Shih-Chieh Chueh

DUAL EFFECTS OF OUABAIN ON THE REGULATION OF PROLIFERATION AND APOPTOSIS IN HUMAN PROSTATIC SMOOTH MUSCLE CELLS

PURPOSE To elucidate the role of ouabain in the pathophysiology of benign prostatic hyperplasia we examined the effects of ouabain on the proliferation and apoptosis of human prostatic smooth muscle cells. MATERIALS AND METHODS Primary cultures of human prostatic smooth muscle cells were obtained from 7 patients with bladder outlet obstruction caused by benign prostatic enlargement. A cell proliferation study was performed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay method to examine the effects of different concentrations of ouabain and various inhibitors. Western blot analysis was done to determine mitogen activated protein kinase (MAPK) activation. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling reaction method and caspase-3 activity assay were also performed to examine the apoptotic mechanism. RESULTS Ouabain exhibited a modest but significant proliferative effect in nanomolar concentrations; whereas it induced cell apoptosis at higher concentrations. Ouabain caused rapid activation of p42/44 MAPKs. The proliferative effect of ouabain was completely flattened by W-7 and MAPK kinase (MEK) inhibitor, suggesting the requirement of Ca(2+) mobilization and the involvement of the MEK-p42/44 MAPK cascade. The cytotoxic effect by ouabain was defined as apoptosis and necrosis using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling reaction technique and lactate dehydrogenase release assay, respectively. In addition, ouabain induced profound caspase-3 activity in the cytotoxic concentrations and DEVD-CHO reversed the cytotoxic action to ouabain, demonstrating the involvement of caspase-3 activation in the cytotoxic action. CONCLUSIONS Ouabain at different concentrations caused dual effects on proliferation and apoptosis in human prostatic smooth muscle cells. At low concentrations ouabain promoted cell proliferation via a Ca(2+) dependent mechanism and activation of the MEK-p42/44 MAPK pathway; whereas it induced cell apoptosis via the activation of caspase-3 activity at higher concentrations.

131I-6β-Iodomethyl-19-Norcholesterol SPECT/CT for Primary Aldosteronism Patients with Inconclusive Adrenal Venous Sampling and CT Results

The 2 main causes of primary aldosteronism (PA) are aldosterone-producing adenoma (APA) and idiopathic adrenal hyperplasia (IAH). Dexamethasone-suppression 131I-6β-iodomethyl-19-norcholesterol (NP-59) adrenal scintigraphy can assess the functioning of the adrenal cortex. This study evaluated the diagnostic usefulness of NP-59 SPECT/CT in differentiating APA from IAH and in predicting postadrenalectomy clinical outcome for PA patients who had inconclusive adrenal venous sampling (AVS) and CT results. Methods: We retrospectively reviewed the 31 adrenal lesions of 27 patients (age range, 33–71 y; mean age ± SD, 50.4 ± 10.9 y) who had been clinically confirmed (by saline infusion and captopril tests) to have PA, had inconclusive CT and AVS test results, and had undergone NP-59 imaging before adrenalectomy. The accuracy of NP-59 imaging was determined by comparison with histopathologic findings. Results: NP-59 SPECT/CT gave us 18 true-positive, 3 false-positive, 6 true-negative, and 4 false-negative results. Compared with planar imaging, SPECT/CT significantly improved diagnostic accuracy and prognostic predicting ability (P = 0.0390 and P = 0.0141, respectively). The NP-59 results were negative for 7 of the 23 patients with unilateral adrenal lesions, and none of these 7 patients had shown postsurgical clinical improvement. Conclusion: NP-59 SPECT/CT is an effective imaging tool for differentiating APA from IAH in PA patients whose CT and AVS results are inconclusive. Our results suggest that patients with presurgically negative NP-59 results should be treated medically and that noninvasive NP-59 SPECT/CT may be suited for use as the first lateralization modality after CT in patients with clinically confirmed PA.

