Neuroprotective effects of estradiol in mesencephalic dopaminergic neurons

Sensorimotor dysfunction due to developmental manganese exposure is less severe in adult female than male rats and partially improved by acute methylphenidate treatment

Epidemiological studies have reported associations between elevated manganese (Mn) exposure and poorer psychomotor performance in children. Our studies in adult male rats have established that this relationship is causal and that prolonged methylphenidate (MPH) treatment is efficacious in treating this area of dysfunction. However, it is unclear if sensitivity to these Mn deficits differs between females and males, and whether existing pharmacological therapies are efficacious in improving sensorimotor dysfunction in females. To address these questions, we used our rat model of childhood environmental Mn exposure and the Montoya staircase test to determine whether 1) there are sex differences in the lasting sensorimotor dysfunction caused by developmental Mn exposure, and 2) MPH treatment is efficacious in ameliorating the sensorimotor deficits in females. Female and male neonates were treated orally with Mn (50 mg Mn/kg/d) from postnatal day 1 to 21 and evaluated for skilled forelimb sensorimotor performance as adults. Subsequently, the efficacy of acute oral MPH treatment (doses of 0, 0.5, and 3.0 mg MPH/kg/d) was assessed in females using a within-subject MPH treatment design. Developmental postnatal Mn exposure produced lasting sensorimotor reaching and grasping deficits that were milder in females than in males. Acute MPH treatment of Mn-exposed females with the 0.5 mg/kg/d dose attenuated the reaching dysfunction without alleviating grasping dysfunction. These findings show sex-based variations in sensitivity to the sensorimotor impairment caused by developmental Mn exposure, and they are consistent with prior studies showing less vulnerability of females to Mn-induced dysfunction in other functional domains, possibly due to the protective effects of estrogen. Given our previous work showing the efficacy of MPH treatment to alleviate Mn-induced inattention, impulsiveness, and sensorimotor dysfunctions in adult male rats, they also highlight the need for further research into sex-based differences in cognitive and behavioral areas of brain function, and the efficacy of therapeutics in treating behavioral dysfunction in females. Supported by NIEHS R01ES028369.

Estrogens and the regulation of glucose metabolism

The main estrogens: estradiol, estrone, and their acyl-esters have been studied essentially related to their classical estrogenic and pharmacologic functions. However, their main effect in the body is probably the sustained control of core energy metabolism. Estrogen nuclear and membrane receptors show an extraordinary flexibility in the modulation of metabolic responses, and largely explain gender and age differences in energy metabolism: part of these mechanisms is already sufficiently known to justify both. With regard to energy, the estrogen molecular species act essentially through four key functions: (1) Facilitation of insulin secretion and control of glucose availability; (2) Modulation of energy partition, favoring the use of lipid as the main energy substrate when more available than carbohydrates; (3) Functional protection through antioxidant mechanisms; and (4) Central effects (largely through neural modulation) on whole body energy management. Analyzing the different actions of estrone, estradiol and their acyl esters, a tentative classification based on structure/effects has been postulated. Either separately or as a group, estrogens provide a comprehensive explanation that not all their quite diverse actions are related solely to specific molecules. As a group, they constitute a powerful synergic action complex. In consequence, estrogens may be considered wardens of energy homeostasis.

Combined neurodevelopmental exposure to deltamethrin and corticosterone is associated with Nr3c1 hypermethylation in the midbrain of male mice

Attention-Deficit Hyperactivity Disorder (ADHD) is one of the most common neurodevelopmental disorders and manifests inattention, hyperactivity, and impulsivity symptoms in childhood that can last throughout life. Genetic and environmental studies implicate the dopamine system in ADHD pathogenesis. Work from our group and that of others indicates that deltamethrin insecticide and stress exposure during neurodevelopment leads to alterations in dopamine function, and we hypothesized that exposure to both of these factors together would lead to synergistic effects on DNA methylation of key genes within the midbrain, a highly dopaminergic region, that could contribute to these findings. Through targeted next-generation sequencing of a panel of cortisol and dopamine pathway genes, we observed hypermethylation of the glucocorticoid receptor gene, Nr3c1, in the midbrain of C57/BL6N males in response to dual deltamethrin and corticosterone exposures during development. This is the first description of DNA methylation studies of Nr3c1 and key dopaminergic genes within the midbrain in response to a pyrethroid insecticide, corticosterone, and these two exposures together. Our results provide possible connections between environmental exposures that impact the dopamine system and the hypothalamic-pituitary-adrenal axis via changes in DNA methylation and provides new information about the presence of epigenetic effects in adulthood after exposure during neurodevelopment.

Beneficial effect of estrogen on nigrostriatal dopaminergic neurons in drug-naïve postmenopausal Parkinson's disease

This study aimed to investigate the potential beneficial effects of estrogen on nigrostriatal dopaminergic neuron degeneration in postmenopausal drug-naïve Parkinson's disease (PD). Based on the ratio of lifetime estrogen exposure length to the total length of the estrogen exposure and deprivation period, postmenopausal women with drug-naïve PD were divided into low (n = 31) and high (n = 31) estrogen exposure ratio groups. We performed a comparative analysis of the striatal dopamine transporter (DAT) availability between the two groups. Additionally, we evaluated the longitudinal change in the levodopa equivalent dose per month using a linear mixed model. The motor symptoms were more severe in the low estrogen exposure ratio group than in the high estrogen exposure ratio group (P = 0.016). PD patients in the two groups had significantly lower DAT availability on all striatal sub-regions except for ventral striatum than did age- and sex-matched normal controls. When comparing the two groups, PD patients in the low estrogen exposure ratio group exhibited significantly lower DAT availability in the posterior putamen (P = 0.024) and in the ventral putamen (P = 0.036) than those in the high estrogen exposure ratio group. The estimated monthly levodopa equivalent dose changes were 10.9 in the low estrogen exposure ratio group and 7.1 in the high estrogen exposure ratio group with a significant interaction between the two groups (P = 0.001). These in vivo data provide indirect evidence showing that estrogen may elicit a beneficial effect on nigrostriatal dopamine neurons in PD.

Dynamic thiol/disulfide homeostasis in children with attention deficit hyperactivity disorder and its relation with disease subtypes

BACKGROUND

The aim of this study was to evaluate a novel oxidative stress marker (thiol/disulfide homeostasis) in attention deficit hyperactivity disorder (ADHD) children for the first time in literature.

METHODS

Ninety children with ADHD diagnosed according to DSM-V and as control group, 65 healthy children were included to the study. Native thiol, total thiol, disulfide, disulfide/native thiol, disulfide/total thiol were compared between the groups.

RESULTS

Total and native thiol levels were significantly higher whereas the disulfide/native thiol ratios were significantly lower in children with ADHD. ADHD combined type appeared to have higher disulfide, disulfide/native thiol and disulfide/total thiol ratios compared to other subtypes. Disulfide levels of the males with ADHD were significantly higher than those of the females with ADHD.

CONCLUSION

This study suggests that thiol/disulfide homeostasis is abnormal in children with ADHD. It may be used as a novel OS marker in ADHD children because it is easy, practical, fully automated and relatively inexpensive.

A compensatory role for declarative memory in neurodevelopmental disorders

Most research on neurodevelopmental disorders has focused on their abnormalities. However, what remains intact may also be important. Increasing evidence suggests that declarative memory, a critical learning and memory system in the brain, remains largely functional in a number of neurodevelopmental disorders. Because declarative memory remains functional in these disorders, and because it can learn and retain numerous types of information, functions, and tasks, this system should be able to play compensatory roles for multiple types of impairments across the disorders. Here, we examine this hypothesis for specific language impairment, dyslexia, autism spectrum disorder, Tourette syndrome, and obsessive-compulsive disorder. We lay out specific predictions for the hypothesis and review existing behavioral, electrophysiological, and neuroimaging evidence. Overall, the evidence suggests that declarative memory indeed plays compensatory roles for a range of impairments across all five disorders. Finally, we discuss diagnostic, therapeutic and other implications.

