Neuroanatomical and molecular correlates of cognitive and behavioural outcomes in hypogonadal males

A study of long-term supraphysiologic-dose anabolic-androgenic steroid use on cognitive function in middle-aged men

Background: Long-term use of supraphysiologic doses of anabolic-androgenic steroids (AAS) has been associated with impaired visuospatial memory in young men but little is known about its cognitive effects in middle-aged men.Objectives: We compared cognition in middle-aged men with histories of long-term AAS use and age-matched non-users.Methods: We administered cognitive tests from the CANTAB battery to 76 weightlifters aged 37-60 years (mean [SD] 48.5 [6.5] years), of whom 51 reported at least 2 years of cumulative AAS use and 25 reported no AAS exposure.Results: We found no significant AAS user versus non-user group differences on visuospatial, verbal memory, emotional recognition, or executive function tasks (corrected p's ≥ .00089; effect sizes ≤ .5).Conclusions: Our null visuospatial task findings contrast with our prior younger cohort study (mean age 37.1 [7.1] years), in which we found impaired visuospatial task performance in people who use AAS, and with other reports of cognitive impairments in younger men use AAS. Men who use AAS may develop early visuospatial memory deficits that stabilize by middle age while middle-aged non-users' performance may "catch up" due to normal age-related visuospatial declines. Similar effects could contribute to our null findings on other tasks. Between-study cohort substance use differences or environmental factor differences that modify cognition, such as study geographical location and time of year, also could contribute to our discordant findings. Since young adult male AAS users experience increased mortality from unnatural causes, improving our understanding of AAS cognitive effects in this age group is important.

Giftedness and atypical sexual differentiation: enhanced perceptual functioning through estrogen deficiency instead of androgen excess

Syndromic autism spectrum conditions (ASC), such as Klinefelter syndrome, also manifest hypogonadism. Compared to the popular Extreme Male Brain theory, the Enhanced Perceptual Functioning model explains the connection between ASC, savant traits, and giftedness more seamlessly, and their co-emergence with atypical sexual differentiation. Overexcitability of primary sensory inputs generates a relative enhancement of local to global processing of stimuli, hindering the abstraction of communication signals, in contrast to the extraordinary local information processing skills in some individuals. Weaker inhibitory function through gamma-aminobutyric acid type A (GABAA) receptors and the atypicality of synapse formation lead to this difference, and the formation of unique neural circuits that process external information. Additionally, deficiency in monitoring inner sensory information leads to alexithymia (inability to distinguish one's own emotions), which can be caused by hypoactivity of estrogen and oxytocin in the interoceptive neural circuits, comprising the anterior insular and cingulate gyri. These areas are also part of the Salience Network, which switches between the Central Executive Network for external tasks and the Default Mode Network for self-referential mind wandering. Exploring the possibility that estrogen deficiency since early development interrupts GABA shift, causing sensory processing atypicality, it helps to evaluate the co-occurrence of ASC with attention deficit hyperactivity disorder, dyslexia, and schizophrenia based on phenotypic and physiological bases. It also provides clues for understanding the common underpinnings of these neurodevelopmental disorders and gifted populations.

Cognitive changes and brain connectomes, endocrine status, and risk genotypes in testicular cancer patients-A prospective controlled study

OBJECTIVE

Previous research has indicated cognitive decline (CD) among testicular cancer patients (TCPs), even in the absence of chemotherapy, but little is known about the underlying pathophysiology. The present study assessed changes in cognitive functions and structural brain connectomes in TCPs and explored the associations between cognitive changes and endocrine status and hypothesized risk genotypes.

METHODS

Thirty-eight newly orchiectomized TCPs and 21 healthy controls (HCs) comparable to TCPs in terms of age and years of education underwent neuropsychological testing, structural MRI, and a biological assessment at baseline and 6 months later. Cognitive change was assessed with a neuropsychological test battery and determined using a standardized regression-based approach, with substantial change defined as z-scores ≤-1.64 or ≥1.64. MRI scans and graph theory were used to evaluate changes in structural brain connectomes. The associations of cognitive changes with testosterone levels, androgen receptor gene (AR) CAG repeat length, and genotypes (APOE, COMT, and BDNF) were explored.

