Chlamydia pneumoniae and osteoporosis-associated bone loss: a new risk factor?

UNLABELLED: We found an association between the presence of Chlamydia pneumoniae DNA both in osteoporotic bone tissue and peripheral blood mononuclear cells (PBMCs) and the increase in circulating resorptive cytokines. INTRODUCTION: Our study was designed to determine whether C. pneumoniae infection may be involved in osteoporosis-associated bone loss. METHODS: The study included 59 women undergoing hip joint replacement surgery for femoral neck fracture: 32 with osteoporosis and 27 with osteoarthritis. A total of 118 tissue specimens (59 bone tissues, 59 PBMCs) were examined for C. pneumoniae DNA by real-time polymerase chain reaction (PCR). Serum levels of soluble receptor activator of nuclear factor kappa B ligand (sRANKL), osteoprotegerin (OPG), interleukin (IL)-1ß, tumor necrosis factor-α, and IL-6 were also measured. RESULTS: C. pneumoniae DNA was detected in osteoporotic bone tissue whereas it was not found in non-osteoporotic bone tissue (p < 0.05). A significantly higher rate of C. pneumoniae DNA (p < 0.05) was found in PBMCs of osteoporotic patients than in those of osteoarthritis patients. Among osteoporotic patients, serum sRANKL, IL-1, and IL-6 concentrations as well as sRANKL/OPG ratio significantly differ between patients with bone tissue and PBMCs positive to C. pneumoniae and C. pneumoniae-negative patients. CONCLUSION: The association between the presence of C. pneumoniae DNA, both in bone tissue and PBMCs, and the increase in sRANKL/OPG ratio as well as in IL-1ß and IL-6 levels observed in osteoporotic patients suggests C. pneumoniae infection as a new risk factor for osteoporosis.

Resveratrol in Chlamydia pneumoniae-induced foam cell formation and interleukin-17A synthesis.

The involvement of Chlamydia pneumoniae in the pathogenesis of atherosclerosis has been suggested by numerous seroepidemiological, in vivo and in vitro studies. In particular, it has been shown that C. pneumoniae is able to promote the accumulation of low-density lipoproteins into macrophages, thus facilitating foam cell formation. The aim of our study was to investigate the effects of resveratrol on macrophage derived foam cell formation induced by C. pneumoniae, examining its underlying biochemical mechanisms. Our results showed a relevant decrease in the number of foam cells, in the production of thiobarbituric acid reactive substances, superoxide anion and IL 17A while treating C. pneumoniae infected macrophages with resveratrol. Furthermore, the inhibition of Peroxisome Proliferator-Activated Receptors gamma by a specific antagonist (GW 9662), in presence of resveratrol and C. pneumoniae, enhanced intracellular lipid and cholesterol accumulation and the subsequent foam cell formation. In conclusion, the main result of our study is the evidence of an antiatherogenic effect of resveratrol on macrophage-derived foam cell formation and IL-17A production induced by C. pneumoniae.

Analysis of gene expression in penicillin G induced persistence of Chlamydia pneumoniae.

Chlamydia pneumoniae is responsible for respiratory tract infections and has been associated to chronic diseases such as atherosclerosis. The involvement of C. pneumoniae in chronic diseases may be correlated to its ability to induce persistent forms in which Chlamydiae remain viable but are not cultivable. The aim of our study is to investigate C. pneumoniae specific gene activities associated with the development of Chlamydial persistence in a cell culture system in the presence of penicillin G. Chlamydia-infected HEp 2 cells were incubated with or without penicillin G for up to 72 hours. The relative mRNA expression levels of early and late genes in treated and untreated cell cultures were determined by Real-time RT-PCR. Our results revealed a consistent down-regulation of Chlamydial hctA and hctB genes (p=0.012 and p=0.003 respectively) in association with up-regulation of htrA gene (p=0.002) during penicillin G-induced persistence suggesting these gene sets as leading candidate for in vivo investigation of the development of persistent Chlamydial infection. In conclusion, the Chlamydial expression pattern of hctA, hctB, and htrA genes may be helpful to identify target molecules to diagnose and treat Chlamydia-associated chronic diseases.

Chlamydia pneumoniae infection as a risk factor for accelerated atherosclerosis in hemodialysis patients.

