Late-stage Fibrosis Research Articles

MiRNA-221 and miRNA-222 are promising biomarkers for progression of liver fibrosis in HCV Egyptian patients

Current methodologies used to determine the progression of hepatic fibrosis rely heavily on liver biopsy, a dangerous and invasive procedure, with semi-subjective analysis of the results of the biopsy. Thus, a new approach is immensely needed for monitoring the progression of liver fibrosis in Hepatitis C virus (HCV) patients. The purpose of this study was to find highly specific and sensitive miRNA biomarkers that can be used to detect different stages of liver fibrosis. The study consisted of 42 cases of chronic hepatitis C (CHC) with early-stage fibrosis, 45 cases of CHC with late-stage fibrosis, and 40 healthy subjects with no CHC or fibrosis as controls. Expression patterns of 5 miRNAs (miR-16, miR-146a, miR-214-5p, miR-221, and miR-222) were analyzed in each group using TaqMan real-time PCR. Serum levels of miRNA-16, miRNA-146a, miRNA-221, and miRNA-222 were all significantly up-regulated in early and late stages of liver fibrosis. miRNA-222 had the highest sensitivity and specificity values in early and late fibrosis. miRNA-221 had the second highest sensitivity and specificity with the late-stage fibrosis group. Furthermore, miRNA-221 showed significant positive correlations with both miRNA-16 and miRNA-146a in the early- and late-stage fibrosis groups, with the early stage having a stronger correlation. The results indicated that miRNA-16, miRNA-146a, miRNA-221, and miRNA-222 can be used to detect the presence of liver fibrosis. The high sensitivity and specificity of miRNA-222 and miRNA-221 in late-stage fibrosis indicate promising prognostic biomarkers for HCV-induced liver fibrosis.

Effects of dynamic changes in histone acetylation and deacetylase activity on pulmonary fibrosis

Histone deacetylases (HDACs) play an important role in dysregulation of histone acetylation/deacetylation, which is the main driving force of the progression of pulmonary fibrosis. Here we investigated the changes in histone acetylation/deacetylation, and the contribution of specific class I and class II HDACs in the progression of pulmonary fibrosis. Male C57BL/6J mice received a single dose of tracheal administration of bleomycin to establish the pulmonary fibrosis model. The changes in acetylation rate of histone 3 (H3) and histone 4 (H4), and the activity of HDAC2 and HDAC4 in the lung tissue during the progression from alveolitis to pulmonary fibrosis were measured. The acetylation rate of H3/H4 significantly decreased during alveolitis and the early and middle stages of fibrosis, but restored in the late stage of fibrosis. Correlation analysis showed that H4 deacetylation affected both alveolitis and pulmonary fibrosis. H3 deacetylation only affected alveolitis. HDAC2 activity significantly increased in the middle and late stages of pulmonary fibrosis. There was no significant difference in HDAC4 activity between bleomycin and saline groups. However, HDAC4 activity changed significantly with the progression of the disease in bleomycin group. The changes in HDAC2 and HDAC4 activity were different. HDAC2 had long-lasting effects, while HDAC4 had transient effects. Correlation analysis showed that HDAC2 and HDAC4 activity was positively correlated with alveolitis score and fibrosis score. The changes in histone acetylation may directly regulate the gene expression of inflammatory cytokines/fibronectin and thus affect the progression of pulmonary fibrosis. The injury-induced histone deacetylation switched into acetylation at the late stage of pulmonary fibrosis, which may be involved in the repair process. HDAC2 is mainly involved in the chronic progression of pulmonary fibrosis, and HDAC4 is mainly involved in early stress response to pulmonary fibrosis.

