Alternative fat: redefining adipocytes for biomanufacturing cultivated meat

Novel Protein-Rich Bioactive Bioink Stimulates Cellular Proliferation and Response in 3D Bioprinted Volumetric Constructs

3D extrusion bioprinting, a promising and widely adopted technology in the emerging field of biofabrication, has gained considerable attention for its ability to fabricate hierarchically structured, native-mimicking tissue substitutes with precisely defined cell distributions. Despite notable advancements, the limited availability of suitably bioactive bioinks remains a major challenge, hindering the construction of volumetric tissue substitutes effectively mimicking biological functionality. Therefore, this work proposes a protein-rich, low-cost, bioactive bioink: abundantly available eggwhite powder (EWP) is leveraged to functionalize an alginate-methylcellulose (AlgMC) hydrogel matrix and enhance cellular response. The developed EWP-supplemented bioinks not only maintain favorable printability and high shape fidelity but also exhibit remarkable bioactivity. Notably, incorporating EWP into AlgMC-based bioinks enhances shear-thinning features, thereby improving the viability of encapsulated cells within the bioprinted constructs. The versatility and biofunctionality of EWP in bioprinted constructs are demonstrated using three distinct cell types, encompassing sources such as a stem cell line, human soft skin, and stiff bone tissues. Furthermore, the promising and wide applicability of the EWP-supplemented bioink for biofabrication is demonstrated exemplarily in core-shell and multi-channel bioprinting strategies as a proof-of-concept for functional tissue construction. These findings underscore the significant and versatile potential of this novel bioink in biofabrication and biomedical applications.

Characterization of the differences in lipid profiles and volatile compounds of adipose stem cells adipogenic differentiation and adipocytic transdifferentiation of muscle stem cells from large yellow croakers based on UPLC-MS/MS and GC-IMS

Lipids contribute significantly to the flavor of cell-cultured fish meat as precursor components of flavor compounds. Here, we initially reported the differences in lipid metabolite profiles and volatile compounds between adipogenic differentiation of adipose stem cells (ASCs) and adipocytic transdifferentiation of muscle stem cells (MSCs) from large yellow croakers. A total of 2106 lipid metabolites were identified by UPLC-MS/MS. Compared with the MSCs group, 1263 differentially expressed lipid metabolites were found in the ASCs group, with 1026 up-regulated lipid metabolites and 237 down-regulated ones. The main lipid differences were fatty acyls (FAs) and glycerolipids (GL). GC-IMS identified a total of 47 volatile compounds. Volatile compounds such as ethyl laurate, nonanal, and 2,3-pentanedione were significantly higher in the ASCs group than in the MSCs group. GC-IMS results indicated that the ASCs group was more flavorful. This study provides a theoretical basis for developing cell-cultured fish meat with a familiar flavor.

Development of a biomarker panel for cell characterization intended for cultivated meat

Cultivated meat has in recent years been suggested as a sustainable alternative to produce meat at large-scale. Several aspects of cultivated meat production have demonstrated significant progress. However, there are still many questions regarding the cell culture, media composition, and the production itself to be answered and optimized. Finding good starter cell populations is a challenge to address and requires robust tools to characterize the cell populations. Detailed analysis is required to identify each type of cell within the skeletal muscle niche leads to optimized cultivated meat production at large-scale. In this study, we developed a set of biomarkers, using digital droplet PCR (ddPCR) and Immunofluorescence (IF) staining, to identify specific cell types within a heterogeneous cell population isolated from skeletal muscle tissue. We showed that combining Neural Cell Adhesion Molecule (NCAM), Calponin 1 (CNN1), and Fibronectin (FN), can be a powerful approach to predict the growth of skeletal myotubes, smooth muscle mesenchymal cells (SMMCs), and myofibroblasts, respectively. Moreover, early cell-cell interactions of fibroblastic cells were observed to be triggered through thin actin filaments containing CNN1 protein, to form, subsequently, myofibroblast networks. Besides, Myogenic Differentiation 1 (MyoD) is the key marker to detect skeletal muscle growth, whereas Myogenic Factor 5 (MyF5) can be expressed in myogenic and non-myogenic cells. MyF5 was detected at differentiation stages within the myotube nuclei, suggesting an unknown role during myotube formation.

