A novel nuclear factor κB inhibitor, dehydroxymethylepoxyquinomicin, ameliorates puromycin aminonucleoside-induced nephrosis in mice

BACKGROUND/AIMS

Minimal-change nephrotic syndrome (MCNS) is a kidney disease defined by selective proteinuria and hypoalbuminemia occurring in the absence of cellular glomerular infiltrates or immunoglobulin deposits. Recent observations suggest that nuclear factor κB (NF-κB) of podocyte is strongly associated with the development of proteinuria in MCNS. Dehydroxymethylepoxyquinomicin (DHMEQ) is a novel NF-κB inhibitor that potently inhibits DNA-binding activity of NF-κB, resulting in several therapeutic effects in various pathological conditions. We conducted this study to ask whether DHMEQ may ameliorate the nephrosis in mice induced by puromycin aminonucleoside (PAN), which is considered to be an animal model for MCNS.

METHODS/RESULTS

Pretreatment with DHMEQ alleviated the proteinuria and reversed the serum abnormalities in mice nephrosis induced by 450 mg/kg of PAN. Increased serum interleukin-6 level in PAN-induced nephrosis was also completely suppressed by DHMEQ. Electron microscopic analyses of glo-meruli indicated that DHMEQ can inhibit the podocyte foot process effacement via blocking the translocation of podocyte NF-κB from cytoplasm to nucleus.

CONCLUSIONS

These results suggest that DHMEQ can be a potential therapeutic agent for MCNS.

[Relationship between glomerular nephrin expression and oxidative stress reaction in rats with adriamycin-induced nephrosis]

OBJECTIVE

It has been proposed that nephrotic syndrome is a consequence of an imbalance between oxidant and anti-oxidant activity. Nephrin plays an important role in maintaining glomerular filtration barrier. This study aimed to explore the relationship between the expression of glomerular nephrin and oxidative stress reaction in rats with adriamycin (ADR)-induced nephrosis, and the protection of prednisone and vitamin E against renal injuries.

METHODS

Nephrosis was induced by single intravenous injection of ADR (5 mg/kg). The prednisone intervention group was administered with prednisone (10 mg/kg daily) between 1 and 4 weeks after ADR injection. The vitamin E intervention group received vitamin E of 20 mg/kg daily from 1 week before ADR injection till to 4 weeks after ADR injection. Control rats were intravenously injected with normal saline. After 7, 14, 21 and 28 days of ADR injection, the indexes of oxidative stress reaction of the renal cortex, malondialdehyde (MDA), superoxide dismutase (SOD) and total antioxidative capacity (T-AOC), were measured using the chemical chromatometry. The protein expression of glomerular nephrin was measured by immunohistochemistry.

RESULTS

Prednisone or vitamin E treatment reduced urinary protein from 14 days to 28 days after ADR injection. MDA levels of renal cortex increased, while renal activities of SOD and T-AOC as well as nephrin protein contents decreased in untreated nephrosis group from 7 days after ADR injection compared with those in the control rats. Compared with the untreated nephrosis group, prednisone treatment resulted in an increase in nephrin protein contents 28 days after ADR injection; Vitamin E treatment decreased renal MDA levels and increased renal activities of SOD and T-AOC and nephrin protein contents 28 days after ADR injection. Nephrin staining showed a sable linear-like pattern along the capillary loops of glomerulus in the control rats. Nephrin staining presented a light tan discontinuous short linear-like or punctiform pattern along the capillary loops of glomerulus in the untreated ADR group. Prednisone or vitamin E treatment ameliorated abnormal expression of nephrin induced by nephrosis. Glomerular nephrin expression level was negatively correlated with renal MDA level and positively correlated with renal activities of SOD and T-AOC.

CONCLUSIONS

A reduction of glomerular nephrin expression is closely related to oxidative stress reaction. Prednisone and vitamin E have protective effects against renal injuries induced by ADR in rats.

Determinants of amount of contrast utilized in patients undergoing percutaneous coronary procedures

OBJECTIVE

To determine predictors of contrast amount during coronary angiography and percutaneous coronary intervention.

BACKGROUND

Contrast-induced nephropathy is a leading cause of hospital-acquired acute renal insufficiency. During percutaneous coronary procedures, contrast amount is a major risk factor incriminated in development of contrast-induced nephropathy.

