Ihsan Halifeoglu

Antioxidant effects of methionine, α-lipoic acid, N-acetylcysteine and homocysteine on lead-induced oxidative stress to erythrocytes in rats

Lead, widely used in industry, is a great environmental health problem. Many studies have examined its effects on the health of both humans and animals. Experimental studies have shown that sulphur-containing antioxidants have beneficial effects against the detrimental properties of lead. The present study was designed to investigate markers of oxidative stress (hemoglobin (Hb) in whole blood, malondialdehyde (MDA) in sera; superoxidase dismutase (SOD) and glutathione peroxidise (GSH-Px) in erythrocyte hemolysate and vitamins A and E in plasma) in rats given lead (2000ppm) with or without sulphur-containing antioxidants (l-methionine (Met) (100mg/kg/day), N-acetylcysteine (NAC) (800mg/kg/day), l-homocysteine (Hcy) (25mg/kg/day), lipoic acid (LA) (50mg/kg/day)) in their water for 5 weeks. In the lead group, Hb and plasma vitamin E levels were significantly lower whereas MDA levels were significantly higher compared to controls (p<0.05). Hb levels in lead-methionine and lead-LA groups were significantly higher than the lead group (p<0.01). MDA levels were reduced in all groups compared to the lead group (p<0.01). There was a decrease below control values in erythrocyte SOD (p<0.01) and GSH-Px (p<0.05) levels in the lead-LA group. Plasma vitamin A levels were significantly high in lead-methionine group compared to lead group (p<0.01). In conclusion, the data suggests that oxidative stress induced by lead is reduced by sulphur-containing compounds.

Levels of cytokines (IL-1beta, IL-2, IL-6, IL-8, TNF-alpha) and trace elements (Zn, Cu) in breast milk from mothers of preterm and term infants.

It has been well documented that human milk contains several immunomodulator components which are important during infant period when the newborns immune system is still under development. In this study, we aim at examining levels of cytokines, zinc (Zn), and copper (Cu) in milk from mothers of premature and mature infants, and comparing changes during lactation periods consequently. Milk was collected from total of 40 mothers (group M: mothers of mature infants, n = 20; group PM: mothers of premature infants, n = 20) from four lactation stages: colostrum (0–7 days), transitional (7–14 days), mature milk (21 days), and mature milk (2nd month). Levels of cytokines (interleukin [IL]-lβ, IL-2, IL-6, IL-8, tumor necrosis factor-alpha [TNF-α]) were determined by chemiluminesence method, whereas atomic absorption spectrophotometer was used for the determination of Zn and Cu levels. Cytokine levels were determined to be high in colostrum and transient milk from mothers of full-term infants, whereas their levels were reduced drastically in the 21st day and the 2nd month milk (P < .01 , P < .001). Similar trends were observed in milk from mothers of premature infants, but cytokine levels were significantly lower in colostrum compared to colostrum from mothers of mature infants (P < .01). The differences in cytokine levels were continuous in transient milk (P < .05) and mature milk (21 days) (P < .05), whereas there was no statistically significant differences between milk from both groups of mothers in the 2nd month (P > .05). Zn levels in milk from mothers of premature infants were significantly lower compared to the ones from mothers of mature infants (P < .01) and these differences continued through the 2nd month. Although Cu levels were lower in milk from mothers of premature infants, there was no statistically significant difference except colostrum (P > .05). Our results clearly demonstrate that the level of immunomodulating agents such as cytokines and trace elements in milk from mothers of premature infants is less than the level of the same agents in milk from mothers of full-term infants. Although there are commercially available products for infant feeding, human milk is still the best natural nutrient for newborns. Therefore, when premature infants are breastfed, necessary precautions such as supplemantary diets must be considered for possible infections and risks related with immune system deficiency.

