Biocompatibility of mannan nanogel : safe interaction with plasma proteins

BACKGROUND: Self-assembled mannan nanogels are designed to provide a therapeutic or vaccine delivery platform based on the bioactive properties of mannan to target mannose receptor expressed on the surface of antigen-presenting cells, combined with the performance of nanogels as carriers of biologically active agents. METHODS: Proteins in the corona around mannan nanogel formed in human plasma were identified by mass spectrometry after size exclusion chromatography or centrifugation followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Structural changes and time dependent binding of human apolipoprotein A-I (apoA-I) and human serum albumin (HSA) to mannan nanogel were studied using intrinsic tryptophan fluorescence and circular dichroism spectroscopy. The mannan nanogel effect on blood coagulation and fibrillation of Alzheimer's disease-associated amyloid β peptide and hemodialysis-associated amyloidosis β2 microglobulin was evaluated using thrombin generation assay or thioflavin T fluorescence assay, respectively. RESULTS: The protein corona around mannan nanogel is formed through a slow process, is quite specific comprising apolipoproteins B-100, A-I and E and HSA, evolves over time, and the equilibrium is reached after hours to days. Structural changes and time dependent binding of apoA-I and HSA to mannan nanogel are minor. The mannan nanogel does not affect blood coagulation and retards the fibril formation. CONCLUSIONS: Mannan nanogel has a high biosafety and biocompatibility, which is mandatory for nanomaterials to be used in biomedical applications. GENERAL SIGNIFICANCE: Our research provides a molecular approach to evaluate the safety aspects of nanomaterials, which is of general concern in society and science.The authors thank the financial support by International Iberian Nanotechnology Laboratory (INL), Fundacao para a Ciencia e a Tecnologia (FCT, Portugal), through PTDC, European Science Foundation (ESF) for the activity entitled 'Mapping the detailed composition of Surface-Absorbed Protein Layers on Biomaterials and Nanoparticles', the Crafoord Foundation, and Lund and Nano Vaccine Center, Denmark. The NIPAM coated gold particle is a kind gift from Colloidal Chemistry Group from Vigo University, Spain

Clinicopathologic Features of Primary Merkel Cell Carcinoma: A Detailed Descriptive Analysis of a Large Contemporary Cohort

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98776/1/dsu12194.pd

Validity and reliability of the Dutch translation of the VISA-P questionnaire for patellar tendinopathy

Background: The VISA-P questionnaire evaluates severity of symptoms, knee function and ability to play sports in athletes with patellar tendinopathy. This English-language self-administered brief patient outcome score was developed in Australia to monitor rehabilitation and to evaluate outcome of clinical studies. Aim of this study was to translate the questionnaire into Dutch and to study the reliability and validity of the Dutch version of the VISA-P. Methods: The questionnaire was translated into Dutch according to internationally recommended guidelines. Test-retest reliability was determined in 99 students with a time interval of 2.5 weeks. To determine discriminative validity of the Dutch VISA-P, 18 healthy students, 15 competitive volleyball players (at-risk population), 14 patients with patellar tendinopathy, 6 patients who had surgery for patellar tendinopathy, 17 patients with knee injuries other than patellar tendinopathy, and 9 patients with symptoms unrelated to their knees completed the Dutch VISA-P. Results: The Dutch VISA-P questionnaire showed satisfactory test-retest reliability (ICC = 0.74). The mean (+/- SD) VISA-P scores were 95 (+/- 9) for the healthy students, 89 (+/- 11) for the volleyball players, 58 (+/- 19) for patients with patellar tendinopathy, and 56 (+/- 21) for athletes who had surgery for patellar tendinopathy. Patients with other knee injuries or symptoms unrelated to the knee scored 62 (+/- 24) and 77 (+/- 24). Conclusion: The translated Dutch version of the VISA-P questionnaire is equivalent to its original version, has satisfactory test-retest reliability and is a valid score to evaluate symptoms, knee function and ability to play sports of Dutch athletes with patellar tendinopathy

Expression and Activity of a Novel Cathelicidin from Domestic Cats

Cathelicidins are small cationic antimicrobial peptides found in many species including primates, mammals, marsupials, birds and even more primitive vertebrates, such as the hagfish. Some animals encode multiple cathelicidins in their genome, whereas others have only one. This report identifies and characterizes feline cathelicidin (feCath) as the sole cathelicidin in domestic cats (Felis catus). Expression of feCath is predominantly found in the bone marrow, with lower levels of expression in the gastrointestinal tract and skin. By immunocytochemistry, feCath localizes to the cytoplasm of neutrophils in feline peripheral blood. Structurally, the mature feCath sequence is most similar to a subgroup of cathelicidins that form linear α-helices. feCath possesses antimicrobial activity against E. coli D31, Salmonella enterica serovar Typhimurium (IR715), Listeria monocytogenes and Staphylococcus pseudintermedius (clinical isolate) similar to that of the human ortholog, LL-37. In contrast, feCath lacks the DNA binding activity seen with LL-37. Given its similarity in sequence, structure, tissue expression, and antimicrobial activity, the cathelicidin encoded by cats, feCath, belongs to the subgroup of linear cathelicidins found not only in humans, but also non-human primates, dogs, mice, and rats

