What Happens When The Body Receives Stem Cells?
What are the stem cells?
Stem cells are a special type of cells capable of making their copies and converting them into any cell type. The conversion or differentiation of stem cells is according to the body's needs. There are different kinds and sources of stem cells found in different body parts at different intervals.
Stem cells are the body's raw materials that can generate different structures and particular functions. Under favorable body conditions, stem cells divide into daughter cells to perform their functions.
What happens when the body receives stem cells?
The different types of transplants through which stem cells work in the body are:
Autologous transplant – in this type of transplant, you receive the stem cells from your body cells. At first, with different medications, your stem cell count is enhanced and then taken out.
After taking out the autologous stem cells, these stem cells are processed and then injected into the patient’s body. In the pre-transplant phase, your body is prepared for collecting or receiving the stem cells with high chemotherapy dose (in case of cancer). In the final phase, the stem cells are kept back in the body through the infusion into the bloodstream via a catheter.
Allogenic transplant – in this transplant type, a matched donor is necessary to carry out the process. After selecting a suitable donor, the stem cells are extracted and processed into the patient’s body. Similarly, after processing, these stem cells are injected into the bloodstream of the patients to enhance the saturation and count of stem cells in the body.
Why are stem cells necessary?
Stem cells can make blood cells, skeletal cells, smooth muscle cells, and neurons. For doing these jobs, your body needs to have enough concentration of hematopoietic cells. Hematopoietic stem cells are those cells that start immature (young) and develop into red blood cells, white blood cells, and platelets.
Other than the hematopoietic cells, mesenchymal stem cells can easily migrate to the injured sites and differentiate into any type of end-stage functional cells. This process of migration and differentiation repairs the injured tissues in the body. More specifically, MSCs can successfully modulate the immune cells from both adaptive and innate immune systems. MSCs can efficiently promote angiogenesis, cause neovascularization, and improve the proliferation of other cells. Moreover, these cells can inhibit cell death and modulate immunity responses through cell-cell and paracrine contact effects through the extracellular vesicles.
The mechanism of action of stem cells depends upon a few different factors which determine the functioning of the cells as:
• Mode of transplant
• Source and requirements of the transplant
• Soluble factors
• Angiogenic factors
• Anti-apoptotic factors
• Antioxidative factors
• Cell to cell contact in the body
• Mitochondrial transfer
• Exosomes (extracellular vesicles)
For instance, a stem cell enters the body, and it has three options to migrate to its place through cell-cell contact, mitochondrial transfer, or through the exosomes. In the case of cell-cell contact, mesenchymal stem cells need to induce the Treg cells for maintaining self-tolerance and hemostasis. Different contact depending factors tend to affect the biology of the neighboring responder cells and body tissues. Therefore, special care is needed for these cells to optimize the strategies for inducing the stem cells successfully.
In the case of mitochondrial transfer, mitochondria play vital roles in ATP generation, cellular apoptosis, and oxidative phosphorylation regulation. Mitochondria provide the basic energy required by the cells to grow and move around the body cells. A dysfunctional mitochondrion can cause an increase in the production of ROS (reactive oxygen species) to cause oxidative damage to the cells. In case of a successful induction or transplant, mitochondria provide the cells with enough energy to proceed with their proliferation and destruction of the harmful cells. According to the research studies, a mitochondrial transfer can occur via gap junctions, isolated mitochondria transfer, cell fusion, TNTs, and microvesicles. Mitochondrial transfer is best for the protective effects in case of SCI (spinal cord injury), neurotoxicity, ischemic damage, burn of epithelial cells, renal or kidney injury, and lungs injury (bronchial epithelial injury).
Extracellular vesicles or exosomes are the membrane-bounded vesicles released by the somatic cells for tissue repair, proliferation, and immunomodulation. Extracellular vesicles have further classifications into apoptotic bodies, microvesicles, and endosome-derived plasma membrane-coated vesicles (30-150 nm in size). EVs have extraordinary properties for regeneration, anti-tumor procedures, and immunomodulatory functions. EVs enhance the process of angiogenesis. Angiogenesis is the formation of new blood capillaries to nourish the newly formed cells. Owing to EVs’ proliferative and angiogenic function, they can enhance the body's specific transcript and protein contents. In MSCs, the protein content mediates angiogenesis through the NF-κB signaling pathway regulations. Moreover, these exosomes also enhance muscle regeneration through myogenesis.
Takeaway:
Stem cell-based therapies are based on the interaction with their target cells in the body. After injection into the body, these cells modulate the immunomodulatory effects by suppressing proliferation and T-cell activity, regulating macrophages, and promoting regulatory T cells (Treg cells). A successful therapy accounts for different factors which altogether play a vital role in the success of the treatment.
References:
• https://www.futuremedicine.com/doi/abs/10.2217/rme-2017-0056 •https://scholar.archive.org/work/hkcfa4txfbcithbyxyuc3nlabe/access/wayback/
