Caffeine Increases Apolipoprotein A-1 and Paraoxonase-1 but not Paraoxonase-3 Protein Levels in Human-Derived Liver (HepG2) Cells

Background: Apolipoprotein A-1, paraoxonase-1 and paraoxonase-3 are antioxidant and anti-atherosclerotic structural high-density lipoprotein proteins that are mainly synthesized by the liver. No study has ever been performed to specifically examine the effects of caffeine on paraoxonase enzymes and on liver apolipoprotein A-1 protein levels. Aims: To investigate the dose-dependent effects of caffeine on liver apolipoprotein A-1, paraoxonase-1 and paraoxonase-3 protein levels. Study Design: In vitro experimental study. Methods: HepG2 cells were incubated with 0 (control), 10, 50 and 200 ?M of caffeine for 24 hours. Cell viability was evaluated by 3-(4,5-Dimethyl-2-thiazolyl)-2,5- diphenyl-2H-tetrazolium bromide assay. ApolipoproteinA-1, paraoxonase-1 and paraoxonase-3 protein levels were measured by western blotting. Results: We observed a significant increase on apolipoprotein A-1 and paraoxonase-1 protein levels in the cells incubated with 50 µM of caffeine and a significant increase on paraoxonase-1 protein level in the cells incubated with 200 µM of caffeine. Conclusion: Our study showed that caffeine does not change paraoxonase-3 protein level, but the higher doses used in our study do cause an increase in both apolipoprotein A-1 and paraoxonase-1 protein levels in liver cell

Serum osteopontin levels in patients with psoriasis vulgaris and its relation with oxidative stress

Background and Design: Oxidative stress is known to play a role in the etiopathogenesis of psoriasis. Recent data suggest that osteopontin (OPN) can also play a role in the pathogenesis of psoriasis. In the current study, OPN levels and oxidative stress were evaluated in patients with psoriasis. Materials and Methods: The study included 61 patients with psoriasis and 62 healthy controls. The OPN levels, total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were measured using serum. The disease severity was evaluated using the psoriasis area and severity index (PASI). Results: No statistically significant differences in OPN, TAS, and OSI values were identified between the psoriasis and control groups. A negative correlation was found with the TAS. There was no statistically significant correlation between the PASI score and OPN, TAS, TOS, and OSI values. Conclusion: We did not find a statistically significant correlation between OPN levels and oxidative stress in patients with psoriasis. We believe that larger and more detailed studies are needed to highlight the role of OPN and oxidative stress in the etiopathogenesis of psoriasis

Investigation of nitric oxide metabolism in streptozotocin induced diabetes

Doktora TeziBu çalışmanın amacı, streptozotosin ile diyabet oluşturulan sıçanlarda L-karnitinin plazma ve karaciğerde nitrik oksit metabolizması üzerine etkisini incelemektir. Sprague Dawley dişi sıçanlar, kontrol, L-karnitin, diyabet ve diyabet+L-karnitin olmak üzere rastgele gruplara ayrıldı. Diyabet ve diyabet+L-karnitin gruplarına sitrat tamponunda (pH 4.5) hazırlanmış tek doz streptozotosin (40 mg/kg) intraperitoneal olarak enjekte edildi. Diğer gruplara sitrat tamponu intraperitoneal olarak enjekte edildi. Streptozotosin enjeksiyonundan 72 saat sonra 15 gün boyunca L-karnitin ve diyabet+L-karnitin gruplarına L-karnitin (500 mg/kg/gün) verildi. Diğer gruplara 15 gün boyunca serum fizyolojik intraperitoneal olarak verildi. Kan glukozu (72. saatte ve deney sonunda), karaciğer dokusu nitrik oksit ve indüklenebilir nitrik oksit sentaz, plazma nitrik oksit ve nitrotirozin düzeyleri ölçüldü. Diyabetik grupların kan glukoz düzeyleri, diğer gruplara göre anlamlı derecede yüksekti. Diyabet+L-karnitin grubunun kan glukozu değişim yüzdesi, diğer gruplara göre düşüktü. Aynı zamanda plazma nitrik oksit düzeyi kontrol grubuna göre yüksekti. Diyabet grubunun plazma nitrotirozin düzeyi, L-karnitin uygulanan gruplara göre yüksekti. Grupların karaciğer indüklenebilir nitrik oksit sentaz ve nitrik oksit düzeyleri arasında fark yoktu. Sonuç olarak çalışmamız; deneysel diyabette 15. gün sonunda plazma ve karaciğer nitrik oksit ve karaciğer indüklenebilir nitrik oksit sentaz düzeylerinin değişmediğini ancak plazma nitrotirozin düzeyinin arttığını gösterdi. Diğer yandan çalışmamız, L-karnitinin plazma nitrik oksit düzeylerinde artışa, plazma nitrotirozin düzeylerinde azalmaya neden olduğunu, oysa karaciğer nitrik oksit ve indüklenebilir nitrik oksit sentaz düzeylerine etkisinin olmadığını gösterdi.AbstractThe aim of this study is to investigate the effect of L-carnitine on plasma and liver nitric oxide metabolism in streptozotocin-induced diabetic rats. Sprague Dawley female rats were divided randomly into following groups: control, L-carnitine, diabetes and diabetes+L-carnitine. Diabetes and diabetes+L-carnitine groups were intraperitonally injected with a single dose of streptozotocin (40 mg/kg) prepared in the citrate buffer (pH 4.5). Other groups were injected with only citrate buffer. 72 hours after the streptozotocin injection, L-carnitine (500 mg/kg/day) was given intraperitoneally to L-carnitine and diabetes+L-carnitine groups for 15 days. Physiological saline was given intraperitoneally to the other groups for 15 days. Blood sugar (at 72 hours and the end of experiment), liver nitric oxide and inducible nitric oxide synthase, plasma nitric oxide and nitrotyrosine levels were measured. Blood glucose levels in diabetic groups were higher compared with other groups. Percentage change of blood glucose in diabetes+L-carnitine group was lower compared with other groups. Also plasma nitric oxide levels in diabetes+L-carnitine group?s were higher than control group. Plasma nitrotyrosine level of diabetes group was higher than that of L-carnitine injected groups. There was no significant difference between the levels of liver inducible nitric oxide synthase and nitric oxide in groups. As a result, our study showed that plasma and liver nitric oxide and liver inducible nitric oxide synthase levels don?t change significantly but plasma nitrotyrosine level is increased at the end of 15th day of experimental diabetes. On the other hand, our results also showed that L-carnitine causes an increase in plasma nitric oxide levels and a decrease in plasma nitrotyrosine levels whereas it has no effect on liver nitric oxide and inducible nitric oxide synthase levels

