Urinary TGF-β1 Excretion Research Articles

НЕИНВАЗИВНЫЕ МАРКЕРЫ ФИБРОГЕНЕЗА У ДЕТЕЙ С ОСТРЫМ И ХРОНИЧЕСКИМ ВТОРИЧНЫМ ПИЕЛОНЕФРИТОМ

Objective of the study: to study the clinical significance of the determination of angiotensin 2 (Ang II) and transforming growth factor β1 (TGF-β1) in urine of children with acute and chronic secondary pyelonephritis (PN) for increasing the efficiency of diagnosis of the disease. Materials and methods of research: a prospective open non-randomized controlled longitudinal single-center study was carried out in the Speransky City Children’s Hospital № 9 from January 10, 2015 to June 2020 to study the sensitivity and specificity of the tests under study. 60 children from 1 to 15 years old with acute and chronic secondary PN were examined. Children were divided into 2 groups: 1st – 30 patients with the onset of acute PN, 2nd – 30 patients with recurrent chronic secondary PN. The control group consisted of 20 apparently healthy children. In the 1st group of patients, girls predominated (24 children, 80%), the median age was 7 [3; 9] years, the median duration of followup is 41 [8; 45] months from the onset of the disease. In the 2nd group girls also predominated – 23 (77%), the median age – 8 [5; 11] years, the median duration of the disease at the time of inclusion in the study was 5 [3; 9] years. Most children were diagnosed with vesicoureteral reflux (VUR): grade I–II – in 18 (60%) and grade II–III – in 7 (23%). Incomplete renal doubling was detected in 4 (14%) patients, complete – in one (3%). The control group mainly consisted of girls – 16 (80%), the median age – 5,5 [3,25; 8,75] years. All patients underwent a study of general clinical and biochemical blood test, general analysis of urine, determination in a single morning portion of urine by enzyme immunoassay method according to ELISA TGF-β1 and Ang II. To standardize the level of TGF-β1 and Ang II in the urine, the level of creatinine in each portion of urine was determined and the results were converted to 1 mg of creatinine. Instrumental examination included ultrasound of the kidneys and bladder before and after micturition. Static nephroscintigraphy was performed 6 months after the onset of the disease or recurrence of chronic secondary PN. Results: it was found that at the onset of acute PN and with relapses of chronic secondary PN, there was an increased urinary excretion of TGF-β1 (p=0,002) and Ang II (p=0,002) when compared with the control group. It was shown that the level of increase in these markers depended on the form of PN. There were statistically significant differences in the urinary excretion of TGF-β1 and Ang II in children with acute PN and exacerbation of chronic secondary PN prior to the initiation of antibiotic therapy (p=0,001 and p=0,001, respectively). Urinary levels of Ang II and TGF-β1 in patients with exacerbation of chronic secondary PN in the first days of the microbial-inflammatory process in the renal parenchyma were by an order of magnitude higher than those in children with the onset of acute PN. A high degree of correlation was revealed between the level of uAng II/Cr and uTGF-β1/Cr (r=0,75, p=0,0001 and r=0,89, p=0,0001, respectively) in the 1st and 2nd groups of children (r=0,86, p=0,0001 and r=0,75, p=0,001, respectively) in the acute phase of the disease before antibiotic therapy with the data obtained during static nephroscintigraphy in the period of remission of the disease. Conclusion: the results indicate the importance of studying the urinary excretion of Ang II/Cr and TGF-β1/Cr as additional diagnostic markers for the identification of patients with a relapse current of PN, as well as to predict the degree of development of sclerotic processes in the renal tissue in children with different forms of PN.

Investigation of the transforming growth factor-beta 1 signalling pathway as a possible link between hyperphosphataemia and renal fibrosis in feline chronic kidney disease

