Main biomarkers associated with age-related plasma zinc decrease and copper/zinc ratio in healthy elderly from ZincAge study.

PURPOSE: Zinc (Zn) plays an essential role in many biological processes including immune response. Impaired Zn status promotes immune dysfunction, and it has been associated with enhanced chronic inflammation during aging. It has been suggested that the measurement of circulating Zn by itself could not reflect the real Zn status of an individual. It is therefore necessary to identify other determinants associated with plasma Zn to better understanding how physiopathological conditions during aging may affect the concentration of this metal. METHODS: We have investigated the association between Zn levels and some biomarkers in 1090 healthy elderly from five European countries to increase the accuracy in the assessment of the Zn status. Stepwise multivariate linear regression models were used to analyze the influence of factors such as age, dietary intake, inflammatory mediators, laboratory parameters and polymorphisms previously associated with Zn homeostasis. RESULTS: Plasma Zn decrement was most strongly predicted by age, while positive correlations were found with albumin, RANTES and Zn intake after adjustment for multiple confounders. HSP70 +1267 AA genotype was an independent factor associated with Zn plasma concentrations. Cu/Zn ratio was positively associated with markers of systemic inflammation and age and negatively associated with albumin serum levels. CONCLUSIONS: Our findings show the most important independent determinants of plasma Zn concentration and Cu/Zn ratio variability in elderly population and suggest that the decline with age of Zn circulating levels is more dependent on physiopathological changes occurring with aging rather than to its nutritional intake.

Association among 1267 A/G HSP70-2, -308 G/A TNF-α polymorphisms and pro-inflammatory plasma mediators in old ZincAge population.

Proinflammatory cytokines and heat shock proteins play relevant roles in the pathogenesis of inflammatory diseases. We investigated whether Hsp70 1267 A/G and TNF-α -308 G/A polymorphisms are associated with proinflammatory mediators, zinc status and laboratory parameters in 1,078 healthy elderly from ZincAge study. Hsp70 1267 A/G genotype and allele distribution were similar among various European countries, while a TNF-α genetic heterogeneity was observed between the Northern and the Southern European populations, with a major frequency of the -308 A variant in France, Germany and Poland. We used linear regression models to test additive, dominant or recessive associations of each SNP with proinflammatory mediators, laboratory parameters, metallothioneins and zinc status. Hsp70 1267 A/G SNP, but not TNF-α -308 G/A SNP, influences TNF-α and IL-6 plasma levels under additive, dominant and recessive models (for TNF-α only). An association between Hsp70 1267 A/G SNP and zinc plasma levels was observed in the dominant model. In particular, G allele carriers showed increased circulating pro-inflammatory cytokines and zinc. Moreover, both these SNPs affect creatinine levels suggesting a possible influence on renal function. In conclusion, Hsp70 1267 A/G SNP is associated with pro-inflammatory cytokine production in healthy elderly and might represent a possible determinant of individual susceptibility to inflammatory diseases.

Human cytomegalovirus-viruria in hematopoietic stem cell transplant recipients: Context and impact.

BACKGROUND: Episodes of CMV-viruria have been reported in hematopoietic stem cell transplant (HSCT) recipients, but their context of occurrence, pathophysiology, and clinical significance remain misunderstood. METHODS: Uurine samples from 517 recipients were collected. Clinical features of recipients with or without episodes of CMV-viruria were retrospectively compared. RESULTS: CMV-viruria was detected in 15.5 % of cases. Age, sex, type of transplantation, HLA-matching, conditioning regimen, and immunosuppressive therapies did not differ between patients with and without CMV-viruria. CMV-seropositive status (R + ) was more frequent among CMV-viruric recipients. Cumulated mortality did not differ between the two groups but graft-versus-host diseases occurred more frequently among CMV-viruric patients (p = 0.04). No reduction of the estimated glomerular filtration rates was observed in CMV-viruric recipients. CONCLUSIONS: CMV-viruria primarily occurs in CMV-seropositive recipients and is not related to the degree of immunosuppression. We suggest that CMV-viruria is primarily related to the inability of the graft immune system to contain CMV-replication in R + patients. CMV-viruria is not associated with increased mortality or renal dysfunction.

