Menstrual cycle and reproductive aging alters immune reactivity, NGF expression, antioxidant enzyme activities, and intracellular signaling pathways in the peripheral blood mononuclear cells of healthy women

Trajectories of peripheral white blood cells count around the menopause: a prospective cohort study

BACKGROUND

Menopause significantly impacts the immune system. Postmenopausal women are more susceptible to infection. Nonetheless, the pattern of change in peripheral white blood cell counts around the menopause remains poorly understood.

METHODS

We conducted a prospective longitudinal cohort study with repeated measurements using Kailuan cohort study of 3632 Chinese women who participated in the first checkup (2006-2007) and reached their final menstrual period (FMP) by the end of the seventh checkup (2018-2020). Peripheral WBC count indicators included total white blood cells (TWBC), neutrophils (NEUT), lymphocytes (LYM), and monocytes (MON). Multivariable mixed effects regressions fitted piece-wise linear models to repeated measures of WBC count indicators as a function of time before or after the final menstrual period (FMP). Interaction and subgroup analysis were used to explore the effects of age and body mass index (BMI) on changes in WBC indicators around FMP.

RESULTS

WBC count indicators decreased before the FMP, and the reduction in TWBC, NEUT, and MON continued for 2 years following the FMP. LYM and NEUT declined during < -1 years and - 4 ∼ + 2 years relative to FMP, respectively. A reduction in MON was observed pre-FMP, extending continuously through the two-year period post-FMP. TWBC declined from - 3 to + 2 years relative to FMP, but both MON and TWBC increased during > + 2 years. The baseline age had an interaction effect on changes in WBC indicators during specific menopausal stages, except for TWBC. Individuals in different age subgroups showed distinct trajectories for NEUT, LYM and MON around the FMP. High baseline BMI had a synergistic effect on changes in specific menopause segments for TWBC, LYM, and MON. The impact of menopause on TWBC and LYM was postponed or counterbalanced in high BMI individuals. Individuals in three BMI subgroups experienced similar MON changes around FMP, and there were slight variations during < -4 years.

CONCLUSIONS

Menopause was associated with count changes of peripheral WBC. The trajectories of various WBC types differ around menopause. Age and BMI affected WBC trajectory around menopause. The menopause period may represent a window of opportunity to promote immune health in middle-aged women.

Estrogen-immuno-neuromodulation disorders in menopausal depression

A significant decrease in estrogen levels puts menopausal women at high risk for major depression, which remains difficult to cure despite its relatively clear etiology. With the discovery of abnormally elevated inflammation in menopausal depressed women, immune imbalance has become a novel focus in the study of menopausal depression. In this paper, we examined the characteristics and possible mechanisms of immune imbalance caused by decreased estrogen levels during menopause and found that estrogen deficiency disrupted immune homeostasis, especially the levels of inflammatory cytokines through the ERα/ERβ/GPER-associated NLRP3/NF-κB signaling pathways. We also analyzed the destruction of the blood-brain barrier, dysfunction of neurotransmitters, blockade of BDNF synthesis, and attenuation of neuroplasticity caused by inflammatory cytokine activity, and investigated estrogen-immuno-neuromodulation disorders in menopausal depression. Current research suggests that drugs targeting inflammatory cytokines and NLRP3/NF-κB signaling molecules are promising for restoring homeostasis of the estrogen-immuno-neuromodulation system and may play a positive role in the intervention and treatment of menopausal depression.

Alterations in Immune Responses Are Associated with Dysfunctional Intracellular Signaling in Peripheral Blood Mononuclear Cells of Men and Women with Mild Cognitive Impairment and Alzheimer's disease

Deficits in the neuroendocrine-immune network in the periphery associated with the onset and progression of mild cognitive impairment (MCI) and Alzheimer's disease (AD) have not been extensively studied. The present study correlatively examines the association between cell-mediated immune responses, stress hormones, amyloid precursor protein (APP) expression, peripheral blood mononuclear cells (PBMC), and intracellular signaling molecules in the pathophysiology of MCI and AD compared to adults. Serum APP, lymphocyte proliferation, total cholinesterase (TChE), butyrylcholinesterase (BChE) activities, cytokines (IL-2, IFN-γ, IL-6, and TNF-α), and intracellular signaling molecules (p-ERK, p-CREB, and p-Akt) were measured in the PBMCs of adult, old, MCI, and AD men and women initially and after 3 years in the same population. An age- and disease-associated decline in mini-mental state examination (MMSE) scores and lymphocyte proliferation of MCI and AD men and women were observed. An age- and disease-related increase in serum APP, cortisol levels, and TChE activity were observed in men and women. Enhanced production of Th1 cytokine, IL-2, pro-inflammatory cytokines, and suppressed intracellular transcription factors may promote the inflammatory environment in MCI and AD patients. The expression of CREB and Akt was lower in MCI and AD men, while the expression of p-ERK was higher, and p-CREB was lower in MCI and AD women after 3 years. These results suggest that changes in specific intracellular signaling pathways may influence alterations in cell-mediated immunity to promote disease progression in MCI and AD patients.

