Biomedical subjects

Ichiro Hirahara

Publications and source records attributed to Ichiro Hirahara.

8 recordsLinked to original sources

PubMed2006

The potential of matrix metalloproteinase-2 as a marker of peritoneal injury, increased solute transport, or progression to encapsulating peritoneal sclerosis during peritoneal dialysis--a multicentre study in Japan.

BACKGROUND: Long-term peritoneal dialysis (PD) leads to peritoneal injury. At worst, peritoneal injury leads to encapsulating peritoneal sclerosis (EPS), which is a serious complication of PD. The mortality rate of EPS is extremely high. To perform PD safely, monitoring of peritoneal injury that leads to EPS is a necessity. METHODS: A total of 444 PD patients with end-stage renal disease at 60 centres in Japan were analysed (sex, 54% males; median age, 56 years; median PD duration, 55 months). Matrix metalloproteinase (MMP)-2 and MMP-9 in the peritoneal effluents were analysed with gelatin zymography or enzyme-linked immunosorbent assay. Cells expressing MMP-2 in the peritoneal tissue were investigated immunohistologically with anti-MMP-2 antibodies. Peritoneal solute transport was assessed with the peritoneal equilibration test (PET). RESULTS: The MMP-2 levels in peritoneal effluents obtained with the PET were significantly correlated with the D/P Cr ratio (R = 0.69, P < 0.001) and the D/D0 glucose ratio (R = -0.59, P < 0.001). The MMP-2 levels in patients with mild peritoneal injury, moderate peritoneal injury, severe peritoneal injury (EPS) and infectious peritonitis were significantly higher than those in control patients (P < 0.001, P < 0.001, P < 0.01 and P < 0.05, respectively). MMP-2 was produced by myofibroblast-like mesenchymal cells and macrophages in the peritoneum. The peritoneal effluents from patients with infectious peritonitis showed strong MMP-9 signals. CONCLUSIONS: From these results, MMP-2 levels in peritoneal effluents reflect peritoneal solute transport and changes in MMP-2 levels are associated with peritoneal injury that leads to EPS. MMP-2 may be a useful marker of peritoneal injury, increased solute transport or progression to EPS.

Aged↗

PubMed2005

A case of encapsulating peritoneal sclerosis at the clinical early stage with high concentration of matrix metalloproteinase-2 in peritoneal effluent.

In encapsulating peritoneal sclerosis (EPS), matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases are involved in the remodeling of peritoneal tissue. We measured the MMP-2 concentration in the peritoneal effluents of a patient with EPS who discontinued continuous ambulatory peritoneal dialysis (CAPD) therapy because of ultrafiltration failure and/or underdialysis. First, we report a 58-year-old female patient who discontinued CAPD therapy because of underdialysis. Several months after cessation of CAPD, she complained of slightly blood-colored ascites and had an elevated level of C-reactive protein (CRP) in plasma. She was diagnosed as having clinical early-stage EPS. Peritoneal effluents drained from this case, and from 11 patients who discontinued CAPD therapy because of ultrafiltration failure and/or underdialysis, and who underwent peritoneal lavage with 1.5% dextrose peritoneal dialysis fluid for several months, were analyzed by gelatin zymography. MMP-2 concentration was also measured by enzyme-linked immunosorbent assay (ELISA). MMP-2 concentration in peritoneal effluent of this patient was highest compared with that of the other patients. There was some tendency of a positive correlation between MMP-2 concentration per 1 g protein and D/Pcr, and was negative correlation between MMP-2 concentration per 1 g of protein and D/D0 glucose. We concluded that MMP-2 is involved in the peritoneal remodeling of long-term CAPD therapy and the progression of EPS.

Ascitic Fluid↗

PubMed2004

Activation of matrix metalloproteinase-2 causes peritoneal injury during peritoneal dialysis in rats.

BACKGROUND: Sclerosing peritonitis (SP) and encapsulating peritoneal sclerosis (EPS) are serious complications of continuous ambulatory peritoneal dialysis. Although we have shown previously that matrix metalloproteinase-2 (MMP-2) is increased in peritoneal injury leading to SP/EPS, most of the MMP-2 in the dialysate drained from the peritoneal cavity was the latent form that was lacking activity. In the present study, we investigated whether MMP-2 causes peritoneal injury. METHODS: To create an animal model of peritoneal injury, we administered intraperitoneally chlorhexidine gluconate to rats. Dialysate drained from these rats was analysed by gelatin zymography and MMP-2 activity was analysed by an in situ film zymography method. In vitro myofibroblasts were cultured in collagen three-dimensional culture and then MMP-2 in conditioned medium from the culture was analysed by gelatin zymography. RESULTS: Zymographic analysis revealed that latent form MMP-2 levels were high in the dialysate from peritoneal injury rats, whereas the active form was barely detectable. MMP-2 activity in the peritoneal tissue of the peritoneal injury rats was strongly detected by in situ film zymography. In vitro myofibroblasts were promoted to produce MMP-2 and to activate MMP-2 in collagen three-dimensional culture. CONCLUSIONS: In the present model, most of the MMP-2 was in the latent form, but activation of MMP-2 was promoted in the peritoneum during peritoneal injury. Activated MMP-2 may be associated with the progression of peritoneal injury.

