Exosomal-miRNas expression and growth factors released by mononuclear cells of CLAD patients in response to extracorporeal photopheresis

BACKGROUND

CLAD (Chronic Lung Allograft Dysfunction) remains a serious complication following lung transplantation. Some evidence shows that portions of Extracorporeal Photopheresis (ECP)-treated patients improve/stabilize their graft function. In spite of that, data concerning molecular mechanisms are still lacking. Aims of our study were to assess whether ECP effects are mediated by Mononuclear Cells (MNCs) modulation in term of microRNAs (miRNAs) expression and growth factors release.

METHODS

Cells from leukapheresis of 16 CLAD patients, at time 0 and 6-months (10 cycles), were cultured for 48h ± PHA (10 ug/ml) or LPS (2 ug/ml). Expression levels of miR-146a-5p, miR-155-5p, miR-31-5p, miR181a-5p, miR-142-3p, miR-16-5p and miR-23b-5p in MNCs-exosomes were evaluated by qRT-PCR, while ELISA assessed different growth factors levels on culture supernatants.

RESULTS

Our result showed miR-142-3p down-regulation (p = 0.02) in MNCs of ECP-patients after the 10 cycles and after LPS stimulation (p = 0.005). We also find miR-146a-5p up-regulation in cells after the 10 cycles stimulated with LPS (p = 0.03). Connective tissue growth factor (CTGF) levels significantly decreased in MNCs supernatant (p = 0.04). The effect of ECP is translated into frequency changes of Dendritic Cell (DC) subpopulations and a slight increase in T regulatory cells (Treg) number and a significant decrease in CTGF release.

CONCLUSIONS

ECP might affect regulatory T cell functions, since both miR-142 and miR-146a have been shown to be involved in the regulation of suppressor regulatory T cell functions and DCs. On the other side ECP, possibly by regulating macrophage activation, is able to significantly down modulate CTGF release.

Agreement between local and central anti-synthetase antibodies detection: results from the Classification Criteria of Anti-Synthetase Syndrome project biobank

OBJECTIVES

The CLASS (Classification Criteria of Anti-Synthetase Syndrome) project is a large international multicentre study that aims to create the first data-driven anti-synthetase syndrome (ASSD) classification criteria. Identifying anti-aminoacyl tRNA synthetase antibodies (anti-ARS) is crucial for diagnosis, and several commercial immunoassays are now available for this purpose. However, using these assays risks yielding false-positive or false-negative results, potentially leading to misdiagnosis. The established reference standard for detecting anti-ARS is immunoprecipitation (IP), typically employed in research rather than routine autoantibody testing. We gathered samples from participating centers and results from local anti-ARS testing. As an "ad-interim" study within the CLASS project, we aimed to assess how local immunoassays perform in real-world settings compared to our central definition of anti-ARS positivity.

METHODS

We collected 787 serum samples from participating centres for the CLASS project and their local anti-ARS test results. These samples underwent initial central testing using RNA-IP. Following this, the specificity of ARS was reconfirmed centrally through ELISA, line-blot assay (LIA), and, in cases of conflicting results, protein-IP. The sensitivity, specificity, positive likelihood ratio and positive and negative predictive values were evaluated. We also calculated the inter-rater agreement between central and local results using a weighted κ co-efficient.

RESULTS

Our analysis demonstrates that local, real-world detection of anti-Jo1 is reliable with high sensitivity and specificity with a very good level of agreement with our central definition of anti-Jo1 antibody positivity. However, the agreement between local immunoassay and central determination of anti-non-Jo1 antibodies varied, especially among results obtained using local LIA, ELISA and "other" methods.

CONCLUSIONS

Our study evaluates the performance of real-world identification of anti-synthetase antibodies in a large cohort of multi-national patients with ASSD and controls. Our analysis reinforces the reliability of real-world anti-Jo1 detection methods. In contrast, challenges persist for anti-non-Jo1 identification, particularly anti-PL7 and rarer antibodies such as anti-OJ/KS. Clinicians should exercise caution when interpreting anti-synthetase antibodies, especially when commercial immunoassays test positive for non-anti-Jo1 antibodies.

Investigating the Link between Alpha-1 Antitrypsin and Human Neutrophil Elastase in Bronchoalveolar Lavage Fluid of COVID-19 Patients

Neutrophils play a pathogenic role in COVID-19 by releasing Neutrophils Extracellular Traps (NETs) or human neutrophil elastase (HNE). Given that HNE is inhibited by α1-antitrypsin (AAT), we aimed to assess the content of HNE, α1-antitrypsin (AAT) and HNE-AAT complexes (the AAT/HNE balance) in 33 bronchoalveolar lavage fluid (BALf) samples from COVID-19 patients. These samples were submitted for Gel-Electrophoresis, Western Blot and ELISA, and proteins (bound to AAT or HNE) were identified by Liquid Chromatography-Mass Spectrometry. NETs' release was analyzed by confocal microscopy. Both HNE and AAT were clearly detectable in BALf at high levels. Contrary to what was previously observed in other settings, the formation of HNE-AAT complex was not detected in COVID-19. Rather, HNE was found to be bound to acute phase proteins, histones and C3. Due to the relevant role of NETs, we assessed the ability of free AAT to bind to histones. While confirming this binding, AAT was not able to inhibit NET formation. In conclusion, despite the finding of a high burden of free and bound HNE, the lack of the HNE-AAT inhibitory complex in COVID-19 BALf demonstrates that AAT is not able to block HNE activity. Furthermore, while binding to histones, AAT does not prevent NET formation nor their noxious activity.

Differential expression of circulating miRNAs after alemtuzumab induction therapy in lung transplantation

Alemtuzumab is a monoclonal antibody targeting CD52, used as induction therapy after lung transplantation (LTx). Its engagement produces a long-lasting immunodepletion; however, the mechanisms driving cell reconstitution are poorly defined. We hypothesized that miRNAs are involved in this process. The expression of a set of miRNAs, cytokines and co-signaling molecules was measured with RT-qPCR and flow cytometry in prospectively collected serum samples of LTx recipients, after alemtuzumab or no induction therapy. Twenty-six LTx recipients who received alemtuzumab and twenty-seven matched LTx recipients without induction therapy were included in the analysis. One year after transplantation four miRNAs were differentially regulated: miR-23b (p = 0.05) miR-146 (p = 0.04), miR-155 (p < 0.001) and miR-486 (p < 0.001). Expression of 3 miRNAs changed within the alemtuzumab group: miR-146 (p < 0.001), miR-155 (p < 0.001) and miR-31 (p < 0.001). Levels of IL-13, IL-4, IFN-γ, BAFF, IL-5, IL-9, IL-17F, IL-17A and IL-22 were different one year after transplantation compared to baseline. In no-induction group, concentration of sCD27, sB7.2 and sPD-L1 increased overtime. Expression of miR-23b, miR-146, miR-486, miR-155 and miR-31 was different in LTx recipients who received alemtuzumab compared to recipients without induction therapy. The observed cytokine pattern suggested proliferation of specific B cell subsets in alemtuzumab group and co-stimulation of T-cells in no-induction group.

