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1.
Endocr Res ; 38(3): 125-138, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23167461

RESUMO

BACKGROUND: Low levels of serum testosterone in men are associated with cardiovascular disease. Clinical studies show that testosterone replacement therapy (TRT) can improve symptoms of cardiovascular disease and reduce the inflammatory burden evident in atherosclerosis. AIM: We used an in vivo animal model to determine whether testosterone influences mediators of vascular inflammation as part of its beneficial effects on atherogenesis. METHODS: Testicular-feminized (Tfm) mice, which express low endogenous testosterone and a non-functional androgen receptor (AR), were used to assess the effect of androgen status on atheroma formation, serum lipids, and inflammatory mediators. Tfm mice were fed a high-cholesterol diet, received saline or physiological (TRT), and were compared to saline-treated XY littermates. RESULTS: A total of 28 weeks of high-cholesterol diet caused fatty streak formation in the aortic root of XY littermates and Tfm mice, an effect significantly amplified in Tfm mice. Tfm mice on normal diet showed elevated serum tumor necrosis factor-α (TFN-α) and interleukin-6 compared to XY littermates. High-cholesterol diet induced increased monocyte chemoattractant protein-1 (MCP-1) in Tfm mice, and TFN-α and MCP-1 in XY littermates. TRT reduced fatty streak formation and serum interleukin-6 in Tfm mice but had no significant effects on lipid profiles. Monocyte/macrophage staining indicated local inflammation in aortic root fatty streak areas of all mice, with TRT reducing local inflammation through plaque reduction in Tfm mice. Fractalkine (CX3CL1) and its receptor (CX3CR1) were present in fatty streaks of all mice fed a high-cholesterol diet, independent of androgen status. CONCLUSION: These results are consistent with AR-dependent and AR-independent anti-inflammatory actions of testosterone in atheroprotection, although the local anti-inflammatory mechanisms via which testosterone acts remain unknown.

2.
Am Heart J ; 164(6): 893-901, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23194490

RESUMO

BACKGROUND: This study assessed the feasibility of a 12-week program of exercise, with and without intramuscular testosterone supplementation, in male patients with chronic heart failure (CHF) and low testosterone status and collected preliminary data for key health outcomes. METHODS: Male patients with CHF (n = 41, age 67.2 years, range 51-84 years) with mean ± SD testosterone levels of 10.7 ± 2.6 nmol/L (309 ± 76 ng/dL) were randomly allocated to exercise with testosterone or placebo groups. Feasibility was assessed in terms of recruitment, intervention compliance, and attrition. Outcomes included an incremental shuttle walk test, peak oxygen uptake, muscular strength, echocardiographic measures, N-terminal pro-brain natriuretic peptide, inflammatory markers, depression (Beck Depression Inventory), and health-related quality of life (Minnesota Living with Heart Failure Questionnaire and Medical Outcomes Study Short-Form). RESULTS: Attrition was 30% but with 100% compliance to exercise and injections in patients who completed the study. Similar improvements in shuttle walk test (18% vs 19%), body mass (-1.3 kg vs -1.0 kg), and hand grip strength (2.1 kg vs 2.5 kg) from baseline were observed in both groups. The exercise with testosterone group showed improvements from baseline in peak oxygen uptake (P < .01), Beck Depression Inventory (P < .05), leg strength (P < .05), and several Medical Outcomes Study Short-Form quality of life domains (P < .05), which were generally not apparent in the exercise with placebo group. Echocardiographic measures, N-terminal pro-brain natriuretic peptide, and inflammatory markers were mostly unchanged. CONCLUSIONS: This study shows for the first time that testosterone supplementation during a program of exercise rehabilitation is feasible and can positively impact on a range of key health outcomes in elderly male patients with CHF who have a low testosterone status.


