Basu Dev Banerjee

Oxidative stress in term small for gestational age neonates born to undernourished mothers: a case control study

BackgroundThe objective of this study was to assess the status of oxidative stress in term small for gestational age (SGA) newborn infants born to undernourished mothers by estimating levels of erythrocyte superoxide dismutase (SOD), catalase, reduced glutathione, and serum malondialdehyde (MDA) in cord blood and comparing them to healthy appropriate for gestational age (AGA) controls. This was done in a case control design at a tertiary level teaching hospital.MethodsWe included 20 singleton healthy SGA newborn infants born between 38–40 weeks to undernourished mothers with a) post-pregnancy weight < 50 kg or height < 145 cm AND b) hemoglobin < 8.0 g/dL or serum albumin < 2.5 g/dL. An equal number of age and sex matched AGA newborn infants born to healthy mothers served as Controls. Mothers with other risk factors and newborns with complications during delivery or immediate newborn period were excluded. MDA, SOD, catalase and reduced glutathione were measured in the cord blood of all neonates and compared between the groups (unpaired t test); levels were also correlated to maternal weight, height, hemoglobin, and albumin by both univariate (pearsonian correlation) and multivariate (multiple regression) analysis.ResultsThe activity of MDA was increased (5.33 ± 0.72 vs 2.55 ± 0.22 nmol/mL; P < 0.0001) while levels of superoxide dismutase (493.6 ± 54.9 vs. 786.8 ± 79.1 U/g Hb; P < 0.0001), catalase (1.48 ± 0.24 vs. 2.31 ± 0.20 U/g Hb; P < 0.0001) and reduced glutathione (2.84 ± 0.37 vs 6.42 ± 0.23 Umol/g Hb, P < 0.0001) were decreased in term SGA born to undernourished mothers as compared to term AGA born to healthy mothers. On univariate analysis, all the markers of oxidative stress correlated significantly with maternal parameters (P < 0.005). On multivariate analysis, maternal albumin and hemoglobin accounted for maximum correlation with the markers of oxidative stress.ConclusionsIntrauterine malnutrition is associated with significant oxidative stress in small for gestational age neonates born at term to malnourished mothers.

Taurine Prevents Tamoxifen-Induced Mitochondrial Oxidative Damage in Mice

Tamoxifen is a selective oestrogen receptor modulator widely used in the treatment of breast cancer. Tamoxifen potentially affects mitochondrial functions as it acts as an uncoupling agent and a powerful inhibitor of mitochondrial electron transport chain. There is concern for the deleterious effects of tamoxifen. Taurine is known to have membrane stabilizing and antioxidant properties. We studied effect of taurine pre-treatment on the toxicity of tamoxifen in mouse liver mitochondria focusing specifically on the redox cycle biomarkers. Tamoxifen caused a significant rise in the mitochondrial lipid peroxidation, protein carbonyl content and superoxide radical generation. There was a significant change in the mitochondrial thiol profile in the tamoxifen-treated animals. Pre-treatment of mice with taurine (100 mg/kg) markedly lowered mitochondrial lipid peroxidation, protein carbonyl content and superoxide radical generation. It also restored decreased enzymatic and non-enzymatic antioxidants of mitochondria. It is suggested that taurine has a potential role in ameliorating tamoxifen-induced mitochondrial toxicity, and the protection is afforded either by reversing the decline of antioxidants or by the direct free radical-scavenging activity.

Organochlorine pesticide residues in maternal blood, cord blood, placenta, and breastmilk and their relation to birth size

