Injectable Shear-Thinning Hydrogels with Sclerosing and Matrix Metalloproteinase Modulatory Properties for the Treatment of Vascular Malformations

Sac embolization of abdominal aortic aneurysms (AAAs) remains clinically limited by endoleak recurrences. These recurrences are correlated with recanalization due to the presence of endothelial lining and matrix metalloproteinases (MMPs)-mediated aneurysm progression. This study incorporated doxycycline (DOX), a well-known sclerosant and MMPs inhibitor, into a shear-thinning biomaterial (STB)-based vascular embolizing hydrogel. The addition of DOX was expected to improve embolizing efficacy while preventing endoleaks by inhibiting MMP activity and promoting endothelial removal. The results showed that STBs containing 4.5% w/w silicate nanoplatelet and 0.3% w/v of DOX were injectable and had a 2-fold increase in storage modulus compared to those without DOX. STB-DOX hydrogels also reduced clotting time by 33% compared to untreated blood. The burst release of DOX from the hydrogels showed sclerosing effects after 6 h in an ex vivo pig aorta model. Sustained release of DOX from hydrogels on endothelial cells showed MMP inhibition (ca. an order of magnitude larger than control groups) after 7 days. The hydrogels successfully occluded a patient-derived abdominal aneurysm model at physiological blood pressures and flow rates. The sclerosing and MMP inhibition characteristics in the engineered multifunctional STB-DOX hydrogels may provide promising opportunities for the efficient embolization of aneurysms in blood vessels.

Injectable hydrogels for personalized cancer immunotherapies

The field of cancer immunotherapy has shown significant growth, and researchers are now focusing on effective strategies to enhance and prolong local immunomodulation. Injectable hydrogels (IHs) have emerged as versatile platforms for encapsulating and controlling the release of small molecules and cells, drawing significant attention for their potential to enhance antitumor immune responses while inhibiting metastasis and recurrence. IHs delivering natural killer (NK) cells, T cells, and antigen-presenting cells (APCs) offer a viable method for treating cancer. Indeed, it can bypass the extracellular matrix and gradually release small molecules or cells into the tumor microenvironment, thereby boosting immune responses against cancer cells. This review provides an overview of the recent advancements in cancer immunotherapy using IHs for delivering NK cells, T cells, APCs, chemoimmunotherapy, radio-immunotherapy, and photothermal-immunotherapy. First, we introduce IHs as a delivery matrix, then summarize their applications for the local delivery of small molecules and immune cells to elicit robust anticancer immune responses. Additionally, we discuss recent progress in IHs systems used for local combination therapy, including chemoimmunotherapy, radio-immunotherapy, photothermal-immunotherapy, photodynamic-immunotherapy, and gene-immunotherapy. By comprehensively examining the utilization of IHs in cancer immunotherapy, this review aims to highlight the potential of IHs as effective carriers for immunotherapy delivery, facilitating the development of innovative strategies for cancer treatment. In addition, we demonstrate that using hydrogel-based platforms for the targeted delivery of immune cells, such as NK cells, T cells, and dendritic cells (DCs), has remarkable potential in cancer therapy. These innovative approaches have yielded substantial reductions in tumor growth, showcasing the ability of hydrogels to enhance the efficacy of immune-based treatments. STATEMENT OF SIGNIFICANCE: As cancer immunotherapy continues to expand, the mode of therapeutic agent delivery becomes increasingly critical. This review spotlights the forward-looking progress of IHs, emphasizing their potential to revolutionize localized immunotherapy delivery. By efficiently encapsulating and controlling the release of essential immune components such as T cells, NK cells, APCs, and various therapeutic agents, IHs offer a pioneering pathway to amplify immune reactions, moderate metastasis, and reduce recurrence. Their adaptability further shines when considering their role in emerging combination therapies, including chemoimmunotherapy, radio-immunotherapy, and photothermal-immunotherapy. Understanding IHs' significance in cancer therapy is essential, suggesting a shift in cancer treatment dynamics and heralding a novel period of focused, enduring, and powerful therapeutic strategies.

