Effects of oral adsorbent in the rat model of chronic renal failure.

The effects of oral adsorbent, AST-120 (Kureha Chemical Ind. Co., Tokyo), were studied in the rat model of subtotal nephrectomy. In 34 female Sprague-Dawley rats, three quarters of the renal mass were removed from the left kidney by ligation of 3 branches of the left renal artery. One week later, the right kidney was removed. Two days after right nephrectomy, control rats were fed standard rat chow ad libitum, while AST-120-treated rats were fed standard rat chow containing AST-120 ad libitum. The animals were observed for 9 weeks. Of the control rats, some became severely ill and appeared to be almost dying before 9 weeks, while paired AST-120-treated rats appeared well. Body weight was maintained better in AST-120-treated rats than in control rats. At completion of the study, levels of BUN and serum creatinine were lower and glomerular filtration rate and renal plasma flow rate were higher in AST-120-treated than in control rats (p < 0.05), although there was no statistically significant difference in proteinuria. Serum uremic peak 2a measured by high-performance liquid chromatography, which is considered to correspond to uremic toxins, was statistically lower in AST-120-treated rats (p < 0.05). Finally, a marked reduction in the degree of glomerular sclerosis was noted in AST-120-treated versus control rats (p < 0.05). The results indicate that AST-120 is effective in the treatment of chronic renal failure in terms of reducing uremic symptoms as well as preserving renal function and glomerular architecture. The data also indicate that a reduction in uremic toxins could delay the progressive damage of renal function and glomerular architecture in chronic renal failure.     

Effects of oral adsorbent AST-120 (Kremezin) on renal function and glomerular injury in early-stage renal failure of subtotal nephrectomized rats

The aim of the present study was to determine if treatment with an oral adsorbent (AST-120, Kremezin) might decrease the urinary albumin excretion and serum indoxyl sulfate (s-IS), and prevent glomerular sclerosis in early-stage renal failure, i.e. 0.9-1.2 mg/dl of serum creatinine (s-Cr) and 60-95 mg/dl of blood urea nitrogen (BUN), in subtotal (3/4) nephrectomized rats. Levels of s-Cr and s-IS in the AST-120-treated rats were significantly lower than those in the untreated control rats. The AST-120-treated rats showed an increase of creatinine clearance. Urinary protein and indoxyl sulfate excretion in the AST-120-treated rats were also significantly lower than those in the untreated control rats. The ratio of glomerular tuft area to the area of Bowman's capsules (GT/BC) in the AST-120-treated rats was significantly lower than that in the untreated control rats. The degree of glomerular sclerosis and tubulointerstitial fibrosis in the AST-120-treated rats was significantly lower than that in the untreated control rats. Furthermore, there was a significant relationship among the degree of GT/BC, glomerular sclerosis, tubulointerstitial fibrosis and the levels of urinary protein excretion. It appears that AST-120 might decrease the accumulation of s-Cr and s-IS, and prevent glomerular sclerosis in early stage renal failure in the subtotal nephrectomized rats.     

The effects of oral adsorbent (AST-120) in the experimental model of chronic renal failure--pathophysiological study on renal function, glomerular hypertrophy, mesangial function and glomerular histology

Oral adsorbent (AST-120) reduces blood levels of urea and creatinine in experimental studies. It has also been shown to retard the progression of chronic renal failure in clinical studies. In the present study, the effect of AST-120 was examined in the rat model of subtotal nephrectomy (sNPX). This experimental model of chronic renal failure is characterized by glomerular hyperfunction, glomerular hypertrophy, increased mesangial trapment of macromolecules and subsequent glomerular sclerosis. We report the effect of AST-120 on glomerular hyperfunction, glomerular hypertrophy and mesangial trapment of macromolecules in the early stage and glomerular function and histology in the late stage of the rat model of sNPX. From 2 days after sNPX, rats were fed regular rat chow with (AST group: AST) or without (control) AST-120. At 2 weeks, iron dextran (ID) was injected intravenously. Three days after the injection, mesangial trapment of ID was largely ameliorated in AST when compared with control (p less than 0.02). The value of mean planar area of glomerulus (PAmean) in AST was significantly lower than that in control (p less than 0.05). At 2 and 9 weeks, the values of GFR and RPF in AST were all statistically higher than those in control. At 9 weeks, whereas average glomerular sclerosis index (SI: 0-4 scale) was 1.07 in control, significantly lower SI (0.57) was noted in AST (p less than 0.05). Thus, AST-120 has effects on glomerular hypertrophy, increased mesangial trapment of macromoleculus and finally the progression of chronic renal failure in the rat model of sNPX. The effects are not through reducing glomerular hyperfunction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of oral adsorbent (AST-120) on renal function,acquired renal cysts and aortic calcification in rats with adriamycin nephropathy

