Effects of Ambient Air Pollution on Brain Cortical Thickness and Subcortical Volume: A Longitudinal Neuroimaging Study.

INTRODUCTION: Several cross-sectional studies have shown that long-term exposures to air pollutants are associated with smaller brain cortical volume or thickness. Here, we investigated longitudinal associations of long-term air pollution exposures with cortical thickness and subcortical volume. METHODS: In this longitudinal study, we included a prospective cohort of 361 adults residing in four cities in the Republic of Korea. Long-term concentrations of particulate matter with aerodynamic diameters of ≤10 µm (PM10) and ≤2.5 µm (PM2.5) and nitrogen dioxide (NO2) at residential addresses were estimated. Neuroimaging markers (cortical thickness and subcortical volume) were obtained from brain magnetic resonance images at baseline (August 2014 to March 2017) and at the 3-year follow-up (until September 2020). Linear mixed-effects models were used, adjusting for covariates. RESULTS: A 10-µg/m3 increase in PM10 was associated with reduced whole-brain mean (ß = -0.45, standard error [SE] = 0.10; p < 0.001), frontal (ß = -0.53, SE = 0.11; p < 0.001) and temporal thicknesses (ß = -0.37, SE = 0.12; p = 0.002). A 10-ppb increase in NO2 was associated with a decline in the whole-brain mean cortical thickness (ß = -0.23, SE = 0.05; p < 0.001), frontal (ß = -0.25, SE = 0.05; p < 0.001), parietal (ß = -0.12, SE = 0.05; p = 0.025), and temporal thicknesses (ß = -0.19, SE = 0.06; p = 0.001). Subcortical structures associated with air pollutants included the thalamus. CONCLUSIONS: Long-term exposures to PM10 and NO2 may lead to cortical thinning in adults.

Metabolic traits affecting the relationship between liver fat and intrapancreatic fat: a mediation analysis.

AIMS/HYPOTHESIS: The clinical importance of fat deposition in the liver and pancreas is increasingly recognised. However, to what extent deposition of fat in these two depots is affected by intermediate variables is unknown. The aim of this work was to conduct a mediation analysis with a view to uncovering the metabolic traits that underlie the relationship between liver fat and intrapancreatic fat deposition (IPFD) and quantifying their effect. METHODS: All participants underwent MRI/magnetic resonance spectroscopy on the same 3.0 T scanner to determine liver fat and IPFD. IPFD of all participants was quantified manually by two independent raters in duplicate. A total of 16 metabolic traits (representing markers of glucose metabolism, incretins, lipid panel, liver enzymes, pancreatic hormones and their derivatives) were measured in blood. Mediation analysis was conducted, taking into account age, sex, ethnicity and BMI. Significance of mediation was tested by computing bias-corrected bootstrap CIs with 5000 repetitions. RESULTS: A total of 353 individuals were studied. Plasma glucose, HDL-cholesterol and triacylglycerol mediated 6.8%, 17.9% and 24.3%, respectively, of the association between liver fat and IPFD. Total cholesterol, LDL-cholesterol, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transpeptidase, insulin, glucagon, amylin, C-peptide, HbA1c, glucagon-like peptide-1 and gastric inhibitory peptide did not mediate the association between liver fat and IPFD. CONCLUSIONS/INTERPRETATION: At least one-quarter of the association between liver fat and IPFD is mediated by specific blood biomarkers (triacylglycerol, HDL-cholesterol and glucose), after accounting for potential confounding by age, sex, ethnicity and BMI. This unveils the complexity of the association between the two fat depots and presents specific targets for intervention.

Remnant cholesterol, but not low-density lipoprotein cholesterol, is associated with intra-pancreatic fat deposition.

AIM: To investigate the associations of components of the lipid panel (and its derivatives) with intra-pancreatic fat deposition (IPFD). METHODS: All participants underwent abdominal magnetic resonance imaging on the same 3.0-Tesla scanner and IPFD was quantified. Blood samples were collected in the fasted state for analysis of lipid panel components. A series of linear regression analyses was conducted, adjusting for age, sex, ethnicity, body mass index, fasting plasma glucose, homeostatic model assessment of insulin resistance, and liver fat deposition. RESULTS: A total of 348 participants were included. Remnant cholesterol (P = 0.010) and triglyceride levels (P = 0.008) were positively, and high-density lipoprotein cholesterol level (P = 0.001) was negatively, associated with total IPFD in the most adjusted model. Low-density lipoprotein cholesterol and total cholesterol were not significantly associated with total IPFD. Of the lipid panel components investigated, remnant cholesterol explained the greatest proportion (9.9%) of the variance in total IPFD. CONCLUSION: Components of the lipid panel have different associations with IPFD. This may open up new opportunities for improving outcomes in people at high risk for cardiovascular diseases (who have normal low-density lipoprotein cholesterol) by reducing IPFD.

