertension in patients with obstructive ureteral injury was evaluated. In addition, we analyzed the prognostic value of the ratio of urinary epidermal growth factor-to-monocyte chemotactic peptide-1 in predicting long-term renal function deterioration.. A total of 76 patients with obstructive ureteral injury and treated with reconstructive procedures were prospectively enrolled in the study. The ratio of epidermal growth factor-to-monocyte chemotactic peptide-1 was evaluated 4 weeks after the relief of obstruction. After a median followup of 60.8 months, estimated creatinine clearance and (99m)technetium-mercaptoacetyltriglycine scan were evaluated.. Within 2 weeks of the obstructive ureteral injury 36 patients underwent surgery for relief of obstruction while in the remaining 40 patients the surgery was performed after more than 2 weeks. Significant differences between the 2 groups were observed regarding mean mercaptoacetyltriglycine clearance of the obstructed kidney (p <0.0001), estimated creatinine clearance (p <0.001) and ratio of epidermal growth factor-to-monocyte chemotactic peptide-1 (p <0.0001). There was a direct correlation between mercaptoacetyltriglycine clearance and epidermal growth factor-to-monocyte chemotactic peptide-1 (rs = 0.78, p <0.0001). Patients with a time of relief greater than 2 weeks had a higher incidence of postoperative hypertension. On logistic regression the time of relief was the only significant variable predicting renal function deterioration (OR 1.49, p = 0.01).. Patients who experience delayed relief of obstructive ureteral injury have decreased long-term renal function as suggested by the lower values of estimated creatinine clearance and mercaptoacetyltriglycine clearance, and are at risk for hypertension or exacerbation of preexisting hypertension.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Biomarkers; Blood Pressure; Chemokine CCL2; Child; Child, Preschool; Creatine; Disease Progression; Epidermal Growth Factor; Female; Follow-Up Studies; Humans; Hypertension; Male; Middle Aged; Plastic Surgery Procedures; Prognosis; Prospective Studies; Renal Insufficiency; Time Factors; Ureter; Ureteral Obstruction; Urologic Surgical Procedures; Young Adult

Hydronephrosis is diagnosed in 0.5% of all newborns, and ureteropelvic junction obstruction (UPJO) is a common cause. The aim of this study was to test whether specific urinary cytokines can be used as UPJO biomarkers in children with hydronephrosis.. Twenty-eight children referred for pyeloplasty due to UPJO and 13 controls were included in this prospective study. Kidney function was assessed and urine samples collected pre-, peri-, and post-operatively. Urine levels of epidermal growth factor (EGF), monocyte chemotactic peptide-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), interferon-γ-inducible protein-10 (IP-10), and RANTES were measured simultaneously by using a bead-based multiplex sandwich immunoassay.. In hydronephrotic children, preoperative urine levels were significantly increased for EGF (median 7.4 [1.2-60.2] vs. median 4.0 [1.2-13.8] ng/mg creatinine) and MCP-1 (median 136.9 [47.7-545.5] vs. median 80.1 [28.8-149.9] pg/mg creatinine) compared to those of controls. Urine levels of EGF and MCP-1 were identical to controls at the postoperative 1-year follow-up exam.. Urine levels of EGF and MCP-1 were preoperatively increased and postoperatively normalized. This study demonstrates that urine-excreted kidney cytokines may be potential biomarkers of obstruction in children with hydronephrosis.

Topics: Adolescent; Biomarkers; Chemokine CCL2; Chemokine CCL3; Chemokine CCL5; Chemokine CXCL10; Child; Child, Preschool; Epidermal Growth Factor; Female; Humans; Hydronephrosis; Infant; Infant, Newborn; Male; Preoperative Care; Prospective Studies; Ureteral Obstruction

Down-regulation of epidermal growth factor (EGF) in the renal parenchyma has been demonstrated in children who underwent pyeloplasty due to ureteropelvic junction obstruction (UPJO). Urine levels of EGF were confirmed to parallel this finding before and after surgery. The aim of our study was to evaluate the relationship between urinary EGF (uEGF) concentrations and Society of Fetal Urology (SFU) high-grade hydronephrosis in infants presenting unilateral antenatal hydronephrosis (ANH).. This was a prospective study involving 45 infants (33 in the observational group, 12 in the surgical group) who presented with unilateral ANH. Postnatal evaluation included a clinical examination, renal ultrasonography, and voiding cystourethrography. Diuretic renal scans were performed in infants with an initial SFU grade 3 or 4 hydronephrosis or increasing hydronephrosis during follow-up. Pyeloplasty was performed when a well-tempered renogram showed an obstructive drainage curve with a half-life of >20 min and/or an obstructive washout curve pattern during the diuretic phase. We studied the longitudinal changes in SFU hydronephrosis grade and uEGF in each group and compared concentration levels at three time points in both groups. The enzyme-linked immunosorbent assay (ELISA) method was used to measure EGF concentrations in the urine. The results were normalized with urinary creatinine (Cr).. During the first 6 months, from 6 to 12 months, and in the second year of life, median SFU hydronephrosis grade and uEGF levels were 2, 2 (p = 0.015), and 1 (p < 0.01), and 50, 59 (p = 0.015), and 69.5 ng/mg Cr (p < 0.01), respectively, in the observational group. In the first 6 months, preoperatively and at 3-12 months postoperatively, the median SFU hydronephrosis grade and uEGF levels were 4, 4, and 3 (p > 0.05), and 38, 46, (p > 0.05), and 55 ng/mg Cr (p < 0.01), respectively, in the surgical group. uEGF levels in the first 6 months of life were significantly lower in the surgical group than in the observational group (p < 0.01). Patients in the observational group with SFU grade 3-4 hydronephrosis showed higher uEGF levels than those in the surgical group with SFU grade 3-4 in (p = 0.048).. Urinary EGF changes over time are associated with inverse changes in SFU hydronephrosis grade, which suggests a role for uEGF as a predictive marker of worsening hydronephrosis grades in infants with ANH. uEGF in the first 6 months of life may predict the need for surgery in infants with ANH.

