Feasibility of metronomic chemotherapy with tegafur-uracil, cisplatin, and dexamethasone for docetaxel-refractory prostate cancer.

Objectives: To evaluate the efficacy of tegafur-uracil (UFT), a prodrug of 5-fluorouracil, plus cisplatin and dexamethasone in patients with docetaxel-refractory prostate cancers. Methods: Twenty-five patients with docetaxel-refractory prostate cancer were administered oral UFT plus intravenous cisplatin (UFT-P therapy) and dexamethasone. Treatment responses were assessed monthly via prostate-specific antigen (PSA) level measurements. Treatment-related adverse events and overall survival were also assessed. Results: UFT-P therapy resulted in decreased PSA levels in 14 (56%) patients and increased PSA levels in 11 (44%). In patients with increased PSA levels, 7 (64%) of the 11 patients displayed decreased PSA doubling times. The UFT-P therapy response rate was 84% (21/25 patients). Imaging studies revealed that tumor shrinkage during UFT-P therapy occurred in 1 patient in whom bilateral hydronephrosis caused by lymph node metastasis improved. The median survival time from docetaxel initiation was 36 months. In UFT-P-treated patients, the median PSA progression and overall survival times were 6 and 14 months, respectively. UFT-P treatment-related adverse events were mild diarrhea, general fatigue, and anorexia. Treatment was not discontinued for any of the patients. UFT-P therapy did not cause serious hepatic or renal dysfunction or pancytopenia. Conclusions: UFT-P therapy is a safe and effective treatment for patients with docetaxel-refractory prostate cancer, although large-scale, multicenter, prospective studies are needed to validate these findings.

Clear cell sarcoma of the kidney distinguished from synovial sarcoma using genetic analysis: a case report.

BACKGROUND: The most common pediatric renal neoplasm is Wilms tumor, but clear cell sarcoma of the kidney or synovial sarcoma of the kidney are also sometimes encountered. Accurate pathological diagnosis is important, because adjuvant therapies including chemotherapy and radiotherapy differ according to the pathological type. CASE PRESENTATION: A 9-year-old boy presented with a headache, and ultrasonography, computed tomography, and magnetic resonance imaging revealed a heterogeneous enhancement of soft tissue originating from the upper pole of the left kidney, measuring approximately 11.0 × 10.0 × 8.0 cm. A left radical nephrectomy was performed using an intraperitoneal approach through an anterior subcostal incision. Pathological examination suggested clear cell sarcoma of the kidney or synovial sarcoma of the kidney based on morphological and immunohistological features. Using genetic analysis, a final diagnosis of spindle cell pattern clear cell sarcoma of the kidney was made based on the absence of the SYT-SSX fusion gene. After adjuvant chemo-radiotherapy was administered, no recurrence or metastasis has been identified as of 60 months postoperatively. CONCLUSION: In this case, it was difficult to discriminate clear cell sarcoma of the kidney from synovial sarcoma of the kidney based on histopathological examination alone, and genetic analysis was required. Accurate pathological diagnosis of pediatric renal tumor is important for determining optimal treatment and preventing recurrence and metastasis.

Long-term follow-up of nephrotoxicity in rats administered both melamine and cyanuric acid.

BACKGROUND: Melamine was recently identified as a risk factor for renal calculi following the milk powder contamination in China. However, the long-term natural history of melamine exposure and its renal effects remain unknown. We evaluated renal function and other adverse health effects using a rat model administered melamine and cyanuric aid, considering age and sex. METHODS: Twelve male F334/N rats each of ages 6, 10, and 26 weeks (N = 36) were equally assigned to Group M + C or controls. Group M + C rats were administered 12 mg · kg(-1) · day(-1) of melamine and cyanuric acid for 28 days. Serum and urine samples and kidney sections were evaluated on day 28. Six-week-old male and female F344/N rats were administered 12 mg of melamine and cyanuric acid for 28 days. Body weights were measured weekly; on days 0, 28, 90, and 180 after the 28-day period of melamine and cyanuric acid administration, serum samples and kidney sections were obtained. RESULTS: Although the control group had no crystals, 6-week-old Group M + C rats had more crystals compared to the 10- and 26-week old Group M + C rats. Male rats also had significantly more crystals than females of the same age. Male rats were affected to a greater extent than females. CONCLUSION: Younger rats experienced more severe renal failure and greater renal crystal deposition following melamine and cyanuric acid administration. However, after melamine and cyanuric acid administration cessation, crystal deposition and renal failure improved and did not cause growth arrest. Therefore, early diagnosis of melamine-associated calculi is critical.

