Q.Give one example each of a disease or condition where stem cell therapy is being explored or used, and briefly state the underlying idea of how it may help.

[!TLDR] Example: bone-marrow stem cell transplantation for certain blood cancers/immune disorders -- healthy donor stem cells replace the patient's diseased blood-forming cells. …

One of the most well-established and widely used forms of stem cell therapy in current medical practice is bone-marrow stem cell transplantation, used to treat certain blood cancers (such as some forms of leukaemia) as well as certain severe immune disorders.

The underlying idea is straightforward: a patient's own bone marrow, which normally contains the blood-forming (haematopoietic) stem cells responsible for continuously producing all the different types of blood cells throughout life, may in these conditions be producing diseased, cancerous, or otherwise dysfunctional cells instead of healthy ones. By first eliminating the patient's existing, diseased bone-marrow cell population (typically using chemotherapy and/or radiation) and then introducing healthy haematopoietic stem cells -- either from a suitably matched donor, or in some cases from the patient's own previously collected healthy cells -- into the patient's body, these transplanted healthy stem cells can settle into the bone marrow and begin dividing and differentiating there, gradually repopulat …

Pick one specific, well-established real example (bone-marrow transplantation) and explain the underlying self-renewal/differentiati …

Do not confuse bone-marrow stem cell transplantation with an ordinary blood transfusion -- a transplant introduces self-renewing STEM CELLS that go on to produce new blood c …