Ketogenic Diets Alter the Gut Microbiome Resulting in Decreased Intestinal Th17 Cells.

Very low-carbohydrate, high-fat ketogenic diets (KDs) induce a pronounced shift in metabolic fuel utilization that elevates circulating ketone bodies; however, the consequences of these compounds for host-microbiome interactions remain unknown. Here, we show that KDs alter the human and mouse gut microbiota in a manner distinct from high-fat diets (HFDs). Metagenomic and metabolomic analyses of stool samples from an 8-week inpatient study revealed marked shifts in gut microbial community structure and function during the KD. Gradient diet experiments in mice confirmed the unique impact of KDs relative to HFDs with a reproducible depletion of bifidobacteria. In vitro and in vivo experiments showed that ketone bodies selectively inhibited bifidobacterial growth. Finally, mono-colonizations and human microbiome transplantations into germ-free mice revealed that the KD-associated gut microbiota reduces the levels of intestinal pro-inflammatory Th17 cells. Together, these results highlight the importance of trans-kingdom chemical dialogs for mediating the host response to dietary interventions.

Brown remodeling of white adipose tissue by SirT1-dependent deacetylation of Pparγ.

Brown adipose tissue (BAT) can disperse stored energy as heat. Promoting BAT-like features in white adipose (WAT) is an attractive, if elusive, therapeutic approach to staunch the current obesity epidemic. Here we report that gain of function of the NAD-dependent deacetylase SirT1 or loss of function of its endogenous inhibitor Deleted in breast cancer-1 (Dbc1) promote "browning" of WAT by deacetylating peroxisome proliferator-activated receptor (Ppar)-γ on Lys268 and Lys293. SirT1-dependent deacetylation of Lys268 and Lys293 is required to recruit the BAT program coactivator Prdm16 to Pparγ, leading to selective induction of BAT genes and repression of visceral WAT genes associated with insulin resistance. An acetylation-defective Pparγ mutant induces a brown phenotype in white adipocytes, whereas an acetylated mimetic fails to induce "brown" genes but retains the ability to activate "white" genes. We propose that SirT1-dependent Pparγ deacetylation is a form of selective Pparγ modulation of potential therapeutic import.

Higher Glycemic Index and Glycemic Load Diet Is Associated with Slower Disease Progression in Amyotrophic Lateral Sclerosis.

OBJECTIVE: High-caloric diets may slow the progression of amyotrophic lateral sclerosis; however, key macronutrients have not been identified. We examined whether dietary macronutrients are associated with the rate of progression and length of survival among the prospective cohort study participants. METHODS: Participants with a confirmed diagnosis of sporadic amyotrophic lateral sclerosis enrolled in the Multicenter Cohort Study of Oxidative Stress were included (n = 304). We evaluated baseline macronutrient intake assessed by food frequency questionnaire in relation to change in revised amyotrophic lateral sclerosis functional rating scale total-score, and tracheostomy-free survival using linear regression and Cox proportional hazard models. Baseline age, sex, disease duration, diagnostic certainty, body mass index, bulbar onset, revised amyotrophic lateral sclerosis functional rating scale total-score, and forced vital capacity were included as covariates. RESULTS: Baseline higher glycemic index and load were associated with less decline of revised amyotrophic lateral sclerosis functional rating scale total score at 3-month follow-up (ß = -0.13, 95% CI -0.2, -0.01, p = 0.03) and (ß = -0.01, 95% CI -0.03, -0.0007, p = 0.04), respectively. Glycemic index second-quartile, third-quartile, and fourth-quartile groups were associated with less decline at 3 months by 1.9 (95% CI -3.3, -0.5, p = 0.008), 2.0 (95% CI -3.3, -0.6, p = 0.006), and 1.6 (95% CI -3.0, -0.2, p = 0.03) points compared with the first-quartile group; the glycemic load fourth-quartile group had 1.4 points less decline compared with the first-quartile group (95% CI -2.8, 0.1, p = 0.07). Higher glycemic index was associated with a trend toward longer tracheostomy-free survival (HR 0.97, 95% CI 0.93, 1.00, p = 0.07). INTERPRETATION: Higher dietary glycemic index and load are associated with slower disease progression in amyotrophic lateral sclerosis. ANN NEUROL 2024;95:217-229.

