The effect of carnosine pretreatment on oxidative stress and hepatotoxicity in binge ethanol administered rats

Carnosine is a dipeptide having strong antioxidant effects. Oxidative stress plays an important role in pathogenesis of alcohol-induced liver injury. In this study, we investigated the effect of carnosine pretreatment on ethanol-induced oxidative stress and hepatotoxicity. Rats were given carnosine (2 g/L in drinking water) for 4 weeks and then ethanol was administered orally to rats at a dose of 5 g/kg every 12 hours for 3 doses totally (binge model). All rats were killed 6 hours after last ethanol injection. Plasma alanine (ALT) and aspartate (AST) transaminase activities and liver triglyceride, malondialdehyde (MDA), diene conjugate (DC), glutathione (GSH), vitamin E and vitamin C levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione transferase (GST) activities were determined. Binge ethanol administration resulted in significant increases in plasma transaminase activities, hepatic triglyceride and lipid peroxide levels. However, GSH, vitamin E, vitamin C levels and GSH-Px and GST activities were found to be decreased following ethanol administration. Macromicrovesicular steatosis was also seen. Carnosine pretreatment appeared to prevent the increase of plasma ALT and AST activities and hepatic MDA and DC levels following ethanol treatment. In addition, hepatic GSH levels increased, but there were no changes in triglyceride, vitamin E, vitamin C levels and SOD, GSH-Px and GST activities, following ethanol treatment in carnosine-pretreated rats. There was also no change in liver histopathological appearance. In conclusion, carnosine prevented the increases in serum transaminase activities and lipid peroxides in liver of ethanol-treated rats, without any change on steatosis in liver.

The combinations of TNFalpha-308 and IL-6 -174 or IL-10 -1082 genes polymorphisms suggest an association with susceptibility to sporadic late-onset Alzheimer's disease

OBJECTIVE

Single nucleotide polymorphisms in the regulatory regions of the cytokine genes for tumor necrosis factor alpha (TNFalpha), interleukin (IL)-6 and IL-10 have been suggested to influence the risk of Alzheimer's disease (AD) with conflicting results.

AIM

To investigate the TNFalpha-308, IL-6 -174 and IL-10 -1082 gene polymorphisms as susceptibility factors for AD.

METHODS

We analyzed genotype and allele distributions of these polymorphisms in 101 sporadic AD patients and 138 healthy controls.

RESULTS

Heterozygotes (AG) or combined genotype (AG+AA) for IL-10 -1082 were associated with approximately two-fold increase in the risk of AD. Carriers of A alleles of both TNFalpha-308 and IL-10 -1082 had 6.5 times higher risk for AD in comparison with non-carriers. Concomitant presence of both mutant TNFalpha-308 A and IL-6 -174 C alleles raised three-fold the AD risk, whereas there was no notable risk for AD afflicted by IL-6 -174 polymorphism alone.

CONCLUSION

Our results suggest that TNFalpha and IL-10 promoter polymorphism might be a risk factor for AD. The combined effects of TNFalpha-308, IL-6 -174 and IL-10 -1082 variant alleles may be more decisive to induce functional differences and modify the risk for AD.

COX-2 expression and clinical outcome in early-stage breast cancer patients treated with adjuvant chemotherapy: A prospective study

