The Impact of Radiofrequency Ablation on Survival Outcomes and Stent Patency in Patients with Unresectable Cholangiocarcinoma: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Endoluminal biliary radiofrequency ablation (RFA) has been proposed as a palliative treatment for patients with malignant biliary obstruction (MBO) in order to improve stent patency and survival. However, the existing data on patients with inoperable extrahepatic cholangiocarcinoma (eCCA) are conflicting. We performed a meta-analysis of randomized trials comparing RFA plus stenting versus stenting alone in patients with inoperable eCCA. We searched for trials published in the PubMed/MEDLINE, Scopus, and Cochrane databases up to November 2023. Data extraction was conducted from published studies, and a quality assessment was carried out in accordance with the guidelines recommended by the Cochrane Collaboration. Hazard ratios (HRs) with 95% CI were estimated from the trials. The primary endpoints of interest were overall survival and stent patency. Out of 275 results, 5 randomized trials and 370 patients were included. While overall survival was not different between the groups (HR 0.62; 95% CI 0.36-1.07; p = 0.09; I2 = 80%;), the subgroup analysis of studies employing plastic stents showed a trend toward better survival in the RFA-treated group (HR 0.42; 95% CI 0.22-0.80; p = 0.009; I2 = 72%). Stent patency was improved in patients receiving RFA (HR 0.64; 95% CI 0.45-0.90; p = 0.01; I2 = 23%). Adverse events were not different between the groups (OR 1.21; 95% CI 0.69-2.12; p = 0.50; I2 = 0%). Despite the promising results, high heterogeneity and potential biases in the included studies suggest the need for further high-quality randomized trials to explore the potential cumulative effects of RFA on CCA treatment outcomes.

Ustekinumab safety and effectiveness in patients with ulcerative colitis: results from a large real-life study

BACKGROUND

Ustekinumab (UST) is an interleukin-12/interleukin-23 receptor antagonist recently approved for treating ulcerative colitis (UC) but with limited real-world data. Therefore, we evaluated the effectiveness and safety of UST in patients with UC in a real-world setting.

RESEARCH DESIGN AND METHODS

This is a multicenter, retrospective, observational cohort study. The primary endpoints were the clinical remission rate (partial Mayo score, PMS, ≤1) and the safety of UST. Other endpoints were corticosteroid-free remission (CSFR) rate, clinical response rate (PMS reduction of at least 2 points), and fecal calprotectin (FC) reduction at week 24.

RESULTS

We included 256 consecutive patients with UC (M/F 139/117, median age 52). The clinical remission and clinical response rates at eight weeks were 18.7% (44/235) and 53.2% (125/235), respectively, and 27.6% (42/152) and 61.8% (94/152) at 24 weeks, respectively. At 24 weeks, CSFR was 20.3% (31/152), and FC significantly dropped at week 12 (p = 0.0004) and 24 (p = 0.038). At eight weeks, patients naïve or with one previous biologic treatment showed higher remission (p = 0.002) and clinical >response rates (p = 0.018) than patients previously treated with ≥ 2. Adverse events occurred in six patients (2.3%), whereas four patients (1.6%) underwent colectomy.

CONCLUSION

This real-world study shows that UST effectively and safely treats patients with UC.

Upper Gastrointestinal Endoscopy Quality in Italy: A Nationwide Study

BACKGROUND AND AIMS

International guidelines advise improving esophagogastroduodenoscopy (EGD) quality in Western countries, where gastric cancer is still diagnosed in advanced stages. This nationwide study investigated some indicators for the quality of EGD performed in endoscopic centers in Italy.

METHODS

Clinical, endoscopic, and procedural data of consecutive EGDs performed in one month in the participating centers were reviewed and collected in a specific database. Some quality indicators before and during endoscopic procedures were evaluated.

RESULTS

A total of 3,219 EGDs performed by 172 endoscopists in 28 centers were reviewed. Data found that some relevant information (family history for GI cancer, smoking habit, use of proton pump inhibitors) were not collected before endoscopy in 58.5-80.7% of patients. Pre-endoscopic preparation for gastric cleaning was routinely performed in only 2 (7.1%) centers. Regarding the procedure, sedation was not performed in 17.6% of patients, and virtual chromoendoscopy was frequently (>75%) used in only one (3.6%) center. An adequate sampling of the gastric mucosa (i.e., antral and gastric body specimens) was heterogeneously performed, and it was routinely performed only by 23% of endoscopists, and in 14.3% centers.

CONCLUSIONS

Our analysis showed that the quality of EGD performed in clinical practice in Italy deserves to be urgently improved in different aspects.

Use of tofacitinib as first or second-line therapy is associated with better outcomes in patients with ulcerative colitis: data from a real-world study

BACKGROUND

Data regarding the real-world (RW) use of tofacitinib (TOF) in patients with ulcerative colitis (UC) are limited. We aimed to investigate TOF's RW efficacy and safety in Italian UC patients.

