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Heil BA, van Heule M, Thompson SK, Kearns TA, Beckers KF, Oberhaus EL, King G, Daels P, Dini P, Sones JL. Metagenomic characterization of the equine endometrial microbiome during anestrus. J Equine Vet Sci 2024; 140:105134. [PMID: 38909766 DOI: 10.1016/j.jevs.2024.105134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 05/17/2024] [Accepted: 06/16/2024] [Indexed: 06/25/2024]
Abstract
The equine uterus is highly interrogated during estrus prior to breeding and establishing pregnancy. Many studies in mares have been performed during estrus under the influence of high estrogen concentrations, including the equine estrual microbiome. To date, it is unknown how the uterine microbiome of the mare is influenced by cyclicity; while, the equine vaginal microbiome is stable throughout the estrous cycle. We hypothesized that differences would exist between the equine endometrial microbiome of mares in estrus and anestrus. The aim of this study was two-fold: to characterize the resident endometrial microbiome of healthy mares during anestrus and to compare this with estrus. Double-guarded endometrial swabs were taken from healthy mares during estrus (n = 16) and in the following non-breeding season during anestrus (n = 8). Microbial population was identified using 16S rRNA sequencing. Our results suggest that the equine uterine microbiome in estrus has a low diversity and low richness, while during anestrus, a higher diversity and higher richness were seen compared to estrus. Despite this difference, both the estrus and anestrus endometrial microbiome were dominated by Proteobacteria, Firmicutes, and Bacteroidota. The composition of the microbial community between anestrus and estrus was significantly different. This may be explained by the difference in the composition of the endometrial immune milieu based on the stage of the cycle. Further research investigating the function of the equine endometrial microbiome and dynamics changes within the uterine environment is required.
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Affiliation(s)
- B A Heil
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, 70803, USA; Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA, 99164, USA
| | - M van Heule
- Department of Population Health and Reproduction (PHR), School of Veterinary Medicine, UCDavis, Davis, CA, 95616, USA; Department of Morphology, Imaging, Orthopedics, Rehabilitation and Nutrition, Faculty of Veterinary Medicine, UGent, Merelbeke, 9820, Belgium
| | - S K Thompson
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - T A Kearns
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - K F Beckers
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - E L Oberhaus
- School of Animal Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - G King
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - P Daels
- Department of Morphology, Imaging, Orthopedics, Rehabilitation and Nutrition, Faculty of Veterinary Medicine, UGent, Merelbeke, 9820, Belgium
| | - P Dini
- Department of Population Health and Reproduction (PHR), School of Veterinary Medicine, UCDavis, Davis, CA, 95616, USA
| | - J L Sones
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, 70803, USA; Equine Reproduction Laboratory, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, 80521, USA.
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Muderspach ND, Troedsson MHT, Ferreira-Dias G, Agerholm JS, Christoffersen M. Distribution of degenerative changes in the equine endometrium as observed in a single versus two biopsies. Theriogenology 2024; 213:52-58. [PMID: 37797529 DOI: 10.1016/j.theriogenology.2023.09.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/22/2023] [Accepted: 09/24/2023] [Indexed: 10/07/2023]
Abstract
Equine endometrial degeneration is diagnosed by microscopy of an endometrial biopsy but it is uncertain if findings in a single biopsy represent the state of the entire endometrium. Previous studies have compared samples from multiple sites but conclusions are inconsistent. Further clarification is therefore needed. In this study, presence and characteristics of endometrial degeneration were compared in two full thickness specimens from the ventral base of both uterine horns, obtained post mortem from cyclic mares (n = 82). Hematoxylin and eosin-stained sections were blinded evaluated for periglandular fibrosis, glandular nests, dilated glands, glandular dilation, excessive lymphatic vessels, and lymphatic lacunae. Each section was also assigned to a