Endogenous asymmetrical dimethylarginine and hypertension associated with puromycin nephrosis in the rat

1. The present experiments were designed to investigate the role of asymmetrical NG,NG-dimethyl-L-arginine (ADMA) in causing hypertension associated with the focal and segmental glomerulosclerosis (FSGS) produced by a single bolus of puromycin aminonucleoside (PAN) and successive injection of protamine for 7 days in rats which had undergone unilateral nephrectomy. 2. After the unilateral nephrectomy, and administering PAN and protamine, histological examinations of the kidney revealed a typical FSGS, that is, evident abnormalities including segmental mesangial proliferation, obliteration of glomerular capillary lumens and adhesions between the glomerulus and Bowman's capsule could be observed. Changes in the glomerular epithelial cells consisted of the swelling with bleb formation. 3. In the FSGS rats, urine volume and urinary protein were significantly (P<0.05 and P<0.005) increased throughout 4-week experimental period, while the creatinine clearance was significantly (P<0.005) and transiently decreased, and recovered 4 weeks later. These changes were associated with the sustained elevation of the systolic blood pressure. 4. ADMA levels in aortic endothelial cells, plasma and urine were significantly (P<0.05 and P<0.005) increased in the FSGS rats, but the level in the kidney remained unchanged. 5. The basal level and net production of cyclic GMP in the aortic vessel wall with endothelium when stimulated by norepinephrine and acetylcholine were significantly (P<0.05 and P<0.01) attenuated in the FSGS rats. 6. There were significant and positive correlations between systolic blood pressure (y) and ADMA levels (x) in endothelial cells (y=4.43x+122.2, r=0.979, P<0.0001), plasma (y=0.10x+71.9, r=0.921, P<0.001) and urine (y=0.48x+126.9, r =0.699, P<0.005), but not significant in the kidney (y=0.06x+102.7, r=0.252, NS). 7. These findings suggest that ADMA as an endogenous inhibitor of NO synthesis may play an important role for the pathogenesis in the hypertension associated with the experimental FSGS in the rat.

Antineutrophil cytoplasmic antibody-positive crescentic glomerulonephritis associated with propylthiouracil therapy

A teenage girl with crescentic glomerulonephritis had antineutrophil cytoplasmic antibody (ANCA) detected after she had received propylthiouracil (PTU) for hyperthyroidism without cutaneous vasculitis. ANCA was detected on admission; renal biopsy showed crescentic glomerulonephritis with focal necrotizing glomerulonephritis but no immune deposits. Administration of steroid and decreasing the dose of PTU produced a good clinical response and the ANCA disappeared. It was concluded that ANCA is closely related to the pathogenesis of crescentic glomerulonephritis and that treatment with PTU appeared to induce ANCA.

Different effect of estrogen administration from castration on glomerular injury in unilaterally nephrectomized male Sprague-Dawley rats

We have already reported an equally attenuating effect of castration or estrogen administration on the development of focal segmental glomerulosclerosis (FSGS) in the animal models of a short-term experimental period ended at 24 weeks. In the present study, to clarify the importance of the experimental period in studying the pathogenesis of the development of FSGS, we investigated a long-term effect of castration or estrogen administration on FSGS using an experimental model of uninephrectomized Sprague-Dawley (SD) rats ended at 54 weeks. Thirty male SD rats received unilaterally right nephrectomy at 6 weeks of age. They were divided into three groups: group 1 was control; group 2 was castrated at 6 weeks, and group 3 was administered 0.2 mg estrogen subcutaneously once a month from 6 weeks of age. Body weight, urinary protein, serum albumin and other serum constituents were investigated every 12 weeks from 18 to 54 weeks of age. Each group was studied morphologically at the end of the experiment. Castration attenuated glomerular injury to the same extent as seen in the study of a short-term experimental period, while estrogen administration failed to attenuate glomerular injury, although each treatment equally suppressed an urinary excretion of a sex-related low-molecular-weight (LMW) protein. Castration reduced significantly kidney weight (KW), glomerular volume (GV) and serum growth hormone (GH) levels, but estrogen treatment failed to reduce KW and GV, and conversely elevated GH levels. These results suggest that a sex-related LMW protein influenced by castration or estrogen treatment may not play an important role in the development of FSGS and that an increase in plasma GH levels may contribute to the failure of an attenuating effect of estrogen on glomerular injury.

The ovaries attenuate the aggravating effect of testosterone on glomerular injury in Adriamycin-induced nephropathy of female rats

To clarify whether the ovaries have a potential to attenuate the aggravating effect of testosterone (T) on glomerular injury, we investigated the effect of T in female rats with or without ovaries, using Adriamycin (ADR)-induced nephropathy in female Sprague-Dawley rats. Group 1 consisted of female control rats, group 2 received T, groups 3 and 4 were subjected to ovariectomy (OVX) at 5 weeks of age, and group 4 received further T treatment. Group 5 consisted of male control rats. T was injected subcutaneously every 4 weeks from 5 weeks of age through the end of the experiment. ADR 2 mg/kg was administered intravenously to all rats twice, at 8 weeks of age and 20 days later. Body weight, blood pressure, urinary protein and serum constituents were investigated every 4 weeks from 4 through 24 weeks after the second ADR injection. Each group was studied morphologically 24 weeks after the second ADR injection. Treatment with T or with OVX and T significantly increased the urinary protein excretion. OVX had no significant effect on the urinary protein excretion. Treatment with either T or OVX did not induce any significant effects on the renal function with regard to blood urea nitrogen (BUN), serum creatinine (Cr) and Cr clearance (Ccr) levels, but a combined treatment with OVX and T significantly lowered the serum albumin levels, increased the levels of BUN and Cr and lowered the Ccr values. The glomerulosclerosis index was significantly and markedly higher in control male rats than in control females. Treatment with T resulted in a slight but significant increase in glomerular injury to levels similar to those seen in ovariectomized rats. Combined treatment with OVX and T significantly aggravated glomerular injury in a somewhat accelerated manner, associated with a significant increase in glomerular tuft volume. Our results suggested that the ovaries could not completely suppress glomerular injury worsened by T administered at serum levels similar to those of male rats, but they had a potential to attenuate glomerular injury induced by T, and the protective effect of the ovaries on glomerular injury may be related to their attenuating effect on glomerular growth.

Supplementation with L-2-oxothiazolidine-4-carboxylic acid, a cysteine precursor, does not protect against lipid peroxidation in puromycin aminonucleoside-induced nephropathy

Lipid peroxidation in the kidney has been shown to precede proteinuria in puromycin aminonucleoside (PAN)-induced nephropathy. The aim of this study was to determine if L-2-oxothiazolidine-4-carboxylic acid (procysteine) would protect rats against PAN-induced nephrotoxicity. Male Sprague-Dawley rats were treated with procysteine (16 mg/100 g body weight i.p.) 24 h and 30 min prior to receiving a single injection of PAN (15 mg/100 g body weight i.v.) followed by procysteine in the drinking water (4 g/l). Control rats received procysteine alone (intraperitoneally and in drinking water) or PAN alone and then plain water. Proteinuria was not significantly different between PAN/ procysteine and PAN groups, reaching a maximum at day 14 and persisting at day 28. Lipid peroxidation was more severe in PAN/procysteine rats reaching a maximum at day 3 (253 +/- 30 ng/mg protein) compared to day 5 in PAN rats (196 +/- 20 ng/mg protein). Procysteine alone did not modulate proteinuria over 28 days or lipid peroxidation over 7 days. GSH levels over 7 days were not elevated by procysteine and were virtually zero in PAN and PAN/procysteine rats. Focal glomerulosclerosis (FGS) was worse at day 28 in PAN/procysteine rats than in PAN rats (39 +/- 8.2 vs. 23 +/- 4.5%; p < 0.05). This study shows that procysteine as a potential source of reducing equivalents does not protect against renal lipid peroxidation and FGS in this model. On the contrary, PAN/procysteine rats developed significantly more FGS through yet unknown mechanisms.

