Significance of prostate-specific antigen kinetics after three-dimensional conformal radiotherapy with androgen deprivation therapy in patients with localized prostate cancer.

BACKGROUND: To evaluate the relationship between biochemical recurrence and post-radiation prostate-specific antigen (PSA) kinetics in patients with localized prostate cancer treated by radiotherapy with various durations of androgen deprivation therapy (ADT). METHODS: We reviewed our single-institution, retrospectively maintained data of 144 patients with T1c-T3N0M0 prostate cancer who underwent three-dimensional conformal radiotherapy (3D-CRT) between December 2005 and December 2015 and 113 patients were fulfilled the inclusion criteria. In this cohort, 3D-CRT was delivered with a dose in the range from 70.0 to 72.0 Gy with ADT. All patients received ADT as concurrent regimens. Biochemical recurrence was defined on the basis of the following: "PSA nadir + 2.0 ng/ml or the clinical judgement of attending physicians". Kaplan-Meier, log-rank, and Cox regression analyses were carried out. RESULTS: The median follow-up period was 54.0 months. The median duration of ADT was 17 months (interquartile range, 10-24 months). There was a trend toward statistical significant correlation between post-radiation PSA decline rate of ≥ 90% and PSA recurrence (p = 0.056). The same correlation could be observed in D'Amico high-risk patients (p = 0.036). However, it was not observed between PSA nadir and PSA recurrence (p = 0.40) in univariate analysis. Furthermore, multivariate analysis showed that post-radiation PSA decline rate of ≥ 90% was a significant predictor of biochemical recurrence in patients who received radiotherapy with various durations of ADT (p = 0.044). CONCLUSIONS: Post-radiation PSA decline rate of ≥ 90% was a prognostic factor for biochemical recurrence in localized prostate cancer patients received 3D-CRT with various durations of ADT.

Possible effect of lysophosphatidic acid on cell proliferation and involvement of lysophosphatidic acid and lysophosphatidic acid receptors in mechanical stretch-induced mitogen-activated protein kinase.

OBJECTIVES: To determine whether lysophosphatidic acid activates the mitogen-activated protein kinase and increases DNA synthesis in human bladder smooth muscle cells, and to examine the involvement of lysophosphatidic acid and lysophosphatidic acid receptor in mechanical stretch-induced mitogen-activated protein kinase activation in cultured human bladder smooth muscle cells. METHODS: TaqMan reverse transcription polymerase chain reaction was used to determine the mRNA expression levels of six lysophosphatidic acid receptor subtypes. Mitogen-activated protein kinase activity enhanced by either lysophosphatidic acid or mechanical stretch was measured by western blotting. The effect of lysophosphatidic acid on DNA synthesis was assessed by 5-bromo-2'-deoxy-uridine incorporation assay. RESULTS: Lysophosphatidic acid 1 subtype mRNA was predominantly expressed (96%). Lysophosphatidic acid activated the mitogen-activated protein kinase in a concentration-dependent manner. C-jun NH2 -terminal kinase showed the highest activity among the three subsets of the mitogen-activated protein kinase family members (c-jun NH2 -terminal kinase, extracellular signal-regulated kinases, p38). Lysophosphatidic acid also increased incorporation of 5-bromo-2'-deoxy-uridine. These responses were suppressed by Ki16425 (lysophosphatidic acid receptor antagonist). Mechanical stretch mainly induced c-jun NH2 -terminal kinase activation. This activation was partially inhibited by Ki16425. CONCLUSIONS: Lysophosphatidic acid might activate the c-jun NH2 -terminal kinase component of the mitogen-activated protein kinase family and DNA synthesis through lysophosphatidic acid receptors (presumably, through lysophosphatidic acid 1) in human bladder smooth muscle cells. The present study also implicates the involvement of lysophosphatidic acid and lysophosphatidic acid receptors in mechanical stretch-induced c-jun NH2 -terminal kinase activation. Lysophosphatidic acid receptor can be partially activated by mechanical stretching through lysophosphatidic acid-dependent or independent mechanism.

Involvement of stretch-induced Rho-kinase activation in the generation of bladder tone.