Chronic kidney disease (CKD) is common in geriatric cats, and is characterised in the majority of cases by tubulointerstitial inflammation and fibrosis. Hyperphosphataemia is a frequent complication of CKD and is independently associated with severity of renal fibrosis and disease progression. Transforming growth factor-beta 1 (TGF-β1) signalling is thought to be a convergent pathway which mediates the progression of renal fibrosis in CKD. The aims of this study were to explore the interaction between increased extracellular phosphate and the TGF-β1 signalling pathway by investigating: (a) the effect of a commercially available, phosphate-restricted, diet on urinary TGF-β1 excretion in cats with CKD; and (b) the role of increased extracellular phosphate in regulating proliferation, apoptosis, and expression of genes related to TGF-β1 signalling and extracellular matrix (ECM) production in feline proximal tubular epithelial cells (FPTEC) and cortical fibroblasts from cats with azotaemic CKD (CKD-FCF).The dietary intervention study revealed no effect of dietary phosphate restriction on urinary active TGF-β1 excretion after 4–8 weeks (P=0.98), despite significantly decreasing serum phosphate (P<0.001). There was no effect of increased growth media phosphate concentration (from 0.95mM to 2mM and 3.5mM) on proliferation (P=0.99) and apoptotic activity in FPTEC (P=0.22), or expression of genes related to ECM production and the TGF-β1 signalling pathway in FPTEC and CKD-FCF (P>0.05). These findings suggest the beneficial effects of dietary phosphate restriction on progression of feline CKD may not occur through modulation of renal TGF-β1 production, and do not support a direct pro-fibrotic effect of increased extracellular phosphate on feline renal cells.

P0305DIAGNOSTIC VALUE OF TGF-B-1 AND ANG II EXCRERION IN URINE IN CHILDREN WITH VESICOURETERAL REFLUX DEPENDING ON THE THERAPEUTIC APPROACH

Abstract Background and Aims to determine the diagnostic value of profibrogenic cytokines of transforming growth factor (TGF-β1) and angiotensin II (AngII) in urine to detect the severity of tubulointerstitial fibrosis in children with vesicoureteral reflux (VUR) depending on the therapeutic approach. Method 117 patients aged 3 to 16 years (mean age 10.2 ± 4.5, 70.1% of girls) with VUR were examined. The control group consisted of 20 healthy children. All children underwent a complete nephrological examination. The levels of TGF-β1 and AngII were determined in morning urine using the ELISA method and counted for urine creatinine. To identify the severity of the lesion of the renal parenchyma, a static DMSA scintigraphy was performed. Results depending on the therapeutic approach, the children were divided into 2 groups: 1 gr. - children on conservative treatment (63.2%), 2 gr. - children, after surgical correction of VUR (36.8%). In each group, 3 subgroups were identified depending on the development of tubulo-interstitial fibrosis according to DMSA: A subgr. - without signs of sclerosis (15.4%), B subgr. - 1-2 foci (44.74%) and C subgr - &amp;gt; 3-4 foci of sclerosis (40.1%). All patients with VUR had a high urinary excretion of TGF-β1/Cr and AngII/Cr when compared with the control group (p&amp;lt;0.05). Regardless of the therapeutic approach, in subgroups A (without foci of sclerosis) and B (1-2 foci of sclerosis), patients had a statistically significantly lower level of excretion of these cytokines when compared with patients from subgroup C (p &amp;lt;0.05). No significant difference was found in the urinary excretion of TGF-β1/Cr and AngII/Cr depending on the therapeutic approach. Conclusion we established a reliable dependence of the excretion of TGF-β1/Cr and AngII /Cr in the urine on the severity of tubulo-interstitial fibrosis according to DMSA scintigraphy in children with VUR. At the same time, we did not note the dependence of the excretion of TGF-β1/Cr and AngII/Cr in the urine on the method of the therapeutic approach. Therefore, the study of the excretion of TGF-β1/Cr and AngII/Cr in the urine as non-invasive markers can be used as a criterion for the progression of nephropathy in VUR, regardless of treatment methods.

Urinary Transforming Growth Factor β-1 as a Marker of Renal Dysfunction in Sickle Cell Disease

Sickle cell disease (SCD) is a genetic disorder that results in deformity of red blood cells. Renal dysfunction affects 5-18% of patients with SCD. To date, few studies have described urinary levels of transforming growth factor β-1 (TGF-β1), which is a marker of fibrosis, as a biomarker in identifying patients at risk of developing renal disease in SCD. The aim of this study is to determine prevalence of sickle cell nephropathy in Egyptian SCD patients. We aimed also to evaluate the association of urinary TGF-β1 with other conventional biomarkers of renal damage in SCD patients to identify a novel renal biomarker for early diagnosis of sickle nephropathy. We examined 40 SCD patients, 21 with sickle cell anemia, 16 sickle thalassemia, and three with sickle trait. We compared them to 20 control children with matched age and sex. The study was held in the time period between May 2013 and December 2013 in the Hematology Clinic, New Cairo University Children Hospital, Cairo, Egypt. Urinary excretion of TGF-β1 was 7.07±1.91ng/mL in SCD patients versus 2.23±0.76ng/mL in control children (p < 0.001). SCD patients had elevated estimated glomerular filtration rate (177.44±35.6mL/min/1.73m(2)), denoting a state of glomerular hyperfiltration. 47.5% of SCD patients had microalbuminuria. Urinary TGF-β1 correlated positively with microalbuminuria and estimated glomerular filtration rate (p=0.001 and p=0.018, respectively). We concluded that urinary TGF-β1 may serve as a marker of early renal injury in SCD.

