Matrix metalloproteinase (MMP)-2, MMP-7, and tissue inhibitor of metalloproteinase-1 are closely related to the fibroproliferative process in the liver during chronic hepatitis C

Enzymes of Fibrosis in Chronic Liver Disease

Introduction: Liver fibrosis has been extensively studied at the cellular and molecular level, but very few data exist on the final enzymatic stages of collagen synthesis (prolyl hydroxylase, PH) and degradation (matrix metalloproteinases, MMPs), particularly in primary biliary cholangitis (PBC). Aim: We studied enzyme activities in liver tissue from patients with chronic liver diseases and compared them to normal livers. Patients: Eighteen patients with PBC of early and late stages (Ludwig’s classification) and seven on treatment with ursodeoxycholate (UDCA) were studied and compared to 34 patients with alcoholic liver disease (ALD), 25 patients with chronic viral liver disease and five normal biopsies. Sera were available from a total of 140 patients. Methods: The tritiated water released from the tritiated proline was measured in PH assessment. 14C intact and heat-denatured collagen substrates were used to measure collagenase and gelatinases, respectively. 3H Elastin was the substrate for elastase. In serum, ELISAs were used for MMP-1, TIMP-1, and TIMP-2 measurements while MMP-2 and MMP-9 were estimated by zymography. Results: PH was significantly increased in early and late PBC. Collagenase was reduced only in the late stages (p < 0.01), where the ratio PH/collagenase was increased. UDCA treatment restored values to almost normal. Gelatinases were reduced in late stages (p < 0.05). In contrast to PBC and ALD fibrosis, collagen synthesis is not increased in viral fibrosis. The balance shifted towards collagen deposition due to reduced degradation. Interestingly, gelatinolytic activity is not impaired in ALD. Elastase was similar to controls in all diseases studied. TIMP-1 was reduced in early PBC and viral and alcoholic hepatitis and cirrhosis (p < 0.001). Conclusions: (1) There is evidence that collagen synthesis increases in the early stages of PBC, but the collagenolytic mechanism may compensate for the increased synthesis. (2) In viral disease, fibrosis may be due to decreased degradation rather than increased synthesis. (3) The final biochemical stages of liver fibrosis may be quantitatively different according to underlying etiology.

Mer Tyrosine Kinase (MERTK) modulates liver fibrosis progression and hepatocellular carcinoma development

MerTK is a tyrosine kinase receptor that belongs to the TAM (Tyro3/Axl/Mer) receptor family. It is involved in different processes including cellular proliferation/survival, cellular adhesion/migration, and release of the inflammatory/anti-inflammatory cytokines. Although it is reported that MERTK polymorphisms affect the severity of viral and metabolic liver diseases, being able to influence fibrosis progression and hepatocellular carcinoma development, the mechanisms remain unknown. Methods: using a microarray approach, we evaluated the liver expression of genes involved in fibrogenesis and hepatocarcinogenesis in patient with chronic hepatitis C (CHC), stratified for MERTK genotype and MERTK expression. Results: we found that the rs 4374383 AA homozygosity is associated with lower MERTK expression in CHC patients and that, depending on MERTK genotype, Matrix Metallopeptidase 9 (MMP9), Matrix Metallopeptidase 7 (MMP7), Secreted Frizzled Related Protein 1 (SFRP1) and WNT gene family 11(WNT11) show differential expression in patients with CHC with or without neoplastic progression. Conclusions: our results confirm that MERTK represents a genetic biomarker for progression of liver disease and are suggestive of translational relevance for the study of downstream pathways involved in fibrogenesis and hepatocarcinogenesis.

Alleviation of liver cirrhosis and associated portal-hypertension by Astragalus species in relation to their UPLC-MS/MS metabolic profiles: a mechanistic study

Liver cirrhosis is a late-stage liver disease characterized by excessive fibrous deposition triggering portal-hypertension (PH); the prime restrainer for cirrhosis-related complications. Remedies that can dually oppose hepatic fibrosis and lower PH, may prevent progression into decompensated-cirrhosis. Different Astragalus-species members have shown antifibrotic and diuretic actions with possible subsequent PH reduction. However, A.spinosus and A.trigonus were poorly tested for eliciting these actions. Herein, A.spinosus and A.trigonus roots and aerial parts extracts were subjected to comprehensive metabolic-fingerprinting using UHPLC-MS/MS resulting in 56 identified phytoconstituents, followed by chemometric untargeted analysis that revealed variable metabolic profiles exemplified by different species and organ types. Consequently, tested extracts were in-vivo evaluated for potential antifibrotic/anticirrhotic activity by assessing specific markers. The mechanistic prospective to induce diuresis was investigated by analyzing plasma aldosterone and renal-transporters gene-expression. Serum apelin and dimethylarginine-dimethylaminohydrolase-1 were measured to indicate the overall effect on PH. All extracts amended cirrhosis and PH to varying extents and induced diuresis via different mechanisms. Further, An OPLS model was built to generate a comprehensive metabolic-profiling of A.spinosus and A.trigonus secondary-metabolites providing a chemical-based evidence for their efficacious consistency. In conclusion, A.spinosus and A.trigonus organs comprised myriad pharmacologically-active constituents that act synergistically to ameliorate cirrhosis and associated PH.

Disparate effects of MMP and TIMP modulation on coronary atherosclerosis and associated myocardial fibrosis

Matrix metalloproteinase (MMP) activity is tightly regulated by the endogenous tissue inhibitors (TIMPs), and dysregulated activity contributes to extracellular matrix remodelling. Accordingly, MMP/TIMP balance is associated with atherosclerotic plaque progression and instability, alongside adverse post-infarction cardiac fibrosis and subsequent heart failure. Here, we demonstrate that prolonged high-fat feeding of apolipoprotein (Apo)e-deficient mice triggered the development of unstable coronary artery atherosclerosis alongside evidence of myocardial infarction and progressive sudden death. Accordingly, the contribution of select MMPs and TIMPs to the progression of both interrelated pathologies was examined in Apoe-deficient mice with concomitant deletion of Mmp7, Mmp9, Mmp12, or Timp1 and relevant wild-type controls after 36-weeks high-fat feeding. Mmp7 deficiency increased incidence of sudden death, while Mmp12 deficiency promoted survival, whereas Mmp9 or Timp1 deficiency had no effect. While all mice harboured coronary disease, atherosclerotic burden was reduced in Mmp7-deficient and Mmp12-deficient mice and increased in Timp1-deficient animals, compared to relevant controls. Significant differences in cardiac fibrosis were only observed in Mmp-7-deficient mice and Timp1-deficient animals, which was associated with reduced capillary number. Adopting therapeutic strategies in Apoe-deficient mice, TIMP-2 adenoviral-overexpression or administration (delayed or throughout) of a non-selective MMP inhibitor (RS-130830) had no effect on coronary atherosclerotic burden or cardiac fibrosis. Taken together, our findings emphasise the divergent roles of MMPs on coronary plaque progression and associated post-MI cardiac fibrosis, highlighting the need for selective therapeutic approaches to target unstable atherosclerosis alongside adverse cardiac remodelling while negating detrimental adverse effects on either pathology, with targeting of MMP-12 seeming a suitable target.

Characterization of liver injury induced by a pyrrolizidine alkaloid in rats

BACKGROUND

Pyrrolizidine alkaloids (PAs) are common phytotoxins. PA intoxication is reported to cause severe acute liver damage, typically known as hepatic sinusoidal obstruction syndrome (HSOS), but it remains obscure whether the acute liver damage may progress into chronic liver disease characterized by hepatic fibrosis.

PURPOSE

This study aims to characterize the biochemical markers of liver injury and histological features of regressive and progressive liver fibrosis, and to examine changes in hepatic gene expression that may underpin mechanisms of fibrogenesis in rats induced by retrorsine (RTS), a representative toxic PA.

STUDY DESIGN/METHODS

Rats were gavaged with RTS via two dosing regimens, i.e. a single dose of 40 mg/kg (Group 1) and two doses of 40 mg/kg and 20 mg/kg on day 0 and day 7 (Group 2), respectively. Rats receiving one (Group 3) or two (Group 4) doses of vehicle served as negative controls. The animals were followed for up to 16 weeks by serum biochemical analyses and histological examination, and gene expression assays of liver tissues.

