Metabolic effect of adrenaline infusion in people with type 1 diabetes and healthy individuals.

AIMS/HYPOTHESIS: As a result of early loss of the glucagon response, adrenaline is the primary counter-regulatory hormone in type 1 diabetes. Diminished adrenaline responses to hypoglycaemia due to counter-regulatory failure are common in type 1 diabetes, and are probably induced by exposure to recurrent hypoglycaemia, however, the metabolic effects of adrenaline have received less research attention, and also there is conflicting evidence regarding adrenaline sensitivity in type 1 diabetes. Thus, we aimed to investigate the metabolic response to adrenaline and explore whether it is modified by prior exposure to hypoglycaemia. METHODS: Eighteen participants with type 1 diabetes and nine healthy participants underwent a three-step ascending adrenaline infusion during a hyperinsulinaemic-euglycaemic clamp. Continuous glucose monitoring data obtained during the week before the study day were used to assess the extent of hypoglycaemia exposure. RESULTS: While glucose responses during the clamp were similar between people with type 1 diabetes and healthy participants, plasma concentrations of NEFAs and glycerol only increased in the group with type 1 diabetes (p<0.001). Metabolomics revealed an increase in the most common NEFAs (p<0.01). Other metabolic responses were generally similar between participants with type 1 diabetes and healthy participants. Exposure to hypoglycaemia was negatively associated with the NEFA response; however, this was not statistically significant. CONCLUSIONS/INTERPRETATION: In conclusion, individuals with type 1 diabetes respond with increased lipolysis to adrenaline compared with healthy participants by mobilising the abundant NEFAs in plasma, whereas other metabolic responses were similar. This may suggest that the metabolic sensitivity to adrenaline is altered in a pathway-specific manner in type 1 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov NCT05095259.

Increased molar ratio of free fatty acids to albumin in blood as cause and early biomarker for the development of cataracts and Alzheimer's disease.

Cataracts and Alzheimer's disease (AD) are closely linked and are associated with aging and with systemic diseases that increase the molar ratio of free fatty acids to albumin (mFAR) in the blood. From the results of our earlier studies on the development of senile cataracts and from results recently published in the literature on the pathogenesis of Alzheimer's disease, we suggest that there is a common lipotoxic cascade for both diseases, explaining the strong connection between aging, an elevated mFAR in the blood, cataract formation, and AD. Long-chain free fatty acids (FFA) are transported in the blood as FFA/albumin complexes. In young people, vascular albumin barriers in the eyes and brain, very similar in their structure and effect, reduce the FFA/albumin complex concentration from around 650 µmol/l in the blood to 1-3 µmol/l in the aqueous humour of the eyes as well as in the cerebrospinal fluid of the brain. At such low concentrations the fatty acid uptake of the target cells - lens epithelial and brain cells - rises with increasing FFA/albumin complex concentrations, especially when the fatty acid load of albumin molecules is mFAR>1. At higher albumin concentrations, for instance in blood plasma or the interstitial tissue spaces, the fatty acid uptake of the target cells becomes increasingly independent of the FFA/albumin complex concentration and is mainly a function of the mFAR (Richieri et al., 1993). In the blood plasma of young people, the mFAR is normally below 1.0. In people over 40 years old, aging increases the mFAR by decreasing the plasma concentration of albumin and enhancing the plasma concentrations of FFA. The increase in the mFAR in association with C6-unsaturated FFA are risk factors for the vascular albumin barriers (Hennig et al., 1984). Damage to the vascular albumin barrier in the eyes and brain increases the concentration of FFA/albumin complex in the aqueous humour as well as in the cerebrospinal fluid, leading to mitochondrial dysfunction and the death of lens epithelial and brain cells, the development of cataracts, and AD. An age-dependent increase in the concentration of FFA/albumin complex has been found in the aqueous humour of 177 cataract patients, correlating with the mitochondria-mediated apoptotic death of lens epithelial cells, lens opacification and cataracts (Iwig et al., 2004). Mitochondrial dysfunction is also an early crucial event in Alzheimer's pathology, closely connected with the generation of amyloid beta peptides (Leuner et al., 2012). Very recently, amyloid beta production has also been confirmed in the lenses of Alzheimer's patients, causing cataracts (Moncaster et al., 2022). In view of this, we propose that there is a common lipotoxic cascade for senile cataract formation and senile AD, initiated by aging and/or systemic diseases, leading to an mFAR>1 in the blood.

High-fat diet consumption promotes adolescent neurobehavioral abnormalities and hippocampal structural alterations via microglial overactivation accompanied by an elevated serum free fatty acid concentration.

