PubMed Health⌕ Search

Biomedical subjects

M Pietropaolo

Publications and source records attributed to M Pietropaolo.

At least 37 records · Page 2Linked to original sources
PubMed1998

Autonomic function and autoantibodies to autonomic nervous structures, glutamic acid decarboxylase and islet tyrosine phosphatase in adolescent patients with IDDM.

Recent studies have linked autoimmunity to nervous tissue structures and diabetic autonomic neuropathy, but data on the early stage of IDDM and on the natural history of this association are not available. For this reason, we investigated autonomic nervous function, and the presence of autoantibodies to sympathetic and parasympathetic nervous structures, to glutamic acid decarboxylase (GAD) and tyrosine phosphatase (IA-2/ICA512) in 85 adolescents with insulin-dependent diabetes mellitus (IDDM) (mean age 14.7+/-1.6 yr, mean duration of diabetes 6.8+/-3.5 yr), and 45 age and sex-matched healthy subjects. Nervous tissues autoantibodies were detected using an indirect immunofluorescent complement-fixation technique, with monkey adrenal gland, rabbit cervical ganglia and vagus nerve as substrates. GAD and IA-2/ICA512 autoantibodies were detected by radioimmunoprecipitation assay. Seven patients (8%) had anti-vagus nerve autoantibodies, 7 other patients (8%) had anti-cervical ganglia autoantibodies, while all controls were negative (P < 0.05). Anti-adrenal medulla antibodies were detected in 16 patients (19%) and in 2 control subjects (P<0.02). None of the patients had autonomic symptoms. When patients were divided according to the presence or absence of autoantibodies, values of the cardiovascular tests (deep breathing, 30:15 ratio, Valsalva ratio) were similar in the two groups and similar to those in healthy subjects. However, when considered together, patients positive for one or more autoantibody showed a trend for lower values of deep breathing test and 30:15 ratio test, compared with healthy control subjects, which failed to reach conventional significance values (P=0.17 and P=0.07, respectively). No correlation was found between cardiovascular parameters and metabolic control or diabetes duration. There was no association between autoimmunity to nervous tissue structures and presence of GAD and IA-2/ICA512 Ab, and no correlation between these two autoantibodies and values of cardiovascular tests. Our data indicate that autonomic dysfunction is not a characteristic of young diabetic patients, but that autoantibodies against autonomic nervous structures are present during the first 1 to 15 yr of diabetes. GAD and tyrosine phosphatase appear to be excluded as target autoantigens within autonomic structures. Follow-up studies are required to evaluate future autonomic dysfunction and symptoms in these patients, and to establish whether the subtle autonomic dysfunction detected and/or the nervous tissue autoantibodies, are predictive of the development of this complication.

Adolescent↗
PubMed1998

Combined analysis of GAD65 and ICA512(IA-2) autoantibodies in organ and non-organ-specific autoimmune diseases confers high specificity for insulin-dependent diabetes mellitus.

There is evidence that insulin-dependent diabetes mellitus (IDDM) may develop in association with other non-beta-cell-specific autoimmune diseases. We aimed to assess whether autoantibodies to the islet cell antigens glutamic acid decarboxylase (Mr 65,000 isoform) (GAD65) and ICA512(IA-2), present alone or in combination, are limited to IDDM or also occur in other organ- or non-organ-specific autoimmune disorders. We determined the frequency of these autoantibodies by radioimmunoassay in 199 sera from patients with autoimmune thyroid diseases (AITD), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and primary biliary cirrhosis (PBC), and compared the results with those from 507 newly diagnosed patients with IDDM and 280 healthy controls. ICA512(IA-2) autoantibodies were detected exclusively in AITD with concurrent IDDM, but not in other autoimmune diseases without IDDM, whereas GAD65 autoantibodies exceeded the limit of normal in 67.7% (21 of 31) of patients with AITD who also had IDDM and in 5.5% (three of 55) of patients with PBC. The frequency of either GAD65 and/or ICA512(IA-2) autoantibodies was significantly higher in patients with AITD who also had IDDM (27 of 31, 87.1%) than in those with AITD alone (one of 53, 1.9%; P<10(-6)), but was not significantly different from those patients with newly diagnosed IDDM (418 of 507, 82.4%). Neither patients with organ- or non-organ-specific autoimmune diseases without IDDM nor healthy controls had autoantibodies against both GAD65 and ICA512(IA-2). Despite the fact that one of the two autoantibodies was occasionally detected in patients with non-beta-cell-specific autoimmune diseases without IDDM, combined determination of GAD65 and ICA512(IA-2) autoantibodies specifically identified IDDM in the majority of patients with AITD. In conclusion, because of the strong association of IDDM with AITD, testing for multiple islet autoanti-bodies could be useful as a predictive marker for risk of progression to IDDM onset amongst patients with autoimmune thyroid disorders.

