epidermal-growth-factor and Kidney-Tubular-Necrosis--Acute

Topics: Animals; Apoptosis; Epidermal Growth Factor; Fibroblast Growth Factors; Humans; Kidney Tubular Necrosis, Acute; Regeneration; Somatomedins

To examine the relationship between epidermal growth factor (EGF) and prostaglandins (PGs) in recovery of acute tubular necrosis (ATN) induced by gentamicin in rats and the changes of renal tissue PGs with EGF treatment.. Female wistar rats were divided into three groups; normal(NL, n = 7); GM-treated only (Group G, n = 20); GM 200 mg/kg, i.p. x 3 d; GM and EGF-treated (Group G + E, n = 19): EGF(20 micrograms) was given after last GM injection. [3H]thymidine incorporation rate (3HTdR) of renal tissue, serum creatinine concentration (Scr), renal levels of PGE2, 6-keto-PGF1 alpha, TXB2 were measured at day 1,4,8,12 after GM administration.. [3H]thymidine incorporation rate of renal tissue in group G + E was significantly higher than that in group G after toxic injury. The histological lesions of group G + E was less severe than that in group G. 6-keto-PGF1 alpha in group G + E was increased significantly than that in group G, and renal TXB2 in group G + E was lower than that in group G. PGE2 and 6-keto-PGF1 alpha in group G + E was positively correlated with 3HTdR, respectively.. (1) changes of renal prostaglandins may be related to the injury/proliferation of renal tubular epithelial cells in ATN. (2) Administration of exogenous EGF may enhance the release of PGE2 and 6-keto-PGF1 alpha of renal tissue and inhibit the synthesis of renal TXB2. The results indicate that effect of ameliorating recovery of renal tubular epithelial cells of EGF could be partly related to the changes of renal PGs.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Dinoprostone; Epidermal Growth Factor; Female; Gentamicins; Kidney; Kidney Tubular Necrosis, Acute; Rats; Rats, Wistar; Thromboxane B2

We noted previously that ischemic acute tubular necrosis (ATN) induces local expression of MHC products in renal epithelium. The present investigations were conducted to establish the role of IFN-gamma in the regulation of MHC antigen expression in ATN and to explore the changes in cytokine and growth factor expression induced by ischemic renal injury. We produced unilateral ischemic ATN in mice by clamping the left renal pedicle. MHC class I and II steady state mRNA induction was assessed by northern blot analysis, and MHC product was quantified by the extent of binding of radiolabeled monoclonals to tissue homogenates. The steady state mRNA levels for IFN-gamma, IL-2, IL-10, and granulocyte-macrophage CSF were assessed by reverse transcriptase polymerase chain reaction and the levels for transforming growth factor-beta 1 and prepro-epidermal growth factor (ppEGF) were assessed by Northern blot analysis. In the injured kidneys, steady state mRNA levels for IFN-gamma, IL-2, IL-10, granulocyte-macrophage CSF, and transforming growth factor beta-1 were increased, whereas ppEGF mRNA was markedly decreased. The MHC expression was inhibited by treatment of mice with an anti-IFN-gamma mAb (R4-6A2). Murine EGF, administered in an attempt to accelerate recovery, did not reduce the cytokine and MHC changes. These data indicate that ischemic injury, and possibly other forms of injury, triggers a complex circuit of proinflammatory cytokines. This "injury response" could be relevant to clinical renal transplants, where ATN is associated with poor graft outcome.

Topics: Animals; Antibodies, Monoclonal; Base Sequence; Cytokines; Disease Models, Animal; DNA, Complementary; Epidermal Growth Factor; Histocompatibility Antigens; Interferon-gamma; Ischemia; Kidney; Kidney Tubular Necrosis, Acute; Male; Mice; Mice, Inbred BALB C; Molecular Sequence Data; RNA, Messenger; Transforming Growth Factor beta

