Hierarchical cortical control of neuroimmunomodulatory pathways

Visiting the cinema, concerts, museums or art exhibitions as determinant of survival: a Swedish fourteen-year cohort follow-up

The aim of this study was to ascertain the possible influence of attending various kinds of cultural events or visiting cultural institutions as a determinant of survival. A cohort of individuals aged 25-74 years from a random sample were interviewed by trained non-medical interviewers in 1982 and 1983. The interviews covered standard-of-living variables. Our independent variables covered visiting cultural institutions and attendance at cultural events, reading books or periodicals, and music making. The non-response rate was about 25%. The cohort was followed with respect to survival for 14 years up to 31st December 1996. The background covariates that were used for control purposes were age, sex, cash buffer, educational standard, long-term disease, smoking, and physical exercise. Our setting was the Swedish survey of living conditions among the adult Swedish population aged 25-74 years. About 10,609 individuals were interviewed in 1982 and 1983. The outcome measure was survival until 31st December 1996. In all, 916 men and 600 women died during this period. We found a higher mortality risk for those people who rarely visited the cinema, concerts, museums, or art exhibitions compared with those visiting them most often. The significant relative risks ranging between RR 1.14 (95% CI. 1.01-1.31) of attending art exhibitions, and RR 1.42 (CI. 1.25-1.60) of attending museums, when adjusting for the nine other variables. Visits to the cinema and concerts gave significant RR in between. We could not discern any beneficial effect of attending the theatre, church service or sports event as a spectator or any effect of reading or music making. Our conclusion is that attendance at certain kinds of cultural events may have a beneficial effect on longevity

The effects of Sceletium tortuosum in an in vivo model of psychological stress

AIM OF THE STUDY

Sceletium, and especially Sceletium tortuosum, is traditionally used as masticator and thought to have a sedative effect which may be beneficial to reduce symptoms of anxiety and/or depression. The current study evaluated the scientific merit of these anecdotal claims in an in vivo model of psychological stress.

MATERIALS AND METHODS

Male Wistar rats were administered either placebo, 5 or 20 mg/kg/day of Sceletium tortuosum extract for 17 days by daily oral gavage. 50% of rats were exposed to repeated restraint stress lasting 1h for the last 3 days of treatment. Rat behavioral changes in response to stress were assessed using the elevated plus maze on the last day of restraint, immediately after the restraint session. Rats were sacrificed 24h after the last restraint exposure and whole blood collected.

RESULTS

Behavior indicated a limited effect of lower dose Sceletium to decrease restraint stress-induced self-soothing behavior, as well as to decrease stress-induced corticosterone levels. However, increased IL-1β levels argue against the claim that the plant may act as selective serotonin reuptake inhibitor, while this result combined with increased levels of C-reactive protein and prostaglandin E(2) suggest intolerance to the treatment. Decreased IL-2 and increased IL-10 levels in response to Sceletium treatment suggest a suppressive effect on T helper 1 immune function.

CONCLUSIONS

Although data indicates a limited positive effect of Sceletium on restraint-induced anxiety, numerous side-effects were evident. More research is required to derive an optimal therapeutic dose.

Sensory circumventricular organs in health and disease

Circumventricular organs (CVOs) are specialized brain structures located around the third and fourth ventricles. They differ from the rest of the brain parenchyma in that they are highly vascularised areas that lack a blood-brain barrier. These neurohaemal organs are classified as "sensory", when they contain neurons that can receive chemical inputs from the bloodstream. This review focuses on the sensory CVOs to describe their unique structure, and their functional roles in the maintenance of body fluid homeostasis and cardiovascular regulation, and in the generation of central acute immune and febrile responses. In doing so, the main neural connections to visceral regulatory centres such as the hypothalamus, the medulla oblongata and the endocrine hypothalamic-pituitary axis, as well as some of the relevant chemical substances involved, are described. The CVOs are vulnerable to circulating pathogens and can be portals for their entry in the brain. This review highlights recent investigations that show that the CVOs and related structures are involved in pathological conditions such as sepsis, stress, trypanosomiasis, autoimmune encephalitis, systemic amyloidosis and prion infections, while detailed information on their role in other neurodegenerative diseases such as Alzheimer's disease or multiple sclerosis is lacking. It is concluded that studies of the CVOs and related structures may help in the early diagnosis and treatment of such disorders.

Mechanisms of brain signaling during sepsis

Brain signaling is a crucial event for the body to mount an appropriate response to invading microorganisms. Pro-inflammatory cytokines are released from infected tissues and reach key structures in the brain via the circumventricular organs, areas of damaged blood brain barrier or they cross actively the blood brain barrier using specific carriers. Alternately, cytokines may activate brain endothelial cells or microglial to produce prostaglandins which then diffuse into the brain to activate neurons. Finally, cytokines may activate the autonomic nervous system at the periphery. The following crosstalk between astrocytes and microglial precedes neuronal activation particularly within the hippocampus, amygdale and hypothalamus. The resulting release of neuro-hormones in the systemic circulation allows restoration of homeostasis. It is likely that an excess in nitric oxide and complement anaphylatoxin C5a contributes to DNA damage within neurons of the hippocampus and hypothalamus and subsequent brain dysfunction.

