Biomedical subjects

Luigi Giusto Spagnoli

Publications and source records attributed to Luigi Giusto Spagnoli.

At least 19 recordsLinked to original sources

PubMed2007

Persistent Chlamydia pneumoniae infection of cardiomyocytes is correlated with fatal myocardial infarction.

Acute myocardial infarction (AMI) associated with unfavorable prognosis is likely to be the consequence of a diffuse active chronic inflammatory process that destabilizes the whole coronary tree and myocardium, suggesting a possible common causal agent underlying both conditions. The main objective of this study was to investigate whether Chlamydia pneumoniae (CP) infection occurred beyond the coronary plaques, namely in the myocardium of individuals who died of AMI. The presence of CP cell wall antigen (OMP-2) and CP-HSP60 was investigated in the myocardium and coronary plaques of 10 AMI and 10 age-matched control patients by immunohistochemistry, electron microscopy, and molecular biology. OMP-2 antigens were found in the unaffected myocardium of 9 of 10 AMI patients. Conversely, only 1 of 10 control patients exhibited a positive staining for CP. Moreover, OMP-2 and CP-HSP60 were detected in the whole coronary tree. CP presence was strongly associated with a T-cell inflammatory infiltrate. Our results suggest that CP may underlie both coronary and myocardial vulnerabilities in patients who died of AMI and corroborate the notion that CP may act by reducing cardiac reserves, thus worsening the ischemic burden of myocardium.

Acute Disease↗

PubMed2006

Propionyl-L-carnitine reduces proliferation and potentiates Bax-related apoptosis of aortic intimal smooth muscle cells by modulating nuclear factor-kappaB activity.

Propionyl-l-carnitine (PLC) has been introduced among the therapeutic approaches of peripheral arterial disease, and more recently, an increase of intimal cell apoptosis has been demonstrated to contribute to its effectiveness in rabbit carotid postinjury myointimal hyperplasia prevention. How PLC mediates these effects on vascular smooth muscle cells (SMCs) remains poorly understood. We investigated the role of NF-kappaB in PLC-induced arterial remodeling. In vivo, daily PLC treatment 15 days after injury resulted in a reduction of relative rat aortic intimal volume, an increase of apoptosis, Bax up-regulation without changing the Bcl-2 level, and a reduction of NF-kappaB, vascular cell adhesion molecule-1, monocyte chemotactic protein-1, and survivin in myointimal thickening compared with controls. In the presence of 10% serum, a reduced G(1) --> S phase progression preceded PLC-induced intimal cell apoptosis; in 0.1% serum cultures, in a dose-dependent manner, PLC rapidly induced intimal cell apoptosis and reduced p65, p50, IAP-1, and IAP-2 expression. Inhibiting NF-kappaB activation through SN50 increased apoptotic rate and Bax expression in intimal but not in medial SMCs, and successive PLC treatment failed to induce a further increase in apoptotic rate. Bax antisense oligodeoxynucleotide reduced PLC-induced intimal cell apoptosis and cytochrome c release. The PLC-induced attenuation of NF-kappaB activity in intimal cells was also due to the increase of IkappaB-alpha bioavailability, as the result of a parallel induction of IkappaB-alpha synthesis and reduction of phosphorylation and degradation. Collectively, these findings document that NF-kappaB activity inhibition contributes to PLC-induced proliferative arrest and Bax-related apoptosis of intimal SMCs.

Animals↗

PubMed2006

Pregnancy-associated plasma protein-a is markedly expressed by monocyte-macrophage cells in vulnerable and ruptured carotid atherosclerotic plaques: a link between inflammation and cerebrovascular events.

