LDL-Apheresis for FSGS CardioRenal Outcomes

Focal segmental glomerulosclerosis (FSGS) is the most common cause of end-stage renal disease (ESRD) in adolescents. The refractory nature of FSGS and a more than 30% recurrence rate after kidney transplantation renders treatment of FSGS one of the most difficult challenges in pediatric nephrology. A significant knowledge gap in understanding the mechanism of FSGS treatment resistance and progression hampers development of successful treatment strategies. Beneficial effect of removal of low-density lipoproteins by LDL-apheresis indicates that lipids contribute to progression in FSGS. We have previously reported increased urinary fatty acids (FA) and lysophosphatidylcholines (LPC) levels with non-targeted urinary lipidomic analysis in children with FSGS. Unregulated phospholipase A2(PLA2) activity causes an increase in intracellular concentrations of free FA and LPC altering plasma membrane and mitochondrial permeability. Lipoprotein associated PLA2 is a biomarker involved in oxidative modification of LDL by hydrolyzing oxidative lysophosphatidylcholines (LPC) and oxidized free fatty acids (FFA) both of which are proinflammatory and atherogenic. Lp-PLA2 is efficiently removed by LDL-apheresis. The investigators hypothesize that LDL-apheresis ameliorates cellular injury and vascular changes by removing circulating Lp-PLA2, oxidized LDL, LPC, FA and cytokines in FSGS. In this proposal, the hypothesis that removal of Lp-PLA2 and lipid metabolites by LDL-apheresis ameliorates proteinuria and cardiovascular comorbidities will be tested. Patients with FSGS and FSGS recurrence after kidney transplantation receiving LDL-apheresis as part of standard of care will be enrolled to the study. Investigators will monitor pre-and post serum and effluent concentrations of LPC, free FA, Lp-PLA2, oxidized LDL, fasting lipid profile, IL-6, TNF-α, and IL-1β of patients undergoing LDL-apheresis. The impact of LDL-apheresis on cardiovascular and clinical comorbidities by monitoring degree of proteinuria, blood pressures and arterial stiffness index will also be investigated. The investigators propose that LDL-apheresis as a conjunct therapy to standard treatment regimens is an efficient way to ameliorate progression prevent comorbidities such as systemic inflammation and lipid induced vascular changes thus progression in FSGS. Furthermore, removal of Lp-PLA2 and other lipids by LDL-apheresis can limit the direct toxicity caused by lipid metabolites to podocytes and proximal tubule epithelial cells. The investigators believe that this proposal will enhance understanding of lipid-mediated progression in FSGS and will delineate the role of LDL-apheresis as part of established treatment in treatment of FSGS.