The significance of blood and salivary oxidative stress markers and chemerin in gestational diabetes mellitus.

OBJECTIVE: Gestational diabetes mellitus (GDM) is a medical complication of pregnancy. The aim of this study was to evaluate the correlations between the salivary and blood levels of oxidative stress markers and an adipokine chemerin, which play a role in the pathogenesis of GDM. MATERIALS AND METHODS: Study groups (Control (n = 29), GDM (n = 22)) had been assessed clinically healthy oral hygiene, according to the age range between 25 and 40 years, BMI<30 kg/m2, who were non-smokers and who were not having systemic diseases. GDM was diagnosed using a 100 g OGTT. Saliva samples were collected without stimulation between 08.30 and 10.00 a.m.. Chemerin and TrxR levels were measured by ELISA. Malondialdehyde, sulfhydryl and NO levels were determined by spectrophotometric analysis. Statistical analysis were performed by Shapiro Wilk, Mann Whitney U, Student's t test. RESULTS: Blood pressure, BMI, and plasma chemerin, salivary chemerin, fasting glucose, LDL, triglyceride, CRP levels in GDM were not different when compared to Control. There were significant differences between Plasma TrxR and HDL levels. Also, significant differences between salivary TrxR and Malondialdehyde levels were observed in GDM. CONCLUSION: It was concluded that the optimal cut-off points for oxidative stress parameters and chemerin level can be used to distinguish between healthy pregnant and GDM.

Toluidine blue O modifies hippocampal amyloid pathology in a transgenic mouse model of Alzheimer's disease.

Recently, we have demonstrated that toluidine blue O (TBO), a phenothiazine dye, shows inhibitory effects on both cholinesterases and amyloid pathology in Alzheimer's disease (AD) cellular model. In the present study, we aimed to determine the effects of TBO (in a purity of 85%) on amyloid and tau pathologies in a triple transgenic mouse model of AD (3xTg-AD). Beginning at 7.5 (mild pathology) or 13 (severe pathology) months of age, 3xTg-AD mice were treated intraperitoneally with 4 mg/kg TBO or vehicle daily for 30 days. TBO treatment significantly reduced the levels of insoluble Aß40 and Aß42 in the hippocampi of mild and severe pathology groups compared to vehicle-treated counterparts. When the levels of full-length amyloid precursor protein (APP) and ß-site APP-cleaving enzyme 1 (BACE1) were assessed in 3xTg-AD mice at late pathological stage, no significant changes were observed after TBO treatment. Similarly, TBO did not recover hyperphosphorylation of tau at residues Thr181 and Ser202/Thr205 significantly in soluble and insoluble hippocampal fractions of 3xTg-AD mice. Taken together, the current study is the first in vivo report, to our knowledge, demonstrating that TBO mitigates amyloid pathology in 3xTg-AD mice with no apparent change on tau phosphorylation. Overall, the preliminary data presented here support the possible use of TBO as a disease-modifying drug for AD treatment.

Effects of phenothiazine-structured compounds on APP processing in Alzheimer's disease cellular model.

The excess accumulation of amyloid-ß (Aß) peptides derived from the sequential cleavage of amyloid precursor protein (APP) by secretases, is one of the toxic key events leading to neuronal loss in Alzheimer's disease (AD). Studies have shown that cholinergic activity may also be involved in the regulation of APP metabolism. In the current study, we have investigated the roles of toluidine blue O (TBO) and thionine (TH), newly recognized phenothiazine-derived cholinesterase inhibitors, on the metabolism of APP in Chinese hamster ovary cells stably expressing human APP751 and presenilin 1 (PS70 cells). We assessed the effects of both compounds on the levels of Aß, soluble APP-α (sAPPα), intracellular APP and ß-site APP-cleaving enzyme 1 (BACE1). After treatment of PS70 cells with TBO or TH without any side effect on cell viability, the levels of secreted Aß40, Aß42 and sAPPα were assayed by specific sandwich ELISAs while APP and BACE1 in cell lysates were analyzed using Western blot. The secreted Aß40, Aß42 and sAPPα in TBO- and TH-treated cells were found to be reduced in a dose-dependent manner compared to vehicle-treated cells. Results suggest that TH mitigated the Aß pathology by lowering APP levels whereas reduced Aß caused by TBO treatment seems to be the outcome of both less substrate availability and amyloidogenic APP processing. Taken together, our results represent the first report demonstrating that TBO and TH can affect amyloid metabolism in vitro.

