Skip Navigation


NDT Advance Access originally published online on January 5, 2007
Nephrology Dialysis Transplantation 2007 22(4):1115-1122; doi:10.1093/ndt/gfl743
This Article
Right arrow Abstract Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
22/4/1115    most recent
gfl743v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (4)
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Bauvois, B.
Right arrow Articles by Jungers, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bauvois, B.
Right arrow Articles by Jungers, P.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author [2007]. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org

Specific changes in plasma concentrations of matrix metalloproteinase-2 and -9, TIMP-1 and TGF-ß1 in patients with distinct types of primary glomerulonephritis

Brigitte Bauvois1,2, Nadya Mothu1, Juliette Nguyen1, Thao Nguyen-Khoa3, Laure-Hélène Nöel1 and Paul Jungers4

1INSERM 507, Hôpital Necker, 2CNRS UMR 7131, Hôpital Broussais-HEGP, 3Laboratoire de Biochimie A, Hôpital Necker and 4Département de Néphrologie, Hôpital Necker, Paris, France

Correspondence and offprint requests to: Dr Brigitte Bauvois, CNRS UMR 7131, Hôpital Broussais-HEGP, 102 rue Didot, 75014 Paris, France. Email: brigitte.bauvois{at}brs.aphp.fr



   Abstract
Top
 Abstract
Introduction
 Subjects and methods
 Results
 Discussion
 Acknowledgements
 References
 
Background. Dysregulated renal expression of matrix metalloproteinases (MMPs), tissue inhibitors of MMPs (TIMP) and TGF-ß1 contribute to the development of tubulo-interstitial fibrosis characteristic of progressive forms of primary glomerulonephritis (GN). There is little information on the circulating levels of these proteins in human GNs. Here, we assessed whether different histopathological GN types could be associated with distinct plasma patterns of MMPs and regulatory proteins.

Methods. Protein levels of MMP-2, MMP-9, TGF-ß1 and TIMP-1 were measured by ELISA in plasma from venous blood of 108 untreated patients with various types of primary GN defined by kidney biopsy, namely IgAN (n = 63), membranous GN (MN, n = 26), minimal change nephrotic syndrome (MCNS, n = 12) and focal and segmental glomerular sclerosis (FSGS, n = 7), and were compared with levels in 50 healthy subjects. Plasma samples were assayed for gelatinolytic activity (zymography).

Results. Zymography detected the proforms of MMP-2 and MMP-9. Compared with controls, IgAN patients exhibited a significant, parallel decrease in plasma levels of MMP-2, MMP-9 and TGF-ß1. In MN patients, decreased MMP-9 level contrasted with a high MMP-2 level and a normal TGF-ß1 level. In the MCNS/FSGS group, increased MMP-2 level contrasted with unchanged MMP-9 and decreased TGF-ß1 levels. Plasma concentration of TIMP-1 was elevated in all GN groups. There was no correlation between baseline MMP-2/MMP-9/TIMP-1/TGF-ß1 levels and the degree of renal dysfunction or with progression toward ESRD.

Conclusions. Plasma concentrations of MMP-2, MMP-9 and TGF-ß1 significantly differed between the various histopathological types of primary GNs, thus suggesting the involvement of different underlying mechanisms in the regulation of glomerular and tubulointerstitial fibrosis in these renal diseases.

Keywords: glomerulonephritis; interstitial fibrosis; matrix metalloproteinase; tissue inhibitor of matrix metalloproteinase; transforming growth factor-ß1



   Introduction
Top
 Abstract
 Introduction
Subjects and methods
 Results
 Discussion
 Acknowledgements
 References
 
Development of progressive renal failure is frequent in chronic glomerular diseases and is mainly attributed to the development of extensive glomerular and interstitial fibrosis [1]. The various types of primary glomerulonephritis (GN) are characterized, from their early phase, by an inflammatory process involving a number of factors released by resident and recruited cells, including proinflammatory cytokines and growth factors such as angiotensin II and transforming growth factor-ß1 (TGF-ß1), whose continuing production leads to the development of glomerular sclerosis and tubulointerstitial fibrosis [2,3]. Ultimately, whatever the initial glomerular events, the development of extensive interstitial fibrosis appears as the common mechanism associated with the loss of renal function and progression toward ESRD [1].