AIMS: The effect of oral adsorbent, AST-120, on the experimental renal disease induced by adriamycin, uninephrectomy and high protein diet proposed as a model of acquired cystic disease of the kidney was investigated. METHODS: 3 mg of adriamycin was injected into the tail vein of rats and 4 weeks later right-side nephrectomy was performed, 2 weeks thereafter 26 rats with urinary protein excretion between 100 and 358 mg/day were selected from 60 rats. Two groups, 13 rats in each group, namely the AST-120-treated group and control group, both of which had equal renal damage before the administration of AST-120 or placebo. AST-120 (0.4 g/100 g BW/day) was administered for 19 weeks. RESULTS: Serum creatinine and BUN in the AST-120-treated group were significantly lower (serum creatinine: 3.3 +/- 2.1 vs. 7.1 +/- 2.7 mg/dl, p < 0.003) and creatinine clearance was higher (0.62 +/- 0.49 vs. 0.29 +/- 0.30 ml/min, p < 0.05) at the final examination than in the control group. Survival rate which was examined using another set of 9 rats was higher in AST-120-treated rats than in AST-120-untreated rats. Serum indoxyl sulfate was significantly lower at all times after using AST-120 in the AST-120-treated group than in contrast to the control group. Histological examination revealed less severe interstitial and cystic changes in the AST-120-treated group. This suggests that AST-120 can prevent or retard the development of acquired renal cystic disease in this model. Aortic calcification tended to be less severe in the AST-120-treated group because of less serum Ca x P products. CONCLUSION: The AST-120-treated group significantly decreased serum creatinine and increased creatinine clearance with less severe renal cystic changes in this model during the later weeks of administration of AST-120 or at death, accompanied with the tendency of less severe aortic calcification.     

Combination therapy with angiotensin-converting enzyme inhibitor and oral adsorbent of uremic toxins can delay the appearance of glomerular sclerosis and interstitial fibrosis in established renal failure

BACKGROUND/AIM: Angiotensin II plays a central role in the progression of chronic renal failure (CRF), and administration of angiotensin-converting enzyme inhibitor (ACEI) in rats delays the progression of CRF. However, ACEI has little effect on CRF progression in rats with established CRF. We therefore examined whether combination therapy with ACEI and oral adsorbent for uremic toxins in the gastrointestinal tract has the desired effect. METHODS: Rats subjected to subtotal nephrectomy were given enalapril at 20 mg/kg (n = 10, group E), AST-120 at 5 g (n = 10, group A), enalapril and AST-120 together at the same doses (n = 10, group EA), or no treatment (n = 10, group C) 8 weeks after the operation. The substances were administered in 100 g rat chow. All animals were pair-fed, and all were killed after 8 weeks of pair-feeding. RESULTS: Body weight did not differ between groups during the study. Blood pressure at week 8 was significantly lower in groups E and EA than in groups C and A (p < 0.05). Urinary protein excretion level and renal plasma flow rate at week 8 were significantly less in groups E and EA than in group C (p < 0.05, p < 0.01). The glomerular filtration rate at week 8 was significantly higher in group EA than in group C (p < 0.05). The glomerular sclerosis index and interstitial fibrosis area at week 8 were significantly less in group EA than in group C (p < 0.01). CONCLUSION: ACEI and AST-120 in combination can delay progression of established CRF in rats by inhibiting the appearance of glomerular sclerosis and interstitial fibrosis.     

An oral sorbent reduces overload of indoxyl sulphate and gene expression of TGF-beta1 in uraemic rat kidneys.