OBJECTIVES: The study aim was to evaluate serologic expression of pregnancy-associated protein-A (PAPP-A) in patients affected by cerebrovascular accidents and to correlate it with histopathologic carotid plaque complexity. BACKGROUND: Little is known about PAPP-A expression in carotid atherosclerotic disease and whether this protein represents a marker of plaque vulnerability also in carotid district. METHODS: Seventy-two carotid plaques from patients submitted to surgical endarterectomy (19 who suffered a major stroke, 24 transient ischemic attack, and 29 asymptomatic) were evaluated. Serologic PAPP-A levels were determined by enzyme-linked immunoadsorbent assay. Plaques were divided in three groups based on histology: 1) stable (n = 38); 2) vulnerable (n = 13); 3) ruptured with thrombus (n = 14). Immunohistochemical staining for PAPP-A, smooth muscle cells, macrophages, and T-lymphocytes was performed in all cases. Real-time polymerase chain reaction assessed local PAPP-A production, and double immunofluorescence confocal microscopy (ICM) characterized cell type expressing PAPP-A. RESULTS: Pregnancy-associated protein-A (serologic values were 4.02 +/- 0.18 mIU/l in Group 1, 7.43 +/- 0.97 mIU/l in Group 2, and 6.97 +/- 0.75 mIU/l in Group 3 [1 vs. 3, p = 0.01; 1 vs. 2, p = 0.004; 2 vs. 3, p = 0.71, respectively]). Pregnancy-associated protein-A (expression showed a mean score value of 0.62 +/- 0.06 for stable plaques, 2.54 +/- 0.14 for vulnerable plaques, and 2.71 +/- 0.12 for ruptured plaques [1 vs. 2, p = 0.001; 1 vs. 3, p = 0.001; 2 vs. 3, p = 0.37, respectively]). Real-time polymerase chain reaction demonstrated local messenger ribonucleic acid PAPP-A production, and double ICM confirmed monocyte/macrophage expression of PAPP-A in Groups 2 and 3 but not Group 1. CONCLUSIONS: This study suggests that PAPP-A is a marker of carotid plaque destabilization and rupture. Further studies are necessary to determine if PAPP-A can represents a new target for stratifying the risk of cerebrovascular events.

Aged↗

PubMed2006

Aging, smooth muscle cells and vascular pathobiology: implications for atherosclerosis.

Epidemiological and autopsy studies suggest a close link between aging and the clinical manifestation of atherosclerosis. Several experiments show increased arterial susceptibility to atherogenetic stimuli in aged subjects. All together, these findings support the concept that aging represents an independent atherogenetic risk factor, intimately associated to other parietal, microenvironmental and systemic noxae. Smooth muscle cells (SMCs) represent the major arterial cell population. As aging occurs, SMCs progressively migrate from the tunica media and accumulate into the tunica intima. Myointimal thickening may represent the site where low-grade atherogenic stimuli cause early development and more severe lesion progression. Intimal SMC accumulation is characterized from a switch, from a differentiated to a synthetic phenotype, with reduced myocytic cytoskeletal markers and the expression of new proteins. Aging also associates to changes of SMC proliferative and apoptotic behavior and response to growth factors, such as transforming growth factor-beta1. The alteration of SMC properties represents a crucial event in the pathobiology of arterial wall, since it contributes to the vascular remodeling and decline of function with aging and favors the progression of atherosclerosis. Increased knowledge of biomolecular mechanisms regulating these events helps to develop new strategies aimed at contrasting the adverse effect of vascular aging.

Aging↗

PubMed2006

Protease-activated receptor-2 activation in gastric cancer cells promotes epidermal growth factor receptor trans-activation and proliferation.

Dysregulated epidermal growth factor receptor (EGFR) signaling is involved in gastric cancer (GC) cell growth. However, the mechanism that sustains EGFR signaling in GC remains unknown. Since protease-activated receptor-2 (PAR-2), a G protein-coupled receptor, has been shown to trans-activate EGFR in several cell types, we examined the role of PAR-2 in GC. We show here that in vitro activation of PAR-2 enhances the growth of two GC cell lines, AGS and MKN28. In both these cell lines, PAR-2 trans-activated EGFR and inhibition of EGFR tyrosine kinase activity by AG1478 or specific EGFR siRNA completely prevented PAR-2-driven proliferation. Antibody blockade of EGF-like ligands to EGFR did not modify EGFR signaling or cell growth induced by PAR-2 activation. In contrast, PAR-2 promoted Src activation and interaction of this kinase with EGFR. In support of this, inhibition of Src kinase activity by PP1 or siRNA blocked PAR-2-induced EGFR signaling cascade and cell growth. Finally, PAR-2 was detectable in both normal and GC specimens, but its expression was more pronounced in GC than controls and correlated with activated EGFR. These data show that PAR-2 is overexpressed in GC and suggest a role of PAR-2 in EGFR trans-activation and cell growth.

Adenocarcinoma↗

PubMed2005

Phenotypic heterogeneity influences the behavior of rat aortic smooth muscle cells in collagen lattice.