Assuntos
Androgênios/administração & dosagem , Terapia por Exercício , Insuficiência Cardíaca/terapia , Testosterona/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Índice de Massa Corporal , Doença Crônica , Estudos de Coortes , Terapia Combinada , Depressão , Método Duplo-Cego , Ecocardiografia , Teste de Esforço , Estudos de Viabilidade , Insuficiência Cardíaca/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Força Muscular , Qualidade de Vida , Testosterona/sangue , Resultado do Tratamento , Reino Unido
3.
Postgrad Med J ; 88(1046): 706-12, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22745181

RESUMO

Heart failure is usually a relentless condition associated with a poor prognosis. Triggered by a physiological insult, maladaptive neurohumoral processes result in an ever-spiralling deterioration of cardiovascular function. However, there are certain underlying conditions which are associated with a temporary reduction in contractile function leading to reversible heart failure. These conditions affect a relatively small number of patients when compared with heart failure secondary to inherited cardiomyopathies and ischaemic heart disease. There are two broad mechanisms responsible for reversible myocyte dysfunction: acute inflammatory activation in which cytokines depress myocyte function, and toxic effects in which there is impairment of intra-cellular energetics. In this review, we discuss reversible heart failure caused by toxic effects. These effects can be caused by drugs (prescribed and illicit) and by tachycardic arrhythmia (tachycardiomyopathy), and are caused by abnormalities of mitochondrial function and myocytic calcium processing. The underlying pathological mechanisms, clinical features and management options are discussed, illustrated by clinical case studies.


Assuntos
Cardiomiopatias/complicações , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Insuficiência Cardíaca/etiologia , Inflamação/complicações , Taquicardia/complicações , Adulto , Cálcio/metabolismo , Feminino , Insuficiência Cardíaca/prevenção & controle , Humanos , Masculino , Pessoa de Meia-Idade , Mitocôndrias/fisiologia , Contração Miocárdica/fisiologia , Adulto Jovem
4.
Postgrad Med J ; 87(1024): 110-5, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21097545

RESUMO

Heart failure is increasingly common in western populations and is an inevitable consequence of the improved survival after myocardial infarction, and of an ageing population. Heart failure is usually relentlessly progressive as the maladaptive processes triggered by the physiological changes of the condition lead to further deterioration. However, in certain circumstances, heart failure is transient or potentially reversible when it occurs as part of intense systemic inflammatory activation. This review considers the role of inflammation in the aetiology of heart failure, and illustrates the strategies which have been used to modify the inflammatory response with anonymised clinical case reports.


Assuntos
Insuficiência Cardíaca/etiologia , Inflamação/complicações , Infarto do Miocárdio/complicações , Insuficiência Cardíaca/fisiopatologia , Humanos , Inflamação/fisiopatologia , Infarto do Miocárdio/fisiopatologia
6.
Circulation ; 116(21): 2427-34, 2007 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-17984376

RESUMO

BACKGROUND: Research supports a beneficial effect of physiological testosterone on cardiovascular disease. The mechanisms by which testosterone produces these effects have yet to be elucidated. The testicular feminized (Tfm) mouse exhibits a nonfunctional androgen receptor and low circulating testosterone concentrations. We used the Tfm mouse to determine whether testosterone modulates atheroma formation via its classic signaling pathway involving the nuclear androgen receptor, conversion to 17beta-estradiol, or an alternative signaling pathway. METHODS AND RESULTS: Tfm mice (n=31) and XY littermates (n=8) were separated into 5 experimental groups. Each group received saline (Tfm, n=8; XY littermates, n=8), physiological testosterone alone (Tfm, n=8), physiological testosterone in conjunction with the estrogen receptor alpha antagonist fulvestrant (Tfm, n=8), or physiological testosterone in conjunction with the aromatase inhibitor anastrazole (Tfm, n=7). All groups were fed a cholesterol-enriched diet for 28 weeks. Serial sections from the aortic root were examined for fatty streak formation. Blood was collected for measurement of total cholesterol, high-density lipoprotein cholesterol (HDLC), non-HDLC, testosterone, and 17beta-estradiol. Physiological testosterone replacement significantly reduced fatty streak formation in Tfm mice compared with placebo-treated controls (0.37+/-0.07% versus 2.86+/-0.39%, respectively; P < or = 0.0001). HDLC concentrations also were significantly raised in Tfm mice receiving physiological testosterone replacement compared with those receiving placebo (2.81+/-0.30 versus 2.08+/-0.09 mmol/L, respectively; P = 0.05). Cotreatment with either fulvestrant or anastrazole completely abolished the improvement in HDLC. CONCLUSION: Physiological testosterone replacement inhibited fatty streak formation in the Tfm mouse, an effect that was independent of the androgen receptor. The observed increase in HDLC is consistent with conversion to 17beta-estradiol.