RESEARCH DESIGN AND METHODS

A retrospective assessment of clinical and endoscopic activity was performed according to the Mayo score. The primary endpoints were to evaluate the effectiveness and safety of TOF.

RESULTS

We enrolled 166 patients with a median follow-up of 24 (IQR 8-36) weeks. Clinical remission was achieved in 61/166 (36.7%) and 75/166 (45.2%) patients at 8-week and 24-week follow-ups, respectively. The optimization was requested in 27 (16.3%) patients. Clinical remission was achieved more frequently when TOF was used as a first/second line rather than a third/fourth line treatment (p = 0.007). Mucosal healing was reported in 46% of patients at the median follow-up time. Colectomy occurred in 8 (4.8%) patients. Adverse events occurred in 12 (5.4%) patients and severe in 3 (1.8%). One case of simple Herpes Zoster and one of renal vein thrombosis were recorded.

CONCLUSIONS

Our RW data confirm that TOF is effective and safe in UC patients. It performs remarkably better when used as the first/second line of treatment.

Serological response after anti-SARS-CoV-2 BNT162b2 vaccine in IBD patients on biological therapy: a monocentric case-control study

BACKGROUND

Inflammatory bowel disease (IBD) patients on biological therapy are receiving vaccines against severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2). However, it is unclear if IBD therapy could influence the response to this vaccine. In a case-control study, we assessed the antibody profiling after anti-SARS-CoV-2 BNT162b2 vaccine in IBD patients on biological therapy.

METHODS

We analyzed seroprevalence and antibody titer, after 14 weeks from the first BNT162b2 vaccine dose, in IBD patients on biological therapy and health care workers (HCWs). In IBD patients, medical history and disease data were recorded.

RESULTS

Eighty-two subjects were enrolled in this study. Among them, 40 were IBD patients on biological therapy and 42 were HCWs. All subjects developed an IgG anti-Spike antibody titer above the cut-off. IBD patients on biological therapy developed a lower antibody titer than HCWs (P<0.00001). No differences were reported in patients who received at least one dose of the vaccine within a period of 7 days from the last biological drug administration, compared to all other IBD patients. A difference was found between patients who were on concomitant immunosuppressive therapy and patients on sole biological therapy (P=0.0287). Patients with presence of any sign of disease activity (clinical, endoscopic or laboratory) showed a higher development of antibody titer compared to those in complete disease remission (P=0.0468).

CONCLUSIONS

Our data indicate that in IBD patients, treatment with biological therapies do not affect the seroprevalence but leads to a lower antibody titer development after anti-SARS-CoV-2 BNT162b2 vaccine.

Gastrointestinal Complications after Allogeneic Hematopoietic Stem Cell Transplant: A Multidisciplinary Approach with Early Endoscopic Evaluation

Gastrointestinal complications (GICs) represent the major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Differential diagnosis of GICs is of paramount importance since early and reliable identification of graft-versus-host disease (GVHD) is essential for a correct management of the patients. The aim of the present retrospective study was to evaluate the occurrence of GICs after allo-HSCT and to assess the diagnostic performance of a quick endoscopic and histological assessment in the differential diagnosis between GVHD and other GI conditions. Between January 2015 and August 2019, 122 consecutive patients receiving an allo-HSCT were managed by an interdisciplinary team, supported by a dedicated endoscopic service. Clinical, therapeutic, endoscopic and histological data were analyzed for each patient. Collectively, 94 of the patients developed GICs (77%). A moderate–severe mucositis was the most frequent complication, occurring in 79 patients (84%). Acute GI-GVHD was diagnosed in 35 patients (37% of whom with GICs) and 19 of them with a moderate–severe grade. Infective acute colitis developed in eight patients, mainly due to Clostridium difficile (CD) and Cytomegalovirus infections (8.5%). Rectal biopsy showed the highest sensitivity and specificity (80% and 100%, respectively). However, when biopsy procedures were guided by symptoms and performed on apparently intact mucosa, upper histology also provided a high negative predictive value (80%). Our multidisciplinary approach with a quick endoscopic/histologic investigation in the patients receiving an allo-HSCT and who suffered GICs could improve diagnostic and therapeutic management in this challenging setting.

Clinical and patient reported outcomes of the multidisciplinary management in patients with inflammatory bowel disease-associated spondyloarthritis

OBJECTIVE

Arthritis is the most frequent extra-intestinal manifestation in patients with inflammatory bowel diseases (IBD). The coexistence of intestinal and articular inflammation advocates the need for a multidisciplinary management of patients with IBD-associated spondyloarthritis.

METHODS

Consecutive IBD patients were evaluated jointly by the gastroenterologist and the rheumatologist in a combined clinic. All the patients were assessed and screened for articular involvement, disease activity and health related quality of life. After the prescription of a shared treatment, patients with spondyloarthritis were followed up for 24 months.

RESULTS

Two hundred sixty-two IBD patients, including 80 who were classified as affected by spondyloarthritis according to the ASAS criteria, were included in the study. At baseline, patients with both IBD and spondyloarthritis showed worse quality of life in both the physical and mental domains. The multidisciplinary management provided a significant improvement of gastrointestinal and articular manifestations, as well as the health-related quality of life. Moreover, global and gastrointestinal-specific quality of life significantly correlated with articular disease activity.

