Time-course changes of nLDL-induced erectile dysfunction.

Hyperlipidemia is an important risk factor for atherosclerosis and is frequently seen in patients with erectile dysfunction (ED). This study was designed to evaluate whether the acute effect of native low-density lipoprotein (nLDL) on intracavernosal pressure (ICP) is reversible and related to plasma asymmetrical dimethylarginine (ADMA), endogenous inhibition of endothelial nitric oxide synthase (eNOS) levels and eNOS expression in cavernous tissues. Hyperlipidemia was induced by a single dose of intravenous 4 mg kg-1 nLDL. Experiments were performed 72 h (72H), 2 weeks (2W) and 8 weeks (8W) after nLDL injection. Endothelium-dependent relaxations, the ratio of ICP to mean arterial pressure (MAP; ICP/MAP), plasma ADMA levels and eNOS mRNA and protein levels were evaluated. The ICP/MAP ratio decreased in both the 2W and 8W groups. Endothelium-dependent relaxation responses to acetylcholine in the rat thoracic aorta were damaged in the 8W group. Plasma ADMA levels increased in the 8W group. mRNA expression of eNOS decreased in a time-dependent manner, whereas the protein expression increased. These results suggest that acute nLDL injection-induced impairments in erectile functions during an 8-week period are irreversible and might be related to an increase in ADMA levels and changes in the regulation of the eNOS/NO pathway.

Hepatic progenitor cell inhibition during embryonic period with high dose verapamil; liable joint to the cancer therapy.

Cancer stem cells (CSCs) have been observed to share certain characteristics with normal stem cells. It was an important argument for cancer therapy and a successful progenitor inhibition could show us targeted cell type for a novel strategy. In this study, we aimed to constitute an inhibition in different stages of hepatic stem/progenitor cells (HPCs) with verapamil. Expression patterns of alpha-fetoprotein (AFP), c-kit (CD117) and p-glycoprotein were investigated in developing mouse on the embryonic day (E) 15, E18 and E21 to characterize early and late stages of HPCs. Proliferation inhibition with 5-Bromo-2-Deoxyuridin (BrdU) incorporation and maturation inhibition with PAS staining results were supported by morphometrical analysis during these periods. AFP, c-kit and p-glycoprotein immunoreactivity increased especially in E15 but decreased in E18 and E21 of the control groups during embryonic development. Verapamil treatment effected particularly E15 cells and immunoexpression of HPCs significantly decreased. Proliferation inhibition was observed in all embryonic days of mouse with verapamil and this drug inhibited not only maturation of HPCs in E18 and E21 embryos, but also decreased HPC number in the same embryonic period. According to our results, we estimated that similar to the early and late progenitor stages of HPCs, CSCc can also be in different stages in a heterogenic tumour bulk and the difficulty of CSC inhibition could be the main mechanism of tumour relapses. In this study, HPCs inhibition by verapamil in E15 was not observed in E18 and E21. As similar, CSCs treatments targeting different stages may be impotent to cells in tumour initiating cell stage. We can speculate that ineffectiveness of CSC-specific therapies may be attributed to the highly selective specificity of the treatment (Fig. 6, Ref. 28).

The role of calcium entry on the relaxation response of rho-kinase inhibitor in rabbit renal artery.

This study was performed to clarify the role of extracellular and intracellular Ca2+ on rho-kinase enzyme inhibition-induced relaxation in rabbit renal arteries. The response to rho-kinase inhibitor (Y-27632) was studied in isolated renal artery segments precontracted with phenylephrine in the presence of voltage-gated calcium channel blocker nifedipine and in the absence of intracellular or extracellular Ca2+. Cumulative addition of rho-kinase inhibitor Y-27632 (10-8-10-5 M) produced a concentration-dependent relaxation in renal artery rings precontracted with phenylephrine. Preincubation with nifedipine (1µM) resulted in a significant increase in relaxation response to rho-kinase inhibitor Y-27632 compared with preincubation with DMSO; the solvent of nifedipine. The maximal relaxation to Y-27632 in renal arteries precontracted with phenylephrine was significantly increased in the Ca-free Krebs containing 100 µmol/l ethylene glycol tetraacetic acid (EGTA) but after depletion of intracellular stores with 20 mmol/l caffeine and 1mmol/l EGTA in Ca2+ free Krebs there was no significant difference between the relaxation to Y-27632 from control response in 2.5 mmol/l Ca2+ Krebs in the renal artery. These results suggest the involvement of extracellular Ca and L-type voltage-operated Ca2+ channels in phenylephrine-induced rho-kinase activation (Fig. 3, Ref. 20).

