Development of haematopoietic stem cells in the human embryo

Haematopoietic stem cells (HSCs) emerge during embryogenesis and maintain hematopoiesis in the adult organism. Qualitative and quantitative assessment of HSCs can only be performed functionally using the in vivo long-term repopulation assay. Due to the lack of such data, little is known about the development of HSCs in the human embryo, which is a prerequisite for the development of new therapeutic strategies. Employing the xenotransplantation assay, I have performed here the spatio-temporal mapping of HSC activity within the human embryo and have shown that human HSCs emerge first in the aorta-gonad-mesonephros (AGM) region, specifically in the ventral wall of the dorsal aorta, and only later appear in the yolk sac, liver and placenta. Human AGM region HSCs transplanted into immunodeficient mice provide long-term high-level multilineage haematopoietic repopulation. These cells, although present in the AGM region in low numbers, exhibit a very high self-renewal potential. A single HSC derived from the AGM region generates around 600 daughter HSCs in primary recipient mice, which disseminate throughout the entire recipient bone marrow and are retransplantable. These findings highlight the vast regenerative potential of the earliest human HSCs and set a new standard for in vitro generation of HSCs from pluripotent stem cells for the purpose of regenerative medicine. I have also established a preliminary immunophenotype of the earliest human HSC. These data will be useful for my future studies on the mechanisms underlying the high potency of human embryonic HSCs and on the characterisation of embryonic HSC niche

Cone beam computed tomography evaluation of maxillary sinus before and after sinus floor elevation

Publisher Copyright: © 2019 Laura Neimane et al., published by Sciendo 2019.Sinus lift surgery elevation is a procedure that requires radiological maxillary sinus evaluation and procedure planning. The condition of the maxillary sinus before and after sinus lift surgery was assessed. Sixty-five sinuses of 49 patients were included in the study. Preoperative and postoperative cone beam computed tomography (CBCT) scans were performed. The sinuses were analysed radiologically for pathological changes: mucosal thickening, ostia obstruction and accessory opening. The presence of concha bullosa in nasal cavity and septa in the maxillary sinus were recorded. The sinus volume also was measured before and after surgery. Thickened mucosa was found more often in postoperative scans than in preoperative scans (63.1% and 67.7%, respectively). Concha bullosa was found in 30 preoperative scans and in 33 postoperative scans. A correlation between mucosal thickening and ostia obstruction was found. The mean sinus volume decreased after surgery and the changes were statistically significant. In conclusion, changes of the maxillarysinus and nasal cavity can be detected with CBCT. Sinus lift surgery does not excacerebate the existing conditions of the maxillary sinus; however, there is a tendency for pathological features to increase after surgery. Sinus lift surgery is a safe surgery with regard to the maxillary sinus if performed with care.publishersversionPeer reviewe

Identification of the niche and phenotype of the first human hematopoietic stem cells

SummaryIn various vertebrate species, the dorsal aorta (Ao) is the site of specification of adult hematopoietic stem cells (HSCs). It has been observed that the upregulation of essential hematopoietic transcription factors and the formation of specific intra-aortic hematopoietic cell clusters occur predominantly in the ventral domain of the Ao (AoV). In the mouse, the first HSCs emerge in the AoV. Here, we demonstrate that in the human embryo the first definitive HSCs also emerge asymmetrically and are localized to the AoV, which thus identifies a functional niche for developing human HSCs. Using magnetic cell separation and xenotransplantations, we show that the first human HSCs are CD34+VE-cadherin+CD45+C-KIT+THY-1+Endoglin+RUNX1+CD38−/loCD45RA−. This population harbors practically all committed hematopoietic progenitors and is underrepresented in the dorsal domain of the Ao (AoD) and urogenital ridges (UGRs). The present study provides a foundation for analysis of molecular mechanisms underpinning embryonic specification of human HSCs

OVERCOMING SOCIAL ISOLATION WITH DIGITAL TECHNOLOGIES AMONG AGEING POPULATIONS DURING COVID-19

During Covid-19 social isolation has become more common worldwide, however, some groups, especially elderly people, might have experienced dramatically limited communication due to the lack of skills and access to digital technologies. In this paper, we examined if education was associated with the use of digital technologies to maintain contacts with a family, friends, other social networks and services. The survey was conducted in June-August 2020 by doing 1089 computer-assisted telephone interviews. The questions examined how people aged 50 years and older coped with socioeconomic and health-related impact of COVID-19.We used logistic regression analysis to study the association between the use of digital technologies and the level of education by gender and age. The higher the education was, the more it strongly associated with the use of digital technologies (OR 5.85; 95% CI 3.78-9.03). As expected, age was a strong explanatory factor, however, we did not find consistent age and gender differences. Among those who used digital technologies, analyses showed that overcoming social isolation was related to the education level. The conclusion of the study is that education has inevitable impact on the use of digital technologies and social contacts, however high education level is not crucial for the acquisition of information. It seems that digital technologies are important tools to prevent social isolation and are related to education that includes digital access and competencies.

