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Introduction: Alzheimer's disease (AD) and mild cognitive impairment (MCI) are characterized by different phases of cognitive decline. In AD, there is a progressive impairment of acquired cognitive abilities while subjects with MCI show less severe cognitive disturbances. Cognitive dysfunction develops as a result of the complex interactions between multiple genetic, epigenetic, developmental, and environmental factors. Among many genes involved in cognition is the gene coding for catechol- O-methyltransferase (COMT), the enzyme responsible for the degradation of dopamine, resulting in the modulation of dopaminergic function. Therefore, COMT genetic variants were studied in various dementias characterized by cognitive loss. The aim of the study was to evaluate the possible association between COMT rs6269 and COMT rs4680 polymorphisms and cognitive decline in subjects with AD and MCI. Methods: Cognitive deterioration was assessed with the Mini-Mental State Examination (MMSE) and the Clock Drawing test (CDT) scores in 193 patients with AD and 269 subjects with MCI. COMT rs6269 and COMT rs4680 (Val158Met) were genotyped using the real-time PCR. Multiple linear regressions and Kruskal Wallis ANOVA were used to detect the association of the COMT rs6269 or COMT rs4680 genotypes with cognitive decline. Results: Multiple linear regression showed that COMT rs6269 was significantly associated with MMSE and CDT scores and these effects were affected by diagnosis and COMT rs6269 genotypes and age. In contrast, multiple linear regression revealed that COMT rs4680 was not significantly associated with MMSE or CDT scores, and the only significant effects were found for age and diagnosis. To further evaluate the effect of COMT polymorphisms on cognition, all subjects were subdivided into AA, GA, or GG genotype carriers of the COMT rs6269 or COMT rs4680, respectively, and according to MMSE or CDT scores. Carriers of the GG genotype of the COMT rs6269 had significantly (p=0.007) lower CDT scores than AA carriers, while other genotype groups did not differ significantly according to the CDT or MMSE scores. Conclusion: Although COMT rs4680 (Val158Met) was reported to be related to cognitive loss in various neuropsychiatric disorders, present results revealed a significant association between the other COMT polymorphism, rs6269, with cognitive deterioration in dementia.

Posttraumatic stress disorder (PTSD) is a severe trauma and stress-related disorder associated with different somatic comorbidities, especially cardiovascular and metabolic disorders, and with chronic low-grade inflammation. Altered balance of the hypothalamic-pituitary-adrenal (HPA) axis, cytokines and chemokines, C-reactive protein, oxidative stress markers, kynurenine pathways, and gut microbiota might be involved in the alterations of certain brain regions regulating fear conditioning and memory processes, that are all altered in PTSD. In addition to the HPA axis, the gut microbiota maintains the balance and interaction of the immune, CNS, and endocrine pathways forming the gut-brain axis. Disbalance in the HPA axis, gut-brain axis, oxidative stress pathways and kynurenine pathways, altered immune signaling and disrupted homeostasis, as well as the association of the PTSD with the inflammation and disrupted cognition support the search for novel strategies for treatment of PTSD. Besides potential anti-inflammatory treatment, dietary interventions or the use of beneficial bacteria, such as probiotics, can potentially improve the composition and the function of the bacterial community in the gut. Therefore, bacterial supplements and controlled dietary changes, with exercise, might have beneficial effects on the psychological and cognitive functions in patients with PTSD. These new treatments should be aimed to attenuate inflammatory processes and consequently to reduce PTSD symptoms but also to improve cognition and reduce cardio-metabolic disorders associated so frequently with PTSD.

