By Joseph Purita, MD
Authenticity is not a matter of terminology. It is a matter of biological identity, scientific rigor, and patient safety.
A growing number of products have entered the marketplace under the name “MUSE” cells, yet many lack demonstrated provenance from the scientifically validated platform developed by Dr. Mari Dezawa at Tohoku University.
The distinction at the center of this paper
Authentic Dezawa MuseCells® are defined by a specific, experimentally validated phenotype — a naturally occurring, non-tumorigenic, pluripotency-like cell population found within various human tissues and routinely isolated using the SSEA-3 pluripotent surface marker.
This distinction matters because the therapeutic effects of the Dezawa MuseCell® platform rest on properties that are highly specific and not interchangeable with those of other cell products. The defining value of authentic Dezawa MuseCells® lies in their capacity for broad differentiation and endogenous tissue repair, without the tumor-forming behavior that has limited the therapeutic use of embryonic and induced pluripotent stem cells.
That is not a generic characteristic of any product labeled “MUSE.” It is the result of a distinct cell identity, carefully defined through years of preclinical and translational research.
Scientific Foundation
The scientific foundation for Muse cells was established in the landmark work from Dr. Dezawa’s group, including the original PNAS reports that identified and characterized multilineage-differentiating stress-enduring (MUSE) cells in adult human tissues and extraembryonic tissues such as umbilical cord and amnion.
The 2010 PNAS paper first described unique pluripotent cells in adult human mesenchymal cell populations. The 2011 PNAS paper established the SSEA-3⁺/CD105⁺ co-marker isolation protocol and demonstrated that iPS cells generated from human fibroblasts derive exclusively from the Muse subpopulation.
These studies showed that authentic Dezawa MuseCells® possess self-renewal capacity, triploblastic differentiation potential across mesoderm, ectoderm, and endoderm lineages, and a non-tumorigenic, pluripotent-like profile. They also showed that SSEA-3 selection improves the precision of Dezawa MuseCell® isolation from the broader mesenchymal stem cell population.
The Biology That Cannot Be Replicated Without Proper Protocol
The non-tumorigenic pluripotency of authentic Dezawa MuseCells® is one of the most scientifically significant – and most frequently misunderstood – properties in regenerative cell therapy.
Traditional pluripotent stem cells, such as iPSCs, carry an inherent risk of teratoma formation because their reprogramming introduces genomic instability and reactivates oncogenic pathways. Dezawa MuseCells® sidestep this entirely through a distinct mechanism.
Several features underpin this safety profile.
Authentic Dezawa MuseCells® are isolated through a long-term, severe cellular stress protocol involving trypsin incubation, serum deprivation, and hypoxia. This process selectively enriches the Dezawa MuseCell® population while eliminating less-resilient, potentially unstable cells. This is not a cosmetic step. It is biologically determinative.
Unlike iPSCs, Dezawa MuseCells® do not require the reprogramming factors Oct4, Sox2, Klf4, or c-Myc. Their pluripotency is intrinsic rather than induced — meaning their genome remains intact and oncogenic activation is avoided.
Following engraftment, Dezawa MuseCells® spontaneously differentiate into tissue-specific cell types in response to local microenvironmental cues — without requiring directed differentiation protocols.
The Molecular Mechanism of Dezawa MuseCell® Homing
One of the most elegant and scientifically distinctive features of authentic Dezawa MuseCells® is their highly specific homing mechanism — a precision targeting system that sharply differentiates them from generic MSCs and underscores why protocol integrity is inseparable from function.
When tissue is damaged or cells undergo apoptosis, they release sphingosine-1-phosphate (S1P), a bioactive lipid mediator that acts as a molecular distress signal. Authentic Dezawa MuseCells® express sphingosine-1-phosphate receptor 2 (S1PR2) on their surface, conferring sensitivity to this gradient.
“A label is not a biology. A name is not a safety profile.”
The S1P–S1PR2 axis is the primary molecular engine driving Dezawa MuseCell® homing. Studies demonstrated that blocking or silencing S1PR2 abolished homing capacity entirely, confirming that S1PR2 is mechanistically required for targeted migration to damaged tissue.
This S1PR2-driven homing is distinct from the mechanism used by monocytes and macrophages, which migrate toward S1P gradients via S1PR1 rather than S1PR2.
The homing cascade proceeds through several coordinated steps:
- Damaged tissue releases S1P into the bloodstream and tissue microenvironment
- Circulating Dezawa MuseCells® detect the gradient through S1PR2
- Cells migrate toward the injury site and undergo diapedesis through the vascular endothelium
- Cells engraft into damaged tissue and differentiate into tissue-appropriate cell types
Recent data from ALS clinical trials also showed that serum S1P levels decreased continuously over 12 months following Dezawa MuseCell® infusion, suggesting that engrafted cells may functionally neutralize ongoing damage signals.
