Georgios Papageorgiou

Dietary versus post-mortem use of oregano oil and/or α-tocopherol in turkeys to inhibit development of lipid oxidation in meat during refrigerated storage

The dietary and post-mortem uses of oregano oil in turkeys to inhibit development of lipid oxidation in breast and thigh meat during refrigerated storage were investigated. Using minced meat, patties were prepared from turkey meat post-mortem added with either 200 mg oregano oil or α-tocopherol/kg, meat from turkeys dietary supplemented with either 200 mg oregano oil or α-tocopheryl acetate/kg feed, and control meat. All patties were cooked, placed in a refrigerated cabinet at 4°C, and lipid oxidation was assessed by monitoring malondialdehyde formation after 3, 6 and 9 days of storage. Treatments significantly (P<0.05) retarded lipid oxidation in both breast and thigh meat patties at all storage times compared with controls. The dietary supplementation of either oregano oil or α-tocopheryl acetate exhibited the highest antioxidative activity compared with the other treatments. Post-mortem addition of either oregano oil or α-tocopherol to the minced meat also retarded lipid oxidation in the prepared patties compared with controls; however, this effect was inferior to that of the dietary supplementation even though the post-mortem α-tocopherol supplemented meat contained 90-fold more α-tocopherol than patties from the dietary supplemented meat. Thigh meat was more susceptible to oxidation than breast meat, although the former contained α-tocopherol at markedly higher levels. Supplementing the diet with 200 mg oregano oil/kg, α-tocopherol levels in the breast and thigh meat significantly (P<0.05) increased compared with control. This increase could not be attributed to the α-tocopherol already present in the oregano oil since post-mortem addition of oregano oil to control breast and thigh meat at the same dose could not actually increase the α-tocopherol concentrations.

Intramuscular Administration of Very High Dose of a-Tocopherol Protects Liver from Severe Ischemia/Reperfusion Injury

The effect of intramuscular administration of high (30 mg/kg body weight for 3 days) or very high (300 mg/kg body weight for 3 days) doses of a-tocopherol to Wistar rats subjected to total severe warm hepatic ischemia and reperfusion was investigated. After a 60-minute period of total hepatic ischemia and 120 minutes of reperfusion, animals were killed, and liver samples were taken for determination of malondialdehyde (MDA) and histological examinations. Blood samples were also taken for assay of serum a-tocopherol, alanine transaminase (ALT), aspartate transaminase (AST), and lactic dehydrogenase (LDH). Additional animals were followed for a 7-day survival rate determination. Results showed that ischemia and reperfusion decreased the survival rate to 10%, whereas the levels of AST, ALT, and LDH in serum were increased compared with levels in animals that were sham operated. The MDA concentrations in liver were also increased, from 1.142 to 1.567 nmoles/g, whereas the levels of a-tocopherol in serum were decreased from 10.20 to 1.80 mmol/L. Pretreatment with a-tocopherol increased the viability to 50% and 70%, for the high and very high doses, respectively, and decreased the levels of AST, ALT, and LDH in serum. It also decreased the MDA concentrations in liver to 0.975 and 0.774 nmoles/g for the high and very high doses of a-tocopherol, respectively, whereas it increased the level of a-tocopherol in serum to 11.25 and 13.02 mmol/L for the high and very high doses, respectively. Histological examinations showed protection of the liver parenchyma in the animals treated with a-tocopherol.

Attenuation of intestinal ischemia/reperfusion induced liver and lung injury by intraperitoneal administration of (−)-Epigallocatechin-3-gallate

