Evaluation of vascular lesions using circulating endothelial cells in renal transplant patients

Circulating endothelial cells transiently increase in peripheral blood after kidney transplantation

The diagnosis of kidney allograft rejection is based on late histological and clinical markers. Early, specific and minimally-invasive biomarkers may improve rejection diagnosis. Endothelial cells (EC) are one of the earliest targets in kidney transplant rejection. We investigated whether circulating EC (cEC) could serve as an earlier and less invasive biomarker for allograft rejection. Blood was collected from a cohort of 51 kidney transplant recipients before and at multiple timepoints after transplantation, including during a for cause biopsy. The number and phenotype of EC was assessed by flow-cytometric analysis. Unbiased selection of EC was done using principal component (PCA) analysis. Paired analysis revealed a transient cEC increase of 2.1-fold on the third day post-transplant, recovering to preoperative levels at seventh day post-transplant and onwards. Analysis of HLA subtype demonstrated that cEC mainly originate from the recipient. cEC levels were not associated with allograft rejection, allograft function or other allograft pathologies. However, cEC in patients with allograft rejection and increased levels of cEC showed elevated levels of KIM-1 (kidney injury marker-1). These findings indicate that cEC numbers and phenotype are affected after kidney transplantation but may not improve rejection diagnosis.

Induced pluripotent stem cells attenuate chronic allogeneic vasculopathy in an integrin beta-1-dependent manner

This study aimed to determine the mechanism of isogeneic-induced pluripotent stem cells (iPSCs) homing to vascular transplants and their therapeutic effect on chronic allogeneic vasculopathy. We found that integrin β1 (Intgβ1) was the dominant integrin β unit in iPSCs that mediates the adhesion of circulatory and endothelial cells (ECs). Intgβ1 knockout or Intgβ1-siRNAs inhibit iPSC adhesion and migration across activated endothelial monolayers. The therapeutic effects of the following were examined: iPSCs, Intgβ1-knockout iPSCs, iPSCs transfected with Intgβ1-siRNAs or nontargeting siRNAs, iPSC-derived ECs, iPSC-derived ECs simultaneously overexpressing Intgα4 and Intgβ1, iPSCs precultured in endothelial medium for 3 days (endothelial-prone stem cells), primary aortic ECs, mouse embryonic fibroblasts, and phosphate-buffered saline (control). The cells were administered every 3 days for a period of 8 weeks. iPSCs, iPSCs transfected with nontargeting siRNAs, and endothelial-prone stem cells selectively homed on the luminal surface of the allografts, differentiated into ECs, and decreased neointimal proliferation. Through a single administration, we found that iPSCs trafficked to allograft lesions, differentiated into ECs within 1 week, and survived for 4-8 weeks. The therapeutic effect of a single administration was moderate. Thus, Intgβ1 and pluripotency are essential for iPSCs to treat allogeneic vasculopathy.

Fluorescence detection, enumeration and characterization of single circulating cells in vivo: technology, applications and future prospects

There are many diseases and biological processes that involve circulating cells in the bloodstream, such as cancer metastasis, immunology, reproductive medicine, and stem cell therapies. This has driven significant interest in new technologies for the study of circulating cells in small animal research models and clinically. Most currently used methods require drawing and enriching blood samples from the body, but these suffer from a number of limitations. In contrast, 'in vivo flow cytometry' (IVFC) refers to set of technologies that allow study of cells directly in the bloodstream of the organism in vivo. In recent years the IVFC field has grown significantly and new techniques have been developed, including fluorescence microscopy, multi-photon, photo-acoustic, and diffuse fluorescence IVFC. In this paper we review recent technical advances in IVFC, with emphasis on instrumentation, contrast mechanisms, and detection sensitivity. We also describe key applications in biomedical research, including cancer research and immunology. Last, we discuss future directions for IVFC, as well as prospects for broader adoption by the biomedical research community and translation to humans clinically.

