Effects of vitamin C treatment on collar-induced intimal thickening

Vitamin C has efficient antioxidant properties and is involved in important physiological processes such as collagen synthesis. As such, vitamin C deficiency leads to serious complications, including vascular diseases. The aim of this study was to investigate the effects of vitamin C treatment on collar-induced intimal thickening. Rabbits were fed a normocholesterolemic diet and a non-occlusive silicon collar was placed around the left carotid artery for 3, 7, and 14 days. The rabbits were treated with or without vitamin C (150 mg/kg/day). Collar-induced intimal thickening became apparent at day 7. The effect of the collar on intimal thickening was more prominent at day 14. Vitamin C treatment significantly inhibited collar-induced intimal thickening at day 14. The placement of the collar around the carotid artery decreased maximum contractile responses against contractile agents (KCl, phenylephrine, 5-hydroxytryptamine). The effect of the collar on contractile responses was enhanced as days elapsed. Decreased contractile responses of collared carotid arteries normalized at day 14 in the vitamin C treatment group. Vitamin C treatment also restored sensitivity to phenylephrine. The collar also significantly decreased acetylcholine-induced relaxations at day 3 and day 7. Acetylcholine-induced relaxations normalized in collared-arteries in the placebo group at day 14. Vitamin C treatment significantly increased acetylcholine-induced relaxations of both normal and collared carotid arteries at day 14. MMP-9 expression increased in collared arteries at day 3 and day 7 but did not change at day 14. MMP-2 expression increased in collared arteries at day 14. However, vitamin C treatment reduced collar-stimulated expression of MMP-2 at day 14. These findings indicate that vitamin C may have potentially beneficial effects on the early stages of atherosclerosis. Furthermore these results, for the first time, may indicate that vitamin C can also normalize decreased contractile response through perivascular collar placement

Zoledronate upregulates MMP-9 and -13 in rat vascular smooth muscle cells by inducing oxidative stress

WOS: 000374502300001PubMed ID: 27143852Background: Bisphosphonates, including zoledronate, target osteoclasts and are widely used in the treatment of osteoporosis and other bone resorption diseases, despite side effects that include damaging the stomach epithelium. Beneficial and adverse effects on other organ systems, including the cardiovascular system, have also been described and could impact on the use of bisphosphonates as therapeutic agents. Vascular smooth muscle cells (VSMCs) are major constituents of the normal vascular wall and have a key role in intimal thickening and atherosclerosis, in part by secreting MMPs that remodel the extracellular matrix and cleave cell surface proteins or secreted mediators. In this study, we investigated the effects of zoledronate on MMP expression. Methods: Rat VSMCs were stimulated by PDGF (50 ng/mL) plus TNF-alpha (10 ng/mL) or left unstimulated for a further 24 hours in serum-free medium. In other series of experiments, cells were pre-treated either with SC-514 (50 mu M) or with apocynin (20 nM) for 2 hours, then zoledronate (100 mu M) was added into 2% fetal calf serum containing medium for 24 hours. Results and discussion: Using isolated rat VSMCs in culture, zoledronate (100 mu M) increased MMP-9 and -13 mRNA expressions but inhibited MMP-2 expression. MMP-9 and MMP-13 up-regulation was shown to depend on the NF-kappa B pathway; and this was activated by zoledronate. Furthermore, zoledronate elevated the levels of reactive oxygen species detected by either dichlorofluorescein in isolated VSMCs or lucigenin enhanced chemiluminescence in rat aortic rings in vitro. Apocynin, an inhibitor of NADPH oxidase, reversed NF-kappa B activation and MMP-9 and MMP-13 up-regulation by zoledronate. Conclusion: We conclude that zoledronate increases MMP-9 and MMP-13 expressions in rat VSMCs dependent upon stimulation of the NF-kappa B pathway by reactive oxygen species. Effects on MMP expression may contribute to the pharmacologic profile of bisphosphonates.British Heart FoundationBritish Heart Foundation [CH95/001]; British Heart FoundationBritish Heart Foundation [RG/09/006/27918]The authors would like to thank Dr Goksel Gokce, Ege University Faculty of Pharmacy and Dr Steve White, University of Bristol for valuable help and expertise on oxidative stress measurements. MZA would also like to thank Prof Levent Ustunes for kind help and encouragement. This study was supported by the British Heart Foundation grant CH95/001