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Background: To evaluate the association of cox-2 expression with the outcome after adjuvant chemotherapy in patients with early breast cancer. Methods: This was planned as a prospective study recruiting consecutive patients receiving adjuvant anthracycline based chemotherapy and with available tissue blocks permitting all immunohistochemical analyses. Cox-2 expression, in addition to other classical biological factors, was evaluated with immunohistochemistry. Disease and patient related, and biological predictors of both overall survival (OAS) and relapse free survival (RFS) were analyzed by Cox regression analysis. Median and mean survival times were calculated according to the Kaplan Meier method. Results: A total of 88 patients were recruited over a period of 24 months. Median age was 45 (29 to 70), and 60% of subjects were premenapausal. Median tumour diameter and number of axillary lymph nodes involved were 2 cm (1 to 6 cm), and 2 (0 to 15), respectively. Median follow up is 74.2 months. Univariate analysis revealed menopausal status and estrogen receptor expression as predictors of OAS, and menopausal status as the correlate of RFS. Multivariate analysis confirmed the independent predictive value of both menopausal status and estrogen receptor expression for OAS (P=0.009, HR=4.18, and P=0.014, HR=0.20, respectively). No multivariate analysis could be performed for RFS. Cox-2 expression was not associated with OAS or RFS (P=0.208, HR=1.92, and P=0.132, HR=1.89, respectively). Interestingly, Cox-2 expression was correlated with Estrogen receptor (ER) and Progesteron receptor (PR) expression (P=0.006, R=-0.303, and P=0.004, R=-0.312, respectively). Conclusions: Cox-2 expression fails to predict clinical outcome of early breast cancer patients treated with adjuvant chemotherapy. However, Cox-2 expression seems to negatively correlate with ER and PR expression. It should be tested in this patient population whether Cox-2 may play a part in hormonal resistance.

No significant financial relationships to disclose.

Impressive survival data with semimetronomic oral chemotherapy with old agents in heavily treated metastatic breast cancer patients

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Background: To assess the efficacy of semi-metronomic regimen metronomic cyclophosphomide with oral etoposide in heavily treated patients with metastatic breast cancer. Methods: Consecutive metastatic breast cancer (MBC) patients predominantly refractory to antracyclines, taxanes, and antimetabolites receiving semi-metronomic regimen of metronomic cyclophosphomide with oral etoposide were evaluated for clinical efficacy and toxicity. This novel regimen comprised of continuous oral cyclophosphomide 50 mg/day, and oral etoposide given as 2 x 50 mg/day for 5 days. Results: A total of 42 MBC patients received this treatment in 2.5 years (May 2005-October 2008). The median age was 51.5 (29–81), ER and/or PR receptor status was positive in 67%, and c-erb-B2 overexpression existed in 50%. The biologically favorable group, hormone responsive and c-erb-B2 negative comprised of 36% of cases. The portions of patients with visceral metastases, cranial metastases, and 2 or more organ involvement were 82%, 24%, and 65%, respectively. Subjects had received this treatment in the fourth or more advanced setting in 50% of cases (after a median of 2.5 cycles). The median overall and progression free survival figures were 25 and 10.5 months, respectively. No toxic mortality occurred, and the treatment was well tolerated. Toxicity and response data are being updated currently. Conclusions: Semi-metronomic treatment with metronomic cyclophosphomide and oral etoposide is a novel and effective strategy in heavily pretreated MBC patients. Survival data and low cost may make this regimen a highly preferable option in this difficult patient group.

No significant financial relationships to disclose.

High-dose chemotherapy and stem cell support in the management of metastatic germ cell cancer: A quantitative review

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Background: To analyze the independent associates of outcome in metastatic germ cell cancer (MGCC) patients treated with high dose chemotherapy (HDC) and stem cell rescue. Methods: Thirty-two published patient cohorts with MGCC (encompassing 2176 patients; 510 patients treated upfront and 1666 at relapse) were identified from PUBMED and Cochrane Registry of Clinical Trials. Weighed Regression Analyses of these trials were conducted to define prognosticators. Results: Correlate of overall survival (OAS) and survival with no evidence of disease (NED) in upfront HDC trials was number of chemotherapeutics in HDC (OAS with 2 agents: 60% vs. 3 or more agents: 72%, p = 0.047, survival with NED with 2 agents: 47% vs. 3 or more agents: 64%, p = 0.009). In trials of HDC at relapse, independent associates of OAS with multivariate analysis were line of chemotherapy index, an indicator of line of chemotherapy utilization (p = 0.004), and median age (≤30: 42%, >30: 49%, p = 0.023), whereas independent correlates of better survival with NED were again number of chemotherapeutics in HDC (2 agents: 54% vs. 3 or more agents: 33%, p = 0.001), and seminoma fraction (seminoma fraction ≤9%: 28% vs. seminoma fraction >9%: 49%, p < 0.001 ). Toxic mortality of HDC regimens employed in these trials ranged between 0% and 17%. Conclusions: HDC can cure patients with MGCC both as initial or salvage therapies. However, this study shows that type and setting of HDC, as well as patient age, and seminoma fraction all appear to be linked with benefit from HDC in MGCC. Future trials should continue to address the usage of tandem HDC cycles with multiagent protocols in high risk patients with MGCC.

