Ruthenium (II)/allopurinol complex inhibits breast cancer progression via multiple targets

Metal complexes based on ruthenium have established excellent activity with less toxicity and great selectivity for tumor cells. This study aims to assess the anticancer potential of ruthenium(II)/allopurinol complexes called [RuCl₂(allo)₂(PPh₃)₂] (1) and [RuCl₂(allo)₂(dppb)] (2), where allo means allopurinol, PPh₃ is triphenylphosphine and dppb, 1,4-bis(diphenylphosphino)butane. The complexes were synthesized and characterized by elemental analysis, IR, UV-Vis and NMR spectroscopies, cyclic voltammetry, molar conductance measurements, as well as the X-ray crystallographic analysis of complex 2. The antitumor effects of compounds were determined by cytotoxic activity and cellular and molecular responses to cell death mechanisms. Complex 2 showed good antitumor profile prospects because in addition to its cytotoxicity, it causes cell cycle arrest, induction of DNA damage, morphological and biochemical alterations in the cells. Moreover, complex 2 induces cell death by p53-mediated apoptosis, caspase activation, increased Beclin-1 levels and decreased ROS levels. Therefore, complex 2 can be considered a suitable compound in antitumor treatment due to its cytotoxic mechanism.

Atorvastatin and sildenafil decrease vascular TGF-β levels and MMP-2 activity and ameliorate arterial remodeling in a model of renovascular hypertension

Imbalanced matrix metalloproteinase (MMP)-2 activity and transforming growth factor expression (TGF-β) are involved in vascular remodeling of hypertension. Atorvastatin and sildenafil exert antioxidant and pleiotropic effects that may result in cardiovascular protection. We hypothesized that atorvastatin and sildenafil alone or in association exert antiproliferative effects by down-regulating MMP-2 and TGF-β, thus reducing the vascular hypertrophy induced by two kidney, one clip (2K1C) hypertension.

Sham and 2K1C rats were treated with oral atorvastatin 50 mg/kg, sildenafil 45 mg/kg, or both, daily for 8 weeks. Blood pressure was monitored weekly. Morphologic changes in the aortas were studied. TGF-β levels were determined by immunofluorescence. MMP-2 activity and expression were determined by in situ zymography, gel zymography, Western blotting, and immunofluorescence. The effects of both drugs on proliferative responses of aortic smooth muscle cells to PDGF and on on MMP-2 activity in vitro were determined. Atorvastatin, sildenafil, or both drugs exerted antiproliferative effects in vitro. All treatments attenuated 2K1C-induced hypertension and prevented the increases in the aortic cross-sectional area and media/lumen ratio in 2K1C rats. Aortas from 2K1C rats showed higher collagen deposition, TGF-β levels and MMP-2 activity and expression when compared with Sham-operated animals. Treatment with atorvastatin and/or sildenafil was associated with attenuation of 2K1C hypertension-induced increases in these pro-fibrotic factors. However, these drugs had no in vitro effects on hr-MMP-2 activity.

Atorvastatin and sildenafil was associated with decreased vascular TGF-β levels and MMP-2 activity in renovascular hypertensive rats, thus ameliorating the vascular remodeling. These novel pleiotropic effects of both drugs may translate into protective effects in patients.

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Atorvastatin and sildenafil exert antioxidant and other pleotropic effects.

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Imbalanced MMP-2 activity and TGF-β expression promote vascular remodeling in hypertension.

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Atorvastatin and sildenafil exerted antiproliferative effects in vitro.

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Both drugs prevented hypertension-induced increases pro-fibrotic factors.

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These additional pleiotropic effects may translate into protective effects in patients.

