A clinical study on the difference among proteinuria components in preeclampsia and pregnancies complicated with chronic nephrosis.

OBJECTIVE: To explore proteinuria components in preeclampsia (PE) and pregnancies complicated with chronic nephrosis (PCCN). METHODS: A case-control study was conducted with 81 PE and 95 PCCN patients and 192 normal pregnancies from April 2016 to March 2018. The results of a 24 h proteinuria test and a proteinuria component analysis (PCA) of all enrolled patients were collected. Statistical analyses of variance and SNK-q were conducted to identify the difference between PE and PCCN in urinary protein components using SPSS 23.0 software. A Pearson test and linear regression were conducted to explore the association between 24 h proteinuria and PCA. RESULTS: Among the PE, PCCN and control groups, the average values of mAlb(2868.5 ± 3119.3 vs 1586.2 ± 3627.0 vs 21.6 ± 23.6), TRF(252.0 ± 280.5 vs 112.9 ± 164.5 vs 3.1 ± 2.7), α1-MG(40.4 ± 40.7 vs 34.0 ± 38.6 vs 10.3 ± 8.0), ß2-MG(1.9 ± 5.1 vs 6.8 ± 15.8 vs 0.9 ± 2.3), and RBP(0.9 ± 1.7 vs 3.1 ± 4.5 vs 0.4 ± 0.7) were significantly different (P＜0.001). According to the SNK-q test, the average value of mAlb and TRF in the PCCN group is lower than that in the PE group, but higher than the control group (P < 0.05). The average value of RBP and ß2-MG in the PCCN group was higher than the PE and control groups (P < 0.05). The mAlb, TRF, and α1-MG values separately had a significant correlation with the 24 h proteinuria value in PE. The linear regression equation was 24 h proteinuria value = 0.891*mAlb + 5.969*TRF + 1742.378. The mAlb, TRF, α1-MG, ß2-MG, and RBP values separately had a significant correlation with the 24 h proteinuria value in PCCN and a linear regression equation of PCCN was as follows: 24 h proteinuria value = 15.148*TRF + 0.571*mAlb. CONCLUSIONS: The proteinuria components of PE and PCCN patients were different in the elevated ß2-MG and RBP. The PCA could be a suitable test for qualitative analysis and an antidiastole for PE and PCCN.

Trpc6 inactivation confers protection in a model of severe nephrosis in rats.

Mutations in canonical transient receptor potential-6 (TRPC6) channels give rise to rare familial forms of focal and segmental glomerulosclerosis (FSGS). Here we examined a possible role for TRPC6 in the progression of chronic puromycin aminonucleoside (PAN) nephrosis in Sprague-Dawley rats, a classic model of acquired nephrotic syndromes. We used CRISPR/Cas9 technology to delete a 239-bp region within exon 2 of the Trpc6 gene (Trpc6del allele). Trpc6del/del rats expressed detectable Trpc6 transcripts missing exon 2, and TRPC6 proteins could be detected by immunoblot of renal cortex. However, the abundance of Trpc6 transcripts and TRPC6 protein in renal cortex was much lower than in Trpc6wt/wt littermates, and functional TRPC6 channels could not be detected in whole-cell recordings from glomerular cells cultured from Trpc6del/del animals, possibly because of disruption of ankyrin repeats 1 and 2. During the chronic phase of PAN nephrosis, Trpc6del/del rats had reduced urine albumin excretion, reduced serum cholesterol and triglycerides, and improved azotemia compared to wild-type Trpc6wt/wt littermates. Glomerulosclerosis was severe during chronic PAN nephrosis in Trpc6wt/wt rats but was markedly reduced in Trpc6del/del littermates. Trpc6del/del animals also had less severe tubulointerstitial fibrosis as assessed by several biochemical and histological analyses, as well as reduced foot process effacement and glomerular basement thickening compared to Trpc6wtt/wt controls. None of the manipulations in this study affected the abundance of TRPC5 channels in renal cortex. TRPC3 was increased in PAN nephrosis and in Trpc6del/del rats. These data support a role for TRPC6 channels in driving an acquired form of secondary FSGS. KEY MESSAGES: We examined aminonucleoside nephrosis in rats with wild type and inactivated TRPC6. TRPC6 channels were inactivated by CRISPR/Cas9 editing of the Trpc6 gene. TRPC6 inactivation reduced albuminuria in the chronic but not the acute phase. TRPC6 inactivation reduced glomerulosclerosis and ultrastructural changes. TRPC6 inactivation also reduced interstitial changes and renal fibrosis.

