Tissue Lipid Content Research Articles

P0402 Preoperative body composition parameters are associated with postoperative complications and endoscopic postoperative recurrence in patients with Crohn’s disease

Abstract Background Alterations in body composition are common among patients with Crohn’s disease (CD) and may represent a modifiable risk factor for dismal postoperative outcomes. This study aimed to investigate the association of preoperative body composition with postoperative complications and endoscopic postoperative recurrence (ePOR) in CD patients following ileocolic (re-)resection (ICR). Methods CD patients (≥16 years) scheduled for ICR with a preoperative CT or MRI scan (<12 months prior to ICR) were identified from an ongoing prospective, multicenter cohort study. Cross-sectional area normalized for body height (i.e. index) and lipid content (i.e. radiation attenuation on CT or signal intensity on MRI) of sketelal muscle (SM), subcutaneous adipose (SAT), and visceral adipose tissue (VAT) were analyzed at L3 level. Cut-offs were based on sex-specific tertiles. The primary outcome was postoperative complications (Clavien-Dindo grade I-IV) within 30 days. Secondary outcomes were moderate-to-severe complications (Clavien-Dindo grade ≥II), infectious complications (intra- or extra-abdominal), and ePOR (modified Rutgeerts’ score ≥i2b) at six months postoperatively. Multivariable logistic regression was performed to assess the association of preoperative body composition with study outcomes. Results In total, 227 patients were included. Preoperative characteristiscs and postoperative outcomes are shown in Table 1. Median interval from preoperative imaging to ICR was 2.3 months (IQR 1.1–4.6). High lipid content of SM (i.e. myosteatosis) was associated with postoperative complications (aOR 2.51; 95%CI 1.21–5.22), moderate-to-severe complications (aOR 2.34; 95%CI 1.13–4.85), and infectious complications (aOR 2.20; 95%CI 1.01–4.80) (Figure 1). Low VAT-index was protective against postoperative complications (aOR 0.17; 95%CI 0.05–0.58). Low lipid content of VAT (aOR 3.98; 95%CI 1.15–13.78) and a high SAT-index (aOR 3.38; 95%CI 1.12–10.15) were associated with infectious complications. High SM-index was associated with ePOR (aOR 2.51; 95%CI 1.09–5.77). Preoperative body mass index (BMI) showed no association with study outcomes in uni- and multivariable analyses. Conclusion Preoperative myosteatosis on abdominal imaging is consistently associated with postoperative complications in patients with CD following ICR. Low VAT-index was identified as protective factor for postoperative complications, while low lipid content of VAT and a high SAT-index were associated with infectious complications. Surprisingly, high SM increased the risk of ePOR. Future research should identify strategies for preoperative improvement of body composition, rather than relying solely on BMI, and investigate if these improvements correlate with better postoperative outcomes.

Pyrroloquinoline quinone-loaded coaxial nanofibers prevent oxidative stress after spinal cord injury.

Oxidative stress plays a major role in the secondary injury of the spinal cord tissue due to the high lipid content of nervous tissue. In the present study, coaxial nanofibers were loaded with the natural antioxidant pyrroloquinoline quinone (PQQ) and used as an implantable drug-delivery system and a scaffold post-SCI. The obtained data show that the concentration of NO and the activity of inducible nitric oxide synthase (iNOS) were significantly (P < 0.05) increased in the spinal cord injury (SCI) group. These levels were significantly decreased following treatment with nanofibers/PQQ. Implantation of nanofibers/PQQ resulted in a significant (P < 0.05) drop in the level of malondialdehyde (MDA) compared to the SCI group. The application of nanofibers loaded with PQQ after SCI caused a significant (P < 0.05) elevation of superoxide dismutase (SOD) and catalase (CAT) activity in the spinal cord tissue. The present work shows the protective role of coaxial nanofibers loaded with PQQ against oxidative stress in spinal cord injury. The reversal of oxidative stress with PQQ can lead to better outcomes following spinal cord injury.

Cinnamon powder intake enhances the effect of caloric restriction on white adipose tissue in male rats.