Alport syndrome: the effects of spironolactone on proteinuria and urinary TGF-β1

Alport syndrome (AS) is a progressive hereditary glomerular disease. Recent data indicate that aldosterone promotes fibrosis mediated by the transforming growth factor-β1 (TGF-β1) pathway, which may worsen proteinuria. Spironolactone (SP) antagonizes aldosterone and this study aimed to evaluate the efficacy of SP in reducing proteinuria and urinary TGF-β1 excretion in proteinuric AS patients. The study involved ten children with AS, normal renal function, and persistent proteinuria (>6 months; uPr/uCr ratio >1). SP 25 mg once a day for 6 months was added to existing ACE inhibitor treatment with or without angiotensin-II receptor blockade. Urine and blood samples were examined monthly. Urinary TGF-β1 levels were measured twice before and three times during SP treatment. Plasma renin activity (PRA) and serum aldosterone levels were also measured. In eight patients, uProt/uCreat was also assessed after 9 months and 12 months of SP treatment. After beginning SP therapy, all patients showed significant decrease in mean uProt/uCreat ratio (1.77 ± 0.8 to 0.86 ± 0.6; p < 0.001) and mean urinary TGF-β1 levels (104 ± 54 to 41 ± 20 pg/mgCreatinine; p < 0.01), beginning after 30 days of treatment and remaining stable throughout SP administration. PRA remain unchanged, and mean serum aldosterone increased from 105 ± 72 pg/ml to 303 ± 156 pg/ml (p < 0.001). The only side effect was gynecomastia in an obese boy. After 1 year of therapy, mean uProt/uCreat remains low (0.82 ± 0.48). Addition of SP to ACE-I treatment with or without angiotensin II receptor blokers (ARB) significantly reduced proteinuria. This was mediated by decreased urinary TGF-β1 levels and not associated with major side effects.

Heterozygous knockout of transforming growth factor-β1 protects Dahl S rats against high salt-induced renal injury

The present study employed a zinc-finger nuclease strategy to create heterozygous knockout (KO) rats for the transforming growth factor-β1 (Tgfb1) gene on the Dahl SS/Jr genetic background (TGF-β1(+/-) Dahl S). Intercrossing TGF-β1(+/-) rats did not produce any homozygous KO rats (66.4% +/-, 33.6% +/+), indicating that the mutation is embryonic lethal. Six-week-old wild-type (WT) littermates and TGF-β1(+/-) Dahl S rats were fed a 0.4% (low salt, LS) or 8% NaCl (high salt, HS) diet for 5 wk. Renal cortical expression of TGF-β1, urinary TGF-β1 excretion, proteinuria, glomerular injury and tubulointerstitial fibrosis, and systolic blood pressure were similar in WT and TGF-β1(+/-) Dahl S rats maintained on the LS diet. The expression and urinary excretion of TGF-β1 increased to a greater extent in WT than in TGF-β1(+/-)Dahl S rats fed an HS diet for 1 wk. Systolic blood pressure rose by the same extent to 235 ± 2 mmHg in WT and 239 ± 4 mmHg in TGF-β1(+/-) Dahl S rats fed a HS diet for 5 wk. However, urinary protein excretion was significantly lower in TGF-β1(+/-) Dahl S than in the WT animals. The degree of glomerular injury and renal cortical and outer medullary fibrosis was markedly less in TGF-β1(+/-) than in WT rats. These findings suggest that the loss of one copy of the TGF-β1 gene blunts the increase in renal TGF-β1 protein expression and slows the progression of proteinuria, glomerulosclerosis, and renal interstitial fibrosis in Dahl S rats fed an HS diet independently of changes in blood pressure.

