Obj. 1: we designed and built a transcutaneous diagnostic device capable of measuring three tracers simultaneously. This device was successfully tested in phantoms and other surrogates. Final tests are being finalised to enable a patent application. We have also developed a range of dyes suitable for determining glomerular filtration and tubular excretion/re-absorption using this device and other tools such as multispectral optoacoustic tomography (MSOT). A biomarker panel, which can inform renal function, was established based on the measurement of 7 protein bound uremic toxins in tissues (i.e. renal tissue, blood, urine).
Obj. 2: we explored a range of imaging tools to determine the biodistribution and fate of MSC therapies and renal function/structure in the course of IRI. In animal models, genetic reporters in combination with BLI was the most appropriate modality to track biodistribution and fate of the MSCs. Probe-based imaging provides higher spatial resolution to determine intra-organ distribution of MSCs, which we have shown via MRI and MSOT. These modalities, as well as ultra-fast ultrasound, were also able to inform kidney function/structure. MSOT, with dyes produced in our network, provided a safe, fast, radiation-free method to measure single kidney GFR in mice.
At the doses used, the safety profile of the MSCs was good. MSCs tended to die shortly after administration and we believe that the risks they pose are minimal. Post-mortem assessment showed their accumulation in the pulmonary microvasculature immediately after administration, and death in subsequent days. We did not observe significant efficacy in our animal model of renal IRI with any type of MSC, apart from a reduced serum creatinine following administration of bone marrow-derived MSCs. Our results do not support the translation of any of the MSC sources to clinical trials for the treatment of renal IRI at the present time.
Obj. 3: we established assays to characterise MSCs at multiple levels from purity to efficacy. Head-to-head comparison of different MSCs and their bioproducts shows that different MSC types have individual properties, suggesting that each of them might have specific benefits depending on the therapeutic setting.
Our potency assays involving an in-vitro model of IRI suggest that MSC bioproducts such as conditioned medium (CM) suffice to induce a recovery of renal cells that is comparable to, and in some cases, better than reperfusion, depending on the specific assay. This provides a different avenue as to what product to use as a therapy. Our matrix of potency assays does not suggest a specific regenerative role for EVs, with CM sufficing to induce beneficial effects.
MSC pulmonary entrapment and the rapid death soon after administration suggests that in vivo, any therapeutic mechanisms are likely due to paracrine factors derived from the cells. Our in vitro assays suggested an immunomodulatory capacity of MSCs and at a systemic level, MSCs triggered an innate immune response by the host and we found that pro-inflammatory molecules were reduced in the serum of animals that received MSCs, supporting their immunomodulatory MoA.
Exploitation and dissemination is ongoing, with 1 patent application and 1 in preparation. Over 50 scientific publications are expected, of which 32 have already been published. Our data was presented in over 30 conferences and workshops.