METHODS

Demographic and procedural details were obtained for consecutive patients undergoing percutaneous coronary procedures between January 2002 and October 2005 (N=962, mean+/-standard error of contrast amount: 216.6+/-3.0 ml) at a tertiary care hospital.

RESULTS

A significant difference (P value <0.05) in unadjusted mean contrast volume was observed between subgroups of percutaneous coronary intervention vs. coronary angiography, patients with a history of coronary artery bypass grafting, patients undergoing additional procedures and multivessel and multisite percutaneous coronary interventions. On General Linear Model analysis, independent predictors (beta coefficient, 95% confidence interval, P value) of increased contrast amount during percutaneous coronary procedures were history of coronary artery bypass grafting (44.4, 30.6-58.2, <0.001), type of coronary procedure (85.2, 73.4-97.0, <0.001 for percutaneous coronary intervention vs. coronary angiography), number of interventions and number of additional procedures performed. Among additional procedures, rotablation, intravascular ultrasound and Angiojet were associated with increased contrast use. No significant independent effect on the contrast amount was observed with percutaneous coronary intervention location (right coronary artery vs. left anterior descending artery vs. circumflex artery) site (ostial vs. proximal vs. mid vs. distal) of percutaneous coronary intervention or with interventions on chronic total occlusions on the contrast amount.

CONCLUSION

Data from our study could guide the coronary angiographer in moderating the volume of contrast utilized as well as assist with the elective planning of complex therapeutic procedures.

Protective effect of radical scavenger edaravone against puromycin nephrosis

AIM

Recent studies have indicated that reactive oxygen species (ROS) play a role in the pathogenesis of glomerular injury leading to proteinuria in nephrotic syndrome. In the present investigation, we examined the effects of the radical scavenger edaravone administered at various time points to rats with puromycin nephrosis.

MATERIALS AND METHODS

35 Wistar rats were divided into five groups: treatment with puromycin aminonucleoside (PAN) alone, treatment with PAN followed by edaravone in the early period, treatment with PAN followed by edaravone administration in the late period, treatment with PAN and administration of edaravone for the whole experimental period, and untreated controls. On Days 3, 6 and 9, urinary protein excretion was measured. The levels of glomerular thiobarbituric acid-reactive substance (TBArs) were determined in all animals on Day 10.

RESULTS

On Day 9, rats that had been administered edaravone showed reduced urinary protein excretion and reduced glomerular TBArs. In particular, edaravone administration in the late period, during which proteinuria was most acute, had the effect of reducing the severity of proteinuria. Glomerular TBArs were suppressed to the control level. Our results indicate that edaravone exerts a protective effect in the acute phase of PAN nephrosis when administered as antioxidant therapy at the onset of proteinuria.

CONCLUSIONS

Edaravone can ameliorate urinary protein excretion after the onset of proteinuria in nephrotic syndrome.

Effect of cyclosporine and sirolimus on the expression of connective tissue growth factor in rat experimental chronic nephrotoxicity

BACKGROUND/AIMS

Connective tissue growth factor (CTGF) is a pro-fibrotic growth factor that acts downstream of transforming growth factor (TGF)-beta. However, CTGF regulation remains unknown. We tried to determine the effect of two commonly used immunosuppressants, cyclosporine (CsA) and sirolimus (SRL), on CTGF expression in a model of chronic nephrotoxicity.

METHODS

Adult Sprague-Dawley rats kept on a low-salt diet were treated daily for 4 weeks with vehicle (VH), SRL (0.3 mg/kg), CsA5 (5 mg/kg), CsA10 (10 mg/kg) or both CsA5 and SRL. CTGF and TGF-beta1 expressions were evaluated by Northern blot. Functional and histologic parameters in addition to number of apoptotic cells were determined.

RESULTS

At 28 days, both CsA doses were capable of inhibiting CTGF mRNA expression to levels similar to control. On the other hand, SRL increased CTGF expression by 3.5-fold. However, addition of CsA to SRL completely reversed that trend and returned levels to control. The results were different for TGF-beta1, which was increased by both CsA and SRL and to a greater extent by the drug combination.

CONCLUSION

Unlike TGF-beta, CTGF does not seem to play an important role in CsA-induced chronic nephrotoxicity. In addition, calcineurin-dependent pathways are likely involved in CTGF regulation.