CONCLUSION

The multidisciplinary management significantly improves both articular and gastrointestinal disease activities and the quality of life of patients with IBD-associated spondyloarthritis. An appropriate screening strategy and the integrated management of these patients should be encouraged and employed in clinical practice.

Biologic Drugs in Crohn's Disease and Ulcerative Colitis: Safety Profile

Ulcerative Colitis (UC) and Crohn's Disease (CD) are chronic, progressive and disabling disorders characterized by a heterogeneous clinical course. Some years ago the main goal of the therapy was to achieve and maintain clinical remission, whereas at present the main goal of therapy is represented by the deep remission, characterized by sustained clinical remission, complete mucosal healing and normalization of serological markers of inflammation. In the last years new therapeutic approaches have been introduced which have led to a reduction in the mortality rate and have modified the natural history of Inflammatory Bowel Diseases (IBD). In addition, several prognostic factors have been identified which have allowed to better stratify the disease and to choose the most appropriate therapy for the single patient. Moreover, early treatment with immunosuppressive drugs and/or biologics has changed, at least in the short term, the course of the disease by reducing hospitalization rate and the need for surgery. Therefore, the development of biologic therapies has represented an important step in the treatment of IBD, since these drugs induce remission and response rates that are not achieved by other therapies. Since their use can result in significant adverse events that increase morbidity, patients must be aware of the risks associated with treatment and must be strictly monitored. Although treatment with biologic drugs is not successful in all patients and many of them lose clinical response, new therapies are currently under evaluation.

Helicobacter pylori infection in psoriasis: results of a clinical study and review of the literature

BACKGROUND

Data from the literature concerning the role of Helicobacter pylori (H. pylori) infection in psoriasis are still conflicting. This study was carried out to evaluate prevalence of H. pylori in patients with mild to severe psoriasis, correlation between H. pylori infection and severity of psoriasis, and effect of H. pylori eradication on the clinical course of psoriasis.

METHODS

Two hundred and ten patients with psoriasis and 150 healthy controls were screened for H. pylori through [(13) C] urea breath test at baseline (T0). All patients with psoriasis received standardized phototherapy treatment, and those infected by H. pylori were also treated with a 1-week triple therapy, then they were all re-evaluated four weeks later at the end of therapy (T5).

RESULTS

The prevalence of H. pylori was not higher in psoriasis than in the control group (20.27 vs. 22%; P > 0.05). Patients infected by H. pylori showed more severe psoriasis than uninfected patients (psoriasis area and severity index score 17.9 ± 7.1 vs. 13.7 ± 6.9; P = 0.04), and patients who received successful eradication of H. pylori infection showed a greater improvement of psoriasis than the others (psoriasis area and severity index score at T5 in patients infected by H. pylori was 8.36 ± 3.76, in uninfected patients was 10.85 ± 3.49; P = 0.006).

CONCLUSIONS

Patients with mild to severe psoriasis do not show a greater prevalence of H. pylori infection; however, H. pylori seems able to affect the clinical severity of psoriasis.

Role of small intestinal bacterial overgrowth and Helicobacter pylori infection in chronic spontaneous urticaria: a prospective analysis

The aim of this study is to assess the associations between chronic spontaneous urticaria (CSU), Helicobacter pylori infection and small intestinal bacterial overgrowth. Forty- eight patients with CSU were studied by scoring the urticaria activity and assesing the quality of life. Patients with H. pylori infection (n=11) or small intestinal bacterial overgrowth (n=13) were specifically treated for one week and clinically evaluated both before and 4 weeks after the eradication therapy. Eradication of H. pylori infection led to a significant improvement in CSU (p<0.002). In contrast, eradication of small intestinal bacterial overgrowth was not associated with any clinical improvement in CSU, despite the fact that these patients had statistically significant more urticaria activity at baseline. Thus there is no evidence to support the eradication of small intestinal bacterial overgrowth in CSU, but eradication of H. pylori infection may result in an improvement of the disease.

Gastrointestinal motility disorder assessment in systemic sclerosis

OBJECTIVES

SSc is a clinically heterogeneous and generalized disease, characterized by thickness of the connective tissue of the skin and internal organs, such as the digestive tract, impairing gastrointestinal (GI) motility. Our aim is to evaluate retrospectively abnormalities of oesophageal motility, gastric emptying, oro-cecal transit time (OCTT) and small intestine bacterial overgrowth (SIBO) in a large cohort of SSc patients.

METHODS

Ninety-nine SSc patients were included in the study. Forty-two patients underwent oesophageal conventional manometry, 45 performed a [(13)C]octanoic acid breath test to measure gastric emptying time and all 99 patients performed a lactulose breath test in order to evaluate OCTT and SIBO. Data were compared with healthy controls.

