Pineal and pituitary-adrenocortical function in physiological aging and in senile dementia

The role of plasma cortisol in dementia, epilepsy, and multiple sclerosis: A Mendelian randomization study

BACKGROUND

Many clinical studies have shown a correlation between plasma cortisol and neurological disorders. This study explored the causal relationship between plasma cortisol and dementia, epilepsy and multiple sclerosis based on Mendelian randomization (MR) method.

METHODS

Data were taken from the summary statistics of a genome-wide association study, FinnGen consortium and United Kingdom Biobank. Dementia, epilepsy, and multiple sclerosis were used as outcomes, and genetic variants associated with plasma cortisol were used as instrumental variables. The main analysis was performed using the inverse variance weighted method, and the results were assessed according to the odds ratio (OR) and 95% confidence interval. Heterogeneity tests, pleiotropy tests, and leave-one-out method were conducted to evaluate the stability and accuracy of the results.

RESULTS

In two-sample MR analysis, the inverse variance weighted method showed that plasma cortisol was associated with Alzheimer's disease (AD) [odds ratio (95% confidence interval) = 0.99 (0.98-1.00), P = 0.025], vascular dementia (VaD) [odds ratio (95% confidence interval) = 2.02 (1.00-4.05), P = 0.049)], Parkinson's disease with dementia (PDD) [odds ratio (95% confidence interval) = 0.24 (0.07-0.82), P = 0.023] and epilepsy [odds ratio (95% confidence interval) = 2.00 (1.03-3.91), P = 0.042]. There were no statistically significant associations between plasma cortisol and dementia with Lewy bodies (DLB), frontotemporal dementia (FTD) and multiple sclerosis.

CONCLUSION

This study demonstrates that plasma cortisol increase the incidence rates of epilepsy and VaD and decrease the incidence rates of AD and PDD. Monitoring plasma cortisol concentrations in clinical practice can help prevent diseases, such as AD, PDD, VaD and epilepsy.

Aging in the sebaceous gland

Sebaceous glands (SGs) originate from hair follicular stem cells and secrete lipids to lubricate the skin. The coordinated effects of intrinsic and extrinsic aging factors generate degradation of SGs at a late age. Senescence of SGs could be a mirror of the late aging of both the human body and skin. The procedure of SG aging goes over an initial SG hyperplasia at light-exposed skin areas to end with SG atrophy, decreased sebum secretion, and altered sebum composition, which is related to skin dryness, lack of brightness, xerosis, roughness, desquamation, and pruritus. During differentiation and aging of SGs, many signaling pathways, such as Wnt/β-catenin, c-Myc, aryl hydrocarbon receptor (AhR), and p53 pathways, are involved. Random processes lead to random cell and DNA damage due to the production of free radicals during the lifespan and neuroendocrine system alterations. Extrinsic factors include sunlight exposure (photoaging), environmental pollution, and cigarette smoking, which can directly activate signaling pathways, such as Wnt/β-catenin, Notch, AhR, and p53 pathways, and are probably associated with the de-differentiation and hyperplasia of SGs, or indirectly activate the abovementioned signaling pathways by elevating the inflammation level. The production of ROS during intrinsic SG aging is less, the signaling pathways are activated slowly and mildly, and sebocytes are still differentiated, yet terminal differentiation is not completed. With extrinsic factors, relevant signaling pathways are activated rapidly and fiercely, thus inhibiting the differentiation of progenitor sebocytes and even inducing the differentiation of progenitor sebocytes into keratinocytes. The management of SG aging is also mentioned.

Melatonin profile in healthy, elderly subjects - A systematic literature review

Melatonin plays an important role in regulation and maintaining of the circadian rhythm. In the elderly population, an array of disturbances of circadian rhythm and sleep can be observed; however the current knowledge within the group of healthy, elderly is scarce. This systematic literature review of studies on the melatonin profile measured in the blood of healthy, elderly individuals included 519 studies, found in the primary search on PubMed. After reviewing the title and abstract, 47 studies were found eligible for full text review. The inclusion criteria were defined as follows: healthy, elderly individuals, with a mean or average age over 65 years and analysis done in blood or plasma. In addition to the primary search, three studies were directly identified by the reference lists of already included studies. A final total of 23 studies were included in the systematic literature review. In reviewing the literature, a clear circadian melatonin profile with a nocturnal peak at 3 am and lower daytime levels was observed in the healthy, elderly population. In elderly over 75 years of age, the nocturnal level of melatonin may be lower; however, the circadian rhythmicity is maintained. In the comparison of elderly, independently living individuals and individuals living in care facilities, the latter group had lower levels of nocturnal melatonin peak as well as higher daytime levels; however one can wonder if elderly in care facilities are healthy. The 23 included studies in the systematic literature review had varying primary objectives and generally the term "healthy" within this population group proves difficult to clearly define. As a result of this, an obvious interstudy variability existed, which is a limitation of this systematic literature review. However, the graphs depicted represent the best possible estimation of the melatonin profile in a healthy, elderly population. Future research in the melatonin profile within this population should focus on clearly defined healthy elderly to ensure a valid normal material in this age group.

Intact circadian rhythm despite cortisol hypersecretion in Alzheimer's disease: A meta-analysis

Hypersecretion of the glucocorticoid steroid hormone cortisol by individuals with Alzheimer's disease (AD) has been suspected for several decades, during which time dozens of examinations of this phenomenon have been conducted and published. The goals of this investigation were to summarize this sizeable body of literature, test whether participant and methodological characteristics modify the magnitude of the AD-associated basal cortisol hypersecretion, and examine whether cortisol circadian rhythmicity is maintained among individuals with AD. To this end, the present meta-analysis and systematic review examined over 300 comparisons of indices of basal HPA-axis functioning between individuals with AD and cognitively normal older adults. AD was associated with basal cortisol elevations (g = 0.45) but the magnitude of the effect was not systematically impacted by any of the participant characteristics considered or the time-of-day of the cortisol sampling. Further, there was no evidence of group differences among direct indices of circadian rhythmicity such as the cortisol awakening response or the diurnal cortisol slope. These results suggest that basal hypersecretion of cortisol, but not circadian dysrhythmia, is characteristic of individuals with AD. Mechanistically, the observed hypersecretion is consistent with the theorized AD-driven deterioration of the hippocampus and subsequent reduction in hypothalamic-pituitary-adrenal axis inhibition. Further investigation is warranted to elucidate the role and timing of cortisol elevations in the progression of AD.

Serum Daytime Melatonin Levels Reflect Cerebrospinal Fluid Melatonin Levels in Alzheimer's Disease but Are Not Correlated with Cognitive Decline

Background:

Nocturnal cerebrospinal fluid (CSF) and blood melatonin levels are altered in Alzheimer’s disease (AD). However, literature remains inconclusive on daytime blood melatonin levels. A positive correlation between melatonin levels and Mini-Mental State Examination (MMSE) scores in AD subjects has been evidenced following cross-sectional analyses. Whereas a correlation between serum and spinal CSF melatonin has been shown in healthy volunteers, an equal investigation in AD patients still has to be undertaken.