Nanoparticles-based technologies for cholera detection and therapy

Cholera is a waterborne disease caused by Vibrio cholerae bacteria generally transmitted through contaminated food or water sources. Although it has been eradicated in most Western countries, cholera continues to be a highly transmitted and lethal disease in several African and Southeast Asian countries. Unfortunately, current diagnostic methods for cholera have challenges including high cost or delayed diagnoses that can lead to increased disease transmission during pandemics, while current treatments such as therapeutic drugs and vaccines have limited efficacy against drug-resistant serogroups of Vibrio cholerae. As such, new solutions that can treat cholera in an efficient manner that avoids Vibrio cholerae's adaptive immunity are needed. Nanoparticles (NPs) are a suitable platform for enhancing current theranostic tools because of their biocompatibility and ability to improve drug circulation and targeting. Nanoparticle surfaces can also be modified with various protein receptors targeting cholera toxins produced by Vibrio cholerae. This review will address recent developments in diagnostics, therapeutics, and prevention against cholera particularly focusing on the use of metal-based nanoparticles and organic nanoparticles. We will then discuss future directions regarding nanoparticle research for cholera.

Sodium Phytate-Incorporated Gelatin-Silicate Nanoplatelet Composites for Enhanced Cohesion and Hemostatic Function of Shear-Thinning Biomaterials

Shear-thinning biomaterials (STBs) based on gelatin-silicate nanoplatelets (SNs) are emerging as an alternative to conventional coiling and clipping techniques in the treatment of vascular anomalies. Improvements in the cohesion of STB hydrogels pave the way toward their translational application in minimally invasive therapies such as endovascular embolization repair. In the present study, sodium phytate (Phyt) additives are used to tune the electrostatic network of SNs-gelatin STBs, thereby promoting their mechanical integrity and facilitating injectability through standard catheters. We show that an optimized amount of Phyt enhances storage modulus by approximately one order of magnitude and reduces injection force by ≈58% without compromising biocompatibility and hydrogel wet stability. The Phyt additives are found to decrease the immune responses induced by SNs. In vitro embolization experiments suggest a significantly lower rate of failure in Phyt-incorporated STBs than in control groups. Furthermore, the addition of Phyt leads to accelerated blood coagulation (reduces clotting time by ≈45% compared to controls) due to the contributions of negatively charged phosphate groups, which aid in the prolonged durability of STB in coagulopathic patients. Therefore, the proposed approach is an effective method for the design of robust and injectable STBs for minimally invasive treatment of vascular malformations.

Visualizing subcellular rearrangements in intact β cells using soft x-ray tomography

Characterizing relationships between cell structures and functions requires mesoscale mapping of intact cells showing subcellular rearrangements following stimulation; however, current approaches are limited in this regard. Here, we report a unique application of soft x-ray tomography to generate three-dimensional reconstructions of whole pancreatic β cells at different time points following glucose-stimulated insulin secretion. Reconstructions following stimulation showed distinct insulin vesicle distribution patterns reflective of altered vesicle pool sizes as they travel through the secretory pathway. Our results show that glucose stimulation caused rapid changes in biochemical composition and/or density of insulin packing, increased mitochondrial volume, and closer proximity of insulin vesicles to mitochondria. Costimulation with exendin-4 (a glucagon-like peptide-1 receptor agonist) prolonged these effects and increased insulin packaging efficiency and vesicle maturation. This study provides unique perspectives on the coordinated structural reorganization and interactions of organelles that dictate cell responses.

Directional limits on persistent gravitational waves using LIGO S5 science data

The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2-20×10(-50)  strain(2) Hz(-1) and 5-35×10(-49)  strain(2) Hz(-1) sr(-1) for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW strain from interesting targets including Sco X-1, SN 1987A and the Galactic center as low as ≈7×10(-25) in the most sensitive frequency range near 160 Hz.

