Science

In the last 10 years, a new technology has emerged: the formation of human ossicles (hOss) in mice. These ossicles are miniaturized human bone organs, composed of human skeletal and blood cells. They allow rebuilding the human bone marrow environment with healthy cells in an “in vivo” setting, usually humanized mice. These hOss are thus promising models to both study human hematopoiesis (formation of blood cells) and also test drugs in vivo before entering clinical trials.

OssiGel

Our team has developed a unique in vivo human bone marrow organoid model, defined as “humanized ossicles” (hOss). The formation of hOss is performed through the subcutaneous injection of the OssiGel technology in humanized mice (immunocompromised), mixed with human mesenchymal stromal cells (MSCs) isolated from the patient of interest. After a few weeks in vivo, the gel-MSCs mixture gets extensively remodeled leading to the establishment of a personalized hOss (mini-bones).

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The product, OssiGel, consists of a molecularly customized extracellular matrix produced by a dedicated cell line, and transformed into a gel-like material. This gel contains all the necessary signals to instruct the formation of a bone marrow like ossicle in vivo. The hOss provide the necessary environment for the engraftment of different cancer cells (e.g prostate cancer), allowing the testing of new candidate substances for cancer treatment.

Our model is substantially more user-friendly and reproducible than previous protocols (over 95% reproducibility), and, as such, it can generate significant advancements in oncology. Certain leukemia subtypes only engraft in hOss or otherwise require lengthy in vivo permanence (i.e. > 1 year to grow), thus making hOss the best available method to study them and test treatments. Moreover, several primary solid tumors often metastasize to bones (e.g. breast, prostate, lung, neuroblastoma) can also be studied in hOss compared to non-existent or poorly performing humanized models, generating even higher clinical potential for our model.