Topics: Biomarkers; Case-Control Studies; Child, Preschool; Down-Regulation; Enzyme-Linked Immunosorbent Assay; Epidermal Growth Factor; Female; Humans; Hydronephrosis; Infant; Male; Treatment Outcome; Ureteral Obstruction

We demonstrated down-regulation of epidermal growth factor (EGF) and up-regulation of monocyte chemotactic protein-1 (MCP-1) in the renal parenchyma in children who underwent pyeloplasty for ureteropelvic junction obstruction (UPJO). These findings were paralleled by urinary levels of EGF and MCP-1 before and after surgery. The aim of this study is to evaluate the urinary excretion of these cytokines and β2-microglobulin (β2M) in children with urine flow impairment at the ureteropelvic junction or who underwent pyeloplasty.. Seventy-six patients with UPJO and 30 normal children (CTRL) were enrolled in the study. The UPJO patients were divided into obstructive (12), functional (36), and operated (28). Epidermal growth factor, MCP-1, and β2M urinary levels were measured by enzyme-linked immunosorbent assay and normalized to urine creatinine.. Urinary β2M and MCP-1 increased significantly in the UPJO groups compared with the CTRL and significantly improved in the operated group. The obstructive group displayed reduced EGF excretion compared with the CTRL group. The urinary (u)EGF/uMCP-1, and uEGF/uβ2M ratios significantly decreased in both untreated groups. In the operated group, these ratios improved significantly.. The present study substantiates the role of urinary EGF, MCP-1, and β2M as markers of tubulointerstitial damage in human obstructive nephropathy. Furthermore, it suggests that surgical intervention is effective in the management of children with UPJO.

Topics: Adolescent; beta 2-Microglobulin; Biomarkers; Chemokine CCL2; Child; Child, Preschool; Epidermal Growth Factor; Female; Gene Expression Regulation; Humans; Infant; Infant, Newborn; Kidney Pelvis; Kidney Tubules, Proximal; Male; Postoperative Period; Ureter; Ureteral Obstruction

To investigate the effects of long-term epidermal growth factor (EGF) treatment on kidney growth, renal blood flow (RBF), AQP2 expression and urine output in newborn rats with partial unilateral ureteral obstruction (PUUO).. PUUO (n = 29) and sham-operated control (CON) (n = 26) was created in 2-day-old rats. Fifteen PUUO and 14 CON rats were treated with EGF beginning from the second day after operation to 8 weeks of age. Total kidney volume (TKV) and RBF were measured by MRI at weeks 4 and 8, respectively. Urine volume and osmolality, plasma osmolality, and free water clearance were measured. Renal AQP2 expression was determined using semiquantitative immuno-blotting.. PUUO induced a severe hydronephrosis and RBF reduction in the obstructed kidney which was attenuated in EGF-treated rats. Body weight, urine output and free water clearance increased, osmolality and the osmolar clearance decreased significantly in EGF-treated rats, despite unchanged AQP2 levels.. Long-term EGF treatment attenuated the obstruction- induced RBF reduction. Body weight, urine output increased, and urine osmolality decreased in both control and PUUO rats treated with EGF. Solute-free water clearance increased in PUUO rats which seem to be independent of AQP2 expression.

Topics: Animals; Animals, Newborn; Epidermal Growth Factor; Male; Rats; Rats, Wistar; Renal Circulation; Time Factors; Ureteral Obstruction

Ureteral obstruction leads to increased pressure and inducible nitric oxide synthase (iNOS) expression. This study examined the involvement of epidermal growth factor (EGF) receptor (EGFR), nuclear factor-kappaB (NFkappaB), and signal transducers and activators of transcription 3 (STAT3) in iNOS induction in human proximal tubule (HKC-8) cells in response to pressure or EGF. HKC-8 cells were subjected to 60 mmHg pressure or treated with EGF for 0-36 h. iNOS was more rapidly induced in response to EGF than pressure. The addition of EGFR, NFkappaB, and STAT3 inhibitors significantly suppressed pressure- or EGF-stimulated iNOS mRNA and protein expression. Analysis of the activated states of EGFR, NFkappaB p65, and STAT3 after exposure to both stimuli demonstrated phosphorylation within 2.5 min. Anti-EGF antibody inhibited iNOS induction in pressurized HKC-8 cells, providing evidence that endogenous EGF mediates the response to pressure. In ureteral obstruction, when pressure is elevated, phosphorylated EGFR was detected in the apical surface of the renal tubules, validating the in vitro findings. These data indicate that EGFR, NFkappaB, and STAT3 are required for human iNOS gene induction in response to pressure or EGF, indicating a similar mechanism of activation.

Topics: Atmospheric Pressure; Cell Line; Cells, Cultured; Cytokines; Epidermal Growth Factor; ErbB Receptors; Humans; Kidney Tubules, Proximal; Models, Biological; NF-kappa B; Nitric Oxide Synthase Type II; RNA, Messenger; STAT3 Transcription Factor; Ureteral Obstruction

To investigate the role of transforming growth factor beta(1) (TGF-beta(1)) and epidermal growth factor (EGF) in voided urine for the diagnosis and follow-up of children with pelvi-ureteric junction obstruction (PUJO).. The study included 35 children with unilateral PUJO who had a pyeloplasty, and 30 healthy control children. Urine samples were obtained from the bladders of patients before surgery, and as voided samples at 1, 2, 3, 6, 9 and 12 months after surgery. Bladder urine samples were also collected from all 30 children in the control group. TGF-beta(1) and EGF were then measured in all the urine samples.. The level of bladder TGF-beta(1) before surgery in the patients was significantly higher than that in the healthy control group. A threshold of 190 pg/mg creatinine gave a sensitivity of 100%, a specificity of 80%, a positive predictive value of 85.4%, negative predictive value of 100% and an overall accuracy of 90.8%. Compared with the value before surgery, urinary TGF-beta(1) was significantly lower at 1 year after pyeloplasty. There was no significant difference between the level of EGF before surgery in the patients and that in the control group, and no significant difference in the level of EGF before and after surgery over the follow-up.. We do not recommend using EGF levels in voided urine in the routine diagnosis of children with hydronephrosis. The urinary level of TGF-beta(1) is a useful noninvasive tool for the long-term follow-up of children with PUJO treated by pyeloplasty. Further studies with various controls are required to confirm the diagnostic accuracy of TGF-beta(1) in children with PUJO.

