As life science research continues to advance, humanity’s understanding of stem cells has deepened steadily, and stem cell-related scientific breakthroughs are playing an increasingly vital role in areas such as disease treatment and regenerative medicine. By leveraging stem cell technology, we can now tackle previously intractable conditions like leukemia and immune system disorders, while also paving the way for organoid technologies that accelerate new drug development, support precision medicine, and even hold the potential to revolutionize regenerative medicine—opening up possibilities like treating Alzheimer’s disease or repairing aging organs. In short, stem cell research and its applications continue to safeguard the health and well-being of people worldwide.

To understand stem cells, you first need to grasp what cells are. As we all know, cells are the fundamental building blocks of the human body. An adult typically has anywhere from 40 to 60 trillion cells. These cells—not only are they incredibly numerous but also highly specialized in their functions. For instance, nerve cells govern thought processes, muscle cells enable movement, fat cells store energy, and immune cells play a critical role in defending against pathogens, among other vital roles. Different types of cells then come together to form tissues, organs, and even entire systems, allowing the human body to carry out its diverse range of life-sustaining activities. Remarkably, all these varied cell types initially originate from a single cell—the fertilized egg—at the very beginning of life. From this single cell, embryonic stem cells multiply, giving rise to an ever-growing embryo. Over time, these stem cells continue to divide and specialize, eventually differentiating into more than 200 distinct cell types that make up the human body—and ultimately lead to the development of a fully formed individual.

Just as a tree trunk can give rise to branches, twigs, and leaves—and eventually blossom and bear fruit—stem cells are a special type of progenitor cell capable of both self-renewal and differentiating into various types of specialized cells. During an organism’s development, stem cells multiply and transform into diverse cell types, ultimately forming tissues and organs. After development is complete, when tissues or organs are damaged, inflamed, or when internal homeostasis shifts, stem cells act as "seed cells," differentiating and replenishing the specific cell types needed to restore and repair the affected areas. However, as life nears its end, when stem cell vitality declines and their ability to replace aging or deteriorating cells becomes insufficient, the organism begins to exhibit signs of aging.

Stem cells can be classified into two main categories based on their developmental stage: embryonic stem cells and adult (or somatic) stem cells. Embryonic stem cells are derived from the inner cell mass of early-stage embryos—essentially "cells of infinite potential," as they theoretically have the ability to differentiate into virtually any cell type in the body. These cells can be efficiently expanded, cryopreserved, and revived in vitro without losing their original characteristics. In contrast, adult stem cells, also known as tissue-specific or somatic stem cells, are undifferentiated cells naturally present in mature tissues. They possess remarkable abilities: not only can they self-renew indefinitely, but they can also specialize into the specific types of functional cells that make up the tissue itself—much like a "cellular manufacturing plant." To date, several types of adult stem cells have been identified, including hematopoietic stem cells found in bone marrow, mesenchymal stem cells from bone marrow, neural stem cells in the brain, muscle stem cells in skeletal muscle, epidermal stem cells in skin, and retinal stem cells in the eye's retina.

Stem cells can be classified into three categories based on their differentiation potential: totipotent, pluripotent, and unipotent stem cells. As the names suggest, totipotent stem cells have the unique ability to differentiate into any cell type in the body and possess the full developmental potential to form a complete organism—examples include embryonic stem cells. Pluripotent stem cells, while capable of generating multiple types of cells, cannot develop into a fully formed individual. For instance, hematopoietic stem cells can give rise to various blood cell types, and bone marrow mesenchymal stem cells can differentiate into cells belonging to mesodermal tissues, such as bone, cartilage, muscle, and fat. In contrast, unipotent stem cells are restricted to differentiating into just one specific cell type within adult tissues and organs.

Health is everyone's aspiration, and in the fields of disease treatment and regenerative medicine, stem cells hold tremendous potential. Some developed countries have already taken the lead in using stem cell transplantation techniques to treat various illnesses, and China is also actively advancing clinical research into stem cell-based therapies. According to statistics, among the more than 6,000 stem cell clinical trials conducted worldwide, hundreds of diseases are being targeted.

