Overview on Adult stem cells

Introduction

Adult stem cells are undifferentiated cells found in tissues and organs among differentiated cells. They may self-renew and differentiate into distinct cell types. Adult stem cells, unlike ESCs, can only differentiate into specific cell types of their tissue of origin, making them multipotent or unipotent stem cells. Adult stem cells are uncommon and often tiny in quantity, although they can be discovered in a variety of adult organs. Adult stem cells are a diversified stem cell population present in a variety of adult organs, including the blood, bone marrow, brain, skin, fat, lung, gut, and urethra.



History of stem cells

The term stem cell was coined by two zoologists, Theodor Heinrich Boveri (1862-1915) and Valentin Häcker (1864-1927), to designate cells devoted to giving birth to the germline. With the blastomere hypothesis of teratoma-like tumors, boveri aimed to explain Julius Cohnheim's notion of embryonic nature tumor etiology and pathogenesis, as did Max Askanazy (1865-1940), Felix Marchand (1846-1928), and Robert Bonnet (1851-1921). Franz Ernst Christian Neumann, a histologist who studied bone marrow, and Alexander Alexandrowitsch Maximow (1874-1928), both argue that all adult blood cells are produced from a single cell progenitor. Maximow came up with the notion of poly blasts while working on this project. Ernst Haeckel would later coin the term "stem cells'' to describe these cells that have the ability to regenerate and differentiate (1834-1919). He starts with the Mendelian notion, which he believes can't always explain heredity and phenotypic features, so he develops a new study concept he'll term phylogenetics. He then went through the fundamentals of hematopoiesis theory. Ernest Armstrong McCulloch (1926-2011), a biophysicist, and James Edgar Till, a cell biologist, were pioneers in using the quantitative clonal approach to examine stem cells in the early 1960s.

Sir Martin John Evans (born 1941) and Matthew Kaufman (1942-2013), two scientists, grew mouse embryonic stem cells for the first time in the laboratory in 1981, and earned the Nobel Prize in physiology and medicine in 2007 alongside Mario Capecchi and Oliver Smithies.


Properties of adult stem cells
  • Adult stem cells have a variety of self-renewal characteristics, and they face the same challenges in culture as primary cell types.

  • While many adult stem cell populations, such as those found in the bone marrow and blood, have been thoroughly studied and have defined isolation, expansion, and differentiation techniques, adult stem cells from many other organs are still in their infancy.

  • Adult stem cells can be artificially reverted to a state where they behave like embryonic stem cells.

Types of adult stem cell
  • Hematopoietic stem cells

  • Mammary stem cells

  • Intestinal stem cells

  • Mesenchymal stem cell

  • Endothelial stem cells

  • Neural stem cells

  • Olfactory adult stem cells

  • Neural crest stem cells

  • Testicular cells


Clinical significance

The use of adult stem cells in research and therapy is not considered as controversial as the use of embryonic stem cells, because the production of adult stem cells does not require the destruction of an embryo. CD34+ hematopoietic stem cells are found in greater numbers in males than in women of reproductive age among spinal cord injury sufferers, according to research. Many scientists are interested in the therapeutic potential of adult stem cells, since they can be extracted from the mother's body after birth. During transdifferentiation, a differentiated stem cell from one lineage produces cells from another lineage. In some types of adult stem cells, transdifferentiation is more likely to occur than in others, but for many types, no such transformation is possible. Adult stem cell treatments necessitate a stem cell source of the desired lineage, and extracting and/or growing them in sufficient quantities is difficult.


Research on adult stem cell

Adult stem cell research dates back more than 60 years. Researchers found that bone marrow includes at least two types of stem cells in the 1950s. Those are hematopoietic cells and bone marrow cells. The researchers have found the adult stem cell in our body in many tissues, also they have found them in the brain and heart, the places that were least expected. Adult stem cells are the only form of stem cell that has demonstrated indications of effectiveness in treating patients, and treating people is ostensibly the ultimate objective of stem cell research, and definitely the basis for the massive sums of money spent into the subject. Adult stem cell research has progressed unevenly and more slowly than many had predicted. Adult stem cells are the gold standard of stem cells for patients due to their superiority in the clinic and accumulating data supporting their efficiency in regeneration and repair.


Conclusion

These cells appear to have a considerably larger cellular differentiation potential that is dependent on and responsive to particular stimuli present in the engrafted site's environment. Just like with embryonic stem cells, questions about scale-up and guided differentiation for transplantation and tissue repair remain unanswered, but their possibly autologous origin makes them exceedingly attractive in the development of cell replacement treatments. These cells appear to have a considerably larger cellular differentiation potential that is dependent on and responsive to particular stimuli present in the engrafted site's environment. Just like with embryonic stem cells, questions about scale-up and guided differentiation for transplantation and tissue repair remain unanswered, but their possibly autologous origin makes them exceedingly attractive in the development of cell replacement treatments.


- Supal Patel

Department of Biochemistry and Biotechnology

St. Xavier's College Ahmedabad


References
  1. Ioannis Alexandros Charitos, Andrea Ballini, Stefania Cantore, Mariarosaria Boccellino, Marina Di Domenico, Elisa Borsani, Riccardo Nocini, Michele Di Cosola, Luigi Santacroce, Lucrezia Bottalico, "Stem Cells: A Historical Review about Biological, Religious, and Ethical Issues", Stem Cells International, vol. 2021https://doi.org/10.1155/2021/9978837

  2. Hu, D.JK., Yun, J., Elstrott, J. et al. Non-canonical Wnt signaling promotes directed migration of intestinal stem cells to sites of injury. Nat Commun 12, 7150 (2021). https://doi.org/10.1038/s41467-021-27384-4

  3. Pritha Ray, Abhijit De, Shahriar Yaghoubi, Aparna Khanna. Stem Cells Int. 2015; 2015: 258313. Published online 2015 Aug 4. doi: 10.1155/2015/258313

  4. Stefania Montagnani, Maria A. Rueger, Toru Hosoda, Daria Nurzynska. Stem Cells Int. 2016; 2016: 7362879. Published online 2016 Feb 2. doi: 10.1155/2016/7362879

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