New Faculty I
Arthritis is the result of degeneration of cartilage (the tissue lining the joints) and leads to pain and limitation of function. Arthritis and other rheumatic diseases are among the most common of all health conditions and are the number one cause of disability in the United States. The annual economic impact of arthritis in the U.S. is estimated at over $65 billion, representing more than 2% of the gross domestic product. The prevalence of arthritic conditions is also expected to increase as the population increases and ages in the coming decades. Current treatment options for osteoarthritis include pain relief and joint replacement surgery. Stem cells have tremendous potential for treating disease and replacing or regenerating the diseased tissue. This grant proposal will be valuable in weighing options for using stems cells in arthritis. It is very important to know the effect of aging on stems cells and how stem cell replacement might effectively treat the causes of osteoarthritis . In Aim 1 we will find out if stem cells can improve the function of the cells in diseased cartilage. In Aim 2 we will find out if injured cartilage can harm and kill stem cells. In Aim 3 we will find out if arthritic cartilage can signal stem cells to migrate into the diseased tissue and start repairing the tissue. In Aim 4 we will test whether stem cells can improve the healing of cartilage after surgery. Stem cells fight disease and repair tissues in the body. If this is true we anticipate that stem cells implanted in arthritic cartilage may also treat the arthritis in addition to producing tissue to heal the defect in the cartilage. An approach that heals cartilage defects as well as treats the underlying arthritis would be very valuable. If our research is successful this could lead to new ways to treat cartilage with or without stem cells. Treating cartilage degeneration would have a positive impact on the large numbers of patients who suffer from arthritis as well as in reducing the economic burden created by arthritis.
Statement of Benefit to California:
California has been at the forefront of biomedical research for more than 40 years and is internationally recognized as the biotechnology capital of the world. The recent debate over the moral and ethical issues of stem cell research have slowed the progress of scientific discoveries in this field especially in the US. The CIRM is a unique institute that fosters ethical stem cell research in California. The CIRM also serves as an exemplary model for similar programs in other states and countries. This grant proposal falls under the mission statement of the CIRM of funding innovative and untested research. The proposal will generate preliminary yet novel results in the treatment of cartilage degeneration and osteoarthritis and explore the potential use of tissue engineered products from stem cells. At a minimum new insights in the role of stem cell as anti-arthritic agents will be gained. If successful, this will further validate the significance of the CIRM program and help maintain California's leading position at the cutting edge of biomedical research.
SYNOPSIS: The proposal explores the use of human stem cells for repair of articular cartilage in the treatment of osteoarthritis. The PI proposes to investigate whether human embryonic stem cells (hESC) or mesenchymal stem cells (MSC) have an anti-arthritic effect on human chondrocytes in vitro and whether they have roles for enhancing matrix synthesis and assembly, promoting cartilage healing, function and density. Effects of disease state and age will also be assessed. There are 4 aims to this project. In the first aim, human articular cartilage will be cultured either in conditioned media from hESC grown on fibroblast feeders, feeders themselves, embryonic or bone marrow-derived MSCs and normal human chondrocytes, or in Transwell cocultures with the same cells. The anabolic effects will be monitored by analyzing the expression of a series of arthritic markers, the expression of cytokines (particularly IL-1 and IL-1 receptor antagonist), and matrix synthesis. The hypothesis is that stem cells modulate chondrocyte function in osteoarthritis by inhibiting IL-1. The second aim is to test if injured cartilage releases a soluble factor inducing apoptosis of the stem cells; such a finding would limit the potential therapeutic efficacy of these cells. The third aim is to test if stem cell migration and differentiation are dependent on the disease state of the cartilage - that is, if osteoarthritic cartilage would secrete promigratory soluble factors, such as matrix metalloproteinases. The fourth aim is to test, using an osteochondral model from human knee cartilage, whether stem cells promote healing by enhancing extracellular matrix synthesis and assembly. STRENGTHS AND WEAKNESSES OF THE RESEARCH PLAN: The strengths of this proposal are the expertise of Dr. D’Lima and his collaborators (Dr. Snyder for ESC, Dr. Lotz for chondrocytes) and the great need for repairing cartilage due to disease or trauma. Also, the utilization of multiple in vitro models of disease is innovative and significant. Four different and complementary hypotheses are postulated to explore the roles of hESC and hMSC in cartilage healing and osteoarthritis. Each hypothesis is tested in a set of studies that constitute one specific aim. Studies