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BACKGROUND: People with peripheral artery disease are at a high risk of major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Randomized controlled trials suggest that intensive lowering of low-density lipoprotein cholesterol (LDL-C) with proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors is an effective strategy to prevent these events. This study estimated the potential benefit and cost-effectiveness of administrating PCSK9 inhibitors to a cohort of participants with peripheral artery disease. METHODS: A total of 783 participants with intermittent claudication (IC; n = 582) or chronic limb-threatening ischemia (CLTI; n = 201) were prospectively recruited from three hospitals in Australia. Serum LDL-C was measured at recruitment, and the occurrence of MACE and MALE was recorded over a median (interquartile range) follow-up of 2.2 years (0.3-5.7 years). The potential benefit of administering a PCSK9 inhibitor was estimated by calculating the absolute risk reduction and numbers needed to treat (NNT) based on relative risk reductions reported in published randomized trials. The incremental cost-effectiveness ratio per quality-adjusted life year gained was estimated. RESULTS: Intensive LDL-C lowering was estimated to lead to an absolute risk reduction in MACE of 6.1% (95% confidence interval [CI], 2.0-9.3; NNT, 16) and MALE of 13.7% (95% CI, 4.3-21.5; NNT, 7) in people with CLTI compared with 3.2% (95% CI, 1.1-4.8; NNT, 32) and 5.3% (95% CI, 1.7-8.3; NNT, 19) in people with IC. The estimated incremental cost-effectiveness ratios over a 10-year period were $55,270 USD and $32,800 USD for participants with IC and CLTI, respectively. CONCLUSIONS: This analysis suggests that treatment with a PCSK9 inhibitor is likely to be cost-effective in people with CLTI.
Assuntos
Anticolesterolemiantes/economia , Anticolesterolemiantes/uso terapêutico , LDL-Colesterol/sangue , Custos de Medicamentos , Dislipidemias/tratamento farmacológico , Dislipidemias/economia , Claudicação Intermitente/economia , Claudicação Intermitente/terapia , Isquemia/economia , Isquemia/terapia , Doença Arterial Periférica/economia , Doença Arterial Periférica/terapia , Idoso , Anticolesterolemiantes/efeitos adversos , Biomarcadores/sangue , Doença Crônica , Análise Custo-Benefício , Regulação para Baixo , Dislipidemias/sangue , Dislipidemias/mortalidade , Feminino , Humanos , Claudicação Intermitente/mortalidade , Isquemia/mortalidade , Masculino , Pessoa de Meia-Idade , Inibidores de PCSK9 , Doença Arterial Periférica/mortalidade , Anos de Vida Ajustados por Qualidade de Vida , Queensland , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Austrália OcidentalRESUMO
Stressful events evoke long-term changes in behavioral responses; however, the underlying mechanisms in the brain are not well understood. Previous work has shown that epigenetic changes and immediate-early gene (IEG) induction in stress-activated dentate gyrus (DG) granule neurons play a crucial role in these behavioral responses. Here, we show that an acute stressful challenge [i.e., forced swimming (FS)] results in DNA demethylation at specific CpG (5'-cytosine-phosphate-guanine-3') sites close to the c-Fos (FBJ murine osteosarcoma viral oncogene homolog) transcriptional start site and within the gene promoter region of Egr-1 (early growth response protein 1) specifically in the DG. Administration of the (endogenous) methyl donor S-adenosyl methionine (SAM) did not affect CpG methylation and IEG gene expression at baseline. However, administration of SAM before the FS challenge resulted in an enhanced CpG methylation at the IEG loci and suppression of IEG induction specifically in the DG and an impaired behavioral immobility response 24 h later. The stressor also specifically increased the expression of the de novo DNA methyltransferase Dnmt3a [DNA (cytosine-5-)-methyltransferase 3 alpha] in this hippocampus region. Moreover, stress resulted in an increased association of Dnmt3a enzyme with the affected CpG loci within the IEG genes. No effects of SAM were observed on stress-evoked histone modifications, including H3S10p-K14ac (histone H3, phosphorylated serine 10 and acetylated lysine-14), H3K4me3 (histone H3, trimethylated lysine-4), H3K9me3 (histone H3, trimethylated lysine-9), and H3K27me3 (histone H3, trimethylated lysine-27). We conclude that the DNA methylation status of IEGs plays a crucial role in FS-induced IEG induction in DG granule neurons and associated behavioral responses. In addition, the concentration of available methyl donor, possibly in conjunction with Dnmt3a, is critical for the responsiveness of dentate neurons to environmental stimuli in terms of gene expression and behavior.
