Use of serum amyloid A and other acute phase reactants to monitor the inflammatory response after castration in horses: a field study

A scoping review on intraoperative and postoperative surgical castration complications in domesticated equids

BACKGROUND

Castration is the most common surgical procedure in domesticated equids; surgical techniques used and perioperative management vary considerably.

OBJECTIVES

To identify and chart the current evidence on perioperative complications associated with different methods of surgical castration in domesticated equids.

STUDY DESIGN

Joanna Briggs Institute systematic scoping review.

METHOD

CAB Abstracts, Medline and Embase databases were searched using terms related to equine castration complications. Two authors independently and blindly screened publications against eligibility criteria. Data on study methods, perioperative management, surgical techniques, and perioperative complications were extracted. Surgical techniques were grouped into categories depending on technique; open, closed or half-closed, and whether the parietal tunic was open or closed at the end of surgery.

RESULTS

The search identified 1871 publications; 71 studies met the final inclusion criteria. The data reported 76 734 castrations, most of which were open or closed, with the vaginal tunic remaining open at the end of surgery. Twenty-five studies reported information regarding surgical techniques and perioperative management, allowing detailed charting and comparisons, of which analgesia and antimicrobial usage varied notably. Eighteen different complications were reported, with swelling or oedema being the most common. Evisceration was most commonly reported in draught breeds and Standardbreds, and the risk appeared low if the parietal tunic was closed at the end of surgery.

MAIN LIMITATIONS

Grey literature and studies not available in English were not included. Existing studies varied greatly in perioperative management, surgical techniques and reporting of outcomes, making evidence consolidation problematic.

CONCLUSION

A lack of consensus regarding complication definitions creates uncertainty and discrepancies between complication rates associated with different surgical techniques and perioperative management. The implementation of standardised systems for describing surgical techniques and complications is recommended for future studies. A number of studies did not follow current recommendations for perioperative analgesia and use of antimicrobials.

Iron-related markers of inflammation in horses with colic

The aim of the study was to compare and correlate levels of ferritin, transferrin, iron and APPs in healthy horses and those surgically treated for strangulating colic. On admission, measurements of inflammatory markers related to iron and total protein, fibrinogen, albumin, haptoglobin and ceruloplasmin were made. The study comprised 22 horses, divided into a control group (CG) of healthy horses (n = 10) and horses with surgically treated acute abdomen (n = 12), obstruction group (OG). The OG was subdivided according to the affected intestinal segment (small vs. large) and according to outcome (survivors vs. non survivors). The OG had higher haptoglobin (34.8±14.2 mg/dL vs 20.8±7.21 mg/dL) and transferrin (487±161 mg/dL vs 369±71.4 mg/dL) values and lower iron (96.9±65 µg/dL vs 218±105 µg/dL) values than the CG. The OG horses with large intestine obstruction had lower values of transferrin (374.6±130 mg/dL) than horses with small intestinal obstruction (598.6±98.9 mg/dL). There was no difference in outcome between horses with large and small intestinal obstruction. Ferritin levels were moderately correlated with total protein (r = 0.594; P = 0.042) and albumin (r = 0.584; P = 0.046) in OG. In the multivariate exploratory analysis, fibrinogen levels were higher in animals that did not survive. In conclusion, haptoglobin, transferrin and iron were useful inflammatory markers for colic in horses. The correlation of ferritin with other APPs shows a possible role of ferritin as an APP in horses. Fibrinogen levels are higher in horses with greater risk of death from strangulating obstructions.

Effect of Procaine Penicillin G and Flunixin Meglumine on Serum Amyloid A Response in Healthy Adult Horses

This study was designed to determine the effect of PPG and/or flunixin meglumine on SAA response when used at clinical dosing regimens in healthy adult horses. Six healthy adult horses were enrolled in a crossover study design including one control and three treatment groups: no treatment (control); PPG alone (intramuscularly q12h for 72h); flunixin meglumine alone (intravenously q24h for 72h); and PPG (intramuscularly q12h for 72h) and flunixin meglumine (intravenously q24h for 72h). Whole blood was collected at 0, 24, 48, 72, 96 and 120 hours post-initial drug administration to measure SAA using a commercial lateral-flow immunoassay. The washout period was 30 days. Individual SAA values were within the reference range (≤ 20 µg/mL) for almost all horses in the control group. One control horse displayed a SAA value of 28 µg/mL at 72 hours. All horses from the PPG group showed normal SAA values throughout the study. Apart from one horse (SAA of 24 µg/mL at 96 hours) from the flunixin meglumine group, all horses showed normal SAA values. For the PPG and flunixin meglumine group, 5 horses had SAA values within reference range. One horse displayed increased SAA values (32-45 µg/mL) between 48 to 96 hours post-drug administration. There was no difference in area under the SAA time curve amongst control and treatment groups (P > 0.05). The administration of intramuscular PPG and/or intravenous flunixin meglumine does not trigger an inflammatory response that induces a SAA value above reference range in most adult healthy horses.

Acute phase protein concentrations following serial procaine penicillin G injections in horses

BACKGROUND

Acute phase protein (APP) measurement is used to detect inflammation. Intramuscular (IM) injections could cause tissue injury and induce an acute phase response (APR).

OBJECTIVES

To evaluate the effects of IM procaine penicillin G (PPG) injections on APP concentrations in horses.

STUDY DESIGN

Prospective longitudinal design.

METHODS

PPG was administered intramuscularly to six horses, twice daily, for 5 days. Plasma fibrinogen (FIB), serum amyloid A (SAA), haptoglobin (HAP), creatine kinase (CK), and aspartate aminotransferase (AST) were quantified daily for 5 days before the first injection, during the course of administration, and for 4 days after the final dose. Analytes were quantified every other day for the remaining 16 days. Data were compared using a parametric or non-parametric repeated measures ANOVA and a Tukey's or Mann-Whitney rank sum test, respectively. Significance was set at p < 0.05.

RESULTS

CK was increased over baseline (mean ± SD: 200 ± 74 IU/L) on Days 1-6 (p < 0.001 to p = 0.02, mean ± SD: 723-1177 ± 355-544 IU/L) and AST was increased above baseline (mean ± SD: 233 ± 58 IU/L) on Days 2-7 and 10 (p < 0.001 to p = 0.05, mean ± SD: 307-437 ± 79-146 IU/L). Increased FIB was noted over baseline (mean ± SD: 177 ± 30 mg/dl) on Days 6-8 and 10 (p = 0.02 to p = 0.03, mean ± SD: 234-252 ± 33-49 mg/dl). SAA was increased above baseline (mean ± SD: 4.7 ± 2.9) on Day 6 (p = 0.02, mean ± SD: 113 ± 186 μg/ml). There was no change in HAP.

MAIN LIMITATIONS

Healthy horses were used, small sample size, and a lack of a negative control group.

CONCLUSIONS

Serial intramuscular procaine penicillin G (IM PPG) injections may result in increased positive APP concentrations in horses and this must be considered when these test results are interpreted.