Adolescent↗
PubMed1998

Identification of a novel serine protease-like molecule in human brain.

Proteolysis of the amyloid beta protein precursor (APP) is a key event in the development of Alzheimer's disease. In our search for proteases that can cleave APP and liberate the amino terminus of the amyloidogenic beta protein, we characterized a calcium-dependent serine protease (CASP) which is present in reactive astrocytes and cross-reacts with anti-cathepsin G antibodies. We wanted to take advantage of this cross-reactivity to clone the cDNA of CASP and eventually evaluate its tissue distribution. Screening of two human fetal brain cDNA libraries with anti-cathepsin G antibodies led to the identification of a cDNA coding for a novel protein whose only homology to known proteins is to the active site of trypsin-type serine proteases. We called this protein the novel serine protease (NSP). NSP exists in at least three differentially spliced forms, one of which is expressed predominantly in brain and testis. Immunohistochemistry and immunoprecipitation with antibodies generated against NSP show that it is expressed and secreted by a variety of cells and that, in brain, it is found primarily in cerebrovascular smooth muscle cells and reactive astrocytes.

Amino Acid Sequence↗
PubMed1998

Islet cell autoimmunity in white and black children and adolescents with IDDM.

OBJECTIVE: To compare the frequency of islet cell antibodies (ICA) and antibodies to GAD65 and IA-2(ICA512) between black and white children and adolescents at the diagnosis of IDDM in a large consecutive series of cases from Children's Hospital of Pittsburgh. RESEARCH DESIGN AND METHODS: ICA and antibodies to GAD65 and IA-2 were measured in 437 white and black children and adolescents who were diagnosed with IDDM at < 19 years of age at Children's Hospital of Pittsburgh from January 1983 to December 1985, from January to December 1989, and from January 1996 to December 1997. RESULTS: The prevalence of ICA(H), GAD65, and IA-2 antibodies was significantly lower in blacks than whites at onset of the disease. In contrast, the prevalence of ICA(R) alone was higher in blacks. None of the antibodies were present in 12% of the blacks compared with 4% in whites. The same pattern was seen in both sexes. The prevalence of antibodies in white patients with onset of IDDM at <11 years of age was no different than in those who developed IDDM during adolescence. In contrast, black patients showed a significantly lower prevalence of almost all antibodies in the adolescent group. CONCLUSIONS: Black adolescents were more likely to not have antibodies, suggesting either that they have a nonautoimmune type of diabetes or that antibodies are not being detected by these assays.

Adolescent↗
PubMed1997

The insulin gene is transcribed in the human thymus and transcription levels correlated with allelic variation at the INS VNTR-IDDM2 susceptibility locus for type 1 diabetes.

