Human cytomegalovirus and restenosis of the internal carotid artery

Persistent infection and vascular disease: a systematic review

More than 150 epidemiological or clinical studies have reported on associations between vascular disease and the presence of certain persistent bacterial and viral agents, or of clinical conditions (e.g., periodontal disease) that are associated with persistent infection. This article provides a review of such studies, particularly in relation to Helicobacter pylori, Chlamydia pneumoniae, dental disease and cytomegalovirus (CMV), as well as references to possible mechanisms. The association between coronary heart disease and H. pylori or between heart disease and dental disease may be accounted for by residual confounding. Although markers of C. pneumoniae infection are around twenty times more common in atherosclerotic plaques than in disease-free blood vessels, the sequence of infection and disease is uncertain. For CMV, a limited number of patients with classic atherosclerotic coronary heart disease have been investigated in seroepidemiological studies. For all such agents, better and larger seroepidemiological and pathology-based studies are needed to resolve these uncertainties, as well as - at some stage - large-scale, randomised intervention studies.

Upregulation of CD40 expression on endothelial cells infected with human cytomegalovirus

CD40 has been identified as an important molecule for a number of processes, such as immune responses, inflammation, and the activation of endothelia. We investigated CD40 in endothelial cells (EC) following infection with an endotheliotropic strain of human cytomegalovirus (HCMV). Between 8 and 72 h postinfection, we observed a significant increase in CD40 levels on the surface of infected EC, as measured by fluorescence-activated cell sorting analysis. As a consequence of CD40 upregulation, increased levels of E-selectin were found on infected EC after stimulation with CD154-expressing T cells. Enhanced expression of CD40 was specific for EC, since infection of fibroblasts did not result in the upregulation of CD40. The addition of neutralizing antibodies as well as UV inactivation of virus completely prevented the upregulation of CD40 on EC. Also, laboratory-adapted HCMV strain AD169 was not able to induce CD40 on EC. De novo protein synthesis was necessary for the increased surface expression. At early times (4 to 24 h) postinfection, this change was not accompanied by increased levels of CD40 protein or mRNA. At late times (48 to 96 h) postinfection, increased amounts of CD40 protein and mRNA were detected. Immunohistochemical analysis of infected tissues demonstrated elevated levels of CD40 on HCMV-infected EC in vivo. Thus, infection of EC by HCMV may result in the activation of endothelia and in the augmentation of inflammatory processes.

[Atherosclerosis, multiple sclerosis, and Alzheimer's disease: what role for Herpesviridae?]

Herpesviridae are ubiquitous, and are commonly involved in well identified diseases as genital herpes, chickenpox and herpes zoster, infectious mononucleosis, exanthem subitum... They are responsible for latent and chronic infections after primary infection. Atherosclerosis, multiple sclerosis, Alzheimer's disease are diseases which are very different, and for which pathogenesis remains unknown. Several authors have hypothesized that Herpesviridae could play a role in such diseases. The present paper reviews arguments not only in favour but also against such hypothesis. Any formal conclusion is impossible, and more extensive studies are warranted.

[Effect of cAMP on the function of endothelial cells and fibromuscular proliferation after the injury of the carotid and coronary arteries in a porcine model]

INTRODUCTION AND OBJECTIVE

Reendothelization of damaged blood vessels protects against the vascular injury response. We evaluated in vivo whether a systemic increase in cAMP accelerates reendothelization and attenuates intimal hyperplasia in injured swine carotid and coronary arteries.

METHODS

Both carotid arteries of 10 swines were subjected to balloon injury. Five animals had been treated with 2 ml (10 mg) of Forskolin, an activator of the adenylate cyclase, and another 5 with 2 ml of saline solution. These animals were sacrificed at day 8, and carotid artery reendothelization was evaluated. The descendent coronary (DC) artery of another 19 pigs was injured by atherotome. Nine animals had been treated with 2 ml of Forskolin, and another 10 with 2 ml of saline solution. These animals were sacrificed at day 28, with myointimal proliferation and arterial geometric remodelation being evaluated. Likewise, in these animals intracellular cAMP levels were measured at baseline and 28 and 60 minutes after saline solution or Forskolin administration and 90 min after arterial injury.

RESULTS

Eight days after balloon injury, carotid artery reendothelization was greater in the Forskolin-treated group compared with the control group (p = 0.02), and the number of CD31 positive cells was statistically increased in the treated group (38 +/- 11 cells) versus controls (11 +/- 9 cells). Although the degree of vascular injury caused by atherotome was similar in all of the arteries in the control group, restenosis was only observed in 40% of these animals. Correlation analysis demonstrated that intracellular cAMP may condition arterial geometric remodeling and the diameter of the lumen after vascular injury.

