Stem Cell Research and Therapies: A Review

In recent years, study into stem cell therapy has become increasingly promising and advanced. Even the most technologically advanced nations suffer from morbidity and mortality due to issues with their key organs. With the scarcity of transplantable organs, there is increasing optimism that stem cells could be the answer to humanity's longing to be able to replace tissues destroyed by illness and aging. Indeed, it is hard to pick up a newspaper these days and not come across some new apparent "breakthrough" in stem cell research, with the most hopeful ones hoping to discover an elixir of life (1). Stem cells are human body cells that are not specialized. They possess self-renewal capabilities and can differentiate into any type of organism's cell. From the earliest phases of human development until the end of life, every one of us possesses stem cells. The stem cells, which are unspecialized cells, possess the capacity to differentiate into the specialized cells that make up the many tissues found in the human body.  Their ability to divide into a wide variety of specific cell types and replenish themselves through mitotic cell division is what distinguishes them (2). Adult cells and developing embryos both contain stem cells. There are multiple specialized stages. A unipotent stem cell can only differentiate into a small number of distinct types of cells compared to a pluripotent one since its developmental potency decreases with each stage (3). The ability to extract stem cells from a human embryo and demonstrate that these cells could be kept in the so-called pluripotent condition was achieved for the first time. Basically, one special quality of stem cells is their pluripotency, which allows them to divide endlessly into daughter cells while also having the ability to develop into any type of human cell when given the right stimulus (4). Since tissue regeneration and cellular replacement are at the forefront of regenerative medicine, several stem cell types, such as human pluripotent stem cells (HPSCS), have been employed to accomplish these goals. Progenitor cells and multipotent stem cells. Thus, this review offers a concise summary of stem cell-based therapy for the treatment of human diseases as regenerative medicine continues to advance and evolve and dispel the myth of the "magic" cells (5). Since stem cells were discovered and their special qualities became known, they have been characterized as therapeutic agents for the repair of organs and tissues. Because of their vast range of possible uses, stem cells are seen as promising prospects for regenerative medicine. Researchers that examine the potential uses of regenerative medicine in a variety of disorders, including degenerative diseases, are now considering it as an alternative to conventional drug-based treatments (6).

Stem Cell Classifications: They are separated into two categories: nonembryonic (sometimes referred to as adult stem cells) and embryonic. Five types of stem cells are identified based on differentiation potential: totipotent, pluripotent, multipotent, oligopotent, and uniceptent. totipotent stem cells has the ability to differentiate into both extraembryonic and embryonic cell types. While multipotent stem cells develop to produce any form of cell, primarily within a closely related cell family, pluripotent stem cells give rise to all endoderm, mesoderm, and ectoderm cell types. The differentiation potential of oligopotent and unipotent stem cells is limited to a single cell type and a few cell types, respectively (2,7).

• Totipotent: The capacity to differentiate into every kind of cell that exists.
  The zygote created during fertilization of eggs and the initial cells produced by zygote division are two examples.
• Pluripotent:  The capacity to develop into practically every sort of cell.
  Embryonic stem cells and cells originating from the mesoderm, endoderm, and ectoderm germ layers that emerge in the early phases of embryonic stem cell differentiation are two examples.
• Multipotent:  The capacity to separate into a closely related cell family. Hematopoietic (adult) stem cells are one example; these cells can develop into platelets or red and white blood cells.
• Oligopotent: Able to divide into a tiny number of distinct cells. Adult lymphoid or myeloid stem cells are two examples.

• Unipotent: the capacity to differentiate only between cells of their own kind while possessing the self-renewal quality necessary to be classified as stem cells. Muscle stem cells from adults are one example.

Fig.1 The blastocoel, which is created from oocytes, is made up of embryonic stem cells that can subsequently differentiate into mesodermal, ectodermal, or endodermal cells. Oocyte development and stem cell production. The gastrula is formed by blastocoel development.

Some guidelines for basic stem research:

1. Research that uses tissues or cells that are directly taken from human subjects must first receive approval from the IEC and IC-SCR.
2. Researchers must process and develop stem cells and cell lines in a CDSCO-certified GLP and GMP facility if they plan to use them in clinical trials.
3. Research on human embryos intended for implantation in vitro cannot be done on the embryos after 14 days of fertilization or until the primitive streak forms, whichever comes first. In a similar vein, no in vitro modified cells may be placed in an animal or human uterus with the goal of creating an entire organism.
4. We will not perform any in vitro studies on human embryos meant for preimplantation any longer than 14 days after fertilization or until a primitive streak forms, whichever occurs first. In a similar vein, no uterus—human or animal—should contain genetically altered cells meant to generate a whole organism. (11).

Preclinical Research and Clinical Trials:

In vitro research on human embryos intended for preimplantation will be conducted beyond 14 days of fertilization or the creation of a primitive streak, whichever comes first.Similarly, no human or animal uterus should include in vitro modified cells intended for the purpose of producing an entire organism (12). It entails creating a unique product that can be used at the bedside that is both safe and effective and is based on fundamental research. Preclinical tests in animal models are known to not always be able to predict human immune response and cell behaviour (10)

Clinical Trials: The discovery of novel, secure, and efficient drugs for the treatment of human disease is the ultimate aim of drug development. The part of this project involving human subjects are clinical trials. Preclinical research and scientific inquiry share the same fundamental principles. Providing an objective assessment of the benefits of utilizing one or more treatment options for a particular disease or condition of interest is the main goal of the majority of clinical studies (13).

