Ultrasound detection of non-atherosclerotic intima-medial abnormalities of lower limbs arteries in amateur endurance runners.

BACKGROUND: Structural changes in the lower limb's arterial wall in amateur endurance runners are a rare incidental finding, represented just by several case reports. AIM: Study the incidence of non-atherosclerotic lower limb artery wall changes in defined group of amateur endurance runners and identify relationship with the training parameters and the relevant biochemical markers. METHODS: Amateur male athletes engaged in endurance running for more than 5 years were enrolled. Tibial and anterior popliteal arteries on each side were examined by ultrasound with focus on non-atherosclerotic structural wall changes: intima-medial border blurring, presence and character of non-atherosclerotic noduli. Subsequently the descriptive and correlation analysis were performed. RESULTS: The study enrolled 20 amateur male endurance runners from Black Swan Triathlon Club Slovakia. The low atherosclerotic risk was represented by normal lipid levels, BMI under 30 kg/m2 and non-smokers in all participants. At least one type of structural artery wall abnormality (noduli or intima-medial border blurring) was present in 19 of 20 participants (95%). The most present was the intima-medial blurring. (80% of participants). The noduli were present in 65% of study group, in almost 40% of these, they were considered as hyperechogenic. All these affections were predominantly in popliteal artery area (65%). The vast majority has bilateral affection. We find a mild correlation between these ultrasound findings and training load represented by annual kilometers and run hours. There was no association between these changes and lipid spectrum or CRP level. CONCLUSION: The subclinical lower limb artery changes, represented by intima-medial border blurring and non-atherosclerotic noduli were present in almost every amateur endurance runner. Despite the underlying mechanism is not understood, the increased training load seems to be one of the responsible factors.

Cell-to-cell transport in viral families: faster than usual.

The most frequent way of virus dissemination is through the canonical receptor-mediated pathway. However, when unfavorable conditions, such as presence of antibodies appear, the viruses use more peculiar routes of transmission to protect themselves. Here we describe most of the routes, from syncytia formation, tunneling nanotubes and filopodia, through immunological and virological synapses to actin comets formation. We describe the cell-to-cell transport in different viral families to show that this way of virus distribution is present in almost all the mammalian virus families and is not as uncommon as it was thought. The knowledge of the ways of viral transport might lead us to exploit more successful therapeutic approaches and fight the most threatening diseases. Keywords: cell-to-cell transmission; tunneling nanotubes; viral synapses; filopodia; actin comets.

Absence of keratin 1 restricts the course of infection with lymphocytic choriomeningitis virus strain MX.

A rodent-transmitted enveloped lymphocytic choriomeningitis virus (LCMV) is an RNA virus causing persistent infection. During persistent infection, a unique strain MX of LCMV does not yield infectious virions, therefore it is not able to use a receptor for its dissemination, and spreads by cell-to-cell contacts. Virus can be transported to the neighboring cell by different cellular structures such as tunneling nanotubes or cytonemes. Using q-PCR, immunofluorescence, siRNA and western blot, we show that keratin 1 (K1) is essential for the persistent infection caused by LCMV strain MX, and its absence very effectively slows down the course of infection. In contrast, other LCMV strains, namely Clone 13 and Armstrong, which produce expression of K1, desmosomes in cells expressing K1 (42-MG-BA) but not in cells without K1 expression (NIH/3T3). We conclude that the presence of the virus enhances the K1 expression, while the presence of K1 protein potentiates the viral spread in persistently infected cells. Keywords: lymphocytic choriomeningitis virus; keratin 1; persistent infection; desmosomes; virus transport.

Cell-to-cell transmission of lymphocytic choriomeningitis virus MX strain during persistent infection and its influence on cell migration.

