Decreased fasting serum glucogenic amino acids with a higher compared to normal protein diet during energy restriction in women: a randomized controlled trial

Dietary protein alters circulating amino acid (AAs) levels and higher protein intake (HP) is one means of losing weight. We examined 34 overweight and obese women (57 ± 4 years) during 6 months of energy restriction (7.3 ± 3.8% weight loss) divided into groups consuming either normal protein (NP; 18.6 energy% protein) or HP (24.3 energy% protein). There was a reduction in fasting serum glucogenic AAs (p = 0.015) that also associated with greater weight loss (p < 0.05) in the HP group, but not in the NP group. These findings have implications for nutrient prioritization during energy restriction.

Impact of gestational electronic cigarette vaping on amino acid signature profile in the pregnant mother and the fetus

Background

Electronic cigarettes (e-cigs) are a form of tobacco product that has become increasingly popular over the past decade. Despite the known health consequences of tobacco product exposure during pregnancy, a substantial number of daily smokers will continue to smoke during pregnancy. Our current knowledge on the effects of e-cig aerosol exposure during pregnancy is limited to a small number of animal studies, which have identified several e-cig aerosol-induced disruptions to the physiology of normal development.

Methods

To further assess the impact of prenatal e-cig aerosol exposure on maternal and fetal health, we examined the amino acid signature profiles in maternal and fetal plasma, as well as in the fetal lungs, a sensitive target organ for prenatal tobacco product exposure. Pregnant Sprague Dawley rats were randomly assigned to one of three groups and were exposed to either e-cig aerosols containing nicotine, e-cig aerosols without nicotine, or room air. Dams were exposed utilizing a state-of-the-art custom engineered e-cig vaping system that is compatible with commercially available e-cig atomizers and enables a translational inhalation delivery method comparable to human vaping.

Results

We determined that gestational exposure to e-cig aerosols results in significant alterations to the amino acid profile in the maternal and fetal compartments, including the fetal lungs. The data shows a targeted disruption to the nitric oxide pathway, branched-chain amino acid metabolism, fetal protein synthesis, and urea cycle.

Conclusion

The data presented herein provides additional support that gestational e-cig aerosol exposure can impact crucial biological processes and exemplifies the need for extensive research on exposure to e-cig aerosols.

•

First report of e-cig induced alterations to maternal/fetal amino acid profile.

•

Translational vaping paradigm utilizing custom engineered vaping system.

•

Analysis of amino acids show gestational e-cig exposure has significant effects.

•

Fetal lungs may be a sensitive target to gestational e-cig aerosol exposure.

•

Marker of dysregulation in branched-chain amino acid metabolism and urea cycle.

Amino Acids and Their Metabolites for Improving Human Exercising Performance

Achieving adequate nutrition for exercising humans is especially important for improving both muscle mass and metabolic health. One of the most common misunderstandings in the fitness industry is that the human body has requirements for dietary whole protein and that exercising individuals must consume only whole protein to meet their physiological needs. This view, however, is incorrect. Instead, humans at rest or during exercise have requirements for dietary amino acids (AAs), and dietary protein is a source of AAs in the body. The requirements for AAs must be met each day to avoid a negative nitrogen balance in individuals with moderate or intense physical activity. By properly meeting increased requirements for AAs through increased intake of high-quality protein (the source of AAs) plus supplemental AAs, athletes can improve their overall athletic performance. AAs or metabolites that are of special importance for exercising individuals include arginine, branched-chain AAs, creatine, glycine, taurine, and glutamine. The AAs play vital roles as both substrates for protein synthesis and molecules for regulating blood flow and nutrient metabolism. The functional roles of AAs include the maintenance of cell and tissue integrity; stimulation of mechanistic target of rapamycin and AMP-activated protein kinase cell signaling pathways; energy sources for the small intestine, cells of the immune system, and skeletal muscle; antioxidant and anti-inflammatory reactions; production of neurotransmitters; modulation of acid-base balance in the body. All of those roles are crucial for the overall goal of improving exercise performance. Therefore, adequate intakes of proteinogenic AAs and their functional metabolites, especially those noted in this review, are essential for optimal human health (including optimum muscle mass and function) and should be a primary goal of exercising individuals.

Genome-wide scanning for CHD1L gene in papillary thyroid carcinoma complicated with type 2 diabetes mellitus

PURPOSE

Papillary thyroid carcinoma (PTC) represents the most common subtype of thyroid cancer (TC). This study was set out to explore the potential effect of CHD1L on PTC and type 2 diabetes mellitus (T2DM).

