Augmented transcripts of kidney injury markers and renin angiotensin system in urine samples of overweight young adults.

Obesity has been firmly established as a major risk factor for common disease states including hypertension, type 2 diabetes mellitus, and chronic kidney disease. Increased body mass index (BMI) contributes to the activation of both the systemic and intra-tubular renin angiotensin systems (RAS), which are in turn associated with increased blood pressure (BP) and kidney damage. In this cross-sectional study, 43 subjects of normal or increased body weight were examined in order to determine the correlation of BMI or body fat mass (BFM) with blood pressure, fasting blood glucose (FBG), and urinary kidney injury markers such as interleukin-18 (IL-18), connective tissue growth factor (CTGF), neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1 (KIM-1). Our results showed that: (1) subjects with increased body weight showed significantly higher BP, BFM, total body water and metabolic age; (2) BMI was positively correlated to both systolic (R2 = 0.1384, P = 0.01) and diastolic BP (R2 = 0.2437, P = 0.0008); (3) BFM was positively correlated to DBP (R2 = 0.1232, P = 0.02) and partially correlated to urine protein (R2 = 0.047, P = 0.12) and FBG (R2 = 0.07, P = 0.06); (4) overweight young adults had higher urinary mRNA levels of renin, angiotensinogen, IL-18 and CTGF. These suggest that BMI directly affects BP, kidney injury markers, and the activation of the intra-tubular RAS even in normotensive young adults. Given that BMI measurements and urine analyses are non-invasive, our findings may pave the way to developing a new and simple method of screening for the risk of chronic kidney disease in adults.

Is there any relation between connective tissue growth factor and scar tissue in vesicoureteral reflux?

Gültekin ND, Benzer M, Tekin-Neijmann S. Is there any relation between connective tissue growth factor and scar tissue in vesicoureteral reflux. Turk J Pediatr 2019; 61: 71-78. Vesicoureteral reflux (VUR) is the most common uropathy in childhood which leads to increased frequency of urinary tract infection (UTI) and renal scarring. Connective tissue growth factor (CTGF) plays an important role in the development of glomerular and tubulointerstitial fibrosis in progressive kidney diseases. The aim of this study was to investigate the relation between urinary CTGF and renal damage resulted from VUR. This cross sectional study included 70 patients with VUR and 62 healthy sex and age matched children. Urinary creatinine and CTGF (uCTGF) concentrations were analysed in all cases and CTGF to creatinine ratio were calculated. The records of radiologic evaluations of the patients including ultrasound, voiding cystouretrography and 99m-technetium dimercaptosuccinic acid (DMSA) scintigraphy were obtained retrospectively. The patient group was further divided into two groups according to the existence of renal cortical scarring in the DMSA scan. The study consisted of three groups; Group 1 (control group) 62 children, Group 2 (VUR positive, scar negative) 24 patient, Group 3 (VUR positive, scar positive) 46 patient (VUR+scar). The medians of uCTGF and uCTGF to creatinine ratio of the three groups were significantly different (p < 0.001). Pairwise group comparisons revealed that Group 1 had significantly lower uCTGF level and uCTGF/creatinine ratio, as compared to Groups 2 and 3 (p < 0.001 and p=0.002, respectively). There was no statistically significant difference between Groups 2 and 3 (p=0.052). uCTGF is significantly increased in children with VUR, independent on the presence of renal scarring. Increased uCTGF, even in the absence of the renal scarring, could be interpreted as development and a progression of glomerular and tubulointerstitial fibrosis in vesicoureteral reflux. Further experimental and clinical investigations are required to fully elucidate the mechanism of CTGF in vesicoureteral reflux.

Functionalized aptamer with an antiparallel G-quadruplex: Structural remodeling, recognition mechanism, and diagnostic applications targeting CTGF.