Identification of ANKK1 rs1800497 variant in schizophrenia: new data and meta-analysis

One functional polymorphism (rs1800497) within the ankyrin repeat and kinase domain containing-1 gene (ANKK1) was reported to be associated with schizophrenia, but results among different studies vary and conclusions remain controversial. The present study sought to clarify this potential association among a population of Han Chinese with early onset schizophrenia using a case-control (396 patients and 399 controls) and family based study (103 trios). We then performed a meta-analysis (comprising 11 case-control and 2 family-based studies) based on the present literature. Results of the association study revealed no significant difference in allele and genotype frequencies between the cases and controls, and no significant transmission distortion was detected. Kaplan-Meier survival analysis showed that age at onset in schizophrenia was significantly associated with the rs1800497 polymorphism in female patients, but not in males. Female T allele carriers had a lower age at onset than those without T allele (log rank statistic χ(2) = 5.16, P = 0.023; corrected P = 0.046). Meta-analysis results indicated that rs1800497 is not associated with schizophrenia in the overall population (P = 0.77 for the case-control studies; P = 0.06 for the family-based studies). Our results support the hypothesis that rs1800497 polymorphism is likely to have a modifying rather than causative effect on schizophrenia. These findings may represent a significant genetic clue for the etiology of schizophrenia in females, but further investigation is required to clarify the exact role of ANKK1 in the development of schizophrenia.

Puerarin protects dopaminergic neurons in Parkinson's disease models

It has been acknowledged that oxidative stress, resulting in the apoptosis of dopaminergic neurons, is a key mechanism in the pathogenesis of Parkinson's disease (PD). Puerarin, extracted from the root of pueraria lobata, has been clinically used for ischemic heart disease and cerebrovascular diseases as an oxygen free radical scavenger. In this study, we aimed to explore the effect of puerarin on dopaminergic cell degeneration in vitro and in vivo and its possible underlying mechanisms. In SH-SY5Y cells, the reduction of cell viability, apoptosis rate and average DCFH-DA fluorescence intensity of puerarin-treated (0, 10, 50, 100 and 150 μM) cells were significantly lower than control group. In rotenone-based rodent models, puerarin treatment for 7 days ameliorated apomorphine-induced rotations significantly in Pue-50 and Pue-100 group by 45.65% and 53.06% in the first week, by 44.60% and 48.45% in the second week. Moreover, compared to control group, puerarin increased tyrosine hydroxylase (TH) expression in the substantia nigra by 85.52% and 84.26% in Pue-50 group and Pue-100 group, and upregulated the vesicular monoamine transporter 2 (VMAT2) by 41.24% in Pue-50 group and 35.20% in Pue-100 group, and decreased ubiquitin expression by 47.55% in Pue-50 group and 69.15% in Pue-100 group. These data indicated that puerarin alleviated the oxidative stress and apoptosis in a PD cellular model, protected the dopaminergic neurons against rotenone toxicity and decreased the abnormal protein overexpressing in PD animal models. These findings suggest that puerarin may develop into a neuroprotective alternative for patients with PD.

Sex-specific influence of DRD2 on ADHD-type temperament in a large population-based birth cohort

Attention-deficit/hyperactivity disorder (ADHD) is a childhood-onset neurodevelopmental disorder with a significant public-health impact. Previously, we described a candidate gene study in a population-based birth cohort that demonstrated an association with ADHD-affected males and the dopamine receptor D2 (DRD2). The current study evaluates potential associations of dopamine receptor genes and Cloninger temperament traits within this same sample. Participants with stringent lifetime ADHD diagnoses were ascertained systematically from the genetically isolated Northern Finland 1986 Birth Cohort (n=9432), resulting in 178 cases and 157 controls. Markers in all known dopamine receptor genes were genotyped. We report an association of DRD2 with low Persistence in females (rs1079727 P=0.02, rs1124491 P=0.02, rs1800497 P=0.03). The associated DRD2 minor allelic haplotype (CAA, P=0.03) is the same haplotype we previously associated with ADHD in males in this birth cohort. The current study further supports previous results on the role of DRD2 in individuals with ADHD. Investigations suggest that DRD2 may have an impact on both males and females, but the particular outcome appears sex-specific, manifesting as ADHD in males and low Persistence in females. Furthermore, these findings suggest that the putative role of low Persistence as an endophenotype for ADHD deserves further investigation.

GDNF contributes to oestrogen-mediated protection of midbrain dopaminergic neurones

Parkinson's disease (PD) is characterised by the preferential loss of dopaminergic neurones from the substantia nigra (SN) that leads to the hallmark motor disturbances. Animal and human studies suggest a beneficial effect of oestrogen to the nigrostriatal system, and the regulation of neurotrophic factor expression by oestrogens has been suggested as a possible mechanism contributing to that neuroprotective effect. The present study was designed to investigate whether the neuroprotection exerted by 17β-oestradiol on nigrostriatal dopaminergic neurones is mediated through the regulation of glial cell line-derived neurotrophic factor (GDNF) expression. Using an in vivo rat model of PD, we were able to confirm the relevance of 17β-oestradiol in defending dopaminergic neurones against 6-hydroxydopamine (6-OHDA) toxicity. 17β-oestradiol, released by micro-osmotic pumps, implanted 10 days before intrastriatal 6-OHDA injection, prevented the loss of dopaminergic neurones induced by 6-OHDA. 17β-oestradiol treatment also promoted an increase in GDNF protein levels both in the SN and striatum. To explore the relevance of GDNF increases to 17β-oestradiol neuroprotection, we analysed, in SN neurone-glia cultures, the effect of GDNF antibody neutralisation and RNA interference-mediated GDNF knockdown. The results showed that both GDNF neutralisation and GDNF silencing abolished the dopaminergic protection provided by 17β-oestradiol against 6-OHDA toxicity. Taken together, these results strongly identify GDNF as an important player in 17β-oestradiol-mediated dopaminergic neuroprotection.

Gender differences in motor and non-motor symptoms among Sardinian patients with Parkinson's disease

BACKGROUND

Parkinson's disease (PD) occurs more frequently in men than in women and a higher risk for PD development in males compared with females has been hypothesized, suggesting gender may be a significant factor in the development and progression of parkinsonism. To date, gender differences in non-motor symptoms are under-reported.

OBJECTIVE

To assess gender differences in motor and non-motor symptoms among Sardinian PD patients.

METHODS

One hundred fifty-six (91 male and 65 female) consecutive Sardinian PD outpatients were included in this analysis. Modified Hoehn and Yahr scale and UPDRS were used to assess motor symptoms, while non-motor disturbances were evaluated with the non-motor symptoms scale (NMSS). Presence of depression, anxiety and other iatrogenic behavioral disorders was also investigated. In order to determine how gender differences could be specific to PD, 132 age-matched normal controls were assessed with the NMSS.

RESULTS

Women were more likely than men to present with tremor as initial symptom (p<.025) and worse UPDRS instability score (p<.02). NMSS score in females was significantly higher than that in males (p<.018). A significantly higher severity in cardiovascular (p<0.002), sleep/fatigue (p<.018) and mood/apathy (p<.001) domains was observed in female PD patients, while the sexual dysfunction domain was reported with a significantly higher score in male patients (p<.017). Fatigue (p<.03), lack of motivation (p<.015) and sadness (p<.009) were observed significantly more frequent in females, while altered interest in sex was noted as more common in males (p<.001). Frequency of depression (p<.011) and anxiety (p<.001) was significantly higher in females, while male patients had increased frequency of compulsive sexual behaviors (p<.05). There was a significantly higher frequency of non-motor symptoms in eight domains in both male and female PD patients compared with controls (p<.001, for all comparisons, with the exception of urinary disturbances in females: p<.004). Only sexual dysfunctions were not significantly higher in male and female PD patients compared with controls.

DISCUSSION

The present study highlights the role of gender differences associated with the occurrence of motor and non-motor disorders and our findings indicate that spectrum and severity of non-motor symptoms may present with different gender distribution in PD patients, suggesting a possible sex-related effect.

Neurobiological Underpinnings of the Estrogen - Mood Relationship

Women are at a higher risk than men to develop mood disorders and depression. The increased risk is associated with fluctuating estrogen levels that occur during reproductive cycle events, particularly during the menopausal transition, a time characterized by drastic fluctuations in estrogen levels and increases in new onset and recurrent depression. Conversely, recent data show that hormone therapy, particularly transdermal estradiol formulations, may prevent mood disorders or even serve as a treatment regimen for women with diagnosed mood disturbances via estrogen regulation. While the exact mechanism is unknown, there is compelling scientific evidence indicating the neuromodulatory and neuroprotective effects of estrogen, which are directly relevant to mood symptomotology. Specifically, affective regulation has been linked to neural structures rich in estrogen receptors and estrogenic regulation of neurotransmitters. While a wealth of basic science, observational and clinical research support this rationale, potential mediating variables, such as estrogen formulation, proximity of administration to menopause, and the addition of progestins should be considered. Furthermore, the nature of postmenopausal exogenous hormone formulations in relation to premenopausal endogenous levels, as well as the ratio of estrone to estradiol warrant consideration.

