epidermal-growth-factor and Diabetic-Nephropathies

Foot ulcers affect 15% of patients with diabetes, resulting in a great health burden. The occurrence and development of diabetic foot ulcers is associated with neuropathy, peripheral arterial disease, and infection. Several growth factors are involved in these processes, including epidermal growth factor, vascular endothelial growth factor, transforming growth factor-beta, fibroblast growth factor, and erythropoietin, which could promote wound healing of patients with diabetes. Thus, this review discusses the role of these growth factors in the pathogenesis of diabetic foot ulcers, aiming to achieve novel insights into the management of diabetic foot ulcers.

Topics: Diabetic Foot; Diabetic Nephropathies; Epidermal Growth Factor; Erythropoietin; Humans; Intercellular Signaling Peptides and Proteins; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A; Wound Healing

Glucose is a key fuel and an important metabolic substrate in mammals. Renal proximal tubular cells (PTCs) not only reabsorb filtered glucose but are also believed to play a role in the glucotoxicity associated with renal pathogenesis, such as in diabetes. The proximal tubule environment is where 90% of the filtered glucose is reabsorbed by the low-affinity/high-capacity Na(+)/glucose cotransporter 2 (SGLT2) and facilitated diffusion glucose transporter 2 (GLUT2). Both active and facilitative glucose transporters have distinct distribution profiles along the proximal tubule related to their particular kinetic characteristics. A number of mechanisms contribute to the changes in the cellular functions, which occur in response to exposure to various endogenous factors. Hyperglycemia was reported to regulate the renal SGLT activities through the reactive oxygen species-nuclear factor-kappaB pathways, which suggests that the transcellular glucose uptake within the PTCs contribute to the development of diabetic-like nephropathy. Angiotensin II (ANG II) plays an important role in its development through epidermal growth factor receptor (EGFR) transactivation. Therefore, a combination of high glucose, ANG II, and EGF are involved in diabetic-like nephropathy by regulating the SGLT activity. In addition, endogenously enhanced SGLTs have a cytoprotective function. The renal proximal tubules play a major role in regulating the plasma glucose levels, and there is increasing interest in the renal glucose transporters on account of their potential implications in the treatment of various conditions including diabetes mellitus.

Topics: Angiotensin II; Animals; Diabetic Nephropathies; Dogs; Epidermal Growth Factor; ErbB Receptors; Glucose; Humans; Hyperglycemia; Kidney Tubules, Proximal; Mice; Rabbits; Rats; Sodium-Glucose Transport Proteins

Nephrogenesis is controlled by a sequence of inductive signals between different areas of the developing kidney. As these signals are being elucidated, it has become clear that many important developmental genes are re-expressed in the mature organ following injury, possibly as part of repair and regeneration. While this reuse of developmental pathways may contribute to healing and repair, it may alternatively result in scar formation if specific components of the pathways are missing, if the temporal correlation of various elements is faulty, or if an injurious stimulus persists. In the review we will use diabetic nephropathy as an example to illustrate this paradigm in renal disease. The pathogenesis of diabetic nephropathy is complex and characterized by altered expression of many genes, including growth factors, apoptotic regulators, cellular matrix components, and cytoskeletal proteins. Many of these factors also function during kidney development. The elucidation of the roles these genes play in nephrogenesis and of their array of molecular partners and modulators may ultimately shed light on the pathogenesis of disease (and indeed vice versa), and may even suggest new therapeutic strategies.

Topics: Animals; Bone Morphogenetic Protein 7; Bone Morphogenetic Proteins; Connective Tissue Growth Factor; Diabetic Nephropathies; Endothelial Growth Factors; Epidermal Growth Factor; Humans; Immediate-Early Proteins; Intercellular Signaling Peptides and Proteins; Kidney; Lymphokines; Matrix Metalloproteinases; Proteins; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

The development of diabetic nephropathy in patients with Type I (insulin-dependent) and Type II (non-insulin-dependent) diabetes mellitus is still a huge clinical problem associated with increased morbidity and mortality. The mechanisms underlying the development of diabetic kidney disease are extremely complex and yet not completely understood. Among many potential pathogenic mechanisms responsible for the development of diabetic kidney disease, various growth factors have been suggested to be important players. In particular, growth hormone (GH)/insulin-like growth factors (IGFs), transforming growth factor beta (TGF-beta), vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) have measurable effects on the development of experimental diabetic kidney disease through complex intra-renal systems. Recent findings that these growth factors might initiate the early diabetic renal changes have provided insight into processes that might be relevant for future development of new drugs useful in the treatment of diabetic kidney disease. As will appear from the present review, enhanced understanding of the cellular mechanisms responsible for the development of diabetic kidney disease has already allowed the design of specific antagonists of pathophysiologically increased growth factors. Recent studies have shown that treating experimental diabetic models with such antagonists is followed by renoprotection.