Targeted use of exoglycosidase digestion for the structural elucidation of neutral O-linked oligosaccharides

Exoglycosidase digestion in combination with the catalog-library approach (CLA) is used with matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) to obtain the complete structure of oligosaccharides. The CLA is a collision-induced dissociation (CID)-based method used to determine the structure of O-linked neutral oligosaccharides. It provides both linkage and stereochemical information. Exoglycosidases are used to confirm independently the validity of the CLA. In some cases, the CLA provides structural information on all but a single residue. Exoglycosidase is used to refine these structures. In this way, exoglycosidase use is targeted employing only a small number of enzymes. Exoglycosidase arrays, which have been used with N-linked oligosaccharides, is avoided despite the larger variations in structures of O-linked species.

Identification and structural elucidation of lectin-binding oligosaccharides by bioaffinity matrix-assisted laser desorption/ionization Fourier transform mass spectrometry

Cortical granule lectin (CGL) is released by the egg of the South African toad Xenopus laevis upon fertilization. The lectin binds to oligosaccharides in the extracellular matrix of the egg to form a physical block to prevent additional sperm penetration or polyspermy. To identify the oligosaccharides that bind to CGL, the lectin was immobilized on the surface of a matrix-assisted laser desorption/ionization probe. This bioaffinity probe was used to determine oligosaccharides that bind preferentially to CGL. Structural analyses based on collision-induced dissociation was used to determine that oligosaccharides with the sulfate esters at the nonreducing ends preferentially bind to the lectin.

Profiling with structural elucidation of the neutral and anionic O-linked oligosaccharides in the egg jelly coat of Xenopus laevis by Fourier transform mass spectrometry

A strategic method with high speed and sensitivity is outlined for the analysis of mucin-type oligosaccharide from the jelly coat of Xenopus laevis. The method relies primarily on mass spectrometric techniques, in this case matrix-assisted laser desorption/ionization Fourier-transform mass spectrometry (MALDI-FTMS) and collision-induced dissociation (CID). Separation with isolation of the oligosaccharides was streamlined to couple well with mass spectrometry allowing the rapid determination of all detectable components from both neutral and anionic species. Partial structures of anionic components, composed primarily of sulfate esters, were obtained with CID. For neutral species, a method that allowed the complete structural determination using mass spectrometry was used. The method builds on the structure of small number of known compounds to determine unknown structures from the same biological source. In this example, a small number of oligosaccharides, elucidated previously by NMR, were used to develop a set of substructural motifs that were characterized by CID. The presence of the motifs in the CID spectra were then used to determine the structures of unknown compounds that were in abundances too small for NMR analysis.

Electrophoresis Separation in Open Microchannels. A Method for Coupling Electrophoresis with MALDI-MS

The separation of biological mixtures in open micro-channels using electrophoresis with rapid and simple coupling to mass spectrometry is introduced. Rapid open-access channel electrophoresis employs microchannels that are manufactured on microchips. Separation is performed in the open channels, and the chips are transferred to a matrix-assisted laser desorption/ionization (MALDI) source after the solvent is evaporated. The matrix (2,5-dihydroxybenzoic acid) is placed in the solution with the run buffer before the separation of the analyte components. After separation, the solvent is evaporated and the microchip is ready for MALDI-MS analysis. The microchip is placed directly into a specially designed ion source of an external source Fourier transform mass spectrometry instrument. Separation of simple mixtures containing oligosaccharides and peptides is shown.

Catalog-library approach for the rapid and sensitive structural elucidation of oligosaccharides

We obtained the nearly complete structural elucidation of oligosaccharide components, including sequence, linkage, and even stereochemistry in the picomolar levels. The "catalog-library" approach is used for elucidating the structures of minor components in a mixture of oligosaccharides. Oligosaccharides released from a family of glycoproteins are often composed of a small finite set of monosaccharides. In this regard, the numerous oligosaccharide species are analogous to the products found in syntheses involving combinatorial libraries. The great structural diversity in the library is the result of the nearly infinite combinations in which even a small number of monosaccharides can be arranged. Fortunately, structural similarities exist between different oligosaccharides, as specific substructural motifs are preserved among different compounds. We propose that a catalog of substructural motifs can be identified and characterized by collision-induced dissociation mass spectrometry. The catalog is constructed from a set of known compounds that have been fully structurally elucidated by, for example, nuclear magnetic resonance. The catalog consists of the characteristic fragmentation patterns belonging to a set of specific substructural motifs. Collision-induced dissociation is used to determine the presence of these motifs and reconstruct the structures of less abundant components.

