The role of cardiovascular disease-associated iron overload in Libby amphibole-induced acute pulmonary injury and inflammation

Pulmonary toxicity induced by asbestos is thought to be mediated through redox-cycling of fiber-bound and bioavailable iron (Fe). We hypothesized that Libby amphibole (LA)-induced cute lung injury will be exacerbated in rat models of cardiovascular disease (CVD)-associated Fe-overload and oxidative stress. Healthy male Wistar Kyoto (WKY), spontaneously hypertensive (SH) and SH heart failure (SHHF) rats were intratracheally instilled with 0.0, 0.25 or 1.0 mg/rat LA and examined at 1 day, 1 week or 1 month. Although histologically it was not possible to distinguish severity differences between strains in LA-induced initial inflammation and later fibrosis, quantitative assessment of biomarkers showed strain-related differences. LA-induced neutrophilic inflammation was reversible in WKY but persisted more in SH and SHHF. Lung MIP-2 mRNA increased only in WKY at 1 day in response to LA but not in SH and SHHF. Bronchoalveolar lavage fluid (BALF) protein increased in SH but not WKY at 1 week and 1 month, while γ-glutamyltransferase and N-acetyl-β-D-glucosaminidase activities increased in all strains (WKY>SH=SHHF). BALF ferritin levels were high at baseline and increased following LA exposure only in SH and SHHF. Ferritin heavy chain mRNA increased only in SHHF at 1 day. At 1 month ferritin light chain mRNA declined from already high baseline levels in SHHF but increased in WKY and SH suggesting its differential involvement in LA-induced injury in Fe-overload. Unlike WKY, both SHHF and SH failed to increase the lung lining antioxidant, ascorbate, in response to LA. We conclude that underlying CVD-associated Fe-overload is likely linked to persistent lung injury, inflammation and antioxidant decompensation following LA exposure in rats.     

The role of iron in Libby amphibole-induced acute lung injury and inflammation

Complexation of host iron (Fe) on the surface of inhaled asbestos fibers has been postulated to cause oxidative stress contributing to in vivo pulmonary injury and inflammation. We examined the role of Fe in Libby amphibole (LA; mean length 4.99?µm ± 4.53 and width 0.28?µm ± 0.19) asbestos-induced inflammogenic effects in vitro and in vivo. LA contained acid-leachable Fe and silicon. In a cell-free media containing FeCl₃, LA bound #17 µg of Fe/mg of fiber and increased reactive oxygen species generation #3.5 fold, which was reduced by deferoxamine (DEF) treatment. In BEAS-2B cells exposure to LA, LA loaded with Fe (FeLA), or LA with DEF did not increase HO-1 or ferritin mRNA expression. LA increased IL-8 expression, which was reduced by Fe loading but increased by DEF. To determine the role of Fe in LA-induced lung injury in vivo, spontaneously hypertensive rats were exposed intratracheally to either saline (300 µL), DEF (1?mg), FeCl₃ (21 µg), LA (0.5?mg), FeLA (0.5?mg), or LA + DEF (0.5?mg). LA caused BALF neutrophils to increase 24?h post-exposure. Loading of Fe on LA but not chelation slightly decreased neutrophilic influx (LA + DEF > LA > FeLA). At 4?h post-exposure, LA-induced lung expression of MIP-2 was reduced in rats exposed to FeLA but increased by LA + DEF (LA + DEF > LA > FeLA). Ferritin mRNA was elevated in rats exposed to FeLA compared to LA. In conclusion, the acute inflammatory response to respirable fibers and particles may be inhibited in the presence of surface-complexed or cellular bioavailable Fe. Cell and tissue Fe-overload conditions may influence the pulmonary injury and inflammation caused by fibers.     

