Responsiveness of sphingosine phosphate lyase insufficiency syndrome to vitamin B6 cofactor supplementation

Sphingosine-1-phosphate (S1P) lyase is a vitamin B6-dependent enzyme that degrades sphingosine-1-phosphate in the final step of sphingolipid metabolism. In 2017, a new inherited disorder was described caused by mutations in SGPL1, which encodes sphingosine phosphate lyase (SPL). This condition is referred to as SPL insufficiency syndrome (SPLIS) or alternatively as nephrotic syndrome type 14 (NPHS14). Patients with SPLIS exhibit lymphopenia, nephrosis, adrenal insufficiency, and/or neurological defects. No targeted therapy for SPLIS has been reported. Vitamin B6 supplementation has therapeutic activity in some genetic diseases involving B6-dependent enzymes, a finding ascribed largely to the vitamin's chaperone function. We investigated whether B6 supplementation might have activity in SPLIS patients. We retrospectively monitored responses of disease biomarkers in patients supplemented with B6 and measured SPL activity and sphingolipids in B6-treated patient-derived fibroblasts. In two patients, disease biomarkers responded to B6 supplementation. S1P abundance and activity levels increased and sphingolipids decreased in response to B6. One responsive patient is homozygous for an SPL R222Q variant present in almost 30% of SPLIS patients. Molecular modeling suggests the variant distorts the dimer interface which could be overcome by cofactor supplementation. We demonstrate the first potential targeted therapy for SPLIS and suggest that 30% of SPLIS patients might respond to cofactor supplementation.

Lysosomal protease cathepsin D; a new driver of apoptosis during acute kidney injury

Acute kidney injury (AKI) is an abrupt reduction in kidney function caused by different pathological processes. It is associated with a significant morbidity and mortality in the acute phase and an increased risk of developing End Stage Renal Disease. Despite the progress in the management of the disease, mortality rates in the last five decades remain unchanged at around 50%. Therefore there is an urgent need to find new therapeutic strategies to treat AKI. Lysosomal proteases, particularly Cathepsin D (CtsD), play multiple roles in apoptosis however, their role in AKI is still unknown. Here we describe a novel role for CtsD in AKI. CtsD expression was upregulated in damaged tubular cells in nephrotoxic and ischemia reperfusion (IRI) induced AKI. CtsD inhibition using Pepstatin A led to an improvement in kidney function, a reduction in apoptosis and a decrease in tubular cell damage in kidneys with nephrotoxic or IRI induced AKI. Pepstatin A treatment slowed interstitial fibrosis progression following IRI induced AKI. Renal transplant biopsies with acute tubular necrosis demonstrated high levels of CtsD in damaged tubular cells. These results support a role for CtsD in apoptosis during AKI opening new avenues for the treatment of AKI by targeting lysosomal proteases.

[Protective Effects of Different Extracts of Imperatae Rhizoma in Rats with Adriamycin Nephrosis and Influence on Expression of TGF-β1, and NF-κB p65]

OBJECTIVE

To study the protective effect of Imperatae Rhizoma extract on renal tissues in rats with Adriamycin nephrosis, and to explore the possible mechanism.

METHODS

The nephrosis model was induced by adriamycin 6.5 mg/kg intravenously in rats. The rats were randomly divided into seven groups, including normal group, model group, predisone group, petroleum ether groups, ethyl acetate group ,alcohol group, and water parts group, and treated for eight weeks. The protein content of 24 hours urine excretion was tested respectively by automatic biochemistry analyzer each week. After eight weeks, BUN, CRE, TCHO, TG, TP and ALB in serum were examined by automatic biochemistry analyzer. The TNF-α in serum was measured by ELISA. The expression of TGF-β1, and NF-κB p65 in renal tissues were detected by immunohistochemistry respectively. The pathological changes in the renal were observed by light microscope.

RESULTS

Compared with the model group ,the proteinuria of the rats in ethyl acetate group obviously reduced at the 6th, 7th, 8th week, the content of TNF-α in serum and the expression of TGF-β1, and NF-κB p65 in renal tissues significantly reduced, but the content of TP and ALB in serum were increased obviously. In the alcohol and water parts groups ,the level of TG in serum and the protein content of 24 hours urine excretion of the 6th and 7th week were significantly decreased. The ethyl acetate, alcohol and water parts groups ameliorated the changes of pathology in renal.

CONCLUSION

The different extracts of Imperatae Rhizoma had different protective effect in rats with adriamycin nephrosis, and the effect of ethyl acetate group was more stronger than that of other groups. The mechanism may be related to reducing the expression of NF-κB p65 and TGF-β1, and the content of TNF-α inrenal tissues of rats.

The effect of candesartan on the pharmacokinetics of enalaprilat in nephrotic rats

BACKGROUND AND OBJECTIVES

The adverse reactions in combination of angiotensin-converting enzyme inhibitors (ACEIs) and Ang II receptor blockers (ARBs) were severer than that in monotherapy for patients with nephropathy. The effect of candesartan on pharmacokinetics of enalaprilat in nephrotic rats was investigated to make references for the clinical therapy in patients with nephropathy to avoid related adverse effects.

MATERIALS AND METHODS

Nephrotic rats were prepared by adriamycin injection. Control group and one nephrotic group received enalapril alone, another nephrotic group received enalapril and candesartan simultaneously. Blood samples were drawn at time points after a single oral administration. The concentration of enalaprilat was determined using LC-MS/MS.

RESULTS

Compared with control group and nephrotic group received enalapril alone respectively, Tmax of enalaprilat in nephrotic group received both enalapril and candesartan cilexetil prolonged about 21.43% and 6.224%, respectively; AUC(0-t) increased by 185.3% and 60.63%, respectively; Cmax increased by 219.4% and 56.64%, respectively; t1/2 increased by 163.7% and 30.05%, respectively; CL/F reduced by 65.12% and 40.78%, respectively. There were no significant differences of the V1/F of enalaprilat between three groups. The CL/F and t1/2 of enalaprilat showed significant correlations with serum creatinine (Scr) respectively (r = -0.7502; r = 0.5626).

DISCUSSION

The combination with candesartan in nephrotic rats significantly changed the pharmacokinetics of enalaprilat, showing increased accumulation and decreased elimination. In view of these findings, we should lower dosage and prolong dosing interval for nephrotic patients in the combination of enalapril and candesartan.

Effects of 22-oxa-calcitriol on podocyte injury in adriamycin-induced nephrosis

BACKGROUND

In various animal studies, vitamin D has been shown to have a significant effect on reduction of proteinuria and the progression of kidney disease. However, little is known on its renoprotective effect in adriamycin (ADR)-induced nephrosis mice. The present study was intended to determine the therapeutic benefit of 22-oxa-calcitriol (OCT), a vitamin D analog, in reducing proteinuria and its renoprotective effect, i.e. preventing podocyte injury on ADR-induced nephrosis mice.

METHODS

Three experimental groups were used as follows: (1) nephrosis mice, established by a single intravenous injection of ADR; (2) ADR+OCT mice, nephrosis mice treated with OCT, and (3) mice treated only with OCT as the control group. Podocyte injury was assessed by podocyte apoptosis using the TUNEL assay, podocyte counting, podocyte-specific expressed protein by immunofluorescence and Western blot analysis, and foot process effacement using electron microscopy.

RESULTS

Lower proteinuria was observed in ADR+OCT mice. Improvement in glomerulosclerosis and interstitial fibrosis, and prevention of glomerular hyperfiltration were observed in ADR+OCT mice. Immunofluorescence and Western blot analyses showed restoration of downregulated expression of nephrin, CD2AP and podocin. Nevertheless, dendrin expression was not restored. An insignificant reduction in podocyte numbers was found in ADR+OCT mice. Complete foot process effacement was partially prevented in ADR+OCT mice.

CONCLUSIONS

The results indicate that OCT reduces podocyte injury and has renoprotective effects in ADR nephrosis mice.