Pain Assessment and Acute Phase Response in Donkeys Submitted to Inguinal Orchiectomy

In most animals, pain can compromise physiological functions and delay healing so, rapid detection of pain through behavior and inflammatory reaction with biomarkers are necessary. This study aimed to evaluate pain, physiological variations and Acute Phase Proteins (APP) in donkeys undergoing orchiectomy technique by inguinal access. For this research, 15 male northeastern donkeys kept in extensive management were selected, with a mean age of 4.5±3.1 years. All animals had the same anesthetic protocol, using dissociative anesthesia and local block with lidocaine, followed by orchiectomy by inguinal access. Due to their predisposition to complications, the inguinal technique is the most indicated to minimize complications and excessive inflammation in donkeys' orchiectomy, the donkeys were evaluated regarding behavioral assessment of pain, hematological parameters, APP and the surgical wound, during 0 hour, 24 hours, 48 hours and 72 hours. As for the physiological parameters and APP, no significant differences were observed between times, due to the use of nonsteroidal antiinflammatory drugs. In the macroscopic evaluation of the surgical wound, it was observed that there were no significant differences between the times, with animals presenting mean scores of 1.8±0.414, in 48 hours 1.6 ± 0.507, and in 72 hours 1.6 ± 0.507. Most animals had mild to moderate edema in the scrotum and foreskin regions. As for pain assessment, the average scores were between 2 and 3, representing mild and moderate pain, not requiring intervention. However, further research is needed to elucidate the behavior of PFAs in the face of variables and the creation of new pain scales for animals raised in an extensive system.

Spontaneous Sepsis in Adult Horses: From Veterinary to Human Medicine Perspectives

Sepsis is a life-threatening disease defined as an organ dysfunction caused by a dysregulated host response to an infection. Early diagnosis and prognosis of sepsis are necessary for specific and timely treatment. However, no predictive biomarkers or therapeutic targets are available yet, mainly due to the lack of a pertinent model. A better understanding of the pathophysiological mechanisms associated with sepsis will allow for earlier and more appropriate management. For this purpose, experimental models of sepsis have been set up to decipher the progression and pathophysiology of human sepsis but also to identify new biomarkers or therapeutic targets. These experimental models, although imperfect, have mostly been performed on a murine model. However, due to the different pathophysiology of the species, the results obtained in these studies are difficult to transpose to humans. This underlines the importance of identifying pertinent situations to improve patient care. As humans, horses have the predisposition to develop sepsis spontaneously and may be a promising model for spontaneous sepsis. This review proposes to give first an overview of the different animal species used to model human sepsis, and, secondly, to focus on adult equine sepsis as a spontaneous model of sepsis and its potential implications for human and veterinary medicine.

Acute phase proteins levels in horses, after a single carbohydrate overload, associated with cecal alkalinization

Introduction

Horses submitted to carbohydrate overload can develop laminitis due to changes in cecal pH and microbiota, followed by an increase in transmural absorption of luminal content, including bacterial toxins. In response to acute injury there is hepatic overproduction of several proteins known as acute phase proteins (APP). Few studies have evaluated protein fractionation to characterize the inflammatory response in acute laminitis. The aim of this study was to test the viability of an experimental model to induce acute laminitis, using a single carbohydrate overload, and the influence of a buffering solution on the development of the disease; also, study the kinetics of APP during acute laminitis, as well as the correlation between these proteins and clinical signs associated to this syndrome.

Methods

Ten healthy horses were divided in a factorial and randomized way into four groups (n = 5): control group (CG), starch group (SG), buffer group (BG), and starch C buffer group (SBG). They were evaluated at seven times (T0h, T4h, T8h, T12h, T24h, T48h, and T72h), which included clinical evaluation and blood sample collection. Total serum protein and albumin concentrations were determined by colorimetry and the other APP by polyacrylamide gel electrophoresis containing sodium dodecyl sulfate and commercial ELISA kits. Data were analyzed by two-way ANOVA, followed by Tukey's test (p < 0.05). The correlation between clinical signs and APP were verified using the Pearson's correlation coefficient.

Results and discussion

40% of the animals from SG and 60% from SBG developed clinical laminitis. A single administration of buffer solution was not able to prevent clinical signs of laminitis. There was no difference between groups on total serum protein, albumin, serum amyloid A and C-reactive protein concentrations (p > 0.05). Transferrin, considered a negative APP, showed a positive response pattern in SG and SBG. Ceruloplasmin had a positive correlation with Obel grade, heart rate on animals from SGB and number of steps on horses submitted to starch overload (SG and SBG). Ceruloplasmin, α-1-antitrypsin and haptoglobin concentrations increased in SBG, suggesting an inflammatory response in animals of this group. Changes in clinical parameters were also more evident in the SBG, corroborating the protein fractionation findings.

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.

Serum amyloid A and fibrinogen as markers for early detection of surgical site infection associated with internal fixation in the horse

The objective of this study was to determine the diagnostic ability of serum amyloid A (SAA) and fibrinogen for early detection of surgical site infection (SSI) after equine internal fixation. Horses undergoing internal fixation for fracture, arthrodesis, or osteotomy with internal fixation for limb deformity were included in the study. SAA and fibrinogen were measured on blood samples preoperatively and on days 1, 3, 5, 7, 10, and 14 postoperatively. Statistical analysis included use of Spearman's rank correlation, logistic regression, and calculating the area under the receiver operating characteristic (ROC) curve. SAA and fibrinogen measurements were both associated with SSI, with SAA being considered an excellent marker (area under the ROC curve 0.8) and fibrinogen being considered acceptable (<0.8). As the amount of time postoperatively increased, SAA elevations indicated a higher likelihood of SSI (area under the ROC curve 0.8 compared with fibrinogen 0.7). SAA and fibrinogen were predictive markers of SSI and SAA is of greater diagnostic utility when compared with fibrinogen. Persistent elevations of SAA postoperatively are associated with the development of SSI. Serial monitoring of SAA can be used to help predict the development of SSI in horses undergoing internal fixation. This may lead to earlier suspicion, and therefore recognition and treatment of SSI.

Serum proteins and electrophoretic profile in horses undergoing crotalid venom hyperimmunization

Indisputably, the use of antivenoms for the treatment of snakebite envenoming is beneficial for the victims. However, there are few studies addressing the effect of long-term hyperimmunization in inoculated horses. It is known that the injection of snake venoms and adjuvants leads to local and systemic reactions in horses, but little is known about the response of inflammatory proteins. The aim of this study was to evaluate serum proteins and the electrophoretic profile of horses undergoing crotalid venom hyperimmunization. Twenty horses were divided into two groups: an inoculated group, comprising ten horses that were already being used for production of a Crotalus sp. antivenom, and a control group, comprising ten animals that had never been used for hyperimmunization. All animals were clinically healthy and without laboratory abnormalities. Total protein and albumin concentrations were measured in serum. Serum globulins were obtained by calculation. Plasma fibrinogen estimates were determined by the heat precipitation method. Serum proteinograms were obtained using agarose gel electrophoresis. The results revealed a significant increase in the concentrations of total serum proteins, globulins, and β-globulins in the inoculated group, exceeding the reference values. There were slight increases in the α-1- and α-2-globulin subfractions in serum-producing horses, with no statistical significance. We also observed that horses used to produce hyperimmune plasma developed hypoalbuminemia, although the decrease in albumin production was not statistically significant. Our findings suggest that the continuous use of horses to produce crotalid antivenom may lead to a chronic inflammatory stimulus, with changes in plasma levels of inflammatory proteins.

Using systemic serum amyloid A as a biomarker for synovial structure infections in horses with acute limb wounds

BACKGROUND

In postoperative monitoring of synovial structure infection due to limb wounds, early recognition of a recurrence of synovial infection is indispensable to prevent further damage to the affected synovial structure. This study evaluated the role of serum amyloid A (SAA) as a systemic biomarker in disease monitoring and correlated this tool with clinical variables.

METHODS

In this prospective cohort study, 55 horses with acute limb wounds were divided into two groups: those with (group 1, n = 26) or without (group 2, n = 29) a diagnosis of synovial structure penetration. SAA, lameness and body temperature were evaluated repeatedly and compared between groups. Correlations were explored between SAA and body temperature as well as lameness. The long-term outcome was also analysed.