RESULTS

Acute liver injury on day 2 manifested as HSOS, characterized by sinusoidal dilation, endothelial cell damage, and elevated serum alanine aminotransferase activity and bilirubin levels. In Group 1, mild liver fibrosis developed at sinusoids and perisinusoidal space surrounding the central veins at week 1 and 2, and thereafter, all liver injury resolved gradually. In Group 2, liver fibrosis progressed within the 16-week observation period. No apparent liver injury was observed in Groups 3 and 4. Compared with negative control groups, RTS induced myofibroblastic activation, TGF-β1 signaling, and changes in expression of matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1). These dynamic changes differed in Groups 1 and 2, corresponding with the regression and progression of liver fibrosis, respectively, in these groups.

CONCLUSION

This study has provided in-vivo proof of concept that "one hit" and "two hits" of RTS lead to acute resolving liver injury and chronic progressive liver fibrosis, respectively. These animal models may serve as powerful tools for studying RTS toxicology and related preventive and therapeutic strategies and as positive controls for studying other PA- and non-PA-induced liver injury.

Molecular Crosstalk between the Hepatitis C Virus and the Extracellular Matrix in Liver Fibrogenesis and Early Carcinogenesis

Simple Summary

In the era of direct-acting antivirals against the hepatitis C virus (HCV), curing chronic hepatitis C has become a reality. However, while replicating chronically, HCV creates a peculiar state of inflammation and oxidative stress in the infected liver, which fuels DNA damage at the onset of HCV-induced hepatocellular carcinoma (HCC). This cancer, the second leading cause of death by cancer, remains of bad prognosis when diagnosed. This review aims to decipher how HCV durably alters elements of the extracellular matrix that compose the liver microenvironment, directly through its viral proteins or indirectly through the induction of cytokine secretion, thereby leading to liver fibrosis, cirrhosis, and, ultimately, HCC.

Abstract

Chronic infection by the hepatitis C virus (HCV) is a major cause of liver diseases, predisposing to fibrosis and hepatocellular carcinoma. Liver fibrosis is characterized by an overly abundant accumulation of components of the hepatic extracellular matrix, such as collagen and elastin, with consequences on the properties of this microenvironment and cancer initiation and growth. This review will provide an update on mechanistic concepts of HCV-related liver fibrosis/cirrhosis and early stages of carcinogenesis, with a dissection of the molecular details of the crosstalk during disease progression between hepatocytes, the extracellular matrix, and hepatic stellate cells.

Strategies Targeting the Innate Immune Response for the Treatment of Hepatitis C Virus-Associated Liver Fibrosis

Direct-acting antivirals eliminate hepatitis C virus (HCV) in more than 95% of treated individuals and may abolish liver injury, arrest fibrogenesis, and reverse fibrosis and cirrhosis. However, liver regeneration is usually a slow process that is less effective in the late stages of fibrosis. What is more, fibrogenesis may prevail in patients with advanced cirrhosis, where it can progress to liver failure and hepatocellular carcinoma. Therefore, the development of antifibrotic drugs that halt and reverse fibrosis progression is urgently needed. Fibrosis occurs due to the repair process of damaged hepatic tissue, which eventually leads to scarring. The innate immune response against HCV is essential in the initiation and progression of liver fibrosis. HCV-infected hepatocytes and liver macrophages secrete proinflammatory cytokines and chemokines that promote the activation and differentiation of hepatic stellate cells (HSCs) to myofibroblasts that produce extracellular matrix (ECM) components. Prolonged ECM production by myofibroblasts due to chronic inflammation is essential to the development of fibrosis. While no antifibrotic therapy is approved to date, several drugs are being tested in phase 2 and phase 3 trials with promising results. This review discusses current state-of-the-art knowledge on treatments targeting the innate immune system to revert chronic hepatitis C-associated liver fibrosis. Agents that cause liver damage may vary (alcohol, virus infection, etc.), but fibrosis progression shows common patterns among them, including chronic inflammation and immune dysregulation, hepatocyte injury, HSC activation, and excessive ECM deposition. Therefore, mechanisms underlying these processes are promising targets for general antifibrotic therapies.

Liver fibrosis improvement in chronic hepatitis C after direct acting-antivirals is accompanied by reduced profibrogenic biomarkers-a role for MMP-9/TIMP-1

BACKGROUND AND AIMS

Disturbances in matrix metalloproteinases (MMPs) and corresponding tissue inhibitors (TIMPs) contribute to hepatitis C virus (HCV)-induced fibrosis. This study aimed to determine MMP-9/TIMP-1 levels in addition to MMP-2 and -9 activities; correlating with the improvement of liver fibrosis in patients under direct-acting antiviral (DAA) therapy.

METHODS

Clinical and laboratory follow-up were performed before treatment and after 12 weeks post-treatment, referred as sustained viral response (SVR). We evaluated liver function including non-invasive fibrosis measurements; MMP activity by zymography; and MMP-9/TIMP-1 complex, inflammatory and pro-fibrogenic mediators by immunoenzymatic assays.

RESULTS

Cohort included 33 patients (59.5 ± 9.3 years, 60.6% females) whose reached SVR and 11 control-paired subjects (42.5 ± 15 years, 54.5% females). Before treatment, HCV patients presented higher MMP-9/TIMP-1 levels (P < 0.05) when compared to controls, and the highest values were observed in patients with fibrosis (P < 0.05). In addition, MMP-9/TIMP-1 levels were significantly reduced after DAA therapy (P < 0.0001) and were associated with profibrogenic biomarkers. No differences were observed for MMP-2 and -9 activities; however, these biomarkers were significantly associated with inflammatory mediators.

CONCLUSION

Our data suggest that MMP-9/TIMP-1 complex can be a promising biomarker of active fibrogenesis, being able to identify the interruption of fibrosis progression after HCV eradication.

Noninvasive Assessment of Liver Fibrosis: Current and Future Clinical and Molecular Perspectives

Liver fibrosis is one of the risk factors for hepatocellular carcinoma (HCC) development. The staging of liver fibrosis can be evaluated only via a liver biopsy, which is an invasive procedure. Noninvasive methods for the diagnosis of liver fibrosis can be divided into morphological tests such as elastography and serum biochemical tests. Transient elastography is reported to have excellent performance in the diagnosis of liver fibrosis and has been accepted as a useful tool for the prediction of HCC development and other clinical outcomes. Two-dimensional shear wave elastography is a new technique and provides a real-time stiffness image. Serum fibrosis markers have been studied based on the mechanism of fibrogenesis and fibrolysis. In the healthy liver, homeostasis of the extracellular matrix is maintained directly by enzymes called matrix metalloproteinases (MMPs) and their specific inhibitors, tissue inhibitors of metalloproteinases (TIMPs). MMPs and TIMPs could be useful serum biomarkers for liver fibrosis and promising candidates for the treatment of liver fibrosis. Further studies are required to establish liver fibrosis-specific markers based on further clinical and molecular research. In this review, we summarize noninvasive fibrosis tests and molecular mechanism of liver fibrosis in current daily clinical practice.

The Many Faces of Matrix Metalloproteinase-7 in Kidney Diseases

Matrix metalloproteinase-7 (MMP-7) is a secreted zinc-dependent endopeptidase that is implicated in regulating kidney homeostasis and diseases. MMP-7 is produced as an inactive zymogen, and proteolytic cleavage is required for its activation. MMP-7 is barely expressed in normal adult kidney but upregulated in acute kidney injury (AKI) and chronic kidney disease (CKD). The expression of MMP-7 is transcriptionally regulated by Wnt/β-catenin and other cues. As a secreted protein, MMP-7 is present and increased in the urine of patients, and its levels serve as a noninvasive biomarker for predicting AKI prognosis and monitoring CKD progression. Apart from degrading components of the extracellular matrix, MMP-7 also cleaves a wide range of substrates, such as E-cadherin, Fas ligand, and nephrin. As such, it plays an essential role in regulating many cellular processes, such as cell proliferation, apoptosis, epithelial-mesenchymal transition, and podocyte injury. The function of MMP-7 in kidney diseases is complex and context-dependent. It protects against AKI by priming tubular cells for survival and regeneration but promotes kidney fibrosis and CKD progression. MMP-7 also impairs podocyte integrity and induces proteinuria. In this review, we summarized recent advances in our understanding of the regulation, role, and mechanisms of MMP-7 in the pathogenesis of kidney diseases. We also discussed the potential of MMP-7 as a biomarker and therapeutic target in a clinical setting.

