The usefulness of uterine lavage and acute phase protein levels as a diagnostic tool for subclinical endometritis in Icelandic mares

Abstract

BackgroundEndometritis is a common problem in a broodmare practice, often leading to infertility. The diagnosis is based on several methods such as cytology, bacteriology and histopathology; however the outcome of these methods may be inconclusive even when used together. The objectives of this study were: (1) to investigate the usefulness of acute phase proteins as an additional diagnostic tool for diagnosis of subclinical endometritis in mares and (2) to evaluate the association between macroscopic changes in uterine flushes and inflammation of the uterus. Materials were collected from 53 Icelandic mares with subclinical endometritis. Endometrial swabs and uterine lavage for cytological and bacteriological examinations and two endometrial biopsies were taken. Blood samples were collected 12–24 h after ovulation to determine the concentrations of serum amyloid A and haptoglobin in the 53 subfertile mares and, for comparison, from 20 non-pregnant mares that later conceived.ResultsTwenty-five mares were classified as positive for endometritis based on endometrial biopsy, which was used as the ‘gold standard’. We observed a correlation between cloudy efflux in the lavage and (1) polymorphonuclear cell (PMN) infiltration of the endometrium (P = 0.031), (2) positive cytology in samples obtained by cotton swabs (P = 0.019) and uterine lavage (P = 0.011), and (3) positive microbiology from samples obtained by cotton swabs (P = 0.001) and uterine lavage (P = 0.047). The degree of agreement between PMN infiltration and positive cytology from samples taken by cotton swabs and uterine lavage was fair to moderate. We found no association between the concentration of acute phase proteins and infiltration of the endometrium by PMNs, or with positive results of cytological and microbiological examinations.ConclusionsMeasurement of serum amyloid A and haptoglobin was not proven useful for diagnosis of subclinical endometritis in Icelandic mares. Macroscopic changes in the fluid collected by lavage were not consistently indicative of infection, but when present they indicate inflammation in the uterus with a high probability.

Equine Inflammatory Markers in the Twenty-First Century

“…A commonly accepted reference interval for SAA concentration in horses is 0 to 20 mg/L, 15 with most reports finding normal horses have SAA values at or lower than 12 mg/L. 6,8,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Several studies have examined the utility of SAA for discriminating between horses with or without inflammation. Animals with systemic inflammation had significantly higher SAA concentrations (mean, 1583 mg/L; range, 688-4000 mg/L) than horses with local or no inflammation (mean of 343 mg/L and range of 37-1609, and mean of 5.6 mg/L and range of 1.8-14.5 mg/L, respectively).…”

“…20 Most reports have found no changes in serum SAA concentrations following breeding or infectious endometritis. 22,28,64,65 Only one study showed a significant increase in serum APP levels (SAA and fibrinogen) after experimental induction of endometritis. 66 Based on these results, measurement of SAA concentrations does not seem to be useful for endometritis assessment in horses.…”

Reliability of histopathological examination and immunohistochemistry of a single biopsy for evaluation of endometrial health in Icelandic mares

“…Animals. The study was conducted on 53 Icelandic Horse mares, aged from 3 to 25 years (12.34 ± 5.72 years, mean ± SD), which were classified for the study as described by Sikora et al [24]. This study was approved by Icelandic Food and Veterinary Authority with a reference number of approval 2014-01-04.…”

“…All the samples were obtained during at the same sampling procedures and that lasted less than 15 min. The endometrial swab (ES) and uterine lavage (UL) were collected for another part of the study, published by Sikora et al [24]. In this paper the main subject of study is histopathological examination of endometrial biopsies, collected from mares, as well as the assessment of immunohistochemical reactivity of the stroma to antibody against fibronectin and reactivity of the surface and glandular epithelia to antibody against PTGS-2 in the same endometrial biopsies.…”

“…Generally, in practice only a single uterine biopsy is collected; however, several authors reported that the diagnosis based on the one sample could be misleading and incomplete [22][23][24]. Fiala et al [22] in their study performed after slaughter showed that a single biopsy is not sufficiently accurate to determine the type and severity of inflammation in mares' endometrium.…”