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Biomedical subjects

M Lichtner

Publications and source records attributed to M Lichtner.

At least 19 recordsLinked to original sources
PubMed2006

HIV protease inhibitor therapy reverses neutrophil apoptosis in AIDS patients by direct calpain inhibition.

The reduction of neutrophils apoptosis is one of the main non-virological effects of protease inhibitor (PI) therapy. We explore here whether this may be due to the cross-inhibition of calpain, an important non-virological target of PI in vitro. We found that the high basal level of neutrophils apoptosis in AIDS patients is strictly related to an increased intracellular calpain activity. Both alterations disappear after PI treatment, with apoptosis and calpain going back to normal levels after 3 months of PI therapy, independently of a proficient antiviral effect. PI drugs exerted a similar antiapoptotic and anticalpain effects on neutrophils in ex vivo experiments: strikingly, the effects were mimicked by commercially available calpain inhibitors. This study shows, for the first time, that apoptosis of neutrophils in AIDS patients is mediated by calpain, and that neutrophil survival in PI treated AIDS patients is a non virological effect due to calpain inhibition.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Circulating dendritic cells and interferon-alpha production in patients with tuberculosis: correlation with clinical outcome and treatment response.

Dendritic cells (DC) have been characterized recently as having an important role in the initiation and control of immunological response to Mycobacterium tuberculosis infection. Blood DC have been subdivided into myeloid (mDC) and plasmacytoid (pDC) subsets, on the basis of differences in phenotype markers and function. Little is known about the enumeration and functional evaluation of circulating DC in patients with tuberculosis and their correlation with clinical outcome during the course of anti-tuberculous treatment. We assessed circulating mDC and pDC counts measured by a newly developed single-platform flow cytometric assay based on TruCOUNT, as well as the production of interferon (IFN)-alpha after in vitro stimulation by herpes simplex virus (HSV-1) in 24 patients with active tuberculosis (TB) and 37 healthy donors. Absolute numbers of both DC subsets were decreased significantly in patients with active TB compared to controls. Similarly, the production of IFN-alpha was highly impaired. In 13 patients these parameters were assessed longitudinally, before and after the specific anti-microbial treatment. Most interestingly, in all nine patients with successful anti-tuberculous therapy there was a significant and marked increase of pDC counts and IFN-alpha production. In contrast, no significant longitudinal variations in DC counts and IFN-alpha production were observed in four patients with lack of response to specific treatment. In conclusion, active TB is associated with a defect in blood DC numbers and IFN-alpha production that is restored after bacterial clearance and clinical improvement, as a result of effective anti-tuberculous treatment.

Adolescent↗
PubMed2003

Anti-HIV drugs decrease the expression of matrix metalloproteinases in astrocytes and microglia.

The introduction of potent antiretroviral drugs for the treatment of patients with human immunodeficiency virus (HIV) infection has dramatically reduced the prevalence of HIV-associated neurological disorders. Such diseases can be mediated by proteolytic enzymes, i.e. matrix metalloproteinases (MMPs) and, in particular gelatinases, released from glial cells. The aim of this study was to investigate whether the antiretroviral drugs commonly used for the treatment of HIV-infected patients modulate the activity of MMPs in astrocyte and microglial cultures. Primary cultures of rat astrocyte and microglia were treated with different doses of zidovudine (AZT) or indinavir (IDV) for 20 h and simultaneously activated by exposure to lipopolysaccharide (LPS). Culture supernatants collected from astrocytes and microglia after 24 h incubation were subjected to gelatin zymography and western blot analysis for the assessment of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) protein levels. Total RNA was extracted from glial cells and used for reverse transcriptase-polymerase chain reaction for the assessment of mRNA expression. Our results indicate that both astrocyte and microglial cells constitutively express MMP-2 mRNA and protein. LPS treatment increased MMP-2 mRNA and protein expression in astrocytes, but not in microglial cells. The treatment with both AZT and IDV dose-dependently inhibited the expression of MMP-2 in astrocytes, whereas it had no effect on microglial cells. The expression of MMP-9 in both astrocytes and microglia was induced by LPS treatment and was dose-dependently inhibited by AZT and IDV treatment in LPS-stimulated astrocytes and microglia. These results raise the possibility that AZT and IDV interfere directly with MMP production in glial cells and independently from their antiviral activity, thus suggesting the possible therapeutical use in neurological diseases associated with MMPs involvement.

