伊藤 光泰

Post-transplantation bone diseases negatively affect the quality of life of solid organ recipients. Secondary or tertiary hyperparathyroidism is a frequent complication in kidney transplantation (KTx) recipients. Treatment with immunosuppressive agents including glucocorticoids can lead to deterioration in bone metabolism in these patients. In the present study, we explored the effects of a three-year treatment period with oral alendronate (ALN) in long-term KTx recipients. Post-KTx recipients were recruited (n = 24, M/F = 12/12, mean age 52.0 +/- A 7.8 years) into this study. All patients were prescribed methylprednisolone (4.07 +/- A 0.86 mg/day) with various immunosuppressive agents. Before treatment with oral ALN (35 mg/week), the mean concentrations of intact parathyroid hormone (iPTH) and 25-hydroxyvitamin D were 139.2 +/- A 71.4 pg/mL and 20.8 +/- A 4.1 ng/mL, respectively. After 36 months of ALN treatment, mean iPTH levels increased slightly (+20.9 %). Treatment with ALN reduced bone-specific alkaline phosphatase (-35.4 %), serum type I collagen N-terminal telopeptide (-31.2 %) and osteocalcin (-55.6 %) levels. ALN did not increase bone mass after 24 months. Four patients with the highest baseline iPTH levels suffered a clinical osteoporotic fracture during the 36-month ALN treatment period. Higher iPTH levels with chronic kidney disease (CKD) at baseline were associated with the incidence of new clinical fractures during ALN treatment. In conclusion, anti-resorptive therapy with ALN can suppress bone turnover even when iPTH concentration is elevated in long-term KTx recipients. However, hyperparathyroidism with CKD seems to be associated with new clinical fractures during ALN treatment.

Aripiprazole is the only atypical antipsychotic drug known to cause the phosphorylation of AMP-activated protein kinase (AMPK) in PC12 cells. However, the molecular mechanisms underlying this phosphorylation in aripiprazole-treated PC12 cells have not yet been clarified. Here, using PC12 cells, we show that these cells incubated for 24 h with aripiprazole at 50 mu M and 25 mM glucose underwent a decrease in their NAD(+)/NADH ratio. Aripiprazole suppressed cytochrome c oxidase (COX) activity but enhanced the activities of pyruvate dehydrogenase (PDH), citrate synthase and Complex I. The changes in enzyme activities coincided well with those in NADH, NAD(+), and NAD(+)/NADH ratio. However, the bioenergetic peril judged by the lowered COX activity might not be accompanied by excessive occurrence of apoptotic cell death in aripiprazole-treated cells, because the mitochondrial membrane potential was not decreased, but rather increased. On the other hand, when PC12 cells were incubated for 24 h with clozapine at 50 mu M and 25 mM glucose, the NAD(+)/NADH ratio did not change. Also, the COX activity was decreased; and the PDH activity was enhanced. These results suggest that aripiprazole-treated PC12 cells responded to the bioenergetic peril more effectively than the clozapine-treated ones to return the ATP biosynthesis back toward its ordinary level. This finding might be related to the fact that aripiprazole alone causes phosphorylation of AMPK in PC12 cells.

Adenomatous polyposis coli (Apc) is a multifunctional protein as well as a tumor suppressor. To determine the functions of the C-terminal domain of Apc, we examined Apc (1638T/1638T) mice that express a truncated Apc lacking the C-terminal domain. The Apc (1638T/1638T) mice were tumor free and exhibited growth retardation. We recently reported abnormalities in thyroid morphology and functions of Apc (1638T/1638T) mice, although the mechanisms underlying these abnormalities are not known. In the present study, we further compared thyroid gland morphology in Apc (1638T/1638T) and Apc (+/+) mice. The diameters of thyroid follicles in the left and right lobes of the same thyroid gland of Apc (1638T/1638T) mice were significantly different whereas the Apc (+/+) mice showed no significant differences in thyroid follicle diameter between these lobes. To assess the secretory activities of thyroid follicular cells, we performed double-immunostaining of thyroglobulin, a major secretory protein of these cells, and the rough endoplasmic reticulum (rER) marker calreticulin. In the Apc (1638T/1638T) follicular epithelial cells, thyroglobulin was mostly colocalized with calreticulin whereas in the Apc (+/+) follicular epithelial cells, a significant amount of the cytoplasmic thyroglobulin did not colocalize with calreticulin. In addition, in thyroid-stimulating hormone (TSH)-treated Apc (1638T/1638T) mice, electron microscopic analysis indicated less frequent pseudopod formation at the apical surface of the thyroid follicular cells than in Apc (+/+) mice, indicating that reuptake of colloid droplets containing iodized thyroglobulin is less active. These results imply defects in intracellular thyroglobulin transport and in pseudopod formation in the follicular epithelial cells of Apc (1638T/1638T) mice and suggest suppressed secretory activities of these cells.