Hormone replacement therapy and risk for neurodegenerative diseases

Over the past two decades, there has been a significant amount of research investigating the risks and benefits of hormone replacement therapy (HRT) with regards to neurodegenerative disease. Here, we review basic science studies, randomized clinical trials, and epidemiological studies, and discuss the putative neuroprotective effects of HRT in the context of Alzheimer's disease, Parkinson's disease, frontotemporal dementia, and HIV-associated neurocognitive disorder. Findings to date suggest a reduced risk of Alzheimer's disease and improved cognitive functioning of postmenopausal women who use 17β-estradiol. With regards to Parkinson's disease, there is consistent evidence from basic science studies for a neuroprotective effect of 17β-estradiol; however, results of clinical and epidemiological studies are inconclusive at this time, and there is a paucity of research examining the association between HRT and Parkinson's-related neurocognitive impairment. Even less understood are the effects of HRT on risk for frontotemporal dementia and HIV-associated neurocognitive disorder. Limits to the existing research are discussed, along with proposed future directions for the investigation of HRT and neurodegenerative diseases.

17β-estradiol prevents reduction of retinal phosphorylated 14-3-3 zeta protein levels following a neurotoxic insult

Previous studies demonstrated the substantial protective role of 17β-estradiol (E2) in several types of neuron, although its mechanism of action remains to be elucidated. In this study, we found that the levels of 14-3-3 zeta mRNA and phosphorylated and total 14-3-3 zeta proteins were significantly decreased in the rat retina after intravitreal injection of N-methyl-d-aspartate (NMDA). 17β-E2 implantation significantly inhibited NMDA-induced decreases in phosphorylated but not in total 14-3-3 zeta protein levels in the retina. There was a decrease in both phosphorylated and total 14-3-3 protein levels in RGC-5 cells, a retinal ganglion cell line, after glutamate and buthionine sulfoximine (BSO) exposure, and 17β-E2 treatment significantly inhibited only the decrease in phosphorylated but not in total 14-3-3 zeta protein levels. The cell viability assay showed substantial cell death after glutamate and BSO exposure and that 17β-E2 treatment significantly protects against this cell death. 17β-E2 treatment also significantly increased the level of phosphorylated 14-3-3 protein in RGC-5 cells without other treatments. These results suggest that a decrease in 14-3-3 zeta expression may be associated with retinal neurotoxicity induced by NMDA or the combination of glutamate and BSO. The regulation of 14-3-3 zeta phosphorylation is one possible mechanism of the protective effect of 17β-E2 in the retina.

Perinatal intermittent hypoxia alters γ-aminobutyric acid: a receptor levels in rat cerebellum

Perinatal hypoxia commonly causes brain injury in infants, but the time course and mechanisms underlying the preferential male injury are unclear. Intermittent hypoxia disturbs cerebellar γ-aminobutyric (GABA)-A receptor profiles during the perinatal period, possibly responding to transient excitatory processes associated with GABA(A) receptors. We examined whether hypoxic insults were particularly damaging to the male rodent cerebellum during a specific developmental time window. We evaluated cerebellar injury and GABA(A) receptor profiles following 5-h intermittent hypoxia (IH: 20.8% and 10.3% ambient oxygen, switched every 240s) or room-air control in groups of male and female rat pups on postnatal d 1-2, wk 1, or wk 3. The cerebella were harvested and compared between groups. The mRNA levels of GABA(A) receptors α6, normalized to a house-keeping gene GAPDH, and assessed using real-time reverse-transcriptase PCR assays were up-regulated by IH at wk 1, more extensively in male rats, with sex influencing the regulatory time-course. In contrast, GABA(A) α6 receptor protein expression levels, assessed using Western blot assays, reached a nadir at wk 1 in both male and female rats, possibly indicating involvement of a post-transcriptional mechanism. The extent of cerebellar damage and level of apoptosis, assessed by DNA fragmentation, were greatest in the wk 3 IH-exposed group. The findings suggest partial protection for female rats against early hypoxic insult in the cerebellum, and that down-regulation of GABA(A) receptors, rather than direct neural injury assessed by DNA fragmentation may modify cerebellar function, with potential later motor and other deficits.

An early treatment with 17-β-estradiol is neuroprotective against the long-term effects of neonatal ionizing radiation exposure

Ionizing radiations can induce oxidative stress on target tissues, acting mainly through reactive oxygen species (ROS). The aim of this work was to investigate if 17-β-estradiol (βE) was able to prevent hippocampal-related behavioral and biochemical changes induced by neonatal ionizing radiation exposure and to elucidate a potential neuroprotective mechanism. Male Wistar rats were irradiated with 5 Gy of X-rays between 24 and 48 h after birth. A subset of rats was subcutaneously administered with successive injections of βE or 17-α-estradiol (αE), prior and after irradiation. Rats were subjected to different behavioral tasks to evaluate habituation and associative memory as well as anxiety levels. Hippocampal ROS levels and protein kinase C (PKC) activity were also assessed. Results show that although βE was unable to prevent radiation-induced hippocampal PKC activity changes, most behavioral abnormalities were reversed. Moreover, hippocampal ROS levels in βE-treated irradiated rats approached control values. In addition, αE administered to irradiated animals was effective in preventing radiation-induced alterations. In conclusion, βE was able to counteract behavioral and biochemical changes induced in irradiated animals, probably acting through an antioxidant mechanism.

The role of dopamine transporter (SLC6A3) and dopamine D2 receptor/ankyrin repeat and kinase domain containing 1 (DRD2/ANKK1) gene polymorphisms in personality traits

Variations in personality traits are caused by interactions between multiple genes of small effect and environmental factors. To date, gender- and ethnicity-specific variations in personality have been established. In the present study, we aimed to test: (1) the effects of four polymorphisms of dopamine system genes: ANKK1/DRD2 Taq1A, DRD2 rs6275, SLC6A3 40-bp VNTR and rs27072, on personality traits; (2) whether these effects differ between men and women and between Russians and Tatars. A sample of 652 healthy individuals (222 men and 430 women) of Caucasian origin (233 Russians and 419 Tatars) from Russia was subjected to personality traits assessment with Eysenck Personality Inventory (EPI) and Temperament and Character Inventory-125 (TCI-125). The associations between each personality trait and polymorphisms were assessed with regression models adjusted for gender and ethnicity. There were significant effects of ANKK1/DRD2 Taq1A on Neuroticism (p=0.016) and of SLC6A3 rs27072 on Persistence (p=0.021) in both genders. The association between ANKK1/DRD2 Taq1A A2/A2-genotype and higher Novelty Seeking and lower Reward Dependence was shown in men only (p for gender interaction=0.018). In women only, there was a significant association between SLC6A3 10R*G-haplotype and higher Persistence (p=0.002). Our findings provide evidence for a modifying effect of gender on the associations between dopamine system genes and approach-related traits (in men) and Persistence (in women).

Estrogen or estrogen receptor agonist inhibits lipopolysaccharide induced microglial activation and death

Inflammation is an important pathogenic mechanism in many neurodegenerative disorders. Activated microglia play a pivotal role in releasing pro-inflammatory factors including interleukin-1 (IL-1), tumor necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2) for inducing inflammation. While microglia mediated inflammation is essential in maintaining CNS homeostasis, chronic inflammation results in activation of proteases for cell death. Here, we examined the effect of PPT (estrogen receptor α agonist), DPN (estrogen receptor β agonist), and estrogen on rat primary microglia following exposure to lipopolysaccharide (LPS). Exposure of microglia to LPS (200 ng/ml) for 24 h induced cell death. After LPS toxicity for 15 min, microglia were treated with 25 nM PPT, 25 nM DPN, or 100 nM estrogen that prevented cell death by attenuating the release of IL-1α, IL-1β, TNF-α, and COX-2. Treatment of cells with 100 nM fulvestrant (estrogen receptor antagonist) prior to addition of PPT, DPN, or estrogen significantly decreased their ability to prevent cell death, indicating involvement of estrogen receptor (ER) in providing PPT, DPN, or estrogen mediated cytoprotection. Reverse transcriptase polymerase chain reaction (RT-PCR) analyses showed alterations in mRNA expression of Bax, Bcl-2, calpain, and calpastatin during apoptosis. We also examined mRNA expression of ERβ and ERα following exposure of microglia to LPS and subsequent treatment with PPT, DPN, or estrogen. We found that estrogen or estrogen receptor agonists upregulated expression of ERs. Overall, results indicate that estrogen receptor agonist or estrogen uses a receptor mediated pathway to protect microglia from LPS toxicity.