Assuntos
Aterosclerose/prevenção & controle , HDL-Colesterol/sangue , Terapia de Reposição Hormonal/métodos , Receptores Androgênicos/fisiologia , Testosterona/fisiologia , Testosterona/uso terapêutico , Androgênios , Animais , Aterosclerose/sangue , Masculino , Camundongos , Camundongos Mutantes , Testosterona/administração & dosagem
8.
Drugs Aging ; 25(12): 1049-60, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19021303

RESUMO

The elderly are at particularly high risk for arterial and venous thromboembolism, both of which are associated with significant morbidity and mortality in this age group. However, this age group often receives inadequate thromboprophylaxis because of concerns about bleeding risk, which is often over-estimated, denying patients the benefit of proven antithrombotic regimens. Guidelines advocate active and comprehensive thromboprophylactic strategies across all age groups and recent studies have addressed age considerations in both arterial and venous embolic disorders. Pharmacological thromboprophylaxis has repeatedly been shown to have a favourable risk-benefit profile, including in elderly populations. The benefits of thromboprophylaxis have long been recognized in surgical patients and recent studies have confirmed the safety and efficacy of thromboprophylaxis in medical patients, with most trials having included elderly cohorts. Given the difficulties and inconvenience associated with use of current anticoagulants, new drugs are under development and whilst some have been associated with significant adverse effects, others have demonstrated low bleeding risks without the need for coagulation monitoring. Meanwhile, other new agents currently on the market, such as fondaparinux sodium, have gained license for use in orthopaedic and general surgery patients, although clinical experience with these agents in elderly populations is limited. This article discusses the latest developments and current opinions regarding thromboprophylaxis, with particular emphasis on its relevance to the elderly population.


Assuntos
Idoso/fisiologia , Anticoagulantes/uso terapêutico , Tromboembolia/prevenção & controle , Anticoagulantes/efeitos adversos , Humanos , Complicações Pós-Operatórias/prevenção & controle , Tromboembolia Venosa/prevenção & controle
9.
Diab Vasc Dis Res ; 5(2): 135-7, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18537102

RESUMO

The purpose of this study was to assess the effect of rosiglitazone on bioavailable, free and total testosterone levels in hypogonadal men with type 2 diabetes. Sixteen type 2 diabetic men with hypogonadism were studied before and after administration of rosiglitazone (8 mg/day) for six months, with assessments performed every two months on two consecutive days. We measured testosterone and sex hormone binding globulin (SHBG), visceral adiposity, high-sensitivity CRP (hs-CRP), lipids, microalbuminuria and blood pressure. There was a significant increase in free (p=0.01), bioavailable (p=0.007) and total testosterone (p=0.002), as well as SHBG (p=0.03) levels, with rosiglitazone treatment. Waist circumference and waist / hip ratio decreased with the improvement in insulin sensitivity and glycaemic control (p=0.01). There was also a significant reduction in hs-CRP (p=0.02) and urinary albumin excretion. No significant effect on blood pressure or the ratio of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol (LDL to HDL) was seen. In conclusion, the insulin-sensitiser rosiglitazone increases bioavailable, free and total testosterone and SHBG levels in hypogonadal men with type 2 diabetes.


