Engineered matrices reveal stiffness-mediated chemoresistance in patient-derived pancreatic cancer organoids.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by its fibrotic and stiff extracellular matrix. However, how the altered cell/extracellular-matrix signalling contributes to the PDAC tumour phenotype has been difficult to dissect. Here we design and engineer matrices that recapitulate the key hallmarks of the PDAC tumour extracellular matrix to address this knowledge gap. We show that patient-derived PDAC organoids from three patients develop resistance to several clinically relevant chemotherapies when cultured within high-stiffness matrices mechanically matched to in vivo tumours. Using genetic barcoding, we find that while matrix-specific clonal selection occurs, cellular heterogeneity is not the main driver of chemoresistance. Instead, matrix-induced chemoresistance occurs within a stiff environment due to the increased expression of drug efflux transporters mediated by CD44 receptor interactions with hyaluronan. Moreover, PDAC chemoresistance is reversible following transfer from high- to low-stiffness matrices, suggesting that targeting the fibrotic extracellular matrix may sensitize chemoresistant tumours. Overall, our findings support the potential of engineered matrices and patient-derived organoids for elucidating extracellular matrix contributions to human disease pathophysiology.

Benchmarking a universal smoking machine adaptor for tobacco product testing.

SIGNIFICANCE: Characterisation of tobacco product emissions is an important step in assessing their impact on public health. Accurate and repeatable emissions data require that a leak-tight seal be made between the smoking or vaping machine and the mouth-end of the tobacco product being tested. This requirement is challenging because of the variety of tobacco product mouth-end geometries being puffed on by consumers today. We developed and tested a prototype universal smoking machine adaptor (USMA) that interfaces with existing machines and reliably seals with a variety of tobacco product masses and geometries. METHODS: Emissions were machine-generated using the USMA and other available adaptors for a variety of electronic cigarettes (n=7 brands), cigars (n=4), cigarillos (n=2), a heated tobacco product, and a reference cigarette (1R6F), and mainstream total particulate matter (TPM) and nicotine were quantified. Data variability (precision, n≥10 replicates/brand) for all products and error (accuracy) from certified values (1R6F) were compared across adaptors. RESULTS: TPM and nicotine emissions generated using the USMA were accurate, precise and agreed with certified values for the 1R6F reference cigarette. Replicate data indicate that USMA repeatability across all tobacco products tested generally meets or exceeds that from the comparison adaptors and extant data. CONCLUSION: The USMA seals well with a variety of combustible tobacco products, e-cigarettes with differing geometries and plastic-tipped cigarillos. Variability for all measures was similar or smaller for the USMA compared with other adaptors.

Universal smoking machine adaptor for tobacco product testing.

SIGNIFICANCE: Historically, tobacco product emissions testing using smoking machines has largely focused on combustible products, such as cigarettes and cigars. However, the popularity of newer products, such as electronic cigarettes (e-cigarettes), has complicated emissions testing because the products' mouth-end geometries do not readily seal with existing smoking and vaping machines. The demand for emissions data on popularly used products has led to inefficient and non-standardised solutions, such as laboratories making their geometry-specific custom adaptors and/or employing flexible tubing, for each unique mouth-end geometry tested. A user-friendly, validated, universal smoking machine adaptor (USMA) is needed for testing the variety of tobacco products reflecting consumer use, including e-cigarettes, heated tobacco products, cigarettes, plastic-tipped cigarillos and cigars. METHODS: A prototype USMA that is compatible with existing smoking/vaping machines was designed and fabricated. The quality of the seal between the USMA and different tobacco products, including e-cigarettes, cigars and cigarillos, was evaluated by examining the leak rate. RESULTS: Unlike commercial, product-specific adaptors, the USMA seals well with a wide range of tobacco product mouth-end geometries and masses. This includes e-cigarettes with non-cylindrical mouth ends and cigarillos with cuboid-like plastic tips. USMA leak rates were lower than or equivalent to commercial, product-specific adaptors. CONCLUSION: This report provides initial evidence that the USMA seals reliably with a variety of tobacco product mouth-end geometries and can be used with existing linear smoking/vaping machines to potentially improve the precision, repeatability and reproducibility of machine smoke yield data. Accurate and reproducible emissions testing is critical for regulating tobacco products.

Challenges in the Transition from Acute Hospital Care to Home for Spanish-Speaking Latino Patients with TBI and Families: Perspectives of Healthcare Providers and Interpreters.

