Systemic effects of locally injected platelet rich plasma in a rat model: an analysis on muscle and bloodstream.

Abundant evidence suggests that growth factors, contained in platelets alpha granules, may play a key role in the early stages of the muscle healing process with particular regard to the inflammatory phase. Although the contents of the platelet-rich plasma preparations have been extensively studied, the biological mechanisms involved as well as the systemic effects and the related potential doping implications of this approach are still largely unknown. The aim of the present study was to investigate whether local platelet-rich plasma administration may modify the levels of specific cytokines and growth factors both in treated muscle and bloodstream in rats. An additional aim was to investigate more deeply whether the local platelet-rich plasma administration may exert systemic effects by analyzing contralateral lesioned but untreated muscles. The results showed that platelet-rich plasma treatment induced a modification of certain cytokines and growth factor levels in muscle but not in the bloodstream, suggesting that local platelet-rich plasma treatment influenced directly or, more plausibly, indirectly the synthesis or recruitment of cytokines and growth factors at the site of injury. Moreover, the observed modifications of cytokine and growth factor levels in contralateral injured but not treated muscles, strongly suggested a systemic effect of locally injected platelet-rich plasma.

HIV DNA loads, plasma residual viraemia and risk of virological rebound in heavily treated, virologically suppressed HIV-infected patients.

In this single-centre, retrospective study, we analyzed data of 194 patients receiving antiretroviral therapy with <50 human immunodeficiency virus (HIV) RNA copies/mL in plasma and 318 HIV RNA/DNA paired samples. By kinetic polymerase chain reaction (kPCR) molecular system analysis, 104 (54%) subjects had undetectable HIV RNA and 90 (46%) had residual viraemia. Median (interquartile range) HIV DNA load was 780 (380-1930) copies/10(6) peripheral blood lymphocytes (PBL), and HIV DNA loads were independently associated with residual viraemia (p 0.002). Virological rebound occurred in 29/194 (15%) patients over a median (interquartile range) follow-up of 17.5 (13.5-31.5) months. Residual viraemia (p 0.002), but not HIV DNA load, was independently associated with virological rebound.

Steroid resistance in nasal polyposis: role of glucocorticoid receptor and TGF-beta1.

BACKGROUND: Glucocorticoids (GCs) are considered drugs of choice for treating nasal polyps (NPs). However, a subset of patients shows a limited clinical response even to high doses of GCs. Altered expression of glucocorticoid receptors (GRs), namely GR-alpha; and GR-beta;, is a potential mechanism underlying GC insensitivity. GCs modulate the expression of several cytokines, including transforming growth factor-beta (TGF-beta), which may contribute to cellular proliferation in NPs. The study investigates some biomolecular features of GC-resistant NPs, and examines possible differences from normal mucosa (NM). METHODOLOGY: Radioligand binding assay (binding) was used to determine GR-alpha; binding capacity; Western blotting was used to evaluate GR-alpha;, GR-beta;, and TGF-beta; expression and GR-alpha; subcellular distribution. NPs were sampled in 32 patients during ethmoidectomy; NM was taken from 15 healthy patients during rhinoplasty. RESULTS: GR-alpha; was present in NPs and NM, with lower affinity for the ligand in NPs. GR-alpha; was prevalent in the cytosol of NPs that were GR-alpha-negative to the binding assay. GR-beta was expressed in NPs and absent in the majority of NM. TGF-beta1 expression was higher in NPs than in NM. CONCLUSIONS: GR-beta and TGF-beta1 might be involved in NP pathogenesis, but their role in modulating GC sensitivity is still unclear.

Rapid determination of anti-estrogens by gas chromatography/mass spectrometry in urine: Method validation and application to real samples.