Effect of caffeine on protein oxidation and endoslasmic reticulum stress in acrylamide-treated human-derived hepatoma cells

Çalışmamızın amacı, kafeinin akrilamid uygulanan insan kaynaklı hepatoma hücrelerinde protein oksidasyonu ve endoplazmik retikulum stresine etkisini araştırmaktır. Akrilamid ve akrilamid ile birlikte uygulanan kafeinin; hücre canlılığına etkisi 3-(4,5- dimetil-2-tiyazolil)-2,5-difenil-2H-tetrazolyum bromür testi ile, protein karbonil, glukozla ilişkili protein 78, transkripsiyon aktive edici faktör 4, C/EBP-homolog protein düzeyleri western blot yöntemiyle ölçüldü. HepG2 hücrelerine 24 saat süreyle uygulanan 1000 ve 10000 μM konsantrasyonlarında akrilamid hücre canlılığını anlamlı olarak azalttı (her ikisi için p<0.05). 10000 μM akrilamid, ER stres belirteci olan glukozla ilişkili protein 78, transkripsiyon aktive edici faktör 4, C/EBP-homolog protein düzeylerini anlamlı olarak arttırdı (tümü için p<0.05). Kafein uygulanan hücrelerde glukozla ilişkili protein 78, transkripsiyon aktive edici faktör 4, C/EBP-homolog protein düzeyleri anlamlı olarak değişmedi (tümü için p>0.05). Protein karbonil düzeyleri 24 saat süre ile 10000 μM akrilamid uygulanan hücrelerde kontrole göre anlamlı oranda yüksekti. 50 ve 200 μM kafein, 10000 μM akrilamid uygulanan hücrelerde protein karbonil düzeylerini anlamlı olarak önledi (ikisi için p<0.05). Sonuç olarak çalışmamız, HepG2 hücrelerinde akrilamidin 1000 ve 10000 μM konsantrasyonlarında hücre canlılığını azalttığını, protein oksidasyonu ve endoplazmik retikulum stresi arttırdığını, 10000 μM akrilamid ile birlikte uygulanan 10, 50 ve 200 μM kafeinin endoplazmik retikulum stresi değiştirmediğini ancak 50 ve 200 μM konsantrasyonlarında kafeinin protein oksidasyonunu önlediğini göstermiştir.Our study aims to investigate the effect of caffeine on protein oxidation and endoplasmic reticulum stress in human-induced hepatoma cells treated with acrylamide. The effect of caffeine administered with acrylamide and acrylamide on cell viability was measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, protein carbonyl, glucose regulated protein 78, activating transcription factor 4, C/EBPhomologous protein levels were measured by western blot method. Applied for 24 hours, 1000 and 10000 μM acrylamide significantly reduced the viability of HepG2 cells (for both p <0.05). 10000 μM acrylamide significantly increased the protein levels of glucose regulated protein 78, activating transcription factor 4, C/EBPhomologous protein (p<0.05 for all). The protein levels of glucose regulated protein 78, activating transcription factor 4, C/EBP-homologous protein were not significantly changed in 10, 50, 200 μM caffeine treated cells (p >0.05 for all). The protein carbonyl levels were significantly higher in cells treated with 10000 μM acrylamide compared to control. 50 and 200 μM caffeine significantly prevented protein carbonyl levels in cells treated with 10000 μM acrylamide (p <0.05 for both). As a result, our study showed that acrylamide decreases cell viability at concentrations of 1000 and 10000 μM in HepG2 cells, increases protein oxidation and endoplasmic reticulum stress, caffeine did not change endoplasmic reticulum stress, but doses of 50 and 200 μM caffeine prevent protein oxidatio