METHODS

We searched for T2DM susceptibility genes through the GWAS database and obtained T2DM-related differentially expressed gene from the GEO database. The expression and clinical data of TC and normal samples were collated from the TCGA database. Receiver operating characteristic (ROC) curve analysis was subsequently applied to assess the sensitivity and specificity of the CHD1L for the diagnosis of PTC. The MCP-counter package in R language was then utilized to generate immune cell score to evaluate the relationship between CHD1L expression and immune cells. Then, we performed functional enrichment analysis of co-expressed genes and DEGs to determine significantly enriched GO terms and KEGG to predict the potential functions of CHD1L in PTC samples and T2DM adipose tissue.

RESULTS

From two genes (ABCB9, CHD1L) were identified to be DEGs (p < 1 * 10^-5) that exerted effects on survival (HR > 1, p < 0.05) in PTC and served as T2DM susceptibility genes. The gene expression matrix-based scoring of immunocytes suggested that PTC samples with high and low CHD1L expression presented with significant differences in the tumor microenvironment (TME). The enrichment analysis of CHD1L co-expressed genes and DEGs suggested that CHD1L was involved in multiple pathways to regulate the development of PTC. Among them, Kaposi sarcoma-associated herpesvirus infection, salmonella infection and TNF signaling pathways were highlighted as the three most relevant pathways. GSEA analysis, employed to analyze the genome dataset of PTC samples and T2DM adipose tissue presenting with high and low expression groups of CHD1L, suggests that these differential genes are related to chemokine signaling pathway, leukocyte transendothelial migration and TCELL receptor signaling pathway.

CONCLUSION

CHD1L may potentially serve as an early diagnostic biomarker for PTC, and a target of immunotherapy for PTC and T2DM.

Dietary L-arginine supplementation during days 14-25 of gestation enhances aquaporin expression in the placentae and endometria of gestating gilts

This study tested the hypothesis that dietary L-arginine (Arg) supplementation to pregnant gilts enhanced the expression of water channel proteins [aquaporins (AQPs)] in their placentae and endometria. Gilts were fed twice daily 1 kg of a corn and soybean meal-based diet supplemented with 0.0%, 0.4%, or 0.8% Arg between Days 14 and 25 of gestation. On Days 25 and 60 of gestation, gilts were hysterectomized to obtain placentae and endometria. On Day 25 of gestation, supplementation with 0.4% Arg increased (P < 0.05) the abundance of placental AQP9 protein, whereas supplementation with 0.8% Arg increased (P < 0.05) placental AQP1 and AQP9 proteins, compared with controls. On Day 60 of gestation, supplementation with 0.4% Arg increased (P < 0.05) endometrial AQP1 protein, whereas supplementation with 0.8% Arg increased (P < 0.05) endometrial AQP5 and AQP9 proteins. Supplementation with 0.8% Arg increased the endometrial expression of AQP1, AQP5, and AQP9 proteins located in the luminal epithelium and glandular epithelium of endometria, and placental transport of ³H₂O. Collectively, these results indicate that dietary Arg supplementation stimulates the expression of selective AQPs in porcine placenta and endometria, thereby enhancing water transport from mother to fetus and expanding the chorioallantoic membranes during the period of placentation.

Placental adaptation to maternal malnutrition

Maternal malnutrition gives rise to both short- and long-term consequences for the survival and health of the offspring. As the intermediary between mother and fetus, the placenta has the potential to interpret environmental signals, such as nutrient availability, and adapt to support fetal growth and development. While this potential is present, it is clear that at times, placental adaptation fails to occur resulting in poor pregnancy outcomes. This review will focus on placental responses to maternal undernutrition related to changes in placental vascularization and hemodynamics and placental nutrient transport systems across species. While much of the available literature describes placental responses that result in poor fetal outcomes, novel models have been developed to utilize the inherent variation in fetal weight when dams are nutrient restricted to identify placental adaptations that result in normal weight offspring. Detailed analyses of the spectrum of placental responses to maternal malnutrition point to alternations in placental histoarchitectural and vascular development, amino acid and lipid transport mechanisms, and modulation of immune related factors. Dietary supplementation with select nutrients, such as arginine, have the potential to improve placental growth and function through a variety of mechanisms including stimulating cell proliferation, protein synthesis, angiogenesis, vasodilation, and gene regulation. Improved understanding of placental responses to environmental cues is necessary to develop diagnostic and intervention strategies to improve pregnancy outcomes.

Dietary Supplementation with Glycine Enhances Intestinal Mucosal Integrity and Ameliorates Inflammation in C57BL/6J Mice with High-Fat Diet-Induced Obesity

BACKGROUND

Obesity, a major public health problem worldwide, is associated with dysfunction of the intestinal barrier. Glycine (Gly) has been reported to enhance the expression of tight-junction proteins in porcine enterocytes. It is unknown whether Gly can improve intestinal barrier integrity in obese mice.