Mechanisms of Action of Extracorporeal Photopheresis in the Control of Bronchiolitis Obliterans Syndrome (BOS): Involvement of Circulating miRNAs

Clinical evidence suggests an improvement or stabilization of lung function in a fraction of patients with bronchiolitis obliterans syndrome (BOS) treated by extracorporeal photopheresis (ECP); however, few studies have explored the epigenetic and molecular regulation of this therapy. The aim of present study was to evaluate whether a specific set of miRNAs were significantly regulated by ECP. Total RNA was isolated from serum of patients with established BOS grade 1–2 prior to the start and after 6 months of ECP treatment. We observed a significant downregulation of circulating hsa-miR-155-5p, hsa-miR-146a-5p and hsa-miR-31-5p in BOS patients at the start of ECP when compared to healthy subjects. In responders, increased miR-155-5p and decreased miR-23b-3p expression levels at 6 months were found. SMAD4 mRNA was found to be a common target of these two miRNAs in prediction pathways analysis, and a significant downregulation was found at 6 months in PBMCs of a subgroup of ECP-treated patients. According to previous evidence, the upregulation of miR-155 might be correlated with a pro-tolerogenic modulation of the immune system. Our analysis also suggests that SMAD4 might be a possible target for miR-155-5p. Further longitudinal studies are needed to address the possible role of miR-155 and its downstream targets.

The interferon landscape along the respiratory tract impacts the severity of COVID-19

Severe coronavirus disease 2019 (COVID-19) is characterized by overproduction of immune mediators, but the role of interferons (IFNs) of the type I (IFN-I) or type III (IFN-III) families remains debated. We scrutinized the production of IFNs along the respiratory tract of COVID-19 patients and found that high levels of IFN-III, and to a lesser extent IFN-I, characterize the upper airways of patients with high viral burden but reduced disease risk or severity. Production of specific IFN-III, but not IFN-I, members denotes patients with a mild pathology and efficiently drives the transcription of genes that protect against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In contrast, compared to subjects with other infectious or noninfectious lung pathologies, IFNs are overrepresented in the lower airways of patients with severe COVID-19 that exhibit gene pathways associated with increased apoptosis and decreased proliferation. Our data demonstrate a dynamic production of IFNs in SARS-CoV-2-infected patients and show IFNs play opposing roles at distinct anatomical sites.

Neutrophil Extracellular Traps Induce the Epithelial-Mesenchymal Transition: Implications in Post-COVID-19 Fibrosis

The release of neutrophil extracellular traps (NETs), a process termed NETosis, avoids pathogen spread but may cause tissue injury. NETs have been found in severe COVID-19 patients, but their role in disease development is still unknown. The aim of this study is to assess the capacity of NETs to drive epithelial-mesenchymal transition (EMT) of lung epithelial cells and to analyze the involvement of NETs in COVID-19. Bronchoalveolar lavage fluid of severe COVID-19 patients showed high concentration of NETs that correlates with neutrophils count; moreover, the analysis of lung tissues of COVID-19 deceased patients showed a subset of alveolar reactive pneumocytes with a co-expression of epithelial marker and a mesenchymal marker, confirming the induction of EMT mechanism after severe SARS-CoV2 infection. By airway in vitro models, cultivating A549 or 16HBE at air-liquid interface, adding alveolar macrophages (AM), neutrophils and SARS-CoV2, we demonstrated that to trigger a complete EMT expression pattern are necessary the induction of NETosis by SARS-CoV2 and the secretion of AM factors (TGF-β, IL8 and IL1β). All our results highlight the possible mechanism that can induce lung fibrosis after SARS-CoV2 infection.

POS0426 CIRCULATING MICRORNA PROFILING IN PATIENTS WITH ANTI-SYNTHETASE SYNDROME AND INTERSTITIAL LUNG DISEASE

Background:

Anti-synthetase syndrome (ASSD) is an autoimmune disease characterized by autoantibodies against one of many aminoacyl transfer RNA (tRNA) synthetases. Interstitial Lung Disease (ILD) in ASSD patients is frequent, often severe and rapidly progressive, causing much of the increased morbidity and mortality associated with ASSD as compared to other idiopathic inflammatory myopathies [1].

Objectives:

In this study, we hypothesized that immune-related miRNAs may be associated with presence/absence of lung involvement in patients with ASSD and help predict disease course.

Methods:

A total of 15 ASSD patients were enrolled: 11 with ILD and 4 without ILD. Differentially expressed miRNAs were identified in plasma derived-exosome, using miRNA PCR array (MIHS-111ZG, Qiagen) including 84 miRNAs involved in activation and differentiation of T and B cells.

Results:

Among all miRNAs analyzed we found that miR-15b-5p, miR-23a-3p, miR-25-3p, miR-30a-5p and miR29c-3p were up-regulated in ASSD-ILD patients (p<0.05) as compared to patients without lung involvement (Figure 1). To evaluate the effectiveness of the five miRNAs for predicting ILD among ASSD patients, ROC curves were constructed. The AUCs of miR-15b-5p, miR-25-3p, miR-30a-5p and miR29c-3p were 0.83, 0.87, 0.86 and 0.89, respectively (p= 0.05 for miR-25-3p and p<0.05 for all other curves). The prediction of the biologic targets and pathways as well as cellular processes by DIANA-mirPath analysis showed that all miRNAs associated with ILD presence are involved in PI3K-Akt signaling pathway.

Conclusion:

Our study shows that, in ASSD patients with ILD, miR-15b-5p, miR-23a-3p, miR-25-3p, miR-30a-5p and miR29c-3p were up-regulated compared to patients without evidence of ILD. A clear involvement in immune and inflammatory diseases was documented for the miRNAs identified [2] and, for many of these, studies in the literature indicate a possible role in pulmonary fibrosis [3]. It is notable that these miRNAs were related to PI3K-Akt signaling pathway that regulate cell proliferation, differentiation and apoptosis [4]. It has also been demonstrated that in lung fibroblast the PI3K–Akt signals can be aberrantly activated [5]. The identification of markers could be important in the early identification of the disease and for its treatment.

