Comparison of Intermittent Fasting Versus Caloric Restriction in Obese Subjects: A Two Year Follow-Up.

OBJECTIVE: Caloric restriction (CR) is proven to be effective in increasing life span and it is well known that, nutritional habits, sleeping pattern and meal frequency have profound effects on human health. In Ramadan some Muslims fast during the day-light hours for a month, providing us a unique model of intermittent fasting (IF) in humans. In the present study, we have investigated the effects of IF versus CR on the same non-diabetic obese subjects who were followed for two years according to the growth hormone (GH)/Insulin like growth factor (IGF)-1 axis and insulin resistance. DESIGN: Single-arm Interventional Human Study. PARTICIPANTS: 23 female subjects (Body Mass Index (BMI) 29-39, aged between 28-42years). SETTING: Follow-up is designed as 12 months of CR, after which there was a month of IF and 11 months of CR again, to be totally 24 months. Subjects' daily diets were aligned as low calorie diet during CR and during the IF period, the same subjects fasted for 15 hours in a day for a month and there was no daily calorie restriction. Nutritional pattern was changed as 1 meal in the evening and a late supper before sleeping and no eating and drinking during the day light hours in the IF model. Subjects made brisk walking twice a day during the whole follow-up including both CR and IF periods. BMI, Blood glucose, insulin, TSH, GH, HbA1c, IGF-1, Homa-IR and urinary acetoacetate levels were monitored once in three months and twice in the fasting month. MEASUREMENTS AND RESULTS: While subjects lost 1250 ± 372g monthly during the CR, in the IF period, weight loss was decreased to 473 ± 146 g. BMI of all subjects decreased gradually and as the BMI decreased, glucose, HbA1c, insulin, Homa-IR and TSH levels were decreased. GH levels were at baseline at the beginning, increased in the first six months and stayed steady during the CR and IF period than began decreasing after the IF period, while IGF-I increased gradually during the CR period and beginning with the 7th day of IF period, it decreased and kept on decreasing till the end of the follow-up. Urinary acetoacetate levels were higher during the IF period suggesting a constant lipid catabolism. CONCLUSION: Our results suggest that, CR affects metabolic parameters positively which will help especially pre-diabetic and insulin resistant patients without any pharmacological approach. In addition IF without calorie restriction can enhance health and cellular resistance to disease without losing weight and those effects may be attributed to different signalling pathways and circulating ketones during IF. Changes observed during IF are probably due to the changes in eating and sleeping pattern and thus changes in metabolic rhythm.

Epidermal growth factor increases tissue antioxidant enzyme activities in ethanol-induced gastric injury in rat.

The aim of the present study is to investigate whether the antioxidant mechanisms are involved in epidermal growth factor (EGF)-mediated protection from ethanol-induced gastric damage. Twenty four female Sprague-Dawley rats were assigned into 3 groups; control (C) group (n=8) was given physiologic saline by gavage; ethanol (E) group (n=8) was given 1 ml of 80% ethanol (v/v) in distilled water by gavage and EGF group (n=8) was given EGF (100 mg/kg-body wt.) intraperitonealy half an hour before the administration of ethanol. The protein carbonyl content was significantly higher in the E group than the C group (p<0.01). On the other hand, EGF decreased the protein carbonyl content in the EGF group (p<0.01). Gastric myeloperoxidase activity increased significantly after the administration of ethanol (p<0.01). The administration of EGF decreased significantly the myeloperoxidase activity (p<0.01). Although ethanol caused a slight decrease in the catalase activity, no statistical significance was observed between groups E and C. The catalase activity increased significantly after EGF treatment (p<0.01). The superoxide dismutase activity decreased significantly in the E group when compared to the C group (p<0.05) while it was found to be increased significantly in the EGF group in comparison with the E group (p<0.01). In summary, the present results indicate that the gastroprotective effect of EGF in the experimental lesions induced by ethanol could be attributed to its property such as to augment the antioxidant enzyme activities.

The oxidative effect of prolonged CO2 pneumoperitoneum on renal tissue of rats.

