Effects of surgery on the acute phase response in clinically normal and diseased horses

Abstract

The serum concentrations of serum amyloid A, haptoglobin and fibrinogen were measured in a group of horses before and at intervals after elective and non-elective surgery, and in a control group of normal horses. There was a significant, rapid and repeatable increase in the concentration of serum amyloid A in response to both elective and non-elective surgery. In the control horses its serum concentration was within the normal range, from 0 to 0.2 microg/ml. Twenty-four hours after elective surgery its mean peak concentration was 16.4 microg/ml, and after non-elective surgery it was 27.3 microg/ml. In contrast, the serum concentrations of haptoglobin and fibrinogen increased more slowly after surgery and had not decreased by 72 hours after surgery.

Factors Influencing Serum Amyloid Type A (Saa) Concentrations in Horses

“…This evolution experienced by the SAA with age confirmed previous results from research in human [41]. The higher incidence of diseases of diverse origin with advancing age seems to be the source of the increase of this protein in older animals, although not all researchers agree with this theory [33].…”

“…Colostral levels of this protein are closely related to serum levels in healthy foals at 48 hours after birth, suggesting that the protein can be absorbed intact through the intestine and alter the circulating levels. By contrast, other researchers have shown undetectable levels of this protein in healthy foals during this same time period [24,33,40]. These controversial results suggest that fluctuations in the levels of age-dependent SAA are so insignificant that no clinical significance in the horse.…”

“…Generically, surgery induces a marked APR, characterized by a biphasic pattern of SAA [23,31,33]. In particular, after castration, SAA levels have been identified above 7 mg/L, with a peak at 2 -3 days followed by a second rise 4 or 5 days after surgery [23].…”

“…Finally, the standard method of measurement of Fb is insensitive to small changes, so it only detects changes above 100 mg/dL [33]. Furthermore, the levels of SAA rise when the inflammatory process is active, and fall after the cessation of the stimulus.…”

Acute Phase Proteins in Racehorses with Inflammatory Airway Disease

“…Serum amyloid A was quantified using an assay1 previously validated in horses 10. C‐reactive protein and haptoglobin were quantified using CRP and haptoglobin ELISAs for equine biological samples 2, 3.…”