Cyclosporine induces glomerulosclerosis: three-dimensional definition of the lesions in a rat model of renal transplant

Previous description of chronic cyclosporine (CsA) renal toxicity commonly included vascular changes, tubular atrophy, and interstitial fibrosis. Glomerular injury was only occasionally documented and it is not clear whether glomerular changes may have an impact on the clinical syndrome of CsA toxicity observed in experimental animals and humans. At the moment the prevailing view is that when patients given CsA have glomerular lesions at a renal biopsy, these were due to concomitant chronic rejection or renal hypoperfusion rather than to CsA itself. As a follow-up of our previous work on the subject (abstract; J Am Soc Nephrol 2:1398, 1992) the present study was undertaken to clarify whether CsA is a direct cause of glomerular injury. We used a model of renal transplant among Lewis rats to better mimic the condition in which CsA is given to humans. Animals underwent kidney isografts and were given daily CsA or vehicle for as long as 12 months. At the end of the experiment specimens of renal tissue were analyzed by a serial section morphometric analysis technique, which allows precise evaluation at the individual glomerular level, glomerular volume and percentage of the capillary tuft affected by sclerosis. Among 85 glomeruli from CsA-treated rats, examined by three-dimensional morphometric analysis, only 12% were normal and 88% revealed segmental sclerosis. Data of single-section analysis compared with three-dimensional morphometric reconstruction showed that the former markedly underestimated the extent of glomerular injury. By three-dimensional analysis we showed that chronic CsA administration was associated with profound changes in glomerular capillary tuft volume distribution as compared to normal. Specifically, a subset of smaller than normal glomeruli emerged in CsA-treated animals in addition to a population of glomeruli which were larger than normal. No significant correlation was found between capillary tuft volume and sclerosis volume. These findings indicate that chronic administration of CsA induces in rats glomerular lesions comparable to the ones reported in human renal or heart transplant. Our present model may help investigating the mechanism(s) of chronic CsA renal toxicity, and will provide important clues for pharmacological manipulations aimed at reducing the long-term consequences of CsA on the kidney.

Endothelin is a key modulator of progressive renal injury: experimental data and novel therapeutic strategies

1. Glomerulosclerosis and tubulointerstitial damage are common histological abnormalities of many renal diseases that progress to end-stage renal failure. 2. In some models of renal damage, glomerulosclerosis seems to be associated with increased glomerular capillary pressure. 3. Due to the positive correlation of glomerulosclerosis and proteinuria in both experimental models and in humans, abnormal permeability to macromolecules has also been considered a possible determinant of glomerulosclerosis. 4. Abnormally filtered macromolecules have an intrinsic toxicity to the kidney due to protein over-reabsorption, possibly leading to tubulointerstitial damage. 5. Endothelin-1 (ET-1) is a vasoconstrictor peptide that induces mitogenesis and the accumulation of matrix proteins by mesangial cells. 6. Evidence is available that ET-1 plays a role in progressive renal disease in different experimental models, including renal mass reduction, lupus nephritis, streptozotocin-induced diabetes and puromycin-induced nephrosis.

Participation of endothelial cells in the development of glomerulosclerosis: a study on murine serum sickness nephritis with mitomycin C

To investigate the participation of endothelial cells in glomerulosclerosis, the study was performed in serum sickness nephritis (SSN) with administration of mitomycin C (MMC). SSN was induced in 8 week male Fisher rats by sensitizing them with albumin, chicken egg (EA). Then MMC (0.5 mg/kg bodyweight) was injected daily for 3 days and they were killed at 1, 2, 4 and 6 week intervals. Significant mesangial expansion and sclerosis were observed in the experimental mixed SSN-MMC group in comparison to the SSN or MMC control group from 1 week to 6 weeks (P < 0.05). Moreover at 1 week, double contour appearance of the glomerular capillary wall, basement membrane splitting and disruption were observed light microscopically in the mixed SSN-MMC group. Electron microscopy revealed peripheral capillary basement membrane disruption with huge subepithelial, mesangial osmiophilic deposits and epithelial foot process effacement. At 6 weeks, disappearance of the endothelial cell fenestration and subepithelial basement membrane-like material formation were observed in the MMC group. Based on these results, it is suggested that MMC induced assault on the glomerular endothelial cell produces prominent glomerular capillary basement membrane disruption at the early phase of SSN, resulting in the accumulation of huge subepithelial and mesangial deposits, mesangial cell proliferation, production of the extracelluar matrix component and initiation of glomerulosclerosis.

Short- or long-term effects of a low-protein diet on fibronectin and transforming growth factor-beta synthesis in Adriamycin-induced nephropathy

Increased synthesis and gene expression of fibronectin or transforming growth factor-beta (TGF-beta) have been reported to be involved in the progressive process of doxorubicin hydrochloride (Adriamycin)-induced nephropathy. In the present study, the effects of dietary protein restriction on the synthesis and gene expression of fibronectin or TGF-beta were investigated by immunoprecipitation, Northern blotting, and TGF-beta bioassay in this model after subjects were given either short- or long-term low-protein diets. In the long-term diet experiment, either a normal protein diet (NPD, 20%) or low-protein diet (LPD, 5%) was fed to the Adriamycin rats for 8 weeks after the injection of Adriamycin. An 8-week LPD significantly ameliorated kidney destruction and remarkably reduced the fibronectin synthesis. Furthermore, the significant decreases of the latent TGF-beta secretion and the expression of TGF-beta 1 mRNA were observed in the Adriamycin rats fed an 8-week LPD. In the short-term diet experiment, an NPD or LPD was fed to the Adriamycin rats for 2 weeks at weeks 4, 8, or 16 after the injection of Adriamycin. A 2-week LPD did not ameliorate kidney damage. Although fibronectin synthesis by the renal cortex in the Adriamycin rats was remarkably reduced by a 2-week LPD, there was no significant decrease in the latent TGF-beta secretion in the Adriamycin rats. The mRNA expressions of fibronectin or TGF-beta 1 were not affected by a 2-week LPD in the Adriamycin rats at any stage. In conclusion, decreased fibronectin and TGF-beta synthesis may be one of the mechanisms by which the long-term dietary protein restriction ameliorates kidney damage. On the other hand, a 2-week LPD affected the only fibronectin synthesis, which thus suggested that an LPD might exert a quicker influence on the protein synthesis of fibronectin than on the transcriptional events of fibronectin.

Sex difference in progression of adriamycin-induced nephropathy in rats

To clarify the pathogenesis of focal-segmental glomerulosclerosis, we investigated the sex-related difference and the effect of castration in Adriamycin (ADR) induced nephropathy of Sprague-Dawley rats. At 5 weeks of age, group 1 female and group 2 male rats were sham operated, and group 3 male rats were castrated. ADR 2 mg/kg was intravenously administered to all rats at 8 weeks of age twice at a 20-day interval. Body weight, blood pressure, urinary protein, and serum constituents were investigated every 4 weeks, 4-20 weeks after the second ADR injection. Each group was studied morphologically 12 and 20 weeks after the second ADR injection. ADR induced massive proteinuria in male rats, whereas it induced significantly lower proteinuria in female rats, and castration significantly reduced proteinuria of male rats to an extent equal to the levels seen in female rats. Control male rats had significantly lower serum albumin levels and a significantly greater impairment of renal function (blood urea nitrogen and creatinine levels) than the female rats or the castrated male rats at 20 weeks. The glomerulosclerosis index was significantly higher in control male rats than in female rats, and castration attenuated glomerular injury of male rats to an extent close to the levels seen in female rats, though there was a significant difference in the glomerulosclerosis index between female rats and castrated male rats. The three groups did not differ in blood pressure and plasma somatomedin C and serum growth hormone levels, whereas the plasma testosterone levels were decreased to undetectable in female and castrated male rats, resulting in a reduction of sex-related low molecular weight protein in urine. These observations suggest that sex hormones such as testosterone and estrogen and/or sex-related low molecular weight protein regulated by testosterone and estrogen may play a contributory role in sex differences in the progression of glomerulosclerosis in ADR-treated rats.

