Collagen-dependent platelet dysfunction and its relevance to either mitochondrial ROS or cytosolic superoxide generation: a question about the quality and functional competence of long-stored platelets

Abstract

Background: Upon vascular damage, the exposed subendothelial matrix recruits circulating platelets to site of injury while inducing their firm adhesion mainly via GPVI-collagen interaction. GPVI also supports aggregatory and pro-coagulant functions in arterial shear rate even on the matrix other than collagen. Reactive oxygen species (ROS) modulate these stages of thrombosis; however augmented oxidant stress also disturbs platelet functions. Storeddependent platelet lesion is associated with the increasing levels of ROS. Whether ROS accumulation is also relevant to collagen-dependent platelet dysfunction is the main interest of this study. Methods: Fresh PRP-PCs (platelet concentrates) were either stimulated with potent ROS-inducers PMA and CCCP or stored for 5 days. Intra-platelet superoxide (O 2 −−) or mitochondrial-ROS and GPVI expression were detected by flowcytometery. GPVI shedding, platelet aggregation and spreading/adhesion to collagen were analyzed by western blot, aggregometry and fluorescence-microscopy, respectively. Results: Mitochondrial-ROS levels in 5 days-stored PCs were comparable to those induced by mitochondrial uncoupler, CCCP while O 2 −− generations were higher than those achieved by PMA. Shedding levels in 5 daysstored PCs were higher than those induced by these potent stimuli. GPVI expressions were reduced comparably in CCCP treated and 5 days-stored PCs. Platelet adhesion was also diminished during storage while demonstrating significant reverse correlation with GPVI shedding. However, only firm adhesion (indicated by platelets spreading or adhesion surface area) was relevant to GPVI expression. Platelet adhesion and aggregation also showed reverse correlations with both O2 −− and mitochondrial-ROS formations; nonetheless mitochondrial-ROS was only relevant to firm adhesion.

Autophagy Ameliorates Reactive Oxygen Species-Induced Platelet Storage Lesions

“…ROS in platelets may be derived from NOX 1 and NOX 2 activation [ 26 ], which are positive regulators during agonist-induced platelet activation. On the other hand, ROS production during platelet storage has been described previously to cause PSLs, such as platelet receptor loss, granule release, and viability impairment [ 20 , 31 , 32 ]. Endogenous ROS produced during platelet storage could be a by-product of respiration chain [ 19 ], and accumulated ROS in stored platelets disturbs mitochondrial membrane potential, blocks ATP/ADP exchange translocase at the mitochondrial surface, then subsequently leads to apoptosis [ 33 ].…”

Platelets Facilitate Wound Healing by Mitochondrial Transfer and Reducing Oxidative Stress in Endothelial Cells

“…Several recent studies have showed that PCs could alleviate oxidative stress, including in skeletal muscle contusion, gingival fibroblasts, and human spermatozoa, and ameliorate nephrotoxicity [ 19 ]. At the same time, platelets and their mitochondria may also be the sources of ROS [ 20 – 22 ]. Considering the role of mitochondrial transfer in reducing cell injury, it is worth considering whether the mitochondria released by platelets play a role in the process of platelet concentrates reducing oxidative stress.…”

Liposomal Resveratrol Alleviates Platelet Storage Lesion via Antioxidation and the Physical Buffering Effect

“…9,10 ROS are generated by NADPH oxidase, p66Shc oxidase, COX oxidase, and the mitochondrial respiratory chain. 11 Increased ROS levels can lead to platelet apoptosis, 12 activation, 13 loss of platelet adhesiveness and aggregation to reactive matrixes, 14 and a decline in platelet quality. 15 Notably, the concentrated platelets stored in an incubator and agitator undergo deleterious changes due to the physical interaction among the platelets and between them with the environment.…”

“…Factors that initiate PSL include storage duration and temperature, storage medium, container, and mode of agitation. , Both physical and chemical stimuli can affect platelet state, with excessive reactive oxygen species (ROS) accumulation being a primary cause for PSL. , ROS are generated by NADPH oxidase, p66Shc oxidase, COX oxidase, and the mitochondrial respiratory chain . Increased ROS levels can lead to platelet apoptosis, activation, loss of platelet adhesiveness and aggregation to reactive matrixes, and a decline in platelet quality . Notably, the concentrated platelets stored in an incubator and agitator undergo deleterious changes due to the physical interaction among the platelets and between them with the environment …”