Assuntos
Metilação de DNA , Giro Denteado/metabolismo , Proteína 1 de Resposta de Crescimento Precoce/genética , Regulação da Expressão Gênica , Genes fos , S-Adenosilmetionina/farmacologia , Estresse Fisiológico/genética , Estresse Psicológico/genética , Animais , Ilhas de CpG , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA/efeitos dos fármacos , DNA Metiltransferase 3A , Giro Denteado/efeitos dos fármacos , Reação de Congelamento Cataléptica/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Genes Precoces/efeitos dos fármacos , Código das Histonas/efeitos dos fármacos , Masculino , Regiões Promotoras Genéticas/genética , Ratos , Ratos Wistar , NataçãoRESUMO
Background and Purpose- Current guidelines recommend prescription of a number of medications to prevent cardiovascular events in patients with peripheral artery disease (PAD). The impact that these medications have on the incidence of stroke in PAD patients has not been thoroughly investigated. This study aimed to investigate the association of prescription of antihypertensive drugs, antiplatelet medications, and statins, as well as cardiovascular disease risk factors, with stroke incidence in patients with symptoms of PAD. Methods- A database search was completed to identify studies reporting the incidence of stroke and prescription of antihypertensive drugs, antiplatelet medications, and statins in patients with PAD symptoms. A random-effects model was used to meta-analyze the incidence of stroke in patients with symptoms of PAD and in subgroups with intermittent claudication and critical limb ischemia. Metaregression was performed to explore the association between the incidence of stroke and the prescription of medications and the presence of cardiovascular disease risk factors. Results- Twelve studies including 67 915 patients with symptoms of PAD were included. A meta-analysis of data from 7 studies demonstrated an incidence of stroke of 1.31 per 100 patient-years. Patients with critical limb ischemia experienced stroke 2.3× more frequently than those with intermittent claudication (95% CI, 1.58-3.36; P<0.01). The reported prescription of antihypertensive agents varied between 10% and 71%, antiplatelet drugs between 49% and 90%, and statins between 11% and 79% in different studies. Metaregression suggested an association between a lower incidence of stroke and the prescription of antiplatelet drugs ( R2=0.81, P<0.01), and statins ( R2=0.85, P<0.01), but not antihypertensives medications. A prior history of cerebrovascular events was associated with a higher incidence of stroke ( R2=0.58, P<0.05). Conclusions- This review supports previous research which suggests the need for more effective means of ensuring more widespread prescription of preventative medications in patients with PAD.
Assuntos
Anti-Hipertensivos/uso terapêutico , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Doença Arterial Periférica/tratamento farmacológico , Inibidores da Agregação Plaquetária/uso terapêutico , Acidente Vascular Cerebral/epidemiologia , Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/epidemiologia , Humanos , Incidência , Doença Arterial Periférica/epidemiologia , Análise de Regressão , Prevenção SecundáriaRESUMO
BACKGROUND: Acute ischemic stroke is a leading cause of death and disability worldwide. Unlike myocardial infarction, there is no current blood test to diagnose acute ischemic stroke. MicroRNAs (miRNAs) are very stable in the blood and have been suggested as potential diagnostic markers. MATERIALS AND METHODS: This review aimed to systematically assess case-control studies investigating the association of circulating miRNAs with acute ischemic stroke. Medline, CINAHL, Cochrane Library, Web of Science, Scopus, and PubMed were searched for studies that examined the association of circulating miRNAs in patients with acute ischemic stroke. Studies meeting specific inclusion and exclusion criteria (such as blood samples obtained within 24 hours of an acute ischemic stroke) were selected for data extraction. Two authors extracted data from the included studies relevant to the study design, the patient characteristics, and the relative miRNA expression. RESULTS: Eight studies were included involving 572 cases and 431 healthy controls. Twenty-two miRNAs (12 upregulated and 10 downregulated) were reported as differentially expressed. Only 1 miRNA, miR-106b, was reported as differentially expressed in at least 2 studies. Significant heterogeneity in the design and methods of the included studies was noted. CONCLUSIONS: Differential expression of a large number of miRNAs has been reported early following acute ischemic stroke. More research is required in larger patient populations to further evaluate the diagnostic potential of the reported miRNAs.