Age-related changes in the rat brain mitochondrial antioxidative enzyme ratios: modulation by melatonin.

Oxidative stress is an important factor for aging. The antioxidative enzymes glutathione peroxidase (GPx), glutathione reductase (GRd) and superoxide dismutase (SOD) play a crucial role protecting the organism against the age-dependent oxidative stress. Glutathione (GSH) is present in nearly all living cells. GSH is one of the main antioxidants in the cell and it serves several physiological functions. Our purpose was to evaluate the age-related changes in mitochondrial GPx, GRd and SOD activities, and mitochondrial GSH pool in the brains of young (3 months) and aged rats (24 months). We also investigated whether melatonin administration influences these brain mitochondrial enzyme activities and GSH levels in young and aged rats. The results showed that GPx activity increased with age, whereas melatonin treatment decreased GPx activity in the aged rats at levels similar to those in young and young+melatonin groups. The activities of GRd and SOD, however, did not change with age. But, melatonin treatment increased SOD activity in the aged rats. GSH levels, which also increased with age, were not modified by melatonin treatment. The reduction in the SOD/GPx and GR/GPx ratios with age was prevented by melatonin administration. Together, our results suggest that the age-related oxidative stress in rat brain mitochondria is more apparent when the antioxidant enzyme ratios are analyzed instead of their absolute values. The antioxidative effects of melatonin were also supported by the recovery of the enzyme ratios during aging.

Melatonin decreases apoptosis in gastric mucosa during aging.

BACKGROUND AND AIMS: The aging process of tissues is usually accompanied by an increased rate of apoptosis. Although melatonin has been reported to delay aging by scavenging free radicals, its role in the aging of gastric mucosa is not known. In this study, we examined the effects of exogenous melatonin (MLT) on the caspase-dependent apoptosis of gastric mucosa during aging. METHODS: A total of 55 young, middle-aged and aged male Wistar-albino rats were used in this study. The rats were divided into control groups, treated with 0.1 mL of phosphate buffered saline (PBS) containing 1% ethanol, and melatonin groups, treated with MLT (10 mg/kg/day s.c., dissolved in 0.1 mL of PBS containing 1% ethanol) for 21 days. Plasma thiobarbituric acid (TBARS) and sulfhydryl (RSH) levels were studied as oxidant-antioxidant parameters. Caspase-3 activity of the gastric mucosal tissue was assayed as an indicator of apoptosis. The p53 protein level of the gastric mucosa was assayed using a p53 pan ELISA. RESULTS: The plasma TBARS and caspase-3 activity of the gastric mucosa were significantly increased in the aged group. MLT significantly decreased the plasma TBARS levels in all the study groups. MLT also significantly decreased the caspase-3 activity of the gastric mucosa in the aged group (p<0.001). Melatonin had no effect on the p53 expression levels of the gastric mucosa. CONCLUSIONS: In conclusion, our findings suggest that aging gastric mucosa is closely related to a higher apoptosis rate and an increase in caspase- 3 activity. Exogenous MLT might delay aging by decreasing caspase-3 activity.

The role of melatonin on gastric mucosal cell proliferation and telomerase activity in ageing.