Connective tissue growth factor (CTGF), a widely used biomarker, is involved in many diseases, such as diabetic retinopathy, diabetic nephropathy, and rheumatoid arthritis, and it is often over-expressed in human malignant tumors. Therefore, sensitive, specific and efficient detection methods for CTGF are needed for the early diagnosis and assessment of prognosis. In this study, an aptamer, APT1, that specifically binds to CTGF was obtained by SELEX technology. Circular dichroism spectroscopy indicated that APT1 formed interconvertible parallel and antiparallel G-quadruplexes. Mutation and truncation strategies optimized APT1 and improved its functions, yielding APT1M6T, which folded into an antiparallel G-quadruplex with higher targeting affinity. A stable APT1M6T-CTGF complex model was established by molecular simulation, which helped elucidate the molecular recognition mechanism of APT1M6T and CTGF and also provided experimental guidance for rational site-directed modification of APT1M6T. A locked nucleic acid sequence was then integrated into APT1M6T to generate APT1M6TL, which had higher structural stability. A BLI-based enzyme-linked aptamer sandwich assay (BLI-ELASA) was successfully developed. The method exhibited a broad detection range from 0.05 to 50 nM with a low detection limit of 0.02 nM. The method showed high selectivity, reproducibility, and stability for analysis of CTGF in spiked serum and urine samples. This developed BLI-ELASA is promising and enables real-time, sensitive and rapid detection of the disease-specific biomarker CTGF.

Tubulointerstitial expression and urinary excretion of connective tissue growth factor 3 months after renal transplantation predict interstitial fibrosis and tubular atrophy at 5 years in a retrospective cohort analysis.

Connective tissue growth factor (CTGF) is an important mediator of renal allograft fibrosis, and urinary CTGF (CTGFu) levels correlate with the development of human allograft interstitial fibrosis. We evaluated the predictive value of CTGF protein expression in 160 kidney transplant recipients with paired protocol biopsies at 3 months and 5 years after transplantation. At month 3 and year 1, CTGFu was measured using ELISA, and biopsies were immunohistochemically stained for CTGF, with semiquantitative scoring of tubulointerstitial CTGF-positive area (CTGFti). Predictors of interstitial fibrosis and tubular atrophy (IF/TA) severity at 5 years were donor age [OR 1.05 (1.02-1.08), P = 0.001], female donor [OR 0.40 (0.18-0.90), P = 0.026], induction therapy [OR 2.76 (1.10-6.89), P = 0.030], and CTGFti >10% at month 3 [OR 2.72 (1.20-6.15), P = 0.016]. In subgroups of patients with little histologic damage at 3 months [either ci score 0 (n = 119), IF/TA score ≤1 (n = 123), or absence of IF/TA, interstitial inflammation, and tubulitis (n = 45)], consistent predictors of progression of chronic histologic damage by 5 years were donor age, induction therapy, CTGFti >10%, and CTGFu. These results suggest that, even in patients with favorable histology at 3 months, significant CTGF expression is often present which may predict accelerated accumulation of histologic damage.

New frontiers in fibrotic disease therapies: The focus of the Joan and Joel Rosenbloom Center for Fibrotic Diseases at Thomas Jefferson University.

Fibrotic diseases constitute a world-wide major health problem, but research support remains inadequate in comparison to the need. Although considerable understanding of the pathogenesis of fibrotic reactions has been attained, no completely effective therapies exist. Although fibrotic disorders are diverse, it is universally appreciated that a particular cell type with unique characteristics, the myofibroblast, is responsible for replacement of functioning tissue with non-functional scar tissue. Understanding the cellular and molecular mechanisms responsible for the creation of myofibroblasts and their activities is central to the development of therapies. Critical signaling cascades, initiated primarily by TGF-ß, but also involving other cytokines which stimulate pro-fibrotic reactions in the myofibroblast, offer potential therapeutic targets. However, because of the multiplicity and complex interactions of these signaling pathways, it is very unlikely that any single drug will be successful in modifying a major fibrotic disease. Therefore, we have chosen to examine the effectiveness of administration of several drug combinations in a mouse pneumoconiosis model. Such treatment proved to be effective. Because fibrotic diseases that tend to be chronic, are difficult to monitor, and are patient variable, implementation of clinical trials is difficult and expensive. Therefore, we have made efforts to identify and validate non-invasive biomarkers found in urine and blood. We describe the potential utility of five such markers: (i) the EDA form of fibronectin (Fn(EDA)), (ii) lysyl oxidase (LOX), (iii) lysyl oxidase-like protein 2 (LoxL2), (iv) connective tissue growth factor (CTGF, CCNII), and (v) the N-terminal propeptide of type III procollagen (PIIINP).

