Obesity, a Growing Epidemic

As people consume more and more Big Macs and soda in this modern world full of processed foods, the rate of obesity is also growing exponentially within the U.S. as well as around the world. Jennifer Beshel gave a talk about how environmental factors along with genetic factors affect obesity. Genetically, leptin, a hormone produced by fat cells, regulates hunger through inhibition. Dr.Beshel, in her study "A Leptin Analog Locally Produced in the Brain Acts via a Conserved Neural Circuit to Modulate Obesity- Linked Behaviors in Drosophilia", knocks out a hormone similar in function to leptin, unpaired 1 (upd1), within the Drosophilia brain. She found that this knockout led to an increase of food intake, attraction to food cues, and weight as compared to wild type, showing that genetics play a role in obesity. Furthermore, the effects of the environment were also tested by placing the flies on a high-sugar and high-fat diet, much like the modern world. Although both wild-type and knockout flies gained weight when placed on this diet, the knockout flies gained three times as much weight as the wild type, showing that obesity is not only a genetic concern, but an environmental one as well.  

As obesity becomes a growing epidemic, obesity-associated issues are also on the rise and a pose a problem for our modern society. One article, "Microglia Play an Active Role in Obesity-Associated Cognitive Decline" by Elise C. Cope et al., finds pernicious effects of obesity on the hippocampus in male mice. The article found that obese male mice had an increase in the activation of microglia within the hippocampus and other areas of cognitive impairment. This is likely to be the cause of cognitive decline as a reduction of dendritic spines was also seen among these areas. This was also confirmed through a partial knockdown of a receptor required for microglial activation and through inhibition of microglial activation using pharmaceutical drugs. In both cases it was found that the prevention of microglial activation among obese mice also prevented cognitive degradation. 

All in all, obesity is a growing epidemic which is caused not only through genetic factors, but environmental factors as well. As obesity becomes a problem within the U.S. and the around the world, so does the issues associated with it such as cognitive decline. 

Works Cited: 

Beshel, Jennifer, et al. “A Leptin Analog Locally Produced in the Brain Acts via a Conserved Neural Circuit to Modulate Obesity-Linked Behaviors in Drosophila.” Cell Metabolism, vol. 25, no. 1, 2017, pp. 208–217., doi:10.1016/j.cmet.2016.12.013.

Cope, Elise C., et al. “Microglia Play an Active Role in Obesity-Associated Cognitive Decline.” The Journal of Neuroscience, vol. 38, no. 41, 2018, pp. 8889–8904., doi:10.1523/jneurosci.0789-18.2018.