Convergently evolved placental villi show multiscale structural adaptations to differential placental invasiveness.

Despite having a single evolutionary origin and conserved function, the mammalian placenta exhibits radical structural diversity. The evolutionary drivers and functional consequences of placental structural diversity are poorly understood. Humans and equids both display treelike placental villi, however these villi evolved independently and exhibit starkly different levels of invasiveness into maternal tissue (i.e. the number of maternal tissue layers between placental tissue and maternal blood). The villi in these species therefore serve as a compelling evolutionary case study to explore whether placentas have developed structural adaptations to respond to the challenge of reduced nutrient availability in less invasive placentas. Here, we use three-dimensional X-ray microfocus computed tomography and electron microscopy to quantitatively evaluate key structures involved in exchange in human and equid placental villi. We find that equid villi have a higher surface area to volume ratio and deeper trophoblastic vessel indentation than human villi. Using illustrative computational models, we propose that these structural adaptations have evolved in equids to boost nutrient transfer to compensate for reduced invasiveness into maternal tissue. We discuss these findings in relation to the 'maternal-fetal conflict hypothesis' of placental evolution.

A Systematic Review and Meta-Analysis of the Pathology Underlying Aneurysm Enhancement on Vessel Wall Imaging.

Intracranial aneurysms are common, but only a minority rupture and cause subarachnoid haemorrhage, presenting a dilemma regarding which to treat. Vessel wall imaging (VWI) is a contrast-enhanced magnetic resonance imaging (MRI) technique used to identify unstable aneurysms. The pathological basis of MR enhancement of aneurysms is the subject of debate. This review synthesises the literature to determine the pathological basis of VWI enhancement. PubMed and Embase searches were performed for studies reporting VWI of intracranial aneurysms and their correlated histological analysis. The risk of bias was assessed. Calculations of interdependence, univariate and multivariate analysis were performed. Of 228 publications identified, 7 met the eligibility criteria. Individual aneurysm data were extracted for 72 out of a total of 81 aneurysms. Univariate analysis showed macrophage markers (CD68 and MPO, p = 0.001 and p = 0.002), endothelial cell markers (CD34 and CD31, p = 0.007 and p = 0.003), glycans (Alcian blue, p = 0.003) and wall thickness (p = 0.030) were positively associated with enhancement. Aneurysm enhancement therefore appears to be associated with inflammatory infiltrate and neovascularisation. However, all these markers are correlated with each other, and the literature is limited in terms of the numbers of aneurysms analysed and the parameters considered. The data are therefore insufficient to determine if these associations are independent of each other or of aneurysm size, wall thickness and rupture status. Thus, the cause of aneurysm-wall enhancement currently remains unknown.

Tailored Sticky Solutions: 3D-Printed Miconazole Buccal Films for Pediatric Oral Candidiasis.

In this research, 3D-printed antifungal buccal films (BFs) were manufactured as a potential alternative to commercially available antifungal oral gels addressing key considerations such as ease of manufacturing, convenience of administration, enhanced drug efficacy and suitability of paediatric patients. The fabrication process involved the use of a semi-solid extrusion method to create BFs from zein-Poly-Vinyl-Pyrrolidone (zein-PVP) polymer blend, which served as a carrier for drug (miconazole) and taste enhancers. After manufacturing, it was determined that the disintegration time for all films was less than 10 min. However, these films are designed to adhere to buccal tissue, ensuring sustained drug release. Approximately 80% of the miconazole was released gradually over 2 h from the zein/PVP matrix of the 3D printed films. Moreover, a detailed physicochemical characterization including spectroscopic and thermal methods was conducted to assess solid state and thermal stability of film constituents. Mucoadhesive properties and mechanical evaluation were also studied, while permeability studies revealed the extent to which film-loaded miconazole permeates through buccal tissue compared to commercially available oral gel formulation. Histological evaluation of the treated tissues was followed. Furthermore, in vitro antifungal activity was assessed for the developed films and the commercial oral gel. Finally, films underwent a two-month drug stability test to ascertain the suitability of the BFs for clinical application. The results demonstrate that 3D-printed films are a promising alternative for local administration of miconazole in the oral cavity.

