Plasma beta-endorphin and natural killer cell activity in major depression: a preliminary study

Association between cardiovascular disease and risk of female sexual dysfunction: a systematic review and meta-analysis

AIMS

Female sexual dysfunction (FSD) is a considerably underestimated condition. It has been repeatedly reported that patients with cardiovascular diseases (CVD) may suffer from an increased risk of FSD. However, there is still a lack of comprehensive and systematic evaluation of various CVD and FSD. We aimed to elucidate the association between CVD and FSD through a comprehensive literature review and meta-analysis.

METHODS AND RESULTS

The PubMed, Scopus, Embase, and Cochrane Library databases were systematically searched from inception to 28 February 2023. We identified all relevant studies reporting the risk of FSD in subjects with or without CVD. The associations between CVD and the risk of FSD were assessed by calculating pooled odds ratios (ORs) (cross-sectional studies) and risk ratios (RRs) (longitudinal studies) with 95% CIs. We employed random-effects models to account for potential heterogeneity, and the quality of the included studies was assessed using the Newcastle-Ottawa Scale. Fifty-four articles with 148 946 individuals were included in our meta-analysis. Compared with control subjects, subjects with CVD had a 1.51-fold increased risk of FSD (OR 1.51 95% CI, 1.34-1.69, P < 0.001, heterogeneity I2 = 91.4%, P < 0.001). Subgroup analyses indicated that the association between CVD and FSD remained significant in longitudinal studies (RR 1.50 95% CI, 1.21-1.86, P < 0.001, heterogeneity I2 = 86.7%, P < 0.001). Particularly, hypertension (OR 1.41 95% CI, 1.23-1.62, P < 0.001, heterogeneity I2 = 82.7%, P < 0.001), stroke (OR 1.81 95% CI, 1.54-2.12, P < 0.001, heterogeneity I2 = 0%, P < 0.423), and myocardial infarction (OR 2.07 95% CI, 1.60-2.67, P < 0.001 heterogeneity I2 = 82.4%, P < 0.001) were significantly associated with FSD. Meta-regression revealed that the primary sources of heterogeneity in FSD are attributable to adjustments for covariates, study design, and study population.

CONCLUSION

Our meta-analysis indicated that patients with CVD suffer from a greater risk of developing FSD. Meanwhile, we validated these findings in longitudinal queues. Notably, conditions such as hypertension, stroke, and myocardial infarction demonstrated a significant association with the incidence of FSD.

Sexual activity in a large representative cohort of Polish men: Frequency, number of partners, correlates, and quality of life

INTRODUCTION

Sexual activity of men has been evaluated at the population-level in different regions of the world. However, reliable data are lacking for Eastern Europe. Therefore, the aim of this study was to analyze the frequency of sexual activity and the number of sexual partners in a large representative cohort of Polish men.

METHODS

We performed a cross-sectional investigation with computer-assisted web interviews. Participants were stratified by age (≥18 years) and place of residence. The most recent population census was used to produce a population-representative sample of respondents. Men's sexual activity was then correlated with multiple variables.

RESULTS

We enrolled 3001 men, representative for age and place of residence, including adequate proportions of respondents from urban and rural areas. Most Polish men were sexually active, predominantly having had sex at least weekly with one partner. Almost 18% of respondents declined sexual intercourse and/or sexual partner in the prior year. The highest sexual activity was observed for men 35-44-years-old (for sex frequency) and 18-24-years-old (for partner number), living in medium-sized cities, employed, and married (for sex frequency) or divorced (for partner number). Erectile dysfunction negatively affected the frequency of sexual activity and lowered the number of sexual partners, although premature ejaculation did not have any effect. Frequency of sexual activity and number of sexual partners correlated well with psychological distress, quality of sex life, and overall life quality. Whereas lifestyle habits including smoking and alcohol intake decreased the likelihood of sexual activity, all analyzed comorbidities did not affect sex life.