Type 1, or insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease associated with loss of tolerance to several pancreatic islet cell molecules, including insulin, glutamic acid decarboxylase (GAD), ICA69 and the tyrosine phosphatase IA-2 (refs 1-3). Among several predisposing loci, IDDM2 maps to the insulin gene (INS) VNTR (variable number of tandem repeats) minisatellite on chromosome 11p15 (refs 4-9). Allelic variation at this VNTR locus correlates with steady-state levels of INS mRNA in pancreas and transfected rodent cell lines, but it is difficult to reconcile the association of lower INS mRNA levels in the pancreas with class III VNTRs that are dominantly protective from IDDM. We show that during fetal development and childhood, mRNAs for insulin and other islet cell autoantigens (GAD, ICA69, IA-2) are expressed at low levels in the human thymus. Critically, we also detect proinsulin and insulin protein. VNTR alleles correlate with differential INS mRNA expression in the thymus where, in contrast to the pancreas, protective class III VNTRs are associated with higher steady-state levels of INS mRNA expression. This finding provides a plausible explanation for the dominant protective effect of class III VNTRs, and suggests that diabetes susceptibility and resistance associated with IDDM2 may derive from the VNTR influence on INS transcription in the thymus. Higher levels of (pro)insulin in the thymus may promote negative selection (deletion) of insulin-specific T-lymphocytes which play a critical role in the pathogenesis of type-1 diabetes.

Aging↗
PubMed1996

Number of autoantibodies (against insulin, GAD or ICA512/IA2) rather than particular autoantibody specificities determines risk of type I diabetes.

We previously evaluated radioassays for insulin autoantibodies (IAA), glutamate decarboxylase autoantibodies (GAA) and ICA512bdc autoantibodies (ICA512bdcAA) in the prediction of type I diabetes. Among first degree relatives, the five year risk of diabetes was 0% if no autoantibody was positive, 15% if only one was positive, 44% if two were positive and 100% if all three were positive. We measured IAA, GAA and ICA512bdcAA in 45 patients with new onset type I diabetes (sampled within 7 days of insulin therapy), 882 first degree relatives of patients with type I diabetes, and 217 control subjects. ICA512bdc is a construct of the ICA512/IA2 molecule (amino acid residues 256-979), including the intracellular domain. Based on receiver-operating characteristic plots, there was no significant difference between the three assays in their ability to discriminate between disease and control subjects. The upper limits of normal for the assays were determined as the 99th percentile of levels in the control subjects or higher. Using these cut-offs, 76% of new onset patients were positive for two or more autoantibodies, and 98% were positive for one or more. In comparison, none of 198 control subjects tested for all three assays were positive for more than one autoantibody. In relatives with a single autoantibody, or exactly two autoantibodies, there was no difference in diabetes-free survival according to which one of the autoantibodies was present (P = 0.70, logrank test), or which particular combination of autoantibodies was present (P = 0.56, logrank test) respectively. Our conclusions were as follows: the number of autoantibodies (counting IAA, GAA and ICA512bdcAA) is important in prediction, rather than the particular autoantibody specificities present. Among patients with new onset insulin-dependent diabetes, the absence of any of these autoantibodies justifies the consideration of non-autoimmune forms of diabetes in the differential diagnosis.

Adolescent↗
PubMed1996

Monoclonal antibodies against the human metalloprotease EC 3.4.24.15 label neurofibrillary tangles in Alzheimer's disease brain.

Alzheimer's disease is characterized neuropathologically by the presence of neuritic and amyloid plaques, vascular amyloid, and neurofibrillary tangles in specific brain areas. The main constituent of amyloid deposits is amyloid beta protein, a 40-42 amino acid proteolytic product of the amyloid beta-precursor protein. In our search for proteases that can generate the N-terminus of amyloid beta protein (beta-secretases), we discovered a thiol-dependent metalloprotease that was identified, by peptide sequencing, as metalloendopeptidase EC 3.4.24.15. In vitro, the metalloprotease cleaves the methionine-aspartic acid bond in a 10 amino acid synthetic peptide, indicating that it could generate the N-terminus of amyloid beta protein, and generates amyloidogenic fragments from full-length recombinant amyloid beta-precursor protein. Mouse monoclonal antibodies produced against a unique synthetic peptide from the metalloprotease labeled various monkey tissues as detected by western blots and immunohistochemistry. Unexpectedly, two monoclonal antibodies, IVD6 and IIIF3, immunolabeled strongly intracellular neurofibrillary tangles, neurites of senile plaques, and neuropil threads, but not "ghost" tangles or amyloid in sections taken from Alzheimer's disease brain. This finding provides further evidence for the metalloprotease's relevance to Alzheimer's disease pathology, although the connection between tangle staining and the formation of amyloid beta protein remains to be elucidated.

