Testosterone and cardiovascular disease – the controversy and the facts

Enucleated bone marrow-derived mesenchymal stromal cells regulate immune microenvironment and promote testosterone production through efferocytosis

BACKGROUND

Testosterone deficiency (TD) occurs most frequently in older men and can cause many health problems. Testosterone replacement therapy (TRT) is widely used to treat TD, but this regimen can lead to a series of side effects. Stem cell therapy has been wildly studied in vitro. However, due to the multidirectional differentiation potential and heterogeneity of stem cells, it is difficult to achieve the good efficiency and reproducibility in basic research and clinical applications. This study aims to identify a new strategy for the treatment of TD.

METHODS

Bone marrow-derived mesenchymal stromal cells (BMSCs) were enucleated by Ficoll density gradient centrifugation. The organelles and cellular functions of enucleated BMSCs were analyzed by immunofluorescence staining and flow cytometry. Extracellular vesicles (EVs) were isolated by ultracentrifugation and characterized. For the animal studies, enucleated BMSCs were labelled with Mitotracker and injected into ethane dimethanesulfone (EDS)-treated rats. Testosterone production and spermatogenesis were detected at different time points through various tests. To determine the mechanism of efferocytosis, we analysed the number of macrophages by immunofluorescence staining and quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

The injection of enucleated BMSCs (Cargocytes) into the testes of EDS-treated rats restored the levels of serum testosterone, increased the number of Leydig cells (LCs), and improved spermatogenesis. We found that enucleated BMSCs underwent apoptosis earlier than BMSCs did. Subsequently, testicular interstitial macrophages phagocytosed apoptotic enucleated BMSCs through efferocytosis. Efferocytosis promoted macrophage polarization from the M1 to the M2 phenotype, reduced the expression of proinflammatory cytokines, and decreased the levels of inflammation and oxidative stress.

CONCLUSIONS

In summary, this study pioneered the application of stromal cell enucleation technology to repair tissue damage in the reproductive system, explored the potential of cell burial in the treatment of reproductive system diseases and provided a new approach for the clinical treatment of male infertility.

Androgen Society Position Paper on Cardiovascular Risk With Testosterone Therapy

The Androgen Society is an international, multidisciplinary medical organization committed to advancing research and education in the field of testosterone deficiency and testosterone therapy (TTh). This position paper is written in response to results of the TRAVERSE study, published in June 2023, which reported no increased risk of major adverse cardiovascular events (MACE) in men who received TTh compared with placebo. In 2013-2014, 2 observational studies reported increased cardiovascular (CV) risks with TTh and received wide media attention. Despite strong criticism of those 2 studies, in 2015, the Food and Drug Administration added a CV warning to testosterone product labels and required pharmaceutical companies to perform a CV safety study, which became the TRAVERSE trial. TRAVERSE enrolled 5246 men at high risk for MACE based on existing heart disease or multiple risk factors. Participants were randomized to daily testosterone gel or placebo gel, with a mean follow-up of 33 months. Results revealed no greater risk of MACE (myocardial infarction, stroke, or CV death) or venothrombotic events in men who received TTh compared with placebo. Review of the prior literature reveals near uniformity of studies reporting no increased MACE with TTh. This includes 2 additional large randomized controlled trials, multiple smaller randomized controlled trials, several large observational studies, and 19 meta-analyses. In view of these findings, it is the position of the Androgen Society that it has now been conclusively determined that TTh is not associated with increased risks of heart attack, stroke, or CV death.