Sıçan aortasında endotelyum kaynaklı gevşemeler üzerine c vitamininin etkisi

Human arteries show endothelial dysfunction in a variety of conditions, including atherosclerosis, hypercholesterolemia, smoking and hypertension. This dysfunction manifests as a loss of endothelium dependent vasodilation to acetylcholine or shear stress, and is typically associated with decreased generation of nitric oxide (NO) by the endothelium. It has been shown that vitamin C (ascorbic acide), when infused or chronically ingested improves the defective endothelium-dependent vasodilation present in these clinical conditions. Since oxidative stress inhibits the biological activity of NO, vitamin C as an antioxidant may be protective. In this study, we investigated the ability of ascorbate to protect the loss of endothelium-dependent relaxation by reaxtive oxygen species and we also examined its relaxant effects on vascular smooth muscle. An oxidant stress applied to rat aortic rings by the electrolyses of the bathing solution (20 mA, DC current, 5 min). Endothelium-dependent relaxation in response to acetylcholine of precontracted aortic rings was attenuated when the rings were exposed to electrolyses-induced reaxtive oxygen species (Emax, control %55±3, electrolyses %10±3, P0.001; pD2, control 6.96±0.12, electrolyses 5.98±0.17, P0.01). Incubation prior to electrolyses with vitamin C (3 mM) protected the aortic rings against the impairement of endothelium-dependent relaxation (Emax, control %63±6, electrolysis %56±7; pD2, control 7.10±0.18, electrolysis 6.69±0.22) by oxidant stress. Ascorbic acid induced concentration-dependent relaxations in rat aorta rings comprising two phases. The first, a dose-related relaxation was seen between 100-300 ?M and reached a maximum of %28?4. This first relaxation phase was abolished by endothelial removal (%10±2, P 0.001) or treatment with L-NA (%13±3, P 0.01). The second phase was a dose-dependent and pH related relaxation to concentrations of ascorbic acid above 1 mM with a steeper slope. The maximum relaxation (%70?4) induced by 3 mM ascorbic acid in this phase was also partially abolished by endothelial removal (%51±5, P 0.01) or treatment with L-NA (%45±3, P 0.001). In conclusion, our findings show that ascorbic acid prevents NO-dependent endothelial relaxations from to the attacks of superoxide radicals and produced concentration-dependent relaxation of rat aorta rings comprising two components: the first, which was seen at lower concentrations, related to vascular endothelium and the second, more powerful one related to asidic ability of ascorbic acid.Sağlıklı bireylerde, damar yatağındaki endotelyumdan nitrik oksit salıverilir ve nitrik oksit vasküler düz kas üzerinde gevşetici etkiler yapar. Hipertansiyon, ateroskleroz ve diyabet gibi vasküler hastalıkların endotelyumdaki bozulma ile ilişkili olduğu pek çok çalışmada gösterilmiştir. Klinik çalışmalar C vitamini (askorbik asit)'in endoteyuma bağlı gevşeme yanıtlarındaki azalmayı restore ettiğini göstermiştir. Oksidatif stresin ateroskleroz patojenezinde rol oynayabileceği yolundaki görüşler son yıllarda destek bulmaktadır. Oksidatif stres sonucu türeyen süperoksit anyonlarının nitrik oksitin hızlı yıkılımına yol açtığı ve gevşetici etkisini yitirmesine neden olduğu genel olarak kabul edilmektedir. Bu durum doğal bir antioksidan olan C vitamininin önemini artırmaktadır. Bu bilgiler ışığında, izole sıçan aorta preparatında gerçekleştirilen çalışmamızda, C vitaminin damar düz kası üzerinde doğrudan gevşetici bir etkisinin olup olmadığı; eğer böyle bir etkiye sahipse bunda endotelyum ve NO'nun rolünün ne olduğu ve antioksidan özelliğinin endotelyumu oksidatif stresin bozucu etkilerine karşı koruyup korumadığı araştırılmıştır. Askorbik asit, sıçan aorta ringlerinde konsantrasyona bağlı olarak artan gevşeme yanıtları meydana getirmiştir. Bir gevşeme yanıtının esasen iki ayrı fazdan oluştuğu belirlenmiştir. Birinci fazın 100-300 mM aralığında maksimuma ulaştığı (%28±4) ve endotelyumun sıyrılması (%10±2) veya L-NA (%13±3) ile inkübasyon sonucu önemli ölçüde inhibe olduğu gösterilmiştir. İkinci faz gevşeme yanıtı yaklaşık 1 mM konsantrasyon düzeyinde başlamış ve 3 mM'da maksimuma (%70±4) ulaşmıştır. İkinci faz gevşeme yanıtlarının daima izole organ banyosu çözeltisinin pH'sındaki düşüşle eş zamanlı olduğu bulunmuştur. İzole organ banyosuna yerleştirilen platin elektrodlardan 5 dakika süreyle 20 mA doğru akım geçirilerek (elektroliz) sıçan aorta halklarında oluşturulan oksidatif stres, asetilkoline karşı maksimum gevşeme yanıtını (Emaks, kontrol %55±3, elektroliz %10±3, P0.001) ve duyarlığı (pD2, kontrol 6.96±0.12, elektroliz 5.98±0.17, P0.01) önemli ölçüde azaltmış, fakat nitrogliserin gevşeme yanıtlarını etkilememiştir. Elektroliz öncesi askorbik asit (3 mM) ile inkübasyonun asetilkolin gevşeme yanıtlarını oskidatif stresin bozucu etkilerine karşı koruduğu (Emaks, kontrol %63±6, elektroliz %56±7; pD2, kontrol 7.10±0.18, elektroliz 6.69±0.22) gösterilmiştir. Sonuç olarak, bu çalışmada C vitamininin endotele bağımlı vazodilatasyonu oksidatif stresin olumsuz etkilerine karşı koruduğu, kümülatif olarak artan konsantrasyonlarda damar düz kasında iki bileşenli bir vazodilatasyon (düşük dozlarda endotelyuma, yüksek dozlarda pH'ya bağlı) yanıtı oluşturduğu gösterilmişti