Fibrosis is characterized by the accumulation of extracellular matrix (ECM) components, which results from the imbalance between an excessive ECM production and a defective ECM degradation by proteolytic enzymes [3], among which matrix metalloproteinases (MMPs) play a major role [4]. MMPs are proteolytic zinc-dependent endoproteinases with a pre/pro-peptide domain and a catalytic zinc-binding domain [4]. Their activities are regulated through pro-enzyme activation and interaction with the tissue inhibitors of the MMPs (TIMPs) [5]. In the kidney, MMP-2, MMP-9 and TIMPs are expressed in glomeruli (predominantly in mesangial and epithelial cells) and in tubuli (mainly in proximal tubular cells) [4,6]. These proteins are also expressed by monocytes/macrophages, granulocytes and activated lymphocytes. MMP synthesis is stimulated by inflammatory cytokines including TGF-ß1 [7,8].

Among the MMPs expressed in the kidney, the gelatinases MMP-2 (proform 72 kDa) and MMP-9 (proform 92 kDa) were the most extensively studied because they degrade ECM components present in the glomerular basement membrane as well as in other structures of the kidney [9]. TIMP-1 inhibits the pro and active forms of MMP-9, whereas TIMP-2 is the major inhibitor of proMMP-2 [5].

A number of studies assessed MMP expression in kidney glomeruli and interstitium in animal models mimicking human GNs [6,10–17]. In contrast, a limited number of studies examined the expression of MMPs and their regulatory proteins in human primary chronic GNs [18–21]. They gave discordant conclusions inasmuch as they differed in their study material which consisted of either blood monocytes, serum or kidney biopsy samples. Moreover, most studies to date used serum samples which are convenient for the determination of MMP-2 and TIMP-1, but not of MMP-9. Indeed, serum levels of MMP-9 have been shown to be higher than plasma values due to blood clotting resulting in degranulation of neutrophils and release of stored MMP-9 [22].

In view of the conflicting results of animal and human studies, we hypothesized that different types of primary GNs could be associated with distinct patterns of MMPs and regulatory proteins. The purpose of our study was to determine the plasma levels of MMP-2, MMP-9, TGF-ß1 and TIMP-1 in a large cohort of patients with different types of primary GN defined by kidney biopsy, and to evaluate the possible relationship of these parameters with the degree of interstitial and glomerular fibrosis. In addition, based on the follow-up of patients for up to 10 years, we further examined the relationship between the baseline values of these parameters and progression toward loss of renal function.



   Subjects and methods
Top
 Abstract
 Introduction
 Subjects and methods
Results
 Discussion
 Acknowledgements
 References
 
Patients and healthy control subjects
A total of 108 consecutive adult patients with biopsy-proven GN cared for at our institution between September 1994 and October 1997 were included in an observational cohort study after giving informed consent. Of them, 63 had IgA nephritis (IgAN), 26 membranous glomerulonephritis (MN), 12 minimal change nephrotic syndrome (MCNS) and 7 focal and segmental glomerular sclerosis (FSGS). Only patients with preserved renal function or with mild renal failure, defined by a creatinine clearance ≥60 ml/min/1.73 m2, were eligible for this study. Patients with Henoch–Schönlein purpura, cirrhosis, malignancy, systemic lupus erythematosus, aged <15 years at the time of renal biopsy, and those who received steroid therapy within less than 6 months prior to blood sampling were excluded from the study. None of the patients had been previously transplanted and none received immunosuppressant drugs prior to entry in the study. No patient had recent infection at the time of blood sampling and none was diabetic. The control group consisted of 50 (unmatched) healthy volunteer blood donors from the Blood Bank of Necker Hospital. They were 27 males and 23 females, aged 37.6 ± 2.2 years (mean ± SEM). All were normotensive (mean ± SEM blood pressure 128 ± 2/74 ± 2 mmHg) and had normal renal function.

Design
The starting time for entry in the study (baseline) for each patient was defined when blood was taken. In every patient, we recorded the demographic and clinical data, including age, gender, blood pressure, daily urinary protein excretion (g/24 h), serum albumin (g/l) and serum creatinine (µmol/l) at baseline as well as previous and current treatments, namely corticosteroids, angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II type I receptor blockers (ARBs) and hypolipemic drugs. Presence of the nephrotic syndrome was defined as a serum albumin concentration <30 g/l.

Glomerular filtration rate (GFR) was estimated as the level of creatinine clearance (Ccr) calculated according to the Cockcroft–Gault formula normalized for body surface area and expressed as ml/min/1.73 m2. Follow-up was extended until December 2003 or until start of maintenance dialysis, or death, whichever occurred first. The primary renal endpoint was taken as a final Ccr value <30 ml/min/1.73 m2.

