Necroptosis-related genes allow novel insights into predicting graft loss and diagnosing delayed graft function in renal transplantation.

Ischemia-reperfusion injury (IRI) is an inevitable pathophysiological phenomenon in kidney transplantation. Necroptosis is an undoubtedly important contributing mechanism in renal IRI. We first screened differentially expressed necroptosis-related genes (DENRGs) from public databases. Eight DENRGs were validated by independent datasets and verified by qRT-PCR in a rat IRI model. We used univariate and multivariate Cox regression analyses to establish a prognostic signature, and graft survival analysis was performed. Immune infiltrating landscape analysis and gene set enrichment analysis (GSEA) were performed to understand the underlying mechanisms of graft loss, which suggested that necroptosis may aggravate the immune response, resulting in graft loss. Subsequently, a delayed graft function (DGF) diagnostic signature was constructed using the Least Absolute Shrinkage and Selection Operator (LASSO) and exhibited robust efficacy in validation datasets. After comprehensively analyzing DENRGs during IRI, we successfully constructed a prognostic signature and DGF predictive signature, which may provide clinical insights for kidney transplant.

Micro RNA 146a-5p expression in Kidney transplant recipients with delayed graft function / Expressão do Micro RNA 146a-5p em pacientes transplantados renais com disfunção inicial do enxerto

ABSTRACT Introduction: The development of novel non-invasive biomarkers of kidney graft dysfunction, especially in the course of the delayed graft function period would be an important step forward in the clinical practice of kidney transplantation. Methods: We evaluated by RT-PCR the expression of miRNA-146 to -5p ribonucleic micro-acids (miRNAs) in the peripheral blood and renal tissue obtained from kidney transplant recipients who underwent a surveillance graft biopsy during the period of delayed graft function. Results: In biopsy samples, the expression of miR-146a-5p was significantly increased in the group of patients with delayed graft function (DGF) (n = 33) versus stables patients (STA) (n = 13) and patients with acute rejection (AR) (n = 9) (p = 0.008). In peripheral blood samples, a non-significant increase of miR-146a-5p expression was found in the DGF group versus STA and AR groups (p = 0.083). No significant correlation was found between levels of expression in biopsy and plasma. ROC curve analysis revealed an AUC of 0.75 (95% CI: 0.62-0.88) for the renal tissue expression and 0.67 (95% CI 0.52-0.81) for the peripheral blood expression. Conclusion: We conclude that miR-146a-5p expression has a distinct pattern in the renal tissue and perhaps in the peripheral blood in the setting of DGF. Further refinements and strategies for studies should be developed in the field of non-invasive molecular diagnosis of kidney graft dysfunction.

RESUMO Introdução: O desenvolvimento de novos biomarcadores não invasivos para disfunção do enxerto renal, especialmente no decurso da disfunção inicial do enxerto, seria de enorme valia para a prática clínica do transplante renal. Métodos: A técnica de RT-PCR foi utilizada para avaliar a expressão de microRNA 146a-5p no sangue periférico e no tecido renal de receptores de transplante submetidos a biópsia renal de controle no decurso de disfunção inicial do enxerto. Resultados: A expressão de miR-146a-5p estava significativamente aumentada nas amostras de biópsia do grupo de pacientes com disfunção inicial do enxerto (DIE) (n = 33) em relação aos pacientes estáveis (n = 13) e aos com rejeição aguda (RA) (n = 9) (p = 0,008). Foi detectado aumento não significativo da expressão de miR-146a-5p nas amostras de sangue periférico do grupo com DIE em comparação aos pacientes estáveis e com RA (p = 0,083). Não foi identificada correlação significativa entre os níveis de expressão no plasma e na biópsia. A análise da curva COR revelou uma ASC de 0,75 (IC 95%: 0,62-0,88) para a expressão no tecido renal e de 0,67 (IC 95% 0,52-0,81) no sangue periférico. Conclusão: A expressão de miR-146a-5p tem um padrão distinto no tecido renal e talvez no sangue periférico em cenários de DIE. Maiores refinamentos e estratégias adicionais de estudo devem ser desenvolvidos na área do diagnóstico molecular não invasivo da disfunção do enxerto renal.