Alzheimer Disease↗
PubMed1996

Identification of 3 beta-hydroxysteroid dehydrogenase as a novel target of steroid cell autoantibodies: association of autoantibodies with endocrine autoimmune disease.

Autoantibodies directed against steroid hormone-producing cells (SCA) detectable by immunofluorescence are typically found in a small proportion of patients with premature ovarian failure (POF) as well as in other endocrine autoimmune diseases. The SCA pattern stains cells in the outer zones of the adrenal cortex, ovary, and testis. To identify the molecular target of SCA, an adrenal complementary DNA expression library was screened using SCA-positive serum, and the steroid enzyme 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) was identified. Only 1 of 48 (2%) patients with idiopathic POF, not pre-selected for the presence of other autoimmune diseases, had SCA by immunofluorescence, whereas 10 of 48 (21%) had anti-3 beta HSD autoantibodies detectable by immunoblot using recombinant human enzyme compared with 6 of 115 (5%) control subjects (P = 0.002). Absorption of SCA-positive serum with recombinant human 3 beta HSD abolished the immunofluorescence pattern. We also examined the prevalence of anti-3 beta HSD autoantibodies in other endocrine autoimmune diseases. Two of 112 (2%) diabetic patients, but none of the thyroid or Addisonian patients, had SCA by immunofluorescence. Twenty-six (23%) diabetic subjects (P < 0.001 vs. controls), 3 of 18 thyroid patients (P > 0.05 vs. controls), and none of 4 Addisonian patients had anti-3 beta HSD autoantibodies. 3 beta HSD is the first steroid cell autoantigen defined at the molecular level to be associated with idiopathic POF occurring in the absence of other polyglandular diseases. Autoantibodies to 3 beta HSD in patients with other organ-specific autoimmune diseases indicate that the enzyme behaves as a typical target of polyendocrine autoimmunity. Anti-3 beta HSD autoantibodies in patients with POF may provide a marker of those subjects whose ovarian failure is autoimmune in origin and, as recent studies suggest, may be salvageable with glucocorticoid treatment.

3-Hydroxysteroid Dehydrogenases↗
PubMed1996

Gene expression of islet cell antigen p69 in human, mouse, and rat.

Based on the detection of specific antibodies and T-cell sensitization in patients with IDDM, islet cell antigen p69 (ICAp69) has been suggested to be a target antigen of diabetic autoimmunity. The biological function, tissue expression, and developmental kinetics of ICAp69 are largely unknown. We analyzed ICAp69 expression at the gene transcription and protein level in human and rodent tissues. By using template-calibrated quantitative reverse transcriptase polymerase chain reaction (RT-PCR), high levels of ICAp69 mRNA were found in human pancreatic islets and brain. In mouse and rat, ICAp69 gene expression peaked in islet cell lines followed by testis, islets, and brain. ICAp69 mRNA was found at low levels in other organs by RT-PCR but not by Northern blot analysis. In mice, ICAp69 transcription becomes detectable in fetal life, and fetal and adult gene expression patterns are similar. Western blot analysis of human and mouse tissues showed high expression of ICAp69 in brain, testis, pancreatic tissue, and islet cell lines. In these organs, ICAp69 immunoreactivity is predominately localized at the blood brain barrier (capillary endothelium), at the blood testis barrier (Sertoli cells and spermatids), and in pancreatic islets (beta-cells). The subcellular localization of ICAp69 to endoplasmic reticulum, Golgi complex, and vesicles by immune electron microscopy suggests a role of this neuroendocrine molecule in cellular protein traffic and processing.off

Animals↗
PubMed1996

Prediction of type I diabetes in first-degree relatives using a combination of insulin, GAD, and ICA512bdc/IA-2 autoantibodies.

