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Biomedical subjects

P L Meroni

Publications and source records attributed to P L Meroni.

At least 55 records · Page 3Linked to original sources
PubMed2001

Activation of the immune system and coronary artery disease: the role of anti-endothelial cell antibodies.

On the basis of the role of immuno-mediated inflammation in atherosclerosis we investigated, (1) the prevalence of anti-endothelial cell antibodies (AECA) in ischaemic heart disease (IHD); (2) if beta2-glycoprotein I (beta2-GPI) was the target antigen of AECA; (3) the relationship between AECA, tissue factor (TF) and tissue factor pathway inhibitor (TFPI). In 93 consecutive IHD patients undergoing percutaneous transluminal coronary angioplasty (PTCA) and 105 controls AECA were detected by ELISA on human umbilical vein endothelial cells (HUVEC). AECA positive sera were evaluated for anti-beta2-GPI antibodies by ELISA. TF and TFPI plasma levels were assessed by ELISA. Twelve of 93 (12.9%) IHD patients and only one of 105 controls (0.95%) were AECA positive. The prevalence of AECA was higher in unstable angina (UA) than in effort angina (EA) (P=0.01). Three of 12 AECA positive sera resulted positive for anti-beta2-GPI and showed a marked decrease in EC-binding when tested on HUVEC cultured in serum-free medium. The binding was restored by the addition of beta2-GPI. TF and TFPI levels were similar in AECA positive and AECA negative patients. The rate of angiographically documented clinical recurrences was 66.7% in the AECA positive and 14.8% in the AECA negative group (P=0.0004) with a significant relationship between restenosis and AECA (P<0.0001), unchanged by the inclusion of cardiovascular risk factors in the regression model. Our results suggest a 'role' for AECA in the immune-mediated inflammation in UA beta2-GPI is not the only AECA target antigen. AECA are not responsible for high TF and TFPI levels. The high rate of clinical recurrences after PTCA, confirmed by angiography, in AECA positive patients is in line with such a role and suggests further large-scale 'ad hoc' studies.

Angioplasty, Balloon, Coronary↗
PubMed2001

Risk of congenital complete heart block in newborns of mothers with anti-Ro/SSA antibodies detected by counterimmunoelectrophoresis: a prospective study of 100 women.

OBJECTIVE: To assess the true prevalence of congenital complete heart block (CCHB) in infants of anti-Ro/SSA-positive women known to have connective tissue disease (CTD) and, secondarily, to evaluate the prevalence of other electrocardiographic abnormalities in these newborns at birth. METHODS: A prospective study was conducted in 4 referral hospitals. One hundred anti-Ro/SSAA-positive mothers were followed up before they became pregnant and during the index pregnancy. Counterimmunoelectrophoresis and immunoblotting were used to test for antibodies to extractable nuclear antigens. RESULTS: Of the 100 women with anti-Ro/SSA antibodies, 2 had infants who developed CCHB in utero (2%). The CCHB was detected at 22 weeks and 20 weeks, respectively. One of the 2 mothers had primary Sjögren's syndrome (SS), and the other had undifferentiated CTD (UCTD). No case of CCHB occurred among the infants of 53 mothers with systemic lupus erythematosus (SLE). No fetal death occurred due to CCHB. In 2 centers, electrocardiography was recorded in 24 unselected newborns, and 4 were found to have sinus bradycardia. CONCLUSION: The prevalence of CCHB in newborns of prospectively followed up women already known to be anti-Ro/SSA positive and with known CTD was 2%. This finding is useful with regard to preconception counseling of these women. The risk of delivering an infant with CCHB may be higher in mothers with primary SS or UCTD than in those with SLE. Additional electrocardiographic abnormalities such as sinus bradycardia and prolongation of the QT interval may be present in their children.

Antibodies, Antinuclear↗
PubMed2001

Statins prevent endothelial cell activation induced by antiphospholipid (anti-beta2-glycoprotein I) antibodies: effect on the proadhesive and proinflammatory phenotype.