The role of iron in Libby amphibole-induced acute lung injury and inflammation

Complexation of host iron (Fe) on the surface of inhaled asbestos fibers has been postulated to cause oxidative stress contributing to in vivo pulmonary injury and inflammation. We examined the role of Fe in Libby amphibole (LA; mean length 4.99 μm ± 4.53 and width 0.28 μm ± 0.19) asbestos-induced inflammogenic effects in vitro and in vivo. LA contained acid-leachable Fe and silicon. In a cell-free media containing FeCl(3), LA bound #17 μg of Fe/mg of fiber and increased reactive oxygen species generation #3.5 fold, which was reduced by deferoxamine (DEF) treatment. In BEAS-2B cells exposure to LA, LA loaded with Fe (FeLA), or LA with DEF did not increase HO-1 or ferritin mRNA expression. LA increased IL-8 expression, which was reduced by Fe loading but increased by DEF. To determine the role of Fe in LA-induced lung injury in vivo, spontaneously hypertensive rats were exposed intratracheally to either saline (300 μL), DEF (1 mg), FeCl(3) (21 μg), LA (0.5 mg), FeLA (0.5 mg), or LA + DEF (0.5 mg). LA caused BALF neutrophils to increase 24 h post-exposure. Loading of Fe on LA but not chelation slightly decreased neutrophilic influx (LA + DEF > LA > FeLA). At 4 h post-exposure, LA-induced lung expression of MIP-2 was reduced in rats exposed to FeLA but increased by LA + DEF (LA + DEF > LA > FeLA). Ferritin mRNA was elevated in rats exposed to FeLA compared to LA. In conclusion, the acute inflammatory response to respirable fibers and particles may be inhibited in the presence of surface-complexed or cellular bioavailable Fe. Cell and tissue Fe-overload conditions may influence the pulmonary injury and inflammation caused by fibers.     

Acute phase response, inflammation and metabolic syndrome biomarkers of Libby asbestos exposure

Identification of biomarkers assists in the diagnosis of disease and the assessment of health risks from environmental exposures. We hypothesized that rats exposed to Libby amphibole (LA) would present with a unique serum proteomic profile which could help elucidate epidemiologically-relevant biomarkers. In four experiments spanning varied protocols and temporality, healthy (Wistar Kyoto, WKY; and F344) and cardiovascular compromised (CVD) rat models (spontaneously hypertensive, SH; and SH heart failure, SHHF) were intratracheally instilled with saline (control) or LA. Serum biomarkers of cancer, inflammation, metabolic syndrome (MetS), and the acute phase response (APR) were analyzed. All rat strains exhibited acute increases in α-2-macroglobulin, and α1-acid glycoprotein. Among markers of inflammation, lipocalin-2 was induced in WKY, SH and SHHF and osteopontin only in WKY after LA exposure. While rat strain- and age-related changes were apparent in MetS biomarkers, no LA effects were evident. The cancer marker mesothelin was increased only slightly at 1 month in WKY in one of the studies. Quantitative Intact Proteomic profiling of WKY serum at 1 day or 4 weeks after 4 weekly LA instillations indicated no oxidative protein modifications, however APR proteins were significantly increased. Those included serine protease inhibitor, apolipoprotein E, α-2-HS-glycoprotein, t-kininogen 1 and 2, ceruloplasmin, vitamin D binding protein, serum amyloid P, and more 1 day after last LA exposure. All changes were reversible after a short recovery regardless of the acute or long-term exposures. Thus, LA exposure induces an APR and systemic inflammatory biomarkers that could have implications in systemic and pulmonary disease in individuals exposed to LA.     

Effect of iron liposomes on anemia of inflammation

Supplementation with iron-fortified foods is an effective method for treating iron deficiency diseases. However, traditional iron agents used to treat anemia of inflammation (AI) have little effect. In this study, two types of iron liposomes, heme liposomes (HEME-LIP) and ferric citrate liposomes (FAC-LIP), were prepared by the rotary-evaporated film-ultrasonication method, and the encapsulation efficiencies, microstructures, size distributions and zeta potentials were assessed. Both types of iron liposomes showed stable physical characteristics. When used to treat rat models of AI, FAC-LIP and HEME-LIP could increase serum iron levels by 119% and 54% higher than did ferric citrate (FAC) and heme, respectively. Furthermore, the hepcidin, a key regulator of iron homeostasis was up-regulated by these iron liposomes, especially by HEME-LIP. These results indicate that the absorption of iron liposomes was improved over that of unencapsulated iron agents. Thus, iron liposomes may be used to fortify food in treating iron deficiency diseases, especially AI.     