Phenotypic modulation of vascular smooth muscle cells (SMCs) in atherosclerosis and restenosis involves responses to the surrounding microenvironment. SMCs obtained by enzymatic digestion from tunica media of newborn, young adult (YA) and old rats and from the thickened intima (TI) and underlying media of young adult rat aortas 15 days after ballooning were entrapped in floating populated collagen lattice (PCL). TI-SMCs elongated but were poor at PCL contraction and remodeling and expressed less alpha2 integrin compared to other SMCs that appeared more dendritic. During early phases of PCL contraction, SMCs showed a marked decrease in the expression of alpha-smooth muscle actin and myosin. SMCs other than TI-SMCs required 7 days to re-express alpha-smooth muscle actin and myosin. Only TI-SMCs in PCL were able to divide in 48 h, with a greater proportion in S and G2-M cell cycle phases compared to other SMCs. Anti-alpha2 integrin antibody markedly inhibited contraction but not proliferation in YA-SMC-PLCs; anti-alpha1 and anti-alpha2 integrin antibodies induced a similar slight inhibition in TI-SMC-PCLs. Finally, TI-SMCs rapidly migrated from PCL on plastic reacquiring their epithelioid phenotype. Heterogeneity in proliferation and cytoskeleton as well the capacity to remodel the extracellular matrix are maintained, when SMCs are suspended in PCLs.

Actins↗

PubMed2005

Diffuse and active inflammation occurs in both vulnerable and stable plaques of the entire coronary tree: a histopathologic study of patients dying of acute myocardial infarction.

OBJECTIVES: This study was undertaken to define and compare geographic coronary artery inflammation in patients who were dying of acute myocardial infarction (AMI), chronic stable angina (SA), and noncardiac causes (CTRL). BACKGROUND: Biochemical markers and flow cytometry provide indirect evidence of diffuse coronary inflammation in patients dying of acute coronary syndromes. Yet no histopathologic studies have corroborated these findings. A key unanswered question is whether the inflammatory burden involves the entire coronary tree or is limited to a few plaques. METHODS: We examined 544 coronary artery segments from 16 patients with AMI, 109 segments from 5 patients with SA, and 304 coronary segments from 9 patients with CTRL. RESULTS: An average of 6.8 +/- 0.5 vulnerable segments per patient were found in the AMI group (in addition to culprit lesions) compared with an average of 0.8 +/- 0.3 and 1.4 +/- 0.3 vulnerable lesions/patient in the SA and CTRL groups, respectively. The AMI group, independent of the type of plaque observed, showed significantly more inflammatory infiltrates compared with the SA and CTRL groups (121.6 +/- 12.4 cell x mm2 vs. 37.3 +/- 11.9 cell x mm2 vs. 26.6 +/- 6.8 cell x mm2, p = 0.0001). In AMI patients, active inflammation was not only evident within the culprit lesion and vulnerable plaques but also involved stable plaques. These showed a three- to four-fold higher inflammation than vulnerable and stable plaques from the SA and CTRL groups, respectively. CONCLUSIONS: This histopathologic study found that both vulnerable and stable coronary plaques of patients dying of AMI are diffusely infiltrated by inflammatory cells.

Aged↗

PubMed2005

Extracellular proteases in atherosclerosis and restenosis.

Extracellular proteolysis plays a key role in many pathophysiologic processes including cancer, inflammatory diseases, and cardiovascular conditions such as atherosclerosis and restenosis. Whereas matrix metalloproteinases are their best known member, many others are becoming better known. The extracellular proteases are a complex and heterogeneous superfamily of enzymes. They include metalloproteinases (matrix metalloproteinases, adamalysins, or pappalysins), serine proteases (elastase, coagulation factors, plasmin, tissue plasminogen activator, urokinase plasminogen activator), and the cysteine proteases (such cathepsins). In addition to their matrix degradation capabilities, they have other less well known biologic functions that include angiogenesis, growth factor bioavailability, cytokine modulation, receptor shedding, enhancing cell migration, proliferation, invasion, and apoptosis. This review discusses extracellular proteases relevant to the vasculature, their classification and function, and how protease disorders contribute to arterial plaque growth, including chronic atherosclerosis, acute coronary syndromes, restenosis, and vascular remodeling. These broad extracellular protease functions make them potentially interesting therapeutic targets.

Animals↗

PubMed2005

Increased expression and activity of matrix metalloproteinases characterize embolic cardiac myxomas.