Association of Kidney Function With Residual Hypertension After Treatment of Aldosterone-Producing Adenoma

BACKGROUND Autonomous secretion of aldosterone in patients with primary aldosteronism increases glomerular filtration rate and causes kidney damage. The influence of a mild decrease in kidney function on residual hypertension after adrenalectomy is unexplored. STUDY DESIGN Nonconcurrent prospective study. SETTING & PARTICIPANTS The study was based on the Taiwan Primary Aldosteronism Investigation (TAIPAI) database. 150 patients (61 men; overall mean age, 47.2 +/- 11.6 years) with a diagnosis of aldosterone-producing adenoma had undergone unilateral adrenalectomy at National Taiwan University Hospital from July 1999 to January 2007. PREDICTOR Presurgery estimated glomerular filtration rate (eGFR). OUTCOMES & MEASUREMENTS Residual hypertension after adrenalectomy, defined either as less than 75% of recorded blood pressure measurements with systolic blood pressure less than 140 mm Hg and diastolic blood pressure less than 90 mm Hg or requiring antihypertensive medications during the first year after surgery. RESULTS Before surgery, 27 (18%), 72 (48%), and 51 (34%) patients had moderately to severely decreased (<60 mL/min/1.73 m(2)), mildly decreased (60 <or= eGFR < 90 mL/min/1.73 m(2)), or nondecreased eGFR (>or=90 mL/min/1.73 m(2)), respectively. After surgery, 16 (59.3%), 29 (40.3%), and 10 (19.3%) patients in each category had postsurgery residual hypertension. Compared with patients without decreased eGFR before surgery, adjusted odds ratios for postsurgery residual hypertension were 2.7 (95% confidence interval, 1.03 to 7.0; P = 0.04) and 2.8 (95% confidence interval, 1.05 to 9.3) for mildly and moderately to severely decreased eGFR, respectively. LIMITATIONS Arbitrary definition for residual hypertension. CONCLUSIONS Two-thirds of patients with aldosterone-producing adenoma were cured of hypertension by means of unilateral adrenalectomy. Kidney function impairment, even mild, appears to be associated with a high incidence of postsurgery residual hypertension.

Expanding the donor pool: use of renal transplants from non-heart-beating donors supported with extracorporeal membrane oxygenation

Abstract:  In response to organ shortage, we used the renal grafts from non‐heart‐beating donors (NHBDs). Extracorporeal membrane oxygenation (ECMO) was used to maintain NHBDs before organ procurement. We compared the results of renal transplantation from different donors, including heart‐beating donors (HBDs), living‐related donors (LDs), and NHBDs supported with ECMO. From February 1998 to June 2003, we recruited 219 patients receiving renal transplantation at National Taiwan University Hospital. Among them, 31 received kidneys from NHBDs supported with ECMO, 120 from HBDs, and 68 from LDs. Multiple organ transplant recipients were not included in this study. We compared the graft survival, serum creatinine levels, and estimated glomerular filtration rates of the three groups. The rate of delayed graft function was higher in NHBD recipients (41.9%) than in HBD recipients (27.0%) and LD recipients (10.9%) (p = 0.003). In the NHBD group, the recipients of grafts with delayed function had significantly longer ECMO runs (63.1 ± 3.0 min) than those without delayed function (53.7 ± 2.5 min) (p = 0.024). Estimated glomerular filtration rate (p = 0.472) and mean serum creatinine level (p = 0.286) were not significantly different between the three groups using a longitudinal approach. The 5‐yr graft survival rates for NHBD (88.4%, 95% CI: 0.680–0.962), HBD (83.2%, 95% CI: 0.728–0.899), and LD transplant recipients (89.3%, 95% CI: 0.619–0.974) were not significantly different (p = 0.239). The 5‐yr patient survival rates for NHBD, HBD, and LD transplant recipients were 100, 93.0 (95% CI: 0.859–0.966) and 100% respectively. The long‐term allograft survival and function of kidneys from NHBDs supported by ECMO, HBD, and LD did not differ significantly. Long ECMO running time tended to delay graft function.

Kidney impairment in primary aldosteronism

BACKGROUND Kidney impairment is noted in primary aldosteronism (PA), and probably initiated by glomerular hyperfiltration. METHODS A prospectively defined survey was conducted on 602 patients who were suspected of PA in the multiple-center Taiwan Primary Aldosteronism Investigation (TAIPAI) database. Estimated glomerular filtration rate (eGFR) was calculated and followed up at 1 yr after treatment. RESULTS The diagnosis of PA was confirmed in 330 patients. Among them 17% of these patients had kidney impairment (eGFR<60 ml/min/1.73 m²). Patients with PA had a higher prevalence of estimated hyperfiltration than those with essential hypertension (EH) (14.5% vs. 7.0%, p=0.005). The eGFR independently predicted PA (OR, 1.017) in the propensity-adjusted multivariate logistic model. In PA, plasma renin activity and lower serum potassium (p=0.018) was correlated with kidney impairment (p=0.001), while this relationship was not significant in patients with EH. Either unilateral adrenalectomy or treatment of spironolactone for PA patients caused a decrease of eGFR (p<0.001). Pre-operative hypokalemia (p=0.013) and the long latency of hypertension (p=0.016) could enhance the significant decrease of eGFR after adrenalectomy. CONCLUSIONS Patients with aldosteronism had relative estimated hyperfiltration than patients with EH. Calculation of eGFR may increase the specificity in identifying patients with PA. Our findings demonstrate the correlation of serum potassium and renin with estimated hyperfiltration in PA and their relationship to kidney damage. These results provide a high priority for future renal protective strategies and methods for the early diagnosis and prompt treatment of PA.