A fast screening protocol was developed for the simultaneous determination of nine anti-estrogenic agents (aminoglutethimide, anastrozole, clomiphene, drostanolone, formestane, letrozole, mesterolone, tamoxifen, testolactone) plus five of their metabolites in human urine. After an enzymatic hydrolysis, these compounds can be extracted simultaneously from urine with a simple liquid-liquid extraction at alkaline conditions. The analytes were subsequently analyzed by fast-gas chromatography/mass spectrometry (fast-GC/MS) after derivatization. The use of a short column, high-flow carrier gas velocity and fast temperature ramping produced an efficient separation of all analytes in about 4 min, allowing a processing rate of 10 samples/h. The present analytical method was validated according to UNI EN ISO/IEC 17025 guidelines for qualitative methods. The range of investigated parameters included the limit of detection, selectivity, linearity, repeatability, robustness and extraction efficiency. High MS-sampling rate, using a benchtop quadrupole mass analyzer, resulted in accurate peak shape definition under both scan and selected ion monitoring modes, and high sensitivity in the latter mode. Therefore, the performances of the method are comparable to the ones obtainable from traditional GC/MS analysis. The method was successfully tested on real samples arising from clinical treatments of hospitalized patients and could profitably be used for clinical studies on anti-estrogenic drug administration.

Ischemia/reperfusion injury is increased and cardioprotection by a postconditioning protocol is lost as cardiac hypertrophy develops in nandrolone treated rats.

We hypothesized that nandrolone (ND)-abuse induces cardiac hypertrophy, increases myocardial susceptibility to ischemia/reperfusion (I/R) injury, and reduces responsiveness to postconditioning (PostC) cardioprotection. Wistar-rats were ND treated for 2 weeks (short_ND) or 10 weeks (long_ND). Vehicle-treated rats served as controls. Hearts were retrogradely perfused and left ventricular pressure (LVP) was measured before and after 30-min global ischemia. In subgroups of hearts, to induce cardioprotection a PostC protocol (five cycles of 10-s reperfusion and 10-s ischemia) was performed. ß-adrenoreceptors, kinases (Akt and GSK-3ß) and phosphatases (PP2A sub A and PP2A sub B) were examined by Western blot before and after ischemia. After 120-min reperfusion, infarct size was measured. Short_ND slightly increased cardiac/body weight ratio, but did not affect cardiac baseline nor post-ischemic contractile function or infarct size when compared to vehicle hearts. However, PostC limited cardiac dysfunction much more in short_ND hearts than the other groups. Although cardiac/body weight ratio markedly increased after long_ND, baseline LVP was not affected. Yet, post-ischemic contracture and infarct size were exacerbated and PostC was unable to reduce infarct size and ventricular dysfunction. While short_ND increased phosphatases, non-phosphorylated and phosphorylated Akt, long_ND reduced phosphatase-expression and Akt phosphorylation. Both short_ND and long_ND had no effect on the GSK-3ß-phosphorylation but increased the expression of ß(2)-adrenoreceptors. In reperfusion, PostC increased Akt phosphorylation regardless of protective effects, but reduced phosphatase-expression in protected hearts only. In conclusion, short_ND improves post-ischemic myocardial performance in postconditioned hearts. However, long_ND increases myocardial susceptibility to I/R injury and abolishes cardioprotection by PostC. This increased susceptibility might be related to steroid-induced hypertrophy and/or to altered enzyme expression/phosphorylation.

Persistence of CCR5 usage among primary human immunodeficiency virus isolates of individuals receiving intermittent interleukin-2.

OBJECTIVE: To investigate the impact of intermittent interleukin-2 (IL-2) plus combination antiretroviral therapy (cART) on HIV-1 entry co-receptor use. METHODS: Primary HIV-1 isolates were obtained from 54 HIV-1-positive individuals at baseline and after 12 months using co-cultivation of peripheral blood mononuclear cells (PBMC) with activated PBMC of HIV-negative healthy donors. HIV-1 co-receptor use was determined on U87-CD4 cells. RESULTS: Fourteen out of the 21 (67%) IL-2-treated individuals harbouring a primary CCR5-dependent (R5) HIV-1 isolate at baseline confirmed an R5 virus isolation after 12 months in contrast to 3 out of 7 (43%) of those receiving cART only. After 12 months, only 1 R5X4 HIV-1 isolate was obtained from 21 cART+IL-2-treated individuals infected with an R5 virus at entry (5%) vs. 2/7 (29%) patients receiving cART alone, as confirmed by a 5-year follow-up on some individuals. CONCLUSIONS: Intermittent IL-2 administration plus cART may prevent evolution towards CXCR4 usage in individuals infected with R5 HIV-1.

