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Osteopontin (OPN) is an important matrix protein of renal calcium stone. However, the function of OPN in the early phase of renal crystal formation is not well defined. In this study, we examined OPN expression in the early phase of renal crystal formation with ultra-microstructural observations and immuno-TEM (transmission electron microscopy) in control and OPN knock-out (OPN-KO) mice. Glyoxylate (100 mg/kg) was intra-abdominally administered to male wild-type mice (C57BL/6, 8 weeks of age) and OPN-KO mice (C57BL/6, 8 weeks of age). Kidney was collected before and 6, 12, and 24 h after administration. We examined the relation between renal crystal formation and microstructural OPN location using TEM and immunohistochemical staining of OPN as well as western blotting and quantitative RT-PCR for OPN. OPN protein expression gradually increased in the renal cortex-medulla junction after glyoxylate administration, and OPN mRNA was increased until 12 h, but decreased at 24 h. In ultra-microstructural observation, OPN began to appear on the luminal side of renal distal tubular cells at 6 h and was gradually detected in the tubular lumen at 12 h. OPN was present in the crystal nuclei and collapsed mitochondria in the tubular lumen. In the OPN-KO mice, collapsed mitochondria were present, but no crystal nuclei formation were detected at 24 h. Based on the results this study proposed that the appearance of organelles, such as mitochondria and microvilli, in the tubular lumen after cell injury may be the starting point of crystal nucleus formation due to the aggregation ability of OPN.

Renal stone formation and renal failure among Chinese infants administered melamine-containing formula were increasingly reported in 2008. We investigated the mechanism by which melamine and cyanuric acid induce renal stone formation and renal failure. Ten-week-old rats were administered either melamine [2.4, 24, or 240 mg/kg/day], both melamine and cyanuric acid [each at 1.2, 12, or 120 mg/kg/day], or water (controls). Blood and 24-h urine samples and kidney sections were evaluated on days 3, 7, and 14. In rats administered melamine alone or the low-dose melamine/cyanuric acid combination [1.2 mg/kg/day], crystals were not detected. On day 3, crystal formation was observed in the renal distal tubular lumens and collecting ducts of rats administered the intermediate-dose melamine/cyanuric acid [12 mg/kg/day], and the number of crystals increased during the course of the experiment. In rats administered the high-dose melamine/cyanuric acid [120 mg/kg/day], crystals were found in the proximal tubular lumens of the renal cortex on day 3, but acute renal failure resulted in death by day 7. Polarized light optical microphotography and scanning electron microscopy revealed tubular lumens occluded by a layer of axle-shaped crystals. X-ray diffraction findings revealed a nitrogen component but no calcium. The upper regions of occluded tubes were expanded, and the epithelium was thin. Melamine and cyanuric acid in combination, but not by melamine alone induce crystal formation and affected renal functioning. Renal failure due to melamine cyanurate crystals appears to occur via tubular occlusion.

Crystal formation in mice could not be induced either by the administration of ethylene glycol or by glycolate. To clarify the reasons for the difference among these oxalate precursors in mice, we studied renal tubular epithelial injury by immunohistochemical staining of oxidative stress and observing microstructures. Daily intra-abdominal injection of saline solution [10 ml/(kg day)], ethylene glycol[(48.3 mmol/(kg day)], glycolate [1.31 mmol/(kg day)], and glyoxylate [1.35 mmol/(kg day)] into C57BL/6 male mice (8 weeks) was performed for 7 days. Immunohistochemical staining of superoxide dismutase (SOD) and malondialdehyde (MDA), and transmission electron microscopy (TEM) of renal tubular epithelial cells were performed to observe oxidative stress and morphological changes, respectively. Decreased SOD and increased MDA were shown only in glyoxylate-treated mouse kidneys. The TEM study with glyoxylate-treated mouse kidneys demonstrated that the internal structure of mitochondria in renal tubular cells underwent destruction and vacuolization, and microvilli density decreased. These changes in renal tubular cells were located in the crystal-forming area. However, such changes were not detected in the other groups. Each precursor of oxalate induces different changes in renal epithelial cells regarding oxidative stress and the microstructural changes. It is suggested that calcium oxalate crystal formation requires cell injury and morphological changes of renal epithelial tubular cells induced by glyoxylate administration in the mouse kidney.

