Tamara Nikolic

Mesenchymal stem cells protect from acute liver injury by attenuating hepatotoxicity of liver natural killer T cells in an inducible nitric oxide synthase- and indoleamine 2,3-dioxygenase-dependent manner.

The effects of mesenchymal stem cells (MSCs) on the phenotype and function of natural killer T (NKT) cells is not understood. We used concanavalin A (Con A) and α‐galactosylceramide (α‐GalCer)‐induced liver injury to evaluate the effects of MSCs on NKT‐dependent hepatotoxicity. Mouse MSCs (mMSCs) significantly reduced Con A‐ and α‐GalCer‐mediated hepatitis in C57Bl/6 mice, as demonstrated by histopathological and biochemical analysis, attenuated the influx of inflammatory [T‐bet+, tumour necrosis factor‐α (TNF‐α), interferon‐γ (IFN‐γ)‐producing and GATA3+, interleukin‐4 (IL‐4)‐producing] liver NKT cells and downregulated TNF‐α, IFN‐γ and IL‐4 levels in the sera. The liver NKT cells cultured in vitro with mMSCs produced lower amounts of inflammatory cytokines (TNF‐α, IFN‐γ, IL‐4) and higher amounts of immunosuppressive IL‐10 upon α‐GalCer stimulation. mMSC treatment attenuated expression of apoptosis‐inducing ligands on liver NKT cells and suppressed the expression of pro‐apoptotic genes in the livers of α‐GalCer‐treated mice. mMSCs reduced the cytotoxicity of liver NKT cells against hepatocytes in vitro. The presence of 1‐methyl‐dl‐tryptophan, a specific inhibitor of indoleamine 2,3‐dioxygenase (IDO), or l‐NG‐monomethyl arginine citrate, a specific inhibitor of inducible nitric oxide synthase (iNOS), in mMSC‐conditioned medium injected into α‐GalCer‐treated mice, counteracted the hepatoprotective effect of mMSCs in vivo and restored pro‐inflammatory cytokine production and cytotoxicity of NKT cells in vitro. Human MSCs attenuated the production of inflammatory cytokines in α‐GalCer‐stimulated human peripheral blood mononuclear cells in an iNOS‐ and IDO‐dependent manner and reduced their cytotoxicity against HepG2 cells. In conclusion, MSCs protect from acute liver injury by attenuating the cytotoxicity and capacity of liver NKT cells to produce inflammatory cytokines in an iNOS‐ and IDO‐dependent manner.

Mesenchymal stem cells protect from acute liver injury by attenuating hepatotoxicity of liver NKT cells in iNOS and IDO dependent manner

The effects of mesenchymal stem cells (MSCs) on phenotype and function of natural killer T (NKT) cells, is not understood. We used concanavalin A (ConA) - and α-galactosylceramide (α-GalCer)-induced liver injury to evaluate effects of MSCs on NKT-dependent hepatotoxicity. Mouse MSCs (mMSCs) significantly reduced Con A- and α-GalCer-mediated hepatitis in C57Bl/6 mice, as demonstrated by histopathological and biochemical analysis, attenuated influx of inflammatory (T-bet+ TNF-α, IFN-γ producing and GATA3+, IL-4-producing) liver NKT cells and down-regulated TNF-α, IFN-γ and IL-4 levels in the sera. The liver NKT cells cultured in vitro with mMSCs produced lower amounts of inflammatory cytokines (TNF-α, IFN-γ, IL-4) and higher amounts of immunosuppressive IL-10 upon α-GalCer stimulation. mMSC treatment attenuated expression of apoptosis-inducing ligands on liver NKT cells and suppressed the expression of pro-apoptotic genes in the livers of α-GalCer-treated mice. mMSCs reduced cytotoxicity of liver NKT cells against hepatocytes in vitro. The presence of 1-methyl-DL-tryptophan, a specific inhibitor of indoleamine 2,3-dioxygenase (IDO) or L-NG-monomethyl Arginine citrate, specific inhibitor of inducible nitric oxide synthase (iNOS), in mMSC-conditioned medium injected to α-GalCer-treated mice, counteracted the hepatoprotective effect of mMSCs in vivo, and restored pro-inflammatory cytokine production and cytotoxicity of NKT cells in vitro. Human MSCs in iNOS and IDO-dependent manner, attenuated the production of inflammatory cytokines in α-GalCer-stimulated human peripheral blood mononuclear cells and reduced their cytotoxicity against HepG2 cells. In conclusion, MSCs protect from acute liver injury by attenuating cytotoxicity and capacity of liver NKT cells to produce inflammatory cytokines in iNOS and IDO dependent manner.