OBJECTIVES

This study tested the hypothesis that Gly enhances the intestinal epithelial barrier by regulating endoplasmic reticulum (ER) stress-related signaling and mitigating inflammation in high-fat diet (HFD)-induced obese mice.

METHODS

Five-week-old male C57BL/6J mice were fed a normal-fat diet (ND; fat = 10% energy) or an HFD (fat = 60% energy) and received drinking water supplemented with 2% Gly or 2.37% l-alanine (Ala; isonitrogenous control) daily for 12 wk. Body weight gain and tissue weights, glucose tolerance and the activation of immune cells, as well as the abundances of tight-junction proteins, ER stress proteins, and apoptosis-related proteins in the jejunum and colon were determined. In addition, the body weights of naïve ND and HFD groups (nND and nHFD, respectively) were also recorded for comparison. Differences were analyzed statistically by ANOVA followed by the Duncan multiple-comparison test using SAS software.

RESULTS

Compared with ND-Ala, HFD-feeding resulted in enhanced macrophage (CD11b+ and F4/80+) infiltration and immune cell activation by 1.9- to 5.4-fold (P < 0.05), as well as the upregulation of ER stress sensor proteins (including phospho-inositol-requiring enzyme 1α and binding immunoglobulin protein) by 2.5- to 4.5-fold, the induction of apoptotic proteins by 1.5- to 3.2-fold, and decreased abundances of tight-junction proteins by 35%-65% (P < 0.05) in the intestine. These HFD-induced abnormalities were significantly ameliorated by Gly supplementation in the HFD-Gly group (P < 0.05). Importantly, Gly supplementation also significantly enhanced glucose tolerance (P < 0.05) by 1.5-fold without affecting the fat accumulation of HFD-induced obese mice.

CONCLUSIONS

Gly supplementation enhanced the intestinal barrier and ameliorated inflammation and insulin resistance in HFD-fed mice. These effects of Gly were associated with reduced ER stress-related apoptosis in the intestine of obese mice.

MiRNA-324-5p inhibits inflammatory response of diabetic vessels by targeting CPT1A

OBJECTIVE

The purpose of this study was to elucidate the regulatory role of microRNA-324-5p (miRNA-324-5p) in inhibiting inflammatory response of diabetic vessels by regulating CPT1A level, thus alleviating the development of type 2 diabetes mellitus (T2DM).

PATIENTS AND METHODS

Arterial vessels (splenic artery) and serum exosomes were extracted from 30 T2DM patients and 30 non-T2DM subjects treated in Binzhou People's Hospital from 2015 to 2019. Relative levels of miRNA-324-5p and CPT1A in each subject were detected. Then, VSMCs were induced with high-glucose, followed by detection of inflammatory factor levels. Next, the regulatory effects of miRNA-324-5p and CPT1A on viability, 5-Ethynyl-2'-deoxyuridine (EdU)-positive ratio, and release of inflammatory factors in VSMCs were determined. Finally, Dual-Luciferase reporter assay was conducted to verify the interaction between miRNA-324-5p and CPT1A.

RESULTS

The results revealed that compared with non-T2DM subjects, miRNA-324-5p was downregulated in splenic arteries and exosomes in T2DM patients. High-glucose treatment in VSMCs triggered the release of the inflammatory factors. In addition, the overexpression of miRNA-324-5p in VSMCs reduced viability and inflammatory factor levels, and the inhibited trends were partially reversed by overexpression of CPT1A. CPT1A was indicated to be the target gene binding miRNA-324-5p.

CONCLUSIONS

MiRNA-324-5p exerts an inhibitory effect on T2DM-induced inflammation in blood vessels by negatively regulating CPT1A level and reducing the release of inflammatory factors. MiRNA-324-5p might be a promising therapeutic target for T2DM.

Genomic Effects of Arginine on Cell Behavior of Conceptus Trophectoderm in Ungulates

Hatched ungulate (e.g., pigs, sheep and other ruminants) blastocysts undergo dramatic morphological transitions from spherical to tubular to filamentous forms to conceptuses (embryo/fetus and associated extraembryonic membranes) before implantation. L-Arginine (Arg), a conditionally essential amino acid, is required for this process to activate the mTOR cell signaling pathway to induce proliferation of both porcine and ovine conceptus trophectoderm cells. However, the genomic effects of arginine on trophectoderm cells is unknown. RNA-seq was used for a comparative transcriptome analysis of porcine and ovine trophectoderm cells to further understand effects of Arg on regulation of metabolism in trophectoderm cells. An established porcine trophectoderm (pTr) cell line isolated from D12 porcine conceptuses, as well as an established ovine trophectoderm (oTr) cell line isolated from D15 ovine conceptuses were used to determine response to Arg at the physiological concentration of 0.2 mM in a 48-h culture. In pTr cells, a total of 2,723 differentially expressed genes (DEG; 1,482 up and 1,241 down) were identified in response to Arg. In oTr cells, a total of 5,369 DEG (2,819 up and 2,550 down) were detected. Comparison analyses showed that the Arg-treated pTr and oTr transcriptomes share 873 common DEG (273 up and 342 down). Canonical pathway analyses identified the top enriched pathways in both pTr and oTr cells, including activation of actin cytoskeleton signaling, adrenomedullin signaling, and IGF-1 signaling; and inhibition of cell cycle G2/M checkpoint regulation, and p53 signaling. In response to Arg, pathways associated with cholesterol biosynthesis, and estrogen-mediated S-phase entry were exclusively activated in the pTr cells; whereas interferon signaling, ephrin receptor signaling, and integrin signaling were specifically activated in the oTr cells. Results from this study advance understanding of mechanisms responsible for elongation of ovine and porcine conceptuses and enable the rational design of future experiments.

