AB0153 ADIPOSE-DERIVED STROMAL/STEM CELLS FROM SYSTEMIC SCLEROSIS PATIENTS SUCCESSFULLY EXERT A PARACRINE ANTI-FIBROTIC ACTIVITY AND INDUCE A PRO-ANGIOGENIC PHENOTYPE OF SCLERODERMA FIBROBLASTS IN VITRO

Background:

Adipose-derived stromal/stem cells (ADSCs) are multipotential non-hematopoietic progenitor cells with anti-inflammatory, immunomodulatory and regenerative effects. They have the advantage of accessibility and potent pro-angiogenic effects when compared with other stem cells, such as bone-marrow derived stem cells. Recent studies have shown that autologous fat grafting may be effective in the treatment of fibrotic and vascular complications in systemic sclerosis (SSc), despite a pro-fibrotic signature.

Objectives:

Aim of the study was to better characterize the proliferative and secretive profile of ADSCs in normoxic and hypoxic conditions, and to evaluate the mechanisms by which ADSCs exert these observed clinical effects.

Methods:

Adipose tissue samples were obtained by liposuction from 12 SSc patients and 10 healthy donors (HD). ADSCs were purified according to their adherence to the plastic and characterized to express specific MSC surface antigens by flow cytometry analysis. Proliferation of ADSCs from SSc patients and normal controls was evaluated in normoxic and hypoxic conditions. Fibroblasts and ADSCs derived from SSc patients were co-cultured in direct and indirect culture systems and compared to HD. Fibroblasts proliferation, mRNA expression and protein secretion of VEGF and known fibrotic mediators including TGF β-1, TGFR, CTGF, Collagen type I (Col I) were analyzed in the same conditions.

Results:

Normoxic and hypoxic culture conditions did not modify the proliferation rate of both normal and SSc ADSCs. Hypoxia significantly increased mRNA expression of VEGF by HD and SSc ADSCs but had no effect on the mRNA expression of pro-fibrotic mediators, ie TGFβ and TGFR. Normal and SSc fibroblast proliferation was significantly reduced in both co-culture systems (p < 0.001) and by treatment with normoxic and hypoxic conditioned medium (CM) (p=0.001 and p=0.002). In the same conditions, mRNA expression and protein secretion of TGF-β1, CTGF and Col I were significantly reduced (p = 0.003, p =0.02, p=0.04). These results were confirmed when normal and SSc fibroblasts were cultured in the presence of ADSCs normoxic and hypoxic CM (p=0.02 and p=0.01). Furthermore, a significant increase in mRNA expression and production of VEGF was observed in SSc fibroblasts cultured in the presence of normoxic and hypoxic CM (p = 0.002 and p< 0.0001, respectively).

Conclusion:

We found that treatment with the medium from normoxic and hypoxic preconditioned ADSCs has an anti-fibrotic effect through both the inhibition of fibroblast proliferation and key mediators of fibrosis. The increased expression of VEGF by SSc fibroblasts in the presence of normoxic and, even more, hypoxic ADSCs CM, suggests that ADSCs can induce a paracrine pro-angiogenic phenotype, even in fibroblasts with a pro-fibrotic signature. Altogether these data show that ADSCs may exert their anti-fibrotic and pro-angiogenetic effects on SSc fibroblasts by the secretion of paracrine factors, partly explaining the mechanisms underlining beneficial clinical results of fat graft in SSc patients.

Disclosure of Interests:

Nicoletta Del Papa: None declared, Maurizio Lorini: None declared, Vincenzo Carbonelli: None declared, Antonina Minniti: None declared, Francesca Pignataro: None declared, Wanda Maglione: None declared, Gabriele Di Luca: None declared, Nicola Montano: None declared, Roberto Caporali Consultant of: AbbVie; Gilead Sciences, Inc.; Lilly; Merck Sharp & Dohme; Celgene; Bristol-Myers Squibb; Pfizer; UCB, Speakers bureau: Abbvie; Bristol-Myers Squibb; Celgene; Lilly; Gilead Sciences, Inc; MSD; Pfizer; Roche; UCB