Alzheimer's disease (AD) is the most prevalent form of dementia, accounting for 60-70% of all dementia cases. It is a progressive and incurable neurodegenerative disorder characterized by the amyloid beta (Aβ) peptide deposition in the amyloid plaques and accumulation of hyperphosphorylated tau protein in the neurofibrillary tangles. It affects neuronal functioning and connectivity, resulting in a progressive loss of brain functions, with the cortex and hippocampus being primarily affected. The current AD therapy is only effective in alleviating the symptoms, whereas ongoing research aims at discovering new disease-modifying treatment strategies. The neurosteroids dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) have been studied for their neuroprotective potential in AD. Although these steroid hormones are abundant in the human blood, they are also produced de novo in neurons and glial cells, where their concentration is 6-8 times higher in comparison to periphery. In our research, we have utilized both genetic and pharmacologically induced mouse model of AD. The triple-transgenic AD (3xTg-AD) mouse is one of the most appropriate animal models of AD, displaying all main histopathological and behavioral features of AD, including age-dependent development of amyloid plaques, neurofibrillary tangles and progressive cognitive decline. The 3xTg-AD mice and C57BL/6 control mice were chronically treated with DHEAS using subcutaneously intrascapulary implanted osmotic pumps. The pharmacologically induced AD model was established by intracerebroventriculary injecting the C57BL/6 mice with Aβ oligomers and chronically administered with DHEA via intraperitoneal injection. Various cognitive and behavioral tests were performed on both models and analyzed using Noldus EthoVision XT software. Upon completion of the treatments and behavioral testing, the mice were euthanized and their brains were harvested for further analysis. Our results suggest that DHEA(S) could potentially serve as a protective agent against cognitive decline and other symptomatic presentations in mouse models of AD. Nevertheless, further validation of these results is necessary and it is imperative to extend our findings to include human blood samples to investigate potential therapeutic strategies of these neurosteroids in the future.

Introduction: Parkinson's disease (PD) is the second most common neurodegenerative disorder that is characterized by the degeneration of dopaminergic neurons in the substantia nigra. Inducing an in vitro model of PD is a valuable tool for investigating the mechanisms involved in pathogenesis of disease, which is the key to identifying potential therapeutic strategies for PD. Rotenone and 6-hydroxydopamine are neurotoxins commonly used to generate the in vitro model of PD. Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), and brain-derived neurotrophic factor (BDNF) are involved in neuroprotection and neuroregeneration, while their levels decrease with age and in neurodegenerative diseases such as PD. The aim of this study was to investigate potential neuroprotective actions of these agents in an in vitro model of PD. Materials and methods: Primary mouse neurons derived from C57BL/ 6 mice embryos and rat dopaminergic N27 cell line were injured with rotenone or 6-hydroxdopamine to induce in vitro model of PD. Both cell cultures were treated with DHEA(S) and BDNF, separately and combined, 16 h before injury. Alterations in cell viability were analyzed using the MTT test while oxidative stress parameters were determined using Cellular ROS Assay Kit 2', 7'-dichlorofluorescein diacetate (DCFHDA). Fluorescent dyes Hoechst 33342 and Propidium Iodide were used for staining apoptotic and necrotic cells. Results: Induced injury by rotenone or 6- hydroxydopamine showed lower metabolic activity and higher ROS levels, while DHEA(S), BDNF showed neuroprotective effect separately or combined on both cell cultures. Conclusion: Our results suggest that DHEA(S) and BDNF may play important role in prevention and treatment of PD.

