Fertility in the Klinefelter syndrome by testicular stem cell transplantation - an experimantal approach in the XXY mice

通过睾丸干细胞移植治疗 Klinefelter 综合征的生育力——一种在 XXY 小鼠中进行的实验方法

• 批准号: 5454151
• 负责人: Dr. Joachim Wistuba
• 金额: --
• 依托单位: Abteilung für Klinische und Operative Andrologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5454151?language=en
• 关键词: Fertility; Klinefelter; syndrome; testicular; stem

The most common genetic cause of human male infertility is the Klinefelter syndrome (KS, 47,XXY) resulting in testicular failure, loss of germ cells and variable degrees of androgen deficiency paralleled by changes in gonadotropins. Although the KS is well known, it is not clear whether the loss of germ cells resulting in a Sertoli-cell-only (SCO) syndrome is due to a defect of the germ cell line, a disturbance of the testicular environment, or a combination of both. Many Klinefelter patients attend our Institute for infertility. Any possible therapeutic approaches to overcome this infertility requires findings from experimental work. The proposed project seeks to elucidate those prerequisites for therapeutic approaches to gain fertility in Klinefelter patients, e.g. by making use of autologous stem cells. Since at this stage such work cannot be performed in the patients themselves, the generation and use of an appropriate animal model is indespensable. Mice bearing a supernumerary X-chromosome (karyotype 41, XXY) mimicking the conditions found in patients have been generated by breeding animals with a spontaneously mutated Y-chromosome. We established a mouse colony of the strain B6Ei.Lt-Y to obtain 41 (XXY) male mice and determined the distinct karyotype of the living animals individually by fluorescence in situ hybridisation (FISH). We will show whether the testicular environment and the pituitary-gonadal axis in males bearing a supernumerary X-chromosome are able to support development of normal, diploid spermatogonial stem cells using our well-established methods of germ cell transplantation and grafting of testicular tissue. We will characterize aspects essential for male endocrinology and testicular function as in particular the Leydig cell function and maturation. Since some Klinefelter patients produce a small amount of sperm deriving from apparently normal diploid spermatogonia, the testicular environment should be able to support spermatogenesis. However, whether this would be possible in every patient or depends on the degree of mosaicism has not been clarified. Testicular sperm with a high rate of chromosomal abnormalities increase the abortion rate. Thus questions of disturbed testicular environment and an increased risk of aneuploidy have to be solved before any clinical transplantation approach can be offered. This problem will be addressed in the mouse model by examining sperm produced after germ cell transplantation and by performing ICSI followed by chromosomal analysis of embryos.

人类男性不育最常见的遗传原因是克兰费尔特综合征 (KS, 47,XXY)，导致睾丸衰竭、生殖细胞丧失和不同程度的雄激素缺乏，同时伴有促性腺激素的变化。尽管 KS 众所周知，但尚不清楚生殖细胞丢失导致的仅支持细胞 (SCO) 综合征是由于生殖细胞系缺陷、睾丸环境紊乱还是两者兼而有之两者都有。许多 Klinefelter 患者都来我们的不孕不育研究所就诊。任何克服这种不孕症的可能治疗方法都需要实验工作的结果。拟议的项目旨在阐明 Klinefelter 患者获得生育能力的治疗方法的先决条件，例如通过利用自体干细胞。由于现阶段此类工作无法在患者身上进行，因此合适的动物模型的产生和使用是必不可少的。带有多余 X 染色体（核型 41，XXY）的小鼠模仿患者体内发现的情况，是通过饲养带有自发突变 Y 染色体的动物而产生的。我们建立了B6Ei.Lt-Y品系的小鼠群体，获得了41只（XXY）雄性小鼠，并通过荧光原位杂交（FISH）分别确定了活体动物的独特核型。我们将使用我们完善的生殖细胞移植和睾丸组织移植方法，展示携带多余 X 染色体的男性的睾丸环境和垂体-性腺轴是否能够支持正常二倍体精原干细胞的发育。我们将描述男性内分泌和睾丸功能所必需的方面，特别是间质细胞的功能和成熟。由于一些 Klinefelter 患者会产生少量来自明显正常的二倍体精原细胞的精子，因此睾丸环境应该能够支持精子发生。然而，这是否适用于每个患者或取决于嵌合体的程度尚未明确。睾丸精子染色体异常率高会增加流产率。因此，在提供任何临床移植方法之前，必须解决睾丸环境紊乱和非整倍体风险增加的问题。这个问题将在小鼠模型中得到解决，方法是检查生殖细胞移植后产生的精子，并进行 ICSI，然后对胚胎进行染色体分析。