Topics: Animals; Cytokines; Diabetic Nephropathies; Endothelial Growth Factors; Epidermal Growth Factor; Growth Hormone; Growth Substances; Humans; Lymphokines; Somatomedins; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Diabetes mellitus is associated with typical patterns of long term vascular complications which vary with the organ involved. The microvascular kidney disease (Olgemoller and Schleicher, 1993) is characterized by thickening of the capillary basement membranes and increased deposition of extracellular matrix components (ECM), while loss of microvessels with subsequent neovascularisation is predominant in the eye and peripheral nerves. On the other hand macrovascular disease is characterized by accelerated atherosclerosis. These complications are dependent on long term hyperglycemia. Specific biochemical pathways linking hyperglycaemia to microvascular changes were proposed: the polyol pathway (Greene et al., 1987), non-enzymatic glycation of proteins (Brownlee et al., 1988), glucose autooxidation and oxidative stress (Hunt et al., 1990), hyperglycemic pseudohypoxia (Williamson et al., 1993) enhanced activation of protein kinase C by de novo-synthesis of diacyl glycerol (Lee et al., 1989; DeRubertis and Craven 1994) and others. These pathways are not mutually exclusive (Larkins and Dunlop, 1992; Pfeiffer and Schatz, 1992). They may be linked to alterations in the synthesis of growth factors particularly since atherosclerosis and angioneogenesis are associated with increased proliferation of endothelial and smooth muscle cells. Increased synthesis of ECM components is stimulated by growth factors like transforming growth factor beta (TGF beta) (Derynck et al., 1984) and insulin-like growth factor I (IGF-I) (Moran et al., 1991). This review will summarize some of the recent evidence for an involvement of growth factors in diabetic vascular complications and will attempt to assign their emergence in the sequence of events leading to vascular complications.

Topics: Animals; Arteriosclerosis; Diabetic Angiopathies; Diabetic Nephropathies; Diabetic Retinopathy; Epidermal Growth Factor; Fibroblast Growth Factor 2; Growth Hormone; Growth Substances; Humans; Hyperglycemia; Insulin Resistance; Insulin-Like Growth Factor I; Receptors, Somatotropin; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

The current study aims to understand the mechanisms behind regulated cell death (RCD) in diabetic nephropathy and identify related biomarkers through bioinformatics and experimental validation. Datasets of bulk and single-cell RNA sequencing were obtained from public databases and analyzed using gene set variation analysis (GSVA) with gene sets related to RCD, including autophagy, necroptosis, pyroptosis, apoptosis, and ferroptosis. RCD-related gene biomarkers were identified using weighted gene correlation network analysis (WGCNA). The results were verified through experiments with an independent cohort and

Topics: Adaptor Proteins, Signal Transducing; Biomarkers; Diabetes Mellitus; Diabetic Nephropathies; Epidermal Growth Factor; Humans; Membrane Proteins; Necroptosis; Regulated Cell Death

Diabetic nephropathy (DN) is a prevalent and debilitating disease that represents the leading cause of chronic kidney disease which imposes public health challenges Tongmai Jiangtang capsule (TMJT) is commonly used for the treatment of DN, albeit its underlying mechanisms of action are still elusive.. This study retrieved databases to identify the components and collect the targets of TMJT and DN. Target networks were constructed to screen the core components and targets. Samples from the GEO database were utilized to perform analyses of targets and immune cells and obtain significantly differentially expressed core genes (SDECGs). We also selected a machine learning model to screen the feature genes and construct a nomogram. Furthermore, molecular docking, another GEO dataset, and Mendelian randomization (MR) were utilized for preliminary validation. We subsequently clustered the samples based on SDECG expression and consensus clustering and performed analyses between the clusters. Finally, we scored the SDECG score and analyzed the differences between clusters.. This study identified 13 SDECGs between DN and normal groups which positively regulated immune cells. We also identified five feature genes (. TMJT may alleviate DN via core components (e.g. Denudatin B, hancinol, hirudinoidine A) targeting SDECGs (e.g. SRC, EGF, GAPDH), with the involvement of feature genes and modulation of immune and inflammation-related pathways. These findings have potential implications for clinical practice and future investigations.

Topics: Cluster Analysis; Databases, Factual; Diabetes Mellitus; Diabetic Nephropathies; Epidermal Growth Factor; Humans; Molecular Docking Simulation

Kidney biopsies of patients with diabetic nephropathy (DN) and normal kidney function may exhibit interstitial fibrosis (IF) without reduction of glomerular filtration rate (GFR) because of hyperfiltration. The aim of our study was to analyse the performance of a set of biomarkers of tubular injury to estimate the extent of IF in patients with DN and normal kidney function.. This cross-sectional study included 118 adults with DN diagnosed by kidney biopsy and GFR ≥90 mL/min/1.73 m2 and a control group of healthy subjects. We measured the urinary excretion of monocyte chemoattractant protein-1 (MCP-1) neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), liver-type fatty acid-binding protein (L-FABP), β2-microglobulin and dickkopf-3 protein (DKK-3) at the time of kidney biopsy. GFR was measured by chromium-51 labeled ethylenediamine tetraacetic acid (Cr-EDTA) (measured GFR). IF was quantified using a quantitative morphometric procedure. Predictive multivariate models were developed to estimate the IF surface.. Patients with DN showed significantly higher levels of DKK-3, MCP-1 and L-FABP and significantly lower levels of epidermal growth factor (EGF) than healthy controls. There were no significant between-group differences in the levels of β2-microglobulin, KIM-1 or NGAL. IF was negatively associated with EGF and positively with age, proteinuria, MCP-1, DKK-3 and L-FABP, but not with β2-microglobulin, KIM-1, NGAL or GFR. The best model to predict IF surface accounted for 59% of its variability and included age, proteinuria, EGF, DKK-3 and MCP-1.. Our study provides a model to estimate the IF in DN that can be useful to assess the progression of IF in patients with normal kidney function.