The loss of Krüppel-like factor 15 in Foxd1+ stromal cells exacerbates kidney fibrosis

Large epidemiological studies clearly demonstrate that multiple episodes of acute kidney injury contribute to the development and progression of kidney fibrosis. Although our understanding of kidney fibrosis has improved in the past two decades, we have limited therapeutic strategies to halt its progression. Myofibroblast differentiation and proliferation remain critical to the progression of kidney fibrosis. Although canonical Wnt signaling can trigger the activation of myofibroblasts in the kidney, mediators of Wnt inhibition in the resident progenitor cells are unclear. Recent studies demonstrate that the loss of a Krüppel-like factor 15 (KLF15), a kidney-enriched zinc-finger transcription factor, exacerbates kidney fibrosis in murine models. Here, we tested whether Klf15 mRNA and protein expression are reduced in late stages of fibrosis in mice that underwent unilateral ureteric obstruction, a model of progressive renal fibrosis. Knockdown of Klf15 in Foxd1-expressing cells (Foxd1-Cre Klf15fl/fl) increased extracellular matrix deposition and myofibroblast proliferation as compared to wildtype (Foxd1-Cre Klf15+/+) mice after three and seven days of ureteral obstruction. This was validated in mice receiving angiotensin II treatment for sixweeks. In both these murine models, the increase in renal fibrosis was found in Foxd1-Cre Klf15fl/fl mice and accompanied by the activation of Wnt/β-catenin signaling. Furthermore, knockdown of Klf15 in cultured mouse embryonic fibroblasts activated canonical Wnt/β-catenin signaling, increased profibrotic transcripts, and increased proliferation after treatment with a Wnt1 ligand. Conversely, the overexpression of KLF15 inhibited phospho-β-catenin (Ser552) expression in Wnt1-treated cells. Thus, KLF15 has a critical role in attenuating kidney fibrosis by inhibiting the canonical Wnt/β-catenin pathway.

Prevalence and economic burden of extrahepatic manifestations of hepatitis C virus are underestimated but can be improved with therapy.

Despite guideline recommendations, access to hepatitis C virus (HCV) treatment is frequently restricted, with some payers approving therapy for only those with advanced disease or cirrhosis. However, delaying potentially curative treatment until the development of advanced liver disease may have costly consequences in terms of both hepatic complications and extrahepatic manifestations (EHMs) of HCV. Using a large claims database from the United States, we measured the risks and medical costs of 20 EHMs and investigated the role of treatment in different stages of liver fibrosis for mitigating the clinical and economic burden of these EHMs. After adjusting for potential confounders, including comorbid liver disease, patients with HCV had a significantly higher risk for any EHM (adjusted odds ratio, 2.23; P < 0.05) and higher EHM‐related annual medical costs (adjusted medical cost difference, $6,458; P < 0.05) compared to matched patients without HCV. HCV treatment can offset the higher medical costs in patients with HCV by saving ∼$25,000 in all‐cause medical costs per patient per year, with a large proportion attributable to savings in EHM‐related medical costs (adjusted cost difference $12,773, P < 0.05). Finally, additional EHM‐related medical costs could be saved by initiating HCV therapy in early stage fibrosis as opposed to late‐stage fibrosis (adjusted medical cost difference, $10,409; P < 0.05). Conclusion: The clinical and economic burden of EHMs is substantial and can be reduced through viral eradication, especially if treatment is initiated early and not delayed until fibrosis advances. Considering that the wholesale acquisition cost of a 12‐week course of therapy ranges from $55,000 to $147,000, the results of the current study suggest the cost of these treatments could be offset within 3 to 6 years by savings in all‐cause medical costs. (Hepatology Communications 2017;1:439–452)

Validation of a serum microRNA panel as biomarkers for early diagnosis of hepatocellular carcinoma post-hepatitis C infection in Egyptian patients.