Physiological, body composition, and body mass measures show that a developmental measure of weight suppression is more valid than the traditional measure.

OBJECTIVE: The traditional measure of weight suppression (TWS; the difference between an individual's highest past weight at adult height and current weight), has been associated with many psychological, behavioral and biological variables in those with eating disorders. A new measure of weight suppression, called developmental weight suppression (DWS), corrects two major problems in the original measure. Initial research indicates that DWS represents a superior operationalization of the construct weight suppression was originally designed to measure (Lowe [1993, Psychol Bull, 114: 100]). This study is the first to examine the relation between both WS measures and weight history, body composition and a variety of metabolic hormones. METHODS: Data were collected in 91 women with bulimia nervosa (BN) or BN-spectrum disorders. RESULTS: Both weight suppression indices were related to multiple hormones. However, multiple regression analyses showed that the independent effects of DWS differed from the independent effects of TWS in that only DWS was negatively related to: (1) current z-BMI, (2) body fat percentage, and (3) insulin, leptin, T3 free, and TSH. This differential pattern also occurred when results were corrected for multiple comparisons. DISCUSSION: Findings provide stronger biological support for the construct validity of DWS than TWS and suggest that: (1) from the perspective of individuals with BN, high DWS embodies success at food restriction and weight loss, (2) elevated DWS may trap individuals with BN in a powerful biobehavioral bind, and (3) DWS is the preferred measure of weight suppression in future research on eating disorders. PUBLIC SIGNIFICANCE: Most individuals with bulimia nervosa lose substantial weight in the process of developing their disorder. Such weight suppression is related to many characteristics of those with the eating disorder bulimia nervosa. This study shows why a new measure of weight suppression, based on an individual's growth during development, is more biologically valid than the traditional measure of weight suppression.

Weight History Correlates of Resting Energy Expenditure in Women With Bulimia Nervosa.

OBJECTIVE: Among those with bulimia nervosa, weight suppression has been associated with illness severity and treatment prognosis. Although significant weight loss is known to reduce metabolic rate, the relation between weight suppression and resting energy expenditure (REE) in bulimia nervosa has not been examined. This study tested the hypothesis of an inverse relation between weight suppression and REE in a sample of women with bulimia nervosa (N = 84). METHODS: In primary analyses, linear regressions were conducted between weight suppression and REE, corrected for fat-free mass. In follow-up, exploratory analyses, stepwise linear regressions were conducted to explore the main and interaction effects of weight history and weight suppression on REE. RESULTS: Neither traditional (TWS) nor developmental weight suppression (DWS) correlated with REE. Results from exploratory analyses, however, revealed a medium-to-large inverse relation between several weight history variables and REE (highest past weight, sr2 = 0.05; lowest postmorbid weight, sr2 = 0.07; current weight, sr2 = 0.05). Additionally, DWS interacted with current (sr2 = 0.08) and highest premorbid (sr2 = 0.05) z-BMI to influence REE with a medium-to-large effect. For individuals low in current and premorbid z-BMIs, higher DWS associated with lower REE levels. However, for individuals at higher premorbid z-BMIs, higher DWS unexpectedly associated with greater REE levels. DISCUSSION: In this sample of women with bulimia nervosa, reduced REE associated with higher weights across all timepoints. If the interaction effect between DWS and z-BMI history persists in future studies, this may indicate unique challenges faced by individuals low in z-BMI and high in DWS related to weight gain and normalization of eating.

Clinical attachment loss is cross-sectionally associated with elevated glucose among adults without diabetes.

