Gelatin maleimide microgels for hematopoietic progenitor cell encapsulation.

Hematopoietic stem cells (HSCs) are the apical cells of the hematopoietic system, giving rise to cells of the blood and lymph lineages. HSCs reside primarily within bone marrow niches that contain matrix and cell-derived signals that help inform stem cell fate. Aspects of the bone marrow microenvironment have been captured in vitro by encapsulating cells within hydrogel matrices that mimic native mechanical and biochemical properties. Hydrogel microparticles, or microgels, are increasingly being used to assemble granular biomaterials for cell culture and noninvasive delivery applications. Here, we report the optimization of a gelatin maleimide hydrogel system to create monodisperse gelatin microgels via a flow-focusing microfluidic process. We report characteristic hydrogel stiffness, stability, and swelling characteristics as well as encapsulation of murine hematopoietic stem and progenitor cells, and mesenchymal stem cells within microgels. Microgels support cell viability, confirming compatibility of the microfluidic encapsulation process with these sensitive bone marrow cell populations. Overall, this work presents a microgel-based gelatin maleimide hydrogel as a foundation for future development of a multicellular artificial bone marrow culture system.

General Direct Anticancer Effects of Deer Growing Antler Extract in Several Tumour Cell Lines, and Immune System-Mediated Effects in Xenograft Glioblastoma.

Deer antlers are the fastest growing tissue. Because they are based on proto-oncogenes, to avoid the risk of cancer, antlers evolved strong anticancer mechanisms, and thus their extract (DVA) is effective also against the few human tumours studied so far. We assessed whether DVA is a general anticancer compound by testing the direct effects in cells of different tumours: glioblastoma (GBM; lines U87MG and U251), colorectal (CRC; lines DLD-1, HT-29, SW480, and SW620), breast cancer (BRCA; lines MCF7, SKBR3, and PA00), and leukaemia (THP-1). DVA reduced the viability of tumours but not healthy cells (NHC; lines 293T and HaCaT). Mobility decreased at least for the longest test (72 h). Intraperitoneal/oral 200 mg DVA/kg administration in GBM xenograft mice for 28 d reduced tumour weight by 66.3% and 61.4% respectively, and it also reduced spleen weight (43.8%). In addition, tumours treated with DVA showed symptoms of liquefactive necrosis. Serum cytokines showed DVA up-regulated factors related to tumour fighting and down-regulated those related to inducing immune tolerance to the tumour. DVA shows general anticancer effects in the lines tested and, in GBM mice, also strong indirect effects apparently mediated by the immune system. DVA may contain a future anticancer medicine without secondary effects.

Biomaterial-Based Therapeutic Delivery of Immune Cells.

Immune cell therapy (ICT) is a transformative approach used to treat a wide range of diseases including type 1 diabetes, sickle cell disease, disorders of the hematopoietic system, and certain forms of cancers. Despite excellent clinical successes, the scope of adoptively transferred immune cells is limited because of toxicities like cytokine release syndrome and immune effector cell-associated neurotoxicity in patients. Furthermore, reports suggest that such treatment can impact major organ systems including cardiac, renal, pulmonary, and hepatic systems in the long term. Additionally, adoptively transferred immune cells cannot achieve significant penetration into solid tissues, thus limiting their therapeutic potential. Recent studies suggest that biomaterial-assisted delivery of immune cells can address these challenges by reducing toxicity, improving localization, and maintaining desired phenotypes to eventually regain tissue function. In this review, recent efforts in the field of biomaterial-based immune cell delivery for the treatment of diseases, their pros and cons, and where these approaches stand in terms of clinical treatment are highlighted.

FAK, vinculin, and talin control mechanosensitive YAP nuclear localization.