Despite antiproliferative effects of melatonin on cultured tumor cells, its effects on normal cells are less clear. The action of melatonin on telomerase activity in ageing of gastric mucosal tissues also is not known. In this study, we investigated the age-related changes in telomerase activity and cellular proliferation rate of gastric mucosa and the effect of melatonin. A total of 37 young (4 months old), and aged (20 months old) Wistar rats, kept under equal periods of light and dark, were divided into control [(PBS), i.p. for 21 days] and melatonin-treated (10 mg/kg melatonin, i.p. for 21 days) groups. Telomerase activity, cell proliferation rate, malondialdehyde (MDA) and glutathione (GSH) levels of the stomach were determined. Melatonin significantly inhibited the gastric mucosal proliferation rate of both young and aged rats. Telomerase activity was significantly reduced in aged rats compared to young animals. Melatonin significantly increased the telomerase activity of both young and aged rats. The MDA levels of gastric mucosa in the aged rats were significantly higher than those of the younger rats. On the contrary, the GSH levels of gastric mucosa of the aged group were significantly lower than that of the young rats. While melatonin had no effect on GSH levels of either young or aged rats, it significantly decreased the MDA levels in aged animals. In conclusion, melatonin may delay the ageing of gastric mucosa by inhibiting the replicative cellular senescence via its stimulatory effect on telomerase activity and suppressive effect on cellular proliferation and lipid peroxidation.

Exogenous melatonin decreases age-induced lipid peroxidation in the brain.

Aging has been proposed as the major risk factor in most neurodegenerative disorders. Oxidative stress is one of the widely accepted hypotheses to explain the pathogenesis of the senescence-related disorders. In this research report we aimed to study the changes in the levels of malondialdehyde as an indicator of lipid peroxidation and glutathione (GSH) of anti-oxidant status during aging. We also studied the effects of exogenous melatonin (MLT) on lipid peroxidation and glutathione levels of different brain regions. A total of forty-seven, 4 (young), 14 (middle-aged) and 20 (aged) months-old male Wistar-albino rats were used in the study. The MDA levels were significantly correlated with increased age (p<0.001). The MDA levels were similar in the different regions of the brain in the younger rats. However, the MDA levels of the cerebellum were significantly lower than that of the frontal and occipital cortex of the aged animals. Exogenous melatonin treatment significantly decreased the MDA levels of all the examined brain regions in the aged groups (p<0.001). The GSH levels of all the examined brain regions were similar in young and middle-aged rats. The GSH levels were inversely correlated with the increasing age. While exogenous melatonin did not have any significant effect on the GSH levels of the different brain regions in the younger rats, it significantly increased in the aged group. Exogenous melatonin can prevent the increased production of age-related lipid peroxidation products and might have a potential role for retardation of age-related oxidative events.

Chemotherapy targeted to cancer tissue potentiates antigen-specific immune response induced by vaccine for in vivo antigen loading and activation of dendritic cells.

Our laboratory has created an Ad-sig-TAA/ecdCD40L vaccine platform designed to activate dendritic cells (DCs). Two subcutaneous (s.c.) injections of the TAA/ecdCD40L protein following the s.c. injection of the Ad-sig-TAA/ecdCD40L vector (TAA/ecdCD40L VPP vaccine) further increases the levels of the tumor-associated antigen (TAA)-specific CD8 effector T cells induced by the vector. We tested the combined effect of chemotherapy-induced destruction of tumor cells and TAA/ecdCD40L VPP vaccine which further increases the levels of TAA available to the DCs at the time of vaccination. The chemotherapy was delivered selectively to the tumor cells using intratumoral (i.t.) injection of the AdCDIRESE1A vector followed by intraperitoneal (i.p.) 5-fluorocytosine (5FC). The 5-fluorouracil (5FU) produced in the vector infected the tumor cells, destroys them and releases the TAA for processing and presentation by the DCs. This mode of delivery spares the TAA CD8 effector T cells from the destructive effect of the 5FU when their proliferation is induced by the vaccine. Test mice treated with both the s.c. administered TAA/ecdCD40L VPP vaccine and the AdCDIRESE1A/5FC chemosensitization vector had the smallest tumor volumes and survived longer than mice treated with either of these agents alone (P < 0.001).

Age-related changes in tissue and plasma zinc levels: modulation by exogenously administered melatonin.

