Duration of anorexia nervosa is positively associated with whole blood mitochondrial DNA copy number: A cross-sectional case-control study

Background and Objectives

Anorexia nervosa (AN) is associated with significant physical and psychological stress. Stress causes changes at a cellular level and mitochondria may reflect this stress via changes such as alterations in DNA quantity or in their function. Mitochondria are unique in that they possess their own DNA, distinct from nuclear DNA, of which there are many copies within the cell. An indirect measure of mitochondrial function is the assessment of mitochondrial DNA copy number (mtDNAcn). Telomere length (TL) represents a marker of normal biological ageing, and TL can be shortened by stressors. We sought to test the following hypotheses: (1) that increased mtDNAcn would be found in patients with AN in comparison to healthy controls, (2) that mtDNAcn is related to duration and severity of AN, and (3) mtDNAcn is correlated with TL.

Methods

Using quantitative real-time polymerase chain reaction, we calculated mtDNAcn and TL using peripheral whole blood DNA collected from patients with AN (n = 23) compared to samples from age- and sex-matched healthy controls (n = 33). Clinical characteristics were also obtained.

Results

We found no difference between mtDNAcn in patients with AN in comparison to controls. mtDNAcn was positively associated with duration of illness, but not with illness severity. There was no association between mtDNAcn and TL.

Conclusions

Further investigations may clarify whether compensatory mechanisms increase mtDNAcn with increased illness duration.