Introduction to Stem Cells and Regenerative Medicine

Abstract

Stem cells are a population of undifferentiated cells characterized by the ability to extensively proliferate (self-renewal), usually arise from a single cell (clonal), and differentiate into different types of cells and tissue (potent). There are several sources of stem cells with varying potencies. Pluripotent cells are embryonic stem cells derived from the inner cell mass of the embryo and induced pluripotent cells are formed following reprogramming of somatic cells. Pluripotent cells can differentiate into tissue from all 3 germ layers (endoderm, mesoderm, and ectoderm). Multipotent stem cells may differentiate into tissue derived from a single germ layer such as mesenchymal stem cells which form adipose tissue, bone, and cartilage. Tissue-resident stem cells are oligopotent since they can form terminally differentiated cells of a specific tissue. Stem cells can be used in cellular therapy to replace damaged cells or to regenerate organs. In addition, stem cells have expanded our understanding of development as well as the pathogenesis of disease. Disease-specific cell lines can also be propagated and used in drug development. Despite the significant advances in stem cell biology, issues such as ethical controversies with embryonic stem cells, tumor formation, and rejection limit their utility. However, many of these limitations are being bypassed and this could lead to major advances in the management of disease. This review is an introduction to the world of stem cells and discusses their definition, origin, and classification, as well as applications of these cells in regenerative medicine.

Ethics and Policy Issues for Stem Cell Research and Pulmonary Medicine

“…1 Since 1998, when embryonic stem cells were fi rst derived from human embryos, eff orts have focused on unlocking the potential of stem cells in a variety of diff erent applications, from disease modeling and drug discovery to tissue regeneration and stem cell-based therapies. 2 By combining stem cells with novel tissue engineering strategies and biomaterials, scientists are exploring the possibility that whole tissues and organs can be engineered for replacement of damaged or diseased ones.…”

Pluripotent stem cells and their use in hearing loss

“…Stem cells are grouped into five categories in terms of their plasticity capacity (Ilic and Polak, 2011;Kolios and Moodley, 2013): 1) Totipotent stem cells are undifferentiated stem cells of the earliest embryonic phase from zygote formation to the blastocyst phase. 2) Pluripotent stem cells are the embryoblasts from the inner cell mass on day 5 or 6 of the embryo.…”

“…2) Pluripotent stem cells are the embryoblasts from the inner cell mass on day 5 or 6 of the embryo. They can transform into all germ cells (except for placenta) with endo, meso or ectoderm character and form all tissues and organs; they have infinite proliferation capacity, are important for regenerative medicine, and are also known as ES cells (Kolios and Moodley, 2013 (Ilic and Polak, 2011;Kolios and Moodley, 2013).…”

Stem cell treatment for age-related neurodegenerative diseases

“…Stem cells are self-renewing,unspecialized cells capable of differentiating into any specialized cell type in the human body [1].Stem cells are important for embryonic development and organogenesis, but also for tissue homeostasis and regeneration in the post-natal and adult stages of life [2].Stem cells have three important characteristics: self-renewal, clonality and differentiation potential into multiple cellular lineages [3][4][5].…”