Clinico-pathological findings in a striped dolphin (Stenella coeruleoalba) affected by rhabdomyolysis and myoglobinuric nephrosis (capture myopathy).

A striped dolphin (Stenella coeruleoalba) calf stranded alive because of a Salter-Harris fracture type 1 of a caudal vertebra and remained in a provisional rehabilitation facility for 3 days where the fracture stabilization was attempted, but he died the day after bandaging. Serum and urine samples were collected during hospitalization (days 1, 2 and 3 serum and day 2 urine). Serum analysis showed increased urea, alanine transaminase, aspartate transaminase, and serum amyloid A values, while creatinine was below the lower limit. Urine analysis showed urinary protein-to-creatinine ratio of 5.3 with glomerular proteinuria. Postmortem analyses demonstrated a severe rhabdomyolysis and myoglobinuric nephrosis, suggestive of capture myopathy syndrome. We report, for the first time, the clinico-pathological changes during this condition in a striped dolphin.

Thrombin-Induced Podocyte Injury Is Protease-Activated Receptor Dependent.

Nephrotic syndrome is characterized by massive proteinuria and injury of specialized glomerular epithelial cells called podocytes. Studies have shown that, whereas low-concentration thrombin may be cytoprotective, higher thrombin concentrations may contribute to podocyte injury. We and others have demonstrated that ex vivo plasma thrombin generation is enhanced during nephrosis, suggesting that thrombin may contribute to nephrotic progression. Moreover, nonspecific thrombin inhibition has been shown to decrease proteinuria in nephrotic animal models. We thus hypothesized that thrombin contributes to podocyte injury in a protease-activated receptor-specific manner during nephrosis. Here, we show that specific inhibition of thrombin with hirudin reduced proteinuria in two rat nephrosis models, and thrombin colocalized with a podocyte-specific marker in rat glomeruli. Furthermore, flow cytometry immunophenotyping revealed that rat podocytes express the protease-activated receptor family of coagulation receptors in vivo High-concentration thrombin directly injured conditionally immortalized human and rat podocytes. Using receptor-blocking antibodies and activation peptides, we determined that thrombin-mediated injury depended upon interactions between protease-activated receptor 3 and protease-activated receptor 4 in human podocytes, and between protease-activated receptor 1 and protease-activated receptor 4 in rat podocytes. Proximity ligation and coimmunoprecipitation assays confirmed thrombin-dependent interactions between human protease-activated receptor 3 and protease-activated receptor 4, and between rat protease-activated receptor 1 and protease-activated receptor 4 in cultured podocytes. Collectively, these data implicate thrombinuria as a contributor to podocyte injury during nephrosis, and suggest that thrombin and/or podocyte-expressed thrombin receptors may be novel therapeutic targets for nephrotic syndrome.

Nephrotic range proteinuria as a strong risk factor for rapid renal function decline during pre-dialysis phase in type 2 diabetic patients with severely impaired renal function.

