Oral Presentations - Arteriosclerosis, Thrombosis, and Vascular ...

y RNase protection analysis and an increase in IFN-gamma secreting CD4 T cell population
in splenocytes upon ex vivo challenge with MDA-LDL. This modulation of the immune response
in the ApoE-/-/PDGF-B-/- chimeras may contribute to their altered lesion formation. Supported
by NIH HL18645 and NIH 5T32HL07828.
P129
Angiographic Characteristics of Coronary Atherosclerosis in Patients with
Diabetes Mellitus
Stefan Aczel, Christoph Saely, Werner Benzer, Hannes Holzmueller, Wolfgang Fuchs, Peter
Langer, Heinz Drexel. VIVIT-Institute, LKH Feldkirch, Austria
Background:It is well established that coronary artery disease confers higher mortality in
diabetic than in non-diabetic subjects. The mechanisms causing this worse prognosis are
unclear. The notion that diabetic patients develop more diffuse and more peripheral
atherosclerosis could explain the poor outcome, but this pattern has been described rather in
type 1 than in type 2 diabetes. Methods: We performed a large-scale angiographic study
involving 757 consecutive patients referred to coronary. Extent of coronary atherosclerosis CA
was defined as the number of significant lesions (50 %), severity of CA as the mean
percentage of individual stenosis, and diffuse sclerosis as nonfocal, nonsignificant irregularity
of the coronary artery wall. According to the glycemic status patients were divided into 4
groups: established type 2 diabetes (n 128), fasting plasma glucose (FPG)125 mg/dl
(n60), HbA1c6.1 % and FPG126mg/dl (n99), and patients with none of the 3 criteria
(normoglycemic, n464). Results: Extent of CA was higher in the hyperglycemic than in the
normoglycemic patients (1.56 vs. 1.50 vs. 1.63 vs. 1.30). The 3 hyperglycemic groups did not
differ significantly by extent. Therefore they were pooled together and opposed to the
normoglycemic subjects. Extent of CA proved significantly increased in hyperglycemic subjects
(1.57 vs. 1.30, p 0.02). The severity of CA was comparable in all the groups (79.77 vs. 79.89
vs. 76.46 vs. 78.52% mean stenosis). The prevalence of diffuse coronary sclerosis also did not
differ significantly between the groups (70% vs. 75 % vs. 65 % vs. 66%). Conclusions: Thus
we can conclude that diabetic patients express a pattern of multifocal significant atherosclerotic
lesions whereas the severity of CA is not affected by the glycemic status. Moreover,
contrary to the current view, patients with type 2 diabetes do not have more diffuse coronary
disease than non-diabetic patients with CA. In summary, coronary atherosclerosis in diabetic
patients is specifically characterized by a significantly increased number of distinct focal
lesions. This pattern of CA is a ready explanation for increased mortality in diabetic patients.
P130
Hepatic Secretion but not the Synthesis of apo B-100 is Inhibited in apo
B-100-Only Mice Heterozygous for an apo B-38.9-Specifying Mutation
Zhouji Chen, Robin L Fitzgerald, Gustav Schonfeld. Washington University School of
Medicine, St Louis, MO
Apolipoprotein (apo) B-truncation-specifying mutations of the apo B gene (Apob) cause familial
hypobetalipoproteinemia (FHBL) in humans and Apob-modified mice. Kinetic studies on
heterozygous FHBL humans consistently show that production rates of apo B-100, the product
of the unaffected Apob allele, are reduced by 70%, instead of the expected 50%. To generate
a suitable mouse model to study the underlying mechanism, we crossbred our recently
reported apo B-38.9 mice with apo B-100-only (Apob 100/100 ) mice to produce mice doubly
heterozygous for apo B-100- and apo B-38.9-specifying alleles (Apob 100/38.9 ). The Apob 100/38.9
mice displayed typical FHBL phenotypes including a 75% reduction in plasma apo B-100 levels.
