Sex hormones and their impact on dementia and depression: a clinical perspective

Lung function impairment in relation to cognition and vascular brain lesions: the Rotterdam Study

OBJECTIVE

To investigate the association of chronic obstructive pulmonary disease (COPD) and Preserved Ratio Impaired Spirometry (PRISm) with cognitive performance and presence of vascular brain lesions (VBL).

METHODS

We determined both cross-sectional and longitudinal association of lung function impairment with cognition, as well as cross-sectional association of lung function impairment with VBL, in the general population. Between 2009 and 2014 we included 3,941 participants from the Rotterdam Study with spirometry tests, brain MRI scans and cognition tests, of whom 1815 had follow-up data on cognition.

RESULTS

Our finding indicated that cross-sectionally, participants with PRISm or COPD GOLD2-4 had a worse global cognitive performance. We did not find differences in cognition over time between those with normal spirometry versus those with lung function impairment. In addition, PRISm and COPD GOLD2-4 were associated with a higher prevalence of lacunar infarcts compared to normal spirometry.

CONCLUSIONS

This study suggests that persons with COPD GOLD2-4 or restrictive lung function, defined as PRISm, are characterized by poorer global cognitive function and a higher prevalence of lacunar infarcts.

Lung Function Impairment and the Risk of Incident Dementia: The Rotterdam Study

BACKGROUND

The etiology of dementia may partly be underpinned by impaired lung function via systemic inflammation and hypoxia.

OBJECTIVE

To prospectively examine the association between chronic obstructive pulmonary disease (COPD) and subclinical impairments in lung function and the risk of dementia.

METHODS

In the Rotterdam Study, we assessed the risk of incident dementia in participants with Preserved Ratio Impaired Spirometry (PRISm; FEV1/FVC≥0.7, FEV1 < 80% predicted) and in participants with COPD (FEV1/FVC < 0.7) compared to those with normal spirometry (controls; FEV1/FVC≥0.7, FEV1≥80% predicted). Hazard ratios (HRs) with 95% confidence intervals (CI) for dementia were adjusted for age, sex, education attainment, smoking status, systolic blood pressure, body mass index, triglycerides, comorbidities and Apolipoprotein E (APOE) genotype.

RESULTS

Of 4,765 participants, 110 (2.3%) developed dementia after 3.3 years. Compared to controls, participants with PRISm, but not COPD, had an increased risk for all-type dementia (adjusted HRPRISm 2.70; 95% CI, 1.53-4.75; adjusted HRCOPD 1.03; 95% CI, 0.61-1.74). These findings were primarily driven by men and smokers. Similarly, participants with FVC% predicted values in the lowest quartile compared to those in the highest quartile were at increased risk of all-type dementia (adjusted HR 2.28; 95% CI, 1.31-3.98), as well as Alzheimer's disease (AD; adjusted HR 2.13; 95% CI, 1.13-4.02).

CONCLUSION

Participants with PRISm or a low FVC% predicted lung function were at increased risk of dementia, compared to those with normal spirometry or a higher FVC% predicted, respectively. Further research is needed to elucidate whether this association is causal and how PRISm might contribute to dementia pathogenesis.

An association analysis between psychophysical characteristics and genome-wide gene expression changes in human adaptation to the extreme climate at the Antarctic Dome Argus

Genome-wide gene expression measurements have enabled comprehensive studies that integrate the changes of gene expression and phenotypic information to uncover their novel associations. Here we reported the association analysis between psychophysical phenotypes and genome-wide gene expression changes in human adaptation to one of the most extreme climates on Earth, the Antarctic Dome Argus. Dome A is the highest ice feature in Antarctica, and may be the coldest, driest and windiest location on earth. It is considered unapproachable due to its hostile environment. In 2007, a Chinese team of 17 male explorers made the expedition to Dome A for scientific investigation. Overall, 133 psychophysical phenotypes were recorded, and genome-wide gene expression profiles from the blood samples of the explorers were measured before their departure and upon their arrival at Dome A. We found that mood disturbances, including tension (anxiety), depression, anger and fatigue, had a strong, positive, linear relationship with the level of a male sex hormone, testosterone, using the Pearson correlation coefficient (PCC) analysis. We also demonstrated that significantly lowest-level Gene Ontology groups in changes of gene expression in blood cells with erythrocyte removal were consistent with the adaptation of the psychophysical characteristics. Interestingly, we discovered a list of genes that were strongly related to significant phenotypes using phenotype and gene expression PCC analysis. Importantly, among the 70 genes that were identified, most were significantly related to mood disturbances, where 42 genes have been reported in the literature mining, suggesting that the other 28 genes were likely novel genes involved in the mood disturbance mechanism. Taken together, our association analysis provides a reliable method to uncover novel genes and mechanisms related to phenotypes, although further studies are needed.