Major adverse cardiovascular events associated with testosterone treatment: a pharmacovigilance study of the FAERS database

Background and purpose: Testosterone is an essential sex hormone in maintaining masculine characteristics, which is prescribed for male hypogonadism as testosterone replacement treatment (TRT). Herein, we investigated long-standing controversies about the association between TRT and major adverse cardiovascular events (MACEs), based on real world adverse event (AE) reports, registered in the Food and Drug Administration Adverse Event Reporting System (FAERS). Methods: Publicly available FAERS data from 1 January 2004 to 31 December 2022 were retrieved from the Food and Drug Administration (FDA) website. The data mining protocol including the reporting odds ratio (ROR) and the Bayesian confidence propagation neural network (BCPNN) was applied to analyze overreporting caused by risk factors and MACEs, including TRT, morbidities, and ages. The ROR and the BCPNN were also applied to investigate the annually developing trend of pharmacovigilance (PV) signals in the real world, retrospectively. Results: A total of 3,057 cases referring to MACEs, with a median age of 57 years old (yo), were identified from 28,921 cases of testosterone users. MACEs related to PV signals have emerged since 2014, including cardiac death, non-fatal myocardial infarction, and non-fatal stroke. Myocardial infarction (MI) (ROR: 9.46; IC₀₂₅: 3.08), acute myocardial infarction (AMI) (ROR: 16.20; IC₀₂₅: 3.72), ischemic cardiomyopathy (ROR: 11.63; IC₀₂₅: 2.20), and cardiomyopathy (ROR: 5.98; IC₀₂₅: 1.96) were the most significant signals generated, and weaker signals included cardiac failure acute (ROR: 4.01; IC₀₂₅: 0.71), cardiac arrest (ROR: 1.88; IC₀₂₅: 0.56), and ventricular fibrillation (VF) (ROR: 2.38; IC₀₂₅: 0.38). The time-to-onset (TTO) of MACEs was calculated with a median of 246 days for AMI. Conclusion: For myocardial infarction and cardiomyopathy, TRT statistically tended to increase the risk of MACEs, while for cardiac arrhythmia, cardiac failure, and stroke, TRT demonstrated beneficial effects among the population with morbidities, such as testosterone deficiency (TD), diabetes mellitus (DM), and hypertension. MACEs were rare but led to serious outcomes including significant increase in death and disability. Since 2018, and before 2014, reports referring to TRT associated with MACEs were relatively scarce, which indicated that there might be a considerable number of cases that went unrecorded, due to neglection. Health workers and testosterone users might pay more attention to testosterone-induced MACEs.

Testosterone deficiency prevents left ventricular contractility dysfunction after myocardial infarction

Testosterone may affect myocardial contractility since its deficiency decreases the contraction and relaxation of the heart. Meanwhile, testosterone replacement therapy has raised concerns because it may worsen cardiac dysfunction and remodeling after myocardial infarction (MI). In this study, we evaluate cardiac contractility 60 days after MI in rats with suppressed testosterone. Male Wistar rats underwent bilateral orchidectomy one week before the ligation of the anterior descending left coronary artery. The animals were divided into orchidectomized (OCT); MI; orchidectomized + MI (OCT + MI); orchidectomized + MI + testosterone (OCT + MI + T) and control (Sham) groups. Eight weeks after MI, papillary muscle contractility was analyzed under increasing calcium (0.62, 1.25, 2.5 and 3.75 mM) and isoproterenol (10^-8 to 10^-2 M) concentrations. Ventricular myocytes were isolated for intracellular calcium measurements and assessment of Ca²⁺ handling proteins. Contractility was preserved in the orchidectomized animals after myocardial infarction and was reduced when testosterone was replaced (Ca²⁺ 3.75 mM: Sham: 608 ± 70 (n = 11); OCT: 590 ± 37 (n = 16); MI: 311 ± 33* (n = 9); OCT + MI: 594 ± 76 (n = 7); OCT + MI + T: 433 ± 38* (n=4), g/g *p < 0.05 vs Sham). Orchidectomy also increased the Ca²⁺ transient amplitude of the ventricular myocytes and SERCA-2a protein expression levels. PLB phosphorylation levels at Thr¹⁷ were not different in the orchidectomized animals compared to the Sham animals but were reduced after testosterone replacement. CAMKII phosphorylation and protein nitrosylation increased in the orchidectomized animals. Our results support the view that testosterone deficiency prevents MI contractility dysfunction by altering the key proteins involved in Ca²⁺ handling.

