Corticosteroids and the blood–brain barrier

Systematic Study of Steroid Drugs' Ability to Cross Biomembranes-The Possible Environmental Impact and Health Risks Associated with Exposure During Pregnancy

Thirty-seven steroid drugs of different types were investigated in silico for their environmental and pharmacokinetic properties (partition between soil and water, bioaccumulation in aquatic organisms, ability to be absorbed from the gastrointestinal tract and to cross biological barriers-skin, blood-brain barrier and placenta) using on-line tools and novel QSAR models. The same drugs were studied by Molecular Docking in the context of their ability to interact with two enzymes-glutathione S-transferase (GST) and human N-acetyltransferase 2 (NAT2), which are involved in the placenta's protective system against harmful xenobiotics. Steroid drugs are released to the environment from households, hospitals, manufacturing plants and farms (e.g., with natural fertilizers) and they can affect the aquatic life (reproduction and development of aquatic organisms), even at sub-ng/L concentrations. It was established that the majority of studied drugs are mobile in soil, so they may reach surface waters far from point of discharge, e.g., from farming; however, only a few of them are likely to bioaccumulate. All of them can be absorbed orally or through skin, and they are also expected to cross the placenta. Over 30% of studied compounds are likely to pass through the blood-brain barrier (although five compounds in this group are likely P-gp substrates, which may reduce their activity in the central nervous systems); they have also very high affinity for both studied enzymes.

Corticosteroid-Induced Psychiatric Disorders: Mechanisms, Outcomes, and Clinical Implications

Corticosteroids are extensively used in medicine for their powerful anti-inflammatory and immunosuppressive effects. However, their psychiatric side effects-such as mood disturbances, anxiety, and psychosis-are significant yet often underappreciated. This review provides a comprehensive exploration of corticosteroid-induced psychiatric disorders, with a focus on their underlying mechanisms and clinical implications. We examine how corticosteroids influence the hypothalamic-pituitary-adrenal (HPA) axis, leading to the dysregulation of stress responses and alterations in neurotransmitter levels, particularly dopamine, serotonin, and glutamate. These changes are linked to structural abnormalities in key brain areas such as the hippocampus and amygdala, which are implicated in mood and anxiety disorders, psychosis, and conditions like post-traumatic stress disorder (PTSD) and eating disorders. This review highlights the need for healthcare providers to be vigilant in recognizing and managing corticosteroid-induced psychiatric symptoms, especially in vulnerable populations with pre-existing mental health conditions. The complex relationship between corticosteroid type, dose, duration, and mental health outcomes is explored, emphasizing the importance of personalized treatment approaches to mitigate psychiatric risks. Given the widespread use of corticosteroids, there is an urgent need for more focused research on their psychiatric side effects. This review underscores the importance of patient education and careful monitoring to ensure optimal therapeutic outcomes while minimizing mental health risks associated with corticosteroid therapy.

Dexamethasone versus methylprednisolone for multiple organ dysfunction in COVID-19 critically ill patients: a multicenter propensity score matching study

BACKGROUND

Dexamethasone usually recommended for patients with severe coronavirus disease 2019 (COVID-19) to reduce short-term mortality. However, it is uncertain if another corticosteroid, such as methylprednisolone, may be utilized to obtain better clinical outcome. This study assessed dexamethasone's clinical and safety outcomes compared to methylprednisolone.

METHODS

A multicenter, retrospective cohort study was conducted between March 01, 2020, and July 31, 2021. It included adult COVID-19 patients who were initiated on either dexamethasone or methylprednisolone therapy within 24 h of intensive care unit (ICU) admission. The primary outcome was the progression of multiple organ dysfunction score (MODS) on day three of ICU admission. Propensity score (PS) matching was used (1:3 ratio) based on the patient's age and MODS within 24 h of ICU admission.

RESULTS

After Propensity Score (PS) matching, 264 patients were included; 198 received dexamethasone, while 66 patients received methylprednisolone within 24 h of ICU admission. In regression analysis, patients who received methylprednisolone had a higher MODS on day three of ICU admission than those who received dexamethasone (beta coefficient: 0.17 (95% CI 0.02, 0.32), P = 0.03). Moreover, hospital-acquired infection was higher in the methylprednisolone group (OR 2.17, 95% CI 1.01, 4.66; p = 0.04). On the other hand, the 30-day and the in-hospital mortality were not statistically significant different between the two groups.

CONCLUSION

Dexamethasone showed a lower MODS on day three of ICU admission compared to methylprednisolone, with no statistically significant difference in mortality.

