Acute Kidney Injury After Neonatal Aortic Arch Surgery: Deep Hypothermic Circulatory Arrest Versus Moderate Hypothermia With Distal Aortic Perfusion

Internal translation of Gja1 (Connexin43) to produce GJA1-20k: Implications for arrhythmia and ischemic-preconditioning

Internal translation is a form of post-translation modification as it produces different proteins from one mRNA molecule by beginning translation at a methionine coding triplet downstream of the first methionine. Internal translation can eliminate domains of proteins that otherwise restrict movement or activity, thereby creating profound functional diversity. Connexin43 (Cx43), encoded by the gene Gja1, is the main gap junction protein necessary for propagating action potentials between adjacent cardiomyocytes. Gja1 can be internally translated to produce a peptide 20 kD in length named GJA1-20k. This review focuses on the role of GJA1-20k in maintaining cardiac electrical rhythm as well as in ischemic preconditioning (IPC). Connexin43 is the only ion channel we are aware that has been reported to be subject to internal translation. We expect many other ion channels also undergo internal translation. The exploration of post-translational modification of ion channels, and in particular of internal translation, has the potential to greatly increase our understanding of both canonical and non-canonical ion channel biology.

Comparison of cases with and without additional lower body perfusion in newborns undergoing aortic arch reconstruction with antegrade selective cerebral perfusion method

Background

The aim of this study was to analyze the effect of additional lower body perfusion, compared to antegrade selective cerebral perfusion, on early postoperative outcomes after aortic arch repair in neonates with biventricular morphology.

Methods

Between January 2017 and April 2020, a total of 46 neonates (34 males, 12 females; median age: 10 days; range, 7 to 14 days) with biventricular morphology underwent an aortic arch reconstruction were retrospectively analyzed. The effects of antegrade selective cerebral perfusion and additional lower body perfusion techniques on vital organ preservation and mortality were evaluated in these patients who underwent arch reconstruction.

Results

In the univariate analysis of the whole cohort, postoperative creatinine level was lower in the additional lower body perfusion group, while there was no significant difference between the other parameters. In the multivariate analysis, intraoperative highest lactate level (odds ratio: 1.7; 95% confidence interval: 1.07-2.68; p=0.02) and postoperative 4th t o 6 th h lactate levels (odds ratio: 2.34; 95% confidence interval: 1.08-5.09; p=0.03) were independent predictors of early mortality. Mortality rate was higher in the antegrade selective cerebral perfusion group (22% vs. 7%), although it did not reach statistical significance. In the receiver operating characteristic curve analysis, the cut-off value for intraoperative lactate was 6.2 mmol/L (sensitivity: 85.7%, specificity: 71.1%) and the cut-off value for the lactate level at the postoperative 4th to 6th h was 4.9 mmol/L (sensitivity: 85.7%, specificity: 73.7%). Above these lactate levels were found to be associated with mortality.

Conclusion

Additional lower body perfusion may have a role in vital organ protection in aortic arch repair of neonates, compared to antegrade selective cerebral perfusion.