OBJECTIVE: To investigate the ability of statins, the inhibitors of the hydroxymethylglutaryl-coenzyme A reductase enzyme, to affect endothelial cell activation induced by anti-beta2-glycoprotein I (anti-beta2GPI) antibodies in vitro. METHODS: Human umbilical vein endothelial cell (HUVEC) activation was evaluated as U937 monocyte adhesion, E-selectin, and intercellular adhesion molecule I (ICAM-1) expression by cell enzyme-linked immunosorbent assay and as interleukin-6 (IL-6) messenger RNA (mRNA) expression by RNA protection assay. E-selectin-specific nuclear factor kappaB (NF-kappaB) DNA-binding activity was evaluated by the gel-shift assay. HUVECs were activated by polyclonal affinity-purified IgG, human monoclonal IgM anti-beta2GPI antibodies, human recombinant IL-1beta, tumor necrosis factor alpha, or lipopolysaccharide (LPS). RESULTS: Fluvastatin reduced, in a concentration-dependent manner (1-10 microM), the adhesion of U937 to HUVECs and the expression of E-selectin and ICAM-1 induced by anti-beta2GPI antibodies as well as by cytokines or LPS. Another lipophilic statin, simvastatin, displayed similar effects but to a lesser extent than fluvastatin. The inhibition of E-selectin expression exerted by fluvastatin was related to the impairment of NF-kappaB binding to DNA. Moreover, the drug attenuated the expression of IL-6 mRNA in HUVEC exposed to anti-beta2GPI antibodies or cytokines. Incubation of HUVECs with mevalonate (100 microM), concomitantly with fluvastatin, greatly prevented the inhibitory effect of statin. CONCLUSION: Endothelial activation mediated by anti-beta2GPI antibody can be inhibited by statins. Because of the suggested role of endothelial cell activation in the pathogenesis of antiphospholipid syndrome (APS), our data provide, for the first time, a rationale for using statins as an additional therapeutic tool in APS.

Antibodies, Antiphospholipid↗
PubMed2001

Autoantibodies against nuclear pore complexes are associated with more active and severe liver disease in primary biliary cirrhosis.

BACKGROUND/AIMS: Antibodies against nuclear pore complexes (NPCs) have been detected in primary biliary cirrhosis (PBC), but their clinical relevance is still unsettled. METHODS: We tested sera from 171 consecutive PBC patients and 230 control subjects (149 with autoimmune or viral liver diseases, 28 with systemic lupus erythematosus, and 53 healthy) by immunoblotting for antibodies against purified human NPCs. RESULTS: Antibodies to NPCs were detected in 27% of the patients with PBC, were highly specific (97%), and were not associated with antimitochondrial antibodies. Their prevalence was higher in symptomatic patients (36 vs. 16%, P < 0.01) and was associated (P < 0.001) with more severe disease, as assessed by the presence of cirrhosis or its complications (13% prevalence in patients without cirrhosis, 31% in uncomplicated, and 54% in complicated cirrhosis), or by the application of the Mayo prognostic model (12% in the lowest, 21% in the median, 47% in the highest score tertile). Positive patients had higher levels of serum bilirubin (2.2 +/- 3.7 vs. 1.0 +/- 1.1 mg/dl, P < 0.01) and more marked inflammatory infiltrates on liver biopsy (P < 0.05). CONCLUSIONS: Autoantibodies to NPCs are more prevalent in PBC patients than in controls and are strongly associated with more active and severe disease.

Autoantibodies↗
PubMed2001

Antiphospholipid antibodies and the endothelium.

The interaction between aPL (particularly anti-beta 2GPI antibodies) and endothelium does represent a potential pathogenetic mechanism for the thrombotic manifestations of the syndrome. The autoantibody-mediated EC activation probably plays a role in sustaining the appearance of a proadhesive, proinflammatory, and procoagulant phenotype. The heterogeneity of the APS clinical manifestations is likely linked to the varied effects that aPL can induce on ECs and to the different functions that ECs display depending on the anatomic localization.