Interleukin 13 inhibits human immunodeficiency virus type 1 production in primary blood-derived human macrophages in vitro.

The mechanisms by which cellular immunity maintains the asymptomatic state after human immunodeficiency virus type 1 (HIV-1) infection are poorly understood. CD4+ T lymphocytes play a complex role in regulating anti-HIV effector pathways, including activation of macrophages, which are themselves implicated in clinical latency and pathogenesis of symptomatic acquired immune deficiency syndrome. We have found that a newly identified T helper type 2 lymphokine, interleukin 13 (IL-13), inhibits HIV-1ADA and Ba-L replication in primary tissue culture-derived macrophages but not in peripheral blood lymphocytes. Viral production in cells was measured by viral protein (p24) and reverse transcriptase levels, while entry was assessed by proviral DNA analysis at timed intervals after infection. Inhibition by IL-13 was dose and time dependent and not mediated through altered viral entry, reverse transcription, or viral release. IL-13 is therefore a candidate cytokine for the suppression of HIV infection within monocytes and macrophages in vivo.

Immune hyperactivation of HIV-1-infected T cells mediated by Tat and the CD28 pathway.

Human immunodeficiency virus-type 1 (HIV-1) infection is characterized by a chronic state of immune hyperactivation in patients. Infection of human peripheral blood lymphocytes with HIV-1 in vitro resulted in increased interleukin-2 (IL-2) secretion in response to T cell activation via the CD3 and CD28 receptors. Expression of the HIV-1 transactivator Tat recapitulated this phenotype and was associated with increased IL-2 secretion in response to costimulation with CD3 plus CD28. IL-2 superinduction by Tat occurred at the transcriptional level, was mediated by the CD28-responsive element in the IL-2 promoter, and was exclusively dependent on the 29 amino acids encoded by the second exon of Tat.

Effects of zinc supplementation on antioxidant enzyme activities in healthy old subjects.

A large body of experimental research indicates that oxidative stress contributes to the processes related to aging and age-related diseases. Trace elements, particularly zinc (Zn), are essential components of the endogenous enzymatic antioxidant defenses. The aim of this study was to determine the activity of three main antioxidant enzymes in plasma [i.e. superoxide dismutase (pSOD), catalase (CAT), glutathione peroxidase (GPx)] and of SOD in erythrocyte (eSOD) in a group of 1108 healthy elderly subjects from different European countries. The same enzymatic activities were evaluated in a subgroup of 108 subjects before and after Zn supplementation. We observed that eSOD activity increased with age, whereas plasma Zn decreased. Moreover, we found that women showed higher eSOD activity and lower plasma Zn compared to men. There were no age and gender-related differences in the activities of pSOD, CAT and GPx. After Zn supplementation, the activities of Zn-dependent enzymes (pSOD and eSOD), as well as plasma Zn concentration, were significantly higher than before supplementation. These results were not influenced by age, gender, plasma Zn variations (Delta Zn) and geographic area. These data suggest the potential beneficial effects of Zn supplementation on Zn-dependent antioxidant enzymes in healthy elderly subjects.

Severe systemic cytomegalovirus infections in patients with steroid-refractory ulcerative colitis treated by an oral microemulsion form of cyclosporine: report of two cases.

CMV reactivation is frequently observed in acute flares of ulcerative colitis (UC), particularly those which do not respond to intravenous steroids. Several recent series have suggested that, in most cases, CMV reactivation does not lead to severe complications and resolves spontaneously with the UC flare and discontinuation of immunosuppression. In the present paper, we describe two patients with active UC who developed a severe systemic CMV infection during a treatment with an oral microemulsion form of cyclosporine. This is of concern, particularly in a context of increasing use of immunosuppressive drugs in UC. We propose a prophylactic and curative approach to decrease morbidity related to CMV infection in active UC.

Cytomegalovirus, Macrophages and Breast Cancer.

