The study found that older adults with more chemical tags (methylation) on the oxytocin‑receptor gene and who feel more stressed also have higher levels of inflammation in their blood. This suggests the gene’s methylation may be a bridge between stress and age‑related inflammation.

Oxytocin (OT) is a neuropeptide involved, among other functions, in the regulation of stress and inflammation. OT's impact on inflammatory and stress-related processes is particularly relevant in older adults, given that elevated levels of systemic inflammation typically associated with age can be amplified by stress. Methylation of the OT receptor gene (OXTRm) is an epigenetic process that reduces the availability of receptors to bind with OT. While acute stress has been shown to increase OXTRm levels in older adults, the interplay of OXTRm and stress on inflammation remains unexamined. This study collected blood samples from 116 generally healthy older adults (M_age = 71.2 years, SD = 7.51 years, range = 55-95 years) to quantify methylation OXTRm at CpG site -924 and tumor necrosis factor (TNF)-α as biomarkers of systemic inflammation, as well as assessed self-reported levels of stress. Moderated linear regression revealed that higher OXTRm methylation levels and greater perceived stress were associated with greater systemic inflammation (B = 0.24, p = 0.006). These findings highlight OXTRm as an epigenetic pathway linking stress and inflammation in aging.