ABSTRACT
PURPOSE: The clinical outcomes of kidney transplantation from deceased donors have seen significant improvements with the use of machine perfusion (MP), now a standard practice in transplant centers. However, the use of perfusate biomarkers for assessing organ quality remains a subject of debate. Despite this, some centers incorporate them into their decision-making process for donor kidney acceptance. Recent studies have indicated that lactate dehydrogenase (LDH), glutathione S-transferase, interleukin-18, and neutrophil gelatinase-associated lipocalin (NGAL) could predict post-transplant outcomes. MATERIALS AND METHODS: Between August 2016 and June 2017, 31 deceased-donor after brain death were included and stroke was the main cause of death. Pediatric patients, hypersensitized recipients were excluded. 43 kidneys were subjected to machine perfusion. Perfusate samples were collected just before the transplantation and stored at -80ºC. Kidney transplant recipients have an average age of 52 years, 34,9% female, with a BMI 24,6±3,7. We employed receiver operating characteristic analysis to investigate associations between these perfusate biomarkers and two key clinical outcomes: delayed graft function and primary non-function. RESULTS: The incidence of delayed graft function was 23.3% and primary non-function was 14%. A strong association was found between NGAL concentration and DGF (AUC=0.766, 95% CI, P=0.012), and between LDH concentration and PNF (AUC=0.84, 95% CI, P=0.027). Other perfusate biomarkers did not show significant correlations with these clinical outcomes. CONCLUSION: The concentrations of NGAL and LDH during machine perfusion could assist transplant physicians in improving the allocation of donated organs and making challenging decisions regarding organ discarding. Further, larger-scale studies are required.
Subject(s)
Biomarkers , Delayed Graft Function , Kidney Transplantation , Lipocalin-2 , Organ Preservation , Perfusion , Humans , Female , Biomarkers/analysis , Male , Middle Aged , Perfusion/methods , Adult , Lipocalin-2/analysis , Organ Preservation/methods , Tissue Donors , ROC Curve , Treatment Outcome , Time Factors , L-Lactate Dehydrogenase/analysis , Reference Values , Predictive Value of TestsABSTRACT
BACKGROUND: The effect of mercury (Hg(2+)) on the activity of choline acetyltransferase (ChAT) from electrocytes of Electrophorus electricus (L.) was studied due to the importance of this enzyme and acetylcholine in many neurochemical functions such as arousal, learning, and memory. MATERIAL/METHODS: Mercury, which has affinity to thiol groups, acted as a potent inhibitor of ChAT, which was obtained by differential centrifugation and ammonium sulfate precipitation, at 80%, from the main electric organ homogenate. RESULTS: Mercury inhibition presents different kinetic behaviors for both enzyme substrates: noncompetitive to choline and of mixed type to AcCoA, with inhibition constants on the order of 0.5 to 1.0 microM. The enzyme activity was recovered using 2,3 dimercapto-propanol (BAL), a well-known chelate for sulphydryl groups and metals, which acted as a protecting agent and was able to revert the Hg(2+) inhibition at a concentration of 10 (-6) M. After treatment with this metal and in the presence of 2,3 dimercapto-propanol, 70% of the enzyme activity was recovered for AcCoA and 80% for choline. CONCLUSIONS: The observed inhibition is likely due to direct protein interaction, because the addition of BAL reversed the effects of HgCl(2) on ChAT activity. The results cast new light on the mechanisms of mercurial neurotoxicity.
