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Biomedical subjects

Eisuke Tsuda

Publications and source records attributed to Eisuke Tsuda.

5 recordsLinked to original sources
PubMed2002

Transgenic mice overexpressing soluble osteoclast differentiation factor (sODF) exhibit severe osteoporosis.

Osteoclast differentiation factor, ODF, also called RANKL, TRANCE, or OPGL, is a key molecule for osteoclast differentiation and activation, and is thought to act as a membrane-associated molecule in bone remodeling. Recent study suggested that soluble ODF (sODF) released from T cells also has some roles in bone resorption. To investigate the physiological and pathological function of sODF, we generated two types of transgenic mice overexpressing sODF. Mice overexpressing sODF ubiquitously from the early developmental stage died at the late fetal stage. The other type of mice, expressing sODF only in the liver after birth, grew to maturity with normal body size and weight. However, they exhibited a marked decrease in bone mineral density with aging compared with their non-transgenic littermates, and in addition, the strength of their femurs was extremely reduced. Histological analysis showed that the trabecular bone mass was decreased at 6 weeks of age and was sparse at age 3-4 months. The number of osteoclasts was significantly increased, while the number of osteoblasts was not altered on the surface of young trabecular bone. These results indicate that excessive production of sODF causes osteoporosis by accelerated osteoclastogenesis. The transgenic mouse overexpressing sODF in the liver could serve as a useful animal model for studying bone remodeling and evaluating therapeutic agents for osteoporosis.

Acute Disease↗
PubMed2002

Osteoclastogenesis inhibitory factor/osteoprotegerin ameliorates the decrease in both bone mineral density and bone strength in immobilized rats.

Rat models of immobilization-induced osteopenia are characterized by uncoupling of bone metabolism, i.e., increased bone resorption and decreased bone formation in trabecular bone. Using such a rat model, the efficacy of osteoclastogenesis inhibitory factor (OCIF)/osteoprotegerin, a novel secreted protein that inhibits osteoclastogenesis, in reducing bone loss was investigated. Male Fischer rats were neurectomized and injected intramuscularly with either OCIF (0.2, 1.0, or 5.0 mg/kg body weight) or vehicle once daily for 7 days. On the eighth day after sciatic neurectomy, significant bone loss was observed in the vehicle-injected rats. OCIF ameliorated the decrease in bone mineral density (BMD) of both the proximal and distal femur in a dose-dependent manner. OCIF also ameliorated the decrease in bone strength of the femoral neck at the highest dose. A high correlation (r = 0.805) was detected between the BMD of the distal femur and the bone strength of the femoral neck. When OCIF was administered intermittently to the immobilized rats twice weekly (on days 1 and 4) after immobilization, it also ameliorated the decrease in BMD of the distal femur. These results suggest that OCIF has therapeutic potential for the treatment of immobilization-induced osteopenia.

Animals↗
PubMed2002

Increased circulating levels of osteoclastogenesis inhibitory factor (osteoprotegerin) in patients with chronic renal failure.

Skeletal resistance to parathyroid hormone (PTH) is one of the major abnormalities underlying bone diseases in uremia, the mechanism of which has not yet been fully elucidated. Osteoclastogenesis inhibitory factor (OCIF), or osteoprotegerin, is a natural decoy receptor for osteoclast differentiation factor (ODF), produced by osteoblasts in response to PTH. To elucidate the kinetics and roles of OCIF in chronic renal failure, serum OCIF levels were measured in 46 predialysis patients and 21 dialysis patients by means of enzyme-linked immunosorbent assay (ELISA). Serum OCIF levels in predialysis patients increased as renal function declined (OCIF = 1.178 + 0.233 x creatinine; r2 = 0.413; P < 0.0001). Twenty-four-hour creatinine clearance and 1/OCIF in predialysis patients showed a clear positive correlation and a straight line regression (1/OCIF = 0.443 + 0.004 x creatinine clearance; r2 = 0.425; P < 0.0001). In dialysis patients, serum OCIF levels were significantly elevated (5.18 +/- 1.48 ng/mL) to a level that would inhibit 50% osteoclast formation in vitro. These findings suggest that OCIF accumulates in serum of patients with renal dysfunction. Because serum levels of OCIF with the ability to bind ODF in vitro (active OCIF) correlated well with those of OCIF detected by standard ELISA (active OCIF = 0.251 + 0.877 x OCIF; r2 = 0.829; P < 0.0001), OCIF accumulated in serum may be a candidate uremic toxin responsible for the skeletal resistance to PTH seen in chronic renal failure. Further studies with serum parameters and bone histological evaluation are needed to assess this possibility.

Aged↗
PubMed2002

SNF4435C and D, novel immunosuppressants produced by a strain of Streptomyces spectabilis. III. Immunosuppressive efficacy.

Novel immunosuppressants, SNF4435C and D produced by a strain of Streptomyces spectabilis, were examined for their pharmacodynamical profiles. SNF4435C and D suppressed the responses of both murine splenocytes and human peripheral blood lymphocytes in the mixed lymphocyte reaction (MLR) with IC50 values of 0.5 microM and 0.2 microM, respectively. In the mouse MLR experiments, SNF4435C and D did not block the production of interleukin-2 (IL-2) and the compounds-induced suppression was not restored by the addition of exogeneous IL-2. In addition, the significant inhibitory action was still retained even when SNF4435C or D was added after 48 hours from the start of the culture. These results were distinct from the behaviors observed with FK-506. SNF4435C, the major component, suppressed mouse delayed type hypersensitivity (DTH) and prolonged rat skin allograft survival.

Animals↗