Introduction: Alzheimer´s disease (AD) is neurodegenerative disease characterized by cognitive impairment and progressive synaptic damage accompanied by neuronal loss. The causes of amyloid beta aggregation that form amyloid plaques in the pathogenesis of AD has been debated for more than 25 years and it is supposed that amyloid beta oligomers may be the toxic factors acting on a very early stage of AD. Currently available therapy provides only symptomatic treatment, while many studies of new effective drugs have so far been unsuccessful. Therefore, neurosteroids dehydroepiandrosterone (DHEA) and its sulfated form dehydroepiandrosterone sulfate (DHEAS) are of a great interest due to their potential to modulate neurogenesis, neuronal growth and differentiation, as well as neuroprotection. Materials and methods: Neuroprotective effects of DHEA and DHEAS were investigated using primary mouse neurons, isolated from C57BL/6 mice embryos, and human SH-SY5Y neuroblastoma cells simultaneously exposed to toxic amyloid beta oligomers during 24 hours. Various assays (MTT, Muse, Promega) were used to determine cell viability and underlying mechanisms, while GraphPad Prism was used to interpret the obtained results. Results: Our results demonstrated that DHEA and DHEAS exert neuroprotective actions on primary mouse neurons and SH-SY5Y cells exposed to amyloid beta oligomers, probably via anti-apoptotic mechanisms. Conclusions: These findings suggest that DHEA and DHEAS may have therapeutic effects against amyloid beta toxicity. DHEA(S) could potentially represent novel preventive and/or therapeutic agents for AD in the future. This study needs to be confirmed and extended by further in vitro research and studies using animal models and human samples.

Parkinson’s disease (PD) is a neurodegenerative disease characterized by a selective loss of dopaminergic (DA) neurons and accumulation of α- synuclein in the substantia nigra. It is considered that gene mutations, environmental factors and aging are causative factors of PD. Understanding the mechanisms involved in neurodegeneration is the key to identifying potential therapeutic strategies for PD. Neurotoxins, such as rotenone and 6- hydroxidopamine are widely used to induce in vivo and in vitro model of PD. These neurotoxins induce mitochondrial dysfunction and increase oxidative stress, which leads to neuronal degeneration and cell death by apoptosis. Neurosteroids, dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), are the most abundant steroid hormones and can be synthesized de novo in the brain. Levels of DHEA(S) decrease with age and play an important role in brain aging and neurodegeneration. Neurotrophin, brain-derived neurotrophic factor (BDNF) is also involved in neuroprotection and neuroregeneration, while decreased levels of BDNF were observed in the aging process and in neurodegenerative diseases such as PD. In this study we have investigated potential neuroprotective effects of DHEA(S) and BDNF in four different cell models: primary mouse neurons, SH-SY5Y neuroblastoma cells, PC12 and N27 cells. These cells were injured with rotenone or 6-hydroxidopamine to induce an in vitro model of PD. In addition, cells were treated with DHEA(S) and BDNF separately and combined to investigate their interactions and neuroprotective potential. The obtained results suggest that DHEA(S) and BDNF may play important role in prevention and treatment of PD.

Alzheimer´s disease (AD) is a progressive neurodegenerative disorder that accounts for about 70% of all dementia cases. The AD pathogenesis is characterized by the aggregation of amyloid β (Aβ) peptides into extracellular senile plaques, and the formation of intracellular neurofibrillary tangles by the hyperphosphorylated tau protein. Although both structures are considered to cause a significant loss of neurons and synapses, the Aβ hypothesis has been the dominant opinion for more than 25 years [1]. The intraneuronal accumulation of Aβ peptides may precede the generation of Aβ plaques and neurofibrillary tangles formation. The Aβ peptides are known to self-assemble into dimer, trimer and higher-order oligomers, which are believed to be the main source of toxicity by causing the death of neurons [2]. Since current therapy (cholinesterase inhibitors donepezil, galantamine and rivastigmine, as well as memantine, an N-methyl D-aspartate receptor antagonist) is still symptomatic, potential disease-modifying treatment strategies have been extensively investigated [3]. In addition to positive effects on overall human health, neurosteroids dehydroepiandrosterone (DHEA) and its sulfated form dehydrepiandrosterone sulfate (DHEAS) [4], as well as neurotrophin brain-derived neurotrophic factor (BDNF) [5], are of a great interest as potential therapeutic targets for AD, due to their involvement in neurogenesis, synaptic plasticity, neuronal growth, differentiation, protection, and survival. In our laboratory, cultured primary neurons derived from C57BL/6 mice were exposed to various Aβ preparations to optimize the in vitro model of AD. To investigate the potential neuroprotective actions against Aβ toxicity, primary neuronal cultures were treated with DHEA/S, BDNF and their combination and their effects on the cell viability and mechanisms of action were studied using various cell-based and biochemical assays. Our results suggesting neuroprotective effects of DHEA/S, BDNF and their combination could point to the new therapeutic interventions for this still incurable disease. However, our findings should be confirmed by further in vitro research, as well as by in vivo experiments using AD animal models and human blood samples.