β1-Adrenergic blockers exert antioxidant effects, reduce matrix metalloproteinase activity, and improve renovascular hypertension-induced cardiac hypertrophy

Hypertension induces left-ventricular hypertrophy (LVH) by mechanisms involving oxidative stress and unbalanced cardiac matrix metalloproteinase (MMP) activity. We hypothesized that β1-adrenergic receptor blockers with antioxidant properties (nebivolol) could reverse hypertension-induced LVH more effectively than conventional β1-blockers (metoprolol) when used at doses that exert similar antihypertensive effects. Two-kidney one-clip (2K1C) hypertension was induced in male Wistar rats. Six weeks after surgery, hypertensive and sham rats were treated with nebivolol (10 mg kg(-1)day(-1)) or metoprolol (20 mg kg(-1)day(-1)) for 4 weeks. Systolic blood pressure was monitored weekly by tail-cuff plethysmography. LV structural changes and fibrosis were studied in hematoxylin/eosin- and picrosirius-stained sections, respectively. Cardiac MMP levels and activity were determined by in situ zymography, gel zymography, and immunofluorescence. Dihydroethidium and lucigenin-derived chemiluminescence assays were used to assess cardiac reactive oxygen species (ROS) production. Nitrotyrosine levels were determined in LV samples by immunohistochemistry and green fluorescence and were evaluated using the ImageJ software. Cardiac protein kinase B/Akt (AKT) phosphorylation state was assessed by Western blot. Both β-blockers exerted similar antihypertensive effects and attenuated hypertension-induced cardiac remodeling. Both drugs reduced myocyte hypertrophy and collagen deposition in 2K1C rats. These effects were associated with lower cardiac ROS and nitrotyrosine levels and attenuation of hypertension-induced increases in cardiac MMP-2 levels and in situ gelatinolytic activity after treatment with both β-blockers. Whereas hypertension increased AKT phosphorylation, no effects were found with β-blockers. In conclusion, we found evidence that two β1-blockers with different properties attenuate hypertension-induced LV hypertrophy and cardiac collagen deposition in association with significant cardiac antioxidant effects and MMP-2 downregulation, thus suggesting a critical role for β1-adrenergic receptors in mediating those effects. Nebivolol is not superior to metoprolol, at least with respect to their capacity to reverse hypertension-induced LVH.

Nebivolol attenuates prooxidant and profibrotic mechanisms involving TGF-β and MMPs, and decreases vascular remodeling in renovascular hypertension

Nebivolol and metoprolol are β1-adrenergic receptor blockers with different properties. We hypothesized that nebivolol, but not metoprolol, could attenuate prooxidant and profibrotic mechanisms of hypertension and therefore protect against the vascular remodeling associated with hypertension. Hypertension was induced in male Wistar rats by clipping the left renal artery. Six weeks after surgery, hypertensive and sham rats were treated with nebivolol (10 mg kg(-1) day(-1)) or metoprolol (20 mg kg(-1) day(-1)) for 4 weeks. Systolic blood pressure was monitored weekly. Morphologic changes in the aortic wall were studied in hematoxylin/eosin and picrosirius red sections. Aortic NAD(P)H activity and superoxide production were evaluated by luminescence and dihydroethidium, respectively, and TBARS levels were measured in plasma. Aortic nitrotyrosine staining was evaluated to assess peroxynitrite formation. TGF-β levels and p-ERK 1/2 expression were determined by immunofluorescence and Western blotting, respectively. Matrix metalloproteinase (MMP) activity and expression were determined by in situ zymography, gel zymography, Western blotting, and immunofluorescence, and TIMP-1 was assessed by immunohistochemistry. Both β1-receptor antagonists exerted very similar antihypertensive effects. However, while metoprolol had no significant effects, nebivolol significantly attenuated vascular remodeling and collagen deposition associated with hypertension. Moreover, nebivolol, but not metoprolol, attenuated hypertension-induced increases in aortic NAD(P)H oxidase activity, superoxide production, TBARS concentrations, nitrotyrosine levels, TGF-β upregulation, and MMP-2 and -9 expression/activity. No effects on p-ERK 1/2 and TIMP-1 expression were found. These results show for the first time that nebivolol, but not metoprolol, attenuates prooxidant and profibrotic mechanisms involving TGF-β and MMP-2 and MMP-9, which promote vascular remodeling in hypertension.

