Fatty Acid Binding Protein Research Articles

High-expression of FABP4 in Tubules is a Risk Factor for Poor Prognosis in DKD Patients.

Lipid metabolism imbalance is involved in the mechanism of renal tubular injury in diabetic kidney disease (DKD). Fatty acid binding protein 4 (FABP4) has been reported to participate in cellular lipid toxicity. However, the expression of FABP4 in renal tissues of DKD and its correlation with clinical/ pathological parameters and prognosis have not been studied. A retrospective cohort study was conducted in 108 hospitalized Type 2 diabetes (T2D) patients with renal injury, including 70 with DKD and 38 with NDKD (non-DKD). Clinical features, pathological findings, and follow-up parameters were collected. Serum and urine FABP4 were detected by ELISA. An immunohistochemistry stain was used to determine FABP4 in renal tubulointerstitium. A double immunofluorescence stain was employed to assess FABP4- and CD68-positive macrophages. Correlation analysis, logistic regression models, receiver operating characteristic (ROC), and Kaplan-Meier survival curve were performed for statistical analysis. DKD patients had increased expression of FABP4 and ectopic fat deposition in tubules. As shown by correlation analyses, FABP4 expression in renal tubules was positively correlated with UNAG (r=0.589, p=0.044) and ESRD (r=0.740, p=0.004). Multivariate regression analysis revealed that UNAG level was correlated with FABP4 expression level above median value (odds ratio:1.154, 95% confidence interval:1.009-1.321, p=0.037). High-expression of FABP4 in renal tubules of DKD was at an increased risk of ESRD. Increased FABP4 expression in inflammatory cells was also associated with ESRD in DKD. High-expression of FABP4 is involved in the pathogenesis of renal tubular lipid injury and is a risk factor for poor prognosis in DKD patients.

Trajectory pattern of serially measured acute kidney injury biomarkers in critically ill patients: a prospective observational study

BackgroundThe clinical value of the trajectory of temporal changes in acute kidney injury (AKI) biomarkers has not been well established among intensive care unit (ICU) patients.MethodsThis is a single-center, prospective observational study, performed at a mixed ICU in a teaching medical institute in Tokyo, Japan. Adult ICU patients with an arterial line and urethral catheter were enrolled from September 2014 to March 2015. Patients who stayed in the ICU for less than 48 h and patients with known end-stage renal disease were excluded from the study. Blood and urine samples were collected for measurement of AKI biomarkers at 0, 12, 24, and 48 h after ICU admission. The primary outcome was major adverse kidney events (MAKE) at discharge, defined as a composite of death, dialysis dependency, and persistent loss of kidney function (≥ 25% decline in eGFR).ResultsThe study included 156 patients. Serum creatinine-based estimated glomerular filtration rate (eGFR), plasma neutrophil gelatinase-associated lipocalin (NGAL), and urinary liver-type fatty acid-binding protein (uL-FABP) were serially measured and each variable was classified into three groups based on group-based trajectory modeling analysis. While the trajectory curves moved parallel to each other (i.e., “low,” “middle,” and “high”) for eGFR and plasma NGAL, the uL-FABP curves showed distinct trajectory patterns and moved in different directions (“low and constant,” “high and exponential decrease,” and “high and exponential increase”). These trajectory patterns were significantly associated with MAKE. MAKE occurred in 16 (18%), 16 (40%), and 9 (100%) patients in the “low and constant,” “high and exponential decrease,” and “high and exponential increase” groups, respectively, based on uL-FABP levels (p-value < 0.001). The initial value and the 12-h change in uL-FABP were both significantly associated with MAKE, even after adjusting for eGFR [Odds ratio (95% confidence interval): 1.45 (1.17–1.83) and 1.43 (1.12–1.88) for increase of initial value and 12-h change of log-transformed uL-FABP by 1 point, respectively].ConclusionsTrajectory pattern of serially measured urinary L-FABP was significantly associated with MAKE in ICU patients.

Protective effect of cholecalciferol against cobalt-induced neurotoxicity in rats: ZO-1/iFABP, ChAT/AchE and antioxidant pathways as potential therapeutic targets.