Serotonergic receptors are affected in Alzheimer's disease (AD). The overall decrease in the serotonergic transmission is also observed in AD. Previous studies showed the association of polymorphisms in genes for serotonin (5HT) receptors with behavioral and psychological symptoms of dementia (BPSD). In this study, we aimed to test if individuals carrying different genotypes in 5HTR2A rs 6313 (T102C), 5HTR1B rs13212041, 5HTR6 rs1805054 (C267T), and 5HTR2C rs 3813929 (-795C/T) polymorphisms have a higher risk for development of AD. Cerebrospinal fluid (CSF) AD biomarkers, neuropsychological tests, and apolipoprotein E (APOE) haplotype were determined in 115 AD patients and 53 mildly cognitively impaired patients, while 2701 cognitively healthy individuals with determined APOE haplotype were also included. We observed that all four analyzed polymorphisms in genes for 5HT receptors showed an association with either CSF, neuropsychological or genetic biomarkers of AD. Thus, the potential of these polymorphisms as early genetic biomarkers of AD should be further investigated.

Decrease in serotonergic transmission throughout the brain is among the earliest pathological changes in Alzheimer’s disease (AD). Serotonergic receptors are also affected in AD. Polymorphisms in genes for serotonin (5HT) receptors were mostly associated with behavioral and psychological symptoms of dementia (BPSD). In this study we aimed to test if individuals carrying different genotypes in 5HTR1B rs13212041, 5HTR2A rs6313 (T102C), 5HTR2C rs3813929 (-795C/T) and 5HTR6 rs1805054 (C267T) polymorphisms have higher risk for development of AD. Study included 115 AD patients and 53 mild cognitive impairment patients with determined cerebrospinal fluid (CSF) AD biomarkers, neuropsychological tests, and apolipoprotein E (APOE) haplotype and 2701 cognitively healthy individuals with determined APOE haplotype. All four analysed polymorphisms of serotonin receptor genes showed the association with either genetic, CSF or neuropsychological biomarkers of AD. Thus, these polymorphisms deserve further investigation as potential genetic biomarkers and therapeutic targets for AD.

Vascular dementia (VaD), the second most common form of dementia, is generally underrecognized and still poorly understood disease. It develops when the brain´s blood supply is blocked or reduced, causing deprivation of oxygen and nutrients and resulting in damage and death of neurons. The brain is highly susceptible to oxidative stress, due to its richness in fatty acids sensitive to peroxidation, as well as due to high oxygen consumption and free radicals accumulation. Oxidative stress in VaD, characterized by the exacerbated production of reactive oxygen species and insufficient antioxidant defense system, increases neuronal cell abnormalities and triggers apoptosis, leading to cognitive dysfunction and dementia. Neurosteroids dehydroepiandrosterone and dehydroepiandrosterone sulfate (DHEA/S) and neurotrophin brain-derived neurotrophic factor (BDNF) have attracted the attention of researchers investigating their involvement in various brain functions such as neural survival, plasticity, cognition and behavior. The aim of this study was to investigate the protective potential of DHEA/S and BDNF in promoting neuronal survival and preventing oxidative stress caused by brain ischemia, a common characteristic of VaD. Oxygen-glucose deprivation (OGD) was performed in primary mouse neurons derived from C57BL/6 mice, and human SH-SY5Y neuroblastoma cells as in vitro model of VaD. The cells were cultured in glucose- and serum-free medium in a modular incubator chamber filled with N2. Before or after OGD, cells were treated with DHEA/S and BDNF and cell viability and oxidative stress parameters were determined. Our results suggested protective effects of DHEA/S and BDNF against oxidative damage induced by the ischemic injury in neuronal cells.