Language-based disparities negatively impact patient outcomes. Spanish-speaking Latino patients with traumatic brain injury (TBI) transitioning home from acute hospital care and their families have poor TBI-related outcomes; further, they have significant difficulties navigating the healthcare system due to care fragmentation and limited provider support. These challenges are exacerbated by language barriers. There are disproportionately fewer bilingual providers and interpreters in the U.S. healthcare system for patients with TBI for whom English is not their primary language. Although Spanish-speaking Latino patients with TBI and their families communicate with healthcare providers using interpreters on a regular basis, limited research has explored the healthcare delivery perspective. The purpose of this study was to understand the perspectives of healthcare providers and interpreters regarding their experience caring for or supporting Spanish-speaking Latino patients with TBI and their families during the transition home from acute hospital care. This qualitative descriptive study included 10 bilingual (English and Spanish-speaking) participants: 7 interdisciplinary providers and 3 interpreters; findings were analyzed using rapid qualitative analysis to inform intervention adaptation. Four themes were identified: 1) language misalignment decreases health literacy and increases length of stay; 2) TBI-related cognitive impairments, coupled with language differences, make communication challenging; 3) unique social contributors to health directly decrease health equity; and 4) recommendations to improve access and justice in transitional care. There are multiple opportunities to improve transitional care support provided to Spanish-speaking Latino patients with TBI and their families in a manner that is not currently being addressed in research or in practice.

Strategies for Effective Dentist-Patient Communication: A Literature Review.

The effectiveness of high-quality dental care predominantly lies on the communication between dentist and patient. However, little literature has reported the importance of these "soft skills" in dental practice. The aim of this literature review is to explore strategies for effective dentist-patient communication. Dentist-patient communication is a bidirectional process involving the exchange of ideas that should be clear (easy to understand), correct (accurate), concise (to the point), complete (with essential information), and cohesive (well-organized). Effective communication empowers patients with the knowledge required to make an informed decision about their own oral health. It not only improves the dentist's efficiency and boosts patient confidence, but also alleviates patients' dental anxiety and fear, addresses patients' needs and preferences, increases patients' adherence, and enhances patient satisfaction. To enhance dentist-patient communication, dentists should take the patient-centered approach as a premise. The approach comprises understanding patients' illnesses, shared decision-making, and mindful intervention at the patient's own pace. In addition, dentists should use simple, succinct language, proper body posture, gestures, facial expressions, and eye contact when interacting with patients. Dentists should show empathy, encourage questions and feedback, employ visual aids, and give ample time to patients. Nowadays, dentists and their patients use messaging applications in their communication. This form of telecommunication is not only a convenient way of communication but also reduces the costs associated with a dentist visit. In conclusion, effective dentist-patient communication is vital for the success of dental practice. Dentists who prioritize communication and build positive relationships with their patients are more likely to achieve positive outcomes and foster the expansion of their dental practice.

Laminin-associated integrins mediate Diffuse Intrinsic Pontine Glioma infiltration and therapy response within a neural assembloid model.

Diffuse Intrinsic Pontine Glioma (DIPG) is a highly aggressive and fatal pediatric brain cancer. One pre-requisite for tumor cells to infiltrate is adhesion to extracellular matrix (ECM) components. However, it remains largely unknown which ECM proteins are critical in enabling DIPG adhesion and migration and which integrin receptors mediate these processes. Here, we identify laminin as a key ECM protein that supports robust DIPG cell adhesion and migration. To study DIPG infiltration, we developed a DIPG-neural assembloid model, which is composed of a DIPG spheroid fused to a human induced pluripotent stem cell-derived neural organoid. Using this assembloid model, we demonstrate that knockdown of laminin-associated integrins significantly impedes DIPG infiltration. Moreover, laminin-associated integrin knockdown improves DIPG response to radiation and HDAC inhibitor treatment within the DIPG-neural assembloids. These findings reveal the critical role of laminin-associated integrins in mediating DIPG progression and drug response. The results also provide evidence that disrupting integrin receptors may offer a novel therapeutic strategy to enhance DIPG treatment outcomes. Finally, these results establish DIPG-neural assembloid models as a powerful tool to study DIPG disease progression and enable drug discovery.

Constitutive knockout of interleukin-6 ameliorates memory deficits and entorhinal astrocytosis in the MRL/lpr mouse model of neuropsychiatric lupus.

