SPECT perfusion patterns distinguish psychogenic from essential tremor.

BACKGROUND: Psychogenic movement disorders pose formidable challenges to diagnosis and treatment reflecting our limited understanding of the basic brain mechanisms that cause them. Recently, functional brain imaging has been utilized to study psychogenic movement disorders. OBJECTIVES: To identify characteristic patterns of cerebral perfusion distinguishing psychogenic tremor (PT) from essential tremor (ET). METHODS: We studied five patients each with PT, ET and normal controls. SPECT imaging was performed at rest and during a tremor-inducing motor task. RESULTS: In ET, rest imaging revealed increased rCBF (relative cerebral blood flow) in cerebellar hemispheres and left inferior frontal gyrus. During the motor task, ET patients demonstrated increased rCBF in the supplementary motor area (SMA) and contralateral motor cortex and reduced rCBF in the cerebellum and visual cortex. In contrast, PT images at rest revealed increased rCBF in left inferior frontal gyrus and left insula. Motor task imaging revealed increased rCBF in the cerebellum and reduced rCBF in anterior regions of the default mode network. CONCLUSIONS: Our study revealed distinct patterns of cerebral perfusion during rest and motor task that distinguish PT from ET. Deactivation of the default mode network may serve as a marker for psychogenic movement disorders.

Local delivery of marrow-derived stromal cells augments collateral perfusion through paracrine mechanisms.

BACKGROUND: Bone marrow cell therapy is reported to contribute to collateral formation through cell incorporation into new or remodeling vessels. However, the possible role of a paracrine contribution to this effect is less well characterized. METHODS AND RESULTS: Murine marrow-derived stromal cells (MSCs) were purified by magnetic bead separation of cultured bone marrow. The release of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), placental growth factor (PlGF), and monocyte chemoattractant protein-1 (MCP-1) was demonstrated by analysis of MSC conditioned media (MSC-CM). MSC-CM enhanced proliferation of endothelial cells and smooth muscle cells in a dose-dependent manner; anti-VEGF and anti-FGF antibodies only partly attenuated these effects. Balb/C mice (n=10) underwent distal femoral artery ligation, followed by adductor muscle injection of 1x10(6) MSCs 24 hours later. Compared with controls injected with media (n=10) or mature endothelial cells (n=8), distal limb perfusion improved, and mid-thigh conductance vessels increased in number and total cross-sectional area. MSC injection improved limb function and appearance, reduced the incidence of auto-amputation, and attenuated muscle atrophy and fibrosis. After injection, labeled MSCs were seen dispersed between muscle fibers but were not seen incorporated into mature collaterals. Injection of MSCs increased adductor muscle levels of bFGF and VEGF protein compared with controls. Finally, colocalization of VEGF and transplanted MSCs within adductor tissue was demonstrated. CONCLUSIONS: MSCs secrete a wide array of arteriogenic cytokines. MSCs can contribute to collateral remodeling through paracrine mechanisms.

Marrow-derived stromal cells express genes encoding a broad spectrum of arteriogenic cytokines and promote in vitro and in vivo arteriogenesis through paracrine mechanisms.

We recently demonstrated that marrow stromal cells (MSCs) augment collateral remodeling through release of several cytokines such as VEGF and bFGF rather than via cell incorporation into new or remodeling vessels. The present study was designed to characterize the full spectrum of cytokine genes expressed by MSCs and to further examine the role of paracrine mechanisms that underpin their therapeutic potential. Normal human MSCs were cultured under normoxic or hypoxic conditions for 72 hours. The gene expression profile of the cells was determined using Affymetrix GeneChips representing 12 000 genes. A wide array of arteriogenic cytokine genes were expressed at baseline, and several were induced >1.5-fold by hypoxic stress. The gene array data were confirmed using ELISA assays and immunoblotting of the MSC conditioned media (MSC(CM)). MSC(CM) promoted in vitro proliferation and migration of endothelial cells in a dose-dependent manner; anti-VEGF and anti-FGF antibodies only partially attenuated these effects. Similarly, MSC(CM) promoted smooth muscle cell proliferation and migration in a dose-dependent manner. Using a murine hindlimb ischemia model, murine MSC(CM) enhanced collateral flow recovery and remodeling, improved limb function, reduced the incidence of autoamputation, and attenuated muscle atrophy compared with control media. These data indicate that paracrine signaling is an important mediator of bone marrow cell therapy in tissue ischemia, and that cell incorporation into vessels is not a prerequisite for their effects.

Effects of hepatitis A vaccination on atherogenesis in a murine model.

Our laboratory demonstrated that seropositivity to hepatitis A virus (HAV) independently predicts risk for coronary artery disease (CAD). As these findings are based only on the presence of HAV-specific antibodies, and not infectious virus, this prompted questions regarding possible effects of HAV vaccines on CAD development. If seropositivity to HAV alone, resulting from HAV vaccination, leads to increased atherogenesis, this raises important issues regarding the benefit of protection against HAV infection vs the risk of developing CAD. This study examines the effect of HAV vaccination on atherosclerosis development in a cholesterol-fed mouse model. Animals either received HAV vaccine, adjuvant, or saline. After 15 weeks, no significant differences were found in lesion area between the groups: HAV vaccine, 13,470 microm2; adjuvant, 16,332 microm2 and saline, 14,356 microm2. Only animals receiving HAV vaccination developed HAV-specific IgG. Thus, in this mouse model, vaccination against HAV does not contribute to the development of atherosclerosis.