Topics: Adult; Biomarkers; Chemokine CCL2; Cross-Sectional Studies; Diabetes Mellitus; Diabetic Nephropathies; Edetic Acid; Epidermal Growth Factor; Fatty Acid-Binding Proteins; Fibrosis; Glomerular Filtration Rate; Humans; Kidney; Lipocalin-2; Proteinuria

Topics: Albuminuria; Angiopoietin-1; Angiopoietin-2; Animals; Diabetes Mellitus; Diabetic Nephropathies; Epidermal Growth Factor; Mice; Mice, Obese; Protein-Tyrosine Kinases

Micro-albuminuria is considered an early clinical sign of diabetes nephropathy, however, early decrease of glomerular filtration can be present years before the presence of microalbuminuria. In this study, we explored whether urinary epidermal growth factor (uEGF) might serve as an early marker of diabetes nephropathy compared to microalbuminuria in children and adolescents.. Children with type 1 diabetes mellitus (n = 158) and healthy controls (n = 40) were included in this study. Serum and urine samples were collected three times with an interval of at least one month to determine creatinine (serum and urine), epidermal growth factor and albumin (urine). Demographic data and routine lab values were extracted out of the electronic patient files.. uEGF was significantly lower in children with T1DM compared to healthy controls (p = 0.032). A relatively lower glomerular filtration rate (eGFR) was associated with a decreased uEGF (p < 0.001). uEGF was independently associated with eGFR in a multivariate analysis.. This study provides evidence that uEGF can serve as an early marker of diabetes nephropathy in children and adolescents.

Topics: Adolescent; Albuminuria; Biomarkers; Child; Creatinine; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Epidermal Growth Factor; Glomerular Filtration Rate; Humans; Kidney

In diabetic kidney disease (DKD), it is important to find biomarkers for predicting initiation and progression of the disease. Besides glomerular damage, kidney tubular injury and inflammation are also involved in the development of DKD. The current study investigated the associations of urinary epidermal growth factor (uEGF), monocyte chemotactic protein-1 (MCP-1) and the uEGF:MCP-1 ratio with kidney involvement in patients at early and advanced stages of DKD.. The concentration of uEGF and uMCP-1 was measured in two Chinese population-based studies. The associations of uEGF, uMCP-1 and uEGF/MCP-1 with occurrence of DKD were studied in a cross-sectional study (n = 1811) of early stage DKD. Associations of baseline uEGF, uMCP-1 and uEGF/MCP-1 with kidney outcome were assessed in a longitudinal cohort (n = 208) of advanced-stage DKD.. In both studies, positive correlations were found between uEGF/urine creatinine (Cr) and estimated glomerular filtration rate (eGFR) at sampling and between uMCP-1/Cr and urinary albumin:creatinine ratio (uACR). In the cross-sectional study, uEGF/Cr and uEGF/MCP-1 were negatively associated with the occurrence of DKD {odds ratio (OR) 0.65 [95% confidence interval (CI) 0.54-0.79], P < 0.001; 0.82 (0.71-0.94), P = 0.005, respectively}. In the longitudinal cohort, the uEGF:MCP-1 ratio correlated more closely with the percentage change of eGFR slope (r = 0.33, P < 0.001) as compared with uEGF/Cr or uMCP-1/Cr alone. The composite endpoint was defined as end-stage renal disease or 30% reduction of eGFR. These three markers were independently associated with composite endpoint after adjusting for potential confounders [hazard ratio 0.76 (0.59-1.00), P = 0.047 for uEGF/Cr; 1.18 (1.02-1.38), P = 0.028 for uMCP-1/Cr; 0.79 (0.68-0.91), P = 0.001 for uEGF/MCP-1].. In Chinese patients, urinary EGF/MCP-1 was negatively associated with the occurrence of DKD. Moreover, uEGF/MCP-1 had a better ability to predict the composite endpoint and correlated more closely with kidney function decline in advanced DKD as compared with uEGF/Cr or uMCP-1/Cr alone.

Topics: Biomarkers; Chemokine CCL2; Creatinine; Cross-Sectional Studies; Diabetic Nephropathies; Disease Progression; Epidermal Growth Factor; Female; Glomerular Filtration Rate; Humans; Kidney; Kidney Failure, Chronic; Kidney Function Tests; Male; Middle Aged