Size matters-in vitro behaviour of human fibroblasts on textured silicone surfaces with different pore sizes

Capsular contracture remains a challenge in plastic surgery and represents one of the most common postoperative complications following alloplastic breast reconstruction. The impact of the surface structure of silicone implants on the foreign body reaction and the behaviour of connective tissue-producing cells has already been discussed. The aim of this study was to investigate different pore sizes of silicone surfaces and their influence on human fibroblasts in an in vitro model. Four different textures (no, fine, medium and coarse texture) produced with the salt-loss technique, have been assessed in an in vitro model. Human fibroblasts were seeded onto silicone sheets and evaluated after 1, 4 and 7 days microscopically, with viability assay and gene expression analysis. Comparing the growth behaviour and adhesion of the fibroblasts on the four different textures, a dense cell layer, good adhesion and bridge-building ability of the cells could be observed for the fine and medium texture. Cell number and viability of the cells were increasing during the time course of experiments on every texture. TGFß1 was lowest expressed on the fine and medium texture indicating a trend for decreased fibrotic activity. For silicone surfaces produced with the salt-loss technique, we were able to show an antifibrotic effect of smaller sized pores. These findings underline the hypothesis of a key role of the implant surface and the pore size and pore structure in preventing capsular contracture.

A Bioreactor Technology for Modeling Fibrosis in Human and Rodent Precision-Cut Liver Slices

Precision cut liver slices (PCLSs) retain the structure and cellular composition of the native liver and represent an improved system to study liver fibrosis compared to two-dimensional mono- or co-cultures. The aim of this study was to develop a bioreactor system to increase the healthy life span of PCLSs and model fibrogenesis. PCLSs were generated from normal rat or human liver, or fibrotic rat liver, and cultured in our bioreactor. PCLS function was quantified by albumin enzyme-linked immunosorbent assay (ELISA). Fibrosis was induced in PCLSs by transforming growth factor beta 1 (TGFβ1) and platelet-derived growth factor (PDGFββ) stimulation ± therapy. Fibrosis was assessed by gene expression, picrosirius red, and α-smooth muscle actin staining, hydroxyproline assay, and soluble ELISAs. Bioreactor-cultured PCLSs are viable, maintaining tissue structure, metabolic activity, and stable albumin secretion for up to 6 days under normoxic culture conditions. Conversely, standard static transwell-cultured PCLSs rapidly deteriorate, and albumin secretion is significantly impaired by 48 hours. TGFβ1/PDGFββ stimulation of rat or human PCLSs induced fibrogenic gene expression, release of extracellular matrix proteins, activation of hepatic myofibroblasts, and histological fibrosis. Fibrogenesis slowly progresses over 6 days in cultured fibrotic rat PCLSs without exogenous challenge. Activin receptor-like kinase 5 (Alk5) inhibitor (Alk5i), nintedanib, and obeticholic acid therapy limited fibrogenesis in TGFβ1/PDGFββ-stimulated PCLSs, and Alk5i blunted progression of fibrosis in fibrotic PCLS. Conclusion: We describe a bioreactor technology that maintains functional PCLS cultures for 6 days. Bioreactor-cultured PCLSs can be successfully used to model fibrogenesis and demonstrate efficacy of antifibrotic therapies.

Tyrosine 51 residue of the syndecan-2 extracellular domain is involved in the interaction with and activation of pro-matrix metalloproteinase-7

Although syndecan-2 is known to interact with the matrix metalloproteinase-7 (MMP-7), the details of their interaction were unknown. Our experiments with a series of syndecan-2 extracellular domain deletion mutants show that the interaction is mediated through an interaction of the extracellular domain of syndecan-2 (residues 41 to 60) with the α2 helix-loop-α3 helix in the pro-domain of MMP-7. NMR and molecular docking model show that Glu7 of the α1 helix, Glu32 of the α2 helix, and Gly48 and Ser52 of the α2 helix-loop-α3 helix of the MMP-7 pro-domain form the syndecan-2-binding pocket, which is occupied by the side chain of tyrosine residue 51 (Tyr51) of syndecan-2. Consistent with this notion, the expression of a syndecan-2 mutant in which Tyr51 was changed to Ala diminished the interaction between the syndecan-2 extracellular domain and the pro-domain of MMP-7. Furthermore, HT-29 colon adenocarcinoma cells expressing the interaction-defective mutant exhibited reductions in the cell-surface localization of MMP-7, the processing of pro-MMP-7 into active MMP-7, the MMP-7-mediated extracellular domain shedding of both syndecan-2 and E-cadherin, and syndecan-2-mediated anchorage-independent growth. Collectively, these data strongly suggest that Tyr51 of the syndecan-2 extracellular domain mediates its interaction with and activating processing of pro-MMP-7 and regulates MMP-7-dependent syndecan-2 functions.

"Extracellular matrix remodelling in the liver of rats subjected to dietary choline deprivation and/or thioacetamide administration"

Choline deprivation is a recognized experimental approach to nonalcoholic steatohepatitis, while thioacetamide (TAA)-induced liver fibrosis resembles alcoholic liver fibrogenesis. In order to elucidate the effect of TAA on liver extracellular matrix composition under choline deprivation due to choline-deficient diet (CDD) administration, we evaluated the transcriptional and immunohistochemical (IHC) pattern of major hepatic matrix metalloproteinases (namely, MMP-2, -9) and their tissue inhibitors (TIMP-1, -2) in adult male albino Wistar rats at 30, 60 and 90 days. In the CDD+TAA group, IHC showed an early progressive increase in MMP-2 expression, while MMP-9 initially exhibited a significant increase followed by a gradual decrease; TIMP-1 and TIMP-2 IHC expressions showed gradual increase throughout the experiment. The MMPs-TIMPs regulation at the transcriptional level was found to be increased in all groups throughout the experiment. The increased MMP-2/TIMP-2 and suppressed MMP-9/TIMP-1 ratios in IHC and in real-time polymerase chain reaction (RT-PCR) seemed to correlate with the degree of liver fibrosis. These results support the important role of MMPs and TIMPs in controlling the hepatic pathogenesis and shed more light on the recently described experimental approach to liver disease (steatohepatitis) under the impact of two insults (TAA and CDD).

Dysregulation of fibrosis related genes in HCV induced liver disease

BACKGROUND

Liver fibrosis results from a wound healing response to chronic injury, which leads to excessive matrix deposition. Genome wide association studies have showen transcriptional dysregulation in mild and severe liver fibrosis. Recent studies suggested that genetic markers may be able to define the exact stage of liver fibrosis.

AIM

To define genes or genetic pathways that could serve as markers for staging or as therapeutic targets to halt progression of liver fibrosis.

METHODS

The study was performed on 105 treatment naïve HCV genotype 4 infected patients [F0-F2, n = 56; F3-F4, n = 49] and 16 healthy subjects. The study included PCR array on 84 fibrosis related genes followed by customization of a smaller array consisting of 11 genes that were designed on the bases of results obtained from the larger array. Genes that displayed significant dysregulation at mRNA levels were validated at protein levels.

RESULTS AND DISCUSSION

Two major pathways exhibited high dysregulation in early fibrosis as compared with controls or when compared with late fibrosis, these were the TGFβ - related pathway genes and Matrix - deposition associated genes. Hepatic stellate cell (HSC) activators i.e. TGFβ pathway genes [TGFβ1, 2 and 3, their receptors TGFβR1 and 2, signaling molecules SMAD genes and PDGF growth factors] were considerably over-expressed at transcriptional levels as early as F0, whereas expression of their inhibitor TGIF1 was simultaneously down regulated. Matrix proteins including collagen and MMPs were upregulated in early fibrosis whereas tissue inhibitors TIMPs 1 and 2 began over expression in late fibrosis. Expression at protein levels was concordant with RNA data excluding dysregulation at post transcriptional levels.

CONCLUSION

Since these 2 gene sets are closely interrelated regarding HSC activation and proliferation, we assume that the current findings suggest that they are favorable targets to further search for stage specific markers.

New Concepts on Reversibility and Targeting of Liver Fibrosis; A Review Article

Currently, liver fibrosis and its complications are regarded as critical health problems. With the studies showing the reversible nature of liver fibrogenesis, scientists have focused on understanding the underlying mechanism of this condition in order to develop new therapeutic strategies. Although hepatic stellate cells are known as the primary cells responsible for liver fibrogenesis, studies have shown contributing roles for other cells, pathways, and molecules in the development of fibrosis depending on the etiology of liver fibrosis. Hence, interventions could be directed in the proper way for each type of liver diseases to better address this complication. There are two main approaches in clinical reversion of liver fibrosis; eliminating the underlying insult and targeting the fibrosis process, which have variable clinical importance in the treatment of this disease. In this review, we present recent concepts in molecular pathways of liver fibrosis reversibility and their clinical implications.

