Regenerative or reparative medicine Essays - Medicine, Biology

Regenerative or reparative medicine leukaemia : Figure SEQ Figure \* ARABIC 1 :comparison between blood of normal person and other with leukemia Leukaemia is a cancer of the blood and bone marrow. It causes white blood cells (also called leukocytes) to develop abnormally. White blood cells are made in the bone marrow and their main job is to defend the body against infection and disease. In most forms of acute leukaemia the body produces large numbers of abnormal white blood cells which look like immature cells called blasts. These leukaemic blasts accumulate in the bone marrow and suppress the formation of normal white blood cells. Leukaemias are grouped according to the severity of the disease (how fast it is growing) and the types of white blood cells affected: Acute leukaemias Chronic leukaemias There are also less common types and subtypes of leukaemia . Causes of leukaemia : Like most cancers, leukaemias are caused by a series of rare mutations (changes) in the genes inside certain cells. Occasionally, one of these mutations may be inherited and then the individual is predisposed to develop leukaemia . Other known causes include accidental exposure to radiation and treatment with some types of anti-cancer drugs. However, most leukaemias are caused by an accumulation of mutations that occur naturally - mistakes which happen during the production of new cells in the body. A large number of gene mutations have been linked to human leukaemias , but in most cases it is not yet known which ones really drive the disease. Chronic myeloid leukaemia (CML) is caused by a single genetic change but most other leukaemias appear to be more complicated and may involve combinations of mutations. Many types of leukaemia are thought to originate in blood stem cells, also called haematopoietic stem cells (HSCs). HSCs are responsible for making new blood cells in our bodies all our lives. If a stem cell is affected by genetic changes, all the cells it produces will inherit the same mutation. It has been shown that CML starts with a particular mutation in HSCs. However, cells go through a number of steps to develop from HSCs into specialised cells such as white blood cells. Mutations might happen at any of these steps. For many leukaemias , a complex series of events is probably involved and it is not yet clear where the first important mutation occurs. Healthy blood stem cells which are used to treat leukaemia : Acute leukaemia usually requires immediate and intensive treatment. Depending on the particular type of leukaemia and many other things about the individual patient, treatment options might include chemotherapy, steroids or a more intensive procedure such as a haematopoietic stem cell transplant combined with high-dose chemotherapy. High-dose chemotherapy is the most effective currently established method to kill leukaemic cells and can cure some patients. However, it also severely damages the remaining normal blood-forming cells in the bone marrow. To replace these cells, patients are given a haematopoietic stem cell transplant (HSCT). The cells for the transplant can be collected from the blood or bone marrow of a healthy donor. In fact, the transplant includes not only HSCs, but also important immune cells that help to kill leukaemic cells. A patient's own cells can sometimes be used for the transplant, if it is possible to collect enough healthy cells before the treatment is performed. If a different donor is needed, they must match the patient's tissue type otherwise the transplanted donor cells will be attacked by the patient's immune system and rejected. HSCTs are particularly effective for treating certain types of acute leukaemia . However, the procedure is intensive and risky with the potential for substantial after effects. Therefore, this type of stem cell transplant is only considered when standard-dose chemotherapy fails to eradicate the disease. Recent developments and current research on haematopoietic stem cell treatments for leukaemia : The high dose of chemotherapy given to leukaemia patients before a transplant destroys both leukaemic cells and healthy bone marrow cells. Newer forms of transplantation called mini-allografts or reduced-intensity allografts have been developed to reduce the risk. These procedures allow lower doses of chemotherapy to be used, which helps avoid extensive damage to the bone marrow. Instead,