Social avoidance and altered hypothalamic-pituitary-adrenal axis in a mouse model of anxious depression: The role of LPA1 receptor

Anxious depression is a prevalent disease with devastating consequences. Despite the lack of knowledge about the neurobiological basis of this subtype of depression, recently our group has identified a relationship between the LPA1 receptor, one of the six characterized G protein-coupled receptors (LPA1-6) for lysophosphatidic acid, with a mixed depressive-anxiety phenotype. Dysfunctional social behaviors, which have been related to increased activation of the hypothalamus-pituitary-adrenal (HPA) axis, are key symptoms of depression and are even more prominent in patients with comorbid anxiety and depressive disorders. Social behavior and HPA functioning were assessed in animals lacking the LPA1 receptor. For these purposes, we first examined social behaviors in wild-type and LPA1 receptor-null mice. In addition, a dexamethasone (DEX) suppression test was carried out. maLPA1-null mice exhibited social avoidance, a blunted response to DEX administration and an impaired circadian rhythm of corticosterone levels, which are features that are consistently dysregulated in many mental illnesses including anxious depression. Here, we have strengthened the previous experimental evidence for maLPA1-null mice to represent a good animal model of anxious depression, providing an opportunity to explore new therapeutic targets for the treatment of mood disorders, particularly this subtype of depression.

Intense inhibitory avoidance training increases nuclear-phosphorylated glucocorticoid receptors in neurons of CA1 of hippocampus and ventral caudate putamen

Corticosterone (CORT), the principal glucocorticoid in rodents, is released after stressful experiences such as training with high foot-shock intensities in the inhibitory avoidance task (IA). CORT reaches the glucocorticoid receptor (GR) located in almost all brain cells; the GR is subsequently phosphorylated at serine 232 (pGRser232). This has been reported as an indicator of ligand-dependent activation of the GR, as well as a requirement for its translocation into the nucleus for its transcription factor activity. The GR is present in the hippocampus with a high concentration in CA1 and dentate gyrus (DG), and a smaller proportion in CA3, and sparsely present in the caudate putamen (CPu); both structures are involved in memory consolidation of IA. To study the participation of CORT in IA, we quantified the ratio of pGR-positive neurons in both dorsal hippocampus (CA1, CA3 and DG) and dorsal and ventral regions of CPu of rats trained in IA, using different foot-shock intensities. Brains were dissected 60 min after training for immunodetection of pGRser232 positive cells. The results show that the groups trained with 1.0 and 2.0 mA had higher retention latencies than the 0.0 mA or 0.5 mA groups. An increase in the ratio of pGR-positive neurons was found in CA1 and ventral region of CPu only for the 2.0 mA trained group. These findings suggest that activation of GRs in CA1 and ventral CPu is involved in the consolidation of a stronger memory of IA, possibly through the modulation of gene expression.

Treatment and protective effects of metalloproteinase inhibitors alone and in combination with N-Acetyl cysteine plus vitamin E in rats exposed to aflatoxin B1

This study was conducted to investigate the effects of matrix metalloproteinase (MMP) inhibitors dexamethasone and minocycline administrations -both single and in combination with N-acetylcysteine (NAC) and vitamin E-on the tissue distribution and lethal dose (LD)50 of aflatoxin (AF)B1 in rats. We performed this study on male Wistar rats (8-10 weeks) in two phases. In the first phase, rats were administered dexamethasone (5 and 20 mg/kg) and minocycline (45 and 90 mg/kg), both as single treatments and in combination with NAC (200 mg/kg) and vitamin E (600 mg/kg); these treatments followed AFB1 administration (2 mg/kg). In the second phase, the therapeutic effect value (TEV) was calculated to determine the treatment effect on the LD50 level of AFB1. The tissue affinity of AFB1 from high to low was liver, kidney, intestine, brain, heart, spleen, lung, testis, and vitreous humor, respectively. Dexamethasone at the 20 mg/kg dose significantly reduced AFB1 concentrations in the plasma and the other tissues, except for the vitreous humor. The effects of minocycline on the plasma and tissue concentrations of AFB1 varied by dose and tissue. The combinations of dexamethasone or minocycline with NAC and vitamin E increased the AFB1 concentrations in the plasma and all tissues, except for vitreous humor and liver. In male rats, the LD50 value of AFB1 was 11.86 mg/kg. The TEV of dexamethasone (20 mg/kg) was calculated to be 1.5. Dexamethasone can be administered in repeated doses at ≥20 mg/kg to increase survival in AFB1 poisoning.