The inflammatory response to stress and angiogenesis in liver resection for colorectal liver metastases: a randomized controlled trial comparing open versus laparoscopic approach

BACKGROUND

This study evaluates the surgical stress response following laparoscopic and open liver resection for colorectal liver metastasis (CRLM).

METHODS

Patients with CRLM were prospectively randomized to receive open or laparoscopic liver resection (NCT03131778). Blood samples were drawn preoperatively and 24 h after resection. The serum interleukin-6 (IL-6) and IL-8 levels were measured. Furthermore, the mRNA levels of angiogenesis-related factors (vascular endothelial growth factor [VEGF] and HIF-1) and inflammation-related factors (COX-2 and MMP-9) in both tumor tissue and normal liver parenchyma were detected.

RESULTS

Twenty patients for each arm were included. Size of metastasis, type of resection, and neoadjuvant therapy were comparable between groups. Postoperative stay was shorter in the laparoscopic group. Higher levels of IL-6 were observed after the operation in both open and laparoscopic groups, although no differences in the post-operative levels between the groups was noted. Similarly, there were no significant differences in the mRNA expression of VEGF, HIF-1, MMP-9, and COX-2 between the treatment groups. No differences were observed in terms of overall survival and disease free survival.

CONCLUSIONS

The immunological effects of treatment were similar between the groups. Thus, the laparoscopic approach does not seem to significantly influence the surgical stress and tumor related factors in patients suffering from colorectal liver metastases.

Role of the renin-angiotensin system in hepatic fibrosis and portal hypertension

The renin-angiotensin system (RAS) is an important regulator of cirrhosis and portal hypertension. As hepatic fibrosis progresses, levels of the RAS components angiotensin (Ang) II, Ang-(1-7), angiotensin-converting enzyme (ACE), and Ang II type 1 receptor (AT1R) are increased. The primary effector Ang II regulates vasoconstriction, sodium homoeostasis, fibrosis, cell proliferation, and inflammation in various diseases, including liver cirrhosis, through the ACE/Ang II/AT1R axis in the classical RAS. The ACE2/Ang-(1-7)/Mas receptor and ACE2/Ang-(1-9)/AT2R axes make up the alternative RAS and promote vasodilation, antigrowth, proapoptotic, and anti-inflammatory effects; thus, countering the effects of the classical RAS axis to reduce hepatic fibrogenesis and portal hypertension. Patients with portal hypertension have been treated with RAS antagonists such as ACE inhibitors, Ang receptor blockers, and aldosterone antagonists, with very promising hemodynamic results. In this review, we examine the RAS, its roles in hepatic fibrosis and portal hypertension, and current therapeutic approaches based on the use of RAS antagonists in patients with portal hypertension.

Preventive effects of total saponins of Panax japonicus on fatty liver fibrosis in mice

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is a condition in which excess fat accumulates in the liver of a patient without a history of alcohol abuse. Fatty liver fibrosis, a severe form of NAFLD, is a key step which can be reversed by effective medical intervention. This paper aims to describe the protective role and mechanisms of action of total saponins of Panax japonicus (SPJ) against fatty liver fibrosis in mice. In this study, fatty liver fibrosis was induced by a high-fat (HF) diet combined with intraperitoneal injection of porcine serum.

MATERIAL AND METHODS

The fatty liver fibrosis model was induced by HF diet combined with intraperitoneal injection of porcine serum. The endoplasmic reticulum stress (ERS) response and C/EBP homologous protein (CHOP) and p-Jun N-terminal kinase (JNK)-mediated apoptosis and inflammation were assessed by serum biochemistry, hematoxylin-eosin (H + E), Masson and electronic microscopy staining, Hyp content detection, Western blotting and real time polymerase chain reaction (RT-PCR).

RESULTS

Saponins of Panax japonicus could significantly improve liver function and decrease the lipid level in the serum. The liver steatosis, collagen fibers and inflammatory cell infiltration were significantly improved in the SPJ group according to microscope observation. The RT-PCR analysis revealed that the collagen I (Coll), α smooth muscle actin (α-SMA), tissue inhibitors of MMPs (TIMP), CHOP and GRP78 mRNA expression levels were distinctly weakened by SPJ treatment; and western blotting analysis indicated that the phosphorylated JNK (p-JNK), Coll and 78 kD glucose-regulated protein (GRP78) protein expression levels were significantly alleviated, which might be associated with the inhibition of the ERS response and the CHOP and JNK-mediated apoptosis and inflammation pathway.

CONCLUSIONS

Based on this research, SPJ as a preventive medicine has great potential in prevention of liver fibrosis.

Babao Dan attenuates hepatic fibrosis by inhibiting hepatic stellate cells activation and proliferation via TLR4 signaling pathway

Babao Dan (BBD), a traditional Chinese medicine, has been widely used as a complementary and alternative medicine to treat chronic liver diseases. In this study, we aimed to observe the protective effect of BBD on rat hepatic fibrosis induced by diethylnitrosamine (DEN) and explore it possible mechanism. BBD was administrated while DEN was given. After eight weeks, values of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) indicated that BBD significantly protected liver from damaging by DEN and had no obvious side effect on normal rat livers. Meanwhile, BBD attenuated hepatic inflammation and fibrosis in DEN-induced rat livers through histopathological examination and hepatic hydroxyproline content. Furthermore, we found that BBD inhibited hepatic stellate cells activation and proliferation without altering the concentration of lipopolysaccharide (LPS) in portal vein. In vitro study, serum from BBD treated rats (BBD-serum) could also significantly suppress LPS-induced HSCs activation through TLR4/NF-κB pathway. In addition, BBD-serum also inhibited the proliferation of HSCs by regulating TLR4/ERK pathway. Our study demonstrated that BBD may provide a new therapy strategy of hepatic injury and hepatic fibrosis.

Current Perspectives Regarding Stem Cell-Based Therapy for Liver Cirrhosis

Liver cirrhosis is a major cause of mortality and a common end of various progressive liver diseases. Since the effective treatment is currently limited to liver transplantation, stem cell-based therapy as an alternative has attracted interest due to promising results from preclinical and clinical studies. However, there is still much to be understood regarding the precise mechanisms of action. A number of stem cells from different origins have been employed for hepatic regeneration with different degrees of success. The present review presents a synopsis of stem cell research for the treatment of patients with liver cirrhosis according to the stem cell type. Clinical trials to date are summarized briefly. Finally, issues to be resolved and future perspectives are discussed with regard to clinical applications.

Matrix metalloproteinase functions in hepatic injury and fibrosis

Liver fibrosis is the most common final outcome for chronic liver diseases. The complex pathogenesis includes hepatic parenchymal damage as a result of a persistent noxe, activation and recruitment of immune cells, activation of hepatic stellate cells, and the synthesis of fibrotic extracellular matrix (ECM) components leading to scar formation. Clinical studies and animal models demonstrated that fibrosis can be reversible. In this regard matrix metalloproteinases (MMPs) have been focused as therapeutic targets due to their ability to modulate tissue turnover during fibrogenesis as well as regeneration and, of special interest, due to their influence on cellular behavior like proliferation, gene expression, and apoptosis that, in turn, impact fibrosis and regeneration. The current review aims to summarize and update the knowledge about expression pattern and the central roles of MMPs in hepatic fibrosis.

Current status and future prospects of mesenchymal stem cell therapy for liver fibrosis

Liver fibrosis is the end-stage of many chronic liver diseases and is a significant health threat. The only effective therapy is liver transplantation, which still has many problems, including the lack of donor sources, immunological rejection, and high surgery costs, among others. However, the use of cell therapy is becoming more prevalent, and mesenchymal stem cells (MSCs) seem to be a promising cell type for the treatment of liver fibrosis. MSCs have multiple differentiation abilities, allowing them to migrate directly into injured tissue and differentiate into hepatocyte-like cells. Additionally, MSCs can release various growth factors and cytokines to increase hepatocyte regeneration, regress liver fibrosis, and regulate inflammation and immune responses. In this review, we summarize the current uses of MSC therapies for liver fibrosis and suggest potential future applications.