Acute tubular necrosis induced by aminoglycoside antibiotics and various other nephrotoxins is followed by a regenerative process which leads to the restoration of damaged tubules. Several lines of evidence indicate that tubular regeneration is mediated by polypeptide growth factors such as epidermal growth factor (EGF). Previous studies devoted to cisplatin nephrotoxicity have shown that this agent causes tubular cystic degeneration possibly related to an impairment of renal tissue repair. Thus, we examined on a comparative basis the time course of the regenerative response subsequent to tubular damage induced by tobramycin or cisplatin, particular attention being paid to renal EGF and its receptor. Female Sprague-Dawley rats (160-180 g body weight) were treated during 4 consecutive days with daily doses of 200 mg/kg tobramycin i.p. (BID) or 2 mg/kg cisplatin (once a day). Sham-treated rats were given 0.9% NaCl i.p. following the same protocol. Groups of experimental animals (n = 5-10) were terminated at increasing time intervals (1, 4, 7, 14, 21, 60 days) after cessation of treatment. One hour prior to sacrifice, each individual received i.p. 200 mg/kg 5-bromo-2'-deoxyuridine (BrdU) for the immunohistochemical demonstration of cell proliferation. Blood was collected at the time of sacrifice in order to assess glomerular filtration rate by measuring serum creatinine and BUN levels. Kidneys were analyzed with respect to total EGF determined by RIA in renal tissue homogenates, and soluble EGF was assayed in extracts prepared by centrifugation. Renal tissue was processed for the immunohistochemical detection of S-phase cells, of EGF, of EGF receptors, and of the intermediate filament vimentin, the latter being used as a marker of epithelium dedifferentiation. In absence of nephrotoxic alterations, EGF was immunolocalized in distal tubules, whereas EGF receptor immunostaining was seen in proximal tubules cells. Vimentin immunostaining was confined to glomeruli and blood vessels. Tobramycin and cisplatin caused acute tubular necrosis in proximal convoluted tubules and proximal straight tubules, respectively. Tissue damage was accompanied by renal dysfunction reflected by an elevation of serum creatinine and BUN levels. Tubular necrosis was followed by a proliferative response indicative of tubular regeneration. Regenerative hyperplasia was associated with a reduction of total immunoreactive EGF due to a decrease of tissue-bound proEGF. Tubules undergoing rege

Topics: Analysis of Variance; Animals; Cisplatin; Epidermal Growth Factor; ErbB Receptors; Female; Immunohistochemistry; Kidney; Kidney Tubular Necrosis, Acute; Radioimmunoassay; Rats; Rats, Sprague-Dawley; Tobramycin

Growth factor expression was investigated during the regenerative response after toxic proximal tubular necrosis. Therefore, gentamicin was administered to rats to achieve an experimental model, characterized by the appearance of segment-specific proximal tubular necrosis, that is followed by a regenerative response leading to functional and morphological recovery in a limited time. Four days after the administration of the highest dose, serum creatinine rose to a mean value of 5.8 mg/dl and returned to normal values ten days after the treatment. The S1-S2 segment of the proximal tubules in the cortex became clearly affected by severe toxic necrosis one day after the treatment, while maximal necrosis was observed at days 2 to 4. Only minor injuries were noticed in the other renal compartments. The proliferative response started in the interstitial cells first. The major proliferative wave was localized in the convoluted part of the proximal tubules at days 6 to 8, although proliferation was also prominent among non-proximal tubular cells. A profound interstitial infiltration of leukocytes, including macrophages and T lymphocytes, was observed. Ten days after the treatment the functional and morphological recovery were completed. Slot blot hybridization revealed a decreased EGF and IGF-I mRNA expression from the start of the observation period. While IGF-I mRNA had regained its normal expression at day 10, EGF mRNA was still below control levels. The PDGF-B transcript became more abundant towards the end of our observation. No major changes in the expression of TGF-alpha, TGF-beta 1 and c-fos were detected. Renal EGF-immunoreactivity disappeared from the luminal plasma membrane of the distal tubular cells analogous to the results obtained at the messenger level. However, EGF-staining was lost in the cortex first, hence a topographical association between the loss of EGF-immunoreactivity in the distal tubules and the observed necrotic lesions in the proximal tubules was found. Immunoreactive EGF was never observed in proximal tubular cells from normal, injured or regenerating rat kidneys. We conclude that in this experimental rat model, EGF and IGF-I mRNA expression is decreased during the regenerative response upon severe toxic tubular necrosis. No evidence for a participation of EGF or IGF-I of renal origin in the recovery of the kidney is found.

