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Articles |
1
Institute of Clinical Chemistry I,
2
Department of Gastroenterology and Hepatology, and
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Institute of Pathology, Medizinische Hochschule, D-30623 Hannover, Germany.
a Address correspondence to this author at: Abteilung Gastroenterologie und Hepatologie, Medizinische Hochschule Hannover, D-30623 Hannover, Germany. Fax 49-511-532-5692; e-mail Boeker.Klaus{at}mh-hannover.de
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Abstract |
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Methods: Quantitative reverse transcription-PCR/ELISA assays were performed for MMP and TIMP RNA, and corresponding circulating protein concentrations were studied by ELISA in 20 healthy controls, 40 patients with CAH, and 20 patients with hepatitis C-induced cirrhosis (Ci).
Results: MMP-2 mRNA was found almost exclusively in the liver, MMP-9 mRNA in leukocytes. TIMP RNA-equivalents were decreased in MNLs of CAH patients, but neither MMP-9 nor TIMP RNA expression showed any correlation to the extent of inflammation and fibrosis. MMP-2 and TIMP-1 protein concentrations were increased in Ci patients and showed a wide overlap in CAH patients and healthy controls. MMP-9 values were lower in CAH and Ci patients than in healthy controls. TIMP-2 values showed a wide overlap in all three groups. The MMP-2/TIMP-1 and MMP-9/TIMP-1 ratios were lower in Ci patients than in healthy controls; the MMP-2/TIMP-2 and MMP-9/TIMP-2 ratios were not different. Circulating TIMP-1 and the MMP-2/TIMP-1 ratio correlated to the inflammatory activity in liver biopsies, but only the circulating MMP-2/TIMP-1 ratio also correlated with the degree of fibrosis.
Conclusions: Peripheral blood cell expression of MMP-2, MMP-9, and TIMP revealed no correlation with the circulating concentrations of these proteins. Only the circulating MMP-2/TIMP-1 ratio correlated to the histological degree of fibrosis in hepatitis C and should be further evaluated as a progression marker in patients with chronic liver disease.
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Several biochemical indicators have been discussed as potential noninvasive serum/plasma markers of fibroproliferation. Among them the matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) have been shown by several groups to correlate more or less closely with the development of Ci, the extent of toxic damage to the liver in alcoholic liver disease, and the inflammatory activity in patients with chronic viral hepatitis (1)(2)(3)(4)(5)(6)(7)(8).
Hepatic fibrosis is the result of an imbalance between enhanced matrix synthesis and diminished breakdown of connective tissue proteins, the net result of which is increased deposition of extracellular matrix. In this concept, MMPs play an important role because their activity is largely responsible for matrix breakdown (9)(10). Among the family of zinc-containing enzymes collectively named MMPs, different groups can be distinguished according to their substrate specificity (11).
Gelatinases (type IV collagenases) may be especially important for the development of organ fibrosis because they degrade type IV (basal membrane) collagen and thus are involved in the early steps of tissue remodeling that characterizes chronic liver diseases (12)(13).
Most studies have assessed the circulating concentrations of different MMPs and TIMPs in peripheral blood, assuming that a substantial amount of the circulating enzymes and inhibitors derives from the liver. However, little is known about the cellular sources of circulating MMPs and TIMPs. Therefore, we investigated the expression of MMP-2 (gelatinase A; 72-kDa type IV collagenase), MMP-9 (gelatinase B; 92-kDa type IV collagenase), TIMP-1, and TIMP-2 in circulating peripheral blood cells and compared this expression to the circulating concentrations of protease and inhibitor protein. The results were correlated to the histologic findings in liver biopsies.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Forty patients with hepatitis C virus (HCV) infection and histologically confirmed chronic active hepatitis (CAH), and 20 patients with histologically confirmed, HCV-induced end-stage liver Ci were studied. Histologic activity of both inflammation and fibrosis were assessed in liver biopsies taken at the same time as the blood samples. The hepatic activity index proposed by Ishak et al. (14) was used for quantification of inflammation and fibrosis.
In all studied patients and controls, chest-x-rays, abdominal
ultrasound examinations, and determination of 
-fetoprotein, CEA, and
CA 19-9 serum concentrations were performed to exclude the presence of
tumors.