References:

[1]Kalluri M, Oddis CV. Pulmonary manifestations of the idiopathic inflammatory myopathies. Clinics in chest medicine. 2010; 31:501–512.

[2]Prabahar A, Natarajan J, ImmunemiR-a database of prioritized immune miRNA disease associations and its interactome. MicroRNA, 2017; 6: 71–78.

[3]Sessa R, Hata A. Role of microRNAs in lung development and pulmonary diseases. Pulm Circ. 2013; 3:315-28.

[4]Ersahin T, Tuncbag N, Cetin-Atalay R. The PI3K/AKT/mTOR interactive pathway. Mol Biosyst. 2015;11:1946-54.

[5]Zhang XL, Xing RG, Chen L, Liu CR, Miao ZG. PI3K/Akt signaling is involved in the pathogenesis of bleomycin-induced pulmonary fibrosis via regulation of epithelial-mesenchymal transition. Mol Med Rep. 2016;14:5699-5706.

Figure 1.

Comparison of relative levels of five miRNAs among patients with and without lung involvement were expressed as log2 transformed values. *p<0.05; **p<0.01

Disclosure of Interests:

None declared

Loading Imatinib inside targeted nanoparticles to prevent Bronchiolitis Obliterans Syndrome

Bronchiolitis Obliterans Syndrome seriously reduces long-term survival of lung transplanted patients. Up to now there is no effective therapy once BOS is established. Nanomedicine introduces the possibility to administer drugs locally into lungs increasing drug accumulation in alveola reducing side effects. Imatinib was loaded in gold nanoparticles (GNP) functionalized with antibody against CD44 (GNP-HCIm). Lung fibroblasts (LFs) were derived from bronchoalveolar lavage of BOS patients. GNP-HCIm cytotoxicity was evaluated by MTT assay, apoptosis/necrosis and phosphorylated-cAbl (cAbl-p). Heterotopic tracheal transplantation (HTT) mouse model was used to evaluate the effect of local GNP-HCIm administration by Alzet pump. GNP-HCIm decreased LFs viability compared to Imatinib (44.4 ± 1.8% vs. 91.8 ± 3.2%, p < 0.001), inducing higher apoptosis (22.68 ± 4.3% vs. 6.43 ± 0.29; p < 0.001) and necrosis (18.65 ± 5.19%; p < 0.01). GNP-HCIm reduced cAbl-p (0.41 GNP-HCIm, 0.24 Imatinib vs. to control; p < 0.001). GNP-HCIm in HTT mouse model by Alzet pump significantly reduced tracheal lumen obliteration (p < 0.05), decreasing apoptosis (p < 0.05) and TGF-β-positive signal (p < 0.05) in surrounding tissue. GNP-HCIm treatment significantly reduced lymphocytic and neutrophil infiltration and mast cells degranulation (p < 0.05). Encapsulation of Imatinib into targeted nanoparticles could be considered a new option to inhibit the onset of allograft rejection acting on BOS specific features.

Broncho-alveolar inflammation in COVID-19 patients: a correlation with clinical outcome

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly reached pandemic proportions. Given that the main target of SARS-CoV-2 are lungs leading to severe pneumonia with hyperactivation of the inflammatory cascade, we conducted a prospective study to assess alveolar inflammatory status in patients with moderate to severe COVID-19.

METHODS

Diagnostic bronchoalveolar lavage (BAL) was performed in 33 adult patients with SARS-CoV-2 infection by real-time PCR on nasopharyngeal swab admitted to the Intensive care unit (ICU) (n = 28) and to the Intermediate Medicine Ward (IMW) (n = 5). We analyze the differential cell count, ultrastructure of cells and Interleukin (IL)6, 8 and 10 levels.

RESULTS

ICU patients showed a marked increase in neutrophils (1.24 × 10⁵ ml^- 1, 0.85-2.07), lower lymphocyte (0.97 × 10⁵ ml^- 1, 0.024-0.34) and macrophages fractions (0.43 × 10⁵ ml^- 1, 0.34-1.62) compared to IMW patients (0.095 × 10⁵ ml^- 1, 0.05-0.73; 0.47 × 10⁵ ml^- 1, 0.28-1.01 and 2.14 × 10⁵ ml^- 1, 1.17-3.01, respectively) (p < 0.01). Study of ICU patients BAL by electron transmission microscopy showed viral particles inside mononuclear cells confirmed by immunostaining with anti-viral capsid and spike antibodies. IL6 and IL8 were significantly higher in ICU patients than in IMW (IL6 p < 0.01, IL8 p < 0.0001), and also in patients who did not survive (IL6 p < 0.05, IL8 p = 0.05 vs. survivors). IL10 did not show a significant variation between groups. Dividing patients by treatment received, lower BAL concentrations of IL6 were found in patients treated with steroids as compared to those treated with tocilizumab (p < 0.1) or antivirals (p < 0.05).

CONCLUSIONS

Alveolitis, associated with COVID-19, is mainly sustained by innate effectors which showed features of extensive activation. The burden of pro-inflammatory cytokines IL6 and IL8 in the broncho-alveolar environment is associated with clinical outcome.

Hyaluronic Acid-Decorated Liposomes as Innovative Targeted Delivery System for Lung Fibrotic Cells

Collagen Tissue Disease-associated Interstitial Lung Fibrosis (CTD-ILDs) and Bronchiolitis Obliterans Syndrome (BOS) represent severe lung fibrogenic disorders, characterized by fibro-proliferation with uncontrolled extracellular matrix deposition. Hyaluronic acid (HA) plays a key role in fibrosis with its specific receptor, CD44, overexpressed by CTD-ILD and BOS cells. The aim is to use HA-liposomes to develop an inhalatory treatment for these diseases. Liposomes with HA of two molecular weights were prepared and characterized. Targeting efficiency was assessed toward CTD-ILD and BOS cells by flow cytometry and confocal microscopy and immune modulation by RT-PCR and ELISA techniques. HA-liposomes were internalized by CTD-ILD and BOS cells expressing CD44, and this effect increased with higher HA MW. In THP-1 cells, HA-liposomes decreased pro-inflammatory cytokines IL-1β, IL-12, and anti-fibrotic VEGF transcripts but increased TGF-β mRNA. However, upon analyzing TGF-β release from healthy donors-derived monocytes, we found liposomes did not alter the release of active pro-fibrotic cytokine. All liposomes induced mild activation of neutrophils regardless of the presence of HA. HA liposomes could be also applied for lung fibrotic diseases, being endowed with low pro-inflammatory activity, and results confirmed that higher MW HA are associated to an increased targeting efficiency for CD44 expressing LFs-derived from BOS and CTD-ILD patients.

sRAGE and early signs of cardiac target organ damage in mild hypertensives

Background

Soluble Receptor for Advanced Glycation End Products (sRAGE) may be considered a marker inversely related to inflammation and its participation has been established in patients with advanced atherosclerotic vascular diseases. However, it is still unknown whether sRAGE reduction could be early metabolic change in the first stage of hypertension and initial hypertension-associated cardiac damage. We sought to determine the sRAGE values in otherwise healthy, untreated and recently diagnosed mild hypertensives and evaluate their association with blood pressure (BP) values, metabolic parameters, and with subclinical initial signs of cardiac target organ damage (TOD).