Assuntos
Isquemia Encefálica/genética , MicroRNA Circulante/genética , Acidente Vascular Cerebral/genética , Adulto , Idoso , Isquemia Encefálica/sangue , Isquemia Encefálica/diagnóstico , Estudos de Casos e Controles , MicroRNA Circulante/sangue , Feminino , Marcadores Genéticos , Humanos , Masculino , Pessoa de Meia-Idade , Técnicas de Diagnóstico Molecular , Valor Preditivo dos Testes , Prognóstico , Acidente Vascular Cerebral/sangue , Acidente Vascular Cerebral/diagnóstico , Fatores de TempoRESUMO
BACKGROUND: Although glucocorticoid receptors (GRs) in the hippocampus play a vital role in the regulation of physiological and behavioural responses to stress, the regulation of receptor expression remains unclear. This work investigates the molecular mechanisms underpinning stress-induced changes in hippocampal GR mRNA levels in vivo. METHODS: Male Wistar rats were killed either under baseline conditions or after forced swim stress (FSS; 15 min in 25°C water). Rat hippocampi were micro-dissected (for mRNA, microRNA, and DNA methylation analysis) or frozen whole (for chromatin immunoprecipitation). In an additional experiment, rats were pre-treated with RU486 (a GR antagonist) or vehicle. RESULTS: FSS evoked a dentate gyrus-specific reduction in GR mRNA levels. This was related to an increased DNMT3a protein association with a discreet region of the Nr3c1 (GR gene) promoter, shown here to undergo increased DNA methylation after FSS. FSS also caused a time-dependent increase in the expression of miR-124a, a microRNA known to reduce GR mRNA expression, which was inversely correlated with a reduction in GR mRNA levels 30 min after FSS. FSS did not affect GR binding to a putative negative glucocorticoid response element within the Nr3c1 gene. CONCLUSIONS: Acute stress results in decreased GR mRNA expression specifically in the dentate gyrus. Our results indicate that a complex interplay of multiple molecular mechanisms - including increased DNA methylation of discrete CpG residues within the Nr3c1 gene, most likely facilitated by DNMT3a, and increased expression of miR-124a - could be responsible for these changes.
Assuntos
Metilação de DNA , Giro Denteado/metabolismo , MicroRNAs/genética , Receptores de Glucocorticoides/genética , Estresse Psicológico/genética , Doença Aguda , Animais , DNA (Citosina-5-)-Metiltransferases/genética , DNA Metiltransferase 3A , Regulação para Baixo , Expressão Gênica , Masculino , Mifepristona/administração & dosagem , Regiões Promotoras Genéticas , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Receptores de Glucocorticoides/antagonistas & inibidoresRESUMO
Athero-thrombosis of the arteries supplying the brain and lower limb are the main causes of stroke and limb loss. New therapies are needed to improve the outcomes of athero-thrombosis. Recent evidence suggests a role for epigenetic changes in the development and progression of ischaemic injury due to atherosclerotic occlusion of peripheral arteries. DNA hypermethylation have been associated with cardiovascular diseases. Histone post-translational modifications have also been implicated in atherosclerosis. Oxidized low-density lipoprotein regulated pro-inflammatory gene expression within endothelial cells is controlled by phosphorylation/acetylation of histone H3 and acetylation of histone H4 for example. There are a number of challenges in translating the growing evidence implicating epigenetics in atherosclerosis to improved therapies for patients. These include the small therapeutic window in conditions such as acute stroke and critical limb ischaemia, since interventions introduced in such patients need to act rapidly and be safe in elderly patients with many co-morbidities. Pre-clinical animal experiments have also reported conflicting effects of some novel epigenetic drugs, which suggest that further in-depth studies are required to better understand their efficacy in resolving ischaemic injury. Effective ways of dealing with these challenges are needed before epigenetic approaches to therapy can be introduced into practice.
Assuntos
Epigênese Genética , Arteriosclerose Intracraniana/genética , Doença Arterial Periférica/genética , Animais , Montagem e Desmontagem da Cromatina , Metilação de DNA , Epigênese Genética/efeitos dos fármacos , Regulação da Expressão Gênica , Predisposição Genética para Doença , Hemodinâmica , Humanos , Arteriosclerose Intracraniana/tratamento farmacológico , Arteriosclerose Intracraniana/metabolismo , Arteriosclerose Intracraniana/fisiopatologia , MicroRNAs/metabolismo , Doença Arterial Periférica/tratamento farmacológico , Doença Arterial Periférica/metabolismo , Doença Arterial Periférica/fisiopatologia , Fenótipo , Fatores de RiscoRESUMO
Stressful events are known to have a long-term impact on future behavioral stress responses. Previous studies suggested that both glucocorticoid hormones and glutamate acting via glucocorticoid receptors (GRs) and N-methyl D-aspartate (NMDA) receptors, respectively, are of critical importance for the consolidation of these long-lasting behavioral responses at the dentate gyrus, the gateway of the hippocampal formation. We found that an acute psychologically stressful event resulted in ERK1/2 phosphorylation (pERK1/2), which within 15 min led to the activation of the nuclear kinases MSK1 and Elk-1 in granule neurons of the dentate gyrus. Next, MSK1 and Elk-1 activation evoked serine-10 phosphorylation and lysine-14 acetylation in histone H3, resulting in the induction of the neuroplasticity-associated immediate-early genes c-Fos and Egr-1 in these neurons. The pERK1/2-mediated activation of MSK1 and Elk-1 required a rapid protein-protein interaction between pERK1/2 and activated GRs. This is a unique nongenomic mechanism of glucocorticoid hormone action in dentate gyrus granule neurons on long-lasting behavioral responses to stress involving direct cross-talk of GRs with ERK1/2-MSK1-Elk-1 signaling to the nucleus.
