Serum amyloid A and plasma fibrinogen concentrations in horses following emergency exploratory celiotomy

Enzyme-Linked Immunosorbent Assay (ELISA) Development for Equine Serum Amyloid A (SAA) Determination Using Recombinant Proteins

We aimed to develop a species-specific ELISA for qualitatively and quantitatively determining serum amyloid A (SAA) in horses. Current methods for measuring SAA in horses utilize ELISA or immunoturbidimetric tests designed for human SAA, which are not specific to horses. Mice and rabbits were used to generate polyclonal antibodies against equine SAA. The study examined serum samples from 32 horses with acute inflammatory disease (SG) and 25 clinically healthy horses. Furthermore, the SAAeq kinetics were observed in three horses from the SG group at three different timepoints. The SAA-ELISA established a cut-off at 0.06 OD492nm, where values equal to or higher than this were deemed positive, while values below it was considered negative. The test exhibited a sensitivity of 94% and specificity of 92%, resulting in an overall accuracy of 93%. The positive and negative predictive values were 94% and 92%, respectively. Coefficients of variation for inter- and intra-assay were 6.1% and 7.46% for SG and 9.6% and 9.63% for the control group (CG). The detection limit was determined to be 0.067. The SAA-ELISA proved its worth by demonstrating satisfactory performance, paving the way for the development of automated quantitative tests and species-specific semi-quantitative tests. This paves the way for their application in practical field settings.

Differences in bone turnover markers and injury risks between local and international horses: A Victorian Spring Racing Carnival study

BACKGROUND

Musculoskeletal injuries (MSI) are common in racehorses and have been of increasing concern in horses travelling internationally to compete. Understanding the differences in bone turnover between local horses and international horses following long-distance air transportation may inform MSI prevention strategies.

OBJECTIVES

To understand the differences in bone turnover markers and risk of MSI between local horses and international horses following long-distance air transportation.

STUDY DESIGN

Prospective cohort.

METHODS

The concentrations of bone turnover markers (OCN and CTXI), markers of stress (cortisol), inflammation (serum amyloid A) and circadian rhythm (melatonin), and bisphosphonates were determined in blood samples collected twice (14-17 days apart), from horses following international travel (n = 69), and from local horses (n = 79). The associations between markers, long-distance travel and MSI were determined using multivariable generalised linear regression models.

RESULTS

Within 3-5 days post-transport, concentrations of cortisol in international horses were higher than those of local horses (main effect, Coef. 0.39; 95% CI 0.24, 0.54; p < 0.001) but they decreased and were not different to those of local horses at the second timepoint (interaction effect, Coef. -0.27; 95% CI -0.46, -0.07; p = 0.007). After adjusting for age and sex, OCN and CTXI were not significantly different between international and local horses; however, OCN was lower in international horses at timepoint 2 (interaction effect, Coef. -0.16; 95% CI -0.31, -0.01; p = 0.043). The prevalence of MSI was higher in the international (26%; 95% CI 16, 38%) compared with local horses (8%; 95% CI 3, 16%; p < 0.001), with all severe MSI sustained by the international horses. At the second timepoint compared with the first timepoint post-transport, cortisol remained high or increased (interaction effect, Coef. 0.43; 95% CI 0.24, 0.61; p < 0.001) and OCN increased (interaction effect, Coef. 0.26; 95% CI 0.08, 0.44; p = 0.006) in the horses that sustained severe MSI.

MAIN LIMITATIONS

Horse population and racing career parameters differed between groups. Bone turnover markers have low sensitivity to detect local bone changes.

CONCLUSIONS

Most horses showed minimal effects of long-distance air transport within 2 weeks relative to local horses as assessed by stress and bone turnover markers. Screening for persistent high cortisol and evidence of net bone formation after long-distance air transportation may help to identify racehorses at high risk of catastrophic MSI.

A systematic review of the prevalence of post-operative complications after general anaesthesia in adult horses (2000-2023)

BACKGROUND

Equine post-operative morbidity represents a significant concern for both veterinary surgeons and horse owners.

OBJECTIVES

To estimate the prevalence of post-operative complications in horses after elective/non-abdominal surgery or colic surgery.

STUDY DESIGN

Systematic review.

METHODS

A database search identified eligible studies which reported the prevalence of equine post-operative complications published as a full paper in English in a peer-reviewed journal between 2000 and 2023. Studies were evaluated using the JBI Critical Appraisal Checklist for Prevalence Studies and GRADE (Grading of Recommendations, Assessment, Development and Evaluations) framework. Data for the most commonly reported complications were analysed using Chi-squared analysis of weighted means to answer 13 PICO (Population, Intervention, Comparator and Outcomes) questions.

