Doxycycline Used for Control of Transgene Expression has its Own Effects on Behaviors and Bcl-xL in the Rat Hippocampus

The Mind Body Connection in Dermatologic Conditions: A Literature Review

Psychodermatology pertains to the relationship between the skin and brain. This review aims to summarize the evidence of the mind body connection in four psychophysiological conditions: rosacea, atopic dermatitis (AD), acne vulgaris (AV), and psoriasis. A literature search was conducted using several English language databases. All four conditions share similar psychiatric co-morbidities, including but not limited to anxiety, depression, and suicidality. In rosacea, the upregulation of transient receptor potential vanilloid type 1, Toll like receptor 2, and Th17 cells releases downstream products that are simultaneously implicated in mood disorders. Stress exacerbates AV through the hypothalamic-pituitary-adrenal (HPA) system, which alters functioning of sebocytes and Cutibacterium acnes. In AD and psoriasis, the HPA axis influences Th1, Th2, Th22, and Th1, Th17 immune mediated responses, respectively. This leads to the secretion of pro-inflammatory cytokines which are also involved in the pathogenesis of anxiety and depression. Neurotransmitters implicated in mental illness, such as gamma-aminobutyric acid and serotonin, may also play a role in the development of AD and psoriasis. The management of cutaneous disease may mitigate psychological distress, and future research may show the corollary to also be true.

[Prospects for the use of drugs with anti-inflammatory properties for the treatment of depression]

The review briefly summarizes experimental and preclinical data of the role of pro-inflammatory cytokines in triggering pathophysiological changes associated with depression, primarily major depressive disorder (MDD), as well as the possibility of using anti-inflammatory drugs as antidepressants.

Anxiogenic-like effect of chronic lipopolysaccharide is associated with increased expression of matrix metalloproteinase 9 in the rat amygdala

Pathways by which inflammatory stimuli influence behaviors can involve changes in neuronal plasticity, however, the evidence for this is still insufficient. This study aimed to evaluate the effects of chronic lipopolysaccharide (LPS) injected alone or together with tetracycline antibiotic doxycycline (Dox) on the levels of Iba-1, BDNF, Bcl-xL and MMP-9 in brain regions in relation to stress-induced behaviors in the elevated plus-maze (EPM). LPS injected to adult rats every 2 days for a total of 7 injections reduced body weight gain, increased spleen and adrenal weights, decreased locomotor activity, and increased anxiety-like behavior. These effects were associated with increased expression of Iba-1, a well-known marker for activated microglia, in most brain regions investigated. Co-treatment of LPS with Dox attenuated LPS-induced microglial activation and behavioral changes, supporting their relation to the neuroinflammation. LPS administration also produced pro-apoptotic changes in the brain. In the hypothalamus and striatum, the levels of anti-apoptotic protein Bcl-xL were decreased, whereas in the amygdala, a significant increase in MMP-9 protein levels was observed. The levels of Iba-1 as well as MMP-9 in the amygdala positively correlated with the numbers of defecation. The data suggest that mechanisms of anxiety associated with neuroinflammation may involve the increase in MMP-9 levels in the amygdala.

Genetic approaches to the investigation of serotonergic neuron functions in animals

The serotonergic system is one of the most important neurotransmitter systems that take part in the regulation of vital CNS functions. The understanding of its mechanisms will help scientists create new therapeutic approaches to the treatment of mental and neurodegenerative diseases and find out how this neurotransmitter system interacts with other parts of the brain and regulates their activity. Since the serotonergic system anatomy and functionality are heterogeneous and complex, the best tools for studying them are based on manipulation of individual types of neurons without affecting neurons of other neurotransmitter systems. The selective cell control is possible due to the genetic determinism of their functions. Proteins that determine the uniqueness of the cell type are expressed under the regulation of cell-specific promoters. By using promoters that are specific for genes of the serotonin system, one can control the expression of a gene of interest in serotonergic neurons. Here we review approaches based on such promoters. The genetic models to be discussed in the article have already shed the light on the role of the serotonergic system in modulating behavior and processing sensory information. In particular, genetic knockouts of serotonin genes sert, pet1, and tph2 promoted the determination of their contribution to the development and functioning of the brain. In addition, the review describes inducible models that allow gene expression to be controlled at various developmental stages. Finally, the application of these genetic approaches in optogenetics and chemogenetics provided a new resource for studying the functions, discharge activity, and signal transduction of serotonergic neurons. Nevertheless, the advantages and limitations of the discussed genetic approaches should be taken into consideration in the course of creating models of pathological conditions and developing pharmacological treatments for their correction.

The effects of isotretinoin on affective and cognitive functions are disparate in adolescent acne vulgaris patients

Background: The vulnerable brain regions to isotretinoin are represented as hippocampus and prefrontal cortex, involved in mood regulation as well as coordination of cognitive functions. Adolescence is a critical period with dynamic alterations in neurocognition. Isotretinoin brought concerns about its possible effects on executive functions, attention and memory.Objective: Evaluate the impacts of isotretinoin on neurocognitive functions in adolescents with acne vulgaris and determine the emergence of psychiatric side effects.Materials and methods: Fifty-five adolescent acne vulgaris patients were assigned to either isotretinoin (n = 38) or systemic antibiotic (n = 17) groups. The neuropsychological test battery and psychometric tests were performed before treatment and during treatment with 3-months intervals.Results: Stroop-TBAG form, verbal-auditory digit span, controlled oral word association test and trail making test results improved in the isotretinoin treatment group along with stable scores in the antibiotic group. Children Depression Scale scores of the isotretinoin group showed an increase at 6^th month compared to baseline. None of the patients was evaluated as depressive by the psychiatric examination.Conclusions: In a vulnerable age group, our results demonstrate an improvement for neurocognitive functions in isotretinoin patients. The conflicting results suggest distinct mechanisms to be responsible for the effects on affective and cognitive functions.