“The present study has contributed evidence in support of the role of oxidative stress in mood disorders and is the first study to our knowledge that examined GSH in women at risk for suicide,” they wrote in the journal Frontiers in Psychiatry.
The research, led by the Universidade Católica de Pelotas, was supported by Brazil’s National Council for Scientific and Technological Development (CNPq) in collaboration with the Bill & Melinda Gates Foundation.
Glutathione and the vulnerable brain
The researchers pointed to increasing global suicide rates and cited data from a 2022 study estimating the suicide mortality rate in Brazil at about 5.5 deaths per 100,000 inhabitants, with close to 10,000 suicide deaths a year (and the vast majority linked to depression).
In the study population, the researchers noted: “While the risk of death and suicide attempts is lower during and shortly after pregnancy than in the general female population, suicides account for up to 20% of all postpartum deaths and represent a leading cause of mortality in the peripartum period, which corroborates the high prevalence of suicide risk in our sample of women.”
Based on growing evidence linking oxidative damage with neurodegenerative changes associated psychiatric disorders, as well as the intrinsic oxidative vulnerability of the brain, the study set out to evaluate the serum levels of oxidative stress biomarkers in women at risk of suicide after 18 months of postpartum.
“Glutathione is the brain’s main antioxidant, and recent post-mortem and genetic data support its involvement in the pathophysiology of bipolar disorder,” the researchers added. “Glutathione reduced (GSH) is therefore a sensitive and reliable endogenous marker of oxidative stress.”
The case-control study, nested within a cohort study, evaluated 45 women at 18 months postpartum: 15 without mood disorders and 30 with mood disorders characterized by major depression and bipolar disorder.
Depression and suicide risk were assessed using the Mini-International Neuropsychiatric Interview Plus (MINI-Plus) instrument. Blood samples were analyzed for reactive species (DCFH), superoxide dismutase (SOD), and glutathione reduced (GSH).
“The percentage of women in our sample at risk of suicide (24.4%) at 18 months postpartum was of concern from the point of view of women’s health,” the researchers noted.
After adjusting for independent variables, the study found that of the oxidative stress biomarkers evaluated, only low levels of GSH were associated with the presence of suicide risk in the sample group.
“Likewise, we verified the difference in GSH levels according to the degree of suicide risk, observing a significant association between the differences in glutathione means in the group of women with moderate to high risk compared to the reference group (no suicide risk),” the researchers added.
The study called for further investigation of glutathione levels in a larger sample size to differentiate the potential association by manic or depressive episodes, as well as the use of N-acetyl-L-cysteine (NAC) – which the body converts into cysteine and then glutathione – as therapeutic agent for suicide risk intervention.
Source: Frontiers in Psychiatry
Can glutathione be a biomarker for suicide risk in women 18 months postpartum?
Authors: Paula Michele da Silva Schmidt et al.