Review: Livestock cell types with myogenic differentiation potential: Considerations for the development of cultured meat

With the current environmental impact of large-scale animal production and societal concerns about the welfare of farm animals, researchers are questioning whether we can cultivate animal cells for the purpose of food production. This review focuses on a pivotal aspect of the cellular agriculture domain: cells. We summarised information on the various cell types from farm animals currently used for the development of cultured meat, including mesenchymal stromal cells, myoblasts, and pluripotent stem cells. The review delves into the advantages and limitations of each cell type and considers factors like the selection of the appropriate cell source, as well as cell culture conditions that influence cell performance. As current research in cultured meat seeks to create muscle fibers to mimic the texture and nutritional profile of meat, we focused on the myogenic differentiation capacity of the cells. The most commonly used cell type for this purpose are myoblasts or satellite cells, but given their limited proliferation capacity, efforts are underway to formulate myogenic differentiation protocols for mesenchymal stromal cells and pluripotent stem cells. The multipotent character of the latter cell types might enable the creation of other tissues found in meat, such as adipose and connective tissues. This review can help guiding the selection of a cell type or culture conditions in the context of cultured meat development.

Can cell-cultured meat from stem cells pave the way for sustainable alternative protein?

As the global population grows, the demand for food and animal-derived products rises significantly, posing a notable challenge to the progress of society in general. Alternative protein production may adequately address such a challenge, and cell-based meat production emerges as a promising solution. This review investigates methodologies for in vitro myogenesis and adipogenesis from stem cells (adult, embryonic, or induced pluripotent stem cells - iPSCs) across different animal species, as well as the remaining challenges for scalability, the possibility of genetic modification, along with safety concerns regarding the commercialization of cell-cultured meat. Regarding such complexities, interdisciplinary approaches will be vital for assessing the potential of cell-cultured meat as a sustainable protein source, mimicking the sensory and nutritional attributes of conventional livestock meat whilst meeting the demands of a growing global population while mitigating environmental impacts.

bta-miR-484 Inhibits Bovine Intramuscular Adipogenesis by Regulating Mitotic Clonal Expansion via the MAP3K9/JNK/CCND1 Axis

Intramuscular fat (IMF) content is a critical indicator of the beef nutritional value and flavor. In this study, we focused on bta-miR-484, a microRNA that is differentially expressed during the adipogenic differentiation of bovine intramuscular adipocytes and is negatively correlated with the IMF content across different cattle breeds. Our findings demonstrate that bta-miR-484 inhibits adipogenic differentiation without altering the fatty acid composition of bovine intramuscular adipocytes. miRNA pull-down and dual-luciferase reporter assays confirmed that MAP3K9 is a target gene of bta-miR-484. Furthermore, bta-miR-484 suppresses the JNK signaling pathway by targeting MAP3K9, leading to decreased CCND1 expression, which impedes the mitotic clonal expansion (MCE) process and inhibits intramuscular adipocyte differentiation. In summary, this study uncovers a novel mechanism by which bta-miR-484 regulates bovine IMF content and provides the first exploration of MCE during intramuscular adipocyte adipogenic differentiation. These findings offer valuable theoretical insights into beef cattle breeding and molecular improvements.

Utilizing superheated steam to prepare traditional Chinese twice-cooked pork bellies, exploring its effects on the texture and flavor of fat layers

Fat greatly impacts the overall texture and flavor of pork belly. Twice-cooked pork bellies (TPB), typically boiled and sliced before "back to pot" being stir-fried, is a classic Sichuan cuisine among stir-fried dishes. In this study, the effects of substituting conventional pan-frying (PCV) with superheated steam (SHS) technology on the sensory, texture, microstructure and flavor of the fat layers were investigated. SHS was used as an alternative to boiling (120 °C for 15, 20, 25, and 30 min), and "back to pot" stir-frying was also by SHS. TPB precooked for 25 min (P25) with SHS performed better quality characteristics than PCV, with less collagen fiber disruption and lipid droplet area, resulting in a lower hardness and higher shear force. Besides, the low-oxygen environment of SHS retarded the lipid peroxidation, showing a significantly lower MDA content than PCV. Differently, PCV exhibited more grassy and fatty flavors, while P25 exhibited a unique aroma of fruity and creamy due to its higher UFA/SFA ratios in the pre-cooking stage. Overall, the sensory scores of P25 were comparable to those of PCV (with no significant difference), revealing that SHS is expected to be applied to the industrial production of stir-fried dishes.