Kidney biopsy samples were reviewed and semiquantitatively scored for fibrosis by one investigator (LHN). Only the 83 biopsies taken at the same time as baseline plasma sampling were considered (in the other 25 patients, kidney biopsy had been performed several years prior to enrolment in the study). Glomerular sclerosis (0–4) was the sum of segmental fibrosis and global glomerular sclerosis (for each, none = 0, <50% = 1 and ≥50% = 2). Interstitial score (0–4) included interstitial fibrosis and cellular infiltrate (same scoring).

Laboratory determinations
Blood samples collected in EDTA tubes were taken within the same period in patients and in control subjects. Plasma was immediately separated, aliquoted and frozen at –80°C until analysis. All plasma samples were stored and processed in an identical fashion. In particular, the time-interval between storage and laboratory determinations was similar in patients and controls. Plasma levels of total (pro + active forms) MMP-2 (DMP200) and total MMP-9 (DMP900) were determined by ELISA kits (R&D, Abingdon, UK). Plasma levels of the proform of MMP-2 were measured by using the enzyme-linked immunosorbent assay (ELISA) kit (RPN 2617) according to the manufacturer's instructions (Amersham Biosciences, Buckinghamshire, UK). TGF-ß1 and TIMP-1 were determined by using the commercial ELISA kits from R&D (DB100 and DTM100, respectively).

Gelatinolytic activities of MMP-2 and MMP-9 were detected by zymography. Plasma (5 µl) samples were diluted in non-reducing sample buffer and loaded on to 7.5% SDS–polyacryamide gels containing copolymerized gelatin (1%, w/v) (Sigma Chemicals Co., Saint Louis, MO), and electrophoresis was performed at constant voltage (80 V) for 2 h at 4°C. The gels were then rinsed twice with 2.5% Triton X-100 in 50 mM HCl-buffer pH 7.5 and incubated overnight at 37°C in 50 mM Tris–HCl buffer pH 7.6 containing 10 mM CaCl2, 150 mM NaCl and 0.05% NaN3 with gentle agitation. The gels were stained with Eza-Blue staining gel (Sigma) and MMP activities were detected as transparent bands on the blue background of the stained gel. Recombinant proMMP-9 and proMMP-2 (R&D) were used as internal positive controls. The NIH Image 1.63 software was used for analysis of the bands after acquisition in an Appligen densitometer (Oncor).

Statistical analyses
Data were expressed as mean ± SEM unless otherwise specified. Comparisons of groups were done by Student t-test or analysis of variance (ANOVA). Differences in frequencies were determined by chi-square analysis. Standard regression analysis and Pearson and Spearman correlation coefficients were used to determine the relationships between MMPs, TIMP-1, TGF-ß1, Ccr and fibrosis scores.

Multivariate Cox proportional analysis was used to test parameters related to renal outcome from baseline to renal endpoint. Laboratory parameters considered were plasma levels of MMP-2, MMP-9, TIMP-1 and TGF-ß1. Only variables which revealed significance at P < 0.10 at univariate Cox analysis were entered in the multivariate model. Because the characteristics of IgAN patients differed in several ways from those of patients with other types of GN, Cox proportional analysis was additionally performed on GN subsets separately. All tests were performed using NCSS 2000 software (Jerry L. Hintze, Kaysville, UT, USA).



   Results
Top
 Abstract
 Introduction
 Subjects and methods
 Results
Discussion
 Acknowledgements
 References
 
Clinical characteristics of study population
Demographic and clinical characteristics of patients in the four types of GN are presented in Table 1. Of the 108 patients (97% Caucasian), 75 were males and 33 were females. Their age at entry in the study ranged from 18 to 75 years. The median duration from baseline to end of follow-up was 5.3 years (range 1–9.3 years). Their Ccr value at baseline ranged from 60 to 103 ml/min/1.73 m2. The male-to-female ratio was higher in the IgAN group than in the other groups. The mean age at entry in the study was significantly higher in the MN and FSGS groups than in the IgAN and MCNS groups. Baseline proteinuria was markedly lower in the IgAN group than in the other groups. Accordingly, mean serum albumin levels were higher in IgAN patients than in the other groups. No patient was nephrotic in the IgAN group, whereas more than half of the patients were nephrotic at baseline in the other groups.