Mounting evidence suggests that high-fat diet (HFD) consumption increases the risk for depression, but the neurophysiological mechanisms involved remain to be elucidated. Here, we demonstrated that HFD feeding of C57BL/6J mice during the adolescent period (from 4 to 8 weeks of age) resulted in increased depression- and anxiety-like behaviors concurrent with changes in neuronal and myelin structure in the hippocampus. Additionally, we showed that hippocampal microglia in HFD-fed mice assumed a hyperactive state concomitant with increased PSD95-positive and myelin basic protein (MBP)-positive inclusions, implicating microglia in hippocampal structural alterations induced by HFD consumption. Along with increased levels of serum free fatty acids (FFAs), abnormal deposition of lipid droplets and increased levels of HIF-1α protein (a transcription factor that has been reported to facilitate cellular lipid accumulation) within hippocampal microglia were observed in HFD-fed mice. The use of minocycline, a pharmacological suppressor of microglial overactivation, effectively attenuated neurobehavioral abnormalities and hippocampal structural alterations but barely altered lipid droplet accumulation in the hippocampal microglia of HFD-fed mice. Coadministration of triacsin C abolished the increases in lipid droplet formation, phagocytic activity, and ROS levels in primary microglia treated with serum from HFD-fed mice. In conclusion, our studies demonstrate that the adverse influence of early-life HFD consumption on behavior and hippocampal structure is attributed at least in part to microglial overactivation that is accompanied by an elevated serum FFA concentration and microglial aberrations represent a potential preventive and therapeutic target for HFD-related emotional disorders.

Pioglitazone reduces serum ketone bodies in sodium-glucose cotransporter-2 inhibitor-treated non-obese type 2 diabetes: A single-centre, randomized, crossover trial.

AIM: To examine the effects of the thiazolidinedione (TZD) pioglitazone on reducing ketone bodies in non-obese patients with T2DM treated with the sodium-glucose cotransporter-2 (SGLT2) inhibitor canagliflozin. METHODS: Crossover trials with two periods, each treatment period lasting 4 weeks, with a 4-week washout period, were conducted. Participants were randomly assigned in a 1:1 ratio to receive pioglitazone combined with canagliflozin (PIOG + CANA group) versus canagliflozin monotherapy (CANA group). The primary outcome was change (Δ) in ß-hydroxybutyric acid (ß-HBA) before and after the CANA or PIOG + CANA treatments. The secondary outcomes were Δchanges in serum acetoacetate and acetone, the rate of conversion into urinary ketones, and Δchanges in factors related to SGLT2 inhibitor-induced ketone body production including non-esterified fatty acids (NEFAs), glucagon, glucagon to insulin ratio, and noradrenaline (NA). Analyses were performed in accordance with the intention-to-treat principle. RESULTS: Twenty-five patients with a mean age of 49 ± 7.97 years and a body mass index of 25.35 ± 2.22 kg/m2 were included. One patient discontinued the study during the washout period. Analyses revealed a significant increase in the levels of serum ketone bodies and an elevation in the rate of conversion into urinary ketones after both interventions. However, differernces in levels of ketone bodies (except for acetoacetate) in the PIOG + CANA group were significantly smaller than in the CANA group (219.84 ± 80.21 µmol/L vs. 317.69 ± 83.07 µmol/L, p < 0.001 in ß-HBA; 8.98 ± 4.17 µmol/L vs. 12.29 ± 5.27 µmol/L, p = 0.018 in acetone). NEFA, glucagon, glucagon to insulin ratio, and NA were also significantly increased after both CANA and PIOG + CANA treatments; while only NEFAs demonstrated a significant difference between the two groups. Correlation analyses revealed a significant association between the difference in Δchanges in serum NEFA levels with the differences in Δchanges in ketones of ß-HBA and acetoacetate. CONCLUSION: Supplementation of pioglitazone could alleviate canagliflozin-induced ketone bodies. This benefit may be closely associated with decreased substrate NEFAs rather than other factors including glucagon, fasting insulin and NA.

The abnormalities of free fatty acid metabolism in patients with hypertrophic cardiomyopathy, a single-center retrospective observational study.

BACKGROUND: Previous studies have shown the importance of energy deficiency and malfunctioning mitochondria in the pathophysiology of hypertrophic cardiomyopathy (HCM). There has been a little research into the relationship between plasma free fatty acids (FFA), one of the heart's main energy sources, and HCM. We evaluated its clinical importance in HCM to see if there was a link between plasma FFA metabolism and HCM. METHODS: In a single-center retrospective observational study, we investigated 420 HCM patients diagnosed at Beijing Anzhen Hospital between January 1, 2018, and December 31, 2022. Meanwhile, 1372 individuals without HCM (non-HCM) were recruited. 391 non-HCM patients were chosen as controls via a propensity score matching (PSM) study with a 1:1 ratio. RESULTS: FFA in HCM patients showed statistically significant correlations with creatinine (r = 0.115, p = 0.023), estimated GFR (r=-0.130, p = 0.010), BNP (r = 0.152, p = 0.007), LVEF (r=-0.227, p < 0.001), LVFS (r=-0.160, p = 0.002), and LAD (r = 0.112, p = 0.028). Higher FFA levels were found in HCM patients who had atrial fibrillation and NYHY functional classes III or IV (p = 0.015 and p = 0.022, respectively). In HCM patients, multiple linear regression analysis revealed that BNP and LVEF had independent relationships with increasing FFA (Standardized = 0.139, p = 0.013 and =-0.196, p < 0.001, respectively). CONCLUSIONS: Among HCM patients, the plasma FFA concentration was lower, and those with AF and NYHY functional class III or IV had higher FFA levels, and LVEF and BNP were independently associated with increasing FFA. The findings of the study should help inspire future efforts to better understand how energy deficiency contributes to hypertrophic cardiomyopathy (HCM) development.