The aim of this study was to evaluate the effect of ( − )-epigallocatechin-3-gallate (EGCG), a natural antioxidant, on liver and lungs after warm intestinal ischemia/reperfusion (I/R). Thirty male Wistar rats were equally divided into a sham-operation group, an intestinal I/R group and an intestinal I/R group pretreated with EGCG intraperitoneally. Intestinal ischemia was induced by occlusion of the superior mesenteric artery for 60 min followed by reperfusion for 120 min. Immediately after reperfusion, liver, lung and blood samples were collected and analyzed. Results showed that intestinal I/R increased the levels of aspartate (AST) and alanine (ALT) transaminase in serum to 987 and 752 IU/l, respectively. Malondialdehyde (MDA) increased in liver to 1.524 nmol/g in the group subjected to intestinal I/R compared to 0.995 nmol/g in the sham operation group. MDA was also increased in lungs to 1.581 nmol/g compared to 0.896 nmol/g in the sham operation group. Myeloperoxidase (MPO) increased in liver, after intestinal I/R, to 5.16 U/g compared to 1.59 U/g in the sham operation group. MPO was also increased in lungs to 3.89 U/g compared to 1.65 U/g in the sham operation group. Pretreatment with EGCG decreased serum levels of AST and ALT to 236 and 178 IU/l, respectively. It also decreased mean MDA levels in liver and lungs to 1.061 and 1.008 nmol/g, respectively, and mean MPO levels in liver and lungs to 1.88 and 1.71 U/g, respectively. Light microscopy and transmission electron microscopy examinations showed significant alteration in liver and lungs and protection of liver and lung parenchyma in the animals treated with EGCG.

Attenuation of Liver Ischemia/Reperfusion Induced Apoptosis by Epigallocatechin-3-Gallate Via Down-Regulation of NF-κB and c-Jun Expression

INTRODUCTION Hepatic ischemia/reperfusion (I/R) activates Kupffer cells and initiates severe oxidative stress with enhanced production of reactive oxygen species (ROS) and tumor necrosis factor-alpha (TNF-alpha). ROS and TNF-alpha mediate the expression of nuclear factors and kinases, activating the signal transduction pathway, and triggering apoptosis. The aim of our study was to evaluate the potential protective effect of (-)-epigallocatechin-3-gallate (EGCG) administration in inhibition of apoptosis by attenuating the expression of NF-kappaB, c-Jun, and caspase-3 in a model of severe hepatic I/R. MATERIALS AND METHODS Thirty Wistar rats were allocated into three groups. Sham operation, I/R, and I/R-EGCG 50mg/kg. Hepatic ischemia was induced for 60min by Pringles maneuver. Malondialdehyde (MDA), myeloperoxidase (MPO), light histology, scanning electron microscopy, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and immunocytochemistry for NF-kappaB, c-Jun, caspase-3, analysis on liver specimens and aspartate (AST), and alanine (ALT) transferases analysis in serum, were performed 120min after reperfusion. RESULTS Apoptosis as indicated by TUNEL and caspase-3 was widely expressed in the I/R group but very limited in the EGCG treated group. Liver was stained positive for NF-kappaB and c-Jun in the I/R group but failed to be stained positive in the EGCG treated group. MDA, MPO, AST, and ALT showed marked increase in the I/R group and significant decrease in EGCG treated group. Significant alterations of liver specimens were observed by light histology and transmission electron microscopy whilst pretreatment with EGCG resulted in parenchymal preservation. CONCLUSIONS Administration of EGCG is likely to inhibit I/R-induced apoptosis and protect liver by down-regulating NF-kappaB and c-Jun signal transduction pathways.

The incorporation of dehydrated rosemary leaves in the rations of turkeys and their impact on the oxidative stability of the produced raw and cooked meat.

Thirty-six 12-week-old turkeys were distributed into six groups and were raised for 4 weeks on rations containing 0%, 0.5% or 1.0% dehydrated rosemary leaves as antioxidant in the presence of α-tocopheryl acetate from 10 to 300 mg/kg. Following slaughtering, breast and thigh meat samples, raw or cooked, from all six groups were collected to be refrigerated at 4°C for 9 days. All stored samples were submitted to analysis for their concentration in malondialdehyde (MDA), a lipid oxidation marker, and α-tocopherol. The results showed that the rations containing 300 mg/kg α-tocopheryl acetate increased the mean α-tocopherol content of the breast and thigh significantly (P <0.05) compared with the respective control values. No significant (P>0.05) changes could be observed in the α-tocopherol content of breast and thigh of turkeys consuming rations containing up to 1% dehydrated rosemary leaves. The refrigeration of the meats led to spontaneous increase in the MDA content of the breast and thigh meat samples. Samples from turkeys fed rations containing 300 mg/kg α-tocopheryl acetate showed the lowest mean levels of MDA after the 9-day refrigerated period. The incorporation of rosemary in the rations led to a modest decrease in the formation of MDA in the meats compared with the respective mean control values. The combination of α-tocopheryl acetate and rosemary was not associated with an additional decrease in MDA formation.