RESULTS

Sixty-seven studies met inclusion criteria. Data for eight post-operative morbidities (colic, surgical site complications, myopathy/neuropathy, laminitis, diarrhoea/colitis, fever/pyrexia, jugular thrombophlebitis/thrombosis, respiratory complications) were sufficient to allow statistical analyses. The weighted mean of the overall proportion of post-operative complications after elective/non-abdominal surgery is 17.48% (95% confidence interval [95% CI]: 13.20-22.92), significantly increasing to 55.62% (95% CI: 45.79-65.03) after colic surgery (odds ratio [OR] 6.63; 95% CI: 5.83-7.56; p < 0.001). The most commonly reported morbidity was post-operative colic, with a weighted mean prevalence of 7.45% (95% CI: 4.83-11.76) after elective/non-abdominal surgery, significantly rising to 26.46% (95% CI: 19.11-35.97) after colic surgery (OR 4.11; 95% CI: 3.60-4.71; p < 0.001). The weighted mean prevalence of surgical site complications, laminitis, diarrhoea/colitis, fever/pyrexia, jugular thrombophlebitis/thrombosis and respiratory complications were significantly higher after colic surgery compared with elective/non-abdominal surgery. Myopathy/neuropathy was the only morbidity where prevalence was not different between groups (OR 1.86; 95% CI: 0.86-4.16; p = 0.16).

MAIN LIMITATIONS

The majority of studies were retrospective. Morbidity definitions, data collection periods, follow-up time and methods varied between studies.

CONCLUSIONS

Based on current evidence, the prevalence of post-operative colic, surgical site complications, laminitis, diarrhoea/colitis, fever/pyrexia, jugular thrombophlebitis/thrombosis and respiratory complications is significantly higher after colic surgery compared with elective/non-abdominal surgery under general anaesthesia.

Critical Care of the Colic Patient: Monitoring, Fluid Therapy, and More

A successful outcome to management of the critical colic patient is highly dependent on how the patient is monitored and treated, particularly, in the perioperative period. In this article, we will provide an update on monitoring techniques, advances in fluid therapy, nutrition management and pharmacotherapeutic agents, inclusive of pain monitoring and management, prokinetics, and management of systemic inflammatory response syndrome and the hypercoagulable state.

Basic Postoperative Care of the Equine Colic Patient

The 3 time periods around colic surgery (preoperative, operative, and postoperative) are all critical to successful outcomes. Although much focus is often paid to the first 2 time periods, the importance of sound clinical judgment and rational decision-making in the postoperative period cannot be overstated. This article will outline the basic principles of monitoring, fluid therapy, antimicrobial therapy, analgesia, nutrition, and other therapeutics routinely used in patients following colic surgery. Discussions of the economics of colic surgery and expectations for normal return to function will also be included.

Serum amyloid A does not predict non-survival in hospitalised adult horses with acute colitis

BACKGROUND

Predicting non-survival in horses with acute colitis improves early decision making. Therefore, this study aimed to determine the prognostic value of serum amyloid A (SAA) and other clinicopathological and clinical variables in adult horses with acute colitis.

METHODS

Clinical variables, SAA and other blood biomarkers, including plasma L-lactate (lactate), were assessed in 176 horses with acute colitis. A multivariate model for the prediction of non-survival was constructed. Icelandic horses were analysed separately.

RESULTS

Admission SAA was similar in survivors (median 548 mg/L; range 0-5453 mg/L) and non-survivors (396 mg/L; 0-5294) (p = 0.43). A model for non-survival included year of admission, lactate, heart rate, age and colic duration of more than 24 hours. Icelandic horses had a relative risk of 2.9 (95% confidence interval = 2.2-3.8) for acute colitis compared to other breeds. Lactate in Icelandic horses was higher than that in other breeds in both survivors (4.0 mmol/L, range 1.0-12.7 vs. 2.0, 0.7-12.5) and non-survivors (10.0, 1.5-26 vs. 5.4, 0.8-22) (p < 0.001).

LIMITATIONS

The prognostic value of repeated measurements of SAA could not be assessed in this study, as 71% of the non-surviving horses died within a day of admission.

CONCLUSION

Admission SAA did not predict non-survival. Breed needs consideration when lactate is evaluated as a predictor for non-survival in horses with colitis.

Use of serum amyloid A in equine medicine and surgery

Serum amyloid A (SAA) has become an indispensable part of the management of equine patients in general practice and specialized hospital settings. Although several proteins possess acute phase properties in horses, the usefulness of SAA exceeds that of other acute phase proteins. This is due to the highly desirable kinetics of the equine SAA response. SAA concentrations exhibit a rapid and pronounced increase in response to inflammation and a rapid decline after the resolution of inflammation. This facilitates the detection of inflammatory disease and real-time monitoring of inflammatory activity. SAA may be used in all stages of patient management: (1) before diagnosis (to rule in/rule out inflammatory disease), (2) at the time of diagnosis (to assess the severity of inflammation and assist in prognostication), and (3) after diagnosis (to monitor changes in inflammatory activity in response to therapy, with relapse of disease, or with infectious/inflammatory complications). By assessing other acute phase reactants in addition to SAA, clinicians can succinctly stage inflammation. White blood cell counts and serum iron concentration change within hours of an inflammatory insult, SAA within a day, and fibrinogen within 2-3 days; the interrelationship of these markers thus indicates the duration and activity of the inflammatory condition. Much research on the equine SAA response and clinical use has been conducted in the last decade. This is the prerequisite for the evidence-based use of this analyte. However, still today, most published studies involve a fairly low number of horses. To obtain solid evidence for use of SAA, future studies should be designed with larger sample sizes.

