Yaron Hamani

MiRNA-Mediated Control of HLA-G Expression and Function

HLA-G is a non-classical HLA class-Ib molecule expressed mainly by the extravillous cytotrophoblasts (EVT) of the placenta. The expression of HLA-G on these fetal cells protects the EVT cells from immune rejection and is therefore important for a healthy pregnancy. The mechanisms controlling HLA-G expression are largely unknown. Here we demonstrate that miR-148a and miR-152 down-regulate HLA-G expression by binding its 3′UTR and that this down-regulation of HLA-G affects LILRB1 recognition and consequently, abolishes the LILRB1-mediated inhibition of NK cell killing. We further demonstrate that the C/G polymorphism at position +3142 of HLA-G 3′UTR has no effect on the miRNA targeting of HLA-G. We show that in the placenta both miR-148a and miR-152 miRNAs are expressed at relatively low levels, compared to other healthy tissues, and that the mRNA levels of HLA-G are particularly high and we therefore suggest that this might enable the tissue specific expression of HLA-G.

Inhibitory NK receptor recognition of HLA-G: regulation by contact residues and by cell specific expression at the fetal-maternal interface.

The non-classical HLA-G protein is distinguished from the classical MHC class I molecules by its expression pattern, low polymorphism and its ability to form complexes on the cell surface. The special role of HLA-G in the maternal-fetal interface has been attributed to its ability to interact with specific receptors found on maternal immune cells. However this interaction is restricted to a limited number of receptors. In this study we elucidate the reason for this phenomenon by comparing the specific contact residues responsible for MHC-KIR interactions. This alignment revealed a marked difference between the HLA-G molecule and other MHC class I molecules. By mutating these residues to the equivalent classical MHC residues, the HLA-G molecule regained an ability of interacting with KIR inhibitory receptors found on NK cells derived either from peripheral blood or from the decidua. Functional NK killing assays further substantiated the binding results. Furthermore, double immunofluorescent staining of placental sections revealed that while the conformed form of HLA-G was expressed in all extravillous trophoblasts, the free heavy chain form of HLA-G was expressed in more distal cells of the column, the invasion front. Overall we suggest that HLA-G protein evolved to interact with only some of the NK inhibitory receptors thus allowing a control of inhibition, while permitting appropriate NK cell cytokine and growth factor production necessary for a viable maternal fetal interface.

The natural course of endometrial polyps: Could they vanish when left untreated?

OBJECTIVE To report the occurrence of spontaneous regression of three endometrial polyps detected by hysteroscopy. DESIGN Case series. SETTING A uterine imaging unit in an academic medical center. PATIENT(S) Three patients diagnosed as having an endometrial polyp of 5-8 mm on hysteroscopy. INTERVENTION(S) Patient deferral of the surgical procedure for several months. MAIN OUTCOME MEASURE(S) Presence of a uterine polyp in the next hysteroscopy. RESULT(S) The polyps disappeared spontaneously. CONCLUSION(S) Deferral of hysteroscopic polypectomy for a few months in asymptomatic women in the hope of spontaneous regression of the polyps may be justified.

The significance of intrauterine lesions detected by ultrasound in asymptomatic postmenopausal patients

A retrospective study on 82 women with an incidental sonographic finding suspected to be intrauterine polyps was undertaken to assess the histopathologic characteristics of such polyps utilising operative hysteroscopy. Endometrial polyps were found in 68 patients, submucousal myomas in 7, atrophic endometrium in 6 and thickened proliferative endometrium was found in 1 patient. Simple hyperplasia was found in one polyp but neither endometrial carcinoma nor complex hyperplasia was found. The total complication rate was 3.6%. It appears that the risk of endometrial carcinoma in postmenopausal women with asymptomatic endometrial polyps is low, although a larger series is required to confirm this finding.

The incidence and haemodynamic significance of gas emboli during operative hysteroscopy: a prospective echocardiographic study

AIMS Operative hysteroscopy is associated with complications including the development of gas embolism. The aim of this study was to utilize continuous echocardiographic imaging during operative hysteroscopy to assess the extent and the haemodynamic effects of gas embolism in these patients. METHODS AND RESULTS Women undergoing operative hysteroscopy under general anaesthesia without a history of cardiac disease were eligible. Transthoracic echocardiography (TTE) was performed continuously in all study participants with assessment of the extent and frequency of gas embolism, right ventricular function and pulmonary hypertension. Twenty-three women (mean age: 48.0 +/- 9.4 years) participated in the study. All subjects had evidence of bubble embolism in the right atrium (RA) and 20 of 23 (85%) had evidence of continuous flow of bubbles. In the 17 patients with adequate assessment, estimated pulmonary artery systolic pressure was 19.1 +/- 3.7 mmHg prior to the procedure and 23.3 +/- 3.4 following the procedure, a statistically significant difference (P < 0.05). There were no significant changes between the two groups in right ventricular end-diastolic area, end-systolic area, or fractional area change. CONCLUSION Our study demonstrates a high frequency of continuous gas embolism during hysteroscopy, which is associated with a small but statistically significant increase in pulmonary artery systolic pressure without affecting right ventricular function.