Topics: Biomarkers; Case-Control Studies; Child; Child, Preschool; Epidermal Growth Factor; Female; Follow-Up Studies; Humans; Infant; Kidney Pelvis; Male; Predictive Value of Tests; Sensitivity and Specificity; Transforming Growth Factor beta1; Ureteral Obstruction

To study the potential role of pelviureteral junction obstruction (PUJO) in causing progressive renal damage in children through the renal expression of epidermal growth factor (EGF) and transforming growth factor-beta1 (TGF-beta1).. The expression of EGF and TGF-beta1 was evaluated in the renal tissues of 25 children with congenital hydronephrosis by immunohistochemistry, in situ hybridization, and reverse transcriptase polymerase chain reaction techniques.. Children with PUJO had a significant increase in TGF-beta1 and a marked reduction in EGF expression compared with controls. The TGF-beta1/glyceraldehyde phosphate dehydrogenase ratio in the hydronephrotic kidney and normal kidney was 0.53 +/- 0.13 and 0.24 +/- 0.10 respectively, and the difference was significant (P = 0.000). The EGF/glyceraldehyde phosphate dehydrogenase ratio in the hydronephrotic kidney and normal kidney was 0.15 +/- 0.06 and 0.55 +/- 0.13, respectively, and the difference was also significant (P = 0.0001). Positive correlations were found between the TGF-beta1 gene and the drainage clearance half-time (r = 0.47; P = 0.018), TGF-beta1 protein and drainage clearance half-time (r = 0.44; P = 0.028), TGF-beta1 gene and histologic grade (r = 0.53; P = 0.006), and TGF-beta1 protein and histologic grade (r = 0.76; P = 0.000). Negative correlations were found between the EGF gene and drainage clearance half-time (r = -0.59; P = 0.002), EGF protein and drainage clearance half-time (r = -0.61; P = 0.001), EGF gene and histologic grade (r = -0.58; P = 0.003), and EGF protein and histologic grade (r = -0.47; P = 0.019).. TGF-beta1 expression was increased and EGF expression was decreased in the renal tissue after clinical PUJO. The alterations of TGF-beta1 and EGF may play a potential role in the pathogenesis of renal damage in PUJO.

Topics: Child, Preschool; Epidermal Growth Factor; Female; Humans; Hydronephrosis; Kidney; Kidney Pelvis; Male; Transforming Growth Factor beta; Transforming Growth Factor beta1; Ureteral Obstruction

To investigate the roles of epidermal growth factor (EGF), basic fibroblast growth factor (bFGF) and insulin growth factor-1 (IGF-1) in the myocyte regeneration of obstructed ureters.. The expression of EGF, bFGF, IGF-1 and proliferation cell nuclear antigen (PCNA) was studied immunohistochemically in 54 female Sprague-Dawley rats.. Tissue damage to the smooth muscle layer in the obstructed ureters was aggravated during the period of obstruction. The expression of EGF, bFGF and IGF-1 in myocytes was detected using the method of concurrent immunohistochemical staining. The expression of EGF, bFGF and IGF-1 in the smooth muscle layer was found from Day 14 after ligation. The expression of EGF, bFGF and IGF-1 increased to a peak on Day 21 and then declined. The expression of PCNA in the smooth muscle layer was also found from Day 14 after ligation and increased to a peak on Day 21. The expressions of EGF, bFGF and IGF-1 were significantly correlated with the expression of PCNA in the smooth muscle layer (r=0.7982, 0.6264 and 0.5840, respectively; p-values all <0.002). Co-expression of EGF, bFGF, IGF-1 and PCNA was determined using the method of double immunofluorescence staining. Co-expression of PCNA was observed in 34% of EGF-positive myocytes, 53.6% of bFGF-positive myocytes and 41.1% of IGF-1-positive myocytes at Day 21 post-ligation.. Expression of EGF, bFGF and IGF-1 may contribute to myocyte regeneration of damaged ureters in rats with obstructive uropathy.

Topics: Animals; Epidermal Growth Factor; Female; Fibroblast Growth Factor 2; Fluorescent Antibody Technique; Immunohistochemistry; Insulin-Like Growth Factor I; Myocytes, Smooth Muscle; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Regeneration; Time Factors; Ureteral Obstruction

Exogenous growth factors administered during unilateral ureteral obstruction (UUO) in neonatal rats significantly reduce apoptosis and tubular atrophy. Because the mechanism underlying these salutary effects is largely unknown, we investigated signaling pathways potentially activated by growth factors to determine their roles in therapeutic action.. Mechanical strain was applied to confluent cultures of immortalized rat proximal tubule cells to simulate obstruction-induced stretch injury in vivo. Growth factors, inhibitory antibodies or pharmacological inhibitors were added to cultures that were subsequently processed for TUNEL analysis or immunoblots to identify signaling pathways that could be modulating cell survival. For in vivo studies, kidneys harvested from rats +/- UUO +/- epidermal growth factor (EGF) were fixed or frozen for immunohistochemistry or immunoblot analysis.. Treatment with EGF or insulin-like growth factor-1 (IGF-1) during stretch decreased apoptosis by 50% (P < 0.001). Neutralizing antibodies (Abs) directed against either growth factor or its receptor blocked the reduction in apoptosis. Stretch decreased BAD phosphorylation by approximately 50% (P < 0.001) relative to unstretched cells and each growth factor restored phosphorylation to basal levels. Kinase-specific inhibitors that blocked growth factor-mediated BAD phosphorylation promoted apoptosis in vitro. BAD phosphorylation decreased by approximately 50% (P < 0.001) in the tubules of obstructed hydronephrotic rat kidneys and administration of EGF restored BAD phosphorylation to basal levels.. Signaling pathways converging at BAD phosphorylation are key to growth factor-mediated attenuation of stretch-induced apoptosis in vitro and in vivo.

