Mitochondrial content and hepcidin are increased in obese pregnant mothers

Abstract

Objective: Maternal obesity is characterized by systemic low-grade inflammation and oxidative stress (OxS) with the contribution of fetal sex dimorphism. We recently described increased mitochondrial content (mtDNA) in placentas of obese pregnancies. Here, we quantify mtDNA and hepcidin as indexes of OxS and systemic inflammation in the obese maternal circulation.

Methods: Forty-one pregnant women were enrolled at elective cesarean section: 16 were normal weight (NW) and 25 were obese (OB). Obese women were further classified according to the presence/absence of maternal gestational diabetes mellitus (GDM); [OB/GDM(–)]: n = 15, [OB/GDM(+)]: n = 10. mtDNA and hepcidin were evaluated in blood (real-time PCR) and plasma (ELISA).

Results: mtDNA and hepcidin levels were significantly increased in OB/GDM(–) versus NW, significantly correlating with pregestational BMI. Male/female (M/F) ratio was equal in study groups, and overall F-carrying pregnancies showed significantly higher mtDNA and hepcidin levels than M-carrying pregnancies both in obese and normal weight mothers.

Conclusions: Our results indicate a potential compensatory mechanism to increased obesity-related OxS and inflammation, indicated by the higher hepcidin levels found in obese mothers. Increased placental mitochondrial biogenesis, due to lipotoxic environment, may account for the greater mtDNA amount released in maternal circulation. This increase is namely related to F-carrying pregnancies, suggesting a gender-specific placental response.

Keywords:

• Gestational diabetes mellitus
• hepcidin
• maternal obesity
• mitochondrial DNA
• sexual dimorphism

Acknowledgements

We thank midwives and nurses of the Unit of Obstetrics and Gynecology, Sacco Hospital (Milan), for their competence and cooperation. We also thank all pregnant patients for participating in the study.

This paper has benefited from technical support and scientific enthusiasm of Francesca Nardi.

This work was financially supported by a donation from Fondazione Giorgio Pardi and by the grant of MIUR codified as ‘PRIN 2010-2011-prot. 20102chst5_005’ and entitled as “Parto pre-termine: markers molecolari, biochimici e biofisici dell’unita feto-placentare” (to I.C.).

Disclosure statement

The authors report no conflict of interest.

Additional information

Funding

This work was financially supported by a donation from Fondazione Giorgio Pardi and by the grant of MIUR codified as ‘PRIN 2010-2011-prot. 20102chst5_005’ and entitled as “Parto pre-termine: markers molecolari, biochimici e biofisici dell’unita feto-placentare” (to I.C.).