How Scientists Are Unlocking New Stem Cell Potential
Once considered biological waste, the human placenta is now revolutionizing regenerative medicine.
For centuries, the human placenta was typically discarded after birth, its biological使命 considered complete. Today, this temporary organ is undergoing a dramatic image transformation—from biological waste to medical treasure chest. The placenta serves as a lifeline between mother and baby, delivering oxygen and nutrients to the developing fetus while removing waste products 2 5 .
Within this complex, multifunctional organ lies an abundance of specialized stem cells with remarkable healing properties. Recent breakthroughs in molecular science have uncovered the placenta's hidden potential, positioning it as a key player in regenerative medicine and the treatment of degenerative diseases 1 9 . What scientists are discovering about these cells could transform how we treat conditions ranging from pregnancy complications to autoimmune disorders and erectile dysfunction.
Understanding the Key Players
Placenta-derived mesenchymal stem cells (PD-MSCs) are the most extensively studied placental stem cells. These cells are abundant in both the placenta and amniotic membranes, making them readily available for research and clinical applications 1 .
Their therapeutic effects depend primarily on paracrine activity—the secretion of anti-inflammatory cytokines and specific exosomes that modulate the immune system and promote tissue repair 1 .
Trophoblast stem cells (TSCs) are more specialized and elusive than their mesenchymal counterparts. These specialized placental cells form the interface between maternal and fetal tissues, playing crucial roles in nutrient transport and blood vessel remodeling 1 2 .
Until recently, TSCs could only be isolated from blastocyst-stage embryos or first-trimester placental tissue, making the procedure quite demanding and limiting research opportunities 1 .
Located in the amniotic mesenchyme, human amniotic mesenchymal stromal cells (hAMSCs) represent another promising placental stem cell population 6 . These cells exhibit hybrid epithelial-mesenchymal properties at the ultrastructural level and demonstrate impressive therapeutic potential 6 .
What makes hAMSCs particularly valuable is their high proliferation capacity and expression of pluripotency markers, suggesting they may represent a primitive form of stem cell 6 .
For years, researchers believed that the source of trophoblast stem cells disappeared during late pregnancy, as deriving these cells from full-term placentas had proven extremely difficult. A groundbreaking study from Japan has recently overturned this long-standing assumption 2 5 .
Led by Professor Masatsugu Ema and Assistant Professor Masanaga Muto at Shiga University of Medical Science, the research team successfully isolated trophoblast cells from the smooth chorion, the outermost fetal membrane of full-term placentas 2 5 . From this tissue, they established stable trophoblast stem cell lines called Ch-TS cells 2 .
| Property | Significance |
|---|---|
| Origin | Smooth chorion of full-term placentas 2 |
| Differentiation Potential | Can develop into extravillous trophoblasts and syncytiotrophoblasts 2 |
| Gene Expression | Similar to trophoblast stem cells from early pregnancy 2 |
| Research Advantage | Enables study of late-pregnancy complications with relevant cells 2 5 |
| Ethical Advantage | Avoids ethical concerns associated with early pregnancy tissue 2 |
Researchers obtained smooth chorion tissue from full-term placentas after birth 2 .
They isolated trophoblast cells from this tissue using specialized laboratory techniques 2 .
The isolated cells were cultured under specific conditions that allowed them to multiply while maintaining their stem cell properties 2 .
The resulting Ch-TS cells were thoroughly analyzed to confirm they possessed the key characteristics of genuine trophoblast stem cells 2 .
The therapeutic potential of placental stem cells extends far beyond pregnancy-related conditions. Recent clinical research demonstrates their remarkable versatility in treating diverse medical conditions.
A recent phase 1 clinical trial investigated placenta-derived mesenchymal stem cells (PLMSCs) for treating secondary progressive multiple sclerosis (SPMS) 4 .
The results were promising: not only was the treatment safe and well-tolerated, but patients also demonstrated significant improvements in clinical outcomes 4 .
Similarly, research on Crohn's disease has shown that human placenta mesenchymal stromal cells (hPMSCs) can alleviate intestinal inflammation and repair damaged intestinal barrier function .
A 2025 clinical trial explored high-activity placenta-derived mesenchymal stem cells (hPMSCs) for treating diabetic erectile dysfunction (ED) 3 .
| Treatment Group | Erection Hardness Score (EHS > 2) | Total Erection Time (minutes) |
|---|---|---|
| hPMSCs only | Data not specified | Data not specified |
| LI-ESWT only | Data not specified | Data not specified |
| Combined Therapy | 70% of patients 3 | 22.20 3 |
The combined therapy group demonstrated significantly superior outcomes compared to either treatment alone, suggesting a synergistic effect 3 .
Research has also advanced in developing endothelial progenitor cells (EPCs) from placental tissue 7 8 . These precursor cells of vascular endothelial cells play a pivotal role in vasculogenesis and vascular repair 7 .
A recent study established an animal-free culture system for expanding EPCs from human placenta, addressing safety concerns associated with traditional fetal bovine serum 7 8 . The system yielded high-purity EPCs that demonstrated excellent functional capacity in tube formation, migration, and wound repair in animal models 7 .
Key Research Reagents and Techniques
Advancements in placental stem cell research rely on specialized reagents and laboratory techniques that enable scientists to isolate, characterize, and manipulate these cells.
| Tool/Reagent | Function | Example Applications |
|---|---|---|
| Flow Cytometry | Cell characterization using surface markers 4 7 | Identifying CD73, CD90, CD105 on MSCs; CD133, CD34 on EPCs 4 7 |
| Animal-Free Culture Media | Ethical, safe cell expansion 7 | Growing EPCs with bFGF, IGF, VEGF supplements 7 |
| Growth Factors (VEGF, bFGF, IGF) | Promote cell growth and differentiation 7 | EPC induction and expansion 7 |
| Differentiation Media | Direct stem cell specialization 4 6 | Creating osteocytes, adipocytes, chondrocytes from MSCs 4 6 |
| Functional Assays | Test cell capabilities 7 | Tube formation, migration, Ac-LDL uptake for EPCs 7 |
As the field matures, developing clear, standardized isolation and characterization protocols will be essential for comparing results across studies and advancing toward clinical applications 6 .
The transition of human placental derivatives from "biowaste" to valuable biomedical resources represents a significant shift in both scientific and ethical perspectives on tissue repurposing 9 . With their abundant availability, minimal ethical concerns, and potent therapeutic properties, placental stem cells are poised to continue transforming regenerative medicine in the coming years.
As research progresses, these remarkable cells offer hope for millions affected by degenerative diseases, autoimmune disorders, and various injuries—proving that even after birth, the placenta continues to give life.