AIMS: The present study investigated the role of the Rho-kinase (ROK) pathway in the maintenance of bladder tone during the storage phase, and its effects on bladder compliance. METHODS: Muscle strips from isolated rat bladder (detrusor strips) were used to evaluate the effects of the ROK inhibitors Y-27632 and HA-1077 on resting tension, which is independent of G-protein coupled pathways. Stretch-induced ROK activation was assessed by measuring phosphorylation of MYPT1 (myosin phosphatase targeting subunit) using Western blotting. The effect of ROK inhibitors on bladder compliance during bladder filling was assessed in an in vitro whole bladder model. RESULTS: Y-27632 and HA-1077 caused concentration-dependent relaxation of detrusor strips. Stretch increased MYPT1-p[Thr853] levels by approximately 1.5-fold in normal Krebs buffer. The ROK inhibitor Y-27632 abolished the stretch-induced increase and reduced the level of MYPT1-p[Thr853] to <50% of the basal values in normal Krebs buffer. Stretch-induced phosphorylation of MYPT1 was independent of Ca(2+) originating from either extracellular or intracellular stores. When tested in the isolated whole rat bladder model, HA-1077 significantly increased bladder compliance at both 3 and 10 µM. CONCLUSIONS: This study demonstrates that the ROK pathway is constitutively active and stretch further activates the ROK pathway, which contributes to the generation of bladder tone, thereby affecting bladder compliance.

Involvement of angiotensin II type 1 receptor on pathological remodeling and dysfunction in obstructed bladder.

OBJECTIVES: To determine whether long-term administration of an angiotensin II type 1 receptor antagonist improves morphology and function in obstructed bladders. METHODS: Male Sprague-Dawley rats underwent surgery to produce bladder outlet obstruction (bladder outlet obstruction group; n = 32) or sham surgery (sham group; n = 16). A total of 2 weeks later, 16 bladder outlet obstruction-rats were given the AT1 antagonist, candesartan, subcutaneously (candesartan group) using an osmotic pump for 4 weeks; the remaining bladder outlet obstruction-rats received vehicle (bladder outlet obstruction group). A total of 6 weeks after surgery, we compared continuous cystometry, bladder weight, strip contraction, histology and messenger ribonucleic acid expression of growth factors, nicotinamide adenine dinucleotide phosphate oxidase 1 and renin-angiotensin system components among the three groups. RESULTS: Bladder weights markedly increased with bladder outlet obstruction (578 ± 159 mg), and candesartan (344 ± 111 mg) suppressed this increase. Micturition pressure, which was significantly higher with bladder outlet obstruction, was unaffected by candesartan. The shortened micturition interval and decreased micturition volume with bladder outlet obstruction were significantly prolonged and increased by candesartan. Candesartan also significantly decreased residual urine. Histologically, the collagen fiber-to-muscle ratio was significantly increased with bladder outlet obstruction (0.85 ± 0.25) compared with the sham group (0.53 ± 0.18); this increase was suppressed by candesartan (0.49 ± 0.21). The messenger ribonucleic acid expression of heparin-binding epidermal growth factor-like growth factor, transforming growth factor-ß1 and nicotinamide adenine dinucleotide phosphate oxidase 1 significantly increased with bladder outlet obstruction, but it was significantly reduced by candesartan. Compared with the bladder outlet obstruction group, candesartan increased the maximal contraction of bladder strips for all stimuli except for angiotensin II. CONCLUSION: These findings suggest that bladder angiotensin II type 1 receptors contribute to the pathophysiology of remodeling and dysfunction in obstructed bladder.

The Association between Severity of Atherosclerosis and Lower Urinary Tract Function in Male Patients with Lower Urinary Tract Symptoms.

