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Tempest N, Hill CJ, Maclean A, Marston K, Powell SG, Al-Lamee H, Hapangama DK. Novel microarchitecture of human endometrial glands: implications in endometrial regeneration and pathologies. Hum Reprod Update 2021; 28:153-171. [PMID: 34875046 PMCID: PMC8888994 DOI: 10.1093/humupd/dmab039] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/15/2021] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Human endometrium remains a poorly understood tissue of the female reproductive tract. The superficial endometrial functionalis, the site of embryo implantation, is repeatedly shed with menstruation, and the stem cell-rich deeper basalis is postulated to be responsible for the regeneration of the functionalis. Two recent manuscripts have demonstrated the 3D architecture of endometrial glands. These manuscripts have challenged and replaced the prevailing concept that these glands end in blind pouches in the basalis layer that contain stem cells in crypts, as in the intestinal mucosa, providing a new paradigm for endometrial glandular anatomy. This necessitates re-evaluation of the available evidence on human endometrial regeneration in both health and disease in the context of this previously unknown endometrial glandular arrangement. OBJECTIVE AND RATIONALE The aim of this review is to determine if the recently discovered glandular arrangement provides plausible explanations for previously unanswered questions related to human endometrial biology. Specifically, it will focus on re-appraising the theories related to endometrial regeneration, location of stem/progenitor cells and endometrial pathologies in the context of this recently unravelled endometrial glandular organization. SEARCH METHODS An extensive literature search was conducted from inception to April 2021 using multiple databases, including PubMed/Web of Science/EMBASE/Scopus, to select studies using keywords applied to endometrial glandular anatomy and regeneration, and the references included in selected publications were also screened. All relevant publications were included. OUTCOMES The human endometrial glands have a unique and complex architecture; branched basalis glands proceed in a horizontal course adjacent to the myometrium, as opposed to the non-branching, vertically coiled functionalis glands, which run parallel to each other as is observed in intestinal crypts. This complex network of mycelium-like, interconnected basalis glands is demonstrated to contain endometrial epithelial stem cells giving rise to single, non-branching functionalis glands. Several previous studies that have tried to confirm the existence of epithelial stem cells have used methodologies that prevent sampling of the stem cell-rich basalis. More recent findings have provided insight into the efficient regeneration of the human endometrium, which is preferentially evolved in humans and menstruating upper-order primates. WIDER IMPLICATIONS The unique physiological organization of the human endometrial glandular element, its relevance to stem cell activity and scarless endometrial regeneration will inform reproductive biologists and clinicians to direct their future research to determine disease-specific alterations in glandular anatomy in a variety of endometrial pathological conditions.
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Affiliation(s)
- Nicola Tempest
- Department of Women's and Children's Health, Centre for Women's Health Research, Institute of Life Course and Medical Sciences, University of Liverpool, Member of Liverpool Health Partners, Liverpool, UK.,Liverpool Women's NHS Foundation Trust, Member of Liverpool Health Partners, Liverpool, UK.,Hewitt Centre for Reproductive Medicine, Liverpool Women's NHS Foundation Trust, Liverpool, UK
| | - Christopher J Hill
- Department of Women's and Children's Health, Centre for Women's Health Research, Institute of Life Course and Medical Sciences, University of Liverpool, Member of Liverpool Health Partners, Liverpool, UK
| | - Alison Maclean
- Department of Women's and Children's Health, Centre for Women's Health Research, Institute of Life Course and Medical Sciences, University of Liverpool, Member of Liverpool Health Partners, Liverpool, UK.,Liverpool Women's NHS Foundation Trust, Member of Liverpool Health Partners, Liverpool, UK
| | - Kathleen Marston
- Department of Women's and Children's Health, Centre for Women's Health Research, Institute of Life Course and Medical Sciences, University of Liverpool, Member of Liverpool Health Partners, Liverpool, UK
| | - Simon G Powell
- Department of Women's and Children's Health, Centre for Women's Health Research, Institute of Life Course and Medical Sciences, University of Liverpool, Member of Liverpool Health Partners, Liverpool, UK
| | - Hannan Al-Lamee
- Department of Women's and Children's Health, Centre for Women's Health Research, Institute of Life Course and Medical Sciences, University of Liverpool, Member of Liverpool Health Partners, Liverpool, UK.,Liverpool Women's NHS Foundation Trust, Member of Liverpool Health Partners, Liverpool, UK.,Hewitt Centre for Reproductive Medicine, Liverpool Women's NHS Foundation Trust, Liverpool, UK