AIM: We investigated whether periodontal measures are cross-sectionally associated with prediabetes and cardiometabolic biomarkers among non-diabetic younger adults. MATERIALS AND METHODS: One thousand seventy-one participants (mean age = 32.2 years [SE = 0.3]; 73% female) from the Oral Infections, Glucose Intolerance and Insulin Resistance Study were enrolled. Full-mouth clinical attachment loss (fm-CAL), probing depth (fm-PD) and bleeding on probing were ascertained. Interproximal CAL (i-CAL) and probing depths (i-PD) served as our primary exposures. Glucose, HbA1c, insulin and insulin resistance (HOMA-IR) outcomes were assessed from fasting blood. Prediabetes was defined per American Diabetes Association guidelines. Prediabetes prevalence ratios (PR [95% CI]) and mean [SE] cardiometabolic biomarkers were regressed on periodontal variables via multivariable robust variance Poisson regression or multivariable linear regression. RESULTS: Prevalence of prediabetes was 12.5%. Fully adjusted prediabetes PR in Tertiles 3 versus 1 of mean i-CAL was 2.42 (1.77, 3.08). Fully adjusted fasting glucose estimates across i-CAL tertiles were 83.29 [0.43], 84.31 [0.37], 86.48 [0.46]; p for trend <.01. Greater percent of sites with i-PD ≥3 mm showed elevated natural-log-HOMA-IR after adjustment (0%-12% of sites = 0.33 [0.03], 13%-26% of sites = 0.39 [0.03], ≥27% of sites = 0.42 [0.03]; p for trend = .04). CONCLUSIONS: i-CAL (vs. fm-CAL) was associated with elevated fasting glucose and prediabetes, whereas i-PD (vs. fm-PD) was associated with insulin resistance. Future studies are needed to examine periodontal disease and incident prediabetes.

p38 MAPK activation and STIM1-Orai3 association mediate TRPC6 externalization.

Endothelial cell (EC) migration is critical for the repair of monolayer disruption following angioplasties, but migration is inhibited by lipid oxidation products, including lysophosphatidylcholine (lysoPC), which open canonical transient receptor potential 6 (TRPC6) channels. TRPC6 activation requires an increase in intracellular Ca2+ concentration ([Ca2+]i), the source of which is unknown. LysoPC can activate phospholipase A2 to release arachidonic acid (ArA). ArA can activate arachidonic acid-regulated calcium (ARC) channels that are formed by stromal interaction molecule 1 (STIM1) and Orai1 and Orai3 proteins. Both lysoPC and ArA can activate p38 mitogen-activated protein kinase (MAPK) that induces the phosphorylation required for STIM1-Orai3 association. This is accompanied by an increase in [Ca2+]i and TRPC6 externalization. The effect of lysoPC and ArA is not additive, suggesting activation of the same pathway. The increase in [Ca2+]i activates an Src kinase that leads to TRPC6 activation. Downregulation of Orai3 using siRNA blocks the lysoPC- or ArA-induced increase in [Ca2+]i and TRPC6 externalization and preserves EC migration. These data show that lysoPC induces activation of p38 MAPK, which leads to STIM1-Orai3 association and increased [Ca2+]i. This increase in [Ca2+]i activates an Src kinase leading to TRPC6 externalization, which initiates a cascade of events ending in cytoskeletal changes that disrupt EC migration. Blocking this pathway preserves EC migration in the presence of lipid oxidation products.NEW & NOTEWORTHY The major lysophospholipid component in oxidized LDL, lysophosphatidylcholine (lysoPC), can activate p38 MAP kinase, which in turn promotes externalization of Orai3 and STIM1-Orai3 association, suggesting involvement of arachidonic acid-regulated calcium (ARC) channels. The subsequent increase in intracellular calcium activates an Src kinase required for TRPC6 externalization. TRPC6 activation, which has been shown to inhibit endothelial cell migration, is blocked by p38 MAP kinase or Orai3 downregulation, and this partially preserves endothelial migration in lysoPC.

Do referrals improve the representation of women in mobile phone surveys?

Random digit dial surveys with mobile phones risk under-representation of women. To address this, we compare the characteristics of women recruited directly with those of women recruited through referrals from male household members. The referral process improves representation of vulnerable groups, such as young women, the asset poor, and those living in areas with low connectivity. Among mobile phone users, we show a referral (rather than a direct dial) protocol includes more nationally representative proportions of women with these attributes. While seeking intra-household referrals may improve representation, we show that it does so at a higher cost.

Activation of the cytosolic calcium-independent phospholipase A2 ß isoform contributes to TRPC6 externalization via release of arachidonic acid.

