Endometriyal Reseptivitenin İmplantasyondaki Rolü

Öz

AbstractThe Role of Endometrial Receptivity in Implantation Blastocyst implantation is a dynamic process. This process involves embryo apposition and attachment to the prepared endometrial epithelium, and invasion into the endometrial stroma. Successful implantation is the result of reciprocal interactions between the blastocyst and receptive endometrium. The endometrium undergoes precisely defined morphological changes until receptive endometrium is developed. Endometrial receptivity represents a crucial limit for the success of in vitro fertilization and embryo transfer treatments. In other words a lack of synchrony between the embryo development and endometrial maturation results in an implantation failure. Blastocyst may implant only in the receptive phase, which is characterized by unique morphological and molecular changes of the endometrium. During implantation, the apical membranes of the epithelial cells lining the uterine cavity lose their microvilli and develop large and smooth membrane projections. These projections on the endometrial surface have been suggested as ultrastructural markers of the implantation window, which are known as pinopodes. Reduced implantation rates in IVF cycles could result from impaired or premature endometrial maturation, which could be accompanied by alterations in pinopode expression. Furthermore, maternal endometrial cells are regulated directly by ovarian steroids and indirectly by various growth factors and cytokines. Endometrial differentiation to support blastocyst implantation is coordinated by progesterone and oestrogen. Nevertheless, the molecular mechanisms that render the endometrium receptive to blastocyst implantation are not fully understood. Further research in this field may offer new therapeutic opportunities.

Anahtar Kelimeler

• implantation, endometrial receptivity, pinopod

Endometriyal Reseptivitenin İmplantasyondaki Rolü

Öz

Blastosist implantasyonu dinamik bir süreçtir. Bu süreç, embriyonun hazırlanmış endometriyum epiteline yaklaşmasını, tutunmasını ve endometriyal stromaya yayılmasını içerir. Başarılı bir implantasyon, blastosist ve reseptif endometriyum arasında karşılıklı etkileşimlerin sonucudur. Endometriyum, reseptif olana kadar belirli morfolojik değişiklikler geçirerek gelişir. Endometriyal reseptivite, in vitro fertilizasyon ve embriyo transferi tedavilerinin başarısında önemli bir sınırlama oluşturur. Diğer bir deyişle, embriyo gelişimi ve endometriyal olgunlaşma arasındaki bir uyum eksikliği, implantasyon başarısızlığının bir sebebidir. Blastosist sadece, endometriyumun benzersiz morfolojik ve moleküler değişiklikleriyle karakterize olan reseptif fazında implante olabilir. İmplantasyon boyunca, uterin boşluğa uzanan epitelyal hücrelerin apikal membranları mikrovillüslerini kaybeder, geniş ve düz membran uzantıları gelişir. Endometriyal yüzeydeki bu uzantılar implantasyon penceresinin ince yapı belirteçleri olarak tanımlanmıştır ve pinopodlar olarak bilinirler. Pinopod ekspresyonlarında değişimlerin eşlik edebildiği, bozulmuş veya prematür endometriyal olgunlaşma, IVF siklüslerinde implantasyon oranlarında azalmaya sebep olabilir. Dahası, maternal endometriyal hücreler; direk olarak ovaryan steroidlerle, indirek olarak çeşitli büyüme faktörleri ve sitokinlerle düzenlenirler. Blastosist implantasyonunu destekleyen endometriyum farklılaşması, progesteron ve östrojen tarafından ayarlanır. Yine de, blastosist implantasyonunda, endometriyum reseptivitesini sağlayan bu moleküler mekanizmalar tam olarak anlaşılmış değildir. Bu alandaki ileri çalışmalar yeni iyileştirici fırsatlar sunabilir.

Anahtar Kelimeler

• implantasyon, endometriyal reseptivite, pinopod

Kaynakça

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