Paraoxonase‐1 activity evaluation as a diagnostic and prognostic marker in horses and foals

Abstract

Background In several species, paraoxonase‐1 (PON‐1) decreases during inflammation, because of the presence of oxidative stress; its measurement recently has been validated in horses, but its role as a clinical biomarker is unknown. Objectives To evaluate sensitivity, specificity and likelihood ratio of PON‐1 activity to identify systemic inflammatory response syndrome (SIRS)‐positive horses or horses with a poor prognosis. Animals One hundred seventy‐two blood samples from 58 sick horses from 3 different veterinary hospitals. Methods In a cross‐sectional study, PON‐1 activity was measured upon admission and at 24‐hour intervals until discharge or death, and results were analyzed based on SIRS status and outcome. Results No statistically significant difference was found in median PON‐1 activity between SIRS and non‐SIRS cases or between survivors and non‐survivors except for mares, in which PON‐1 activity was significantly lower in SIRS‐positive horses (P = .05). The sensitivity of PON‐1 activity in identifying horses with SIRS or negative outcome was low (0.0%‐46.2% depending on the examined group) but its specificity was high (87.0%‐100.0%). However, when PON‐1 is low, the likelihood of death is 2.40‐3.89 times higher than the likelihood of survival. Repeated measurement of PON‐1 after treatment does not predict outcome. Conclusions and Clinical Importance Evaluation of PON‐1 activity in horses with inflammation might be advisable in the future, but only low activity at admission may be relevant in predicting SIRS or negative outcome.

Serial measurements of Paraoxonase-1 (PON-1) activity in horses with experimentally induced endotoxemia

“…Again, this delayed response may explain the lack of correlations between PON-1 activity and many laboratory changes, except for fibrinogen that, being a positive acute phase protein, negatively correlated, as expected, with PON-1 activity and for the PCV that increased soon after LPS infusion likely due to dehydration and then decreased to normal values, thus paralleling the late decrease of PON-1. This late PON-1 response could be interpreted as a delayed occurrence of inflammatory oxidations and oxidative stress, possibly due to a different PON-1 metabolism during inflammation in horses compared to other species, as suggested by Ruggerone et al [ 15 ]. Otherwise, it may also be possible that anti-inflammatory oxidations occurred in the first 12 h post-LPS infusion, determining PON-1 activity fluctuations not wide enough to produce significant changes, possibly because of a less severe oxidative stress in horses compared to other species (Ruggerone et al, 2020).…”

“…A recent study validated a paraoxon-based method to measure serum PON-1 activity in horses and provided reference intervals in healthy animals for this species [ 28 ]. Interestingly, in a further study, low PON-1 activity was reported only in some of the horses with systemic inflammatory response syndrome (SIRS) [ 15 ]. Therefore, although the latter study indicated that low PON-1 activity at admission may predict the presence of SIRS or a poor outcome, to date very little is known about PON-1 in horses, and additional information is required to confirm that this protein could have a diagnostic or prognostic marker, as reported for other species.…”

Role of paraoxonase-1 as a diagnostic marker for feline infectious peritonitis

“…A previous study had highlighted how PON-1 activity decreases in cats affected by infectious diseases including FIP (Tecles et al, 2015). This may likely occur due to its dual role as negative acute phase reactant and antioxidant compound, as demonstrated in other species (Rossi et al, 2014;Ruggerone et al, 2020). Indeed, PON-1 tends to decrease significantly in those inflammatory processes that involve a strong oxidative stress.…”

Serial measurements of Paraoxonase-1 (PON-1) activity in horses with experimentally induced endotoxemia

“…In the last year's research, there has been growing interest about the role of PON-1 in the pathogenesis of many diseases characterized by oxidative stress, primarily in human medicine (11,12), but more recently also in veterinary medicine. In particular, several studies have highlighted the potential of PON-1 in the pathogenesis, diagnosis and prediction of outcome in naturally occurring and experimentally induced sepsis in many species, including horses (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). During the acute phase response, changes in lipoprotein occur (26) and PON-1 in HDL is replaced by acute phase proteins, mainly serum amyloid A.…”

“…A recent study validated a paraoxon-based method to measure serum PON-1 activity in horses and provided reference intervals in healthy animals for this species (28). Interestingly, in a further study, low PON-1 activity was reported only in some of the horses with systemic in ammatory response syndrome (SIRS) (15). Therefore, although the latter study indicated that low PON-1 activity at admission may predict the presence of SIRS or a poor outcome, to date very little is known about PON-1 in horses, and additional information is required to con rm that this protein could have a diagnostic or prognostic marker, as reported for other species.…”