Measurement of Calprotectin (S100A8/A9) in the Saliva of Pigs: Validation Data of A Commercially Available Automated Assay and Changes in Sepsis, Inflammation, and Stress

Abstract

Calprotectin (CALP, S100A8/A9), also named myeloid-related protein 8/14, is a dimer complex of S100A8 and S100A9 that belongs to the S-100 protein family. It is involved in inflammation and has a wide range of proinflammatory functions, such as cytokine production and regulation of leukocyte adhesion, migration, and phagocytosis. In humans, CALP traditionally can be measured in faeces, serum, and saliva as a biomarker of inflammation and sepsis. The objective of this study was to validate an automated assay for CALP measurements in the saliva of pigs, having the advantage of the use of a non-invasive sample that is easy to collect. The assay was precise and accurate. CALP in saliva measured by this assay showed significant changes depending on the hour of the day. It also showed significant increases in the saliva of pigs after the administration of lipopolysaccharide (LPS), and showed a rise, although with increases of lower magnitude, after a stressful stimulus. Further studies should be made to gain knowledge about the possible practical applications of the measurements of CALP in the saliva of pigs as a biomarker to evaluate the animals’ health and welfare.

Changes in S100A8/A9 and S100A12 and Their Comparison with Other Analytes in the Saliva of Pigs with Diarrhea Due to E. coli

“…Based on this, it would be recommended that, in any case, each different assay should be validated from an analytical point of view in the species and sample type to be used before its application. In the case of assays for the measurement of S100A8/A9 and S100A12 used in the present study, saliva samples with a known concentration of each analyte were used as calibrators to take the advantage of reducing the matrix effect [ 14 ].…”

“…S100A8/A9 was analyzed with the BÜHLMANN fCal Turbo ® assay kit (BÜHLMANN, Laboratories AG, Schönenbuch, Switzerland) using an Olympus AU400 autoanalyzer. This assay is designed for humans, but it has been demonstrated to have cross-reactivity with calprotectin in pigs [ 22 ] and has been validated for use in the saliva of this species [ 14 ]. The description of this assay and the other automated assays used in this study appears in Supplementary Table S1 .…”

“…Saliva can be collected easily by farm staff, allowing for more frequent analysis and monitoring and subsequently better control of the health and welfare of the animals. In research, the saliva of pigs has shown utility in the detection of infectious pathogens being currently used in routine practice for this purpose [ 12 ], but it can also be used to measure biomarkers that provide insight into stress, inflammation, immune response, and redox homeostasis [ 12 , 13 , 14 , 15 , 16 ]. Therefore, saliva is a rich source of analytes that have the potential to be biomarkers of different physiopathological conditions and diseases, assess the effects of various husbandry conditions and, in general, evaluate the homeostasis of swine and provide information about its health and welfare.…”

“…However, the use of saliva also has challenges such as the need, in some cases, for high-sensitivity assays for the detection of some analytes that are in low concentration in this fluid. Recently, it has been described that calprotectin can be measured in the saliva of pigs showing increases in experimentally induced sepsis [ 14 ], as well as the increases in calprotectin and S100A12 in saliva in pigs with meningitis due to Streptococcus suis [ 17 ]. In addition, S100A12 has been measured in human saliva in inflammatory bowel disease [ 18 ].…”

“…The following supporting information can be downloaded at: . References [ 14 , 15 , 25 , 26 , 27 , 30 , 53 , 54 ] are cited in the supplementary materials.…”