Relaxin improves renal function and histology in aging Munich Wistar rats

Administration of recombinant human relaxin (rhRLX) to conscious, chronically instrumented rats increases GFR and effective renal plasma flow (ERPF) and decreases effective renal vascular resistance (ERVR) with no significant change in mean arterial pressure. The Munich Wistar albino rat shows progressive chronic nephrosis with age and therefore was used to determine the functional and histologic consequences of rhRLX on matrix remodeling in the kidney of older rats. RLX-infused rats showed increased GFR and ERPF with decreased ERVR. Furthermore, in a double-blinded examination, the renal histology showed a significant decrease in glomerular and tubular collagen deposition in the rhRLX-infused aged rats. During short-term rhRLX administration (24 h), gelatinase activity was found to be essential for renal vasodilation and hyperfiltration. Surprisingly, after 20 d, improved renal function was insensitive to the inhibition of gelatinase activity, suggesting that collagen degradation in these rats had permanently altered the matrix of the renal vasculature. In conclusion, long-term administration of rhRLX improves renal function and ameliorates renal pathology in an aging rat model. The biphasic action of rhRLX on the kidney indicates that, acutely, the vessels dilate, causing increased filtration and renal blood flow with decreased vascular resistance as a result of upregulation of gelatinase activity. Subsequently, the renal vessels undergo alteration in supporting matrix, showing increased blood supply even in the face of acute matrix metalloproteinase inhibition, most likely as a result of the inhibitory properties of RLX on collagen production or increased collagen breakdown.

Effect of zelandopam, a dopamine D1-like receptor agonist, in puromycin aminonucleoside nephrosis rats

The present experiment was designed to investigate the role of peripheral dopamine D1-like receptors and to evaluate the prophylactic effect of zelandopam, a dopamine D1-like receptor agonist, on puromycin aminonucleoside (PA)-induced nephrosis in rats. Rats were divided into six groups (n=10 per group): 0.9% saline-injected rats (control); PA-injected rats (PAN); PA-injected rats treated with the selective dopamine D1-like receptor agonist zelandopam (30, 100, 300 mg/kg p.o. twice a day); PA-injected rats treated with prednisolone (1 mg/kg p.o. once a day). Nephrosis was induced in rats with a single intravenous injection of PA at a dose of 50 mg/kg. The effects of zelandopam and prednisolone in PA nephrosis rats were evaluated before injection of PA and at 7 and 14 days after injection. PA-induced nephrosis was characterized by an increase in urinary protein excretion (proteinuria) and plasma total cholesterol. Zelandopam dose-dependently attenuated the increase in proteinuria and total cholesterol. Prednisolone significantly attenuated the increase in proteinuria and total cholesterol and resulted in a significant decrease in body weight. The present study demonstrates for the first time that zelandopam, a selective dopamine D1-like receptor agonist, is effective in blunting the development of PA-induced nephrosis, and that the effects of zelandopam are dose dependent.

Gentamicin-induced nephrotoxicity and protective effect of caffeic acid phenethyl ester in rats

The objective of this study was to investigate the beneficial effects of caffeic acid phenethyl ester (CAPE) on gentamicin (GM)-induced nephrotoxicity in Wistar rats. Twenty-one adult Wistar rats were divided into three groups as follows: control group, GM and GM + CAPE group. Control group rats were injected with 5% ethanol, GM group rats were treated with 100 mg/kg GM and GM + CAPE group were pretreated with 10 mumol/kg CAPE for 2 days, then exposed to GM at the same dose. Drug injections were applied for 12 days. Twenty-four hours after the last injection, rats were killed and kidneys were quickly removed. Tissue malondialdehyde (MDA) measurements and microscopic examination of kidneys were performed. In the GM group, significant increases in MDA levels were observed (P < 0.05). These changes were found to be normalized in the GM + CAPE group. Exposure to GM caused necrosis of tubular epithelial cells. Necrosis of tubules were found to be prevented by CAPE pretreatment. In conclusion, CAPE exerted an improvement on GM-induced nephrotoxicity, possibly, at least in part through inhibition of the production of oxygen free radicals that cause lipid peroxidation.

Inhibition of Matrix Metalloproteinases During Chronic Allograft Nephropathy in Rats

BACKGROUND

Chronic allograft nephropathy (CAN) belongs to the major causes of long-term kidney allograft failure. One of the histologic hallmarks of CAN is interstitial fibrosis, influenced by matrix metalloproteinases (MMPs) that are controlling extracellular matrix (ECM) degradation. Whether MMPs affect the development and progression of CAN is not clear so far. To analyze the role of MMPs in CAN, we investigated the effects of an early and a late application of BAY 12-9566, an inhibitor of MMP-2, -3, and -9 on the development and progression of CAN in a rat kidney-transplantation model.

