Noritoshi Kobayashi

FOXP3+ regulatory T cells affect the development and progression of hepatocarcinogenesis

Purpose: Tumor-infiltrating lymphocytes represent the host immune response to cancer. CD4+CD25+FOXP3+ regulatory T cells (Tregs) suppress the immune reaction. The aim of the present study was to investigate the clinicopathologic significance and roles of Tregs and CD8+ T cells during hepatocarcinogenesis. Experimental Design: We examined the infiltration of FOXP3+ Tregs and CD8+ T cells in the tumor stroma and nontumorous liver parenchyma using 323 hepatic nodules including precursor lesions, early hepatocellular carcinoma (HCC), and advanced HCC, along with 39 intrahepatic cholangiocarcinomas and 59 metastatic liver adenocarcinomas. We did immunohistochemical comparative studies. Results: The prevalence of Tregs was significantly higher in HCC than in the nontumorous liver (P < 0.001). The patient group with a high prevalence of Tregs infiltrating HCC showed a significantly lower survival rate (P = 0.007). Multivariate analysis revealed that the prevalence of Tregs infiltrating HCC was an independent prognostic factor. The prevalence of Tregs increased in a stepwise manner (P < 0.001) and that of CD8+ T cells decreased during the progression of hepatocarcinogenesis (P < 0.001). Regardless of the presence of hepatitis virus infection or histopathologic evidence of hepatitis, the prevalence of Tregs was significantly increased in nontumorous liver bearing primary hepatic tumors. Conclusions: Tregs play a role in controlling the immune response to HCC during the progression of hepatocarcinogenesis. It has been suggested that primary hepatic cancers develop in liver that is immunosuppressed by a marked infiltration of Tregs. A high prevalence of Tregs infiltrating HCC is thought to be an unfavorable prognostic indicator.

Dysfunctional very-low-density lipoprotein synthesis and release is a key factor in nonalcoholic steatohepatitis pathogenesis†‡

The specific mechanisms of nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH) pathogenesis remain unknown. In the present study we investigated the differences between NAFL and NASH in terms of liver lipid metabolites and serum lipoprotein. In all, 104 Japanese subjects (50 men and 54 postmenopausal women) with histologically verified NAFL disease (NAFLD) (51 with NAFL, 53 with NASH) were evaluated; all diagnoses were based on liver biopsy findings and the proposed diagnostic criteria. To investigate the differences between NAFL and NASH in humans, we carefully examined (1) lipid inflow in the liver, (2) lipid outflow from the liver, (3) very‐low‐density lipoprotein (VLDL) synthesis in the liver, (4) triglyceride (TG) metabolites in the liver, and (5) lipid changes and oxidative DNA damage. Most of the hepatic lipid metabolite profiles were similar in the NAFL and NASH groups. However, VLDL synthesis and lipid outflow from the liver were impaired, and surplus TGs might have been produced as a result of lipid oxidation and oxidative DNA damage in the NASH group. Conclusion: A growing body of literature suggests that a deterioration in fatty acid oxidation and VLDL secretion from the liver, caused by the impediment of VLDL synthesis, might induce serious lipid oxidation and DNA oxidative damage, impacting the degree of liver injury and thereby contributing to the progression of NASH. Therefore, dysfunctional VLDL synthesis and release may be a key factor in progression to NASH. (HEPATOLOGY 2009.)

Association between angiotensin II type 1 receptor polymorphisms and the occurrence of nonalcoholic fatty liver disease.

Background: Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver injury in many countries. Genetic factors are important for the development of NAFLD, as well as environmental factors. Recently an angiotensin II type 1 receptor (AGTR1) has been recognized as important in the aetiology of fibrosis in the liver.

Incidence of Small Bowel Injury Induced by Low-Dose Aspirin: A Crossover Study Using Capsule Endoscopy in Healthy Volunteers

Background and Aims: Small intestinal toxicity of low-dose aspirin remains unclear. The purpose of this capsule endoscopy study was to assess the incidence of small bowel injury in healthy volunteers treated with short-term low-dose aspirin. Methods: Healthy subjects were randomly assigned to receive low-dose aspirin for 14 days (Aspirin group) or no drugs for 14 days (Control group). The two treatment occasions were separated by a washout period of at least 4 weeks. All subjects underwent capsule endoscopy at the end of each treatment period. Results: After 2 weeks of treatment, the percentages of subjects with small bowel pathology were 80% in the Aspirin group compared with 20% in the Control group (p = 0.023). The incidence of small bowel mucosal breaks in the Aspirin group was higher than that in the Control group, although the difference was not significant (30 vs. 0%; p = 0.210). Conclusions: This is the first pilot study using capsule endoscopy to report on the relation between small bowel injury and low-dose aspirin. Among the healthy subjects, the short-term administration of low-dose aspirin was associated with a mild mucosal inflammation of the small bowel.