Caloric Restriction (CR) and cinnamon promote several benefits, including the modulation of lipid metabolism and body fat mass. We hypothesize that cinnamon may act as a mimetic of restriction or enhance the effects of caloric restriction on adipose tissue. Adult male Wistar rats were divided into Control (CT, n = 8) and Cinnamon (CIN, n = 7), with free access to standard chow; Calorie Restriction (CR, n = 8) and Calorie Restriction with Cinnamon (CIN-CR, n = 7), subjected to a 30% reduction in food intake compared to the average consumption of CT rats. Both CIN groups received 50mg cinnamon powder (Cinnamomun verum) per kg body mass, by gavage, over 6 weeks. Cinnamon treatment did not alter food intake under either ad libitum or caloric restriction conditions. The CR and CIN-CR groups exhibit lower body mass. Basal glycemia, lipid profile, and triglyceride-glycemic index were similar between groups. The combination of both interventions induced lower visceral white adipose tissue (WAT) mass, and smaller adipocyte diameter in the visceral and subcutaneous WAT compartments, accompanied by reduced expression of genes related to lipid metabolism (Acaca, Fasn, Cd36, Srebf1c), suggesting decreased lipid synthesis. Histological analyses identified a browning phenotype in the CR, CIN, and CIN-CR groups, positive for UCP1 immunostaining. The CR and CIN-CR groups showed lower Atg7 expression, and CIN-CR animals expressed increased levels of Lamp2, suggesting modulation of autophagy. Brown adipose tissue mass and lipid content were not influenced by any intervention. These findings suggest that cinnamon may enhance the effects of caloric restriction in promoting adipocyte metabolic health.

Knockout of the Muscle-Specific E3 Ligase MuRF1 Affects Liver Lipid Metabolism upon Dexamethasone Treatment in Mice.

In order to preserve muscle mass during catabolic states, investigators are actively searching for a specific inhibitor of MuRF1, the only known E3 ligase that can target muscle contractile proteins for their degradation. However, what would be the consequences of such inhibitors on other organs, both in the short and long term? Indeed, skeletal muscles can provide amino acids for liver gluconeogenesis, which is a crucial adaptation for maintaining glucose homeostasis upon elevated energy demands (e.g., during prolonged starvation). Comparing 3-month-old wild-type and MuRF1-KO mice, we measured tissue weights, liver glycogen, lipid and protein content, and liver biochemical composition using Fourier transform infrared (FTIR) spectrometry in control animals and in dexamethasone (Dex)-treated animals. Dex induces a catabolic situation with muscle atrophy and lipid deposits in the liver. In response to Dex treatment, liver glycogen, lipid, and protein content increased in wild type (WT) and MuRF1-KO mice. We found that MuRF1 deletion differentially affected organ weights, the liver of KO mice being hypertrophied upon Dex treatment when compared to WT mice. Upon Dex treatment, muscle mass was preserved in MuRF1-KO mice, and by contrast, liver lipid content increased more in these animals than in WT mice. PLS-DA analysis of FTIR showed that the levels of 13 markers were significantly altered in KO vs WT mice, witnessing profound alterations of lipid, protein, and glycogen content in the liver due to the absence of MuRF1. Using Nile red and oil red lipid staining, we also found that both membrane-linked lipids and intracellular lipid droplets were altered due to the absence of MuRF1. Altogether, it seems that when the liver is deprived of the possibility of obtaining amino acids from muscle upon Dex treatment, there is a concomitant increase in tissue weight and anabolic activity.

Fatty Acid Content and Lipid Nutritional Indexes in the Antarctic Krill Euphausia superba Collected from Three Regions of the Atlantic Sector of Antarctica.

The total lipid (TL) and fatty acid (FA) contents in tissues and body segments were studied in adult Antarctic krill (Euphausia superba) caught in three regions of the Atlantic sector of Antarctica with different environmental conditions. Significant differences in lipid and FA status of the Antarctic krill tissues and body segments were observed in the regions. Main metabolic indices indicating quality of lipids showed that E.superba has a high nutritional value. In particular, lipids are highly unsaturated in the species and ratios of physiologically significant and essential FAs are favorable to human health. This was assumed to be a distinctive biochemical characteristic of the species. Data from the study can be used to form a scientifically based approach to further technological processing of raw krill and targeted extraction of certain substances and components of a lipid nature.