A comparison of leptin and ghrelin levels in plasma and saliva of young healthy subjects

In the last 10 years, saliva has been increasingly used as a diagnostic fluid and in predictions of disease progression. Leptin and ghrelin are synthesized in several tissues including the salivary glands. The action of ghrelin is antagonistic to that of leptin. This study was undertaken to measure and compare the saliva ghrelin-leptin and plasma ghrelin-leptin levels in healthy young subjects. In 30 healthy subjects, after an overnight fast, saliva and plasma leptin levels were measured using the ELISA method while saliva and plasma immunoreactive ghrelin levels were measured using a commercial radioimmunoassay (RIA). The latter uses 125I-labeled bioactive ghrelin as a tracer and a rabbit polyclonal antibody raised against full-length octanoylated human ghrelin (Phoenix, Europe, Karlsruhe, Germany). The results of this investigation revealed that saliva leptin levels (6.19+/-2.10 microg/l) were lower than plasma levels (7.39+/-3.23 microg/l) while saliva ghrelin levels (188.5+/-84.7 pg/ml) were higher than plasma levels (126.4+/-38.5 pg/ml), when male and female subjects were considered together. Saliva leptin levels (5.93+/-1.94 microg/l) were lower than plasma levels (6.22+/-2.92 pg/ml) while saliva ghrelin levels (190.3+/-80.2 pg/ml) were higher than plasma levels (120.4+/-35.7 pg/ml) in young males. Saliva leptin levels (6.47+/-2.29 microg/l) were lower than plasma levels (8.73+/-3.14 microg/l) while saliva ghrelin levels (183.2+/-90.2 pg/ml) were higher than plasma levels (129.3+/-42.8 pg/ml) in young females, and both saliva and plasma leptin levels were slightly lower in male subjects in comparison with female subjects. Also, Immunohistochemistry study indicated that ghrelin positivity was found in ductus epithelium of salivary gland. We have demonstrated for the first time that saliva ghrelin levels were higher than in plasma while saliva leptin levels were almost the same as in plasma. Measurements of ghrelin and leptin in saliva is non-invasive, simple, and generally much preferred by patients and thus may be an acceptable alternative to plasma sampling.

Effect of thinner inhalation on lipid peroxidation and some antioxidant enzymes of people working with paint thinner.

Paint thinner is a commonly used industrial solvent with considerable potential for abuse by inhalation. Paint thinner is taken into the body by inhalation or by contact with the skin. Paint thinner is oxidized gradually by cytochrome P450‐dependent monooxygenase and consequently free radicals are produced. In the present study we measured plasma malondialdehyde (MDA, a product of lipid peroxidation) levels as an indicator of oxidative damage and activity levels of antioxidant enzymes gluthatione peroxidase (GSH‐Px) and superoxide dismutase (SOD) in erythrocytes of a group of people (n = 18) working with paint thinner. The control group was composed of 18 healthy adults. There was a statistically significant (p < 0·001) increase in MDA (2·0±0·7 nmol ml‐1) and GSH‐Px (86·5±16·6 U g‐1 Hb) activity levels in people working with paint thinner compared with control subjects (MDA: 1·0±0·3 nmol ml‐1; GSH‐Px: 53·9±14·5 U g‐1 Hb). Similarly, there was also an increase (p < 0·05) in the SOD levels (1079±214·6 U g‐1 Hb) of people working with paint thinner compared with controls (953·3±46·7 U g‐1 Hb). Based on our results, it can be concluded that paint thinner inhalation may increase lipid peroxidation and consequently induce antioxidant enzymes. Copyright

Protective Effect of Melatonin on Antioxidative System in Experimental Ischemia-Reperfusion of Rat Small Intestine