Inhibition of intestinal ischemia/repurfusion induced apoptosis and necrosis via down-regulation of the NF-kB, c-Jun and caspace-3 expression by epigallocatechin-3-gallate administration

Intestinal ischemia/reperfusion (I/R) produces reactive oxygen species (ROS) activating signal transduction and apoptosis. The aim of this study was to evaluate the effect of (−)-epigallocatechin-3-gallate (EGCG) administration in inhibition of apoptosis by attenuating the expression of NF-kB, c-Jun and caspace-3 in intestinal I/R. Thirty male wistar rats were used. Group A sham operation, B I/R, C I/R-EGCG 50 mg/kg ip. Intestinal ischemia was induced for 60 min by clamping the superior mesenteric artery. Malondialdehyde (MDA), myeloperoxidase (MPO), light histology, Fragment End Labelling of DNA (TUNEL), immunocytochemistry for NF-kB, c-Jun and caspace-3 analysis in intestinal specimens were performed 120 min after reperfusion. Apoptosis as indicated by TUNEL and Caspace-3, NF-kB and c-Jun was widely expressed in I/R group but only slightly expressed in EGCG treated groups. MDA and MPO showed a marked increase in the I/R group and a significant decrease in the EGCG treated group. Light histology showed preservation of architecture in the EGCG treated group. In conclusion, EGCG pre-treatment is likely to inhibit intestinal I/R-induced apoptosis by down-regulating the expression of NF-kB, c-Jun and caspase-3.

Effect of olive leaf (Olea europea L.) extracts on protein and lipid oxidation in cooked pork meat patties enriched with n-3 fatty acids

BACKGROUND The effect of olive leaf extracts on lipid and protein oxidation of cooked pork patties refrigerated stored for 9 days was evaluated. Patties were prepared from longissimus dorsi muscle of pigs, and dietary supplemented with linseed oil. RESULTS Results showed that dietary linseed oil modified the fatty acid composition of pork patties by increasing (P ≤ 0.05) n-3 (α-linolenic acid) and decreasing (P ≤ 0.05) n-6 (linoleic acid) fatty acids. Olive leaf extracts at supplementation levels of 200 and, especially, of 300 mg gallic acid equivalents kg⁻¹ meat, delayed lipid oxidation by reducing (P ≤ 0.05) both primary (conjugated dienes and hydroperoxides) and secondary (malondialdehyde) oxidation products. They also inhibited protein oxidation in a concentration-dependent manner by reducing (P ≤ 0.05) protein carbonyls and increasing (P ≤ 0.05) protein sulfhydryls. In addition, they improved sensory attributes of the n-3 enriched patties. CONCLUSION Results suggested that olive leaf extracts might be useful to the meat industry as an efficient alternative to synthetic antioxidants.

Severe total hepatic ischemia and reperfusion: Relationship between very high α-tocopherol uptake and lipid peroxidation

Reperfusion injury of the liver occurs in liver transplantation and in major hepatectomies. It triggers a severe oxidative stress that leads to increased lipid peroxidation. In our study we examined the effect of parenteral supranutritional administration of α-tocopherol, a vitamin that plays a key role in the endogenous antioxidant system, to rats subjected to severe ischemia/reperfusion (I/R) injury of the liver. α-Tocopherol was administered to the animals at doses of 30 and 300mg/kg bw, whereas total hepatic ischemia was induced for 60 min followed by 120 min reperfusion. Tissue and blood samples were collected for malonyldialdehyde (MDA) and serum α-tocopherol assay, respectively. In the sham operation group, mean MDA level in liver was 1.14nmole/g wet tissue in the control subgroup, and 1.01 or 0.74nmole/g wet tissue in the subgroups given 30 or 300mg/kg α-tocopherol. In the I/R group, mean MDA level was 1.57nmole/g wet tissue in the control subgroup, and 0.97 and 0.77nmole/g wet tissue in the subgroups given 30 or 300mg/kg α-tocopherol. Mean levels of α-tocopherol in serum (μmole/l) were 10.20 and 1.80 in the control subgroups, 25.28 and 11.25 in the subgroups treated with 30 and 300mg/kg bw of α-tocopherol, and 31.00 and 13.02 in the subgroups treated with 30 and 300mg/kg bw of α-tocopherol, within the sham-operation and I/R groups, respectively. A significant decrease of MDA accompanied by a significant increase of serum α-tocopherol was documented in the α-tocopherol-treated rats within both groups. Ischemia/reperfusion triggered a significant increase of the MDA level in the liver of the rats not treated with α-tocopherol as compares with the treated animals.