To identify determinants of early progressive renal decline in type 2 diabetes a range of markers was studied in 1032 patients enrolled into the 2nd Joslin Kidney Study. eGFR slopes estimated from serial measurements of serum creatinine during 5-12 years of follow-up were used to define early renal decline. At enrollment, all patients had normal eGFR, 58% had normoalbuminuria and 42% had albuminuria. Early renal decline developed in 6% and in 18% patients, respectively. As determinants, we examined baseline values of clinical characteristics, circulating markers: TNFR1, KIM-1, and FGF23, and urinary markers: albumin, KIM-1, NGAL, MCP-1, EGF (all normalized to urinary creatinine) and the ratio of EGF to MCP-1. In univariate analysis, all plasma and urinary markers were significantly associated with risk of early renal decline. When analyzed together, systolic blood pressure, TNFR1, KIM-1, the albumin to creatinine ratio, and the EGF/MCP-1 ratio remained significant with the latter having the strongest effect. Integration of these markers into a multi-marker prognostic test resulted in a significant improvement of discriminatory performance of risk prediction of early renal decline, compared with the albumin to creatinine ratio and systolic blood pressure alone. However, the positive predictive value was only 50% in albuminuric patients. Thus, markers in plasma and urine indicate that the early progressive renal decline in Type 2 diabetes has multiple determinants with strong evidence for involvement of tubular damage. However, new, more informative markers are needed to develop a better prognostic test for such decline that can be used in a clinical setting.

Topics: Adult; Albuminuria; Biomarkers; Blood Pressure; Chemokine CCL2; Creatinine; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Disease Progression; Early Diagnosis; Epidermal Growth Factor; Female; Fibroblast Growth Factor-23; Glomerular Filtration Rate; Hepatitis A Virus Cellular Receptor 1; Humans; Kidney; Male; Middle Aged; Predictive Value of Tests; Prognosis; Receptors, Tumor Necrosis Factor, Type I; Risk Assessment; Risk Factors; Time Factors

Increased monocyte chemoattractant protein-1 (MCP-1) and decreased epidermal growth factor (EGF) are promising biomarkers to predict progressive decline in kidney function in non-diabetic kidney diseases. We aimed to evaluate the performance of urinary EGF, MCP-1 or their ratio in predicting rapid decline of GFR in a cohort of Type 2 diabetic patients (T2DM) with diabetic kidney disease (DKD).. T2DM patients (n = 83) with DKD at high risk for renal progression were followed up prospectively. The baseline urine values of MCP-1 to creatinine ratio (UMCP-1), EGF to creatinine ratio (UEGF), EGF to MCP-1 ratio (UEGF/MCP-1) and albumin to creatinine ratio (UACR) were measured. The primary outcome was a decline in estimated glomerular filtration rate (GFR) of ≥25% yearly from baseline.. During follow-up time of 23 months, patients with rapid decline in estimated GFR of ≥25% yearly from baseline had significantly higher baseline levels of UMCP-1, and UACR and lower UEGF and UEGF/MCP-1 ratio. All renal biomarkers predicted primary outcomes with ROC (95%CI) for UMCP-1=0.73 (0.62-0.84), UEGF=0.68 (0.57-0.80), UEGF/MCP-1=0.74 (0.63-0.85), and UACR =0.84 (0.75-0.93). By univariate analysis, blood pressure, GFR, UACR, UMCP-1, UEGF, and UEGF/MCP-1 were associated with rapid decline GFR. By multivariate analysis, UACR, systolic blood pressure, and UMCP-1 or UEGF/MCP-1 were independently associated with rapid GFR decline.. UMCP-1 or UEGF/MCP-1 ratio were associated with rapid renal progression independent from conventional risk factors in DKD.

Topics: Aged; Albuminuria; Biomarkers; Cardiovascular Diseases; Chemokine CCL2; Creatinine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Nephropathies; Disease Progression; Epidermal Growth Factor; Female; Glomerular Filtration Rate; Humans; Male; Middle Aged; Prospective Studies; Risk Factors

The aim of this study was to examine the effect of protein kinase Cbeta inhibition with ruboxistaurin on renal hemodynamic function and urinary biomarkers (monocyte chemoattractant protein-1 [MCP-1] and epidermal growth factor) in renin angiotensin system blockade-treated type 1 diabetic subjects.. Albuminuric subjects were randomized (2:1) to ruboxistaurin (32 mg daily; n = 13) or placebo (n = 7) for 8 weeks. Renal hemodynamic function was measured during clamped euglycemia or hyperglycemia and before and after ruboxistaurin or placebo.. Ruboxistaurin was not associated with between-group differences during clamped euglycemia or hyperglycemia. In a post hoc analysis comparing hyperfilterers with normofilterers during euglycemia, glomerular filtration rate and MCP-1 decreased, whereas the epidermal growth factor-to-MCP-1 ratio increased in hyperfilterers versus normofilterers (all P < 0.05).. The effect of ruboxistaurin is modest and dependent, at least in part, on the level of ambient glycemia and baseline glomerular filtration rate.

Topics: Albuminuria; Blood Pressure; Chemokine CCL2; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Enzyme Inhibitors; Epidermal Growth Factor; Glomerular Filtration Rate; Hemodynamics; Humans; Indoles; Kidney; Maleimides; Protein Kinase C; Protein Kinase C beta

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.

