Stem Cell Culture Supernatant is a solution that contains biologically active substances secreted by stem cells during culture, but it does not contain the stem cells themselves. It is rich in extracellular vesicles (EVs), such as exosomes, and cytokines (e.g., growth factors). In recent years, exosomes have gained significant attention and are starting to be used in medical settings. Most of these are derived from mesenchymal stem cell (MSC) culture supernatant or are exosomes isolated from such supernatants.

At our clinic, the stem cell culture supernatant we use is prepared from immortalized, cloned (established) cells of four types of mesenchymal stem cells: dental pulp from baby teeth, umbilical cord, adipose tissue, and bone marrow. This approach ensures the safety, consistency, and stable supply of the formulation. Some concerns have been raised about the risk of “cancerization” from introducing immortalizing genes, but animal testing and RNA analysis have shown the opposite: the introduction of these genes actually suppresses carcinogenesis. These concerns lack scientific basis. Most importantly, the clinical safety of this supernatant has already been demonstrated over eight years of use in human patients.

The Four Types of Mesenchymal Stem Cells:

Dental pulp (from baby teeth)
Umbilical cord
Bone marrow
Adipose (fat) tissue

 

Basic Research on Stem Cell Culture Supernatant

Research in regenerative medicine has primarily focused on cell transplantation. The earliest regenerative medicine technique established was for skin regeneration. Remarkably, this technique was already established in the 1970s. Since then, skin grafts using cultured skin have been performed worldwide and are approved as regenerative medicine products in Japan. Transplanted cultured skin does not remain in the body long-term; it disappears within about two weeks. However, during that time, skin regeneration is stimulated.

Professor Emeritus Minoru Ueda of Nagoya University, who has conducted extensive work with cultured skin grafts, began to question whether actual cell transplantation was truly necessary for regenerative medicine. His research at Nagoya University led to the conclusion that regenerative medicine is indeed possible using the bioactive substances secreted by cells—meaning that actual cell transplantation is not always required. This foundational research supports the clinical applications of stem cell culture supernatant.

Scientific papers related to the following conditions have been published in medical journals.

In addition to this foundational data, our clinic references safety testing from animal studies conducted by the manufacturing contractors, as well as clinical research in humans examining safety and efficacy. We also consider published clinical data from around the world to ensure our treatment proposals are based on scientific validity.

 

Clinical Application of Stem Cell Culture Supernatant

Since the late 2000s, regenerative medicine has been recognized as a next-generation medical field. In 2012, Dr. Shinya Yamanaka’s Nobel Prize in Physiology or Medicine for his work with iPS cells further accelerated interest in the field. Japan has been at the forefront of regenerative medicine research, leading global regulatory efforts. In 2014, the "Act on the Safety of Regenerative Medicine" came into effect. Because stem cell culture supernatant does not contain actual cells, it falls outside the scope of this new law. As a result, clinical application of stem cell culture supernatant is allowed as private medical practice under the Medical Practitioners Act.

From around 2015, advances in technology enabled analysis of microscopic substances, and exosomes (50–150 nanometers in size) have emerged as promising agents for regeneration. Today, exosomes—one type of extracellular vesicle (EVs)—are considered a central player in regenerative medicine.

EVs are bubble-like vesicles secreted by cells. They contain DNA, messenger RNA (mRNA), microRNA (miRNA), proteins, and more. These vesicles facilitate communication between cells and are involved in various physiological processes. miRNA, in particular, plays a critical role—some miRNAs promote healing, while others may trigger or worsen diseases.

Since 2020, exosomes have become increasingly popular, and stem cell culture supernatant and exosome IV drips are now widely offered as private medical treatments. However, many of these formulations lack adequate safety and quality testing, raising concerns about potential medical accidents. Low-quality products can actually increase the risk of disease development or progression.

In July 2024, Japan’s Ministry of Health, Labour and Welfare issued a notice titled “Use of Stem Cell Culture Supernatants and Exosomes in Medical Treatments,” urging clinics to ensure safe medical practices.

At our clinic, we fully understand the quality and risk profile of EVs and are committed to their scientifically grounded use, ensuring patient safety.

 

Ensuring EV Quality

Maintaining high consistency (homogeneity) of EVs is critical. That’s why we only use supernatants derived from cloned (established) cell lines. Because miRNA expression differs depending on the cell source, we select among the four types of mesenchymal stem cell supernatants—dental pulp, umbilical cord, adipose, and bone marrow—based on the treatment.

 

Exosome Content

Our clinic's dental pulp-derived stem cell culture supernatant contains, on average, 40 billion exosomes per milliliter. However, even with current technology, it’s difficult to measure exosome quantities precisely. Recovery rates range from 10% to 50%. Because of this variability, comparing products solely by exosome quantity is not meaningful. Exosome levels can be artificially manipulated by increasing the number of cells during culture or concentrating the culture fluid—and in fact, cancerous or senescent cells tend to produce more exosomes.

Therefore, rather than judging product quality by quantity alone, it is more important to assess whether key miRNAs are being properly and harmoniously expressed.

 

Types and Amounts of Growth Factors

While the type and amount of growth factors in a supernatant may serve as indicators of product uniformity, they may not directly correlate with therapeutic effect.

What matters more is the body's internal response to the supernatant. The treatment effect comes from proteins synthesized within the body or cells as needed. Again, it’s the balanced expression of important miRNAs that plays a vital role.

 

Mechanism of Recovery and Regeneration

Suppressing Inflammation
The first effect is to suppress inflammation. Damaged organs typically exhibit strong inflammation, and stem cell culture supernatant helps calm this response, creating an environment conducive to regeneration.
Cell Protection
The second effect is protecting cells that have been damaged by inflammation, minimizing further tissue destruction.
Attracting Stem Cells
The third effect is attracting the body’s own stem cells to the damaged site, guiding them from elsewhere in the body.
Angiogenesis (New Blood Vessel Formation)
The fourth effect is stimulating the formation of new blood vessels, which are essential for regeneration. These new vessels deliver oxygen and nutrients to the damaged tissue, enabling recovery.