الفهرس 
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Abstract
Hepatitis C virus (HCV) represents a viral pandemic; it is estimated that about 170 million people worldwide are living with HCV infection. Schistosomiasis is a chronic and debilitating parasitic disease, hepatic schistosomiasis is endemic in rural areas in Egypt. Liver fibrosis and cirrhosis represent the final common pathway of virtually all chronic liver diseases resulting in liver failure, portal hypertension and increased risk of liver cancer.
Chronic liver diseases are accompanied by changes in the pathways regulating apoptosis and extra-cellular matrix deposition. An essential step in the progression of hepatic fibrogenesis is the degradation of normal liver extracellular matrix (ECM), mediated by increased expression of proteolytic enzymes, such as matrix metalloproteinases (MMPs).
Interstitial collagenase (MMP-1) has an important role in promotion of cell migration and matrix degradation as well as in inflammatory and proliferative cell processes. The tissue inhibitors of matrix metalloproteinases (TIMP) family of endogenous proteins (which includes four protease inhibitors: TIMP-1, TIMP-2, TIMP-3 and TIMP-4) regulates the activity of MMPs. TIMPs play a major role in the fine balance in cell degradation under routine physiological control and in pathology. Dysregulation in the levels and control of MMPs can lead to pathological processes.
Apoptosis is a highly regulated, energy-dependent suicide program, whereby the cell activates a signaling cascade that leads to cell death. It plays important roles in numerous physiological events, as well as many pathological conditions. Caspases are aspartate-specific cysteine proteases which are essential for the initiation and execution of apoptosis. They can be divided functionally into initiator and effector caspases. Caspase 3 is an effector caspase that functions as a central regulator of apoptosis.
Matrix metalloproteinases (MMPs) are involved in the acute phase of liver injury as well as during chronic hepatic wound healing and fibrogenesis and may contribute to the inflammatory and fibrogenic response to many stimuli, including viral proteins. Matrix degradation and MMP expression occur even in advanced cirrhosis, but their activity is held in check by TIMPs. Advanced fibrosis is characterized by an accumulation of ECM rich in fibrillar collagens (predominantly collagen I and collagen III), resulting from both increased synthesis and decreased degradation. So fibrosis occurs when the balance between TIMPs and MMPs tips in favor of TIMPs. While in recovery, expression of TIMPs decreases rapidly while matrix degrading metalloproteinases continue to be expressed, resulting in increased collagenase activity and consequent matrix degradation within the liver.
During progressive liver injury, when hepatic stellate cells are activated, their apoptosis is inhibited. When the injurious stimulus is withdrawn and remodeling of matrix is required, the activated stellate cells undergo apoptosis, which facilitates the remodeling process by removing the major cellular source of collagen and TIMPs. Therefore, manipulating matrix degradation or enhancing hepatic stellate cell apoptosis might be expected to reduce fibrosis and promote a return to normal liver architecture. Studies in this area are currently limited to experimental models but
show promise that liver fibrosis can be attenuated by manipulating the TIMP-MMP balance and enhancing hepatic stellate cell apoptosis.
The aim of the present work was to evaluate the levels of serum matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1), and caspase 3 in patients with pure hepatitis C infection, mixed hepatitis C infection and hepatic schistosomiasis, and pure hepatic schistosomiasis.
The present study included eighty two subjects; 25 apparently healthy volunteers (group I), and 57 patients (group II). The patients group was further subdivided into; 22 patients with pure hepatitis C infection (group Ha), 25 patients with mixed hepatitis C infection and hepatic schistosomiasis (group lib), and finally 10 patients with pure hepatic schistosomiasis (group lie).
All the studied groups were subjected to full clinical examination with special stress on history of viral hepatitis and schistosomal infection. Also abdominal ultrasonography was done to all subjects. Patients were classified according to Child- Pugh score depending on clinical assessment and quantification of encephalopathy and ascites as well as laboratory measurements of albumin, bilirubin, and prothrombin activity.