Effect of a multidisciplinary lifestyle intervention on body composition in people with osteoarthritis: Secondary analysis of the “Plants for Joints” randomized controlled trial

ObjectiveThe Plants for Joints (PFJ) intervention significantly improved pain, stiffness, and physical function, and metabolic outcomes, in people with metabolic syndrome-associated osteoarthritis (MSOA). This secondary analysis investigated its effects on body composition. MethodIn the randomized PFJ study, people with MSOA followed a 16-week intervention based on a whole-food plant-based diet, physical activity, and stress management, or usual care. For this secondary analysis, fat mass, muscle mass, and bone mineral density were measured using dual-energy X-ray absorptiometry (DEXA) for all participants. Additionally, in a subgroup (n ​= ​32), hepatocellular lipid (HCL) content and composition of visceral adipose tissue (VAT) were measured using magnetic resonance spectroscopy (MRS). An intention-to-treat analysis with a linear-mixed model adjusted for baseline values was used to analyse between-group differences. ResultsOf 66 people randomized, 64 (97%) completed the study. The PFJ group experienced significant weight loss (−5.2 ​kg; 95% CI –6.9, −3.6) compared to controls, primarily from fat mass reduction (−3.9 ​kg; 95% CI –5.3 to −2.5). No significant differences were found in lean mass, muscle strength, or bone mineral density between groups. In the subgroup who underwent MRI scans, the PFJ group had a greater reduction in HCL (−6.5%; 95% CI –9.9, 3.0) compared to controls, with no observed differences in VAT composition. ConclusionThe PFJ multidisciplinary intervention positively impacted clinical and metabolic outcomes, and appears to significantly reduce body fat, including liver fat, while preserving muscle mass and strength.

Characterization of the Bioavailability of Per- and Polyfluoroalkyl Substances in Farmland Soils and the Factors Impacting Their Translocation to Edible Plant Tissues.

In this study, various crops and farmland soils were collected from the Fen-Wei Plain, China, to investigate the bioavailability of perfluoroalkyl substances (PFAS), their accumulation in edible plant tissues, and the factors impacting their accumulation. PFAS were frequently detected in all of the crops, with total concentrations ranging from 0.61 to 35.8 ng/g. The results of sequential extractions with water, basic methanol, and acidic methanol indicate that water extraction enables to characterize the bioavailability of PFAS in soil to edible plant tissues more accurately, especially for the shorter-chain homologues. The bioavailability of PFAS was remarkably enhanced in the rhizosphere (RS) soil, with the strongest effect observed for leafy vegetables. The water-extracted Σ16PFAS in RS soil was strongly correlated with the content of dissolved organic carbon in the soil. Tannins and lignin, identified as the main components of plant root exudates by Fourier transform-ion cyclotron resonance mass spectrometry, were found to enhance the bioavailability of PFAS significantly. Redundancy analysis provided strong evidence that the lipid and protein contents in edible plant tissues play important roles in the accumulation of short- and long-chain PFAS, respectively. Additionally, the high water demand of these tissues during the growth stage greatly facilitated the translocation of PFAS, particularly for the short-chain homologues and perfluorooctanoic acid.

Brown adipose tissue facilitates the fever response following infection with Salmonella enterica serovar Typhimurium in mice