RESULTS

In SSc patients, median lower oesophageal sphincter (LOS) pressure [14 mmHg (25th-75th; 8-19) vs 24 mmHg (19-28); P < 0.01] and median wave amplitude [30 mmHg (16-70) vs 72 mmHg (48-96); P < 0.01] were lower than in controls. Oesophageal involvement, defined as reduced LOS pressure and ineffective oesophageal motility pattern, was encountered in 70% of SSc patients. A delayed gastric emptying time was present in 38% of SSc patients: mean t½ was 141 ± 79 min vs 90 ± 40 min of controls (P < 0.01). Also, OCTT was significantly delayed in SSc: median OCTT was 160 min (25th-75th; 135-180) vs 105 min (25th-75th; 90-135) of controls (P < 0.01). SIBO was observed in 46% of SSc compared with 5% of controls (P < 0.01).

CONCLUSION

GI involvement is very frequent in SSc patients. Oesophagus and small bowel are more frequently impaired, whereas delayed gastric emptying is less common.

Prevalence of small intestinal bacterial overgrowth in Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is associated with gastrointestinal motility abnormalities that could favor the occurrence of small intestinal bacterial overgrowth. The aim of the study was to assess the prevalence of small intestinal bacterial overgrowth in PD patients.

METHODS

Consecutive PD patients were enrolled. The controls were subjects without PD. All patients and controls underwent the glucose breath test to assess small intestinal bacterial overgrowth.

RESULTS

Forty-eight PD patients and 36 controls were enrolled. The prevalence of small intestinal bacterial overgrowth was significantly higher in PD patients than in controls (54.17% vs 8.33%; P < .0001; OR, 2.24; 95% CI, 3.50-48.24). Multivariate analysis showed Hoehn and Yahr stage (OR, 3.07; 95% CI, 1.14-8.27) and Unified PD Rating score (OR, 1.12; 95% CI, 1.02-1.23) were significantly associated with small intestinal bacterial overgrowth in PD patients.

CONCLUSIONS

Small intestinal bacterial overgrowth is highly prevalent in PD. Gastrointestinal motility abnormalities might explain this association.

Hepatoprotective and antifibrotic effect of a new silybin-phosphatidylcholine-Vitamin E complex in rats

BACKGROUND

Silybin, the main active component of silymarin, has been reported to reduce hepatic fibrosis by 30% in bile duct ligated rats, whereas Vitamin E alone does not significantly modify liver damage and collagen deposition in chronic liver injury.

AIM

The aim of the present study was to evaluate the hepatoprotective and the antifibrotic properties of a new silybin-phosphatidylcholine-Vitamin E complex, characterised by elevated oral bioavailability and lipophilicity, on rat hepatic fibrosis induced by dimethylnitrosamine administration and by bile duct ligation.

METHODS/RESULTS

The complex was administered by gastric gavage at a dose of 250 and 75 mg/kg (as silybin and Vitamin E, respectively). Treatment with the complex was able to prevent the dimethylnitrosamine-induced loss in body and liver weight, as well as to reduce the degree of liver injury, as determined by alanine aminotransferase values and necroinflammatory score. This was associated with reduced hepatic stellate cells proliferation both after 1 and 5 weeks of treatment. Treatment with the complex reduced also hepatic stellate cells activation and collagen deposition. Treatment with dimethylnitrosamine induced an increase in alpha1(I) procollagen, TGF(beta1), tissue inhibitor of metalloproteinase 1 and metalloproteinase 2 mRNA expression, which were significantly reduced by administration of the complex. In the bile duct ligation model, the administration of the complex was able to reduce hepatic stellate cells proliferation and activation, as well as collagen deposition and alpha1(I) procollagen mRNA expression.

CONCLUSIONS

These results suggest that this new silybin-phosphatidylcholine-Vitamin E complex could be an interesting drug to be tested in patients with chronic liver disease.

Effect of cyanidin 3-O-beta-glucopyranoside on hepatic stellate cell proliferation and collagen synthesis induced by oxidative stress

BACKGROUND

Reactive oxygen species play a role in the pathogenesis of hepatic fibrosis, mainly through the activation of hepatic stellate cells. Cyanidin-3-O-beta-glucopyranoside is a natural antioxidant compound distributed in several fruits and vegetables.

AIM

To evaluate the effect of cyanidin-3-O-beta-glucopyranoside on hepatic stellate cells proliferation and collagen synthesis induced by a pro-oxidant agent.

METHODS/RESULTS

Oxidative stress was induced by incubation of hepatic stellate cells with a ferric nitrilotriacetate complex (100 micromol/L). Incubation with ferric nitrilotriacetate induced an increased intracellular hydroperoxide formation, which was completely inhibited by cyanidin-3-O-beta-glucopyranoside at a concentration of 50mumol/L. Similarly, cyanidin-3-O-beta-glucopyranoside was able to inhibit ferric nitrilotriacetate-induced hepatic stellate cells proliferation, evaluated by an ELISA method, with a maximal effect at 50mumol/L. Incubation of hepatic stellate cells with cyanidin-3-O-beta-glucopyranoside inhibited ferric nitrilotriacetate-induced extracellular signal-regulated kinase 1/2 activation, evaluated by western blot, whereas it did not affect p70S6 kinase and AKT expression. Finally, cyanidin-3-O-beta-glucopyranoside reduced ferric nitrilotriacetate-induced Na(+)/H(+) exchange activation, evaluated by a spectrofluorimetric method, and collagen type I synthesis, evaluated by northern blot.