All patients and controls were informed about the rationale and possible risks of the study and gave written informed consent before inclusion. The study protocol was approved by the ethics committee of the Medizinische Hochschule Hannover.
mononuclear and polymorphonuclear leukocyte separation and
isolation of rna
EDTA-anticoagulated blood was centrifuged within 30 min after
venipuncture, using Polymorphprep® tubes
(Nycomed). Separated peripheral blood mononuclear leukocytes
(MNLs) and polymorphonuclear leukocytes (PMLs) were counted in a
Sysmex® K-1000 hemocytometer, lysed in DNA/RNA
Stabilization Reagent for Blood/Bone Marrow®
(Roche Diagnostics), and stored at -70 °C. Total RNA was extracted
from aliquots of 106 peripheral blood mononuclear
cells per patient/control by a standard protocol (High Pure RNA
Isolation Kit®; Roche Diagnostics). The protocol
contained a DNase digestion step for elimination of DNA contamination.
RNA corresponding to 105 cells was applied to a
single PCR assay. For reasons of quality control, RNA quantification
was performed with a RiboGreen® RNA Quantitation
Kit (MoBiTec) on a F-2000 fluorescence spectrophotometer (Hitachi).
Liver RNA was extracted from 15 mg wet weight of hepatic tissue with
the High Pure RNA Isolation Kit. RNA was eluted in 100 µL of
RNase-free water, and 10-µL aliquots were used for amplification.
competitive reverse transcription-pcr
Competitive reverse transcription (RT)-PCR was performed using the
Titan One Tube RT-PCR System® (Roche
Diagnostics) and the following cycling conditions: 1 cycle at 50 °C
for 30 min, and 35 cycles at 94 °C for 45 s, 58 °C for
45 s, and 72 °C for 90 s. The following primer pairs were
used (1 µmol/L final concentration):
MMP-2 (15): 5'-CTC TCC TGA CAT TGA CCT TGG CAC-3' (upstream) and 5'-AAA AAG CTT ACT CGC TGG ACA TCA GGG-3' (downstream);
MMP-9 (16): 5'-GGC ATC CGG CAC CTC TAT GGT CC-3' (upstream) and 5'-GCC ACT TGT CGG CGA TAA GGA AGG-3' (downstream);
TIMP-1 (17): 5'-CTG TTG GCT GTG AGG AAT GCA CAG-3' (upstream) and 5'-TTC AGA GCC TTG GAG GAG CTG GTC-3' (downstream);
TIMP-2 (18): 5'-ATG AGA TCA AGC AGA TAA AGA TG-3' (upstream) and 5'-GGT CCT CGA TGT CGA GAA ACT C-3' (downstream).
Fixed amounts of in vitro-synthesized competitor RNA for MMP-9, TIMP-1, and TIMP-2 were added. The same primer pairs bound to cDNA of competitor RNA and natural mRNA origin, respectively, but differences in the sequences of both cDNAs enabled hybridization with different capture probes for ELISA detection. For purposes of validation and calibration of the procedure, various amounts of in vitro-transcribed RNA (105, 106, 107, 108, and 109 molecules) equal to the mRNA for MMP-9, TIMP-1, and TIMP-2 were coamplified with 106 molecules of competitor RNA for quantification of MMP-9 and TIMP-2 or with 108 molecules for quantification of TIMP-1. The concentration of in vitro-transcribed RNA was determined photometrically at 260/280 nm. For labeling of PCR products, digoxigenin-11-dUTP (final concentration, 6 µmol/L; Roche Diagnostics) was added to be incorporated during amplification.
quantification of pcr products
For quantification of amplified cDNA, an ELISA procedure (Enzymun
Test®; Roche Diagnostics) was performed on an
automated ES-300 analyzer (Roche Diagnostics) according to the
manufacturer’s instructions as described previously (19).
In the first step, different biotinylated oligonucleotides for
hybridization with amplified cDNA of sample mRNA origin and competitor
RNA origin, respectively, were used as capture probes to bind PCR
products to the solid phase. The following capture probes used:
MMP-9 capture probe: biotin-5'-GGG AAG TAC TGG CGA TTC TC-3';
MMP-9 competitor capture probe: biotin-5'-GGG AAG GAT CCC GCA TTC TC-3';
TIMP-1 capture probe: biotin-5'-ACT GCA GAG TGG CAC TCA TTG CT-3';
TIMP-1 competitor capture probe: biotin-5'-CTG CAG TGA GGA TCC CAT TG-3';
TIMP-2 capture probe: biotin-5'-GAG TGC CTC TGG ATG GAC TG-3';
TIMP-2 competitor capture probe: biotin-5'-GAG TGC CAG AGG ATC CAC TG-3'.