| | - Dharani K Hapangama
- Department of Women's and Children's Health, Centre for Women's Health Research, Institute of Life Course and Medical Sciences, University of Liverpool, Member of Liverpool Health Partners, Liverpool, UK.,Liverpool Women's NHS Foundation Trust, Member of Liverpool Health Partners, Liverpool, UK
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Tempest N, Jansen M, Baker AM, Hill CJ, Hale M, Magee D, Treanor D, Wright NA, Hapangama DK. Histological 3D reconstruction and in vivo lineage tracing of the human endometrium. J Pathol 2020; 251:440-451. [PMID: 32476144 DOI: 10.1002/path.5478] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 04/30/2020] [Accepted: 05/20/2020] [Indexed: 12/13/2022]
Abstract
Regular menstrual shedding and repair of the endometrial functionalis is unique to humans and higher-order primates. The current consensus postulates endometrial glands to have a single-tubular architecture, where multi-potential stem cells reside in the blind-ending glandular-bases. Utilising fixed samples from patients, we have studied the three-dimensional (3D) micro-architecture of the human endometrium. We demonstrate that some non-branching, single, vertical functionalis glands originate from a complex horizontally interconnecting network of basalis glands. The existence of a multipotent endometrial epithelial stem cell capable of regenerating the entire complement of glandular lineages was demonstrated by in vivo lineage tracing, using naturally occurring somatic mitochondrial DNA mutations as clonal markers. Vertical tracking of mutated clones showed that at least one stem-cell population resides in the basalis glands. These novel findings provide insight into the efficient and scar-less regenerative potential of the human endometrium. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Nicola Tempest
- Liverpool Women's Hospital NHS Foundation Trust, member of the Liverpool Health partnership, Liverpool, UK
- Department of Women's and Children's Health, Institute of Life Course and Medical Sciences, University of Liverpool, member of the Liverpool Health partnership, Liverpool, UK
| | - Marnix Jansen
- UCL Cancer Institute, University College London, London, UK
| | - Ann-Marie Baker
- Barts Cancer Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Christopher J Hill
- Department of Women's and Children's Health, Institute of Life Course and Medical Sciences, University of Liverpool, member of the Liverpool Health partnership, Liverpool, UK
| | - Mike Hale
- Pathology and Tumour Biology, University of Leeds, Leeds, UK
| | - Derek Magee
- School of Computing, University of Leeds, Leeds, UK
- Heterogenius Ltd, Leeds, UK
| | - Darren Treanor
- Pathology and Tumour Biology, University of Leeds, Leeds, UK
- Pathology department, Leeds Teaching Hospitals NHS Trust, Leeds, UK
- Pathology department, Linköping University, Linköping, Sweden
| | - Nicholas A Wright
- Barts Cancer Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Dharani K Hapangama
- Liverpool Women's Hospital NHS Foundation Trust, member of the Liverpool Health partnership, Liverpool, UK
- Department of Women's and Children's Health, Institute of Life Course and Medical Sciences, University of Liverpool, member of the Liverpool Health partnership, Liverpool, UK
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Endometrial Stem Cell Markers: Current Concepts and Unresolved Questions. Int J Mol Sci 2018; 19:ijms19103240. [PMID: 30347708 PMCID: PMC6214006 DOI: 10.3390/ijms19103240] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/07/2018] [Accepted: 10/10/2018] [Indexed: 02/07/2023] Open
Abstract
The human endometrium is a highly regenerative organ undergoing over 400 cycles of shedding and regeneration over a woman’s lifetime. Menstrual shedding and the subsequent repair of the functional layer of the endometrium is a process unique to humans and higher-order primates. This massive regenerative capacity is thought to have a stem cell basis, with human endometrial stromal stem cells having already been extensively studied. Studies on endometrial epithelial stem cells are sparse, and the current belief is that the endometrial epithelial stem cells reside in the terminal ends of the basalis glands at the endometrial/myometrial interface. Since almost all endometrial pathologies are thought to originate from aberrations in stem cells that regularly regenerate the functionalis layer, expansion of our current understanding of stem cells is necessary in order for curative treatment strategies to be developed. This review critically appraises the postulated markers in order to identify endometrial stem cells. It also examines the current evidence supporting the existence of epithelial stem cells in the human endometrium that are likely to be involved both in glandular regeneration and in the pathogenesis of endometrial proliferative diseases such as endometriosis and endometrial cancer.
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