Maternal Diet High in Linoleic Acid Alters Renal Branching Morphogenesis and mTOR/AKT Signalling Genes in Rat Fetal Kidneys.

Linoleic acid (LA), an n-6 polyunsaturated fatty acid (PUFA), is obtained from the maternal diet during pregnancy, and is essential for normal fetal growth and development. A maternal high-LA (HLA) diet alters maternal and offspring fatty acids, maternal leptin and male/female ratio at embryonic (E) day 20 (E20). We investigated the effects of an HLA diet on embryonic offspring renal branching morphogenesis, leptin signalling, megalin signalling and angiogenesis gene expression. Female Wistar Kyoto rats were fed low-LA (LLA; 1.44% energy from LA) or high-LA (HLA; 6.21% energy from LA) diets during pregnancy and gestation/lactation. Offspring were sacrificed and mRNA from kidneys was analysed by real-time PCR. Maternal HLA decreased the targets involved in branching morphogenesis Ret and Gdnf in offspring, independent of sex. Furthermore, downstream targets of megalin, namely mTOR, Akt3 and Prkab2, were reduced in offspring from mothers consuming an HLA diet, independent of sex. There was a trend of an increase in the branching morphogenesis target Gfra1 in females (p = 0.0517). These findings suggest that an HLA diet during pregnancy may lead to altered renal function in offspring. Future research should investigate the effects an HLA diet has on offspring kidney function in adolescence and adulthood.

Maternal Diet High in Linoleic Acid Alters Offspring Lipids and Hepatic Regulators of Lipid Metabolism in an Adolescent Rat Model.

Linoleic acid (LA), an n-6 polyunsaturated fatty acid (PUFA), is essential for fetal growth and development. A maternal high LA (HLA) diet alters cardiovascular development in adolescent rats and hepatic function in adult rats in a sex-specific manner. We investigated the effects of an HLA diet on adolescent offspring hepatic lipids and hepatic lipid metabolism gene expression, and the ability of the postnatal diet to alter these effects. Female Wistar Kyoto rats were fed low LA (LLA; 1.44% energy from LA) or high LA (HLA; 6.21% energy from LA) diets during pregnancy and gestation/lactation. Offspring, weaned at postnatal day (PN) 25, were fed LLA or HLA and euthanised at PN40 (n = 6-8). Maternal HLA increased circulating uric acid, decreased hepatic cholesterol and increased hepatic Pparg in males, whereas only hepatic Srebf1 and Hmgcr increased in females. Postnatal (post-weaning) HLA decreased liver weight (% body weight) and increased hepatic Hmgcr in males, and decreased hepatic triglycerides in females. Maternal and postnatal HLA had an interaction effect on Lpl, Cpt1a and Pparg in females. These findings suggest that an HLA diet both during and after pregnancy should be avoided to improve offspring disease risk.

Changes in Essential Fatty Acids and Ileal Genes Associated with Metabolizing Enzymes and Fatty Acid Transporters in Rodent Models of Cystic Fibrosis.

Cystic fibrosis (CF), the result of mutations in the CF transmembrane conductance regulator (CFTR), causes essential fatty acid deficiency. The aim of this study was to characterize fatty acid handling in two rodent models of CF; one strain which harbors the loss of phenylalanine at position 508 (Phe508del) in CFTR and the other lacks functional CFTR (510X). Fatty acid concentrations were determined using gas chromatography in serum from Phe508del and 510X rats. The relative expression of genes responsible for fatty acid transport and metabolism were quantified using real-time PCR. Ileal tissue morphology was assessed histologically. There was an age-dependent decrease in eicosapentaenoic acid and the linoleic acid:α-linolenic acid ratio, a genotype-dependent decrease in docosapentaenoic acid (n-3) and an increase in the arachidonic acid:docosahexaenoic acid ratio in Phe508del rat serum, which was not observed in 510X rats. In the ileum, Cftr mRNA was increased in Phe508del rats but decreased in 510X rats. Further, Elvol2, Slc27a1, Slc27a2 and Got2 mRNA were increased in Phe508del rats only. As assessed by Sirius Red staining, collagen was increased in Phe508del and 510X ileum. Thus, CF rat models exhibit alterations in the concentration of circulating fatty acids, which may be due to altered transport and metabolism, in addition to fibrosis and microscopic structural changes in the ileum.

Treatment of Diet-Induced Obese Rats with CB2 Agonist AM1241 or CB2 Antagonist AM630 Reduces Leptin and Alters Thermogenic mRNA in Adipose Tissue.

