Testosterone replacement therapy in male hypogonadism

The association of testosterone with sarcopenia and frailty in chronic liver disease

BACKGROUND

Testosterone is an important anabolic hormone responsible for maintaining body composition and muscle mass and circulates mostly albumin-bound, or sex hormone binding globulin (SHBG)-bound or free in the plasma. Of these fractions, the latter is bioactive and exerts the androgenic effects on male population. Liver cirrhosis, the advanced stage of any chronic liver disease characterized by permanent distortions to the hepatic architecture, disrupts the hypothalamic-pituitary-gonadal axis, leading to diminished levels of free testosterone and hypogonadism.

METHODS

We retrieved the PubMed database to provide a synopsis of testosterone's physiology and action and summarize the effect of sarcopenia in pre-cirrhotic and cirrhotic patients. Moreover, we scoped to provide insight into the relationship of testosterone levels with sarcopenia, frailty and survival in cirrhotic and non-cirrhotic population as well as to discuss the efficacy of exogenous testosterone supplementation on the anthropometric parameters and survival of those patients.

RESULTS

Low testosterone levels have been associated with sarcopenia, reduced body lean mass, decreased bone mineral density and frailty, thus leading to increased morbidity and mortality especially among cirrhotic patients. Furthermore, exogenous testosterone administration significantly ameliorated body composition on patients with chronic hepatic disease, without significant adverse effects. However, the current literature does not suggest any significant effect on survival of those patients. Moreover, the long-term safety of testosterone use remains an open question.

CONCLUSION

Low serum testosterone is strongly correlated with sarcopenia, frailty, higher rate of hepatic decompensation and mortality. Nonetheless, exogenous supplementation of testosterone did not ameliorate the liver-related outcomes and complications.

Endocrine treatment of transgender individuals: current guidelines and strategies

INTRODUCTION

This review summarizes gender affirming medical and surgical care available to transgender individuals, along with proposals to improve medically and culturally appropriate care.

AREAS COVERED

Transgender individuals are those whose gender identity differs from that recorded at birth (usually based on visualization of external sexual anatomy). In order to align the body with the patient's gender identity, clinicians can provide hormone therapy (HT) to bring sex hormone levels to the range associated with the patient's gender identity. At steady state, monitoring for maintenance of levels, as well as for known risks and complications, is required. Treating clinicians should have knowledge of trans assessment criteria, hormone therapy, surgical options, primary care, and mental health needs of transgender patients. A narrative literature review was conducted using Pubmed and EMBASE with articles then selected for relevance. The initial search terms were: androgen suppression, antiandrogen, breast development, chest reconstruction, cisgender, estrogen, fertility preservation, gender-affirming surgery, gender identity, gender incongruence, genital reconstruction, hormone replacement, hyperlipidemia, orchiectomy, prolactin, prostate atrophy, spermatogenesis, spironolactone, testosterone, thrombogenesis, transgender, and virilization.

EXPERT OPINION

Although guidelines exist and examples of training are available, systematic formal training must be implemented to truly mainstream high-quality gender-affirming health care .

Combined low-dose testosterone and vildagliptin confers cardioprotection in castrated obese rats

Although a physiological dose of testosterone replacement therapy (p-TRT) has been shown to improve left ventricular (LV) function, some studies reported that it increased the risk of myocardial infarction in testosterone-deprived men. We previously reported that vildagliptin might be used as an alternative to the p-TRT. In this study, we hypothesized that a combined low-dose TRT with vildagliptin exerts greater efficacy than single regimen in improving cardiometabolic function in obese-insulin resistant rats with testosterone deprivation. Male rats were fed on a normal diet or high-fat diet for 12 weeks. Then, they were divided into 2 subgroups; sham operation and orchiectomy (NDO, HFO) and fed their diets for another 12 weeks. At week 25, orchiectomized rats were subdivided into 4 groups, vehicle, p-TRT, vildagliptin, and combined drugs. At week 29, cardiometabolic and biochemical parameters were determined. HFO rats had obese-insulin resistance with a worse LV dysfunction, compared with sham. Vildagliptin and combined drugs effectively reduced insulin resistance. All treatments reduced blood pressure, cardiac autonomic imbalance, LV dysfunction, mitochondrial dysfunction, apoptosis, and increased mitochondrial fusion in NDO and HFO rats. However, p-TRT and combined drugs, but not vildagliptin, reduced mitochondrial fission in NDO and HFO rats. We concluded that combined low-dose TRT with vildagliptin mitigated LV function at a similar level to the p-TRT alone and vildagliptin via improving mitochondrial fusion, reducing mitochondrial dysfunction and apoptosis in testosterone-deprived rats. Our findings suggest that low-dose TRT combined with vildagliptin may be an alternative for p-TRT in conditions of obese-insulin resistance with testosterone deprivation.