Islet cell antibodies (ICAs) are predictive of type I diabetes in first-degree relatives, but this immunohistochemical assay has proven difficult to standardize. As an alternative, we assessed the use of radioassays for antibodies against three molecularly characterized islet autoantigens, including ICA512bdc (amino acid residues 256-979 of the IA-2 molecule, incorporating the intracellular domain). We measured insulin autoantibodies (IAAs), GAD autoantibodies (GAAs), and ICA512bdc autoantibodies (ICA512bdcAAs) by radioassay, in addition to ICAs, in 882 first-degree relatives of patients with type I diabetes, 50 of whom later developed diabetes with a median follow-up of 2.0 years (maximum 11.3 years). The cutoff for each radioassay was determined by testing >200 control subjects. When autoantibody frequencies among the relatives were analyzed according to relationship to the proband, the offspring of diabetic fathers had a higher frequency of ICA5I2bdcAAs (P = 0.008), IAAs (P = 0.0001) and GAAs (P = 0.0001) than the offspring of diabetic mothers. ICA512bdcAAs and IAAs both showed a significant association with HLA-DR4-DQ8 (P = 0.0005). Among relatives developing diabetes, 98% had one or more of IAAs, GAAs, or ICA512bdcAAs, and 80% had two or more of these autoantibodies, compared with none of the control subjects. Using survival analysis to allow for different lengths of follow-up, there was a significant increase in the risk of diabetes with the number of these autoantibodies present, comparing zero, one, two, and three autoantibodies (P < 0.0001, log-rank test), and by Cox regression analysis, this was independent of ICAs and age. For relatives with two or more of these autoantibodies, the risk of diabetes within 3 years was 39% (95% CI, 27-52) and the risk within 5 years was 68% (95% CI, 52-84). Relatives with all three autoantibodies had a risk within 5 years estimated to be 100%. The presence of low first-phase insulin release further increased the risk for relatives with one or two autoantibodies. We conclude that the presence of two or more autoantibodies (out of IAAs, GAAs, and ICA512bdcAAs) is highly predictive of the development of type I diabetes among relatives.

Adolescent↗
PubMed1995

Late progression to diabetes and evidence for chronic beta-cell autoimmunity in identical twins of patients with type I diabetes.

Previous studies suggest that after 6 years of discordance, identical twin pairs rarely become concordant for type I diabetes. With up to 39 years of follow-up from the onset of diabetes in the index twin, we determined how many discordant twins have evidence of beta-cell autoimmunity and how many develop overt diabetes. We longitudinally followed 23 pairs of identical twins (or triplets) that were selected from a total group of 30 pairs because they were discordant for type I diabetes when first ascertained. Seven developed diabetes after 3, 3, 7, 8, 9, 31 and 36 years of discordance. By survival analysis, the concordance after 10 years from the onset of diabetes in the index twin was estimated as 23% (95% confidence interval, 5-40%), increasing to 38% (95% confidence interval, 8-69%) after 31 years. Among 16 twins remaining nondiabetic at last follow-up (8-39 years of discordance), 12 were assessed with serial intravenous glucose tolerance tests and a total of 407 measurements by radioassay of antibodies against three defined autoantigens (glutamic acid decarboxylase, insulin, and the recently cloned molecule ICA512). Two-thirds (8 of 12) had evidence of beta-cell autoimmunity (persistently positive autoantibody levels) and/or first-phase insulin release less than the 1st percentile of control subjects. In summary, identical twins may develop diabetes after a prolonged period of discordance and approximately two-thirds of long-term discordant twins have evidence of persistent beta-cell autoimmunity and/or beta-cell damage. The concordance for beta-cell autoimmunity, therefore, is much higher than for overt diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

ICA512 autoantibody radioassay.