Novel Role for Matrix Metalloproteinase 9 in Modulation of Cholesterol Metabolism

Background

The development of atherosclerosis is strongly linked to disorders of cholesterol metabolism. Matrix metalloproteinases (MMPs) are dysregulated in patients and animal models with atherosclerosis. Whether systemic MMP activity influences cholesterol metabolism is unknown.

Methods and Results

We examined MMP‐9–deficient (Mmp9^−/−) mice and found them to have abnormal lipid gene transcriptional responses to dietary cholesterol supplementation. As opposed to Mmp9^+/+ (wild‐type) mice, Mmp9^−/− mice failed to decrease the hepatic expression of sterol regulatory element binding protein 2 pathway genes, which control hepatic cholesterol biosynthesis and uptake. Furthermore, Mmp9^−/− mice failed to increase the expression of genes encoding the rate‐limiting enzymes in biliary cholesterol excretion (eg, Cyp7a and Cyp27a). In contrast, MMP‐9 deficiency did not impair intestinal cholesterol absorption, as shown by the ¹⁴C‐cholesterol and ³H‐sitostanol absorption assay. Similar to our earlier study on Mmp2^−/− mice, we observed that Mmp9^−/− mice had elevated plasma secreted phospholipase A₂ activity. Pharmacological inhibition of systemic circulating secreted phospholipase A₂ activity (with varespladib) partially normalized the hepatic transcriptional responses to dietary cholesterol in Mmp9^−/− mice. Functional studies with mice deficient in other MMPs suggested an important role for the MMP system, as a whole, in modulation of cholesterol metabolism.

Conclusions

Our results show that MMP‐9 modulates cholesterol metabolism, at least in part, through a novel MMP‐9–plasma secreted phospholipase A₂ axis that affects the hepatic transcriptional responses to dietary cholesterol. Furthermore, the data suggest that dysregulation of the MMP system can result in metabolic disorder, which could lead to atherosclerosis and coronary heart disease.

Mesenchymal stem cell therapy for liver fibrosis

Currently, the most effective treatment for end-stage liver fibrosis is liver transplantation; however, transplantation is limited by a shortage of donor organs, surgical complications, immunological rejection, and high medical costs. Recently, mesenchymal stem cell (MSC) therapy has been suggested as an effective alternate approach for the treatment of hepatic diseases. MSCs have the potential to differentiate into hepatocytes, and therapeutic value exists in their immune-modulatory properties and secretion of trophic factors, such as growth factors and cytokines. In addition, MSCs can suppress inflammatory responses, reduce hepatocyte apoptosis, increase hepatocyte regeneration, regress liver fibrosis and enhance liver functionality. Despite these advantages, issues remain; MSCs also have fibrogenic potential and the capacity to promote tumor cell growth and oncogenicity. This paper summarizes the properties of MSCs for regenerative medicine and their therapeutic mechanisms and clinical application in the treatment of liver fibrosis. We also present several outstanding risks, including their fibrogenic potential and their capacity to promote pre-existing tumor cell growth and oncogenicity.

Plasma Levels of Matrix Metalloproteinase (MMP)-2, MMP-9 and Tumor Necrosis Factor-α in Chronic Hepatitis C Virus Patients

BACKGROUND

In chronic HCV infection, pathological accumulation of the extracellular matrix is the main feature of liver fibrosis; that indicates the imbalanced rate of increased matrix synthesis to decreased breakdown of connective tissue proteins. Matrix metalloproteinases (MMPs) play a crucial role in remodeling of extracellular matrix. It is known that expression of MMPs is regulated by Tumor necrosis factor (TNF)-α. Also, levels of TNF-α in liver and serum are increased in chronic HCV patient. Accordingly, this study aimed to correlate the plasma levels of MMP-2, MMP-9 and TNF-α in chronic HCV patients with the pathogenesis of the liver.

METHODS

The current study was conducted on 15 fibrotic liver cases with detectable HCV RNA, 10 HCV cirrhotic liver cases, and 15 control subjects of matched age and sex. Plasma MMP-2, MMP-9 and TNF-α were measured by ELISA.

RESULTS

Data revealed that the MMP2, MMP9 and TNF-α levels showed a significant elevation in chronic HCV patients compared to control group (p= 0.001). But, no significant correlation was observed in levels of MMP-2, MMP-9, and TNF-α between fibrotic and cirrhotic cases.

CONCLUSIONS

MMP-2, MMP-9 and TNF-α showed high reproducibility to differentiate chronic HCV patients from control group. On the contrary, MMP-2, MMP-9 and TNF-α were not able to differentiate fibrotic from cirrhotic liver cases. Thus, MMP-2, MMP-9 and TNF-α could not be correlated with the progression of liver disease. Rather they could be used as prognostic markers of liver fibrosis.

Transcriptional profiling of chronic clinical hepatic schistosomiasis japonica indicates reduced metabolism and immune responses

Schistosomiasis is a significant cause of human morbidity and mortality. We performed a genome-wide transcriptional survey of liver biopsies obtained from Chinese patients with chronic schistosomiasis only, or chronic schistosomiasis with a current or past history of viral hepatitis B. Both disease groups were compared with patients with no prior history or indicators of any liver disease. Analysis showed in the main, downregulation in gene expression, particularly those involved in signal transduction via EIF2 signalling and mTOR signalling, as were genes associated with cellular remodelling. Focusing on immune associated pathways, genes were generally downregulated. However, a set of three genes associated with granulocytes, MMP7, CLDN7, CXCL6 were upregulated. Differential gene profiles unique to schistosomiasis included the gene Granulin which was decreased despite being generally considered a marker for liver disease, and IGBP2 which is associated with increased liver size, and was the most upregulated gene in schistosomiasis only patients, all of which presented with hepatomegaly. The unique features of gene expression, in conjunction with previous reports in the murine model of the cellular composition of granulomas, granuloma formation and recovery, provide an increased understanding of the molecular immunopathology and general physiological processes underlying hepatic schistosomiasis.

Gelatinase activities and TIMP-2 serum level in alcohol cirrhosis and chronic pancreatitis

There are some divergent data concerning the role of matrix metalloproteinase (MMP)-2, MMP-9 and tissue inhibitor of MMP (TIMP)-2 in the pathogenesis of alcoholic cirrhosis (AC) and chronic pancreatitis (CP). Our objective was to evaluate the activity of MMP-2, MMP-9 and TIMP-2 serum levels in patients with AC and CP. Twenty-one patients with diagnosis of AC and twenty-two with CP admitted to the outpatient clinic for a control visit were enrolled. All results were compared with age and sex-matched control group (n=19). The sera obtained from venous blood were stored at -70°C for further analysis. Activity of MMP-2 and MMP-9 were evaluated with gelatin zymography, TIMP-2 serum level was analyzed with the usage of ELISA method. A significant decrease of serum MMP-2 activity was noted in sera of AC and CP patients in comparison with control. Activity of MMP-9 was elevated only in CP patients and TIMP-2 serum level was elevated only in AC patients. Decreased activity of MMP-2 in AC patients can contribute to cirrhosis development. The high level of MMP-9 in serum related to CP patients theoretically can exacerbate the inflammatory process within the pancreas.

Effect of Antiadhesion Barrier Solution and Fibrin on Capsular Formation After Silicone Implant Insertion in a White Rat Model

INTRODUCTION

One of the most serious complications of breast reconstruction and augmentation using silicone implants is capsular contracture. Several preventive treatments, including vitamin E, steroids, antibiotics, and cysteinyl leukotriene inhibitors, have been studied, and their clinical effects have been reported. However, the problem of capsular contracture has not yet been completely resolved. This study was performed to compare anti-adhesion barrier solution (AABS) and fibrin in their ability to prevent fibrotic capsule formation and simultaneously evaluated their effect when used in combination by capsular thickness analysis and quantitative analysis of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), and type I collagen within the fibrous capsule.

MATERIALS AND METHODS

This study used female six-week-old Sprague-Dawley rats. Eighty rats were equally subdivided into the four following groups: AABS-treated, fibrin-treated, AABS and fibrin combined-treated, and untreated control groups. Each rat received two silicone chips under the panniculus carnosus muscle layer. The test materials were applied around the silicon chips. Four weeks later, the implantation sites including the skin and muscle were excised to avoid the risk of losing the fibrous capsule around the implants. The capsular thickness was analyzed by Masson's trichrome stain. Quantitative analysis of type I collagen, MMPs, and TIMPs was performed by real-time PCR, Western blot, and zymography.