A general method for producing bioaffinity MALDI probes

A bioaffinity probe based on the idea of immobilizing avidin on the probe surface to extract biotinylated oligosaccharide is described. The probe is produced by taking advantage of the natural affinity of proteins for hydrophobic polymer films. The avidin is immobilized by simply drying the solution on a polymer film surface. This produces a bioaffinity probe that shows enhanced activity for biotin-labeled oligosaccharides. The probe is produced in a matter of minutes but is highly effective for concentrating biotinylated oligosaccharide on the surface. The best matrix for the analysis is DHB, and the best film for the probe is a polyester material commonly used for transparency film. The efficacy of the probe is illustrated with neutral and anionic oligosaccharides. Oligosaccharides derivatized with biotin are retained while those that are unlabeled are washed away. No trace of the unlabeled oligosaccharide is observed in the mass spectrum.

Characterization of neutral oligosaccharide-alditols from Xenopus laevis egg jelly coats by matrix-assisted laser desorption Fourier transform mass spectrometry

Neutral oligosaccharides were released by alkaline sodium borohydride reduction of the jelly coating from the South African clawed toad, Xenopus laevis. The oligosaccharides were isolated by HPLC and analyzed by matrix-assisted laser desorption ionization (MALDI)-Fourier transform mass spectrometry (FTMS). The mass spectrometry analysis allowed confirmation of 12 structures first proposed by Strecker et al. using nuclear magnetic resonance. In addition, seven new oligosaccharides with weak abundances were found and characterized by mass spectrometry. A method for discriminating metastable fragments from quasimolecular ions is described. It involves doping the sample with cesium chloride. Cesium-coordinated oligosaccharides do not fragment as readily as those coordinated to sodium. Tandem MS experiments are performed on an unknown oligosaccharide illustrating the potential of MALDI-collision-induced dissociation-FTMS.

Turning behavior induced by injections of glutamate receptor antagonists into the substantia nigra of the rat

We have found recently that muscimol microinjections into the subthalamic nucleus produce contralateral turning activity [Murer and Pazo (1993) NeuroReport, 4:1219-1222]. To test the hypothesis that a reduced glutamate action on substantia nigra pars reticulata neurons mediates this turning response, we examined the effect of unilateral intranigral microinjections of the AMPA/kainate receptor antagonist 6,7-dinitro-quinoxaline-2,3-dione (DNQX) and the competitive N-methyl-D-aspartate (NMDA) receptor antagonist DL-2-amino-5-phosphonovaleric acid (AP-5). DNQX and AP-5 both produced a dose-dependent contralateral turning response, while vehicle administration did not induce turning activity. Application of glutamate receptor antagonists at adjacent regions of the mesencephalic tegmentum were also ineffective. Coadministration of NMDA or AMPA significantly reduced the turning response induced by AP-5 or DNQX, respectively. Lesions of the nigrostriatal pathway by 6-hydroxydopamine did not modify the response to DNQX or AP-5 administration into the nigra. However, their behavioral effects were significantly reduced by a lesion of the ipsilateral subthalamic nucleus. Our results show that the blockade of a tonic input acting on AMPA/kainate and NMDA receptors located at the substantia nigra produces contralateral turning behavior. The effect seems to involve pars reticulata cells since this area remains unchanged after destruction of dopaminergic neurons. The subthalamic nucleus seems to be the endogenous source of the agonist acting on the nigral glutamate receptors related to turning behavior.