EXPLORATION OF HEALTHY AGEING DETERMINANTS IN BALTIC STATES

According to the WHO, healthy ageing is characterized by such interrelated determinants as intrinsic capacity, functional ability and environment. An individual's intrinsic capacity is a powerful predictor of the future ageing process and includes 5 areas - cognitive, psychological, sensory, locomotion and vitality. Exploration of these areas can provide necessary information for therapeutic and preventive actions that can be tailored to an individual's needs, priorities and values to support participation and quality of life. The objective of this study was to evaluate and compare healthy ageing determinants of older individuals in the Baltic States. The research was based on the sample of older individuals (50 years and older) from wave 8 of the Survey of Health, Ageing and Retirement in Europe (SHARE) during the period from November 2019 to March 2020. The obtained results indicate a low level/poor results in such determinants as locomotion, sensory, vitality and functional ability (more than 50% of the respondents among the Baltic countries has poor health, various long-term illnesses, limitations in daily activities, suffer from moderate or severe pain, requires help to meet daily needs, etc.), has various behavioral risks, however has higher assessment of cognitive and psychological determinants

Effects of social isolation on mental health during Covid-19 in the context of ageing

The COVID-19 pandemic brought significant changes to the usual rhythm of life. Reduced opportunities to meet with family members and friends in a situation of heightened stress leads to increased feelings of loneliness and social isolation, as well as increases the risk of mental health problems. The aim of this paper is to evaluate the effect of social contacts on the changes in psychoemotional states in the elderly population in Latvia during the crisis caused by the COVID-19 pandemic. The analysis draws upon quantitative data collected by the Survey of Health, Ageing and Retirement in Europe within Wave 8 in Latvia (n=1207). Measurements of the frequency of social contacts were used to construct social isolation indexes. Changes of psychoemotional state, characterized by sleeping problems, nervousness, frustration during the pandemic were included as dependent variables in multinomial logistic regression models that were run to identify the effect of social isolation on psychoemotional health in the context of other factors: age, gender, perceived health status, affluence and feelings of loneliness. The results show that in the group of those aged 50+, close to one-fifth of respondents experienced the effect of the COVID-19 crisis on their mental health. The link between reduced social contacts and changes in psychoemotional states proved to be statistically significant. In the group with the highest level of social isolation, irregularities in psychoemotional health are three times higher compared to other groups.publishersversionPeer reviewe

Difference in markers of microbial translocation and cell apoptosis in HIV monoinfected and HIV/HCV coinfected patients

Funding Information: The authors thank Valentina Sondore, MD. This study was supported by National Research Programme “Biomedicine for Public Health” (BIOMEDICINE) and by corporation “Latvijas Gâze”. Publisher Copyright: © 2019 Monta Madelane et al., published by Sciendo 2019.Immune activation in human immunodeficiency virus (HIV) infection is driven by microbial translocation and in HIV patients is one of the contributors to faster progression of liver disease along with increased cell apoptosis. The aim of the study was to compare microbial translocation and apoptosis markers in HIV monoinfected and HIV/hepatitis C virus (HCV) coinfected patients, depending on HIV immune status and antiretroviral treatment (ART). We analysed data for 78 HIV monoinfected and 105 HIV/HCV coinfected patients from the Rīga East University Hospital. Lipopolysaccharide (LPS), endotoxin core antibodies (EndoCAb), cytokeratin 18 (CK18) and cyto-chrome c (Cyt-c) levels were measured. No significant difference in LPS, EndoCAb, Cyt-c levels between HIV and HIV/HCV patients was found. The CK18 level was higher in the HIV/HCV group. Correlation between CD4+ cell count and EndoCAb antibodies was found in HCV positive patients. There was a significant effect of ART on markers for EndoCAb IgA and EndoCAb IgM antibodies in the HIV monoinfected group. Correlation between CD4+ cell count and EndoCAb antibodies and LPS was found in HIV/HCV patients on ART. Coinfection with HCV can lead to more pronounced response in EndoCAb antibody production and higher levels of cell apoptosis markers, despite similar LPS levels. ART has a positive effect on immune activation.publishersversionPeer reviewe