Focal adhesions (FAs) are nanoscale complexes containing clustered integrin receptors and intracellular structural and signaling proteins that function as principal sites of mechanotransduction in part via promoting the nuclear translocation and activation of the transcriptional coactivator yes-associated protein (YAP). Knockdown of FA proteins such as focal adhesion kinase (FAK), talin, and vinculin can prevent YAP nuclear localization. However, the mechanism(s) of action remain poorly understood. Herein, we investigated the role of different functional domains in vinculin, talin, and FAK in regulating YAP nuclear localization. Using genetic or pharmacological inhibition of fibroblasts and human mesenchymal stem cells (hMSCs) adhering to deformable substrates, we find that disruption of vinculin-talin binding versus talin-FAK binding reduces YAP nuclear localization and transcriptional activity via different mechanisms. Disruption of vinculin-talin binding or knockdown of talin-1 reduces nuclear size, traction forces, and YAP nuclear localization. In contrast, disruption of the talin binding site on FAK or elimination of FAK catalytic activity did not alter nuclear size yet still prevented YAP nuclear localization and activity. These data support both nuclear tension-dependent and independent models for matrix stiffness-regulated YAP nuclear localization. Our results highlight the importance of vinculin-talin-FAK interactions at FAs of adherent cells, controlling YAP nuclear localization and activity.

Encapsulation and immune protection for type 1 diabetes cell therapy.

Type 1 Diabetes (T1D) involves the autoimmune destruction of insulin-producing ß-cells in the pancreas. Exogenous insulin injections are the current therapy but are user-dependent and cannot fully recapitulate physiological insulin secretion dynamics. Since the emergence of allogeneic cell therapy for T1D, the Edmonton Protocol has been the most promising immunosuppression protocol for cadaveric islet transplantation, but the lack of donor islets, poor cell engraftment, and required chronic immunosuppression have limited its application as a therapy for T1D. Encapsulation in biomaterials on the nano-, micro-, and macro-scale offers the potential to integrate islets with the host and protect them from immune responses. This method can be applied to different cell types, including cadaveric, porcine, and stem cell-derived islets, mitigating the issue of a lack of donor cells. This review covers progress in the efforts to integrate insulin-producing cells from multiple sources to T1D patients as a form of cell therapy.

VEGF-delivering PEG hydrogels promote vascularization in the porcine subcutaneous space.

For cell therapies, the subcutaneous space is an attractive transplant site due to its large surface area and accessibility for implantation, monitoring, biopsy, and retrieval. However, its poor vascularization has catalyzed research to induce blood vessel formation within the site to enhance cell revascularization and survival. Most studies focus on the subcutaneous space of rodents, which does not recapitulate important anatomical features and vascularization responses of humans. Herein, we evaluate biomaterial-driven vascularization in the porcine subcutaneous space. Additionally, we report the first use of cost-effective fluorescent microspheres to quantify perfusion in the porcine subcutaneous space. We investigate the vascularization-inducing efficacy of vascular endothelial growth factor (VEGF)-delivering synthetic hydrogels based on 4-arm poly(ethylene) glycol macromers with terminal maleimides (PEG-4MAL). We compare three groups: a non-degradable hydrogel with a VEGF-releasing PEG-4MAL gel coating (Core+VEGF gel); an uncoated, non-degradable hydrogel (Core-only); and naïve tissue. After 2 weeks, Core+VEGF gel has significantly higher tissue perfusion, blood vessel area, blood vessel density, and number of vessels compared to both Core-only and naïve tissue. Furthermore, healthy vital signs during surgery and post-procedure metrics demonstrate the safety of hydrogel delivery. We demonstrate that VEGF-delivering synthetic hydrogels induce robust vascularization and perfusion in the porcine subcutaneous space.

Hydrolytic hydrogels tune mesenchymal stem cell persistence and immunomodulation for enhanced diabetic cutaneous wound healing.

Diabetes is associated with an altered global inflammatory state with impaired wound healing. Mesenchymal stem/stromal cells (MSC) are being explored for treatment of diabetic cutaneous wounds due to their regenerative properties. These cells are commonly delivered by injection, but the need to prolong the retention of MSC at sites of injury has spurred the development of biomaterial-based MSC delivery vehicles. However, controlling biomaterial degradation rates in vivo remains a therapeutic-limiting challenge. Here, we utilize hydrolytically degradable ester linkages to engineer synthetic hydrogels with tunable in vivo degradation kinetics for temporally controlled delivery of MSC. In vivo hydrogel degradation rate can be controlled by altering the ratio of ester to amide linkages in the hydrogel macromers. These hydrolytic hydrogels degrade at rates that enable unencumbered cutaneous wound healing, while enhancing the local persistence MSC compared to widely used protease-degradable hydrogels. Furthermore, hydrogel-based delivery of MSC modulates local immune responses and enhances cutaneous wound repair in diabetic mice. This study introduces a simple strategy for engineering tunable degradation modalities into synthetic biomaterials, overcoming a key barrier to their use as cell delivery vehicles.

