PT46 - ALTERED MITOCHONDRIAL MORPHOLOGY AND MFN1 EXPRESSION IN PLACENTAS FROM ADVANCED MATERNAL AGE PREGNANCIES

PT46

ALTERED MITOCHONDRIAL MORPHOLOGY AND MFN1 EXPRESSION IN PLACENTAS FROM ADVANCED MATERNAL AGE PREGNANCIES

J. Moreno-Fernandez^1,2,3,4,*, M. Puche-Juarez^1,2,3, J. M. Toledano^1,2,3, J. J. Ochoa^1,2,3,4, L. Manzanares-Rios¹, C. De Paco-Matallana^5,6, M. P. Carrillo⁷, E. Martín-Álvarez⁸, J. Diaz-Castro^1,2,3,4

¹Physiology, University of Granada, ²Institute of Nutrition and Food Technology, ³Biomedical Research Centre, ⁴Instituto de Investigación Biosanitaria (IBS), Granada, ⁵Department of Obstetrics and Gynecology, Virgen de la Arrixaca' University Hospital, ⁶Institute for Biomedical Research of Murcia, Murcia, ⁷Department of Obstetrics & Gynaecology, ⁸Unit of Neonatology, Pediatric Service, Virgen de las Nieves University Hospital, Granada, Spain

Rationale: Advanced maternal age (AMA), defined as ≥35 years at delivery, is associated with increased risk of obstetric and perinatal complications, often due to impaired placental function. Mitochondria are essential for placental homeostasis and development, and Age-related changes in mitochondrial dynamics may be the cause of dysfunctions observed in AMA pregnancies. This study aimed to evaluate placental mitochondria in AMA pregnancies, focusing on morphological alterations and fusion-related protein expression.

Methods: Placentas from women ≥35 years (n=10) and <35 years (n=9) were collected at delivery from “Virgen de las Nieves” (Granada) and “Virgen de la Arrixaca” (Murcia) hospitals. Tissue samples from the subchorial zone were fixed in 2% glutaraldehyde + 1% formaldehyde and processed for transmission electron microscopy (TEM). Morphological analysis was performed using ImageJ to assess mitochondrial area and quantity. Protein extraction was carried out from another tissue fraction using RIPA buffer with protease inhibitors. Western blot analysis was used to evaluate the expression of mitochondrial fusion proteins MFN1 and MFN2. The protein signal was quantified with Image Lab software. Statistical analysis was performed using GraphPad Prism 9.

Results: AMA placentas showed significantly decreased mitochondrial area and increased quantity in both the cytotrophoblast and syncytiotrophoblast (P<0.05). MFN1 expression was significantly lower in AMA samples (P<0.001), while MFN2 expression showed no significant difference.

Conclusion: Mitochondria in AMA placentas exhibit morphological changes, with decreased size but increased content, suggesting excessive fragmentation and potential dysfunction. Reduced MFN1 expression may be linked to these alterations, indicating impaired mitochondrial fusion, which could contribute to placental insufficiency and adverse perinatal outcomes in AMA pregnancies.

Disclosure of Interest: None declared