OBJECTIVE: To investigate the changes in myocardial calcium currents in rats subjected to forced running exercise during acute hypoxia and their association with myocardial injury. METHODS: Forty SD rats were randomized into quiescent group and running group either in normal oxygen (NQ and NR groups, respectively) or in acute hypoxia (HQ and HR groups, respectively). Hypoxia was induced by keeping the rats in a hypobaric oxygen chamber (PaO₂=61.6kpa) for 4 h a day; the rats in the two running groups were forced to run on running wheels for 4 h each day. Rat ventricular myocytes was isolated by enzymatic digestion for recording action potentials and currents using patch clamp technique, and confocal Ca²⁺ imaging was used to monitor intracellular Ca²⁺ levels. The expressions of Cav1.2 channel and the cardiac ryanodine receptor (RyR2) were determined using Western blotting. RESULTS: Compared with those in NQ group, the rats in HR group showed significantly decreased SOD activity (P < 0.01), increased h-FABP, hs-CRP and IMA levels (P < 0.05 or 0.01), obvious myocardial pathology, and prolonged APD50 and APD90 (P < 0.05). Of the different stress conditions, forced running in acute hypoxia resulted in the most prominent increase of the densities of ICa, L currents, causing also a significant left shift of the steady state activation curve and a significant right shift of the steady state inactivation curve. Compared with those in NQ group, the rats in NR, HQ and HR groups all exhibited higher rates of spontaneous calcium wave events in the cardiac myocytes, increased frequency of calcium sparks with lowered amplitude, enhanced calcium release amplitude in the ventricular myocytes, and delayed calcium ion reabsorption; in particular, these changes were the most conspicuous in HR group (P < 0.05 or 0.01). There was also a significant increase in the protein levels of Cav1.2 channel and RyR2 receptor in HR group (P < 0.05 or 0.01). CONCLUSIONS The mechanism of myocardial injury in rats subjected to forced running in acute hypoxia may involve the increase of oxidative stress and calcium current and intracellular calcium overload.
Animals ; C-Reactive Protein/metabolism* ; Calcium/metabolism* ; Calcium Signaling ; Fatty Acid Binding Protein 3/metabolism* ; Heart Injuries/metabolism* ; Hypoxia/metabolism* ; Myocytes, Cardiac/metabolism* ; Oxygen/metabolism* ; Rats ; Rats, Sprague-Dawley ; Ryanodine Receptor Calcium Release Channel/metabolism* ; Superoxide Dismutase/metabolism*

Objective To observe the skin ultrastructure change of electric shock death rats and to test the expression changes of hypoxia-inducible factor-2α （HIF-2α） and heart type-fatty acid-binding protein （H-FABP） of myocardial cells, in order to provide basis for forensic identification of electric shock death. Methods The electric shock model of rats was established. The 72 rats were randomly divided into control group, electric shock death group and postmortem electric shock group. Each group was divided into three subgroups, immediate （0 min）, 30 min and 60 min after death. The skin changes of rats were observed by HE staining, the changes of skin ultrastructure were observed by scanning electron microscopy, and the expression of HIF-2α and H-FABP in rats myocardium was tested by immunohistochemical staining. Results The skin in the electric shock death group and postmortem electric shock group had no significant difference through the naked eye or by HE staining. Under the scanning electron microscope, a large number of cellular debris, cells with unclear boundaries, withered cracks, circular or elliptical holes scattered on the cell surface and irregular edges were observed. A large number of spherical foreign body particles were observed. Compared with the control group, the expression of HIF-2α in all electric shock death subgroups increased, reaching the peak immediately after death. In the postmortem electric shock group, HIF-2α expression only increased immediately after death, but was lower than that of electric shock death group （P<0.05）. Compared with the control group, the expression of H-FABP in all subgroups of electric shock death group and postmortem electric shock group significantly decreased. The expression of H-FABP in all subgroups of electric shock death group was lower than that of the postmortem electric shock group （P<0.05）. Conclusion Electric shock can increase HIF-2α expression and decrease H-FABP expression in the myocardium, which may be of forensic significance for the determination of electric shock death and identification of antemortem and postmortem electric shock.
Animals ; Autopsy ; Basic Helix-Loop-Helix Transcription Factors/metabolism* ; Fatty Acid Binding Protein 3/metabolism* ; Myocardium/metabolism* ; Myocytes, Cardiac/metabolism* ; Rats ; Skin/ultrastructure*