Topics: Animals; Cell Division; Epidermal Growth Factor; Female; Growth Substances; Insulin-Like Growth Factor I; Kidney; Kidney Tubular Necrosis, Acute; Kidney Tubules, Proximal; Male; Rats; Rats, Sprague-Dawley; Rats, Wistar; Regeneration; RNA, Messenger

Topics: Animals; Epidermal Growth Factor; Female; Gentamicins; Immunohistochemistry; Kidney Tubular Necrosis, Acute; Rats; Rats, Sprague-Dawley

Tubular necrosis induced by various drugs (aminoglycosides, platinum-based anticancer agents) elicits a process of renal tissue repair which involves an increase of cell turnover. The proliferative response remains commensurate with the degree of tubular injury and occurs primarily in the area of tubular epithelium which has suffered injury. After acute renal necrosis, tubular regeneration is associated with a transient dedifferentiation of epithelial cells. This tissue reaction is controlled and leads in most cases to a complete reepithelialization of injured tubules and consequently to a full restoration of normal kidney functions. Recent experimental evidences suggest that EGF (Epidermal growth factor) plays a prominent role in the control of this repair process. By immunocytochemical and biochemical methods we have observed in regenerating kidneys a diminution of the membrane-bound precursor of EGF (prepro-EGF) in distal tubules. Concomitantly, by electron microscopy, EGF immunoreactivity is detected on basolateral membranes of proximal tubules. These experimental data suggest that EGF precursor might be converted into a low molecular weight diffusible factor. The latter is able to interact with the receptors localized on the basolateral membranes of proximal tubules and to induce the tissue repair process.

Topics: Drug-Related Side Effects and Adverse Reactions; Epidermal Growth Factor; Epithelium; Humans; Kidney Tubular Necrosis, Acute; Kidney Tubules; Microscopy, Electron; Protein Precursors; Regeneration

The 35-kDa protein (p35, lipocortin I, annexin I), originally discovered as a Ca(++)-dependent substrate for the EGF receptor tyrosine kinase, binds Ca++ and phospholipids, is developmentally regulated in embryos and has restricted expression in adults. Immunohistochemistry of normal rat kidney shows that p35 is enriched in epithelia of Bowman's capsule, the macula densa, and medullary/papillary collecting ducts, suggesting that p35 is related to specialized renal functions. Light staining is observed in the thick ascending limb; elsewhere, immunoreactivity is nil. Since renal recovery from ischemia involves both hyperplasia and hypertrophy and reportedly is accelerated by EGF, we examined p35 distribution during this process. After 48 hours of recovery, both the distribution and amount of renal p35 are altered. Immunoblots show p35 levels increased at least threefold in whole-kidney homogenates. The expression of p35 is still highly restricted in recovering kidneys; however, the thick ascending limb now stains heavily. This is the first documentation of alterations in annexin levels during a pathophysiologic response. However, our attempts to discern effects of exogenous EGF on the recovery from ischemia were negative for both mitotic index and renal function assays.

Topics: Animals; Annexin A1; Epidermal Growth Factor; Immunohistochemistry; Ischemia; Kidney; Kidney Tubular Necrosis, Acute; Mitosis; Rats; Reference Values; Reperfusion; Tissue Distribution