Ergothioneine prevents endothelial dysfunction induced by mercury chloride

WOS: 000435174400014PubMed ID: 29805489Exposure to mercury has detrimental effects on the cardiovascular system, particularly the vascular endothelium. The present study aimed to investigate the effects of ergothioneine (EGT) on endothelial dysfunction induced by low-dose mercury chloride (HgCl2). Agonist-induced contractions and relaxations were evaluated in isolated aortic rings from 3-month-old male Wistar rats treated by intra-muscular injection to caudal hind leg muscle with HgCl2 (first dose, 4.6 mu g/kg; subsequent doses, 0.07 mu g/kg/day for 15 days) and optionally with EGT (2 mu g/kg for 30 days). Reactive oxygen species (ROS) in aortic rings were measured by means of lucigenin- and luminol-enhanced chemiluminescence. The protein level of endothelial nitric oxide synthase was evaluated by ELISA. Blood glutathione (GSH) and catalase levels, lipid peroxidation and total nitrite were measured spectrophotometrically. The results indicated that low-dose HgCl2 administration impaired acetylcholine (ACh)-induced relaxation and potentiated phenylephrine-and serotonin-induced contractions in rat aortas. In addition, HgCl2 significantly increased the levels of ROS in the aortic tissue. EGT prevented the loss of ACh-induced relaxations and the increase in contractile responses. These effects were accompanied by a significant decrease in ROS levels. EGT also improved the ratio of reduced GSH to oxidized GSH and catalase levels with a concomitant decrease in lipid peroxidation. In conclusion, to the best of our knowledge, the present study was the first to report that EGT prevents endothelial dysfunction induced by low-dose HgCl2 administration. EGT may serve as a therapeutic tool to reduce mercury-associated cardiovascular complications via improving the antioxidant status.Scientific Research Fund of Ege University, Izmir, Turkey [09-ECZ-024]This study was supported by the Scientific Research Fund of Ege University, Izmir, Turkey (grant no. 09-ECZ-024)

