Chitosan derivatives substituted with benzophenone groups that can be cross-linked by ultraviolet light were synthesized as coatings for PEEK substrates used in the construction of lumbar cages. The IC90 values of the benzophenone-modified chitosan polymers in solution before crosslinking were in the same range as those reported for native chitosan. The resulting hydrogel surface after crosslinking exhibited excellent antimicrobial properties and was highly effective (up to 5 log-fold) against clinically relevant strains of methicillin-resistant S. aureus and E. coli. As a result, the coated surface also signifi-cantly reduced biofilm formation. The coatings show good biocompatibility with numerous cell lines as well as low levels of cytotoxicity (ISO 10993-5) and pyrogenicity (ISO 10993-11). The coatings also exhibited strong antioxidant properties toward formed hydroxyl radicals in an in-vitro Fenton reaction. Overall, substitution of chitosan with benzophenone residues is an interesting and important approach to the functionalization of materials used for medical implants that are prone to microbial contamination and mechanical failure. Biocompatible antimicrobial coatings might also be employed in photopatterning methods used in the design of medical devices.(c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Einleitung Klassische Parameter (pH, BE, APGAR- und Thompson-Score) sowie klinische Zeichen sind im Allgemeinen zu ungenau, um Neugeborene (NG) frühzeitig zu erkennen, die von einer neuroprotektiven Therapie profitieren könnten. Die AAMBI Studie dient der Identifikation von Metaboliten als Biomarker für eine hypoxisch-ischämische Enzephalopathie (HIE), um diese diagnostische Lücke zu schließen.
Rebuilding, stabilizing and maintaining the dermal lipid barrier is an encouraging disease management concept (relief and care) in the treatment and prevention of atopic dermatitis. Prevention and topical treatment, however, lack a simple, safe, effective and modular approach. For decades, the mainstay of topical therapy of atopic dermatitis has been corticosteroids, with innovations being rare. Our case report demonstrates the struggle of a patient with little relief of itchy dermal lesions and the recurrence of skin lesions following current therapeutic guidelines which proved to be ineffective. Therefore we decided to try an advanced C16-ceramide pathomechanism derived topical therapeutic measure since it offers hope of re-establishing skin and alleviating suffering. Amitriptyline in combination with linoleic acid offers a chance to release from dry and itchy skin, mild to moderate atopic dermatitis lesions without known serious adverse effects of topical corticosteroids, while preventing recurrence.
Concentration and distribution of individual endogenous ceramide species is crucial for apoptosis induction in response to various stimuli. Exogenous ceramide analogs induce apoptosis and can in turn modify the composition/concentrations of endogenous ceramide species and associated signaling. In this study, we show here that the elevation of endogenous C16-ceramide levels is a common feature of several known apoptosis-inducing triggers like mmLDL, TNF-alpha, H2O2 and exogenous C6-ceramide. Vice versa apoptosis requires elevation of endogenous C16-ceramide levels in cells. Enantiomers of a synthetic ceramide analog HPL-1RS36N have been developed as probes and vary in their capacity to inducing apoptosis in macrophages and HT-29 cells. Apoptosis induction by the two synthetic ceramide analogs HPL-39N and HPL-1R36N correlates with generation of cellular C16-ceramide concentration. In contrast to the S-enantiomer HPL-1S36N, the R-enantiomer HPL-1R36N shows significant effects on the expression of distinct genes known to be involved in cell cycle, cell growth and cell death (CXCL10, CCL5 and TNF-alpha), similarly on apoptosis induction. Enantioselective effects on transcription induced by metabolically stable synthetic probes provide clues on molecular mechanisms of ceramide-induced signaling, as well as leads for future anti-cancer agents.
Background The interactions of oxidized low-density lipoprotein (LDL) and macrophages are hallmarks in the development of atherosclerosis. The biological activities of the modified particle in these cells are due to the content of lipid oxidation products and apolipoprotein modification by oxidized phospholipids. Results It was the aim of this study to determine the role of short-chain oxidized phospholipids as components of modified LDL in cultured macrophages. For this purpose we investigated the effects of the following oxidized phospholipids on cell viability and apoptosis: 1-palmitoyl-2-glutaroyl- sn -glycero-3-phosphocholine (PGPC), 1-palmitoyl-2-(5-oxovaleroyl)- sn -glycero-3-phosphocholine (POVPC) and oxidized alkylacyl phospholipids including 1-O-hexadecyl-2-glutaroyl- sn -glycero-3-phosphocholine (E-PGPC) and 1-O-hexadecyl-2-(5-oxovaleroyl)- sn -glycero-3-phosphocholine (E-POVPC). We found that these compounds induced apoptosis in RAW264.7 and bone marrow-derived macrophages. The sn- 2 carboxyacyl lipid PGPC was more toxic than POVPC which carries a reactive aldehyde function in position sn- 2 of glycerol. The alkylacyl phospholipids (E-PGPC and E-POVPC) and the respective diacyl analogs show similar activities. Apoptosis induced by POVPC and its alkylether derivative could be causally linked to the fast activation of an acid sphingomyelinase, generating the apoptotic second messenger ceramide. In contrast, PGPC and its ether analog only negligibly affected this enzyme pointing to an entirely different mechanism of lipid toxicity. The higher toxicity of PGPC is underscored by more efficient membrane blebbing from apoptotic cells. In addition, the protein pattern of PGPC-induced microparticles is different from the vesicles generated by POPVC. Conclusions In summary, our data reveal that oxidized phospholipids induce apoptosis in cultured macrophages. The mechanism of lipid toxicity, however, largely depends on the structural features of the oxidized sn- 2 chain.
