Abstract
Background
Insulin-like growth factors I (IGF-I and -II) and their binding proteins (IGFBPs) are important for growth and metabolism. In dogs measurements of IGFs may be used in diagnosing growth-related disorders and non-islet cell tumor hypoglycemia (NICTH) caused by tumor production of immature IGF-II (big-IGF-II). In humans IGFBP-3 is used for diagnosing growth-related diseases. Little is known about the clinical usefulness of IGFBP-3 and IGF-II in dogs. Analysis of IGFs with immunoassays are complicated by interference of IGF-binding proteins.
Furthermore species-specific antibodies are often non available. Mass spectrometry (MS)-based methods offers many advantages: the interference of other proteins during analysis is reduced, multiple proteins can be measured in the same run and the methods can be
developed for any species.
Objective
To develop a targeted MS-based method for quantification of canine total IGF-I, –II and IGFBP-3.
Methods
A targeted MS-based quantification method for the mature proteins, applying parallel reaction monitoring, was developed. Serum from one dog with suspected NICTH before and after removal of the tumor was used for evaluation.
Results
The method was successfully developed. Tryptic peptides and corresponding isotopically labelled standards were identified and selected. Duplicate CV varied from 0.1-35% with IGFBP-3 yielding the highest CV. As expected, removal of the tumor resulted in an increase in IGF-I and IGFBP-3, likely due to reduced negative feedback on GH production. There was a slight decrease in total IGF-II after removal of the tumor.
Conclusions
We have developed a method for quantification of total IGF-I, -II and IGFBP-3 in dogs. Further studies are needed to establish reference intervals and evaluate the clinical usefulness with this method. Future work will target the immature form of IGF-II as a diagnostic tool in canine NICTH.
Insulin-like growth factors I (IGF-I and -II) and their binding proteins (IGFBPs) are important for growth and metabolism. In dogs measurements of IGFs may be used in diagnosing growth-related disorders and non-islet cell tumor hypoglycemia (NICTH) caused by tumor production of immature IGF-II (big-IGF-II). In humans IGFBP-3 is used for diagnosing growth-related diseases. Little is known about the clinical usefulness of IGFBP-3 and IGF-II in dogs. Analysis of IGFs with immunoassays are complicated by interference of IGF-binding proteins.
Furthermore species-specific antibodies are often non available. Mass spectrometry (MS)-based methods offers many advantages: the interference of other proteins during analysis is reduced, multiple proteins can be measured in the same run and the methods can be
developed for any species.
Objective
To develop a targeted MS-based method for quantification of canine total IGF-I, –II and IGFBP-3.
Methods
A targeted MS-based quantification method for the mature proteins, applying parallel reaction monitoring, was developed. Serum from one dog with suspected NICTH before and after removal of the tumor was used for evaluation.
Results
The method was successfully developed. Tryptic peptides and corresponding isotopically labelled standards were identified and selected. Duplicate CV varied from 0.1-35% with IGFBP-3 yielding the highest CV. As expected, removal of the tumor resulted in an increase in IGF-I and IGFBP-3, likely due to reduced negative feedback on GH production. There was a slight decrease in total IGF-II after removal of the tumor.
Conclusions
We have developed a method for quantification of total IGF-I, -II and IGFBP-3 in dogs. Further studies are needed to establish reference intervals and evaluate the clinical usefulness with this method. Future work will target the immature form of IGF-II as a diagnostic tool in canine NICTH.
| Original language | English |
|---|---|
| Pages | 158-158 |
| Number of pages | 1 |
| Publication status | Published - 20 Oct 2016 |
| Event | European Congress of Veterinary Clinical Pathology - Nantes, France Duration: 20 Oct 2016 → 22 Oct 2016 https://www.esvcp.org/index.php/latest-news/262-congress-nantes-program.html |
Conference
| Conference | European Congress of Veterinary Clinical Pathology |
|---|---|
| Abbreviated title | 2016 ESVCP-ESVONC |
| Country/Territory | France |
| City | Nantes |
| Period | 20/10/16 → 22/10/16 |
| Internet address |