Firing Alterations of Neurons in Alzheimer's Disease: Are They Merely a Consequence of Pathogenesis or a Pivotal Component of Disease Progression?

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder, yet its underlying causes remain elusive. The conventional perspective on disease pathogenesis attributes alterations in neuronal excitability to molecular changes resulting in synaptic dysfunction. Early hyperexcitability is succeeded by a progressive cessation of electrical activity in neurons, with amyloid beta (Aβ) oligomers and tau protein hyperphosphorylation identified as the initial events leading to hyperactivity. In addition to these key proteins, voltage-gated sodium and potassium channels play a decisive role in the altered electrical properties of neurons in AD. Impaired synaptic function and reduced neuronal plasticity contribute to a vicious cycle, resulting in a reduction in the number of synapses and synaptic proteins, impacting their transportation inside the neuron. An understanding of these neurophysiological alterations, combined with abnormalities in the morphology of brain cells, emerges as a crucial avenue for new treatment investigations. This review aims to delve into the detailed exploration of electrical neuronal alterations observed in different AD models affecting single neurons and neuronal networks.

Glioblastoma research on zebrafish xenograft models: a systematic review

Glioblastoma (GBM) constitutes the most common primary brain tumor in adults. The challenges in GBM therapeutics have shed light on zebrafish used as a promising animal model for preclinical GBM xenograft studies without a standardized methodology. This systematic review aims to summarize the advances in zebrafish GBM xenografting, compare research protocols to pinpoint advantages and underlying limitations, and designate the predominant xenografting parameters. Based on the PRISMA checklist, we systematically searched PubMed, Scopus, and ZFIN using the keywords "glioblastoma," "xenotransplantation," and "zebrafish" for papers published from 2005 to 2022, available in English. 46 articles meeting the review criteria were examined for the zebrafish strain, cancer cell line, cell labeling technique, injected cell number, time and site of injection, and maintenance temperature. Our review designated that AB wild-type zebrafish, Casper transparent mutants, transgenic Tg(fli1:EGFP), or crossbreeding of these predominate among the zebrafish strains. Orthotopic transplantation is more commonly employed. A number of 50-100 cells injected at 48 h post-fertilization in high density and low infusion volume is considered as an effective xenografting approach. U87 cells are used for GBM angiogenesis studies, U251 for GBM proliferation studies, and patient-derived xenograft (PDX) to achieve clinical relevance. Gradual acclimatization to 32-33 °C can partly address the temperature differential between the zebrafish and the GBM cells. Zebrafish xenograft models constitute valuable tools for preclinical studies with clinical relevance regarding PDX. The GBM xenografting research requires modification based on the objective of each research team. Automation and further optimization of the protocol parameters could scale up the anticancer drug trials.

Cell replacement therapy with stem cells in multiple sclerosis, a systematic review

Multiple sclerosis (MS) is a chronic inflammatory, autoimmune, and neurodegenerative disease of the central nervous system (CNS), characterized by demyelination and axonal loss. It is induced by attack of autoreactive lymphocytes on the myelin sheath and endogenous remyelination failure, eventually leading to accumulation of neurological disability. Disease-modifying agents can successfully address inflammatory relapses, but have low efficacy in progressive forms of MS, and cannot stop the progressive neurodegenerative process. Thus, the stem cell replacement therapy approach, which aims to overcome CNS cell loss and remyelination failure, is considered a promising alternative treatment. Although the mechanisms behind the beneficial effects of stem cell transplantation are not yet fully understood, neurotrophic support, immunomodulation, and cell replacement appear to play an important role, leading to a multifaceted fight against the pathology of the disease. The present systematic review is focusing on the efficacy of stem cells to migrate at the lesion sites of the CNS and develop functional oligodendrocytes remyelinating axons. While most studies confirm the improvement of neurological deficits after the administration of different stem cell types, many critical issues need to be clarified before they can be efficiently introduced into clinical practice.