Serum of cytomegalovirus-infected mice induces monocyte chemoattractant protein-1 expression by endothelial cells.

Inflammation plays a central role in atherogenesis. It was hypothesized that infection of apolipoprotein E-deficient mice with murine cytomegalovirus (MCMV) increases serum levels of proinflammatory cytokines, which may induce "proatherosclerotic" changes in endothelial cells (ECs). Serum samples were collected from uninfected and infected mice. ELISA was used to determine cytokine serum levels and monocyte chemoattractant protein-1 (MCP-1) levels in the supernatant of mouse ECs incubated with serum-containing medium. Serum samples from infected mice induced MCP-1 expression by ECs. These serum samples contain interferon (IFN)-gamma, whereas IFN-gamma was undetectable in serum samples from uninfected mice. Preincubating infected mouse serum with anti-IFN-gamma monoclonal antibody significantly decreased serum-induced EC expression of MCP-1. Thus, MCMV infection increases IFN-gamma serum levels, such serum can induce MCP-1 in ECs, and the serum-induced MCP-1 expression is due, at least in part, to IFN-gamma. If these changes in EC function also occur in vivo in response to infection, they could exacerbate atherogenesis.

Cytomegalovirus infection increases development of atherosclerosis in Apolipoprotein-E knockout mice.

Cytomegalovirus (CMV) infection has been associated with coronary artery disease, but it is unknown whether the virus can causally contribute to atherogenesis. To determine whether the virus has this capacity, we infected an atherosclerotic-prone mouse strain (C57BL/6J apoE-/-) with murine CMV. At 14 days of age, 30 mice received CMV (30000 pfu) ip and 30 received virus free media. At 13 and 16 weeks atherosclerotic lesion size was measured from aortic sinus cross-sections. Infection did not alter plasma levels of cholesterol, triglycerides, and high density lipoprotein (HDL); however, 4 weeks after infection IFNgamma levels were elevated (infection vs control: 156+/-49 vs 50+/-22 pg/ml, P=0.04). No differences in lesion size were present at 13 weeks post infection. However, by 16 weeks mean aortic sinus lesion area (mm(2)x10(3)+/-SEM; N=75) in the CMV-infected mice was significantly greater than in uninfected mice (74+/-6 vs 57+/-6; P=0.04). CMV caused the greatest increase (34%) in lesion size in females (103+/-9 vs 77+/-10; P=0.05; N=35). These results provide additional evidence implicating CMV as a causal agent of atherosclerosis, at least in an animal model.

Atherosclerosis in apoE knockout mice infected with multiple pathogens.

Cytomegalovirus (CMV) and Chlamydia pneumoniae (CP) possibly contribute to atherosclerosis. Murine CMV (MCMV) and CP increase lesion size in apoE knockout mice. In this study, apoE knockout mice were infected with MCMV and CP to determine whether infection with multiple pathogens increases lesion size to a greater extent than either pathogen alone and whether infection with MCMV changes serum cytokine levels in a manner that could increase lesion development. One group of mice received MCMV at 2 weeks of age, followed by 2 doses of CP at 6 and 8 weeks of age. Additional groups received only MCMV or CP. Animals were killed at 16 weeks of age to determine lesion area. Infection with MCMV alone, CP alone, and both MCMV and CP increased lesion size 84% (P<.001), 70% (P<.0001), and 45% (P<.01), respectively. The MCMV-induced increase in circulating levels of interferon-gamma may have contributed to this increase.

Potential live vaccines for HIV.

Potential live vaccines for HIV were developed using an Lpp-OmpA system to target an HIV antigen, reverse transcriptase, or an immunodominant epitope of this enzyme, to the outer membrane of an attenuated strain of Salmonella SL3261. These live vaccines were administered orally to mice, and fecal IgA and helper T cell responses were measured. Results indicated a fecal IgA response specific to HIV reverse transcriptase, as well as a reverse transcriptase-specific helper T cell response, as measured by proliferation assays. Additionally, tests with the epitope vaccines showed a selective cytotoxic CD8 T cell response. These results suggest that this method of antigen targeting to the outer membrane of attenuated bacterial vectors is very promising not only for HIV vaccine development, but also for antigens from other viral or bacterial pathogens, which could be inserted into the Lpp-OmpA protein construct, to elicit mucosal IgA and T cell responses.

Infection and atherosclerosis: potential roles of pathogen burden and molecular mimicry.

Infection has been implicated as a cause of atherosclerosis since the first half of the 19th century. Over the years, sporadic publications have appeared in the literature reflecting a persistent but relatively low level of research activity in this area. In the last decade, however, publications relating to this topic have increased markedly. And very recently, new epidemiological and mechanistic data relating infection to several different diseases, including atherosclerosis, have appeared, stimulating the emergence of important paradigm shifts in how we think about the causes of chronic disease. The following article reviews some of these newer concepts as they relate to a possible role of infection in atherosclerosis.