BACKGROUND: Neuropsychiatric lupus (NPSLE) describes the cognitive, memory, and affective emotional burdens faced by many lupus patients. While NPSLE's pathogenesis has not been fully elucidated, clinical imaging studies and cerebrospinal fluid (CSF) findings, namely elevated interleukin-6 (IL-6) levels, point to ongoing neuroinflammation in affected patients. Not only linked to systemic autoimmunity, IL-6 can also activate neurotoxic glial cells the brain. A prior pre-clinical study demonstrated that IL-6 can acutely induce a loss of sucrose preference; the present study sought to assess the necessity of chronic IL-6 exposure in the NPSLE-like disease of MRL/lpr lupus mice. METHODS: We quantified 1308 proteins in individual serum or pooled CSF samples from MRL/lpr and control MRL/mpj mice using protein microarrays. Serum IL-6 levels were plotted against characteristic NPSLE neurobehavioral deficits. Next, IL-6 knockout MRL/lpr (IL-6 KO; n = 15) and IL-6 wildtype MRL/lpr mice (IL-6 WT; n = 15) underwent behavioral testing, focusing on murine correlates of learning and memory deficits, depression, and anxiety. Using qPCR, we quantified the expression of inflammatory genes in the cortex and hippocampus of MRL/lpr IL-6 KO and WT mice. Immunofluorescent staining was performed to quantify numbers of microglia (Iba1 +) and astrocytes (GFAP +) in multiple cortical regions, the hippocampus, and the amygdala. RESULTS: MRL/lpr CSF analyses revealed increases in IL-17, MCP-1, TNF-α, and IL-6 (a priori p-value < 0.1). Serum levels of IL-6 correlated with learning and memory performance (R2 = 0.58; p = 0.03), but not motivated behavior, in MRL/lpr mice. Compared to MRL/lpr IL-6 WT, IL-6 KO mice exhibited improved novelty preference on object placement (45.4% vs 60.2%, p < 0.0001) and object recognition (48.9% vs 67.9%, p = 0.002) but equivalent performance in tests for anxiety-like disease and depression-like behavior. IL-6 KO mice displayed decreased cortical expression of aif1 (microglia; p = 0.049) and gfap (astrocytes; p = 0.044). Correspondingly, IL-6 KO mice exhibited decreased density of GFAP + cells compared to IL-6 WT in the entorhinal cortex (89 vs 148 cells/mm2, p = 0.037), an area vital to memory. CONCLUSIONS: The inflammatory composition of MRL/lpr CSF resembles that of human NPSLE patients. Increased in the CNS, IL-6 is necessary to the development of learning and memory deficits in the MRL/lpr model of NPSLE. Furthermore, the stimulation of entorhinal astrocytosis appears to be a key mechanism by which IL-6 promotes these behavioral deficits.

Interplay of the Tfb1 pleckstrin homology domain with Rad2 and Rad4 in transcription coupled and global genomic nucleotide excision repair.

Transcription-coupled repair (TCR) and global genomic repair (GGR) are two subpathways of nucleotide excision repair (NER). The TFIIH subunit Tfb1 contains a Pleckstrin homology domain (PHD), which was shown to interact with one PHD-binding segment (PB) of Rad4 and two PHD-binding segments (PB1 and PB2) of Rad2 in vitro. Whether and how the different Rad2 and Rad4 PBs interact with the same Tfb1 PHD, and whether and how they affect TCR and GGR within the cell remain mysterious. We found that Rad4 PB constitutively interacts with Tfb1 PHD, and the two proteins may function within one module for damage recognition in TCR and GGR. Rad2 PB1 protects Tfb1 from degradation and interacts with Tfb1 PHD at a basal level, presumably within transcription preinitiation complexes when NER is inactive. During a late step of NER, the interaction between Rad2 PB1 and Tfb1 PHD augments, enabling efficient TCR and GGR. Rather than interacting with Tfb1 PHD, Rad2 PB2 constrains the basal interaction between Rad2 PB1 and Tfb1 PHD, thereby weakening the protection of Tfb1 from degradation and enabling rapid augmentation of their interactions within TCR and GGR complexes. Our results shed new light on NER mechanisms.

SMARCB1 (INI1)-deficient sinonasal carcinoma manifesting as oral lesions: A report of two cases.