Variations of blood metabolites in single- and multiple-bearing Ossimi ewes during the transition period.

Evaluation of the metabolic profile indices allows early detection and treatment of various metabolic disorders during the transition period in ewes. This study aimed to determine the variations in the blood metabolites around lambing in Ossimi ewes. The blood metabolites were investigated in ewes with single (n = 27) and multiple (n = 9) lambs at 3- and 1-week pre-lambing and 3-week post-lambing. The plasma concentrations of glucose were higher in single-bearing ewes than those in multiple-bearing ewes (p < .05), moreover, its lowest value was measured at 1-week prepartum in both groups. Throughout the study period, the serum concentrations of non-esterified fatty acids (NEFA) were significantly increased in ewes with multiple lambs compared to ewes with single lambs (p < .05), and the highest value was found at 1-week before parturition in both groups. In addition, the serum level of beta-hydroxybutyric acid (BHBA) was higher at 3-week postpartum, and it was significantly increased in multiple-bearing ewes than that in single-bearing ones (p < .05) at 3-week pre-lambing. In both groups, the lowest values of total proteins were determined 1-week before lambing, and its concentrations, at 3- and 1-week prepartum, were higher in ewes with single lambs than those with multiple lambs (p < .05). In contrast, the serum concentrations of albumin were significantly lowered 1-week postpartum (p < .05), and without significant differences between both groups (p > .05). The serum activities of aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT) were significantly increased at 1-week after parturition in both groups (p < .05). Furthermore, the serum activities of AST were higher in multiple-bearing ewes than those in single-bearing ones at 3-week pre-lambing and 3-week post-lambing (p < .05). Variable positive and negative correlations were determined among the blood metabolites. In conclusion, physiological adaptations are associated with the fluctuation of the blood metabolites around lambing. The higher the number of foetuses the higher the metabolic variations in Ossimi ewes. Therefore, regular metabolic profiling for health monitoring may be necessary to avoid disease development during the transition period.

Association between metabolic parameters and embryo production in superovulated dairy cattle.

This study aims to investigate the relationship between metabolic parameters and the number of embryos produced in superovulated cows with high genetic characteristics in milk yield. Eighteen Holstein donors were treated with classic superovulation protocols, AI and flushing. During superovulation, decreasing doses of FSH (follicle-stimulating hormone) were administered at 12-h intervals for 4 days. Plasma insulin-like growth factor (IGF1), glucose (GLU), beta-hydroxybutyric acid (BHB), non-esterified fatty acid (NEFA), blood urea nitrogen (BUN) and total protein (TP) levels were determined by using an autoanalyzer. The mixed model analysis of variance was used for statistical analysis. As a result, plasma IGF1, BHB and BUN had significant interactions with both groups and days (p < .05). Additionally, plasma TP-days interactions were significant (p < .05). Furthermore, there was a negative correlation between the number of embryos and plasma BHB levels (p < .05). In conclusion, under appropriate environmental conditions, metabolic profile control of donors can contribute to the embryo production process and to the studies on the metabolic infrastructure.

Effects of acute and chronic stair-climbing exercise on metabolic health: A systematic review.

Stair climbing exercise (SE) provides a feasible approach to elevate physical activity, but the effects on metabolic health are unclear. We systematically reviewed the currently available evidence on the effects of SE on fasting and postprandial glycaemia and lipidaemia. Studies were included if they investigated the effects of acute or chronic (at least 2 weeks) SE on fasting and/or postprandial glycaemic (insulin and glucose) and lipidaemic (triacylglycerols and non-esterified fatty acids) responses in healthy, prediabetic or type 2 diabetic adult populations. PubMed, Web of Science and Scopus were searched for eligible studies until July 2022. A total of 25 studies (14 acute and 11 chronic) were eligible for review. Acute bout(s) of SE can reduce postprandial glycaemia in individuals with prediabetes and type 2 diabetes (8 of 9 studies), but not in normoglycemic individuals. The effects of acute SE on postprandial lipidaemic responses and SE training on both fasting and postprandial glycaemia/lipidaemia were unclear. Acute SE may reduce postprandial glucose concentrations in people with impaired glycaemic control, but high-quality studies are needed. More studies are needed to determine the effect of chronic SE training on postprandial glucose and lipid responses, and the acute effects of SE on lipid responses.

Relationship of circulating levels of long-chain fatty acids to persistent organ failure in acute pancreatitis.