During vascular interventions, oxidized low-density lipoprotein and lysophosphatidylcholine (lysoPC) accumulate at the site of arterial injury, inhibiting endothelial cell (EC) migration and arterial healing. LysoPC activates canonical transient receptor potential 6 (TRPC6) channels, leading to a prolonged increase in intracellular calcium ion concentration that inhibits EC migration. However, an initial increase in intracellular calcium ion concentration is required to activate TRPC6, and this mechanism remains elusive. We hypothesized that lysoPC activates the lipid-cleaving enzyme phospholipase A2 (PLA2), which releases arachidonic acid (AA) from the cellular membrane to open arachidonate-regulated calcium channels, allowing calcium influx that promotes externalization and activation of TRPC6 channels. The focus of this study was to identify the roles of calcium-dependent and/or calcium-independent PLA2 in lysoPC-induced TRPC6 externalization. We show that lysoPC induced PLA2 enzymatic activity and caused AA release in bovine aortic ECs. To identify the specific subgroup and the isoform(s) of PLA2 involved in lysoPC-induced TRPC6 activation, transient knockdown studies were performed in the human endothelial cell line EA.hy926 using siRNA to inhibit the expression of genes encoding cPLA2α, cPLA2γ, iPLA2ß, or iPLA2γ. Downregulation of the ß isoform of iPLA2 blocked lysoPC-induced release of AA from EC membranes and TRPC6 externalization, as well as preserved EC migration in the presence of lysoPC. We propose that blocking TRPC6 activation and promoting endothelial healing could improve the outcomes for patients undergoing cardiovascular interventions.

Traditional versus developmental measures of weight suppression: Exploring their relationships with bulimic psychopathology.

OBJECTIVE: Weight suppression (WS) is related to a wide variety of eating disorder characteristics. However, individuals with eating disorders usually reach their highest premorbid weight while still developing physically. Therefore, a more sensitive index of individual differences in highest premorbid weight may be one that compares highest premorbid z-BMI to current z-BMI (called developmental weight suppression [DWS] here). METHOD: In this exploratory study, we compared the relationships between traditional weight suppression (TWS) and DWS and a variety of measures related to bulimic psychopathology in 91 females (M age, 25.2; 60.5% White), with clinical or sub-clinical bulimia nervosa. RESULTS: TWS and DWS were correlated (r = 0.40, p < 0.001). TWS was only significantly related to a measure of physical activity whereas DWS was related to 14 outcomes. DWS showed consistent positive relations with behavioural outcomes (e.g., binge eating) but consistent negative relations with cognitive/affective outcomes (e.g., weight concerns). CONCLUSIONS: Findings indicated much more consistent relationships between the novel DWS measure and bulimic characteristics than with the TWS measure. DWS showed both positive and negative relations with bulimic symptoms, though these findings require replication to confirm their validity. Consistent evidence indicated that the two WS measures served as mutual suppressor variables.

Inhibition of P110α and P110δ catalytic subunits of PI3 kinase reverses impaired arterial healing after injury in hypercholesterolemic male mice.

Endothelial cell (EC) migration is critical for healing arterial injuries, such as those that occur with angioplasty. Impaired re-endothelialization following arterial injury contributes to vessel thrombogenicity, intimal hyperplasia, and restenosis. Oxidized lipid products, including lysophosphatidylcholine (lysoPC), induce canonical transient receptor potential 6 (TRPC6) externalization leading to increased [Ca2+]i, activation of calpains, and alterations of the EC cytoskeletal structure that inhibit migration. The p110α and p110δ catalytic subunit isoforms of phosphatidylinositol 3-kinase (PI3K) regulate lysoPC-induced TRPC6 externalization in vitro. The goal of this study was to assess the in vivo relevance of those in vitro findings to arterial healing following a denuding injury in hypercholesterolemic mice treated with pharmacologic inhibitors of the p110α and p110δ isoforms of PI3K and a general PI3K inhibitor. Pharmacologic inhibition of the p110α or the p110δ isoform of PI3K partially preserves healing in hypercholesterolemic male mice, similar to a general PI3K inhibitor. Interestingly, the p110α, p110δ, and the general PI3K inhibitor do not improve arterial healing after injury in hypercholesterolemic female mice. These results indicate a potential new role for isoform-specific PI3K inhibitors in male patients following arterial injury/intervention. The results also identify significant sex differences in the response to PI3K inhibition in the cardiovascular system, where female sex generally has a cardioprotective effect. This study provides a foundation to investigate the mechanism for the sex differences in response to PI3K inhibition to develop a more generally applicable treatment option.