Two and 4 h after the simultaneous intravenous injection of 35 S-methionine/cysteine and Triton
WR-1339, the amounts of 35 S-labeled apo B-100 accumulated in plasma of Apob 100/38.9 mice
were only 25% and 10% of those of Apob 100/100 mice, respectively. Likewise, on continuous
metabolic labeling of cultured primary hepatocytes in the absence and presence of oleic acid
(OA) (0.5 mM), secretion rates of 35 S-labeled apo B-100 from the Apob 100/38.9 cells were 55%
and 70% lower than those of the Apob 100/100 cells, respectively. Apo B-100 synthetic rates in
the Apob 100/38.9 hepatocytes were reduced by 55% regardless of OA supplementation.
Pulse-chase studies showed that a larger proportion of newly synthesized apo B-100 was
subjected to intracellular degradation in Apob 100/38.9 than in Apob 100/100 hepatocytes. Furthermore,
while OA significantly inhibited intracellular apo B-100 degradation in Apob 100/100
hepatocytes, it was ineffective in Apob 100/38.9 hepatocytes. Together, these results provide
evidence for an inhibitory role for the apo B-truncation mutation in the secretion of apo B-100,
the product of the unaffected Apob allele, in an FHBL mouse model.
P131
An Ovary-Intact Mouse Model that Mimics Peri-Menopause in Women
Loretta P Mayer, Patrick J Devine, Patricia J Christian, Samuel L Marion, Gina M Buss,
Carole L Banka, Cheryl A Dyer, Patricia B Hoyer. University of Arizona, Tucson, AZ; Northern
Arizona University, Flagstaff, AZ; La Jolla Institute for Molecular Medicine, La Jolla, CA
Current menopause animal models rely on ovariectomized animals. However, this model does
not accurately represent the physiology of an ovary-intact menopausal woman. The menopausal
ovary is follicle-deplete and primarily composed of interstitial cells. Previous studies
have determined that repeated dosing of mice with the occupational chemical,
4-vinylcyclohexene diepoxide (VCD), selectively destroys primordial and primary ovarian
follicles by acceleration of the natural process of atresia resulting in pre-mature ovarian failure.
This study was designed to characterize an ovary-intact mouse with premature ovarian failure.
Female B6C3F1 mice (d28, n8/group) were dosed with VCD (160mg/kg, i.p.) for 15d (d43).
Ovaries were collected (d64) and prepared for histological evaluation. VCD treatment resulted
in ablation of primordial and primary follicles, and a reduction (p0.05) in secondary (6.6% of
control) and antral (37.7% of control) follicles. Compared with controls, circulating follicle
stimulating hormone (FSH), a clinical index of menopausal status, was increased (11.2ng/ml,
VCD; 1.7ng/ml, control, p0.05). VCD treatment did not alter body, adrenal, kidney or spleen
weights; however, ovarian and uterine weights were Downloaded smaller (p0.05). from
There was no evidence
Poster Presentations a-23
of liver damage as there was no elevation of plasma alanine aminotransferase (ALT) or
aspartate aminotransferase (AST), and histopathology of the liver in VCD-treated animals did
not differ from controls. Total plasma cholesterol was not altered in VCD-treated mice. Ovarian
interstitial cells express luteinizing hormone (LH) receptor as well as SR-BI, a scavenger
receptor that sequesters cholesterol for progestin and androgen production, and receptor
staining colocalized on interstitial cells, as visualized by immunoflourescence. Cultured cells
from ovaries of VCD-treated animals produced progesterone and androstenedione, which could
be stimulated by LH. These results demonstrate that the VCD-treated mouse reflects the
follicular content and hormonal status of the peri-menopausal woman. This model will likely be
useful for investigation of the development of cardiovascular disease in women as they age.
