Extracellular vesicles in infectious diseases - importance and perspectives.

Extracellular vesicles (EVs) are mother cell derived transport units released into the extracellular environment. They are a new pillar of intercellular communication as they carry nucleic acids, proteins, and other signalling molecules, protecting them from degradation in the extracellular environment until fusion of the vesicle with the target cell. The transport mechanism relies on surface structures involved in cell adhesion. It is well known that all cellular organisms are capable of producing EVs. Most human cells have this capability, and EVs can be detected in all body compartments. At the time of their discovery, EVs were considered as useless waste vesicles of marginal interest. Thanks to the newly described transport mechanisms of biologically active molecules, EVs are currently known to participate in a variety of homeostatic mechanisms. In infectious diseases, the most studied area is the modulation of the immune response, where they are seen as potential biomarkers, as their production or the content they carry can be altered under pathological conditions. For microbes, interactions at the pathogen-pathogen and pathogen-host level are at the forefront of attention. EVs also have potential for use as drug delivery systems and novel targets for pharmacotherapy.

Increasing procoagulant activity of circulating microparticles in patients living with HIV.

OBJECTIVES: HIV-infected individuals are at higher risk of non-AIDS diseases associated with procoagulant status. Microparticles are elevated in disorders associated with thrombosis (e.g., cardiovascular diseases). We investigated the association between microparticle levels in untreated and treated HIV-infected subjects, and determined the association with immune status, viral replication, and duration of antiretroviral therapy. PATIENTS AND METHODS: We included 144 HIV-infected subjects, including 123 on antiretroviral therapy (ART) and 21 before treatment initiation. A control group of 40 HIV-negative healthy adults matched for age and sex was used for comparison of microparticle levels. Treated subjects were divided into five groups depending on the period of antiretroviral exposure. Statistically significant differences were determined by Kruskal-Wallis test and Chi2 test. The relation between microparticles and other parameters was assessed using Spearman's coefficient of correlation. RESULTS: Microparticle levels were significantly higher in treated and untreated HIV-infected subjects than in non-HIV-infected controls (P<0.001). The microparticle level was similar between the groups on treatment (P=0.913). No association between the microparticle level and CD4+ count, CD4+/CD8+ ratio, number of HIV-1 RNA copies, or duration of exposure to antiretroviral treatment was observed. CONCLUSION: Increased levels of microparticles may be due to processes independent of viral replication and CD4+ cell count, and microparticle release might persist even during viral suppression by antiretroviral treatment. Elevated microparticle levels might occur in response to other triggers.

Progressive multifocal leukoencephalopathy - epidemiology, immune response, clinical differences, treatment.

Progressive multifocal leukoencephalopathy (PML) is a severe disease of the central nervous system with very high mortality. It is caused by the JC virus with high seroprevalence, at up to 80%. Development of PML is typically opportunistic, particularly in acquired immunodeficiency syndrome, and usually affects patients with profound immunodeficiency. Furthermore, as a result of highly efficient immunosuppressive and immunomodulatory treatments in recent years, the number of PML cases has increased in the general population. In this article, the authors mention virological and epidemiological relationships and characteristic manifestations of PML. Possible relationships of humoral and cellular immunity are discussed and limited treatment options including prophylaxis are mentioned.

[Guidelines for caring for HIV-infected adults and postexposure prophylaxis for HIV infection]. / Doporuceny postup pece o dospele infikovane HIV a postexpozicni profylaxe infekce HIV.

The authors present instructions for providing antiretroviral therapy in the Czech health care system, based partly on recommendations from abroad and partly on their own experiences of caring for HIV /AIDS patients. The structure and content are similar to those in the 2010 edition, with new study outcomes and modern trends in treatment strategy being taken into consideration. The guidelines are based on systematic patient assessment and aimed at making an accurate diagnosis and formulating recommendations according to individual criteria. The document provides specific instructions for decisions on initiating antiretroviral therapy, selection of individual drugs, monitoring of treatment effect and adverse reactions, and reaction to potential therapy failure. Special attention is paid to administration of antiretroviral drugs to pregnant women and patients with comorbidities, especially tuberculosis, hepatitis or renal insufficiency. The new version includes procedures for postexposure prophylaxis for HIV infection. The guidelines are supplemented by a table summary of antiretroviral drugs. The presented document is to be used in negotiations between the association,state authorities and health care payers.

