From Message to Messenger: The Cellular Secretome in Precision Medicine

In our previous issue, we discussed the growing interest in exosomes as key mediators in regenerative therapies based on mesenchymal stromal cells (MSCs). The discussion took place in an exceptional scientific context: the awarding of the 2024 Nobel Prize in Medicine to Katalin Karikó and Drew Weissman for their contributions to the development of messenger RNA as a therapeutic platform.

The global recognition of these discoveries not only validated new biomedical tools but also highlighted the central role of intercellular communication in modern biology. In this new issue, we take it a step further and explore the secretome, a sophisticated set of extracellular signals released by cells, whose understanding is redefining regenerative medicine.

What is the Secretome?

The secretome encompasses all substances that a cell actively releases into its environment: proteins, RNA, lipids, vesicles, and metabolites. In mesenchymal stromal cells (MSCs) and other cell types, this “molecular orchestra” includes exosomes, microvesicles, cytokines, growth factors such as VEGF and TGF-β, and even apoptotic vesicles.

These molecules act in concert to promote tissue repair, modulate inflammation, and coordinate immune responses—all without requiring the original cells to remain in the patient’s body.

How is the Secretome Isolated and Characterized?

Its isolation is complex. The most common methods include differential ultracentrifugation, membrane filtration, and size-exclusion chromatography. Once isolated, the secretome undergoes various techniques to verify its content and activity, such as:

• Flow cytometry – to identify membrane proteins such as CD9, CD63, and CD81.

• Real-time PCR – to assess the expression of messenger RNAs or immunomodulatory microRNAs.

• Mass spectrometry – to quantify bioactive factors with nanomolar precision.

Functional assays further measure its ability to stimulate migration, proliferation, or regeneration in specific cell cultures.

Why Choose the Secretome Over Cells?

The acellular approach offers multiple advantages:

• Reduces the risk of immune rejection.

• Avoids complications associated with viable cells (tumorigenesis, incompatibility, etc.).

• Improves storage and enables standardized dosing.

Scientific and Regulatory Challenges

The potential is enormous, but the challenges are significant. The lack of standardized protocols makes study comparisons difficult. Intrinsic variability—due to cell source, donor age, or culture medium—poses barriers to industrialization. Regulatory frameworks are still under development in much of the world, with exceptions in countries like Japan and South Korea.

Commitment at Baja Regenerative

At Baja Regenerative, we implement strict molecular and functional validation protocols. Each batch of secretome is traced, analyzed, and produced under international quality standards, ensuring safe, effective, and scientifically validated products for physicians and patients.

Conclusion

The secretome is not just a promise—it is a growing reality. It represents both a conceptual and clinical leap, allowing intervention in complex biological processes through precise, targeted signals without the need for live cells.

As science advances toward safer, reproducible, and personalized therapies, the secretome is positioning itself as a key component of the regenerative future already underway.

At Baja Regenerative, we are committed to cutting-edge science with a strong clinical focus. Because the most transformative advances aren’t always visible… but they are always felt.

Figure 1. Typical composition of the secretome derived from mesenchymal stromal cells (MSCs).
Source: Adapted from Théry et al., 2018; Yáñez-Mó et al., 2015.

References

• Théry, C., Witwer, K. W., Aikawa, E., et al. (2018). Minimal information for studies of extracellular vesicles 2018 (MISEV2018). Journal of Extracellular Vesicles, 7(1), 1535750. https://doi.org/10.1080/20013078.2018.1535750
• Kalluri, R., & LeBleu, V. S. (2020). The biology, function, and biomedical applications of exosomes. Science, 367(6478), eaau6977. https://doi.org/10.1126/science.aau6977
• Yáñez-Mó, M., Siljander, P. R., Andreu, Z., et al. (2015). Biological properties of extracellular vesicles and their physiological functions. Journal of Extracellular Vesicles, 4, 27066. https://doi.org/10.3402/jev.v4.27066
• Doyle, L. M., & Wang, M. Z. (2019). Overview of Extracellular Vesicles, Their Origin, Composition, Purpose, and Methods for Exosome Isolation and Analysis. Cells, 8(7), 727. https://doi.org/10.3390/cells8070727
• Marbán, E. (2018). The Secret Life of Exosomes: What Do We Really Know About Exosome Therapeutics? Circulation Research, 123(1), 92–95. https://doi.org/10.1161/CIRCRESAHA.118.312546

Author: Jose Luis Flores Sevilla, MSc. PhD. Molecular Biomedicine.