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"Depression, memory, and the IGF-1 receptor are all located in a brain region which regulates a lot of complicated cognitive ability," says Feng Lin. "As circulating IGF-1 can pass through the blood-brain barrier, it may work to influence the brain in a protective way." (Credit: iStockphoto)

aging

Hormone seems to connect depression, memory loss

Past research has long indicated that depression is a big risk factor for memory loss in aging adults. But it is still unclear exactly how the two issues are related and whether there is potential to slow memory loss by fighting depression.

A preliminary study, published in Psychoneuroendocrinology, delves more deeply into the relationship between depression and memory loss, and how this connection may depend on levels of insulin-like growth factor, or IGF-1.

Prior research has shown that IGF-1, a hormone that helps bolster growth, is important for preserving memory, especially among older adults.

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The collaborative study finds that people with lower cognitive ability were more likely to have had higher depressive symptoms if they also had low levels of IGF-1. Reversely, participants with high levels of IGF-1 had no link between depressive symptoms and memory.

Three factors

Senior author Kathi L. Heffner, assistant professor in the University of Rochester School of Medicine and Dentistry’s department of psychiatry, had originally examined possible associations between IGF-1 and memory in a sample of 94 healthy older adults, but couldn’t find strong or consistent evidence.

Heffner then approached the study’s lead author Feng (Vankee) Lin, assistant professor at the School of Nursing, for input because of her expertise in cognitive aging. Lin is a nurse researcher whose collaborative work focuses on developing multi-model interventions to slow the progression of cognitive decline in at-risk adults, and reduce their risk of developing dementia and Alzheimer’s disease.

“Vankee spearheaded the idea to examine the role of depressive symptoms in these data, which resulted in the interesting link,” Heffner says.

The association discovered between memory loss, depression, and IGF-1 means that IGF-1 could be a very promising factor in protecting memory, Lin says.

“IGF-1 is currently a hot topic in terms of how it can promote neuroplasticity and slow cognitive decline,” Lin says.

“Depression, memory, and the IGF-1 receptor are all located in a brain region which regulates a lot of complicated cognitive ability. As circulating IGF-1 can pass through the blood-brain barrier, it may work to influence the brain in a protective way.”

Future applications

Lin says more data studies are needed of people with depression symptoms and those with Alzheimer’s disease, but this study opens an important door for further research on the significance of IGF-1 levels in both memory loss and depression.

“It really makes a lot of sense to further develop this study,” Lin says. “If this could be a way to simultaneously tackle depression while preventing cognitive decline it could be a simple intervention to implement.”

Heffner says that clinical trials are underway to determine whether IGF-1 could be an effective therapeutic agent to slow or prevent cognitive decline in people at risk.

“Cognitive decline can also increase risk for depressive symptoms, so if IGF-1 protects people from cognitive decline, this may translate to reduced risk for depression as well,” Heffner says.

Researchers from Ohio University and Texas Tech University Health Sciences Center contributed t the study. Funding came from the National Institute on Aging and University of Rochester CTSA award, and from the National Center for Advancing Translational Sciences of the National Institutes of Health.

Source: University of Rochester

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