U tijeku Alzheimerove bolesti (AB) poremećeno je normalno funkcioniranje dopaminskog sustava, što se odnosi i na aktivnost monoaminooksidaze B (MAOB), enzima uključenog u razgradnju dopamina. Točnije, aktivnost MAOB je u AB-u povišena. Povećana ekspresija MAOB je uočena u hipokampusu i moždanoj kori osoba s AB-om. Primijećeno je da MAOB rs1799836 polimorfizam može utjecati na transkripciju MAOB te posljedično i na translaciju proteina te aktivnost MAOB. Naše je nedavno istraživanje pokazalo da je razina amiloida beta 1-42 mjerenog u likvoru bila značajno snižena kod nositelja A alela u MAOB rs1799836 polimorfizmu. Cilj ovog istraživanja je bila usporedba MAOB rs1799836 polimorfizma s APOE genotipom, jedinim potvrđenim genetičkim rizičnim čimbenikom za razvoj sporadične AB. Istraživanje je obuhvatilo 253 ispitanika, od koji je 127 bolovalo od AB, 57 su bili pacijenti s blagim spoznajnim poremećajem, 11 su bili zdrave kontrole, a 58 ih je bolovalo od drugih primarnih uzroka demencije. Rezultati su pokazali povišen broj pacijenata s APOE epsilon4/epsilon4 genotipom i nositelja APOE epsilon4 alela među nositeljima AA MAOB rs1799836 genotipa. Ti rezultati upućuju da bi MAOB rs1799836 polimorfizam mogao biti važan genetički biljen AB-a.

The normal functioning of dopaminergic system is compromised during Alzheimer’s disease (AD). The activity of monoamine oxidase B (MAOB), enzyme involved in degradation of dopamine, is also disturbed in AD. It was observed that MAOB activity is increased during AD. Also, increased expression of MAOB was detected in hippocampus and cortex of people who suffered from AD. It was observed that MAOB rs1799836 polymorphism can affect MAOB transcription, consequently influencing also protein translation and MAOB activity. Our recent study showed that the levels of cerebrospinal fluid amyloid β1-42 were decreased in patients carrying A allele in MAOB rs1799836 polymorphism. The goal of this study was to compare MAOB rs1799836 polymorphism with APOE, the only confirmed genetic risk factor for sporadic AD. Study included 253 participants of whom 127 suffered from AD, 57 were mild cognitive impairment patients, 11 were healthy controls and 58 suffered from other primary causes of dementia. We observed that the number of APOE ɛ4/ɛ4 homozygotes and APOE ɛ4 carriers was significantly increased among patients carrying AA MAOB rs1799836 genotype. These results indicate that the MAOB rs1799836 polymorphism could be strong genetic biomarker of AD. Acknowledgements: Supported by The Croatian Science Foundation grant IP-2019-04-3584 (“Role of blood-brain barrier, innate immunity, and tau protein oligomerization in the pathogenesis of Alzheimer's disease”) to GŠ and by the Centre of Excellence for Basic, Clinical and Translational Neuroscience CoRE-NEURO (“Experimental and clinical research of hypoxic- ischemic damage in perinatal and adult brain” ; GA KK01.1.1.01.0007 funded by the European Union through the European Regional Development Fund)