Synergistic effects against post-ischemic cardiac dysfunction by sub-chronic nandrolone pretreatment and postconditioning: role of beta2-adrenoceptor.

Beta(2)-adrenoreceptor overexpression is beneficial against ischemia/reperfusion (I/R) injury. Whether beta-adrenoreceptors are involved in postconditioning (PostC) is unknown. We investigated whether nandrolone-decanoate (ND)-pretreatment can modulate (1) beta-adrenoreceptor expression and (2) post-ischemic cardiac function in response to I/R and PostC. Finally, we tested whether cardioprotection can be prevented by the inhibition of beta(2)-adrenoreceptors. Isolated rat hearts from ND pretreated (15 mg/kg/day i.m., for 14 days) and untreated-animals underwent 30-min ischemia and 120-min reperfusion. In subgroups, at the end of ischemia a PostC protocol (five cycles of 10-s reperfusion and 10-s ischemia) was applied and/or a beta(2)-adrenoreceptor blocker, ICI-118.551 (10 microM), was infused. Left ventricular pressure (LVP) was measured with an electromanometer, and infarct-size was evaluated using nitro-blue-tetrazolium staining. ND-pretreatment increased beta(2)-adrenoreceptor expression, but did not alter cardiac-weight, LVP and maximum rate of increase of LVP (dP/dt(max)). After I/R, infarct-size was smaller in ND-pretreatment than in untreated-animals. Infarct-size was also reduced by PostC, both in untreated and ND-pretreated animals. Contracture was less marked in ND-pretreated animals. PostC reduced contracture in both ND-pretreated and untreated hearts. Moreover, PostC improved post-ischemic recovery of developed LVP and dP/dt(max) much more in earts of ND-pretreated than untreated-animals. ICI-118.551 abolished ND protection and PostC-protection both in ND-pretreated and untreated hearts. Data show that two-weeks ND-pretreatment induces 1) an overexpression of beta(2)-ARs without cardiac hypertrophy and 2) improves the post-ischemic diastolic and systolic cardiac function. Intriguingly, ND-pretreatment potentiates the improvement of systolic function induced by postconditioning via beta(2)-adrenoreceptor activation.

Phylogenetic internal control for HIV-1 genotypic antiretroviral testing.

Genotypic testing includes several steps (RNA purification, RT-PCR amplification, DNA sequencing, sequence editing and analysis) that should be individually controlled. In our laboratory, we have added to this step-by-step internal control a final phylogenetic quality control: this is performed every time a sequence is obtained from a patient previously subjected to the same test. Each sequence with this characteristic is routinely compared with sequences from previous samples of the same patient by multiple alignment and a neighbor-joining tree by using Kimura two-parameter method is constructed. To validate the quality control procedure, we have aligned and calculated the mean similarity of the reverse transcriptase (first 984 nucleotides) and protease (whole gene) sequences from 30 patients whose virus was completely wild-type for both reverse transcriptase and protease. In the same tree, we have added the sequences obtained from 5 out of the 30 patients, tested at a second time point. The wild type sequences have shown a mean inter-sample divergence of 2.9%, and all the sequence pairs from individual patients clustered together in the tree constructed with the nucleotide sequences, while the tree constructed with the inferred aminoacid sequences did not always permit to cluster the sequences from the same patients. This indicates that: 1) the phylogenetic analysis of nucleic acid sequences can be useful to rule out sample mix-up; 2) the belonging of a sequence to each individual patient can efficiently be assessed also in the cases of extreme divergence in terms of drug resistance mutations.

Characterization of GBV-C infection in HIV-1 infected patients.

