Nandrolone-pretreatment enhances cardiac beta(2)-adrenoceptor expression and reverses heart contractile down-regulation in the post-stress period of acute-stressed rats

Mitochondrial dysfunction and cardiac ischemia/reperfusion injury are attenuated by nandrolone: Role of JAK-STAT3 pathway

AIM

To investigate the effect of acute treatment with the anabolic steroid (AS) nandrolone decanoate in mitochondrial homeostasis and JAK-STAT3 signaling during the progression of cardiac ischemia/reperfusion injury (IR).

METHODS

Male Wistar rats (2 months old) were randomly allocated into four experimental groups: Control (CTRL), IR, AS, and AS+AG490. All animals were euthanized 3 days after a single intramuscular injection of nandrolone at 10 mg/kg (AS and AS+AG490 groups) or vehicle (CTRL and IR groups). Baseline mRNA expression of antioxidant enzymes superoxide dismutase (SOD) 1 and 2, glutathione peroxidase, catalase, and myosin heavy chain (MHC) α and β were compared between CTRL and AS groups. Isolated hearts were submitted to ex vivo ischemia and reperfusion, except for hearts from the CTRL group. Before the IR protocol, the JAK-STAT3 inhibitor AG490 was perfused in hearts from the AS+AG490 group. Heart samples were collected during reperfusion to investigate the effects on mitochondrial function. Results Antioxidant enzyme mRNA expression was unaffected, whereas the AS group exhibited decreased β- MHC/α-MHC ratio versus the CTRL group. Compared to the IR group, the AS group exhibited better recovery of post-ischemic left ventricular (LV) end-diastolic pressure and LV-developed pressure levels, while infarct size significantly decreased. Furthermore, mitochondrial production, transmembrane potential, and swelling were improved, whereas ROS formation was decreased versus the IR group. These effects were prevented by the perfusion of JAK-STAT3 inhibitor AG490.

CONCLUSION

These findings suggest that acute nandrolone treatment can provide cardioprotection by recruiting the JAK-STAT3 signaling pathway and mitochondrial preservation.

Nandrolone Decanoate and Swimming Affects Cardiodynamic and Morphometric Parameters in the Isolated Rat Heart

(1) Background: The aim of this study was to show the effects of swimming and nandrolone administration on cardiodynamic and morphometric parameters of the isolated rat heart. (2) The study included 72 Wistar rats, divided into three groups, scheduled to be sacrificed after the second, third, and fourth week. Each group was divided into four subgroups: control (T-N-), nandrolone (T-N+), swimming training (T+N-), and swimming training plus nandrolone (T+N+) group. The rats from T+N- and T+N+ swam 1 h/day, 5 days/week while ones from T-N+ and T+N+ received weekly nandrolone decanoate (20 mg/kg). The isolated hearts were perfused according to the Langendorff technique and measured parameters: dp/dt max/min, SLVP, DLVP, heart rate, and coronary flow. Hearts were fixed and stained with H/E and Masson trichrome dyes. (3) dp/dt max and dp/dt min were increased in the T-N+ group at higher perfusion pressure compared to the T-N- group. SLVP and DLVP were increased in all groups after the 4th week. Collagen content was increased in T-N+ by 403% and in T+N+ by 357% groups, while it was decreased in T+N- compared to the control after 4th week. (4) Conclusions: Nandrolone alone or combined with swimming had a deleterious effect on myocardial function and perfusion.

Ischemic Preconditioning Efficacy Following Anabolic Steroid Usage: A Clear Difference Between Sedentary and Exercise-Trained Rat Hearts

Previous studies show that anabolic steroids impair innate cardioprotective mechanisms. Here, we investigated the effect of supraphysiological doses of nandrolone on ischemic preconditioning (IPC) as a potent cardioprotective tool against ischemia reperfusion (IR) injury in rat hearts. Male Wistar rats in two experimental settings of sedentary and exercise-trained (60 min/day swimming, 5 days/week, for 8 weeks) were either pretreated with intramuscular injections of arachis oil (Arach, n = 16) as vehicle or nandrolone decanoate (ND, n = 8), 10 mg/kg/week, for 8 weeks. At the end, the hearts were excised and perfused in a Langendorff system. Then, the vehicle-treated hearts subdivided into the IR (30 min of LAD coronary artery occlusion and 120 min reperfusion, n = 8) and IPC (three cycles of 3-min ischemia and 3-min reperfusion before test ischemia, n = 8) groups and nandrolone-treated hearts served as ND + IPC (nandrolone pretreatment before IR and IPC protocols, n = 8) group. Post-ischemic cardiac function and infarct size were assessed. Reperfusion arrhythmias were analyzed using a standard scoring system. In sedentary hearts, ND slightly increased heart-to-body weight ratio and increased baseline cardiac contractile function. In trained hearts, ND markedly increased heart-to-body weight ratio which was also associated with enhanced baseline cardiac function. ND pretreatment enhanced protective effects of IPC in sedentary group; however, abolished these effects in exercise-trained group. The arrhythmia score was not significantly different between nandrolone-treated groups vs. respective preconditioned groups. Our findings show that ND impairs IPC-induced cardioprotection in exercise-trained rat hearts. Cardiac hypertrophy seems to play a crucial role in this response.