Methods

sRAGE were measured in 100 hypertensive and 100 normotensive subjects matched for age, gender and body mass index (BMI), submitted to a clinic visit and both ambulatory BP monitoring and echocardiography to determine the presence of initial cardiac TOD (presence of signs of left ventricular hypertrophy: left ventricular mass indexed for height^2.7 (LVMi) > 48 g/m^2.7 for men and > 44 g/m^2.7 for women and/or increased left atrial volume 4-chamber indexed for body surface area (LAVi) > 34 ml/m²).

Results

sRAGE levels were similar between hypertensive and normotensive subjects and were not significantly correlated with office and 24-h BPs values. However, when subgrouping the hypertensive patients in Hyp-TOD and Hyp-withoutTOD, sRAGE was found to be different among the three groups (p = 0.030), being lower in the Hyp-TOD group than the values of both Hyp-withoutTOD (p = 0.038) and normotensives (p = 0.038). In hypertensive patients sRAGE was negatively related with both LVMi (r = − 0.239, p = 0.034) and LAVi (r = − 0.315, p = 0.005) and was independently related to cardiac TOD also in multivariable analysis.

Conclusions

In this population of mild hypertensives, low circulating sRAGE may be a very early marker of initial TOD, suggesting the possible participation of oxidative stress in initial cardiac changes in human hypertension.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0821-5) contains supplementary material, which is available to authorized users.

Cardiovascular characteristics of chronic fatigue syndrome

Patients with chronic fatigue syndrome (CFS) commonly exhibit orthostatic intolerance. Abnormal sympathetic predominance in the autonomic cardiovascular response to gravitational stimuli was previously described in numerous studies. The aim of the current study was to describe cardiological and clinical characteristics of Italian patients with CFS. All of the patients were of Caucasian ethnicity and had been referred to our center, the Cardiology Department of the University Hospital of Pavia (Pavia, Italy) with suspected CFS. A total of 44 patients with suspected CFS were included in the present study and the diagnosis was confirmed in 19 patients according to recent clinical guidelines. The characteristics at baseline of the population confirm findings from various previous reports regarding the prevalence in females with a female to male ratio of 4:1, the age of onset of the pathology and the presence of previous infection by the Epstein-Barr virus, cytomegalovirus and other human herpesviruses. Despite the current data indicating that the majority of the cardiological parameters investigated are not significantly different in patients with and without CFS, a significant association between the disease and low levels of blood pressure was identified. Other pilot studies revealed a higher prevalence of hypotension and orthostatic intolerance in patients with CFS. Furthermore, many of the CFS symptoms, including fatigue, vertigo, decreased concentration, tremors and nausea, may be explained by hypotension.

Time-domain heart rate variability in coronary artery disease patients affected by thyroid dysfunction

Subclinical hypothyroidism and hyperthyroidism have been recognized as clinical entities with negative effects on the cardiovascular system. Moreover, the effect of treated thyroid dysfunction on parameters associated with the cardiovascular control system has been poorly investigated. In the present study we analyzed time-domain heart rate variability in coronary artery disease (CAD) patients with known thyroid diseases. Twenty-four hour ECG monitoring was performed in 344 patients with coronary artery disease (174 with thyroid dysfunction and 170 without thyroid dysfunction used as a control group), using a 3-channel tape recorder. Time domain parameters of heart rate variability (HRV) were definitely lower both in patients with subclinical hypothyroidism and subclinical hyperthyroidism than in the control group, with statistically significant differences in SDNN, RMSSD, TINN, and mean RR for both subgroups. Furthermore, patients on L-thyroxine treatment and restored euthyroidism had generally higher HRV values than patients with subclinical hypothyroidism, nevertheless SDNN, RMSSD, SDNN index, TINN, and mean RR were significantly lower when compared to those of the control group. Significant differences in HRV were also found between hyperthyroid patients under treatment and control group subjects with respect to RMSSD, TINN, and mean RR values. In conclusion, patients with cardiac disease and known thyroid disease, even when the disease is in the subclinical range or despite treatment, should be regarded as patients at additional risk conveyed by thyroid hormone disturbances.

Possible role of -374T/A polymorphism of RAGE gene in longevity

Demographic and social changes in the last decades have resulted in improvements in health and longevity. The survival of elderly people has improved significantly and thus centenarians are becoming the fastest growing population group. Environmental, genetic, and accidental factors have influenced the human life span. Researchers have gained substantial evidence that advanced glycation end products may play an important role in the processes of physiological aging. The aim of the present study was to investigate any differences in the frequencies of –374T/A polymorphism in subjects aged >90 years and in middle-aged individuals. We observed association between the A allele and genotype homozygous for this allele (AA) with a longer life expectancy in the male population. In particular, there was a prevalence of AA genotype and A allele in long-living subjects and a prevalence of the allele T in middle-aged subjects, indicating a possible protective role of the allele A to aging. In conclusion, our results support the hypothesis that longevity is the result of a good functioning of the immune system and a presumable hyper-expression of variants of anti-inflammatory genes of immunity. The differences in the genetic regulation of inflammatory processes may influence the presence of age-related disorders.

RAGE gene polymorphism in heart failure patients with and without angiographic evidence of significant coronary atherosclerosis

Heart failure (HF) is a multifactorial disorder in which clinical, environmental and genetic components take part. For this reason it is possible that common gene variants could affect development, progression and response to pharmacological therapy. In recent years the role of AGEs in the pathogenesis of cardiovascular diseases has become recognized but little is known about the role of the AGE–RAGE system in heart failure. The aim of the present study was to identify possible relationship between -374 T/A RAGE gene polymorphism with heart failure. The population in this study consists of 386 subjects with HF, selected according to the presence of depressed Left Ventricular Ejection Fraction (LVEF) less than45 percent, and 639 patients with CAD documented at coronary angiography. Within the population with HF there are 228 patients with disease secondary to not ischemic cause and 158 with post-ischemic condition. The sample of AA genotype was significantly lower in patients with post-ischemic HF in respect to HF secondary to non-ischemic causes (pless than0.001). A significant difference between the two groups was also observed regarding the allele frequency. In addition, differences in the allelic and the genotypic frequencies of homozygous genotypes were found between the HF patients free from evidence of coronary significant lesions and patients with at least one hemodynamically significant coronary lesion, both HF and CAD. In patients with at least one vessel compromised the presence of A allele and the homozygous AA genotype were significantly lower than in patients with lesion-free coronary. In conclusion, our research reveals that the -374 T/A polymorphism is related to the genesis of atherosclerotic coronary artery disease but not to its evolution. The protective role of AA genotype in respect to atheromatous disease is therefore confirmed also in the HF population with non-ischemic origin.

