Lipid Material Research Articles

A-119 Lipemia Interference

Abstract Background Lipemic specimens is a common problem in clinical laboratories. Analytical results may be perturbed by lipemia, leading to misdiagnosis and unnecessary treatments for patients. Serum index testing is an important preanalytical test for assessing the potential effect of endogenous HIL interferents (hemoglobin (H), bilirubin (I) or lipids (L)) on test results. Automated HIL systems are not standardized and differ in their response. HIL induced interference should be verified by all clinical laboratories. Intralipid, a commercial lipid emulsion with particle size ranges from 200 to 600 nm is often used to verify the L index. However, intralipid lacks particles that mimic large VLDL, as well as the lower and upper ranges for chylomicrons size. In contrast, patient samples contain a complex mixture of macromolecular lipid and protein structures. Therefore, lipemia induced by Intralipid is not identical to lipemia in patient serum samples. The purpose of this study is to increase awareness of lipid interference and demonstrate the relationship of a lipid L Index to intralipid and triglyceride interference. Methods A set of 16 panels were prepared from a commercially available Triglyceride rich Lipoprotein material. These panels spanned a lipid concentration from 0 to 3000 mg/dL. Panels were tested on the Alinity c and ARCHITECT c8000 TRIG2 assays (04U0615 and 04T1016 respectively) on 2 reagent lots in a single run to determine the Triglyceride concentration. Then these samples were assessed for an HIL L score using the Abbott HIL saline protocol. Results The relationship between the Triglyceride rich Lipoprotein and the L Index was linear with a high correlation (r= 0.999) for Alinity and ARCHITECT respectively. The L Index underestimated the Triglyceride Rich Lipoprotein concentration. The reason for the lower estimate of Triglyceride rich lipoprotein specimens on an L Index is likely due to the differences in size of the lipid particles between the two artificial lipid materials, Intralipid and Triglyceride rich lipoprotein. In addition, while the triglyceride assay provides a quantitative measurement of the lipemic concentration, the L Index is designed to provide an estimated result. Conclusions Intralipid is an acceptable material used to verify spectrophotometric HIL systems. The L Index provides an estimate of sample turbidity, not the concentration of Triglyceride. Vendor purchased human derived Triglyceride rich lipoprotein, which contains a heterological mixture of lipid particles, may be regarded as a more appropriate material for assessing lipid interference. Thus, while recovery of the L Index correlates well to the Intralipid concentration, it can have a poorer correlation with vendor purchased samples containing Triglyceride due to the different vesicle sizes in these materials. This study demonstrates the Triglyceride rich material used to assess lipid interference in Sigma Strong assays provides a difference in response between the Triglyceride concentration of this material determined on a Triglyceride assay vs the L Index. The choice of lipemic material to use, (eg. artificial, native), can influence the results. Thus, care should be taken in comparing results for these materials.

Profiling patent compounds in lipid nanoparticle formulations of siRNA

Lipid nanoparticles (LNPs) have emerged as a prominent delivery system for nucleic acid drugs, attracting significant attention especially through the successful development of several commercial products. As a key component in LNPs, cationic lipids along serve as key technical barrier to block competitors by building up complex patent thicket. However, there have been few studies as yet that have comprehensively analyzed the patented compounds in LNP formulations, despite a large number of technical reviews and original articles. In the context, this study focuses on analyzing the macroscopic landscapes and microscopic molecular characteristics of LNP patents, aiming to provide a valuable reference for researchers and developers in making informed technological and commercial decisions. By mining 2,994 patents, 265 formulas, 7,674 compounds and 28,789 fragments, this work sketched the empirical golden ratio of lipid materials in LNP formulation, disclosed the advanced technology in the formulation, characterized high-frequency fragments of heads, linkers and tails in both novel cationic lipids as well as targeting lipids, and established a virtual focus library of LNP materials.