RESULTS

The mean capsular thickness was 668.10 ± 275.12 μm in the control group, 356.97 ± 112.11 μm in the AABS-treated group, 525.96 ± 130.97 μm in the fibrin-treated group, and 389.24 ± 130.51 μm in the AABS and fibrin combined-treated group. Capsular thickness was significantly decreased in all experimental groups (p < 0.05). Capsular thickness was greater in the fibrin-treated group than in the AABS-treated group (p < 0.05). There was no statistically significant difference in capsular thickness between the AABS and fibrin combined-treated group and the AABS- or fibrin-treated group (p > 0.05). Compared to the control group, the experimental groups had significantly lower expressions of type I collagen and MMP-1 (p < 0.05), but there was no statistically significant difference in expressions of type I collagen and MMP-1 between the AABS-, fibrin-, and AABS and fibrin combined-treated groups (p > 0.05). The expressions of MMP-2 and TIMP-2 were not significantly different between the control and the experimental groups (p > 0.05).

CONCLUSION

AABS is more effective in reducing capsular thickness compared with fibrin treatment in a white rat model.

Bone marrow derived stem cells for the treatment of end-stage liver disease

End-stage disease due to liver cirrhosis is an important cause of death worldwide. Cirrhosis results from progressive, extensive fibrosis and impaired hepatocyte regeneration. The only curative treatment is liver transplantation, but due to the several limitations of this procedure, the interest in alternative therapeutic strategies is increasing. In particular, the potential of bone marrow stem cell (BMSC) therapy in cirrhosis has been explored in different trials. In this article, we evaluate the results of 18 prospective clinical trials, and we provide a descriptive overview of recent advances in the research on hepatic regenerative medicine. The main message from the currently available data in the literature is that BMSC therapy is extremely promising in the context of liver cirrhosis. However, its application should be further explored in randomized, controlled trials with large cohorts and long follow-ups.

Enzyme-linked immunosorbent assay characterization of basal variation and heritability of systemic microfibrillar-associated protein 4

Background

Microfibrillar-associated protein 4 (MFAP4) is a systemic biomarker that is significantly elevated in samples from patients suffering from hepatic cirrhosis. The protein is generally localized to elastic fibers and other connective tissue fibers in the extracellular matrix (ECM), and variation in systemic MFAP4 (sMFAP4) has the potential to reflect diverse diseases with increased ECM turnover. Here, we aimed to validate an enzyme-linked immunosorbent assay (ELISA) for the measurement of sMFAP4 with an emphasis on the robustness of the assay. Moreover, we aimed to determine confounders influencing the basal sMFAP4 variability and the genetic contribution to the basal variation.

Methods

The sandwich ELISA was based on two monoclonal anti-MFAP4 antibodies and was optimized and calibrated with a standard of recombinant MFAP4. The importance of pre-analytical sample handling was evaluated regarding sample tube type, time, and temperature conditions. The mean value structure and variance structure was determined in a twin cohort including 1,417 Danish twins (age 18-67 years) by mixed-effect linear regression modeling.

Results

The practical working range of the sandwich ELISA was estimated to be 4-75 U/ml. The maximum intra- and inter-assay variation was estimated to be 8.7% and 6.6%, respectively. Sample handling and processing appeared to influence MFAP4 measurements only marginally. The average concentration of sMFAP4 in the serum was 18.9 ± 8.4 (SD) U/ml in the twin cohort (95% CI: 18.5-19.4, median sMFAP4 17.3 U/ml). The mean structure model was demonstrated to include waist-hip ratio, age, and cigarette smoking status in interactions with gender. A relatively low heritability of h² = 0.24 was found after applying a model including additive genetic factors and shared and non-shared environmental factors.

Conclusions

The described ELISA provides robust measures of the liver fibrosis marker sMFAP4. The low heritability and the relatively limited basal variation suggest that increased sMFAP4 reflects disease-induced processes.

Protective effect of the herbal medicine Gan‑fu‑kang against carbon tetrachloride‑induced liver fibrosis in rats

The aim of the present study was to investigate the effect of a herbal medicine formula, Gan-fu-kang (GFK), on the treatment of liver fibrosis in rats and the mechanisms via which it exerts its effect. Liver fibrosis was induced in rats by subcutaneous injection of carbon tetrachloride (CCl4) at 0.5 mg/kg body weight, twice a week for 8 weeks. The rats were randomly selected to receive saline or GFK at 31.25, 312.5 or 3,125 mg/kg body weight/day between weeks 9 and 20. An additional group of rats without CCl4 injection was used as the baseline. In the liver fibrosis model rats, an increase in plasma liver enzymes, fibrotic markers in serum and liver fibrosis, production of α-smooth muscle actin, matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-1, synthesis of collagen and activation of the Wnt/β-catenin signaling pathway were observed. GFK administration was found to significantly reduce these changes. Results of this study demonstrate that GFK has a protective and therapeutic effect on liver fibrosis induced by CCl4, which may be associated with its inhibitory activity on HSC proliferation and collagen synthesis, effectively downregulating Wnt/β-catenin signaling.

The molecular mechanism of hypertrophic scar

Hypertrophic scar (HTS) is a dermal form of fibroproliferative disorder which often develops after thermal or traumatic injury to the deep regions of the skin and is characterized by excessive deposition and alterations in morphology of collagen and other extracellular matrix (ECM) proteins. HTS are cosmetically disfiguring and can cause functional problems that often recur despite surgical attempts to remove or improve the scars. In this review, the roles of various fibrotic and anti-fibrotic molecules are discussed in order to improve our understanding of the molecular mechanism of the pathogenesis of HTS. These molecules include growth factors, cytokines, ECM molecules, and proteolytic enzymes. By exploring the mechanisms of this form of dermal fibrosis, we seek to provide some insight into this form of dermal fibrosis that may allow clinicians to improve treatment and prevention in the future.

Changes in Activities of MMP in Alcohol and Thermally Oxidized Sunflower Oil-Induced Liver Damage: NAC Antioxidant Therapy

Liver fibrosis is the result of imbalance between extracellular matrix (ECM) synthesis and breakdown. Ethanol-induced increase in redox state is a sign of major change in hepatic metabolism and this inhibits tricarboxylic acid cycle activity and, fatty acid oxidation and increases fatty acid uptake, thus predisposing fatty liver. Fibrotic changes induced by alcohol are provoked by diets rich in PUFA. Heating of oils rich in PUFA produces toxic volatile and nonvolatile compounds, which aggravate liver damage. Hepatotoxicity was induced in male Wistar rats by administering alcohol (20%) and thermally oxidized sunflower oil (Delta PUFA) (15%). When N-acetyl cyteine (NAC) (150 mg/kg body weight), an ROS scavenger, was administered, there was a reversal of liver damage, which was demonstrated biochemically. Matrix metalloproteinases (MMPs), being potential biochemical indicators of fibroproliferation, were estimated in the present study, which were found to be altered in alcohol, Delta PUFA, and alcohol + Delta PUFA. The altered activities of MMPs in these groups were effectively modulated by treatment with NAC. Thus, in this study, NAC was found to modulate the effect of alcohol and Delta PUFA-induced liver damage.

Didanosine (ddI) associates with increased liver fibrosis in adult HIV-HCV coinfected patients

The role of exposure to antiretrovirals (ARV) and serum matrix metalloproteases (MMPs) on liver fibrosis (LF) progression in human immunodeficiency virus (HIV) mono or HIV- hepatitis C virus (HCV) coinfection is unclear. Thus, 213 Caucasian adult HIV-infected patients were studied, 111 of whom had HCV-coinfection and 68 were HCV-monoinfected. Patients with ethanol consumption >50 g/day, hepatitis B coinfection, non-infective liver diseases or HAART adherence <75% were excluded. LF was assessed by transient elastometry (TE, Fibroscan). Serum levels of MMPs (MMP -1,-2,-3,-8,-9,-10 and -13) and their tissue inhibitors (TIMP-1,-2 and -4) were measured by ELISA microarrays. Associations with LF were statistically analysed. Protease inhibitors, usually administered to patients with advanced LF were excluded from the analysis. Increased LF was significantly associated with d4T (P = 0.006) and didanosine (ddI) use (P = 0.007), months on d4T (P = 0.001) and on ARV (P = 0.025), duration of HIV (P < 0.0001) and HCV infections (P < 0.0001), higher HIV (P = 0.03) and HCV loads (P < 0.0001), presence of lipodystrophy (P = 0.02), male gender (P = 0.02), older age (P = 0.04), low nadir (P = 0.02) and current CD4(+) T-cells (P < 0.0001), low gain of CD4(+) T-cells after HAART (P = 0.01) and higher MMP-2 (P = 0.02) and TIMP-2 serum levels (P = 0.02). By logistic regression the only variables significantly associated with increased LF were: use of ddI (OR 8.77, 95% CI: 2.36-32.26; P = 0.005), male gender (OR 7.75, 95% CI: 2.33-25.64, P = 0.0008), HCV viral load (in log) (OR 3.53, 95% CI: 2.16-5.77; P < 0.0001) and age (in years) (OR 1.21, 95% CI: 1.09-1.34, P = 0.0003). We conclude that only higher HCV viral load, older age, male gender, and use of ddI associated independently with increased LF in our study.