Effect of adiponectin on kidney crystal formation in metabolic syndrome model mice via inhibition of inflammation and apoptosis.

The aims of the present study were to elucidate a possible mechanism of kidney crystal formation by using a metabolic syndrome (MetS) mouse model and to assess the effectiveness of adiponectin treatment for the prevention of kidney crystals. Further, we performed genome-wide expression analyses for investigating novel genetic environmental changes. Wild-type (+/+) mice showed no kidney crystal formation, whereas ob/ob mice showed crystal depositions in their renal tubules. However, this deposition was remarkably reduced by adiponectin. Expression analysis of genes associated with MetS-related kidney crystal formation identified 259 genes that were >2.0-fold up-regulated and 243 genes that were <0.5-fold down-regulated. Gene Ontology (GO) analyses revealed that the up-regulated genes belonged to the categories of immunoreaction, inflammation, and adhesion molecules and that the down-regulated genes belonged to the categories of oxidative stress and lipid metabolism. Expression analysis of adiponectin-induced genes related to crystal prevention revealed that the numbers of up- and down-regulated genes were 154 and 190, respectively. GO analyses indicated that the up-regulated genes belonged to the categories of cellular and mitochondrial repair, whereas the down-regulated genes belonged to the categories of immune and inflammatory reactions and apoptosis. The results of this study provide compelling evidence that the mechanism of kidney crystal formation in the MetS environment involves the progression of an inflammation and immunoresponse, including oxidative stress and adhesion reactions in renal tissues. This is the first report to prove the preventive effect of adiponectin treatment for kidney crystal formation by renoprotective activities and inhibition of inflammation and apoptosis.

The association between the incidence of urolithiasis and nutrition based on Japanese National Health and Nutrition Surveys.

To clarify the association between regional variations in urolithiasis incidence and nutrition intake, we evaluated associated data from Japanese national surveys. The incidence of urolithiasis in 12 regions of Japan was calculated from 2005 patient data obtained from 430 hospitals (n = 92,797). Nutrition intake data were obtained from the National Health and Nutrition Survey. We examined the association between urolithiasis incidence and average intake of various types of food or nutrients by region. Continuing surveys in Japan reveal fixed variations in urolithiasis incidence among geographic regions. The national average of patients with urolithiasis was estimated as 203.1 per 100,000 citizens. Regarding food, intake of fruit correlated negatively with the incidence of urolithiasis (r = -0.721, p = 0.008), while intake of eggs (r = 0.537, p = 0.072) and sugar (r = 0.475, p = 0.119) tended to positively correlate with incidence. Regarding nutrients, intake of potassium (r = -0.500, p = 0.098), vitamin K (r = -0.562, p = 0.057), and pantothenic acid (r = -0.560, p = 0.058) tended to negatively correlate with incidence. The incidence of urolithiasis is higher in geographic areas with populations having low fruit and high sugar intake.

Matrix Gla protein is involved in crystal formation in kidney of hyperoxaluric rats.

BACKGROUND: Matrix Gla protein (MGP) is a molecular determinant regulating vascular calcification of the extracellular matrix. However, it is still unclear how MGP may be involved in crystal formation in the kidney of hyperoxaluric rats. METHODS: Male Sprague-Dawley rats were divided into the hyperoxaluric group and control group. Hyperoxaluric rats were administrated by 0.75% ethylene glycol (EG) for up to 8 weeks. Renal MGP expression was detected by the standard avidin-biotin complex (ABC) method. Renal crystal deposition was observed by a polarizing microscope. Total RNA and protein from the rat kidney tissue were extracted. The levels of MGP mRNA and protein expression were analyzed by the real-time polymerase chain reaction (RT-PCR) and Western blot. RESULTS: Hyperoxaluria was induced successfully in rats. The MGP was polarly distributed, on the apical membrane of renal tubular epithelial cells, and was found in the ascending thick limbs of Henle's loop (cTAL) and the distal convoluted tubule (DCT) in hyperoxaluric rats, its expression however, was present in the medullary collecting duct (MCD) in stone-forming rats. Crystals with multilaminated structure formed in the injurious renal tubules with lack of MGP expression.MGP mRNA expression was significantly upregulated by the crystals' stimulations. CONCLUSION: Our results suggested that the MGP was involved in crystals formation by the continuous expression, distributing it polarly in the renal tubular cells and binding directly to the crystals.