Protective effects of Huang Qi Huai granules on adriamycin nephrosis in rats

Huang Qi Huai (HQH) granules, a mixture of Chinese herbs, contains trametes robiniophila murr, wolfberry fruit, and Polygonatum. We investigated the mechanism of the protective effects of HQH on adriamycin nephrosis (ADR) in rats. Adriamycin nephrotic rats were induced by a single dose of 5 mg/kg adriamycin. For the HQH-treated adriamycin nephrosis group, 1 day after treatment with 5 mg/kg adriamycin, the rats were administered once-daily oral gavage of 2 mg/kg HQH for 15 days. All the rats were killed at day 15. Histological changes were observed by light microscopy and transmission electron microscope. Nephrin and podocin expression levels were measured by real-time RT-PCR and Western blot. Proteinuria was measured by the Bradford protein assay. Serum TNF-α and IL-1β levels were evaluated by ELISA. Macrophage infiltration was detected by immunohistochemistry and immunoblotting, respectively. ADR rats showed heavy proteinuria, podocyte and tubulointerstitial injury, macrophage infiltration, and increased levels of serum cytokines TNF-α and IL-1β. HQH significantly ameliorated the adriamycin-induced renal injury. These data were validated in the cultured podocytes. The podocytes were treated by adriamycin in the presence or absence of HQH and nephrin and podocin expression and TNF-α and IL-1β synthesis and secretion were determined by real-time RT-PCR, immunoblotting, and ELISA, respectively. Adriamycin significantly reduced nephrin and podocin expression, which was significantly restored by the treatment of HQH. HQH treatment inhibited adriamycin-induced TNF-α and IL-1β expression. Our findings suggest that HQH significantly reduces proteinuria, prevents podocyte injury, and ameliorates tubulointerstitial damage. Inhibition of inflammatory cytokine expression and macrophage infiltration may be the protective mechanism of HQH.

[Effects of Qufengtongluo recipe on proteinuria and glomerular filtration membrane in rats with adriamycin-induced nephropathy]

OBJECTIVE

To assess the therapeutic effect of Qufengtongluo (QFTL) recipe against proteinuria and glomerular filtration membrane damage in rats with adriamycin-induced nephropathy (AN).

METHODS

Fifty-six SD rats were randomized into normal control (A) and AN model groups. In the AN model group, the rat AN models established by a single intravenous injection of adriamycin via the tail vein were subdivided into model (B), QFTL recipe (C), prednisone (D), and benazepril (E) groups 3 weeks after adriamycin injection. The 24-h urinary protein level was measured and the expression of anionic sites on the filtration membrane was evaluated using electron microscope with PEI staining. Nephrin expression on the glomerular filtration membrane was detected with indirect immunofluorescence assay.

RESULTS

Compared with group A, the model group showed significantly increased level of 24-h urinary protein (P<0.01), suggesting successful establishment of the AN model. Treatment with QFTL recipe obviously lowered the 24-h urinary protein (P<0.01), and increased the expression of anionic sites and nephrin on the glomerular filtration membrane in the AN rats (P<0.01).

CONCLUSION

QFTL recipe can effectively decrease 24-h urinary protein, improve the symptoms, and up-regulate the expressions of anionic sites and nephrin on the glomerular filtration membrane in rats with AN.

Effects of celecoxib and nordihydroguaiaretic acid on puromycin aminonucleoside-induced nephrosis in the rat

The selective cyclooxygenase-2 (COX-2) and 5-lipoxygenase (LOX) inhibitors might inhibit prostaglandin synthesis and reduce proteinuria. The present study was designed to investigate the anti-proteinuric effects of nordihydroguaiaretic acid (NDGA) as compared with celecoxib in puromycin aminonucleoside (PAN) nephrosis rats. Fifty five male Sprague-Dawley rats were divided into 4 groups; A, normal control; B, PAN group; C, PAN+COX-2 inhibitor (celecoxib) group; and D, PAN+5-LOX inhibitor (NDGA) group. After induction of PAN nephrosis through repeated injections of PAN (7.5 and 15 mg/100 g body weight), rats were treated with celecoxib, NDGA, or vehicle for 2 weeks. Twenty four hour urine protein excretions were significantly lower in PAN+celecoxib and PAN+NDGA groups than in PAN group. Serum creatinine (SCr) concentrations and 24 hr urine creatinine clearances (CCr) were not significantly different in the four groups. Electron microscopy showed that podocyte morphology was changed after the induction of PAN nephrosis and was recovered after celecoxib or NDGA administration. Celecoxib significantly recovered the expressions of nephrin, CD2AP, COX-2, and TGF-beta. NDGA also recovered TGF-beta expression, but did not alter the expressions of nephrin, CD2AP and COX-2. The present study suggested that celecoxib and NDGA might effectively reduce proteinuria in nephrotic syndrome without impairing renal function.

Beneficial effects of the Rho kinase inhibitor Y27632 in murine puromycin aminonucleoside nephrosis

BACKGROUND AND AIMS

Rho kinase (ROCK) inhibition reduces systemic blood pressure (BP) and decreases renal damage in animal models of kidney disease. The aim of this study was to determine if ROCK inhibition might have beneficial effects in glomerular disease processes that are independent of systemic BP.

METHODS

We investigated the effects of the ROCK inhibitor Y27632 and hydralazine in murine puromycin aminonucleoside (PAN) nephrosis.

RESULTS

Treatment with either Y27632 or hydralazine similarly reduced systolic BP compared to vehicle-treated controls. Seven days after treatment with PAN, albuminuria, proteinuria and effacement of podocyte foot processes were significantly reduced in Y27632- and hydralazine-treated mice compared to vehicle-treated animals. Treatment with PAN significantly reduced expression of the podocyte proteins nephrin and Neph1, and the loss of glomerular nephrin was attenuated by treatment with Y27632 but not by treatment with hydralazine. In cultured podocytes, PAN potently activated both Rho and ROCK, and PAN-induced ROCK activation was prevented by Y27632.

CONCLUSIONS

The ROCK inhibitor Y27632 attenuated glomerular nephrin loss in murine PAN nephrosis independent of its effects on systemic BP.

Effect of combining ACE inhibition with aldosterone blockade on proteinuria and renal damage in experimental nephrosis

Aldosterone has pro-fibrotic properties and is a potential target for additional intervention in patients with chronic renal disease showing resistance to therapy during treatment with angiotensin-converting enzyme inhibitors (ACEi). Combining ACEi and aldosterone receptor blockade (aldoRB) in proteinuric renal disease reduces proteinuria, but effects on proteinuria-induced renal damage are unknown. We studied the effect of ACEi/aldoRB in adriamycin nephrosis (AN). Six weeks after injection of adriamycin in Wistar rats, randomized treatment with vehicle (VEH, n=8), aldoRB (n=12), ACEi (n=10), or a combination of ACEi/aldoRB (n=14) was given for 12 weeks. Healthy rats served as controls (n=6). Renal damage was quantified by markers of tubular injury (osteopontin (OPN) and kidney injury molecule-1 (Kim-1)), pre-fibrotic lesions (alpha-smooth muscle actin (SMA)), interstitial fibrosis (IF), and focal glomerulosclerosis (FGS). In AN animals, proteinuria was increased compared with controls. ACEi and ACEi/aldoRB significantly reduced proteinuria compared with VEH, whereas aldoRB monotherapy was without effect. Blood pressure was reduced in ACEi and ACEi/aldoRB compared with VEH and aldoRB. OPN and Kim-1 were increased in AN animals, but significantly reduced by ACEi/aldoRB. Treatment with ACEi and ACEi/aldoRB prevented an increase of SMA, IF, and FGS. In conclusion, ACEi/aldoRB effectively reduced proteinuria and markers of tubular injury and prevented renal damage in this rat model of chronic proteinuria-induced renal damage.

Beneficial impact of spironolactone on nephrotic range albuminuria in diabetic nephropathy

Reduction of nephrotic range albuminuria is associated with markedly improved renal and cardiovascular outcome in patients with diabetic nephropathy. Aldosterone has been suggested to play a role in the progression of diabetic nephropathy. We therefore aimed to evaluate the short-term effect of aldosterone antagonism with spironolactone on nephrotic range albuminuria and blood pressure in diabetic nephropathy. Twenty Caucasian patients with diabetic nephropathy and nephrotic range albuminuria (>2500 mg/24 h) despite recommended antihypertensive treatment completed this double-masked, randomized crossover trial. Patients were treated in random order with spironolactone 25 mg once daily and matched placebo for 2 months, on top of ongoing antihypertensive treatment, including an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker in maximally recommended doses. Median (range) number of antihypertensive drugs was 3 (2-5). After each treatment period, albuminuria, 24-h ambulatory blood pressure, and glomerular filtration rate (GFR) were determined. Spironolactone on top of recommended renoprotective treatment induced a 32% (95% confidence interval (CI): 21-42%) reduction in albuminuria from (geometric mean (95% CI)) 3718 (2910-4749) mg/24 h on placebo treatment (P<0.001). There was a significant reduction in 24-h blood pressure of 6 (2-10)/4 (2-6) mm Hg and day blood pressure of 7 (3-12)/5 (3-7) mm Hg (P<0.01), whereas night blood pressure remained unchanged. Spironolactone induced an insignificant reversible reduction in GFR of 3 ml/min/1.73 m2 from 64 (27) ml/min/1.73 m2. No patients were excluded due to adverse events. Our results suggest that spironolactone treatment on top of recommended renoprotective treatment including maximal renin-angiotensin system blockade may offer additional renoprotection in patients with diabetic nephropathy and nephrotic range albuminuria.

