Research Overview

Stem cells are the source of all tissues of the body. Harnessing the potential of these cells may make it possible to develop new treatments for many diseases by replacing cells that are lost or damaged in the disease process. Transplants of bone marrow stem cells are already in widespread use and have saved countless thousands of lives. Future candidates for cell replacement therapy include the insulin-producing cells that are lost in type I diabetes, the midbrain dopamine neurons that degenerate in Parkinson's disease, and the myocardial cells that are lost following a heart attack.

Some organs contain stem cells that persist throughout adult life; they contribute to the maintenance or repair of those organs. However, not every organ has been shown to contain stem cells, and in general adult stem cells appear to have restricted developmental potential; they have only limited capacity for proliferation and can give rise only to a few cell types. In contrast, embryonic stem (ES) cells can divide almost indefinitely and can give rise to every cell type in the body, suggesting that they may be the most versatile source of cells for transplantation therapy.

The first human ES cells were derived from surplus embryos generated during in vitro fertilization (IVF) treatment. More recently, however, the technique of somatic cell nuclear transfer into unfertilized eggs offers the possibility of creating human ES cells whose genetic makeup matches that of the donor. In addition to providing a powerful research tool for understanding human disease, this approach may eventually allow patients to be treated with an unlimited supply of new cells that will be recognized as 'self,' thereby avoiding the serious problem of rejection by the body's own immune defenses.

As an alternative to transplantation therapy, it may also be possible in some cases to stimulate the adult stem cells that already exist within a damaged organ or tissue using growth factors or other agents; essentially, this approach is effectively a way of harnessing the body's own repair mechanisms to accelerate healing. To achieve this goal, we will need to discover much more about the natural biology of the different types of stem cells and to understand their actual and potential abilities to repair different types of damage.

The Harvard Stem Cell Institute ( HSCI ) is committed to exploring all of these approaches, including both embryonic and adult stem cells. Our overall aim is to bring stem cells to the clinic as quickly as possible for as many different diseases as possible. Achieving this will require advances on many levels, from basic biology to patient delivery systems. The Harvard community, comprising the university, the medical school, and 18 hospitals and research institutions, is one of the largest concentrations of biomedical researchers in the world and is well positioned to make this vision a reality.