A new study proposes that metformin’s benefits in gestational diabetes extend beyond glucose control, potentially safeguarding placental health by inhibiting ferroptosis through the ATF2-PI3K/Akt-Nrf2-GPX4 pathway.
A study published in The FASEB Journal reports that metformin may do more in gestational diabetes than lower glucose alone, easing placental injury by suppressing the transcription factor ATF2 and restoring an antioxidant defence pathway linked to ferroptosis, an iron-driven form of cell death. The work combines placental samples from women with gestational diabetes, experiments in HTR-8/SVneo trophoblast cells and a streptozotocin-induced rat model, and it builds on the authors’ earlier finding that ATF2 is elevated in gestational diabetes and appears to worsen trophoblast damage.
In the patient data, the researchers said placental ATF2 was more highly expressed in gestational diabetes than in comparison groups, while metformin-treated cases tended to show lower ATF2 and higher GPX4, a protein that helps prevent ferroptosis. The same cohort also showed lower neonatal birth weight and glycated haemoglobin in the metformin group than in insulin-treated or poorly controlled cases, alongside lower ferritin and transferrin, suggesting a possible link between treatment and improved iron balance, according to the report.
The laboratory findings pointed in the same direction. Under high glucose, trophoblasts showed weaker viability, more oxidative stress and more iron accumulation, while metformin improved cell survival, reduced lipid peroxidation markers and increased glutathione. When ATF2 was overexpressed, those benefits were partly lost, and the ferroptosis inducer erastin reversed them further, reinforcing the idea that ATF2 sits upstream of the damage pathway.
Mechanistically, the study says metformin helped reactivate PI3K and Akt, two proteins in a well-known survival pathway, and that this in turn supported Nrf2 movement into the nucleus. Once there, Nrf2 can switch on genes that defend against oxidative injury, including GPX4. Blocking PI3K with LY294002 or Nrf2 with ML385 weakened metformin’s protective effects, which the authors interpret as evidence that the drug’s anti-ferroptotic action depends on the ATF2-PI3K/Akt-Nrf2-GPX4 axis.
The rat experiments backed up the cell work. In the streptozotocin model, metformin improved glucose tolerance, lowered placental ATF2, restored GPX4, reduced reactive oxygen species and malondialdehyde, and increased glutathione. The treatment also promoted Nrf2 nuclear entry, while ATF2 overexpression blunted these changes. The authors caution, however, that the doses used in the animal and cell experiments were higher than typical clinical exposure, the HTR-8/SVneo line is only a partial model of trophoblast biology, and the streptozotocin system does not fully reproduce human gestational diabetes.
Taken together, the study argues that metformin may protect the placenta in gestational diabetes by interrupting an ATF2-driven chain of events that links high glucose to iron overload, lipid peroxidation and ferroptosis. That framing broadens the usual view of metformin as a glucose-lowering drug and points to a potential placental mechanism that could matter for maternal and fetal outcomes. The authors say larger, more clinically realistic studies will be needed before the pathway can be translated into routine care.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
