PubMed Health⌕ Search

Biomedical subjects

G Martino

Publications and source records attributed to G Martino.

At least 19 recordsLinked to original sources
PubMed1999

Caspase-1 regulates the inflammatory process leading to autoimmune demyelination.

T cell-mediated inflammation is considered to play a key role in the pathogenic mechanisms sustaining multiple sclerosis (MS). Caspase-1, formerly designated IL-1beta-converting enzyme, is crucially involved in immune-mediated inflammation because of its pivotal role in regulating the cellular export of IL-1beta and IL-18. We studied the role of caspase-1 in experimental autoimmune encephalomyelitis (EAE), the animal model for MS. Caspase-1 is transcriptionally induced during EAE, and its levels correlate with the clinical course and transcription rate of proinflammatory cytokines such as TNF-alpha, IL-1beta, IFN-gamma, and IL-6. A reduction of EAE incidence and severity is observed in caspase-1-deficient mice, depending on the immunogenicity and on the amount of the encephalitogenic myelin oligodendrocyte glycoprotein (MOG) peptide used. In caspase-1-deficient mice, reduced EAE incidence correlates with defective development of anti-MOG IFN-gamma-producing Th1 cells. Finally, pharmacological blockade of caspase-1 in Biozzi AB/H mice, immunized with spinal cord homogenate or MOG35-55 peptide, by the caspase-1-inhibitor Z-Val-Ala-dl -Asp-fluoromethylketone, significantly reduces EAE incidence in a preventive but not in a therapeutic protocol. These results indicate that caspase-1 plays an important role in the early stage of the immune-mediated inflammatory process leading to EAE, thus representing a possible therapeutic target in the acute phase of relapsing remitting MS.

Amino Acid Chloromethyl Ketones↗
PubMed1999

Relevance of interleukin 1 receptor antagonist intron 2 polymorphism in Italian MS patients.

The A1/A1 genotype of the anti-inflammatory cytokine interleukin 1 receptor antagonist (IL-1Ra) polymorphism was more frequent in 339 Italian MS patients than in healthy controls (HCs) (odds ratio = 1.83). A more aggressive disease course was also associated with A1+ genotypes and might reflect the reduced ability of mononuclear cell cultures of A1+ HCs to produce IL-1Ra. We conclude that an IL-1Ra gene polymorphism is associated with occurrence of disease and clinical course variability in Italian MS patients.

Adult↗
PubMed1999

Immunopathogenesis of multiple sclerosis: the role of T cells.

Multiple sclerosis is considered to be an autoimmune disease that results from aberrant immune responses to central nervous system antigens. T cells are considered to be crucial in orchestrating an immunopathological cascade that culminates in damage to the myelin sheath, oligodendrocytes and axons.

Humans↗
PubMed1999

Effector pathways in immune mediated central nervous system demyelination.

Multiple sclerosis is generally regarded to be a primarily T-cell driven disease. Recent evidence has refocused interest on antibodies. Adhesion molecules, matrix metalloproteinases, chemokines and cytokines, and nitric oxide and oxygen metabolites all participate in the amplification and effector stages of the disease.

Animals↗
PubMed1999

TE671 cell-based ELISA for anti-acetylcholine receptor antibody determination in myasthenia gravis.

BACKGROUND: Acetylcholine receptor (AChR) from human muscles is the antigen used currently in radioimmunoprecipitation assays (RIPAs) for the determination of anti-AChR antibodies in the diagnosis of myasthenia gravis (MG). Our aim was to develop and validate an ELISA using TE671 cells as the source of AChR. METHODS: After TE671 cell homogenization, the crude AChR extract was used for plate coating. Anti-AChR antibodies were determined in 207 MG patients and in 77 controls. RESULTS: The mean intra- and interassay CVs (for two samples with different anti-AChR antibody concentrations) were 9.7% and 15.7%, respectively. Test sensitivity and specificity, for generalized MG, were 79.5% (95% confidence interval, 72.8-85.0%) and 96.1% (89.0-99.1%). The detection limit was 2 nmol/L. Anti-AChR antibody concentrations from 53 MG patients, as tested with our ELISA, showed good agreement with an RIPA with a mean difference (SD) of 1.0 (5.6) nmol/L. CONCLUSION: Our ELISA is a simple screening test for the diagnosis of MG and enables rapid and inexpensive patient follow-up.

