Email updates

Keep up to date with the latest news and content from Proteome Science and BioMed Central.

Open Access Research

Pre-analytical stability of the plasma proteomes based on the storage temperature

Sara Pasella1, Angela Baralla1, Elisabetta Canu1, Sara Pinna1, James Vaupel2, Marta Deiana3, Claudio Franceschi4, Giovannella Baggio5, Angelo Zinellu1, Salvatore Sotgia1, Giuseppe Castaldo6, Ciriaco Carru1 and Luca Deiana178*

Author Affiliations

1 Biochimica Clinica e Biologia Molecolare Clinica, Dipartimento di Scienze Biomediche, Università di Sassari, Sassari, Italy

2 Max Planck Institute for Demographic Research, Rostock, Germany

3 Associazione “Isola dei Centenari”, Sassari, Italy

4 Dipartimento di Patologia Sperimentale, Università di Bologna, Bologna, Italy

5 Azienda Ospedaliera di Padova, Padua, Italy

6 Dipartimento di Biochimica e Biotecnologie Mediche, Universita’ di Napoli Federico II, Naples, Italy

7 Azienda Ospedaliera Universitaria di Sassari, Sassari, Italy

8 Center for Biotechnology Development and Biodiversity Research, University of Sassari, Sassari, Italy

For all author emails, please log on.

Proteome Science 2013, 11:10  doi:10.1186/1477-5956-11-10

Published: 21 March 2013

Abstract

Background

This study examined the effect of storage temperature on the protein profile of human plasma. Plasma samples were stored for 13 days at -80°C, -20°C, +4°C and room temperature (20-25°C) prior to proteomic analysis. The proteomic comparisons were based on the differences of mean intensity values of protein spots between fresh plasma samples (named “time zero”) and plasma samples stored at different temperatures. To better understand the thermally induced biochemical changes that may affect plasma proteins during storage we identified proteins with different expressions with respect to the time zero sample.

Results

Using two-dimensional electrophoresis followed by MALDI-TOF MS and /or LC-MS/MS 20 protein spots representing 10 proteins were identified with significant differences in abundance when stored at different temperatures. Our results, in agreement with various authors, indicate that during storage for a short period (13 days) at four different temperatures plasma proteins were more affected by degradation processes at +4°C compared to the other temperatures analysed. However, we founded that numerous protein spots (vitamin D binding protein, alpha-1-antitrypsin, serotransferrin, apoplipoprotein A-I, apolipoprotein E, haptoglobin and complement factor B) decrease in abundance with increasing temperature up to 4°C, but at room temperature their intensity mean values are similar to those of time zero and -80°C. We hypothesize that these proteins are labile at 4°C, but at the same time they are stable at room temperature (20-25°C). Furthermore we have grouped the proteins based on their different sensitivity to the storage temperature. Spots of serum albumin, fibrinogen gamma chain and haptoglobin are more resistant to the higher temperatures tested, as they have undergone changes in abundance only at room temperature; conversely, other spots of serum albumin, fibrinogen beta chain and serotransferrin are more labile as they have undergone changes in abundance at all temperatures except at -80°C.

Conclusions

Although there are many studies concerning protein stability of clinical samples during storage these findings may help to provide a better understanding of the changes of proteins induced by storage temperature.

Keywords:
Two-dimensional electrophoresis; Mass spectrometry; Plasma proteome; Specimen collection and handling; Storage temperature