Abstract We evaluated the therapeutic efficacy of a novel drug eluting stent (DES) inhibiting inflammation and smooth muscle cell (SMC) proliferation. We identified CX3 CR1 as a targetable receptor ...for prevention of monocyte adhesion and inflammation and in-stent neointimal hyperplasia without interfering with stent re-endothelization. Efficacy of AZ12201182 (AZ1220), a CX3 CR1 antagonist was evaluated in inhibition of monocyte attachment in vitro . A prototype AZ1220 eluting PLGA-based polymer coated stent developed with an optimal elution profile and dose of 1 μM/stent was tested over 4 weeks in a porcine model of coronary artery stenting. Polymer coated stents without AZ1220 and bare metal stents were used as controls. AZ1220 inhibited monocyte attachment to CX3 CL1 in a dose dependent manner. AZ1220 eluted from polymer coated stents in an ex vivo flow system retained bioactivity in inhibiting monocyte attachment to CX3 CL1. At 4 weeks following deployment, AZ1220 eluting stents significantly reduced (∼60%) in-stent stenosis compared to both bare metal and polymer only coated stents and markedly reduced peri-stent inflammation and monocyte/macrophage accumulation without affecting re-endothelization. Anti-CX3 CR1 drug eluting stents potently inhibited in-stent stenosis and may offer an alternative to mTOR targeting by current DES, specifically inhibiting polymer-induced inflammatory response and SMC proliferation, while retaining an equivalent re-endothelization response to bare metal stents.
By its very nature, rupture of the atherosclerotic plaque is difficult to study directly in humans. A good animal model would help us not only to understand how rupture occurs but also to design and ...test treatments to prevent it from happening. However, several difficulties surround existing models of plaque rupture, including the need for radical interventions to produce the rupture, lack of direct evidence of rupture per se, and absence of convincing evidence of platelet- and fibrin-rich thrombus at the rupture site. At the present time, attention should therefore focus on the processes of plaque breakdown and thrombus formation in humans, whereas the use of animal models should probably be reserved for studying the function of particular genes and for investigating isolated features of plaques, such as the relationship between cap thickness and plaque stability.
The intranasal route was used to study Candida albicans infections in mice. Mice from two different inbred strains were challenged intranasally with C. albicans and the level of local and systemic ...colonization was monitored. DBA/2 mice were highly susceptible to challenge and viable C. albicans disseminated from the lungs to deeper tissues, including kidneys, liver and spleen within 48 h. In contrast, in BALB/c mice challenged in the same manner, C. albicans were retained within the lungs and cleared. Local and systemic anti-C. albicans immune responses were investigated. BALB/c mice exhibited higher titres of serum and mucosal anti-C. albicans IgA than DBA/2 mice. Splenocytes from BALB/c mice, but not from DBA/2 mice, produced detectable levels of interleukin-4 and -5 following stimulation with C. albicans antigens. Both DBA/2- and BALB/c-derived splenocytes produced interferon-gamma and interleukin-10 in response to similar stimulation. In conclusion, the intranasal route provided a simple, non-invasive murine model for investigating C. albicans infection through mucosal surfaces.
We have studied the genetics of susceptibility to infection by Streptococcus pneumoniae in mice. Linkage analysis of the F(2) generation from a cross between resistant BALB/cO1aHsd and susceptible ...CBA/CaO1aHsd strains allowed us to map a major locus controlling the development of bacteremia and survival after intranasal infection.
Abstract
Mice harbouring a null deletion mutation in the IFNγ receptor gene were used to study the role of IFNγ responsiveness during experimental systemic candidiasis of mucosal or haematogenous ...origin. After intravenous (i.v.) or intranasal (i.n.) challenge with Candida albicans the progression of infection and concomitant cellular and antibody anti-C. albicans immune responses were analysed. During the week following i.v. challenge, the rate of C. albicans multiplication in kidneys, liver and spleen was faster in IFNγR (−/−) than IFNγR (+/+) mice. As a result, IFNγR (−/−) mice perished earlier than IFNγR (+/+) mice when challenged with equal numbers of live yeast cells. However, the overall susceptibility of the two mouse strains, in terms of survival against different C. albicans challenge doses over a 60-day period, was similar. No differences were found in the cellular anti-C. albicans response generated by i.v. challenge in both mouse strains. In contrast the kinetics and strength of the serum anti-C. albicans antibody responses were markedly different. Significantly stronger, predominantly IgG2a antibody responses accompanied the eventual control of C. albicans infection in IFNγR (−/−) mice. Following intranasal challenge, there was no difference in the rate of C. albicans clearance from the lungs of IFNγR (−/−) and IFNγR (+/+) mice. However, 48 h after challenge, large, conspicuous abscesses appeared in the lungs, liver, kidneys and spleen of IFNγR (−/−) mice. These abscesses were characterised by the presence of C. albicans and abundant neutrophilic infiltrates, but very few macrophages. No such abscesses developed in i.n. challenged IFNγR (+/+) mice. In both mouse strains, i.n. challenge induced strong systemic anti-C. albicans cellular responses, but relatively low titre systemic antibody responses. Mucosal anti-C. albicans antibody responses were detected in IFNγR (+/+), but not IFNγR (−/−) mice. Splenic adherent macrophages obtained from IFNγR (−/−) mice exhibited a significantly lower candidacidal activity than those of IFNγR (+/+) mice, and as expected, were not responsive to IFNγ. In summary, these data suggest that IFNγ has a role in limiting C. albicans multiplication during the early stages of infection, as well as in preventing the development of C. albicans-associated abscesses. Activation of macrophages by IFNγ might be pivotal in mediating this role.
A repeated DNA sequence in the genome of Bordetella pertussis has been demonstrated. At least 20 copies of this sequence could be observed in either BamHI or EcoRI restriction enzyme digests of ...chromosomal DNA; fragments carrying the repeated DNA sequence ranged in size from about 1.5 to 20 kbp. The repeated DNA sequence was cloned from two separate regions of the B. pertussis genome, as shown by restriction enzyme site maps of the two clones and by hybridization studies. A small number of differences in the pattern of hybridization of the repeated DNA sequence to chromosomal DNA from several strains of B. pertussis was observed. No repeated DNA sequences were observed in one strain each of B. parapertussis and B. bronchiseptica, and there was no hybridization of B. pertussis DNA to Escherichia coli chromosomal DNA. The repeated DNA sequence was subcloned on a 2.54 kbp BamHI fragment from one of the two original clones. Restriction enzyme digests and hybridization studies showed that the repeated DNA sequence was about 1 kbp in size and had a single, internal ClaI site.
Two independent isolates of a Bordetella pertussis repeated DNA unit were sequenced and shown to be an insertion sequence element with five nucleotide differences between the two copies. The ...sequences were 1053 bp in length with near-perfect terminal inverted repeats of 28 bp, had three open reading frames, and were each flanked by short direct repeats. The two insertion sequences showed considerable homology to two other B. pertussis repeated DNA sequences reported recently: IS481 and a 530 bp repeated DNA unit. The B. pertussis insertion sequence would appear to comprise a group of closely related sequences differing mainly in flanking direct repeats and the terminal inverted repeats. The two isolates reported here, which were from the adenylate cyclase and agglutinogen 2 regions of the genome, were numbered IS48lvl and IS48lv2 respectively.
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