CONCLUSION

Cyanidin-3-O-beta-glucopyranoside is able to modulate hepatic stellate cells proliferation and type I collagen synthesis induced by a pro-oxidant agent, thus suggesting a potential role for this antioxidant compound in the prevention of fibrosis in chronic liver diseases.

The anti-fibrotic effect of pirfenidone in rat liver fibrosis is mediated by downregulation of procollagen alpha1(I), TIMP-1 and MMP-2

BACKGROUND

Pirfenidone (5 methyl-1-phenyl-2(1H)-pyridone) is a novel anti-fibrotic agent, which has been shown to decrease collagen deposition in a variety of animal models in vivo, and recently in hepatic fibrosis also. At cellular level, we have recently demonstrated that pirfenidone is able to inhibit proliferation of hepatic stellate cells induced by platelet-derived growth factor, as well as collagen type I accumulation and alpha1(I) procollagen mRNA expression.

AIMS

To evaluate if pirfenidone maintains its anti-fibrotic properties also when administered after the induction of hepatic damage and to further investigate the molecular mechanisms leading to the anti-fibrotic effect of pirfenidone.

METHODS AND RESULTS

Rats treated with dimethylnitrosamine (10 mg/kg) for 5 weeks received a liquid diet containing 0.5% pirfenidone starting from the third week. Pirfenidone treatment reduced the degree of liver injury, as determined by alanine aminotransferase values and necro-inflammatory score, which was associated with reduced hepatic stellate cells proliferation and collagen deposition. Treatment with dimethylnitrosamine increased transcripts levels for transforming growth factorbeta1, procollagen alpha1(I), tissue inhibitors of metalloproteinase-1 and matrix metalloproteinase-2 by 7-, 7-, 4- and 15-fold, respectively. Pirfenidone administration downregulated elevated levels of those transcripts by 50-60%, and this was associated with a 70% reduction in collagen deposition.

CONCLUSIONS

(1) Pirfenidone is effective also if administered after the induction of the hepatic damage; (2) the anti-fibrotic effect of pirfenidone is mainly due to the reduced expression of profibrogenic procollagen alpha1(I) and TIMP-1, most likely through the downregulation of transforming growth factorbeta1 mRNA, and of matrix metalloproteinase-2, which is mainly implicated in the degradation of the normal extracellular matrix.

Diagnosis of liver fibrosis

Hepatic fibrosis and cirrhosis represent the main consequence of chronic liver diseases of different origin. Therefore, the clinical assessment of disease severity is a must in the management of patients with chronic liver damage. Although liver biopsy may be associated with sampling error, interobserver variability and potential complications, it still remains the gold standard for establishing the severity of hepatic necroinflammation and fibrosis. In the last years, several non-invasive tests for the assessment of disease activity and stage have been proposed. However, at present all these tests are not totally accurate and reliable and need further evaluation.

Selective Na+/H+ exchange inhibition by cariporide reduces liver fibrosis in the rat

The aim of this study was to evaluate the effect of cariporide, a selective Na(+)/H(+) exchange inhibitor, on isolated and cultured hepatic stellate cells (HSCs) and in 2 in vivo models of rat liver fibrosis. Platelet-derived growth factor (PDGF)-induced HSC proliferation, evaluated by measuring the percentage of bromodeoxyuridine-positive cells, was significantly inhibited by cariporide, with a maximal effect at 10 micromol/L. Incubation with cariporide did not inhibit PDGF-induced extracellular-regulated kinase 1/2 (ERK1/2), Akt (a downstream component of the phosphatidylinositol [PI]-3 kinase pathway), and protein kinase C (PKC) activation but reduced PDGF-induced activation of the Na(+)/H(+) exchanger, with a maximal effect at 10 micromol/L. Rats treated with dimethylnitrosamine (DMN; 10 mg/kg) for 1 and 5 weeks received a diet with or without 6 ppm cariporide. Treatment with cariporide reduced the degree of liver injury, as determined by alanine aminotransferase (ALT) values, also when administered after the induction of hepatic damage. This was associated with reduced HSC activation and proliferation and reduced collagen deposition, as determined by morphometric evaluation of alpha-smooth muscle actin (SMA)/proliferating cell nuclear antigen-positive cells and percentage of Sirius red-positive parenchyma, respectively. Moreover, cariporide was also able to reduce alpha(1)I procollagen messenger RNA (mRNA) expression. Similar effects were observed in bile duct-ligated (BDL) rats. In conclusion, selective inhibition of the Na(+)/H(+) exchanger by cariporide may represent an effective therapeutic strategy in the treatment of hepatic fibrosis.