X-ray Micro-Computed Tomography for Nondestructive Three-Dimensional (3D) X-ray Histology.

Historically, micro-computed tomography (µCT) has been considered unsuitable for histologic analysis of unstained formalin-fixed, paraffin-embedded soft tissue biopsy specimens because of a lack of image contrast between the tissue and the paraffin. However, we recently demonstrated that µCT can successfully resolve microstructural detail in routinely prepared tissue specimens. Herein, we illustrate how µCT imaging of standard formalin-fixed, paraffin-embedded biopsy specimens can be seamlessly integrated into conventional histology workflows, enabling nondestructive three-dimensional (3D) X-ray histology, the use and benefits of which we showcase for the exemplar of human lung biopsy specimens. This technology advancement was achieved through manufacturing a first-of-kind µCT scanner for X-ray histology and developing optimized imaging protocols, which do not require any additional sample preparation. 3D X-ray histology allows for nondestructive 3D imaging of tissue microstructure, resolving structural connectivity and heterogeneity of complex tissue networks, such as the vascular network or the respiratory tract. We also demonstrate that 3D X-ray histology can yield consistent and reproducible image quality, enabling quantitative assessment of a tissue's 3D microstructures, which is inaccessible to conventional two-dimensional histology. Being nondestructive, the technique does not interfere with histology workflows, permitting subsequent tissue characterization by means of conventional light microscopy-based histology, immunohistochemistry, and immunofluorescence. 3D X-ray histology can be readily applied to a plethora of archival materials, yielding unprecedented opportunities in diagnosis and research of disease.

Synergistic Antitumor Potency of a Self-Assembling Peptide Hydrogel for the Local Co-delivery of Doxorubicin and Curcumin in the Treatment of Head and Neck Cancer.

Combination therapy has been conferred with manifold assets leveraging the synergy of different agents to achieve a sufficient therapeutic outcome with lower administered drug doses and reduced side effects. The therapeutic potency of a self-assembling peptide hydrogel for the co-delivery of doxorubicin and curcumin was assessed against head and neck cancer cells. The dual loaded peptide hydrogel enabled control over the rate of drug release based on drug's aqueous solubility. A significantly enhanced cell growth inhibitory effect was observed after treatment with the combination drug-loaded hydrogel formulations compared to the respective combination drug solution. The synergistic pharmacological effect of selected hydrogel formulations was further confirmed with enhanced apoptotic cell response, interference in cell cycle progression, and significantly altered apoptotic/anti-apoptotic gene expression profiles obtained in dose levels well below the half-maximal inhibitory concentrations of both drugs. The in vivo antitumor efficacy of the drug-loaded peptide hydrogel formulation was confirmed in HSC-3 cell-xenografted severe combined immunodeficient mice and visualized with µCT imaging. Histological and terminal deoxynucleotidyl transferase dUTP nick end labeling assay analyses of major organs were implemented to assess the safety of the topically administered hydrogel formulation. Overall, results demonstrated the therapeutic utility of the dual drug-loaded peptide hydrogel as a pertinent approach for the local treatment of head and neck cancer.

Controlled Release of 5-Fluorouracil from Alginate Beads Encapsulated in 3D Printed pH-Responsive Solid Dosage Forms.

Three-dimensional printing is being steadily deployed as manufacturing technology for the development of personalized pharmaceutical dosage forms. In the present study, we developed a hollow pH-responsive 3D printed tablet encapsulating drug loaded non-coated and chitosan-coated alginate beads for the targeted colonic delivery of 5-fluorouracil (5-FU). A mixture of Eudragit® L100-55 and Eudragit® S100 was fabricated by means of hot-melt extrusion (HME) and the produced filaments were printed utilizing a fused deposition modeling (FDM) 3D printer to form the pH-responsive layer of the tablet with the rest comprising of a water-insoluble poly-lactic acid (PLA) layer. The filaments and alginate particles were characterized for their physicochemical properties (thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction), their surface topography was visualized by scanning electron microscopy and the filaments' mechanical properties were assessed by instrumented indentation testing and tensile testing. The optimized filament formulation was 3D printed and the structural integrity of the hollow tablet in increasing pH media (pH 1.2 to pH 7.4) was assessed by means of time-lapsed microfocus computed tomography (µCT). In vitro release studies demonstrated controlled release of 5-FU from the alginate beads encapsulated within the hollow pH-sensitive tablet matrix at pH values corresponding to the colonic environment (pH 7.4). The present study highlights the potential of additive manufacturing in fabricating controlled-release dosage forms rendering them pertinent formulations for further in vivo evaluation.

