Modeling the Drug delivery Lifecycle of PLG Nanoparticles Using Intravital Microscopy.

Polylactide-co-glycolide (PLG) nanoparticles hold immense promise for cancer therapy due to their enhanced efficacy and biodegradable matrix structure. Understanding their interactions with blood cells and subsequent biodistribution kinetics is crucial for optimizing their therapeutic potential. In this study, three doxorubicin-loaded PLG nanoparticle systems are synthesized and characterized, analyzing their size, zeta potential, morphology, and in vitro release behavior. Employing intravital microscopy in 4T1-tumor-bearing mice, real-time blood and tumor distribution kinetics are investigated. A mechanistic pharmacokinetic model is used to analyze biodistribution kinetics. Additionally, flow cytometry is utilized to identify cells involved in nanoparticle hitchhiking. Following intravenous injection, PLG nanoparticles exhibit an initial burst release (<1 min) and rapidly adsorb to blood cells (<5 min), hindering extravasation. Agglomeration leads to the clearance of one carrier species within 3 min. In stable dispersions, drug release rather than extravasation remains the dominant pathway for drug elimination from circulation. This comprehensive investigation provides valuable insights into the interplay between competing kinetics that influence the lifecycle of PLG nanoparticles post-injection. The findings advance the understanding of nanoparticle behavior and lay the foundation for improved cancer therapy strategies using nanoparticle-based drug delivery systems.

Initial Leuprolide Acetate Release from Poly(d,l-lactide-co-glycolide) in Situ Forming Implants as Studied by Ultraviolet-Visible Imaging.

The initial drug release from in situ forming implants is affected by factors such as the physicochemical properties of the active pharmaceutical ingredient, the type of the excipients utilized, and the surrounding environment. The feasibility of UV-vis imaging for characterization of the initial behavior of poly(d,l-lactide-co-glycolide) (PLGA)/1-methyl-2-pyrrolidinone (NMP) in situ forming implants was investigated. The in vitro release of leuprolide acetate (LA) and implant formation in real time were monitored using dual-wavelength imaging at 280 and 525 nm, respectively, in matrices based on agarose gel and hyaluronic acid (HA) solution emulating the subcutaneous matrix. Three hours upon injection of the pre-formulation, approximately 15% of the total amount of LA administered was found in the agarose gel, while 5% was released from the implant into the HA solution. Concurrently, more extensive swelling of the implants in the HA solution as compared to implants in the agarose gel was observed. Transport of both LA and the solvent NMP was investigated using UV-vis imaging in a small-scale cell where the geometry of the formulation was controlled, showing a linear correlation between drug release and solvent escape. Light microscopy showed that the microstructures of the resulting implants in agarose gel and HA solution were different, which may be attributed to the different solvent exchange rates. UV imaging was also used to examine the interaction of LA with the release medium by characterizing the diffusion of LA in agarose gel, HA solution, and phosphate buffered saline. The reduced LA diffusivity in HA solution as compared to agarose gel and the LA distribution coefficient in the agarose gel-HA system indicated the presence of interactions between LA and HA. Our findings show that the external environment affects the solvent exchange kinetics for in situ forming implants in vitro, resulting in different types of initial release behavior. UV-vis imaging in combination with biorelevant matrices may offer an interesting approach in the development of in situ forming implant delivery systems.

Modulation Effects of Permanganate and Manganese(II) Ions on the Oscillatory Dynamics in a Bromate-Sulfite Reaction System.

It is important to study nonlinear dynamical systems showing pH and temperature oscillations simultaneously. Here, we systematically investigated the bromate-sulfite reaction in its coupled system. Large-amplitude temperature oscillations could be measured accompanied by the pH oscillations with or without permanganate and manganese(II) ions. The modulation effects on the oscillatory dynamics of the bromate-sulfite reaction system produced by permanganate and manganese(II) ions were investigated in detail. On the one hand, with permanganate, an additional negative pH feedback process between permanganate and bisulfite occurs, leading to weakening the pH positive feedback. The above opposite effects make the period length change unmonotonically when adjusting the permanganate concentration and flow rate. On the other hand, with Mn2+ as the feedback agent, the nonmonotonic change of period was not obvious because it only contained one feedback loop, which can only reinforce negative feedback without affecting positive feedback.