Abstract 6: Heterozygous TGFβ1 Zinc-Finger Knockout Dahl S Rats Reveal Protection Against High-Salt Induced Renal Injury

We used a zinc-finger nuclease strategy to create heterozygous TGFβ1 knockout rats (TGFβ1 +/- ) on a Dahl SS/Jr genetic background with a 22 base-pair frame shift mutation between nucleotides 191-212 which introduced a premature stop codon at amino acid 34. Intercrossing TGFβ1 +/- rats did not produce homozygous knockout rats, indicating that the mutation is embryonic lethal. Wildtype (WT) littermates and TGFβ1 +/- rats were fed either a 0.4% (normal salt, NS) or 8% NaCl (high salt, HS) diet for 5 weeks. When fed a NS diet, WT and TGFβ1 +/- exhibit similar renal cortical TGFβ1 expression (1.00±0.12 vs 1.05±0.05, arbitrary units), urinary TGFβ1 excretion (3.9±1.2 vs 5.3±0.4, μg/day), proteinuria (43±5 vs 36±4, mg/day), and minimal glomerular injury and tubulointerstitial fibrosis (TIF). 5 weeks of HS increased renal cortical TGFβ1 protein expression to a greater extent in WT versus TGFβ1 +/- (1.89±0.14 vs 1.52±0.09, arbitrary units) and TGFβ1 levels in urine increased to a greater extent in WT (41±10 μg/day) versus TGFβ1 +/- rats (18±4 μg/day) fed a HS diet for 1 week. Systolic blood pressure (SBP), measured by tail-cuff, was similar in WT (161±6 mmHg) and TGFβ1 +/- (162±7 mmHg) fed a NS diet and increased to the same extent in both WT (235±2 mmHg) and TGFβ1 +/- (239±4 mmHg) fed a HS diet for 5 weeks. Urinary protein excretion increased to a greater extent in WT versus TGFβ1 +/- (463±28 vs 313±36 mg/day) fed a HS diet for 5 weeks. Glomerular injury and renal cortical interstititial fibrosis were markedly reduced in TGFβ1 +/- versus WT after 5 weeks on a HS diet. Similarly, TIF in the renal medulla was less in TGFβ1 +/- compared with WT. These findings suggest that loss of one copy of the TGFβ1 gene blunts the increase in renal TGFβ1 protein in Dahl S rats fed a HS diet and slows the progression of proteinuria, glomerulosclerosis, and renal interstitial fibrosis independent of changes in blood pressure.

Importance and benefits of dietary sodium restriction in the management of chronic kidney disease patients: experience from a single Chinese center

Several studies have suggested that sodium intake may affect blood pressure (BP), proteinuria, and intrarenal transforming growth factor-β1 (TGF-β1) production in patients and animal models with chronic kidney disease (CKD). The Chinese population has a high prevalence of CKD and is well known for consuming salty foods. This study will investigate the role of dietary sodium intake on BP control among non-dialysis Chinese CKD patients. A cross-sectional study was carried out in a cohort of 176 non-dialysis hypertensive CKD patients to investigate their sodium intake and its effect on BP control by measuring 24-h urine sodium excretion (24-h UNa). A total of 20 patients with immunoglobulin A nephropathy (IgAN) participated in a 7-day sodium restriction study (100 mmol/day). Their changes in BP, proteinuria, and urinary TGF-β1 excretion were subsequently analyzed. Another 23 IgAN patients without salt restriction were included as controls. The average 24-h UNa of the study cohort was 149.0 ± 66.4 mmol/day. Only 31.8% patients had a 24-h UNa less than 100 mmol/day. The OR for each 17 mmol increment in 24-h UNa (salt 1 g/day) for BP > 130/80 mmHg was 1.26 (95% CI 1.10-1.44, P = 0.001). The sodium restriction group achieved significantly more reduction in SBP (-11.1 mmHg vs. -5.0 mmHg, P = 0.022), DBP (-9.4 mmHg vs. -2.1 mmHg, P = 0.009), and urine protein excretion [-465 (-855 to -340) mg/day vs. -150 (-570 to 40) mg/day, P = 0.024]. A positive correlation was observed between the change of 24-h UNa and the change of SBP (r = 0.450, P = 0.047) in the sodium restriction group. The change of 24-h UNa was also correlated with the 24-h TGF-β1 excretion (r = 0.558, P = 0.011) in these patients. Dietary sodium intake restriction should be monitored and intensified in the treatment of Chinese CKD patients.