Lipid Profile, Low-Density Lipoprotein Oxidation and Ceruloplasmin in the Progeny of Families With a Positive History of Cardiovascular Diseases and/or Hyperlipidemia

Fifty-eight healthy progeny (mean age ± SD 13.9 ± 7.9 years) of 39 families with a positive history for Cardiovascular Diseases ([CVD] n = 44) or hyperlipidemia (n = 14) were included in the study and were compared with 30 age-matched control participants, with a negative family history, to evaluate lipid profile, ceruloplasmin (Cp), and lipid peroxidation product (malondialdehyde [MDA]) levels, as well as in vitro copper-induced Low-density lipoprotein (LDL) oxidizability. Mean serum levels of total cholesterol, LDL cholesterol (LDL-C), apolipoprotein B-100, and MDA of the participants were significantly higher than those of the controls. Lag time, an LDL resistance oxidation marker, was lower in the study group and negatively correlated with LDL-C (r = -.437, P < .05) and Cp (r = -.272, P < .05) serum levels. In conclusion, progeny with a positive family history for CVD or hyperlipidemia have an atherogenic lipid profile and increased LDL susceptibility to oxidation. High Cp levels seem to be related to lower resistance of LDL to oxidation.

The protective effect of oxygenated perfluorocarbons (PFCs) on intestinal ischemia reperfusion injury (I/R) in rabbits.

Objective: To evaluate the effect of intraluminal administration of oxygenated perfluorocarbons (PFCs) on small intestine’s viability in an experimental model of acute ischemia-reperfusion (I/R). Methods: Twenty rabbits were divided in four groups: sham-operated controls (group A), acute I/R (group B), acute I/R plus infusion of PFCs 30 min before ischemia (group C), and acute I/R plus infusion of PFCs 30 min before reperfusion (group D). Malondialdehyde (MDA) tissue levels and d-lactate blood samples were taken. All tissue sections were examined under light microscope. Results: Mean MDA levels in group A: 1.79 ± 0.97 at 0 min, 2.25 ± 1.76 at 120 min and 3.70 ± 1.76 nmols/g at 180 min. Group B: 2.60 ± 0.58 at 0 min, 4.20 ± 0.58 at 120 min and 5.48 ± 2.01 at 180 min. Group C: 1.54 ± 0.85 at 0 min, 1.14 ± 0.37 at 120 min and 0.59 ± 0.35 at 180 min. Group D: 2.12 ± 0.62 at 0 min, 3.97 ± 0.70 at 120 min and 2.32 ± 0.37 at 180 min (p < 0.05). Mean d-lactate levels in group A: at 0 min 36.45 ± 1.99, at 120 min 39.10 ± 2.37 and at 180 min 40.05 ± 2.13 mg/dl. Group B: 61.23 ± 11.03 at 0 min, 74.84 ± 10.70 at 120 min and 89.90 ± 9.29 at 180 min. Group C: at 0 min 51.05 ± 10.36, at 120 min 56.07 ± 11.27 and at 180 min 57.20 ± 11.19. Group D: 64.36 ± 5.26 at 0 min, 72.55 ± 7.19 at 120 min and 77.02 ± 9.41 at 180 min (p < 0.05). Histopathological analysis indicated a significant improvement in the groups of oxygenated PFCs compared with I/R group. Conclusion: Intraluminal administration of oxygenated PFCs seems that protect the intestine from the I/R injury.