Hormone replacement therapy and physical function in healthy older men. Time to talk hormones?

Improving physical function and mobility in a continuously expanding elderly population emerges as a high priority of medicine today. Muscle mass, strength/power, and maximal exercise capacity are major determinants of physical function, and all decline with aging. This contributes to the incidence of frailty and disability observed in older men. Furthermore, it facilitates the accumulation of body fat and development of insulin resistance. Muscle adaptation to exercise is strongly influenced by anabolic endocrine hormones and local load-sensitive autocrine/paracrine growth factors. GH, IGF-I, and testosterone (T) are directly involved in muscle adaptation to exercise because they promote muscle protein synthesis, whereas T and locally expressed IGF-I have been reported to activate muscle stem cells. Although exercise programs improve physical function, in the long-term most older men fail to comply. The GH/IGF-I axis and T levels decline markedly with aging, whereas accumulating evidence supports their indispensable role in maintaining physical function integrity. Several studies have reported that the administration of T improves lean body mass and maximal voluntary strength in healthy older men. On the other hand, most studies have shown that administration of GH alone failed to improve muscle strength despite amelioration of the detrimental somatic changes of aging. Both GH and T are anabolic agents that promote muscle protein synthesis and hypertrophy but work through separate mechanisms, and the combined administration of GH and T, albeit in only a few studies, has resulted in greater efficacy than either hormone alone. Although it is clear that this combined approach is effective, this review concludes that further studies are needed to assess the long-term efficacy and safety of combined hormone replacement therapy in older men before the medical rationale of prescribing hormone replacement therapy for combating the sarcopenia of aging can be established.

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.

Preliminary investigation of plasma levels of sex hormones and human growth factor(s), and P300 latency as correlates to cognitive decline as a function of gender

Background

Aging is marked by declines in levels of many sex hormones and growth factors, as well as in cognitive function. The P300 event-related potential has been established as a predictor of cognitive decline. We decided to determine if this measure, as well as 2 standard tests of memory and attention, may be correlated with serum levels of sex hormones and growth factors, and if there are any generalizations that could be made based on these parameters and the aging process.

Findings

In this large clinically based preliminary study several sex-stratified associations between hormone levels and cognition were observed, including (1) for males aged 30 to 49, both IGF-1 and IGFBP-3 significantly associated negatively with prolonged P300 latency; (2) for males aged 30 to 49, the spearman correlation between prolonged P300 latency and low free testosterone was significant; (3) for males aged 60 to 69, there was a significant negative correlation between P300 latency and DHEA levels; (4) for females aged 50 to 59 IGFBP-3 significantly associated negatively with prolonged P300 latency; (5) for females at all age periods, estrogen and progesterone were uncorrelated with P300 latency; and (6) for females aged 40 to 69, there was significant negative correlation between DHEA levels and P300 latency. Moreover there were no statistically significant correlations between any hormone and Wechsler Memory Scale-III (WMS-111). However, in females, there was a significant positive correlation between estrogen levels and the number of Attention Deficit Disorder (ADD) complaints.

Conclusion

Given certain caveats including confounding factors involving psychiatric and other chronic diseases as well as medications, the results may still have important value. If these results could be confirmed in a more rigorously controlled investigation, it may have important value in the diagnosis, prevention and treatment of cognitive impairments and decline.

Neurobehavioral impact of menopause on mood

The menopausal transition is a time of risk for mood change ranging from distress to minor depression to major depressive disorder in a vulnerable subpopulation of women in the menopausal transition. Somatic symptoms have been implicated as a risk factor for mood problems, although these mood problems have also been shown to occur independently of somatic symptoms. Mood problems have been found to increase in those with a history of mood continuum disorders, but can also occur de novo as a consequence of the transition. Stress has been implicated in the etiology and the exacerbation of these mood problems. Estrogen and add-back testosterone have both been shown to positively affect mood and well-being. In most cases, the period of vulnerability to mood problems subsides when the woman's hormonal levels stabilize and she enters full menopause.

