Involvement of kynurenine pathway in depressive-like behaviour induced by nandrolone decanoate in mice

Experimental studies on androgen administration in animal models: current and future perspectives

PURPOSE OF REVIEW

This review aims to report the most recent (2020-2022) experimental scientific studies conducted on animal models, in order to highlight the relevant findings on the adverse effects related to androgen administration.

RECENT FINDINGS

Forty-one studies published between January 2020 and July 2022 were selected. The majority of studies investigated the effects of one androgen, whereas only four studies analyzed the effects of two drugs. Nandrolone decanoate was the most investigated drug (20 articles), boldenone was tested in 8 articles, testosterone and stanozolol were used in 7 articles each, 17b-trenbolone, metandienone, and oxandrolone were tested in 1 article each. The articles clarify the adverse effects of androgen administration on the heart, brain, kidney, liver, reproductive and musculoskeletal systems.

SUMMARY

The main findings of this review highlight that androgen administration increases inflammatory mediators, altering different biochemical parameters. The results concerning the reversibility of the adverse effects are controversial: on the one hand, several studies suggested that by stopping the androgen administration, the organs return to their initial state; on the other hand, the alteration of different biochemical parameters could generate irreversible organ damage. Moreover, this review highlights the importance of animal studies that should be better organized in order to clarify several important aspects related to androgen abuse to fill the gap in our knowledge in this research field.

Therapeutic Use and Chronic Abuse of CNS Stimulants and Anabolic Drugs

The available evidence suggests that affective disorders, such as depression and anxiety, increase risk for accelerated cognitive decline and late-life dementia in aging individuals. Behavioral neuropsychology studies also showed that cognitive decline is a central feature of aging impacting the quality of life. Motor deficits are common after traumatic brain injuries and stroke, affect subjective well-being, and are linked with reduced quality of life. Currently, restorative therapies that target the brain directly to restore cognitive and motor tasks in aging and disease are available. However, the very same drugs used for therapeutic purposes are employed by athletes as stimulants either to increase performance for fame and financial rewards or as recreational drugs. Unfortunately, most of these drugs have severe side effects and pose a serious threat to the health of athletes. The use of performance-enhancing drugs by children and teenagers has increased tremendously due to the decrease in the age of players in competitive sports and the availability of various stimulants in many forms and shapes. Thus, doping may cause serious health-threatening conditions including, infertility, subdural hematomas, liver and kidney dysfunction, peripheral edema, cardiac hypertrophy, myocardial ischemia, thrombosis, and cardiovascular disease. In this review, we focus on the impact of doping on psychopathological disorders, cognition, and depression. Occasionally, we also refer to chronic use of therapeutic drugs to increase physical performance and highlight the underlying mechanisms. We conclude that raising awareness on the health risks of doping in sport for all shall promote an increased awareness for healthy lifestyles across all generations.

IDO/kynurenine pathway in cancer: possible therapeutic approaches

Cancer is one of the leading causes of death in both men and women worldwide. One of the main changes associated with cancer progression, metastasis, recurrence, and chemoresistance is the change in the tumor immune microenvironment, especially immunosuppression. Cancer immunosuppression appears in multiple forms, such as inhibition of immuno-stimulant cells with downregulation of immuno-stimulant mediators or through stimulation of immuno-suppressive cells with upregulation of immunosuppressive mediators. One of the most immunosuppressive mediators that approved potency in lung cancer progression is indoleamine 2,3-dioxygenase (IDO) and its metabolite kynurenine (Kyn). The current review tries to elucidate the role of IDO/Kyn on cancer proliferation, apoptosis, angiogenesis, oxidative stress, and cancer stemness. Besides, our review investigates the new therapeutic modalities that target IDO/Kyn pathway and thus as drug candidates for targeting lung cancer and drugs that potentiate IDO/Kyn pathway and thus can be cancer-promoting agents.