Effect of pirfenidone on rat hepatic stellate cell proliferation and collagen production

BACKGROUND/AIMS

Pirfenidone has been recently shown to reduce dimethynitrosamine-induced liver fibrosis in the rat, but no information are available on the effect of this drug on cultured hepatic stellate cells (HSC).

METHODS

HSC proliferation was evaluated by measuring bromodeoxyuridine incorporation; PDGF-receptor autophosphorylation, extracellular signal-regulated kinase (ERK1/2) and pp70(S6K) activation were evaluated by western blot; protein kinase C activation was evaluated by western blot and by ELISA; type I collagen accumulation and alpha1(I) procollagen mRNA expression were evaluated by ELISA and northern blot, respectively.

RESULTS

Pirfenidone significantly inhibited PDGF-induced HSC proliferation, starting at a concentration of 1 microM, with a maximal effect at 1000 microM, without affecting HSC viability and without inducing apoptosis. The inhibition of PDGF-induced HSC proliferation was associated neither with variations in PDGF-receptor autophosphorylation, or with ERK1/2 and pp70(S6K) activation. On the other hand, pirfenidone was able to inhibit PDGF-induced activation of the Na(+)/H(+) exchanger, which is involved in PDGF-induced HSC proliferation in HSC, with a maximal effect at 1000 microM and inhibited PDGF-induced protein kinase C activation. Pirfenidone 100 and 1000 microM inhibited type I collagen accumulation in the culture medium induced by transforming growth factor(beta1) by 54% and 92%, respectively, as well as TGF(beta1)-induced alpha1(I) procollagen mRNA expression.

RESULTS

Pirfenidone could be a new candidate for antifibrotic therapy in chronic liver diseases.

Rearrangement of the cytoskeletal network induced by platelet-derived growth factor in rat hepatic stellate cells: role of different intracellular signalling pathways

BACKGROUND/AIMS

Cytoskeletal reorganization plays an important role in the regulation of different cell functions, such as proliferation and migration. Since platelet-derived growth factor (PDGF) stimulates both proliferation and chemotaxis of hepatic stellate cells (HSC), we investigated the effects of this cytokine on cytoskeletal components of cultured rat HSC.

METHODS/RESULTS

Exposure of HSC to PDGF induced the formation of stress fibres and of a ruffled configuration of the plasma membrane, evaluated by both fluorescence and electron microscopy. These modifications were also induced by exposure to the protein kinase C (PKC) activator phorbol-12-myristate-13-acetate (PMA) and abolished by pretreatment with the PKC inhibitor calphostin C, with the Rho inhibitor C3 exoenzyme and with the intracellular calcium chelator MAPTAM, but not with the PI-3 kinase inhibitor wortmannin or with the mitogen-activated protein kinase kinase inhibitor PD 98059. PDGF induced a translocation of Rho from the cytosol to the membrane which was inhibited by C3 exoenzyme and by calpostin C, and which was also induced by PMA. Moreover, PDGF induced a rearrangement of vinculin which was prevented by C3 exoenzyme and calphostin C.

CONCLUSIONS

PDGF-induced cytoskeletal reorganization in HSC is dependent on PKC and Rho, thus suggesting that these two pathways may play an important role in the response of liver to injury.

Primary biliary cirrhosis: modalities of injury and death in biliary epithelium

BACKGROUND/AIM

Despite the number of studies on primary biliary cirrhosis, contrasting data remain concerning modalities of cholangiocyte death. Liver biopsies obtained from 40 patients with anti mitochondrial antibody-positive primary biliary cirrhosis, at various stages of the disease, were examined, and special attention was paid to the expression of subcellular damage and evidence of apoptosis.

METHODS

Liver sections were stained with haematoxylin/eosin or Sirius red. Ductular mass was evaluated on sections after cytokeratin 7 staining. Apoptosis was evaluated on haematoxylin/eosin stained material or after processing for terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling assay. In 16 patients, part of the biopsy was processed for electron microscopy. Twenty histologically normal liver biopsies were used for control purposes.

RESULTS

According to Scheuer's classification, 29 patients were classified as stage I-II, and 11 as stage III-IV. A strong staining of bile ducts was evident after immunohistochemistry for cytokeratin 7, often associated with ductular metaplasia in lobular zone 1. Cytokeratin 7-positive cells occupied 3.0+/-1.3% of liver mass as compared to 0.25+/-0.03% in controls. Ductular metaplasia accounted for 1.4+/-0.07% of all cytokeratin 7-positive cells. Regardless of staging, apoptotic bodies were seen only exceptionally in epithelial wall of bile ducts, whereas cholangiocyte damage leading to extensive lytic necrosis appeared responsible for most of the bile duct mass loss, as also confirmed by ultrastructural studies. A few terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling-positive nuclei were occasionally associated with the inflammatory infiltrate and evidence of apoptosis in hepatocytes was frequent, especially in zone 1.

