Neuropeptide in blood may lead to targeted treatment for chronic itch

Photo by Credit: Estzer Miller via Pixabay

A new study has identified what may be the first biomarker for chronic itch.

Published in Drugs in Dermatology, researchers from the University of Miami Miller School of Medicine report B-type natriuretic peptide (BNP) plays a key role in chronic itch severity. They say a blood test for this peptide may ultimately help to identify and differentiate certain types of itch.

BNP and its metabolite, aminoterminal pro B-type natriuretic peptide (NT-proBNP), correlate with itch intensity. The correlation is particularly strong in patients with chronic pruritus of unknown origin, a term Dr. Gil Yosipovitch coined in a paper published 11 years ago in the New England Journal of Medicine. He is an author of the current study.

“The majority of patients with chronic pruritus of unknown origin are elderly and their itch is challenging to diagnose and treat because the cause is unknown and they do not have a primary skin rash,” Dr. Yosipovitch said in a news release. “Their lives are often miserable from the unrelenting itching and there is no targeted treatment.” He is a professor of dermatology and cutaneous surgery and Stiefel Chair in Medical Dermatology at the Miller School of Medicine.

Researchers studied plasma BNP levels in 77 human tissue samples and an additional 33 patients with different chronic itch types. BNP and NT-proBNP levels correlated with itch severity in all patients, but patients with chronic pruritus of unknown origin were most impacted.

In a corresponding animal study model, they demonstrated that increasing BNP levels could induce significant scratching, and that BNP activates the natriuretic peptide receptor A in the spinal cord. In spinal cords of mice, high levels of BNP can induce itch through central pathways.

The researchers also noted that BNP is a biomarker for congestive heart failure, cardiac dysfunction, and kidney failure, although in this study they did not find an association between cardiac dysfunction and itch.

For the investigators, the question is whether or not reducing BNP results in less itch. Dr. Yosipovitch and colleagues are now conducting a follow-up study.