Serum Levels of Acute Phase Proteins: SAA, Hp and Progesterone (P4) in Mares with Early Embryonic Death

Relationship between estrus endometrial edema and progesterone production in pregnant mares two weeks after ovulation

BACKGROUND

Progesterone plays a crucial role in the maintenance of pregnancy from conception to about 100-120 days of gestation when placenta becomes the main source of gestagens. The aim of the study was to test progesterone concentration 14 days after ovulation in pregnant mares and relate it to peak estral endometrial edema and the presence of intrauterine fluid (IUF) after artificial insemination (AI), the number of treatments against IUF, and the time from AI to the day when the uterus was found free of fluid.

RESULTS

Mares were divided into two groups: group A (n = 13; age 10.8 ± 4.5 years) in which a normal embryonic vesicle with a diameter ≥ 14 mm and a corpus luteum with a diameter ≥ 15 mm were found 14 days after ovulation, and group B (n = 22; age 9.4 ± 4 .0 years) in which 14 days after ovulation, a small (< 15 mm) corpus luteum and/or a small embryonic vesicle was observed (diameter < 14 mm). Mares from group A had a significantly higher progesterone concentrations at 14 days after ovulation compared with group B mares. The presence of IUF, the number of treatments against IUF, and the time from AI to the day when uterus was found free of fluid did not affect progesterone concentration measured 14 days after ovulation. In group B, a significant correlation was found between progesterone concentration measured 14 days after ovulation and endometrial edema evaluated during estrus.

CONCLUSIONS

In some cases poor development of endometrial edema during estrus can be associated with lower progesterone production 14 days after ovulation. Nevertheless, scientific explanation for this finding cannot be given based on our study.

Interrelationship between reproductive hormones and acute phase proteins during estrous cycle and pregnancy in Spanish purebred broodmares

In some species, female steroid hormones modify the profile of acute phase proteins (APPs) during the estrous cycle and pregnancy, according to the ovulation, embryonic implantation and placental development; however, nowadays there's no experimental evidence for equine species. Objectives of this study were: to compare the serum amyloid A (SAA), haptoglobin (Hp) and C-reactive protein (CRP) concentrations between cyclic and pregnant mares, and to analyze the influence of estradiol-17β (E2) during estrous cycle or estrone sulfate (E1) during pregnancy, and progesterone (P4) on these proteins to assess their potential role to identify the cyclicity or pregnancy in Spanish mares. Blood samples were taken from 20 Purebred Spanish mares on the day of ovulation (day 0), on days +5 and +16 post-ovulation, and then, monthly during the whole pregnancy. SAA, Hp and CRP did not change between day 0, +5 and +16 post-ovulation days. P4 concentrations were significantly higher on day +16 than on days +5 and 0; and E2 concentrations were significantly higher on day 0 than day +5. On the other hand, pregnancy was characterized by a progressive increase in the Hp, variable modifications of E1 and P4 concentrations, without changes in SAA and CRP. The absence of significant differences in the APPs between days 0, +5 and +16, suggested that these proteins cannot be used as biomarkers of diagnosis of heat or pregnancy in Spanish mares, at least early, since the Hp later increases during the gestation. Nevertheless, it is possible to use them for comparative purposes with other equine breeds, as supervisor instrument of health status in breeding females as diagnostic tools to monitor pregnancy's development and/or subclinical reproductive inflammations, that could lead to the early embryonic death.

Serum amyloid A, Serum Amyloid A1 and Haptoglobin in pregnant mares and their fetuses after experimental induction of placentitis