Assuntos
Tamanho Corporal/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Hipogonadismo/tratamento farmacológico , Testosterona/sangue , Tiazolidinedionas/uso terapêutico , Adiposidade/efeitos dos fármacos , Adulto , Idoso , Albuminúria/etiologia , Albuminúria/prevenção & controle , Pressão Sanguínea , Proteína C-Reativa/metabolismo , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/fisiopatologia , Humanos , Hipogonadismo/complicações , Hipogonadismo/metabolismo , Hipogonadismo/fisiopatologia , Gordura Intra-Abdominal/efeitos dos fármacos , Lipídeos/sangue , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Rosiglitazona , Globulina de Ligação a Hormônio Sexual/metabolismo , Resultado do Tratamento , Regulação para Cima
10.
Eur J Heart Fail ; 9(1): 44-50, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16828341

RESUMO

Resistance to insulin occurs in chronic heart failure (CHF) and is related to prognosis. Studies of testosterone in non-(CHF) males suggest that physiological testosterone therapy improves insulin sensitivity. This was a single-blind placebo controlled crossover trial to determine the effect of testosterone replacement on insulin sensitivity in 13 men with moderate to severe CHF (ejection fraction 30.5+/-1.3). The primary outcome was the homeostatic model index (HOMA-IR) of fasting insulin sensitivity and secondary outcomes were body composition as measured by bioelectrical impedance and glucose tolerance to a standard 75 g oral glucose load. Analysis was performed on the delta values with the treatment effect of placebo compared with that of testosterone. At baseline HOMA-IR correlated with measures of body fat [% fat mass (rP=0.84, p=0.0001) and body mass index (rP=0.79, p=0.01)] but not with CHF severity. Testosterone reduced HOMA-IR (-1.9+/-0.8, p=0.03) indicating improved fasting insulin sensitivity. Testosterone also increased total mass (+1.5+/-0.5 kg, p=0.008) and decreased body fat (-0.8+/-0.3%, p=0.02). Testosterone improves fasting insulin sensitivity in men with CHF and may also increase lean body mass, these data suggest a favourable effect of testosterone on an important metabolic component of CHF.


Assuntos
Insuficiência Cardíaca/fisiopatologia , Resistência à Insulina/fisiologia , Insulina/farmacologia , Testosterona/farmacologia , Idoso , Idoso de 80 Anos ou mais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Pressão Sanguínea , Índice de Massa Corporal , Creatinina/sangue , Estudos Cross-Over , Jejum , Humanos , Masculino , Pessoa de Meia-Idade , Placebos , Método Simples-Cego
11.
Vascul Pharmacol ; 44(6): 427-33, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16624627

RESUMO

We determined the calcium signalling pathways involved in the mechanisms of contraction of the vasoconstrictive agonists KCl, U46619 and PDBu in isolated human mesenteric arteries. The influence of gender, vessel diameter and age of the patients was also investigated. Human mesenteric arteries (n = 76) were loaded in a wire myograph and maintained at a tension equivalent to the in vivo pressure of 100 mm Hg, bubbled with 95%O2/5%CO2 to maintain pH 7.4 in physiological saline solution (PSS). Cumulative concentration-response curves were obtained to KCl (100 microM-100 mM), U46619 (1 nM-1 microM) or PDBu (1 nM-1 microM), before or after a 30 min incubation with either the voltage-gated calcium channel (VGCC) blocker nifedipine (10 microM), the store-operated calcium channel (SOCC) blocker SK&F96365 (50 microM) or in calcium-free PSS (-Ca2+ PSS). The KCl response was abolished in -Ca2+ PSS and with nifedipine. The U46619 response was partially blocked in -Ca2+ PSS and with nifedipine and predominantly blocked by SK&F96365. Incubation in -Ca2+ PSS had no effect on the response to PDBu. Arteries from male patients responded significantly higher to KCl than arteries from female patients. This study demonstrates that KCl induces mesenteric vasoconstriction via activation of VGCCs, U46619 induces mesenteric vasoconstriction via activation of SOCCs, but also VGCCs and PDBu induce mesenteric vasoconstriction via a calcium-independent pathway.