Adolescent↗
PubMed1999

Tumor necrosis factor-alpha and its soluble receptors in plasma and cerebrospinal fluid of multiple sclerosis patients treated with methylprednisolone.

Demyelination is the main pathological feature of multiple sclerosis (MS), a chronic inflammatory disease of the central nervous system. Tumor necrosis factor-alpha (TNF-alpha) can cause myelin damage and contribute to MS pathogenesis. We measured plasma and cerebrospinal fluid (CSF) levels of TNF-alpha and its soluble receptors, TNF-sRp55 and TNF-sRp75, in 18 patients with active MS, and in neurological and healthy controls. The same determinations were repeated on plasma and on CSF samples that were collected after the MS patients had ended a six-day treatment with high-dose methylprednisolone (MP). Pre- and post-treatment plasma and CSF TNF-alpha levels, when detectable, and those of TNF-sRp75, did not vary, and were similar to those of controls. CSF TNF-sRp55 levels were higher in acute MS patients than in controls. Post-treatment CSF TNF-sRp55 levels were higher than in the active phase of the disease. The MS patients, who clinically improved, tended to have the highest CSF TNF-sRp55 levels. The increase was due to intrathecal TNF-sRp55 synthesis. Although it is involved in MS pathogenesis, TNF-alpha is not detectable in plasma or in CSF samples from MS patients in various phases of the disease. A better marker of disease activity seems to be CSF TNF-sRp55 levels. The increased CSF levels of TNF-sRp55 in response to MP circumstantially suggest that this receptor could partially account for the beneficial effects of MP in acute MS.

Adult↗
PubMed1998

Central nervous system delivery of interleukin 4 by a nonreplicative herpes simplex type 1 viral vector ameliorates autoimmune demyelination.

Multiple sclerosis (MS) is a T cell-mediated organ-specific inflammatory disease leading to central nervous system (CNS) demyelination. On the basis of results obtained in experimental autoimmune encephalomyelitis (EAE) models, MS treatment by administration of antiinflammatory cytokines such as interleukin 4 (IL-4) is promising but is hampered by the limited access of the cytokines to the CNS and by the pleiotropic effects of systemically administered cytokines. We established a cytokine delivery system within the CNS using non-replicative herpes simplex type 1 (HSV-1) viral vectors engineered with cytokine genes. These vectors injected into the cisterna magna (i.c.) of mice diffuse in all ventricular and subarachnoid spaces and infect with high efficiency the ependymal and leptomeningeal cell layers surrounding these areas, without obvious toxic effects. Heterologous genes contained in the vectors are efficiently transcribed in infected ependymal cells, leading to the production of high amounts of the coded proteins. For example, 4.5 ng of interferon gamma (IFN-gamma) per milliliter is secreted into the cerebrospinal fluid (CSF) up to day 28 postinjection (p.i.) and reaches the CNS parenchyma in bioactive form, as demonstrated by upregulation of MHC class I expression on CNS-resident cells. We then exploited the therapeutic potential of the vectors in EAE mice. An HSV-1-derived vector containing the IL-4 gene was injected i.c. in Biozzi AB/H mice at the time of EAE induction. We found the following in treated mice: (1) delayed EAE onset, (2) a significant decrease in clinical score, (3) a significant decrease in perivascular inflammatory infiltrates and in the number of macrophages infiltrating the CNS parenchyma and the submeningeal spaces, and (4) a reduction in demyelinated areas and axonal loss. Peripheral T cells from IL-4-treated mice were not affected either in their antigen-specific proliferative response or in cytokine secretion pattern. Our results indicate that CNS cytokine delivery with HSV-1 vectors is feasible and might represent an approach for the treatment of demyelinating diseases. Advantages of this approach over systemic cytokine administration are the high cytokine level reached in the CNS, the absence of effects on the peripheral immune system, and the long-lasting cytokine production in the CNS after a single vector administration.

Animals↗
PubMed1998

IL-12 is involved in the induction of experimental autoimmune myasthenia gravis, an antibody-mediated disease.