Serum amyloid A (SAA) and Haptoglobin (Hp) are acute phase proteins, produced during inflammation, such as placentitis. In horses, SAA and SAA1 are protein coding genes. Objectives were to analyze SAA and Hp concentrations and relative abundance of SAA, SAA1 and Hp mRNA transcript in maternal and fetal tissues after experimental induction of placentitis or mares of a control group. Serum Amyloid A family proteins were in marked abundance in the stroma of the endometrium and chorioallantois associated with inflammatory cells. Maternal plasma SAA concentrations were greater (P = 0.01) in mares with experimentally induced placentitis compared to those of the control group. Maternal Hp from the groups were not different, but fetal Hp concentrations of mares with experimentally induced placentitis were greater (P = 0.02). Maternal plasma SAA and Hp concentrations were greater than fetal plasma concentrations in mares with experimentally induced placentitis (P < 0.05). Relative abundance of SAA mRNA transcript was greater in the maternal, fetal liver and chorioallantois of mares with experimentally induced placentitis (P < 0.05) compared to those in the control group. Interestingly, relative abundance of SAA1 mRNA transcript was greater in the chorioallantois of mares with experimentally induced placentitis (P < 0.05). The SAA and Hp concentrations, therefore, were greater in mares with induced placentitis. Furthermore, relative abundance of SAA1 mRNA transcript is specifically greater in the chorioallantois of mares with placentitis, which warrants further studies to elucidate the immunological response of SAA1 in the chorioallantois of mares with placentitis.

Changes in the Secretion of Anti-Inflammatory Cytokines and Acute-Phase Proteins in the Uterus after Artificial Insemination in the Mare

Simple Summary

Semen deposition into the uterus during mating or artificial insemination induces a rapid inflammatory response, and, in susceptible mares, persistent endometritis can develop. Cytokines are mediators involved in the regulation of the inflammatory process, and acute phase proteins are the most sensitive indicators of the inflammatory process. Therefore, the aim of this research was to determine the secretion of anti-inflammatory cytokines and acute-phase proteins in the uterus before and after artificial insemination in the mare. The obtained results indicate that the status of the mare before artificial insemination has little effect on the response measured shortly after artificial insemination. The presence of intrauterine fluid during estrus is not connected with the inflammation parameters investigated in this study at 7 h post artificial insemination. Detailed examination of the mare’s reproductive tract before and after artificial insemination guarantees high fertility.

Abstract

The objective of the study was to evaluate the concentrations of interleukin-1 receptor antagonist (IL-1RA), interleukin-10 (IL-10), serum amyloid A (SAA) and haptoglobin (Hp) in uterine lavage fluid before and after artificial insemination (AI). Based on ultrasound examination, mares were divided into: Group 1 (n = 9), no fluid was detected in the uterus during estrus and 7 h after AI; Group 2 (n = 8), no fluid was detected in the uterus during estrus but 7 h after AI fluid was detected in the uterus; Group 3 (n = 8), fluid was detected in the uterus during estrus and also 7 h after AI. In all groups of mares, a significant increase in polymorphonuclear cells (PMN) and a significant increase in IL-1RA and SAA were recorded 7 h after AI. The obtained results show that, regardless of the status of the mare before AI, the endometrial response characterized by PMN influx, and SAA, Hp, IL-1RA and IL-10 production, is similar. The presence of intrauterine fluid during estrus is not connected with PMN influx but can impact uterine IL-1RA production at this time.

The Level of Prolactin, Serum Amyloid A, and Selected Biochemical Markers in Mares Before and After Parturition and Foal Heat

The aim of the study was to determine the level of prolactin (PRL), serum amyloid A (SAA), and selected biochemical markers (T-Chol, AST, TP, Mg²⁺, P⁺, and Ca²⁺) in the blood of mares during the perinatal period. The study involved 14 mares of the Polish Coldblood Horse breed, which were in the third trimester of pregnancy. Blood was collected for testing 2 weeks before parturition and then 24 hours after delivery and in the foal heat (9 days) and 9 days after ovulation and breeding. The research revealed significant differences in the level of PRL and SAA before and after delivery. The highest PRL level was found 24 hours after delivery, lowest in foal heat and 9 days after ovulation. Serum amyloid A concentration was within the accepted norms; however, on day 9 after foaling, a significant increase of this protein was observed. All biochemical markers were within physiological limits. However, significant increases in T-Chol, AST, and TP levels was observed 24 hours after the delivery, whereas in foal heat and after ovulation levels of T-Chol and TP significantly decreased and the AST level remained at a similar level. There were no significant changes in electrolyte levels such as Mg²⁺, P⁺, and Ca²⁺. The pregnancy rate in the foal heat was at 43%. Collectively, the results of this study in conjunction with clinical observations demonstrated that when the perinatal period was normal, no disturbances in health related to pregnancy, parturition, lactation, and reproductive status during the postpartum period were found.