Antioxidant enzymes and Nrf2/Keap1 in human skeletal muscle: Influence of age, sex, adiposity and aerobic fitness

Ageing, a sedentary lifestyle, and obesity are associated with increased oxidative stress, while regular exercise is associated with an increased antioxidant capacity in trained skeletal muscles. Whether a higher aerobic fitness is associated with increased expression of antioxidant enzymes and their regulatory factors in skeletal muscle remains unknown. Although oestrogens could promote a higher antioxidant capacity in females, it remains unknown whether a sex dimorphism exists in humans regarding the antioxidant capacity of skeletal muscle. Thus, the aim was to determine the protein expression levels of the antioxidant enzymes SOD1, SOD2, catalase and glutathione reductase (GR) and their regulatory factors Nrf2 and Keap1 in 189 volunteers (120 males and 69 females) to establish whether sex differences exist and how age, VO2max and adiposity influence these. For this purpose, vastus lateralis muscle biopsies were obtained in all participants under resting and unstressed conditions. No significant sex differences in Nrf2, Keap1, SOD1, SOD2, catalase and GR protein expression levels were observed after accounting for VO2max, age and adiposity differences. Multiple regression analysis indicates that the VO2max in mL.kg LLM-1.min-1can be predicted from the levels of SOD2, Total Nrf2 and Keap1 (R = 0.58, P < 0.001), with SOD2 being the main predictor explaining 28 % of variance in VO2max, while Nrf2 and Keap1 explained each around 3 % of the variance. SOD1 protein expression increased with ageing in the whole group after accounting for differences in VO2max and body fat percentage. Overweight and obesity were associated with increased pSer40-Nrf2, pSer40-Nrf2/Total Nrf2 ratio and SOD1 protein expression levels after accounting for differences in age and VO2max. Overall, at the population level, higher aerobic fitness is associated with increased basal expression of muscle antioxidant enzymes, which may explain some of the benefits of regular exercise.

Oxidative stress as a key modulator of cell fate decision in osteoarthritis and osteoporosis: a narrative review

During aging and after traumatic injuries, cartilage and bone cells are exposed to various pathophysiologic mediators, including reactive oxygen species (ROS), damage-associated molecular patterns, and proinflammatory cytokines. This detrimental environment triggers cellular stress and subsequent dysfunction, which not only contributes to the development of associated diseases, that is, osteoporosis and osteoarthritis, but also impairs regenerative processes. To counter ROS-mediated stress and reduce the overall tissue damage, cells possess diverse defense mechanisms. However, cellular antioxidative capacities are limited and thus ROS accumulation can lead to aberrant cell fate decisions, which have adverse effects on cartilage and bone homeostasis. In this narrative review, we address oxidative stress as a major driver of pathophysiologic processes in cartilage and bone, including senescence, misdirected differentiation, cell death, mitochondrial dysfunction, and impaired mitophagy by illustrating the consequences on tissue homeostasis and regeneration. Moreover, we elaborate cellular defense mechanisms, with a particular focus on oxidative stress response and mitophagy, and briefly discuss respective therapeutic strategies to improve cell and tissue protection.

The effects of menstrual cycle phases on immune function and inflammation at rest and after acute exercise: A systematic review and meta-analysis

The immune system plays an important role in mediating exercise responses and adaptations. However, whether fluctuating hormone concentrations across the menstrual cycle may impact these processes remains unknown. The aim of this systematic review with meta-analysis was to compare baseline concentrations as well as exercise-induced changes in immune and inflammatory parameters between menstrual cycle phases. A systematic literature search was conducted according to the PRISMA guidelines using Pubmed/MEDLINE, ISI Web of Science, and SPORTDiscus. Of the 159 studies included in the qualitative synthesis, 110 studies were used for meta-analysis. Due to the designs of the included studies, only the follicular and luteal phase could be compared. The estimated standardized mean differences based on the random-effects model revealed higher numbers of leukocytes (-0.48 [-0.73; -0.23], p < 0.001), monocytes (-0.73 [-1.37; -0.10], p = 0.023), granulocytes (-0.85 [-0.1.48; -0.21], p = 0.009), neutrophils (-0.32 [-0.52; -0.12], p = 0.001), and leptin concentrations (-0.37 [-0.5; -0.23], p = 0.003) in the luteal compared to the follicular phase at rest. Other parameters (adaptive immune cells, cytokines, chemokines, and cell adhesion molecules) showed no systematic baseline differences. Seventeen studies investigated the exercise-induced response of these parameters, providing some indications for a higher pro-inflammatory response in the luteal phase. In conclusion, parameters of innate immunity showed cycle-dependent regulation at rest, while little is known on the exercise responses. Due to a large heterogeneity and a lack of cycle phase standardization among the included studies, future research should focus on comparing at least three distinct hormonal profiles to derive more specific recommendations for exercise prescription.

Preparation of pumpkin oil-based nanoemulsion as a potential estrogen replacement therapy to alleviate neural-immune interactions in an experimental postmenopausal model

As estrogen production decreases during menopause; the brain's metabolism tends to stall and become less effective. Estrogen most likely protects against neurodegeneration. Consequently, a comprehensive study of the benefits of hormone replacement therapy as a neuroprotective effect is urgently required. This study was designed to fabricate pumpkin seed oil nanoparticles (PSO) in nanoemulsion form (PSO-NE) and investigate their potential role in attenuating the neural-immune interactions in an experimental postmenopausal model.Sixty female white albino rats were divided into six groups: control, sham, ovariectomized (OVX), and three OVX groups treated with 17β-estradiol, PSO, and PSO-NE respectively. Transmission Electron Microscopy (TEM), and particle size analyzer were performed for nanoemulsion evaluation. Serum levels of estrogen, brain amyloid precursor protein (APP), serum levels of nuclear factor kappa B (NF-κβ), interleukin 6 (IL-6), transthyretin (TTR), and synaptophysin (SYP) were evaluated. The expression of estrogen receptors (ER-α, β) in the brain tissue was estimated. The findings revealed that the approached PSO-NE system was able to reduce the interfacial tension, enhance the dispersion entropy, lower the system free energy to an extremely small value, and augment the interfacial area. PSO-NE, showed a significant increase in the levels of estrogen, brain APP, SYP, and TTR accompanied with a significant increased in the expression of brain ER-α, β compared to the OVX group. In conclusion, the phytoestrogen content of PSO exhibited a significant prophylactic effect on neuro-inflammatory interactions, ameliorating both estrogen levels and the inflammatory cascades.

17β-Estradiol Concentration and Direct β2-Adrenoceptor Inhibition Determine Estrogen-Mediated Reversal of Adrenergic Immunosuppression

Background:

Sympathetic innervation of lymphoid organs, and the presence of 17β-estradiol (estrogen or E2) and adrenergic receptors (ARs) on lymphocytes, suggests that sympathetic stimulation and hormonal activation may influence immune functions.