BACKGROUND: Despite its advantages, laparoscopic donor nephrectomy is associated with prolonged operation time, which could potentially increase oxidative stress in the graft. We performed the first experimental, randomized, controlled study with blind assessment of outcome to address this possibility. METHODS: Wistar-Albino rats were randomized into three groups. The animals in the control group were subjected to a sham operation under anesthesia; the animals in the other two groups were subjected to CO(2) pneumoperitoneum (Pp) for 120 and 240 min, respectively. The kidneys were removed at the end of each experiment. The concentrations of protein carbonyl and sulfhydryl (SH) groups and the activities of superoxide dismutase (SOD) were measured in renal tissue samples as markers of oxidative stress. Renal tissue samples were also evaluated histopathologically using light microscopy. RESULTS: Exposure to 120 min of Pp significantly increased the finding of oxidative stress in renal tissue samples, with an increase in protein carbonyl content and a decrease in protein sulfhydryls and tissue (SOD) activities. When exposure to Pp was prolonged from 120 min to 240 min, Pp associated oxidative stress was found to be increased. These changes occurred in the absence of light microscopical evidence of overt tissue damage. CONCLUSIONS: In an experimental model resembling laparoscopic donor nephrectomy, we found that exposure of pneumoperitoneum prolonged from 120 min to 240 min acts as an additive factor with respect to causing increased oxidative stress in renal tissue. Because these effects imply subtle tissue injury that may contribute to the chronic demise of renal grafts obtained laparoscopically, avoiding the use of Pp if possible and keeping operation time less than 120 min during laparoscopic donor nephrectomy appear to be advisable.

The effect of different intraabdominal pressures on lipid peroxidation and protein oxidation status during laparoscopic cholecystectomy.

BACKGROUND: This prospective, randomized, and controlled study was designed to investigate the effects of different intraabdominal pressures (IAPs) on lipid peroxidation and protein oxidation status during laparoscopic cholecystectomy (LC). METHODS: Twenty-four patients (12 men, 12 women) who underwent LC at either 10 or 15 mmHg of IAP were randomized into two groups. Repeated blood samples were collected to measure thiobarbituric acid reactive substances (TBARS) levels to assess lipid peroxidation and protein carbonyl content and protein sulfhydryl groups to assess protein oxidation status. RESULTS: Serum protein carbonyls and TBARS levels were found to be increased immediately after desufflation in both study groups when compared to the preoperative levels. On the other hand, protein sulfhydryl levels were found to be decreased in both study groups. Although increases in protein carbonyls and TBARS levels were more prominent in patients who underwent LC at 15 mmHg of IAP, this difference was not statistically significant between both groups. CONCLUSIONS: The results suggest that both 15 and 10 mmHg of LAP could lead to an increased oxidative stress response during LC, but no difference was found between the groups.

A comparison of the oxidative stress response and antioxidant capacity of open and laparoscopic hernia repairs.

BACKGROUND: Free radical-induced lipid peroxidation that is associated with a decrease in the antioxidant status of plasma occurs in many kinds of surgical procedures. In this study, we aimed to investigate markers of oxidative stress--malondialdehyde (as thiobarbituric acid reactive substances), protein carbonyls, and protein sulfhydryls--in patients undergoing Lichtenstein tension-free hernioplasty (LH) or laparoscopic preperitoneal hernia (LPPH) repair. METHODS: Seventeen patients with unilateral inguinal hernia and no complications or recurrence were included in this study. Ten were randomized to undergo LH and seven to LPPH repair. Heparinized blood samples were taken to measure the levels of oxidative stress markers in the patients undergoing hernia repair. Levels of malondialdehyde, protein carbonyls, and protein sulfhydryls were measured preoperatively and at 6 and 24 hours postoperatively in all patients. RESULTS: Both types of hernia repair caused a significant increase in the oxidative stress response and a decrease in antioxidant activity. Plasma levels of malondialdehyde and carbonyls (indicators of oxidant activity) were significantly higher in the LH than in the LPPH repair group (P<.05), and plasma sulfhydryl levels (indicators of antioxidant activity) were significantly lower in the LH than in the LPPH group (P<.05). In both groups, significant differences were also found between the preoperative levels and the postoperative levels 6 and 24 hours (P<.05). CONCLUSIONS: These data demonstrate that both LH and LPPH repair cause a significant increase in markers of oxidative stress; however, the oxidative stress response associated with LH is greater than that associated with LPPH repair.

