Chlamydia trachomatis elicits TLR3 expression but disrupts the inflammatory signaling down-modulating NFκB and IRF3 transcription factors in human Sertoli cells.

Chlamydia trachomatis, the leading cause of bacterial sexually transmitted diseases worldwide, can disseminate and localize to the upper genital tract impairing reproductive function. Specifically, ascending C. trachomatis genital infection has been demonstrated to cause epididymitis or epididymo-orchitis, well-known risk factors for male infertility. C. trachomatis possesses the ability to infect primary human Sertoli cells, key elements for the spermatogenetic process and the immune protection of germ cells. Therefore, herein, we investigated the innate immune response in Sertoli cells following C. trachomatis infection, as well as its indirect effects on human spermatozoa. Specifically, we evaluated C. trachomatis mediated induction of Toll-like Receptors (TLR) 2, 3 and 4 as well as of downstream intracellular signaling molecules (NFκB and IRF3) and the levels of the related inflammatory mediators (IL-1α, IL-6, IFN-α, IFN-ß and IFN-γ), in an in vitro infection model of primary human Sertoli cells. The main result of our study shows that C. trachomatis induced TLR3-mediated recognition in human Sertoli cells, accompanied by the down-modulation of NFκB and IRF3-dependent signaling pathways followed by no production of pro-inflammatory cytokines. In conclusion, our findings suggest that C. trachomatis can disrupt the innate immune response in Sertoli cells and evade intracellular killing, potentially giving rise to a long-term infection that may exert negative effects on the male reproductive system.

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.

New insights into Chlamydiae persistence: an energy metabolism strategy?

Chlamydiaceae is a family of obligate intracellular bacteria generally considered energy parasites. Several studies have suggested that Chlamydiae are capable of independently producing energy and, more importantly, several genes involved in the energy metabolism are up-regulated during the persistent state. Thus, it has been suggested that chlamydial persistence could be a complex and flexible metabolic strategy designed to favor a lengthy survival in the host cell by evading the immune response. In conclusion, more detailed studies on the shift in the chlamydial energy metabolism, from the active to the persistent form, may be helpful in future to determine whether chlamydial persistence observed in vitro does occur in vivo and whether chronic sequelae of chlamydial diseases may be related to the persistence.

Could past Chlamydial vascular infection promote the dissemination of Chlamydia pneumoniae to the brain?

Chlamydia pneumoniae, a pathogen responsible for respiratory tract infections, has been associated with atherosclerosis which, along with hypertension, hyperlipidemia, cardiovascular and/or cerebrovascular ischemia and stroke, is a risk factor for chronic neurological disorders. Several studies have demonstrated the ability of C. pneumoniae to disseminate from lungs to arteries through peripheral blood mononuclear cells. Once inside the vascular tissue, C. pneumoniae infection may disseminate via peripheral monocytes to the brain over the intact blood-brain barrier, and contribute to the development of chronic neurological disorders. The aim of our study was to evaluate whether past C. pneumoniae vascular infection may promote the dissemination of this microorganism to the brain, therefore we investigated the presence of C. pneumoniae in post-mortem brain tissue specimens of patients with past chlamydial vascular infection. Seventy six post-mortem brain tissue specimens from 19 patients with past chlamydial vascular infection were investigated for the presence of C. pneumoniae by immunohistochemistry, polymerase chain reaction, in situ polymerase chain reaction and in situ reverse transcription polymerase chain reaction. As control, 28 brain tissue specimens were taken from 7 age and sex matched subjects without chlamydial infection. C. pneumoniae was detected in 16 (84.2%) out of 19 patients with chlamydial vascular infection whereas it was not detected in control subjects (p= 0.0002). In conclusion, the main result of our study is the evidence that a chlamydial vascular infection can disseminate to the brain. It will be important for current and future researches to perform large-scale prospective studies on cardiovascular patients with chlamydial vascular infection in order to evaluate the long-term pathological alterations of the brain.

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.

The influence of plaque orientation (pericardial or myocardial) on coronary arterial remodeling.

