Keimzelltransplantation als Methode zur Fertilitätserhaltung bei onkologischen Patienten

Zusammenfassung.

Spermatogonien sind die diploiden Stammzellen der Spermatogenese. Sie übernehmen die Aufgaben der Selbsterhaltung von undifferenzierten Stammzellen und der Produktion von differenzierenden diploiden Keimzellen, die in den Prozess der Spermatogenese eintreten und letztendlich als Spermien den Hoden verlassen. Spermatogonien weisen zahlreiche Ähnlichkeiten mit anderen Stammzellen auf, es gibt aber auch einige physiologische Besonderheiten. Viele Fragen zur Kinetik der Spermatogonienteilung, der hormonellen Regulation von Proliferation und Differenzierung und der klinischen Relevanz von Spermatogonien für testikuläre Funktionsstörungen sind noch nicht ausreichend untersucht. Die Zerstörung der Spermatogonien durch Zytostatika oder Bestrahlung, die zur temporären oder permanenten Unfruchtbarkeit des Patienten führt, ist jedoch eine häufige, unerwünschte Begleiterscheinung onkologischer Therapien. Die Entnahme und extrakorporale Aufbewahrung testikulärer Stammzellen mit anschließender Retransplantation in den Hoden könnte in Zukunft als Therapie zur Erhaltung der Fertilität bei onkologischen Erkrankungen Anwendung finden.

Spermatogonia are the diploid cells in the testis, representing a small self-sustaining pool of male germ line stem cells as well as a larger pool of differentiating germ cells which enter the process of spermatogenesis. After going through prophase of meiosis as spermatocytes these cells finally leave the testis as sperm. Spermatogonia share many characteristics with other stem cells but also carry some specific physiological features. Many details about the kinetics of spermatogonial divisions, about the hormonal regulation of their expansion and differentiation and about their clinically relevant involvement as a cause for male infertility are poorly understood. However, the loss of spermatogonia following chemo- or radiotherapy leading to temporary or permanent infertility of the patient is a well known and unwanted site effect of many oncological therapies. Isolation and extracorporal storage of spermatogonia prior to the treatment and transplantation into the testis after recovery from the disease presents a promising future tool for fertility preservation in male patients undergoing oncological therapy.

Schlüsselwörter

Infertilität - Tumortherapie - Spermatogenese - Stammzellen

Key words

Infertility - tumour therapy - spermatogonia - stem cell - testis

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