Fatty Acid Binding Protein Research Articles

Semaglutide modulates adipogenic differentiation and extracellular acidification in epicardial (EAT) and subcutaneous (SAT) adipose tissue stromal cells from patients with cardiovascular disease

Abstract Backround Cardiovascular disease (CVD) is the main cause of death in the world. One of the known risk factors is the epicardial fat (EAT) accumulation, which is around the myocardium and coronaries playing a paracrine role over them. Although mature and functional adipocytes are involved in energy balance and glucose metabolism, the hypertrophic state increases the production of fatty acid binding protein 4 (FABP4), which is a pro-inflammatory adipokine, with consequences on extracellular acidification. Recent data shows that glucagon-like peptide receptor agonists 1 (GLP1ra) drug improves the insulin response and reduces EAT thickness. Although GLP1ra has a direct effect on hypothalamus for reducing food intake, this drug might play a direct role on adipogenesis process in this fat stromal cells. Purpose Our study aims to demonstrate the effect of semaglutide on adipogenesis and metabolism in epicardial and subcutaneous stromal cells from patients with cardiovascular disease. Methods The study was approved by the Galician Research Ethics Committee, and subcutaneous adipose tissue (SAT) and EAT samples from 17 patients were obtained undergoing open-heart surgery with informed consent. Stromal cells from biopsies were isolated and cultured. Adipogenesis was induced for 15 days with or without 1 nM semaglutide, given by Novo-Nordisk (Bagsværd, Denmark), using an adipogenesis cocktail. Cells were lysed and RNA was isolated for RT-qPCR. Target genes were amplified for Glucagon like peptide 1- receptor (GLP1R), differentiation, adipogenesis, glucose metabolism and cellular markers. Extracellular acidification rate was measured with glycolytic rate assay on Seahorse. Lipids accumulation was tested by AdipoRed staining. Results Stromal cells from both tissues express GLP1R but higher differentiation factor (PGC1α) was detected in SAT compared to EAT (p=0.02), as well as adipogenesis induction. After semaglutide treatment, we observed a downregulation of FABP4 and GLUT1 in EAT (p=0.01 and p=0.02, respectively). Despite FABP4 was not modulated on SAT, there was a reduction of PGC1α levels. (p=0.02). Since glitazones upregulate PGC1α, which is used for adipogenesis induction, these results might suggest the counteract mechanism of semaglutide. The metabolism assay showed that semaglutide reduces extracellular acidification rate in EAT cells (p=0.04) and oxidative glycolysis with semaglutide treatment (p=0.003) but not in SAT cells. Conclusions Semaglutide reduces adipogenesis, through modulation of PGC1α transcription factor in EAT from patients with cardiovascular disease and extracellular acidification and oxidative glycolysis. These results might help to understand one of the mechanisms associated with EAT reduction in patients with semaglutide treatment.

Comparing de novo heart failure and acute decompensated heart failure using a proteomic approach

Abstract Background Acute heart failure (HF) is defined as new or worsening symptoms of HF and stands as the most common cause of unscheduled hospital admission in patients above the age of 65. Acute HF can be classified into de novo HF (DNHF), defined as no previous history of HF, and acutely decompensated HF (ADHF), defined as worsening symptoms of HF in individuals with a prior diagnosis of HF. Clinically, it is relevant to distinguish ADHF from DNHF as they differ regarding aetiology, comorbidities, mortality, and morbidity. The aim of this study was to compare DNHF and ADHF using a proteomic approach. Method Using a proximity extension assay in a Swedish HF cohort, a total of 324 individuals hospitalized for acute HF underwent proteomic analysis of 92 proteins. The population was categorized into DNHF and ADHF, subsequently comparing normally distributed proteins using an independent samples t-test. Non-normally distributed proteins were compared using the Mann-Whitey U-test. To adjust for multiple testing, Benjamini Hochberg method was applied with a false discovery rate of 5%. Fold change was calculated by subtracting the mean or median protein concentration in ADHF from DNHF. As protein concentrations are expressed on a log2-scale, the difference between the groups equals the fold change. Proteins were considered differentially expressed at a fold change threshold of 1.15. The proteins that met a cut-off, were thereafter analysed with a pathway enrichment analysis using Reactome (only a corrected p-value ≤0.05 was considered significant). Results Complete data was available for n=317 (30.3% women; mean age 74.6) individuals (Table 1). After FDR adjustment, differential protein expression analysis yielded 56 differentially expressed proteins. After applying the fold change threshold, 51 proteins were significantly up regulated in ADHF compared to DNHF and one (Paraoxonase 3) was significantly downregulated. The most prominently up-regulated protein was fatty acid binding protein-4 (FABP4) (fold change 1.68, p <0.001). The largest number of proteins were related to neutrophil degranulation (Figure 1). Conclusion In patients hospitalized for acute HF, we identified several common pathways of the proteins differentially expressed in DNHF compared with ADHF. Neutrophil degranulation was related to the largest number of proteins. The most prominently up regulated protein was FABP4. These findings may inspire future investigation into the different underlying molecular mechanisms in ADHF and DNHF and reveal potentially different targets of treatment between the two conditions.Figure 1.Pathway enrichment analysis

