Ihdina Sukma Dewi

Altered serum miRNA profiles during acute rejection after heart transplantation: Potential for non-invasive allograft surveillance

interstitial edema were more frequent in the TBI and PE groups than in the hanging group. In the LV, hypereosinophilia and interstitial edema were more frequent in the TBI and PE groups compared with the hanging group. The other signs were similarly observed in the three groups (Table 1). In the RV, positive reaction against fibronectin was more frequent in the TBI (80.9%) and PE (100%) groups compared with the hanging group (47.6%, p o 0.05 and p o 0.01) and was more frequent in the PT than in the TBI group (p o 0.05). A positive reaction against C5b-9 was more frequent in the TBI (28.6%) and PT (36.9%) groups than in the hanging group, in which no positive cases were observed (p o 0.05 and p o 0.01). The difference between the TBI and PE groups did not reach statistical significance. In the LV, positive reaction against fibronectin was more frequent in the PE group (73.7%) than in the TBI and hanging groups (33.3% and 42.9%), but this difference was not statistically significant. Overall, C5b-9 was positive in only 1 case from the TBI group. The IHC findings are summarized in Figure 1. Figure 2 shows the IHC expression of the antibodies used. To our knowledge, this is the first study to demonstrate an increased expression of fibronectin and C5b-9 in the RV after fatal TBI, indicating fresh cardiac ischemic lesions, similar to those observed after fatal PE. We may postulate that, after a severe TBI, the RV undergoes ischemic stress resulting from a sudden pressure overload due to catecholamine-mediated, acutely raised PAP. We propose that such a mechanism may play (beside direct catecholamine toxicity) an important role in damage of the RV myocardium. This may partly explain the RV dysfunction often observed in heart transplant recipients when donors were victims of TBI. Our findings suggest that invasive monitoring of PAP and PH-targeted therapies may improve the number and the quality of donor hearts, thereby improving transplantation rates and outcomes. Similar to most of the morphologic studies on autopsy material, we have presented a snapshot of the investigated pathologies, but have not presented clinical ‘‘dynamic’’ evidence. Another potential limitation is that the differences in baseline characteristics of the victims may partly explain the results.

Exosomal miR-142-3p is increased during cardiac allograft rejection and augments vascular permeability through down-regulation of endothelial RAB11FIP2 expression.

Aims Exosome-mediated microRNA transfer is a recently discovered mode of cell-to-cell communication, in which microRNAs act as paracrine molecules, exerting their regulatory effects in recipient cells. T cells and endothelial cells are two main players in the mechanism of acute cellular cardiac rejection. The aim of this study was to investigate the role of exosomal microRNAs in the crosstalk between T cells and endothelial cells and its implications for the molecular mechanisms that drive acute cellular rejection in heart transplantation. Methods and results Exosomes isolated from serum samples of heart transplant patients with and without acute cardiac allograft rejection were profiled and showed enrichment of miR-142-3p, miR-92a-3p, miR-339-3p and miR-21-5p. Treatment of endothelial cells with the respected serum exosomes resulted the increased of miR-142-3p level in endothelial cells. Using T cells isolated from healthy donors and activated with either anti-CD3/CD28 antibody or IL-2/PHA, we could show that miR-142-3p is released from activated cells, is contained in exosomes and can be transferred to human vascular endothelial cells in vitro. Transcriptome analysis of endothelial cells treated with activated T cell supernatant with or without exosomes was used to identify mRNA targets of transferred miR-142-3-p. Overexpression of miR-142-3p in endothelial cells resulted in a significant down-regulation of RAB11FIP2, and interaction of miR-142-3p with its predicted target site was confirmed with a reporter assay. Moreover, treatment of endothelial cells with serum exosomes from heart transplant patients with acute cellular rejection resulted in down-regulation of RAB11FIP2 expression and increase in vascular endothelial permeability. Conclusion We have identified a novel mechanism whereby miR-142-3p, a microRNA enriched in exosomes during acute cellular rejection, is transferred to endothelial cells and compromises endothelial barrier function via down-regulation of RAB11FIP2. This study sheds new light on the interaction between host immune system and cardiac allograft endothelium during acute cellular rejection.

Association of serum MiR-142-3p and MiR-101-3p levels with acute cellular rejection after heart transplantation

Background Identifying non-invasive and reliable blood-derived biomarkers for early detection of acute cellular rejection in heart transplant recipients is of great importance in clinical practice. MicroRNAs are small molecules found to be stable in serum and their expression patterns reflect both physiological and underlying pathological conditions in human. Methods We compared a group of heart transplant recipients with histologically-verified acute cellular rejection (ACR, n = 26) with a control group of heart transplant recipients without allograft rejection (NR, n = 37) by assessing the levels of a select set of microRNAs in serum specimens. Results The levels of seven microRNAs, miR-142-3p, miR-101-3p, miR-424-5p, miR-27a-3p, miR-144-3p, miR-339-3p and miR-326 were significantly higher in ACR group compared to the control group and could discriminate between patients with and without allograft rejection. MiR-142-3p and miR-101-3p had the best diagnostic test performance among the microRNAs tested. Serum levels of miR-142-3p and miR-101-3p were independent of calcineurin inhibitor levels, as measured by tacrolimus and cyclosporin; kidney function, as measured by creatinine level, and general inflammation state, as measured by CRP level. Conclusion This study demonstrated two microRNAs, miR-142-3p and miR-101-3p, that could be relevant as non-invasive diagnostic tools for identifying heart transplant patients with acute cellular rejection.

HEARTBIT: A Novel Biosignature for Detection of Acute Cellular Rejection of Heart Allografts

Background Acute cellular allograft rejection remains a major cause of limited long-term graft survival in cardiac transplantation. A critical challenge in trying to reduce the incidence of acute cellular rejection arises from the difficulty of accurately and efficiently making diagnoses. The primary approach requires taking small pieces of heart muscle tissue, which is highly invasive and costly, and suffers from sampling error and inter-observer grading variability. Replacing the biopsy with a simple blood test would be of great value to patients and substantially reduce healthcare costs. Approach and Methods We previously used high-throughput, untargeted transcriptomic profiling in blood samples of heart transplant patients to identify 9 mRNAs and 5 proteins whose combined expression discriminated patients undergoing acute cellular rejection from those who were not. We now validated the mRNA targets on a clinically-amenable NanoString nCounter platform. The performance of the novel assay, HEARTBIT, as well as that of a proteogenomic ensemble including 5 proteins, was assessed by cross-validation. Results In cross-validation the area under the receiver operating characteristic curve (AUC) of the transcriptomic signature was 0.81, with 47% specificity at ≥ 90% sensitivity. Addition of 5 proteins to the mRNA panel using ensembling resulted in an enhanced performance (AUC of 0.86, with 65% specificity at ≥ 90% sensitivity, in cross-validation). Summary and Conclusion Here, we demonstrate 1) successful translation of biomarker signatures from untargeted high-throughput screening onto a compact, clinically-amenable technological platform, and 2) promising utility of our novel assay, HEARTBIT, for improved detection of acute cellular rejection.

P2×7 RECEPTOR INHIBITION ATTENUATES HUMAN MACROPHAGE RESPONSE TO OXIDIZED LOW-DENSITY LIPOPROTEIN

The P2×7 receptor has recently been suggested to play a role in macrophage function. In addition, novel inhibitors of this receptor have been developed for treatment of rheumatoid arthritis because of their anti-inflammatory properties. Atherosclerosis is an inflammatory disease of the