The Kynurenine Pathway and Polycystic Ovary Syndrome: Inflammation as a Common Denominator

Polycystic ovary syndrome (PCOS) is a complex metabolic disorder commonly seen in females of reproductive age. The pathophysiology of PCOS is multifactorial and includes dysfunction in ovarian steroidogenesis and folliculogenesis, impaired gonadotropin levels, insulin resistance, gut microbiota imbalance, genetic predisposition, and lifestyle preferences. Low-grade inflammatory conditions such as obesity and impaired glucose tolerance are common metabolic disturbances in women with PCOS. A growing body of literature suggests strong evidence rendering PCOS in close proximity with chronic inflammation as documented by high levels of serum white blood cells, C-reactive protein, and various proinflammatory cytokines seen in this condition. Inflammation seems to be the most common metabolic denominator between the kynurenine pathway and PCOS. The association of tryptophan and kynurenine pathway has already been well documented in mood disorders, neurodegenerative diseases, chronic pain conditions, and different inflammatory states. In this manuscript, we describe the influence of sex steroid hormones on different enzymes of the KP; inflammatory nature of PCOS and CRP as a marker of IDO/TDO activity; and the effects of altered gut flora in women with PCOS. This review provides a novel view of the available evidence of tryptophan and downstream metabolites in PCOS in the context of underlying inflammation.

Androgen abuse and the brain

PURPOSE OF REVIEW

The purpose of this review is to examine the recent evidence regarding the effects of exogenous androgens on the brain. Understanding these effects is of high importance, as the consequences of androgens on the reproductive and endocrine system are well documented, while fewer studies have focused on the neural and cerebral consequences of androgen use.

RECENT FINDINGS

Supraphysiological doses of androgens have been shown to contribute to neurodegeneration, decreased brain-derived neurotrophic factor, increased inflammation and decreased neuronal density in animal studies, which may correspond to changes in mood, cognition and aggression. Findings from human studies suggest that similar behavioural and cognitive deficits may occur as a result of prolonged use of androgens. Additional evidence suggests that androgen use, particularly in high doses, may contribute to brain ageing and cerebrovascular problems.

SUMMARY

Findings from recent human and animal studies indicate that androgen use likely contributes to brain alterations, which may cause the frequently observed deficits in cognitive and emotional functioning. Although exogenous testosterone in appropriate doses for therapeutic purposes likely have some neurobiological benefits for certain populations, supraphysiological doses may cause multiple mental and physical health problems, indicating a need for additional large-scale studies in humans.

Association between nandrolone and behavioral alterations: A systematic review of preclinical studies

BACKGROUND AND AIM

In recent years the expanding misuse of Nandrolone among non-athletes, particularly adolescent males is a prevalent global concern due to its adverse effects. This article provides a summary of the experimental studies to clarify the relationship between Nandrolone exposure and behavioral and cognitive performances.

MATERIALS AND METHODS

The present systematic review was conducted using PubMed, Embase and ScienceDirect databases, from 2000 to 2020, using the following key terms: Nandrolone AND Cognition, Nandrolone AND Learning, Nandrolone AND Memory, Nandrolone AND (Synaptic plasticity or Hippocampal synaptic plasticity), Nandrolone AND (Aggression or Aggressive-like behavior), Nandrolone AND (Anxiety or Anxiety-like behavior), Nandrolone AND (Depression or Depressive-like behavior).

RESULTS

33 qualified papers were selected from the 2498 sources found. Of the 33 cases, 32 (96.97%) were males while only 1 (3.03%) was female and male. From 33 selected articles 8 reported studies were related to spatial memory, 2 reported studies were related to avoidance memory, 11 studies reported information on synaptic plasticity, 11 reported studies were related to aggressive behavior, 8 reported studies were related to aggressive behavior and 6 reported studies were related to depression.

CONCLUSION

Nandrolone can change spatial ability, avoidance memory and hippocampal synaptic plasticity. Also, Nandrolone exposure produces variable effects on behavioral function such as aggression, depression and anxiety. This despite the fact that the results are contradictory. These discrepancies might be due to the differences in sex, age, dosage and treatment duration, and administration route. However, the negative results are more common than the published positive ones.

