Obese fat becomes inflamed and scarred, which may make weight loss harder

January 12, 2018, University of Exeter
Obese fat becomes inflamed and scarred, which may make weight loss harder
Fat in obese people can suffocate and struggle for oxygen supply. Credit: University of Exeter

The fat of obese people becomes distressed, scarred and inflamed, which can make weight loss more difficult, research at the University of Exeter has found.

An analysis of the health of adipose (fat) in overweight found that their fat can cease to cope as it increases in size and becomes suffocated by its own expansion.

Dr. Katarina Kos, Senior Lecturer at the University of Exeter's Medical School, examined samples of fat and tissue from patients, including those with problems who have undergone bariatric surgery.

Fat in can suffocate and struggle for oxygen supply, due in part to the increase in the ' size. As cells get bigger they become distressed and struggle for oxygen which triggers inflammation in the fat tissue. The inflammation spills over from fat tissue into the blood stream and is eventually measurable in the circulation by a blood test.

Stressed and unhealthy fat tissue is also less able to accommodate more unused dietary energy. With fat tissue not being able to do its most vital job, which is storing excess calories, the excess energy can be increasingly diverted from fat tissue to vital organs, including the liver, muscle and heart. This can lead to obesity-related health complications such as fatty liver disease and cardiovascular disease.

Dr. Kos found that fat tissue which is fibrous is also stiffer and more rigid. Previous studies of people who have had surgery showed that increased levels of can make it harder to lose weight.

"Scarring of fat tissue may make weight loss more difficult," Dr. Kos said. "But this does not mean that scarring makes weight loss impossible. Adding some regular activity to a somewhat reduced energy intake for a longer period makes weight loss possible and helps the fat tissue not to become further overworked. We know that doing this improves our blood sugar and is key in the management of diabetes."

Dr. Kos, who leads the adipose tissue biology group at the University of Exeter, said where obese people carry their fat can have an impact on their health.

Scarring of fat tissue can change a person's body shape. They can develop an 'apple' body shape with a large tummy and more fat within the deeper layers of the tummy and around the organs. However, they can retain thin arms and legs, as there is little fat just below the skin. Although such people can appear relatively slim, fat can be deposited in their abdomen and in their internal organs, including their liver, pancreas, muscle and the heart. Fat can also be stored around and in the arteries causing arteriosclerosis, a stiffening of arteries predisposing people to high blood pressure, heart disease and strokes. Scarring of fat tissue has also been linked to diabetes.

"One could have very little fat below the skin and still be at risk of diabetes due to a lot of fat within the abdomen and inner organs," Dr. Kos said.

Dr. Kos, a clinician and specialist in adipose tissue physiology and obesity-related disorders, studied the abdominal fat tissue of obese people which had become fibrous or 'scarred' in order to identify what regulates this scarring and to look at how to reverse it. Scarring makes fat tissue less able to expand and less able to store nutritional energy surplus to its needs.

The research published in the journal Metabolism, examined a molecule called Lysyl oxidase (LOX) which regulates scarring by making tissue stiffer. The study, Lysyl oxidase and adipose tissue dysfunction, found that this molecule is more prevalent in fat tissue of obese people and that it was increased by inflammation and oxygen deprivation.

Dr. Kos and her team examined fat tissues from patients who had undergone bariatric surgery and who gave permission for samples of adipose tissue to be examined. She also compared the properties of adipose tissue with leaner subjects who had undergone elective surgical procedures. There was a higher accumulation of the LOX molecule which regulates scarring in obese patients. Those with a higher BMI also tended to have more of the LOX gene expressed in their . She found that low oxygen levels and inflammation were the main drivers of higher LOX levels. The team also found that LOX was not influenced by major weight loss after .

Dr. Kos added: "Further research is needed to determine how to avoid our fat tissue becoming unhealthy and how protect it from inflammation and scarring. There is evidence that once fat tissue becomes scarred, despite weight loss, it may not recover fully. We need to look after our fat tissue which can cease to cope if it is overworked when being forced to absorb more and more calories. As a clinician, I would advise exercise or at least a 'walk' after a meal which can make a great difference to our metabolic health."

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

More information: Emilie Pastel et al. Lysyl oxidase and adipose tissue dysfunction, Metabolism (2017). DOI: 10.1016/j.metabol.2017.10.002

Related Stories

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

November 1, 2017
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.

Bariatric surgery improves adipose tissue function

June 20, 2016
(HealthDay)—Bariatric surgery is associated with improvements in adipose tissue function, some of which are independent of weight loss, according to research published online June 8 in Obesity Reviews.

Mechanism that converts white fat to brown identified

January 8, 2018
An international team of researchers led from Karolinska Institutet have, in experiments on mice, pinpointed a mechanism for the conversion of energy-storing white fat into energy-expending brown fat. The study is published ...

In obese patients, five percent weight loss has significant health benefits

February 22, 2016
For patients with obesity trying to lose weight, the greatest health benefits come from losing just 5 percent of their body weight, according to a new study at Washington University School of Medicine in St. Louis.

A specific protein regulates the burning of body fat to generate heat

October 11, 2017
Scientists at the Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) have identified a protein that holds promise as a target for therapies to reduce obesity. Drs. Guadalupe Sabio and Nuria Matesanz have ...

A potential role for fat tissue as an HIV reservoir and source of chronic inflammation

September 24, 2015
Viral persistence and chronic inflammation are two key features of HIV-positive patients on antiretroviral therapy (ART). A study published on September 24th in PLOS Pathogens reports results from macaques and humans that ...

Recommended for you

Synthetic sandalwood found to prolong human hair growth

September 19, 2018
A team of researchers led by Ralf Paus of the University of Manchester has found that applying sandalwood to the scalp can prolong human hair growth. In their paper published in the journal Nature Communications, the group ...

Separated entry and exit doors for calcium keep energy production smooth in the powerhouses of heart cells

September 18, 2018
Stress demands the heart to work harder and faster. To keep pace, the muscle must make its fuel at an accelerated rate. Bursts of calcium entering mitochondria—the cell's powerhouses—normally help control energy output, ...

First gut bacteria may have lasting effect on ability to fight chronic diseases

September 18, 2018
New research showing that the first bacteria introduced into the gut have a lasting impact may one day allow science to adjust microbiomes—the one-of-a-kind microbial communities that live in our gastrointestinal tracts—to ...

A new defender for your sense of smell

September 18, 2018
New research from the Monell Center increases understanding of a mysterious sensory cell located in the olfactory epithelium, the patch of nasal tissue that contains odor-detecting olfactory receptor cells. The findings suggest ...

Small molecule plays big role in weaker bones as we age

September 18, 2018
With age, expression of a small molecule that can silence others goes way up while a key signaling molecule that helps stem cells make healthy bone goes down, scientists report.

Sperm quality study updates advice for couples trying to conceive

September 17, 2018
Could doctors at fertility clinics be giving men bad advice? Dr. Da Li and Dr. XiuXia Wang, who are clinician-researchers at the Center for Reproductive Medicine of Shengjing Hospital in Shenyang in northeast China, think ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.