Evaluation of Tissue Metabolites with High Resolution Magic Angle Spinning MR Spectroscopy Human Prostate Samples After Three-Year Storage at -80 degrees C.
Author(s): Jordan KW, He W, Halpern EF, Wu CL, Cheng LL
Publication: Biomark Insights, 2007, Vol. 2, Page 147-54
PubMed ID: 19662199 PubMed Review Paper? No
Purpose of Paper
This paper investigated the effects of long-term storage of prostate gland specimens at -80°C on metabolites measured by high resolution magic angle spinning (HRMAS) magnetic resonance (MR) spectroscopy.
Conclusion of Paper
Storage of prostate gland specimens for up to 32 months at -80°C did not significantly affect metabolite concentrations or spectra profiles when analyzed by HRMAS MR spectroscopy. Histopathology evaluation determined that variations in metabolite profiles between case-matched specimens stored at -80°C for different durations were due to tissue heterogeneity.
Studies
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Study Purpose
This study investigated the effects of long-term storage on tissue metabolites when measured by high resolution magic angle spinning (HRMAS) magnetic resonance (MR) spectroscopy. Eleven prostate specimens were collected from five prostatectomy cases in 2002 from different prostatic zones (central, transitional and peripheral). Case-matched specimens were snap-frozen and stored at –80°C for less than 24 hours or for 32 months (July 2002 to March 2005) and metabolite concentrations were analyzed using HRMAS MR spectroscopy. After spectroscopy analyses, specimens were fixed in formalin, embedded in paraffin, cut into 5 µm sections, and stained with Hematoxylin and Eosin for histopathology evaluation. No histologically visible cancer cells were visible in any of the specimens examined.
Summary of Findings:
Metabolite profiles obtained by HRMAS MR spectroscopy revealed few differences between adjacent tissues analyzed after less than 24 hrs and those stored for 32 months at –80°C. Quantitative histopathology revealed that variations in metabolite profiles were due to specimen heterogeneity; specifically, differences were in the volume percentage ratios between epithelial cells and stromal cells. A linear and very strong correlation was present among metabolite intensities quantified in prostate tissue analyzed after less than 24 h after freezing or after 32 months at -80°C when the sample set was limited to the seven cases that displayed less than 20% relative pathological variation between case-matched pairs (r2=0.823, P<0.001). In this sample set, no significant change in concentration following 32 months of cryostorage was found for the 21 metabolites evaluated, which included alanine, phosphocholine, and choline; suggesting a lack of tissue and protein degradation.
Biospecimens
Preservative Types
- Frozen
- Formalin
Diagnoses:
- Normal
Platform:
Analyte Technology Platform Small molecule Spectrophotometry Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Storage duration <24 hrs
32 months