Cobalt (Co) toxicity has been reported to produce central nervous system and gastrointestinal abnormalities. This study assessed the therapeutic effect of cholecalciferol (Cho) supplementation against damages caused by sub-acute (14-day) cobalt chloride (CoCl2) exposure in the brain and intestines. Thirty-five male Wistar rats were divided equally into five groups: Group I (control) received no treatment; Group II received oral CoCl2 (100 mg/kg) only; Groups III, IV, and V received 1000, 3000 and 6000 IU/kg of cholecalciferol, respectively by oral gavage, and concurrently with CoCl2. Cobalt-treated rats showed neuronal vacuolation and presence of pyknotic nuclei in the cerebral cortex and hippocampus, depletion of Purkinje cells in the cerebellum, as well as inflammation and congestion in the intestinal mucosa. Cobalt also increased brain and intestinal hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentrations, while simultaneously reducing glutathione (GSH) content, superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities. Further, CoCl2 induced increases in brain acetylcholinesterase (AchE) activity and serum zonulin (ZO-1) levels. Conversely, Cho administration suppressed CoCl2-induced damages in the brain and intestines by reducing lipid peroxidation and increasing the activities of antioxidant enzymes. Remarkably, Cho produced stimulation of brain choline acetyltransferase (ChAT) and suppression of AchE activity, along with dose-dependent reduction in serum levels of ZO-1, intestinal fatty acid-binding protein (iFABP) and nitric oxide. In conclusion, the protective role of cholecalciferol against cobalt-induced toxicity occurred via modulation of cholinergic, intestinal permeability and antioxidant pathways. The results may prove significant in the context of the role of gut-brain connections in neuroprotection.

Identification of novel biomarkers of acute phase response in chickens challenged with Escherichia coli lipopolysaccharide endotoxin

BackgroundThe chicken’s inflammatory response is an essential part of the bird’s response to infection. A single dose of Escherichia coli (E. coli) lipopolysaccharide (LPS) endotoxin can activate the acute phase response (APR) and lead to the production of acute phase proteins (APPs). In this study, the responses of established chicken APPs, Serum amyloid A (SAA) and Alpha-1-acid-glycoprotein (AGP), were compared to two novel APPs, Hemopexin (Hpx) and Extracellular fatty acid binding protein (Ex-FABP), in 15-day old broilers over a time course of 48 h post E.coli LPS challenge. We aimed to investigate and validate their role as biomarkers of an APR. Novel plant extracts, Citrus (CTS) and cucumber (CMB), were used as dietary supplements to investigate their ability to reduce the inflammatory response initiated by the endotoxin.ResultsA significant increase of established (SAA, AGP) and novel (Ex-FABP, Hpx) APPs was detected post E.coli LPS challenge. Extracellular fatty acid binding protein (Ex-FABP) showed a similar early response to SAA post LPS challenge by increasing ~ 20-fold at 12 h post challenge (P < 0.001). Hemopexin (Hpx) showed a later response by increasing ∼5-fold at 24 h post challenge (P < 0.001) with a similar trend to AGP. No differences in APP responses were identified between diets (CTS and CMB) using any of the established or novel biomarkers.ConclusionsHpx and Ex-FABP were confirmed as potential biomarkers of APR in broilers when using an E. coli LPS model along with SAA and AGP. However, no clear advantage for using either of dietary supplements to modulate the APR was identified at the dosage used.

Blood perfusion with polymyxin B immobilized columns in patients with COVID-19 requiring oxygen therapy

Extracorporeal blood purification with polymyxin B immobilized fiber column direct hemoperfusion (PMX-DHP), is reported to be effective in treating COVID-19 pneumonitis with oxygen demand. This multicenter prospective study evaluated the efficacy and safety of PMX-DHP in oxygen-requiring patients with COVID-19 admitted between September 28, 2020, and March 31, 2022. The primary endpoint was the percentage of clinical improvement 15 days after treatment. The secondary endpoint was the percentage of worsened disease status. Data from the COVID-19 patient registry were used for the synthetic control group. The improvement rate on Day 15 did not differ between PMX-treated patients and controls; however, the deterioration rate was 0.38 times lower in the PMX-treated group, and the death rates on Day 29 were 0 and 11.1% in the PMX-treated and control groups, respectively. The PMX group showed a 0.73 times higher likelihood for reduced intensive care demand, as 16.7% of PMX-treated patients and 22.8% of controls worsened. After treatment blood oxygenation improved, urinary β2-microglobulin and liver-type fatty acid-binding protein showed significant decreases, and IL-6 decreased once during treatment but did not persist. In this study, PMX treatment effectively prevented the worsening of COVID-19 pathology, accompanied by improved oxygenation. PMX treatment to remove activated cells may effectively improve patient outcomes.