Effects of base substituents on the hydration of B- and Z-DNA: correlations to the B- to Z-DNA transition

We present a study of how substituent groups of naturally occurring and modified nucleotide bases affect the degree of hydration of right-handed B-DNA and left-handed Z-DNA. A comparison of poly(dG-dC) and poly(dG-dm5C) titrations with the lipotropic salts of the Hofmeister series infers that the methyl stabilization of cytosines as Z-DNA is primarily a hydrophobic effect. The hydration free energies of various alternating pyrimidine-purine sequences in the two DNA conformations were calculated as solvent free energies from solvent accessible surfaces. Our analysis focused on the N2 amino group of purine bases that sits in the minor groove of the double helix. Removing this amino group from guanine to form inosine (I) destabilizes Z-DNA, while adding this group to adenines to form 2-aminoadenine (A') stabilizes Z-DNA. These predictions were tested by comparing the salt concentrations required to crystallize hexanucleotide sequences that incorporate d(CG), d(CI), d(TA) and d(TA') base pairs as Z-DNA. Combining the current results with our previous analysis of major groove substituents, we derived a thermodynamic cycle that relates the systematic addition, deletion, or substitution of each base substituent to the B- to Z-DNA transition free energy.

Estrogen metabolism in primary kidney cell cultures from Syrian hamsters

Estrogen metabolism was evaluated in freshly isolated kidney and liver microsomes and in primary kidney cell cultures from Syrian hamsters, a potential experimental model for examining the possible role(s) of estrogens in tumor initiation and development. Initial velocity studies of the conversion of estradiol to 2-hydroxyestradiol, as determined by the 3H2O release assay with the substrate [2-3H]estradiol, resulted in similar apparent Kms of estrogen 2-hydroxylase of 2.85 and 6.25 microM for liver and renal microsomes, respectively. The apparent Vmax for freshly prepared liver microsomes was 0.13 nmol.mg-1.min-1, while that for renal microsomes was 0.040 nmol.mg-1.min-1. Evaluation of estrogen metabolism was also performed in primary cell cultures of hamster kidney cells, consisting of 75% epithelial cells. [6,7-3H]Estradiol (10 microM) was incubated for 0, 24 and 48 h in primary kidney cell cultures, and the organic soluble metabolites analyzed by reverse-phase HPLC. The cultures from untreated, castrated hamsters metabolize [3H]estradiol to yield small quantities of estrone and significant amounts of polar metabolites, while no catechol estrogens were isolated. Estrogen metabolism by diethylstilbestrol-treated (DES-treated) hamster kidney cell cultures also provided small quantities of estrone and no evidence of catechol estrogens. Additionally, larger amounts of additional polar metabolites were isolated in the cultures from DES-treated hamsters. Finally, levels of estrogen 2-hydroxylase were detected in these cultures using the 3H2O release assay. Thus, the short-term primary kidney cell cultures from the Syrian hamster are capable of metabolizing estrogens. Furthermore, the enzymatic processes appear to be available for the conversion of any catechol estrogens formed into more polar metabolites. These investigations in intact cells, capable of performing all biochemical processes, complement both in vivo and subcellular biochemical studies and may aid in elucidating the roles of estrogens and estrogen metabolism in the initiation and development of estrogen-induced, estrogen-dependent kidney tumors in the Syrian hamster.

Significance of hepatic triglyceride lipase activity in the regulation of serum high density lipoproteins in type II diabetes mellitus

We investigated the regulation of serum high density lipoprotein (HDL) cholesterol metabolism in patients with type II diabetes mellitus by determining the activities of the two lipolytic enzymes that play major roles in the production and degradation of HDL. The activity of lipoprotein lipase (LPL), the enzyme responsible for HDL cholesterol production, and the activity of hepatic triglyceride lipase (HTGL), the enzyme that facilitates the catabolism of HDL, were measured in plasma obtained after iv injection of heparin. Thirty patients were selected to represent a wide range of serum HDL cholesterol concentrations (low, normal, and high HDL cholesterol groups). Mean lipoprotein lipase activity was similar in all three groups [122 +/- 10 (SEM) U/mL in the low HDL, 141 +/- 11 U/mL in the normal HDL, and 148 +/- 30 U/mL in the high HDL group]. Mean HTGL activity was markedly decreased in the high HDL group; the mean values were 346 +/- 28 U/mL in the low HDL, 320 +/- 25 U/mL in the normal HDL, and 191 +/- 23 U/mL in the high HDL groups, respectively. Body weight and insulin requirement correlated directly with HTGL activity and inversely with serum HDL cholesterol levels. These findings suggest that in type II diabetes mellitus low serum HDL cholesterol levels may be due to an increased rate of clearance by HTGL.