Biomarkers of Intestinal Injury in Colic

Biomarkers are typically proteins, enzymes, or other molecular changes that are elevated or decreased in body fluids during the course of inflammation or disease. Biomarkers pose an extremely attractive tool for establishing diagnoses and prognoses of equine gastrointestinal colic, one of the most prevalent causes of morbidity and mortality in horses. This topic has received increasing attention because early diagnosis of some forms of severe colic, such as intestinal ischemia, would create opportunities for rapid interventions that would likely improve case outcomes. This review explores biomarkers currently used in equine medicine for colic, including acute phase proteins, proinflammatory cytokines, markers of endotoxemia, and tissue injury metabolites. To date, no single biomarker has been identified that is perfectly sensitive and specific for intestinal ischemia; however, L-lactate has been proven to be a very functional and highly utilized diagnostic tool. However, further exploration of other biomarkers discussed in this review may provide the key to accelerated identification, intervention, and better outcomes for horses suffering from severe colic.

Evaluation of serum concentration of acute-phase proteins (haptoglobin and serum amyloid A) in the affected Arabian foals with rhodococcosis

BACKGROUND

Early detection of Rhodococcus equi pneumonia in foals is essential for horse health and for veterinarians.

OBJECTIVES

This study aimed to demonstrate the usefulness of assessing the serum concentration of acute-phase proteins (APPs) in the early diagnosis of pneumonia.

METHODS

The study evaluated APPs in 19 Arabian foals with R. equi pneumonia and compared them with 18 normal Arabian foals in equestrian clubs in Tabriz, Iran. Affected foals were identified through history, clinical findings and bacterial culture of tracheal washing. Biochemical methods and polymerase chain reaction tests were performed by examining the 16S rRNA and vapA genes to confirm the diagnosis of bacterial isolates. Blood samples were taken from all sick and healthy horses, and their serum was isolated. APPs in the serum were measured in all the samples.

RESULTS

Rhodococcosis increased the serum concentration of haptoglobin (Hp) and serum amyloid A (SAA) (p < 0.001). The relationship between SAA and Hp was meaningful in the infected group (r = 0.933) but not in the healthy group. In cases where there are clinical findings of R. equi pneumonia, the concentration of SAA and Hp can help the effectiveness of treatment.

- CONCLUSIONS

Serum concentration analysis of APPs can be helpful in early diagnosis and successfully treating foals with R. equi pneumonia.

Diagnostic value of Serum Amyloid A, Interleukin-6 in gravidas with spontaneous preterm birth

PURPOSE

Spontaneous preterm birth (SPB) can't be predicted accurately nowadays. We aim to investigate the value of serum amyloid A(SAA) and interleukin-6(IL-6) for forecasting the risk of SPB.

METHODS

A total of 302 pregnant women who completed delivery in our hospital from January 2019 to December 2021 were included. According to gestational days, they were divided into the case group (28-33⁺⁶ weeks, 41 cases; 34-36⁺⁶ weeks, 96 cases) and the control group (37-42 weeks, 165 cases). The general data of the two groups were analyzed and the values of SAA and IL-6 in speculating the risk of SPB were studied in this study.

RESULTS

The levels of SAA and IL-6 in the case group were higher than those in the control group(P < 0.05), and the most practical value of SAA and IL-6 access SPB risk were 17.35 mg/L, 112.41 pg/mL respectively. The area under the ROC curve of diagnosis to predict SPB were 0.8849, 0.8664.

CONCLUSIONS

The assessment of SPB risk by SAA and IL-6 bearscertain clinical value, which could assist clinicians in recognizing and evaluating the potential dangers of SPB.

Study design synopsis: Observational study design in equine research

When planning to conduct research, thorough consideration of the study design is essential to enable valid results and purposeful conclusions. A good study design will provide a strong basis for robust conclusions that can contribute to the evidence base. Conversely, a poor study design may unintentionally lead to invalid conclusions with inappropriate claims of the clinical importance. The purpose of this article is to review important aspects of observational study design, with an emphasis on observational clinical research. The value of an observational study can be manifold and the benefit of studying clinical cases can add substantial value to the evidence base and equine health and welfare, however this value will be diminished if study designs are flawed, or are inadequately reported. It is essential that clinicians have the skills to critically appraise observational studies, to determine strengths, limitations and the applicability to their clinical practice.