Stem cells promise to be a virtual Swiss army knife for medicine. Just as one handy tool can help fix a chair or adjust an engine, stem cells can replace cells that pump blood (myocytes in the heart), fight infection (white blood cells), prevent diabetes (pancreatic cells), and even think (neurons).

It may sound like science fiction, but in fact, during embryonic development, stem cells give rise to all the cells and tissues of the body. What’s more, in some adult tissues, stem cells generate replacements for cells lost to normal wear and tear, injury, or disease. After disease strikes, stem cells provide a means of recovering functions that have been lost. They also provide a powerful scientific tool to help us understand the mechanisms of healing. Studies over the past five years have repeatedly demonstrated the remarkable versatility of stem cells, making them perhaps the most exciting topic in current medical technology. Gladstone is committed to harnessing the potential of stem cells, and its researchers are well equipped to do so. Many are nationally

The prevalence of heart failure is increasing in the United States. Heart failure affects older individuals with a greater frequency than younger people Source: National Center for Health Statistics

recognized experts in the scientific aspects of the diseases that are most likely to respond to stem cell therapy, including heart diseases and degenerative diseases of the brain and central nervous system. Working together, these investigators have developed critical scientific resources for unlocking the secrets of diseases.

A Medical Toolkit

Drugs used by today’s doctors can aid cells that are struggling, but they cannot replace cells that are lost. Cells in a failing heart, for example, can be made to beat more forcefully, but this typically leads to a more rapid decline of heart function as the cells falter and die. Therapies that allow the body’s natural stem cells to work have been the most successful.

Unfortunately, the body does not have enough stem cells to replace many vital cell types. Heart and brain cells that die in heart attacks and strokes are seldom replaced. Although fortunate patients do experience some recovery of function, this occurs because the surviving cells have taken on additional work and is always associated with a decline in functional reserve.

Replacing human cells in the heart and brain is not an impossible task. Remarkably, the hearts and nerves of some animals, such as certain fish and amphibians, grow back like new after they are damaged. The stem cells of mice, which are more closely related to humans, can be induced to become beating heart cells or neurons when they are provided the right environment in which to grow. It appears that human embryonic stem cells may do the same, although work in this area has been limited by federal funding guidelines.

Why don't human (or mouse) cells replenish damaged tissues in heart and brain disease? One possibility is that it simply wasn’t necessary—most early humans did not live long enough to suffer heart attacks, strokes, or neurodegenerative diseases. As humans live longer, perhaps we can rediscover the biological signals that will allow heart and nerve cells to regenerate.

Several small trials in Europe, Asia, and South America have begun to try to harvest stem cells from the bone marrow of heart attack patients, inject them into the heart, and induce them to beat. Although the trials are too small to prove a benefit of this therapy, it appears to be safe so far. In similar experiments, neuronal stem cells have been enriched and placed into the damaged brain region in Parkinson’s patients, with little if any real benefit. Although these early trials are interesting, many investigators believe too little is understood about long-term effects to be using stem cells in humans. Clearly, much more work needs to be done to ensure successful trials in the future.

Stem cell therapy presents many challenges. For example, the human body contains only relatively small numbers of stem cells. It is difficult to collect those stem cells from the body, grow them in large numbers, and then reintroduce them into the body. There are no alternative sources of sufficient stem cells. Stem cells from one person may be rejected when used in another person (analogous to rejection of a transplanted organ). Scientific understanding of the mechanisms that govern stem cell behavior is limited, and there are no medicines to control them.

Stem Cell Research at Gladstone

Embryonic stem cells develop into many other types of cells and provide a renewable source of potential replacement cells for many kinds of damaged tissues. Exciting progress has been made in controlling the behavior of stem cells. For example, Gladstone researchers have increased the efficiency of transforming stem cells to beating heart cells by over 100-fold in the last two years.

Unfortunately, the human body lacks a sufficient supply of stem cells to recover from many of today's most devastating diseases. Gladstone researchers are working on methods to reprogram stem cells to cure diseased tissues. Their hope is to find ways to entice more of the body's stem cells to replace lost cells or to physically engineer new tissues to supplement damaged tissue. Gladstone has been at the forefront of the scientific applications of stem cells—most notably the use of mouse embryonic stem cells to create genetically engineered mice. The ability to precisely modify genes in mice has greatly advanced the understanding of how genes work to prevent, and in some cases cause, disease. Gladstone has access to human embryonic stem cell lines that are currently approved for federal funding. In addition, we have active collaborations with UCSF researchers who are devising new embryonic stem cell lines that are more versatile and more appropriate for therapeutic use. As a private research organization, Gladstone has the flexibility to use private money to fund research on these new human cell lines that are not approved for federal funding. This work makes us well suited to apply for and win funding from the Institute for Regenerative Medicine (California's Proposition 71) in the future.

