Testosterone and other anabolic steroids as cardiovascular drugs

Testosterone and Cardiovascular Disease

Cardiovascular disease [CVD] is a leading cause of mortality accounting for a global incidence of over 31%. Atherosclerosis is the primary pathophysiology underpinning most types of CVD. Historically, modifiable and non-modifiable risk factors were suggested to precipitate CVD. Recently, epidemiological studies have identified emerging risk factors including hypotestosteronaemia, which have been associated with CVD. Previously considered in the realms of reproductive biology, testosterone is now believed to play a critical role in the cardiovascular system in health and disease. The actions of testosterone as they relate to the cardiac vasculature and its implication in cardiovascular pathology is reviewed.

Doping with anabolic androgenic steroids (AAS): Adverse effects on non-reproductive organs and functions

Since the 1970s anabolic androgenic steroids (AAS) have been abused at ever increasing rates in competitive athletics, in recreational sports and in bodybuilding. Exceedingly high doses are often consumed over long periods, in particular by bodybuilders, causing acute or chronic adverse side effects frequently complicated by additional polypharmacy. This review summarizes side effects on non-reproductive organs and functions; effects on male and female reproduction have been recently reviewed in a parallel paper. Among the most striking AAS side effects are increases in haematocrit and coagulation causing thromboembolism, intracardiac thrombosis and stroke as well as other cardiac disturbances including arrhythmias, cardiomyopathies and possibly sudden death. 17α-alkylated AAS are liver toxic leading to cholestasis, peliosis, adenomas and carcinomas. Hyperbilirubinaemia can cause cholemic nephrosis and kidney failure. AAS abuse may induce exaggerated self-confidence, reckless behavior, aggressiveness and psychotic symptoms. AAS withdrawal may be accompanied by depression and suicidal intentions. Since AAS abuse is not or only reluctantly admitted physicians should be aware of the multitude of serious side effects when confronted with unclear symptoms.

Effects of testosterone on norepinephrine release in isolated rat heart

The effects of testosterone on norepinephrine release were investigated in the isolated rat hearts. Sprague-Dawley male rats (n=120) were randomized to testosterone and control groups. The rats in testosterone group were perfused with modified Krebs-Henseleit buffer containing different concentrations of testosterone (0.1, 1.0, 10.0, and 100.0 nmol/L, respectively). Myocardial ischemia was induced by globally stopping the perfusion flow. Exocytotic norepinephrine release was induced by electrical field stimulation at 5 V (effective voltage) and 6 Hz (pulse width of 2 ms) for 1 min. The overflow of norepinephrine was determined by high pressure liquid chromatography and electrochemical detection (HPLC-EC). Following acute ischemia, testosterone (1.0, 10.0 and 100.0 nmol/L) significantly reduced norepinephrine release (P<0.01), and the norepinepherine overflow was similar between the control and 0.1 nmol/L testosterone group (P>0.05). Electrical stimulation of the ventricle evoked norepinepherine release, and this was diminished by the perfusion with testosterone at the concentrations of 1.0, 10.0 and 100.0 nmol/L (P<0.01). It is suggested that testosterone suppresses ischemia- and electrical stimulation-induced norepinepherine release in the isolated rat hearts.

Structural and functional changes of peripheral muscles in chronic obstructive pulmonary disease patients

PURPOSE OF REVIEW

The purpose of this review is to identify new advances in our understanding of skeletal muscle dysfunction in patients with chronic obstructive pulmonary disease (COPD).

RECENT FINDINGS

Recent studies have confirmed the relevance of muscle dysfunction as an independent prognosis factor in COPD. Animal studies have shed light on the molecular mechanisms governing skeletal muscle hypertrophy/atrophy. Recent evidence in patients with COPD highlighted the contribution of protein breakdown and mitochondrial dysfunction as pathogenic mechanisms leading to muscle dysfunction in these patients.