An Elevated FIB-4 Score is associated with the severity of heart failure

Abstract Background Liver disease and heart failure (HF) are known to be closely associated. Non-invasive tests (NIT), such as the FIB-4 score, have been recommended by different guidelines to rule out advanced liver fibrosis and to stratify the risk of liver-related outcomes in patients with chronic liver diseases. Purpose Thus, our goal was to evaluate the connection between the FIB-4 index, heart failure, associated comorbidities, and cardiological biomarkers that predict the risk of liver fibrosis in patients with heart failure. Methods HF patients hospitalized in the cardiology department were divided into a group with an FIB-4 index <1.3 (indicating a low risk of liver fibrosis) (n=53) and a group with an FIB-4 index ≥1.3 (indicating intermediate and high risk of fibrosis) (n=59). Clinical examinations, laboratory results, echocardiography with Vivid E95-GE Healthcare, non-invasive body mass analysis with Body Composition Analyzer (Tanita Pro), and measurements of NT-proBNP, growth differentiation factor 15 (GDF-15), galectin-3, fatty acid-binding protein (FABP), copeptin, and vascular endothelial growth factor (VEGF) concentrations were performed. Results The patients with an FIB-4 index ≥1.3 had significantly higher: left ventricular volume index (LAVI) (p=0.004), E/E’ ratio (p=0.004) and lower left ventricular ejection fraction (p=0.003) compared to group with low risk of liver fibrosis. There were no differences in body mass compartments between groups except for ECW/TBW (%) - an index of body water distribution, which was lower in low-risk liver fibrosis group (p=0.0002). Patients with an FIB-4 index ≥1.3 had also lower: GFR MDRD (median 59.95 vs 85.1 mL/min/1.73 m²; p<0.001), total cholesterol (116.5 vs 15 mg/dL; p=0.002), LDL cholesterol (median 56 vs 93 mg/dL; p<0.0001) and HDL cholesterol (median 39 vs 47 mg/dL; p=0.03). Regarding heart failure biochemical biomarkers, patients with low risk of liver fibrosis had significantly lower level of NT-proBNP (median 37 vs 161 pg/ml; p<0.0001), GDF-15 (median 399.6 vs 898.9 pg/ml; p<0.0001) and FABP (median 101 vs 264,7 pg/ml; p=0.04). In a multiple logistic regression model the factors that were independently associated with the risk of liver fibrosis in HF patients based on an FIB-4 index were GDF-15 >724 pg/ml (OR 33.7, 95%CI: 6.5-174.2; p=0.0001), and NT-proBNP >129 pg/ml (OR 19.9, 95% CI: 3.8-103; p=0.0001) (Figure 1) Conclusion Our study suggests association between an elevated FIB-4 score and heart functions, and kidney impairment with fluid overload but not with higher total and low density cholesterols fractions or percentage of fat. Higher GDF-15 and NT-proBNP levels are independently associated with the risk of liver fibrosis based on an FIB-4 index. FIB-4 index in HF patients is an easy method to monitor the risk of liver fibrosis and might help to predict the HF progression and CVD complications.

CSTB, FABP4, IBP-1 and ST2 are strong predictors of mortality after transcatheter edge-to-edge mitral valve repair

