# Sex differences in human umbilical vein endothelial cells following ox-LDL injury

## TL;DR

This study found that male and female fetal cells respond differently to cholesterol-related damage, with female cells showing better resilience and repair.

## Contribution

The study reveals sex-specific differences in endothelial cell responses to ox-LDL-induced stress in fetal life.

## Key findings

- Male HUVECs showed increased apoptosis and mitochondrial damage compared to female HUVECs.
- Female HUVECs exhibited enhanced autophagy and repair mechanisms, protecting against cell death.
- Sex differences in oxidative stress and inflammation suggest early-life origins of cardiovascular risk.

## Abstract

Numerous sex differences has been described in aterosclerosis including in endothelial dysfunction. Oxidized low-density lipoproteins (ox-LDL) contribute to the formation of atherosclerotic plaque by binding to a membrane glycoprotein expressed by endothelial cells. Ox-LDL also play a key role in mediating endothelial dysfunction during pregnancy. Elevated maternal ox-LDL levels can lead to oxidative stress, inflammation and apoptosis in placental and fetal endothelial cells. The aim of this study was to investigate sex-related differences in the response to ox-LDL-induced damage in human umbilical vein endothelial cells (HUVECs) isolated from male and female newborns.

In our study, the effects of 100 µg/ml ox-LDL on HUVECs, obtained from umbilical cords of healthy newborns of both sexes, were analyzed. By flow cytometry, fluorescence microscopy, and Western blotting techniques, mitochondrial function, cell survival, and autophagy were studied.

Sex differences in cell motility and fate have been detected after ox-LDL treatment. Indeed, following ox-LDL treatment, male HUVECs (MHUVECs) exhibited reduced motility and a significant increase in adhesion molecules ICAM-1 and VCAM-1, in contrast to female HUVECs (FHUVECs). Furthermore, MHUVECs exhibited higher levels of fission proteins (DRP1 and Fis1), superoxide anion (O₂⁻), and earlier mitochondrial membrane (MM) hyperpolarization, while FHUVECs showed higher levels of fusion proteins (OPA1 and MFN2), hydrogen peroxide (H₂O₂), and delayed MM changes. These findings were consistent with a greater propensity for apoptosis in MHUVECs. In contrast, FHUVECs exhibited higher levels of Survivin, making them less susceptible to apoptosis and more susceptible to the autophagy process.

Our findings reveal significant sex-related variations in endothelial responses to oxidative stress. The enhanced survival and repair capacity of FHUVECs suggests that female cells are more resilient to ox-LDL-induced damage.

The online version contains supplementary material available at 10.1186/s13293-026-00845-5.

Atherosclerosis, a major cause of cardiovascular disease, is a condition in which arteries become obstructed by fatty deposits, which often begin with damage to endothelial cells that line blood vessels. One of the main causes of this condition is oxidized low-density lipoproteins (ox-LDL), harmful form of cholesterol that triggers inflammation, oxidative stress and cell death. These processes can contribute to the development and progression of atherosclerotic plaque. This study investigated the effects of ox-LDL on human umbilical vein endothelial cells (HUVECs) from healthy male and female newborns. The data showed that ox-LDL reduce cell movement and increase oxidative stress in both sexes, but male cells were more vulnerable than female cells. Male cells exhibited higher levels of reactive oxygen species, exhibited earlier and more severe mitochondrial damage, and underwent greater apoptotic cell death. They also exhibited higher levels of proteins associated with inflammation and impaired cell repair. In contrast, female cells were better at adapting to the stress caused by ox-LDL. They maintained healthier mitochondria, exhibited stronger repair responses and activated protective processes such as autophagy, which helps to remove damaged components. These sex-related differences suggest that male and female fetuses may respond differently to cholesterol-related damage even before birth. This could influence their future risk of cardiovascular disease. Understanding these differences could inform the development of more personalized approaches to preventing heart disease from early life onwards. This could also provide potential biomarkers and/or innovative preventive approaches to combat the onset of cardiovascular disease from the womb onwards, ensuring personalized care.

The online version contains supplementary material available at 10.1186/s13293-026-00845-5.

This study examined how male and female human umbilical vein endothelial cells (MHUVECs, FHUVECs) responded differently to ox-LDL-induced damage.Ox-LDL reduced cell motility and increased oxidative stress and apoptosis, particularly in male cells.MHUVECs showed higher levels of inflammatory markers (ICAM-1, VCAM-1), mitochondrial damage, and cell death pathways (Caspase-3, Bax).FHUVECs exhibited better repair capacity, increased mitochondrial fusion, and higher Survivin expression, which protects against apoptosis.Reactive oxygen species production and mitochondrial membrane changes occurred earlier and more severely in male cells.Only male cells showed impaired autophagy, with increased p62 accumulation, while female cells maintained functional autophagy.The data obtained suggest sex-dependent cellular responses to cholesterol-induced stress begin in fetal life and may influence future cardiovascular risk.

This study examined how male and female human umbilical vein endothelial cells (MHUVECs, FHUVECs) responded differently to ox-LDL-induced damage.

Ox-LDL reduced cell motility and increased oxidative stress and apoptosis, particularly in male cells.

MHUVECs showed higher levels of inflammatory markers (ICAM-1, VCAM-1), mitochondrial damage, and cell death pathways (Caspase-3, Bax).

FHUVECs exhibited better repair capacity, increased mitochondrial fusion, and higher Survivin expression, which protects against apoptosis.

Reactive oxygen species production and mitochondrial membrane changes occurred earlier and more severely in male cells.

Only male cells showed impaired autophagy, with increased p62 accumulation, while female cells maintained functional autophagy.

The data obtained suggest sex-dependent cellular responses to cholesterol-induced stress begin in fetal life and may influence future cardiovascular risk.

The online version contains supplementary material available at 10.1186/s13293-026-00845-5.