AB0125 EXPRESSION OF INTERFERON TYPE I- AND TYPE II-INDUCED GENES IN PATIENTS WITH SJÖGREN’S SYNDROME WITH AND WITHOUT EXTRAGLANDULAR INVOLVEMENT

Background:

It is well known that Sjögren’s syndrome (SjS) is characterized by an upregulation of interferon (IFN)-induced genes. Namely, IFN type I signature has been reported in peripheral blood mononuclear cells (PBMCs) and in salivary glands of patients with this disease. However, few data are available on possible variability of IFN-induced gene upregulation in different clinical phenotypes of SjS.

Objectives:

To verify whether upregulation of IFN-induced genes is comparable in patients with SjS characterized by different clinical phenotypes, i.e., patients with systemic extraglandular manifestations (EGMs) versus patients with a disease limited to glandular features (GFs) and with widespread pain (WP).

Methods:

The study population was composed by 11 patients with SjS and EGMs (1 male, age range 18-78 years), and 10 patients with only GFs and WP (all females, age range 46-81 years), all classified according to ACR-EULAR criteria. The prevalence of anti-SSA(Ro) antibodies was 11/11 and 8/10, respectively. Lip biopsy was positive in all cases. Six healthy normal subjects were also included in the study as control population.

Four IFN type I- and 5 IFN type II-induced genes were chosen for the study on the basis of previous literature data. Total RNA from each patient and control was isolated from purified PBMCs, followed by cDNA preparation and real time quantitative-PCR (RQ-PCR) analysis, using specific primer/probe sets. For calculation of relative expression, all samples were normalised against expression of a household gene (beta actin). A further normalization was performed against the mean value of relative expression obtained in the normal controls. Final fold change values were determined from the double-normalised values using the 2−ΔΔCT method (Applied Biosystems).

Results:

Fold change values of gene expression of both IFN type I- and type II-induced genes in PBMCs were different in the two clinical phenotypes of SjS. Fold change values of IFN type I-induced genes appeared strongly higher in patients with EGM, and some of them only moderately increased in those with only GF and WP. The expression of some of IFN type II-induced genes were slightly increased in patients belonging to both clinical phenotypes. Results are detailed in the table.

Table.

Fold change values of gene expression in patients with SjS plus EGMs, in patients with disease limited to GF and WP, and in controls.

GeneMX1IFIT1IFT3IFI44IDO1GRP1MIGIP-10P2RY14SjS-EGMs85.938.524.440.425.18.34.51.55.5SJS-GF-WP4.21.72.04.84.11.20.60.31.3Controls2.11.61.11.51.41.31.51.31.4

Legend. IFN type I-induced genes: MIX, IFN-induced GTP binding protein 1; IFIT1, IFN-induced protein with tetratricopeptide repeats 1; IFIT3, IFN-induced protein with tetratricopeptide repeats 3; IFI44, IFN-induced protein 44.

IFN type II-induced genes: IDO1, indolamine-deoxygenase 1; GBP1, guanylate binding protein 1; MIG, C-X-C chemokine 9 (CXCL9); IP-10, C-X-C chemokine 10 (CXCL10); P2RY14, purinergic receptor 14.

Conclusion:

The present data indicate that IFN type I- and, to a lesser degree, type II-induced genes are upregulated in patients with SjS, but this phenomenon is consistently stronger in patients with systemic EGMs. In patients with only GFs IFN-induced gene upregulation is milder in PBMCs, and then probably more restricted to the exocrine target tissues.