Antibodies, Antiphospholipid↗
PubMed2001

Anti-C1q antibodies may help in diagnosing a renal flare in lupus nephritis.

It is still uncertain which, if any, immunologic parameters may help diagnose a renal flare of lupus nephritis. Anti-C1q antibody (Ab) titers have been elevated in patients with lupus with renal involvement, but little information is available on whether the titers are different in quiescent and active phases of lupus nephritis. In this study, we compared anti-C1q Ab titers with other serological test results in 48 patients with biopsy-proven lupus nephritis to assess which parameter could offer the best reliability for differentiating between quiescent and active phases of lupus nephritis. Serum C3 and C4 levels, as well as anti-double-stranded DNA, antiendothelial cell, anti-C1q, and antiphospholipid Ab titers, were evaluated in patients with quiescent renal disease (38 samples) and those with clinical evidence of renal activity (23 samples). Only anti-C1q Ab titers correlated with active renal disease in both univariate (P < 0.0001) and multivariate analysis (P < 0.0001), with a sensitivity of 87% and a specificity of 92%. In six patients, immunologic parameters were measured serially. In all patients, the high anti-C1q Ab titers returned to normal values after treatment-induced remission. The other serological parameters did not show a significant association with renal disease activity. In patients with biopsy-proven lupus nephritis, anti-C1q Ab titers appear to be strongly related to renal disease activity. Their measurement may be useful for confirming the diagnosis of renal flares of lupus nephritis.

Adult↗
PubMed2001

Human monoclonal anti-endothelial cell IgG-derived from a systemic lupus erythematosus patient binds and activates human endothelium in vitro.

Our objectives were to obtain monoclonal anti-endothelial cell antibodies (AECA) from systemic lupus erythematosus (SLE) patients, to characterize their antigen specificity, and their capability to induce a pro-inflammatory and pro-adhesive endothelial phenotype, and to investigate the mechanism of endothelial cell (EC) activation in vitro. Monoclonal IgG AECA were generated by hybridoma formation with human SLE B cells. Antigen specificity was characterized by immunoblotting with enriched cell membrane fractions, by cytofluorimetry and by cell solid-phase ELISA. Endothelial activation was evaluated by measuring increases in U937 cell adhesiveness, adhesion molecule (E-selectin and ICAM-1) expression and IL-6 production. In addition, mechanisms of endothelial activation were investigated by assessment of NF-kappaB by measuring the loss of its inhibitor I-kappaB. mAb E-3 bound live EC and recognized a 42 kDa EC membrane protein, it enhanced U937 adhesiveness, E-selectin and ICAM-1 expression and IL-6 production, and caused the loss of I-kappaB. We conclude this is the first in vitro demonstration that a human monoclonal AECA from a SLE patient reacts with a constitutive endothelial membrane antigen and induces a pro-inflammatory endothelial phenotype through NF-kappaB activation.

Antibodies, Monoclonal↗
PubMed2001

Pathogenic mechanisms mediating antiphospholipid syndrome.

Antiphospholipid antibodies are the marker for antiphospholipid syndrome. There is evidence that these autoantibodies lead to both thrombotic diathesis and obstetrical manifestations. Besides the known interaction with soluble coagulation factors, in vitro and in vivo experimental models and studies in humans recently have shown the ability of antiphospholipid antibodies to modulate functions of cells involved in coagulation homeostasis. These findings support a new hypothesis to explain the paradox of the prolongation of coagulation assays in vitro and the association with thrombophilic diathesis in vivo. Obstetrical manifestations have been linked to a direct antibody effect on the trophoblast leading to defective placentation that is not necessarily associated with thrombotic phenomena. Phospholipid binding proteins such as beta 2 -glycoprotein I appear to behave as a bridge between circulating antiphospholipid antibodies and cellular targets.

