A pilot observational study on magnesium and calcium imbalance in elderly patients with acute aortic dissection.

BACKGROUND: Magnesium (Mg) and calcium (Ca) are the principal essential elements involved in endothelial cell homeostasis. Extracellular changes in the levels of either alter endothelial contraction and dilatation. Consequently Mg and Ca imbalance is associated with a high risk of endothelial dysfunction, the main process observed during acute aortic dissection (AAD); in this clinical condition, which mainly affects elderly men, smooth muscle cell alterations lead to intimal tears, creating a false new lumen in the media of the aorta. AAD patients have a high risk of mortality as a result of late diagnosis because often it is not distinguished from other cardiovascular diseases. We investigated Mg and Ca total circulating levels and the associated pro-inflammatory mediators in elderly AAD patients, to gain further information on the pathophysiology of this disorder, with a view to suggesting newer and earlier potential biomarkers of AAD. RESULTS: Total circulating Mg and Ca levels were both lower in AAD patients than controls (p < 0.0001). Using Ca as cut-off, 90% of AAD patients with low Ca (<8.4 mg/dL) came into the type A classification of AAD. Stratifying AAD according to this cut-off, Mg was lower in patients with lower total Ca. Compared to controls, both type A and B AAD patients had higher levels of all the pro-coagulant and pro-inflammatory mediators analyzed, including sP-sel, D-dimer, TNF-α, IL-6, and CRP (p < 0.05). Dividing types A and B using the Stanford classification, no significant differences were found (p > 0.05) The levels of both ICAM-1 and EN-1 were lower in AAD than in a control group (p < 0.0001 and p < 0.05 respectively). CONCLUSIONS: These findings suggest that low Mg and Ca in AAD elderly patients may contribute to altering normal endothelial physiology and also concur in changing the normal concentrations of different mediators involved in vasodilatation and constriction, associated with AAD onset and severity.

Leucocyte esterase, glucose and C-reactive protein in the diagnosis of prosthetic joint infections: a prospective study.

Analysis of joint fluid is of paramount importance for the diagnosis of prosthetic joint infections. Different markers of inflammation and/or infection in joint fluid have been proposed for diagnosis of these infections. In this study we evaluated the performance of leucocyte esterase, C-reactive protein (CRP) and glucose assays in synovial fluids from 129 patients with septic (n = 27) or aseptic (n = 102) prosthetic joint failure. Samples were collected in serum tubes and centrifuged to limit the presence of corpuscle interfering with the assays. Determinations of leucocyte esterase and glucose were carried out by means of enzymatic colorimetric reactions performed on strips for urine analysis. Tests were considered positive when graded + or ++ whereas traces or absence of colour were considered negative. CRP was measured using an automated turbidimetric method and considered suggestive for infections when >10 mg/L. Leucocyte esterase was positive in 25/27 infected patients and negative in 99/102 not infected patients (sensitivity 92.6%, specificity 97.0%). CRP was higher than the threshold in 22/27 infected patients and in 6/102 not infected patients (sensitivity: 81.5%; specificity: 94.1%) whereas glucose showed the lowest sensitivity (77.8%) and specificity (81.4%), being negative in 21/27 and 19/102 infected and not infected patients, respectively. CRP led to a correct diagnosis in 19 of 22 patients with discordant esterase and glucose results. In conclusion, evaluation of leucocyte esterase, glucose and CRP may represent a useful tool for rapid diagnosis of prosthetic joint infections.

Acute phase of aortic dissection: a pilot study on CD40L, MPO, and MMP-1, -2, 9 and TIMP-1 circulating levels in elderly patients.