RESULTS

In both groups, SAA levels followed the characteristic rise-and-fall pattern observed in previous studies, with a significant increase up to a peak concentration within 48 hours, followed by a constant decline. Lameness and body temperature did not change significantly. SAA was not found to correlate with clinical variables at all time points. Three horses in group 1 had a recurrence of synovial sepsis with an associated increase in SAA. The long-term outcome was good. A total of 71% of the study population returned to pre-injury performance levels.

CONCLUSION

Repeated measurements of SAA accurately reflected the course of synovial inflammation and thus provided a reliable and rapidly available tool to monitor the disease course and to adapt the treatment regimen. SAA should be routinely added to the postoperative management of such cases.

Usefulness of Selected Acute-Phase Proteins in the Postsurgical Monitoring of Arthroscopy and Splint Bone Removal in Horses

Simple Summary

The study shows the changes in concentration of acute phase proteins (fibrinogen, haptoglobin, protease inhibitors) in the serum of patients from the equine clinic. Blood was collected from horses that underwent arthroscopy (41 horses) and splint bone removal (13 horses). The concentration of the above-mentioned proteins was recorded from the time before the surgery until the 28th day after the surgery and compared to a control group of healthy horses (60 horses). Acute phase proteins change their concentration before clinical symptoms appear; therefore, they could play a key role in early recognition and preventing complications.

Abstract

Background: Arthroscopy and splint bone removal are the common orthopedic procedures in horses. Estimation of the dynamics of acute phase proteins in postoperative monitoring seems to be interesting diagnostic approach. The aim of the study was to investigate changes in the concentrations of plasma inflammatory markers—fibrinogen, haptoglobin, and protease inhibitors—following orthopedic surgery in horses. The study involved 114 horses, divided into two study groups undergoing: arthroscopy (41 horses) and splint bone removal (13 horses). The control group consisted of 60 healthy horses. The blood was collected before the surgery and 24, 48, 72 h, 5, 7, 10, 14 and 28 days after the surgery. Plasma fibrinogen, serum haptoglobin and proteinase inhibitors were measured. Results: In non-complicated cases of arthroscopy and splint bone removal, fibrinogen and haptoglobin increased stepwise from 24 h, achieved the maximum level at 72 h and returned to preoperative levels after 10–14 days. In one complicated case after arthroscopy surgery the marked increase in fibrinogen and haptoglobin concentrations was observed 24 h earlier than standard parameters of inflammation Conclusion: The study shows the evolution of APPs after arthroscopy and splint bone removal in 28 days postsurgery period and in the case of one complicated case of arthroscopy.

Systemic serum amyloid A in early (<24 h) diagnosis of acute synovial structure involvement in horses with penetrating limb injuries

Synovial structure involvement secondary to limb injury is a common emergency in equine practice, requiring an accurate initial diagnosis for immediate treatment. This study aimed to investigate the clinical usefulness of Serum amyloid A (SAA) in the initial diagnosis of synovial structure involvement caused by acute (<24 h) penetrating limb injuries in horses and to correlate SAA with standard diagnostic parameters. Fifty-five horses with acute limb injuries were divided into two groups: Group 1 (G1, n = 26) with a diagnosis of penetrating synovial trauma and Group 2 (G2, n = 29) without synovial structure penetration. Serum SAA, white blood cell (WBC) count and fibrinogen as well as clinical criteria and synovial fluid parameters were assessed on admission. The two groups were compared using a two-sample t-test (metric parameters) or a Wilcoxon-Mann-Whitney test (ordinal parameters). Correlation was determined between serum SAA and the following parameters: WBC count, fibrinogen, synovial total nucleated cell count (TNCC) and percentage of neutrophils (% N), body temperature and the degree of lameness. Serum SAA concentrations were not different between G1 and G2; however, there were statistically significant differences in general health, the degree of lameness, and synovial fluid parameters. In G1, serum SAA concentrations positively correlated with fibrinogen concentrations and synovial fluid % N. Nonetheless, SAA cannot be used as a sole tool to diagnose synovial structure involvement caused by limb injuries. Synovial fluid parameters remain the most important tool in the diagnosis of synovial penetration. In cases where synoviocentesis fails or is not possible, serum SAA might support diagnosis.

The relationship of metabolic parameters and milk acute-phase protein with the outcome of treatment of Staphylococcus aureus subclinical mastitis in dairy cows

The main aim of the current investigation was to evaluate the relationships between metabolic parameters, acute-phase proteins, and the outcome of treatment of Staphylococcus aureus subclinical mastitis in dairy cows. Serum metabolic parameters and milk haptoglobin were measured in two groups: S. aureus subclinical mastitis cows with successful treatment (n = 26) and S. aureus subclinical mastitis cows with unsuccessful treatment (n = 26). Significantly higher serum aspartate aminotransferase (AST), alkaline phosphatase (ALP), and LDL cholesterol concentrations were seen in subclinical mastitis cows with unsuccessful treatment compared to subclinical mastitis cows with successful treatment (p < 0.05). On the other hand, subclinical mastitis cows with successful treatment demonstrated higher serum iron and copper concentrations than the other group (p < 0.05). Comparison of measured variables before treatment revealed that cows suffering from subclinical mastitis with higher values of serum LDL cholesterol, ALP, and AST did not respond to antibiotic treatment and subclinical mastitis was persisted in the second examination, whereas subclinical mastitis cows with successful treatment demonstrated higher serum copper and iron concentrations (p < 0.05). The findings of the current investigation suggested that there was a relationship between the treatment outcome of S. aureus subclinical mastitis and trace element concentrations and liver health status. Furthermore, the present study provided cutoff values for serum LDL cholesterol, AST, ALP, iron, and copper, which would help predict the treatment outcome in cows with S. aureus subclinical mastitis.

Dietary supplementation of a Saccharomyces cerevisiae fermentation product attenuates exercise-induced stress markers in young horses

Mitigation of exercise-induced stress is of key interest in determining ways to optimize performance horse health. To test the hypothesis that dietary supplementation of a Saccharomyces cerevisiae fermentation product would decrease markers of exercise-induced stress and inflammation in young horses, Quarter Horse yearlings (mean ± SD; 9 ± 1 mo) were randomly assigned to receive either no supplementation (CON; n = 8) or 21 g/d S. cerevisiae fermentation product (10.5 g/feeding twice daily; SCFP; n = 10) top-dressed on a basal diet of custom-formulated grain as well as ad libitum Coastal bermudagrass hay. After 8 wk of dietary treatments, horses underwent a 2-h submaximal exercise test (SET) on a free-stall mechanical exerciser. Serum was collected before dietary treatment supplementation (week 0), at week 8 pre-SET, and 0, 1, and 6 h post-SET and analyzed for concentrations of cortisol and serum amyloid A (SAA) by commercial enzyme-linked immunosorbent assay (ELISA) and for cytokine concentrations by commercial bead-based ELISA. Data were analyzed using linear models with repeated measures in SAS v9.4. From week 0 to 8 (pre-SET), serum cortisol decreased (P = 0.01) and SAA did not change, but neither were affected by diet. Serum concentrations of all cytokines decreased from week 0 to 8 (P ≤ 0.008), but granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor, and interleukin-8 (IL-8) decreased to a greater extent in CON than in SCFP horses (P ≤0.003). In response to the week 8 SET, serum cortisol increased in all horses (P < 0.0001) but returned to pre-SET levels by 1 h post-SET in horses receiving SCFP. At 6 h post-SET, cortisol concentrations in CON horses returned to pre-SET concentrations, whereas cortisol declined further in SCFP horses to below pre-SET levels (P = 0.0002) and lower than CON (P = 0.003) at that time point. SAA increased at 6 h post-SET in CON (P < 0.0001) but was unchanged through 6 h in SCFP horses. All cytokines except G-CSF increased in response to the SET (P < 0.0001) but showed differing response patterns. Concentrations of IL-1β, IL-6, and tumor necrosis factor-alpha were lesser (P ≤ 0.05), and concentrations of G-CSF and IL-18 tended to be lesser (P ≤ 0.09) in SCFP compared with CON horses throughout recovery from the SET. In summary, 8 wk of dietary supplementation with 21 g/d of SCFP may mitigate cellular stress following a single, prolonged submaximal exercise bout in young horses.