Brown adipose tissue (BAT) combusts lipids and glucose to generate heat. Via this process of nonshivering thermogenesis, BAT plays a pivotal role in thermoregulation in cold environments, but its contribution to immune-induced fever is less clear. Male APOE∗3-Leiden.CETP mice, a well-established model for human-like lipoprotein metabolism, and wild-type mice were given an intraperitoneal injection of Salmonella enterica serovar Typhimurium (S.tm). Energy expenditure and substrate utilization, plasma lipid levels, fatty acid (FA) uptake by adipose tissues, and lipid content and thermogenic markers in adipose tissues were examined. S.tm infection led to a set of characteristic symptoms, including elevated body temperature and decreased body weight. Whole-body energy expenditure was significantly decreased 72 h postinfection, but fat oxidation was increased and accompanied by a substantial reduction in plasma triglyceride (TG) levels as demonstrated in APOE∗3-Leiden.CETP mice. S.tm infection strongly increased uptake of FAs from TG-rich lipoproteins by BAT, which showed a positive correlation with body temperature in infected mice. Upon histological examination of BAT from wild-type or APOE∗3-Leiden.CETP mice, elevated levels of tyrosine hydroxylase were observed, indicative of stimulated sympathetic activity. In addition, the gene expression profile was consistent with more adrenergic stimulation, while lipid content was reduced. Furthermore, browning of white adipose tissue was observed, evidenced by a modest increase in TG-derived FA uptake, the presence of multilocular cells, and induction of uncoupling protein 1 expression. We proposed that BAT, or thermogenic adipose tissue in general, is involved in the maintenance of elevated body temperature upon invasive bacterial infection.

GROWTH PERFORMANCE AND HEMATOGICAL RESPONSES OF LABEO ROHITA FINGERLINGS TO DIETARY CITRULLUS LANATUS SEED MEAL AS SUBSTITUTE OF SOYBEAN MEAL

A 50 day feeding trial was conducted to determine the effects of replacing Soybean meal (SBM) protein with watermelon seed meal (WSM) on growth, feed utilization of Labeo rohita. Four isonitrogenous (30%) diets were applied in four treatment groups designed as WSM0, WSM15, WSM30 and WSM45, Where 0%, 15%, 30% and 45% of SBM protein were substituted by WSM respectively. Significantly higher mean final weight (g), weight gain (%) and specific growth rate was recorded in all treatments. Consequently, significantly lower feed conversion ratio (FCR) was found in all treatments. Moreover, protein content and lipid content of fish muscle tissues were significantly in higher in all treatments. Hemoglobin, Red blood cells and White blood cells were significantly higher in all treatments. Therefore, the results suggest that WSM could replace up to 45% replacement of SBM protein in diets of Labeo rohita without comprising growth performance.

Non-invasive optoacoustic imaging of dermal microcirculatory revascularization in diet-induced obese mice undergoing exercise intervention

Microcirculatory dysfunction has been observed in the dermal white adipose tissue (dWAT) and subcutaneous white adipose tissue (scWAT) of obese humans and has been proposed as an early prediction marker for cardio-metabolic disease progression. In-vivo visualization and longitudinal monitoring of microvascular remodeling in these tissues remains challenging. We compare the performance of two optoacoustic imaging methods, i.e. multi-spectral optoacoustic tomography (MSOT) and raster-scanning optoacoustic mesoscopy (RSOM) in visualizing lipid and hemoglobin contrast in scWAT and dWAT in a mouse model of diet-induced obesity (DIO) undergoing voluntary wheel running intervention for 32 weeks. MSOT visualized lipid and hemoglobin contrast in murine fat depots in a quantitative manner even at early stages of DIO. We show for the first time to our knowledge that RSOM allows precise visualization of the dWAT microvasculature and provides quantitative readouts of skin layer thickness and vascular density in dWAT and dermis. Combination of MSOT and RSOM resolved exercise-induced morphological changes in microvasculature density, tissue oxygen saturation, lipid and blood volume content in dWAT and scWAT. The combination of MSOT and RSOM may allow precise monitoring of microcirculatory dysfunction and intervention response in dWAT and scWAT in a mouse model for DIO. Our findings have laid out the foundation for future clinical studies using optoacoustic-derived vascular readouts from adipose tissues as a biomarker for monitoring microcirculatory function in metabolic disease.