[Simplification - higher effectiveness of antiretroviral therapy]. / Simplifikace- vyssí efektivita antiretrovirové lécby.

An essential precondition for antiretroviral treatment is the deep viral suppression that may be attained only by the long-term and full adherence of the patient. Non-adherence and irregular drug use increase the risk of the selection of resistant HIV mutants and the unfavorable clinical consequences of continuous virus replication. The risks of virologic failure, disease progression and death increase. The full treatment potential of antiretroviral therapy is associated not only with the effectiveness and safety of the specified drugs, but also with the complexity or simplicity of the relevant treatment regimens. The results of more retrospective analyses showed that a simpler regimen leads to better adherence than more complex regimens. Recently, antiviral treatment regimens have been consistently simplified. The highest level of simplification consists of a co-formulation of drugs for the whole daily dose called a single-tablet regimen. Currently, there are three preparations for such regimens in clinical practice - EFV/TDF/FTC, RPV/TDF/FTC and EVG/COBI/TDF/FTC. In patients using these therapeutic regimens, a positive economic impact may be seen in addition to the primary aspect, i.e. less frequent hospitalizations and lower health care costs.

[Polymicrobial brain abscess in hereditary haemorrhagic telangiectasia (Osler's disease)]. / Polymikrobieller Hirnabszess bei hereditärer hämorrhagischer Teleangiektasie (Morbus Osler).

HISTORY AND ADMISSION FINDINGS: A 38-year-old woman who suffered from migraine was admitted because of severe, worsening headache for 24 hours (dissimilar to the previous migraine attacks), with impaired vision and weakness of the right arm. Mild hemiparesis and expressive aphasia indicated an intracranial tumor. INVESTIGATIONS: Cranial computed tomography revealed a focal lesion with a diameter of 2.5 cm in the left frontoparietal lobe, with signs of intracranial hypertension, indicating cerebral metastasis or an abscess. Magnetic resonance imaging confirmed the diagnosis of a brain abscess. TREATMENT AND COURSE: An urgent craniotomy was performed and the abscess was evacuated. An empirical antibiotic combination with chloramphenicole and metronidazole (switched to cefotaxime because of thrombocytopenia) was initiated. Cultivation of pus revealed Streptococcus constellatus, Aggregatibacter aphrophilus and Fusobacterium spp. Within the first two weeks of treatment progession of the abscess was noted, therefore a second craniotomy with debridement was performed. An elective CT-angio scan revealed several arteriovenous malformations in the caudal segments of both lungs which were embolized without complications. Only retrospectively, cutaneous teleangiectasias were recognized. At present, the patient and her direct relatives are submitted to genetical screening for Osler's disease. CONCLUSION: In patients with brain abscesses of unknown origin and with a history of repeated epistaxis and/or gastrointestinal bleeding, Osler's disease (hereditary hemorrhagic telangiectasia) should be considered and pulmonary arteriovenous malformations excluded. Physicians should search for cutaneous or mucous teleangiectasias. Family screening and long-term follow-up according to international guidelines is recommended.

Ascorbic acid: an old player with a broad impact on body physiology including oxidative stress suppression and immunomodulation: a review.

Ascorbic acid is a low molecular weight antioxidant well known as anti-scorbut acting vitamin C in humans, primates and guinea pigs. This review summarizes basic data about ascorbic acid in its physiological action point of view. It is divided into biochemistry of ascorbic acid synthesis, mechanism of antioxidant action and participation in anabolism, pharmacokinetics and excretion, exogenous ascorbic acid immunomodulatory effect and participation in infectious diseases, impact on irradiation and intoxication pathogenesis, and supplementary demands. The primary intention was to consider ascorbic acid not only as an antioxidant but also as a chemical compound affecting multiple pathways with a potential beneficial impact in many diseases and processes in human body.

[Blood lipid changes at long-term antiretroviral treatment]. / Zmeny krevních lipidu pri dlouhodobé antiretrovirové lécbe.