Abstract Introduction Various clinical characteristics have emerged as prognostic factors in patients undergoing transcatheter edge-to-edge mitral valve repair (M-TEER). The use of biomarkers for outcome prediction has enormous potential. The goal of this study was to identify novel biomarkers linked with adverse events after M-TEER. Methods We prospectively included 242 patients undergoing M-TEER at our center and obtained pre-procedural blood samples for biomarker analysis. Additionally, 94 follow-up samples were taken three months after M-TEER. A commercial multiplex protein assay (Cardiovascular III, Olink, Uppsala, Sweden) was used to quantify expression levels of 92 defined biomarkers. We analyzed differences in biomarker expression levels between patients that had died within one year after M-TEER and patients that had survived. Results 39 patients (16.3%) had died within one year after M-TEER. In these patients the most significantly upregulated biomarkers were NT-proBNP (expression 3.0-fold compared to survivors, p < 0.001), Cystatin B (CSTB; 2.0-fold, p < 0.001), fatty acid binding protein 4 (FABP4; 2.0-fold, p < 0.001), insulin-like growth factor-binding protein 1 (IBP-1; 1.9-fold, p < 0.001) and suppression of tumourigenicity 2 (ST2; 1.7-fold, p < 0.001). In non-survivors, expression levels of NT-proBNP (6.1-fold, p = 0.036), CSTB (3.2-fold, p = 0.050), FABP4 (3.7-fold, p = 0.037) and ST2 (2.1-fold, p = 0.017) were persistently elevated at the time of follow-up. Since its prognostic impact has already been described elsewhere, NT-proBNP was excluded from further analysis. Kaplan Meier analysis for 1-year mortality was carried out using tertiles of the respective biomarker expression levels. Mortality risk increased significantly with rising expression levels (CSTB: 3.4% in tertile 1, 12.2% in tertile 2, 37.9% in tertile 3; FABP4: 5.1%, 14.2% and 31.7%; IBP-1: 3.3%, 13.2% and 36.2%; ST2: 4.9%, 11.9% and 36.7%; p by log-rank-test < 0.001 for all biomarkers). Patients in which all 4 biomarkers were elevated to the highest tertile had an excessively high mortality risk of 52.9 vs. 13.5% (p by log-rank-test < 0.001). Receiver operating characteristic (ROC) analysis suggested higher predictive performances for mortality of all 4 biomarkers as compared to the EuroSCORE II (CSTB: area under the curve (AUC) 78.1%, 95% CI 70.7 – 85.5%; FABP4: AUC 71.6%, 95% CI 63.1 – 80.0%; IBP-1: AUC 73.9%, 95% CI 65.7 – 82.1%; ST2: AUC 76.2%, 95% CI 68.5 – 84.0%; EuroSCORE II: AUC 68.4%, 95% CI 59.3 – 77.5%). Conclusion This analysis has revealed novel biomarkers (CSTB, FABP4, IBP-1, ST2), which so far have not been characterized in M-TEER and suggests significant prognostic implications. Predictive performance of each of the respective biomarkers was superior to the most commonly used pre-operative risk stratification tool: the surgical EuroSCORE II. This hypothesis-generating study warrants further examination of these promising biomarkers.

Regulating lipid metabolism in osteoarthritis: a complex area with important future therapeutic potential

Background Osteoarthritis (OA), which is characterized by pain, inflammation and pathological changes, is associated with abnormal lipid metabolism. Extensive studies have been conducted on the potential functions of lipids including cholesterol, fatty acids (FAs) and adipokines. Materials and Methods By searching and screening the literature included in the PubMed and Web of Science databases from 1 January 2019 to 1 January 2024, providing an overview of research conducted on lipid metabolism and OA in the last 5 years. Results In addition to adiponectin, several studies on the effects of lipid metabolism on OA have been consistent and complementary. Total cholesterol, triglycerides, low-density lipoprotein cholesterol, adipsin, leptin, resistin, saturated FAs, monounsaturated FAs, FA-binding protein 4 and the ratios of the FAs hexadecenoylcarnitine (C16:1) to dodecanoylcarnitine and C16:1 to tetradecanoylcarnitine induced mostly deleterious effects, whereas high-density lipoprotein cholesterol and apolipoprotein A/B/D had a positive impact on the health of joints. The situation for polyunsaturated FAs may be more complicated, as omega-3 increases the genetic susceptibility to OA, whereas omega-6 does the opposite. Conclusion: Alterations in lipid or adipokine levels and the resulting pathological changes in cartilage and other tissues (such as bone and synovium) ultimately affect joint pain, inflammation and cartilage degradation. Lipid or adipokine regulation has potential as a future direction for the treatment of OA, this potential avenue of OA treatment requires high-quality randomized controlled trials of combined lipid regulation therapy, and more in-depth in vivo and in vitro studies to confirm the underlying mechanism.