Diet-induced obesity (DIO) is a contributor to co-morbidities, resulting in alterations in hormones, lipids, and low-grade inflammation, with the cannabinoid type 2 receptor (CB2) contributing to the inflammatory response. The effects of modulating CB2 with pharmacological treatments on inflammation and adaptations to the obese state are not known. Therefore, we aimed to investigate the molecular mechanisms in adipose tissue of CB2 agonism and CB2 antagonism treatment in a DIO model. Male Sprague Dawley rats were placed on a high-fat diet (HFD) (21% fat) for 9 weeks, then received daily intraperitoneal injections with a vehicle, AM630 (0.3 mg/kg), or AM1241 (3 mg/kg), for a further 6 weeks. AM630 or AM1241 treatment in DIO rats did not alter their body weight, food intake, or liver weight, and it had no effect on their numerous circulating cytokines or peri-renal fat pad mass. AM1241 decreased heart weight and BAT weight; both treatments (AM630 or AM1241) decreased plasma leptin levels, while AM630 also decreased plasma ghrelin and GLP-1 levels. Both treatments decreased Adrb3 and TNF-α mRNA levels in eWAT and TNF-α levels in pWAT. AM630 treatment also decreased the mRNA levels of Cnr2, leptin, and Slc2a4 in eWAT. In BAT, both treatments decreased leptin, UCP1, and Slc2a4 mRNA levels, with AM1241 also decreasing Adrb3, IL1ß, and PRDM16 mRNA levels, and AM630 increasing IL6 mRNA levels. In DIO, CB2 agonist and CB2 antagonist treatment reduces circulating leptin in the absence of weight loss and modulates the mRNA responsible for thermogenesis.

Transforming growth factor ß1 impairs the transcriptomic response to contraction in myotubes from women with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is characterised by a hormonal imbalance affecting the reproductive and metabolic health of reproductive-aged women. Exercise is recommended as a first-line therapy for women with PCOS to improve their overall health; however, women with PCOS are resistant to the metabolic benefits of exercise training. Here, we aimed to gain insight into the mechanisms responsible for such resistance to exercise in PCOS. We employed an in vitro approach with electrical pulse stimulation (EPS) of cultured skeletal muscle cells to explore whether myotubes from women with PCOS have an altered gene expression signature in response to contraction. Following EPS, 4719 genes were differentially expressed (false discovery rate <0.05) in myotubes from women with PCOS compared to 173 in healthy women. Both groups included genes involved in skeletal muscle contraction. We also determined the effect of two transforming growth factor ß (TGFß) ligands that are elevated in plasma of women with PCOS, TGFß1 and anti-Müllerian hormone (AMH), alone and on the EPS-induced response. While AMH (30 ng/ml) had no effect, TGFß1 (5 ng/ml) induced the expression of extracellular matrix genes and impaired the exercise-like transcriptional signature in myotubes from women with and without PCOS in response to EPS by interfering with key processes related to muscle contraction, calcium transport and actin filament. Our findings suggest that while the fundamental gene expression responses of skeletal muscle to contraction is intact in PCOS, circulating factors like TGFß1 may be responsible for the impaired adaptation to exercise in women with PCOS. KEY POINTS: Gene expression responses to in vitro contraction (electrical pulse stimulation, EPS) are altered in myotubes from women with polycystic ovary syndrome (PCOS) compared to healthy controls, with an increased expression of genes related to pro-inflammatory pathways. Transforming growth factor ß1 (TGFß1) upregulates genes related to extracellular matrix remodelling and reduces the expression of contractile genes in myotubes, regardless of the donor's health status. TGFß1 alters the gene expression response to EPS, providing a possible mechanism for the impaired exercise adaptations in women with PCOS.

High-intensity training elicits greater improvements in cardio-metabolic and reproductive outcomes than moderate-intensity training in women with polycystic ovary syndrome: a randomized clinical trial.