METHODS

Fisher kidneys were orthotopically transplanted into Lewis recipients that were treated with BAY 12-9566 (15 mg/kg per day) or vehicle either for the first 10 days after transplantation (early treatment) or from week 12 to week 20 after transplantation (late treatment). Proteinuria was analyzed every 4 weeks up to week 20 after transplantation when kidney grafts were removed for further analysis.

RESULTS

Early MMP-inhibition resulted in a significantly reduced 24-hour protein excretion that was paralleled by a lower grade of CAN after 20 weeks. However, late MMP inhibition starting at week 12 after transplantation resulted in significantly higher proteinuria and a higher grade of CAN as compared with controls. Furthermore, transforming growth factor-beta and platelet-derived growth factor-B chain mRNA levels were significantly increased in these animals.

CONCLUSIONS

Inhibition of MMPs early after transplantation reduced the development and progression of CAN but promoted CAN if initiated at later stages. Thus, MMPs are involved in the development and progression of CAN.

Retinoids as a potential treatment for experimental puromycin-induced nephrosis

1 Puromycin aminonucleoside (PAN)-induced nephrosis is a model of human minimal change disease. In rats, PAN induces nephrotic-range proteinuria, renal epithelial cell (podocyte) damage, infiltration of mononuclear leukocytes, and apoptosis of several renal cell types. 2 Retinoic acid (RA) modulates a wide range of biological processes, such as inflammation and apoptosis. Since renal damage by PAN is characterized by inflammatory infiltration and epithelial cell death, the effect of treatment with all-trans RA (tRA) was examined in the PAN nephrosis model and in the cultured differentiated podocyte. 3 Treatment with tRA 4 days after PAN injection did not inhibit the proteinuria peak but reversed it significantly. However, treatment with tRA both before and 2 days after the injection of PAN protected the glomerular epithelial cells, diminishing the cellular edema and diffuseness of the foot process effacement. Preservation of the podocyte architecture correlated with the inhibition of proteinuria. The anti-inflammatory effect of tRA was evidenced by the inhibition of PAN-induced interstitial mononuclear cell infiltration and the decreased renal expression of two molecules involved in monocyte infiltration: fibronectin and monocyte chemoattractant protein-1. TUNEL assays showed that tRA inhibited the PAN-induced apoptosis of cultured differentiated mouse podocytes. 4 We conclude that tRA treatment may prevent proteinuria by protecting the podocytes from injury and diminishing the interstitial mononuclear infiltrate in the model of PAN nephrosis. Retinoids are a potential new treatment for kidney diseases characterized by proteinuria and mononuclear cell infiltration.

Effect of DTPA on the nephrotoxicity induced by uranium in the rat

The only treatment proposed after human contamination with MOX (mixed oxide of uranium and plutonium) is diethylenetriaminepentaacetic acid (DTPA), because plutonium is considered to be the major risk. However, both DTPA and uranium are nephrotoxic at high dosages and DTPA has been shown to increase in vitro the cytotoxicity induced by uranium on cultured epithelial tubular cells. This work aimed to test this effect in vivo. Rats were injected with subtoxic (57 microg kg(-1)) to toxic (639 microg kg(-1)) amounts of uranium as nitrate at 0 h, they received two DTPA injections (30 micromol kg(-1)) at 2 min and 24 h and were euthanased at 48 h. The nephrotoxic effects were evaluated by measurement of the body weight gain, food and water intake, measurement of biochemical parameters in urine and blood, and histological examination of one kidney. The main result was that DTPA did not increase the nephrotoxicity induced by uranium in the range of concentrations tested, which was inconsistent with the in vitro results.

[Experimental study of compound salvia injection in preventing and treating chronic nephrotoxicity induced by cyclosporin A in rats]

OBJECTIVE

To explore the mechanism of protective effect of Compound Salvia Injection (CSI) on experimental cyclosporin A induced nephrotoxicity.

METHODS

Rats were on low-salt diet and cyclosporin A (CsA) was administered once a day through gastrogavage at dosage of 30 mg/kg.d for 28 days. Expression of the mRNA for intrarenal transforming growth factor-beta 1 (TGF-beta 1) and renin was measured by reverse transcription-polymerase chain reaction (RT-PCR). Intrarenal expression of TGF-beta 1 and Collagen IV was determined by immunohistochemical assays. The effects of CSI on these changes were also evaluated.