BACKGROUND: Many systemic, regional and lesion factors have been identified which may influence arterial remodeling, but little is known about the importance of extravascular resistance to vessel enlargement. As myocardial systolic splinting may significantly affect vessel expansion the effect of plaque orientation on arterial remodeling in eccentric coronary atherosclerotic lesions was examined. METHODS: Using intravascular ultrasound imaging to obtain cross-sectional vessel area (VA), plaque area (PA) and lumen area (LA), remodeling in eccentric left anterior descending coronary artery lesions was compared which predominantly involved the pericardial or free arc (P, n=25) and the myocardial side (M, n=40) of the vessel wall. Normalized vessel area (NVA, VA(lesion)/VA(reference)) was compared as a continuous and categorical variable (positive>1.05, intermediate 0.95-1.05, negative<0.95) as well as remodeling index (RI, VA(lesion)-VA(reference)/PA(lesion)-PA(reference)). RESULTS: The two groups were well matched for clinical and lesion characteristics known to affect remodeling. Reference segments areas were similar in the two groups; while lesion LA was also similar, in the pericardial group there was significantly greater lesion PA (P 12.78+/-0.72, M 10.26+/-0.50 mm(2), P<0.05) and VA (P 15.71+/-0.90, M 12.82+/-0.57 mm(2), P<0.05) demonstrating enhanced compensatory remodeling. Outward remodeling was significantly greater in P than in M by both NVA (P 1.03+/-0.03, M 0.86+/-0.03, P<0.01) and RI (P 0.02+/-0.07, M -1.10+/-0.32, P<0.01). Positive, intermediate and negative remodeling occurred in nine, nine and seven lesions in P and in four, ten and 26 lesions in M (P<0.01). CONCLUSIONS: Remodeling compensates more for plaque growth in eccentric coronary lesions which are surrounded by the pericardium than those surrounded by the myocardium. Extravascular resistance appears to influence arterial remodeling.

Selective regional myocardial infiltration by the percutaneous coronary venous route: A novel technique for local drug delivery.

Recent advances in the treatment of heart disease, in particular cardiovascular gene therapy and therapeutic angiogenesis, highlight the need for efficient and practical local delivery methods for the heart. We assessed the feasibility of percutaneous selective coronary venous cannulation and injection as a novel approach to local myocardial drug delivery. In anesthetized swine, the coronary sinus was cannulated percutaneously and a balloon-tipped catheter advanced to the anterior interventricular vein (AIV) or middle cardiac vein (MCV). During balloon occlusion, venous injection of radiographic contrast caused regional infiltration of targeted myocardial regions. Complete AIV occlusion had no impact on LAD flow parameters. Videodensitometric analysis following venous injection showed that radiographic contrast persisted for at least 30 min. Selective regional myocardial infiltration is feasible by this approach, targeting selected myocardial beds, including the apex, anterior wall, septum, and inferoposterior wall. This novel technique has potential application for local myocardial drug or growth factor delivery. Cathet. Cardiovasc. Intervent. 51:358-363, 2000.

Photoangioplasty for human peripheral atherosclerosis: results of a phase I trial of photodynamic therapy with motexafin lutetium (Antrin).

BACKGROUND: In photoangioplasty, light activation of a photosensitive drug offers the potential for treatment of long segments of vascular disease. This is a brief description of a study designed to evaluate the safety and tolerability of a new photosensitizer, Antrin (motexafin lutetium), in the endovascular treatment of atherosclerosis. METHODS AND RESULTS: An open-label, single-dose, escalating drug- and light-dose study was performed in patients with atherosclerotic peripheral arterial insufficiency. Clinical evaluation, serial quantitative angiography, and intravascular ultrasonography were performed. Therapy was well tolerated, and only minor side effects were observed. Treatment produced no deleterious vascular effects. Although this study was not designed to examine clinical efficacy, several secondary end points suggested a favorable therapeutic effect. CONCLUSIONS: This phase I study demonstrates that photoangioplasty with motexafin lutetium is well tolerated and safe. Preliminary efficacy data suggest a future role for the treatment of flow-limiting atherosclerosis.

Adequacy of intracoronary versus intravenous adenosine-induced maximal coronary hyperemia for fractional flow reserve measurements.