SUMMARY

COPD is a debilitating disease impacting negatively on health status and the functional capacity of patients. COPD goes beyond the lungs and incurs significant systemic effects among which muscle dysfunction/wasting is one of the most important. Muscle dysfunction is a prominent contributor to exercise limitation, healthcare utilization and an independent predictor of morbidity and mortality. Gaining more insight into the molecular mechanisms leading to muscle dysfunction/wasting is key for the development of new and tailored therapeutic strategies to tackle skeletal muscle dysfunction/wasting in COPD patients.

Sex differences in the fetal programming of hypertension

BACKGROUND

Numerous clinical and experimental studies support the hypothesis that the intrauterine environment is an important determinant of cardiovascular disease and hypertension.

OBJECTIVE

This review examined the mechanisms linking an adverse fetal environment and increased risk for chronic disease in adulthood with an emphasis on gender differences and the role of sex hormones in mediating sexual dimorphism in response to a suboptimal fetal environment.

METHODS

This review focuses on current findings from the PubMed database regarding animal models of fetal programming of hypertension, sex differences in phenotypic outcomes, and potential mechanisms in offspring of mothers exposed to an adverse insult during gestation. For the years 1988 to 2007, the database was searched using the following terms: fetal programming, intrauterine growth restriction, low birth weight, sex differences, estradiol, testosterone, high blood pressure, and hypertension.

RESULTS

The mechanisms involved in the fetal programming of adult disease are multifactorial and include alterations in the regulatory systems affecting the long-tterm control of arterial pressure. Sex differences have been observed in animal models of fetal programming, and recent studies suggest that sex hormones may modulate activity of regulatory systems, leading to a lower incidence of hypertension and vascular dysfunction in females compared with males.

CONCLUSIONS

Animal models of fetal programming provide critical support for the inverse relationship between birth weight and blood pressure. Experimental models demonstrate that sex differences are observed in the pathophysiologic response to an adverse fetal environment. A role for sex hormone involvement is strongly suggested,with modulation of the renin-angiotensin system as a possible mechanism.

Effects of oxandrolone, an anabolic steroid, on hemostasis

This study evaluated the short-term effects of oxandrolone, an anabolic androgenic synthetic steroid, on blood coagulation and the hemostatic/fibrinolytic system in healthy individuals. Subjects (n = 14) were administered oxandrolone (10 mg twice daily) for 14 days. Blood was obtained on days 0, 1, 3, 7, 9, 14, and then at day 42 (28 days after discontinuation of the drug). Samples were analyzed for the plasma plasminogen, plasminogen activator inhibitor (PAI-1), fibrinogen, and coagulation factors (II, V, VII, VIII, and X). After 7 days of administration of oxandrolone, the plasma plasminogen level significantly increased [100% +/- 21% to 174% +/- 21% (P < 0.0001)]. PAI-1 was significantly decreased at day 3 [16 +/- 9 to 7 +/- 4 mg/dL (P < 0.01)]. Coagulation factors II and V significantly increased at day 14 [88 +/- 15 to 122 +/- 11 (P < 0.005) and 105 +/- 21 to 179 +/- 36% (P < 0.0001)], respectively. Factor VII level decreased by day 3 [91% +/- 26% to 83% +/- 18%, NS], but after 14 days factor VII level returned to baseline (91% +/- 26% to 93% +/- 19%, NS). The increase of factor VIII level was not significant (111% +/- 64% to 125% +/- 55%, NS). Factor X increased steadily over 14 days of drug treatment [96% +/- 11% to 107% +/- 25%, NS] and after discontinuation, decreased and returned to baseline by day 42 [107% +/- 25% to 89% +/- 25%, NS]. Fibrinogen decreased by 22% +/- 12%, (NS). Administration of oxandrolone, to healthy young men was associated with a significant increase in select blood coagulation factors and plasminogen. These changes create a state of potential hypercoagulability that appears to be counterbalanced by increased fibrinolytic activity to maintain homeostasis.

