Mitochondrial energetics and contents evaluated by flow cytometry in human maternal and umbilical cord blood

Abstract

Background: Mitochondrial dysfunction may relate to metabolic disorders. The relation between maternal and fetal mitochondrial function needs attention due to heritage.

Objectives: To evaluate the use of the staining methods TetraMethylRhodamine Methyl Ester (TMRM) and Mitotracker Green (MTG) for flow cytometric measurements of umbilical cord blood mitochondrial function.

Methods: 53 euthyroid at-term pregnant women and their offspring were included by blood collections. The offspring had blood drawn from the clamped umbilical cord. Flow cytometry with MTG, TMRM and Propidium Iodide were performed the following day. A cell count (antibody coating and flow cytometry) was performed for 9 maternal and cord samples. As a quality control, blood of 32 healthy donors was evaluated by flow cytometric analyzes same day as sampling and the following day to test stability of the measurements.

Results: Cord mitochondrial measurements were lower than maternal. Maternal and cord mitochondrial function were positively correlated, especially reflected by MTG fluorescence-intensity (FI). Samples stored presented with very changed fluorescence patterns. However, the fluorescence intensity ratios MTG/TMRM of stained white blood cells were related within same day measurements, depicting an extensive and common bioenergetic cellular change.

Conclusion: Cord blood flow cytometry by MTG- and TMRM- staining is possible with fluorescence intensity positively correlated to maternal fluorescence intensity. Storage of blood triggers mitochondrial dynamics. The methods are applicable with certain reservations, and they benefit from their non-invasive character compared to mitochondrial evaluation by muscle-biopsies.

Keywords:

• Fetal blood
• pregnancy
• flow cytometry
• membrane potential
• mitochondrial
• mitochondria
• cell death

Acknowledgements

The authors thank technicians Jette Ellehauge and Carina Foldager at the Department of Clinical Biochemistry at Naestved Hospital, Region Zealand, Denmark, for their dedicated and skilled work. Moreover, we would like to thank professor MD Jan Kvetny for inspiration and launching of the project.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by grants from Error! Hyperlink reference not valid., the Medical Research Foundation of Naestved, Slagelse and Ringsted Hospitals, Region Zealand and the Department of Gynecology and Obstetrics, Naestved Hospital.