In the second step, peroxidase-conjugated antibodies against digoxigenin were added. After addition of the chromogen 2,2'-azino-bis(3-ethylbenz-thiozoline-6-sulfonic acid), the absorbance at 405 nm was measured. This procedure of separate hybridization with different capture probes yielded signals equivalent to the amount of cDNA of sample mRNA origin and competitor RNA origin, respectively. Results were expressed as the ratio of these signals (cDNA/cDNAcompetitor). Various amounts of template in combination with a fixed amount of a competitor should yield a linear curve in a double-logarithmic plot expressing the amount of a varying template on one scale and the ratio of both PCR products (template/competitor) on the other scale. RNA-equivalents per cell were calculated from calibration curves based on in vitro-transcribed calibrator cRNA. Data for each calibration curve were calculated from means of different measurements under identical assay conditions (n = 8) by linear regression. These data (y = ax + b) were calculated for TIMP-1 (a = -4.4; b = 0.555; r = 0.9997), TIMP-2 (a = -4.83; b = 0.706; r = 0.998), and MMP-9 (a = -4.997; b = 0.645; r = 0.9999), respectively.
evaluation of the rt-pcr assay
To provide precision data, RNA isolations and subsequent
competitive RT-PCR ELISAs from pooled MNLs and PMLs were performed
separately at eight different times. Table 1
shows the evaluation data with the coefficients of variation
(CVs), which were, on average, ~23% for the absorbance
ratios (template/competitor) and 37% for the RNA-equivalents/cell data
derived from the mean calibration curves, as described above.
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cloning of calibrators
As described earlier, nucleotides 387–710 of TIMP-1, nucleotides
474–1007 of TIMP-2 (1), and nucleotides 1319–1938 of MMP-9
cDNA (20) were cloned in pBluescript KS+ (Stratagene) using
PCR primers with flanking EcoRI and HindIII
restriction sites. For the construction of internal standards, several
base substitutions were introduced into the capture probe binding
region by two PCR primers with flanking BamHI restriction
sites. Two different amplifications were performed as described
previously (19) with these primers in combination with the
outer primers, yielding EcoRI/BamHI and
BamHI/HindIII DNA fragments that were joined
together by ligation with an EcoRI/HindIII
pBluescript KS+ vector. The sequences of the BamHI flanking
primers for introducing of the mismatches were as follows:
MMP-9: 5'-GAA GGA TCC CGC ATT CTC TGA GGG CAG GGG-3' (upstream) and 5'-CGC GGA TCC TTC CCA TCC TTG AC AAA TAC-3' (downstream);
TIMP-1: 5'-AGT GGA TCC CAT TGC TTG TGG ACG GAC CAG-3' (upstream) and 5'-ATG GGA TCC TCA CTG CAG TTT GCA GGG GAT GGA-3' (downstream);
TIMP-2: 5'-TCT GGA TCC ACT GGG TCA CAG AGA AGA AC-3' (upstream) and 5'-AGT GGA TCC TCT GGC ACT CGT CCG GGG AGG-3' (downstream).
Plasmid clones were purified with the QiaAmp Plasmid Kit (Qiagen). Plasmid DNA (1 µg) was linearized with restriction endonuclease NotI, and an in vitro transcription was performed, using the RNA Transcription Kit (Stratagene). The RNA concentration was measured photometrically after DNase I digestion, phenol/chloroform treatment, ethanol precipitation, and reconstitution in RNase-free water. Stock solutions of each in vitro-transcribed cRNA containing 1010 molecules/µL were prepared. A special dilutor solution containing 10 mg/L tRNA (Roche Diagnostics) was used for each subsequent dilution step. Stock solutions were stored in liquid nitrogen, and all dilutions were stored at -70 °C.
timp and mmp elisa
The Biotrak TIMP-1, TIMP-2, MMP-2, and MMP-9 human ELISA systems
(Amersham-Pharmacia) were used to determine TIMP or MMP concentrations
in heparin plasma (TIMP-1, 1:21 dilution) and serum (TIMP-2, 1:4
dilution; MMP-2, 1:50 dilution; MMP-9, 1:11 dilution). The TIMP-1 ELISA
detects both the free and complexed form of the protein. In contrast,
the TIMP-2 ELISA detects only unbound, free TIMP-2. An evaluation of
the assays using samples from healthy volunteers was published recently
(21)(22). Between-assay CVs in this
evaluation were <15% for TIMP-1, 6% for TIMP-2, 12% for
MMP-2, and 10% for MMP-9, respectively. Recovery was nearly 100% in
serum and plasma. The MMP-2 assay recognizes the free precursor of
MMP-2 (proMMP-2) and that complexed with TIMP-2, but not active MMP-2.