Preparation and characterization of bioadhesive microparticles comprised of low degree of quaternization trimethylated chitosan for nasal administration: effect of concentration and molecular weight.

Toward the development of microparticulate carriers for nasal administration, N-trimethylchitosan chloride (TMC) of low molecular weight (LMW) and high molecular weight (HMW) and low degree of quaternization (16% and 27%, respectively) was co-formulated into microparticles comprising of dipalmatoylphosphatidylcholine (DPPC) and poly(lactic-co-glycolic) acid (PLGA) via the spray-drying technique. The chitosan derivatives were characterized by means of nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and Fourier transfrom infrared (FTIR) spectroscopy. The size and morphology of the produced microparticles were assessed by scanning electron microscopy (SEM), whereas their mucoadhesive properties were investigated by means of atomic force microscopy-force spectroscopy (AFM-FS). The results showed that microparticles exhibit mucoadhesion when TMC is present on their surface above a threshold of TMC (>0.3% w/w).

The role of nanoscale toughening mechanisms in osteoporosis.

Strength is the most widely reported parameter with regards to bone failure. However, bone contains pre-existing damage and stress concentration sites, perhaps making measures of fracture toughness more indicative of the resistance of the tissue to withstand fracture. Several toughening mechanisms have been identified in bone, prominently, at the microscale. More recently, nanoscale toughness mechanisms, such as sacrificial-bonds and hidden-length or dilatational band formation, mediated by noncollagenous proteins, have been reported. Absence of specific noncollagenous proteins results in lowered fracture toughness in animal models. Further, roles of several other, putative influencing, factors such as closely bound water, collagen cross-linking and citrate bonds in bone mineral have also been proposed. Yet, it is still not clear if and which mechanisms are hallmarks of osteoporosis disease and how they influence fracture risk. Further insights on the workings of such influencing factors are of high importance for developing complementary diagnostics and therapeutics strategies.

In silico simulations of diffusion tensors and tortuosity in cells grown on 3D-printed scaffolds for tissue engineering.

Tissue engineering is set to revolutionise regenerative medicine, drug discovery, and cancer biology. For this to succeed, improved 3D imaging methods that penetrate non-invasively into the developing tissue is fundamental to guide the design of new and improved 3D supports. In particular, it is very important to characterise the time- and space-heterogeneous pore network that continuously changes as the tissue grows, since delivery of nutrients and removal of waste is key to avoid the development of necrotic tissues. In this paper, we combine high-resolution microfocus Computed Tomography (µCT) imaging and in silico simulations to calculate the diffusion tensor of molecules diffusing in the actual pore structure of a tissue grown on 3D-printed plastic scaffolds. We use such tensors to derive information about the changing pore network and derive tortuosity, a key parameter to understand how pore interconnection changes with cell proliferation. Such information can be used to improve the design of 3D-printed supports as well as to validate and improve cell culture protocols.

Three-dimensional reconstruction of high latitude bamboo coral via X-ray microfocus Computed Tomography.

