{"doi":"10.1093/humrep/dead069","title":"Hormonal stimulation reduces numbers and impairs function of human uterine natural killer cells during implantation","abstract":"STUDY QUESTION: How does an altered maternal hormonal environment, such as that seen during superovulation with gonadotropins in ART, impact human uterine immune cell distribution and function during the window of implantation? SUMMARY ANSWER: Hormonal stimulation with gonadotropins alters abundance of maternal immune cells including uterine natural killer (uNK) cells and reduces uNK cell ability to promote extravillous trophoblast (EVT) invasion. WHAT IS KNOWN ALREADY: An altered maternal hormonal environment, seen following ART, can lead to increased risk for adverse perinatal outcomes associated with disordered placentation. Maternal immune cells play an essential role in invasion of EVTs, a process required for proper establishment of the placenta, and adverse perinatal outcomes have been associated with altered immune cell populations. How ART impacts maternal immune cells and whether this can in turn affect implantation and placentation in humans remain unknown. STUDY DESIGN, SIZE, DURATION: A prospective cohort study was carried out between 2018 and 2021 on 51 subjects: 20 from natural cycles 8 days after LH surge; and 31 from stimulated IVF cycles 7 days after egg retrieval. PARTICIPANTS/MATERIALS, SETTING, METHODS: Endometrial biopsies and peripheral blood samples were collected during the window of implantation in subjects with regular menstrual cycles or undergoing superovulation. Serum estradiol and progesterone levels were measured by chemiluminescent competitive immunoassay. Immune cell populations in blood and endometrium were analyzed using flow cytometry. uNK cells were purified using fluorescence-activated cell sorting and were subjected to RNA sequencing (RNA-seq). Functional changes in uNK cells due to hormonal stimulation were evaluated using the implantation-on-a-chip (IOC) device, a novel bioengineered platform using human primary cells that mimics early processes that occur during pregnancy in a physiologically relevant manner. Unpaired t-tests, one-way ANOVA, and pairwise multiple comparison tests were used to statistically evaluate differences. MAIN RESULTS AND THE ROLE OF CHANCE: Baseline characteristics were comparable for both groups. As expected, serum estradiol levels on the day of biopsy were significantly higher in stimulated (superovulated) patients (P = 0.0005). In the setting of superovulation, we found an endometrium-specific reduction in the density of bulk CD56+ uNK cells (P < 0.05), as well as in the uNK3 subpopulation (P = 0.025) specifically (CD103+ NK cells). In stimulated samples, we also found that the proportion of endometrial B cells was increased (P < 0.0001). Our findings were specific to the endometrium and not seen in peripheral blood. On the IOC device, uNK cells from naturally cycling secretory endometrium promote EVT invasion (P = 0.03). However, uNK cells from hormonally stimulated endometrium were unable to significantly promote EVT invasion, as measured by area of invasion, depth of invasion, and number of invaded EVTs by area. Bulk RNA-seq of sorted uNK cells from stimulated and unstimulated endometrium revealed changes in signaling pathways associated with immune cell trafficking/movement and inflammation. LIMITATIONS, REASONS FOR CAUTION: Patient numbers utilized for the study were low but were enough to identify significant overall population differences in select immune cell types. With additional power and deeper immune phenotyping, we may detect additional differences in immune cell composition of blood and endometrium in the setting of hormonal stimulation. Flow cytometry was performed on targeted immune cell populations that have shown involvement in early pregnancy. A more unbiased approach might identify changes in novel maternal immune cells not investigated in this study. We performed RNA-seq only on uNK cells, which demonstrated differences in gene expression. Ovarian stimulation may also impact gene expression and function of other subsets of immune cells,","journal":"Human Reproduction","year":2023,"id":326497,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":28,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9467,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":377367,"name":"Scott M. Gordon","orcid":"0000-0003-1028-1953","position":1,"is_corresponding":false},{"id":389166,"name":"Sneha Mani","orcid":"0000-0002-5784-041X","position":2,"is_corresponding":false},{"id":1045991,"name":"Anna Sokalska","orcid":null,"position":3,"is_corresponding":false},{"id":1045528,"name":"Jae Young Park","orcid":"0000-0002-6664-6846","position":4,"is_corresponding":false},{"id":524021,"name":"Suneeta Senapati","orcid":"0000-0002-8956-8342","position":5,"is_corresponding":false},{"id":489928,"name":"Dongeun Huh","orcid":"0000-0002-5718-6884","position":6,"is_corresponding":false},{"id":389168,"name":"Monica Mainigi","orcid":"0000-0003-3306-4791","position":7,"is_corresponding":false},{"id":583221,"name":"Jessica R. Kanter","orcid":"0000-0002-1206-2319","position":0,"is_corresponding":true}],"reference_count":65,"raw_metadata":null,"created_at":"2026-07-19T01:08:33.106703Z","pmid":"37075311","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}