Atherosclerotic cardiovascular disease is the main cause of morbidity and mortality for end-stage renal disease patients undergoing chronic haemodialysis (HD). Several studies in recent years have identified Chlamydia pneumoniae, a respiratory pathogen, as risk factor for cardiovascular diseases in the general population. The aim of our study is to evaluate chlamydial load, in peripheral blood mononuclear cells (PBMC) of HD patients. Furthermore, the correlation between DNA chlamydial load and markers of inflammation was also examined. PBMC specimens isolated from 49 HD patients and 46 blood donors were analyzed for the presence of C. pneumoniae DNA by real-time PCR and ompA nested touchdown PCR. In HD patients, plasma levels of several inflammatory markers were also determined. A significantly higher rate of C. pneumoniae DNA was found in HD patients (44.9 percent) than in blood donors (19.6 percent) (p=0.016); HD patients were also more likely to have a significantly high chlamydial load (p=0.0004). HD patients with atherosclerotic cardiovascular diseases have a significantly greater chlamydial load than HD patients without cardiovascular diseases (p= 0.006). A significantly higher value of C-reactive protein, IL-6 and advanced oxidative protein products was found in HD patients with a greater chlamydial load (p less than 0.05). Likewise, a significantly lower monocyte HLA-DR percentage (p=0.011) as well as a lower monocyte HLA-DR expression were found in such patients (p= 0.007). In conclusion, our results show that HD patients are at high risk of C. pneumoniae infection correlated with chronic inflammatory response which in turn can lead to accelerated atherosclerosis and other long-term clinical complications such as myocardial infarction and stroke.

Accelerating the experimental responses on cell behaviors: a long-term prediction of cell trajectories using Social Generative Adversarial Network.

The incremented uptake provided by time-lapse microscopy in Organ-on-a-Chip (OoC) devices allowed increased attention to the dynamics of the co-cultured systems. However, the amount of information stored in long-time experiments may constitute a serious bottleneck of the experimental pipeline. Forward long-term prediction of cell trajectories may reduce the spatial-temporal burden of video sequences storage. Cell trajectory prediction becomes crucial especially to increase the trustworthiness in software tools designed to conduct a massive analysis of cell behavior under chemical stimuli. To address this task, we transpose here the exploitation of the presence of "social forces" from the human to the cellular level for motion prediction at microscale by adapting the potential of Social Generative Adversarial Network predictors to cell motility. To demonstrate the effectiveness of the approach, we consider here two case studies: one related to PC-3 prostate cancer cells cultured in 2D Petri dishes under control and treated conditions and one related to an OoC experiment of tumor-immune interaction in fibrosarcoma cells. The goodness of the proposed strategy has been verified by successfully comparing the distributions of common descriptors (kinematic descriptors and mean interaction time for the two scenarios respectively) from the trajectories obtained by video analysis and the predicted counterparts.

Chlamydia pneumoniae and atherosclerosis: current state and future prospectives.

Chlamydia pneumoniae, an intracellular bacterial pathogen, is known as a leading cause of human respiratory tract infections worldwide. Over the last decade, several reports in the literature have suggested that infection with C. pneumoniae may contribute to the pathogenesis of atherosclerosis. In order to play a causative role in chronic disease, C. pneumoniae would need to persist within infected tissue for extended periods of time, thereby stimulating a chronic inflammatory response. C. pneumoniae has been shown to disseminate systemically from the lungs through infected peripheral blood mononuclear cells and to localize in arteries where it may infect endothelial cells, vascular smooth muscle cells, monocytes/macrophages and promote inflammatory atherogenous process. The involvement of C. pneumoniae in atherosclerosis was investigated by seroepidemiological and pathological studies, in vivo and in vitro studies, and in clinical antibiotic treatment trials. This review will provide an update on the role of C. pneumoniae in atherosclerosis focusing on the recent insights and suggesting areas for future research.

Chlamydia pneumoniae induces T cell apoptosis through glutathione redox imbalance and secretion of TNF-alpha.