A free radical scavenger but not FGF-2-mediated angiogenic therapy rescues myonephropathic metabolic syndrome in severe hindlimb ischemia

The therapeutic use of angiogenic factors shows promise in the treatment of critical limb ischemia; however, its potential for myonephropathic metabolic syndrome (MNMS), a fatal complication caused by arterial reconstruction, has not been elucidated. The objective of this study was to evaluate the effectiveness of recombinant Sendai virus-mediated gene transfer of fibroblast growth factor-2 (FGF-2) directly compared with that of a radical scavenger, MCI-186, in a rat model of MNMS. MNMS was surgically induced by aortic occlusion below renal arteries for 4 h, followed by 6 h of reperfusion. Administration of MCI-186 (twice; iv 5 min before induced ischemia and ip 5 min before reperfusion; 10 mg/kg, respectively), but not FGF-2 gene transfer (once, 48 h before induced ischemia), dramatically prevented the increase of serum biochemical markers as well as the edema of the gastrocnemius muscle. The effect of MCI-186 was accompanied by the marked suppression of the neutrophilic infiltration into the local (muscle) and remote (lung) organs. Although serum and muscular levels of a neutrophil-chemoattractant (growth-related oncogene/cytokine-induced neutrophil chemoattractant-1) were not affected by any treatment, the serum level of soluble intercellular adhesion molecule-1 was decreased by treatment with MCI-186 but not by treatment with FGF-2. These results suggest the distinct mechanism of MNMS from critical limb ischemia without reperfusion. Therefore, radical scavenging should be paid more attention than therapeutic angiogenesis when arterial circulation is reconstructed.

Beneficial effects of orosomucoid on the glomerular barrier in puromycin aminonucleoside-induced nephrosis

BACKGROUND

In a hitherto unconfirmed report, orosomucoid was reported to ameliorate the nephrotic syndrome induced by puromycin aminonucleoside (PAN) in rats.

METHODS

We wanted to test this hypothesis and extend the analysis of the effects on the glomerular barrier. Glomerular filtration rate (GFR), and fractional clearance for albumin (theta(albumin)) and for neutral Ficolls were estimated in cooled isolated perfused kidneys. Modern transport equations were used to estimate glomerular size selectivity and charge selectivity. Also, podocyte morphology was studied. Four groups of rats (4 x n = 8) were administered PAN intraperitoneally and treated daily for 5 days with orosomucoid in two different doses (groups A and B), albumin (group C) or saline (group D). Two additional groups of rats (2 x n = 8) were used as controls and these rats received either saline (group E) or orosomucoid (group F) but no PAN.

RESULTS

Treatment with orosomucoid restored podocyte morphology and renal function from the damaging effects of PAN in a dose-dependent manner. GFR was significantly reduced by PAN (groups C and D) when compared with controls (groups E and F). This effect was partly (group A) or completely (group B) reversed by orosomucoid. The theta(albumin) was 0.002+/-0.001 (mean+/-SEM) in controls (group E) and was unaffected by orosomucoid per se (group F). PAN increased theta(albumin) to 0.020+/-0.001 in group C and to 0.021+/-0.001 in group D, while it was significantly less in group A, 0.014+/-0.001, P<0.05. The heterogeneous charged fibre model analysis revealed that PAN reduced the relative volume of negatively charged fibres, phi, from 7.1+/-0.08% (group E) to 48% of this value in groups C and D (P<0.001); phi was 4.5+/-0.04% in group A, 5.3+/-0.44% in group B, and 6.1+/-0.11% in group F.

CONCLUSION

High doses of orosomucoid completely normalized the glomerular barrier in six out of eight animals with puromycin-induced nephrotic syndrome. Thus, orosomucoid has a promising therapeutic potential for certain kidney disorders.

Henoch-Schönlein purpura nephritis with nephrotic-range proteinuria: histological regression possibly associated with cyclosporin A and steroid treatment

OBJECTIVE

To clarify the therapeutic role of cyclosporin A (CyA) for patients with Henoch-Schönlein purpura nephritis (HSPN) showing nephrotic-range proteinuria.

METHODS

The clinical and histological findings of eight children (7.7+/-3.8 years), who were treated with CyA and prednisolone, were evaluated retrospectively. All underwent a renal biopsy before therapy, and six of the eight patients received a follow-up biopsy after therapy.

RESULTS

The histological grade of the International Study of Kidney Disease in Children (ISKDC) was improved in all six patients who received a follow-up biopsy (pre-therapy, four grade IIIa and two grade IIIb; post-therapy, one grade I and five grade II) and it was statistically significant (p = 0.031). The activity index was significantly decreased after therapy (8.3+/-1.6 vs. 3.5+/-1.5, p = 0.031), and the chronicity index (0.5+/-0.5 vs. 0.7+/-1.0) and tubulointerstitial (TI) scores (1.5+/-1.3 vs. 0.8+/-1.6) did not change. There was a reduction in proteinuria from 3.2+/-2.3 to 0.1+/-0.1 g/m2/day (p = 0.008) and renal function remained normal in all patients after therapy. However, one patient showed CyA-induced nephrotoxicity at a second biopsy. After an average follow-up period of 3.8 years, six patients showed normal urine and renal function, and two showed minor urinary abnormalities.

CONCLUSION

This study suggests that CyA therapy is effective in reducing proteinuria, which is a known risk factor for the development of renal insufficiency in HSPN and may regress the renal pathology in patients with nephrotic-range proteinuria.

Impact of cyclosporin on podocyte ZO-1 expression in puromycin aminonucleoside nephrosis rats

Puromycin aminonucleoside (PAN)-induced nephrosis is a well-described model of human idiopathic nephrotic syndrome, but the mechanism of PAN's effect is not completely understood. To investigate whether proteinuria in the PAN model is associated with an alteration of zonula occludens-1 (ZO-1) expression within the glomeruli, and whether cyclosporin A (CsA) has an effect on proteinuria and ZO-1 expression in this model, eighteen Sprague Dawley (SD) rats were assigned into three groups. Twelve rats received a single intraperitoneal injection of PAN (15 mg/100 g). The other six rats received an equal volume of saline (normal control group; control). CsA solution was administered intraperitoneally once a day for 20 days after the PAN injection (n=6, PAN+CsA). The remaining six rats received PAN, but they didn't receive CsA (n=6, PAN). Compared to control rats (35.1+/-5.4 mg/day), the 24-hour urinary protein excretion on day 18 was significantly higher in the PAN rats (1021.9+/-128.9 mg/day, p<0.01), and the CsA treatment partly reversed the increase in proteinuria in the PAN rats (556.4+/-102.3 mg/day, p<0.05). Glomerular ZO-1 protein expressions were significantly increased in the PAN rats as compared to the control group on day 20 (176%, p<0.01). CsA treatment for 20 days in the PAN rats inhibited the increase in ZO-1 protein expression by 71.1% (p<0.05). CsA treatment significantly diminished the glomerular ZO-1 expression in the PAN rats as assessed by immunohistochemistry. CsA treatment significantly reduced proteinuria and the diminished glomerular ZO-1 expression in a PAN nephrosis rat model. These findings suggest the potential role of the slit diaphragm associated proteins in the development of the nephrotic syndrome, and CsA decreased the proteinuria probably by a direct action on the expression of these proteins in podocytes. Further investigations are needed to clarify the role of slit diaphragm associated proteins in the development of PAN nephrosis.