Objective:

1) To evaluate whether serum melatonin levels correlate with spinal CSF melatonin levels in AD. 2) To compare daytime CSF and serum melatonin levels between patients with AD dementia, mild cognitive impairment due to AD, and healthy controls, and to evaluate whether melatonin can affect cognitive decline in AD.

Methods:

Subjects with AD and healthy controls included in two existing cohorts, of whom a CSF and serum sample was available at the neurobiobank and had at least 6 months of neuropsychological follow-up, were included in the present study. Melatonin concentrations were measured with liquid chromatography-mass spectrometry.

Results:

Daytime serum melatonin levels correlated with spinal CSF melatonin levels in AD (r = 0.751, p < 0.001). No significant differences regarding daytime melatonin levels were found between patients and controls. No correlations were observed between daytime melatonin levels and MMSE score changes.

Conclusion:

Daytime serum melatonin accurately reflects CSF melatonin levels in AD, raising the possibility to assess melatonin alterations by solely performing blood sampling if also confirmed for night-time values. However, daytime melatonin levels are not associated with changes of cognitive impairment.

Melatonin levels in the Alzheimer's disease continuum: a systematic review

Background

The search for new Alzheimer’s disease (AD) cerebrospinal fluid (CSF) and blood biomarkers with potential pathophysiological and clinical relevance continues, as new biomarkers might lead to improved early and differential diagnosis, monitoring of disease progression and might even identify new druggable targets. Melatonin might be an interesting biomarker as an inverse correlation between CSF melatonin levels, and severity of the neuropathology as measured by Braak stages has been described. Melatonin can be measured in different body fluids, such as CSF, blood, saliva and urine.

Objectives

The aim of this systematic review was to review all available studies regarding melatonin levels in different body fluids in the AD continuum and give an extensive overview of reported outcomes.

Methods

We included papers comparing melatonin levels between healthy controls and human patients belonging to the AD continuum. A systematic search of PubMed and Web of Science led to inclusion of 20 full-length English papers following exclusion of duplicates.

Results

This systematic literature search showed that disruptions in melatonin levels occur with age, but also in AD when compared to age-matched controls. Night-time melatonin levels were found to be lower in CSF and blood of AD patients as compared to controls. Literature was not conclusive regarding alterations in blood daytime melatonin levels or regarding saliva melatonin in AD patients. Decreased total and night-time melatonin production has been described in urine of AD patients.

Conclusion

Our systematic review shows evidence for disruptions in (night-time) melatonin levels in AD as compared to age-matched controls. Although more studies are needed to understand the contribution of disruption of the melatonergic system to the pathophysiology of AD, the potential anti-AD effects that have been attributed to melatonin, renders research on this topic relevant for the discovery of potential future treatment effects of melatonin for AD. The use of melatonin as potential blood biomarker for disease progression should also be further investigated.

Melatonin directly binds and inhibits death-associated protein kinase 1 function in Alzheimer's disease

Death-associated protein kinase 1 (DAPK1) is upregulated in the brains of human Alzheimer's disease (AD) patients compared with normal subjects, and aberrant DAPK1 regulation is implicated in the development of AD. However, little is known about whether and how DAPK1 function is regulated in AD. Here, we identified melatonin as a critical regulator of DAPK1 levels and function. Melatonin significantly decreases DAPK1 expression in a post-transcriptional manner in neuronal cell lines and mouse primary cortical neurons. Moreover, melatonin directly binds to DAPK1 and promotes its ubiquitination, resulting in increased DAPK1 protein degradation through a proteasome-dependent pathway. Furthermore, in tau-overexpressing mouse brain slices, melatonin treatment and the inhibition of DAPK1 kinase activity synergistically decrease tau phosphorylation at multiple sites related to AD. In addition, melatonin and DAPK1 inhibitor dramatically accelerate neurite outgrowth and increase the assembly of microtubules. Mechanistically, melatonin-mediated DAPK1 degradation increases the activity of Pin1, a prolyl isomerase known to play a protective role against tau hyperphosphorylation and tau-related pathologies. Finally, elevated DAPK1 expression shows a strong correlation with the decrease in melatonin levels in human AD brains. Combined, these results suggest that DAPK1 regulation by melatonin is a novel mechanism that controls tau phosphorylation and function and offers new therapeutic options for treating human AD.

On the Etiopathogenesis and Pathophysiology of Alzheimer's Disease: A Comprehensive Theoretical Review

Alzheimers' disease (AD) is the most common cause of dementia, with an estimated 5 million new cases occurring annually. Among the elderly, AD shortens life expectancy, results in disability, decreases quality of life, and ultimately, leads to institutionalization. Despite extensive research in the last few decades, its heterogeneous pathophysiology and etiopathogenesis have made it difficult to develop an effective treatment and prevention strategy. Aging is the biggest risk factor for AD and evidence suggest that the total number of older people in the population is going to increase astronomically in the next decades. Also, there is evidence that air pollution and increasing income inequality may result in higher incidence and prevalence of AD. This makes the need for a comprehensive understanding of the etiopathogenesis and pathophysiology of the disease extremely critical. In this paper, a quintuple framework of thyroid dysfunction, vitamin D deficiency, sex hormones, and mitochondria dysfunction and oxidative stress are used to provide a comprehensive description of AD etiopathogenesis and pathophysiology. The individual role of each factor, their synergistic and genetic interactions, as well as the limitations of the framework are discussed.

Multiple Causes of Dementia as Engineered Senescence

All traumas—cranial, cardiovascular, hormone, viral, bacterial, fungi, parasites, misfolded protein, genetic, behavior, environmental and medication—affect the brain. This paper itemizes studies showing the many different causes of dementia including Alzheimer’s disease. Causes interact with each other, act sequentially by preparing the optimal conditions for its successor, initiate other diseases, allow for other traumas to accumulate and degrade protective features of the brain. Since such age-related cognitive impairment is not exclusively a human attribute there might be support for an evolutionary theory of dementia. Relying on theories of antagonistic pleiotropy and polymorphism, the brain has been designed to sequester trauma. Because of increased longevity, the short-term tactic of sequestering trauma becomes a long-term liability. We are engineered to sequester these insults until a tipping point is reached. Dementia is an evolutionary trade-off for longevity. We cannot cure dementia without understanding the overall biology of aging.

Pineal gland dysfunction in Alzheimer's disease: relationship with the immune-pineal axis, sleep disturbance, and neurogenesis

Alzheimer’s disease (AD) is a globally common neurodegenerative disease, which is accompanied by alterations to various lifestyle patterns, such as sleep disturbance. The pineal gland is the primary endocrine organ that secretes hormones, such as melatonin, and controls the circadian rhythms. The decrease in pineal gland volume and pineal calcification leads to the reduction of melatonin production. Melatonin has been reported to have multiple roles in the central nervous system (CNS), including improving neurogenesis and synaptic plasticity, suppressing neuroinflammation, enhancing memory function, and protecting against oxidative stress. Recently, reduced pineal gland volume and pineal calcification, accompanied by cognitive decline and sleep disturbances have been observed in AD patients. Here, I review current significant evidence of the contribution of pineal dysfunction in AD to the progress of AD neuropathology. I suggest new insights to understanding the relationship between AD pathogenesis and pineal gland function.