Personalization of lipid-based oral dosage forms via filament-based 3D-printing

While filament-based 3D-printing (3DP) is the most utilized 3DP technology in the pharmaceutical field, it has not been demonstrated for processing of drug-loaded lipid-based formulations. This work exploits hexa-glycerol ester of palmitic acid (Pg6-C16-P) as an advanced lipid material, loaded with felodipine as a poorly soluble model drug, for fabricating novel oral solid dosage forms (OSDFs) via filament-based 3D-printing. After material melt-blending, the formulation was extruded using the liquid feeding approach to obtain a mechanically manageable, and hence 3D-printable, drug-loaded lipid filament. The fabrication of geometries with variable infill densities was demonstrated. The extent of infill density was found to significantly impact the optimal printing parameters required to achieve the desired shape. The solid-state analysis confirmed the amorphous state of felodipine after 3DP. The release rate of the drug was studied via in vitro dissolution test and showed to be tunable based on the tablet geometry. It was also possible to tailor the design of the dosage form to perform similarly to a commercial product. The formulation was evidenced as safe via in vitro toxicity studies with improved felodipine solubility. This study establishes filament-based 3DP as an alternative platform viable for fabricating advanced lipid-based OSDFs, and concurrently, promotes Pg6-C16-P as a promising and high performing 3DP lipid material for drug delivery.

Reformulating lipid nanoparticles for organ-targeted mRNA accumulation and translation

Fully targeted mRNA therapeutics necessitate simultaneous organ-specific accumulation and effective translation. Despite some progress, delivery systems are still unable to fully achieve this. Here, we reformulate lipid nanoparticles (LNPs) through adjustments in lipid material structures and compositions to systematically achieve the pulmonary and hepatic (respectively) targeted mRNA distribution and expression. A combinatorial library of degradable-core based ionizable cationic lipids is designed, following by optimisation of LNP compositions. Contrary to current LNP paradigms, our findings demonstrate that cholesterol and phospholipid are dispensable for LNP functionality. Specifically, cholesterol-removal addresses the persistent challenge of preventing nanoparticle accumulation in hepatic tissues. By modulating and simplifying intrinsic LNP components, concurrent mRNA accumulation and translation is achieved in the lung and liver, respectively. This targeting strategy is applicable to existing LNP systems with potential to expand the progress of precise mRNA therapy for diverse diseases.

Technological Properties of Tritordeum Starch

Tritordeum is a new promising cereal derived from wild barley and cultivated durum wheat; such a combination allowed for the transfer of some useful barley traits to the resulting hybrid. In the future, the importance of this cereal can increase, becoming a raw material for the production of various products, including starch. So far, tritordeum starch has attracted little interest from researchers, and therefore, an attempt was undertaken to investigate its properties. Its morphological features, chemical composition, thermal and pasting properties, particle size, and retrogradation kinetics were investigated. These properties were compared to other cereal starches. Tritordeum starch granules resembled wheat starch in shape, and they were characterized by a relatively small size and the highest lipid and non-starch material content among the investigated starches. Tritordeum starch’s pasting profile showed a unique character, resulting in high pasting temperature and low, but stable, hot paste viscosity. Also, its rate of retrogradation was the lowest, probably due to the high lipid content, and the retrogradation extent was restricted.

Unlocking Delivery Strategies for mRNA Therapeutics.

mRNA emerged as an attractive therapy modality with the development of mRNA structure engineering techniques and delivery platforms. mRNA therapeutics, applied for vaccine therapy, protein replacement therapy, and chimeric antigen receptor (CAR) T cell-based therapy, has shown huge potential in treating a wide range of diseases, such as cancer and rare genetic diseases, with successful and exciting preclinical and clinical progress. In mRNA therapeutics, a potent delivery system is key to the success of its application for disease treatment. Herein, different types of mRNA delivery strategies, including nanoparticles produced from lipid or polymer materials, virus-based platforms, and exosome-based platforms, are mainly focused.

Structuring PUFA-rich oils with monoglycerides: Physicochemical and nutritional properties of fat substitutes with high-lipid quality

Driven by the demand for semisolid lipid materials with low saturated fatty acid (SFA) content and high-nutritional profiles, monoglyceride (MG) oleogels were produced using oils rich in polyunsaturated fatty acids (PUFA), i.e. fatty acids that are themselves bioactive compounds. The effects of the MG concentration (6% and 10%, w/w) and oil type—sunflower, chia, flaxseed, soybean, and sesame—on nutritional and structural, rheological, mechanical, and thermal properties of oleogels were investigated. Overall, all oleogels were structurally stable gels with textural characteristics that can mimic the functionality of spreadable margarines. In addition, by changing the oil type and MG concentration, the properties studied could be tailored. Particularly, chia and flaxseed oleogels, exhibiting superior nutritional quality based on their low atherogenic and thrombogenic indexes and higher PUFA/SFA ratios, showed the highest hardness (up to 48% higher) and oil binding capacity (OBC). This enhanced functionality was attributed to their microstructural characteristics, featuring smaller crystals, and the unrefined nature of these oils. Notably, flaxseed oleogels with 6% MG yielded OBC values of 99.5%, similar to all samples containing 10% MG. Furthermore, results from a low-temperature Rancimat test suggested that MG crystalline structure may protect chia oil against oxidation. Our findings indicate that PUFA-rich oils have potential for developing health-conscious ingredients with acceptable technological characteristics.

