Stem cells are undifferentiated cells that can replace damaged cells through cell division. Sources of stem cells include adult, embryonic, induced pluripotent, and cancerous stem cells. Regenerative medicine uses stem cells to create living tissues to repair damage from aging, disease, injury, or defects by replacing lost tissues. This field holds promise for increasing healthy lifespans and offers advantages over organ transplants like avoiding immunosuppression and shorter recovery times. However, challenges remain such as ensuring stem cells integrate properly after transplantation and developing sufficient biomaterials for tissue engineering applications.

1. Stem cells and regenerative
medicines.
Stem cells are undifferentiated cells found throughout the
body after embryonic development that multiplies by cell
division to replace and regenerate damaged cells. The
sources of stem cell are – adult stem cells, embryonic SC,
iPS SC, cancer and leukaemia SC. This stem cell are used in
regenerative medicines for creating living, functional tissues
to repair and replace the tissues lost due to age, disease,
damage or congenital defects.
Regenerative medicine aids in people with longer healthy
living[1]. Most cells source for the embryonic stem cells are
the inner cell mass of an embryo and induced pluripotent
stem cells are produced by genetic reprogramming.
Regenerative medicine is a heterogeneous domain that
consists of multiple technological avenues in it.
Regenerative medicine has brought new hopes to the
medical industry. They are used in cell therapy and in tissue
engineering. One of the main benefit using stem cell therapy
is less usage of immunosuppression as the cells that are
damaged are replaced by the same patients cells.
why regenerative medicines?
•Organ rejection is a rarely faced issue in regenerative
medicine.
•Shorter recovery of victim.
•They can be banked at birth.
•There is no or less ethical controversy.
•Adult stem cells have limitless supply.
•Usage of own cells means no immunosuppression.
As said the wide range of studies that regenerative
medicine is based on are:
Cell therapy
When there are particular cells missing in a circuit , the stem
cell therapy helps in forming the sources of missing cells or
by manipulating the cell to produce the missing substances.
Some of the cells and their uses in stem cell therapy are
listed below:
Blood forming cells – blood and immune regeneration
Neural stem cells – for neurodegenerative cells[2]
Fibroblast cells – skin forming cells
Also used in treating autoimmune disease, spinal cord injury
and cancer by suppressing “do not eat me” signal.
Issues
Regenerative medicine can be an evolving solution for the survival
of human race but it have some limitations. In stem cell therapy
targeting the stem cell to its proper place is painstaking process and
needs more accuracy. After transplanting the cell they must
undergo proper integration with other cells. Tissue rejection is a
rare but a worst night mare in stem cell therapy. Coming to the
tissue engineering there is very low availability of biomaterials, and
they expand very less in in-vitro and also inadequate vascularity is
seen. Although scaffolds have many sources, there is a problem is
choosing the suitable scaffold and their control in spatial
differentiation in cells.
Saraswathi Rajakumar
School of biological sciences, Bangor university.
future
stem cell availability is very low which is a major issue in
cell therapy thus new methods to develop stem cells
must be encouraged. Biomaterial are adequate in
amount thus thhe various method of producing
biomaterials must be implemented. Further
investigations must be carried out on stem cell
Reference
1. Riazi, A. M., Kwon, S. Y., & Stanford, W. L. (2009). Stem cell sources for
regenerative medicine. In Stem Cells in Regenerative Medicine (pp. 55-90). Humana
Press.
2. Lindvall, O., Kokaia, Z., & Martinez-Serrano, A. (2004). Stem cell therapy for human
neurodegenerative disorders–how to make it work.
3. Park, I. H., Arora, N., Huo, H., Maherali, N., Ahfeldt, T., Shimamura, A., ... & Daley,
G. Q. (2008). Disease-specific induced pluripotent stem cells. cell,134(5), 877-886.
4. Kawamura, T., Suzuki, J., Wang, Y. V., Menendez, S., Morera, L. B., Raya, A., ... &
Belmonte, J. C. I. (2009). Linking the p53 tumour suppressor pathway to somatic cell
reprogramming. Nature, 460(7259), 1140-1144.
5. Lutolf, M. P., & Hubbell, J. A. (2005). Synthetic biomaterials as instructive
extracellular microenvironments for morphogenesis in tissue engineering.Nature
biotechnology, 23(1), 47-55.
6. Yang, S., Leong, K. F., Du, Z., & Chua, C. K. (2001). The design of scaffolds for use
in tissue engineering. Part I. Traditional factors. Tissue engineering, 7(6), 679-689.
Tissue engineering
The field where engineering and life science joins together
for the benefit of human health. Biological substituents are
used to restore the cells and tissues of human body that are
damaged. These biomaterials tend maintain and improve the
tissues and cells quality. Biomaterials were initially used in
implants but novel technologies have made it possible to use
biomaterials in cell therapy.
The biomaterial used for tissue engineering easily
reproducible, biocompatible and are non-immunogenic[6].
In the above figure :
a)Shows the isolation of inner cell mass from an
embryo at the stage of blastocyst. b) The pluripotent
stem cells are cultured in sutable media and
conditions. c) The cells then develop into the
specialized cell types. d) The cells are then
transplanted into the victim for treatment.
Cell reprogramming is a new technique through
which specialized cells can be induced with
pluripotency[3] and then reprogramed into specific
stem cells[4].
a)Cells to be reprogramed are treated with specific
growth factors. b) target cells are added with these
and are transfected. c) reprogramed cells are
harvested.
Synthetic and natural biomaterials both share
some advantages and disadvantages. Natural
biomaterials have low immunogenicity, interacts
well with host cell but the degradation rate cannot
be controlled. Whereas, in synthetic biomaterial
degradation rate can be controlled, they are
biocompatible and can be formed in complex
shapes.
a) Required cells are
taken by biopsy and
are cultured to form
a monolayer. b) the
cells are expanded.
c) the cells are
cultures on a 3D
scaffold. d) the cells
is then transplanted.
Scaffold is a porous,
absorbable synthetic or
natural polymer[6]. They help
in cell attachment and
migration, delivering and
retaining cells and biological
factors, and also diffusion of
nutrients and signals.
spray-on skin, limb
transplant, artificially
engineered valves, fingers
and genitals are
manufactured by
researchers. Recently, an
artificially engineered
windpipe was transplanted
successfully.