BACKGROUND: An oral adsorbent (AST-120) delays the progression of chronic renal failure (CRF). The aims of the present study are to determine the effects of AST-120 on the localization of indoxyl sulphate in uraemic rat kidneys, and to examine whether AST-120 reduces the renal cortical gene expression of transforming growth factor (TGF)-beta1, tissue inhibitor of metalloproteinase (TIMP)-1 and pro-alpha1(I)collagen, and ameliorates glomerular and tubulointerstitial injuries in uraemic rats. METHODS: Two weeks after 5/6-nephrectomy, 10 rats were divided into pairs such that both rats in each pair exhibited almost the same levels of serum creatinine, blood urea nitrogen and creatinine clearance. One rat from each pair was assigned to a control uraemic group, the other to a uraemic group which received AST-120 everyday for 11 weeks. The localization of indoxyl sulphate was studied by immunohistochemistry using a monoclonal anti-indoxyl sulphate antibody we had developed. The renal cortical gene expression was studied by using northern blotting. RESULTS: Rats treated with AST-120 showed decreased levels of serum creatinine, blood urea nitrogen and urinary protein as well as increased levels of creatinine clearance as compared with control uraemic rats. AST-120 markedly decreased indoxyl sulphate levels in both serum and urine. Immunohistochemistry demonstrated that indoxyl sulphate was localized in the renal proximal tubular epithelial cells, especially of dilated tubules, and that AST-120 markedly reduced the tubular staining of indoxyl sulphate. AST-120 attenuated interstitial fibrosis, tubular injury as well as glomerular sclerosis, and reduced the renal gene expression of TGF-beta1, TIMP-1 and pro-alpha1(I)collagen. CONCLUSIONS: AST-120 reduces the gene expression of TGF-beta1, TIMP-1 and pro-alpha1(I)collagen in the kidneys, and delays the progression of CRF, at least in part, by alleviating the overload of indoxyl sulphate on remnant proximal tubular epithelial cells.     

Effect of an oral adsorbent (AST-120) in rats with daunomycin-induced chronic renal failure

The effect of an oral adsorbent (AST-120) was examined in rats with daunomycin-induced chronic renal failure. Sixteen pairs of daunomycin rats which had similar levels of proteinuria at 4 weeks after being injected with daunomycin were selected. One rat of each pair served as a control and was fed on a standard diet, while the other rats were fed on a diet containing AST-120. The blood creatinine and blood urea nitrogen (BUN) were significantly lower in the rats fed with AST-120 than in the controls. Moreover, the life span of the rats fed with AST-120 was significantly prolonged as compared to that of the control rats. These findings suggest that oral administration of AST-120 may help to prevent rapid deterioration of renal function in experimental chronic renal failure induced by daunomycin in rats.     

Effect of oral adsorbent (AST-120) in the rat model of chronic renal failure induced by adriamycin]

The effect of AST-120 was examined in the rat model of CRF induced by adriamycin (ADM), which is known to induce focal glomerular sclerosis (GS). ADM (2mg/kg) was injected intravenously twice at a 3-wk interval. After 14 wks, rats were paired with control (C) and AST-120 (A) groups according to levels of BUN and proteinuria. Then, the rats were fed regular rat chow with (A, n = 10) or without (C, n = 10) AST-120. After 28 wks, there were more GS in C. Averaged sclerosis index (SI, 0-4 scale) in C was 1.97 (0.94-3.22), while 1.61 (0.60-2.97) in A. When GS was advanced in C (SI > 2.0), largely ameliorated SI was noted in A (2.61 vs. 1.97, C vs. A, p < 0.05 by paired W-test, n = 5 each). Also, in these rats, BUN, serum creatinine and Ht were all improved in A (p < 0.05). Thus, AST-120 was effective in CRF rats induced by ADM when uremia was advanced. The data also indicates that a reduction of uremic toxins could improve glomerular histology and renal function in CRF.     