Disclosure of Interests:

Nicoletta Del Papa: None declared, Claudio Vitali: None declared, Maurizio Lorini: None declared, Vincenzo Carbonelli: None declared, Wanda Maglione: None declared, Francesca Pignataro: None declared, Antonina Minniti: None declared, Nicola Montano: None declared, Roberto Caporali Consultant of: AbbVie; Gilead Sciences, Inc.; Lilly; Merck Sharp & Dohme; Celgene; Bristol-Myers Squibb; Pfizer; UCB, Speakers bureau: Abbvie; Bristol-Myers Squibb; Celgene; Lilly; Gilead Sciences, Inc; MSD; Pfizer; Roche; UCB

Co-occurrence of IgE and IgG autoantibodies in patients with chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU) pathogenesis shows a complex and still unclear interplay between immunoglobulin (Ig)G- and IgE-mediated autoimmunity, leading to mast cell and basophil degranulation and wheal formation. The objective of this study was to evaluate at the same time IgE- and IgG-reactivity to well recognized and recently reported autoantigens in CSU patients, and to assess the effects of such reactivity on response to the anti-IgE monoclonal antibody omalizumab. Twenty CSU patients underwent omalizumab treatment. Urticaria activity score 7 (UAS7) was recorded at baseline and at different drug administration time-points for categorizing early-, late- or non-responders. At baseline, sera from the 20 patients and from 20 controls were tested for IgE and IgG autoantibodies to high- and low-affinity IgE receptors (FcεRI and FcεRII), tissue factor (TF) and thyroglobulin (TG) by immunoenzymatic methods. Antibody levels were compared with those of controls and analysed according to response. Eighteen patients were omalizumab responders (11 early and seven late), while two were non-responders. More than 50% of patients had contemporary IgE and IgG to at least to one of the four different autoantigens. Late responders showed higher levels of both anti-TF IgE and IgG than early responders (P = 0·011 and P = 0·035, respectively). Twenty-five per cent of patients had levels of anti-FcεRI IgE, exceeding the upper normal limit, suggesting that it could be a novel auto-allergen in CSU. In CSU, there is an autoimmune milieu characterized by the co-existence of IgE and IgG autoantibodies to the same antigen/allergen, particularly in late responders to omalizumab, possibly explaining the slower response.

Oxidative Stress and Low-Grade Inflammatory Status as Cardiometabolic Risk Factors in Italian Occupational Overweight/Obese Subjects

Obesity is associated with increased risk of cardiometabolic diseases. Adipocytokines (e.g. leptin), produced by the endocrine function of adipose tissue, can contribute to cardiometabolic risk in overweight and obese people. Oxidative stress, imbalance between oxidants and antioxidants, is considered a cardiovascular risk factor. High serum oxidized LDL (oxLDL) levels, marker of lipid peroxidation, a primary cause of atherosclerosis, can contribute to its progression. The aims of this study are to assess markers of oxidative status and cytokine profile and evaluate their role as cardiometabolic risk factors and possible correlations. In this cross-sectional study, we enrolled 76 occupational overweight-obese adults (46 females, 30 males; aged 46.8±9.5; BMI 33.7±4.8 kg/m2) without any previous cardiovascular disease. Oxidative status was measured by evaluating serum Reactive Oxygen Species (ROS) levels, Total Antioxidant Capacity (TAC) and oxLDL concentrations. All subjects' soluble cytokine and adhesion molecule levels were evaluated by cytofluorimetric method and compared with 35 controls matched for sex and age. ROS and oxLDL levels were high in 84% and 92% of the study population, respectively, despite adequate TAC (68%). Female ROS levels were significantly higher than those of males (414±99.3 vs 318±48.2 UCarr, p<0.0001), while their oxLDL levels were lower (95.3±22 vs 105.2±19.4 U/L, p=0.1). Leptin and sICAM-1 (intracellular adhesion molecule involved in leukocyte migration to inflamed area) levels of the study population were significantly higher than those of controls (93.8±89.1 vs 25.3±23 ng/mL, p=0.0002 and 505.8±236.7 vs 339.2±119.6 ng/mL, p=0.0009, respectively). Overweight/obese occupational subjects showed oxidative stress conditions accompanied by low chronic inflammatory status, possibly contributing to increased cardiometabolic risk.

