Congenital Heart Defect: Stem Cells Develop Replacement Heart Valves

Most common type of birth abnormality (physical or mental) is congenital heart defect and leading cause of related deaths. During early weeks of pregnancy, congenital heart defects or disease (CHD) occurs because of incomplete or abnormal development of the fetus heart before birth. The abnormality can be of any one of many defects in the heart, including the walls of the heart, the valves of the heart, and the arteries and veins near the heart. Blood flow can slow down, go the wrong direction, to the wrong place or be blocked completely. The cause is either attributed to genetic disorder, such as Down - Syndrome or in most cases unknown. However, medical professionals would agree, contributing to the cause of CHD, environmental factors, women who contract rubella (German measles) during the first three months of pregnancy, chronic illnesses (Including diabetes), viral infections, taking certain types of medication during pregnancy (Including acne medication), exposure to industrial chemicals, drinking alcohol during pregnancy, and smoking during pregnancy (According to American Heart Association, pregnant women risk having a baby with congenital heart defect by 60 to 80 percent. Also, second hand smoke attributes to this disease by 30 percent.) According to Dr. Sadik Malik, a pediatric cardiologist at the University of Arkansas for Medical Sciences, said: " 2,000 congenital heart defects could be prevented each year if women stopped smoking before they try to become pregnant." The abnormality to the heart maybe detected with ultrasound test, about 20 weeks into the pregnancy. However, in some cases the ultrasound may not detect an abnormality, until it becomes present sometime in the future or later in life. In the United States, each year more than 30,000 babies are born with congenital heart defects or one out of every 125 (According to March of Dimes).

Symptoms synonyms or attributed to congenital heart disease: When a physician or health care provider, hears an abnormal sound (from the baby's heart), referred to as a murmur, suggest tests (Including ultrasound, Echocardiography and cardiac magnet resonance imaging (MRI)) to confirm or rule out a heart defect. Also, difficulty feeding in infancy, sweating, cyanosis (blue discoloration caused by a less oxygen), respiratory infections that recur excessively, stunted growth and underdevelopment of limbs and muscles.

Available are a variety of treatment options for congenital heart disease, including medication and/or surgery. Each type of treatment depends on diagnosing the cause of CHD. There are more than thirty-five common congenital heart defects. Surgical procedures seek to repair the defect by restoring as much blood circulation as possible and may require additional future surgeries.

A type of congenital heart defect: One or more heart valves (Four major valves of the heart - two atrioventricular (AV) and two semilunar (SL) valves) can't open or close correctly, depending on the difference in pressure on each side: Blood can't flow smoothly. This prevents oxygen poor blood from circulating to the lungs. Conventional treatment options are considered but each has a drawback. Implanting an artificial valve(s) are prone to blood clots and patients must take anti-clotting medication for life. Transplanted values from human cadavers or animals over period time could deteriorate requiring open - heart surgery to replace them. Especially, concern for children because the valves don't grow along with the body. Dr. Smith Hoerstrup, University of Zurich scientist who led the work of his colleges, presented on November 15, 2006, at an American Heart Association conference, first time revolutionary approach to repair defective heart valves, by growing human heart valves using stem cells from the amniotic fluid that surrounds the fetus. A common prenatal test for birth defects for women aged 35 and older, during amniocentesis, a needle is inserted into the womb and small amount of amniotic fluid is removed and tested, under ultrasound guidance. The procedure has a small risk of miscarriage (1 in 200 or less). Developing human heart valves starts by isolating from the amniotic fluid fetal stem cells, which are cultured in a lab dish and then placed on a mold shaped like a small ink pen, and made of biodegradable plastic. Within four to six weeks, during the experiment, each of the twelve heart valves where created. Dr. Hoestrup said: "amniotic stem cells can be frozen for years and could potentially be used to create replacement parts for aging or diseased valve in adults, too." "At least one-third of afflicted infants have problems that could be treated with replacement valves." Also, "amniotic fluid is potentially a richer source of stem cells than other sources. " According to CO-researcher and Dr. Hoestrup: "A promising, low-risk approach enabling the prenatal fabrication of heart valves ready to use at birth." Heart valves grown in the laboratory for infants and adults are more durable and effective than artificial or cadaver valves. Scientist Hayashida at the National Cardiovascular Center Research Institute in Oska, said: "Valves made from the patient's own cells are living tissue and might be able to grow with the patient." Ethically, procedure has an advantage, because using the cells the fetus sheds in amniotic fluid, avoids controversy that involves destroying embryos to get stem cells. During the next two years, the experiment will examine the effectiveness of this procedure on sheep. Implanting tissue engineered human valves in human hearts is likely years away, and most certainly would require approval from the Food and Drug Administration. During the American Heart Association conference, according to Dr. Kyoko Hayashida, leading author described how Japanese researchers had grown new heart valves in rabbits, using cells from the animal's own tissue. This was the first time replacement heart valves where created.

In 2005, researchers reported that two kidney dialysis patients from Argentina had received the world's first tissue engineered blood vessels, created from their own skin and vein tissue.