Biomedical subjects

Gianni Carraro

Publications and source records attributed to Gianni Carraro.

At least 19 recordsLinked to original sources

PubMed2006

Levels of mesenchymal FGFR2 signaling modulate smooth muscle progenitor cell commitment in the lung.

Fibroblast growth factor (FGF) signaling has been shown to regulate lung epithelial development but its influence on mesenchymal differentiation has been poorly investigated. To study the role of mesenchymal FGF signaling in the differentiation of the mesenchyme and its impact on epithelial morphogenesis, we took advantage of Fgfr2c(+/Delta) mice, which due to a splicing switch express Fgfr2b in mesenchymal tissues and manifest Apert syndrome-like phenotypes. Using a set of in vivo and in vitro studies, we show that an autocrine FGF10-FGFR2b signaling loop is established in the mutant lung mesenchyme, which has several consequences. It prevents the entry of the smooth muscle progenitors into the smooth muscle cell (SMC) lineage and results in reduced fibronectin and elastin deposition. Levels of Fgf10 expression are raised within the mutant mesenchyme itself. Epithelial branching as well as epithelial levels of FGF and canonical Wnt signaling is dramatically reduced. These defects result in arrested development of terminal airways and an "emphysema like" phenotype in postnatal lungs. Our work unravels part of the complex interactions that govern normal lung development and may be pertinent to understanding the basis of respiratory defects in Apert syndrome.

Animals↗

PubMed2006

Age-dependent decrease in the ghrelin gene expression in the human adrenal cortex: a real-time PCR study.

Numerous lines of evidence indicate that ghrelin, an endogenous ligand of the growth hormone-secretagogue receptor, is expressed in the human and rat adrenal cortex. In this study, we examined whether ghrelin gene expression undergoes changes in the human adrenal cortex during aging. Semi-quantitative real-time reverse transcription-polymerase chain reaction demonstrated a highly significant negative correlation between ghrelin mRNA and age in adrenal cortex of 27 patients (aged from 33 to 82 years), who underwent unilateral adrenalectomy/nephrectomy for kidney cancer. No significant differences in the level of adrenal ghrelin expression were observed between males and females. Since it has been previously shown that ghrelin exerts a marked growth-stimulating action on cultured adrenocortical cells, we hypothesize that the down-regulation of ghrelin gene transcription in adrenals could be associated with the reported decrease in adrenal DNA synthesis and mitogenic activity during aging.

Adrenal Cortex↗

PubMed2006

In vitro culture on Matrigel favors the long-term maintenance of rat zona glomerulosa-cell differentiated phenotype.

Zona glomerulosa (ZG) cells cultured on plastic within few days dedifferentiate losing their capacity to secrete aldosterone (ALDO) in appreciable amounts. Evidence indicates that extracellular matrix modulates the secretory behavior of adrenocortical cells cultured in vitro. Hence, we compared the morphology and function of rat ZG cells grown on plastic and Matrigel basement membrane matrix (hereinafter Matrigel) for up to 12 days. At day 3, no significant differences were observed between cells cultured on plastic and Matrigel. Starting from day 6, ZG cells cultured on plastic lost their ultrastructural differentiated features (mitochondria with tubular cristae, smooth endoplasmic reticulum cisternae and lipid droplets), exhibiting a fibroblast-like appearance. The mRNA expression of the main steroidogenic enzymes, as evaluated by real-time polymerase chain reaction, the baseline secretion of ALDO and other post-pregnenolone hormones, as evaluated by high pressure liquid chromatography, and the secretory response to ACTH, angiotensin-II and K(+), as evaluated by radioimmunoassay, displayed a time-dependent decrease. Matrigel was found to maintain unchanged both the ultrastructure and the expresion of steroidogenic enzymes of ZG cells until day 12 of culture. Baseline and agonist-stimulated steroid-hormone secretion decreased with the duration of culture on Matrigel, but was always higher than that of ZG cells grown on plastic. Hence, our study clearly indicates that the culture on Matrigel favors the maintenance of rat ZG-cell differentiated phenotype, allowing the conclusion that this technique is suitable for long-term in vitro investigations.