Tartaric acid ameliorates experimental non-alcoholic fatty liver disease by activating the AMP-activated protein kinase signaling pathway

Tartaric acid (TA) has been shown beneficial effects on blood pressure and lipid levels. However, its effect on non-alcoholic fatty liver disease (NAFLD) remains unknown. This study aimed to investigate the role of TA in experimental NAFLD. Mice were fed a Western diet for 8 weeks, followed by administration of TA or a vehicle for an additional 12 weeks while continuing on the Western diet. Blood biochemistry including transaminases and glucose tolerance test and liver tissue RNA sequencing (RNA-seq), lipid content, and histology were investigated. The HepG2 cell line was used to explore the mechanism by which TA regulates lipid metabolism. We found that TA significantly improved weight gain, insulin resistance, hepatic steatosis, inflammation and fibrosis in Western diet-fed mice. By comparing gene expression differences, we found that TA affects pathways related to lipid metabolism, inflammatory response, and fibrosis. Furthermore, TA effectively reduced oleic acid-induced lipid accumulation in HepG2 cells and downregulated the genes associated with fatty acid synthesis, which were enriched in the AMP-activated protein kinase (AMPK) signaling pathway. TA also enhanced the phosphorylation of AMPK which could be reverted by the AMPK inhibitor Compound C in HepG2 cells. Our study suggests that TA improves experimental NAFLD by activating the AMPK signaling pathway. These findings indicate that TA may serve as a potential therapy for the human NAFLD.

Glycyrrhizinic Acid and Phosphatidylcholine Combination as a Preventive Therapy for Experimental Murine Non-Alcoholic Steatohepatitis

Non-alcoholic metabolic-associated steatohepatitis (MASH) is a condition characterized by increasingly high prevalence and incidence, and also represents an important unmet medical need when it comes to effective pharmacotherapy. In this work, we aimed to explore the therapeutic possibilities of the synergistic combined use of glycyrrhizinic acid (GA) and phosphatidylcholine (PC) to prevent experimental MASH. Adult C57Bl/6 mice were used to model dietary/toxic MASH and treated orally by either GA (34.3 mg/kg/d) or a GA + PC combination (34.3 + 158.1 mg/kg/d) for 3 months. Animal locomotion, behaviour, short-term memory, physical performance, neuromuscular joint function, blood biochemistry, and oxidative stress marker levels were evaluated, followed by histological examination of the liver, skeletal muscle and sciatic nerve with tissue ammonia and lipid content determination. Real-time polymerase chain reaction was used to measure the relative expression of several pathogenetic transcript markers. GA and PC showed moderate additive synergism in their anti-inflammatory, antioxidant, hypoammonaemic, hypoglycaemic, and pro-cognitive activities. Differential effects of the agents were seen in regard to anxiety- and depression-like behaviour as well as gene expression. Our results indicate partial pharmacological synergism between GA and PC and validate further research of its potential clinical applications.

Bioconcentration of polycyclic aromatic hydrocarbons in different tissues of zebrafish (Danio rerio) investigated with PBTK model.

Due to the lipophilicity, polycyclic aromatic hydrocarbons (PAHs) are easily accumulated in fish. However, the research on PAH bioaccumulation process in different fish tissues and the relevant effect mechanisms are still deficient. The bioconcentration of PAHs (phenanthrene, anthracene, fluoranthene, and pyrene) in different zebrafish tissues (skin, fish muscle, gill, digestive tract, liver, gonad, and residual) was studied. It was found that there was a difference in the PAH concentrations in different zebrafish tissues. Compared with other tissues, the PAH concentration was highest in the skin and lowest in the fish muscle. For example, the steady-state concentration of phenanthrene in the skin was nearly five times higher than that in the muscle. PAH distribution was related with the lipid contents in different zebrafish tissues; however, the correlation was not significant (p > 0.05), indicating that the lipid content was not the determining factor for the PAH distribution. The distribution was also affected by the bioconcentration kinetics of PAHs in different zebrafish tissues, and the PAH hydrophobic properties. In addition, the physiological based toxicokinetic (PBTK) model showed good performance in predicting PAH internal concentrations, and it may be used to predict the concentrations of PAHs in different fish tissues in future.