P110α and P110δ catalytic subunits of PI3 kinase regulate lysophosphatidylcholine-induced TRPC6 externalization.

Lipid oxidation products, including lysophosphatidylcholine (lysoPC) inhibit endothelial cell (EC) migration in vitro and impair EC healing of arterial injuries in vivo, in part by activating phosphatidylinositol 3-kinase (PI3K), which increases the externalization of canonical transient receptor potential 6 (TRPC6) channels and the subsequent increase in intracellular calcium. Inhibition of PI3K is a potential method to decrease TRPC6 activation and restore migration, but PI3K is involved in multiple intracellular signaling pathways and has multiple downstream effectors. The goal of this study is to identify the specific p110 catalytic subunit isoforms responsible for lysoPC-induced TRPC6 externalization to identify a target for intervention while minimizing impact on alternative signaling pathways. Down-regulation of the p110α and p110δ isoforms, but not the p110ß or p110γ isoforms, with small interfering RNA significantly decreased phosphatidylinositol (3,4,5)-trisphosphate production and TRPC6 externalization, and significantly improved EC migration in the presence of lysoPC. These results identify an additional role of p110α in EC and reveal for the first time a specific role of p110δ in EC, providing a foundation for subsequent in vivo studies to investigate the impact of p110 isoform inhibition on arterial healing after injury.

Membrane translocation of TRPC6 channels and endothelial migration are regulated by calmodulin and PI3 kinase activation.

Lipid oxidation products, including lysophosphatidylcholine (lysoPC), activate canonical transient receptor potential 6 (TRPC6) channels leading to inhibition of endothelial cell (EC) migration in vitro and delayed EC healing of arterial injuries in vivo. The precise mechanism through which lysoPC activates TRPC6 channels is not known, but calmodulin (CaM) contributes to the regulation of TRPC channels. Using site-directed mutagenesis, cDNAs were generated in which Tyr(99) or Tyr(138) of CaM was replaced with Phe, generating mutant CaM, Phe(99)-CaM, or Phe(138)-CaM, respectively. In ECs transiently transfected with pcDNA3.1-myc-His-Phe(99)-CaM, but not in ECs transfected with pcDNA3.1-myc-His-Phe(138)-CaM, the lysoPC-induced TRPC6-CaM dissociation and TRPC6 externalization was disrupted. Also, the lysoPC-induced increase in intracellular calcium concentration was inhibited in ECs transiently transfected with pcDNA3.1-myc-His-Phe(99)-CaM. Blocking phosphorylation of CaM at Tyr(99) also reduced CaM association with the p85 subunit and subsequent activation of phosphatidylinositol 3-kinase (PI3K). This prevented the increase in phosphatidylinositol (3,4,5)-trisphosphate (PIP3) and the translocation of TRPC6 to the cell membrane and reduced the inhibition of EC migration by lysoPC. These findings suggest that lysoPC induces CaM phosphorylation at Tyr(99) by a Src family kinase and that phosphorylated CaM activates PI3K to produce PIP3, which promotes TRPC6 translocation to the cell membrane.

Triiodothyronine and leptin repletion in humans similarly reverse weight-loss-induced changes in skeletal muscle.