Tumor embolism occurs in 30 to 50% of all cases of cardiac myxoma, but the causes are still uncertain. Matrix metalloproteinases (MMPs) are proteolytic enzymes that degrade the extracellular matrix (ECM) and play a crucial role in plaque instability and aortic aneurysm development, in addition to cancer and heart failure. To determine whether MMP activity contributes to tumor embolism, we examined 27 left atrium-sided myxomas, 10 of which showed clinical signs of peripheral embolism. Immunohistochemistry (in all cases) and Western blotting, and in situ and in-gel zymography (in four embolic and six nonembolic consecutive tumors) demonstrated higher expression and activity of MT1-MMP, pro-MMP-2, and pro-MMP-9 in embolic myxomas, whereas pro-MMP-1, MMP-3, and TIMP-1 levels were similar to those of nonembolic tumors. Reverse transcriptase-polymerase chain reaction demonstrated that increased MMP activity was due, at least in part, to increased transcription and that TIMP-2 transcripts increased in embolic myxomas. In vitro, embolic tumor cells retained higher MT1-MMP and pro-MMP-2 levels in basal conditions and after stimulation with interleukin-1beta and interleukin-6. Increased MMP synthesis and release correlated with enhanced ECM degradation products containing glycosaminoglycan chains in embolic myxoma tissue. Our results strongly suggest that MMP overexpression may contribute to an excessive degradation of tumor ECM and increase the risk of embolism in cardiac myxomas.

Adult↗

PubMed2004

Modulation of clusterin isoforms is associated with all-trans retinoic acid-induced proliferative arrest and apoptosis of intimal smooth muscle cells.

OBJECTIVE: Clusterin is a heterodimeric glycoprotein which is implicated in several biological processes. The nuclear (n-CLU) and cytoplasmic secreted (s-CLU) isoforms have recently been described, but their role is still unclear. The aim of this study is to investigate the expression of clusterin and its isoforms during proliferative arrest and apoptosis of vascular smooth muscle cells (SMCs). METHODS AND RESULTS: Clusterin expression was evaluated by immunohistochemistry and Western blotting in human arteries and rat aortas. In human diffuse myointimal thickening, clusterin was detected in cell cytoplasm and extracellular space, whereas it was practically absent in the media. In rat aortas 15 days after ballooning, intimal cells (IT cells) overexpressed s-CLU and n-CLU, the latter mainly in the inner neointima; clusterin expression decreased at 60 days. In vitro, IT cells maintained high clusterin expression and its antisense markedly reduced proliferation and increased apoptosis. Western blotting showed that all-trans retinoic acid-induced proliferative arrest and increased alpha-smooth muscle actin expression did associate to s-CLU and B-myb reduction, whereas bax-related apoptosis was associated to a shift from the s-CLU to n-CLU isoform. CONCLUSIONS: Clusterin overexpression characterized neointimal SMCs; s-CLU expression decreased in IT cells during all-trans retinoic acid-induced proliferative arrest and redifferentiation, whereas n-CLU overexpression was characteristic of apoptosis. Clusterin was detected in human arterial myointimal thickening and absent in the underlying media. Rat neointimal cells overexpressed clusterin and clusterin antisense oligonucleotide reduced proliferation and increased apoptosis. All-trans retinoic acid-induced proliferative arrest showed association with s-CLU reduction and n-CLU overexpression with apoptosis, supporting a different biological role of these isoforms.

Animals↗

PubMed2004

Role of ageing and coronary atherosclerosis in the development of cardiac fibrosis in the rabbit.

