Biomedical subjects

Filomena de Nigris

Publications and source records attributed to Filomena de Nigris.

25 records · Page 2Linked to original sources

PubMed2003

Glycoxidation of low-density lipoprotein increases TUNEL positivity and CPP32 activation in human coronary cells.

Apoptosis of arterial cells induced by oxidized low-density lipoprotein (oxLDL) is thought to contribute to the progression of vascular dysfunction and atherogenesis. It is well established that diabetes mellitus is accompanied by both glycosylation and oxidation of LDL (glc-oxLDL), but the biological effects of these modified lipoproteins are poorly understood. We demonstrate here for the first time that glc-oxLDL increases TUNEL positivity and caspase-3 activation (by Western blot and immunocytochemistry) of human coronary smooth muscle cells. Overall, these effects induced by glc-oxLDL were greater than those achieved with oxLDL. Thus, glc-oxLDL activated downstream apoptotic signaling. This may influence the evolution of atherogenesis and vascular complications in diabetes.

Apoptosis↗

PubMed2002

Glycoxidized low-density lipoprotein downregulates endothelial nitricoxide synthase in human coronary cells.

OBJECTIVES: We examined the hypothesis that low-density lipoprotein (LDL) that is both oxidized and glycosylated potently downregulates the expression of endothelial nitric oxide synthase III (NOSIII) in human coronary endothelial cells. BACKGROUND: Diabetes mellitus is accompanied by both oxidation and glycosylation of LDL, but the potential interaction of these processes or the pathophysiologic effects of these modified lipoproteins on arteries are poorly understood. METHODS: Low-density lipoprotein was glycoxidized in vitro, and Western and Northern blot analyses were used to investigate NOSIII expression in human coronary endothelial cells. Nitric oxide (NO) bioactivity was represented by both basal and bradykinin-stimulated cellular cyclic guanosine monophosphate accumulation and L-citrulline conversion from L-arginine. Nuclear run-on experiments were performed to study the transcription rate of nascent NOSIII messenger ribonucleic acid (mRNA). RESULTS: Data showed a significant decrease in NOSIII expression after 24-h treatment with glycosylated low-density lipoprotein (glycLDL) and oxidized low-density lipoprotein (oxLDL). Accordingly, we observed a significant dose-dependent reduction in NO bioactivity (p < 0.05 to p < 0.001 vs. untreated cells, native low density lipoprotein [nLDL], glycLDL, and oxLDL). Glyc-oxLDL did not reduce the half-life of NOSIII mRNA or significantly enhance L-citrulline conversion. Nuclear run-on experiments showed that high doses of glyc-oxLDL can reduce the transcription rate of nascent NOSIII mRNA (densitometric analysis revealed a reduction of 25% [p < 0.05 vs. untreated cells, nLDL, and glycLDL] after treatment of cells with 300 microg/ml glyc-oxLDL). The effects of glyc-oxLDL are not related to the higher levels of oxidative compounds in comparison to those of oxLDL. CONCLUSIONS: These results indicate that glyc-oxLDL, per se, may influence signal transduction pathways involving NO-mediated regulatory signals and NOSIII activity in human endothelial cells. This phenomenon can adversely influence the evolution of clinical vascular complications, coronary heart disease, and atherogenesis in diabetic patients.

Blotting, Northern↗

PubMed2002

Maternal hypercholesterolemia during pregnancy promotes early atherogenesis in LDL receptor-deficient mice and alters aortic gene expression determined by microarray.

BACKGROUND: Maternal hypercholesterolemia during pregnancy is associated with markedly enhanced fatty streak formation in human fetal aortas and accelerated progression of atherosclerosis in normocholesterolemic children. METHODS AND RESULTS: To establish the causal role of maternal hypercholesterolemia in a genetically homogeneous murine model and to test the hypothesis that pathogenic events during fetal development result in persistent changes in arterial gene expression, female LDL receptor-deficient (LDLR(-/-)) mice were fed regular chow or high-fat diets supplemented with 0.075% or 1.25% cholesterol during pregnancy. Lesion sizes were determined in the aortic origin of their chow-fed offspring at 3 months. Maternal hypercholesterolemia more than doubled lesion sizes in male offspring (P<0.0001 for the 0.0075% cholesterol group). Microarray analysis of the expression of 11 000 murine genes in the nonatherosclerotic descending aorta by Affymetrix gene chips suggested that 139 genes were significantly regulated in offspring of hypercholesterolemic mothers. A subset of 12 of the upregulated transcripts was subjected to secondary analysis by semiquantitative PCR of pooled RNA and 4 genes were found to be upregulated >1.7-fold. Quantitative PCR for one of these genes using RNA from individual mice yielded similar results. Comparative immunostaining for several of the above genes also indicated increased protein content in offspring of hypercholesterolemic mothers. CONCLUSIONS: These findings establish an atherogenic effect of maternal hypercholesterolemia in genetically uniform mice and indicate that changes in aortic gene expression persist long after fetal exposure to hypercholesterolemia. In addition to elucidating pathogenic mechanisms initiated during fetal development, this approach may identify genes in morphologically normal arteries that influence the susceptibility to classical risk factors of atherosclerosis.

