Tumor necrosis factor-alpha and mood disorders in the elderly

Associations of depression with C-reactive protein, IL-1, and IL-6: a meta-analysis

OBJECTIVE

To assess the magnitude and direction of associations of depression with C-reactive protein (CRP), interleukin (IL)-1, and IL-6 in community and clinical samples.

METHODS

Systematic review of articles published between January 1967 and January 2008 in the PubMed and PsycINFO electronic databases was performed. Effect sizes were calculated as stat d and meta-analyzed, using random-effects models.

RESULTS

Each inflammatory marker was positively associated with depression; CRP, d = 0.15 (95% CI = 0.10, 0.21), p < .001; IL-6, d = 0.25 (95% CI = 0.18, 0.31), p < .001; IL-1, d = 0.35 (95% CI = 0.03, 0.67), p = .03; IL-1ra, d = 0.25 (95% CI = 0.04, 0.46), p = .02. Associations were strongest in clinically depressed patient samples--but were also significant in community-based samples--and when clinical interviews were used. Studies adjusting for body mass index (BMI) had smaller associations, albeit significant. Relationships were inconsistent with respect to age, medication, and sex. Depression was related to CRP and IL-6 among patients with cardiac disease or cancer.

CONCLUSIONS

Depression and CRP, IL-1, and IL-6 are positively associated in clinical and community samples and BMI is implicated as a mediating/moderating factor. Continuity in clinic- and community-based samples suggests there is a dose-response relationship between depression and these inflammatory markers, lending strength to the contention that the cardiac (or cancer) risk conferred by depression is not exclusive to patient populations. Available evidence is consistent with three causal pathways: depression to inflammation, inflammation to depression, and bidirectional relationships.

Healthy aging is associated with unaltered production of immunoreactive growth hormone but impaired neuroimmunomodulation

BACKGROUND

Both endocrine and immune systems are continuously remodeled during aging.

OBJECTIVE

Here, we investigated to what extent adrenal and somatosenescence are associated reciprocal changes in the immune system during strictly healthy aging.

METHODS

Forty-six elderly subjects and 33 young adults were recruited according to the health criteria of the SENIEUR protocol. Peripheral blood mononuclear cells were isolated and stimulated in vitro with lipopolysaccharide or phytohemagglutinin to assess the production of immunoreactive growth hormone (GH). Peripheral sensitivity to steroids was assessed in vitro by dexamethasone-, cortisol- or dehydroepiandrosterone (DHEA)-induced inhibition of T-cell proliferation. DHEA and GH levels were measured by radioimmunoassays.

RESULTS

Healthy elderly had lower salivary DHEA and serum GH levels (somatosenescence). They presented reduced T-cell sensitivity to dexamethasone but similar cellular sensitivities to cortisol and DHEA. Their cells produced similar levels of immunoreactive GH compared to the cells of young adults.

CONCLUSIONS

These data indicate that healthy aging is associated with adrenal and somatosenescence as well as impaired neuroendocrine immunoregulation at the level of the lymphocyte. In addition, somatosenescence may not be associated with a reciprocal decline in immunoreactive GH.