CONCLUSIONS

This study of men's sexual activity was the first population-representative and nationwide investigation performed in Poland. Most Polish men were sexually active and sexual activity correlated with multiple variables including sociodemographic factors, erectile functioning, mental distress, overall and sex-specific quality of life, and lifestyle habits.

What Influences Coital Frequency Among Chinese Men?: A Cross-Sectional Study

INTRODUCTION

There are many Western reports on factors influencing coital frequency among men. However, no articles could be found about the factors influencing sexual activity among Chinese men.

AIM

The aim of this study was to identify the factors that influence the coital frequency of Chinese men.

MAIN OUTCOME MEASURES

The main outcome measures included self-reported monthly coital frequency, age, occupation, education level, andrology-related scales and dietary habits.

METHODS

Data for 1,407 men aged 18-79 years were collected in the Health Management Center of the Third Xiangya Hospital of Central South University from January 2019 to May 2019. The respondents completed the questionnaires independently or with the help of an interviewer (who read or explained the questionnaires to them) to analyse the factors that influence coital frequency.

RESULTS

In the previous 6 months, the sample had a mean monthly coital frequency (±SD) of 4.34 ± 3.18. Univariate logistic regression results indicated that the number of children (P = 0.004), IIEF-5 scores (P <0.001), EHSs (P <0.001) and frequency of milk consumption (P = 0.001) were associated with more frequent sexual activity. These statistical associations did not change after further adjustment for age, occupation, and reproductive history. We observed that the frequency of sexual activity showed an increasing trend with a greater number of children, higher IIEF-5 scores, higher EHSs and greater frequency of milk consumption (test for trend, P<0.05). Both univariate and multivariate analysis results indicated that the frequency of sexual activity decreased with increasing age (test for trend, P<0.001).

CONCLUSION

The coital frequency of Chinese men is associated with erectile function, anthropometric parameters, age, occupation, and dietary habits. Xiang Y, Peng J, Yang J, et al. What Influences Coital Frequency Among Chinese Men?: A Cross-Sectional Study. Sex Med 2021;9:100363.

Roles of β-Endorphin in Stress, Behavior, Neuroinflammation, and Brain Energy Metabolism

β-Endorphins are peptides that exert a wide variety of effects throughout the body. Produced through the cleavage pro-opiomelanocortin (POMC), β-endorphins are the primarily agonist of mu opioid receptors, which can be found throughout the body, brain, and cells of the immune system that regulate a diverse set of systems. As an agonist of the body's opioid receptors, β-endorphins are most noted for their potent analgesic effects, but they also have their involvement in reward-centric and homeostasis-restoring behaviors, among other effects. These effects have implicated the peptide in psychiatric and neurodegenerative disorders, making it a research target of interest. This review briefly summarizes the basics of endorphin function, goes over the behaviors and regulatory pathways it governs, and examines the variability of β-endorphin levels observed between normal and disease/disorder affected individuals.

In major depression, increased kappa and mu opioid receptor levels are associated with immune activation

OBJECTIVE

This study was carried out to delineate differences between major depressive disorder (MDD) and healthy controls in dynorphin and kappa opioid receptor (KOR) levels in association with changes in the β-endorphin - mu opioid receptor (MOR) and immune-inflammatory system.

METHODS

The present study examines dynorphin, KOR, β-endorphin, MOR, interleukin (IL)-6 and IL-10 in 60 drug-free male participants with MDD and 30 age-matched healthy males.

RESULTS

Serum dynorphin, KOR, β-endorphin and MOR are significantly higher in MDD as compared to controls. The increases in the dynorphin/KOR system and β-endorphin/MOR system are significantly intercorrelated and are both strongly associated with increased IL-6 and IL-10 levels. Dynorphin, β-endorphin, KOR and both cytokines showed a good diagnostic performance for MDD versus controls with a bootstrapped (n = 2000) area under the receiver operating curve of 0.972. The dynorphin/KOR system is significantly decreased in depression with comorbid nicotine dependence.