The human cytomegalovirus (HCMV) is a betaherpesvirus that is highly host specific, infects among others epithelial cells and macrophages, and has been recently mentioned as having oncomodulatory properties. HCMV is detected in the breast tumor tissue where macrophages, especially tumor associated macrophages, are associated with a poor prognosis. In this review, we will discuss the potential implication of HCMV in breast cancer with emphasis on the role played by macrophages.

Cytokine receptor signalling and aging.

With ageing the immune system is deregulated and this leads to the development of immunosenescence mainly affecting the adaptive immune response. There is much knowledge accumulated concerning various receptor functions and signalling with ageing such as TCR, FcRs, TLRs. Cytokines are playing a major role in haematopoietic cell functions and in the harmonious and integrated coordination of the innate and adaptive immune response. There exists a large amount of data on cytokine production changes with ageing, as IL-2 production is decreasing, while IL-6 production is increasing. In contrast, there is only scarce knowledge concerning the cytokine receptors and their signalling in ageing. However, there is some evidence that the signalling of IL-2 receptors is altered in T cells and macrophages, mainly in relation to the JAK/STAT pathway. We present here evidence that the IL-6 induced signalling is also altered in T cells with ageing. An alteration in the JAKs and STATs activations in T cells and macrophages was demonstrated. The exact cause of these altered activations is not known and future studies are needed to elucidate them. In this review we summarise our present knowledge on cytokine signalling with ageing, mainly focusing on IL-2 and IL-6 receptors signalling.

Macrophage activation and HIV infection: can the Trojan horse turn into a fortress?

Macrophages are infected early during HIV infection and are thought to play the role of a Trojan horse by spreading infection in tissues. Most recent studies point out to a more complex role for macrophages in HIV infection: macrophages could contribute to both host defense and viral persistence and pathogenesis. Infected macrophages are a reservoir for HIV and modulate apoptosis of T cells present in their vicinity. Also, a functional impairment of HIV-infected macrophages may play a role in AIDS pathogenesis. Nevertheless, both activation and differentiation of monocyte/macrophages can interfere with susceptibility of these cells to infection. Therefore, a wide variety of stimuli result in HIV suppression through macrophage activation. At present times, a dynamic view on the role of macrophages in HIV infection arises which indicates that macrophages are a target for the virus and at the same time regulate its replication. Therefore, macrophages are at the cross-road between protection and pathogenesis in HIV infection due to their involvement both as a viral target and a key modulator of non-specific and specific immune responses. Future studies will help unravel the cellular and molecular mechanisms that underlie HIV-macrophage interactions and might result in new vaccine and/or therapeutic strategies.

Comparison of p24 measurement by ELISA versus indicator cells for detecting residual HIV infectivity in vitro.

Inactivation of HIV-1 contaminated materials or biological samples is of great importance and requires the use of a reliable assay to detect residual infectivity. In this study we treated cell-free or cell-associated (monocyte-derived macrophages) HIV-1 with two chemicals known for their antiviral activities, beta-propiolactone (beta PL) and formaldehyde (FO), and tested it for the presence of residual infectivity. HIV-1 infected primary monocyte-derived macrophages (MDM) or cell-free HIV-1 were fixed with increasing concentrations of either beta PL or FO for 1 day at 4 degrees C. Then either fresh primary MDM or fresh medium was added, and the supernatant p24 levels were assayed up to 12 days after infection. All the supernatants harvested were added to indicator cells, fresh primary MDM, to assess for residual infectivity. The results show that p24 measurement is not a reliable assay for the detection of residual infectious virions after chemical fixation of HIV-infected primary MDM. In contrast, the use of indicator primary cells (MDM) is a much more sensitive and reliable assay. By performing an indicator cell assay we showed that FO efficiently inactivates cell-associated and cell-free HIV-1 at concentrations as low as 1% v/v. In contrast beta PL is more efficient in inactivating cell-free than cell-associated virus and does not inactivate cell-associated HIV-1 at concentrations as high as 1% v/v.

Blockade of BFA-mediated apoptosis in macrophages by the HIV-1 Nef protein.