Long-term treatment of rats with FGF-2 results in focal segmental glomerulosclerosis

Long-term treatment (8 and 13 weeks) of rats with FGF-2 led to albuminuria and to increase in serum creatinine indicating the development of chronic renal failure. Histologically, the classic picture of focal segmental glomerulosclerosis (FSGS) was found; males were more severely affected than females. Among the early changes podocyte lesions were most prominent. Surprisingly, mitotic figures in podocytes and a considerable fraction of bi(multi)nucleated podocyte profiles were found in treated animals (roughly 16% in males, 8% in females). Since an increase of cell number of podocytes was not evident, we conclude that FGF-2 stimulates podocytes to re-enter the cell cycle and to undergo mitosis (nuclear division). However, podocytes-probably due to their highly differentiated cell shape in the adult-are unable to complete cell division (cytokinesis) resulting in bi- or multinucleated cells; in others cell division may fail totally leading to podocyte degeneration. Most podocytes in FGF-2-treated rats exhibited degenerative changes including cell body attenuation, extensive pseudocyst formation, widespread foot process effacement, as well as detachments from the glomerular basement membrane (GBM). The development of FSGS in this model is very uniform. In the case of podocyte detachments from peripheral capillaries, parietal cells become attached to naked GBM-areas, establishing the nidus for development of a tuft adhesion to Bowman's capsule. Tuft adhesions grow by encroaching of parietal cells onto adjacent capillary loops, resulting eventually in a solid synechia with collapsed capillaries, that is, what represents segmental sclerosis. The distribution of adhesions on the inner surface of Bowman's capsule appeared to be random, including all locations between the vascular and urinary pole. The two main aspects of this study (inability of podocytes to replicate and development of FSGS based on progressing podocyte degeneration) may be part of a vicious cycle. FGF-2 stimulates podocytes to enter cell division thereby conveying them into a hazardous situation. If a podocyte fails and degenerates it cannot be replaced, aggravating the situation for the remaining cells and possibly increasing their predisposition to respond to mitogenic stimuli. Similar mechanisms may constitute the development of FSGS in other experimental as well as human glomerulopathies.

Effects of a low-protein diet on glomerular endothelin family gene expression in experimental focal glomerular sclerosis

1. The present study was designed to assess whether glomerular expression of mRNAs for endothelin-1 and endothelin-3, as well as endothelin receptors A and B is affected by a low-protein diet during the course of focal glomerular sclerosis. 2. Focal glomerular sclerosis was induced in rats by injection of puromycin aminonucleoside on days 0, 27, 34 and 41 in conjunction with unilateral nephrectomy on day 22. Control rats were subjected to nephrectomy or sham operation on day 22. 3. Animals were divided into six groups. In group 1, the puromycin aminonucleoside-injected rats were fed a standard diet containing 22% protein. In group 2, the puromycin aminonucleoside-injected rats were fed a low-protein diet containing 6% protein, which was initiated on the day of the first puromycin aminonucleoside injection. In group 3, the nephrectomized rats without puromycin aminonucleoside were fed a standard diet. In group 4, the nephrectomized rats without puromycin aminonucleoside were fed a low-protein diet. In group 5, the sham-operated rats were fed a standard diet. In group 6, the sham-operated rats were fed a low-protein diet. 4. The percentage of sclerotic glomeruli in group 1 rats increased markedly with time, reaching 77% on day 80. 5. The glomerular mRNA levels for endothelin-1 and endothelin receptors A and B increased significantly as glomerular sclerosis progressed, whereas no endothelin-3 mRNA was detected in the glomeruli of any group. The endothelin-1 production in isolated glomeruli from group 1 increased significantly as glomerular sclerosis progressed.(ABSTRACT TRUNCATED AT 250 WORDS)

Subpressor dose of angiotensin II increases susceptibility to the haemodynamic injury of blood pressure in Dahl salt-sensitive rats

OBJECTIVE

To investigate the effects of subpressor doses of angiotensin II (Ang II) on the progression of renal injuries in Dahl salt-sensitive (Dahl-S) rats with hypertension.

METHODS

Rats were fed a high-salt (4% NaCl) diet and given an Ang II infusion (10 or 50 ng/kg per min, subcutaneously) for 4 weeks.

RESULTS

The plasma Ang II concentration achieved in the high-dose Ang II infusion was lower than that in low-salt (0.3% NaCl) normotensive rats. The Ang II infusion did not affect systolic blood pressure, cardiac hypertrophy or weight of thoracic aorta. However, the high-dose Ang II infusion increased proteinuria by 58%, enhanced the urinary N-acetyl-beta-D-glucosaminase index by 77% and reduced the glomerular filtration rate by 37%. The impaired renal function was associated with a progression of glomerulosclerotic lesions. Neither tubular nor arterial lesions were exacerbated. The infusion did not influence prostacyclin production or urinary cyclic GMP excretion.

CONCLUSION

A subpressor dose of Ang II infusion impairs renal function with progression of glomerulosclerosis, and these alterations may be due to increased susceptibility of the glomerulus in Dahl-S rats to Ang II-induced injuries. Such a mechanism might underlie a predisposition to hypertension-induced organ damage seen in Dahl-S rats with salt-induced hypertension.

In situ hybridization of type I collagen mRNA in puromycin aminonucleoside-induced glomerulosclerosis

In puromycin aminonucleoside (PAN)-induced focal glomerulosclerosis (FGS), the accumulation of type I collagen has been reported to be observed immunohistochemically in the sclerotic area. The present study was designed to identify the cell type involved in the synthesis of type I collagen in glomerulosclerosis. Tissue sections obtained from rat kidneys with PAN-induced FGS were hybridized with digoxigenin-labeled alpha 1(I) collagen anti-sense and sense cRNA probes. Hybridization signals of alpha 1(I) collagen mRNA were mainly detected in adhesive lesions on the glomerular capillary loop, suggesting that alpha 1(I) collagen mRNA-positive cells were visceral or parietal epithelial cells and did not have a mesangial distribution. Signals were also detected in interstitial cells. The alpha 1(I) collagen mRNA expression, however, was not observed in ED-1-positive cells. It is likely that intrinsic glomerular cells and interstitial cells, but not macrophages, synthesize type I collagen in sclerotic glomeruli.

Induction of nodular sclerosis by insulin in rat mesangial cells in vitro: studies of collagen

These studies evaluated the contribution of insulin to the development of the abnormal mesangial matrix that characterizes diabetic nephropathy and is common to mesangial cells in culture. Glomeruli were isolated from a single rat and divided into two aliquots. In one set (SI-MC), the insulin contained in the medium was only that contributed by the fetal calf serum (20%). For the other set, the tissue culture medium was supplemented with 1 microM insulin (SI+MC). Mesangial cell outgrowths from each condition were isolated, cloned, and propagated. At passage 4, mesangial cells were characterized by morphology and cell markers, and compared in terms of composition and appearance of the secreted extracellular matrix. SI-MC grew in nests of cells surrounded by a thin layer of matrix that was rich in collagen IV. In contrast, mesangial cells supplemented with insulin aggregated into macroscopic "hillocks" rich in collagens I and III as described previously. Insulin (1 microM) or IGF-I (0.1 microM) was subsequently added to the medium of SI-MC. Insulin, but not IGF-I, induced a change in culture morphology and collagen accumulation characteristic of SI+MC. In contrast to SI+MC, SI-MC express insulin receptors and at physiologic concentrations insulin is a more potent stimulator of MC proliferation than is IGF-I. Insulin-induced changes in the collagenous composition of the accumulated ECM were directionally correlated with the rate of collagen I synthesis measured by biosynthetic labeling experiments and collagens III and IV as determined by ELISA. These data demonstrate that insulin alters the phenotype of mesangial cells in culture and their expression of interstitial and basement membrane collagens. These observations implicate insulin as a factor in the pathogenesis of mesangial matrix accumulation in diabetic nephropathy. Furthermore, a method for culturing mesangial cells that accumulate an extracellular matrix that is similar in composition to normal mesangial matrix provides a new model system for future studies of mesangial cell biology.