Inflammatory response of miniature horses subjected to open and half-closed orchiectomy techniques

BACKGROUND

This study aimed to evaluate the inflammatory response of miniature horses subjected to open and half-closed orchiectomy by physical examination, blood cell count, peritoneal fluid evaluation, total plasma protein, fibrinogen, and serum amyloid A (SAA) concentrations.

METHODS

Thirteen male healthy miniature horses were divided into two groups, according to the surgical approach: half-closed technique (HCT) and open technique (OT). The HCT group was subjected to ligation of the spermatic cord followed by its sharp incision, and closure of the vaginal tunic, and the OT group was only submitted to cord ligation. Prior to, and at 1, 2, 3 and 5 days after the surgery, a general and specific physical examination, blood cell counts, total plasma protein, peritoneal fluid evaluation, fibrinogen, and SAA concentrations were performed.

RESULTS

Higher postoperative perilesional oedema, rectal temperature, and fibrinogen were observed in the HCT group. Groups did not differ as to SAA concentrations. The evaluated local and systemic inflammatory profile demonstrated that, as expected, surgery resulted in inflammation in both groups.

CONCLUSIONS

The group subjected to the HCT showed a more intense and lasting inflammatory response. However, despite the different postoperative inflammatory profiles, both groups presented a favourable outcome and recovery.

The Accuracy of Serum Amyloid A in Determining Early Inflammation in Horses After Long-Distance Transportation by Air

Transportation of sporthorses increases their susceptibility to infectious diseases. Before, caretakers relied on rectal temperature together with their clinical impression to detect travel-associated infections. This study's aim was to assess and compare serum amyloid A (SAA) to rectal temperature as an indicator of early inflammation in sporthorses after air transportation. One hundred and twenty-two Warmblood horses were followed during the Longines Global Champions Tour 2016 to three destinations where the horses flew to compete. Clinical health checks and SAA measurements were performed before flying, upon arrival (0 hours), and 24 hours postarrival. Serum amyloid A was tested using a stall-side lateral flow immunoassay. Rectal temperature was measured twice a day using a commercially available digital thermometer. An SAA cutoff value of 23 μg/mL measured 24 hours postarrival was able to correctly distinguish between a healthy and sick horse with a sensitivity and specificity of 93.3% and 91.3%, respectively. Conversely, elevated rectal temperature had a sensitivity of only 3% to distinguish between the two horse groups. Monitoring SAA in traveling sporthorses is a more sensitive indicator of clinical health than monitoring body temperature and may aid in early identification of inflammatory processes.

Effects of Flunixin Meglumine, Firocoxib, and Meloxicam in Equines After Castration

This study is "aimed" to evaluate and compare the efficacy of flunixin meglumine (FM), firocoxib (FX), and meloxicam (MX) after castration of horses. Thirty horses were submitted to open castration and divided into three groups (n = 10) depending on the anti-inflammatory drug administered: group I (GI) (FM, 1.1 mg kg¹, IV, once a day [SID], 5 days); group II (GII) (FX, 0.1 mg kg¹, IV, SID, 5 days), and group III (GIII) (MX, 0.6 mg kg¹, IV, SID, 5 days). Clinical, behavioral, and hematological parameters and the peritoneal fluid (PF) were evaluated before (day [D] 0) and 1, 2, 3, 5, and 7 days afterward. In the postoperative, scores of limb rigidity and prepuce edema of animals of GII and GIII were greater than those of GI. Tachycardia was observed in the horses of GII and GIII and hyperthermia in GIII. An increase in the number of leukocytes, neutrophils, and monocytes without exceeding the reference values and hyperfibrinogenemia was observed in the animals of GI (D7), GII (D1-D7), and GIII (D7). There was reduction in serum protein after castration, together with an increase of this in the PF of the animals of the three groups. The PF on D0 was straw yellow and limpid, became reddish and cloudy on D1, and then gradually moved toward its normal color on the ensuing days, but without returning to normal on D7 in any of the groups. The results showed that castration triggers significant clinical and laboratory changes and that FM, FX, and MX are equally effective in controlling pain and inflammation in horses after castration; however, FM was more advantageous.

Effects of equine metabolic syndrome on inflammation and acute-phase markers in horses

Obesity and metabolic disorders are associated with systemic low-grade chronic inflammation, both in humans and animals. The aim of the study is to assess the effects of obesity and hyperinsulinemia on individual components of the acute-phase reaction in equine metabolic syndrome (EMS) horses. Eight mixed-breed EMS and six control, age-matched horses of both sexes were included in the study. Animals were classified as EMS or control based on the assessment of BCS, cresty neck score, and basal insulin >50 μU/mL and/or insulin responses to the oral sugar test (OST) >60 μU/mL. Peripheral venous blood was collected. The expression of proinflammatory cytokines, the concentration of circulating cytokines, and acute-phase proteins (serum amyloid A, C-reactive protein, haptoglobin, activin A, and procalcitonin) were measured. The data were analyzed using the Mann-Whitney test, whereas correlations were examined using Spearman's correlation coefficient. The tests were statistically significant if P ≤ 0.05. There were no differences in cytokine gene expression, circulating cytokine concentrations, or concentrations of acute-phase proteins between the EMS and the control groups. There was a strong correlation between the basal concentration of insulin and the serum concentrations of IL-6 (r = 0.71, P < 0.05). Activin A was positively correlated with post-OST insulin concentrations (r = 0.707, P = 0.05), indicating that this marker of inflammation could warrant further investigation in horses with EMS.

Serum Amyloid A (SAA) Concentration after Vaccination in Horses and Mules

Serum amyloid A (SAA) is a sensitive acute-phase response (APR) marker in equids. Prominent APRs with elevations of SAA concentrations ([SAA]) have been reported after vaccination. The authors hypothesized that vaccination with an inactivated EHV-1/-4 vaccine would cause increase in [SAA] and antibody responses and that higher [SAA] would be positively correlated with the antibody titer in both equids. Twelve Haflinger horses and 12 mules were included in this longitudinal prospective study. All horses and mules were vaccinated with a commercially available EHV-1/-4 vaccine. Blood was sampled before and after vaccination to measure [SAA] and virus-neutralizing response (VN-T). In horses and mules, significantly higher [SAA] were measured on days 1, 3, and 5 after EHV-1/-4 vaccination; [SAA] on day 1 after vaccination were only measured in animals that developed fever, where mean [SAA] were significantly higher in horses than in mules (horses: 1,365.75 ± 87.64 mg/L, mules: 615.5 ± 153.444 mg/L) (P > .05). Four horses and 2 mules developed fever after vaccination, lasting for ≤24 hours. Increased antibody responses (VN-T) on days 7 and 14 after vaccination were observed in all animals, whereas mules showed higher overall antibody responses. Nevertheless, [SAA] did not correlate with the intensity of the antibody responses (VN-T) stimulated by the vaccine (P < .05). EHV-1/-4 vaccination caused a prominent APR, higher in horses than in mules, but [SAA] did not correlate with antibody responses. Measuring [SAA] after vaccination could help identify severe APRs that may require longer resting intervals before training or competition.