The establishment of an experimental animal model would be useful to study the mechanism of kidney stone formation. A calcium kidney stone model in rats induced by ethylene glycol has been used for research; however, to investigate the genetic basis affecting kidney stone formation, which will contribute to preventive medicine, the establishment of a kidney stone model in mice is essential. This study indicates the optimum conditions for inducing calcium oxalate stones in normal mouse kidney. Various doses of oxalate precursors, ethylene glycol, glycolate and glyoxylate, were administered either by free drinking or intraabdominal injection for 2 months as a preliminary study. Stone formation was detected with light microscopy, polarized light optical microscopy and electron microscopy. Stone components were detected with X-ray diffraction analysis. The expression of osteopontin (OPN), a major stone-related protein, was detected with immunohistochemical staining, in situ hybridization and quantitative reverse transcriptase polymerase chain reaction. Kidney stones were not detected in ethylene glycol- or glycolate-treated groups even at the highest dose of LD(50). Whereas, numerous kidney stones were detected in glyoxylate-treated mice (more than 60 mg/kg) at 3, 6 and 9 days after glyoxylate were administered intraabdominally. However, the number of kidney stones decreased gradually at day 12, and was hardly detected at day 15. The stone component was further analyzed as calcium oxalate monohydrate. A dramatic increase in the expression of OPN was observed by the administration of glyoxylate. We established a mouse kidney stone experimental system in this study. The difficulty of inducing kidney stones suggested that mice have greater intrinsic ability to prevent stone formation with hyperoxaluric stress than rats. The differing response to hyperoxaluric stress between mice and rats possibly contributes to the molecular mechanism of kidney stone formation and will aid preventive medicine in the future.

The incidence of urolithiasis has increased in the industrialized nations. However, both the pathogenesis and methods for its prevention remain to be clarified. We demonstrate that the antioxidative effect of green tea decreases the formation of calcium oxalate stones, OPN (osteopontin) expression, and apoptosis, and increases SOD (superoxide dismutase) activity in rat kidney tissues. The inhibitory effect of green tea on calcium oxalate urolithiasis is most likely due to its antioxidative effects. Therefore, we examined oxidative stress in vivo applied to Madin-Darby canine kidney (MDCK) cells, to which catechin, an antioxidant, was added. To evaluate the effects of oxidative stress on MDCK cells, we use a hypoxic condition because hypoxia is known to lead to oxidative stress. Confluent cultures of MDCK cells were exposed to (-)epigallocatechin 3 gallate (EGCG) (0, 0.1, 0.5, 5.0 mg/ml) for 2, 4, 8 or 16 h to determine changes in protein secretion and apoptosis. OPN protein expression was observed in MDCK cells of all 16 groups. The levels of expression of OPN protein were the same among all groups. In all groups, SOD protein expression was observed. In the groups exposed to EGCG 0.5, 5.0 mg/ml, SOD staining was more enhanced than in the EGCG 0 and 0.1 mg/ml groups. No deposits were detected in any of the 16 groups. RT-PCR was performed to detect sequences from OPN (979 bp) and SOD (447 bp). Quantitative analyses showed that SOD activity decreased gradually in all groups. Only in the EGCG 0 mg/ml 16 h group were TUNEL-positive cells observed. In the other groups, TUNEL-positive cells were not detected. EGCG used as an antioxidant protects renal tubular cell from cellular injury caused by oxidative stress through SOD protein expression.

Osteoporosis is associated with the pathogenesis of urinary stone formation. Urinary stones are similar to bone diseases such as osteoporosis and bone metabolism in terms of pathogenesis. Bisphosphonates are potent inhibitors of bone resorption, and are used in the management of bone disease. Furthermore, bisphosphonates have a strong affinity for calcium, and a reported inhibitory effect on calcium oxalate crystallization in vitro. Thus, bisphosphonates might also inhibit urinary stone formation. Madin-Darby canine kidney (MDCK) cells form calcium phosphate microliths at the basolateral side in vitro. We investigated the inhibitory effects of new generation bisphosphonates (alendronate and incadronate) on calcium phosphate microlith formation and on the expression of osteopontin, which is an important urinary stone matrix. MDCK cells formed two types of colonies in three-dimensional soft agar culture; dark colonies containing calcium phosphate microliths and clear colonies free from microliths. We applied purified alendronate and incadronate at concentrations of 10(-11), 10(-9), 10(-7) and 10(-5) M to MDCK cells cultured in three-dimensional soft agar and investigated the efficiency of colony formation and the dark colony ratio (number of dark colonies relative to the total number of colonies). The administration of 10(-9) and 10(-7) M alendronate decreased the dark colony ratio compared with controls, whereas incadronate did not significantly alter this colony ratio compared with controls. The expression of osteopontin in cultured cells was inhibited by the 10(-7) M alendronate administration. The present findings show that alendronate inhibits calcium stone formation, suggesting that it is effective in the prevention of urolithiasis.

Transcription factor nuclear factor kappaB (NF-kappaB) controls gene expression of a number of genes, including cytokines such as interleukin-6 (IL-6), granulocyte-macrophage (GM)-CSF, and interleukin-8 (IL-8). IL-6 is known to play important roles in the growth of prostate cancer cells, activation of androgen receptor, and prostate-specific protein expression. NF-kappaB is activated by extracellular signals such as proinflammatory cytokines, chemotherapeutic reagents, and radiation. Here we demonstrate that cisplatin (CDDP) and etoposide (VP-16) induce nuclear translocation of NF-kappaB in prostate cancer cell lines, followed by secretion of IL-6. We also demonstrated that the growth of hormone-independent prostate cancer cell lines can be inhibited by the anti-NF-kappaB reagent N-acetyl-L-cysteine (NAC). These observations indicate that NF-kappaB can be a target of new adjuvant therapy against hormone refractory prostate cancer.

