Rahul Pathak

Organochlorine pesticide residue levels and oxidative stress in preterm delivery cases

A number of studies have focused attention on various biochemical abnormalities evoked due to exposure to organochlorine pesticides (OCPs). The aim of the present study was to analyze the OCP residues in maternal and cord blood of women and assess the levels of different non-enzymatic oxidative stress markers as well as to establish correlation with OCP levels, if any. Thirty women in each group of full-term delivery (FTD; ≥37 weeks of gestation) and preterm delivery (PTD; <37 weeks of gestation) were enrolled in this study. Levels of OCPs like Hexachlorocyclohexane (HCH), endosulfan, p,p′ Dichlorodiphenyldichloroethylene (DDE) and p,p’ Dichlorodiphenyltrichloroethane (DDT) were analyzed by gas chromatography. Non-enzymatic oxidative stress was measured by the quantification of malondialhyde (MDA), protein carbonyl, reduced glutathione (GSH) and ferric-reducing ability of plasma (FRAP). MDA and protein carbonyl levels were increased significantly, while the levels of GSH and FRAP were decreased in PTD in comparison to FTD cases. We have observed higher levels of β-HCH and α-endosulfan and increased oxidative stress in PTD than FTD cases. In PTD cases, a significant positive correlation was observed between maternal blood levels of β-HCH and MDA (r = .78), β-HCH and GSH (r = —.65), γ-HCH and MDA (r = .89), γ-HCH and GSH (r = —.74) and α-endosulfan and MDA (r = .54) in PTD cases. We also found significant correlations between cord blood levels of β-HCH and MDA (r = .59), β-HCH and GSH (r = —.69), γ-HCH and MDA (r = .62) and α-endosulfan and MDA (r = .54) in PTD cases. In conclusion, our results suggest that higher levels of some of the OCP residues may be associated with PTD and increased oxidative stress.

Endosulfan and Other Organochlorine Pesticide Residues in Maternal and Cord Blood in North Indian Population

Humans are exposed to various environmental chemicals such as organochlorine pesticide residues, heavy metals, polychlorinatedbiphenyls (PCBs) etc. There is paucity of data regarding the present blood levels of organochlorine residues in North Indian population with reference to reproductive health. The present study was designed to analyze the levels of organochlorine pesticide residues in maternal and cord blood samples of normal healthy women with full term pregnancy to gain insight into the current status of pesticide burden in newborns. Hexachlorocyclohexane (HCH) contributed maximum towards the total organochlorine residues present in maternal and cord blood followed by endosulfan, pp′ DDE and pp′ DDT being the least. This is also the first report indicating endosulfan levels in this population. Our data indicates a transfer rate of 60–70% of these pesticides from mothers to newborns and this high rate of transfer of pesticides is of great concern as it may adversely affect the growth and development of newborn.

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.

Endosulfan-induced apoptosis and glutathione depletion in human peripheral blood mononuclear cells: Attenuation by N-acetylcysteine.

Present study investigated whether endosulfan, an organochlorine pesticide is able to deplete glutathione (GSH) and induce apoptosis in human peripheral blood mononuclear cells (PBMC) in vitro. The role of oxidative stress in the induction of apoptosis was also evaluated by the measurement of the GSH level in cell lysate. The protective role of N‐acetylcysteine (NAC) on endosulfan‐induced apoptosis was also studied. Isolated human PBMC were exposed to increasing concentrations (0–100 µM) of endosulfan (α/β at 70:30 mixture) alone and in combination with NAC (20 µM) up to 24 h. Apoptotic cell death was determined by Annexin‐V Cy3.18 binding and DNA fragmentation assays. Cellular GSH level was measured using dithionitrobenzene. Endosulfan at low concentrations, i.e., 5 and 10 µM, did not cause significant death during 6 h/12 h incubation, whereas a concentration‐dependent cell death was observed at 24 h. DNA fragmentation analysis revealed no appreciable difference between control cells and 5 µM/10 µM endosulfan treated cells, where only high molecular weight DNA band was observed. Significant ladder formation was observed at higher concentration, which is indicative of apoptotic cell death. Intracellular GSH levels decreased significantly in endosulfan‐treated cells in a dose‐dependent manner, showing a close correlation between oxidative stress and degree of apoptosis of PBMC. Cotreatment with NAC attenuated GSH depletion as well as apoptosis. Our results provide experimental evidence of involvement of oxidative stress in endosulfan‐mediated apoptosis in human PBMC in vitro.

Association of glutathione S-transferase M1 and T1 gene polymorphisms and oxidative stress markers in preterm labor

OBJECTIVE Oxidative stress and related gene polymorphism may be associated with the etiology of preterm labor (PTL). The present study was designed to investigate association of GSTM1 and GSTT1 gene polymorphisms with PTL and their relationship with oxidative stress markers. DESIGN AND METHODS Sixty cases of PTL and sixty three subjects of full term labor (FTL) were included in the study. Multiplex PCR was performed for GSTM1 and GSTT1 genes polymorphism and oxidative stress markers were analyzed. RESULT MDA and 8-OHdG levels were increased, while GSH was decreased in PTL than FTL subjects. Frequency of GSTM1-/GSTT1-(null) was significantly higher in PTL in comparison to FTL (p=0.028, OR=3.4). Subjects with GSTM1-/GSTT1+, GSTM1+/GSTT1-, GSTM1-/GSTT1- have significant differences of oxidative stress markers as compared to GSTM1+/GSTT1+ genotype. CONCLUSION GSTM1-/GSTT1- (null) genotype may be one of the associated genetic factor for the increased risk of PTL.