Relationship between androgenic hormones and arterial stiffness, based on longitudinal hormone measurements

Circulating testosterone levels (T) decrease with age in men. Low T has been associated with coronary disease and with risk factors for atherosclerosis. This study examines the relationship in men between androgenic hormones and arterial stiffness, a major risk factor for cardiovascular events. T, sex hormone-binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEAS) were measured longitudinally over 33 yr (follow-up 11.8 +/- 8.3 yr) in 901 men from the Baltimore Longitudinal Study of Aging, of whom 206 (68.1 +/- 13.7 yr) underwent carotid duplex ultrasonography. The 901 men were used to characterize age-associated hormone levels by means of mixed-effects models. Hormone values were estimated for the 206 men at the time of ultrasonography. Free T index (FTI) was calculated by dividing T by SHBG. The arterial stiffness index was calculated from peak systolic and end diastolic diameters of the common carotid artery and simultaneous brachial artery blood pressure. T, FTI, and DHEAS were correlated negatively with age, pulse pressure (PP), and stiffness index (each P < 0.01), whereas SHBG was correlated positively with age and stiffness index (P < 0.01). However, T was the only hormone that predicted the stiffness index after adjustment for age, PP, fasting plasma glucose, body mass index, and total cholesterol. T values 5-10 yr before the carotid study also predicted the stiffness index (P < 0.05). Thus the adverse influence of low T on the cardiovascular system in men may be mediated in part via the effects of T on vascular structure and function.

The aging male: testosterone deficiency and testosterone replacement. An up-date

The significance of the age-related decline of androgens remains unclear in terms of cardiovascular risk, mood and cognition, and prostatic health. Although much research has been undertaken in this area and men's health has received still more attention in the latest years, there are no data based on randomized controlled clinical studies in aging men investigating the long-term effects of androgen replacement therapy on various aspects of the cardiovascular system, the immune system, body composition, and the brain. In men receiving long-term androgen replacement therapy, the safety aspects regarding the prostate are also an area of clinical importance. In this paper we present an up-dated review of the experimental and clinical evidence of androgen deficiency and androgen replacement therapy on carbohydrate metabolism, on coagulation and fibrinolysis, inflammatory effects, effects on lipoprotein metabolism, direct arterial effects, effects on body composition, effects on cognitive function and mood, and prostatic effects. The evidence clearly shows that data for the most part are conflicting, with only very few randomized studies available.

Sex-specific changes in platelet aggregation and secretion with sexual maturity in pigs

Cardiovascular disease may begin early in adolescence. Platelets release factors contributing to vascular disease. Experiments were designed to test the hypothesis that hormonal transitions associated with sexual maturity differentially affect platelet aggregation and secretion in males and females. Platelets were collected from juvenile (2-3 mo) and sexually mature (adult; 5-6 mo) male and female pigs (n=8/group). Maturation was evidenced by increased weight of reproductive tissue and changes in circulating levels of gonadal hormones. Aggregation to ADP (10 microM) and collagen (6 microg/ml) and ATP secretion to 50 nM thrombin were determined by turbidimetric analysis and bioluminescence, respectively. Total platelet counts, platelet turnover, and mean platelet volume did not change with maturity. Platelet aggregation and ATP secretion decreased in females but increased in males with maturity, whereas total ATP content remained unchanged in platelets from females but increased in platelets from males. Platelet fibrinogen receptor, P-selectin expression, and receptors for sex steroids did not change with sexual maturation. Plasma C-reactive protein and brain-type natriuretic peptide also did not change. Results indicate that changes in platelet aggregation and secretion change with sexual maturity differently in females and males. These observations provide evidence on which clinical studies could be designed to examine platelet characteristics in human children and young adults.