Increased expression of Na+/H+ exchanger in the injured renal tissues of focal glomerulosclerosis in rats

The renal mRNA expression of Na+/H+ exchanger (NHE) and the effects of NHE inhibitor, amiloride, on renal injury were investigated in adriamycin (ADR)-induced glomerulosclerosis model in rats, which progressively developed extensive glomerulosclerosis and interstitial fibrosis. NHE-1 mRNA from the cortex of the ADR rats progressively increased at weeks 4 and 8 and then peaked at week 16, which paralleled with the degree of glomerular sclerosis and interstitial fibrosis. The interstitial fibrosis in the ADR-rats was prevented by a daily administration of amiloride. A simultaneous analysis of the effects of a high salt diet on NHE-1 mRNA expression or renal injury was performed in the ADR rats at weeks 2 and 8. Renal or glomerular hypertrophy was observed in the control or ADR rats fed an 8% NaCl diet at week 2 and 8 compared to a 1% NaCl diet, while the NHE-1 mRNA expression was not up-regulated by an 8% NaCl diet at week 2. At week 8, the NHE-1 mRNA expression or glomerulosclerosis and interstitial fibrosis were enhanced in the ADR rats fed an 8% NaCl diet compared to a 1% NaCl diet. This histological aggravation by an 8% NaCl diet was prevented by a daily administration of amiloride but not by furosemide. In conclusion, the increased NHE-1 mRNA expression and the preventive effects of amiloride on the renal lesions suggest a potential importance of NHE in the progressive process of ADR-nephropathy. The high salt diet had a hypertrophic and destructive effect on kidney or glomeruli in the ADR rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Time course study of the extracellular matrix in puromycin-aminonucleoside-induced glomerulosclerosis

The purpose of this study was to investigate the mechanism of glomerulosclerosis, which is an important histopathological feature of various renal diseases. Puromycin aminonucleoside (PAN) was administered to rats to produce glomerular lesions, and the kidneys were examined by repeated renal biopsy with light microscopy and immunohistochemical detection of glomerular extracellular matrix (ECM) components (laminin, fibronectin, type I, III, and IV collagen). Immunohistochemical studies utilizing the streptavidin-biotin method showed marked accumulation of laminin and type IV collagen in the adhesions between the glomerular epithelium and Bowman's capsule, as well as in the mesangial matrix. Fibronectin was detected in the normal mesangium and the basement membrane of Bowman's capsule, while adhesions and the matrix accumulations were also positive. The sclerotic lesions of the glomeruli were also stained for type I and III collagen, which exist in normal interstitial tissue, but never in healthy glomeruli. Type I collagen appeared in the lesions after type III collagen. All of the ECM components examined in this study were present in advanced glomerulosclerosis and showed distinctive patterns of progression. These finding suggest that abnormal accumulation and production of ECM components in the glomeruli may have a role in the development of glomerulosclerosis.

Angiotensin converting enzyme inhibitor modulates glomerular function and structure by distinct mechanisms

Rats with puromycin aminonucleoside (PAN) nephrosis were given either angiotensin I converting enzyme inhibitor (ACEI), angiotensin II type 1 receptor antagonist (Ang IIRA), or no treatment for four weeks and were then monitored for an additional 12 weeks. In untreated PAN rats, proteinuria reached a maximum at two weeks (271 +/- 38 mg/day). Proteinuria in this early phase was markedly attenuated by ACEI (96 +/- 35 mg/day, P < 0.01), but unaffected by Ang IIRA (306 +/- 34 mg/day). Acute administration of a bradykinin antagonist substantially dampened the antiproteinuric effect of ACEI in PAN rats, resulting in an average increase in proteinuria of 41 +/- 14% in ACEI-treated rats (P < 0.05, ACEI vs. ACEI+bradykinin antagonist). Acute phase therapy for four weeks with ACEI or Ang IIRA did not attenuate subsequent glomerulosclerosis. Separate groups of PAN rats with similar degree of glomerulosclerosis, assessed at 16 weeks after PAN by renal biopsy, were then treated as follows: ACEI [50 mg/liter drinking water (DW), or 200 mg/liter DW], Ang IIRA (20 mg/liter DW, or 80 mg/liter DW) or no treatment, starting after renal biopsy. Whereas glomerulosclerosis increased from biopsy to autopsy at 28 weeks with emergence of low grade proteinuria in untreated PAN rats, proteinuria was absent and glomerulosclerosis was ameliorated or reversed in ACEI and Ang IIRA groups. The results indicate that the early phase proteinuria of PAN nephropathy is independent of Ang II, and that the antiproteinuric effect of ACEI is, at least in part, channeled through activation of bradykinin, whereas the subsequent progression of glomerulosclerosis is caused by a mechanism involving endogenous Ang II actions.(ABSTRACT TRUNCATED AT 250 WORDS)

TGF-beta 1 in glomerulosclerosis and interstitial fibrosis of adriamycin nephropathy

The role of transforming growth factor-beta 1 (TGF-beta 1) for renal injury was investigated in the chronic model of progressive renal disease in rats induced by the injection of adriamycin. The renal cortical tissues were sampled at weeks 4, 8 and 16 for histological examination, either cortical or glomerular cell culture, and RNA extraction. A progressive increase in fibronectin synthesis was found in metabolically labeled cortical or glomerular culture at week 8 or 16, correlating with the degree of glomerulosclerosis and interstitial fibrosis. TGF-beta bioassay (mink lung epithelial cell assay) showed a progressive increase in latent TGF-beta secretion from cortex and glomeruli, while the amount of active TGF-beta was small. The peak of latent TGF-beta levels at week 16 coincided with the intense TGF-beta 1 staining of inflammatory cells dispersed in the interstitium and glomeruli. Northern blotting demonstrated the difference in the mRNA expression patterns of TGF-beta 1 and latent TGF-beta 1 binding protein (LTBP) in the cortex. TGF-beta 1 mRNA was constantly high throughout the experiment, while LTBP mRNA increased progressively and reached a peak at week 16. Furthermore, mRNA levels of fibronectin, procollagen alpha 2(I), and TGF-beta type II and type III receptors increased progressively in a similar pattern to the renal histological changes. These temporal and spacial relationships between the renal histological changes and the increased expression of TGF-beta 1 and TGF-beta receptors may thus suggest that TGF-beta 1 plays an important role in the process of the renal fibrosis and sclerosis.

A new single nephron model of focal and segmental glomerulosclerosis in the Munich-Wistar rat

The hypothesis that damage to the visceral epithelial cell plays a central role in the pathogenesis of focal and segmental glomerulosclerosis was tested by injecting saponin solutions of increasing concentration (0.1, 0.3, 0.6 and 1.0 mg/ml) in Bowman's space of superficial glomeruli in the Munich-Wistar rat. The microinjections were performed both with and without intermittent clamping of the renal vessels during two minutes. After 8 to 14 days the injected glomeruli were examined by light microscopy. The injected glomeruli were classified as, normal (NL), showing visceral epithelial cell damage (VECD), showing focal and segmental glomerulosclerosis (FSGS) or showing global sclerosis (GS). Swelling and intracellular vacuolation of the visceral epithelial cells (VEC) were considered as VECD. FSGS-lesions were seen most frequently in the glomeruli injected with 10 nl of a saponin solution with a concentration higher than 0.3 mg/ml. In view of the light microscopic lesions four glomeruli in a 0 mg/ml, the 0.1 mg/ml and the 0.6 mg/ml saponin groups were examined after 40 minutes with transmission electron microscopy (TEM) to evaluate the selectivity of the lesions. In the 0 and 0.1 mg/ml group only occasional limited fusion of the foot processes of the podocytes was seen. In the 0.6 mg/ml group segmental lysis of the VEC without ultrastructural damage to the capillary basement membrane or the endothelial and mesangial cells was seen. It is concluded that it is possible to induce direct segmental lysis of the visceral epithelial cells in a single glomerulus, and that this damage to the visceral epithelial cells is related to the development of focal and segmental glomerulosclerosis.