AIMTo investigate the prospective importance of serum micro (mi)RNAs (miR-125b, miR-138b, miR-1269, miR-214-5p, miR-494, miR375 and miR-145) as early biomarkers for the diagnosis of hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC).METHODSTwo-hundred and fifty HCV4a patients, 224 HCV4a-HCC patients, and 84 healthy controls were enrolled in the study. Expression levels of miR214-5p, miR-125b, miR-1269 and miR-375 were quantified using quantitative real-time PCR.RESULTSExpression of the selected miRNAs in serum was significantly lower in HCC patients than in the healthy controls, except for miR-1269 and miR-494. There was a significant difference between HCC and HCV patients, in particular for HCC and late stage fibrosis, rather than HCV patients and early fibrosis. It is obvious that miR-1269 was significantly upregulated in HCC cases compared to hepatic fibrosis cases. Each miRNA can show HCC progression. Multivariate logistic regression analysis indicated that the tested panel of miRNAs (miR214-5p, miR-125b, miR-1269 and miR-375) represent accurate and specific indictors of HCC development.CONCLUSIONThis study presents a panel of miRNAs with strong power as putative diagnostic and prognostic biomarkers for HCV-induced HCC. Moreover, miR-214-5p and miR-1269 could be considered as early biomarkers for tracking the progress of liver fibrosis to HCC.

Circulating miRNAs as Predictor Markers for Activation of Hepatic Stellate Cells and Progression of HCV-Induced Liver Fibrosis.

IntroductionLiver fibrosis is the excessive accumulation of extracellular matrix that occurs by activation of hepatic stellate cells (HSCs), which has been identified as the major driver of liver fibrosis. Several studies confirmed that miRNAs have regulatory effects on the activation of HSCs by affecting the signaling pathways. The aim of this study was to develop non-invasive diagnostic markers by measuring different circulating miRNAs in serum as predictor markers for early diagnosis of liver fibrosis and its progression.MethodsIn this case-control study, we enrolled 66 subjects with chronic hepatitis C (CHC) with early stage of fibrosis and 65 subjects with CHC with late-stage fibrosis. Also, 40 subjects were included as normal controls. The six main miRNAs, i.e., miR-138, miR-140, miR-143, miR-325, miR-328, and miR-349, were measured using the reverse transcription-polymerase chain reaction.ResultsIn the cases of CHC both with early and late stage of fibrosis, the circulating levels of the six main miRNAs were significantly higher than the levels in the control group. ROC analysis indicated that the sensitivity and specificity of miR-138 were 89.3% and 71.43%, respectively, in the early stage of fibrosis. In the late stage, the sensitivity and specificity of miR-138 were 89.3 and 93.02%, respectively, whereas, for miR-143, they were 75.0 and 88.4%, respectively.ConclusionsCirculating miR-138 could serve as a non-invasive biomarker for the detection of early fibrosis. Also, miR-138 and miR-143 could be specific biomarkers for indicating the late stage of liver fibrosis.

Identification of cromolyn sodium as an anti-fibrotic agent targeting both hepatocytes and hepatic stellate cells

Liver fibrosis and cirrhosis, the late stage of fibrosis, are threatening diseases that lead to liver failure and patient death. Although aberrantly activated hepatic stellate cells (HSCs) are the main cause of disease initiation, the symptoms are primarily related to damaged hepatocytes. Thus, damaged hepatocytes, as well as HSCs, need to be simultaneously considered as therapeutic targets to develop more efficient treatments. Here, we suggest cromolyn sodium as an anti-fibrotic agent to commonly modulate hepatocytes and hepatic stellate cells. The differentially expressed genes from 6 normal and 40 cirrhotic liver tissues which were collected from GEO data were assessed by pharmacokinetic analysis using a connectivity map to identify agents that commonly revert abnormal hepatocytes and HSCs to normal conditions. Based on a series of analyses, a few candidates were selected. Candidates were tested in vitro to determine their anti-fibrotic efficacy on HSCs and hepatocytes. Cromolyn, which was originally developed as a mast cell stabilizer, showed the potential to ameliorate activated HSCs in vitro. The activation and collagen accumulation for HSC cell lines LX2 and HSC-T6 were reduced by 50% after cromolyn treatment at a low concentration without apoptosis. Furthermore, cromolyn treatment compromised the TGF-β-induced epithelial mesenchyme transition and replicative senescence rate of hepatocytes, which are generally associated with fibrogenesis. Taken together, cromolyn may be the basis for an effective cure for fibrosis and cirrhosis because it targets both HSCs and hepatocytes.