MODULATION OF N-METHYL-D-ASPARTATE RECEPTORS IN ISOLATED RAT HEART

Considering the limited data on the role of NMDA-Rs in the cardiovascular system, the aim of the present study was to examine the effects of NMDA and DL-Hcy TLHC, alone and in combination with glycine, memantine, and ifenprodil, in the isolated rat heart. The hearts of Wistar albino rats were retrogradely perfused according to the Langendorff technique at a constant perfusion pressure. The experimental protocol for all experimental groups included the stabilization period, application of estimated substance for 5 min, followed by a washout period of 10 min. Using a sensor placed in the left ventricle, we registered the following parameters of myocardial function: dp/dtmax, dp/dtmin, SLVP, DVLP, HR; CF was measured using flowmetry). We estimated the following oxidative stress biomarkers in the coronary venous effluent using spectrophotometry: TBARS, NO2-, O2-, and H2O2. NMDA alone did not induce any change in any of the observed parameters, while DL-Hcy TLHC alone, as well as a combined application of NMDA and DL-Hcy TLHC with glycine, induced a reduction of most cardiodynamic parameters. Memantine and ifenprodil induced a reduction of cardiodynamic parameters and CF, as well as some oxidative stress biomarkers.

Redox Status in Patients with Femoral Neck Fractures

Abstract The femur transfers the body weight from the pelvic bone to the shinbone. Femur fractures are a significant cause of morbidity and mortality among the group of locomotor apparatus injuries, especially in the elderly population. Considering that oxidative stress occurs as a result of increased production of free radicals that damage cell function and cause numerous pathological conditions and diseases, the aim of this study was to investigate oxidative stress parameters in older patients with femoral neck fractures. This clinical study included 70 patients, of which 35 had femoral neck fractures (26 males and 9 females), while the other half of the patients formed the matched control group. Markers of oxidative stress (NO2−, TBARS, H2O2 and O2-) and anti-oxidative enzymes (SOD, CAT, and GSH) were measured. Results showed that the levels of O2- increased, while levels of NO2-, H2O2 and all the antioxidative enzymes decreased in patients with femoral neck fractures. These findings indicate that fractures cause oxidative stress, probably because of the reduced activity of osteoblasts and the increased activity of osteoclasts.

Atherogenic Impact of Homocysteine: Can HMG-CoA Reductase Inhibitors Additionally Influence Hyperhomocysteinaemia?

Abstract The strong association among the risk of coronary artery diseases (CAD), high levels of LDL-C and low levels of HDLC is well established. Hyperhomocysteinaemia (HHcy) is an independent risk factor for cardiovascular disease (CVD) and causes endothelial dysfunction, a hallmark of atherosclerosis. In this study, we ascertained the influence of statins on the atherogenic index, as an indicator and a significant adjunct for predicting atherosclerosis in hyperhomocysteinaemic male Wistar albino rats. For 4 weeks, the animals were fed with one of the following diets (Mucedola SRL., Milan, Italy): standard rodent chow; a diet enriched in methionine with no deficiency in B vitamins or a diet enriched in methio-nine and deficient in B vitamins. The animals were simultaneously exposed to a pharmacology treatment with atorvastatin at dose of 3 mg/kg/day i.p. or simvastatin, at dose of 5 mg/kg/day i.p. We measured weight gain, food intake, and FER and determined the concentrations of biochemical parameters of dyslipidaemia (TC, TGs, LDL-C, VLDL-C, and HDL-C), AI, and CRR. A histopathological examination was conducted on portions of the right and left liver lobes from each animal. A connection between Hhcy and dyslipidaemia was indicated by the findings of biochemical and histological analyses, suggesting that Hhcy was a pro-atherogenic state. An improvement in the lipid profile along with a decrease in the atherogenic index by statins suggests that atorvastatin and simvastatin could be useful antiatherogenic agents, with protective activities during hyperhomocysteinaemia.