Gender-specific role of mitochondria in the vulnerability of 6-hydroxydopamine-treated mesencephalic neurons

Many neurodegenerative diseases, such as Morbus Parkinson, exhibit a gender-dependency showing a higher incidence in men than women. Most of the neurodegenerative disorders involve either causally or consequently a dysfunction of mitochondria. Therefore, neuronal mitochondria may demonstrate a gender-specificity with respect to structural and functional characteristics of these organelles during toxic and degenerative processes. The application of 6-OHDA (6-hydroxydopamine) in vitro and in vivo represents a well-accepted experimental model of Parkinson's disease causing Parkinsonian symptoms. Besides the known effects of 6-OHDA on mitochondria and neuronal survivability, we aimed to demonstrate that the mitochondrial neurotoxin affects the morphology and survival of primary dopaminergic and non-dopaminergic neurons in the mesencephalon in a gender-specific manner by influencing the transcription of mitochondrial genes, ATP and reactive oxygen species production. Our data suggest that cell death in response to 6-OHDA is primarily caused due to increased oxidative stress which is more pronounced in male than in female mesencephalic neurons.

Impact of the dopamine receptor gene family on temperament traits in a population-based birth cohort

Although the genetic determinants of personality have been intensively investigated especially since Cloninger proposed his psychobiological model of temperament and character, findings to date remain inconclusive and very few studies have addressed the topic in large population cohorts. In the current study we investigated one gene family in its entirety by addressing the role of all known dopamine receptor genes, DRD1-DRD5, on Cloninger's temperament traits in a Finnish population-based birth cohort. The study sample (n = 1,434) was ascertained from the Northern Finland Birth Cohort 1966 with over 5,000 study individuals tested at the age of 31 years. We utilized the genetic homogeneity and genealogical structure of this population to uncover putative effects of these genes on temperament traits at the population level. Our strategy utilizing a large birth cohort and its well established genealogical structure represents an optimal design for studying normally distributed traits. We also wished to provide a comprehensive view to one biologically relevant gene family instead of testing single candidate genes. We report evidence of association of several SNPs at the 5' end of dopamine receptor D2 (DRD2) with Novelty seeking (low) and Harm avoidance (high), and at the 3' end of DRD2 with Persistence. The strongest evidence of association emerged from females. Our study supports the involvement of the dopamine pathway in temperament traits, in particular underlining the role of DRD2 in Novelty seeking, Harm avoidance and Persistence.

Estrogen receptor (ER) beta modulates ERalpha responses to estrogens in the developing rat ventromedial nucleus of the hypothalamus

The mechanisms by which estradiol exerts specific actions on neural function are unclear. In brain the actions of estrogen receptor (ER) alpha are well documented, whereas the functions of ERbeta are not yet fully elucidated. Here, we report that ERbeta inhibits the activity of ERalpha in an anatomically specific manner within the neonatal (postnatal d 7) brain. Using selective agonists we demonstrate that the selective activation of ERalpha in the relative absence of ERbeta activation induces progesterone receptor expression to a greater extent than estradiol alone in the ventromedial nucleus, but not the medial preoptic nucleus, despite high ERalpha expression. Selective activation of ERbeta attenuates the ERalpha-mediated increase in progesterone receptor expression in the ventromedial nucleus but has no effect in medial preoptic nucleus. These results suggest that ERalpha/ERbeta interactions may regulate the effects of estrogens on neural development and reveal the neonatal brain as a unique model in which to study the specificity of steroid-induced gene expression.

Gender differences and estrogen effects in parkin null mice

Estrogens are considered neurotrophic for dopamine neurons. Parkinson's disease is more frequent in males than in females, and more prevalent in females with short reproductive life. Estrogens are neuroprotective against neurotoxic agents for dopamine neurons in vivo and in vitro. Here, we have investigated the role of estrogens in wild-type (WT) and parkin null mice (PK-/-). WT mice present sexual dimorphisms in neuroprotective mechanisms (Bcl-2/Bax, chaperones, and GSH), but some of these inter-sex differences disappear in PK-/-. Tyrosine hydroxylase (TH) protein and TH+ cells decreased earlier and more severely in female than in male PK-/- mice. Neuronal cultures from midbrain of WT and PK-/- mice were treated with estradiol from 10 min to 48 h. Short-term treatments activated the mitogen-activated protein kinase pathway of WT and PK-/- neurons and the phosphatidylinositol 3'-kinase/AKT/glycogen synthase kinase-3 pathway of WT but not of PK-/- cultures. Long-term treatments with estradiol increased the number of TH+ neurons, the TH expression, and the extension of neurites, and decreased the level of apoptosis, the expression of glial fibrillary acidic protein, and the number of microglial cells in WT but not in PK-/- cultures. The levels of estrogen receptor-alpha were elevated in midbrain cultures and in the striatum of adult PK-/- male mice, suggesting that suppression of parkin changes the estrogen receptor-alpha turnover. From our data, it appears that parkin participates in the cellular estrogen response which could be of interest in the management of parkin-related Parkinson's disease patients.

Functional alterations of the nigrostriatal dopamine system in estrogen receptor-alpha knockout (ERKO) mice

Estrogen represents an important factor for the development and function of the nigrostriatal dopamine system. Estrogen also controls sex-specific differentiation and activity of the nigrostriatal dopaminergic system. We used an estrogen receptor-alpha knockout (-/-) model (ERKO) to study the influence of this particular receptor subtype on the regulation of functional characteristics of the male and female nigrostriatal dopamine system. On the striatal level, we found a sex-specific regulation of dopamine D1 receptors (D1) and dopamine receptor-interacting protein 78 (Drip78). In female (-/-) mice D1 receptor expression levels were increased compared to wild type (wt) animals, whereas in male (-/-) mice Drip78 mRNA levels were decreased compared to wt. In the midbrain, expression of tyrosine hydroxylase (TH) and brain-derived neurotrophic factor (BDNF) was reduced in (-/-) mice of both sexes. Glial cell line-derived neurotrophic factor (GDNF) expression was not affected. These data demonstrate that the integrity of estrogen receptor-alpha (ERalpha) signalling is necessary for the regulation of gene expression of proteins known to be important for the function of the nigrostriatal system at the postsynaptic striatal and presynaptic midbrain level.

Dopaminergic dysfunction in attention deficit hyperactivity disorder (ADHD), differences between pharmacologically treated and never treated young adults: a 3,4-dihdroxy-6-[18F]fluorophenyl-l-alanine PET study

The dopaminergic system plays a key role in attention-deficit/hyperactivity disorder (ADHD). Methylphenidate (MP), a dopamine (DA) reuptake inhibitor, is a drug of first choice for treating ADHD. This cross-over study investigated alterations in DA metabolism in young males with ADHD who had never been pharmacologically treated and MP-treated patients in comparison to healthy subjects. Dynamic 3,4-dihdroxy-6-[18F]fluorophenyl-L-alanine (FDOPA) PET scans were carried out on 20 male patients with ADHD and 18 healthy men. Eight ADHD patients had never been treated with psychostimulants, the rest had received MP. Based on the tissue-slope-intercept plot parametric images of FDOPA influx rate constant (Ki) were generated for each subject from dynamic 3D FDOPA datasets and transformed into standard stereotactic space. First a volume of interest analysis was performed on each single subject. In a second step data were introduced to a SPM2 analysis to detect significant changes in mean voxel Ki values between the normal control group and each patient group. In comparison to controls, ADHD patients as a group (irrespective of treatment status) showed a lower Ki in bilateral putamen, amygdala and dorsal midbrain. There was a lower Ki in the left putamen, right amygdala and right dorsal midbrain in untreated patients compared to controls together with a relative higher influx in the left amygdala and right anterior cingulate cortex. In contrast, methylphenidate treatment was associated with a significantly lower Ki in the striatum and amygdala bilaterally, and in the right dorsal midbrain. Untreated young adult ADHD patients showed a dopamine dysfunction that might be partly due to compensatory mechanisms. MP seems to down-regulate dopamine turnover. This effect might be one component in the mechanism of action of this drug in ADHD treatment.