FABP4 as potential indicator for GDM-induced fetal endothelial dysfunction

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DFG project no. 288034826—International Research Training Group (IRTG) 2251 Background Gestational diabetes mellitus (GDM) is linked to an elevated risk of developing cardiovascular diseases (CVD) both for the mother and the baby in later life. Previous studies have identified fatty acid-binding protein 4 (FABP4) as a prime candidate involved in the pathophysiology of GDM. FABP4 is known to promote an inflammatory response and vascular permeability, induce oxidative stress in endothelial cells (ECs), and impair the nitric oxide signaling pathway, thereby promoting endothelial dysfunction. Indeed, women with GDM exhibit elevated blood levels of FABP4, suggesting its potential as a biomarker for endothelial dysfunction and cardiovascular risk assessment in GDM. However, the role that FABP4 plays in the fetal endothelial function remains poorly understood. Purpose Thus, our aim is to understand the role of FABP4 in fetal endothelial dysfunction and its regulation to mitigate the impact of GDM on the vasculature. Methods Fetoplacental vessels and primary human umbilical vein endothelial cells (HUVECs) were isolated from placentas and umbilical cords obtained from both normoglycemic (NG) and GDM pregnancies. We also obtained the clinical data from the mothers and collected the cord blood. Total mRNA from HUVECs was used for bulk RNA sequencing to compare gene expression, while gene expression analysis in the vessels was conducted using RT-qPCR. Additionally, NG HUVECs were pooled and cultured under high laminar flow conditions (30 dyn/cm²) or subjected to various treatments, including insulin (5nM), glucose (25mM), simvastatin (10nm), or VEGF-A stimulation. Subsequent RT-qPCRs were performed to analyze the gene expression of several genes of interest. Results The bulk RNA sequencing data analysis revealed FABP4 as an overexpressed gene in GDM HUVECs compared to NG. Furthermore, the analysis of data through Gene Set Enrichment Analysis provided a list of different gene sets that are enriched in GDM samples. Among these gene sets are pathways or processes implicated in endothelial dysfunction, such as angiogenesis, PI3K/AKT/mTOR signaling, reactive oxygen species pathway, or inflammatory response. In vitro experiments provided evidence for an elevated FABP4 mRNA expression after VEGF treatment of HUVECs. Conversely, both simvastatin treatment and exposure to laminar flow reduced FABP4 mRNA expression and increased eNOS expression, suggesting a potential inhibitory effect of nitric oxide on FABP4. Conclusion We provided evidence that FABP4 could be involved in fetal GDM-induced endothelial dysfunction. Shear stress and statins might protect the endothelium against the negative impact of FABP4.

Intestinal Fatty Acid–Binding Protein as a Potential Biomarker for Gastrointestinal Complications after Complex Endovascular Aortic Surgery

This study aimed to investigate the association between intestinal fatty acid-binding protein (I-FABP), acute gastrointestinal injury (AGI) grade, and gastrointestinal (GI) complications after fenestrated or branched endovascular aortic aneurysm repair. A total of 17 patients undergoing endovascular aortic repair for thoracoabdominal, juxtarenal, suprarenal, or pararenal aneurysm between May 2017 and September 2018 were enrolled. Blood samples were collected preoperatively and during postoperative intensive care. The blood samples were analyzed for I-FABP with enzyme-linked immunosorbent assay. Gastrointestinal function was assessed according to the AGI grade every day during postoperative intensive care. Higher concentrations of I-FABP at 24hr and 48 hr correlated to higher AGI grade on postoperative days 1, 2, and 3 (P=0.032 and P=0.048, P=0.040 and P=0.018, and P=0.012 and P=0.016, respectively). Patients who developed a GI complication within 90days postoperatively had a higher overall AGI grade than those who did not develop a GI complication (P<0.001), as well as higher concentrations of I-FABP at 48 hrs (P=0.019). Patients developing GI dysfunction (AGI grade ≥2) had a higher frequency of complications (P=0.009) and longer length of stay in the intensive care unit (P=0.008). In patients undergoing endovascular aortic repair for complex aneurysm increased postoperative plasma I-FABP concentrations and postoperative GI dysfunction, evaluated using the AGI grade, were associated with GI complications, indicating that these measures may be useful in the postoperative management of these patients.

Proteomics of tumor and serum samples from isocitrate dehydrogenase-wildtype glioblastoma patients: is the detoxification of reactive oxygen species associated with shorter survival?

Proteomics has been little used for the identification of novel prognostic and/or therapeutic markers in isocitrate dehydrogenase (IDH)-wildtype glioblastoma (GB). In this study, we analyzed 50 tumor and 30 serum samples from short- and long-term survivors of IDH-wildtype GB (STS and LTS, respectively) by data-independent acquisition mass spectrometry (DIA-MS)-based proteomics, with the aim of identifying such markers. DIA-MS identified 5422 and 826 normalized proteins in tumor and serum samples, respectively, with only three tumor proteins and 26 serum proteins displaying significant differential expression between the STS and LTS groups. These dysregulated proteins were principally associated with the detoxification of reactive oxygen species (ROS). In particular, GB patients in the STS group had high serum levels of malate dehydrogenase 1 (MDH1) and ribonuclease inhibitor 1 (RNH1) and low tumor levels of fatty acid-binding protein 7 (FABP7), which may have enabled them to maintain low ROS levels, counteracting the effects of the first-line treatment with radiotherapy plus concomitant and adjuvant temozolomide. A blood score built on the levels of MDH1 and RNH1 expression was found to be an independent prognostic factor for survival based on the serum proteome data for a cohort of 96 IDH-wildtype GB patients. This study highlights the utility of circulating MDH1 and RNH1 biomarkers for determining the prognosis of patients with IDH-wildtype GB. Furthermore, the pathways driven by these biomarkers, and the tumor FABP7 pathway, may constitute promising therapeutic targets for blocking ROS detoxification to overcome resistance to chemoradiotherapy in potential GB STS.

