Challenges and support needs in psychological and physical health among pilots: a qualitative study.

Introduction: Physical and mental health problems among pilots affect their working state and impact flight safety. Although pilots' physical and mental health problems have become increasingly prominent, their health has not been taken seriously. This study aimed to clarify challenges and support needs related to psychological and physical health among pilots to inform development of a more scientific and comprehensive physical and mental health system for civil aviation pilots. Methods: This qualitative study recruited pilots from nine civil aviation companies. Focus group interviews via an online conference platform were conducted in August 2022. Colaizzi analysis was used to derive themes from the data and explore pilots' experiences, challenges, and support needs. Results: The main sub-themes capturing pilots' psychological and physical health challenges were: (1) imbalance between family life and work; (2) pressure from assessment and physical examination eligibility requirements; (3) pressure from worries about being infected with COVID-19; (4) nutrition deficiency during working hours; (5) changes in eating habits because of the COVID-19 pandemic; (6) sleep deprivation; (7) occupational diseases; (8) lack of support from the company in coping with stress; (9) pilots' yearly examination standards; (10) support with sports equipment; (11) respecting planned rest time; and (12) isolation periods. Discussion: The interviewed pilots experienced major psychological pressure from various sources, and their physical health condition was concerning. We offer several suggestions that could be addressed to improve pilots' physical and mental health. However, more research is needed to compare standard health measures for pilots around the world in order to improve their physical and mental health and contribute to overall aviation safety.

Salvianolic Acid B Ameliorated Chemotherapeutic Injury of Cardiac Myocytes through the Nrf2/ARE Signaling Pathway.

BACKGROUND: Cardiotoxicity has been corroborated to be the toxic influence of cisplatin (CDDP). Oxidative stress and cardiomyocyte apoptosis play a vital part in cardiotoxicity induced by CDDP. Salvianolic acid Salvianolic acid B (SalB) is a monomeric component of Salvia miltiorrhiza, which has antioxidant and anti-inflammatory influences. In this research, we explored the mechanism of SalB in cardiotoxicity induced by CDDP. METHOD: 36 Wistar rats were separated into sham subgroup, CDDP (10 mg/kg) subgroup, CDDP (10 mg/kg) + SalB (1 µM) subgroup at random, CDDP (10 mg/kg) + SalB (5 µM) subgroup and CDDP (10 mg/kg) + SalB (10 µM) subgroup, Nicotinic Acid Riboside (NAR, 5 µM), with 6 rats in each subgroup. The cardiac function of rats in each subgroup was estimated by echocardiography, and hematoxylin-eosin (HE) staining and Masson staining corroborated the pathological changes of cardiac tissue. Biochemical kits were utilized for detecting the lactate dehydrogenase (LDH), creatine kinase (CK), interleukin-1ß (IL-1ß), IL-18, and caspase-1 concentrations in serum, superoxide dismutase (SOD), and malondialdehyde (MDA) in myocardial tissue, TdT-mediated dUTP Nick-End Labeling (TUNEL) staining, and flow cytometry were utilized for estimating the apoptosis level in myocardial tissue, western blot was used for estimating caspase-3, Bcl2-Associated X (Bax) levels in myocardial tissue and proteins levels related to Nuclear factor E2 related factor 2 (Nrf2) signal pathway. RESULTS: CDDP-induced cardiac dysfunction, myocardial injury, boosted LDH and CK levels in serum (p < 0.05), memorably increased oxidative stress level in myocardial tissue (p < 0.05), boosted inflammatory response (p < 0.05), boosted apoptosis rate of cardiomyocytes (p < 0.05), and declined the Nrf2, NAD(P)H quinone oxidoreductase 1 (NQO1), heme oxygenase 1 (HO-1) protein levels (p < 0.05). Interestingly, SalB remedy could alleviate the changes caused by CDDP in the above parameters, significantly decrease the level of myocardial oxidative stress and apoptosis (p < 0.05). CONCLUSIONS: SalB ameliorates the injury of cardiomyocytes induced by chemotherapy through oxidative stress mediated by the Nrf2/antioxidant response element (ARE) signal pathway.

The FGG c.952G>A variant causes congenital dysfibrinogenemia characterized by recurrent cerebral infarction: a case report.