RESULTS

Chronic CsA-induced nephropathy might be correlated to TGF-beta 1 and renin mRNA up-regulation as well as matric proteins accumulation in interstitium. CSI could reduce these changes.

CONCLUSION

Decreased CsA-related TGF-beta 1 and renin upregulation expression and accumulation of matrix proteins in the kidney might be related to the protective mechanism of CSI on CsA-induced chronic nephrotoxicity.

Involvement of angiotensin II in development of spontaneous nephrosis in Dahl salt-sensitive rats

We investigated the effect of angiotensin-converting enzyme inhibition on spontaneous nephrosis in Dahl salt-sensitive (Dahl/S) rats. Dahl/S rats fed on a normal sodium diet spontaneously developed nephrosis and mild hypertension from a young age. In young Dahl/S rats, an angiotensin-converting enzyme inhibitor, imidapril, attenuated the development of proteinuria accompanied by a decrease in blood pressure. Methylprednisolone, a potent therapeutic agent for proteinuria, did not affect the development of nephrosis. An angiotensin AT1 receptor antagonist, losartan, but not a Ca2+ channel blocker, verapamil, inhibited the development of nephrosis while both agents decreased blood pressure to a similar extent as imidapril. In mature Dahl/S rats, imidapril suppressed not only the development of proteinuria but also the glomerular lesions. It is concluded that the development of spontaneous nephrosis in Dahl/S rats is mediated by angiotensin II.

Effect of intravenous calcium administration on gentamicin-induced nephrotoxicosis in ponies

OBJECTIVE

To determine whether supplemental i.v. calcium administration would attenuate or prevent gentamicin-induced acute renal failure, defined as an increase in serum creatinine concentration > or = 50% above baseline.

ANIMALS

10 healthy pony mares.

PROCEDURE

Pony mares were randomly assigned to receive calcium at a dosage of 20 mg/kg of body weight or saline solution i.v., twice daily for 14 days. All pony mares received gentamicin at a dosage of 20 mg/kg i.v. every 8 hours for 14 days. Gentamicin pharmacokinetic, serum biochemical, and urinalysis data were measured every other day for the 14-day study period. Renal histologic examination was performed, and results were scored at the end of the 14-day period.

RESULTS

4 of 5 mares not receiving calcium supplementation developed acute renal failure. Only 1 of the 5 mares receiving calcium supplementation developed acute renal failure. Over the course of the study, pony mares receiving calcium supplementation had significantly fewer changes in urinalysis variables, and significantly less microscopic renal damage.

CONCLUSION

Daily i.v. administration of calcium attenuated gentamicin-induced acute renal failure.

CLINICAL RELEVANCE

Calcium supplementation may help diminish the risk of acute renal failure associated with aminoglycoside antibiotics.

Protection from cisplatin nephrotoxicity by A68828, an atrial natriuretic peptide

The ability of a 13 amino-acid analog of atrial natriuretic peptide (ANP), A68828, to prevent development of cisplatin toxicity was evaluated in a rat model. ANP (1 microgram/kg/min), A68828 (10 micrograms/kg/min), A68828 (50 micrograms/kg/min), or peptide buffer was given as an intravenous infusion over 1 h beginning 15 min prior to an infusion of 5 mg/kg cisplatin. Animals receiving cisplatin plus peptide buffer vehicle developed predictable renal failure, with mean plasma creatinine and blood urea nitrogen concentrations of 1.09 +/- 0.09 mg/dL and 50.13 +/- 5.96 mg/dL, 72 h after treatment. ANP and A68828 (10 micrograms/kg/min) attenuated the increase in these indices of nephrotoxicity (mean plasma creatinine 0.86 +/- .06 mg/dL and 0.76 +/- 0.11 mg/dL, respectively). Surprisingly, the higher dose of A68828 (50 micrograms/kg/min) did not reduce cisplatin nephrotoxicity (72-h plasma creatinine 1.61 +/- 0.34 mg/dL). These results indicate that a short-term infusion of ANP or the analog A68828 can reduce the severity of cisplatin toxicity. At high doses of A68828 the beneficial effects of treatment may be lost.