Melatonin (MEL) is synthesized mainly in the pineal gland and derived from 5-hydroxytryptophan (5-HTP). Zinc (Zn) is one of the most important trace elements in the body. Zn and MEL levels are changed with aging. The aim of this study was to investigate the age-related changes of tissue and plasma Zn levels and effect of MEL administration on these parameters. Male wistar rats received for 3 weeks subcutaneous injection of MEL (10 mg/kg). Kidney and pancreas Zn levels in old rats were significantly lower than middle-aged group. Spleen, small intestine, and plasma Zn levels were not different in middle-aged and old rats. On the other hand, MEL treatment increased Zn levels of small intestine and plasma in middle-aged rats. However, kidney, spleen, and pancreas Zn levels were unaffected by MEL treatment.

Antitumor immune response induced by i.t. injection of vector-activated dendritic cells and chemotherapy suppresses metastatic breast cancer.

S.c. injection of the Ad-sig-tumor-associated antigen (TAA)/ecdCD40L vector vaccine has been shown to induce a CD8 immune response against TAA for up to 1 year. The first goal of this article is to test if the injection of autologous dendritic cells infected ex vivo with the Ad-sig-TAA/ecdCD40L can increase the immune response induced against TAA. The second goal is to test the effect of adding local chemotherapy in the form of i.t. injection of the AdCDIRESE1A vector-directed chemotherapy on the immune response induced by i.t. injection of adenoviral vector-activated dendritic cells. The results show that the i.t. injection of the AdCDIRESE1A chemotherapy sensitization vector, which encodes the cytosine deaminase chemotherapy sensitization transcription unit, to the i.t. injection of Ad-sig-ecdCD40L vector-infected dendritic cells increased the level of suppression of the growth of the CCL-51 breast cancer cells. The combination of i.t. injection of the AdCDIRESE1A chemotherapy sensitization vector and Ad-sig-ecdCD40L vector-infected dendritic cells into s.c. CCL-51 breast cancer nodules suppressed the growth of uninjected metastatic tumor nodules in the lung. Finally, adding the i.t. injection of the AdCDIRESE1A chemotherapy sensitization vector to the i.t. administration of dendritic cells infected with a rat HER-2/neu (rH2N)-expressing vector (Ad-sig-rH2N/ecdCD40L) led to the induction of rH2N-specific antitumoral immunity in rH2N transgenic mice (which are anergic to the rH2N antigen). This anti-rH2N immune response suppressed the growth of established H2N-positive NT2 breast cancer more efficiently than did the vector-targeted chemotherapy or Ad-sig-rH2N/ecdCD40L-infected dendritic cell vaccine alone.

The role of transforming growth factor alpha formulation on aspirin-induced ulcer healing and oxidant stress in the gastric mucosa.

PURPOSE: Transforming growth factor (TGF) alpha accelerates wound healing, especially in gastric ulcers. Transforming growth factor alpha can be affected by acid and pepsin in the gastric juice. Oxidative stress also plays a role in the formation of gastric lesions. This study was designed (1) to investigate the effects of microemulsion dosage form on the healing of gastric ulcers, and (2) to determine the relationship between oxidative mechanisms and TGF-alpha during ulcer healing. METHODS: Gastric ulcers were induced in Wistar rats (male, 200 +/- 25 g), by 150 mg/kg acidified aspirin application. The animals were divided into five groups consisting of 7-11 animals. The rats were killed after ulcer induction with aspirin (acute ulcer), or 2 days after ulcer induction (chronic ulcer), or after the daily application of microemulsion and TGF-alpha for 2 days. The ulcer area was measured planimetrically. Thiobarbituric acid reactive substance, glutathione, and gastric mucus levels of tissues were measured by spectrophotometric methods. The total nitric oxide level was measured by a VCl3/Griess assay. Statistical comparisons were made by an analysis of variance and the Mann-Whitney U-test. RESULTS: The ulcer area and malondialdehyde level of gastric tissue both decreased and the glutathione level increased to intact gastric tissue levels, while the mucus and total nitric oxide levels increased significantly after the application of intragastric TGF-alpha. CONCLUSION: These findings suggest that TGF-alpha accelerates the healing process after aspirin-induced gastric injury, and a relationship was observed between this application and the oxidative reactions.