STUDY QUESTION: Does 12 weeks of high-intensity interval training (HIIT) result in greater improvements in cardio-metabolic and reproductive outcomes compared to standard moderate-intensity continuous training (MICT) in women with polycystic ovary syndrome (PCOS)? SUMMARY ANSWER: HIIT offers greater improvements in aerobic capacity, insulin sensitivity and menstrual cyclicity, and larger reductions in hyperandrogenism compared to MICT. WHAT IS KNOWN ALREADY: Exercise training is recognized to improve clinical outcomes in women with PCOS, but little is known about whether HIIT results in greater health outcomes compared to standard MICT. STUDY DESIGN, SIZE, DURATION: This was a two-armed randomized clinical trial enrolling a total of 29 overweight women with PCOS between May 2016 and November 2019. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women with PCOS aged 18-45 years were randomly assigned to 12 weeks of either MICT (60-75% peak heart rate, N = 14) or HIIT (>90% peak heart rate, N = 15), each completed three times per week. The primary clinical outcomes were aerobic capacity (VO2peak) and insulin sensitivity (euglycaemic-hyperinsulinaemic clamp). Secondary outcomes included hormonal profiles, menstrual cyclicity and body composition. MAIN RESULTS AND THE ROLE OF CHANCE: Both HIIT and MICT improved VO2peak (HIIT; Δ 5.8 ± 2.6 ml/kg/min, P < 0.001 and MICT; Δ 3.2 ± 2 ml/kg/min, P < 0.001), however, the HIIT group had a greater improvement in aerobic capacity compared to MICT (ß = 2.73 ml/kg/min, P = 0.015). HIIT increased the insulin sensitivity index compared to baseline (Δ 2.3 ± 4.4 AU, P = 0.007) and MICT (ß = 0.36 AU, P = 0.030), and caused higher increases in sex hormone-binding globulin compared to MICT (ß = 0.25 nmol/l, P = 0.002). HIIT participants were 7.8 times more likely to report improved menstrual cyclicity than those in the MICT group (odds ratio 7.8, P = 0.04). LIMITATIONS, REASONS FOR CAUTION: This study has a small sample size and the findings of the effect of the exercise interventions are limited to overweight reproductive-aged women, who do not have any co-existing co-morbidities that require medication. WIDER IMPLICATIONS OF THE FINDINGS: Exercise, regardless of intensity, has clear health benefits for women with PCOS. HIIT appears to be a more beneficial strategy and should be considered for promoting health and reducing cardio-metabolic risk in overweight women with PCOS. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by a Project Support Grant from the Australian National Health and Medical Research Council (NHMRC) Centre for Research Excellence in PCOS. The authors have no conflicts of interest to disclose. TRIAL REGISTRATION NUMBER: ACTRN12615000242527. TRIAL REGISTRATION DATE: 19 February 2015. DATE OF FIRST PATIENT'S ENROLMENT: 27 May 2016.

Maternal diet high in linoleic acid alters offspring fatty acids and cardiovascular function in a rat model.

Linoleic acid (LA), an essential n-6 fatty acid (FA), is critical for fetal development. We investigated the effects of maternal high LA (HLA) diet on offspring cardiac development and its relationship to circulating FA and cardiovascular function in adolescent offspring, and the ability of the postnatal diet to reverse any adverse effects. Female Wistar Kyoto rats were fed low LA (LLA; 1·44 % energy from LA) or high LA (HLA; 6·21 % energy from LA) diets for 10 weeks before pregnancy and during gestation/lactation. Offspring, weaned at postnatal day 25, were fed LLA or HLA diets and euthanised at postnatal day 40 (n 6-8). Maternal HLA diet decreased circulating total cholesterol and HDL-cholesterol in females and decreased total plasma n-3 FA in males, while maternal and postnatal HLA diets decreased total plasma n-3 FA in females. α-Linolenic acid (ALA) and EPA were decreased by postnatal but not maternal HLA diets in both sexes. Maternal and postnatal HLA diets increased total plasma n-6 and LA, and a maternal HLA diet increased circulating leptin, in both male and female offspring. Maternal HLA decreased slopes of systolic and diastolic pressure-volume relationship (PVR), and increased cardiac Col1a1, Col3a1, Atp2a1 and Notch1 in males. Maternal and postnatal HLA diets left-shifted the diastolic PVR in female offspring. Coronary reactivity was altered in females, with differential effects on flow repayment after occlusion. Thus, maternal HLA diets impact lipids, FA and cardiac function in offspring, with postnatal diet modifying FA and cardiac function in the female offspring.

Role for animal models in understanding essential fatty acid deficiency in cystic fibrosis.