BACKGROUND: Fractional flow reserve (FFR) is a measure of coronary stenosis severity that is based on pressure measurements obtained at maximal hyperemia. The most widely used pharmacologic stimulus for maximal coronary hyperemia is adenosine, administered either as a continuous intravenous (IV) infusion or intracoronary (IC) bolus. IV adenosine has more side effects and is more costly than IC adenosine but has a more stable and prolonged hyperemic effect. METHODS: We compared the efficacy of IC and IV adenosine administration for the measurement of FFR in a multicenter trial. Fifty-two patients with 60 lesions underwent determination of FFR with both IV and IC adenosine. IV adenosine was administered as a continuous infusion at a rate of 140 microgram/kg per minute until a steady state hyperemia was achieved. IC adenosine boluses were administered at a dose of 15 to 20 microgram in the right and 18 to 24 microgram in the left coronary artery. FFR was calculated as the ratio of the distal coronary pressure (from pressure guide wire) to the aortic pressure (guide catheter) at maximal hyperemia. RESULTS: A total of 26 left anterior descending, 23 right, 9 left circumflex, and 3 left main coronary arteries were evaluated. Mean percent stenosis for both groups was 55.8% +/- 23.6% (range 0% to 95%), and mean FFR was 0.78 +/- 0.15 (range 0.41 to 0.98). There was a strong and linear correlation between FFR measurements with IV and IC adenosine (R = 0.978, y = 0. 032 + 0.964x, P <.001). The agreement between the 2 sets of measurements was also high, with a mean difference in FFR of -0.004 +/- 0.03. However, a small random scatter in both directions of FFR measurements was noted with 5 lesions (8.3%) where FFR with IC adenosine was higher by 0.05 or more compared with IV infusions, suggesting a suboptimal hyperemic response in these patients. Changes in heart rate and blood pressure were significantly higher with IV adenosine. Two patients with IV, but none with IC adenosine, had severe side effects (bronchospasm and severe nausea). CONCLUSION: These results suggest that IC adenosine is equivalent to IV infusion for the determination of FFR in the majority of patients. However, in a small percentage of cases, coronary hyperemia was suboptimal with IC adenosine.

Effects of intravenous and intracoronary adenosine 5'-triphosphate as compared with adenosine on coronary flow and pressure dynamics.

BACKGROUND: Measurements of Doppler derived coronary flow reserve (CFR) and pressure derived fractional flow reserve (FFR) for coronary stenosis assessment depend on the induction of maximal hyperemia. Adenosine is the most widely used pharmacological agent but is expensive and poorly tolerated by some patients. METHODS AND RESULTS: The objective of this study was to test the equivalency of adenosine 5'-triphosphate (ATP) to adenosine in their ability to cause maximal hyperemia as compared with the hyperemic response of complete coronary occlusion in 6 canines. Intracoronary administration of either ATP or adenosine resulted in a significant increase in CFR (2.79+/-0.64 and 2.22+/-0.7 for 10 microgram versus 4. 65+/-1.22 and 4.25+/-0.78 for 100 microgram for ATP and adenosine, respectively, P for trend <0.001) but not reaching the level of coronary occlusion (6.35+/-2.26). Additionally, FFR and CFR were measured in 35 different stenoses using ATP, adenosine, and coronary occlusion. There was an excellent linear correlation between ATP and adenosine for both CFR (R=0.934, P<0.001) and FFR (R=0.985, P<0.001). However, hyperemia with either ATP or adenosine was less than postocclusion hyperemia, resulting in significantly different reserve measurements (CFR: 1.93+/-0.66 and 2.08+/-0.81 versus 2.35+/-0.97, P<0.001; FFR: 0.62+/-0.24 and 0.63+/-0.23 versus 0.58+/-0.2, P<0.001). CONCLUSIONS: 1) Step up in dosage of ATP and adenosine beyond currently recommended clinical doses resulted in a significant increase in coronary hyperemia; 2) ATP was equivalent to adenosine for both CFR and FFR; and 3) complete coronary occlusion yielded a better hyperemic response than either drug, indicating that maximal hyperemia was not achieved by either pharmacological stimulus.

Acute myocardial infarction and vascular remodeling.

We used intravascular ultrasound to show that outward remodeling predominates in lesions responsible for acute myocardial infarction, whereas negative remodeling is far more prevalent in lesions responsible for chronic stable angina. The total cholesterol:high-density lipoprotein ratio was also strongly correlated with outward remodeling.