OBJECTIVE: To observe the protective effect of heart-fatty acid binding protein (H-FABP) on lipopolysaccharide (LPS)-induced cardiomyocyte damage. METHODS: The cardiomyocytes were isolated and cultured from 1-3 days old neonatal rats. The specific siRNA or plasmid of H-FABP were transfected into cells to alter H-FABP expression, which was evaluated by Western blot and quantitative-PCR. LPS-induced cardiomyocyte damage and inflammation were estimated by detecting the contents of lactate dehydrogenase(LDH), TNF-α, and IL-1β as well as cell viability. RESULTS: LPS treatment induced inflammation and cell damage indicated by a decrease in cell viability and an increase in LDH, TNF-α and IL-1β in the medium. When H-FABP was downregulated by siRNA transfection, the LPS-induced inflammation and cell damage were augmented. In contrast, when H-FABP was overexpressed by pcDNA3.1-H-FABP transfection, the LPS-induced inflammation and cell damage were suppressed. CONCLUSION H-FABP protects cardiomyocytes from LPS-induced inflammation and cell injury.
Animals ; Animals, Newborn ; Cell Line ; Cell Survival ; Down-Regulation ; Fatty Acid Binding Protein 3 ; Fatty Acid-Binding Proteins ; metabolism ; Inflammation ; metabolism ; Interleukin-1beta ; metabolism ; L-Lactate Dehydrogenase ; metabolism ; Lipopolysaccharides ; adverse effects ; Myocytes, Cardiac ; cytology ; drug effects ; RNA, Small Interfering ; genetics ; Rats ; Transfection ; Tumor Necrosis Factor-alpha ; metabolism

Serum palmitic acid (PA), a type of saturated fatty acid, causes lipid accumulation and induces toxicity in hepatocytes. Ethanol (EtOH) is metabolized by the liver and induces hepatic injury and inflammation. Herein, we analyzed the effects of EtOH on PA-induced lipotoxicity in the liver. Our results indicated that EtOH aggravated PA-induced apoptosis and lipid accumulation in primary rat hepatocytes in dose-dependent manner. EtOH intensified PA-caused endoplasmic reticulum (ER) stress response in vitro and in vivo, and the expressions of CHOP, ATF4, and XBP-1 in nucleus were significantly increased. EtOH also increased PA-caused cleaved caspase-3 in cytoplasm. In wild type and CHOP(-/-) mice treated with EtOH and high fat diet (HFD), EtOH worsened the HFD-induced liver injury and dyslipidemia, while CHOP knockout blocked toxic effects of EtOH and PA. Our study suggested that targeting UPR-signaling pathways is a promising, novel approach to reducing EtOH and saturated fatty acid-induced metabolic complications.
Activating Transcription Factor 4 ; drug effects ; metabolism ; Animals ; Apoptosis ; drug effects ; Caspase 3 ; drug effects ; Chemical and Drug Induced Liver Injury ; metabolism ; DNA-Binding Proteins ; drug effects ; metabolism ; Diet, High-Fat ; adverse effects ; Dose-Response Relationship, Drug ; Dyslipidemias ; chemically induced ; metabolism ; Endoplasmic Reticulum Stress ; drug effects ; Ethanol ; metabolism ; toxicity ; Fatty Liver ; chemically induced ; metabolism ; Gene Knockout Techniques ; Hepatocytes ; drug effects ; metabolism ; Lipid Metabolism ; drug effects ; Liver ; metabolism ; Male ; Mice ; Palmitic Acid ; toxicity ; Rats ; Rats, Sprague-Dawley ; Regulatory Factor X Transcription Factors ; Signal Transduction ; drug effects ; Transcription Factor CHOP ; drug effects ; genetics ; metabolism ; Transcription Factors ; drug effects ; metabolism ; Unfolded Protein Response ; drug effects ; X-Box Binding Protein 1