BACKGROUND: Acute aortic dissection (AAD) is an event which may be rapidly fatal without early diagnosis and treatment. Aging is one of the main risk factors that could leading to AAD. To date, no specific biomarkers are available to increase the speed of diagnosis. CD40 ligand (CD40L), myeloperoxidase (MPO), matrix metalloproteinase (MMP)-1, -2, -9 and metallopeptidase tissue inhibitor 1 (TIMP-1) are biologically related molecules which integrate inflammation, tissue injury and remodeling, all events associated to AAD. Our is a pilot study to evaluate whether circulating levels of these molecules may be used as potential biomarkers in timely diagnosis of AAD. RESULTS: Within 24 h of symptom onset, circulating CD40L, MPO, MMP-1,-2,-9 and TIMP-1 were quantified by enzyme-linked immunosorbent assays in 22 patients (40-86 years of age) with AAD of ascending aorta (type A according to Stanford classification) and 11 patients with AAD of descending aorta (type B). 30 healthy individuals age matched were used as control group compared to controls, both type A and B AAD patients had higher CD40L (p < 0.001) and MPO (p < 0.01) levels. MMP-1 was higher in the overall AAD group (p < 0.01). After Stanford classification, type A group had increased level compared to both control and type B (p < 0.01 and p < 0.05, respectively). TIMP-1 was higher in both A and B groups compared to controls (p < 0.001). No differences were observed in MMP-2 and MMP-9 levels. CONCLUSIONS: The simultaneous evaluation of CD40L, MPO and MMP-1 and TIMP-1, which may contribute to structural changes in aortic tissue in AAD patients, seems to be a novel promising diagnostic panel.

Epicardial adipocyte hypertrophy: Association with M1-polarization and toll-like receptor pathways in coronary artery disease patients.

BACKGROUND AND AIMS: In coronary artery disease (CAD) epicardial adipose tissue (EAT) shows an elevated inflammatory infiltrate. Toll-like receptors (TLRs) are important mediators of adipose tissue inflammation and they are able to recognize endogenous products released by damaged cells. Because adipocyte death may be driven by hypertrophy, our aim was to investigate in CAD and non-CAD patients the association between EAT adipocyte size, macrophage infiltration/polarization and TLR-2 and TLR-4 expression. METHODS AND RESULTS: EAT biopsies were collected from CAD and non-CAD patients. The adipocyte size was determined by morphometric analysis. Microarray technology was used for gene expression analysis; macrophage phenotype and TLRs expression were analyzed by immunofluorescence and immunohistochemical techniques. Inflammatory mediator levels were determined by immunoassays. EAT adipocytes were larger in CAD than non-CAD patients and do not express perilipin A, a marker of lipid droplet integrity. In CAD, EAT is more infiltrated by CD68-positive cells which are polarized toward an M1 state (CD11c positive) and presents an increased pro-inflammatory profile. Both TLR-2 and TLR-4 expression is higher in EAT from CAD and observed on all the CD68-positive cells. CONCLUSIONS: Our findings suggested that EAT hypertrophy in CAD promotes adipocyte degeneration and drives local inflammation through increased infiltration of macrophages which are mainly polarized towards an M1 state and express both TLR-2 and TLR-4.

Circulating sRAGE in the diagnosis of osteolytic bone metastasis.

Despite the clinical importance of metastasis to the skeleton, the diagnostic tools for early detection and monitoring of bone metastasis lack sensitivity and specificity. We evaluated a promising new serum biomarker, the soluble form of the Receptor of Advanced Glycosylated End-products (sRAGE). sRAGE is involved in the Wnt-signaling pathway, and has been reported to reduce the risk of cancer. We investigated the diagnostic potential of sRAGE to improve the detection and monitoring of bone metastasis. We measured sRAGE in the serum of control healthy subjects, patients with primary tumors and patients with bone metastasis. sRAGE was also correlated with the Wnt inhibitors DKK-1 and sclerostin, the bone resorption markers MMP-2, MMP-9 and TRAP5, and the metastatic marker survivin. sRAGE was significantly lower in primary tumor and metastatic patients than in healthy subjects. sRAGE also showed a strong negative correlation with DKK-1, sclerostin, MMP-2, MMP-9, TRAP5b and survivin. These results indicated that sRAGE might play a protective role in bone metastasis progression, and it may diagnostic significance for detecting and monitoring osteolytic metastases.

Role of hypoxia-inducible factors in the dexrazoxane-mediated protection of cardiomyocytes from doxorubicin-induced toxicity.