输血相关性铁过载的临床结果

目的探讨依赖输血的慢性血液病铁过载临床结果。方法回顾性分析依赖输血(1年以上,≥50单位/例)的骨髓增生异常综合征(MDS)和再生障碍性贫血(AA)患者10例的临床表现、重要脏器功能、影像学变化、内分泌改变和血清铁蛋白(SF)浓度,了解体内铁负荷程度,去铁治疗及临床转归。结果 SF均明显增高(1830～4586ng/ml);8例患者肝功能异常,7例肝脏CT值增高。SF>3500ng/ml患者合并皮肤色素沉着,肝脾肿大和内分泌异常,其中的6例已经死亡。7例患者接受了15～60d去铁治疗,持续依赖输血者SF无下降。结论低危MDS和AA长期输血会导致输血性铁过载,严重者合并重要脏器功能及影像的异常,甚至死亡。去铁治疗宜在适时(SF>1000ng/ml)开始,并持续给予直到SF<1000ng/ml。     

Uncoupling and oxidative stress in liver mitochondria isolated from rats with acute iron overload

One hypothesis for the etiology of cell damage arising from iron overload is that its excess selectively affects mitochondria. Here we tested the effects of acute iron overload on liver mitochondria isolated from rats subjected to a single dose of i.p. 500 mg/kg iron–dextran. The treatment increased the levels of iron in mitochondria (from 21 ± 4 to 130 ± 7 nmol/mg protein) and caused both lipid peroxidation and glutathione oxidation. The mitochondria of iron-treated rats showed lower respiratory control ratio in association with higher resting respiration. The mitochondrial uncoupling elicited by iron-treatment did not affect the phosphorylation efficiency or the ATP levels, suggesting that uncoupling is a mitochondrial protective mechanism against acute iron overload. Therefore, the reactive oxygen species (ROS)/H⁺ leak couple, functioning as a mitochondrial redox homeostatic mechanism could play a protective role in the acutely iron-loaded mitochondria.     

铜、铁离子在癌形成中的作用

目的 :研究铜离子、铁离子在癌形成中的作用。方法 :测定96例癌症患者和36例健康对照血清中脂质过氧化物 (MDA)浓度、血清Cu、Fe离子浓度及总抗氧化力水平。结果 :本测定结果显示 :癌症患者MDA水平明显高于对照 ,癌症患者111例 (5 21±1 05)nmol/L;对照组36例 (4 04±0 68)nmol/L,两组比较P<0 001。总抗氧化力明显低于对照 ,癌症患者组 (4 39±0 98)U/L;对照组(5.78±0.93)U/L,(P<0 001)。两组比较癌症患者血清水平明显增高 (19.72±4.74)μmol/L;对照组 (14.92±2.71)μmol/L,两组比较P<0 001,但血清铁水平无显著变化。结论 :铜、铁离子可促进反应性氧类 (ROS)的产生 ,引发和 (或 )加速正常细胞恶性 ,促进癌的形成。     

Internalization of Libby amphibole asbestos and induction of oxidative stress in murine macrophages.

The community members of Libby, MT, have experienced significant asbestos exposure and developed numerous asbestos-related diseases including fibrosis and lung cancer due to an asbestos-contaminated vermiculite mine near the community. The form of asbestos in the contaminated vermiculite has been characterized in the amphibole family of fibers. However, the pathogenic effects of these fibers have not been previously characterized. The purpose of this study is to determine the cellular consequences of Libby amphibole exposure in macrophages compared to another well-characterized amphibole fiber; crocidolite asbestos. Our results indicate that Libby asbestos fibers are internalized by macrophages and localize to the cytoplasm and cytoplasmic vacuoles similar to crocidolite fibers. Libby asbestos fiber internalization generates a significant increase in intracellular reactive oxygen species (ROS) as determined by dichlorofluorescein diacetate and dihydroethidine fluorescence indicating that the superoxide anion is the major contributing ROS generated by Libby asbestos. Elevated superoxide levels in macrophages exposed to Libby asbestos coincide with a significant suppression of total superoxide dismutase activity. Both Libby and crocidolite asbestos generate oxidative stress in exposed macrophages by decreasing intracellular glutathione levels. Interestingly crocidolite asbestos, but not Libby asbestos, induces significant DNA damage in macrophages. This study provides evidence that the difference in the level of DNA damage observed between Libby and crocidolite asbestos may be a combined consequence of the distinct chemical compositions of each fiber as well as the activation of separate cellular pathways during asbestos exposure.     