Background: Interactions between CD40 and its ligand (CD40L) have important roles in T-cell-dependent activation of B cells, which may be related to the thyrotoxic activity of Graves' disease (GD). Soluble forms of CD40 ligand (sCD40L) are released from activated T cells and platelets, and several types of inflammatory cytokines are increased in patients with hyperthyroid GD. The aim of this study was to assess sCD40L and other cytokines as clinical indicators of disease activity or as possible markers of remission in GD. Methods: Serum levels of sCD40L, interleukin 18 (IL-18), tumor necrosis factor-alpha (TNF alpha), and TNF alpha receptors 1 and 2 (TNFR1 and TNFR2) were investigated in patients with active GD (GD-A), intractable GD (GD-IT), inactive GD (GD-IA), GD in remission (GD-R), and Hashimoto's thyroiditis (HT), and in control subjects (CON). Results: Serum concentrations of sCD40L were higher in the GD-A and GD-IT groups than in the HT and CON groups. Similarly, serum concentrations of IL-18, which induces Th1 cytokines, such as interferon-gamma, were higher in the GD-A and GD-IT groups than in all other groups. Serum levels of TNFR1 and TNFR2 were also significantly higher in the GD-A than in all other groups. The mean serum concentration of TNF alpha was higher in the GD-R compared with the GD-A and GD-IT groups, although the difference was not significant. Serum sCD40L concentrations in the GD-R group were lower than in the GD-A and GD-IT groups. Finally, the ratio of serum TNF alpha to sCD40L was higher in the GD-R group than in the GD-A and GD-IT groups. This is the first report that serum sCD40L is increased in active GD, and that the serum TNF alpha:sCD40L ratio is a marker for remission in GD. Conclusions: Our results suggest that not only thyrotoxicosis, but also the activity of the immunoreaction presenting as anti-thyrotropin receptor antibodies (TRAb) titer in GD, affects inflammatory cytokine serum profiles. Serum profiles of cytokines vary in patients with GD depending on disease activity. An elevated serum TNF alpha:sCD40L ratio indicates declining disease activity and reflects a shift from Th2 to Th1 dominance, suggesting that suppression of sCD40L or increased production of TNF alpha is required to initiate or maintain remission of GD.

Background: Chronic elevation of cardiac troponin T (TnT) levels as measured by conventional assays is strongly associated with structural heart disease and cardiovascular events. A new high-sensitivity assay for TnT makes it possible to measure concentrations more than a factor of 5 lower than the limits of detection of conventional assays. We evaluated the utility of serum TnT as a risk marker of cardiovascular disease in 409 outpatients with type-2 diabetes mellitus (T2DM). Results: TnT was detectable (&gt 0. 002 ng/mL) in 80% of patients, and elevation in TnT levels (&gt 0. 014 ng/mL) was found in 19. 3%, suggesting a higher prevalence of structural heart diseases in T2DM patients. A history of cardiovascular disease was noted in 89 (22%) patients. Patients with diabetic microvascular complications and those with abnormal electrocardiogram including left ventricular hypertrophy had higher TnT levels. Patients with increased levels of TnT (&gt 0. 014 ng/mL) were older, had higher values of N-terminal pro-B-type natriuretic peptide (NT-proBNP), C-reactive protein, cystatin C, and urinary albumin/creatinine ratio, had lower values of hemoglobin and estimated glomerular filtration rate, and had a higher prevalence of cardiovascular disease compared with those without increased TnT levels. In stepwise logistic analysis, NT-proBNP (odds ratio 7. 40 per 10-fold increase, P &lt 0. 0001) and cystatin C (18. 0 per 1. 0 mg/L, P &lt 0. 0001) were independently associated with elevation of TnT levels. HsTnT level, cystatin C, and HDL-cholesterol were also independent risk factors for history of major cardiovascular diseases in T2DM patients. Conclusion: This new high-sensitivity TnT assay may be useful for stratifying cardiovascular risk in outpatients with T2DM. © 2011 The Japan Diabetes Society.