Animals↗

PubMed2004

Rapid, simple, and reliable method for the diagnosis of CAPD peritonitis using the new MMP-9 test kit.

The objective of the present study was to evaluate the sensitivity and efficiency of the matrix metalloproteinase-9 (MMP-9) test kit for the diagnosis of bacterial peritonitis in patients undergoing peritoneal dialysis (PD). Peritoneal effluents were collected from seven continuous ambulatory PD (CAPD) patients with peritonitis, four patients with suspected peritonitis, 30 maintenance PD patients without infection, and seven patients at initiation of PD. The MMP-9 test kit was used to analyze 112 peritoneal effluent samples. These peritoneal effluents were also used to count leukocytes and examine microorganisms. MMP expression was measured by gelatin zymography, and activities were measured by an enzyme-linked immunosorbent assay (ELISA). The relationship between the reactivity of the test kit and the number of leukocytes in the samples was examined. There was a significant difference in the number of leukocytes in peritoneal effluents between the negative and positive groups detected by the MMP-9 test kit (P < 0.0001). The results obtained with the MMP-9 test kit were negative for peritoneal effluent samples that did not show increased cell counts. The reactivity of the MMP-9 test kit showed no significant differences among various microorganisms, and remained stable. The MMP-9 test kit appears to be a simple and reliable method for early diagnosis of CAPD peritonitis, and reflects the leukocyte count in peritoneal effluents.

Adult↗

PubMed2004

Neutral-pH peritoneal dialysis solution improves peritoneal function and decreases matrix metalloproteinase-2 (MMP-2) in patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

BACKGROUND: Conventional lactate-buffered peritoneal dialysis (PD) solutions have several bioincompatible characteristics, including acidic pH, lactate buffer, and the presence of glucose degradation products (GDPs), and these characteristics contribute to membrane dysfunction in PD patients. The formation of GDPs can be reduced by separating the glucose component of the solution from the lactate component during sterilization. This study was carried out to evaluate the clinical effect of dual-chambered neutral-pH PD solution in patients on continuous ambulatory peritoneal dialysis (CAPD). METHODS: Thirteen CAPD patients using conventional PD solution were enrolled in this study. The fast peritoneal equilibration test (fast PET) was performed periodically before and after treatment with neutral PD solution. The concentration of matrix metalloproteinase-2 (MMP-2) in dialysate effluent was measured using 4-h dwelling 2.5% glucose dialysis solution. The patients were categorized into two groups, according to the value of the initial dialysate/plasma (D/P) creatinine ratio: i.e., lower transporters (group L, D/PCr < 0.65) and higher transporters (group H, D/PCr >/= 0.65). RESULTS: The mean D/P creatinine ratio measured by fast PET, was significantly decreased (0.72 +/- 0.09 to 0.60 +/- 0.06; P < 0.03) after treatment with neutral PD solution in group H. The mean glucose level in 4-h dwelling dialysate effluent was elevated (824.6 +/- 195.9 mg/dl to 942.6 +/- 147.8 mg/dl; P < 0.022) in all subjects. In group H, a significant decrease of MMP-2 in the dialysate effluent was recognized from 15 months after the beginning of treatment with the neutral PD solution (141.4 +/- 52.5 ng/ml to 91.3 +/- 15.1 ng/ml; P < 0.05), with the lowest value being shown at 21 months (80.0 +/- 31.8 ng/ml; P < 0.03). CONCLUSIONS: Neutral-pH peritoneal dialysis solution decreased the MMP-2 level in dialysate and improved peritoneal function in high-transporter patients with CAPD treatment.

Adult↗

PubMed2004

Morphologic changes of peritoneum and expression of VEGF in encapsulated peritoneal sclerosis rat models.