OBJECTIVE: Myocardial fibrosis contributes to the impairing of cardiac function and characterizes ageing, but is also a consequence of atherosclerotic ischemic disease. Since atherosclerosis is a slow progressive disease, which prevails in elderly populations, the aim of this study was to distinguish the contribution of ageing and atherosclerosis to cardiac fibrosis. METHODS: Coronary atherosclerosis was induced in 5-6-year-old rabbits by a hyperlipemic diet for 9 months. Left ventricular (LV) collagen was quantified by densitometric analysis after Sirius-Red staining; an immunohistochemical investigation of the interstitium was also performed. RESULTS: Atherosclerosis was associated to a marked increase of left ventricular interstitial collagen with the appearance of fibrotic foci and a decrease of coronary vessel endothelial nitric oxide synthase (eNOS) expression. In fibrotic foci, abundant macrophages co-localized with transforming growth factor beta-1 (TGFbeta-1)-positive myofibroblasts and vascular cell adhesion molecule-1 (VCAM-1) positive microvessels (52.3+/-3.9%). In normocholesterolemic rabbits, ageing resulted in a fourfold increase of myocardial interstitial collagen, with alpha-smooth muscle actin and TGFbeta-1 negative fibroblasts and VCAM-1 positive microvessels (19.4+/-1.2%) without macrophages, suggesting a role of endothelial dysfunction in age-related fibrosis. CONCLUSIONS: There is a distinct difference between ageing and coronary atherosclerosis-induced cardiac fibrosis, although the effects may be cumulative. In the cascade of events leading to myocardial remodeling, reparative fibrosis with TGFbeta-1-positive myofibroblasts and interstitial inflammation were the major findings in atherosclerotic old rabbits, whereas with ageing alone, interstitial fibrosis with TGFbeta-1 negative fibroblasts and VCAM-1 positive microvessels prevailed.

Actins↗

PubMed2004

Extracranial thrombotically active carotid plaque as a risk factor for ischemic stroke.

CONTEXT: Recent studies suggest that factors other than the degree of carotid stenosis are involved in ischemic stroke pathogenesis, especially modifications of plaque composition and related complications. OBJECTIVE: To examine the role of carotid plaque rupture and thrombosis in ischemic stroke pathogenesis in patients undergoing carotid endarterectomy, excluding those with possible cardiac embolization or with severe stenosis of the circle of Willis. DESIGN, SETTING, AND PATIENTS: A total of 269 carotid plaques selected from an Interinstitutional Carotid Tissue Bank were studied by histology after surgical endarterectomy between January 1995 and December 2002. A total of 96 plaques were from patients with ipsilateral major stroke, 91 plaques from patients with transient ischemic attack (TIA), and 82 plaques from patients without symptoms. MAIN OUTCOME MEASURES: Differences in the frequency of thrombosis, cap rupture, cap erosion, inflammatory infiltrate, and major cardiovascular risk factors between study groups. RESULTS: A thrombotically active carotid plaque associated with high inflammatory infiltrate was observed in 71 (74.0%) of 96 patients with ipsilateral major stroke (and in all 32 plaques from patients operated within 2 months of symptom onset) compared with 32 (35.2%) of 91 patients with TIA (P < .001) or 12 (14.6%) of 82 patients who were without symptoms (P < .001). In addition, a fresh thrombus was observed in 53.8% of patients with stroke operated 13 to 24 months after the cerebrovascular event. An acute thrombus was associated with cap rupture in 64 (90.1%) of 71 thrombosed plaques from patients with stroke and with cap erosion in the remaining 7 cases (9.9%). Ruptured plaques of patients affected by stroke were characterized by the presence of a more severe inflammatory infiltrate, constituted by monocytes, macrophages, and T lymphocyte cells compared with that observed in the TIA and asymptomatic groups (P = .001). There was no significant difference between groups in major cardiovascular risk factors. CONCLUSION: These results demonstrate a major role of carotid thrombosis and inflammation in ischemic stroke in patients affected by carotid atherosclerotic disease.

Aged↗

PubMed2004

Modulation of different clusterin isoforms in human colon tumorigenesis.

Clusterin is a ubiquitous secretory heterodimeric disulfide-linked glycoprotein, which is implicated in several physiological processes, including immune regulation, cell adhesion and morphological transformation, lipid transportation, tissue remodelling, membrane recycling and cell-cell interactions. A large number of studies have focused their interest on clusterin gene products as mediators of cell cycle progression and cell death induction, although data on the different isoforms and their role in the different cell processes are still obscure. Recently, an increased clusterin expression in breast cancer has been reported. In order to elucidate the role of clusterin in tumor progression and whether one of its isoforms is preferentially expressed in tumorigenesis, we examined its presence throughout the different steps of human colon carcinoma, one of the best-characterized models of human tumor progression. The immunohistochemical observation of 30 bioptic and surgical colon specimens demonstrated a cell compartment clusterin translocation from the nucleus to the cytoplasm directly related to tumor progression. In fact, a nuclear localization found in healthy colonic mucosa is consistent with the involvement of the proapoptotic nuclear form in the regulation of cell cycle progression and in cell death induction. The progression towards high-grade and metastatic carcinoma leads to cytoplasmic clusterin distribution. Protein extracts from freshly isolated cells of the same patients confirm in high-grade carcinomas with metastatic nodes the complete loss of the proapoptotic nuclear form and a cytoplasmic overexpression of the highly glycosylated form. Data obtained from in vitro experiments confirm that this form is released in the extracellular space and corresponded to the fully glycosylated one. These data suggest that the controversial data on clusterin function in tumors may be related to the pattern shift of its isoform production. As the secreted form of clusterin is correlated to cell matrix formation, cell membrane remodeling and cell-cell adhesion, the overexpression of this form in highly aggressive tumors and metastatic nodes could be a potential new prognostic and predictive marker for colon carcinoma aggressiveness.