modified Kenney and Doig categorization. Statistical analysis included multiple logistic regression models for fraction of mares with disagreement in the modified Kenney and Doig category and fraction of mares with disagreement for each parameter, multiple generalized linear regression models for fraction of parameters with disagreement, and equivalence tests for agreement of a cumulative score of degenerative parameters. Possible effect of age, mare type and estrous cycle stage were included in the analyses. For the Kenney and Doig categorization, 49% of the mares had good agreement, 46% had moderate agreement and 5% had poor agreement between the two biopsies. Disagreement in the Kenney and Doig categorization between the two biopsies increased with age (OR = 1.1, P = 0.009). Disagreement within each parameter ranged from 10% of mares (glandular nests), to 31% (periglandular fibroblasts) and 37% (lymphatic lacunae). Disagreement for changes in endometrial glands increased with age (OR = 1.15-1.16, P < 0.040). Several mares (33%) had disagreement in at least two parameters, and the number of parameters with disagreement increased with age (HR = 1.04, P = 0.010). When tested for equivalence, the cumulative scores for paired endometrial samples did not differ for mares younger than 18 years (P = 0.011). In conclusion, the degenerative changes were not uniformly distributed, revealed by a disagreement between paired endometrial samples for individual parameters and for the Kenney and Doig categorization, which increased with age. This suggests that conclusions based on a single biopsy, particularly in mares over 17 years of age, should be interpreted with caution, and evaluation of two biopsies should be considered.
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Affiliation(s)
- Natacha D Muderspach
- Reproduction and Obstetrics, Department of Veterinary Clinical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Mats H T Troedsson
- The Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, USA
| | - Graça Ferreira-Dias
- CIISA- Center for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal; Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), Lisbon, Portugal
| | - Jørgen S Agerholm
- Reproduction and Obstetrics, Department of Veterinary Clinical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette Christoffersen
- Reproduction and Obstetrics, Department of Veterinary Clinical Sciences, University of Copenhagen, Copenhagen, Denmark
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Parrilla Hernández S, Franck T, Munaut C, Feyereisen É, Piret J, Farnir F, Reigner F, Barrière P, Deleuze S. Characterization of Myeloperoxidase in the Healthy Equine Endometrium. Animals (Basel) 2023; 13:ani13030375. [PMID: 36766264 PMCID: PMC9913682 DOI: 10.3390/ani13030375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/18/2023] [Accepted: 01/18/2023] [Indexed: 01/24/2023] Open
Abstract
Myeloperoxidase (MPO), as a marker of neutrophil activation, has been associated with equine endometritis. However, in absence of inflammation, MPO is constantly detected in the uterine lumen of estrous mares. The aim of this study was to characterize MPO in the uterus of mares under physiological conditions as a first step to better understand the role of this enzyme in equine reproduction. Total and active MPO concentrations were determined, by ELISA and SIEFED assay, respectively, in low-volume lavages from mares in estrus (n = 26), diestrus (n = 18) and anestrus (n = 8) in absence of endometritis. Immunohistochemical analysis was performed on 21 endometrial biopsies randomly selected: estrus (n = 11), diestrus (n = 6) and anestrus (n = 4). MPO, although mostly enzymatically inactive, was present in highly variable concentrations in uterine lavages in all studied phases, with elevated concentrations in estrus and anestrus, while in diestrus, concentrations were much lower. Intracytoplasmic immunoexpression of MPO was detected in the endometrial epithelial cells, neutrophils and glandular secretions. Maximal expression was observed during estrus in mid and basal glands with a predominant intracytoplasmic apical reinforcement. In diestrus, immunopositive glands were sporadic. In anestrus, only the luminal epithelium showed residual MPO immunostaining. These results confirm a constant presence of MPO in the uterine lumen of mares in absence of inflammation, probably as part of the uterine mucosal immune system, and suggest that endometrial cells are a source of uterine MPO under physiological cyclic conditions.
