Partially consumed are the specialized internal membranes mitochondria use to generate energy-rich compounds for the cell, making the mitochondrial strategy appear to create more problems than it might solve. Nevertheless, the response appears to help maintain healthy heart function throughout caloric restriction.
"It is likely that the changes in the membranes make the mitochondria more energy efficient and serve as an adaptation to nutritional deprivation in mammals," says Richard Gross, M.D., Ph.D., senior author and professor of medicine and director of the Division of Bioorganic Chemistry and Molecular Pharmacology in the Department of Medicine.
The findings, scheduled to be reported in an upcoming issue of the journal Biochemistry and now available through advance online publication, may have implications for human cardiovascular health.
In their studies of mouse heart muscle, the research team found levels of two members of a class of lipids (fatty molecules) called phospholipids fell dramatically when food was withheld. For one type of phospholipid, levels decreased by 20 percent after only four hours of fasting and for the other, levels dropped a remarkable 40 percent after twelve hours of fasting.
The changes in phospholipids occurred mainly in the mitochondria, which are highly abundant in heart muscle cells and account for most of the phospholipid content of the cells. Mitochondria serve to break down many types of fats to produce the high-energy cellular fuel ATP, which is essential for a multitude of cellular processes, including the regular contraction
Contact: Gwen Ericson
Washington University School of Medicine