Pharmacology of testosterone replacement therapy preparations

The goal of testosterone replacement therapy (TRT) is to return serum testosterone levels to within physiologic range and improve symptoms in hypogonadal men. Some of the symptoms aimed to improve upon include decreased libido, erectile dysfunction, infertility, hot flashes, depressed mood, and loss of muscle mass or hair. Clinical use of testosterone for replacement therapy began approximately 70 years ago. Over the decades, numerous preparations and formulations have been developed primarily focusing on different routes of delivery and thus pharmacokinetics (PKs). Currently the routes of delivery approved for use by the United States Food and Drug Administration encompasses buccal, nasal, subdermal, transdermal, and intramuscular (IM). Many factors must be considered when a clinician is choosing the most correct formulation for a patient. As this decision depends highly on the patient, active patient participation is important for effective selection. The aim of this review is to describe and compare all testosterone preparations currently available and approved by the United States Food and Drug Administration. Areas of focus will include pharmacology, PKs, adverse effects, and specifics related to individual delivery routes.

The potent synthetic androgens, dimethandrolone (7α,11β-dimethyl-19-nortestosterone) and 11β-methyl-19-nortestosterone, do not require 5α-reduction to exert their maximal androgenic effects

Dimethandrolone (DMA: 7α,11β-dimethyl-19-nortestosterone) and 11β-methyl-19-nortestosterone (MNT) are potent androgens in development for hormonal therapy in men. As 5α-reduced androgens, such as 5α-dihydrotestosterone (DHT), may raise the risk of benign prostate hyperplasia, accelerate the development of prostate carcinoma, and increase male pattern baldness and acne, we investigated the role of 5α-reduction in the androgenic activity of DMA and MNT. The authentic 5α-reduced metabolites, 5α-dihydroDMA (5α-DHDMA) and 5α-dihydroMNT (5α-DHMNT), were prepared by chemical synthesis and compared in vitro and in vivo to the parent compounds. Both 5α-reduced androgens bound with high affinity to the rat androgen receptor (AR) and were potent inducers of transactivation of 3XHRE-LUC in CV-1 cells cotransfected with a human AR expression plasmid. To examine in vivo androgenic (stimulation of ventral prostate [VP] and seminal vesicle [SV] weights) and anabolic (stimulation of levator ani [LA] muscle weights) activity, 22-day-old castrate male rats were treated sc for 7 days with various doses of DMA, 5α-DHDMA, or testosterone (T) or MNT, 5α-DHMNT, or T and necropsied on day 8. 5α-DHDMA was at least threefold more potent than T in stimulating growth of the VP but only 30-40% as potent as DMA. 5α-DHMNT was four- to eightfold more potent than T, whereas MNT was approximately equipotent to T. To assess the possible role of 5α-reduction in VP and SV growth, castrate immature rats were treated with maximally effective doses of T, DHT, DMA, MNT, or the related 19-norandrogen, 7α-methyl-19-nortestosterone (MENT), or vehicle, with or without dutasteride (DUT), an inhibitor of 5α-reductases types 1 and 2. In rats treated with T+DUT, serum T was significantly higher (P<0.05) than in rats treated with T alone, and serum DHT was decreased (P<0.001) to levels observed in castrate vehicle-treated rats. DUT significantly reduced both VP and SV weights in T-treated rats, whereas there was no significant effect of DUT on weights of these accessory sex glands in rats treated with DMA, MNT, DHT, or MENT. These results indicate that inhibition of 5α-reductase activity in vivo does not affect the androgenic potency of DMA, MNT, or MENT.