An oral adsorbent, AST-120, suppresses oxidative stress in uremic rats

BACKGROUND: The production of reactive oxygen species (ROS) has been suggested to play an important role in the progression of chronic kidney disease (CKD). An oral adsorbent, AST-120, removes uremic toxins such as indoxyl sulfate (IS) and delays the progression of CKD, but the effect on ROS production is unknown. The present study aimed to determine whether AST-120 reduces oxidative stress in uremic rat kidneys using markers of ROS production such as acrolein and 8-hydroxy-2'-deoxyguanosine (8-OHdG). METHODS: Daily administration of AST-120 was started 6 weeks after 5/6 nephrectomy and continued for 18 weeks. The changes in metabolic data, serum and urine IS levels, urinary excretion of markers of oxidative stress, and renal histological findings were investigated in uremic rats with or without AST-120 treatment. RESULTS: In parallel with the increase in serum and urine IS, the serum creatinine, urinary protein and acrolein levels started to increase at 6 weeks, but urinary 8-OHdG remained unchanged and significantly increased at 18 weeks in uremic rats. AST-120 markedly and significantly attenuated increases in uremic toxins and oxidative stress levels as well as the histological changes in glomerular sclerosis, interstitial fibrosis, and the tubular staining of 8-OHdG. CONCLUSION: AST-120 suppressed the progression of CKD, at least in part, via attenuation of oxidative stress induced by uremic toxin.     

Effects of oral carbonic adsorbent (AST-120) on kidney of early-stage chronic kidney disease rats

Abstract

Aim: to investigate the therapeutic effects of oral carbonic adsorbent on rats with early-stage renal failure. Methods: The early-stage renal failure model was established with three-fourth subtotal nephrectomy Wistar rats. Four weeks after the subtotal nephrectomy, the rats were randomly divided into four groups: (1) adsorbent diet (AD) rats; (2) low protein diet (LPD) group; (3) low protein and AD rats; and (4) normal diet rats as control (ctrl) group. Sham operation group is set as well. The therapeutic effects of adsorbent were examined after 15 weeks treatment. Results: The level of 24 hours urinary protein excretion, serum creatinine (Scr), index of glomerulosclerosis (GSI) and tubulointerstitial fibrosis score (TIFS) of rats with adsorbent or LPD treatment are significantly lower than ctrl group rats. The combination of adsorbent and LPD lowered level of 24 hours urinary protein excretion, Scr, index of GSI and TIFS compared with LPD or adsorbent treatment alone. Conclusion: Both AST-120 and LPD treatment lowered the Scr and blood urea nitrogen level as well as ameliorated the proteinuria and glomerular and tubulointerstitial damage of rats with early stage renal failure. The combined treatment of oral carbonic adsorbent and LPD showed greater therapeutic effects.     

Oral adsorbent AST-120 ameliorates interstitial fibrosis and transforming growth factor-beta(1) expression in spontaneously diabetic (OLETF) rats

Diabetic nephropathy is a common cause of end-stage renal disease. The administration of an oral adsorbent, AST-120, prevents the progression of chronic renal failure in uremic rats and undialyzed uremic patients. This study was designed to determine if AST-120 slows the progression of diabetic nephropathy using Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of non-insulin-dependent diabetic mellitus. At 21 weeks of age the OLETF rats were divided into 2 groups: AST-120-administered OLETF rats (n = 7), and control OLETF rats (n = 7). LETO rats, which are genetically similar to the OLETF rats but not diabetic, were also included. After the oral administration of AST-120 for 65 weeks, renal function and pathological changes were investigated in the 3 groups. The administration of AST-120 to the OLETF rats attenuated the progression of glomerular sclerosis, interstitial fibrosis, tubular injury as well as renal dysfunction, and reduced the serum and urinary levels of indoxyl sulfate. Furthermore, AST-120 administration reduced the interstitial expression of transforming growth factor (TGF)-beta(1) and tissue inhibitor of metalloproteinase (TIMP)-1, as well as interstitial infiltration of macrophages. The TGF-beta(1)-stained interstitial area showed positive correlations with the interstitial fibrosis area, the number of TIMP-1-positive cells, and the number of macrophages, and showed a negative correlation with creatinine clearance. In conclusion, AST-120 reduced the interstitial expression of TGF-beta(1) and TIMP-1, and the interstitial infiltration of macrophages, and ameliorates the progression of diabetic nephropathy in OLETF rats.     