Topics: Adolescent; Adult; Aged; Biomarkers; Biopsy; Capillaries; Diabetic Nephropathies; Epidermal Growth Factor; Female; Humans; Immunohistochemistry; Kidney Tubules; Male; Middle Aged; Oligonucleotide Array Sequence Analysis; Platelet Endothelial Cell Adhesion Molecule-1; Proteinuria; RNA, Messenger; Species Specificity; Vascular Endothelial Growth Factor A

Serum glucocorticoid regulated kinase (SGK-1) is induced in the kidney in diabetes mellitus. However, its role in the proximal tubule is unclear. This study determined the expression and functional role of SGK-1 in PTCs in high glucose conditions. As the epidermal growth factor (EGF) receptor is activated by both EGF and other factors implicated in diabetic nephropathy, the relationship of SGK-1 with EGFR activity was assessed.. mRNA and protein expression of SGK-1 and mRNA expression of the sodium hydrogen exchanger NHE3 were measured in human PTCs exposed to 5 mmol/L (control) and 25 mmol/L (high) glucose. The effects of SGK-1 on cell growth, apoptosis, and progression through the cell cycle and NHE3 mRNA were examined following overexpression of SGK-1 in PTCs. The role of EGFR activation in observed changes was assessed by phospho-EGFR expression, and response to the EGFR blocker PKI166. SGK-1 expression was then assessed in vivo in a model of streptozotocin-induced diabetes mellitus type 2.. A total of 25 mmol/L glucose and EGF (10 ng/mL) increased SGK-1 mRNA (P < 0.005 and P < 0.002, respectively) and protein (both P < 0.02) expression. High glucose and overexpression of SGK-1 increased NHE3 mRNA (P < 0.05) and EGFR phosphorylation (P < 0.01), which were reversed by PKI166. SGK-1 overexpression increased PTC growth (P < 0.0001), progression through the cell cycle (P < 0.001), and increased NHE3 mRNA (P < 0.01), which were all reversed with PKI166. Overexpression of SGK-1 also protected against apoptosis induced in the PTCs (P < 0.0001). Up-regulation of tubular SGK-1 mRNA in diabetes mellitus was confirmed in vivo. Oral treatment with PKI166 attenuated this increase by 51%. No EGF protein was detectable in PTCs, suggestive of phosphorylation of the EGFR by high glucose and downstream induction of SGK-1.. The effects of high glucose on PTC proliferation, reduced apoptosis and increased NHE3 mRNA levels are mediated by EGFR-dependent up-regulation of SGK-1.

Topics: Animals; Cells, Cultured; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Epidermal Growth Factor; ErbB Receptors; Glucose; Humans; Immediate-Early Proteins; Kidney Tubules, Proximal; Phosphorylation; Protein Serine-Threonine Kinases; Rats; RNA, Messenger; Sodium-Hydrogen Exchanger 3; Sodium-Hydrogen Exchangers; Up-Regulation

Tubular atrophy is a major feature of most renal diseases and is closely associated with loss of renal function. The present study sought to investigate tubular epithelial cell apoptosis in experimental diabetic nephropathy and to explore the role of pro-apoptotic [transforming growth factor-beta (TGF-beta) and anti-apoptotic growth factors [epidermal growth factor (EGF)]. The effects of renoprotective therapy with blockade of the renin-angiotensin system (RAS) also were examined.. Six-week-old female Ren-2 rats were injected with streptozotocin (STZ) and maintained diabetic for 12 weeks. Further groups of diabetic rats were treated with the angiotensin-converting enzyme (ACE) inhibitor, perindopril, or the angiotensin II type 1 (AT1) receptor antagonist, valsartan, for 12 weeks.. Widespread apoptosis, identified immunohistochemically by single stranded DNA and TUNEL, was noted in the tubules of diabetic Ren-2 rats. These changes were associated with a 50% decrease in EGF expression and a twofold increase in TGF-beta1 mRNA. Treatment of diabetic Ren-2 rats with either valsartan (20 mg/kg/day) or perindopril (6 mg/kg/day) reduced apoptosis to control levels in association with supranormal levels of EGF mRNA (P < 0.01) and a reduction in TGF-beta1 gene expression (P < 0.05) to that of control rats.. Tubular apoptosis is a prominent feature of diabetic Ren-2 rats that is attenuated by blockade of the RAS in association with modulation of pro- and anti-apoptotic growth factor expression.

Topics: Angiotensin-Converting Enzyme Inhibitors; Animals; Animals, Genetically Modified; Antihypertensive Agents; Apoptosis; Atrophy; Autoradiography; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Epidermal Growth Factor; Female; Fibrosis; Gene Expression; In Situ Hybridization; In Situ Nick-End Labeling; Kidney Tubules; Nephritis, Interstitial; Perindopril; Rats; Renin-Angiotensin System; RNA, Messenger; Tetrazoles; Transforming Growth Factor beta; Valine; Valsartan

The present study reports on the effects of adrenergic blocking agents on the renal growth and on the renal content and urinary excretion of epidermal growth factor (EGF) in streptozotocin-induced diabetic or uninephrectomized rats. Diabetic and uninephrectomized rats were allocated to groups treated with either saline or adrenergic antagonists and compared to controls and sham-operated controls, respectively. 24-hour urine samples were obtained on days 7, 14, and 21 and renal tissue samples on day 21. The 24-hour urinary excretion of EGF from controls and saline-treated diabetic rats was comparable. In adrenergic antagonist treated diabetic rats, it was reduced by at least 40% throughout the study period. Uninephrectomy caused a 50% reduction in the urinary excretion of EGF. This was not influenced by treatment with an adrenergic antagonist. After 3 weeks, saline-treated diabetic rats had an increase of 33% in kidney weight when compared to controls. The adrenergic antagonist treated diabetic groups had a significantly lower increase of 15%. Postnephrectomized renal growth was not affected by adrenergic antagonists. The total renal content of EGF was comparable in the saline-treated diabetic group and the control group, but was reduced by approximately 50% in the kidneys from the adrenergic antagonist treated diabetic groups. Renal EGF mRNA levels were also reduced in adrenergic antagonist treated diabetic rats. In contrast to diabetes, the renal growth following nephrectomy was not affected by adrenergic blocking agents. These results provide evidence for fundamental differences between diabetes-related renal growth and that observed in compensation to nephrectomy and suggest a connection between adrenergic activity, renal growth, and EGF in diabetes.