BACKGROUND AND PURPOSE: Iron aggravates the cardiotoxicity of doxorubicin, a widely used anticancer anthracycline, and the iron chelator dexrazoxane is the only agent protecting against doxorubicin cardiotoxicity; however, the mechanisms underlying the role of iron in doxorubicin-mediated cardiotoxicity and the protective role of dexrazoxane remain to be established. As iron is required for the degradation of hypoxia-inducible factors (HIF), which control the expression of antiapoptotic and protective genes, we tested the hypothesis that dexrazoxane-dependent HIF activation may mediate the cardioprotective effect of dexrazoxane. EXPERIMENTAL APPROACH: Cell death, protein levels (by immunoblotting) and HIF-mediated transcription (using reporter constructs) were evaluated in the rat H9c2 cardiomyocyte cell line exposed to low doses of doxorubicin with or without dexrazoxane pretreatment. HIF levels were genetically manipulated by transfecting dominant-negative mutants or short hairpin RNA. KEY RESULTS: Treatment with dexrazoxane induced HIF-1α and HIF-2α protein levels and transactivation capacity in H9c2 cells. It also prevented the induction of cell death and apoptosis by exposure of H9c2 cells to clinically relevant concentrations of doxorubicin. Suppression of HIF activity strongly reduced the protective effect of dexrazoxane. Conversely, HIF-1α overexpression protected against doxorubicin-mediated cell death and apoptosis also in cells not exposed to the chelator. Exposure to dexrazoxane increased the expression of the HIF-regulated, antiapoptotic proteins survivin, Mcl1 and haem oxygenase. CONCLUSIONS AND IMPLICATIONS: Our results showing HIF-dependent prevention of doxorubicin toxicity in dexrazoxane-treated H9c2 cardiomyocytes suggest that HIF activation may be a mechanism contributing to the protective effect of dexrazoxane against anthracycline cardiotoxicity.

A phase II trial with cisplatin-paclitaxel cytotoxic treatment and concurrent external and endocavitary radiation therapy in locally advanced or recurrent cervical cancer.

BACKGROUND: Five randomized studies have demonstrated a beneficial effect of adding cisplatin-based chemotherapy to radiation therapy in the treatment of cervical carcinoma. In the present phase II study, we evaluated the response and toxicity of cisplatin-Taxol chemotherapy combined with concomitant radiotherapy in patients with locally advanced cervical carcinoma (LACC) and locally recurrent cervical carcinoma (LRCC). PATIENTS AND METHODS: In 2000, this phase II study was initiated with a chemotherapy regimen of cisplatin (75 mg/m(2)) and Taxol (175 mg/m(2)) every 21 days, for four cycles, concomitant with external radiotherapy and high-dose-rate brachytherapy. Pelvic radiotherapy was started 2 weeks after the first chemotherapy cycle, while the first brachytherapy insertion was carried out during the fourth chemotherapy cycle. SCC marker was determined before treatment and after every chemotherapy cycle. RESULTS: All of the 27 patients treated achieved a complete clinical response. Two patients with LACC experienced distant recurrence 22 and 24 months after complete response, respectively, and 1 patient with LRCC had local progression 6 months after the end of radiotherapy. Although generally tolerable, neutropenia grade 3-4 in 4 patients and anemia grade 3 in 2 patients were observed, and 1 patient experienced grade 2 neurotoxicity; toxicity due to radiotherapy was moderate. CONCLUSIONS: Concomitant cisplatin-Taxol chemoradiotherapy seems to be well tolerated, and results, even in this small series, are encouraging.

Hepatocyte growth factor-activated NF-kappaB regulates HIF-1 activity and ODC expression, implicated in survival, differently in different carcinoma cell lines.