Effects of vitamin C treatment on collar-induced intimal thickening

WOS: 000366530900003PubMed ID: 26719672Vitamin C has efficient antioxidant properties and is involved in important physiological processes such as collagen synthesis. As such, vitamin C deficiency leads to serious complications, including vascular diseases. The aim of this study was to investigate the effects of vitamin C treatment on collar-induced intimal thickening. Rabbits were fed a normocholesterolemic diet and a non-occlusive silicon collar was placed around the left carotid artery for 3, 7, and 14 days. The rabbits were treated with or without vitamin C (150 mg/kg/day). Collar-induced intimal thickening became apparent at day 7. The effect of the collar on intimal thickening was more prominent at day 14. Vitamin C treatment significantly inhibited collar-induced intimal thickening at day 14. The placement of the collar around the carotid artery decreased maximum contractile responses against contractile agents (KCl, phenylephrine, 5-hydroxytryptamine). The effect of the collar on contractile responses was enhanced as days elapsed. Decreased contractile responses of collared carotid arteries normalized at day 14 in the vitamin C treatment group. Vitamin C treatment also restored sensitivity to phenylephrine. The collar also significantly decreased acetylcholine-induced relaxations at day 3 and day 7. Acetylcholine-induced relaxations normalized in collared-arteries in the placebo group at day 14. Vitamin C treatment significantly increased acetylcholine-induced relaxations of both normal and collared carotid arteries at day 14. MMP-9 expression increased in collared arteries at day 3 and day 7 but did not change at day 14. MMP-2 expression increased in collared arteries at day 14. However, vitamin C treatment reduced collar-stimulated expression of MMP-2 at day 14. These findings indicate that vitamin C may have potentially beneficial effects on the early stages of atherosclerosis. Furthermore these results, for the first time, may indicate that vitamin C can also normalize decreased contractile response through perivascular collar placement.Scientific Research Foundation of Ege University, Izmir, TurkeyEge UniversityThis research was supported by the Scientific Research Foundation of Ege University, Izmir, Turkey

Doxycycline down-regulates matrix metalloproteinase expression and inhibits NF-κB signaling in LPS-induced PC3 cells

Introduction. Matrix metalloproteinase enzymes (MMPs) play important role in inflammation, malignant cell proliferation, invasion and angiogenesis by mediating extracellular matrix degradation. Doxycycline, a synthetic tetracycline, behaves as a MMP inhibitor at a subantimicrobial dose and inhibits tumor cell proliferation, invasion and angiogenesis. The aberrant activity of nuclear factor kappa B (NF-κB) causes activation of MMPs and thereby proliferation and invasion of cancer cells. The aim of this study was to investigate the effects of doxycycline on the expression of MMPs in lipopolysaccharide (LPS)-induced PC3 human prostate cancer cells and the possible role of NF-κB signaling. Material and methods. PC3 cells were incubated with LPS (0.5 μg/mL) for 24 h in the presence or absence of doxycycline (5 μg/mL). The effects of LPS and doxycycline on the expressions of MMP-2, MMP-8, MMP-9, MMP-10, NF-κB/p65, IκB-α, p-IκB-α, IKK-β were examined by Western blotting and immunohistochemistry in PC3 cells. Furthermore, relative proteinase activities of MMP-2 and MMP-9 were determined by gelatin zymography. Results. LPS increased expression and activity of MMP-9 and expression of MMP-8, MMP-10, NF-κB /p65, p-IκB-α, IKK-β and doxycycline down-regulated its effects with the exception of MMP-10 expression. The expression of MMP-2 and IκB-α was affected by neither LPS nor doxycycline. Conclusions. Our findings indicate that doxycycline inhibits the expression of various MMPs and NF-κB signaling may play a role in the regulation of MMPs expression in LPS-induced PC3 human prostate cancer cells