Application of vermillion myocutaneous flap in restoration after lip cancer resection.

To investigate the application of the vermillion myocutaneous flap in restoration after lip cancer resection. From July 2012 to December 2019, six patients with lip cancer admitted in our department were included in this study. Total defect of the whole layer of the lip, accounted for 1/3 to 1/2 of the total length of the lip after tumor resection, were repaired by vermillion myocutaneous flap. For the case defect presenting >1/2 of the total length of the lip, a local rotational flap was designed with vermillion myocutaneous flap compound to repair the defect. At present, the patients were followed up for 6 months to 7 years. There was no tumor recurrence. The aesthetic effects and function of lip after operation were ideal, with satisfactory outcomes. Vermillion myocutaneous flap with the labial artery as the axis was an effective method to restore the anatomical structure and function of the lip. In the presence of a defect area of larger than 1/2 of the length of the whole lip, local skin flap can be used for simultaneous repair in order to achieve satisfactory outcome.

Novel Strategy Utilizing Extracellular Cysteine-Rich Domain of Membrane Receptor for Constructing d-Peptide Mediated Targeted Drug Delivery Systems: A Case Study on Fn14.

The development of proteolysis-resistant d-peptide ligands for targeted drug/gene delivery has been greatly limited, due to the challenge that lies in the chemical synthesis of membrane receptors without altering their structures. In the present research, a novel strategy utilizing self-stabilized extracellular CRD of the membrane receptor was developed to construct d-peptide ligands and their mediated targeted drug delivery systems. Fn14, a cell surface receptor overexpressed in many cancers including pancreatic and triple-negative breast cancers, was selected as the model receptor. Fn14 CRD was synthesized and folded, and used to screen Fn14 binding peptides using phage display (l-peptide) and mirror-image phage display (d-peptide) techniques, respectively. The d-peptide ligand successfully mediated targeted drug delivery to Fn14 positive tumor cells. In addition, the d-peptide possessed better target-binding affinity, stromal barrier permeability, and tumor targeting ability in vivo when conjugated with liposomes. More importantly, d-peptide mediated liposomal paclitaxel delivery significantly inhibited pancreatic tumor growth in a subcutaneous xenograft model and drastically prolonged survival in a lung metastasis of breast cancer mouse model. This study demonstrated that mirror-image phage display based on the CRD of membrane receptor can be a promising strategy to advance active targeted drug delivery via biostable d-peptides.

Highly Selective Targeting of Hepatic Stellate Cells for Liver Fibrosis Treatment Using a d-Enantiomeric Peptide Ligand of Fn14 Identified by Mirror-Image mRNA Display.

Although liver fibrosis is a major public health issue, there is still no effective drug therapy in the clinic. Fibroblast growth factor-inducible 14 (Fn14), a membrane receptor highly specifically expressed in activated hepatic stellate cells (HSCs), is the key driver of liver fibrosis, and thus, it has a great potential as a novel target for the development of effective treatment. Here, we identified a d-enantiomeric peptide ligand of Fn14 through mirror-image mRNA display. This included the chemical synthesis of a d-enantiomer of the target protein (extracellular domain of Fn14), identification of an l-peptide ligand of d-Fn14 using a constructed mRNA peptide library, and identification of a d-enantiomer of the l-peptide, which is a ligand of the natural Fn14 for reasons of symmetry. The obtained d-peptide ligand showed strong binding to Fn14 while maintaining high proteolytic resistance. As a targeting moiety, this d-peptide successfully mediated high selectivity of activated HSCs for liposomal vehicles compared to that of other major cell types in the liver and significantly enhanced the accumulation of liposomes in the liver fibrosis region of a carbon tetrachloride-induced mouse model. Moreover, in combination with curcumin as an encapsulated load, a liposomal formulation conjugated with this d-peptide showed powerful inhibition of the proliferation of activated HSCs and reduced the liver fibrosis to a significant extent in vivo. This Fn14-targeting strategy may represent a promising approach to targeted drug delivery for liver fibrosis treatment. Meanwhile, the mirror-image mRNA display can provide a new arsenal for the development of d-peptide-based therapeutics against a variety of human diseases.