Rapid and Facile Light-Based Approach to Fabricate Protease-Degradable Poly(ethylene glycol)-norbornene Microgels for Cell Encapsulation.

Thiol-norbornene photoclickable poly (ethylene glycol) (PEG)-based (PEG-NB) hydrogels are attractive biomaterials for cell encapsulation, drug delivery, and regenerative medicine applications. Although many crosslinking strategies and chemistries have been developed for PEG-NB bulk hydrogels, fabrication approaches of PEG-NB microgels have not been extensively explored. Here, a fabrication strategy for 4-arm amide-linked PEG-NB (PEG-4aNB) microgels using flow-focusing microfluidics for human mesenchymal stem/stromal cell (hMSCs) encapsulation is presented. PEG-4aNB photochemistry allows high-throughput, ultrafast generation, and cost-effective synthesis of monodispersed microgels (diameter 340 ± 18, 380 ± 24, and 420 ± 15 µm, for 6, 8, and 10 wt% of PEG-4aNB, respectively) using an in situ crosslinking methodology in a microfluidic device. PEG-4aNB microgels show in vitro degradability due to the incorporation of a protease-degradable peptide during photocrosslinking and encapsulated cells show excellent viability and metabolic activity for at least 13 days of culture. Furthermore, the secretory profile (i.e., MMP-13, ICAM-1, PD-L1, CXCL9, CCL3/MIP-1, IL-6, IL-12, IL-17E, TNF-α, CCL2/MCP-1) of encapsulated hMSCs shows increased expression in response to IFN-γ stimulation. Collectively, this work shows a versatile and facile approach for the fabrication of protease-degradable PEG-4aNB microgels for cell encapsulation.

Biomaterial therapeutic strategies for treatment of bacterial lung infections.

Bacterial infections of the lung frequently occur as a secondary infection to many respiratory viral infections and conditions, including influenza, COVID-19, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF). Currently, clinical standard treats bacterial infections of the lung with antibiotic drugs. However, the use of broad-spectrum antibiotics can disrupt host microbiomes, lead to patient discomfort, and current clinical settings face the constantly increasing threat of drug-resistant bacteria. Biofilms further obstruct effective treatment due to their protective matrix layer, which shields bacteria from both the host immune system and antimicrobial drugs and subsequently promotes drug resistance. Alternative antimicrobial agents, including bacteriophages and antimicrobial peptides, have been utilized to treat drug-resistant bacteria. However, these antimicrobial agents have significant limitations pertaining to their ability to arrive at infection sites without compromised function and ability to persist over an extended period to fully treat infections. Enhanced delivery strategies present great promise in addressing these issues by using micro/nanoparticle carriers that shield antimicrobial agents in transit and result in sustained release, enhancing subsequent therapeutic effect and can even be modulated to be multi-functional to further improve recovery following bacterial infection.

Combinatorial treatment rescues tumour-microenvironment-mediated attenuation of MALT1 inhibitors in B-cell lymphomas.

Activated B-cell-like diffuse large B-cell lymphomas (ABC-DLBCLs) are characterized by constitutive activation of nuclear factor κB driven by the B-cell receptor (BCR) and Toll-like receptor (TLR) pathways. However, BCR-pathway-targeted therapies have limited impact on DLBCLs. Here we used >1,100 DLBCL patient samples to determine immune and extracellular matrix cues in the lymphoid tumour microenvironment (Ly-TME) and built representative synthetic-hydrogel-based B-cell-lymphoma organoids accordingly. We demonstrate that Ly-TME cellular and biophysical factors amplify the BCR-MYD88-TLR9 multiprotein supercomplex and induce cooperative signalling pathways in ABC-DLBCL cells, which reduce the efficacy of compounds targeting the BCR pathway members Bruton tyrosine kinase and mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1). Combinatorial inhibition of multiple aberrant signalling pathways induced higher antitumour efficacy in lymphoid organoids and implanted ABC-DLBCL patient tumours in vivo. Our studies define the complex crosstalk between malignant ABC-DLBCL cells and Ly-TME, and provide rational combinatorial therapies that rescue Ly-TME-mediated attenuation of treatment response to MALT1 inhibitors.