HIV-1 Nef protein has key roles at almost all stages of the viral life cycle. We assessed the role of Nef and of the translation elongation factor eEF1A in primary human macrophages. Nuclear retention experiments and inhibition of the exportin-t (Exp-t) pathway suggested that cytoplasmic relocalization of eEF1A, mediated by Exp-t occurs in Nef-treated monocyte-derived macrophages (MDMs). We observed the presence of tRNA in the Nef/eEF1A complexes. Nucleocytoplasmic relocalization of the Nef/eEF1A complexes prevented stress-induced apoptosis of MDMs treated with brefeldin A. Blockade of stress-induced apoptosis of MDMs treated with HIV-1 Nef resulted from enhanced nucleocytoplasmic transport of eEF1A with decreased release of mitochondrial cytochrome c, and from increased tRNA binding to cytochrome c, ultimately leading to an inhibition of caspase activation. Our results indicate that HIV-1 Nef, through the nucleocytoplasmic relocalization of eEF1A and tRNAs, enhances resistance to stress-induced apoptosis in primary human macrophages.

Molecular Understanding of HIV-1 Latency.

The introduction of highly active antiretroviral therapy (HAART) has been an important breakthrough in the treatment of HIV-1 infection and has also a powerful tool to upset the equilibrium of viral production and HIV-1 pathogenesis. Despite the advent of potent combinations of this therapy, the long-lived HIV-1 reservoirs like cells from monocyte-macrophage lineage and resting memory CD4+ T cells which are established early during primary infection constitute a major obstacle to virus eradication. Further HAART interruption leads to immediate rebound viremia from latent reservoirs. This paper focuses on the essentials of the molecular mechanisms for the establishment of HIV-1 latency with special concern to present and future possible treatment strategies to completely purge and target viral persistence in the reservoirs.

Inhibition of ER stress-mediated apoptosis in macrophages by nuclear-cytoplasmic relocalization of eEF1A by the HIV-1 Nef protein.

HIV-1 Nef protein has key roles at almost all stages of the viral life cycle. We assessed the role of the Nef/eEF1A (eukaryotic translation elongation factor 1-alpha) complex in nucleocytoplasmic shuttling in primary human macrophages. Nuclear retention experiments and inhibition of the exportin-t (Exp-t) pathway suggested that cytoplasmic relocalization of eEF1A, mediated by Exp-t, occurs in Nef-treated monocyte-derived macrophages (MDMs). We observed the presence of tRNA in the Nef/eEF1A complexes. Nucleocytoplasmic relocalization of the Nef/eEF1A complexes prevented stress-induced apoptosis of MDMs treated with brefeldin-A. Blockade of stress-induced apoptosis of MDMs treated with HIV-1 Nef resulted from enhanced nucleocytoplasmic transport of eEF1A with decreased release of mitochondrial cytochrome c, and from increased tRNA binding to cytochrome c, ultimately leading to an inhibition of caspase activation. Our results indicate that HIV-1 Nef, through the nucleocytoplasmic relocalization of eEF1A and tRNAs, enhances resistance to stress-induced apoptosis in primary human macrophages.

Cytokines, viruses and macrophages: an interactive network. An immune dysregulation involving the members of the tumor necrosis factor (TNF) receptor superfamily could be critical in AIDS pathogenesis.

Both macrophages and cytokines are components of the immune defense against viral infections. Among cytokines, interferons have been the most studied and interferon-gamma which is secreted by T cells and NK cells activates macrophages which synthesize both interferon-alpha and -beta which have powerful antiviral activity. Aside from interferons other cytokines such as tumor necrosis factor-alpha and transforming growth factor-beta display an antiviral activity. Nevertheless often cytokines could mediate distinct actions in regard to viral infection and this has been demonstrated extensively in AIDS pathogenesis. We reviewed among others the interactions between human immunodeficiency virus type-1, macrophages and cytokines and would like to forward a new model for AIDS pathogenesis based on the involvement of the TNF receptor superfamily.

55- and 75-kilodalton tumor necrosis factor receptors mediate distinct actions in regard to human immunodeficiency virus type 1 replication in primary human macrophages.