Can preconditioning reduce laparoscopy-induced tissue injury?

BACKGROUND: Pneumoperitoneum (P) created to facilitate laparoscopy (L) is associated with splanchnic perfusion, ischemia/reperfusion (I/R) injury, and oxidative stress. In this randomized controlled experimental study with blind outcome assessment, we evaluated the effect of preconditioning (PRE) on L-induced I/R injury. METHODS: The subjects were 40 Sprague-Dawley male rats. P was created in all except controls, using carbondioxide (CO2) insufflation under a pressure of 15 mmHg. PRE consisted of 10 min of P, followed by 10 min of deflation (D). The rats were randomized to the following groups: Group P was subjected to 60 min of P. Group P/D was subjected to 60 min of P, followed by 45 min of D. Group PRE/P was subjected to PRE, followed by 60 min of P. Group PRE/P/D was subjected to PRE, followed by 60 min of P and 45 min of D. Group C (control) was subjected to a sham operation, without P. Its anesthesia time was equal to that for group PRE/P/D. At the end of the experiments, the rats were killed; blood, liver, and kidney samples were then obtained and coded. Plasma alanine aminotransferase (ALT) and malondialdehyde (MDA), as well as homogenized tissue MDA levels and glutathione (GSH) activities, were measured; tissue samples were assessed for histopathological evidence of injury; all assessments were done by investigators blinded to the study design. The results were decoded and analyzed statistically with the Kruskal-Wallis and Mann Whitney tests. A p <0.05 was considered significant. RESULTS: Plasma ALT as well as plasma, liver, and kidney MDA levels and liver and kidney injury scores were increased, whereas liver and kidney GSH values were decreased in groups P and P/D, as compared to group C. Rats subjected to PRE before P had plasma ALT, kidney MDA, and kidney and liver GSH levels comparable to controls; their kidney and liver injury scores were higher than controls but significantly lower than nonpreconditioned animals. PRE enabled decreased plasma, kidney, and liver MDA as well as increased kidney GSH if applied before P; its efficacy on oxidative stress was limited to providing decreased kidney MDA and increased kidney GSH if applied before P/D. However, PRE significantly attenuated kidney and liver injury after P as well as P/D. CONCLUSION: PRE consisting of 10 min of P followed by 10 min of D decreases the oxidative stress induced by sustained P in the plasma, liver, and kidney. PRE significantly limits liver and kidney injury after prolonged P and P/D. After further studies to define its ideal timing, PRE before L incorporating P may have clinical relevance, especially for elderly patients or those with impaired hepatic and/or renal function or perfusion.

Biochemical evidence of crossed cerebellar diaschisis in terms of nitric oxide indicators and lipid peroxidation products in rats during focal cerebral ischemia.

OBJECTIVES: Cerebral hypoperfusion in the contralateral cerebellar hemisphere after stroke is interpreted as a functional and metabolic depression, possibly caused by a loss of excitatory afferent inputs on the corticopontocerebellar pathway terminating in the cerebellar gray matter. This phenomenon is defined as crossed cerebellar diaschisis and can be diagnosed clinically by positron emission tomography, single-photon emission computed tomography, brain magnetic resonance imaging and electroencephalography in terms of regional cerebral blood flow or metabolic rate of oxygen measurements. MATERIALS AND METHODS: In the present study, nitric oxide indicators (nitrite and cyclic guanosine monophosphate) and lipid peroxidation products (malondialdehyde and conjugated dienes) were measured in rat cerebral cortices and cerebella after permanent right middle cerebral artery occlusion in order to assess the crossed cerebellar diaschisis. RESULTS: Nitrite values in ipsilateral cortex were significantly higher than those in contralateral cortex at 10 (P < 0.001) and 60 (P < 0.05) min of ischemia but no significant changes were observed in both cerebellum compared to the 0 min values. In both cerebral cortex and cerebellum cGMP levels at 10 and 60 min were significantly increased (P < 0.001). This increase was marked in ipsilateral cortex and contralateral cerebellum when compared with opposite cortex and cerebellum (P < 0.001). MDA values in ipsilateral cortex were significantly higher than those in contralateral cortex at 60 min of ischemia (P < 0.05). Contralateral cerebellar MDA values were found significantly higher than those in ipsilateral cerebellum at 0 (P<0.001) and 60 (P < 0.05) min of ischemia. In ipsilateral cortex, conjugated diene values at 0, 10, 60 min of ischemia were higher than those in contralateral cortex. On the other hand 0, 10, 60 min conjugated diene levels in contralateral cerebellum were significantly higher than those in ipsilateral cerebellum (P < 0.001). CONCLUSION: These findings support the interruption of the corticopontocerebellar tract as the mechanism of the crossed cerebellar diaschisis.

