Bioregulators of stem and progenitor cells in preservation solution reduce cold ischemia-reperfusion injury of isolated rat livers

The effects of bioregulators of stem and progenitor cells (BSPC) of fetal tissue cytosol on rat liver during 24h hypothermic storage (HS) and following normothermic reperfusion (NR) were investigated. It was shown that BSPC presence in the preservation medium stabilized pro-oxidant-antioxidant balance impaired in liver after HS and NR, prevented the uncoupling of mitochondrial oxidative phosphorylation and ATP level decline. These consequences led to significant improvement of hepatic morphological integrity and functional state. Powerful protective effect of BSPC on liver at sub-zero temperatures can serve as basis for new approaches to extend safe time for organ preservation and foster understanding of pathways of stem and progenitor cell paracrine action. © 2016 BioFactors, 42(3):287-295, 2016.

Capacity of bioregulators of stem and progenitor cells to strongly affect liver redox-dependent processes

Abstract Effects of stem and progenitor cells or their compounds on recipient cells are investigated intensively today. In spite of this, their ability to interact with native cells and the final targets affected by them, particularly biochemical parameters that characterize cell redox-dependent processes, remain little studied. We have studied how bioregulators of stem and progenitor cells affect these processes in freshly isolated liver after animal pretreatment in vivo. Cytosol of human fetal mesenchymal-mesodermal tissues (8-10 weeks gestation) was administered intravenously; the control group was treated with Hanks' solution. After 4 hr, rats were sacrificed and their livers were isolated. To evaluate liver redox-dependent state, mitochondrial respiratory activity and nitroxyl radical and Alamar Blue™ reduction rates, mitochondrial and cytosolic glycerol kinase and nicotinamide adenine dinucleotide (NADH)-dependent malate dehydrogenase activities were studied. The results obtained demonstrate that bioregulators strongly affect liver redox-dependent processes, increasing mitochondrial respiration in state III and spin probe reduction rate and enhancing Alamar Blue™ reduction by glycolytic and nonglycolytic postmitochondrial enzymes. In addition, mitochondrial glycerol kinase and both isoforms of NADH-dependent malate dehydrogenase were inhibited. These data bring us closer to understanding stem and progenitor cell effects via directed regulation of metabolic redox-dependent processes.

[Influence of mitochondrial antioxidant 10-(6-plastoquinonyl)decyltriphenylphosphonium on peroxidation process intensity and respiratory activity of rat isolated liver after hypothermic storage]

The influence of mitochondria-targeted antioxidant 10-(6-plastoquinonyl)decyltriphenylphosphonium (SkQ,) different concentrations on respiratory parameters and lipid peroxidation process intensity in the rat liver after hypothermic storage was investigated. It was shown that cold storage of isolated liver during 18 h results in accumulation of TBA-active products, increase of intensity of Fe(2+)-ascorbate induced lipid peroxidation and depression of mitochondria functional activity. SkQ1 inhibits activation of free radical processes in a dose-dependent manner and it has a positive influence on energetic coupling in mitochondria.

Mitochondrial function after liver preservation in high or low ionic-strength solutions: a comparison between UW-based and sucrose-based solution

In this study we evaluated mitochondrial function after liver cold storage and normothermic reperfusion. The preservation solutions were: modified University of Wisconsin (mod UW) and sucrose-based solution (SBS). After cold preservation liver was re-perfused for 1 hour in vitro with Krebs-Ringer buffer at 37 degree C. Samples of tissue were taken for ATP determination. Mitochondrial respiratory parameters, succinate oxidase complex activity, mitochondrial H+- ATPase and intramitochondrial potassium concentration were assayed. It was shown, that brief (1 hour) cold storage and subsequent normothermic reperfusion revealed no difference in liver ATP content between mod UW and SBS groups but resulted in a gradual decrease of 50 percent after 24-hour storage and reperfusion. Mitochondrial potassium ion concentration increased by 40 percent after 1-hour cold storage in the mod UW as compared to control (P value less than 0.05) and SBS. After brief cold storage ADP and uncoupler-stimulated respiration increased by 120 percent in SBS group, unlike mod UW, when succinate was used as substrate, and was more pronounced after 24 hour. Succinate oxidase complex activity did not change over either cold storage or warm reperfusion. Mitochondrial H+-ATPase activities in SBS and mod UW did not differ and both were inhibited after 24-hour cold storage. Our data demonstrate that low ionic strength preservation solution can substantially modulate mitochondrial energy turnover due to substrate oxidation increase. Many of the changes in mitochondrial function follow brief exposure to low temperatures.

[Effect of 2,4-dinitrophenol on the rat liver respiratory activity and ATP content after hypothermic storage and following reperfusion]

The influence of oxidative phosphorylation uncoupler 2,4-dinitrophenol (DNP) presence in preserving solution on the rat liver respiratory activity and ATP content after 18 h of hypothermic storage (HS) and following normothermic reperfusion (NR) was investigated. DNP presence on the HS stage led to decrease of ATP level as compared with the control. After DNP removal during NR the gradual recovery of oxidative phosphorylation coupling occurred. This fact resulted in improvement of mitochondrial functional state (V4 respiration rate decrease, respiratory control and ATP level increase).

[The cryopreservation of isolated liver cells]

Recent literature data on cryopreservation of isolated hepatocytes are summarized. The hepatocytes are considered to constitute a promising system for investigation of liver metabolic peculiarities as well as for elucidating mechanisms of low temperature effects on biological systems.