Intra uterine growth retardation: Association with organochlorine pesticide residue levels and oxidative stress markers

Intra uterine growth retardation (IUGR) is a major complication of pregnancy, affecting ∼5% to 10% of newborns. Hexachlorocyclohexane (HCH) is an organochlorine pesticide that consists of eight stereoisomers and γ-isomer is the only isomer that possesses insecticidal activity. The aim of the present study was to analyze the OCP residues in maternal and cord blood of women and to assess the level of oxidative stress markers as well as to establish correlation with OCP levels. Fifty women delivering neonates with low birth weight (IUGR) and equal number of women delivering normal birth weight babies (control) were recruited. We have observed higher levels of γ-HCH and T-HCH and increased oxidative stress markers in IUGR subjects versus control subjects. Significant correlations were also found between HCH isomers and oxidative stress markers in IUGR subjects. In conclusion, our results suggest that higher levels of HCH isomers may be associated with IUGR and increased oxidative stress.

Association between recurrent miscarriages and organochlorine pesticide levels.

OBJECTIVES Recurrent miscarriage (RM) is a challenging medical problem because of its unknown pathogenesis and etiology in most of the cases. Recent studies suggest the role of persistent environmental pollutants such as organochlorine pesticides (OCPs) in the etiology of RM. The present study was conducted to investigate possible associations of OCPs in the pathogenesis of RM. DESIGN AND METHODS Blood OCP levels were analyzed in women with RM (cases) and women with normal full term delivery with live birth (controls) by using a gas chromatograph equipped with an electron capture detector. RESULTS A statistically significant association (p=0.01) was observed between blood gamma-HCH levels and women with recurrent miscarriages. CONCLUSIONS This study suggests that high blood levels of gamma-HCH may be associated with risk of RM.

Comparison of oxidative stress among migraineurs, tension-type headache subjects, and a control group

Background: A primary headache, particularly migraine, is associated with oxidative stress during the attack. However, data regarding the interictal state in migraineurs and in those with tension-type headache (TTH) is limited. Objectives: (1) To assess the oxidative stress in migraineurs and TTH subjects in between the episodes and (2) to see if there is a difference in the degree of oxidative stress in the different subtypes of migraine and TTH. Materials and Methods: Fifty migraineurs, 50 patients with TTH, and 50 control subjects were included in this study after screening for the exclusion criteria. Diagnosis of headache was made according to the International Classification of Headache Disorders (ICHD)-2 criteria. A venous blood sample was collected from the antecubital vein at least 3 days after the last attack of headache. The sample was centrifuged immediately and the plasma was stored at –70°C. The ferric reducing activity of plasma (FRAP) and the malondialdehyde (MDA) levels were assessed using colorimetric methods. Statistical analysis was done with the help of SPSS for Windows, v 11.0. One way ANOVA with post hoc Tukey test, independent sample t test, univariate regression, and multivariate regression analysis were done as indicated. Results: Migraineurs had higher values of MDA and FRAP than the subjects in the other two groups (P<0.001). No difference was observed between the TTH group and the control group. FRAP levels were significantly higher in subjects who had mixed migraine (migraine with aura and without aura) as compared to those with only migraine without aura (mean difference 196.1; 95% CI = 27.3 to 364.9; P = 0.01). Similarly, oxidative stress was significantly higher in patients with episodic TTH as compared to those with chronic TTH (FRAP t = 3.16; P = 0.003 and MDA t = 2.75; P = 0.008). Conclusions: This study suggests that oxidative stress continues even between headache episodes in migraineurs but not in those with TTH. This could probably be consequent to the different pathophysiological mechanisms of TTH and migraine.

Assessment of Redox Imbalance in Idiopathic Fetal Growth Restricted Pregnancies

Background: Fetal growth restriction (FGR) is one of the most significant causes of perinatal morbidity and mortality. The known causes are poor maternal nutrition, hypertensive disorders complicating pregnancy, maternal medical disorders (multiple pregnancy, congenital fetal malformations), and lifestyle influences. However, in vast majority of cases, the cause still remains unknown. Recent studies have suggested the role of oxidative stress in the pathophysiology of FGR. The aim of this study was to evaluate non-enzymatic oxidative stress biomarkers in maternal and cord blood of idiopathic FGR cases. Methods: A total of 100 women subjects aged 18 to 35 years, who fulfilled the recruitment criteria, were enrolled in the study after taking an informed written consent. Non-enzymatic oxidative stress was measured by the quantification of 8-hydroxy-2-deoxy-guanosine (8-OHdG), malondialdehyde (MDA), protein carbonyl, reduced glutathione (GSH) and ferric reducing ability of plasma (FRAP) in maternal and cord blood samples of FGR pregnancies of idiopathic origin and compared with those of normal healthy mother-infant pairs. Results: The levels of 8-OHdG, MDA and protein carbonyl were significantly higher in the ‘idiopathic’ FGR group as compared to the controls, where as the GSH and FRAP were significantly lower. Conclusion: Increased oxidative stress has been found significantly associated with the increased risk of developing idiopathic FGR.