Epithelial antimicrobial peptides in host defense against infection

One component of host defense at mucosal surfaces seems to be epithelium-derived antimicrobial peptides. Antimicrobial peptides are classified on the basis of their structure and amino acid motifs. Peptides of the defensin, cathelicidin, and histatin classes are found in humans. In the airways, α-defensins and the cathelicidin LL-37/hCAP-18 originate from neutrophils. β-Defensins and LL-37/hCAP-18 are produced by the respiratory epithelium and the alveolar macrophage and secreted into the airway surface fluid. Beside their direct antimicrobial function, antimicrobial peptides have multiple roles as mediators of inflammation with effects on epithelial and inflammatory cells, influencing such diverse processes as proliferation, immune induction, wound healing, cytokine release, chemotaxis, protease-antiprotease balance, and redox homeostasis. Further, antimicrobial peptides qualify as prototypes of innovative drugs that might be used as antibiotics, anti-lipopolysaccharide drugs, or modifiers of inflammation

Medical-grade honey enriched with antimicrobial peptides has enhanced activity against antibiotic-resistant pathogens

Honey has potent activity against both antibiotic-sensitive and -resistant bacteria, and is an interesting agent for topical antimicrobial application to wounds. As honey is diluted by wound exudate, rapid bactericidal activity up to high dilution is a prerequisite for its successful application. We investigated the kinetics of the killing of antibiotic-resistant bacteria by RS honey, the source for the production of Revamil® medical-grade honey, and we aimed to enhance the rapid bactericidal activity of RS honey by enrichment with its endogenous compounds or the addition of antimicrobial peptides (AMPs). RS honey killed antibiotic-resistant isolates of Pseudomonas aeruginosa, Staphylococcus epidermidis, Enterococcus faecium, and Burkholderia cepacia within 2 h, but lacked such rapid activity against methicillin-resistant S. aureus (MRSA) and extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. It was not feasible to enhance the rapid activity of RS honey by enrichment with endogenous compounds, but RS honey enriched with 75 μM of the synthetic peptide Bactericidal Peptide 2 (BP2) showed rapid bactericidal activity against all species tested, including MRSA and ESBL E. coli, at up to 10–20-fold dilution. RS honey enriched with BP2 rapidly killed all bacteria tested and had a broader spectrum of bactericidal activity than either BP2 or honey alone

Impaired Release of Antimicrobial Peptides into Nasal Fluid of Hyper-IgE and CVID Patients

Patients with primary immunodeficiency (PID) often suffer from frequent respiratory tract infections. Despite standard treatment with IgG-substitution and antibiotics many patients do not improve significantly. Therefore, we hypothesized that additional immune deficits may be present among these patients.To investigate if PID patients exhibit impaired production of antimicrobial peptides (AMPs) in nasal fluid and a possible link between AMP-expression and Th17-cells.Nasal fluid, nasopharyngeal swabs and peripheral blood mononuclear cells (PBMCs) were collected from patients and healthy controls. AMP levels were measured in nasal fluid by Western blotting. Nasal swabs were cultured for bacteria. PBMCs were stimulated with antigen and the supernatants were assessed for IL-17A release by ELISA.In healthy controls and most patients, AMP levels in nasal fluid were increased in response to pathogenic bacteria. However, this increase was absent in patients with common variable immunodeficiency (CVID) and Hyper-IgE syndrome (HIES), despite the presence of pathogenic bacteria. Furthermore, stimulation of PBMCs revealed that both HIES and CVID patients exhibited an impaired production of IL-17A.CVID and HIES patients appear to have a dysregulated AMP response to pathogenic bacteria in the upper respiratory tract, which could be linked to an aberrant Th17 cell response

Human antimicrobial protein hCAP18/LL-37 promotes a metastatic phenotype in breast cancer

International audienc

Human antimicrobial peptide LL-37 is present in atherosclerotic plaques and induces death of vascular smooth muscle cells: a laboratory study

BACKGROUND: Death of smooth muscle cells in the atherosclerotic plaques makes the plaques more prone to rupture, which can initiate an acute ischemic event. The development of atherosclerosis includes the migration of immune cells e.g. monocytes/macrophages and T lymphocytes into the lesions. Immune cells can release antimicrobial peptides. One of these, human cathelicidin antimicrobial peptide hCAP-18, is cleaved by proteinase 3 generating a 4.5 kDa C-terminal fragment named LL-37, which has been shown to be cytotoxic. The aim of the study was to explore a potential role of LL-37 in the pathophysiology of atherosclerosis. METHODS: We investigated the presence of LL-37 in human atherosclerotic lesions obtained at autopsy using immunohistochemistry. The direct effects of LL-37 on cultured vascular smooth muscle cells and isolated neutrophil granulocytes were investigated with morphological, biochemical and flow cytometry analysis. RESULTS: The neointima of atherosclerotic plaques was found to contain LL-37-like immunoreactivity, mainly in macrophages. In cultured smooth muscle cells, LL-37 at 30 μg/ml caused cell shrinkage, membrane blebbing, nuclear condensation, DNA fragmentation and an increase in caspase-3 activity as studied by microscopy, ELISA and enzyme activity assay, respectively. Flow cytometry demonstrated that LL-37 in a subset of the cells caused a small but rapidly developing increase in membrane permeability to propidium iodide, followed by a gradual development of FITC-annexin V binding. Another cell population stained heavily with both propidium iodide and FITC-annexin V. Neutrophil granulocytes were resistant to these effects of LL-37. CONCLUSION: This study shows that LL-37 is present in atherosclerotic lesions and that it induces death of vascular smooth muscle cells. In a subset of cells, the changes indicate the development of apoptosis triggered by an initial mild perturbation of plasma membrane integrity. The findings suggest a role for LL-37 as a mediator of immune cell-induced death of vascular smooth muscle cells in atherosclerosis