Dup 753 prevents the development of puromycin aminonucleoside-induced nephrosis

The appearance of nephrotic syndromes such as proteinuria, hypoalbuminemia, hypercholesterolemia and increase in blood nitrogen urea, induced in rats by injection of puromycin aminonucleoside was markedly inhibited by oral administration of Dup 753 (losartan), a novel angiotensin II receptor antagonist, at a dose of 1 or 2 mg/kg per day. The results suggest a possible involvement of the renin-angiotensin system in the development of puromycin aminonucleoside-induced nephrosis.

Pharmacological activities of a novel thienodiazepine derivative as a platelet-activating factor antagonist. Effects on microvascular permeability, hypotension and nephrosis

The effects of a newly synthesized platelet-activating factor (PAF) antagonist, (S)-(+)-6-(2-chlorophenyl)-3-cyclopropanecarbonyl-8,11- dimethyl-2,3,4,5-tetrahydro-8H-pyrido[4',3':4,5]thieno[3,2-f] [1,2,4]triazolo[4,3-a][1,4]diazepine (E-6123, CAS 131614-02-3) on microvascular permeability, systemic hypotension and nephrosis were investigated. E-6123 inhibited PAF injection-induced microvascular permeability (edema) in guinea pigs after oral administration at 3 micrograms/kg. The inhibitory effects of E-6123 were very potent compared to those of other PAF antagonists. E-6123 reversed PAF and/or endotoxin injection-induced hypotension in rats after intravenous administration at 3 micrograms/kg. The increase in urinary protein excretion of rats in which nephrosis had been induced by intraperitoneal injection of aminonucleoside was not inhibited by oral administration of E-6123 at 10 mg/kg/d.

Amelioration of glomerular injury in doxorubicin hydrochloride nephrosis by dimethylthiourea

The hydroxyl radical scavengers dimethylthiourea (DMTU), sodium benzoate, and dimethylsulfoxide (DMSO) were administered to rats before doxorubicin hydrochloride (ADR) (5 mg/kg, IV) to probe the role of free radicals in mediating proteinuria in doxorubicin hydrochloride nephrosis (AN). Because ADR stimulates free radical production, the role of renal glutathione was also evaluated; glutathione metabolism is involved in tissue detoxification processes. DMTU administration to rats with AN caused a significant (p less than 0.01) reduction in their proteinuria after 7 days (52.84 +/- 13.21 mg/24 hours) when they were compared with ADR controls (155.81 +/- 20.16 mg/24 hours). In similar fashion, their urine albumin excretion was also significantly reduced when compared with that of ADR controls (11.13 +/- 2.75 mg/24 hours vs 32.08 +/- 4.14 mg/24 hours; p less than 0.01). DMTU-treated rats also had significantly (p less than 0.001) reduced urinary protein and albumin excretion at 14 days when compared with rats that received ADR alone. The urinary excretion of lysozyme and N-acetyl-glucosaminidase, markers of renal tubular injury, were significantly increased after 7 or 14 days in rats with AN, despite DMTU treatment. Creatinine clearance was significantly reduced (p less than 0.05) in rats receiving ADR alone (0.223 +/- 0.011 ml/min/100 gm) when compared with that in normal controls (0.331 +/- 0.027 ml/min/100 gm) or DMTU-treated rats (0.289 +/- 0.035 ml/min/100 gm). Unlike DMTU, neither sodium benzoate nor DMSO reduced proteinuria in rats with AN.(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital nephrosis as a cause of elevated alpha-fetoprotein

Two cases of congenital nephrosis were detected through routine maternal serum alpha-fetoprotein (MSAFP) screening of 95,135 patients. No other cases of congenital nephrosis from this group were reported, resulting in an incidence of approximately one in 47,500 in this low-risk population. In both of these cases, similar to other reported cases of congenital nephrosis having MSAFP screening, the protein concentrations were greater than or equal to 10 multiples of the median (MOM). Therefore, in the case of an MSAFP over 10 MOM and a normal ultrasound examination, congenital nephrosis should be included in counseling regarding the possibility of undetected malformations. Furthermore, in the case of a pregnancy with elevated amniotic fluid AFP with negative acetylcholinesterase and normal ultrasound, the possibility of congenital nephrosis should be mentioned, regardless of family history or ancestry. When a pregnancy is terminated because of these biochemical findings, special and immediate attention to the fetal kidneys using electron microscopy is necessary to evaluate properly the possibility of congenital nephrosis.

