HIV-1 subtypes distribution and resistance to ART in HIV-infected persons in Slovakia (2019-2021).

AIM: The aim of the study was to describe the prevalence of HIV-1 subtypes and HIV-1 strains resistant to antiretroviral therapy (ART) in HIV-positive persons newly diagnosed in Slovakia in 2019-2021. MATERIALS AND METHODS: The study group consisted of 184 HIV-positive naïve patients newly diagnosed in Slovakia from 2019 to 2021. The viral HIV-1 RNA was isolated from plasma by the QIAamp Viral RNA Mini Kit (QIAGEN, Germany). For RT-PCR and sequencing of the HIV pol region, in-house procedures were used according to the ANRS AC11 protocol for RT (reverse transcriptase), PRO (protease), and IN (integrase) [ANRS AC11 Resistance Study Group, 2015]. Analysis of sequences was performed using Sequencing Analysis Software v5.3 (Applied Biosystems®). HIV sequences were manually edited using BioEdit (version 7.2.5), compared with consensus HIV-1 sequences in the Los Alamos Sequence Database (URL 2), aligned using CLUSTAL W [Labarga et al., 2007] and BioEdit software packages (version 7.2 .5) [Hall, 1999]. HIVDB Algorithm (version 9.0) of the Stanford HIV Drug resistance database (URL 1.) was used for sequence evaluation. For HIV-1 subtype analysis, the REGA HIV-1 Subtyping Tool [De Oliviera et al., 2005] and phylogenetic analysis MEGA X [Kumar et al., 2018] were used. RESULTS: Phylogenetic analyses performed in samples of 184 persons revealed the most prevalent subtype B (129/184, 70.11%), detected to the greatest extent in the population of men who have sex with men (MSM) (96/129 74.42%). Concerning non-B subtypes (55/184, 29.89%), subtype A was found with the highest prevalence (48/184, 26.09%) compared to subtype F (F1) (3; 1.63%), C (1; 0.54%) and circulating recombinant forms CRF02_AG (2; 1.09%), CRF01_AE (1; 0.54%). In 9.24% (17/184) of samples, 25 mutations clinically relevant and associated with HIV resistance ART were detected, of which 7.07% (13/184) to reverse transcriptase inhibitors, 1.66% (3/181) to protease inhibitors and 1.32% (2/151) to integrase inhibitors. In addition, multiclass resistance was present in 1.63% (3/184) of patients. Mutations associated with HIV resistance to ART were found in 9.30 % of persons infected with subtype B. CONCLUSION: Our study confirmed ongoing highest prevalence of subtype B with a slightly decreasing trend compared to last years. Detection of mutations causing HIV resistance to ART underlines the need for resistance testing in naïve patients even before the initiation of ART in Slovakia.

Activation of the ER stress and calcium signaling in angiomyolipoma.

Renal angiomyolipomas (AMLs) are uncommon benign tumors that occur sporadically or as a part of tuberous sclerosis complex (TSC). Risk of life threatening hemorrhage is the main clinical concern. Although several evidences suggest that hyper-activation of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway is crucial for these tumors, modulation of other metabolic pathways might affect tumor growth and progression. Therefore, we aimed to further characterize angiomyolipoma by TSC1/TSC2 expression, hypoxic status, expression of endoplasmic reticulum (ER) stress markers and calcium transport from the ER through the inositol 1,4,5-trisphosphate (IP3) receptors. Despite our expectations, angiomyolipoma were not hypoxic, as determined by absent expression of the carbonic anhydrase IX, which is a reliable marker of hypoxia. This was in accord with very low expression of TSC1 (that is associated with HIF activation) and a high expression of TSC2. Angiomyolipoma specimens also showed a significant upregulation of an anti-apoptotic marker Bcl2 when compared to healthy kidney tissue supporting the induction of pro-survival signaling. Moreover, angiomyolipoma specimens showed the overexpression of the ER stress markers XBP1, CHOP and ATF4 as well as of the mediators of calcium metabolism, namely the type 1 and 2, but not the type 3 IP3 receptors. These data suggest that the ER stress response, survival and calcium metabolism-related pathways but not hypoxia is an important component of the angiomyolipoma pathogenesis.

Endosialin: molecular and functional links to tumor angiogenesis.

Endosialin, alternatively named tumor endothelial marker 1 (TEM1) or CD248, is a bulk transmembrane glycoprotein expressed both in developing and adult tissues undergoing active physiological or pathological angiogenesis. Endosialin is often overexpressed in tumors, particularly in stromal cells and in vessels-covering pericytes, and its transcription is induced by hypoxia via HIF-2 transcription factor. Based on the expression pattern, molecular characteristics and phenotypes of genetic models, endosialin has been proposed to function as a receptor implicated in sprouting angiogenesis, vasculogenesis and/or pruning of vessels. Here we provide an overview of the recent knowledge linking endosialin to diverse aspects of angiogenesis. Based on data-mining, our experimental data and available literature, we suggest that endosialin cross-talks with both pro- and anti-angiogenic signals and ECM components, and participates in dynamic vascular remodeling, which facilitates tumor growth. Tumor-selective targeting of endosialin may therefore contribute to improvement of existing anti-angiogenic therapies.

