4LEARNING OUTCOMES
- Define what stem cells are
- Classify the different stem cell types
- Describe how stem cells can be used therapeutically
- Discuss current limitations for stem cell therapies
what are stem cells
are self-renewing and able to differentiate into all type of cells
what is the origin of stem cells
blastula which form human embryonic stem cells
what are the classification of stem cells
they are classified according to their ability to produce
-totipotent: stem cells that can produce a whole organism
-pluripotent: stem cells that can produce all 3 germ layers
-multipotent (mature stem cell): only produce tissue specific cell line.
what are the embryonic stem cells (ES) and their function
ES are isolated from the fertilized eggs.
f(x):
- give rise to all three germ layers, ES can be converted into the neurons, blood cells, and liver cells.
- in vitro study for development process which can’t be assessed otherwise.
- used in cell therapy for the transplant of cells of interest differentiated from ES cells into patients
what are the ES cells limitation
- allogeneic transplant can lead to immune rejection due to unmatched human leukocytes antigen
- ethical concern about the human blastocysts
how to solve the immune rejection of ES cells
-bio-banking: which is the production of an ES cell bank with ES cell line derived from HLA that are commonly found in population
- production ES cells from patients themselves
-somatic cell nuclear transfer
how does somatic cell nuclear transfer done
- isolate nucleus of patient’s cells and inject it into an unfertilized egg
- then development of cloned embryo, ehich have the same antigen haplotype and can be used to isolate ES cells
can mature somatic cells programmed to become pluripotent stem cell
yes
what is the problem with therapeutic cloning
insufficient source of embryo oocytes because there is need of more than one egg per patient to have successful injection of nucleus
how can we solve the above problem of embryo oocyte source
we can use pluripotent stem cells (IPS cells).
means now we can do stem cell therapy based on the IPS cells
how does IPS cells formed
fully differentiated somatic cells can be programmed to pluripotent stem cells with introduction of special pluripotent genes via viral transduction
what is IPS cell and their potential
- all the f(x) of stem cells including: transplant, give rise to all three germ layers, in vitro study of development
- no ethical issue because no need for the embryos
- are vastly renewable, cell number is not a limitation
- easy accessible/ less expensive
-non-immunogenic
what are the cons of IPS
- problem of transplanting incomplete differentiated cells
-personal medication is not possible means is time consuming and not patient friendly
-tumorigenicity
what are Multipotent stem cells
adult stem cells that are tissue specific or that only produce specific cell line
what is the cons of multipotent stem cells
they are hard to isolate and access
what are Hematopoietic stem cells (HSCS)
are blood stem cells that are in process of producing blood cells
which cell that are mostly used during stem cells transplant
HSCS
- describe allogeneic HSC transplantation ad give the diseases
- stem cells are collected from donor
- stem cells are infusion into patient without immune system: here first destroy the patient leukemia cells and immune system
- rebuild of immune system with donor cell, give patient with new hematopoietic system
diseases: leukemia
what are Mesenchymal stem cells (MSCS)
they can differentiate into the osteocytes, chondrocytes and adipocytes
what are the pros of MSCS
- immunosuppression property
- short-term existence means is allogeneic safe
- anti-inflammation properties
What do we need to consider when taking a stem cell therapy to the clinic?
- scarcity of stem cells: know the source,HSC ex-vivo
- design protocol to obtain cell of interest from stem cells: ensure complete differentiation of all pluripotent stem cells, make sure the cell of interest are obtainedblood formation during development
- safety of material to be transplanted
- how to efficiently deliver the cells: transdifferentiation, bioengineering
Pluripotent stem cells can give rise to neural stem cells.
yes
ESCs and iPSCs are equivalent for
transplantations as part of stem cell
therapies.
no, because they can lead to ethical problem, tumorigenicity, immunogenicity
