Changes of Bladder M1,3 Muscarinic Receptor Expression in Rats Fed with Short-Term/Long-Term High-Fat Diets.

OBJECTIVES: To investigate the effect of high-fat diet (HFD) on bladder M1,3 muscarinic receptor expression and contractile function in the rat. METHODS: Eight-week-old male rats were divided into two groups including one with HFD for 8 weeks (short-term) and the other for 24 weeks (long-term). Each group was compared to age-matched rats fed with normal chow as controls. The body weight, food intake amount and blood biochemistry were monitored. Bladder muscle contractile responses to acetylcholine (0.1-10 µM), bethanechol (10 µM) and KCl (50 mM) were studied in an organ bath set-up. Bladder M1 and M3 muscarinic receptor protein expressions were measured by Western blotting analysis. RESULTS: Increase in body weight as well as blood triglyceride, cholesterol and sugar levels compared to controls were noted in both 8- and 24-week HFD rats. Eating appetite change with increased food and water intakes was noted in the HFD rats. Significantly decreased bladder contractile responses to acetylcholine and bethanechol were shown in both HFD groups. On the other hand, decreased bladder contractile response to KCl was demonstrated in the 24-week group but not the 8-week group. The expressions of bladder M1 and M3 muscarinic receptor proteins were significantly and progressively decreased by HFD feeding from 8 to 24 weeks. CONCLUSIONS: High-fat diet induces obesity and polyphagia in rats. Short-term and long-term HFD feeding decrease rat bladder M1 and M3 receptor expressions as well as contractile responses to the agonistic stimulation. In addition, bladder muscle dysfunction develops after long-term HFD feeding.

Associations between interventions for urolithiasis and urinary tract cancer among patients in Taiwan: The effect of early intervention.

The aim of this study was to investigate cancer risk in patients with a history of urolithiasis and to determine whether intervention for calculi attenuated the risk of subsequent urinary tract cancer (UTC).Using data from the National Health Insurance Research Database in Taiwan, we performed a nationwide cohort study enrolling participants (n = 42,732) aged > 30 years who were diagnosed with urinary tract calculi between 2000 and 2009. Age- and gender-matched insured individuals (n = 213,660) found in the health service records over the same period were recruited as the control group. The Cox proportional hazards model and competing risks regression model were used to examine the relationship between urolithiasis and UTC, as well as whether early intervention for urolithiasis decreased the subsequent cancer risk relative to late intervention.Participants with a previous diagnosis of urolithiasis (n = 695) had a 1.82-fold (95% CI: 1.66-1.99, P < 0.001) increased risk of developing UTC. Furthermore, the risk of UTC associated with urolithiasis was higher in women (adjusted HR: 2.43, 95% CI: 1.94-3.05) than in men (adjusted HR: 1.72, 95% CI: 1.55-1.90). When stratified by cancer site, the adjusted HR for bladder, renal pelvis/ureter, renal, and prostate cancers were 1.94 (95% CI: 1.62-2.33), 2.94 (95% CI: 2.24-3.87), 2.94 (95% CI: 2.29-3.77), and 1.45 (95% CI: 1.27-1.65), respectively. Patients who received interventions for urolithiasis within 3 months of detection had a decreased risk of subsequent UTC (adjusted HR: 0.53, 95% CI: 0.40-0.71, P < 0.001).The present study demonstrated that urolithiasis increased the risk of subsequent UTC, especially upper UTC. Hence, it is recommended that physicians administer the appropriate interventions as early as possible upon diagnosis of urolithiasis.

Blockade of the N-Methyl-D-Aspartate Glutamate Receptor Ameliorates Lipopolysaccharide-Induced Renal Insufficiency.

N-methyl-D-aspartate (NMDA) receptor activation in rat kidney reduces renal perfusion and ultrafiltration. Hypoperfusion-induced ischemia is the most frequent cause of functional insufficiency in the endotoxemic kidney. Here, we used non-hypotensive rat model of lipopolysaccharide-induced endotoxemia to examine whether NMDA receptor hyperfunction contributes to acute kidney injury. Lipopolysaccharide-induced renal damage via increased enzymuria and hemodynamic impairments were ameliorated by co-treatment with the NMDA receptor blocker, MK-801. The NMDA receptor NR1 subunit in the rat kidney mainly co-localized with serine racemase, an enzyme responsible for synthesizing the NMDA receptor co-agonist, D-serine. The NMDA receptor hyperfunction in lipopolysaccharide-treated kidneys was demonstrated by NR1 and serine racemase upregulation, particularly in renal tubules, and by increased D-serine levels. Lipopolysaccharide also induced cell damage in cultured tubular cell lines and primary rat proximal tubular cells. This damage was mitigated by MK-801 and by small interfering RNA targeting NR1. Lipopolysaccharide increased cytokine release in tubular cell lines via toll-like receptor 4. The release of interleukin-1ß from these cells are the most abundant. An interleukin-1 receptor antagonist not only attenuated cell death but also abolished lipopolysaccharide-induced NR1 and serine racemase upregulation and increases in D-serine secretion, suggesting that interleukin-1ß-mediated NMDA receptor hyperfunction participates in lipopolysaccharide-induced tubular damage. The results of this study indicate NMDA receptor hyperfunction via cytokine effect participates in lipopolysaccharide-induced renal insufficiency. Blockade of NMDA receptors may represent a promising therapeutic strategy for the treatment of sepsis-associated renal failure.