Prognostic Value of Tumor Architecture, Tumor-Associated Vascular Characteristics, and Expression of Angiogenic Molecules in Pancreatic Endocrine Tumors

Purpose: It is difficult to predict the biological behavior of pancreatic endocrine tumors (PETs). Our aim was to evaluate the prognostic significance of certain variables in PETs. Experimental Design: The following variables were examined in 37 patients with PETs and then compared with other clinicopathologic characteristics: histologic tumor structure; microvessel density (MVD) measured by three different methods, including a unique method involving calculation of solid area MVD; endothelial proliferation; and the immunohistochemical expression of vascular endothelial growth factor-A and CXC chemokine CXCL-12. Intratumoral vascular structures were analyzed by double immunofluorescence using 30-μm-thick sections. Results: The presence of focal and intensive solid growth of tumor cells (large solid nests; P = 0.003), low solid area MVD (P = 0.002), a high endothelial cell proliferation index (EPI; P = 0.005), and high expression of CXCL-12 in PET cells (P = 0.018) were significant unfavorable prognostic indicators. The predominant structure of the overall tumor histology and the expression of vascular endothelial growth factor-A did not separate aggressive PETs. In areas of focal solid growth, tumor-associated blood vessels had obviously low MVD and high EPI, and their structures were poorly formed with highly abnormal features, in comparison with other areas. High expression of CXCL-12 in tumor cells was significantly associated with variables representing tumor growth, hematogenous tumor spread, low MVD, high EPI, and the presence of large solid nests. Conclusions: This study has provided novel findings on the prognostic features of tumor architecture and tumor-associated angiogenesis in PETs. CXCL-12 is the first candidate molecule in association with neoangiogenesis in PETs.

Effectiveness of antiplatelet drugs against experimental non-alcoholic fatty liver disease

Objective: No effective drugs have been developed to date to prevent or treat non-alcoholic fatty liver disease (NAFLD), although diet modification and exercise to improve obesity have been attempted. Therefore, development of a novel drug/strategy to treat NAFLD is urgently needed. In the present study, a novel concept is proposed for the treatment of NAFLD. Methods: Fisher 344 male rats were given a choline-deficient, l-amino acid-defined (CDAA) diet or a high-fat high-calorie (HF/HC) diet with or without the antiplatelet agents, aspirin, ticlopidine or cilostazol for 16 weeks. Liver steatosis, inflammation and fibrosis, and the possible mechanisms involved were investigated. Results: All three antiplatelet drugs, namely aspirin, ticlopidine and cilostazol, significantly attenuated liver steatosis, inflammation and fibrosis in the CDAA diet group. Of the three agents, cilostazol was the most effective, and the drug also suppressed HF/HC diet-induced liver steatosis. Cilostazol appeared to exert its beneficial effect against NAFLD by suppressing mitogen-activated protein kinase activation induced by oxidative stress and platelet-derived growth factor via intercepting signal transduction from Akt to c-Raf. Conclusion: Antiplatelet agents, especially cilostazol, offer the promise of becoming key agents for the treatment of NAFLD.

Contrast-enhanced sonography of pancreatic carcinoma: correlations with pathological findings

BackgroundWe examined contrast-enhanced harmonic gray-scale sonographic findings of pancreatic carcinoma in relation to the pathological findings in resected specimens to evaluate correlations between observations made by this modality and the pathological findings.MethodsThe pathological findings of surgical specimens obtained from 16 patients were examined in relation to the contrast-enhanced harmonic gray-scale sonography findings. Lesion vascularity was examined by contrast-enhanced harmonic gray-scale sonography from 20 to 50 s after the injection of Levovist (Schering, Berlin, Germany) (early phase), and lesion enhancement was also monitored at approximately 90 s after injection (delayed phase).ResultsContrast-enhanced harmonic gray-scale sonography showed positive enhancement in 12 of the 16 lesions (peripheral tumor region alone, n = 9; entire tumor, n = 3), while the other 4 lesions showed no contrast enhancement in any region. Twelve enhanced regions (9 peripheral tumor region and 3 entire tumor regions) detected by contrast-enhanced harmonic gray-scale sonography showed: (1) mild fibrosis with inflammation, in 10 regions (83%); (2) the presence of both carcinoma cells and residual acinar cells in 8 (67%); and (3) presence of relatively large arteries in 2 (17%). In contrast, 13 non-enhanced regions (4 entire tumor regions and 9 central regions) showed: (1) severe fibrosis in 10 regions (77%); (2) necrosis in 7 (54%); and (3) mucin in 4 (31%).ConclusionsContrast-enhanced harmonic gray-scale sonographic findings of pancreatic carcinoma are influenced by interstitial histological features associated with tumor growth.

