The salutary effects of DHA dietary supplementation on cognition, neuroplasticity, and membrane homeostasis after brain trauma

Journal of Neurotrauma October 2011; Vol. 28; No. 10; pp. 2133-2122 Aiguo Wu, Zhe Ying, Fernando Gomez-PinillaDepartment of Integrative Biology and Physiology, University of California at LosAngeles KEY POINTS FROM THIS ARTICLE: 1) Traumatic brain injury (TBI) is one of the most common causes of death anddisability in United States: 220,000 hospitalizations, 52,000 deaths from headtrauma, and 80,000-90,000 patients suffering from permanent disability eachyear. 2) Even though over 30 major clinical trials have been made, no efficienttreatment for TBI has been found to date. 3) TBI results in long lasting consequences on the cognitive ability of patients. 4) The pathology of traumatic brain injury is characterized by membranedamage, oxidative stress, failure in the capacity of neurons to metabolize energy,sustain synaptic function, and likely resulting in cognitive and emotional disorders. 5) These authors assessed the potential of the omega-3 fatty aciddocosahexaenoic acid (DHA) to counteract the effects of concussive injury onimportant aspects of neuronal function and cognition. 6) Fluid percussion injury (FPI) or sham injury was performed on rats whichwere then maintained on a diet high in DHA (1.2% DHA) for 12 days. 7) DHA supplementation improves learning ability in FPI rats. 8) Given the involvement of SOD [superoxide dismutase endogenousantioxidant] and Sir2 [a longevity gene] in promoting metabolic homeostasis, DHAmay help the TBI brain by providing resistance to oxidative stress. 9) The overall results emphasize the potential of dietary DHA to counteractbroad and fundamental aspects of the TBI pathology that can translate in preservedcognitive capacity. 10) Dietary supplementation of fish oil before brain injury can protect the brainfrom the deleterious effects of TBI on cognition and plasticity.2 11) DHA is a crucial omega-3 fatty acid abundant in the brain, is important forbrain development and plasticity, and has been shown to support learning andmemory neurodegerative disorders such as Alzheimers. 12) This study investigated the healing capacity of DHA dietary supplementationwhen provided immediately after a concussive injury in rats. 13) There is a homeostatic effect of DHA dietary supplementation when providedimmediately after TBI. 14) A short period of DHA supplementation significantly counteracted thenegative effects of the injury on cognitive function, neuronal signaling, andmembrane homeostasis. 15) These results indicate that DHA supplementation can provide the type ofbroad protection important for counteracting the effects of TBI. 16) Given the role of DHA in membrane homeostasis and neuronal signaling,these findings implicate dietary DHA as a potential candidate for counteracting theadverse effects of TBI on synaptic plasticity and cognition. 17) Short time feeding of DHA significantly unregulated molecules withrecognized antioxidant capacity such as SOD and Sir2. DHA upregulates SOD andSir2, which may contribute to counteracting oxidative damage to plasma membraneafter TBI. 18) The increase in DHA content may help maintain membrane fluidity, therebypreserving cognitive function in TBI animals. 19) It is known that TBI causes degradation of membrane phospholipids. Synapticmembranes phospholipids are preferentially enriched in omega-3 fatty acid DHA.Increased DHA content helps prevent the loss of DHA from membrane lipids. 20) Our findings suggest that supplementation of DHA may help the TBI brainpreserve synaptic membrane integrity and fluidity, thereby enhancing membranerelated cellular function and subsequent cognitive improvement. 21) Our results demonstrate that DHA dietary supplementation appliedimmediately after TBI counteracts the related cognitive decay.