Adrenocorticotropic Hormone↗

PubMed2005

Regulatory mutations in transforming growth factor-beta3 gene cause arrhythmogenic right ventricular cardiomyopathy type 1.

OBJECTIVE: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetically heterogeneous disorder characterized by fibro-fatty replacement of the right ventricular myocardium, associated with high risk of sudden death. The objective of this study is to identify the gene involved in ARVD1, which has been elusive ever since its locus was mapped to chromosome 14q24.3. METHODS AND RESULTS: Mutation screening of the promoter and untranslated regions (UTRs) of the transforming growth factor-beta3 (TGFbeta3) gene was performed by direct sequencing of genomic DNA of one index case belonging to an ARVD1 family including 38 members in four generations. We detected a nucleotide substitution (c.-36G>A) in 5' UTR of TGFbeta3 gene, invariably associated with the typical ARVC clinical phenotype in the affected family members, according to the established diagnostic criteria. Investigation extended to 30 unrelated ARVC patients, performed by denaturing high-performance liquid chromatography (DHPLC), led to the identification of an additional mutation (c.1723C>T) in the 3' UTR of one proband. Neither nucleotide change was found in 300 control subjects. In vitro expression assays with constructs containing the mutations showed that mutated UTRs were twofold more active than wild-types. CONCLUSION: We identified TGFbeta3 as the disease gene involved in ARVD1. The identification of a novel ARVC gene will increase the power of the genetic screening for early diagnosis of asymptomatic carriers among relatives of ARVC patients.

3' Untranslated Regions↗

PubMed2005

Similar sequence-free amplification of human glyceraldehyde-3-phosphate dehydrogenase for real time RT-PCR applications.

One of the major applications of real time polymerase chain reaction (PCR) is relative quantification, where the expression of a target gene is determined as a ratio to a stably expressed reference gene, the so-called housekeeping gene. Glyceraldehyde-3-phosphate dehydrogenase (GAPD) is a glycolytic enzyme, which is active in all mammalian tissues and is frequently used as housekeeping gene in expression studies. The functional locus maps to human chromosome 12p13, but several GAPD-related sequences, including processed pseudogenes, GenBank homologous sequences and computationally predicted sequences are present along the human genome. Due to the high level of GAPD-related sequences it is very important to avoid genomic DNA amplification when GAPD is used as endogenous control in mRNA quantification. We have outlined a GAPD couple of primers that avoid any genomic DNA amplification for real time reverse transcription PCR applications by SYBR-Green Dye. These new designed primers are an useful and chip alternative to probe technologies, and can carry out specific and reproducible data in mRNA expression studies.

Base Sequence↗

PubMed2005

Endothelin-1 and adrenomedullin enhance the growth of human adrenocortical carcinoma-derived SW-13 cell line by stimulating proliferation and inhibiting apoptosis.

The human adrenocortical carcinoma-derived SW-13 cell line is currently used to study the interrelationships occurring between cytokines and growth factors and endothelins (ET) and adrenomedullin (AM). SW-13 cells express either ET-1 and AM or growth factors, and several cytokines stimulate ET-1 and AM release from SW-13 cells. However, neither the morphology and steroid-hormone secretion of SW-13 cells nor the expression of ET and AM receptors and the effects of ET and AM on SW-13 cell growth have been investigated. Electron microscopy showed that SW-13 cells were deprived of the typical organelles involved in steroid-hormone synthesis (i.e. mitochondrial with tubular cristae, smooth endoplasmic reticulum and lipid droplets), their prominent ultrastructural features being rough endoplasmic reticulum cisternae, free ribosomes and mitochondria with laminar cristae. Accordingly, steroid-hormone secretion was very low: no cortisol was produced and only very small amounts of aldosterone and its precursors were released. No appreciable secretory response to physiological concentrations of ACTH was observed. Reverse transcription-polymerase chain reaction showed the expression of pro ET-1 and proAM genes, as well as detected the mRNAs of only the ET- and AM-receptor subtypes, which are currently thought to mediate the growth-promoting action of these peptides: i.e. the ETA and AM2 receptors. In keeping with these observations, both ET-1 and AM markedly stimulated the growth of SW-13 cells, by enhancing the proliferation and lowering the apoptosis rate. Taken together, our findings allow us to conclude that SW-13 cannot be used for investigating the mechanisms involved in the regulation of steroid-hormone secretion, but are a suitable and useful model to study the role of endogenous ET and AM systems in the autocrine-paracrine control of human adrenocortical-cell growth.