Elevated Urinary Connective Tissue Growth Factor in Diabetic Nephropathy Is Caused by Local Production and Tubular Dysfunction.

Connective tissue growth factor (CTGF; CCN2) plays a role in the development of diabetic nephropathy (DN). Urinary CTGF (uCTGF) is elevated in DN patients and has been proposed as a biomarker for disease progression, but it is unknown which pathophysiological factors contribute to elevated uCTGF. We studied renal handling of CTGF by infusion of recombinant CTGF in diabetic mice. In addition, uCTGF was measured in type 1 DN patients and compared with glomerular and tubular dysfunction and damage markers. In diabetic mice, uCTGF was increased and fractional excretion (FE) of recombinant CTGF was substantially elevated indicating reduced tubular reabsorption. FE of recombinant CTGF correlated with excretion of endogenous CTGF. CTGF mRNA was mainly localized in glomeruli and medullary tubules. Comparison of FE of endogenous and recombinant CTGF indicated that 60% of uCTGF had a direct renal source, while 40% originated from plasma CTGF. In DN patients, uCTGF was independently associated with markers of proximal and distal tubular dysfunction and damage. In conclusion, uCTGF in DN is elevated as a result of both increased local production and reduced reabsorption due to tubular dysfunction. We submit that uCTGF is a biomarker reflecting both glomerular and tubulointerstitial hallmarks of diabetic kidney disease.

Connective tissue growth factor and the cicatrization of cellular crescents in ANCA-associated glomerulonephritis.

BACKGROUND: Outcome in patients with anti-neutrophil cytoplasmic antibodies (ANCA)-associated glomerulonephritis (AGN) is difficult to predict. Scoring of renal biopsies has significant but limited predictive value. We investigated whether analysis of plasma and urine levels, and immunostaining of biopsies for the pro-fibrotic peptide connective tissue growth factor (CTGF), might improve prediction of renal outcome. METHODS: ANCA-positive patients were included. Renal biopsies were classified according to the AGN classification. Biopsies were stained for CTGF protein. CTGF was measured by ELISA at the time of renal biopsy in plasma and urine, and during follow-up in plasma. RESULTS: Eighty-two patients were included. CTGF staining was positive in crescentic lesions. Plasma CTGF at the time of renal biopsy was 2.4 ± 1.7 pmol/mL when compared with 0.5 ± 0.0 pmol/mL in healthy controls (P < 0.01). Plasma CTGF was associated with cellular crescents, but not when corrected for renal function. Plasma CTGF at baseline was associated with fibrous crescents in the follow-up biopsy, also after correction for renal function. Plasma CTGF at baseline predicted renal survival more accurately than the AGN classification. CONCLUSION: In AGN patients, CTGF was overexpressed in crescentic glomeruli. Baseline plasma CTGF predicted the percentage of fibrous crescents in later biopsies, and renal survival, suggesting that CTGF is involved in the cicatrization, as opposed to resolution of cellular crescents in AGN.

Protective effect of statin therapy on connective tissue growth factor induction by diabetes in vivo and high glucose in vitro.