Association between PPARGC1A polymorphisms and the occurrence of nonalcoholic fatty liver disease (NAFLD)

BackgroundGenetic factors as well as environmental factors are important in the development of NAFLD and in this study we investigated associations between polymorphisms of peroxisome proliferators-activated receptor γ coactivator 1α polymorphism (PPARGC1A) and NAFLD.AimsWe recruited 115 patients with biopsy-proven NAFLD, 65 with NASH and 50 with simple steatosis, and 441 healthy control subjects and investigated 15 SNPs of PPARGC1A.ResultsSNP rs2290602 had the lowest p value in the dominant mode (p = 0.00095), and the odds ratio for NAFLD (95% CI) was 2.73 (1.48 – 5.06). rs2290602 was significantly associated with NAFLD even when the most conservative Bonferronis correction was applied (p = 0.0143). The frequency of the T allele of rs2290602 was significantly higher in the NASH patients than in the control subjects (p = 0.00093, allele frequency mode), and its frequency in the NASH patients tended to be higher than in the simple steatosis patients (p = 0.09). The results of the real-time RT-PCR study showed that intrahepatic mRNA expression of PPARGC1A was lower in the TT group than in the GG or GT group at SNP rs2290602 (p = 0.0454).ConclusionThis is the first study to demonstrate a significant association between genetic variations in PPARGC1A and NAFLD. This finding suggested that PPARGC1A polymorphism and lower expression of PPARGC1A mRNA in the liver are an important genetic contribution to etiology of NAFLD.

Plasma Pentraxin3 is a Novel Marker for Nonalcoholic Steatohepatitis (NASH)

BackgroundThe changes in the liver in nonalcoholic fatty liver disease (NAFLD) range over a wide spectrum, extending from steatosis to steatohepatitis (NASH). However it has remained difficult to differentiate between NASH and non-progressive NAFLD on the basis of the clinical findings alone.AimsIn this study we investigated the clinical usefulness of plasma Pentraxin3 (PTX3) levels to predict NASH. Plasma PTX3 was measured in 70 patients with histologically verified NAFLD (28 with non-NASH and 42 with NASH) and 10 healthy control subjects.ResultsThe plasma PTX3 level was significantly higher in the NASH cases than in the non-NASH cases (p = 0.0021) and control subjects (p = 0.045). And the plasma PTX3 level was significantly higher in the stages 3–4 NAFLD cases than in the stages 0–2 NAFLD cases (p < 0.0001). The PTX3 values were closely correlated with the stages of liver fibrosis (p < 0.0001, Kruskal-Wallis test). To detect NASH compared with non-NASH, the area under the curve for plasma PTX3 were 0.755, and to detect stages 3–4 NAFLD compared with stages 0–2 NAFLD, the area under the curve for plasma PTX3 were 0.850.ConclusionThis is the first study to demonstrate consistent and profound elevation of plasma PTX3 levels in NASH in comparison with non-NASH. The results suggest that plasma PTX3 levels may not only be laboratory values that differentiate NASH from non-NASH, but marker of the severity of hepatic fibrosis in NASH.

Contrast-Enhanced Sonography of Autoimmune Pancreatitis Comparison With Pathologic Findings

Objective. We evaluated the vascularity of autoimmune pancreatitis lesions on contrast‐enhanced harmonic gray scale sonographic images in comparison with the pathologic findings. Methods. Six patients with autoimmune pancreatitis were examined. All patients held their breath from 20 to 50 seconds after the injection of a contrast agent while the vascularity of the lesion was examined by contrast‐enhanced harmonic gray scale sonography (early phase), and lesion enhancement was monitored at about 90 seconds after the injection while the patients held their breath for a few seconds (delayed phase). We then compared the vascularity on the contrast‐enhanced harmonic gray scale sonographic images with the pathologic findings (fibrosis and inflammation) in all lesions. The vascularity of 3 of the 6 lesions was also evaluated by contrast‐enhanced harmonic gray scale sonography before and after treatment with corticosteroids. Results. The autoimmune pancreatitis lesions exhibited mild (n = 1), moderate (n = 3), or marked (n = 2) enhancement throughout almost the entire lesions in both the early and delayed phases. The grade of lesion vascularity on the contrast‐enhanced harmonic gray scale sonographic images correlated with the pathologic grade of inflammation and inversely correlated with the grade of fibrosis associated with autoimmune pancreatitis. The vascularity of all 3 lesions had decreased on the contrast‐enhanced harmonic gray scale sonographic images after steroid therapy. Conclusions. Contrast‐enhanced harmonic gray scale sonography may be useful for evaluating the vascularity of autoimmune pancreatitis lesions and the therapeutic efficacy of steroid therapy.