Automated biphasic morphological assessment of hepatitis B-related liver fibrosis using second harmonic generation microscopy.

Liver fibrosis assessment by biopsy and conventional staining scores is based on histopathological criteria. Variations in sample preparation and the use of semi-quantitative histopathological methods commonly result in discrepancies between medical centers. Thus, minor changes in liver fibrosis might be overlooked in multi-center clinical trials, leading to statistically non-significant data. Here, we developed a computer-assisted, fully automated, staining-free method for hepatitis B-related liver fibrosis assessment. In total, 175 liver biopsies were divided into training (n = 105) and verification (n = 70) cohorts. Collagen was observed using second harmonic generation (SHG) microscopy without prior staining, and hepatocyte morphology was recorded using two-photon excitation fluorescence (TPEF) microscopy. The training cohort was utilized to establish a quantification algorithm. Eleven of 19 computer-recognizable SHG/TPEF microscopic morphological features were significantly correlated with the ISHAK fibrosis stages (P < 0.001). A biphasic scoring method was applied, combining support vector machine and multivariate generalized linear models to assess the early and late stages of fibrosis, respectively, based on these parameters. The verification cohort was used to verify the scoring method, and the area under the receiver operating characteristic curve was >0.82 for liver cirrhosis detection. Since no subjective gradings are needed, interobserver discrepancies could be avoided using this fully automated method.

3D molecular MR imaging of liver fibrosis and response to rapamycin therapy in a bile duct ligation rat model

Liver biopsy, the gold standard for assessing liver fibrosis, suffers from limitations due to sampling error and invasiveness. There is therefore a critical need for methods to non-invasively quantify fibrosis throughout the entire liver. The goal of this study was to use molecular Magnetic Resonance Imaging (MRI) of Type I collagen to non-invasively image liver fibrosis and assess response to rapamycin therapy. Liver fibrosis was induced in rats by bile duct ligation (BDL). MRI was performed 4, 10, or 18 days following BDL. Some BDL rats were treated daily with rapamycin starting on day 4 and imaged on day 18. A three-dimensional (3D) inversion recovery MRI sequence was used to quantify the change in liver longitudinal relaxation rate (ΔR1) induced by the collagen-targeted probe EP-3533. Liver tissue was subjected to pathologic scoring of fibrosis and analyzed for Sirius Red staining and hydroxyproline content. ΔR1 increased significantly with time following BDL compared to controls in agreement with ex vivo measures of increasing fibrosis. Receiver operating characteristic curve analysis demonstrated the ability of ΔR1 to detect liver fibrosis and distinguish intermediate and late stages of fibrosis. EP-3533 MRI correctly characterized the response to rapamycin in 11 out of 12 treated rats compared to the standard of collagen proportional area (CPA). 3D MRI enabled characterization of disease heterogeneity throughout the whole liver. EP-3533 allowed for staging of liver fibrosis, assessment of response to rapamycin therapy, and demonstrated the ability to detect heterogeneity in liver fibrosis.

First in man: Amniotic stem cell injection promotes scar remodeling and healing processes in late-stage fibrosis

First in man: Amniotic stem cell injection promotes scar remodeling and healing processes in late-stage fibrosis

Thymosin β4 and its degradation product, Ac-SDKP, are novel reparative factors in renal fibrosis