Background: Congenital dysfibrinogenemia (CD) is a rare hereditary coagulation disorder resulting from mutations in fibrinogen genes. CD primarily presents with bleeding symptoms, but it can also lead to thrombotic events, including ischemic stroke. Case presentation: This report describes the case of a 52-year-old Chinese man who was admitted to the hospital twice due to recurrent cerebral infarction, characterized by sudden speech impairment and weakness in the right upper extremity. Brain MRI revealed multiple ischemic changes, predominantly in the left frontal and parietal lobes. Coagulation tests demonstrated reduced plasma fibrinogen (Clauss method), prolonged prothrombin time and thrombin time, and an elevated international normalized ratio. However, the ELISA assay indicated elevated levels of fibrinogen γ-chain protein. Despite a 2-month-old treatment regimen with aspirin, clopidogrel, and atorvastatin after the first hospitalization, the patient experienced a second ischemic stroke. Genetic analysis using whole-exome sequencing (WES) and Sanger sequencing identified a rare heterozygous missense variation, FGG c.952G>A (rs267606810), in both the stroke patient and his asymptomatic sister. Both individuals exhibited the same alterations in fibrinogen, characterized by reduced functional levels but increased antigenic protein. Subsequently, the patient was diagnosed with ischemic stroke associated with congenital dysfibrinogenemia. Conclusion: This case report expands the clinical phenotype spectrum associated with FGG c.952G>A (rs267606810) and underscores the significance of considering CD as a potential etiology for unexplained ischemic stroke, particularly in patients with a family history of coagulation disorders.

A light-driven enzymatic enantioselective radical acylation.

Enzymes are recognized as exceptional catalysts for achieving high stereoselectivities1-3, but their ability to control the reactivity and stereoinduction of free radicals lags behind that of chemical catalysts4. Thiamine diphosphate (ThDP)-dependent enzymes5 are well-characterized systems that inspired the development of N-heterocyclic carbenes (NHCs)6-8 but have not yet been proved viable in asymmetric radical transformations. There is a lack of a biocompatible and general radical-generation mechanism, as nature prefers to avoid radicals that may be harmful to biological systems9. Here we repurpose a ThDP-dependent lyase as a stereoselective radical acyl transferase (RAT) through protein engineering and combination with organophotoredox catalysis10. Enzyme-bound ThDP-derived ketyl radicals are selectively generated through single-electron oxidation by a photoexcited organic dye and then cross-coupled with prochiral alkyl radicals with high enantioselectivity. Diverse chiral ketones are prepared from aldehydes and redox-active esters (35 examples, up to 97% enantiomeric excess (e.e.)) by this method. Mechanistic studies reveal that this previously elusive dual-enzyme catalysis/photocatalysis directs radicals with the unique ThDP cofactor and evolvable active site. This work not only expands the repertoire of biocatalysis but also provides a unique strategy for controlling radicals with enzymes, complementing existing chemical tools.

Hsa_Circ_0001947/MiR-661/DOK7 Axis Restrains Non-Small Cell Lung Cancer Development.

Hsa_circ_0001947 is associated with multiple cancers, but its function in non-small cell lung cancer (NSCLC) is ambiguous and needs further research. The targeting relationship among circ_0001947, miR-661, and downstream of tyrosine kinase 7 (DOK7) was predicted by database and further verified by dual-luciferase reporter assay, while their expressions in cancer tissues and cells were detected by quantitative real-time polymerase chain reaction (qRT-PCR). After transfection, cell biological behaviors and expressions of miRNAs, miR-661 and DOK7 were determined by cell function experiments and qRT-PCR, respectively. Circ_0001947 was low-expressed in NSCLC tissues and cells. Circ_0001947 knockdown intensified cell viability and proliferation, induced cell cycle arrest at S phase, suppressed apoptosis and evidently enhanced miR-510, miR-587, miR-661 and miR-942 levels, while circ_0001947 overexpression did the opposite. MiR-661 was a target gene of circ_0001947 that participated in the regulation of circ_0001947 on cell biological behaviors. Furthermore, DOK7, the target gene of miR-661, partly participated in the regulation of miR-661 on cell viability. Hsa_circ_0001947 acts as a sponge of miR-661 to repress NSCLC development by elevating the expression of DOK7.