Topics: Animals; Apoptosis; bcl-Associated Death Protein; Carrier Proteins; Cell Line, Transformed; Epidermal Growth Factor; Hydrostatic Pressure; In Vitro Techniques; Kidney Tubules, Proximal; Phosphorylation; Rats; Signal Transduction; Somatomedins; Ureteral Obstruction

The aim of this study was to test the hypothesis that expression of epidermal growth factor (EGF) and transforming growth factor-beta 1 (TGF-beta 1) may be altered in stenotic tissue of patients with congenital hydronephrosis caused by pelviureteric junction (PUJ) obstruction and to evaluate the role of these 2 growth factors.. The expression of EGF and TGF-beta 1 was evaluated in tissue specimens in 25 children with PUJ obstruction and 15 controls with normal PUJs by immunohistochemistry, in situ hybridization, and reverse transcriptase polymerase chain reaction (RT-PCR) techniques. All the signals of mRNA products were normalized to the mRNA levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) a housekeeping gene, as a ratio.. On RT-PCR study, the amount of TGF-beta 1 mRNA in stenotic tissue was higher than in controls, in addition, EGF gene expression in the obstructed junction was significantly lower than in normal junctions. The TGF-beta 1 to GAPDH ratio was 0.57 +/- 0.26 and 0.36 +/- 0.19 in the stenotic tissue and the normal ureter, respectively (P =.012). The EGF to GAPDH ratio was 0.17 +/- 0.08 and 0.37 +/- 0.14 in the stenotic tissue and the normal ureter, respectively (P =.0001). Furthermore, the positive correlations were found between TGF-beta1 gene and protein expression (r = 0.601; P =.001), TGF-beta 1 gene and drainage clearance half-time (T1/2) (r = 0.474; P =.017), TGF-beta 1 protein expression, and T1/2 (r = 0.516; P =.008). A negative correlation was found between EGF gene and T1/2 (r = -0.448; P =.025). On immunolabeling and in situ hybridization labeling, the expression of TGF-beta 1 protein was strongly positive and confined to the muscle cells, spindle cells, and collagen fibers in the stenotic tissue; the expression of TGF-beta 1 mRNA was moderately positive and mainly distributed in the collagen of the stenotic segment, both the expression of EGF protein and mRNA were negative in the normal ureter.. There were increased TGF-beta 1 mRNA expression and decreased EGF mRNA expression in the stenotic tissue after clinical ureteropelvic junction obstruction. The alteration of EGF and TGF-beta 1 expression may be involved in the pathogenesis of congenital hydronephrosis.

Topics: Child; Child, Preschool; Constriction, Pathologic; Epidermal Growth Factor; Female; Gene Expression Regulation; Genetics; Humans; Hydronephrosis; In Situ Hybridization; Kidney; Kidney Pelvis; Male; Radionuclide Imaging; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta; Transforming Growth Factor beta1; Ureter; Ureteral Obstruction

Tubulointerstitial inflammation and fibrosis are pathologic hallmarks of end-stage renal disease (ESRD). Here we have used DNA microarray technology to monitor the transcriptomic responses to murine unilateral ureteral obstruction (UUO) with a view to identifying molecular modulators of tubulointerstitial fibrosis.. Using Affymetrix Mu74Av2 microarrays, gene expression 4 and 10 days postobstruction was investigated relative to control contralateral kidneys. Candidate profibrogenic genes were further investigated in epithelial cells undergoing epithelial to mesenchymal transition (EMT) in vitro.. mRNA levels for 1091 gene/EST sequences, of a total of 12,488 displayed on the microarray, were altered twofold or greater by days 4 and 10 postobstruction compared to contralateral control kidneys. Genes were categorised into functional groups, including modulators of cytoskeletal and extracellular matrix metabolism, cell growth, signalling, and transcription/translational events. Among the potentially profibrogenic genes, whose mRNA levels were increased after UUO, were fibroblast-inducible secreted protein (fisp-12), the murine homologue of connective tissue growth factor (CTGF), collagen XVIIIalpha1, secreted protein acidic and rich in cysteine (SPARC), and src-suppressed C-kinase substrate (SSeCKS). A sustained increase in fisp-12 mRNA level was observed during EMT induced by transforming growth factor-beta1 (TGF-beta1) and epidermal growth factor (EGF).. Altered gene expression in murine UUO has been demonstrated. Increased expression of fisp-12, SPARC, and SSeCKS has been shown in response to TGF-beta1 treatment and during EMT, suggesting that these genes may offer potential therapeutic targets against tubulointerstitial fibrosis.

Topics: A Kinase Anchor Proteins; Animals; Cell Cycle Proteins; Cells, Cultured; Collagen Type XVIII; Connective Tissue Growth Factor; Disease Progression; Epidermal Growth Factor; Gene Expression; Immediate-Early Proteins; Intercellular Signaling Peptides and Proteins; Mice; Mice, Inbred C57BL; Mitogens; Oligonucleotide Array Sequence Analysis; Osteonectin; Protein Isoforms; RNA, Messenger; Transforming Growth Factor beta; Transforming Growth Factor beta1; Ureteral Obstruction

The expression of certain growth factors in the epidermal growth factor (EGF) family is altered in response to renal injury. Recent studies have demonstrated that heparin binding EGF-like growth factor (HB-EGF) expression may be cytoprotective in response to apoptotic signals. The purpose of this study was to investigate the potential role of HB-EGF in the upper urinary tract following unilateral ureteral obstruction. We present evidence that: i) ureteral obstruction induced cell-specific but transient activation of HB-EGF gene expression; ii) HB-EGF expression in renal epithelial cells increased under conditions where mechanical deformation, such as that caused by hydronephrotic distension, induces apoptosis, but HB-EGF expression did not increase in renal pelvis smooth muscle cells under identical conditions; and iii) enforced expression of HB-EGF served to protect renal epithelial cells from stretch-induced apoptosis. These results suggest a potential mechanism by which the kidney protects itself from apoptosis triggered by urinary tract obstruction.