FACTORS AFFECTING DRUG INTERACTIONS AND THEIR CLINICAL IMPORTANCE IN GERIATRIC OUTPATIENTS

Introduction: Polypharmacy can lead to drug-drug interactions. The aim of this study was to determine the possible factors affecting the prevalence and clinical importance, and interrater reliability of clinical significance of drug interactions in geriatric outpatients. Materials and Method: Potential drug-drug interactions in 228 patients treated in an outpatient geriatric clinic were evaluated in this cross-sectional, retrospective study. The potential significance of the interactions was reviewed separately by a geriatrician and a clinical pharmacist.Results: A total of 1342 drugs were prescribed (median 6 [2-14], per patient). Mean age of the patients was 78 ; PLUSMN;0.5 (65-96). Polypharmacy was present in 64.0% of the patients. A weak positive correlation was found between patient age and the number of drugs used (Rs =.205; p=.002). No drug interaction was detected in 18.0% of the patients. In the prescriptions of the remaining 187 patients 760 category C, 70 category D, and 18 category X interactions (Lexicomp ; REG;) were detected. A strong positive correlation was found between the number of drugs per patient and the number of drug interactions (Rs =.734; p.001). There was a strong correlation between the number of interactions and the presence of polypharmacy (rpb=.702, p.001). The measure of agreement between the clinicians was more pronounced for category D and X interactions (Cohen's K=.714 and 1, p.001).Conclusion: Advanced age, a higher frequency of concomitant use of drugs, and polypharmacy are factors that require clinicians to be aware of drug-drug interactions. Clinical pharmacists can work with geriatricians in outpatient clinics to prevent drug interactions

Low-dose doxycycline inhibits hydrogen peroxide-induced oxidative stress, MMP-2 up-regulation and contractile dysfunction in human saphenous vein grafts

WOS: 000469125200001PubMed ID: 31213768Background: Cardiopulmonary bypass (CPB) applied during coronary artery bypass grafting (CABG), promotes inflammation, generation of reactive oxygen species (ROS) and up-regulation of matrix metalloproteinases (MMPs). All these complications may lead to contractile dysfunction, restenosis and early graft failure, restricting long-term efficacy of bypass grafts. Low-dose doxycycline is a potent MMP inhibitor and ROS scavenger. In this study, we aimed to investigate the effects of doxycycline on ROS generation, MMP regulation and contractile dysfunction induced by H2O2 in human saphenous vein (HSV) grafts. Methods: HSV grafts (n=7) were divided into four groups after removing endothelial layer by mechanical scratching and incubated with 10 mu M H2O2 and/or 10 mu M doxycycline for 16 hrs. Untreated segments served as control. Concentration-response curves to noradrenaline (NA), potassium chloride (KCl), serotonin (5-HT) and papaverine were performed. Superoxide anion and other ROS levels were determined by using lucigenin- and luminol-enhanced chemiluminescence assays, respectively. Expression/activity of gelatinases (MMP-2/MMP-9) was examined by gelatin zymography. MMP-13 expression was evaluated by immunostaining/immunoscoring. Results: H2O2 incubation increased superoxide anion and other ROS levels. Doxycycline prevented these increments. H2O2 suppressed contractile responses to NA, KCl and 5-HT. Doxycycline ameliorated contractions to NA and KCl but not to 5-HT. H2O2 or doxycycline did not altered relaxation to papaverine. MMP-2 and MMP-13 expression increased with H2O2, but doxycycline inhibited MMP-2 up-regulation/activation. Conclusion: Low-dose doxycycline may have beneficial effects on increased oxidative stress, MMP up-regulation/activation and contractile dysfunction in HSV grafts.Scientific Research Foundation of Ege UniversityEge UniversityThe authors would like to thank to Prof. Bekir Ugur Ergur for contributions to immunohistochemical analyses, to Hatice Uluer for valuable statistical consultancy and to Scientific Research Foundation of Ege University for the financial support