UNLABELLED: The aim of study was to find the development trend of blood lipid concentration in a group of HIV positive patients treated by combination antiretroviral therapy (cART). We followed changes during the therapy and evaluated their aterogennic nature. METHODS: The group included 118 patients stepwise allocated to the AIDS Centre of the Faculty Hospital Brno, with the monitoring period being up to 1 month as the minimum and up to 17 years as the maximum. The patients were divided into cART treated patients and not treated patients. The following parameters were analysed: total cholesterol, triglycerides, HDL-cholesterol, apolipoprotein B, the total cholesterol/HDL-cholesterol index and non-HDL-cholesterol. RESULTS: Our group experienced a statistically significant increase of total cholesterol concentration already in the first months after cART initiation and this value continuously increased in the following years. The recommended target value for total cholesterol (5 mmol/l) was exceeded in the group of patients after 3-4 years of cART initiation. The triglyceride concentration showed a sudden increase already a few months after cART initiation, when the recommended optimum value of triglycerides (1.7 mmol/I) was exceeded. These changes had a further no statistic significance. The average triglyceride value was all around (slightly above) 1.7 mmol/l. Our group experienced a statistically significant increase of HDL-cholesterol concentration in the first two years after cART initiation. A statistically significant change of HDL-cholesterol concentration was not found in the following years. The average HDL-cholesterol value was above optimal value HDL-Ch > 1.0 mmol/l for men (except initial category). A statistically significant change of apolipoprotein B concentration was found after 3-4 years of cART treatment. However, the average apolipoprotein B value did not exceed the target value in any of the followed categories. No statistically significant changes of the total cholesterol/HDL-cholesterol index were found. The resulting value was under 5 in all the followed categories. Statistically significant changes of non-HDL-cholesterol were found in patients with cART already a few months after treatment initiation and its concentration continually increased. However, the recommended target value of non-HDL-cholesterol (3.8 mmol/l) was exceeded only in the category of patients treated 4 - 5 years. The development trend of CD4+ lymphocyte count and HIV-1 RNA copies means high active of cART from standpoind of immunoregeneration (CD4+ lymphocyte count) and viral suppression (HIV-1 RNA copies) even in the group of treated patient with the longest monitoring period. CONCLUSION: Monitoring of our group of HIV-positive patients treated by combination antiretroviral therapy revealed a statistically significant increase of blood lipid concentrations (inclusive of HDL-cholesterol) during the treatment. However, these changes do not have an unequivocally aterogennic nature even in the group of treated patient with the longest monitoring period.

Macrophage-assisted inflammation and pharmacological regulation of the cholinergic anti-inflammatory pathway.

Macrophages play an important role in the immune system. They also participate in multiple processes including angiogenesis and triggering of inflammation. The present study summarizes pieces of knowledge on the importance of macrophages in disease, especially the inflammation. Special attention is paid to the cholinergic anti-inflammatory pathway (CAP) associated with the nicotinic acetylcholine receptor (nAChR) and the parasympathetic nervous system. The current pharmacological effectiveness in suppressing the inflammation in general and the septic shock in particular, is limited. CAP was discovered recently and it seems to be a suitable target for the development of new drugs. Moreover, available drugs binding to either nAChR or acetylcholinesterase (AChE) are candidates for either an inhibition or enhancement of CAP. Though the current scientific databases do not include all necessary data on the association of CAP with body functions and the research is quite intensive, the objective of the present review is to introduce the current trends and to critically evaluate CAP and macrophage-associated pathways.

[HIV lipodystrophy]. / HIV lipodystrofie.

Combined antiretroviral therapy results in extraordinary decrease of morbidity and mortality of HIV-infected patients and in an essential change of the HIV/AIDS disease prognosis. However, long-term intake of antiretroviral medicaments is related to occurrence of metabolic and morphological abnormalities, of which some have been combined into a new syndrome--the so called HIV lipodystrophy. The HIV lipodystrophy syndrome covers metabolic and morphological changes. Metabolic changes include dyslipidaemia with hypercholesterolaemia and/or hypertriglyceridaemia, insulin resistance with hyperinsulinaemia and hyperlaktataemia. Morphological changes have the nature of lipoatrophia (loss of subcutaneous fat--on the cheeks, on extremities, on buttocks and marked prominence of surface veins) or lipohypertrophia (growth of fat tissue--on the chest, in the dorsocervical area, lipomatosis of visceral tissues and organs, fat accumulation in the abdominal area). Several HIV lipodystrophy features are very similar to the metabolic syndrome of the general population. That is why this new syndrome represents a prospective risk of premature atherosclerosis and increase of the cardiovascular risk in young HIV positive individuals. The article mentions major presented studies dealing with the relation of antiretroviral treatment and the cardiovascular risk. The conclusions of the studies are not unequivocal--this is, among others, given by the reason that their length is short from the viewpoint of atherogenesis. The major risk of subclinical atherosclerosis acceleration seems to be related to the deep immunodeficiency and low number of CD4+ lymphocytes and florid, uncontrolled HIV infection with a high number of HIV-1 RNA copies actually circulating in the plasma. The question, whether metabolic and morphological changes related to HIV and cART carry a similar atherogenic potential as in the general population, remains open for future.

