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Pietro Invernizzi

Publications and source records attributed to Pietro Invernizzi.

At least 19 recordsLinked to original sources

Correlation of initial autoantibody profile and clinical outcome in primary biliary cirrhosis.

Although there have been significant advances in understanding the clinical and biochemical features of primary biliary cirrhosis (PBC), there is still a paucity of data on the usefulness of biomarkers as prognostic indicators. This is particularly important at the time of initial diagnosis. Indeed, the widespread use of antimitochondrial antibody testing has led to an earlier diagnosis of asymptomatic PBC and it is difficult to predict which patients will experience a benign versus a rapidly progressive course. To address this issue, we examined a unique population of 127 newly diagnosed patients with PBC during a 15-year period of observation that began in January 1990. Sera from these patients were analyzed for antimitochondrial, antinuclear, and anti-smooth muscle antibodies, and immunoblotting was performed for nuclear pore complex (NPC). The patients were then followed up longitudinally using biochemical liver function tests. No patient was under any medical therapy for PBC at the time of the initial sera collection. Data were analyzed based not only on the clinical features, but also the Mayo score and specific outcome measures, including time to death, need for liver transplantation, and complication free survival. Among patients with early disease, bilirubin increased to >2 mg/dL in the anti-NPC(+) patients (26% vs. 5%, P = .019). Anti-NPC antibodies remained stable or slightly increased over the period of observation. In condusion, anti-NPC identifies patients likely to experience an unfavorable clinical course and more rapid disease progression.

Adult↗

The X chromosome and systemic sclerosis.

PURPOSE OF REVIEW: Similar to the majority of autoimmune rheumatic diseases, systemic sclerosis is characterized by a striking female predominance superimposed on a predisposing genetic background. At least two genetic mechanisms have been proposed that play a role in susceptibility to systemic sclerosis; firstly the maintenance of immune tolerance via genes on the X chromosomes and, secondly, fetal microchimerism. Based on these lines of evidence, experimental efforts have been most recently dedicated to investigating the role of X chromosome abnormalities (i.e. monosomy rates and inactivation patterns) in autoimmunity. We will review herein the most recent data on the role of the X chromosome in systemic sclerosis onset and discuss the potential implications. RECENT FINDINGS: Women with systemic sclerosis manifest an enhanced rate of X monosomic cells in peripheral blood compared with healthy age-matched women. Furthermore, a severely skewed X chromosome inactivation pattern is found in women with systemic sclerosis. SUMMARY: These observations, reproduced in other female-predominant autoimmune diseases, strongly support the role of the X chromosome in conferring susceptibility to tolerance breakdown and open novel scenarios to emphasize the unknown etiopathogenesis of systemic sclerosis. The implications of these findings will be discussed.

Autoimmunity↗

X chromosome monosomy: a common mechanism for autoimmune diseases.

The majority of human autoimmune diseases are characterized by female predominance. Although sex hormone influences have been suggested to explain this phenomenon, the mechanism remains unclear. In contrast to the role of hormones, it has been suggested, based on pilot data in primary biliary cirrhosis, that there is an elevation of monosomy X in autoimmune disease. Using peripheral white blood cells from women with systemic sclerosis (SSc), autoimmune thyroid disease (AITD), or healthy age-matched control women, we studied the presence of monosomy X rates using fluorescence in situ hybridization. We also performed dual-color fluorescence in situ hybridization analysis with a chromosome Y alpha-satellite probe to determine the presence of the Y chromosome in the monosomic cells. In subsets of patients and controls, we determined X monosomy rates in white blood cell subpopulations. The rates of monosomy X increased with age in all three populations. However, the rate of monosomy X was significantly higher in patients with SSc and AITD when compared with healthy women (6.2 +/- 0.3% and 4.3 +/- 0.3%, respectively, vs 2.9 +/- 0.2% in healthy women, p < 0.0001 in both comparisons). Importantly, X monosomy rate was more frequent in peripheral T and B lymphocytes than in the other blood cell populations, and there was no evidence for the presence of male fetal microchimerism. These data highlight the thesis that chromosome instability is common to women with SSc and AITD and that haploinsufficiency for X-linked genes may be a critical factor for the female predominance of autoimmune diseases.