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Affiliation(s)
- Sonia Parrilla Hernández
- Physiology of Reproduction, Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium
| | - Thierry Franck
- Center for Oxygen Research and development (CORD), University of Liège, 4000 Liège, Belgium
| | - Carine Munaut
- Laboratory of Tumor and Developmental Biology, GIGA-Cancer, University of Liège, 4000 Liège, Belgium
| | - Émilie Feyereisen
- Laboratory of Tumor and Developmental Biology, GIGA-Cancer, University of Liège, 4000 Liège, Belgium
| | - Joëlle Piret
- Department of Morphology and Pathology, Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium
| | - Frédéric Farnir
- Biostatistics and Bioinformatics Applied to Veterinary Sciences, Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium
| | | | | | - Stéfan Deleuze
- Physiology of Reproduction, Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium
- Equine and Companion Animal Reproduction, Veterinary Medicine Faculty, University of Liège, 4000 Liège, Belgium
- Correspondence:
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Schöniger S, Schoon HA. The Healthy and Diseased Equine Endometrium: A Review of Morphological Features and Molecular Analyses. Animals (Basel) 2020; 10:ani10040625. [PMID: 32260515 PMCID: PMC7222714 DOI: 10.3390/ani10040625] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 12/14/2022] Open
Abstract
Simple Summary Diseases of the endometrium are a frequent cause of subfertility in mares and have an economic impact on the horse breeding industry. These include periglandular fibrosis of endometrial glands (endometrosis), degenerative diseases of vessels (angiosis), inflammation (endometritis), as well as altered differentiation of endometrial glands. Some mares are susceptible towards persistent endometritis. The etiology and pathogenesis of endometrosis are still unclear. This review describes morphological hallmarks and molecular features associated with endometrial health and different types of diseases. The presented literature data reveal characteristic differences in the expression of several extra- and intracellular molecules between the healthy and diseased equine endometrium. Some of these molecules can be detected directly within the tissue and thus have the potential to serve as excellent diagnostic markers for the presence of endometrial diseases. The knowledge of disease-associated changes in cellular differentiation, secretory functions, and immune mechanisms will help to decipher pathogenesis and will contribute to the development of novel treatments. In addition, the quantification of molecular alterations may contribute to a fertility prognosis for an individual mare. Reproductive health increases the well-being of mares and reduces financial loss for the horse breeding industry. Abstract Mares are seasonally polyestric. The breeding season in spring and summer and the winter anestrus are flanked by transitional periods. Endometrial diseases are a frequent cause of subfertility and have an economic impact on the horse breeding industry. They include different forms of endometrosis, endometritis, glandular maldifferentiation, and angiosis. Except for suppurative endometritis, these are subclinical and can only be diagnosed by the microscopic examination of an endometrial biopsy. Endometrosis is characterized by periglandular fibrosis and nonsuppurative endometritis by stromal infiltration with lymphocytes and plasma cells. The pathogenesis of endometrosis and nonsuppurative endometritis is still undetermined. Some mares are predisposed to persistent endometritis; this has likely a multifactorial etiology. Glandular differentiation has to be interpreted under consideration of the season. The presence of endometrial diseases is associated with alterations in the expression of several intra- and extracellular molecular markers. Some of them may have potential to be used as diagnostic biomarkers for equine endometrial health and disease. The aim of this review is to provide an overview on pathomorphological findings of equine endometrial diseases, to outline data on analyses of cellular and molecular mechanisms, and to discuss the impact of these data on reproduction and treatment.