On the central role of mitochondria dysfunction and oxidative stress in Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is the commonest cause of dementia, with approximately 5 million new cases occurring annually. Despite decades of research, its complex pathophysiology and etiopathogenesis presents a major hindrance to the development of an effective treatment and prevention strategy. Aging is the biggest risk factor for the development of AD, and the total number of older people in the population is going to significantly increase in the next decades, suggesting that AD incidence and prevalence is likely to increase in the future. This makes the need for a better understanding of the disease to be extremely urgent.

METHODS

A search was done by accessing PubMed/Medline, EBSCO, and PsycINFO databases. The search string used was "(dementia* OR Alzheimer's) AND (pathophysiology* OR pathogenesis)". New key terms were identified (new term included "vitamin D, thyroid hormone, mitochondria dysfunction, oxidative stress, testosterone, estrogen, melatonin, progesterone, luteinizing hormone, amyloid-β (Aβ), and hyperphosphorylated tau"). The electronic databases were searched for titles or abstracts containing these terms in all published articles between January 1, 1965, and January 31, 2019. The search was limited to studies published in English and other languages involving both animal and human subjects.

RESULTS

Mitochondria dysfunction and oxidative stress play a critical role in AD etiopathogenesis and pathophysiology.

CONCLUSION

AD treatment and prevention strategies must be geared towards improving mitochondrial function and attenuating oxidative stress.

Dehydroepiandrosterone and Dehydroepiandrosterone Sulfate in Alzheimer's Disease: A Systematic Review and Meta-Analysis

Background and Purpose: Previous studies found inconsistent results for the relationship between Alzheimer's disease and the levels of dehydroepiandrosterone and dehydroepiandrosterone sulfate. This study performed a systematic review and meta-analysis to evaluate previous studies' results on this relationship. Method: Studies related to this outcome were obtained using a systematic search from the electronic databases of PubMed, Embase, Web of Science, and Psyc-ARTICLES in March 2018. The random-effects model was used to measure the strength of the association between Alzheimer's disease and the levels of dehydroepiandrosterone and dehydroepiandrosterone sulfate, using the standardized mean difference. Results: Thirty-one eligible studies were included in the final analysis. There was no statistically significant association between the level of dehydroepiandrosterone and Alzheimer's disease (standardized mean difference: 0.51, 95% confidence interval: -0.44 to 1.45, Z = 1.06, p = 0.29). On the other hand, lower level dehydroepiandrosterone sulfate was observed in patients with Alzheimer's disease than in controls (standardized mean difference: -0.69, 95% confidence interval: -1.17 to -0.22, Z = -2.84, p < 0.01). Conclusion: Decreased dehydroepiandrosterone sulfate concentrations may be an important indicator for Alzheimer's disease, although whether dehydroepiandrosterone sulfate could be used as a diagnostic tool requires further research.

A High Serum Cortisol/DHEA-S Ratio Is a Risk Factor for Sarcopenia in Elderly Diabetic Patients

Context

Elderly patients with type 2 diabetes mellitus (T2DM) have a high prevalence of frailty and/or sarcopenia. Sarcopenia is thought to be related to discordant secretions of the adrenal hormones cortisol and dehydroepiandrosterone (DHEA), as well as the sulfate ester of DHEA (DHEA-S). The current study sought to evaluate the risk factors for sarcopenia in elderly patients with T2DM.

Design and Patients

We enrolled 108 consecutive elderly patients aged ≥65 years with T2DM (mean age, 76.2 ± 7.3 years; 43.5% males). Sarcopenia was assessed and diagnosed based on the Asian version of the diagnostic criteria regarding muscular strength, physical function, and muscle mass. We assessed various physical parameters, blood tests, and atherosclerosis markers and statistically determined the risk factors for sarcopenia.

Results

Multiple regression analysis showed that the independent risk factors for sarcopenia were a serum cortisol/DHEA-S ratio ≥0.2, diastolic blood pressure <70 mm Hg, Hb concentration <13 g/dL, and an ankle brachial index <1.0. The strongest risk factor for sarcopenia was a serum cortisol/DHEA-S ratio ≥0.2. An increase in the serum cortisol/DHEA-S ratio reflected higher cortisol values and lower DHEA-S values in patients with sarcopenia compared with those in nonsarcopenic patients. The concentrations of cortisol and DHEA-S, as well as the cortisol/DHEA-S ratio, changed in accordance with the severity of sarcopenia.

Conclusions

A relative increase in cortisol may reflect the presence of stress and stimulate muscle catabolism, whereas a relative decrease in DHEA-S may cause a decrease in the anabolic action of DHEA on muscle; the combination of these factors may lead to sarcopenia.

Monoamines and their Derivatives on GPCRs: Potential Therapy for Alzheimer's Disease

Albeit cholinergic depletion remains the key event in Alzheimer's Disease (AD), recent information describes stronger links between monoamines (trace amines, catecholamines, histamine, serotonin, and melatonin) and AD than those known in the past century. Therefore, new drug design strategies focus efforts to translate the scope on these topics and to offer new drugs which can be applied as therapeutic tools in AD. In the present work, we reviewed the state-of-art regarding genetic, neuropathology and neurochemistry of AD involving monoamine systems. Then, we compiled the effects of monoamines found in the brain of mammals as well as the reported effects of their derivatives and some structure-activity relationships. Recent derivatives have triggered exciting effects and pharmacokinetic properties in both murine models and humans. In some cases, the mechanism of action is clear, essentially through the interaction on G-protein-coupled receptors as revised in this manuscript. Additional mechanisms are inhibition of enzymes for their biotransformation, regulation of free-radicals in the central nervous system and others for the effects on Tau phosphorylation or amyloid-beta accumulation. All these data make the monoamines and their derivatives attractive potential elements for AD therapy.

The physiology of endocrine systems with ageing

During ageing, the secretory patterns of the hormones produced by the hypothalamic-pituitary axis change, as does the sensitivity of the axis to negative feedback by end hormones. Additionally, glucose homoeostasis tends towards disequilibrium with increasing age. Along with these endocrine alterations, a loss of bone and muscle mass and strength occurs, coupled with an increase in fat mass. In addition, ageing-induced effects are difficult to disentangle from the influence of other factors that are common in older people, such as chronic diseases, inflammation, and low nutritional status, all of which can also affect endocrine systems. Traditionally, the decrease in hormone activity during the ageing process has been considered to be detrimental because of the related decline in bodily functions. The concept of hormone replacement therapy was suggested as a therapeutic intervention to stop or reverse this decline. However, clearly some of these changes are a beneficial adaptation to ageing, whereas hormonal intervention often causes important adverse effects. In this paper, we discuss the effects of age on the different hypothalamic-pituitary-hormonal organ axes, as well as age-related changes in calcium and bone metabolism and glucose homoeostasis.