OBJECTIVETo evaluation the performance of a heart-type fatty acid-binding protein (H-FABP) ELISA detection kit in the clinical diagnosis of acute coronary syndrome (ACS).

METHODSPlasma or serum samples from 160 suspected ACS patients hospitalized in General Hospital of PLA were examined using Lanzhou H-FABP reagent kit and Holland H-FABP kit. Correlation of the two kits was evaluated and Kappa test was used to examine the consistency of the results of the two products.

RESULTSThe sensitivity of H-FABP diagnosis of ACS detection Lanzhou kit was 91.8%, the specificity was 88.7%, and the total diagnostic rate was 90.42%. The sensitivity of H-FABP diagnosis of ACS detection Holland kit was 90.3%, the specificity was 86.8%, and the total diagnostic rate was 88.75%. The test results showed that two products yielded comparable results (P=0.668, >0.05) with a good consistency (Kappa=0.726, P<0.01).

CONCLUSIONSH-FABP ELISA detection kit produccted by LanZhou biological research institute has a good correlation with H-FABP detection kit produced by HBT company of Holland and has the potential for clinical application.

Acute Coronary Syndrome ; diagnosis ; Biomarkers ; blood ; Enzyme-Linked Immunosorbent Assay ; Fatty Acid Binding Protein 3 ; Fatty Acid-Binding Proteins ; blood ; Humans ; Reagent Kits, Diagnostic ; Reproducibility of Results ; Sensitivity and Specificity

OBJECTIVETo study the value of the biochemical markers heart fatty acid binding protein (H-FABP), creatine kinase isoenzyme-MB (CK-MB), myocardial troponin T (cTnT) in early diagnosis of acute myocardial infarction (AMI).

METHODSSerum levels of H-FABP, CK-MB, and cTNT were detected in 95 patients with confirmed AMI at different time points following the onset in comparison with the data from 43 patients without AMI. The sensitivity and specificity of H-FABP in different phases following the onset were compared between those of CK-MB and cTnT.

RESULTSSerum H-FABP activities increased significantly within 3 h after the onset of AMI (P<0.01) and continued to increase at 3-6 h and 6-12 h (P<0.001). Serum level of CK-MB within 6 h and cTnT level within 3 h after AMI onset did not show obvious changes (P<0.05). Both the diagnostic sensitivity and specificity of H-FABP within 3 h and within 3-6 h were higher than those CK-MB and cTnT (P<0.05).

CONCLUSIONH-FABP is superior to CK-MB and cTnT in early diagnosis (within 3 h and 3-6 h following the onset) of AMI.

Acute Disease ; Biomarkers ; blood ; Creatine Kinase, MB Form ; blood ; Early Diagnosis ; Fatty Acid Binding Protein 3 ; Fatty Acid-Binding Proteins ; blood ; Humans ; Myocardial Infarction ; diagnosis ; Sensitivity and Specificity ; Troponin T ; blood