CONCLUSION

Our findings suggest that, in MDD, immune activation is associated with a simultaneous activation of dynorphin/KOR and β-endorphin/MOR signaling and that these opioid systems may participate in the pathophysiology of depression by (a) exerting immune-regulatory activities attenuating the primary immune response and (b) modulating reward responses and mood as well as emotional and behavioural responses to stress.

Declines in Sexual Activity and Function Predict Incident Health Problems in Older Adults: Prospective Findings from the English Longitudinal Study of Ageing

The objective of this study was to investigate cross-sectional and longitudinal associations between declines in sexual activity and function and health outcomes in a large population-based sample of older adults. Data were from 2577 men and 3195 women aged ≥ 50 years participating in the English Longitudinal Study of Ageing. Past-year changes in sexual desire, frequency of sexual activity, and ability to have an erection (men)/become sexually aroused (women) were assessed at baseline by self-completion questionnaire. Health outcomes (self-rated health, limiting long-standing illness, doctor-diagnosed diseases of the vascular system, and cancer) were self-reported at baseline (2012/2013) and 4-year follow-up (2016/2017). Data were analyzed using logistic regression, adjusted for sociodemographics, health behaviors, and depressive symptoms. Prospectively, men who reported a decline in sexual desire had higher odds of incident limiting long-standing illness (OR 1.41, 95% CI 1.04-1.91) and incident cancer (OR 1.63, 95% CI 1.06-2.50) than those who maintained their sexual desire. Men who reported a decline in the frequency of sexual activities had higher odds of deterioration in self-rated health (OR 1.47, 95% CI 1.04-2.08) and incident limiting long-standing illness (OR 1.69, 95% CI 1.20-2.37). In women, a decline in frequency of sexual activities was associated with deterioration of self-rated health (OR 1.64, 95% CI 1.07-2.51). Erectile dysfunction was longitudinally associated with poorer health outcomes including incident cancer (OR 1.73, 95% CI 1.11-2.70), coronary heart disease (OR 2.29, 95% CI 1.29-4.07), and fair/poor self-rated health (OR 1.66, 95% CI 1.19-2.32). Practitioners should be mindful that a decline in sexual activity, desire, or function in older age may be an important indicator of future adverse health outcomes.

Associations between sexual activity and weight status: Findings from the English Longitudinal Study of Ageing

Objective

To investigate the association between weight status and sexual activity in middle-aged and older adults.

Methods

Cross-sectional analysis on Wave 6 (2012/13) of the English Longitudinal Study of Ageing. Data were from 2,200 men and 2,737 women aged ≥50 years (mean 68.2 years). The explanatory variable was weight status, defined as normal-weight (BMI: ≤24.9), overweight (BMI: 25.0–29.9) or obese (BMI: ≥30) based on objective measurements of height and weight. Outcome variables were any self-reported sexual activity in the last year (yes/no) and, if yes, frequency of sexual intercourse in the last month. Covariates included a range of sociodemographic, lifestyle, and health-related variables. Associations were analysed using binary (past-year sexual activity) and ordinal (frequency of past-month sexual intercourse) logistic regression models.

Results

The majority (73.3%) of men and half (50.0%) of women reported any sexual activity in the last year. The odds of reporting any sexual activity in the last year did not differ significantly by weight status in either men or women. However, among those who were sexually active, men with overweight (OR = 1.45, 95% CI 1.15–1.81, p = 0.002) or obesity (OR = 1.38, 95% CI 1.07–1.77, p = 0.015), and women with overweight (OR = 1.34, 95% CI 1.05–1.71, p = 0.017) reported significantly more frequent sexual intercourse in the last month compared with those who had a BMI in the normal-weight range, after adjustment for covariates.

Conclusion

Older adults with overweight or obesity who are sexually active engage in more frequent sexual activity than those who are normal weight.

Interaction between serotonin 5-HT1A receptors and beta-endorphins modulates antidepressant response

Interactions between serotonergic and the endogenous opioid systems have been suggested to be involved in the etiopathogenesis of depression and in the mechanism of action of antidepressants. Activation of serotonin 5-HT1A receptors has been shown to increase plasma beta-endorphin (beta-END) levels in animal studies and in healthy humans.

