A possible case of Langerhans-cell histiocytosis? Differential diagnosis in a rare case from the Late Antiquity Bavaria (Germany).

OBJECTIVE: To outline the importance of accurate diagnosis in ancient rare diseases by presenting a possible case of Langerhans-cell histiocytosis. MATERIALS: Skeletal elements from a well-preserved skeleton of a nine to eleven-year-old, probably female child who lived around 300-400 AD Late Roman Neuburg / Donau (Germany). METHODS: Macroscopic, radiologic, light and scanning-electron microscopic and physical techniques were used. RESULTS: Resorptive defects, particularly in the cranium, but also in the left hip bone and the right femur, suggest the presence of Langerhans-cell histiocytosis macroscopically and radiologically. The presence of morphological changes along the edges of osteolytic lesions and in the diploic spaces appear to be post-mortem artifacts based on microscopic investigation and elemental analysis. CONCLUSIONS: Re-evaluation of morphological structures and elemental constitution of lesions is critical to differential diagnosis. In the case examined here, the identification of post-mortem structures rules out the former diagnosis of Langerhans-cell histiocytosis. Re-evaluation of cases of rare diseases require applying a range of methods during the analysis, as every single case makes a difference in the numbers of this very small group of diseases. SIGNIFICANCE: This study emphasizes the importance of utilizing different analytical techniques to avoid false diagnoses. LIMITATIONS: Not all morphological features can reliably be diagnosed using microscopic and elemental techniques. SUGGESTIONS FOR FURTHER RESEARCH: In the case of rare diseases that are difficult to diagnose, the widest possible spectrum of techniques should always be used, particularly microscopy.

Impact of eNOS-Dependent Oxidative Stress on Endothelial Function and Neointima Formation.

AIMS: Vascular oxidative stress generated by endothelial NO synthase (eNOS) was observed in experimental and clinical cardiovascular disease, but its relative importance for vascular pathologies is unclear. We investigated the impact of eNOS-dependent vascular oxidative stress on endothelial function and on neointimal hyperplasia. RESULTS: A dimer-destabilized mutant of bovine eNOS where cysteine 101 was replaced by alanine was cloned and introduced into an eNOS-deficient mouse strain (eNOS-KO) in an endothelial-specific manner. Destabilization of mutant eNOS in cells and eNOS-KO was confirmed by the reduced dimer/monomer ratio. Purified mutant eNOS and transfected cells generated less citrulline and NO, respectively, while superoxide generation was enhanced. In eNOS-KO, introduction of mutant eNOS caused a 2.3-3.7-fold increase in superoxide and peroxynitrite formation in the aorta and myocardium. This was completely blunted by an NOS inhibitor. Nevertheless, expression of mutant eNOS in eNOS-KO completely restored maximal aortic endothelium-dependent relaxation to acetylcholine. Neointimal hyperplasia induced by carotid binding was much larger in eNOS-KO than in mutant eNOS-KO and C57BL/6, while the latter strains showed comparable hyperplasia. Likewise, vascular remodeling was blunted in eNOS-KO only. INNOVATION: Our results provide the first in vivo evidence that eNOS-dependent oxidative stress is unlikely to be an initial cause of impaired endothelium-dependent vasodilation and/or a pathologic factor promoting intimal hyperplasia. These findings highlight the importance of other sources of vascular oxidative stress in cardiovascular disease. CONCLUSION: eNOS-dependent oxidative stress is unlikely to induce functional vascular damage as long as concomitant generation of NO is preserved. This underlines the importance of current and new therapeutic strategies in improving endothelial NO generation.

TNF-α alters the release and transfer of microparticle-encapsulated miRNAs from endothelial cells.

MicroRNAs (miRNAs) encapsulated within microparticles (MPs) are likely to have a role in cell-to-cell signaling in a variety of diseases, including atherosclerosis. However, little is known about the mechanisms by which different cell types release and transfer miRNAs. Here, we examined TNF-α-induced release of MP-encapsulated miR-126, miR-21, and miR-155 from human aortic endothelial cells (ECs) and their transfer to recipient cells. ECs were treated with TNF-α (100 ng/ml) in the presence or absence of inhibitors that target different MP production pathways. MPs released in response to TNF-α were characterized by: 1) 70-80% decrease in miRNA/MP levels for miR-126 and -21 but a significant increase in pre-miR-155 and miR-155 (P < 0.05), 2) 50% reduction in uptake by recipient cells (P < 0.05), and 3) diminished ability to transfer miRNA to recipient cells. Cotreatment of donor ECs with TNF-α and caspase inhibitor (Q-VD-OPH, 10 µM) produced MPs that had: 1) 1.5- to 2-fold increase in miRNA/MP loading, 2) enhanced uptake by recipient cells (2-fold), and 3) increased ability to transfer miR-155. Cotreatment of ECs with TNF-α and Rho-associated kinase (ROCK) inhibitor (10 µM) produced MPs with features similar to those produced by TNF-α treatment alone. Our data indicate that TNF-α induced the production of distinct MP populations: ROCK-dependent, miRNA-rich MPs that effectively transferred their cargo and were antiapoptotic, and caspase-dependent, miRNA-poor MPs that were proapoptotic. These data provide insight into the relationship between MP production and extracellular release of miRNA, as well as the potential of encapsulated miRNA for cell-to-cell communication.