BACKGROUND: Sinonasal carcinomas represent a rare group of malignancies, accounting for less than 5% of all head and neck cancers and a worldwide incidence of less than 1 case per 100 000 inhabitants annually. Despite the restricted anatomical location, sinonasal carcinomas harbor some of the most histologically and molecularly diverse groups of tumors. SMARCB1 (INI1)-deficient sinonasal carcinomas are locally aggressive tumors commonly detected late, leading to devastating morbidity and mortality. CASE REPORT: We present two cases of SMARCB1-deficient sinonasal carcinoma involving the oral cavity and presenting as progressive radiolucent lesions with local swelling associated with maxillary dentition and alveolar bone. Both cases were initially considered odontogenic in origin and involved the destruction of the left anterior maxilla. CONCLUSION: Given the rarity and the variable presentation of these tumors, they pose a challenge for head and neck surgeons, dentists, and pathologists due to the potential overlapping features with odontogenic and non-odontogenic inflammatory and neoplastic lesions. These cases highlight the importance of a multidisciplinary team and include SMARCB1-deficient sinonasal carcinomas in the differential diagnosis of destructive lesions of the maxilla.

Evaluation of video-assisted HPV education in government-supported clinics in Western Kenya.

Despite prevalent preventative methods of human papillomavirus (HPV), cervical cancer remains the foremost cause of cancer-related death among women of reproductive age in Western Kenya. HPV self-sampling is a preventative measure that can improve accessibility and availability to cervical cancer screening. Correct education about HPV is crucial to combating stigma and increasing HPV screening uptake. In this study, we evaluated the workflow impact of a video-assisted HPV education to promote self-sampling in clinical settings in Kisumu, Kenya. We conducted a descriptive workflow study nested in a two-part cluster-randomized control trial in six government-supported health clinics in Kisumu County. We observed the workflow of HPV screening video-assisted and standard health educations. and evaluated community and clinic health assistant facilitation (CCHA), duration, and feasibility of the intervention. Thirty HPV screening-eligible women who participated in the video intervention were recruited for three focus group discussions (FGDs). The FGDs aimed to better understand women's experience with the video screening, their impressions on the content, and feedback about intervention logistics. Across 33 observations, 16.5 women per day watched the educational video at intervention clinics, and 14 women per day heard standard Ministry of Health cervical cancer prevention education talks at control clinics. Sixty-three percent of women participated in HPV self-sampling in the intervention sites, compared to forty-six percent who screened after standard health talks at control sites. The workflow observations identified variable video projection and viewing space, access to power supply, and CCHA availability and ability to utilize the projector as major factors impacting education workflow. Women in FGDs appreciated the video modality, length of video, and education location. HPV video education is a suitable intervention, with further research recommended to determine the viability of sustainably implementing the intervention in a clinic environment. This research is fully funded by the Duke University Global Health Institute.

A Library of Elastin-like Proteins with Tunable Matrix Ligands for In Vitro 3D Neural Cell Culture.

Hydrogels with encapsulated cells have widespread biomedical applications, both as tissue-mimetic 3D cultures in vitro and as tissue-engineered therapies in vivo. Within these hydrogels, the presentation of cell-instructive extracellular matrix (ECM)-derived ligands and matrix stiffness are critical factors known to influence numerous cell behaviors. While individual ECM biopolymers can be blended together to alter the presentation of cell-instructive ligands, this typically results in hydrogels with a range of mechanical properties. Synthetic systems that allow for the facile incorporation and modulation of multiple ligands without modification of matrix mechanics are highly desirable. In the present work, we leverage protein engineering to design a family of xeno-free hydrogels (i.e., devoid of animal-derived components) consisting of recombinant hyaluronan and recombinant elastin-like proteins (ELPs), cross-linked together with dynamic covalent bonds. The ELP components incorporate cell-instructive peptide ligands derived from ECM proteins, including fibronectin (RGD), laminin (IKVAV and YIGSR), collagen (DGEA), and tenascin-C (PLAEIDGIELTY and VFDNFVL). By carefully designing the protein primary sequence, we form 3D hydrogels with defined and tunable concentrations of cell-instructive ligands that have similar matrix mechanics. Utilizing this system, we demonstrate that neurite outgrowth from encapsulated embryonic dorsal root ganglion (DRG) cultures is significantly modified by cell-instructive ligand content. Thus, this library of protein-engineered hydrogels is a cell-compatible system to systematically study cell responses to matrix-derived ligands.

