Compositions, methods and apparatuses for preserving platelets

Details Compositions, methods and apparatuses for preserving platelets Compositions, methods and apparatuses for preserving platelets

1999-03-11

2004-12-07

Wax, Robert A. (Department: 1653)

Chemistry: molecular biology and microbiology

Maintaining blood or sperm in a physiologically active state...

C424S532000

Reexamination Certificate

active

06828090

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to compositions, methods and apparatuses for preserving biological materials. More particularly, the invention relates to compositions, methods and apparatuses for the extended storage of platelets.
BACKGROUND OF THE INVENTION
Over the last 40 years the need for the therapeutic use of biological materials, such as blood, skin and other tissues, kidneys, hearts, livers and other body organs has increased dramatically. Blood and plasmas components, including red cells, platelets, clotting factors, albumin, and antibodies are isolated and used to treat various bleeding problems. In particular, platelets, essential components of the human blood, are used extensively for assisting in the control of bleeding and replacing functionally defective platelets in patients. For example, platelet transfusions are required by trauma patients who have lost significant amount of blood, patients undergoing chemotherapy that reduces the number of platelets and causes functional defects in remaining platelets, and patients with certain platelet-depleting diseases.
Constituents in whole blood include leukocytes (white blood cells), erythrocytes (red blood cells), thrombocytes, platelets and plasma. Platelets are not entire cells but small detached cell fragments or “minicells” derived from the cortical cytoplasm of large cells called megakaryocytes in the bone marrow. Platelets comprise an outer membrane and cytoplasm from the megakaryocytes which contain granules, dense bodies, dense tubular system and mitochondria. Platelets adhere specifically to the endothelial cell lining of damaged blood vessels, where they trigger and participate in hemostasis, or clotting, and release inflammatory mediators in response to contact with the endothelial cell lining. Important mediators released by platelets include serotonin and coagulation factors. Vascular breaches are repaired by platelets through adhesion and the response to damage is amplified by platelet secretions resulting in platelet aggregation and fibrin formation, i.e. stabilized clot.
It is very important to preserve platelets after their isolation from the body under conditions not only maintaining the biological activity of platelets but also suitable for clinical use. The average survival time for a platelet in the body after it leaves the bone marrow is 8-10 days. The average expected survival time for circulating platelets is 4-5 days, an average of the entire population. The average survival time for platelets after isolation from the body is about 5 days at room temperature.
The current standard and approved method for platelet storage is in a platelet bag at room temperature and limited to five days. The storage time is presumably limited by a decrease in pH due to increased lactate associated with anaerobic metabolic activity. Furthermore, the bag of platelets in plasma must be constantly in motion on a rocker to prevent aggregation. One of the disadvantages associated with preserving platelets under room temperature is the growth of bacteria in the platelet suspension. Platelets in a suspension stored in a refrigerator, albeit with suppressed bacteria growth, tend to activate upon contacting each other and aggregate.
Several approaches such as cryopreservation (freezing) techniques have yielded an increased number of platelets following storage. However, there is a limitation in the functional capacity and persistence of platelets in circulation that are recovered from such preservation conditions by using these methods. Freezing temperatures require the use of cryoprotectors such as DMSO (dimethyl sulfoxide) (Valeri, Feingold, and Marchionni, Blood, vol. 43, No. 1 (January)1974) and THROMBOSO™ to prevent damage to these biological materials. However, these cryoprotectors are cytotoxic, and typically leave a significant portion of the platelets with either reduced or no functional ability. Moreover, cryoprotectors usually require time-consuming preparation, such as rinsing processes, before the materials can be used, and cryoprotector residues often still remain afterwards. Freezing processes can store erythrocytes for more than 30 days, and leukocytes up to 12 hours only.
Other attempts to preserve platelets have included adding platelets activation inhibitors (Bode, Holme, Heaton and Swanson, Vox Sang, 60: 105-112 (1991); U.S. Pat. No. 5,622,867) or gelatin into the preservation medium (U.S. Pat. No. 2,786,014).
A need continues to exist for a storage system that will store biological materials, particularly platelets, for an extended period of time and still maintains their viability and bioactivity.
SUMMARY OF THE INVENTION
The present invention relates to compositions, methods and apparatuses for the extended storage of biological material and, in particular, platelets.
According to one embodiment, a platelet composition suitable for direct transfusion into a patient is provided comprising: a preservation medium comprising plasma and a gel-forming material in a concentration relative to the plasma such that the medium is in a sufficiently fluent state at a first temperature to allow platelets to move within the medium and is in a sufficiently gelatinous state at a second, lower temperature to substantially prevent platelets from moving freely within the medium; and platelets.
According to this embodiment, the first temperature is preferably about 37° C. and the second temperature is preferably about 5° C.
According to another embodiment, a platelet composition suitable for direct transfusion into a patient is provided comprising: a preservation medium comprising plasma and a gel-forming material in a concentration relative to the plasma such that the medium is in a sufficiently fluent state at a first temperature to allow platelets to move within the medium and is in a sufficiently gelatinous state at a second, lower temperature to substantially prevent platelets from moving freely within the medium; and platelets which have been stored within the preservation medium in a gelatinous state for at least 3 days where at least 50% of the platelets are intact and functional after the at least 3 days.
According to this embodiment, the first temperature is preferably about 37° C. and the second temperature is preferably about 5° C.
Also according to this embodiment, the platelets may be stored within the preservation medium for at least 5 days, more preferably at least 7 days. Also according to this embodiment, the platelets may be stored within the preservation medium for between 3 and 20 days, more preferably between 5 and 20 days. Longer storage of platelets is also possible.
Also according to this embodiment, the platelets may be stored within the preservation medium at a temperature less than 10° C. and preferably between −10° C. and 10° C. In one variation, the platelets are stored at a temperature between 0° C. and 10° C. at 1 ATM, more preferably at a temperature between 0° C. and 5° C. at 1 ATM. In another variation, the platelets are stored within the preservation medium at a temperature between −10° C. and 0° C. at a pressure greater than 10 ATM, more preferably at a temperature between −8° C. and −2° C. at a pressure greater than 10 ATM.
According to another embodiment, a platelet composition suitable for direct transfusion into a patient is provided comprising: a preservation medium comprising plasma and a gel-forming material in a concentration relative to the plasma such that the medium is in a sufficiently fluent state at a first temperature to allow platelets to move within the medium and is in a sufficiently gelatinous state at a second, lower temperature to substantially prevent platelets from moving freely within the medium; and platelets which have been stored within the preservation medium in a gelatinous state for at least 1 day at a pressure of at least 10 ATM and a temperature below 0° C. where at least 50% of the platelets are intact and functional after the at least 1 day.
According to this embodiment, the first temperature is preferab

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