Abstract 301: Nebivolol Attenuates Prooxidant and Profibrotic Mechanisms and Decreases Vascular Remodeling in Renovascular Hypertension

Nebivolol and metoprolol are β1-adrenergic receptor blockers with different properties. We hypothesized that nebivolol, but not metoprolol, could attenuate prooxidant and profibrotic mechanisms of hypertension vascular remodeling. Hypertension was induced in male Wistar rats by clipping the left renal artery. Six weeks after surgery, hypertensive and sham rats were treated with nebivolol (Nebi 10 mg/kg/day), metoprolol (Meto 20 mg/kg/day) or vehicle for four weeks. Systolic blood pressure was monitored weekly. Morphologic changes in the aortic wall were studied in picrosirius red sections. Aortic NAD(P)H activity was evaluated by luminescence. Nitrotyrosine staining was evaluated to assess peroxynitrite formation by immunohistochemistry. TGF-β and matrix metalloproteinase-9 (MMP-9) levels were determined by immunofluorescence, and p-ERK 1/2 expression by western blotting. Both β1-receptor antagonists exerted very similar antihypertensive effects (156 ± 8 mmHg and 151 ± 9 mmHg, respectively, versus 206 ± 7 mmHg in hypertensive controls; both P<0.05). However, while metoprolol had no significant effects, nebivolol significantly (all P<0.05) attenuated vascular collagen surface (237944 ± 59567, 69784 ± 17686, 183215 ± 30338 μm2, respectively, in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups), attenuated hypertension-induced increases in aortic NAD(P)H oxidase activity (253887 ± 13712, 143765 ± 15642, and 232465 ± 14352 AU, respectively in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups), in nitrotyrosine levels (166.3 ± 2.9, 145.3 ± 1.5, 172.1 ± 7.3 AU, respectively, in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups), in TGF-β upregulation (7.2 ± 0.12, 6.5 ± 0.03, 7.0 ± 0.3 AU, respectively, in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups) and in MMP-9 levels (18.27 ± 0.8, 12.73 ± 0.4, 15.76 ± 1.4 AU, respectively in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups). No effects on p-ERK 1/2 expression were found with both drugs (P>0.05) (1.0 ± 0.16, 0.92 ± 0.15, 0.87 ± 0.37 AU, respectively, in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups). These results show for the first time that nebivolol, but not metoprolol, attenuates prooxidant and profibrotic mechanisms involving TGF-β and MMP-9, which promote vascular remodeling in hypertension.

Abstract 393: Chronic Nebivolol Treatment Attenuates MMP Activity and Oxidative Stress and Improves Renovascular Hypertension-induced Cardiac Hypertrophy

Nebivolol (Nebi) is the most selective cardiac β1-adrenergic receptor blocker and exerts antioxidant effects. Reactive oxygen species (ROS) enhance cardiac matrix metalloproteinase activity (MMPs) and contribute to hypertension-induced left ventricular hypertrophy (LVH). However, it is uncertain whether Nebi decreases MMP-2 levels and cardiac remodeling associated with hypertension as a result of its antioxidant properties. Hypertension was induced by clipping the left renal artery (2K1C). Six weeks after surgery, hypertensive and sham rats were treated with Nebi, Metoprolol (Meto) or Vehicle (by gavage) for four weeks. Systolic blood pressure (SBP) was monitored weekly by tail-cuff plethysmography. LV structural changes were studied in hematoxylin/eosin sections. MMP levels and activity were determined by immunofluorescence and in situ zymography. ROS and nitrotyrosine levels were evaluated by dihydroethidium and immunohistochemistry, respectively. Similar reduction in SBP was found with both treatments (202±5 mmHg in 2K1C+Vehicle versus 161±19 and 162±18 mmHg in 2K1C Nebi or Meto groups, respectively; P<0.05). Both treatments reduced LV remodeling and ROS formation (P<0.05). Both drugs decreased nitrotyrosine levels (3.9±0.2, 2.3±0.3, and 2.4±0.3 arbitrary units, respectively in 2K1C+vehicle, 2K1C+Meto, and 2K1C+Nebi groups, respectively; P<0.05). Increased MMP-2 levels (16.0±2.0 versus 7.0±0.9 arbitrary units; P<0.05) and activity (8.0±0.4 versus 6.0±0.1 arbitrary units; P<0.05) were observed in the 2K1C+vehicle group when compared to the sham group. These alterations were normalized by both treatments (similar levels to those found in the sham group). No significant changes were observed in the sham groups. These findings suggest that different β-blockers exert important antioxidant effects that may underlie the lower LV MMP activity and cardiac remodeling in 2K1C hypertension.

