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Background and objective: Renal artery aneurysm (RAA) is a rare condition. Our study investigates the effectiveness and outcomes of surgical treatments for complex RAA, comparing the in situ (IS) and ex vivo autotransplantation (AT) methods. Methods: We conducted a retrospective study from June 2015 to March 2023, including all consecutive patients treated surgically for complex RAA in our center. We focused on patients with complex RAA locations requiring open surgical multidisciplinary treatment, excluding those with simple aneurysms or who were treated endovascularly. Preoperative data including demographics, comorbidities, and cardiovascular risk factors were collected. The measured primary outcome was the absence of residual aneurysm and main renal arterial thrombosis after surgery. The secondary outcomes included pre- and postoperative kidney perfusion analyses and surgical complications as per Clavien-Dindo classification. Differences between AT and IS were assessed by Wilcoxon, chi-square, or Fischer’s exact test. Key findings and limitations: Twenty-seven aneurysms were treated in 25 patients. No residual aneurysm or main artery thrombosis was found after surgery. Ten (40%) patients underwent AT surgery. The median kidney perfusion differences were 2 cc (-12; 13), 0 cc (-13; 10), and 2 cc (-10; 13; p = 0.41) in the whole, AT, and IS cohorts, respectively. Clavien-Dindo grade 1 and 2 complications occurred in 11% and 30% of patients, respectively, with no grade 3 or 4 complications observed. Conclusions and clinical implications: Complex RAA can be managed effectively through open surgery, ensuring good ipsilateral renal preservation and tolerable toxicity. Both AT and IS surgeries yielded similar outcomes. Further multicenter studies are warranted to confirm our findings. Patient summary: This study explored the treatment of a rare kidney blood vessel condition called renal artery aneurysm using two surgical approaches. Our findings suggest that both surgical techniques are effective in treating this condition without major complications, ensuring good kidney preservation. These promising results need further confirmation through larger studies across different medical centers.

Abstract As the use of elderly kidney donors for transplantation is increasing with time, there is a need to understand which factors impact on their prognosis. No data exist on the impact of an impaired renal function (IRF) in such population. 116 kidney recipients from deceased kidney donors over 70 years were included from 2005 to 2015 in a single-center retrospective study. IRF before organ procurement was defined as a serum creatinine above 1.0 mg/dl or a transient episode of oligo-anuria. Mean ages for donors and recipients were respectively 74.8 ± 3.5 and 66.7 ± 8.0. Graft survival censored for death at 5 years was of 77%. Using a multivariate analysis by Cox model, the only predictor of graft loss present in the donor was IRF before organ procurement (HR 4.2 CI95[1.8–9.7]). IRF was also associated with significant lower estimated glomerular filtration rates up to 1 year post-transplantation. By contrast, KDPI score (median of 98 [96–100]), was not associated with the risk of graft failure. Then, IRF before kidney procurement may define a risk subgroup among very-old deceased kidney donors, in whom pre-implantatory biopsies, dual kidney transplantation or calcineurin inhibitor-free immunosuppressive regimen could help to improve outcomes.

MicroRNAs (miRNAs) are a class of noncoding RNA acting at a post-transcriptional level to control the expression of large sets of target mRNAs. While there is evidence that miRNAs deregulation plays a causative role in various complex disorders, their role in fibrotic kidney diseases is largely unexplored. Here, we found a strong up-regulation of miR-21 in the kidneys of mice with unilateral ureteral obstruction and also in the kidneys of patients with severe kidney fibrosis. In addition, mouse primary fibroblasts derived from fibrotic kidneys exhibited higher miR-21 expression level compared to those derived from normal kidneys. Expression of miR-21 in normal primary kidney fibroblasts was induced upon TGFβ exposure, a key growth factor involved in fibrogenesis. Finally, ectopic expression of miR-21 in primary kidney fibroblasts was sufficient to promote myofibroblast differentiation. As circulating miRNAs have been suggested as promising non-invasive biomarkers, we further assess whether circulating miR-21 levels are associated with renal fibrosis using sera from 42 renal transplant recipients, categorized according to their renal fibrosis severity, evaluated on allograft biopsies (Interstitial Fibrosis/Tubular Atrophy (IF/TA). Circulating miR-21 levels are significantly increased in patients with severe IF/TA grade (IF/TA grade 3: 3.0±1.0 vs lower grade of fibrosis: 1.5±1.2; p = 0.001). By contrast, circulating miR-21 levels were not correlated with other renal histological lesions. In a multivariate linear regression model including IF/TA grade and estimated GFR, independent associations were found between circulating miR-21 levels and IF/TA score (ß = 0.307, p = 0.03), and between miR-21 levels and aMDRD (ß = -0.398, p = 0.006). Altogether, these data suggest miR-21 has a key pathogenic role in kidney fibrosis and may represent a novel, predictive and reliable blood marker of kidney fibrosis.