Prognostic utility of heart-type fatty acid binding protein in patients with cardiac amyloidosis

Abstract Background Heart-type fatty acid binding protein (H-FABP) is a biomarker that has been shown to provide long-term prognostic information in patients with heart failure (HF), yet its role in patients with cardiac amyloidosis (CA) is unknown. Purpose We aim to investigate the association of H-FABP levels with prognosis in patients with CA. Methods Consecutive patients diagnosed with cardiac amyloidosis from October 2015 to May 2022 at Heart Failure Center, of our hospital were enrolled. Patients were categorized into 2 categories based on H-FABP levels measured in the baseline blood sample: < or = 7 ng/ml (low H-FABP), >7 ng/ml (high H-FABP). Univariate and multivariate Cox models were used to identify predictors of survival. Kaplan-Meier analysis was performed to compare survival between patients with low or high H-FABP. Results Overall, ninety-five patients were included. H-FABP was elevated (>7 ng/ml) in 37 patients (39%). Patients with high H-FABP were more likely to present with higher levels of high-sensitivity troponin-T (hs-TNT)(0.17ng/mL vs. 0.11ng/mL, p =0.01) and higher levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) (18098.76pg/mL vs. 6211.69pg/mL, p<0.001). Patients were followed for an average follow-up period of 440 days, in which 53 (56%) patients died. Univariate and multivariate analysis demonstrated that H-FABP levels (HR 1.48, 95% CI 1.03-2.13, per 1-SD greater) was independently associated with prognosis, even after adjusting for NT-proBNP, hs-TNT and renal function. Conclusions Elevation of H-FABP is associated with an increased risk of death in patients with cardiac amyloidosis. H-FABP can serve as a novel biomarker independent of other established predictors for prognosis in cardiac amyloidosis.Kaplan-Meier curves for overall survival

The potential value of fatty acid binding protein 1 in Chronic HBV-related liver disease progression assessment

The potential value of fatty acid binding protein 1 in Chronic HBV-related liver disease progression assessment

Gut microbiota-derived acetic acids promoted sepsis-induced acute respiratory distress syndrome by delaying neutrophil apoptosis through FABP4

In patients with sepsis, neutrophil apoptosis tends to be inversely proportional to the severity of sepsis, but its mechanism is not yet clear. This study aimed to explore the mechanism of fatty acid binding protein 4 (FABP4) regulating neutrophil apoptosis through combined analysis of gut microbiota and short-chain fatty acids (SCFAs) metabolism. First, neutrophils from bronchoalveolar lavage fluid (BALF) of patients with sepsis-induced acute respiratory distress syndrome (ARDS) were purified and isolated RNA was applied for sequencing. Then, the cecal ligation and puncture (CLP) method was applied to induce the mouse sepsis model. After intervention with differential SCFAs sodium acetate, neutrophil apoptosis and FABP4 expression were further analyzed. Then, FABP4 inhibitor BMS309403 was used to treat neutrophils. We found CLP group had increased lung injury score, lung tissue wet/dry ratio, lung vascular permeability, and inflammatory factors IL-1β, TNF-α, IL-6, IFN-γ, and CCL3 levels in both bronchoalveolar lavage fluid and lung tissue. Additionally, FABP4 was lower in neutrophils of ARDS patients and mice. Meanwhile, CLP-induced dysbiosis of gut microbiota and changes in SCFAs levels were observed. Further verification showed that acetic acids reduced neutrophil apoptosis and FABP4 expression via FFAR2. Besides, FABP4 affected neutrophil apoptosis through endoplasmic reticulum (ER) stress, and neutrophil depletion alleviated the promotion of ARDS development by BMS309403. Moreover, FABP4 in neutrophils regulated the injury of RLE-6TN through inflammatory factors. In conclusion, FABP4 affected by gut microbiota-derived SCFAs delayed neutrophil apoptosis through ER stress, leading to increased inflammatory factors mediating lung epithelial cell damage.

Balancing act: How cholesterol and phospholipids influence juvenile mud crab Scylla paramamosain growth and lipid metabolism

A 2 × 3 two-factor experiment was designed to assess the effects of dietary cholesterol (CHO) and phospholipids (PLs) on growth and lipid metabolism in early juvenile mud crabs (0.01 g crab−1). The experimental diets were designed with two CHO levels: 0.40 % (LCH) and 0.80 % (HCH), and three PLs levels: 1.80 % (LPL), 2.50 % (MPL), and 3.20 % (HPL). The 58-day aquaculture trial demonstrated that the LCH-HPL group achieved the best growth performance in mud crabs, characterized by the highest final body weight, weight gain, and specific growth rate. Regarding whole-body composition, dietary PLs increased total cholesterol (T-CHO), PLs, triglyceride (TG), and crude lipid content in the LCH groups. Mud crabs in the HCH groups had a higher proportion of saturated fatty acids, a lower proportion of monounsaturated fatty acids, and increased gene expression of sterol regulatory element binding protein 1c (srebp-1c) and fatty acid synthase (fas) compared to those in the LCH groups. As the dietary PLs increased, mud crabs in the LCH groups exhibited up-regulation in the expression of genes, including srebp-1c, fas, elongation of very long-chain fatty acid protein 4 (elovl4), elovl6, and Δ9-fatty acid desaturase (Δ9-fad). In the HCH groups, elevated dietary PLs resulted in the down-regulation of fatty acid binding protein (fabp) gene expression. In addition, high levels of dietary CHO and PLs (HCH-HPL) inhibited the catalase activity of mud crabs, resulting in a significant increase in the malondialdehyde content. Correlation analysis revealed that dietary CHO was positively correlated with the expression of long-chain polyunsaturated fatty acids synthesizing genes, and dietary PLs were positively correlated with the whole-body lipid content of mud crabs. Additionally, a positive correlation was found between the growth performance and whole-body content of crude protein, crude lipid, and antioxidant capacity in mud crabs.