Hepatoprotection of silymarin against thioacetamide-induced chronic liver fibrosis

BACKGROUND

Liver fibrosis is chronic liver damage usually caused by alcohol, viruses or other toxins and is characterised by an excessive accumulation of extracellular matrix proteins such as collagen. The aim of this study was to establish an animal model of chronic liver damage and investigate molecular mechanisms of silymarin hepatoprotective effects.

RESULTS

Thioacetamide (TAA; 100 mg kg(-1) intraperitoneal (i.p.) injection three times weekly) effectively induced chronic liver fibrosis in male ICR mice. Then 24 ICR mice were randomly divided into four groups: (1) saline (i.p.) + water (gavage); (2) saline (i.p.) + 150 mg kg(-1) silymarin (gavage); (3) 100 mg kg(-1) TAA (i.p.) + water (gavage); (4) 100 mg kg(-1) TAA (i.p.) + 150 mg kg(-1) silymarin (gavage). Eight weeks of TAA treatment resulted in lower body weight, serum cholesterol and triglycerides as well as increased liver size, ALT, AST and LDH values (P < 0.05). These TAA-induced effects were attenuated by silymarin (P < 0.05); therefore silymarin also ameliorated TAA-induced liver lesions. Effects of silymarin on TAA-induced chronic liver damage may be attributed to down-regulation of hepatic MMP-2, MMP-13, TIMP-1, TIMP-2, AP-1, KLF6, TGF-β1, α-SMA and COL-α1.

CONCLUSION

A mouse model of chronic liver fibrosis was successfully established by injecting 100 mg kg(-1) TAA three times weekly in male ICR mice. Meanwhile, silymarin showed hepatoprotection against TAA-induced damage.

The decrease of serum MMP-2 activity corresponds to alcoholic cirrhosis stage

Because of numerous limitations for liver biopsy, a noninvasive marker of liver cirrhosis is sought. Promising indicators seem to be matrix metalloproteinases (MMPs) that are responsible for degradation of extracellular matrix. The aim of the study was to evaluate the gelatinase activities (MMP-2 and MMP-9) in patients with different stages of alcoholic cirrhosis. Sixty-seven outpatients who presented various stages of alcoholic cirrhosis according to Child-Turcotte-Pugh criteria and 26 healthy control subjects were enrolled. Blood samples were collected for MMP-2 and MMP-9 activities. A significant decrease of serum MMP-2 activity was noted in stages B and C of cirrhosis in comparison with control. Serum MMP-9 activity did not depend on the stage of cirrhosis. The MMP-2 levels, but not those of MMP-9, may be of value in understanding the pathogenesis and progression of alcoholic cirrhosis.

Matrix metalloproteinase-7 as a surrogate marker predicts renal Wnt/β-catenin activity in CKD

A variety of chronic kidney diseases exhibit reactivation of Wnt/β-catenin signaling. In some tissues, β-catenin transcriptionally regulates matrix metalloproteinase-7 (MMP-7), but the association between MMP-7 and Wnt/β-catenin signaling in chronic kidney disease is unknown. Here, in mouse models of both obstructive nephropathy and focal segmental glomerulosclerosis (adriamycin nephropathy), we observed upregulation of MMP-7 mRNA and protein in a time-dependent manner. The pattern and extent of MMP-7 induction were positively associated with Wnt/β-catenin signaling in these models. Activation of β-catenin through ectopic expression of Wnt1 promoted MMP-7 expression in vivo, whereas delivery of the gene encoding the endogenous Wnt antagonist Dickkopf-1 abolished its induction. Levels of MMP-7 protein detected in the urine correlated with renal Wnt/β-catenin activity. Pharmacologic blockade of Wnt/β-catenin signaling by paricalcitol inhibited MMP-7 expression in diseased kidneys and reduced the levels detected in the urine. In vitro, β-catenin activation induced the expression and secretion of MMP-7 and promoted the binding of T cell factor to the MMP-7 promoter in kidney epithelial cells. We also observed higher levels of MMP-7 expression, which correlated with β-catenin, in kidney tissue from patients with various nephropathies. In summary, levels of renal MMP-7 correlate with Wnt/β-catenin activity, and urinary MMP-7 may be a noninvasive biomarker of this profibrotic signaling in the kidney.

Matrilysin (MMP-7) inhibition of BMP-7 induced renal tubular branching morphogenesis suggests a role in the pathogenesis of human renal dysplasia

Congenital renal dysplasia (RD) is a severe form of congenital renal malformation characterized by disruption of normal renal development with cyst formation, reduced or absent nephrons, and impaired renal growth. The authors previously identified that matrilysin (matrix metalloproteinase-7) was overexpressed in a microarray gene expression analysis of human RD compared to normal control kidneys. They now find that active matrilysin gene transcription and protein synthesis occur within dysplastic tubules and epithelial cells lining cysts in human RD by RT-PCR and immunohistochemistry. Similar staining patterns were seen in obstructed kidneys of pouch opossums that show histological features similar to that of human RD. In vitro, matrilysin inhibits formation of branching structures in mIMCD-3 cells stimulated by bone morphogenetic protein-7 (BMP-7) but does not inhibit hepatocyte growth factor-stimulated branching. BMP-7 signaling is essential for normal kidney development, and overexpression of catalytically active matrilysin in human embryonic kidney 293 cells reduces endogenous BMP-7 protein levels and inhibits phosphorylation of BMP-7 SMAD signaling intermediates. These findings suggest that matrilysin expression in RD may be an injury response that disrupts normal nephrogenesis by impairing BMP-7 signaling.

Markers of inflammation and fibrosis in alcoholic hepatitis and viral hepatitis C

High levels of profibrinogenic cytokine transforming factor beta (TGF-β), metalloprotease (MMP2), and tissue inhibitor of matrix metalloprotease 1 (TIMP1) contribute to fibrogenesis in hepatitis C virus (HCV) infection and in alcohol-induced liver disease (ALD). The aim of our study was to correlate noninvasive serum markers in ALD and HCV patients with various degrees of inflammation and fibrosis in their biopsies. Methods. Serum cytokines levels in HCV-infected individuals in the presence or absence of ALD were measured. Student's-t-test with Bonferroni correction determined the significance between the groups. Results. Both tumor-necrosis-factor- (TNF)-α and TGF-β levels increased significantly with the severity of inflammation and fibrosis. TGF-β levels increased significantly in ALD patients versus the HCV patients. Proinflammatory cytokines' responses to viral and/or toxic injury differed with the severity of liver inflammation. A combination of these markers was useful in predicting and diagnosing the stages of inflammation and fibrosis in HCV and ALD. Conclusion. Therapeutic monitoring of TGF-β and metalloproteases provides important insights into fibrosis.

Levels of serum markers of liver inflammation and fibrosis in patients with chronic hepatitis C virus infection according to HIV status and antiretroviral use

Liver disease in patients with chronic hepatitis C virus (HCV) infection has an accelerated course in the presence of human immunodeficiency virus (HIV) coinfection. Some data suggest that HIV suppression achieved with highly active antiretroviral therapy (HAART) ameliorates HCV-related liver disease progression. The aim of this study was to test if there is overexpression of serum markers of liver inflammation and fibrosis in HIV-HCV-coinfected patients and if the effect is counteracted by HAART. In a pilot, cross-sectional, and comparative study serum markers of liver inflammation (CK-18 and HGF) and fibrosis (HGF, MMP-2, and TIMP-1) were measured via ELISA in HIV-infected patients off and on HAART, HCV monoinfected, HIV-HCV coinfected off and on HAART, and controls (10 per group). HIV-HCV-coinfected off HAART patients with low CD4 counts had higher levels of M30, HGF, and MMP-2 than HIV-HCV-coinfected on HAART. HCV coinfection predicted higher levels of MMP-2 [B 65.82 (95% CI 3.86-127.78); p = 0.04], HGF [B 520.22 (95% CI 123.65-916.78); p = 0.01] and M30 [B 128.02 (95%CI 16.39-239.64); p = 0.03]. HAART use was a predictor of lower levels of MMP2 [B -83.18 (95%CI (-146.8) - (-19.52)); p = 0.01] and M30 [B -112.9 (95% CI (-221.3) - (-4.52)); p = 0.04]. Other factors analyzed including alcohol intake ware not associated with the studied markers. In conclusion, serum markers of hepatic inflammation and fibrosis are overexpressed in HIV-HCV-coinfected patients with advanced immunosuppression, while HAART has a "protective" effect.