Pre-implantation exogenous progesterone and pregnancy in sheep. II. Effects on fetal-placental development and nutrient transporters in late pregnancy

BACKGROUND

Administration of progesterone (P4) to ewes during the first 9 to 12 days of pregnancy accelerates blastocyst development by day 12 of pregnancy, likely due to P4-induced up-regulation of key genes in uterine epithelia responsible for secretion and transport of components of histotroph into the uterine lumen. This study determined if acceleration of blastocyst development induced by exogenous P4 during the pre-implantation period affects fetal-placental development on day 125 of pregnancy. Suffolk ewes (n = 35) were mated to fertile rams and assigned randomly to receive daily intramuscular injections of either corn oil vehicle (CO, n = 18) or 25 mg progesterone in CO (P4, n = 17) for the first 8 days of pregnancy. All ewes were hysterectomized on day 125 of pregnancy and: 1) fetal and placental weights and measurements were recorded; 2) endometrial and placental tissues were analyzed for the expression of candidate mRNAs involved in nutrient transport and arginine metabolism; and 3) maternal plasma, fetal plasma, allantoic fluid, and amniotic fluid were analyzed for amino acids, agmatine, polyamines, glucose, and fructose.

RESULTS

Treatment of ewes with exogenous P4 did not alter fetal or placental growth, but increased amounts of aspartate and arginine in allantoic fluid and amniotic fluid, respectively. Ewes that received exogenous P4 had greater expression of mRNAs for SLC7A1, SLC7A2, SLC2A1, AGMAT, and ODC1 in endometria, as well as SLC1A4, SLC2A5, SLC2A8 and ODC1 in placentomes. In addition, AZIN2 protein was immunolocalized to uterine luminal and glandular epithelia in P4-treated ewes, whereas AZIN2 localized only to uterine luminal epithelia in CO-treated ewes.

CONCLUSIONS

This study revealed that exogenous P4 administered in early pregnancy influenced expression of selected genes for nutrient transporters and the expression of a protein involved in polyamine synthesis on day 125 of pregnancy, suggesting a 'programming' effect of P4 on gene expression that affected the composition of nutrients in fetal-placental fluids.

Cell-Specific Expression of Enzymes for Serine Biosynthesis and Glutaminolysis in Farm Animals

During the peri-implantation period, conceptuses [embryo and placental membranes, particularly the trophectoderm (Tr)] of farm animals (e.g., sheep and pigs) rapidly elongate from spherical to tubular to filamentous forms. In concert with Tr outgrowth during conceptus elongation, the Tr of sheep and pig conceptuses attaches to the endometrial luminal epithelium (LE) to initiate placentation. In sheep, binucleate cells (BNCs) begin to differentiate from the mononuclear trophectoderm cells and migrate to the endometrial LE to form syncytial plaques. These events require Tr cells to expend significant amounts of energy to undergo timely and extensive proliferation, migration and fusion. It is likely essential that conceptuses optimally utilize multiple biosynthetic pathways to convert molecules such as glucose, fructose, and glutamine (components of histotroph transport by sheep and pig endometria into the uterine lumen), into ATP, amino acids, ribose, hexosamines and nucleotides required to support early conceptus development and survival. Elongating and proliferating conceptus Tr cells potentially act, in a manner similar to cancer cells, to direct carbon generated from glucose and fructose away from the TCA cycle for utilization in branching pathways of glycolysis, including the pentose phosphate pathway, one-carbon metabolism, and hexosamine biosynthesis. The result is a limited availability of pyruvate for maintaining the TCA cycle within mitochondria, and Tr cells replenish TCA cycle metabolites via a process known as anaplerosis, primarily through glutaminolysis to convert glutamine into TCA cycle intermediates. Here we describe the cell-specific expression of enzymes required for serine biosynthesis, one-carbon metabolism and glutaminolysis at the uterine-placental interface of sheep and pigs, and propose that these biosynthetic pathways are essential to support early placental development including Tr elongation, cell migration, cell fusion and implantation by ovine and porcine conceptuses.