Clinical impact of palliative treatment using octreotide for inoperable malignant bowel obstruction caused by advanced urological cancer.

Malignant bowel obstruction (MBO), an occasional complication in patients with advanced urological cancer, causes gastrointestinal symptoms such as nausea and vomiting leading to suffering which severely impairs quality of life (QOL). Drug therapy, especially octreotide, a synthetic analog of somatostatin, is reportedly effective in controlling the symptoms of MBO. In the present study, we administered octreotide to urological cancer patients with MBO and evaluated the improvement of subjective symptoms, oral intake, and nasogastric intubation. Fourteen terminally ill urological cancer patients suffering with MBO were included (age range 55-92, 10 male, 4 female). Octreotide was administered at 300µg/day to those patients subcutaneously as a continuous injection. Significant improvements in subjective symptoms were observed in thirteen patients (92.8%), and ten patients (71.4%) were able to resume oral intake. Four patients required nasogastric drainage before the administration of octreotide, but nasogastric intubation was discontinued in all these cases after the use of octreotide. Early initiation of octreotide resulted in better improvement of MBO symptoms, and no adverse event was observed in any of the patients. These results revealed that 300µg/day dose of octreotide is safe and effective for managing gastrointestinal symptoms of terminally ill urological cancer patients with MBO. We also recommend starting the treatment with ocreotide as soon as MBO is diagnosed.

Biomolecular mechanism of urinary stone formation involving osteopontin.

Urinary stones consist of two phases-an inorganic (mineral) phase and an organic (matrix) phase. Studies on the organic components of kidney stones have been undertaken later than those on the inorganic components. After osteopontin was identified as one of the matrix components, the biomolecular mechanism of urinary stone formation became clearer. It also triggered the development of new preventive treatments. Osteopontin expression is sporadically observed in normal distal tubular cells and is markedly increased in stone-forming kidneys. Calcium oxalate crystals adhering to renal tubular cells are incorporated into cells by the involvement of osteopontin. Stimulation of crystal-cell adhesion impairs the opening of mitochondrial permeability transition pores (mPTP) in tubular cells and produces oxidative stress, apoptosis, and osteopontin expression. Macrophages phagocytose and digest a small amount of crystals, but many crystals aggregate into a mass containing osteopontin and epithelial cell debris and are excreted into the renal tubular lumen, becoming nuclei of urinary stones. This biomolecular mechanism is similar to atherosclerotic calcification. Based on these findings, new preventive treatments have been developed. Dietary control such as low-cholesterol intake and the ingestion of antioxidative foods and vegetables have successfully reduced the 5-year recurrence rate. Osteopontin antibodies and cyclosporine A, which blocks the opening of mPTP, have markedly inhibited the expression of osteopontin and urinary stone formation in animal models.

Mitochondrial permeability transition pore opening induces the initial process of renal calcium crystallization.

Renal tubular cell injury induced by oxidative stress via mitochondrial collapse is thought to be the initial process of renal calcium crystallization. Mitochondrial collapse is generally caused by mitochondrial permeability transition pore (mPTP) opening, which can be blocked by cyclosporine A (CsA). Definitive evidence for the involvement of mPTP opening in the initial process of renal calcium crystallization, however, is lacking. In this study, we examined the physiological role of mPTP opening in renal calcium crystallization in vitro and in vivo. In the in vitro study, cultured renal tubular cells were exposed to calcium oxalate monohydrate (COM) crystals and treated with CsA (2 µM). COM crystals induced depolarization of the mitochondrial membrane potential and generated oxidative stress as evaluated by Cu-Zn SOD and 4-HNE. Furthermore, the expression of cytochrome c and cleaved caspase 3 was increased and these effects were prevented by CsA. In the in vivo study, Sprague-Dawley rats were administered 1% ethylene glycol (EG) to generate a rat kidney stone model and then treated with CsA (2.5, 5.0, and 10.0 mg/kg/day) for 14 days. EG administration induced renal calcium crystallization, which was prevented by CsA. Mitochondrial collapse was demonstrated by transmission electron microscopy, and oxidative stress was evaluated by measuring Cu-Zn SOD, MDA, and 8-OHdG generated by EG administration, all of which were prevented by CsA. Collectively, our results provide compelling evidence for a role of mPTP opening and its associated mitochondrial collapse, oxidative stress, and activation of the apoptotic pathway in the initial process of renal calcium crystallization.