Dementia is a syndrome of progressive cognitive decline that usually affects older people. It will become one of the leading global problems in the future due to accelerated aging of the population and increase of life expectancy. Alzheimer´s disease (AD) is the most common progressive and incurable neurodegenerative disease. Neuroimaging techniques have shown a decrease in brain volume and weight in AD patients, as well as dilation of lateral brain chambers, while post-mortem studies have found extracellular accumulations of amyloid beta (Aβ) in senile plaques and intracellular neurofibrillary tangles as a result of accumulating hyperphosphorylated tau protein. Current available therapy is based on symptomatic treatment or alleviation of disease symptoms and numerous studies of new effective drugs have failed. Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), the most abundant steroids in human blood whose concentrations decrease significantly with aging, are involved in brain functions such as neural plasticity, learning, memory and behavior and have anti-inflammatory, antioxidant and anti-glucocorticoid effects. Brainderived neurotrophic factor (BDNF) is one of trophic factors that is involved in various aspects of neuronal development and differentiation, as well as plasticity and repair mechanisms. BDNF promotes the survival and differentiation of neurons that are damaged in AD. The purpose of this study is to investigate the neuroprotective potential and mechanisms of action of DHEA(S) and BDNF in dementia, through a combination of cellular, animal and human experiments. Currently, we are conducting in vitro experiments in which we study the protective effects of DHEA(S) and BDNF on isolated primary neurons from C57BL/6 mouse strain, treated with toxic Aβ-oligomers.

Sporadični oblik Alzheimerove bolesti (AD) s kasnim početkom je najčešći uzrok demencije. Mnogobrojni rizični čimbenici za AD su starija dob, različiti čimbenici iz okoline i genetski čimbenici. Ti su rizični čimbenici iz okoline odgovorni za raniji početak bolesti, bržu progresiju, jaču težinu simptoma. Uz mnoštvo rizičnih gena, gen za moždanih neurotrofni čimbenik BDNF kodira protein BDNF koji je uključen u modulaciju plastičnosti mozga, rast neurona, preživljavanje, funkciju, neurogenezu, regeneraciju, ali i apoptozu. BDNF ima ulogu i u promjenama moždanih puteva jer njegove promjene utječu na fiziologiju i neuroplastičnost. Snižene koncentracije središnjeg i perifernog BDNF-a povezane su s različitim neurodegenerativnim i psihijatrijskim poremećajima, uključujući i AD. Genske varijante BDNF-a mogu objasniti interindividualne razlike koje se javljaju u AD-u. Budući da nema izlječenja AD-a, validirani, specifični i selektivni biomarkeri povezani s endofenotipovima koji se javljaju unutar kliničke slike AD-a potrebni su, ali još uvijek nedostupni. Studija je ciljala istražiti povezanost različitih BDNF polimorfizama (rs6265, rs11030104, rs7934165, rs1519480, rs56164415) s koncentracijom biomarkera iz cerebrospinalne tekućine (CSF): amiloida beta (1-42), ukupnih tau proteina, fosforiliranih tau proteina (p-tau181, p-tau199, p- tau231) i proteina nalik vizininu (VILIP-1) u bolesnika s AD s kasnim početkom. Mogući AD (N=114) je dijagnosticiran temeljem DSM-IV i NINDS-ADRDA kriterija. Pronađena je značajna povezanost između BDNF rs11030104, rs11030104 i rs7934165 i CSF biomarkera, dok drugi polimorfizmi nisu bili povezani s CSF biomarkerima. Naime, BDNF rs6265 bio je značajno povezan s koncentracijom p-tau181, jer su nositelji A alela prema nositeljima GG imali značajno sniženu koncentraciju p-tau181. Značajna je povezanost utvrđena između BDNF rs11030104 i koncentracije p-tau181 i p-tau199, jer su nositelji GG genotipa imali značajno nižu koncentraciju p- tau181 i p-tau199 naspram nositelja AA ili AG genotipova. Uz to je pronađen tren prema odnosu između BDNF rs7934165 i koncentracije VILIP-1, budući da su nositelji AA imali nižu VILIP-1 koncentraciju prema nositeljima G alela. Naši podatci trebaju potvrdu na većim skupinama ispitanika, no ti preliminarni podatci upućuju na povezanost između BDNF genskih varijanti (rs11030104, rs11030104 i rs7934165) i CSF biomarkera koji su inače povišeni u AD, fosforiliranih tau (p-tau181 i p-tau199), te VILIP-1 proteina u bolesnika s kasnim početkom AD.