Perhaps the most familiar application to the public is the treatment of blood disorders. Hematopoietic stem cell transplantation is one of the earliest and most common clinical uses of stem cells, primarily targeting conditions like anemia and leukemia—including aplastic anemia, congenital hematopoietic cell deficiencies, and chronic myeloid leukemia. This therapy is also being explored for certain rare or complex diseases, such as severe combined immunodeficiency and autoimmune disorders like multiple sclerosis. In these cases, the stem cells used are typically derived from umbilical cord blood or bone marrow. Historically, diseases in this category were often difficult to treat—but today, stem cell therapies offer new hope to patients who once faced bleak prospects.

For instance, in the treatment of skin-related conditions: Stem cells are present in various skin tissues, such as the epidermis, hair follicles, and dermis, playing a crucial role in maintaining the skin’s dynamic balance and facilitating injury repair. Stem cell therapy has proven effective for treating skin damage—back in 2017, scientists successfully regenerated human epidermis using stem cells, giving a young boy entirely new skin. Today, this groundbreaking technique is already being applied to patients suffering from severe burns. During the healing process of epidermal wounds, mesenchymal stem cells accelerate wound closure and minimize scarring by promoting key biological processes like cell migration, angiogenesis, epithelialization, and granulation tissue formation. Moreover, impaired stem cell function is a major contributor to the dysregulated inflammatory responses seen in psoriasis. Clinical trials have demonstrated that patients who underwent stem cell therapy experienced long-term relief from psoriasis symptoms. In addition to these applications, stem cell therapies are also being explored for treating androgenetic alopecia (male pattern baldness) and alopecia areata, including innovative approaches such as hair follicle transplantation and stem cell-stimulating treatments.

In addition to using stem cells directly for disease treatment, various cutting-edge technologies based on stem cells also hold tremendous potential for practical applications. For instance, organoids—tissue-like structures derived from adult stem cells—are not only crucial tools for studying organ development and disease mechanisms but also offer promising avenues in areas such as personalized cancer therapy, drug discovery, and regenerative medicine. Organoids are mini-organs cultivated in vitro with a three-dimensional structure, featuring the intricate architecture of their real-life counterparts—and they can even partially mimic the physiological functions of the tissues or organs they originate from. Take cancer treatment as an example: while current drugs are often generic, each patient’s condition is unique. By replicating a patient’s own organoid model, researchers can identify the most effective therapies tailored specifically to that individual, paving the way for personalized medicine. In drug development, organoids provide a more accurate representation of human diseases, helping to reduce costs and accelerate the process of bringing new treatments to market.

In the future, the most promising application of stem cells may lie in regenerative medicine. Alzheimer's disease is a neurodegenerative disorder, and researchers are exploring the use of stem cell technology to replace damaged neurons, with the hope of developing effective treatments for Alzheimer's. Moreover, stem cell therapies hold great potential for repairing aging organs, enabling people to live longer, healthier lives filled with greater quality of life.

China boasts a strong foundation in stem cell research and its applications, having achieved a series of significant breakthroughs. In terms of research, Chinese scientists have successfully demonstrated the pluripotency of induced pluripotent stem cells for the first time—using tetraploid blastocyst injection. They’ve also pioneered semi-cloning technology, enabling the creation of mouse haploid embryonic stem cell lines derived from parthenogenetic activation (also known as "sperm-like" stem cells), which can functionally replace sperm to produce healthy offspring. Additionally, stem cells have been used to restore vision in mice born blind due to congenital defects. In terms of applications, Chinese researchers have made groundbreaking contributions by establishing the world’s first human fetal pancreatic stem cell line, providing a valuable cellular resource for potential clinical treatments of diabetes. Furthermore, they’ve leveraged umbilical cord mesenchymal stem cells to improve ovarian blood flow and regenerate ovarian function, helping prematurely aging ovaries regain their reproductive capacity. These breakthroughs in stem cell technology have propelled China's research and applications in the field, reflecting a transformative shift—from "following" to "running alongside"—and now aiming to take the lead in the global stem cell arena.

Life and health are not just scientific issues—they are profound, universal questions that everyone must confront. Achieving a vibrant, healthy body is a simple yet deeply cherished aspiration for people everywhere, and it also remains the ultimate goal of stem-cell researchers. As a cutting-edge and rapidly evolving field within life sciences, stem cells still hold many unanswered mysteries that call for our relentless exploration. With each new breakthrough, stem cells continue to unlock innovative treatment strategies for complex and challenging diseases, paving the way for even greater contributions to human health in the years to come.