Effects of Long-Term Storage Time and Original Sampling Month on Biobank Plasma Protein Concentrations.
Author(s): Enroth S, Hallmans G, Grankvist K, Gyllensten U
Publication: EBioMedicine, 2016, Vol. 12, Page 309-314
PubMed ID: 27596149 PubMed Review Paper? No
Purpose of Paper
This paper investigated the effects of storage duration, patient age, season, and number of sunlight hours per day on levels of 108 proteins in plasma.
Conclusion of Paper
Although variations with patient age were observed in levels of 45 of the 108 proteins examined after results were corrected for storage duration and multiple testing, only the differences in cancer antigen-125 (CA-125) levels were found to be statistically significant. Season and number of sunlight hours per day had no significant effects on protein levels after results were adjusted for storage duration and patient age.
Studies
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Study Purpose
This study investigated the effects of storage duration, patient age, season, and number of sunlight hours on levels of 108 proteins in plasma. A total of 380 plasma specimens were obtained from the blood of 106 female patients in the Västerbotten intervention program (208 specimens) and Mammography Screening Project (172 specimens). All blood was collected into EDTA tubes and processed within 1 h. The resultant plasma was stored at -80˚C until analysis. Levels of 132 proteins were quantified by Proximity Extension Assay (PEA) but 14 proteins were removed from the analysis due to being below the limit of detection in >80% of specimens. The effects of storage duration were investigated using 92 blood specimens from patients who were 50 ± 0.5 years, but the effects of patient age, season, and number of hours of sunlight per day were investigated using all 380 specimens.
Summary of Findings:
Storage duration significantly affected levels of 18 of the 108 proteins analyzed (P<0.05) and accounted for 4.9-34.9% of the variations observed; however, only the 17% increase in CA-125 was found to be significant (P<4.6 x 10-4) after results were correction for multiple testing. Patient age had a significant effect on the storage duration-adjusted levels of 70 proteins (P<0.05), including 16 of those affected by storage duration, and accounted for 1.1-33.5% of the variation observed. Of these 70 proteins, 45 were still significant after correction for multiple testing (P<4.6 x 10-4). The effect of patient age on levels of interleukin-27a (IL-27a) and the c-kit ligand, SCF, was verified by analysis of multiple specimens from the same patients taken over time. Seasonal differences were found in levels of 15 proteins after adjusting for patient age and storage duration (P<0.05), but none of the differences were considered significant after correcting for multiple testing. Similarly, the number of sun hours a day was significantly correlated with levels of 36 proteins, but the effect was small (<4.5% of the variation) and was not significant after correction for multiple testing.
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Protein Immuno-PCR Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Preaquisition Patient age 30 years
40 years
50 years
60 years
70 years
42-73 years
Storage Storage duration 2-27 years
Biospecimen Acquisition Time of biospecimen collection Winter
Spring
Summer
Fall
Varying numbers of sunlight hours