of Aim 1 are conducted first, and are followed by studies of Aims 2, 3 and 4 that are conducted in parallel. There is no unifying hypothesis, and it is not explained how the obtained data will be integrated, interpreted and utilized. Thus, the proposal appears disjoint with four rather independent and open-ended aims. Also, the proposal suffers from lack of detail on research design and methods. In each set of studies, the PI plans to use a panel of cells, comprising hESC grown on fibroblastic feeder cells, embryonic derived MSC, bone marrow derived MSC, and human articular chondrocytes. It is totally unclear how these cells are going to be derived. In particular, derivation of hMSC from hESC is still an unresolved problem. For other cells, standard protocols exist, but these need to be specified. Sources of the healthy and osteoarthritic cartilage that will be used are also not specified, beyond the statement that the former will come from tissue banks and the latter from patients. Why has no IRB approval (even as anonymous tissue for expedited review) been applied for since there are embryonic and bone marrow derived MSC as well as “fresh knee blocks for normal and aging chondrocytes, and chondral and osteochondral tissue samples” being used throughout? Why was the question on Stem Cell Research Oversight answered “No” when hESC (H-9 as well as possibly others) are being used? Preliminary studies establish the rationale for some of the proposed studies. For example, co-culture of ESC with osteoarthritic cartilage increased the rate of matrix synthesis in low-grade osteoarthritic tissue but not in normal cartilage tissue. Also, co-culture with osteoarthritic cartilage activated stem cell apoptosis. However, these studies do not give a direction for data synthesis and do not suggest how the obtained results could possibly be used. Furthermore, there is concern whether the experiments will give clear answers. It will be difficult to distinguish the effect from the added stem cells and the potentially endogenous stem cells (perichondrial?) that have been reported by the collaborator Dr. Lotz as being about 4% of human articular cartilage cells. The budget is unusual in that it includes substantial facilities costs (~$120,000 per year). QUALIFICATIONS AND POTENTIAL OF THE PRINCIPAL INVESTIGATOR: Dr. D’Lima was trained in medicine and orthopaedic surgery in Bombay, India, received his medical degree 25 years ago, and became a Research fellow at Scripps in 1994. By 1996, he was Head of the Joint Mechanics laboratory there and then in 2001, he became Director of the Orthopaedic Research Labs. In 2005 he was appointed Assistant Professor. He received a PhD in Bioengineering from UC San Diego in 2007. He has published a number of papers in speciality journals, some on chondrocyte biology and others on the biophysics of joint load and force. Several of these previous studies won awards. He has completed a NIH R21 on design of a tibial prothesis and has a pending R21 on “A whole joint cartilage testing device”. His career development plan is less well developed than others but he has a unique combination of expertise in chondrocyte biology and bioengineering. The career development plan builds on his previous work and is focused on activities that will result in the status of an independent investigator. The collaboration on hESC with Dr. Snyder and on MSC with a postdoctoral fellow working at the Burnham is a promising sign of expanding his expertise into stem cells. INSTITUTIONAL COMMITMENT TO PRINCIPAL INVESTIGATOR: Dr. D’Lima is considered an integral part of the Musculoskeletal Diseases Subgroup at the Scripps Clinic and Scripps Translational Science Institute. He has been the Director of the Orthopaedic Research Labs and directed the basic science research there since 2001 but has only recently, in 2005, been appointed as Assistant Professor (tenure-track). Dr. D’Lima indicated that Dr. Colwell, the chair of his department, “recommended full faculty appointment pending my first independent successful grant award”. Thus, it is not clear that there is strong commitment for Dr. D’Lima’s independence. The institution has a good track record in supporting their faculty. DISCUSSION: Although the reviewers agreed that the applicant is a qualified orthopaedist with expertise in chondrocyte biology, and that he is targeting an important problem in medicine, i.e. cartilage repair, they expressed concern about his proposal in several areas. The research plan lacks detail, is disjointed, does not provide a clear rationale for the proposed co-culture experiments or a description as to how the collected information will be integrated. This left the reviewers uncertain whether the proposed experiments will yield useful information. It is also unclear whether the PI will be able to procure the fresh human tissues he proposes to utilize in some of his studies. Although he only recently earned a PhD and was appointed Assistant Professor, the applicant earned his Medical degree 25 years ago, and has been Director of Research for many years, thus he has apparently reached a more advanced career stage than intended for funding under this RFA. Furthermore, the career development plan is not well worked out, no clear mentoring strategies or review criteria are presented, and the level of institutional commitment was considered marginal.