Focal segmental glomerulosclerosis in nephrotic adults: presentation, prognosis, and response to therapy of the histologic variants

The histopathologic diagnosis of primary focal segmental glomerulosclerosis (FSGS) has come to include a number of histologic lesions (variants), but the prognostic significance of these discrete lesions is controversial because published information regarding the presentation, course, and response to treatment is limited. A retrospective analysis was conducted of 87 nephrotic adult patients with biopsy-proven primary FSGS. Patients were categorized on the basis of histologic criteria into those with a classic scar (36 patients), the cellular or collapsing lesion (40 patients), or the tip lesion (11 patients) of FSGS to evaluate differences in presentation, response to therapy, and clinical outcomes. The clinical features at biopsy were similar among the three groups with the exception that patients with the tip lesion were older and patients with the collapsing lesion had more severe proteinuria. Over the course of follow-up, 63% of patients treated attained remission and the response to steroid therapy was similar among the groups (classic scar 53% versus collapsing lesion 64% versus tip lesion 78%; P = 0.45). The overall renal survival was significantly better for patients who entered remission compared with patients who did not enter remission (92% versus 33% at 10 yr; P < 0.0001). The renal survival at 10 yr for patients who entered remission was similar among the three groups (classic scar 100% versus tip lesion 100% versus collapsing lesion 80%; P = 0.61). In patients who did not enter remission, the renal survival at 10 yr was significantly worse for patients with collapsing lesion and tip lesion (classic scar 49% versus tip lesion 25% versus collapsing lesion 21%; P = 0.002). In conclusion, the prognosis for nephrotic FSGS patients who enter remission is excellent regardless of the histologic lesion. Because the remission rate after treatment is similar among patients with the histologic variants, response to therapy cannot be predicted on the basis of histology alone. Thus, nephrotic patients with primary FSGS should receive a trial of therapy irrespective of the histologic lesion when not contraindicated.

[Relativity of nuclear factor-kappaB (P65/Rel-A) and angiotensin II type 1 receptor expression in early stage of lesions of adriamycin nephrosis in young rats and the effects of intervention]

OBJECTIVE

To investigate the trend and potential pathogenic role of nuclear factor (NF)-kappaB P(65)/Rel-A mRNA and angiotensin-II (AngII) receptor type 1 (AT(1)) proteins expression, and the relativity between them in early stage of renal tubulointerstitial lesions in young rats with adriamycin nephrosis and the interfering effects of treatment with angiotensin converting enzyme inhibitor (ACEI) benazepril and ACEI combined with AngII type 1 receptor antagonist (AT(1)RA) Losartan.

METHODS

Male young Wistar rats with adriamycin nephrosis were used as experimental models. At different time points (weeks 1, 2, and 3 in early nephritic phase, the urinary protein and blood biochemical parameters were measured, and P(65)/Rel-A mRNA was detected; AT(1) protein expression was determined by in situ hybridization and immunohistochemical methods. The relativity between them was evaluated.

RESULTS

In the early phase of tubulointerstitial lesions, following adriamycin injection and proteinuria aggravated progressively, at week 3, the proteinuria level had reached heavy proteinuria (123.2 +/- 7.7 mg/24 h). The serum parameters reflecting renal function were elevated. The inflammatory cells infiltrated into renal tissues, especially in tubulointerstitial regions, were increased markedly. Swelling of tubular epithelial cells, broadened tubulointerstitial areas, and protein casts in tubule were observed. In situ hybridization and immunochemical staining showed that AT(1) protein was expressed in tubular epithelial cell cytoplasm and on nuclear membranes (AT(1): 1st week 19.8 +/- 1.1%, 2nd week 25.0 +/- 2.6%, 3rd week 37.1 +/- 1.0% (control: 10.3 +/- 0.8%, 10.4 +/- 1.6%, 10.2 +/- 1.5%); and P(65)/Rel-A mRNA expression in the same locations was upregulated. P(65)/Rel-A translocation from cytoplasm into nucleus increased markedly simultaneously. The positive signal of hybridization dominated in cytoplasm gradually became dominant in the nuclei as the pathological changes progressed. The semiquantitative expression of P(65)/Rel-A was 24.0 +/- 3.3% at week 1, 34.2 +/- 2.4% at week 2, 39.9 +/- 6.4% at week 3, while the values of controls were 8.5 +/- 0.4%, 8.7 +/- 1.0%, and 8.4 +/- 0.9%, respectively. There was a positive correlation between AT(1) and P(65)/Rel-A expression in localization and time phase (r = 0.857, P < 0.01). However, the tendency of those factor's expression was all decreased in each treated group, the semiquantitative results were AT(1): 14.6 +/- 2.1%, 13.7 +/- 2.3%, 11.4 +/- 1.1%; P(65)/Rel-A: 18.5 +/- 3.4%, 22.8 +/- 1.6%, 26.7 +/- 4.9% at 1, 2, 3 weeks in ACEI treated group; AT(1): 12.4 +/- 1.5%, 11.1 +/- 1.0%, 10.3 +/- 0.8%; P(65)/Rel-A: 17.9 +/- 5.0%, 21.3 +/- 6.0%, 22.5 +/- 2.5% in AT(1)RA (Losartan) group, respectively. The significant difference were observed between all groups in different time points (P < 0.05).

CONCLUSIONS

The present study suggested that NF-kappaB (P(65)/Rel-A) mRNA expression and its activity was enhanced significantly that synchronized with aggravating injures in tubulointerstitial lesions initial period induced by proteinuria-loading in nephrotic young rats. This tendency was related with AngII and its receptors system that may accelerate lesions progressing in many renal diseases.

Oxidative stress in a rat model of nephrosis can be quantified by electron spin resonance

The pathogenesis of nephrotic syndrome is not clear. In this study, we used electron spin resonance (ESR) to evaluate levels of reactive oxygen species in rats with puromycin aminonucleoside (PAN)-induced nephrosis. Twenty-six Wistar rats were divided into four groups: (1) PAN treated, (2) PAN treated and alpha-tocopherol supplemented, (3) supplemented with alpha-tocopherol only, (4) control. On day 9, urinary protein excretion was measured. On day 10, all animals were sacrificed with retrograde perfusion via the aorta to obtain renal venous perfusates. The signal intensities of ascorbate radicals in the perfusates were determined by ESR. After perfusion, the kidneys were isolated and sieved to obtain glomeruli for determination of glomerular thiobarbituric acid-reactive substance (TBArs) and alpha-tocopherol. Urinary protein excretion by PAN-treated rats increased significantly on day 9 and was reduced by alpha-tocopherol supplementation. The ascorbate radical intensity and glomerular TBArs level were higher in PAN-treated than in control rats and were both suppressed to control levels by alpha-tocopherol supplementation. There were positive correlations between ascorbate radical intensity and the daily urinary protein, as well as between ascorbate radical intensity and the glomerular TBArs level. Hence, it is possible to quantify oxidative stress due to PAN nephrosis by ESR. Our findings suggest that lipid peroxidation plays an important role in the pathogenesis of proteinuria in PAN-treated rats.

Antifibrotic effect of the Chinese herbs, Astragalus mongholicus and Angelica sinensis, in a rat model of chronic puromycin aminonucleoside nephrosis

Nephrotic syndrome has long been treated in China with two herbs, Astragalus mongholicus and Angelica sinensis, which may have antifibrotic effects.

METHODS

Rats with chronic puromycin-induced nephrosis were treated with Astragalus and Angelica 3 mL/d (n = 7) or enalapril 10 mg/kg/d (n = 7). Normal control rats (n = 7) received saline rather than puromycin, and an untreated control group (n = 7) received puromycin but no treatment. After 12 weeks, stained sections of the glomerulus and tubulointerstitium were evaluated for injury. Immunohistochemistry staining measured extracellular matrix components, transforming growth factor-beta1 (TGFbeta1), osteopontin, ED-1-positive cells, and alpha-actin. TGFbeta1 mRNA was assessed by in situ hybridization. Renin, ACE activity, angiotensin, and aldosterone were measured by radioimmunoassay or colorimetry. In the untreated rats, chronic renal injury progressed to marked fibrosis at 12 weeks. Astragalus and Angelica significantly reduced deterioration of renal function and histologic damage. Expressions of type III and IV collagen, fibronectin, and laminin also decreased significantly. This anti-fibrotic effect was similar to that of enalapril. The herbs had no effect on the renin-angiotensin system but did reduce the number of ED-1-positive, and alpha-actin positive cells and expression of osteopontin compared to untreated controls. The combination of Astragalus and Angelica retarded the progression of renal fibrosis and deterioration of renal function with comparable effects of enalapril. These effects were not caused by blocking the intrarenal renin-angiotensin system, but associated with suppression of the overexpression of TGFbeta1 and osteopontin, reduction of infiltrating macrophages, and less activation of renal intrinsic cells [corrected].