Interleukin-10 down-regulates oxidative metabolism and antibody-dependent cellular cytotoxicity of human neutrophils

The authors investigated the ability of interleukin-10 (IL-10) to modulate some constitutive or interferon-gamma (IFN-gamma)-enhanced activities of human neutrophils. An 18h culture of neutrophils with IL-10 dose-dependently down-regulated their capacity to produce O(2)- and lucigenin-amplified chemiluminescence in response to n-formyl-methionyl-leucylphenyl-alanine (FMLP). Furthermore, treatment of neutrophils with IL-10 decreased in a dose-dependent fashion, their capacity to lyse antibody-coated sheep erythrocytes. Membrane expression of Fc gamma RI, Fc gamma RII, Fc gamma RIII, CR1, CR3 and Fc gamma R- and CR-mediated phagocytosis were not modified by the cytokine. Culture of neutrophils with IFN-gamma (100 U/ml) did not modify their Fc gamma R- and CR-mediated phagocytosis, but significantly up-regulated Fc gamma RI and CR3 membrane expression as well as their oxidative metabolism and antibody-dependent cellular cytotoxicity (ADCC). When IL-10 and IFN-gamma were added simultaneously to neutrophil culture, IL-10 dose-dependently reduced IFN-gamma-induced increase of CR3 expression, O(2)- production (in response to both FMLP and phorbol 12-myristate 13-acetate, or PMA) and ADCC, but did not change Fc gamma RI expression on phagocytes. These results demonstrate that IL-10 is a significant neutrophil deactivator and provide new information on the role of IL-10 in the regulation of neutrophil-mediated inflammatory processes.

IL-10 up-regulates human monocyte phagocytosis in the presence of IL-4 and IFN-gamma

Interleukin-10 (IL-10), a cytokine produced by type 2 helper T (Th2) cells, inhibits the microbicidal effector function of interferon-gamma (IFN-gamma)-activated macrophages. However, recent observations indicate that IL-10, like IFN-gamma, increases Fc gamma RI expression and Fc gamma R-mediated cytotoxic activity on human monocytes, suggesting that this cytokine cannot be classified purely as a monocyte deactivator. The present study found that incubation for 40 h of human monocytes or monocyte-derived macrophages in the presence of IL-10 caused a significant enhancement of their capacity to ingest particles coated with immunoglobulin G (Fc gamma R-mediated ingestion) or with C3b/C3bi fragments of the complement system (CR1/CR3-mediated ingestion). The number of phagocytosing cells (% phagocytosis) and the number of ingested particles per cell (phagocytic index) were both significantly higher after 40-h incubation of monocytes with IL-10 concentrations > or = 1 U/ml. This up-regulating activity on phagocytosis was completely reversed by anti-IL-10 monoclonal antibody (mAb). As previously reported, IL-10 stimulated Fc gamma RI expression on monocytes but did not induce the expression of Fc gamma RII, Fc gamma RIII, CR1, and CR3. IFN-gamma, like IL-10, up-regulated only Fc gamma RI expression but significantly reduced both Fc gamma R- and CR-mediated ingestion. IL-10 almost completely reversed the IFN-gamma-induced inhibition of both Fc gamma R- and CR-mediated phagocytosis, without concomitant changes in membrane expression of phagocytic receptors. Exposure of monocytes to IL-4 reduced the membrane expression of all three Fc gamma Rs and also inhibited Fc gamma R-mediated ingestion. On the other hand, IL-4 up-regulated both CR3 expression and CR-mediated ingestion on cultured monocytes. IL-10 not only neutralized the down-regulatory effect of IL-4 on Fc gamma R expression but also completely reversed the IL-4-induced suppression of Fc gamma R-mediated phagocytosis. Exposure of monocytes to a combination of IL-10 and IL-4 resulted in a synergistic effect on CR-mediated ingestion, even though no additive effects were observed on CR membrane expression. Finally, culture of monocytes in medium containing anti-IL-10 mAb significantly reduced their capacity to ingest IgG- or C3b/C3bi-coated particles, suggesting a role for endogenously produced IL-10 in the modulation of phagocytosis by human monocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

Abnormal neutrophil chemotaxis in bone marrow transplant patients correlates with impaired 31D8 monoclonal antibody binding

BACKGROUND

31D8 monoclonal antibody (mAb) has been shown to bind heterogeneously to human neutrophils, identifying subsets of cells which differ in their functional response to chemotactic stimuli. In this study we used 31D8 mAb to determine whether differences in neutrophil subpopulations might explain the long-lasting decreased chemotaxis observed in bone marrow transplant recipients.