Essential fatty acid deficiency has been observed in most patients with Cystic Fibrosis (CF); however, pancreatic supplementation does not restore the deficiency, suggesting a different pathology independent of the pancreas. At this time, the underlying pathological mechanisms are largely unknown. Essential fatty acids are obtained from the diet and processed by organs including the liver and intestine, two organs significantly impacted by mutations in the cystic fibrosis transmembrane conductance regulator gene (Cftr). There are several CF animal models in a variety of species that have been developed to investigate molecular mechanisms associated with the CF phenotype. Specifically, global and systemic mutations in Cftr which mimic genotypic changes identified in CF patients have been generated in mice, rats, sheep, pigs and ferrets. These mutations produce CFTR proteins with a gating defect, trafficking defect, or an absent or inactive CFTR channel. Essential fatty acids are critical to CFTR function, with a bidirectional relationship between CFTR and essential fatty acids proposed. Currently, there are limited analyses on the essential fatty acid status in most of these animal models. Of interest, in the mouse model, essential fatty acid status is dependent on the genotype and resultant phenotype of the mouse. Future investigations should identify an optimal animal model that has most of the phenotypic changes associated with CF including the essential fatty acid deficiencies, which can be used in the development of therapeutics.

Eight weeks of combined exercise training do not alter circulating microRNAs-29a, -133a, -133b, and -155 in young, healthy men.

PURPOSE: Individuals with a family history of type 2 diabetes (FH +) have an increased risk of developing type 2 diabetes. Circulating microRNAs (miRNAs) have been implicated as biomarkers of type 2 diabetes risk. Here, we investigated if four circulating miRNAs related to glucose metabolism were altered in men with a FH + and we conducted a preliminary analysis to determine if miRNA expressions were responsive to 8 weeks of combined exercise training. METHODS: Sixteen young healthy men (mean ± SD; age 22.5 ± 2.5; BMI 26.4 ± 4.0) with FH + or without a family history of type 2 diabetes (FH -) underweight 8 weeks of combined endurance and resistance exercise training (n = 8 FH -; n = 8 FH +). The expression of miR-29a, miR-133a, miR-133b, and miR-155 were measured in serum before and after exercise training. QIAGEN's Ingenuity® Pathway Analysis was used to examine miRNA target genes and their involvement in glucose metabolism signaling pathways. RESULTS: There were no differences in miRNA expressions between FH - and FH + . Exercise training did not alter miRNA expressions in either FH - or FH + despite improvements in insulin sensitivity, aerobic capacity, and muscular strength. miR-29a and miR-155 were inversely related to fasting glucose, and miR-133a and miR-133b were negatively correlated with glucose tolerance; however, correlations were not observed with insulin sensitivity. CONCLUSIONS: The circulating miRNAs- miR-29a, miR-133a, miR-133b, and miR-155 are related to measures of glucose metabolism in healthy, normoglycemic men, but do not reflect peripheral insulin sensitivity or improvements in metabolic health following 8 weeks of combined exercise training.

CB1 Ligand AM251 Induces Weight Loss and Fat Reduction in Addition to Increased Systemic Inflammation in Diet-Induced Obesity.

Diet-induced obesity (DIO) reduces fatty acid oxidation in skeletal muscle and decreases circulating levels of adiponectin. Endocannabinoid signaling is overactive in obesity, with some effects abated by antagonism of cannabinoid receptor 1 (CB1). This research aimed to determine if treatment with the global CB1 antagonist/inverse agonist, AM251, in high-fat diet (HFD) fed rats influenced adiponectin signaling in skeletal muscle and a "browning" of white adipose tissue (WAT) defined by UCP1 expression levels. Male Sprague Dawley rats consumed an HFD (21% fat) for 9 weeks before receiving daily intraperitoneal injections with vehicle or AM251 (3 mg/kg) for 6 weeks. mRNA expression of genes involved in metabolic functions were measured in skeletal muscle and adipose tissue, and blood was harvested for the measurement of hormones and cytokines. Muscle citrate synthase activity was also measured. AM251 treatment decreased fat pad weight (epididymal, peri-renal, brown), and plasma levels of leptin, glucagon, ghrelin, and GLP-1, and increased PAI-1 along with a range of pro-inflammatory and anti-inflammatory cytokines; however, AM251 did not alter plasma adiponectin levels, skeletal muscle citrate synthase activity or mRNA expression of the genes measured in muscle. AM251 treatment had no effect on white fat UCP1 expression levels. AM251 decreased fat pad mass, altered plasma hormone levels, but did not induce browning of WAT defined by UCP1 mRNA levels or alter gene expression in muscle treated acutely with adiponectin, demonstrating the complexity of the endocannabinoid system and metabolism. The CB1 ligand AM251 increased systemic inflammation suggesting limitations on its use in metabolic disorders.

