The value of microparticles in detecting acute rejection episodes after liver transplantation.

CONTEXT: Non-invasive markers for diagnosis of acute rejection (AR) following liver transplantation have not been developed, yet. OBJECTIVE: We analyzed the correlation of plasma microparticle levels (MP) with AR. MATERIALS AND METHODS: MP (CD4, CD8, CD25, CD31, MHC) of 11 AR patients and 11 controls were analyzed within the first week after transplantation. RESULTS: CD4, CD8 and CD31 positive MP were higher in the AR, whereas overall MP count, CD25 and MHCI positive MP proportions did not differ between both groups. DISCUSSION AND CONCLUSION: MP dynamics within the first period of transplantation could help to clarify on-going mechanisms of immunomodulation.

Dysregulation of urinary miR-21 and miR-200b associated with interstitial fibrosis and tubular atrophy (IFTA) in renal transplant recipients.

OBJECTIVE: microRNAs (miRNAs) are endogenous gene expression regulators that are involved in renal function and physiopathology, making them potential biomarkers in the realm of transplantation. Here, we aimed to evaluate urinary miRNA expression levels and assess their possible values in the prospective evaluation of renal allograft function. DESIGN AND METHODS: The expression levels of four miRNAs involved in renal fibrosis were quantified in urine cell pellets of 47 kidney recipients (with stable allograft function (SGF) and biopsy proven interstitial fibrosis and tubular atrophy; IFTA) and 15 healthy controls by real-time quantitative-PCR (RT-qPCR). The hierarchical clustering and receiver operating characteristic (ROC) analysis of miRNAs were performed in the study groups. RESULTS: Significant differences were observed in the urinary expression of miR-21 (P<0.001), miR-142-3p (P<0.001), and miR-200b (P=0.021) between IFTA and controls. The hierarchical clustering of miRNA expression clustered most of the SGF and IFTA patients in separated groups. Estimated GFR was significantly correlated with urinary levels of miR-21 (r=0.585, P=0.003) and miR-200 (r=-0.447, P=0.033). ROC analysis confirmed the ability of urinary miR-21 and miR-200b to discriminate the IFTA recipients with an area under the ROC curve of ≥0.81 (P<0.001) and high sensitivity and specificity. CONCLUSION: Taken together, our findings indicated that the aberrant urinary miR-21 and miR-200b expression levels were accompanied with renal allograft dysfunction and IFTA. Therefore, they can be considered as potential diagnostic biomarkers for renal allograft monitoring.

Bioluminescence tracking of alginate micro-encapsulated cell transplants.

Cell-based therapies to treat loss-of-function hormonal disorders such as diabetes and Parkinson's disease are routinely coupled with encapsulation strategies, but an understanding of when and why grafts fail in vivo is lacking. Consequently, investigators cannot clearly define the key factors that influence graft success. Although bioluminescence is a popular method to track the survival of free cells transplanted in preclinical models, little is known of the ability to use bioluminescence for real-time tracking of microencapsulated cells. Furthermore, the impact that dynamic imaging distances may have, due to freely-floating microcapsules in vivo, on cell survival monitoring is unknown. This work addresses these questions by applying bioluminescence to a pancreatic substitute based on microencapsulated cells. Recombinant insulin-secreting cells were transduced with a luciferase lentivirus and microencapsulated in Ba2+ crosslinked alginate for in vitro and in vivo studies. In vitro quantitative bioluminescence monitoring was possible and viable microencapsulated cells were followed in real time under both normoxic and anoxic conditions. Although in vivo dispersion of freely-floating microcapsules in the peritoneal cavity limited the analysis to a qualitative bioluminescence evaluation, signals consistently four orders of magnitude above background were clear indicators of temporal cell survival. Strong agreement between in vivo and in vitro cell proliferation over time was discovered by making direct bioluminescence comparisons between explanted microcapsules and parallel in vitro cultures. Broader application of this bioluminescence approach to retrievable transplants, in supplement to currently used end-point physiological tests, could improve understanding and accelerate development of cell-based therapies for critical clinical applications. Copyright © 2014 John Wiley & Sons, Ltd.

Advances in diagnostics for transplant rejection.

INTRODUCTION: Identification of allograft injury, including acute clinical and subclinical injury, is vital in increasing the longevity of the transplanted organ. Acute rejection, which occurs as a result of a variety of immune and non-immune factors including the infiltration of immune cells and antibodies to the donor specific epitopes, poses a significant risk to the organ. Recent years have marked an increase in the discovery of new genomic, transcriptomic, and proteomic biomarkers in molecular diagnostics, which offer better potential for personalized management of the transplanted organ by providing earlier detection of rejection episodes. Areas covered: This review was compiled from key word searches of full-text publications relevant to the field. Expert commentary: Many of the recent advancements in the molecular diagnostics of allograft injury show much promise, but before they can be fully realized further validation in larger sample sets must be conducted. Additionally, for better informed therapeutic decisions, more work must be completed to differentiate between different causes of injury. Moreover, the diagnostics field is looking at methodologies that allow for multiplexing, the ability to identify multiple targets simultaneously, in order to provide more robust biomarkers and better understanding.