Adventitial delivery minimizes the proinflammatory effects of adenoviral vectors.
PURPOSE: Adenovirus-mediated arterial gene transfer is a promising tool in the study of vascular biology and the development of vascular gene therapy. However, intraluminal delivery of adenoviral vectors causes vascular inflammation and neointimal formation. Whether these complications could be avoided and gene transfer efficiency maintained by means of delivering adenoviral vectors via the adventitia was studied. METHODS: Replication-defective adenoviral vectors encoding a beta-galactosidase (beta-gal) gene (AdRSVnLacZ) or without a recombinant gene (AdNull) were infused into the lumen or the adventitia of rabbit carotid arteries. Two days after infusion of either AdRSVnLacZ (n = 8 adventitial, n = 8 luminal) or AdNull (n = 4 luminal), recombinant gene expression was quantitated by histochemistry (performed on tissue sections) and with a beta-gal activity assay (performed on vessel extracts). Inflammation caused by adenovirus infusion was assessed 14 days after infusion of either AdNull (n = 6) or vehicle (n = 6) into the carotid adventitia. Inflammation was assessed by means of examination of histologic sections for the presence of neointimal formation and infiltrating T cells and for the expression of markers of vascular cell activation (ICAM-1 and VCAM-1). To measure the systemic immune response to adventitial infusion of adenovirus, plasma samples (n = 3) were drawn 14 days after infusion of AdNull and assayed for neutralizing antibodies. RESULTS: Two days after luminal infusion of AdRSVnLacZ, approximately 30% of luminal endothelial cells expressed beta-gal. Similarly, 2 days after infusion of AdRSVnLacZ to the adventitia, approximately 30% of adventitial cells expressed beta-gal. beta-gal expression was present in the carotid adventitia, the internal jugular vein adventitia, and the vagus nerve perineurium. Elevated beta-gal activity (50- to 80-fold more than background; P <.05) was detected in extracts made from all AdRSVnLacZ-transduced arteries. The amount of recombinant protein expression per vessel did not differ significantly between vessels transduced via the adventitia (17.1 mU/mg total protein [range, 8.1 to 71.5]) and those transduced via a luminal approach (10.0 mU/mg total protein [range, 3.9 to 42.6]). Notably, adventitial delivery of AdNull did not cause neointimal formation. In addition, vascular inflammation in arteries transduced via the adventitia (ie, T-cell infiltrates and ICAM-1 expression) was confined to the adventitia, sparing both the intima and media. Antiadenoviral neutralizing antibodies were present in all rabbits after adventitial delivery of AdNull. CONCLUSION: Infusion of adenoviral vectors into the carotid artery adventitia achieves recombinant gene expression at a level equivalent to that achieved by means of intraluminal vector infusion. Because adventitial gene transfer can be performed by means of direct application during open surgical procedures, this technically simple procedure may be more clinically applicable than intraluminal delivery. Moreover, despite the generation of a systemic immune response, adventitial infusion had no detectable pathologic effects on the vascular intima or media. For these reasons, adventitial gene delivery may be a particularly useful experimental and clinical tool. (+info)
Expression of interleukin-10 in advanced human atherosclerotic plaques: relation to inducible nitric oxide synthase expression and cell death.
Inflammation is a major feature of human atherosclerosis and is central to development and progression of the disease. A variety of proinflammatory cytokines are expressed in the atherosclerotic plaque and may modulate extracellular matrix remodeling, cell proliferation, and cell death. Little is known, however, about the expression and potential role of anti-inflammatory cytokines in human atherosclerosis. Interleukin-10 (IL-10) is a major anti-inflammatory cytokine whose expression and potential effects in advanced human atherosclerotic plaques have not been evaluated. We studied 21 advanced human atherosclerotic plaques. IL-10 expression was analyzed by use of reverse transcription-polymerase chain reaction and immunohistochemical techniques. Inducible nitric oxide synthase expression was assessed by using immunohistochemistry, and cell death was determined by use of the TUNEL method. Reverse transcription-polymerase chain reaction identified IL-10 mRNA in 12 of 17 atherosclerotic plaques. Immunohistochemical staining of serial sections and double staining identified immunoreactive IL-10 mainly in macrophages, as well as in smooth muscle cells. Consistent with its anti-inflammatory properties, high levels of IL-10 expression were associated with significant decrease in inducible nitric oxide synthase expression (P<0.0001) and cell death (P<0. 0001). Hence, IL-10, a potent anti-inflammatory cytokine, is expressed in a substantial number of advanced human atherosclerotic plaques and might contribute to the modulation of the local inflammatory response and protect from excessive cell death in the plaque. (+info)
Cerebral arterial lesions resulting from inflammatory emboli.
In order to study the effects of septic embolism on the brain, silicone rubber emboli of various types were injected into the carotid arteries of 35 dogs. Pathologic and angiographic studies were performed to assess the resultant arterial and parenchymal lesions. Pure silicone rubber emboli (14 dogs) produced occasional intra-arterial thrombosis but no arteritis. Sterile and bacterially contaminated emboli containing a lead-chromate pigment (similar to those used in previous studies of septic embolism) (11 dogs) and pure silicone rubber emboli with transversely oriented canals (10 dogs), after brief placement in a bacterial suspension, were associated with intense inflammatory arteritis. This was accompanied by focal meningitis, subarachnoid hemorrhage, thrombosis, and cerebritis of the underlying cortex. The findings resembled those found in mycotic aneurysm. Aneurysmal dilatation was observed in one postmortem angiogram. In previous models of mycotic aneurysm, the inflammation attributed to bacterial contamination was probably due to the lead-chromate pigment used. (+info)
Systemic inflammatory parameters in patients with atherosclerosis of the coronary and peripheral arteries.