Chlamydia pneumoniae persistent infection has been implicated in the pathogenesis of several chronic inflammatory diseases including atherosclerosis, and we hypothesized that modulation of the apoptosis of macrophages and/or T cells by C. pneumoniae infection may contribute to the development of such diseases. We therefore evaluated apoptosis, cytokine response, and redox status in human primary T cells and macrophages infected with C. pneumoniae. In addition, co-cultures of T cells and macrophages infected with C. pneumoniae were also carried out. Apoptosis, and levels of glutathione (GSH), glutathione disulfide (GSSG), and tumour necrosis factor (TNF)-alpha were measured by flow cytometry, high performance liquid chromatography and enzyme-linked immunosorbent assay. C. pneumoniae induced apoptosis in T cells as well as in co-cultures of T cells and infected macrophages by marked decrease in GSH/GSSG ratio and increased production of TNF-alpha, respectively. The results demonstrate that interaction of C. pneumoniae with T cells and/or macrophages characterized by interference with redox status, and secretion of tumour necrosis factor-alpha culminates in the induction of T cell apoptosis and survival of infected macrophages. In conclusion, the inappropriate T cell response against C. pneumoniae and survival of infected macrophages could explain the persistence of this intracellular obligate pathogen in the host-organism; it may contribute to the development of chronic inflammatory diseases, although further studies are needed to clarify such a complex mechanism.

Chlamydia pneumoniae and atherosclerosis: the role of mast cells.

Chlamydia pneumoniae (C. pneumoniae), a respiratory pathogen, has been implicated in the pathogenesis of atherosclerosis, an inflammatory progressive disease, characterized by the formation of atherosclerotic plaques. Among several types of inflammatory cells involved in the atherogenesis process, recently particular attention has been directed toward the mast cells. Experimental studies have provided several mechanisms by which C. pneumoniae and mast cells could play a role in all stages of atherosclerosis, from initial inflammatory lesions to plaque rupture. C. pneumoniae, as well as mast cells, may actively participate both through the production of cytokines and matrix-degrading metalloproteinases and by provoking apoptosis of atheroma-associated vascular cells, key events in plaque rupture. This mini-review provides a brief overview on adventitial inflammatory effects of C. pneumoniae and mast cells and their potential role in plaque instability. In addition, in this paper we review the role of mast cells in innate immunity.

No evidence of involvement of Chlamydia pneumoniae in lung cancer by means of quantitative real-time polymerase chain reaction.

Chlamydia pneumoniae, an obligate intracellular pathogen, is well-known as etiological agent of acute respiratory infections; the repeated or prolonged exposure to chlamydial antigens may promote the persistence of C. pneumoniae in the respiratory tract leading to chronic diseases, such as chronic obstructive pulmonary disease and asthma. The predilection of C. pneumoniae to cause respiratory tract infections combined with its persistent nature suggest that it might play a role in lung cancer. The aim of our study is to evaluate the involvement of C. pneumoniae in pathogenesis of lung cancer. We therefore investigated the presence of C. pneumoniae DNA in tumor lung tissues by using real-time PCR assay. Simultaneously, tumor and healthy tissues from the same patient with primary carcinoma lung were analyzed. C. pneumoniae DNA was not detected in a single lung tumor tissue by means of an highly sensitive, and specific real-time PCR assay based on FRET hybridization probes. In conclusion, this study does not support the involvement of C. pneumoniae in the pathogenesis of lung cancer, suggesting that further investigations are needed to clarify other potential causative factors for the development of this malignancy.

Sirolimus, Tacrolimus and Zotarolimus eluting stents to treat bifurcated lesions: a 7-month clinical outcome comparison.