Adrenalectomy improves increased carotid intima-media thickness and arterial stiffness in patients with aldosterone producing adenoma.

CONTEXT Primary aldosteronism (PA) is the most frequent cause of secondary hypertension, and is associated with more prominent vascular stiffness and atherosclerosis. However, the effect of adrenalectomy on reversibility of vascular damage is unclear. OBJECTIVE Our objective was to investigate the vascular changes and possibility of reversibility after adrenalectomy in PA patients. METHODS We prospectively analyzed 20 patients with aldosterone producing adenoma (APA) that received adrenalectomy from October 2006 to December 2008 and 21 patients with essential hypertension (EH) were enrolled as the control group. Carotid intima media thickness (CIMT) measurement by B-mode ultrasound of the right common carotid arteries and pulse wave velocity (PWV) measurement including brachial-ankle PWV (baPWV) and heart-ankle PWV (haPWV) were performed in both groups. The follow-up measurements were performed one-year after adrenalectomy in APA group. RESULTS APA patients had significantly higher diastolic blood pressure, plasma aldosterone concentration (PAC) and aldosterone-renin ratio (ARR), but lower serum potassium level and plasma renin activity (PRA) than EH patients. APA patients had significantly higher CIMT (0.64±0.13 vs. 0.53±0.10 mm, p=0.006), higher baPWV (1589±296 vs. 1405±187 cm/s, p=0.024) and haPWV (1095±150 vs. 987±114 cm/s, p=0.013) comparing with EH patients. One-year after adrenalectomy, CIMT reduced significantly from 0.64±0.13 mm to 0.59±0.14 mm (p=0.014), and baPWV and haPWV also showed significant reduction (baPWV, 1589±296 to 1463±188 cm/s, p=0.035; haPWV, 1095±150 to 1017±109 cm/s, p=0.019). CONCLUSION APA patients have higher degree of early atherosclerosis and vascular stiffness. Adrenalectomy not only corrects the high blood pressure and biochemical parameters but also reverse adverse vascular change in APA patients.

Bilateral aldosterone-producing adenomas: differentiation from bilateral adrenal hyperplasia

BACKGROUND Primary aldosteronism (PA) is a common curable disease of secondary hypertension. Most such patients have either idiopathic bilateral adrenal hyperplasia (BAH) or unilateral aldosterone-producing adenoma (APA). Bilateral APAs are reportedly extremely rare. AIM To compare the distinctive characteristics, clinical course, and outcomes of bilateral APA vs. BAH. DESIGN Retrospective record review. METHODS From July 1994 to Jan 2007, 190 patients diagnosed with PA underwent surgical intervention at our hospital. Bilateral APA was diagnosed in 7/164 patients with histologically-proven APA. Twenty-one patients diagnosed as BAH, and 21 randomly selected of unilateral APA patients, matched by age and sex served as controls. RESULTS Patients with bilateral APA had similar blood pressure, arterial blood gas analysis, spot urinary potassium to creatinine ratio and clinical symptoms to those with BAH, but lower serum potassium levels (p = 0.027), lower plasma renin activity (p = 0.037), and higher plasma aldosterone concentrations (p = 0.029). Aldosterone-renin ratio (ARR) after administration of 50 mg captopril was higher in bilateral APA than in BAH patients (p = 0.023), but not different between unilateral APA and BAH (p = 0.218). A cut-off of ARR >100 ng/dl per ng/ml/h and plasma aldosterone >20 ng/dl after captopril significantly differentiated bilateral APA from BAH. Bilateral subtotal adrenalectomy normalized blood pressure and biochemistry in all patients with bilateral APA. DISCUSSION Bilateral APA, presenting simultaneously or sequentially, may not be a rare disease, accounting for 4.3% of APA in this sample. The clinical presentations of bilateral functional adenoma are not different from BAH, but patients with low serum potassium and ARR >100 after captopril should be carefully evaluated for bilateral adenoma.

