Human growth hormone showed the potential to improve the memory and cognitive function of mice post-stroke, raising the possibility of a similar treatment for humans.
Mental impairment affects up to 80 percent of stroke survivors, lead author Jörgen Isgaard, MD, PhD, and colleagues pointed out in Stroke. However, there are no recognized therapeutic options to prevent this outcome, they wrote.
Growth hormone has been associated with improved cognition following brain injury in experimental studies, but this is the first time its effect has been tested post-stroke, according to a press release.
Isgaard and coauthors induced strokes in mice and then treated them with either an infusion of growth hormone or a placebo for four weeks. During the last week of treatment, the mice underwent a paired-associate learning task in which they put pressure on a touchscreen in reaction to symbol patterns. They were then rewarded with a sugar solution for correct answers.
Overall, mice that had received growth hormone completed the tasks with a 22.4 percent higher correct rate. They performed correctly in about eight of 10 cases, while the mice in the placebo arm performed correctly in six of 10 cases.
"The most important new finding is that growth hormone improves cognition after a stroke compared with controls. If this finding holds true for humans, it can lead to a breakthrough in terms of treatment that facilitates rehabilitation and quality of life after a stroke," Isgaard said in the release.
The researchers also showed the growth hormone treatments reduced the loss of neural tissue, improved plasticity in the brain and enhanced the expression of insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF).
“Our findings of increased expression of neurotrophic factors, such as IGF-1 and VEGF, markers of synaptogenesis and myelination, and the formation of cerebrovascular networks confirm that GH has a wide range of neurorestorative effects that could have a potential in a clinical setting,” they wrote. “Encouragingly, some small and pilot studies in humans indicate a positive outcome when GH treatment is used together with specific rehabilitation after traumatic brain injury or stroke. The results from this study, supported by previous studies, suggest a rationale for clinical intervention studies with GH after stroke.”
Isgaard et al. said future studies may benefit from longer-term evaluations of memory and attention. In addition, they could assess whether different doses—or the timing of testing in relation to treatment—impact the effectiveness of the intervention.
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.