We report in this study that repeated tumor necrosis factor alpha (TNF-alpha) pretreatment, starting before and continued after infection by human immunodeficiency virus type 1 (HIV-1), inhibits replication of the monocytotropic Ada strain in primary tissue culture-differentiated macrophages (TCDM), as assessed by sixfold lower levels of reverse transcriptase (RT) activity than that in untreated cells and absence of syncytium formation in TCDM cultures. In order to determine the pathways involved in inhibition of HIV-1 replication in primary TCDM pretreated with TNF-alpha, we tested TNF-alpha mutants T55 and T75, which recognize either the 55-kDa (TNF-R1) or the 75-kDa (TNF-R2) TNF receptor, respectively. Pretreatment of TCDM with the T75 mutant decreased the RT activity compared with that in untreated infected control cells fivefold and almost totally inhibited syncytium formation. In contrast, when TCDM were pretreated with the T55 mutant alone, syncytia were observed and RT activity was decreased about one-half. These results suggest that the inhibition of HIV-1 replication in TCDM pretreated with TNF-alpha might be mediated mainly through the 75-kDa TNF receptor (TNF-R2) rather than through the 55-kDa receptor (TNF-R1). Inhibition of HIV-1 replication in TCDM was observed with both T75 mutant pretreatment and posttreatment, starting at 1 h or 3 days after infection, whereas posttreatment with the T55 mutant, but not pretreatment, stimulated HIV-1 growth in primary TCDM. Both pre- and posttreatment with TNF-alpha inhibited HIV-1 replication in primary TCDM. The stimulation of HIV-1 replication by TNF-alpha in a chronically infected promonocytic cell line, U1, which contains two copies of integrated provirus, was mediated through the 55-kDa TNF-R1 alone and not through the 75-kDa TNF-R2. These results demonstrate that the 55-kDa TNF-R1 is involved in postintegration stimulation of HIV-1 while the 75-kDa TNF-R2 is involved in the inhibition of an early step of the viral life cycle in primary human TCDM.

Macrophages and T-cell apoptosis in HIV infection: a leading role for accessory cells?

Recent studies indicate that macrophages modulate T-cell apoptosis in HIV infection. Macrophages have been shown to trigger apoptosis of uninfected bystander T cells and to protect HIV-infected T cells from apoptosis. This article raises the possibility that macrophages, via modulation of T-cell apoptosis, play a crucial role in both immune suppression and the formation of viral reservoirs during HIV infection.

Tumor necrosis factor (TNF)-alpha and TNF receptors in viral pathogenesis.

Tumor necrosis factor-alpha (TNF-alpha) and TNF receptors (TNFR) are members of the growing TNF ligand and receptor families that are involved in immune regulation. The present report will focus on the role of the prototypic ligand TNF and its two receptors, TNFR1 and TNFR2, in viral pathogenesis. Although TNF was reported years ago to modulate viral infections, recent findings on the molecular pathways involved in TNFR signaling have allowed a better understanding of the molecular interactions between cellular and viral factors within the infected cell. The interactions of viral proteins with intracellular components downstream of the TNFR have highlighted at the molecular level how viruses can manipulate the cellular machinery to escape the immune response and to favor the spread of the infection. We will review here the role of TNF and TNFR in immune response and the role of TNF and TNFR signaling in viral pathogenesis.

PCR analysis of HIV1 infection of macrophages: virus entry is CD4-dependent.

Amplification of early reverse transcripts by the polymerase chain reaction has been used to measure HIV1 entry into H9 cells and primary macrophages. With a single-step method of DNA preparation, we performed time course experiments to follow the appearance of long terminal repeat DNA. In both cell types, the formation of DNA was completely inhibited by anti-CD4 antibody, confirming the requirement of CD4 for virus binding and entry, and demonstrating that there were no CD4-independent routes of infection. In agreement with previous infectivity studies, sCD4 inhibited the entry of IIIB into H9, but only partially blocked Ba-L into macrophage when used at a comparable dose.