OBJECTIVES: The present study was undertaken to investigate the association between the severity of atherosclerosis and lower urinary tract function in male patients with lower urinary tract symptoms. METHODS: Male patients with lower urinary tract symptoms were examined with routine investigation. The severity of atherosclerosis was assessed by ultrasound examination of carotid artery. Patients were divided into two groups: control group and atherosclerosis group. The voiding function and storage function were compared between the two groups. RESULTS: A total of 50 men (69.9 ± 9.1 years [mean ± standard deviation]) entered the study. There was no significant difference in age distribution (control group: 68.7 ± 7.6 years; atherosclerosis group: 72.5 ± 9.7 years) and prostate volume (control group: 26.5 ± 17.3 mL; atherosclerosis group: 22.2 ± 11.0 mL) between the two groups. In the voiding parameters, maximum flow rate in the atherosclerosis group (13.4 ± 5.5 mL/s, P < 0.05) was significantly lower than that in the control group (16.7 ± 7.7 mL/s). Postvoid residual urine volume showed no significant difference between the two groups. In the storage parameters, voided volume was significantly reduced in the atherosclerosis group (161.8 ± 46 mL, P < 0.05), as compared to control group (201.1 ± 78 mL). Moreover, daytime frequency was 7.13 ± 3.02 times in the control group, and significantly higher in the atherosclerosis group (8.75 ± 2.50 times, P < 0.05). CONCLUSION: Development of atherosclerosis impairs both voiding and storage function independently of age, suggesting atherosclerosis leads to lower urinary dysfunction.

Long-term administration of prazosin improves bladder storage function: results from a study in spontaneously hypertensive rats.

OBJECTIVES: To investigate the effects of long-term administration of the α(1) -adrenoceptor antagonist prazosin on afferent inputs from the lower urinary tract (LUT). METHODS: Twenty female spontaneously hypertensive rats (SHR) were randomized to receive a 4-week course of prazosin (0.12 mg/kg per day) or vehicle; 10 female Wistar-Kyoto (WKY) rats were given vehicle. Prazosin or vehicle was administered via an osmotic pump. The effect of prazosin on urodynamic parameters was determined by continuous cystometry in conscious animals. After cystometry, rats were killed and c-fos expression in the dorsal horn of the L6 spinal cord was measured by immunohistochemistry. RESULTS: The bladder contraction interval was significantly shorter in untreated SHR compared with WKY rats (2.36 ± 0 vs 4.27 ± 0.12 min, respectively; P < 0.05) and cystometric capacity was decreased significantly in SHR compared with WKY rats. L6 spinal cord c-Fos expression was also significantly greater in SHR than WKY rats. The administration of prazosin significantly increased the micturition interval (4.07 ± 0.58 min; P < 0.05) and bladder capacity, but it did not affect micturition pressure. In SHR, the number of c-Fos-positive neurons was significantly lower following the administration of prazosin compared with vehicle. CONCLUSIONS: Increased afferent input from the LUT may induce an increase in urinary frequency in SHR. Furthermore, long-term administration of prazosin can exert inhibitory effects on afferent pathways from the LUT during the storage phase. Reductions of afferent input can result in increased bladder capacity and increased micturition interval.

Obstruction alters muscarinic receptor-coupled RhoA/Rho-kinase pathway in the urinary bladder of the rat.

AIMS: The present study investigated the effects of the bladder outlet obstruction (BOO) on the muscarinic receptor (MR)-coupled RhoA/Rho-kinase (ROK) pathway in the detrusor smooth muscle of the rat. METHODS: Detrusor muscle samples were obtained from bladders after 4 weeks of BOO and also from sham-operated control rats. Contractile responses to electrical field stimulation (EFS) and 1 microM carbachol (Cch) were determined in isolated detrusor strips. The effects of the ROK inhibitor Y-27632 on the Cch-induced phasic and sustained contractions were evaluated. Western blotting was used to determine the relative levels of RhoA expression and ROK isoform expression. RESULTS: Bladder weight increased significantly after 4 weeks of BOO. Contractile responses to EFS decreased significantly in detrusor muscle from the obstructed bladder. Cch (1 microM) induced a biphasic response consisting of an initial phasic contraction followed by a sustained contraction. Y-27632 attenuated the phasic and sustained contractions induced by Cch in both control and obstructed bladders. However, BOO caused a significant increase in contractile force during the sustained phase of the contractions induced by Cch. An inhibitory effect of Y-27632 on the sustained responses to Cch was significantly enhanced in the obstructed bladder. In accordance with the functional study, the expression of RhoA and ROK isoforms (both alpha and beta) at the protein level significantly increased in the obstructed bladder. CONCLUSIONS: These results suggest that the enhanced MR-coupled RhoA/ROK pathway contributes to the maintenance of contractile force in the obstructed bladder, as a compensatory mechanism for expelling the urine against the obstruction.