The skeletons of long-lived bamboo coral (Family Keratoisididae) are promising archives for deep-water palaeoceanographic reconstructions as they can record environmental variation at sub-decadal resolution in locations where in-situ measurements lack temporal coverage. Yet, detailed three dimensional (3D) characterisations of bamboo coral skeletal architecture are not routinely available and non-destructive investigations into microscale variations in calcification are rare. Here, we provide high-resolution micro-focus computed tomography (µCT) data of skeletal density for two species of bamboo coral (Acanella arbuscula: 5 specimens, voxel size, 15 µm (central branch scans) and 50 µm (complete structure scan); Keratoisis sp.: 4 specimens, voxel size, 15 µm) collected from the Labrador Sea and Baffin Bay deep-water basins, Eastern Canadian Arctic. These data provide reference models useful for developing methods to assess structural integrity and other fine-scale complexities in many biological, geological, and industrial systems. This will be of wider value to those investigating structural composition, arrangement and/or composition of complex architecture within the fields and subdisciplines of biology, ecology, medicine, environmental geology, and structural engineering.

Quantitative microCT imaging of a whole equine placenta and its blood vessel network.

Placental structure is linked to function across morphological scales. In the placenta, changes to gross anatomy, such as surface area, volume, or blood vessel arrangement, are associated with suboptimal physiological outcomes. However, quantifying each of these metrics requires different laborious semi-quantitative methods. Here, we demonstrate how, with minimal sample preparation, whole-organ computed microtomography (microCT) can be used to calculate gross morphometry of the equine placenta and a range of additional metrics, including branching morphometry of placental vasculature, non-destructively from a single dataset. Our approach can be applied to quantify the gross structure of any large mammalian placenta.

Tissue-Engineered Oral Epithelium for Dental Material Testing: Toward In Vitro Biomimetic Models.

Tissue-engineered oral epithelium (ΤΕΟΕ) was developed after comparing various culture conditions, including submerged (SUB) and air-liquid interface (ALI) human cell expansion options. Barrier formation was evaluated via transepithelial electrical resistance (TEER) and calcein permeation via spectrofluorometry. TEOE was further assessed for long-term viability via live/dead staining and development of intercellular connections via transmission electron microscopy. Tissue architecture was evaluated via histochemistry and the expression of pancytokeratin (pCK) via immunohistochemistry. The effect of two commonly used dental resinous monomers on TEOE was evaluated for alterations in cell viability and barrier permeability. ALI/keratinocyte growth factor-supplemented (ALI-KGS) culture conditions led to the formation of an 8-20-layer thick, intercellularly connected epithelial barrier. TEER values of ALI-KGS-developed TEOE decreased compared with all other tested conditions, and the established epithelium intensively expressed pCK. Exposure to dental monomers affected the integrity and architecture of TEOE and induced cellular vacuolation, implicating hydropic degeneration. Despite structural modifications, the permeability of TEOE was not substantially affected after exposure to the monomers. In conclusion, the biological properties of the TEOE mimicking the physiological functional conditions and its value as biocompatibility assessment tool for dental materials were characterized.

Correlative three-dimensional X-ray histology (3D-XRH) as a tool for quantifying mammalian placental structure.

Mammalian placentas exhibit unparalleled structural diversity, despite sharing a common ancestor and principal functions. The bulk of structural studies in placental research has used two-dimensional (2D) histology sectioning, allowing significant advances in our understanding of mammalian placental structure. However, 2D histology sectioning may be limited if it does not provide accurate information of three-dimensional (3D) tissue architecture. Here, we propose correlative 3D X-ray histology (3D-XRH) as a tool with great potential for resolving mammalian placental structures. 3D-XRH involves scanning a formaldehyde-fixed, paraffin embedded (FFPE) tissue block with 3D X-ray microscopy (microCT) prior to histological sectioning to generate a 3D image volume of the embedded tissue piece. The subsequent 2D histology sections can then be correlated back into the microCT image volume to couple histology staining (or immunolabelling) with 3D tissue architecture. 3D-XRH is non-destructive and requires no additional sample preparation than standard FFPE histology sectioning, however the image volume provides 3D morphometric data and can be used to guide microtomy. As such, 3D-XRH introduces additional information to standard histological workflows with minimal effort or disruption. Using primary examples from porcine, bovine, equine, and canine placental samples, we demonstrate the application of 3D-XRH to quantifying placental structure as well as discussing the limitations and future directions of the methodology. The wealth of information derived from 2D histological sectioning in the biomedical, veterinary, and comparative reproductive sciences provides a rich foundation from which 3D-XRH can build on to advance the study of placental structure and function.