Nanotechnology-based Intranasal Drug Delivery Systems: A Review

An experimental study has focused on developing a different approach to systemic oral along with parenteral administration in order to overcome their common drawbacks, including hepatic first-pass, which reduces drug bioavailability following oral administration, off-target effects, low patient compliance, along with a slow onset of pharmacological action through first-aid cases. Novel drug delivery systems (DDS), mostly composed of polymers and biocompatible lipid materials, have significantly boosted this sector in recent years. The previously intranasal (IN) method of delivery is an acceptable non-invasive option. It is ideal for self-administration since the medication quickly enters the circulation, eliminating the initial pass effect, and it may additionally reach the brain’s cortex directly by crossing the blood-brain barrier (BBB). The combination of the IN route alongside DDS can, therefore, become a successful method for regulated drug administration, particularly when a rapid impact is sought or required. This study seeks to analyze the scientific literature on IN-DDS and its various routes for consumption (systemic, topical, pulmonary, and nose-to-brain). In this regard, the intranasal route offers a viable pathway for medication delivery reaching the brain because of its distinct anatomical characteristics. Nanoparticle-based technologies, in particular, have proven a remarkable ability to overcome the limitations of the intranasal route to induce drug accumulation throughout the brain despite avoiding systemic dissemination

Abstract 2046: Targeting cellular models of glioblastoma versus non-target and off-target cell populations using U87-MG membrane lipid-modified nanoliposomes

Abstract Background: Glioblastoma Multiform (GBM) is an aggressive and malignant form of brain cancer known for its invasiveness and significant heterogenicity. The majority of GBM cases are linked to genetic mutations (ie. TP53, EGFR, and PTEN), which disrupt the normal regulation of cell growth and division, resulting in uncontrolled cell proliferation. The utilization of nanoparticles presents a promising approach for addressing the complexities associated with selective drug delivery to GMB and treatment. The purpose of this study was to investigate the effect of including U87-MG membrane lipid extracts in nanoliposomes using target, non-target, and normal healthy cellular populations in vitro. Methods: The nanoliposomes employed for the experiments included various ratios of U87-MG lipid extracts (lipids derived from U87-MG cells), DOPC, Cholesterol, and DPPE-Rhodamine for fluorescence studies. The particle size and zeta potential values were measured and monitored throughout for consistency. Fluorescence intensity values (arbitrary units) were used to assess extent of cell binding, and uptake at the various time points. In vitro studies were employed to evaluate the cellular uptake activity of U87-MG-modified nanoliposome preparations using mixed ratios and compositions of lipid materials. Cell lines employed were, LN-18 (human glioma), T98G (human glioma), U87-MG (human glioma), 4TI (murine breast), and HBEC-5i (normal healthy) cells. Results: The average size for the nanoliposomes (with and without lipid extract) fell within the range of 110 to 220 nm, while the zeta potential for the CLENs was negatively-charged. In vitro studies revealed that the inclusion of U87MG lipid extract in nanoliposomes increased cellular uptake in glioma cells when compared to control. Current investigations focus on different microenvironments, including non-target and off target cell populations. The findings from the cellular uptake analyses to date suggest that the in vitro cellular uptake of the CLENs varied in accordance with the total lipid extract content for all cell lines. Citation Format: Kaylee Janton, Duha Baamir, Aesha Patel, Sheren Boco, Robert Campbell. Targeting cellular models of glioblastoma versus non-target and off-target cell populations using U87-MG membrane lipid-modified nanoliposomes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2046.

