Título

EVALUATION OF GLOBAL DNA METHYLATION PROFILE IN NON-IDEAL KIDNEY DONORS

Resumo

Background: Non-ideal deceased donor kidneys classified as extended criteria (ECD) or with high kidney donor profile index (KDPI > 85%) when not discarded could significantly reduce the waiting list for kidney transplantation. The epigenome of non-ideal kidneys may be affected by modifiers such as brain death and cold ischemia driving the onset and progression of chronic allograft injury. Studies evaluated on methylation and kidney transplantation are scarce in the literature, making this study unprecedented and can be used as biomarkers to offer therapeutic strategies to reduce the inflammatory activity of these organs. Objectives: To identify DNA methylation, expression of DNA methyltransferases (DNMTs) responsible for methylation and ten eleven translocases (TET) responsible for the inverse process of methylation profiles in preimplantation kidney biopsies (PIBx) in non-ideal kidneys. Methods: Global DNA methylation in pre-implantation kidney biopsies from ECD and KDPI > 85% kidneys was estimated by analyzing LINE-1 repeats and Alu repeated elements using bisulfite pyrosequencing. DNMTs and TET genes expression were assessed by a real-time quantitative polymerase chain reaction. Results: ECD donors were older had more cerebrovascular accident and arterial hypertension (p < 0.01) and recipients of ECD kidneys had renal function worst 1 year after transplantation (p= 0.008). ECD biopsies showed significantly increase hypermethylation for the Alu (p= 0.03) and LINE-1 (p= 0.03) repetitive sequence. DNMT1 and DNMT3B showed high expression in ECD than in SCD (p= 0.04; p= 0.03, respectively). Compared with kidneys with KDPIs ≤ 85%, kidneys with KDPIs > 85% showed LINE-1 significantly hypermethylated (p= 0.04) and upregulation of DNMT1 (p=0.04). The expression of TET (KDPI > 85%= 0.84 ± 0.81 vs. KDPI> 85%= 1.78 ± 2.39 P=0.08) were numerically smaller in the KDPI > 85% group, but the difference did not reach statistical significance. The logistic regression analysis showed that cold ischemia time (CIT) > 21h was associated with hypermethylation for sites 1 of the Alu (OR=7.7) and sites 1 sitio 3 of the LINE-1 (OR= 5.0 and OR= 6.25, respectively). Conclusion: Our results provide evidence that DNA methylation changes in low-quality kidneys can be linked to the inflammatory activity of these organs and epigenetic changes analysis may be a viable tool for evaluation of non-ideal kidneys.

Área

Transplante

Autores

HELOISA C CALDAS, Naiane do Nascimento Gonçalves, Giovana Mattiello Sormani, Ida Maria Maximina Fernandes-Charpiot, Maria Alice Sperto Ferreira Baptista, Rogério Moraes Castilho, Lídia Maria Rebolho Batista Arantes, Heloisa Cristina Caldas, Mario Abbud-Filho