Phytanic acid stimulates glucose uptake in a model of skeletal muscles, the primary porcine myotubes

BACKGROUND: Phytanic acid (PA) is a chlorophyll metabolite with potentials in regulating glucose metabolism, as it is a natural ligand of the peroxisome proliferator-activated receptor (PPAR) that is known to regulate hepatic glucose homeostasis. This study aimed to establish primary porcine myotubes as a model for measuring glucose uptake and glycogen synthesis, and to examine the impact of physiological amounts of PA on glucose uptake and glycogen synthesis either alone or in combination with insulin. METHODS: Porcine satellite cells were cultured into differentiated myotubes and tritiated 2-deoxyglucose (2-DOG) was used to measure glucose uptake, in relation to PA and 2-DOG exposure times and also in relation to PA and insulin concentrations. The MIXED procedure model of SAS was used for statistical analysis of data. RESULTS: PA increased glucose uptake by approximately 35%, and the presence of insulin further increased the uptake, but this further increase in uptake was non- additive and less pronounced at high insulin concentrations. There was no effect of PA alone on glycogen synthesis, while the insulin stimulation of glycogen was increased by 20% in the presence of PA. PA neither stimulated glucose uptake nor glycogen synthesis in insulin-resistant myotubes generated by excess glucose exposure. CONCLUSIONS: Primary porcine myotubes were established as a model of skeletal muscles for measuring glucose uptake and glycogen synthesis, and we showed that PA can play a role in stimulating glucose uptake at no or inadequate insulin concentrations

Milk, Meat, and Fish From the Petri Dish—Which Attributes Would Make Cultured Proteins (Un)attractive and for Whom? Results From a Nordic Survey

Cultured meat, fish, or dairy produced in vitro are discussed as one of the most substantial disruptions the food sector might encounter in the coming decades. These cultured proteins are proposed as a potential solution to the detrimental effects industrial food farming and fishing have on the environment and animal welfare as they would allow people to continue consuming meat, fish, or dairy products while at the same time substantially reducing the burden for the planet. For most people, however, this technology is still unknown, and it is largely unclear how they position themselves toward it. This paper presents the results of a representative survey (N = 3,864) in three Nordic countries (Norway, Denmark, and Finland). After briefly introducing the technological background, respondents spontaneously assessed their general attitude toward cultured proteins, their willingness to try them, and the likelihood that changes in 24 features of cultured protein would improve the respondents' attitude toward cultured protein products. The results showed that people in the studied countries have a neutral to a slightly positive view of cultured protein products. More familiarity seems to improve acceptance. Males, younger people, and vegans/vegetarians are particularly positive. The anticipated attitude change profiles showed that meat-eating identity, social norms, environmental concern, and country yielded the clearest profile differences, whereas health identity, age, innovativeness, income, education, and gender have smaller effects. People on a vegan or vegetarian diet cared less about most of the positive and negative aspects of cultured proteins compared to meat-eaters, with the exception of environmental and ethical aspects.Peer reviewe

A Functional Difficulty and Functional Pain Instrument for Hip and Knee Osteoarthritis

Introduction: The objectives of this study were to develop a functional outcome instrument for hip and knee osteoarthritis research (OA-FUNCTION-CAT) using item response theory (IRT) and computer adaptive test (CAT) methods and to assess its psychometric performance compared to the current standard in the field. Methods: We conducted an extensive literature review, focus groups, and cognitive testing to guide the construction of an item bank consisting of 125 functional activities commonly affected by hip and knee osteoarthritis. We recruited a convenience sample of 328 adults with confirmed hip and/or knee osteoarthritis. Subjects reported their degree of functional difficulty and functional pain in performing each activity in the item bank and completed the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Confirmatory factor analyses were conducted to assess scale uni-dimensionality, and IRT methods were used to calibrate the items and examine the fit of the data. We assessed the performance of OA-FUNCTION-CATs of different lengths relative to the full item bank and WOMAC using CAT simulation analyses. Results: Confirmatory factor analyses revealed distinct functional difficulty and functional pain domains. Descriptive statistics for scores from 5-, 10-, and 15-item CATs were similar to those for the full item bank. The 10-item OA-FUNCTION-CAT scales demonstrated a high degree of accuracy compared with the item bank (r = 0.96 and 0.89, respectively). Compared to the WOMAC, both scales covered a broader score range and demonstrated a higher degree of precision at the ceiling and reliability across the range of scores. Conclusions: The OA-FUNCTION-CAT provided superior reliability throughout the score range and improved breadth and precision at the ceiling compared with the WOMAC. Further research is needed to assess whether these improvements carry over into superior ability to measure change

Women in STEM Becoming Independent: Our Shared Motivation and Enthusiasm Are Our Driving Force

This year at JEM, we are highlighting women in science by sharing their stories and amplifying their voices. In this Viewpoint, we hear from a cross section of women, across multiple research fields, discussing their science and the process of setting up a lab as an independent researcher

Naringenin and falcarinol stimulate glucose uptake and TBC1D1 phosphorylation in porcine myotube cultures

Abstract: Insulin resistance in muscles is a major problem associated with Type 2 diabetes. Bioactive compounds of plant origin have long been known for possessing anti-diabetic properties. We have studied the effect of the bioactive compounds naringenin (dihydroflavonol) and falcarinol (polyacetylene) on glucose uptake (GU) in normal and insulin resistant primary porcine myotubes, in the presence and absence of insulin to identify signaling pathways mediating their effects on GU. The dependence on glucose transporter type 4 (Glut4) activity, insulin signaling and AMP-activated protein kinase (AMPK)-signaling was studied by using the Glut4 inhibitor indinavir, the phosphatidyl inositol-3 kinase (PI3K) and p38 mitogen activated protein kinase (MAPK) inhibitor wortmannin, and the AMPK inhibitor dorsomorphin (DM), respectively. Naringenin and falcarinol stimulated GU was attenuated in the presence of indinavir and wortmannin, indicating a dependence on Glut4 activity as well as PI3K and/or p38MAPK activity. By contrast, DM diminished GU induced by naringenin only, indicating that falcarinol-stimulated GU was independent of AMPK activity. Finally, we show that naringenin and falcarinol enhance phosphorylation of TBC1D1 suggesting that these compounds enhance translocation of Glut4 containing vesicles and thereby GU via a TBC1D1-dependent mechanism