Reduction of urine volume ameliorates adriamycin-induced nephropathy

1. Adriamycin, a commonly used antineoplastic antibiotic, induces glomerular lesions in rats, resulting in persistent proteinuria and glomerulosclerosis. 2. The effect of urine volume on the progression of adriamycin-induced nephropathy was studied in 70 male Wistar rats (180-200 g) observed for 30 weeks and separated into 4 groups: healthy control group (HCG, N = 10) inoculated i.v. with 1 ml of saline, and nephrotic groups inoculated iv with a single dose of adriamycin of 3 mg/kg body weight. The nephrotic rats were separated into 3 groups (N = 20): nephrotic control group (NCG) receiving only adriamycin; dehydrated nephrotic group (DNG) water deprived for 36 h within each 48-h period, and furosemide nephrotic group (FNG) treated with 12 mg/dl furosemide, and 0.9 g/dl NaCl in the drinking water. 3. The 30-week survival rates of the DNG (100%) and HCG (100%) were significantly higher than those of the NCG (85%) and FNG (55%). 4. The proteinuria observed in the HCG (range, 7.38 +/- 0.7 to 13.6 +/- 1.27 mg/24 h) was significantly lower than that observed for all the nephrotic groups throughout the experiment. The DNG presented significantly less proteinuria (range, 42.71 +/- 6.83 to 140.10 +/- 19.22 mg/24 h) than the NCG (range, 35.32 +/- 7.64 to 250.00 +/- 25.91 mg/24 h) from week 10 on. There was no significant difference between the mean 24-h proteinuria of the NCG (range, 35.32 +/- 7.64 to 250.00 +/- 25.91 mg/24 h) and the FNG (range, 35.82 +/- 7.91 to 221.54 +/- 26.74). 5. The mean frequency of damaged glomeruli was 0.3% +/- 0.3 for HCG, 42% +/- 6% for CNG, 40.8% +/- 8% for DNG, and 47% +/- 14% for FNG. The median value of the tubulointerstitial lesion, evaluated by a semiquantitative method, was 0 in HCG, 10 in CNG, 8.5 in DNG and 9.5 in FNG (P < 0.05 for all groups compared to HCG). 6. The data indicate that reduction of urine volume has a protective effect on adriamycin-induced nephropathy.

Systemic lupus erythematosus-like syndrome with focal proliferative glomerulonephritis during D-penicillamine therapy

We report a patient with RA who developed serological evidence for lupus disease in the presence of a crescentic immune complex glomerulonephritis (GN). This occurred after 4 years therapy with penicillamine and resolved on withdrawal of this drug and following treatment with cyclophosphamide.

The histopathological changes associated with allograft rejection and drug toxicity in renal transplant recipients maintained on FK506. Clinical significance and comparison with cyclosporine

The histopathological changes in 51 renal allograft biopsies from patients immunosuppressed with FK506 were compared with those seen in 30 needle biopsies obtained from patients on cyclosporine. The frequency and severity of rejection episodes were similar in both groups. Tubular vacuolation and myocyte vacuolation were found to be useful morphological markers to monitor short-term drug toxicity associated with both drugs. Long-term administration of FK506 led to striped interstitial fibrosis and arteriolar hyalinosis, similar to that previously documented for cyclosporine. One case each of hemolytic uremic syndrome and necrotizing arteriopathy was noted in patients receiving FK506. FK506 and cyclosporine are structurally unrelated compounds; hence the parallelism observed in their nephrotoxicity profile suggests that the interactions of these drugs with renal tissue involves the operation of two different initial signal-transducing mechanisms, ultimately activating the same final metabolic pathways.

Effects of enalapril on adriamycin-induced nephrosis

Adriamycin induces proteinuria and glomerular changes in rats similar to those found in human focal segmental glomerulosclerosis (FSGS). Progression of this lesion may be slowed by use of angiotensin converting enzyme inhibition. To evaluate this we injected two groups of Sprague-Dawley rats with Adriamycin (2 intravenous doses of 2 mg/kg given at an interval of 3 weeks). One group of rats received enalapril (50 mg/l) in their drinking water. Control rats were injected with saline. After 28 weeks, the mean whole kidney glomerular filtration rate was significantly less and proteinuria and sclerotic index were significantly greater in rats receiving adriamycin compared with controls (P < 0.05). Administration of enalapril did not decrease proteinuria (545 +/- 398 mg/day vs 494 +/- 325 mg/day, P >0.05) or improve the glomerular filtration rate (0.31 +/- 0.18 ml/min per g kidney weight vs 0.41 +/- 0.21 ml/min per g, P = 0.27). However, treatment with enalapril significantly reduced the mean glomerular sclerotic index compared with untreated rats (1.62 +/- 0.88 vs 0.82 +/- 0.49, P = 0.05). Enalapril may be beneficial in preserving glomerular structure in this experimental model of FSGS.

Protective effect of benidipine against the development of glomerular sclerosis in experimental nephrotic syndrome

An experimental focal segmental glomerular sclerosis (FSGS) was induced by the combined administration of puromycin aminonucleoside (PAN) and protamine sulfate (PS). Blood collections were made on days 0, 37, 70 and 94. Urine collections were made on days 0, 24, 80 and 94. Vehicle-treated rats showed severe proteinuria and an increase in serum total cholesterol (sTC). Benidipine (1 or 3 mg/kg, p.o.)-treated rats exhibited less proteinuria and lower sTC than the vehicle-treated rats. On days 70 and 94, both blood urea nitrogen (BUN) and serum creatinine (sCR) values in the vehicle-treated rats were significantly higher than those in normal rats (without treatment with PAN and PS). On the other hand, the treatment with benidipine (1 or 3 mg/kg, p.o.) attenuated the increases in BUN and sCR. On day 94, vehicle-treated rats showed a significant decrease in creatinine clearance as compared with normal rats, but benidipine (1 or 3 mg/kg, p.o.)-treated rats did not. The histology was examined on day 94. Vehicle-treated rats demonstrated a significantly greater percentage of glomeruli with segmental areas of glomerulosclerosis/hyalinosis, mesangial cell proliferation, and mesangial foam cell. Benidipine (3 mg/kg, p.o.) ameliorated the development of renal regeneration as estimated by histological examination. These results suggest that the Ca-channel blocker benidipine is a favorable drug for preventing the progression of glomerular sclerosis.

[The effect of elastase on aminonucleoside nephrosis--on renal vascular system]

This study was performed to investigated the relationship between cross sectional areas of glomerular arterioles and glomerular volume in rats with puromycin aminonucleoside (PAN)-induced nephrosis, which is an experimental model of glomerular sclerosis. We also evaluated the effect of an anti-arteriosclerotic agent, elastase on these parameters. Six-week-old male Sprague-Dawley rats were divided into 3 groups; control, PAN-treated (70 mg/kg i.p.), or PAN+elastase-treated (5 mg/kg/day i. m.) group. After 12 weeks of experimental period, microvascular cast of the kidney was prepared, and the cross sectional areas of afferent and efferent arterioles as well as glomerular volume were measured using scanning electron microscopy. In the juxtamedullary glomeruli with minor abnormalities, the efferent arteriole was narrower in PAN-treated rats than in the control rats and the elastase-treatment partially corrected it (control 55.7, PAN 35.9, PAN+elastase 43.7 x 10 microns 2). On the other hand, the cross sectional area of afferent arteriole was not different among the 3 groups. In glomeruli showing sclerosis, the cross sectional area of efferent arteriole correlated positively with the glomerular volume. There results suggest that constriction of the efferent arterioles contributes to the development of glomerular sclerosis in PAN-induced nephrosis. In addition, elastase possibly inhibits this process and thereby protect glomeruli from sclerosis.

