hESC mitochondrial transfer to empower withered cardiomyocytes

Funding Type: 
SEED Grant
Grant Number: 
RS1-00420
ICOC Funds Committed: 
$0
Disease Focus: 
Blood Disorders
Stem Cell Use: 
Embryonic Stem Cell
Public Abstract: 
Heart failure is the most important cardiovascular health problem worldwide. It is a common end result of multiple diseases such as hypertension, coronary artery disease, diabetes and obesity. In the United States alone, it afflicts 5 million patients and a substantially larger number of asymptomatic subjects have an evidence of left ventricular dysfunction. In addition, as discussed above, at least 60-70 million people suffer from diseases that render them susceptible to development of HF. The disease imposes an economic burden of more than 25 billion dollars every year. The clinical syndrome of heart failure is characterized by relentless progression of disease and in spite of significant medical advances the prognosis of advanced HF has not improved. Before this cardiovascular scourge evolves into an epidemic, we need to start a two-pronged strategy; identify predisposed early to prevent the progression of disease, and develop newer methodology to salvage the failing myocardium. Newer strategies for empowering failing myocardium include human embryonic stem cells (hESC) injections in the heart muscle so that these cells could proliferate to assume the characteristics of heart muscle cells. However, we propose that we should move away from the orthodox attempts of transforming hESC to heart muscle before they are seeded into the myocyte-deficient regions. Instead, we would focus primarily on revitalizing withered heart muscle cells. In heart failure, the inexorable decline of LV function, of many pathogenetic mechanisms, has been attributed to an interrupted suicidal process (called apoptosis). During this process, the power houses of the muscle (called mitochondria) are depleted of intermediates involved in energy production. Hence heart failure is considered energy-deficient state. We propose that revitalization of mitochondria is necessary to provide energy to failing heart muscle cells and that HESC can be used as the source of new mitochondria. Such mitochondrial transfer to failing cells may result in partial alleviation of heart failure. We propose that preparation of extra-nuclear part of human embryonic stem (hES) cells and its delivery to withered myocytes will replenish these cells. The hybrid cells thus will be formed in the heart muscle with new mitochondria from the stem cells.
Statement of Benefit to California: 
Heart failure is the most important cardiovascular health problem worldwide. Various cardiovascular diseases such as hypertension, coronary artery disease, diabetes and obesity, eventually lead to heart failure. Approximately 5 million patients suffer from heart failure in US alone and a substantially larger number of asymptomatic subjects have an evidence of left ventricular dysfunction. In addition, as discussed above, at least 60-70 million people suffer from diseases that render them susceptible to development of HF. The disease imposes an economic burden of more than 25 billion dollars every year. California has the lowest death adjusted death rate for heart failure compared to other states but yet carries one of the largest heart failure loads in the country (based on the ICD-9; 428.0-428.9). The clinical syndrome of heart failure is characterized by relentless progression of disease and in spite of significant medical advances the prognosis of advanced HF has not improved. We need to develop newer methodology to salvage the failing myocardium. Recently some revolutionary newer strategies have been proposed for empowering failing myocardium such as myocardial injection of human embryonic stem cells (hESC) so that these cells could proliferate to assume the characteristics of heart muscle cells. However, we propose that we should move away from the orthodox attempts of transforming hESC to heart muscle before they are seeded. Instead, we would focus primarily on revitalizing withered heart muscle cells, by mere mitochondrial transfer from the stem cells. California is the pioneering state that allows the jusdicious use of embryonic stem cells for research. This project promises not only the new hope for heart failure but may also allow a new paradigm in the management of various chronic degenerative diseases wherein energy production is limited. It is expected that if the proof of principle is demonstrated by the proposed experiment, such a technology would be immediately translated into the clinical experiment. Use of embryonic stem cells without the nucleus would preclude the potential devastating malignant transformations. Management of chronic debilitating diseases with virtually no side effects would result in quantitative and qualitative improvement in health. This should also offer an improvement in effective manpower within the state.
Progress Report: 
  • Our goal has been to improve the microenvironment where human embryonic stem cells (hESC) differentiate in order to generate functional hematopoietic stem/progenitor cells (HS/PC) in culture, with the ultimate goal to use these HS/PCs for the treatment of leukemias and other blood diseases. We have tested various human and mouse stroma lines for their ability to support expansion of multipotential human HS/PCs as well as hematopoietic specification from hESCs. So far mouse mesenchymal stem cells (MSC) have proven to provide the best supportive ability for human hematopoiesis. By combining embryoid body differentiation and co-culture on mouse MSC stroma, we have succesfully generated HS/PCs that phenotypically resemble bona fide human HSCs (CD34+CD38-CD90+CD45+). However, so far their differentiation ability has been biased toward myeloerythroid cells, with poor ability to generate B-cells in culture. Based on microarray data that we obtained from a related project supported by the CIRM New Faculty Award, we have identified molecular programs that are defective in hES derived HS/PCs. Future efforts will be directed in modifying the culture microenvironment as well as the cell intrinsic regulatory machinery in hES derived HS/PCs in order to improve their differentiation and self-renewal potential.
  • Our goal has been to improve the microenvironment where human embryonic stem cells (hESC) differentiate in order to generate functional hematopoietic stem/progenitor cells (HS/PC) in culture, with the ultimate goal to use these HS/PCs for the treatment of leukemias and other blood diseases. We have optimized a two step differentiation protocol that combines embryoid body differentiation and subsequent stroma co-culture to generate HS/PCs that exhibit the same phenotype as HSCs obtained from human hematopoietic tissues (CD34+CD38-CD90+CD45+). However, our findings indicate that the hESC derived HS/PCs have restricted developmental potential as compared to fetal liver or cord blood derived HS/PCs, and they senesce prematurely in culture, and are unable to generate B-cells . Our functional and molecular studies suggest that hES-derived HS/PCs resemble closely lineage-restricted progenitors found early in development in human hematopoietic tissues. Our recent studies have focused on exploring the possibility that another precursor that develops in the embryoid bodies could have lymphoid potential when placed in an appropriate microenvironment. Our preliminary data suggests that development of T-lymphocytes from hESCs in vitro may be feasible. Our future work will continue to focus on generating fully functional HSCs by improving the in vitro microenvironment where HS/PCs develop, and/or programming HSC transcriptional program using inducible lentiviral vectors.

© 2013 California Institute for Regenerative Medicine