Green Tea Suppresses Brain Aging

Epidemiological studies have demonstrated that the intake of green tea is effective in reducing the risk of dementia. The most important component of green tea is epigallocatechin gallate (EGCG). Both EGCG and epigallocatechin (EGC) have been suggested to cross the blood–brain barrier to reach the brain parenchyma, but EGCG has been found to be more effective than EGC in promoting neuronal differentiation. It has also been suggested that the products of EGCG decomposition by the intestinal microbiota promote the differentiation of nerve cells and that both EGCG and its degradation products act on nerve cells with a time lag. On the other hand, the free amino acids theanine and arginine contained in green tea have stress-reducing effects. While long-term stress accelerates the aging of the brain, theanine and arginine suppress the aging of the brain due to their anti-stress effect. Since this effect is counteracted by EGCG and caffeine, the ratios between these green tea components are important for the anti-stress action. In this review, we describe how green tea suppresses brain aging, through the activation of nerve cells by both EGCG and its degradation products, and the reductions in stress achieved by theanine and arginine.

1-MT grafted carboxymethyl chitosan and its nanoparticles: Preparation, characterization and evaluation

This work aims to synthesize two novel 1-MT (1-Methyl-DL-tryptophan) grafted CMCS (carboxymethyl chitosan) polymer prodrugs CMCS-amido-1-MT and CMCS-ester-1-MT, and to further manufacture their nanoparticles for potential biomedical applications. The polymeric prodrugs are prepared by three-step chemical synthesis. The chemical structure of drugs is confirmed by FTIR and 1H-NMR. The drug loadings of the CMCS-amido-1-MT NPs and CMCS-ester-1-MT NPs are 11.43% and 10.18%, respectively. The surface morphology of the nanoparticles is spherical or nearly spherical, while the surface is smooth and the size distribution is uniform. The average particle size is both about 200 nm, while the polydispersity index is both about 0.15. The nanoparticles have a negative charge on the surface. The particle size and its distribution change little, when the two nanoparticles are tested in the simulated blood pH environment for 7 days. However, only the CMCS-ester-1-MT nanoparticles are pH-sensitive. The cell toxicity of the CMCS-ester-1-MT nanoparticles and the original drug are both in a dose- and time-dependent manner, while the nanoparticles enter cells by endocytosis. In ECA109 cells, the CMCS-ester-1-MT nanoparticles and the original drug both induce the apoptosis. CMCS-ester-1-MT NPs can activate the ATF4/CHOP pathway in endoplasmic reticulum stress, and achieve cancer suppression through mitochondrial-related apoptosis.

Theanine, Antistress Amino Acid in Tea Leaves, Causes Hippocampal Metabolic Changes and Antidepressant Effects in Stress-Loaded Mice

By comprehensively measuring changes in metabolites in the hippocampus of stress-loaded mice, we investigated the reasons for stress vulnerability and the effect of theanine, i.e., an abundant amino acid in tea leaves, on the metabolism. Stress sensitivity was higher in senescence-accelerated mouse prone 10 (SAMP10) mice than in normal ddY mice when these mice were loaded with stress on the basis of territorial consciousness in males. Group housing was used as the low-stress condition reference. Among the statistically altered metabolites, depression-related kynurenine and excitability-related histamine were significantly higher in SAMP10 mice than in ddY mice. In contrast, carnosine, which has antidepressant-like activity, and ornithine, which has antistress effects, were significantly lower in SAMP10 mice than in ddY mice. The ingestion of theanine, an excellent antistress amino acid, modulated the levels of kynurenine, histamine, and carnosine only in the stress-loaded SAMP10 mice and not in the group-housing mice. Depression-like behavior was suppressed in mice that had ingested theanine only under stress loading. Taken together, changes in these metabolites, such as kynurenine, histamine, carnosine, and ornithine, were suggested to be associated with the stress vulnerability and depression-like behavior of stressed SAMP10 mice. It was also shown that theanine action appears in the metabolism of mice only under stress loading.