Previously we found thymosin β4 (Tβ4) is up-regulated in glomerulosclerosis and required for angiotensin II-induced expression of plasminogen activator inhibitor-1 (PAI-1) in glomerular endothelial cells. Tβ4 has beneficial effects in dermal and corneal wound healing and heart disease yet its effects in kidney disease are unknown. Here we studied renal fibrosis in wild type and PAI-1 knockout mice following unilateral ureteral obstruction to explore the impact of Tβ4 and its prolyl oligopeptidase tetrapeptide degradation product, Ac-SDKP, in renal fibrosis. Additionally, we explored interactions of Tβ4 with PAI-1. Treatment with Ac-SDKP significantly decreased fibrosis in both wild type and PAI-1 knockout mice, as observed by decreased collagen and fibronectin deposition, fewer myofibroblasts and macrophages, and suppressed pro-fibrotic factors. In contrast, Tβ4 plus a prolyl oligopeptidase inhibitor significantly increased fibrosis in wild type mice. Tβ4 alone also promoted repair and reduced late fibrosis in wild type mice. Importantly, both pro-fibrotic effects of Tβ4 plus the prolyl oligopeptidase inhibitor, and late reparative effects of Tβ4 alone, were absent in PAI-1 knockout mice. Thus, Tβ4 combined with prolyl oligopeptidase inhibition, is consistently pro-fibrotic, but by itself, has anti-fibrotic effects in late stage fibrosis, while Ac-SDKP has consistent anti-fibrotic effects in both early and late stages of kidney injury. These effects of Tβ4 are dependent on PAI-1.

Telmisartan Plus Propranolol Improves Liver Fibrosis and Bile Duct Proliferation in the PSC-Like Abcb4−/− Mouse Model

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease leading to cirrhosis and cholangiocellular carcinoma. Inhibitors of the renin-angiotensin system or the sympathetic nervous system delay liver fibrogenesis in animal models. We investigated the antifibrotic potential of telmisartan, an angiotensin II type 1 receptor antagonist, and the β-adrenoceptor blocker propranolol in the PSC-like Abcb4 knockout mouse model. Sixty-five Abcb4 (-/-) mice were treated with telmisartan for 3 or 5 months (T) and with telmisartan plus propranolol for 3, 5, or 8 months (TP), or for 2 or 5 months starting with a delay of 3 months (TP delayed). Liver hydroxyproline content, inflammation, fibrosis, and bile duct proliferation were assessed; fibrosis-related molecules were analyzed by real-time polymerase chain reaction and Western blotting. Compared to controls, telmisartan monotherapy had no significant influence on hydroxyproline; however, telmisartan plus propranolol reduced hydroxyproline (TP 3 months, p = 0.008), fibrosis score (TP 3 months and TP 8 months, p = 0.043 and p = 0.008, respectively; TP delayed 8 months, p < 0.0005), bile duct proliferation (TP 8 months and TP delayed 8 months, p = 0.006 and p < 0.0005, respectively), and procollagen α1(I), endothelin-1, TIMP-1 and MMP3 mRNA as well as α-SMA, CK-19, and TIMP-1 protein. Telmisartan plus propranolol reduces liver fibrosis and bile duct proliferation in the PSC-like Abcb4 (-/-) mouse model, even when started at late stages of fibrosis, and may thus represent a novel therapeutic option for cholestatic liver diseases such as PSC.

Dialysis Reduces Portal Pressure in Patients With Chronic Hepatitis C

The purpose of this study was to characterize changes in hepatic venous pressures in patients with chronic hepatitis C. The histology and laboratory data from patients with chronic hepatitis C who underwent a transjugular liver biopsy (TJLB) and hepatic venous pressure gradient measurement were analyzed. Portal hypertension was defined as hepatic venous pressure gradient > or =6 mm Hg. A single pathologist masked to hepatic venous pressure gradient scored liver sections for inflammation and fibrosis. The patients with high-grade inflammation (relative risk [RR] 2.82, P = 0.027, multivariate analysis) and late-stage fibrosis (RR 2.81, P = 0.022) were more likely to have a hepatic venous pressure gradient > or =6 mm Hg, while the patients on dialysis (RR 0.32, P = 0.01) were less likely to have a hepatic venous pressure gradient > or =6 mm Hg. The patients on dialysis (n = 58) had an elevated serum blood urea nitrogen and creatinine when compared with those who were not (n = 75) (47.6 +/- 3.3 and 7.98 +/- 0.4 vs. 25.9 +/- 2.0 and 1.66 +/- 0.22 mg/dL, respectively; P < 0.001). While the hepatic venous pressure gradient increased with the rising levels of liver fibrosis in the latter group (P < 0.01), it did not change in the patients on dialysis (P = 0.41). The median hepatic venous pressure gradient was especially low in late-stage fibrosis patients on dialysis when compared with the latter group (5 vs. 10 mm Hg, P = 0.017). In patients on dialysis, serum transaminases were low across all levels of fibrosis. Twenty-three of the 92 patients with early fibrosis had a hepatic venous pressure gradient > or =6 mm Hg. In patients with chronic hepatitis C, concomitant TJLB and hepatic venous pressure gradient measurement identify those who have early fibrosis and portal hypertension. Long-term hemodialysis may reduce portal pressure in these patients.

