Telomere Shortening in Alzheimer's Disease Patients

Sporadic Alzheimer's Disease (AD) is considered an age-related disease, and telomere length has been shown to decrease with age in animal and human studies. Shortening of telomere length has also been reported to beis associated with numerous neurodegenerative diseases, including AD. The aim of this study is to confirm and further elucidate the relationship between peripheral telomere length and Alzheimer's disease, cognitive function, and duration of Alzheimer's disease.

In this study, we recruited 165 Han Chinese subjects, consisting of 79 normal controls and 86 patients with AD without family history of AD or vascular dementia cases. We measured telomere length (T/S ratio) at baseline using quantitative PCR.

Our data showed that the negative correlation between telomere length and age become much stronger in AD patients (n=86, r=-0.382, p<0.001) compared to the control group (n=79, r=-0.024, p=0.833), presenting an estimated telomere loss rate of 0.003 T/S ratio/year (p<0.001). Moreover, we observed that the duration of AD is significantly negatively correlated with telomere length (n=86, r=-0.224, p=0.039), especially in female patients (n=43, r=-0.375, p=0.013) and ApoE4-noncarrier patients (n=52, r=-0.368, p=0.007). We also had some unexpected results, namely that in AD patients, higher Minimum Mental State Examination (MMSE) score were associated with shorter telomere length (n=76, r=-0.281, p=0.014).

This study revealed an accelerated rate of telomere shortening in AD, as well as strong influence of gender and ApoE status on telomere length in the context of this disease.