No significant financial relationships to disclose.

Effect of taurine on oxidative stress and apoptosis-related protein expression in trinitrobenzene sulphonic acid-induced colitis

Ulcerative colitis (UC) is a multi-factorial inflammatory disease of the colon and rectum. The present study was undertaken to investigate the effect of taurine, an anti-oxidant amino acid, on oxidative stress and the expression of apoptosis-related proteins, pro-apoptotic Bax and anti-apoptotic B cell lymphoma-2 (Bcl-2) in colon tissue in rats with 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis. Rats received taurine (1.5% w/v) in drinking water for 15 days before and 15 days after administration of TNBS solution. Then, colonic myeloperoxidase (MPO) activity, malondialdehyde (MDA) and glutathione (GSH) levels, and Bax and Bcl-2 expression were measured. TNBS-induced colitis caused significantly increased MPO activity and MDA levels and decreased GSH levels in colon tissue compared to controls. Increase in Bax expression and decrease in Bcl-2 expression were detected in colon of rats with TNBS-induced colitis. Taurine treatment was associated with amelioration in macroscopic and microscopic colitis scores, decreased colonic MPO activity and MDA levels and increased GSH levels in TNBS-induced colitis. In addition, taurine reduced the expression of Bax and prevented the loss of Bcl-2 proteins in colon tissue of rats with TNBS-induced colitis. The results of this study show that taurine administration may exert beneficial effects in UC by decreasing inflammatory reactions, oxidative stress and apoptosis.

The Arg194Trp polymorphism in DNA repair gene XRCC1 and the risk for sporadic late-onset Alzheimer's disease

Alzheimer's disease (AD) is defined pathologically by the presence of beta-amyloid plaques, neurofibrillary tangles and extensive neuronal loss. Evidence indicates that increased DNA damage may contribute to neuronal loss in AD. Recently, it has been shown that in AD neurons have a reduced capacity for some types of DNA repair. Polymorphisms in DNA repair genes may be associated with differences in repair efficiency of DNA damage. Variants of several DNA repair genes, including the base excision repair gene XRCC1, have been described previously. We hypothesised that Arg194Trp polymorphism of XRCC1 gene may contribute to genetic susceptibility for AD. In order to test this hypothesis, we investigated Arg194Trp polymorphism at the XRCC1 gene in the DNA samples of 98 patients with AD and 95 healthy subjects. The frequency of the Trp allele was more pronounced among cases (11.2%) compared with controls (5.8%). On combining the homozygous and heterozygous variants of each codon, the variants seemed to be at twofold risk of AD, although the risk estimates were not statistically significant (OR=1.95, 95% CI 0.88-4.34, p=0.09). In addition, the 194Trp allele revealed a borderline significance (OR=2.05, 95% CI 0.96-4.37, p=0.056). According to our results, it may be speculated that the polymorphic variants of XRCC1 codon 194 have a role in the development of AD.