The MMP-9 ELISA shows 100% cross-reactivity for proMMP-9 and
proMMP-9/TIMP-1 complex. Little cross-reactivity was described for
active MMP-9 (2.7%).
statistics
The Mann–Whitney U-test was performed to compare
results in patient subgroups. Differences were considered significant
when P values were <0.05. Circulating MMP and TIMP protein
concentrations are given as mean ± SD; because of the limited
number of patients, the RNA data are expressed as mean ± SE.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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. Circulating MMP-2 concentrations in healthy controls were
slightly higher than in patients with CAH (752 ± 152 µg/L vs
649 ± 168 µg/L; P <0.01), but absolute differences
were small and the values showed a wide overlap. In patients with Ci,
circulating MMP-2 concentrations were almost twice as high as in
healthy controls (1322 ± 245 µg/L) and overlap of values was
small (P <0.0001 vs controls and vs CAH).
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Circulating MMP-9 concentrations were lower in patients with CAH than in healthy controls (293 ± 226 µg/L vs 455 ± 185 µg/L; P = 0.001) and were lowest in patients with Ci (140 ± 73 µg/L; P <0.001 vs controls and P <0.005 vs CAH, respectively).
Plasma TIMP-1 concentrations were higher in patients with CAH (335 ± 365 µg/L) and Ci (666 ± 244 µg/L) compared with healthy controls (134 ± 29 µg/L). Values in patients with CAH showed wide variation and overlapped with those observed in healthy controls, as well as with those seen in cirrhotic patients. In contrast, the ranges of values in healthy controls and patients with Ci were different from each other. Comparisons between the groups were statistically significant (P <0.001 for healthy controls vs CAH patients, CAH vs Ci patients, and healthy controls vs Ci patients). Circulating TIMP-2 concentrations showed only small changes between the groups. Values in healthy controls and patients with CAH were not significantly different (45 ± 14 µg/L vs 55 ± 45 µg/L). Mean concentrations in patients with Ci were slightly higher (101 ± 101 µg/L; P <0.01), but only 40% (8 of 20) of the values were outside the health-related reference interval.
gelatinase/inhibitor ratios
To calculate the relative inhibition of the two MMPs, we
calculated the ratio between the circulating concentrations of MMP-2
and -9 and TIMP-1 and -2. The results are shown in Fig. 2
. Significant differences between healthy controls and patients
with CAH were found for the ratios MMP-2/TIMP-1 (5.7 ± 1.1 vs
3.1 ± 1.6; P <0.0001) and MMP-9/TIMP-1 (3.5 ±
1.5 vs 1.7 ± 1.8; P <0.0001). At the same time, only
the MMP-9/TIMP-1 (1.7 ± 1.8 vs 0.2 ± 0.1; P
<0.0001) and the MMP-9/TIMP-2 (7.9 ± 8.9 vs 2.2 ± 2.1;
P <0.0001) ratios were significantly different between
patients with CAH and those with Ci. The MMP-2/TIMP-2 ratio was not
statistically different among all three groups (18.4 ± 6.8 for
the healthy controls, 16.7 ± 9.3 for the patients with CAH, and
22.8 ± 16.7 for the patients with Ci).
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qualitative rt-pcr of gelatinases and TIMPs in blood cells and
liver cells
The expression patterns of MMP-2, MMP-9, TIMP-1, and TIMP-2 in
liver tissues and blood cells were different, as shown in a qualitative
RT-PCR analysis (Fig. 3
). MMP-2 mRNA expression was strongly detectable in liver cells
but below the limit of detection in white blood cells. On the other
hand, MMP-9 mRNA expression was strongly detectable in white blood
cells but barely detectable in liver cells. TIMP-1 and TIMP-2 were
found in both cell preparations.
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quantitative rt-pcr of mmp-9, timp-1, and timp-2 in MNLs and PMLs
The results of a quantitative RT-PCR analysis from peripheral
white blood cells for MMP-9, TIMP-1, and TIMP-2 are shown in Fig. 4
. MMP-2 is not shown because expression was below the detection
limit of our assay.