Topics: Actins; Animals; Apoptosis; Cells, Cultured; Disease Models, Animal; DNA Fragmentation; DNA Primers; Epidermal Growth Factor; Epithelial Cells; Female; gamma-Glutamyltransferase; Heparin-binding EGF-like Growth Factor; Humans; Immunoenzyme Techniques; Intercellular Signaling Peptides and Proteins; Keratins; Kidney Cortex; Leucyl Aminopeptidase; Mice; Muscle, Smooth; Rats; Rats, Zucker; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transfection; Up-Regulation; Ureteral Obstruction

Obstructive nephropathy is characterized at the histologic level by tubular atrophy and interstitial monocyte infiltration. The molecular mechanisms underlying these histologic changes are still poorly defined. Epidermal growth factor (EGF) produced by tubular cells seems to play a pivotal role in the modulation of tubular cell growth, while monocyte chemotactic peptide-1 (MCP-1) is a powerful and specific chemotactic and activating factor for monocytes.. Twenty-four patients with congenital ureteropelvic junction obstruction [UPJO; 10 with recurrent urinary tract infection (UTI) and 10 with no UTI] and 15 healthy children were studied. Diagnosis was made by renal ultrasound, intravenous pielography, and MAG3 scan. Urinary samples were collected before and after surgery. In 10 patients, urine was also collected directly from the affected pelvis at the time of surgery. Urinary EGF and MCP-1 levels were measured by enzyme-linked immunosorbent assay. MCP-1 and EGF gene expression were evaluated by in situ hybridization in 15 biopsies from congenital UPJO and in 10 normal kidneys.. In normal kidneys, there was a high expression of EGF mRNA, whereas MCP-1 mRNA was undetectable. MCP-1 gene expression was strikingly increased at the tubulointerstitial level in UPJO biopsies compared with controls and was directly correlated with the extent of monocyte infiltration. In addition, UPJO kidney sections showed a marked reduction in EGF gene expression that was directly correlated with the degree of tubular damage. EGF urine concentration was significantly reduced in UPJO when compared with control and directly correlated with its renal gene expression. On the other hand, the MCP-1 urine concentration was strikingly increased in UPJO patients. It is noteworthy that a significant and inverse correlation was observed between the MCP-1 concentration in the urine collected from the obstructed pelvis and the MAG3 clearance of the obstructed kidney (r = -0.76). The presence of recurrent UTI was associated with a significantly higher MCP-1 excretion and a slight reduction in EGF urine concentration. The surgical correction of UPJO was followed by an improvement of renal function together with a significant reduction in MCP-1 excretion and a marked increase in EGF urine concentrations. Interestingly, EGF urine concentration measured before surgery was significantly correlated with the difference between the MAG3 clearance of the obstructed kidney before and after surgery.. MCP-1 and EGF seem to be involved in the pathogenesis of tubulointerstitial damage in congenital obstructive nephropathy, and their urine excretion may represent a powerful prognostic marker in this form of renal disease.

Topics: Adolescent; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Biomarkers; Chemokine CCL2; Child; Child, Preschool; Enzyme-Linked Immunosorbent Assay; Epidermal Growth Factor; Female; Gene Expression; Humans; In Situ Hybridization; Infant; Infant, Newborn; Male; Monocytes; Prognosis; Radioisotope Renography; RNA, Messenger; Ureteral Obstruction

Obstructive nephropathy is a primary cause of renal insufficiency in infants and children. This study was designed to distinguish the reversible and irreversible cellular consequences of temporary unilateral ureteral obstruction (UUO) on the developing kidney.. Rats were subjected to UUO or sham operation in the first 48 hours of life, and the obstruction was removed five days later (or was left in place). Kidneys were removed for study 14 or 28 days later. In additional groups, kidneys were removed at the end of five days of obstruction. Immunoreactive distribution of renin was determined in arterioles, and the distribution of epidermal growth factor, transforming growth factor-beta1, clusterin, vimentin, and alpha-smooth muscle actin was determined in tubules and/or interstitium. The number of glomeruli, glomerular maturation, tubular atrophy, and interstitial collagen deposition was determined by morphometry. Renal cellular proliferation and apoptosis were measured by proliferating cell nuclear antigen and the TdT uridine-nick-end-label technique, respectively. The glomerular filtration rate was measured by inulin clearance.. Renal microvascular renin maintained a fetal distribution with persistent UUO; this was partially reversed by the relief of obstruction. Although glomerular maturation was also delayed and glomerular volume was reduced by UUO, the relief of obstruction prevented the reduction in glomerular volume. Although relief of obstruction did not reverse a 40% reduction in the number of nephrons, the glomerular filtration rate of the postobstructed kidney was normal. The relief of obstruction did not improve tubular cell proliferation and only partially reduced apoptosis induced by UUO. This was associated with a persistent reduction in the tubular epidermal growth factor. In addition, the relief of obstruction reduced but did not normalize tubular expression of transforming growth factor-beta1, clusterin, and vimentin, all of which are evidence of persistent tubular injury. The relief of obstruction significantly reduced interstitial fibrosis and expression of alpha-smooth muscle actin by interstitial fibroblasts, but not to normal levels.. The relief of obstruction in the neonatal rat attenuates, but does not reverse, renal vascular, glomerular, tubular, and interstitial injury resulting from five days of UUO. Hyperfiltration by remaining nephrons and residual tubulointerstitial injury in the postobstructed kidney are likely to lead to deterioration of renal function later in life.

Topics: Actins; Animals; Animals, Newborn; Child; Clusterin; Disease Models, Animal; Epidermal Growth Factor; Glomerular Filtration Rate; Glycoproteins; Humans; Infant; Kidney Failure, Chronic; Kidney Glomerulus; Kidney Tubules; Molecular Chaperones; Rats; Rats, Sprague-Dawley; Renin; Time Factors; Transforming Growth Factor beta; Ureteral Obstruction; Vimentin