Purpose:

Modeling and simulating these pathways may help to understand the dynamics of neuroendocrine-immune modulation at the cellular and molecular levels.

Methods:

Dose- and receptor-dependent effects of E2 and AR subtype-specific agonists were established in vitro on lymphocytes from young male Sprague-Dawley rats and were modeled in silico using the MATLAB Simbiology toolbox. Kinetic principles were assigned to define receptor–ligand dynamics, and concentration/time plots were obtained using Ode15s solvers at different time intervals for key regulatory molecules. Comparisons were drawn between in silico and in vitro data for validating the constructed model with sensitivity analysis of key regulatory molecules to assess their individual impacts on the dynamics of the system. Finally, docking studies were conducted with key ligands E2 and norepinephrine (NE) to understand the mechanistic principles underlying their interactions.

Results:

Adrenergic activation triggered proapoptotic signals, while E2 enhanced survival signals, showing opposing effects as observed in vitro. Treatment of lymphocytes with E2 shows a 10-fold increase in survival signals in a dose-dependent manner. Cyclic adenosine monophosphate (cAMP) activation is crucial for the activation of survival signals through extracellular signal-regulated kinase (p-ERK) and cAMP responsive element binding (p-CREB) protein. Docking studies showed the direct inhibition of ERK by NE and β2-AR by E2 explaining how estrogen signaling overrides NE-mediated immunosuppression in vitro.

Conclusion:

The cross-talk between E2 and adrenergic signaling pathways determines lymphocyte functions in a receptor subtype and coactivation-dependent manner in health and disease.

Neuroimmunomodulation by estrogen in health and disease

Systemic homeostasis is maintained by the robust bidirectional regulation of the neuroendocrine-immune network by the active involvement of neural, endocrine and immune mediators. Throughout female reproductive life, gonadal hormones undergo cyclic variations and mediate concomitant modulations of the neuroendocrine-immune network. Dysregulation of the neuroendocrine-immune network occurs during aging as a cumulative effect of declining neural, endocrine and immune functions and loss of compensatory mechanisms including antioxidant enzymes, growth factors and co-factors. This leads to disruption of homeostasis and sets the stage for the development of female-specific age-associated diseases such as autoimmunity, osteoporosis, cardiovascular diseases and hormone-dependent cancers. Ovarian hormones especially estrogen, play a key role in the maintenance of health and homeostasis by modulating the nervous, endocrine and immune functions and thereby altering neuroendocrine-immune homeostasis. Immunologically estrogen's role in the modulation of Th1/Th2 immune functions and contributing to pro-inflammatory conditions and autoimmunity has been widely studied. Centrally, hypothalamic and pituitary hormones influence gonadal hormone secretion in murine models during onset of estrous cycles and are implicated in reproductive aging-associated acyclicity. Loss of estrogen affects neuronal plasticity and the ensuing decline in cognitive functions during reproductive aging in females implicates estrogen in the incidence and progression of neurodegenerative diseases. Peripherally, sympathetic noradrenergic (NA) innervations of lymphoid organs and the presence of both adrenergic (AR) and estrogen receptors (ER) on lymphocytes poise estrogen as a potent neuroimmunomodulator during health and disease. Cyclic variations in estrogen levels throughout reproductive life, perimenopausal surge in estrogen levels followed by its precipitous decline, concomitant with decline in central hypothalamic catecholaminergic activity, peripheral sympathetic NA innervation and associated immunosuppression present an interesting study to explore female-specific age-associated diseases in a new light.

Sex-Based Differences in the Cytokine Production and Intracellular Signaling Pathways in Patients With Rheumatoid Arthritis

Objectives

This study aims to investigate lymphoproliferation, cytokine production, and intracellular signaling molecules in peripheral blood mononuclear cells (PBMCs) isolated from healthy individuals and rheumatoid arthritis (RA) patients to understand the extent of the involvement of these pathways in the pathogenesis of RA.

Patients and methods

The study included 65 participants (29 males, 36 females; mean age 51.8±10.3 years; range, 37 to 71 years) who were categorized into four groups as healthy males (n=22, mean age 49.8±10.6 years; range, 39 to 65 years), male RA patients (n=7, mean age 51.8±13.9 years; range, 37 to 68 years), healthy females (n=20, mean age 53.7±8.8 years; range, 42 to 67 years), and female RA patients (n=16, mean age 52.9±10.4 years; range, 40 to 71 years). PBMCs were collected from the participants and analyzed for Concanavalin A (Con A)-induced lymphoproliferation using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, cytokine production, and phospho-signal transducer and activator of transcription 3 (p-STAT-3), phospho-extracellular-signal-regulated kinase (p-ERK), phospho-cAMP response element binding (p-CREB), and phospho-protein kinase B expressions using enzyme-linked immunosorbent assay. Short form of the Arthritis Impact Measurement Scales 2 and multidimensional health assessment questionnaire were used to measure the level of disability and the quality of life.

Results

In RA patients, production of Con A-induced interleukin (IL)-2 and IL-17 was higher in both sexes while interferon-gamma levels decreased in RA females alone. Expression of p-STAT-3 in PBMCs increased in RA males while it was unaltered in RA females. p-ERK expression was not altered while p-CREB expression was enhanced in RA males and females. Protein-protein interaction analyses demonstrated that these and other key signaling molecules were dysregulated in RA patients.

Conclusion

Our results suggest that sex-based differences in RA pathogenesis result from differential alterations in signaling pathways to influence the inflammatory process.