Effects of endurance exercise under hypoxic conditions on the gastric emptying rate and intestinal cell damage.

The present study examined the effects of gastric emptying rate and intestinal cell damage following a single session of endurance exercise under "hypoxic" or "normoxic" conditions at the same relative intensity. Eleven healthy males performed two trials on different days, consisting of a 60min run on a treadmill at 70% maximal running velocity (vMax) while inspiring hypoxic (FiO2: 14.5%; HYP) or normoxic air (FiO2: 20.9%; NOR). The average running velocity was 11.4 ± 0.7km/h in NOR and 10.8 ± 0.5km/h in HYP, respectively. Venous blood samples were collected to evaluate plasma intestinal fatty acid binding protein (I-FABP) as an indicator of exercise-induced intestinal cell damage. The gastric emptying rate was determined by the 13C-sodium acetate breath test. Running velocities at 70% vMax and arterial oxygen saturation were significantly lower under HYP than NOR (p < 0.001). Peak heart rate and rating of perceived exertion during exercise did not differ significantly between the trials. Maximum 13C excretion time (an indication of the gastric emptying rate) was significantly delayed in the HYP (NOR: 38.5 ± 5.0min, HYP: 45.5 ± 9.6min; p = 0.010). Furthermore, the score of nausea increased slightly, but increased significantly after exercise only in the HYP (p = 0.04). However, exercise-induced changes in plasma I-FABP, adrenaline, and noradrenaline concentrations did not differ significantly between the two trials. These results suggest that endurance exercise under hypoxic conditions impairs digestive function in the stomach compared to exercise under normoxic conditions performed at the same relative intensity.

RNA-seq and whole-genome re-sequencing reveal Micropterus salmoides growth-linked gene and selection signatures under carbohydrate-rich diet and varying temperature

This study was performed on Micropterus salmoides to determine growth-linked gene and single nucleotide polymorphism (SNP) markers under carbohydrate diet and varying temperature through RNA-seq and whole-genome re-sequencing. The results showed that growth-related genes were primarily enriched in the fat digestion and absorption signaling pathway, playing a role in lipid transport and metabolism. Fatty acid binding protein 6, bile salt-activated lipase-like, lysophosphatidylcholine acyltransferase 2, phospholipase A2, minor isoenzyme-like, and phospholipase A2, group IB (pancreas) were identified as the crucial genes. The differentially expressed genes between high and low temperatures were enriched in the pentose phosphate pathway, with carbohydrate transport and metabolism were most affected by temperature. Major facilitator superfamily domain containing 10, phosphogluconate dehydrogenase, fructose-1,6-bisphosphatase 1a, and spinster homolog 3 transcript variant X1(spns3) were the shared genes affected by temperature. From all the common genes, 10 growth-associated SNP markers were identified. The TT genotype at rs7781 was associated with lower body weight, while AA genotype at rs31434173 and CC genotype at rs31435313 showed positive correlation with body weight. Analogously, the GG genotype at rs31436887 and AA genotype at rs31438769 also found to characterize better growth performance. At low temperature, individuals with the AA genotype at rs11506587 and rs31435313 exhibited the slowest growth. For the genotypes labeled with rs11510589, the GG individual grew faster than the AA individual, whereas the opposite phenomenon occurred in these genotypes when labeled with rs11511314. The genotypes at rs32970704 and rs32967921 showed no growth correlation. The AA genotype at rs31435313 in spns3 had the slowest growth under a carbohydrate-rich diet regardless of the temperature. Our study presents candidate genes and SNP markers associated with growth influenced by carbohydrate and temperature, providing basis for the development of M. salmoides strain that better accepts carbohydrate diets at varying temperature.

Reduced glutathione attenuates pediatric sepsis-associated encephalopathy by inhibiting inflammatory cytokine release and mitigating lipid peroxidation-induced brain injury.