Inhibition of angiotensin action, pharmacologically or genetically, during the neonatal period leads to renal anomalies involving hypoplastic papilla and dilated calyx. Recently, we documented that angiotensinogen (Agt -/-) or angiotensin type 1 receptor nullizygotes (Agtr1 -/-) do not develop renal pelvis nor ureteral peristaltic movement, both of which are essential for isolating the kidney from the high downstream ureteral pressure. We therefore examined whether these renal anomalies could be characterized as "obstructive" nephropathy.. Agtr1 -/- neonatal mice were compared with wild-type neonates, the latter subjected to surgical complete unilateral ureteral ligation (UUO), by analyzing morphometrical, immunohistochemical, and molecular indices. Agtr1 -/- mice were also subjected to a complete UUO and were compared with wild-type UUO mice by quantitative analysis. To assess the function of the urinary tract, baseline pelvic and ureteral pressures were measured.. The structural anomalies were qualitatively indistinguishable between the Agtr1 -/- without surgical obstruction versus the wild type with complete UUO. Thus, in both kidneys, the calyx was enlarged, whereas the papilla was atrophic; tubulointerstitial cells underwent proliferation and also apoptosis. Both were also characterized by interstitial macrophage infiltration and fibrosis, and within the local lesion, transforming growth factor-beta 1, platelet-derived growth factor-A and insulin-like growth factor-1 were up-regulated, whereas epidermal growth factor was down-regulated. Moreover, quantitative differences that exist between mutant kidneys without surgical obstruction and wild-type kidneys with surgical UUO were abolished when both underwent the same complete surgical UUO. The hydraulic baseline pressure was always lower in the pelvis than that in the ureter in the wild type, whereas this pressure gradient was reversed in the mutant.. The abnormal kidney structure that develops in neonates during angiotensin inhibition is attributed largely to "functional obstruction" of the urinary tract caused by the defective development of peristaltic machinery.

Topics: Actins; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Angiotensinogen; Animals; Animals, Newborn; Apoptosis; Cell Division; Disease Models, Animal; Epidermal Growth Factor; Gene Expression Regulation, Developmental; In Situ Hybridization; In Situ Nick-End Labeling; Insulin-Like Growth Factor I; Kidney Diseases; Kidney Medulla; Kidney Pelvis; Macrophages; Mice; Mice, Knockout; Muscle, Smooth; Peptidyl-Dipeptidase A; Platelet-Derived Growth Factor; Pressure; RNA, Messenger; Transforming Growth Factor beta; Ureter; Ureteral Obstruction

Renal epidermal growth factor (EGF) is suppressed by unilateral ureteral obstruction (UUO), and we reported previously that exogenous EGF attenuates renal injury due to UUO in the neonatal rat. In this study, we wished to determine whether administration of epidermal growth factor (EGF) improves long-term renal cellular recovery after relief of obstruction.. One ureter of 1 day-old rats was occluded or sham-operated, and rats received daily injections of EGF, 0.1 mg./kg., or saline for the following 7 days. Five days following UUO, the obstruction was removed. Kidneys were removed 28 days following release of UUO or sham operation, and processed for histomorphometry and immunohistochemistry.. Kidney weight and the number of glomeruli were reduced in the postobstructed kidney regardless of administration of EGF. However, EGF reduced tubular vimentin by 36% and clusterin expression by 70% (markers of tubular injury), and decreased tubular atrophy by 50% in the postobstructed kidney compared with saline-treated rats. EGF also reduced interstitial alpha-smooth muscle actin and interstitial collagen deposition by 50% in the postobstructed kidney.. Short-term administration of EGF markedly attenuates both tubular and interstitial injury one month following the release of UUO in the neonatal rat. This suggests therapeutic potential for targeted delivery of growth factors to optimize recovery after release of urinary tract obstruction.

Topics: Animals; Animals, Newborn; Epidermal Growth Factor; Kidney; Rats; Rats, Sprague-Dawley; Ureteral Obstruction

Little is known about the mechanisms underlying recovery from hydronephrosis. Using a rat kidney model, we investigated the possible contribution of growth factors during regeneration after hydronephrosis.. After the unilateral ureteral obstruction for 7 days, the obstruction was released by ureterocystostomy. Epidermal growth factor (EGF), hepatocyte growth factor (HGF) and transforming growth factor-beta1 (TGF-beta1) were studied using immunohistochemistry and semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR).. The immunoreaction of EGF in the medulla of both obstructed and contralateral kidneys increased after releasing the obstruction. The release of ureteral obstruction brought further increased immunoreaction of HGF to both the cortex and the medulla of the contralateral kidney. The immunoreaction of TGF-beta1 also increased in the interstitium especially around the blood vessels in the post-obstructed kidney. The expression of HGF and EGF mRNA in both kidneys and TGF-beta1 mRNA in the obstructed kidney were increased after releasing the obstruction.. These results suggest that various growth factors may be involved in the post-obstructive tubular recovery and interstitial damage in the rat kidney.

Topics: Animals; Epidermal Growth Factor; Growth Substances; Hepatocyte Growth Factor; Immunohistochemistry; Kidney; Male; Postoperative Period; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transforming Growth Factor beta; Ureteral Obstruction

Obstructive nephropathy is a primary cause of renal failure in infancy. Chronic unilateral ureteral obstruction (UUO) in the neonatal rat results in reduced renal expression of epidermal growth factor (EGF), renal tubular epithelial (RTE) cell apoptosis and interstitial fibrosis. We wished to determine whether these changes could be prevented by exogenous administration of EGF.. Thirty-three Sprague-Dawley rats underwent UUO within the first 48 hours of life, and received daily injections of either EGF (0.1 mg/kg/day) or saline (control) for the following seven days, after which obstructed and intact opposite kidneys were removed for study. These were compared to 11 sham-operated rats that received either no injections, EGF injections, or saline injections. Renal cell proliferation was determined by proliferating cell nuclear antigen, apoptosis was measured by the TUNEL technique, and the distribution of vimentin, clusterin, transforming growth factor-beta 1 (TGF-beta 1), and alpha-smooth muscle actin were determined by immunohistochemistry. Tubular dilation, tubular atrophy, and interstitial collagen deposition were quantitated by histomorphometry.. Compared to controls, EGF treatment increased RTE cell proliferation in the obstructed kidney by 76%, decreased apoptosis by 80%, and reduced vimentin, clusterin and TGF-beta 1 immunostaining (all P < 0.05). EGF treatment reduced tubular dilation by 50%, atrophic tubules by 30%, and interstitial fibrosis by 50% (all P < 0.05). There was no significant effect of EGF on renal alpha smooth muscle actin distribution. There was no effect of saline or EGF injections on kidneys from sham-operated rats for any of the parameters studied.. We conclude that EGF stimulates RTE cell proliferation and maturation and reduces apoptosis in the neonatal rat kidney subjected to chronic UUO. These effects may contribute to the reduction in tubular dilation, tubular atrophy, and interstitial fibrosis. By preserving renal development, administration of EGF attenuates the renal injury resulting from chronic UUO.