Long term effects of morphine on mesangial cell proliferation and matrix synthesis

Since focal glomerulosclerosis is the predominant glomerular lesion in heroin nephropathy and since mesangial expansion is considered to be a precursor of glomerulosclerosis, we have evaluated the effect of opiates on mesangial cell (MC) proliferation and matrix synthesis. We showed, using a fluorometric assay, that MC are not capable of metabolizing heroin to its active metabolite morphine. Cells exposed to morphine (10(-5) M or 10(-4) M) in prolonged cultures either continuously (Group A) or intermittently (Group B) showed enhanced incorporation of [3H]thymidine when compared to control cells (control, 88600 +/- 26303 cpm/well vs. morphine 10(-4) M-Group A, 321203 +/- 52867, P less than 0.001; control vs. morphine 10(-4) M-Group B, 223126 +/- 46866 cpm/well, P less than 0.01; control, 107593 +/- 42284 cpm/well vs. morphine 10(-5) M - Group A, 267108 +/- 41866 cpm/well, P less than 0.001; control vs. morphine 10(-5) M - Group B, 202317 +/- 24325 cpm/well, P less than 0.05). However, MC incubated with a lower concentration of morphine (10(-6) M) enhanced DNA synthesis when exposed intermittently only (control, 107593 +/- 42284 cpm/well vs. Group B, 219164 +/- 15552 cpm/well, P less than 0.05). This growth stimulating effect of morphine (10(-6) M and 10(-5) M) was also observed at earlier time points, that is, one- and one-and-a-half-week old cultures. However, in one-week-old cultures. morphine in a higher concentration (10(-4) M) showed a suppressive effect (P less than 0.05) on MC proliferation (morphine, 3620 +/- 220 cpm/well vs. control, 4668 +/- 410 cpm/well). This effect not only subsided by one and a half weeks but morphine (10(-4) M) treated cells enhanced MC proliferation. An opioid antagonist, naloxone attenuated the effect of morphine in one and half week old cultures. Morphine at 10(-6) M to 10(-4) M concentrations enhanced incorporation of [3H]proline in the extracellular proline pool (a component of mesangial matrix) when compared to control (control, 309661 +/- 3992 vs. morphine 10(-4) M, 363104 +/- 10539 cpm/well, P less than 0.05 or morphine 10(-5) M, 397954 +/- 31008 cpm/well, P less than 0.001 or morphine 10(-6) M, 384630 +/- 26369 cpm/well, P less than 0.01). In addition, MC incubated with morphine (10(-6) M and 10(-4) M) also enhanced (P less than 0.001) synthesis of laminin.(ABSTRACT TRUNCATED AT 250 WORDS)

Albuminuria is not an aggravating factor in experimental focal glomerulosclerosis and hyalinosis

It is widely known that the severity of glomerular sclerosis is proportional to the degree and chronicity of proteinuria and that the degenerative changes of glomerular epithelial cells that are associated with overflow albuminuria can be experimentally induced by the injection of large quantities of heterologous albumin. Such evidence suggests that autologous albuminuria per se may have a harmful effect on the kidneys. To examine the cause and effect relationship between renal lesions and albuminuria, we produced Adriamycin-induced experimental focal glomerular sclerosis in Nagase analbuminemic (NA) rats and control Sprague-Dawley (SD) rats and observed both the renal functional and histologic changes for 20 weeks. At week 4 after injection of Adriamycin glomerular epithelial lesions including foot process fusion were similarly revealed by an electron microscopic study in both groups in spite of the presence of a large difference in the amount of proteinuria (SD rats: 491 +/- 84 mg/day, NA rats: 43 +/- 30 mg/day) and albuminuria (SD rats: 383 +/- 73 mg/day, NA rats: 2 +/- 1 mg/day). At week 20, a light microscopic study showed the same degree of glomerular sclerosis and hyalinosis and tubulointerstitial changes associated with a decrease in inulin clearance in both groups. The increased glomerular accumulation of immunoglobulin M or complement 3 and glomerular trapping of aggregated human immunoglobulin G were also similar between the SD and NA groups. In summary, renal destruction of Adriamycin-nephropathy was not dependent on the degree of albuminuria. These results suggest that albuminuria is not an aggravating factor in focal glomerulosclerosis.

Rapid induction of glomerular lipidosis in APA hamsters by streptozotocin

The pathology of male Syrian hamsters of APA strain which were injected intraperitoneally with 40 mg/kg body weight of streptozotocin (SZ) at 2 months of age was examined. It showed long-lasting prominent hyperglycaemia and hyperlipidaemia with glucosuria and the development of glomerular lipidosis from 1 month after SZ-injection (1 MAI). Glomerular lesions were restricted to the juxtamedullary cortex at 1 MAI and then extended to the subcapsular cortex. At 3 MAI, glomerular lesions were characterized by focal segmental glomerulosclerosis showing segmental expansion of the mesangial area due to an increase of basement membrane-like material and mesangial cells with lipid droplets and foam cells. SZ-induced diabetic APA hamsters will be a useful model for the investigation of glomerular lipidosis and focal segmental glomerulosclerosis.

Autoantibodies to leucocyte antigens in hydralazine-associated nephritis

Clinical and laboratory findings and drug history were studied in 17 patients with suspected hydralazine-associated nephritis, five of whom only had renal disease, while twelve also had extrarenal manifestations. Renal biopsies revealed extracapillary proliferative or focal segmental proliferative glomerulonephritis in 10 patients, and tubulo-interstitial nephritis in five patients. Antinuclear antibody (ANA) was found in 16 patients, but none of the 14 patients tested had antibodies to DNA. Tests for antibodies to myeloperoxidase (anti-MPO) and antibodies to neutrophil cytoplasm antigen (ANCA) were performed by ELISA. Twelve of the 14 patients tested had anti-MPO; five of these 14 patients had ANCA, while one had borderline levels. These findings suggest that hydralazine facilitates the induction of a systemic disease with multiple autoantibody production.

Glomerular morphometry of adriamycin-induced focal and segmental glomerulosclerosis in the rat

The present paper presents a morphometric study of the evolution of the glomerulus in Adriamycin-induced focal and segmental glomerulosclerosis in the rat over 32 weeks. The morphometric parameters studied generally varied significantly when the groups treated with Adriamycin were compared with controls. Glomerular area and perimeter showed an irregular pattern and finally ended up with values similar to those of the control group. Glomerular capillary tuft area and perimeter were always significantly greater in Adriamycin-treated groups than in controls. The mesangial area of treated animals increased over the study period in comparison with that of controls. While the total number of cells in the glomerular capillary tuft had an irregular pattern, the proportion of cells in relation to glomerular capillary tuft area was significantly lower in treated animals than in controls.

Intraglomerular proteinase activity in adriamycin-induced nephropathy

Adriamycin (ADR)-induced nephropathy is characterized by focal and segmental glomerulosclerosis and is supposed to be an ideal model of chronic progressive renal disease. The aim of our study was to investigate whether there might be an altered activity of glomerular proteinases in ADR nephropathy, thereby aggravating glomerular protein accumulation as an important initiating hallmark of glomerulosclerosis. In fact, we could demonstrate significantly enhanced levels of intraglomerular protein and DNA content in the experimental animals at week 7, 12 and 22 after administration of ADR. When relating intraglomerular proteinase activity, which was measured in ultrasonically destroyed isolated glomeruli, obtained by differential sieving techniques, to the intraglomerular protein and DNA content, this enzyme activity was significantly reduced throughout the observation period. Based on these data, we suggest that this relatively decreased proteinase activity in glomeruli exposed to ADR might play a pathogenetic role in the development of glomerular hypertrophy, an important harbinger of glomerulosclerosis.

Long-term effects of mild oligonephronia induced in utero by gentamicin in the rat

Renal clearance studies and morphologic observations were performed in rats aged 14, 21, and 28 d and 3, 6, 9, and 12 mo born with a 20% reduction in nephron number after administration of 75 mg/kg/d of gentamicin to their mothers during the second half of gestation. Gentamicin was still present in urine 3 mo after birth. Morphologic damage characteristic of gentamicin accumulation was observed in the kidney on d 14 and 21. Adequate compensatory adaptation to oligonephronia occurred for glomerular function within 14 d of birth, but tubular phosphate reabsorption was significantly low on d 21. On d 28, no evidence of histologic or functional damage to the kidney was observed. At 3 mo, mesangial lesions were observed in rats of the gentamicin group, whereas they were rarely present in 6-mo-old control rats. Furthermore, glomerular sclerotic lesions were already evident in about 5% of the juxtamedullary nephrons. The same percentage of injured nephrons was not observed before 12 mo in controls. Complementary morphologic data obtained in 24-mo-old rats showed that glomerulosclerosis involved 40% of the juxtamedullary nephron population at this age in animals of the gentamicin group versus 21% in controls. It is concluded that in the young rats born with oligonephronia of gentamicin-treated mothers neither the gentamicin remaining in the kidney cells nor the injuries it caused them prevented compensatory adaptation of the kidney to a reduced number of nephrons. However, although this oligonephronia was mild, it might have been sufficient to cause early development of glomerular sclerosis in the adults.

