Sphingolipid composition of circulating extracellular vesicles after myocardial ischemia.

Sphingolipids are structural components of cell membrane, displaying several functions in cell signalling. Extracellular vesicles (EV) are lipid bilayer membrane nanoparticle and their lipid composition may be different from parental cells, with a significant enrichment in sphingolipid species, especially in pathological conditions. We aimed at optimizing EV isolation from plasma and describing the differential lipid content of EV, as compared to whole plasma. As pilot study, we evaluated the diagnostic potential of lipidomic signature of circulating EV in patients with a diagnosis of ST-segment-elevation myocardial infarction (STEMI). STEMI patients were evaluated before reperfusion and 24-h after primary percutaneous coronary intervention. Twenty sphingolipid species were quantified by liquid-chromatography tandem-mass-spectrometry. EV-ceramides, -dihydroceramides, and -sphingomyelins increased in STEMI vs. matched controls and decreased after reperfusion. Their levels correlated to hs-troponin, leucocyte count, and ejection fraction. Plasma sphingolipids levels were 500-to-700-fold higher as compared to EV content; nevertheless, only sphingomyelins differed in STEMI vs. control patients. Different sphingolipid species were enriched in EV and their linear combination by machine learning algorithms accurately classified STEMI patients at pre-PCI evaluation. In conclusion, EV lipid signature discriminates STEMI patients. These findings may contribute to the identification of novel biomarkers and signaling mechanisms related to cardiac ischemia.

Young@Heart: empowering the next generation of cardiovascular researchers.

In recognition of the increasing health burden of cardiovascular disease, the Dutch CardioVascular Alliance (DCVA) was founded with the ambition to lower the cardiovascular disease burden by 25% in 2030. To achieve this, the DCVA is a platform for all stakeholders in the cardiovascular field to align policies, agendas and research. An important goal of the DCVA is to guide and encourage young researchers at an early stage of their careers in order to help them overcome challenges and reach their full potential. Young@Heart is part of the DCVA that supports the young cardiovascular research community. This article illustrates the challenges and opportunities encountered by young cardiovascular researchers in the Netherlands and highlights Young@Heart's vision to benefit from these opportunities and optimise collaborations to contribute to lowering the cardiovascular disease burden together as soon as possible.

Fetal and perinatal stem cells in cardiac regeneration: Moving forward to the paracrine era.

Cardiovascular disease (CD) is a major burden for Western society. Regenerative medicine has provided encouraging results, yet it has not addressed the focal defects causing CD and mainly related to the inefficient repair programme of the heart. In this scenario, stem cells have been broadly investigated and their paracrine effect proposed as a possible working strategy to boost endogenous mechanisms of repair and regeneration from within the cardiac tissue. The scientific community is now focusing on identifying the most effective stem cell secretome, as the whole of bioactive factors and extracellular vesicles secreted by stem cells and endowed with regenerative potential. Indeed, the adult stem cell-paracrine potential for cardiac regeneration have been widely analyzed with positive outcome. Nevertheless, low yield, invasive sampling and controversial self-renewal may limit adult stem cell application. On the contrary, fetal and perinatal stem cells, which can be easily isolated from leftover sample via prenatal screening during gestation or as clinical waste material after birth, can offer an ideal alternative. These broadly multipotent immature progenitors share features with both adult and embryonic stem cells, show high self-renewal, but they are not tumorigenic neither cause any ethical concern. While fetal and perinatal stem cells demonstrated to improve cardiac function when injected in the injured heart, the comprehensive characterization of their secretome for future applications is still at its infancy. In this review, we will discuss the paracrine potential of the fetal and perinatal stem cell secretome to provide cardiac repair and resurge the dormant mechanisms of cardiac regeneration for future therapy.

Surgical complications in 2000 renal transplants.

INTRODUCTION: Renal transplantation is the best treatment for end-stage renal disease. In the last years, we have seen improvements in immunosuppressive treatment, which have allowed patients to experience a better quality of life and graft survival. Nevertheless, surgical complications remain important problems that increase morbidity, mortality, costs, and hospitalization. Our purpose was to evaluate surgical complications among a large series of 2000 renal transplantations. PATIENTS AND METHODS: We retrospectively analyzed all surgical complications among 2000 renal transplants performed between June 1980 and March 2010 in our department. RESULTS: Among 318 (15.9%) surgical complications, 4.8% of patients had urologic problems. Ureteral stenosis and fistula, stent obstruction, and ureteral necrosis occurred in 2.7%, 1.8%, 0.1%, and 0.2% of patients, respectively. Vascular complications reported in 2.7% of patients included arterial or venous thrombosis (1.0% or 0.4%), both arterial and venous thrombosis (0.1%), renal infarction (0.1%), renal artery aneurysm (0.1%) as well as arterial stenosis (0.5%), kinking (0.4%), or dissection (0.1%). Other complications, not specifically related with transplantation surgery, occurred in 4.4% of patients. CONCLUSION: Renal transplantation is a safe surgery by experienced teams. Our rates of surgical complications were within those reported by other series. A meticulous surgical technique is mandatory to prevent them. Prompt diagnosis and management are required to prevent graft damage and patient morbidity.