ATP-sensitive potassium-channel inhibitor glibenclamide attenuates HPA axis hyperactivity, depression- and anxiety-related symptoms in a rat model of Alzheimer's disease

Affective disorders including depression and anxiety are among the most prevalent behavioral abnormalities in patients with Alzheimer's disease (AD), which affect the quality of life and progression of the disease. Dysregulation of the hypothalamic-pituitary-adrenal-(HPA) axis has been reported in affective disorders and AD. Recent studies revealed that current antidepressant drugs are not completely effective for treating anxiety- and depression-related disorders in people with dementia. ATP-sensitive-potassium-(K_ATP) channels are well-known to be involved in AD pathophysiology, HPA axis function and the pathogenesis of depression and anxiety-related behaviors. Thus, targeting of K_ATP channel may be a potential therapeutic strategy in AD. Hence, we investigated the effects of intracerebroventricular injection of Aβ25-35 alone or in combination with glibenclamide, K_ATP channel inhibitor on depression- and anxiety-related behaviors as well as HPA axis response to stress in rats. To do this, non-Aβ25-35- and Aβ25-35-treated rats were orally treated with glibenclamide, then the behavioral consequences were assessed using sucrose preference, forced swim, light-dark box and plus maze tests. Stress-induced corticosterone levels following forced swim and plus maze tests were also evaluated as indicative of abnormal HPA-axis-function. Aβ25-35 induced HPA axis hyperreactivity and increased depression- and anxiety-related symptoms in rats. Our results showed that blockade of K_ATP channels with glibenclamide decreased depression- and anxiety-related behaviors by normalizing HPA axis activity in Aβ25-35-treated rats. This study provides additional evidence that Aβ administration can induce depression- and anxiety-like symptoms in rodents, and suggests that K_ATP channel inhibitors may be a plausible therapeutic strategy for treating affective disorders in AD patients.

Mechanisms of Melatonin in Alleviating Alzheimer's Disease

Alzheimer's disease (AD) is a chronic, progressive and prevalent neurodegenerative disease characterized by the loss of higher cognitive functions and an associated loss of memory. The thus far "incurable" stigma for AD prevails because of variations in the success rates of different treatment protocols in animal and human studies. Among the classical hypotheses explaining AD pathogenesis, the amyloid hypothesis is currently being targeted for drug development. The underlying concept is to prevent the formation of these neurotoxic peptides which play a central role in AD pathology and trigger a multispectral cascade of neurodegenerative processes post-aggregation. This could possibly be achieved by pharmacological inhibition of β- or γ-secretase or stimulating the nonamyloidogenic α-secretase. Melatonin the pineal hormone is a multifunctioning indoleamine. Production of this amphiphilic molecule diminishes with advancing age and this decrease runs parallel with the progression of AD which itself explains the potential benefits of melatonin in line of development and devastating consequences of the disease progression. Our recent studies have revealed a novel mechanism by which melatonin stimulates the nonamyloidogenic processing and inhibits the amyloidogenic processing of β-amyloid precursor protein (βAPP) by stimulating α -secretases and consequently down regulating both β- and γ-secretases at the transcriptional level. In this review, we discuss and evaluate the neuroprotective functions of melatonin in AD pathogenesis, including its role in the classical hypotheses in cellular and animal models and clinical interventions in AD patients, and suggest that with early detection, melatonin treatment is qualified to be an anti-AD therapy.

Age-related desynchronosis in primary open-angle glaucoma patients: cause or consequence? Correction possibilities

Purpose of this investigation was to study the circadian biologic rhythm dysregulation of intraocular pressure (IOP), blood pressure (BP), and heart rate (HR) in primary open-angle glaucoma (POAG) patients of different age groups. Objectives: to reveal the desynchronosis pattern of biologic rhythm parameters in POAG patients, to study the influence of peptide bioregulatory complex on the synchronization of chosen parameters, to investigate correction possibilities from the perspective of the optic nerve tolerance enhancement, ischemia decrease and ocular perfusion improvement.Materials and methods. At the first stage, we performed a representative selection of patients with BP, HR and IOP dysregulation among POAG patients and subjects without glaucoma of corresponding age (n = 330). For mathematic justification of the desynchronosis identification, we used cosinor-analysis of circadian changes of functional indices. At the second stage, we performed a randomized study with parallel comparison groups masked for the investigator estimating the results. Patients with revealed desynchronosis (n = 56) were randomly divided into two groups for comparison. The main group consisted of 27 patients who, in addition to systemic and local pressure-lowering therapy, received 1 tablet of epifamin (Longvi-Farm, Russia) 3 times a day for 30 days; сortexin (Geropharm, Russia) 10 mg daily for 10 days; retinalamin (Geropharm, Russia) 5 mg daily as peribulbar injections for 10 days. 29 control group patients received traditional treatment (vitamins, spasmolytics, antioxydants) together with local and systemic pressure-lowering therapy. In compared groups, we calculated the tolerant pressure level, investigated the dynamics of retinal sensitivity mean deviation (MD), registrated the oscillatory potentials (OP) with the OP index calculation.Results. In elderly patients with glaucoma, significant changes of the temporal order of physiological parameters were found (deviation of IOP daily rhythm curves, systolic blood pressure (SBP), diastolic blood pressure (DBP), and hemodynamic indices).Conclusion. Through hemodynamic, nootropic, neurotrophic effects of the investigated bioregulatory peptide complex, the optic nerve tolerance to the stress influence of IOP, SBP and DBP asynchronous fluctuations increased, and ocular perfusion enhanced.

The Synergistic Relationship between Alzheimer's Disease and Sleep Disorders: An Update

Sleep disorders are frequently reported in Alzheimer's disease (AD), with a significant impact on patients and caregivers and a major risk factor for early institutionalization. Although changes in sleep organization are a hallmark of the normal aging processes, sleep macro- and micro-architectural alterations are more evident in patients affected by AD. Degeneration of neural pathways regulating sleep-wake patterns and sleep architecture may contribute to sleep alterations. In return, several recent studies suggested that common sleep disorders may precede clinical symptoms of dementia and represent risk factors for cognitive decline, through impairment of sleep-dependent memory consolidation processes. Thus, a close relationship between sleep disorders and AD has been largely hypothesized. Here, sleep alterations in AD and its pre-dementia stage, mild cognitive impairment, and their complex interactions are reviewed.

Depression as a risk factor for Alzheimer's disease: Genes, steroids, cytokines and neurogenesis - What do we need to know?