Alzheimer´s disease (AD), the most common type of dementia, is still without effective treatment. This neurodegenerative disease is characterized by progressive cognitive decline, neuronal death, as well as accumulation of amyloid beta (Aβ) senile plaques and tau neurofibrillary tangles in the brain. Neurosteroids dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), potent modulators of neurogenesis, neuronal growth, differentiation and neuroprotection, decrease with age and play an important role in brain aging and neurodegeneration. One of the possible DHEA(S) mechanisms is the modulation of brain-derived neurotrophic factor (BDNF) concentrations and tyrosine kinase receptors (Trk) for BDNF. Neurotrophin BDNF is also involved in synaptic plasticity and neuronal survival and reduced expression of BDNF in AD suggests its involvement in AD pathogenesis. However, the role of BDNF and DHEA(S), as well as their interaction in AD is not clear. Therefore, we have investigated the effects of DHEA(S) and BDNF in an in vitro model of AD with a particular focus on their interactions and their joint neuroprotective potential. Primary mouse neurons were treated with Aβ oligomers, as well as with DHEA(S) and BDNF or their combination. The obtained results suggest that DHEA(S) and BDNF may promise new options for the prevention and treatment of AD.

Alzheimer´s disease (AD) is a multifactorial neurodegenerative disorder still without effective and stable therapeutic strategies. It is characterized by the progressive cognitive decline and neuronal death, especially in the hippocampus and neocortex, which is probably due to the accumulation of beta amyloid (Aβ) plaques and neurofibrillary tangles. The etiology of AD is still not clear ; however, there are many known genetic and environmental risk factors. Brain- derived neurotrophic factor (BDNF) is the most widely distributed neurotrophic factor in the adult brain, whose levels are reduced in AD. BDNF plays an important role in synaptic plasticity, synaptogenesis, neuronal survival and growth, particullary in the hippocampus, the brain region essential for learning and memory. This study has investigated potential neuroprotective effect of BDNF in primary neuronal cultures derived from the C57BL/6 mice. Primary mouse neurons were treated with various concentrations of toxic Aβ oligomer preparations, as well as with different BDNF concentrations. The colorimetric MTT assay, Promega cell-based and biochemical assays and Muse cell analyzer were used to investigate Aβ-induced cytotoxicity, as well as neuroprotective effects of BDNF. The results demonstrated that Aβ oligomers caused necrosis and apoptosis of neuronal cells, rather than oxidative stress, presumably acting via membrane integrity disruption, as well as caspase and bcl-2 activation. The observed neuroprotective effect of BDNF alone, but also in the combination with neurosteroids dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) is, at least partly, achieved by blocking the caspase activation and suggests beneficial antiapoptotic actions of BDNF on the survival of neurons damaged in AD.