RESULTS

Compared with HCs, TCPs showed higher rates of substantial decline on processing speed and visuospatial ability and higher rates of substantial improvement on verbal recall and visuospatial learning (p < 0.05; OR = 8.15-15.84). Brain network analysis indicated bilateral thalamic changes in node degree in HCs, but not in TCPs (p < 0.01). In TCPs, higher baseline testosterone levels predicted decline in verbal memory (p < 0.05). No effects were found for AR CAG repeat length, APOE, COMT, or BDNF.

CONCLUSIONS

The present study confirms previous findings of domain-specific CD in TCPs following orchiectomy, but also points to domain-specific improvements. The results do not indicate changes in brain connectomes or endocrine status to be the main drivers of CD. Further studies evaluating the mechanisms underlying CD in TCPs, including the possible role of the dynamics of the hypothalamic-pituitary-gonadal axis, are warranted.

Hippocampal cellular changes in androgen deprived insulin resistant rats

Androgen deprivation can be achieved through testosterone antagonists (chemical castration) with or without orchidectomy. We use a rat model to characterize hippocampal structural and functional changes that might be associated with a subset population of androgen deprived insulin-resistant patients. Adult male Wistar rats assigned into six (6) groups: control group (distilled water/sham), orchiectomy group (bilateral orchiectomy), flutamide group (oral flutamide; 11 mg/kg body weight), diabetes group (multiple low-dose of streptozotocin (STZ; 30 mg/kg body weight intraperitoneally), orchiectomy and diabetic group (bilateral orchiectomy with 30 mg/kg body weight of STZ), and orchiectomy/diabetic/flutamide group (bilateral orchiectomy with 30 mg/kg body weight of STZ with 11 mg/kg body weight of flutamide). Animals were sacrificed at 30 and 60 days respectively. Spatial learning and working memory behavior were assessed; while total plasma; testosterone, insulin levels, and fasting blood glucose were assayed; the Homeostasis model for insulin resistance was also calculated. Histological examinations by H&E and CFV, while immunohistochemical analysis of astrocytes, P53 protein, and NSE were performed. Androgen deprived insulin-resistant state caused altered learning and cognitive behavior through decreased percentage correct alternation to an increased escape latency period. Significant bidirectional correlates exist between the hormonal profiles relative to the control group (p < 0.05), especially in the 60 days post-orchiectomy. While histological and immunohistochemical data indicate microcellular derangement. That the summate effects of androgen deprivation and impaired insulin signaling exacerbate hippocampal neurodegenerative changes that merit further studies.

Androgen deprivation therapy and risk of cognitive dysfunction in men with prostate cancer: is there a possible link?

The expansion of the indication to use androgen deprivation therapy (ADT) to treat patients with advanced or metastatic prostate cancer has dramatically increased over the recent decades, resulting in the progress of patients’ survival. However, chronic health implications can become more apparent as the number of long-term cancer survivors is expected to be increased along with the adverse effect of ADT. In particular, interest in investigating ADT, especially luteinizing hormone-releasing hormone (LHRH) agonist association with cognitive dysfunction has been growing. Previous studies in animals and humans suggest that the level of androgen decreases with age and that cognitive decline occurs with decreases in androgen. Correspondingly, some of the extensive studies using common neurocognitive tests have shown that LHRH agonists may affect specific domains of cognitive function (e.g., visuospatial abilities and executive function). However, the results from these studies have not consistently demonstrated the association because of its intrinsic limitations. Large-scale studies based on electronic databases have also failed to show consistent results to make decisive conclusions because of its heterogeneity, complexity of covariates, and possible risk of biases. Thus, this review article summarizes key findings and discusses the results of several studies investigating the ADT association with cognitive dysfunction and risk of dementia from various perspectives.