Virgin coconut oil supplementation in diet modulates immunity mediated through survival signaling pathways in rats

Background Virgin coconut oil (VCO), a cold processed form of coconut oil, is traditionally consumed in Asian countries owing to its nutritional and medicinal properties. The aim of this study was to investigate whether the health benefits of VCO involve alterations in immune responses that are regulated by intracellular signaling molecules in the spleens of rats. Methods Young male Wistar rats were fed with three doses of VCO in diet for 30 days. At the end of the treatment period, spleens were isolated and in vitro effects on immune responses (Concanavalin A [Con A]-induced lymphoproliferation and cytokine production), and direct effects of VCO treatment on intracellular signaling molecules and antioxidant status were examined. Serum was collected to measure glucose, lipid levels, and leptin. Results VCO supplementation in diet enhanced Con A-induced splenocyte proliferation and Th1 cytokine production while it suppressed the proinflammatory cytokine production. VCO increased the expression of mechanistic target of rapamycin (p-mTOR), sirtuin1 (SIRT1), liver kinase B1 (p-LKB1) p-ERK, and p-CREB in spleen. Similarly, VCO increased the activities of antioxidant enzymes while it suppressed lipid peroxidation in the spleen. VCO diet had hypolipidemic effects on the rats: an increase in high density lipoprotein cholesterol (HDL-C) levels while lowering triacylglycerol (TAG) levels. Conclusion The health benefits of VCO may be mediated through enhanced Th1 immunity through the upregulation of survival signaling pathways and inhibition of free radical generation in the spleen besides its capacity to induce hypolipidemia.

Gender- and age-dependencies of oxidative stress, as detected based on the steady state concentrations of different biomarkers in the MARK-AGE study

Recently, Weber et al. published a thorough investigation of the age-dependency of oxidative stress (OS) determined by the steady state concentrations of different compounds - oxidation products and antioxidants - that are in common use as biomarkers of OS in 2207 healthy individuals of the cross-sectional MARK-AGE Project. The correlations among biomarkers were significant but weak. These findings may indicate different manifestations of OS and must further be evaluated. Here, we report a refined analysis of OS based on the above-mentioned original data. We show that malondialdehyde (MDA) appears to be sensitive to both gender and age. It is significantly lower and shows a greater age-dependence in women than in men. The age-dependency of MDA in women arises in a stepwise fashion. The age-dependent slope of the steady state concentration is maximal at the age between 50 and 55 years, indicating that it may be attributed to the change of metabolism in the post-menopause. Interestingly, total glutathione (GSH) decreased with age simultaneously with the increase in MDA.

Different biomarkers yield different gender- and age-dependencies. Unlike the concentration of MDA, the concentrations of the other two oxidation products, i.e. protein carbonyls and 3-nitrotyrosine were similar in men and women and appeared to be independent of age in the healthy study population. The analyzed antioxidants exhibited different gender- and age-dependencies. In conclusion, it appears that all the biomarkers assessed here reflect different types of OS and that MDA and GSH reflect the same type of OS.

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Analysis of 10 biomarkers in 2207 healthy men and women of the MARK-AGE Project.

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Different oxidative stress biomarkers yield different gender- and age-dependencies.

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Different types of oxidative stress seem to exist.

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Malondialdehyde and glutathione seem to be of the same type of oxidative stress.

Progesterone-Related Immune Modulation of Pregnancy and Labor

Pregnancy involves a complex interplay between maternal neuroendocrine and immunological systems in order to establish and sustain a growing fetus. It is thought that the uterus at pregnancy transitions from quiescent to laboring state in response to interactions between maternal and fetal systems at least partly via altered neuroendocrine signaling. Progesterone (P4) is a vital hormone in maternal reproductive tissues and immune cells during pregnancy. As such, P4 is widely used in clinical interventions to improve the chance of embryo implantation, as well as reduce the risk of miscarriage and premature labor. Here we review research to date that focus on the pathways through which P4 mediates its actions on both the maternal reproductive and immune system. We will dissect the role of P4 as a modulator of inflammation, both systemic and intrinsic to the uterus, during human pregnancy and labor.

Progesterone Modulation of Pregnancy-Related Immune Responses

Progesterone (P4) is an important steroid hormone for the establishment and maintenance of pregnancy and its functional withdrawal in reproductive tissue is linked with the onset of parturition. However, the effects of P4 on adaptive immune responses are poorly understood. In this study, we took a novel approach by comparing the effects of P4 supplementation longitudinally, with treatment using a P4 antagonist mifepristone (RU486) in mid-trimester pregnancies. Thus, we were able to demonstrate the immune-modulatory functions of P4. We show that, in pregnancy, the immune system is increasingly activated (CD38, CCR6) with greater antigen-specific cytotoxic T cell responses (granzyme B). Simultaneously, pregnancy promotes a tolerant immune environment (IL-10 and regulatory-T cells) that gradually reverses prior to the onset of labor. P4 suppresses and RU486 enhances antigen-specific CD4 and CD8 T cell inflammatory cytokine (IFN-γ) and cytotoxic molecule release (granzyme B). P4 and RU486 effectively modulate immune cell-mediated interactions, by regulating differentiated memory T cell subset sensitivity to antigen stimulation. Our results indicate that P4 and RU486, as immune modulators, share a reciprocal relationship. These data unveil key contributions of P4 to the modulation of the maternal immune system and suggests targets for future modulation of maternal immune function during pregnancy.

Maternal obesity during lactation may protect offspring from high fat diet-induced metabolic dysfunction

Background/Objectives

The current obesity epidemic has spurred exploration of the developmental origin of adult heath and disease. A mother’s dietary choices and health can affect both the early wellbeing and lifelong disease-risk of the offspring.

Subjects/Methods

To determine if changes in the mother’s diet and adiposity have long-term effects on the baby’s metabolism, independently from a prenatal insult, we utilized a mouse model of diet-induced-obesity and cross-fostering. All pups were born to lean dams fed a low fat diet but were fostered onto lean or obese dams fed a high fat diet. This study design allowed us to discern the effects of a poor diet from those of mother’s adiposity and metabolism. The weaned offspring were placed on a high fat diet to test their metabolic function.