During acute pancreatitis (AP), free fatty acids (FFAs) are liberated from circulating triglycerides (TG) and injured adipocytes by pancreatic lipase. Circulating FFAs have been suspected as a source of systemic lipotoxicity in AP. However, assessment of FFAs is difficult and time-consuming, and little is known about relative levels of FFAs between patients with different severities of AP and controls. This study's aims were to assess early circulating levels of FFAs, (both saturated and unsaturated) in patients with AP vs. controls, and associations between FFA levels and AP severity. Serum samples from patients with AP were collected at enrollment (day 1 of hospital stay); serum samples were also collected from controls. FFAs including palmitic, palmitoleic, stearic, oleic, and linoleic acid were extracted and quantitated using gas chromatography separation. Severity of AP was determined by Revised Atlanta Classification. Differences in FFA levels and percentages of total FFAs were assessed between patients with AP and controls and patients with AP of different severity grades. A total of 93 patients with AP (48 female, 52%) and 29 controls (20 female, 69%) were enrolled. Of the patients with AP, 74 had mild/moderate and 19 had severe AP. Serum levels of all FFAs except stearic acid were significantly higher in patients with AP compared with controls. A strong and independent association between elevated palmitoleic acid levels and severe AP was found. Serum unsaturated FFA levels, specifically palmitoleic acid, appear to correlate with severe AP. These findings have potential clinical implications for targeted AP therapies.NEW & NOTEWORTHY Drivers of the inflammatory response in acute pancreatitis remain incompletely understood. Unsaturated fatty acids, specifically palmitoleic, appear to have an association with more severe acute pancreatitis. This finding presents a new clinical understanding of fatty acid toxicity and highlights a potential future target for treatment in severe acute pancreatitis.

A randomized controlled trial investigating the effect of transport duration and age at transport on surplus dairy calves: Part II. Impact on hematological variables.

Surplus dairy calves often arrive at veal and dairy-beef rearing facilities with health and blood metabolite level abnormalities, which can affect their welfare and performance, predisposing them to future health challenges. The objective of this randomized controlled trial was to investigate the effects of transport duration and age at the time of transport on blood parameters in surplus dairy calves following 6, 12, or 16 h of continuous road transportation. All surplus calves from 5 commercial dairy farms in Ontario were enrolled and examined daily before transport (n = 175). On the day of transportation, calves were weighed, blood sampled, and randomly assigned to 6, 12, or 16 h of transportation. Blood samples were then collected immediately after transportation, as well as 24, 48, and 72 h thereafter. Serum was analyzed at a provincial diagnostic laboratory for nonesterified fatty acids (NEFA), ß-hydroxybutyric acid (BHBA), creatine kinase (CK), cholesterol, and haptoglobin. In addition, blood gas and electrolyte values were also assessed at the time of sample collection. Mixed models with repeated measures were used to assess the effects of transport duration, breed, sex, transfer of passive immunity status, weight before transportation, and age at transportation on blood parameters. Immediately following transportation, NEFA and BHBA were greater for calves transported for 12 h (Δ = 0.22 mmol/L NEFA, 95% CI = 0.15 to 0.30; Δ = 0.04 mmol/L BHBA, 95% CI = 0.02 to 0.06) and 16 h (Δ = 0.35 mmol/L NEFA, 95% CI = 0.27 to 0.42; Δ = 0.10 mmol/L BHBA, 95% CI = 0.08 to 0.11) compared with calves transported for 6 h. Glucose was lower immediately following transportation in calves transported for 16 h compared with 6 h (Δ = -15.54 mg/dL, 95% CI = -21.54 to -9.54). In addition, pH and HCO3- were lower in calves transported for 12 (Δ = -0.09 pH, 95% CI = -0.13 to -0.05; Δ = -1.59 mmol/L HCO3-, 95% CI = -2.61 to -0.56) and 16 h (Δ = -0.07 pH, 95% CI = -0.12 to -0.03; Δ = -1.95 mmol/L HCO3-, 95% CI = -2.95 to -0.95) compared with calves transported for 6 h. Calves transported between 15 and 19 d of age had a higher concentration of cholesterol and CK (Δ = 0.27 mmol/L cholesterol; 37.18 U/L CK) compared with 2- to 6-d-old calves, and calves 12 to 14 d old had greater reduction in HCO3- (Δ = -0.92 mmol/L) compared with 2- to 6-d-old calves. These findings show that transporting calves for long distances results in lower glucose concentration and suboptimal energy status, and that this effect varies based on the calf's age.

Exposure to environmental contaminants is associated with altered hepatic lipid metabolism in non-alcoholic fatty liver disease.