Testosterone treatment and cardiovascular and venous thromboembolism risk: what is 'new'?

In men, testosterone (T) production declines as a function of ageing. Late-onset hypogonadism (LOH) is the most commonly used term to indicate this age-related condition. In LOH, the relative clinical significance and the potential benefit of testosterone treatment (TTh) are still the subject of strong criticisms in the scientific community. The debate is further complicated by the recent position statement of the US Food and Drug Administration (FDA) emphasizing that, in LOH, the benefits and safety of TTh have not been fully established. Hence, the FDA required a labeling change to inform patients about a possible increased cardiovascular (CV) risk of TTh. Similar considerations were previously released by the FDA and by Health Canada concerning a TTh-related venous thromboembolism (VTE) risk. In this review, we will summarize the available evidence concerning a possible link among TTh and CV and VTE risks. For this purpose, data derived from epidemiological studies analyzing relationships between the aforementioned risks and endogenous T levels will be analyzed. In addition, evidence deriving from interventional studies including pharmacoepidemiological and placebo-controlled randomized controlled trials (RCTs) will be examined. Our analysis shows that available data do not support an increased CV risk related to TTh. Similar considerations can be drawn for the relationship between TTh and VTE. The previously reported cases of TTh-related VTE were frequently related to a previously undiagnosed thrombophilia-hypofibrinolysis status. Hence, an anamnestic screening for thrombophilia before starting TTh is recommended, just as it is for the use of oral contraceptives.

Testosterone therapy in men with testosterone deficiency: are the benefits and cardiovascular risks real or imagined?

In the adult male, testosterone (T) deficiency (TD) also known as male hypogonadism, is a well-established medical condition, which has been recognized for more than a century. T therapy in men with TD was introduced as early as 1940s and was reported to improve overall health with no concomitant serious adverse effects. A wealth of recent studies demonstrated that T therapy in men with TD is associated with increased lean body mass, reduced fat mass and waist circumference, improvement in glycemic control, and reduced obesity. T therapy is also associated with improvements in lipid profiles, amelioration of metabolic syndrome (Met S) components, reduced inflammatory biomarkers, reduced systolic and diastolic blood pressure, and improvements in sexual function. More importantly, T therapy is associated with amelioration of diabetes and reduced mortality. However, few studies, marred with serious methodological and analytical flaws reported between 2010 and 2014, suggested that T therapy is associated with increased cardiovascular (CV) risk. As summarized in this review, a thorough and critical analysis of these studies showed that the risks purported are unsubstantiated and such studies lacked credible scientific and clinical evidence. Moreover, recent observational, registry studies, clinical trials, and meta-analyses, all revealed no increase in CV risks in men receiving T therapy. In this review, the benefits of T therapy in adult men with TD and the lack of credible evidence suggesting that T therapy is linked to increased CV risks are discussed. It should be noted that the literature is replete with studies demonstrating beneficial effects of T therapy on CV and overall health.

Testosterone Replacement Therapy: The Emperor's New Clothes

The mean age of the world population has steadily increased in the last decades, as a result of increased life expectancy and reduced birth rate. Global aging has led to a greater worldwide cost for healthcare: hormonal alterations contribute to the pathogenesis of several conditions and might cause a significant reduction in the perceived sense of well-being. Menopause is archetypal of hormonal alterations occurring during aging: in males, sex hormones do not decrease abruptly, yet testosterone levels decrease steadily and continuously during aging, ultimately resulting in late-onset hypogonadism. Treatment of this condition might mitigate most symptoms; however, testosterone replacement therapy (TRT) should be prescribed only in selected patients and it should not be considered as an antiaging treatment. In recent years, different authors have questioned health risks associated with testosterone treatment; while position statements from many scientific societies seem to be reassuring, the Food and Drug Administration has issued a warning in regard to the possible side effects of this therapy. We aim to review recent controversies and discoveries in regard to TRT.