IL-12 has been shown to be involved in the pathogenesis of Th1-mediated autoimmune diseases, but its role in antibody-mediated autoimmune pathologies is still unclear. We investigated the effects of exogenous and endogenous IL-12 in experimental autoimmune myasthenia gravis (EAMG). EAMG is an animal model for myasthenia gravis, a T cell-dependent, autoantibody-mediated disorder of neuromuscular transmission caused by antibodies to the muscle nicotinic acetylcholine receptor (AChR). Administration of IL-12 with Torpedo AChR (ToAChR) to C57BL/6 (B6) mice resulted in increased ToAChR-specific IFN-gamma production and increased anti-ToAChR IgG2a serum antibodies compared with B6 mice primed with ToAChR alone. These changes were associated with earlier and greater neurophysiological evidence of EAMG in the IL-12-treated mice, and reduced numbers of AChR. By contrast, when IL-12-deficient mice were immunized with ToAChR, ToAChR-specific Th1 cells and anti-ToAChR IgG2a serum antibodies were reduced compared to ToAChR-primed normal B6 mice, and the IL-12-deficient mice showed almost no neurophysiological evidence of EAMG and less reduction in AChR. These results indicate an important role of IL-12 in the induction of an antibody-mediated autoimmune disease, suggest that Th1-dependent complement-fixing IgG2a anti-AChR antibodies are involved in the pathogenesis of EAMG, and help to account for the lack of correlation between anti-AChR levels and clinical disease seen in many earlier studies.

Animals↗
PubMed1998

Proinflammatory cytokines regulate antigen-independent T-cell activation by two separate calcium-signaling pathways in multiple sclerosis patients.

Central nervous system (CNS) lesions typical of multiple sclerosis (MS) are characterized by demyelinating inflammatory infiltrates that contain few CNS antigen-specific autoreactive T cells and a multitude of pathogenic non-antigen-specific mononuclear cells. Here, we report that in patients with MS the combined action of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNFalpha), interleukin (IL)-2, and IL-6 leads to the activation of most peripheral T cells (mainly CD4 memory) by promoting a persistent intracellular calcium increase via two independent signaling pathways. The activation of these pathways, one activated by IFNgamma and the other by the combination TNFalpha/IL-2/IL-6, is independent from myelin antigens and precedes by 2 weeks phases of disease activity (eg, clinical relapses and/or appearance of gadolinium-enhancing lesions on brain magnetic resonance imaging scans during 1 year of follow-up). Our results indicate that an appropriate combination of the four cytokines, three with a proinflammatory profile and one necessary for T-cell growth and differentiation, can activate in an antigen-independent fashion most peripheral T cells from MS patients. This mechanism is likely to contribute to the recruitment of nonspecific lymphocytes into the cellular activation processes leading to CNS demyelination and may represent a major target for immune intervention in MS.

Antigens↗
PubMed1998

Magnetization transfer changes in the normal appearing white matter precede the appearance of enhancing lesions in patients with multiple sclerosis.

Serial monthly magnetization transfer (MT) imaging was performed to evaluate whether a change of the normal appearing white matter (NAWM), which precedes the appearance of enhancing lesions, is seen in patients with multiple sclerosis (MS). Every 4 weeks for 3 months, 10 patients with relapsing-remitting MS were scanned with a T1-weighted sequence, 20 minutes after injection with 0.3 mmol/kg gadolinium-DTPA (Gd-DTPA). During each of the monthly sessions, MT and dual echo scans were also performed before Gd-DTPA injection. On coregistered images, the MT ratio (MTR) was measured in NAWM subsequently involved by enhancing lesions, in NAWM areas on the same slices but outside any present or future MR abnormality, and in enhancing lesions at the time of their appearance. Forty-eight new enhancing lesions with no corresponding abnormalities on previous scans were identified. Their average MTR was 33.1% (+/-8.4%). Three, 2, and 1 month before enhancement appearance, the mean MTR in NAWM, measured from areas corresponding to future enhancing lesions, was significantly lower than the mean MTR in NAWM outside enhancing areas; the MTR decreased steadily as the time when the enhanced lesion approached. These results suggest that changes in the NAWM of patients with MS occur before lesions become evident on conventional MRI scans.

Adult↗
PubMed1998

A gene therapy approach to treat demyelinating diseases using non-replicative herpetic vectors engineered to produce cytokines.