Seasonal Change in Body Composition and Physique of Team Sport Athletes.

ABSTRACT: Walker, EJ, Aughey, RJ, McLaughlin, P, and McAinch, AJ. Seasonal change in body composition and physique of team sport athletes. J Strength Cond Res 36(2): 565-572, 2022-Body composition of team sport athletes was measured at 3 points across the preseason and competitive season. This repeated-measures study was conducted in 46 professional Australian football (AF) (age 23.8 ± 3.8 years), 26 soccer (age 22.7 ± 4.7 years), and 33 rugby union players (age 28.1 ± 4.2 years). A mixed-design analysis of variance was used to determine change across the season, and Pearson's correlation was used to determine the relationship between different measures. Anthropometry, dual-energy x-ray absorptiometry (DXA), and 3-dimensional (3D) scan technology were used in AF and soccer, whereas only DXA was used in rugby. Body mass remained unchanged for both AF and soccer with gains in lean mass (p < 0.01), from preseason to early in the competitive season. Skinfold measures declined in AF (p < 0.001) and soccer (p < 0.05) across the season, whereas DXA-measured fat mass only declined in soccer (p < 0.01). Rugby backs (p < 0.01) and forwards (p < 0.001) reduced body fat and gained lean mass from preseason to in-season with forwards having greater relative and absolute changes as measured by DXA. 3D technology did not show change across the season. Dual-energy x-ray absorptiometry body fat percent and the sum of skinfold correlation were large (r = 0.74 [p < 0.001, CI 0.67-0.81]). The greatest change in body composition occurs from the beginning of preseason to the start of competition, with changes returning to baseline levels toward the end of season. Dual-energy x-ray absorptiometry and skinfold measures were moderately correlated, providing a good alternative to track change in subcutaneous fat in AF and soccer athletes.

Sex-Specific Differences in Lysine, 3-Hydroxybutyric Acid and Acetic Acid in Offspring Exposed to Maternal and Postnatal High Linoleic Acid Diet, Independent of Diet.

BACKGROUND: Linoleic acid (LA) is an essential polyunsaturated fatty acid (PUFA) that is required for foetal growth and development. Excess intake of LA can be detrimental for metabolic health due to its pro-inflammatory properties; however, the effect of a diet high in LA on offspring metabolites is unknown. In this study, we aimed to determine the role of maternal or postnatal high linoleic acid (HLA) diet on plasma metabolites in adult offspring. METHODS: Female Wistar Kyoto (WKY) rats were fed with either low LA (LLA) or HLA diet for 10 weeks prior to conception and during gestation/lactation. Offspring were weaned at postnatal day 25 (PN25), treated with either LLA or HLA diets and sacrificed at PN180. Metabolite analysis was performed in plasma samples using Nuclear Magnetic Resonance. RESULTS: Maternal and postnatal HLA diet did not alter plasma metabolites in male and female adult offspring. There was no specific clustering among different treatment groups as demonstrated by principal component analysis. Interestingly, there was clustering among male and female offspring independent of maternal and postnatal dietary intervention. Lysine was higher in female offspring, while 3-hydroxybutyric acid and acetic acid were significantly higher in male offspring. CONCLUSION: In summary, maternal or postnatal HLA diet did not alter the plasma metabolites in the adult rat offspring; however, differences in metabolites between male and female offspring occurred independently of dietary intervention.

Maternal and Postnatal High Linoleic Acid Diet Impacts Lipid Metabolism in Adult Rat Offspring in a Sex-Specific Manner.

Linoleic acid (LA), an n-6 polyunsaturated fatty acid (PUFA), is essential for fetal growth and development. We aimed to investigate the effect of maternal and postnatal high LA (HLA) diet on plasma FA composition, plasma and hepatic lipids and genes involved in lipid metabolism in the liver of adult offspring. Female rats were fed with low LA (LLA; 1.44% LA) or HLA (6.21% LA) diets for 10 weeks before pregnancy, and during gestation/lactation. Offspring were weaned at postnatal day 25 (PN25), fed either LLA or HLA diets and sacrificed at PN180. Postnatal HLA diet decreased circulating total n-3 PUFA and alpha-linolenic acid (ALA), while increased total n-6 PUFA, LA and arachidonic acid (AA) in both male and female offspring. Maternal HLA diet increased circulating leptin in female offspring, but not in males. Maternal HLA diet decreased circulating adiponectin in males. Postnatal HLA diet significantly decreased aspartate transaminase (AST) in females and downregulated total cholesterol, HDL-cholesterol and triglycerides in the plasma of males. Maternal HLA diet downregulated the hepatic mRNA expression of Hmgcr in both male and female offspring and decreased the hepatic mRNA expression of Cpt1a and Acox1 in females. Both maternal and postnatal HLA diet decreased hepatic mRNA expression of Cyp27a1 in females. Postnatal diet significantly altered circulating fatty acid concentrations, with sex-specific differences in genes that control lipid metabolism in the adult offspring following exposure to high LA diet in utero.