The Level of Connective Tissue Growth Factor in Sera of Patients with Hepatitis B Virus Strongly Correlates with Stage of Hepatic Fibrosis

Connective tissue growth factor (CTGF) plays a crucial role in the formation and development of hepatic fibrosis. The aim of this study was to establish a method for CTGF determination in order to investigate the level of CTGF in the sera of patients with hepatitis B virus, and to assess the correlation between CTGF concentration and stage of hepatic fibrosis. A CTGF C-terminal region gene was obtained by RT-PCR of human mesangial kidney cells and inserted into pET-32a((+)) vector. Recombinant protein was obtained by expression and purification of the fused protein. Polyclonal and monoclonal antibodies were prepared to establish a sandwich ELISA method. CTGF levels in 18 healthy serum samples and 83 serum samples from patients with hepatitis B virus were assessed. A simple, sensitive, and noninvasive method of determining CTGF levels was successfully established. CTGF levels in the sera of patients with hepatitis B were significantly increased compared controls (p < 0.001). There was a strong correlation between CTGF concentration and fibrotic stage (r = 0.8906, p < 0.005). No significant association was found between CTGF level and the grade of hepatic inflammation (p > 0.05). The area under the receiver operating characteristic (ROC) curves of CTGF was 0.681 for identification of significant fibrosis, and 0.759 for the diagnosis of middle- and late-stage fibrosis. Accuracy of CTGF assessment was independent of age, renal function, liver function, platelet count, or other biochemical markers of liver fibrosis (all p > 0.05). No significant correlation was found between CTGF and several humoral factors associated with liver fibrosis (all p > 0.05). The levels of CTGF in the sera of patients with hepatitis B were strongly associated with the stages of hepatic fibrosis, and CTGF may become a useful diagnostic aid in assessing hepatic fibrosis.

Diverse roles of invariant natural killer T cells in liver injury and fibrosis induced by carbon tetrachloride #

Liver fibrosis is a common scarring response to all forms of chronic liver injury and is always associated with inflammation that contributes to fibrogenesis. Although a variety of cell populations infiltrate the liver during inflammation, it is generically clear that CD8 T lymphocytes promote while natural killer (NK) cells inhibit liver fibrosis. However, the role of invariant natural killer T (iNKT) cells, which are abundant in the liver, in hepatic fibrogenesis, remains obscure. Here we show that iNKT-deficient mice are more susceptible to carbon tetrachloride (CCl(4))-induced acute liver injury and inflammation. The protective effect of naturally activated iNKT in this model is likely mediated via suppression of the proinflammatory effect of activated hepatic stellate cells. Interestingly, strong activation of iNKT through injection of iNKT activator alpha-galactosylceramide (alpha-GalCer) accelerates CCl(4)-induced acute liver injury and fibrosis. In contrast, chronic CCl(4) administration induces a similar degree of liver injury in iNKT-deficient and wild-type mice, and only a slightly higher grade of liver fibrosis in iNKT-deficient mice than wild-type mice 2 weeks but not 4 weeks after CCl(4) injection, although iNKT cells are able to kill activated stellate cells. An insignificant role of iNKT in chronic liver injury and fibrosis may be attributable to hepatic iNKT cell depletion. Finally, chronic alpha-GalCer treatment had little effect on liver injury and fibrosis, which is attributable to iNKT tolerance after alpha-GalCer injection. Natural activation of hepatic iNKT cells inhibits, whereas strong activation of iNKT cells by alpha-GalCer accelerates CCl(4)-induced acute liver injury, inflammation, and fibrosis. During chronic liver injury, hepatic iNKT cells are depleted and play a role in inhibiting liver fibrosis in the early stage but not the late stage of fibrosis.

