A new study suggests that treatment with growth hormone-releasing hormone (GHRH) may aid cognition among cognitively impaired and healthy older adults.
The finding that growth hormone-releasing hormone aids cognition in mildly impaired individuals, as well as healthy older adults, supports earlier studies.
“Growth hormone-releasing hormone, growth hormone and insulinlike growth factor 1 have potent effects on brain function, their levels decrease with advancing age, and they likely play a role in the pathogenesis of Alzheimer disease,” state the authors.
Researchers conducted a randomized, double-blind, placebo-controlled trial in which participants self-administered daily injections of a form of human GHRH (tesamorelin), or placebo to investigate the benefits of GHRH.
Laura D. Baker, Ph.D., of the University of Washington School of Medicine and colleagues enrolled 152 adults ranging in age from 55 to 87 years (average age of 68 years).
One hundred thirty-seven participants (76 healthy patients and 61 patients with MCI) successfully completed the study.
Researchers collected blood samples and administered parallel versions of cognitive tests at baseline, at 10 and 20 weeks of treatment, and after a 10-week washout (30 weeks total).
Among the original 152 patients enrolled in the study, analysis indicated a favorable effect of GHRH on cognition, which was comparable in adults with MCI and healthy older adults.
Researchers determined that among the 137 patients who successfully completed the trial, treatment with GHRH had a improved cognition among both groups of patients. Although the healthy adults outperformed those with MCI overall, the cognitive benefits relative to placebo was comparable among both groups. Treatment with GHRH also increased improved insulin regulation.
“Our results replicate and expand our earlier positive findings, demonstrating that 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,” the authors conclude.
“Larger and longer-duration treatment trials are needed to firmly establish the therapeutic potential of GHRH administration to promote brain health in normal aging and ‘pathological aging.’”
Results from the randomized clinical trial are published in Online First by Archives of Neurology.