Association between low levels of anti-inflammatory cytokines during pregnancy and postpartum depression.

AIM: Previous studies based on a relatively limited number of subjects have indicated potential associations between plasma cytokine concentrations in perinatal women and postpartum depression (PPD). This report aimed to examine alterations in cytokine levels during pregnancy and after delivery by measuring nine cytokines in prenatal and postnatal plasma samples in a large cohort. METHODS: A nested, case-control study was conducted using plasma samples from 247 women with PPD (Edinburgh Postnatal Depression Scale: EPDS ≥9) and 243 age-matched control (EPDS ≤2) women from among perinatal women who participated in the Tohoku Medical Megabank three-generation cohort. Concentrations of nine plasma cytokines (IFN-γ, IL-1ß, IL-4, IL-6, IL-10, IL-12p40, IL-12p70, IL-13, and TNF-α) in plasma collected at the time of enrollment during pregnancy and 1 month after delivery were determined using an immunoassay kit. RESULTS: Cross-sectional comparisons of cytokine levels during pregnancy and after delivery indicated that the PPD group maintained significantly lower plasma IL-4 levels during pregnancy and after delivery than the control group, and that plasma IL-4 levels decreased significantly during pregnancy regardless of PPD status. Plasma IL-10 levels were significantly higher during pregnancy than after delivery only among healthy controls, and plasma IL-10 levels were significantly higher in the control group than in the PPD group. Moreover, IFN-γ, IL-6, IL-12p40, and TNF-α levels were significantly lower during pregnancy compared with after delivery regardless of PPD status. CONCLUSIONS: These results suggest a potential protective effect of the anti-inflammatory cytokines IL-4 and IL-10 during pregnancy against the development of PPD.

Minimal amount of tissue-based pH measurement to improve quality control in neuropsychiatric post-mortem brain studies.

AIM: Tissue pH and RNA integrity are crucial quality-control indicators of human post-mortem brain tissues in the identification of the pathogeneses of neuropsychiatric disorders, but pH has not been measured as often due to limitations in the amount of tissue available. This study was designed to develop and validate a protocol for tissue pH evaluation using a minimal amount of human post-mortem tissues. METHODS: A procedure that included a proper ratio of brain tissue weight to water for homogenization and the duration of homogenization was designed based on preliminary experiments using mouse brain tissues. The minimal (10 mg) and typical (100 mg) amounts of post-mortem brain tissue from 52 subjects were homogenized in 5 volumes (50 µL/10 mg tissue) and 10 volumes (1000 µL/100 mg tissue) of nuclease-free water and subjected to pH measurements using an InLab Ultra micro pH electrode. RESULTS: The pH values based on the new protocol using a minimal amount of tissue significantly correlated with measurements of the standard protocol (r2 = 0.86). The correlation coefficients of the pH values between gray and white matter of the same brain region, and the values between different brain regions were 0.73 and 0.54, respectively. CONCLUSION: The proposed protocol used one-tenth of the tissue amount of current standard protocol and enabled us to evaluate the exact quality of post-mortem brain tissue subjected to subsequent analyses. The application of this protocol may improve the detection of biological phenomena of interest in post-mortem brain studies by diminishing confounding factors.