Search

OBJECTIVE To investigate the association between metabolic syndrome and urinary stone disease, and whether insulin resistance associated with adiposity affects the risk of urinary stone formation, using a rat model of metabolic syndrome. MATERIALS AND METHODS Four-week-old male Otsuka Long-Evans Tokushima 'Fatty' (OLETF, a model of human type 2 diabetes and metabolic syndrome) rats, and Long-Evans Tokushima (LETO, a non-diabetic control) rats (10 each) were given a standardized diet and free access to water. Body weight and serum and urinary biochemistry were determined every 4 weeks. Ten-week-old male OLETF and LETO rats were divided into three groups of nine each and treated with vehicle or oral administration of 3 or 10 mg/kg/day pioglitazone, an agent that improves insulin resistance. After 4 weeks, body weight and serum and urinary biochemistry were determined. RESULTS The OLETF rats had significantly lower urinary pH and citrate excretion, and higher urinary uric acid and calcium excretion, than the LETO rats, with increases in body weight, serum triglyceride, glucose and insulin. The administration of pioglitazone to the OLETF rats for 4 weeks significantly increased urinary pH dose-dependently. There was no change in the urinary excretion of citrate, uric acid, calcium, oxalate or magnesium. CONCLUSION These results indicate that metabolic syndrome causes the changes in urinary constituents, leading to increased risk of both uric acid and calcium stone formation. Improvement in insulin resistance, a central cause of metabolic syndrome, might prevent uric acid stone formation by raising urinary pH.

OBJECTIVE To determine whether dendritic cells (DC) transduced with the prostate-specific antigen (PSA) gene can induce PSA-specific cytotoxic lymphocytes (CTL) against prostate cancer cells, and whether bacillus Calmette-Guerin (BCG) cell-wall skeleton (CWS) can enhance the maturation of DC-PSA and the killing activity of subsequently induced PSA-specific CTL. MATERIALS AND METHODS We generated an adenovirus encoding the PSA gene (AxCA-PSA) using the cosmid-terminal protein complex method. DC were infected with AxCA-PSA using the centrifugal method. The ability of CTL to lyse target cells expressing PSA, i.e the PSA-positive prostate cancer cell line, LNCap, and PSA-transduced autologous phytohaemagglutinin (PHA) blasts expressing PSA, was assessed using the 51Cr-release assay. The maturation of DC-PSA stimulated by BCG-CWS was assayed by flow cytometry. The cytotoxic activity enhanced by BCG-CWS was assessed by the 51Cr-release assay. RESULTS DC-PSA induced PSA-specific CTL with 85% cytotoxic activity against LNCaP (effector: target ratio, E:T, of 50:1). However, the cytotoxic activity against PSA-negative cells was very low. Anti-CD8 and anti-major histocompatibility (MHC) class I antibodies blocked PSA-specific cytotoxicity. The PSA-specific killing was reproducible against autologous PHA blast cells expressing PSA, independently of human leukocyte antigen haplotype. Furthermore, the combination of DC-PSA with BCG-CWS remarkably enhanced the PSA-specific cytotoxicity against PHA blasts expressing PSA (15–30% at an E:T ratio of 50:1). CONCLUSION These findings suggest that DC-PSA can induce MHC class I-restricted PSA-specific CD8+ CTL responses and that DC-PSA matured by BCG-CWS enhance PSA-specific cytotoxicity. The combination of DC-PSA with BCG-CWS might be a useful approach for treating advanced prostate cancer.

OBJECTIVES • To evaluate the antitumour effects of IL-23 gene transfer into mouse bladder carcinoma (MBT2) cells. • To investigate the mechanisms underlying the subsequent constitutive secrection of IL-23 by the MBT2 cells MATERIALS AND METHODS • An expression vector containing IL-23 gene was introduced into MBT2 cells by liposome-mediated gene transfer, and secretion of IL-23 was confirmed by ELISA. • The in vivo antitumour effect of IL-23-secreting MBT2 cells (MBT2/IL-23) was examined by injecting the cells into syngeneic C3H mice. • A tumour vaccination study using mitomycin C (MMC)-treated IL-23-secreting MBT2 cells was carried out, and the usefulness of in vivo CD25 depletion for an additional vaccine effect was also investigated. • The mechanisms underlying the antitumour effects were investigated by antibody depletion of CD8 or CD4 T cells, or natural killer cells, and cells infiltrating the tumour sites in vivo were assessed using immunohistochemistry. RESULTS • Stable transformants transduced with MBT2/IL-23 secreted IL-23 into the culture supernatant. • Genetically engineered IL-23-secreting MBT2 cells were rejected in syngeneic mice. • MBT2/IL-23-vaccinated mice inhibited the tumour growth of parental MBT2 cells injected at a distant site and this vaccine effect was enhanced by combination with in vivo CD25 depletion by an antibody. • The main effector cells for the direct antitumour effect of MBT2/IL-23 were CD8 T cells, which was shown by in vivo depletion and immunohistochemical study. CONCLUSIONS • IL-23-secreting MBT2 cells were rejected in syngeneic mice by the activation of CD8 T cells. • MMC-treated MBT2/IL-23 can have a tumour vaccine effect for parental MBT2 cells, and this effect was enhanced by combination with in vivo CD25 depletion.