[Effects of human Cu, Zn-superoxide dismutase in aminonucleoside nephrosis--evaluation of the morphology and glomerular basement membrane anionic charge sites]

It was examined whether superoxide dismutase (SOD) had protective effects in puromycin aminonucleoside nephrosis (PAN). Nephrotic rats were induced by a single intraperitoneal injection of puromycin aminonucleoside (PA, 60 mg/kg). Subcutaneous administration of SOD (30 mg/kg) was started the day before PA injection and continued every 24 hours. Animals were sacrificed 10 days later to assess the morphology and glomerular basement membrane anionic charge sites (CSs). GBM CSs were stained in vitro with polyethyleneimine (PEI) and studied by electron microscopic examination. The SOD-injected group had a significant reduction of urinary protein excretion compared to the PA-treated group. Light microscopy revealed that vast majority of glomeruli in PA-treated group had segmental mesangial expansion and epithelial cell adhesions of the glomerular tuft to Bowman's capsule. Contrasted to these changes in the PA group, glomeruli from SOD-treated group showed less severe morphologic changes. On electron microscopy, the PA-treated rats exhibited marked glomerular epithelial loss of foot processes, epithelial attenuation, cytoplasmic vacuolization and protein reabsorption droplets. The SOD-treated animals demonstrated a lesser degree of epithelial loss of foot processes with a few protein reabsorption droplets. There was also a significant decrease in GBM lamina rara externa CSc stained with PEI in PAN compared to the control. The SOD-treated rats had a significant increase in GBM CSs compared to those of the PAN rats. SOD has protective effects in urinary protein excretion, the morphology and GBM CSc in PAN, which indicate indirect evidence that superoxide and/or its metabolites are responsible for glomerular injury.

Low-protein diet and xanthine-metabolising enzymes in adriamycin nephrosis

Proteinuria and renal xanthine metabolising enzymes, xanthine oxidase and xanthine dehydrogenase, were evaluated in Adriamycin-treated rats fed standard (21% casein) and low-protein (6% casein) diets. In rats fed a standard diet Adriamycin was associated with increased activities in the kidney of xanthine oxidase and xanthine dehydrogenase and induced massive proteinuria. The pharmacological block of both enzymes by allopurinol and tungsten block of both enzymes by allopurinol and tungsten reduced proteinuria to one-third of the original levels. Rats fed a low-protein diet presented decreased levels of renal xanthine oxidase and xanthine dehydrogenase and were only slightly proteinuric. Finally, rats shifted from a low-protein diet to a normal one developed massive proteinuria in spite of normal or slightly decreased levels of renal xanthine oxidase and xanthine dehydrogenase. We conclude that a low-protein diet is effective in decreasing the levels of xanthine metabolising enzymes that are in part responsible for the renal damage due to Adriamycin. This is not however the unique mechanism by which the low-protein diet protects against the development of proteinuria in Adriamycin nephrosis; other factors must also be hypothesised.

Nonanticoagulant protective effect of heparin in chronic aminonucleoside nephrosis

Aminonucleoside nephrosis progresses over an 18-week period to focal and segmental glomerulosclerosis (FSGS). Whole heparin has been shown to blunt the extent of renal injury in another model of FSGS, renal ablation; however, the precise mechanism of protection has remained uncertain. Since heparin has a variety of physiologic actions unrelated to anticoagulation, we administered three different heparin compounds, each with a distinct profile of biological properties, to groups of rats given a single intravenous dose of puromycin aminonucleoside (PA). In the absence of a prolongation of the activated partial thromboplastin time (aPTT), both whole heparin (WH) and a 7,000- to 11,000-dalton-molecular-weight nonanticoagulant heparin (NAH) ameliorated the functional and histologic abnormalities of chronic aminonucleoside nephrosis as evidenced by significant reductions in 24-hour urine protein excretion while preserving the glomerular filtration rate and blunting the rise in serum creatinine as compared to untreated PA control animals at the conclusion of the study. In addition, the NAH and WH groups exhibited significantly fewer glomeruli with either segmental mesangial proliferative areas or glomerulosclerosis/hyalinosis lesions 18 weeks after PA administration. A fragment of heparin (HF) was ineffective. We conclude that heparin may exert its beneficial effect in chronic aminonucleoside nephrosis through a biologic action, other than anticoagulation, perhaps by inhibition of mesangial cell proliferation.