Aminoglycoside antibiotics act as nephrotoxic drugs, inducing a lysosomal phospholipidosis and necrotic lesions essentially in convoluted proximal tubules. Previous studies have demonstrated that tubular injury caused by these compounds elicits a process of renal tissue repair (tubular regeneration) involving an increase of cell turnover in tubular epithelium. The present study was performed in order to: (i) achieve further insight into the temporal relationship between aminoglycoside-induced phospholipidosis, tubular necrosis, and tubular regeneration; and (ii) approach the control of tubular regeneration after nephrotoxin-induced insult. To investigate the latter point, we examined by immunocytochemistry the intrarenal distribution of epidermal growth factor (EGF) during tubular regeneration. Five groups of female Sprague-Dawley rats (n = 5) were treated for 4 days with gentamicin i.p. at a daily dose of 50 mg/kg delivered in 2 injections per day. Sham-treated animals (n = 5) received an equivalent amount of vehicle (0.9% NaCl) according to the same protocol. Groups of treated rats, and controls, were terminated 16 h (day 1), 4 days, 7 days, 14 days, and 21 days after the end of gentamicin administration. One hour prior to necropsy, each animal was given an i.p. injection of 40 mg 5-bromo-2'-deoxyuridine (BrdU) for the immunocytochemical demonstration of S-phase cells, using an anti-BrdU monoclonal antibody. Renal tissue was processed for light microscopy analysis, namely: a computer-aided morphometry of lysosomes in proximal tubular cells, a single-blind evaluation of gentamicin-induced tubular injury, the measurement of cell proliferation by immunocytochemical detection of BrdU-labeled nuclei, the demonstration of EGF-like immunoreactive material in renal tissue by using anti-rat EGF antiserum and immunogold-silver staining. As revealed by the morphometry of lysosomes in proximal tubular epithelium, the degree of gentamicin-induced phospholipidosis was maximum at day 1 (relative area occupied by lysosomes was increased 25-fold over mean control value) and declined thereafter. In contrast, tubular necrosis reached a peak 4 days after the end of drug administration. In proximal tubular epithelium, the stimulation of cell turnover associated with tubular regeneration showed a peak at day 7 (15-fold the mean control value). Tubular regeneration was also accompanied by mild interstitial hyperplasia. Three weeks after treatment with gentamicin, morphologica

Topics: Animals; Epidermal Growth Factor; Female; Gentamicins; Immunohistochemistry; Kidney Tubular Necrosis, Acute; Kidney Tubules; Lysosomes; Rats; Rats, Sprague-Dawley; Regeneration; S Phase; Time Factors

The effects of administering insulin-like growth factor I (IGF-I) were examined in a model of ischemic acute tubular necrosis in rats. Injury was induced by 75 min of bilateral renal artery occlusion. Compared to rats administered vehicle, rats administered IGF-I (100 micrograms/day via continuous subcutaneous infusion) had significantly lower serum creatinine and blood urea nitrogen levels over the course of 7 days postocclusion. Glomerular filtration rate as determined by inulin clearance was examined on day 2 postocclusion and was significantly increased in IGF-I-treated animals (0.16 +/- 0.02 ml per min per 100 g of body weight) compared to vehicle-treated controls (0.08 +/- 0.02 ml per min per 100 g of body weight). The weight loss that occurred during the course of acute tubular necrosis was ameliorated by IGF-I. Mortality was reduced from 36.7% in vehicle-treated rats to 7.1% in rats administered IGF-I. Histologically, there was much less renal injury evident at day 7 postocclusion in the IGF-I-treated rats compared to vehicle-treated controls. In contrast, growth hormone (200 micrograms administered subcutaneously for 4 days) did not affect recovery of renal function or reduce mortality postreperfusion. This report demonstrates a beneficial effect of IGF-I administration in the setting of acute tubular necrosis. Several properties of IGF-I render it a pharmacological agent with excellent potential for treatment of this condition in humans.

Topics: Animals; Body Weight; Epidermal Growth Factor; Growth Hormone; Insulin-Like Growth Factor I; Kidney; Kidney Tubular Necrosis, Acute; Male; Rats; Rats, Sprague-Dawley