Subjects maintaining a ≥10% dietary weight loss exhibit decreased circulating concentrations of bioactive thyroid hormones and increased skeletal muscle work efficiency largely due to increased expression of more-efficient myosin heavy chain (MHC) isoforms (MHC I) and significantly mediated by the adipocyte-derived hormone leptin. The primary purpose of this study was to examine the effects of triiodothyronine (T3) repletion on energy homeostasis and skeletal muscle physiology in weight-reduced subjects and to compare these results with the effects of leptin repletion. Nine healthy in-patients with obesity were studied at usual weight (Wtinitial) and following a 10% dietary weight loss while receiving 5 wk of a placebo (Wt-10%placebo) or T3 (Wt-10%T3) in a single-blind crossover design. Primary outcome variables were skeletal muscle work efficiency and vastus lateralis muscle mRNA expression. These results were compared with the effects of leptin repletion in a population of 22 subjects, some of whom participated in a previous study. At Wt-10%placebo, skeletal muscle work efficiency and relative expression of the more-efficient/less-efficient MHC I/MHC II isoforms were significantly increased and the ratio of the less-efficient to the more-efficient sarco(endo)plasmic reticulum Ca2+-ATPase isoforms (SERCA1/SERCA2) was significantly decreased. These changes were largely reversed by T3 repletion to a degree similar to the changes that occurred with leptin repletion. These data support the hypothesis that the effects of leptin on energy expenditure in weight-reduced individuals are largely mediated by T3 and suggest that further study of the possible role of thyroid hormone repletion as adjunctive therapy to help sustain weight loss is needed.

Integration of TRPC6 and NADPH oxidase activation in lysophosphatidylcholine-induced TRPC5 externalization.

Lipid oxidation products, including lysophosphatidylcholine (lysoPC), activate canonical transient receptor potential 6 (TRPC6) channels, and the subsequent increase in intracellular Ca2+ leads to TRPC5 activation. The goal of this study is to elucidate the steps in the pathway between TRPC6 activation and TRPC5 externalization. Following TRPC6 activation by lysoPC, extracellular regulated kinase (ERK) is phosphorylated. This leads to phosphorylation of p47phox and subsequent NADPH oxidase activation with increased production of reactive oxygen species. ERK activation requires TRPC6 opening and influx of Ca2+ as evidenced by the failure of lysoPC to induce ERK phosphorylation in TRPC6-/- endothelial cells. ERK siRNA blocks the lysoPC-induced activation of NADPH oxidase, demonstrating that ERK activation is upstream of NADPH oxidase. The reactive oxygen species produced by NADPH oxidase promote myosin light chain kinase (MLCK) activation with phosphorylation of MLC and TRPC5 externalization. Downregulation of ERK, NADPH oxidase, or MLCK with the relevant siRNA prevents TRPC5 externalization. Blocking MLCK activation prevents the prolonged rise in intracellular calcium levels and preserves endothelial migration in the presence of lysoPC.

The subgingival microbiome, systemic inflammation and insulin resistance: The Oral Infections, Glucose Intolerance and Insulin Resistance Study.

BACKGROUND: Inflammation might link microbial exposures to insulin resistance. We investigated the cross-sectional association between periodontal microbiota, inflammation and insulin resistance. METHODS: The Oral Infections, Glucose Intolerance and Insulin Resistance Study (ORIGINS) enrolled 152 diabetes-free adults (77% female) aged 20-55 years (mean = 34 ± 10). Three hundred and four subgingival plaque samples were analysed using the Human Oral Microbe Identification Microarray to measure the relative abundances of 379 taxa. C-reactive protein, interleukin-6, tumour necrosis factor-α and adiponectin were assessed from venous blood and their z-scores were summed to create an inflammatory score (IS). Insulin resistance was defined via the HOMA-IR. Associations between the microbiota and both inflammation and HOMA-IR were explored using multivariable linear regressions; mediation analyses assessed the proportion of the association explained by inflammation. RESULTS: The IS was inversely associated with Actinobacteria and Proteobacteria and positively associated with Firmicutes and TM7 (p-values < 0.05). Proteobacteria levels were associated with insulin resistance (p < 0.05). Inflammation explained 30-98% of the observed associations between levels of Actinobacteria, Proteobacteria or Firmicutes and insulin resistance (p-values < 0.05). Eighteen individual taxa were associated with inflammation (p < 0.05) and 22 with insulin resistance (p < 0.05). No findings for individual taxa met Bonferroni-adjusted statistical significance. CONCLUSION: Bacterial measures were related to inflammation and insulin resistance among diabetes-free adults.