Animals↗
PubMed2001

Self-reported symptoms and medication side effects influence adherence to highly active antiretroviral therapy in persons with HIV infection.

OBJECTIVES: To identify variables predictive of nonadherence to highly active antiretroviral therapy (HAART) and to assess whether self-reported symptoms or medication side effects are related to adherence. DESIGN: Cross-sectional multicenter study Adherence Italian Cohort Naive Antiretrovirals [AdICONA] within the Italian Cohort Naive Antiretrovirals (ICONA). METHODS: Participants receiving HAART completed a 16-item self-administered questionnaire to assess nonadherence in the last 3 days as well as the type and intensity of 24 common HIV- and HAART-related symptoms experienced during the last 4 weeks. RESULTS: From May 1999 to March 2000, 358 persons were enrolled: 22% reported nonadherence and were less likely to have HIV RNA <500 copies/ml (odds ratio = 0.51; 95% confidence interval: 0.31-0.85). Frequency of moderate/severe symptoms or medication side effects in nonadherent participants ranged from 3.6% to 30%. On univariate analysis, nausea, anxiety, confusion, vision problems, anorexia, insomnia, taste perversion, and abnormal fat distribution were significantly associated with nonadherence. Nonadherent persons had a higher mean overall symptom score (12.3 +/- 9.2 versus 8.1 +/- 6.6; p <.001) and mean medication side effect score (2.9 +/- 2.7 versus 1.9 +/- 1.9; p <.001) when compared with adherent participants. In the multivariate analysis, nausea ( p =.003); anxiety ( p =.006); younger age ( p =.007); unemployment ( p <.001); not recalling name, color, and timing of drugs ( p =.009); running out of pills between visits ( p =.002); and being too busy ( p =.03) were independently associated with nonadherence in the last 3 days. CONCLUSIONS: In addition to patient characteristics, medication-related variables, and reasons for nonadherence, patient-reported symptoms and medication side effects were significantly associated with adherence to HAART.

Adult↗
PubMed2000

Ex vivo and in vitro effect of human immunodeficiency virus protease inhibitors on neutrophil apoptosis.

Polymorphonuclear leukocytes (PMNL) from human immunodeficiency virus (HIV)-infected patients exhibit accelerated apoptosis and impaired functional activity. HIV protease inhibitor-based therapy produces improvements in both acquired and innate immune responses. Ex vivo and in vitro effects of HIV protease inhibitors on apoptosis and chemotaxis of PMNL were evaluated. After therapy, there was a rapid and significant decrease of PMNL apoptosis, which correlated with increased chemotactic function. These findings were found both in patients with immunological and virological response and in control subjects who showed an increase in CD4(+) T cell counts but no concomitant decline in HIV load. After in vitro treatment with ritonavir or indinavir, apoptosis of both HIV-infected and -uninfected PMNL markedly decreased and correlated with significant enhancement of chemotaxis. These results suggest that HIV protease inhibitors may improve the PMNL function by reducing the apoptosis rate and that this effect may, at least in part, be independent of their antiviral activity.

Adult↗
PubMed2000

Interleukin-15 enhances neutrophil functional activity in patients with human immunodeficiency virus infection.