Correction by oral adsorbent of abnormal digestive tract milieu in rats with chronic renal failure

In order to examine the mechanism by which the oral carbonaceousadsorbent, AST-120 delays the appearance of glomerular sclerosis,experiments were carried out in 120 male Sprague-Dawley ratsweighing 285–320 g. The rats were first subjected to 2/3,3/4, and 4/5 nephrectomy (n=40). The experiments were begunat 2 weeks after the surgery, and were performed over an 8-weekperiod. Half of each group (n=20) was administered 1 g/day ofliquid AST-120, and the other half received liquid vehicle solutionwith pair feeding in each group. In the 2/3 nephrectomized groupthe administration of AST-120 delayed the occurrence of glomerularhypertrophy and prevented the appearance of glomerular sclerosiswithout any significant differences in renal function, systemicblood pressure (SBP), and urinary protein excretion (U-P). Inthe 3/4 nephrectomized group the administration of AST-120 delayedthe appearance of glomerular hypertrophy and sclerosis withsignificant decreases in SBP and U-P. In the 4/5 nephrectomizedgroup the administration of AST-120 delayed the appearance ofglomerular sclerosis and prevented a decrease in renal function.It is concluded that administration of the oral adsorbent AST-120delays the occurrence of glomerular sclerosis by delaying theappearance of glomerular hypertrophy, systemic hypertension,and the increase in proteinuria. It can be therefore mentionedthat the accumulating substances in the digestive tract worsenthe abnormal milieu of chronic renal failure.     

Early morphological changes of tubules in rats with chronic renal failure.

We investigated the early changes of tubules and effect of the oral adsorbent, AST-120, on the early changes of tubules in rats with chronic renal failure. Sprague-Dawley rats were divided into two groups with and without AST-120, after 3/4 nephrectomy. Although there were no significant differences in levels of blood urea nitrogen, serum creatinine, creatinine clearance, inulin clearance, para-aminohippuric acid clearance and urinary N-acetyl-beta-D-glucosaminidase at week 8 between the two groups, the amount of 24-hour urinary protein excretion and the direct systolic blood pressure at week 8 were significantly decreased in the group with AST-120. Examinations by light microscopy at week 8 revealed that proteinaceous casts in the tubules, tubular dilatation and infiltration of monocytes into the interstitium in the group with AST-120 were less prominent than those in the group without AST-120. A significant difference in numbers of proteinaceous casts was noted at week 8 between the two groups. In rats with chronic renal failure at the early stage, it is concluded that the formation of proteinaceous casts, resulting in tubular damage, is increased and that AST-120 delays the occurrence of proteinaceous casts by delaying the increase in urinary protein excretion.     

Oral sorbent AST-120 increases renal NO synthesis in uremic rats.

OBJECTIVE: The urine level of nitric oxide (NO) metabolites, i.e., nitrates/nitrites (NOx), in chronic renal failure (CRF) is decreased because of reduced renal synthesis of NO. We determined whether the administration of an oral sorbent, AST-120, increases the urine level of NOx and the renal expression of nitric oxide synthase (NOS) isoforms in CRF rats. METHODS: Chronic renal failure rats were produced by 4/5 nephrectomy. Rats were randomized into two groups: CRF control rats, and AST-120-treated CRF rats. The AST-120 was administered to the rats at a dose of 4 g/kg with powder chow for 16 weeks, whereas powder chow alone was administered to control rats. The urine levels of NOx were measured by using a NOx colorimetric assay kit. The expression of endothelial NOS (eNOS), inducible NOS (iNOS), and neuronal NOS (nNOS) in the kidney was determined by immunohistochemistry. Serum and urine levels of indoxyl sulfate were determined by high-performance liquid chromatography. RESULTS: Urine levels of NOx and the expression of glomerular eNOS and tubulointerstitial nNOS were significantly decreased in CRF rats compared with normal rats. The administration of AST-120 to CRF rats significantly increased urine levels of NOx and the expression of glomerular eNOS and tubulointerstitial nNOS. The administration of AST-120 to CRF rats significantly decreased urine and serum levels of indoxyl sulfate. CONCLUSIONS: The oral sorbent AST-120 increases NO synthesis in the kidneys of uremic rats by increasing the renal expression of eNOS and nNOS, through alleviation of indoxyl sulfate overload on the kidney.     