Decreased anionic sites in different portions of the basement membrane in aminonucleoside nephrosis

We induced aminonucleoside (AN) nephrosis in male Sprague-Dawley rats and evaluated the decreases in negative charge in the peripheral and proximal portions of the loop basement membrane and the basement membrane in the paramesangial area. Following intravenous injection of polyethyleneimine (PEI), the number of PEI granules per 0.1 micron 2 of the basement membrane, and those per 1 micron length of the lamina rara externa (LRE) and lamina rara interna (LRI) were counted in each portion under an electron microscope and compared with those in the control group. In the rats with AN nephrosis, the number of PEI granules per 0.1 micron 2 was significantly decreased in each portion of the basement membrane. However, the degree of decrease was similar among the 3 portions. The ratio of the numbers of granules in the proximal and paramesangial portions to that in the peripheral portion (peripheral:proximal:paramesangial) was 1:0.89:0.64 in the control group and 1:0.88:0.62 in the AN nephrosis group. Similar results were obtained for the numbers of PEI granules per 1 micron length of the LRE and LRI. These findings suggest that the negative charge is decreased in the loop basement membrane and paramesangial basement membrane in AN nephrosis, but the degree of decrease appears to be uniform.

[Changes in the expression of basement membrane and type I collagen gene in focal glomerular sclerosis (FGS)]

This study deals with the quantification of mRNA of basement membrane components (laminin, type IV collagen, heparan sulfate proteoglycan) and type I collagen in focal glomerular sclerosis induced by the aminonucleoside of puromycin (PAN) in rats. PAN (15 mg/100 g B.W.) was injected intraperitoneally to male Sprague-Dawley rats on day 0. On day 22, the right kidney was removed from group II and III. Rats in group III received injections of PAN (5 mg/100 g B.W.) on day 27, 34 and 41. Rats in group II received injections of 0.9% NaCl instead of PAN. Remnant kidneys were removed on days 48, 60 and 80 and processed for RNA isolation and histopathological study. Glomerular RNAs were isolated using guanidinium thiocyanate and then dotted onto nylon membrane. Filters were hybridized with specific cDNA probes and exposed to film for analysis by densitometer. FGS was detected in 70% of glomeruli on day 80 in group II. All the basement membrane components and type I collagen were accumulated in the sclerotic areas. The mRNA coding for laminin and type IV collagen continued to increase in group III till day 80. The mRNA for HSPG decreased when the urinary protein excretion was maximum on day 48, then increased with the remission of proteinuria. The type I collagen mRNA also increased during the course of the FGS. We suggest that decrease of mRNA for HSPG may play an important role in the development of proteinuria in PAN nephrosis and increase of mRNA coding for laminin, type IV collagen and type I collagen may be involved in focal glomerular sclerosis.

Three-dimensional morphometric analysis of segmental glomerulosclerosis in the rat

In idiopathic nephrotic syndrome, and in experimental models of nephrosis, changes of visceral epithelial cells involve the entire glomerular population while segmental sclerotic changes are reported to affect only a certain number of glomeruli. Because conventional determination of the percentage of glomeruli affected by sclerotic lesions is usually based on the examination of randomly selected sections, we wondered whether glomeruli appearing normal in a given section could be affected by sclerosis in other regions of the capillary tuft (CT). To assess the real incidence and the spatial extension of sclerotic changes at the level of single glomerulus, we used serial-section morphological analysis to measure the volume of the glomerulus and that of sclerosis lesions. In glomeruli from control rats and in glomeruli from adriamycin (ADR) treated rats surface area of Bowman's capsule (BC), CT and sclerotic regions were measured using stereology techniques in all the consecutive sections containing each individual glomerulus, and corresponding volumes were then calculated. Mean volume of BC and CT were not significantly different between control and ADR rats (0.71 +/- 0.03 and 0.53 +/- 0.03 vs. 0.76 +/- 0.04 and 0.53 +/- 0.02 microns 3 x 10(-6), respectively). The distribution of glomerular volume parameters in the ADR rats were more spread out than in control animals, indicating that some glomeruli became smaller while other became larger. No sclerotic changes were found in control rats, while in the three ADR rats 94, 90 and 92% of glomeruli, respectively, were affected by sclerotic lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of 11-deoxycorticosterone-salt-induced glomerular hypertrophy and glomerulosclerosis by dietary phosphate binder

The effects of dietary phosphate binder on deoxycorticosterone (DOC)-salt-hypertensive rats were examined. DOC-treated and non-DOC-treated rats were fed the diet either with or without phosphate binder, dihydroxyaluminum aminoacetate. All rats drank 1% NaCl. DOC-salt-treated rats without binder demonstrated marked glomerular hypertrophy, many globally sclerosed glomeruli, severe proteinuria, focal cardiac fibrosis, and splenomegaly. A significant reduction of glomerular hypertrophy, glomerulosclerosis, severity of proteinuria, splenomegaly, and the myocardial lesion took place when the DOC-salt-treated rats were given phosphate binder. The globally sclerosed glomeruli exhibited remarkable hypertrophy while structurally preserved glomeruli showed little evidence of enlargement. The plasma phosphate level was low in rats with dietary phosphate binder. In conclusion, the dietary phosphate binder ameliorated glomerular hypertrophy, glomerulosclerosis, proteinuria, myocardial fibrosis, and splenomegaly occurring in DOC-salt-treated rats. The data indicated that there was an association between glomerular hypertrophy and glomerulosclerosis in this model. The exact mechanisms of action of the phosphate binder, however, remain far from clear.

Naproxen-induced nephropathy in systemic lupus erythematosus

A 34-year-old female with an 8-month history of systemic lupus erythematosus and intermittent naproxen use presented with acute oliguric renal failure, hypoalbuminemia, 4+ proteinuria, and an active urinary sediment. The clinical picture suggested a rapidly progressive lupus glomerulonephritis. Renal biopsy, however, demonstrated chronic, active interstitial nephritis without evidence of immune deposits by immunofluorescence or electron microscopy. Nonsclerotic glomeruli revealed diffuse foot process fusion without cellular proliferation. These findings were consistent with nonsteroidal anti-inflammatory drug induced nephropathy. Discontinuation of naproxen and institution of corticosteroid therapy was followed by improvement in renal function and remission of nephrotic syndrome. This case represents the first report of nonsteroidal antiinflammatory drug nephropathy associated with systemic lupus erythematosus.

Cisplatin-induced reductions in renal functional reserve uncovered by unilateral nephrectomy: an experimental study in the pig

Groups of mature Large White female pigs, approximately 10 months of age, received single intravenous infusions of 1.5, 2 or 2.5 mg/kg body weight (equivalent to approximately 90, approximately 120 and approximately 150 mg/m2) cisplatin. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured before and at 4 weeks after cisplatin infusion by renography using [99 mTc]-DTPA (diethylenetriamminepentaacetic acid and iodohippurate sodium I 131, respectively. The left kidney of each cisplatin-treated animal plus that of four age-matched control pigs was then removed surgically, and GFR and ERPF were measured in the remaining kidney at 4 weekly intervals for up to 24 weeks after unilateral nephrectomy (UN). The pigs treated with cisplatin exhibited no consistent change in either GFR or ERPF at 4 weeks after treatment. A histological evaluation of kidneys from animals treated with greater than or equal to 2 mg/kg cisplatin that had been removed at UN revealed both tubular and glomerular lesions. The latter consisted of cell proliferation on the parietal surface of the urinary space; damage to the S1 portion of the proximal convolution was also noted. Following UN there was a pronounced dose-dependent reduction in the functional status of the remaining kidney such that the increase in GFR and ERPF in pigs initially receiving 2.5 mg/kg cisplatin was less than 50% of that seen in age-matched UN controls. Moreover, the glomerular lesions observed at 4 weeks after cisplatin infusion had apparently progressed to glomerular hyalinisation by 24 weeks after UN. Thus, prior treatment with cisplatin may cause a permanent reduction in renal functional reserve that may be clinically "silent" until exposure to an additional nephrotoxic insult.

