Ultrastructural effects of DDT, DDD, and DDE on neural cells of the chicken embryo model

Safe long-term therapy of Cushing's syndrome over 37 years with mitotane

While suggested, surgery is not always possible as a first-line treatment of Cushing's Disease (CD). In such cases, patients require medical therapy in order to prevent complications resulting from hypercortisolism. Although there has been a wide expansion in pharmacological options in recent years, mitotane was the agent of choice for treating hypercortisolism decades ago. Due to the introduction of other therapies, long-term experience with mitotane remains limited. Here, we report the case of a woman with CD who was treated with mitotane for 37 years. During the treatment period, biochemical and clinical disease control was achieved and the patient had two uncomplicated pregnancies. Drug-related side effects remained moderate and could be controlled by several dose adjustments. Our case highlights the ability of mitotane to allow an effective control of hypercortisolism and to represent a safe treatment option in special situations where CD requires an alternative therapeutic approach. Furthermore, we provide a literature review of the long-term use of mitotane and reported cases of pregnancy in the context of mitotane therapy.

Autophagy-related neurotoxicity is mediated via AHR and CAR in mouse neurons exposed to DDE

DDE (dichlorodiphenyldichloroethylene) is an environmental metabolite of the pesticide DDT, which is still present in the environment, and its insecticidal properties are used to fight malaria and the Zika virus disease. We showed for the first time that the neurotoxic effects of DDE involve autophagy, as demonstrated by elevated levels of Becn1, Map1lc3a/MAP1LC3A, Map1lc3b, and Nup62/NUP62 and an increase in autophagosome formation. The suggestion that the aryl hydrocarbon receptor (AHR) and the constitutive androstane receptor (CAR) are involved in the neurotoxic effect of DDE was supported by increases in the mRNA and protein expression of these receptors, as detected by qPCR, ELISA, immunofluorescence labeling and confocal microscopy. Selective antagonists of the receptors, including alpha-naphthoflavone, CH223191, and CINPA 1, inhibited p,p'-DDE- and o,p'-DDE-induced LDH release and caspase-3 activity, while specific siRNAs (Ahr and Car siRNA) reduced the levels of p,p'-DDE- and o,p'-DDE-induced autophagosome formation. Although the neurotoxic effects of DDE were isomer independent, the mechanisms of p,p'- and o,p'-DDE were isomer specific. Therefore, we identified previously unknown mechanisms of the neurotoxic actions of DDE that, in addition to inducing apoptosis, stimulate autophagy in mouse neocortical cultures and induce AHR and CAR signaling.

Foetal exposure to mitotane/Op'DDD: Post-natal study of four children

OBJECTIVE

Mitotane/Op'DDD is used in the treatment of adrenocortical carcinoma and for other causes of hypercortisolism. Mitotane inhibits cortisol secretion and displays adrenolytic and antitumor actions. This compound is a metabolite of the pesticide and endocrine disruptor DDT (dichlorodiphenyltrichloroethane) and is classified among teratogenic compounds worldwide. However, little is known about its effects on human development.

DESIGN

The outcome of four children exposed to mitotane during their intrauterine life was examined.

PATIENTS

Patients having conceived while taking mitotane, or with detectable mitotane plasma levels, were retrospectively recruited via the French COMETE and FIRENDO networks.

MEASUREMENTS

Mitotane in maternal plasma, adrenocortical hormones in children.

RESULTS

Three women treated with mitotane gave birth to four children. During early pregnancy, all patients had detectable mitotane plasma levels (0.9, 2.4 and 6.7 mg/L, respectively). During pregnancy, no foetal malformations were detected. The four exposed newborns presented at birth with apparently normal adrenal function and genitalia. One twin female had a low birthweight. Evaluation at birth and after 3 months, 2 years and 7 years of follow-up showed no significant neurological abnormality. Evaluation of adrenocortical functions showed no cortisol deficiency.

CONCLUSIONS

Unexpectedly, exposure of these four children to mitotane during foetal life seemed to have no clear teratogenic effect. However, considering the sub-therapeutic mitotane concentrations used here, the small number of cases, and because long-term follow-up is unknown, we strongly advise not to take mitotane during pregnancy and still recommend avoiding pregnancy, at least as long as mitotane plasma levels remain detectable.