Escherichia coli (E. coli) FadR regulator plays dual roles in fatty acid metabolism, which not only represses the fatty acid degradation (fad) system, but also activates the unsaturated fatty acid synthesis pathway. Earlier structural and biochemical studies of FadR protein have provided insights into interplay between FadR protein with its DNA target and/or ligand, while the missing knowledge gap (esp. residues with indirect roles in DNA binding) remains unclear. Here we report this case through deep mapping of old E. coli fadR mutants accumulated. Molecular dissection of E. coli K113 strain, a fadR mutant that can grow on decanoic acid (C10) as sole carbon sources unexpectedly revealed a single point mutation of T178G in fadR locus (W60G in FadRk113). We also observed that a single genetically-recessive mutation of W60G in FadR regulatory protein can lead to loss of its DNA-binding activity, and thereby impair all the regulatory roles in fatty acid metabolisms. Structural analyses of FadR protein indicated that the hydrophobic interaction amongst the three amino acids (W60, F74 and W75) is critical for its DNA-binding ability by maintaining the configuration of its neighboring two β-sheets. Further site-directed mutagenesis analyses demonstrated that the FadR mutants (F74G and/or W75G) do not exhibit the detected DNA-binding activity, validating above structural reasoning.
3-Oxoacyl-(Acyl-Carrier-Protein) Synthase ; genetics ; metabolism ; Amino Acid Sequence ; Bacterial Proteins ; chemistry ; genetics ; metabolism ; DNA, Bacterial ; chemistry ; metabolism ; Escherichia coli ; genetics ; metabolism ; Escherichia coli Proteins ; genetics ; metabolism ; Fatty Acid Synthase, Type II ; genetics ; metabolism ; Fatty Acids ; metabolism ; Gene Expression Regulation, Bacterial ; Hydro-Lyases ; genetics ; metabolism ; Hydrophobic and Hydrophilic Interactions ; Lipid Metabolism ; Models, Molecular ; Molecular Sequence Data ; Mutation ; Protein Binding ; Protein Structure, Secondary ; Repressor Proteins ; chemistry ; genetics ; metabolism ; Sequence Alignment ; Sequence Homology, Amino Acid ; Signal Transduction

BACKGROUND: Enhanced lipogenesis plays a critical role in cell senescence via induction of expression of the mature form of sterol regulatory element binding protein 1 (SREBP1), which contributes to an increase in organellar mass, one of the indicators of senescence. We investigated the molecular mechanisms by which signaling molecules control SREBP1-mediated lipogenesis and senescence. METHODS: We developed cellular models for stress-induced senescence, by exposing Chang cells, which are immortalized human liver cells, to subcytotoxic concentrations (200 microM) of deferoxamine (DFO) and H2O2. RESULTS: In this model of stress-induced cell senescence using DFO and H2O2, the phosphorylation profile of glycogen synthase kinase 3alpha (GSK3alpha) and beta corresponded closely to the expression profile of the mature form of SREBP-1 protein. Inhibition of GSK3 with a subcytotoxic concentration of the selective GSK3 inhibitor SB415286 significantly increased mature SREBP1 expression, as well as lipogenesis and organellar mass. In addition, GSK3 inhibition was sufficient to induce senescence in Chang cells. Suppression of GSK3 expression with siRNAs specific to GSK3alpha and beta also increased mature SREBP1 expression and induced senescence. Finally, blocking lipogenesis with fatty acid synthase inhibitors (cerulenin and C75) and siRNA-mediated silencing of SREBP1 and ATP citrate lyase (ACL) significantly attenuated GSK3 inhibition-induced senescence. CONCLUSION: GSK3 inactivation is an important upstream event that induces SREBP1-mediated lipogenesis and consequent cell senescence.
Aging* ; Aminophenols ; ATP Citrate (pro-S)-Lyase ; Carrier Proteins* ; Cell Aging ; Deferoxamine ; Fatty Acid Synthetase Complex ; Glycogen Synthase Kinase 3* ; Glycogen Synthase Kinases* ; Glycogen Synthase* ; Glycogen* ; Humans ; Lipogenesis* ; Liver ; Maleimides ; Multienzyme Complexes ; Oxo-Acid-Lyases ; Phosphorylation ; RNA, Small Interfering ; Sterol Regulatory Element Binding Protein 1