Some liver function tests were done to the studied groups including; total protein, albumin, prothrombin activity, total and direct bilirubin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and gamma glutamyl transferase. There was a significant difference in these parameters in the whole patients group (group II) when compared to their corresponding values in the control group (group I). Also haemoglobin concentrations as well as the count of platelets, red blood cells and white blood cells were determined to all studied subjects. These parameters were significantly decreased in the whole patients group as well as its subgroups (groups II, Ha, lib, and lie) when compared to the control group.
Matrix metalloproteinase-1 level was significantly increased in the whole patients group, and patients with pure hepatitis C infection (groups II, and Ha) when compared to the control group (group I). Also MMP-1 was significantly increased in patients with pure hepatitis C infection (group Ha) when compared to patients with hepatic schistosomiasis (group lie).
Tissue inhibitor of metalloproteinases-1 level was significantly increased in the whole patients group as well as its subgroups (groups II, Ha, lib, and lie) when compared to the control group (group I). Also TIMP-1 was significantly increased in patients with pure hepatitis C infection (group Ha) when compared to patients with hepatic schistosomiasis (group lie) and it was significantly increased in patients with mixed hepatitis C infection and hepatic schistosomiasis (group lib) when compared to patients with hepatic schistosomiasis (group lie).
Although serum aminotransferases show significant increase in the whole patients group when compared to the control group, 38 patients (81%) in groups Ila and lib had normal values of aminotransferases Interestingly, 84% of these patients had high values of TIMP-1 (higher than the cut-off value).
A positive correlation was found between MMP-1 and TIMP-1 in the whole patients group (group II), and in patients with pure hepatitis C (group Ha) . Also there was a significant positive correlation between TIMP-1 and Child-Pugh score in the whole patients group and in patients with mixed hepatitis C infection and hepatic schistosomiasis (group II, and lib).
There was no significant difference in the level of caspase-3 between the whole patients group and the control group, however it was significantly increased in patients with pure hepatitis C infection (group Ha) when compared to patients with mixed hepatitis C infection and hepatic schistosomiasis (group lib).
The equilibrium between MMP-1 and TIMP-1 was maintained between the different groups of the present study, evidenced by the absence of any significant difference between their ratio in the studied groups. On the other hand, the ratios between MMP-1/caspase-3 and TIMP-1/caspase-3 increased significantly in both the whole patients group and in patients with mixed hepatitis C infection and hepatic schistosomiasis (group II, and lib) when compared to the control group (group I). While these ratios did not show significant difference in each of patients with pure hepatitis C infection or pure hepatic schistosomiasis when compared to the control group, although showing tendencies for higher values.
from the present study the following could be concluded:
1- The significant increase of serum TIMP-1 in the whole patients group as well as its subgroups when compared to the control group reflects its role in promoting liver fibrogenesis and progression of hepatic insult. This is also clear from the significant positive correlation found between TIMP-1 and Child-Pugh score. This points to its role in detecting patients with liver cirrhosis.
2- The high values of serum TIMP-1 in patients with normal transaminases may reflect the role of regular determination of TIMP-1 as an indicator of increasing fibrosis and the development of cirrhosis.
3- The significant increase of serum MMP-1 in the whole patients group and in patients with pure hepatitis C infection when compared to the control group despite the increase in serum TIMP-1 denotes that TIMP-1 increases in a trial to alleviate the adverse effects of the increased MMP-1. This is further confirmed by the positive correlation found between MMP-1 and TIMP-1 in this group of patients.
4- The significant increase in both MMP-1/Caspase3 ratio and TIMP1/Caspase3 ratio in the whole patient group when compared to the control group denotes that adding caspase3 to the MMP-1/TIMP-1 system assessment may enforce this ratio by evaluating one important effector in the apoptotic machinery and combining its effect with the state of matrix degradation.
RECOMMENDATIONS
1- The use of TIMP-1 in evaluating HCV patients especially those with normal aminotransferase levels.
2- Correlating liver biopsy in HCV patients with MMP-1, TIMP-1 and caspase-3.
3- Assessment of MMP-1, TIMP-1 and caspase-3 as prognostic tools in treatment of HCV.
4- Evaluation of gene polymorphism of MMP-1, TIMP-1 and caspase-3 to identify causes of progression of HCV fibrosis to cirrhosis.
5- The study of more MMPs and apoptotic markers in relation to HCV, and comparing the results with liver biopsy.