Primary headache and silent myocardial ischemia in patients with coronary artery disease

OBJECTIVE

The mechanisms by which migraine is linked to ischemic vascular disease remain uncertain and are likely to be complex. The aim of this study was to investigate the correlation between silent myocardial ischemia (SMI) and a history of documented primary headache in a large population of patients with exercise-induced myocardial ischemia.

METHODS

The study involved 1,427 consecutive patients (918 symptomatic and 509 asymptomatic patients) with exercise-induced myocardial ischemia and documented coronary artery disease (CAD).

RESULTS

Patients with anginal symptoms during exercise-induced myocardial ischemia had a significantly higher prevalence of primary headache than those without (41 vs. 30%, p < 0.001). Patients with angina pectoris in daily life also had greater prevalence of primary headache than those without anginal symptoms (37 vs. 20%; p < 0.0001). Symptomatic patients during percutaneous transluminal coronary angiography or myocardial infarction had a greater prevalence of primary headache than asymptomatic patients (p < 0.001 and p = 0.005, respectively).

CONCLUSIONS

Our data suggest that a history of headache in CAD population is correlated to a high probability of anginal symptoms and a decreased probability of SMI. The anamnestic absence of headache requires a close monitoring for patients with risk factors for CAD, because this population seems to have a lower susceptibility to pain and the risk of developing SMI might be increased.

Association between two polymorphisms in the HLA-G gene and angiographic coronary artery disease

Atherosclerosis and related complications still represent the major cause of morbidity and mortality in industrialized countries. Therefore, it is particularly important to investigate the molecules involved in cardiac inflammation. Evidence exists showing that the human leukocyte antigen‑G (HLA-G) gene tissue expression and related protein physiological significance is influenced by two polymorphisms, rs16375 and rs1632933. In this study, allelic, genotypic and haplotypic frequencies of a 14-bp insertion/deletion (Ins/Del) (rs16375) and of rs1632933 polymorphisms of the HLA-G gene were investigated in 664 patients with coronary artery disease (CAD) and 345 matched controls by polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis and real-time PCR. The frequency of the Ins/Ins genotype was significantly higher in patients with CAD compared to the controls (P=0.018). After analysis of confounding variables, the results showed that the homozygous Ins/Ins was significantly and independently associated with the presence of angiographic CAD (odds ratio 2.09, 95% confidence interval 1.10-4.02, P=0.03). Our data demonstrate a new risk factor for this multifactorial inflammatory disease.

Galectin-3 plasma levels and coronary artery disease: a new possible biomarker of acute coronary syndrome

Inflammation plays a key role in atherosclerosis. Galectin-3 is a macrophage- and endothelium-derived mediator actively involved in the regulation of many aspects of inflammatory cell behaviour. The aim of this study is to quantify plasma Galectin-3 in patients with coronary artery disease (CAD) and different clinical manifestation at the moment of observation in order to verify whether Galectin-3 could be a useful biomarker of atherosclerotic state. We enrolled 125 patients affected by CAD, angiographically documented (70 stable, 55 unstable). They underwent accurate examinations and anamnestic data was collected. The most important traditional risk factors, such as age, hypertension, and body mass index, were reported. Plasma Galectin-3 was quantified using an ELISA kit. Unstable patients (n = 55) had a higher plasma Galectin-3 levels in respect to the stable subjects (27.75 ng/mL (19.27-39.09) vs 6.48 ng/ml (4.88-8.83), p&#x003C;0.001. A trend in correlation between plasma Galectin-3 levels and number of vessels compromised seems to be present: CAD patients with three-vessel disease had higher levels of Galectin-3 than patients with one-or two-vessel disease (17.39 ng/ml (10.75-29.82) vs 9.18 ng/ml (5.56-23.22), p= 0.058. The significantly higher plasma Galectin-3 levels in patients with unstable angina in respect to the stable angina confirm the involvement of Galectin-3 in promoting macrophage activation and monocyte attraction. Despite the distribution of CAD in patients with acute and chronic coronary disease being similar, we may hypothesize that Galectin-3 could be a useful biomarker of atherosclerotic plaque and in particular of its destabilization.

APJ polymorphisms in coronary artery disease patients with and without hypertension

Apelin is an endogenous peptide that increases cardiac inotropism through its APJ receptor. Certain findings indicate that the apelinergic system may have a pathophysiological role in cardiovascular disease and there is evidence showing the role of the apelinergic system in blood pressure regulation in vitro and in animal models. The role of the apelin-APJ system in cardiovascular physiology and its interaction with other neuroendocrine pathways has not been fully elucidated. However, the small number of reported studies indicates that apelin signaling may be involved in the regulation of blood pressure, cardiac contractile function, fluid balance, angiogenesis and inhibition of apoptosis. We evaluated the possible relationship between the G212A and A445C APJ polymorphisms and coronary artery disease (CAD) in Italian patients and in healthy controls by RFLP-PCR. We analyzed the allelic and genotypic frequencies of APJ polymorphisms in 664 patients (378 with hypertension) and 143 controls. There were no differences between allelic and genotypic frequencies in patients in respect to the controls for both polymorphisms analyzed. In the CAD population, there was an increased frequency of the G212 allele in patients with hypertension in respect to patients without hypertension. No differences were present in the two subgroups for the A445C polymorphism. Although the functional role of the G212A polymorphism has not yet been identified, it is possible to hypothesize that the presence of the A allele may cause a gain in function of the apelin/APJ system associated with a lower risk of hypertension.