Adrenocortical Carcinoma↗

PubMed2005

Human adrenomedullin gene silencing by short interfering RNAs: a preliminary study.

Adrenomedullin (AM) is a regulatory peptide widely expressed, along its receptors, in cells and tissues, of which it controls many basic and specific functions acting in an autocrine-paracrine manner. However, the unequivocal demonstration of the physiological relevance of the regulatory role of AM would require the study of cells where endogenous AM system had been suppressed. Hence, we developed a protocol to silence the human AM gene by transfection with short interfering RNAs (siRNAs). Eight possible AM-siRNA sequences were designed: six siRNAs were synthesized in our laboratory and two were provided by Ambion. As positive control the suppression of the glyceraldehyde-3-phosphate dehydrogenase (GADPH) gene was tested using the Ambion Silencer GADPH siRNA kit. Cultured human embryonal kidney cell line HEK-293 and human umbilical vein endothelial cells (HUVECs) were transfected using either the Qiagen or the Ambion transfection reagent, and transfection visualization, carried out using Cy3-labeled siRNA and examining red fluorescence within the cells, showed that the former reagent was the most efficient. AM-gene silencing was determined in HUVECs by measuring AM mRNA levels in transfected and control cells by real-time polymerase chain reaction. Only Ambion siRNAs were effective, and the best AM-gene silencing (about 80%) was observed 48 or 72 h after transfection with 3 or 6 microg of siRNAs. The conclusion is drawn that siRNA technology can be useful in the investigations on AM functions, but that the complete suppression of the AM-gene transcription is very difficult to obtain.

Adrenomedullin↗

PubMed2005

Arginin-vasopressin regulates proliferative activity of the regenerating rat adrenal cortex.

Enucleation-induced adrenal regeneration is a classic model to investigate adrenocortical proliferation in vivo, which is dependent not only on pituitary ACTH release, but also on various other neural and endocrine signals. Arginin-vasopressin (AVP), mainly acting via V1 receptors, regulates hypothalamic-hypophyseal-adrenal axis function, acting on both its central and peripheral branches. Here, we studied whether endogenous AVP system modulates rat adrenal regeneration. Reverse transcription-polymerase chain reaction (PCR) detected only the mRNAs of V1a and V1b receptors in normal and regenerating adrenals. The expression was very low, and semi-quantitative conventional and real-time PCR showed that it was down-regulated in regenerating adrenals in relation to the time elapsed from enucleation. AVP (three subcutaneous injections 28, 16 and 4 h before sacrifice) raised metaphase index at day 5, but not at day 8 of regeneration. Unexpectedly, both V1-receptor and V2-receptor antagonists increased metaphase index at days 5 and 8 of regeneration. Neither AVP nor AVP-receptor antagonists affected plasma levels of corticosterone in rats bearing regenerating adrenals. It is concluded that AVP, acting via V1 receptors located in adrenals, exerts a stimulating effects on adrenal regeneration. Due to the down-regulation of V1-receptor expression in regenerating adrenals, this effect is very weak and is easily overcome by a tonic inhibitory action of endogenous AVP systems probably involving extra-adrenal indirect mechanisms.

Adrenal Cortex↗

PubMed2005

Adrenomedullin and vascular endothelium growth factor genes are overexpressed in the regenerating rat adrenal cortex, and AM and VEGF reciprocally enhance their mRNA expression in cultured rat adrenocortical cells.