View this table:
[in this window]
[in a new window]

  		Table 1. Demographic and clinical characteristics of patients in the four groups of primary GN at baseline and at end of follow-up

 
Gelatinolytic activities of plasma MMP-2 and MMP-9 in controls and GNs
Proteolytic activity of MMP-2 and MMP-9 in plasma samples was assessed by gelatin substrate zymography. Zymography analysis of five representative samples from controls and from the four GN groups revealed the expression of both proforms of MMP-2 (72 kDa) and MMP-9 (92 kDa) in all samples (Figure 1A). Densitometric analysis of proMMP values in 10 controls and 38 GN patients (10 MCNS, 10 MN, 7 MN and 11 IgAN) revealed a significant decrease of proMMP-9 and proMMP-2 activities in the IgAN group (P < 0.05) (Figure 1B and C). Very faint bands corresponding to the proteolytically cleaved active form (84 kDa) attributable to MMP-9 were visible in some zymograms (Figure 1A) (<5%).


Figure 1
View larger version (75K):
[in this window]
[in a new window]
[Download PowerPoint slide]
  		Fig. 1. Zymography of MMP-2 and MMP-9 in plasma. (A) Representative MMP zymography of five samples from each GN (MCNS, FSGS, MN, IgAN) and controls. Aliquots of 5 µl of plasma from controls and GNs were loaded. Bands corresponding to the proforms of MMP-9 and MMP-2 are identified by the arrows on the left. (B) and (C) Densitometry of gelatinolytic activity (arbitrary units/5 µl plasma, ±SEM) of proMMP-9 (B) and proMMP-2 (C) in 10 controls vs 10 MCNS, 7 FSGS, 10 MN and 11 IgAN. *P < 0.05 compared with the control group.

 
Plasma protein MMP-2 levels
Because interpretation of MMP-2 zymographic profiles was disputable in some samples, we verified the relative amounts of proMMP-2 and active MMP-2 using specific ELISA assays, which determined respectively the amounts of total (pro + active) MMP-2 and proMMP-2 in plasma samples (19 controls, 10 MCNS, 7 FSGS, 24 MN and 29 IgAN). As shown in Figure 2, the level of proMMP-2 did not significantly differ from that of total MMP-2 both in controls and in the various GN groups. This further indicates that the total ELISA assay of MMP-2 measured essentially its proform. Figure 2 points out that circulating levels of MMP-2 determined by total MMP-2 assay as well as by proMMP-2 assay showed similar patterns with significantly decreased MMP-2 levels in IgAN patients as compared with controls and other types of GN.


Figure 2
View larger version (14K):
[in this window]
[in a new window]
[Download PowerPoint slide]
  		Fig. 2. Concentration of total MMP-2 and proMMP-2 in plasma. ELISA analysis of total (pro + active) MMP-2 and proMMP-2 plasma levels of control subjects (19) and patients with MCNS (10), FSGS (7), MN (24) or IgAN (29).

 
Plasma levels of MMP-2, MMP-9, TIMP-1 and TGF-ß1
Mean plasma levels of total MMP-2, total MMP-9, TIMP-1 and TGF-ß1 in the four groups of GN and controls as determined by ELISA asssays are shown in Table 2. Compared with controls, plasma level of MMP-9 was significantly lower in the IgAN and MN groups, whereas it did not significantly differ in the FSGS and MCNS groups. Plasma MMP-2 level was significantly lower in the IgAN group, whereas it was higher in the other three GN groups. Plasma level of TGF-ß1 was lower in IgAN and FSGS groups, whereas it did not differ from controls in the MN and MCNS groups. Plasma level of TIMP-1 was increased in all GN groups compared with controls. Plasma levels of MMP-2, TGF-ß1 and TIMP-1 were all significantly lower in patients with serum albumin <30 g/l, while MMP-9 levels were not affected (data not shown). Plasma levels of these parameters did not differ between the 26 IgAN patients who were treated with ACEIs or ARBs and the 37 who were not. Plasma concentrations in treated and untreated patients were, respectively, 12.8 ± 4.5 vs 11.5 ± 3.5 ng/ml (P = 0.81) for MMP-9, 132 ± 17 vs 111 ± 13 ng/ml (P = 0.32) for MMP-2, 8.6 ± 1.5 vs 9.2 ± 1.2 ng/ml (P = 0.73) for TGF-ß1 and 175 ± 12 vs 151 ± 10 ng/ml (P = 0.12) for TIMP-1.


