Involvement of the Mitochondrial Pathway in Cold Storage and Rewarming-Associated Apoptosis of Human Renal Proximal Tubular Cells

Abstract

The cellular and molecular mechanisms of cold storage‐ATN are not well characterized. In our earlier studies, cold storage caused necrosis of human proximal tubular epithelial (RPTE) cells, whereas apoptosis was prominent during rewarming. An intriguing finding was the pronounced swelling of the mitochondria in the cold, which promoted us to further characterize its role in rewarming‐associated apoptosis. Human proximal tubular epithelial cells were cold stored in University of Wisconsin (UW) solution for 48 h followed by 24 h of rewarming in regular cell culture medium. During the cold storage, there was no significant change in the Bcl‐2 to Bax protein ratio, mitochondrial location of cytochrome C or caspse‐3 activity. However, during rewarming, the Bcl‐2 to Bax ratio increased, cytochrome C was translocated to cytosol, and caspase‐3 was activated: events and timing were consistent with the occurrence of apoptosis during rewarming. In a time‐course experiment, mitochondrial swelling was discernable by electron microscopy as early as at 2 h. Cold storage of isolated‐mitochondria for 2 h was attended by an increase in the opening of the permeability transition pores (PTP), suggesting PTP opening as an early mechanism for mitochondrial swelling. Addition of antioxidants (deferoxamine or 2‐methyaminochroman) to the storage solution suppressed mitochondrial pore opening and swelling, Bcl‐2 to Bax ratio increase, cytochrome C translocation, caspase‐3 activation as well as rewarming‐induced apoptosis. Our data demonstrate for the first time that apoptosis following cold storage and rewarming of human renal tubular cells is accompanied by specific mitochondrial events, and that these events and apoptosis can be suppressed by adding antioxidants to the cold storage solution.

Cold ischemic injury of transplanted kidneys: new insights from experimental studies

“…The PTP, formed from mitochondrial membrane-bound adenine nucleotide translocase and cyclophilin D, opens with calcium and free radicals and closes with CsA (10,17,20). In our study, cold storage of human renal tubular cells was attended by mitochondrial PTP opening and mitochondrial swelling (62). Moreover, cold-induced mitochondrial swelling was attended by a number of key proapoptotic events such as cytochrome c translocation and Bax-to-Bcl-2 ratio increase (Fig.…”

“…1) (65). This prompted us to study the role of the mitochondrial apoptotic pathway in the setting of cold ischemic renal injury (62,65).…”

“…In a (62). Cold (top) via calcium and free radicals opens permeability transition pore (PTP), causing marked mitochondrial swelling, which, in turn, triggers key apoptotic events and sets the stage for apoptosis during rewarming (bottom).…”

Serum- and albumin-free cryopreservation of endothelial monolayers with a new solution

“…14,35,36 Loss of mitochondrial membrane potential was also described after cryopreservation, for example in sperm, 37–39 mouse embryos, 40 muscle, 41,42 hepatocytes 43 and in isolated mitochondria. 44,45 Also, ultrastructural changes in mitochondria, like mitochondrial swelling and rupture have been described to occur in endothelial cells after vascular cryopreservation, 46,47 however, little is known about mitochondrial membrane potential in this cell type.…”

Trametes robiniophila may induce apoptosis and inhibit MMPs expression in the human gastric carcinoma cell line MKN-45

“…Considering the potential toxic effect of high doses of Trametes robiniophila on normal cells, 5 mg/ml should be taken as a reference for future clinical application. Generally, apoptosis can be classified into two types: Apoptotic process mediated by the mitochondrial pathway and apoptotic process mediated by a membrane receptor signaling pathway (23). Caspase-3 is one of the key apoptosis executors, since the majority of factors that trigger apoptosis ultimately lead to apoptosis through the caspase-3-mediated signaling pathway (24,25).…”