# Gender-Specific Gene Regulation of Ferroptosis in Non-Utilized Liver Donors

## TL;DR

This study explores how sex influences gene regulation of ferroptosis in non-used donor livers, finding no major sex-based differences in most genes, except for a potential trend in one gene in female livers.

## Contribution

The study is the first to systematically investigate sex-based differences in ferroptosis gene regulation in non-utilized human donor livers using ex vivo normothermic machine perfusion.

## Key findings

- Normothermic machine perfusion of non-utilized donor livers was feasible.
- No significant sex-based differences were found in MDA levels or most ferroptosis-related gene expression after 6 hours.
- ACSF2 expression was higher in female livers, but not significant after multiple testing correction.

## Abstract

Background/Objectives: Females are generally more resistant to ischemia-related ferroptosis than males, due to differences in iron metabolism, antioxidant pathways, and sex hormone-mediated regulation of ferroptosis suppressors. This has not been systematically studied in a human donor liver model. To investigate the effect of sex on ferroptosis and oxidative stress pathways in non-utilized donor livers (NDLs), we assessed patterns of gene expression in NDLs under ex vivo normothermic machine perfusion (NMP). Methods: We utilized the PROTECT dual-circuit ex vivo NMP system to assess three male and two female NDLs undergoing 6 h NMP. Perfusate and tissue samples were collected at baseline and 6 h of NMP. Malondialdehyde (MDA) levels were quantified as biochemical markers of iron overload and lipid peroxidation, respectively. Ferroptosis-related gene expression was assessed using molecular assays. Comparisons between male and female NDLs were used to determine the influence of sex on ferroptosis and oxidative injury during NMP. Results: NMP was successfully performed on NDLs (n = 5) from three male (56.3 ± 5.7 years) and two female donors (46.5 ± 0.7 years, p = 0.15). The fold-change in the oxidative stress marker MDA was comparable between female (1.2 ± 0.6) and male (1.0 ± 0.4) NDLs after 6 h NMP (p = 0.76). All livers showed upregulation of ferroptosis-related genes (Hypoxia-inducible factor 1 alpha, Iron Responsive Binding Elements 2, Ribosomal Protein L8, Ferritin Heavy Chain 1, Acyl-CoA synthetase family member 2, ATP synthase membrane subunit c locus 3, Heme-oxygenase 1, NAD(P)H Quinone Dehydrogenase 1, Tetratricopeptide Repeat Domain 35, Nuclear Factor Erythroid 2 Related Factor 2). ACSF2 expression was significantly higher in female NDLs compared with males undergoing 6 h NMP (3.6 ± 3.0 vs. 1.0 ± 0.7-fold change, p = 0.04). There were no sex-based significant differences observed in the expression of other ferroptosis-related genes (HIF-1α, IREB2, RPL8, FTH-1, ATP5G3, HO-1, NQO1, TTC35, and NRF2) between male and female NDLs. No gene reached statistical significance after false-discovery-rate (FDR) correction. Conclusions: Normothermic machine perfusion of NDLs was feasible, and no sex-related differences were observed in MDA levels or most ferroptosis-related gene expression after 6 h. Although ACSF2 showed higher expression in female livers, this was not significant after multiple testing correction, highlighting the need for larger studies to explore sex-dependent ferroptosis signaling during liver preservation.