A floating 3D printed polypill formulation for the coadministration and sustained release of antihypertensive drugs.

Polypharmacy is a common issue, especially among elderly patients resulting in administration errors and patient inconvenience. Hypertension is a prevalent health condition that frequently leads to polypharmacy, as its treatment typically requires the co-administration of more than one different Active Pharmaceutical Ingredients (API's). To address these issues, floating hollow torus-shaped dosage forms were developed, aiming at providing prolonged gastric retention and sustained drug release. The dosage forms (polypills) containing three anti-hypertensive API's (diltiazem (DIL), propranolol (PRP) and hydrochlorothiazide (HCTZ)) were created via Fused Deposition Modelling 3D printing. A multitude of the dosage forms were loaded into a capsule and the resulting formulation achieved prolonged retention times over a 12-hour period in vitro, by leveraging both the buoyancy of the dosage forms, and the "cheerios effect" that facilitates the aggregation and retention of the dosage forms via a combination of surface tension and shape of the objects. Physicochemical characterization methods and imaging techniques were employed to investigate the properties and the internal and external structure of the dosage forms. Furthermore, an ex vivo porcine stomach model revealed substantial aggregation, adhesion and retention of the 3D printed dosage forms in porcine stomach. In vitro dissolution testing demonstrated almost complete first-order release of PRP and DIL (93.52 % and 99.9 %, respectively) and partial release of HCTZ (65.22 %) in the 12 h timeframe. Finally, a convolution-based single-stage approach was employed in order to predict the pharmacokinetic (PK) parameters of the API's of the formulation and the resemblance of their PK behavior with previously reported data.

Correlative multiscale microCT-SBF-SEM imaging of resin-embedded tissue.

Three-dimensional biological microscopy presents a trade-off between spatial resolution and field of view. Correlative approaches applying multiple imaging techniques to the same sample can therefore mitigate against these trade-offs. Here, we present a workflow for correlative microscopic X-ray microfocus computed tomography (microCT) and serial block face scanning electron microscopy (SBF-SEM) imaging of resin-embedded tissue, using mammalian placental tissue samples as an example. This correlative X-ray and electron microscopy (CXEM) workflow allows users to image the same sample at multiple resolutions, and target the region of interest (ROI) for SBF-SEM based on microCT. We detail the protocols associated with this workflow and demonstrate its application in multiscale imaging of horse placental villi and ROI selection in the labyrinthine zone of a mouse placenta. These examples demonstrate how the protocol may need to be adapted for tissues with different densities.

68Ga-bisphosphonates for the imaging of extraosseous calcification by positron emission tomography.

Radiolabelled bisphosphonates (BPs) and [18F]NaF (18F-fluoride) are the two types of radiotracers available to image calcium mineral (e.g. bone), yet only [18F]NaF has been widely explored for the non-invasive molecular imaging of extraosseous calcification (EC) using positron emission tomography (PET) imaging. These two radiotracers bind calcium mineral deposits via different mechanisms, with BPs chelating to calcium ions and thus being non-selective, and [18F]NaF being selective for hydroxyapatite (HAp) which is the main component of bone mineral. Considering that the composition of EC has been reported to include a diverse range of non-HAp calcium minerals, we hypothesised that BPs may be more sensitive for imaging EC due to their ability to bind to both HAp and non-HAp deposits. We report a comparison between the 68Ga-labelled BP tracer [68Ga]Ga-THP-Pam and [18F]NaF for PET imaging in a rat model of EC that develops macro- and microcalcifications in several organs. Macrocalcifications were identified using preclinical computed tomography (CT) and microcalcifications were identified using µCT-based 3D X-ray histology (XRH) on isolated organs ex vivo. The morphological and mineral analysis of individual calcified deposits was performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). PET imaging and ex vivo analysis results demonstrated that while both radiotracers behave similarly for bone imaging, the BP-based radiotracer [68Ga]Ga-THP-Pam was able to detect EC more sensitively in several organs in which the mineral composition departs from that of HAp. Our results strongly suggest that BP-based PET radiotracers such as [68Ga]Ga-THP-Pam may have a particular advantage for the sensitive imaging and early detection of EC by being able to detect a wider array of relevant calcium minerals in vivo than [18F]NaF, and should be evaluated clinically for this purpose.