Role of osteopontin in early phase of renal crystal formation: immunohistochemical and microstructural comparisons with osteopontin knock-out mice.

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.

[New therapy using bisphosphonate for urolithiasis].

Osteoporosis is characterized by a reduction in bone mineral density (BMD) . Reduced BMD has been reported in urolithiasis patients with hypercalciuria, as well as in those with normocalciuria. Bisphosphonates potently inhibit bone resorption and are used in the management of osteoporosis. We show the ability of bisphosphonate to prevent the recurrence of urolithiasis. Bisphosphonate reduced the excretion of urinary calcium and the ion activity product index of calcium phosphate in urolithiasis patients, and prevented urinary stone formation in long-term bed rest test. The results suggest that ALN not only improves osteoporosis but also reduces the risk of calcium stone formation. Bisphosponates are believed to reduce the urinary excretion of calcium by improvement of bone metabolism, and to have a direct effect in the prevention of urolithiasis.

Crucial role of the cryptic epitope SLAYGLR within osteopontin in renal crystal formation of mice.

Osteopontin plays a crucial role in the formation of renal calcium crystals, which are primarily induced by renal tubular cell injury, especially mitochondrial damage. We have previously shown that the impaired Arg-Gly-Asp (RGD) sequence of osteopontin inhibits renal crystal formation by using OPN-transgenic mice and OPN-knockout (OPN-KO) mice. Here, we investigated the effects of an antimurine osteopontin antibody (35B6-Ab) that specifically reacts with the (162) SLAYGLR(168) sequence, which is exposed by thrombin cleavage and is located adjacent to the RGD sequence, on renal crystal formation. Renal crystals induced by daily administration of glyoxylate over 9 days (from days 1 to 9) in a murine model were sporadically detected in the renal tubular cells at the corticomedullary junction, where thrombin-cleaved osteopontin expression was also coincidentally detected. On days 0, 3, 6, and 9, 35B6-Ab administration inhibited renal crystal formation and induced significant morphological changes in a dose-dependent manner (250, 500, and 1000 µg per mouse). Scanning electron microscopy showed that the crystals in 35B6-Ab-treated mice were aberrantly formed and their density was low; in contrast, the crystals in untreated mice that were not administered 35B6-Ab had a radial pattern of growth (rosette petal-like crystals), and their density was high. Microstructure analysis of renal tubular cells by transmission electron microscopy revealed that untreated mice showed collapsed mitochondria in the flattened cytoplasm of renal tubular cells, unlike the corresponding structures in 35B6-Ab-treated mice, in which renal tubular cell injury was inhibited. In vitro, 35B6-Ab was found to inhibit the attachment of (14) C-labeled crystals to renal tubular culture cells and reduce morphological damage to these cells. We conclude that thrombin-cleaved osteopontin plays an important role in formation of renal calcium crystals and that 35B6-Ab contributes to the remarkable inhibition of early-stage renal crystal formation by preventing renal tubular cell injury and crystal-cell attachment.

Efficacy of selective α1A adrenoceptor antagonist silodosin in the medical expulsive therapy for ureteral stones.