The influence of equine body weight gain on inflammatory cytokine expressions of adipose tissue in response to endotoxin challenge

Background

Human obesity is linked with systemic inflammation. However, it is still controversial if equines produce more inflammatory cytokines with increasing body weight and if the production of those show breed type specific patterns. The main objective of this study was to determine if diet induced obesity is associated with increased inflammatory signatures in adipose tissue of equines and if a breed predisposition exists between ponies and horses. Additionally, we aimed to identify adipose tissue depot differences in inflammatory cytokine expression. Nineteen healthy, non-overweight and metabolically healthy equines received a hypercaloric diet for 2 years. Body weight, body condition score and cresty neck score were assessed weekly throughout the study. At three time points, insulin sensitivity was determined by a combined glucose-insulin test. Adipose tissue samples were collected from two intra-abdominal and two subcutaneous depots under general anesthesia at each time point after an endotoxin trigger. In the adipose tissue samples levels of CD68 mRNA (a marker of macrophage infiltration) and pro-inflammatory cytokine mRNA (IL-1β, IL-6 and TNFα) were analyzed with RT-qPCR. As markers of lipid metabolism mRNA levels of lipoprotein lipase (LPL) and fatty acid binding protein 4 (FABP4) were determined with RT-qPCR.

Results

CD68 mRNA levels increased with body weight gain in several adipose tissue (AT) depots (Wilcoxon signed rank test with Bonferroni correction; retroperitoneal AT horses: P = 0.023, mesocolonial AT horses: P = 0.023, subcutaneous tail head AT ponies: P = 0.015). In both abdominal depots CD68 mRNA levels were higher than in subcutaneous adipose tissue depots (Kruskal–Wallis-ANOVA with Bonferroni correction: P < 0.05). No breed related differences were found. Pro-inflammatory cytokine mRNA IL-1β, IL-6 and TNFα levels were higher in subcutaneous depots compared to abdominal depots after body weight gain. IL-1β, IL-6 and TNFα mRNA levels of mesocolon adipose tissue were higher in obese horses compared to obese ponies (Mann–Whitney-U test; IL-1β: P = 0.006; IL-6: P = 0.003; TNFα: P = 0.049). In general, horses had higher FABP4 and LPL mRNA levels compared to ponies in neck AT and tail AT at all time points.

Conclusion

Our findings suggest an increased invasion of macrophages in intra-abdominal adipose tissue with increasing body weight gain in equines in combination with a low dose endotoxin stimulus. This might predispose equines to obesity related comorbidities. In obese horses mesocolon adipose tissue showed higher inflammatory cytokine expression compared to obese ponies. Additionally, subcutaneous adipose tissue expressed more pro-inflammatory cytokines compared to intra-abdominal adipose tissue. Horses had higher FABP4 and LPL mRNA levels in selected AT depots which may indicate a higher fat storage capacity than in ponies. The differences in lipid storage might be associated with a higher susceptibility to obesity-related comorbidities in ponies in comparison to horses.

Inflammatory Response of Healthy Horses Subjected to Small Colon Enterotomy and Treated or Not With Heparin

The acute phase response is a response to injury and depends on the severity of the trauma. Heparin is routinely used for postsurgical treatment of horses to prevent abdominal adhesions; however, its effect on inflammation is unknown. This study aimed to assess systemic inflammatory response of horses subjected to small colon enterotomy and to evaluate heparin effects on postsurgical inflammation. Ten adult horses were subjected to small colon enterotomy and were assigned to a control or a treatment group. Both groups received prophylactic antibiotics and flunixin, and the treatment group received 150 IU/kg heparin subcutaneously after surgery and every 12 hours for five days. WBC counts, peritoneal fluid evaluation, determination of serum and peritoneal haptoglobin (Hp), and serum amyloid A (SAA) were performed before, 12 hours, and 1, 2, 4, 6, 10, and 14 days after enterotomy. Forty-eight hours after surgery, a significant increase in serum Hp was observed in the control group, and SAA concentrations increased significantly in the both groups between 24 hours, 48 hours, and 4 days after surgery. The SAA and serum Hp concentrations produced no significant differences between the groups. Peritoneal Hp increased significantly in the control group 4 days after surgery and was significantly higher in the control group than in the treated group 14 days after surgery. Serum Hp and SAA identified the acute phase response changes faster, however, were not able to identify differences between groups. Peritoneal Hp concentrations identified inflammatory differences between the groups 14 days after surgery; the difference suggests that heparin may act decreasing inflammation.

Can blood serum amyloid A concentrations in horses differentiate synovial sepsis from extrasynovial inflammation and determine response to treatment?

Background

Serum amyloid A (SAA) concentrations in blood and synovial fluid of horses with synovial sepsis have diagnostic value. Studies suggest serial blood SAA measurements could act as a prognostic indicator. This study evaluated the use of serial blood SAA concentrations for monitoring of horses with synovial sepsis.

Methods

A prospective clinical trial was performed of horses referred to a single hospital with synovial sepsis that survived (n=17), synovial sepsis that were euthanised (n=5), non-septic intrasynovial pathologies (n=14) or extensive extrasynovial lacerations (n=5). SAA concentrations were determined on admission and every 24 hours thereafter. The area under the concentration–time curve from 0 to 144 hours of each group was compared by Kruskal-Wallis and post hoc Dunn’s tests (P<0.05).

Results

Significant difference in mean blood concentration of SAA was found between synovial sepsis that survived and non-septic pathologies in the first 48 hours, as well as between non-septic intrasynovial pathologies and non-responsive sepsis requiring euthanasia. No difference was found between extensive extrasynovial lacerations and any septic group.

Conclusions

While serial blood SAA is useful for monitoring clinical response of intrasynovial septic pathologies, interpretation should consider other clinical findings since blood SAA is not a specific marker for synovial sepsis.

The Effect of Sedation, Oral Examination, and Odontoplasty on Systemic Inflammation as Measured by Serum Amyloid A in the Adult Performance Horse

Serum amyloid A (SAA) is one of the major acute phase proteins in horses. It serves as a marker for systemic inflammation and infection, as the concentration can increase 100- to even 1000-fold during systemic disease processes. The objective of this study was to evaluate the effect of sedation, oral examination, and odontoplasty on systemic inflammation as measured by SAA in the adult performance horse. This study included 32 clinically healthy adult performance horses. Blood samples were collected immediately prior to sedation, oral examination, and odontoplasty and 48 and 72 hours afterward. Serum amyloid A levels were measured directly after venipuncture using a commercially available stall-side lateral flow immunoassay test developed and validated for equine SAA levels. Serum amyloid A values were within normal limits for each of the time periods and there were no significant differences in SAA values between the time periods. The results of this study suggest that sedation, oral examination, and odontoplasty have no systemic inflammatory effects as measured by SAA.