Cellular Localization of Orexin 1 Receptor in Human Hypothalamus and Morphological Analysis of Neurons Expressing the Receptor

The orexin system is related to food behavior, energy balance, wakefulness and the reward system. It consists of the neuropeptides orexin A and B, and their receptors, orexin 1 receptor (OX1R) and orexin 2 receptor (OX2R). OX1R has selective affinity for orexin A, and is implicated in multiple functions, such as reward, emotions, and autonomic regulation. This study provides information about the OX1R distribution in human hypothalamus. The human hypothalamus, despite its small size, demonstrates a remarkable complexity in terms of cell populations and cellular morphology. Numerous studies have focused on various neurotransmitters and neuropeptides in the hypothalamus, both in animals and humans, however, there is limited experimental data on the morphological characteristics of neurons. The immunohistochemical analysis of the human hypothalamus revealed that OX1R is mainly found in the lateral hypothalamic area, the lateral preoptic nucleus, the supraoptic nucleus, the dorsomedial nucleus, the ventromedial nucleus, and the paraventricular nucleus. The rest of the hypothalamic nuclei do not express the receptor, except for a very low number of neurons in the mammillary bodies. After identifying the nuclei and neuronal groups that were immunopositive for OX1R, a morphological and morphometric analysis of those neurons was conducted using the Golgi method. The analysis revealed that the neurons in the lateral hypothalamic area were uniform in terms of their morphological characteristics, often forming small groups of three to four neurons. A high proportion of neurons in this area (over 80%) expressed the OX1R, with particularly high expression in the lateral tuberal nucleus (over 95% of neurons). These results were analyzed, and shown to represent, at the cellular level, the distribution of OX1R, and we discuss the regulatory role of orexin A in the intra-hypothalamic areas, such as its special role in the plasticity of neurons, as well as in neuronal networks of the human hypothalamus.

Prevalence of Alcohol Use Disorders and Their Association with Sociodemographic Determinants and Depression/Anxiety Disorders in a Representative Sample of the Greek General Population

BACKGROUND

Country-level epidemiological data about alcohol-related problems is useful for planning prevention and treatment services. Heavy Alcohol Consumption (HAC) and Alcohol Use Disorder (AUD) are two syndromes of alcohol-related problems that have been recognized worldwide. Study of the epidemiological determinants of HAC and AUD in different sociocultural contexts could inform hypotheses about the etiology or the consequences of alcohol-related problems.

OBJECTIVES

We assessed the prevalence and associations of HAC and AUD with sociodemographic variables adjusting for common mental disorders in a representative sample of the general population of Greece (N = 4894 participants). The period of data collection just preceded the emergence of the financial crisis in Greece.

RESULTS

The majority of the population did not report HAC, AUD or abstinence from alcohol. HAC was reported by 12.7% (95% CI: 11.8-13.6) of the population while 3.1% (95% CI: 2.7-3.6) met criteria for AUD. Younger age, divorce, lower educational level, living in an urban area, physical health problems, and smoking were associated with a higher prevalence of both conditions. Presence of severe financial difficulties and never married family status were associated with a higher prevalence of HAC but not AUD. HAC was associated with nonspecific psychiatric morbidity while AUD was associated with more specific psychiatric disorders. Conclusion/Importance. Both alcohol-related problems are frequent in the general population and have common and distinct determinants. The comparison between the findings of our study and those of similar studies during or after the period of financial austerity in Greece, would offer the opportunity to assess the possible effects of changes in the economical context in the determinants of alcohol-related problems.

Factor analysis and normative scores of Alcohol Use Disorders Identification Test (AUDIT) in a representative sample of the general population of Greece

The most widely used screening instrument for alcohol use disorders (AUD) is the Alcohol Use Disorders Identification Test (AUDIT) which, although initially developed for use in primary care, is increasingly used in general population studies. Previous studies that have assessed the screening properties and the factorial structure of AUDIT were mostly based on clinical samples and did not take into consideration the possible differences in AUDIT factorial properties between subgroups according to age, sex and mental health status. Aim of the current study was to explore the distribution of AUDIT and AUDIT-Consumption (AUDIT-C) scores and the factorial structure of AUDIT in subgroups of participants according to sex, age and the presence of mental health disorder. Descriptive statistics and Exploratory/Confirmatory Factor Analysis of AUDIT were extracted in a general population representative sample of 4,894 Greek participants. Different cut-offs are suggested in order to screen 10% of the population with the highest severity of AUD into the aforementioned subgroups. Generally, a cut-off between 10-12 at AUDIT score is suggested for screening the 10% with the highest severity of alcohol use problems in subgroups of frequent alcohol consumers (e.g. younger males) and a cut-off between 4-5 would screen the 5% with the highest severity of alcohol use problems in subgroups of low alcohol-consumers (e.g. older women). A cut-off of 3 in AUDIT-C score is suggested for screening 25% of individuals with the heaviest alcohol consumption. The traditional three-factor model does not explain better the factorial structure of AUDIT compared to the 2-factors model. The AUDIT is a reliable instrument for assessing AUD and heavy alcohol consumption in the Greek general population. Age, sex and the presence of mental health disorders should be taken into consideration when selecting cut-offs for screening purposes in non-clinical samples.