Topics: Animals; Animals, Newborn; Apoptosis; Cell Division; Chronic Disease; Clusterin; Complement Inactivator Proteins; Epidermal Growth Factor; Fibrosis; Glycoproteins; Kidney; Kidney Tubules; Ligation; Molecular Chaperones; Proliferating Cell Nuclear Antigen; Rats; Rats, Sprague-Dawley; Transforming Growth Factor beta; Ureter; Ureteral Obstruction; Urothelium; Vimentin

Acute unilateral ureteral obstruction (UUO) results in ipsilateral hydronephrosis characterized by a decrease in epidermal growth factor (EGF) mRNA expression and EGF protein levels in the distal renal tubules. UUO results in programmed cell death with increases in the characteristic markers of apoptosis. To suppress the apoptotic response during UUO, recombinant EGF was administered during renal obstruction and the ensuing molecular and histologic changes were studied.. Mature Sprague-Dawley rats underwent left ureteral obstruction and the kidneys were harvested at 24, 48, and 72 hours. Markers of apoptosis included DNA laddering pattern on agarose gel electrophoresis, in situ gap labeling of fragmented DNA for quantitative apoptotic body determination, polyadenylated mRNA expression of SGP-2, and in situ hybridization for sulfated glycoprotein-2 (SGP-2) mRNA. Studies were repeated in rats following administration of 10, 20, and 40 micrograms of subcutaneous recombinant EGF on a daily basis after UUO.. Subcutaneous injection of EGF into unilaterally obstructed rats promotes renal tubular epithelial cell regeneration, as demonstrated by increased cortical mitotic activity. Systemic EGF supplementation in these unilaterally obstructed rats also resulted in a decrease in the intensity of the DNA laddering pattern associated with renal tubular apoptosis. An in situ labeling procedure to identify apoptotic nuclei in the ureterally obstructed kidneys revealed a 50% reduction in apoptosis after EGF administration. Northern blot analysis and in situ hybridization for SGP-2 mRNA or clustering gene product also revealed a decreased expression in the obstructed and EGF-treated renal parenchyma.. These data suggest that EGF, apart from its known role as a mitogenic substance for renal tubular epithelial cells, is also a critical in vivo renal cell survival factor for the developmentally mature kidney.

Topics: Animals; Apoptosis; Clusterin; DNA Fragmentation; Epidermal Growth Factor; Glycoproteins; Kidney Tubules; Molecular Chaperones; Rats; Rats, Sprague-Dawley; Ureteral Obstruction

The aim of the present study was to develop a short bioresorbable ureteric stent and to characterize the chosen polymers with respect to surface modification, biocompatibility, and loading of a biologically active compound. As materials for the stent, poly(D,L-lactide) and poly(D,L-lactide-co-glycolide) were chosen. Degradation experiments were carried out and analytical data were obtained by contact angle measurement, X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy in the attenuated reflection mode (FTIR-ATR). Gas loading technology was used to incorporate biologically active compounds, and biocompatibility of the polymers was assessed by in vitro cellular assays, applying measures such as cell morphology, proliferative activity, and membrane integrity. Our results indicate that surface modification of bioresorbable polymers is a suitable and efficient approach to improve the surface properties. Incorporation of biologically active compounds was possible without loss of activity, and in vitro assessment of cellular responses demonstrated the biocompatibility of the chosen polymers and modifications.

Topics: Absorption; Animals; Biocompatible Materials; Biodegradation, Environmental; Cell Adhesion; Cell Division; Epidermal Growth Factor; Humans; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Lactic Acid; Polyesters; Polyglycolic Acid; Polylactic Acid-Polyglycolic Acid Copolymer; Polymers; Prosthesis Design; Spectrometry, X-Ray Emission; Spectroscopy, Fourier Transform Infrared; Stents; Ureteral Obstruction

The purpose of this study was to investigate the role of growth-related peptides in the impairment of renal growth and development resulting from unilateral ureteral obstruction (UUO) in the neonatal rats.. Sprague-Dawley rats underwent UUO or sham-operation in the first 48-hours of life, and kidneys were harvested 1 to 28 days later. Renal messenger RNA (mRNA) was quantitated for renin, transforming growth factor-beta 1 (TGF-beta 1) and epidermal growth factor (EGF). Renal interstitial volume was measured in Masson-trichrome-stained sections, and renin and alpha-smooth muscle actin (alpha-SM actin) distribution were determined by immunocytochemistry.. The normal developmental increase in renal mass and DNA content were suppressed in ipsilateral UUO and increased in the intact opposite kidney. Renal interstitial volume was increased more than 10-fold by ipsilateral UUO. Unilateral ureteral obstruction resulted in a sustained increased in ipsilateral renal renin mRNA and persistence of fetal renin distribution. Renin in the contralateral kidney was suppressed. Transforming growth factor-beta 1 expression increased progressively in the obstructed kidney, but decreased after 7 days in sham-operated kidneys. While renal EGF expression was undetectable in the normal sham kidney during the first 3 days of life, it increased steadily with maturation. However, EGF expression remained suppressed in the obstructed kidney. Whereas alpha-SM actin disappeared from the interstitium of normal rat kidneys by 15 days of age, it persisted in the obstructed neonatal kidney.. As revealed by changes in expression of growth-related peptides, neonatal UUO delays ipsilateral renal development, which may contribute to impaired renal growth.