Characterization of α1-adrenoceptor subtypes in tension response of human prostate to electrical field stimulation

1 The effects of various α1‐adrenoceptor antagonists and nifedipine on tension responses of human prostate to electrical field stimulation were evaluated in this study. 2 Prazosin (3 × 10−10 to 10−8M) and 5‐methyl‐urapidil (10−9 to 3 × 10−8 M) blocked concentration‐dependently the tension responses to electrical field stimulation and completely abolished them in the maximal concentrations (10−8 M and 3 × 10−8 M, respectively); in contrast, chloroethylclonidine (CEC), in the maximal concentration of 100 μM, blocked these effects by only 50%. 3 The contractile responses of rat vas deferens and spleen to exogenously‐applied α1radrenoceptor agonists were competitively inhibited by prazosin and 5‐methyl‐urapidil; in addition, the pA2 values were calculated and the relative potencies with reference to prazosin were obtained. The relative potency of 5‐methyl‐urapidil in human prostate (0.105) was close to that in rat vas deferens (0.257), which contains primarily putative α1A‐adrenoceptors. However, it was much more than that in rat spleen (0.011), which contains primarily putative α1B‐adrenoceptors. 4 Nifedipine (10−8 to 10−6 M) inhibited concentration‐dependently the contractile responses to electrical field stimulation in human prostate; in addition, the inhibition percentages were similar to those to exogenously‐applied noradrenaline in rat vas deferens. In contrast, CEC (10 μM), which almost flattened the concentration‐response curve of the rat spleen to phenylephrine, only partially inhibited (by 33.1%) the nerve‐mediated contraction of human prostate. 5 The involvement of prejunctional α2‐adrenoceptors situated on the sympathetic nerve terminals of human prostate was also examined. Clonidine (3 × 10−9 to 3 × 10−7 M) blocked concentration‐dependently the contractile response to electrical field stimulation of human prostate and this inhibitory effect was reversed by yohimbine (10−7 M). Additionally, the inhibitory effect of CEC (3 × 10−6 to 3 × 10−4 M) to the nerve‐mediated contraction was also partially reversed by yohimbine (10−7M). 6 It is suggested that the putative α1A‐adrenoceptors in human prostate may be functionally confined to the synaptic region whereas only minor populations of the putative α1B‐ and/or αlc‐adrenoceptors exist in this region.

Primary Aldosteronism: Diagnostic Accuracy of the Losartan and Captopril Tests

BACKGROUND To assess whether angiotensin-II receptor blockers (ARBs) offer any additional advantage in confirming the diagnosis of primary aldosteronism (PA) and their use in the differentiation of PA subtypes. METHODS A prospective, cohort, head-to-head study was conducted between July 2003 and July 2006. A total of 135 patients received captopril and losartan tests to confirm the diagnosis of PA in the TAIPAI (Taiwan Primary Aldosteronism Investigation) intervention. RESULTS In total, 71 patients were diagnosed with PA. The area under the receiver-operating characteristic (ROC) curve of the postcaptopril plasma aldosterone concentration (PAC) was significantly less than that of the postlosartan PAC (0.744 vs. 0.829, P = 0.038). Using an aldosterone-renin ratio (ARR, ng/dl per ng/ml/h) >35 with a PAC >10 ng/dl, the specificity was 89.1% vs. 93.8% and the sensitivity was 66.2% vs. 84.5 % for the captopril test vs. the losartan test, respectively. With respect to the losartan test, the accuracy was 88.9%, the agreement was good (k = 0.778), and there was no disagreement with the McNemar test (P = 0.118). Losartan had the advantage of a better negative predictive value to exclude PA when patients were referred with a serum potassium (SK) level <3.8 mmol/l. When a postlosartan ARR >60 was the cutoff value, the positive predictive value was 82% with a negative predictive value of 57% in distinguishing aldosterone-producing adenomas (APAs) from idiopathic hyperaldosteronism (IHA). CONCLUSIONS The postlosartan ARR and PAC were shown to have better accuracy for the diagnosis of PA than the captopril test. With a postlosartan ARR >60, APAs can be adequately differentiated from IHA.

Washout gradient in dynamic contrast-enhanced MRI is associated with tumor aggressiveness of prostate cancer.

To investigate the associations between dynamic contrast‐enhanced magnetic resonance imaging (DCE MRI) parameters and the Gleason score (GS) for prostate cancer (PCA) with localization information provided by concurrent apparent diffusion coefficient (ADC) maps.