The Predictive Value of Graft Viability and Bioenergetics Testing Towards the Outcome in Liver Transplantation

Donor organ biomarkers with sufficient predictive value in liver transplantation (LT) are lacking. We herein evaluate liver viability and mitochondrial bioenergetics for their predictive capacity towards the outcome in LT. We enrolled 43 consecutive patients undergoing LT. Liver biopsy samples taken upon arrival after static cold storage were assessed by histology, real-time confocal imaging analysis (RTCA), and high-resolution respirometry (HRR) for mitochondrial respiration of tissue homogenates. Early allograft dysfunction (EAD) served as primary endpoint. HRR data were analysed with a focus on the efficacy of ATP production or P-L control efficiency, calculated as 1-L/P from the capacity of oxidative phosphorylation P and non-phosphorylating respiration L. Twenty-two recipients experienced EAD. Pre-transplant histology was not predictive of EAD. The mean RTCA score was significantly lower in the EAD cohort (-0.75 ± 2.27) compared to the IF cohort (0.70 ± 2.08; p = 0.01), indicating decreased cell viability. P-L control efficiency was predictive of EAD (0.76 ± 0.06 in IF vs. 0.70 ± 0.08 in EAD-livers; p = 0.02) and correlated with the RTCA score. Both RTCA and P-L control efficiency in biopsy samples taken during cold storage have predictive capacity towards the outcome in LT. Therefore, RTCA and HRR should be considered for risk stratification, viability assessment, and bioenergetic testing in liver transplantation.

Live Confocal Imaging as a Novel Tool to Assess Liver Quality: Insights From a Murine Model

BACKGROUND

In an experimental murine liver clamping model, we aimed to investigate the efficacy of real-time confocal microscopy (RCM) in assessing viability of steatotic livers in comparison to standard assessment tools, including histopathological evaluation.

METHODS

C57Bl/6 mice were subjected to a methionine-choline-deficient diet causing nonalcoholic fatty liver disease or to Lieber DeCarli diet causing ethanol-induced liver injury. Untreated animals served as controls. Liver biopsies were analyzed following challenge with 45 min of warm ischemia time and either 4 h of reperfusion or 24 h of cold storage. Organ quality assessment was performed at defined time points by RCM, histological staining, measurement of serum alanine aminotransferase activity, and expression analyses of proinflammatory cytokines. Additionally, survival analysis was performed.

RESULTS

Cold as well as warm ischemia time resulted in a significant decrease in cell viability when compared with naive livers as well as nonischemic-challenged steatotic livers (P < 0.05) as assessed by RCM. Furthermore, RCM revealed the actual cellular damage at early time points, while established methods including H&E-staining and serum transaminase profile failed.

CONCLUSIONS

In a translational attempt, we demonstrate that RCM is a suitable diagnostic tool to obtain information about functional damage of the liver apart from standard approaches.

Cell-penetrating self-nanoemulsifying drug delivery systems (SNEDDS) for oral gene delivery

OBJECTIVE

The aim of study was to investigate whether cell-penetrating peptides could amplify cellular uptake of plasmid DNA (pDNA) loaded self-nanoemulsifying drug delivery systems (SNEDDS) by mucosal epithelial cells, thereby enhancing transfection efficiency.

METHODS

HIV-1 Tat peptide-oleoyl conjugate (TAT-OL) was synthesized through amide bond formation between HIV-1 Tat-protein 49-57 (TAT) and oleoyl-chloride (OL). SNEDDS formulation contained 29.7% each of Cremophor EL, Capmul MCM and Crodamol, 9.9% propylene glycol and 1% TAT-OL. SNEDDS with OL instead of TAT-OL served as control.

RESULTS

Fluorescent-microscopy demonstrated 0.5% (m/v) nanoemulsions were suitable for subsequent studies. Mucus diffusion of nanoemulsion loaded with fluorescein diacetate (FDA) was 1.5-fold increased by incorporation of TAT-OL. Confocal microscopy confirmed that droplets of nanoemulsions were successfully internalized. Furthermore, quantitative analysis showed that addition of TAT-OL increases uptake of nanoemulsions by 2.3- and 2.6-folds after 2 and 4 hours of incubation, respectively. Cellular internalization pathways were found with substantial decrease in uptake in presence of indomethacin and chlorpromazine. Transfection efficiency investigated on HEK-293-cells was found to be 1.7- and 1.8-fold higher for SNEDDS loaded with TAT-OL compared to Lipofectin and control, respectively.

CONCLUSION

In comparison to prevailing lipid and polymer-based delivery systems, these novel cell-penetrating SNEDDS likely represent most effective, simplistic and expedite dosage form for mucosal gene delivery.