Hyperkeratotic and hypertrophic lichen nitidus.

Lichen nitidus typically presents as shiny pin-head sized papules on the trunk and extremities, often affecting children and young adults. In this prototypical form, it rarely presents a diagnostic challenge being characterized by distinctive clinical and histopathologic findings. We describe a rare variant of lichen nitidus, which we term "hyperkeratotic and hypertrophic lichen nitidus."

Proopiomelanocortin, agouti-related protein, and leptin in human cerebrospinal fluid: correlations with body weight and adiposity.

Leptin and its neuronal targets, which produce proopiomelanocortin (POMC) and agouti-related protein (AgRP), regulate energy balance. This study characterized leptin, POMC, and AgRP in the cerebrospinal fluid (CSF) of 47 healthy human subjects, 23 lean and 24 overweight/obese (OW/OB), as related to BMI, adiposity, plasma leptin, soluble leptin receptor (s-OB-R), and insulin. POMC was measured since the POMC prohormone is the predominant POMC peptide in CSF and correlates with hypothalamic POMC in rodents. Plasma AgRP was similarly characterized. CSF leptin was 83-fold lower than in plasma and correlated strongly with BMI, body fat, and insulin. The relative amount of leptin transported into CSF declined with increasing BMI, ranging from 4.5 to 0.52%, consistent with a saturable transport mechanism. CSF sOB-R was 78-fold lower than in plasma and correlated negatively with plasma and CSF leptin. CSF POMC was higher in lean vs. OW/OB subjects (P < 0.001) and correlated negatively with CSF leptin (r = -0.60, P < 0.001) and with plasma leptin, insulin, BMI, and adiposity. CSF AgRP was not different in lean vs. OW/OB; however, plasma AgRP was higher in lean subjects (P = 0.001) and correlated negatively with BMI, adiposity, leptin, insulin, and HOMA (P < 0.005). Thus, CSF measurements may provide useful biomarkers for brain leptin and POMC activity. The striking negative correlation between CSF leptin and POMC could be secondary to leptin resistance and/or neuronal changes associated with obesity but may also indicate that POMC plays a primary role in regulating body weight and adiposity. The role of plasma AgRP as a neuroendocrine biomarker deserves further study.

Hypercholesterolemia inhibits re-endothelialization of arterial injuries by TRPC channel activation.

OBJECTIVE: After arterial injury, endothelial cell (EC) migration is essential for healing, but lipid oxidation products activate TRPC6 and TRPC5 ion channels, leading to increased intracellular calcium and inhibition of EC migration in vitro. The objective of this study was to further evaluate the role of TRPC channels in EC migration in vitro and to validate in vitro findings in an in vivo model. METHODS: Mouse aortic ECs were cultured, and the effect of lysophosphatidylcholine, the major lysophospholipid in oxidized low-density lipoprotein, on migration was assessed in a razor-scrape assay. EC healing after a carotid injury with electrocautery was evaluated in wild-type (WT), TRPC6(-/-), and TRPC5(-/-) mice receiving either a chow or high-cholesterol (HC) diet. RESULTS: Lysophosphatidylcholine inhibited EC migration of WT ECs to 22% of baseline and of TRPC5(-/-) ECs to 53% of baseline but had minimal effect on TRPC6(-/-) EC migration. Hypercholesterolemia severely impaired EC healing in vivo, with 51.4% ± 1.8% and 24.9% ± 2.0% of the injury resurfaced with ECs at 5 days in chow-fed and HC-fed WT mice, respectively (P < .001). Hypercholesterolemia did not impair healing in TRPC6(-/-) mice, with coverage of 48.4% ± 3.4% and 46.8% ± 1.6% in chow-fed and HC-fed TRPC6(-/-) mice, respectively. Hypercholesterolemia had a reduced inhibitory effect in TRPC5(-/-) mice, with EC coverage of 51.7% ± 3.0% and 37.% ± 1.4% in chow-fed and HC-fed TRPC5(-/-) mice, respectively. CONCLUSIONS: Results suggest that activation of TRPC6 and TRPC5 channels is the key contributor to impaired endothelial healing of arterial injuries in hypercholesterolemic mice.