Animals↗

PubMed2002

Efficacy and age-related effects of nitric oxide-releasing aspirin on experimental restenosis.

Restenosis after percutaneous transluminal coronary angioplasty is caused by neointimal hyperplasia, which involves impairment of nitric oxide (NO)-dependent pathways, and may be further exacerbated by a concomitant aging process. We compared the effects of NO-releasing-aspirin (NCX-4016) and aspirin (ASA) on experimental restenosis in both adult and elderly rats. Moreover, to ascertain the efficacy of NCX-4016 during vascular aging, we fully characterized the release of bioactive NO by the drug. Sprague-Dawley rats aged 6 and 24 months were treated with NO releasing-aspirin (55 mg/kg) or ASA (30 mg/kg) for 7 days before and 21 days after standard carotid balloon injury. Histological examination and immunohistochemical double-staining were used to evaluate restenosis. Plasma nitrite and nitrate and S-nitrosothiols were determined by a chemiluminescence-based assay. Electron spin resonance was used for determining nitrosylhemoglobin. Treatment of aged rats with NCX-4016 was associated with increased bioactive NO, compared with ASA. NO aspirin, but not ASA, reduced experimental restenosis in old rats, an effect associated with reduced vascular smooth muscle cell proliferation. NCX-4016, but not ASA, was well tolerated and virtually devoid of gastric damage in either adult or old rats. Thus, impairment of NO-dependent mechanisms may be involved in the development of restenosis in old rats. We suggest that an NCX-4016 derivative could be an effective drug in reducing restenosis, especially in the presence of aging and/or gastrointestinal damage.

Aging↗

PubMed2002

New insights in the transcriptional activity and coregulator molecules in the arterial wall.

A number of vascular diseases are associated with abnormal expression of genes that contribute to their pathophysiological and clinical manifestations, but at the same time offer potential therapeutic targets. One of the promising therapeutic approaches targets the pathophysiological pathways leading to aberrant gene activation, namely transcriptional activity and its molecular modulators (agonists, antagonists, coregulators, and nuclear receptors). The transcription factors can be divided into four classes (I-IV) classified by structural elements, like basic leucine zipper (bZIP) or basic helix-loop-helix (bHLH), which mediate their DNA binding activity but also determine the classes of drugs that can affect their activity. For example, statins modulate activation of the class-I transcription factor sterol responsive element-binding protein (SREBP), whose target genes including hydroxyl-methyl-glutaryl acetyl Coenzyme-A (HMG-CoA) reductase, HMG-CoA synthase, and the low-density lipoprotein receptor, all of which are involved in cholesterol and fatty acid metabolism. Similarly, insulin-like drugs target the nuclear receptor peroxisome-proliferator-activator-receptor (PPAR)-gamma (class-II), several anti-inflammatory drugs inhibit activation of nuclear factor kappa B (NFkappaB) (class-IV), while others (e.g. flavopiridol, rapamycin, and paclitaxel) target regulation of cell-cycle proteins. Increased understanding of the genetic and molecular basis of disease (e.g. transcriptional activity and its coregulation) will potentially enhance future diagnosis, treatment, and prevention of vascular diseases.

Arteries↗

PubMedDate not supplied

c-Myc oncoprotein: a dual pathogenic role in neoplasia and cardiovascular diseases?

A growing body of evidence indicates that c-Myc can play a pivotal role both in neoplasia and cardiovascular diseases. Indeed, alterations of the basal machinery of the cell and perturbations of c-Myc-dependent signaling network are involved in the pathogenesis of certain cardiovascular disorders. Down-regulation of c-Myc induced by intervention with antioxidants or by antisense technology may protect the integrity of the arterial wall as well as neoplastic tissues. Further intervention studies are necessary to investigate the effects of tissue-specific block of c-Myc overexpression in the development of cardiovascular diseases.

Animals↗

PubMedDate not supplied

c-Myc oncoprotein: cell cycle-related events and new therapeutic challenges in cancer and cardiovascular diseases.

Advanced stages of both cancer and atherosclerosis are characterized by a local increase in tissue mass that may be hard to control. This increase in tissue mass can be attributed to oxidation-sensitive modification of cell cycle-related events, including cellular proliferation, differentiation, and apoptosis, which could be secondary to alteration in the activity of tumor suppressor gene and oncogene products. The oncogene c-Myc has classically been considered to be involved in carcinogenesis and has more recently been implicated in both endothelial dysfunction and atherogenesis as well. Consequently, inhibition of c-Myc-dependent signaling has become a novel therapeutic opportunity and challenge in atherosclerosis and other cardiovascular diseases. Antioxidant strategies, RNA synthesis inhibitors such as mithramycin, and gene therapeutic approaches with antisense oligonucleotides against c-Myc are some of the promising strategies. In general, the increased biologic understanding of the participation of cell cycle events and targeting these events may enable to attenuate or prevent some of the complications of vascular and neoplastic diseases.

Animals↗