BACKGROUND: GB virus C, a positive-stranded RNA virus, is classified in the family Flaviviridae. It is currently believed that persistent infection occurs in 25-50% of infected individuals, however, it still remains an "orphan" virus in search of a role in human pathology. Molecular epidemiological studies have demonstrated that GBV-C infection is present in about 1-1.4% of the healthy population in developed countries, that it shares routes of transmission with HIV and HCV and that the prevalence of GBV-C in these populations is higher than in blood donors. On the basis of the sequence variation among the isolates, GBV-C is classified into at least four major genotypes. Preliminary evidence has suggested that GBV-C is a lymphotropic virus that replicates mainly in the spleen and bone marrow. Recently, several reports have investigated the possible beneficial effect of GBV-C co-infection on HIV disease progression to AIDS, reduced mortality in HIV infected individuals and lower HIV viral loads, not leading to a definitive conclusion yet. AIM: To investigate the role of GBV virus C co-infection in two different subsets of HIV-infected patients, and to evaluate the prevalence of GBV-C genotypes in Northern Italy. METHODS: A total of 86 HIV positive patients were examined for GBV-C viremia (years after HIV sera conversion: 12 +/- 5). Control population (Group A): 46 patients (mean age 42 years) with <200CD4/ml during the observation period. Longterm non progressor population (Group B): 40 patients, (mean age 40 years) with >500 CD4/ml for at least 8 years and never treated with HAART. After extraction of viral RNA from plasma samples, amplification of a highly conserved region of 5'UTR was performed by nested RT-PCR. All positive samples were genotyped by sequencing, alignment with published sequences and phylogenetic analysis. CD4 cell count, HIV plasma levels were also evaluated. RESULTS: 9 out of 46 (19.56%) in Group A and 15 out of 40 (37.5%) in Group B had detectable GBV-C viremia (p=0.064, OR 2.47, percent confidence interval 0.94 to 6.51). No statistical difference was observed when disease stage was evaluated between the two groups. In Group B, after regression analysis for CD4 cell count decrease over the period observed, no significant difference was detected between GBV-C positive and negative patients. No significant difference was observed in Group B in HIV viremia and CD4 cell count at time of GBV-C detection between GBV-C infected patients and GBV-C negative patients. All Italian patients were genotype 2, the only African patient carried GBV-C genotype 1. CONCLUSIONS: Although previous results suggest that GBV-C virus may be a favorable marker for long term non progression of HIV disease, whether it plays a direct anti-HIV role or just takes advantage of non progessors' higher CD4 cell count to replicate more efficiently, still remains to be answered. Follow up of untreated patients and further evaluation of virological interactions, between the viruses and the host immune system, will be helpful to shed some light on these observations, offering new prognostic and eventually therapeutical tools for the management of HIV patients.

Autocrine down-regulation of glucocorticoid receptors by interleukin-11 in human osteoblast-like cell lines.

It has recently been suggested that interleukin (IL)-11 plays a role in the pathogenesis of glucocorticoid (GC)-induced osteoporosis. IL-11 belongs to the gp130 cytokine family, which includes also IL-6. We have previously investigated GC-IL-6 interplay, showing that GC inhibits IL-6 release and IL-6 up-regulates GC receptor (GR) numbers in the human osteoblast-like cell lines Saos-2 and MG-63, which constitutively have an opposite pattern of expression for GR, IL-11, IL-6, alkaline phosphatase and osteoprotegerin (OPG). The aim of this study was to investigate GC-IL-11 interplay in the same two cell lines. First, cells were incubated with cortisol (0.01-1 microM) for 20 h in the presence and in the absence of a known IL-11 secretagogue (IL-1beta); cell media were assayed for IL-11 by ELISA. Secondly, cells were incubated with IL-11 (0.1-100 ng/ml) or specific anti-IL-11 monoclonal antibody for 20 h, and then assayed for GR by a radioligand binding assay. Similar to IL-6, both constitutive and IL-1beta-inducible IL-11 release were dose-dependently inhibited by cortisol (P<0.01); at variance with IL-6, exogenous IL-11 dose-dependently decreased GR numbers in MG-63 cells (P<0.05), while anti-IL-11 antibody significantly increased GR numbers in both cell lines (P<0.05). IL-11-induced reduction of GR in MG-63 cells was confirmed by Western blot analysis. While exerting opposite effects on GR numbers, neither IL-6 nor IL-11 significantly modified GC-dependent inhibition of OPG release. Our data indicate that even physiological concentrations of cortisol negatively modulate IL-11 secretion and demonstrate, for the first time, an inhibitory effect of the cytokine on GR. Thus, the concept of autocrine-paracrine loops that modulate GC action and involve gp130 cytokines is corroborated. These loops could have clinical relevance for the dynamics of bone loss in patients given GC and having high concentrations of these cytokines in the bone microenvironment.