Results

In this feeding challenge, all male (but not female) offspring developed metabolic dysfunction. We saw increased weight gain in the pups nursed on an obesity-resistant dam fed a high fat diet, and increased pathogenesis including liver steatosis and adipose tissue inflammation, when compared to pups nursed on either obesity-prone dams on a high fat diet or lean dams on a low fat diet.

Conclusion

Exposure to maternal over-nutrition, through the milk, is sufficient to shape offspring health outcomes in a sex- and organ-specific manner, and milk from a mother who is obesity-prone may partially protect the offspring from the insult of a poor diet.

Estrogen-induced neuroimmunomodulation as facilitator of and barrier to reproductive aging in brain and lymphoid organs

Reproductive aging in females is marked by alterations in gonadal hormones, estrogen and progesterone, that facilitate cessation of reproductive cycles and onset of female-specific diseases such as autoimmune and neurodegenerative diseases, hormone-dependent cancers, and osteoporosis. Bidirectional communication between the three homeostatic systems, nervous system, endocrine system, and immune system, is essential for the maintenance of health and any dysfunction in the cross-talk promotes the development of diseases and cancer. The pleiotropic effects of estrogen on neural-immune interactions may promote either neuroprotection or inflammatory conditions depending on the site of action, dose and duration of treatment, type of estrogen receptors and its influence on intracellular signaling pathways, etc. Our studies involving treatment of early middle-aged female rats with low and high doses of estrogen and examining the brain areas, thymus, spleen, and lymph nodes revealed that estrogen-induced changes in neural-immune interactions are markedly affected in thymus followed by spleen and lymph nodes while it confers neuroprotection in the brain areas. These alterations are determined by antioxidant enzyme status, growth factors, intracellular signaling pathways involved in cell survival and inflammation, and metabolic enzymes and thus, may regulate the various stages in female reproductive aging. It is imperative that detailed longitudinal studies are carried out to understand the mechanisms of neuroendocrine-immune interactions in reproductive aging to facilitate healthy aging and for the development of better treatment strategies for female-specific diseases.

Biochemistry of the menopause

The life of a human female is characterized from teenage years by monthly menstruation which ceases (the menopause) typically between the age of 40 and 60 years. The potential for reproduction declines and ceases as the ovaries become depleted of follicles. A transition period in mid-life, for 2 to 10 years, when menstruation is less regular is called the perimenopause. The menopause is associated with a significant decline in plasma concentrations of sex hormones, an increase in the concentrations of the gonadotrophins and changes in other hormones such as the inhibins. These changes are superimposed with effects of aging, social and metabolic factors, daily activity and well-being. Although the menopause is entirely natural, in some cases ovarian failure can occur earlier than usual; this is pathological and warrants careful biochemical investigations to distinguish it from conditions causing infertility. Elderly females are affected by a range of clinical disorders including endocrine, cardiovascular, skeletal, urogenital tract and immunological systems, body mass, vasomotor tone, mood and sleep pattern. Reference intervals for many diagnostic biochemical tests for the menopause need to be used when interpreting results in clinical investigations for patient management. The standardization and harmonization of assays are being addressed. Many women now choose to develop their career before bearing children, and the health service has had to change services around this. This review does not cover screening for and tests during pregnancy. The review is timely since the population is aging and there will be more demand on healthcare services.

Changes in immune cell distribution and their cytokine/chemokine production during regression of the rhesus macaque corpus luteum

Our previous flow cytometry results demonstrated a significant increase in neutrophils, macrophages/monocytes, and natural killer (NK) cells in dispersed rhesus monkey corpora lutea (CL) after progesterone (P4) levels had fallen below 0.3 ng/ml for ≥3 days during the natural menstrual cycle. In this study, immunohistochemistry revealed the CD11b+ cells (neutrophils, macrophages/monocytes) present in the CL after luteal P4 synthesis ceased were distributed throughout the tissue. CD16+ cells (presumptive NK cells) were observed mainly near the vasculature in functional CL, until their numbers increased and they became widely distributed in regressing CL. To determine if the immune cells that enter luteal tissue during structural regression are functionally different from those that are present during peak function, CD11b+ or CD16+ populations were enriched from mid-late stage (functional) and regressing (days 1.8 ± 0.3 postmenses) CL using antibody-conjugated magnetic microbeads. Flow cytometry analyses revealed the majority of CD11b+ cells expressed CD14, a protein mainly produced by macrophages/monocytes. The antibody-enriched and depleted fractions were cultured for 24 h, and the media then analyzed for the production of 29 cytokines/chemokines. From the mid-late CL, the CD11b+-enriched fraction produced three cytokines/chemokines, whereas CD16+-enriched cells only produced the chemokine CCL2. However, CD11b +-enriched cells isolated from regressed CL produced eight cytokines/chemokines. The CD16+-enriched cells isolated from regressing CL produced significant levels of only three cytokines. Thus, the CD11b+ cells that appear in the rhesus macaque CL after functional regression produce several cytokines/chemokines that likely play a role in orchestrating structural regression.

Noni (Morinda citrifolia L.) fruit juice reverses age-related decline in neural-immune interactions in the spleens of old F344 rats

ETHNOPHARMACOLOGICAL RELEVANCE

Various parts of the tropical plant, Morinda citrifolia L. (Noni), have been widely used in traditional medicine in South and Southeast Asia for several centuries. The therapeutic effects of the noni are believed to be mediated through several phytochemicals such as anthraquinones, iridoid, fatty acid glycosides, alcohols, etc.

AIM OF THE STUDY

The aim of the study is to investigate the effects of Morinda citrifolia fruit juice (noni fruit juice; NFJ) on neural-immune interactions through the involvement of intracellular signaling pathways both in vitro and in vivo in the splenic lymphocytes of young and old male F344 rats.