BACKGROUND: Proteinuria is an established risk factor for progression of renal disease, including diabetic nephropathy. The predictive power of proteinuria, especially nephrotic range proteinuria, for progressive renal deterioration has been well demonstrated in diabetic patients with normal to relatively preserved renal function. However, little is known about the relationship between severity of proteinuria and renal outcome in pre-dialysis diabetic patients with severely impaired renal function. METHODS: 125 incident dialysis patients with type 2 diabetes were identified. This study was aimed at retrospectively evaluating the impact of nephrotic range proteinuria (urinary protein-creatinine ratio above 3.5 g/gCr) on renal function decline during the 3 months just prior to dialysis initiation. RESULTS: In total, 103 patients (82.4 %) had nephrotic range proteinuria. The median rate of decline in estimated glomerular filtration rate (eGFR) in this study population was 0.98 (interquartile range 0.51-1.46) ml/min/1.73 m(2) per month. Compared to patients without nephrotic range proteinuria, patients with nephrotic range proteinuria showed significantly faster renal function decline (0.46 [0.24-1.25] versus 1.07 [0.64-1.54] ml/min/1.73 m(2) per month; p = 0.007). After adjusting for gender, age, systolic blood pressure, serum albumin, calcium-phosphorus product, hemoglobin A1c, and use of an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker, patients with nephrotic range proteinuria showed a 3.89-fold (95 % CI 1.08-14.5) increased risk for rapid renal function decline defined as a decline in eGFR ≥0.5 ml/min/1.73 m(2) per month. CONCLUSION: Nephrotic range proteinuria is the predominant renal risk factor in type 2 diabetic patients with severely impaired renal function receiving pre-dialysis care.

Prednisolone-glucose derivative conjugate: synthesis, biodistribution and pharmacodynamics evaluation.

This study was aimed at synthesizing and evaluating a prednisolone-glucose derivative conjugate (PDG) that was expected to increase renal biodistribution without affecting pharmacological action and to decrease the systemic side effects of prednisolone. The PDG was designed and synthesized by tethering 6-amino-6-deoxy-D-glucose (a D-glucose derivative) to prednisolone and its chemical structure was confirmed by (1) H NMR, (13) C NMR, and LC-MS. This conjugate was then subjected to in vitro and in vivo evaluation like stability studies, biological distribution, pharmacodynamics, and systemic side effects studies. In these studies, PDG not only showed significant enhancement of renal target efficiency with high values of relative uptake efficiency (RE, 24.1), concentration efficiency (CE, 8.6), and kidney targeting index (KTI, 16.3), but retained the curative potency against minimal change nephrosis (MCN). In the systemic side effects study, no osteoporosis was observed in rats after the administration of PDG for 20 days, which exhibited limited side effects. Conclusively, our findings showed a pharmacologically active conjugate with the characteristics of renal targeting and limited systemic side effects. The results implied the potential of PDG as a promising therapeutic in the treatment of renal diseases.

Dynamics of absolute amount of nephrin in a single podocyte in puromycin aminonucleoside nephrosis rats calculated by quantitative glomerular proteomics approach with selected reaction monitoring mode.

BACKGROUND: The slit diaphragm (SD) is a complex of podocyte-specific proteins and plays a significant role in glomerular filtration. To understand podocyte biology, it is important to determine the expression amount of the SD complex proteins. This study aimed to quantify the absolute amount of nephrin, which is believed to be a major component of SD, in podocytes and to apply that method to normal and puromycin aminonucleoside (PAN) nephrosis rats. METHODS: The counting method for podocyte number in a glomerulus was developed by three-dimensional reconstruction imaging of Wilms tumor (WT-1) immunofluorescence on isolated glomeruli. Absolute amount of nephrin was quantified by mass spectrometry using the selected reaction monitoring (SRM) mode with a stable isotope-labeled peptide. RESULTS: The number of podocytes per glomerulus was 95.5±17.6 in the control rats, 90.7±19.2 on Day 4 and 90.7±26.2 on Day 7 in PAN nephrosis rats. The amount of nephrin per glomerulus in control rats was 1.02±0.11 fmol and those in PAN nephrosis rats were reduced to 0.46±0.06 fmol and 0.35±0.04 fmol on Day 4 and Day 7. The nephrin amount per podocyte was significantly decreased association with the development of proteinuria in PAN nephrosis rats. CONCLUSIONS: This study established the absolute quantification of nephrin and determined the amount of nephrin in a podocyte of normal and PAN nephrosis rat kidneys. This highly sensitive and selective quantification method for protein is a useful tool for the analysis of SD protein in a podocyte.

Primary focal segmental glomerulosclerosis in nephrotic patients: common complications and risk factors.