Sepsis-associated encephalopathy (SAE) is a severe complication of sepsis. Reduced glutathione (GSH) has antioxidant properties and is used as a neuroprotective agent in some studies. However, research on the application of exogenous GSH in the treatment of SAE is limited. This study aimed to determine the effects of exogenous GSH in pediatric SAE patients and mice. We evaluated clinical parameters, inflammatory factors, and oxidative stress before and after GSH treatment. The clinical trials demonstrated that GSH treatment improved brain damage markers (S-100 beta protein, brain fatty acid-binding protein), increased neurological status scores (Glasgow coma scale), and reduced Pediatric Risk of Mortality III scores in children with SAE. GSH treatment also significantly reduced the levels of inflammatory factors (interleukin-6, tumor necrosis factor-α) and decreased lipid peroxidation (superoxide dismutase). Additionally, GSH reduced lipid peroxidation resulting from abnormal lipid metabolism, as indicated by the levels of acyl-CoA synthetase long-chain family member 4, lysophosphatidylcholine acyltransferase 3, and glutathione peroxidase 4. In-vivo experiments showed that the neuroprotective effect of GSH was dose-dependent, with better effects observed at medium and high doses. Furthermore, GSH alleviated brain damage, suppressed the release of inflammatory factors, and inhibited lipid peroxidation in SAE mice. The animal experiments also showed that GSH reduces lipid peroxidation through the 15-lipoxygenase/phosphatidylethanolamine binding protein 1/glutathione peroxidase 4 pathway. Our study suggests that exogenous GSH has neuroprotective effects in pediatric SAE. These findings provide a basis for the potential use of GSH as a therapeutic method for SAE.

FABP5+ macrophages contribute to lipid metabolism dysregulation in type A aortic dissection

Type A aortic dissection (TAAD) is an acute onset disease with a high mortality rate. TAAD is caused by a tear in the aortic intima and subsequent blood infiltration. The most prominent characteristics of TAAD are aortic media degeneration and inflammatory cell infiltration, which disturb the structural integrity and function of nonimmune and immune cells in the aortic wall. However, to date, there is no systematic evaluation of the interactions between nonimmune cells and immune cells and their effects on metabolism in the context of aortic dissection. Here, multiomics, including bulk RNA-seq, single-cell RNA-seq, and lipid metabolomics, was applied to elucidate the comprehensive TAAD lipid metabolism landscape. Normally, monocytes in the stress response state secrete a variety of cytokines. Injured fibroblasts lack the ability to degrade lipids, which is suspected to contribute to a high lipid environment. Macrophages differentiate into fatty acid binding protein 5-positive (FABP5+) macrophages under the stimulation of metabolic substrates. Moreover, the upregulation of Fabp5+ macrophages were retrospectively validated in TAAD model mice and TAAD patients. Finally, Fabp5+ macrophages can generate a wide range of proinflammatory cytokines, which possibly contribute to TAAD pathogenesis.

Elevated intestinal fatty acid-binding protein levels as a marker of portal hypertension and gastroesophageal varices in cirrhosis

We measured intestinal fatty acid-binding protein (I-FABP) levels, a useful marker of small intestinal mucosal injury, in patients with cirrhosis to determine their relationship with liver function and complications. This cross-sectional study included 71 patients with cirrhosis admitted for treatment of cirrhotic complications or hepatocellular carcinoma (cohort A) and 104 patients with cirrhosis who received direct-acting antiviral therapy for HCV (cohort B). I-FABP levels, measured by ELISA, were evaluated relative to hepatic reserve and compared with non-invasive scoring systems for diagnostic performance in cirrhotic complications. The median I-FABP level in both cohorts were significantly elevated in patients with reduced hepatic reserve (CTP grade A/BC cohort A, 2.33/3.17 ng/mL, p = 0.032; cohort B, 2.46/3.64 ng/mL, p = 0.008) and complications with gastroesophageal varices (GEV; GEV (-)/(+) cohort A, 1.66/3.67 ng/mL, p < 0.001; cohort B, 2.32/3.36 ng/mL; p = 0.003). Further, multiple logistic regression analysis identified I-FABP as the only factor contributing to GEV presence in both cohorts, which outperformed non-invasive scoring systems for GEV diagnosis (sensitivity 84.6%; specificity 84.2%; sensitivity 69.6%; specificity 63.8%, respectively). In conclusion, elevated small-intestinal mucosal injury in patients with cirrhosis was related to reduced hepatic reserve and GEV presence. I-FABP levels reflect portal hypertension and may be useful in cirrhosis management.