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Affiliation(s)
- Sandra Schöniger
- Targos Molecular Pathology GmbH, Germaniastrasse 7, 34119 Kassel, Germany
- Correspondence:
| | - Heinz-Adolf Schoon
- Institute of Veterinary Pathology, Faculty of Veterinary Medicine, Leipzig University, An den Tierkliniken 33, 04103 Leipzig, Germany;
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Expression of Toll-like receptors 2, 4 and 6 in equine endometrial epithelial cells: A comparative in situ and in vitro study. Res Vet Sci 2017; 112:34-41. [PMID: 28119161 DOI: 10.1016/j.rvsc.2017.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 12/09/2016] [Accepted: 01/11/2017] [Indexed: 01/28/2023]
Abstract
Endometrial epithelial cells form a luminal barrier and are exposed to pathogens and non-infectious antigens. Toll-like receptors (TLRs) mediate pathogen defenses and tissue homeostasis, but are also involved in the pathogenesis of inflammatory and fibrosing alterations. Endometrial diseases are important causes of subfertility in mares. The pathogenesis of some types of persistent inflammation and periglandular fibrosis (endometrosis) is unknown. The aim of this study was to compare by in situ and in vitro immunohistochemistry the expression of TLRs 2, 4 and 6 in equine endometrial epithelial cells. An epithelial immunostaining for TLRs 2, 4 and 6 was detected in 76%, 57% and 90% of tissue sections, respectively. Positive cells lined the luminal surface, glandular ducts, mid glands and/or basal glands. An immunoreaction for TLRs 2, 4 and 6 was observed in 100%, 33% and 94% of cell cultures, respectively. The immunosignal was located in the cytoplasm and/or nucleus of endometrial epithelial cells under in situ and in vitro conditions. Results indicate a complex regulation of the epithelial expression of TLR 2, 4 and 6 proteins. The examined cell culture has to be regarded as suitable in vitro model. This study provides the basis for comparative investigations into the impact of different stimuli on the cellular expression of TLRs 2, 4 and 6. These will assist to find out if TLRs are involved in the pathogenesis of endometrial diseases and may help to understand as to why some mares develop persistent endometritis.
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Bramer SA, Macedo A, Klein C. Hexokinase 2 drives glycogen accumulation in equine endometrium at day 12 of diestrus and pregnancy. Reprod Biol Endocrinol 2017; 15:4. [PMID: 28056994 PMCID: PMC5217302 DOI: 10.1186/s12958-016-0223-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/14/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Secretion of histotroph during the prolonged pre-implantation phase in mares is crucial to pregnancy maintenance, manifested as increased embryonic loss in mares with age-related endometrial degeneration. Glycogen content of uterine histotroph is higher during the progesterone-dominated phase of the estrous cycle in mares, but regulatory mechanisms are not well understood. METHODS mRNA expression of glycogen-metabolizing enzymes (HK1, HK2, GSK3B, GYS1, PEPCK, PKM, PYGM) in endometrial samples were compared among mares in anestrus, estrus, and at Day 12 of diestrus and pregnancy. In addition, hexokinase 2 (HK2) activity was assessed using a colorimetric assay. RESULTS HK2 was the key regulator of glycogen accumulation during diestrus and pregnancy; hexokinase transcript abundance and enzyme activity were significantly higher during diestrus and pregnancy than estrus and anestrus. In addition, despite similar relative transcript abundance, hexokinase activity was significantly greater in the pregnant versus diestrous endometrium. Therefore, we inferred there was regulation of hexokinase activity through phosphorylation, in addition to its regulation at the transcriptional level during early pregnancy. Based on immunohistochemistry, HK2 was localized primarily in luminal and glandular epithelial cells, with weaker staining in stromal cells. CONCLUSION Among glycogen metabolizing enzymes identified, expression of HK2 was significantly greater during the progesterone-dominated phase of the cycle.
