Nanoparticles coated by chloramphenicol in hydrogels as a useful tool to increase the antibiotic release and antibacterial activity in dermal drug delivery

BACKGROUND

Nanocarriers for antibacterial drugs became hopeful tools against the increasing resistance of bacteria to antibiotics. This work focuses on a comprehensive study of the applicability and therapeutic suitability of dermal carbopol-based hydrogels containing chloramphenicol carried by various nanoparticles (AuNPs and SiNPs).

METHODS

The different forms of carbopol-based drugs for dermal use were obtained. Five different concentrations of chloramphenicol and two types of nanoparticles (silica and gold) in carbopol-based ointments were tested. The influence of different carbopol formulations with nanocarriers on the rheological properties as well as the release profile of active substances and bacteriostatic activity on five reference strains were determined.

RESULTS

The properties of the obtained hydrogels were compared to a commercial formulation, and finally it was possible to obtain a formulation that allowed improved antimicrobial activity over a commercially available detreomycin ointment while reducing the concentration of the antibiotic.

CONCLUSION

The work indicates that it is possible to reduce the concentration of chloramphenicol by four times while maintaining its bacteriostatic activity, which can improve the patient's safety profile while increasing the effectiveness of the therapy.

Structure of the lipopolysaccharide O-antigen of endophytic Pseudomonas sp. strain L1

The O-specific polysaccharide (OPS) was isolated from the lipopolysaccharide of Pseudomonas sp. Strain L1, the endophytic bacteria of Lolium perenne (ryegrass) plants growing in soil in an industrial area in the Silesia region (Zabrze, Southern Poland). The high-molecular-weight O-PS fraction liberated from Pseudomonas sp. L1 lipopolysaccharide by mild acid hydrolysis was studied using chemical methods, MALDI-TOF mass spectrometry, and 1D and 2D NMR spectroscopy techniques. It was found that the O-specific polysaccharide was built of tetrasaccharide repeating units composed of d-FucpN, d-Fucp4N, and two d-QuipN residues. The following structure of the O-PS of Pseudomonas sp. Strain L1 was established: [Formula: see text].

Structure of the lipopolysaccharide O-antigen of Serratia spp. strains 10.1WK and 1XS plant endophytes isolated from O. biennis and L. corniculatus

O-specific polysaccharides (O-PSs) isolated from lipopolysaccharides of Serratia spp., strains 10.1WK and 1XS, which are endophytic bacteria of Oenothera biennis (common evening-primrose) and Lotus corniculatus (bird's-foot trefoil), plants growing on a petroleum hydrocarbon polluted site in the Silesia region, were investigated. The high-molecular-weight O-PS fractions liberated from lipopolysaccharides by mild acid hydrolysis were studied using chemical methods, MALDI-TOF mass spectrometry, and a set of 1D and 2D NMR spectroscopy techniques. It was found that both O-specific polysaccharides were built of an identical trisaccharide repeating unit composed of d-Rhap and d-Manp residues. The following structure of the O-PSs of Serratia spp. strains 10.1WK and 1XS was established: →4)-α-d-Rhap-(1 → 3)-β-d-Manp-(1 → 4)-β-d-Rhap-(1→.

Characterization of biomaterials with reference to biocompatibility dedicated for patient-specific finger implants

PURPOSE

The research was focused on determining basic mechanical properties, surface, and phase structure taking into consideration basic cytotoxicity analysis towards human cells.

METHODS

Biological tests were performed on human C-12302 fibroblasts cells using 3D-printed Ti6Al4V alloy (Ti64), produced by laser-based powder bed fusion (LB-PBF) and Alumina Toughened Zirconia 20 (ATZ20), produced by lithography-based ceramic manufacturing (LCM). Surface modifications included electropolishing and hydroxyapatite or hydroxyapatite/zinc coating. Structure analysis was carried out using a variety of techniques such as X-Ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM), followed by mechanical properties evaluation using nanoindentation testing.

RESULTS

Samples subjected to surface modifications showed diversity among surface and phase structure and mechanical properties. However, the cytotoxicity towards tested cells was not significantly higher than the control. Though, a trend was noted among the materials analysed, indicating that HAp/Zn coating on Ti64 and ATZ20 resulted in the best biological performance increasing cell survivability by more than 10%.

CONCLUSIONS

Hydroxyapatite coating on Ti64 and ATZ20 resulted in the best biological properties. Tested materials are suitable for in vivo toxicity testin.