Hepatocyte growth factor (HGF)-stimulated Met signaling influences tumor survival, growth and progression, all processes involving the transcription factor NF-kappaB. NF-kappaB plays a complex role in the control of survival due to the influence of cellular factors acting downstream. We undertook a comparative investigation of two human breast carcinoma cells with different grades of malignancy and HepG2 hepatoma cells, which present a biphasic response to HGF (proliferation followed by apoptosis). We found evidence that HGF induced gene patterns characteristic of survival rather than apoptosis depending on the cell type. The ability of NF-kappaB to regulate expression of hypoxia-inducible factor-1alpha (HIF-1alpha), a survival/anti-apoptotic gene in cancer, seemed to be critical. In the HepG2 and MCF-7 (low invasive breast carcinoma) cell lines increased transcription and translation were responsible for HIF-1alpha induction after HGF. The regulation by NF-kappaB was mainly at the level of the 5'-UTR of the HIF-1alpha message. HIF-1 (alpha/beta heterodimer) was likely to transactivate Mcl-1, another anti-apoptotic gene. Opposite results were observed in MDA-MB-231 cells (highly invasive breast carcinoma), which have high NF-kappaB activity, further inducible by HGF, because HIF-1alpha mRNA expression and HIF-1 transactivating capacity were HGF-insensitive while the alpha subunit seemed to be degraded after HGF. However, ornithine decarboxylase (ODC) and heme oxygenase mRNA expression persistently increased. By transiently transfecting two ODC gene reporters we demonstrated that ODC is a target gene of NF-kappaB in HGF-treated tumor cells. By regulating HIF-1 activity and specific gene expression downstream, NF-kappaB may influence the survival threshold, with an impact on the fate of carcinoma cells after prolonged HGF treatment.

Hepatocyte growth factor signalling stimulates hypoxia inducible factor-1 (HIF-1) activity in HepG2 hepatoma cells.

Hepatocyte growth factor (HGF), a multifunctional cytokine of mesenchymal origin, activates the DNA binding of hypoxia inducible factor-1 (HIF-1) in the HepG2 cell line: the activated complex contained the inducible alpha subunit. An increased expression of HIF-1alpha (mRNA and nuclear protein levels) was observed. To investigate the molecular basis of the HIF-1 response under this non-hypoxic condition, we evaluated first the expression of putative target genes. We found a time-dependent increase in steady-state mRNA levels of heme oxygenase and urokinase plasminogen activator at 4 h, followed by that of urokinase receptor at 10 h. The enhanced expression of these genes might confer the invasive phenotype, since HGF is a proliferative and scatter factor. Second, we examined some aspects of HIF-1 activity regulation in HGF-treated cells with the following findings: (i) the activation of HIF-1 DNA binding was prevented by proteasome blockade, probably because stabilization of the cytosolic alpha-subunit protein level is not sufficient to generate a functional form: also under these conditions nuclear protein level of HIF-1alpha did not increase; (ii) N-acetylcysteine, a free radical scavenger, strongly decreased HIF-1 activation suggesting a role of reactive oxygen species in this process; (iii) the thiol reducing agent dithiothreitol was ineffective. Third, consistent with these data, N-acetylcysteine reduced the stimulatory effect of HGF on stress kinase activities, while p42/44 mitogen activated kinase (MAPK) was unmodified, suggesting an involvement of c-Jun-N-terminal kinase (JNK) and p38 MAPK in HIF-1 activation. Finally, LY 294002 induced the blockade of phosphatidylinositol 3-kinase (PI3K), one of the principal transducers of HGF/Met receptor signalling, prevented the enhancement of HIF-1 DNA binding and JNK activity, but the inhibition of p42/44 MAPK phosphorylation with PD 98059 was ineffective. In conclusion, we suggest that HGF triggers a signal transduction cascade involving PI3K and ultimately activates HIF-1.

Influence of proteasome and redox state on heat shock-induced activation of stress kinases, AP-1 and HSF.

We studied the pattern of activation of stress kinases and of transcription factors activator protein-1 (AP-1) and heat shock factor (HSF) in FAO cells by combining two treatments, i.e. heating (42 degrees C for 1 h) and proteasome inhibition, each known to cause cellular heat shock response. The co-treatment heat shock (HS) and proteasome inhibitor (a peptidyl aldehyde or lactacystin) showed cumulative effects on the intensity and duration of activation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) at the end of the HS period and during recovery. Similarly, the thiol-reducing agents N-(2-mercaptoethyl)-1,3-diaminopropane and dithiothreitol strongly activated both JNK and p38 MAPK in cells undergoing HS. AP-1 DNA binding activity in response to proteasome inhibitors was so strong that it shadowed the stimulatory effect of HS in the combined treatment, but lactacystin, which is the most potent and specific proteasome inhibitor, decreased the binding late during recovery from HS. Thiol-reducing agents prevented AP-1 DNA binding induced by HS. The combined HS/proteasome inhibitors or HS/thiol-reducing agents treatments cooperatively activated HSF DNA binding. Expression of collagenase I and hsp 70 mRNAs reflects the different behavior of AP-1 and HSF transcription factors in cells exposed to HS and proteasome inhibition. The data seem to indicate that JNK and p38 MAPK activations are not necessarily coupled to DNA binding of AP-1, which can be either increased or inhibited when these kinases are activated. AP-1 and HSF show opposite patterns of response to HS in the presence of proteasome inhibitors or reducing agents.

