Suitability of Alternative Protein Foods for Agroecological Approaches to Address Nutrition in Low- and Middle-Income Countries

Agroecology has been proposed as a holistic approach to transform food systems that meet global food requirements with favorable environmental and social impacts. Agroecology relies on science, practices, and social movements that emphasize ecological principles, local knowledge, culture, and traditions to increase the sustainability and equity of the food system. Agroecological practices have demonstrated positive outcomes on food security and nutrition in low- and middle-income countries (LMICs). Agroecology principles can be applied across the food system and could facilitate the integration of certain alternative protein (AP) foods to address multiple issues. In this perspective, agroecological principles were analyzed to compare the suitability of different AP sources: unprocessed/minimally processed legumes, plant-based meats, edible insects, macroalgae (seaweed), fungal biomass, and cultivated meat. Considerations were identified for the feasibility of AP adoption in LMICs within an agroecological framework to provide nutrient-rich and sustainable diets while addressing other principles such as fairness and economic diversity. From this analysis, legumes, simplified plant-based meat analogs such as texturized plant proteins with minimal additives, edible insects, and macroalgae (location dependent) would make excellent nutritional contributions alongside animal-sourced food within LMICs within an agroecological framework. In contrast, highly processed plant-based meats, fungal biomass, and cultivated meat do not align well with agroecological principles for large-scale human consumption within LMICs. Furthermore, the production facilities to make these foods require robust capital investment and there may be issues related to who owns the intellectual property of these technologies. The NOVA classification system categorizes food based on the degree of processing. Our assessment suggests that foods with lower NOVA classification of unprocessed and minimally processed best fit the agroecological principles related to nutrition, agroecosystem, and societal demands for sustainable food systems.

What Is the Likely Impact of Alternative Proteins on Diet Quality, Health, and the Environment in Low- and Middle-Income Countries

Alternative protein (AP) foods are proposed to support a global protein transition. Whereas AP food innovation has been a strategy to promote consumption of protein sources with low environmental impact in high-income countries (HICs) diets, their relation to sustainable, high-quality diets in low- and middle-income countries (LMICs) remains to be established. AP foods vary in nutrient profile, processing requirements, costs, and environmental impact. Current literature regarding AP suitability in LMIC contexts is limited. This perspective examined environmental and nutritional metrics that can assess the sustainability of AP in LMICs. Current research areas needed to accurately assess environmental impacts while considering nutritional density were identified. An overview of the usability of relevant AP in both high- and low-resource settings was also explored. Metrics addressing diverse contextual synergies in LMICs, unifying nutritional, environmental, and socioeconomic considerations, were found necessary to guide the integration of AP into LMIC diets.

Age-associated Senescent - T Cell Signaling Promotes Type 3 Immunity that Inhibits the Biomaterial Regenerative Response

Aging is associated with immunological changes that compromise response to infections and vaccines, exacerbate inflammatory diseases and can potentially mitigate tissue repair. Even so, age-related changes to the immune response to tissue damage and regenerative medicine therapies remain unknown. Here, it is characterized how aging induces changes in immunological signatures that inhibit tissue repair and therapeutic response to a clinical regenerative biological scaffold derived from extracellular matrix. Signatures of inflammation and interleukin (IL)-17 signaling increased with injury and treatment both locally and regionally in aged animals, and computational analysis uncovered age-associated senescent-T cell communication that promotes type 3 immunity in T cells. Local inhibition of type 3 immune activation using IL17-neutralizing antibodies improves healing and restores therapeutic response to the regenerative biomaterial, promoting muscle repair in older animals. These results provide insights into tissue immune dysregulation that occurs with aging that can be targeted to rejuvenate repair.

Transfer learning in a biomaterial fibrosis model identifies in vivo senescence heterogeneity and contributions to vascularization and matrix production across species and diverse pathologies

Cellular senescence is a state of permanent growth arrest that plays an important role in wound healing, tissue fibrosis, and tumor suppression. Despite senescent cells' (SnCs) pathological role and therapeutic interest, their phenotype in vivo remains poorly defined. Here, we developed an in vivo-derived senescence signature (SenSig) using a foreign body response-driven fibrosis model in a p16-CreERT2;Ai14 reporter mouse. We identified pericytes and "cartilage-like" fibroblasts as senescent and defined cell type-specific senescence-associated secretory phenotypes (SASPs). Transfer learning and senescence scoring identified these two SnC populations along with endothelial and epithelial SnCs in new and publicly available murine and human data single-cell RNA sequencing (scRNAseq) datasets from diverse pathologies. Signaling analysis uncovered crosstalk between SnCs and myeloid cells via an IL34-CSF1R-TGFβR signaling axis, contributing to tissue balance of vascularization and matrix production. Overall, our study provides a senescence signature and a computational approach that may be broadly applied to identify SnC transcriptional profiles and SASP factors in wound healing, aging, and other pathologies.