Adult↗

Antidiabetic thiazolidinediones induce ductal differentiation but not apoptosis in pancreatic cancer cells.

AIM: Thiazolidinediones (TZD) are a new class of oral antidiabetic drugs that have been shown to inhibit growth of same epithelial cancer cells. Although TZD were found to be ligands for peroxisome proliferator-activated receptor gamma (PPARgamma), the mechanism by which TZD exert their anticancer effect is presently unclear. In this study, we analyzed the mechanism by which TZD inhibit growth of human pancreatic carcinoma cell lines in order to evaluate the potential therapeutic use of these drugs in pancreatic adenocarcinoma. METHODS: The effects of TZD in pancreatic cancer cells were assessed in anchorage-independent growth assay. Expression of PPARgamma was measured by reverse-transcription polymerase chain reaction and confirmed by Western blot analysis. PPARgamma activity was evaluated by transient reporter gene assay. Flow cytometry and DNA fragmentation assay were used to determine the effect of TZD on cell cycle progression and apoptosis respectively. The effect of TZD on ductal differentiation markers was performed by Western blot. RESULTS: Exposure to TZD inhibited colony formation in a PPARgamma-dependent manner. Growth inhibition was linked to G1 phase cell cycle arrest through induction of the ductal differentiation program without any increase of the apoptotic rate. CONCLUSION: TZD treatment in pancreatic cancer cells has potent inhibitory effects on growth by a PPAR-dependent induction of pancreatic ductal differentiation.

Adenocarcinoma↗

Genetic polymorphisms influencing xenobiotic metabolism and transport in patients with primary biliary cirrhosis.

Epidemiological data suggest that environmental factors may trigger autoimmunity in genetically susceptible individuals. In primary biliary cirrhosis (PBC), it has been postulated that halogenated xenobiotics can modify self-molecules, facilitating the breakdown of tolerance to mitochondrial antigens. The transport and metabolism of xenobiotics is highly dependent on key genetic polymorphisms that alter enzymatic phenotype. We analyzed genomic DNA from 169 patients with PBC and 225 geographically and sex-matched healthy subjects for polymorphisms of genes coding for cytochromes P450 (CYPs) 2D6 (CYP2D6*4, CYP2D6*3, CYP2D6*5, and CYP2D6*6) and 2E1 (cl/c2), multidrug resistance 1 (MDR1 C3435T) P-glycoprotein, and pregnane X receptor (PXR C-25385T, C8055T, and A7635G). We compared the genotype frequencies in patients and controls and also correlated polymorphisms with PBC severity. The distributions of the studied genotypes did not significantly differ between patients and controls. However, when clinical characteristics of patients with PBC were compared according to genotype, the CYP2E1 c2 allele was associated with signs of more severe disease. In conclusion, genetic polymorphisms of CYP 2D6 and 2E1, PXR, and MDR1 do not appear to play a role in the onset of PBC.

Aged↗

Genes and goals: an approach to microarray analysis in autoimmunity.

A significant body of data on gene expression patterns in autoimmune diseases has been generated by microarray analysis. Although results are very promising, there are many factors that have detracted from the data. Indeed, no common methodological directions are available. Similarly, collection techniques, processing methods, and statistical approaches are often different. The impact of future studies will depend on the comparison of large datasets to validate results and must include rigorous statistical analysis. To better illustrate the issue we review herein the gene expression patterns observed in five representative autoimmune diseases, i.e. systemic lupus erythematosus, multiple sclerosis, rheumatoid arthritis, dermatomyositis, and primary biliary cirrhosis. We also emphasize how, once potential chromosome regions or pathways are identified, specific array design will be a powerful resource when used on large and representative populations.