Longitudinal association between different levels of alcohol consumption and a new onset of depression and generalized anxiety disorder: Results from an international study in primary care

BACKGROUND

Several studies that have examined the full range of alcohol consumption have pointed to a possible non-linear association between alcohol use and the common mental disorders. Most of these studies are cross sectional and assessed psychiatric morbidity using non-specific instruments. Our aim was to investigate the longitudinal association between varying levels of alcohol consumption at baseline and the new-onset of depression and generalized anxiety disorder (GAD), in a large international primary care sample.

METHODS

The sample consisted of 3201 primary care attenders from 14 countries in the context of WHO Collaborative Study of Psychological Problems in General Health Care. Alcohol use at baseline was assessed using AUDIT and the mental disorders were assessed with the Composite International Diagnostic Interview.

RESULTS

Light to moderate alcohol consumption at baseline was associated with a lower incidence of depression and GAD compared to abstinence while excessive alcohol consumption was associated with a higher incidence of depression but not GAD. This non-linear association was not substantially affected after adjustment for a range of possible confounding variables.

CONCLUSION

Any causal interpretation of this association is difficult in the context of an observational study and further combined and consistent evidence from different sources is needed.

Depression in late adolescence: a cross-sectional study in senior high schools in Greece

BACKGROUND

Depression is a common mental health problem in adolescents worldwide. The aim of the present study was to investigate the prevalence, comorbidity and sociodemographic and socioeconomic associations of depression and depressive symptoms, as well as the relevant health services use in a sample of adolescents in Greece.

METHODS

Five thousand six hundred fourteen adolescents aged 16-18 years old and attending 25 senior high schools were screened and a stratified random sample of 2,427 were selected for a detailed interview. Psychiatric morbidity was assessed with a fully structured psychiatric interview, the revised Clinical Interview Schedule (CIS-R). The use of substances, such as alcohol, nicotine and cannabis, and several sociodemographic and socioeconomic variables have been also assessed.

RESULTS

In our sample the prevalence rates were 5.67 % for the depressive episode according to ICD-10 and 17.43 % for a broader definition of depressive symptoms. 49.38 % of the adolescents with depressive episode had at least one comorbid anxiety disorder [OR: 7.76 (5.52-10.92)]. Only 17.08 % of the adolescents with depression have visited a doctor due to a psychological problem during the previous year. Anxiety disorders, substance use, female gender, older age, having one sibling, and divorce or separation of the parents were all associated with depression. In addition, the presence of financial difficulties in the family was significantly associated with an increased prevalence of both depression and depressive symptoms.

CONCLUSIONS

Prevalence and comorbidity rates of depression among Greek adolescents are substantial. Only a small minority of depressed adolescents seek professional help. Significant associations with financial difficulties are reported.

Cross-cultural patterns of the association between varying levels of alcohol consumption and the common mental disorders of depression and anxiety: secondary analysis of the WHO Collaborative Study on Psychological Problems in General Health Care

BACKGROUND

Alcohol consumption is associated with several complications of both physical and mental health. Light or moderate alcohol consumption may have beneficial effects on physical or mental health but this effect is still controversial and research in the mental health field is relatively scarce. Our aim was to investigate the association between varying levels of alcohol consumption and the common mental disorders of depression and anxiety in a large international primary care sample.

METHODS

The sample consisted of 5438 primary care attenders from 14 countries who participated in the WHO Collaborative Study of Psychological Problems in General Health Care. Alcohol use was assessed using Alcohol Use Disorders Identification Test (AUDIT) and the mental disorders were assessed with the Composite International Diagnostic Interview (CIDI).

