Stem Cells, Exosomes and Secretome

Key Takeaways

There are many kinds of stem cells, but MSCs (mesenchymal stromal/stem cells) are particularly relevant to regenerative-medicine discussions. They are living cells that can respond to their surrounding environment and release biological signals. This paracrine activity is one reason researchers are studying MSCs for tissue repair, inflammation and other conditions.[1][2]

MSCs can come from different tissues, including bone marrow, adipose tissue and perinatal tissues such as umbilical cord or Wharton's jelly. Cells from different sources are not automatically identical, and their behaviour can also be influenced by donor factors, culture conditions, passage, storage and manufacturing.[1][2]

Secretome is different. It is a broad biological term for the substances released by cells. Depending on the source cells and culture conditions, a secretome may contain proteins, cytokines, chemokines, lipids, growth-related signalling molecules and extracellular vesicles.[4]

Exosomes sit at a narrower level. They are a specific term within the extracellular-vesicle field. Current MISEV2023 guidance recommends using the broader term 'extracellular vesicle' unless the relevant biological origin and characteristics of a specific vesicle population have been demonstrated. In commercial settings, the word 'exosome' is sometimes used much more loosely.[3]

Because a label does not tell you the whole treatment. A product described as 'stem-cell derived exosomes' is not the same as administering living stem cells. Likewise, calling something 'secretome' does not tell you whether it contains a particular purified component, a mixture of soluble factors and vesicles, or how consistently it is manufactured.[3][4][6]

I would therefore avoid the question, 'Which is better, stem cells or exosomes?' They are biologically different approaches. The more useful question is: what clinical problem are we trying to address, and what evidence exists for this exact product and route?[3][4][6]

There is no single mechanism shared by every cell, secretome or EV product. Researchers are studying effects on inflammatory signalling, cell survival, blood-vessel formation, cell migration, extracellular-matrix remodelling and communication between cells.[3][4]

For living MSCs, effects may involve direct cell interactions, differentiation in some settings and paracrine signalling. For secretome or EV-based approaches, the intended effect is generally mediated by substances and particles released by cells rather than by the continued presence of living therapeutic cells.[3][4]

A plausible mechanism is useful for understanding why a treatment might work. It is not proof that a clinically meaningful benefit occurs in humans.[3][4]

For patients, I think the most important shift is to stop asking whether a whole category is 'promising' and instead ask what has actually been demonstrated for the exact intervention. Laboratory findings can explain biology, but they do not establish the size, durability or safety of a benefit in people.[3][6]

The evidence is indication-specific. Established stem-cell medicine exists, including haemopoietic stem-cell transplantation for selected blood and immune disorders. That established use should not be used to imply that every treatment marketed as a stem-cell therapy is established.[6]

For MSCs, secretome and extracellular-vesicle approaches used for tissue repair, musculoskeletal conditions, neurological conditions, wound healing, aesthetics or wellness, the evidence varies by product and condition. Much of the secretome and EV field remains translational or early clinical research.[3][4]

A useful way to read the evidence is to move from laboratory and animal studies, through observational and early human studies, toward well-controlled human trials. Higher-level evidence can strengthen a clinical claim, but study quality, follow-up, product consistency and whether the studied product matches the one being offered still matter.[3][6][7]

One study of an EV preparation cannot automatically validate another preparation simply because both are called 'exosomes'. The source cells, culture conditions, isolation method, composition, concentration, storage and characterisation can all differ.[3][6][7]

Neither conclusion follows automatically. Patients are sometimes shown numbers such as 50 million or 100 million cells. Dose may matter, but the number means little without the cell identity, viability, source, passage, manufacturing method, route and treatment goal. More cells is not automatically better treatment.[3][7]

Similarly, cell-free does not mean risk-free. Removing living cells may avoid some risks associated with viable-cell administration, but the product can still have risks related to biological activity, contaminants, immune or inflammatory reactions, manufacturing quality, route of administration and effects that are not yet well understood.[7][8]

For cell products, manufacturing is part of the treatment story. Questions about identity, sterility, viability, storage, transport and release testing are not technical details to ignore. Good manufacturing supports confidence in how a product is made, but it does not by itself prove that the product works for a particular clinical indication.[3][7][8]

Passage is another manufacturing detail worth understanding. MSCs may be expanded in culture to produce enough cells, and repeated expansion can affect cellular characteristics. I would be cautious about claims that one passage number is universally 'best'. What matters more is whether the manufacturing process is validated and whether the final product meets its intended quality specifications.[3][7][8]

Malaysia has a dedicated National Pharmaceutical Regulatory Agency (NPRA) framework for cell and gene therapy products (CGTPs). The current second edition of the Malaysian Guidance Document and Guidelines for Registration of CGTPs was updated in September 2025. The existence of this framework means therapeutic cell and gene products are subject to a defined regulatory system rather than being outside oversight simply because they are described as regenerative or stem-cell products.[10]

Malaysia's Ministry of Health also publishes guidance on stem-cell and cell-based research and therapy, as well as national guidance for haemopoietic stem-cell therapy. For a patient, the important point is that regulatory status is product- and use-specific.[11][12]

For exosome and secretome products, do not assume that every commercial product automatically falls under the CGTP framework. The applicable category can depend on the product's composition and intended use. If a provider says a product is 'NPRA approved' or 'registered', ask for the exact product name, the relevant registration or authorisation, the approved or authorised indication and the documentation supporting the statement. If the treatment is investigational, ask whether it is being provided within an appropriately authorised clinical study.[6][10]

I would ask these questions before discussing payment or scheduling treatment:

MSCs, secretome and exosomes are connected through cell communication, but they describe different biological things. MSCs are living cells. Secretome is a broader mixture of material released by cells. Extracellular vesicles are one part of that system, while 'exosome' is a more specific term that requires careful use.[1][3][4]

For a patient, the important decision is not whether one label sounds newer or more powerful. It is whether the exact product is well characterised and manufactured, whether there is human evidence for the exact condition and route, what the known and uncertain risks are, and what regulatory status applies in Malaysia.[6][7][10]