Over the next five years, with all of Gladstone working together in a single new facility, researchers will undertake a concerted effort to determine how stem cells replace diseased cells, how genes control this process, and how the process can be enhanced. The new Gladstone building includes a custom-designed embryonic stem cell laboratory complete with stem cell culture facilities, as well as space for detailed analysis of stem cell–derived tissues (beating heart cells, neural cells). This new laboratory will allow Gladstone researchers to rapidly develop new projects using stem cells and the latest techniques and equipment.

Gladstone's most valuable contributions to this field will likely be pre-clinical, entailing studies in model systems such as experimental animals. This work will provide the data needed to design the safest and most effective clinical trials of stem cell therapies. Gladstone is ideally suited to study stem cells in culture (outside of the body) and in mouse models. Our goals are to develop methods to generate therapeutically useful stem cells in large numbers and to isolate the genes within those cells that cause them to transform into heart and brain cells. The rewards for human health are potentially extraordinary.

Once the genes are isolated, drugs can be designed to enhance their function and to stimulate a patient's own natural stem cells. This strategy could eliminate the need to take cells outside of the body or to use cells from another person. These goals require expertise in areas that are particular strengths at Gladstone: growing cultured stem cells and isolating their genes.

As part of the BayGenomics project, Gladstone is a key partner in an international effort to modify all the genes in mouse stem cells. The initial focus of Gladstone research in this project will be on genes that regulate either the development or the beating of heart cells. Some of these genes may lead to new ways of growing heart cells or treating abnormal heart beats (cardiac arrhythmias). These are areas of critical concern because deaths from heart failure and cardiac arrhythmias continue to rise every year. Gladstone researchers have re-engineered over one quarter of all mouse genes in mouse embryonic stem cells and made these cells publicly available for research use. These cells are an invaluable resource for research in many important areas.

Dobutamine, an adrenaline-like drug, was added to embryonic stem cells that were induced to differentiate into beating cardiac cells. Adrenaline normally causes heart rate to increase in humans during times of stress. The cells respond as normal cardiac cells with increased beat rate. The beat rate is counted using a digital video camera attached to a microscope and a specialized software program.

Genetic engineering, which involves modifying genes to test their function, has become one of the most powerful tools in modern biology. It provides a means to understand the body’s own instruction manual. Each gene—humans have about 30,000—provides the cell with instructions on how to make a protein. Proteins are the machines that do the work inside cells.

The Human Genome Project essentially provided all the letters, in proper order, of the entire genetic instruction manual. Unfortunately, we don’t know what most of the “words” mean. To extend the analogy, genetic engineering is like changing a word and seeing what happens: if the result is an animal deficient in some function, then that gene directs that function. By engineering large numbers of genes in stem cells, Gladstone is creating a vast scientific resource for defining the critical components of stem cell behavior.

Beyond Mice

Although much progress has been made with mouse stem cells, Gladstone researchers are exhilarated by the prospect of extending their research to human stem cells. Unfortunately, the human cell lines that are approved for use in federally funded studies are resistant to the genetic engineering techniques commonly used in mouse stem cells. Thankfully, many new human stem cell lines are being developed in other countries or with private funding and soon, in California, with Proposition 71 funding. Gladstone researchers are hopeful that future research with human stem cells will reveal the secrets of how stem cells can be used to treat common human diseases, such as heart failure.

Cardiac myocytes derived from mouse embryonic stem cells. Bright green represents a gene-trapped cardiac-specific protein (SERCA), and red is a marker for skeletal and cardiac muscle (a-actin).		In September 2005, the California Institute for Regenerative Medicine (CIRM) awarded Gladstone $2.4 million to create a CIRM Scholars Training Program focusing on stem cell research. The training grant, part of CIRM’s first round of awards, will enable Gladstone to develop and implement an intensive stem cell-specific curriculum for 10 postdoctoral fellows over a three-year period. The CIRM is a state agency that was created by the California Stem Cell Research and Cures Act, a ballot measure passed by 59% of California voters in November 2004. Over the next 10 years, the CIRM will disburse almost $3 billion in state bond funds for
stem cell research to investigators at California universities and research institutions. Research funded by the CIRM will focus on understanding the fundamental mechanisms related to stem cells and how they apply to the development of disease. All proposals are peer-reviewed to identify the most promising science.