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Optimized Biopsy Preservation for Clinical Gene
Expression and Profiling
RNAlater® Tissue Collection: RNA
Stabilization Solution is an aqueous tissue storage reagent that
protects RNA within intact, unfrozen tissue samples. RNAlater Solution
was designed to eliminate the need to immediately process tissue
samples or to freeze samples in liquid nitrogen for later processing.
This has proved advantageous in situations in which sample deep
freezing methods are not convenient and sample numbers are large,
e.g., when sampling a large number of patients in a clinical
setting. In the studies described below, Drs. Cui and Gardner
both use RNAlater Solution to store and stabilize clinical
skin biopsy samples, utilizing gene expression analysis via real
time RT-PCR and array analysis, respectively.
RNAlater® Solution Preserves Colorectal
Biopsy Samples for Real-time PCR Studies
Monitoring changes in mRNA expression levels
aids in understanding the pathogenesis of inflammatory bowel
disease. While real-time PCR has become a convenient method for
measuring mRNA expression, it requires high quality RNA to get
consistent and reproducible results. Dr. Cui and colleagues (University
of Tromse, Norway and University Hospital of North Norway) were
optimizing their laboratory procedures for endoscopic biopsy
sampling and technique to preserve RNA integrity during transport
for subsequent use in real-time PCR experiments [1]. Samples
from five patients were preserved in RNAlater® Solution at
room temperature, and RNA integrity was compared in samples that
had been stored for one hour vs. eight days.
The integrity of RNA from samples stored for
eight days (RIN=8.50 ± 0.42) in RNAlater Solution was
comparable to that from samples stored for just one hour (RIN
= 9.04 ± 0.27) indicating that RNA remained undegraded
during transport in RNAlater Solution even after eight days at
room temperature. The stability afforded by RNAlater Solution
improved the clinical use of real-time PCR for quantification
of TNF-α gene expression in these colorectal biopsies.
RNAlater® Solution Stabilizes and
Preserves Scleroderma Skin Samples for Gene Profiling with Affymetrix
Arrays
When collecting numerous samples for gene expression
profiling studies, it is critical to control for variation introduced
by different sample collection methods and subsequent RNA preservation.
Dr. Gardner and colleagues (Cambridge Massachusetts, Medical
University of South Carolina, Warsaw Medical Academy, Poland,
and University of Texas Medical School at Houston) addressed
whether biopsy specimens obtained from systemic sclerosis lesions
exhibited a gene profile that was distinct from fibroblast cultures
[2]. In his study, Dr. Gardner controlled for the variable sources
of RNA collection and preservation conditions by storing the
biopsy samples and fibroblast cultures in RNAlater Solution prior
to RNA isolation. The purified RNA from the scleroderma biopsies,
control skin biopsies, and four control explanted fibroblasts
from nine patients and nine controls were subsequently hybridized
to Affymetrix® arrays.
The results from RNAlater Solution-treated
tissue indicated that scleroderma has a distinct gene profile
that is incompletely reflected in profiles from fibroblast cultures.
Results confirmed a constant yet different expression pattern
across the controls, indicating that RNAlater Solution can stabilize
RNA for subsequent gene profiling. RNAlater Solution provides
flexibility for sample collection and storage, and helps ensure
that high quality RNA is preserved in samples.
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