Ganoderma lucidum suppresses endothelial cell cytotoxicity and proteinuria in persistent proteinuric focal segmental glomerulosclerosis (FSGS) nephrosis

A persistent proteinuria is commonly observed in nephrotic patient with focal segmental glomerulosclerosis (FSGS) under treatment with prednisolone+/-cyclophosphamide or with vasodilators (ACEI+AII receptor antagonist, calcium channel blocker and antiplatelet agent). Fourteen such patients with persistent proteinuria were subject to be treated with Ganoderma lucidum. Initial study revealed an enhanced endothelial cell cytotoxicity induced by patient's serum, and an altered immunocirculatory balance with predominant proinflammatory cytokine TNF alpha activity in the presence of defective anti-inflammatory cytokine interleukin-10. Treatment with Ganoderma lucidum suppressed endothelial cell cytotoxicity, restored immunocirculatory balance and successfully suppressed proteinuria in all of these 14 patients.

Inter-individual differences in anti-proteinuric response to ACEi in established adriamycin nephrotic rats are predicted by pretreatment renal damage

ACE inhibition (ACEi) reduces proteinuria and provides reno-protection, but not all subjects benefit from ACEi. Individual differences in the reduction in proteinuria at the onset of treatment and in residual proteinuria during therapy predict differences in renal outcome. The present study investigated whether individual differences in the anti-proteinuric efficacy of ACEi are explained by differences in the severity of pretreatment renal structural damage and whether differences in the level of residual proteinuria during therapy are explained by the severity of renal structural damage at that time, in adriamycin nephrosis in the rat. Pretreatment renal structural damage was assessed in biopsies 6 weeks after exposure to adriamycin (2 mg/kg iv). Then ACEi (75 mg/l lisinopril, n = 23) or vehicle (n = 10) was administered; renal biopsies were repeated after stabilization of the anti-proteinuric response (week 8). Early renal damage (interstitial alpha-smooth muscle actin expression and macrophage accumulation) and established lesions [focal glomerulosclerosis (FGS) and interstitial fibrosis] were scored. During ACEi, proteinuria fell from 834 (487-851) mg/24 h pretreatment to 153 (66-265) mg/24 h at week 8 (p < 0.05); FGS stabilized from 27 (4-70) arbitrar units (AU) pretreatment to 26 (4-84) at week 12, whereas the vehicle did not affect proteinuria, resulting in progressive FGS: 18 (10-26) AU pretreatment versus 88 (46-130) at week 12 (p < 0.05). All parameters of pretreatment damage significantly predicted the anti-proteinuric response. Residual proteinuria during ACEi correlated significantly with renal structural damage parameters at that time. Pretreatment renal damage also predicted renal outcome during extended treatment. Thus, in this experimental setting, in rats with the same renal disorder and the same duration of disease, individual differences in pretreatment renal damage, albeit relatively modest, explain individual differences in renal responsiveness to ACEi. This implies that the limits of the efficacy of ACEi are set by prevalent renal damage. Further studies into the mechanisms of individual resistance to the anti-proteinuric action of ACEi are needed to develop additive intervention strategies.

Effect of grape seed extract on puromycin-aminonucleoside-induced nephrosis in rats

Recent studies indicate that an excessive production of oxidants plays an important role in the pathogenesis of glomerular disease. Grape seed extract (GSE) is a potent antioxidant, and the aim of this pilot study was to evaluate its effect on puromycin-aminonucleoside (PAN)-induced nephrosis in rats. Fifty Sprague-Dawley rats were divided into five groups. Groups 1 and 2 rats received water from day 0 to day 30. Rats in groups 3, 4, and 5 received GSE at 10 mg/100g of body weight (BW), which was started on day 0, 6, and 3 of the experiment, respectively. In group 5 animals the GSE dose was increased (40 mg/100g BW) on day 9. Intraperitoneal dextrose (group 1) or PAN 15 mg/100g BW (groups 2-5) was administered on day 3. Urine and blood specimens were collected at regular intervals, and the comparison between the various groups was made by analysis of variance (ANOVA). Rats in all study groups (groups 3-5) showed a decrease in urine protein and serum cholesterol and triglyceride levels, which was statistically significant in group 3 animals. No significant changes were noted in serum albumin and creatinine levels. In conclusion, GSE administration decreases urine protein excretion and serum cholesterol and triglyceride levels in rats with PAN-induced nephrosis.

Treatment of idiopathic nephrosis by immunophillin modulation

Until 1985, glucocorticoids and cytotoxic drugs were the only treatments available for idiopathic nephrotic syndrome (nephrosis), that is, minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS). Trials of cyclosporine (CsA) treatment of nephrosis, the rationale of which was based on pathophysiologic considerations, have shown that this immunophillin modulator is effective in inducing and maintaining remission in patients suffering from idiopathic nephrotic syndrome. It appears that the best results, in the order of 80% remission rate, are obtained in steroid-sensitive cases, essentially MCD, and that in steroid-resistant FSGS the drug obtains remission in no more than 20% of the cases. Addition of glucocorticoids increases the success rate to approximately 30% of cases. Renal toxicity is proportional to previous impairment of renal function, primary renal disease (FSGS vs MCD) dosage >5.5 mg/kg/day and duration of treatment. The better bioavailability of the new formulation of CsA (Neoral), implies that the former dosage recommendations be reconsidered for distinctly lower figures. Repeat renal biopsy after 1 year of continuous CsA treatment is advisable, as stable serum creatinine levels may be falsely reassuring. CsA dependency is the rule during the first year of treatment. However, in some 25% of cases stable remission may be maintained after slow tapering off following 3-4 years of treatment. Other immunophillin modulators have been tried in the treatment of idiopathic nephrotic syndrome. Despite few preliminary reports indicating some success of tacrolimus the effects of this drug do not seem convincingly superior to CsA in terms of remission rate, toxicity and dependency. Rapamycin has not been tried in the treatment of nephrosis. Anecdotal cases of de novo FSGS induced by rapamycin in transplanted patients might indicate that this drug is in fact contraindicated in the treatment of nephrosis.

Effects of anti-proteinuric therapy with angiotensin-converting-enzyme inhibition on renal protein catabolism in the adriamycin-induced nephrotic rat

A direct consequence of glomerular protein leakage is an increased exposure of proximal tubular cells to proteins. The aim of the present study was to examine whether chronic proteinuria affects the tubular handling of proteins and whether anti-proteinuric therapy by angiotensin-converting-enzyme (ACE) inhibition restores this tubular function. Renal uptake and catabolic rate of the low-molecular-weight protein (LMWP) myoglobin was determined in anaesthetized control and adriamycin-induced nephrotic rats by external counting after radiolabelling. Proteinuria correlated with the uptake as well as the catabolism of myoglobin. The higher the proteinuria, the lower was the renal uptake of myoglobin (r =0.72, P =0.002). Also, the catabolic rate of myoglobin (r =0.80, P =0.0002) was lower with increasing severity of proteinuria. During treatment with the ACE inhibitor lisinopril, proteinuria was lowered by 79+/-9% (mean+/-S.E.M.). Renal uptake and catabolic rate of the LMWP were not restored by ACE inhibition. The catabolic rate of myoglobin was even decreased further with 48+/-5% compared with pretreatment levels. In summary, adriamycin-induced proteinuria is associated with a lower uptake and a lower catabolic rate of LMWP in the proximal tubule. ACE inhibition lowers proteinuria, but does not restore the affected LMWP uptake and rate of catabolism. The rate of LMWP catabolism is even decreased further. In contrast, the urinary excretion of N -acetyl glucosaminidase, the tubular marker of toxicity, was effectively returned to normal levels during ACE inhibition. Taken together, the data suggest that proteinuria is toxic for the proximal tubular cells and that ACE inhibition protects the remaining functional tubular cells directly against destruction through decreasing hypercatabolism.

Involvement of renal ACE activity in proteinuria-associated renal damage in untreated and treated adriamycin nephrotic rats

Proteinuria is assumed to play a pathogenetic role in progressive renal damage. Angiotensin-converting enzyme (ACE) inhibition reduces proteinuria and provides renoprotection. This suggests that ACE activity might play a pathogenetic role in the development of proteinuria-induced renal structural damage. We investigated this hypothesis in untreated and treated established adriamycin nephrosis, a model of proteinuria-induced renal damage. In a time-course experiment, the development of renal structural damage in untreated adriamycin nephrotic rats was paralleled by a significant rise in renal ACE activity. Moreover, on cross-sectional analysis, a consistent positive correlation between renal, but not plasma, ACE activity and proteinuria, focal glomerulosclerosis and interstitial injury was present. Notably, these associations were present, not only in the untreated condition, but also during intervention with either ACE inhibition or AT(1)-receptor antagonism. Interestingly, we found that higher renal ACE activity is associated with more severe renal damage for a given amount of proteinuria, suggesting that renal ACE activity may be either a permissive or a promoting factor in the processes by which proteinuria eventually leads to renal structural damage. This relationship was abolished by renin-angiotensin system (RAS)-blockade, suggesting that RAS-mediated effects are involved in the relationship between renal ACE activity and proteinuria-induced renal damage. In conclusion, in untreated as well as treated adriamycin nephrotic rats, renal ACE activity is closely associated with renal outcome. This association appears to be independent of the specific mode of blockade of the RAS. Renal ACE activity is a consistent marker of individual differences in proteinuria-associated renal damage: further studies are needed to investigate a possible pathogenetic role in renal damage.