Cardiac electrical and contractile disorders promoted by anabolic steroid overdose are associated with late autonomic imbalance and impaired Ca2+ handling

AIM

Investigate cardiac electrical and mechanical dysfunctions elicited by chronic anabolic steroid (AS) overdose.

METHODS

Male Wistar rats were treated with nandrolone decanoate (DECA) or vehicle (CTL) for 8 weeks. Electrocardiography and heart rate variability were assessed at weeks 2, 4, and 8. Cardiac reactivity to isoproterenol was investigated in isolated rat hearts. Action potential duration (APD) was measured from left ventricular (LV) muscle strips. L-type Ca²⁺ current (I_CaL), and transient outward potassium current (I_to) were recorded by whole-cell patch-clamp in LV cardiomyocytes. Sarcoplasmic reticulum (SR) Ca²⁺ mobilization and Ca²⁺-induced contractile response sensitivity were evaluated in skinned cardiac fibers. Muscarinic type 2 receptor (M₂R), β₁-adrenergic receptor (β₁AR), sarcoplasmic Ca²⁺ ATPase (SERCA-2a), type 2 ryanodine receptor (RyR2), L-type Ca²⁺ channel (CACNA1), Kv4.2 (KCND2), and Kv4.3 (KCND3) mRNA expression levels were measured by quantitative RT-PCR.

RESULTS

Compared with CTL group, DECA group exhibited decreased high frequency band power density (HF) and increased low frequency power density (LF), Cardiac M₂R mRNA level was decreased. QTc interval at 2nd, 4th, and 8th week as well as APD₃₀ and APD₉₀ were increased by DECA. I_to density was decreased, while I_CaL density was increased by DECA. SR Ca²⁺ loading and release were decreased by DECA, while contractile sensitivity to Ca²⁺ was increased versus CTL group.

CONCLUSION

DECA overdose induced cardiac rhythmic and mechanical abnormalities that can be associated with autonomic imbalance, up-regulated I_CaL and down-regulated I_to, abnormal SR Ca²⁺ mobilization, and increased contractile sensitivity to Ca²⁺.

Micturition dysfunction in four-month old ovariectomized rats: Effects of testosterone replacement

AIMS

Androgen deficiency has been implicated in urological complications of postmenopausal women. This study examined the effects of testosterone replacements on the lower urinary tract dysfunction in 4-month old ovariectomized (OVX) rats.

MAIN METHODS

Sprague-Dawley female rats were OVX bilaterally. Three months later, rats received single intramuscular injections of testosterone undecanoate. Cystometric study, and bladder and urethra smooth muscle reactivities were evaluated.

KEY FINDINGS

Ovariectomy reduced by 65% (p<0.05) the serum testosterone levels. Testosterone replacement at 5mg/kg restored serum hormone levels to baseline, whereas 10mg/kg produced 14-fold higher testosterone levels. OVX rats exhibited significant increases of body weight, perigonadal fat and blood pressure, and reduced uterus weight, but none of these parameters were changed by testosterone replacements. OVX rats exhibited micturition dysfunction characterized by increases of basal pressure, threshold pressure, voiding frequency and post-voiding pressure. In addition, the bladder contractions induced by electrical-field stimulation (EFS) and carbachol were significantly reduced, whereas angiotensin II-induced urethral contractions were significantly increased in OVX rats. Testosterone replacement at 10mg/kg (but not at 5mg/kg) dose fully normalized the in vivo micturition dysfunction, as well as the in vitro bladder and urethral alterations. Testosterone (10mg/kg) also significantly potentiated the bladder relaxations induced by the β₃-adrenoceptor agonist mirabegron. The protective effects of testosterone were not modified by concomitant treatment with the aromatase inhibitor letrozole (2.5mg/kg, 4weeks).

SIGNIFICANCE

The improvement of micturition dysfunction by testosterone replacement suggests that androgen therapy might be of therapeutic benefit for urological complications associated with post-menopause.

Acute myocardial infarction in a young bodybuilder taking anabolic androgenic steroids: A case report and critical review of the literature

We describe a case report of a 30-year-old bodybuilder suffering acute myocardial infarction (AMI). He had been taking stanozolol and testosterone for two months. The coronary angiogram showed high thrombotic burden in the left anterior descending artery without underlying atherosclerosis. Few case reports of AMI in athletes taking anabolic androgenic steroids (AASs) have been reported so far. AAS-related AMI is possibly underreported in the medical literature due to the desire of the affected individuals to hide AAS use. Physicians should always consider the possibility of AAS abuse in the context of a young athlete suffering AMI. AASs can predispose to AMI through the acceleration of coronary atherosclerosis. Additionally, thrombosis without underlying atherosclerosis or vasospasm is highly possible to cause AMI in AAS users. Complications after AMI may be more frequent in AAS users.