Assuntos
Comportamento Animal/fisiologia , Receptores de Glucocorticoides/metabolismo , Transdução de Sinais , Estresse Psicológico/metabolismo , Animais , Giro Denteado , Masculino , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Ratos , Ratos Wistar , Receptor Cross-Talk , Proteínas Quinases S6 Ribossômicas 90-kDa/metabolismo , Proteínas Elk-1 do Domínio ets/metabolismoRESUMO
Ischaemic stroke results in the formation of a cerebral infarction bordered by an ischaemic penumbra. Characterising the proteins within the ischaemic penumbra may identify neuro-protective targets and novel circulating markers to improve patient care. This review assessed data from studies using proteomic platforms to compare ischaemic penumbra tissues to controls following experimental stroke in animal models. Proteins reported to differ significantly between penumbra and control tissues were analysed in silico to identify protein-protein interactions and over-represented pathways. Sixteen studies using rat (n = 12), mouse (n = 2) or primate (n = 2) models were included. Heterogeneity in the design of the studies and definition of the penumbra were observed. Analyses showed high abundance of p53 in the penumbra within 24 hours of permanent ischaemic stroke and was implicated in driving apoptosis, cell cycle progression, and ATM- MAPK- and p53- signalling. Between 1 and 7 days after stroke there were changes in the abundance of proteins involved in the complement and coagulation pathways. Favourable recovery 1 month after stroke was associated with an increase in the abundance of proteins involved in wound healing. Poor recovery was associated with increases in prostaglandin signalling. Findings suggest that p53 may be a target for novel therapeutics for ischaemic stroke.
RESUMO
Cardiovascular diseases (CVDs) are a significant burden globally and are especially prevalent in obese and/or diabetic populations. Epicardial adipose tissue (EAT) surrounding the heart has been implicated in the development of CVDs as EAT can shift from a protective to a maladaptive phenotype in diseased states. In diabetic and obese patients, an elevated EAT mass both secretes pro-fibrotic/pro-inflammatory adipokines and forms intramyocardial fibrofatty infiltrates. This narrative review considers the proposed pathophysiological roles of EAT in CVDs. Diabetes is associated with a disordered energy utilization in the heart, which promotes intramyocardial fat and structural remodeling. Fibrofatty infiltrates are associated with abnormal cardiomyocyte calcium handling and repolarization, increasing the probability of afterdepolarizations. The inflammatory phenotype also promotes lateralization of connexin (Cx) proteins, undermining unidirectional conduction. These changes are associated with conduction heterogeneity, together creating a substrate for atrial fibrillation (AF). EAT is also strongly implicated in coronary artery disease (CAD); inflammatory adipokines from peri-vascular fat can modulate intra-luminal homeostasis through an "outside-to-inside" mechanism. EAT is also a significant source of sympathetic neurotransmitters, which promote progressive diastolic dysfunction with eventual cardiac failure. Further investigations on the behavior of EAT in diabetic/obese patients with CVD could help elucidate the pathogenesis and uncover potential therapeutic targets.
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Antibodies to the six chicken histone H1 subtypes and the variant histone H5 have been used in immunoprecipitations of crosslinked chromatin fragments (xChIPs) to map linker histones across the ß-globin locus and the widely expressed glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and carbonic anhydrase (CA) genes in three cell types: 15-day embryo chicken erythrocytes, 15-day embryo chicken brain and the early erythroid cell line HD24. In erythrocytes, where the ß-adult and ß-hatching genes are active, the H1.01, H1.11L and H1.11R subtypes are substantially depleted throughout the ß-globin locus and the neighboring heterochromatin, in contrast to the other four subtypes, in particular the more abundant H5. Active genes therefore carry high levels of some but not all linker histone subtypes. The situation is similar in HD24 cells, except that substantial depletions are found at the promoters of the adult ß(A) and embryonic ß(ρ) and ß(ε) genes, despite these genes not yet being active in HD24 cells. The distributions in the brain tissue are characterised by the absence of H1.02, H1.03 and H5 from the hypersensitive site HS3 and from the ß-adult 3' enhancer for the H1.11L and H1.11R subtypes. The data show that although linker histone subtypes play distinct cell-type specific roles in gene regulation, their widespread distribution indicates they are not intrinsically inhibitory to basic chromatin transactions.