Topics: Adrenergic alpha-Antagonists; Adrenergic beta-Antagonists; Animals; Blood Glucose; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Epidermal Growth Factor; Female; Gene Expression; In Situ Hybridization; Kidney; Kidney Function Tests; Nephrectomy; Oligonucleotide Probes; Organ Size; Prazosin; Propranolol; Rats; Rats, Wistar; RNA, Messenger

Tamm-Horsfall protein (THP) and epidermal growth factor (EGF) are both synthesized by tubular cells in the distal part of the nephron and excreted with the urine. The present study examines the urinary excretion rates of the two peptides in relation to functional tubular markers in patients with chronic nephropathy. Four groups of patients with moderate to severely reduced renal function were studied: glomerulonephritis (n = 10), diabetic nephropathy (n = 11), tubulointerstitial nephropathy (n = 13), and polycystic kidney disease (n = 8). The renal function was evaluated by glomerular filtration rate (GFR) as an indicator for the general renal function, lithium clearance (C(Li)) as an indicator for proximal tubular function, and absolute distal reabsorption of sodium (ADR(Na)) as an indicator for distal tubular function. The excretion rate of EGF was rather closely correlated with GFR, C(Li) and ADR(Na) (Spearman coefficients of variation 0.88, 0.69, and 0.74, respectively). The correlations between the excretion rate of THP and GFR, C(Li) and ADR(Na) were weaker (Spearman coefficients of variation 0.68, 0.42, and 0.44). When the effect of GFR had been accounted for by multiple variance analyses, the excretion rates of the two peptides were still associated with ADR(Na) but not with C(Li). In conclusion, the urinary excretion rates of especially EGF but also those of THP were correlated with renal function and distal tubular reabsorption of sodium in patients with chronic nephropathy.

Topics: Adjuvants, Immunologic; Adult; Aged; Diabetic Nephropathies; Epidermal Growth Factor; Female; Glomerular Filtration Rate; Glomerulonephritis; Humans; Kidney Failure, Chronic; Kidney Tubules, Distal; Kidney Tubules, Proximal; Loop of Henle; Male; Middle Aged; Mucoproteins; Polycystic Kidney Diseases; Uromodulin

Nitric oxide (NO) contributes to the alterations in glomerular hemodynamics and extracellular matrix accumulation observed in diabetic nephropathy. High glucose concentrations directly inhibit NO production by rat mesangial cells (RMC). However, the role of peptide growth factors and chemokines in regulating NO synthesis by RMC under normal and high glucose conditions has not been studied. Therefore, we examined the effect of IGF-I, EGF, TGF-beta and RANTES on NO production by RMC maintained in normal (5.6 mM) or high glucose (33.3 mM) for 48 h. No synthesis was determined by measuring nitrite accumulation in conditioned media with the Greiss reaction. In normal glucose media, IGF-I, EGF, and RANTES had no effect on nitrite accumulation while TGF-beta inhibited NO synthesis. In high glucose conditions, IGF-I and EGF significantly enhanced NO production. The effects of RANTES and TGF-beta were unchanged by an elevated glucose concentration. EGF-induced stimulation of NO production in high glucose media was associated with parallel alterations in iNOS gene and protein expression. The modest enhancement in nitrite accumulation provoked by IGF-I in high glucose conditions was not accompanied by demonstrable increases in iNOS mRNA abundance or protein content. In conclusion, peptide growth factors modulate the direct inhibitory effect of high glucose on NO production by cultured mesangial cells. These actions in vivo may limit the adverse consequences of reduced NO production in promoting diabetic nephropathy.

Topics: Animals; Blotting, Northern; Blotting, Western; Cell Survival; Cells, Cultured; Chemokine CCL5; Culture Media, Conditioned; Diabetic Nephropathies; Epidermal Growth Factor; Glomerular Mesangium; Glucose; Growth Substances; Insulin-Like Growth Factor I; Nitric Oxide; Nitric Oxide Synthase; Rats; RNA, Messenger; Transforming Growth Factor beta

We have shown that epidermal growth factor (EGF) may be important in diabetic renal hypertrophy. Since EGF is the most potent mitogen for the proximal tubule, it may be relevant to the cellular hyperplasia component in diabetic nephropathy. In order to further clarify the possible alterations of mitogenic effects of EGF on cultured renal cells in hyperglycemic states, the effects of high glucose culture on EGF-induced events and EGF receptors were studied in LLC-PK1 cells with equimolar mannitol being used as an osmotic control. The results showed that high glucose dose-dependently decreased mitogenesis while increasing cellular hypertrophy in LLC-PK1 cells. The dose-response curve of EGF-induced mitogenesis was similar in both normal (11 mM) and high (27.5 mM) glucose cultures. Meanwhile, EGF receptor number and affinity were not changed by high glucose in these cells. Furthermore, mannitol mimicked the growth-suppressive (but not hypertrophic) effects of high glucose cultures. Based upon these findings, we conclude that high glucose did not alter the mitogenic effects of EGF on the LLC-PK1 cells. This was associated with unchanged EGF receptor characteristics. Thus, concurrent with our previous studies, we speculate that it is the increased local EGF level, rather than an increased renal sensitivity to it, which is associated with hyperglycemic tubulopathy.