BACKGROUND: Focal segmental glomerulosclerosis (FSGS) presents a range of potentially serious complications, including acute kidney injury (AKI), infection and thromboembolism. This study aimed to find out the incidence rates and risk factors for these complications in FSGS patients. METHODS: Patients with biopsy-proven primary FSGS and nephrotic-range proteinuria were included in this study. A short-term (16-week) follow-up was performed to observe the aforementioned complications. Clinical characteristics of patients were recorded upon enrollment. AKI was diagnosed as an absolute increase in serum creatinine of ≥0.3 mg/dL or a percentage increase of ≥50% within 48 hours; infection, by a combination of clinical manifestations, laboratory tests and imaging examinations; and thromboembolism, by imaging methods. Risk factors for complications were evaluated by logistic regression model. RESULTS: The study population included 90 FSGS patients (63 males, mean age 28.9 ± 12.9 years). The incidences of AKI, infection and thromboembolism were 44.4%, 25.6% and 12.2%, respectively. Patients with AKI were more likely to be male, with lower serum albumin, greater proteinuria and more severe acute tubulointerstitial damage. Patients with infection had higher proteinuria and lower serum albumin, globulin and IgG. Circulating endothelial cells (CECs) and von Willebrand factor were higher in patients with thromboembolism. Logistic regression showed that increased urine retinol-binding protein, decreased serum albumin and IgG, and increased CECs and hemoglobin were independent risk factors for AKI, infection and thromboembolism, respectively. CONCLUSIONS: AKI, infection and thromboembolism are common among FSGS patients. Awareness of risk factors and prevention of these complications are important for the prognosis of these patients.

Analysis of time course 1H NMR metabolomics data by multivariate curve resolution.

Modeling NMR-based metabolomics data often involves linear methods such as principal component analysis (PCA) and partial least squares (PLS). These methods have the objective of describing the main variance in the data and maximum covariance between the predictor variables and some response variable respectively. If the experiment is designed to investigate temporal biological fluctuations, however, the factors obtained become difficult to interpret in a biological context. Moreover, when these methods are applied to analyze data, an implicit assumption is made that the measurement errors exhibit an iid-normal distribution, often limiting the extent of the information recovered. A method for the linear decomposition of NMR-based metabolomics data by multivariate curve resolution (MCR), which has been used elsewhere for time course transcriptomics applications, is introduced and implemented via a weighted alternating least squares (ALS) approach. Measurement of error information is incorporated in the modeling process, allowing the least squares projections to be performed in a maximum likelihood fashion. As a result, noise heteroscedasticity resulting from pH-induced peak shifts can be modeled, eliminating the need for binning/bucketing. The utility of the method is demonstrated using two sets of temporal NMR metabolomics data, HgCl(2)-induced nephrotoxicity in rat, and fish (Japanese medaka, Oryzias latipes) embryogenesis. Profiles extracted for the nephrotoxicity data exhibit strong correlations with metabolites consistent with temporal fluctuations in glucosuria. The concentration of metabolites such as acetate, glucose, and alanine exhibit a steady increase, which peaks at Day 3 post dose and returns to basal levels at Day 8. Other metabolites including citrate and 2-oxoglutarate exhibit the opposite characteristics. Although the fish embryogenesis data are more complex, the profiles extracted by the algorithm display characteristics that depict temporal variation consistent with processes associated with embryogenesis.

Chronic kidney disease with three cases of oxalate-like nephrosis in Ragdoll cats.

Two unrelated Ragdoll cat mothers in Norway were found dead from renal disease. The histopathology was consistent with oxalate nephrosis with chronic or acute-on-chronic underlying kidney disease. Both cats had offspring and relatives with signs of urinary tract disease, including a kitten dead with urethral gravel. Eleven living Ragdoll cats, including nine relatives of the dead cats and the male father of a litter with similarly affected animals, were tested for primary hyperoxaluria (PH) type 1 and 2 by urine oxalate and liver enzyme analysis. Renal ultrasound revealed abnormalities in five living cats. One of these was azotaemic at the time of examination and developed terminal kidney disease 9 months later. A diagnosis of PH was excluded in 11 cats tested. The inheritance and aetiological background of the renal disease present in the breed remains unresolved at this point in time.

Plasmin in nephrotic urine activates the epithelial sodium channel.

