An increase in the stress hormone corticosterone that is caused by diabetes leads to deficits in the birth of new neurons and memory formation in rodents, according to a study published online in Nature Neuroscience. Altering a similar stress hormone in diabetic patients may help reverse cognitive impairments in people with high blood sugar levels.
Until now, the mechanism underlying the cognitive dysfunction seen in patients with diabetes has been unknown. Mark Mattson and colleagues now demonstrate that lowering corticosterone in a rodent diabetes model reverses several adverse effects, including the reduced birth of new neurons, altered synaptic plasticity and impaired memory, and restores relatively normal brain function. These deficits did not depend on changes in insulin production, as the same cognitive deficits could be reversed in an insulin-resistant model of diabetes by returning corticosterone levels to normal. Enhancement of brain function by normalizing corticosterone levels in diabetic animals could be reversed completely by administering high levels of corticosterone.
Though further research will be required to determine whether these results are applicable to people, this study suggests a potential strategy for treating diabetic patients suffering from disease-induced cognitive impairments.
Mark Mattson (National Institute on Aging, Baltimore, MD, USA)
Abstract available online.
(C) Nature Neuroscience press release.
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