Investigation of the solubility and the potentials for purification of serum amyloid A (SAA) from equine acute phase serum – a pilot study

Christensen, Michelle B.; Sørensen, Jens Christian; Jacobsen, Stine; Kjelgaard‐Hansen, Mads

doi:10.1186/1756-0500-6-152

Cited by 5 publications

(5 citation statements)

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“…Due to the heterologous calibration of the assay, the true concentration of equine SAA is unknown. No standard preparations of purified equine SAA are available, possibly due to the well-known difficulties in purifying SAA [19]. Consequently, in the VET-SAA, LZSAA and other SAA assays used in equine medicine, calibration curves are based on recombinant human SAA, and concentrations are thus expressed as human equivalents.…”

Section: Discussionmentioning

confidence: 99%

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

Jacobsen

Vinther

Kjelgaard‐Hansen

et al. 2019

Preprint

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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.

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Section: Discussionmentioning

confidence: 99%

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

Jacobsen

Vinther

Kjelgaard‐Hansen

et al. 2019

Preprint

Self Cite

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show abstract

“…Due to the heterologous calibration of the assay, the true concentration of equine SAA is unknown. No standard preparations of purified equine SAA are available, possibly due to the well-known difficulties in purifying SAA [17]. Consequently, in the VET-SAA, LZ SAA and other SAA assays used in equine medicine, calibration curves are based on recombinant human SAA, and concentrations are thus expressed as human equivalents.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2019

Self Cite

View full text Add to dashboard Cite

BackgroundSerum 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.ResultsDetection 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.ConclusionsThe 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.

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“…Finally, before SAA can be used as a dilution marker, there needs to be clarification over how it enters saliva and whether salivary SAA reflects serum levels. SAA is a lipophilic molecule of between 11.4 and 12.5 kDa, therefore it may enter the oral cavity via active transport and transudation, which is different from CRP (60,81,82). Moreover, SAA may be produced locally as mRNA has been detected within human tonsillar tissue (83).…”

Section: Development Of a Dilution Markermentioning

confidence: 99%

Towards salivary C-reactive protein as a viable biomarker of systemic inflammation

Pay

Shaw

2019

Clinical Biochemistry

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C-reactive protein (CRP) is a commonly used marker of systemic inflammation, routinely measured in serum blood samples. However salivary samples offer a noninvasive and easily accessible alternative which would improve point of care (POC) testing for inflammation. Two major challenges restrict the use of saliva: the influence of the oral environment on CRP and its local production; and collecting a standardised sample given patient-dependent salivary flow rates. Here we review the reported studies of salivary CRP in humans as a potential marker of systemic inflammation and how the challenges can be overcome. Salivary CRP currently poorly reflects systemic inflammation as it does not consistently and strongly correlate with serum CRP. The mean and one standard deviation reported R 2 values are 0.53  0.23 from 14 studies. An improved understanding of the key challenges and implemented solutions are needed to optimise salivary CRP use. Firstly, control for the effects of local oral inflammation. Screening for oral trauma is one option, however this could drastically limit the number of patients suitable for salivary CRP testing and the number of professionals able to use the POC test. Secondly, the role of a dilution biomarker is considered controlling for salivary flow rate which dilutes serum CRP by ~10 4 ; a variable and likely-patient specific factor. The ideal dilution biomarker should have many of the pharmacokinetic, sensitivity and specificity characteristics of CRP. The potential for positive acute phase protein serum amyloid A (SAA) and negative acute phase protein albumin is considered and the characteristics of any correction function discussed. Currently, however, there are no available strategies to make salivary CRP a reliable quantitative measure of serum CRP and hence POC systemic inflammation testing.

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Investigation of the solubility and the potentials for purification of serum amyloid A (SAA) from equine acute phase serum – a pilot study

Cited by 5 publications

References 35 publications

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

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

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

Towards salivary C-reactive protein as a viable biomarker of systemic inflammation

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