As part of a general program of screening islet expression libraries we have identified a clone from a lambda gt11 human islet expression library that reacts with human diabetic sera and, upon sequencing, was determined to be the neuroendocrine islet autoantigen ICA512 (islet cell antigen 512). In the current communication, we describe the development of a radioassay for autoantibodies to ICA512 (ICA512AA) using in vitro transcribed and translated protein for production of labeled antigen. Our initial results indicate that this radioassay is significantly more sensitive than the enzyme-linked immunosorbant assay, which uses a COOH-terminal fragment of ICA512. The ICA512AA radioassay uses a 96-well format with membrane separation of antibody bound from free antigen and should be readily adaptable to automated large-scale screening. Only 7 microliters of serum is required for triplicate determinations. In order to determine the specificity and sensitivity of this assay and estimate its positive predictive value, we have studied 42 new-onset diabetic patients, 33 first-degree relatives of diabetic patients followed to diabetes, 694 islet cell antibody-negative (ICA-) relatives, and 205 normal control subjects. Thirty-eight percent of new-onset patients and 48% of relatives followed to diabetes express autoantibodies to ICA512 exceeding the 99th percentile of the normal control subjects. In contrast, only 1.4% of ICA- first-degree relatives were positive for ICA512 autoantibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Synaptotrophic effects of human amyloid beta protein precursors in the cortex of transgenic mice.

The amyloid precursor protein (APP) is involved in Alzheimer's disease (AD) because its degradation products accumulate abnormally in AD brains and APP mutations are associated with early onset AD. However, its role in health and disease appears to be complex, with different APP derivatives showing either neurotoxic or neurotrophic effects in vitro. To elucidate the effects APP has on the brain in vivo, cDNAs encoding different forms of human APP (hAPP) were placed downstream of the neuron-specific enolase (NSE) promoter. In multiple lines of NSE-hAPP transgenic mice neuronal overexpression of hAPP was accompanied by an increase in the number of synaptophysin immunoreactive (SYN-IR) presynaptic terminals and in the expression of the growth-associated marker GAP-43. In lines expressing moderate levels of hAPP751 or hAPP695, this effect was more prominent in homozygous than in heterozygous transgenic mice. In contrast, a line with several-fold higher levels of hAPP695 expression showed less increase in SYN-IR presynaptic terminals per amount of hAPP expressed than the lower expressor lines and a decrease in synaptotrophic effects in homozygous compared with heterozygous offspring. Transgenic mice (2-24 months of age) showed no evidence for amyloid deposits or neurodegeneration. These findings suggest that APP may be important for the formation/maintenance of synapses in vivo and that its synaptotrophic effects may be critically dependent on the expression levels of different APP isoforms. Alterations in APP expression, processing or function could contribute to the synaptic pathology seen in AD.

Amyloid beta-Protein Precursor↗
PubMed1993

Preventive effects of azathioprine (AZA) on the onset of diabetes mellitus in NOD mice.

We have studied the effects of long-term treatment with azathioprine (AZA) vs cyclosporin A (CSA) vs placebo (PL), in three groups of 10 week old, prediabetic NOD mice. One of 8 AZA, none of 8 CSA and 7 of 11 PL treated mice developed overt diabetes (IDDM). Quantitative morphometric analysis conducted on mouse pancreatic histologic sections documented that extent and degree of islet beta-cell damage were incomparably less severe in the mice that received AZA or CSA compared to those treated with PL. Since early and prolonged treatment with AZA seems to prevent the onset of DM in NOD mice as nearly effectively as CSA, AZA, which is significantly safer than CSA, could replace the latter as a potential approach for the immunotherapy of IDDM.

Animals↗