Plasma concentration of markers of inflammation are increased in patients with atherosclerosis. However, it is unclear whether the pattern and magnitude of this increase vary with the site and extent of disease. In 147 patients undergoing semiquantitative coronary angiography, we measured the acute-phase reactants C-reactive protein (CRP) or serum amyloid A (SAA); the proinflammatory cytokine interleukin 6 (IL-6); the active and total fractions of the anti-inflammatory cytokine transforming growth factor-beta (TGF-beta); the macrophage activation marker neopterin; and the infection marker procalcitonin. Compared with 62 patients without either coronary artery disease (CAD) or peripheral artery disease (PAD), 57 patients with CAD but no PAD showed greater median CRP (0. 4 versus 0.2 mg/dL, P=0.004) and IL-6 (3.8 versus 1.6 pg/mL, P=0. 007) levels and a lower level of active-TGF-beta (57 versus 100 ng/mL, P=0.038). Moreover, CRP, IL-6, and neopterin levels showed a positive and the active TGF-beta level a negative correlation with the extent of coronary atherosclerosis. Compared with these 57 patients with CAD alone, 15 patients with PAD and CAD had higher median levels of SAA (17 versus 7 mg/mL, P=0.008), IL-6 (12 versus 4 pg/mL, P=0.002), neopterin (14 versus 11 mg/dL, P=0.006), and total TGF-beta (11834 versus 6417 ng/L, P=0.001). However, these strong univariate associations of markers of inflammation and atherosclerosis were lost in multivariate analysis once age, sex, and high density lipoprotein cholesterol or fibrinogen were taken into account. Increased plasma levels of CRP, SAA, IL-6, TGF-beta, neopterin, and procalcitonin constitute an inflammatory signature of advanced atherosclerosis and are correlated with the extent of disease but do not provide discriminatory diagnostic power over and above established risk factors. (+info)
Clinical utility of the erythrocyte sedimentation rate.
The erythrocyte sedimentation rate (ESR) determination is a commonly performed laboratory test with a time-honored role. However, the usefulness of this test has decreased as new methods of evaluating disease have been developed. The test remains helpful in the specific diagnosis of a few conditions, including temporal arteritis, polymyalgia rheumatica and, possibly, rheumatoid arthritis. It is useful in monitoring these conditions and may predict relapse in patients with Hodgkin's disease. Use of the ESR as a screening test to identify patients who have serious disease is not supported by the literature. Some studies suggest that the test may be useful as a "sickness index" in the elderly or as a screening tool for a few specific infections in certain settings. An extreme elevation of the ESR is strongly associated with serious underlying disease, most often infection, collagen vascular disease or metastatic malignancy. When an increased rate is encountered with no obvious clinical explanation, the physician should repeat the test after an appropriate interval rather than pursue an exhaustive search for occult disease. (+info)
Unusual complications in an inflammatory abdominal aortic aneurysm.
An unusual case of an inflammatory abdominal aortic aneurysm (IAAA) associated with coronary aneurysms and pathological fracture of the adjacent lumbar vertebrae. The associated coronary lesions in cases of IAAA are usually occlusions. In the present case, it was concluded that a possible cause of the coronary aneurysm was coronary arteritis and the etiology of the pathological fracture of the lumbar vertebrae was occlusion of the lumbar penetrating arteries due to vasculitis resulting in aseptic necrosis. Inflammatory AAA can be associated with aneurysms in addition to occlusive disease in systemic arteries. The preoperative evaluation of systemic arterial lesions and the function of systemic organs is essential. (+info)
Arterial inflammation in mice lacking the interleukin 1 receptor antagonist gene.
Branch points and flexures in the high pressure arterial system have long been recognized as sites of unusually high turbulence and consequent stress in humans are foci for atherosclerotic lesions. We show that mice that are homozygous for a null mutation in the gene encoding an endogenous antiinflammatory cytokine, interleukin 1 receptor antagonist (IL-1ra), develop lethal arterial inflammation involving branch points and flexures of the aorta and its primary and secondary branches. We observe massive transmural infiltration of neutrophils, macrophages, and CD4(+) T cells. Animals appear to die from vessel wall collapse, stenosis, and organ infarction or from hemorrhage from ruptured aneurysms. Heterozygotes do not die from arteritis within a year of birth but do develop small lesions, which suggests that a reduced level of IL-1ra is insufficient to fully control inflammation in arteries. Our results demonstrate a surprisingly specific role for IL-1ra in the control of spontaneous inflammation in constitutively stressed artery walls, suggesting that expression of IL-1 is likely to have a significant role in signaling artery wall damage. (+info)
Neointima formation in a restenosis model is suppressed in midkine-deficient mice.
Neointima formation is a common feature of atherosclerosis and restenosis after balloon angioplasty. To find a new target to suppress neointima formation, we investigated the possible role of midkine (MK), a heparin-binding growth factor with neurotrophic and chemotactic activities, in neointima formation. MK expression increased during neointima formation caused by intraluminal balloon injury of the rat carotid artery. Neointima formation in a restenosis model was strongly suppressed in MK-deficient mice. Continuous administration of MK protein to MK-deficient mice restored neointima formation. Leukocyte recruitment to the vascular walls after injury was markedly decreased in MK-deficient mice. Soluble MK as well as that bound to the substratum induced migration of macrophages in vitro. These results indicate that MK plays a critical role in neointima formation at least in part owing to its ability to mediate leukocyte recruitment. (+info)