Effects of chronic exposure to cadmium and copper on the proteome profile of hemolymph in false widow spider Steatoda grossa (Theridiidae)

The aim of this study was to evaluate the quantitative and qualitative changes in the proteome of the hemolymph of female Steatoda grossa spiders (Theridiidae) that were chronically exposed to cadmium and copper in food and were additionally immunostimulated (phorbol 12-myristate 13-acetate (PMA); bacterial suspensions: Staphylococcus aureus (G+), Pseudomonas fluorescens (G-). It was found that the expression of nearly 90 proteins was altered in cadmium-intoxicated spiders and more than 60 in copper-exposed individuals. Regardless of the type of metal used, these proteins were mainly overexpressed in the hemolymph of the exposed spiders. On the other hand, immunostimulation did not significantly change the number of proteins with altered expression in metal-intoxicated individuals. Hemocyanin (Hc) was found to be the most abundant of the proteins identified with altered expression. In copper-intoxicated spiders, immunostimulation increased the expression of A-, E-, F-, and G-chain-containing proteins, while in the case of cadmium-intoxicates spiders, it decreased the expression of E- and A-chain-containing Hc and increased the expression of G-chain-containing Hc. Regardless of the type of metal and immunostimulant used, there was an increase in the expression of actin. In addition, cadmium increased the expression of cullin, vimentin, and ceruloplasmin. The changes observed in the expression of hemolymph proteins indicate their protective function in S. grossa (Theridiidae) spiders under conditions of metal exposure.

Hemocompatibile Thin Films Assessed under Blood Flow Shear Forces

The aim of this study was to minimize the risk of life-threatening thromboembolism in the ventricle through the use of a new biomimetic heart valve based on metal-polymer composites. Finite volume element simulations of blood adhesion to the material were carried out, encompassing radial flow and the cone and plane test together with determination of the effect of boundary conditions. Both tilt-disc and bicuspid valves do not have optimized blood flow due to their design based on rigid valve materials (leaflet made of pyrolytic carbon). The main objective was the development of materials with specific properties dedicated to contact with blood. Materials were evaluated by dynamic tests using blood, concentrates, and whole human blood. Hemostability tests under hydrodynamic conditions were related to the mechanical properties of thin-film materials obtained from tribological tests. The quality of the coatings was high enough to avoid damage to the coating even as they were exposed up to maximum loading. Analysis towards blood concentrates of the hydrogenated carbon sample and the nitrogen-doped hydrogenated carbon sample revealed that the interaction of the coating with erythrocytes was the strongest. Hemocompatibility evaluation under hydrodynamic conditions confirmed very good properties of the developed coatings.

Outer Membrane Vesicles as Mediators of Plant-Bacterial Interactions

Plants have co-evolved with diverse microorganisms that have developed different mechanisms of direct and indirect interactions with their host. Recently, greater attention has been paid to a direct “message” delivery pathway from bacteria to plants, mediated by the outer membrane vesicles (OMVs). OMVs produced by Gram-negative bacteria play significant roles in multiple interactions with other bacteria within the same community, the environment, and colonized hosts. The combined forces of innovative technologies and experience in the area of plant–bacterial interactions have put pressure on a detailed examination of the OMVs composition, the routes of their delivery to plant cells, and their significance in pathogenesis, protection, and plant growth promotion. This review synthesizes the available knowledge on OMVs in the context of possible mechanisms of interactions between OMVs, bacteria, and plant cells. OMVs are considered to be potential stimulators of the plant immune system, holding potential for application in plant bioprotection.

The effect of selected immunostimulants on hemocytes of the false black widow Steatoda grossa (Theridiidae) spiders under chronic exposition to cadmium

The aim of this study was to analyze whether, and to what extent, long-term exposure to cadmium, administered in sublethal concentrations by the oral route, caused changes in the immune potential of hemocytes in adult female Steatoda grossa spiders. We used artificial and natural immunostimulants, namely phorbol 12-myristate 13-acetate (PMA) and bacterial cell suspension based on Gram-positive (G+, Staphylococcus aureus) and Gram-negative (G-, Pseudomonas fluorescens) bacteria, to compare the status of hemocytes in nonstimulated individuals and those subjected to immunostimulation. After cadmium exposure, the percentage of small nongranular hemocytes in response to G+ cell suspension and PMA mitogen was decreased. Furthermore, in the cadmium-intoxicated spiders the percentage of plasmatocytes after immunostimulation remained lower compared to the complementary control group. Exposure to cadmium also induced several degenerative changes, including typical apoptotic and necrotic changes, in the analyzed types of cells. Immunostimulation by PMA mitogen and G+ bacterial suspension resulted in an increase in the number of cisterns in the rough endoplasmic reticulum of granulocytes, in both the control group and cadmium-treated individuals. These changes were accompanied with a low level of metallothioneins in hemolymph. Chronic cadmium exposure may significantly weaken the immune defense system of spiders during infections.