Relationship between insulin resistance and uremic toxins in the gastrointestinal tract

The relationship between insulin resistance and local uremic toxins was examined using an oral adsorbent. Fourteen rats demonstrating a diabetic state underwent two-thirds, nephrectomy and were divided into two groups. The control group was fed standard rat chow, and the test group was fed standard rat chow containing 5% AST-120. The target level of blood glucose was achieved by controlling the dosage of exogenous insulin. All rats were sacrificed at week 6. Body weight, blood glucose level, and renal function at week 6 were not significantly different between both groups. However, the mean blood glucose level and the mean dose of exogenous insulin in the AST-120-fed group were significantly reduced as compared with the control group. The results of the present study indicate that administration of an oral adsorbent in diabetic nephropathy decreases the doses of exogenous insulin and improves insulin resistance, and that uremic toxins which exist in the gastrointestinal tract play important roles.     

Effect of badoushuang on progressive glomerular sclerosis in rats with 7/8 nephrectomy]

Effect of Badoushuang (Semen crotonis pulveratum) was studied in the 7/8 nephrectomied rats, which we could establish as progressive glomerulosclerosis model in rats (Jap J Nephrol 32: 127, 1990). Badoushuang was administered into rats orally 60 mg/kg/day every day after 7/8 nephrectomy. As controls 7/8 nephrectomied rats were used. No adverse effect of Badoushuang were noted during 8 weeks of observation periods. Administration of Badoushuang, in rats with a remnant kidney, decreases urinary protein and lowers blood pressure, keeps creatinine clearance and lowers serum creatinine level and BUN. Morphologically glomerular hypertrophy, crescent formation and sclerosis were less in experimental treated rats. These results suggest Badoushuang ameliorates the progressive kidney disease of rats with subtotal renal ablation. Further study is necessary to clarify the effect of Basoushuang on progressive glomerular sclerosis.     

Indoxyl sulfate-lowering capacity of oral sorbents affects the prognosis of kidney function and oxidative stress in chronic kidney disease.

OBJECTIVES: Indoxyl sulfate shows nephrotoxicity and is a stimulating factor for progression of chronic kidney disease (CKD). This study was conducted to determine (1) whether the indoxyl sulfate-lowering capacity of oral sorbents (Kremezin [AST-120], Kureha Corporation, Tokyo, Japan; Merckmezin, Merck Hoei Ltd., Osaka, Japan) affects the prognosis of kidney function in CKD, and (2) whether oral sorbents reduce the markers of oxidative stress. METHODS: Rats with CKD were produced by 4/5 nephrectomy and were randomized into 3 groups: control rats, Merckmezin-treated rats, and Kremezin-treated rats. Kremezin and Merckmezin were administered to rats at a dose of 4 g/kg with powder chow for 16 weeks, whereas powder chow alone was administered to control rats. RESULTS: Administration of Kremezin significantly decreased serum and urine levels of indoxyl sulfate and serum creatinine and significantly increased creatinine clearance as compared with control values. The change in serum indoxyl sulfate noted from the initial to the final week showed a positive correlation with the change in serum creatinine and a negative correlation with the change in creatinine clearance. Kremezin significantly reduced urine levels of acrolein, a marker of oxidative stress, as compared with control levels. CONCLUSIONS: The indoxyl sulfate-lowering capacity of oral adsorbents affects the prognosis of kidney function in CKD. The more serum indoxyl sulfate is reduced, the better kidney function is preserved. Kremezin alleviates oxidative stress in the kidneys by reducing serum levels of indoxyl sulfate.     

Uremic toxins adsorbed by AST-120 promote tubular hypertrophy and interstitial fibrosis in nephrectomized rats

BACKGROUND: Uremic toxins have been shown to promote glomerular hypertrophy. The present study was performed to elucidate the relation between uremic toxins and tubulointerstitial changes. METHODS: Sixty male Sprague-Dawley rats underwent 2/3 nephrectomy (Nx; n = 30) and 4/5 Nx (n = 30). Experiments were initiated 2 weeks after surgery, and were performed over an 8-week period. Half of each group (Nx-A) was administered 1 g/day of an oral carbonaceous adsorbent, AST-120, with pair-feeding, and the other half (Nx-C) served as controls. All rats were sacrificed at week 8 after a clearance study. RESULTS: The shortest diameter of proximal tubules (PTD) and interstitial fibrosis area (IFA) at week 8 in 2/3 Nx-A rats was significantly decreased compared to that in 2/3 Nx-C rats (similar body weights, systolic blood pressures, glomerular filtration rates, and urinary protein excretion levels). The values of PTD and IFA, glomerular filtration rate and urinary protein excretion level at week 8 in 4/5 Nx-A rats were significantly decreased compared to those in 4/5 Nx-C rats (similar body weights and systolic blood pressures). CONCLUSION: Administration of AST-120 minimized the appearance of proximal tubular hypertrophy and interstitial fibrosis, and subsequently prevented the occurrence of proteinuria and decreased renal function. The present study indicates that uremic toxins adsorbed by AST-120 promote tubular hypertrophy and interstitial fibrosis in nephrectomized rats.     