Abstract 529: Atorvastatin and Sildenafil Reduce Vascular Remodeling and Oxidative Stress in 2K1C-hypertension

Atorvastatin (ATORVA) and sildenafil (SILD) exert beneficial effects on cardiovascular diseases through their pleiotropic effects. Hypertension-induced vascular hypertrophy is associated with oxidative stress and matrix metalloproteinase (MMP) up-regulation. We evaluated the effects of ATORVA and SILD on vascular changes induced by MMPs and on oxidative stress and MMP activity in 2 kidney-1 clip (2K1C) hypertension. Sham and 2K1C rats were treated with vehicle, ATORVA (50 mg/kg), SILD (45 mg/kg) or both for 8 weeks. ATORVA, SILD, or both drugs exerted antihypertensive effects (systolic blood pressure: 148±6, 156±2, and 138±4 mmHg, respectively, vs. 200±4 mmHg in 2K1C untreated rats; P<0.05). All treatments prevented the increases in the aortic cross-sectional area and media/lumen ratio in 2K1C rats (P<0.05). Aortas from 2K1C rats showed higher MMP-2 levels when compared with sham and all treatments attenuated 2K1C hypertension-induced increases in MMP-2 levels (both P<0.05). Increased gelatinolytic activity (20.6±0.9 vs. 13.9±1.2 A.U.; arbitrary units) co-localized with upregulated aortic MMP-2 expression (8.1±0.3 vs. 5.4±0.4 A.U.) in 2K1C vs. control rats. ATORVA, SILD, or both drugs lowered gelatinolytic activity to 14.6±0.5, 14.6±1.0 and 14.5±0.8 A.U. and lowered the aortic MMP-2 expression to 5.8±0.3, 5.9±0.5 and 5.5±0.5 A.U., respectively. However, these drugs had no in vitro effects on human recombinant MMP-2 activity (P>0.05). Hypertension induced oxidative stress assessed with dihydroethidium probe (7.9±1.2 vs. 16.5±1.5 A.U. in sham vs 2K1C), which was attenuated by ATORVA, SILD or both (9.9±0.3, 10.4±1.5 and 9.6±0.6 A.U., respectively). Plasma malondialdehyde levels paralleled dihydroethidium results. Treatment with ATORVA or SILD, or both, exert antihypertensive effects and prevents 2K1C hypertension-induced vascular remodeling and oxidative stress. These effects were associated with lower MMP-2 levels possibly resulting of antioxidants effects. Our results suggest that ATORVA and SILD may prevent the vascular alterations of hypertension.Supported by FAPESP, Cnpq.

Abstract 265: Chronic Treatment with Nebivolol Attenuates the Vascular Changes in the 2-Kidney, 1-Clip Model of Renovascular Hypertension

