PLacental eXpanded (PLX) cells are off-the-shelf placenta-derived mesenchymal-like adherent stromal cells that are suitable for allogeneic administration without HLA-matching due to their low immunogenicity and immune-modulatory properties.



Accumulated in-vitro and animal data strongly suggests that these cells have the capacity to release soluble biomolecules, such as cytokines,chemokines and growth factors, which act in a paracrine or endocrine manner to facilitate healing of damaged tissue. The cells secrete the therapeutic factors which in turn reach the target tissue through the blood stream and initiate the healing process.

The systemic therapeutic effect of PLX-PAD can be seen in several pre-clinical animal models. The first is the hind limb ischemia model in mice. In this model, the femoral artery of one of the limbs is ligated resulting in an ischemic damage to the limb. Post ligation, PLX-PAD cells are administered intramuscularly (IM) to the injured limb or to the contralateral healthy limb. In both treatment groups, a significant increase in blood flow of the ischemic limb is observed compared to the none-treated control mice, regardless of which limb was treated. Additionally, not only did the therapeutic effect remain the same in terms of blood flow measurements, but also the rejuvenation of ischemic tissue was better. Further support to the systemic effect can be seen in the Preeclampsia mouse model, where the PLX cells demonstrated beneficial systemic effects in pregnant mice with the established disease. In these female mice, IM administration of PLX-PAD cells resulted in reduction of the high blood pressure and lowering urinary protein, which are the main characteristics of preeclampsia.

Animal studies of cell delivery and fate have clearly demonstrated that when PLX Cells are injected IM they do not migrate and remain within the injected muscle only for a duration of a few weeks.

This therapeutic systemic effect of PLX cells and their ability to “sense” environmental stress is demonstrated by their local IM administration to mice induced to display acute radiation syndrome (ARS) following total body irradiation. PLX-RAD, Pluristem’s second product, injected IM, was able to mitigate the radiation induced bone marrow damage as evident by an increase in survival and body weight of the irradiated mice. Additionally, these treated mice demonstrated an improvement in all three blood lineages that includes red cells, while cells and platelets as well as nucleated bone marrow cell counts. The plasma of the experimental animals was collected and studied for the presence of specific human proteins. Pluristem found that human cytokines were transiently elevated in the plasma of PLX-RAD-treated irradiated mice as compared to PLX-RAD-treated non-irradiated mice were these factors were absent.

All of the above data, emphasize that the cells are able to alter their secretome following the recognition of environmental changes and the ability of these secreted factors to reach the blood stream to be delivered to their site of action''