Pregnancy and diet-related changes in the maternal gut microbiota following exposure to an elevated linoleic acid diet.

Dietary intakes of linoleic acid (LA) have increased, including in women of reproductive age. Changes in maternal gut microbiome have been implicated in the metabolic adaptions that occur during pregnancy. We aimed to investigate whether consumption of a diet with elevated LA altered fecal microbiome diversity before and during pregnancy. Female Wistar-Kyoto rats consumed a high-LA diet (HLA: 6.21% of energy) or a low-LA diet (LLA: 1.44% of energy) for 10 wk before mating and during pregnancy. DNA was isolated from fecal samples before pregnancy [embryonic day 0 (E0)], or during pregnancy at E10 and E20. The microbiome composition was assessed with 16S rRNA sequencing. At E0, the beta-diversity of LLA and HLA groups differed with HLA rats having significantly lower abundance of the genera Akkermansia, Peptococcus, Sutterella, and Xo2d06 but higher abundance of Butyricimonas and Coprococcus. Over gestation, in LLA but not HLA rats, there was a reduction in alpha-diversity and an increase in beta-diversity. In the LLA group, the abundance of Akkermansia, Blautia, rc4.4, and Streptococcus decreased over gestation, whereas Coprococcus increased. In the HLA group; only the abundance of Butyricimonas decreased. At E20, there were no differences in alpha- and beta-diversity, and the abundance of Roseburia was significantly increased in the HLA group. In conclusion, consumption of a HLA diet alters gut microbiota composition, as does pregnancy in rats consuming a LLA diet. In pregnancy, consumption of a HLA diet does not alter gut microbiota composition.

Role of omega-6 and omega-3 fatty acids in fetal programming.

Maternal nutrition plays a critical role in fetal development and can influence adult onset of disease. Linoleic acid (LA) and alpha-linolenic acid (ALA) are major omega-6 (n-6) and n-3 polyunsaturated fatty acids (PUFA), respectively, that are essential in our diet. LA and ALA are critical for the development of the fetal neurological and immune systems. However, in recent years, the consumption of n-6 PUFA has increased gradually worldwide, and elevated n-6 PUFA consumption may be harmful to human health. Consumption of diets with high levels of n-6 PUFA before or during pregnancy may have detrimental effects on fetal development and may influence overall health of offspring in adulthood. This review discusses the role of n-6 PUFA in fetal programming, the importance of a balance between n-6 and n-3 PUFAs in the maternal diet, and the need of further animal models and human studies that critically evaluate both n-6 and n-3 PUFA contents in diets.

The Role of Atypical Cannabinoid Ligands O-1602 and O-1918 on Skeletal Muscle Homeostasis with a Focus on Obesity.

O-1602 and O-1918 are atypical cannabinoid ligands for GPR55 and GPR18, which may be novel pharmaceuticals for the treatment of obesity by targeting energy homeostasis regulation in skeletal muscle. This study aimed to determine the effect of O-1602 or O-1918 on markers of oxidative capacity and fatty acid metabolism in the skeletal muscle. Diet-induced obese (DIO) male Sprague Dawley rats were administered a daily intraperitoneal injection of O-1602, O-1918 or vehicle for 6 weeks. C2C12 myotubes were treated with O-1602 or O-1918 and human primary myotubes were treated with O-1918. GPR18 mRNA was expressed in the skeletal muscle of DIO rats and was up-regulated in red gastrocnemius when compared with white gastrocnemius. O-1602 had no effect on mRNA expression on selected markers for oxidative capacity, fatty acid metabolism or adiponectin signalling in gastrocnemius from DIO rats or in C2C12 myotubes, while APPL2 mRNA was up-regulated in white gastrocnemius in DIO rats treated with O-1918. In C2C12 myotubes treated with O-1918, PGC1α, NFATc1 and PDK4 mRNA were up-regulated. There were no effects of O-1918 on mRNA expression in human primary myotubes derived from obese and obese T2DM individuals. In conclusion, O-1602 does not alter mRNA expression of key pathways important for skeletal muscle energy homeostasis in obesity. In contrast, O-1918 appears to alter markers of oxidative capacity and fatty acid metabolism in C2C12 myotubes only. GPR18 is expressed in DIO rat skeletal muscle and future work could focus on selectively modulating GPR18 in a tissue-specific manner, which may be beneficial for obesity-targeted therapies.