Daily variations of plasma malondialdehyde levels in patients with early breast cancer.

In this study, we aimed to investigate the diurnal variations of malondialdehyde (MDA), in patients with early breast cancer. Ten consecutive premenopausal patients with early stage breast cancer and 10 healthy volunteers were included. Blood samples were taken every 4h for a period of 24h. The peripheral blood cells were counted and the plasma MDA levels measured as an indicator of lipid peroxidation. The daily average MDA levels of the patients were significantly higher than that of the controls (2.7+/-0.2 micromol/ml versus 2.2+/-0.2 micro mol/ml, P=0.044, respectively). The plasma MDA levels of the patients showed significant diurnal variations with the highest levels at 20:00 h and the lowest levels at 04:00 h. In the control group, the plasma MDA levels had no statistically significant diurnal variations. However, the MDA levels at 12:00 and 16:00 h were significantly higher than the levels at 04:00 h. The MDA levels of the patients group were significantly correlated with WBC and neutrophils with a phase difference of 12h (rho=0.341, P=0.012 and rho=0.288, P=0.035, respectively). Though there were weak correlations between the MDA levels and WBC and neutrophils in the control group (rho=0.215, P=0.127 and rho=0.249, P=0.076, respectively), the phase difference was 8h. In conclusion, the current cross-sectional study suggests that the phase differences in daily variations of lipid peroxidation may play a role in carcinogenesis.

The role of epidermal growth factor formulation on stress ulcer healing of the gastric mucosa.

PURPOSE: We investigated the role of epidermal growth factor (EGF) microemulsion (ME) formulation on stress ulcer healing and the levels of gastric mucosal malondialdehyde (MDA) and glutathione (GSH). METHODS: Forty-eight female Wistar rats were divided into five groups according to the treatments given. Ten rats were given intragastric (i.g.) serum physiologic (SP) for 7 days; ten rats were given i.g. ME for 7 days; ten rats were given i.g. EGF in SP 6 microg/kg per day for 7 days; ten rats were given i.g. ME + EGF (Sigma E-7755) 6 microg/kg per day for 7 days; and eight rats were exposed to cold and immobilization stress or no stress (NS), and not given any treatment, as controls. The mean ulcerated area, and the MDA and GSH levels of the gastric mucosa were measured. RESULTS: The mean ulcerated area of the ME+EGF treatment group was significantly less than that of the ME- and EGF-treated groups and the control groups. The gastric MDA levels were also found to be significantly lower in the ME+EGF treated group than in the ME-treated group or the control groups. However, there were no significant changes in the gastric GSH levels among all the groups. The gastric MDA levels were positively correlated with the ulcerated area. CONCLUSION: The ME formulation of EGF at the dose given in this study was more effective than EGF alone on the healing of stress ulceration of the gastric mucosa.

Prognostic role of serum vascular endothelial growth factor, basic fibroblast growth factor and nitric oxide in patients with colorectal carcinoma.

Recently, angiogenesis has gained an increasing interest as a prognostic factor in a variety of solid tumours. In this study we aimed to assess the prognostic role of serum vascular endothelial growth factor (VEGF), basic fibroblast growth factor (b-FGF) and nitric oxide (NO) levels in patients with colorectal carcinoma (CRC).A total of 52 consecutive colorectal cancer patients with stage I to IV disease was included. In addition to routine laboratory and staging procedures, serum VEGF, b-FGF levels, and nitrate levels as a surrogate marker for in-vivo NO production were assayed. Serum VEGF concentrations, adjusted to the platelet count were found to be a significant factor for overall survival in univariate analysis (P=0.033). A new angiogenic index (AI), derived from serum VEGF and nitrate concentrations, was established. AI is the only independent prognostic factor of survival in all patients (P=0.008, Cox regression analysis). Likewise, AI is also significant prognostic factor for disease-free survival (DFS) in patients with operable CRC (P=0.032, Cox regression analysis). In conclusion, serum VEGF and NO levels have prognostic role in patients with CRC and the new angiogenesis index using the serum levels of the factors seem to be useful.