Interactions between glucocorticoids and cytokines in the bone microenvironment.

Cytokines belonging to the so-called interleukin-6 (IL-6) or gp130 cytokine family, notably IL-6 and IL-11, are known as pro-resorptive cytokines, in that they promote osteoclastogenesis. Glucocorticoid (GC)-induced osteoporosis is admittedly the most frequent secondary osteoporosis. The pathogenesis still has many unresolved issues. Although the effects of GCs on cytokine production and recognition have been extensively studied, little is known about the effects of cytokines on GC action at the target level. We have focused on the effects of IL-6 and IL-11 on specific binding by type II GC receptors (GRs) in two human osteoblast-like cell lines (Saos-2 and MG-63) that have remarkably different constitutive expression of these cytokines and GRs as well. We have provided evidence that IL-6 upregulates GR binding sites, while IL-11 downregulates these sites, as determined by radioligand binding assay and Scatchard analysis. GR affinity (K(d)) did not change after exposure to both cytokines. A number of experiments were consistent with the view that in human osteoblast-like cells, cytokines of the IL-6 family have autocrine modulatory effects on GRalpha (GRbeta is a variant that does not bind specifically in our method). Complex effects of GCs on the system(s) of proinflammatory/anti-inflammatory cytokines and conversely of these cytokines on GC action could account for the dynamics of bone loss in patients given GCs and conceivably having high concentrations of these cytokines in the bone microenvironment.

Inhibitory effect of physiological concentrations of cortisol but not estradiol on interleukin (IL)-6 production by human osteoblast-like cell lines with different constitutive IL-6 expression.

Estrogen deficiency and glucocorticoid excess are two well-known conditions that account for osteoporosis. Interleukin (IL)-6 plays an important role in bone resorption; both estrogens and glucocorticoids are credited with an inhibitory effect on osteoblast production of IL-6. The aim of the study was to investigate whether endogenous hormones, which lead to opposite changes in bone mass, have a common inhibitory effect upon constitutive and inducible IL-6 production by human osteoblast-like cells. We used two human osteosarcoma cell lines (MG-63 and Saos-2) with a different degree of differentiation and constitutive production of IL-6 [2587+/-536 (mean+/-SE) and 3.65+/-0.06 pg/10(6) cells, respectively]. We examined the effects of physiological and supraphysiological concentrations of 17beta-estradiol (E2) and cortisol on basal and IL-1beta-induced IL-6 release in the medium. In all experimental conditions, cellular estrogen receptors (ERs) and glucocorticoid receptors (GRs) were measured by binding assay. Both MG-63 and Saos-2 cell lines had measurable GRs (106 300+/-24 996 and 18 100+/-3215 binding sites/cell, respectively) and ERs (2197+/-377 and 1261+/-66.5 binding sites/cell, respectively). In MG-63 cells, cortisol treatment for 20 h decreased both basal and IL-1beta-induced IL-6 release in a dose-dependent manner; in Saos-2 cells the same effect was apparent for IL-1beta-induced release. Mifepristone (RU-486) did function as partial agonist and antagonist of cortisol. At variance with cortisol, E2 did not exert any effect on IL-6 secretion. Treatment with 1,25(OH)2D3 increased by 100-200% ER concentrations, but did not change ineffectiveness of E2 in modifying IL-6 production; furthermore, when E2 was combined with cortisol, there was no additive effect on cortisol-induced inhibition. The dissociation between glucocorticoid and estrogen effects observed in these human cell lines is a sufficiently robust phenomenon to raise questions about the pathogenetic role of IL-6 in osteoporosis associated with estrogen deficiency. Conversely inhibition of osteoblast production of IL-6 may offer an explanation why bone resorption is not the dominant factor in the pathogenesis of glucocorticoid-induced osteoporosis.