Adrenomedullin (AM) is an endogenous regulatory peptide, which exerts growth promoting and neoangiogenic actions in several normal and neoplastic tissues. Evidence has been provided that AM and the pro-angiogenic peptide vascular endothelium growth factor (VEGF) are expressed in the adrenal gland, and we investigated whether their gene transcription is modified in a model of rapid rat adrenal growth, namely regeneration after enucleation and contralateral adrenalectomy. Real-time polymerase chain reaction (PCR) showed that AM and VEGF mRNAs were significantly increased in regenerating adrenals with respect to the intact adrenocortical tissue of sham-operated control rats. Subsequent studies were carried out on dispersed rat adrenocortical cells cultured in vitro for 72 h. Conventional PCR demonstrated that cultured cells expressed AM and VEGF mRNAs. Moreover, real-time PCR showed that 24 h exposure to 10-8 M AM or 50 ng/ml VEGF significantly raised the expression of VEGF and AM, respectively, without affecting that of their own mRNA, suggesting the occurence of autocrine-paracrine up-regulatory mechanisms. Taken together, our findings allow us to conceive that the coordinate up-regulation of AM and VEGF expression may favor cell proliferation and neoangiogenesis, thereby leading to a rapid restoration of morphology and function of regenerating adrenals.

Adrenal Cortex↗

PubMed2004

Ghrelin inhibits FGF-2-mediated angiogenesis in vitro and in vivo.

Recent evidence indicates that ghrelin, an endogenous ligand of the growth hormone secretagogue receptor (GHS-R), is highly expressed in the cardiovascular system, and in this study we addressed the possibility that ghrelin may affect angiogenesis in vitro and in vivo. Reverse transcription-polymerase chain reaction showed that human umbilical vein endothelial cells (HUVECs) express ghrelin and GHS-R mRNAs. Ghrelin inhibited FGF-2-induced proliferation of HUVECs cultured in vitro, the maximal effective concentration being 10(-8) M, and this effect was annulled by the GHS-R antagonist D-Lys3-growth hormone releasing peptide-6. FGF-2 stimulated HUVEC cultured on Matrigel to form capillary-like structures, and ghrelin (10(-8) M) suppressed this effect. In the chick embryo chorioallantoic membrane in vivo assay, FGF-2 induced a strong angiogenic response, which was counteracted by ghrelin (500 ng). Taken together, these findings suggest that ghrelin acts as an angiostatic molecule and indicate that its activity is comparable to that of a well-known angiostatic agent, i.e., vinblastine. The antiangiogenic activity of ghrelin deserves further investigations, alone or together with other antiangiogenic agents, for the treatment of pathological conditions characterized by enhanced angiogenesis.

Animals↗

PubMed2004

Growth hormone secretagogue receptor subtypes 1a and 1b are expressed in the human adrenal cortex.

Ghrelin is an endogenous ligand of the growth hormone secretagogue receptors (GHS-Rs), two subtypes of which have been recognized: the biologically active 1a and the biologically inactive 1b subtype. Reverse transcription-polymerase chain reaction demonstrated ghrelin and GHS-R1b mRNAs in eight human adrenal cortexes, and GHS-R1a mRNA only in six of the eight adrenal specimens. The GHS-R1a expression was absent in the two adrenal cortexes obtained from 76- and 79-year old male patients. Since previous studies showed that ghrelin does not affect steroid-hormone secretion, the present findings suggest that ghrelin via the GHS-R1a could be involved in the autocrine-paracrine control of human-adrenal growth.

Adrenal Cortex↗

PubMed2004

Beacon[47-73] inhibits glucocorticoid secretion and growth of cultured rat and human adrenocortical cells.

