by Mikael Wikgren, Thomas Karlsson, Johanna Lind, Therese Nilbrink, Johan Hultdin, Kristel Sleegers, Christine Van Broeckhoven, Göran Roos, Lars-Göran Nilsson, Lars Nyberg, Rolf Adolfsson, Karl-Fredrik Norrback
Telomere length shortens with cellular division, and leukocyte telomere length is used as a marker for systemic telomere length. The hippocampus hosts adult neurogenesis and is an important structure for episodic memory, and carriers of the apolipoprotein E e4 allele exhibit higher hippocampal atrophy rates and differing telomere dynamics compared with non-carriers. The authors investigated whether leukocyte telomere length was associated with hippocampal volume in 57 cognitively intact subjects (29 e3/e3 carriers; 28 e4 carriers) aged 49–79 yr. Leukocyte telomere length correlated inversely with left (rs?=?-0.465; p?=?0.011), right (rs?=?-0.414; p?=?0.025), and total hippocampus volume (rs?=?-0.519; p?=?0.004) among APOE e3/e3 carriers, but not among e4 carriers. However, the e4 carriers fit with the general correlation pattern exhibited by the e3/e3 carriers, as e4 carriers on average had longer telomeres and smaller hippocampi compared with e3/e3 carriers. The relationship observed can be interpreted as long telomeres representing a history of relatively low cellular proliferation, reflected in smaller hippocampal volumes. The results support the potential of leukocyte telomere length being used as a biomarker for tapping functional and structural processes of the aging brain.