Dose-effects of aorta-infused clenbuterol on spinal cord ischemia-reperfusion injury in rabbits

Background

The β₂ adrenergic receptor (β₂AR) plays an important role in ischemia-reperfusion (I/R) injury in various organs. Recently, a selective β₂AR agonist clenbuterol was suggested to protect against cerebral I/R injury. This study was designed to investigate changes of β₂ARs after spinal cord I/R injury and dose-effects of aorta-infused clenbuterol on spinal cord I/R injury in rabbits.

Methods

Spinal cord ischemia was induced in New Zealand white rabbits by infrarenal abdominal aortic occlusion with a balloon catheter for 30 minutes except the sham group. During occlusion, nothing (I/R group), normal saline (NS group) or clenbuterol at different doses of 0.005, 0.01, 0.05, 0.1, 0.5, or 1 mg/kg (C_0.005, C_0.01, C_0.05, C_0.1, C_0.5, and C₁ groups) was infused into the occluded aortic segments. The hemodynamic data, blood glucose and serum electrolytes were measured during experimental period. Neurological function was assessed according to the modified Tarlov scales until 48 hours after reperfusion. After that, the lumbar spinal cord was harvested for β₂AR immunohistochemistry and histopathologic evaluation in the anterior horns.

Results

The β₂AR expression in the anterior horns of the spinal cord was significantly higher in the I/R group than in the sham group. Tarlov scores and the number of viable α-motor neurons were higher in C_0.01-C_0.5 groups than in the NS group, C_0.005 and C₁ groups and were highest in the C_0.1 group. Hypotension and hyperglycemia were found in the C₁ group.

Conclusion

β₂ARs in the anterior horn were upregulated after spinal cord I/R injury. Aortic-infused clenbuterol (0.01–0.5 mg/kg) can attenuate spinal cord I/R injury dose-dependently during the ischemic period. The Optimal dosage was 0.1 mg/kg. Activation of β₂AR could be a new therapeutic strategy for the treatment of spinal cord I/R injury.

Nesfatin-1 as a novel cardiac peptide: identification, functional characterization, and protection against ischemia/reperfusion injury

Nesfatin-1 is an anorexic nucleobindin-2 (NUCB2)-derived hypothalamic peptide. It controls feeding behavior, water intake, and glucose homeostasis. If intracerebrally administered, it induces hypertension, thus suggesting a role in central cardiovascular control. However, it is not known whether it is able to directly control heart performance. We aimed to verify the hypothesis that, as in the case of other hypothalamic satiety peptides, Nesfatin-1 acts as a peripheral cardiac modulator. By western blotting and QT-PCR, we identified the presence of both Nesfatin-1 protein and NUCB2 mRNA in rat cardiac extracts. On isolated and Langendorff-perfused rat heart preparations, we found that exogenous Nesfatin-1 depresses contractility and relaxation without affecting coronary motility. These effects did not involve Nitric oxide, but recruited the particulate guanylate cyclase (pGC) known as natriuretic peptide receptor A (NPR-A), protein kinase G (PKG) and extracellular signal-regulated kinases1/2 (ERK1/2). Co-immunoprecipitation and bioinformatic analyses supported an interaction between Nesfatin-1 and NPR-A. Lastly, we preliminarily observed, through post-conditioning experiments, that Nesfatin-1 protects against ischemia/reperfusion (I/R) injury by reducing infarct size, lactate dehydrogenase release, and postischemic contracture. This protection involves multiple prosurvival kinases such as PKCε, ERK1/2, signal transducer and activator of transcription 3, and mitochondrial K(ATP) channels. It also ameliorates contractility recovery. Our data indicate that: (1) the heart expresses Nesfatin-1, (2) Nesfatin-1 directly affects myocardial performance, possibly involving pGC-linked NPR-A, the pGC/PKG pathway, and ERK1/2, (3) the peptide protects the heart against I/R injury. Results pave the way to include Nesfatin-1 in the neuroendocrine modulators of the cardiac function, also encouraging the clarification of its clinical potential in the presence of nutrition-dependent physio-pathologic cardiovascular diseases.

Testosterone modulation of cardiac β-adrenergic signals in a rat model of heart failure

In this study, we examined the effects of castration and testosterone replacement on β-adrenoceptor and G protein expression in rats subjected to doxorubicin-induced heart failure. Five groups were included in this report: control, sham-castration with heart failure, castration with heart failure, castration+testosterone replacement with heart failure and castration+testosterone replacement and flutamide with heart failure. At 4 weeks post-treatment, echocardiography, hemodynamics and histopathology were assessed. Castration led to a further deterioration in myocardial performance, apoptosis and fibrosis, while testosterone replacement ameliorated these effects. Data obtained from Western blots revealed that testosterone upregulated the expression of β(2)-adrenoceptor, Gs, Gi(2) and bcl2 levels, downregulated the expression of β(3)-adrenoceptor, Gi(3) and GRK2 levels, and did not modify the expression of β(1)-adrenoceptor levels in the hearts of castrated rats subjected to doxorubicin-induced heart failure. Analyses of serum 17β-estradiol concentrations test confirmed that these effects of testosterone were exerted through the androgen pathway. Thus our findings suggest that testosterone may have beneficial effects for male heart failure patients with androgen deficiency and this protection involves modulation of the cardiac β-adrenergic system.