Project description:The fate of transplanted kidneys is substantially influenced by the graft quality as transplantation of kidneys from elderly and expanded criteria deceased donors (ECD) is associated with higher occurrence of delayed graft function, rejection and inferior long term outcome. Little is known about early molecular fingerprints of these events in different donor categories. Borderline changes represent the most frequent histological finding early after kidney transplantation. Therefore, transcriptomic profiles of early case biopsies diagnosed as borderline changes were studied in ECD, standard criteria deceased donors (SCD) and living donor (LD) kidney transplantation using RNA microarray (Agilent SurePrintG3). The increased transcripts typical for ECD as compared to LD (n=437) showed enrichment of extracellular matrix (ECM) -receptor interaction (p=0.004) and complement and coagulation pathways (p=0.004) and GO terms related to platelet activation, blood coagulation, regulation of cell cycle, acute inflammatory response, wound healing or defense response (p<0.001). Gene annotation analysis of transcripts with increased expression in ECD grafts compared to SCD (n=244) showed the highest enrichment of inflammatory response (p=0.013), response to wounding (p=0.001) and defense response (p=0.005) and ECM-receptor interaction pathway (p=0.043). Comparative gene expression overlaps of ECD, SCD and LD using Venn’s diagrams found 62 up- and 16 down-regulated genes in ECD compared to both LD and SCD. Shared increased transcripts in ECD vs. both SCD and LD included, thrombospondin 2 (THBS2), angiopoietin-like 4 (ANGPTL4), collagens (COL6A3, COL1A1), chemokines CCL13 or interleukin IL11 and most significant down-regulated transcripts included proline rich 35 (PRR35) and fibroblast growth factor 9 (FGF9). Transcriptomic profile of higher inflammation and extracellular matrix remodeling in early borderline changes in the ECD kidney allografts suggest mechanisms how ischemia/reperfusion injury aggravates alloimmune response in the presence of chronic vascular changes.

Project description:The fate of transplanted kidneys is substantially influenced by graft quality, with transplantation of kidneys from elderly and expanded criteria donors (ECDs) associated with higher occurrence of delayed graft function, rejection, and inferior long-term outcomes. However, little is known about early molecular fingerprints of these events in different donor categories. Borderline changes represent the most frequent histological finding early after kidney transplantation. Therefore, we examined outcomes and transcriptomic profiles of early-case biopsies diagnosed as borderline changes in different donor categories. In this single-center, retrospective, observational study, we compared midterm outcomes of kidney transplant recipients with early borderline changes as a first pathology between ECD (n = 109), standard criteria donor (SCDs, n = 109), and living donor (LD, n = 51) cohorts. Intragraft gene expression profiling by microarray was performed in part of these ECD, SCD, and LD cohorts. Although 5 year graft survival in patients with borderline changes in early-case biopsies was not influenced by donor category (log-rank P = 0.293), impaired kidney graft function (estimated glomerular filtration rate by Chronic Kidney Disease Epidemiology Collaboration equation) at M3, 1, 2, and 3 years was observed in the ECD cohort (P < 0.001). Graft biopsies from ECD donors had higher vascular intimal fibrosis and arteriolar hyalinosis compared to SCD and LD (P < 0.001), suggesting chronic vascular changes. Increased transcripts typical for ECD, as compared to both LD and SCD, showed enrichment of the inflammatory, defense, and wounding responses and the ECM-receptor interaction pathway. Additionally, increased transcripts in ECD vs. LD showed activation of complement and coagulation and cytokine-cytokine receptor pathways along with platelet activation and cell cycle regulation. Comparative gene expression overlaps of ECD, SCD, and LD using Venn diagrams found 64 up- and 16 down-regulated genes in ECD compared to both LD and SCD. Shared increased transcripts in ECD vs. both SCD and LD included thrombospondin-2 (THBS2), angiopoietin-like 4 (ANGPTL4), collagens (COL6A3, COL1A1), chemokine CCL13, and interleukin IL11, and most significantly, down-regulated transcripts included proline-rich 35 (PRR35) and fibroblast growth factor 9. Early borderline changes in ECD kidney transplantation are characterized by increased regulation of inflammation, extracellular matrix remodeling, and acute kidney injury transcripts in comparison with both LD and SCD grafts.

Project description:The significance of borderline changes (BL) in kidney allograft biopsies is widely debated. We examined differences in gene expression patterns between early clinical biopsy tissue and 3-month protocol biopsy tissue, all of which had histological BL changes and identified specific molecular BL patterns associated with poor graft outcome. The expression profiles were analyzed in training set of patients and next data were validated in validation cohort using RT-qPCR. Using the Illumina microarray technology, we observed greater expression of immunity- and inflammation-related genes in tissues from early clinical biopsies compared to 3-month protocol biopsies with BL findings. In tissues with early clinically manifested BL changes, graft deterioration within 24 months due to chronic rejection was associated with increased activation of immune, defense, and inflammatory processes, specifically with higher donor age and expression of macrophage receptor CLEC5A. In the 3-month protocol biopsies with BL changes, graft dysfunction was associated with increased expression of fibrinogen complex transcripts. This study highlights the molecular differences between clinical and subclinical biopsies with similar histological findings. The data also support a recommendation for frequent patient monitoring, especially in those who received grafts from expanded criteria donors (ECDs). The experiments were performed with total RNA derived from the renal graft biopsy samples of 28 different patients who had undergone a kidney transplantation. Only the patients with diagnosis of borderline changes early (M-bM-^IM-$2 months) or protocolar (3 months) were included in the study. RNA profiles of patients with stable and deteriorated graft function during 2 years after transplantation were compared. As microarray platform, Illumina HumanHT-12 v4.0 Expression BeadChips (Illumina) was used. The chip scanning was performed with a BeadStation 500 instrument (Illumina Inc), and the raw data were extracted with the BeadStudio Data Analysis Software (Illumina). The R software lumi package was used to further process the raw data. The quantile method was used for normalization.

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Molecular Fingerprints of Borderline Changes of Kidney Allografts is Influenced by Donor Category

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