Intrauterine balloon tamponade as a treatment for immune thrombocytopenic purpura-induced severe uterine bleeding

OBJECTIVE To report our experience of applying balloon tamponade in the treatment of intrauterine bleeding in two patients with immune thrombocytopenic purpura (ITP). Immune thrombocytopenic purpura is a well-known hematologic autoimmune disease. The uterus may be a major site of bleeding in patients with ITP. Halting bleeding is imperative to reduce blood loss and platelet consumption and to allow medical treatment to increase platelet count. Balloon tamponade has been described as an effective method to control bleeding in a variety of clinical situations; it is an effective and accessible modality, requiring no analgesia or anesthesia, and helps facilitate continuous monitoring of uterine bleeding. DESIGN Report of two cases. SETTING Obstetrics and gynecology department in a tertiary care center in Jerusalem, Israel. PATIENT(S) Two patients with ITP with severe uterine bleeding refractory to treatment with estrogen and IV IgG. INTERVENTION(S) Intrauterine balloon tamponade. MAIN OUTCOME MEASURE(S) Cessation of uterine bleeding, appearance of complications. RESULT(S) Insertion of balloon tamponade successfully controlled bleeding in both cases. The patient in case 1 subsequently had persistent hypomenorrhea. The patient in case 2 had abdominal pain and suspected pelvic inflammation. CONCLUSION(S) Our presented cases demonstrate that uterine bleeding can be controlled successfully in patients with ITP with an intrauterine balloon. This novel application raises many technical issues, such as the appropriate filling pressures and duration of treatment. Possible risks, such as endometrial injury, still remain to be resolved and mandate future clinical research.

Human trophectoderm apposition is regulated by interferon γ-induced protein 10 (IP-10) during early implantation.

INTRODUCTION The first step in human implantation is the attraction of the blastocyst to the endometrium. We aimed to study attraction of the human blastocyst to the endometrium, and how this process is accomplished by chemokines secreted by the endometrium. MATERIALS AND METHODS Blastocyst trophectoderm cells and other trophoblast lineage cells were subjected to attraction assays by IP-10 and other chemokines using transwell migration and chemotaxis assays. Chemokine expression and secretion were investigated using immunohistochemistry, ELISA, FACS analysis, and RT-PCR on material from flushing of the uterine cavity in endometrial biopsies. Chemokine receptor expression by blastocyst trophectoderm following PGD biopsy, trophectoderm derived from hES, placental villi, and other trophoblast lineage cells were characterized by the same methods. RESULTS IP-10 dramatically attracted trophectoderm derived from hES cells and other lineages by interaction with CXCR3 chemokine receptors, as shown by both chemotaxis and transwell migration. High levels of IP-10 were detected throughout the menstrual cycle at flushing of the uterine cavity. Immunohistochemistry, FACS analysis, and RT-PCR of endometrial biopsy detected IP-10 in glandular and stromal cells of the endometrium. High levels of IP-10 were detected in condition medium of the endometrial stromal and glandular cells. Of all of the chemokine/chemokine receptor combinations examined, the IP-10/CXCR3 interaction was the only cytokine that was significantly elevated. DISCUSSION While they await the wandering blastocyst, IP-10 is produced by many cells of the endometrium, but not by endometrial natural killer cells. CONCLUSION Endometrial IP-10 may specifically attract human blastocyst trophectoderm cells early in implantation.

The clinical significance of small endometrial polyps

OBJECTIVE Small endometrial polyps are relatively common in asymptomatic women and may regress spontaneously. In symptomatic women, the finding of a small polyp (<1cm diameter) raises the question of the clinical pertinence and necessity of excision. Sparse data are available on the effectiveness of hysteroscopic excision of small polyps to manage abnormal uterine bleeding. The aim of this study was to assess outcome after hysteroscopic excision of small endometrial polyps in symptomatic patients. STUDY DESIGN This was an observational cohort study enrolling 255 premenopausal women presenting with abnormal uterine bleeding and a small endometrial polyp on office hysteroscopy, undertaken between January 2004 and February 2007. The study group was referred for polypectomy by operative hysteroscopy. The outcome of the procedure was reviewed 6-12 months later by a telephone interview to assess the pattern of uterine bleeding after the procedure and overall satisfaction. RESULTS Significant improvement in the magnitude of bleeding was experienced by 70% of participants, but only 30% of them reported return to regular menses. Satisfaction with the procedure was reported by 80%. Younger patients reported a less favorable bleeding pattern and were found to be less satisfied with the outcome of the procedure. CONCLUSIONS Symptomatic women with small endometrial polyps can be treated safely and efficiently with hysteroscopic excision. In the younger age group of patients, however, the outcome of the procedure may be less favorable and may necessitate the addition of endometrial ablation to improve outcome and increase patient satisfaction.

Hysterohydrosonoscopy—an integrated modality for uterine imaging

Office hysteroscopy and hydrosonography have long been viewed as competitive methods. This study was aimed to find out whether a combined approach of hysteroscopy followed by hydrosonography could provide more accurate information about the uterine lumen. Consecutive patients referred for diagnostic hysteroscopy were recruited to the study. Each patient had a transvaginal ultrasound scan, hysteroscopy, and immediately thereafter hydrosonography. Additional information retrieved by hydrosonography was recorded. When hysteroscopy revealed a normal uterine cavity, no further information was gained from hydrosonography. However, in 80% of the cases where hysteroscopy showed an abnormal uterine cavity (e.g., septum, adhesions, fibroid, endometrial polyp), hydrosonography added significant information regarding the size of the lesion, degree of fibroid encroachment, or luminal contour. We conclude that a combination of diagnostic hysteroscopy and hydrosonography could serve as a simple “one-stop” approach for full evaluation of the uterine cavity.