Nebivolol (Nebi) is a β-1 receptor antagonist with vasodilator and antioxidant properties. Matrix metalloproteinases (MMPs) are enzymes involved in cardiovascular remodeling, and MMP upregulation has been associated with increased reactive oxygen species (ROS). Because vascular remodeling is associated with increased ROS and MMPs, it is possible that Nebi reverses the increased MMP levels and vascular remodeling associated with 2K-1C hypertension through its antioxidant activity. Hypertension was induced in male Wistar rats by clipping the left renal artery. Six weeks after surgery, hypertensive and sham rats were treated with Nebi (10 mg/kg/day), metoprolol (Meto; 20 mg/kg/day) or vehicle for four weeks. Systolic blood pressure (SBP) was monitored weekly by tail-cuff plethysmography. Structural changes of the aortic wall were studied in hematoxylin/eosin sections. MMPs levels and activity were determined by zymography and in situ zymography. NADPH oxidase activity and ROS production were evaluated by luminescence and dihydroethidium. Similar reductions in SBP were found with both Meto or Nebi treatments (156 ± 8 mmHg and 151 ± 9 mmHg, respectively, versus 206 ± 7 mmHg in hypertensive controls; both P<0.05). However, only Nebi (all P<0.05) reversed aortic hypertrophy (aortic cross sectional area x 10 4 = 89±5, 68±3, and 80±8 μm 2 , respectively, in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups), the increases in aortic MMP-2 levels (0.18±0.04, 0.07±0.02, and 0.12±0.06 arbitrary units; AU, respectively in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups), in aortic MMP activity (21071±700, 16217±818, and 18848±1396, respectively in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups), in aortic NADPH oxidase activity (253887±13712, 143765±15642, and 232465±14352 AU, respectively in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups) and in aortic ROS levels (8057±800, 4400±480, and 6230±1190 AU, respectively, in the 2K1C, 2K1C+Nebi, and 2K1C+Meto groups). No significant differences were found in the Sham groups. Our results suggest that lower vascular NADPH oxidase may explain, at least in part, the attenuation of oxidative stress and vascular remodeling associated with Nebi.

Specific matrix metalloproteinase 9 (MMP-9) haplotype affect the circulating MMP-9 levels in women with migraine

We investigated whether three relevant polymorphisms (C-1562T, microsatellite -90(CA)(14-24), and Q279R) in the MMP-9 gene, or MMP-9 haplotypes, are associated with migraine and affect MMP-9 and tissue inhibitor of MMPs (TIMP)-1 levels in patients with migraine. We studied 102 healthy women (controls) and 187 women with migraine (141 without aura - MWA, and 46 with aura - MA). Patients with MWA had higher plasma MMP-9 concentrations than patients with MA. Patients with MA had the highest TIMP-1 and lowest MMP-9/TIMP-1 ratios. The MMP-9 "C L Q" haplotype was associated with higher plasma MMP-9 concentrations in migraine patients.

Interaction among nitric oxide (NO)-related genes in migraine susceptibility

The pathogenic mechanisms involved in migraine are complex and not completely clarified. Because there is evidence for the involvement of nitric oxide (NO) in migraine pathophysiology, candidate gene approaches focusing on genes affecting the endothelial function have been studied including the genes encoding endothelial NO synthase (eNOS), inducible NO synthase (iNOS), and vascular endothelial growth factor (VEGF). However, investigations on gene-gene interactions are warranted to better elucidate the genetic basis of migraine. This study aimed at characterizing interactions among nine clinically relevant polymorphisms in eNOS (T(-786)C/rs2070744, the 27 bp VNTR in intron 4, the Glu298Asp/rs1799983, and two additional tagSNPs rs3918226 and rs743506), iNOS (C(-1026)A/rs2779249 and G2087A/rs2297518), and VEGF (C(-2578)A/rs699947 and G(-634)C/rs2010963) in migraine patients and control group. Genotypes were determined by real-time polymerase chain reaction using the Taqman(®) allele discrimination assays or PCR and fragment separation by electrophoresis in 99 healthy women without migraine (control group) and in 150 women with migraine divided into two groups: 107 with migraine without aura and 43 with aura. The multifactor dimensionality reduction method was used to detect and characterize gene-gene interactions. We found a significant interaction between eNOS rs743506 and iNOS 2087G/A polymorphisms in migraine patients compared to control group (P < 0.05), suggesting that this combination affect the susceptibility to migraine. Further studies are needed to determine the molecular mechanisms explaining this interaction.