Effects of Dietary Vitamin E Supplementation on Growth Performance, Body Composition of Golden Trevally, Gnathanodon speciosus

Golden trevally, Gnathanodon speciosus is a new candidate for aquaculture in Viet Nam. This species has rapid growth, high market value, delectable flavour. Finding solutions to enhance production by promoting growth is necessary in golden trevally aquaculture. Vitamin E is one of the feed supplements which has proven the benefit on other aquaculture species but there has not been any study on golden trevally. Therefore, this experiment was designed to test the effect of vitamin E on the golden trevally, Gnathanodon speciosus. Three levels of vitamin E (50, 100, and 200 mg kg-1 diet) were supplemented to the basal diet (control diet). There was 4 diet treatments and 3 replicates for each treatment. The golden trevally (initial weight 7.63 g ± 0.13 (SEM)) were fed experimental diets for eight weeks. The growth performance and protein and lipid content of tissues were evaluated. At the end of the feeding trial (week 8), the presence of vitamin E in a fish's diet resulted in a significant increase in its growth rate (P &lt; 0.05). The survival rate of fish fed diets containing 50 - 200 mg of vitamin E was substantially higher than that of control fish. In addition, protein and lipid levels in the flesh of golden trevally increased significantly as vitamin levels in their diets rose. For optimal growth and survival, it is recommended to supplement the diet of golden trevally with at least 50 mg of vitamin E per kilogramme. In conclusion, supplementing the diet with vitamin E improves growth, survival, and body composition in juveniles of this species. As this experiment is the first study on the effects of vitamin E on golden trevally, it is worthy of investigation.

Intra-specific correlations between fatty acids and morphological traits are consistent across fish species

We explored intraspecific relationships between biochemical and morphometric traits among sixteen fish species from the Canadian waters of the Laurentian Great Lakes. We focused on hypotheses linking two morphometric descriptors (fish length and condition factor, CF, the latter derived from species-specific allometric-growth equations) to lipid content and polyunsaturated fatty acid (PUFA) composition of dorsal muscle tissue. Each population from each of the lakes was assumed to display different relationships. All correlations were better represented by linear than non-linear relationships. Interspecific and among lakes differences accounted for most of the registered variability of fatty acid (FA) composition. Once these two covariates were parsed out, there was a discernible intraspecific coupling between fish length, CF, and fish biochemical traits, including positive correlations with muscle lipid and PUFA composition. The sign of the correlations was consistent among different populations, aligned with the theoretical expectations, and with interspecific trait correlations. However, for some species, correlations could be positive in one lake but negative in another, suggesting that local environmental variations could affect biochemical rates. We also found three trends associated with the rate at which different fatty acids accumulate in fish muscle tissue that are potentially related to food availability. These relationships between CF and FA composition provide a promising starting point to establish efficient, cost-effective, field-based estimates of essential FA descriptors. In this vein, we present a user-friendly application for the estimation of lipid content and PUFA composition, based solely on weight and length, that any angler and/or citizen-science participant can easily obtain.

Excessive exogenous cholesterol activating intestinal LXRα-ABCA1/G5/G8 signaling pathway can not reverse atherosclerosis in ApoE−/− mice

BackgroundThe long-term excessive intake of exogenous cholesterol can lead to abnormally elevated blood lipid levels and induce cardiovascular and cerebrovascular diseases. However, the influence and relevance of exogenous cholesterol on plasma cholesterol components were still unclear, and the influence on intestinal lipid metabolism targets needs to be further explored.MethodsIn vivo, the C57BL/6 + NF group and ApoE−/− + NF group mice were fed a normal specific pathogen-free (SPF) diet; the ApoE−/− + HF group mice were fed a high-cholesterol SPF diet. The plasma and jejunum tissue homogenate were obtained for non-targeted lipid metabolomics. The lipid droplets in tissues were observed by transmission electron microscope and oil red O staining. Jejunum tissue morphology was observed by HE staining. The kits were used to detect lipid content in plasma, tissues, intestinal contents, and cells. Western blot, RT-PCR, immunohistochemistry (IHC), and immunofluorescence (IF) were used to observe the key target of lipid metabolism. In vitro, the final concentration of cholesterol was 100 μmol/L in Caco-cells. Oil red O staining, western blot, RT-PCR and immunofluorescence (IF) were used to observe the changes of lipid metabolism. Finally, the influence of liver X receptor alpha (LXRα) on intestinal cholesterol metabolism was clarified by applying the LXRα inhibitor GSK2033 and siRNA targeting LXRα.ResultsThe aortic arch and intestinal villi of the two groups of ApoE−/− mice showed apparent lesions and lipid accumulation, and there were significant changes in a variety of lipids in the plasma and jejunum. Additionally, jejunum LXRα was markedly activated. High cholesterol can significantly activate LXRα in Caco-2 cells. After LXRα was inhibited, the protein level of ATP-binding cassette transporter A1/G5/G8 (ABCA1/G5/G8) decreased, and the quantity and volume of intracellular lipids soared.ConclusionIn a high-cholesterol environment, the intestine promotes the excretion of cholesterol from the cell through the LXRα-ABCA1/G5/G8 pathway, reduces the intestinal intake of a variety of exogenous cholesterol, and reduces the risk of AS.Graphical