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MMP-9 mRNA expression in MNLs was increased in patients with CAH compared with healthy controls (4300 ± 2900 vs 460 ± 130 RNA-equivalents/cell). However, because of large variation of the observed values in patients with CAH, this difference did not reach statistical significance.
In PMLs, MMP-9 mRNA expression was not different between CAH patients and controls (5300 ± 1900 vs 5250 ± 1100 RNA-equivalents/cell). In contrast, both TIMP-1 and TIMP-2 expression in MNLs was lower in patients with CAH than in controls (5200 ± 1500 vs 7100 ± 1700 RNA-equivalents/cell, P <0.05 for TIMP-1; and 65 ± 15 vs 150 ± 16 RNA-equivalents/cell, P <0.01 for TIMP-2). Again, no difference was found in the expression of TIMP-1 and TIMP-2 mRNA in the PMLs of both groups (1700 ± 280 in CAH patients vs 2400 ± 620 in healthy controls for TIMP-1, and 50 ± 9 in CAH patients vs 62 ± 14 in healthy controls for TIMP-2).
The MMP-9/TIMP-1 and MMP-9/TIMP-2 mRNA expression in the different
circulating cell populations is shown in Fig. 5
. Significant increases were found for both ratios in MNLs
between healthy controls and CAH patients (0.1 ± 0.16 vs 1.2
± 2.1 for MMP-9/TIMP-1; 3.1 ± 4.7 vs 82 ± 151 for
MMP-9/TIMP-2). The relative expression of MMP-9 and both TIMPs in PMLs
did not differ between controls and patients with CAH.
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correlation between different MMPs, TIMPs, and their ratios and
histologic activity
Correlation analyses between the different MMP and TIMP RNA and
protein concentrations measured in our study and the histological
grading and staging of liver biopsies taken at the same time as the
blood samples were performed. Plasma TIMP-1 concentrations
(r = 0.61; P <0.001) as well as the
serum/plasma MMP-2/TIMP-1 ratio (r = -0.44;
P <0.01) correlated with the inflammatory activity.
However, only the circulating MMP-2/TIMP-1 ratio (r =
-0.38; P = 0.03) showed a weak correlation to the
degree of liver fibrosis. Circulating concentrations of MMPs and TIMPs
did not correlate with mRNA expression in MNLs and PMLs.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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The values of all measured proMMPs and TIMPs in the different groups (controls; patients with chronic hepatitis C, and patients with Ci) showed substantial overlap, and only the circulating TIMP-1 concentrations showed a correlation to the inflammatory activity quantified in liver biopsies (14). Such a correlation between serum TIMP-1 values and inflammatory activity has also been found by other groups (2)(7)(8)(25).
In contrast, none of the MMPs and TIMPs measured in this study showed a significant correlation to the extent of fibrosis in the biopsy, irrespective of significant differences in mean values between the groups. Others have found a significant correlation between circulating TIMP-1 and the degree of fibrosis in CAH patients, but the reported correlation coefficients were low (r between 0.30 and 0.40) (2)(7). In our study, the coefficient was 0.31, but the correlation did not reach statistical significance. TIMP-2 also correlated to fibrosis in patients with chronic hepatitis C in a study by Walsh et al. (8), who at the same time found no correlation between fibrosis and MMP-2. On the other hand, Kasahara et al. (2) reported a weak correlation (r = 0.26) between fibrosis and MMP-2.
Therefore, alterations in circulating TIMP-1 concentrations and their correlation to inflammatory activity seem fairly well established, whereas correlations between MMPs, other TIMPs, and histologic changes are found less consistently. All groups found substantial overlap between different patient groups and disease stages (2)(7)(8), and no firm correlation has hitherto been demonstrated for any of the metalloproteinases or TIMPs and fibroproliferative activity.
Looking at the cellular origin of the measured MMPs and TIMPs, we found that MMP-2 mRNA was abundant in liver tissue but could not be detected by RT-PCR and agarose gel electrophoresis in white blood cells, neither in MNLs nor in PMLs. In contrast, MMP-9 was readily detectable in white blood cells but could hardly be detected in liver tissue, where it is localized in Kupffer cells (26)(27) and has been found mainly in patients with hepatocellular carcinoma (28). Both TIMP-1 and TIMP-2 were found in liver and in white blood cells. In an earlier study, we were able to show that the TIMP-1 content in liver tissue is much higher than that of TIMP-2 (1).