Assessment of plasma and urinary transforming growth factor beta 1 (TGF-β1) in children with lupus nephritis

Background: Kidney disease is one of the most serious manifestations of systemic lupus erythematosus (SLE). Despite the improvement in the medical care of SLE in the past two decades, the prognosis of lupus nephritis remains unsatisfactory. Transforming growth factor- β1 (TGF-β1) is an immunosuppressive cytokine, as it inhibits T and B cell proliferation and NK cell cytotoxic activity . Objective: The aim of this study was to assess serum and urinary TGF- β1 levels in children with SLE and their possible role in the renal involvement and activity of the disease. Study design: This cross sectional study was conducted in Nephrology Unit of Pediatric Department, plus Outpatient Clinic of Rheumatology Department, Zagazig University Hospital during the year of 2010. Methods: Twenty-five pediatric patients with SLE were randomly selected and classified according to into 2 groups: Group (Ι): included 13 patients presented with urinary abnormalities and/or disturbed renal function(active nephritis): 5 males, 8 females. Their mean age was 9.7±2.53 years and the mean disease duration was 2.46±1.4 years. Group (ΙΙ): included 12 patients presented by lupus without nephritis : 5 males,7 females. Their mean age was 9.9±2.1 years and the mean disease duration was 2.41±0.9 years. Control group(group ΙΙΙ): Twenty healthy children of matched age and sex served as a control group included 8 males ,12 females. Their mean age was 10.0±2.3 years. Results: There was no significant difference among studied patients groups regarding age, sex , disease duration and lupus therapy (p>0.05). There was a significant difference between both groups regarding urinary albumin and serum creatinine (2.76±0.97 and 1.96±0.84 mg/dl respectively), while there was a high significant difference between them regarding C3 (47.3±12.5 and 76.6±6.6 mg/ml respectively) and anti double stranded DNA (anti-dsDNA) (80.7±32.8 and 26.8±4.5 IU/ml respectively). Plasma TGF- β1 showed significantly lower levels in patients with active nephritis relative to other groups, while urinary TGF- β1 levels were significantly high in SLE patients either with active or silent nephritis when compared with the control group. Plasma TGF- β1 showed a highly significant positive correlation with C3 and a highly significant negative correlation with serum creatinine, urinary albumin, anti dsDNA and SLE disease activity index (SLEDAI) score. While, urinary TGF- β1 had a significant negative correlation with C3 and a high significant positive correlation with anti-dsDNA and SLEDAI score. Conclusion: Low plasma TGF β1 level and increased urinary TGF β1 excretion denotes active renal affection in children with SLE. Keywords: SLE , nephritis , TGF- β1 Egypt J Pediatr Allergy Immunol 2011;9(1):21-27

Urinary transforming growth factor beta-1 as a marker of renal dysfunction in sickle cell disease

Renal dysfunction affects 5-18% of patients with sickle cell disease (SCD). To date, no studies have described urinary levels of transforming growth factor β-1 (TGF-β1), a marker of fibrosis, and neutrophil gelatinase-associated lipocalin (NGAL), a marker of acute/chronic kidney disease, as biomarkers in identifying patients at risk of developing renal disease in SCD. We hypothesized that SCD subjects will have increased urinary excretion of TGF-β1 and NGAL compared with healthy controls (CTR). We examined 51 SCD subjects: 42 HbSS, 8 HbSC, and 1 HbSD. Sixteen out of 42 patients with HbSS were on hydroxyurea (HU). Urinary excretion of TGF-β1 was 26.4 ± 1.5 pg/mgCr in SCD subjects vs 15.0 ± 2.4 pg/mgCr in CTR (p<0.00001). SCD patients with hemoglobin < 9 g/dl had higher urinary TGF-β1 than patients with milder anemia (p=0.002). Urinary TGF-β1 trended lower in HbSS patients treated with HU (23.61 ± 2.6 pg/mgCr), vs patients not on HU (27.69 ± 1.8 pg/mgCr; p=0.055). There was no correlation between urinary TGF-β1 and microalbuminuria or estimated glomerular function. There was no difference in urinary NGAL in SCD patients vs CTR. We suggest that urinary TGF-β1 may serve as a marker of early renal injury in SCD.

Non-Invasive Urinary Markers of Renal Dysfunction in Sickle Cell Disease.