Cortisol, dehydroepiandrosterone, and estradiol measured over 24 hours in women with childhood sexual abuse-related posttraumatic stress disorder

Preclinical studies have shown long-term alterations in several hormonal systems including cortisol, dehydroepiandrosterone (DHEA) and DHEA-Sulfate, and estradiol. The purpose of this study was to assess cortisol, DHEA, and estradiol over a 24-hour period in women with early childhood sexual abuse and posttraumatic stress disorder (PTSD); with early abuse and without PTSD; and women without early abuse or PTSD. Forty-three women with early childhood sexual abuse and PTSD, early abuse without PTSD, and without abuse or PTSD, underwent a comprehensive assessment of hormones in plasma at multiple time points over a 24-hour period. Abused women with PTSD had lower concentrations of cortisol during the afternoon hours (12-8 p.m.) compared with women with abuse without PTSD and women without abuse or PTSD. DHEA-Sulfate was elevated throughout the 24-hour period in PTSD women, although this was of marginal statistical significance. There were no differences between groups in DHEA or estradiol. PTSD women also had increased cortisol pulsatility compared with the other groups. These findings suggest that a resting hypocortisolemia in the afternoon hours with increased cortisol pulsatility is associated with childhood abuse-related PTSD in women.

Plasma growth hormones, P300 event-related potential and test of variables of attention (TOVA) are important neuroendocrinological predictors of early cognitive decline in a clinical setting: evidence supported by structural equation modeling (SEM) parameter estimates

A review of the literature in both animals and humans reveals that changes in sex hormone have often been associated with changes in behavioral and mental abilities. Previously published research from our laboratory, and others, provides strong evidence that P300 (latency) event-related potential (ERP), a marker of neuronal processing speed, is an accurate predictor of early memory impairment in both males and females across a wide age range. It is our hypothesis, given the vast literature on the subject, that coupling growth hormones (insulin-like growth factor-I, (IGF-I) and insulin-like growth factor binding protein 3 (IGF-BP3)), P300 event-related potential and test of variables of attention (TOVA) are important neuroendocrinological predictors of early cognitive decline in a clinical setting. To support this hypothesis, we utilized structural equation modeling (SEM) parameter estimates to determine the relationship between aging and memory, as mediated by growth hormone (GH) levels (indirectly measured through the insulin-like growth factor system), P300 latency and TOVA, putative neurocognitive predictors tested in this study. An SEM was developed hypothesizing a causal directive path, leading from age to memory, mediated by IGF-1 and IGF-BP3, P300 latency (speed), and TOVA decrements. An increase in age was accompanied by a decrease in IGF-1 and IGF-BP3, an increase in P300 latency, a prolongation in TOVA response time, and a decrease in memory functioning. Moreover, independent of age, decreases in IGF-1 and IGF-BP3, were accompanied by increases in P300 latency, and were accompanied by increases in TOVA response time. Finally, increases in P300 latency were accompanied by decreased memory function, both directly and indirectly through mediation of TOVA response time. In summary, this is the first report utilizing SEM to reveal the finding that aging affects memory function negatively through mediation of decreased IGF-1 and IGF-BP3, and increased P300 latency (delayed attention and processing speed).

Estradiol effects on the dopamine transporter - protein levels, subcellular location, and function

Background

The effects of estrogens on dopamine (DA) transport may have important implications for the increased incidence of neurological disorders in women during life stages when hormonal fluctuations are prevalent, e.g. during menarche, reproductive cycling, pregnancy, and peri-menopause.