The Crucial Involvement of Retinoid X Receptors in DDE Neurotoxicity

Dichlorodiphenyldichloroethylene (DDE) is a primary environmental and metabolic degradation product of the pesticide dichlorodiphenyltrichloroethane (DDT). It is one of the most toxic compounds belonging to organochlorines. DDE has never been commercially produced; however, the parent pesticide DDT is still used in some developing countries for disease-vector control of malaria. DDT and DDE remain in the environment because these chemicals are resistant to degradation and bioaccumulate in the food chain. Little is known, however, about DDE toxicity during the early stages of neural development. The results of the present study demonstrate that DDE induced a caspase-3-dependent apoptosis and caused the global DNA hypomethylation in mouse embryonic neuronal cells. This study also provided evidence for DDE-isomer-non-specific alterations of retinoid X receptor α (RXRα)- and retinoid X receptor β (RXRβ)-mediated intracellular signaling, including changes in the levels of the receptor mRNAs and changes in the protein levels of the receptors. DDE-induced stimulation of RXRα and RXRβ was verified using selective antagonist and specific siRNAs. Co-localization of RXRα and RXRβ was demonstrated using confocal microscopy. The apoptotic action of DDE was supported at the cellular level through Hoechst 33342 and calcein AM staining experiments. In conclusion, the results of the present study demonstrated that the stimulation of RXRα- and RXRβ-mediated intracellular signaling plays an important role in the propagation of DDE-induced apoptosis during early stages of neural development.

Isomer-nonspecific action of dichlorodiphenyltrichloroethane on aryl hydrocarbon receptor and G-protein-coupled receptor 30 intracellular signaling in apoptotic neuronal cells

Extended residual persistence of the pesticide dichlorodiphenyltrichloroethane (DDT) raises concerns about its long-term neurotoxic effects. Little is known, however, about DDT toxicity during the early stages of neural development. This study demonstrated that DDT-induced apoptosis of mouse embryonic neuronal cells is a caspase-9-, caspase-3-, and GSK-3β-dependent process, which involves p,p'-DDT-specific impairment of classical ERs. It also provided evidence for DDT-isomer-nonspecific alterations of AhR- and GPR30-mediated intracellular signaling, including changes in the levels of the receptor and receptor-regulated mRNAs, and also changes in the protein levels of the receptors. DDT-induced stimulation of AhR-signaling and reduction of GPR30-signaling were verified using selective ligands and specific siRNAs. Co-localization of the receptors was demonstrated with confocal microscopy, and the presence of functional GPR30 was detected by electrophysiology. This study demonstrates that stimulation of AhR-signaling and impairment of GPR30-signaling play important roles in the propagation of DDT-induced apoptosis during the early stages of neural development.

Enantioselective induction of cytotoxicity by o,p'-DDD in PC12 cells: implications of chirality in risk assessment of POPs metabolites

The increased release of chiral persistent organic pollutants (POPs) into the environment has resulted in more attention to the role of enantioselectivity in the fate and ecotoxicological effects of these compounds. Although the enantioselectivity of chiral POPs has been considered in previous studies, little effort has been expended to discern the enantiospecific effects of chiral POPs metabolites, which may impede comprehensive risk assessments of these chemicals. In the present study, o,p'-DDD, the chiral metabolite of o,p'-DDT, was used as a model chiral metabolite. First, a preferential chiral separation at 100% ethanol was employed to obtain a pure enantiomer. The enantioselective cytotoxicity of o,p'-DDD in rat cells (PC12) was evaluated by detecting activation of the cellular apoptosis and oxidative stress systems and microarray analysis. We have documented for the first time that R-(+)-o,p'-DDD increases apoptosis by selectively disturbing the oxidative system (enzymes and molecules) and regulating the transcription of Aven, Bid, Cideb and Tp53. By comparing the data from the present study to data derived from the parent compound, we concluded that the R-enantiomer is the more detrimental stereostructure for both o,p'-DDT and o,p'-DDD. This observed stereostructural effect is in line with the structure-activity relationship formulated at other structural levels. Biological activities of the chiral metabolites are likely to occur in the same absolute configuration between chiral POPs and their metabolites provided that they have the similar stereostructures.

p,p'-DDE induces apoptosis and mRNA expression of apoptosis-associated genes in testes of pubertal rats