Proteinuria and increased renal reabsorption of NaCl characterize the nephrotic syndrome. Here, we show that protein-rich urine from nephrotic rats and from patients with nephrotic syndrome activate the epithelial sodium channel (ENaC) in cultured M-1 mouse collecting duct cells and in Xenopus laevis oocytes heterologously expressing ENaC. The activation depended on urinary serine protease activity. We identified plasmin as a urinary serine protease by matrix-assisted laser desorption/ionization time of-flight mass spectrometry. Purified plasmin activated ENaC currents, and inhibitors of plasmin abolished urinary protease activity and the ability to activate ENaC. In nephrotic syndrome, tubular urokinase-type plasminogen activator likely converts filtered plasminogen to plasmin. Consistent with this, the combined application of urokinase-type plasminogen activator and plasminogen stimulated amiloride-sensitive transepithelial sodium transport in M-1 cells and increased amiloride-sensitive whole-cell currents in Xenopus laevis oocytes heterologously expressing ENaC. Activation of ENaC by plasmin involved cleavage and release of an inhibitory peptide from the ENaC gamma subunit ectodomain. These data suggest that a defective glomerular filtration barrier allows passage of proteolytic enzymes that have the ability to activate ENaC.

Conversion to sirolimus from cyclosporine may induce nephrotic proteinuria and progressive deterioration of renal function in chronic allograft nephropathy patients.

Antiproliferative and non-nephrotoxic properties of sirolimus have been exploited for treatment of patients with chronic graft dysfunction. In this paper we point to the possible association of nephrotic syndrome and renal impairment with rapid conversion from cyclosporine (CsA) to sirolimus in patients with chronic nephropathy. Five male patients, ages 34 to 56 years, with chronic renal failure in the course of glomerulonephritis, were transplanted between 1997 and 1999. For the first 49 to 65 months, the immunosuppressive regimen consisted of CsA, azathioprine (AZA), and prednisone. Thereafter, due to chronic nephropathy evidenced by biopsy, conversion to sirolimus was performed with sharp withdrawal of CsA. The serum creatinine level prior to conversion was 1.9 +/- 0.3 mg/dL. Trace to 86 mg/dL proteinuria was found in 3 patients, while 2 patients had about 200 mg/dL. After 2 to 4 months of sirolimus treatment the proteinuria progressed (558 +/- 183 mg/dL); edema, hypoproteinemia, hypoalbuminemia, and hyperlipidemia developed; and the serum creatinine increased to 3.5 +/- 0.8 mg/dL. Biopsies performed in three patients revealed new pathologic changes. After 4 to 5 months, we performed reconversion to calcineurin inhibitor. Proteinuria decreased to 0 to 150 mg/dL; nevertheless the serum creatinine was continuously rising. Six to 15 months after the conversion, 3 patients returned to dialysis. The fourth patient, who was earlier reconverted, has a serum creatinine level of 2.0 mg/dL after 15 months. In conclusion, conversion from CsA to sirolimus may induce nephrotic syndrome with progressive deterioration of renal function. Converted patients require careful monitoring of proteinuria and renal function. Early reconversion to calcineurin inhibitor may prevent progressive deterioration of graft function.

Effect of a novel free radical scavenger, edaravone, on puromycin aminonucleoside induced nephrosis in rats.

Recent studies indicate that excessive production of oxidants plays a role in the pathogenesis of glomerular injury leading to proteinuria in patients with minimal-change nephrotic syndrome (MCNS). The novel free radical scavenger, edaravone (EDA), which was recently developed in Japan, is currently used in patients with stroke. We studied whether this new agent would be beneficial in patients with MCNS by its antioxidant activity and examined its effect on proteinuria in nephrosis induced by puromycin-aminonucleoside (PAN) in rats. Nineteen Wistar-Kyoto rats injected with PAN were assigned to four groups: group 1, without EDA (n=4); group 2, concomitant EDA injection from 1 day prior to PAN administration (n=5); group 3, concomitant EDA injection from 1 day after PAN administration (n=5); group 4, concomitant EDA injection from 3 days after PAN administration (n=5). Daily urinary excretions of protein and 8-hydroxy-2'-deoxyguanosine (8-OHdG), a new sensitive marker of oxidative DNA damage in vivo, were measured in each group from the 1st to the 30th day after PAN injection. In group 1 proteinuria developed from the 5th day and reached the peak level on the 9th day. In groups 2, 3, and 4 proteinuria did not appear until the 6th day. The excretions in urinary protein and 8-OHdG were significantly lower in groups 2, 3, and 4 than group 1 on days 5, 9, and 25. In conclusion, EDA could delay and ameliorate the urinary protein excretion in accordance with the urinary 8-OHdG excretion in PAN-induced nephrosis.