Dipeptidyl peptidase-4 disturbs adipocyte differentiation via the negative regulation of the glucagon-like peptide-1/adiponectin-cathepsin K axis in mice under chronic stress conditions.

Exposure to chronic psychosocial stress is a risk factor for metabolic disorders. Because dipeptidyl peptidase-4 (DPP4) and cysteinyl cathepsin K (CTSK) play important roles in human pathobiology, we investigated the role(s) of DPP4 in stress-related adipocyte differentiation, with a focus on the glucagon-like peptide-1 (GLP-1)/adiponectin-CTSK axis invivo and invitro. Plasma and inguinal adipose tissue from non-stress wild-type (DPP4+/+), DPP4-knockout (DPP4-/-) and CTSK-knockout (CTSK-/-) mice, and stressed DPP4+/+, DPP4-/-, CTSK-/-, and DPP4+/+ mice underwent stress exposure plus GLP-1 receptor agonist exenatide loading for 2 weeks and then were analyzed for stress-related biological and/or morphological alterations. On day 14 under chronic stress, stress decreased the weights of adipose tissue and resulted in harmful changes in the plasma levels of DPP4, GLP-1, CTSK, adiponectin, and tumor necrosis factor-α proteins and the adipose tissue levels of CTSK, preadipocyte factor-1, fatty acid binding protein-4, CCAAT/enhancer binding protein-α, GLP-1 receptor, peroxisome proliferator-activated receptor-γ, perilipin2, secreted frizzled-related protein-4, Wnt5α, Wnt11 and β-catenin proteins and/or mRNAs as well as macrophage infiltration in adipose tissue; these changes were rectified by DPP4 deletion. GLP-1 receptor activation and CTSK deletion mimic the adipose benefits of DPP4 deficiency. Invitro, CTSK silencing and overexpression respectively prevented and facilitated stress serum and oxidative stress-induced adipocyte differentiation accompanied with changes in the levels of pref-1, C/EBP-α, and PPAR-γ in 3T3-L1 cells. Thus, these findings indicated that increased DPP4 plays an essential role in stress-related adipocyte differentiation, possibly through a negative regulation of GLP-1/adiponectin-CTSK axis activation in mice under chronic stress conditions.

Clinical determinants of blood biomarkers of atrial cardiomyopathy: results from the ISOLATION AF ablation cohort study

Abstract Background In patients with atrial fibrillation (AF), significant advances have been made in identifying biomarkers representing diverse pathophysiological pathways, such as inflammation, myocyte injury, collagen deposition, and fatty-fibrotic infiltration. Data on clinical determinants of biomarkers in patients with AF, however, are lacking. Objective Our primary aim was to explore the relationships between clinical determinants and biomarker levels in AF patients scheduled for catheter ablation. Methods A cross-sectional analysis was conducted in AF patients undergoing catheter ablation included in the prospective multicenter ISOLATION study between July 2020 and May 2022. Clinical characteristics, routine tests and blood samples were collected before ablation. Blood samples were analyzed for known and novel cardiovascular biomarkers, including Bone morphogenetic protein 10 (BMP10), Angiopoietin-2 (Ang-2), Fibroblast growth factor 23 (FGF-23), Dickkopf-related protein 3 (DKK-3), Endocan (ESM-1), Insulin-like growth factor-binding protein 7 (IGFBP-7), B-type natriuretic peptides (proBNP, NTproBNP), High sensitive Troponin-T (hsTnT)&amp;lt; Growth differentiation factor 15 (GDF-15), interleukin 6 (IL-6), Fatty acid binding protein 3 (FABP3), Cancer antigen-125 (Ca-125) (Table 1). For each biomarker we trained a lasso regression model to identify the most important clinical determinants out of all the 60 available determinants (including anthropometry, ECG, comorbidities). The strongest associations are summarized in figure 1. Results Blood samples of 508 patients were analyzed. The mean age was 63 ±9 years, and 31.1% were female. 354 patients (69.7%) had paroxysmal AF and 154 patients (30.3%) had persistent AF. Heart failure was reported in 77 patients (15.2%). 355 (72.3%) patients were in sinus rhythm during sample collection. The following clinical determinants of biomarker levels were frequently identified as important: rhythm during blood phlebotomy, age, heart failure, decreased kidney function and female sex (Figure 1). Most notably, rhythm at the time of sampling was strongly associated with various biomarker levels. Female sex was positively associated with BMP10 and FGF23 (atrial fibrosis), but negatively associated with hsTNT (cardiac injury). Conclusion In patients with AF scheduled for catheter ablation, we identified several clinical determinants of biomarker levels with potential implications for disease mechanisms. In women, pro-fibrotic biomarkers were frequently higher, while male patients more often showed signs of myocardial injury. Importantly, rhythm during blood draw is a very strong determinant of many biomarkers and should be taken into account in future biomarker studies.Figure 1.Table 1.

