Mechanism of pancreatic beta cell expansion by bone marrow transplantation

骨髓移植增加β细胞数量，但其潜在机制尚未阐明。在这项研究中，我们研究了它的机制。在几种条件下的骨髓移植实验表明，全身照射而不注射骨髓细胞可以增加β细胞群。另一方面，仅照射骨髓或仅照射胰腺不能增加β细胞质量。此外，使用β细胞特异性VEGF-A敲除小鼠，我们发现β细胞中的VEGF-A表达对于骨髓移植增加β细胞质量是必不可少的。因此，全身照射对于骨髓移植诱导的β细胞质量的增加是必要的和足够的，并且β细胞中的VEGF-A对于这种现象也是必要的。

Bone marrow transplantation increases beta cell mass, however its underlying mechanism has not been elucidated yet. In this study, we investigated its mechanism. Bone marrow transplantation experiments under several conditions revealed that systemic irradiation without injection of bone marrow cells can increase beta cell mass. On the other hand, irradiation only to bone marrow or only to pancreas cannot increase beta cell mass. In addition, using beta cell specific VEGF-A knock out mice, we found that VEGF-A expression in beta cells are essential for the increase in beta cell mass by bone marrow transplantation. Accordingly, systemic irradiation is essential and sufficient for bone marrow transplantation induced increase in beta cell mass and VEGF-A in beta cells are also essential for this phenomenon.