Infertility considerations in klinefelter syndrome: From origin to management

Klinefelter syndrome (KS) is defined as the presence of one or more extra "X" chromosome in a male patient. It affects approximately 1 in 600 newborn males and the most common chromosomal abnormality, leading to male hypogonadism and infertility. There is a lack of data supporting best practices for KS patients' care. In this paper we review controversial issues in KS research ranging from mechanisms of variation in KS phenotype to abnormalities resulting in reduced sperm production to successful sperm retrieval disparities after testicular sperm extraction (TESE). Translation to live birth and offspring health is also examined. Finally, medical therapies used to optimize the hormonal status and chances of fertility in KS patients are reviewed. We will also discuss the experimental spermatogonial stem cell (SSC) treatments, which are considered the future for TESE negative patients.

Male-specific features are reduced in Mecp2-null mice: analyses of vasopressinergic innervation, pheromone production and social behaviour

Deficits in arginine vasopressin (AVP) and oxytocin (OT), two neuropeptides closely implicated in the modulation of social behaviours, have been reported in some early developmental disorders and autism spectrum disorders. Mutations in the X-linked methyl-CpG-binding protein 2 (MECP2) gene are associated to Rett syndrome and other neuropsychiatric conditions. Thus, we first analysed AVP and OT expression in the brain of Mecp2-mutant mice by immunohistochemistry. Our results revealed no significant differences in these systems in young adult Mecp2-heterozygous females, as compared to WT littermates. By contrast, we found a significant reduction in the sexually dimorphic, testosterone-dependent, vasopressinergic innervation in several nuclei of the social brain network and oxytocinergic innervation in the lateral habenula of Mecp2-null males, as compared to WT littermates. Analysis of urinary production of pheromones shows that Mecp2-null males lack the testosterone-dependent pheromone darcin, strongly suggesting low levels of androgens in these males. In addition, resident-intruder tests revealed lack of aggressive behaviour in Mecp2-null males and decreased chemoinvestigation of the intruder. By contrast, Mecp2-null males exhibited enhanced social approach, as compared to WT animals, in a 3-chamber social interaction test. In summary, Mecp2-null males, which display internal testicles, display a significant reduction of some male-specific features, such as vasopressinergic innervation within the social brain network, male pheromone production and aggressive behaviour. Thus, atypical social behaviours in Mecp2-null males may be caused, at least in part, by the effect of lack of MeCP2 over sexual differentiation.

Testosterone Supplementation and Cognitive Functioning in Men-A Systematic Review and Meta-Analysis

Testosterone supplementation (TS) is assumed important for cognitive functioning in men, but conflicting results have prevented firm conclusions. The current study systematically reviewed available randomized controlled trials (RCTs) on effects of TS on cognitive functioning in men, subjected the findings to meta-analysis, and explored between-study differences as possible moderators of the effects. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, two authors independently searched for eligible records in the electronic databases of PubMed, PsycINFO, Web of Science, the Cochrane Library, Cumulative Index of Nursing and Allied Health, and Embase and determined eligibility using the following (population, intervention, comparison, outcome) criteria: population, male adults (>18 years); intervention, TS; comparison, placebo; and outcome, results of standardized neuropsychological tests. Following duplicate removal, 3873 records were screened with 92 remaining for full-text screening. Twenty-one papers reporting results of 23 independent RCTs were included, of which none treated samples of clinically hypogonadal men. The small improvement found in overall cognitive functioning (Hedges g = 0.09; CI 95%: −0.02 to 0.19) failed to reach statistical significance (P = 0.108) and approached zero when adjusting for possible publication bias (g = 0.04). The effects for the 11 individual cognitive domains did not reach statistical significance (g: −0.04 to 0.19, P: 0.061 to 0.989). Small statistically significant (P < 0.05) effects were found for five study subsets but failed to meet the fail-safe criterion. The available evidence indicates that effects of TS on cognitive functioning in men with testosterone levels within normal ranges are less robust and of insufficient magnitude to be of clinical relevance. The effects in clinically hypogonadal men remain to be investigated.