Acetate cellulose fibrous scaffold is suitable for cultivated fat production

Fat is an essential component of meat which contributes to its sensory characteristics. Therefore, producing cultivated fat is essential to replicate the texture, flavor, and juiciness of conventional meat. One of the challenges in obtaining cultivated fat is that once adipocytes reach differentiation in culture, they tend to float. In this study, we tested whether immortalized pre-adipocytes could be viable, grow, and differentiate when cultivated onto a fibrous scaffold produced by the electrospun of cellulose acetate. Our results demonstrated that the cells attach, proliferate, colonize, and differentiate into mature adipocytes in the three-dimensional fibrous structure during the culture period. Moreover, when layers of the scaffold containing differentiated cells were stacked, it acquired a characteristic similar to conventional animal fat. Therefore, this research suggests that fibrous scaffolds produced using cellulose acetate are a promising substrate for producing cultivated fat.

Dynamically cultured, differentiated bovine adipose-derived stem cell spheroids as building blocks for biofabricating cultured fat

Cultured or cultivated meat, animal muscle, and fat tissue grown in vitro, could transform the global meat market, reducing animal suffering while using fewer resources than traditional meat production and no antimicrobials at all. To ensure the appeal of cultured meat to future customers, cultured fat is essential for achieving desired mouthfeel, taste, and texture, especially in beef. In this work we show the establishment of primary bovine adipose-derived stem cell spheroids in static and dynamic suspension culture. Spheroids are successfully differentiated using a single-step protocol. Differentiated spheroids from dynamic cultures maintain stability and viability during 3D bioprinting in edible gellan gum. Also, the fatty acid composition of differentiated spheroids is significantly different from control spheroids. The cells are cultured antibiotic-free to minimize the use of harmful substances. This work presents a stable and bioprintable building block for cultured fat with a high cell density in a 3D dynamic cell culture system.

Chicken Embryo Fibroblast Viability and Trans-Differentiation Potential for Cultured Meat Production Across Passages

This study was conducted to analyze the viability of primary chicken embryo fibroblasts and the efficiency of adipogenic trans-differentiation for cultured meat production. In isolating chicken embryo fibroblasts (CEFs) from a heterogeneous cell pool containing chicken satellite cells (CSCs), over 90% of CEFs expressed CD29 and vimentin. The analysis of the proliferative capabilities of CEFs revealed no significant differences in EdU-positive cells (%), cumulative cell number, doubling time, and growth rate from passage 1 to passage 9 (p > 0.05). This indicates that CEFs can be isolated by 2 h of pre-plating and survive stably up to passage 9, and that primary fibroblasts can serve as a valuable cell source for the cultured meat industry. Adipogenic trans-differentiation was induced up to passage 9 of CEFs. As passages increased, lipid accumulation and adipocyte size significantly decreased (p < 0.05). The reduced differentiation rate of primary CEFs with increasing passages poses a major challenge to the cost and efficiency of cultured meat production. Thus, effective cell management and the maintenance of cellular characteristics for a long time are crucial for ensuring stable and efficient cultured fat production in the cultured meat industry.

Optimization of differentiation conditions for porcine adipose-derived mesenchymal stem cells and analysis of fatty acids in cultured fat

Cultured fat is an important part of cultured meat, and the ability of adipose-derived mesenchymal stem cells (ADSCs) to differentiate into mature adipose tissue affects the quality of cultured fat. Thus, the primary aim of this study was to screen for combinations of differentiation-inducing factors (DIF) using single-factor experiment and orthogonal experimental design under two-dimensional culture conditions for ADSCs. The results showed that a combination of DIF consisting of 1 μmol/L dexamethasone, 0.1 mmol/L 3-isobutyl-1-methylxanthine, 10 μg/mL insulin, 0.1 mmol/L indomethacin, and 2 μmol/L rosiglitazone was a good choice for the differentiation of ADSCs. An combination of DIF was applied to the preparation of cultured fat with collagen as scaffolds. Forty-eight fatty acids were detected in cultured fat by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Among them, the content of twenty-one fatty acids in cultured fat was significantly higher than that of conventional porcine subcutaneous adipose tissue (P < 0.05), and the content of 14 fatty acids was not significantly different (P > 0.05). The ratio of ω-6 polyunsaturated fatty acids content to ω-3 polyunsaturated fatty acids content was 1.23:1, which meant cultured fat was beneficial for human health. This study provides a method to improve the differentiation ability of ADSCs while also providing a reference for indicating the nutritional value of cultured fat.