View this table:
[in this window]
[in a new window]

  		Table 2. Baseline laboratory values in the four groups of primary GN compared with healthy controls

 
Relationship between plasma levels of MMPs, TIMP-1, TGF-ß1 and Ccr
In the IgAN group, there was a positive correlation between plasma MMP-2 and MMP-9 (r = 0.36; P = 0.0039); plasma TGF-ß1 had a positive association with plasma MMP-9 (r = 0.32; P = 0.009) and MMP-2 (r = 0.31; P = 0.012), whereas TIMP-1 did not correlate with any MMP nor with TGF-ß1. In the MN group, there was only a positive correlation between MMP-9 and TGF-ß1 (r = 0.55; P = 0.0036). In the FSGS group, MMP-9 did not correlate with any of the other parameters, whereas MMP-2 was positively associated with TIMP-1 (r = 0.86; P = 0.012). In the MCNS group, no correlation appeared between the studied parameters. In all groups, Ccr values did not correlate with plasma MMP-2, MMP-9, TGF-ß1 and TIMP-1 concentrations.

Relationship between MMPs and fibrosis
Correlations between MMP/TIMP plasma levels and fibrosis scores were evaluated in the 83 patients whose kidney biopsy was contemporary with baseline plasma sampling. Excluded from this analysis were 10 kidney biopsies from MCNS patients who did not exhibit any significant glomerular or interstitial fibrosis. In the IgAN group, glomerular sclerosis and interstitial fibrosis score correlated together (r = 0.55; P < 0.0001) and interstitial fibrosis correlated with TIMP-1 1evel (r = 0.54; P = 0.0003). Ccr had a strong negative correlation with TIMP-1 (r = –0.67; P < 0.0001) and with both glomerular sclerosis (r = –0.36; P = 0.015) and interstitial fibrosis (r = –0.74; P < 0.0001). In the MN group, glomerular sclerosis had a positive correlation with MMP-2 (r = 0.48; P = 0.0222), whereas interstitial fibrosis is negatively correlated with Ccr (r = –0.60; P = 0.003). In the FSGG group, a unique correlation was found between glomerular sclerosis and MMP-2 level (r = 0.91; P = 0.03).

Renal survival
At the end of follow-up, 30 of the 108 patients had reached the advanced stage of renal failure as defined by a Ccr value ≤30 ml/min/1.73 m2 (Table 1) including 12 who started maintenance dialysis. The proportion was similar in the IgAN, MN and FSGS groups (close to 30%), whereas no progression toward renal insufficiency was observed in the MCNS group. By univariate Cox regression analysis, neither MMP-2/MMP-9 nor TGF-ß1 or TIMP-1 were significantly associated with the risk of poor final renal outcome, both in the whole series and in the various GN groups. By multivariate analysis (Table 3), only baseline Ccr and interstitial fibrosis score were significant predictors of the risk in the whole series. In the IgAN group, interstitial fibrosis score and baseline proteinuria were independent predictors, whereas in the MN group only the interstitial fibrosis score was predictive. Patients in the FSGS group were too few to allow multivariate analysis.


View this table:
[in this window]
[in a new window]

  		Table 3. Multivariate Cox regression analysis for factors independently associated with poor renal outcome (final Ccr <30 ml/min/1.73 m2)

 


   Discussion
Top
 Abstract
 Introduction
 Subjects and methods
 Results
 Discussion
Acknowledgements
 References
 
The present study evaluated for the first time the plasma levels of MMP-2 and MMP-9 and related biomarkers in a large series of patients with various, well-defined types of primary GN. Data obtained from zymographic analysis and ELISA assays showed that MMP-2 and MMP-9 found in the plasma of controls and GN patients were almost entirely their proforms. Two main findings emerge from our study. First, there were marked, significant differences in the plasma levels of MMP-2/MMP-9, TIMP-1 and TGF-ß1 between patients with primary GN and healthy controls. Second, and more important, plasma patterns of MMPs and regulatory proteins considerably differed between the various histopathological types of GN, and therefore appear to be characteristic of each type of GN. Moreover, with the exception of TIMP-1, whose plasma concentration inversely varied with Ccr, plasma concentrations of MMP-2/MMP-9 and TGF-ß1 did not significantly vary with the level of renal function, at variance with proinflammatory cytokines whose plasma concentrations were previously shown to increase in parallel with the decline in renal function [23]. Because these alterations were observed at the early stage of the disease, these findings suggest that distinct mechanisms are acting in the various types of GN.

