Cardiovascular Stem Cell Biology and Therapy

Introduction:

Cardiovascular disease is increasing globally despite many medical advances, with ischemic heart disease (reduced blood supply to the heart and great vessels) being the leading cause of death worldwide. Extensive efforts continue to improve effective therapeutic modalities that improve the patient's quality of life and survival. Novel therapies are being investigated to protect the heart against injury and regenerate the heart. Stem cell therapy can potentially use human mesenchymal stem cells, induced pluripotent stem cells (cells that produce well-differentiated functional mature cells) that can address molecular mechanisms of cardiac conditioning and develop new therapies for ischemic heart disease.

What Is a Stem Cell?

A cell that can continuously divide and differentiate into various other kinds of cells or tissues. Stem cells are undifferentiated immature biological cells that can differentiate into specialized cells and divide to produce more stem cells. The stem cells can self-generate and mature into well-differentiated functional cells. Stem cells have the capability of self-regeneration and differentiation. Stem cells are cells capable of self-renewal and differentiation. These cells or precursors can give rise to multiple tissue types, such as skin, muscle, or nerve cells. The stem cell divides, and the new cell can remain a stem cell or become another type with more specialized functions, such as brain and red blood cells. The stem cells are classified as:

• Pluripotent Cells - They can differentiate into almost all types of cells; for example, the cells are derived from mesoderm, endoderm, and ectoderm. They can form any type of cell, like blood cells.

• Totipotent Cells - They can differentiate into any other type of cell. They are embryonic stem cells that generate a new organism, for example, embryonic stem cells.

• Multipotent - They can differentiate into a closely related family of cells. For example, hematopoietic stem cells (cells of the blood).

• Oligopotent - They can differentiate into a few different cell types. Example includes lymphoid and myeloid stem cells of the reticuloendothelial system.

• Unipotent Stem Cells - They can produce only their types of cells. For example, muscle stem cells.

What Are the Types of Stem Cells?

The following are the types of stem cells:

• Embryonic Stem Cells - These stem cells come from embryos 3 to 5 days old. The pluripotent stem cells can divide into more stem cells and become any cell in the body. This versatility allows embryonic stem cells to regenerate or repair diseased tissue and organs.

• Adult Stem Cells - The stem cells are in small numbers in the adult tissues. The adult tissues include bone marrow and fat. The embryonic stem cells, adult stem cells have limited ability to give rise to various body cells. Researchers thought adult stem cells could create similar types of cells. The stem cells in the bone marrow give rise only to the blood cells. Some evidence suggests that adult stem cells may create various types of cells. The bone marrow stem cells can form bone and heart muscle cells (cardiomyocytes). Various research studies test adult stem cells in people with neurological or heart disease.

• Adult Cells Are Altered to Have the Properties of Embryonic Stem Cells - Normal adult cells are converted into stem cells using genetic reprogramming. Altering the genes in the adult cells can reprogram the cells to be similar to embryonic stem cells. This new technique allows the reprogrammed cells that prevent rejection of the new stem cells. There is no proven evidence that altered cells can cause adverse effects. In research studies, it can take normal connective tissue cells and reprogram them to become functional heart cells. In some studies, animals with heart failure injected with new heart cells experienced improved heart function and survival time.

• Perinatal Stem Cells - Researchers have discovered stem cells in amniotic fluid and umbilical cord blood. The stem cells can change into specialized cells. The fetal blood is a good source of hemopoietic stem cells that rapidly proliferate into functional cells. It is taken from the fetal blood, bone marrow, liver, and kidney.

What Are Human-Induced Pluripotent Stem Cells?

Human induced pluripotent stem cells are:

• Human embryonic and induced pluripotent stem cells can potentially transform the treatment of human cardiovascular diseases.

• It allows the designing of human cardiomyocytes (heart cells) based on drug discovery and predictive toxicology.

• Additionally, they represent an unlimited source of human heart cells for cell-based therapies to treat patients with severe heart disease.

• The initial heart pluripotent stem cell differentiation protocols yield a mixed population of immature cardiomyocytes (heart cells) composed of ventricular, atrial, and pacemaker cell-based therapies to repair damaged heart cells.

• The development of biological pacemakers will require access to specific populations of cardiomyocytes. Lineage tracing and gene targeting studies have provided important insights into the origin of different heart regions and showed that many derive from distinct progenitor populations specified early in development.

• Human pluripotent stem cells (hPSCs), which include human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), can self-renew indefinitely in culture while maintaining the ability to become almost any cell type in the human body. Human cardiomyocytes can be cultured for a long time and are available in sufficient quantity.

• HiPSCs derived from diseased patients may be able to provide new forms of treatment for ischemic heart disease due to their potential for repairing damaged heart cells. Stem cells have a clinical impact by secreting multiple growth factors and cytokines.

• Trophic mediators secreted system cells improve cardiac function by combining various mechanisms, promoting the blood supply, new blood formation, and inhibiting fibrotic remodeling. Stem cells also secrete Extracellular components, including collagens, TGF-beta, matrix metalloproteinases, and tissue-derived inhibitors that inhibit fibrosis. The stem cells are bone narrowed-derived cells, myoblasts, endogenous cardiac stem cells, umbilical cord-derived mesenchymal stem cells, and embryonic stem cells. Fibroblasts are the most commonly used primary somatic cell type for generating HiPSCs. Fibroblasts can be reprogrammed to be stable HiPSCs.

Conclusion:

The existing therapies for ischemic heart disease have many limitations. Efforts are underway for new stem cell therapy treatments to improve clinical conditions by replacing damaged heart cells or improving cardiac performance with new functional cells. Cardiac tissue regeneration with stem cells and tissue engineering may be effective therapeutic options for ischaemic heart disease.