Purification of lipid oil using ion exchange resins

AbstractOil upgrading technologies for fuel production from second-generation feedstocks require pretreatments, such as the removal of ash metals in crude oil, to improve the catalytic performance in the process. The aim of this work was to purify lipid crude oil, derived from black soldier fly larvae (BSFL), from calcium by dry washing using ion exchange resins. Commercially available ion exchange resins suitable for organic liquids, namely GF 202 and Amberlyst 15DRY (AL 15), were selected for the purification experiments. The lipid material dissolved in nonanoic acid in different concentrations of mixtures was passed through a resin-filled plug-flow reactor at 50 °C and 75 °C with a liquid hourly space velocity (LHSV) of 4 h−1. The oil samples were analyzed for calcium using inductively coupled plasma-optical emission spectrometry, while the resin surfaces were examined by scanning electron microscopy. AL 15 showed a better overall performance and led to a case where over 99% of calcium was removed. Graphical abstract

Navigating the challenges of lipid nanoparticle formulation: the role of unpegylated lipid surfactants in enhancing drug loading and stability.

Lipid nanoparticles have proved an attractive approach for drug delivery; however, the challenges of optimising formulation stability and increasing drug loading have limited progression. In this work, we investigate the role of unpegylated lipid surfactants (helper lipids) in nanoparticle formation and the effect of blending helper lipids with pegylated lipid surfactants on the formation and stability of lipid-based nanoparticles by nanoprecipitation. Furthermore, blends of unpegylated/pegylated lipid surfactants were examined for ability to accommodate higher drug loading formulations by means of a higher weight percentage (wt%) of drug relative to total mass of formulation components (i.e. drug, surfactants and lipids). Characterisation included evaluation of particle diameter, size distribution, drug loading and nanoformulation stability. Our findings demonstrate that the addition of unpegylated lipid surfactant (Lipoid S100) to pegylated lipid surfactant (Brij S20) enhances stability, particularly at higher weight percentages of the core material. This blending approach enables drug loading capacities exceeding 10% in the lipid nanoparticles. Notably, Lipoid S100 exhibited nucleating properties that aided in the formation and stabilisation of the nanoparticles. Furthermore, we examined the incorporation of a model drug into the lipid nanoparticle formulations. Blending the model drug with the core material disrupted the crystallinity of the core, offering additional potential benefits in terms of drug release and stability. This comprehensive investigation provides valuable insights into the interplay between surfactant properties, core material composition, and nanoparticle behaviour. The study enhances our understanding of lipid materials and offers guidance for the design and optimisation of lipid nanoparticle formulations.

Intracranial progression of the epidermoid cyst to a white epidermoid cyst in a pediatric patient: a case report

BackgroundEpidermoid cysts are rare benign lesions that originate from remnants of ectodermal epithelial tissue, particularly infrequent in the pediatric population. They exhibit characteristic imaging features, with occasional variations leading to the development of a “white” epidermoid cyst. This transformation results from the presence of protein and lipid material within the cyst, causing intrinsic hyperintensity in T1-weighted images, signal hypointensity in T2-weighted images, and a bright signal in diffusion-weighted imaging.Case presentationWe describe the case of a 5-year-old Latina pediatric patient initially diagnosed with a typical epidermoid cyst. After 13 years of follow-up, this typical epidermoid cyst underwent a transformation, becoming a “white” epidermoid cyst.ConclusionsEpidermoid cysts are rare intracranial lesions. The term “white epidermoid cyst” does not denote a variant; it represents a distinct transformation within an epidermoid cyst due to liquid and protein accumulation. This transformation should be considered in cases with specific imaging characteristics.

Encapsulation of vitamin D3 using rhamnolipids-based nanostructured lipid carriers.

This work had as main objective to encapsulate vitamin D3 (VD3) into nanostructured lipid carriers (NLCs) using rhamnolipids as surfactant. Glycerol monostearate and medium chain triglycerides with 2.625 % of VD3 were used as lipid materials. The three formulations of NLCs with VD3 (NLCs+VD3) were composed by 99 % of aqueous phase, 1 % of lipid phase and 0.05 % of surfactant. The difference between them was the ratio of solid:liquid in lipid phase. The NLCs+VD3 sizes ranged between 92.1 and 108.1nm. The most stable formulation maintaining their caracteristics for 60days at 4°C. The NLCs+VD3 cytotoxicity demonstrated that concentrations of 0.25mg/mL or lower up had a good biocompatibility in vitro. During the in vitro digestion, formulations with lower sizes and higher content on solid lipid had higher lipolysis rate and consequently higher VD3 bioaccessibility. The rhamnolipids-based NLCs are a good option for the encapsulation of VD3.