Human bone marrow-derived CD133(+) cells delivered to a collagen patch on cryoinjured rat heart promote angiogenesis and arteriogenesis.

Transplanting hematopoietic and peripheral blood-derived stem/progenitor cells can have beneficial effects in slowing the effects of heart failure. We investigated whether human bone marrow CD133(+)-derived cells (BM-CD133(+) cells) might be used for cell therapy of heart injury in combination with tissue engineering. We examined these cells for: 1) their in vitro capacity to be converted into cardiomyocytes (CMs), and 2) their potential for in vivo differentiation when delivered to a tissue-engineered type I collagen patch placed on injured hearts (group II). To ensure a microvascular network ready for use by the transplanted cells, cardiac injury and patching were scheduled 2 weeks before cell injection. The cardiovascular potential of the BM-CD133(+) cells was compared with that of a direct injection (group I) of the same cells in heart tissue damaged according to the same schedule as for group II. While a small fraction (2 ± 0.5%) of BM-CD133(+)cells cocultured with rat CMs switched in vitro to a CM-like cell phenotype, in vivo-and in both groups of nude rats transplanted with BM-CD133(+)--there was no evidence of any CM differentiation (as detected by cardiac troponin I expression), but there were signs instead of new capillaries and small arterioles. While capillaries prevailed over arterioles in group II, the opposite occurred in group I. The transplanted cells further contributed to the formation of new microvessels induced by the patch (group II) but the number of vessels did not appear superior to the one developed after directly injecting the BM-CD133(+)cells into the injured heart. Although chimeric human-rat microvessels were consistently found in the hearts of both groups I and II, they represented a minority (1.5-2.3%) compared with those of rat origin. Smooth muscle myosin isoform expression suggested that the arterioles achieved complete differentiation irrespective of the presence or absence of the collagen patch. These findings suggest that: 1) BM-CD133(+) cells display a limited propensity for in vitro conversion to CMs; 2) the preliminarily vascularized bioscaffold did not confer a selective homing and differentiation advantage for the phenotypic conversion of BM-CD133(+) cells into CMs; and 3) combined patching and cell transplantation is suitable for angiogenesis and arteriogenesis, but it does not produce better results, in terms of endothelial and smooth muscle cell differentiation, than the "traditional" method of cell injection into the myocardium.

High-throughput fluorescence polarization method for identification of FKBP12 ligands.

FKBP12 is best known as the target of the widely used immunosuppressive drug FK506 but may also play a role in neuronal survival. Nonimmunosuppressive ligands of FKBP12 have been shown to have neuroprotective and neuroregenerative activity both in vitro and in vivo, stimulating interest in the development of high-throughput screens to rapidly identify novel ligands. FKBP12 was expressed as a His(6)-fusion in bacteria and purified by metal ion affinity and gel filtration chromatography. A high-throughput fluorescence polarization assay was developed to identify novel ligands of FKBP12. Dissociation constant values of known FKBP12 ligands measured by the new method agreed closely with K(i) values obtained by assaying inhibition of the rotamase activity of the enzyme. The fluorescence polarization assay is rapid, robust, and inexpensive and does not generate radioactive waste. It is very well suited for high-throughput screening efforts.

2-Aryl-2,2-difluoroacetamide FKBP12 ligands: synthesis and X-ray structural studies.

[structure: see text] 2-Aryl-2,2-difluoroacetamido-proline and pipecolate esters are high affinity FKBP12 ligands whose rotamase inhibitory activity is comparable to that seen for the corresponding ketoamides. X-ray structural studies suggest that the fluorine atoms participate in discrete interactions with the Phe36 phenyl ring and the Tyr26 hydroxyl group, with the latter resembling a moderate-to-weak hydrogen bond.

Fluoresceinated FKBP12 ligands for a high-throughput fluorescence polarization assay.

Several fluoresceinated FKBP12 ligands have been prepared for a high-throughput fluorescence polarization assay. K(i)s for FKBP12 rotamase inhibition by these ligands range from 1.3 microM to 32 nM, and their design is based on X-ray crystal structures of FKBP12 complexed with known immunophilin ligands.