Potential toxicity of Graphene (Oxide) quantum dots to human intestinal fatty acid binding protein (HIFABP) via obstructing the protein’s openings

Graphene quantum dots (GQDs) have garnered significant attention across numerous fields due to their ultrasmall size and exceptional properties. However, their extensive applications may lead to environmental exposure and subsequent uptake by humans. Yet, conflicting reports exist regarding the potential toxicity of GQDs based on experimental investigations. Therefore, a comprehensive understanding of GQD biosafety requires further microscopic and molecular-level investigations. In this study, we employed molecular dynamics (MD) simulations to explore the interactions between GQDs and graphene oxide quantum dots (GOQDs) with a protein model, the human intestinal fatty acid binding protein (HIFABP), that plays a crucial role in mediating the carrier of fatty acids in the intestine. Our MD simulation results reveal that GQDs can be adsorbed on the opening of HIFABP, which serves as an entrance for the fatty acid molecules into the protein’s interior cavity. This adsorption has the potential to obstruct the opening of HIFABP, leading to the loss of its normal biological function and ultimately resulting in toxicity. The adsorption of GQDs is driven by a combination of van der Waals (vdW), π-π stacking, cation-π, and hydrophobic interactions. Similarly, GOQDs also exhibit the ability to block the opening of HIFABP, thereby potentially causing toxicity. The blockage of GOQDs to HIFABP is guided by a combination of vdW, Coulomb, π-π stacking, and hydrophobic interactions. These findings not only highlight the potential harmful effects of GQDs on HIFABP but also elucidate the underlying molecular mechanism, which provides crucial insights into GQD toxicology.

Data-independent acquisition proteomic analysis of the brain microvasculature in Alzheimer’s disease identifies major pathways of dysfunction and upregulation of cytoprotective responses

Brain microvascular dysfunction is an important feature of Alzheimer’s disease (AD). To better understand the brain microvascular molecular signatures of AD, we processed and analyzed isolated human brain microvessels by data-independent acquisition liquid chromatography with tandem mass spectrometry (DIA LC–MS/MS) to generate a quantitative dataset at the peptide and protein level. Brain microvessels were isolated from parietal cortex grey matter using protocols that preserve viability for downstream functional studies. Our cohort included 23 subjects with clinical and neuropathologic concordance for Alzheimer’s disease, and 21 age-matched controls. In our analysis, we identified 168 proteins whose abundance was significantly increased, and no proteins that were significantly decreased in AD. The most highly increased proteins included amyloid beta, tau, midkine, SPARC related modular calcium binding 1 (SMOC1), and fatty acid binding protein 7 (FABP7). Additionally, Gene Ontology (GO) enrichment analysis identified the enrichment of increased proteins involved in cellular detoxification and antioxidative responses. A systematic evaluation of protein functions using the UniProt database identified groupings into common functional themes including the regulation of cellular proliferation, cellular differentiation and survival, inflammation, extracellular matrix, cell stress responses, metabolism, coagulation and heme breakdown, protein degradation, cytoskeleton, subcellular trafficking, cell motility, and cell signaling. This suggests that AD brain microvessels exist in a stressed state of increased energy demand, and mount a compensatory response to ongoing oxidative and cellular damage that is associated with AD. We also used public RNAseq databases to identify cell-type enriched genes that were detected at the protein level and found no changes in abundance of these proteins between control and AD groups, indicating that changes in cellular composition of the isolated microvessels were minimal between AD and no-AD groups. Using public data, we additionally found that under half of the proteins that were significantly increased in AD microvessels had concordant changes in brain microvascular mRNA, implying substantial discordance between gene and protein levels. Together, our results offer novel insights into the molecular underpinnings of brain microvascular dysfunction in AD.

L-Carnitine: A New Therapeutic Option for the Prevention of Atrial Fibrillation in Non-Cardiac Surgery-A Single-Group Interventional Pilot Study.

Background: L-carnitine is essential in lipid metabolism and reportedly has preventive effects for arrhythmia. Our objective was to examine the incidence of postoperative atrial fibrillation (POAF) and changes in serum biomarker levels following perioperative L-carnitine administration in patients with lung cancer. Methods: Thirteen patients undergoing a lobectomy with preoperative serum brain natriuretic peptide levels >24 pg/mL were perioperatively administered L-carnitine for 5 days (3 g/3×). Accurate 95% confidence intervals (CI) for POAF incidence were calculated. Serum biomarkers for POAF in lung cancer and target proteins for L-carnitine were evaluated by using open-source data from proteomic analysis. Results: The incidence of POAF was 38.5% (95% CI 13.9%-68.4%). Fatty acid-binding protein 4 (FABP4) was selected as a candidate biomarker from 1472, 63, and 26 proteins related to lung cancer, L-carnitine, and AF, respectively. A positive correlation was observed between the predicted POAF incidence rate and preoperative FABP4 levels (Pearson's r = 0.5183). The mean change in serum FABP4 after L-carnitine administration for 5 days was -2.9 ng/mL (95% CI -4.9 to -0.89 ng/mL). Conclusions: The incidence of POAF after a lobectomy was 38.5% after the perioperative administration of L-carnitine for patients at a high risk of POAF. The serum FABP4 level demonstrates potential as a candidate biomarker for POAF prediction.