Topics: Animals; Culture Media; Diabetic Nephropathies; Epidermal Growth Factor; ErbB Receptors; Glucose; LLC-PK1 Cells; Mannitol; Swine

Urinary epidermal growth factor (EGF) excretion is seen as a marker of tubular function, and some studies conclude that EGF excretion can already be reduced early in the development of diabetic renal disease. It is even suggested that EGF could play a role in kidney and glomerular enlargement and hypertrophy in diabetic subjects. We have investigated various groups of subjects, namely healthy controls (n = 5), patients with non-diabetic chronic renal insufficiency (n = 10), and normoalbuminuric (n = 9), microalbuminuric (n = 13) and nephropathic (n = 9) insulin-dependent diabetic subjects. In all subjects glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured using a continuous infusion of 125I-iothalamate and 131I-hippuran, respectively. Diabetic subjects were tested during (near) normoglycaemic conditions. During the renal function test urine was collected for EGF measurement (in ng). With lower GFR values, EGF excretion/min was also lower. GFR correlated well with EGF/min (r = 0.63, p < 0.001). Fractional EGF clearance (EGF/GFR) was comparable in all groups. There was no correlation between urinary albumin excretion rate and EGF excretion in the diabetic subjects (r = -0.18, n.s.) and in all subjects (r = -0.12, n.s.). There was a significant correlation between UAER and GFR (r = -0.51, p < 0.005). No significant correlation could be found between urinary albumin excretion rate (UAER) and EGF/GFR (r = -0.07, n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Albuminuria; Biomarkers; Blood Flow Velocity; Case-Control Studies; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Epidermal Growth Factor; Female; Glomerular Filtration Rate; Humans; Kidney Failure, Chronic; Male; Middle Aged; Renal Circulation

Epidermal growth factor (EGF) concentrations in the plasma, kidneys and urine of 31 streptozotocin-diabetic rats and 21 insulin-treated diabetic rats were measured to study the role of EGF in initiating renal hypertrophy in the diabetic rats. Renal hypertrophy occurred from day 7 in the diabetic rats, but not in the insulin-treated rats. Renal EGF was not different between the diabetic and control rats, while that in the insulin-treated rats was significantly less than in the diabetic rats. There were no significant changes in plasma EGF in any of the rats. Urine EGF was 119 +/- 7.9 ng/day at day 7 in the control rats but it was significantly increased from day 2 in the diabetic rats (320 +/- 52.9 ng/day at day 2 and 298 +/- 18.4 ng/day at day 7), while in the insulin-treated rats it was significantly less than that in the diabetic rats (134 +/- 8.34 ng/day at day 2 and 220 +/- 15.2 ng/day at day 7). Since the kidney is the main source of urine EGF and EGF has been shown to induce renal growth both in vitro and in vivo, we conclude that EGF may have initiated renal hypertrophy in diabetic rats.

Topics: Animals; Diabetes Mellitus, Experimental; Diabetic Nephropathies; Epidermal Growth Factor; Female; Hypertrophy; Insulin; Kidney; Organ Size; Rats; Rats, Inbred Strains

Excretion of epidermal growth factor (EGF) is decreased in renal failure. We assayed it in diabetes mellitus in an attempt to relate it to clinical parameters, esp. those of diabetic nephropathy. EGF excretion declined with age but in all age groups of diabetic patients was below the first percentile for controls. In 26 control and 34 prepubertal diabetic children excretion was correspondingly 1126 +/- 442 and 932 +/- 489 pmol/mmol creatinine (P = 0.087); in 26 control and 42 diabetic adolescents below age 18, 778 +/- 222 and 676 +/- 335 (P = 0.023) and in 81 control and 83 diabetic adults, 371 +/- 153 and 235 +/- 140 (P less than 0.0001). Decreased excretion of EGF was seen in some patients without any diabetic complications. Excretion of EGF was independently and inversely correlated with age and duration of diabetes but not with type of diabetes, treatment, body built, C-peptide, plasma glucose, glycohemoglobin or retinopathy. A positive correlation was seen with creatinine clearance and a negative correlation, with albuminuria, but the strongest and the only independent correlation found by stepwise multiple variable selection was with serum creatinine (r -0.711, P less than 0.0001). EGF excretion was not elevated in patients with hyperfiltration. We conclude that EGF excretion is abnormal in many patients with diabetes and that this abnormality reflects a kidney function different from glomerular filtration or glomerular permeability.

