Advantages and Limitations of Androgen Receptor-Based Methods for Detecting Anabolic Androgenic Steroid Abuse as Performance Enhancing Drugs

The Uses of Anabolic Androgenic Steroids Among Athletes; Its Positive and Negative Aspects- A Literature Review

The use of anabolic androgenic steroids (AAS) for strength training and muscle building is a widespread practice among athletes and young individuals. Athletes and bodybuilders are using these substances for various purposes, such as enhancing muscle mass, strengthening their bodies, and enhancing their performances. AAS exert a wide range of physiological effects that result in the activation of central signaling, resulting in adverse effects. Moreover, excessive use of AAS which can be categorized as AAS abuse; is linked to biological and psychological pathologies, which can lead to mortality. Complications arising from steroid abuse involve both cellular and physiological complications. Cellular complications arise when activation of signaling proteins like mTOR, Akt, etc. leads to alteration in protein synthesis pathways, cell cycle, oxidative stress, and apoptosis, contributing to damage at the cellular level. Physiological complications are evident with cardiovascular pathologies, including an altered lipid profile, cardiac hypertrophy, hypogonadism after discontinuation of AAS, and modulation of GABA receptors in the brain, all contributed by the androgen receptor signaling. Clinical complications budding from these altered physiological processes lead to clinical effects like testicular dysfunction, acne, gynecomastia, and neuropsychiatric disorders. Despite potential therapeutic benefits, AAS use is prohibited by the World Anti-Doping Agency (WADA) due to concerns over adverse health effects. This review highlights the molecular mechanisms, physiological processes, and clinical complications arising from the excessive use of AAS among athletes.

Detection of selective androgen receptor modulators (SARMs) in serum using a molecularly imprinted nanoparticle surface plasmon resonance sensor

Selective Androgen Receptor Modulators (SARMs) are a fairly new class of therapeutic compounds that act upon the androgen receptor. They proffer similar anabolic properties to steroids, but with a much-reduced androgenic profile. They have become a popular substance of abuse in competitive sport. Being relatively new, detection systems are limited to chromatographic methods. Here we present a surface plasmon resonance sensor for three commonly-used SARMS, Andarine, Ligandrol and RAD-140, using high-affinity molecularly imprinted nanoparticles (nanoMIPs) as the recognition element. Synthesised nanoMIPS exhibited dissociation constant (K_D) values of 29.3 nM, 52.5 nM and 75.1 nM for Andarine, Ligandrol and RAD-140 nanoMIPs, respectively. Cross-reactivity of the particles was explored using the alternative SARMs, with the nanoMIPs demonstrating good specificity. Fetal Bovine Serum (FBS) was used to assess the ability of the SPR-based nanoMIP sensor to detect the target compounds in a comparable biological matrix, with observed K_D values of 12.3 nM, 31.9 nM and 28.1 nM for Andarine, Ligandrol and RAD-140 nanoMIPs, respectively. Theoretical limits of detection (LoD) were estimated from a calibration plot in FBS and show that the nanoMIP-based sensors have the potential to theoretically measure these SARMs in the low to sub nM range. Crucially these levels are below the minimum required performance limit (MRPL) set for these compounds by WADA. This study highlights the power of modern molecular imprinting to rapidly address required molecular recognition for new compounds of interest.

Advances in the Determination of Anabolic-Androgenic Steroids: From Standard Practices to Tailor-Designed Multidisciplinary Approaches

Anabolic-androgenic steroids (AASs), a group of compounds frequently misused by athletes and, unfortunately, also by the general population, have lately attracted global attention; thus, significant demands for more precise, facile, and rapid AAS detection have arisen. The standard methods ordinarily used for AAS determination include liquid and gas chromatography coupled with mass spectrometry. However, good knowledge of steroid metabolism, pretreatment of samples (such as derivatization), and well-trained operators of the instruments are required, making this procedure expensive, complicated, and not routinely applicable. In the drive to meet current AAS detection demands, the scientific focus has shifted to developing novel, tailor-made approaches leading to time- and cost-effective, routine, and field-portable methods for AAS determination in various matrices, such as biological fluids, food supplements, meat, water, or other environmental components. Therefore, herein, we present a comprehensive review article covering recent advances in AAS determination, with a strong emphasis on the increasingly important role of chemically designed artificial sensors, biosensors, and antibody- and fluorescence-based methods.

