Blood Vessels

The artificial vessels created by Humacyte do not perfectly mimic nature's recipe. They lack a major component of natural vessels: the protein elastin. Scientists at the University of Pittsburgh have now coaxed engineered vessels to make elastin, they reported Feb. 3 in the online edition of the journal Proceedings of the National Academy of Sciences. The rubber-band material that allows veins and arteries to snap back into shape after every pulse, elastin has long been one of the greatest challenges in any attempt to make artificial blood vessels.

Heart bypass patients may soon be able to get new arteries without having to sacrifice vessels from other parts of their body, thanks to ready-made, off-the-shelf artificial blood vessels. Biomedical engineers have been trying to build replacement blood vessels, needed for coronary artery bypass surgery and kidney dialysis patients, for three decades. Researchers from Humacyte Inc., in Durham, N.C., discovered the trick: recruiting cells to build the vessel, then washing them away so the nonliving tissue is storable and works for anyone.

Surgeons could use artificial blood vessels in several ways: Coronary artery bypass grafts: If one of the heart's arteries is blocked or diseased, a new vessel may be necessary. Surgeons can harvest arteries and veins from elsewhere in the patient's body, but they're in limited supply. Peripheral bypass grafts: Atherosclerosis can narrow arteries beyond the heart. Again, the body has only so many options for replacement. Kidney dialysis shunts: People on dialysis need an easily accessible vessel containing fast-moving blood.

A novel theory about the cause of multiple sclerosis — one that quickly led to millions of dollars in research pledges and an increasingly popular, though unproved, treatment — took a hit Monday from two studies calling the premise into question. The theory, proposed last year, had gained traction in a field desperate for research advances. It suggests that multiple sclerosis can be traced to obstruction in the veins carrying blood from the brain back to the heart — leading to nervous system damage and causing the hallmark symptoms of muscle weakness, decreased coordination and vision problems.

A successful hand transplant has a long list of ingredients: a motivated patient; a team of plastic surgeons, orthopedists, neurosurgeons and others to reattach bone, ligaments, nerves and blood vessels; and a suitable donor hand that matches the patient's size, skin color and even hair patterns. The surgery, which can run as long as 14 hours, has been available for a little more than 10 years — the first successful hand transplant was performed in France in 1998, with the U.S. following a year later.

A stiffening of the aging brain's blood vessels reduces their ability to respond to changes in blood pressure, increasing the risk of falls by as much as 70%, researchers reported Monday. Although the change in the arteries is only one of many factors that lead to falls among the elderly, the findings provide a potential target for intervention, said Dr. Joe Verghese, a neurologist at Albert Einstein University College of Medicine who was not involved in the research. Treating high cholesterol, high blood pressure and diabetes, among other factors, can reduce the stiffening.

Contrary to speculation that actor Corey Haim died of a drug overdose, the Los Angeles County coroner's office announced Tuesday that the former child actor died of pneumonia . Neither illegal nor prescription drugs were a factor in the actor's death, the coroner's office found — a marked contrast to early reports from authorities. The autopsy found that Haim, 38, died of respiratory distress related to pneumonia with the presence of an enlarged heart and narrowing blood vessels.

Dozens of studies have reported a link between exercise and lowered blood pressure: Some have found reductions of up to 10 mm Hg (systolic) and 6 to 10 mm Hg (diastolic) blood pressure units in people who already have hypertension. In general, reductions are not as great for people with blood pressure in the normal range: A Belgian review of scores of studies found that for people with high blood pressure, average reductions from exercise were 6.9 mm Hg systolic and 4.9 mm Hg diastolic, and for participants who did not have high blood pressure, only 1.9 mm Hg and 1.6 mm Hg. Age seems to matter.

California researchers have developed a technique to grow artificial blood vessels from a patient's own skin cells -- a technique that could quickly find application in kidney-failure victims undergoing dialysis. The technique has been tested in 10 patients, and preliminary results published Thursday in the journal Lancet suggest that the blood vessels can remain viable for long periods. "This technology is very, very promising," Dr.