Transcriptional activity of connective tissue growth factor (CTGF) promoter in transfected HEK293 cells was determined by luciferase assays. Secreted CTGF in cultured human mesangial cells was measured by enzyme-linked immunosorbent assay (ELISA). CTGF in urine and plasma was also measured in 405 subjects with/without type 2 diabetes. Our results showed that high glucose significantly increased transcription of the promoter in the transfected cells by more than 2.5-folds (p < 0.0005). CTGF secretion was induced by high glucose in the cells (p < 0.0005). These increases were inhibited by simvastatin. Urine CTGF was positively associated with plasma CTGF in both type 2 diabetes (p = 0.0005) and controls (p = 0.01). Urine CTGF levels in patients with macroalbuminuria were significantly higher than patients without macroalbuminuria (p < 0.05). In conclusion, our in vitro study suggests that statin may have a renal-protective effect through the inhibition of CTGF expression. Urine CTGF may be a good marker for the prediction of diabetic nephropathy.

Urinary connective tissue growth factor is associated with human renal allograft fibrogenesis.

BACKGROUND: Connective tissue growth factor (CTGF) is a key mediator of tissue fibrogenesis in kidney disease. Its involvement in renal allograft fibrosis was recently demonstrated in a mouse model. METHODS: We prospectively studied the association between urinary CTGF (CTGFu) levels and renal allograft fibrosis during the first 2 years after transplantation. Histologic and biochemical data were collected from 315 kidney transplant recipients enrolled in a protocol biopsy-based clinical program. RESULTS: At 3, 12, and 24 months after transplantation, CTGFu levels were independently associated with the degree of interstitial fibrosis in protocol biopsies, scored according to the revised 1997 Banff criteria. In a subgroup of 164 patients with pristine biopsies at 3 months, higher CTGFu levels at 3 months were associated with moderate and severe interstitial fibrosis developed at 24 months after transplantation. CONCLUSIONS: As it is readily quantifiable in urine, a role for CTGFu as a noninvasive candidate biomarker and predictor of human renal allograft fibrogenesis deserves further study.

Effect of loganin on experimental diabetic nephropathy.

Connective tissue growth factor (CTGF) plays a pathogenic role in diabetic nephropathy (DN). Loganin, an iridoid glucoside compound was isolated from Cornus officinalis Sieb. et Zucc. This study was conducted to investigate the efficacy of loganin on DN and to elucidate the potential mechanism. High glucose (HG) stimulated cultured human renal proximal tubular epithelial cells (HK-2) analyzed CTGF expression by Western blotting and investigated whether extracellular signal-regulated kinase (ERK) signaling pathway was involved. Streptozotocin (STZ)-induced experimental DN, randomized to receive intragastric (i.g.) of loganin. Renal tissue, blood and urine samples were collected to determine and analyze. In vitro study, loganin reduced CTGF excretion in HG-induced HK-2 cells through the ERK signaling pathway. In vivo study, I.g. of loganin 5 mg/kg or 10 mg/kg significantly ameliorated renal function and increased body weight. Meanwhile, loganin reduced renal CTGF expression by immunohistochemical staining, reduced serum levels of CTGF. Besides, there were no significant differences in blood sugar levels between the loganin groups compared to the STZ-treated group. Furthermore, loganin ameliorated renal pathology. These results suggested that loganin exerts an early renal protective role to DN. Inhibition of CTGF may be a potential target in DN therapy, which highlights the possibility of using loganin to treat DN.

Effects of antiproteinuric intervention on elevated connective tissue growth factor (CTGF/CCN-2) plasma and urine levels in nondiabetic nephropathy.