Dimethandrolone (7alpha,11beta-dimethyl-19-nortestosterone) and 11beta-methyl-19-nortestosterone are not converted to aromatic A-ring products in the presence of recombinant human aromatase

Dimethandrolone undecanoate (DMAU: 7alpha,11beta-dimethyl-19-nortestosterone 17beta-undecanoate) is a potent orally active androgen in development for hormonal therapy in men. Cleavage of the 17beta-ester bond by esterases in vivo leads to liberation of the biologically active androgen, dimethandrolone (DMA), a 19-norandrogen. For hormone replacement in men, administration of C19 androgens such as testosterone (T) may lead to elevations in circulating levels of estrogens due to aromatization. As several reports have suggested that certain 19-norandrogens may serve as substrates for the aromatase enzyme and are converted to the corresponding aromatic A-ring products, it was important to investigate whether DMA, the related compound, 11beta-methyl-19-nortestosterone (11beta-MNT), also being tested for hormonal therapy in men, and other 19-norandrogens can be converted to aromatic A-ring products by human aromatase. The hypothetical aromatic A-ring product corresponding to each substrate was obtained by chemical synthesis. These estrogens bound with high affinity to purified recombinant human estrogen receptors (ER) alpha and beta in competitive binding assays (IC50's: 5-12 x 10(-9) M) and stimulated transcription of 3XERE-luciferase in T47Dco human breast cancer cells with a potency equal to or greater than that of estradiol (E2) (EC50's: 10(-12) to 10(-11) M). C19 androgens (T, 17alpha-methyltestosterone (17alpha-MT), androstenedione (AD), and 16alpha-hydroxyandrostenedione (16alpha-OHAD)), 19-norandrogens (DMA, 11beta-MNT, 19-nortestosterone (19-NT), and 7alpha-methyl-19-nortestosterone (MENT)) or the structurally similar 19-norprogestin, norethindrone (NET) were incubated at 50 microM with recombinant human aromatase for 10-180 min at 37 degrees C. The reactions were terminated by extraction with acetonitrile and centrifugation, and substrate and potential product were separated by HPLC. Retention times were monitored by UV absorption, and UV peaks were quantified using standard curves. Aromatization of the positive controls, T, AD, and 16alpha-OHAD was linear for 40-60 min, and conversion of T or AD was complete by 120 min. The nonsteroidal aromatase inhibitor, letrozole, demonstrated concentration-dependent suppression of T aromatization. Under the same conditions, there was no detectable conversion of DMA, 11beta-MNT, or NET to their respective hypothetical aromatic A-ring products during incubation times up to 180 min. Aromatization of MENT and 19-NT proceeded slowly and was limited. Collectively, these data support the notion that in the absence of the C19-methyl group, which is the site of attack by oxygen, aromatization of androgenic substrates proceeds slowly or not at all and that this reaction is impeded by the presence of a methyl group at the 11beta position.

Hypertrophy with unilateral resistance exercise occurs without increases in endogenous anabolic hormone concentration

We aimed to gain insight into the role that the transitory increases in anabolic hormones play in muscle hypertrophy with unilateral resistance training. Ten healthy young male subjects (21.8 +/- 0.4 years, 1.78 +/- 0.04 m, 75.6 +/- 2.9 kg; mean +/- SE) engaged in unilateral resistance training for 8 week (3 days/week). Exercises were knee extension and leg press performed at 80-90% of the subject's single repetition maximum (1RM). Blood samples were collected in the acute period before and after the first training bout and following the last training bout and analyzed for total testosterone, free-testosterone, luteinizing hormone, sex hormone binding globulin, growth hormone, cortisol, and insulin-like growth factor-1. Thigh muscle cross sectional area (CSA) and muscle fibre CSA by biopsy (vastus lateralis) were measured pre- and post-training. Acutely, no changes in systemic hormone concentrations were observed in the 90 min period following exercise and there was no influence of training on these results. Training-induced increases were observed in type IIx and IIa muscle fibre CSA of 22 +/- 3 and 13 +/- 2% (both P < 0.001). No changes were observed in fibre CSA in the untrained leg (all P > 0.5). Whole muscle CSA increased by 5.4 +/- 0.9% in the trained leg (P < 0.001) and remained unchanged in the untrained leg (P = 0.76). Isotonic 1RM increased in the trained leg for leg press and for knee extension (P < 0.001). No changes were seen in the untrained leg. In conclusion, unilateral training induced local muscle hypertrophy only in the exercised limb, which occurred in the absence of changes in systemic hormones that ostensibly play a role in muscle hypertrophy.