The effect of melatonin on lipid peroxidation during radiotherapy in female rats.

BACKGROUND: Because radiotherapy is one of the causes of primary or secondary ovarian failure, protection of ovarian functions in the patients receiving total body or pelvic radiotherapy is of importance. In this study, we investigated the role of melatonin in the oxidative damage in both whole body and ovaries, which is caused by radiotherapy. MATERIALS AND METHODS: Eighteen female rats were divided into 3 groups, each of which consisted of 6 rats. First group was control group receiving no treatment, second group received total body radiotherapy (RT) by 2 x 360 cGy only and third group received radiotherapy plus melatonin. Malondialdehyde (MDA) levels in both blood and ovarian tissue were detected as the indicator of free radical (FR) damage. Levels of erythrocyte superoxide dismutase (SOD) and glutathion peroxidase (GPX) in blood were measured as the indicators of antioxidant level. RESULTS: Radiotherapy caused a significant increase in the levels of MDA in blood and ovarian tissue (p < 0.001). However, MDA levels decreased in the radiotherapy plus melatonin group (p < 0.05). SOD and GPX levels decreased insignificantly in the radiotherapy only group while they increased in the radiotherapy plus melatonin group significantly (p < 0.01 and p < 0.05, respectively). CONCLUSION: Melatonin, in rats, reduced the level of MDA, which is elevated by radiotherapy and increased the levels of SOD and GPX, which are involved in the antioxidant system.

Effects of Lamotrigine on brain nitrite and cGMP levels during focal cerebral ischemia in rats.

Glutamate receptor antagonists are protective in animal models of focal cerebral ischemia. Lamotrigine (3,5-diamino-6-[2,3-dichlorophenyl]-1,2, 4-triazine) is an anticonvulsant drug that blocks voltage-gated sodium channels and inhibits the ischemia-induced release of glutamate. Experiments in primary neuronal cultures implicate nitric oxide (NO) as a mediator of glutamatergic neurotoxicity acting via N-Methyl-D-Aspartate (NMDA) receptors. The effect of glutamate release inhibitor, Lamotrigine upon NO and cGMP production has been examined in focal cerebral ischemia in rats. Focal cerebral ischemia was produced by the permanent occlusion of right middle cerebral artery (MCA) in urethane anesthetized rats. A number of indicators of brain NO production (nitrite, cGMP) were determined in ipsilateral and contralateral cerebral cortex and cerebellum after 0, 10, 60 min of focal cerebral ischemia. The same parameters were measured in rats treated with Lamotrigine (20 mg/kg, i.p.) 30 min before or just after the occlusion of the right MCA.

A chemiluminescence assay detecting the antioxidative effects of glutathione and uric acid on erythrocytes and hemolysates exposed to t-butyl hydroperoxide.

The aim of this study was to compare the antioxidative effects of glutathione (GSH) and uric acid (UA) on erythrocytes and hemolysates exposed to t-butyl hydroperoxide, by using a chemiluminescence (CL) technique. CL formation was induced by t-butyl hydroperoxide in an experimental system consisting of erythrocytes and hemolysates in Tris-HCl buffer (pH 7.4). GSH or UA was added as an antioxidant. In erythrocytes, 10 microM and 50 microM concentrations of either GSH or UA reduced the maximum chemiluminescence values (MCVs) significantly when compared to those of controls. In erythrocytes, MCVs observed in the 50 microM GSH group were significantly lower than those of the 50 microM UA group. In hemolysates, while 10 microM concentration of GSH or UA did not alter MCVs, 50 microM concentration of either GSH or UA reduced MCVs. The reduction of MCVs observed in the 50 microM GSH group was greater than that of the 50 microM UA group. When the effects of equimolar concentrations of GSH or UA on erythrocytes and hemolysates were compared, the MCVs of hemolysates were lower than those of erythrocytes. These results can be attributed to the fact that antioxidant agents react much more easily in the hemolysate medium.