Cœur et androgènes

Beyond regulation of sexual function, male steroids play an important role in many physiological homeostasis systems, including the cardiovascular system. Via a specific androgen receptor, testosterone mediates cardiomyocyte trophicity both in physiological situations and in hypertrophy-related cardiac diseases. Androgens also regulate pathological levels of inflammatory cytokines such as Il-6 or TNF in advanced heart failure. They also mediate vascular resistance since coronary vasodilatation has been proven both in vitro and in vivo. Reduced free testosterone serum levels (age-mediated or premature coronary artery disease) promote a pro-atherogenic lipid profile expressed as lower serum HDL-cholesterol and up-regulation of triglyceride levels. This observation has relevant clinical implications for the evaluation and treatment of coronary artery disease. As most of normal and diseased cardiovascular system functions are influenced by androgens, further evaluation of their physiological implications should be undertaken as well as large-scale rigorous studies of the therapeutic implications in two disabling diseases, coronary heart disease and heart failure.

Effect of testosterone therapy on QT dispersion in men with heart failure

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.

Endothelium-dependent responses in coronary arteries are changed with puberty in male pigs

In humans, cardiovascular disease begins in young adulthood and is more prevalent in males than females. However, little is known about vascular function during transition to adulthood in males. The aim of this study was to define changes in production of endothelium-derived nitric oxide (NO) and coronary arterial responses during puberty. Plasma was collected from juvenile (2-3 mo of age) and adult (5-6 mo of age) male pigs (n = 8/group) for measurement of NO, and aortic endothelial cells were collected for measurement of mRNA and protein for endothelial NO synthase (eNOS). Although plasma NO was higher in juvenile (67.0 +/- 25.6 microM) than in adult (15.0 +/- 7.1 microM) male pigs, eNOS protein was similar in both groups. However, levels of mRNA for eNOS were lower in aortic endothelial cells from juvenile pigs. In rings of coronary arteries suspended in organ chambers for measurement of isometric force and contracted with PGF2alpha, relaxations to an alpha2-adrenergic agonist were significantly inhibited by indomethacin only in juvenile pigs [EC50 (-log M), 6.7 +/- 0.3 with indomethacin and 7.7 +/- 0.3 under control conditions]. NG-monomethyl-l-arginine (l-NMMA) inhibited relaxations in both groups. On the contrary, in the presence of indomethacin, relaxations to bradykinin were inhibited by l-NMMA only in arteries from adult pigs [EC50 (-log M), 8.9 +/- 0.3 with indomethacin and 8.6 +/- 0.3 with addition of l-NMMA]. These results suggest that hormonal changes associated with sexual maturity may affect posttranscriptional and/or translational regulation of eNOS protein and result in lower plasma NO in adult male pigs. In addition, endothelium-derived inhibitory cyclooxygenase products seem to predominate in juveniles.

Cardiovascular effects of androgens

In the process of atherosclerosis sex steroids play a complex role in the vascular vessel wall system. Although a number of experimental studies have clearly documented an atheroprotective effect of estrogens, in recent clinical studies, estrogen replacement therapy has failed to reduce cardiovascular mortality. The effects of androgens on the cardiovascular system and cardiovascular diseases are even more controversial. Whereas in the past, androgens were mainly believed to exert adverse effects on the cardiovascular system, recent studies in men have documented a number of beneficial actions of testosterone in the arterial vascular system. Androgens affect lipid metabolism (e.g., LDL and HDL cholesterol, Lp(a)) and hemostasis (e.g., platelet aggregation and fibrinolytic activity). In addition, several other physiological and pathophysiological processes in the arterial vessel wall are influenced by androgens. Acute hemodynamic effects of testosterone on coronary vasomotion and stress-test-induced ischemia were reported. Additionally, recent animal and in vitro studies have further documented an inhibitory effect of androgens on neointimal plaque formation. This review discusses different and, in part, contradictory effects of androgens on the cardiovascular system including potential signal transduction pathways in androgen target cells.