Nutrition and Functions of Amino Acids in Fish

Aquaculture is increasingly important for providing humans with high-quality animal protein to improve growth, development and health. Farm-raised fish and shellfish now exceed captured fisheries for foods. More than 70% of the production cost is dependent on the supply of compound feeds. A public debate or concern over aquaculture is its environmental sustainability as many fish species have high requirements for dietary protein and fishmeal. Protein or amino acids (AAs), which are the major component of tissue growth, are generally the most expensive nutrients in animal production and, therefore, are crucial for aquatic feed development. There is compelling evidence that an adequate supply of both traditionally classified nutritionally essential amino acids (EAAs) and non-essential amino acids (NEAAs) in diets improve the growth, development and production performance of aquatic animals (e.g., larval metamorphosis). The processes for the utilization of dietary AAs or protein utilization by animals include digestion, absorption and metabolism. The digestibility and bioavailability of AAs should be carefully evaluated because feed production processes and AA degradation in the gut affect the amounts of dietary AAs that enter the blood circulation. Absorbed AAs are utilized for the syntheses of protein, peptides, AAs, and other metabolites (including nucleotides); biological oxidation and ATP production; gluconeogenesis and lipogenesis; and the regulation of acid-base balance, anti-oxidative reactions, and immune responses. Fish producers usually focus on the content or digestibility of dietary crude protein without considering the supply of AAs in the diet. In experiments involving dietary supplementation with AAs, inappropriate AAs (e.g., glycine and glutamate) are often used as the isonitrogenous control. At present, limited knowledge is available about either the cell- and tissue-specific metabolism of AAs or the effects of feed processing methods on the digestion and utilization of AAs in different fish species. These issues should be addressed to develop environment-friendly aquafeeds and reduce feed costs to sustain the global aquaculture.

Amino Acids in the Nutrition, Metabolism, and Health of Domestic Cats

Domestic cats (carnivores) require high amounts of dietary amino acids (AAs) for normal growth, development, and reproduction. Amino acids had been traditionally categorised as nutritionally essential (EAAs) or nonessential (NEAAs), depending on whether they are synthesized de novo in the body. This review will focus on AA nutrition and metabolism in cats. Like other mammals, cats do not synthesize the carbon skeletons of twelve proteinogenic AAs: Arg, Cys, His, Ile, Leu, Lys, Met, Phe, Thr, Trp, Tyr, and Val. Like other feline carnivores but unlike many mammals, cats do not synthesize citrulline and have a very limited ability to produce taurine from Cys. Except for Leu and Lys that are strictly ketogenic AAs, most EAAs are both glucogenic and ketogenic AAs. All the EAAs (including taurine) must be provided in diets for cats. These animals are sensitive to dietary deficiencies of Arg and taurine, which rapidly result in life-threatening hyperammonemia and retinal damage, respectively. Although the National Research Council (NCR, Nutrient requirements of dogs and cats. National Academies Press, Washington, DC, 2006) does not recommend dietary requirements of cats for NEAAs, much attention should be directed to this critical issue of nutrition. Cats can synthesize de novo eight proteinogenic AAs: Ala, Asn, Asp, Gln, Glu, Gly, Pro, and Ser, as well as some nonproteinogenic AAs, such as γ-aminobutyrate, ornithine, and β-alanine with important physiological functions. Some of these AAs (e.g., Gln, Glu, Pro, and Gly) are crucial for intestinal integrity and health. Except for Gln, AAs in the arterial blood of cats may not be available to the mucosa of the small intestine. Plant-source foodstuffs lack taurine and generally contain inadequate Met and Cys and, therefore, should not be fed to cats in any age group. Besides meat, animal-source foodstuffs (including ruminant meat & bone meal, poultry by-product meal, porcine mucosal protein, and chicken visceral digest) are good sources of proteinogenic AAs and taurine for cats. Meeting dietary requirements for both EAAs and NEAAs in proper amounts and balances is crucial for improving the health, wellbeing, longevity, and reproduction of cats.