Increased urinary lipocalin-2 reflects matrix metalloproteinase-9 activity in chronic hepatitis C with hepatic fibrosis

Hepatic fibrosis is characterized by excessive accumulation of extracellular matrix. Matrix metalloproteinases (MMPs) play an important role in the remodeling of the extracellular matrix during hepatic fibrosis. Lipocalin-2 (LCN2) forms complexes with MMP-9 and can be detected in the urine of patients with several types of cancers. The objective of this study was to examine the relationship between urinary LCN2 levels and MMP-9 activity with respect to the stage of liver fibrosis in patients with chronic hepatitis C (CHC), and to assess the utility of urine LCN2 as a non-invasive marker of hepatic fibrosis. Fresh spot urine samples were prospectively collected from forty-two interferon-naive CHC patients who underwent liver biopsy. The stage of hepatic fibrosis was assessed according to the METAVIR fibrosis score; 18 patients had no or mild fibrosis (stages F0 and F1) and 24 patients showed significant fibrosis (stages F2-F4). Immunoblot analyses demonstrated co-migration of urine LCN2 and MMP-9. Gelatin zymography showed that urinary MMP-9/MMP-2 activity ratios were higher in patients with significant fibrosis (F2-F4) than in patients no or mild fibrosis (F0-F1). Urine LCN2 levels which were normalized to urine creatinine concentration (urine LCN2-to-creatinine ratio; ULCR) were higher in F2-F4 patients compared to F0-F1 patients. There was a positive correlation between ULCR and urine MMP-9/MMP-2 activity ratios (r = 0.735). ULCR and AST-to-platelet ratio index were independent predictors of significant fibrosis by multivariate analysis. The present study suggests that urinary LCN2 is a novel marker of hepatic fibrosis by reflecting urine MMP-9 activity in CHC.

Loss of matrix metalloproteinase-2 amplifies murine toxin-induced liver fibrosis by upregulating collagen I expression

BACKGROUND AND AIMS

Matrix metalloproteinase-2 (MMP-2), a type IV collagenase secreted by activated hepatic stellate cells (HSCs), is upregulated in chronic liver disease and is considered a profibrotic mediator due to its proliferative effect on cultured HSCs and ability to degrade normal liver matrix. Although associative studies and cell culture findings suggest that MMP-2 promotes hepatic fibrogenesis, no in vivo model has definitively established a pathologic role for MMP-2 in the development and progression of liver fibrosis. We therefore examined the impact of MMP-2 deficiency on liver fibrosis development during chronic CCl(4) liver injury and explored the effect of MMP-2 deficiency and overexpression on collagen I expression.

METHODS

Following chronic CCl(4) administration, liver fibrosis was analyzed using Sirius Red staining with quantitative morphometry and real-time polymerase chain reaction (PCR) in MMP-2-/- mice and age-matched MMP-2+/+ controls. These studies were complemented by analyses of cultured human stellate cells.

RESULTS

MMP-2-/- mice demonstrated an almost twofold increase in fibrosis which was not secondary to significant differences in hepatocellular injury, HSC activation or type I collagenase activity; however, type I collagen messenger RNA (mRNA) expression was increased threefold in the MMP-2-/- group by real-time PCR. Furthermore, targeted reduction of MMP-2 in cultured HSCs using RNA interference significantly increased collagen I mRNA and protein, while overexpression of MMP-2 resulted in decreased collagen I mRNA.

CONCLUSIONS

These findings suggest that increased MMP-2 during the progression of liver fibrosis may be an important mechanism for inhibiting type I collagen synthesis by activated HSCs, thereby providing a protective rather than pathologic role.

Xenobiotic exposure and autoimmune hepatitis

Although genetics contributes to the development of autoimmune diseases, it is clear that "environmental" factors are also required. These factors are thought to encompass exposure to certain drugs and environmental pollutants. This paper examines the mechanisms that normally maintain immune unresponsiveness in the liver and discusses how exposure to certain xenobiotics such as trichloroethylene may disrupt those mechanisms and promote autoimmune hepatitis.

Expression of fibrosis-related genes in canine chronic hepatitis

Molecular regulation of fibrosis in chronic canine hepatitis is poorly understood. The authors employed quantitative polymerase chain reaction (PCR) to determine the expression levels of genes reported to be related to fibrosis in other species (human, mouse, and rat) and to elucidate the relationship of these genes with the degree of fibrosis and the presence or absence of ascites and/or jaundice in dogs with hepatitis. Nine fibrosis-related genes were assayed: PDGFB, PDGFD, MMP2, TIMP1, THBS1, COL1A1, COL3A1, TGFB1, and TGFB2. Liver samples of 15 dogs with chronic hepatitis and 4 healthy control dogs were obtained via laparoscopic biopsy and subjected to histologic and quantitative PCR analyses. The expression of all 9 genes showed significant positive correlation (P<.01, r>.70) with the degree of fibrosis. Furthermore, the expression levels of all genes except TGFB1 were significantly higher (P<.05) in dogs with hepatic failure-related symptoms (ascites/jaundice). Results suggest that these 9 genes are integral to the development of fibrosis in canine chronic hepatitis.

Hepatoprotective role of bis-demethoxy curcumin analog on the expression of matrix metalloproteinase induced by alcohol and polyunsaturated fatty acid in rats

Liver fibrosis is one of the major health problems worldwide. Chronic alcohol abuse is one of the main causes of fibrosis. Ingestion of polyunsaturated fatty acids (PUFA) along with alcohol further aggravates the toxicity of alcohol. Fibrosis results due to increased deposition of extra cellular matrix (ECM). The degree of abnormal ECM degradation depends on the ratio of active matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). The present work studied the influence of bis-desmethoxy curcumin analog (BDMC-A) on the expression of MMPs and TIMPs during alcohol and DeltaPUFA induced liver toxicity. Male albino Wistar rats were used for the study. The MMP expression was found to be increased in alcohol as well as DeltaPUFA treated rats and decreased in alcohol + DeltaPUFA treated rats. The levels of TIMPs and the collagen were increased in alcohol, DeltaPUFA, and alcohol + DeltaPUFA groups. Administration of BDMC-A significantly decreased the levels of collagen and TIMPs; and positively modulated the expression of MMPs. From this study, it is concluded that BDMC-A influences MMPs, TIMPs expression, and acts as an efficient anti-fibrotic agent.

Serum MMP-7 is increased in diabetic renal disease and diabetic diastolic dysfunction

Circulating matrix metalloproteinase (MMP) levels may correlate with diabetic complications. Whether they are changed in early diabetic cardiomyopathy is not known and was examined in this study. TIMP-1 and collagen degradation products were also measured. Results from subjects with and without diastolic dysfunction were compared with those obtained for patients with varying stages of diabetic renal disease. Patients with type 2 diabetes with or without diastolic dysfunction with varying degrees of renal disease were recruited for this study. Age-matched non-diabetic subjects served as controls. MMPs (-1, -3 and -7) and TIMP-1 were measured by ELISA, MMP-2 and -9 by zymography and collagen degradation products by radioimmunoassay. Differences in the pattern of MMPs/TIMPs and collagen degradation products were observed. The most consistent change was in totalMMP-7, which was increased in those with diastolic dysfunction and those with macroalbuminuria. MMP-7 correlated with cardiac function (p<0.05 vs control, in those with diastolic dysfunction), and renal filtration function (p<0.05 vs control). In summary, we have identified novel relationships between serum MMP-7 and diabetic complications specifically in renal disease and in diastolic dysfunction. How increased circulating MMP-7 is associated with these diabetic microvascular complications and the significance of these findings will require prospective studies.