Negative self-regulation of transient receptor potential canonical 4 by the specific interaction with phospholipase C-δ1.

Transient receptor potential canonical (TRPC) channels are non-selective calcium-permeable cation channels. It is suggested that TRPC4ß is regulated by phospholipase C (PLC) signaling and is especially maintained by phosphatidylinositol 4,5-bisphosphate (PIP2). In this study, we present the regulation mechanism of the TRPC4 channel with PIP2 hydrolysis which is mediated by a channel-bound PLCδ1 but not by the GqPCR signaling pathway. Our electrophysiological recordings demonstrate that the Ca2+ via an open TRPC4 channel activates PLCδ1 in the physiological range, and it causes the decrease of current amplitude. The existence of PLCδ1 accelerated PIP2 depletion when the channel was activated by an agonist. Interestingly, PLCδ1 mutants which have lost the ability to regulate PIP2 level failed to reduce the TRPC4 current amplitude. Our results demonstrate that TRPC4 self-regulates its activity by allowing Ca2+ ions into the cell and promoting the PIP2 hydrolyzing activity of PLCδ1.

Intrapancreatic, Liver, and Skeletal Muscle Fat Depositions in First Attack of Acute Pancreatitis Versus Health.

INTRODUCTION: Increased intrapancreatic fat deposition (IPFD) has emerged as a harbinger of pancreatic cancer and chronic pancreatitis. Although it is well recognized that diseases of the exocrine pancreas often lie on a continuum (with acute pancreatitis preceding the development of chronic pancreatitis and/or pancreatic cancer), whether increased IPFD predisposes to acute pancreatitis is unknown. This study aimed to compare fat depositions in the pancreas (as well as the liver and skeletal muscle) between individuals who developed first attack of acute pancreatitis and healthy individuals. METHODS: This was a matched case-control study nested into population-based cohort. MRI on a single 3 T scanner was used to quantify intrapancreatic, liver, and skeletal muscle fat depositions using the same protocols in all study participants. Binary logistic regression with adjustment for body mass index and other possible confounders was performed. RESULTS: Fifty individuals with first attack of nonnecrotizing acute pancreatitis comprised the case group and 100 healthy individuals comprised the control group. A 1% increase in IPFD (but not the other fat depositions) was significantly associated with a more than 30% higher chance of developing first attack of acute pancreatitis, consistently in both the unadjusted ( P = 0.004) and all adjusted models. Furthermore, a 1% increase in IPFD (but not the other fat depositions) was significantly associated with up to a 27% higher chance of developing first attack of acute pancreatitis in individuals with normotriglyceridemia, consistently in both the unadjusted ( P = 0.030) and all adjusted models. DISCUSSION: Increased IPFD may predispose to the development of acute pancreatitis. This opens up opportunities for reducing the burden of acute pancreatitis by means of primary prevention.

Cytokine signature for predicting new-onset prediabetes after acute pancreatitis: A prospective longitudinal cohort study.

BACKGROUND/PURPOSE: Acute inflammation of the pancreas often leads to metabolic sequelae, the most common of which is new-onset prediabetes (and, ultimately, diabetes). However, there is a lack of studies on predictors of this sequela. The aim was to investigate whether cytokines/chemokines measured at baseline are predictive of new-onset prediabetes after acute pancreatitis (NOPAP). METHODS: This was a prospective longitudinal cohort study (as part of the LACERTA project) that included 68 individuals with non-necrotising acute pancreatitis who had no diabetes mellitus. Of them, 17 individuals had prediabetes at baseline and during follow-up, 37 individuals had normoglycaemia at baseline and during follow-up, and 14 individuals had normoglycaemia at baseline and developed NOPAP during follow-up. A commercially available human cytokine/chemokine multiplex kit was used to measure a total of 28 analytes at baseline. Multinomial regression analyses were conducted to investigate the associations between the cytokines/chemokines and the three study groups. RESULTS: Interleukin-1ß and interferon γ significantly predicted progression to NOPAP with an odds ratio (95% confidence interval) of 1.097 (1.002, 1.201) and 1.094 (1.003, 1.192), respectively (after accounting for age, sex, body mass index, and aetiology of acute pancreatitis). None of the studied cytokines/chemokines showed statistically significant associations with the antecedent prediabetes group (after accounting for the above covariates). CONCLUSION: Elevated levels of interleukin-1ß and interferon γ in acute pancreatitis individuals with normoglycaemia at baseline may predict progression to NOPAP during follow-up.