Multiclass CBCT Image Segmentation for Orthodontics with Deep Learning

Accurate segmentation of the jaw (i.e., mandible and maxilla) and the teeth in cone beam computed tomography (CBCT) scans is essential for orthodontic diagnosis and treatment planning. Although various (semi)automated methods have been proposed to segment the jaw or the teeth, there is still a lack of fully automated segmentation methods that can simultaneously segment both anatomic structures in CBCT scans (i.e., multiclass segmentation). In this study, we aimed to train and validate a mixed-scale dense (MS-D) convolutional neural network for multiclass segmentation of the jaw, the teeth, and the background in CBCT scans. Thirty CBCT scans were obtained from patients who had undergone orthodontic treatment. Gold standard segmentation labels were manually created by 4 dentists. As a benchmark, we also evaluated MS-D networks that segmented the jaw or the teeth (i.e., binary segmentation). All segmented CBCT scans were converted to virtual 3-dimensional (3D) models. The segmentation performance of all trained MS-D networks was assessed by the Dice similarity coefficient and surface deviation. The CBCT scans segmented by the MS-D network demonstrated a large overlap with the gold standard segmentations (Dice similarity coefficient: 0.934 ± 0.019, jaw; 0.945 ± 0.021, teeth). The MS-D network–based 3D models of the jaw and the teeth showed minor surface deviations when compared with the corresponding gold standard 3D models (0.390 ± 0.093 mm, jaw; 0.204 ± 0.061 mm, teeth). The MS-D network took approximately 25 s to segment 1 CBCT scan, whereas manual segmentation took about 5 h. This study showed that multiclass segmentation of jaw and teeth was accurate and its performance was comparable to binary segmentation. The MS-D network trained for multiclass segmentation would therefore make patient-specific orthodontic treatment more feasible by strongly reducing the time required to segment multiple anatomic structures in CBCT scans.

Amino Acids in Swine Nutrition and Production

Amino acids are the building blocks of proteins in animals, including swine. With the development of new analytical methods and biochemical research, there is a growing interest in fundamental and applied studies to reexamine the roles and usage of amino acids (AAs) in swine production. In animal nutrition, AAs have been traditionally classified as nutritionally essential (EAAs) or nutritionally nonessential (NEAAs). AAs that are not synthesized de novo must be provided in diets. However, NEAAs synthesized by cells of animals are more abundant than EAAs in the body, but are not synthesized de novo in sufficient amounts for the maximal productivity or optimal health (including resistance to infectious diseases) of swine. This underscores the conceptual limitations of NEAAs in swine protein nutrition. Notably, the National Research Council (NRC 2012) has recognized both arginine and glutamine as conditionally essential AAs for pigs to improve their growth, development, reproduction, and lactation. Results of recent work have also provided compelling evidence for the nutritional essentiality of glutamate, glycine, and proline for young pigs. The inclusion of so-called NEAAs in diets can help balance AAs in diets, reduce the dietary levels of EAAs, and protect the small intestine from oxidative stress, while enhancing the growth performance, feed efficiency, and health of pigs. Thus, both EAAs and NEAAs are needed in diets to meet the requirements of pigs. This notion represents a new paradigm shift in our understanding of swine protein nutrition and is transforming pork production worldwide.

Y-shaped airway self-expanding covered metallic stent removal via the interventional technique

AIM

To review the removal of Y-shaped airway self-expanding covered metallic stents using the interventional technique under fluoroscopy.

MATERIALS AND METHODS

The clinical data of 33 patients who underwent removal of Y-shaped airway self-expanding covered metallic stents from March 2011 to August 2019 were analysed retrospectively.

RESULTS

A total of 35 Y-shaped stents were removed. The average indwelling duration of the tracheal stents was 101.7 ± 105.4 days. Four cases were removed via the conventional method (grasping the upper tip of the stent to collapse and adduct the proximal end of the stent), whereas 31 cases were removed using the reversal method (grasping the distal end of the stent to invert and strip out the stent). The duration of stent removal was 24.3 ± 12.4 minutes (median time, 20 minutes).

CONCLUSION

The interventional radiology technique is a feasible, safe, and effective method for removing Y-shaped airway self-expanding covered metallic stents, and can be considered for use in the clinical setting.

Pre-implantation exogenous progesterone and pregnancy in sheep: I. polyamines, nutrient transport, and progestamedins

Background

Administration of exogenous progesterone (P4) to ewes during the pre-implantation period advances conceptus development and implantation. This study determined effects of exogenous P4 on transport of select nutrients and pathways that enhance conceptus development. Pregnant ewes (n = 38) were treated with either 25 mg P4 in 1 mL corn oil (P4, n = 18) or 1 mL corn oil alone (CO, n = 20) from day 1.5 through day 8 of pregnancy and hysterectomized on either day 9 or day 12 of pregnancy. Endometrial expression of genes encoding enzymes for synthesis of polyamines, transporters of glucose, arginine, and glycine, as well as progestamedins was determined by RT-qPCR.

Results

On day 12 of pregnancy, conceptuses from P4-treated ewes had elongated while those from CO-treated ewes were spherical. The mRNA expression of AZIN2, an arginine decarboxylase, was lower in endometria of P4-treated than CO-treated ewes on day 9 of pregnancy. Expression of FGF10, a progestamedin, was greater in endometria of CO and P4-treated ewes on day 12 of gestation in addition to P4-treated ewes necropsied on day 9 of gestation. Treatment with P4 down-regulated endometrial expression of amino acid transporter SLC1A4 on day 12 of pregnancy.

