Serum-free derivation
Removing serum eliminates a major undefined variable from the protocol. We reported generation of MSCs from hESCs in a completely serum-free condition in International Journal of Biological Sciences, 2018 (14(13):1901–1909).
Platform science
The T-MSC platform
Directed differentiation of human embryonic stem cells into mesenchymal stem cells through a trophoblast-like intermediate stage — how it works, what the resulting cells are, and how we know.
Foundations
Why the intermediate stage matters
Mesenchymal stem cells have been studied as an immunomodulatory therapy for decades, almost always sourced from adult tissue — bone marrow, adipose tissue, umbilical cord. That sourcing imposes a ceiling on the science: every preparation carries the donor's age and genetic background, expansion capacity is finite, and batch-to-batch variability confounds the interpretation of results.
Our laboratory takes a different starting point. Human embryonic stem cells self-renew effectively indefinitely and can be characterised once, deeply. The scientific problem then becomes the differentiation route. We direct hESCs to a trophoblast-like intermediate stage and from there to mesenchymal stem cells, which we designate T-MSCs. This strategy is designed to recapitulate aspects of placental MSC development. Importantly, the trophoblast-like stage is not merely a transitional step; it is the critical developmental checkpoint that shapes the phenotype and functional properties of the resulting cells.
Derivation route
Three defined stages
hESCWell-characterised human embryonic stem cell lines; effectively unlimited self-renewal
Trophoblast-like intermediateThe defining step of the platform — a directed intermediate stage that sets the resulting phenotype
T-MSCMesenchymal stem cells of high purity and batch-to-batch consistency, independent of tissue donors
The differentiation route was first reported in Stem Cells in 2016 (Wang X, et al., 34(2):380–391), building on earlier work from the same investigators showing that BMP4 initiates human embryonic stem cell differentiation to trophoblast (Nature Biotechnology, 2002). Dr Xiaofang Wang and Professor Ren-He Xu are the inventors of the T-MSC differentiation technology.
Characterisation
Measured properties of T-MSCs
The comparisons below are drawn from ImStem's preclinical studies of T-MSCs against mesenchymal stem cells derived from adult tissue.
| Property | Observation |
|---|---|
| Cell origin | Derived from allogeneic pluripotent human embryonic stem cells rather than from tissue donors, removing donor-to-donor variance from the preparation. |
| Proliferation | The source cells expand in vitro effectively indefinitely, permitting scale-up without the replicative ceiling of adult MSCs. |
| Consistency | Shorter differentiation time and a directed route yield homogeneous preparations with reduced batch-to-batch variation. |
| Immunogenicity | Low measured propensity to induce an immune response, with markedly lower MHC class II antigen expression than bone marrow-derived MSCs. |
| Anti-inflammatory cytokines | Consistent secretion of PD-L1, IL-10 and TGF-β — approximately two- to five-fold that of adult MSCs in our studies. |
| Pro-inflammatory cytokines | Low secretion of pro-inflammatory mediators. Bone marrow MSCs express high levels of IL-6, which can aggravate autoimmune disease. |
| Blood–brain barrier | Evidence of activity at the blood–brain barrier: hES-derived MSCs corrected TNF-α-mediated alterations in a defined in vitro BBB model. |
| Developmental potency | Following blastocyst injection, injected cells contributed to skeletal, dermal and extraembryonic tissues in chimeric mouse embryos. |
Note. These conclusions derive from preclinical studies conducted by ImStem and
its scientific advisors comparing T-MSCs with MSCs derived from adult tissues. They describe
laboratory and animal-model findings, not yet demonstrated clinical benefit in patients.
Manufacturing science
Reproducibility as a research problem
A differentiation route that cannot be reproduced at scale is not a usable result. Several strands of the laboratory's work address this directly.
Scalable 3D culture
Moving derivation into three-dimensional spheroid culture supports scale-up (Int J Biol Sci, 2018, 14(10):1196–1210), and spheroid formation itself changes cell behaviour in ways relevant to potency and delivery.
Ambient-temperature preservation
Spheroidal formation preserves human stem cells for prolonged periods under ambient conditions (Biomaterials, 2017, 133:275–286), which bears directly on how far a cell product can travel from where it is made.
Engineering persistence
Infused MSCs are cleared quickly by host innate immunity. We reported engineering of human MSCs resistant to multiple natural killer cell subtypes (Int J Biol Sci, 2022, 18(1):426–440), addressing a central limitation of the whole field.
Intellectual property
Platform patents granted
The composition of matter covering T-MSCs — mesenchymal-like stem cells derived from human embryonic stem cells, methods and uses thereof, invented by Xiaofang Wang and Ren-He Xu — has been granted in six jurisdictions. Grant dates below are as recorded in the published patent documents.
| Jurisdiction | Number | Granted |
|---|---|---|
| United States | US 9,725,698 B2 | 8 August 2017 |
| China | CN 104487568 B | 15 August 2017 |
| United States | US 9,745,551 B2 | 29 August 2017 |
| Australia | AU 2013290146 B2 | 18 January 2018 |
| Japan | JP 6277187 B2 | 7 February 2018 |
| European Union | EP 2872619 B1 | 14 February 2018 |
| China | CN 104471059 B | 17 April 2018 |
| United States | US 10,226,488 B2 | 12 March 2019 |
| United States | US 10,557,122 B2 | 11 February 2020 |
| United States | US 10,842,826 B2 | 24 November 2020 |
| Canada | CA 2876512 C | 13 December 2022 |
Related granted patents
The earlier hESC culture and trophoblast patents on which the platform rests, and later grants covering derivation, preservation and application of the cells.
| Subject | Inventors | Number | Granted |
|---|---|---|---|
| Method for generating primate trophoblasts | Xu R-H., Thomson J.A. | US 7,390,657 B2 | 24 June 2008 |
| Cultivation of primate embryonic stem cells | Thomson J.A., Levenstein M., Xu R-H. | US 7,439,064 B2 | 21 October 2008 |
| Feeder-independent extended culture of embryonic stem cells | Xu R-H., Thomson J.A. | US 7,514,260 B2 | 7 April 2009 |
| Storage and transport of stem cells at ambient temperature, and the matrix used for it | Xu R-H., Jiang B., Yan L. | CN 107306936 B | 2 March 2021 |
| Corneal epithelial cells and corneal scaffold, their preparation and applications | Xu R-H., Yang J., Zheng D., Park J.W. | CN 110468094 B | 13 April 2021 |
| Differentiation of pluripotent stem cells into mesenchymal stem cells under 3D spheroidal culture conditions | Xu R-H., Jiang B., Yan L. | US 11,098,281 B2 | 24 August 2021 |
| A stem cell ointment for treating skin injuries, and its preparation method | Wang X., Jiang B., Xu R-H. | CN 108938669 B | 8 April 2022 |
| Application of spherical substances in the preparation of intravenous injections | Xu R-H., Si W., Yang C., Yan Y. | CN 115590883 B | 17 July 2026 |
A Hong Kong application in the composition of matter family (HK 1208055 A1) remains pending. ImStem holds roughly 20 patents globally across the platform and its applications.