Why do some obese people have 'healthier' fat tissue than others?

November 01, 2017

ANN ARBOR--One little understood paradox in the study of obesity is that overweight people who break down fat at a high rate are less healthy than peers who store their fat more effectively.

That's because when fat breaks down, many of the fatty acids released from the adipose tissue (body fat) can take up residence elsewhere. Too much of this and fat can accumulate to harmful levels in other tissues and organs, which can fuel insulin resistance, a hallmark of type 2 diabetes and heart disease.

A pair of studies from the University of Michigan identifies key characteristics in fat tissue that may allow some obese adults to store their body fat more healthily and suggests that aerobic exercise may lead to healthier fat storage, said principal investigator Jeffrey Horowitz, professor of movement science at the U-M School of Kinesiology.

Most obese people develop insulin resistance, which can lead to type 2 diabetes and other chronic diseases. However, Horowitz and his team found that about one-third of the 30 obese adults in their study did not develop insulin resistance.

This begged the question: What protected these people?

Adipose tissue samples revealed that the healthier group broke down fat at slower rates, and they had fewer proteins involved in fat breakdown and more involved in fat-storing. They also had fewer fibrotic cells in the adipose tissue, which allows tissue to be more flexible, and lower activation of certain inflammatory pathways.

"It sounds counterintuitive, but if we can better understand how to store fat more effectively, and why some people are better at this than others, perhaps we can design therapies and preventions that will improve some of these obesity-related metabolic conditions," Horowitz said.

In the second study, researchers collected fat tissue after a session of aerobic exercise from two groups of overweight people: one group exercised regularly, and the other group didn't. For both groups, just one session of exercise triggered signals that led to the growth of new blood vessels in fat tissue.

Researchers also found indications that the regular exercisers had more blood vessels in their fat tissue than non-exercisers.

That's important because the health of most tissues hinges, in large part, on blood flow and nutrients, Horowitz said. When we gain weight, our fat cells expand, but if blood flow to fat tissue doesn't increase in parallel, it could become unhealthy or even necrotic.

Horowitz stressed that the two studies are relevant mainly to obese people at risk for metabolic disease. However, there's a takeaway here for everyone.

"We believe that the regular exercise we do now may create a healthier fat-storing environment for those times when we do overeat and gain weight," Horowitz said.

Taken together, the studies also support the notion that clinicians must redefine their view of fat, said Horowitz.

"Adipose tissue is scorned because most people see it as causing disease and obesity, but in general adipose tissue doesn't cause people to gain weight and become obese, it's just where we store our extra energy when we do overeat," Horowitz said. "Our studies aren't suggesting it is healthy to be obese or to overeat--but when we do overeat, it is important to have a safe place to store that extra energy.

"When people gain the same amount of body fat, those with adaptations to their fat tissue that can more healthfully accommodate the extra fat may be protected from developing insulin resistance and obesity-related diseases. We have identified some of these adaptations."

Doug Van Pelt, a former doctoral student in the Horowitz lab, conducted this work as part of his dissertation. Van Pelt is currently a postdoctoral fellow at the University of Kentucky's College of Health Sciences.

The two studies are: "Factors regulating subcutaneous adipose tissue storage, fibrosis, and inflammation may underlie low fatty acid mobilization in insulin-sensitive obese adults" and "Aerobic exercise elevates markers of angiogenesis and macrophage IL6 gene expression in the subcutaneous adipose tissue of overweight to obese adults."
-end-


University of Michigan

Related Diabetes Articles from Brightsurf:

New diabetes medication reduced heart event risk in those with diabetes and kidney disease
Sotagliflozin - a type of medication known as an SGLT2 inhibitor primarily prescribed for Type 2 diabetes - reduces the risk of adverse cardiovascular events for patients with diabetes and kidney disease.

Diabetes drug boosts survival in patients with type 2 diabetes and COVID-19 pneumonia
Sitagliptin, a drug to lower blood sugar in type 2 diabetes, also improves survival in diabetic patients hospitalized with COVID-19, suggests a multicenter observational study in Italy.

Making sense of diabetes
Throughout her 38-year nursing career, Laurel Despins has progressed from a bedside nurse to a clinical nurse specialist and has worked in medical, surgical and cardiac intensive care units.

Helping teens with type 1 diabetes improve diabetes control with MyDiaText
Adolescence is a difficult period of development, made more complex for those with Type 1 diabetes mellitus (T1DM).

Diabetes-in-a-dish model uncovers new insights into the cause of type 2 diabetes
Researchers have developed a novel 'disease-in-a-dish' model to study the basic molecular factors that lead to the development of type 2 diabetes, uncovering the potential existence of major signaling defects both inside and outside of the classical insulin signaling cascade, and providing new perspectives on the mechanisms behind insulin resistance in type 2 diabetes and possibly opportunities for the development of novel therapeutics for the disease.

Tele-diabetes to manage new-onset diabetes during COVID-19 pandemic
Two new case studies highlight the use of tele-diabetes to manage new-onset type 1 diabetes in an adult and an infant during the COVID-19 pandemic.

Genetic profile may predict type 2 diabetes risk among women with gestational diabetes
Women who go on to develop type 2 diabetes after having gestational, or pregnancy-related, diabetes are more likely to have particular genetic profiles, suggests an analysis by researchers at the National Institutes of Health and other institutions.

Maternal gestational diabetes linked to diabetes in children
Children and youth of mothers who had gestational diabetes during pregnancy are at increased risk of diabetes themselves, according to new research published in CMAJ (Canadian Medical Association Journal).

Two diabetes medications don't slow progression of type 2 diabetes in youth
In youth with impaired glucose tolerance or recent-onset type 2 diabetes, neither initial treatment with long-acting insulin followed by the drug metformin, nor metformin alone preserved the body's ability to make insulin, according to results published online June 25 in Diabetes Care.

People with diabetes visit the dentist less frequently despite link between diabetes, oral health
Adults with diabetes are less likely to visit the dentist than people with prediabetes or without diabetes, finds a new study led by researchers at NYU Rory Meyers College of Nursing and East Carolina University's Brody School of Medicine.

Read More: Diabetes News and Diabetes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.