Conclusions

Results indicated that administration of exogenous P4 during the pre-implantation period advanced the expression of FGF10, which may accelerate proliferation of trophectoderm cells, but also was correlated with decreased expression of glycine and serine transporters and polyamine synthesis enzyme AZIN2. Further research with increased sample sizes may determine how differential expression affects endometrial functions and potentially embryonic loss.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-021-00554-6.

A3 THE LOSS OF THE CIRCADIAN CLOCK GENE BMAL1 INCREASES TUMOUR INITIATION IN APCMIN MICE

Background

Circadian rhythms are autonomously running 24h cycles in bodily processes. In animals these rhythms are driven by a molecular time keeper known as the circadian clock. The clock is a transcription-translation feedback loop composed of the transcription factors Bmal1 and Clock as well as their repressors Per and Cry. The circadian clock regulates over 40% of the genome rhythmically. Chronic circadian disruption, in the case of shift work, can lead to pathologies including cancer. Colorectal cancer is most frequently initiated through a mutation in the Wnt pathway regulator, Apc. Several studies have attempted to provide a mechanistic link between cancer and circadian clock disruption but the use of mice on mixed genetic backgrounds and poor circadian models have made this link unclear.

Aims

We aim to determine if the circadian clock plays a role in intestinal tumourigenesis.

Methods

We crossed the Apcmin mouse strain, a common intestinal tumour model, with Bmal1 mutant mice, which lack a functioning circadian clock. After creating an isogenic strain, we examined the number of tumours in control (Bmal1+/+) and clock dead (Bmal1-/-) animals. We derived organoids, a 3D cell culture method, from Apc+/+; Bmal1+/+ (healthy, clock-live), Apc+/+, Bmal1-/-(healthy, clock-dead), Apcmin; Bmal1+/+(adenoma, clock-live), Apcmin; Bmal1-/- (adenoma, clock-live) mouse ileum and collected every 2h from 24-48h after synchronizing their circadian clock. Collected samples were sent for RNA sequencing and assessed for circadian regulated transcripts. This experiment was followed up by in vitro organoid assays.

Results

The circadian clock controls 41 genes in the intestinal epithelium, including genes like Tead4 which are known to be important in intestinal biology. There are twofold more tumours in Bmal1-/- mice than their Bmal1+/+ littermates, and Bmal1-/- tumours upregulate Tead4 and Hippo pathway targets and downregulate Wnt pathway targets. Bmal1-/- adenoma organoids show increased self-renewal when compared to Bmal1+/+ adenoma organoids. However, this increase in self-renewal is lost when organoids are treated with inhibitors of the hippo pathway.

Conclusions

The circadian clock is important in maintaining the health of an organism, and disruption of the clock can lead to many health consequences including cancer. We show for the first time that the circadian clock controls the hippo signaling mediator Tead4. Additionally, we show that the loss of the clock leads to an increase in the number of tumours present in the epithelium which are characterized by an increase in hippo signaling. This research shows the important of considering time of day when studying stem cells during homeostasis and in cancer.

Funding Agencies

CIHRNSERC

Paraoxonase 2 protects against oxygen-glucose deprivation/reoxygenation-induced neuronal injury by enhancing Nrf2 activation via GSK-3β modulation

Paraoxonase 2 (PON2) is a powerful antioxidant that mediates cell survival under oxidative stress; however, its protection neurons against cerebral ischemia-reperfusion injury-induced oxidative stress remains unclear. This study aimed to determine the precise regulating role of PON2 in neuronal survival under oxidative stress. An in vitro model of cerebral ischemia-reperfusion injury was used to assess the effect of PON2 on oxidative stress induced by oxygen-glucose deprivation/reoxygenation (OGD/R). Results showed that PON2 expression in neurons was decreased due to OGD/R exposure. A series of functional experiments revealed that upregulated PON2 improved OGD/R-impaired viability and attenuated OGD/R-induced increases in apoptosis and reactive oxygen species in neurons. Decreased PON2 expression enhanced neuronal sensitivity to OGD/R-induced injury. Overexpressed PON2 markedly enhanced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) in the nucleus and increased the levels of Nrf2-mediated transcriptional activity. Furthermore, PON2 enhanced the Nrf2 activation by modulating glycogen synthase kinase-3β (GSK-3β). Inhibition of GSK-3β substantially abrogated the PON2 knockdown-mediated suppression of Nrf2 activity. Notably, Nrf2 inhibition partially reversed the neuroprotective effects of PON2 overexpression in OGD/R-exposed neurons. These findings indicate that PON2 alleviates OGD/R-induced apoptosis and oxidative stress in neurons by potentiating Nrf2 activation via GSK-3β modulation. This study highlights the potential neuroprotective function of PON2 against cerebral ischemia-reperfusion injury.