Assuntos
Histonas/genética , Histonas/metabolismo , Proteínas Repressoras/metabolismo , Animais , Embrião de Galinha , Imunoprecipitação da Cromatina , Mapeamento Cromossômico/métodos , Reagentes de Ligações Cruzadas/farmacologia , Regulação da Expressão Gênica , Loci Gênicos , Humanos , Ligação Proteica , Sequências Reguladoras de Ácido Nucleico/fisiologia , Proteínas Repressoras/classificação , Proteínas Repressoras/imunologia , Globinas beta/genética , Globinas beta/metabolismoRESUMO
Epigenetic mechanisms are processes at the level of the chromatin that control the expression of genes but their role in neuro-immuno-endocrine communication is poorly understood. This review focuses on epigenetic modifications induced by a range of stressors, both physical and psychological, and examines how these variations can affect the biological activity of cells. It is clear that epigenetic modifications are critical in explaining how environmental factors, which have no effect on the DNA sequence, can have such profound, long-lasting influences on both physiology and behavior. A signaling pathway involving activation of MEK-ERK1/2, MSK1, and Elk-1 signaling molecules has been identified in the hippocampus which results in the phospho-acetylation of histone H3 and modification of gene expression including up-regulation of immediate early genes such as c-Fos. This pathway can be induced by a range of challenging experiences including forced swimming, Morris water maze learning, fear conditioning and exposure to the radial maze. Glucocorticoid (GC) hormones, released as part of the stress response and acting via glucocorticoid receptors (GRs), enhance signaling through the ERK1/2/MSK1-Elk-1 pathway and thereby increase the impact on epigenetic and gene expression mechanisms. The role of synergetic interactions between these pathways in adaptive responses to stress and learning and memory paradigms is discussed, in addition we speculate on their potential role in immune function.
Assuntos
Adaptação Fisiológica/genética , Epigênese Genética , Estresse Fisiológico/genética , Estresse Psicológico/genética , Animais , Comportamento Animal/fisiologia , Condicionamento Psicológico/fisiologia , Medo/fisiologia , Aprendizagem em Labirinto/fisiologia , Estresse Psicológico/fisiopatologiaRESUMO
Atrial fibrillation is very common among the elderly and/or obese. While myocardial fibrosis is associated with atrial fibrillation, the exact mechanisms within atrial myocytes and surrounding non-myocytes are not fully understood. This review considers the potential roles of myocardial fibroblasts and myofibroblasts in fibrosis and modulating myocyte electrophysiology through electrotonic interactions. Coupling with (myo)fibroblasts in vitro and in silico prolonged myocyte action potential duration and caused resting depolarization; an optogenetic study has verified in vivo that fibroblasts depolarized when coupled myocytes produced action potentials. This review also introduces another non-myocyte which may modulate both myocardial (myo)fibroblasts and myocytes: epicardial adipose tissue. Epicardial adipocytes are in intimate contact with myocytes and (myo)fibroblasts and may infiltrate the myocardium. Adipocytes secrete numerous adipokines which modulate (myo)fibroblast and myocyte physiology. These adipokines are protective in healthy hearts, preventing inflammation and fibrosis. However, adipokines secreted from adipocytes may switch to pro-inflammatory and pro-fibrotic, associated with reactive oxygen species generation. Pro-fibrotic adipokines stimulate myofibroblast differentiation, causing pronounced fibrosis in the epicardial adipose tissue and the myocardium. Adipose tissue also influences myocyte electrophysiology, via the adipokines and/or through electrotonic interactions. Deeper understanding of the interactions between myocytes and non-myocytes is important to understand and manage atrial fibrillation.
