Serum profile of melatonin, cytokines and cortisol in pregnant women with preeclampsia

Author(s)

Eugenia Maria Assunção Salustiano

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2014-07-02

Examining board members

Rodrigo Ruano; Geraldo Duarte; Rossana Pulcineli Vieira Francisco; Soubhi Kahhale; José Carlos Peraçoli

• Advisor: Rodrigo Ruano

Abstract

Preeclampsia (PE) is a major cause of maternal and perinatal mortality and morbidity. Since its etiology remains unknown, it is impossible to have a primary prevention of the disease. The understanding of the substance profiles that are altered in PE is important to prevent the disease. Considering that many hormones involved in immune response are involved in the physiopathology of PE and that melatonin has a relevant role in the acute inflammatory process, our hypothesis is that this hormone would also be involved in the physiopathology of PE. OBJECTIVES: To analyze the serum profile of cytokines and hormones in pregnant women with PE in order to evaluate if the immune-pineal axis is activated in this disease. METHODS: A prospective case-control study was conducted at the Clinical Hospital USP between October 2010 and October 2013. Only patients with pure PE at the moment of diagnosis (without anti-hypertensive medication for the initial 24h after diagnosis) were included. Normotensive healthy pregnant women that were matched by maternal age, gestational age and parity were included as controls. Cytokines (IL-6, IL-1b, IL-8, TNF and IFNy), cortisol and serum melatonin levels in the morning (08h-11h) and at night (23h-01h), as well as 6-sulfatoximelatonin (6-SMT) levels in different periods of the day (bl1:12h- 18h, bl2:18h-24h, bl3:24h-06h, bl4:06-12h) were measured by MULTIPLEX and ELISA. Differences between groups were analyzed using two-way ANOVA followed by Bonferronis\'s test. Statistical difference was considered when the null hypothesis was rejected (p < 0.05). Correlations between parameters were analyzed using linear regression and Pearson test. RESULTS: From a total of 31 patients initially evaluated, 14 patients with PE and 12 controls were included. Demographics such as maternal age, parity, gestational age at the dosages, body-mass index were similar in both groups (p > 0.05). TNF and IL-8 levels were higher in the preeclampsia group than controls, while IL-6, IL-1beta, VEGF, IL-10, IL-17 and IL-12p40 were not detected in both groups. IL-4 levels were similar in both groups. There was a tendency of higher levels of IFNy, in patients with PE when compared to controls. Our analysis revealed a positive correlation between melatonin and TNF, melatonin and IL-8, TNF and IL-8 in PE group. Daytime cortisol levels were higher in both groups when compared to nighttime; however, patients with preeclampsia had reduced morning levels of cortisol when compared to the control group. Melatonin serum level was higher at daytime, but not at nighttime, in patients with PE when compared to controls. Controls had the expected day/nighttime rhythm of the melatonin levels, while patients with PE did not have it. In contrast, 6-SMT rhythm was observed in both groups, but with higher daytime levels in patients with PE when compared to controls. CONCLUSION: Our results suggest that PE alters negatively the hypothalamic-pituitary-adrenal axis, but induces an increase in TNF, which signalizes an acute inflammatory response. Furthermore, it is believed that high levels of IL-8 and TNF can configure a feedback system that contributes to the development of the disease and immune pineal axis activation. Therefore, this effect may be associated with increased daytime melatonin levels in PE, induced by TNF in immunocompetent cells. Thus, our data suggest that the increased melatonin and 6-SMT in patients with PE may be originated from an extra-pineal axis (AU)

• FAPESP's process: 12/07762-0 - Serum profile of melatonin, cytokines and cortisol in pregnant women with preeclampsia
• Grantee: Eugênia Maria Assunção Salustiano
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)