H2O2 generated by NADPH oxidase 4 contributes to transient receptor potential vanilloid 1 channel-mediated mechanosensation in the rat kidney.

The presence of NADPH oxidase (Nox) in the kidney, especially Nox4, results in H2O2 production, which regulates Na(+) excretion and urine formation. Redox-sensitive transient receptor potential vanilloid 1 channels (TRPV1s) are distributed in mechanosensory fibers of the renal pelvis and monitor changes in intrapelvic pressure (IPP) during urine formation. The present study tested whether H2O2 derived from Nox4 affects TRPV1 function in renal sensory responses. Perfusion of H2O2 into the renal pelvis dose dependently increased afferent renal nerve activity and substance P (SP) release. These responses were attenuated by cotreatment with catalase or TRPV1 blockers. In single unit recordings, H2O2 activated afferent renal nerve activity in response to rising IPP but not high salt. Western blots revealed that Nox2 (gp91(phox)) and Nox4 are both present in the rat kidney, but Nox4 is abundant in the renal pelvis and originates from dorsal root ganglia. This distribution was associated with expression of the Nox4 regulators p22(phox) and polymerase δ-interacting protein 2. Coimmunoprecipitation experiments showed that IPP increases polymerase δ-interacting protein 2 association with Nox4 or p22(phox) in the renal pelvis. Interestingly, immunofluorescence labeling demonstrated that Nox4 colocalizes with TRPV1 in sensory fibers of the renal pelvis, indicating that H2O2 generated from Nox4 may affect TRPV1 activity. Stepwise increases in IPP and saline loading resulted in H2O2 and SP release, sensory activation, diuresis, and natriuresis. These effects, however, were remarkably attenuated by Nox inhibition. Overall, these results suggest that Nox4-positive fibers liberate H2O2 after mechanostimulation, thereby contributing to a renal sensory nerve-mediated diuretic/natriuretic response.

Chinese nomogram to predict probability of positive initial prostate biopsy: a study in Taiwan region.

Several nomograms for prostate cancer detection have recently been developed. Because the incidence of prostate cancer is lower in Chinese men, nomograms based on other populations cannot be directly applied to Chinese men. We, therefore, developed a model for predicting the probability of a positive initial prostate biopsy using clinical and laboratory data from a Chinese male population. Data were collected from 893 Chinese male referrals, 697 in the derivation set and 196 in the external validation set, who underwent initial prostate biopsies as individual screening. We analyzed age, prostate volume, total prostate-specific antigen (PSA), PSA density (PSAD), digital rectal examinations (DRE) and transrectal ultrasound (TRUS) echogenicity. Logistic regression analysis estimated odds ratio, 95% confidence intervals and P values. Independent predictors of a positive biopsy result included advanced age, small prostate volume, elevated total PSA, abnormal digital rectal examination, and hyperechoic or hypoechoic TRUS echogenicity. We developed a predictive nomogram for an initial positive biopsy using these variables. The area under the receiver-operating characteristic curve for the model was 88.8%, which was greater than that of the prediction based on total PSA alone (area under the receiver-operating characteristic curve 74.7%). If externally validated, the predictive probability was 0.827 and the accuracy rate was 78.1%, respectively. Incorporating clinical and laboratory data into a prebiopsy nomogram improved the prediction of prostate cancer compared with predictions based solely on the individual factors.

Activation of muscarinic M-1 cholinoceptors by curcumin to increase glucose uptake into skeletal muscle isolated from Wistar rats.

Curcumin, an active principle contained in rhizome of Curcuma longa, has been mentioned to show merit for diabetes through its anti-oxidative and anti-inflammatory properties. In the present study, we found that curcumin caused a concentration-dependent increase of glucose uptake into skeletal muscle isolated from Wistar rats. This action was inhibited by pirenzepine at concentration enough to block muscarinic M-1 cholinoceptor (M(1)-mAChR). In radioligand binding assay, the binding of [(3)H]-pirenzepine was also displaced by curcumin in a concentration-dependent manner. In the presence of inhibitors for PLC-PI3K pathway, either U73122 (phospholipase C inhibitor) or LY294002 (phosphoinositide 3-kinase inhibitor), curcumin-stimulated glucose uptake into skeletal muscle was markedly reduced. In Western blotting analysis, the membrane protein level of glucose transporter 4 (GLUT4) increased by curcumin was also reversed by blockade of M(1)-mAChR or PLC-PI3K pathway in a same manner. In conclusion, the obtained results suggest that curcumin can activate M(1)-mAChR at concentrations lower than to scavenge free radicals for increase of glucose uptake into skeletal muscle through PLC-PI3-kinase pathway.