KIF18b-dependent hypomethylation of PARPBP gene promoter enhances oxaliplatin resistance in colorectal cancer.

As the new platinum drug oxaliplatin has been widely used in clinical treatment of colorectal cancer (CRC), oxaliplatin resistance has become a burning problem. In this study, higher expression of PARP-1 binding protein (PARPBP) was detected in oxaliplatin-resistant CRC (OR-CRC) cells than in non-resistant cells. Further research showed that kinesin family member 18 b (KIF18b) induced the overexpression of PARPBP, sustaining oxaliplatin resistance in OR-CRC cells. Through exploring the PARPBP gene promoter, we found that SP1-recruited DNMT3b methylated PARPBP promoter to suppress transcription in CRC cells, and increased KIF18b attenuated the recruitment of DNMT3b to PARPBP promoter by directly interacting with SP1 in OR-CRC cells. Clinical analysis suggested a positive relationship between KIF18b and PARPBP in CRC tissues and indicated poor prognosis in CRC patients with high level of KIF18b or PARPBP. In summary, KIF18b-induced PARPBP contributes to the resistant phenotype of OR-CRC.

Radiomic Feature-Based Nomogram: A Novel Technique to Predict EGFR-Activating Mutations for EGFR Tyrosin Kinase Inhibitor Therapy.

OBJECTIVES: To develop and validate a radiomic feature-based nomogram for preoperative discriminating the epidermal growth factor receptor (EGFR) activating mutation from wild-type EGFR in non-small cell lung cancer (NSCLC) patients. MATERIAL: A group of 301 NSCLC patients were retrospectively reviewed. The EGFR mutation status was determined by ARMS PCR analysis. All patients underwent nonenhanced CT before surgery. Radiomic features were extracted (GE healthcare). The maximum relevance minimum redundancy (mRMR) and LASSO, were used to select features. We incorporated the independent clinical features into the radiomic feature model and formed a joint model (i.e., the radiomic feature-based nomogram). The performance of the joint model was compared with that of the other two models. RESULTS: In total, 396 radiomic features were extracted. A radiomic signature model comprising 9 selected features was established for discriminating patients with EGFR-activating mutations from wild-type EGFR. The radiomic score (Radscore) in the two groups was significantly different between patients with wild-type EGFR and EGFR-activating mutations (training cohort: P<0.0001; validation cohort: P=0.0061). Five clinical features were retained and contributed as the clinical feature model. Compared to the radiomic feature model alone, the nomogram incorporating the clinical features and Radscore exhibited improved sensitivity and discrimination for predicting EGFR-activating mutations (sensitivity: training cohort: 0.84, validation cohort: 0.76; AUC: training cohort: 0.81, validation cohort: 0.75). Decision curve analysis demonstrated that the nomogram was clinically useful and surpassed traditional clinical and radiomic features. CONCLUSIONS: The joint model showed favorable performance in the individualized, noninvasive prediction of EGFR-activating mutations in NSCLC patients.

A novel indazole derivative, compound Cyy-272, attenuates LPS-induced acute lung injury by inhibiting JNK phosphorylation.

Acute lung injury (ALI) is a diffuse lung dysfunction disease characterized by high prevalence and high mortality. Thus far, no effective pharmacological treatment has been made for ALI in clinics. Inflammation is critical to the development of ALI. Therefore, anti-inflammation may be a potential therapy strategy for ALI. Indazole-containing derivatives, representing one of the most important heterocycles in drug molecules, are endowed with a broad range of biological properties, such as anti-cancer and anti-inflammation. In the current study, we investigated the biological effects of Cyy-272, a newly synthesized indazole compound, on LPS-induced ALI both in vivo and in vitro. Results show that Cyy-272 can inhibit the release of inflammatory cytokines in LPS-stimulated macrophage and alleviate LPS induced ALI. Further experiment revealed that Cyy-272 exhibit anti-inflammation activity by inhibiting JNK phosphorylation. Overall, our studies show that an indazole derivative, Cyy-272, is effective in suppressing LPS-induced JNK activation and inflammatory signaling.