Depression (MDD) is prodromal to, and a component of, Alzheimer's disease (AD): it may also be a trigger for incipient AD. MDD is not a unitary disorder, so there may be particular subtypes of early life MDD that pose independent high risks for later AD, though the identification of these subtypes is problematical. There may either be a common pathological event underlying both MDD and AD, or MDD may sensitize the brain to a second event ('hit') that precipitates AD. MDD may also accelerate brain ageing, including altered DNA methylation, increased cortisol but decreasing DHEA and thus the risk for AD. So far, genes predicting AD (e.g. APOEε4) are not risk factors for MDD, and those implicated in MDD (e.g. SLC6A4) are not risks for AD, so a common genetic predisposition looks unlikely. There is as yet no strong indication that an epigenetic event occurs during some forms of MDD that predisposes to later AD, though the evidence is limited. Glucocorticoids (GCs) are disturbed in some cases of MDD and in AD. GCs have marked degenerative actions on the hippocampus, a site of early β-amyloid deposition, and rare genetic variants of GC-regulating enzymes (e.g. 11β-HSD) predispose to AD. GCs also inhibit hippocampal neurogenesis and plasticity, and thus episodic memory, a core symptom of AD. Disordered GCs in MDD may inhibit neurogenesis, but the contribution of diminished neurogenesis to the onset or progression of AD is still debated. GCs and cytokines also reduce BDNF, implicated in both MDD and AD and hippocampal neurogenesis, reinforcing the notion that those cases of MDD with disordered GCs may be a risk for AD. Cytokines, including IL1β, IL6 and TNFα, are increased in the blood in some cases of MDD. They also reduce hippocampal neurogenesis, and increased cytokines are a known risk for later AD. Inflammatory changes occur in both MDD and AD (e.g. raised CRP, TNFα). Both cytokines and GCs can have pro-inflammatory actions in the brain. Inflammation (e.g. microglial activation) may be a common link, but this has not been systematically investigated. We lack substantial, rigorous and comprehensive follow-up studies to better identify possible subtypes of MDD that may represent a major predictor for later AD. This would enable specific interventions during critical episodes of these subtypes of MDD that should reduce this substantial risk.

Melatonin and cortisol profiles in late midlife and their association with age-related changes in cognition

Previous studies have reported an association between circadian disturbances and age-related cognitive impairment. The aim was to study the 24-hour profiles of melatonin and cortisol in relation to cognitive function in middle-aged male subjects. Fifty healthy middle-aged males born in 1953 were recruited from a population-based cohort based on previous cognitive assessments in young adulthood and late midlife. The sample included 24 cognitively high-functioning and 26 cognitively impaired participants. Saliva samples were collected every 4 hours over a 24-hour period and analyzed for cortisol and melatonin levels by immunoassay. All participants exhibited clear circadian rhythms of salivary melatonin and cortisol. Salivary melatonin concentrations had a nocturnal peak at approximately 4 am. The median nocturnal melatonin response at 4 am was significantly lower in the cognitively impaired group than in the high-functioning group (-4.6 pg/mL, 95% CI: -7.84, -1.36, P=0.006). The 24-hour mean melatonin concentration (high-functioning group: 4.80±0.70 pg/mL, vs cognitively impaired group: 4.81±0.76 pg/mL; P>0.05) (or the area under the curve, AUC) was not significantly different between the two groups. Cortisol levels were low during the night, and peaked at approximately 8 am. Median cortisol concentrations were similar at all times, as were the 24-hour mean cortisol concentrations and AUC. To the best of our knowledge, ours is the first study to assess circadian measures (ie, melatonin and cortisol) in healthy middle-aged men with different cognitive trajectories in midlife. We found evidence of altered circadian rhythms with a reduced nocturnal melatonin response at 4 am in men with cognitive impairment. The 24-hour concentration and AUC of melatonin and cortisol were similar in the cognitively high-functioning group and in the cognitively impaired.

Cortisol levels and suicidal behavior: A meta-analysis

Suicide is a major cause of death worldwide, responsible for 1.5% of all mortality. The causes of suicidal behavior are not fully understood. Dysregulated hypothalamic-pituitary-adrenal (HPA) axis activity, as measured by cortisol levels, is one potential risk factor. This meta-analytic review aimed (i) to estimate the strength and variability of the association between naturally fluctuating cortisol levels and suicidal behavior and (ii) to identify moderators of this relationship. A systematic literature search identified 27 studies (N=2226; 779 suicide attempters and 1447 non-attempters) that met the study eligibility criteria from a total of 417 unique records initially examined. Estimates of effect sizes (r) obtained from these studies were analysed using Comprehensive Meta-Analysis. In these analyses, we compared participants identified as having a past history of suicide attempt(s) to those with no such history. Study quality, mean age of sample and percentage of male participants were examined as potential moderators. Overall, there was no significant effect of suicide group on cortisol. However, significant associations between cortisol and suicide attempts were observed as a function of age. In studies where the mean age of the sample was below 40 years the association was positive (i.e., higher cortisol was associated with suicide attempts; r=.234, p<.001), and where the mean age was 40 or above the association was negative (i.e., lower cortisol was associated with suicide attempts; r=-.129, p<.001). These findings confirm that HPA axis activity, as indicated by age-dependent variations in cortisol levels, is associated with suicidal behavior. The challenge for theory and clinical practice is to explain the complete reversal of the association with age and to identify its clinical implications.

Consequences of Circadian Disruption on Neurologic Health

Circadian rhythms have a major role in physiology and behavior. Circadian disruption has negative consequences for physiologic homeostasis at molecular, cellular, organ-system, and whole-organism levels. The onset of many cerebrovascular insults shows circadian temporal trends. Impaired sleep-wake cycle, the most robust output rhythms of the circadian system, is significantly affected by neurodegenerative disorders, may precede them by decades, and may also affect their progression. Emerging evidence suggests that circadian disruption may be a risk factor for these neurologic disorders. This article discusses the implications of circadian rhythms in brain disorders, with an emphasis on cerebrovascular and neurodegenerative disorders.

Is Dysregulation of the HPA-Axis a Core Pathophysiology Mediating Co-Morbid Depression in Neurodegenerative Diseases?

There is increasing evidence of prodromal manifestation of neuropsychiatric symptoms in a variety of neurodegenerative diseases such as Parkinson's disease (PD) and Huntington's disease (HD). These affective symptoms may be observed many years before the core diagnostic symptoms of the neurological condition. It is becoming more apparent that depression is a significant modifying factor of the trajectory of disease progression and even treatment outcomes. It is therefore crucial that we understand the potential pathophysiologies related to the primary condition, which could contribute to the development of depression. The hypothalamic-pituitary-adrenal (HPA)-axis is a key neuroendocrine signaling system involved in physiological homeostasis and stress response. Disturbances of this system lead to severe hormonal imbalances, and the majority of such patients also present with behavioral deficits and/or mood disorders. Dysregulation of the HPA-axis is also strongly implicated in the pathology of major depressive disorder. Consistent with this, antidepressant drugs, such as the selective serotonin reuptake inhibitors have been shown to alter HPA-axis activity. In this review, we will summarize the current state of knowledge regarding HPA-axis pathology in Alzheimer's, PD and HD, differentiating between prodromal and later stages of disease progression when evidence is available. Both clinical and preclinical evidence will be examined, but we highlight animal model studies as being particularly useful for uncovering novel mechanisms of pathology related to co-morbid mood disorders. Finally, we purpose utilizing the preclinical evidence to better inform prospective, intervention studies.