#2743 Impact of fatty acid-binding protein 4 on SUMOylation balance and renal tubular epithelial cell senescence in acute kidney injury

Abstract Background and Aims Dysregulated lipid metabolism and cellular senescence intricately interact in the context of acute kidney injury (AKI). Fatty acid-binding protein 4 (FABP4), a critical enzyme regulating lipid metabolism, potentially induces cell senescence through lipotoxicity in AKI. However, the specific mechanisms remain unclear. Method We established an ischemia-reperfusion-induced AKI (IRI-AKI) model in C57 mice and quantified and localized FABP4 expression in renal tissues using Western blotting (WB), qPCR, and immunofluorescence (IF). Oil Red O staining and beta-galactosidase staining were employed to assess lipid deposition and cellular senescence in tubular cells. The same measurements were repeated in IRI-AKI by knocking out Fabp4. Additionally, bulk mRNA sequencing and single-cell sequencing were conducted on renal tissues to analyze key molecules and related mechanisms. Results In vivo, we observed a significant decline in renal function, severe tubular epithelial damage, and abundant inflammation in the IRI-AKI group, which was noticeably alleviated in the Fabp4 knockout group (Fig. 1). Furthermore, we detected upregulation of FABP4 expression in the kidneys of IRI-AKI, primarily localized in the tubular epithelial cells. Fabp4 knockout effectively reduced tubular lipid accumulation and cellular senescence (Fig. 3). Through integrating mRNA and single-cell sequencing data, UBC9, an E2 enzyme involved in protein SUMOylation, emerged as a potential key regulator of cell senescence and AKI. WB and qPCR both confirmed the upregulation of UBC9 expression in IRI-AKI and its downregulation after Fabp4 knockout. Conversely, we observed that downregulated SUMOylation in IRI-AKI was upregulated in the Fabp4 knockout group (Fig. 4). Conclusion In conclusion, FABP4 modulates the expression of UBC9 and SUMOylation, thereby mediating cellular senescence and causing renal tubular cell damage in IRI-AKI. The mechanisms underlying FABP4’s regulation of UBC9 and the opposing trend between UBC9 and SUMOylation require further elucidation.

#412 Influence of SGLT2I on tubulointerstitium in DKD patients with moderate renal dysfunction

Abstract Background and Aims In the FAGOTTO study (jRCTs041200069) to evaluate changes of renal hemodynamics on initial glomerular filtration rate (GFR) dip induced by Sodium-glucose cotransporter 2 inhibitors (SGLT2i) in patients (pts) with type 2 diabetic kidney disease (DKD) and moderate renal dysfunction, we reported that SGLT2 inhibition maintained the levels of glomerular filtration fraction (FF) and renal vascular resistance (RVR) during decrease in GFR as well as renal plasma and blood flow. In this sub analysis, we evaluated if GFR dip by SGLT2i might induce tubulointerstitial disorder by measuring urinary biomarkers. Method The FAGOTTO study was a 12-week multicenter, open-label, randomized (1:1), parallel-group study treated with Canagliflozin (Group CA) or control groups (Group CO) in DKD pts with 30 ≤ estimated GFR (eGFR) ≤ 60 mL/min/1.73 m2. Urinary biomarkers including liver-type fatty-acid binding protein (L-FABP), N-acetyl-glucosaminidase (NAG), β2-microglobulin (β2MG) and monocyte chemoattractant protein-1 (MCP-1) were measured at baseline, 4 weeks and 12 weeks after start of the trial. The adjusted mean and SE for changes were calculated at each time point by a linear mixed model with baseline values, time point, and interaction of the treatment group as the fixed effects. We compared these changes between treatment the groups the Tukey-Kramer method to correct for multiplicity. Results The adjusted mean changes in L-FABP at the 4-week and 12-week time point after trial start were estimated −0.35 and −0.17 μg/gCr in Group CA and 0.06 and 1.23 μg/gCr in Group CO in a linear mixed model, respectively. Similarly, the changes were estimated 2.63 and 3.71 U/gCr in Group CA and 1.38 and −1.21 U/gCr in Group CO in NAG, 317.7 and 291.4 μg/gCr in Group CA and 416.6 and 375.1 μg/gCr in Group CO in β2MG and 19.6 and 64.6 pg/gCr in Group CA and −7.7 and −2.7 pg/gCr in Group CO in MCP-1, respectively. When compared the changes in L-FABP, NAG, β2MG and MCP-1 between Group Ca and Group Co by Tukey-Kramer multiple-comparison test, there were no significant differences in any biomarkers. (Figure). Conclusion In this analysis, no significant difference in any of these biomarkers was detected in Group CA compared to those in Group CO at 4 weeks and 12 weeks after administration of SGLT2i. Although further studies should be needed to conclude, transient decrease in GFR after administration of SGLT2i might not be involved with tubulointerstitial damage and our study gives one evidence as a safety information in use of SGLT2i to DKD pts with moderate renal dysfunction.