CONCLUSION

Our results suggest that cAMP may promote reendothelization and attenuate fibromuscular proliferation.

The possible role of infections in acute myocardial infarction

Cardiovascular diseases, particularly coronary heart disease (CHD) and myocardial infarction (MI), are among the leading causes for morbidity and mortality in industrialized countries [2, 77]. During the past decades, various clinical or lifestyle risk factors for myocardial infarction such as hyperlipidemia, hypertension, obesity, lack of physical exercise and smoking have been identified. However, it is also recognized that these well-documented risk factors do not sufficiently account for all new cases of myocardial infarction [77]. Many patients with myocardial infarction have only a borderline risk profile or even lack known risk factors. The question arises: What additional risk factors may play a role in the etiology of atherosclerosis and ischemic heart disease?

Giant cell (temporal) arteritis involving both external and internal carotid arteries

A 76-year-old woman with giant cell (temporal) arteritis was described; she presented with a one year history of headache and tinnitus. Histopathological findings from a superficial temporal artery showed arteritis with granulomatous changes. Bilateral carotid arteriograms demonstrated the stenoses of both internal carotid arteries as well as the narrowing of the superficial temporal arteries. Although we dermatologists rarely encounter the disease in daily clinical practice, it is of clinical importance to perform cerebral angiography in patients suspected of temporal arteritis.

Interferon gamma regulates acute and latent murine cytomegalovirus infection and chronic disease of the great vessels

To define immune mechanisms that regulate chronic and latent herpesvirus infection, we analyzed the role of interferon gamma (IFN-gamma) during murine cytomegalovirus (MCMV) infection. Lethality studies demonstrated a net protective role for IFN-gamma, independent of IFN-alpha/beta, during acute MCMV infection. Mice lacking the IFN-gamma receptor (IFN-gammaR-/-) developed and maintained striking chronic aortic inflammation. Arteritis was associated with inclusion bodies and MCMV antigen in the aortic media. To understand how lack of IFN-gamma responses could lead to chronic vascular disease, we evaluated the role of IFN-gamma in MCMV latency. MCMV-infected IFN-gammaR-/- mice shed preformed infectious MCMV in spleen, peritoneal exudate cells, and salivary gland for up to 6 mo after infection, whereas the majority of congenic control animals cleared chronic productive infection. However, the IFN-gammaR was not required for establishment of latency. Using an in vitro explant reactivation model, we showed that IFN-gamma reversibly inhibited MCMV reactivation from latency. This was at least partly explained by IFN-gamma- mediated blockade of growth of low levels of MCMV in tissue explants. These in vivo and in vitro data suggest that IFN-gamma regulation of reactivation from latency contributes to control of chronic vascular disease caused by MCMV. These studies are the first to demonstrate that a component of the immune system (IFN-gamma) is necessary to regulate MCMV-associated elastic arteritis and latency in vivo and reactivation of a herpesvirus from latency in vitro. This provides a new model for analysis of the interrelationships among herpesvirus latency, the immune system, and chronic disease of the great vessels.

Current aspects of diagnosis and treatment of cytomegalovirus infections in infants

BACKGROUND

Human cytomegalovirus (CMV) is the most common cause of congenital and perinatal infections throughout the world. High prevalence of CMV infection is associated mainly with universal breast feeding practices rather than with crowding or poverty. Perinatal CMV infection usually follows a benign course in immunocompetent individuals, but the virus remains latent or persistent in the host cell thereafter.

OBJECTIVE

As a clinical diagnosis of CMV infection is generally not easy, rapid and accurate laboratory diagnosis of CMV infection is required for appropriate patient management. Numerous anti-CMV compounds including ganciclovir, foscarnet and cidofovir have been reported, most of them are unlikely in a clinical trial for perinatal CMV infection in immunocompetent individuals. Understanding the epidemiology of CMV is a key element in the development of strategies for prevention and treatment of infection.

STUDY DESIGN

This review focuses on recent advances in the diagnosis and treatment of perinatal CMV infections in infants.

CONCLUSIONS

Entirely new approaches to prevention and treatment of CMV infections in infants are necessary, including antiviral interventions and the development of a vaccine strategy.

Chronic infections and coronary heart disease: is there a link?

A large number of studies have reported on associations of human coronary heart disease (CHD) and certain persistent bacterial and viral infections. We review the epidemiological and clinical evidence on CHD and Helicobacter pylori, Chlamydia pneumoniae, and cytomegalovirus (CMV), as well as possible mechanisms. The association between CHD and H pylori may be accounted for by residual confounding from risk factors. Although the association between C pneumoniae and CHD is stronger, the sequence of infection and disease is uncertain. As regards CMV, a limited number of patients with classic atherosclerotic coronary artery disease have been studied. Further studies are needed to resolve these uncertainties.