Cell Microencapsulation Within Engineered Hyaluronan Elastin-Like Protein (HELP) Hydrogels.

Three-dimensional cell encapsulation has rendered itself a staple in the tissue engineering field. Using recombinantly engineered, biopolymer-based hydrogels to encapsulate cells is especially promising due to the enhanced control and tunability it affords. Here, we describe in detail the synthesis of our hyaluronan (i.e., hyaluronic acid) and elastin-like protein (HELP) hydrogel system. In addition to validating the efficacy of our synthetic process, we also demonstrate the modularity of the HELP system. Finally, we show that cells can be encapsulated within HELP gels over a range of stiffnesses, exhibit strong viability, and respond to stiffness cues. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Elastin-like protein modification with hydrazine Basic Protocol 2: Nuclear magnetic resonance quantification of elastin-like protein modification with hydrazine Basic Protocol 3: Hyaluronic acid-benzaldehyde synthesis Basic Protocol 4: Nuclear magnetic resonance quantification of hyaluronic acid-benzaldehyde Basic Protocol 5: 3D cell encapsulation in hyaluronan elastin-like protein gels.

Tunable hydrogel viscoelasticity modulates human neural maturation.

Human-induced pluripotent stem cells (hiPSCs) have emerged as a promising in vitro model system for studying neurodevelopment. However, current models remain limited in their ability to incorporate tunable biomechanical signaling cues imparted by the extracellular matrix (ECM). The native brain ECM is viscoelastic and stress-relaxing, exhibiting a time-dependent response to an applied force. To recapitulate the remodelability of the neural ECM, we developed a family of protein-engineered hydrogels that exhibit tunable stress relaxation rates. hiPSC-derived neural progenitor cells (NPCs) encapsulated within these gels underwent relaxation rate-dependent maturation. Specifically, NPCs within hydrogels with faster stress relaxation rates extended longer, more complex neuritic projections, exhibited decreased metabolic activity, and expressed higher levels of genes associated with neural maturation. By inhibiting actin polymerization, we observed decreased neuritic projections and a concomitant decrease in neural maturation gene expression. Together, these results suggest that microenvironmental viscoelasticity is sufficient to bias human NPC maturation.

Effects of captions on viewers' perceptions of images depicting human-primate interaction.

Promoting human contact with wildlife can be harmful to animal conservation and welfare by exposing animals to unsafe situations and driving demand for wildlife tourism and exotic pets. Conservationists and researchers justifiably use social media to raise awareness, but professionals posting pictures of themselves with animals can have unintended negative consequences for conservation. Though the International Union for Conservation of Nature Best Practice Guidelines for Responsible Images of Non-Human Primates suggests researchers and animal professionals provide context in captions of images of humans interacting with primates, there is little research investigating whether this approach is effective. We investigated whether informative captions affect viewers' desires to have primates as pets and attitudes toward wildlife conservation. Using 4 mock Instagram posts depicting human-gorilla and human-slender loris interactions, we surveyed 2977 respondents to assess the effect of captions on viewers' perceptions of the images and primate conservation. Likert scale response data were analyzed with ordered probit regression models. Captions clearly contextualizing an image as research resulted in a significantly higher agreement that posts depicted wildlife research (gorilla ß = 0.28 [SE 0.06], p < 0.001; loris ß = 0.18 [0.06], p = 0.002), but such captions resulted in no significant difference in responses regarding viewers' desires to own primates as pets or questions regarding the primates' conservation statuses. Although most participants agreed the primates were endangered, more than 56% and 59%, respectively, stated they would have a gorilla or loris as a pet, that they would make good pets, or both, further supporting the conclusion that captions do not minimize harmful impacts of images of human-primate interactions.