An Ionizable Lipid Material with a Vitamin E Scaffold as an mRNA Vaccine Platform for Efficient Cytotoxic T Cell Responses.

RNA vaccines based on lipid nanoparticles (LNPs) with in vitro transcribed mRNA (IVT-mRNA) encapsulated are now a currently successful but still evolving modality of vaccines. One of the advantages of RNA vaccines is their ability to induce CD8+ T-cell-mediated cellular immunity that is indispensable for excluding pathogen-infected cells or cancer cells from the body. In this study, we report on the development of LNPs with an enhanced capability for inducing cellular immunity by using an ionizable lipid with a vitamin E scaffold. An RNA vaccine that contained this ionizable lipid and an IVT-mRNA encoding a model antigen ovalbumin (OVA) induced OVA-specific cytotoxic T cell responses and showed an antitumor effect against an E.G7-OVA tumor model. Vaccination with the LNPs conferred protection against lethal infection by Toxoplasma gondii using its antigen TgPF. The vitamin E scaffold-dependent type I interferon response was important for effector CD8+ T cell differentiation induced by the mRNA-LNPs. Our findings also revealed that conventional dendritic cells (cDCs) were essential for achieving CD8+ T cell responses induced by the mRNA-LNPs, while the XCR1-positive subset of cDCs, cDC1 specialized for antigen cross-presentation, was not required. Consistently, the mRNA-LNPs were found to selectively transfect another subset of cDCs, cDC2 that had migrated from the skin to lymph nodes, where they could make vaccine-antigen-dependent contacts with CD8+ T cells. The findings indicate that the activation of innate immune signaling by the adjuvant activity of the vitamin E scaffold and the expression of antigens in cDC2 are important for subsequent antigen presentation and the establishment of antigen-specific immune responses.

Tailoring the release of drugs having different water solubility by hybrid polymer-lipid microparticles with a biphasic structure

The aim of this study is to investigate the potential of hybrid polymer-lipid microparticles with a biphasic structure (b-MPs) as drug delivery system. Hybrid b-MPs of Compritol®888 ATO as main lipid constituent of the shell and polyethylene glycol 400 as core material were produced by an innovative solvent-free approach based on spray congealing. To assess the suitability of hybrid b-MPs to encapsulate various types of APIs, three model drugs (fluconazole, tolbutamide and nimesulide) with extremely different water solubility were loaded into the polymeric core. The hybrid systems were characterized in terms of particle size, morphology and physical state. Various techniques (e.g. optical, Confocal Raman and Scanning Electron Microscopy) were used to investigate the influence of the drugs on different aspects of the b-MPs, including external and internal morphology, properties at the lipid/polymer interface and drug distribution. Hybrid b-MPs were suitable for the encapsulation of all drugs (encapsulation efficiency > 90 %) regardless the drug hydrophobic/hydrophilic properties. Finally, the drug release behaviors from hybrid b-MPs were studied and compared with traditional solid lipid MPs (consisting of only the lipid carrier). Due to the combination of lipid and polymeric materials, hybrid b-MPs showed a wide array of release profiles that depends on their composition, the type of loaded drug, the drug loading amount and location, providing a versatile platform and allowing the formulators to finely balance the release performance of drugs intended for oral administration. Overall, the study demonstrates that hybrid, solvent-free b-MPs produced by spray congealing are an extremely versatile delivery platform able to efficiently encapsulate and release very different types of drug compounds.

Functionalized nanoparticles crossing the brain-blood barrier to target glioma cells.

Glioma is the most common tumor of the central nervous system (CNS), with a 5-year survival rate of <35%. Drug therapy, such as chemotherapeutic and immunotherapeutic agents, remains one of the main treatment modalities for glioma, including temozolomide, doxorubicin, bortezomib, cabazitaxel, dihydroartemisinin, immune checkpoint inhibitors, as well as other approaches such as siRNA, ferroptosis induction, etc. However, the filter function of the blood-brain barrier (BBB) reduces the amount of drugs needed to effectively target CNS tumors, making it one of the main reasons for poor drug efficacies in glioma. Thus, finding a suitable drug delivery platform that can cross the BBB, increase drug aggregation and retainment in tumoral areas and avoid accumulation in non-targeted areas remains an unsolved challenge in glioma drug therapy. An ideal drug delivery system for glioma therapy should have the following features: (1) prolonged drug life in circulation and effective penetration through the BBB; (2) adequate accumulation within the tumor (3) controlled-drug release modulation; (4) good clearance from the body without significant toxicity and immunogenicity, etc. In this regard, due to their unique structural features, nanocarriers can effectively span the BBB and target glioma cells through surface functionalization, providing a new and effective strategy for drug delivery. In this article, we discuss the characteristics and pathways of different nanocarriers for crossing the BBB and targeting glioma by listing different materials for drug delivery platforms, including lipid materials, polymers, nanocrystals, inorganic nanomaterials, etc.