ADHD candidate gene study in a population-based birth cohort: association with DBH and DRD2

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) is a common childhood-onset disorder with a significant impact on public health. Although a genetic contribution to risk is evident, predisposing genetic determinants remain largely unknown despite extensive research. So far, the most promising candidate genes have been those involved in dopamine and serotonin pathways. This study tests a series of allelic variants within such candidate genes to determine their potential influence on ADHD susceptibility.

METHOD

We used a population sample ascertained from a birth cohort of a subpopulation of Finland, characterized by founder effect and isolation, thus minimizing genetic heterogeneity. The subjects were systematically ascertained using DSM-IV diagnostic criteria for ADHD from the Northern Finland Birth Cohort 1986 of more than 9,000 individuals, resulting in the study sample of 188 ADHD cases and 166 controls. We genotyped markers in 13 candidate genes, including critical components of dopamine and serotonin pathways.

RESULTS

We report evidence for association of ADHD with allelic variants of the dopamine beta-hydroxylase (DBH) and dopamine receptor D2 (DRD2) genes.

CONCLUSIONS

Our study supports the involvement of the dopamine pathway in the etiology of ADHD; specifically the genes DBH and DRD2 deserve more attention in further studies.

Loss of aromatase cytochrome P450 function as a risk factor for Parkinson's disease?

The final step in the physiological synthesis of 17beta estradiol (E(2)) is aromatization of precursor testosterone by a CYP19 gene product, cytochrome P450 estrogen aromatase in the C19 steroid metabolic pathway. Within the central nervous system (CNS) the presence, distribution, and activity of aromatase have been well characterized. Developmental stage and injury are known modulators of brain enzyme activity, where both neurons and glial cells reportedly have the capability to synthesize this key estrogenic enzyme. The gonadal steroid E(2) is a critical survival, neurotrophic and neuroprotective factor for dopaminergic neurons of the substantia nigra pars compacta (SNpc), the cells that degenerate in Parkinson's disease (PD). In previous studies we underlined a crucial role for the estrogenic status at the time of injury in dictating vulnerability to the parkinsonian neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Our ongoing studies address the contribution of brain aromatase and extragonadal E(2) as vulnerability factors for PD pathology in female brain, by exposing aromatase knockout (ArKO, -/-) female mice which are unable to synthesize estrogens to MPTP. Our initial results indicate that aromatase deficiency from early embryonic life significantly impairs the functional integrity of SNpc tyrosine hydroxylase-positive neurons and dopamine transporter innervation of the caudate-putamen in adulthood. In addition, ArKO females exhibited a far greater vulnerability to MPTP-induced nigrostriatal damage as compared to their Wt type gonadally intact and gonadectomized counterparts. Characterization of this novel implication of P450 aromatase as determining factor for PD vulnerability may unravel new avenues for the understanding and development of novel therapeutic approaches for Parkinson's disease.

Estrogen and the development and protection of nigrostriatal dopaminergic neurons: concerted action of a multitude of signals, protective molecules, and growth factors

The nigrostriatal dopamine system comprises the dopaminergic neurons located in the ventral midbrain, their axonal connections to the forebrain, and their direct cellular target cells in the striatal complex, i.e. GABAergic neurons. The major function of the nigrostriatal dopaminergic unit is the coordination and fine tuning of motor functions at the extrapyramidal level. Numerous biologically active factors including different types of growth factors (neurotrophins, members of the TGFbeta family, IGFs) and peptide/steroid hormones have been identified in the past to be implicated in the regulation of developmental aspects of this neural system. Some of these developmentally active determinants have in addition been found to play a crucial role in the mediation of neuroprotection concerning dopaminergic neurons. Estrogen was identified as such a compound interfering with embryonic neuronal differentiation and cell survival. The physiological mechanisms underlying these effects are very complex and include interactions with other developmental signals (growth factors), inflammatory processes as well as apoptotic events, but also require the activation of nonneuronal cells such as astrocytes. It appears that estrogen is assuming control over or at least influences a multitude of developmental and protective cellular mechanisms rather than taking over the part of a singular protagonist.

Estrogen counteracts ozone-induced oxidative stress and nigral neuronal death

Oxidative stress is implicated in the premature death of dopamine neurons in substantia nigra in Parkinson's disease. The incidence of Parkinson's disease is higher in men than in women, and estrogen may provide neuroprotection against oxidative damage. We examined the protective effects of estrogen on rat nigral death after chronic ozone inhalation. Ozone inhalation produced impaired nigral cell morphology and loss of dopamine neurons in ovariectomized rats. This was counteracted after 60 days of 17beta-estradiol treatment, when blood levels were highest. These results indicate that ozone exposure may be a useful Parkinson's disease model and neuroprotection afforded by 17beta-estradiol is dependent on the high levels achieved after its prolonged administration.

Select estrogens within the complex formulation of conjugated equine estrogens (Premarin) are protective against neurodegenerative insults: implications for a composition of estrogen therapy to promote neuronal function and prevent Alzheimer's disease

BACKGROUND

Results of the Women's Health Initiative Memory Study (WHIMS) raised concerns regarding the timing and formulation of hormone interventions. Conjugated equine estrogens (CEE), used as the estrogen therapy in the WHIMS trial, is a complex formulation containing multiple estrogens, including several not secreted by human ovaries, as well as other biologically active steroids. Although the full spectrum of estrogenic components present in CEE has not yet been resolved, 10 estrogens have been identified. In the present study, we sought to determine which estrogenic components, at concentrations commensurate with their plasma levels achieved following a single oral dose of 0.625 mg CEE (the dose used in the WHIMS trial) in women, are neuroprotective and whether combinations of those neuroprotective estrogens provide added benefit. Further, we sought, through computer-aided modeling analyses, to investigate the potential correlation of the molecular mechanisms that conferred estrogen neuroprotection with estrogen interactions with the estrogen receptor (ER).

RESULTS

Cultured basal forebrain neurons were exposed to either beta-amyloid(25-35) or excitotoxic glutamate with or without pretreatment with estrogens followed by neuroprotection analyses. Three indicators of neuroprotection that rely on different aspects of neuronal damage and viability, LDH release, intracellular ATP level and MTT formazan formation, were used to assess neuroprotective efficacy. Results of these analyses indicate that the estrogens, 17alpha-estradiol, 17beta-estradiol, equilin, 17alpha-dihydroequilin, equilinen, 17alpha-dihydroequilenin, 17beta-dihydroequilenin, and Delta8,9-dehydroestrone were each significantly neuroprotective in reducing neuronal plasma membrane damage induced by glutamate excitotoxicity. Of these estrogens, 17beta-estradiol and Delta8,9-dehydroestrone were effective in protecting neurons against beta-amyloid25-35-induced intracellular ATP decline. Coadministration of two out of three neuroprotective estrogens, 17beta-estradiol, equilin and Delta8,9-dehydroestrone, exerted greater neuroprotective efficacy than individual estrogens. Computer-aided analyses to determine structure/function relationships between the estrogenic structures and their neuroprotective activity revealed that the predicted intermolecular interactions of estrogen analogues with ER correlate to their overall neuroprotective efficacy.

CONCLUSION

The present study provides the first documentation of the neuroprotective profile of individual estrogens contained within the complex formulation of CEE at concentrations commensurate with their plasma levels achieved after an oral administration of 0.625 mg CEE in women. Our analyses demonstrate that select estrogens within the complex formulation of CEE contribute to its neuroprotective efficacy. Moreover, our data predict that the magnitude of neuroprotection induced by individual estrogens at relatively low concentrations may be clinically undetectable and ineffective, whereas, a combination of select neuroprotective estrogens could provide an increased and clinically meaningful efficacy. More importantly, these data suggest a strategy for determining neurological efficacy and rational design and development of a composition of estrogen therapy to alleviate climacteric symptoms, promote neurological health, and prevent age-related neurodegeneration, such as AD, in postmenopausal women.

Gender and the Parkinson's disease phenotype

OBJECTIVES

To determine whether there are gender differences in the Parkinson's disease (PD) phenotype using a large clinic-based cohort.

METHODS

We examined gender differences in demographic, historical and clinical characteristics in a consecutive clinical series of 1,264 individuals diagnosed with PD.

