Induced Pluripotent Stem Cells (Ipscs)

Stem cells are tiny little balls of cells which are undifferentiated cells that can separate into particular cell sorts. Scientists and researchers focus on two main types of stem cells; Adult stem cells which come from the brain, spinal cord and most parts of the body and embryonic stem cells which are cells that are extracted from embryos. Researching on stem cells show that they could potentially save millions of lives by enabling scientists to develop ways to treat and cure some of the most degenerative conditions. So why not use them?

What is a stem cell? A stem cell is an unspecialized cell, meaning it is not a heart, brain, or any other type of cell that has a special purpose,

Originally in Takahashi and Yamanaka’s experiment, retroviruses were used as a vector to introduce factors that triggers reprogramming, however with evidences from further researches shown that retroviruses may cause insertional mutagenesis, where the host’s DNA is mutated due to the virus integrating into the host’s genome, and potentially cancerous nature of the iPSCs made this technique ill suited to further iPSC developments.(5) Therefore, other methods have been developed and used nowadays to minimise these issues and they include protein transduction, the use of

is a stem cell? Well basically they are cells in the human body that exist in a sort of neutral

Embryonic stem cells are found in human blastocysts (Marcovitz 17). A blastocyst is a very young embryo (just a few days old) that contains around 200 undifferentiated stem cells (Marcovitz 17). German Zoologist Valentin Hacker coined the term “stem cell” after he discovered them in a blastocyst of a crustacean (Marcovitz 18). Embryonic stem cells were collected for the first time in 1988 by Dr. James Thomson of University of Wisconsin and by Dr. John Gearheart of Johns Hopkins (Panno 76). These stem cells are unspecialized; they do not perform a specific function like cells such as muscle and nerve do (“Stem Cells”). They are also pluripotent, meaning they have the ability to divide and become specialized cells (“Stem Cells”). This is why stem cells hold so

Stem cells are a type of cell that basically always divide in order to replace other cells in the body. They are different from normal cells because once they have first divided into a new stem cell, they can become another type of cell, such as a muscle cell or blood cell, tissue, or they can continue being a stem cell. They also can remain inactive for a period of time, yet they can still divide into new cells whenever they are needed.

Embryonic stem cells (ESCs) are grown in the laboratory from cells found in the early embryo. ESCs have an unlimited chance to

Stem cells are unspecialized cells, which have the potential to develop into several different cell types—muscle cells, brain cells, skin cells, or red blood cells—during early development. Stem cells continuously divide in order to replace other cells. As stem cells divide, they have the potential to develop into a specialized cell or remain a stem cell. Induced pluripotent stem cells (iPSCs) play an essential role in tissue regeneration, and can circumvent immune system concerns. There are a variety of stem cells, including embryonic stem cells, adult stem cells, and induced pluripotent stem cells. However, the main focus of this paper will be the usage of induced pluripotent stem cells.

The iPSC’s were different from the host cells because a piggyBac vector was introduced into the hiPSC. A piggyBac vector is a genetic element that literally does what it sounds like, gives a piggyback between vectors and chromosomes, and cuts genes, carries them, and pastes them into a new position. This specific piggyBac vector used to distinguish the host cells from the iPSC’s stably expressed GFP (green fluorescent protein) gene under a ubiquitous promoter. The promoter was EF1 (elongation factor used to push gene expression in vitro and in vivo). The authors knew their transplantations of iPSC’s were successful because once the cells were introduced they observed continuous GFP fluorescence. The GFP fluorescence was observed even after differentiation of neural-linage.

Figure 2. Schematic illustration of generating Nf1-/- iPS cells from its Nf1+/- counterparts. (A) is the genotype of Nf1+/- iPS cells. (B) and (C) are two kinds of Nf1-/- iPS cells after Crispr/cas9 mediated NF1 genome editing in Nf1+/- iPS cells. In the presence of the repair template, Crispr/cas9 is able to introduce a nonsense mutation (c.94-96>TAA) into the exon 2 of NF1 genome via the homology directed repair (HDR). Without the repair template, random insertions and/or deletions may be introduced by non-homologous end joining (NHEJ). Nf1-/- iPS cells are to be generated by introducing

During the earliest stages of the development of the embryo, its cells are entirely undifferentiated. When a cell has not yet discovered its operation in an organism, it is classified as a stem cell. The two major varieties of stem cells have been distinguished as pluripotent and totipotent. An example of a totipotent cell is an egg that has been fertilized by a sperm cell, and is a single cell egg. This cell now has the ability to develop into any and every human cell. “The first few cell divisions in embryonic development produce more totipotent cells. After four days of embryonic cell division, the cells begin to specialize into pluripotent stem cells” (Biomed Brown Edu). Pluripotent cells however, are not as adaptable. Nicknamed the “master cell”, pluripotent cells have the ability to produce cells from the three basic body layers, enabling the possibility for them to create all cells or tissues that the body may need to heal (Children’s Hospital Organisation).

Stem cells play a fundamental role during all stages of development and have the potential to study and treat disease (Spitalieri et al., 2016). Embryonic stem cells (ESC) are pluripotent cells that emerge from the inner cell mass of the blastocyst and can give rise to various cell types (Liang and Zhang, 2013). Induced pluripotent stem cells (iPSC) have similar characteristics but are derived from adult differentiated somatic tissue (Liang and Zhang, 2013). This review will briefly compare ESC and iPSC in the context of cell therapy and disease modeling.

iPSCs are adult stem cells that have been genetically reprogrammed to behave like the pluripotent stem cells found in embryos, i.e. can differentiate into any cell type in the human body. This was first completed successfully in mice in 2006 by Shinya Yamanaka and his team (Takahashi et al., 2006), then in humans in 2007 both by Yamanaka (Takahashi et al., 2007), and by James Thomson and his team in America independently (Yu, et al., 2007). Yamanaka and Thomson’s methods were similar. In the report by Yu et

Research on stem cells has indicated new possible therapies and treatment for people with conditions that were once considered terminal. Parkinson’s disease, Alzheimer 's disease, and multiple sclerosis are a few of the many diseases that stem cells might be able to treat. Stem cells have the capability to repair heart muscle and neural tissues, improving the overall prognosis of the patient. For example, hematopoietic stem cell transplantation and mesenchymal stem cell therapy have shown promising results in clinical trials in reducing the effects of multiple sclerosis (Holloman, Ho, Hukki, Huntley, & Gallicano, 2013). Although stem cells show potential in their capability to treat diseases, the cells are delicate, limiting the success of research and clinical trials. Meanwhile, stem cells need to be differentiated from the other tissues of the body, presenting a challenge of marking the cell while also maintaining their viability. Several imaging technologies are being utilized to progress stem cell therapies. Such modalities include “positron emission tomography (PET), computed tomography (CT), single photon emission CT (SPECT), ultrasound (US), bioluminescence imaging (BLI), fluorescence imaging (FLI), [and] magnetic resonance imaging (MRI),”(Cho, Wang, Mao, & Chan, 2016) while “MRI and PET are the most widely investigated and developed”(Cho et al., 2016). Each imaging modality has their own advantages and disadvantages for delivering and tracking stem cells. Tracking

Stem cells are cells that have the capabilities to develop into many different types of cells in the body. Serving as a type of repair system for the body, they can theoretically divide without limit to take over for other cells for