Retinoids regulate the repairing process of the podocytes in puromycin aminonucleoside-induced nephrotic rats

The foot processes forming the slit diaphragm are disrupted in diseases associated with proteinuria. Although they are often repairable, regulators for the repairing process remain unknown. By extrapolating from the fact that vitamin A is essential for the nephrogenesis, this study examined whether or not injured podocytes in the middle of the repairing process require retinaldehyde dehydrogenase type 2 (RALDH2), one of the key enzymes to produce all-trans-retinoic acid (ATRA). RALDH2 was dramatically upregulated in podocytes of puromycin aminonucleoside-induced nephrosis (PAN nephrosis) rats. On day 5 of PAN nephrosis, RALDH2 showed the remarkable induction, whereas glomerular expression levels of nephrin and midkine, one of the ATRA target genes, were downregulated. Daily administration of ATRA ameliorated proteinuria, which was accompanied by the improvement in the effacement of the foot processes and by the induction of nephrin and midkine. In contrast, recovery from PAN nephrosis was delayed in rats fed with a vitamin A-deficient diet. Consistently, the promoter region of human nephrin gene (NPHS1) contained three putative retinoic acid response elements (RARE) and showed the enhancer activity in response to ATRA in a dose-dependent manner. This transcriptional activation was regulated through the receptors for retinoids because BMS-189453, an antagonist to the retinoid receptors, counteracted it in a dose-dependent manner. In conclusion, active metabolites of vitamin A, especially ATRA produced by RALDH2 play relevant roles during the repairing process of injured podocytes. The results obtained from PAN nephrosis rats might be applicable to human renal diseases.

The genetic basis of FSGS and steroid-resistant nephrosis

Studies of Mendelian forms of focal segmental glomerulosclerosis (FSGS) and nephrotic syndrome have provided new insights into the mechanism of these diseases. Congenital nephrotic syndrome and familial forms of FSGS form a spectrum of podocyte diseases of varying severity and age of onset. Mutations in both nephrin gene (NPHS1) alleles lead to congenital nephrosis, podocyte foot process efacement, and loss of slit-diaphragm structure. Mutations in both podocin gene (NPHS2) alleles lead to a wide range of human disease, from childhood-onset steroid-resistant FSGS and minimal change disease to adult-onset FSGS. Dominantly inherited mutations in ACTN4, the alpha-actinin-4 gene, can lead to a slowly progressive adult-onset form of FSGS. In addition, FSGS is observed as part of several rare multisystem inherited syndromes. Here we review recent progress in understanding the genetic basis of FSGS in humans.

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

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

A hemodynamically mediated mechanism of renal disease progression in severe glomerulonephritides or nephrosis

Glomerular endothelial cell (GEC) dysfunction due to oxidative stress and enhanced proinflammatory cytokines plays an important role in inducing proteinuria and procoagulant activity, namely blood hypercoagulability, hyperviscosity and local intravascular coagulation and altered hemorheology in NS. A dysfunctioning GEC releases fewer endothelium-dependent vasodilators but produces more vasoconstrictors. Severe intrarenal hemodynamic alteration associated with hemodynamic maladjustment with preferential constriction at the efferent arteriole has been uniquely implicated in severe GN and NS-FSGS. Such a constriction exerts three significant hemodynamic impacts. Proximal to the efferent arteriolar constriction, it induces (i) an overestimated GFR due to hyperfiltration and (ii) an elevated intraglomerular hydrostatic pressure. Distal to the efferent arteriolar constriction, it (iii) exaggeratedly reduces PTCF which correlates with the TIF.

Treatment of glomerular endothelial dysfunction in steroid-resistant nephrosis with Ganoderma lucidum, vitamins C, E and vasodilators

Glomerular endothelial dysfunction is believed to be responsible for the proteinuria and nephronal damage, namely tubulointerstitial fibrosis and glomerulosclerosis, observed in severe nephrosis such as focal segmental glomerulosclerosis. A dysfunctioning glomerular endothelium is likely to be induced by oxidative stress and oxidized LDL as well as altered immunocirculatory balance with a defective anti-inflammatory pathway. A defective release of vasodilator inconjunction with enhanced production of angiotensin II induces hemodynamic maladjustment by preferential constriction at the efferent arteriole. Such a hemodynamic maladjustment exerts two significant hemodynamic impacts. Close to the efferent constriction, it induces intraglomerular hypertension and glomerulosclerosis. Far from the efferent constriction, it reduces peritubular capillary flow, which eventually leads to tubulointerstitial fibrosis. Treatment with a vasodilator improves the hemodynamic maladjustment but does not completely suppress proteinuria. A successful suppression of proteinuria is accomplished by using Ganoderma lucidum and vitamins C and E. The beneficial effect of Ganoderma lucidum appears to be multifactorial, including the modulation of immunocirculatory balance, antilipid, vasodilator, antiplatelet and improved hemorheology. Together with vitamins C and E, this helps to neutralize oxidative stress and suppress the toxic effect to the glomerular endothelial function.

Renoprotective effects of VPI versus ACEI in normotensive nephrotic rats on different sodium intakes

BACKGROUND

Control of blood pressure (BP) and optimal reduction of proteinuria (Uprot) are necessary for long-term renoprotection. Unfortunately, angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II (Ang II) antagonists are not effective during sodium repletion. Vasopeptidase inhibitors (VPI) cause dual inhibition of ACE and neutral endopeptidase, the latter resulting in decreased atrial natriuretic peptide (ANP) breakdown and thus enhanced natriuresis. Therefore, in contrast with ACEI, VPI may be effective during high sodium intake.

METHODS

To test this hypothesis, the renoprotective actions of the new VPI gemopatrilat (GEM) were studied during low (0.05% NaCl) and high (3.0% NaCl) sodium diets in normotensive Wistar rats with established adriamycin nephrosis. The ACEI lisinopril (LIS) was used as control. Rats received either GEM (0.3 mg/g chow), an equihypotensive dose of LIS (75 mg/L drinking water), or vehicle (VEH) from week 6 (that is, established Uprot) until sacrifice. The effect of therapy was monitored by measuring systolic BP and Uprot (weekly) and structural renal damage at the end of study (week 16).

RESULTS

During low sodium, GEM effectively reduced Uprot (-48 +/- 4%), but LIS was more effective (-80 +/- 2%), while Uprot slightly increased in VEH (+23 +/- 2%). The focal glomerulosclerosis (FGS) score after GEM (38 +/- 14) was lower than in the VEH group (79 +/- 27), although this was not significant. LIS (18 +/- 6) reduced FGS significantly. Remarkably, on high sodium, GEM was completely ineffective in reducing BP, Uprot and structural renal injury, just like LIS.

CONCLUSIONS

The renoprotective actions of VPI depend on dietary sodium intake in normotensive nephrotic rats: therapeutic efficacy is fully blunted by a high sodium diet. During a low sodium diet, gemopatrilat was renoprotective, but less effective than lisinopril. Whether higher doses of the VPI could improve its renoprotective efficacy remains to be elucidated.

Addition of AT1 blocker fails to overcome resistance to ACE inhibition in adriamycin nephrosis

BACKGROUND

Angiotensin-converting enzyme (ACE) inhibitors provide renoprotection, but there is considerable interindividual variability in therapeutic efficacy, with residual proteinuria and progressive renal function loss in many individuals. This requires additional strategies to optimize therapy response, particularly for individuals with a poor response to ACE inhibition. We studied whether co-treatment with an angiotensin II subtype 1 (AT1) receptor antagonist (AII-A) improves the individual antiproteinuric response of maximal ACE inhibition in established adriamycin nephrosis.

METHODS

Rats were instituted on lisinopril (75 mg/L) six weeks after disease induction. After two weeks rats were re-stratified for residual proteinuria to continue this regimen, to a higher dose of lisinopril (150 mg/L) or to co-treatment with the AII-A L 158,809 for another four weeks. Groups on monotherapy AII-A and vehicle served as controls (all groups N=15).