A successful gene therapy approach in organ-specific autoimmune diseases, such as multiple sclerosis (MS), encompasses the inhibition of the autoreactive T cells or the modification of the target organ cells by the introduction of exogenous 'protective' genes. In MS, an autoimmune disease of the central nervous system (CNS), the inciting autoantigen is still unknown and therefore the isolation of autoreactive T cells may only be inferential. At present, gene therapy approaches in MS should therefore aim to the modification of the target organ. Possible candidate genes to be transferred within the CNS of MS patients are those coding for anti-inflammatory cytokines (i.e. interleukin-4, interleukin-10, transforming growth factor beta) which have been shown to ameliorate demyelinating diseases at least in experimental models. However, a limiting factor for this therapy is the difficulty to reach the CNS. A gene therapy approach using viral vectors able to infect post-mitotic cells, such as those present within the CNS, without inducing toxic reactions, may overcome this limitation. We propose to use non-replicative herpetic vectors, which represent a viable gene-transfer alternative to the classical retroviral and adenoviral vectors. Key advantages are their size, able to accommodate multiple foreign genes, and their ability to infect post-mitotic cells such as those present within the CNS. We first transferred a gene coding for interleukin-4 within the CNS of mice undergoing experimental allergic encephalomyelitis, an animal model for MS, using non-replicative Herpes Simplex Virus type 1-derived vectors. We found that this approach ameliorates the disease course and delays the disease onset. The establishment of this technique to deliver anti-inflammatory cytokines within the CNS using herpetic vectors should clarify the role of individual cytokines in the demyelinating process and allow assessment of whether gene therapy using herpetic vectors is a feasible and safe approach to treat human demyelinating disorders.

Animals↗
PubMed1997

Tumor necrosis factor alpha and its receptors in relapsing-remitting multiple sclerosis.

In the attempt to further characterize the extent and timing of tumor necrosis factor (TNF)alpha-system activation during multiple sclerosis (MS), we performed a cross-sectional and a longitudinal study in a total of 73 relapsing-remitting MS patients. We assessed serum levels of soluble TNFalpha, soluble TNFalpha receptor 1 (R1) and soluble TNFalpha receptor 2 (R2) in 65 relapsing-remitting MS patients in different phases of disease. TNFalpha, R1 and R2 serum levels measured in MS patients did not differ from those measured in healthy individuals and did not correlate with (a) clinical relapses, (b) presence of gadolinium-enhancing brain-magnetic resonance imaging (MRI) lesions, and (c) bioactivity of TNFalpha. We also measured in 8 additional relapsing-remitting MS patients peripheral blood mononuclear cells (PBMC) mRNA levels of TNFalpha, R1 and R2 every 15 days for one year. In 4 of these patients we also measured levels of soluble TNFalpha, R1 and R2 every 15 days for 5 months across a clinical exacerbation. PBMC TNFalpha, R1 and R2 mRNA levels and serum levels of soluble R1 and R2, but not TNFalpha, fluctuated concordantly (P<0.05) and peaked a mean of 6 weeks before clinical and MRI evidence of disease activity. Moreover, we found a significant positive correlation between cumulative TNFalpha and R2 mRNA levels (measured during the follow-up period in the 8 MS patients studied serially) and the number of clinical attacks recorded in these patients during the study. Our data show that serum levels of soluble TNFalpha, R1, and R2 in MS patients do not differ from those of healthy individuals. However, although within normal values, the transcription and production rate of all these molecules fluctuate concordantly in the peripheral blood during the course of the disease (with the exception of soluble TNFalpha) and their maximal elevation significantly precedes the occurrence of clinical exacerbations. It is not clear whether soluble TNFalpha escapes recognition by commonly used assays or is simply not released in its soluble form in MS patients. In any case, measurement of TNFalpha mRNA levels and R1 and R2 mRNA and protein levels appears to be a better indicator of disease fluctuations during the course of MS than assessments of soluble TNFalpha protein.

Adult↗
PubMed1997

A magnetization transfer study of white matter in siblings of multiple sclerosis patients.

In this study, we evaluated magnetization transfer ratio values in the brain white matter of siblings of multiple sclerosis (MS) patients and compared them to those obtained in sex- and age-matched normal controls. No statistically significant difference was found between the two groups for all the white matter areas studied (frontal and occipital lobes, centrum semiovale, periventricular white matter, internal capsule, genu and splenium of the corpus callosum).