Polymorphonuclear leukocyte (PMN) dysfunction has been reported in human immunodeficiency virus (HIV)-infected patients. Interleukin (IL)-15 is a recently discovered cytokine that potentiates antimicrobial functions of normal PMNs. We evaluated the in vitro effect of IL-15 on chemotaxis and fungicidal activity of PMNs from 9 patients with untreated advanced HIV infection, 8 patients with viral suppression after 52 to 130 weeks of highly active antiretroviral therapy (HAART), and 12 patients with treatment failure. We also studied oxidative burst and apoptosis of PMNs in 5 patients with untreated advanced HIV infection. Twelve healthy donors were included as controls. Chemotaxis and fungicidal activity of unprimed PMNs was significantly lower in patients with untreated HIV infection compared with controls. After incubation with IL-15, a significant increase in PMN chemotaxis and fungicidal activity was found; moreover, IL-15 induced a significant reduction in the number of apoptotic HIV(+) PMNs. IL-15 did not modulate oxidative burst of HIV(+) PMNs as measured by chemiluminescence production. The in vitro priming of PMNs with IL-15 determined a complete reversal of defective chemotaxis and killing in all HAART-treated patients with long-term HIV suppression. IL-15 significantly enhanced chemotaxis and fungicidal activity also in patients with HAART failure. In conclusion, IL-15 is an important cytokine in the activation of the functional properties of HIV(+) PMNs, by delaying apoptosis and enhancing chemotaxis and fungicidal activity. The potent stimulant effect of IL-15 on PMN function was observed in antiretroviral naive patients as well as in individuals who were receiving HAART, including those with treatment failure. (Blood. 2000;96:1979-1984)

Antifungal Agents↗
PubMed2000

Spontaneous and anti-Fas-induced apoptosis in lymphocytes from HIV-infected patients undergoing highly active anti-retroviral therapy.

OBJECTIVE: The aim of this study was to investigate susceptibility to spontaneous or anti-Fas-induced apoptosis in peripheral blood mononuclear cells (PBMC) from HIV-positive patients before and during highly active anti-retroviral therapy (HAART). DESIGN: A longitudinal study was performed on 12 evaluable patients on HAART. This cohort was analysed prior to and at week 2, 4, 8, 16 and 24 after beginning HAART. Variations in CD4 and CD8 cells, viral load, susceptibility to spontaneous or anti-Fas-induced apoptosis in the presence of IL-2, IL-4 or IL-12 were studied. Expression of Fas and Bcl-2 were also assessed. METHODS: Levels of HIV RNA were determined by a quantitative reverse transcription-PCR assay. Apoptosis was evaluated by staining isolated nuclei with propidium iodide followed by multiparameter flow cytometry analysis. RESULTS: Spontaneous apoptosis of PBMC was promptly inhibited after the start of treatment. Similarly, anti-Fas-induced apoptosis diminished greatly during treatment. Expression of Fas decreased significantly, while that of Bcl-2 remained statistically unchanged during the first 24 weeks of therapy. Levels of apoptosis correlated inversely to CD4 cell counts and directly to viral load in a highly significant way. Expression of Fas was directly correlated to apoptosis. Interleukin (IL)-2, but not IL-4 or IL-12, protected PBMC of HIV-positive individuals from spontaneous or anti-Fas-induced apoptosis before and during HAART. CONCLUSION: These results suggest that regulation of apoptosis and of Fas expression are involved in immunoreconstitution during HAART.

Adult↗
PubMed2000

Changes in circulating levels of soluble cell adhesion molecules following highly active antiretroviral treatment of HIV-1-infected patients.