Clinical Validation: A Decade of Human Evidence
The safety and preliminary efficacy of authentic Dezawa MuseCells® have been evaluated in a growing body of human clinical trials, primarily under the development of the CL2020 intravenous allogeneic product derived from bone marrow.
Conditions evaluated in human trials include:
- Ischemic stroke
- Amyotrophic lateral sclerosis (ALS)
- Acute myocardial infarction
- Dystrophic epidermolysis bullosa
- Neonatal hypoxic-ischemic encephalopathy
- Cervical traumatic spinal cord injury
Ischemic Stroke
A randomized placebo-controlled Phase II trial demonstrated meaningful improvement in functional outcomes, with a substantially higher proportion of treated patients regaining independence compared to placebo.
Amyotrophic Lateral Sclerosis (ALS)
An open-label Phase II trial confirmed safety, with no pulmonary embolism, anaphylactic shock, or serious adverse events attributed to treatment. Some patients also showed slowing of disease progression markers.
Acute Myocardial Infarction
A first-in-human trial administering a single intravenous dose to STEMI patients demonstrated no adverse drug reactions and improvements in left ventricular function over follow-up.
Dystrophic Epidermolysis Bullosa
A Phase 1/2 open-label study demonstrated tolerability without major safety concerns. Some patients showed substantial reduction in refractory ulcers following a single infusion.
Neonatal Hypoxic-Ischemic Encephalopathy
The SHIELD trial demonstrated encouraging early safety findings in neonates receiving therapeutic hypothermia, with many infants showing developmental outcomes within normal ranges at follow-up.
Cervical Traumatic Spinal Cord Injury
A multicenter clinical trial demonstrated favorable safety and tolerability, with statistically significant improvements in motor function, activities of daily living, and quality-of-life measures.
Across these human clinical trials, no reports of tumor formation, immune rejection requiring immunosuppression, or serious adverse events attributable to the cells themselves have emerged.
This safety record is the direct consequence of validated derivation. It is not a generic property of any loosely defined cell population.
The Danger of Unverified “MUSE” Products
Products marketed under the “MUSE” label that were not produced using Dr. Dezawa’s validated protocols are not authentic Dezawa MuseCells®.
Their phenotypic identity, functional S1PR2 expression, genomic stability, and safety profile remain uncharacterized.
This creates several layers of serious risk:
Tumorigenicity Risk
Without the stress-selection protocol and verification of SSEA-3-positive phenotypes, there is no scientific basis to assume non-tumorigenic behavior.
Homing Failure
Without verified S1PR2 expression, cells cannot be expected to home to injury sites with the precision fundamental to the Dezawa MuseCell® therapeutic mechanism.
Inappropriate Engraftment
Cells not verified for controlled trilineage differentiation may fail to integrate appropriately into tissue.
Immune Response
Authentic Dezawa MuseCells® have a well-characterized low immunogenicity profile. Unverified products lack this established profile and may provoke inflammatory or rejection responses.
“Clinicians using unverified products inherit the uncertainty of those products, a risk that patients have not knowingly accepted.”
What Authentic Characterization Requires
For a product to legitimately claim Dezawa MuseCell® identity, it must meet the following scientifically established criteria:
- Expression of SSEA-3 confirmed by flow cytometry
- Derivation through validated stress-selection methodology
- Demonstrated trilineage differentiation capacity in vitro
- Confirmed S1PR2 expression and functional S1P-mediated homing
- Confirmed non-tumorigenic behavior in animal xenograft models
- Validated genomic stability
- Manufacturing under GMP-compliant conditions with full lot-release testing
These are not optional quality benchmarks. They are the minimum scientific requirements for legitimate association with the Dezawa MuseCell® platform.
An Inflection Point
As a physician deeply engaged in regenerative medicine, Joseph Purita, MD argues that authentic Dezawa MuseCells® represent one of the most compelling and rigorously developed platforms in cellular therapy today.
The regenerative medicine community must hold itself to the same evidentiary standards expected of any serious therapeutic platform.
The S1PR2-mediated homing precision, intrinsic non-tumorigenic pluripotency, and validated trilineage differentiation of authentic Dezawa MuseCells® do not transfer by nomenclature alone.
“Authentic Dezawa MuseCells® earned their scientific credibility through decades of rigorous investigation. Products that appropriate that name without earning it do not share that credibility, and must not be permitted to trade on it at the expense of patient safety.”
When the field protects the integrity of scientifically validated platforms, it safeguards not only the credibility of regenerative medicine, but also the opportunity for transformative therapies to reach the patients who need them most.
— Joseph Purita, MD