Patient specific implants for jawbone reconstruction after tumor resection

In case of benign and malignant tumours affecting the maxillofacial region, the resection of jawbone reflects the standard therapy in more than 5.000 cases per year within the European Union. The resulting large bone defects lead to scarred, mangled facial appearance, loss of mastication and probably speech, requiring aesthetic and functional surgery as a basis for physical and physiological rehabilitation. Although autologous vascularized bone autografts reflect the current golden standard, the portion of bone available for the procedure is limited and subsequent high-dose anti-cancer chemo-/radiotherapy can lead to local tissue necrosis. Autologous vascularized bone from fibular or iliac-crest autografts is current golden standard in jawbone resection post-treatment, however, the portion of transplantable bone is limited and subsequent high-dose anti-cancer chemo-/radiotherapy often results in tissue necrosis Our research focuses on alternative treatment techniques: tissue reconstruction via novel patient-specifically manufactured maxillofacial implant that stimulates bone tissue growth. The planned neoformation of vascularized bone in such implants within the patient's own body as "bioreactor" is the safest approach in tissue engineering. The works described herein included the design of the metallic substrate of the implant with the use of computed tomography basing on real patients scans and then 3D-printing the substrates from the Ti6Al7Nb powder. The metal core was then evaluated in terms of structural characteristic, cytotoxicity and gene expression through the in vitro tests. Further experiments were focused on fabrication of the biocompatible coating for outer surface of the bone implant that would enhance the healing process and accelerate the tissue growth. Functional polymeric granulate dedicated for osteoconductive, osteoinductive and osteogenesis properties were elaborated. Another approach including the coating for the implant surface with two-phase biocompatible layer including polymeric microspheres and hydrogel carrier, which would provide long-time release of bone and cartilage growth factors around the implant were also done. The polymeric granulate containing βTCP improved bone cells growth, but it some modification has to be done in order to improve structural pores to ensure for better osteoconductivity. The biocompatible coating including PVP hydrogel and polymeric microspheres is still in the development process.

The Role of Complement Activating Collectins and Associated Serine Proteases in Patients With Hematological Malignancies, Receiving High-Dose Chemotherapy, and Autologous Hematopoietic Stem Cell Transplantations (Auto-HSCT)

We conducted a prospective study of 312 patients (194 with multiple myeloma, 118 with lymphomas) receiving high-dose conditioning chemotherapy and autologous hematopoietic stem cell transplantation (auto-HSCT). Polymorphisms of MBL2 and MASP2 genes were investigated and serial measurements of serum concentrations of mannose-binding lectin (MBL), CL-LK collectin and MASP-2 as well as activities of MBL-MASP-1 and MBL-MASP-2 complex were made. Serum samples were taken before conditioning chemotherapy, before HSCT and once weekly after (totally 4-5 samples); in minority of subjects also 1 and/or 3 months post transplantation. The results were compared with data from 267 healthy controls and analyzed in relation to clinical data to explore possible associations with cancer and with chemotherapy-induced medical complications. We found a higher frequency of MBL deficiency-associated genotypes (LXA/O or O/O) among multiple myeloma patients compared with controls. It was however not associated with hospital infections or post-HSCT recovery of leukocytes, but seemed to be associated with the most severe infections during follow-up. Paradoxically, high MBL serum levels were a risk factor for prolonged fever and some infections. The first possible association of MBL2 gene 3′-untranslated region polymorphism with cancer (lymphoma) in Caucasians was noted. Heterozygosity for MASP2 gene +359 A>G mutation was relatively frequent in lymphoma patients who experienced bacteremia during hospital stay. The median concentration of CL-LK was higher in myeloma patients compared with healthy subjects. Chemotherapy induced marked increases in serum MBL and MASP-2 concentrations, prolonged for several weeks and relatively slighter decline in CL-LK level within 1 week. Conflicting findings on the influence of MBL on infections following chemotherapy of myeloma and lymphoma have been reported. Here we found no evidence for an association between MBL deficiency and infection during the short period of neutropenia following conditioning treatment before HSCT. However, we noted a possible protective effect of MBL during follow-up, and suspected that to be fully effective when able to act in combination with phagocytic cells after their recovery.

