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Growth hormone-releasing hormone had positive effect on cognition

Treatment with growth hormone-releasing hormone was associated with positive cognitive effects among adults with mild cognitive impairment and healthy older adults, according to study results.

Laura D. Baker, PhD, of the University of Washington School of Medicine and Veterans Affairs Puget Sound Health Care System in Seattle, and colleagues conducted a randomized, double-blind, placebo-controlled trial involving 152 adults, 66 of whom had mild cognitive impairment. Participants, aged 55 to 87 years, were assigned to self-administer daily subcutaneous injections of tesamorelin (Egrifta, Theratechnologies), a stabilized analog of human growth hormone-releasing hormone (GHRH), or placebo 30 minutes before bedtime for 20 weeks.

Researchers collected blood samples at baseline, at weeks 10 and 20 of treatment, and again at 10 weeks following the conclusion of treatment. Participants completed a battery of tests measuring executive function, verbal memory and visual memory.

Intent-to-treat analysis showed that GHRH had a positive effect on cognition (P=.03), with comparable results between adults with mild cognitive impairment and healthy older adults. Completer analysis indicated a similar pattern, with a more “robust GHRH effect,” according to researchers (P=.002). GHRH was found to have a positive effect on executive function (P=.005) and verbal memory (P=.08). Visual memory was not significantly affected by GHRH treatment. Among those treated with GHRH, serum levels of insulin-like growth factor 1 increased by 117% (P<.001). GHRH decreased body fat by 7.4% (P<.001), and increased lean muscle mass by 3.7% (P<.001).

Results also showed that treatment with GHRH increased fasting insulin levels by 35% in adults with mild cognitive impairment (P<.001), but not in healthy older adults. Adverse events were mild, according to the researchers, reported by 68% of participants treated with GHRH and 36% of those in the control group.

“The potential to preserve, or even enhance, cognitive function in normal aging and in populations where cognitive functions are failing rapidly owing to neurodegenerative disease clearly has important implications not only for the affected individual but also for the support system that bears the social and financial burdens of long-term caregiving,” the researchers wrote. “GHRH administration has favorable effects on cognitive function not only in healthy older adults but also in adults at increased risk of cognitive decline and dementia.”

Disclosure: Tesamorelin and placebo were provided at no cost to the study by Theratechnologies, Inc.