Human cytomegalovirus infection and atherothrombosis

Abstract

Vascular endothelium, as a key regulator of hemostasis, mediates vascular dilatation, prevents platelet adhesion, and inhibits thrombin generation. Endothelial dysfunction caused by acute or chronic inflammation, such as in atherosclerosis, creates a proinflammatory environment which supports leukocyte transmigration toward inflammatory sites, and at the same time promotes coagulation, thrombin generation, and fibrin deposition in an attempt to close the wound. Life-long persistent infection with human cytomegalovirus (HCMV) has been associated with atherosclerosis. In vivo studies have revealed that HCMV infection of the vessel wall affects various cells including monocytes/macrophages, smooth muscle cells (SMCs) and endothelial cells (ECs). HCMV-infected SMCs within vascular lesions display enhanced proliferation and impaired apoptosis, which contribute to intima-media thickening, plaque formation and restenosis. Monocytes play a central role in the process of viral dissemination, whereas ECs may represent a viral reservoir, maintaining persistent infection in HCMV-infected atherosclerotic patients following the primary infection. Persistent infection leads to dysfunction of ECs and activates proinflammatory signaling involving nuclear factor κB, specificity protein 1, and phosphatidylinositol 3-kinase, as well as expression of platelet-derived growth factor receptor. Activation of these pathways promotes enhanced proliferation and migration of monocytes and SMCs into the intima of the vascular wall as well as lipid accumulation and expansion of the atherosclerotic lesion. Moreover, HCMV infection induces enhanced expression of endothelial adhesion molecules and modifies the proteolytic balance in monocytes and macrophages. As a consequence, infected endothelium recruits naive monocytes from the blood stream, and the concomitant interaction between infected ECs and monocytes enables virus transfer to migrating monocytes. Endothelial damage promotes thrombin generation linking inflammation and coagulation. HCMV, in turn, enhances the thrombin generation. The virus carries on its surface the molecular machinery necessary to initiate thrombin generation, and in addition, may interact with the prothrombinase protein complex thereby facilitating thrombin generation. Thus, infection of endothelium may significantly increase the production of thrombin. This might not only contribute to thrombosis in patients with atherosclerosis, but might also induce thrombin-dependent proinflammatory cell activation. This review summarizes the existing evidence on the role of HCMV in vascular inflammation.

The Cell Biology of Cytomegalovirus: Implications for Transplantation

“…CMV infection causes EC activation with procoagulant effects, increasing the risk of vascular thrombosis (133,(135)(136)(137)(138)(139). In vitro, CMV infection of ECs induces platelet aggregation and adherence and expression of von Willebrand factor (vWF), ICAM1 and VCAM1.…”

Antagonistic Determinants Controlling Replicative and Latent States of Human Cytomegalovirus Infection

“…Further, congenital infection occurs in 1 in 150 children in the United States, making HCMV the leading cause of infectious disease-related birth defects (4)(5)(6)(7). The health cost of lifelong HCMV persistence is beginning to emerge as age-related pathologies associated with chronic inflammation, including atherosclerosis, immune senescence, and frailty (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). Understanding virus-host interactions important to HCMV persistence is essential to ultimately controlling the virus.…”

Complex Expression of the UL136 Gene of Human Cytomegalovirus Results in Multiple Protein Isoforms with Unique Roles in Replication

“…Further, infection in utero is the leading cause of infectious birth defects in the United States, affecting 1 in 150 infants born each year (4-7). The long-term health impacts of HCMV persistence are just beginning to be defined and include atherosclerosis, immune dysfunction, and frailty (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). The molecular mechanisms controlling persistence and latency remain obscure due to a lack of understanding of the viral and cellular related factors that contribute to multiple HCMV infection states, ranging from productive infection to latency.…”