AIM: Drug eluting stents (DES) have been shown to reduce restenosis compared with bare metal stents in bifurcated lesions. The aim of this study was to evaluate the long-term clinical outcomes of patients with bifurcated lesions treated by 3 different DES. METHODS: Consecutive patients with symptomatic coronary artery disease on one bifurcated lesion with SB>2.25 mm (on visual estimation) undergoing at the Department of Cardiology of the Catholic University of Rome, Italy were screened. Patients treated with Sirolimus-eluting stent (Cypher Select; SES Group), Tacrolimus-eluting stent (Taxus-Libertè; TA Group) and Zotarolimus-eluting stent (Endeavor Driver; ZOT Group) were enrolled in the study. Clinical and angiographic characteristics of all patients were prospectively recorded. Major adverse clinical events (MACE), including death, acute myocardial infarction (MI) or target lesion revascularization (TVR) by either percutaneous coronary intervention (PCI) or coronary surgery were recorded during the follow-up. Incidence of definite or probable stent thrombosis was calculated according to the ARC criteria. RESULTS: Two hundred and forty-one consecutive patients were enrolled (89 Group CY, 98 Group TA and 54 Group EN). Length of follow-up was 235+/-60 days. Baseline clinical and angiographic characteristic were similar across the groups. The adopted technique for stent implantation was provisional stenting (73.4%), T-stenting technique (7%), crush (7%) and V-stenting (2.6%). The rate of patients finally treated with two stents was similar among groups. The cumulative rate of MACE (9% SES, 12% TA, 11% ZOT: P=0.7) and of TVR (2% SES, 9% TA, 7% ZOT) was similar among groups. No definite stent thrombosis was observed during follow-up, while 1 probable stent thrombosis was observed in TA group. CONCLUSION: The clinical outcome of bifurcated lesions using DES and mainly a technique of single stent implantation is good. In the present observational study, clinical adverse events did not differ in patients with bifurcated lesions treated by Cypher, Taxus or Endeavor stent implantation.

IRF-1 deficiency skews the differentiation of dendritic cells toward plasmacytoid and tolerogenic features.

Members of the IFN regulatory factors (IRFs) family are transcriptional regulators that play essential roles in the homeostasis and function of the immune system. Recent studies indicate a direct involvement of some members of the family in the development of different subsets of dendritic cells (DC). Here, we report that IRF-1 is a potent modulator of the development and functional maturation of DC. IRF-1-deficient mice (IRF-1(-/-)) exhibited a predominance of plasmacytoid DC and a selective reduction of conventional DC, especially the CD8alpha(+) subset. IRF-1(-/-) splenic DC were markedly impaired in their ability to produce proinflammatory cytokines such as IL-12. By contrast, they expressed high levels of IL-10, TGF-beta, and the tolerogenic enzyme indoleamine 2,3 dioxygenase. As a consequence, IRF-1(-/-) DC were unable to undergo full maturation and retained plasmacytoid and tolerogenic characteristics following virus infection ex vivo and in vivo. Accordingly, DC from IRF-1(-/-) mice were less efficient in stimulating the proliferation of allogeneic T cells and instead, induced an IL-10-mediated, suppressive activity in allogeneic CD4(+)CD25(+) regulatory T cells. Together, these results indicate that IRF-1 is a key regulator of DC differentiation and maturation, exerting a variety of effects on the functional activation and tolerogenic potential of these cells.

Chlamydia pneumoniae in asymptomatic carotid atherosclerosis.

We evaluated, in 415 patients with asymptomatic carotid atherosclerosis: (i) the prevalence of C. pneumoniae DNA in atherosclerotic carotid plaques and peripheral blood mononuclear cells (PBMC); (ii) the distribution of C. pneumoniae in atherosclerotic carotid plaques and PBMC from the same patients; (iii) the correlation between circulating anti-chlamydial antibodies and the presence of C. pneumoniae DNA. Overall, 160 atherosclerotic carotid plaques and 174 PBMC specimens from patients with asymptomatic carotid atherosclerosis were examined by ompA nested touchdown PCR for presence of C. pneumoniae. In addition, C. pneumoniae DNA was detected in 81 specimens of atherosclerotic carotid plaque and PBMC obtained from the same patients. C. pneumoniae DNA was found in 36.9% of atherosclerotic carotid plaques and in 40.2% of PBMC specimens examined (P=NS). With regard to 81 patients, C. pneumoniae DNA was detected in 27.2% of atherosclerotic carotid plaques and in 44.4% of PBMC specimens(P=0.05). In 18 patients, the presence of C. pneumoniae DNA in PBMC specimens and atherosclerotic carotid plaques coincided (P=0.005). No statistically significant association was found between anti-C. pneumoniae antibodies (IgG and IgA) and positive PCR results. In conclusion, our results suggest that the detection of C. pneumoniae DNA in PBMC specimens seems to be a first-choice method to identify the patients at risk for endovascular chlamydial infection.

Chlamydia pneumoniae in PBMC: reproducibility of the OMPA nested touchdown PCR.