Assuntos
Artérias Mesentéricas/efeitos dos fármacos , Vasoconstrição , Vasoconstritores/farmacologia , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacologia , Idoso , Cálcio/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Canais de Cálcio/metabolismo , Relação Dose-Resposta a Droga , Feminino , Humanos , Imidazóis/farmacologia , Técnicas In Vitro , Masculino , Artérias Mesentéricas/metabolismo , Pessoa de Meia-Idade , Nifedipino/farmacologia , Dibutirato de 12,13-Forbol/farmacologia , Cloreto de Potássio/farmacologia , Fatores Sexuais
12.
BMC Cardiovasc Disord ; 6: 46, 2006 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-17137495

RESUMO

BACKGROUND: Testosterone deficiency is a common occurrence in men with chronic heart failure (CHF) and may underpin features of advanced disease, including reduced skeletal muscle mass and fatigue. It is positively correlated with cardiac output and exercise capacity in patients with CHF, whereas a significant improvement in both these parameters has been observed following testosterone replacement therapy. Testosterone therapy has also been shown to reduce circulating levels of inflammatory markers, (TNF-alpha, sICAM-1 and sVCAM-1) in patients with established coronary artery disease and testosterone deficiency. This pilot study will assess the feasibility of a combined exercise rehabilitation and adjunctive testosterone therapy intervention for evoking improvements in exercise capacity, circulating inflammatory markers, cardiac and skeletal muscle function, indices of psychological health status and quality of life in hypogonadal males with chronic heart failure. METHODS/DESIGN: Following ethical approval, 36 patients will be randomly allocated to one of two groups: testosterone or placebo therapy during exercise rehabilitation. A combined programme of moderate intensity aerobic exercise and resistance (strength) training will be used. The primary outcome measure is exercise capacity, assessed using an incremental shuttle walk test. Secondary outcome measures include measures of peak oxygen uptake, cardiac function, lower-limb skeletal muscle contractile function and oxygenation during exercise, circulating inflammatory markers, psychological health status and quality of life. DISCUSSION: Exercise rehabilitation can safely increase exercise capacity in stable CHF patients but there is a need for studies which are aimed at evaluating the long-term effects of physical training on functional status, morbidity and mortality. This pilot study will provide valuable preliminary data on the efficacy of testosterone therapy as an adjunct to exercise rehabilitation on a range of functional, physiological and health-related outcomes in this patient population. Preliminary data will be used in the design of a large-scale randomised controlled trial, aimed at informing clinical practice with respect to optimisation of exercise rehabilitation in this patient group.


Assuntos
Protocolos Clínicos , Insuficiência Cardíaca/epidemiologia , Hipogonadismo/tratamento farmacológico , Testosterona/uso terapêutico , Moléculas de Adesão Celular/sangue , Terapia Combinada , Comorbidade , Teste de Esforço , Terapia por Exercício , Tolerância ao Exercício , Nível de Saúde , Humanos , Hipogonadismo/epidemiologia , Mediadores da Inflamação/sangue , Masculino , Resistência Física , Projetos Piloto , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto
13.
Endocrine ; 54(2): 504-515, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27488580

RESUMO

Testosterone deficiency is commonly associated with obesity, metabolic syndrome, type 2 diabetes and their clinical consequences-hepatic steatosis and atherosclerosis. The testicular feminised mouse (non-functional androgen receptor and low testosterone) develops fatty liver and aortic lipid streaks on a high-fat diet, whereas androgen-replete XY littermate controls do not. Testosterone treatment ameliorates these effects, although the underlying mechanisms remain unknown. We compared the influence of testosterone on the expression of regulatory targets of glucose, cholesterol and lipid metabolism in muscle, liver, abdominal subcutaneous and visceral adipose tissue. Testicular feminised mice displayed significantly reduced GLUT4 in muscle and glycolytic enzymes in muscle, liver and abdominal subcutaneous but not visceral adipose tissue. Lipoprotein lipase required for fatty acid uptake was only reduced in subcutaneous adipose tissue; enzymes of fatty acid synthesis were increased in liver and subcutaneous tissue. Stearoyl-CoA desaturase-1 that catalyses oleic acid synthesis and is associated with insulin resistance was increased in visceral adipose tissue and cholesterol efflux components (ABCA1, apoE) were decreased in subcutaneous and liver tissue. Master regulator nuclear receptors involved in metabolism-Liver X receptor expression was suppressed in all tissues except visceral adipose tissue, whereas PPARγ was lower in abdominal subcutaneous and visceral adipose tissue and PPARα only in abdominal subcutaneous. Testosterone treatment improved the expression (androgen receptor independent) of some targets but not all. These exploratory data suggest that androgen deficiency may reduce the buffering capability for glucose uptake and utilisation in abdominal subcutaneous and muscle and fatty acids in abdominal subcutaneous. This would lead to an overspill and uptake of excess glucose and triglycerides into visceral adipose tissue, liver and arterial walls.