Angiotensin II Accelerated Atherosclerosis Is Attenuated in
Osteopontin-Deficient Mice
Dennis Bruemmer, Alan R Collins, Ulrich Kintscher, Grace Noh, Yuri Ozawa, Eckart Fleck,
Ronald E Law, Willa A Hsueh. UCLA, Los Angeles, CA; German Heart Institute, Berlin,
Germany
P132
Osteopontin (OPN) is a large acidic phosphoprotein containing the arginine-glycine-aspartate
(RGD) tripeptide integrin binding motif. OPN acts as an adhesion substrate and migration
stimulus by interaction with several integrins; these effects result in activation of cell signaling
pathways and regulation of gene expression. Overexpression of OPN has been identified in
atherosclerotic lesions in nondiabetic and diabetic animal models. Angiotensin II (AngII) is a
potent inducer of OPN expression in the vessel wall. We hypothesized that OPN may be a key
player in the early and late changes associated with development and progression of
AngII-accelerated atherosclerosis. To test this hypothesis we bred OPN-/- with ApoE-/- mice to
develop ApoE-/-OPN/- heterozygote mice deficient in OPN. Three month old male ApoE-/-
OPN/- heterozygote mice and ApoE-/-OPN/ littermate controls were infused with 2.5
microg/kg/min AngII for four weeks. Both groups of mice developed marked hypertension
(systolic 160 mmHG vs. 102 mmHG in control animals). En face analysis of the thoracic aorta
revealed a significant decrease in atherosclerotic lesions in OPN/- heterozygotes compared
to OPN/ animals (5.5 0.8 n7 vs. 15.3 1.3 n4, p0.01). Real time PCR analysis
confirmed that OPN mRNA expression in aortae of OPN/- mice was decreased by
approximately 50% compared to littermate controls. Lipid profiles were similar between
OPN/ and OPN/- mice. Peritoneal macrophages from OPN/- mice exhibited an
impaired chemotactic response towards MCP-1 in transwell migration assays which could
contribute to the diminished atherosclerosis observed in these animals after AngII-infusion.
These data suggest that OPN is an important proatherogenic factor in the vessel wall.
Approaches designed to inhibit OPN expression and/or adhesion in the vasculature may provide
a novel therapeutic strategy against atherosclerosis.
P133 WITHDRAWN
P134
Progress with the Calibration of a 3F Near Infrared Spectroscopy Fiber
Optic Catheter for Monitoring the pH of Atherosclerotic Plaque: Introducing
a Novel Approach for Detection of Vulnerable Plaque
Tania Khan, Babs Soller, Mohammad Madjid, James T Willerson, Samuel W Casscells III,
Morteza Naghavi. University of Massachusetts, Worcester, MA; Division of Cardiology,
University of Texas-Houston Health Science Center, and Texas Heart Institute, Houston, TX
Near-infrared (NIR) spectroscopy has been proposed to characterize structural properties of
vulnerable plaques (VP). We hypothesized that localization of VP can be enhanced by
physiological factors such as low pH, high temperature (T), NO, hypoxia, and oxyradicals, which
shift NIR spectra. Previously, we have shown that inflamed regions of plaque have lower pH.
Therefore, we chose pH to calibrate our spectroscopy catheter. Methods: Different probe sizes
were used. Eventually, using a unique miniaturized fiber optic side-viewing catheter, we
demonstrated the feasibility of performing the correlation. 5 human carotid endarterectomized
plaques were collected and placed immediately in a humidified, 37 C controlled T glove-box
type incubator. Optical reflectance spectra (ORS)(400 –1100 nm) were taken with the prototype
catheter connected to a spectrometer. 17 tissue pH readings were done (using microelectrodes)
and correlated with matching ORS. Partial Least Squares multivariate calibration
techniques were used. Results: Probe miniaturization localized the optical spectra and allowed
previously undetected quantitative differences to be detected in the heterogeneous plaque. The
range of the electrode pH was 6.83 to 7.54. The R2 of the determination of tissue pH from the
optical NIR calibration was 0.63 and the Root Mean Squared Deviation (RMSD) was 0.14 pH
units. Conclusion: This feasibility study suggests that plaque pH can be determined with NIR
spectroscopy both ex vivo and in vivo. Further improvements in signal-to-noise ratio is required
to meet the goal of detection of VP by pH.
http://atvb.ahajournals.org/ by guest on April 4, 2013