In our series of 63 IgAN patients, we observed decreased levels of plasma MMP-9, MMP-2 and TGF-ß1 contrasting with an increased TIMP-1 level, as compared with healthy controls. In addition, there was a positive correlation between plasma concentrations of MMP-9 and TGF-ß1 in these patients. Similarly, in 34 IgAN patients studied by Akiyama et al. [19], serum MMP-2 levels were lower and TIMP-1 higher than in healthy controls; MMP-9 and TGF-ß1 were not evaluated in this study. Koide et al. [18] observed increased TGF-ß1 and MMP-9 mRNA expression contrasting with low MMP-2 mRNA expression in circulating monocytes from 50 IgAN patients. In kidney biopsy samples from 20 IgAN patients, Urushihara et al. [20] observed an enhanced MMP-9 expression in proliferative mesangial areas of glomeruli. Murine models of mesangial proliferative GN using a single injection anti-Thy1-1 monoclonal antibody induce an acute, spontaneously reversible mesangial proliferation, and therefore do not reproduce the human disease. Models using repeated injections are more relevant to human IgAN. Following two consecutive injections of anti-Thy-1.1 antibody in rats, Tomita et al. [17] observed a 76% decrease in mesangial MMP-9 mRNA expression at week 8. In a chronic model (four injections), Harendza et al. [13] observed a decreased MMP-9 mRNA expression contrasting with an augmented expression of MMP-2 and TGF-ß1 in proliferative mesangial cells. Thus, the marked decrease in MMP-9 plasma concentrations in human IgAN as observed in our patients is in accordance with its decreased renal expression in animal models, whereas MMP-2 and TGF-ß1 expression differed between humans and murine models.

In 26 MN patients, we observed a very different pattern with a decrease in plasma MMP-9 contrasting with an increase in MMP-2 and TIMP-1, whereas plasma TGF-ß1 was not significantly affected. Similarly, Akiyama et al. [19] reported increased serum levels of MMP-2 and TIMP-1 in 12 patients with MN. Lods et al. [21] also observed enhanced serum MMP-2 and TIMP-1 levels in 10 patients, of whom 4 had MN, with a decreased expression of MMP-9. In contrast, Koide et al. [18] reported no significant variation in MMP-2 and MMP-9 mRNA expression in peripheral blood monocytes of 20 MN patients. In rats with passive Heymann nephritis, a model representative of human MN, Mc Millan et al. [10] observed an increased expression of MMP-9 in cultured glomerular epithelial cells, which temporally correlated with proteinuria, thus suggesting a role for MMP-9 in the breakdown of the glomerular basement membrane; the circulating MMP-9 level was not determined in this study.

In the MCNS/FSGS nephrosis group, plasma concentrations of MMP-9 were unchanged, contrasting with increased MMP-2 and TIMP-1 levels, whereas TGF-ß1 levels were decreased in the FSGS group and unchanged in the MCNS group. Lods et al. [21] observed a reduced serum MMP-9 level accompanied by increased MMP-2 and TIMP-1 serum levels in their series of 10 GN patients of whom 4 had FSGS. In hereditary nephrotic mice, a model of severe nephrosis leading to renal failure, Uchio et al. [14] observed lower MMP-2 and MMP-9 gelatinolytic activities in kidney tissue extracts accompanied by an accumulation of ECM components. Therefore, no consistent conclusions emerged from these human and animal studies, possibly due to the heterogeneity of this group of GNs. However, our data indicate that the plasma profiles of MMP/TGF-ß1 in the FSGS/MCNS group appear distinct from those observed in the IGAN and MN groups.

Circulating levels of MMPs presumably reflect their expression in the kidney. Indeed, Lods et al. [21] previously observed that MMP-2/MMP-9 levels in the serum of 10 GN patients (including 4 FSGS and 4 MN) paralleled their expression in kidney biopsies as determined by immunohistology. The observation that plasma patterns of MMP-2/MMP-9 and TGF-ß1 considerably differed between IgAN, MN, FSGS and MCNS groups suggests that distinct pathogenetic mechanisms are acting in the development of renal fibrosis in these various types of GNs. However, since we did not concurrently evaluate the expression of MMPs in the renal tissue and in the plasma of our patients, we could not determine to which extent circulating levels of MMPs reflect their intrarenal expression.