Assuntos
Tecido Adiposo/efeitos dos fármacos , Glucose/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Testosterona/farmacologia , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Tecido Adiposo/metabolismo , Animais , Apolipoproteínas E/metabolismo , Dieta Hiperlipídica , Fígado/metabolismo , Masculino , Camundongos , Músculo Esquelético/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Testosterona/sangue
14.
Am J Cardiovasc Drugs ; 5(3): 141-54, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15901202

RESUMO

Two of the strongest independent risk factors for coronary heart disease (CHD) are increasing age and male sex. Despite a wide variance in CHD mortality between countries, men are consistently twice as likely to die from CHD than their female counterparts. This sex difference has been attributed to a protective effect of female sex hormones, and a deleterious effect of male sex hormones, upon the cardiovascular system. However, little evidence suggests that testosterone exerts cardiovascular harm. In fact, serum levels of testosterone decline with age, and low testosterone is positively associated with other cardiovascular risk factors. Furthermore, testosterone exhibits a number of potential cardioprotective actions. For example, testosterone treatment is reported to reduce serum levels of the pro-inflammatory cytokines interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha, and to increase levels of the anti-inflammatory cytokine IL-10; to reduce vascular cell adhesion molecule (VCAM)-1 expression in aortic endothelial cells; to promote vascular smooth muscle and endothelial cell proliferation; to induce vasodilatation and to improve vascular reactivity, to reduce serum levels of the pro-thrombotic factors plasminogen activator inhibitor (PAI)-1 and fibrinogen; to reduce low-density lipoprotein-cholesterol (LDL-C); to improve insulin sensitivity; and to reduce body mass index and visceral fat mass. These actions of testosterone may confer cardiovascular benefit since testosterone therapy reduces atheroma formation in cholesterol-fed animal models, and reduces myocardial ischemia in men with CHD. Consequently, an alternative hypothesis is that an age-related decline in testosterone contributes to the atherosclerotic process. This is supported by recent findings, which suggest that as many as one in four men with CHD have serum levels of testosterone within the clinically hypogonadal range. Consequently, restoration of serum levels of testosterone via testosterone replacement therapy could offer cardiovascular, as well as other, clinical advantages to these individuals.


Assuntos
Envelhecimento/sangue , Arteriosclerose/sangue , Testosterona/sangue , Animais , Arteriosclerose/tratamento farmacológico , LDL-Colesterol/sangue , Citocinas/sangue , Humanos , Masculino , Modelos Biológicos , Testosterona/uso terapêutico
16.
J Clin Endocrinol Metab ; 89(7): 3313-8, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15240608

RESUMO

Testosterone has immune-modulating properties, and current in vitro evidence suggests that testosterone may suppress the expression of the proinflammatory cytokines TNFalpha, IL-1beta, and IL-6 and potentiate the expression of the antiinflammatory cytokine IL-10. We report a randomized, single-blind, placebo-controlled, crossover study of testosterone replacement (Sustanon 100) vs. placebo in 27 men (age, 62 +/- 9 yr) with symptomatic androgen deficiency (total testosterone, 4.4 +/- 1.2 nmol/liter; bioavailable testosterone, 2.4 +/- 1.1 nmol/liter). Compared with placebo, testosterone induced reductions in TNFalpha (-3.1 +/- 8.3 vs. 1.3 +/- 5.2 pg/ml; P = 0.01) and IL-1beta (-0.14 +/- 0.32 vs. 0.18 +/- 0.55 pg/ml; P = 0.08) and an increase in IL-10 (0.33 +/- 1.8 vs. -1.1 +/- 3.0 pg/ml; P = 0.01); the reductions of TNFalpha and IL-1beta were positively correlated (r(S) = 0.588; P = 0.003). In addition, a significant reduction in total cholesterol was recorded with testosterone therapy (-0.25 +/- 0.4 vs. -0.004 +/- 0.4 mmol/liter; P = 0.04). In conclusion, testosterone replacement shifts the cytokine balance to a state of reduced inflammation and lowers total cholesterol. Twenty of these men had established coronary disease, and because total cholesterol is a cardiovascular risk factor, and proinflammatory cytokines mediate the development and complications associated with atheromatous plaque, these properties may have particular relevance in men with overt vascular disease.