OBJECTIVES

To assess interaction abnormalities between 5-HT1A receptors and the endogenous opioid system in patients with major depression and the possible modulating effect of citalopram.

METHODS

The beta-END response to the 5-HT1A receptor agonist, buspirone (30 mg), was measured in 30 patients with major depression and in 30 age- and sex-matched healthy controls before and after an 8-week treatment with citalopram. Pre-treatment score of the Hamilton Rating Scale for Depression (HRSD) was >or=17. Antidepressant response was defined by a 50% decrease in the HRSD. Pre- and post-treatment maximum peak response (Deltamax) and the area under the curve (AUC) of beta-END response were compared. Three time points were measured (60, 90 and 120 min). We also examined the correlations between the beta-END response and the antidepressant response. Buspirone plasma levels were not measured.

RESULTS

At baseline, beta-END response was similar in patients and controls. After 8 weeks of citalopram treatment depressed patients showed a significant decrease in the beta-END response (Deltamax: p<.001; AUC: p<.001). A significant correlation between the beta-END reduction in the response and the reduction in the HRSD score (r=.656; p<.001) was observed.

CONCLUSIONS

Changes in interaction between 5-HT1A receptor system and the endogenous opioid system may play a role both in the mechanism of action and response to antidepressant drugs.

Cholecystokinin and endogenous opioid peptides: interactive influence on pain, cognition, and emotion

It is well documented that stressful life experiences contribute to the etiology of human mood disorders. Cholecystokinin (CCK) is a neuropeptide found in high concentrations throughout the central nervous system, where it is involved in numerous physiological functions. A role for CCK in the induction and persistence of anxiety and major depression appears to be conspicuous. While increased CCK has been associated with motivational loss, anxiety and panic attacks, an increase in mesocorticolimbic opioid availability has been associated with coping and mood elevation. The close neuroanatomical distribution of CCK with opioid peptides in the limbic system suggests that there may be an opioid-CCK link in the modulation and expression of anxiety or stressor-related behaviors. In effect, while CCK induces relatively protracted behavioral disturbances in both animal and human subjects following stressor applications, opioid receptor activation may change the course of psychopathology. The antagonistic interaction of CCK and opioid peptides is evident in psychological disturbances as well as stress-induced analgesia. There appears to be an intricate balance between the memory-enhancing and anxiety-provoking effects of CCK on one hand, and the amnesic and anxiolytic effects of opioid peptides on the other hand. Potential anxiogenic and mnemonic influences of site-specific mesocorticolimbic CCK and opioid peptide availability, the relative contributions of specific CCK and opioid receptors, as well as the time course underlying neuronal substrates of long-term behavioral disturbances as a result of stressor manipulations, are discussed.

Sleep quality and health-related quality of life in HIV-infected African-American women of childbearing age

A descriptive, correlational design was used to examine the associations of sleep quality and stage of illness with health-related quality of life (HRQOL) in HIV-infected African-American women. Participants were recruited from 12 health clinics and AIDS service organizations (ASO) in Georgia, North Carolina, and South Carolina. The sample consisted of 144 African-American women who ranged in age from 20 to 48 years (m = 34.8, SD = 6.8). The Pittsburgh Sleep Quality Index (PSQI) and the Medical Outcomes Short-Form Health Survey (SF-36) were administered. Participants were categorized as good sleepers (PSQI global score < 7) or poor sleepers (PSQI global score > or = 7) using the median global sleep quality score. Differences in HRQOL between good and poor sleepers, as measured by the SF-36, were tested using MANOVA. Good sleepers scored significantly higher (p < 0.0001) for each SF-36 quality of life dimension and the mental and physical health summary scores. Multiple regression analysis indicated that sleep quality is associated with HRQOL, independent of the individual's stage of illness, more so with mental HRQOL than with physical HRQOL. The results suggest that treatment for poor sleep quality should be a primary concern for the treatment of HIV infection and a means for improving HRQOL.

