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More than 60 years ago, scientists discovered the underlying causeof sickle cell disease: People with the disorder producecrescent-shaped red blood cells that clog capillaries instead offlowing smoothly, like ordinary, disc-shaped red blood cells do.This can cause severe pain, major organ damage and a significantlyshortened lifespan. Researchers later found that the disease results from a singlemutation in the hemoglobin protein, and realized that the sickleshape - seen more often in people from tropical climates - isactually an evolutionary adaptation that can help protect against malaria . However, despite everything scientists have learned about thedisease, which affects 13 million people worldwide, there are fewtreatments available. "We still don't have effective enoughtherapies and we don't have a good feel for how the diseasemanifests itself differently in different people," says SangeetaBhatia, the John and Dorothy Wilson Professor of Health Sciencesand Technology and Electrical Engineering and Computer Science atMIT. Bhatia, MIT postdoc David Wood, and colleagues at HarvardUniversity, Massachusetts General Hospital (MGH) and Brigham andWomen's Hospital have now devised a simple blood test that canpredict whether sickle cell patients are at high risk for painfulcomplications of the disease. To perform the test, the researchersmeasure how well blood samples flow through a microfluidic device. The device, described March 1 in the journal Science Translational Medicine , could help doctors monitor sickle cell patients and determine thebest course of treatment, Bhatia says. It could also aidresearchers in developing new drugs for the disease. Monitoring blood flow Sickle cell patients often suffer from anemia because their abnormal red blood cells don't last very long incirculation. However, most of the symptoms associated with thedisease are caused by vaso-occlusive crises that occur when thesickle-shaped cells, which are stiffer and stickier than normalblood cells, clog blood vessels and block blood flow. The frequencyand severity of these crises vary widely between patients, andthere is no way to predict when they will occur. "When a patient has high cholesterol , you can monitor their risk for heart disease and response to therapy with a blood test. With sickle celldisease, despite patients having the same underlying geneticchange, some suffer tremendously while others don't - and we stilldon't have a test that can guide physicians in making therapeuticdecisions," Bhatia says. In 2007, Bhatia and L. Mahadevan, a Harvard professor of appliedmathematics who studies natural and biological phenomena, startedworking together to understand how sickle cells move throughcapillaries. In the current study, the researchers recreated theconditions that can produce a vaso-occlusive crisis: They directedblood through a microchannel and lowered its oxygen concentration,which triggers sickle cells to jam and block blood flow. For each blood sample, they measured how quickly it would stopflowing after being deoxygenized. John Higgins of MGH and HarvardMedical School, an author of the paper, compared blood samplestaken from sickle cell patients who had or had not made anemergency trip to the hospital or received a blood transfusionwithin the previous 12 months, and found that blood from patientswith a less severe form of the disease did not slow down as quicklyas that of more severely affected patients. No other existing measures of blood properties - includingconcentration of red blood cells, fraction of altered hemoglobin orwhite blood cell count - can make this kind of prediction, Bhatiasays. The finding highlights the importance of looking atvaso-occlusion as the result of the interaction of many factors,rather than a single molecular measurement, she says. To show that this device could be useful for drug development, theresearchers also tested a potential sickle cell disease drug called5-hydroxymethyl furfural, which improves hemoglobin's ability tobind to oxygen. Adding the drug to blood, they found, dramaticallyimproved how it flowed through the device. The researchers have applied for a patent on the technology and arenow working on developing it as a diagnostic and research tool. Additional References Citations. We are high quality suppliers, our products such as Dimmable Led Light Bulbs Manufacturer , China E27 Led Light Bulbs for oversee buyer. To know more, please visits E27 Led Lamps.
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