A cell-free bioassay for the detection of androgens

Androgens remain abused performance-enhancing drugs in sports. Technologies based on mass spectrometry can detect all forms of androgens but fail if the androgen represents a novel structure. A bioassay detects androgens based on function rather than structure. To date, there has been limited adoption of cell-based in vitro bioassays as a screening tool for nontargeted androgen detection because they require expert personnel and specialized equipment to perform. We now describe the development of a cell-free version of an androgen in vitro bioassay. Stage 1 involved in vitro transcription/translation reactions (IVTT) using a DNA template encoding an enhancer/androgen response element (ARE) regulatory region upstream of a minimal promoter that drives expression of a reporter protein. The assay detected testosterone across the concentration range of 106.7 to 0.0144 ng/ml (3.7 × 10^-7 to 5 × 10^-11 M), with an EC₅₀ of 6.63 ng/ml (23 nM). To reduce complexity, Stages 2-4 of development included just in vitro transcription (IVT) reactions, whereby the output was an RNA molecule. Stage 2 involved directly labelling the RNA molecule with fluorophore-labelled nucleotide triphosphates, Stage 3 involved reverse transcription-polymerase chain reaction (PCR) of the RNA molecule, and Stage 4 utilized an RNA aptamer, Mango II, as its RNA output. The Stage 4 product detected testosterone across the range of 106.7-0.0001 ng/ml (3.7 × 10^-7 to 5 × 10^-13 M), with an EC₅₀ of 0.04 ng/ml (0.155 nM). Further to this, we show that the Stage 4 product can detect other androgenic molecules. Relative to cell-based bioassays, the Stage 4 product is easy to perform and could be developed into a routine, high-throughput, nontargeted androgen screen.

A Mechanistic High-Content Analysis Assay Using a Chimeric Androgen Receptor That Rapidly Characterizes Androgenic Chemicals

Human health is at risk from environmental exposures to a wide range of chemical toxicants and endocrine-disrupting chemicals (EDCs). As part of understanding this risk, the U.S. Environmental Protection Agency (EPA) has been pursuing new high-throughput in vitro assays and computational models to characterize EDCs. EPA models have incorporated our high-content analysis-based green fluorescent protein estrogen receptor (GFP-ER): PRL-HeLa assay, which allows direct visualization of ER binding to DNA regulatory elements. Here, we characterize a modified functional assay based on the stable expression of a chimeric androgen receptor (ARER), wherein a region containing the native AR DNA-binding domain (DBD) was replaced with the ERα DBD (amino acids 183-254). We demonstrate that the AR agonist dihydrotestosterone induces GFP-ARER nuclear translocation, PRL promoter binding, and transcriptional activity at physiologically relevant concentrations (<1 nM). In contrast, the AR antagonist bicalutamide induces only nuclear translocation of the GFP-ARER receptor (at μM concentrations). Estradiol also fails to induce visible chromatin binding, indicating androgen specificity. In a screen of reference chemicals from the EPA and the Agency for Toxic Substances and Disease Registry, the GFP-ARER cell model identified and mechanistically grouped activity by known (anti-)androgens based on the ability to induce nuclear translocation and/or chromatin binding. Finally, the cell model was used to identify potential (anti-)androgens in environmental samples in collaboration with the Houston Ship Channel/Galveston Bay Texas A&M University EPA Superfund Research Program. Based on these data, the chromatin-binding, in vitro assay-based GFP-ARER model represents a selective tool for rapidly identifying androgenic activity associated with drugs, chemicals, and environmental samples.