RESULTS

The majority of individuals in the sample were male (67 %). Comparative analyses showed males and females were not significantly different on most demographic and historical characteristics. For both genders, the mean age and the mean age at symptomatic onset were about 70 and 63 years, respectively and, thus, disease duration was not significantly different between genders. The proportion of individuals with a positive family history of PD (15 %) was similar for both genders. A positive history of depression was significantly higher in females (35 % vs. 24 %). The UPDRS instability score was significantly worse among females, whereas the rigidity score was significantly worse for males. Females showed significantly worse ADL capacity and a more advanced H&Y stage. The proportion of individuals receiving antiparkinsonian medication (about 66 %) and time between the last dose and the clinical evaluation (about 4 hours) was similar for both genders. There was a trend for lower daily levodopa equivalence dosage and more severe dyskinesia score among females but these differences did not reach statistical significance after Bonferroni correction.

CONCLUSIONS

The majority of comparisons tended to highlight the commonalities in the PD phenotype between genders, particularly in reference to historical and early disease stage characteristics. However, gender may be an important factor related to the expression of PD features during the symptomatic disease course.

Oestrogens prevent loss of dopamine transporter (DAT) and vesicular monoamine transporter (VMAT2) in substantia nigra of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mice

Previous results from our laboratory have shown that 17beta-oestradiol prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) striatal dopamine depletion. 17beta-oestradiol, oestriol and oestrone are the naturally occurring oestogens in humans. Using various dopamine markers, the present study investigated whether oestrone and oestriol such as 17beta-oestradiol have neuroprotective activity in MPTP-treated mice. Male mice were treated with 17beta-oestradiol, oestriol or oestrone for 5 days before and after MPTP administration, and were compared with nonlesioned mice receiving the same treatment. Striatal concentrations of dopamine and its metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), were assayed by high-performance liquid chromatography. Dopamine transporter (DAT) and vesicular monoamine transporter (VMAT2) specific binding were measured by autoradiography. DAT, VMAT2 and tyrosine hydroxylase mRNA levels were measured by in situ hybridisation. MPTP induced a loss of DAT and VMAT2 specific binding in the striatum and substantia nigra, as well as a decrease of VMAT2 mRNA in the substantia nigra. 17beta-oestradiol treatment prevented the loss of these dopaminergic markers, as well as striatal concentrations of dopamine, DOPAC and HVA. Mice receiving oestriol and oestrone showed catecholamine concentrations comparable to MPTP mice. Oestriol treatment had no effect on dopaminergic markers in MPTP mice whereas oestrone prevented striatal DAT loss and the decrease of VMAT2 mRNA in the substantia nigra. In nonlesioned mice, 17beta-oestradiol, oestriol or oestrone had no effect on all the dopaminergic markers investigated. In conclusion, a weak or a lack of effect of oestriol and oestrone was observed compared to 17beta-oestradiol in MPTP mice and none of these steroids had an effect in nonlesioned mice. A DAT and VMAT2 specific binding decrease after MPTP in the striatum and substantia nigra, as well as a decrease of substantia nigra VMAT2 mRNA, was observed and could be prevented by oestradiol.

Effects of 17β-estradiol on the spontaneous activity of substantia nigra neurons: Evidence for a non-genomic mechanism

Clinical and experimental evidence suggests that female sex hormones (estradiol and progesterone) affect structures in the central nervous system that are involved in the control of movement. Using conventional electrophysiological techniques to record extracellular action potentials in the substantia nigra of urethane-anesthetized rats, it was found that microiontophoretic applications of 17beta-estradiol were able to modify the spontaneous activity of nigral neurons. 17beta-estradiol produced significant changes in the firing frequency (excitation and inhibition) and increased the rhythmicity of the majority of cells studied. These changes appear to be influenced by the sex and the hormonal status of the animal. Effects are of short latency and are not blocked by the administration of tamoxifen. We conclude that estradiol produces changes in the firing rate and discharge pattern of nigral cells in the urethane-anesthetized rat via a non-genomic mechanism.

Study of familial Parkinson's disease in Russia, Uzbekistan, and Zambia

OBJECTIVE

The aims of this study were (A) to determine inheritance patterns of familial Parkinson's disease in three different geographical areas (Russia, Uzbekistan, and Zambia); (B) compare clinical characteristics of familial with sporadic Parkinson's disease; and (C) assess whether there were ethnic differences in clinical manifestations of the disease.

METHODS

Fifty two index cases of familial Parkinson's disease in Moscow, 55 in Tashkent, and 27 in Lusaka were selected on the basis of the typical clinical features of Parkinson's disease with a familial history. The sex ratio, transmission patterns, and segregation ratio were determined by pedigree analysis.

RESULTS

Familial Parkinson's disease was found in all three countries (30 families in Russia, 12 in Uzbekistan, and seven in Zambia), and appeared more common in Russia. Both autosomal dominant and autosomal recessive patterns of inheritance were seen, but autosomal dominance was more common in all countries.

CONCLUSIONS

In all three countries men have a higher risk of developing Parkinson's disease than women and there are ethnic differences in clinical manifestations of the disease. The onset of both familial and sporadic Parkinson's disease in Zambian patients occurs at a younger age and is associated with slow progression and a benign course, and generally responds well to levodopa treatment.

Molecular endocrinology and physiology of the aging central nervous system

Aging is associated with a progressive decline in physical and cognitive functions. The impact of age-dependent endocrine changes regulated by the central nervous system on the dynamics of neuronal behavior, neurodegeneration, cognition, biological rhythms, sexual behavior, and metabolism are reviewed. We also briefly review how functional deficits associated with increases in glucocorticoids and cytokines and declining production of sex steroids, GH, and IGF are likely exacerbated by age-dependent molecular misreading and alterations in components of signal transduction pathways and transcription factors.

Selective estrogen receptor modulators (SERMs) for the brain: current status and remaining challenges for developing NeuroSERMs

Multiple issues regarding the efficacy of estrogen action in the brain remain unresolved. These include the timing, formulation and duration of the therapy intervention. Moreover, issues of thrombotic and neoplastic risks must be factored into the design of estrogen alternatives developed to prevent age-associated neurodegenerative disorders, as well as other climacteric symptoms such as hot flush and sleep dysfunction. One strategy to address these issues is to develop molecules that selectively target and activate estrogen mechanisms of action in the brain while avoiding activation of estrogen receptors peripheral to the brain, particularly in reproductive organs. An overview of recent advances in our understanding of the molecular mechanisms of estrogen action is discussed in the context of designing an efficacious NeuroSERM that will activate cellular, biochemical and genomic events required for the promotion of memory function and neuronal survival. Pharmacological analyses of estrogen receptor subtypes and the case for a membrane-associated estrogen receptor splice variant in mediating these mechanisms are provided along with a summary of the activation profiles of existing clinically relevant estrogen alternatives or SERMs in neurons. Results of these endeavors have yielded insights into strategies for developing novel molecules with NeuroSERM potential in order to prevent brain related climacteric symptoms and neurodegenerative diseases.

Gender differences in antioxidant capacity of rat tissues determined by 2,2'-azinobis (3-ethylbenzothiazoline 6-sulfonate; ABTS) and ferric reducing antioxidant power (FRAP) assays

Differences in susceptibility to oxidative stress between males and females have been postulated. Several methods have been developed to assess the total antioxidant capacity of human serum or plasma, but just recently some of them were employed for measurement of antioxidant capacity of tissues. In this study, we measured and compared antioxidant capacity of heart, kidney, liver and brain tissues of male and female rats. Antioxidant capacity was determined using 2,2'-azinobis (3-ethylbenzothiazoline 6-sulfonate; ABTS) and ferric reducing antioxidant power (FRAP) assays. In the same samples, lipid peroxidation products of these tissues were analysed using thiobarbituric acid reactive substances (TBARS) assays. Antioxidant capacity of heart, kidney and liver tissues was higher in female than male rats for both FRAP and ABTS assays. We found positive correlation between FRAP and ABTS values for all tested tissues. FRAP and ABTS proved to be comparable, simple and quick methods for antioxidant capacity scanning in tissues. TBARS levels differed only for brain tissue, being higher in males. These results indicate stronger defense against oxidative damage in females for all observed tissues. These finding may account for the longer lifespan of females.

