Consuming fatty meals within the days main as much as surgical procedure might immediate a heightened inflammatory response within the mind that interferes for weeks with memory-related cognitive operate in older adults – and, new analysis in animals suggests, even in younger adults.
The examine, constructing upon earlier analysis from the identical lab at The Ohio State College, additionally confirmed that taking a DHA omega-3 fatty acid complement for a month earlier than the unhealthy consuming and surgical process prevented the consequences on reminiscence linked to each the high-fat weight-reduction plan and the surgical procedure in aged and younger grownup rats.
Three days on a high-fat weight-reduction plan alone was detrimental to a selected kind of fear-related reminiscence in aged rats for so long as two weeks later – the identical kind of impairment seen in youthful rats that ate fatty meals and had a surgical process. The group has traced the mind irritation behind these results to a protein that prompts the immune response.
“These information counsel that these a number of insults have a compounding impact,” mentioned senior writer Ruth Barrientos, an investigator in Ohio State’s Institute for Behavioral Drugs Analysis and affiliate professor of psychiatry and behavioral well being and neuroscience within the Faculty of Drugs.
We have proven that an unhealthy weight-reduction plan, even within the quick time period, particularly when it is consumed so near a surgical procedure, which in and of itself will trigger an inflammatory response, can have damaging outcomes. The high-fat weight-reduction plan alone would possibly enhance irritation within the mind just a bit bit, however then you have got surgical procedure that does the identical factor, and when put collectively in a brief period of time you get a synergistic response that may set issues in movement towards a longer-term reminiscence concern.”
Ruth Barrientos, investigator in Ohio State’s Institute for Behavioral Drugs Analysis
The examine was printed lately within the journal Mind, Habits, and Immunity.
Barrientos’ lab research how on a regular basis life occasions would possibly set off irritation within the ageing mind because the nervous system responds to indicators from the immune system reacting to a risk. Many years of analysis has steered that with ageing comes long-term “priming” of the mind’s inflammatory profile and a lack of brain-cell reserve to bounce again.
Researchers fed younger grownup and aged rats a weight-reduction plan excessive in saturated fats for 3 days earlier than a process resembling exploratory belly surgical procedure – an occasion already identified to trigger a couple of week of cognitive points in an older mind. Management rats ate common meals and have been anesthetized, however had no surgical procedure. (Barrientos’ lab has decided anesthesia alone doesn’t trigger reminiscence issues in rats.)
On this examine, as in earlier analysis on aged rats handled with morphine after surgical procedure, the group confirmed that an immune system receptor known as TLR4 was the offender behind the mind irritation and associated reminiscence issues generated by each surgical procedure and the high-fat weight-reduction plan, mentioned first writer Stephanie Muscat, assistant scientific professor of neuroscience at Ohio State.
“Blocking the TLR4 signaling pathway previous to the weight-reduction plan and surgical procedure utterly prevented that neuroimmune response and reminiscence impairments, which confirmed this particular mechanism,” Muscat mentioned. “And as we had discovered earlier than in one other mannequin of an unhealthy weight-reduction plan, we confirmed that DHA supplementation did mitigate these inflammatory results and forestall reminiscence deficits after surgical procedure.”
There have been some shocking reminiscence findings within the new work. Completely different behavioral duties are used to check two forms of reminiscence: contextual reminiscence primarily based within the hippocampus and cued-fear reminiscence primarily based within the amygdala. In contextual reminiscence checks, rats with regular reminiscence freeze once they re-enter a room through which that they had an disagreeable expertise. Cued-fear reminiscence is clear when rats freeze in a brand new surroundings once they hear a sound linked to that earlier unhealthy expertise.
For aged rats on this examine, as anticipated, the mixture of a high-fat weight-reduction plan and surgical procedure led to issues with each contextual and cued-fear reminiscence that endured for no less than two weeks – a longer-lasting impact than the researchers had seen earlier than.
The high-fat weight-reduction plan alone additionally impaired the ageing rats’ cued-fear reminiscence. And in younger grownup rats, the mixture of the high-fat weight-reduction plan and surgical procedure led to solely cued-fear reminiscence deficits, however no issues with reminiscence ruled by the hippocampus.
“What that is telling us in aged animals, together with the actual fact we’re seeing this identical impairment in younger animals after the high-fat weight-reduction plan and surgical procedure, is that cued-fear reminiscence is uniquely susceptible to the consequences of weight-reduction plan. And we do not know why,” Barrientos mentioned. “One of many issues we’re hoping to know sooner or later is the vulnerability of the amygdala to those unhealthy weight-reduction plan challenges.”
With growing proof suggesting that fatty and extremely processed meals can set off inflammation-related reminiscence issues in brains of all ages, the constant findings that DHA – certainly one of two omega-3 fatty acids in fish and different seafood and obtainable in complement type – has a protecting impact are compelling, Barrientos mentioned.
“DHA was actually efficient at stopping these adjustments,” she mentioned. “And that is superb – it actually means that this might be a possible pretreatment, particularly if folks know they’ll have surgical procedure and their weight-reduction plan is unhealthy.”
This work was supported by grants from the Nationwide Institute on Growing older and the Nationwide Institute of Neurological Issues and Stroke.
Co-authors included Michael Butler, Menaz Bettes, James DeMarsh, Emmanuel Scaria and Nicholas Deems, all of Ohio State.
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Journal reference:
Muscat, S. M., et al. (2024). Put up-operative cognitive dysfunction is exacerbated by high-fat weight-reduction plan by way of TLR4 and prevented by dietary DHA supplementation. Mind, Habits, and Immunity. doi.org/10.1016/j.bbi.2023.12.028.