Are exercise stress tests appropriate for assessing myocardial ischemia in patients with major depressive disorder?

BACKGROUND

Major depressive disorder (MDD) disproportionately affects patients with coronary artery disease (CAD). Evidence of myocardial ischemia with electrocardiography (ECG) or single-photon-emission-computed-tomography (SPECT) assessments during exercise testing is an important determinant of CAD prognosis. However, many key symptoms of MDD, such as reduced interest in daily activities, lack of energy, and fatigue, may affect exercise performance and the detection of ischemia in patients with MDD. This study evaluated the extent to which MDD and depressive symptomatology moderate exercise test performance and compared the ability of ECG versus SPECT for detecting ischemia in 1367 consecutive patients who underwent exercise testing.

METHODS

All patients underwent a brief, structured psychiatric interview (PRIME-MD) and completed the Beck Depression Inventory (BDI) on the day of their exercise (treadmill) test.

RESULTS

A total of 183 patients (13%) met diagnostic criteria for MDD. Patients with MDD achieved a significantly lower percent of maximal predicted heart rate (%MPHR), exhibited lower peak exercise mets, and spent less time exercising compared with patients without MDD (all P values <.05). BDI scores were also negatively correlated with all 3 indices of exercise performance (all P values <.01). There were no differences in rates of SPECT ischemia in patients with MDD (40%) versus patients without MDD (45%; P =.23); however, rates of ECG ischemia were significantly lower (30%) in patients with MDD than in patients without MDD (48%; P <.0001).

CONCLUSIONS

Results suggest that patients with CAD who have MDD, depressive symptomatology, or both exhibit poor exercise tolerance and performance and that ECG, as compared with SPECT, may not be as reliable in detecting ischemia in patients who are depressed.

The relationship of depression and stressors to immunological assays: a meta-analytic review

This is a broad meta-analysis of the relations of both depression and stressors to immunological assays. The number of study samples (greater than 180) and measures (greater than 40) is much more extensive than any so far. Analyses are done by both fixed and random effects. By a fixed-effects analysis, both major depression and naturally occurring acute stressors are associated with (1) an overall leukocytosis, (2) mild reductions in absolute NK-cell counts and relative T-cell proportions, (3) marginal increases in CD4/CD8 ratios, and (4) moderate decreases in T- and NK-cell function. However, the degree of heterogeneity of the studies' results raises questions about their robustness. Therefore, we also did the first random effects analysis to estimate what is likely to appear in future studies. For depression, the analysis showed the immunological correlates included (1) an overall leukocytosis, manifesting as a relative neutrophilia and lymphoenia; (2) increased CD4/CD8 ratios; (3) increased circulating haptoglobin, PGE(2), and IL-6 levels; (4) reduced NK-cell cytotoxicity; and (5) reduced lymphocyte proliferative response to mitogen. For stressors, the random effects analysis showed that future studies are likely to find the following effects: (1) an overall leukocytosis, manifesting as an absolute lymphocytosis; (2) alterations in cytotoxic lymphocyte levels, CD4/CD8 ratios, and natural killer cell cytotoxicity with the direction of change depending on the chronicity of the stressor; (3) a relative reduction of T-cell levels; (3) increased EBV antibody titers; (4) reduced lymphocyte proliferative response and proportion of IL-2r bearing cells following mitogenic stimulation; and (5) increased leukocyte adhesiveness. The random-effects analysis revealed that for both major depression and naturally occurring stressors the following effects are shared: leukocytosis, increased CD4/CD8 ratios, reduced proliferative response to mitogen, and reduced NK cell cytotoxicity. The implications for these findings for disease susceptibility and the pathophysiology of these conditions is discussed.