Assuntos
Tecido Adiposo/metabolismo , Fibrilação Atrial/patologia , Fibrose Endomiocárdica/patologia , Potenciais de Ação/fisiologia , Adipócitos/fisiologia , Adipocinas/fisiologia , Tecido Adiposo/patologia , Fibrilação Atrial/metabolismo , Cardiomiopatias/patologia , Fenômenos Eletrofisiológicos , Fibrose Endomiocárdica/metabolismo , Mapeamento Epicárdico/métodos , Fibroblastos/metabolismo , Fibroblastos/fisiologia , Fibrose/patologia , Coração/fisiologia , Átrios do Coração/patologia , Humanos , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/fisiologia , Miofibroblastos , Pericárdio/patologiaRESUMO
Inflammation, vascular smooth muscle cell apoptosis and oxidative stress are believed to play important roles in abdominal aortic aneurysm (AAA) pathogenesis. Human kallistatin (KAL; gene SERPINA4) is a serine proteinase inhibitor previously shown to inhibit inflammation, apoptosis and oxidative stress. The aim of this study was to investigate the role of KAL in AAA through studies in experimental mouse models and patients. Serum KAL concentration was negatively associated with the diagnosis and growth of human AAA. Transgenic overexpression of the human KAL gene (KS-Tg) or administration of recombinant human KAL (rhKAL) inhibited AAA in the calcium phosphate (CaPO4) and subcutaneous angiotensin II (AngII) infusion mouse models. Upregulation of KAL in both models resulted in reduction in the severity of aortic elastin degradation, reduced markers of oxidative stress and less vascular smooth muscle apoptosis within the aorta. Administration of rhKAL to vascular smooth muscle cells incubated in the presence of AngII or in human AAA thrombus-conditioned media reduced apoptosis and downregulated markers of oxidative stress. These effects of KAL were associated with upregulation of Sirtuin 1 activity within the aortas of both KS-Tg mice and rodents receiving rhKAL. These results suggest KAL-Sirtuin 1 signalling limits aortic wall remodelling and aneurysm development through reductions in oxidative stress and vascular smooth muscle cell apoptosis. Upregulating KAL may be a novel therapeutic strategy for AAA.
Assuntos
Aneurisma da Aorta Abdominal/prevenção & controle , Apoptose , Aterosclerose/prevenção & controle , Modelos Animais de Doenças , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Serpinas/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Animais , Aorta Abdominal/metabolismo , Aorta Abdominal/patologia , Aneurisma da Aorta Abdominal/etiologia , Aneurisma da Aorta Abdominal/metabolismo , Aneurisma da Aorta Abdominal/patologia , Aterosclerose/etiologia , Aterosclerose/metabolismo , Aterosclerose/patologia , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout para ApoE , Serpinas/sangueRESUMO
BACKGROUND: An animal model commonly used to investigate pathways and potential therapeutic interventions relevant to abdominal aortic aneurysm (AAA) involves subcutaneous infusion of angiotensin II within the apolipoprotein E deficient mouse. The aim of this study was to investigate genes differentially expressed in aneurysms forming within this mouse model in order to assess the relevance of this model to human AAA. RESULTS: Using microarrays we identified genes relevant to aneurysm formation within apolipoprotein E deficient mice. Firstly we investigated genes differentially expressed in the aneurysm prone segment of the suprarenal aorta in these mice. Secondly we investigated genes that were differentially expressed in the aortas of mice developing aneurysms relative to those that did not develop aneurysms in response to angiotensin II infusion. Our findings suggest that a host of inflammation and extracellular matrix remodelling pathways are upregulated within the aorta in mice developing aneurysms. Kyoto Encyclopedia of Genes and Genome categories enriched in the aortas of mice with aneurysms included cytokine-cytokine receptor interaction, leukocyte transendothelial migration, natural killer cell mediated cytotoxicity and hematopoietic cell lineage. Genes associated with extracellular matrix remodelling, such as a range of matrix metalloproteinases were also differentially expressed in relation to aneurysm formation. CONCLUSION: This study is the first report describing whole genome expression arrays in the apolipoprotein E deficient mice in relation to aneurysm formation. The findings suggest that the pathways believed to be critical in human AAA are also relevant to aneurysm formation in this mouse model. The findings therefore support the value of this model to investigate interventions and mechanisms of human AAA.
Assuntos
Angiotensina II/farmacologia , Aneurisma da Aorta Abdominal/genética , Apolipoproteínas E/deficiência , Expressão Gênica/efeitos dos fármacos , Estudo de Associação Genômica Ampla , Animais , Aneurisma da Aorta Abdominal/patologia , Apolipoproteínas E/genética , Modelos Animais de Doenças , Humanos , Masculino , Camundongos , Camundongos Knockout , Análise de Sequência com Séries de Oligonucleotídeos , Regulação para CimaRESUMO
Clinical studies report that low circulating angiopoietin-1 concentration at presentation predicts worse outcomes after ischaemic stroke. Upregulating angiopoietin-1 may therefore have therapeutic benefit for ischaemic stroke. This systematic review assessed whether upregulating angiopoietin-1 improved outcomes in rodent models of ischaemic stroke. Random-effects models quantified the effect of angiopoietin-1 upregulation on stroke severity in terms of the size of cerebral infarction and the extent of blood-brain barrier permeability. Eleven studies utilising rat and mouse models of ischaemic stroke fulfilled the inclusion criteria. Meta-analyses demonstrated that angiopoietin-1 upregulation significantly reduced cerebral infarction size (standardised mean difference: -3.02; 95% confidence intervals: -4.41, -1.63; p < 0.001; n = 171 animals) and improved blood-brain barrier integrity (standardized mean difference: -2.02; 95% confidence intervals: -3.27, -0.77; p = 0.002; n = 129 animals). Subgroup analyses demonstrated that angiopoietin-1 upregulation improved outcomes in models of transient, not permanent cerebral ischaemia. Six studies assessed the effect of angiopoietin-1 upregulation on neurological function; however, inter-study heterogeneity prevented meta-analysis. In conclusion, published rodent data suggest that angiopoietin-1 upregulation improves outcome following temporary cerebral ischaemia by reducing cerebral infarction size and improving blood-brain barrier integrity. Additional research is required to examine the effect of angiopoietin-1 upregulation on neurological function during stroke recovery and investigate the benefit and risks in patients.