Evidence has been recently provided that beacon, an ubiquitin-like protein overexpressed in the hypothalamus of Israeli sand rat, is also expressed in several endocrine glands of the Wistar rat, including adrenal cortex. Moreover, it has been shown that the in vivo administration of beacon[47-73] (hereinafter, beacon) evokes within 60 min a marked decrease in the plasma concentrations of ACTH and corticosterone. Hence, we have investigated the effect of beacon (4x10(-9) or 4x10(-7) M) on the secretion and growth of cultured rat and human zona fasciculata/reticularis (ZF/R) cells. Reverse transcription-polymerase chain reaction detected beacon mRNA in all human adrenal cortexes examined. A 3-h exposure to beacon was ineffective, but prolonged (24 and 96 h) exposures significantly lowered basal corticosterone and cortisol secretion from cultured rat and human ZF/R cells, respectively. Moreover, beacon (4x10(-7) M) counteracted the secretagogue action of 10(-8) M ACTH on cultured cells. The 96-h exposure to beacon concentration-dependently decreased basal proliferation rate of cultured cells, without inducing significant changes in the number of apoptotic and necrotic cells. Beacon (4x10(-7) M) significantly inhibited the proliferogenic effect of 10(-8) M adrenomedullin. In light of the involvement of ubiquitin-like proteins in the control of cell cycle and protein sorting and degradation, the hypothesis is advanced that the inhibitory effect of beacon on the secretion and growth of cultured rat ZF/R cells may be connected to its stimulating effect on proteolysis of steroidogenic enzymes and proteins involved in cell replication.

Adrenal Cortex↗

PubMed2003

Influence of the Alu-repeat I/D polymorphism in t-PA gene intron 8 on the stimulated t-PA release after venous occlusion.

Tissue type plasminogen activator (t-PA) is released from endothelium in both a constitutive and regulated fashion. In healthy subjects, an association between net t-PA release rate and a few t-PA gene polymorphisms, including the Alu-repeat I/D polymorphism in intron 8, was described. The possible influence of the Alu-repeat polymorphism on t-PA release was evaluated after a venous occlusion test (VO) in 82 patients showing an impaired fibrinolytic capacity associated with different arterial disease or with previous venous thrombosis, and in 50 healthy controls. Euglobulin lysis time, t-PA antigen (t-PA:Ag) and activity, PAI-1 antigen and activity plasma levels were assayed before and 20 minutes after VO; the Alu-repeat I/D polymorphism was determined by PCR. Defective fibrinolysis was due to reduced t-PA release in 40 patients (t-PA group) and to PAI-1 excess in 42 patients (PAI group). No differences in both genotype distribution and allele frequencies were observed between patients and controls. The t-PA:Ag increase after VO (20/0-minute levels ratio adjusted for hematocrit) was considerably higher both in controls and in PAI group patients carrying the I allele than in the DD genotype carriers (II, ID, DD: 3.77+/-0.62, 3.43+/-0.44, 2.06+/-0.32 in controls, and 3.67+/-0.23, 2.80+/-0.50, 1.62+/-0.29 in PAI group, respectively). The difference was significant between the DD and both the ID and II genotypes in controls (p<0.05), and between the DD and II genotypes in PAI-1 group (p<0.05). A slight and nonsignificant trend of association between genotype and t-PA:Ag 20/0 ratio was seen in the t-PA group patients. In conclusion, these data suggest a possible genetic modulation of t-PA-regulated secretion.

Adult↗

PubMed2003

Adrenomedullin is expressed in cord blood hematopoietic cells and stimulates their clonal growth.

Adrenomedullin (AM) is a hypotensive peptide, which originates from the proteolytic cleavage of pro(p)AM and acts via AM22-52-sensitive receptors. Reverse transcription polymerase chain reaction allowed the detection of the specific mRNAs of pAM in the mononuclear hematopoietic cells of the cord blood and immunocytochemistry demonstrated their abundant AM-immunoreactivity. AM (10(-8) M) markedly enhanced clonal growth of cord blood hematopoietic cells cultured on semisolid media added with stem cell-growth promoting cytokines, and this effect was abolished by AM22-52 (10(-6) M). Collectively, these findings indicate that AM is expressed in and stimulates the proliferation of cord blood hematopoietic stem cells. Cord blood has been proposed as a source of stem cells alternative to bone marrow for allogeneic transplantation, and our study suggests that AM may be used, in addition to the classic cytokines, to expand in vitro cord blood stem cells in advance of their clinical use.

