Role of the endothelial-to-mesenchymal transition in renal fibrosis of chronic kidney disease

All types of progressive chronic kidney disease (CKD) inevitably induce renal fibrosis, the hallmark of which is the activation and accumulation of a large number of matrix-producing fibroblasts or myofibroblasts. The activated fibroblasts or myofibroblasts are derived from diverse origins, such as residential fibroblasts, vascular pericytes, epithelial-to-mesenchymal transition (EMT), and bone marrow (circulating fibrocytes). Recently, endothelial-to-mesenchymal transition (EndMT) or endothelial-to-myofibroblast transition has also been suggested to promote fibrosis and is recognized as a novel mechanism for the generation of myofibroblasts. Similar to EMT, during EndMT, endothelial cells lose their adhesion and apical–basal polarity to form highly invasive, migratory, spindle-shaped, elongated mesenchymal cells. More importantly, biochemical changes accompany these distinct changes in cell polarity and morphology, including the decreased expression of endothelial markers and the acquisition of mesenchymal markers. This review highlights evidence supporting the important role of EndMT in the development of renal fibrosis in CKD and its underlying mechanisms, including novel biological significance of microRNA regulation.     

Low-Protein Diet for Diabetic Nephropathy

Diabetic nephropathy is the leading cause of progressive kidney disease, leading to end-stage renal disease and renal replacement therapy. Angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers have been considered effective at slowing the progression of kidney function deterioration. However, these drugs cannot sufficiently halt the progression of nephropathy to the extent that is required. A low-protein diet (LPD) is believed to be a nutritional intervention that may slow kidney disease progression. In fact, preclinical animal experiments have demonstrated excellent renoprotective effects of an LPD. However, in human clinical trials, analyses of the effects of protein restriction on diabetic nephropathy have not yet revealed consistently positive outcomes of this nutritional intervention. In this review, we analyze the potential renoprotective effects of an LPD on diabetic nephropathy and summarize the outcomes of clinical trials that have systematically investigated the efficacy of an LPD in diabetic nephropathy. In addition, we discuss some potential approaches associated with nutritional interventions to combat progressive kidney disease.     

Role of the spleen in liver fibrosis in rats may be mediated by transforming growth factor beta-1

BACKGROUND: The effect of the spleen on the cirrhotic liver is unknown. Transforming growth factor-beta 1 (TGF-beta 1), which plays a crucial role in the matrix production during liver fibrosis, is an inhibitory factor regarding the regeneration of hepatocytes. In this study, we investigated the TGF-beta 1 production in the spleen of cirrhotic rats and the effects of a splenectomy on the healing process from liver fibrosis. METHODS: Thirty-six Wistar male rats were used. Thioacetamide (TAA) was administered intraperitoneally for 24 weeks. The rats underwent either a sham operation (TAA + Sham) or a splenectomy (TAA + SPL). The improvements in liver fibrosis and liver regeneration were investigated 10, 30 and 60 days after the operations in each group. The effect of a splenectomy on the plasma concentration of TGF-beta 1 in the portal vein was investigated by ELISA. The TGF-beta 1 expressions in the spleen were measured using immunohistochemical staining and the degree of such expression was measured using RT-PCR. The activity of TGF-beta 1 in the portal vein of TAA + Sham and TAA + SPL was assessed by the inhibiting effect of rat parenchymal hepatocyte proliferation in primary culture. RESULTS: Liver regeneration (PCNA-labeling index) in the TAA + SPL rats was stimulated more at 10 and 30 days after the operation (P < 0.05) than in the TAA + Sham rats, and the improvement of liver fibrosis (fibrosis rate) in the TAA + SPL rats was higher at 60 days (P < 0.05) than in the TAA + Sham rats. The plasma concentration of TGF-beta1 of the portal vein in TAA + SPL rats was significantly lower than in the TAA + Sham rats for each period. Immunohistochemically, TGF-beta1-positive stained cells were recognized in the spleen macrophages in the red pulp of cirrhotic rats. The plasma of the TAA + Sham rats at 10 and 30 days after the operation was significantly stronger than that of the TAA + SPL rats in inhibiting the proliferation of rat hepatocytes of primary culture. Inhibitory effects were then dose-dependently neutralized by monoclonal TGF-beta 1 antibody. CONCLUSION: Spleen-derived TGF-beta 1 may thus play an inhibitory role in the healing of liver cirrhosis by inhibiting the regeneration of the damaged liver.     

Matrix Metalloproteinases in the Pathogenesis of Asthma and COPD

While asthma is an inflammatory disorder of the airways involving mediators released from mast cells and eosinophils, inflammation alone is insufficient to explain the chronic nature of the disease. Recent progress in the understanding of disease pathogenesis has revealed that airway remodeling, which is at least in part due to an excess of extracellular matrix (ECM) deposition in the airway wall, plays a significant role in airflow obstruction. Matrix metalloproteinases (MMPs) have been suggested to be the major proteolytic enzymes to induce airway remodeling in asthma and COPD. It has been widely accepted that different inflammatory processes are involved in asthma and COPD with different inflammatory cells, mediators, and responses to treatments. Despite these different processes, airflow obstruction and airway remodeling characterize these two diseases. MMP-2 and -9 have been reported to be involved in the pathogenesis of airway remodeling in both diseases and MMP-12, in addition to these MMPs, in the pathogenesis of COPD. In this review, we discuss the current views on the role of MMPs in the pathogenesis of bronchial asthma and COPD. Anti-MMP therapy could theoretically be useful to prevent airway remodeling in asthma and COPD. However, to date no clinical data are available regarding the efficacy of anti-MMP therapies in the treatment of patients with asthma and COPD.     

Angiogenesis in hepatocellular carcinoma as evaluated by CD34 immunohistochemistry

ABSTRACT— To clarify the relationship between angiogenesis and hepatocarcinogenesis on progression of hepatocellular carcinoma (HCC), we quantitatively evaluated angiogenesis by CD34 immunohistochemistry in liver cirrhosis (LC), adenomatous hyperplasia (AH), and HCC, and proliferative activity estimated by Ki-67 immunohistochemistry. Angiogenesis was evaluated by CD34 immunohistochemistry using monoclonal antibody HPCA-2, and tumor proliferative activity was evaluated using monoclonal antibody MIB-1. We used an image analysis system to assess the microvessel density as the area percentage of the endothelial area. Angiogenesis was generally observed in HCC and there was no significant difference among all clinical stages and histological grades of HCC. On the other hand, the staining of CD34 was partly observed in sinusoids of AH, although no positive staining was seen in any sinusoids of LC. The proliferative activity was significantly correlated with the clinical stage and histological grade of HCC. Our results indicate that the quantitation of angiogenesis does not provide significant prognostic information in HCC, but that it may have diagnostic value in distinguishing HCC from non-HCC. Meanwhile, AH, which is not morphologically diagnosed as cancer, shows positive staining for CD34, suggesting that some portion of AH contains cancerous characteristics.     

Prognostic significance of natural killer cell activity in patients with gastric carcinoma: a multivariate analysis

OBJECTIVE: Natural cytotoxicity, mediated by natural killer (NK) cells, has been believed to play an important role in inhibiting experimental tumor metastasis, and diminished NK cell activities leads to a high incidence of tumor occurrence. Despite convincing evidence from experimental studies, the role of NK cells in the immunological surveillance against cancer in human is poorly defined. METHODS: The present study was based on a retrospective analysis of data on 156 patients with gastric cancer, who were surgically treated in the Department of Surgery II, Kyushu University Hospital from 1993 to 1996. All patients were examined for NK cell activity based on a peripheral blood sampling done preoperatively. RESULTS: Significant association between NK cell activity and clinicopathological parameters including tumor size, lymphatic involvement, vascular involvement, and lymph node metastases was evident. When comparing the two groups according to NK cell activity, tumors with low NK cell activity tend to have lymphatic involvement. The 5-yr survival rates were 94.6% and 72.3% for those with NK cell activity > 25% lysis and < or = 25% lysis, respectively, the value being statistically significant (p < 0.05). The independent risk factors for prognosis examined by logistic regression analysis were lymphatic involvement. NK cell activity, depth of tumor invasion, and lymph node dissection. CONCLUSIONS: These current data showed that NK cell activity may be related to tumor volume and dissemination. Measurement of preoperative NK cell activity may be pertinent for the prognosis of patients with gastric cancer and for follow-up clinical management.