In a groundbreaking discovery, researchers at the Fred Hutchinson Cancer Research Centre in the U.S., led by Mroj Alassaf, have unveiled a crucial connection between obesity and neurodegenerative diseases, such as Alzheimer's. This study, conducted using fruit flies, highlights how a high-sugar diet, a hallmark of obesity, triggers insulin resistance in the brain, reducing its ability to clear neuronal debris and increasing the risk of neurodegeneration.

Published in the open-access journal PLOS Biology, the research sheds light on the mysterious link between obesity and neurodegenerative disorders, providing valuable insights that could influence the development of medications aimed at minimizing the risk of acquiring such debilitating illnesses.

While the association between obesity and neurodegenerative disorders is well-known, the exact mechanisms underlying this connection have remained elusive. Leveraging the similarities between humans and fruit flies, the study focused on understanding this relationship. Previous research demonstrated that a high-sugar diet induces insulin resistance in the peripheral organs of fruit flies. Now, the researchers turned their attention to the brain, specifically examining glial cells due to their role in microglial dysfunction, a known precursor to neural degeneration.

The study revealed that a high-sugar diet led to reduced levels of the protein PI3k in glial cells, indicating insulin resistance. Additionally, ensheathing glia, the fly equivalent of microglia responsible for clearing neural debris, exhibited low levels of the protein Draper, signifying impaired function. Artificially reducing PI3k levels also resulted in insulin resistance and low Draper levels in ensheathing glia. Notably, when olfactory neurons were damaged, ensheathing glia in flies on a high-sugar diet couldn't effectively clear the degenerating axons due to insufficient increases in Draper levels.

The authors emphasized, "Using fruit flies, the authors establish that high-sugar diets trigger insulin resistance in glia, disrupting their ability to clear neuronal debris. This study provides insight into how obesity-inducing diets potentially contribute to the increased risk of neurodegenerative disorders."