Effect of acute lipopolysaccharide administration on (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2 aminopropane-induced wet dog shake behavior in rats: comparison with body weight change and locomotor activity

1. Several reports have shown that serotonin (5-HT)2A receptor density and its function are altered after physiological or pharmacological stress. To examine whether an acute administration of lipopolysaccharide (LPS), a bacterial endotoxin, affected 5-HT2A receptor function, wet dog shakes of male Wistar rats were observed after a subcutaneous injection of DOI, a 5-HT2A receptor agonist following LPS treatment. Body weight change and locomotor activity were also observed. 2. DOI (1 mg/kg)-induced WDS significantly decreased after 400 or 1000 microg/kg LPS treatment compared with that of control rats 1 and 3 hr after injection, and WDS completely recovered 8 hr after LPS treatment. Treatment with 10 mg/kg indomethacin (IND) or 1 mg/kg naltrexone (NLTX) canceled the effect of 400 microg/kg LPS on DOI-induced WDS. 3. Body weight decrease was significantly greater in LPS-treated rats compared with control rats 3, 5 and 8 hr after treatment. Treatment with IND (10 mg/kg) significantly recovered the reduction in body weight induced by 400 microg/kg LPS. Treatment with NLTX (1 mg/kg) also prevented the LPS effect on body weight decrease. 4. Eight hr after treatment with LPS (400 microg/kg), the rats showed significant attenuation of locomotor activity. IND (10 mg/kg) treatment abolished the inhibitory effect of LPS on locomotor activity, and NLTX (1 mg/kg) also improved the decrease in locomotion 8 hr after LPS treatment. 5. Plasma tumor necrosis factor (TNF)-alpha concentration dramatically increased 1 hr after the injection of 400 microg/kg LPS, and returned almost to the basal level 3 hr later. Next, rats were injected with 50 microg/kg TNF-alpha intraperitoneally, and body weight change and DOI-induced WDS was determined 3 hr after TNF-alpha injection. Body weight loss was significantly greater in rats treated with TNF-alpha. On the other hand, DOI-induced WDS was not altered when rats were treated with TNF-alpha. 6. These results suggest that acute treatment with LPS inhibited 5-HT2A receptor-mediated behavior via cyclooxygenase and opioid receptor activation, but that the inhibition of the WDS by LPS appears to be independent of TNF-alpha production.

Serotonin-mediated increases in the extracellular levels of beta-endorphin in the arcuate nucleus and nucleus accumbens: a microdialysis study

Although the involvement of both endogenous opioid and serotonergic systems in modulation of pain and emotion was suggested, the neurochemical interaction between these systems in the brain has not previously been studied directly. Herein, the effects of the local application of serotonin (5-HT) and fluoxetine (a 5-HT reuptake inhibitor) on extracellular levels of beta-endorphin in the arcuate nucleus and nucleus accumbens were assessed in freely moving rats using in vivo microdialysis. The mean basal concentrations of beta-endorphin in dialysates obtained from the arcuate nucleus and nucleus accumbens were 259.9 and 143.3 pM, respectively. Specific lesion of the serotonergic system by 5,7-dihydroxytryptamine (5,7-DHT) caused a significant decrease in these dialysate beta-endorphin levels. When 5-HT (0.25-5 microM) was added to the perfusion solution, the levels of beta-endorphin in the dialysate from the arcuate nucleus increased (186-296% of baseline), in a concentration-dependent manner. In the nucleus accumbens, 0.5 and 2 microM 5-HT in the perfusion fluid did not affect the levels of beta-endorphin in the dialysate, whereas 5 and 10 microM 5-HT caused an increase of approximately 190% of baseline. When fluoxetine (250 microM) was present in the perfusing solution, the levels of beta-endorphin in the dialysates from the arcuate nucleus and nucleus accumbens increased two- to threefold. This effect was not obtained in the 5,7-DHT-lesioned rats. Thus, 5-HT, either endogenously or exogenously delivered, appears to facilitate the release of beta-endorphin in the arcuate nucleus and nucleus accumbens. This indication of an interaction between serotonergic and endorphinic systems may be relevant for assessing pain and mood disorder circuits and the mode of action of antidepressant drugs.