Assuntos
Citocinas/sangue , Terapia de Reposição Hormonal , Hipogonadismo/tratamento farmacológico , Mediadores da Inflamação/sangue , Lipídeos/sangue , Testosterona/uso terapêutico , Adulto , Idoso , Colesterol/sangue , LDL-Colesterol/sangue , Estudos Cross-Over , Humanos , Hipogonadismo/sangue , Interleucina-1/sangue , Interleucina-10/sangue , Masculino , Pessoa de Meia-Idade , Método Simples-Cego , Fator de Necrose Tumoral alfa/metabolismo
17.
Am J Cardiol ; 92(10): 1241-3, 2003 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-14609611

RESUMO

The effects of testosterone on cardiac electrophysiology are poorly described. In this study we report the effect of physiologic testosterone therapy in 2 cohorts of men, the first with stable coronary disease and the second with congestive heart failure. Testosterone reduced QT dispersion in the heart failure cohort; no other effects were observed.


Assuntos
Androgênios/farmacologia , Doença das Coronárias/fisiopatologia , Eletrocardiografia/efeitos dos fármacos , Insuficiência Cardíaca/fisiopatologia , Terapia de Reposição Hormonal , Testosterona/farmacologia , Administração Cutânea , Idoso , Estudos de Coortes , Método Duplo-Cego , Humanos , Injeções Intramusculares , Masculino , Pessoa de Meia-Idade
18.
Eur J Endocrinol ; 151(1): 29-37, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15248819

RESUMO

Recent clinical studies have reported that testosterone therapy reduces myocardial ischaemia in men with coronary artery disease, and the beneficial modulation of coronary vascular tone by testosterone has been proposed as an effector mechanism. Maintenance of a correct response to vasoconstrictive and vasodilatory agents is essential in the control of vascular tone. Endothelial dysfunction, most commonly manifested through an elevation in vascular tone, is implicated as an initiating factor in conditions such as hypertension and atherosclerosis. Increased sensitivity to vasoconstrictive stimuli is also proposed in the development of heart failure and hypertensive vascular remodelling, while increased coronary vascular reactivity to vasoconstrictive factors is likely further to restrict coronary blood flow through the partially occluded atherosclerotic vessel. Reduced vasodilatation and enhanced vasoconstriction can also lead to vasospasm and exacerbation of anginal symptoms. Testosterone is well known to elicit direct vasodilatation, but its influence upon responses induced by other vasoactive agents is less coherent, and may depend upon the underlying pathogenic process or gender. The aim of this review is to present the data obtained from both the patient and animal studies conducted to date, to ascertain any influence testosterone may have upon the regulation of vascular tone.


Assuntos
Androgênios/fisiologia , Testosterona/fisiologia , Vasoconstrição/fisiologia , Vasodilatação/fisiologia , Androgênios/farmacologia , Animais , Circulação Coronária/efeitos dos fármacos , Circulação Coronária/fisiologia , Humanos , Testosterona/farmacologia , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos
19.
Eur J Endocrinol ; 148(1): 111-20, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12534364