An important issue is whether baseline plasma levels of MMP-2, MMP-9, TGF-ß1 and TIMP-1 are predictive of the development of renal insufficiency and progression toward ESRD. In the present study, no correlation was found in the whole cohort between plasma levels of MMP-2, MMP-9 or TGF-ß1 and the degree of dysfunction evaluated by Ccr, whereas the plasma concentrations of TIMP-1 rose with lower Ccr values. Accordingly, Cox model analysis of the factors predictive of poor renal outcome did not identify any predictive value for baseline MMP-2, MMP-9, TGF-ß1 or TIMP-1 plasma concentrations in any of the GN groups, whereas, as expected, baseline proteinuria and interstitial fibrosis were strong predictors. Thus, altered plasma patterns of MMPs and their regulatory proteins in the four groups of GN appear of pathophysiological rather than of prognostic significance.

In conclusion, our study confirms that plasma levels of MMP-2, MMP-9, TIMP-1 and TGF-ß1 are markedly altered in patients with primary GNs as compared with healthy subjects. Moreover, our data provide for the first time convincing evidence that the profiles of MMP/TIMP-1/TGF-ß1 plasma concentrations significantly differ between the various histopathological types of primary GNs, thus suggesting the involvement of different mechanisms in the regulation of glomerular and tubulointerstitial fibrosis. However, no significant relationship between plasma MMP concentration and the level of estimated GFR was found. Whether circulating levels of MMPs will change in response to immunomodulating and/or antifibrotic strategies remains to be determined.



   Acknowledgements
Top
 Abstract
 Introduction
 Subjects and methods
 Results
 Discussion
 Acknowledgements
References
 
This work was supported by grant AO94047 from the Délégation à la Recherche Clinique/Assistance Publique-Hôpitaux de Paris, and grants from the Institut National de la Santé et de la Recherche Médicale, and La Fondation pour La Recherche Médicale.

Conflict of interest statement. None declared.



   References
Top
 Abstract
 Introduction
 Subjects and methods
 Results
 Discussion
 Acknowledgements
 References
 