Higher expression of KCNK10 (TREK-2) K+ channels and their functional upregulation by lipopolysaccharide treatment in mouse peritoneal B1a cells.

Innate-like CD5+ B1a cells localized in serous cavities are activated by innate stimuli, such as lipopolysaccharide (LPS), leading to T cell-independent antibody responses. Although ion channels play crucial roles in the homeostasis and activation of immune cells, the electrophysiological properties of B1a cells have not been investigated to date. Previously, in the mouse B cell lymphoma cells, we found that the voltage-independent two-pore-domain potassium (K2P) channels generate a negative membrane potential and drive Ca2+ influx. Here, we newly compared the expression and activities of K2P channels in mouse splenic follicular B (FoB), marginal zone B (MZB), and peritoneal B1a cells. Next-generation sequencing analysis showed higher levels of transcripts for TREK-2 and TWIK-2 in B1a cells than those in FoB or MZB cells. Electrophysiological analysis, using patch clamp technique, revealed higher activity of TREK-2 with the characteristic large unitary conductance (~ 250 pS) in B1a than that in FoB or MZB cells. TREK-2 activity was further increased by LPS treatment (>2 h), which was more prominent in B1a than that in MZB or FoB cells. The cytosolic Ca2+ concentration of B cells was decreased by high-K+-induced depolarization (ΔRKCl (%)), suggesting the basal Ca2+ influx to be driven by negative membrane potential. The LPS treatment significantly increased the ΔRKCl (%) in B1a, though not in FoB and MZB cells. Our study was the first to compare the K2P channels in mouse primary B cell subsets, elucidating the functional upregulation of TREK-2 and augmentation of Ca2+ influx by the stimulation of Toll-like receptor 4 in B1a cells.

Acute Nutritional Ketosis and Its Implications for Plasma Glucose and Glucoregulatory Peptides in Adults with Prediabetes: A Crossover Placebo-Controlled Randomized Trial.

BACKGROUND: The potential of a ketone monoester (ß-hydroxybutyrate; KEßHB) supplement to rapidly mimic a state of nutritional ketosis offers a new therapeutic possibility for diabetes prevention and management. While KEßHB supplementation has a glucose-lowering effect in adults with obesity, its impact on glucose control in other insulin-resistant states is unknown. OBJECTIVES: The primary objective was to investigate the effect of KEßHB-supplemented drink on plasma glucose in adults with prediabetes. The secondary objective was to determine its impact on plasma glucoregulatory peptides. METHODS: This randomized controlled trial [called CETUS (Cross-over randomizEd Trial of ß-hydroxybUtyrate in prediabeteS)] included 18 adults [67% men, mean age = 55 y, mean BMI (kg/m2) = 28.4] with prediabetes (glycated hemoglobin between 5.7% and 6.4% and/or fasting plasma glucose between 100 and 125 mg/dL). Participants were randomly assigned to receive KEßHB-supplemented and placebo drinks in a crossover sequence (washout period of 7-10 d between the drinks). Blood samples were collected from 0 to 150 min, at intervals of 30 min. Paired-samples t tests were used to investigate the change in the outcome variables [ß-hydroxybutyrate (ßHB), glucose, and glucoregulatory peptides] after both drinks. Repeated measures analyses were conducted to determine the change in concentrations of the prespecified outcomes over time. RESULTS: Blood ßHB concentrations increased to 3.5 mmol/L within 30 minutes after KEßHB supplementation. Plasma glucose AUC was significantly lower after KEßHB supplementation than after the placebo [mean difference (95% CI): -59 (-85.3, -32.3) mmol/L × min]. Compared with the placebo, KEßHB supplementation led to significantly greater AUCs for plasma insulin [0.237 (0.044, 0.429) nmol/L × min], C-peptide [0.259 (0.114, 0.403) nmol/L × min], and glucose-dependent insulinotropic peptide [0.243 (0.085, 0.401) nmol/L × min], with no significant differences in the AUCs for amylin, glucagon, and glucagon-like peptide 1. CONCLUSIONS: Ingestion of the KEßHB-supplemented drink acutely increased the blood ßHB concentrations and lowered the plasma glucose concentrations in adults with prediabetes. Further research is needed to investigate the dynamics of repeated ingestions of a KEßHB supplement by individuals with prediabetes, with a view to preventing new-onset diabetes. This trial was registered at www.clinicaltrials.gov as NCT03889210.