Helminth egg derivatives as proregenerative immunotherapies

The immune system is increasingly recognized as an important regulator of tissue repair. We developed a regenerative immunotherapy from the helminth Schistosoma mansoni soluble egg antigen (SEA) to stimulate production of interleukin (IL)-4 and other type 2-associated cytokines without negative infection-related sequelae. The regenerative SEA (rSEA) applied to a murine muscle injury induced accumulation of IL-4-expressing T helper cells, eosinophils, and regulatory T cells and decreased expression of IL-17A in gamma delta (γδ) T cells, resulting in improved repair and decreased fibrosis. Encapsulation and controlled release of rSEA in a hydrogel further enhanced type 2 immunity and larger volumes of tissue repair. The broad regenerative capacity of rSEA was validated in articular joint and corneal injury models. These results introduce a regenerative immunotherapy approach using natural helminth derivatives.

Autologous Protein Solution processing alters lymphoid and myeloid cell populations and modulates gene expression dependent on cell type

Osteoarthritis (OA) is a degenerative disease associated with cartilage degradation, osteophyte formation, and fibrillation. Autologous Protein Solution (APS), a type of autologous anti-inflammatory orthobiologic, is used for pain management and treatment of OA. Various compositions of autologous PRP formulations are in clinical use for musculoskeletal pathologies, by nature of their minimal processing and source of bioactive molecules. Currently, there is no consensus on the optimal composition of the complex mixture. In this study, we focused on elucidating the immune cell subtypes and phenotypes in APS. We identified the immune cell types in APS from healthy donors and investigated phenotypic changes in the immune cells after APS processing. Based on flow cytometric analysis, we found that neutrophils and T cells are the most abundant immune cell types in APS, while monocytes experience the largest fold change in concentration compared to WBCs. Gene expression profiling revealed that APS processing results in differential gene expression changes dependent on immune cell type, with the most significantly differentially regulated genes occurring in the monocytes. Our results demonstrate that the mechanical processing of blood, whose main purpose is enrichment and separation, can alter its protein and cellular composition, as well as cellular phenotypes in the final product.

Biomaterials direct functional B cell response in a material-specific manner

B cells are an adaptive immune target of biomaterials development in vaccine research but, despite their role in wound healing, have not been extensively studied in regenerative medicine. To probe the role of B cells in biomaterial scaffold response, we evaluated the B cell response to biomaterial materials implanted in a muscle wound using a biological extracellular matrix (ECM), as a reference for a naturally derived material, and synthetic polyester polycaprolactone (PCL), as a reference for a synthetic material. In the local muscle tissue, small numbers of B cells are present in response to tissue injury and biomaterial implantation. The ECM materials induced mature B cells in lymph nodes and antigen presentation in the spleen. The synthetic PCL implants resulted in prolonged B cell presence in the wound and induced an antigen-presenting phenotype. In summary, the adaptive B cell immune response to biomaterial induces local, regional, and systemic immunological changes.

IL-17 and immunologically induced senescence regulate response to injury in osteoarthritis

Senescent cells (SnCs) are implicated in the pathogenesis of age-related diseases including osteoarthritis (OA), in part via expression of a senescence-associated secretory phenotype (SASP) that includes immunologically relevant factors and cytokines. In a model of posttraumatic OA (PTOA), anterior cruciate ligament transection (ACLT) induced a type 17 immune response in the articular compartment and draining inguinal lymph nodes (LNs) that paralleled expression of the senescence marker p16INK4a (Cdkn2a) and p21 (Cdkn1a). Innate lymphoid cells, γδ+ T cells, and CD4+ T cells contributed to IL-17 expression. Intra-articular injection of IL-17-neutralizing antibody reduced joint degeneration and decreased expression of the senescence marker Cdkn1a. Local and systemic senolysis was required to attenuate tissue damage in aged animals and was associated with decreased IL-17 and increased IL-4 expression in the articular joint and draining LNs. In vitro, we found that Th17 cells induced senescence in fibroblasts and that SnCs skewed naive T cells toward Th17 or Th1, depending on the presence of TGF-β. The SASP profile of the inflammation-induced SnCs included altered Wnt signaling, tissue remodeling, and cell-cycle pathways not previously implicated in senescence. These findings provide molecular targets and mechanisms for senescence induction and therapeutic strategies to support tissue healing in an aged environment.