BACKGROUND: Enhanced lipogenesis plays a critical role in cell senescence via induction of expression of the mature form of sterol regulatory element binding protein 1 (SREBP1), which contributes to an increase in organellar mass, one of the indicators of senescence. We investigated the molecular mechanisms by which signaling molecules control SREBP1-mediated lipogenesis and senescence. METHODS: We developed cellular models for stress-induced senescence, by exposing Chang cells, which are immortalized human liver cells, to subcytotoxic concentrations (200 microM) of deferoxamine (DFO) and H2O2. RESULTS: In this model of stress-induced cell senescence using DFO and H2O2, the phosphorylation profile of glycogen synthase kinase 3alpha (GSK3alpha) and beta corresponded closely to the expression profile of the mature form of SREBP-1 protein. Inhibition of GSK3 with a subcytotoxic concentration of the selective GSK3 inhibitor SB415286 significantly increased mature SREBP1 expression, as well as lipogenesis and organellar mass. In addition, GSK3 inhibition was sufficient to induce senescence in Chang cells. Suppression of GSK3 expression with siRNAs specific to GSK3alpha and beta also increased mature SREBP1 expression and induced senescence. Finally, blocking lipogenesis with fatty acid synthase inhibitors (cerulenin and C75) and siRNA-mediated silencing of SREBP1 and ATP citrate lyase (ACL) significantly attenuated GSK3 inhibition-induced senescence. CONCLUSION: GSK3 inactivation is an important upstream event that induces SREBP1-mediated lipogenesis and consequent cell senescence.
Aging* ; Aminophenols ; ATP Citrate (pro-S)-Lyase ; Carrier Proteins* ; Cell Aging ; Deferoxamine ; Fatty Acid Synthetase Complex ; Glycogen Synthase Kinase 3* ; Glycogen Synthase Kinases* ; Glycogen Synthase* ; Glycogen* ; Humans ; Lipogenesis* ; Liver ; Maleimides ; Multienzyme Complexes ; Oxo-Acid-Lyases ; Phosphorylation ; RNA, Small Interfering ; Sterol Regulatory Element Binding Protein 1

OBJECTIVETo study serum levels of heart-type fatty acid-binding protein (h-FABP) in children with chronic heart failure (CHF), and the correlation between heart function and the level of h-FABP, with the aim of studying the significance of h-FABP in CHF.

METHODSThirty-six children with CHF, including 16 cases of endocardial fibroelastosis (EFE) and 20 cases of dilated cardiomyopathy (DCM) were enrolled in the study. Thirty healthy children sevred as the control group. Serum levels of h-FABP were determined using ELISA, and left ventricular ejection fraction (LVEF), cardiac index (CI) and fractional shortening of the left ventricle (LVSF) were measured by two-dimensional echocardiography in the CHF group.

RESULTSMean levels of h-FABP in the CHF group were significantly higher than in the control group (21.7±4.3 ng/mL vs 6.2±1.7 ng/mL; P<0.01). The worse the heart function, the higher the h-FABP levels (P<0.01). Mean levels of h-FABP in both the EFE and DCM groups were significantly higher than in the control group (P<0.01). Serum h-FABP concentrations were negatively correlated with LVEF, CI and LVSF (r=-0.65, -0.64 and -0.71 respectively; P<0.01) in the CHF group.

CONCLUSIONSSerum h-FABP levels increase in children with CHF and are closely related to the severity of the condition. Serum h-FABP levels can be used as a biomarker for the diagnosis of heart failure and the evaluation of its severity.

Cardiomyopathy, Dilated ; blood ; Child ; Child, Preschool ; Chronic Disease ; Endocardial Fibroelastosis ; blood ; Fatty Acid Binding Protein 3 ; Fatty Acid-Binding Proteins ; blood ; Female ; Heart Failure ; blood ; physiopathology ; Humans ; Infant ; Male ; Severity of Illness Index