Community‐acquired pneumonia presents a spectrum of clinical phenotypes, from lobar pneumonia to septic shock, while mechanisms underlying progression are incompletely understood. In a transcriptomic and metabolomic study across tissues, we examined serotype‐specific regulation of signaling and metabolic pathways in C57BL/6 mice intratracheally instilled with either serotype 19F Streptococcus pneumoniae (S19; causing lobar pneumonia), or serotype 2 S. pneumoniae (S2; causing septic pneumococcal disease,) or vehicle (Todd‐Hewitt broth). Samples of lung, liver, and blood were collected at 6 and 24 h postinfection and subjected to microarray analysis and mass spectrometry. Results comprise a preferential induction of cholesterol biosynthesis in lobar pneumonia at low‐infection doses (105 colony forming units/mouse) leading to increased plasma cholesterol (vehicle: 1.8 ±0.12 mM, S2: 2.3±0.10 mM, S19: 2.9±0.15 mM; P>0.05, comparing S19 to vehicle and S2). This induction was pneumolysin dependent, as a pneumolysin‐deficient strain of serotype 19F failed to induce cholesterol biosynthesis (S19ΔPLY: 1.9±0.03 mM). Preincubation of pneumolysin with purified cholesterol or plasma from hypercholesterolemic mice prior to intratracheal instillation protected against lung barrier dysfunction and alveolar macrophage necrosis. Cholesterol may attenuate disease severity by neutralizing pneumolysin in the alveolar compartment and thus prevent septic disease progression.—Weber, M., Lambeck, S., Ding, N., Henken, S., Kohl, M., Deigner, H. P., Enot, D. P., Igwe, E. I., Frappart, L., Kiehntopf, M., Claus, R. A., Kamradt, T., Weih, D., Vodovotz, Y., Briles, D. E., Ogunniyi, A. D., Paton, J. C., Maus, U. A., Bauer, M. Hepatic induction of cholesterol biosynthesis reflects a remote adaptive response to pneumococcal pneumonia. FASEB J. 26, 2424‐2436 (2012). www.fasebj.org
An aqueous extract of propolis and the phenolic component of propolis, propol, were assayed for antioxidative and antiapoptotic properties. Both additions inhibited Cu(2+)-initiated low density lipoprotein (LDL) oxidation as characterized by a reduction of the lag time, reduced the increase of relative electrophoretic mobility during oxidation and markedly diminished apoptosis of human macrophages exposed to minimally modified (mmLDL). Moreover, aqueous propolis extract and propol blocked the mmLDL-induced decrease of glutathione (GSH) and the activation of the transcription factor NF-kappa B in these cells. The potent phenolic antioxidant propol thus expands the capability of cells to neutralize oxidative stress and to prevent apoptosis and is therefore suggested to significantly contribute to the antiinflammatory and antioxidative effects of propolis.
Background and aims: A novel component in the Neobrain consortium was the large scale quantification of metabolites and their implication/use for translational research. Here we report on the Methods: Study comprises animal models of hypoxia-ischemia, excitotoxic brain injury and intrauterine LPS exposure in fetal sheep and a human cohort of 41 preterm infants (28-32 weeks of gestation). Metabolite panel covering 230 compounds (acylcarnitines, lipids, prostanoids, amino acids and derivatives, oxidised products of cholesterol, small organic acids,sugars) was applied in plasma. In the sheep model and infants, extend of brain damage has been assessed by MRI, aEEG and histopathology in animals. Results: Insults causing brain injury induced significant changes in the plasma metabolome in all animal models. In the sheep model we detected a significant correlation of metabolites with outcome at several time points. In the preterm infants ADMA/SDMA, specific acyl carnitines, lysoPCs and amino acids were significantly increased in infants with abnormal MRI at term, overlapping with metabolites detected in the animal models. Conclusions: Hypothesized at the start at the project, metabolic changes associated with perinatal brain injury is demonstrated in several animal models and translated in humans. Metabolite profiling can effectively be applied to pediatric research to complete our fragmented knowledge. It enables identification of patterns of dysregulation (biomarker discovery) together with the elucidation of their underlying mechanism (biological plausibility).