BACKGROUND & AIMS: Recent experimental models and epidemiological studies suggest that specific environmental contaminants (ECs) contribute to the initiation and pathology of non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanisms linking EC exposure with NAFLD remain poorly understood and there is no data on their impact on the human liver metabolome. Herein, we hypothesized that exposure to ECs, particularly perfluorinated alkyl substances (PFAS), impacts liver metabolism, specifically bile acid metabolism. METHODS: In a well-characterized human NAFLD cohort of 105 individuals, we investigated the effects of EC exposure on liver metabolism. We characterized the liver (via biopsy) and circulating metabolomes using 4 mass spectrometry-based analytical platforms, and measured PFAS and other ECs in serum. We subsequently compared these results with an exposure study in a PPARa-humanized mouse model. RESULTS: PFAS exposure appears associated with perturbation of key hepatic metabolic pathways previously found altered in NAFLD, particularly those related to bile acid and lipid metabolism. We identified stronger associations between the liver metabolome, chemical exposure and NAFLD-associated clinical variables (liver fat content, HOMA-IR), in females than males. Specifically, we observed PFAS-associated upregulation of bile acids, triacylglycerols and ceramides, and association between chemical exposure and dysregulated glucose metabolism in females. The murine exposure study further corroborated our findings, vis-à-vis a sex-specific association between PFAS exposure and NAFLD-associated lipid changes. CONCLUSIONS: Females may be more sensitive to the harmful impacts of PFAS. Lipid-related changes subsequent to PFAS exposure may be secondary to the interplay between PFAS and bile acid metabolism. LAY SUMMARY: There is increasing evidence that specific environmental contaminants, such as perfluorinated alkyl substances (PFAS), contribute to the progression of non-alcoholic fatty liver disease (NAFLD). However, it is poorly understood how these chemicals impact human liver metabolism. Here we show that human exposure to PFAS impacts metabolic processes associated with NAFLD, and that the effect is different in females and males.

Pathophysiology and Biomarker Potential of Fatty Acid Ethyl Ester Elevation During Alcoholic Pancreatitis.

BACKGROUND & AIMS: The role of fatty acid ethyl esters (FAEEs) during human alcoholic pancreatitis is unknown. We compared FAEEs levels with their nonesterified fatty acids (NEFAs) precursors during alcohol intoxication and clinical alcoholic pancreatitis. The pathophysiology underlying FAEEs increase and their role as diagnostic biomarkers for alcoholic pancreatitis was investigated. METHODS: A prospective blinded study compared FAEEs, NEFAs, and ethanol blood levels on hospitalization for alcoholic pancreatitis (n = 31), alcohol intoxication (n = 25), and in normal controls (n = 43). Serum FAEEs were measured at admission for nonalcoholic pancreatitis (n = 75). Mechanistic cell and animal studies were done. RESULTS: Median FAEEs were similarly elevated during alcohol intoxication (205 nmol/L; 95% confidence interval [CI], 71.8-515 nmol/L, P < .001) and alcoholic pancreatitis (103.1 nmol/L; 95% CI, 53-689 nmol/L, P < .001) vs controls (1.7 nmol/L; 95% CI, 0.02-4.3 nmol/L) or nonalcoholic pancreatitis (8 nmol/L; 95% CI, 1.1-11.5 nmol/L). Alcoholic pancreatitis increased serum NEFAs (1024 ± 710 µmol/L vs 307 ± 185 µmol/L in controls, P < .05). FAEEs comprised 0.1% to 2% of the parent NEFA concentrations. FAEES correlated strongly with NEFAs independent of ethanol levels in alcoholic pancreatitis but not during alcohol intoxication. On receiver operating characteristic curve analysis for diagnosing alcoholic pancreatitis, the area under the curve for serum FAEEs was 0.87 (95% CI, 0.78-0.95, P < .001). In mice and cells, alcohol administration transiently increased all FAEEs. Oleic acid ethyl ester was the only FAEE with a sustained increase up to 24 hours after intraperitoneal oleic acid plus ethanol administration. CONCLUSIONS: The sustained, alcohol-independent, large (20- to 50-fold) increase in circulating FAEEs during alcoholic pancreatitis results from their visceral release and mirrors the 2- to 4-fold increase in parent NEFA. The large areas under the curve of FAEEs on receiver operating characteristic curve analysis supports their role as alcoholic pancreatitis biomarkers.

Effects of Increased Central Cholinergic Activity on the Metabolic Challenge Induced by Submaximal Exercise in Rats: Adrenomedullary Secretion Influences.

AIM: The aim of this study was to assess the influence of adrenomedullary secretion on the plasma glucose, lactate, and free fatty acids (FFAs) during running exercise in rats submitted to intracerebroventricular (i.c.v.) injection of physostigmine (PHY). PHY i.c.v. was used to activate the central cholinergic system. METHODS: Wistar rats were divided into sham-saline (sham-SAL), sham-PHY, adrenal medullectomy-SAL, and ADM-PHY groups. The plasma concentrations of glucose, lactate, and FFAs were determined immediately before and after i.c.v. injection of 20 µL of SAL or PHY at rest and during running exercise on a treadmill. RESULTS: The i.c.v. injection of PHY at rest increased plasma glucose in the sham group, but not in the ADM group. An increase in plasma glucose, lactate, and FFAs mobilization from adipose tissue was observed during physical exercise in the sham-SAL group; however, the increase in plasma glucose was greater with i.c.v. PHY. Moreover, the hyperglycemia induced by exercise and PHY in the ADM group were blunted by ADM, whereas FFA mobilization was unaffected. CONCLUSION: These results indicate that there is a dual metabolic control by which activation of the central cholinergic pathway increases plasma glucose but not FFA during rest and exercise, and that this hyperglycemic response is dependent on adrenomedullary secretion.

Adipocyte-specific deletion of Tcf7l2 induces dysregulated lipid metabolism and impairs glucose tolerance in mice.