Assessment of peripheral markers and ultrasonographic parameters in pregnant mares receiving intramuscular or intrauterine cloprostenol

The present study aimed to compare two methods of prostaglandin-induced abortion in mares by determining blood markers (progesterone, estradiol-17β, alpha-fetoprotein, 13,14-dihydro-15-keto-prostaglandin-F2α (PGFM)), B-mode ultrasonographic parameters, and time until loss of fetal heartbeat. It was hypothesized that intrauterine infusion of cloprostenol results in earlier fetal compromise than intramuscular administration. Ovarian structures (number and sizes of follicles and corpora lutea area), fetal heartbeat, and fetal mobility of thirteen singleton pregnancies were assessed daily by transrectal ultrasonography until induction of pregnancy termination (60 ± 2 days of gestation). Mares received 500 μg of cloprostenol intramuscularly every 12 h (IM, n = 7) or once transcervically (TC, n = 6). After initial cloprostenol administration, ultrasonographic examinations were repeated at 6-h intervals until loss of fetal heartbeat was detected. Plasma progesterone, estradiol-17β, and alpha-fetoprotein were assessed for five days before and after pregnancy loss. In addition, plasma PGFM concentrations were assessed immediately before cloprostenol administration (0 min), and then 15, 30, and 45 min, and 1, 2, 3, 4, 6, 12 h after administration. Data were analyzed using the MIXED procedure with repeated measures in SAS. Significance was set at P < 0.05. All mares lost their pregnancies within 48 h after initial cloprostenol administration, with no difference in time to pregnancy loss. There were significant effects of time starting by 12 h post-induction of pregnancy termination but there was no time by group interaction for progesterone concentrations. Estradiol-17β and alpha-fetoprotein concentrations were not altered upon impending abortion. Concentrations of PGFM increased significantly by 2 h after cloprostenol administration, but there were no differences between groups. No time effects or time by group interaction for fetal mobility and heartbeat was detected. Expectedly, the number and area of corpora lutea decreased significantly after cloprostenol administration with no significant differences between groups. In conclusion, intrauterine administration of cloprostenol was not different from repeated systemic administration to terminate the pregnancy. Both models for early fetal loss were equivalent for the endpoints assessed herein. The present study provides evidence that transcervical cloprostenol administration technique is repeatable in different settings and results in negligible side effects. While systemic administration results in colic-like signs and may result in severe reaction.

Serum amyloid A in equine health and disease

Serum amyloid A (SAA) is the major acute phase protein in horses. It is produced during the acute phase response (APR), a nonspecific systemic reaction to any type of tissue injury. In the blood of healthy horses, SAA concentration is very low, but it increases dramatically with inflammation. Due to the short half‐life of SAA, changes in its concentration in blood closely reflect the onset of inflammation and, therefore, measurement of SAA useful in the diagnosis and monitoring of disease and response to treatment. Increases in SAA concentration have been described in equine digestive, reproductive and respiratory diseases and following surgical procedures. Moreover, SAA has proven useful for detection of some subclinical pathologies that can disturb training and competing in equine athletes. Increasing availability of diagnostic tests for both laboratory and field use adds to SAA's applicability as a reliable indicator of horses’ health status. This review article presents the current information on changes in SAA concentrations in the blood of healthy and diseased horses, focussing on clinical application of this biomarker.

Successful embryo transfer from Hokkaido native pony after artificial insemination with frozen semen

There has been no report of equine embryo transfer in Japan for the last 24 years. Our objective was to establish an effective protocol for embryo transfer in domestic horse. A Hokkaido native pony was bred by deep-horn artificial insemination with frozen semen from a Connemara pony. Embryo collection was performed using a non-surgical method on day 7. Two embryos were obtained from three flushes (67% recovery) and were transferred fresh into crossbred recipient mares. Both recipient mares were diagnosed pregnant (100% pregnancy rate) 5 days after embryo transfer and had normal progesterone levels until the end of the observation on day 35 of gestation. This is the first successful embryo transfer in Japan by artificial insemination using frozen semen. Embryo transfer technology could be extremely useful in improving the productivity of Japanese domestic and special riding horses.