Hepatocyte growth factor signal coupling to various transcription factors depends on triggering of Met receptor and protein kinase transducers in human hepatoma cells HepG2.

Hepatocyte growth factor (HGF) regulates a wide variety of biological activities by binding to the tyrosine kinase receptor Met. In HGF-treated hepatocarcinoma cells, we observed a biphasic activation of AP-1 and AP-2 transcription factors. For NF-kappaB complex the p50-p50 homodimer was activated before the p50-p65 heterodimer, and c-Myc/Max DNA-binding activity increased thereafter. Since these transcription factors are responders to mitogenic stimulation through protein kinase transducers, we tested the effects of inhibitors of these enzymes on the DNA binding after HGF treatment. Inhibition of protein kinase C (PKC) with H7 strikingly activated NF-kappaB above the values observed after HGF alone. Under this inhibitory condition, Met tyrosine phosphorylation was elevated as though the phosphorylation-dependent activity of the receptor was partially blocked by activation of PKC due to HGF. NF-kappaB DNA binding seems to be related to Met triggering by HGF since it was largely prevented by genistein treatment, which blocks receptor activity. Phosphatidylinositol 3-kinase seems to be involved in AP-1 binding activity stimulated by HGF. It is noteworthy that Met is responsive to HGF stimulating postreceptor signaling, which converges on the activation of transcription factors acting coordinately to regulate target gene expression.

HIF-1-mediated activation of transferrin receptor gene transcription by iron chelation.

Treatment with iron chelators mimics hypoxic induction of the hypoxia inducible factor (HIF-1) which activates transcription by binding to hypoxia responsive elements (HRE). We investigated whether HIF-1 is involved in transcriptional activation of the transferrin receptor (TfR), a membrane protein which mediates cellular iron uptake, in response to iron deprivation. The transcription rate of the TfR gene in isolated nuclei was up-regulated by treatment of Hep3B human hepatoma cells with the iron chelator desferrioxamine (DFO). The role of HIF-1 in the activation of TfR was indicated by the following observations: (i) DFO-dependent activation of a luciferase reporter gene in transfected Hep3B cells was mediated by a fragment of the human TfR promoter containing a putative HRE sequence; (ii) mutation of this sequence prevented stimulation of luciferase activity; (iii) binding to this sequence of HIF-1alpha, identified by competition experiments and supershift assays, was induced by DFO. Furthermore, in mouse hepatoma cells unable to assemble functional HIF-1, inducibility of TfR transcription by DFO was lost and TfR mRNA up-regulation was reduced. These results, which show the role of HIF-1 in the control of TfR gene expression in conditions of iron depletion, give insights into the mechanisms of transcriptional regulation which concur with the well-characterized post-transcriptional control of TfR expression to expand the extent of response to iron deficiency.

Transferrin receptor induction by hypoxia. HIF-1-mediated transcriptional activation and cell-specific post-transcriptional regulation.

The tight relationship between oxygen and iron prompted us to investigate whether the expression of transferrin receptor (TfR), which mediates cellular iron uptake, is regulated by hypoxia. In Hep3B human hepatoma cells incubated in 1% O(2) or treated with CoCl(2), which mimics hypoxia, we detected a 3-fold increase of TfR mRNA despite a decrease of iron regulatory proteins activity. Increased expression resulted from a 4-fold stimulation of the nuclear transcription rate of the TfR gene by both hypoxia and CoCl(2). A role for hypoxia-inducible factor (HIF-1), which activates transcription by binding to hypoxia-responsive elements in the activation of TfR, stems from the following observations. (a) Hypoxia and CoCl(2)-dependent expression of luciferase reporter gene in transiently transfected Hep3B cells was mediated by a fragment of the human TfR promoter containing a putative hypoxia-responsive element sequence, (b) mutation of this sequence prevented hypoxic stimulation of luciferase activity, (c) binding to this sequence of HIF-1alpha, identified by competition experiments and supershift assays, was induced in Hep3B cells by hypoxia and CoCl(2). In erythroid K562 cells, the same treatments did not affect iron regulatory proteins activity, thus resulting in a stimulation of TfR gene expression higher than in hepatoma cells.

