Mesenchymal Stromal Cell Bioreactor for Ex Vivo Reprogramming of Human Immune Cells.

Bone marrow mesenchymal stromal cells (MSCs) have been studied for decades as potent immunomodulators. Clinically, they have shown some promise but with limited success. Here, we report the ability of a scalable hollow fiber bioreactor to effectively maintain ideal MSC function as a single population while also being able to impart an immunoregulatory effect when cultured in tandem with an inflamed lymphocyte population. MSCs were seeded on the extraluminal side of hollow fibers within a bioreactor where they indirectly interact with immune cells flowing within the lumen of the fibers. MSCs showed a stable and predictable metabolite and secreted factor profile during several days of perfusion culture. Exposure of bioreactor-seeded MSCs to inflammatory stimuli reproducibly switched MSC secreted factor profiles and altered microvesicle composition. Furthermore, circulating, activated human peripheral blood mononuclear cells (PBMCs) were suppressed by MSC bioreactor culture confirmed by a durable change in their immunophenotype and function. This platform was useful to study a model of immobilized MSCs and circulating immune cells and showed that monocytes play an important role in MSC driven immunomodulation. This coculture technology can have broad implications for use in studying MSC-immune interactions under flow conditions as well as in the generation of ex vivo derived immune cellular therapeutics.

Extracorporeal Stromal Cell Therapy for Subjects With Dialysis-Dependent Acute Kidney Injury.

INTRODUCTION: The pathophysiology of acute kidney injury (AKI) involves damage to renal epithelial cells, podocytes, and vascular beds that manifests into a deranged, self-perpetuating immune response and peripheral organ dysfunction. Such an injury pattern requires a multifaceted therapeutic to alter the wound healing response systemically. Mesenchymal stromal cells (MSCs) are a unique source of secreted factors that can modulate an inflammatory response to acute organ injury and enhance the repair of injured tissue at the parenchymal and endothelial levels. This phase Ib/IIa clinical trial evaluates SBI-101, a combination product that administers MSCs extracorporeally to overcome pharmacokinetic barriers of MSC transplantation. SBI-101 contains allogeneic human MSCs inoculated into a hollow-fiber hemofilter for the treatment of patients with severe AKI who are receiving continuous renal replacement therapy (CRRT). SBI-101 therapy is designed to reprogram the molecular and cellular components of blood in patients with severe organ injury. METHODS: This study is a prospective, multicenter, randomized, double-blind, sham-controlled, study of subjects with a clinical diagnosis of AKI who are receiving CRRT. Up to 32 subjects may be enrolled to provide 24 evaluable subjects (as a per protocol population). Subjects will receive CRRT in tandem with a sham control (0 MSCs), or the low- (250 × 106 MSCs) or high-dose (750 × 106 MSCs) SBI-101 therapeutic. RESULTS: The study will measure dose-dependent safety, renal efficacy, and exploratory biomarkers to characterize the pharmacokinetics and pharmacodynamics of SBI-101 in treated subjects. CONCLUSION: This first-in-human clinical trial will evaluate the safety and tolerability of SBI-101 in patients with AKI who require CRRT.