It has been long known that people who receive blood transfusions have a higher chance of having all kinds of medical problems following the transfusion. Research coming out of Duke now shows that stored blood loses a great deal of its nitric oxide content which is critical in oxygen transfer from blood to tissues.
Almost immediately after it is donated, human blood begins to lose a key gas that opens up blood vessels to facilitate the transfer of oxygen from red blood cells to oxygen-starved tissues.
Thus, millions of patients are apparently receiving transfusions with blood that is impaired in its ability to deliver oxygen, according to Duke University Medical Center researchers, who reported the results of their studies in two separate papers appearing early on-line in the Proceedings of the National Academy of Sciences.
They also found that adding this gas back to stored blood before transfusion appears to restore red blood cells’ ability to transfer oxygen to tissues. These studies go a long way toward answering a major problem which many physicians are beginning to appreciate – blood transfusions with banked human blood may do more harm than good for a majority of patients, according to the researchers.
Over the past five years, many studies, including some performed at Duke, have demonstrated that patients who receive blood transfusions have higher incidences of heart attack, heart failure, stroke and even death. While it is known that the banked blood is not the same as blood in the body, the reasons behind blood’s association with worse outcomes have not been well-understood.
The key to the current findings is that nitric oxide in red blood cells is crucial to the delivery of oxygen to tissues. Nitric oxide keeps the blood vessels open. The new studies demonstrated that nitric oxide in red blood cells begins breaking down almost immediately after red blood cells leave the body.
“It doesn’t matter how much oxygen is being carried by red blood cells, it cannot get to the tissues that need it without nitric oxide,” said Duke’s Jonathan Stamler, M.D., senior author of one of the PNAS papers, whose group originally discovered the role of red blood cell nitric oxide in oxygen delivery. “Nitric oxide opens up the tiny blood vessels, allowing red blood cells to pass and deliver oxygen. If the blood vessels cannot open, the red blood cells back up in the vessel and tissues go without oxygen. The result can be a heart attack or even death.
“The issue of transfused blood being potentially harmful to patients is one of the biggest problems facing American medicine,” continued Stamler, who is a professor of cardiovascular and pulmonary medicine. “Most people do not appreciate that blood has the intrinsic capacity to open blood vessels, thereby enabling oxygen to get to tissues. Banked blood cannot do this properly.”
Dr. Stamler explains the findings in this video released by Duke Med:
Press release: Banked Blood Loses Ability to Deliver Oxygen to Tissues …
Investigators from the National Synchrotron Light Source at the Brookhaven National Laboratory were able to marry two different imaging modalities–synchrotron-based infrared (FTIRM) and x-ray fluorescence (XRF) microscopies–to better understand organic composition and trace metal content of specimens. According to the researchers, their technique could aid in our understanding of processes behind such things as Alzheimer’s disease and the physiology of metal-reducing bacteria.
Broncus Technologies, Inc, a Mountain View, California company, has announced positive results in a study of their proprietary airway bypass procedure for people with emphysema.
The prospectively defined primary endpoint of this feasibility study was a reduction in residual volume (RV, the amount of air remaining in the lungs after full exhalation) at 6 months. The goal was for a 300mL reduction in RV. Overall the trial surpassed that goal with a 400mL improvement in RV over baseline at 6 months (p=0.04). Patients also showed a statistically significant improvement in the modified Medical Research Council Dyspnea Scale (mMRC), a breathlessness test, of -0.5 points (p= 0.025). Retrospective analysis revealed that patients with the most severe hyperinflation of their lungs (as determined by a residual volume to total lung capacity ratio above the median) derived the greatest benefit from airway bypass. At 6 months after the procedure, these patients showed a mean improvement in RV of 870mL (p=0.022).
Scientists from the University of Pittsburgh filed a patent application for a pair glasses that monitor and auto trigger the eyelid to blink. The device one day might become useful for people with central and peripheral neurological damage, who have either absent or diminished eye-blink reflex..
But it allows the wearer to lift a person as heavy as 100 kilos as if they were carrying only half that weight.
Researchers at the University of Washington developed a simple, intuitive piece of software for controlling computer applications using nothing but voice. Using vocal control of the mouse, a person is able to interact with browsers and other programs with little to no training.
Using patients’ own skin cells, scientists were able to grow tissue-engineered blood vessels in vitro, then implanted them in renal patients as AV fistulas. The engineered blood vessels performed well in a study of six patients over a 3 month period, scientists are reporting in the latest issue of New England Journal of Medicine. The group of scientists are from Cytographt Tissue Engineering of Novato, California, that developed the technique, and worked with doctors in Argentina to test the technology.
Ten patients receiving hemodialysis whose arteriovenous shunts were failing were enrolled in this study. The subjects had typical risk factors for end-stage renal disease, including previously failed dialysis-access grafts, diabetes, controlled hypertension, and obesity. Patients ranged in age from 29 to 89 years (mean [±SD], 68±17). Vessel patency was evaluated by means of Doppler and angiographic imaging. Mechanically viable vessels were created with autologous cells for each patient. The average burst pressure among 54 vessels was 3340±849 mm Hg, which compares favorably with native veins.3
Stanford scientists have filed a patent application for a heart corset designed to limit the detrimental cardiac enlargement that often accompanies a heart failure.