BACKGROUND AND OBJECTIVES: Connective tissue growth factor (CTGF/CCN-2) is a key player in fibrosis. Plasma CTGF levels predict end-stage renal disease and mortality in diabetic chronic kidney disease (CKD), supporting roles in intra- and extrarenal fibrosis. Few data are available on CTGF in nondiabetic CKD. We investigated CTGF levels and effects of antiproteinuric interventions in nondiabetic proteinuric CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: In a crossover randomized controlled trial, 33 nondiabetic CKD patients (3.2 [2.5 to 4.0] g/24 h proteinuria) were treated during 6-week periods with placebo, ARB (100 mg/d losartan), and ARB plus diuretics (100 mg/d losartan plus 25 mg/d hydrochlorothiazide) combined with consecutively regular and low sodium diets (193 ± 62 versus 93 ± 52 mmol Na(+)/d). RESULTS: CTGF was elevated in plasma (464 [387 to 556] pmol/L) and urine (205 [135 to 311] pmol/24 h) of patients compared with healthy controls (n = 21; 96 [86 to 108] pmol/L and 73 [55 to 98] pmol/24 h). Urinary CTGF was lowered by antiproteinuric intervention, in proportion to the reduction of proteinuria, with normalization during triple therapy (CTGF 99 [67 to 146] in CKD versus 73 [55 to 98] pmol/24 h in controls). In contrast, plasma CTGF was not affected. CONCLUSIONS: Urinary and plasma CTGF are elevated in nondiabetic CKD. Only urinary CTGF is normalized by antiproteinuric intervention, consistent with amelioration of tubular dysfunction. The lack of effect on plasma CTGF suggests that its driving force might be independent of proteinuria and that short-term antiproteinuric interventions are not sufficient to correct the systemic profibrotic state in CKD.

Lower urinary connective tissue growth factor levels and incident CKD stage 3 in the general population.

BACKGROUND: Connective tissue growth factor (CTGF) is involved in the development and progression of kidney diseases, including diabetic nephropathy and kidney fibrosis, but also may have a role in mesangial repair after injury. It is unknown whether, in the general population, urinary CTGF levels are associated with a decrease in estimated glomerular filtration rate (eGFR) to <60 mL/min/1.73 m(2) (ie, development of chronic kidney disease [CKD] stage 3). STUDY DESIGN: Nested case-control. SETTING & PARTICIPANTS: 100 cases of incident CKD stage 3 and 100 age-and sex-matched controls in the Framingham Heart Study; 141 cases and 135 age-, sex-, and race-matched controls in the Atherosclerosis Risk in Communities (ARIC) Study. Controls had eGFR ≥60 mL/min/1.73 m(2) at follow-up in both studies. PREDICTORS: Urinary CTGF concentrations. OUTCOMES: Incident CKD stage 3, defined as eGFR <60 mL/min/1.73 m(2). MEASUREMENTS: Stored urine samples from Framingham Heart Study and ARIC were measured for CTGF. Covariates were obtained from Framingham Heart Study and ARIC participant examinations. RESULTS: In the Framingham Heart Study, the median baseline urinary CTGF concentration was lower in cases (1.35 ng/mL) than controls (2.35 ng/mL; paired t test, P < 0.0001). The multivariable-adjusted OR for incident CKD stage 3 was 0.33 (95% CI, 0.17-0.64; P < 0.001) per 1-standard deviation in log urinary CTGF level after adjustment for CKD risk factors, baseline eGFR, and baseline log urinary albumin-creatinine ratio, with similar results in participants without diabetes (n = 184). Results were not materially different when urinary CTGF level was indexed to urinary creatinine level (multivariable-adjusted OR, 0.34; 95% CI, 0.21-0.56; P < 0.001). A similar, but nonsignificant, trend of risk of incident CKD stage 3 with lower baseline urinary CTGF concentration was observed in an independent case-control study conducted in the ARIC Study, with the strongest results observed in participants free of diabetes. This inverse relationship was robust in meta-analysis of both the overall and diabetes-free groups. LIMITATIONS: Observational study; causality cannot be inferred. CONCLUSIONS: Lower urinary CTGF concentrations precede the onset of CKD stage 3 in the general population. Further work is required to fully characterize how CTGF level influences risk of CKD.

