Extend Life of Platelets and Prevent Bacterial Infection

Platelets (thrombocyte) are cell fragments (Has no definite nucleus) circulating in the blood, minute, irregularly shaped, and dislike cytoplasmic body. Thrombocyte are produced in the bone marrow (Medulla osea - Soft tissue found in the hollow interior of bones, includes the breast bone, hips, ribs, skull which contains stem cells. These stem cells produce new blood cells (red and white blood cells and platelets)), and stored in the spleen (Blood filtering organ located in the upper left part of the abdomen near the stomach. Functions of the spleen include: Clears or destroys worn out and damaged red blood cells and platelets). Platelets are important to form clots or coagulation (Clots prevent blood loss from a ruptured blood vessel or stop bleeding). In an adult, normal platelet count about 150,000 - 450,000 per microliter of blood. If the platelet levels falls below 200,000 per microliter, spontaneous bleeding may occur and considered life - threatening risk. A low platelet count attributed to one of many medical conditions: Decrease in the number of platelets (thrombocytopenia) attributed to bone marrow disease, such as leukemia or cancer in the bone marrow. When the body's immune system creates antibodies that attack it's own organs (autominmune disorder such as lupus or Idiopathic Thrombocytopenia Purpura (ITP)), which cause the destruction of platelets. Certain drugs (heprin, oral anti -- diabetic drugs, and quinidine) and alcohol may decrease the number of platelets. Patients undergoing chemotherapy have a decrease in platelet count. Up to five percent of pregnant women my experience thrombocytopenia at term. Also, up to one percent of the population have an inherited disease attributed to a low platelet count.

Platelet count can be increased by strenuous exercise, living in high altitudes, and taking certain drugs such as estrogen and oral contraceptives.

Platelets live ten to twelve days in the bloodstream, and afterwards enter the spleen. The production of platelets is constant process. About two million people a year require platelet transfusions for reasons given for a low platelet count. A single treatment of platelet transfusion requires four to six pints of donated blood. In the United States, approximately twelve units of platelets are transfused each year, primarily for patients undergoing treatment for cancer, and especially patients receiving chemotherapy drugs, often require a transfusion, because the treatment effects bone marrow, from producing enough platelets to support clotting. Donated platelets are stored at room temperature in plasma and become useless after five days. However, platelets cannot be refrigerated, chemical changes occur (cold makes them vulnerable to immune system cells) which cause platelets to become useless for transfusion.

Researchers (Supported by a grant from Pall Corporation) at the Miami Hospital in Providence Rhode Island, reported in the May 2006 issue of Transfusion: Lead author Joseph Sweeney, M.D. director of transfusion services at The Mirriam Hospital and professor at Brown Medical School said: "We found that by storing the platelets in the artificial preservative we were able to retain the quality of the blood product for seven days, as opposed to having to dispose of them after five days." The preservatives are glucose (Previously glucose lowered the pH level (measure the acidity of a solution) which made platelets useless), sodium acetate and sodium bicarbonate. The combination of sodium acetate and sodium bicarbonate prevent platelets from exposure to low pH level. Replacing platelets with artificial preservatives, instead of plasma, patients experience fewer adverse reactions or better tolerate the new blood product. Sweeney said: "Advances in platelet storage will pave the way for the next generation of blood products, such as artificial platelets."

In the March 23, 2007, issue of the journal Cell, published by Cell Press, Australian scientists reported their findings that greatly extend the life of platelets. Research team led by Dr. Benjamin Kile and David Huang discovered platelets life span is controlled by two key molecules (proteins) that act in opposition to each other, by regulating the process known as apoptosis (Refers to the normal and healthy destruction of old, damaged and surplus cells). One protein (Bcl-xL) functions to preserve the life of a platelet, and the other opposing protein (Bak) prepares the cell to self-destruct, after its usual life (about week) within the body. Dr Kile said: "For fifty years doctors have speculated about what controls platelets life span. We now know the identity of the precise molecular switch responsible. The team is now actively pursuing a drug development program aimed at manipulating this switch in order to prolong the life span of blood bank platelets, increasing their availability to patients receiving cancer treatment and others in danger of serious bleeding". David Huang said: "If the platelet storage time could be extended from five to eight or 10 days, it would make a lot of difference for clinical and blood banking practice." The team of researchers discovered "BH3 mimetic" drug, which targets bcl-xL, and a class of anticancer therapy, currently under development. When the drug was administered to mice, Bak was eliminated and mice lived longer than normal. Longer living platelets offer the benefits for longer storage - time, survive longer in patients, and fewer number of transfusions are required.

Experts estimate one in every 1,000 to 2,000 units of platelet transfusions are contaminated with a bacteria; greatest risk for a lethal infection or sepsis (Illness caused by a severe infection, enters the bloodstream by toxin producing bacteria). On March 1, 2004, AABB (formerly the American Association of Blood Banks) adopted a new standard that requires member blood banks and transfusion services to implement measures to detect and limit bacterial contamination in all platelet components. In March 2007, Verax Biomedical Incorporated submitted an application to the Food and Drug Administration, seeking approval for an updated test (Platelet PGD Test) for the detection of bacterial contamination in platelets. Platelet PGD Test detection time, approximately thirty minutes, compared to the current available tests, takes one to three days. Also, platelet PGD test targets all species of bacteria known to cause diseases in humans compared current culture testing methods, miss at least half of all bacterial contaminations. Abbott Diagnostics plans to market and distribute the product worldwide.