Abstract 4621Renal failure is one of the major complications of sickle cell disease (SCD), affecting 5-18% of the patients. Microalbuminuria (MA), which has a prevalence of 26.5% in all children with SCD, is used as a marker of preclinical glomerular damage and renal disease progression. However, measuring MA alone may miss renal damage involving tubular proteins. We hypothesize that sickle cell nephropathy subjects will have increased urinary excretion of Transforming Growth Factor Beta-1 (TGF β1) and Neutrophil Gelatinase–Associated Lipocalin (NGAL) as compared to age-matched controls (CTR). We also hypothesize that urinary excretion of these proteins will be associated with severity of anemia in SCD. Enzyme-Linked Immunosorbent Assay (ELISA) kits were used to detect urinary excretion of TGF β1/NGAL, and corrected to urine creatinine. Mean age, gender, and race were not statistically different among the groups. Urinary excretion of TGF β1 was significantly higher in SCD subjects (26.4 pg/mg Cr +/-1.5) vs. CTR (14.9 pg/mg Cr +/-2.4), (p<0.00001). There was no difference in urinary NGAL between the SCD subjects vs. CTR. SCD patients with hemoglobin less than 9gm/dl had higher urinary TGF β1 than SCD patients with milder anemia (p=0.002). Urinary TGF β1 was lower in SCD patients on hydroxyurea (23.61+/-2.6), vs. those who were (27.69+/-1.8), p=0.08. Surprisingly, there were no correlation between urinary TGF β1 and urinary microalbumin or estimated glomerular function, indicating that microalbuminuria and serum creatinine are poor measures of renal injury in SCD patients.Our data suggests that urinary TGF β1 may serve as a urinary biomarker to monitor the progression of renal disease in SCD. This assumption needs to be tested prospectively. Disclosures:No relevant conflicts of interest to declare.

Antifibrotic Effects of Aldosterone Receptor Blocker (Spironolactone) in Patients with Chronic Kidney Disease

Aims. Proteinuria and transforming growth factor β (TGF-β) are parameters that can lead to glomerulosclerosis and tubulointerstitial fibrosis. All components of the renin-angiotensin-aldosterone system (RAAS) activate the TGF-β. Aldosterone may not be inhibited with angiotensin-converting enzyme inhibitors (ACEIs) and/or angiotensin receptor blockers (ARBs) due to aldosterone escape. We aimed to evaluate the effect of spironolactone on parameters leading to fibrosis. Methods. This prospective study included 30 non-diabetic chronic kidney disease (CKD) patients treated with ACEIs and/or ARBs. The patients were divided into two groups that are similar in terms of demographic parameters. 25 mg of spironolactone was added to group 1 (n = 15) for six months, though it was not administered to group 2 (n = 15). Creatinine (U-Cr), protein (U-Prot), and TGF-β1 (U- TGF-β1) were measured in spot urine sample in the beginning of study and six months later. Results. Twenty-four patients completed the study. There were no significant changes in mean blood pressure, glomerular filtration rate, creatinine, albumin, and plasma aldosterone concentrations during the observation period in either group. U-Prot/U-Cr (mg/mg Cr) was reduced from 2.43 ± 4.85 at baseline to 1.66 ± 3.51 at sixth month (p = 0.003) in group 1. In addition, U-TGF-β1/U-Cr (ng/mg Cr) was also reduced from 22.50 ± 6.65 at baseline to 17.78 ± 10.94 at sixth month (p = 0.041) in the same group. U-TGF-β1/U-Cr and U-Prot/U-Cr ratios after the sixth month were not found significant compared with baseline values in group 2. Conclusion. Spironolactone reduced both proteinuria and urinary TGF-β1 excretion in CKD patients. We consider that spironolactone would be beneficial to prevent progression of renal fibrosis in CKD.

Effect of low-dose dual blockade of renin–angiotensin system on urinary TGF-β in type 2 diabetic patients with advanced kidney disease

We evaluated the renoprotective effects of dual blockade of renin-angiotensin system (RAS) by using a low-dose combination of ACE inhibiter and angiotensin II receptor blocker in type 2 diabetic patients with advanced kidney disease. The amount of proteinuria and the urinary levels of bioassayable TGF-beta1 were used as surrogate markers of renal injury and sclerosis. We performed a prospective double-blinded randomized crossover trial consisting of three 16-week treatment periods with ramipril alone (10 mg/day), candesartan alone (16 mg/day), and ramipril (5 mg/day) plus candesartan (8 mg/day) combination therapy. Twenty-one type 2 diabetic patients with overt nephropathy with a 24 h urinary protein excretion rate (UPER) of > 1.0 g/24 h and creatinine clearance (Ccr) of 30 to 59 ml/min/1.73 m2 completed the entire study. Subjects consisted of 10 female and 11 male patients with a mean age of 49 +/- 8 years and duration of diabetes ranging from 4 to 13 years. At baseline, 24-h blood pressures (BPs) were 133 +/- 6/81 +/- 7 mmHg, Ccr 40.6 +/- 4.1 ml/min/1.73 m2, 24-h UPER 4.1 +/- 1.9 g/24 h, and urinary TGF-beta1 level 28.4 +/- 16.1 pg/mg creatinine (cr). Although there was no comparable change in BP and plasma/urinary biochemical parameters, 24-h UPER was significantly reduced by the combination therapy (2.9 +/- 1.4 g/24 h) compared with that of ramipril (3.5 +/- 1.8 g/24 h) and of candesartan (3.3 +/- 2.0 g/24 h) single therapy (P < 0.05). Urinary TGF-beta1 level was reduced in all three therapies compared with that of the control (28.4 +/- 16.1 pg/mg cr) (P < 0.05). However, the combination therapy showed the most significant change (combination 19.6 +/- 10.6 pg/mg cr; ramipril 24.7 +/- 13.3 pg/mg cr; candesartan; 23.4 +/- 11.7 pg/mg cr). No significant or irreversible adverse effect was observed in the 21 patients who completed the entire study. The dual blockade of RAS with low-dose ramipril plus candesartan was found to be safe and offered additive benefits with respect to reducing proteinuria and urinary TGF-beta1 excretion in diabetic patients with advanced kidney disease. These benefits were evident as compared with single ramipril and candesartan therapies at doses two-fold greater. Further study on the dose-titration is mandatory in terms of safety and especially for maximizing renoprotection in this patient population.

