The Role of Uterine Natural Killer Cells on Recurrent Miscarriage and Recurrent Implantation Failure: From Pathophysiology to Treatment.

Uterine natural killer (uNK) cells constitute a unique uterine leucocyte subpopulation facilitating implantation and maintaining pregnancy. Herein, we critically analyze current evidence regarding the role of uNK cells in the events entailed in recurrent implantation failure (RIF) and recurrent miscarriages (RM). Data suggest an association between RIF and RM with abnormally elevated uNK cells' numbers, as well as with a defective biological activity leading to cytotoxicity. However, other studies do not concur on these associations. Robust data suggesting a definitive causative relationship between uNK cells and RIF and RM is missing. Considering the possibility of uNK cells involvement on RIF and RM pathophysiology, possible treatments including glucocorticoids, intralipids, and intravenous immunoglobulin administration have been proposed towards addressing uNK related RIF and RM. When considering clinical routine practice, this study indicated that solid evidence is required to report on efficiency and safety of these treatments as there are recommendations that clearly advise against their employment. In conclusion, defining a causative relationship between uNK and RIF-RM pathologies certainly merits investigation. Future studies should serve as a prerequisite prior to proposing the use of uNK as a biomarker or prior to targeting uNK cells for therapeutic purposes addressing RIF and RM.

Autologous Platelet-Rich Plasma Treatment Enables Pregnancy for a Woman in Premature Menopause.

This report presents the case of a woman aged 40 who has experienced premature menopause from the age of 35. Having rejected oocyte donation, she opted for intraovarian injection of autologous platelet-rich plasma with the aim to rejuvenate the ovarian tissue and enable the employment of her own gametes through in-vitro fertilization. Six weeks following the autologous platelet-rich plasma treatment, a significant reduction in the patient's follicle-stimulating hormone (FSH) levels were noted. A natural in-vitro fertilization cycle led to a biochemical pregnancy, resulting in a spontaneous abortion at the 5th week of pregnancy. This is the first report of a successful autologous platelet-rich plasma application leading to pregnancy in menopause. This report uniquely contributes to the medical knowledge and challenges current practice in the context of infertility. The efficiency and safety of this treatment with regard to the reproductive system merits further investigation.