Overtraining, excessive exercise, and altered immunity: is this a T helper-1 versus T helper-2 lymphocyte response?

Overtraining syndrome (OTS) occurs where an athlete is training vigorously, yet performance deteriorates. One sign of OTS is suppressed immune function, with an increased incidence of upper respiratory tract infection (URTI). An increased incidence of URTIs is also associated with high volume/intensity training, as well as with excessive exercise (EE), such as a marathon, manifesting between 3-72 hours post-race. Presently, there is no encompassing theory to explain EE and altered immune competence. Recently, it has been conclusively established that T helper lymphocytes (T(H)), a crucial aspect of immune function, represent two distinct functional subsets: T(H)1 and T(H)2 lymphocytes. T(H)1 lymphocytes are associated with cell-mediated immunity (CMI) and the killing of intracellular pathogens, while T(H)2 lymphocytes are associated with humoral immunity and antibody production. When T(H)-precursor cells are activated, the balance is tipped in favour of one or the other. Furthermore, the most appropriate means of determining the T(H)-subset, is by the prevailing cytokine 'pattern'. This paper hypothesises that exercise-related immunosuppression is due to tissue trauma sustained during intense exercise, producing cytokines, which drive the development of a T(H)2 lymphocyte profile. A T(H)2 cell response results in simultaneous suppression of CMI, rendering the athlete susceptible to infection. Additionally, increased levels of circulating stress hormones (cortisol and catecholamines), as well as prostaglandin E(2), support up-regulation of T(H)2 lymphocytes. Marathon-related data are presented to support this hypothesis. It is concluded that an increased incidence of illness associated with OTS and in response to EE is not due to immunosuppression per se, but rather to an altered focus of immune function, with an up-regulation of humoral immunity and suppression of CMI.

Leisure time activity as a determinant of survival: a 26-year follow-up of a Swedish cohort

An individual's leisure time (pastime) engagements are in a way important for society. Irrespective of whether leisure time activities are causal determinants of health or health is a prerequisite for taking full part in society, the interaction is a challenge for Public Health. The first question is whether the sum of their influence results in coherence between enjoying good health and having leisure time activity. The aim of this study was to estimate their covariance.A random sample was drawn from the adult population of Stockholm County, Sweden. The residents were mailed a questionnaire regarding their social circumstances, their health complaints, the social repercussions of the complaints, and if they had any leisure time activity. Altogether, 7252 (about 93%) individuals responding to the questionnaire constituted our cohort. The individuals aged 18-65 y in November 1969 were followed up to the age of 65 y, or to 1996 as to mortality. The main outcome measure was mortality irrespective of cause of death. More than two-thirds of the respondents (71%) reported that they had some leisure time activity. Leisure time activity was a determinant of survival in the statistical sense. The risk ratio was 0.77 and its 95% confidence interval was 0.68-0.87 for those reporting leisure time activity when age, sex, baseline health and baseline alcohol consumption was discounted. The conclusion was that having leisure time activity, unspecified, covaried with health. Further studies should specify the pastime activities.

Brain IL-1beta increases neutrophil and decreases lymphocyte counts through stimulation of neuroimmune pathways

Leukocytosis after cerebral injury is well described and may participate in the generation of cerebral damage. However, the mechanisms of brain-induced leukocytosis are still speculative. Since it is known that proinflammatory cytokines are involved in neuroimmunomodulation and since others and we have demonstrated high cytokine levels in the cerebrospinal fluid following injury, we supposed that brain cytokines may also influence leukocyte counts. In order to evaluate this hypothesis, we established an animal model using continuous intracerebroventricular (i.c.v.), intrahypothalamic (i.h.), or intravenous infusion of the proinflammatory cytokines tumor necrosis factor (TNF)-alpha and IL-1beta. Controls received vehicle solution. With this experimental paradigm we could show that i.c.v. and i.h. infusion of IL-1beta but not TNF-alpha dramatically increased neutrophil counts, whereas lymphocytes dropped. Blocking the hypothalamic-pituitary-adrenal (HPA) axis by hypophysectomy abolished the neutrophilia, whereas the lymphopenia remained unchanged. Furthermore, application of the beta2-adrenoreceptor antagonist propranolol prevented the decrease of lymphocytes and diminished the neutrophilia. All parameters normalized within 48 h after termination of infusion. So, our results demonstrate that brain IL-1beta can modify blood leukocyte counts through stimulation of both the sympathetic nervous system (SNS) and the HPA axis.