Growth hormone-releasing hormone effects on brain gamma-aminobutyric acid levels in mild cognitive impairment and healthy aging

Summary

This randomized, double-blind, placebo-controlled study evaluated the effects of tesamorelin, a synthetic GHRH analog, on cognitive function and brain GABA levels in adults with mild cognitive impairment (MCI) and healthy older adults over 20 weeks. Tesamorelin treatment improved executive function and verbal memory and was associated with favorable changes in brain GABA levels measured by magnetic resonance spectroscopy.

Key Findings

• Tesamorelin treatment (2 mg daily) for 20 weeks improved executive function in both MCI and healthy aging groups as measured by multiple neuropsychological assessments
• Treated participants showed increased prefrontal GABA levels on magnetic resonance spectroscopy, suggesting enhanced inhibitory neurotransmission
• Improvements in cognition were correlated with changes in IGF-1 levels, supporting the role of the GH/IGF-1 axis in cognitive maintenance during aging