Time course involvement of matrix metalloproteinases in the vascular alterations of renovascular hypertension

Increased vascular matrix metalloproteinases (MMPs) levels play a role in late phases of hypertensive vascular remodeling. However, no previous study has examined the time course of MMPs in the various phases of two-kidney, one-clip hypertension (2K1C). We examined structural vascular changes, collagen and elastin content, vascular oxidative stress, and MMPs levels/activities during the development of 2K1C hypertension. Plasma angiotensin converting enzyme (ACE) activity was measured to assess renin-angiotensin system activation. Sham or 2K1C hypertensive rats were studied after 2, 4, 6, and 10weeks of hypertension. Systolic blood pressure (SBP) was monitored weekly. Morphometry of structural changes in the aortic wall was studied in hematoxylin/eosin, orcein and picrosirius red sections. Aortic NADPH activity and superoxide production was evaluated. Aortic gelatinolytic activity was determined by in situ zymography, and MMP-2, MMP-14, and tissue inhibitor of MMPs (TIMP)-2 levels were determined by gelatin zymography, immunofluorescence and immunohistochemistry. 2K1C hypertension was associated with increased ACE activity, which decreased to normal after 10 weeks. We found increased aortic collagen and elastin content in the early phase of hypertension, which were associated with vascular hypertrophy, increased vascular MMP-2 and MMP-14 (but not TIMP-2) levels, and increased gelatinolytic activity, possibly as a result of increased vascular NADPH oxidase activity and oxidative stress. These results indicate that vascular remodeling of renovascular hypertension is an early process associated with early increases in MMPs activities, enhanced matrix deposition and oxidative stress. Using antioxidants or MMPs inhibitors in the early phase of hypertension may prevent the vascular alterations of hypertension.

Inducible nitric oxide synthase haplotype associated with migraine and aura

Migraine is a complex neurological disorder with a clear neurogenic inflammatory component apparently including enhanced nitric oxide (NO) formation. Excessive NO amounts possibly contributing to migraine are derived from increased expression and activity of inducible NO synthase (iNOS). We tested the hypothesis that two functional, clinically relevant iNOS genetic polymorphisms (C(-1026)A-rs2779249 and G2087A-rs2297518) are associated with migraine with or without aura. We studied 142 healthy women without migraine (control group) and 200 women with migraine divided into two groups: 148 with migraine without aura (MWA) and 52 with aura (MA). Genotypes were determined by real-time polymerase chain reaction using the Taqman(®) allele discrimination assays. The PHASE 2.1 software was used to estimate the haplotypes. The A allele for the G2087A polymorphism was more commonly found in the MA group than in the MWA group (28 vs. 18%; P < 0.05). No other significant differences in the alleles or genotypes distributions were found (P > 0.05). The haplotype combining both A alleles for the two polymorphisms was more commonly found in the MA group than in the control group or in the MWA group (19 vs. 10 or 8%; P = 0.0245 or 0.0027, respectively). Our findings indicate that the G2087A and the C(-1026)A polymorphism in the iNOS gene affect the susceptibility to migraine with aura when their effects are combined within haplotypes, whereas the G2087A affects the susceptibility to aura in migraine patients. These finding may have therapeutic implications when examining the effects of selective iNOS inhibitors.

Chronic ethanol consumption reduces adrenomedullin-induced relaxation in the isolated rat aorta