Urinary transforming growth factor-β1 in various types of nephropathy

Transforming growth factor-β1 (TGF-β1) is a potent multifunctional polypeptide that is involved in normal renal function and in the development of glomerular sclerosis. It is also an important mediator of the immune and anti-inflammatory responses. The purpose of this study was to examine whether the measurement of urinary TGF-β1 excretion in patients with different types of renal diseases and in newly diagnosed type 1 diabetes mellitus represents a non-invasive tool to evaluate disease activity and to monitor response to therapy. We studied the urinary excretion of TGF-β1 in 57 nephropathic patients divided in different groups according to the underlying disease: 15 had mesangial glomerulonephritis (IgAGN), 9 membranous glomerulonephritis (MGN), 7 rapidly progressive glomerulonephritis (RPGN), 8 systemic lupus erythematosus (SLE), 9 interstitial nephritis (IN), 9 chronic renal failure (CRF). TGF-β1 was also measured in 38 patients with type 1 (insulin-dependent) diabetes mellitus (12 with newly diagnosed diabetes, 26 long-standing diabetes) and 31 healthy controls. Total urinary TGF-β1 concentration was assayed by enzyme-linked immunoassay (ELISA), and expressed as a ratio to urinary creatinine concentration. The urinary TGF-β1 levels were compared with the findings of biopsy and clinical parameters. Urinary TGF-β1 excretion was significantly increased in all groups except MGN, IN and CRF. In non-diabetic patients, urinary TGF-β1 levels correlated with crescent formation, floccular adhesion and mesangial proliferation, but not with the degree of tubulo-interstitial fibrosis. Urinary TGF-β1 levels did not correlate with indices of renal function (serum creatinine, glomerular filtration rate (GFR), albumin excretion rate [AER]). Among diabetic patients, HbA 1C significantly correlated with TGF-β1 urinary excretion. Urinary TGF-β1 levels may represent a valid indicator of acute glomerular flogosis associated with mesangial proliferation in glomerulonephrities. In newly diagnosed diabetic patients, hyperglycaemia seems to represent the principal factor leading to TGF-β1 overproduction. Follow-up studies of urinary TGF-β1 levels measured during optimal glycaemic control are necessary to clarify the relationship between hyperglycaemia and TGF-β1 excretion.

Urinary Transforming Growth Factor-β1 Excretion in Renal Allograft Recipients During the Early Post-transplantation Period

Background. Transforming growth factor-β1 (TGF-β1), the major fibrogenic growth factor, is implicated in the pathogenesis of renal scarring in experimental and clinical nephropathies as well as in chronic allograft nephropathy. In this study we examined the pattern of changes of TGF-β1 excretion in the urine and the sites of TGF-β1 expression in the kidney of transplanted patients during the early post-transplantation period. Methods. Eighteen renal allograft recipients were included in the study. In all patients urinary TGF-β1 levels were determined by ELISA in sequential measurements during the first two postoperative months and compared to that of 14 healthy subjects. The renal expression of TGF-β1 protein was studied in 4 patients that underwent a biopsy of the transplanted kidney at the same period. All patients were treated with prednisolone, cyclosporin, and mycophenolate mofetil. Results. Urinary TGF-β1 levels were increased during the first postoperative days. Although they were gradually reduced during the first two post-operative months, they remained significantly higher compared to those of normal subjects (580 ± 148 ng/24 h vs. 310 ± 140 ng/24 h p<0.01). The decline of urinary TGF-β1 excretion followed that of serum creatinine. TGF-β1 protein expression was identified within the cytoplasm of tubular epithelial cells of transplanted patients. Conclusions. Elevated urinary TGF-β1 levels are observed during the early post-transplantation period in renal allograft recipients and are maintained high even after restoration of renal function to normal.

