Diabetes Research Center, Brussels Free University-VUB, Laarbeeklaan 103, 1090, Brussels, Belgium.
Diabetologia. 2010 Nov;53(11):2380-8. doi: 10.1007/s00125-010-1851-4. Epub 2010 Jul 20.
AIMS/HYPOTHESIS: Neogenesis of beta cells and their clustering to small aggregates is a key process in prenatal development of beta cell mass. We investigated the contribution of postnatally formed small aggregates to functional beta cell mass in adult rats.
Conditions were defined for (1) counting total beta cell number in pancreases with relative error of <10% and (2) determining their distribution over aggregates of different size and over functionally different subpopulations.
Pancreases of 10-week-old male Wistar rats contained 2.8 ± 0.2 × 10⁶ beta cells, of which >90% was generated postnatally, involving: (1) neo-formation of 30,000 aggregates with diameter <50 μm including single cells; and (2) growth of 5,500 aggregates to larger sizes, accounting for 90% of the increase in cell number, with number of growing aggregates in the tail 50% greater than elsewhere. At 10 weeks, 86% of aggregates were <50 μm; compared with aggregates >200 μm, their beta cells exhibited a higher basal insulin content that was also resistant to glibenclamide-induced degranulation. The pool of Ki67-positive beta cells was sixfold larger than at birth and distributed over all aggregate sizes.
CONCLUSIONS/INTERPRETATION: We describe a method for in situ counting of beta cell numbers and subpopulations with low relative error. In adult rats, >90% of beta cells and beta cell aggregates are formed after birth. Aggregates <50 μm are more than 100-fold more abundant than aggregates >200 μm, which are selected for isolated islet studies. Their topographic and functional properties contribute to the functional heterogeneity of the beta cell population; their growth to larger aggregates with characteristic beta cell functions may serve future metabolic needs.
目的/假设：β细胞的新生及其聚集形成小聚集体是β细胞数量在产前发育过程中的关键过程。我们研究了新生的小聚集体对成年大鼠功能性β细胞数量的贡献。
定义了（1）在胰腺中计数总β细胞数量，其相对误差<10%；（2）确定其在不同大小的聚集体和不同功能亚群中的分布的条件。
10 周龄雄性 Wistar 大鼠的胰腺含有 2.8±0.2×10⁶β细胞，其中>90%是在出生后形成的，包括：（1）新生 30,000 个直径<50μm的聚集体，包括单细胞；（2）5,500 个聚集体生长到较大的尺寸，占细胞数量增加的 90%，尾部的生长聚集体数量比其他部位多 50%。在 10 周时，86%的聚集体<50μm；与>200μm的聚集体相比，其β细胞具有更高的基础胰岛素含量，对格列本脲诱导的脱颗粒也具有抗性。Ki67 阳性β细胞的池是出生时的六倍，并分布在所有聚集体大小上。
结论/解释：我们描述了一种用于原位计数β细胞数量和亚群的方法，其相对误差较低。在成年大鼠中，>90%的β细胞和β细胞聚集体是在出生后形成的。<50μm的聚集体比>200μm的聚集体多 100 多倍，后者更适合用于分离胰岛研究。它们的拓扑和功能特性有助于β细胞群体的功能异质性；它们生长到具有特征性β细胞功能的较大聚集体可能有助于未来的代谢需求。
