A new paper published in Medicine suggests that Heat shock proteins CPN10, CPN60, and CPN70 could act as biomarkers for bipolar disorder (BD). Moreover, CPN60 serum levels could act as a biomarker to specify which BD patients have abnormal activity of the hypothalamic-pituitary-adrenal (HPA) axis.

“An association has been observed between BD and abnormal activity of the hypothalamic-pituitary-adrenal (HPA) axis, which plays an important role in the response to stress, although the role of HPA axis activity abnormalities in the pathophysiology of BD remains unclear,” wrote the authors, led by Yuhang Cheng, MD, The National Clinical Research Center for Mental Disorders and Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing. Results of a recent meta-analysis uncovered a significant link between BD and both cortisol (CORT) and adrenocorticotropic hormone (ACTH).

 “Originally, it was believed that HSP only had intracellular functions, but evidence has been accumulating that they also have extracellular functions,” the authors wrote. HSPs may also help in immune function in addition to facilitating the folding of proteins.

Numerous studies have signified that HSP is concerned with BD pathogenesis. Therefore, HSPs could serve as biomarkers for BD. This is a table-turner, as there are presently no BD biomarkers. In the existing study, investigators screened HSP candidates as probable in vivo biomarkers in patients having both BD and BD with abnormal HPA activity.

 “Our findings in this preliminary study suggest that HSP potentially might be useful as a biomarker of BD and for distinguishing BD patients with abnormal HPA axis activity from BD patients with normal HPA axis activity,” the authors wrote. “Our results may eventually be useful for making an earlier diagnosis and therefore being able to initiate treatment for BD earlier.”