Dynamic changes of type I,III and IV collagen synthesis and distribution of collagen-producing cells in carbon tetrachloride-induced rat liver fibrosis.

AIM:To find out the relationship between the gene transcription of different types of procollagen and the deposition of the relevant collagens in the liver tissue and to confirm the types of collagen producing cells in liver fibrogenesis.METHODS:Dynamic changes of the expression of alpha1(I), alpha1(III) and alpha1(IV) procollagen mRNA and relevant collagens and the distribution of collagen producing cells during liver fibrogenesis of rat induced by CCl(4) (20 weeks) were investigated with Northern blot analysis, in situ hybridization and immunohistochemical techniques.RESULTS: The increased expression of alpha 1(III) procollagen mRNA by Northern blot analysis was the most predominant one among the three mRNAs during fibrogenesis. However, the enhanced expression of alpha1(IV) procollagen mRNA occurred very early while the expression of alpha1(I) mRNA was not enhanced much until the middle stage of the experiment. Desmin (Dm) positive hepatic stellate cells (HSCs) and few myofibroblasts (MFs) in and around the necrotic areas expressed alpha1(I), alpha1(III) and alpha1(IV) procollagen mRNA signals detected by in situ hybridization at the early stage of the experiment. All the three procollagen mRNA signals thereafter mainly localized in fibroblasts (Fbs) and MFs in fibrotic septa during the middle and late stages of fibrosis, which distributed parallel to the corresponding collagens detected by immunohistochemical study. In addition, the endothelial cells of sinusoids and the small blood vessels within the septa also showed alpha1(IV) procollagen mRNA and type IV collagen expression.CONCLUSION:It is considered that "HSC-MF-Fb effect cell system is the major cellular source of collagen production in liver fibrosis, in which HSCs are collagen producing precursor cells in the early liver fibrogenesis, thereafter the synthesis of type I, III and IV collagens (Col I, Col III and Col IV) mainly derives from MFs and Fbs, which play a very important role in the progress of liver fibrosis. The endothelial cells along sinusoids, as another source of Col IV production, might participate in the capillization of liver sinusoids.

Pathogenesis of systemic sclerosis: A vascular hypothesis

YSTEMIC SCLEROSIS, or scleroderma, is a generalized multisystem S disease in which the cutaneous features dominate the patient’s appearance, but visceral involvement determines the patient’s survival. Historically, scleroderma was thought to be an affliction of the skin, but cumulative evidence of visceral involvement led Goetzl to propose the term “progressive systemic sclerosis” (the lack of progression in many patients has led recent observers to use the term “systemic sclerosis” as essentially synonymous with scleroderma). In both the identification and early investigation of scleroderma, emphasis centered on the late-stage fibrosis; more recent interest has been in the widespread vascular involvement and its potential as a unifying pathogenetic concept. The study and review of the 261 cases of systemic sclerosis seen at ColumbiaPresbyterian Medical Center over the past 20 yr has led to a conceptual scheme, speculative in part, of etiology and pathophysiology which emphasizes the vascular tree as a target organ in systemic sclerosis. This hypothesis, linking inflammatory, proliferative, and indurative phases of the vascular lesion, is presented on a background of the general features of systemic sclerosis and is extended to highlight specific points in the management of organ involvement. Since several recent reviews provide excellent, detailed coverage of the disease, only those aspects which contribute to our understanding of this hypothesis will be included here.2*4*5J’ CLINICAL FEATURES Systemic sclerosis primarily victimizes middle-aged women. Though the literature reports about a three-to-one ratio of females to males, our experience approaches a four-to-one ratio.4*8*8 While Medsger and Masi report the incidence to be equal in blacks and whites,6 80% of our series is white; however, the large number of referral patients probably accounts for this difference. A reported incidence rate of 2-12 cases per million people per year reveals the uncommon, but