Salvianolic acid B attenuated cisplatin-induced cardiac injury and oxidative stress via modulating Nrf2 signal pathway.

Cardiovascular complications have been well documented as the downside to conventional cancer chemotherapy. As a notable side effect of cisplatin (CDDP), cardiotoxicity represents a major obstacle to the successful treatment of cancer. It has been reported that Salvianolic acid B (SalB) possesses cardioprotective quality. However, the effect of SalB on cardiac damage caused by conventional cancer chemotherapy remains unclear. In this study, we clarified the protective effect of SalB on cisplatin-induced heart injury. Furthermore, in H9c2 cells, SalB dramatically reduced cisplatin-induced apoptosis and oxidative stress by modulating the nuclear factor erythroid-2-related factor 2 (Nrf2) signaling pathway. In conclusion, SalB had great potential in mitigating cisplatin-induced cardiac injury. Furthermore, more attention should be placed on natural active compounds containing SalB with antioxidant effects for the treatment of cardiomyopathy.

Characterization of lipid profiling in three parts (muscle, head and viscera) of tilapia (Oreochromis niloticus) using lipidomics with UPLC-ESI-Q-TOF-MS.

A lipidomic evaluation was performed on the tilapia muscle, head and viscera, including studying the composition, distribution and stereospecific characteristics of fatty acids and lipid species. The head and viscera lipids were significantly richer than the muscle lipids. Triacylglycerols were the predominant fraction (over 80% of total lipid in the muscle and head). Additionally, polyunsaturated fatty acids had higher percentages in phospholipids (30.35-52.05% of total fatty acids) than in triacylglycerols (18.11-25.15%). The C52:2 and C52:3 were the most abundant triacylglycerols, which indicates the potential application in infant food. Moreover, 622, 530 and 513 lipids were identified using ultraperformance liquid chromatography-quadrupole time-of-flight-mass spectrometry in the muscle, head and viscera, respectively. The three tilapia parts were distinguished using multivariate analysis. Five fatty acids and 33 lipid species were considered as the potential biomarkers. This comprehensive analysis will help to evaluate the lipid nutritional values and facilitate exploitation in tilapia consumption and processing.

Compound 15c, a Novel Dual Inhibitor of EGFRL858R/T790M and FGFR1, Efficiently Overcomes Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitor Resistance of Non-Small-Cell Lung Cancers.

In the past decades, epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) had been proved as an effective treatment strategy for the patients with EGFR-mutated non-small-cell lung cancer (NSCLC). However, the tolerance for the EGFR-TKI always occurred after continuous administration for a period of time and limiting the application of these drugs. Activation of FGFR1 signaling pathway was one of the important escape mechanisms for EGFR-TKI resistant in NSCLC. Here, a novel dual inhibitor of EGFRL858R/T790M and FGFR1, compound15c, was found and can efficiently overcame the EGFR-TKI resistance via its simultaneous inhibition of their kinase activities. Comparison with EGFRL858R/T790M and FGFR1 inhibitor treatment alone or combined revealed that the inhibition of EGFRL858R/T790M and FGFR1 activity by 15c was responsible for surmounting the intrinsic EGFR-TKI resistance in EGFRL858R/T790M-mutated H1975 cells and the acquired resistance in Afatinib-tolerant PC9 cells (AFA-PC9). Flow Cytometry and Caspase3 activity analysis assay showed that 15c induced significant the early apoptosis of H1975 cells. Xenograft tumor formation in BALB/c mice induced by a H1975 cells was suppressed by 15c treatment, with no changes in animal body weight. Generally, 15c may act as a new-generation EGFR-TKI for the therapy of NSCLC patients suffering a resistance to current TKI.

Longitudinal evaluation of serum periostin levels in patients after large-artery atherosclerotic stroke: A prospective observational study.