Efectos de los pies de foto sobre la percepción del público de imágenes de la interacción humano-primate Resumen La promoción del contacto humano con la fauna puede ser dañina para la conservación y el bienestar animal al exponer a la fauna a situaciones poco seguras e incrementar la demanda por el turismo de fauna y las mascotas exóticas. Los conservacionistas y los investigadores usan con justificación las redes sociales para generar conciencia, pero los profesionales que publican imágenes de sí mismos con los animales pueden generar sin intención consecuencias negativas para la conservación. Aunque la Guía de Buenas Prácticas de la Unión Internacional para la Conservación de la Naturaleza para la Obtención Responsable de Imágenes de Primates No Humanos sugiere que los investigadores y profesionales de fauna proporcionen contexto en los pies de foto de las imágenes de humanos interactuando con primates, hay muy poca investigación sobre si esta estrategia es efectiva. Investigamos si los pies de foto informativos afectan el deseo del público de tener primates como mascotas y la actitud hacia la conservación de la fauna. Usamos cuatro publicaciones simuladas de Instagram representando interacciones humano-gorila y humano-loris para encuestar a 2,977 respondientes y estudiar el efecto de los pies de foto sobre la percepción del público de las imágenes y la conservación de primates. Analizamos los datos de respuesta de escala Likert con modelos de regresión probit ordenada. Los pies de foto que contextualizaban con claridad una imagen como trabajo de investigación resultaron en mayor aceptación de que las publicaciones representaban investigación sobre la fauna (gorila ß = 0.28 [SE 0.06], p < 0.001; loris ß = 0.18 [0.06], p = 0.002), pero dichos textos resultaron en una diferencia no significativa en las respuestas con respecto al deseo del público de tener primates como mascota o preguntas sobre el estado de conservación de los primates. Mientras que la mayoría de los participantes estuvo de acuerdo en que los primates están en peligro de extinción, más del 56% y 59%, respectivamente, afirmaron que tendrían un gorila o un loris como mascota, que serían buenas mascotas, o ambas. Esto suma a la conclusión de que los pies de foto no minimizan el impacto dañino de las imágenes de interacciones humano-primate.

Spatially controlled construction of assembloids using bioprinting.

The biofabrication of three-dimensional (3D) tissues that recapitulate organ-specific architecture and function would benefit from temporal and spatial control of cell-cell interactions. Bioprinting, while potentially capable of achieving such control, is poorly suited to organoids with conserved cytoarchitectures that are susceptible to plastic deformation. Here, we develop a platform, termed Spatially Patterned Organoid Transfer (SPOT), consisting of an iron-oxide nanoparticle laden hydrogel and magnetized 3D printer to enable the controlled lifting, transport, and deposition of organoids. We identify cellulose nanofibers as both an ideal biomaterial for encasing organoids with magnetic nanoparticles and a shear-thinning, self-healing support hydrogel for maintaining the spatial positioning of organoids to facilitate the generation of assembloids. We leverage SPOT to create precisely arranged assembloids composed of human pluripotent stem cell-derived neural organoids and patient-derived glioma organoids. In doing so, we demonstrate the potential for the SPOT platform to construct assembloids which recapitulate key developmental processes and disease etiologies.

"If you respect me, you are respecting my culture": methods and recommendations for personalizing a TBI transitional care intervention.

OBJECTIVE: Despite research, national legislation, and clinical guidelines supporting transitional care, there is minimal benefit from existing transitional care interventions for racial/ethnic minorities with traumatic brain injury (TBI) discharged home from acute hospital care. Existing TBI transitional care interventions are not tailored to address the needs/preferences of patients from various racial/ethnic minority groups. The purpose of this study was to describe use of personalization to tailor a TBI transitional care intervention for various racial/ethnic groups. DESIGN: Following preliminary intervention manual development, a qualitative descriptive study was conducted using eight focus groups with 40 English-and Spanish-speaking participants (12 patients, 12 caregivers, and 16 providers). RESULTS: Three personalization-related themes emerged: 1) what is important to me, 2) finding someone to deliver the intervention who can adapt to my needs, and 3) respect over culture. Findings informed personalization strategies within our final manual. CONCLUSIONS: We recommend researchers who wish to use personalization to tailor interventions to consider: 1) allowing stakeholders to dictate what is most important and 2) implementing an iterative intervention development process with input from diverse stakeholders. Findings have implications for informing the development of transitional care interventions to increase the likelihood that interventions are inclusive of needs and preferences of various races/ethnicities.

Elastin-like protein hydrogels with controllable stress relaxation rate and stiffness modulate endothelial cell function.