Synthesis of Diastereoenriched Oxazolo[5,4-b]indoles via Catalyst-Free Multicomponent Bicyclizations.

A new and highly eco-friendly approach to diverse and functionalized oxazolo[5,4-b]indoles with good yield and high diastereoselectivity (up to >99:1) has been disclosed from simple and readily available arylglyoxals with cyclic enaminones and amino acids. These microwave-assisted transformations in environmentally compatible ethanol resulted in continuous multiple bond-forming events including C-C, C-N, and C-O bonds, enabling catalyst-free multicomponent bicyclizations to rapidly build up functional N,O-heterocycles.

[Novel liposomal drug delivery system actively targeting Cryptococcus neoformans and elimination of infection].

The purpose of this study is to develop a liposomal drug delivery system actively targeting Cryptococcus neoformans and explore its feasibility in therapy of cryptococcal infection. The specific fungi-binding peptide was screened from 12-mer random phage display library, and linked to PEG-DSPE as the functional material of liposomes. The targeting capability of peptide-modified liposomes were investigated by fungi binding assay in vitro and fluorescence imaging in vivo. Itraconazole as a model drug were then encapsulated in the liposomes and were evaluated in pharmacodynamic test in vitro and for therapeutic effects against cryptococcal meningitis complicated with pulmonary cryptococcosis in vivo. The results showed that the peptide (sequence: NNHREPPDHRTS) could selectively recognize Cryptococcus and effectively mediate the corresponding liposomal formulation to accumulate in the infection site in vivo. This peptide-modified liposome has a small particle size (mean diameter of 88.25 ± 2.43 nm) with a homogeneous distribution and high encapsulation efficiency (88.05 ± 0.25 %) of itraconazole. After intravenous administration, the pathogens were obviously eliminated in lung and brain, and the life-span of model mice were significantly prolonged, suggesting a promising potential of this cryptococcosis targeting strategy.

Understanding the In Vitro-In Vivo Nexus: Advanced correlation models predict clinical performance of liposomal doxorubicin.

In the century of precision medicine and predictive modeling, addressing quality-related issues in the medical supply chain is critical, with 62 % of the disruptions being attributable to quality challenges. This study centers on the development and safety of liposomal doxorubicin, where animal studies alone often do not adequately explain the complex interplay between critical quality attributes and in vivo performances. Anchored in our aim to elucidate this in vitro-in vivo nexus, we compared TLD-1, a novel liposomal doxorubicin delivery system, against the established formulations Doxil® and Lipodox®. Robust in vitro-in vivo correlations (IVIVCs) with excellent coefficients of determination (R2 > 0.98) were obtained in the presence of serum under dynamic high-shear conditions. They provided the foundation for an advanced characterization and benchmarking strategy. Despite the smaller vesicle size and reduced core crystallinity of TLD-1, its release behavior closely resembled that of Doxil®. Nevertheless, subtle differences between the dosage forms observed in the in vitro setting were reflected in the bioavailabilities observed in vivo. Data from a Phase-I clinical trial facilitated the development of patient-specific IVIVCs using the physiologically-based nanocarrier biopharmaceutics model, enabling a more accurate estimation of doxorubicin exposure. This advancement could impact clinical practice by allowing for more precise dose estimation and aiding in the assessment of the interchangeability of generic liposomal doxorubicin.

Bromocriptine protects perilesional spinal cord neurons from lipotoxicity after spinal cord injury.

Recent studies have revealed that lipid droplets accumulate in neurons after brain injury and evoke lipotoxicity, damaging the neurons. However, how lipids are metabolized by spinal cord neurons after spinal cord injury remains unclear. Herein, we investigated lipid metabolism by spinal cord neurons after spinal cord injury and identified lipid-lowering compounds to treat spinal cord injury. We found that lipid droplets accumulated in perilesional spinal cord neurons after spinal cord injury in mice. Lipid droplet accumulation could be induced by myelin debris in HT22 cells. Myelin debris degradation by phospholipase led to massive free fatty acid production, which increased lipid droplet synthesis, ß-oxidation, and oxidative phosphorylation. Excessive oxidative phosphorylation increased reactive oxygen species generation, which led to increased lipid peroxidation and HT22 cell apoptosis. Bromocriptine was identified as a lipid-lowering compound that inhibited phosphorylation of cytosolic phospholipase A2 by reducing the phosphorylation of extracellular signal-regulated kinases 1/2 in the mitogen-activated protein kinase pathway, thereby inhibiting myelin debris degradation by cytosolic phospholipase A2 and alleviating lipid droplet accumulation in myelin debris-treated HT22 cells. Motor function, lipid droplet accumulation in spinal cord neurons and neuronal survival were all improved in bromocriptine-treated mice after spinal cord injury. The results suggest that bromocriptine can protect neurons from lipotoxic damage after spinal cord injury via the extracellular signal-regulated kinases 1/2-cytosolic phospholipase A2 pathway.

