# Oral Supplementation of L-Carnosine Attenuates Acute-Stress-Induced Corticosterone Release and Mitigates Anxiety in CD157 Knockout Mice

## TL;DR

L-carnosine reduces stress hormone levels and anxiety in mice with a genetic mutation linked to autism.

## Contribution

This study shows L-carnosine's potential to reduce stress and anxiety in a mouse model of autism.

## Key findings

- L-carnosine reduced plasma corticosterone levels in response to acute stress in CD157 knockout mice.
- L-carnosine attenuated anxiety-like behaviors in CD157 knockout mice.
- The results suggest L-carnosine may help manage stress-related anxiety in individuals with ASD.

## Abstract

Corticosterone, an end product of the hypothalamic–pituitary–adrenal (HPA) axis, is a crucial stress hormone. A dysregulated HPA axis and corticosterone release play pivotal roles in the onset and persistence of symptoms of stress-related psychiatric disorders, such as anxiety. The intake of nutrients, probiotics, and prebiotic supplements decreases blood corticosterone levels. The dipeptide L-carnosine is composed of beta-alanine and L-histidine and is commercially available as a nutritional supplement for recovery from fatigue. L-carnosine is involved in stress-induced corticosterone responses and anxiety behaviors in rodents. Here, we assessed the effect of L-carnosine in CD157 knockout (KO) mice, a murine model of autism spectrum disorder (ASD). The uptake of L-carnosine suppressed the increase in plasma corticosterone levels in response to acute stress and attenuated anxiety-like behaviors in CD157 KO mice. These results suggest that L-carnosine supplementation may relieve anxiety by suppressing excessive stress responses in individuals with ASD.