一个国际研究小组日前发现，一旦胰腺中生成胰岛素的胰岛β细胞全被破坏，那么胰腺中就会有其他细胞出来“救急”，“变身”为胰岛β细胞。这一发现表明，胰岛β细胞可以“再生”，这也许有助于医学专家重新设计对糖尿病的疗法。
一般而言，胰腺中的胰岛α细胞负责制造胰高血糖素，胰岛β细胞负责制造胰岛素。但日本奈良尖端科学技术大学院大学和瑞士日内瓦大学研究人员通过小鼠实验表明，这种分工并不是不可改变的。
研究人员给小鼠使用了一种名为白喉的毒素，将小鼠体内的胰岛β细胞全部破坏，结果小鼠出现糖尿病症状。为了维持小鼠的生命，研究人员给它们注射胰岛素。两到四周后，他们惊讶地发现，小鼠体内的胰岛α细胞出现变化，原本只负责制造胰高血糖素的胰岛α细胞现在开始制造新的胰岛β细胞。
在接受实验的8只小鼠中，有一半在10个月以后胰岛β细胞增殖到原有数量的20％左右，摆脱了糖尿病症状。
此前，研究人员从未发现胰岛α细胞能够成为胰岛β细胞的来源。他们指出，如果人体内胰岛α细胞能够代替数目减少或者功能减弱的胰岛β细胞，将会为糖尿病治疗带来希望。这一研究成果刊登在最新一期英国《自然》杂志网络版上。
生物谷推荐原文出处：
Nature doi:10.1038/nature08894
Conversion of adult pancreatic α-cells to β-cells after extreme β-cell loss
Fabrizio Thorel1,3, Virginie Népote1,3, Isabelle Avril1,3, Kenji Kohno2, Renaud Desgraz1, Simona Chera1 " Pedro L. Herrera1
Department of Cell Physiology " Metabolism, University of Geneva Faculty of Medicine, 1 rue Michel-Servet, CH-1211 Geneva 4, Switzerland
Graduate School of Biological Sciences, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
These authors contributed equally to this work.
Pancreatic insulin-producing β-cells have a long lifespan, such that in healthy conditions they replicate little during a lifetime. Nevertheless, they show increased self-duplication after increased metabolic demand or after injury (that is, β-cell loss). It is not known whether adult mammals can differentiate (regenerate) new β-cells after extreme, total β-cell loss, as in diabetes. This would indicate differentiation from precursors or another heterologous (non-β-cell) source. Here we show β-cell regeneration in a transgenic model of diphtheria-toxin-induced acute selective near-total β-cell ablation. If given insulin, the mice survived and showed β-cell mass augmentation with time. Lineage-tracing to label the glucagon-producing α-cells before β-cell ablation tracked large fractions of regenerated β-cells as deriving from α-cells, revealing a previously disregarded degree of pancreatic cell plasticity. Such inter-endocrine spontaneous adult cell conversion could be harnessed towards methods of producing β-cells for diabetes therapies, either in differentiation settings in vitro or in induced regeneration.