Acute iron overload and oxidative stress in brain

An in vivo model in rat was developed by intraperitoneally administration of Fe-dextran to study oxidative stress triggered by Fe-overload in rat brain. Total Fe levels, as well as the labile iron pool (LIP) concentration, in brain from rats subjected to Fe-overload were markedly increased over control values, 6 h after Fe administration. In this in vivo Fe overload model, the ascorbyl (A)/ascorbate (AH^?) ratio, taken as oxidative stress index, was assessed. The A/AH^? ratio in brain was significantly higher in Fe-dextran group, in relation to values in control rats. Brain lipid peroxidation indexes, thiobarbituric acid reactive substances (TBARS) generation rate and lipid radical (LR) content detected by Electron Paramagnetic Resonance (EPR), in Fe-dextran supplemented rats were similar to control values. However, values of nuclear factor-kappaB deoxyribonucleic acid (NFκB DNA) binding activity were significantly increased (30%) after 8 h of Fe administration, and catalase (CAT) activity was significantly enhanced (62%) 21 h after Fe administration. Significant enhancements in Fe content in cortex (2.4 fold), hippocampus (1.6 fold) and striatum (2.9 fold), were found at 6 h after Fe administration. CAT activity was significantly increased after 8 h of Fe administration in cortex, hippocampus and striatum (1.4 fold, 86, and 47%, respectively). Fe response in the whole brain seems to lead to enhanced NF-κB DNA binding activity, which may contribute to limit oxygen reactive species-dependent damage by effects on the antioxidant enzyme CAT activity. Moreover, data shown here clearly indicate that even though Fe increased in several isolated brain areas, this parameter was more drastically enhanced in striatum than in cortex and hippocampus. However, comparison among the net increase in LR generation rate, in different brain areas, showed enhancements in cortex lipid peroxidation, without changes in striatum and hippocampus LR generation rate after 6 h of Fe overload. This information has potential clinical relevance, as it could be the key to understand specific brain damage occurring in conditions of Fe overload.     

高龄女性骨质疏松性骨折与血清铁过载的关系

目的探讨高龄女性髋部脆性骨折患者骨质疏松与临床铁过载的关系。方法检测30例高龄(≥70岁)脆性骨折女性(A组)和30例中青年(25~45岁)暴力骨折女性(B组)血清铁蛋白(FER)和髋部及腰椎骨密度T值。结果 A组FER均值269.97 ng/ml,明显高于B组的59.78ng/ml(P<0.01);A组髋部和腰椎T值分别为-2.35和-2.51,亦明显高于B组的0.08和0.32(P<0.01)。结论高龄女性骨质疏松患者血清铁过载是女性绝经后骨质疏松的一个重要相关因素。     

The role of inflammation in CNS injury and disease

For many years, the central nervous system (CNS) was considered to be 'immune privileged', neither susceptible to nor contributing to inflammation. It is now appreciated that the CNS does exhibit features of inflammation, and in response to injury, infection or disease, resident CNS cells generate inflammatory mediators, including proinflammatory cytokines, prostaglandins, free radicals and complement, which in turn induce chemokines and adhesion molecules, recruit immune cells, and activate glial cells. Much of the key evidence demonstrating that inflammation and inflammatory mediators contribute to acute, chronic and psychiatric CNS disorders is summarised in this review. However, inflammatory mediators may have dual roles, with detrimental acute effects but beneficial effects in long-term repair and recovery, leading to complications in their application as novel therapies. These may be avoided in acute diseases in which treatment administration might be relatively short-term. Targeting interleukin (IL)-1 is a promising novel therapy for stroke and traumatic brain injury, the naturally occurring antagonist (IL-1ra) being well tolerated by rheumatoid arthritis patients. Chronic disorders represent a greater therapeutic challenge, a problem highlighted in Alzheimer's disease (AD); significant data suggested that anti-inflammatory agents might reduce the probability of developing AD, or slow its progression, but prospective clinical trials of nonsteroidal anti-inflammatory drugs or cyclooxygenase inhibitors have been disappointing. The complex interplay between inflammatory mediators, ageing, genetic background, and environmental factors may ultimately regulate the outcome of acute CNS injury and progression of chronic neurodegeneration, and be critical for development of effective therapies for CNS diseases.     