Assuntos
Angiopoietina-1/biossíntese , Barreira Hematoencefálica , Infarto Cerebral , Acidente Vascular Cerebral , Regulação para Cima , Animais , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/patologia , Barreira Hematoencefálica/fisiopatologia , Infarto Cerebral/metabolismo , Infarto Cerebral/patologia , Infarto Cerebral/fisiopatologia , Modelos Animais de Doenças , Humanos , Camundongos , Ratos , Acidente Vascular Cerebral/metabolismo , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/fisiopatologiaRESUMO
BACKGROUND: With decreasing indication for abdominoperineal resection and an increase in sphincter preserving surgery, there is a growing population of patients who suffer from low anterior resection syndrome (LARS). The aim of this study is to use the LARS score to determine the prevalence of LARS at a regional centre in Australia and determine the effect of short- and long-course neoadjuvant therapy, anastomotic technique and interval from surgery will also be assessed. METHODS: Patients who had undergone an anterior resection (high, low or ultralow) at a regional centre over an 11-year period were identified. Eligible patients were contacted to complete a LARS score questionnaire. Results were analysed to determine the rate of major LARS and possible causative roles of certain patient and treatment-related variables. RESULTS: A total of 64 of 76 patients (84%) returned completed questionnaires. The prevalence of major LARS was 37.5%. Short-course neoadjuvant therapy appeared to be more likely to be associated with major LARS compared to long course (odds ratio (OR) = 2.4, 95% confidence interval (CI) 0.37-15.3, P = 0.35); however, this did not reach statistical significance. Rates of major LARS appear to decrease slowly over time and J-pouch colonic anastomosis appears to be slightly protective against major LARS (OR = 0.7, 95% CI 0.12-3.9, P = 0.70); however, neither results were statistically significant. CONCLUSION: The rate of major LARS at this regional centre is 37.5%. Larger prospective multicentre studies are required to determine impact of variables such as type of neoadjuvant therapy, anastomotic techniques and progression of LARS over time.
Assuntos
Diarreia/epidemiologia , Incontinência Fecal/epidemiologia , Complicações Pós-Operatórias/epidemiologia , Neoplasias Retais/cirurgia , Idoso , Austrália , Feminino , Instalações de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , SíndromeRESUMO
AIM: To summarize the reported prevalence and causative factors of Low Anterior Resection Syndrome (LARS) from studies using the LARS score. METHODS: A systematic literature search was conducted using Pubmed, Ovid Medline and the Cochrane database. Searches were performed using a combination of MeSH (medical subject headings) terms and key terms. Studies that were included used the LARS score as their primary collection tool. Studies were excluded if initial surgery was not for malignancy, or if the majority of LARS scores were from patients less than 1 year post initial surgery or closure of diverting stoma. Eligible studies were assessed with a validated quality assessment tool prior to performing a meta-analysis with quality effects model. Meta-analysis was conducted with prevalence estimates that had been transformed using the double arcsine method. RESULTS: Following the initial search and implementation of inclusion and exclusion criteria 11 studies were deemed suitable for meta-analysis. Meta-analysis found the estimated prevalence of major LARS was 41% (95% CI 34 -48). Where possible outlier studies were excluded, the prevalence was 42% (95%CI 35-48). Radiotherapy and tumour height were the most consistently assessed variables, both showing a consistent negative effect on bowel function. Defunctioning ileostomy was found to have a statically significant negative impact on bowel function in 4 of 11 studies. The majority of reported data has been produced by groups in Denmark and the United Kingdom with limited numbers provided by other locations. Available data is heterogenous with some variables having limited numbers, making meta-analysis of certain variables impossible. CONCLUSIONS: There is significant prevalence of Low Anterior Resection Syndrome following oncological rectal resection. A low anastomotic height or history of radiotherapy are major risk factors.