Animals↗

Genetic polymorphisms of toll-like receptor 9 influence the immune response to CpG and contribute to hyper-IgM in primary biliary cirrhosis.

The serum hallmark of primary biliary cirrhosis (PBC) is the presence of anti-mitochondrial antibodies (AMA), found in 95% of patients. However, nearly every patient with PBC, including those who are AMA-negative, has an elevation in serum IgM. This hyper-IgM is neither representative of other Ig isoforms, nor is due to the levels of AMA. In fact, we have recently reported that the hyper-IgM is an innate immune response and can be induced with CpG-B with concurrent up-regulation of toll-like receptor 9 (TLR9). Based on these observations, we performed a two-tier study. First, we quantitated TLR9 genotypes in patients with PBC and controls and correlated these data with the B cell response to CpG-B. Second, based on these data, we performed an extensive TLR9 genotyping in a large cohort of patients and controls. We report herein that the 2848 AA TLR9 genotype is associated with enhanced gene expression and higher frequency of intracellular IgM(+) B cells following CpG stimulation. Interestingly, however, despite the functional association, there is no difference in the distribution of TLR9 genotypes between patients and controls. Our data emphasize the importance of dissecting the innate immune response in PBC.

Adult↗

From bases to basis: linking genetics to causation in primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is a multifactorial autoimmune disease with inherited and environmental components in pathogenesis. It is exceptional among autoimmune diseases in showing strong heritability according to familial occurrence and monozygotic twins concordance, yet with weak associations with the usual genetic risk elements for autoimmunity, such as the HLA alleles. Among the latter, there is risk (at least in some populations) conferred by HLA DRB1*08 and possibly some protection by DRB1*11. However, the inconsistency among studies on HLA is surprising, given that PBC is a relatively homogenous disease entity. Among non-HLA genes, some studies implicate polymorphisms of genes for cytotoxic T-lymphocyte antigen-4, interleukin-2, or interleukin-10; polymorphisms of the vitamin D receptor could synergize with low sunlight exposure to create deficiency of the immunoregulatory factor, activated vitamin D. A new lead is available from the finding in female subjects with PBC of an increase in the degree of monosomy of the X chromosome that is presumed to carry immune response genes. A further suggested source of inquiry is the apparent protection of African-American women from PBC. Finally, data on inheritance should be sought in PBC by descent methodology, rather than by cross-sectional association studies in cases and control subjects, and based on analysis of a large number of families with an affected member through a worldwide effort.

Autoimmune Diseases↗

Genetics and geoepidemiology of primary biliary cirrhosis: following the footprints to disease etiology.

The etiopathogenesis of primary biliary cirrhosis (PBC), an autoimmune disease characterized by the progressive destruction of intrahepatic bile ducts, is still enigmatic. There is growing evidence that suggests that the disease results from a combination of genetic and environmental factors. PBC should be regarded as a peculiar, yet representative autoimmune disease. For example, the relative risk for siblings and the concordance rate in monozygotic twins in PBC are among the highest reported in autoimmune conditions. Association studies for specific genes have provided weak associations, which often are limited to specific geographical areas. Interestingly, PBC epidemiology also presents a geographical pattern; it is more common in the northern parts of Europe and United States. In this article, we critically review available evidence regarding genetics and geoepidemiology in PBC. We also submit possible interpretations of data, new developments and theories, and attempt to indicate directions for future research efforts.

Europe↗

Antinuclear antibodies in primary biliary cirrhosis.

Patients with primary biliary cirrhosis (PBC) generate a variety of autoantibodies, which are primarily directed against mitochondrial antigens (AMA). However, a subgroup of patient sera are also positive for antibodies to nuclear components (ANAs). At indirect immunofluorescence (IIF), PBC sera mostly produce homogeneous, nuclear dot, speckled, centromere, or rim-like patterns. During the last two decades, a number of nuclear structures have been recognized as specific targets of ANA in PBC. These include Sp100 and promyelocytic leukemia proteins, which generate a nuclear dot IIF pattern, and two components of the nuclear pore complex specifically associated with a perinuclear pattern (i.e., gp210 and p62). In recent years, the clinical significance of ANA in PBC has been widely investigated and data indicate that, unlike AMAs, PBC-specific ANAs correlate with disease severity and may therefore be a marker of poor prognosis.