There is a growing concern that persistent organic pollutants like organochlorine pesticides (OCPs) can impair fetal growth and affect birth size. However, currently available epidemiological evidence is inconclusive. In this case-control study, we examined the association between exposure to hexachlorocyclohexane (HCH) and its isomers (α-HCH, β-HCH and γ-HCH), dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) and birth size. We recruited 60 infant-mother pairs, comprising of 30 term, small for gestational age babies with their mothers (Case group), and another 30 term, appropriate for gestational age babies with their mothers (Control group). This study was conducted in a tertiary hospital in Delhi, India, between March, 2009 and February 2010. Organochlorine pesticides were estimated in maternal blood, cord blood, placenta and breastmilk samples, using gas-liquid chromatography. Transplacental and transmammary transfer of OCPs was assessed by correlating the maternal blood OCP levels with those in cord blood and breastmilk by simple linear regression. The birthweight, crown heel length, head circumference, mid-arm circumference and ponderal index of the neonates was correlated with OCP levels in the maternal blood, cord blood, placenta and breastmilk. The OCP estimates were compared between samples of the case and control group. There was a significant (P<0.001) transplacental transfer of all OCPs, however the transmammary transfer was insignificant for most OCPs except α-HCH. The OCP levels in the case group were higher than the control group; these were significantly more for t-HCH in cord blood and breastmilk; β-HCH in maternal blood, cord blood and breastmilk; DDE in placenta and DDT in breastmilk. There was a significant negative correlation between birthweight and t-HCH levels in maternal blood (P=0.022), cord blood (P<0.001), placenta (P=0.008) and breastmilk (P=0.005); β-HCH in cord blood (P<0.001) and placenta (P=0.020); γ-HCH in placenta (P=0.045); and DDT (P=0.009). Length at birth had a significant negative correlation with t-HCH in cord blood (P=0.014) and breastmilk (P<0.001); β-HCH in cord blood (P=0.016) and breastmilk (P=0.012); DDE in placenta (P=0.016); and DDT in breastmilk (P=0.006). Similarly, OCP levels were also found to be negatively correlated with head circumference, ponderal index and chest circumference in neonates. We conclude that prenatal exposure to some OCPs could impair the anthropometric development of the fetus, reducing the birthweight, length, head circumference, chest circumference and ponderal index.

Possible involvement of free radicals in the differential neurobehavioral responses to stress in male and female rats

The effect of restraint stress (RS) on neurobehavioral and brain oxidative stress parameters, and their modulation by antioxidants were evaluated in male and cycling female rats. Exposure to RS suppressed both open arm entries and open arm time in the elevated plus maze and these changes were more marked in males than in females. Assay of brain homogenates revealed that the behavioral suppression was associated with similar differential increases in malondialdehye (MDA) and decreases in glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) levels in males and females. Pretreatment with alpha-tocopherol (25 and 50 mg/kg) and N-acetylcysteine (100 and 200 mg/kg), attenuated the stress induced alteration of behavioral and oxidative stress markers in a consistent manner in both male and female rats. These findings suggest that males may be more susceptible than females to stress induced neurobehavioral changes and free radicals may exert a regulatory influence in such gender dependent responses to stress.

Protective effect of lipoic acid against methotrexate-induced oxidative stress in liver mitochondria

Methotrexate (MTX) is a folic acid antagonist widely used as a cytotoxic chemotherapeutic agent for leukemia and other malignancies. The purpose of this study was to investigate the damage caused by MTX on liver mitochondria and its protection by using antioxidant properties of lipoic acid. MTX substantially affects mitochondrial function by reducing glutathione levels leading to disturbances in antioxidant enzyme defense system. Lipoic acid occurs naturally in mitochondria as a coenzyme. In various studies lipoic acid has been convincingly shown to exhibit an antioxidant role when supplemented exogenously. We studied the effect of lipoic acid pre-treatment on the toxicity of MTX in mouse liver mitochondria focusing specifically on the oxidative stress. MTX caused a significant rise in the mitochondrial lipid peroxidation (LPO), protein carbonyl (PC) content and superoxide radical generation. It also affected the mitochondrial thiol profile. Pre-treatment of mice with lipoic acid (35 mg/kg) markedly lowered mitochondrial LPO, PC content and superoxide radical generation. It also restored decreased enzymatic and non-enzymatic antioxidants of mitochondria. It is suggested that lipoic acid has a potential role in suppressing MTX-induced mitochondrial toxicity, and it affords protection either by reversing the decline of antioxidants or by the directly scavenging the free radicals.