Patterns of conceptus development and of progesterone concentrations in maternal blood preceding spontaneous early pregnancy failure in mares

Sixteen cases of spontaneous pregnancy loss (11 of singletons and five of pairs of twins) are described. The losses occurred between gestation Days 13 and 25 in 12 mares being monitored almost daily by transrectal ultrasonography (for measurement of conceptus growth) and blood sampling (for determination of maternal plasma progesterone concentrations as evidence of luteolysis) in experimental studies of early pregnancy. In 10 of the 16 cases the uterus was flushed and eight conceptuses were recovered for morphological assessment. Five of the 11 losses of singletons occurred before Day 16 and, with one exception, were preceded or accompanied by luteolysis. The remaining six singleton pregnancies failed after Day 16, with two cases evidencing luteolysis beforehand. Thus, overall, 6/11 singleton losses were associated with luteolysis while 5/11 were not. The five cases of simultaneous loss or degeneration of twin conceptuses all occurred on Day 19 or 20, preceded by luteolysis in only one case. These observations suggest that while the causes of spontaneous early pregnancy failure are multifactorial, luteolysis might contribute to the problem more often than has been previously contended.

Serum amyloid A protein (SAA), haptoglobin (Hp) and selected hematological and biochemical parameters in wild mares before and after parturition

The aim of the study was to evaluate physiological changes in hematological and biochemical parameters in mares in perinatal period. Blood samples were collected from 24 pregnant Polish Konik breed mares which were divided into two groups. The first group (Group - I, n=12) comprised mares living in the wild, in the reserve. The second group (Group - II, n=12) consisted of mares kept in stables. The blood was collected 2 weeks prior to the parturition, then 24 hours after the delivery, and then at the 7th and 21st day after foaling. When comparing the two groups before the parturition, no significant differences in terms of WBC, RBC, and Hb were found, however, there was a significant difference in MCV, MCH, LYM, NEU and SEG NEU (p≤0.05). In Group II, 24 hours after the parturition and at the 21st day after foaling, a significant raise in WBC, NEU and SEG NEU (p≤0.05) was detected. No significant differences in serum concentrations of proteins such as TP, Alb or Glb were observed. As to acute phase proteins, significant rise in SAA and Hp (p≤0.05) was found in the two examined groups 24 hours after the parturition. Yet, this rise remained within physiological range. The study revealed a certain degree of fluctuations in hematological parameters, in serum concentrations of acute-phase proteins and total proteins in the mares in the perinatal period. However, these changes remained still within physiological ranges and thus they do not indicate potential susceptibility to disorders of perinatal period.

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

Background

Endometritis 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.

Results

Twenty-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.

Conclusions

Measurement 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.

Identification and verification of differentially expressed genes in the caprine hypothalamic-pituitary-gonadal axis that are associated with litter size

Litter size is a favorable economic trait for the goat industry, but remains a complex trait controlled by multiple genes in multiple organs. Several genes have been identified that may affect embryo survival, follicular development, and the health of fetuses during pregnancy. Jining Grey goats demonstrate the largest litter size among goat breeds indigenous to China. In order to better understand the genetic basis of this trait, six suppression subtractive hybridization (SSH) cDNA libraries were constructed using pooled mRNAs from hypothalamuses, pituitaries, and ovaries of sexually mature and adult polytocous Jining Grey goats, as testers, versus the pooled corresponding mRNAs of monotocous Liaoning Cashmere goats, as drivers. A total of 1,458 true-positive clones--including 955 known genes and 481 known and 22 unknown expressed sequence tags--were obtained from the SSH libraries by sequencing and alignment. The known genes were categorized into cellular processes and signaling information storage and processing, and metabolism. Three genes (FTH1, GH, and SAA) were selected to validate the SSH results by quantitative real-time PCR; all three were up-regulated in the corresponding tissues in the tester group indicating that these are candidate genes associated with the large litter size of Jining Grey goats. Several other identified genes may affect embryo survival, follicular development, and health during pregnancy. This study provides insights into the mechanistic basis by which the caprine hypothalamic-pituitary-gonadal axis affects reproductive traits and provides a theoretical basis for goat production and breeding.