RESULTS

Light to moderate alcohol consumption was associated with a lower prevalence of depression and generalized anxiety disorder compared to abstinence while excessive alcohol consumption was associated with a higher prevalence of depression. This non-linear association was not substantially affected after adjustment for a range of possible confounding variables, including the presence of chronic disease and the current physical status of participants and was evident in different drinking cultures.

CONCLUSION

The study confirms that excessive drinking is associated with an increased prevalence of depression, but also raises the possibility that light/moderate drinking may be associated with a reduced prevalence of both depression and anxiety. Any causal interpretation of this association is difficult in the context of this cross-sectional study and further longitudinal studies are needed.

Prevalence and sociodemographic associations of common mental disorders in a nationally representative sample of the general population of Greece

BACKGROUND

No study in Greece has assessed so far the full range of common mental disorders using a representative sample of the population from both mainland and insular regions of the country. The aim of the present paper was to present the results of the first such study.

METHODS

The study was carried out between 2009-2010 in a nationally representative sample of 4894 individuals living in private households in Greece. Common mental disorders in the past week were assessed with the revised Clinical Interview Schedule (CIS-R). We also assessed alcohol use disorders (using AUDIT), smoking and cannabis use.

RESULTS

14% of the population (Male: 11%, Female: 17%) was found to have clinically significant psychiatric morbidity according to the scores on the CIS-R. The prevalence (past seven days) of specific common mental disorders was as follows: Generalized Anxiety Disorder: 4.10% (95% CI: 3.54, 4.65); Depression: 2.90% (2.43, 3.37); Panic Disorder: 1.88% (1.50, 2.26); Obsessive-Compulsive Disorder: 1.69% (1.33, 2.05); All Phobias: 2.79% (2.33, 3.26); Mixed anxiety-depression: 2.67% (2.22, 3.12). Harmful alcohol use was reported by 12.69% of the population (11.75, 13.62). Regular smoking was reported by 39.60% of the population (38.22, 40.97) while cannabis use (at least once during the past month) by 2.06% (1.66, 2.46). Clinically significant psychiatric morbidity was positively associated with the following variables: female gender, divorced or widowed family status, low educational status and unemployment. Use of all substances was more common in men compared to women. Common mental disorders were often comorbid, undertreated, and associated with a lower quality of life.

CONCLUSIONS

The findings of the present study can help in the better planning and development of mental health services in Greece, especially in a time of mental health budget restrictions.

Bullying behaviour in schools, socioeconomic position and psychiatric morbidity: a cross-sectional study in late adolescents in Greece

BACKGROUND

Bullying is quite prevalent in the school setting and has been associated with the socioeconomic position and psychiatric morbidity of the pupils. The aim of the study was to investigate the association between bullying and socioeconomic status in a sample of Greek adolescents and to examine whether this is confounded by the presence of psychiatric morbidity, including sub-threshold forms of illness.

METHODS

5,614 adolescents aged 16-18 years old and attending 25 senior high schools were screened and a stratified random sample of 2,427 were selected for a detailed interview. Psychiatric morbidity was assessed with a fully structured psychiatric interview, the revised Clinical Interview Schedule (CIS-R), while bullying was assessed with the revised Olweus bully/victim questionnaire. The following socio-economic variables were assessed: parental educational level and employment status, financial difficulties of the family and adolescents' school performance. The associations were investigated using multinomial logit models.

RESULTS

26.4% of the pupils were involved in bullying-related behaviours at least once monthly either as victims, perpetrators or both, while more frequent involvement (at least once weekly) was reported by 4.1%. Psychiatric morbidity was associated with all types of bullying-related behaviours. No socioeconomic associations were reported for victimization. A lower school performance and unemployment of the father were significantly more likely among perpetrators, while economic inactivity of the mother was more likely in pupils who were both victims and perpetrators. These results were largely confirmed when we focused on high frequency behaviours only. In addition, being overweight increased the risk of frequent victimization.

CONCLUSIONS

The prevalence of bullying among Greek pupils is substantial. Perpetration was associated with some dimensions of adolescents' socioeconomic status, while victimization showed no socioeconomic associations. Our findings may add to the understanding of possible risk factors for bullying behaviours in adolescence.