Results

The activity of the DA transporter (DAT) was measured by the specific uptake of ³H-DA. We found that low concentrations (10^-14 to 10^-8 M) of 17β-estradiol (E₂) inhibit uptake via the DAT in PC12 cells over 30 minutes, with significant inhibition taking place due to E₂ exposure during only the last five minutes of the uptake period. Such rapid action suggests a non-genomic, membrane-initiated estrogenic response mechanism. DAT and estrogen receptor-α (ERα) were elevated in cell extracts by a 20 ng/ml 2 day NGFβ treatment, while ERβ was not. DAT, ERα and ERβ were also detectable on the plasma membrane of unpermeabilized cells by immunocytochemical staining and by a fixed cell, quantitative antibody (Ab)-based plate assay. In addition, PC12 cells contained RNA coding for the alternative membrane ER GPR30; therefore, all 3 ER subtypes are candidates for mediating the rapid nongenomic actions of E₂. At cell densities above 15,000 cells per well, the E₂-induced inhibition of transport was reversed. Uptake activity oscillated with time after a 10 nM E₂ treatment; in a slower room temperature assay, inhibition peaked at 9 min, while uptake activity increased at 3 and 20–30 min. Using an Ab recognizing the second extracellular loop of DAT (accessible only on the outside of unpermeabilized cells), our immunoassay measured membrane vs. intracellular/nonvesicular DAT; both were found to decline over a 5–60 min E₂ treatment, though immunoblot analyses demonstrated no total cellular loss of protein.

Conclusion

Our results suggest that physiological levels of E₂ may act to sequester DAT in intracellular compartments where the transporter's second extramembrane loop is inaccessible (inside vesicles) and that rapid estrogenic actions on this differentiated neuronal cell type may be regulated via membrane ERs of several types.

A 20-week randomized controlled trial of estradiol replacement therapy for women aged 70 years and older: effect on mood, cognition and quality of life

The results of several observational studies suggest that the use of estrogen replacement is associated with better mood, cognitive function and quality of life. Such findings are consistent with those of laboratory-based research showing that estrogen promotes neuronal sprouting, enhances cholinergic activity in the brain, decreases brain and plasma levels of beta-amyloid, increases serotonin postsynaptic responsivity and the turnover of noradrenaline, and inhibits monoamine oxidase activity. However, the findings from the Women's Health Initiative controlled trial showed that hormone replacement (estrogen plus progestin) not only failed to improve mood, cognition and quality of life but also increased the risk of dementia. At present, there is limited information about the effect of unopposed estradiol replacement therapy (ERT) on the mental health outcomes of women at increased risk of cognitive decline (aged 70 years and over). We designed the present randomized, double-blind, placebo-controlled trial to clarify this issue. One hundred and fifteen women were randomized to treatment with estradiol (n=58; 2mg per day) or placebo for a total period of 20 weeks. The outcomes of interest in this study included changes in the Beck Depression Inventory (BDI) scores between baseline and week 20, as well as changes in quality of life scores (as measured by the SF-36) and cognitive function (CAMCOG, Block Design, Memory for Faces, California Verbal Learning Test (CVLT) and verbal fluency (VF)). Nineteen women treated with estradiol and 10 of those treated with placebo discontinued the use of the medication during trial, most frequently due to adverse reactions (OR=4.11, 95% CI=1.29-15.37). Intention-to-treat analysis showed that the active and placebo groups did not differ in their response to treatment in any of the outcome measures (p>0.05). A separate analysis restricted to women who completed the 20-week-trial produced similar negative results. The results of this trial indicate that the use of a relatively high dosage of unopposed estrogen replacement for 20 weeks is not associated with significant changes in cognitive function, mood and quality of life. Other more efficacious and safer interventions need to be devised with the aim of improving the mental state and quality of life of older women.

One year follow-up study of the association between chemical castration, sex hormones, beta-amyloid, memory and depression in men

The results of several recent studies suggest that estrogen and testosterone play an important role in the modulation of mood and cognitive function in women, and preliminary evidence indicates that these hormones may also modulate the levels of beta-amyloid (Abeta), a 4 Kilo Dalton peptide that is likely to be involved in the pathogenesis of Alzheimer's disease. However, the physiological and clinical effects of reversible castration remain unclear and no systematic data is currently available for men. We designed the present study to investigate the effects of reversible chemical castration on the mood and cognitive performance of men treated for prostate cancer, as well as its impact on the levels of plasma Abeta. Forty men with prostate cancer were clinically treated with androgen blockade therapy (flutamide and leuprolide) for 36 weeks and subsequently followed up for another 18 weeks after treatment was discontinued. All subjects received a comprehensive clinical, neuropsychological and biochemical evaluation that included the use of the Beck Depression (BDI) and Anxiety Inventories (BAI), several subtests of the Wechsler Memory and Intelligence Scales (Word Lists-WL, Verbal Paired Associates-VPA, Visual Reproduction-VR and Block Design-BD), and biochemical monitoring of changes in estrogen, testosterone and Abeta levels. Chemical castration was associated with a rapid and marked decline in the levels of testosterone and estradiol, and significant increase in plasma Abeta levels. Treatment was associated with increased BDI (p = 0.004) and BAI scores (p < 0.001), although such changes were of questionable clinical significance (i.e., few subjects had scores > or = 13). CAMCOG (p = 0.046) and WL recall total scores (p < 0.001) improved significantly after androgen blockade treatment was discontinued, but visuospatial abilities, as assessed by BD, was not influenced by the introduction or discontinuation of treatment. There was a significant negative correlation between changes in Abeta levels and subjects' WL total score change between weeks 36 and 54 (r = -0.452, p = 0.012). The results of this naturalistic study indicate that chemical castration is associated with a significant rise in the plasma levels of Abeta and, clinically, with increased depression and anxiety scores. The discontinuation of treatment is associated with better cognitive performance, most noticeably of verbal memory. The performance of subjects on the WL test was negatively correlated with plasma levels of Abeta, but the clinical significance of this finding remains to be determined.