Antibodies, Antinuclear↗

SNP analysis of genes implicated in T cell proliferation in primary biliary cirrhosis.

Previous studies on primary biliary cirrhosis (PBC) have focused on the role of T lymphocytes as potential effectors of tissue injury. We hypothesized that single nucleotide polymorphisms (SNPs) of genes involved in lymphocyte proliferation would be responsible for uncontrolled expansion of T cells and autoreactivity. To address this, we genotyped DNA from 154 patients with PBC and 166 ethnically matched healthy controls for SNPs of five candidate genes (60G/A CTLA-4, 1858 C/T LYP, -IVS9 C/T foxp3, p1323 C/G ICOS and -9606 T/C CD25) using a TaqMan assay. We report herein a statistically significant decrease in homozygosity rate for the 60A*CTLA-4 allele in patients with PBC compared to controls (p = 0.0411). Moreover, we found a significant association of the same allele and of the LYP*T allele with anti-mitochondrial antibody (AMA) serum negativity (p = 0.0304 and 0.0094, respectively). No association between any of the other studied SNPs and PBC susceptibility, progression, or AMA status was observed. In conclusion, given the high prevalence of SNPs in CTLA-4 detected in numerous autoimmune diseases, we encourage a more detailed genetic analysis of this candidate gene. Further, although obtained from a limited number of AMA-negative subjects, our data suggest a potential genetic heterogeneity for this specific subgroup of patients with PBC.

Aged↗

Primary biliary cirrhosis: solving the enigma.

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease, most commonly affecting female patients between 40 and 60 years of age. Patient sera present autoantibodies against mitochondrial antigens (AMA) and elevated serum IgM. Histologic studies demonstrate progressive destruction of small- and medium-sized intrahepatic bile ducts and, ultimately, liver cirrhosis. The precise mechanisms leading to selective destruction of such biliary epithelial cells are still unknown, although a number of immunomediated pathways have been proposed. Genetic background is critical in determining susceptibility to the disease, although no clear association with haplotypes of the major histocompatibility complex has been identified. Molecular mimicry by either infectious agents or xenobiotics has been proposed as a means of breaking tolerance in genetically predisposed individuals, thus leading to the onset of PBC. In this review, available data and current theories regarding the immunomediated pathogenesis of PBC will be described.

Antibodies, Antinuclear↗

Soluble CD40L in plasma of patients with primary biliary cirrhosis.

CD40 ligand (CD40L) is expressed by activated T cells and interacts with the CD40 molecule present on B cells and endothelial cells, promoting immunoglobulin switching in the former and cytokine upregulation in the latter. CD40L exists in both a soluble (sCD40L) and a membrane-bound form. Because primary biliary cirrhosis (PBC) is characterized by targeting of small intrahepatic bile ducts by autoreactive T cells, plasma concentrations of sCD40L were investigated using enzyme-linked immunosorbent assay (ELISA) to measure plasma concentrations of sCD40L in 12 patients with PBC and 12 healthy controls. No difference could be detected between plasma concentrations of sCD40L in patients versus controls (P = 0.977). No correlation between age and plasma levels of sCD40L could be identified (P = 0.24). We concluded that PBC patients do not exhibit higher plasma concentrations of sCD40L than age-matched controls, a finding common to several autoimmune diseases. Further investigation of the CD40-CD40L system is strongly encouraged.

Adult↗

Decreased serum leptin levels in primary biliary cirrhosis: a link between metabolism and autoimmunity?