Blood-Nanoparticle Interactions Create a Brain Delivery Superhighway for Doxorubicin.

Purpose: This study investigated the brain targeting mechanism of doxorubicin-loaded polybutyl cyanoacrylate (PBCA) nanoparticles, particularly their interactions with the blood-brain barrier (BBB). The BBB protects the brain from drugs in the bloodstream and represents a crucial obstacle in the treatment of brain cancer. Methods: An advanced computer model analyzed the brain delivery of two distinct formulations, Doxil® and surfactant-coated PBCA nanoparticles. Computational learning was combined with in vitro release and cell interaction studies to comprehend the underlying brain delivery pathways. Results: Our analysis yielded a surprising discovery regarding the brain delivery mechanism of PBCA nanoparticles. While Doxil® exhibited the expected behavior, accumulating in the brain through extravasation in tumor tissue, PBCA nanoparticles employed a unique and previously uncharacterized mechanism. They underwent cell hitchhiking, resulting in a remarkable more than 1000-fold increase in brain permeation rate compared to Doxil® (2.59 × 10-4 vs 0.32 h-1). Conclusion: The nonspecific binding to blood cells facilitated and intensified interactions of surfactant-coated PBCA nanoparticles with the vascular endothelium, leading to enhanced transcytosis. Consequently, the significant increase in circulation time in the bloodstream, coupled with improved receptor interactions, contributes to this remarkable uptake of doxorubicin into the brain.

An optimized culture system for efficient derivation of porcine expanded potential stem cells from preimplantation embryos and by reprogramming somatic cells.

Pigs share anatomical and physiological traits with humans and can serve as a large-animal model for translational medicine. Bona fide porcine pluripotent stem cells (PSCs) could facilitate testing cell and drug therapies. Agriculture and biotechnology may benefit from the ability to produce immune cells for studying animal infectious diseases and to readily edit the porcine genome in stem cells. Isolating porcine PSCs from preimplantation embryos has been intensively attempted over the past decades. We previously reported the derivation of expanded potential stem cells (EPSCs) from preimplantation embryos and by reprogramming somatic cells of multiple mammalian species, including pigs. Porcine EPSCs (pEPSCs) self-renew indefinitely, differentiate into embryonic and extra-embryonic lineages, and permit precision genome editing. Here we present a highly reproducible experimental procedure and data of an optimized and robust porcine EPSC culture system and its use in deriving new pEPSC lines from preimplantation embryos and reprogrammed somatic cells. No particular expertise is required for the protocols, which take ~4-6 weeks to complete. Importantly, we successfully established pEPSC lines from both in vitro fertilized and somatic cell nuclear transfer-derived embryos. These new pEPSC lines proliferated robustly over long-term passaging and were amenable to both simple indels and precision genome editing, with up to 100% targeting efficiency. The pEPSCs differentiated into embryonic cell lineages in vitro and teratomas in vivo, and into porcine trophoblast stem cells in human trophoblast stem cell medium. We show here that pEPSCs have unique epigenetic features, particularly H3K27me3 levels substantially lower than fibroblasts.

Spectra analysis of nonuniform FBG-based acousto-optic modulator by using Fourier mode coupling theory.