Doxorubicin induced nephrotoxicity: protective effect of nicotinamide.

Introduction. Nephrotoxicity is one of the important side effects of anthracycline antibiotics. The aim of this study was to investigate the effects of nicotinamide (NAD), an antioxidant agent, against nephrotoxicity induced by doxorubicin (DXR). Methods. The rats were divided into control, NAD alone, doxorubicin (20 mg/kg, i.p.) and DXR plus NAD (200 mg/kg, i.p.) groups. At the end of the 10th day, kidney tissues were removed for light microscopy and analysis. The level of tissues' catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx), inducible nitric oxide (iNOS) and endothelial nitric oxide (eNOS) activities were determined. Results. The activities of CAT, GPx, and GSH were decreased, and Po was increased in renal tissue of doxorubicin group compared with other groups. The tissue of the doxorubicin group showed some histopathological changes such as glomerular vacuolization and degeneration, adhesion to Bowman's capsule and thickening and untidiness of tubular and glomerular capillary basement membranes. Histopathological examination showed that NAD prevented partly DXR-induced tubular and glomerular damage. Conclusions. Pretreatment with NAD protected renal tissues against DXR-induced nephrotoxicity. Preventive effects of NAD on these renal lesions may be via its antioxidant and anti-inflammatory action.

Evaluation of vascular smooth muscle and corpus cavernosum on hypercholesterolemia. Is resveratrol promising on erectile dysfunction?

The aim of this study is to evaluate the effects of hypercholesterolemia in thoracic aorta (TA), mesenteric artery (MA), renal artery (RA), and corpus cavernosum (CC) isolated from cholesterol-fed rabbits. For determination of the maximum detrimental effect, vasorelaxation and vasoconstriction results of arteries and CC have been compared. Animals were fed with a diet that contained 2% w/w cholesterol and 2% w/w high cholesterol plus resveratrol (4 mg kg(-1) per day) for 6-week duration. Total cholesterol levels in the plasma were measured. Vascular and endothelial functions in RA, TA, MA, and CC were assessed by isolated tissue bath with cumulative doses of acetylcholine and sodium nitroprusside. The statistical significance of differences of groups was analyzed by means of one-way ANOVA or Student's t-test. P-values <0.05 were considered significant. There have been no significant changes on plasma total cholesterol levels between cholesterol and cholesterol + resveratrol-treated groups. Vasorelaxation responses to acetylcholine in resveratrol-treated group showed significant changes when compared with hypercholesterolemic group. No statistically significant differences were seen between non-receptor-mediated vasorelaxation responses between the three groups. Resveratrol might be an effective treatment in the prevention of atherosclerotic changes in arteries and CC. The initial effects of hypercholesterolemia on erectile dysfunction and endothelial dysfunction may be precluded with resveratrol. This protective effect may also ensure the prevention of coronary arterial diseases and renovascular diseases in hypercholesterolemic patients.

Vasorelaxant effect of iloprost on isolated human internal mammary artery.

In this study, vasodilator effect of iloprost on KCl-induced contraction in human internal mammary artery (IMA) was studied and compared with other vasodilators papaverin and diltiazem. Ring segments of IMA were studied in organ baths for measurement of isometric tension. After the tissues has reached their baseline tension, precontraction was induced by 100 mm KCl and cumulative concentration-relaxation was measured by the application of iloprost (10(-9)-10(-6) m), papaverine (10(-5)-10(-4) m), diltiazem (10(-9)-10(-4) m) or ethanol; a solvent for iloprost; alone. The maximal relaxation of IMA segments to iloprost was 13.5 +/- 2.2%. Iloprost caused significantly limited relaxation when compared with papaverin (106.0 +/- 2.9%) and diltiazem (93.6 +/- 2.5%) (P < 0.001). Papaverin produced the greatest maximal relaxation to KCl-induced contraction of IMA. The potency of iloprost (-log EC(50) = 6.59 +/- 0.19) was significantly higher than those of papaverine (-log EC(50) = 4.21 +/- 0.11) and diltiazem (-log EC(50) = 5.63 +/- 0.06) (P < 0.001). In addition, -log EC(50) of diltiazem was significantly greater than papaverin (P < 0.001). Iloprost appears to be more potent than those of papaverine and diltiazem but it was inefficient in maximal inhibition on KCl-induced contraction. Iloprost may have little benefit in KCl-related vasoconstriction on human IMA segments.