Dioscin alleviates dimethylnitrosamine-induced acute liver injury through regulating apoptosis,oxidative stress and inflammation

In our previous study, the effects of dioscin against alcohol-, carbon tetrachloride- and acetaminophen-induced liver damage have been found. However, the activity of it against dimethylnitrosamine (DMN)-induced acute liver injury remained unknown. In the present study, dioscin markedly decreased serum ALT and AST levels, significantly increased the levels of SOD, GSH-Px, GSH, and decreased the levels of MDA, iNOS and NO. Mechanism study showed that dioscin significantly decreased the expression levels of IL-1β, IL-6, TNF-α, IκBα, p50 and p65 through regulating TLR4/MyD88 pathway to rehabilitate inflammation. In addition, dioscin markedly up-regulated the expression levels of SIRT1, HO-1, NQO1, GST and GCLM through increasing nuclear translocation of Nrf2 against oxidative stress. Furthermore, dioscin significantly decreased the expression levels of FasL, Fas, p53, Bak, Caspase-3/9, and upregulated Bcl-2 level through decreasing IRF9 level against apoptosis. In conclusion, dioscin showed protective effect against DMN-induced acute liver injury via ameliorating apoptosis, oxidative stress and inflammation, which should be developed as a new candidate for the treatment of acute liver injury in the future.     

STING介导的炎症在心血管疾病中的应用

干扰素刺激因子（STING）是固有免疫反应中的关键蛋白,介导免疫防御作用。此外,干扰素刺激因子参与多器官炎症反应,干扰素刺激因子通过胞质DNA感受器间接感知游离的DNA,激活IRF3或NF-κB,上调炎症水平。近年来,逐渐发现干扰素刺激因子介导的炎症反应促进心血管疾病中的病理进程。因此,研究干扰素刺激因子介导的炎症反应在心血管疾病中的作用,有望为心血管疾病提供新的治疗靶点。     

吸入不同浓度一氧化氮对急性肺损伤小鼠肺组织炎症反应的影响

目的　探讨吸入一氧化氮 (NO)对急性肺损伤 (ALI)小鼠肺组织炎症反应的影响。方法　脂多糖 (LPS)腹腔注射诱导小鼠ALI模型 ,吸入不同浓度NO ,测定肺组织核因子 (NF) κB活性及肿瘤坏死因子 (TNF)α、白介素 (IL) 1 0mRNA的表达。结果　与LPS组 (A组 )比较 ,LPS +吸入NO 5 ppm(B组 )、LPS +吸入NO 2 0 ppm(C组 ) 1 2小时湿重 /干重 (W /D)显著降低 ,LPS +吸入NO4 0ppm(D组 )无明显差异。LPS注射后肺组织NF κB活性明显增强 ,6小时达到峰值 4 0 6± 6 2 ,显著高于LPS注射前 (45± 31 ,P <0 0 5 )。吸入NO 5 ppm和 2 0 ppm 6小时后 ,NF κB活性明显低于LPS组 (P <0 0 5 )。但吸入 4 0ppmNF κB活性在 3小时、6小时明显下降后 ,1 2小时又明显升高。B组和C组肺组织TNF α和IL 1 0浓度及mRNA表达在 3～ 1 2小时均明显降低 ,但D组吸入NO 4 0 ppm1 2小时 ,TNF α表达与LPS组无显著差异。吸入NO后各组IL 1 0表达均降低。结论　吸入 5 ppm和 2 0ppmNO可抑制LPS介导的NF κB活化 ,下调炎症因子表达 ,改善ALI ,但吸入 4 0 ppmNO加重肺损伤。     

Lead-induced iron overload and attenuated effects of ferroportin 1 overexpression in PC12 cells

