Research Information System
ISSCR 2022 Annual Meeting, California, United States Of America, 15 - 18 June 2022, pp.345
Mesenchymal stem cells (MSC) and MSC exosomes (MSC-Exos) are strong therapeutic candidates for ischemic acute kidney injury (AKI) but their safety and efficacy remain ambiguous. MSC-Exos gave contradicting outputs when applied to proximal tubule (PT) epithelial monolayers and murine surgical ischemia models to test their potential for ischemic AKI. We hypothesized that therapeutic potential of allogeneic human bone marrow mesenchymal stem cell exosomes (hBMMSC-Exos) may be assessed on microfluidic-based 3D culture platform to quantify functional effects of the hBMMSC-Exos on acute hypoxic tubular injury. In brief, hBMMSC-Exos were isolated with ultracentrifugation, characterized by TEM and BCA assay. Real-time impedance-based cell proliferation analysis (RTCA) determined the treatment window for the hBMMSC-Exos on HK-2 cells in hypoxic conditions. The acute hypoxic tubular injury was modelled on a microfluidic-based 3D culture platform under 1% O2 for 48 hours. The proliferation of PT cells was assessed with WST-1 assay. 20 kDa and 155 kDa probes were used to assess and quantify epithelial barrier integrity. hBMMSC-Exos were characterized with high protein content (3694 ± 439.2 µg/ml) by BCA and typical spherical vesicles with bilayer membrane under TEM with mean dimensions of 52.18 µm and 51.27 µm. We described the effective treatment window of hBMMSC-Exos on PT cells under normoxia as 26 hours after application according to the changes in ED50 in RTCA. ED50 of hBMMSC-Exos under hypoxia was detected as 172.582 mg/ ml at 26th hour. hBMMSC-Exos alleviated cell proliferation after 24 hours (p< 0.0001) after hypoxic tubular injury. Barrier integrity assay revealed that hBMMSC-Exos ameliorated epithelial barrier integrity after injury for both 20 kDa (p=0.0004) and 155 kDa (p<0.0001) dextran probes. In this study, the authors described a series of potency assays demonstrating real-time proliferative ED50 of allogeneic hBMMSC-Exos on PT on a chip, and validating the cellular alleviating effect of hBMMSC-Exos on an optimized 3D microfluidic platform. The real time platform presents a powerful tool for future precision medicine works with hBMMSC-Exos on AKI in terms of patient specific personalized efficacy and treatment window to ease the translation of the results obtained to nephrology clinic.
Funding Source: Hacettepe University Research Fund financially supported this work (TSA-2020-18383).
Keywords: BMMSC Exosomes, Proximal Tubule on a Chip, Acute Kidney Injury