Mechanical cues from the extracellular matrix (ECM) regulate vascular endothelial cell (EC) morphology and function. Since naturally derived ECMs are viscoelastic, cells respond to viscoelastic matrices that exhibit stress relaxation, in which a cell-applied force results in matrix remodeling. To decouple the effects of stress relaxation rate from substrate stiffness on EC behavior, we engineered elastin-like protein (ELP) hydrogels in which dynamic covalent chemistry (DCC) was used to crosslink hydrazine-modified ELP (ELP-HYD) and aldehyde/benzaldehyde-modified polyethylene glycol (PEG-ALD/PEG-BZA). The reversible DCC crosslinks in ELP-PEG hydrogels create a matrix with independently tunable stiffness and stress relaxation rate. By formulating fast-relaxing or slow-relaxing hydrogels with a range of stiffness (500-3300 Pa), we examined the effect of these mechanical properties on EC spreading, proliferation, vascular sprouting, and vascularization. The results show that both stress relaxation rate and stiffness modulate endothelial spreading on two-dimensional substrates, on which ECs exhibited greater cell spreading on fast-relaxing hydrogels up through 3 days, compared with slow-relaxing hydrogels at the same stiffness. In three-dimensional hydrogels encapsulating ECs and fibroblasts in coculture, the fast-relaxing, low-stiffness hydrogels produced the widest vascular sprouts, a measure of vessel maturity. This finding was validated in a murine subcutaneous implantation model, in which the fast-relaxing, low-stiffness hydrogel produced significantly more vascularization compared with the slow-relaxing, low-stiffness hydrogel. Together, these results suggest that both stress relaxation rate and stiffness modulate endothelial behavior, and that the fast-relaxing, low-stiffness hydrogels supported the highest capillary density in vivo.

Mobility mediates maturation: Synthetic substrates to enhance neural differentiation.

The maturation of human induced pluripotent stem cell (hiPSC)-derived neurons in 2D is dependent upon cell attachment, spreading, and pathfinding across a biomaterial substrate. In this issue of Cell Stem Cell, Álvarez et al.1 demonstrate that highly mobile supramolecular scaffolds facilitate long-term hiPSC-derived motor neuron culture, increase maturation-related phenotypes, and recapitulate disease-relevant pathologies.

Electromechanical Cornea Reshaping for Refractive Vision Therapy.

The corneal stroma consists of orthogonally stacked collagen-fibril lamellae that determine the shape of the cornea and provide most of the refractive power of the eye. We have applied electromechanical reshaping (EMR), an electrochemical platform for remodeling cartilage and other semirigid tissues, to change the curvature of the cornea as a potential procedure for nonsurgical vision correction. EMR relies on short electrochemical pulses to electrolyze water, with subsequent diffusion of protons into the extracellular matrix of collagenous tissues; protonation of immobilized anions within this matrix disrupts the ionic-bonding network, leaving the tissue transiently responsive to mechanical remodeling. Re-equilibration to physiological pH restores the ionic matrix, resulting in persistent shape change of the tissue. Using ex vivo rabbit eyes, we demonstrate here the controlled change of corneal curvature over a wide range of refractive powers with no loss of optical transparency. Optical coherence tomography (OCT), combined with second-harmonic generation (SHG) and confocal microscopy, establish that EMR enables extremely fine control of corneal contouring while maintaining the underlying macromolecular collagen structure and stromal cellular viability, positioning electrochemical vision therapy as a potentially simple and ultralow-cost modality for correcting routine refractive errors.

Use of MEDEVAC Resources in Austere Settings: Paget-Schroetter in the Deployed Environment.

Medical evacuation (MEDEVAC) from a combat zone requires complex decision-making and coordination of assets. A MEDEVAC helicopter team transports not only battle-injured patients but also patients with urgent non-battle-related medical diagnoses from extremely remote locations and are at the mercy of terrain, weather, and enemy contact. The military represents a young population particularly susceptible to venous thoracic outlet syndrome (vTOS) given the rigorous physical activity demands. Current literature supports immediate anticoagulation and surgical decompression within 14 days of diagnosis of vTOS to prevent long-term morbidity. Presented is a case of service member with vTOS presenting at an extremely remote military clinic who underwent a prompt evacuation ∼7,000 miles utilizing rotary-wing transport, followed by three to four more fixed-wing flights to a military treatment facility in the United States. Immediate recognition and ultrasound of this patient to confirm vTOS upon presentation and effective communication to non-medical military commanders and the receiving medical personnel at each Echelon was necessary to ensure an expedited evacuation. The surgeons treating this patient recommend prompt evacuation of deployed service members with suspected vTOS, venogram at the Role 3 if ultrasound is inconclusive, anticoagulation, and return to a Role 4 CONUS facility for definitive surgical management within 14 days. This case is an example of the efficiency of the military MEDEVAC system on a global scale, ensuring optimum medical care for all service members deployed.