Pathways linking major depression and immunity in ambulatory female patients

OBJECTIVES

The goals of this study were to investigate whether depression is associated with cellular immunity in ambulatory patients and to identify neuroendocrine and behavioral pathways that might account for this relationship.

METHODS

We studied 32 women who met Diagnostic and Statistical Manual of Mental Disorder, fourth edition, criteria for major depressive disorder and 32 healthy female control subjects. The groups were matched for age and ethnicity. None were taking medication, and all were free of disease involving the immune system.

RESULTS

Depressed subjects had reduced proliferative responses to the mitogens concanavalin A and phytohemagglutinin compared with control subjects. Natural killer cell activity was reduced among older depressed subjects but enhanced among younger depressed subjects. Although depression was associated with elevated circulating levels of norepinephrine and estradiol, these hormones could not account for the immunologic differences between depressed and control subjects. Depression was also associated with greater tobacco and caffeine consumption, less physical activity, and poorer sleep quality. Mediational analyses were consistent with physical activity acting as a pathway through which depression was associated with reduced lymphocyte proliferation.

CONCLUSIONS

Ambulatory patients with mild to moderately severe depression exhibit reduced mitogen-stimulated lymphocyte proliferative responses and altered natural killer cell cytotoxicity. The relationship between depression and proliferative responses may be mediated by physical activity.

Tumor necrosis factor-alpha: a continuum of liability between insulin-dependent diabetes mellitus, non-insulin-dependent diabetes mellitus and carcinoma (review)

In this review, tumor necrosis factor-alpha (TNF-alpha) is identified as the uniting principle linking the pathogenesis of insulin-dependent diabetes mellitus (IDDM), non-insulin dependent diabetes mellitus (NIDDM) and carcinoma. Elevated TNF-alpha initially increases, and then inhibits, the activity of a number of key enzymes involved in energy metabolism and major histocompatibility (MHC) class I molecule expression. These enzymes include: protein-tyrosine kinase (PTKase) and protein-tyrosine phosphatase (PTPase--enzymes involved in energy metabolism, cell proliferation and stimulation of the MHC class I molecule pathway. Of primary importance is the inhibiting effect of TNF-alpha on PTKase, since this induces insulin resistance in NIDDM and carcinoma, and PTPase, which inhibits MHC class I molecule expression. Studies have shown that IDDM is associated with an increase in PTPase activity which leads to overexpression of MHC class I molecules and a concomitant destruction of pancreatic beta cells. Conversely, carcinoma is associated with an inhibition of PTPase activity, which reduces the expression of MHC class I antigen expression on the cell surface thereby allowing malignant cells to escape immune surveillance. It will be argued that there is continuum of liability between these three conditions, initiated by the effect of TNF-alpha on these key enzymes.

Alterations of corticotropin releasing hormone (CRH) and neuropeptide Y (NPY) plasma levels in mood disorder patients with a recent suicide attempt

In order to receive a further understanding of stress-regulation in depressed suicide attempters, peptides that are supposed to be related to the stress system (the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system) were studied in plasma. When compared with healthy controls, cortisol was high (p<0.001) and corticotropin releasing hormone (CRH) and neuropeptide Y (NPY) appeared to be low (p<0.001) in patients who had recently attempted suicide. Patients who had repeatedly attempted suicide had the lowest NPY. A correlation between NPY and cortisol (p<0.05) was found in suicidal patients with depression NOS, whereas beta-endorphins correlated with cortisol (p<0.01) in suicidal patients with major depressive disorder. A postdexamethasone decrease of NPY was noted in the controls but not in the patients. These results suggest stress system alterations in suicidal patients with mood disorders.

