Scientists study the link between obesity, age and body chemistry

Scientists study the link between obesity, age and body chemistry

Journal of Lipids (2022). DOI: 10.1155/2022/7122738″ width=”800″ height=”530″/>

Comparison of total body weight, liver and WAT between all treatment groups. For all treatment groups, total body weight, liver weight, somatic liver index (HSI), WAT weight, and somatic WAT index (WSI) were measured. The data is presented as . Statistical significance was determined using a one-way ANOVA multiple comparison test with Tukey’s multiple comparison test as a post hoc test (1). “a” (age) indicates the difference in age between young (4.5 months) and old (9 months) mice in a group with the same genotype and diet, “c” (catch) indicates the difference between young (4.5 months) and ND-feeding. old (9 mo) mice of the same genotype were fed, “d” (diet) indicates the difference in diet between mice treated with ND and HFD within the same genotype and age, and “g” (genotype) indicates the difference in genotypes between WT and Cyp2b. -null mice in the same diet and age group. The absence of an asterisk indicates the value of Journal of Lipids (2022). DOI: 10.1155/2022/7122738

A team of scientists at Clemson University is trying to understand the relationship between certain enzymes normally produced in the body and their role in regulating obesity and controlling liver disease.

More than 42% of US adults and 19% of US youth are obese, according to data from the Centers for Disease Control and Prevention (CDC) collected in 2017-2018.

The three Clemson researchers and their colleagues at Emory University School of Medicine studied male mice that lacked the Cyp2b enzyme and how the lack of the enzyme affected the mice’s metabolism.

William Baldwin, professor and graduate program coordinator at the Clemson Department of Biological Sciences, said the study was prompted in part by a simple observation that male mice that lacked the Cyp2b enzyme gained weight. The same effect was not observed in Cyp2b null female mice.

“We noticed that our Cyp2b null mice were heavier,” said Baldwin, a professor in the Department of Biological Sciences. “They are more prone to obesity – at least diet-induced obesity – especially in males, than wild-type mice, and we tried to find out why this is so.”

Although the observation that prompted the researchers was fairly simple, it turned out that understanding the interaction behind weight gain would be much more difficult.

“It would be nice if there was a good and simple answer,” Baldwin said, “but there probably isn’t a good simple answer.”

Variety of roles

Baldwin noted the complexity of the many chemical processes involved in the CYP enzyme, which is part of a superfamily of enzymes that play different roles in the human body. He said the Cyp2b enzymes help metabolize certain toxicants and drugs to remove them from the body.

But the same CYP enzymes do other jobs as well. “They metabolize bile acids, they metabolize steroid hormones, they metabolize polyunsaturated fats from our diet,” Baldwin said. “It means that all these things can also interact. If your diet is high in fat, this can interfere with drug metabolism. Sure…drugs can interfere with fat metabolism, they can interfere with steroid metabolism, and so on.”

The researchers also looked at the link between “disturbed lipid profiles” and disease.

The researchers noted that disease susceptibility and overall health are highly dependent on lipidoma changes. High-fat diets, such as the Western diet, cause obesity and drastically alter liver lipidomas, and disturbed lipid profiles are associated with certain liver diseases such as non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH).






Credit: Clemson University.

The influence of age and diet

Baldwin led previous research on the relationship between diet and environmental toxicants. The most recent research has focused on the effect of age and diet on these metabolic processes.

“What does bad nutrition do to us? What does age do to us? That’s the idea here,” Baldwin said of the latest study. “We are looking at these enzymes; what might happen over time to our profiles in this mouse model compared to just wild-type mice. What can happen over time on a high-fat diet, what can happen with age, and how it differs between this one mouse model that does not have these enzymes versus one that does.”

Simply put, Baldwin said, “One of the things we’ve seen, and it’s not surprising, is that aging is bad. It is more difficult for mice to regulate body weight. They are gaining weight. [connective tissue mainly comprising fat cells]. … And some of these things were a little worse in mice that lacked the Cyp2b enzymes. They were a little heavier. They had slightly more fat than their counterparts. Their livers were slightly larger and slightly less healthy. So they had a lot of those things that we associate with age.”

The diet also had an impact on the health of the mice.

“Of course the diet didn’t help either,” Baldwin continued. “This is the same case: poor nutrition caused weight gain, and these were a little worse. [Cyp2b-null] mice, probably due to poor metabolism.”

He said the exact mechanism by which the Cyp2b enzyme works is not fully understood.

“You take away an enzyme that helps metabolize them, but I don’t think it’s really important that it helps get rid of fat, but that it lets the body know that fat is there. It probably produces signal molecules that say, hey, we need to decide what we’re going to do with this fat, we need to distribute this fat.” Such information. It’s just an educated guess at this point, but I think that’s probably what’s happening.”

Differences in people

Baldwin said his current study takes a closer look at the mechanisms involved and how they differ in a human model from studies in mice. He said the study, which will be part of an as-yet unpublished paper, shows that mouse and human enzymes probably don’t work the same way. “The human enzyme seems to make us store some of the fat in the liver, while the mouse enzyme seems to direct it to white adipose tissue. There are hints in this article that this is the case,” Baldwin said.

The results of the study were published in Journal of Lipids in an article entitled “Age-related and dietary changes in hepatic lipidoma profiles of phospholipids in male mice: age-related acceleration in Cyp2b null mice”.


Researchers Link Metabolic Enzyme to Obesity and Fatty Liver Disease


Additional Information:
Melissa M. Heinz et al., Age- and diet-dependent changes in hepatic lipidoma profiles of phospholipids in male mice: age-related acceleration in Cyp2b gene null mice, Journal of Lipids (2022). DOI: 10.1155/2022/7122738

Courtesy of Clemson University.

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