Association of circulating adipokines with metabolic measures among people with HIV: Moderating effects of alcohol use.

People with HIV (PWH) are at increased risk for cardiometabolic comorbidities. We have reported that lifetime alcohol use among people with HIV (PWH) is associated with increased risk for metabolic syndrome. Dysfunctional adipose tissue and altered circulating adipokines mediate metabolic dysregulation. The objective of this study was to determine the associations of circulating adipokine concentration with metabolic measures, and the moderating effects of lifetime and recent alcohol use in PWH. This is a cross-sectional analysis of data from 357 PWH at their baseline visit of the longitudinal New Orleans Alcohol and HIV (NOAH) study. The concentrations of four circulating adipokines (adiponectin, leptin, resistin, and fatty acid-binding protein 4 [FABP4]) and their associations with five metabolic measures (triglycerides, cholesterol, Hemoglobin A1c, Homeostatic Model Assessment for Insulin Resistance, and metabolic syndrome) were examined. Higher circulating adiponectin was associated with increased odds of normal triglyceride, cholesterol, and Hemoglobin A1c levels. Increased leptin and FABP4 concentrations were associated with decreased odds of normal triglyceride and cholesterol levels. Increased leptin and FABP4 concentrations were associated with increased odds of insulin resistance and meeting criteria for metabolic syndrome. Increased circulating resistin concentration was associated with decreased odds of normal triglyceride levels and increased odds of meeting criteria for metabolic syndrome. Additionally, among PWH with increased lifetime alcohol use, higher adiponectin concentration was associated with decreased odds of meeting criteria for metabolic syndrome. These data suggest the interplay between adiponectin, leptin, FABP4, and resistin may contribute to metabolic stability among PWH. Moreover, lifetime, but not recent, alcohol use moderates the relationship between adipokines and metabolic measures. These data highlight the relevance of functional adipose tissue mass and associated circulating adipokine levels in maintaining metabolic homeostasis, and its moderation by lifetime alcohol consumption.

Gastrointestinal permeability and kidney injury risk during hyperthermia in young and older adults.

We tested whether older adults, compared with young adults, exhibit greater gastrointestinal permeability and kidney injury during heat stress. Nine young (32±3 years) and nine older (72±3 years) participants were heated using a model of controlled hyperthermia (increasing core temperature by 2°C via a water-perfused suit). Gastrointestinal permeability was assessed using a multi-sugar drink test containing lactulose, sucrose and rhamnose. Blood and urine samples were assayed for markers of intestinal barrier injury [plasma intestinal fatty acid binding protein (I-FABP), plasma lipopolysaccharide binding protein (LBP) and plasma soluble cluster of differentiation 14 (sCD14)], inflammation (serum cytokines), kidney function (plasma creatinine and cystatin C) and kidney injury [urine arithmetic product of IGFBP7 and TIMP-2 (TIMP-2 × IGFBP7), neutrophil gelatinase-associated lipocalin and kidney injury molecule-1]. The lactulose-to-rhamnose ratio was increased in both young and older adults (group-wide: Δ0.11±0.11), but the excretion of sucrose was increased only in older adults (Δ1.7±1.5). Young and older adults showed similar increases in plasma LBP (group-wide: Δ0.65±0.89µg/mL), but no changes were observed for I-FABP or sCD14. Heat stress caused similar increases in plasma creatinine (group-wide: Δ0.08±0.07mg/dL), cystatin C (group-wide: Δ0.16±0.18mg/L) and urinary IGFBP7×TIMP-2 [group-wide: Δ0.64±0.95 (pg/min)2] in young and older adults. Thus, the level of heat stress used herein caused modest increases in gastrointestinal permeability, resulting in a mild inflammatory response in young and older adults. Furthermore, our data indicate that older adults might be more at risk for increases in gastroduodenal permeability, as evidenced by the larger increases in sucrose excretion in response to heat stress. Finally, our findings show that heat stress impairs kidney function and elevates markers of kidney injury; however, these responses are not modulated by age.

Fatty acid–binding protein 3 is involved in the increase in inflammatory cytokine levels during lipopolysaccharide–induced microglial activation and affects the pain behavior

Fatty acid–binding protein 3 is involved in the increase in inflammatory cytokine levels during lipopolysaccharide–induced microglial activation and affects the pain behavior