Steroid therapy and urinary transforming growth factor-β1 in IgA nephropathy

Transforming growth factor-β1 (TGF-β1) has an important role in the pathogenesis of glomerular damage by influencing matrix metabolism. An association of TGF-β1 with glomerulosclerosis and interstitial fibrosis has been shown in various renal diseases, suggesting that TGF-β1 may serve as a diagnostic marker of glomerular diseases. The aim of this study is to determine the usefulness of urinary TGF-β1 values to monitor therapeutic effects of steroids in patients with immunoglobulin A (IgA) nephropathy. Concentrations and activation rates of TGF-β1 (mature/total) were determined in urine of patients with renal diseases by means of a double-antibody enzyme immunoassay. The urinary TGF-β1 level before steroid therapy was compared with renal histological characteristics, creatinine clearance, and proteinuria in patients with a variety of renal diseases. Urinary excretion of total and mature TGF-β1 was significantly greater in patients with crescentic glomerulonephritis and IgA nephropathy than in healthy controls, whereas the activation rate of urinary TGF-β1 was similar among patients with other renal diseases. Urinary TGF-β1 excretion at the time of renal biopsy significantly correlated with the degree of crescent formation in patients with IgA nephropathy, but not in those with glomerular sclerosis or tubulointerstitial fibrosis. Urinary excretion of total and mature TGF-β1 was reduced in patients with IgA nephropathy after treatment with prednisolone (0.8 mg/kg/d) for 1 month. The activation rate of urinary TGF-β1 also decreased significantly after steroid therapy. Urinary TGF-β1 values therefore may be useful to assess disease activity or the effects of steroid therapy in patients with IgA nephropathy. © 2001 by the National Kidney Foundation, Inc.

Increased Excretion of Urinary Transforming Growth Factor Beta 1 in Patients with Diabetic Nephropathy

The accumulation of extracellular matrix in the glomeruli of human and experimental models of diabetic nephropathy is associated with disease progression. Transforming growth factor beta 1 (TGF-β1), which is a multifunctional peptide growth factor, plays a key role in the synthesis of extracellular matrix protein in vitro, and the expression of TGF-β1 is elevated in human and rat diabetic nephropathy. In this study, we measured the urinary TGF-β1 excretion in 57 patients with non-insulin-dependent diabetes mellitus and in 20 healthy volunteers to examine whether the determination of urinary TGF-β1 excretion would facilitate the evaluation of the degree of mesangial expansion in patients with diabetic nephropathy. Both active and total TGF-β1 levels in 24-hour urine samples collected from patients with diabetes mellitus and normal controls were measured using an enzyme-linked immunosorbent assay. We observed a higher excretion of urinary TGF-β1 in patients with diabetes mellitus than in normal controls. In addition, the urinary TGF-β1 excretion was elevated in patients with severe mesangial expansion. These results suggest that urinary TGF-β1 may represent one parameter that can be used to evaluate the progression of diabetic nephropathy.

Dietary salt modulates renal production of transforming growth factor-β in rats

Transforming growth factors (TGF) are potent multifunctional polypeptides that are involved in renal function and glomerular sclerosis. We postulated that dietary salt modified renal production of TGF-beta. An increase in dietary salt produced sustained increases in steady-state levels of mRNA for TGF-beta 1, -beta 2, and -beta 3 in the rat kidney. While serum concentration of TGF-beta 1 did not change, the 8.0% NaCl diet increased urinary excretion of TGF-beta 1, indicating enhanced renal production was the source of TGF-beta 1. Increasing urinary flow rates with diuretics did not further increase synthesis of TGF-beta 1 in animals receiving the 8.0% NaCl diet. The 8.0% NaCl diet increased production of TGF-beta 1 in both glomeruli and tubules, although active TGF-beta 1 was secreted in greater amounts only from glomeruli. Enhanced glomerular production of both inactive and active TGF-beta 1 induced by the 8.0% NaCl diet was inhibited by tetraethylammonium (TEA) and not glybenclamide. Cardiac production of TGF-beta 1 also increased on the 8.0% NaCl diet but was not affected by TEA. The results demonstrated that increased dietary salt augmented glomerular TGF-beta production by a mechanism that included a TEA-sensitive potassium channel. Dietary salt, by facilitating glomerular expression of TGF-beta, may directly promote development of glomerulosclerosis.