Recently, we reported that α1A adrenoceptor (AR) is the main participant in phenylephrine-induced human ureteral contraction. We therefore decided to carry out a prospective randomized study to evaluate the effects of silodosin, a selective α1A AR antagonist, as a medical expulsive therapy for ureteral stones. A total of 187 male patients, who were referred to our department for the management of symptomatic unilateral ureteral calculi of less than 10 mm, were randomly divided into two groups: group A (92 patients), who were instructed to drink 2 L of water daily, and group B (95 patients), who received the same instruction and were also given silodosin (8 mg/daily) for a maximum of 8 weeks. Expulsion rate, mean expulsion time and need for analgesics were examined. Overall, the mean expulsion time was 15.19 ± 7.14 days for group A and 10.27 ± 8.35 days for group B (P = 0.0058). In cases involving distal ureteral stones, the mean expulsion time was 13.40 ± 5.90 and 9.29 ± 5.91 days, respectively (P = 0.012). For stones of 1-5 mm in diameter, the mean expulsion time was 14.28 ± 6.35 and 9.56 ± 8.45 days, respectively (P = 0.017). For stones of 6-9 mm in diameter, the stone expulsion rate was 30.4% and 52.2% (P = 0.036), and the mean expulsion time was 21.00 ± 9.9 and 11.33 ± 8.31 days, respectively (P = 0.038). Herein, we report the first on silodosin in the management of ureteral lithiasis. Our findings suggest that silodosin might have potential as a medical expulsive therapy for ureteral stones.

The role of long-term loading of cholesterol in renal crystal formation.

We studied the effects of cholesterol load on urinary stone in rats receiving a standard diet or a high fat diet. Sixty male rats were randomized to two groups and were fed either a standard diet (SD group) or a high fat diet (HFD group) for 8 weeks. Then the two groups were further divided into four groups. SD group, HFD group, SD + EG group (with standard diet + ethylene glycol administration for two weeks), and HFD + EG group (with high fat diet + ethylene glycol administration). The starting date of EG administration was considered to be week 0. Twenty-four-hour urine samples were collected in week 0, week 1, and week 2, and oxalate excretion and citrate excretion were measured by capillary electrophoresis analyzer The excretion of phosphorus, magnesium, and creatinine for 24 hours was measured using an automated analyzer Serum sodium, potassium, chloride, calcium, phosphate, magnesium, creatinine, total cholesterol, triglyceride, HDL-cholesterol and glucose were determined using an automated analyzer The kidney tissues were obtained to perform hematoxyline-eosine staining and Pizzolato's staining to detect oxalate-containing crystals. The average body weight in HFD groups and HFD + EG group in week 0 was significantly higher than that of SD group and SD + EG group. The calcium oxalate crystal deposition was not observed in all groups in week 0. HFD + EG group in week 1 had sporadically calcium oxalate crystal deposition in renal distal tubular cells and tubular lumens. In week 2, the number of crystal deposition in HFD + EG group was increased remarkably. The crystals were slightly observed in SD + EG group in week 2. The excretion of urinary calcium and phosphate in HFD group and HFD + EG group was significantly higher than that of the SD group and SD + EG group in week 0. The amount of urinary citrate excretion in the SD group and SD + EG group showed a significantly higher value compared with that of the HFD group and HFD + EG group in week 0. The level of serum total cholesterol in the HFD group and HFD + EG group was higher compared to that in the SD group and SD + EG group. The serum triglyceride level was not significantly different in the four groups in week 0. Interestingly, the level of triglyceride of EG administration groups (SD + EG and HFD + EG group) was significantly higher than that in EG no-administration groups (SD group and HFD group) in week 1 and week 2. The serum glucose level in the HFD group and HFD + EG group was significantly higher than that in the SD group and SD + EG group in week 0. In week 2, the glucose level of EG administration groups (HDF + EG group and SD + EG group) was significantly lower than that of EG no-administration groups (HFD group and SD group). In conclusion, this result suggested that long-term loading of cholesterol could increase renal calcium stone formation.

[Functional domains of osteopontin stimulate renal crystal formation: analysis of OPN-transgenic mice].