Effect of genotypic resistance on the virological response to highly active antiretroviral therapy in cerebrospinal fluid.

Paired plasma and cerebrospinal fluid (CSF) specimens drawn from 15 HIV-infected patients with neurological disease before and after a median 6-week duration of highly active antiretroviral therapy (HAART) were studied to assess the short-term virological response of CSF and whether this can be predicted on the basis of baseline resistance mutations. After treatment, the median plasma and CSF viral load (VL) decreased by, respectively, 2.08 log10 (p = 0.0001) and 0.91 log10 copies/ml (p = 0.007) in comparison with baseline. A plasma virological response was observed in all but one patient, whereas the posttreatment CSF VL increased, remained unchanged, or decreased at a substantial lower rate than in plasma of six "CSF non/slow responders" (40%). Direct sequencing of baseline specimens showed that none of these patients had reverse transcriptase (RT) or primary protease resistance mutations in the CSF alone, but two had RT mutations conferring high-level resistance to drugs included in the HAART regimen in both CSF and plasma. The other four patients had no RT or primary protease resistance mutations. There was no significant difference in the nucleotide diversity of the CSF and plasma RT sequences, baseline plasma or CSF VL, the CSF-to-plasma VL ratio, the number of CSF cells, the CD4+ cell counts, or the history of antiretroviral treatment between the CSF non-slow responders and the other patients. During this short-term follow-up and despite a plasma response, a significant proportion of HAART-treated patients with neurological symptoms showed a slow or absent CSF response. Most of these cases were not associated with the presence of resistant HIV strains in the CSF.

Efficacy of low-dose intermittent subcutaneous interleukin (IL)--2 in antiviral drug--experienced human immunodeficiency virus--infected persons with detectable virus load: a controlled study of 3 il-2 regimens with antiviral drug therapy.

To evaluate the safety and efficacy of 3 regimens of intermittent subcutaneous (sc) interleukin (IL)--2 in a phase 2 study, 61 antiviral drug-experienced human immunodeficiency virus (HIV)--positive patients were randomly assigned to one of the following study arms: antiretroviral therapy (ART) plus IL-2 (12 million IU [MIU] by continuous intravenous infusion, followed by 7.5 MIU twice a day, sc, every 8 weeks); ART plus IL-2 (7.5 MIU twice a day, sc, every 8 weeks); ART plus IL-2 (3 MIU twice a day, sc, every 4 weeks); or ART alone. A significant increase of circulating CD4 cells was observed in IL-2--treated subjects, compared with those given ART alone. Low doses of IL-2 were better tolerated. Despite the incomplete suppression of viral replication, IL-2 with ART did not increase either plasma viremia or cell-associated HIV DNA levels. Low doses of intermittent sc IL-2 induced a stable increase of peripheral CD4 cells that was indistinguishable from those associated with higher, less well-tolerated doses of IL-2.

Autocrine up-regulation of glucocorticoid receptors by interleukin-6 in human osteoblast-like cells.

