Abstract 062: Bone Marrow-derived Mesenchymal Stromal Cells Engineered To Release Anti-fibrotic Cargo, Evoke Renoprotective Effects Against Hypertensive Chronic Kidney Disease

Abstract

Human bone marrow-derived mesenchymal stromal cells (BM-MSCs) have emerged as a promising treatment option for chronic kidney disease (CKD), based on their anti-hypertensive, immunomodulatory and tissue-reparative effects. However, the build-up of fibrosis (scar tissue) in CKD significantly impairs the viability and efficacy of implanted BM-MSCs. To address this, we previously combined the separate administration of BM-MSCs with the anti-fibrotic drug, serelaxin (RLX), which enhanced the renoprotective effects of BM-MSCs in normotensive and hypertensive models of CKD. To advance the clinical application of this combined therapy, we have now engineered BM-MSCs to express RLX and GFP (BM-MSCs-RLX+GFP) or GFP alone (BM-MSCs-GFP) using lentiviral transduction, to deliver the combined treatments via the same route simultaneously. The therapeutic effects of BM-MSCs-RLX+GFP were then investigated in a high salt (HS; 2% NaCI)-induced model of hypertension. Flow cytometry revealed a transduction efficiency of 76% and 93% at a multiplicity of infection of 1 or 2, for BM-MSCs-RLX+GFP and BM-MSCs-GFP, respectively. When cultured for 3- and 7-days in vitro , 1x10 6 BM-MSCs-RLX+GFP produced 29±3 and 31±3ng/ml of RLX, respectively. Subgroups of 10-12 week-old male Balb/C mice were subjected to HS loading for 8 weeks. During the final 2 weeks (weeks 7-8), sub-groups of mice were treated with i) RLX (0.5mg/kg/day; s.c) and BM-MSCs (RLX+BM-MSCs); ii) BM-MSCs-GFP; iii) BM-MSCs-RLX+GFP (all 1x10 6 cells/mouse; i.v); or iv) the ACE inhibitor, perindopril (2mg/kg/day, p.o). HS loading increased systolic blood pressure (SBP) to 140-145mmHg but reduced creatine clearance (23mL/24h), compared to the 115-120mmHg and 50mL/24h, respectively, in mice given normal drinking water (both p<0.05). All treatments blunted SBP to 123-130mmHg (no different to baseline levels), whilst creatinine clearance was partially restored by all cell-based treatments (to 34-40mL/24h), but not perindopril. The treatment-induced effects on renal inflammation and fibrosis are currently being evaluated and will be presented. These findings suggested that the genetic engineering of BM-MSCs that released anti-fibrotic cargo (RLX) may be a novel treatment option for hypertensive CKD.