Metabolic profiling of galectin-1 and galectin-3: a cross-sectional, multi-omics, association study.

Experimental studies indicate a role for galectin-1 and galectin-3 in metabolic disease, but clinical evidence from larger populations is limited. We measured circulating levels of galectin-1 and galectin-3 in the Prospective investigation of Obesity, Energy and Metabolism (POEM) study, participants (n = 502, all aged 50 years) and characterized the individual association profiles with metabolic markers, including clinical measures, metabolomics, adipose tissue distribution (Imiomics) and proteomics. Galectin-1 and galectin-3 were associated with fatty acids, lipoproteins and triglycerides including lipid measurements in the metabolomics analysis adjusted for body mass index (BMI). Galectin-1 was associated with several measurements of adiposity, insulin secretion and insulin sensitivity, while galectin-3 was associated with triglyceride-glucose index (TyG) and fasting insulin levels. Both galectins were associated with inflammatory pathways and fatty acid binding protein (FABP)4 and -5-regulated triglyceride metabolic pathways. Galectin-1 was also associated with several proteins related to adipose tissue differentiation. The association profiles for galectin-1 and galectin-3 indicate overlapping metabolic effects in humans, while the distinctly different associations seen with fat mass, fat distribution, and adipose tissue differentiation markers may suggest a functional role of galectin-1 in obesity.

Adipocytes and metabolism: Contributions to multiple myeloma

Obesity contributes to many cancers, including breast cancer and multiple myeloma, two cancers that often colonize the bone marrow (BM). Obesity often causes metabolic disease, but at the cellular level, there is uncertainty regarding how these shifts affect cellular phenotypes. Evidence is building that different types of fuel affect tumor cell metabolism, mitochondrial function, and signaling pathways differently, but tumor cells are also flexible and adapt to less-than ideal metabolic conditions, suggesting that single-pronged attacks on tumor metabolism may not be efficacious enough to be effective clinically. In this review, we describe the newest research at the pre-clinical level on how tumor metabolic pathways and energy sources affect cancer cells, with a special focus on multiple myeloma (MM). We also describe the known forward-feedback loops between bone marrow adipocytes (BMAds) and local tumor cells that support tumor growth. We describe how metabolic targets and transcription factors related to fatty acid (FA) oxidation, FA biosynthesis, glycolysis, oxidative phosphorylation (OXPHOS), and other pathways hold great promise as new vulnerabilities in myeloma cells. Specifically, we describe the importance of the acetyl-CoA synthetase (ACSS) and the acyl-CoA synthetase long chain (ACSL) families, which are both involved in FA metabolism. We also describe new data on the importance of lactate metabolism and lactate transporters in supporting the growth of tumor cells in a hypoxic BM microenvironment. We highlight new data showing the dependency of myeloma cells on the mitochondrial pyruvate carrier (MPC), which transports pyruvate to the mitochondria to fuel the tricarboxylic acid (TCA) cycle and electron transport chain (ETC), boosting OXPHOS. Inhibiting the MPC affects myeloma cell mitochondrial metabolism and growth, and synergizes with proteosome inhibitors in killing myeloma cells. We also describe how metabolic signaling pathways intersect established survival and proliferation pathways; for example, the fatty acid binding proteins (FABPs) affect MYC signaling and support growth, survival, and metabolism of myeloma cells. Our goal is to review the current the field so that novel, metabolic-focused therapeutic interventions and treatments can be imagined, developed and tested to decrease the burden of MM and related cancers.

Maternal supplementation with n-3 fatty acids affects placental lipid metabolism, inflammation, oxidative stress, the endocannabinoid system, and the neonate cytokine concentrations in dairy cows