Adrenomedullin↗

PubMed2003

Human skin keratinocytes and fibroblasts express adrenomedullin and its receptors, and adrenomedullin enhances their growth in vitro by stimulating proliferation and inhibiting apoptosis.

Adrenomedullin (ADM) is a hypotensive peptide, which originates from the proteolytic cleavage of pro(p)ADM and acts via two subtypes of receptors, named L1-R (L1-R) and calcitonin-receptor-like receptor (CRLR). L1-R is selective for ADM depending on the expression of the subtype 1 or the subtypes 2 and 3 of a family of chaperones, called receptor-activity-modifying proteins (RAMPs). Compelling evidence indicates that ADM, in addition to regulating blood pressure and water and electrolyte balance, also exerts a major growth promoting action in several normal and neoplastic cells. Reverse transcription (RT)-polymerase chain reaction (PCR) allowed the detection of pADM, L1-R and CRLR mRNAs in cultured human skin keratinocytes and fibroblasts. RAMP1 and RAMP2 (but not RAMP3) mRNAs were present, but their level of expression was rather weak, thereby suggesting that L1-R is the main subtype of ADM receptor in both keratinocytes and fibroblasts. ADM concentration-dependently raised the proliferation rate and lowered the apoptotic rate of both keratinocytes and fibroblasts cultured in vitro, maximal effective concentration being 10(-8) M. The effects of 10(-8) M ADM was annulled by the putative ADM-receptor antagonist ADM22-52 (10(-6) M). ADM22-52 also lowered basal proliferative activity of keratinocytes and fibroblasts, without affecting their apoptotic deletion rate. Taken together, these findings allow us to conclude that i) human skin keratinocytes and fibroblasts express ADM and its receptors; and ii) endogenous ADM system promotes the growth of keratinocytes and fibroblasts cultured in vitro, by enhancing their proliferative activity and lowering their apoptotic deletion.

Adrenomedullin↗

PubMed2002

The effects of vitamin D receptor polymorphism on secondary hyperparathyroidism and bone density after renal transplantation.

Immunosuppresive treatment and secondary hyperparathyroidism (SHPT) are considered among the most important pathogenetic factors for postrenal transplant bone disease. The aim of this study was to investigate the relationships among vitamin D receptor (VDR) gene polymorphism, parathyroid hormone (PTH) levels, and bone density in renal transplant recipients. We enrolled 69 patients (47 men and 22 women; mean age, 47 +/- 11 years) who had undergone kidney transplantation 51 +/- 5 months before. All patients underwent an evaluation of the main biochemical parameters of bone metabolism as well as bone densitometry. VDR alleles were typed by a polymerase chain reaction (PCR) assay based on a polymorphic BsmI restriction site. When the patients were categorized according to the VDR genotype (BB, Bb, and bb), serum creatinine, and the cumulative doses of immunosuppressive drugs were similar across the groups. PTH levels higher than 80 pg/ml were found in 53.6% of the patients, with the highest values being detected in the bb VDR genotype (p < 0.05). PTH was significantly correlated to urinary type I collagen cross-linked N-telopeptide (NTx) values. Bone density was low in the whole population; however, spinal bone density was lower in the bb subgroup (p < 0.02). In the whole population, only PTH (p < 0.05) and body mass index (BMI; p < 0.01) were independent predictors of spinal bone density. When grouping the patients by the VDR gene polymorphism, only PTH continued to be an independent predictor of spinal bone density in the bb allele subgroup (R2 adj. = 0.17). We can conclude that the VDR genotype polymorphism affects bone density of renal transplant recipients via its effects on the severity of SHPT.

Absorptiometry, Photon↗

PubMed2002

Evidence for an autocrine-paracrine role of adrenomedullin in the cultured rat adrenal zona glomerulosa cells.

