"There has been some skepticism as to whether obesity per se is a bona fide cancer risk factor, rather than the habits that fuel it, including a poor diet and a sedentary lifestyle," said Derek M. Huffman, Ph.D., postdoctoral fellow at the Institute for Aging Research at the Albert Einstein College of Medicine in Bronx, N.Y. "Although those other lifestyle choices play a role, this study unequivocally demonstrates that visceral adiposity is causally linked to intestinal cancer."
Prior research has shown that obesity markedly increases the likelihood of being diagnosed with and dying from many cancers. Huffman and colleagues sought to determine if removing visceral fat in mice genetically prone to developing colon cancer might prevent or lessen the development of these tumors.
They randomly assigned the mice to one of three groups. Mice in the first group underwent a sham surgery and were allowed to eat an unrestricted "buffet style" diet, for the entirety of the study, which resulted in these mice becoming obese. Those in the second group were also provided an unrestricted diet and became obese, but they had their visceral fat surgically removed at the outset of the study. Mice in the third group also underwent a sham surgery, but were provided only 60 percent of the calories consumed by the other mice in order to reduce their visceral fat by dieting.
"Our sham-operated obese mice had the most visceral fat, developed the greatest number of intestinal tumors, and had the worst overall survival," Huffman said. "However, mice that had less visceral fat, either by surgical removal or a calorie-restricted diet, had a reduction in the number of intestinal tumors. This was particularly remarkable in the case of our group where visceral fat was surgically removed, because these mice were still obese, they just had very little abdominal fat."
The researchers then subdivided the groups by gender. In female mice, the removal of visceral fat was significantly related to a reduction in intestinal tumors, but calorie restriction was not. In male mice, calorie restriction had a significant effect on intestinal tumors, but removal of visceral fat did not.
"This suggests that there are important gender differences in how adiposity and nutrients interact with the tumor environment," Huffman said. "In addition, the study emphasizes the need to promote strategies that reduce visceral fat in abdominally obese individuals."
Huffman noted that more studies are needed to definitively uncover the mechanisms behind the causality between visceral fat and intestinal cancer, to determine how abdominal obesity and nutrient availability act independently during the stages of tumor promotion and progression, and to determine how other strategies to promote weight loss, such as bariatric surgery, affect cancer risk.Follow the AACR on Twitter: @aacr
Jeremy Moore | EurekAlert!
Study tracks inner workings of the brain with new biosensor
16.08.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn
Foods of the future
15.08.2018 | Georg-August-Universität Göttingen
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences