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- Stiernman, Louise, 1994-
(författare)
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Premenstrual dysphoric disorder : brain structure and function, GABAA-active neurosteroids and GABAA receptor plasticity
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Premenstrual dysphoric disorder (PMDD) is an ovarian hormone-bound disorder, characterized by mood symptoms which occur exclusively during the luteal phase of the menstrual cycle. Previous neuroimaging studies of PMDD have primarily reported functional brain differences during the luteal phase in regions of the salience network (SN), which is commonly implicated in mood and anxiety disorders. SN dysfunction may mediate affective and behavioral deficits by leading to enhanced detection and inappropriate assignment of salience to stimuli. What drives altered brain function in PMDD is unknown. However, one influential hypothesis implicates the luteal phase hormone progesterone, and in particular its neurosteroid metabolites. Progesterone-derived neurosteroids increase transmission at the g- aminobutyric acid type A (GABAA) receptor, leading to increased inhibitory tone at the neuronal level. This thesis aimed to i) investigate structural and functional characteristics of the brain in PMDD, ii) relate functional measures to levels of neurosteroids during the luteal phase, and iii) investigate how gene expression of GABAA receptor subunits is altered across the menstrual cycle in PMDD.Results In Study I, we found that women with PMDD had thinner cortices in widespread brain regions, including regions of the SN. In Studies II and III, we found that increases in functional brain measures are most prominent during the symptomatic luteal phase in regions belonging to the SN and in other networks commonly involved in the psychopathology of mood disorders. Furthermore, we could show that increased activity in key nodes of the SN was apparent in the follicular phase and related to the severity of affective symptoms experienced during the luteal phase. Additionally, in Study II, we found that functional activity in the amygdala, a key region of the SN, was differentially associated with serum levels of GABAA receptor- active neurosteroids between PMDD and controls during the luteal phase. Lastly, in Study IV, we found seminal evidence of reduced mRNA expression of the d-GABAA subunit, which imbues GABAA receptors with increased sensitivity to progesterone’s neurosteroid metabolites. Lower expression of d subunits was related to higher amygdala reactivity.Conclusion In this thesis, I provide evidence for altered structure and function in multiple brain networks, particularly the SN in PMDD. Accentuated SN dysfunction during the symptomatic luteal phase may be mediated by the amygdala, and related to abnormal deficits in the expression of neurosteroid-sensitive d- GABAA receptors in response to ovarian hormone fluctuations.
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| 2. |
- Löfgren, Magnus, 1979-
(författare)
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Behavioral effects of female sex steroid hormones : models of PMS and PMDD in Wistar rats
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background Animal models can be used to mimic human conditions of psychopathology, and also as pre-clinical models to evaluate candidate drugs. With hormonal treatment it is possible to produce behavior in the rat which corresponds to the mental symptoms of pre-menstrual syndrome (PMS), and pre-menstrual dysphoric disorder (PMDD). PMS affects 25-30 % of all women in fertile age and 3-8% are diagnosed with the more severe condition PMDD. The cardinal mental symptoms are; irritability, mood-swings, depression, anxiety, fatigue, insomnia, difficulties with concentration and memory and learning difficulties. The symptoms of PMS/PMDD occur in the luteal phase in conjunction with increasing concentrations of progesterone (P4) and P4-metabolites. In anovulatory cycles the symptoms are absent. The hormones which produce the monthly reoccurring negative symptoms on mood are foremost the neuroactive metabolites; allopregnanolone (ALLO) and tetrahydro-deoxycorticosterone (THDOC). ALLO is produced by the corpus luteum, but can also be synthesized in the brain, both ALLO and THDOC can also be released from the adrenal cortex during stress. These steroids are active on the inhibitory GABA neurotransmitter system through the GABAA receptor, and the effects are similar to that of alcohol and benzodiazepines. These steroids have strong sedative and hypnotic effects. A paradox is that some individuals seem to react with negative mood on sex steroids while all fertile women have the cyclical steroid changes during the menstrual cycle. Some individuals are more sensitive to neuroactive steroids with influences of personality, heritability and stress factors. Aims The thesis aims were to develop pre-clinical animal models of PMS/PMDD and to investigate induction of ALLO tolerance, individual sensitivity to neurosteroids and the interactions between chronic social stress and neurosteroids. Methods In these studies male and female Wistar rats were used to test steroid hormone effects on learning and memory and behaviors analogous to negative mood symptoms. This was accomplished through hormonal treatment and a subsequent withdrawal period from P4 (P4) + estradiol (E2) (PEWD), or ALLO. To assess tolerance, memory and learning in the Morris water maze (MWM) was studied. Anxiety-like behaviors were tested with the elevated plus maze (EPM), open field test (OFT), and the intruder test (IT). The EPM or OFT was used to classify the rats as high or low responders on risk-taking and explorative behavior (HR/LR). For social ranking order assessment the tube test (TT) and food competition test (FCT) were used. Chronic social stress was accomplished through co-habituation with two older rats (chronic subordination stress). In female rats the estrous cycle followed using staining of vaginal smears. Concentration of corticosterone (CORT) was measured by radio-immuno-assay (RIA). Results In the MWM ALLO pre-treatment produced tolerance to the acute negative ALLO effects. Both male and female rats showed behavioral correlations between the EPM and OFT tests, and correlations were also seen in CORT levels. Individuals with the stable trait of high risk-taking and explorative behavior (HR) were more sensitive to PEWD induction of anxiety-like behavior. These animals also showed decreased CORT levels during withdrawal. Chronic subordination stress enhanced the response to PEWD on measures of locomotor activity and social anxiety-like behavior. Conclusions It is possible to induce tolerance to the negative ALLO effects on learning and memory. The animal models of anxiety-like behavior show an individual PEWD response profile where HR rats are more sensitive. Exposure to chronic social stress enhanced the PEWD response. Hence there are both inherent and environmental factors behind the behavioral response to steroid hormones in rats.
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| 3. |
- Montagnese, Sara, et al.
(författare)
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A pilot study of golexanolone, a new GABA-A receptor-modulating steroid antagonist, in patients with covert hepatic encephalopathy
- 2021
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Ingår i: Journal of Hepatology. - : Elsevier. - 0168-8278 .- 1600-0641. ; 75:1, s. 98-107
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Tidskriftsartikel (refereegranskat)abstract
- Background & Aims: Golexanolone is a novel small molecule GABA-A receptor-modulating steroid antagonist under development for the treatment of cognitive and vigilance disorders caused by allosteric over-activation of GABA-A receptors by neurosteroids. It restored spatial learning and motor coordination in animal models of hepatic encephalopathy (HE) and mitigated the effects of intravenous allopregnanolone in healthy adults in a dose-dependent fashion. Herein, we report data on the safety, pharmacokinetics (PK) and efficacy of golexanolone in adult patients with cirrhosis.Methods: Following single/multiple ascending dose studies, adults with Child-Pugh A/B cirrhosis and abnormal continuous reaction time (CRT) on screening were randomized to 3 weeks’ dosing with golexanolone (10, 40 or 80 mg BID) or placebo. CRT, psychometric hepatic encephalopathy score (PHES), animal naming test (ANT), Epworth sleepiness scale (ESS) and electroencephalogram (mean dominant frequency [MDF]; delta+theta/alpha+beta ratio [DT/AB]) were obtained at baseline, 10, and 21 days.Results: Golexanolone exhibited satisfactory safety and PK. Baseline characteristics were similar between the 12 and 33 patients randomized to placebo or golexanolone, respectively. By prespecified analyses, golexanolone was associated with directionally favourable changes vs. placebo in ESS (p = 0.047), MDF (p = 0.142) and DT/AB (p = 0.021). All patients also showed directionally favourable changes in CRT, PHES and ANT, but with no statistical difference between golexanolone and placebo. Post hoc analyses taking into account the variability and improvement in CRT, PHES and ANT observed between screening and baseline suggested an efficacy signal by cognitive measures as well.Conclusion: Golexanolone was well tolerated and associated with improvement in cognitive performance. These results implicate GABA-A receptor-modulating neurosteroids in the pathogenesis of HE and support the therapeutic potential of golexanolone.Lay summary: Many patients with cirrhosis experience subtle but disabling cognitive problems, including sleepiness and poor attention span, that impair their ability to be gainfully employed or carry out activities of daily living. This pilot study tested the hypothesis that these problems with cognition, for which there is no approved treatment, might be improved by an experimental drug, golexanolone, designed to normalize the function of receptors which inhibit brain function. The results of this study suggest that golexanolone is well tolerated and may improve cognition, as reflected by measures of sleepiness, attention span and brain wave activity, paving the way for future larger studies of this promising experimental drug.Clinical trial registration number: EudraCT 2016-003651-30.
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