3D printing of LEGO® like designs with tailored release profiles for treatment of sleep disorder.

3D printed LEGO®-like designs are an attractive approach for the development of compartmental delivery systems due to their potential for dose personalisation through the customisation of drug release profiles. Additive manufacturing technologies such as Fused Deposition Modelling (FDM) are ideal for the printing of structures with complex geometries and various sizes. This study is a paradigm for the fabrication of 3D printed LEGO® -like tablets by altering the design of the modular units and the filament composition for the delivery of different drug substances. By using a combination of placebo and drug loaded compartments comprising of immediate release (hydroxypropyl cellulose) and pH dependant polymers (hypromellose acetate succinate) we were able to customise the release kinetics of melatonin and caffeine that can potentially be used for the treatment of sleep disorders. The LEGO® -like compartments were designed to achieve immediate release of melatonin followed by variable lag times and controlled release of caffeine.

A high-throughput 3D X-ray histology facility for biomedical research and preclinical applications.

Background: The University of Southampton, in collaboration with the University Hospital Southampton (UHS) NHS Foundation Trust and industrial partners, has been at the forefront of developing three-dimensional (3D) imaging workflows using X-ray microfocus computed tomography (µCT) -based technology. This article presents the outcomes of these endeavours and highlights the distinctive characteristics of a µCT facility tailored explicitly for 3D X-ray Histology, with a primary focus on applications in biomedical research and preclinical and clinical studies. Methods: The UHS houses a unique 3D X-ray Histology (XRH) facility, offering a range of services to national and international clients. The facility employs specialised µCT equipment explicitly designed for histology applications, allowing whole-block XRH imaging of formalin-fixed and paraffin-embedded tissue specimens. It also enables correlative imaging by combining µCT imaging with other microscopy techniques, such as immunohistochemistry (IHC) and serial block-face scanning electron microscopy, as well as data visualisation, image quantification, and bespoke analysis. Results: Over the past seven years, the XRH facility has successfully completed over 120 projects in collaboration with researchers from 60 affiliations, resulting in numerous published manuscripts and conference proceedings. The facility has streamlined the µCT imaging process, improving productivity and enabling efficient acquisition of 3D datasets. Discussion & Conclusions: The 3D X-ray Histology (XRH) facility at UHS is a pioneering platform in the field of histology and biomedical imaging. To the best of our knowledge, it stands out as the world's first dedicated XRH facility, encompassing every aspect of the imaging process, from user support to data generation, analysis, training, archiving, and metadata generation. This article serves as a comprehensive guide for establishing similar XRH facilities, covering key aspects of facility setup and operation. Researchers and institutions interested in developing state-of-the-art histology and imaging facilities can utilise this resource to explore new frontiers in their research and discoveries.

3D Printing of Personalised Carvedilol Tablets Using Selective Laser Sintering.

Selective laser sintering (SLS) has drawn attention for the fabrication of three-dimensional oral dosage forms due to the plurality of drug formulations that can be processed. The aim of this work was to employ SLS with a CO2 laser for the manufacturing of carvedilol personalised dosage forms of various strengths. Carvedilol (CVD) and vinylpyrrolidone-vinyl acetate copolymer (Kollidon VA64) blends of various ratios were sintered to produce CVD tablets of 3.125, 6.25, and 12.5 mg. The tuning of the SLS processing laser intensity parameter improved printability and impacted the tablet hardness, friability, CVD dissolution rate, and the total amount of drug released. Physicochemical characterization showed the presence of CVD in the amorphous state. X-ray micro-CT analysis demonstrated that the applied CO2 intensity affected the total tablet porosity, which was reduced with increased laser intensity. The study demonstrated that SLS is a suitable technology for the development of personalised medicines that meet the required specifications and patient needs.