BackgroundThe placenta plays a crucial role in supporting and influencing fetal development. We compared the effects of prepartum supplementation with omega-3 (n-3) fatty acid (FA) sources, flaxseed oil (FLX) and fish oil (FO), on the expression of genes and proteins related to lipid metabolism, inflammation, oxidative stress, and the endocannabinoid system (ECS) in the expelled placenta, as well as on FA profile and inflammatory response of neonates. Late-pregnant Holstein dairy cows were supplemented with saturated fat (CTL), FLX, or FO. Placental cotyledons (n = 5) were collected immediately after expulsion, and extracted RNA and proteins were analyzed by RT-PCR and proteomic analysis. Neonatal blood was assessed for FA composition and concentrations of inflammatory markers.ResultsFO increased the gene expression of fatty acid binding protein 4 (FABP4), interleukin 10 (IL-10), catalase (CAT), cannabinoid receptor 1 (CNR1), and cannabinoid receptor 2 (CNR2) compared with CTL placenta. Gene expression of ECS-enzyme FA-amide hydrolase (FAAH) was lower in FLX and FO than in CTL. Proteomic analysis identified 3,974 proteins; of these, 51–59 were differentially abundant between treatments (P ≤ 0.05, |fold change| ≥ 1.5). Top canonical pathways enriched in FLX vs. CTL and in FO vs. CTL were triglyceride metabolism and inflammatory processes. Both n-3 FA increased the placental abundance of FA binding proteins (FABPs) 3 and 7. The abundance of CNR1 cannabinoid-receptor-interacting-protein-1 (CNRIP1) was reduced in FO vs. FLX. In silico modeling affirmed that bovine FABPs bind to endocannabinoids. The FLX increased the abundance of inflammatory CD44-antigen and secreted-phosphoprotein-1, whereas prostaglandin-endoperoxide synthase 2 was decreased in FO vs. CTL placenta. Maternal FO enriched neonatal plasma with n-3 FAs, and both FLX and FO reduced interleukin-6 concentrations compared with CTL.ConclusionMaternal n-3 FA from FLX and FO differentially affected the bovine placenta; both enhanced lipid metabolism and modulated oxidative stress, however, FO increased some transcriptional ECS components, possibly related to the increased FABPs. Maternal FO induced a unique balance of pro- and anti-inflammatory components in the placenta. Taken together, different sources of n-3 FA during late pregnancy enhanced placental immune and metabolic processes, which may affect the neonatal immune system.

Neutrophil lymphocyte ratio and heart type fatty acid binding protein as a prognostic marker in Myocardial infarction within 48h of admission.

The neutrophil to lymphocyte ratio (NLR) is a measure of systemic inflammation, whereas Heart type fatty acid protein (HFABP) is a cytosolic protein released early after acute coronary syndrome (ACS). The aim of this research study is to determine whether NLR and H-FAB are useful in predicting the prognosis in patients with ST segment elevation myocardial infarction (STEMI) 48h after admission. This is a prospective observational study conducted on 97 patients who had been admitted to emergency room with ST-elevation myocardial infarction in their ECG in a tertiary care centre of south India. The neutrophil-lymphocyte ratio was measured at the time of admission, 24th hour and 48th hour, and then compared with the outcome. To determine their significance in the MI episode, troponin-I and H-FABP were also measured. A significant correlation was found in the final outcomes of patients and the NLR at the time of admission and at 48h (p = 0.01). Additionally, a substantial correlation between NLR and various degrees of LV dysfunction was also observed (p = 0.01). H-FABP was found to be positive in all 97 of the patients examined, whereas Troponin-I was only found to be positive in 56.7%. The study's findings, indicated strong correlations between NLR and LVEF, indicated that NLR might serve as an early predictor of cardiac events which could be either poor prognosis or higher mortality. This research found that H-FABP may serve as an early MI diagnostic marker.

Markers of enterocyte damage, microbial translocation and systemic inflammation following 9 hours of heat exposure in young and older adults.

Heat stress induced damage to the gastrointestinal barrier can induce local and systemic inflammatory reactions implicated in heat-stroke. Gastrointestinal barrier damage has been shown to be greater in older relative to young adults following hyperthermia. However, comparisons between young and older adults have been limited to brief exposures (3-h), which may not reflect the duration of heat stress experienced during heat waves. We therefore evaluated markers of intestinal epithelial damage (Log transformed intestinal fatty acid binding protein, IFABPLOG), microbial translocation (soluble cluster of differentiation 14, sCD14LOG), and systemic inflammation (tumour necrosis factor alpha, TNF-αLOG; interleukin 6, IL-6LOG; C-reactive protein, CRP) in 19 young (interquartile range: 21-27 yr; 10 females) and 37 older (68-73 yr; 10 females) adults before and after 9-h of rest in 40°C (9% relative humidity). The magnitude of the increase in IFABPLOG was 0.38 log pg/mL (95% CI, 0.10, 0.65 log pg/mL) greater in the older relative to young cohort (P=0.049) after 9-h heat exposure. At baseline both IL-6LOG and CRP concentrations were higher in the older (IL-6: 2.67 (1.5) log pg/mL, CRP: 0.28 (1.5) mg/mL) relative to the young (IL-6: 1.59 log pg/mL, SD 1.2; CRP: 0.11 mg/mL, SD 1.7) group (both P<0.001). The change in IL-6 and CRP was similar between groups following 9-h heat exposure (IL-6: P=0.053; CRP: P=0.24). Neither sCD14LOG and TNF-αLOG were different between groups at baseline nor altered after 9-h heat exposure. Our data indicate that age may modify intestinal epithelial injury following 9 h of passive heat exposure.