Osteopontin (OPN) has been described to play a nonredundant role in the formation of renal crystals. This biological activity of OPN may be attributed to its characteristic structure, which includes 2 calcium binding sites, Arg-Gly-Asp (RGD) sequences. To test this hypothesis, we evaluated wild-type mice (WT group), OPN-knockout mice (KO group), and two types of transgenic mice : (1) one type carrying a transgene in which the sequences coding for the 2 calcium-binding sites of the OPN were deleted (CaX group) and (2) the other type carrying a transgene in which the sequence that codes for the RGD sequence of the OPN was modified to one that codes for Arg-Gly-Glu (RGE ; RGE group). Changes occurring after intraperitoneal injection of glyoxylate for 9 d were analyzed. The amount of crystals deposited was the greatest in mice of the WT group and the least in those of the KO group. The number of crystal deposits in mice of the RGE and KO groups was approximately the same. Microscopic observations revealed that the crystal nuclei in mice in the CaX group were stratified and exhibited a disordered pattern ; this pattern was dissimilar to that observed in the mice in the WT and RGE groups, wherein the crystal nuclei exhibited a rosette petal-like radial pattern. The results indicate the possibility that each domain contributes to the mechanism by which OPN stimulates crystal formation.

Renal macrophage migration and crystal phagocytosis via inflammatory-related gene expression during kidney stone formation and elimination in mice: Detection by association analysis of stone-related gene expression and microstructural observation.

Mice have a strong ability to eliminate renal calcium oxalate crystals, and our previous examination indicated a susceptibility in which monocyte-macrophage interaction could participate in the phenomenon. To clarify the macrophage-related factors playing roles in the prevention of crystal formation in mouse kidneys, morphologic and expression studies based on microarray pathway analysis were performed. Eight-week-old male C57BL/6N mice were administered 80 mg/kg of glyoxylate by daily intraabdominal injection for 15 days, and the kidneys were extracted every 3 days for DNA microarray analysis. Based on the raw data of microarray analysis, pathway analyses of inflammatory response demonstrated macrophage activation through the increased expression of chemokine (C-X-C) ligand 1, fibronectin 1, and major histocompatability (MHC) class II. Association analysis of related gene expression values by quantitative reverse transcription polymerase chain reaction (RT-PCR) indicated the high association of chemokine (C-C) ligand 2, CD44, colony-stimulating factor 1, fibronectin 1, matrix gla protein, secreted phosphoprotein 1, and transforming growth factor ß1 (TGF-ß1) with the amount of both renal crystals and F4/80, a macrophage marker. Immunohistochemically, interstitial macrophages increased during the experimental course, and CD44 and MHC class II were upregulated around crystal-formation sites. Ultrastructural observation of renal macrophages by transmission electron microscopy indicated interstitial macrophage migration with the phagocytosis of crystals. In conclusion, increased expression of inflammation-related genes of renal tubular cells induced by crystal formation and deposition could induce monocyte-macrophage migration and phagocytosis via the interaction of CD44 with osteopontin and fibronectin. Such crystal-removing ability of macrophages through phagocytosis and digestion might become a new target for the prevention of stone formation.

Renal tubular epithelial cell injury and oxidative stress induce calcium oxalate crystal formation in mouse kidney.

OBJECTIVES: To clarify the role of renal tubular cell (RTC) injury and oxidative stress in the early stage of renal calcium oxalate crystal formation in a mouse model. METHODS: Daily intra-abdominal injections of glyoxylate (1.35 mmol/kg/day) into 8-week-old mice were carried out over 6 days. Kidneys were extracted before and at 6, 12 and 24 h and 3 and 6 days after glyoxylate injection. Crystal formation was detected using Pizzolato staining and polarized light optical microscopy. Immunohistochemical staining and western blotting of superoxide dismutase, and 4-hydroxynonenal and malondialdehyde were carried out in order to observe oxidative stress and lipid peroxidation, respectively. RTC microstructural damage and crystal nuclei formation were observed using transmission electron microscopy. To ameliorate RTC injury, mice were treated with green tea 1 week before and 1 week after glyoxylate administration. The number of crystals and RTC damage were observed and comparisons were made between glyoxylate-treated mice with and without green tea administration. RESULTS: Oxidative stress and lipid peroxidation were observed after 6 h. Crystal nuclei containing collapsed mitochondria and fallen microvilli appeared in the renal distal tubular lumen after 24 h. Crystals occupying the tubular lumen were detected on day 3. The number of crystals in mice receiving green tea was significantly lower than in those receiving glyoxylate alone. CONCLUSIONS: RTC injury, especially mitochondrial damage, and oxidative stress induce the early stage of calcium oxalate crystal formation in mice.

Alendronate reduces the excretion of risk factors for calcium phosphate stone formation in postmenopausal women with osteoporosis.