Hypoglycemia due to ectopic release of insulin from a paraganglioma

Insulin-secreting pancreatic tumors and insulin-like growth hormone-secreting non-islet cell tumors can cause hypoglycemia. However, insulin-releasing paraganglioma or pheochromocytoma has almost never been reported. A 67-year-old female patient was admitted to our hospital because of headache, palpitation, perspiration, faintness, frequent sense of hunger and absent-mindedness. These intermittent symptoms had begun approximately a year before admission. On physical examination, she had high blood pressure of 150/90 mm Hg. Hormonal studies demonstrated increased urinary norepinephrine levels, and hyperinsulinemic hypoglycemia was confirmed while the patient was symptomatic. Abdominal MRI revealed a retroperitoneal mass measuring 4.5 cm in the pancreatic region. She was treated with an alpha-blocking agent to control blood pressure preceding the removal of the mass. Histopathological diagnosis was paraganglioma, and immunohistochemically insulin staining in the neoplastic cells was demonstrated. Her blood pressure normalized and hypoglycemia relieved after the operation. The patient did not have recurrence of hypoglycemia after a year of follow-up. Paraganglioma is a rare tumor of the neural crest, and co-secretion of insulin and catecholamines has been reported only by a single case report in the literature. The present patient is another case with this co-secretion.

Decreases in taurine levels induced by beta-alanine treatment did not affect the susceptibility of tissues to lipid peroxidation

We aimed to investigate the effect of decreased taurine levels on endogenous and induced lipid peroxide levels in liver, brain, heart and erythrocytes as well as prooxidant and antioxidant balance in the liver of rats administered beta-alanine (3%, w/v) in drinking water for 1 month to decrease taurine levels of tissues. This treatment caused significant decreases in taurine levels of liver (86%), brain (36%) and heart (15%). We found that endogenous and ascorbic acid-, NADPH- and cumene hydroperoxide-induced malondialdehyde (MDA) levels did not change in the liver, brain and heart homogenates following beta-alanine treatment. Also, H(2)O(2)-induced MDA levels remained unchanged in erythrocytes. In addition, we did not observe any changes in levels of MDA, diene conjugates, glutathione, alpha-tocopherol, ascorbic acid and the activities of superoxide dismutase, glutathione peroxidase and glutathione transferase in the liver. According to this, buffering or sequestering capacity of tissues to exogenous stimuli was not influenced by reduced taurine levels in tissues of rats.

Betaine or taurine administration prevents fibrosis and lipid peroxidation induced by rat liver by ethanol plus carbon tetrachloride intoxication

The aim of this study was to investigate the effect of betaine or taurine on liver fibrogenesis and lipid peroxidation in rats. Fibrosis was induced by treatment of rats with drinking water containing 5% ethanol and CCl(4) (2 x weekly, 0.2 ml/kg, i.p.) for 4 weeks. Ethanol plus CCl(4) treatment caused increased lipid peroxidation and disturbed antioxidant system in the liver. Histopathological findings suggested that the development of liver fibrosis was prevented in rats treated with betaine or taurine (1% v/v in drinking water) together with ethanol plus CCl(4) for 4 weeks. When hepatic taurine content was depleted with beta-alanine (3% v/v in drinking water), portal-central fibrosis induced by ethanol + CCl(4) treatment was observed to proceed cirrhotic structure. Betaine or taurine was also found to decrease serum transaminase activities and hepatic lipid peroxidation without any change in hepatic antioxidant system in rats with hepatic fibrosis. In conclusion, the administration of betaine or taurine prevented the development of liver fibrosis probably associated with decreased oxidative stress.

Serum pro-oxidant-antioxidant balance and low-density lipoprotein oxidation in healthy subjects with different cholesterol levels