The gap of the post-genomic era is increasingly being filled by the metabolomics approach, comprising a technology for analyzing small molecule endogenous metabolites (<1500 Dalton) in complex biological samples. This new analytical science has progressed within the last years particularly with regard to improvements in mass spectrometry based detection, now allowing highly robust, reproducible, selective and sensitive qualitative or quantitative analysis of endogenous metabolites. The precise and accurate quantitation of these metabolites via targeted metabolomics, now critically contributes to the quantitative analysis of endogenous compounds in biomarker discovery and validation thus to future personalized therapy. The analytical methods of choice in (MS-based) targeted metabolomics primarily are HPLC-API-MS/MS, FIA-APIMS/MS and GC-MS. In the parent paper, we provide an introduction and brief survey on the technological basis of targeted metabolomics in biomarker research, discuss various relevant analytical aspects in mass spectrometry including comparison to non-targeted approaches, effects of sample preparation, impact of sample stability, carryover- and matrix effects, need for standardization and for proficiency tests, standardization of analytical methods as well as the requirement for method validation.
The 'systemic inflammatory response syndrome (SIRS)' reflects a non-specific inflammatory reaction to various insults. In sepsis, defined as SIRS triggered by infection, a complex and overwhelming network of mediators contributes to the clinical syndrome. The host response in sepsis is characterized by unspecific physiologic criteria, which are unable to identify patients adequately who might benefit from either conventional anti-infective therapies or from novel therapies targeting specific mediators of sepsis. The early diagnosis of sepsis, the identification of the origin, adequate therapeutical management and the monitoring of the disease may help to overcome sepsis-associated mortality, which is unacceptably high and the third leading cause of death in Western Countries. Molecular techniques for identification of pathogens, their associated molecular patterns (PAMPs) and the ensuing host response may help to stratify patients with the urgent need for antibiotic therapy and those where it is safe to withhold or to de-escalate therapy. Beyond analysis of danger associated molecular patterns (DAMPs) at a single molecular level, the advent of genome-wide screening allows for an assessment of a wide variety of effectors and mediators in response to PAMPs. Also their purposeful targeting in animal models of sepsis revolutionized our understanding of pathophysiology in the critically ill. Molecular tools are about to challenge "state-of-the-art" diagnostic tests such as blood culture as they not only increase sensitivity but also dramatically reduce time requirements to identify pathogens and their resistance patterns. Mounting evidence suggests that our pathophysiological understanding might in the near future help to identify "patients at risk", i.e. those with a high likelihood to develop organ dysfunction and/or to guide therapeutic interventions in particular regarding resource-consuming and expensive therapies ("theragnostics"). The clinical utility for most of the discussed markers for monitoring systemic inflammation and sepsis has still to be evaluated in prospective trails. In conclusion, there is an unmet medical need for identification and validation of reliable biomarkers of sepsis; the clinical information obtained from the use of novel biomarkers might contribute to transform sepsis from a physiologic syndrome to a group of distinct biochemical disorders, to improve diagnosis and therapeutic decision making for high-risk patients, to monitor the response to therapy and to ensure the enrollment of seriously characterized patients in clinical studies.
Ceramide, an intracellular lipid mediator, is generated by transient hydrolysis of sphingomyelin in response to agonists inducing inflammation and apoptosis, ionizing radiation, chemotherapeutics or ischaemia/reperfusion. An elevated intracellular ceramide production is predominantly induced by an elevated hydrolytic activity of sphingomyelinases or by the activity of enzymes controlling de novo synthesis, such as ceramide synthase. Ceramide is implicated in various cellular responses, acting as an autonomous intracellular effector in cell cycle regulation, differentiation, senescence, and apoptosis. Furthermore, by changing membrane properties it contributes to the assembly and interactions of various signal transduction molecules. The lipid mediator is subsequently metabolised by ceramidase and sphingosine kinase, and other key players, which determine the dynamic balance between the intracellular levels of ceramide and its breakdown products (the ceramide/S1P rheostat). Together with sphingomyelinases, they are crucial for cell signalling, cellular survival or initiation of apoptosis. Sphingomyelinases are regarded as key enzymes in the regulated activation of the sphingomyelin cycle. Up to now, five isoforms of sphingomyelinases are known, differentiated by agonists, intracellular localization, pH optimum and essential co-factors. Herein, we focus on the biochemical background and the action of pharmacologically interesting compounds capable of interfering with sphingomyelinases and outline their potential implications for medicinal chemistry.
School of Chemical Sciences and Pharmacy; University of East Anglia; Norwich, United Kingdom (Deigner) University of Bayreuth; Bayreuth, Germany (Kohl) Dr. Deigner holds several patents relevant to sepsis identification. Dr. Kohl has not disclosed any potential conflicts of interest.