CONCLUSION

Regardless of staging, lytic necrosis and not apoptosis accounts for most of the bile duct loss in primary biliary cirrhosis. Furthermore, ductular metaplasia appears as a late event with highly variable pattern being observed between patients.

Intracellular signaling pathways involved in acetaldehyde-induced collagen and fibronectin gene expression in human hepatic stellate cells

Ethanol induces liver fibrosis by several means that include, among others, the direct fibrogenic action of acetaldehyde on hepatic stellate cells (HSC). However the mechanisms responsible for this effect are not well understood. In this communication we investigated signal transduction pathways triggered by acetaldehyde leading to upregulation of alpha2(I) collagen and fibronectin gene expression in human HSC. Run-on assays showed that acetaldehyde-enhanced transcription of these 2 genes as early as 2 hours, via de novo protein synthesis-independent and -dependent mechanisms. It also stimulated a time-dependent induction in phosphorylation of pp70(S6K) and extracellular-regulated kinase (1/2) (ERK1/2). These effects were completely prevented by calphostin C, a protein kinase C inhibitor. As expected, acetaldehyde-elicited ERK1/2 phosphorylation was inhibited by PD98059, a MEK inhibitor, but not by wortmannin, a PI3K inhibitor. On the other hand, both of these inhibitors partially inhibited phosphorylation of pp70(S6K) induced by acetaldehyde suggesting that its activation is ERK1/2- and PI3K-dependent. Acetaldehyde-elicited fibronectin and alpha2(I) collagen upregulation was inhibited by calphostin C. However, while PD98059, wortmannin and rapamycin (a pp70(S6K) inhibitor) completely abrogated alpha2(I) collagen upregulation, they had no effect on fibronectin expression. Overall, these data suggest that protein kinase C is an upstream component from which acetaldehyde signals are transduced to other pathways such as PI3K and ERK1/2. In addition, differential activation of these pathways is needed for the increase in fibronectin and alpha2(I) collagen gene expression induced by acetaldehyde in human HSC.

Intracellular pH regulation and Na+/H+ exchange activity in human hepatic stellate cells: effect of platelet-derived growth factor, insulin-like growth factor 1 and insulin

BACKGROUND/AIMS

The Na+/H+ exchanger is involved in rat hepatic stellate cell (HSC) proliferation induced by platelet-derived growth factor (PDGF). We therefore evaluated in human HSC: (1) the mechanisms of intracellular pH regulation; (2) the relationship between Na+/H+ exchange activation and cell proliferation induced by PDGF, insulin-like growth factor 1 (IGF-1) and insulin.

METHODS/RESULTS

pH(i) regulation was mainly dependent on the activity of the Na+/H+ exchanger, which was evaluated by measuring pH(i) recovery from an acute acid load. PDGF (25 ng/ml) gradually increased the activity of the Na+/H+ exchanger which peaked at 18 h and remained stable until the 24th h. IGF-1 (10 nmol/l), but not insulin (100 nmol/l), slightly but significantly increased the activity of the Na+/H+ exchanger. Amiloride (100 micromol/l) and 20 micromol/l 5-N-ethyl-N-isopropyl-amiloride completely inhibited HSC proliferation (evaluated by measurement of bromodeoxyuridine incorporation) induced by PDGF and IGF-1, but did not affect proliferation of HSC induced by insulin. Finally, IGF-1 did not modify the activity of the Na+/Ca2+ exchanger.

CONCLUSIONS

The Na+/H+ exchanger is involved in HSC proliferation induced by PDGF and IGF-1, whereas the proliferative effect of insulin is mediated by intracellular pathways which are Na+/H+ exchange-independent.

Inhibition of the NA(+)/H(+) exchanger reduces rat hepatic stellate cell activity and liver fibrosis: an in vitro and in vivo study

BACKGROUND & AIMS

The Na(+)/H(+) exchanger is the main intracellular pH (pH(i)) regulator in hepatic stellate cells (HSCs) and plays a key role in regulating proliferation and gene expression. We evaluated the effect of specific inhibition of this exchanger on HSC proliferation and collagen synthesis in vivo and in vitro.

METHODS

Rat HSCs were incubated in the presence of platelet-derived growth factor (PDGF), transforming growth factor (TGF)-beta1, iron ascorbate (FeAsc), and ferric nitrilotriacetate solution (FeNTA) with or without the Na(+)/H(+) exchanger inhibitor 5-N-ethyl-N-isopropyl-amiloride (EIPA). pH(i) and Na(+)/H(+) exchanger activity, cell proliferation, and type I collagen accumulation were measured by using the fluorescent dye 2',7'-bis-(carboxyethyl)-5(6)-carboxyfluorescein, by immunohistochemistry for bromodeoxyuridine, and by enzyme-linked immunosorbent assay, respectively. In vivo liver fibrosis was induced by dimethylnitrosamine administration and bile duct ligation (BDL) in rats treated or not treated with amiloride.