[Hypertension in HIV positive patients]. / Hypertenze u HIV pozitivních pacientu.

Survival of HIV-positive patients on highly active antiretroviral therapy (HAART) has significantly improved. Although traditional heart complications of the infection such as pericarditis or myocarditis has become rather rare owing to the therapy, wide range of metabolic abnormalities have been described. We focused on the evaluation of prevalence of hypertension among HIV positive patients with respect to their high cardiovascular risk. We examined 40 HIV positive patients (28 males and 12 females) followed in AIDS center in Brno. All probands underwent 24-hour ambulatory blood pressure monitoring as a part of their cardiological examination. 40 age- and gender-matched healthy controls were recruited. We evaluated the average value of systolic (SBP) and diastolic (DBP) blood pressure as well as the average value of heart rate (HR) within 24 hours of monitoring. Following values were found in the group of healthy controls: SBP 124.1 +/- 8.6 mm Hg, DBP 71.6 +/- 6.9 mm Hg and HR 67.9 +/- 9.7/min. HIV positive patients presented with the following values: SBP 118.5 +/- 9.3 mm Hg, DBP 76.8 +/- 5.7 mm Hg a HR 78.6 +/- 9.7/min. All the differences were statistically significant at p < 0.05. We diagnosed 14 patients with hypertension defined as SBP higher than 125 mm Hg and/or DBP higher than 80 mm Hg in both of the groups. Prevalence of hypertension in HIV positive patients was comparable to that seen in healthy controls. HIV positive patients had lower SBP but higher DBP and HR.

[Dyslipidaemia inducted by antiretroviral agents]. / Dyslipidemie indukovaná antiretrovirovými lécivy.

The clinical course of HIV/AIDS has been substantially modified by up-to date therapy in the recent years. The progress of the disorder has changed--today it is a chronic disease of many years course. Already in 1997 and 1998 it turned out that adverse metabolic changes which significantly affect the subsequent progress of the disease were produced by long-term HAART (highly active antiretroviral therapy). Gradually, more and more anthropometric, metabolic and coagulation changes are detected, closely resembling the changes seen in the metabolic syndrome, well known from cardiology and internal medicine--dyslipoproteinaemia, insulin resistance, abdominal obesity and so on. A combination of these disorders is clinically significant due to their role in the development of atherosclerosis and their, by no means negligible, involvement in the onset of ischaemic heart disease. In view of the much lower average age of HIV-positive individuals the earlier mentioned complications should be expected in much lower age categories than with HIV-negative individuals. Plasma lipid fractions (total cholesterol, triglycerides, LDL-cholesterol, HDL-cholesterol, apoA-I, apoB, LDL/HDL, apoA-I/apoB) have been investigated in 69 HIV infected subjects and the changes of these parameteres in the course of progression of HIV/AIDS due to cumulative time of exposure to HAART were explored. Significant increase of the level of proatherogenic plasma lipid fractions with tendency to develop at time course was found. These disturbances are observed in the course of very good immunological stabilization and viral suppression. No unambiguous data and results of long term studies are available, that would confirm the increase of cardiovascular risk in HIV infected subjects. Nevertheless, this increase is required and anticipated.

[HIV/AIDS and pathology in blood count]. / HIV/AIDS a patologie v krevním obrazu.