Bioengineered omental transplant site promotes pancreatic islet allografts survival in non-human primates.

The transplanting islets to the liver approach suffers from an immediate posttransplant loss of islets of more than 50%, progressive graft dysfunction over time, and precludes recovery of grafts should there be serious complications such as the development of teratomas with grafts that are stem cell-derived islets (SC-islets). The omentum features an attractive extrahepatic alternative site for clinical islet transplantation. We explore an approach in which allogeneic islets are transplanted onto the omentum, which is bioengineered with a plasma-thrombin biodegradable matrix in three diabetic non-human primates (NHPs). Within 1 week posttransplant, each transplanted NHP achieves normoglycemia and insulin independence and remains stable until termination of the experiment. Success was achieved in each case with islets recovered from a single NHP donor. Histology demonstrates robust revascularization and reinnervation of the graft. This preclinical study can inform the development of strategies for ß cell replacement including the use of SC-islets or other types of novel cells in clinical settings.

Hydrogel delivery of purinergic enzymes improves cardiac ischemia/reperfusion injury.

RATIONALE: The innate immune response contributes to cardiac injury in myocardial ischemia/reperfusion (MI/R). Neutrophils are an important early part of the innate immune response to MI/R. Adenosine, an endogenous purine, is a known innate immune modulator and inhibitor of neutrophil activation. However, its delivery to the heart is limited by its short half-life (<30 s) and off-target side effects. CD39 and CD73 are anti-inflammatory homeostatic enzymes that can generate adenosine from phosphorylated adenosine substrate such as ATP released from injured tissue. OBJECTIVE: We hypothesize that hydrogel-delivered CD39 and CD73 target the local early innate immune response, reduce neutrophil activation, and preserve cardiac function in MI/R injury. METHODS AND RESULTS: We engineered a poly(ethylene) glycol (PEG) hydrogel loaded with the adenosine-generating enzymes CD39 and CD73. We incubated the hydrogels with neutrophils in vitro and showed a reduction in hydrogen peroxide production using Amplex Red. We demonstrated availability of substrate for the enzymes in the myocardium in MI/R by LC/MS, and tested release kinetics from the hydrogel. On echocardiography, global longitudinal strain (GLS) was preserved in MI/R hearts treated with the loaded hydrogel. Delivery of purinergic enzymes via this synthetic hydrogel resulted in lower innate immune infiltration into the myocardium post-MI/R, decreased markers of macrophage and neutrophil activation (NETosis), and decreased leukocyte-platelet complexes in circulation. CONCLUSIONS: In a rat model of MI/R injury, CD39 and CD73 delivered via a hydrogel preserve cardiac function by modulating the innate immune response.

Bariatric endoscopy, care-curative medicine and legal conflicts. Spanish Bariatric Endoscopy Group (Gettemo-SEED) Positioning.

Bariatric endoscopy treats obesity as a disease, in addition to its multiple associated comorbidities, so it should be considered in the "care-curative" field and not as "satisfying, voluntary or outcoming" medicine. Insufficient weight loss cases, or complications may occur. This, in parallel with the greater diffusion of these techniques, results an increase in the risk of complaints and judicial claims, which will presumably grow during next years. In this sense, we consider that all Bariatric Endoscopic Units working with medical-scientific rigor, must be able to be accredited and have legal support by the Scientific Societies. We propose to create a Medical-Legal Advisory Committee, composed of a medical team and a specialized law firm, which allows advising and guiding the endoscopist when incurring in a conflict.

Spanish Intragastric Balloon Consensus Statement (SIBC): practical guidelines based on experience of over 20 000 cases.