Interleukin (IL)-6 is a bone-resorbing cytokine that acts primarily on osteoclast progenitors to stimulate both proliferation and differentiation. Glucocorticoids (GC) down-regulate IL-6 synthesis in different cell types, including osteoblasts. Given the fact that bone remodeling is a tightly controlled process, it is reasonable to think of auto-regulatory mechanisms in the bone microenvironment able to prevent excess IL-6 production. We have studied two human osteosarcoma cell lines (Saos-2 and MG-63) with different degrees of differentiation and different constitutive IL-6 production (3.4 +/- 0.2 (mean +/- SE) and 2,898 +/- 401 pg/10(6) cells, respectively). We measured the expression of glucocorticoid receptor (GR) in terms of specific binding sites after exposure of cells to different amounts of IL-6. Incubation for 20 hours with IL-6 at increasing concentrations up to 2,000 pg/ml yielded significant increase of GR binding sites in both cell lines. IL-6 was also able to revert the inhibitory effect of dexamethasone (1 microM) on GR in both cell lines. In MG-63 cells, that express higher concentrations of GR, IL-6 deprivation via a specific anti-IL-6 antibody (100 ng/ml) significantly decreased GR, as it was noticed, although to a lesser degree, using a specific anti-IL-6 receptor antibody. In Saos-2, cells that express lower concentrations of GR, a 40-hour treatment with human IL-1beta (10 ng/ml) significantly increased both IL-6 production and GR. This latter effect was completely abolished by co-treating the cells with the anti-IL-6 antibody. Our data are consistent with an autocrine up-regulation of GR expression by IL-6 in human osteoblast-like cells. This phenomenon, which is also relevant to paracrine cell-to-cell communication, subserves a feedback loop in the bone microenvironment that restrains excess inducible IL-6 production. In patients having high levels of IL-6 and given GCs, it could offer an additional explanation for the biphasic pattern of bone loss in the course of therapy.

Interleukin-6 upregulates glucocorticoid receptor numbers in human osteoblast-like cells.

Interactions between the endocrine and immune systems are well known with special regard to the hypothalamic-pituitary-adrenal axis. Little of the literature focuses on the complex effects of cytokines on tissue responsiveness to glucocorticoids (GC). In bone tissue, osteoblasts represent a valuable model for studying GC-cytokine interactions. Hence, we have studied two human osteosarcoma cell lines (Saos-2 and MG-63) with different degrees of differentiation and different constitutive IL-6 production (3.4 +/- 0.3 (mean +/- SE) and 3309 +/- 578 pg/10(6) cells). We measured glucocorticoid receptor (GR) number and affinity as a function of the exposure of cells to different amounts of IL-6. Incubation for 20 h with IL-6 at increasing concentrations up to 2000 pg/ml yielded a significant increase of GR binding sites in both cell lines. IL-6 was also able to reverse the inhibitory effect of dexamethasone (1 mumol/l) on GR in both cell lines. In MG-63 cells, expressing higher concentrations of GR, IL-6 deprivation via a specific anti-IL-6 antibody (100 ng/ml) significantly decreased GR. In Saos-2 cells, expressing lower concentrations of GR, a 40 h treatment with human IL-1 beta (10 ng/ml) significantly increased both IL-6 production and GR. This latter effect was completely abolished by co-treating the cells with the anti-IL-6 antibody. Our results provide evidence that IL-6 is an autocrine positive modulator of GR number in human osteoblasts.

Modulation by cytokines of glucocorticoid action.

Glucocorticoids (GC) are potent modulators of the inflammatory response. Their effects serve to down-regulate the inflammatory response and are mediated by genomic pathways that follow the interaction with specific receptors (glucocorticoid receptors, GR). Interleukin (IL)-1, IL-2, and IL-6 are able to increase GC secretion by enhancing synthesis and release of CRH and ACTH. Cytokine effects upon steroidogenesis also occur at the adrenal level. The role of cytokines as modulators of GR has received scarce attention. IL-1 has been shown to up-regulate GR mRNA expression in hypothalamic CRH secreting cells. On the other hand, macrophage migration inhibitory factor (MIF), a T-cell product inducible by inflammatory substances including other cytokines, counterregulates GC action within the immune system. Besides immunocytes and neurons, bone cells are a sensitive target for GC and cytokines. We have found that IL-2 and IL-6 up-regulate remarkably the number of GR binding sites and the expression of GR mRNA in peripheral blood mononuclear cells and in osteoblast-like Saos-2 cells. Available data suggest that inflammatory cytokines have both direct and indirect effects on GC action at the target level. Autocrine-induced transcription of GR in immunocytes and/or osteoblasts could be a mechanism that restrains excess cytokine production.