Excess of activating killer cell immunoglobulin‑like receptors and lack of HLA-Bw4 ligands: a two‑edged weapon in chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is an inflammatory disease of unknown aetiology. Researchers have proposed infectious, neurological and immunological causes of this syndrome. Recently, the xenotropic murine leukemia virus-related virus was detected in 67% of patients with CFS in a US study. This observation is in agreement with one ascertained aspect of the disease: a decreased efficiency in NK cell lytic activity in CFS patients. Here, we analyzed the genomic polymorphism of killer cell immunoglobulin-like receptors (KIRs) and their HLA class I cognate ligands in patients with certified CFS. An excess of KIR3DS1 was found in CFS patients with respect to controls, as well as an increased frequency of the genotype missing KIR2DS5. Forty-four CFS patients and 50 controls also underwent genomic typing for the HLA-ligands. In the patients, a great proportion of KIR3DL1 and KIR3DS1 receptors were found to be missing their HLA-Bw4Ile80 binding motif. We hypothesize that an excess of KIR3DS1, combined with an excess of ligand-free KIR3DL1 and KIR3DS1 receptors, may hamper the clearance of a pathogen via NK cells, thus favouring the chronicity of the infection.

Age of onset of myocardial infarction: is promoter polymorphism of the RAGE gene implicated?

Receptor for advanced glycation endproducts (RAGE) is a cell-surface molecule member of the immunoglobulin superfamily and engages differing ligands relevant to distinct processes. A growing body of evidence has suggested that RAGE may promote vascular inflammation through several mechanisms. The objective of this study was to identify the possible relationship between the -374 T/A polymorphism of the RAGE gene, myocardial infarction (MI), and its age of onset. A total of 691 MI patients and 234 matched controls were investigated. In this study, the frequency of the A allele and AA genotype of the -374 T/A promoter polymorphism is significantly lower in patients with MI respect to the control group (p < 0.01). Our results showed a significant role of the AA genotype on age of onset of MI. In particular, the mean age of the first MI was higher in patients with the AA genotype as compared to those that were AT or TT genotype carriers (p = 0.002). The relationship between -374 T/A RAGE polymorphism and age for the appearance of MI was independently related to common risk factors of disease (p < 0.01). Kaplan-Meier curves confirmed that subjects with the AA genotype have a later development of MI (p = 0.0022). This study is the first to investigate the role of RAGE polymorphisms on the susceptibility to develop the acute coronary events in the Italian population and identified this polymorphism as an age-related factor for MI development. The homozygous AA genotype may exert a protective role against the early development of MI.

Coronary artery disease and depression: possible role of brain-derived neurotrophic factor and serotonin transporter gene polymorphisms

Cardiovascular disease (CVD) and depression are two of the most common human health problems. Patients with depression have an increased risk of developing cardiovascular disease and mortality after experiencing a cardiac event. Both diseases are complex disorders that are influenced by genetic and environmental factors. Brain-derived neuro-trophic factor (BDNF) plays a critical role in regulating both vascular development and response to injury, and promotes survival, differentiation, and maintenance of neurons in the peripheral and nervous system. Evidence suggests that BDNF can enhance serotoninergic transmission. Serotonin modulates different brain functions and is known to regulate sleep, appetite, pain and inflammation. The aims of the present case-control study were to investigate the possible role of BDNF Val66Met, 5-HTTLPR and -1438 G/A polymorphisms in the development of coronary artery disease (CAD) in patients with and without depression. Regarding BDNF, our data suggest an involvement of the AA genotype in the pathogenesis of CAD in females and in the predisposition to CAD associated with depression. Furthermore, it could be argued that the GG genotype is protective against CAD in the female population and against CAD associated with depression. In our CAD population we also observed a significant increase in the L/L genotype and a decrease in the S/L genotype with respect to the controls. A higher frequency of the L allele, responsible for enhancing the efficiency of transcription, was found in CAD patients. These findings may be responsible for the increased capacity of platelet serotonin uptake previously observed in patients with CAD. Although no differences were found for genotype and allelic frequencies of the -1438 G/A polymorphism between the CAD patients and controls, we cannot exclude the possible role of this receptor in coronary artery disease.

Autoantibodies, polymorphisms in the serotonin pathway, and human leukocyte antigen class II alleles in chronic fatigue syndrome: are they associated with age at onset and specific symptoms?

This study aimed to determine the influence of autoantibodies, polymorphisms in the serotonin pathway, and human leukocyte antigen (HLA) class II genes on age at chronic fatigue syndrome (CFS) onset and symptoms. Eighty-one CFS patients were enrolled, and clinical data were recorded. Autoantibodies to different components of the central nervous system were tested. Polymorphisms in the promoter of the serotonin transporter gene (l/s) and a single nucleotide polymorphism in the serotonin receptor-2A gene (A/G) as well as HLA class II alleles were determined. Multivariate logistic-regression analyses were carried out. The mean age at CFS onset +/- SD was 33.5 +/- 12.5 years. An age at CFS onset (ACFSO) during the third decade of life was associated with the serotonin receptor AA genotype and the HLA-DRB1*03 allele. An ACFSO during the fourth decade of life was associated with the HLA-DRB1*07 allele, whereas an ACFSO > or = 43 years was associated with having at least one copy of the serotonin G allele. Concerning CFS symptoms, the serotonin AG genotype was protective against depressive symptoms. Although having at least one copy of the serotonin A allele and being female were associated with risk for arthralgia, the presence of antineuronal cell antibodies was protective against this. Episodes of unexplained fever were associated with the HLA-DRB1*11 allele. None of the genetic or serological features was associated with myalgia. None of the antibodies determined correlated with any ACFSO or other symptoms. Our results reveal that in CFS, like other autoimmune diseases, different genetic features are related to age at CFS onset and symptoms.

Molecular Study of Receptor for Advanced Glycation Endproduct Gene Promoter and Identification of Specific HLA Haplotypes Possibly Involved in Chronic Fatigue Syndrome

The receptor for advanced glycation end product (RAGE) is thought to play an important role in inflammation. Chronic Fatigue Syndrome (CFS) is a long-lasting fatigue that compromises at least 50% of a subject's daily activities without other known cause. Immune dysfunction has been implicated and an association with a peculiar genetic cytokine profile, predisposing to an immunomodulatory response of inflammatory nature, was found. The aim of this study is to analyse RAGE polymorphisms and HLA-DRB1 alleles in seventy-five Italian CFS patients and 141 controls matched for age, sex and ethnicity. These two groups underwent genomic study for RAGE –374T/A and –429C/T promoter polymorphisms; moreover, 46 patients and 186 controls were typed for HLA-DRB1 at low resolution molecular level. Of these, 31 patients and 99 controls also underwent “high resolution analysis” to define the HLA-DRB1*11 and DRB1*13 alleles. The haplotypes RAGE-374T, DRB1*04; RAGE-374T, DRB1*09; RAGE-374T, DRB1*11; RAGE-374A, DRB1*13; RAGE-429T, DRB1*04 and RAGE-429C, DRB1*11 were significantly more frequent in CFS patients, whereas RAGE-429C, DRB1*07 would seem protective. A significantly lower frequency of DRB1*1104 (5.4% vs 12.9% p=0.04, OR=0.39) and a significantly higher frequency of HLA-DRB1*1301 (13.0% vs 5.1% p=0.006, OR= 2.79) were found in CFS patients. A synergic effect was observed with RAGE polymorphism. The OR values strengthened in the following cis combinations: RAGE-374A, HLA-DRB1*1104 (OR=0.27) and RAGE-374A, HLA-DRB1*1301 (OR=6.23). HLA haplotypes rather than single alleles of RAGE or of DRB1 genes seem to be involved in CFS, probably including a subregion of major interest.