Lipid-based Liquid Crystalline Phases for Biocompatible and Versatile Drug Delivery

The purpose of the paper was to overview the liquid crystalline phases that can be prepared with various lipids and to assess their characteristics as drug delivery systems for drugs to be administered to various routes. Glyceryl monooleate (GMO) was most frequently employed to deliver the drugs to topical, transdermal, oral, buccal and parenteral routes. In addition to bulk phase such as lamellar and cubic liquid crystalline phases, nano-sized cubosomes of GMO have offered a wide range of chances to administer drugs more precisely to oral and parenteral routes. In addition to GMO different types of lipids including phospholipids, triglycerides, fatty acids and cholesterol were able to form liquid crystalline phases even though most studies employing other lipids than GMO were focused on revealing their phase behaviors and physicochemical characteristics. However, it was expected that more research attempts will be made on utilizing new class of liquid crystalline phases that can be formed with various lipids. Based on the outcome published to date, more versatile drug delivery can be possible if new lipid materials can be developed and used to organize unique molecular orders suitable for a difficult-to-carry drugs.

The 20th Century Wall Paintings in the Chapel of the Fallen in Parma Cathedral (Italy): Scientific Investigations for a Correct Conservation Project

In this work, we present a diagnostic study carried out on 20th century wall paintings in the Chapel of the Fallen of the Great War in the Cathedral of Parma (Italy). The Chapel was painted in the two-year period of 1921–1922 and has been recently restored. The paintings were investigated in order to study the technique used by the painter, Biagio Biagetti (Porto Recanati, 1877–Macerata, 1948) and their state of conservation. A total of twelve micro-fragments of the painting layers were sampled and investigated using different techniques. Raman spectroscopy revealed the large amount of different pigments used for each hue, many of them being synthetic materials. SEM/EDS analysis showed that the mortar was an aerial lime obtained from calcium carbonate mixed with a small amount of clay. Organic materials were identified by FTIR spectroscopy. GC/MS investigations revealed lipid and proteinaceous materials in the examined specimens; the lipid fraction, however, is not attributable to the presence of drying oils. From the determination of the amino acid content, it became apparent that the proteinaceous fraction is due to the combination of egg and animal glue; this allowed us to infer the use of “a secco” techniques, confirming the visual impressions of the restorer. The results obtained have contributed to the definition of the conservation project in its various phases.

Asteroid bodies and autophagy.