Study on mutations and antiretroviral therapy (SMART): preliminary results.

Resistance to antiretroviral drugs is believed to be an important cause of treatment failure in human immunodeficiency virus (HIV)-infected patients, however, the role of susceptibility assays in the management of these individuals needs to be defined. SMART (study on mutations and antiretroviral therapy) is an ongoing study on mutations and antiretroviral therapy focused particularly on HIV-infected patients treated with two nucleoside analogue reverse transcriptase inhibitors (NRTIs). Plasma HIV-1 RNA was assessed by NASBA (nucleic acid sequence-based amplifications) (Organon Teknika, Boxtel, The Netherlands) with a detection limit of 80 copies/ml, whereas resistance was assessed by direct sequencing of the RT pol gene in patients with detectable viraemia, and by Antivirogram (Virco) in non-responder patients. The preliminary results of this study show that both genotypic and phenotypic assays identify mutated viral strains in the majority of patients failing a dual regimen. Furthermore, the data indicate a high rate of genotypic resistance to lamivudine in both responders and non-responders, a high rate of phenotypic resistance to lamivudine in non-responders, no genotypic resistance to didanosine and stavudine in responders, and a very low rate of both genotypic and phenotypic resistance to didanosine and stavudine in non-responders.

Interleukin 2 up-regulates glucocorticoid receptor number in human peripheral blood mononuclear cells and the osteosarcoma cell line Saos-2 in vitro.

Glucocorticoids are well-recognized modulators of immunocytes and osteoblasts via specific receptor-mediated mechanisms. We have evaluated the in vitro effect of interleukin 2 (IL-2) on the expression of glucocorticoid receptors (GRs) in peripheral blood mononuclear cells (PBMCs) obtained from healthy donors and osteoblast-like Saos-2 cells. Aliquots of PBMC or Saos-2 cells were incubated for 20 h in the presence or absence of recombinant human IL-2 (100 IU/mL) at 37 degrees C. After incubation, a [3H]dexamethasone radioligand-binding assay and Scatchard analysis were used to determine GR-binding parameters in both cell populations. Saos-2 cells basally express higher numbers of GR than PBMCs. After IL-2, a significant increase in GR number was found for both PBMCs and Saos-2 cells. The relative increase was higher in Saos-2 cells; in PBMCs, the apparent affinity fell to almost half. These data represent an additional piece of evidence that cytokine and steroid hormones may act in a complementary way to regulate specific cell functions.

Varicella-zoster virus (VZV) DNA in cerebrospinal fluid of patients infected with human immunodeficiency virus: VZV disease of the central nervous system or subclinical reactivation of VZV infection?

To identify varicella-zoster virus (VZV) infections of the nervous system in patients infected with human immunodeficiency virus (HIV), polymerase chain reaction (PCR) analysis of cerebrospinal fluid (CSF) samples from 514 consecutive HIV-infected patients with neurological disease was performed to detect VZV DNA. VZV DNA was detected in CSF of 13 (2.5%) of 514 patients. Four of 13 patients had VZV encephalitis or meningoencephalomyelitis. These four patients received intravenous acyclovir therapy; CSF became negative for VZV DNA and clinical conditions improved for two, whereas CSF remained positive for VZV DNA and clinical conditions worsened until death for two. In nine of 13 patients, the neurological symptoms were likely caused by other simultaneous HIV-related complications in the central nervous system. After intravenous therapy with high doses of acyclovir or foscarnet, VZV was cleared from CSF in eight of nine patients. VZV DNA can be detected in CSF of HIV-infected patients in association with either manifestations of neurological VZV disease or subclinical reactivation of VZV infection. Antiviral treatment may be effective in suppressing VZV replication in the nervous system.