Cryopreservation of pig granulosa cells: effect of FSH addition to freezing medium

We cryopreserved swine granulosa cells by a slow cooling rate system; FSH was added to the freezing medium to test its effectiveness in protecting the cells. After thawing, proliferative activity, viability, steroidogenesis and apoptosis were tested; moreover, we determined heat shock protein (HSP70) production, to investigate the recovery from stress and superoxide dismutase (SOD) and catalase activity to evaluate a possible impairment of the antioxidant pathway. E2 production was enhanced by cryopreservation in particular with FSH; on the contrary, P4 production was inhibited by the freezing process in particular without FSH. Only the higher FSH concentration (10 ng/ml) stimulated steroid secretion in freshly collected cells; P4 production by cells cryopreserved in the presence and in absence of FSH was increased by both 5 and 10 ng/ml while the lowest concentration was effective in stimulating E2 production only when FSH was added to freezing medium. Freezing did not modify proliferative activity, while apoptosis was higher in frozen than in fresh cells. HSP70 production was lower in cells cryopreserved in presence of FSH, whose antioxidant metabolism was also conserved: SOD and catalase activities were similar to control. In conclusion, cryopreservation does not seem to markedly affect granulosa cells, in particular if they are frozen in presence of FSH; the gonadotrophin somehow improves their performances after thawing, probably stimulating E2 production and the antioxidant metabolism.

Effects of gender on neurologic and functional recovery after spinal cord injury

OBJECTIVE

To assess gender differences in neurologic and functional outcome measures in persons with spinal cord injury (SCI).

DESIGN

Case series.

SETTINGS

Model Spinal Cord Injury Systems (MSCIS) throughout the United States.

PARTICIPANTS

People (N=14,433) admitted to an MSCIS within 30 days of injury.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Improvement in American Spinal Injury Association (ASIA) motor index score, ASIA Impairment Scale, level of injury, and FIM instrument scores after SCI.

RESULTS

When examining subjects grouped by severity of injury, changes in ASIA motor index total scores, from system admission to 1-year anniversary, were significantly greater for women than men with either complete ( P =.035) or incomplete ( P =.031) injuries. Functional comparison of men and women, using the FIM motor subscale, revealed that men had higher FIM motor scores at rehabilitation discharge among those with motor-complete injuries, except for those with C1-4 and C6 neurologic levels. Women with motor-incomplete high tetraplegia (C1-4 levels) had higher discharge FIM motor scores than did similarly afflicted men. There were no significant differences in FIM motor scores among men and women with other levels of motor incomplete SCI.

CONCLUSIONS

Gender differences in SCI were seen in several areas. Women may have more natural neurologic recovery than men; however, for a given level and degree of neurologic injury, men tend to do better functionally than women at time of discharge from rehabilitation. Future prospective study of the effects of estrogen on neurologic recovery and the effects of gender on functional potential are recommended.

A novel exon 5 mutation (N139H) in the SOD1 gene in a Spanish family associated with incomplete penetrance

BACKGROUND

Allelic heterogeneity and phenotype variability-especially in age at onset, penetrance and progression-are reported in ALS1 families. For this reason, SOD1 gene mutation data in ALS1 patients are currently being gathered to better understand the genotype-phenotype relationship in this disorder. Here, we report the clinical and molecular characteristics of a Spanish ALS1 family with incomplete penetrance.

PATIENTS AND METHODS

Clinical data including age at onset, initial topography, progression and survival were available in three affected members. Erythrocyte SOD1 activity was measured in four individuals. Analysis of the SOD1 gene was performed by PCR and direct sequencing.

RESULTS

A novel missense mutation in the exon 5 of the SOD1 gene, an A-to-C transversion at nucleotide position 1485 leading to N139H residue change, was identified in three family members. The phenotype was similar in all cases, with initial symptoms in the distal limb muscles and a mean survival time of around 4 years. Incomplete penetrance was observed in our family, as two obligate carriers did not develop any symptoms of amyotrophic lateral sclerosis (ALS).

CONCLUSIONS

N139H is the fifth SOD1 gene mutation reported in Spain, and the first one presenting with incomplete penetrance. Genetic counseling for at-risk relatives in these low-penetrance families could be difficult as some individuals harbouring the mutation remain asymptomatic throughout their lives. Further genetic characterisation of ALS1 families should provide information regarding the distribution of SOD1 mutants in different ethnic groups.

Aromatase expression by reactive astroglia is neuroprotective

The enzyme aromatase catalyzes the conversion of testosterone and other C19 steroids to estradiol. Under normal circumstances, the expression of aromatase in the central nervous system of mammals is restricted to neurons. However, the expression of the enzyme is induced in astrocytes in vitro by stressful stimuli. Furthermore, different types of brain injury induce in vivo the expression of aromatase in reactive astrocytes. The expression of aromatase by reactive astrocytes is neuroprotective, because the pharmacological inhibition of the enzyme in the brain exacerbates neuronal death after different forms of mild neurodegenerative stimuli that do not significantly affect neuronal survival under control conditions. These findings indicate that the induction of aromatase in reactive astrocytes, and the consecutive increase in the local production of estradiol in the brain at injured sites, may be an endogenous neural response to reduce the extent of neurodegenerative damage.

Estradiol attenuates programmed cell death after stroke-like injury

Estradiol is a known neurotrophic and neuroprotective factor. Our previous work demonstrated that replacement with physiological concentrations of estradiol protects the cortex against middle cerebral artery occlusion (MCAO)-induced cell death. The cerebral cortex exhibits caspase-dependent programmed cell death (PCD) in many models of focal cerebral ischemia. We hypothesized that estradiol attenuates PCD during stroke injury. The current study explored the temporospatial pattern of markers of PCD, their relationship to the evolution of injury, and their modulation by estradiol. Rats were ovariectomized and treated with either estradiol or vehicle. One week later, rats underwent MCAO, and brains were collected at 1, 4, 8, 16, and 24 hr. We assessed the temporospatial evolution of infarction volume, DNA fragmentation, and levels of spectrin cleavage products in ischemic cortex. Estradiol led to a delay and attenuation of injury-mediated DNA fragmentation as early as 8 hr after MCAO. Estradiol also dramatically reduced the level of the 120 kDa caspase-mediated spectrin breakdown product (SBDP120) at 4 hr but not at 8 or 16 hr. The SBDP150, produced by caspase and calpain, showed peak levels at 16 hr but was not altered by estradiol. These results strongly suggest that estradiol protects the ischemic cortex by attenuating PCD, thereby reducing caspase activity, DNA fragmentation, and subsequently, overall cell death. These studies deepen our understanding of the mechanisms underlying estrogen-mediated neuroprotection.

Lycopene II--effect on osteoblasts: the carotenoid lycopene stimulates cell proliferation and alkaline phosphatase activity of SaOS-2 cells

We explored the possibility that lycopene, a carotenoid that is abundant in tomatoes, has effects on proliferation and differentiation of osteoblasts, the cells responsible for bone formation. Human osteoblast-like osteosarcoma SaOS-2 cells were cultured for 24 hours, after which varying doses of a water-dispersible microemulsion preparation of lycopene or vehicle of the same dilution were added. The cells were further cultured for 24 to 144 hours, and then the cell numbers were counted. Lycopene at 10(-6) and 10(-5) M had significant stimulatory effects on cell numbers, compared with the corresponding vehicle treatment, at all time points from 24 to 144 hours. The effects of lycopene on activity of the differentiation marker alkaline phosphatase activity in the absence or presence of dexamethasone were shown to be dependent on the stage of cell differentiation. This is the first report on the effects of lycopene on osteoblasts of human origin; the results may have important applications in the prevention of osteoporosis.

An animal model with relevance to schizophrenia: sex-dependent cognitive deficits in osteogenic disorder-Shionogi rats induced by glutathione synthesis and dopamine uptake inhibition during development

Low glutathione levels have been observed in the prefrontal cortex and the cerebrospinal fluid of schizophrenic patients, possibly enhancing the cerebral susceptibility to oxidative stress. We used osteogenic disorder Shionogi mutant rats, which constitute an adequate model of the human redox regulation because both are unable to synthesize ascorbic acid. To study the long-term consequences of a glutathione deficit, we treated developing rats with L-buthionine-(S,R)-sulfoximine (BSO), an inhibitor of glutathione synthesis, and later investigated their behavior until adulthood. Moreover, some rats were treated with the dopamine uptake inhibitor GBR 12909 in order to elevate dopamine extracellular levels, thereby mimicking the dopamine hyperactivity proposed to be involved in schizophrenia. BSO and GBR 12909 alone or in combination minimally affected the development of spontaneous alternation or basic sensory and motor skills. A major effect of BSO alone or in combination with GBR 12909 was the induction of cataracts in both sexes, whereas GBR 12909 induced an elevation of body weight in females only. Sex and age-dependent effects of the treatments were observed in a test of object recognition. At postnatal day 65, whereas male rats treated with both BSO and GBR 12909 failed to discriminate between familiar and novel objects, females were not affected. At postnatal day 94, male object recognition capacity was diminished by BSO and GBR 12909 alone or in combination, whereas females were only affected by the combination of both drugs. Inhibition of brain glutathione synthesis and dopamine uptake in developing rats induce long-term cognitive deficits occurring in adulthood. Males are affected earlier and more intensively than females, at least concerning object recognition. The present study suggests that the low glutathione levels observed in schizophrenic patients may participate in the development of some of their cognitive deficits.