Lead (Pb) neurotoxicity has received renewed interest with the growing evidence that Pb contributes to Alzheimer’s disease (AD). However, the mechanism is not clear. In our previous study of long-term Pb exposure in vivo, a brain iron (Fe) overload induced by Pb was observed in elderly rats. It is well known that brain Fe overload is the mechanism of AD. Therefore, we have reason to believe that Pb induced Fe overload and caused neurodegenerative disease. However, the mechanism or route of Pb-induced Fe overload is unknown. In the current study, the effect of Pb exposure on Fe homeostasis in PC12 cells was determined at different Pb-exposure concentrations and periods with differing Fe exposure, and the role of ferroportin 1 (FP1), the sole iron efflux protein, in Pb-induced Fe metabolic disorders was further investigated. The results showed a Pb-induced cellular increase in Fe accompanying a decrease in the expression of FP1 in a concentration- and time-dependent manner in Pb-exposed PC12 cells. Furthermore, FP1 overexpression could attenuate Fe accumulation in Pb-exposed PC12 cells. These results indicated that FP1 might be a novel target to prevent cellular Fe accumulation induced by Pb exposure and subsequent neurotoxic consequences.     

Lead-induced iron overload and attenuated effects of ferroportin 1 overexpression in PC12 cells

Lead (Pb) neurotoxicity has received renewed interest with the growing evidence that Pb contributes to Alzheimer’s disease (AD). However, the mechanism is not clear. In our previous study of long-term Pb exposure in vivo, a brain iron (Fe) overload induced by Pb was observed in elderly rats. It is well known that brain Fe overload is the mechanism of AD. Therefore, we have reason to believe that Pb induced Fe overload and caused neurodegenerative disease. However, the mechanism or route of Pb-induced Fe overload is unknown. In the current study, the effect of Pb exposure on Fe homeostasis in PC12 cells was determined at different Pb-exposure concentrations and periods with differing Fe exposure, and the role of ferroportin 1 (FP1), the sole iron efflux protein, in Pb-induced Fe metabolic disorders was further investigated. The results showed a Pb-induced cellular increase in Fe accompanying a decrease in the expression of FP1 in a concentration- and time-dependent manner in Pb-exposed PC12 cells. Furthermore, FP1 overexpression could attenuate Fe accumulation in Pb-exposed PC12 cells. These results indicated that FP1 might be a novel target to prevent cellular Fe accumulation induced by Pb exposure and subsequent neurotoxic consequences.     

The role of interleukin-6 in pulmonary inflammation and injury induced by exposure to environmental air pollutants.

This study was designed to examine the role of the cytokine interleukin-6 (IL-6) in environmental air pollutant-induced pulmonary inflammation, injury, and repair. IL-6 knockout (KO) mice and wild-type (WT) mice were exposed to filtered air; aged and diluted cigarette smoke (ADSS), a surrogate for environmental tobacco smoke; ozone; or ADSS followed by ozone (ADSS/ozone). The proportion of monocytes and neutrophils recovered by bronchoalveolar lavage (BAL) as well as the level of total protein in BAL fluid were significantly increased in both IL-6 KO and WT mice following exposure to ozone or to ADSS/ozone. However, bromodeoxyuridine (BrdU) labeling within terminal bronchiolar epithelium and proximal alveolar regions in IL-6 KO mice exposed to ozone or to ADSS/ozone was significantly reduced compared with IL-6 sufficient mice (WT). WT mice treated with IL-6 antibodies also demonstrated a reduction in BrdU cell labeling similar to that observed in IL-6 KO mice following exposure to ozone or ADSS/ozone. Clara cell secretory protein (CCSP) abundance, a marker of Clara cell maturation and function, was markedly reduced in the terminal bronchiolar epithelium of WT mice following exposure to ADSS and/or ozone, whereas CCSP abundance was unchanged in IL-6 KO mice. We conclude that endogenous IL-6 in mice plays a critical role in the progress of lung inflammation/injury, but CCSP may also play a role to protect the lungs of mice exposed to toxic air pollutants. Data from this study further suggest that IL-6 antibody treatment modalities may be a means to attenuate pulmonary inflammation and injury.