OBJECTIVE: Osteoporosis is associated with the pathogenesis and risk of urolithiasis, which is higher among postmenopausal women (as opposed to premenopausal). Bisphosphonates potently inhibit bone resorption, and are used in the management of bone disease. We investigated the ability of a bisphosphonate to prevent calcium stone formation. METHODS: We studied 12 postmenopausal women (63.8 +/- 7.3 years) who were not receiving osteoporosis therapy, and had stones comprised of calcium phosphate (CaP; n = 3), calcium oxalate (CaOx; n = 3) and CaP + CaOx (n = 6). We measured bone mineral density (BMD), serum and urinary values in 24-hour urine specimens before and 3 months after the oral administration of 5 mg/day of alendronate (ALN). The indexes of the ionic activity product of calcium oxalate, AP(CaOx), and of calcium phosphate, AP(CaP), were estimated using the Tiselius method. RESULTS: ALN significantly reduced the AP(CaP) index (1.53 +/- 1.37 to 0.89 +/- 0.81, p <0.05). Urinary calcium, oxalate, phosphate and the AP(CaOx) index did not significantly change. BMD improved in 11 of the 12 patients. Urinary stones did not develop in any of the patients during the course of the study. CONCLUSION: The results suggested that ALN not only improves BMD and osteoporosis, but also reduces the risk of calcium phosphate stone formation in postmenopausal women.

Genome-wide analysis of genes related to kidney stone formation and elimination in the calcium oxalate nephrolithiasis model mouse: detection of stone-preventive factors and involvement of macrophage activity.

We previously established a mouse kidney stone formation model and showed that mice have a higher tolerance to stone formation than rats. Furthermore, we showed that the generated calcium oxalate crystal deposits could be eliminated after several days. This study investigated the transcriptome of stone formation and elimination in the mouse kidney based on gene selection using a microarray technique. Eight-week-old male C57BL/6N mice were administered 80 mg/kg glyoxylate for 15 days, and kidney calcium oxalate crystal depositions had increased by day 6; thereafter, depositions decreased gradually and had almost disappeared by day 15. On microarray analysis, mRNA expression in the crystal-formed kidneys showed the significant expression of 18,064 genes. Thirty-one, 21, and 25 genes showed at least a 2-fold increased expression during the experimental course (days 3-15), stone formation phase-specific (days 3-6), and stone elimination phase-specific (days 9-15) stages, respectively. Among these genes, those related to chemotaxis and monocyte/macrophage activation were identified. Gene ontology analysis to identify overexpressed genes highlighted categories related to inflammation, immune reactions and the complement activation pathway. Quantitative PCR of 17 previously reported stone-related genes with a significant expression on microarray analysis showed significantly increased chemokines, stone matrix proteins, and their receptors; the significant decrease of several types of transporters and superoxide dismutase; and the persistently high expression of Tamm-Horsfall protein throughout the experiment. In conclusion, inflammation and immune reactivity through macrophage migration are involved in stone formation and elimination in mouse kidneys.

NF-kappaB activation in renal tubular epithelial cells by oxalate stimulation.

OBJECTIVES: The transcription factor nuclear factor-kappaB (NF-kappaB) is involved in inflammatory and immune responses through the induction of various cytokines and growth factors. Recently, the coordinated action of NF-kappaB and activator protein-1 was reported in osteopontin (OPN) expression. In the present study, we demonstrated that oxalate induces OPN expression by activating NF-kappaB in renal tubular cells. Furthermore, we investigated the inhibitory effect of N-acetyl-L-cysteine (NAC) on NF-kappaB activation in the human renal tubular cell line. METHODS: All of the experiments were carried out using human kidney-2 cells, which are human proximal tubular epithelial cells immortalized by transduction with the human papillomavirus 16E6/E7 gene. The time-dependent extraction of total protein was performed after the uptake of 0.5 mM oxalate by the cells. The NF-kappaB activation and OPN expression were examined by western blotting and immunocytochemistry. RESULTS: As a result of oxalate stimulation, the amount of p65 subunit in the nucleus increased significantly (P < 0.05), and NAC significantly inhibited the translocation of p65 into the nucleus (P < 0.05). CONCLUSION: These observations indicate that NAC can be used as a drug to prevent stone formation.