Animals↗
PubMed2001

Idiopathic pulmonary hemosiderosis in an adult. Favourable response to azathioprine.

Idiopathic pulmonary hemosiderosis (IPH) is a rare disorder characterised by intermittent, diffuse alveolar hemorrhage (DAH). Although an inflammatory pulmonary capillaritis can be evidenced in most patients with DAH, IPH is a distinct entity in which pulmonary inflammatory alterations are lacking. Most cases occur in children, although the disease has been exceptionally reported in adults too. Here, we, describe a case of IPH in a 30-year-old woman who was admitted to our hospital because of recurrent episodes of hemoptysis since the age of 21. IPH was diagnosed on the basis of: 1) an open lung biopsy showing focal alveolar edema and hemorrhage without parenchymal inflammatory alterations, 2) a bronchoalveolar lavage showing hemosiderin-laden macrophages, and 3) exclusion of infectious or immunologic causes of hemoptysis. Prednisone administration could control the disease, but every attempt to lower the dose to less than 25 mg per day was followed by recurrence of hemoptysis. Then, azathioprine was started, and after three months prednisone was gradually tapered to the dose of 10 mg per day, without any relapse of the disease. These findings indicate that azathioprine, in combination with prednisone, may be an effective therapy for IPH and suggest that an immunologic mechanism could be involved in the pulmonary capillary damage underlying alveolar bleeding.

Adult↗
PubMed2000

Anti-endothelial cell antibodies in patients with coronary atherosclerosis.

Anti-endothelial cell antibodies (AECA) have been shown to possess endothelial cell activation properties and to harbor pathogenic potential in experimental animal models of autoimmune systemic disorders. Atherosclerosis is a form of an inflammatory condition in which the immune system has been shown to be involved. The aim of the present study was to assess the presence of AECA in patients with coronary atherosclerosis. A total of 134 patients admitted for chest pain of suspected anginal origin were evaluated for coronary artery atherosclerosis by angiography. Sera were drawn prior to the procedure for the determination of AECA employing cyto-ELISA. AECA positive sera were further evaluated for its ability to promote in vitro E-selectin expression by HUVEC using a cell-based ELISA. Patients with no coronary artery involvement had levels of AECA that did not differ from those obtained for patients with confirmed coronary atherosclerosis (one, two or three vessel disease). Furthermore, AECA positive sera from patients, with or without coronary atherosclerosis displayed similar capacity of inducing E-selectin expression by endothelial cells. AECA may not stand as an optimal mean of discriminating atherosclerotic from non-atherosclerotic patients. The ability of AECA to activate endothelial cells is also not unique to patients with atherosclerosis and is evident also in age-matched control subjects.

Aged↗
PubMed2000

Antiphospholipid antibodies affect trophoblast gonadotropin secretion and invasiveness by binding directly and through adhered beta2-glycoprotein I.

OBJECTIVE: To investigate the in vitro ability of antiphospholipid antibodies (aPL) to bind human trophoblast cells and to affect gonadotropin secretion and invasiveness. METHODS: Antiphospholipid antibody IgG from women with recurrent miscarriages, beta2-glycoprotein I (beta2GPI)-independent IgG aPL human monoclonal antibody (mAb) (519), and IgM anti-beta2GPI human mAb (TMIG2) were investigated for their binding to trophoblasts cultured for various amounts of time, their ability to affect invasiveness of Matrigel-coated filters, and their release of human chorionic gonadotropin (hCG). RESULTS: Polyclonal IgG aPL, as well as mAb 519 and TMIG2, bound to trophoblasts, the highest binding being found when cells displayed the greatest amount of syncytium formation. TM1G2 binding was found to be betaGPI dependent. Both polyclonal and monoclonal aPL, but not the controls, significantly reduced hCG release and Matrigel invasiveness. CONCLUSION: These findings suggest that aPL recognition of both anionic PL and adhered beta2GPI on trophoblast cell structures might represent a potential pathogenetic mechanism for defective placentation in women with the antiphospholipid syndrome.