Involvement of connective tissue growth factor in human and experimental hypertensive nephrosclerosis.

BACKGROUND/AIMS: Connective tissue growth factor (CTGF; CCN2) has been implicated as a marker and mediator of fibrosis in human and experimental renal disease. METHODS: We performed a comparative analysis of CTGF expression in hypertensive patients with and without nephrosclerosis, and in uninephrectomized and sham-operated spontaneously hypertensive rats (UNX-SHR and 2K-SHR). RESULTS: Urinary and plasma CTGF were elevated in patients with hypertensive nephrosclerosis, and increased renal CTGF expression was mainly localized in podocytes. Accordingly, elevation of urinary, plasma, and tissue CTGF in UNX-SHR coincided and correlated with proteinuria, glomerulosclerosis, and tubulointerstitial fibrosis. Thirty-two weeks after uninephrectomy, mean glomerular CTGF mRNA expression was increased 1.3-fold over baseline, mainly due to 1.7-fold higher expression in glomeruli undergoing sclerosis. In parallel, tubulointerstitial CTGF and α-smooth muscle actin were upregulated in UNX-SHR. CTGF was increased in the media of arcuate and interlobar arteries, while arterioles remained negative. CONCLUSIONS: Glomerulosclerosis, tubulointerstitial fibrosis, and arterial media hypertrophy lesions of hypertensive nephrosclerosis are all characterized by increased CTGF tissue expression, which is associated with a concomitant increase in CTGF in blood and urine. These findings identify CTGF as a promising biomarker for progression of hypertensive nephrosclerosis, and as a likely key factor in the pathogenesis of this disease.

[Urinary connective tissue growth factor as a biomarker chronic allograft nephropathy in a rat model].

OBJECTIVE: To determine whether urinary connective tissue growth factor (CTGF) can be a molecular marker for chronic allograft nephropathy (CAN) in a rat model. METHODS: F344 rat renal grafts were orthotopically transplanted into Lewis rats (n = 24). Lewis rats underwent sham operation as control group (n = 12). Kidney grafts were harvested at Weeks 4, 8, 12 and 16 respectively. Serum creatinine (SCr) was measured. The CAN grades were evaluated according to the Banff 97 schema. The expressions of CTGF in kidney, serum and urine were determined by Western blot and competitive indirect ELISA. Spearman correlation analysis was used to compare CTGF expression and the development of CAN. RESULTS: The expression of CTGF in the graft group was markedly elevated in comparison with the control group. Statistics analysis of CTGF protein in kidney detected by Western blot showed significant differences between these five groups (0.33 ± 0.05 for control, 0.55 ± 0.02 for Week 4, 0.80 ± 0.03 for Week 8, 0.90 ± 0.03 for Week 12 and 1.14 ± 0.11 for Week 16, P < 0.01). Both urine and serum CTGF increased by Week 4 and maintained a high level up to Week 16. The urinary CTGF of renal allografts was (2.9 ± 0.7), (12.9 ± 3.6), (32.3 ± 11.4) and (31.0 ± 8.9) ng/mg creatinine for Weeks 4, 8, 12 and 16 respectively. The urinary levels were positively correlated with SCr, Banff scores and expression of CTGF in the graft kidney (r = 0.848, 0.874, 0.747, all P < 0.01). CONCLUSIONS: CTGF plays a significant role in the pathological changes of CAN after kidney transplantation. Urinary CTGF has the potential as a biomarker for predicting the clinical course of CAN.

Urinary connective tissue growth factor is a biomarker in a rat model of chronic nephropathy.