Asteroid bodies are star-shaped inclusions in the cytoplasm of multinucleated giant cells. Asteroid bodies are not pathognomonic for a single disease, as these structures may be encountered in various granulomatous inflammatory conditions, including sarcoidosis, foreign body-type granulomas, and mycotic granulomas. In hematoxylin and eosin-stained light-microscopic preparations, asteroid bodies are strongly eosinophilic and surrounded by a halo of small clear vacuoles, as shown in Figures 1-3. Their bright red color reflects a high protein content, whereas the halo of clear vacuoles likely represents an artifact due to dissolved lipid material. In the past, asteroid bodies have intrigued several researchers and electron microscopy has been applied to unravel the composition and pathogenesis of this most peculiar microscopic phenomenon. About 40 years ago, it was discovered that the shape of asteroid bodies in Langhans-type giant cells is determined by the structure of the cytosphere, an ordered central subcellular structure consisting of a pool of centrioles, radiating microtubules, and radially arranged Golgi networks.1 In the 1990s, other investigators observed that the halo of clear vacuoles around the asteroid body contains loosely arranged myelin membranes, possibly representing excessive remnants of cellular membranes formed after the fusion of activated histiocytes.2 Notably, these seminal electron microscopic studies of asteroid bodies may point towards a possible role of autophagy in the formation of asteroid bodies. Herein, it is hypothesized that these structures contain aggregates of misfolded proteins and damaged organelles transported along a microtubular network and delivered to lysosomes in an organizing center close to the Golgi complex. In this pilot immunohistochemical study, evidence is provided that asteroid bodies contain both the autophagy receptor p62 (also known as SQSTM1) and the autophagosome marker LC3. For technical details of immunohistochemistry (IHC) please see the study by Te Rijdt et al.3 At the molecular level, the interaction of LC3 with p62 facilitates the fusion of autophagosomes with lysosomes during the degradation of protein aggregates or cell organelles. Notably, LC3-positive granules become larger in cells where autophagosome formation is abrogated.4 The first case concerns an annular elastolytic granuloma, a rare granulomatous skin disease of unknown etiology and pathogenesis, in which degraded elastic fibers are phagocytized by histiocytes and multinucleated giant cells. In this case, easily discerned asteroid bodies (Figure 1A) contained both p62 (Figure 1B) and granular deposits of LC3. The second case represents a foreign body-type granulomatous disease, in which granulomas had formed around abundant silicone material that had leaked from an elbow prosthesis into surrounding soft tissue (particle disease). In this case, many asteroid bodies were seen in the cytoplasm of multinucleated giant cells that had ingested the silicone rubber (Figure 2A). Here, asteroid bodies also contained both p62 and particularly large granules with LC3 (Figure 2B). Third, Figure 3 represents two different cases of cutaneous sarcoidosis, a disease in which Langhans-type giant cells with characteristic asteroid bodies usually are rare (Figure 3A). As in the other granulomatous inflammatory disorders presented herein, the asteroid body was surrounded by LC3-positive material (Figure 3B). In conclusion, ultrastructural studies published many decades ago have shown that the stellate shape of asteroid bodies is determined by the radial arrangement of a microtubular network around the so-called cytosphere. In this pilot study, IHC staining for the autophagy markers LC3 and p62 indicated that autophagy may play a role in the morphological appearance of asteroid bodies. For instance, it is conceivable that the dynamics of autophagy contribute to the bright red color of aggregated proteins around asteroid cores in hematoxylin and eosin-stained light-microscopic preparations. Moreover, given the remarkably large size of LC3-containing granules found in foreign body-type granulomas, it seems likely that autophagy may become impaired during a rapid cellular turnover when mononuclear histiocytes fuse into multinucleated giant cells. I have no problem concerning data sharing, including the complete text and all three figures.

Identification of pigments and binders of a 17th century mural painting (Bolivia). New report on pigments associated with Andean minerals

Research on the materiality of Andean Colonial artistic heritage contributes to the knowledge on the cultural and social history of the region. In this work we present the results of an interdisciplinary and multi-analytical investigation on a mural painting of the church of Curahuara de Carangas in Bolivia. This painting has been hidden for years behind the main 18th century wooden altarpiece. Its stylistic and pictorial characteristics place it in the early 17th century (1608), while other mural paintings of the temple correspond to a second stage, by 1777. Pigments were identified by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and Raman micro-spectroscopy. The application of imaging methods not only allowed the identification and characterization of the materials but also gave information on the manufacturing technique of this mural painting. An outstanding finding in our work was the identification of a mixture of two copper minerals, atacamite [Cu2Cl(OH)3] and antlerite [Cu3SO4(OH)4], as the green pigment. Atacamite and antlerite have been separately identified in a polychrome sculpture and a mural painting, respectively, but this is the first report on their use as a mixture. Other pigments identified in the mural painting were haematite, azurite, red lead, cinnabar, gypsum, cerussite, orpiment, and carmine lake. These results, together with the identification of traces of minerals of the region, indicate the use of local materials by Andean painters from the early Colonial period. This suggests continuity in the cultural practices from pre-Hispanic times and an appropriation and reformulation of traditional European painting practices adapted to new resources. Analysis of lipid and protein materials by gas-chromatography coupled to mass spectrometry (GC–MS) indicated the use of a secco painting technique involving the use of egg as pigment binder. Identification of animal glue suggested its use as the plaster primer. The knowledge of the materials and the painting technique of this artwork will allow the identification of similarities and differences with other mural paintings in churches of the Andean region and give useful information for conservation and preservation of this artwork.