AIMS/HYPOTHESIS: Transcription factor 7-like 2 (TCF7L2) is a downstream effector of the Wnt/ß-catenin signalling pathway implicated in type 2 diabetes risk through genome-wide association studies. Although its expression is critical for adipocyte development, the potential roles of changes in adipose tissue TCF7L2 levels in diabetes risk are poorly defined. Here, we investigated whether forced changes in Tcf7l2 expression in adipocytes affect whole body glucose or lipid metabolism and crosstalk between disease-relevant tissues. METHODS: Tcf7l2 was selectively ablated in mature adipocytes in C57BL/6J mice using Cre recombinase under Adipoq promoter control to recombine Tcf7l2 alleles floxed at exon 1 (referred to as aTCF7L2 mice). aTCF7L2 mice were fed normal chow or a high-fat diet for 12 weeks. Glucose and insulin sensitivity, as well as beta cell function, were assessed in vivo and in vitro. Levels of circulating NEFA, selected hormones and adipokines were measured using standard assays. RESULTS: Reduced TCF7L2 expression in adipocytes altered glucose tolerance and insulin secretion in male but not in female mice. Thus, on a normal chow diet, male heterozygote knockout mice (aTCF7L2het) exhibited impaired glucose tolerance at 16 weeks (p = 0.03) and increased fat mass (1.4 ± 0.1-fold, p = 0.007) but no changes in insulin secretion. In contrast, male homozygote knockout (aTCF7L2hom) mice displayed normal body weight but impaired oral glucose tolerance at 16 weeks (p = 0.0001). These changes were mechanistically associated with impaired in vitro glucose-stimulated insulin secretion (decreased 0.5 ± 0.1-fold vs control mice, p = 0.02) and decreased levels of the incretins glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide (0.6 ± 0.1-fold and 0.4 ± 0.1-fold vs control mice, p = 0.04 and p < 0.0001, respectively). Circulating levels of plasma NEFA and fatty acid binding protein 4 were increased by 1.3 ± 0.1-fold and 1.8 ± 0.3-fold vs control mice (p = 0.03 and p = 0.05, respectively). Following exposure to a high-fat diet for 12 weeks, male aTCF7L2hom mice exhibited reduced in vivo glucose-stimulated insulin secretion (0.5 ± 0.1-fold vs control mice, p = 0.02). CONCLUSIONS/INTERPRETATION: Loss of Tcf7l2 gene expression selectively in adipocytes leads to a sexually dimorphic phenotype, with impairments not only in adipocytes, but also in pancreatic islet and enteroendocrine cells in male mice only. Our findings suggest novel roles for adipokines and incretins in the effects of diabetes-associated variants in TCF7L2, and further illuminate the roles of TCF7L2 in glucose homeostasis and diabetes risk. Graphical abstract.

Association of cardiac autonomic dysfunction with higher levels of plasma lipid metabolites in recent-onset type 2 diabetes.

AIMS/HYPOTHESIS: Emerging evidence suggests that in addition to hyperglycaemia, dyslipidaemia could represent a contributing pathogenetic factor to diabetic neuropathy, while obesity and insulin resistance play a role in the development of diabetic cardiac autonomic neuropathy (CAN) characterised by reduced heart rate variability (HRV), particularly in type 2 diabetes. We hypothesised that distinct lipid metabolites are associated with diminished HRV in recent-onset type 2 diabetes rather than type 1 diabetes. METHODS: We analysed 127 plasma lipid metabolites (11 acylcarnitines, 39 NEFA, 12 sphingomyelins (SMs), 56 phosphatidylcholines and nine lysophosphatidylcholines) using MS in participants from the German Diabetes Study baseline cohort recently diagnosed with type 1 (n = 100) and type 2 diabetes (n = 206). Four time-domain HRV indices (number of normal-to-normal (NN) intervals >50 ms divided by the number of all NN intervals [pNN50]; root mean square of successive differences [RMSSD]; SD of NN intervals [SDNN]; and SD of differences between adjacent NN intervals) and three frequency-domain HRV indices (very-low-frequency [VLF], low-frequency [LF] and high-frequency [HF] power spectrum) were computed from NN intervals recorded during a 3 h hyperinsulinaemic-euglycaemic clamp at baseline and in subsets of participants with type 1 (n = 60) and type 2 diabetes (n = 95) after 5 years. RESULTS: In participants with type 2 diabetes, after Bonferroni correction and rigorous adjustment, SDNN was inversely associated with higher levels of diacyl-phosphatidylcholine (PCaa) C32:0, PCaa C34:1, acyl-alkyl-phosphatidylcholine (PCae) C36:0, SM C16:0 and SM C16:1. SD of differences between NN intervals was inversely associated with PCaa C32:0, PCaa C34:1, PCaa C34:2, PCae C36:0 and SM C16:1, and RMSSD with PCae C36:0. For VLF power, inverse associations were found with PCaa C30:0, PCaa C32:0, PCaa C32:1, PCaa C34:2 and SM C16:1, and for LF power inverse associations were found with PCaa C32:0 and SM C16:1 (r = -0.242 to r = -0.349; p ≤ 0.0005 for all correlations). In contrast, no associations of lipid metabolites with measures of cardiac autonomic function were noted in participants recently diagnosed with type 1 diabetes. After 5 years, HRV declined due to ageing rather than diabetes, whereby prediction analyses for lipid metabolites were hampered. CONCLUSIONS/INTERPRETATION: Higher plasma levels of specific lipid metabolites are closely linked to cardiac autonomic dysfunction in recent-onset type 2 diabetes but not type 1 diabetes, suggesting a role for perturbed lipid metabolism in the early development of CAN in type 2 diabetes. Graphical abstract.