Topics: Actins; Animals; Animals, Newborn; Chronic Disease; Epidermal Growth Factor; Gene Expression Regulation; Kidney; Rats; Rats, Sprague-Dawley; Renin; RNA, Messenger; Time Factors; Transforming Growth Factor beta; Ureteral Obstruction

Unilateral ureteral obstruction (UUO) in the neonate impairs growth of the ipsilateral kidney. Since renal renin expression is increased by UUO, we hypothesized that, by activation of AT1 receptors, angiotensin II (ANG II) regulates expression of transforming growth factor-beta 1 (TGF-beta 1) and epidermal growth factor (EGF) in the obstructed kidney. Sprague-Dawley rats underwent left UUO or sham operation within the first 48 h of life and received losartan, 40 mg.kg-1.day-1, or saline. After 14 days, steady-state renal mRNA was determined for renin, TGF-beta 1, EGF, and clusterin. Losartan reduced the DNA content of the intact kidneys but did not further decrease that of the obstructed kidney. Losartan increased renal renin expression and decreased EGF expression by 80%, regardless of UUO. In contrast, losartan reduced TGF-beta 1 expression by 34% in obstructed kidneys but did not affect TGF-beta 1 in intact kidneys. Losartan increased clusterin expression by 60% in obstructed kidneys and seven-fold in intact kidneys. We conclude that activation of the ANG II AT1 receptor is necessary for normal renal growth and that TGF-beta 1 is regulated by AT1 receptors in the obstructed, but not intact, kidneys. Through AT1 receptors, endogenous ANG II stimulates EGF and inhibits clusterin expression.

Topics: Angiotensin II; Angiotensin Receptor Antagonists; Animals; Animals, Newborn; Biphenyl Compounds; Blotting, Northern; Clusterin; DNA; Epidermal Growth Factor; Gene Expression; Glyceraldehyde-3-Phosphate Dehydrogenases; Glycoproteins; Imidazoles; Kidney; Losartan; Molecular Chaperones; Nerve Tissue Proteins; Rats; Rats, Sprague-Dawley; Receptors, Angiotensin; Reference Values; Renin; RNA, Messenger; Tetrazoles; Transforming Growth Factor beta; Ureteral Obstruction

Partial ureteral obstruction in the weanling rat leads to hydronephrosis of the ipsilateral kidney and renal cell deletion through the process of programmed cell death known as apoptosis. The apoptotic response following partial ureteral obstruction in weanling Sprague-Dawley rats was studied using the traditional markers of apoptosis, including deoxyribonucleic acid (DNA) laddering pattern on agarose gel electrophoresis, in situ gap labeling of fragmented DNA for quantitative apoptotic body determination, polyadenylated messenger ribonucleic acid (mRNA) expression of sulfated glycoprotein-2, and polyadenylated mRNA expression of epidermal growth factor and transforming growth factor-beta. Partial ureteral obstruction resulted in a progressive increase in the intensity of DNA fragmentation associated with apoptosis during the initial 3 weeks. Quantitative apoptotic body counting revealed a 3-fold increase by week 3 of partial obstruction. This increase represented a level of apoptosis, which is 65% of that observed in complete ureteral obstruction. By week 2 of partial obstruction there was a 13-fold increase in the expression of sulfated glycoprotein-2 mRNA, as well as changes in the growth factor environment characterized by a decline in the constitutive expression of epidermal growth factor mRNA and an increase in the expression of transforming growth factor-beta mRNA. These altered levels represent changes in expression comparable to those observed during the apoptotic response following complete ureteral obstruction, although the time course is delayed by 2 to 3 weeks.

Topics: Animals; Apoptosis; Blotting, Northern; Clusterin; DNA; Electrophoresis, Agar Gel; Epidermal Growth Factor; Glycoproteins; Hydronephrosis; Kidney Tubules; Molecular Chaperones; Rats; Rats, Sprague-Dawley; RNA, Messenger; Transforming Growth Factor beta; Ureteral Obstruction

Northern and dot-blot analysis of polyadenylated RNAs of kidney cortical and outer medullary tissue was performed in male Sprague-Dawley rats at varying times up to 24 hours after bilateral ureteral obstruction (BUO), after 24 hours of unilateral obstruction (UUO) and at varying periods after release of BUO or UUO. Pre-proEGF (preproEGF) and Tamm-Horsfall (TH) mRNA declined by four hours of BUO to virtually undetectable levels at 24 hours of ureteral obstruction. Upon release of BUO or UUO, preproEGF and TH mRNA returned slowly toward normal but remained below control levels up to four days after release of ureteral obstruction. Urinary EGF excretion paralleled these changes in renal preproEGF mRNA. Although these changes are similar to those observed during nephrotoxic and ischemic renal failure, where the expression of the immediate early genes precedes the fall in preproEGF and TH expression, no such increase in the expression of these genes occurred after bilateral ureteral obstruction. These changes in preproEGF and TH expression could also be dissociated from uremia and high rates of DNA synthesis, suggesting that ureteral obstruction itself is a sufficient cause of the reduced expression. The increase in ureteral pressure and its functional and humoral effects may each play a role in reduced preproEGF and TH expression during ureteral obstruction.

Topics: Acute Kidney Injury; Animals; DNA; Epidermal Growth Factor; Gene Expression; Kidney; Male; Mucoproteins; Protein Precursors; Rats; Rats, Inbred Strains; RNA, Messenger; Ureteral Obstruction; Uromodulin

Unilateral ureteral obstruction in the rat leads to hydronephrosis of the affected kidney and renal cell deletion through the process of apoptosis. We studied this experimental model to determine whether acute alterations in renal growth factor expression might be involved in the initiation of the apoptotic response. Northern blot analysis of hydronephrotic, contralateral and sham operated kidney polyadenylated messenger ribonucleic acid (mRNA) was performed to quantitate the expression of mRNA encoding the growth factors epidermal growth factor, transforming growth factor-beta and insulin-like growth factor II during the first 48 hours following ureteral obstruction. Although the expression of the insulin-like growth factor II mRNA was unchanged by ureteral obstruction, the expression of epidermal growth factor mRNA rapidly declined in the obstructed kidney during this period. The loss of epidermal growth factor expression was further confirmed by an immunocytochemical staining procedure that demonstrated high concentrations of epidermal growth factor in control renal tubules and a drastic loss of this staining in obstructed renal tubules. In contrast, expression of transforming growth factor-beta mRNA increased in the obstructed kidney. We believe that the altered growth factor environment of the hydronephrotic kidney might be an initiating factor in the onset of renal apoptosis associated with this condition.

Topics: Animals; Blotting, Northern; Epidermal Growth Factor; Growth Substances; Hydronephrosis; Immunohistochemistry; Insulin-Like Growth Factor II; Kidney; Rats; Rats, Inbred Strains; RNA, Messenger; Transforming Growth Factor beta; Ureteral Obstruction