RESULTS

PDGF, FeAsc, and FeNTA increased Na(+)/H(+) exchange activity and induced HSC proliferation. TGF-beta1 had no effect on the Na(+)/H(+) exchanger and was able, as for FeAsc and FeNTA, to induce type I collagen accumulation. EIPA inhibited all the effects determined by PDGF, FeAsc, and FeNTA and had no effect on TGF-beta1-induced collagen accumulation. In vivo, amiloride reduced HSC proliferation, activation, collagen deposition, and collagen synthesis.

CONCLUSIONS

The Na(+)/H(+) exchanger can play a key role in the development of liver fibrosis and in HSC activation in vivo.

Intracellular pathways mediating Na+/H+ exchange activation by platelet-derived growth factor in rat hepatic stellate cells

BACKGROUND & AIMS

The Na+/H+ exchanger is the main intracellular pH regulator in hepatic stellate cells (HSCs), and its activity is increased by platelet-derived growth factor (PDGF). Amiloride, an Na+/H+ exchange inhibitor, reduces PDGF-induced HSC proliferation, suggesting that the Na+/H+ exchanger plays a role in regulating HSC proliferative response. The aim of this study was to characterize the intracellular pathways mediating activation of the Na+/H+ exchanger by PDGF in HSCs.

METHODS

The activity of the Na+/H+ exchanger and HSC proliferation rate were evaluated under control condition and after incubation with PDGF in the absence or presence of specific inhibitors of the main intracellular pathways of signal transduction. Na+/H+ exchange protein expression was evaluated by means of Western blot.

RESULTS

PDGF induced a significant increase in the activity of the Na+/H+ exchanger without modifying protein expression. Inhibition of the calcium/calmodulin- and protein kinase C-dependent pathways resulted in a significant inhibition of both Na+/H+ exchange activity and of PDGF-induced HSC proliferation. The involvement of the two pathways was confirmed by showing that incubation of HSCs with both phorbol-12-myristate-13-acetate, a potent protein kinase C activator, and thapsigargin, which increases intracellular calcium levels, significantly increased both the Na+/H+ exchanger activity and HSC proliferation rate. Inhibition of the protein kinase A pathway did not modify either PDGF-induced Na+/H+ exchange activation or PDGF-induced HSC proliferation. On the contrary, inhibition of the mitogen-activated protein kinase- and of phosphatidylinositol 3-kinase-dependent pathways significantly reduced PDGF-induced HSC proliferation without affecting the activity of the Na+/H+ exchanger.

CONCLUSIONS

Activation of the Na+/H+ exchanger by PDGF in HSCs is mediated by calcium/calmodulin- and protein kinase C-dependent pathways. PDGF-induced HSC proliferation is mediated by Na+/H+ exchange-dependent and -independent pathways.

Characterization of ion transport mechanisms regulating intracellular pH in hepatic stellate cells

The aim of this study was to evaluate intracellular pH (pHi) regulation in nonactivated and activated rat hepatic stellate cells (HSC). The fluorescent pHi indicator 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein was used to measure pHi in the presence and absence of HCO3-. In the absence of HCO3-, baseline pHi was significantly higher (P < 0.001) in activated than in nonactivated HSC (7.1 +/- 0.1 vs. 6.9 +/- 0.2) and decreased, in both groups, after amiloride administration and after Na+ removal. After an acid-loading maneuver, pHi recovery was significantly higher (P < 0.03) in activated than in nonactivated HSC (H+ flux = 11.0 +/- 3.8 vs. 7.7 +/- 2.9 mM/min at pHi 6.6) and was inhibited by amiloride and Na+ removal. In the presence of HCO3-, baseline pHi was higher in both groups and decreased after amiloride administration. Amiloride and Na+ removal inhibited pHi recovery after an intracellular acid load by 77 and 93%, respectively, in nonactivated and by 82 and 92%, respectively, in activated HSC, whereas 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid inhibited pHi recovery by only 27%. Acute Cl- removal increased pHi by 0.07 +/- 0.01 pH unit/min in the absence but not in the presence of 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid in nonactivated and activated HSC in an Na(+)-independent manner. In activated HSC, 24 h of incubation with 25 ng/ml platelet-derived growth factor (PDGF)-BB (in 0.5% serum) did not modify baseline pHi (7.07 +/- 0.1 vs. 7.08 +/- 0.1 in HSC cultured in 0.5% serum only) but significantly (P < 0.02) increased, with respect to controls, pHi recovery after an acute acid load. Incubation with PDGF for 24 h induced a fivefold increase in HSC proliferation expressed as percentage of bromodeoxyuridine-positive cells (30.8 +/- 6.7 vs. 6.1 +/- 1.9% in controls). When amiloride (0.1 mM) was present, PDGF-induced HSC proliferation was significantly inhibited (8.1 +/- 0.4%, P < 0.001). Our results show that 1) the Na+/H+ exchanger is the main pHi regulator in rat HSC, 2) activation of HSC is associated with an increase in pHi and in the activity of the Na+/H+ exchanger, 3) PDGF increases the activity of this exchanger, and 4) amiloride is able to inhibit HSC proliferation induced by PDGF.