The oral adsorbent AST-120 attenuates the progression of hyperlipidemia and glomerulosclerosis in spontaneous hypercholesterolemic rats (SHCRs)

Background. The oral adsorbent, AST-120 Kureha Chemical, has been shown to attenuate the progression of chronic renal failure in rats and humans. Spontaneous hypercholesterolemic male rats, (SHC rats; SHCRs) have been introduced for experimentation because they develop progressive hyperlipidemia and glomerulosclerosis on a cholesterol-free standard diet by their 30th week of life. Methods. The effects of AST-120 were studied in SHCRs. Twenty 10-week-old SHCRs were divided into two groups: a control group (n = 10), and an AST-120 group (n = 10). The experiment was begun at the 12th week and completed at the 34th week of life. Results. At the end of the experiment, we found that the serum levels of total cholesterol were 40% lower in the AST-120 rats than in the control rats (P < 0.01). The creatinine clearance in the AST group was 40% higher than that in the controls (P < 0.05). At the age of 20 weeks, postheparin lipoprotein lipase in the AST-120 SHCRs and in Sprague-Dawley rats with normal serum lipid levels was comparable, but was clearly lower in the control SHCRs. Finally, in a pathological investigation that determined a sclerosis index for all kidneys, this was significantly lower in the AST group than in the control animals (P < 0.01). Conclusions. The reduction of serum lipid levels following the administration of the AST-120 oral adsorbent is associated with amelioration of renal functional and structural changes in SHCRs. Received: January 8, 1999 / Accepted: June 15, 1999     

Protein restriction and AST-120 improve lipoprotein lipase and VLDL receptor in focal glomerulosclerosis

BACKGROUND: Imai rats exhibit spontaneous focal glomerulosclerosis (FGS) with progressive proteinuria and hyperlipidemia leading to renal insufficiency by age 34 weeks. Recently, we reported marked down-regulations of skeletal muscle and adipose tissue lipoprotein lipase (LPL) and very low-density lipoprotein (VLDL) receptor in male Imai rats at 32 weeks of age. Dietary protein restriction and oral adsorbent AST-120 (AST) have been shown to slow progression of renal disease and attenuate hyperlipidemia in the Imai rats. This study tested the hypothesis that amelioration of proteinuria by protein restriction or use of oral adsorbent AST-120 beginning at 10 weeks of age may improve renal disease and LPL and VLDL receptor deficiencies in Imai rats. METHODS: Ten-week-old male Imai rats were randomly assigned to those fed either a regular diet, low protein diet (LPD), or regular diet containing the adsorbent preparation, AST-120. Ten-week-old male Sprague-Dawley rats served as controls. The animals were observed for 24 weeks. Six rats were included in each group. All diets were prepared in powder form. RESULTS: The untreated 34-week-old Imai rats showed severe proteinuria, hypoalbuminemia, 50% reduction in creatinine clearance, hypercholesterolemia, hypertriglyceridemia, and elevated plasma VLDL concentration. This was associated with significant reductions in plasma post-heparin LPL activity, hepatic lipase activity, as well as adipose tissue and skeletal muscle immunodetectable LPL and VLDL receptor proteins. Protein restriction mitigated the decline in creatinine clearance, ameliorated proteinuria, hypoalbuminemia, hypertension, and hypercholesterolemia, lowered plasma VLDL, and improved plasma postheparin LPL activity, hepatic lipase activity, LPL, and VLDL receptor proteins in skeletal muscle and adipose tissue. Similar improvements were observed in all parameters with AST administration. CONCLUSION: Moderate protein restriction and use of oral adsorbent can slow progression of renal disease and, thereby, ameliorate LPL, hepatic lipase, and VLDL receptor deficiencies and the associated hyperlipidemia in rats with spontaneous FGS.