What is stem cell therapy?
Q: What is stem cell therapy and how effective is it? Is there any recorded evidence of its success? Is it regulated in India by the government?
A:From a strictly biological point of view, a stem cell is a cell derived from an egg after fertilization (embryonic stem cell), which has the capability to divide indefinitely and generate every tissue that constitutes an adult organism. But cells with somewhat similar properties have also been identified and harvested from adult animal and human organs (adult stem cells) such as heart, muscle, brain, blood or bone marrow These have been cultured in the laboratory for long periods of time (under very strict and specified conditions) while retaining their ability to differentiate into the tissues from which they were initially harvested. Human cord blood also contains a large number of haematopoietic progenitor cells that can be used as a source of stem cells for treatment of blood disorders and cancers (cord blood stem cells). There is a lot of literature regarding claims that these cells possess remarkable plasticity i.e. the ability to differentiate from one structure into a completely unrelated structure but it is prudent to be cautious, as the reproducibility of these claims is yet to be determined in rigorous peer-reviewed fashion. These cells are very few in number, difficult to find and their characterisation remains incomplete. As they are harvested in small numbers and often need to be propagated in tissue culture for long periods of time, it is often clinically impractical. Moreover, it is not yet known if this can lead to potentially damaging changes. It is important to note the fact that when autologous (self) cells are used, they may actually carry the same genetic flaws that predisposed the host organism to the disease process in the first place. Stem cell work is still quite experimental but is very promising as many beneficial therapies are thought to exist with much scientific value being ascribed to them. Various centres in the world have been reporting their use in Parkinson's disease, heart disease, endocrine disorders, etc. but this is still not being done routinely or being offered as a therapeutic modality. Clinical efficacy is currently limited to bone marrow transplant, grafting new skin cells to treat burns, regenerating cornea in visually impaired, etc. Its potential use includes cures for cancer and treatment of neurologic, cardiac, renal, and endocrine (diabetes) diseases. There are still many difficulties in the routine use of stem cells and they include problem in identifying stem cells in tissue cultures, which contain numerous types of cells; to coax the cell to develop into a desired cell; integrating the new cells into the patient's own tissue, both structurally and functionally; preventing tissue rejection and the possible risk of cancer. As per the ICMR guidelines, as of date, there is no approved indication for stem cell therapy as a part of routine medical practice, other than bone marrow transplantation (BMT). Accordingly, all stem cell therapy other than BMT (for accepted indications) is treated as experimental. Institutions registered with the ICMR can enroll patients in clinical trials. There is no national policy to encourage people to store cord blood stem cells though several private storage cord blood banks exist that will store a baby's cord blood for use by that individual or a designated family member but they charge a heavy fee for this. In the West, where stem cell banks have been in existence for several years, doctors advocate public banking for the storage of cord blood but this is not yet available in most areas. Most doctors, therefore, do not recommend going to a private bank because saving cord blood for many years is extremely costly and the odds for its use are low. Estimates of the likelihood of a child needing its own stored cells later in life are low ranging from 1 in 1,000 to 1 in 200,000 by age 18 years. The American Academy of Pediatrics states: "Given the difficulty in estimating the need for using ones own cord blood cells for transplantation, private storage of cord blood as 'biological insurance' is unwise. However, banking should be considered if there is a family member with a current or potential need to undergo stem cell transplantation". The American College of Obstetrics & Gynaecology believes that many questions about this technology remain unanswered and recommends that parents should not be sold this service without a realistic assessment of their likely return on the investment. The advertising by commercial cord blood banks stating it as part of doing everything possible to ensure the health of children is unethical as it makes parents feel guilty if they are not eager or able to invest considerable sums in such a highly speculative venture.