Enhancing the palatability of cultivated meat

Cultivated meat (CM) has transitioned from a futuristic concept to a present reality, with select products approved for consumption and sale in Singapore, Israel, and the USA. This evolution has emphasized scalable, cost-effective, and sustainable production, as well as navigation of regulatory pathways. As CM develops, a crucial challenge lies in delivering products that are highly appealing to consumers. Central to this will be refining CM palatability, a term encompassing food's taste, aroma, texture, tenderness, juiciness, and color. We explore the scientific and engineering approaches to producing palatable CM, including cell-line selection, cell differentiation, and post-processing techniques. This includes a discussion of the structural and compositional properties of meat that are intrinsically coupled to palatability.

Chemical and sensory analyses of cultivated pork fat tissue as a flavor enhancer for meat alternatives

The emerging field of cellular agriculture has accelerated the development of cell-cultivated adipose tissue as an additive to enhance the flavor of alternative meat products. However, there has been limited research to evaluate the sensory profile of in vitro-grown tissues compared to conventionally obtained animal fat. This study aimed to investigate the aromatic characteristics of cell-cultivated fat tissue as a flavor enhancer for meat alternatives. Porcine dedifferentiated fat (PDFAT) cells were clonally isolated and differentiated into adipocytes. This cultured adipose tissue was then analyzed alongside native porcine fat using gas chromatography-mass spectrometry (GC/MS) coupled with descriptive sensory analysis by human consumers. This evaluation enabled quantitative and qualitative assessments of volatile compounds released during cooking for both in vitro and in vivo porcine fats. The volatile profiles generated during the cooking process and fatty aroma characteristics reported by sensory consumers were largely similar between the two fat sources, with some differences in select compounds and aroma attributes. Ultimately, the consumers found comparable overall liking scores reported between the conventional and cultured porcine fats. These findings provide valuable sensory evidence supporting the viability of cell-cultivated adipose tissue as a flavor component of meat alternatives, substituting for conventional animal fat.

Optimized Adipogenic Differentiation and Delivery of Bovine Umbilical Cord Stem Cells for Cultivated Meat

Cultivated meat, also known as cell-based or clean meat, utilizes mesenchymal stem cells to cultivate mature cell types like adipocytes, which are pivotal for imparting the desired taste and texture. The delivery of differentiated cells, crucial in cultivated meat production, is facilitated through extensive exploration of 3D culturing techniques mimicking physiological environments. In this study, we investigated the adipogenic differentiation potential of bovine umbilical cord stem cells (BUSCs), sourced from discarded birth tissue, and assessed the feasibility of delivering differentiated cells for cultivated meat using gelatin methacrylate (GelMA) as a carrier for adipose tissue. Various adipogenic inducers, previously reported to be effective for human mesenchymal stem cells (hMSCs), were evaluated individually or in combination for their efficacy in promoting the adipogenesis of BUSCs. Surprisingly, while the traditional adipogenic inducers, including insulin, dexamethasone, isobutylmethylxantine (IBMX), indomethacin, and rosiglitazone, showed no significant effect on the adipogenic differentiation of BUSCs, efficient differentiation was achieved in the presence of a fatty acid cocktail. Furthermore, we explored methods for the delivery of BUSCs. Differentiated cells were delivered either encapsulated in GelMA hydrogel or populated on the surface of GelMA microparticles (MPs) as the adipose component of cultivated meat. Our findings reveal that after adipogenic induction, the lipid production per cell was comparable when cultured either within hydrogel or on MPs. However, GelMA-MPs supported better cell growth compared to hydrogel encapsulation. Consequently, the overall lipid production is higher when BUSCs are delivered via GelMA-MPs rather than encapsulation. This study not only systematically evaluated the impact of common adipogenic inducers on BUSCs, but also identified GelMA-MPs as a promising carrier for delivering bovine adipocytes for cultivated meat production.

