Serum biobank certification and the establishment of quality controls for biological fluids: examples of serum biomarker stability after temperature variation

Impact of cryopreservation on serum concentration of matrix metalloproteinases (MMP)-7, TIMP-1, vascular growth factors (VEGF) and VEGF-R2 in Biobank samples

BACKGROUND

Blood biomarkers are subject to pre-analytical variability. In many cases, the stability of important new tissue biomarkers during freeze cycles and storage has not been studied sufficiently.

METHODS

To test the stability of matrix metalloproteinases-7 (MMP-7) and their tissue inhibitors (TIMP-1), vascular growth factors (VEGF) and VEGF-receptor, serum samples were frozen and then thawed up to six times. The impact of storage temperature was investigated using an accelerated stability testing protocol. Stability at -20°C and -75°C was calculated using the Arrhenius equation.

RESULTS

The average concentration of TIMP-1 was stable, even after six freeze/thaw cycles. One thawing did not change the concentration of MMP-7 and VEGF-receptor. However, repeated freeze/thaw cycles increased the measured values significantly. Decreases in VEGF concentrations were dramatic, even after the first freeze/thaw cycle. According to the Arrhenius calculation, MMP-7 showed excellent stability, at least 5 years at -20°C and several 100 years at -75°C. The VEGF-receptor maintains 90% of its initial concentration at -20°C over 3 months, and decades at -75°C. TIMP-1 and VEGF showed poor stability with cryopreservation, even at -75°C.

CONCLUSIONS

The stability of MMP-7, TIMP-1, VEGF or VEGF-receptor in biobanking is highly variable, and this should be taken into account in the interpretation of results. A temperature -20°C is unsuitable for prolonged storage of the biomarkers investigated, and repeated thawing of sera is not recommended. VEGF is especially unstable and should be quantitated using serum that has never been frozen.

New concepts of biobanks--strategic chance for uro-oncology

Cancer, as well as other common diseases, is a complex condition that not only causes a major threat to human health, but also represents a huge burden to society in terms of healthcare cost and loss of economic productivity. Treatment improvements remain elusive, since the causes of cancer are due to a huge number of small and possibly additive effects arising from genetic susceptibility, lifestyle, and environmental conditions. Thus, progress in translational cancer research investigating these changes and their complex interaction is highly dependent on large series of cases (affected and unaffected individuals) including high quality samples and their associated data. Therefore, large and well-organized biobanks have been established, are underway, or are planned in many countries and institutions. The integration of these resources with powerful molecular and "omics" approaches, integrated bioinformatic tools hold the promise to further advance our knowledge of disease development, thus leading to better prevention and treatment strategies. However, these valuable and irreplaceable collections typically suffer from underutilization, due to fragmentation of the collections and their accessibility, lack of common management strategies, including consensus on standard operating procedures, unique policies of utilization, and distribution as well as missing input on a broad basis reflecting research needs on an interdisciplinary, multi-institutional fashion beyond project-driven interest. The uro-oncologic community has not yet contributed to these efforts to its full potential, and broad knowledge on the contemporary developments in the field of biobanking and input into these efforts are still missing. This review presents an overview on biobanking and may serve as an update to be integrated into future discussions on managing biobanks involving uro-oncology. It is based on the discussions at the last meeting of the International Bladder Cancer Network in Barcelona (Spain) in fall 2008 and has been also largely influenced by the works and discussions of the Marble Arch International Working Group on Biobanking for Biomedical Research.

The effect of preanalytical factors on stability of the proteome and selected metabolites in cerebrospinal fluid (CSF)

To standardize the use of cerebrospinal fluid (CSF) for biomarker research, a set of stability studies have been performed on porcine samples to investigate the influence of common sample handling procedures on proteins, peptides, metabolites and free amino acids. This study focuses at the effect on proteins and peptides, analyzed by applying label-free quantitation using microfluidics nanoscale liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (chipLC-MS) as well as matrix-assisted laser desorption ionization Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FT-ICR-MS) and Orbitrap LC-MS/MS to trypsin-digested CSF samples. The factors assessed were a 30 or 120 min time delay at room temperature before storage at -80 degrees C after the collection of CSF in order to mimic potential delays in the clinic (delayed storage), storage at 4 degrees C after trypsin digestion to mimic the time that samples remain in the cooled autosampler of the analyzer, and repeated freeze-thaw cycles to mimic storage and handling procedures in the laboratory. The delayed storage factor was also analyzed by gas chromatography mass spectrometry (GC-MS) and liquid chromatography mass spectrometry (LC-MS) for changes of metabolites and free amino acids, respectively. Our results show that repeated freeze/thawing introduced changes in transthyretin peptide levels. The trypsin digested samples left at 4 degrees C in the autosampler showed a time-dependent decrease of peak areas for peptides from prostaglandin D-synthase and serotransferrin. Delayed storage of CSF led to changes in prostaglandin D-synthase derived peptides as well as to increased levels of certain amino acids and metabolites. The changes of metabolites, amino acids and proteins in the delayed storage study appear to be related to remaining white blood cells. Our recommendations are to centrifuge CSF samples immediately after collection to remove white blood cells, aliquot, and then snap-freeze the supernatant in liquid nitrogen for storage at -80 degrees C. Preferably samples should not be left in the autosampler for more than 24 h and freeze/thaw cycles should be avoided if at all possible.