Association of miRNA-145 expression in vascular smooth muscle cells with vascular damages in patients with lupus nephritis

miRNAs have been found to contribute to the regulation of multiple cellular processes, including cell apoptosis, differentiation and proliferation. The patients with lupus nephritis (LN) exhibit thickened renal vascular membrane and highly proliferative vascular smooth muscle cells (VSMCs). Of various miRNAs discovered, miR-145 is essential to mediate the proliferation of VSMCs and the formation of atherosclerotic plaques. In this study, we studied the pathological and vascular damage of renal LN, and the correlation between miR-145 expression in VSMCs and the vascular damages. Serum, urine, and renal biopsies were obtained from 41 patients with active LN. The serum and urinary VEGF levels were examined to confirm the renal damage of each patient. Biopsies were stained to observe the glomerular segmental lesions, sclerosis, and to evaluate the vascular damages. The expression of miR-145 was also examined to determine the correlation between its expression and the vascular damages. The expression of miR-145 was mainly detected in the renal VSMCs and the epithelial cells of glomerular proximal convoluted tubule. Nevertheless, the expression of miR-145 reduced as the tunicae media vasorum ratios increased, indicating the development of LN inhibits the expression of miR-145. Furthermore, our studies revealed no significant correlation among renal interstitial vascular damage, glomerular damage and severity classification of LN. Therefore, we suggest the damage of renal interstitial vascular should be considered as one of the factors to evaluate the severity of the LN.

Evaluation of endothelial damage in sepsis-related ARDS using circulating endothelial cells

PURPOSE

Endothelial cell activation and dysfunction are involved in the pathophysiology of ARDS. Circulating endothelial cells (CECs) may be a useful marker of endothelial dysfunction and damage but have been poorly studied in ARDS. We hypothesized that the CEC count may be elevated in patients with sepsis-related ARDS compared to those with sepsis without ARDS.

METHODS

ARDS was defined according to the Berlin consensus definition. The study population included 17 patients with moderate or severe ARDS, 9 with mild ARDS, 13 with sepsis and no ARDS, 13 non-septic patients, and 12 healthy volunteers. Demographic, hemodynamic, and prognostic variables, including PaO(2)/FiO(2) ratio, 28-day survival, blood lactate, APACHE II, and SOFA score, were recorded. CECs were counted in arterial blood samples using the reference CD146 antibody-based immunomagnetic isolation and UEA1-FITC staining method. Measurements were performed 12-24 h after diagnosis of ARDS and repeated daily for 3 days.

RESULTS

The median day-1 CEC count was significantly higher in patients with moderate or severe ARDS than in mild ARDS or septic-control patients [27.2 (18.3-49.4) vs. 17.4 (11-24.5) cells/ml (p < 0.034), and 18.4 (9.1-31) cells/ml (p < 0.035), respectively]. All septic patients (with or without ARDS) had higher day-1 CEC counts than the non-septic patients [19.6 (14.2-30.6) vs. 10.8 (5.7-13.2) cells/ml, p = 0.002].

CONCLUSION

The day-1 CEC count was significantly higher in ARDS patients than in other critically ill patients, and in moderate or severe ARDS patients compared to those with milder disease, making it a potentially useful marker of ARDS severity.

Clinical and ethical considerations of massively parallel sequencing in transplantation science

Massively parallel sequencing (MPS), alias next-generation sequencing, is making its way from research laboratories into applied sciences and clinics. MPS is a framework of experimental procedures which offer possibilities for genome research and genetics which could only be dreamed of until around 2005 when these technologies became available. Sequencing of a transcriptome, exome, even entire genomes is now possible within a time frame and precision that we could only hope for 10 years ago. Linking other experimental procedures with MPS enables researchers to study secondary DNA modifications across the entire genome, and protein binding sites, to name a few applications. How the advancements of sequencing technologies can contribute to transplantation science is subject of this discussion: immediate applications are in graft matching via human leukocyte antigen sequencing, as part of systems biology approaches which shed light on gene expression processes during immune response, as biomarkers of graft rejection, and to explore changes of microbiomes as a result of transplantation. Of considerable importance is the socio-ethical aspect of data ownership, privacy, informed consent, and result report to the study participant. While the technology is advancing rapidly, legislation is lagging behind due to the globalisation of data requisition, banking and sharing.