Fatty acid binding to the human transport proteins FABP3, FABP4, and FABP5 from a Ligand’s perspective

Fatty acid binding proteins (FABPs) are a family of amphiphilic transport proteins with high diversity in terms of their amino acid sequences and binding preferences. Beyond their main biological role as cytosolic fatty acid transporters, many aspects regarding their binding mechanism and functional specializations in human cells remain unclear. In this work, the binding properties and thermodynamics of FABP3, FABP4 and FABP5 were analyzed under various physical conditions. For this purpose, the FABPs were loaded with fatty acids bearing fluorescence or spin probes as model ligands, comparing their binding affinities via microscale thermophoresis (MST) and continuous-wave electron paramagnetic resonance (CW EPR) spectroscopy. The CW EPR spectra of non-covalently bound 5- and 16-DOXYL stearic acid (5/16-DSA) deliver in-depth information about the dynamics and chemical environments of ligands inside the binding pockets of the FABPs. EPR spectral simulations allow the construction of binding curves, revealing two different binding states (‘intermediately’ and ‘strongly’ bound). The proportion of bound 5/16-DSA depends strongly on the FABP concentration and the temperature, but with remarkable differences between the three isoforms. Additionally, the more dynamic state (‘intermediately bound’) seems to dominate at body temperature with thermodynamic preference. The ligand binding studies were supplemented by aggregation studies via dynamic light scattering (DLS) and bioinformatic analyses. Beyond the remarkably fine-tuned binding properties exhibited by each FABP, which were discernible with our EPR-centered approach, the results of this work attest the power of simple spectroscopic experiments to provide new insights into the ligand binding mechanisms of proteins in general on a molecular level.

Concentration of fatty acid binding protein as a new indicator of ejaculate fertility

Objective. To determine the marker function of fatty acid binding protein (FABP) concentration in seminal plasma (SP) in order to assess ejaculate fertility used in in vitro fertilization (IVF) treatment of infertility in couples. Materials and methods. The study involved semen samples of 96 men of reproductive age: the study group (n=63) – patients with a decrease in concentration and/or total content of spermatozoa in ejaculate, the comparison group (n=33) – men with normal concentration and number of spermatozoa in ejaculate. The content of FABP in SP was determined by enzyme-linked immunosorbent assay using the test system “FABP – ELISA – BEST” (A-9102, Vector-Best, Russia). In order to determine the informative value of using the concentration of FABP in SP as a criterion of ejaculate fertility of men of the study group, the predictive value of positive and negative IVF results was determined by calculating the diagnostic sensitivity, specificity and efficiency. Results. The content of FABP in SP accounted for 1.29 ± 0.24 ng/mL, the median and interquartile range comprised 1.23 [1.13–1.35] ng/mL, ranging from 1.08 to 2.79 ng/mL. The study revealed statistically significant intergroup differences (Mann-Whitney test U=79.00; p=0.000016), a weak correlation between the level of FABP and the concentration of spermatozoa (R=0.578008) and their number in ejaculate (R=0.583599). The diagnostic sensitivity of the test for FABP in SP of the men of the study group accounted for 81.82%, specificity – 78.95%, efficiency – 80.95%. Conclusion. Seminal plasma FABP can act as a marker of spermatogenesis disorders. The study of this protein in ejaculate provides the accuracy of predicting the outcome of in vitro fertilization.

A novel method for multiple cardiovascular disease biomarker detection using a SERF-based microfluidic platform

As cardiovascular diseases (CVDs) are the leading cause of death worldwide, it is of great importance to realize a rapid and sensitive diagnosis. Multiple CVD biomarker detection, which holds higher accuracy and speed of early CVD diagnosis, is becoming a promising alternative to single biomarker analysis. Cardiac troponin I (cTnI), C-reactive protein (CRP), brain-type natriuretic peptide (BNP), and heart fatty acid binding protein (H-FABP) are four significant diagnostic biomarkers for CVDs. Among the several methods for biomarker detection, such as optical, magnetic, mechanical, and electrical methods, the magnetic method stands out because of its stability, low toxicity, noninvasive detection, facile manipulation with an external magnetic field, and immunity to the interference of background light. At present, the lack of multiplexing capability, the imprecision of magnetic signal localization, and the agglomeration and non-specific adsorption of magnetic nanoparticles all limit the clinical application of magnetic detection. This paper presented a novel method for multiple CVD biomarker detection using a spin exchange relaxation-free (SERF)-based microfluidic platform. One or more SERF atomic magnetometers were used to scan the remanent field of magnetic labels to detect four CVD biomarkers in 70 min, with a detection limit of 1.88 pg/mL (cTnI), 1.58 pg/mL (CRP), 1.45 pg/mL (BNP), and 1.71 pg/mL (H-FABP). The results showed two-dimensional magnetic fields with a resolution of submillimeter level and a sensitivity of pT level. The measurement technique provides a new magnetic methodology for applications in clinical diagnosis.