Relationship between uterine biopsy score, endometrial infection and inflammation in the mare

Summary

Objective: Endometrial biopsy score is an accepted marker of uterine health and predicted fertility, and it has been suggested that endometrial alternations are correlated with susceptibility to persistent infectious endometritis. The objective of this study was to investigate associations of endometrial biopsy score with: 1) presence of polymorphonuclear cells (PMNs) in the epithelium and stratum compactum in histopathology; 2) presence of PMNs in cytology and 3) presence of infection in microbiology. Materials and methods: The material for examination was collected from 69 mares suspected for subclinical endometritis (bred three or more times unsuccessfully in the same breeding season) and from 15 maiden mares. Samples were collected by endometrial biopsy and cytobrush technique. Results: Endometrial alterations (biopsy score IIA, IIB, III) were found in 64 of 82 mares (78%). There was an increase in PMN occurrence for grades IIA, IIB and III. When comparing grades and PMNs infiltration, we observed statistically significant differences between grades I and IIA (p = 0.222) and grades I and IIB (p = 0.042) in samples collected by endometrial biopsy. Statistically significant differences were found in microbiological examination (biopsy p = 0.036; cytobrush p = 0.189), cytological examination (biopsy p = 0.040; cytobrush p = 0.079) and PMN infiltration (p = 0.042) between mares with biopsy scores I and IIB. Furthermore, the highest percentage of infected mares was in grade IIA and IIB, and we found statistically significant differences between grades I and IIA (p = 0.043), and grades I and IIB (p = 0.036) in biopsy samples. We observed a tendency to higher prevalence of endometrial infection in mares with biopsy score IIA, IIB and III than with biopsy score I in samples collected using cytobrush technique. However, there were no statistical significant differences. Conclusion: Degenerative endometrial changes can predispose to uterine infection and inflammation. Our study shows that mares with endometrial score I are less predisposed to infection than mares with category IIA, IIB and III. Endometrial biopsy is a reliable diagnostic tool.

Zusammenfassung

Gegenstand und Ziel: Der Endometriumbiopsie-Score (EBS) ist ein eta - blierter Parameter zur Beurteilung der Gebärmuttergesundheit und Fertilitätsprognose. Es wird davon ausgegangen, dass Endometriumveränderungen mit der Empfänglichkeit für persistierende chronische Entzündungen korrelieren. Die Studie untersuchte den Zusammenhang zwischen dem EBS und 1) der histopathologisch ermittelten Häufigkeit polymorphkerniger Zellen (PMNs) im Epithel und Stratum compactum; 2) der zytologisch bestimmten PMN-Häufigkeit und 3) einer mikrobiologisch festgestellten uterinen Infektion. Material und Methoden: Die mittels Endometriumbiopsie und Cytobrush-Technik entnommenen Proben stammten von 69 Stuten mit Verdacht auf subklinische Endometritis (drei oder mehr erfolglose Belegungen in der laufenden Decksaison) und von 15 Maidenstuten. Ergebnisse: Endo metriumveränderungen (EBS IIA, IIB, III) wurden bei 64 von 82 Stuten (78%) festgestellt. Die Häufigkeit von PMNs nahm bei Stuten der Ka tegorien IIA, IIB und III zu. Beim Vergleich der Bioptate von Stuten unterschiedlicher Kategorien lagen statistisch signifikante Unterschiede zwischen I und IIA (p = 0,222) sowie I und IIB (p = 0,042) vor. Es bestanden statistisch signifikante Unterschiede bei der mikrobiologi schen Untersuchung (Biopsie p = 0,036; Cytobrush p = 0,189), zytolo gischen Untersuchung (Biopsie p = 0,040; Cytobrush p = 0,079) und PMN-Infiltration (p = 0,042) zwischen Stuten der Kategorien I und IIB. Der höchste Prozentsatz infizierter Stuten fand sich in den Kategorien IIA und IIB und es ergaben sich statistisch signifikante Unterschiede zwischen den Stuten der Kategorie I und IIA (p = 0,043) sowie I und IIB (p = 0,036) bei den mittels Biopsie gewonnenen Proben. Eine Tendenz zu höherer Prävalenz einer uterinen Infektion zeigte sich bei den mittels Cytobrush gewonnenen Proben zwischen Stuten der Ka - te gorien IIA, IIB und III im Vergleich zu Stuten der Kategorie I. Schlussfolgerung: Degenerative Endometriumveränderungen können für uterine Infektionen und Entzündungen prädisponieren. Die Studie verdeutlicht, dass Stuten mit EBS I weniger empfänglich für eine Infektion sind als Stuten der Kategorien IIA, IIB und III. Die Endometriumbiopsie ist eine zuverlässige diagnostische Methode.