Diminished brain resilience syndrome: A modern day neurological pathology of increased susceptibility to mild brain trauma, concussion, and downstream neurodegeneration

The number of sports-related concussions has been steadily rising in recent years. Diminished brain resilience syndrome is a term coined by the lead author to describe a particular physiological state of nutrient functional deficiency and disrupted homeostatic mechanisms leading to increased susceptibility to previously considered innocuous concussion. We discuss how modern day environmental toxicant exposure, along with major changes in our food supply and lifestyle practices, profoundly reduce the bioavailability of neuro-critical nutrients such that the normal processes of homeostatic balance and resilience are no longer functional. Their diminished capacity triggers physiological and biochemical 'work around' processes that result in undesirable downstream consequences. Exposure to certain environmental chemicals, particularly glyphosate, the active ingredient in the herbicide, Roundup(®), may disrupt the body's innate switching mechanism, which normally turns off the immune response to brain injury once danger has been removed. Deficiencies in serotonin, due to disruption of the shikimate pathway, may lead to impaired melatonin supply, which reduces the resiliency of the brain through reduced antioxidant capacity and alterations in the cerebrospinal fluid, reducing critical protective buffering mechanisms in impact trauma. Depletion of certain rare minerals, overuse of sunscreen and/or overprotection from sun exposure, as well as overindulgence in heavily processed, nutrient deficient foods, further compromise the brain's resilience. Modifications to lifestyle practices, if widely implemented, could significantly reduce this trend of neurological damage.

Melatonin in Alzheimer's disease

Alzheimer’s disease (AD), an age-related neurodegenerative disorder with progressive cognition deficit, is characterized by extracellular senile plaques (SP) of aggregated β-amyloid (Aβ) and intracellular neurofibrillary tangles, mainly containing the hyperphosphorylated microtubule-associated protein tau. Multiple factors contribute to the etiology of AD in terms of initiation and progression. Melatonin is an endogenously produced hormone in the brain and decreases during aging and in patients with AD. Data from clinical trials indicate that melatonin supplementation improves sleep, ameliorates sundowning and slows down the progression of cognitive impairment in AD patients. Melatonin efficiently protects neuronal cells from Aβ-mediated toxicity via antioxidant and anti-amyloid properties. It not only inhibits Aβ generation, but also arrests the formation of amyloid fibrils by a structure-dependent interaction with Aβ. Our studies have demonstrated that melatonin efficiently attenuates Alzheimer-like tau hyperphosphorylation. Although the exact mechanism is still not fully understood, a direct regulatory influence of melatonin on the activities of protein kinases and protein phosphatases is proposed. Additionally, melatonin also plays a role in protecting the cholinergic system and in anti-inflammation. The aim of this review is to stimulate interest in melatonin as a potentially useful agent in the prevention and treatment of AD.

Reciprocal interactions between sleep, circadian rhythms and Alzheimer's disease: focus on the role of hypocretin and melatonin

AD, sleep and circadian rhythm physiology display an intricate relationship. On the one hand, AD pathology leads to sleep and circadian disturbances, with a clear negative influence on quality of life. On the other hand, there is increasing evidence that both sleep and circadian regulating systems exert an influence on AD pathology. In this review we describe the impairments of both sleep regulating systems and circadian rhythms in AD and their link to clinical symptoms, as this may increase knowledge on appropriate diagnosis and adequate treatment of sleep problems in AD. Furthermore we discuss how sleep regulating systems, and especially neurotransmitters such as melatonin and hypocretin, may affect AD pathophysiology, as this may provide a role for lack of sleep and circadian rhythm deterioration in the onset of AD.

A review: inflammatory process in Alzheimer's disease, role of cytokines

Alzheimer's disease (AD) is the most common neurodegenerative disorder to date. Neuropathological hallmarks are β-amyloid (Aβ) plaques and neurofibrillary tangles, but the inflammatory process has a fundamental role in the pathogenesis of AD. Inflammatory components related to AD neuroinflammation include brain cells such as microglia and astrocytes, the complement system, as well as cytokines and chemokines. Cytokines play a key role in inflammatory and anti-inflammatory processes in AD. An important factor in the onset of inflammatory process is the overexpression of interleukin (IL)-1, which produces many reactions in a vicious circle that cause dysfunction and neuronal death. Other important cytokines in neuroinflammation are IL-6 and tumor necrosis factor (TNF)-α. By contrast, other cytokines such as IL-1 receptor antagonist (IL-1ra), IL-4, IL-10, and transforming growth factor (TGF)-β can suppress both proinflammatory cytokine production and their action, subsequently protecting the brain. It has been observed in epidemiological studies that treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) decreases the risk for developing AD. Unfortunately, clinical trials of NSAIDs in AD patients have not been very fruitful. Proinflammatory responses may be countered through polyphenols. Supplementation of these natural compounds may provide a new therapeutic line of approach to this brain disorder.

Older poor-sleeping women display a smaller evening increase in melatonin secretion and lower values of melatonin and core body temperature than good sleepers

Melatonin concentration and core body temperature (CBT) follow endogenous circadian biological rhythms. In the evening, melatonin level increases and CBT decreases. These changes are involved in the regulation of the sleep-wake cycle. Therefore, the authors hypothesized that age-related changes in these rhythms affect sleep quality in older people. In a cross-sectional study design, 11 older poor-sleeping women (aged 62-72 yrs) and 9 older good-sleeping women (60-82 yrs) were compared with 10 younger good-sleeping women (23-28 yrs). The older groups were matched by age and body mass index. Sleep quality was assessed by the Pittsburgh Sleep Quality Index questionnaire. As an indicator of CBT, oral temperature was measured at 1-h intervals from 17:00 to 24:00 h. At the same time points, saliva samples were collected for determining melatonin levels by enzyme-linked immunosorbent assay (ELISA). The dim light melatonin onset (DLMO), characterizing the onset of melatonin production, was calculated. Evening changes in melatonin and CBT levels were tested by the Friedman test. Group comparisons were performed with independent samples tests. Predictors of sleep-onset latency (SOL) were assessed by regression analysis. Results show that the mean CBT decreased in the evening from 17:00 to 24:00 h in both young women (from 36.57°C to 36.25°C, p < .001) and older women (from 36.58°C to 35.88°C, p < .001), being lowest in the older poor sleepers (p < .05). During the same time period, mean melatonin levels increased in young women (from 16.2 to 54.1 pg/mL, p < .001) and older women (from 10.0 to 23.5 pg/mL, p < .001), being lowest among the older poor sleepers (from 20:00 to 24:00 h, p < .05 vs. young women). Older poor sleepers also showed a smaller increase in melatonin level from 17:00 to 24:00 h than older good sleepers (mean ± SD: 7.0 ± 9.63 pg/mL vs. 15.6 ± 24.1 pg/mL, p = .013). Accordingly, the DLMO occurred at similar times in young (20:10 h) and older (19:57 h) good-sleeping women, but was delayed ∼50 min in older poor-sleeping women (20:47 h). Older poor sleepers showed a shorter phase angle between DLMO and sleep onset, but a longer phase angle between CBT peak and sleep onset than young good sleepers, whereas older good sleepers had intermediate phase angles (insignificant). Regression analysis showed that the DLMO was a significant predictor of SOL in the older women (R(2) = 0.64, p < .001), but not in the younger women. This indicates that melatonin production started later in those older women who needed more time to fall asleep. In conclusion, changes in melatonin level and CBT were intact in older poor sleepers in that evening melatonin increased and CBT decreased. However, poor sleepers showed a weaker evening increase in melatonin level, and their DLMO was delayed compared with good sleepers, suggesting that it is not primarily the absolute level of endogenous melatonin, but rather the timing of the circadian rhythm in evening melatonin secretion that might be related to disturbances in the sleep-wake cycle in older people.

