Cell-derived microparticles and von Willebrand factor in Brazilian renal transplant recipients.

AIM: This study was aimed at investigating platelet-derived microparticles (PMP), endothelium cell-derived microparticles (EMP) and von Willebrand factor (VWF) according to renal function and time post-transplant. We found this study relevant because unusual biomarkers seem to be a promising tool to evaluate chronic renal disease and post-transplant monitoring. METHODS: Ninety-one renal transplant recipients (RTx) were allocated into groups according to creatinine plasma levels (C1 < 1.4 and C2 ≥ 1.4 mg/dL), estimated glomerular filtration rates (R1 < 60 and R2 ≥ 60 mL/min per 1.73 m2 ) and time post-transplant (T1: 3-24; T2: 25-60; T3: 61-120; and T4 > 120 months). EMP and PMP levels were assessed by flow cytometry and VWF levels were evaluated by enzyme-linked immunosorbent assay. RESULTS: Platelet-derived microparticle levels were higher in C1 group compared with C2 (P = 0.00). According to diameter, small PMP and EMP (≤0.7 µm) were also higher in C1 group, all values of P less than 0.05. T1 and T2 groups have shown high EMP levels and a predominance of big microparticle (>0.7 µm) compared with T4 group, all values of P less than 0.05. Higher VWF levels were observed among RTx with creatinine ≥1.4 mg/dL compared with other RTx, P = 0.01. CONCLUSION: The results showed that PMP, EMP and VWF are promising markers to evaluate endothelial function in RTx. These biomarkers could play a major role in monitoring patients after renal transplant.

Regulatory and pro-inflammatory cytokines in Brazilian living-related renal transplant recipients according to creatinine plasma levels.

AIM: The maintenance of stable graft function in renal transplanted recipients (RTR) is a challenge for healthcare staff. The ideal biomarkers must have significant predictive values to monitor the intricate renal function response triggered after renal transplantation. The main purpose in this study was to evaluate the regulatory and pro-inflammatory cytokines as biomarkers of allograft function in living-related renal transplant patients. METHODS: Regulatory and pro-inflammatory cytokine plasma levels were measured by flow cytometry in 120 living-related renal transplanted patients categorized into three groups according to creatinine plasma levels: creatinine less than 1.4 mg/dL (C1), creatinine within 1.4-2.0 mg/dL (C2) and more than 2.0 mg/dL (C3). Patients were also classified as 'low' or 'high' cytokine producers. Clinical data were obtained from patients' medical record. RESULTS: We have found a peak of regulatory cytokines in RTR with low creatinine levels as well as a peak of IL-6 pro-inflammatory cytokine in patients with high creatinine levels. C1 and C3 groups showed a mixed pro-inflammatory (IL-8, IL-6, IL-1ß, TNF-α, IL-12 and IFN-γ) and regulatory (IL-4, IL-5 and IL-10) cytokine pattern and C2 had a predominant pro-inflammatory profile. C3 group showed a higher frequency of high pro-inflammatory cytokine producers compared to C1. CONCLUSION: Our data suggest that regulatory cytokines IL-4, IL-5 and IL-10 could be good biomarkers associated with stable renal function, while pro-inflammatory cytokines seems to be potential markers in RTR related to high creatinine plasma levels, specially IL-6 despite of its borderline values.

Thrombomodulin and interleukin 6 as potential biomarkers of endothelial dysfunction and inflammation after renal transplant / Trombomodulina e interleucina 6 como potenciais biomarcadores da disfunção endotelial e da inflamação pós-transplante renal

ABSTRACT Introduction: Endothelial dysfunction may contribute to hypercoagulable and inflammation states presents in renal transplant, chronic kidney disease (CKD) and its causes. These disorders can be evaluated by markers, such as thrombomodulin (TM), von Willebrand factor (vWF) and interleukin 6 (IL-6). Objectives: The aim of this study was to assess TM, vWF and IL-6 in renal transplant recipients (RTR) and associate their plasma levels with primary cause of end-stage renal disease (ESRD) and allograft function. Methods: 160 RTR were grouped according to the primary cause of CKD (G1: glomerulopathy; G2: hypertensive nephrosclerosis; G3: diabetic nephropathy; and G4: other causes/unknown etiology); creatinine plasma levels (C1 < 1.4 and C2 ≥ 1.4 mg/dl); and the estimated glomerular filtration rate (eGFR) (R1< 60 and R2 ≥ 60 ml/min/1.73 m2). TM and vWF were determined by the enzyme-linked immunosorbent assay (ELISA) and IL-6 by flow cytometry. The results were presented as median, minimum and maximum; p-value < 0.05 was considered statistically significant. Results: TM levels were significantly higher in the G1 group compared to the others (G1: 8.38; G2: 5.51; G3: 5.88; G4: 6.33 ng/ml, p < 0.0001), and in the R1 group compared to R2 (R1: 6.65; R2: 6.19 ng/ml, p = 0.02). The concentration of IL-6, measured by the mean fluorescence intensity, was higher in C2 group when compared to C1 (C1: 7.9; C2: 13.35, p = 0.03). There was no difference in vWF levels among groups. TM correlated positively with IL-6 and creatinine, and negatively with eGFR. IL-6 also correlated positively with vWF. Conclusion: TM and IL-6 can be identified as potential markers for evaluating renal graft function. TM was more related to the primary cause of CKD compared to vWF and IL-6.

RESUMO Introdução: A disfunção endotelial pode contribuir para estados de hipercoagulabilidade e inflamação presentes no transplante renal e na doença renal crônica (DRC) e suas causas, podendo ser avaliada por marcadores como trombomodulina (TM), fator de von Willebrand (FvW) e interleucina 6 (IL-6). Objetivos: Avaliar TM, FvW e IL-6 em receptores do transplante renal (RTR) e associar seus níveis com a causa primária de DRC pré-transplante e função do enxerto. Métodos: Foram alocados 160 RTR em grupos de acordo com a causa primária da DRC (G1: glomerulopatias; G2: nefroesclerose hipertensiva; G3: nefropatia diabética; e G4: outras causas/etiologia desconhecida), os níveis plasmáticos de creatinina (C1 < 1.4 e C2 ≥ 1.4 mg/dl) e o ritmo de filtração glomerular estimado (eRFG) (R1< 60 e R2 ≥ 60 ml/min/1.73 m2). A TM e o FvW foram determinados pelo ensaio de imunoabsorção enzimática (ELISA) e a IL-6, por citometria de fluxo. Os resultados foram apresentados como mediana, mínimo e máximo; p < 0,05 foi considerado significativo. Resultados: Níveis de TM foram significativamente maiores no grupo G1 em comparação com os demais (G1: 8,38; G2: 5,51; G3: 5,88; G4: 6,33 ng/ml, p < 0,0001), e no grupo R1 comparado com o R2 (R1: 6,65; R2: 6,19 ng/ml, p = 0,02). A concentração de IL-6, avaliada pela intensidade média de fluorescência, foi maior no grupo C2 quando comparada com o C1 (C1: 7,9; C2: 13,35, p = 0,03). Não houve diferença entre os grupos para o FvW. TM correlacionou-se positivamente com IL-6 e creatinina e negativamente com eRFG. A IL-6 foi positivamente correlacionada com o FvW. Conclusão: TM e IL-6 podem ser apontadas como potenciais marcadores para avaliar a função do enxerto renal. A TM relacionou-se mais com a causa primária da DRC, se comparada com FvW e IL-6.