Juvenile Dungeness crab foraging behavior and lipid composition is altered more by food quantity than seawater pH in a multi-stressor experiment

Increases in atmospheric, anthropogenic carbon are driving reductions in seawater pH, a process referred to as ocean acidification. Reduced seawater pH can influence behavior of marine animals, but little is currently known about how juvenile crustaceans will respond. We conducted lab experiments to improve our understanding of the consequences of pH exposure and food quantity on juvenile Dungeness crab (Metacarcinus magister, (Dana, 1852)) behavior and nutritional condition. To understand the foraging and pH sensing behavior of juvenile crab, and how this interacts with their nutritional status, we exposed recently settled second instar juveniles to either ambient pH or reduced pH for 42-d, crossed with either a ‘maintenance’- or low-quantity ‘challenge’ diet treatment. After the experimental exposure period, we introduced crab into foraging and sensing pH behavior experiments. In the foraging experiment, we placed crab in a behavior arena with unidirectional flow, where we measured the food discovery time and time allocation of activities in 300-s trials for all individual crab. Food quantity and pH exposure influenced both the speed with which juvenile crab identified and allocation of activities but there was no interactive effect of experimental factors. For our pH sensing experiment, we used a two-current flume plumbed with both ambient and reduced pH seawater. This flow-through flume provided a choice between the pH treatment waters and allowed us to measure the amount of time individuals spent on either side of the arena in 300-s trials. There was no effect of prior diet or pH exposure on the amount of time juvenile crab spent in either seawater pH condition. In addition to the behavior trials, we evaluated crab nutritional condition by quantifying the total lipid content of whole-body tissues and fatty acid profile composition of juvenile crab fed either the maintenance or low-quantity diet during the experimental pH exposure period. The proportional fatty acid profiles differed for crab based on their diet and pH exposure, with no interactive effects. However, we did not detect differences in the concentrations of key summary categories of fatty acids (e.g., saturated, monounsaturated, or polyunsaturated) based on pH exposure. Our results indicate that reduced food availability has a greater impact on juvenile Dungeness crab foraging behavior and nutritional condition than reduced seawater pH exposure representing the 0.3 pH unit decrease predicted by 2100.

GPCR in Adipose Tissue Function-Focus on Lipolysis.