Postexercise changes in myocellular lipid droplet characteristics of young lean individuals are affected by circulatory nonesterified fatty acids.

Intramyocellular lipid (IMCL) content is an energy source during acute exercise. Nonesterified fatty acid (NEFA) levels can compete with IMCL utilization during exercise. IMCL content is stored as lipid droplets (LDs) that vary in size, number, subcellular distribution, and in coating with LD protein PLIN5. Little is known about how these factors are affected during exercise and recovery. Here, we aimed to investigate the effects of acute exercise with and without elevated NEFA levels on intramyocellular LD size and number, intracellular distribution and PLIN5 coating, using high-resolution confocal microscopy. In a crossover study, 9 healthy lean young men performed a 2-h moderate intensity cycling protocol in the fasted (high NEFA levels) and glucose-fed state (low NEFA levels). IMCL and LD parameters were measured at baseline, directly after exercise and 4 h postexercise. We found that total IMCL content was not changed directly after exercise (irrespectively of condition), but IMCL increased 4 h postexercise in the fasting condition, which was due to an increased number of LDs rather than changes in size. The effects were predominantly detected in type I muscle fibers and in LDs coated with PLIN5. Interestingly, subsarcolemmal, but not intermyofibrillar IMCL content, was decreased directly after exercise in the fasting condition and was replenished during the 4 h recovery period. In conclusion, acute exercise affects IMCL storage during exercise and recovery, particularly in type I muscle fibers, in the subsarcolemmal region and in the presence of PLIN5. Moreover, the effects of exercise on IMCL content are affected by plasma NEFA levels.NEW & NOTEWORTHY Skeletal muscle stores lipids in lipid droplets (LDs) that can vary in size, number, and location and are a source of energy during exercise. Specifically, subsarcolemmal LDs were used during exercise when fasted. Exercising in the fasted state leads to postrecovery elevation in IMCL levels due to an increase in LD number in type I muscle fibers, in subsarcolemmal region and decorated with PLIN5. These effects are blunted by glucose ingestion during exercise and recovery.

Agonist of RORA Attenuates Nonalcoholic Fatty Liver Progression in Mice via Up-regulation of MicroRNA 122.

BACKGROUND & AIMS: Development of nonalcoholic steatohepatitis (NASH) is associated with reductions in hepatic microRNA122 (MIR122); the RAR related orphan receptor A (RORA) promotes expression of MIR122. Increasing expression of RORA in livers of mice increases expression of MIR122 and reduces lipotoxicity. We investigated the effects of a RORA agonist in mouse models of NASH. METHODS: We screened a chemical library to identify agonists of RORA and tested their effects on a human hepatocellular carcinoma cell line (Huh7). C57BL/6 mice were fed a chow or high-fat diet (HFD) for 4 weeks to induce fatty liver. Mice were given hydrodynamic tail vein injections of a MIR122 antagonist (antagomiR-122) or a control antagomiR once each week for 3 weeks while still on the HFD or chow diet, or intraperitoneal injections of the RORA agonist RS-2982 or vehicle, twice each week for 3 weeks. Livers, gonad white adipose, and skeletal muscle were collected and analyzed by reverse-transcription polymerase chain reaction, histology, and immunohistochemistry. A separate group of mice were fed an atherogenic diet, with or without injections of RS-2982 for 3 weeks; livers were analyzed by immunohistochemistry, and plasma was analyzed for levels of aminotransferases. We analyzed data from liver tissues from patients with NASH included in the RNA-sequencing databases GSE33814 and GSE89632. RESULTS: Injection of mice with antagomiR-122 significantly reduced levels of MIR122 in plasma, liver, and white adipose tissue; in mice on an HFD, antagomiR-122 injections increased fat droplets and total triglyceride content in liver and reduced ß-oxidation and energy expenditure, resulting in significantly more weight gain than in mice given the control microRNA. We identified RS-2982 as an agonist of RORA and found it to increase expression of MIR122 promoter activity in Huh7 cells. In mice fed an HFD or atherogenic diet, injections of RS-2982 increased hepatic levels of MIR122 precursors and reduced hepatic synthesis of triglycerides by reducing expression of biosynthesis enzymes. In these mice, RS-2982 significantly reduced hepatic lipotoxicity, reduced liver fibrosis, increased insulin resistance, and reduced body weight compared with mice injected with vehicle. Patients who underwent cardiovascular surgery had increased levels of plasma MIR122 compared to its levels before surgery; increased expression of plasma MIR122 was associated with increased levels of plasma free fatty acids and levels of RORA. CONCLUSIONS: We identified the compound RS-2982 as an agonist of RORA that increases expression of MIR122 in cell lines and livers of mice. Mice fed an HFD or atherogenic diet given injections of RS-2982 had reduced hepatic lipotoxicity, liver fibrosis, and body weight compared with mice given the vehicle. Agonists of RORA might be developed for treatment of NASH.