[The effect of the elastase on aminonucleoside nephrosis]

In this paper, we studied the effect of elastase on aminonucleoside (AN) nephrosis which is considered a model of focal glomerular sclerosis (FGS). Elastase is an enzyme which disintegrates elastin, discovered by Balo, and used in the treatment of arteriosclerosis and hyperlipidemia. It has also been known to improve metabolism of acid mucopolysaccharides, so, this study focused on metabolic improvement. Three groups of male Sprague-Dawley rats were studied and observed at regular intervals; 30, 60, 90 days. The ANE group (AN + elastase) was administered one shot of AN (10 mg/100 g B.W.) during the test interval, while elastase (5 mg/kg B.W.) was injected 5 days/week for the entire test interval. The AN group was administered one shot of AN only. The third group was a control (C). The following results were observed: (1) Focal segmental hyalinosis and sclerosis (FSHS); ANE group was weaker than AN group. (2) Other significant qualifying glomerular changes (vacuolar change and hyaline droplets of the epithelial cells, adhesion, and foam cells); ANE group was weaker than AN group. (3) Anion loss in GBM was shown by a lack of colloidal iron staining under light microscopy, and by a lack of PEI particles under electron microscopy; there was significantly less anion loss with ANE group, than with AN group. The findings suggest that elastase has an affect on the metabolism of acid mucopolysaccharide and collagen in sclerotic lesion, and may restrain the progress of amino-nucleoside nephrosis.

[Studies on initiation and progression of focal glomerular sclerosis in rats]

In order to clarify the mechanisms of the initiation and progression of focal glomerular sclerosis (FGS), we investigated changes in the mesangial function or qualitative changes in the extracellular matrix of mesangium in puromycin aminonucleoside (PAN)-induced FGS in rats. At first, we investigated that the relationship between the progression of FGS and mesangial function. In order to evaluate the mesangial function, rats received the i.v. injection of colloidal carbon (C. C.) (20 or 30 mg/100 g). Results obtained from this experiment suggest that the progression of glomerular sclerosis may be related to changes in mesangial function. Furthermore, results suggest that the abnormality of the extracellular matrix may lead to changes in mesangial function and the progression of glomerular sclerosis. Therefore, in the next experiment, the proteoglycans (PGs), one of the components of extracellular matrix, were analyzed by the column chromatography to clarify qualitative changes in the PGs such as the molecular size and charge density. Results obtained from this experiment indicate that the sclerotic glomeruli synthesize the PGs with different molecular size and charge density from normal glomeruli. It is concluded from these experiments that the abnormality of the mesangial function and the synthesis of PGs, the components of the extracellular matrix, may lead to the progression of FGS. Namely, the qualitatively altered PGs may cause abnormal interactions with other components of matrix, which lead to changes in mesangial function, death of mesangial cell and the progression of FGS.

Effect of phosphate binders on the course of chronic renal failure in rats with focal glomerular sclerosis

To investigate the effect of phosphate binders on the progress of renal functional deterioration, aluminium hydroxide (AL) or calcium carbonate (CA) was administered to adriamycin (ADR)-induced progressive renal failure model rats. Urinary protein excretion was reduced in ADR rats treated with AL (ADR-AL group) or CA (ADR-CA group), compared to those without the treatment (ADR group). Urinary phosphate excretion, serum phosphate concentration, and calcium-phosphate product were significantly lower in the ADR-AL and ADR-CA groups than in the ADR group. At week 34, increased serum creatinine, glomerular sclerosis and tubulointerstitial alterations, being marked in the ADR group, were ameliorated in the ADR-AL and ADR-CA groups. However, there was no significant difference in body weight and serum total protein among the three groups. We conclude that AL and CA could both prevent chronic progressive renal deterioration in focal glomerular sclerosis induced by ADR, and preserve the nutritional condition.

Myelofibrosis and focal segmental glomerulosclerosis associated with toluene poisoning

A 60-year-old man with long-term exposure to toluene presented with both myelofibrosis and focal segmental glomerulosclerosis. There was also evidence of other toluene-related complications to support the diagnosis of toluene toxicity. The toxic effects of toluene, particularly kidney disorders and haematotoxicity, suggest a relationship between toluene, myelofibrosis and focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis in patients receiving lithium carbonate

Lithium carbonate is a commonly used psychiatric medication with a number of toxic renal effects, which include nephrotic-range proteinuria. A review of the literature concerning lithium-induced proteinuria is presented and three cases of nephrotic-range proteinuria are described in association with lithium therapy. The pathology in these three cases was focal segmental glomerulosclerosis, a finding not previously described.

Differences in puromycin aminonucleoside nephrosis in two rat strains

Administration of puromycin aminonucleoside (PAN) to Wistar rats induces proteinuria and enhanced mesangial deposition of circulating macromolecules. After proteinuria of longer duration focal and segmental glomerular hyalinosis and sclerosis (FSGHS) develops. The present report analyzes these aspects of PAN nephrosis in PVG/c rats, a strain previously shown to be remarkably resistant to proteinuria and FSGHS with aging or after uninephrectomy. In Wistar rats multiple injections of PAN during five months resulted in sustained severe proteinuria and FSGHS lesions in 8.1 +/- 1.0% (mean +/- 1 SEM) of their glomeruli (N = 6). In PVG/c rats a 1.3-fold higher dose of PAN was needed to induce chronic proteinuria similar to the Wistar rats. After five months 3.3 +/- 0.9% of their glomeruli showed FSGHS (N = 6, P less than 0.01) and the glomerular lesions were considerably less advanced. In acute PAN nephrosis induced by a single intravenous injection of PAN the mesangium of Wistar rats contained large amounts of lipid in contrast to a few small mesangial lipid droplets in nephrotic PVG/c rats. After injection of colloidal carbon in nephrotic PVG/c rats no enhanced carbon accumulation was found in the mesangium when compared to nonproteinuric controls. This result clearly differs from the increased mesangial sequestration of circulating material in nephrotic Wistar, and most other rat strains. The unchanged mesangial traficking of macromolecules in nephrotic PVG/c rats and the low incidence of FSGHS lesions in the presence of sustained glomerular proteinuria may reflect a relative resistance to PAN-induced glomerular damage in this particular rat strain.

The enhancement of aminonucleoside nephrosis by the co-administration of protamine

An experimental model of focal segmental glomerular sclerosis (FSGS) was developed in rats by the combined administration of puromycin-aminonucleoside (AMNS) and protamine sulfate (PS). Male Sprague-Dawley rats, uninephrectomized three weeks before, received daily injections of subcutaneous AMNS (1 mg/100 g body wt) and intravenous PS (2 separated doses of 2.5 mg/100 g body wt) for four days. The series of injections were repeated another three times at 10 day intervals. The animals were sacrificed on days 24, 52, and 80. They developed nephrotic syndrome and finally renal failure. The time-course curve of creatinine clearance dropped and showed significant difference (P less than 0.01) from that of each control group, such as, AMNS alone, PS alone or saline injected. Their glomeruli showed changes of progressive FSGS. The ultrastructural studies in the initial stage revealed significant lack of particles of perfused ruthenium red on the lamina rara externa and marked changes in epithelial cell cytoplasm. Therefore, it is suggested that the administration of PS enhances the toxicity of AMNS on the glomerulus and readily produces progressive FSGS in rats resulting in the end-stage renal disease.