Topics: Adolescent; Adult; Aged; Aging; Child; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Epidermal Growth Factor; Female; Humans; Male; Puberty

To study the relationship between glomerular and tubular function we investigated glomerular filtration rate (GFR), urinary albumin excretion, and urinary excretion of epidermal growth factor (EGF, a mitogenic peptide synthesized in the renal tubular cells) in normal subjects (group I, n = 7) and in Type 1 (insulin-dependent) diabetic patients with normoalbuminuria (group II, n = 11); with incipient nephropathy (microalbuminuria) (group III, n = 9); with nephropathy and normal GFR (group IV, n = 12); and with reduced GFR (group V, n = 8). EGF (nmol 24 h-1) decreased with progressive glomerular involvement, from 7.9 (4.1-10.5) (median and range) in group I, to 6.7 (1.3-9.2) in group II, 5.0 (3.6-7.4) in group III, 4.1 (2.5-9.5) in group IV, and 1.1 (0.1-2.5) in group V. The urinary excretion of EGF was significantly reduced in patients with elevated UAE (group III, IV, and V) compared with normal control subjects (p less than 0.05). A significant correlation between urinary excretion of EGF and GFR (r = 0.71, p less than 0.001) and an inverse correlation between the urinary excretion of EGF and albumin (r = -0.35, p less than 0.05) was demonstrated in the Type 1 diabetic patients with GFR greater than 90 ml min-1. Our study demonstrates that urinary excretion of epidermal growth factor diminishes with increasing nephron impairment, and that renal tubular function as judged by the excretion of EGF is reduced early in the development of diabetic kidney disease.

Topics: Adult; Albuminuria; Biomarkers; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Epidermal Growth Factor; Female; Glomerular Filtration Rate; Humans; Male; Reference Values

Peritoneal effluent in CAPD patients is the result of the interaction between dialysate and patient through the peritoneal membrane. Among the factors transferred from the patient to dialysate are solutes capable of stimulating fibroblasts: Interleukin-I, Interferon-gamma, and other proteins. Insulin is a well known mitogenic coadjuvant able to act sinergistically with other mitogens in the stimulation of fibroblast proliferation under experimental conditions. Our objective has been to study the effect of insulin added to dialysate in vivo on the in vitro mitogen-induced capacity of the nocturnal peritoneal effluent in 8 diabetics. Two different samples were studied: basal and with in vivo added insulin with the patients' usual doses. A Swiss 3T3 line of mice fibroblasts was used for studies, adding 50 microliters of peritoneal effluent. To confirm in vivo potential mitogenic activity, we also added PDBu (Phorbol dibuturate), a well known mitogenic agent, to both samples. Furthermore, another growth factor, EGF (Epidermal growth factor), was also added to 5 other samples. Insulin addition to the CAPD bag transforms a non-mitogenic peritoneal effluent into a mitogenic one (mean: 4.4 times over basal). At the doses used in vivo there is no linear correlation between insulin dose and DNA synthesis (r: -0.28, NS). Both PDBu and EGF in vitro addition induced a remarkable increment in the mitogenic capacity of the peritoneal effluent. We conclude that insulin added to CAPD bags behaves as a remarkable mitogenic coadjuvant for mice fibroblasts. Consequently, its long-term and universal clinical use should be reconsidered.

Topics: Animals; Cells, Cultured; Diabetes Mellitus; Diabetic Nephropathies; Dialysis Solutions; Epidermal Growth Factor; Fibroblasts; Humans; Insulin; Mice; Mice, Inbred Strains; Mitosis; Peritoneal Dialysis, Continuous Ambulatory; Phorbol 12,13-Dibutyrate

Epidermal growth factor (EGF) is a polypeptide mitogen first isolated from mouse submaxillary glands and later from human urine. We have examined the pattern of urinary excretion of human EGF (hEGF) in normal subjects and in diabetic patients with varying degrees of nephropathy. hEGF was measured by homologous radioimmunoassay and expressed in terms of urinary creatinine excretion. On the basis of their albumin excretion rate, the diabetic patients were divided into those with normoalbuminuria (albumin excretion rate 3.5 (1.4-9.8) micrograms/min; mean (range)), microalbuminuria (albumin excretion rate 75 (30-128) micrograms/min) and macroalbuminuria (289 (169-879) micrograms/min). The albumin excretion rate for the normal subjects was 3.7 (1.6-9.7) micrograms/min. The mean (range) hEGF excretion (nmol hEGF/mmol creatinine) was 0.69 (0.47-1.29) for 19 healthy subjects, 0.60 (0.16-1.36) for the normoalbuminuric group (n = 18; NS), 0.47 (0.10-0.83) for the microalbuminuric patients (n = 19; P less than 0.001 vs controls and normoalbuminuric diabetics) and 0.38 (0.10-0.63) for the macroalbuminuric group (n = 18; P less than 0.001 vs controls and normoalbuminuric diabetics). There was an inverse correlation between albumin excretion rate and hEGF: creatinine ratio (r = -0.49; P = 0.02). These results show a progressive decline in hEGF excretion in diabetic patients with varying degrees of nephropathy and do not support the hypothesis that increased kidney size seen in early nephropathy is due to excessive amounts of EGF in the urine.

Topics: Adult; Albuminuria; Diabetic Nephropathies; Epidermal Growth Factor; Female; Humans; Male; Middle Aged