Intrauterine growth restriction alters nutrient metabolism in the intestine of porcine offspring

Background

Intrauterine growth restriction (IUGR) has negative impacts on the postnatal survival, growth and development of humans and animals, with not only on newborns but also adulthood. However, the characteristics for nutrient digestion and absorption in IUGR offspring are still largely unknown. Therefore, the normal birth weight (NBW) and IUGR growing pigs were used in this study to investigate their differences in nutrient utilization, with an expectition for further nutritional optimization of the IUGR offspring during their later life.

Methods

Twelve IUGR and 12 NBW growing pigs were fitted with catheters in their portal vein to measure blood flow rate as well as nutrients and metabolites in plasma. The digestibilities of nutrients in different intestinal segments, and bacterial fermentation in the large intestine were examined to reveal the characteristics of nutrients utilization in IUGR versus NBW pigs.

Results

The rate of portal venous blood flow did not differ beween IUGR and NBW pigs. Plasma concentrations of total cholesterol, triglycerides and glucose were much lower but those of urea were higher in the portal vein of IUGR pigs, compared with the NBW pigs. The ileal digestibility of dry matter, gross energy and starch were lower in IUGR pigs than in NBW pigs. IUGR increased hindgut microbial diversity and bacterial fermentation activity in the caecum. In vitro cross-fermentation of ileal digesta by caecal microbes of NBW and IUGR pigs showed that gas production was much higher for IUGR ileal digesta regardless of the source of caecal inocula.

Conclusion

IUGR impairs the nutrient digestion and absorption in small intestine, reduces caecal microbial diversity and promotes bacterial fermentation in the large intestine during the growing phase. These findings aid in our understanding of nutrient metabolism in IUGR pigs and provide the basis for future nutritional interventions.

[Application of 3D-CT simulation image in the description of gastric artery variation to guide laparoscopic total gastrectomy]

Objective: Anatomic variations in the perigastric vessels during laparoscopic radical gastrectomy often affect the operator's judgment and prolong the operation time, and even cause accidental injury and surgical complications, and hence the safety and quality of the operation cannot be ensured. In this study, multiple slice CT was reconstructed by 3-dimensional CT simulation software (3D-CT), and 3D-CT images were used to describe the variation of celiac trunk and splenic artery before surgery. The guiding role of the different variation of vessels was analyzed for laparoscopic total gastrectomy+D2 lymph node dissection (LTG+D2LD). Methods: A retrospective cohort study was conducted. Case inclusion criteria: (1) Gastric cancer was at an advanced stage. All the patients were preoperatively examined by digestive endoscopy and 64-row enhanced CT scan, and were histopathologically diagnosed with gastric adenocarcinoma. (2) 3D-CT simulation images were reconstructed to guide the operation. (3) LTG+D2LD surgery was performed by the same surgical team. (4) Clinical data were complete, and all the patients had signed the informed consent. From 2014 to 2018, 98 patients with gastric cancer at the Gastrointestinal Surgery Department of Henan Provincial People's Hospital were enrolled. According to the Adachi classification, celiac trunk variation was divided into common type (Adachi type I) and rare type (Adachi type II-VI). According to the Natsume classification, splenic artery was classified into "flat type" and "curved type". Based on 3D-CT simulation images, variation of celiac trunk and splenic artery was described, and the differences in operation time, intraoperative blood loss and the number of postoperative retrieved lymph nodes were compared between groups with different types of arterial variation. Results: For celiac trunk, common type was found in 84 cases (86%) and rare type was found in 14 cases, including 6 cases (6%) of type II, 2 cases (2%) of type III, 2 cases (2%) of type IV, 3 cases (3%) of type V, 1 case (1%) of type VI. No other types were found. There were no statistically significant differences in clinical characteristics and number of retrieved lymph nodes between patients of the common type group and rare type group (all P>0.05). Compared with common type patients, those of rare type had longer operative time [(321.1±29.0) minutes vs. (295.1±46.5) minutes, t=2.081, P=0.040] and more intraoperative blood loss (median: 66.0 ml vs. 32.0 ml, Z=-4.974, P=0.001). For splenic artery, 41 patients (42%) were flat type and 57 patients (58%) were curved type. There were no statistically significant differences between the two groups in terms of clinical characteristics, intraoperative blood loss, operative time and number of retrieved lymph nodes (all P>0.05). Conclusions: The method of describing the variation in the perigastric vessels by 3D-CT simulation has certain clinical value in laparoscopic radical gastrectomy. The duration of LTG+D2LD is prolonged and the intraoperative blood loss is increased with the variation of celiac trunk, while the variation of splenic artery has no effect on LTG+D2LD.