Mitochondria Transplantation Mitigates Damage in an In Vitro Model of Renal Tubular Injury and in an Ex Vivo Model of DCD Renal Transplantation

Abstract

Objectives: To test whether mitochondrial transplantation (MITO) mitigates damage in two models of acute kidney injury (AKI). Summary Background Data: MITO is a process where exogenous isolated mitochondria are taken up by cells. As virtually any morbid clinical condition is characterized by mitochondrial distress, MITO may find a role as a treatment modality in numerous clinical scenarios including AKI. Methods: For the in vitro experiments, human proximal tubular cells were damaged and then treated with mitochondria or placebo. For the ex vivo experiments, we developed a non-survival ex vivo porcine model mimicking the donation after cardiac death (DCD) renal transplantation scenario. One kidney was treated with mitochondria, while the mate organ received placebo, before being perfused at room temperature for 24 hours. Perfusate samples were collected at different time points and analyzed with Raman spectroscopy. Biopsies taken at baseline and 24 hours were analyzed with standard pathology, immunohistochemistry and RNA sequencing analysis. Results: In vitro, cells treated with MITO showed higher proliferative capacity and ATP production, preservation of physiological polarization of the organelles and lower toxicity and reactive oxygen species production. Ex vivo, kidneys treated with MITO shed fewer molecular species, indicating stability. In these kidneys, pathology showed less damage while RNAseq analysis showed modulation of genes and pathways most consistent with mitochondrial biogenesis and energy metabolism and downregulation of genes involved in neutrophil recruitment, including IL1A, CXCL8, and PIK3R1. Conclusions: MITO mitigates AKI both in vitro and ex vivo.

Cellular and molecular mechanisms of cell damage and cell death in ischemia–reperfusion injury in organ transplantation

“…Mitochondrial transplantation is a process where exogenous isolated functional mitochondria are taken up by damaged cells to recover dysfunctional mitochondria. In an in vitro model of renal tubular injury, for example, treatment of damaged human proximal tubular cells with mitochondria enhanced proliferative capacity and significantly increased ATP production, along with preserved physiological polarization, and markedly reduced toxicity and ROS production compared to control cells that were treated with placebo [ 128 ]. The authors conducted a separate experiment using a non-survival ex vivo model of donation-after-cardiac death kidney transplantation, in which donor kidneys were treated with mitochondria prior to perfusion at room temperature for 24 h. Compared to placebo-treated control kidneys, Raman spectroscopy of perfusate samples revealed fewer molecular species in mitochondria-treated kidneys, which indicates stability.…”

“…The authors conducted a separate experiment using a non-survival ex vivo model of donation-after-cardiac death kidney transplantation, in which donor kidneys were treated with mitochondria prior to perfusion at room temperature for 24 h. Compared to placebo-treated control kidneys, Raman spectroscopy of perfusate samples revealed fewer molecular species in mitochondria-treated kidneys, which indicates stability. Additionally, mitochondrial transplantation resulted in less kidney damage while analysis of RNA sequencing showed increased mitochondrial bioenergetics and downregulated expression of pro-inflammatory genes [ 128 ]. Also, supplementation of organ preservation solution with mitochondria-targeted AP39 and sodium thiosulfate at 21ºC and 4ºC for 4 and 24 h respectively and reperfused for 4 h prevented apoptosis, protected against IRI and improved renal graft function in ex viv o porcine and rat models of kidney transplantation [ 129 , 130 ].…”

Mitochondrial transplantation and transfer: The promising method for diseases

“…Mitochondrial transplantation in vitro demonstrated increased proliferative capacity, ATP generation, and decreased ROS production in a renal transplantation model. Ex vivo studies revealed decreased kidney damage and RNAseq analysis found downregulation of genes such IL1A, CXCL8, and PIK3R1 that are involved in neutrophil recruitment as well as modification of genes most associated with mitochondrial biogenesis and energy metabolism ( Rossi et al, 2023 ). As shown in preclinical studies, mitochondrial transplantation can improve the ability of renal cells to repair and proliferate while also reducing kidney damage and restoring renal function.…”