AIM: This study sought to determine whether urinary connective tissue growth factor (CTGF) was a molecular marker for chronic allograft nephropathy (CAN). METHODS: F344 rat renal grafts orthotopically transplanted into Lewis rats following the procedure of Kamada were harvested at 4,8,12, or 16 weeks. Morphological changes were studied using hematoxylin eosin (HE) and Masson trichrome stains. Serum creatinine (SCr) was measured. CAN grades were evaluated according to the Banff97 schema. Expressions of CTGF in the kidney and urine were determined using real-time polymerase chain reaction (PCR) Western blots, and competitive indirect enzyme-linked immunosorbent assay (ELISA). Spearman correlation analysis was used to compare urinary CTGF expression and CAN development. RESULTS: SCr levels and Banff scores increased in a time-dependent manner. The expression of CTGF in the graft was markedly elevated compared with the control group. Urine CTGF increased by week 4, and maintained high levels up to week 16. The urinary levels correlated positively with the histological presence of CAN. Thus, urine CTGF concentrations reflected the course of CAN, especially at an early stage. CONCLUSION: CTGF plays a significant role in the pathological changes of CAN after kidney transplantation. Urinary CTGF has the potential to be a biomarker for CAN.

Phase 1 study of anti-CTGF monoclonal antibody in patients with diabetes and microalbuminuria.

BACKGROUND AND OBJECTIVES: This report summarizes the first phase 1 trial treating patients with microalbuminuric diabetic kidney disease (DKD) using FG-3019, a human monoclonal antibody to connective tissue growth factor (CTGF). CTGF is critically involved in processes of progressive fibrosis, including DKD. This phase 1, open-label, dose-escalation trial evaluated safety, pharmacokinetics, and possible therapeutic effects of FG-3019 on albuminuria, proteinuria, and tubular proteins. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: Microalbuminuric subjects (n = 24) with type 2 (79%) or type 1 (21%) diabetes received 3 or 10 mg/kg FG-3019 dosed intravenously every 14 days for four doses. Albuminuria and safety follow-up were to days 62 and 365, respectively. RESULTS: No infusion was interrupted for symptoms, although 5 of 24 subjects had mild infusion-day adverse events thought to be possibly drug-related. No subject developed anti-FG-3019 antibodies. FG-3019 clearance was lower at 10 mg/kg than at 3 mg/kg, suggesting a saturable elimination pathway. Although this study was not designed for efficacy testing, it was notable that urinary albumin/creatinine ratio (ACR) decreased significantly from mean pretreatment ACR of 48 mg/g to mean post-treatment (day 56) ACR of 20 mg/g (P = 0.027) without evidence for a dose-response relationship. CONCLUSIONS: Treatment of microalbuminuric DKD subjects using FG-3019 was well tolerated and associated with a decrease in albuminuria. The data demonstrate a saturable pathway for drug elimination, minimal infusion adverse events, and no significant drug-attributable adverse effects over the year of follow-up. Changes in albuminuria were promising but require validation in a prospective, randomized, blinded study.

Renal proximal tubular dysfunction is a major determinant of urinary connective tissue growth factor excretion.

Connective tissue growth factor (CTGF) plays a key role in renal fibrosis. Urinary CTGF is elevated in various renal diseases and may have biomarker potential. However, it is unknown which processes contribute to elevated urinary CTGF levels. Thus far, urinary CTGF was considered to reflect renal expression. We investigated how tubular dysfunction affects urinary CTGF levels. To study this, we administered recombinant CTGF intravenously to rodents. We used both full-length CTGF and the NH(2)-terminal fragment, since the NH(2)-fragment is the predominant form detected in urine. Renal CTGF extraction, determined by simultaneous arterial and renal vein sampling, was 18 +/- 3% for full-length CTGF and 21 +/- 1% for the NH(2)-fragment. Fractional excretion was very low for both CTGFs (0.02 +/- 0.006% and 0.10 +/- 0.02%, respectively), indicating that >99% of the extracted CTGF was metabolized by the kidney. Immunohistochemistry revealed extensive proximal tubular uptake of CTGF in apical endocytic vesicles and colocalization with megalin. Urinary CTGF was elevated in megalin- and cubilin-deficient mice but not in cubilin-deficient mice. Inhibition of tubular reabsorption by Gelofusine reduced renal uptake of CTGF and increased urinary CTGF. In healthy volunteers, Gelofusine also induced an increase of urinary CTGF excretion, comparable to the increase of beta(2)-microglobulin excretion (r = 0.99). Furthermore, urinary CTGF correlated with beta(2)-microglobulin (r = 0.85) in renal disease patients (n = 108), and only beta(2)-microglobulin emerged as an independent determinant of urinary CTGF. Thus filtered CTGF is normally reabsorbed almost completely in proximal tubules via megalin, and elevated urinary CTGF may largely reflect proximal tubular dysfunction.