Testosterone deficiency in the aging male

Treatment for hypogonadism is on the rise, particularly in the aging population. Yet treatment in this population represents a unique challenge to clinicians. The physiology of normal aging is complex and often shares the same, often vague, symptoms of hypogonadism. In older men, a highly prevalent burden of comorbid medical conditions and polypharmacy complicates the differentiation of signs and symptoms of hypogonadism from those of normal aging, yet this differentiation is essential to the diagnosis of hypogonadism. Even in older patients with unequivocally symptomatic hypogonadism, the clinician must navigate the potential benefits and risks of treatment that are not clearly defined in older men. More recently, a greater awareness of the potential risks associated with treatment in older men, particularly in regard to cardiovascular risk and mortality, have been appreciated with recent changes in the US Food and Drug Administration recommendations for use of testosterone in aging men. The aim of this review is to provide a framework for the clinician evaluating testosterone deficiency in older men in order to identify correctly and treat clinically significant hypogonadism in this unique population while minimizing treatment-associated harm.

Diagnosing hypogonadism and treating decisions in different parts of the world: shifts in patterns between 2006 and 2015

AIM

Variations in diagnosing and treating testosterone (T) deficiency between different regions of the world were analyzed in 2006, and repeated in 2010. At present, the changes since 2006 were analyzed.

METHODS

About 731 physicians were interviewed in Europe, South Africa, Central and South America regarding factors determining: (1) prescription of T or withholding T, (2) factors in the long-term use of T and the role of T formulations therein, (3) awareness of the wider spectrum of action of T (cardiometabolic disease) (4) reimbursement of T and its impact on (continued) use and (5) best strategies for information on T for physicians.

RESULTS

Total T was a key factor in identifying hypogonadism, but for >80% of physicians, clinical symptoms were weighed during diagnosis. Once diagnosed, >85% received T treatment, but the treatment compliance was problematic. Of these patients, 36% decided not to start or continue the treatment.

CONCLUSION

More hypogonadal men are treated than before, but ∼20% goes unidentified. Physicians have a greater awareness that T deficiency can be an element in cardiovascular and metabolic disease, but more education of physicians on diagnosis and treatment of hypogonadism are needed. Problems with reimbursement of T are barriers in the prescription of T and its use by patients.

Effects of intermission and resumption of long-term testosterone replacement therapy on body weight and metabolic parameters in hypogonadal in middle-aged and elderly men

OBJECTIVE

In addition to primary and secondary ('classical') hypogonadism, hypogonadism occurring in middle-aged and elderly men has been recognized. There is evidence that restoring T levels to normal improves body weight, serum lipids and glucose levels.

DESIGN

Observational registry study.

PATIENTS

Two hundred and sixty-two hypogonadal, middle-aged and elderly, men received testosterone replacement treatment (TRT). After having been on TRT for a mean duration of 65·5 months, TRT was temporarily intermitted in 147 patients for a mean of 16·9 months (Group I) due to cost reimbursement issues and in seven men due to prostate cancer. All these men resumed TRT for a mean period of 14·5 months. Of the cohort, 115 men were treated continuously (designated as Group C). To compare on-treatment to off-treatment periods, three periods of equal duration were defined: pre-intermission (on TRT), during intermission (off TRT) and post-intermission (on TRT after resumption of TRT). For proper comparison, the same periods were analysed for those patients who continued TRT throughout (Group C).

MEASUREMENTS

Variables of body weight, glucose metabolism, lipids, blood pressure and C-reactive protein (CRP).

RESULTS

In Group C there was a continuous improvement of body weight, serum lipids, glucose, HbA1c , blood pressure and CRP. In Group I there was a similar initial improvement which was reversed upon intermission of T administration but which appeared again when T treatment was reinstated.

CONCLUSIONS

Our observation indicates that T administration improves body weight and metabolic factors in men with hypogonadism but withdrawal of T reverses these beneficial effects to appear again when TRT is resumed.