Nonesterified Fatty Acids and Kidney Function Decline in Older Adults: Findings From the Cardiovascular Health Study.

RATIONALE & OBJECTIVE: Circulating nonesterified fatty acids (NEFAs) make up a small portion of circulating lipids but are a metabolically important energy source. Excessive circulating NEFAs may contribute to lipotoxicity in many tissues, including the kidneys. We investigated the relationship between total circulating NEFA concentration and kidney outcomes in older, community-dwelling adults. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 4,698 participants≥65 years of age in the Cardiovascular Health Study who underwent total fasting serum NEFA concentration measurements in 1992-1993. EXPOSURE: Fasting serum NEFA concentration at one time point. OUTCOME: Three primary outcomes: estimated glomerular filtration rate (eGFR) decline of≥30%, the composite of eGFR decline≥30% or kidney failure with replacement therapy, and change in eGFR. These outcomes were assessed over 4- and 13-year periods. ANALYTICAL APPROACH: Logistic regression for the dichotomous outcomes and mixed effects models for the continuous outcome, with sequential adjustment for baseline covariates. Inverse probability of attrition weighting was implemented to account for informative attrition during the follow-up periods. RESULTS: Serum NEFA concentrations were not independently associated with kidney outcomes. In unadjusted and partially adjusted analyses, the highest quartile of serum NEFA concentration (compared with lowest) was associated with a higher risk of≥30% eGFR decline at 4 years and faster rate of decline of eGFR. No associations were evident after adjustment for comorbidities, lipid levels, insulin sensitivity, medications, and vital signs: the odds ratio for the eGFR decline outcome was 1.33 (95% CI, 0.83-2.13), and the difference in eGFR slope in the highest versus lowest quartile of serum NEFA concentration was-0.15 (95% CI, -0.36 to 0.06) mL/min/1.73m2 per year. LIMITATIONS: Single NEFA measurements, no measurements of post-glucose load NEFA concentrations or individual NEFA species, no measurement of baseline urine albumin. CONCLUSIONS: A single fasting serum NEFA concentration was not independently associated with long-term adverse kidney outcomes in a cohort of older community-living adults.

Prognostic significance of pretreatment serum free fatty acid in patients with diffuse large B-cell lymphoma in the rituximab era: a retrospective analysis.

BACKGROUND: Fatty acid metabolism is reportedly associated with various cancers. However, the role of pretreatment serum free fatty acid (FFA) levels in diffuse large B-cell lymphoma (DLBCL) prognosis is still unclear, and our study aimed to better elucidate its influence on clinical outcomes. METHODS: The medical records of 221 newly diagnosed DLBCL patients admitted to Fujian Medical University Union Hospital from January 2011 to December 2016 were analysed retrospectively. Receiver operating characteristic curve analysis was used to determine a cut-off value for pretreatment serum FFA levels for prognostic prediction in DLBCL patients. The relationship between pretreatment serum FFA levels and clinical and laboratory parameters was analysed. Univariate and multivariate analyses were used to assess prognostic factors for overall survival (OS) and progression-free survival (PFS). RESULTS: Newly diagnosed DLBCL patients with high pretreatment serum FFA levels (≥0.495 mmol/l) had more B symptoms, higher serum lactate dehydrogenase levels (> upper limit of normal), >1 extranodal site, and higher International Prognostic Index score (3-5) compared to those with low pretreatment serum FFA levels (<0.495 mmol/l). Higher serum FFA levels were independent prognostic factors for poor OS, but not PFS. CONCLUSIONS: High pretreatment serum FFA levels are associated with lower survival in untreated DLBCL patients.

Beneficial effect on serum cholesterol levels, but not glycaemic regulation, after replacing SFA with PUFA for 3 d: a randomised crossover trial.

Replacing intake of SFA with PUFA reduces serum cholesterol levels and CVD risk. The effect on glycaemic regulation is, however, less clear. The main objective of the present study was to investigate the short-term effect of replacing dietary SFA with PUFA on glycaemic regulation. Seventeen healthy, normal-weight participants completed a 25-d double-blind, randomised and controlled two-period crossover study. Participants were allocated to either interventions with PUFA products or SFA products (control) in a random order for three consecutive days, separated by a 1·5-week washout period between the intervention periods. Glucose, insulin and TAG were measured before and after an oral glucose tolerance test. In addition, fasting total cholesterol, NEFA and plasma total fatty acid profile were measured before and after the 3-d interventions. Fasting and postprandial glucose, insulin, and TAG levels and fasting levels of NEFA and plasma fatty acid profile did not differ between the groups. However, replacing dietary SFA with PUFA significantly reduced total cholesterol levels by 8 % after 3 d (P = 0·002). Replacing dietary SFA with PUFA for only 3 d has beneficial cardio-metabolic effects by reducing cholesterol levels in healthy individuals.