[Tumour Hypoxia -  Molecular Mechanisms and Clinical Relevance]. / Nádorová hypoxia -  molekulárne mechanizmy a klinický význam.

Oxygen is absolutely essential for correct functioning of living organisms and alterations in its concentration lead to serious consequences. In tumor tissues, oxygen plays an important role in energy production and modulation of red- ox balance. Insufficient oxygen supply within tissues results in hypoxia that is a characteristic feature of the tumor microenvironment. Hypoxia- inducible transcriptional factor represents a key executor of a cellular and molecular response to hypoxia and can activate the expression of more than hundred genes involved in various essential cellular processes. From the clinical point of view, phenotypic alterations caused by hypoxia are serious. Tumor hypoxia has been associated with resistance to therapy, disease progression and recurrence as well as increased mortality. Therefore, intratumoral hypoxia represents a clinically relevant problem, and its detection within tumors is very important for patient stratification for a suitable treatment. Currently available strategies directed towards the detection of hypoxic regions within tumor tissue suffer from numerous limitations e. g. invasiveness, inaccessibility of tumor tissue, low sensibility, inaccurate interpretation etc. On the other hand, the use of an intrinsic endogenous hypoxic marker, which can be detected through immunohistochemistry, is relatively simple, routinely available, and reproducible and can be performed on both prospective and retrospective samples. These include carbonic anhydrase IX (CA IX), one of the most strongly hypoxia-induced proteins and a prominent indicator of chronic hypoxia. Moreover, hypoxia-induced proteins (including CA IX) are also potential targets of anticancer therapy, and their practical application is a subject of intense research.

Genetic subtypes of HIV type 1 circulating in Slovakia.

Slovakia belongs to the group of European countries with a low prevalence of HIV infection. The major proportion of HIV-positive cases in Slovakia is still represented by MSM, followed by heterosexuals infected through unprotected sexual intercourse. This study was conducted to update the description of HIV subtypes circulating in Slovakia. HIV-1 partial pol gene sequences from 143 individuals were prospectively collected from 2004 to 2008 and analyzed. Phylogenetic analysis based on HIV-1 partial pol gene sequences revealed the highest prevalence of HIV-1 B subtype (93.0 %), predominantly associated with the MSM group. Ten (7.0%) individuals were infected with HIV-1 non-B subtypes. The pure subtypes were more frequent (7; 4.9%) than CRFs (3; 2.1%) and their occurrence was as follows: subtype C (3; 2, 1%), subtype A (2; 1.4%), subtype F (2; 1.4%), CRF_01AE (1; 0.7%), CRF_02AG (1; 0.7%), and CRF08_BC (1; 0.7%). Data show slightly increasing HIV-1 subtype diversity, with HIV-1 subtype B still having the highest prevalence in the Slovak-infected population.

Prevalence of a 32 bp deletion in the gene for human immunodeficiency virus 1 co-receptor CCR5 in Slovak population.

The chemokine (C-C motif) receptor 5 (CCR5) represents a major co-receptor for macrophagetropic Human immunodeficiency virus 1 (HIV-1) strains. A 32 bp deletion mutant allele in the CCR5 gene (CCR5-Δ32) provides to homozygotes a strong resistance to HIV-1 infection. In this study, the prevalence of CCR5-Δ32 in 200 HIV-1-negative and 162 HIV-1-positive individuals was determined. The presence of CCR5-Δ32 in blood samples was detected by PCR. CCR5-Δ32 was found to be homozygous in 1% and heterozygous in 17% of the HIV-1-negative individuals. In HIV-1-positive patients, no homozygous CCR5-Δ32 was found, while heterozygous CCR5-Δ32 occurred in 15.4% patients. Thus, no significant difference between HIV-1- negative and HIV-1-positive individuals was found, what is in accord with the findings obtained in other EU countries. The results of this study do not indicate that a relatively low incidence of HIV-1 infection in Slovakia could be caused by the CCR5-Δ32 mutation.

Alternative splicing variant of the hypoxia marker carbonic anhydrase IX expressed independently of hypoxia and tumour phenotype.