METHODS

Thirty patients with self-sustaining hematopoiesis 1 to 5 years bone marrow transplantation (BMT) (15 allogeneic and 15 autologous) performed for acute lymphocytic leukemia (ALL, 10 patients) or acute myelogenous leukemia in complete remission (8 patients), Hodgkin's lymphoma (2 patients), chronic myeloid leukemia (8 patients) and severe aplastic anemia (2 patients) were included in the study. Neutrophil chemotaxis was evaluated using a modified Boyden chamber assay and 31D8 binding was determined by indirect immunofluorescence and cytofluorimetric analysis.

RESULTS

Neutrophil chemotaxis was significantly impaired in the BMT group with respect to controls. The chemotactic defect strikingly correlated with autologous BMT and, in particular, with ALL as the pre-existing disease. No differences between patients and controls were observed in the percentage of 31D8 bright and dull neutrophils. However, when mean fluorescence intensity (MFI) was analyzed as a relative measure of 31D8 antigen expression on the overall neutrophil population, a significant decrease was observed in neutrophils from BMT patients with respect to controls. As for chemotaxis, the impairment of 31D8 binding was more evident in autologous BMT and strikingly correlated with ALL as the pre-existing disease regardless of age, sex and time since BMT. Moreover, a significant positive correlation between impaired chemotaxis and decreased 31D8 binding was found in our patients.

CONCLUSIONS

These findings suggest that the decreased neutrophil chemotaxis observed in some BMT patients may be due in part to circulating 31D8 dull neutrophils, although the causes for the decreased 31D8 binding and for the quite pronounced neutrophil defect in ALL patients remain unknown.

Fc receptors expression and function in mononuclear phagocytes from AIDS patients: modulation by IFN-gamma

Fc-receptor (FcR)-mediated phagocytosis and FcR (FcRI, FcRII and FcRIII) membrane expression was studied on freshly separated and cultured monocytes (Mo) from 20 AIDS patients and 20 healthy controls. Both Mo and Mo-derived macrophages from AIDS patients presented a significant defect in their capacity to ingest IgG-coated erythrocytes (EA) compared to control cells. This functional defect did not depend on a decline in the number of FcR+ cells or on a decrease in the expression of FcR on their surface. In fact, the percentages of phagocytes reacting with anti-FcRI MoAb (32.2) or anti-FcRII MoAb (IV.3) were similar for controls and AIDS patients, while the percentage of FcRIII-positive Mo (MoAb 3G8) was higher in the AIDS population than in controls, though this difference was not seen on cultured Mo. The level of FcRI expression, evaluated as mean fluorescence intensity (MFI), was higher on freshly separated Mo from AIDS patients than from controls but this difference disappeared also with differentiation of Mo to Mo-derived macrophages in vitro. Parallel analysis of FcRII and FcRIII on phagocytes revealed no differences in the MFI between the AIDS and control groups. Some observations suggested that this functional defect might be secondary to phagocyte priming by circulating IFN-gamma: (1) in vitro stimulation of Mo with hrIFN-gamma, which increased FcRI expression, actually reduced phagocytosis of IgG-coated particles; and (2) IFN-gamma concentrations were increased in AIDS patients' plasma. In spite of these findings, no significant correlation was found between plasma IFN-gamma concentrations and FcR-mediated ingestion in AIDS patients, making the hypothesis uncertain. Even if the basis for the impaired FcR-mediated phagocytosis in AIDS patients remains unclear, this functional defect may have a role in the immunopathogenesis of AIDS, constituting a component cause of the immunodeficiency.