Assessment of the Acute Phase Response in Healthy and Injured Southern White Rhinoceros (Ceratotherium simum simum)

Acute phase reactants (APRs) have not been investigated in white rhinoceros (Ceratotherium simum). This study aimed to identify clinically useful APRs in this species. Reference intervals (RIs) were generated for albumin, fibrinogen, haptoglobin, iron and serum amyloid A (SAA) from 48 free-ranging animals, except for SAA (n = 23). APR concentrations between healthy animals and those with tissue injury (inflammation) (n = 30) were compared. Diagnostic performance was evaluated using receiver-operator characteristic (ROC) curve and logistic regression analyses. RIs were: albumin 18–31 g/L, fibrinogen 1.7–2.9 g/L, haptoglobin 1.0–4.3 g/L, iron 9.7–35.0 μmol/L, SAA <20 mg/L. Iron and albumin were lower and fibrinogen, haptoglobin and SAA higher in injured vs. healthy animals. Iron showed the best diagnostic accuracy followed by fibrinogen, albumin, haptoglobin and SAA. Iron ≤ 15.1 μmol/L and haptoglobin >4.7 g/L were significant predictors of inflammatory status and together correctly predicted the clinical status of 91% of cases. SAA > 20 mg/L had a specificity of 100%. In conclusion, albumin and iron are negative and fibrinogen, haptoglobin and SAA positive APRs in the white rhinoceros. The combination of iron and haptoglobin had an excellent diagnostic accuracy for detecting inflammation.

Validation of an equine serum amyloid A assay with an unusually broad working range

Background

Serum amyloid A (SAA) is a major equine acute phase protein and of great value in detection and monitoring of inflammation. A new immunoturbidometric assay based on monoclonal antibodies (VET-SAA, Eiken Chemical Co., Japan) may be useful for SAA measurements in routine diagnostic laboratories. The aim of the study was to validate the VET-SAA immunoturbidometric assay and use it to measure serum SAA concentrations in a variety of clinical cases. Precision was assessed by intra- and interassay coefficients of variation of repeated measurements of serum pools (low, intermediate, high concentrations of SAA). Accuracy was estimated by linearity under dilution. Detection limit was determined by replicate determinations of ionized water. Measurements were compared to measurements performed in a previously validated SAA assay (LZSAA assay, Eiken Chemical Co., Japan). Subsequently, the VET-SAA assay was used for measuring serum SAA concentrations in horses with and without inflammation.

Results

Detection limit was 1.2 mg/L. Without modifications, the assay measured SAA concentrations with acceptable reliability in a broad concentration range (0 to > 6000 mg/L). In the 0–3000 mg/L range, the assay demonstrated good precision and accuracy, and concentrations correlated well with those obtained in the LZSAA assay, albeit with a slight systematic bias. Concentrations of SAA assessed in horses with and without inflammation followed the expected pattern, with significantly higher concentrations in horses with systemic inflammation than in healthy horses and horses with non-inflammatory disease.

Conclusions

The assay was unique in its ability to measure SAA concentrations with acceptable reliability over an extreme concentration range. This is relevant in the equine species, where SAA concentrations may reach very high concentrations.

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

BACKGROUND

Acute-phase proteins may help assess the nature and severity of lesions and outcome in horses undergoing colic surgery.

OBJECTIVES

To compare serum amyloid A and plasma fibrinogen concentrations ([SAA] and [fibrinogen]) in the immediate post-operative period after exploratory celiotomy and determine their value in assessment of post-operative complications and survival to discharge.

STUDY DESIGN

Observational study.

METHODS

This study included horses over 1 year of age undergoing exploratory celiotomy. Surgical procedures, lesions, post-operative care, complications and survival to discharge were recorded. [SAA] and [fibrinogen] were measured prior to surgery and 5 days post-operatively. Statistical analyses included Yate's Chi-square test, linear mixed effects model, Mann-Whitney U test and logistic regression.

RESULTS

Of 300 horses, 52.0% developed post-operative complications and 83.7% survived to discharge, with significantly reduced chance of survival in horses that developed post-operative complications (P<0.01). Median [SAA] at days 1, 2, 3, 4 and 5 and median [fibrinogen] at days 3, 4 and 5 were significantly different between horses that did and did not develop post-operative complications (P<0.05). Median [SAA] at days 1, 4 and 5 were significantly different between horses that did and did not survive to discharge (P<0.05). Logistic regression revealed post-operative complications to be associated with strangulating lesions (OR 2.35, 95% confidence interval [CI] 1.41-3.91, P≤0.001) and higher [fibrinogen] at admission (OR 1.21, 95% CI 1.00-1.45, P<0.05), and survival to discharge to be associated with lower [SAA] at 5 days post-operatively (OR 0.965, 95% CI 0.94-0.99, P = 0.002).

MAIN LIMITATIONS

A large variety of lesions and complications prevented detailed analysis of associations between inflammatory markers, lesions and complications.

CONCLUSIONS

Horses that develop post-operative complications have acute-phase responses of greater magnitudes and durations compared with those that do not develop complications. This is also seen in horses that do not survive to discharge. Measuring [SAA] daily and [fibrinogen] at admission, may help predict the development of post-operative complications.

Evaluation of Systemic and Local Inflammatory Parameters and Manifestations of Pain in an Equine Experimental Wound Model

In the last decades, a well-established equine wound model has been used to study fibroproliferative wound healing disorders. The aim of this study was to characterize the degree of discomfort of wounding and sampling in an equine excisional wound model by evaluating systemic and local inflammatory responses and signs of pain. A total of 12 cutaneous wounds, three on each shoulder and each metatarsus, were created in a standing surgical procedure. Wounds were biopsied on days 2, 4, 7, 14, 21, and 28 after surgery. Clinical parameters (rectal temperature, heart rate, respiratory frequency) and blood levels of white blood cell, serum amyloid A, fibrinogen, and iron were monitored to evaluate the systemic inflammatory response. Local signs of inflammation (swelling, heat, pain) were subjectively assessed, the limb circumference recorded, and temperature of the wound measured by thermometry. Pain was evaluated by a composite measure pain scale (CMPS). The results demonstrated that the wounding procedure elicits an inflammatory response. Day 1 after surgery, two horses scored 2 and 7 units (of 27 units), respectively, on the CMPS, and day 8 after surgery, one horse scored 3 units. The biopsy procedure did not elicit local or systemic signs of inflammation. Based on these findings, it appears that the equine experimental wound model causes mild discomfort and pain manifestations. This information is important for researchers, who consider using the model. To justify the use of an animal model, it should be demonstrated that the expected benefits of the research outweigh the discomfort imposed to the animal.

Analytical validation of a new point-of-care assay for serum amyloid A in horses

BACKGROUND

Serum amyloid A (SAA) is a major acute phase protein in horses. A new point-of-care (POC) test for SAA (Stablelab) is available, but studies evaluating its analytical accuracy are lacking.

OBJECTIVES

To evaluate the analytical performance of the SAA POC test by 1) determining linearity and precision, 2) comparing results in whole blood with those in serum or plasma, and 3) comparing POC results with those obtained using a previously validated turbidimetric immunoassay (TIA).

STUDY DESIGN

Assay validation.

METHODS

Analytical validation of the POC test was done in accordance with American Society of Veterinary Clinical Pathology guidelines using residual equine serum/plasma and whole blood samples from the Clinical Pathology Laboratory at the University of California-Davis. A TIA was used as the reference method. We also evaluated the effect of haematocrit (HCT).

RESULTS

The POC test was linear for SAA concentrations of up to at least 1000 μg/mL (r = 0.991). Intra-assay CVs were 13, 18 and 15% at high (782 μg/mL), intermediate (116 μg/mL) and low (64 μg/mL) concentrations. Inter-assay (inter-batch) CVs were 45, 14 and 15% at high (1372 μg/mL), intermediate (140 μg/mL) and low (56 μg/mL) concentrations. SAA results in whole blood were significantly lower than those in serum/plasma (P = 0.0002), but were positively correlated (r = 0.908) and not affected by HCT (P = 0.261); proportional negative bias was observed in samples with SAA>500 μg/mL. The difference between methods exceeded the 95% confidence interval of the combined imprecision of both methods (15%).

MAIN LIMITATIONS

Analytical validation could not be performed in whole blood, the sample most likely to be used stall side.