Keywords

Mare - endometrial biopsy - cytology - endometritis

Schlüsselwörter

Stute - Endometriumbiopsie - Zytologie - Endometritis

• Literatur

• 1 Aresu L, Benali S, Giannuzzi D, Mantovani R, Castagnaro M, Falomo M. The role of inflammation and matrix metalloproteinases in equine endometriosis. J Vet Sci 2012; 13: 171-177.
• 2 Ball BA, Shin SJ, Pattern VH, Lein DH, Woods GL. Use of a low-volume uterine flush for microbiologic and cytologic examination of the mares endometrium. Theriogenology 1988; 29: 1269-1283.
• 3 Blanchard TL, Cummings MR, Garcia MC, Hurtgen JP, Kenney RM. Comparison between two techniques for endometrial swab culture and between biopsy and culture in barren mares. Theriogenology 1981; 16 (05) 541-552.
• 4 Buczkowska J, Kozdrowski R, Nowak M, Raś A, Mrowiec J. Endometrosis - significance for horse reproduction, pathogenesis, diagnosis, and proposed therapeutic methods. Pol J Vet Sci 2014; 17 (03) 547-554.
• 5 Christoffersen M, Woodward E, Bojesen AM, Jacobsen S, Petersen MR, Troedsson MHT, Lehn-Jensen H. Inflammatory responses to induced infectious endometritis in mares resistant or susceptible to persistent endometritis. BMC Vet Res 2012; 8: 41.
• 6 Doig PA, McKnight JD, Miller RB. The use of endometrial biopsy in the infertile mare. Can VetJ 1981; 22: 72-76.
• 7 Hoffmann C, Ellenberger C, Mattos RC, Aupperle H, Dhein S, Stief B, Schoon HA. The equine endometrosis: New insights into the pathogenesis. Anim Reprod Sci 2009; 111: 261-278.
• 8 Keller A, Neves AP, Aupperle H, Steiger K, Garbade P, Schoon HA, Klug E, Mattos RC. Repetitive experimental bacterial infections do not affect the degree of uterine degeneration in the mare. Anim Reprod Sci 2006; 94: 276-279.
• 9 Kenney RM, Doig PA. Equine endometrial biopsy. Current Therapy in Theriogenology.. Marrow D. Philadelphia: Saunders; 1986: 723-729.
• 10 Kenney RM. Cyclic and pathologic changes of the mare endometrium as detected by biopsy, with a note on early embryonic death. J Am Vet Med A 1978; 172 (03) 241-262.
• 11 Kilgenstein HJ, Schöniger S, Schoon D, Schoon H-A. Microscopic examination of endometrial biopsies of retired sports mares: An explanation for the clinically observed subfertility?. Res Vet Sci 2015; 99: 171-179.
• 12 Kozdrowski R, Sikora M, Buczkowska J, Nowak M, Ras A, Dzicioł M. Effects of cycle stage and sampling procedure on interpretation of endometrial cytology in mares. Anim Reprod Sci 2015; 154: 56-62.
• 13 Nielsen JM, Nielsen FH, Petersen MR. Diagnosis of equine endometritis - Microbiology, cytology and histology of endometrial biopsies and the correlation to fertility. Pferdeheilk 2012; 28 (01) 8-13.
• 14 Nielsen JM, Troedsson MH, Pedersen MR, Lehen-Jensen H. Diagnosis of endometritis in the mare based on bacteriological and cytological examinations of the endometrium. Comparison of results obtained by swabs and biopsies. J Equine Vet Sci 2010; 30: 27-30.
• 15 Nielsen JM. Endometritis in the mare: a diagnostic study comparing cultures from swab and biopsy. Theriogenology 2005; 64: 510-518.
• 16 Overbeck W, Witte TS, Heuwieser W. Comparison of three diagnostic methods to identify subclinical endometritis in mares. Theriogenology 2011; 75: 1311-1318.
• 17 Rasmussen CD, Petersen MR, Bojesen AM, Pedersen HG, Lehn-Jensen H, Christoffersen M. Equine infectious endometritis - clinical and subclinical cases. J Equine Vet Sci 2015; 35: 95-104.
• 18 Ricketts SW, Alonso S. Assessment of the breeding prognosis of mares using paired endometrial biopsy techniques. Equine VetJ 1991; 23: 185-188.
• 19 Ricketts SW, Barrelet A. A retrospective review of the histopathological features seen in series of 4241 endometrial biopsy samples collected from UK Thoroughbred mares over a 25 year period. Pferdeheilk 1997; 13: 525-530.
• 20 Ricketts SW. The technique and clinical application of endometrial biopsy in the mare. Equine Vet J 1975; 7 (02) 102-107.
• 21 Schlafer DH. Equine endometrial biopsy: Enhancement of clinical value by more extensive histopathology and application of new diagnostic techniques?. Theriogenology 2007; 68: 413-422.
• 22 Williamson P, Munyua SJM, Penhale J. Endometritis in the mare: a comparison between reproductive history and uterine biopsy as techniques for predicting susceptibility of mares to uterine infection. Theriogenology 1989; 32 (03) 351-357.
• 23 Woodward EM, Christoffersen M, Campos J, Squires EL, Troedsson MHT. Susceptibility to persistent breeding-induced endometritis in the mare: Relationship to endometrial biopsy score and age, and variations between seasons. Theriogenology 2012; 78: 495-501.
• 24 Zajac S, Katkiewicz M, Witkowski M, Boryczko Z, Pawlak M. Endometrosis in mares. Med Weter 2008; 64: 257-261.