Changes of polarity in somatic stem cells upon aging or disease lead to a functional deterioration of stem cells and consequently loss of tissue homeostasis, likely due to changes in the mode (symmetry versus asymmetry) of stem cell divisions. Changes in polarity of epigenetic markers (or ‘epi-polarity’) in stem cells, which are linked to alterations in chromatin architecture, might explain how a decline in the frequency of epipolar stem cells can have a long-lasting impact on the function of especially aging stem cells. The drift in epipolarity might represent a novel therapeutic target to improve stem cell function upon aging or disease. Here we review basic biological principles of epigenetic polarity, with a special focus on epipolarity and aging of hematopoietic stem cells.

中文翻译：

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表观遗传极性的丧失是造血干细胞衰老的标志。

衰老或疾病时体细胞干细胞极性的变化会导致干细胞功能退化，从而导致组织稳态丧失，这可能是由于干细胞分裂模式（对称与不对称）的变化。与染色质结构改变有关的干细胞表观遗传标记极性（或“表观极性”）的变化可能解释了表极干细胞频率的下降如何对细胞功能产生长期影响。尤其是老化的干细胞。对极的漂移可能代表了一种新的治疗靶点，可在衰老或疾病时改善干细胞功能。在这里，我们回顾了表观遗传极性的基本生物学原理，特别关注造血干细胞的表极性和老化。