  1. Nath KA. (1992) Tubulointerstitial changes as a major determinant in the progression of renal damage. Am J Kidney Dis 20:1–17.[Web of Science][Medline]
  2. Floege J and Grone HJ. (1995) Progression of renal failure: what is the role of cytokines? Nephrol Dial Transplant 10:1575–1586.[Free Full Text]
  3. Eddy AA. (1996) Molecular insights into renal interstitial fibrosis. J Am Soc Nephrol 7:2495–2508.[Abstract]
  4. Lenz O, Elliot SJ, Stetler-Stevenson WG. (2000) Matrix metalloproteinases in renal development and disease. J Am Soc Nephrol 11:574–581.[Free Full Text]
  5. Baricos WH. (1995) Chronic renal disease: do metalloproteinase inhibitors have a demonstrable role in extracellular matrix accumulation? Curr Opin Nephrol Hypertens 4:365–368.[Medline]
  6. Turck J, Pollock AS, Lee LK, Marti HP, Lovett DH. (1996) Matrix metalloproteinase 2 (gelatinase A) regulates glomerular mesangial cell proliferation and differentiation. J Biol Chem 271:15074–15083.[Abstract/Free Full Text]
  7. Marti HP, Lee L, Kashgarian M, Lovett DH. (1994) Transforming growth factor-beta 1 stimulates glomerular mesangial cell synthesis of the 72-kd type IV collagenase. Am J Pathol 144:82–94.[Abstract]
  8. Nee LE, McMorrow T, Campbell E, Slattery C, Ryan MP. (2004) TNF-alpha and IL-1beta-mediated regulation of MMP-9 and TIMP-1 in renal proximal tubular cells. Kidney Int 66:1376–1386.[CrossRef][Web of Science][Medline]
  9. Mandal M, Mandal A, Das S, Chakraborti T, Sajal C. (2003) Clinical implications of matrix metalloproteinases. Mol Cell Biochem 252:305–329.[CrossRef][Web of Science][Medline]
  10. McMillan JI, Riordan JW, Couser WG, Pollock AS, Lovett DH. (1996) Characterization of a glomerular epithelial cell metalloproteinase as matrix metalloproteinase-9 with enhanced expression in a model of membranous nephropathy. J Clin Invest 97:1094–1101.[Web of Science][Medline]
  11. Ebihara I, Nakamura T, Tomino Y, Koide H. (1997) Effect of a specific endothelin receptor A antagonist and an angiotensin-converting enzyme inhibitor on glomerular mRNA levels for extracellular matrix components, metalloproteinases (MMP) and a tissue inhibitor of MMP in aminonucleoside nephrosis. Nephrol Dial Transplant 12:1001–1006.[Abstract/Free Full Text]
  12. Steinmann-Niggli K, Lukes M, Marti HP. (1997) Rat mesangial cells and matrix metalloproteinase inhibitor: inhibition of 72-kD type IV collagenase (MMP-2) and of cell proliferation. J Am Soc Nephrol 8:395–405.[Abstract]
  13. Harendza S, Schneider A, Helmchen U, Stahl RA. (1999) Extracellular matrix deposition and cell proliferation in a model of chronic glomerulonephritis in the rat. Nephrol Dial Transplant 14:2873–2879.[Abstract/Free Full Text]
  14. Uchio K, Manabe N, Tamura K, et al. (2000) Decreased matrix metalloproteinase activity in the kidneys of hereditary nephrotic mice (ICGN strain). Nephron 86:145–151.[CrossRef][Web of Science][Medline]
  15. Lelongt B, Legallicier B, Piedagnel R, Ronco PM. (2001) Do matrix metalloproteinases MMP-2 and MMP-9 (gelatinases) play a role in renal development, physiology and glomerular diseases? Curr Opin Nephrol Hypertens 10:7–12.[Web of Science][Medline]
  16. Fornoni A, Wang Y, Lenz O, Striker LJ, Striker GE. (2002) Association of a decreased number of d(CA) repeats in the matrix metalloproteinase-9 promoter with glomerulosclerosis susceptibility in mice. J Am Soc Nephrol 13:2068–2076.[Abstract/Free Full Text]
  17. Tomita M, Koike H, Han GD, Shimizu F, Kawachi H. (2004) Decreased collagen-degrading activity could be a marker of prolonged mesangial matrix expansion. Clin Exp Nephrol 8:17–26.[CrossRef][Medline]
  18. Koide H, Nakamura T, Ebihara I, Tomino Y:. (1996) Increased mRNA expression of metalloproteinase-9 in peripheral blood monocytes from patients with immunoglobulin A nephropathy. Am J Kidney Dis 28:32–39.[Web of Science][Medline]
  19. Akiyama K, Shikata K, Sugimoto H, et al. (1997) Changes in serum concentrations of matrix metalloproteinases, tissue inhibitors of metalloproteinases and type IV collagen in patients with various types of glomerulonephritis. Res Commun Mol Pathol Pharmacol 95:115–128.[Web of Science][Medline]
  20. Urushihara M, Kagami S, Kuhara T, Tamaki T, Kuroda Y. (2002) Glomerular distribution and gelatinolytic activity of matrix metalloproteinases in human glomerulonephritis. Nephrol Dial Transplant 17:1189–1196.[Abstract/Free Full Text]
  21. Lods N, Ferrari P, Frey FJ, et al. (2003) Angiotensin-converting enzyme inhibition but not angiotensin II receptor blockade regulates matrix metalloproteinase activity in patients with glomerulonephritis. J Am Soc Nephrol 14:2861–2872.[Abstract/Free Full Text]
  22. Jung K, Lein M, Laube C, Lichtinghagen R. (2001) Blood specimen collection methods influence the concentration and the diagnostic validity of matrix metalloproteinase 9 in blood. Clin Chim Acta 314:241–244.[CrossRef][Web of Science][Medline]
  23. Descamps-Latscha B, Herbelin A, Nguyen AT, et al. (1995) Balance between IL-1 beta, TNF-alpha, and their specific inhibitors in chronic renal failure and maintenance dialysis. Relationships with activation markers of T cells, B cells, and monocytes. J Immunol 154:882–892.[Abstract]
Received for publication: 4. 1.06
Accepted in revised form: 15.11.06


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 Nephrol Dial TransplantHome page
M. Wornle, M. Roeder, M. Sauter, and A. Ribeiro
Role of matrix metalloproteinases in viral-associated glomerulonephritis
Nephrol. Dial. Transplant., April 1, 2009; 24(4): 1113 - 1121.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
22/4/1115    most recent
gfl743v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (4)
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Bauvois, B.
Right arrow Articles by Jungers, P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bauvois, B.
Right arrow Articles by Jungers, P.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?