An immunological model connecting the pathogenesis of stress, depression and carcinoma

Recently there has been considerable conjecture in the literature concerning a possible relationship between stress, depression and bereavement, and carcinoma. We shall propose a causal model in which the relationship between stress, depression and carcinoma is clarified. This relationship is grounded on dysregulation of the inflammatory cytokines in stress and depression. Stress is associated with increased expression of interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha), and reduced expression of IL-2, interferon-gamma (IFN-gamma), major histocompatability complex (MHC) class II molecules and natural killer cell activity (NKA). Depression is associated with elevated IFN-gamma and IL-1 beta, downregulated IL-2, and reduced NKA. Most organ-related carcinomas are associated with elevated TNF-alpha, which inhibits the activity of protein tyrosine phosphatase (PTPase), the enzyme that initiates activation of the MHC class I pathway. Sustained elevation of TNF-alpha inhibits the activity of PTPase which results in diminished expression of the MHC class I antigen on the cell surface and thus, malignant cells escape immune surveillance. Therefore, stress and depression can foster tumor progression by means of inhibiting the expression of MHC class I and II molecules and through the reduction of NKA.

Alzheimer caregiver stress: basal natural killer cell activity, pituitary-adrenal cortical function, and sympathetic tone

The association between Alzheimer caregiving and natural killer (NK) cell activity and basal plasma levels of adrenocorticotropic hormone (ACTH), cortisol, beta-endorphin, prolactin, epinephrine, norepinephrine, and neuropeptide Y was determined in 100 spousal Alzheimer caregivers and 33 age- and gender-comparable control volunteers upon intake into a study of the psychological and physiologic impact of caregiving. The relationship between these physiologic measures and individual characteristics such as age, gender, medical status, severity of stress, severity of depressive symptoms, and caregiver burden was tested. In addition, the association between NK activity and alterations of the neuroendocrine measures was investigated. As compared to controls, the Alzheimer caregivers had similar levels of NK activity and of basal plasma neuroendocrine hormones and sympathetic measures. While older age and male gender status were associated with increased levels of ACTH, neither medical caseness, severity of life stress, nor severity of depressive symptoms was associated with alterations in any of the multiple physiologic domains. Classification of Alzheimer caregiver burden identified caregivers who were mismatched in terms of the amount of care they were required to provide and the amount of respite time received. The mismatched caregivers had significantly higher basal plasma ACTH but no change in other physiological measures, as compared to non-mismatched caregivers. NK activity was negatively correlated with plasma levels of neuropeptide Y but not with any of the other neuroendocrine measures. Based on this cross-sectional evaluation of NK activity and neuroendocrine and sympathetic measures, we conclude that most Alzheimer caregivers do not show evidence of altered basal physiology.

Lymphocyte subsets associated with major depression and dysthymia: modification by antidepressant treatment

Major depression and dysthymia (chronic, low grade depression) were associated with an increase in the number of CD16/56 (natural killer; NK) cells in blood, whereas other lymphocyte subsets (CD3, CD4, CD8, CD19, and the CD4/CD8 ratio) did not differ from control subjects. After treatment with a specific serotonin reuptake inhibitor, the symptoms of depression were alleviated in both the major depressive and dysthymic patients. Likewise, NK cell numbers declined to control values in these treated groups. Among the major depressive patients, the NK cell number reached control values within 4 weeks, whereas 6 months of treatment was required for such an effect to be achieved in the dysthymic patients. Although plasma levels of epinephrine, norepinephrine, cortisol, and ACTH were not different between groups, among the major depressive patients ACTH was inversely correlated with total lymphocytes, CD3, and CD19, and epinephrine was directly related to the CD4 and CD4/CD8 ratio. Among dysthymics, ACTH was unrelated to any of the lymphocyte subsets, but norepinephrine was directly related to total lymphocytes, CD3, CD4, and NK cells. The data are interpreted in terms of stress perception among major depressive and dysthymic patients and the potential impact of stressor experiences on immune processes.

Viruses, neurosis and fatigue

The evidence for viral infections as a cause of anxiety, depression and fatigue is reviewed. It is argued that in order to fully understand any proposed relationship the effects of psychosocial factors on immunity, convalescence and illness behaviour must be acknowledged.