Life cycle assessment of culture media with alternative compositions for cultured meat production

Abstract Purpose Cultured meat is produced by cultivating animal cells in a bioreactor in a culture medium that provides nutrients and growth factors. Among other animal sera, fetal bovine serum (FBS) has traditionally been the most common used in the culture medium of mammalian cell cultures, i.e., 10% FBS medium that contains 10% FBS and 90% DMEM/F12 (v/v). As the aim of cultured meat is to replace livestock production, animal component-free culture media needs to be developed. Methods We analyzed the environmental impact of replacing the 10% FBS culture medium with serum substitutes, i.e., growth factors, Essential 8™, protein hydrolysates from egg-white, eggshell membrane, poultry residues, pork plasma, and pea concentrate, and Tri-basal 2.0+ITS medium that contains fbroblast growth factor (FGF-2), fetuin, bovine serum albumin (BSA), and insulin transferrin selenium (ITS). Life cycle assessment with a cradle-to-gate approach was used to quantify global warming potential, freshwater and marine eutrophication, terrestrial acidifcation, land use, water consumption, fossil resource scarcity, particulate matter formation, cumulative energy demand, and ozone formation of preparing 1-L culture medium. Sensitivity analysis was conducted to examine the impact changes under various production conditions including variations in the impact allocation strategy, production location, and energy sourcing. Results and discussion The 2% FBS medium (2% FBS, 96% DMEM/F12, and 2% growth factors (v/v)) reduced all environmental impacts where marine eutrophication had the highest reduction (77%), while land use was the least afected with a reduction of 6%. The Tri-basal 2.0+ITS and protein hydrolysates media reduced most of the analyzed environmental impacts. Protein hydrolysates from egg-white had the lowest environmental impacts reducing 81% global warming potential, 28% water consumption, 59% fossil scarcity, 87% eutrophying emissions, 91% terrestrial acidifcation, 82% particulate matter, and 70% ozone formation, compared to FBS-containing medium. Land use and energy demand were reduced the most by 17 and 37%, respectively, when the 10% FBS medium was replaced with the Tri-basal 2.0+ITS medium. Conclusions Changing the input of FBS in culture media from 10 to 2% (v/v) reduced all studied environmental impacts. Further reductions were achieved when FBS was totally replaced by basal media DMEM/F12, Essential 8™, protein hydrolysates, and recombinant growth factors. Land use was the least reduced, as it was driven by starch extraction to produce glucose for the DMEM/ F12 basal medium. Culture medium with protein hydrolysates from egg-white achieved the highest impact reductions compared with the FBS-containing medium.publishedVersio

Critical review of cultivated meat from a Nordic perspective

Background: Cultivated meat is a novel technology with the potential to partly substitute conventional meat in the future. Production of cultivated meat is based on biotechnology for tissue engineering, up-scaling of cell cultures and stem-cell differentiation, providing the basis for large-scale proliferation of the parent cell and subsequent differentiation into primitive skeletal muscle structures known from conventional meat. Development of cultivated meat is considered a socio-technological challenge including a variety of technical, sustainability, ethical, and consumer acceptance issues. Scope and approach: As the Nordic countries share common history and roots of food culture, cultivated meat will be introduced into a socio-cultural context with established food traditions. This review summarizes the current knowledge and activities on the development of cultivated meat in the Nordic countries and considers this novel food product in a specific socio-cultural context. Key findings and conclusions: The production of cultivated meat in the Nordic countries, must encompass solutions that are accepted by the typical Nordic consumer. In general, this favors solutions for cell culturing based on non-GMO cells and locally accessible raw material for cell medias and scaffolding. From the perspective of the Nordic countries, this will improve the environmental, societal, and ethical context of cultivated meat.publishedVersio

Post-mortem activity of the glycogen debranching enzyme and change in the glycogen pools in porcine M. longissimus dorsi from carriers and non-carriers of the RN− gene

Glycogen debranching enzyme (GDE) is together with glycogen phosphorylase responsible for the degradation of glycogen. The present study compares the post-mortem activity of GDE and breakdown of the glycogen pools in M. longissimus dorsi of RN- carrier pigs and in wild type animals. The activity of GDE (n=14) and pH (n=20) was measured 0.5, 3, 5, 24 and 48 h post-mortem. The change in pro-glycogen and in macro-glycogen content (n=20) was followed until 216 h post-mortem and the transcription level of GDE, glycogenin and glycogen synthase m-RNA (n=19) were measured 0.5 h post-mortem. Both the activity of GDE and the transcription level of GDE were found to be similar in RN- carriers and wild type animals shortly after slaughter. However, the activity declined faster in wild type animals compared with RN- carriers with increasing time post-mortem. The contents of both pro-glycogen and macro-glycogen were higher in RN- carriers compared with wild type animals, and further, the proportion of macro-glycogen was higher in RN- carriers compared with wild type animals. During the post-mortem period, only degradation of pro-glycogen was observed in both genotypes. The decrease in pH was faster and the ultimate pH lower in RN- carriers than in wild type animals. It was suggested that the higher GDE activity in the late phase of the post-mortem period in muscles from RN- carriers renders the extended pH decrease in these muscles