It is well known that both MMPs and TIMPs are produced in circulating white blood cells (29)(30). Our results show that the mRNA for MMP-9, TIMP-1, and TIMP-2 can be detected in both MNLs and PMLs. We also were able to quantify the mRNA expression of these proteins, showing that expression of MMP-9 was increased in MNLs of some patients with chronic hepatitis compared with healthy controls. In contrast, expression of both TIMP-1 and TIMP-2 mRNA declined in MNLs of patients with hepatitis C. In PMLs of healthy controls and patients with chronic hepatitis, there was no difference in the expression of all three proteins. No correlation was found between the changes in mRNA content of MNLs and the alterations of the circulating concentrations of the corresponding proteins. However, this may in part reflect limitations of the available assays. Because the assays for MMPs do not detect the active protease, this might obscure a correlation, although active proteases constitute only a small portion of the total amount of these enzymes. More importantly, because the TIMP-2 assay does not detect complexed TIMP-2, it is impossible to determine a correlation between total TIMP-2 and cellular mRNA expression. Nevertheless, no correlation could be found between changes in mRNA expression of the individual proteins and histological inflammatory activity or the extent of fibrosis. Therefore, we suggest that alterations in the circulating protein concentrations seen in liver disease are not derived mainly from blood cells and that expression of MMPs and TIMPs in these cells is influenced by factors other than liver damage as such. The relationship between altered MMP and TIMP expression in MNLs and chronic liver disease may be mediated by several factors, such as cytokine activation, viral load, or hypersplenism (30)(31). In addition, it is possible that alterations in the composition of the MNL subpopulation may contribute to the observed differences in RNA-equivalents per cell.
Our study addresses potential alterations in matrix degradation contributing to enhanced matrix deposition. Therefore, we also calculated the ratios between the MMPs and TIMPs measured in this study. Clear changes of the MMP-2/TIMP-1 and the MMP-9/TIMP-1 ratios in serum and plasma became evident between controls, patients with chronic hepatitis, and patients with Ci, whereas neither the MMP-2/TIMP-2 nor the MMP-9/TIMP-2 ratio showed relevant changes. The decline in both the MMP-2/TIMP-1 and the MMP-9/TIMP-1 ratios are largely attributable to the increases in circulating TIMP concentrations. When correlating the calculated ratios with histological data, we found that the MMP-2/TIMP-1 ratio significantly correlates to both inflammatory activity and the extent of fibrosis, with r values of -0.44 and -0.38, respectively.
The ratio between MMP-2 and TIMP-1 has been evaluated before. Kasahara et al. (2) reported that in patients receiving interferon therapy for chronic hepatitis C, this ratio was correlated to interferon response. The lowest values were found in sustained responders, the highest values were found in non-responders, and transient responders showed intermediate values. It is known that interferon response is better in patients with low inflammatory activity and little fibrosis. Therefore, our results and those of the Japanese group are in accordance, although in the study by Kasahara et al. (2), no direct correlation between histology and the MMP-2/TIMP-1 ratio was reported.
In conclusion, our study demonstrates that in patients with chronic hepatitis C, alterations in the expression of MMP-9, TIMP-1, and TIMP-2 in peripheral blood cells are observed and are likely to be induced by the inflammatory process. However, these alterations in expression do not explain the changes in circulating protein concentrations and do not mirror the progression of the disease in the liver. Changes of the circulating MMP and TIMP concentrations correlate poorly to inflammatory activity and fibrosis in the liver. Only the MMP-2/TIMP-1 ratio, which reflects an increasing dysbalance toward the TIMP-1 concentration, correlates to both inflammatory activity and extent of fibrosis. Future prospective studies must clarify the value of the MMP-2/TIMP-1 ratio as a serum marker for disease progression and prognosis in patients with viral hepatitis and other chronic liver diseases.
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Acknowledgments |
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Footnotes |
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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and TGF-ß1. J Hepatol 1999;30:48-60.
[ISI][Medline]
[Order article via Infotrieve]
and IL-1ß selectively induce expression of 92-kDa gelatinase by human macrophages. J Immunol 1996;157:4159-4165.
[Abstract]
, granulocyte-macrophage CSF, and IL-1ß through prostaglandin-dependent and -independent mechanisms. J Immunol 1998;161:3071-3076.
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) and SD
(bars) for patients and controls are given. Values shown
above horizontal lines are P values for
differences between the groups indicated.