Rat adrenomedullin (ADM) is a 50-amino acid hypotensive and vasodilating peptide, which derives from the posttranslational proteolytic cleavage of pro(p)ADM. ADM acts via at least two subtypes of receptors, named L1-receptor (L1-R) and calcitonin receptor-like receptor (CRLR). CRLR functions as a calcitonin gene-related peptide or a selective ADM receptor depending on the expression of the subtype 1 or the subtypes 2 and 3 of a family of receptor-activity-modifying proteins (RAMPs). Adrenal zona glomerulosa (ZG) is one of the main target tissues of ADM, which has been shown to exert a potent inhibitory effect on aldosterone secretion acting through ADM[22-52]-sensitive receptors. Reverse transcription (RT)-polymerase chain reaction (PCR) consistently allowed the detection of pADM mRNA in the ZG, but not zona fasciculata-reticularis (ZF/R) cells of the rat adrenal cortex. Immunocytochemistry and radioimmune assay showed a weak but sizeable expression of ADM protein in the ZG, but not inner adrenocortical layers. ZG cells expressed peptidyl-glycine alpha-amidating monooxigenase, the enzyme converting immature ADM to the mature peptide, thereby suggesting their potential ability to produce active ADM. RT-PCR demonstrated the presence in ZG, but not ZF/R cells, of the specific mRNAs of L1-R, CRLR and RAMPs (especially RAMP2). ZG cells were cultured in vitro for 24 or 48 h in the presence of ADM (10(-8) M) and/or its receptor antagonist ADM[22-52] (10(-6) M). ADM increased proliferation index and lowered apoptotic index of cultured cells, and the effects were annulled by ADM[22-52]. ADM[22-52] alone was ineffective in 24 h cultures, but moderately decreased proliferation index and raised apoptotic index in 48 h cultures. In conclusion, our study provides evidence that i) rat ZG cells express ADM and ADM receptor of L1 and CRLR/RAMP2 subtypes, which both are sensitive to ADM[22-52]; and ii) endogenous ADM system modulates in an autocrine/paracrine manner ZG growth, by stimulating cell proliferation and reducing cell apoptotic deletion.

Adrenomedullin↗

PubMed2002

Attempt to improve the diagnosis of immune thrombocytopenia by combined use of two different platelet autoantibodies assays (PAIgG and MACE).

BACKGROUND AND OBJECTIVES: Despite an extensive search for a definitive diagnostic assay for platelet autoantibodies, the laboratory diagnosis of immune thrombocytopenia (ITP) still remains a clinical challenge. Data in the literature have so far demonstrated that measurement of platelet-associated IgG (PAIgG) is sensitive, especially when flow cytometry is employed, but lacks adequate specificity. Measuring specific autoantibodies by antigen capture techniques increases specificity, but a large part of patients escape autoantibodies detection by such means too. The aim of the present study was to compare the diagnostic value of PAIgG with a modified antigen capture ELISA (MACE) in patients with primary and secondary immune thrombocytopenia and in patients with non-immune thrombocytopenia. DESIGN AND METHODS: One hundred and four patients with a platelet count lower than 100x109/L were studied. Forty-two patients had primary ITP (P-ITP), 23 patients had ITP secondary to other immune diseases (S-ITP) and 39 patients had thrombocytopenia due to decreased platelet production (non-immune; NITP). PAIgG was measured by immunofluorescent flow cytometry, whereas specific platelet-associated autoantibodies (against GP IIb/IIIa, Ib/IX, Ia/Ia) were measured by a commercially available modified antigen capture assay (MACE, GTI, USA). RESULTS: The sensitivity of the PAIgG assay for ITP was 60%, the specificity was 77%, the positive predictive value was 81% and the negative predictive value was 54%. The sensitivity of MACE was 60%, specificity was 97%, the positive predictive value 97% and the negative predictive value 59%. We found a 73% concordance between PAIgG and MACE assays. Both PAIgG and MACE had significantly greater sensitivity in S-ITP than in P-ITP. INTERPRETATION AND CONCLUSIONS: Forty percent of patients with clinically diagnosed immune thrombocytopenia had no detectable platelet autoantibodies, possibly because of intrinsic methodological detection problems, different stages of disease, or absence of a true immune etiology.

Adult↗