Antibacterial activity of zinc modified titanium oxide surface

Titanium-based implants are successfully used for various biomedical applications. However, in some cases, e.g. in dental implants, failures due to bacterial colonization are reported. Surface modification is a commonly proposed strategy to prevent infections. In this work, titanium oxide, naturally occurring on the surface of titanium, was modified by promoting the formation of a mixed titanium and zinc oxide, on the basis of the idea that zinc oxide on titanium surface may act as the zinc oxide used in pharmaceutical formulation for its lenitive and antibacterial effects. The present work shows that it is possible to form a mixed titanium and zinc oxide on titanium surfaces, as shown by Scanning Electron Microscopy and XPS analysis. To this end titanium was preactivated by UV on crystalline titanium oxide, both in the anatase form or in the co-presence of anatase and rutile. By performing antibacterial assays, we provide evidence of a significant reduction in the viability of five streptococcal oral strains on titanium oxide surfaces modified with zinc. In conclusion, this type of chemical modification of titanium oxide surfaces with zinc might be considered a new way to reduce the risk of bacterial colonization, increasing the lifetime of dental system applications.

Heparin-binding domain of human fibronectin binds HIV-1 gp120/160 and reduces virus infectivity

In vitro experiments indicate that components of the host present in body fluids may prevent the attachment of human immunodeficiency virus type 1 (HIV-1) to target cells. Fibronectin (Fn), a dimeric 440-kDa extracellular matrix adhesion protein, is secreted by mesenchymal cells and assembled into insoluble matrices. Fn exerts important effects on cell growth and differentiation through a number of discrete functional domains. Several microorganisms are known to bind Fn. We show that, under physiological conditions, HIV-1 gp120 and gp160 are capable of binding plasma and cellular Fn as well as laminin and vitronectin. Experiments were set up to analyze in detail the binding of HIV gp120 and gp160 to Fn. The gp120 and gp160 specifically recognize the C-terminal heparin-binding domain of Fn (Fn-CTHBD) with a calculated KD of 2.8 x 10(-7) M for gp160. Binding of gp160 to Fn-CTHBD is a saturable and specific process that is blocked by antibodies to Fn-CTHBD and by heparin and is inhibited to a minor extent by heparan sulfate and dextran sulfate. These observations suggest that gp120/160 specifically recognize the III15 repeat within Fn-CTHBD. Intact Fn and Fn-CTHBD strongly inhibit the interaction of gp120/160 with soluble CD4 and, under low serum conditions, are capable of neutralizing the infectivity of HIV-1 for CD4-positive T cells. Thus, Fn that is present in plasma and mucinous secretions may well affect HIV infectivity and virus distribution in vivo.

A monoclonal antibody enhances ligand binding of fibronectin MSCRAMM (adhesin) from Streptococcus dysgalactiae

A monoclonal antibody 3A10, generated from a mouse immunized with the Streptococcus dysgalactiae fibronectin (Fn) binding protein FnbA, was isolated, and its effect on ligand binding by the antigen was examined. The epitope for 3A10 was localized to a previously unidentified Fn binding motif (designated An) just N-terminal of the repeat domain which represents the primary ligand binding site on FnbA. Fn binding to Au was enhanced by 3A10 rather than inhibited. This effect was demonstrated in two different assays. First, in the presence of 3A10 the Au-containing proteins and synthetic peptide more effectively competed with bacterial cells for binding to Fn. Second, 3A10 dramatically increased the binding of biotin-labeled forms of the Au-containing proteins to Fn immobilized on a blotting membrane. Pure 3A10 IgG did not recognize the antigen by itself, and Fn was required for the immunological interaction between the antibody and the epitope. This induction effect of Fn was shown in both Western blot and enzyme-linked immunosorbent assay in which immobilized Au-containing molecules were probed with 3A10 in the presence of varying concentrations of Fn. Specificity analyses of 3A10 revealed that the monoclonal also recognized a ligand binding motif in a Streptococcus pyogenes Fn binding MSCRAMM but not the corresponding motifs in two related adhesins from Staphylococcus aureus and S. dysgalactiae. Furthermore, 3A10 stimulated Fn binding by S. pyogenes cells. These results together with subsequent biophysical studies presented in the accompanying paper (House-Pomepeo, K., Xu, Y., Joh, D., Speziale, P., and Höök, M. (1996) J. Biol. Chem. 271, 1379-1384) indicate that the ligand binding sites of Fn binding MSCRAMMs have little or no secondary structure. However, on binding to Fn, they appear to undergo a structural rearrangement resulting in a defined structure rich in beta sheet and expressing a ligand-induced binding site for antibodies such as 3A10.

Isolation and characterization of a novel collagen-binding protein from Streptococcus pyogenes strain 6414

In this report we have analyzed the binding of collagen to Streptococcus pyogenes strain 6414. This binding was rapid, specific, and involved a limited number of receptor molecules (11,600 copies per cell). When the proteins in a streptococcal lysate were blotted onto a nitrocellulose filter and probed with 125I-labeled collagen, a prominent collagen-binding protein of 57 kDa was identified as well as minor 130-150-kDa components. The major 57-kDa protein was isolated by affinity chromatography on collagen-Sepharose followed by gel filtration chromatography. The 57-kDa protein purified from S. pyogenes was used to raise a monospecific antibody which also reacted with a collagen-binding protein of similar molecular size isolated from Streptococcus zooepidemicus. The two collagen-binding proteins from streptococci have a similar amino acid composition and isoelectric points. Isolated collagen-binding protein was specifically recognized by 125I-collagen in a solid-phase binding assay and displayed an affinity for the ligand quite similar to that exhibited by intact bacteria (Kd = 3.1 versus 3.5 x 10(-9) M, respectively). Surface-labeled bacteria attached to microtiter wells coated with different collagen types and the 57-kDa protein blocked the adhesion to collagen substrate. We propose that the 57-kDa protein is an adhesin involved in the attachment of streptococci to host tissues.