Estradiol differentially regulates c-Fos after focal cerebral ischemia

Estrogen replacement therapy enhances mood, delays cognitive decline, and reduces the risk of neurodegeneration. Our laboratory has shown previously that pretreatment with low physiological levels of estradiol protects against middle cerebral artery occlusion (MCAO)-induced brain injury during late phases of neuronal cell death. Immediate early genes (IEGs) are induced by various forms of brain injury, and their induction is known to be a critical step in programmed cell death. The current study tested the hypothesis that the ability of estradiol to reduce MCAO-induced cell death involves attenuation of expression of one or more IEGs. We examined the effects of MCAO on the temporospatial pattern of IEG expression and the modulation of this pattern by estradiol replacement. Rats were ovariectomized and treated with either vehicle or low physiological concentrations of estradiol. One week later, rats underwent MCAO and brains were collected 1, 4, 8, 16, and 24 hr later. We assessed IEG mRNAs in discrete regions of brain by RT-PCR at 24 hr. We examined expression of c-Fos mRNA and protein in greater detail using in situ hybridization and immunohistochemistry to delineate the time course and specific regions of cortex in which estradiol influenced its expression. Our results reveal that c-fos, fosB, c-jun, and junB levels were upregulated at 24 hr. Furthermore, estradiol selectively affected the expression of c-Fos mRNA and protein by attenuating the injury-induced increase in a time- and region-specific manner. Our findings strongly suggest that the ability of estradiol to protect against MCAO-induced cell death involves attenuation of c-Fos induction.

Lifestyle-related risk factors for Parkinson's disease: a population-based study

OBJECTIVES

To investigate the association of major lifestyle-related risk factors with the prevalent cases of Parkinson's disease (PD) identified by the Italian Longitudinal Study on Aging.

METHODS

A total of 5632 individuals randomly selected from the population registers of eight centers were screened for parkinsonism using both a questionnaire and a neurologic examination. Screened positives underwent a structured clinical work-up for the diagnosis of parkinsonism and parkinsonism subtypes.

RESULTS

We identified 113 prevalent cases of PD. Age, male gender, and pesticide-use license were significantly related to PD. Heavy smoking was inversely related to PD. Age (OR = 1.1; 95% CI, 1.06-1.15) and pesticide-use license (OR = 3.7; 95% CI, 1.6-8.6) kept their significant correlation with the disease in the multivariate analysis to adjust for all the variables under investigation. Multivariate analyses were made for men and women separately: pesticide exposure was positively associated with PD only in men.

CONCLUSIONS

Pesticide exposure might represent a candidate for environmental factors involved in PD.

Dose- and sex-dependent effects of the neurotoxin 6-hydroxydopamine on the nigrostriatal dopaminergic pathway of adult rats: differential actions of estrogen in males and females

Epidemiological and clinical studies provide growing evidence for marked sex differences in the incidence of certain neurological disorders that are largely attributed to the neuroprotective effects of estrogen. Thus there is a keen interest in the clinical potential of estrogen-related compounds to act as novel therapeutic agents in conditions of neuronal injury and neurodegeneration such as Parkinson's disease. Studies employing animal models of neurodegeneration in ovariectomised female rats treated with estrogen support this hypothesis, yet experimental evidence for sex differences in the CNS response to direct neurotoxic insult is limited and, as yet, few studies have addressed the role played by endogenously produced hormones in neuroprotection. Therefore, in this study we aimed to determine (1) whether the prevailing levels of sex steroid hormones in the intact rat provide a degree of protection against neuronal assault in females compared with males and (2) whether sex differences depend solely on male/female differences in circulating estrogen levels or whether androgens could also play a role. Using the selective, centrally administered neurotoxin 6-hydroxydopamine, which induces a lesion in the nigrostriatal dopaminergic pathway similar to that seen in Parkinson's disease, we have demonstrated a sexually dimorphic (male-dominant), dose-dependent susceptibility in rats. Furthermore, following gonadectomy, dopamine depletion resulting from a submaximal dose of 6-hydroxydopamine (1 microg) was reduced in male rats, whereas in females, ovariectomy enhanced dopamine depletion. Administration of the nonaromatizable androgen dihydrotestosterone to gonadectomized animals had no significant effect on 6-hydroxydopamine toxicity in either males or females, whereas treatment of gonadectomized males and females with physiological levels of estrogen restored the extent of striatal dopamine loss to that seen in intact rats, viz, estrogen therapy reduced lesion size in females but increased it in males. Taken together, our findings strongly suggest that there are sex differences in the mechanisms whereby nigrostriatal dopaminergic neurones respond to injury. They also reveal that the reported clinically beneficial effects of estrogen in females may not be universally adopted for males. While the reasons for this gender-determined difference in response to the activational action of estrogen are unknown, we hypothesize that they may well be related to the early organizational events mediated by sex steroid hormones, which ultimately result in the sexual differentiation of the brain.

17beta-estradiol activates ICI 182,780-sensitive estrogen receptors and cyclic GMP-dependent thioredoxin expression for neuroprotection

Clinical studies suggest that estrogen may improve cognition in Alzheimer's patients. Basic experiments demonstrate that 17beta-estradiol protects against neurodegeneration in both cell and animal models. In the present study, a human SH-SY5Y cell model was used to investigate molecular mechanisms underlying the receptor-mediated neuroprotection of physiological concentrations of 17beta-estradiol. 17beta-estradiol (<10 nM) concomitantly increased neuronal nitric oxide synthase (NOS1) expression and cell viability. 17beta-estradiol-induced neuroprotection was blocked by the receptor antagonist ICI 182,780, also prevented by inhibitors of NOS1 (7-nitroindazole), guanylyl cyclase (LY 83,583), and cGMP-dependent protein kinase (PKG) (Rp-8-pCPT-cGMPs). In addition to the expression of NOS1 and MnSOD, 17beta-estradiol increased the expression of the redox protein thioredoxin (Trx), which was blocked by the inhibition of either cGMP formation or PKG activity. The expression of heme oxygenase 2 and brain-derived neurotrophic factor was not altered. Estrogen receptor-enhanced cell viability against oxidative stress may be linked to Trx expression because the Trx reductase inhibitor, 5,5'-dithio-bis(2-nitrobenzoic acid) significantly reduced the cytoprotective effect of 17beta-estradiol. Furthermore, Trx (1 microM) inhibited lipid peroxidation, proapoptotic caspase-3, and cell death during oxidative stress caused by serum deprivation. We conclude that cGMP-dependent expression of Trx--the redox protein with potent antioxidative and antiapoptotic properties--may play a pivotal role in estrogen-induced neuroprotection.

Estrogen receptor-mediated neuroprotection from oxidative stress requires activation of the mitogen-activated protein kinase pathway

It is well documented that estrogen mediates responses by both genomic and nongenomic mechanisms, both of which are important for cell survival. Because direct evidence showing that the estrogen receptors (ERs) alpha and/or beta can activate rapid signaling that may mediate neuroprotection is lacking, the hippocampal-derived cell line, HT22, was stably transfected with ERalpha (HTERalpha), ERbeta (HTERbeta), or a mutated form of ERalpha (HTERalphaHE27), which lacks the ability to mediate ER element-mediated transcription. Treatment of HT22, HTERalpha, HTERbeta, and HTERalphaHE27 cells with glutamate (5 mM) resulted in a significant decrease in cell viability. Pretreatment for 15 min with 10 nM 17beta-estradiol resulted in a 50% increase in the number of living cells in HTERalpha and HTERbeta cells but not in HT22 cells. The ER antagonist ICI 182,780 and the MEK inhibitor PD98059 prevented 17beta-estradiol-mediated protection. In HTERalphaHE27 cells, 17beta-estradiol rapidly phosphorylated ERK2 (within 15 min), in the absence of estrogen response element-mediated transcription. Treatment of HTERalphaHE27 cells with 10 nM 17beta-estradiol partially reversed the cell death produced by glutamate treatment. This study demonstrates that activation of either ERalpha or ERbeta can result in neuroprotection and that activation of the MAPK pathway is an important part of the neuroprotective mechanism.