Increasing evidence supports the involvement of periostin in the pathophysiological processes of stroke and atherosclerosis. The aim of this study was to assess circulating periostin levels at different times after large-artery atherosclerotic (LAA) stroke and their association with stroke. Serum periostin levels were measured using enzyme-linked immunosorbent assay on day 1 in 162 patients with LAA stroke and in 108 age- and sex-matched controls, on day 6 after stroke in 134 patients, and during the 4th week after stroke in 46 of the 162 patients. Stroke severity was determined using the National Institutes of Health Stroke Scale (NIHSS), and the stroke volume was measured. Outcome at 3 months was measured using the modified Rankin Scale (mRS). Our results indicated that periostin levels increased significantly on day 6 after stroke, and this increasing trend persisted for at least 4 weeks after the event. In addition, the increase in periostin levels was positively correlated with the NIHSS scores and stroke volume, but not with the mRS scores after adjusting for the NIHSS scores. In conclusion, these findings suggest that the increase in serum periostin levels observed after stroke may be associated with the stroke severity in patients with LAA stroke.

NFYB-induced high expression of E2F1 contributes to oxaliplatin resistance in colorectal cancer via the enhancement of CHK1 signaling.

As a third-generation platinum drug, oxaliplatin has been widely applied in colorectal cancer (CRC); however, acquired resistance to oxaliplatin has become a major obstacle. In the present study, we found that the nuclear transcription factor Y subunit beta (NFYB) and E2F transcription factor 1 (E2F1) expression levels were significantly higher in oxaliplatin-resistant DLD1 and RKO CRC (OR-CRC) cells than in non-resistant cells. Additionally, highly expressed NFYB transactivated the E2F1 gene, which is important to maintain oxaliplatin resistance in OR-CRC cells. And Sirt1-dependent deacetylation suppresses the proapoptotic activity of E2F1 in OR-CRC cells. Through profiling the transcriptome of OR-CRC cells following E2F1 knockdown, CHK1 was identified as a target of E2F1. Deprivation of CHK1 sensitized OR-CRC cells to oxaliplatin. In vitro and in vivo phenotype experiments confirmed that an intact NFYB-E2F1-CHK1 axis was required to suppress oxaliplatin-induced apoptosis and maintain the tumorigenicity in OR-CRC cells. Knockdown of E2F1 in OR-CRC cells also decreased the expression of Pol κ, which was essential for CHK1 activation. Consistently, a high level of NFYB, E2F1, or CHK1 predicted poor survival in CRC patients, especially with oxaliplatin treatment. Collectively, the NFYB-E2F1 pathway displays a crucial role in the chemoresistance of OR-CRC by inducing the expression and activation of CHK1, providing a possible therapeutic target for oxaliplatin resistance in CRC.

Serum levels of endocan and endoglin are associated with large-artery atherosclerotic stroke.

BACKGROUND: Accumulating evidence has suggested that endocan and endoglin may play important roles in cardiovascular disease. However, no previous study has focused on these circulating levels in patients with large-artery atherosclerotic (LAA) stroke. METHODS: Serum levels of endocan and endoglin in 114 patients with LAA stroke and 114 age- and sex-matched controls were measured by ELISA. Serum samples from patients were available on day 1, day 6 and in the 4th week after ischaemic stroke(IS). Stroke severity was determined based on the NIHSS score and the stroke volume. An unfavourable outcome was defined as a mRS score>2 on day 90 after IS. RESULTS: The endocan levels were significantly higher in patients with LAA stroke compared with the controls (p=0.001), and after adjustment for other factors (p=0.001). In addition, higher endocan levels were independently associated with unfavourable outcomes on both day 1 and day 6 after IS (p=0.018 and p=0.011). Endoglin levels were decreased on day 6 (p=0.002) and then recovered in the 4th week after IS. No correlation was found between endocan or endoglin and stroke severity. CONCLUSIONS: Endocan levels are higher in patients with LAA stroke and can help in predicting the short-term unfavourable outcome. Endoglin levels are changed after stroke.

High serum levels of sclerostin and Dickkopf-1 are associated with acute ischaemic stroke.