The distribution of epidermal growth factor (EGF) was examined by immunocytochemistry in the kidneys of rats exposed to amikacin, an aminoglycoside antibiotic causing tubular necrosis at high dose. Five-animal groups were treated for 4 or 10 days with amikacin at daily doses of 15, 40, 80 or 200 mg/kg. The drug was delivered i.p. twice a day. One hour before termination, each rat received an i.p. injection of [3H] thymidine to evaluate DNA synthesis in renal tissue. After sacrifice, the kidneys were processed for morphological (semithin and paraffin sections) and biochemical analysis (measurement of DNA synthesis by [3H] thymidine incorporation in vivo). Amikacin induced in proximal tubules a dose-related lysosomal phospholipidosis, which was assessed by the morphometric evaluation of altered lysosomes ("myeloid bodies") on semithin section. However, frank evidence of acute tubular necrosis was only observed in rats receiving amikacin at a daily dose of 200 mg/kg. Concomitantly with the development of tubular necrosis, there was a rise in the rate of cell turnover, reflected by an increase of DNA synthesis in renal tissue. This sign of tubular regeneration was accompanied by a redistribution of EGF immunoreactivity, as revealed by immunocytochemical staining. Within renal cortex of control rats, EGF immunoreactivity predominantly appeared in distal tubules and collecting ducts (97% of examined tubular sections). In contrast, in treated animals where the renal cortex displayed evidence of tubular necrosis/regeneration, EGF immunoreactivity was frequently associated with proximal tubules (more than 30% of examined tubular sections, as compared to 3% in controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Amikacin; Animals; Cell Division; DNA; Epidermal Growth Factor; Female; Immunohistochemistry; Kidney; Kidney Tubular Necrosis, Acute; Lysosomes; Phospholipids; Rats; Rats, Inbred Strains; Regeneration; Tissue Distribution

Tubular necrosis elicits a process of renal tissue repair characterized by an increase of cell turnover in tubular epithelium. The present study was undertaken to examine the distribution of epidermal growth factor (EGF) and/or of its larger precursor proEGF in the kidney undergoing tubular regeneration. Sprague-Dawley rats were exposed to various drugs (aminoglycosides or platinum-based anticancer agents) known to induce tubular necrosis. The proliferative response resulting from renal tissue damage was measured by the incorporation of [3H]thymidine into DNA of renal cells. EGF immunoreactivity was evidenced by immunocytochemical staining, using anti-EGF antibody and immunogold-silver staining. Concomitantly with the increase of cell proliferation resulting from tubular injury, a redistribution of EGF immunoreactivity was observed in renal tissue (from the inner stripe of outer medulla towards renal cortex). Amazingly, EGF was detected in proximal tubules of nephrotoxin-treated rats whereas, in the kidneys of control animals, it was almost exclusively found in distal tubules and collecting ducts. Insofar as the administration of exogenous EGF has recently been shown to enhance renal tubular regeneration after ischaemic injury [Humes et al: J Clin Invest 1989; 84:1757-1761], our observations lend further support to the concept that EGF might be involved in renal tissue repair.

Topics: Aminoglycosides; Animals; Anti-Bacterial Agents; Carboplatin; Cell Division; Cisplatin; DNA; Epidermal Growth Factor; Female; Immunohistochemistry; Kidney; Kidney Tubular Necrosis, Acute; Rats; Rats, Inbred Strains; Regeneration

1. Severe, ischaemic, acute tubular necrosis was induced in rats by bilateral occlusion of the renal arteries. The experimental group received exogenous epidermal growth factor infused directly into the renal arterial circulation. Serum creatinine concentration was measured daily for 1 week. Epidermal growth factor receptor binding was measured by autoradiography of whole kidney sections. Renal cell proliferation was measured by incorporation of [3H]thymidine into DNA. 2. Serum creatinine concentration increased after acute tubular necrosis with a peak at 48 h and remained elevated above control levels after 7 days. Binding of radiolabelled epidermal growth factor occurred in all regions of the kidney 48 h after ischaemia. Treatment with exogenous epidermal growth factor attenuated the rise in serum creatinine by 4 days after acute tubular necrosis and after 7 days serum creatinine was lower than in animals that did not receive epidermal growth factor. Infusion of epidermal growth factor also increased renal DNA synthesis. 3. The increase in epidermal growth factor binding in the kidney after acute tubular necrosis and the attenuation of the increase in serum creatinine concentration by administration of exogenous epidermal growth factor, suggest a role for epidermal growth factor in recovery from ischaemic damage. The increase in DNA synthesis in response to epidermal growth factor indicates that its effect may be due, at least in part, to accelerated tubular cell proliferation.

Topics: Acute Kidney Injury; Animals; Creatinine; DNA; Epidermal Growth Factor; ErbB Receptors; Kidney; Kidney Tubular Necrosis, Acute; Male; Mice; Mitosis; Rabbits; Rats; Rats, Inbred Strains; Thymidine; Time Factors