Guidelines are given below;

1. Reagents: Where applicable, the quality control program should test the reagents and their constituent parts for potency, safety, and purity when employing research-grade material.
2. Trial Participants: The inclusion and exclusion criteria outlined in the duly authorized protocol will be adhered to in the selection of trial participants.
3. Information For Human Participants: The patient information sheet and informed consent form need to have prior approval from IC-SCR and IEC. They also need to specifically state.
4. Regulatory Approval: The necessary clearances from CDSCO, IEC, and IC SCR before participant enrollment in clinical trials are covered in this section.
5. Monitoring: For every clinical research, a distinct Data Safety Monitoring Board (DSMB) ought to be set up (14).

Therapeutic Uses of Stem Cells:

The potential of stem cells to differentiate into different types of cells within the body makes them highly promising for use in therapeutics. Utilizing stem cells for medicinal purposes involves:

• Regenerative Medicine:  Diabetes, Parkinson's disease, spinal cord injuries, heart disease, and other disorders may be treated with stem cells because they have the ability to rebuild damaged tissues and organs.
• Bone Marrow Transplantation: Bone marrow contains hematopoietic stem cells, which are used in transplants to treat blood diseases like lymphoma, leukaemia, and other immune system or genetic conditions.
• Gene Therapy: Before being transplanted into patients, stem cells can be genetically altered to address genetic flaws, providing possible therapies for genetic illnesses like muscular dystrophy and cystic fibrosis.
• Drug Testing and Development: Through the creation of disease models for drug testing, stem cells enable researchers to better understand the course of disease and design new treatments.
• Treatment of Neurological Disorders: In diseases including Alzheimer's, multiple sclerosis, and spinal cord injuries, stem cells may be able to repair damaged neurons and replace lost function.
• Autoimmune Diseases: It is being investigated whether stem cell transplantation, which resets the immune system, can treat autoimmune disorders such as Crohn's disease, lupus, and rheumatoid arthritis (14–16).

Fig.2 Possible Treatment by Stem Cells

Banking Of Biological Tissues as Sources of Stem Cells:

There are many benefits to storing biological tissues as sources of stem cells for use in research and medicine. The following are some important details about biological tissue banking for stem cells:

• Preservation of Stem Cells: Important stem cells can be found in tissues like tooth pulp, bone marrow, adipose tissue, and umbilical cord blood. By banking these tissues, it is possible to preserve the cells for use in upcoming medical treatments or research projects.
• Umbilical Cord Blood Banking: After delivery, umbilical cord blood is frequently stored because it contains a wealth of hematopoietic stem cells. Deficits in the immune system and blood diseases can be treated with these stem cells. For families who wish to store cord blood for possible future use, both public and private cord blood banks provide storage services.
• Adipose Tissue Banking: Mesenchymal stem cells (MSCs) found in adipose tissue, also referred to as fat, have the capacity to differentiate into a variety of cell types, such as bone, cartilage, and muscle cells. By storing adipose tissue, these MSCs can be separated and kept for use in tissue engineering and regenerative medicine.
• Bone Marrow Banking: Haematopoietic stem cells are found in bone marrow and are essential for the synthesis of red blood cells. A tried-and-true treatment for many malignancies and blood diseases is bone marrow transplantation. Bone marrow banking enables the preservation of these stem cells for use in transplantation.
• Genetic Diversity: In order to address individual differences in treatment outcomes and to advance personalized medicine techniques, it is crucial to assure the availability of stem cells with various genetic origins by banking biological tissues from a variety of populations.
• Dental Pulp Banking: The stem cells found in dental pulp, known as dental pulp stem cells (DPSCs), has the capacity to differentiate into diverse cell types such as neurons, osteoblasts, and adipocytes. Dental pulp banking enables the storage of these stem cells for possible future applications in medicine, such as regenerative dentistry.
• Ethical Considerations: While the use of adult stem cells from tissues such as bone marrow and adipose tissue is not ethically questionable, the destruction of embryos in the process of obtaining embryonic stem cells is. With no ethical issues, induced pluripotent stem cells (iPSCs), which are created from adult cells reprogrammed to resemble embryos, provide an alternative method.
• In order to advance tissue engineering, regenerative medicine, and biomedical research, biological tissues can be banked as sources of stem cells. This can be a valuable resource that could transform healthcare by offering cutting-edge treatments for a variety of illnesses and wounds (17–19).

Drawbacks Or Disadvantages of Stem Cell Therapies:

Although stem cell therapies have enormous potential to cure a wide range of illnesses and wounds, their application is fraught with difficulties and disadvantages.

• Tumorigenic Risk: Potentially uncontrolled tumor growth and creation is one of the main risks associated with stem cell therapy. Given that they can differentiate into any type of cell, The likelihood of pluripotent stem cells developing into cancer is higher. This includes induced pluripotent stem cells, or iPSCs, and embryonic stem cells. Adult stem cells may also have carcinogenic properties under certain conditions.

• Immunological Rejection: In particular, if the cells come from a donor, stem cell therapies may be rejected by the recipient's immune system. In order to avoid rejection, immunosuppressive medications can be necessary, which raises the possibility of infections and other problems.
• Genetic Instability: During long-term growth or manipulation in the lab, stem cells—especially pluripotent stem cells—may experience genetic mutations that might cause genetic instability and could jeopardize the safety of patients receiving stem cell therapy.
• Cost and Accessibility: Due to their high cost, many patients cannot afford stem cell therapies, especially in areas with inadequate healthcare resources. Furthermore, patients may encounter difficulties obtaining experimental or investigational treatments, and the supply of authorized stem cell therapies may be restricted.
• Regulatory Challenges: Stem cell therapies are subject to regulations to ensure safety, efficacy, and ethical standards. It can be difficult and time-consuming to navigate the regulatory approval process, which delays the conversion of promising research into clinical applications.

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