Lectin pathway factors in patients suffering from juvenile idiopathic arthritis

Both complement activation and certain infections (including those with Yersinia sp.) may contribute to the pathogenesis of juvenile idiopathic arthritis (JIA). We investigated factors specific for the lectin pathway of complement: mannose-binding lectin (MBL), ficolins and MBL-associated serine protease-2 (MASP-2), in 144 patients and 98 controls. One hundred and six patients had oligoarticular disease and 38 had polyarticular disease. In 51 patients (out of 133 tested), Yersinia-reactive antibodies were found (JIA Ye+ group). MBL deficiency was significantly more frequent in the JIA Ye+ group than in patients without Yersinia-reactive antibodies or in controls. Median serum ficolin-2 level was significantly lower (and proportion of values deemed ficolin-2 insufficient greater) in JIA patients irrespective of their Yersinia antibody status. The minority (C) allele at -64 of the FCN2 gene was less frequent among JIA patients than among control subjects. No differences were found in the frequency of FCN3 gene +1637delC or MASP2 +359 A>G mutations nor for median values of serum ficolin-1, ficolin-3 or MASP-2. However, high levels of serum ficolin-3 were under-represented in patients, in contrast to MBL. MBL, ficolin-1, ficolin-2, ficolin-3 and MASP-2 were also readily detectable in synovial fluid samples but at a considerably lower level than in serum. Our findings suggest a possible role for the lectin pathway in the pathogenesis of JIA, perhaps secondary to a role in host defence, and indicate that investigations on the specificity of lectin pathway recognition molecules towards specific infectious agents in JIA might be fruitful.

Human Microbiome: When a Friend Becomes an Enemy

The microorganisms that inhabit humans are very diverse on different body sites and tracts. Each specific niche contains a unique composition of the microorganisms that are important for a balanced human physiology. Microbial cells outnumber human cells by tenfold and they function as an invisible organ that is called the microbiome. Excessive use of antibiotics and unhealthy diets pose a serious danger to the composition of the microbiome. An imbalance in the microbial community may cause pathological conditions of the digestive system such as obesity, cancer and inflammatory bowel disease; of the skin such as atopic dermatitis, psoriasis and acne and of the cardiovascular system such as atherosclerosis. An unbalanced microbiome has also been associated with neurodevelopmental disorders such as autism and multiple sclerosis. While the microbiome has a strong impact on the development of the host immune system, it is suspected that it can also be the cause of certain autoimmune diseases, including diabetes or rheumatoid arthritis. Despite the enormous progress in the field, the interactions between the human body and its microbiome still remain largely unknown. A better characterization of the interactions may allow for a deeper understanding of human disease states and help to elucidate a possible association between the composition of the microbiome and certain pathologies. This review focuses on general findings that are related to the area and provides no detailed information about the case of study. The aim is to give some initial insight on the studies of the microbiome and its connection with human health.

Interaction of human mannose-binding lectin (MBL) with Yersinia enterocolitica lipopolysaccharide

The lipopolysaccharide (LPS) is involved in the interaction between Gram-negative pathogenic bacteria and host. Mannose-binding lectin (MBL), complement-activating soluble pattern-recognition receptor targets microbial glycoconjugates, including LPS. We studied its interactions with a set of Yersinia enterocolitica O:3 LPS mutants. The wild-type strain LPS consists of lipid A (LA) substituted with an inner core oligosaccharide (IC) which in turn is substituted either with the O-specific polysaccharide (OPS) or the outer core hexasaccharide (OC), and sometimes also with the enterobacterial common antigen (ECA). The LPS mutants produced truncated LPS, missing OPS, OC or both, or, in addition, different IC constituents or ECA. MBL bound to LA-IC, LA-IC-OPS and LA-IC-ECA but not LA-IC-OC structures. Moreover, LA-IC substitution with both OPS and ECA prevented the lectin binding. Sequential truncation of the IC heptoses demonstrated that the MBL targets the IC heptose region. Furthermore, microbial growth temperature influenced MBL binding; binding was stronger to bacteria grown at room temperature (22°C) than to bacteria grown at 37°C. In conclusion, our results demonstrate that MBL can interact with Y. enterocolitica LPS, however, the in vivo significance of that interaction remains to be elucidated.