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Takatoshi Maeno

Publications and source records attributed to Takatoshi Maeno.

4 recordsLinked to original sources
PubMed2006

Correlation between angiotensin-converting enzyme, vascular endothelial growth factor, and matrix metalloproteinase-9 in the vitreous of eyes with diabetic retinopathy.

PURPOSE: To investigate the involvement of angiotensin-converting enzyme (ACE) with angiogenic factors, vascular endothelial growth factor (VEGF), and matrix metalloproteinase (MMP)-9 in the vitreous of eyes with proliferative diabetic retinopathy (PDR). DESIGN: Observational case series. METHODS: Angiotensin-converting enzyme activity in the vitreous was measured by using a synthetic substrate for ACE. VEGF and MMP-9 concentrations were determined by enzyme-linked immunosorbent assay. RESULTS: Vitreous ACE activity was significantly higher in eyes with PDR (1.4 +/- 1.3 mU/ml) than in eyes with macular holes (0.22 +/- 0.11 mU/ml). Vitreous VEGF concentration in the eyes with PDR (1067 +/- 1076 pg/ml) was significantly higher than in eyes with macular holes (34 +/- 5.5 pg/ml). Vitreous MMP-9 concentration was also significantly higher in eyes with PDR (7.5 +/- 3.8 ng/ml) than in eyes with macular holes (4.2 +/- 1.4 ng/ml). Significant correlations between ACE and VEGF (P < .01) and between ACE and MMP-9 (P < .01) were observed in the vitreous of eyes with PDR. CONCLUSIONS: Angiotensin-converting enzyme was significantly correlated with angiogenic factors, VEGF and MMP-9, in the vitreous of eyes with PDR.

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PubMed2006

Islet-like cell clusters: viability, cell types, and subretinal transplantation in pancreatectomized cats.

We investigated a method for isolating sufficient feline islets of Langerhans to restore normoglycaemia following transplantation into the subretinal space of pancreatectomized cats. Collagenase digestate of feline pancreas was maintained in serum-free tissue culture medium for 1-9 days. Viability of islet-like cell clusters (ICC) was assessed with ethidium bromide and fluorescein diacetate staining; cell types were identified immunohistochemically. After nine days, the ICC were transplanted. We estimated viable ICC in tissue culture at nine days as 3800 +/- 2000 (mean +/- SD) per pancreas. While numbers of beta cells decreased over time in culture, ductal cells increased. Bromodeoxyuridine labelling showed no proliferation of beta cells but extensive proliferation of ductal cells. Subretinal transplants of cultured ICC in the diabetic cats maintained normoglycaemia for up to 12 days, while they provoked massive lymphocyte infiltration indicating rejection. Islet transplantation into the feline subretinal space temporarily restored normoglycaemia. Our current method of culture achieved sufficient reduction of acinar cells but an insufficient yield of insulin-producing cells.

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PubMedDate not supplied

Survival of subretinal pancreatic islet cell allografts and apoptosis in infiltrating lymphocytes in rats.

Survival of pancreatic islet cells transplanted into the subretinal space in rat eyes was studied in relation with apoptosis of infiltrating lymphocytes. Islets isolated from inbred DA rats were transplanted into the subretinal space of fully MHC-mismatched Lewis rats. Syngeneic subretinal transplants and allogeneic subretinal transplants from Sprague-Dawley (SD) rats were performed as controls. From 7 to 60 days after transplantation, immunoperoxidase staining for insulin, glucagon, CD4, CD8, and interleukin (IL)-2, and evaluation of apoptosis using nick-end labeling (TUNEL) were performed. Fully MHC-mismatched grafts were rejected by day 14, showing massive infiltration by CD4+, CD8+, and IL-2+ lymphocytes. Syngeneic transplants and allografts in SD rats survived up to 60 days without appreciable lymphocytic infiltration. Endocrine cells were the major component of surviving transplanted tissue. No difference in distribution of TUNEL+ cells was seen between syngeneic transplants and subretinal allografts in SD rats on day 60. A few TUNEL+ CD8+ lymphocytes were found in rejected MHC-mismatched transplants, but apoptotic lymphocytes were not seen in surviving or syngeneic grafts. Pancreatic islet survival in the subretinal space is MHC dependent. Accumulation of infiltrating lymphocytes may be suppressed by a modified immune response.

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