Urinary connective tissue growth factor increases far earlier than histopathological damage and functional deterioration in early chronic renal allograft injury.

OBJECTIVE: To date, serum biochemistry examination and routine biopsy are the most commonly used methods to assess renal function after allogenic kidney transplantation. Connective tissue growth factor (CTGF) has been considered as a biomarker of chronic renal allograft injury characterized by tubular atrophy and interstitial fibrosis (TA/IF). This study explored the potential value of urinary CTGF as an early predictor of TA/IF using a rat model. MATERIAL AND METHODS: A Fisher to Lewis allogenic rat kidney transplant model was established and the recipients were killed at weeks 4, 8 and 12 post-transplantation. TA/IF was graded based on Banff Schema 1997. The location and expression of CTGF mRNA were detected by oligonucleotide-primed in situ DNA synthesis and quantitative polymerase chain reaction. CTGF protein expression was examined with immunohistochemistry and immunoblotting. Urinary CTGF concentration was measured by enzyme-linked immunosorbent assay. The correlation between urinary CTGF concentration and serum creatinine (SCr) and Banff score was analysed statistically. RESULTS: Typical morphological changes including TA/IF in allograft appeared at week 8 and became very severe at week 12 post-transplantation. CTGF expression in epithelium was up-regulated early and urinary CTGF was markedly elevated from week 4. SCr in recipients was stable before week 8 but increased tremendously at week 12. Urinary CTGF concentration was positively correlated with SCr and degree of interstitial fibrosis. CONCLUSION: Urinary CTGF increases earlier than the appearance of biochemical abnormalities and pathological changes. Measurement of urinary CTGF may offer a potential non-invasive strategy to predict the early onset of chronic renal allograft injury.

Urinary monocyte chemoattractant protein-1 (MCP-1) and connective tissue growth factor (CCN2) as prognostic markers for progression of diabetic nephropathy.

Profibrotic growth factors and inflammatory chemokines have been implicated in the pathogenesis of diabetic nephropathy (DN). However, measurement of urinary monocyte chemoattractant protein-1 (MCP-1) and connective tissue growth factor (CCN2) as prognostic markers has not previously been reported, and neither have two such molecules in urine been examined in a single study of DN. In this prospective observational study, 43 adult diabetic patients were studied, 40 were followed up for 6years. Urinary MCP-1/creatinine ratios were found to be significantly higher in patients with macroalbuminuria (3.3- and 2.1-fold higher (p<0.01) than normoalbuminuric and microalbuminuric patients, respectively). CCN2 exhibited a pattern different from that of urinary MCP-1. Urinary CCN2/creatinine ratios were greatly elevated in both microalbuminuric and macroalbuminuric patients (125- and 74-fold higher than normoalbuminuric patients, respectively, p<0.01 and p<0.05, respectively). Further, urinary CCN2, but not MCP-1, correlated with progression of microalbuminuria (R=0.49, p<0.05). In contrast, MCP-1, but not CCN2, correlated with the rate of eGFR decline for all patients (R=0.61, p<0.0001), reflective of its predictive value in patients with macroalbuminuria, but not for patients with microalbuminuria or normoalbuminuria. In conclusion, increased urinary CCN2 is associated with the early progression of DN, whereas MCP-1 is associated with later stage disease.