Adipose tissue can be divided anatomically, histologically, and functionally into two major entities white and brown adipose tissues (WAT and BAT, respectively). WAT is the primary energy depot, storing most of the bioavailable triacylglycerol molecules of the body, whereas BAT is designed for dissipating energy in the form of heat, a process also known as non-shivering thermogenesis as a defense against a cold environment. Importantly, BAT-dependent energy dissipation directly correlates with cardiometabolic health and has been postulated as an intriguing target for anti-obesity therapies. In general, adipose tissue (AT) lipid content is defined by lipid uptake and lipogenesis on one side, and, on the other side, it is defined by the breakdown of lipids and the release of fatty acids by lipolysis. The equilibrium between lipogenesis and lipolysis is important for adipocyte and general metabolic homeostasis. Overloading adipocytes with lipids causes cell stress, leading to the recruitment of immune cells and adipose tissue inflammation, which can affect the whole organism (metaflammation). The most important consequence of energy and lipid overload is obesity and associated pathophysiologies, including insulin resistance, type 2 diabetes, and cardiovascular disease. The fate of lipolysis products (fatty acids and glycerol) largely differs between AT: WAT releases fatty acids into the blood to deliver energy to other tissues (e.g., muscle). Activation of BAT, instead, liberates fatty acids that are used within brown adipocyte mitochondria for thermogenesis. The enzymes involved in lipolysis are tightly regulated by the second messenger cyclic adenosine monophosphate (cAMP), which is activated or inhibited by G protein-coupled receptors (GPCRs) that interact with heterotrimeric G proteins (G proteins). Thus, GPCRs are the upstream regulators of the equilibrium between lipogenesis and lipolysis. Moreover, GPCRs are of special pharmacological interest because about one third of the approved drugs target GPCRs. Here, we will discuss the effects of some of most studied as well as "novel" GPCRs and their ligands. We will review different facets of in vitro, ex vivo, and in vivo studies, obtained with both pharmacological and genetic approaches. Finally, we will report some possible therapeutic strategies to treat obesity employing GPCRs as primary target.

An optimized method for Oil Red O staining with the salicylic acid ethanol solution

ABSTRACT Oil Red O (ORO) staining is a commonly used experimental technique to detect lipid content in cells or tissues. Freshly prepared ORO in 60% isopropanol is the most widely used method at present. However, isopropanol is volatile and harmful to the human body. It will also affect the interpretation of the results due to the formation of crystals and non-specific diffuse staining. In this paper, by screening and validation, we report a salicylic acid ethanol solution (containing 50% ethanol, 5%-10% salicylic acid) for the preparation of ORO solution, which has a better staining effect on lipid staining in cells and tissues, with a clean background and short dyeing time. What’s more, this ORO solution is non-toxic, convenient to prepare, and can be stored for a long time. Therefore, it is reliable, easy to operate, and can be widely popularized and applied in laboratories.

Supplementation with rumen-inert fat in the growing phase altered adipogenic gene expression and the size and number of adipocytes in Hanwoo steers.

We hypothesized that the provision of rumen-inert fat (RIF) to growing cattle (9 to 13 mo of age) would affect the expression of genes involved in lipid metabolism and thereby affect the size and number of adipocytes of steers slaughtered at 30 mo of age. Thirty steers with an average initial body weight (BW) of 239 ± 25 kg were allocated to six pens, balanced for BW and genetic merit for marbling, and assigned to one of two treatment groups: control (only basal diet) or test diet (basal diet with 200 g of RIF per day, on an as-fed basis) for 5 mo. Biopsy samples of longissimus lumborum (LM) muscle were then collected for analysis of fatty acid composition and gene expression. Both groups were then fed the same basal diets during the early and late fattening phases, without RIF, until slaughter (average shrunk BW = 759 kg). Supplementation with RIF increased the longissimus thoracis (LT) intramuscular fatty acid concentration at slaughter (P = 0.087) and numerically increased the quality grade score (P = 0.106). The LM intramuscular relative mRNA expression of genes such as PPARα, ZFP423 and SREBP1, FASN, SCD, FABP4, GPAT1, and DGAT2 were downregulated (P < 0.1) following RIF supplementation. Supplementation of RIF decreased (P < 0.1) diameter and concomitantly increased intramuscular adipocytes per viewing section at slaughter. This likely was caused by promotion of triacylglycerol hydrolysis during the growing phase. Another possible explanation is that the relative mRNA expression of gene ATGL was upregulated by RIF supplementation during the growing (P < 0.1) and the fattening phases (P < 0.05), while the genes associated with fatty acid uptake (FABP4) and esterification (DGAT2) were downregulated during the growing phase and upregulated (P < 0.1) during the fattening phase. This implies that the lipid turnover rate was higher for steers during the growing than fattening phase. This study demonstrated that RIF supplementation during the growing phase induced a carryover effect on the lipogenic transcriptional regulation involved in adipocyte lipid content of intramuscular adipose tissue; increased triacylglycerol hydrolysis during the growing phase subsequently was followed by increased lipid accumulation during the fattening phases.