Understanding endothelial dysfunction in kidney transplantation: assessment techniques, existing evidence, and research needs

INTRODUCTION: Kidney transplant recipients (KTRs) have substantially lower risk for cardiovascular events compared to dialysis, but it remains significantly higher than in the general population due to the synergistic action of traditional and nontraditional factors. Among them, endothelial dysfunction is suggested to be involved pathogenetically in cardiovascular and renal disease progression, with its improvement being another potential benefit of transplantation. AREAS COVERED: VOP was the first technique to be used, followed by several functional methods, most commonly FMD. Over the years, several biomarkers of endothelial dysfunction have been used to assess microvascular function. The totality of evidence in KTRs suggests the improvement of endothelial dysfunction after transplantation, but with several gaps in knowledge, including rarity of studies using novel, more accurate techniques. This review presents the current functional methods and biomarkers used to evaluate microvascular and endothelial function in KTRs, discussing the existing evidence on their changes after transplantation and their associations with comorbidities and outcomes in this population. A comprehensive literature search was conducted in PubMed and Scopus for articles published until December 2024. EXPERT OPINION: Novel methods assessing endothelial function offer a comprehensive, real-time evaluation of microvascular function and should be more widely used to enhance our understanding in this area.