Assuntos
Colectomia/efeitos adversos , Complicações Pós-Operatórias/epidemiologia , Doenças Retais/epidemiologia , Neoplasias Retais/cirurgia , Idoso , Dinamarca/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Prevalência , Doenças Retais/etiologia , Fatores de Risco , Síndrome , Reino Unido/epidemiologiaRESUMO
Consolidation of contextual memories after a stressful encounter is essential for the survival of an organism and in allowing a more appropriate response to be elicited should the perceived threat reoccur. Recent evidence has explored the complex role that epigenetic mechanisms play in the formation of such memories, and the underlying signaling pathways are becoming more apparent. The glucocorticoid receptor (GR) has been shown to play a key role in these events having both genomic and non-genomic actions in the brain. GR has been shown to interact with the extracellular signal-regulated kinase mitogen-activated protein kinase (ERK MAPK) signaling pathway which, in concert, drives epigenetic modifications and chromatin remodeling, resulting in gene induction and memory consolidation. Evidence indicates that stressful events can have an effect on the offspring in utero, and that epigenetic marks altered early in life may persist into adulthood. A new and controversial area of research, however, suggests that epigenetic modifications could be inherited through the germline, a concept known as transgenerational epigenetics. This review explores the role that epigenetic processes play in the central nervous system, specifically in the consolidation of stress-induced memories, the concept of transgenerational epigenetic inheritance, and the potential role of epigenetics in revolutionizing the treatment of stress-related disorders through the emerging field of pharmacoepigenetics and personalized medical treatment.
RESUMO
Angiogenesis and inflammation are implicated in aortic aneurysm and atherosclerosis and regulated by angiopoietin-2 (Angpt2). The effect of Angpt2 administration on experimental aortic aneurysm and atherosclerosis was examined. Six-month-old male apolipoprotein E deficient (ApoE-/-) mice were infused with angiotensin II (AngII) and administered subcutaneous human Fc-protein (control) or recombinant Angpt2 (rAngpt2) over 14 days. Administration of rAngpt2 significantly inhibited AngII-induced aortic dilatation and rupture of the suprarenal aorta (SRA), and development of atherosclerosis within the aortic arch. These effects were blood pressure and plasma lipoprotein independent and associated with Tie2 activation and down-regulation of monocyte chemotactic protein-1 (MCP-1) within the SRA. Plasma concentrations of MCP-1 and interleukin-6 were significantly lower in mice receiving rAngpt2. Immunostaining for the monocyte/macrophage marker MOMA-2 and the angiogenesis marker CD31 within the SRA were less in mice receiving rAngpt2 than controls. The percentage of inflammatory (Ly6Chi) monocytes within the bone marrow was increased while that in peripheral blood was decreased by rAngpt2 administration. In conclusion, administration of rAngpt2 attenuated angiotensin II-induced aortic aneurysm and atherosclerosis in ApoE-/- mice associated with reduced aortic inflammation and angiogenesis. Up-regulation of Angpt2 may have potential therapeutic value in patients with aortic aneurysm and atherosclerosis.
Assuntos
Angiopoietina-2/metabolismo , Angiotensina II/metabolismo , Aneurisma da Aorta Abdominal/prevenção & controle , Aterosclerose/prevenção & controle , Neovascularização Fisiológica/fisiologia , Animais , Aterosclerose/genética , Quimiocina CCL2/biossíntese , Quimiocina CCL2/sangue , Humanos , Inflamação/prevenção & controle , Interleucina-6/sangue , Masculino , Camundongos , Camundongos Knockout para ApoE , Receptor TIE-2/metabolismoRESUMO
Making memories of a stressful life event is essential for an organism's survival as it allows it to adapt and respond in a more appropriate manner should the situation occur again. However, it may be envisaged that extremely stressful events can lead to formation of traumatic memories that are detrimental to the organism and lead to psychiatric disorders such as post-traumatic stress disorder (PTSD). The neurotransmitter glutamate and the ERK MAPK signaling pathway play a principal role in learning and memory. Glucocorticoid hormones acting via the glucocorticoid receptor have been shown to strengthen the consolidation of memories of stressful events. The ERK MAPK signaling pathway and glucocorticoid receptor-mediated actions have recently been shown to drive epigenetic modifications and conformational changes in the chromatin, stimulating the expression of neuroplasticity-related genes involved in stress-related learning and memory processes. The main epigenetic regulatory mechanisms are histone modifications and DNA (de-)methylation. Recently, studies have demonstrated that these processes are acting together in concert to regulate gene expression required for memory consolidation. This review explores the role of stress in learning and memory paradigms and the participating signaling pathways and epigenetic mechanisms and the enzymes that control these modifications during the consolidation process of memory formation.