The aim of our study was to evaluate whether the replicate PCR testing may provide more accurate estimates of C. pneumoniae DNA prevalence in PBMC of patients undergoing carotid endarterectomy. Clinical sensitivity and reproducibility of ompA nested touchdown PCR was also performed. Clinical sensitivity and reproducibility was examined by testing C. pneumoniae-negative PBMC spiked with serial dilutions of semipurified C. pneumoniae elementary bodies (from 8 to 0.002 IFU/ml). Detection of C. pneumoniae DNA was performed by ompA nested touchdown PCR. Each clinical and spiked PBMC DNA specimen was analyzed in replicates of 1, 3, 5 and 10. PCR results of serial dilutions of C. pneumoniae DNA performed in replicates of 10 were analysed by probit analysis. C. pneumoniae DNA was detected in 14 of the 30 (46.7 %) PBMC clinical specimens examined when 10 replicates were tested. When we analyzed 1, 3 and 5 replicates, 4 (13.3 %), 7(23.3 %), 12(40 %) of the 30 specimens were positive, respectively. The limit of detection of ompA nested PCR touchdown was 0.008 IFU/ml when 10 replicates were tested. The ompA nested PCR had reproducibility scores of 10 for 10 from 8 to 4 IFU/ml concentration, but scores decreased for smaller numbers of IFU/ml. Our results showed that repeat testing of the same specimen increased clinical sensitivity as well as reproducibility of the ompA nested touchdown PCR. In conclusion the replicate PCR testing improves the performance of ompA nested touchdown PCR and provides a more accurate estimates of the prevalence of C. pneumoniae in PBMC of patients with atherosclerotic cardiovascular disease.

Prevalence of Chlamydia pneumoniae in peripheral blood mononuclear cells in Italian patients with acute ischaemic heart disease.

Chlamydia pneumoniae infection generally starts in the respiratory tract and probably disseminates systemically in the blood stream within alveolar macrophages. We investigated the prevalence of C. pneumoniae DNA in peripheral blood mononuclear cells (PBMC) in patients with acute ischaemic heart disease. Samples of blood were obtained from 93 consecutive patients with acute ischaemic heart disease and from 42 healthy subjects, for detection of C. pneumoniae DNA in PBMC by polymerase chain reaction (PCR) and for serology. C. pneumoniae DNA in PBMC was detected in 25.8% (24/93) of the patients with acute ischaemic heart disease and in 4.8% (2/42) of the healthy subjects (P=0.008). C. pneumoniae IgG was found in 76.3% of patients and in 45.2% of healthy subjects (P=0.0008) while C. pneumoniae IgA was found in 59.1% and in 33.3%, respectively (P=0.01). No correlation was found between anti-C. pneumoniae antibody titers and positive PCR results. The detection of C. pneumoniae DNA in PBMC may aid in selecting patients who may benefit from antibiotic treatment; however, to support this contention, longitudinal studies on patients treated with antibiotics would also be necessary.

Midterm endothelial function and remodeling of radial artery grafts anastomosed to the aorta.

BACKGROUND: The purpose of this study was to elucidate the midterm endothelium-dependent vasodilatory capacity of radial artery grafts anastomosed to the aorta, as well as their morphometric evolution with the time. METHODS: Five years after surgery we evaluated the response of aorta-anastomosed radial artery grafts to the endovascular infusion of acetylcholine in 11 of the first 61 patients operated on at our institution, and we compared it to the response with that of internal thoracic artery grafts. Moreover, the first 20 patients who had a perfect radial artery graft on angiography at 1 year were restudied at 5 years and subjected to a comparative analysis of the diameters of the radial artery graft and the grafted coronary arteries. RESULTS: At midterm angiography, dilation of the 2 types of grafts was similar in response to acetylcholine administration (radial artery, from 2.61 +/- 0.39 to 2. 90 +/- 0.34 mm; internal thoracic artery, from 2.68 +/- 0.21 to 2.93 +/- 0.27 mm; P =.01 for both). The diameters of aorta-anastomosed radial artery grafts and grafted coronary arteries increased between both 1 and 5 years according to angiographic studies (radial artery grafts, from 2.08 +/- 0.45 to 2.54 +/- 0.53 mm; grafted coronary arteries, from 1.92 +/- 0.47 to 2.18 +/- 0.41 mm; P <.001 for both), but the increase was greater for the radial artery grafts (P <.001). CONCLUSIONS: Aorta-anastomosed radial artery grafts maintain an appreciable capacity for endothelium-dependent vasodilatation 5 years after implantation and undergo a progressive increase in luminal diameter with time. These observations contradict the presumed tendency for progressive fibrous intimal hyperplasia to develop in radial artery grafts.