Oxidative Stress Parameters after Abdominal Hysterectomy and their Relationships with Quality of Recovery

Abstract Study aimed to investigate relationship between oxidative stress markers and postoperative recovery in woman after abdominal hysterectomy, as well as to test the hypothesis that different analgesics differently influence redox status. The quality of recovery was evaluated with a QoR-40 questionnaire in fifty-one patients who underwent abdominal hysterectomy, preoperatively and on the 1st, 2nd, 3rd postoperative days (POD1,2,3). Blood samples were collected at baseline (T0), 3 (T1), 24 (T2), 48 (T3) and 72 (T4) hours after surgery. Oxidative stress markers concentrations (TBARS, NO2−, H2O2, O2− ) as well as antioxidative enzymes (SOD, CAT, and GSH) were analyzed. QoR-40 total score significantly declined on POD1 and POD2 and returned to baseline levels on POD3 (p<0.001). H2O2 levels significantly decreased from T0 to T3 and then, increased at T4 (p=0,011). Changes of TBARS and H2O2 from T0 to T3 showed significant and negative correlation (r=−0.303, p=0.046). There was no significant correlation between QoR-40 total score and any parameter of oxidative stress response (p>0.05). Changes in TBARS levels from T0 to T3 were statistically significant between the study subgroups primarily due to increase of the concentrations in patients receiving paracetamol (p=0.031). Patients age, duration of surgery and cigarette smoking status showed significant influcences on and association with some oxidative stress response markers (TBARS, O2−, CAT) (p<0.05). Women who underwent hysterectomy had significant changes of H2O2 and TBARS activity however, those changes were not associated with changes of QoR-40 total scores during recovery.

Estradiol decreases blood pressure in association with redox regulation in preeclampsia

ABSTRACT In this study, we tested a hypothesis that a short-term estradiol therapy may reduce blood pressure in preeclampsia by modulating plasma oxidative stress. The intramuscular injections of 10 mg 17-beta-estradiol were prescribed to preeclamptic pregnant women during the 3-day therapy before a labor induction. The analyses of mean arterial pressure (MAP), serum estradiol concentrations, plasma superoxide anion (O2.), hydrogen peroxide (H2O2), nitrites (NO2−), and peroxynitrite (ONOO−) were conducted before and during the therapy. We found that the plasma concentrations of oxidative stress markers, such as O2– and H2O2, are higher in preeclampsia and positively correlated with the MAP value. Moreover, it was shown that the plasma concentration of NO2– as an indicator of NO levels is higher in preeclampsia. A short-term intramuscular application of estradiol decreases the MAP value and the plasma concentration of O.–, H2O2, NO2−, and ONOO– in preeclampsia. A positive correlation between the decrease of MAP values and the decrease of plasma concentrations of O2–, H2O2, and ONOO– was found in preeclampsia during a short-term estradiol therapy. We conclude that the short-term estradiol therapy decreases the MAP value in preeclampsia by modulating the plasma oxidative stress. We speculate that the estradiol metabolism in preeclampsia is an important mechanism that contributes to vascular dysfunction.

