Shigehisa Aoki

A new organotypic culture of thyroid tissue maintains three-dimensional follicles with C cells for a long term

Thyroid follicles embedded in extracellular matrix (ECM) seem to be supplied enough oxygen by a dense network of capillaries in vivo. Air exposure (AE) causes cells to increase oxygen availability in vitro. We speculated that three-dimensional (3D) environment of ECM together with AE may be applied to a thyroid tissue-organotypic culture, simply simulating such a microenvironment of follicles. To address the issue, we performed 3D collagen gel culture of minced thyroid tissues with or without AE. Most follicles in the tissues without AE died within 7 days. In culture with AE, most of the follicles with calcitonin-positive C cells were kept for over one month. Immunohistochemistry showed that thyrocytes displayed thyroglobulin, thyrotropin receptor, thyroid transcription factor-1 (TTF-1), and pendrin, which are all crucial for thyroid function. C cells expressed calcitonin gene-related peptide and TTF-1. Our study is the first demonstration that 3D collagen gel culture with AE retains 3D thyroid follicles with C cells for a long term. This suggests that ECM and oxygen supply together may be crucial for maintenance of 3D follicle structure and function. Our method will possibly open a new path to the study of thyrocyte-C cell interaction and thyroid biology.

Different Effects of Castration and Estrogen Administration on Glomerular Injury in Spontaneously Hyperglycemic Otsuka Long-Evans Tokushima Fatty (OLETF) Rats

Aim: Non-insulin-dependent diabetic mellitus model rats, Otsuka-Long-Evans-Tokushima-Fatty (OLETF), develop diabetic nephropathy presenting with mesangial expansion leading to glomerular sclerosis and thickening of the glomerular basement membrane (GBM), especially in elderly males. The effects of sex hormones and castration on the incidence of diabetes mellitus (DM) have been studied in this strain rat. However, there have been no detailed studies on the effects of castration and sex hormone in the development of diabetic nephropathy. Methods: In this study we examine the effect of castration or estrogen on the development of glomerular injury in OLETF rats. Thirty male OLETF rats and 10 male long-Evans Tokushima Otsuka (LETO) rats as a normal control were used. OLETF rats were divided into three groups: group 1 received sham-operation, group 2 was castrated at 6 weeks, and group 3 was administered 0.1 mg estrogen subcutaneously once a month from 6 weeks to 58 weeks of age and LETO rats were assigned to group 4. Body weight, urinary protein and fasting blood glucose, serum albumin and other serum constituents were investigated every 12 weeks from 12 weeks to 60 weeks of age. In groups 1–3, glucose tolerance test was performed at 38 weeks. Each group was studied morphologically at the end of the experiment (60 weeks of age). Results: Castration attenuated proteinuria and glomerular sclerosis accompanied by an amelioration of glucose tolerance, a decrease in mesangial expansion and an attenuation of the GBM thickening. In contrast, although estrogen equally ameliorated glucose tolerance and attenuated the mesangial expansion and the GBM thickening, estrogen failed to attenuate proteinuria and glomerulosclerosis. A significant increase in glomerular tuft volume, and serum levels of growth hormone, total cholesterol and triglycerides was observed in the estrogen-treated rats as compared with the castrated rats. Conclusion: Besides the mechanisms involved in the development of diabetic nephropathy, other mechanisms may be involved and contribute to the development of glomerulosclerosis in the estrogen-treated rats, leading to a difference in glomerular injury between the castrated and estrogen-treated OLETF rats.

Roxithromycin and clarithromycin, 14-membered ring macrolides, potentiate the antitumor activity of cytotoxic agents against mouse B16 melanoma cells.

We previously reported antiangiogenic activity of roxithromycin and clarithromycin, 14-membered ring macrolide antibiotics. In the present study, we examined the antitumor effects of roxithromycin and clarithromycin, alone and in combination with several cytotoxic drugs, on mouse B16BL6 melanoma cells in vivo and in vitro. Both roxithromycin and clarithromycin potentiated the inhibition of tumor growth induced by cyclophosphamide, cis-diamminedichloroplatinum(II), Adriamycin and vindesine in vivo. However, neither roxithromycin nor clarithromycin, altered the cytotoxicity of 4-hydroperoxycyclophosphamide, cis-diamminedichloroplatinum(II), Adriamycin or vindesine in an in vitro cell proliferation assay. These results suggest that the antiangiogenic activity of roxithromycin and clarithromycin may provide beneficial effects in combination with cytotoxic therapies against solid tumors.

Nephrotic Syndrome due to Immunologically Mediated Hypocomplementic Glomerulonephritis in a Patient of Waldenström’s Macroglobulinemia

A 72-year-old man was diagnosed as having nephritic syndrome complicated by Waldenström’s macroglobulinemia (WM). A monoclonal IgM lamda protein and decreased serum complements were observed. The renal biopsy disclosed the capillary occluded by thrombi which was stained with IgG, IgA, IgM, C4, lamda light chain and slight kappa light chain in a granular pattern. Electron dense deposits were noted in the subendothelial spaces. An unusual case of WM who developed nephrotic syndrome due to immunologically mediated hypocomplementic glomerulonephritis is described.