Resveratrol Prevents Warm Ischemia–Reperfusion Injury in Liver Grafts From Non–Heart-Beating Donor Rats

Combating Ischemia-Reperfusion Injury with Micronutrients and Natural Compounds during Solid Organ Transplantation: Data of Clinical Trials and Lessons of Preclinical Findings

Although extended donor criteria grafts bear a higher risk of complications such as graft dysfunction, the exceeding demand requires to extent the pool of potential donors. The risk of complications is highly associated with ischemia-reperfusion injury, a condition characterized by high loads of oxidative stress exceeding antioxidative defense mechanisms. The antioxidative properties, along with other beneficial effects like anti-inflammatory, antiapoptotic or antiarrhythmic effects of several micronutrients and natural compounds, have recently emerged increasing research interest resulting in various preclinical and clinical studies. Preclinical studies reported about ameliorated oxidative stress and inflammatory status, resulting in improved graft survival. Although the majority of clinical studies confirmed these results, reporting about improved recovery and superior organ function, others failed to do so. Yet, only a limited number of micronutrients and natural compounds have been investigated in a (large) clinical trial. Despite some ambiguous clinical results and modest clinical data availability, the vast majority of convincing animal and in vitro data, along with low cost and easy availability, encourage the conductance of future clinical trials. These should implement insights gained from animal data.

Effect of resveratrol treatment on apoptosis and apoptotic pathways during boar semen freezing

Resveratrol (3,5,4'-trihydroxystilbene, RSV) has been widely used in mammalian cells, but whether it can be used during freezing boar semen is still unknown. The effects of RSV treatment during boar semen freezing on its anti-freezing ability, apoptosis, and possible apoptotic pathways were observed in this study. Sperm motility, mitochondrial membrane potential (ΔΨ_m), adenosine triphosphate (ATP) content, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL)-positive apoptotic state, and messenger RNA (mRNA) expression levels of apoptotic genes involved in different apoptotic pathways after freezing with or without RSV treatment were tested. The results showed that: (1) Compared with fresh sperm, the motility, normal acrosome rate, and plasma membrane integrity rate of frozen boar sperm decreased significantly (P<0.05), and RSV did not significantly increase the sperm motility (0.44 vs. 0.40, P>0.05), but it did significantly improve the normal acrosome rate (57.65% vs. 47.00%, P<0.05) and plasma membrane integrity rate (46.67% vs. 38.85%, P<0.05). (2) After freezing, most boar sperm showed low mitochondrial ΔΨ_m. RSV treatment could increase the rate of high mitochondrial ΔΨ_m of boar sperm. (3) RSV treatment significantly decreased reactive oxygen species (ROS) levels (58.65% vs. 88.41%, P<0.05) and increased the ATP content (0.49 μmol/L vs. 0.25 μmol/L, P<0.05) of boar sperm during freezing. (4) The apoptotic rate of the freezing group (80.41%) with TUNEL detection increased significantly compared to the fresh group (9.70%, P<0.05), and RSV treatment greatly decreased the apoptotic rate (68.32%, P<0.05). (5) Real-time polymerase chain reaction (RT-PCR) showed that not only the genes from the death receptor-mediated apoptotic pathway (tumor necrosis factor-α (TNF-α), Fas ligand (FasL), and Caspase-8), but also the genes from the mitochondria-mediated apoptotic pathway (manganese superoxide dismutase (MnSOD), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and Caspase-9) were both significantly changed after freezing. RSV treatment during freezing greatly changed their expression levels. Although RSV treatment during boar semen freezing did not significantly increase motility after thawing, it still played an efficient antioxidant role, which could enhance the mitochondrial function and decrease the apoptotic level induced by both the death receptor- and mitochondria-mediated apoptotic pathways.

Cytoprotective Effects of Mesenchymal Stem Cells During Liver Transplantation From Donors After Cardiac Death in Swine

BACKGROUND

Liver transplantation from donors after cardiac death (DCDs) can increase the pool of available organs. Recently, mesenchymal stem cells (MSCs) have been used to treat various diseases. Some studies have reported that MSCs improve the outcome of liver transplantation from DCDs in mice. The aim of this study was to evaluate the cytoprotective effects and safety of MSC transplantation on liver grafts from DCDs in swine.