CA IX is a hypoxia-induced, cancer-associated carbonic anhydrase isoform with functional involvement in pH control and cell adhesion. Here we describe an alternative splicing variant of the CA9 mRNA, which does not contain exons 8-9 and is expressed in tumour cells independently of hypoxia. It is also detectable in normal tissues in the absence of the full-length transcript and can therefore produce false-positive data in prognostic studies based on the detection of the hypoxia- and cancer-related CA9 expression. The splicing variant encodes a truncated CA IX protein lacking the C-terminal part of the catalytic domain. It shows diminished catalytic activity and is intracellular or secreted. When overexpressed, it reduces the capacity of the full-length CA IX protein to acidify extracellular pH of hypoxic cells and to bind carbonic anhydrase inhibitor. HeLa cells transfected with the splicing variant cDNA generate spheroids that do not form compact cores, suggesting that they fail to adapt to hypoxic stress. Our data indicate that the splicing variant can functionally interfere with the full-length CA IX. This might be relevant particularly under conditions of mild hypoxia, when the cells do not suffer from severe acidosis and do not need excessive pH control.

Meningococcal meningitis is still the commonest neuroinfection in the community in tropics: overview of 62 cases.

Within last 17 years we went through all charts of bacterial meningitis within our nationwide survey and among 372 cases we found 62 cases of MM, in 12 cases with meningococcal disease (with shock, petechial effusions or disseminated intravascular coagulation or digital gangrenes). MM was usually observed in young adults without any of investigated risk factors like neoplasia, ENT (ear, nose, throat) focuses, elderly age, sepsis, diabetes, alcoholism, trauma, neonatal VLBW etc. Trauma, diabetes mellitus, alcohol abuse and chronic sinusitis/otitis were significantly less frequently found as a risk factor for MM. Mortality was very low, only 4.8% and was lower than overall mortality in CBM (12.4%, NS). Also the proportion of neurologic sequellae (9.7%) and initial treatment failure (8.1%) were comparable or even lower. This positive outcome results are probably because all N. meningitis strains were susceptible to penicillin, chloramphenicol, cefotaxim, cotrimoxazol or ciprofloxacin. Other reason for low mortality was that most cases received oral antibiotic immediately, even before admission (50 of 62). 95.2% of cases survived, 90.3% without any transient neurological residual symptoms.

Meningitis in diabetic patients.

Community acquired bacterial (CBM) meningitis in diabetic patients was analyzed for risk factors and outcome in a cohort of 201 cases of meningitis within last 17 years: 15 patients with diabetes mellitus and meningitis were identified and compared for etiology and mortality as well as for neurologic sequellae with all CBM cases.

Ten years experience with 497 cases of neuroinfections in tropic: in limited laboratory infrastructure initially treat both, cerebral malaria and meningitis.

Review of 497 cases of neuroinfections in 7 tropical clinics in Ethiopia, Uganda, Burundi, Kenya, Sudan within 2000-2007 was performed. 97.5% of all cases was cerebral malaria (40.1%) and bacterial meningitis (56.4%). TB meningitis, cerebral cryptococcosis and sleeping sickness were very rare.

Genetic diversity of Enterococcus faecium isolated from Bryndza cheese.

One hundred and seventy-six Enterococcus faecium isolates from Slovak dairy product Bryndza were tested for the presence of plasmid DNA. Eighty-two isolates were positive and their plasmid DNA was isolated and digested by EcoRI and HindIII restriction endonucleases. The patterns obtained were compared with those obtained after pulsed-field gel electrophoresis of macrorestriction fragments (PFGE), (GTG)(5)-PCR and ERIC-PCR. All these molecular approaches were applied for the study of genetic variability and determination of strain relatednesses among plasmid-positive isolates of E. faecium. In general, all methods revealed a considerable genetic diversity of E. faecium isolates. Plasmid profiling and ERIC-PCR have offered a higher resolution than PFGE and (GTG)(5)-PCR.

Xyloglucan endotransglycosylase: evidence for the existence of a relatively stable glycosyl-enzyme intermediate.

Xyloglucan endotransglycosylases (XETs) catalyse the breakdown of xyloglucan molecules predominantly by transglycosylation. In this process, fragments of cleaved polysaccharide are preferentially transferred to other xyloglucan molecules or their oligosaccharide subunits, with overall retention of the anomeric configuration of the glycosidic bond. In accordance with the theory, we propose that the cleavage and re-formation of the glycosidic bond in xyloglucan involves the formation of a glycosyl-enzyme intermediate which decomposes by transfer of the glycosyl moiety to a suitable carbohydrate acceptor. XETs from nasturtium seed cotyledons, mung bean hypocotyls and cauliflower florets interacted with xyloglucan to form complexes of high Mr as judged by gel-permeation chromatography. The nasturtium enzyme also showed evidence of XET-xyloglucan complex-formation according to anion-exchange chromatography and adsorption of the complex to filter paper on the basis of affinity of its xyloglucan moiety for cellulose. The XET-xyloglucan complex was stable in water, 6 M urea and acidic and alkaline buffers (pH 2.5-9.5), but readily decomposed by transferring its glycosyl moiety to xyloglucan-derived oligosaccharides or by incubation with the strong nucleophile imidazole at pH 3.8-9.6. These results strongly support the assumption that XET forms a relatively stable covalently linked glycosyl-enzyme intermediate.