In this study, we investigated serum pro-oxidantantioxidant balance in 210 healthy subjects divided into groups with low and high atherogenic risk according to the levels of serum total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein- cholesterol (HDL-C). Diene conjugate (DC), malondialdehyde (MDA), polyunsaturated fatty acid (PUFA), vitamin E, and vitamin C levels and antioxidant activity (AOA) were determined in the serum. Endogenous DC and copper-induced MDA levels were also measured in the LDL fraction isolated by precipitation with buffered heparin from plasma in 80 healthy subjects with different serum LDL-C levels. Subjects with a high atherogenic risk had significantly higher plasma DC, MDA, and PUFA levels, but lower vitamin E/TC values and AOA than subjects with low atherogenic risk. Endogenous DC and copper-induced MDA levels in the LDL fraction were increased in subjects with serum LDL-C levels higher than 4.14 mM compared with those with normal LDL-C levels. In conclusion, this study clearly indicates that a disturbance in serum pro-oxidant-antioxidant balance and an increase in LDL oxidation are concomitant with higher TC and LDL-C and lower HDL-C levels in the serum.

Increased lipid peroxidation in the liver and kidney and their mitochondrial fractions following buthionine sulfoximine induced glutathione depletion in guinea pigs

Malondialdehyde (MDA) and diene conjugates (DC) and vitamin C levels and the activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were determined in the liver and kidney and their mitochondrial fractions of guinea pigs 48 h after the injection of L-buthionine-(S,R)-sulfoximine (BSO), a glutathione (GSH) depleting agent. In BSO-induced GSH depletion, lipid peroxidation and SOD activities were found to be increased but GSH-Px activities did not change in the liver and kidney and their mitochondrial fractions. In addition, vitamin C levels remained unchanged in the liver and kidney homogenates. These results indicate that GSH depletion may influence oxidative stress in the liver and kidney and their mitochondrial fractions of guinea pigs.

An increase in lipoprotein oxidation and endogenous lipid peroxides in serum of obese women

Endogenous malondialdehyde and diene conjugate levels, the susceptibility of apolipoprotein B-containing lipoproteins to copper-induced lipid peroxidation, and antibody titer against oxidized low-density lipoproteins were increased, but serum antioxidant activity was unchanged in obese women. Serum cholesterol, low-density lipoproteincholesterol, and trigliceride levels were also elevated, but high-density lipoprotein-cholesterol levels remained unchanged in obese women. In vitro, oxidation of apolipoprotein B-containing lipoproteins and levels of antibody against oxidized low-density lipoprotein correlated with body mass index, serum total cholesterol, and low-density lipoproteincholesterol levels in obese women. These results indicate that obesity is associated with increases in endogenous lipid peroxides, oxidation of low-density lipoproteins, and lipids in serum.

Aminoguanidine, an inducible nitric oxide synthase inhibitor, plus N-acetylcysteine treatment reduce the lipopolysaccharide-augmented hepatotoxicity in rats with cirrhosis

Hepatic cirrhosis is produced in rats by administration of thioacetamide (TAA) (0.3 g/L tap water for a period of three months). This treatment caused an increase in oxidative stress in the liver. Lipopolysaccharide (LPS) administration (5 mg/kg) to rats with cirrhosis was observed to increase hepatotoxicity as well as oxidative stress according to biochemical and histopathological findings. However, aminoguanidine (AG), an inducible nitric oxide synthase (iNOS) inhibitor, plus N-acetylcysteine (NAC) treatment reduced the LPS-augmented hepatotoxicity in rats with cirrhosis without making any changes in oxidative stress in the liver.

Glutathione S-transferase-pi in malignant tissues and plasma of human colorectal and gastric cancers

PURPOSE

In this study, 16 paired samples of colorectal and gastric cancers and adjacent non-neoplastic tissues were analysed for the determination of glutathione S-transferase (GST) activities and the expression of GST-pi.

METHODS

Western blotting procedure as well as plasma GST-pi levels were used.

RESULTS

GST activities were found to be increased in malignant tissues of patient compared with adjacent normal tissues. A significant correlation was detected between GST activity and GST-pi expression in malignant tissues of patients. Plasma GST-pi levels increased in patients compared to aged-matched control subjects. When the patients were grouped according to TNM stage, GST-pi expression in malignant tissues as well as plasma GST-pi levels were higher in patients with more advanced tumor stages.