METHODS

For the MSCs, we used swine adipose-derived stem cells (ADSCs). Landrace swine were divided into 3 groups (n = 5) as follows: 1. the heart-beating (HB) group, from which liver grafts were retrieved and transplanted; 2. the DCD group, from which liver grafts were retrieved 10 minutes after apnea-induced cardiac arrest and transplanted; and 3. the ADSC group, from which liver grafts were retrieved as with the DCD group, transplanted, and then infused with 1.0 × 10⁷ ADSCs 2 hours after reperfusion.

RESULTS

In the HB group, all 5 recipients survived for >7 days, whereas all 5 recipients in the DCD group died within 24 hours after transplantation. In the ADSC group, 3 recipients survived for >7 days, whereas 2 recipients died within 4 days after transplantation. The survival rate was significantly higher in the ADSC group than in the DCD group.

CONCLUSIONS

MSCs could protect the function of liver grafts from warm ischemia-reperfusion injury and improve the viability of DCD liver grafts.

Histomorphometric evaluation of the rat kidney submitted to warm ischemia and the protective effect of resveratrol

BACKGROUND

The objective of this study is to quantitatively evaluate the protective effects of resveratrol for using during renal warm ischemia.

METHODS

Rats were allocated into 4 groups: Sham, Sham Resveratrol, Ischemia, Ischemia Resveratrol. Sham Resveratrol and Ischemia Resveratrol received resveratrol before surgery. Ischemia and Ischemia Resveratrol had renal vessels clamped. Animals were euthanized four weeks after. Serum urea and creatinine were measured. Renal weight and volume, cortex-non-cortex areas ratio, cortical volume, glomerular volumetric density, volume-weighted mean glomerular volume and number of glomeruli per kidney were evaluated.

RESULTS

Serum urea in Ischemia increased by 10.4% compared to Sham and no differences were observed among Ischemia Resveratrol and sham groups. The glomerular volumetric density and number of glomeruli of Ischemia were lower than Sham but Ischemia Resveratrol had no difference compared to sham groups.

CONCLUSIONS

Preoperative administration of resveratrol has renoprotective effects, preventing the glomerular number reduction observed in warm ischemia.

Cytoprotective Effects of Mesenchymal Stem Cells During Liver Transplantation from Donors After Cardiac Death in Rats

BACKGROUND

Liver transplantation from donors after cardiac death (DCD) might increase the pool of available organs. Recently, some investigators reported the potential use of mesenchymal stem cells (MSCs) to improve the outcome of liver transplantation from DCD. The aim of this study was to evaluate the cytoprotective effects and safety of MSC transplantation on liver grafts from DCD.

METHODS

Rats were divided into 4 groups (n = 5) as follows: 1. the heart-beating group, in which liver grafts were retrieved from heart-beating donors; 2. the DCD group, in which liver grafts were retrieved from DCD that had experienced apnea-induced agonal conditions; 3. the MSC-1 group, and 4. the MSC-2 group, in which liver grafts were retrieved as with the DCD group, but were infused MSCs (2.0 × 10⁵ or 1.0 × 10⁶, respectively). The retrieved livers were perfused with oxygenated Krebs-Henseleit bicarbonate buffer (37°C) through the portal vein for 2 hours after 6 hours of cold preservation. Perfusate, bile, and liver tissues were then investigated.

RESULTS

Bile production in the MSC-2 group was significantly improved compared with that in the DCD group. Based on histologic findings, narrowing of the sinusoidal space in the both MSC groups was improved compared with that in the DCD group.

CONCLUSIONS

MSCs could protect the function of liver grafts from warm ischemia-reperfusion injury and improve the viability of DCD liver grafts. In addition, we found that the infusion of 1.0 × 10⁶ MSCs does not obstruct the hepatic sinusoids of grafts from DCD.