Fourier mode coupling theory was first employed in the spectral analysis of several nonuniform fiber Bragg grating (FBG)-based acousto-optic modulators (NU-FBG-AOMs) with the effects of Gaussian-apodization (GA), phase shift (PS), and linear chirp (LC). Because of the accuracy and simplicity of the algorithm applied in this model, the modulation performances of these modulators can be acquired effectively and efficiently. Based on the model, the reflected spectra of these modulators were simulated under various acoustic frequencies and acoustically induced strains. The simulation results of the GA-FBG-AOM and PS-FBG-AOM showed that the wavelength spacing between the primary reflection peak and the secondary reflection peak is proportional to the acoustic frequency, and the reflectivity of reflection peaks depends on the acoustically induced strains. But for the LC-FBG-AOM, the wavelength spacing between the neighboring reflection peaks increased linearly and inversely with the acoustic frequency, and the extinction ratio of each peak relates to the acoustically induced strain. These numerical analysis results, which were effectively used in the designs and fabrications of these NU-FBG-AOMs, can broaden the AOM-based application scope and shed light on the performance optimization of optical wavelength-division multiplex system.

SpatialDM for rapid identification of spatially co-expressed ligand-receptor and revealing cell-cell communication patterns.

Cell-cell communication is a key aspect of dissecting the complex cellular microenvironment. Existing single-cell and spatial transcriptomics-based methods primarily focus on identifying cell-type pairs for a specific interaction, while less attention has been paid to the prioritisation of interaction features or the identification of interaction spots in the spatial context. Here, we introduce SpatialDM, a statistical model and toolbox leveraging a bivariant Moran's statistic to detect spatially co-expressed ligand and receptor pairs, their local interacting spots (single-spot resolution), and communication patterns. By deriving an analytical null distribution, this method is scalable to millions of spots and shows accurate and robust performance in various simulations. On multiple datasets including melanoma, Ventricular-Subventricular Zone, and intestine, SpatialDM reveals promising communication patterns and identifies differential interactions between conditions, hence enabling the discovery of context-specific cell cooperation and signalling.

Phytotoxicity and the molecular response in yttrium oxide nanoparticle-treated Arabidopsis thaliana seedlings.

Due to the widespread application of rare earth oxide nanoparticles in various fields, their release into the environment is inevitable, and their potential toxicity and ecological impact have become a concern. Yttrium oxide nanoparticles are important rare earth oxide nanoparticles; however, their impact on plants and the molecular mechanism underlying their influence on plant growth and development are unclear. In this study, we found that yttrium oxide nanoparticles at concentrations exceeding 2 mM significantly inhibited the growth of Arabidopsis seedlings. Using Arabidopsis marker lines for auxin signaling, we found that the application of yttrium oxide nanoparticles resulted in disordered auxin signaling in root cells. Auxin signaling in the cells of the quiescent center and columella stem cells decreased, while auxin signaling in the cells of the stele was enhanced. In addition, trypan blue staining showed that yttrium oxide nanoparticles induced root cell death. Transcriptome analysis showed that the nanoparticles specifically inhibited the expression of lignin synthesis-related genes, activated the MAPK signaling pathway, and enhanced the ethylene and abscisic acid signaling pathways in plants. This study demonstrates the phytotoxicity of yttrium oxide nanoparticles at the molecular level in Arabidopsis, and it provides a new perspective on how plants respond to rare earth oxide stress.

Simulate SubQ: The Methods and the Media.

For decades, there has been a growing interest in injectable subcutaneous formulations to improve the absorption of drugs into the systemic circulation and to prolong their release over a longer period. However, fluctuations in the blood plasma levels together with bioavailability issues often limit their clinical success. This warrants a closer look at the performance of long-acting depots, for example, and their dependence on the complex interplay between the dosage form and the physiological microenvironment. For this, biopredictive performance testing is used for a thorough understanding of the biophysical processes affecting the absorption of compounds from the injection site in vivo and their simulation in vitro. In the present work, we discuss in vitro methodologies including methods and media developed for the subcutaneous route of administration on the background of the most relevant absorption mechanisms. Also, we highlight some important knowledge gaps and shortcomings of the existing methodologies to provide the reader with a better understanding of the scientific evidence underlying these models.

Fecal Microbiota Transplantation Revealed a Pain-related Gut Microbiota Community in Ovariectomized Mice.