Previous studies have described the inhibitory effects of citrate on calcium oxalate crystallization in place of crystal growth, but the effects of citrate on matrix proteins of stones has not been studied in vivo. To examine the effect of citrate on the matrix, we investigated the effect of citrate on osteopontin (OPN) expression, which we had previously identified as an important stone matrix protein. Control rats were treated with saline while rats of the stone group were treated with ethylene glycol (EG) and vitamin D3, and the citrate groups (low-dose and high-dose groups) were treated with a citrate reagent compound of sodium citrate and potassium citrate, in addition to EG and vitamin D3. The rate of renal stone formation was lower in the citrate groups than in the stone group. This was associated with a low expression of OPN mRNA in citrate-treated rats relative to that in the stone group. Citrate was effective in preventing calcium oxalate stone formation and reduced OPN expression in rats. Our results suggest that citrate prevents renal stone formation by acting against not only the crystal aggregation and growth of calcium oxalate but also OPN expression.

Although a bladder cancer-specific abnormality in chromosomes or genes has not been reported, chromosomal regions that tend to become abnormal have been recognized. In this study, we investigated abnormalities in chromosomes 8 and 11. There were 27 patients with bladder cancer, 16 males and 11 females, who participated in this study. Abnormalities in chromosomes 8 and 11 were investigated by the fluorescence in situ hybridization (FISH) method. Probes used in this study were chromosome 8 alpha-satellite and chromosome 11 alpha-satellite (Oncor Co.). Of 27 cases, 15 cases were positive for chromosome 8 (55.6%) and ten cases were positive for chromosome 11 (37.0%). Since the FISH method detects chromosomal abnormality by the number of signals generated in cancer cells, this method is objective and simple and thus may be applicable in clinical practice.

Bacillus Calmette-Guerin (BCG) immunotherapy for superficial bladder cancer is now widespread, but non-effective cases are not uncommon and it has yet to be clarified why this is the case. In an attempt to cast light on this problem, we evaluated differences between effective and non-effective cases immunohistochemically using p53, proliferating cell nuclear antigen (PCNA), and bcl-2 antibodies. Between March 1988 and March 1996 a total of 79 superficial bladder cancer patients were treated with BCG intravesical instillation therapy after transurethral resection of bladder tumor (TUR-Bt). Of these, 19 demonstrated recurrence after the initial treatment. From the 60 remaining patients without recurrence, we randomly chose 19 additional cases and evaluated both series for p53, PCNA and bcl-2 immunohistochemical staining using formalin-fixed, paraffin-embedded tissues. For the recurrent cases, material taken prior and subsequent to BCG therapy was available for 17 of the 19 patients. Positive staining for p53 was noted for 42.1% (8/19) of both recurrent and non-recurrent cases, without any difference between the two. The rates for PCNA and bcl-2 were 52.6% (10/19) and 47.4% (9/19) in recurrent, and 36.8% (7/19) and 78.9% (15/19) in non-recurrent cases, respectively. Thus, there was a significant difference for lower incidences of bcl-2 in recurrent cases (P = 0.044). Values for p53 and bcl-2 were respectively 47.1% (8/17) and 41.2% (7/17) pre-treatment, and 52.9% (9/17) and 35.3% (6/17) post-treatment in the recurrence group. In contrast to the similarity in these results, PCNA positive cases were 52.9% (9/17) pre-treatment and 17.6% (3/17) post-treatment. These data suggest that there are differences between BCG-sensitive and BCG-resistant bladder cancers in terms of bcl-2 expression.

We studied the metabolism of testosterone in primary cultures of prostate epithelial cells and fibroblasts obtained from patients with benign prostatic hyperplasia (BPH). The conversion of 3H-testosterone in both cell cultures was predominantly to the oxidative pathway, with the formation of 3H-androstenedione increasing with cell number and time of incubation. Although we also detected some 5 alpha-reductase activity in these cells, the activity in the stroma component (0.00688 pmol/mg protein/min) was nonetheless insignificant when compared to the 5 alpha-reductase activity in the tissue of origin (0.0616 pmol/mg protein/min) and well below the 17 beta-hydroxysteroid dehydrogenase activity of the same cells (0.0518 pmol/mg protein/min). The aromatase activity in our cells was also measured by two separate techniques, but neither the deuterium procedure nor the production of oestrone from androgen precursors yielded any positive results, suggesting that under these experimental conditions there was no aromatase activity within the cells. The shift from the reductive to the oxidative pathways in these primary cell cultures was reminiscent of the androgen-metabolizing enzyme profiles seen in poorly differentiated prostate cancer. Whether this transition is an obligatory step in the development of hormone refractiveness remains to be elucidated.