Primary biliary cirrhosis (PBC) is an autoimmune liver disease of unknown etiology resulting in the progressive destruction of the intrahepatic bile ducts and leading to chronic cholestasis and ultimately liver cirrhosis and failure. The immune response in PBC seems to be mediated by autoantibodies as well as autoreactive T lymphocytes directed against mitochondrial antigens in biliary epithelial cells, primarily PDC-E2. Experimental evidence suggests a role of the hormone/cytokine leptin in autoimmune diseases. Leptin is an adipocyte-derived molecule that acts as a hormone influencing food intake and energy metabolism as well as a cytokine with pro-inflammatory, immune-regulatory functions. To study serum leptin in PBC and its association with disease severity, we evaluated serum levels in 37 patients with PBC (27 with no signs of fibrosis or cirrhosis at histologic examination) and 37 age- and sex-matched healthy controls using a validated ELISA method. We found that patients with PBC had significantly lower leptin serum levels compared with healthy controls (13.6 +/- 13.8 vs. 17.6 +/- 11.6; P < 0.05). No correlation between disease severity and serum leptin levels was found. This study has demonstrated that leptin levels are decreased in the serum of patients with PBC but do not seem to be associated with disease severity. Data do not seem to indicate a direct role of leptin in the perpetuation of the autoimmune response in PBC. However, further studies are warranted to further characterize the functions of leptin during the natural history of autoimmunity.

Adult↗

The enigma of primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is a chronic cholestatic disease characterized by a striking predominance in female patients (with most cases diagnosed between ages 40 and 60 yr) as well as serum auto-antibodies to mitochondrial antigens, elevated serum immunoglobulin M,progressive destruction of intrahepatic bile ducts, and, ultimately, liver cirrhosis and failure(1). The precise mechanisms leading to selective destruction of biliary epithelial cells lining intrahepatic bile ducts are still unknown, although numerous immunomediated pathways have been proposed. Genetic background appears to be important in determining susceptibility to the disease (2), but no clear association with alleles in the major histocompatibility complex has been identified. Molecular mimicry either by infections (3) or xenobiotics (4) has been proposed to be capable of breaking tolerance in genetically predisposed individuals, thus leading to onset of PBC. This article describes and discusses the available data regarding the immunomediated pathogenesis of PBC (with particular attention to auto-antibodies and autoreactive T-cells) and presents the recent evidence indicating a role for either xenobiotic chemicals or novel infectious agents in the induction of the disease.

Animals↗

Frequency of monosomy X in women with primary biliary cirrhosis.

The mechanisms that cause the female predominance of primary biliary cirrhosis (PBC) are uncertain, but the X chromosome includes genes involved in immunological tolerance. We assessed the rate of X monosomy in peripheral white blood cells from 100 women with PBC, 50 with chronic hepatitis C, and 50 healthy controls, by fluorescence in-situ hybridisation. Frequency of X monosomy increased with age in all groups, but was significantly higher in women with PBC than in controls (p<0.0001); age-adjusted back-transformed mean frequencies were 0.050 (95% CI 0.046-0.055) in women with PBC, 0.032 (0.028-0.036) in those with chronic hepatitis C, and 0.028 (0.025-0.032) in controls. We suggest that haploinsufficiency for specific X-linked genes leads to female susceptibility to PBC.

Adult↗

Primary biliary cirrhosis: does X mark the spot?

Primary biliary cirrhosis (PBC) is an autoimmune disease of unknown etiology leading to progressive destruction of intrahepatic bile duct, with cholestasis, cirrhosis, and eventually liver failure. Epidemiological data indicate that environmental factors trigger autoimmunity in genetically susceptible individuals, although no definitive association of PBC with specific genes has been found. Further, no convincing explanation has been provided for the strong female predominance observed in the prevalence of PBC. However, we recently suggested that the enhanced monosomy X in peripheral white blood cells, and particularly in lymphocytes, of affected women might play a role in the induction of PBC. Such observations appear independent from the degree of cholestasis and specific for PBC. In this review we discuss the implications of these findings and their immunological implications.

Autoimmune Diseases↗