Detection of Chlamydia pneumoniae in atherosclerotic coronary arteries.

Chlamydia pneumoniae has recently been associated with the development of coronary heart diseases by sero-epidemiological studies and by direct detection of the organism in atherosclerotic tissues. The aim of our study was to employ a semi-nested PCR approach to investigate the presence of C. pneumoniae in both normal and atherosclerotic coronary arteries of humans obtained at autopsy. Moreover, we have evaluated the role of infection with C. pneumoniae in relation to the extent of coronary atherosclerosis. One hundred and eighty coronary artery specimens were collected at autopsy from 60 consecutive subjects (three arterial segments from each subject). Atherosclerosis in each arterial segment was graded histologically by the Stary classification. Thirty normal coronary arteries were also taken at autopsy as control. PCR results evidenced the presence of C. pneumoniae DNA in atherosclerotic coronary arteries in 19 (31.7%) of 60 subjects examined, while none of the 30 subjects with non-atherosclerotic tissues was positive (p=0.001). Moreover, of the 180 atherosclerotic specimens examined, C. pneumoniae DNA was detected in 3.4% (2/59) of mild atherosclerotic lesions, and in 14.0% (17/121) of advanced atherosclerotic lesions (p=0.05). Our results demonstrate that the presence of C. pneumoniae DNA may be associated with the severity of coronary atherosclerosis.

Chlamydia pneumoniae infection in patients with acute coronary syndrome: a clinical and serological 1-year follow-up.

The role of Chlamydia pneumoniae infection in pathogenesis and prognostic stratification of patients with acute coronary syndromes is still unclear. However, a limitation of many studies is the evaluation of the long-term prognostic role of a sample obtained during the acute phase, whereas the assessment of the temporal trend of antibody titers could be more useful. One-hundred and fourteen consecutive patients with acute coronary syndromes (71 with acute myocardial infarction and 43 with unstable angina) were studied. Blood samples were obtained immediately after hospital admission and 1, 3, 6 and 12 months after the acute event. The microimmunofluorescence test was used to detect C. pneumoniae specific antibodies. The incidence of new coronary events (death, myocardial infarction, recurrent angina) was recorded during the 1-year follow-up period. No significant difference was found between patients with (n = 35) or without (n = 79) new coronary events (N.C.E.) regarding baseline and serial values of C. pneumoniae antibodies. The rate of high titers at any time of follow-up was also similar in the two groups: IgG > or =1:512 were present in 52%, 64%, 55% and 32% of N.C.E.+ patients, and in 48%, 54%, 52% and 36% of N.C.E.- patients at 1, 3, 6 and 12 months respectively; IgA > or =1:256 were present in 26%, 23%, 30% and 23% of N.C.E.+ patients and in 20%, 30%, 25% and 19% of N.C.E.- patients at 1, 3, 6 and 12 months respectively. Our data indicate that elevated titers of C. pneumoniae antibodies, even with a serial 1-year evaluation, are not a predictor of future coronary events in patients with acute myocardial infarction or unstable angina.

Reversible left anterior descending artery spasm, prolonged cardiac arrest and left main thrombosis during a PTCA attempt of the circumflex artery.

The authors report a case of percutaneous transluminal coronary angioplasty of the circumflex artery complicated by occlusion of the non-diseased left anterior descending artery by spasm. During advanced cardiac life support, required for the subsequent cardiac arrest, intra-coronary nitrates and calcium antagonists were administered. After 45 minutes, the spasm resolved, but N probably as a result of prolonged blood stasis N a thrombus appeared in the left main artery. While attempting to stent the left main, the thrombus was mechanically dislodged, leaving the epicardial coronary tree free, with a good flow.

Rhythm of carnitine levels in serum and urine of normal subjects.

A study of the diurnal serum and urine levels of L-carnitine and acetylcarnitine was carried out in eleven healthy volunteers. No significant difference was found between the levels in the morning and in the afternoon, although a higher carnitinaemia was shown in the waking hours when the energy demands were higher.