Health related quality of life in patients with anogenital warts

INTRODUCTION

The health-related quality-of-life (HRQoL) instruments are an important tool for the evaluation of medical outcomes. Sexually transmitted diseases (STDs) influence the patients' life. We aimed to evaluate the HRQoL in patients with anogenital warts at the time of and 1 month after the diagnosis.

MATERIALS AND METHODS

We used the short-form (SF)-36 questionnaire to compare the HRQoL of 91 patients with anogenital warts to 53 control subjects with the same socioeconomic characteristics.

RESULTS

There was no statistical difference in the overall HRQoL measurement between the anogenital wart patients and controls. However, there was an improvement in the scales of vitality (65.22 ± 15.70 vs. 69.04 ± 14.11, respectively; p < 0.05) and mental health (65.00 ± 20.09 vs. 69.43 ± 18.08, respectively; p < 0.05) in anogenital warts patients between the time of diagnosis and 1 month later. Furthermore, there was a significant deterioration in the scale of social functioning (73.47 ± 22.18 vs. 72.89 ± 19.28, respectively; p < 0.05). The small sample size is a limitation of our study.

CONCLUSIONS

HRQoL does not appear to be influenced in anogenital wart patients, as measured by the generic instrument SF-36. It is therefore important to develop specific instruments for the measurement of HRQoL in this group of patients.

An empirical investigation of the structure of anxiety and depressive symptoms in late adolescence: cross-sectional study using the Greek version of the revised Clinical Interview Schedule

Several studies in the past have examined whether the hierarchical structure of anxiety and depressive symptoms can explain the high comorbidity between them but more studies are needed from other settings and with different methods. The present study aimed to examine the structure of common anxiety and depressive symptoms in adolescents 16-18 years old attending secondary schools using the Greek version of the revised Clinical Interview Schedule (CIS-R), a fully structured psychiatric interview. A total of 2431 adolescents were interviewed with the computerized version of the CIS-R. The hierarchical structure of 12 depressive and anxiety symptoms was examined with confirmatory factor analytical methods. Four alternative models of increasing complexity were tested. The best-fitting model included three first-order factors, representing the dimensions of anxiety, depression and non-specific distress respectively. A model with a higher-order factor representing the broader internalizing dimension was less supported by the data. The findings of this and other studies should be taken into account in future classifications of psychiatric disorders and may have clinical practical implications.

Socioeconomic inequalities in general and psychological health among adolescents: a cross-sectional study in senior high schools in Greece

BACKGROUND

Socioeconomic health inequalities in adolescence are not consistently reported. This may be due to the measurement of self-reported general health, which probably fails to fully capture the psychological dimension of health, and the reliance on traditional socio-economic indicators, such as parental education or occupational status. The present study aimed at investigating this issue using simple questions to assess both the physical and psychological dimension of health and a broader set of socioeconomic indicators than previously used.

METHODS

This was a cross-sectional survey of 5614 adolescents aged 16-18 years-old from 25 senior high schools in Greece. Self-reported general and psychological health were both measured by means of a simple Likert-type question. We assessed the following socio-economic variables: parents' education, parents' employment status, a subjective assessment of the financial difficulties experienced by the family and adolescents' own academic performance as a measure of the personal social position in the school setting.

RESULTS

One out of ten (10%) and one out of three (32%) adolescents did not enjoy good general and psychological health respectively. For both health variables robust associations were found in adolescents who reported more financial difficulties in the family and had worse academic performance. The latter was associated with psychological health in a more linear way. Father's unemployment showed a non-significant trend for an association with worse psychological health in girls only.

CONCLUSIONS

Socioeconomic inequalities exist in this period of life but are more easily demonstrated with more subjective socioeconomic indicators, especially for the psychological dimension of health.

No debt for medical students in Greece

BACKGROUND

Medical education in Greece is government-funded by constitution. Tuition fees are therefore not payable by students. This investigation aims to identify the sources of income of medical students in Greece.

METHODS

This is a questionnaire-based analysis of a sample of 488 students who were asked to state their sources of income.

RESULTS

Mean contributions to total student income are parental financial support (93.2%), part-time employment (2.4%), scholarships (2.5%) and other sources including loans (1.9%).

CONCLUSION

The income of medical students in Greece is mostly dependent on parental contributions. Other sources do not represent popular options. This situation differs to that in other countries, where loans make significant contributions to the total income of medical students.