Aims: Effect of exogenously administered melatonin (N-acetyl 5-methoxytryptamine) on antioxidant systems in experimental Ischemia–Reperfusion (I-R) of rat gastrointestinal system (GIS) was examined.Methods: A total of 40 rats were divided into 4 groups: Group 1 (Sham), Group 2 (I-R), Group 3 (I-R + 10 mg/kg melatonin) and Group 4 (I-R + 20 mg/kg melatonin). Activity levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined in small intestines.Results: There was a significant (p<0.05) reduction in GSH-Px levels in Group 2 (64.16±7.02 U/mg protein) compared to Group 1 (80.15±9.32 U/mg protein). We observed a meaningful increase in GSH-Px levels in melatonin applied groups (Group 3: 75.94±9.83 U/mg protein, Group 4: 78.55±9.11 U/mg protein) compared to Group 2. Correspondingly, SOD activity levels were significantly reduced (p<0.001) in Group 2 (24.14±4.35 U/mg protein) compared to controls (52.91±6.13 U/mg protein). A stronger effect (p<0.001) of melatonin was observed on SOD levels compared to GSH-Px levels in both doses (Group 3: 38.96±6.39 U/mg protein, Group 4: 43.07±7.76 U/mg protein). Levels of selenium were reduced significantly in Group 2 (1.11±0.31 μg/g tissue) compared to Group 1 (2.01±0.19 μg/g tissue). Melatonin application in Group 3 (1.13±0.28 μg/g tissue) and Group 4 (1.89±0.48 μg/g tissue) caused an increase in selenium levels. There was a strong correlation between increases in selenium and GSH-Px levels in Group 4 (r:0.651 p<0.01).Conclusions: Melatonin seems to exert its antioxidant effect in GIS tract by stimulating SOD and GSH-Px. Selenium also seems to have an antioxidant contribution on protecting rat gastrointestinal tract I-R injury.

Relationship among levels of leptin and zinc, copper, and zinc/copper ratio in plasma of patients with essential hypertension and healthy normotensive subjects

Obesity is among the main contributing factors in the etiology of essential hypertension (EHT). Leptin, the product of the ob gene, is expressed mainly in adipose tissue. We examined the relationship between two trace elements, zinc (Zn) and copper (Cu), and leptin in patients with EHT (n=35) and normotensive (NT) controls (n=50) because leptin as well as Zn and Cu were reported to be associated with the pathophysiology of EHT. Plasma leptin levels were determined with a commercial enzyme-linked immunosorbent assay (ELISA) kit. Atomic absorption spectrophotometry was utilized to determine plasma Zn and Cu levels. There was a negative correlation between leptin and Zn, and the Zn/Cu ratio (r=−0.359, p<0.05; r=0.361, p<0.05, respectively) in pooled subjects. When subjects were divided based on the presence or absence of hypertension, there was a negative correlation between leptin and Zn (r=−0.375, p<0.05) as well as leptin and Zn/Cu ratio (r=−0.398, p<0.05) in NT subjects. Similar trends were observed when leptin/BMI (body mass index) levels were utilized. There was no significant correlations between levels of Cu and leptin or leptin/BMI. In conclusion, in addition to high leptin levels, Zn and the Zn/Cu ratio were lower in patients with EHT compared to NT controls.

Serum leptin and ghrelin concentrations of maternal serum, arterial and venous cord blood in healthy and preeclamptic pregnant women

Preeclampsia, a common complication of pregnancy, is associated with alteration in the concentration of leptin in maternal blood. The action of leptin is antagonistic to that of ghrelin. Here, we compared the levels of leptin and ghrelin in maternal serum and in arterial and venous cord blood between healthy pregnant women and those suffering from mild and severe preeclampsia. The levels of leptin in maternal and newborn’s blood were elevated in both mild and severe preeclamptic patients (p<0.05). Moreover, serum ghrelin levels were negatively correlated with blood pressure and leptin/ghrelin ratio was decreased in preeclampsia (p<0.05). We concluded that increased production of ghrelin may represent a compensatory hypotensive mechanism in preeclamptic women.ResumenLa preclampsia, una complicación del embarazo, se asocia a alteración de la concentración de leptina en la sangre materna. La acción de la leptina es antagonista de la de la ghrelina. En el presente trabajo, se comparan los niveles de ambas hormonas en suero materno y en sangre arterial y venosa del cordón umbilical en embarazadas normales y en las que sufren preeclampsia leve y severa. Los resultados muestran elevación significativa del nivel de leptina en la sangre materna y fetal en caso de preclampsia, leve y severa. Además, los niveles sérios de ghrelina están negativamente correlacionados con la presión arterial y la relación leptina/ghrelina disminuye significativamente en caso de preclampsia. Es posible que la producción incrementada de ghrelina represente un mecanismo compensatorio hipotensor en mujeres con preeclampsia.