Multiple binding sites in fibronectin and the staphylococcal fibronectin receptor

The binding of fibronectin to Staphylococci exhibits the properties of a ligand-receptor interaction and has been proposed to mediate bacterial adherence to host tissues. To localize staphylococcal-binding sites in fibronectin, the protein was subjected to limited proteolysis and, of the generated fragments, Staphylococci appeared to preferentially bind to the N-terminal fragment. Different fibronectin fragments were isolated and tested for their ability to inhibit 125I-fibronectin binding to Staphylococci. The results indicate that only the N-terminal region effectively competed for fibronectin binding. However, when isolated fragments were adsorbed to microtiter wells, we found that two distinct domains, corresponding to the N-terminal fragment and to the heparin-binding peptide mapping close to the C-terminal end of fibronectin, promoted the attachment of both Staphylococcus aureus Newman and coagulase-negative strain of Staphylococcus capitis 651. These same domains were recognized by purified 125I-labeled staphylococcal receptor, either when immobilized on microtiter wells or probed after adsorption onto nitrocellulose membrane. The heparin-binding domain is comprised of type-III-homology repeats 14, 15 and 16. To determine which repeats participate in this interaction, we isolated and tested repeats type III14 and type III16. We found that the major staphylococcal binding site is located in repeat type III14. The staphylococcal receptor bound the N-terminal domain of fibronectin with a KD of 1.8 nM, whereas the dissociation constant of the receptor molecule for the internal heparin-binding domain was 10 nM. Since the fusion protein ZZ-FR, which contains the active sequences of fibronectin receptor (D1-D3) bound only to the N-terminus, it is reasonable to assume that the bacterial receptor may have additional binding sites outside the D domains, capable of interacting with the internal heparin-binding domain of fibronectin.

Cloning and expression of two different genes from Streptococcus dysgalactiae encoding fibronectin receptors

Binding of bacteria to fibronectin has been implicated as a mechanism of bacterial adhesion to the host tissue. In this report we have analyzed the binding of a strain of Streptococcus dysgalactiae to fibronectin. The cells bind to a site in the NH2-terminal domain of the protein via trypsin-sensitive cell surface components. Furthermore, a lysate prepared by sonication of streptococcal cells contained fibronectin-binding proteins that inhibit the binding of the ligand to intact bacteria. When the proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, blotted to an Immobilon-P filter, and probed with 125I-labeled fibronectin, a 140-kDa fibronectin-binding protein was identified along with a number of smaller binding proteins. A genomic DNA library was constructed and screened for the expression of fibronectin-binding proteins. Two clones were isolated and shown to contain unrelated inserts by restriction mapping and cross-hybridization experiments. The two encoded proteins were also immunologically distinct although both bound to the same region of the fibronectin molecule, and both effectively inhibited the binding of 125I-fibronectin to bacterial cells. Immunological analyses showed that only one of the two proteins tentatively identified as fibronectin receptors was expressed in detectable quantities in the Streptococcus dysgalactiae strain under the culture conditions employed.

Binding sites in fibronectin for an enterotoxigenic strain of E. coli B342289c

The binding of fibronectin and fibronectin fragments to the enterotoxigenic strain E. coli B34289c was studied. E. coli cells bound to two distinct sites of fibronectin, one being the N-terminal domain, which also contains the binding sites for staphylococci and streptococci, and the other located within the central heparin binding region. In addition, the N-terminal and the heparin binding domain mediated the attachment of bacteria in a solid phase binding assay. E. coli cells expressed two classes of receptors, the first, a 17 kDa protein, recognized by the N-terminal fragment and the second, having a mol. mass of 55 kDa, which interacts with the internal heparin binding domain. Bacterial receptors, which bind the N-terminal end of fibronectin, may be structurally related.

Binding of collagens to an enterotoxigenic strain of Escherichia coli

An enterotoxigenic strain of Escherichia coli, B34289c, has been shown to bind the N-terminal region of fibronectin with high affinity (G. Fröman, L. M. Switalski, A. Faris, T. Wadström, and M. Höök, J. Biol. Chem. 259:14899-14905, 1984). We now report that this strain also binds collagen. The binding of 125I-labeled type II collagen to bacteria was time dependent and reversible. Bacteria expressed a limited number of collagen receptors (2.2 x 10(4) per cell) and bound collagen with a Kd of 20 nM. All collagen types tested (I to V) as well as all tested cyanogen bromide-generated peptides [alpha 1(I)CB2, alpha 1(I)CB3, alpha 1(I)CB7, alpha 1(I)CB8, and alpha 2(I)CB4] were recognized by bacterial receptors, as demonstrated by the ability of these proteins to inhibit the binding of 125I-labeled collagen to bacteria. Of several unlabeled proteins tested in competition experiments, fibronectin and its N-terminal region strongly inhibited binding of the radiolabeled collagen to E. coli cells. Conversely, collagen competed with an 125I-labeled 28-kilodalton fibronectin fragment for bacterial binding. Collagen bound to bacteria could be displaced by excess amounts of either unlabeled fibronectin or its N-terminal fragment. Similarly, collagen could displace 125I-labeled N-terminal peptide of fibronectin bound to the bacterial cell surface. Bacteria grown at 41 degrees C or in the presence of glucose did not express collagen or fibronectin receptors. These results indicate the presence of specific binding sites for collagen on the surface of E. coli cells and furthermore that the collagen and fibronectin binding sites are located in close proximity, possibly on the same structure.

Chlorpropamide-alcohol flushing in non insulin-dependent diabetes: prevalence of small and large vessel disease and or risk factors for angiopathy

One hundred and eight non insulin-dependent diabetics were tested for alcohol flushing after chlorpropamide administration (CPAF test). The overall prevalence of patients who flushed at the first challenge was 32%. However, nearly half of them still flushed after alcohol administration, when placebo was given instead of chlorpropamide, so that the prevalence of 'true' flushers was only 17%. Even though the distribution of retinal lesions was similar in 'true' flushers and in non flushers, severe loss of visual acuity was confined to the non flushers and aspecific flushers. The frequency of pathological ECG findings and of peripheral pulse reduction or abolition was significantly higher in the non flushers and aspecific flushers. Blood pressure, serum lipids and hemostatic parameters were similar in the two groups, and therefore do not explain the differences in prevalence of lesions. This study confirms the previous findings of a lower prevalence of large vessel lesions in flushers; however, the prevalence of 'true' CPAF phenomenon in our out-patient population appears to be much lower than previously reported.