Blotting, Western↗

PubMed2004

Expression analysis of the gene encoding for the U-box-type ubiquitin ligase UBE4A in human tissues.

The Ubiquitination Factor E4A gene (UBE4A) encodes for a U-box-type ubiquitin ligase, originally described as an E4 ubiquitination factor. UBE4A is a mammalian homolog of Saccharomyces cerevisiae Ufd2. The UBE4A gene has been mapped on the human chromosome region 11q23.3, a critical region involved in some specific cancers such as neuroblastoma. Northern blots analysis on foetal and adult human tissues revealed a single band of approximately 7.5 kb transcript most abundant in the heart, skeletal muscle and kidney. We generated a polyclonal antibody to UBE4A and performed immunoblot and immunohistochemical analysis. The UBE4A protein appeared as a single band of approximately 125 kDa. UBE4A was present in the skeletal muscle, kidney and liver; a faint band was visible in peripheral blood leukocytes and spleen. We did not reveal expression of UBE4A in whole brain, colon, lung and heart. At the cellular level, UBE4A results predominantly expressed in the nucleus and the cytoplasm of cortical neurons and liver and in the nucleus of tubular kidney cells. In the liver, the nucleus of similar cells appeared to be unstained or stained at different levels suggesting that UBE4A may have a cell cycle dependent expression or a role of in cell cycle control. In conclusion, our results show that UBE4A is expressed in different tissues in a pattern that seems to be dependent from cell type and cell cycle and that UBE4A might have a specific role in different biochemical processes other than ubiquitination, including growth or differentiation.

Blotting, Northern↗

PubMed2004

Induction and regulation of Smad7 in the gastric mucosa of patients with Helicobacter pylori infection.

BACKGROUND & AIMS: Helicobacter pylori (Hp) infection causes a chronic gastric inflammation, which can lead to peptic ulceration and cancer. The inflammatory response is multifactorial and is characterized by exaggerated Th1 cytokine production. How the Th1 response is induced and maintained in the stomach of Hp-infected patients remains unclear. Transforming growth factor (TGF)-beta 1 negatively regulates Th1 cell development, and TGF-beta 1-deficient mice spontaneously develop gastritis. Here, we examined TGF-beta 1 signaling in Hp-associated gastritis. METHODS: Gastric biopsy specimens taken from patients with or without Hp infection were analyzed for the content of activated TGF-beta1 by ELISA and Smad3 and 7 expression by Western blotting. Induction of Smad7 by interferon (IFN)-gamma was examined in normal gastric mucosal biopsy specimens, whereas the effect of Smad7 inhibition on the ongoing Th1 response was analyzed in Hp-colonized biopsy specimens. RESULTS: Activated TGF-beta 1 was abundant in the mucosa of controls and Hp-infected patients, with no significant difference between the 2 groups. Despite this, in whole biopsy specimens and isolated mucosal cells from Hp-infected patients, there was defective TGF-beta 1-associated Smad3 phosphorylation, which was associated with high expression of the inhibitor Smad7. Blocking Smad7 with antisense oligonucleotides restored TGF-beta 1 signaling in biopsy specimens from Hp-infected patients and concomitantly reduced interferon-gamma and T-bet. Smad7 was inducible in normal gastric biopsy specimens by interferon-gamma through a STAT1-dependent mechanism, and neutralization of interferon-gamma in biopsy specimens from Hp-infected patients reduced Smad7 expression. CONCLUSIONS: These data suggest that, in Hp-infected gastric mucosa, interferon-gamma induces the expression of Smad7, which then prevents endogenous TGF-beta 1 from down-regulating the ongoing tissue-damaging Th1 response.

Adult↗

PubMed2004

Evidence of increased apoptosis and reduced proliferation in basal cell carcinomas treated with tazarotene.