BACKGROUND AND AIMS: Sclerostin and Dickkopf-1 (Dkk-1) are potent antagonists of Wnt signalling and might therefore play important roles in cardiovascular disease. We investigated whether serum sclerostin and Dkk-1 levels are associated with acute ischaemic stroke and specific stroke subtypes. METHODS: Serum levels of sclerostin and Dkk-1 were measured by ELISA on day 1 and on day 6 after stroke in 62 patients with large artery atherosclerotic (LAA) stroke, on day 1 after stroke in 62 age- and gender-matched patients with small-artery occlusion (SAO) stroke and on admission in 62 healthy controls. Stroke severity was determined based on the National Institutes of Health Stroke Scale (NIHSS) and by measuring stroke volume on diffusion-weighted imaging. Outcome was measured by the modified Rankin Scale (mRS) on day 90. RESULTS: Compared with controls, serum sclerostin and Dkk-1 levels were significantly higher in both patients with LAA stroke and with SAO stroke, and no difference was detected between the stroke subtypes. Sclerostin and Dkk-1 levels remained stable between the first and sixth day after stroke in the patients with LAA stroke. Receiver operating characteristic curve analysis was used to evaluate sclerostin and Dkk-1 as markers of a high risk of stroke and produced area under curve values of 0.773 and 0.776. Adjusted logistic regression showed that serum sclerostin and Dkk-1 levels remained as independent markers of stroke. No correlations were found between sclerostin or Dkk-1 levels and stroke severity or stroke outcome. CONCLUSIONS: High serum levels of sclerostin and Dkk-1 are associated with acute ischaemic stroke.

New EGFR inhibitor, 453, prevents renal fibrosis in angiotensin II-stimulated mice.

Chronic activation of renin-angiotensin system (RAS) greatly contributes to renal fibrosis through the over expression of angiotensin (Ang) II, ultimately leading to chronic kidney disease (CKD). As the main peptide in the RAS, Ang II is a key regulator of nephrotic inflammation, fibrogenic destruction and hypertensive nephropathy. Controlled by growth factors such as TGF-ß, Ang II is thought to be affected by other such growth factors including epidermal growth factor (EGF) due to its ability to stimulate growth, regulate angiogenesis, and desensitize cells from apoptotic stimuli. Here we show that epidermal growth factor receptor (EGFR) plays a key role in Ang II induced renal fibrosis and its inhibition for the use as an effective treatment of CKD. 453, an AG1478 analog, was used to block the EGF-EGFR interaction in vivo in 4-week old mice treated with Ang II and 453. Along with the inhibition of EGFR and its downstream signaling pathways (AKT and ERK), 453 also prevented the activation of fibrotic (collagen, CFGF, TGF-ß), inflammatory (COX2, IL-6, IL-1ß, TNF-α), apoptosis and oxidative stress pathways. These findings suggest the use of 453 as a novel EGFR-inhibitor for therapeutic use in CKD kidney dysfunction.

Curcumin analogue, A13, exhibits anti-leukemia effect via inhibiting STAT3.

Abnormal activation of signal transducer and activator of transcription 3 (STAT3) was reported in some leukemia, and inhibition of STAT3 can be the strategy for the leukemia treatment in clinic. In this study, we tested the anti-tumor effect of compound A13, a water-soluble analogue of curcumin, in vitro and in vivo. Herein, we show that A13 was able to reduce the viability of mastocytoma (P815 cells) and reticulum cell sarcoma (A20 cells) as measured by MTS assay. This effect was accompanied by a marked increase in the proportion of apoptotic cells as measured by flow cytometry. Furthermore, Western blot analysis suggested that the anti-leukemia effect of A13 was realized via STAT3 inhibition. In addition, systemic treatment with A13 in the A20-bearing mice for 60 days resulted in a significant improvement of survival rate and marked reduction of liver metastasis. In summary, our data show that the A13 treatment could effectively be applied to acute leukemia via inhibiting STAT3 signaling pathway.

Non-mitogenic form of acidic fibroblast growth factor protects against graft-versus-host disease without accelerating leukemia.

Acid fibroblast growth factor (aFGF) has been shown to prevent epithelial damage under various conditions, suggesting its potential to inhibit GVHD. However, because aFGF receptors are expressed on tumor cells, it may possibly offset the graft-vs.-tumor (GVT) effects of allogeneic bone marrow transplantation (allo-BMT). Here, we addressed these questions in a B6→B6D2F1 allo-BMT model. Although aFGF administration attenuated GVHD in non-leukemic recipients, aFGF treatment markedly accelerated death in mice that received recipient-type tumor (P815) cells along with allo- or syngeneic-BMT. Similar protection against GVHD was achieved by administration of a non-mitogenic form of aFGF (naFGF). Importantly, GVT effects were fully preserved in naFGF-treated recipients. Furthermore, aFGF, but not naFGF, significantly enhanced P815 cell proliferation both in vitro and in vivo. Our data indicate that the tumor-promoting, but not GVHD-protecting, effect of aFGF largely depends on its mitogenic activity, and suggest that naFGF may provide a safer approach to inhibiting GVHD in patients with malignancies.