RESUMO

OBJECTIVE: Testicular feminised (Tfm) mice express a non-functional androgen receptor, and also have reduced levels of circulating testosterone. Recent studies support a cardio-protective role for testosterone since it elicits systemic and pulmonary vasodilatation. The aim of the present study was to determine whether androgen insensitivity and hypotestosteronaemia in the Tfm mouse are associated with abnormal vascular reactivity or hormone status. METHODS: Adult male Tfm and littermate control mice were killed and the blood collected. Femoral (diameter range = 183-508 microm) and pulmonary (diameter range = 320-816 microm) arteries were dissected and loaded in either a wire or pressure myograph, at 100 mmHg or 17.5 mmHg respectively. Pharmacological assessment of the vasoreactivity to potassium chloride (KCl, 80 mmol/l) and either noradrenaline (NA, 1 nmol/l-100 micromol/l) and acetylcholine (ACh, 0.1-100 micromol/l) or testosterone (1 nmol/l-100 micromol/l) was then made. RESULTS: Tfm mice had reduced levels of testosterone (1.8+/-0.3 nmol/l) compared with controls (9.3+/-2.0 nmol/l, P<0.001) and elevated levels of cholesterol (3.6+0.1 mmol/l) compared with controls (3.2+0.1 mmol/l, P<0.05). Femoral arteries from Tfm mice exhibited reduced vasoconstriction to 80 mmol/l KCl (3.27+/-0.23 mN/mm) compared with vessels from controls (4.44+/-0.41 mN/mm, P<0.05), and reduced endothelial-dependent vasodilatation to 0.1-100 micromol/l ACh (23.3+/-3.6% relaxation) compared with vessels from controls (41.6+/-5.4% relaxation, P<0.05). Vasoconstriction to NA (1 nmol/l-100 micromol/l) and vasodilatation to testosterone were unaffected. CONCLUSIONS: Androgen receptor deficiency and hypotestosteronaemia in the Tfm mouse reduced endothelial function and impaired voltage-operated calcium channel activity, which may pre-dispose to cardiovascular disease. Testosterone-induced vasodilatation was unaffected, demonstrating no involvement of the androgen receptor in this response.


Assuntos
Síndrome de Resistência a Andrógenos/sangue , Endotélio Vascular/fisiologia , Testosterona/sangue , Testosterona/deficiência , Vasodilatação/fisiologia , Animais , Doenças Cardiovasculares/sangue , Complacência (Medida de Distensibilidade) , Modelos Animais de Doenças , Artéria Femoral/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Miografia , Pressão
20.
Eur J Endocrinol ; 151(2): 241-9, 2004 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15296480

RESUMO

OBJECTIVE: In the absence of widely available measures of determining free and/or bioavailable testosterone (BioT) physicians may use formulae such as the free androgen index (FAI) to estimate free testosterone. We compared the efficacy of calculated markers of androgen status in predicting serum BioT and hypogonadism. DESIGN: Total testosterone (TT), sex hormone binding globulin (SHBG) and BioT were determined in a large cohort of men. Comparison of calculated androgen levels was performed following endocrine assessment. METHODS: TT and SHBG were determined by ELISA, and BioT was determined by ammonium sulphate precipitation. From these data we calculated FAI and free testosterone using two other published formulae - FTnw (free testosterone as calculated by the method of Nanjeee and Wheeler) and FTv (free testosterone as calculated by the method of Vermeulen). A novel formula was derived to calculate BioT from given levels of TT and SHBG (BTcalculated). The ability of the methods (FAI, FTnw, FTv, BTcalc) to predict BioT were compared using regression analysis. The ability of these markers of androgen status to predict biochemical hypogonadism was compared using area under receiver operator curve (auROC). RESULTS: The equation derived from our data was the best predictor of BioT (R(2)=0.73, P<0.0001) although TT was also a good marker (R(2)=0.68, P=0.0001). In the determination of hypogonadism, of all currently available formulae none were better that the TT (auROC: TT=0.93, FAI=0.72, FTnw=0.91, FTv=0.88) although when TT is borderline (7.5

Assuntos
Hipogonadismo/sangue , Hipogonadismo/diagnóstico , Modelos Biológicos , Testosterona/sangue , Biomarcadores/sangue , Estudos de Coortes , Humanos , Masculino , Valor Preditivo dos Testes , Análise de Regressão , Sensibilidade e Especificidade , Globulina de Ligação a Hormônio Sexual/metabolismo
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