MATERIAL AND METHODS

In the in vitro study, splenocytes from young and old F344 rats were isolated and treated with 0.0001-1% concentrations of NFJ for a period of 24h, while in the in vivo study, old F344 rats were orally administered (5ml/kg body weight) with NFJ (5%, 10% and 20%) twice daily for 60 days. After the treatment period, concanavalin A (Con A)-induced lymphocyte proliferation, cytokines (IL-2, IFN-γ, IL-6, and TNF-α) production, expression of tyrosine hydroxylase (p-TH), nerve growth factor (NGF), m-TOR, IκB-α, p-NF-κB (p50 and p65), p-ERK, p-Akt, p-CREB and lipid peroxidation, protein carbonyl formation, nitric oxide (NO) production were examined in the splenocytes.

RESULTS

In vitro NFJ incubation of splenic lymphocytes increased Con A-induced lymphocyte proliferation, IL-2 and IFN-γ production, and expression of p-ERK, p-Akt, and p-CREB in young and old rats. In vivo treatment of old rats with NFJ increased lymphoproliferation, IL-2 and IFN-γ production, the expression of p-TH, NGF, and NO production, and suppressed IL-6 production, lipid peroxidation, protein carbonyl formation, and the expression of IκB-α and p-NF-κB (p50) in the splenocytes.

CONCLUSION

Taken together, these results suggest that Morinda citrifolia fruit juice enhanced neural-immune interactions and cell survival pathways while inhibiting inflammatory processes that may be useful in the treatment of age-associated diseases.

Leukocyte Gene Expression and Plasma Concentration in Multiple Sclerosis: Alteration of Transforming Growth Factor-βs, Claudin-11, and Matrix Metalloproteinase-2

Multiple sclerosis is a neurodegenerative disease characterized by the present of leukocytes in the brain tissue and subsequently the formation of sclerotic plaques. Leukocytes penetration into the blood-brain barrier is related to several factors, such as, the conversion of leukocyte gene expression or plasma characteristics. In this frame, we explore alteration of matrix metalloproteinase-2 (MMP-2), transforming growth factor beta (TGF-β) family, and Claudin-11 (as a main myelin structural protein) in leukocytes and blood plasma of multiple sclerosis patients compared to the normal group. Blood samples were collected from thirteen men affected by MS and fifteen healthy men. Leukocyte gene expression was measured using real-time PCR and plasma parameters were examined by ELISA. The results of this study showed that the gene expression of Claudin-11 was significantly higher in MS group compared with normal. Interestingly, the MMP-2 pattern was similar to Claudin-11 and correlated positively with it. It was observed that, although the expressions of TGF-β1 and TGF-β2 are down-regulated in the leukocytes of subjects with MS, they showed higher levels of these cytokines in blood plasma. The plasma level of TGF-β3 in MS patients was higher than normal and correlated with Claudin-11 concentration. In conclusion, the aberrant pattern of Claudin-11, TGF-βs family, and MMP-2 expression in leukocytes of the MS patients was observed in this study. Moreover, the plasma levels of TGF-βs family increased in the MS group. The findings of this study provide clues for further investigations to assay MS pathogenesis.

Circulating leptin and NF-κB activation in peripheral blood mononuclear cells across the menstrual cycle

Using the menstrual cycle as a model, this study focused on longitudinal changes and associations within a physiological network known to play a role in female fertility, including, as biologically active nodes, NF-κB, leptin and adiponectin, β-carotene, adipose tissue, and progesterone. In 28 women, leptin, adiponectin, β-carotene, and progesterone concentrations, NF-κB p65 and p50 activation in peripheral blood mononuclear cells (known to possess estrogen, progesterone and leptin receptors), total body fat (TBF) and subcutaneous adipose tissue (SAT) mass were determined at early (T1) and late follicular (T2) and mid (T3) and late (T4) luteal phase. Leptin and adiponectin concentrations were higher, while NF-κB p65 activation was lower at T3 compared with T1. NF-κB p65 activation was inversely related to leptin concentrations at T1, T3, and T4. β-Carotene was inversely related to leptin (T1,T2,T4) and SAT (T1,T3,T4). NF-κB p50 activation was inversely related to TBF (T4) and SAT (T3,T4), and leptin was positively related to TBF and SAT (T1-T4). Progesterone was inversely related to leptin (T2,T3), adiponectin (T3), TBF (T3,T4), and SAT (T2,T3,T4). By providing evidence of luteal phase-specific reduced NF-κB p65 activation in women under physiological conditions, this study bridges the gap between existing evidence of a Th1-Th2 immune response shift induced by reduced NF-κB p65 activation and a Th1-Th2 shift previously observed at luteal phase. For the first time, inverse regressions suggest inhibitory effects of leptin on NF-κB p65 activation at luteal phase, along with inhibitory effects of leptin as well as adiponectin on progesterone production in corpus luteum. © 2016 The Authors BioFactors published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology. 24(4):376-387, 2016.

Estrogen-induced neuroprotective and anti-inflammatory effects are dependent on the brain areas of middle-aged female rats

BACKGROUND

Reproductive aging in females is characterized by fluctuations and precipitous decline in estrogen levels, which may lead to reduction in cognitive function and age-associated neurodegenerative disorders. The nature of estrogen-mediated neuronal plasticity is unknown during reproductive aging. We hypothesize that estrogen treatment of early middle-aged ovariectomized rats may exert specific effects in the brain by modulating signaling pathways regulating metabolic enzymes, inflammatory markers, antioxidant status, cholinergic function and survival signals.

PURPOSE

To investigate the mechanisms of estrogen-induced effects on neuroprotection and neuroinflammation through the involvement of intracellular signaling pathways in brain areas of ovariectomized (OVX) middle-aged (MA) female rats.

METHODS

Ovariectomized early MA female Sprague-Dawley rats (n=8/group) were implanted with 17β-estradiol (E2) 30-day release pellets (0.6μg and 300μg). At the end of the treatment period, frontal cortex (FC), striatum (STR), medial basal hypothalamus (MBH), and hippocampus (HP) were isolated and examined for the expression of tyrosine hydroxylase (p-TH), nerve growth factor (NGF), p-NF-κB (p50 and p65)and p-ERK, p-CREB, p-Akt, and activities of cholinesterases and antioxidant enzymes, key regulatory enzymes of metabolic pathways, and nitric oxide production.