Characterization of Tensioned PDMS Membranes for Imaging Cytometry on Microraft Arrays

Polydimethylsiloxane (PDMS) membranes can act as sensing elements, barriers, and substrates, yet the low rigidity of the elastomeric membranes can limit their practical use in devices. Microraft arrays rely on a freestanding PDMS membrane as a substrate for cell arrays used in imaging cytometry and cellular isolation. However, the underlying PDMS membrane deforms under the weight of the cell media, making automated analytical microscopy (and thus cytometry and cell isolation) challenging. Here we report the development of microfabrication strategies and physically motivated mathematical modeling of membrane deformation of PDMS microarrays. Microraft arrays were fabricated with mechanical tension stored within the PDMS substrate. These membranes deformed 20× less than that of arrays fabricated using prior methods. Modeling of the deformation of pretensioned arrays using linear membrane theory yielded ≤15% error in predicting the array deflection and predicted the impact of cure temperatures up to 120 °C. A mathematical approach was developed to fit models of microraft shape to sparse real-world shape measurements. Automated imaging of cells on pretensioned microarrays using the focal planes predicted by the model produced high quality fluorescence images of cells, enabling accurate cell area quantification (<4% error) at increased speed (13×) relative to conventional methods. Our microfabrication method and simplified, linear modeling approach is readily applicable to control the deformation of similar membranes in MEMs devices, sensors, and microfluidics.

Nonsteroidal Anti-Inflammatory Drug-Induced Leaky Gut Modeled Using Polarized Monolayers of Primary Human Intestinal Epithelial Cells

The intestinal epithelium provides a critical barrier that separates the gut microbiota from host tissues. Nonsteroidal anti-inflammatory drugs (NSAIDs) are efficacious analgesics and antipyretics and are among the most frequently used drugs worldwide. In addition to gastric damage, NSAIDs are toxic to the intestinal epithelium, causing erosions, perforations, and longitudinal ulcers in the gut. Here, we use a unique in vitro human primary small intestinal cell monolayer system to pinpoint the intestinal consequences of NSAID treatment. We found that physiologically relevant doses of the NSAID diclofenac (DCF) are cytotoxic because they uncouple mitochondrial oxidative phosphorylation and generate reactive oxygen species. We also find that DCF induces intestinal barrier permeability, facilitating the translocation of compounds from the luminal to the basolateral side of the intestinal epithelium. The results we outline here establish the utility of this novel platform, representative of the human small intestinal epithelium, to understand NSAID toxicity, which can be applied to study multiple aspects of gut barrier function including defense against infectious pathogens and host-microbiota interactions.

Shape memory activation can affect cell seeding of shape memory polymer scaffolds designed for tissue engineering and regenerative medicine

The ability of a three-dimensional scaffold to support cell seeding prior to implantation is a critical criterion for many scaffold-based tissue engineering and regenerative medicine strategies. Shape memory polymer functionality may present important new opportunities and challenges in cell seeding, but the extent to which shape memory activation can positively or negatively affect cell seeding has yet to be reported. The goal of this study was to determine whether shape memory activation can affect cell seeding. The hypothesis was that shape memory activation of porous scaffolds during cell seeding can affect both the number of cells seeded in a scaffold and the distribution (in terms of average infiltration distance) of cells following seeding. Here, we used a porous shape memory foam scaffold programmed to expand when triggered to study cell number and average cell infiltration distance following shape memory activation. We found that shape memory activation can affect both the number of cells and the average cell infiltration distance. The effect was found to be a function of rate of shape change and scaffold pore interconnectivity. Magnitude of shape change had no effect. Only reductions in cell number and infiltration distance (relative to control and benchmark) were observed. The findings suggest that strategies for tissue engineering and regenerative medicine that involve shape memory activation in the presence of a cell-containing medium in vitro or in vivo should consider how recovery rate and scaffold pore interconnectivity may ultimately impact cell seeding.