Immunological fingerprinting method for differentiation of serum samples in research-oriented biobanks

An immunoenzymatic serum fingerprinting method was developed to establish a serum sample fingerprint based on IgG titers obtained with three different antigens. Three widely expressed antigens were selected for their capacity to induce long-lasting humoral immune responses. This fingerprinting method may be used to differentiate between two serum samples and to determine whether they come from the same primary blood specimen. The method showed a specificity of 99.5%. This method is suitable as a quality control method for biobanked serum samples.

A consensus protocol for the standardization of cerebrospinal fluid collection and biobanking

There is a long history of research into body fluid biomarkers in neurodegenerative and neuroinflammatory diseases. However, only a few biomarkers in CSF are being used in clinical practice. One of the most critical factors in CSF biomarker research is the inadequate powering of studies because of the lack of sufficient samples that can be obtained in single-center studies. Therefore, collaboration between investigators is needed to establish large biobanks of well-defined samples. Standardized protocols for biobanking are a prerequisite to ensure that the statistical power gained by increasing the numbers of CSF samples is not compromised by preanalytical factors. Here, a consensus report on recommendations for CSF collection and biobanking is presented, formed by the BioMS-eu network for CSF biomarker research in multiple sclerosis. We focus on CSF collection procedures, preanalytical factors, and high-quality clinical and paraclinical information. The biobanking protocols are applicable for CSF biobanks for research targeting any neurologic disease.

Soluble CD40 ligand as a biomarker for storage-related preanalytic variations of human serum

There are currently no appropriate and sensitive biomarkers available to assess preanalytic variations in human biological fluids stored in biobanks. We identified soluble CD40 ligand (sCD40L) as the first ubiquitous biomarker to show an on-off response in serum exposed to moderate or elevated room temperature conditions. We used immunoenzyme assays to monitor the sCD40L response after 12 h storage at 37 degrees C or 48 h at 20 degrees C. Our findings show that prolonged storage of serum samples at elevated room temperature can be determined by the absence of detectable sCD40L.

Biobanking for better healthcare

Translational cancer research is highly dependent of large series of cases including high quality samples and their associated data. Comprehensive Cancer Centers should be involved in networks to enable large-scale multi-center research projects between the centers [Ringborg, U., de Valeriola, D., van Harten, W., Llombart-Bosch, A., Lombardo, C., Nilsson, K., Philip, T., Pierotti, M.A., Riegman, P., Saghatchian, M., Storme, G., Tursz, T., Verellen, D, 2008. Improvement of European translational cancer research. Collaboration between comprehensive cancer centers. Tumori 94, 143-146.]. Combating cancer knows many frontiers. Research is needed for prevention as well as better care for those who have acquired the disease. This implies that human samples for cancer research need to be sourced from distinct forms of biobanking. An easier access to these samples for the scientific community is considered as the main bottleneck for research for health, and biobanks are the most adequate site to try to resolve this issue [Ozols, R.F., Herbst, R.S., Colson, Y.L., Gralow, J., Bonner, J., Curran Jr., W.J., Eisenberg, B.L., Ganz, P.A., Kramer, B.S., Kris, M.G., Markman, M., Mayer, R.J., Raghavan, D., Reaman, G.H., Sawaya, R., Schilsky, R.L., Schuchter, L.M., Sweetenham, J.W., Vahdat, L.T., Winn, R.J., and the American Society of Clinical Oncology, 2007. Clinical cancer advances 2006: major research advances in cancer treatment, prevention, and screening: a report from the American Society of Clinical Oncology. J. Clin. Oncol. 25, 146-162.]. However, biobanks should not be considered a static activity. On the contrary, biobanking is a young discipline [Morente, M.M., Fernandez, P.L., de Alava, E. Biobanking: old activity or young discipline? Semin. Diagn. Pathol., in press.], which need continuously evolve according to the permanent development of new techniques and new scientific goals. To accomplish current requirements of the scientific community biobanks need to face some essential challenges including an appropriate design, harmonized and more suitable procedures, and sustainability, all of them in the framework of their ethic, legal and social dimensions. This review therefore presents an overview on these issues, based on the works and discussions of the Marble Arch International Working Group on Biobanking for Biomedical Research, integrated by experts in biobanking from five continents.