20-Hydroxyeicosatetraenoic acid induces apoptosis in neonatal rat cardiomyocytes through mitochondrial-dependent pathways.

OBJECTIVE: 20-Hydroxyeicosatetraenoic acid (20-HETE), a [omega]-hydroxylation product of arachidonic acid catalyzed by cytochrome P450 4A, may play a role in the cardiovascular system. It is well known that cytochrome P450 [omega]-hydroxylase inhibitors markedly reduced the cardiac ischemia reperfusion injury. However, the direct effect of 20-HETE on cardiomyocytes is still poorly investigated. Here, we studied the effect of 20-HETE on cardiomyocyte apoptosis and the apoptosis-associated signaling pathways. METHODS AND RESULTS: The cardiomyocyte apoptosis was measured by fluorescein isothiocyanate conjugated annexin V/propidium iodide double staining cytometry, indicating that the percentage of early apoptotic cells increased from 15.6% +/- 2.6% to 25.5% +/- 2.5% in control and 20-HETE-treated cells, respectively. The mitochondrial membrane potential ([DELTA][PSI]m) was measured by detecting the ratio of JC-1 green/red emission intensity. A significant decrease in the ratio was observed after treatment with 20-HETE for 24 hours in comparison with control group, suggesting the disruptive effect of 20-HETE on mitochondrial [DELTA][PSI]m. In addition, 20-HETE stimulated caspase-3 activity and Bax mRNA expression in cardiomyocytes. In contrast, the Bcl-2 mRNA levels were significantly decreased by 20-HETE treatment. CONCLUSION: These results demonstrate that 20-HETE induces cardiomyocyte apoptosis by activation of several intrinsic apoptotic pathways. The 20-HETE-induced apoptosis could contribute to the cytochrome P450 [omega]-hydroxylase-dependent cardiac injure during cardiac ischemia-reperfusion.

20-HETE increases NADPH oxidase-derived ROS production and stimulates the L-type Ca2+ channel via a PKC-dependent mechanism in cardiomyocytes.

The production of 20-hydroxyeicosatetraenoic acid (20-HETE) is increased during ischemia-reperfusion, and inhibition of 20-HETE production has been shown to reduce infarct size caused by ischemia. This study was aimed to discover the molecular mechanism underlying the action of 20-HETE in cardiac myocytes. The effect of 20-HETE on L-type Ca(2+) currents (I(Ca,L)) was examined in rat isolated cardiomyocytes by patch-clamp recording in the whole cell mode. Superfusion of cardiomyocytes with 20-HETE (10-100 nM) resulted in a concentration-dependent increase in I(Ca,L), and this action of 20-HETE was attenuated by a specific NADPH oxidase inhibitor, gp91ds-tat (5 µM), or a superoxide scavenger, polyethylene glycol-superoxide dismutase (25 U/ml), suggesting that NADPH-oxidase-derived superoxide is involved in the stimulatory action of 20-HETE on I(Ca,L). Treatment of cardiomyocytes with 20-HETE (100 nM) increased both NADPH oxidase activity and superoxide production by approximately twofold. To study the molecular mechanism mediating the 20-HETE-induced increase in NADPH oxidase activity, PKC activity was measured in cardiomyocytes. Incubation of the cells with 20-HETE (100 nM) significantly increased PKC activity, and pretreatment of cardiomyocytes with a selective PKC inhibitor, GF-109203 (1 µM), attenuated the 20-HETE-induced increases in I(Ca,L) and in NADPH oxidase activity. In summary, 20-HETE stimulates NADPH oxidase-derived superoxide production, which activates L-type Ca(2+) channels via a PKC-dependent mechanism in cardiomyocytes. 20-HETE and 20-HETE-producing enzymes could be novel targets for the treatment of cardiac ischemic diseases.