CONCLUSION

The POC test has acceptable accuracy and precision in equine serum/plasma with SAA concentrations of up to at least 1000 μg/mL. Low inter-batch precision at high concentrations may affect serial measurements, and the use of the same test batch and sample type (serum/plasma or whole blood) is recommended. Comparison of results between the POC test and the TIA is not recommended.

Are serum amyloid A or D-lactate useful to diagnose synovial contamination or sepsis in horses?

Synovial sepsis in horses is life threatening and accurate diagnosis allowing prompt treatment is warranted. This study assessed the diagnostic value of serum amyloid A (SAA) and D-lactate in blood and synovial fluid (SF) as diagnostic markers of synovial sepsis in horses and correlated them with total nucleated cell count (TNCC), percentage of neutrophils (%N) and total protein (TP) in SF. Blood and SF SAA and D-lactate concentrations were determined in a case–control observational study including 112 horses (38 with synovial contamination or sepsis (SCS), 66 with non-septic intra-synovial pathology (NSISP) and 8 controls). Blood and SF SAA were significantly higher in SCS than in NSISP and control horses. SAA values were similar in NSISP and control horses. SF SAA was moderately correlated with synovial TNCC, TP and blood SAA. Blood and SF SAA were 82.4 per cent and 80 per cent sensitive and 88.9 per cent and 73 per cent specific for diagnosis of SCS, with cut-off values of 60.7 and 1.14 µg/ml, respectively. Blood and SF D-lactate concentrations were not significantly different between groups. This study shows that blood and SF SAA concentrations can aid to distinguish SCS from non-septic synovial pathology; however, D-lactate was not useful.

Course of serum amyloid A (SAA) plasma concentrations in horses undergoing surgery for injuries penetrating synovial structures, an observational clinical study

BACKGROUND

Injuries penetrating synovial structures are common in equine practice and often result in septic synovitis. Significantly increased plasma levels of serum amyloid A (SAA) have been found in various infectious conditions in horses including wounds and septic arthritis. Plasma SAA levels were found to decrease rapidly once the infectious stimulus was eliminated. The purpose of the current study was to investigate the usefulness of serial measurements of plasma SAA as a monitoring tool for the response to treatment of horses presented with injuries penetrating synovial structures. In the current study plasma SAA concentrations were measured every 48 hours (h) during the course of treatment.

RESULTS

A total of 19 horses with a wound penetrating a synovial structure were included in the current study. Horses in Group 1 (n = 12) (injuries older than 24 h) only needed one surgical intervention. Patients in this group had significantly lower median plasma SAA levels (P = 0.001) between 48 h (median 776 mg/L) and 96 h (median 202 mg/L) after surgery. A significant decrease (P = 0.004) in plasma SAA levels was also observed between 96 h after surgery (median 270 mg/L) and 6 days (d) after surgery (median 3 mg/L). Four horses (Group 2) required more than one surgical intervention. In contrast to Group 1 patients in Group 2 had either very high initial plasma concentrations (3378 mg/L), an increase or persistently high concentrations of plasma SAA after the first surgery (median 2525 mg/L). A small group of patients (n = 3) (Group 3) were admitted less than 24 h after sustaining a wound. In this group low SAA values at admission (median 23 mg/L) and peak concentrations at 48 h after surgery (median 1016 mg/L) were observed followed by a decrease in plasma SAA concentration over time.

CONCLUSIONS

A decrease in plasma SAA concentrations between two consecutive time points could be associated with positive response to treatment in the current study. Therefore, serial measurements of plasma SAA could potentially be used as an additional inexpensive, quick and easy tool for monitoring the treatment response in otherwise healthy horses presented with injuries penetrating synovial structures. However further studies will be necessary to ascertain its clinical utility.

The Effect of Different Types of Musculoskeletal Injuries on Blood Concentration of Serum Amyloid A in Thoroughbred Racehorses

BACKGROUND

Training-induced muscle, skeletal and joint trauma may result in acute phase response reflected by the changes in the blood concentration of serum amyloid A (SAA) in racehorses. It remains yet unclear if such systemic reaction could be triggered by sport injuries and what is the impact of different types of musculoskeletal trauma on SAA concentrations in racehorses. This study aimed to determine changes in the SAA blood concentration in racehorses with different types of injuries of musculoskeletal system.

MATERIALS AND METHODS

The study involved 28 racehorses diagnosed after the race with bone fractures (n = 7), dorsal metacarpal disease (n = 11), joint trauma (n = 4) or tendon and muscle trauma (n = 6) and 28 healthy control racehorses. Serum samples were collected twice, between 1 and 4 days of the injury or succesful completion of the race. SAA concentration was measured using the commercial ELISA kit. Differences between mean SAA concentration in respective groups were analyzed using ANOVA and Tukey post-hoc test.

RESULTS

Mean SAA concentration within the first 4 days of the injury of muscle and tendon was significantly higher than in bone fractures, dorsal metacarpal disease, joint trauma or in the healthy horses (p<0,001). There were no significant differences between the other groups.

CONCLUSIONS

Strain injuries of muscle and tendons can cause a moderate increase in SAA blood concentration in racehorses, reflecting the occurrence of the acute phase response. Similar reaction is not observed in the stress-related bone injuries.

Concentrations of serum amyloid A and plasma fibrinogen in horses undergoing emergency abdominal surgery

OBJECTIVE

To compare the perioperative response of serum amyloid A (SAA) to fibrinogen in horses requiring exploratory celiotomy for colic and to determine if SAA could be used to predict complications and outcome.

DESIGN

Prospective observational clinical study.

SETTING

University teaching hospital.

ANIMALS

Eighteen horses undergoing exploratory celiotomy for colic. Inclusion criteria for the study included survival and anesthetic recovery from exploratory celiotomy, no history of surgery within the past year.

INTERVENTIONS

Blood was obtained via jugular venipuncture before surgery (time 0) and at 24, 48, 72, and 96 hours after recovery from anesthesia.

MEASUREMENTS AND MAIN RESULTS

Quantitative and semiquantitative fibrinogen, SAA, total nucleated cell counts, and total protein were evaluated at each time point. Multivariable linear regression was used to assess differences at each time point and after grouping horses according to duration of colic prior to surgery, strangulating surgical lesion or not, presence of systemic inflammatory response syndrome (SIRS) on admission, and postsurgical complications. Significant (P < 0.05) increases in SAA concentrations occurred in all cases after surgery compared to fibrinogen concentration, which only demonstrated a mild, clinically insignificant increase postsurgery. SAA concentrations were also significantly increased (P < 0.05) in cases identified with SIRS prior to surgery and postoperatively at 48 (P = 0.05) and 72 hours (P = 0.02) in horses that developed complications.

CONCLUSIONS

Measurement of SAA is a more sensitive indicator of inflammation than fibrinogen in the perioperative period of horses requiring exploratory celiotomy for colic. Serial measurement of SAA at 48, 72, and 96 hours after surgery may be helpful to determine risk of complications and guide postoperative management. Measurement of SAA on admission also allows for quantification of SIRS when it is detected clinically.

Insights into the antimicrobial properties of hepcidins: advantages and drawbacks as potential therapeutic agents

The increasing frequency of multi-drug resistant microorganisms has driven research into alternative therapeutic strategies. In this respect, natural antimicrobial peptides (AMPs) hold much promise as candidates for the development of novel antibiotics. However, AMPs have some intrinsic drawbacks, such as partial degradation by host proteases or inhibition by host body fluid composition, potential toxicity, and high production costs. This review focuses on the hepcidins, which are peptides produced by the human liver with a known role in iron homeostasis, as well by numerous other organisms (including fish, reptiles, other mammals), and their potential as antibacterial and antifungal agents. Interestingly, the antimicrobial properties of human hepcidins are enhanced at acidic pH, rendering these peptides appealing for the design of new drugs targeting infections that occur in body areas with acidic physiological pH. This review not only considers current research on the direct killing activity of these peptides, but evaluates the potential application of these molecules as coating agents preventing biofilm formation and critically assesses technical obstacles preventing their therapeutic application.