Lymphocytic choriomeningitis virus (LCMV) can establish in its host a persistent infection, without any prominent symptoms. Even during this infection, when the infectious virions are not released, the virus still disseminates effectively. A very effective and fast way of infection of neighboring cells utilized by many viruses is cell-to-cell transmission. Viruses use different ways of cell-to-cell spread through the extracellular space or by intracellular means through different protrusions. We have found that LCMV strain MX may use three different types of cell-to-cell transport. Firstly, similar to vaccinia virus, it can use actin to propel the virus towards the neighboring cell. Secondly, virus can travel through the intracellular space inside the tunneling nanotubes, that connect the cells even at longer distances and thirdly, the virus may travel on the surface of the membrane of different protrusions connecting two cells. We have also proved that the cells infected by MX strain of LCMV migrate faster than the uninfected cells or cells infected with a different LCMV strain. In accordance with faster migration, the infected cells form more lamellipodia with high expression of keratin 1. In this work, we have introduced three types of cell-to-cell transmission utilized by strain MX of LCMV and showed that even if the cells are not in tight connection, the virus forces them to migrate faster to join the nearest cell. As we show in this work, the virus may use more than one strategy to move to another cell, while each strategy can substitute another. These ways of transmission are very fast and effective and may have a serious impact on the host. Moreover, targeting the cell-to-cell spread, by inhibiting for instance GTPase dynamin, could be an effective way of virus elimination. Keywords: lymphocytic choriomeningitis virus; transmission; migration; keratin 1; nucleoprotein.

Lymphocytic choriomeningitis virus: ways to establish and maintain non-cytolytic persistent infection.

Lymphocytic choriomeningitis virus (LCMV) is a prototype virus of the Arenaviridae family that is attracting considerable attention both as an important experimental model system to study acute and persistent viral infections, and as a neglected human pathogen of clinical significance. Notably, LCMV is capable of persisting in an infected host, and escaping the immune system. Here we describe the strategies used by the virus to establish and maintain long-term infection in vitro and/or persistent infection in vivo. We discuss how the viral components (RNA, nucleoprotein, glycoprotein, Z protein) manipulate the host cell machinery to facilitate survival and spread of the virus without disturbing the basal cellular processes. Deep understanding of these strategies is inevitable for the development of approaches towards restricting the virus spread and/or preventing its harmful reactivation. This review summarizes the current status in this area and presents ideas emerging from existing data.

Subcellular localization of proflavine derivative and induction of oxidative stress--in vitro studies.

Acridines have been studied for several decades because of their numerous biological effects, especially anticancer activity. Recently, cytotoxicity of novel acridine derivatives, 3,6-bis((1-alkyl-5-oxo-imidazolidin-2-yliden)imino)acridine hydrochlorides (AcrDIMs), was confirmed for leukemic cell lines [Bioorg. Med. Chem.2011, 19, 1790]. The mechanism of action of the most cytotoxic hexyl-AcrDIM was studied in this paper focusing attention on a subcellular distribution of the drug. Accumulation of hexyl-AcrDIM in mitochondria was confirmed after labeling mitochondria with MitoRED using ImageStream Imaging Flow Cytometer. The derivative significantly decreased intracellular ATP level (reduction of ATP level was decreased by vitamin E), and induced oxidative stress (ROS production detected by DHE assay) as well as cell cycle arrest in the S-phase (flow cytometry analysis) already after short-time incubation and induction of apoptosis. Cytotoxicity of hexyl-AcrDIM is closely connected with induction of oxidative stress in cells.

Lymphocytic choriomeningitis virus mx strain does not induce the expression of tumor-associated carbonic anhydrase IX in persistently infected HeLa cells.

Summary. - Lymphocytic choriomeningitis virus (LCMV) is an arenavirus that readily causes persistent infections, in which it does not interfere with vital functions of the cells, but can affect expression of "luxurious" genes. MX strain of LCMV (MX LCMV) has been identified as an agent transmissible by cell-to-cell contact in the human carcinoma MaTu cells grown in a mixed culture with HeLa cells. When compared to uninfected HeLa, the MaTu-MX-infected HeLa cells, to which the virus was transmitted via co-cultivation with mitomycin C-treated MaTu cells, showed an elevated expression of a protein called MN, suggesting that MN can be induced by MX LCMV. MN protein was later identified as the carbonic anhydrase isoform IX (CA IX), whose expression has been predominantly associated with hypoxic tumors of poor prognosis. Since the proposal that MX LCMV can induce such a cancer-related protein could substantially change our view on the biology of LCMV-host interaction we undertook its verification. Instead of co-cultivation, we used MaTu cell-free extracts to transmit MX LCMV to HeLa cells. These cells were then grown for more than 30 passages, but the level of MN/CA IX did not increase throughout the whole cultivation period as compared to uninfected HeLa cells. Moreover, a treatment of MaTu-MX-infected HeLa cells with ribavirin eliminated the virus, but did not reduce the MN/CA IX expression. Our results clearly showed that MN/CA IX is independent of MX LCMV and that the virus itself does not influence the MN/CA IX level in HeLa cells.