Elevated maternal linoleic acid reduces circulating leptin concentrations, cholesterol levels and male fetal survival in a rat model.

KEY POINTS: Linoleic acid consumption is increasing in Western populations. We investigated whether elevated linoleic acid in pregnancy was deleterious to mothers or offspring. Maternal and fetal body and organ weights were not affected by elevated linoleic acid consumption. Maternal lipids and leptin were altered following elevated linoleic acid consumption. Male offspring numbers were reduced following elevated linoleic acid consumption. ABSTRACT: Dietary intakes of linoleic acid (LA) have increased dramatically in Western populations, including in women of reproductive age. Pro-inflammatory effects of LA may have detrimental effects on maternal and offspring outcomes. We aimed to investigate whether consumption of a maternal diet with elevated LA altered maternal inflammatory or metabolic markers during pregnancy, fetal growth and/or the sex ratio of the offspring. Female Wistar Kyoto rats consumed a diet high in LA (HLA) (6.21% of energy) or a diet low in LA (LLA) (1.44% of energy) for 10 weeks prior to mating and during pregnancy. Pregnant rats were killed at embryonic day 20 (E20). There were no differences in maternal or fetal body weights or organ weights in the HLA group compared to the LLA group. There was no difference in maternal circulating cytokine concentrations between dietary groups. In the maternal liver, IL-1α concentrations were significantly lower, and TNF-α and IL-7 significantly higher in the HLA group. Total plasma cholesterol, LDL-cholesterol, HDL cholesterol and the total:HDL cholesterol ratio were lower in dams fed the HLA diet. mRNA expression of sterol regulatory element binding transcription factor 1 (SREBF-1) and leptin in maternal adipose tissue was lower in the HLA group, as were circulating leptin concentrations. The proportion of male fetuses was lower and circulating prostaglandin E metabolite concentrations were increased in the HLA group. In conclusion, consumption of a maternal diet high in linoleic acid alters cholesterol metabolism and prostaglandin E metabolite concentrations, which may contribute to the reduced proportion of male offspring.

Linoleic Acid Increases Prostaglandin E2 Release and Reduces Mitochondrial Respiration and Cell Viability in Human Trophoblast-Like Cells.

BACKGROUND/AIMS: The omega 6 fatty acid (FA) linoleic acid (LA) is required for embryonic development; however, omega 6 FAs can alter cellular metabolism via inflammation or modulation of mitochondrial function. Fetal LA is obtained from the maternal diet, and FAs are transported to the fetus via placental FA transporters (FATPs) and binding proteins (FABPs), but specific proteins responsible for LA transport in placental trophoblasts are unknown. Dietary LA consumption is increasing, but the effect of elevated LA on trophoblast function is not clear. METHODS: Swan71 trophoblasts were exposed to physiological and supraphysiological concentrations of LA for 24 hours. Quantification of mRNA was determined using real time PCR, and protein concentration was determined by Western blot analysis. Cell viability, citrate synthase activity and mitochondrial respiration were determined. RESULTS: Exposure to 300 and 500 µM LA increased FATP1 and FATP4 mRNA expression. 500 µM LA increased FATP1 and FATP4 protein expression. Exposure to 500 µM increased FABP5 mRNA expression, while exposure to 100 to 500 µM LA decreased FABP3 mRNA expression. 300 and 500 µM LA decreased FABP3 protein expression. Cell viability was decreased by exposure to LA (100 to 1000 µM). Citrate synthase activity and routine mitochondrial respiration were significantly decreased by exposure to 300 and 500 µM LA, and maximal respiration and spare respiratory capacity were decreased by exposure to 100 to 500 µM LA. 300 and 500 µM LA increased reactive oxygen species generation in human trophoblasts. Moreover, exposure to 300 and 500 µM LA decreased IL-6 secretion. Exposure to 500 µM LA increased IL-8, NF-κB and PPAR-γ mRNA expression, but decreased NF-κB protein expression. 300 µM LA decreased IL-8 protein expression. Further, exposure to 100 to 500 µM LA increased prostaglandin E2 and leukotriene B4 release. CONCLUSION: Exposure to LA decreases cell viability, alters mRNA expression of FA transport related proteins, mitochondrial respiration and function, and inflammatory responses in trophoblasts. These findings may have implications on placental function when women consume high levels of LA.