BACKGROUND: HIV/AIDS pandemy has hit the entire world. With the use of retroviral therapy the disease became chronic. The life prolongation often leads to complications in various organs. The aim of our work was to determine the frequency of blood count pathology at the time when the HIV infection was diagnosed, that means before any antiretroviral treatment was administered, and its relation to the disease stage. METHOD AND RESULTS: Out of 70 patients registered in AIDS centre in Brno University Hospital by 1st March 2006, we have complete blood count results including absolute number of CD4+ lymphocytes. Out of these 70 we evaluated a group of 64 HIV-positive individuals (17 women, 47 men), who were examined at the time the disease was diagnosed. Average and medians of all blood count parameters were within the reference range, only CD4+ lymphocytes in 1 mm(3) were out of range. Pathology in red blood cells count was found 26 times (41.9 % of examined patients), in white cell count 22 times (35.5 %). Thrombocyte number was affected 3 times, and only in one of these cases it was a separate finding. CONCLUSIONS: Blood count pathology is relative frequent in the HIV infected. Therefore HIV infection should be considered as one of the possible causes of unexplained blood count pathology.

[Initial experience with treatment of chronic hepatitis C in HIV-positive patients]. / První zkusenosti s lécbou chronické hepatitidy C u HIV-pozitivního nemocného.

A 30 years old man originating from Ukraine was infected by the human immunodeficiency virus (HIV) and virus of hepatitis C (HCV) due to injection administration of drugs of abuse in his own country before coming to Czech Republic. He was infected by genotype 3 of HCV and the infection became chronic. Under the influence of a three-combination anti-retrovirus therapy his conditions related to HIV infection became stable and it proved to be possible to apply a combined treatment by alpha-interferon and ribavirin at commonly used doses for the period of 12 months. In the course of therapy the HCV nucleic acid (HCV RNA) disappeared from serum and serum activity of alanine aminotransferase (ALT) became normal. However, two months after the therapy ended a relapse of the disease occurred--HCV RNA reappeared in serum and ALT activity increased. The therapy was well tolerated. A rapid decrease of hemoglobin level during the first four weeks of therapy was stopped by reduction of ribavirin dose.

The polyvalent staphylococcal phage phi 812: its host-range mutants and related phages.

Ninety-five percent of 782 culture collection strains, as well as hospital strains of Staphylococcus aureus subsp. aureus of different provenance and 43% of 89 culture collection strains of different coagulase-negative species of the genus Staphylococcus, were found to be sensitive to the polyvalent phage phi 812 or to at least one of its host-range mutants or to the polyvalent phages SK311, phi 131, and U16. Thus sensitivity to the polyvalent staphylococcal phages seems to be one of the common features of S. aureus subsp. aureus strains. The adsorption kinetics and one-step growth characteristics of the phages phi 812 and SK311 were estimated. Restriction genomic maps of the phages phi 812 (146.5 kb) and SK311 (141.1 kb) were constructed by use of the restriction endonucleases AvaII, PstI, KpnI, SacI, SmaI, and XhoI. The host-range mutations of the phage phi 812 were localized on this map. Comparison of restriction patterns of the phages phi 812 and SK311 with those of the polyvalent phages U16 and phi 131 suggests that all these phages are closely related. Their genomes differ from each other mostly by some deletions, insertions (1-3 kb), or inversions. Evidence was given that the phage phi 812 together with SK311, phi 131, and U16 belongs in the phage species Twort, the description of which is substantially supplemented with the data on the phage phi 812 reported in this paper.

Pulsed-field gel electrophoresis of the genomic restriction fragments of coagulase-negative staphylococci.

The genomes of 47 coagulase-negative staphylococcal strains assigned to different species were analysed by pulsed-field electrophoresis. The strains were clustered on the basis of their similarity in the SmaI restriction patterns into various groups, each group consisting of the type strain and the strains whose SmaI restriction patterns were similar to that of the type of strain. The SmaI restriction groups seem to correspond to the following species: Staphylococcus warneri, S. hominis, S. xylosus, S. lugdunensis, S. kloosii, S. haemolyticus, S. lentus, S. cohnii, S. equorum, S. chromogenes, S. saprophyticus, S. simulans, S. carnosus, S. capitis and S. auricularis. The species S. sciuri, S. caseolyticus, S. gallinarum, S. epidermidis and S. schleiferi were represented only by their type strains and showed no similarity in their SmaI restriction patterns neither to each other nor to all the other species investigated here. Thus, the classification of coagulase-negative staphylococcal strains into the above species seems to be confirmed also by genome restriction analysis carried out by pulsed-field gel electrophoresis.