Adrenomedullin (AM) is a peptide that displays cardiovascular protective activity. We investigated the effects of chronic ethanol consumption on vascular reactivity to AM and the expression of AM system components in the rat aorta. Male Wistar rats were treated with ethanol (20% vol/vol) for 6 weeks. Vascular reactivity experiments were performed in the isolated rat aorta. Metalloproteinase-2 (MMP-2) levels were determined by gelatin zymography. Nitrite and nitrate generation was measured by chemiluminescence. Protein and mRNA levels of pre-pro-AM, calcitonin receptor-like receptor (CRLR) and RAMP1, 2, and 3 (receptor-activity-modifying proteins) were assessed by western blot and quantitative real-time polymerase chain reaction, respectively. Ethanol intake reduced AM-induced relaxation in endothelium-intact rat aortas, whereas calcitonin gene-related peptide-, acetylcholine-, and sodium nitroprusside-induced relaxation were not affected by ethanol intake. N(G)-nitro-l-arginine-methyl-ester (l-NAME), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, and tetraethylammonium reduced AM-induced relaxation in aortic rings from both control and ethanol-treated rats. Ethanol consumption did not alter basal levels of nitrate and nitrite, nor did it affect the expression of MMP-2 in the rat aorta. Ethanol consumption increased mRNA levels of pre-pro-AM and RAMP1. Protein levels of AM, CRLR, and RAMP1, 2, and 3 were not affected by ethanol consumption. The major findings of the present study are that ethanol consumption reduces the vascular relaxation induced by AM and changes the mRNA expression of the components of the AM system in the vasculature. This response could be one of the mechanisms by which ethanol predisposes individuals to vascular dysfunction and hypertension.

Ethanol consumption increases the expression of endothelial nitric oxide synthase, inducible nitric oxide synthase and metalloproteinases in the rat kidney

Objectives

The effects of longterm ethanol consumption on the levels of nitric oxide (NO) and the expression of endothelial NO synthase (eNOS), inducible NO synthase (iNOS) and metalloproteinase-2 (MMP-2) were studied in rat kidney.

Methods

Male Wistar rats were treated with 20% ethanol (v/v) for 6 weeks. Nitrite and nitrate generation was measured by chemiluminescence. Protein and mRNA levels of eNOS and iNOS were assessed by immunohistochemistry and quantitative real-time polymerase chain reaction, respectively. MMP-2 activity was determined by gelatin zymography. Histopathological changes in kidneys and indices of renal function (creatinine and urea) and tissue injury (mitochondrial respiration) were also investigated.

Results

Chronic ethanol consumption did not alter malondialdehyde levels in the kidney. Ethanol consumption induced a significant increase in renal nitrite and nitrate levels. Treatment with ethanol increased mRNA expression of both eNOS and iNOS. Immunohistochemical assays showed increased immunostaining for eNOS and iNOS after treatment with ethanol. Kidneys from ethanol-treated rats showed increased activity of MMP-2. Histopathological investigation of kidneys from ethanol-treated animals revealed tubular necrosis. Indices of renal function and tissue injury were not altered in ethanol-treated rats.

Conclusions

Ethanol consumption increased renal metalloproteinase expression/activity, which was accompanied by histopathological changes in the kidney and elevated NO generation. Since iNOS-derived NO and MMPs contribute to progressive renal injury, the increased levels of NO and MMPs observed in ethanol-treated rats might contribute to progressive renal damage.

Ethanol consumption alters the expression and reactivity of adrenomedullin in the rat mesenteric arterial bed

AIMS

Adrenomedullin (AM) is a peptide that displays cardiovascular protective activity. We investigated the effects of chronic ethanol consumption on arterial blood pressure, vascular reactivity to AM and the expression of AM system components in the rat mesenteric arterial bed (MAB).

METHODS

Male Wistar rats were treated with ethanol (20% vol/vol) for 6 weeks. Systolic, diastolic and mean arterial blood pressure were monitored in conscious rats. Vascular reactivity experiments were performed on isolated rat MAB. Matrix metalloproteinase-2 (MMP-2) levels were determined by gelatin zymography. Nitrite and nitrate generation were measured by chemiluminescence. Protein and mRNA levels of pre-pro-AM, CRLR (calcitonin receptor-like receptor) and RAMP1, 2 and 3 (receptor activity-modifying proteins) were assessed by western blot and quantitative real-time polymerase chain reaction, respectively.

RESULTS

Ethanol consumption induced hypertension and decreased the relaxation induced by AM and acetylcholine in endothelium-intact rat MAB. Phenylephrine-induced contraction was increased in endothelium-intact MAB from ethanol-treated rats. Ethanol consumption did not alter basal levels of nitrate and nitrite, nor did it affect the expression of MMP-2 or the net MMP activity in the rat MAB. Ethanol consumption increased mRNA levels of pre-pro-AM and protein levels of AM in the rat MAB. Finally, no differences in protein levels or mRNA of CRLR and RAMP1, 2 and 3 were observed after treatment with ethanol.

