“Borrowed Life”An Article on Medical Breakthroughs: Organ Transplant
... Initially, the T-cells of these mice recognized and prepared to attack the transplanted heart tissue. They didn’t attack, however, but killed themselves instead. Thus, the mice that received the drugs during the surgery accepted the cardiac transplant and survived. Untreated mice immediately rejected the transplanted heart and died. Interestingly, the researchers also observed that administration of two of the three drugs they used, CTLA4Ig and CD40L, in combination with Cyclosporin A, prevented the self-destruction of the T-cells and led to rapid cardiac transplant rejection. For this reason, the drugs currently given to patient may actually prevent immune tolerance to transplants. “One of the most important lessons from this study is that total immune suppression is not synonymous with acquisition of tolerance,” says one expert.” A total block of the immune system with drugs like Cyclosporin A prevents the natural immuno-regulatory pathways, which include T-cell apoptosis, from developing. He believes that the protocol should be successful in human transplant patients. Indeed, therapies designed to teach the immune system to ignore a transplanted organ are now on their way to clinical trials. You might have heard about cloning and clones. This medical breakthrough sounds like it belongs to the sci-fi movies. It is really existing but with a more technical name, therapeutic cloning. This process involves deriving stem cells, the body’s “magic” seeds, from human embryo. These stem cells turn into specialized cells of the body and can be transplanted to replace cells and eventually organs, lost to disease. At the end of 1998, a team of researchers announced that it had isolated human embryonic stem cells. At about the same time, a claim by another team of scientists said it had isolated human embryonic germ cells. Scientists had long sought to isolate the elusive cells but capturing them proved difficult. One reason for this difficulty is the existence of embryonic stem cells in original, undifferentiated state momentarily. Then they turn into various specialized cells of the body. The cells also need a highly specialized environment to keep them alive outside the body. The breakthrough was widely hailed as a pioneering event. It gave rise to the promise of great medical benefits, and the most far-reaching implication of the breakthrough is the possibility of growing customized tissue in the laboratory to replace damaged cells and eventually organs. James Thomson of the University of Wisconsin announced the isolation of human embryonic stem cells. His group worked with “spare embryos”, embryos donated for research by couples undergoing in vitro fertilization. An embryo forms when the sperm fertilizes the egg cell. After five to seven days, the embryo forms a blastocyst, a hollow sphere of about a hundred cells with a few cells clustered inside. The outer layer of the blastocyst, called trophoblast, is destined to form part of the placenta. The inside part, called the inner cell mass, is destined to become fetus. The Wisconsin team removed cells from the inner cell mass and directed them to grow. The other group, led by John Gearhart at Johns Hopkins University, isolated cells from five to nine-week old aborted fetuses. Such cells are referred too as embryonic germ cells because they come from a small set of stem cells set aside in the embryo and prevented from differentiating. Embryonic germ cells are destined to give rise to egg or sperm cells of the next generation. Both embryonic stem and germ cells are in principle, immortal. The scientists successfully created conditions required by the stem cells to reproduce over time without specializing. The so-called “immortal” stem cells generated by the scientists remained undifferentiated but continued to divide, producing a significant quantity of cells. In the early stages of embryonic development, cells are undifferentiated. Over the course of development, they irreversibly turn into mature specialized cells. They become differentiated; meaning they turned into one or another type of cells such as nerve cell or skin cell. Stem cells are pluripotent; meaning they can turn into many cell types. A stem cell soon develops after fertilization and differentiates into about 210 types of specific fetal stem cells. The stem cells turn into mature cells and make up all of the body’s tissues and organs. Only a few type of stem cells remain after birth, the reason why many of our organ cannot rejuvenate after serious disease or injury. Scientists believe that research on stem cells will ultimately lead to techniques for generating cells, which can be employed in therapies for many conditions when the tissue is damaged. Researchers are now on their way towards programming stem cells to become other kinds of human tissue. In the future, researchers plan to use these stem cells to repair damage caused by Parkinson’s’ disease, diabetes, and other afflictions. The research has the potential to revolutionize the practice of medicine and improve the quality of life. In the meantime, researchers may find themselves up against restrictions imposed by governments to address ethical concerns. The problems primarily concern the sources of stem cells – human embryo and fetuses. Many religious groups oppose the destruction of human embryos to harvest the stem cells inside. On the other side is the scientific aspect, which wants the work to proceed because of potential medical benefits. You might also have heard about “cyborgs”. A cyborg is a person whose physiological functions are aided by or dependent on a mechanical or electronic device. Cyborg technology or bionics has the most dramatic and profound impact on our health. Bionics is the science of designing and constructing artificial systems with the ability to imitate living systems. Bionic body parts are enabling people to extend their lives through artificial means. Doctors replace hearts, legs, arms and even blood vessels, with man-made component. each year many people all over the world receive a cardiac pacemaker, hip replacement, mammary prosthesis and plastic lens implant. Advances in artificial-organ technology are being made everyday. Recent application of bionics includes bionic hearts and bionic limbs. Barney Clark, the recipient of the world’s first artificial heart implant extended his life for 112 days. The artificial hearts was called Jarvik-7 artificial heart, named from its inventor, Dr. Robert Jarvik. The preferred treatment for people with congestive heart failure is a heart transplant. But waiting for a donor is crucial, because it takes time. While still waiting for the donor, an artificial pump is inserted to the patient. A current-type of artificial pump is known as Ventricular Assist Device (LVAD). This device is stitched into the left ventricle and into the aorta. VAD augments the failing heart’s pumping capacity while the patients await a new organ. When no donors are available, the last resort to ...