Diagnostic and predictive capability of routine laboratory tests for the diagnosis and staging of equine inflammatory disease

Background

A wide spectrum of laboratory tests is available to aid diagnosis and classification of equine inflammatory disease.

Objectives

To compare diagnostic efficacy and combined predictive capability of the myeloperoxidase index (MPXI), and plasma fibrinogen, iron and serum amyloid A (SAA) concentrations for the diagnosis of inflammation.

Animals

Twenty‐six hospitalized horses with systemic inflammation (SI), 114 with local inflammation (LI) and 61 healthy horses or those with noninflammatory disease (NI) were included.

Methods

A retrospective study was performed; clinicopathologic data from horses were compared between groups. Receiver‐operator characteristic (ROC) curves were used to evaluate diagnostic efficacy; classification and regression tree analysis (CART) and logistic regression analysis were used to generate diagnostic algorithms.

Results

Horses with SI had significantly higher SAA than horses with LI (P = .007) and NI (P < .001) and lower iron concentrations than horses with LI (P < .001) and NI (P < .001). Fibrinogen concentration was higher in horses with inflammation than in those without inflammation (P = .002). There was no difference between the SI and LI groups. White blood cell count, neutrophil count and MPXI were similar between groups. SAA had the highest accuracy for diagnosing inflammation (area under ROC curve [AUC], 0.83 ± 0.06) and iron and SAA concentration had the highest accuracy for differentiating SI from LI (AUC, 0.80 ± 0.09 and 0.73 ± 0.10 respectively). Predictive modeling failed to generate useful algorithms and classification of cases was moderate.

Conclusions and Clinical Importance

Very high SAA and low iron concentrations may reflect SI, but diagnostic guidelines based on quantitative results of inflammatory markers could not be formulated.

The Equine PeptideAtlas: a resource for developing proteomics-based veterinary research

Progress in MS-based methods for veterinary research and diagnostics is lagging behind compared to the human research, and proteome data of domestic animals is still not well represented in open source data repositories. This is particularly true for the equine species. Here we present a first Equine PeptideAtlas encompassing high-resolution tandem MS analyses of 51 samples representing a selection of equine tissues and body fluids from healthy and diseased animals. The raw data were processed through the Trans-Proteomic Pipeline to yield high quality identification of proteins and peptides. The current release comprises 24 131 distinct peptides representing 2636 canonical proteins observed at false discovery rates of 0.2% at the peptide level and 1.4% at the protein level. Data from the Equine PeptideAtlas are available for experimental planning, validation of new datasets, and as a proteomic data mining resource. The advantages of the Equine PeptideAtlas are demonstrated by examples of mining the contents for information on potential and well-known equine acute phase proteins, which have extensive general interest in the veterinary clinic. The extracted information will support further analyses, and emphasizes the value of the Equine PeptideAtlas as a resource for the design of targeted quantitative proteomic studies.

Assessment of serum amyloid A testing of horses and its clinical application in a specialized equine practice

OBJECTIVE

To compare serum amyloid A (SAA) concentration, plasma fibrinogen concentration, total WBC count, and serum albumin-to-globulin concentration ratio (A:G ratio) in clinically normal (CN) and clinically abnormal (CA) horses.

DESIGN

Prospective cohort study.

ANIMALS

111 CN horses and 101 CA horses hospitalized at a specialty clinical practice.

PROCEDURES

Shortly after admission, a blood sample (20 mL) was collected from each horse for a CBC, serum protein electrophoresis, and determination of plasma fibrinogen concentration; SAA concentration was assessed with a previously validated immunoturbidometric assay. Similar testing of a subset of CA horses was conducted at various points during treatment.

RESULTS

Total WBC count, A:G ratio, and SAA concentration were determined for all 212 horses; data regarding plasma fibrinogen concentration were available for 127 horses (of which 47 were CN and 80 were CA). Median SAA concentration, total WBC count, and plasma fibrinogen concentration and mean A:G ratio differed significantly between CN horses and CA horses. Correlations between these variables were poor to weak. For discrimination of CN horses from CA horses, the SAA assay had sensitivity of 53% and specificity of 94% (diagnostic accuracy, 75%); for the other assessments, accuracy ranged from 59% to 62%. Repeated assessment of SAA concentration in some CA horses revealed a gradual return to normal concentrations.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that assessment of SAA concentration can provide valuable information regarding the clinical state of horses and may be more useful for patient monitoring and as a prognostic indicator than are traditional markers of inflammation.

Freund's adjuvant-induced inflammation: clinical findings and its effect on hepcidin mRNA expression in horses

Hypoferremia observed during systemic inflammatory disorders is regulated by hepcidin. Hepcidin up-regulation is particularly important during acute inflammation, as it restricts the availability of iron, which is necessary for pathogenic microorganism growth before adaptive immunity occurs. The aim of this study was to evaluate the clinical findings and hepatic hepcidin mRNA expression in horses using a Freund's complete adjuvant (FCA) model of inflammation. The expression of hepcidin mRNA in the liver was determined in healthy horses following two intramuscular injections of FCA at 0 h and 12 h. Plasma iron and fibrinogen concentrations were measured at multiple time points between 0 h and 240 h post-FCA injection (PI). Hepcidin mRNA expression was determined by RT-qPCR using liver biopsy samples performed at 0 h (control), 6 h and 18 h PI. The mean plasma fibrinogen level was significantly different from the control values only between 120 and 216 h PI. The mean plasma iron level was significantly lower than the control between 16 and 72 h PI, reaching the lowest levels at 30 h PI (33 % of the initial value), and returned to the reference value from 96 h PI to the end of the experiment. Hepcidin mRNA expression increased at 6 h PI and remained high at 18 h PI. The iron plasma concentration was an earlier indicator of inflammatory processes in horses when compared with fibrinogen and might be useful for the early detection of inflammation in the horse. FCA administration caused the rapid onset of hypoferremia, and this effect was likely the result of up-regulated hepatic hepcidin gene expression. This study emphasizes the importance of hepcidin and iron metabolism during inflammation in horses.

Serum iron as an indicator of acute inflammation in cattle

The aim of this study was to assess the value of serum iron concentration in the diagnosis of acute inflammation in cattle. The diagnostic value of this approach was compared with that of various other hematological tests, including commonly used techniques that measure the levels of various other acute-phase proteins. The study population comprised 10 cows with acute traumatic reticuloperitonitis (RPT group) and 10 cows with acute mastitis (mastitis group) admitted to the Veterinary Teaching Hospital at Firat University (Elaziğ, Turkey). Ten cows from local barns, kept and fed under same conditions as the diseased animals, were used as controls. After the clinical examination, blood samples were collected for biochemical, hematological, and acute-phase protein (haptoglobin, serum amyloid A, α-1 acid glycoprotein, and fibrinogen) analyses. The mean levels of serum iron in the RPT, mastitis, and control groups were 6.00, 7.82, and 26.78 µmol/L, respectively. Serum iron level was significantly reduced in the RPT and mastitis groups. The results of this study indicate that serum iron analysis, preferably in combination with other markers of inflammation, may be a useful diagnostic tool for acute inflammation in cattle. Because serum iron measurement is individually available and easily applicable, it may be used for clinical cases as well as the determination of herd health.