CONCLUSIONS

Our results indicate that GST-pi expression in malignant tissues and plasma GST-pi levels in human colorectal and gastric cancers increased depending on the stages of tumor.

Taurine has a protective effect against thioacetamide-induced liver cirrhosis by decreasing oxidative stress

Thioacetamide (TAA) administration (0.3 g/l of tap water for a period of 3 months) to rats resulted in hepatic cirrhosis as assessed by biochemical and histopathological findings. This treatment caused an increase in the levels of malondialdehyde (MDA) and diene conjugates (DCs) and a decrease in the levels of glutathione (GSH), vitamin E, vitamin C and the activities of glutathione peroxidase (GSH-Px) in the liver of rats. Superoxide dismutase (SOD) activities were unchanged. Taurine (2% w/w, added to the chow diet) was administered together with TAA (0.3 g/l of drinking water) for 3 months. Taurine was found to decrease TAA-induced hepatic lipid peroxidation and to increase TAA-depleted vitamin E levels and GSH-Px activities. Histopathological findings also suggested that taurine has an inhibitive effect on TAA-induced hepatic cirrhosis. These results indicate that taurine treatment has a protective effect against TAA-induced liver cirrhosis by decreasing oxidative stress.

The protective effect of taurine against thioacetamide hepatotoxicity of rats

Thioacetamide (TAA) administration (three consecutive intraperitoneal injections of 400 mg/kg at 24-h interval) to rats resulted in hepatic injury as assessed by the measurement of serum transaminase activities and histopathological findings. This treatment caused an increase in the levels of malondialdehyde (MDA), diene conjugates (DCs) and glutathione (GSH) and the activity of superoxide dismutase SOD ), and a decrease in the levels of vitamins E and C and the activity of glutathione peroxidase (GSH-Px) in the liver of rats. Taurine administration (400 mg/kg, i.p., every 12 h and started 24 h prior to the first TAA injection) was found to decrease serum transaminase activities and hepatic lipid peroxidation without any significant change in hepatic antioxidant system. Histopathological findings also suggested that taurine has ameliorated effect on TAA-induced hepatic necrosis. These results indicate that taurine treatment, together with TAA administration, diminished the severity of the liver injury by decreasing oxidative stress due to its possible scavenger effect.

Mitochondrial lipid peroxides and antioxidant enzymes in colorectal adenocarcinoma tissues

Lipid peroxide levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione transferase (GST) activities were investigated in mitochondrial fractions obtained from tumorous and nontumorous colorectal tissues of fourteen patients with colon and rectum cancer. Histopathological evaluations, including type, stage, necrosis and lymphocyte infiltration were also performed for each patient. The activities of SOD, GSH-Px and GST were increased significantly, but lipid peroxide levels remained unchanged in mitochondria obtained from tumors compared to adjacent normal tissues of subjects with colorectal cancer. When the patients were grouped according to their histopathological evaluation, such as type, stage, necrosis and lymphocyte infiltration, no relationship was observed between the histopathological results and the mitochondrial lipid peroxidation or antioxidant enzyme activities.

Imbalance between lipid peroxidation and antioxidant status in preeclampsia

Lipid peroxidation and the antioxidant system were investigated in the plasma and placenta of normal and preeclamptic pregnant women. A significant increase in thiobarbituric acid reactive substance (TBARS), significant decreases in total thiol (t-SH) content and superoxide dismutase (SOD) activity, and unchanged vitamin C levels and glutathione peroxidase (GPx) activity were observed in the plasma of preeclamptic women compared to women with normal pregnancies. In placentas from preeclamptic women TBARS levels were significantly elevated, while glutathione and vitamin C levels and GPx, glutathione S-transferase and SOD activities were decreased. After delivery, the elevated TBARS values decreased significantly and the reduced SOD activity and t-SH contents increased significantly. We concluded that preeclampsia is associated with an imbalance between lipid peroxides and the antioxidant system.