Adult↗
PubMed1997

Occurrence and clinical relevance of an interleukin-4 gene polymorphism in patients with multiple sclerosis.

An epistatic gene interaction has been advocated to explain disease susceptibility in multiple sclerosis (MS). Cytokine genes are possible candidates due to the central role played by cytokines in the regulation of the immune-mediated pathogenetic process leading to central nervous system demyelination in these patients. Since interleukin (IL)-4 gene polymorphisms have been associated with immune-mediated diseases, we have analysed the relationship between a variable number of tandem repeat polymorphism of the IL-4 gene and clinical and physiological features of 256 sporadic MS patients and 146 healthy controls. Genotype frequencies were similar between the MS group and healthy controls. However, in MS patients a positive and significant correlation (r = 0.91; p < 0.001) was found between the carriage rate of the IL-4 B1 allele (from 0.21 to 0.36) and age of disease onset. No association was found between IL-4 alleles and disease progression, sex or ethnic background of the patients. Our results show that the IL-4 B1 allele is associated with late onset of MS and therefore might represent a modifier of age of onset rather than a susceptibility factor for patients with MS.

Adult↗
PubMed1997

Antibodies to 125I-glutamic acid decarboxylase in patients with stiff man syndrome.

Antibodies to glutamic acid decarboxylase (GAD) are found in about 40% of patients with stiff man syndrome. A new assay involving immunoprecipitation of (125)I-glutamic acid decarboxylase was used to measure anti-GAD antibodies in 18 patients with stiff man syndrome. Of the eight serum samples from patients with stiff man syndrome, that had previously been found positive by immunoprecipitation of (35)S-GAD, seven were strongly positive with (125)I-GAD and one gave an equivocal result. Other serum samples from patients with stiff man syndrome and from controls were negative except one from a patient who had a thymoma, acquired neuromyotonia, and myasthenia gravis. Nine of 35 serum samples referred for testing were positive; in two of these the serum titre was 20-50 times higher than that in the CSF. This assay should prove useful in the diagnosis, management, and investigation of stiff man syndrome.

Antibodies↗
PubMed1997

Interferon-gamma induced increases in intracellular calcium in T lymphocytes from patients with multiple sclerosis precede clinical exacerbations and detection of active lesions on MRI.

BACKGROUND: Interferon (IFN)-gamma exerts a multiplicity of actions potentially relevant for the pathogenesis of multiple sclerosis, including the expression of a transplasmalemma calcium (Ca2+) influx leading to an intracellular Ca2+ ([Ca2+]i) increase able to lower T lymphocyte threshold of excitability. It has been previously shown in a cross sectional cumulative study that this influx is associated with clinical and MRI evidence of disease activity. METHODS: To evaluate the temporal relation between disease activity and the IFN-gamma activated Ca2+ influx in individual patients, a fluorimetric analysis was performed on peripheral blood lymphocytes from eight patients with relapsing-remitting multiple sclerosis every 15 days for one year. RESULTS: Fluctuations of the influx were correlated with clinical events and monthly enhanced brain MRI. The influx was detected a mean of 10.4 (range 7-17) times per patient during our analysis. In 61% of the occasions, influx induced [Ca2+]i increases were recorded in each patient in more than two consecutive measurements, determining sustained [Ca2+]i increases lasting for a mean of 31.5 days. Peak [Ca2+]i increases preceded clinical attacks (P=0.04) or maximal detection of brain MRI enhancing lesions (P=0.05) by a mean of 30.8 and 34.2 days respectively. Spectral analysis of time series further indicated that the fluctuation frequency of [Ca2+]i increases due to the influx over time were superimposable on the appearance of new MRI lesions in all patients and confirmed that in two thirds of the patients these [Ca2+]i increases occurred significantly before (P<0.005) or concurred with new lesion appearance. Finally, the overall presence of the influx throughout the follow up period correlated (P=0.03) with the patients' exacerbation rates. CONCLUSIONS: Intracellular events leading to T lymphocyte activation in multiple sclerosis occur in the peripheral blood before CNS specific events become evident and are, in part, sustained by cytokine induced Ca2+ mediated phenomena.

Adult↗