Dietary carbohydrate intake and insulin traits in individuals after acute pancreatitis: Effect modification by intra-pancreatic fat deposition.

OBJECTIVES: Current knowledge of the link between dietary carbohydrate intake and insulin regulation in individuals after an attack of pancreatitis is limited. We aimed to investigate the associations between dietary carbohydrate intake and insulin traits in post-pancreatitis versus healthy individuals, taking into account intrapancreatic fat deposition (IPFD). METHODS: All participants underwent magnetic resonance imaging (using the same protocol and 3T scanner) to quantify IPFD. Dietary carbohydrate intake was assessed using a validated 131-item food frequency questionnaire. Insulin, HOMA-IR, HOMA-ß were determined in the fasted state. Linear regression and effect modification analyses were conducted in unadjusted and adjusted models (accounting for age, sex, body mass index, daily energy intake, use of anti-diabetic medications, and recurrence of acute pancreatitis). RESULTS: The study included 111 post-pancreatitis individuals (categorized into low IPFD (n = 33), moderate IPFD (n = 40), high IPFD (n = 38)) and 47 healthy controls. In the high IPFD group, starch intake was negatively associated with fasting insulin and HOMA-ß in both the unadjusted (p < 0.001 both) and fully adjusted models (p < 0.001 both); and with HOMA-IR in the fully adjusted model (p < 0.001) only. Total sugar intake was positively associated with fasting insulin (p = 0.015) and HOMA-ß (p = 0.007) in the fully adjusted model but not associated with HOMA-IR. None of the above associations was statistically significant in the low IPFD, moderate IPFD, and healthy controls groups. The studied associations were more pronounced in the high IPFD group but not in the moderate IPFD or low IPFD groups (when compared with the healthy controls group). CONCLUSIONS: Dietary carbohydrate intake is differentially associated with insulin traits in individuals after an attack of pancreatitis and the associations are modified by IPFD. These findings will be helpful for the development of dietary guidelines specifically for individuals after an attack of pancreatitis.

Relationship of pancreas volume to tobacco smoking and alcohol consumption following pancreatitis.

BACKGROUND: Tobacco smoking and alcohol consumption are established risk factors for diseases of the pancreas. With the recent advances in imaging modalities (such as magnetic resonance (MR) imaging), opportunities have arisen to study pancreas size, in both health and disease. Studies investigating the relationship between tobacco smoking, alcohol consumption, and total pancreas volume (TPV) - a holistic measure of pancreatic exocrine reserve - are lacking. The aim of the present study was to investigate the associations between MR-derived TPV and tobacco smoking/alcohol consumption. METHODS: This cross-sectional study recruited individuals with a history of pancreatitis and healthy controls. A validated questionnaire was used to ascertain current and lifetime tobacco smoking and alcohol consumption. TPV was quantified using MR images by two independent raters. Generalized additive models and linear regression analyses were conducted and adjusted for demographic, metabolic, and pancreatitis-related factors. RESULTS: A total of 107 individuals following pancreatitis and 38 healthy controls were included. There was no statistically significant difference in TPV between any of the tobacco smoking/alcohol consumption categories of individuals following pancreatitis and healthy controls, in both unadjusted and adjusted analyses. In individuals following pancreatitis, multivariate linear regression found no association between TPV and 7 smoking- and alcohol-related variables. Sensitivity analyses constrained to individuals who did not abstain from either smoking or drinking following their first attack of pancreatitis did not yield statistical significance with TPV. In post-hoc analysis, age was significantly inversely associated with TPV in the most adjusted model (p = 0.016). CONCLUSIONS: This is the first study to investigate the association between tobacco smoking, alcohol consumption, and MR-derived TPV following pancreatitis. It appears that age, but not tobacco smoking or alcohol consumption, is associated with a significantly reduced TPV.