Higher sensitivity to pain is a common clinical symptom in postmenopausal females. The gut microbiota (GM) has recently been identified as participating in various pathophysiological processes and may change during menopause and contribute to multiple postmenopausal symptoms. Here, we investigated the possible correlation between GM alteration and allodynia in ovariectomized (OVX) mice. Results showed that OVX mice exhibited allodynia from 7 weeks after surgery compared with sham-operated (SHAM) mice by comparing pain-related behaviors. Fecal microbiota transplantation (FMT) from OVX mice induced allodynia in normal mice while FMT from SHAM mice alleviated allodynia in OVX mice. Microbiome 16S rRNA sequencing and linear discriminant analysis revealed alteration of the GM after OVX. Furthermore, Spearman's correlation analysis showed associations between pain-related behaviors and genera, and further verification identified the possible pain-related genera complex. Our findings provide new insights into the underlying mechanisms of postmenopausal allodynia, and suggest pain-related microbiota community as a promising therapeutic target. PERSPECTIVE: This article provided the evidence of gut microbiota playing essential roles in postmenopausal allodynia. This work intended to offer a guidance for further mechanism investigation into gut-brain axis and probiotics screening for postmenopausal chronic pain.

Modeling digestion, absorption, and ketogenesis after administration of tricaprilin formulations to humans.

At present, tricaprilin is used as a ketogenic source for the management of mild to moderate Alzheimer's disease. After administration of the medium-chain triglyceride, tricaprilin is hydrolyzed to octanoic acid and further metabolized to ketones, acting as an alternative energy substrate for the brain. In this investigation, we developed a physiologically-based biopharmaceutics model simulating in vivo processes following the peroral administration of tricaprilin. The model includes multiple data sources to establish a partially verified framework for the simulation of plasma profiles. The input parameters were identified based on existing literature data and in vitro digestion studies. Model validation was conducted using the data from a phase I clinical trial. A partial parameter sensitivity analysis elucidated various influences on the plasma ketone levels that are mainly responsible for the therapeutic effects of tricaprilin. Based on our findings, we concluded that dispersibility and lipolysis of tricaprilin together with the gastric emptying patterns are limiting ketogenesis, while other steps such as the conversion of octanoic acid to ketone bodies play a minor role only.

Adrenomedullin has a pivotal role in trophoblast differentiation: A promising nanotechnology-based therapeutic target for early-onset preeclampsia.

Early-onset preeclampsia (EOPE) is a severe pregnancy complication associated with defective trophoblast differentiation and functions at implantation, but manifestation of its phenotypes is in late pregnancy. There is no reliable method for early prediction and treatment of EOPE. Adrenomedullin (ADM) is an abundant placental peptide in early pregnancy. Integrated single-cell sequencing and spatial transcriptomics confirm a high ADM expression in the human villous cytotrophoblast and syncytiotrophoblast. The levels of ADM in chorionic villi and serum were lower in first-trimester pregnant women who later developed EOPE than those with normotensive pregnancy. ADM stimulates differentiation of trophoblast stem cells and trophoblast organoids in vitro. In pregnant mice, placenta-specific ADM suppression led to EOPE-like phenotypes. The EOPE-like phenotypes in a mouse PE model were reduced by a placenta-specific nanoparticle-based forced expression of ADM. Our study reveals the roles of trophoblastic ADM in placental development, EOPE pathogenesis, and its potential clinical uses.

Research on FBG-based longitudinal-acousto-optic modulator with Fourier mode coupling method.

Fourier mode coupling model was first applied to achieve the spectra property of a fiber Bragg grating (FBG)-based longitudinal-acousto-optic modulator. Compared with traditional analysis algorithms, such as the transfer matrix method, the Fourier mode coupling model could improve the computing efficiency up to 100 times with a guarantee of accuracy. In this paper, based on the theoretical analysis of this model, the spectra characteristics of the modulator in different frequencies and acoustically induced strains were numerically simulated. In the experiment, a uniform FBG was modulated by acoustic wave (AW) at 12 different frequencies. In particular, the modulator responses at 563 and 885.5 KHz with three different lead zirconate titanate (PZT) loads applied were plotted for illustration, and the linear fitting of experimental data demonstrated a good match with the simulation result. The acoustic excitation of the longitudinal wave is obtained using a conic silica horn attached to the surface of a shear-mode PZT plate paralleled to the fiber axis. This way of generating longitudinal AW with a transversal PZT may shed light on the optimal structural design for the FBG-based longitudinal-acousto-optic modulator.