Increased levels of soluble cell adhesion molecules (sCAM) have been reported in HIV-1 infection and may possibly contribute to altering the adhesion mechanisms of phagocytic cells. We evaluated the effect of highly active antiretroviral therapy (HAART) on plasma levels of sL-selectin, sE-selectin, intercellular cell adhesion molecule-1 (sICAM-1), sICAM-3, and vascular cell adhesion molecule-1 (sVCAM-1). Study participants included 22 HIV-1-infected patients with a CD4+ T-cell count/microl below 500 who were started on a HAART regimen and followed up for 9 months. After the initiation of therapy, plasma sL-selectin concentrations progressively decreased to normal ranges in the majority of our patients (P < 0.001), while no changes in sE-selectin were found. In all patients sICAM-1 remained relatively constant at significantly elevated concentrations during the 9 months of therapy. A significant reduction in plasma concentrations of both sICAM-3 and sVCAM-1 was found; however, the levels of these sCAM were not normalized by HAART and remained significantly elevated throughout the study (P < 0.001). The reduced release of sL-selectin could improve the ability of phagocitic cells to migrate in response to chemotactic stimuli after starting HAART. On the other hand, the persistent elevation of sICAM-1, sICAM-3, and sVCAM-1 could reflect continuous HIV-1-mediated immune activation, despite adequate control of plasma HIV-1 replication by therapy.

Adult↗
PubMed1999

Improvement in neutrophil and monocyte function during highly active antiretroviral treatment of HIV-1-infected patients.

OBJECTIVE: To investigate the effect of highly active antiretroviral treatment (HAART) on neutrophil and monocyte function in patients with moderately advanced HIV-1 infection. DESIGN: Eighteen HIV-1-infected patients with CD4 T cell counts below 350/microl, no concomitant active infection, and no previous use of protease inhibitors were treated with indinavir or ritonavir and two reverse-transcriptase inhibitors and were followed up for 9 months. Ten age- and sex-matched healthy subjects were included as controls. METHODS: The functional activity of neutrophils and monocytes was measured by assessing chemotaxis towards a bacterial peptide, killing activity against Candida albicans, and oxidative burst as measured by chemiluminescence production. RESULTS: Neutrophils and monocytes from the treatment group exhibited a significantly diminished baseline chemotactic and fungicidal activity compared with healthy controls (P < 0.001). After starting HAART, there was a significant improvement in chemotaxis and fungicidal activity of phagocytic cells (P < 0.001). Values of chemotaxis reached normal ranges in 13 out of 18 patients (72%) for neutrophils and eight out of 18 (44%) for monocytes, whereas phagocyte killing was rarely restored to normal values (3/18 cases for monocytes and 0/18 for neutrophils). The administration of HAART was also associated with significantly increased phagocyte chemiluminescence production in response to phorbol-12-myristate 13-acetate or opsonized C. albicans (P < 0.01). CONCLUSION: The functional improvement of two critical components of innate antimicrobial immunity, such as neutrophils and monocytes, may contribute to the improved cell-mediated immune responses against opportunistic infections in HAART-treated patients.

Adult↗
PubMed1999

Search for an antibody profile of Rhodococcus equi infection in AIDS patients despite the diversity of isolates and patient immune dysfunction.

Diversity of virulence-associated antigens of Rhodococcus equi was detected among thirteen strains isolated from AIDS patients on two continents. One out of four Brazilian isolates presented the virulence-associated antigen of 15- to 17-kDa, and the other three isolates had the 20-kDa virulence-associated antigen. In contrast, only three out of nine Italian isolates were positive for virulence-associated antigens - two for the 15- to 17-kDa antigen and one for the 20-kDa antigen. In four other Italian strains, one or more other low-molecular-weight antigens were identified. Because of R. equi variability and host immune dysfunction, no characteristic antibody profile was detected among patients, although the presence of specific antibodies in serum samples suggested prognostic value: good patient outcome and recovery from pneumonia were correlated with R. equi antibody detection, whereas the lack or disappearance of specific antibodies, mainly those to low-molecular-weight antigens, was correlated with disease progression and patient death. These results confirmed the nonobligatory presence of the well-known virulence-associated antigens for the pathogenicity of R. equi in humans, and also the diversity of R. equi strains isolated from AIDS patients, which may be related to the geographic origin of the isolates or may be a consequence of the route of R. equi transmission in different countries. Some mechanisms underlying the results obtained are discussed, suggesting immune complex formation during the progress of the disease.

