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Serum Paraoxonase-1 (PON-1) in Dogs: Frequency of Decreased Values in Clinical Practice and Prognostic Significance
by
, , , , and
Virginia Bettoni
,
Filippo Tagliasacchi
*,
Donatella Scavone
,
Alberto Galizzi
,
Chiara Locatelli
,
Maria Amati
,
Roberta Ferrari
,
Paola Scarpa
and
Saverio Paltrinieri
Department of Veterinary Medicine and Animal Sciences, University of Milan, 26900 Lodi, Italy
*
Author to whom correspondence should be addressed.
Vet. Sci. 2025, 12(11), 1066; https://doi.org/10.3390/vetsci12111066
Submission received: 13 October 2025
/
Revised: 29 October 2025
/
Accepted: 1 November 2025
/
Published: 6 November 2025
Simple Summary
Paraoxonase-1 is a serum enzyme with antioxidant and anti-inflammatory properties, synthesized in the liver and associated with high-density lipoproteins. Its activity tends to decrease during systemic inflammation or oxidative stress, making it useful as a potential biomarker for disease severity and prognosis. This study analyzed the serum activity of paraoxonase-1 in 482 samples, evaluating its role in different hospital departments and its possible prognostic value. Results showed that the emergency/first-aid unit had the highest frequency of low PON-1 values and the lowest median. There were no significant differences between survivors and non-survivors in terms of mean PON-1 activity, but a reduction was observed during hospitalization in non-survivors. In conclusion, measurement of PON-1 is recommended in clinical practice, especially at admission to the emergency department, because very low values may indicate the need for hospitalization, and a further decline during hospitalization could indicate a poor prognosis.
Abstract
Serum activity of paraoxonase-1 (PON-1) decreases in canine inflammation. This study aimed to evaluate how frequently PON-1 activity is reduced across different disease categories and to assess its potential prognostic significance. PON-1 activity was measured in 482 samples (435 first visit, 47 follow-up) collected during routine clinical activities. The emergency/first-opinion unit (EF) had the highest frequency of low values (18.3%) and lower median PON-1 activity (170.3 U/mL) compared with other units. The proportion of lower values and median PON-1 values were, respectively, significantly higher and lower in acute/severe diseases compared with chronic/mild diseases (13.3 vs. 7.1%; 177.0 vs. 192.9 U/mL) and in hospitalized compared with non-hospitalized dogs (27.7 vs. 4.5%; 150.0 vs. 193.0 U/mL). Low PON-1 activity may predict the need for hospitalization: values < 45.7 U/mL have a likelihood ratio of 14.4. The proportion of lower values and the median Paraoxonase-1 activity did not differ between survivors and non-survivors (18.2 vs. 25.0%; 162.0 vs. 161.3 U/mL). However, PON-1 activity diminished during hospitalization only in non-survivors. PON-1 activity should be measured in routine practice, especially in the EF; hospitalization may be warranted when results are markedly low. Decreases in PON-1 activity during hospitalization may suggest a negative outcome.