The effects of nitric oxide synthase inhibitor, L-NAME on NO production during focal cerebral ischemia in rats: could L-NAME be the future treatment of sudden deafness?

Recent evidence in primary neuronal cell culture implicates NO as a mediator of glutamatergic neurotoxicity acting via N-methyl-D-aspartate (NMDA) receptors. In this study, we investigated the effects of inhibition of NOsynthase activity in focal cerebral ischemia in rats. Focal cerebral ischemia was produced by permanent occlusion of right MCA in urethane anesthetized rats. A number of indicators of brain NO production, nitrite and cGMP were determined in ipsilateral and contralateral cerebral cortex and cerebellum after 0, 10 and 60 minutes of focal cerebral ischemia. The same parameters were measured in rats pre- and posttreated with the potent Nitric oxide synthase (NOS) inhibitor, NW-nitro-L-arginine methyl ester (L-NAME).

Inhibitory role of N omega-nitro-L-arginine methyl ester (L-NAME), a potent nitric oxide synthase inhibitor, on brain malondialdehyde and conjugated diene levels during focal cerebral ischemia in rats.

The effect of N omega-nitro-L-arginine methyl ester (L-NAME) on ischemic neuronal damage was studied in a rat model of permanent focal cerebral ischemia in terms of ipsilateral and contralateral cortical and cerebellar tissue lipid peroxides. Forty-five male Swiss Albino rats were assigned to one of four groups; sham operated as control, subjected to right middle cerebral artery occlusion or injection of L-NAME (10 mg/kg i.p.) either 30 min before or just after right middle cerebral artery occlusion. Changes in lipid peroxides were expressed as nanomoles of malondialdehyde and conjugated diene per milligram of protein. Malondialdehyde values following 60 min of ischemia relative to contralateral cortex and conjugated diene levels in 0, 10 and 60 min of ischemia were found to be higher in ipsilateral cortex than in contralateral cortex. On the other hand, contralateral cerebellar malondialdehyde levels after 0 and 60 min of ischemia and conjugated diene levels after 0, 10 and 60 min of ischemia were higher than those in ipsilateral cerebellum. Pharmacological inhibition of nitric oxide synthase by L-NAME before or just after permanent middle cerebral artery occlusion significantly decreased the malondialdehyde and conjugated diene levels in both the cortex and the cerebellum. No significant differences were found in malondialdehyde values between rats that had been pre- and post-treated with L-NAME, but conjugated diene levels in the post-treated group seemed to be significantly lower than those in the pretreated group. On the whole, these results suggest that malondialdehyde and conjugated diene represent early biochemical markers of lipid peroxidation in ischemic tissues, reflecting the radical-mediated tissue damage.

The effects of detergents on t-butyl hydroperoxide-induced chemiluminescence.

We examined the effects of Triton X-100, digitonin, sodium dodecyl sulfate, taurocholic acid, and cetylpyridinium chloride on hemoglobin-catalyzed and t-butyl hydroperoxide-induced chemiluminescence. The experimental system contained hemoglobin, luminol, t-butyl hydroperoxide, and different concentrations of detergents (5-100 mg/dl) in TRIS-HCl buffer. Control assays were performed by excluding detergents. Chemiluminescence was detected using a liquid scintillation counter in single photon mode. All concentrations chosen for each detergent reduced the maximum chemiluminescence value and retarded the time that maximum chemiluminescence occurred. The most prominent reduction in maximum chemiluminescence was observed with 50 and 100 mg/dl digitonin. The smallest reduction was observed with 5 mg/dl sodium dodecyl sulfate, without retardation of the time that maximum chemiluminescence occurred. Our aim was to use detergents in membrane-containing experimental systems and hence to identify the detergent with the least effect on chemiluminescence. Our results suggest that sodium dodecyl sulfate is the most suitable detergent for chemiluminescence studies in membrane systems.