RESULTS

E2 enhanced p-TH expression in FC and HP, reduced NGF expression in HP, and suppressed p-NF-κB expression in FC and STR. It also increased the expression of molecular markers (p-ERK, p-CREB and p-Akt), and nitric oxide production in various brain areas, while differentially regulating the activities of metabolic enzymes and cholinesterases.

CONCLUSION

Estrogen modulates the neural and inflammatory factors, and intracellular markers depending on the brain areas that may influence differential remodeling of neuronal circuitry which can be used to develop therapeutic strategies in cognitive impairment and neurodegenerative disorders in aging.

Osteoimmunology: from mice to humans

The immune system has been recognized as one of the most important regulators of bone turnover and its deregulation is implicated in several bone diseases such as postmenopausal osteoporosis and inflammatory bone loss; recently it has been suggested that the gut microbiota may influence bone turnover by modulation of the immune system. The study of the relationship between the immune system and bone metabolism is generally indicated under the term 'osteoimmunology'. The vast majority of these studies have been performed in animal models; however, several data have been confirmed in humans as well: this review summarizes recent data on the relationship between the immune system and bone with particular regard to the data confirmed in humans.

Effects of Diabetes on Post-Menopausal Rat Submandibular Glands: A Histopathological and Stereological Examination

OBJECTIVE

The menopause in elderly women is a physiological process where ovarian and uterine cycles end. Diabetes means higher blood glucose level that is a metabolic disease and has an increased incidence. The aim of the study was to examine the single or combined effects of menopause and diabetes that causes pathophysiological processes on submandibular gland on ovariectomy and diabetes induced rat models.

MATERIALS AND METHODS

Sprague Dawley twelve weeks old female (n=24) rats were divided randomly into four groups; Healthy control group (n=6), diabetic group (DM, n=6), ovariectomized group (OVX, n=6), post ovariectomy diabetes induced group (DM+OVX, n=6) individually. Histopathological, histochemical and stereological analyses were done in these groups.

RESULTS

Significant neutrophil cell infiltrations and myoepithelial cell proliferations, granular duct and seromucous acini damages and changes in the content of especially seromucous acini secretion in DM and/or OVX groups and distinctive interstitial and striated duct damages in post ovariectomy diabetes induced group were detected. Alterations ingranular ducts hypertrophic and in seromucous acini atrophic were determined in DM and/or OVX groups.

CONCLUSION

The results revealed the pathophysiological processes that lead to morphological and functional alterations on the cellular level in submandibular glands. The molecular mechanisms related with pathogenesis of diabetes and menopause need further investigation.

Estrogen upregulates inflammatory signals through NF-κB, IFN-γ, and nitric oxide via Akt/mTOR pathway in the lymph node lymphocytes of middle-aged female rats

The alterations in the secretion of sex steroids, especially estrogen, in females throughout reproductive life and its decline with age alters the functions of the neuroendocrine-immune network and renders them susceptible to age-related diseases and cancers. This study investigates the mechanisms of estrogen-induced alterations in cell-mediated immune and inflammatory responses in the lymphocytes from lymph nodes (axillary and inguinal) of ovariectomized (OVX) middle-aged female rats. Ovariectomized middle-aged (MA) Sprague-Dawley female rats (n=8) were implanted with 17β-estradiol (E2) 30-day release pellets (0.6 and 300μg). At the end of the treatment period, lymph nodes (axillary and inguinal) were isolated and examined for serum 17β-estradiol, lymphoproliferation, cytokine production, expression of p-Akt, p-mTOR, p-IκB-α and p-NF-κB (p50 and p65), extent of lipid peroxidation, nitric oxide (NO) production, cytochrome c oxidase activity and reactive oxygen species (ROS) production. There was an OVX-related decline in serum 17β-estradiol level, Con A-induced lymphoproliferation, p-Akt and p-mTOR expression, and cytochrome c oxidase (COX) activity. E2 supplementation increased serum 17β-estradiol level, lymphoproliferation, expression of p-Akt, p-mTOR, p-IκB-α and p-NF-κB (p50 and p65), lipid peroxidation, IFN-γ, TNF-α, ROS and NO production, while it decreased IL-6 production. E2 mediates inflammatory responses by increasing the levels of NO and TNF-α by up regulating IFN-γ and simultaneously promotes aging through the generation of free radicals as reflected by increased lipid peroxidation and ROS production in lymph nodes. These findings may have wide implications to immunity and inflammatory disorders including autoimmune diseases predominantly prevalent in females.

Tracing the trajectory of behavioral impairments and oxidative stress in an animal model of neonatal inflammation

Exposure to early-life inflammation results in time-of-challenge-dependent changes in both brain and behavior. The consequences of this neural and behavioral reprogramming are most often reported in adulthood. However, the trajectory for the expression of these various changes is not well delineated, particularly between the juvenile and adult phases of development. Moreover, interventions to protect against these neurodevelopmental disruptions are rarely evaluated. Here, female Sprague-Dawley rats were housed in either environmental enrichment (EE) or standard care (SC) and their male and female offspring were administered 50 μg/kg i.p. of lipopolysaccharide (LPS) or pyrogen-free saline in a dual-administration neonatal protocol. All animals maintained their respective housing assignments from breeding until the end of the study. LPS exposure on postnatal days (P) 3 and 5 of life resulted in differential expression of emotional and cognitive disruptions and evidence of oxidative stress across development. Specifically, social behavior was reduced in neonatal-treated (n)LPS animals at adolescence (P40), but not adulthood (P70). In contrast, male nLPS rats exhibited intact spatial memory as adolescents which was impaired in later life. Moreover, these males had decreased prefrontal cortex levels of glutathione at P40, which was normalized in adult animals. Notably, EE appeared to offer some protection against the consequences of inflammation on juvenile social behavior and fully prevented reduced glutathione levels in the juvenile prefrontal cortex. Combined, these time-dependent effects provide evidence that early-life inflammation interacts with other developmental variables, specifically puberty and EE, in the expression (and prevention) of select behavioral and molecular programs.