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Affiliation(s)
- Sarah A. Bramer
- Department of Veterinary and Clinical Diagnostic Sciences, University of Calgary, Faculty of Veterinary Medicine, 3280 Hospital Dr NW, Calgary, AB T2N 4Z6 Canada
| | - Alysson Macedo
- Department of Veterinary and Clinical Diagnostic Sciences, University of Calgary, Faculty of Veterinary Medicine, 3280 Hospital Dr NW, Calgary, AB T2N 4Z6 Canada
| | - Claudia Klein
- Department of Veterinary and Clinical Diagnostic Sciences, University of Calgary, Faculty of Veterinary Medicine, 3280 Hospital Dr NW, Calgary, AB T2N 4Z6 Canada
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Klein V, Müller K, Schoon HA, Reilas T, Rivera del Alamo MM, Katila T. Effects of Intrauterine Devices in Mares: A Histomorphological and Immunohistochemical Evaluation of the Endometrium. Reprod Domest Anim 2015; 51:98-104. [DOI: 10.1111/rda.12651] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 11/07/2015] [Indexed: 11/30/2022]
Affiliation(s)
- V Klein
- Institute of Pathology; Faculty of Veterinary Medicine; University of Leipzig; Leipzig Germany
| | - K Müller
- Institute of Pathology; Faculty of Veterinary Medicine; University of Leipzig; Leipzig Germany
| | - HA Schoon
- Institute of Pathology; Faculty of Veterinary Medicine; University of Leipzig; Leipzig Germany
| | - T Reilas
- Natural Resources Institute Finland; Ypäjä Finland
| | - MM Rivera del Alamo
- Unit of Reproduction; Faculty of Veterinary Medicine; Autonomous University of Barcelona; Bellaterra Barcelona Spain
| | - T Katila
- Department of Production Animal Medicine; Faculty of Veterinary Medicine; University of Helsinki; Saarentaus Finland
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Lehmann J, Ellenberger C, Hoffmann C, Bazer FW, Klug J, Allen WR, Sieme H, Schoon HA. Morpho-functional studies regarding the fertility prognosis of mares suffering from equine endometrosis. Theriogenology 2012; 76:1326-36. [PMID: 21855986 DOI: 10.1016/j.theriogenology.2011.06.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2010] [Revised: 06/01/2011] [Accepted: 06/03/2011] [Indexed: 11/16/2022]
Abstract
The aim of the present study was to characterize the morpho-functional features of endometrosis in barren and foaling mares, using both conventional histopathological and immunohistochemical methods. Endometrial biopsy samples were collected during the physiological breeding season from 159 estrous, clinically healthy mares (mean age 12 years), and the quality and degree of endometrosis was histomorphologically defined. The mares were bred and those that foaled were put in the foaling group whereas those that did not foal were placed in the barren group. Foaling mares were then compared with barren mares. Sixty-four percent (101/159) of uterine samples showed varying degrees of endometrosis and were used for this study. The sample population consisted of 51 barren and 50 foaling mares suffering from endometrosis. Expression of steroid hormone receptors (estrogen receptor, progesterone receptor) and endometrial protein secretion patterns (uteroglobin [UG], uterocalin [UC], calbindin(D9k) [CAL], uteroferrin [UF]) was evaluated by immunohistochemistry (barren mares N = 51, foaling mares N = 31). In comparison with unaffected glands, fibrotic glands generally showed a cycle-asynchronous, partially patchy protein expression pattern which is interpreted as a sign of endometrial maldifferentiation within fibrotic areas. In barren mares (N = 51) more than half of biopsy samples (27/51) showed a destructive mostly moderate (20/27) type of endometrosis. In affected glands, staining for UG (17/21) was decreased (P < 0.001). Foaling mares (N = 50) frequently showed a mild, nondestructive endometrosis (35/50). Compared with barren mares, foaling mares had statistically (P < 0.05) more often a cycle-synchronous or increased UG expression pattern within fibrotic glands. Obvious deviations of either UG or UC rarely occurred. Within fibrotic foci, UF often demonstrated a cycle-synchronous or more intense expression pattern in both foaling (28/31) and barren mares (41/51), compared with healthy glands. Mares of both groups showed a cycle-asynchronous staining for estrogen receptor and progesterone receptor in the stromal cells in areas of periglandular fibrosis and the glandular epithelia. These findings indicate that affected areas become independent of the uterine control mechanisms and exhibit specific differentiation dynamics. Immunohistochemical investigations showed that the secretory patterns differ between barren and foaling mares. The findings in this study should be considered as a useful addition to the "classical" Kenney categorization.
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Affiliation(s)
- J Lehmann
- University of Leipzig, Faculty of Veterinary Medicine, Institute of Pathology, Leipzig, Germany.
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