Cilj: Alzheimerova bolest (AB) je teška neurodegenerativna bolest i najčešći uzrok demencije, koji će u skoroj budućnosti zbog ubrzanog starenja stanovništva postati jedan od vodećih medicinskih, društvenih i ekonomskih problema. Terapija AB svodi se na simptomatsko liječenje, a brojne studije novih učinkovitih lijekova za sada su bezuspješne. Istraživanja pokazuju da neurosteroidi dehidroepiandrostendion (DHEA) i njegov sulfat (DHEAS), kao i neurotrofin moždani neurotrofni čimbenik (BDNF), posjeduju neuroprotektivno djelovanje i potencijal za prevenciju i liječenje AB. Međutim, njihove složene interakcije i molekularni mehanizmi djelovanja nisu u potpunosti razjašnjeni. Stoga je cilj ovog istraživanja poboljšati razumijevanje kompleksnih interakcija i mehanizama u podlozi terapijskog potencijala DHEA, DHEAS i BDNF u AB. Metode: In vitro istraživanja provedena su u primarnoj kulturi neurona, izoliranih iz embrija C57BL/6 miševa starih 15 dana. Stvaranje Aβ oligomera, koji se smatraju odgovornima za neurotoksični učinak u mozgu osoba s AB, provjereno je mikroskopijom atomskih sila (AFM) i denaturirajućom elektroforezom na poliakrilamidnom gelu (SDS-PAGE). Toksičnost Aβ oligomera u primarnoj kulturi neurona, kao i protektivni učinak tretmana s DHEA, DHEAS i BDNF, utvrđeni su kolorimetrijskim MTT testom i primjenom staničnog analizatora MUSE. Dobiveni rezultati obrađeni su u GraphPad Prism programu. Rezultati: Koncentracija preparacije Aβ oligomera od 10 μM primijenjena u trajanju od 24 sata optimalna je za izazivanje značajne toksičnosti u primarnoj kulturi neurona. S druge strane, koncentracije DHEA i DHEAS od 0, 1 μM i koncentracija od 100 ng/mL BDNF-a primijenjene u trajanju od 24 sata pokazale su najbolji neuroprotektivni učinak na neurone tretirane toksičnim Aβ oligomerima. Zaključak: Dobiveni rezultati upućuju na potencijalni neuroprotektivni učinak DHEA, DHEAS i BDNF-a u primarnoj kulturi mišjih neurona tretiranih toksičnim Aβ oligomerima. Međutim, potrebne su daljnje in vitro studije koja će razjasniti stanične i molekularne mehanizme njihovog neuroprotektivnog djelovanja, kao i istraživanja na mišjem modelu AB (3 x Tg-AD) i na uzorcima krvi oboljelih od AB, u svrhu potencijalne primjene tihneurosteroida i neurotrofina u ranom otkrivanju bolesti, kao i prevenciji i/ili liječenju simptoma AB.

Pharmacological human enhancement: attitudes and practices of students at the University of Zagreb Under the increasing pressure of everyday living, more and more people who are not affected by disease or disorders are taking drugs and substances that can enhance their physical and mental abilities, in which case we are talking about pharmacological enhancements. The student population, exposed to academic and social pressures and challenges, is vulnerable and susceptible to the use of legal and illegal substances resulting in trends of their increased use being recorded around the world. In order to detect such trends in Croatia, determine the motives and attitudes about the moral justification of such enhancements and assess information about health and social risks and ethical dilemmas that accompany such enhancements, the study was conducted on a sample of students at the University of Zagreb. In this presentation, the mentioned research and some of its selected results will be presented. The results indicate that in most cases students are aware of the existence of such practices, while the number of students who stated that they used some of the substances for the purpose of enhancement, from a sample of 917 subjects is still below the number detected in different countries.

Neurosteroids dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), the most abundant steroids in human blood, are also synthesized de novo in the brain, where they participate in varios functions such as neural plasticity, learning, memory and behavior. Dementia is a syndrome of progressive cognitive decline, with Alzheimer´s disease (AD) and vascular dementia (VaD), as the most common forms. AD is neurodegenerative disorder characterized by the abnormal deposition of the amyloid β (Aβ) peptide and accumulation of neurofibrillary tangles, and is associated with multiple pathophysiologic mechanisms including apoptosis and oxidative stress. VaD is due to the reduced blood flow, resulting in insufficient supply of nutrients and oxygen to the brain, leading to an impairment of memory and cognitive functions. We have investigated potential neuroprotective effects of these neurosteroids in primary mouse neurons, as well as in the SH-SY5Y neuroblastoma cells. As in vitro models of AD and VaD, we have exposed these cells to the toxic Aβ oligomers, hydrogen peroxide (H2O2) inducing oxidative stress, or to the oxygen-glucose deprivation (OGD). The obtained results demonstrated the beneficial effects of DHEA and DHEAS treatment on the cell survival and viability, suggesting potential neuroprotective actions of these neurosteroids in AD and VaD.