CONCLUSION

Our study demonstrates that ethanol consumption increases blood pressure and the expression of AM in the vasculature and reduces the relaxation induced by this peptide in the rat MAB.

Endothelial nitric oxide synthase haplotypes associated with aura in patients with migraine

There is strong evidence implicating nitric oxide (NO) in the pathophysiology of migraine and aura. Therefore, genetic polymorphisms in the endothelial NO synthase (eNOS) gene have been studied as candidate markers for migraine susceptibility. We compared for the first time the distribution of eNOS haplotypes including the three clinically relevant eNOS polymorphisms (T(-786)C in the promoter, rs2070744; Glu298Asp in exon 7, rs1799983; and a 27 bp variable number of tandem repeats in intron 4) and two additional tagging single-nucleotide polymorphisms (rs3918226 and rs743506) in 178 women with migraine (134 without aura and 44 with aura) and 117 healthy controls (control group). Genotypes were determined by TaqMan allele discrimination assay, real-time polymerase chain reaction, and polymerase chain reaction followed by fragment separation by electrophoresis. The GA (rs743506) genotype was more common in the control group than in women with migraine (odds ratio = 0.47, 95% confidence interval [CI] = 0.29-0.78, p < 0.01). No significant differences were found in allele distributions for the five eNOS polymorphisms. However, the haplotypes including the variants "C C a Glu G" and the variants "C C b Glu G" were more common in women with migraine with aura than in women with migraine without aura (odds ratio = 30.71, 95% CI = 1.61-586.4 and odds ratio = 17.26, 95% CI = 1.94-153.4, respectively; both p < 0.0015625). These findings suggest that these two eNOS haplotypes affect the susceptibility to the presence of aura in patients with migraine.

Comparative study on antioxidant effects and vascular matrix metalloproteinase-2 downregulation by dihydropyridines in renovascular hypertension

The vascular remodeling associated with hypertension involves oxidative stress and enhanced matrix metalloproteinases (MMPs) expression/activity, especially MMP-2. While previous work showed that lercanidipine, a third-generation dihydropyridine calcium channel blocker (CCB), attenuated the oxidative stress and increased MMP-2 expression/activity in two-kidney, one-clip (2K1C) hypertension, no previous study has examined whether first- or second-generation dihydropyridines produce similar effects. We compared the effects of nifedipine, nimodipine, and amlodipine on 2K1C hypertension-induced changes in systolic blood pressure (SBP), vascular remodeling, oxidative stress, and MMPs levels/activity. Sham-operated and 2K1C rats were treated with water, nifedipine 10 mg/kg/day, nimodipine 15 mg/kg/day, or amlodipine 10 mg/kg/day by gavage, starting 3 weeks after hypertension was induced. SBP was monitored weekly. After 6 weeks of treatment, quantitative morphometry of structural changes in the aortic wall was studied in hematoxylin/eosin-stained sections. Aortic and systemic reactive oxygen species levels were measured by using dihydroethidine and thiobarbituric acid-reactive substances (TBARs), respectively. Aortic MMP-2 levels and activity were determined by gelatin zymography, in situ zymography, and immunofluorescence. Nifedipine, nimodipine, or amlodipine attenuated the increases in SBP in hypertensive rats by approximately 17% (P < 0.05) and prevented vascular hypertrophy (P < 0.05). These CCBs blunted 2K1C-induced increases in vascular oxidative stress and plasma TBARs concentrations (P < 0.05). All dihydropyridines attenuated the increases in aortic MMP-2 levels and activity associated with 2K1C hypertension. These findings suggest lack of superiority of one particular dihydropyridine, at least with respect to antioxidant effects, MMPs downregulation, and inhibition of vascular remodeling in hypertension.