Sustained liver regeneration after portal vein embolization --a human molecular pilot study.

BACKGROUND: Portal vein embolization is a treatment option to achieve a sufficient future remnant liver volume for patients with central liver tumours requiring an extended resection with an extensive parenchymal loss. However, molecular mechanisms of this intervention are up to now poorly understood. The objective of this prospective pilot study was the characterization of molecular events leading to late hypertrophy of the non-embolized liver tissue in the human liver. METHODS: Liver tissue of ten patients was collected before and intraoperatively more than one month after embolization. Investigation of molecular features was performed by pangenomic chips, polymerase chain reaction, immunostaining of proliferation marker Ki-67 and immunofluorescence measurements. RESULTS: Significantly elevated genes hint towards angiogenesis and signalling by insulin-like growth factor and associated binding proteins. Increased transcript levels of activator protein 1 complex members like c-jun were reflecting potential molecular events of liver growth after embolization. Immunofluorescence data confirmed a predominant upregulation of ß-catenin and c-jun (p<0.1) supported by Ki-67 (p<0.05) in the non-embolized liver. In silico analysis of transcriptomic dysplasia and hepatocellular carcinoma data showed divergent signatures compared to embolization. CONCLUSIONS: Our findings indicate a sustained regeneration after portal vein embolization reflected in hyperplasia and angiogenesis in the human liver and provide novel molecular mechanisms of interlobe crosstalk.

Hepatic Fibrosis in a Long-term Murine Model of Sepsis.

Chronic sequelae of sepsis represent a major, yet underappreciated clinical problem, contributing to long-term mortality and quality-of-life impairment. In chronic liver disease, inflammation perpetuates fibrogenesis, but development of fibrosis in the post-acute phase of systemic inflammation has not been studied. Therefore, a mouse model of post-acute sequelae of sepsis was established based on polymicrobial peritonitis under antibiotic protection. Survival decreased to approximately 40% within 7 days and remained constant until day 28 (post-acute phase). In survivors, clinical recovery was observed within 1 week, whereas white blood cell and platelet count, as well as markers of liver injury, remained elevated until day 28. Macroscopically, inflammation and abscess formation were detected in the peritoneal space and on/in the liver. Microscopically, acute-chronic inflammation with ductular proliferation, focal granuloma formation in the parenchyma, and substantial hepatic fibrosis were observed. Increased numbers of potentially pathogenetic macrophages and α-smooth muscle actin-positive cells, presumably activated hepatic stellate cells, were detected in the vicinity of fibrotic areas. Fibrosis was associated with the presence of elastin and an augmented production/deposition of collagen types I and III. Microarray analyses revealed early activation of canonical and noncanonical pathways of hepatic stellate cell transdifferentiation. Thus, chronic sequelae of experimental sepsis were characterized by abscess formation, persistent inflammation, and substantial liver injury and fibrosis, the latter associated with increased numbers of macrophages/α-smooth muscle actin-positive cells and deposition of collagen types I and III. This suggests persistent activation of stellate cells, with consecutive fibrosis-a hallmark of chronic liver disease-as a result of acute life-threatening infection.

MiR-21 is induced in endothelial cells by shear stress and modulates apoptosis and eNOS activity.

Mechanical forces associated with blood flow play an important role in regulating vascular signaling and gene expression in endothelial cells (ECs). MicroRNAs (miRNAs) are a class of noncoding RNAs that posttranscriptionally regulate the expression of genes involved in diverse cell functions, including differentiation, growth, proliferation, and apoptosis. miRNAs are known to have an important role in modulating EC biology, but their expression and functions in cells subjected to shear stress conditions are unknown. We sought to determine the miRNA expression profile in human ECs subjected to unidirectional shear stress and define the role of miR-21 in shear stress-induced changes in EC function. TLDA array and qRT-PCR analysis performed on HUVECs exposed to prolonged unidirectional shear stress (USS, 24h, 15 dynes/cm(2)) identified 13 miRNAs whose expression was significantly upregulated (p<0.05). The miRNA with the greatest change was miR-21; it was increased 5.2-fold (p=0.002) in USS-treated versus control cells. Western analysis demonstrated that PTEN, a known target of miR-21, was downregulated in HUVECs exposed to USS or transfected with pre-miR-21. Importantly, HUVECs overexpressing miR-21 had decreased apoptosis and increased eNOS phosphorylation and nitric oxide (NO(*)) production. These data demonstrate that shear stress forces regulate the expression of miRNAs in ECs, and that miR-21 influences endothelial biology by decreasing apoptosis and activating the NO(*) pathway. These studies advance our understanding of the mechanisms by which shear stress forces modulate vascular homeostasis.