Diurnal variation of cortisol in people with dementia: relationship to cognition and illness burden

Cortisol patterns in nursing home residents with dementia are described and examined in relation to cognition and comorbid illnesses. Saliva was sampled 4 times in a 24-hour period (week 1) and at the same times 1 week later (week 2). In general, cortisol levels decreased from morning to evening, with 50% exhibiting a negative slope. In contrast, 38% of the participants had a relatively flat cortisol diurnal rhythm, and 7% exhibited an afternoon increase. The cortisol pattern was consistent between weeks 1 and 2 for 39% with a negative slope, 13% with a flat profile, and for 2% with an afternoon increase pattern. Cortisol rhythm was not statistically significantly related to cognition or illness burden. While this study contributes to the understanding of differences in the diurnal pattern of cortisol for older adults with dementia, more research is needed to understand the etiology of the differences and the biological mechanisms involved.

Morning Cortisol in Relation to Behavioral Symptoms of Nursing Home Residents With Dementia

Behavioral symptoms of dementia (BSD) are a significant challenge for elders, their caregivers, and clinicians, with a prevalence ranging between 66% and 98%. Although several studies have examined BSD type and frequency, few studies have examined a possible neuroendocrine basis of BSD. The purpose of this study was to examine the association between morning cortisol levels and BSD in nursing home (NH) residents. Method: Using a within-subject longitudinal design, saliva was collected four times daily for 5 days to obtain basal cortisol levels from 30 NH residents, aged 80 to 102. Behavior was observed every 20 min for 12 hr/day for 5 days. Mixed-model analysis was used to test the association between morning cortisol (MC) and BSD. To examine the association between MC and BSD across time, participants were divided into low (LM) and high morning (HM) cortisol groups. Results: A significant inverse association between mean overall BSD and morning cortisol (F = 12.71, p = .000) was found. A significant inverse association between low and high morning cortisol and behavior variability across time (F = 15.36. p = .000) was found. The LM group exhibited significantly more behavioral variability across the day than the HM cortisol group. There was a significant group difference between two co-occurring behaviors, vocalization, and restlessness (F = 19.59, p = .000). Conclusion: Although preliminary, these results suggest an association between morning cortisol and BSD. Low morning cortisol, potentially indicating HPA axis dysregulation, may increase vulnerability to BSD.

Melatonin as a therapeutic tool in ophthalmology: implications for glaucoma and uveitis

Several lines of evidence support the view that increased free radical generation and altered nitric oxide (NO) metabolism play a role in the pathogenesis of highly prevalent ocular diseases, such as glaucoma and uveitis. Data are discussed indicating that melatonin, being an efficient antioxidant that displays antinitridergic properties, has a promising role in the treatment of these ocular dysfunctions. Melatonin synthesis occurs in the eye of most species, and melatonin receptors are localized in different ocular structures. In view of the fact that melatonin lacks significant adverse collateral effects even at high doses, the application of melatonin could potentially protect ocular tissues by effectively scavenging free radicals and excessive amounts of NO generated in the glaucomatous or uveitic eye.

Reduced limbic and hypothalamic volumes correlate with bone density in early Alzheimer's disease

Accelerated bone loss is associated with Alzheimer's disease (AD). Although the central nervous system plays a direct role in regulating bone mass, primarily through the actions of the hypothalamus, there is little work investigating the possible role of neurodegeneration in bone loss. In this cross-sectional study, we examined the association between bone mineral density (BMD) and neuroimaging markers of neurodegeneration (i.e., global and regional measures of brain volume) in early AD and non-demented aging. Fifty-five non-demented and 63 early AD participants underwent standard neurological and neuropsychological assessment, structural MRI scanning, and dual energy x-ray absorptiometry. In early AD, voxel-based morphometry analyses demonstrated that low BMD was associated with low volume in limbic grey matter (GM) including the hypothalamus, cingulate, and parahippocampal gyri and in the left superior temporal gyrus and left inferior parietal cortex. No relationship between BMD and regional GM volume was found in non-demented controls. The hypothesis-driven region of interest analysis further isolating the hypothalamus demonstrated a positive relationship between BMD and hypothalamic volume after controlling for age and gender in the early AD group but not in non-demented controls. These results demonstrate that lower BMD is associated with lower hypothalamic volume in early AD, suggesting that central mechanisms of bone remodeling may be disrupted by neurodegeneration.

The role of stress factors during aging of the immune system

This manuscript reviews current evidence suggesting that aging of the immune system (immunosenescence) may be closely related to chronic stress and stress factors. Healthy aging has been associated with emotional distress in parallel to increased cortisol to dehydroepiandrosterone (DHEA) ratio. The impaired DHEA secretion together with the increase of cortisol results in an enhanced exposure of lymphoid cells to deleterious glucocorticoid actions. The lack of appropriated growth hormone signaling during immunosenescence is also discussed. It follows that altered neuroendocrine functions could be underlying several immunosenescence features. Indeed, changes in both innate and adaptive immune responses during aging are also similarly reported during chronic glucocorticoid exposure. In addition, chronically stressed elderly subjects may be particularly at risk of stress-related pathology because of further alterations in both neuroendocrine and immune systems. The accelerated senescent features induced by chronic stress include higher oxidative stress, reduced telomere length, chronic glucocorticoid exposure, thymic involution, changes in cellular trafficking, reduced cell-mediated immunity, steroid resistance, and chronic low-grade inflammation. These senescent features are related to increased morbidity and mortality among chronically stressed elderly people. Overall, these data suggest that chronic stress leads to premature aging of key allostatic systems involved in the adaptation of the organisms to environmental changes. Stress management and psychosocial support may thus promote a better quality of life for elderly people and at the same time reduce hospitalization costs.

Daytime levels of melatonin in patients with age-related macular degeneration

PURPOSE

Melatonin (N-acetyl-5-methoxytryptamine) (MT) is a hormone that acts as an antioxidant. It is produced by the pineal gland and within the retina; its release is blocked by light entering the eye. We examined whether MT daytime levels differ between pseudophakic patients with age-related macular degeneration (ARMD) and pseudophakic subjects without any ocular pathology of the same age.

METHODS

A prospective, cross-sectional, observational study was performed. Pseudophakic patients of the same age group were included. Patients underwent complete ophthalmic examinations and blood sampling between 08:00 and 10:00 hr. MT daytime value in the serum was the main outcome measure.

RESULTS

Sixty-nine pseudophakic patients were included. Fifty patients with exudative and non-exudative ARMD were in the study group while 19 patients were controls. Patients with ARMD had significantly higher daytime levels of MT (P = 0.003). There were significant differences in MT daytime levels between the exudative and non-exudative forms (P = 0.009). MT values also correlated with the best-corrected visual acuity (r = -0.285, P = 0.019).

CONCLUSION

These data indicate that pseudophakic patients with ARMD produce more MT during the day compared to pseudophakic subjects without ARMD. This may be caused by the reduced visual acuity in patients with ARMD, whereby less light reaches the photoreceptors, allowing MT secretion to continue during the day. Because MT also acts as an antioxidant and daytime levels are higher in patients with ARMD, these results might be interpreted as a rescue factor.