A study of VEGF and its receptors in two rat models of proteinuria.

BACKGROUND: The high level of expression of vascular endothelial growth factor (VEGF) in normal podocyte foot processes suggests that VEGF has an important role in maintaining normal glomerular function. While altered VEGF expression occurs in many glomerular diseases, a direct role for VEGF in the pathogenesis of proteinuria has not been demonstrated. METHODS: Expression of VEGF and its receptors (VEGFR-1 and VEGFR-2) was examined in passive Heymann nephritis (PHN) and puromycin aminonucleoside nephrosis (PAN), by immunohistochemistry, in situ hybridization, Northern and Western blotting. Inhibition of VEGF in the PAN model was performed by administration of a blocking antibody. RESULTS: In both models, glomeruli showed upregulation of VEGF and VEGF receptors compared to control animals. VEGF mRNA was increased most significantly (5-fold) at day 5 after induction of PHN, prior to the onset of proteinuria, with persistent upregulation (3-fold) at day 21. Increased VEGF mRNA was also seen in PAN, but it was less marked. In situ hybridization and immunohistochemistry localized VEGF predominantly to podocytes. Increased expression of VEGFR-1 and VEGFR-2 protein was seen in glomerular endothelial cells of PHN and PAN rats by immunohistochemistry, as was VEGFR-2 mRNA by in situ hybridization. Upregulation of VEGFR-1 by endothelial cells was more striking in the PAN model than PHN. Administration of a blocking antibody to rats with PAN did not affect proteinuria, creatinine clearance or sodium excretion. CONCLUSION: The expression of VEGF and its receptors is significantly increased in the PHN and PAN rat models of proteinuria suggesting a role for VEGF in the disease process. VEGF may have an important role in promoting glomerular repair in a variety of glomerular diseases.

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.

Reduced 11beta-hydroxysteroid dehydrogenase activity in experimental nephrotic syndrome.

BACKGROUND: The disease state of the nephrotic syndrome is characterized by abnormal renal sodium retention that cannot be completely explained by a secondary hyperaldosteronism for the following reasons. Firstly, in rats an enhanced sodium retention is observed before proteinuria with intravascular volume depletion occurs. Secondly, in patients with the nephrotic syndrome, volume expansion with hypertension has been reported despite suppression of the renin-aldosterone system. Therefore, another mechanism for sodium retention must be postulated for this disease state. We hypothesize that this mechanism is a reduced 11beta-hydroxysteroid dehydrogenase 2 (11beta-HSD2) activity, a phenomenon known to cause enhanced access of cortisol or corticosterone to the mineralocorticoid receptor. METHODS: We assessed the 11beta-HSD activity by measuring the urinary ratio of tetrahydrocorticosterone (THB) plus 5alpha-tetrahydrocorticosterone (5alpha-THB) to 11-dehydro-tetrahydrocorticosterone (THA) by gas chromatography-mass spectrometry in rats with puromycin aminonucleoside (PAN)-induced proteinuria and with adriamycin nephrosis. Furthermore, the plasma ratios of corticosterone to 11-dehydrocorticosterone were measured. RESULTS: The urinary ratio of (THB+5alpha-THB)/THA increased in all animals following injection of PAN or adriamycin, indicating a reduced activity of 11beta-HSD. The reduced activity of 11beta-HSD was confirmed by an increased plasma ratio of corticosterone to 11-dehydrocorticosterone. The changes in the glucocorticoid metabolite ratios were already present before significant proteinuria appeared. CONCLUSION: PAN- or adriamycin-treated rats develop proteinuria with a reduced activity of 11beta-HSD, a mechanism contributing to the abnormal sodium retention in nephrotic syndrome.

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.