Dimethandrolone undecanoate: a new potent orally active androgen with progestational activity

Dimethandrolone (DMA), the 17beta-undecanoic acid ester of dimethandrolone (DMAU; 7alpha,11beta-dimethyl-19-nortestosterone) is a potent androgen currently in development for therapeutic uses in men. Cleavage of the 17beta-ester bond liberates the biologically active DMA. In this study we investigated the activity of DMAU and DMA both in vivo and in vitro. DMAU was active orally in castrate rat bioassays, and when administered sc, a single dose produced prolonged androgenic activity and suppression of LH with sustained circulating levels of DMA. DMA, other 19-norandrogens, and C-19 androgens bound to recombinant rat androgen receptor with high affinity and were equipotent in stimulating luciferase activity (EC50, 10(-10) -10(-9) M) in CV-1 cells cotransfected with a human androgen receptor expression vector and a luciferase reporter plasmid with three hormone response elements. Because various 19-norandrogens are also known to bind to progestin receptors (PR) and to possess progestational activity in vivo, we evaluated the binding affinity of DMA for rabbit PR and recombinant human PR-A and PR-B and its ability to induce PR-mediated transcription and endogenous alkaline phosphatase activity in T47DCO human breast cancer cells. DMA and related 19-norandrogens bound with high affinity to both rabbit and human PR, whereas the less active 11alpha-methyl stereoisomer of DMA and C-19 androgens showed low or negligible binding to PR. In T47DCO cells, 10(-8) M DMA and other 19-norandrogens stimulated transcription of a progestin/glucocorticoid/androgen response element-thymidine kinase-luciferase reporter plasmid to the same extent as R5020, the potent progestin promegestone (EC50, approximately 10(-9) M), but C-19 androgens had no effect. Antiprogestins were potent inhibitors of transactivation and alkaline phosphatase activity induced by DMA and other 19-norandrogens in T47DCO cells, whereas antiandrogens were weak inhibitors. DMA and DMAU also exhibited dose-dependent progestational activity in the estrogen-primed immature female rabbit, as assessed by induction of endometrial gland arborization. The dual androgenic and progestational activities of DMA make it a potential candidate for a single-agent male contraceptive as well as for androgen therapy in men, pending a successful outcome of pharmacokinetic and toxicity studies currently in progress.

The endocrine pharmacology of testosterone therapy in men

The review starts off by outlining the history of the discovery of the male sex hormone testosterone and the historical background to the various, often dubious, approaches to the treatment of age-related endocrine disorders in older men. A discussion of congenital androgen deficiency in young men is followed by methods of diagnosing hypogonadism in older men. Among therapeutic options, the alternatives to direct testosterone replacement are discussed, although none of them have proved to be particularly successful in clinical practice. For testosterone replacement itself, various routes of administration and pharmaceutical formulations are now available, facilitating good monitoring and individualized therapy.

Testosterone metabolism, dose-response relationships and receptor polymorphisms: selected pharmacological/toxicological considerations on benefits versus risks of testosterone therapy in men

In this review selected toxicological problems related to testosterone therapy in hypogonadal men are discussed. Applying "classical" pharmacological/toxicological findings (e.g. animal studies on short- and long-term toxicity) to clinical situations is not very helpful. Molecular biological knowledge and especially evaluation of epidemiological studies, as well as intervention studies, on testosterone therapy in hypogonadal men are more useful. Potential risks include overdosage for lifestyle reasons, e.g. excessive muscle building and reduction of visceral obesity, when erythrocytosis occurs concomitantly. Modern galenic formulations of testosterone administration (e.g. transdermal gel, suitable testosterone esters for intramuscular application and newer oral preparations) avoid supraphysiological serum concentrations, therefore significantly reducing the toxicological risk. A hypothetical model of the toxicological risks of testosterone therapy is given that is based on the influence of testosterone metabolism (aromatization vs. reduction) of the respective parameter/target chosen. Finally, the great influence of polymorphisms of the androgen receptor on the assessment of toxicological risk and on the individualization of androgen therapy is shown. Already existing national, continental and international guidelines or recommendations for the testosterone therapy should be harmonized.