A preliminary clinical experience suggested tazarotene, a new acetylenic retinoid, as an effective alternative topical treatment of basal cell carcinomas (BCC). The mechanisms of action of this synthetic retinoid, however, have not been yet clarified. In this work we assessed the in vivo effects of daily application of tazarotene for 24 wk, on 30 small superficial and nodular BCC, and the in vitro effects of tazarotene on immortalized basal and squamous tumor epidermal cells. Cellular proliferation, apoptosis and changes in expression of retinol and retinoic acid receptors (RAR), p53, bcl-2, and bax were studied by immunohistochemistry, western blotting and PCR. Overall, 76.7% of treated tumors showed >50% regression. Complete healing was observed in 46.7% of all treated BCC, without recurrences at 2-y observation. Regression was associated with reduced proliferation and increased apoptosis, demonstrated by Ki-67- and TdT-mediated dUTP-biotin nick-end labelling-positive nuclear staining, and with enhanced RAR-beta and bax expression, with RAR-alpha and -gamma expression unchanged. In vitro, tazarotene induced a concentration-dependent increase of RAR-beta and bax associated with a greater rate of apoptosis and growth inhibition in basaloid tumor cells compared with squamous tumor cells. Our studies provide convincing evidence that tazarotene induces BCC regression possibly by synergistic RAR-beta-dependent anti-proliferative and pro-apoptotic pathways.

Adult↗

PubMed2003

Alpha-actin isoform distribution in normal and failing human heart: a morphological, morphometric, and biochemical study.

We investigated the distribution of alpha-skeletal, alpha-cardiac, and alpha-smooth muscle actin isoforms in human heart during development, hypertrophy, and failure. At 20 weeks of fetal life, alpha-skeletal actin was localized in a small proportion of subendocardial and papillary muscle cardiomyocytes. At this gestation time, diffuse alpha-cardiac actin staining was observed, associated with focal expression of alpha-smooth muscle actin. In normal adult subjects, alpha-skeletal actin positive cardiomyocytes were distributed in a transmural gradient with the highest proportion located subendocardially. In myocardial hypertrophy and cardiomyopathies, the amount of alpha-skeletal actin was increased and diffuse staining was seen in all layers of ventricular myocardium, with the exception of idiopathic dilated cardiomyopathies. Cardiomyocytes were negative for alpha-smooth muscle actin in all pathological situations studied. As expected, fibroblasts in post-infarct scars expressed alpha-smooth muscle actin and transforming growth factor-beta1 but, surprisingly, were negative for these proteins in interstitial fibrosis. Our results demonstrate that increased expression of alpha-skeletal actin in the diseased human heart is associated with increased myocyte stretch, increased wall stress, and pressure overload, but not with idiopathic dilated cardiomyopathies. They also suggest that fibrotic changes develop with different mechanisms in scars versus interstitial fibrosis.

Actins↗

PubMed2003

[Unstable carotid plaque: biochemical and cellular marker of vulnerability].

Stroke is the second most common cause of death in developed countries. Carotid plaque disruption and distal embolization of atheromatous debris are the most common pathogenic mechanisms for cerebral ischemia from carotid atherosclerotic disease. Morphologic composition of the atherosclerotic plaque, rather than the stenotic severity, appears to be central in determining the risk of both plaque rupture and subsequent thrombosis. Histologic features of vulnerable plaques include a large lipid core, a thin fibrous cap, intraplaque hemorrhage, and an increased number of inflammatory cells, mostly monocyte-macrophages. Due to the catastrophic implications of thrombus formation and embolization on the arterial plaque, detection before major neurologic events occur is now a major goal of cardiovascular clinicians and researchers. New detection imaging techniques such as intravascular thermography, optical coherence tomography, photonic spectroscopy, and elastography have been developed in order to document atherosclerotic lesion composition. This review will focus on the new possibilities under investigation for vulnerable atherosclerotic carotid plaque detection by means of the serologic markers of plaque instability. New markers, such as pregnancy-associated protein A, P-selectin, interleukin-6 and interleukin-12, metalloproteinases, lipoprotein(a), and oxidation products have been reviewed. Most of the promising serologic markers in this article are still in a nascent phase of development and remain to be validated in clinical settings. However, these biohumoral markers, and their potential combination of techniques, may hold promise for the future characterization of the vulnerable plaque and moreover of the vulnerable patient.

Biomarkers↗