Trends using biological target-based assays for drug detection in complex sample matrices

In vivo, drug molecules interact with their biological targets (e.g., enzymes, receptors, ion channels, transporters), thereby eliciting therapeutic effects. Assays that measure the interaction between drugs and bio-targets may be used as drug biosensors, which are capable of broadly detecting entire drug classes without prior knowledge of their chemical structure. This Trends article covers recent developments in bio-target-based screening assays for detecting drugs associated with the following areas: illicit products marketed as dietary supplements, food-producing animals, and bodily fluids. General challenges and considerations associated with using bio-target assays are also presented. Finally, future applications of these assays for drug detection are suggested based upon current needs.

Detection of SARMs in doping control analysis

The class of selective androgen receptor modulators (SARMs) has been the subject of intense and dedicated clinical research over the past two decades. Potential therapeutic applications of SARMs are manifold and focus particularly on the treatment of conditions manifesting in muscle loss such as general sarcopenia, cancer-associated cachexia, muscular dystrophy, etc. Consequently, based on the substantial muscle- and bone-anabolic properties of SARMs, these agents constitute substances with significant potential for misuse in sport and have therefore been added to the Word Anti-Doping Agency's (WADA's) Prohibited List in 2008. Since then, numerous adverse analytical findings have been reported for various different SARMs, which has underlined the importance of proactive and preventive anti-doping measures concerning emerging drugs such as these anabolic agents, which have evidently been misused in sport despite the fact that none of these SARMs has yet received full clinical approval. In this review, analytical data on SARMs generated in the context of research conducted for sports drug testing purposes are summarized and state-of-the-art test methods aiming at intact drugs as well as diagnostic urinary metabolites are discussed. Doping control analytical approaches predominantly rely on chromatography hyphenated to mass spectrometry, which have allowed for appropriately covering the considerable variety of pharmacophores present in SARMs such as the non-steroidal representatives ACP-105, BMS-564929, GLPG0492 (DT-200), LG-121071, LGD-2226, LGD-4033/VK 5211, ostarine/enobosarm, RAD-140, S-40503, etc. as well as steroidal compounds such as MK-0773 and YK-11.

Effects of sex hormone-binding globulin (SHBG) on androgen bioactivity in vitro

Biochemical assessments of androgen status (hyper- or hypoandrogenism) are usually based on serum testosterone concentrations. According to the free hormone hypothesis, sex hormone-binding globulin (SHBG) determines free and bioavailable testosterone concentrations. Previous studies have suggested that in vitro androgen bioassay results may also be influenced by SHBG and correlate with free or bioavailable testosterone concentrations. To test this hypothesis, we established a stable HEK293 cell line with high expression of the human androgen receptor (AR) and a luciferase reporter downstream of a classical androgen response element. Importantly, we demonstrate that bioassay results are sensitive to dilution effects which increase apparent bioactivity in an SHBG-dependent manner. We therefore adopted a method using undiluted serum, which reduced cell proliferation but did not significantly affect the luciferase signal, cell viability or cytotoxicity. To correct for serum matrix effects, we applied signal correction based on internal controls with AR agonists or antagonists. Using this method, we provide direct evidence that in vitro androgen bioactivity reflects the inhibitory effects of SHBG, and correlates with free or bioavailable testosterone concentrations in adult hypogonadal men receiving androgen replacement therapy. In men receiving anti-androgens, serum bioactivity decreased tenfold while serum testosterone concentrations decreased only four-fold. Further pilot results in prostate cancer patients showed that androgen synthesis inhibitors result in more complete inhibition of androgen bioactivity than gonadorelin-based androgen deprivation therapy, even in patients whose testosterone concentrations were undetectable by mass spectrometry. We conclude that in vitro androgen reporter bioassays are useful tools to study how androgen bioactivity in serum is determined by androgens, anti-androgens as well as SHBG, provided that dilution and matrix effects are accounted for.