(Fast-Track proposals will be accepted.)
Budget (total costs): Phase I: $200,000
for 6 months; Phase II: $1,500,000 for 2 years
Number of anticipated awards: 3
It is strongly suggested that proposals
adhere to the above budget amounts and project periods. Proposals
with budgets exceeding the above amounts and project periods may not
be funded.
Summary
Red blood cell (RBC) products for
transfusion undergo metabolic and physical changes in both the
cellular and plasma fractions during storage (RBCs can be stored up
to 42 days currently) which may be associated with non-infectious
risks and reduced tissue oxygenation capacity. The changes that
occur during storage have been referred to in the literature as the
RBCs Òstorage lesionÓ. Many of these changes have been characterized
and include increasing levels of microparticles and potassium; free
hemoglobin release; decrease in pH, adenosine triphosphate, and
2,3-diphosphoglycerate; loss of RBC membrane flexibility; and
changes in enzymatic functionality resulting in a loss of nitric
oxide (NO) signaling. Current research suggests that the storage
lesion may result in extravascular hemolysis and inflammation,
vasoconstriction, and potentially suboptimal tissue oxygenation.
Many retrospective and prospective studies, including a recent
meta-analysis of 21 studies, have demonstrated that the transfusion
of RBC units which have been stored for longer periods (up to 42
days) appears to be associated with increased recipient morbidity
and mortality; but these associations may be confounded by severity
of illness. Two large blinded, multi-center randomized trials are
currently underway in the United States and in Canada to determine
if ÒyoungerÓ vs. ÒolderÓ or Òstandard ageÓ blood is equally safe and
effective in complex cardiovascular surgery and ICU patients,
respectively, but the results of these studies will not be known for
several years.
While it is unclear at this stage whether
the RBC storage lesion results in serious adverse clinical outcomes
in transfusion recipients, it would seem biologically plausible that
a reduction in the number of potentially toxic elements in RBC
supernatants, as well as an increase in the concentration of
well-preserved RBCs, would be beneficial in many ways. These
potential benefits could include 1) improved effectiveness of RBC
products; 2) markedly reduced adverse events; and 3) optimal tissue
oxygenation by fully functioning RBCs. Developing improved blood
bank storage and transfusion processes and practices to mitigate the
RBCs Òstorage lesionÓ, improve the effectiveness of transfusion, and
safely maintain the shelf-life of RBC components at or near the
current FDA mandated maximal storage limit of 42 days, will be
important to assuring blood availability for future public health
needs.
There is scientific evidence that some of
the RBC storage lesion changes might be reduced, restored or
mitigated by changes in blood storage conditions and/or through
manipulation prior to transfusion with processes such as washing,
filtration and/or renitrosylation. Multiple strategies may be needed
because targeting any single parameter may be insufficient to
markedly improve RBC product quality.
The National Blood Collection and
Utilization Survey Report estimates that a total of 17.3 million
blood units were collected and 14.6 million RBCs units were
transfused in the United States in 2008. Except for pediatric
transfusions, blood banks always deliver the oldest available RBC
units when a RBC transfusion is requested to optimize their
inventory management. It is anticipated that a product and/or
process developed for this contract topic could be utilized by all,
or a portion of, the patients needing a transfusion in the U.S. and
internationally. Depending on the product, the market may be any or
all of the following: blood centers, blood banks, and hospitals as
these are the facilities that collect, produce and/or transfuse RBC
component units.
Applicants are encouraged to explore
utilization of the NHLBI SMARTT program (