DNA damage and cholinesterase activity in occupational workers exposed to pesticides

The present study was designed to evaluate genotoxicity, acetyl cholinesterase (AChE) activity, hepatic and renal toxicity in occupational workers exposed to mixture of pesticides (n=70) with same number of healthy subjects as controls. The mean comet tail DNA % (TD %) and tail moment (TM) were used to measure DNA damage, while AChE activity and other biochemical parameters such as markers of nephrotoxicity (urea and creatinine) and hepatotoxicity (AST, ALT and ALP) were measured as biomarkers for toxicity due to exposure of pesticides. The occupational workers were continuously exposed to mixture of pirimiphos methyl, chlorpyrifos, temephos and malathion on a regular interval as per usage and activity. The comet assay using lymphocytes of exposed workers showed significantly higher TD percentage value (60.43% vs. 31.86%, p<0.001) and TM value (14.48 μm vs. 6.42 μm, p<0.001) in occupational workers as compared to controls. AChE activity in erythrocytes was found to be decreased (3.45 KAU/L vs. 9.55 KAU/L in controls, p<0.001) and associated with the duration of exposure to pesticides used by the workers. Enzyme levels for hepatic and renal functions were also found significantly different in occupational workers than healthy controls (p<0.001). These results suggest that the exposure to mixture of pirimiphos methyl, chlorpyrifos, temephos and malathion may induce DNA damage, decrease in AChE activity, hepatotoxicity as well as nephrotoxicity. Periodic biomonitoring of these biomarkers along with imparting education and training to occupational workers for safe application of pesticides is recommended for its potential hazards.

Relationship of possible stress-related biochemical markers to oxidative/antioxidative status in obsessive-compulsive disorder.

Free radicals have been found to play an important role in obsessive-compulsive disorder (OCD). So, we measured the oxidative/antioxidative status of OCD patients, and assessed its use as a biological marker. The study was carried out on 20 healthy and 20 OCD subjects, aged between 20 and 40 years. Biochemical parameters of all subjects were assessed and compared. A significant difference in superoxide dismutase (SOD) levels was observed between the OCD and control groups (p < 0.05); malondialdehyde (MDA) levels were also significantly higher in OCD subjects (p < 0.05). Our study found an overall oxidative imbalance in OCD, leaning towards the antioxidant side in sufferers (specifically towards SOD). SOD has a protective role in overcoming oxidative stress; therefore, oxidative stress could have a pathophysiological role in OCD. Therapy specifically targeting MDA production will have a beneficial effect in overcoming the oxidative stress, anxiety and affective disorder which may be associated with OCD.

Advanced glycation end products enhance reactive oxygen and nitrogen species generation in neutrophils in vitro

Increased oxidative stress (OS) in diabetes mellitus is one of the major factors leading to diabetic pathology. However, the mediators and mechanism that provoke OS in diabetes is not fully understood, and it is possible that accumulation of advanced glycation end products (AGEs) formed secondary to hyperglycemic conditions may incite circulating polymorphonuclear neutrophils (PMN) to generate reactive oxygen species (ROS). In this report, we aim to investigate the effect of AGE on reactive oxygen and nitrogen species generation and subsequent OS in PMN. AGE-HSA exert dose- and time-dependent enhancement of ROS and reactive nitrogen intermediates (RNI) generation by PMN. Increased ROS and RNI generation were found to be mediated through the upregulation of NADPH oxidase and inducible nitric oxide synthase (iNOS), respectively, as evident from the fact that AGE-treated neutrophils failed to generate ROS and RNI in presence of diphenyleneiodonium, a flavoprotein inhibitor for both enzymes. Further increased generation of ROS and RNI ceased when the cells were incubated with anti-RAGE antibody suggesting the involvement of AGE–RAGE interaction. Also increased malondialdehyde (MDA) and protein carbonyl formation in AGE-exposed PMN suggest induction of OS by AGE. This study provides evidence that AGEs may play a key role in the induction of oxidative stress through the augmentation of PMN-mediated ROS and RNI generation and this may be in part responsible for development of AGE-induced diabetic pathology.