The effect of testosterone on regional blood flow in prepubertal anaesthetized pigs

This work was undertaken to study the effects of testosterone on the coronary, mesenteric, renal and iliac circulations and to determine the mechanisms of action involved. In prepubertal pigs of both sexes anaesthetized with sodium pentobarbitone, changes in left circumflex or anterior descending coronary, superior mesenteric, left renal and left external iliac blood flow caused by intra-arterial infusion of testosterone were assessed using electromagnetic flowmeters. Changes in heart rate and arterial blood pressure were prevented by atrial pacing and by connecting the arterial system to a pressurized reservoir containing Ringer solution. In 12 pigs, intra-arterial infusion of testosterone for 5 min to achieve a stable intra-arterial concentration of 1 microg l(-1) increased coronary, mesenteric, renal and iliac blood flow without affecting the maximum rate of change of left ventricular systolic pressure (left ventricular dP/dt(max)) and filling pressures of the heart. In a further five pigs, a concentration-response curve was obtained by graded increases in the intra-arterial concentration of the hormone between 0.125 and 8 microg l(-1). The mechanisms of these responses were studied in the 12 pigs by repeating the experiment after haemodynamic variables had returned to the control values before infusions. In six pigs, blockade of muscarinic cholinoceptors and adrenoceptors with atropine, propranolol and phentolamine did not affect the responses caused by intra-arterial infusion of testosterone performed to achieve a stable intra-arterial concentration of 1 microg l(-1). In the same pigs and in the remaining six pigs, the increases in coronary, mesenteric, renal and iliac blood flow caused by intra-arterial infusion of testosterone performed to achieve a stable intra-arterial concentration of 1 microg l(-1) were prevented by intra-arterial injection of N(omega)-nitro-L-arginine methyl ester. The present study shows that intra-arterial infusion of testosterone dilated coronary, mesenteric, renal and iliac circulations. The mechanism of this response involved the release of nitric oxide.

Interrelationships among lipoprotein levels, sex hormones, anthropometric parameters, and age in hypogonadal men treated for 1 year with a permeation-enhanced testosterone transdermal system

Serum lipoproteins and cardiovascular risk are affected by endogenous and exogenous sex hormones. As part of a multicenter evaluation of a permeation-enhanced testosterone transdermal system (TTD), the interrelationships among serum lipoproteins, hormone levels, anthropometric parameters, and age were investigated in 29 hypogonadal men. Subjects (aged 21-65 yr) were first studied during prior treatment with im testosterone esters (IM-T), then during an 8-week period of androgen withdrawal resulting in a hypogonadal state (HG), and finally during a 1-yr treatment period with the TTD. Compared with treatment with IM-T, the HG period produced increases in high density lipoprotein [HDL; 12.0 +/- 1.6% (+/-SEM); P<0.001] and total cholesterol (4.2 +/- 1.9%; P: = 0.02) and a decrease in the cholesterol/HDL ratio (-9.7 +/- 2.8%; P = 0.02). Compared with the HG period, TTD treatment produced decreases in HDL (-7.6 +/- 2.5%; P = 0.002) and increases in the cholesterol/HDL ratio (9.0 +/- 2.5%; P = 0.01) and triglycerides (20.7 +/- 6.4%; P: = 0.03). Small decreases in total cholesterol (-1.2 +/- 1.8%; P: = 0.1) and low density lipoprotein (-0.8 +/- 2.6%; P = 0.07) were also observed during TTD, but did not reach statistical significance. Likewise, there were no significant differences between the IM-T and TTD treatments. Serum HDL levels showed a strong negative correlation with body mass index and other obesity parameters in all three study periods (r < -0.45; P < 0.02). During treatment with TTD, serum testosterone levels also correlated negatively with body mass index (r = -0.621; P < 0.001). As a consequence of these relationships, a positive trend was observed between HDL and testosterone levels during TTD treatment (r = 0.336; P = 0.07). Interestingly, the changes in lipoprotein levels during TTD treatment indicated a more favorable profile (decrease in cholesterol and low density lipoprotein levels) with increasing age of the patients. In hypogonadal men the effects of transdermal testosterone replacement on serum lipoproteins appear consistent with the physiological effects of testosterone in eugonadal men.