Anions↗
PubMed2000

QT interval prolongation in asymptomatic anti-SSA/Ro-positive infants without congenital heart block.

OBJECTIVE: To analyze the electrocardiograms (EKGs) of infants born to mothers with anti-SSA/Ro antibodies in order to evaluate the QT interval (the time from the beginning of the QRS complex to the end of the T wave). METHODS: Sera from mothers and children were analyzed for anti-Ro and anti-SSB/La antibodies by enzyme-linked immunosorbent assay (ELISA) and by Western blot analysis. Fine specificity of anti-Ro antibodies was evaluated by solid-phase ELISA against recombinant 52- and 60-kd proteins and by Western blot. A retrospective chart review was conducted for EKG analysis. Twenty-eight EKG tracings (21 from anti-Ro-positive and 7 from anti-Ro-negative infants born to mothers with autoimmune diseases) were analyzed by a single investigator who was blinded to the infant's antibody status. The QT interval was measured and corrected for heart rate according to Bazett's formula. RESULTS: The mean QT interval was significantly longer in anti-Ro-positive than in anti-Ro-negative infants, also after correction for heart rate (QTc) (P = 0.001). Nine of 21 anti-Ro-positive infants and 0 of 7 anti-Ro-negative infants had QTc values above the upper normal limit (440 msec). A 24-hour EKG recording was performed on 5 patients and confirmed the QT prolongation. These infants were subsequently treated with a beta-blocker in order to prevent arrhythmias. CONCLUSION: Infants born to mothers who carry anti-Ro autoantibodies may show QT interval prolongation and should be monitored with EKG during the first months of life.

Adult↗
PubMed2000

Interaction between chronically HIV-infected promonocytic cells and human umbilical vein endothelial cells: role of proinflammatory cytokines and chemokines in viral expression modulation.

HIV type 1 expression was significantly up-regulated in chronically infected promonocytic cell line (U1) co-cultured with human umbilical vein endothelial cells (HUVEC). Virus replication, evaluated as supernatant p24 release, was higher when U1 were co-cultured with IL-1beta-activated HUVEC than with unstimulated HUVEC. When non-adherent U1 were removed from co-cultures, the remaining U1 cells adherent to the endothelial monolayer still showed enhanced HIV replication in comparison with an equal number of U1 cultured alone. While addition of adhesion molecule blocking antibodies (anti-intercellular adhesion molecule-1 (ICAM-1), -vascular cell adhesion molecule-1 (VCAM-1), -CD18 and -very late antigen-4 (VLA-4)) strongly inhibited adherence of U1 cells to endothelial monolayers, such treatment resulted in only a partial reduction in p24 release. Furthermore, HIV replication in U1 cells was enhanced on culture in HUVEC-conditioned media. Such data suggest that soluble mediators secreted by endothelial monolayers may modulate HIV-1 expression. Indeed, addition of cytokine and chemokine antagonists to both U1/HUVEC co-cultures and to U1 cultured in HUVEC-conditioned media clearly down-regulated p24 release. Anti-IL-6, anti-tumour necrosis factor-alpha (TNF-alpha) and, particularly, anti-MCP-1 MoAbs reduced p24 release, while anti-IL-8 polyclonal antiserum and IL-1 receptor antagonist (IL-1Ra) had no significant effect. Thus, the interaction between HUVEC and infected monocytic cells up-regulates HIV-1 replication predominantly through production of endothelium-derived soluble factors including MCP-1, TNF-alpha and IL-6. This phenomenon may influence the passage of HIV-1 from latency to productive replication and enhance virus spreading during physiological and/or pathological contact of monocytes with endothelium.

Cell Line↗