BACKGROUND: intragastric balloons (IGBs) are a minimally invasive, increasingly popular option for obesity treatment. However, there is only one worldwide guideline standardizing the technical aspects of the procedure (BIBC, SOARD 2018). OBJECTIVES: to construct a practical guideline for IGB usage by reproducing and expanding the BIBC survey among the Spanish Bariatric Endoscopy Group (GETTEMO). METHODS: a 140-question survey was submitted to all GETTEMO members. Twenty-one Spanish experienced endoscopists in IGBs answered back. Eight topics on patient selection, indications/contraindications, technique, multidisciplinary follow-up, results, safety, and financial/legal aspects were discussed. Consensus was defined as consensus ≥ 70 %. RESULTS: overall data included 20 680 IGBs including 12 different models. Mean age was 42.0 years-old, 79.9 % were women, and the mean preoperative body mass index (BMI) was 34.05 kg/m². Indication in BMI > 25 kg/m², 10 absolute contraindications, and nutritional and medication measures at follow-up were settled. A mean %TBWL (total body weight loss) of 17.66 % ± 2.5 % was observed. Early removal rate due to intolerance was 3.62 %. Adverse event rate was 0.70 % and 6.37 % for major and minor complications with consensual management. A single case of mortality occurred. IGBs were placed in private health, prior contract, and with full and single payment at the beginning. Seven lawsuits (0.034 %) were received, all ran through civil proceeding, and with favorable final resolution. CONCLUSIONS: this consensus based on more than 20 000 cases represents practical recommendations to perform IGB procedures. This experience shows that the device leads to satisfactory weight loss with a low rate of adverse events. Most results are reproducible compared to those obtained by the BIBC.

Adhesive peptide and polymer density modulate 3D cell traction forces within synthetic hydrogels.

Cell-extracellular matrix forces provide pivotal signals regulating diverse physiological and pathological processes. Although mechanobiology has been widely studied in two-dimensional configurations, limited research has been conducted in three-dimensional (3D) systems due to the complex nature of mechanics and cellular behaviors. In this study, we established a platform integrating a well-defined synthetic hydrogel system (PEG-4MAL) with 3D traction force microscopy (TFM) methodologies to evaluate deformation and force responses within synthetic microenvironments, providing insights that are not tractable using biological matrices because of the interdependence of biochemical and biophysical properties and complex mechanics. We dissected the contributions of adhesive peptide density and polymer density, which determines hydrogel stiffness, to 3D force generation for fibroblasts. A critical threshold of adhesive peptide density at a constant matrix elasticity is required for cells to generate 3D forces. Furthermore, matrix displacements and strains decreased with matrix stiffness whereas stresses, and tractions increased with matrix stiffness until reaching constant values at higher stiffness values. Finally, Rho-kinase-dependent contractility and vinculin expression are required to generate significant 3D forces in both collagen and synthetic hydrogels. This research establishes a tunable platform for the study of mechanobiology and provides new insights into how cells sense and transmit forces in 3D.

Host type 2 immune response to xenogeneic serum components impairs biomaterial-directed osteo-regenerative therapies.

The transformative potential of cells as therapeutic agents is being realized in a wide range of applications, from regenerative medicine to cancer therapy to autoimmune disorders. The majority of these therapies require ex vivo expansion of the cellular product, often utilizing fetal bovine serum (FBS) in the culture media. However, the impact of residual FBS on immune responses to cell therapies and the resulting cell therapy outcomes remains unclear. Here, we show that hydrogel-delivered FBS elicits a robust type 2 immune response characterized by infiltration of eosinophils and CD4+ T cells. Host secretion of cytokines associated with type 2 immunity, including IL-4, IL-5, and IL-13, is also increased in FBS-containing hydrogels. We demonstrate that the immune response to xenogeneic serum components dominates the local environment and masks the immunomodulatory effects of biomaterial-delivered mesenchymal stromal/stem cells. Importantly, delivery of relatively small amounts of FBS (3.2% by volume) within BMP-2-containing biomaterial constructs dramatically reduces the ability of these constructs to promote de novo bone formation in a radial defect model in immunocompetent mice. These results urge caution when interpreting the immunological and tissue repair outcomes in immunocompetent pre-clinical models from cells and biomaterial constructs that have come in contact with xenogeneic serum components.

Analyzing immune response to engineered hydrogels by hierarchical clustering of inflammatory cell subsets.