The Effects of Chronic Administration of Cisplatin on Oxidative Stress in the Isolated Rat Heart

Taken into consideration that molecular and cellular mechanisms involved in cardiotoxicity are still not clear the aim of this study was to compare the production of oxidative stress parameters in the isolated rat heart between animals chronically treated with cisplatin and saline. Th e hearts of male Wistar albino rats (n = 24, 12 per group, age 8 weeks, body mass 250±50 g) were excised and perfused according to the Langendorff technique at gradually increased coronary perfusion pressures (40-120 cmH2O). We followed the production of superoxide anion radicals, hydrogen peroxide, and nitrites and also index of lipid peroxidation during the changes of coronary perfusion pressure (CPP) (from 40 to 120 cm H2O) in coronary venous effl uent. Modifi cations CPP were performed in order to determined if oxidative stress is involved in coronary endothelium response in conditions of hypoxia (lower than 60 cm H2O) and hyperoxia (higher than 80 cm H2O). Based on the results of this research we can conclude that with enhancement of CPP the values of oxidative stress statistically increased. However, this increment is more prominent in control group as a result of preserved endothelium and its more powerful response to hyperoxia. On the other hand, damaged endothelium of cisplatin-treated animals had weaker response to hyperoxia, and also lower antioxidant capacity.

The Influence of Different Types of Physical Activity on The Redox Status of Scuba Divers

Abstract The effect of scuba diving on ROS production and oxidative stress compared to that of other recreational activities is still poorly understood. The aim of this study was to assess the influence of different types of physical activity on the redox status of scuba divers by testing the pro- and anti-oxidative parameters immediately before and after different types of physical load. The prevalence study included 10 professional police divers. All examinees were male, 32 ± 5.1 years of age, well-trained, and with a minimum of five to a maximum of 20 years of diving experience. The study was divided into three experimental protocols: 1) an exercise test (at atmospheric pressure), 2) an at sea dive (30 meters for 30 minutes), and 3) a dive into river current (10 meters for 30 minutes). Immediately before and after the load test of the divers at atmospheric pressure and immediately before and after the dive, blood samples were taken to determine the values of the following pro-oxidant markers: O2−, H2O2, NO2− and TBARS, as well as antioxidant enzymes (SOD and CAT). A comparison of the results before and after physical activity for all three protocols revealed a significant increase in values for NO2−, O2−, H2O2 and CAT after physical activity. It can be concluded that the values of all oxidative stress markers depend on the season of the year in which the research is conducted or on the frequency of dives and degree of physical exertion during this period of the year.

The Effects of Methionine-Enriched and Vitamins (Folate, Pyridoxine and Cobalamine)-Deficient Diet on Exploratory Activity in Rats - A Brief Report

Abstract The aim of this study was to evaluate the impact of increased homocysteine levels induced by methionine nutritional overload (twice as standard) and deficiency of the vitamins folate, pyridoxine and cobalamine, which plays an important role in homocysteine metabolism in anxiety-related behaviour, expressed by means of exploratory activity in rats. Twenty-three male Wistar albino rats (4 weeks old, 100±15 g body weight) were divided into three groups: control (n=8), methionine-enriched (Meth+, 7.7 g of methionine/kg chow, n=7) and methionine-enriched vitamin-deficient (Meth+Vit-, 7.7 g of methionine/ kg chow, deficient in folate, pyridoxine and cobalamine - 0.08, 0.01 and 0.01 mg/kg, n=8). All animals had free access to food and water for 30 days. Behavioural testing was performed using the elevated plus maze (EPM) test. Standard parameters for vertical exploratory activity, the number of rearings and the number of head-dippings, as well as the total exploratory activity (summarizing overall exploratory activity in the EPM) were significantly reduced following 30 days of methionine nutritional overload (p<0.05, p<0.05 and p<0.01, respectively). A methionine-enriched diet coupled with a reduction in some B vitamins resulted in a more pronounced decline in exploratory drive observed in the EPM test compared to the control (p<0.01). The decline in total exploratory activity associated with vitamin deficiency was significant compared to the Meth+ group (p<0.05). The results of this study highlight the important role of homocysteine in the modulation of exploratory activity in rats. Decreased exploratory drive induced by both a methionine-enriched and vitamin-deficient diet could be attributed to an anxiogenic effect of hyperhomocysteinemia.