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Fundamentals of Stem Cell Therapy in Disease Prevention

Rajarshi Nath, Arijit Das, Shambo Panda, Souvik Biswas and Biplab Debnath*

Department of Pharmaceutical Technology, Bharat Technology, Uluberia, Howrah, WB, India

Abstract

Stem cell therapy is a possible method of treating most diseases and restoring damaged tissue. In this review, the history, mechanism, application, problems, and prospects of stem cell therapy are summarized. Self-renewal and differentiation into other cell types are key features of stem cells. There, they can be obtained from embryonic, adult, and induced pluripotent sources. Stem cells can replace damaged cells, modulate the immune system, and secrete factors that facilitate the healing of tissues. Stem cell therapy has been researched for the treatment of neurological diseases, cardiovascular diseases, autoimmune diseases, and other conditions. However, other problems have to be solved, such as tumorigenesis risk. Recent progress in technologies of induced pluripotent stem cells and gene-editing technologies, such as CRISPR-Cas9, has provided new opportunities for personalized and targeted stem cell therapies. In the future, we also need to develop safer, more effective, and more accessible stem cell-derived therapies. Consequently, laws should be created to guarantee the clinical implementation and safe evolution of these medications. Although stem cell treatment presents great possibilities for revolutionizing regenerative medicine and enhancing patient outcomes, its advantages can only be fully appreciated by coordinated efforts among scientists, doctors, and legislators.

Keywords: Stem cells, regenerative medicine, embryonic stem cells, adult stem cells, induced pluripotent stem cells, hematopoietic stem cells (HSCs), homology-directed repair

1.1 Introduction to Stem Cell Therapy

Stem cells are a unique class of cells that are thought to have the ability to differentiate into a different cell type. They have a capacity of long-term renewal and proliferation, which could be effective in different regenerative medicine applications. Derived from a variety of sources, stem cell therapy is believed to be a promising treatment option for end-stage diseases that conventional therapies are unable to cure [1]. Since the 1950s and 1960s, interest in the field has been increasing; its history and major developments indicating therapeutic potential and anticipated diseases are discussed.

Conventional therapies for different diseases such as diabetes, myocardial infarction, bone disorders, etc., are generally focused on controlling the symptoms or curing them to a certain extent until the end-stage disease is reached. End-stage diseases have no further therapy, including surgery or transplantation, other than a fully viable organ or tissue transplantation. In the meantime, transplantation is limited due to a lack of supply, immune problems, and being an invasive procedure. Because of the efficacy in organogenesis and histogenesis, stem cells provide a promising treatment for these kinds of end-stage diseases. They can proliferate and differentiate into a variety of cell types. Moreover, they can self-renew and have a capacity for long-term renewal [2]. Adult or tissue-specific stem cells residing in various parts of the body have been successfully used for over 40 years in bone marrow transplantation. In summary, a variety of stem cells from multiple sources have been considered a potential treatment for many diseases, including differentiation into a wide range of cell types and appropriateness for different regenerative medicine applications [3].

1.1.1 Definition and Types of Stem Cells

Stem cells self-renew and differentiate into many different cell types, which means that they have potential applications in cell therapy, tissue repair, and disease modeling. Stem cells have two very special mechanisms that make them different from other cells; first, they can divide indefinitely while maintaining an undifferentiated state and are able to differentiate into multiple cell types. These properties are known as self-renewal potential and plasticity, respectively. There are several different types of stem cells that can be characterized by their origin, functioning activity, and applications [2]. The classification of stem cells is divided into embryonic stem cells, adult stem cells, and induced pluripotent stem cells (iPSCs).

The abundance of stem cells with a lot of potential application and the discovery of direct conversion methods provide a clear path for future research in stem cell biology and regenerative medicine. Stem cell regeneration is fundamentally regenerative during development and homeostasis due to the highly coordinated and tightly regulated nature of cellular signaling pathways, niche interactions, and epigenetic mechanisms that ensure precise cell fate decisions, tissue patterning, and organogenesis. During embryonic development, stem cells exhibit remarkable plasticity and proliferative capacity, enabling them to generate all tissue types in a highly orchestrated manner. In adult homeostasis, stem cells maintain and repair tissues by responding to routine cellular turnover and minor injuries, guided by cues from their microenvironment. However, this regenerative potential often diminishes or becomes dysregulated in response to severe injury, aging, or chronic disease. Since the first report, a lot of interest and numerous studies related to the biological impact and technical improvement of transdifferentiation already explain the conversions themselves, i.e., how the fibroblasts can be converted. Nevertheless, the vast untapped potential of stem cells in therapeutic applications is challenged by the limited availability of these primary sources. As an alternative, the conversion of mature cells into stem-like states has emerged as a promising strategy. However, this process often involves the use of heterokaryons and results in incomplete differentiation or imperfect cellular reprogramming. Consequently, achieving direct and functional replacement of damaged tissues or organs remains a complex and ongoing challenge, highlighting the need for further advancements in stem cell research and regenerative medicine [4].

1.1.2 Historical Background

The field of stem cell biology first gathered momentum with the groundbreaking research of A. Maximow in the late 19th century. However, the "classical era" of this science started with the isolation of hematopoietic stem cells (HSCs) by Till and McCulloch in 1962, which marked the start of an energetic and expanding investigation field in the biology of normal and cancer stem cells. In 1998, James Thomson and colleagues derived the first human embryonic stem (ES) cell line. Two years later, John Gearhart derived the first human embryonic germ cell line. These works opened new possibilities for cell-based therapies and led to an enormous scientific production [5]. A steering position of Chinese authorities was noticed as they gave substantial financial, media, and legal support for the use of HSCs. Regulations were drafted that blocked the expansion of large international clinical trials on adult stem cells in China. Indistinctively, Chinese HSC scientific community's voice has been raised against the utilization of the unsupported data. The academic debate between Chinese and Western HSC experts is a striking example of unbalanced competition in the global scientific context. Stem cell research reflects broader concerns such as health policy, the role of scientific expertise, and the relations between science and state. Ethical governance of stem cell research and therapy in Chinese regulatory provisions was analyzed, concerning not only adult but also ES and iPSCs [1].

Despite the considerable public interest in the field, there remain many scientific and technical hurdles still to be negotiated. Over the past decades, advances in human stem cell biology have come in fits and starts, some being the product of rigorous research, but many others of anecdotal use of poorly understood treatments. However, there is room for optimism given the powerful tools and techniques developed, as well as promising preliminary scientific results. Stem cell treatments should still be seen as investigational, and with the exceptions of bone marrow transplants and some skin transplants, any other treatments cannot be considered as originating from established medical practice. Nonetheless, much can be done to expedite the responsible progress of medical research using human stem cells. As a part of this effort, in the short term, more research is required to rigorously detect cancerous and precancerous formations in the products of stem cell differentiation. Longitudinal epidemiological studies of patients would also be a good practice, conducting an annual check-up and medical scan for at least a decade after cells are transplanted to detect solid tumor and leukemia formations [6].

1.2 Mechanisms of Stem Cell Therapy

A plenitude of human diseases is characterized by an effective attrition of cells and ultimately tissues. When this happens, the human organism is essentially unable to regenerate the damaged tissue, and the healing process is therefore doomed to heal via formation of scar tissue with impaired function. Many conditions such as neurodegenerative diseases, heart infarct and diabetes, to cite a few, are typified by this mechanism, and in such cases, adult stem cell therapy represents an appealing approach for curing these diseases. The concept behind stem cell-based...