One,1-dichloro-2,2 bis(p-chlorophenyl) ethylene (p,p'-DDE), the major metabolite of 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), is a known persistent organic pollutant and male reproductive toxicant. It has antiandrogenic effect. However, the mechanism by which p,p'-DDE exposure causes male reproductive toxicity remains unknown. To elucidate the mechanism underpinning the testicular effects of p,p'-DDE, we sought to investigate apoptotic effects and mRNA expression of apoptosis-associated genes in the testis of pubertal rats, including Fas, FasL, calpain-1, cytochrome c, Bax, Bcl-w, Bak, and caspase-3, -8, -9, -12. Animals were administered with different doses of p,p'-DDE (0, 20, 60, 100 mg/kg body weight) every other day by intraperitoneal injection for 10 days. The results indicated that p,p'-DDE exposure at over 20 mg/kg body weight showed the induction of apoptotic cell death. p,p'-DDE could induce decrease in SOD and GSH-Px activity of serum in 60 mg/kg body weight group. Significant elevations in the mRNA levels of Fas, FasL, calpain-1, cytochrome c, Bax, Bak, and caspase-3, -8, -9, -12 were observed in testis of rat treated with p,p'-DDE. Taken together, these results lead us to speculate that in vivo exposure to p,p'-DDE might induce testicular apoptosis in pubertal rats through the involvement of Fas/FasL, mitochondria and endoplasmic reticulum-mediated pathways.

An insight into ultrastructural and morphological alterations of platelets in neurodegenerative diseases

Platelets are evinced as a systemic tool in a variety of disorders, including neurodegenerative diseases. Evidence suggests that variations in the ultrastructure and morphology of platelets and related organelles are involved in the pathophysiology of diabetes, cancer, HIV/AIDS, cardiovascular and neurological diseases. Due to structural alterations of platelets in many diseases, it is informative to discuss the ultrastructural and morphological discrepancies of platelets in contemporary medical research. The present review reveals the usefulness of ultrastructural study in better understanding of the disease patterns and may help to improve the treatment regimes.

Estrogens of multiple classes and their role in mental health disease mechanisms

Gender and sex hormones can influence a variety of mental health states, including mood, cognitive development and function, and vulnerability to neurodegenerative diseases and brain damage. Functions of neuronal cells may be altered by estrogens depending upon the availability of different physiological estrogenic ligands; these ligands and their effects vary with life stages, the genetic or postgenetic regulation of receptor levels in specific tissues, or the intercession of competing nonphysiological ligands (either intentional or unintentional, beneficial to health or not). Here we review evidence for how different estrogens (physiological and environmental/dietary), acting via different estrogen receptor subtypes residing in alternative subcellular locations, influence brain functions and behavior. We also discuss the families of receptors and transporters for monoamine neurotransmitters and how they may interact with the estrogenic signaling pathways.

Differential regulation of dopamine transporter function and location by low concentrations of environmental estrogens and 17beta-estradiol

BACKGROUND

The effects of 17beta-estradiol (E2) and xenoestrogens (XEs) on dopamine transport may have important implications for the increased incidence of neurologic disorders, especially in women during life stages characterized by frequent hormonal fluctuations.

OBJECTIVE

We examined low concentrations of XEs [dieldrin, endosulfan, o', p'-dichlorodiphenyl-ethylene (DDE), nonylphenol (NP), and bisphenol A (BPA)] for nongenomic actions via action of membrane estrogen receptors (ERs).

METHODS

We measured activity of the dopamine transporter (DAT) by the efflux of 3H-dopamine in nontransfected nerve growth factor-differentiated PC12 rat pheochromocytoma cells expressing membrane DAT, ER-alpha, ER-beta, and G-protein-coupled receptor 30. We used a plate immunoassay to monitor trafficking of these proteins.

RESULTS

All compounds at 1 nM either caused efflux or inhibited efflux, or both; each compound evoked a distinct oscillatory pattern. At optimal times for each effect, we examined different concentrations of XEs. All XEs were active at some concentration < 10 nM, and dose responses were all nonmonotonic. For example, 10(-14) to 10(-11) M DDE caused significant efflux inhibition, whereas NP and BPA enhanced or inhibited efflux at several concentrations. We also measured the effects of E2/XE combinations; DDE potentiated E(2)-mediated dopamine efflux, whereas BPA inhibited it. In E2-induced efflux, 15% more ER-alpha trafficked to the membrane, whereas ER-beta waned; during BPA-induced efflux, 20% more DAT was trafficked to the plasma membrane.

CONCLUSIONS

Low levels of environmental estrogen contaminants acting as endocrine disruptors via membrane ERs can alter dopamine efflux temporal patterning and the trafficking of DAT and membrane ERs, providing a cellular mechanism that could explain the disruption of physiologic neurotransmitter function.