Understanding the immune response to hydrogel implantation is critical for the design of immunomodulatory biomaterials. To study the progression of inflammation around poly(ethylene glycol) hydrogels presenting Arg-Gly-Asp (RGD) peptides and vascular endothelial growth factor, we used temporal analysis of high-dimensional flow cytometry data paired with intravital imaging, immunohistochemistry, and multiplexed proteomic profiling. RGD-presenting hydrogels created a reparative microenvironment promoting CD206+ cellular infiltration and revascularization in wounded dorsal skin tissue. Unbiased clustering algorithms (SPADE) revealed significant phenotypic transition shifts as a function of the cell-adhesion hydrogel properties. SPADE identified an intermediate macrophage subset functionally regulating in vivo cytokine secretion that was preferentially recruited for RGD-presenting hydrogels, whereas dendritic cell subsets were preferentially recruited to RDG-presenting hydrogels. Last, RGD-presenting hydrogels controlled macrophage functional cytokine secretion to direct polarization and vascularization. Our studies show that unbiased clustering of single-cell data provides unbiased insights into the underlying immune response to engineered materials.

Synthetic Matrix Scaffolds Engineer the In Vivo Tumor Immune Microenvironment for Immunotherapy Screening.

Immunotherapy has emerged as one of the most powerful anti-cancer therapies but is stymied by the limits of existing preclinical models with respect to disease latency and reproducibility. Additionally, the influence of differing immune microenvironments within tumors observed clinically and associated with immunotherapeutic resistance cannot be tuned to facilitate drug testing workflows without changing model system or laborious genetic approaches. To address this testing platform gap in the immune oncology drug development pipeline, the authors deploy engineered biomaterials as scaffolds to increase tumor formation rate, decrease disease latency, and diminish variability of immune infiltrates into tumors formed from murine mammary carcinoma cell lines implanted into syngeneic mice. By altering synthetic gel formulations that reshape infiltrating immune cells within the tumor, responsiveness of the same tumor model to varying classes of cancer immunotherapies, including in situ vaccination with a molecular adjuvant and immune checkpoint blockade, diverge. These results demonstrate the significant role the local immune microenvironment plays in immunotherapeutic response. These engineered tumor immune microenvironments therefore improve upon the limitations of current breast tumor models used for immune oncology drug screening to enable immunotherapeutic testing relevant to the variability in tumor immune microenvironments underlying immunotherapeutic resistance seen in human patients.

Endoscopic view of the intrahepatic biliary ducts by direct per-oral cholangioscopy in a patient with a choledochal cyst.

Sixty year old female with hypertension and crampy abdominal pain episodes. Admitted to hospital (September-2020) by obstructive jaundice. MRCP: biliary dilation due to Todani Ic (fusiform) choledocal cyst (CC), distal sludge. ERCP: normal mucosa prominent papilla; biliary dilation compatible with CC; choledocholithiasis; 8-mm CHD filling defect. Sphincterotomy, removal of stones/sludge, brush-cytology of the filling defect (pathology: atypias). US: dilation resolution (CBD: 6.5 mm).

Bacteriophage-Loaded Poly(lactic-co-glycolic acid) Microparticles Mitigate Staphylococcus aureus Infection and Cocultures of Staphylococcus aureus and Pseudomonas aeruginosa.

Lung infections caused by Gram-positive Staphylococcus aureus (S. aureus) and coinfections caused by S. aureus and Gram-negative Pseudomonas aeruginosa (P. aeruginosa) are challenging to treat, especially with the rise in the number of antibiotic-resistant strains of these pathogens. Bacteriophage (phage) are bacteria-specific viruses that can infect and lyse bacteria, providing a potentially effective therapy for bacterial infections. However, the development of bacteriophage therapy is impeded by limited suitable biomaterials that can facilitate effective delivery of phage to the lung. Here, the ability of porous microparticles engineered from poly(lactic-co-glycolic acid) (PLGA), a biodegradable polyester, to effectively deliver phage to the lung, is demonstrated. The phage-loaded microparticles (phage-MPs) display potent antimicrobial efficacy against various strains of S. aureus in vitro and in vivo, and arrest the growth of a clinical isolate of S. aureus in the presence of sputum supernatant obtained from cystic fibrosis patients. Moreover, phage-MPs efficiently mitigate in vitro cocultures of S. aureus and P. aeruginosa and display excellent cytocompatibility with human lung epithelial cells. Therefore, phage-MPs represents a promising therapy to treat bacterial lung infection.