DNA in extracellular vesicles: from evolution to its current application in health and disease.

Extracellular vesicle (EV) secretion is a highly conserved evolutionary trait in all organisms in the three domains of life. The packaging and release of EVs appears to be a bulk-flow process which takes place mainly under extreme conditions. EVs participate in horizontal gene transfer, which supports the survival of prokaryotic and eukaryotic microbes. In higher eukaryotes, almost all cells secrete a heterogeneous population of EVs loaded with various biomolecules. EV secretion is typically higher in cancer microenvironments, promoting tumor progression and metastasis. EVs are now recognized as additional mediators of autocrine and paracrine communication in health and disease. In this context, proteins and RNAs have been studied the most, but extracellular vesicle DNA (EV-DNA) has started to gain in importance in the last few years. In this review, we summarize new findings related to the loading mechanism(s), localization, and post-shedding function of EV-DNA. We also discuss the feasibility of using EV-DNA as a biomarker when performing a liquid biopsy, at the same time emphasizing the lack of data from clinical trials in this regard. Finally, we outline the potential of EV-DNA uptake and its interaction with the host genome as a promising tool for understanding the mechanisms of cancer evolution.

Protocol liver biopsies in stable long-term pediatric liver transplant recipients: risk or benefit?

BACKGROUND: Follow-up after pediatric liver transplantation (LTX) is challenging and needs to be refined to extend graft survival as well as general functional health and patients´ quality of life. Strategies towards individual immunosuppressive therapy seem to play a key role. Our aim was to evaluate protocol liver biopsies (PLB) as a tool in personalized follow up after pediatric LTX. PATIENTS AND METHODS: Our retrospective analysis evaluates 92 PLB in clinically asymptomatic pediatric patients after LTX between 2009 and 2019. Histological findings were characterized using the Desmet scoring system. In addition to PLB, other follow-up tools like laboratory parameters, ultrasound imaging and transient elastography were evaluated. Risk factors for development of fibrosis or inflammation were analyzed. RESULTS: PLB revealed a high prevalence of graft fibrosis (67.4%) and graft inflammation (47.8%). Graft inflammation was significantly (P = 0.0353*) more frequent within the first 5 years after transplantation compared to later time points. Besides conventional ultrasound, the measurement of liver stiffness using transient elastography correlate with stage of fibrosis (r = 0.567, P = <0.0001***). Presence of donor-specific anti-human leukocyte antigen antibodies in blood correlates with grade of inflammation in PLB (r = 0.6040, P = 0.0018 **). None of the patients who underwent PLB suffered from intervention-related complications. Histopathological results had an impact on clinical decision making in one-third of all patients after PLB. CONCLUSION: PLB are a safe and useful tool to detect silent immune-mediated allograft injuries in the context of normal liver parameters.

Kidney transplantation with allografts from infant donors-Small organs, big value.

BACKGROUND: Although infant organ donors remain a rare source of organs for transplantation, technical challenges have resulted in increased rates of complications and inferior graft function. The aim of the present study was to investigate the outcomes of kidneys procured from juvenile and infant donors. PATIENTS AND METHODS: We evaluated all kidney transplants from deceased donors < 16 years of age performed at our center between 01/2008 and 08/2019. We defined three groups based on quartiles of donor body weight: <13 kg (infant donors), 13-40 kg (juvenile donors), and > 40 kg (standard criteria donors). Clinical characteristics and outcomes were compared between groups. RESULTS: Ninety-two transplants were included in this study. Out of 92 recipients, there were 32 (34.8%) adult and 60 (65.2%) pediatric patients. All groups demonstrated excellent graft function and survival on both short and long-term follow-up. 1-year, 3-year, and 5-year graft survival rates for the standard criteria donor group were 100%, 95.2%, and 88.4%, respectively, compared with 95.8% for infant and 95% for juvenile donors at all times (P = .79). eGFR at 5 years was 98.9 ± 5.5, 74.1 ± 6.2, and 81.6 ± 6.9 mL/min/1.73 m2 for infant, juvenile, and standard criteria donors, respectively (P < .01). CONCLUSION: Infant donor allografts can be transplanted with excellent long-term outcomes in both pediatric and adult recipients. Implanting them as single allografts onto pediatric candidates allows for the transplantation of two patients. As such, pediatric recipients should be prioritized for these donor organs.

The mTOR pathway is activated in human autosomal-recessive polycystic kidney disease.

BACKGROUND: An inappropriate activation of the mTOR pathway was demonstrated in the autosomal dominant (AD) form of polycystic kidney disease (PKD). To date it is unclear whether the mTOR pathway is activated in autosomal-recessive (AR) PKD, a cystic disease which occurs in childhood. The purpose of the present study was to evaluate the mTOR pathway in AR PKD. METHODS: We evaluated the expression of mTOR pathway molecules in paraffin-embedded liver and kidney samples from patients with AR PKD and control specimens from animals as well as humans. Monoclonal antibodies, the phosphorylated proteins pmTOR, pS6-ribosomal-protein (pS6K), p4E-BP1, peIF4G, and phospho-tuberin/TSC2 were used. RESULTS: mTOR was strongly expressed in renal cyst-lining cells and bile ducts from AR PKD specimen. S6K immunostaining was strong in smaller tubules and weak both in larger renal cysts and in the bile duct epithelium. In controls, mTOR and S6K were expressed in distal tubule segments. 4E-BP1-immunostaining was restricted to noncystic tubules in AR PKD. eIFG4-immunostaining was observed in bile duct epithelium in AR PKD, but not in control tissue. Tuberin/TSC2 immunostaining was negative in all specimens. CONCLUSION: Our data suggest that the mTOR pathway may be activated in AR PKD, and mTOR molecules may represent a potential target to slow down cyst development in this disease.

Multicenter trial of everolimus in pediatric renal transplant recipients: results at three year.

There are few prospective clinical trials of mTOR inhibitors (or proliferation signal inhibitors) combined with CNI inhibitors in de novo pediatric renal transplantation. Results reported here are from a multicenter, open-label study in de novo pediatric renal transplant patients (