Dehydroepiandrosterone upregulates neural androgen receptor level and transcriptional activity

The mechanism of action of dehydroepiandrosterone (DHEA), a neuroactive neurosteroid synthesized in the brains of humans and other mammals, has not been fully characterized in the adult brain. Although well known for modulatory effects on GABA(A), NMDA, and sigma(1) receptors, studies in both CNS and peripheral target cells suggest that DHEA also may exert genomic effects via the androgen receptor (AR). The current study tested the hypothesis that DHEA was capable of producing androgenic effects in the CNS by assaying its ability to induce three characteristic effects of an androgenic compound. These included the ability to upregulate neural AR protein level in mouse brain and immortalized GT1-7 hypothalamic cells, the capacity to induce transcriptional activity through AR in CV-1 cells transfected with an MMTV-ARE-CAT reporter, and competition for recombinant AR binding in a radioligand binding assay. The results showed that DHEA treatment significantly augmented AR both in vivo and in vitro, and that this effect was not blocked by trilostane (TRIL), a known 3beta-hydroxysteroid dehydrogenase (3beta-HSD) inhibitor. DHEA also promoted AR-mediated CAT reporter expression and competed with dihydrotestosterone (DHT) for binding to recombinant AR in a cell-free system. These data indicate that DHEA possesses intrinsic androgenic activity that is potentially independent of metabolic conversion to other androgens, and that it can affect gene function through the AR. In combination with its modulation of neurotransmitter receptors at the cell membrane level, the findings suggest that the mechanism of action of DHEA in the brain can involve a "crosstalk" cellular signaling system that involves both nongenomic and genomic components.

Can testosterone replacement decrease the memory problem of old age?

The world is rapidly ageing. It is against this backdrop that there are increasing incidences of dementia reported worldwide, with Alzheimer's disease (AD) being the most common form of dementia in the elderly. It is estimated that AD affects almost 4 million people in the US, and costs the US economy more than 65 million dollars annually. There is currently no cure for AD but various therapeutic agents have been employed in attempting to slow down the progression of the illness, one of which is oestrogen. Over the last decades, scientists have focused mainly on the roles of oestrogen in the prevention and treatment of AD. Newer evidences suggested that testosterone might also be involved in the pathogenesis of AD. Although the exact mechanisms on how androgen might affect AD are still largely unknown, it is known that testosterone can act directly via androgen receptor-dependent mechanisms or indirectly by converting to oestrogen to exert this effect. Clinical trials need to be conducted to ascertain the putative role of androgen replacement in Alzheimer's disease.

Efficacy of pharmacological treatment of dementia

Over the last 25 years an increasing number of studies have been performed to evaluate therapeutic agents for people with dementia. Although numerous agents have been trialed at this stage there little evidence that therapeutic agents can prevent dementia or ameliorate the progression of dementia of any type. There is some evidence that specific medical management in high risk individuals can prevent strokes, and thus probably prevent vascular dementia, although this is extrapolating from the available evidence. There is considerable evidence that cholinesterase inhibitor are effective for cognitive symptoms in people with mild to moderate AD, and there is some evidence that they are also effective for other behavioural and functional symptoms. The currently available cholinesterase inhibitors seem to have approximately the same sized effect and thus the choice of agent may be largely determined by the incidence of side-effects. These agents have modest effects and a cautious therapeutic trial is indicated for those subjects with mild to moderate AD.