Scientists Use Couch Potato Mouse Model to Understand Muscle Function

A couch potato mouse model has been used by scientists at Sanford-Burnham Medical Research Institute to study muscle function.

Daniel Kelly and his colleagues found that these mice maintain normal activity and body weight but do not have the energy to exercise.

Stem Cell Therapy Improves Muscle Function in Muscular Dystrophy
A treatment for muscular dystrophy may be within view after US scientists reported Sunday they used stem cell transplants to improve muscle function in mice afflicted with the disease.

They report what happens when muscle tissue lacks PGC-1, a protein coactivator that muscles need to convert fuel into energy.

In obese individuals, PGC-1 levels drop, possibly further reducing a person's capacity to exercise - creating a vicious cycle. In this study, mice without muscle PGC-1 looked normal and walked around without difficulty, but could not run on a treadmill.

What happens is that the part of the cell that converts fuel into energy - can't function properly, so cells have to work harder to stay vigorous. This extra effort rapidly depletes carbohydrate fuel stores, leading to premature fatigue.

Older Adults can Work on Fitness Levels With Dietary Supplement Beta-alanine
Scientists have found evidence that Beta-alanine (BA), a dietary supplement widely used by athletes and body builders, can boost fitness levels in older adults.

However, PGC-1-deficient couch potato mice were not obese and still respond normally to insulin - meaning they are not at risk for developing diabetes despite their sedentary lifestyles and mitochondrial problems.

This study dispels that notion, instead suggesting that perhaps malfunctioning mitochondria are a result of diabetes, rather than a cause.

Boffins Identify Gene Linked to Hereditary Incontinence
The culprit gene for a rare condition that turns smiles into grimaces and impedes bladder and bowel control has been identified by Medical College of Georgia researchers.

"Lo and behold, even though these animals couldn't run, they showed no evidence of insulin resistance," Kelly said.

"We are now investigating what happens when we boost PGC-1 activity intermittently, as normally occurs when a person exercises."

The study appears in the December 1 issue of Cell Metabolism.

Source-ANI