BACKGROUND: Simple sclerosis consisted of a thin layer of submesothelial sclerotic tissue in peritoneal dialysis patients. Encapsulated peritoneal sclerosis (EPS) was characterized by thick sclerotic tissue involving vascular alterations in peritoneal dialysis patients. The objective of the present study is to evaluate serial morphologic changes and expressions of angiogenic factors [i.e., vascular endothelial growth factor (VEGF), angiopietin-1 (Ang-1), and angiopoietin-2 (Ang-2)] in EPS rat models. METHODS: Twenty-four rats were given a daily intraperitoneal injection of chlorhexidine gluconate and ethanol dissolved in saline (CH). Nine rats were injected with CH and anti-VEGF neutralizing antibody simultaneously. Quantitative blood vessel evaluation was performed by staining for GS1-lectin. The mRNA expression of VEGF, Ang-1, Ang-2, and their receptors was evaluated by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). Immunohistochemical staining was performed in peritoneal vessels using anti-VEGF, Ang-1, and Ang-2 antibodies. Hematopoietic stem cells were detected using anti-CD34 antibody. RESULTS: The vessel area, diameter, and length gradually increased until day 21, and then decreased. VEGF and Ang-2 mRNA expressions gradually increased until day 35. In contrast, Ang-1 peaked at day 21 and then decreased significantly. VEGF blockade improved the experimental EPS. In immunohistochemistry, the vessels stained by VEGF and Ang-2 were detected in subfibrous layer. CD34-positive cells were markedly stained at day 21. CONCLUSION: Neoangiogenesis was observed in a rat model of experimental EPS. VEGF and angiopoietin/Tie system play an important role in the neoangiogenesis in this model. An analysis using this experimental rat model may elucidate the development of EPS in peritoneal dialysis patients.

Angiopoietin-1↗

PubMedDate not supplied

Peritoneal injury by methylglyoxal in peritoneal dialysis.

BACKGROUND: Peritonealdialysis (PD) is a common treatment for patients with reduced or absent renal function. Long-term PD leads to peritoneal injury with structural changes and functional decline, such as ultrafiltration loss. At worst, peritoneal injury leads to encapsulating peritoneal sclerosis, a serious complication of PD. Glucose degradation products contained in PD fluids contribute to the bioincompatibility of conventional PD fluids. Methylglyoxal (MGO) is an extremely toxic glucose degradation product. The present study examined the injurious effect of MGO on peritoneum in vivo. METHODS: Male Sprague-Dawley rats (n = 6) were administered PD fluids (pH 5.0) containing 0, 0.66, 2, 6.6, or 20 mmol/L MGO every day for 21 days. On day 22, peritoneal function was estimated by the peritoneal equilibration test. Drained dialysate was analyzed for type IV collagen-7S, matrix metalloproteinase (MMP), and vascular endothelial growth factor (VEGF). Histological analysis was also performed. RESULTS: In rats receiving PD fluids containing more than 0.66 mmol/L MGO, peritoneal function decreased significantly and levels of type IV collagen-7S and MMP-2 in drained dialysate increased significantly. In the 20-mmol/L MGO-treated rats, loss of body weight, expression of VEGF, thickening of the peritoneum, and formation of abdominal cocoon were induced. MMP-2 and VEGF were produced by infiltrating cells in the peritoneum. Type IV collagen was detected in basement membrane of microvessels. CONCLUSION: MGO induced not only peritoneal injury but also abdominal cocoon formation in vivo. The decline of peritoneal function may result from reconstitution of microvessel basement membrane or neovascularization.

Animals↗

PubMedDate not supplied

Endothelin(B) receptor blocker inhibits high glucose-induced synthesis of fibronectin in human peritoneal mesothelial cells.

BACKGROUND: Long-term peritoneal dialysis using glucose-based dialysates is associated with peritoneal fibrosis. The object of this study was to investigate the hypothesis that endothelin (ET)-1, which is known to play an important role in various fibrotic diseases, may also be involved in peritoneal fibrosis using human peritoneal mesothelial cells (HPMC). METHODS: HPMC were cultured with 4% D- or L-glucose, or loaded with 10 nmol/L ET-1. In some experiments, the ETA receptor antagonist BQ-123, the ETB receptor antagonist BQ-788, and antioxidants 4-hydroxy-2,2,6,6-tetramethyl-piperidine 1-oxyl (TEMPOL) and diphenyleneiodium chloride (DPI) were used. mRNA expression of ET-1, ETA receptor, ETB receptor, and fibronectin (FN) was analyzed by real-time polymerase chain reaction (real-time PCR). The protein levels for FN and ET-1 were measured by ELISA. CM-H2DCFDA-sensitive reactive oxygen species (ROS) were evaluated by flow cytometry. RESULTS: D-Glucose significantly induced mRNA expression of ET-1 and the ETB receptor but not the ETA receptor. FN production under high glucose conditions was inhibited by BQ-788. ET-1 directly stimulated H PMC to increase mRNA expression of FN and CM-H2DCFDA-sensitive ROS production. BQ-788, TEMPOL, and DPI inhibited mRNA expression of FN induced by ET-1. CONCLUSION: The present study suggests that high-glucose-induced FN synthesis is mediated by the ET-1/ETB receptor pathway and, therefore, an ETB receptor antagonist may be usefulin preventing FN production in HPMC.

Aspartic Acid Endopeptidases↗