Association of glutathione S-transferase M1 and T1 gene polymorphism with oxidative stress in diabetic and nondiabetic chronic kidney disease

Background and Objective: Glutathione S-transferases (GSTs) belong to a family of ubiquitous and multifunctional enzymes that work as one of the endogenous antioxidants in our body. This study was designed to look into the association of GST polymorphism with oxidative stress in both diabetic and nondiabetic chronic kidney disease (CKD). Design and Methods: Three groups of patients (50 in each): diabetics without CKD (DM), diabetic CKD (DM-CKD), and nondiabetic CKD (NDM-CKD) and 50 age- and sex-matched healthy controls were recruited. Genotyping was done for GSTM1 and GSTT1 genes using a multiplex polymerase chain reaction. Serum GST and malondialdehyde (MDA) as a marker of oxidative stress were measured spectrophotometrically. Results: Based on genotyping, subjects were categorized as GSTM1+/GSTT1+, GSTM1−/GSTT1+, GSTM1+/GSTT1−, and GSTM1−/GSTT1−. Serum GST levels were lower among subjects with deletion in one/both GST genes, whereas MDA levels were found to be correspondingly raised. A negative correlation for MDA versus GST levels was observed among genotypes with one/both gene deletions. Presence of GSTM1+/GSTT1− and GSTM1−/GSTT1− was significantly higher among patients with CKD in both diabetics and nondiabetics. Interpretations and Conclusions: GSTM1 and GSTT1 deletions singly or together were associated with lower GST levels and higher oxidative stress in both diabetic and nondiabetic CKD. Interestingly, GSTT1 deletion appears to be associated with both diabetic and nondiabetic CKD irrespective of the GSTM1 status.

Paraoxonase-1 genetic polymorphisms and susceptibility to DNA damage in workers occupationally exposed to organophosphate pesticides

Human paraoxonase 1 (PON1) is a lipoprotein-associated enzyme involved in the detoxification of organophosphate pesticides (OPs) by hydrolyzing the bioactive oxons. Polymorphisms of the PON1 gene are responsible for variation in the expression and catalytic activity of PON1 enzyme. In the present study, we have determined (a) the prevalence of two common PON1 polymorphisms, (b) the activity of PON1 and acetylcholinesterase enzymes, and (c) the influence of PON1 genotypes and phenotypes variation on DNA damage in workers exposed to OPs. We examined 230 subjects including 115 workers exposed to OPs and an equal number of normal healthy controls. The results revealed that PON1 activity toward paraoxon (179.19±39.36 vs. 241.52±42.32nmol/min/ml in controls) and phenylacetate (112.74±17.37 vs. 134.28±25.49μmol/min/ml in controls) was significantly lower in workers than in control subjects (p<0.001). No significant difference was observed in the distribution of genotypes and allelic frequencies of PON1(192)QR (Gln/Arg) and PON1(55)LM (Leu/Met) in workers and control subjects (p>0.05). The PON1 activity toward paraoxonase was found to be significantly higher in the R/R (Arg/Arg) genotypes than Q/R (Gln/Arg) and lowest in Q/Q (Gln/Gln) genotypes in both workers and control subjects (p<0.001). For PON1(55)LM (Leu/Met), PON1 activity toward paraoxonase was observed to be higher in individuals with L/L (Leu/Leu) genotypes and lowest in individuals with M/M (Met/Met) genotypes in both groups (p<0.001). No influence of PON1 genotypes and phenotypes was seen on the activity of acetylcholinesterase and arylesterase. The DNA damage was observed to be significantly higher in workers than in control subjects (p<0.05). Further, the individuals who showed least paraoxonase activity i.e., those with (Q/Q [Gln/Gln] and M/M [Met/Met]) genotypes showed significantly higher DNA damage compared to other isoforms in workers exposed to OPs (p<0.05). The results indicate that the individuals with PON1 Q/Q and M/M genotypes are more susceptible toward genotoxicity. In conclusion, the study suggests wide variation in enzyme activities and DNA damage due to polymorphisms in PON1 gene, which might have an important role in the identification of individual risk factors in workers occupationally exposed to OPs.