AIDS-Related Opportunistic Infections↗
PubMed1999

Search for Virulence-Associated Antigens of Rhodococcus equi in Strains Isolated from Patients with Acquired Immunodeficiency Syndrome.

Rhodococcus equi (formerly Corynebacterium equi) are known to be highly virulent, intermediate in virulence, or avirulent correlated with specific virulence-associated antigens identified immunochemically by different molecular weights. The association of virulence antigens with infection of AIDS patients by this organism has not been sufficiently evaluated in Brazil or Italy. The objective of the present study was to search for virulence-associated antigens of 15-to 17-kD and 20-kD in Rhodococcus equi strains isolated from patients with rhodococcal infection and AIDS. Four Brazilian and 9 Italian strains were studied. All isolates were analyzed by gel electrophoresis followed by immunoblotting using specific monoclonal antibodies to identify virulence-associated antigens. The results obtained on gel electrophoresis analyses showed complexing of R. equi components with proteins of molecular weights ranging from 10-to 150-kD. By immunoblotting, a wide diversity in R. equi virulence-associated antigens was detected: 1 of the 4 Brazilian isolates and 2 Italian isolates had the 15-to 17-kD virulence-associated antigen, 3 Brazilian isolates and 1 Italian isolate had the 20-kD virulence-associated antigen, and the other Italian isolates had no virulence-associated antigens. These results indicate that the pathogenicity of R. equi strains for humans does not depend only on the presence of these well established virulence-associated antigens.

Journal Article↗
PubMed1998

Chemokine profiles in the cerebrospinal fluid (CSF) during the course of pyogenic and tuberculous meningitis.

The concentrations of the chemokines IL-8, monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-1alpha (MIP-1alpha) were measured in 120 CSF samples from 23 patients with pyogenic meningitis and from 11 patients with tuberculous meningitis (TBM) and in 10 CSF from subjects with non-infectious neurological diseases. The chemokine concentrations in patients with meningitis were significantly higher than in control subjects (P<0.0001). The highest CSF levels were found for IL-8 (median 2917 pg/ml) and MCP-1 (median 2557 pg/ml), whereas those of MIP-1alpha were less significantly elevated (median 24 pg/ml) (P<0.0001). Patients with pyogenic meningitis had higher levels of IL-8 and MCP-1 than those with TBM (P<0.0001). In serial samples from patients with pyogenic meningitis IL-8 levels declined before MCP-1 and MIP-alpha. In the case of TBM, IL-8, MCP-1 and MIP-1alpha decreased more gradually during treatment and were detectable in the CSF for several weeks, without any characteristic time course of elimination. These data indicate that patients with pyogenic meningitis and TBM show different chemokine profiles in CSF. The distinct chemokine pattern could be responsible for a differential attraction and activation of leucocytes in the CSF which is reflected in differences in the inflammatory response and clinical course of pyogenic meningitis and TBM.

Adult↗
PubMed1998

Rhodococcus equi infection of monocytes/macrophages from human immunodeficiency virus (HIV)-infected patients and healthy individuals: evaluation of intracellular killing and nitric oxide production.

Monocytes/macrophages from human immunodeficiency virus (HIV)-infected patients had a defect in their ability to kill Rhodococeus equi in vitro, as compared with healthy HIV-seronegative individuals. Virulent and avirulent R. equi strains isolated from humans and horses showed no significant intracellular replicative differences within both HIV-positive and -negative monocytes/macrophages. Infection with R. equi induced the production of nitric oxide (NO) by monocytes/macrophages from healthy individuals, but not by cells from HIV-positive patients. The NO formation was significantly inhibited by L-NG-monomethyl arginine and arginase. However. neither competitive inhibition of NO synthesis from L-arginine with L-NMMA nor depletion of arginine with arginase altered the killing activity of human monocytes/macrophages against R. equi, thus suggesting that L-arginine:NO pathway is not required for the intracellular antirhodococcal mechanisms of human monocytes/macrophages.

AIDS-Related Opportunistic Infections↗