Uteroplacental insufficiency reduces rat plasma leptin concentrations and alters placental leptin transporters: ameliorated with enhanced milk intake and nutrition.

KEY POINTS: Uteroplacental insufficiency compromises maternal mammary development, milk production and pup organ development; this is ameliorated by cross-fostering, which improves pup growth and organ development and prevents adult diseases in growth-restricted (Restricted) offspring by enhancing postnatal nutrition. Leptin is transported to the fetus from the mother by the placenta; we report reduced plasma leptin concentrations in Restricted fetuses associated with sex-specific alterations in placental leptin transporter expression. Pup plasma leptin concentrations were also reduced during suckling, which may suggest reduced milk leptin transport or leptin reabsorption. Mothers suckled by Restricted pups had impaired mammary development and changes in milk fatty acid composition with no alterations in milk leptin; cross-fostering restored pup plasma leptin concentrations, which may be correlated to improved milk composition and intake. Increased plasma leptin and altered milk fatty acid composition in Restricted pups suckling mothers with normal lactation may improve postnatal growth and prevent adult diseases. ABSTRACT: Uteroplacental insufficiency reduces birth weight and adversely affects fetal organ development, increasing adult disease risk. Cross-fostering improves postnatal nutrition and restores these deficits. Mothers with growth-restricted pups have compromised milk production and composition; however, the impact cross-fostering has on milk production and composition is unknown. Plasma leptin concentrations peak during the completion of organogenesis, which occurs postnatally in rats. Leptin is transferred to the fetus via the placenta and to the pup via the lactating mammary gland. This study investigated the effect of uteroplacental insufficiency on pup plasma leptin concentrations and placental leptin transporters. We additionally examined whether cross-fostering improves mammary development, milk composition and pup plasma leptin concentrations. Fetal growth restriction was induced by bilateral uterine vessel ligation surgery on gestation day 18 in Wistar Kyoto rats (termed uteroplacental insufficiency surgery mothers). Growth-restricted (Restricted) fetuses had reduced plasma leptin concentrations, persisting throughout lactation, and sex-specific alterations in placental leptin transporters. Mothers suckled by Restricted pups had impaired mammary development, altered milk fatty acid composition and increased plasma leptin concentrations, despite no changes in milk leptin. Milk intake was reduced in Restricted pups suckling uteroplacental insufficiency surgery mothers compared to Restricted pups suckling sham-operated mothers. Cross-fostering Restricted pups onto a sham-operated mother improved postnatal growth and restored plasma leptin concentrations compared to Restricted pups suckling uteroplacental insufficiency surgery mothers. Uteroplacental insufficiency alters leptin homeostasis. This is ameliorated with cross-fostering and enhanced milk fatty acid composition and consumption, which may protect the pups from developing adverse health conditions in adulthood.

Cannabinoid receptors in the kidney.

PURPOSE OF REVIEW: The endocannabinoid system modulates cell signaling targets that are essential for energy homeostasis. Endocannabinoids bind to G protein-coupled receptors in the central nervous system and periphery, including the kidney. Modulation of cannabinoid receptor 1 (CB1) and CB2 activity in the kidney in diabetes and obesity has been identified as potential therapeutic target to reduce albuminuria and renal fibrosis. This review will highlight the results of recent studies that have identified a role for CB1 and CB2 in normal and pathological renal conditions. RECENT FINDINGS: CB1 and CB2 have been reported to play key roles in renal function and dysfunction. Recent studies have determined that antagonism of CB1 and agonism of CB2 in diabetic nephropathy and obesity associated kidney disease can reduce albuminuria, potentially by acting on both the glomeruli and tubules. Emerging studies have also identified a role for CB1 in renal diseases associated with fibrosis, with CB1 upregulated in multiple models of human nephropathies. SUMMARY: Emerging studies using isolated cells, rodent models, and human studies have identified a critical role for the endocannabinoid system in renal function and disease. Thus, therapeutics that modulate the activity of CB1 and CB2 in renal disease could become clinically relevant.