Influence of polyamines on DNA binding of heat shock and activator protein 1 transcription factors induced by heat shock.

Polyamine depletion, obtained in FAO cells with specific inhibitors of biosynthetic enzymes, prevents or decreases the accumulation of hsp 70 mRNA following heat shock [Desiderio et al., Hepatology 24 (1996) 150-156]. The present study shows that under conditions of spermidine depletion caused by alpha-difluoromethylornithine, the DNA binding capacity of the transcription factor HSF induced by heat shock undergoes a severe and prompt deactivation. Replenishment of the spermidine pool before heat shock re-establishes the DNA binding activity of HSF and the inducibility of hsp 70 mRNA. Similar to HSF, but with a different time-course, the DNA binding of the transcription factor AP-1 activated by heat shock is also impaired in spermidine-depleted cells and reversed by exogenous spermidine. STAT3 provides an example of a transcription factor slightly activated by heat shock but insensitive to polyamine decrease.

Differential activation of some transcription factors during rat liver ischemia, reperfusion, and heat shock.

Cells respond to external stimuli by changes in gene expression that are largely dependent on transcription factors (TFs). We studied the behavior of some TFs in rat liver during ischemia, postischemic reperfusion, and heat shock. Knowledge of the conditions at the end of ischemia is essential to understand changes occurring at reperfusion. The TFs investigated are known to be typically responsive to heat shock (HSF), hypoxia (HIF-1), pro- and antioxidant conditions (AP-1), or to various environmental changes (HNF-1 and ATF/CREB family). The most relevant new information includes the following: 1) Liver ischemia activates extremely rapidly the DNA binding capacity of HSF, soon followed by analogous activation of HIF-1 and AP-1. 2) After a certain lag time from the activation of HIF-1, mRNAs accumulate for two glycolytic enzymes, in particular Aldolase A and Heme Oxygenase 1, which contain HIF-1 sequences in their promoters. 3) Reperfusion, which is known to further increase the binding of HSF and to induce NFkappaB binding, abrogates or decreases the binding of HIF-1 and AP-1, stimulated by ischemia, and activates the binding of ATF/CREB. Later on, a second peak of AP-1 binding is induced. 4) Heat shock activates both ischemia-responsive and reperfusion-responsive TFs. 5) Preliminary experiments of supergelshift reveal that the activation of AP-1 at reperfusion or upon heat shock may result from the different involvement of the component subunits.

Effect of reactive oxygen species on iron regulatory protein activity.

Iron may be important in catalyzing excessive production of reactive oxygen species (ROS). Cellular iron homeostasis is regulated by iron regulatory proteins (IRPs), which bind to iron-responsive elements (IRE) of mRNAs for ferritin and transferrin receptor (TfR) modulating iron uptake and sequestration, respectively. Although iron is the main regulator of IRP activity, IRP is also influenced by other factors, including the redox state. Therefore, IRP might be sensitive to pathophysiological alterations of redox state caused by ROS. However, previous studies have produced diverging evidence on the effect of oxidative injury on IRP. Results obtained in an animal model close to a pathophysiological condition, such as ischemia reperfusion of the liver as well as in a cell-free system involving an enzymatic source of O2 and H2O2, indicate that IRP is downregulated by oxidative stress. In fact, IRP activity is inhibited at early times of post-ischemic reperfusion. Moreover, the concerted action of O2 and H2O2 produced by xanthine oxidase in a cell-free system caused a remarkable inhibition of IRP activity. IRP seems a direct target of ROS; in fact, in vivo inhibition can be prevented by the antioxidant N-acetylcysteine and by interleukin-1 receptor antagonist. In addition, modulation of iron levels of the cell-free assay did not affect the downregulation imposed by xanthine oxidase. Conceivably, downregulation of IRP activity by O2 and H2O2 may facilitate iron sequestration into ferritin, thus limiting the pro-oxidant challenge of iron.