Neurobiological and neuropsychiatric effects of dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS)

DHEA and DHEAS are steroids synthesized in human adrenals, but their function is unclear. In addition to adrenal synthesis, evidence also indicates that DHEA and DHEAS are synthesized in the brain, further suggesting a role of these hormones in brain function and development. Despite intensifying research into the biology of DHEA and DHEAS, many questions concerning their mechanisms of action and their potential involvement in neuropsychiatric illnesses remain unanswered. We review and distill the preclinical and clinical data on DHEA and DHEAS, focusing on (i) biological actions and putative mechanisms of action, (ii) differences in endogenous circulating concentrations in normal subjects and patients with neuropsychiatric diseases, and (iii) the therapeutic potential of DHEA in treating these conditions. Biological actions of DHEA and DHEAS include neuroprotection, neurite growth, and antagonistic effects on oxidants and glucocorticoids. Accumulating data suggest abnormal DHEA and/or DHEAS concentrations in several neuropsychiatric conditions. The evidence that DHEA and DHEAS may be fruitful targets for pharmacotherapy in some conditions is reviewed.

The neuroprotective role of melatonin against amyloid beta peptide injected mice

Widespread cerebral deposition of a 40-42 amino acid peptide called amyloid beta peptide (A beta) in the form of amyloid fibrils is one of the most prominent neuropathologic features of Alzheimer's disease (AD). The clinical study provides evidence that accumulation of protofibrils due to the Arctic mutation (E22G) causes early AD onset. Melatonin showed beneficial effects in an AD mouse model. Mice were divided into four different groups (n=8 per group): (i) control group, (ii) scrambled A beta-injected group, (iii) A beta protofibril-injected group and (iv) melatonin-treated group. A single dose of (5 microg) A beta protofibril was administered to the A beta protofibril-injected and melatonin-treated groups via intracerebroventricular injections. The results demonstrate that melatonin treatment significantly reduces A beta protofibril-induced reactive oxygen species (ROS) production, intracellular calcium levels and acetylcholinesterase activity in the neocortex and hippocampus regions. Based on these findings it is suggested that melatonin therapy might be a useful treatment for AD patients.

Effect of age and caloric restriction on circadian adrenal steroid rhythms in rhesus macaques

Dietary caloric restriction (CR) slows aging, extends lifespan, and reduces the occurrence of age-related diseases in short-lived species. However, it is unclear whether CR can exert similar beneficial effects in long-lived species, like primates. Our objective was to determine if CR could attenuate purported age-related changes in the 24-h release of adrenal steroids. To this end, we examined 24-h plasma profiles of cortisol, and dehydroepiandrosterone sulfate (DHEAS) in young and old, male and female rhesus macaques (Macaca mulatta) subjected to either ad libitum (AL)-feeding or CR (70% of AL) for 2-4 years. Hormone profiles from young monkeys showed pronounced 24-h rhythms. Cortisol concentrations were higher in old males but not females, whereas DHEAS rhythms were dampened with age in both sexes. The cortisol rhythms of old CR males resembled those of young control males. However, CR failed to prevent age-related declines in DHEAS and further dampened DHEAS rhythms in both sexes. Apart from the partial attenuation of the age-related cortisol elevation in the old males, 24-h adrenal steroid rhythms did not benefit from late-onset CR.

Atypical evening cortisol profile induces visual recognition memory deficit in healthy human subjects

BACKGROUND

Diurnal rhythm-mediated endogenous cortisol levels in humans are characterised by a peak in secretion after awakening that declines throughout the day to an evening trough. However, a significant proportion of the population exhibits an atypical cycle of diurnal cortisol due to shift work, jet-lag, aging, and mental illness.

RESULTS

The present study has demonstrated a correlation between elevation of cortisol in the evening and deterioration of visual object recognition memory. However, high evening cortisol levels have no effect on spatial memory.

CONCLUSION

This study suggests that atypical evening salivary cortisol levels have an important role in the early deterioration of recognition memory. The loss of recognition memory, which is vital for everyday life, is a major symptom of the amnesic syndrome and early stages of Alzheimer's disease. Therefore, this study will promote a potential physiologic marker of early deterioration of recognition memory and a possible diagnostic strategy for Alzheimer's disease.

Total lymphocyte count and in-hospital mortality in older persons with multimorbidity

BACKGROUND AND AIMS

Low total lymphocyte count (TLC) has been found to be a poor prognostic factor in adults affected by heart diseases, malignancy, and renal failure. The aims of this study were to verify if a low TLC was associated with in-hospital mortality in older persons and to evaluate whether this association was independent of the presence of multiple co-existing diseases (multimorbidity).

METHODS

The authors carried out a cross-section analysis of data of 65+ years old patients (n=596) admitted to a Geriatric Unit in Northern Italy. TLC, total white blood cell count (WBC) and serum albumin were assayed the day after admission. The presence and severity of diseases were evaluated with the Geriatric Index of Comorbidity (GIC). Other covariates included age, gender, cigarette smoking, cognition (Mini-Mental State Examination) and function (Activities of Daily Living). Logistic regression models were created to study factors affecting in-hospital death.

RESULTS

TLC was inversely correlated with both age and multimorbidity. Patients in the lowest tertile of TLC had the highest association with death during hospitalization (OR 6.1, 95% CI 1.1-33.6) independently of multimorbidity and all the other covariates. Stratifying the sample by degree of multimorbidity, this association was clearest in patients with the least severe multimorbidity (GIC <or=3).

CONCLUSIONS

Although TLC and multimorbidity were correlated, they emerged as independent predictors of in-hospital death. Further investigations into possible biological mechanisms underlying the association of lymphocytes and adverse outcomes in old persons are needed.

Role of neuroendocrine pathways in cognitive decline during aging

The pineal and pituitary-adrenocortical secretions play an important role in adaptive responses of the organism acting as coordinating signals for both several biological rhythms and multiple neuroendocrine and metabolic functions. The more relevant neuroendocrine changes occurring with ageing affect the secretion of melatonin and of corticosteroids. These changes may be clearly appreciated by the study of their circadian rhythmicity. The circadian profile of plasma melatonin was clearly flattened in elderly subjects and even more in old individuals with dementia. Indeed, the impairment of melatonin signal occurring in aging was related either to age itself or to the cognitive performances of subjects. The biosynthetic dissociation between glucocorticoids and androgen secretion is responsible for the selective impairment of androgens, such as DHEA and DHEA-S, by comparison to cortisol. Due to the opposite effects of the two kinds of corticosteroids either in the periphery and in the CNS, the imbalance between glucocorticoids and androgens, well demonstrated by the evaluation of the cortisol/DHEA-S molar ratio, may be responsible for the occurrence in the CNS of a more neurotoxic steroidal milieu, already present in clinically healthy elderly subjects and especially in patients with dementia. The effects of that steroidal milieu are more prominent at the level of the hippocampal-limbic structure, involved both in the modulation of endocrine structures, such as the HPA axis, and in the control of cognitive, behavioral and affective functions.