RESULTS

Lisinopril lowered proteinuria by 63% from 741 to 246 g/day (range of percentage change -90 to +2%). Neither increasing the dose of the ACE inhibitor nor addition of AII-A to ACE inhibition improved the antiproteinuric efficacy on a group or individual level: non-responders remained non-responders. All drug categories reduced hard end-points of focal glomerulosclerosis to a similar degree.

CONCLUSIONS

ACE inhibition has variable renal protective efficacy in the adriamycin model. Neither increasing the dose of the ACE inhibitor beyond the optimal level nor co-treatment with AII-A overcome the individual therapy resistance. Thus, in established adriamycin nephrosis, blockade of the renin-angiotensin system at two different levels offers no additional benefit over ACE inhibition alone, either on the group or individual level.

Temocapril, a long-acting non-SH group angiotensin converting enzyme inhibitor, modulates glomerular injury in chronic puromycin aminonucleoside nephrosis

The purpose of the present study was to determine whether chronic administration of temocapril, a long-acting non-SH group angiotensin converting enzyme (ACE) inhibitor, reduced proteinuria, inhibited glomerular hypertrophy and prevented glomerulosclerosis in chronic puromycin aminonucleoside (PAN) - induced nephrotic rats. Nephrosis was induced by injection of PAN (15mg/100g body weight) in male Sprague-Dawley (SD) rats. Four groups were used, i) the PAN group (14), ii) PAN/temocapril (13), iii) temocapril (14) and iv) untreated controls (15). Temocapril (8 mg/kg/day) was administered to the rats which were killed at weeks 4, 14 or 20. At each time point, systolic blood pressure (BP), urinary protein excretion and renal histopathological findings were evaluated, and morphometric image analysis was done. Systolic BP in the PAN group was significantly high at 4, 14 and 20 weeks, but was normal in the PAN/temocapril group. Urinary protein excretion in the PAN group increased significantly, peaking at 8 days, then decreased at 4 weeks, but rose again significantly at 14 and 20 weeks. Temocapril did not attenuate proteinuria at 8 days, but it did markedly lower it from weeks 4 to 20. The glomerulosclerosis index (GSI) was 6.21 % at 4 weeks and respectively 25.35 % and 30.49 % at 14 and 20 weeks in the PAN group. There was a significant correlation between urinary protein excretion and GSI (r = 0.808, p < 0.0001). The ratio of glomerular tuft area to the area of Bowman's capsules (GT/BC) in the PAN group was significantly increased, but it was significantly lower in the PAN/temocapril group. It appears that temocapril was effective in retarding renal progression and protected renal function in PAN neprotic rats.

Effect of ramipril in a patient with glycogen storage disease type I and nephrotic-range proteinuria

We studied the effect of ramipril on urinary protein excretion and arterial pressure in a 27-year-old patient with GSD Ia and heavy proteinuria (2-3 g /24 h). Ramipril therapy resulted in an important reduction of proteinuria (0.3-0.5 g/24 h): no changes were observed in arterial pressure and renal function during the 12-month follow-up. We conclude that treatment with ramipril can be employed effectively and safely in GSD Ia patients with nephrotic-range proteinuria.

IGFs and IGF-binding proteins in short children with steroid-dependent nephrotic syndrome on chronic glucocorticoids: changes with 1 year exogenous GH

OBJECTIVE

Children with steroid-dependent nephrotic syndrome (SDNS), despite being in remission on glucocorticoids, continue to have growth retardation and short stature. The mechanism is uncertain as both chronic glucocorticosteroids and the nephrotic syndrome may independently affect growth. We investigated the changes in the IGFs and IGF-binding proteins (IGFBPs) in a group of short SDNS children, and studied the changes prospectively with 1 year's treatment with GH.

DESIGN AND METHODS

Total and 'free' IGF-I, IGFBP-3 and acid-labile subunit (ALS) were studied in eight SDNS boys (mean age=12.6 years; mean bone age=9.1 years) on long term oral prednisolone (mean dose 0.46 mg/kg per day) before, during, and after, 1 year's treatment with GH (mean dose 0.32 mg/kg per week). Pretreatment comparisons were made with two control groups, one matched for bone age (CBA; mean bone age=9.2 years), and another for chronological age (CCA; mean chronological age=13 years). Subsequently, three monthly measurements of serum and urine IGFBPs were carried out in the GH-treated SDNS patients using Western ligand blot and Western immunoblot.

RESULTS

Pre-treatment serum total IGF-I levels and the IGF-I/IGFBP-3 ratio were elevated significantly in SDNS compared with CBA, and were similar to CCA. Serum free IGF-I levels were elevated significantly compared with both control groups, but serum IGFBP-3 did not differ significantly. Urinary IGFBP-2, IGFBP-3 and ALS were detectable in the SDNS children only. With GH treatment, IGF-I and IGFBP-3, but not IGF-II, increased significantly compared with pre-treatment values, and returned to baseline after cessation of GH treatment. Urinary IGFBPs did not change significantly with GH treatment.

CONCLUSIONS

There is persistent urinary loss of IGFBP-2, IGFBP-3 and ALS in children with SDNS in remission with growth retardation. However, the significant elevation in serum IGF-I suggests that glucocorticoid-induced resistance to IGF is the main factor responsible for the persistent growth retardation in these children. Exogenous GH was able to overcome this resistance by further increasing serum IGF-I.

[Effect of shenfukang on nephropathy rats induced by adriamycin]

Adriamycin-induced nephropathy (AIN) model in rats (mainlining 7.5 mg/kg avoirdupois adiramycine) was adopted to explore the effect of Shenfukang (SFK). The results showed that SFK could remarkably reduce the content of urine protein, cholesterol, creatinine and urinary nitrogen in serum, MDA in serum and renal cortex of AIN model rats. And SFK also could increase the content of album and golbulin in serum, the activities of SOD in serum and renal cortex of AIN model rats.

CONCLUSION

SFK played an important role on AIN.

Effects of LTB4 receptor antagonist on myonephropathic metabolic syndrome: an experimental study

The aims of this study were to determine the involvement of leukocytes in reperfusion injury following acute arterial occlusion and to evaluate the effect of the leukotriene B4 (LTB4), which is a chemical mediator of inflammation, receptor antagonist. We examined the usefulness of LTB4 receptor antagonist, ONO-4057, as a preventative drug for myonephropathic metabolic syndrome (MNMS). The experimental leg ischemic model was developed using Wistar strain rats. The rats were divided into 4 groups. In Group R3, the infra-renal abdominal aorta was clamped for 3 hrs and the right femoral muscle tissue was cut to block the development of a collateral artery. In Group R6, the infra-renal abdominal aorta was clamped for 6 hrs and the right femoral muscle tissue was cut. In Group C, the controls, there was no clamping of the abdominal aorta and the right femoral muscle tissue was cut. In Group M, the medicated group, rats were pretreated with an LTB4 receptor antagonist, ONO-4057, just before reperfusion. Blood serum interleukin-1 (IL-1), interleukin-8 (IL-8), creatine phosphokinase (CPK), and aldolase were measured and compared in each of those 4 groups. We also examined the intercellular adhesion molecule-1 (ICAM-1) expression in various organs (liver, heart and kidney) by immunohistochemistry. We found that IL-1 beta levels were low in all groups. CPK, aldolase and IL-8 levels after reperfusion in Group R6 significantly high compared with the levels in Group C (P < 0.03 about CPK, P < 0.05 about aldolase, and P < 0.05 about IL-8). The levels of CPK, aldolase, and IL-8 in Group M were significantly lower than those in Group R6 (P < 0.02 about CPK, P < 0.04 about aldolase, and P < 0.03 about IL-8). We determined immunohistochemically that the expression of ICAM-1 was positive on endothelial cells at the coronary artery and the small vein in Group R6 and that the expression of ICAM-1 was negative on endothelial cells in Group C. Those data suggested that ICAM-1 may play an important role in the progression of reperfusion injury, and the adhesion of neutrophilic leukocytes on endothelial cells may play a significant role in MNMS. LTB4 receptor antagonist may be useful for preventing reperfusion injury following acute aortic occlusion.

