Department of Molecular and Cellular Anatomy, University of Regensburg, Germany.
Adv Drug Deliv Rev. 2010 Jun 15;62(7-8):841-54. doi: 10.1016/j.addr.2010.01.004. Epub 2010 Feb 1.
In regenerative medicine much attention is given to stem/progenitor cells for a future therapy of acute and chronic renal failure. However, up to date sound cell biological knowledge about nephron renewal in kidney is lacking. For that reason molecular mechanisms are under intense investigation leading from stem/progenitor cells to regenerated tubules. In this coherence new biomaterials and drug delivery systems have to be elaborated showing an intense stimulation on the renewal of parenchyma. To analyze tubule regeneration a powerful culture system is of fundamental importance. An advanced technique stimulates renal stem/progenitor cells to develop numerous tubules between layers of a polyester fleece. Use of chemically defined Iscove's Modified Dulbecco's Medium (IMDM) containing aldosterone (1x10(-7)M) results in spatial development of renal tubules within 13 days of perfusion culture. Immunohistochemistry exhibits that numerous features of a polarized epithelium are expressed in generated tubules. Transmission electron microscopy (TEM) illuminates that generated tubules contain a polarized epithelium with a tight junctional complex and an intact basal lamina at the basal aspect. Development of tubules depends on applied aldosterone concentration and cannot be mimicked by precursors of its synthesis pathway or by other steroid hormones. Antagonists such as spironolactone or canrenoate prevent the development of tubules. This result illuminates that the tubulogenic development is mediated via the mineralocorticoid receptor (MR). Application of geldanamycin, radicicol, quercetin or KNK 437 in combination with aldosterone blocks development of tubules by disturbing the contact between MR and heat shock proteins 90 and 70. In conclusion, for the first time generation of renal tubules can be simulated under controlled in-vitro conditions. Using this model the effect of numerous innovative biomaterials and drug delivery system can be critically analyzed.
在再生医学中，人们非常关注干细胞/祖细胞，以期未来能够治疗急性和慢性肾衰竭。然而，迄今为止，人们对肾脏中肾单位的更新缺乏充分的细胞生物学知识。因此，人们正在深入研究从干细胞/祖细胞到再生小管的分子机制。在这方面，新的生物材料和药物输送系统必须得到精心设计，以强烈刺激实质的更新。为了分析小管的再生，强大的培养系统至关重要。一种先进的技术刺激肾干细胞/祖细胞在聚酯纤维的层之间发育出许多小管。使用含有醛固酮（1x10(-7)M）的化学定义的 Iscove 改良 Dulbecco 培养基（IMDM）可在灌注培养的 13 天内促进肾小管的空间发育。免疫组织化学显示，在生成的小管中表达了许多极化上皮的特征。透射电子显微镜（TEM）表明生成的小管包含具有紧密连接复合体和完整基底膜的极化上皮，基底膜位于基底侧。小管的发育取决于所施加的醛固酮浓度，不能被其合成途径的前体或其他甾体激素模拟。拮抗剂，如螺内酯或坎利酮，可阻止小管的发育。这一结果表明，小管发生的发育是通过盐皮质激素受体（MR）介导的。应用格尔德霉素、雷帕霉素、槲皮素或 KNK437 与醛固酮联合应用可通过干扰 MR 与热休克蛋白 90 和 70 之间的接触来阻止小管的发育。总之，首次可以在受控的体外条件下模拟肾小管的生成。使用该模型，可以对大量创新的生物材料和药物输送系统的效果进行严格分析。