Smart proteins as a new paradigm for meeting dietary protein sufficiency of India: a critical review on the safety and sustainability of different protein sources

India, a global leader in agriculture, faces sustainability challenges in feeding its population. Although primarily a vegetarian population, the consumption of animal derived proteins has tremendously increased in recent years. Excessive dependency on animal proteins is not environmentally sustainable, necessitating the identification of alternative smart proteins. Smart proteins are environmentally benign and mimic the properties of animal proteins (dairy, egg and meat) and are derived from plant proteins, microbial fermentation, insects and cell culture meat (CCM) processes. This review critically evaluates the technological, safety, and sustainability challenges involved in production of smart proteins and their consumer acceptance from Indian context. Under current circumstances, plant-based proteins are most favorable; however, limited land availability and impending climate change makes them unsustainable in the long run. CCM is unaffordable with high input costs limiting its commercialization in near future. Microbial-derived proteins could be the most sustainable option for future owing to higher productivity and ability to grow on low-cost substrates. A circular economy approach integrating agri-horti waste valorization and C1 substrate synthesis with microbial biomass production offer economic viability. Considering the use of novel additives and processing techniques, evaluation of safety, allergenicity, and bioavailability of smart protein products is necessary before large-scale adoption.

Animal-derived free hydrolysate in animal cell culture: Current research and application advances

Fetal bovine serum (FBS) plays a crucial role in the composition of animal cell culture medium. However, conventional serum-based medium face numerous challenges. The use of animal-derived free hydrolysate (ADFH) has garnered significant attention in research and applications as a viable alternative to FBS-containing medium in animal cell culture. This article provides a comprehensive overview of the effects, mechanisms of action, and applications of ADFH in animal cell culture. ADFH serves as an effective substitute for FBS-containing medium, enhancing various cellular processes, including cell proliferation, viability, protein synthesis, production, survival, and stability. Several mechanisms of action for ADFH have been elucidated through scientific investigations, such as nutrient provision, activation of signaling pathways, regulation of protein synthesis and folding, protection against oxidative damage and apoptosis, as well as cell cycle regulation. Researches and applications of ADFH represent a promising approach to overcoming the limitations of FBS-containing medium and advancing the field of animal cell culture. This review provides a theoretical foundation for promoting the development of sustainable and alternative hydrolysates, as well as the continued progress of animal cell culture.

Cultivated meat manufacturing: Technology, trends, and challenges

The growing world population, public awareness of animal welfare, environmental impacts and changes in meat consumption leads to the search for novel approaches to food production. Novel foods include products with a new or specifically modified molecular structure, foods made from microorganisms, fungi, algae or insects, as well as from animal cell or tissue cultures. The latter approach is known by various names: "clean meat", "in vitro meat" and "cell-cultured" or "(cell-)cultivated meat". Here, cells isolated from agronomically important species are expanded ex vivo to produce cell biomass used in unstructured meat or to grow and differentiate cells on scaffolds to produce structured meat analogues. Despite the fast-growing field and high financial interest from investors and governments, cultivated meat production still faces challenges ranging from cell source choice, affordable expansion, use of cruelty-free and food-grade media, regulatory issues and consumer acceptance. This overview discusses the above challenges and possible solutions and strategies in the production of cultivated meat. The review integrates multifaceted historical, social, and technological insights of the field, and provides both an engaging comprehensive introduction for general interested and a robust perspective for experts.

Mimicking Wagyu beef fat in cultured meat: Progress in edible bovine adipose tissue production with controllable fatty acid composition

Since the current process of livestock meat production has considerable effects on the global environment, leading to high emissions of greenhouse gases, cultured meat has recently attracted attention as a suitable alternative way to acquire animal proteins. However, while most published studies on cell-cultured meat have focused on muscle tissue culture, fat production which is an important component of the process has often been neglected from this technology, even though it can enhance the meat's final taste, aroma, tenderness, texture, and palatability. In this study, we focused on bovine muscle reconstruction by monitoring and optimizing the possible expansion rate of isolated primary bovine adipose stem cells and their adipogenesis differentiation to be fully edible for cultured meat application. After approximatively 100 days of serial passages, the bovine adipose-derived stem cells, isolated from muscle tissue, underwent 57 ​± ​5 doublings in the edible cell culture medium condition. This implies that by cultivating and amplifying them, a minimum of 2.9 ​× ​10²² ​cells can be obtained from around 10 ​g of fat. It was discovered that these cells retain their adipogenesis differentiation ability for at least 12 passages. Moreover, the final lipid composition could be controlled by adjusting the fatty acid composition of the culture medium during the differentiation process, resulting in organoleptic features similar to those of real fat from muscle. This was especially so for the cis isomer oleic acid percentage, an important part of high-grade Japanese Wagyu meat. These characteristics of the primary bovine adipose-derived stem cell proliferation and adipogenesis differentiation provide valuable insights for the in vitro production of meat alternatives.