Persistent organic pollutants and obesity: are they potential mechanisms for breast cancer promotion?

Dietary ingestion of persistent organic pollutants (POPs) is correlated with the development of obesity. Obesity alters metabolism, induces an inflammatory tissue microenvironment, and is also linked to diabetes and breast cancer risk/promotion of the disease. However, no direct evidence exists with regard to the correlation among all three of these factors (POPs, obesity, and breast cancer). Herein, we present results from current correlative studies indicating a causal link between POP exposure through diet and their bioaccumulation in adipose tissue that promotes the development of obesity and ultimately influences breast cancer development and/or progression. Furthermore, as endocrine disruptors, POPs could interfere with hormonally responsive tissue functions causing dysregulation of hormone signaling and cell function. This review highlights the critical need for advanced in vitro and in vivo model systems to elucidate the complex relationship among obesity, POPs, and breast cancer, and, more importantly, to delineate their multifaceted molecular, cellular, and biochemical mechanisms. Comprehensive in vitro and in vivo studies directly testing the observed correlations as well as detailing their molecular mechanisms are vital to cancer research and, ultimately, public health.

Influence of menstrual cycle on the expression of clock genes in peripheral blood mononuclear cells in Macaca fascicularis

OBJECTIVE

To investigate whether the expression patterns of periphery clock genes were influenced by menstrual cycle in a monkey model.

STUDY DESIGN

In this preliminary study, the expression patterns of four clock genes (Bmal1, Clock, Cry1 and Per2) in peripheral blood mononuclear cells (PBMCs) from 6 female Macaca fascicularis in menstrual, late follicular and mid luteal phases of menstrual cycle were determined by qrt-PCR.

RESULTS

Bmal1 and Per2 mRNA levels were found to exhibit significant diurnal rhythms in all phases of the menstrual cycle. The expression of Cry1 mRNA was statistically rhythmic in late follicular and mid luteal phases. A main effect of menstrual cycle existed on the rhythms of Bmal1, Cry1 and Per2 expression, but not Clock expression. No significant differences were detected between menstrual phase and late follicular phase in all clock genes. Significant differences were found on the expression of Bmal1, Cry1 or Per2 mRNA between late follicular phase and mid luteal phase, when no difference existed in estrogen level, indicating the role of progesterone on biological clock gene expression. Furthermore, the peak of Bmal1 mRNA level slightly advanced in mid luteal phase compared with that in menstrual and late follicular phases.

CONCLUSION

The expression patterns of clock genes in PBMCs were influenced by menstrual cycle, potentially by the change of progesterone levels, and this effect maybe correlated with early pregnancy.

Estrogen modulates in vitro T cell responses in a concentration- and receptor-dependent manner: effects on intracellular molecular targets and antioxidant enzymes

Estrogen is a key hormone in facilitating ovulation and maintenance of pregnancy in young females and subsequent decline in its production contributes to the development of age-associated disorders such as hormone-dependent cancer, osteoporosis, and cardiovascular diseases. The mechanisms through which estrogen promotes female-specific diseases with advancing age are unclear especially, its effects on immune system which is vital for the maintenance of homeostasis and health. Although the diverse effects of estrogen on Th immunity (Th1 vs. Th2) have been characterized in several cell-types and animal models, there is no direct mechanistic study to understand its immunomodulatory actions. The purpose of this study is to investigate whether the in vitro effects of 17β-estradiol on lymphocytes from the spleen influence cell-mediated immune responses based on its concentration and type of estrogen receptors (ERs) and to assess its mechanism of action at the cellular level. Lymphocytes from the spleens of young Sprague-Dawley rats were isolated and incubated with various concentrations of 17β-estradiol (10(-6)-10(-14)M) and specific ERα- and β-agonists (10(-6)M, 10(-8)M and 10(-10)M) without or with concanavalin A (Con A) to measure T lymphocyte proliferation, IFN-γ and IL-2 production, p-ERK 1/2, p-CREB, and p-Akt, activities of antioxidant enzymes[superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)], and nitric oxide (NO) production. The specificity of ER-mediated actions in lymphocytes was examined by coincubation with nonspecific ER antagonists ICI(182,780) or tamoxifen. Lower concentrations of 17β-estradiol enhanced proliferation of T lymphocytes and IFN-γ production without or with Con A stimulation but had no effect on IL-2 production. ERα and ERβ agonists induced an increase in T cell proliferation and IFN-γ production and these effects were inhibited by tamoxifen. ERβ agonist alone enhanced IL-2 production by the lymphocytes. Coincubation with 17β-estradiol and ERα- and β-agonists augmented p-ERK 1/2, p-CREB, and p-Akt expression in the lymphocytes and tamoxifen reversed the ER agonist-induced effects on these molecular targets. Estrogen increased the activities of SOD, CAT, and GPx in both non-stimulated and Con A-stimulated splenocytes in a concentration-dependent manner. Both ERα- and β-agonists enhanced CAT and GPx activity while ERα-agonist decreased SOD activity and ERβ-agonist increased SOD activity. The effects of ER agonists on the antioxidant enzymes were reversed by ICI(182,780). Coincubation of lower doses of 17β-estradiol with Con A and both ER agonists enhanced NO production while higher dose of estrogen with Con A and ERα agonist suppressed its production and these effects were reversed by tamoxifen. Taken together, these results suggest that the effects of estrogen on the cell-mediated immune responses are dependent upon its concentrations and mediated through specific estrogen receptors involving intracellular signaling pathways and antioxidant enzymes.