Effects of zinc deficiency and supplementation on plasma leptin levels in rats.

The effects of zinc deficiency and supplementation on plasma leptin levels were studied in Sprague-Dawley rats. After 6 wk on a zinc-deficient diet containing 0.65 ppm Zn/g, the mean body weight was significantly lower than that of normal or zinc-supplemented rats, which showed no difference among them. The plasma leptin and zinc levels were lowest in zinc-deficient animals and highest in those that received a normal diet and daily intraperitioneal injections of 3 mg Zn/kg. These results indicate that zinc deficiency leads to a significant inhibition in plasma leptin levels, whereas zinc supplementation significantly increases plasma leptin.

Comparative Analysis of Plasma Leptin Levels in Both Genders of Patients with Essential Hypertension and Healthy Subjects

While pathogenesis of hypertension is not clearly deciphered yet, increase in body weight, most of the time, is associated with hypertension. There are reports indicating that leptin, product of the Ob gene mainly synhesized in adipocytes, may have role(s) in hypertension, but contribution of the gender is rather contradictive. In the present study, plasma leptin levels in patients of both genders with hypertension and normotensive controls were measured and the relationship between plasma leptin levels and BMI were evaluated in both sexes. Total of 62 patients (31 M/31 F) diagnosed with essential hypertension who were not under any anti‐hypertensive medication were admitted into the study. The control group was composed of 56 (25 M/31 F) age‐, BMI‐ and sex‐matched healthy normotensive volunteers. Plasma leptin levels were determined by a commercial ELISA kit. Plasma leptin and leptin/BMI levels (Mean ± SEM) of women (n:62) were significantly higher than men (n:56) (20.10 ± 1.47 ng/ml versus 4.72 ± 0.50 ng/ml; p < 0.0001). Plasma leptin and leptin/BMI levels of patients of both genders with hypertension were significantly higher than in normotensive subjects (p < 0.05). Leptin and leptin/BMI levels in obese hypertensives were higher than obese normotensives (p < 0.05). Obese hypertensive women had higher leptin and leptin/BMI levels than obese normotensive women (p < 0.05). In conclusion, these results support the hypothesis that a possible link exists between leptin and hypertension. Further studies are needed to clarify how increased levels of leptin affects the pathophysiology of hypertension.

Plasma Trace Elements, Vitamin B12, Folate, and Homocysteine Levels in Cirrhotic Patients Compared to Healthy Controls

Increased serum homocysteine (Hcy) can induce liver diseases and can play a remarkable role in hepatic disorders. The purpose of the present study therefore was to investigate the relationship between serum vitamin B12, folate, zinc and copper, cysteine, and Hcy level differences between cirrhotic patients and healthy subjects. We studied 32 cirrhotic patients (12 females and 20 males) aged 45 ± 11 years and 32 control subjects (12 females and 20 males) aged 39 ± 9 years. There was an inverse correlation between Hcy and vitamin B12 in controls (r = –0.442, p < 0.011) but not in cirrhotic patients (r = –0.147, not significant). Also, mean plasma folate was decreased in cirrhotic patients compared to controls (p < 0.001). Copper increased whereas zinc decreased significantly in cirrhotic patients. A positive correlation was seen between the Cu/Zn ratio and Cu in controls (r = 0.690, p < 0.01), but the correlation between the Cu/Zn ratio and Cu was not significant in the cirrhotic group. Negative correlations were seen between plasma concentration of zinc and the Cu/Zn ratio in controls and cirrhotic patients (r = –0.618, p < 0.01 and r = –0.670, p < 0.01, respectively). Cirrhotic patients displayed multiple abnormalities, including changes in cysteine metabolism and in zinc and copper levels. Although hyperhomocysteinemia is known as an atherogenic and thrombogenic risk factor for cardiovascular disease, it might also be a risk factor for cirrhotic patients. Plasma Hcy, vitamin B12, and folic acid measurement may be useful in the evaluation of cirrhotic patients.