Protection of alpha(3) integrin-mediated podocyte shape by superoxide dismutase in the puromycin aminonucleoside nephrosis rat

Because reactive oxygen species (ROS) are involved in the development of puromycin aminonucleoside nephrosis (PAN), we examined whether superoxide dismutase (SOD) could ameliorate this condition. Phosphatidyl choline-bound SOD (PC-SOD) has higher affinity for the cell membrane than recombinant human SOD (rhSOD). In this study, PC-SOD had a longer half-life in the circulation and also higher affinity to renal fractions (glomerulus, brush border, and tubulus) than rhSOD. PAN was induced in rats with single injections of puromycin aminonucleoside. Rats were divided into four groups: group P, PAN rats without treatment; group PC-T and group rh-T, PAN rats treated with 30,000 U/kg PC-SOD and rhSOD, respectively; and group C, normal controls. The effect of PC-SOD versus rhSOD on PAN was evaluated by morphological podocyte changes (podocyte density along the GBM) and alpha(3) integrin expression at days 4 and 10. Proteinuria was measured over time until day 14. Distribution and quantitation of alpha(3) integrin were studied by confocal laser scan microscopy. On day 4, glomerular ROS was measured by chemiluminescence without stimulation. PC-SOD decreased proteinuria to the control level, but rhSOD only decreased proteinuria by 31%. PC-SOD significantly improved podocyte density (P < 0.05 versus group P). Total alpha(3) integrin expression decreased in the P and rh-T groups at day 4 and then had recovered by day 10, but the polarity of the site of expression did not recover. PC-T preserved both the amount and polarity of integrin expression on days 4 and 10. PC-SOD significantly suppressed ROS generation in PAN (P < 0.05). These findings suggest that alpha(3) integrin regulates glomerular permeability by maintaining podocyte shape and adhesion, which is disrupted by ROS overproduction.

Proinflammatory effects in experimental mesangial proliferative glomerulonephritis of the immunosuppressive agent SDZ RAD, a rapamycin derivative

BACKGROUND/AIM

The new immunosuppressant SDZ RAD, a rapamycin derivative, inhibits growth factor driven cell proliferation. SDZ RAD designed for transplantation may also be a candidate agent to treat inflammatory kidney diseases. Therefore, we investigated the effects of SDZ RAD in two different animal models of glomerulonephritis, in anti- Thy1.1 nephritis and in acute puromycin aminonucleoside (PAN) nephrosis.

METHODS

Eighty-seven male Wistar rats were investigated. Anti-Thy1.1 nephritis: healthy rats (n = 9), SDZ RAD-treated healthy rats (n = 6), nephritic rats (n = 9), SDZ RAD placebo treated nephritic rats (n = 6), SDZ RAD-pretreated nephritic rats (n = 9), and early (n = 6) as well as delayed (n = 6) SDZ RAD-posttreated nephritic rats. PAN nephrosis: healthy rats (n = 6), SDZ RAD-treated healthy rats (n = 6), nephritic rats (n = 12), and SDZ RAD-pretreated nephritic rats (n = 12). In a separate study, 12 male Sprague-Dawley rats were analyzed in anti-Thy1.1 nephritis: healthy rats (n = 3), nephritic rats (n = 3) and pretreated nephritic rats (n = 6). SDZ RAD and SDZ RAD placebo were given at single doses of 2.5 mg/kg body weight per day by gavage. The experiments lasted until days +2 and +9 after induction of anti-Thy1. 1 nephritis and until day +13 in the case of PAN nephrosis.

RESULTS

In anti-Thy1.1 nephritis, SDZ RAD demonstrated marked proinflammatory effects in a time-dependent manner, as reflected by severe focal damage to glomerular histology including inhibition of mesangial cell proliferation, reduction of creatinine clearance, and increase in plasma creatinine levels as well as proteinuria. Almost identical results were obtained in both rat strains. In contrary, SDZ RAD ameliorated significantly the development of PAN nephrosis. Animals pretreated by this agent showed a significant reduction of proteinuria and of glomerular invasion of monocytes/macrophages.

CONCLUSION

Some caution is warranted for the use of SDZ RAD in inflammatory glomerular diseases, since it accentuated glomerular damage induced by anti-Thy1.1 antibodies.

Antiproteinuric effect of calcium antagonists on puromycin-induced experimental nephrosis

Calcium antagonists have a potential for beneficial effects on kidney function unrelated to their antihypertensive action. In this study we have investigated the efficacy of calcium antagonists compounds (verapamil, nifedipine and diltiazem) on reversible acute renal insufficiency, proteinuria and interstitial nephritis induced by the puromycin ammonucleoside (PAN). An increase in blood pressure (BP) was detected on day 14, with no statistical differences in the response to calcium antagonists. Serum creatinine concentration increased to 1.2 mg/dL on day 7 after PAN and decreased to 0.7 mg/dL at 14 days, calcium antagonists shortened the time required to reach baseline or control levels. Calcium antagonists also reduced proteinuria in the PAN-treated animals, in both day 7 and day 14. Differential effects of the antagonists were observed. Verapamil caused a greater reduction (p < 0.01) in proteinuria than nifedipine or diltiazem in day 7. Moreover, verapamil (p < 0.01) and nifedipine (p < 0.01) reduced the total number of interstitial infiltrating leukocytes from 690 to 120 and 425 positive cells/20 high power fields (x63) respectively, by contrast, diltiazem had no effect. We conclude that in this model of PAN nephropathy verapamil is more effective in reducing both proteinuria and the severity of acute interstitial nephritis than either nifedipine or diltiazem. The possible clinical implications of these results remain to be elucidated.

Role of ticlopidine on adriamycin-induced nephropathy

The effect of ticlopidine on rats with adriamycin nephropathy was observed during 26 weeks. In the ticlopidine-treated nephrotic animals (TNG), proteinuria was less than in the untreated nephrotic animals (NG), but this difference was significant only at week 6 (TNG = 47.27 +/- 16.52 versus NG = 100.08 +/- 13.83 mg/24 h, p < 0.01) and week 26 (TNG = 157.00 +/- 28.73 versus NG = 217.00 +/- 21.73 mg/24 h, p < 0.01) after ADR injection. NG presented severe tubulointerstitial abnormalities with a tubulointerstitial lesion index of 3+. No difference in glomerular lesions was observed among the groups (NG median = 6%, TNG median = 4% and TCG median = 2%). The tubulointerstitial lesion index of TNG was less intense (median = 2+) but not different from those of the control groups (CG median = 1+; TCG median = 0+) nor NG (median = 3+). We concluded that the treatment with ticlopidine produced some partially beneficial effects but did not prevent the development of adriamycin-induced nephropathy.

Effects of human alpha-1-acid glycoprotein on aminonucleoside-induced minimal change nephrosis in rats

A minimal change nephrosis was induced in rats by a single intraperitoneal injection of puromycin aminonucleoside (100 mg/kg). This resulted in increased urine protein output, plasma creatinine, blood urine nitrogen, and relative kidney weight. Electronoptically, there was a retraction of the glomerular podocytic foot processes. When human alpha1-acid glycoprotein was injected at 600 mg/kg intravenously on experimental days 6, 7, 8, and 9 into these animals, urine protein output decreased significantly, and the number of podocytic foot processes increased significantly. alpha1-Acid glycoprotein is rich in sialic acid and largely negatively charged. Its therapeutic role in nephrosis, which is characterized by a loss of sialic acid and a loss of negative charge, thereby leading to a loss of permselectivity, is discussed.

Dipyridamole and dilazep suppress oxygen radicals in puromycin aminonucleoside nephrosis rats

BACKGROUND

Reactive oxygen species (ROS) are involved in the pathophysiology of puromycin aminonucleoside (PAN) nephrosis. To elucidate further the role of radicals in PAN nephrosis and the to determine the particular radical species scavenged by dipyridamole (DPM) and dilazep (DZ), we applied chemiluminescence and electron spin resonance (ESR) techniques.

METHODS

Chemiluminescence of glomeruli, which were isolated on day 7 from rats injected with 100 mg kg-1 PAN, was measured with or without scavengers. The inhibitory effects of DPM and DZ on hydroxyl radical adduct formation in the Fenton's reaction were evaluated using ESR.

RESULTS

Chemiluminescence was greater in glomeruli from rats with PAN nephrosis than in the the glomeruli of control rats. This increase was suppressed by superoxide dismutase, catalase, dimethylthiourea and also by DPM and DZ. ESR indicated that DPM and DZ inhibited hydroxyl radical adduct formation with a second-order rate constant of 2.9 x 10(10) and 1.6 x 10(10) (mol L(-1) s(-1) respectively, similar to that of dimethylthiourea.

CONCLUSION

DPM and DZ scavenge hydroxyl radicals, thereby alleviating PAN nephrosis.