Resistin is not independently associated with CHD. Resistin is elevated in survivors of myocardial infarction; however, this reflects a novel association of raised resistin with diabetic nephropathy.

Objective-In a previous study we identified metallothionein (MT) as a candidate gene potentially influencing collaterogenesis. In this investigation, we determined the effect of MT on collaterogenesis and examined the mechanisms contributing to the effects we found. Methods and Results-Collateral blood flow recovery was assessed using laser Doppler perfusion imaging, and angiogenesis was measured using a Matrigel plug assay. Smooth muscle cells were isolated from MT knockout (KO) mice for functional assays. Gene expression of matrix metalloproteinase-9, platelet-derived growth factor, vascular endothelial growth factor, and Fat cadherin in smooth muscle cells was measured by real-time polymerase chain reaction, and protein levels of vascular endothelial growth factor and matrix metalloproteinase-9 were determined using enzyme-linked immunosorbent assay and Western blot. CD11b ϩ macrophages were tested for invasiveness using a real-time impedance assay. Both flow recovery and angiogenesis were impaired in MT KO mice. Proliferation, migration, and invasion were decreased in MT KO smooth muscle cells, and matrix metalloproteinase-9, plateletderived growth factor, and vascular endothelial growth factor expression were also decreased, whereas FAT-1 cadherin expression was elevated. MT KO CD11b ϩ cells were more invasive than wild-type cells. Conclusion-MT plays an important role in collateral flow recovery and angiogenesis, an activity that appears to be mediated, in part, by the effects of MT on the functionality of 3 cell types essential for these processes: endothelial cells, smooth muscle cells, and macrophages. Key Words: angiogenesis Ⅲ endothelial cell Ⅲ macrophage Ⅲ neovascularization Ⅲ smooth muscle cell I n a study in which we examined the temporal patterns of gene expression after acute hind limb ischemia in mice, we identified metallothionein (MT) as a candidate gene whose role in collaterogenesis and angiogenesis was worthy of further investigation. 1 MT are low-molecular-weight, cysteine-rich metal-binding proteins that play a role in the regulation of zinc and copper homeostasis, constituting a cellular defense against heavy metal toxicity and free radical activity. 2 MT is also a stress-response protein, induced by oxidative stressors and acute phase cytokines such as IL-1, 3 IL-6, and tumor necrosis factor-␣. 4 Mice overexpressing MT are protected from focal cerebral ischemia, 5-7 ischemia-reperfusion injury in the heart, 8,9 and apoptosis in cardiomyocytes. 10 -13 In MT knockout (KO) mice, impaired angiogenesis and wound healing have been reported in a model of cortical freeze injury. 14,15 In addition, there are numerous reports of MT having immunomodulatory effects. 16 -20 The objective of this study was to examine the role of MT in collateral vessel formation. To this end, both arteriogenesis and angiogenesis were assessed in MT KO mice. Additional experiments to explore possible mechanisms by which MT contributes to flow recovery were performed using aortic smooth muscle cells (SMC) and C...

Cerebrovascular disease (CVD) of both large and small cerebral vessels occurs in one-third of patients with sickle cell anemia (SCA) by age 20 years. Large vessel stenosis (LVS) occurs in ~10% of patients and is associated with overt stroke and/or (+) transcranial Doppler (TCD). Epistatic genetic modifiers are postulated to account for the significant phenotypic heterogeneity of SCA and likely contribute to CVD. Potential genetic modifers of CVD may be found in pathways for inflammation, adhesion, stress/immune reactions, angiogenesis, thrombosis, and oxidant generation. Peripheral blood monocytes are activated in SCA and contribute to inflammation and endothelial activation. The goal of this study is to determine if there is a difference in gene expression profiles of monocytes in patients with SCA and LVS, compared to SCA controls without CVD, and to normal African American (AA) controls. The study group consisted of 1) SCA patients with LVS [n = 6, (moyamoya = 3, no moyamoya =3)], 2) SCA patients without CVD and nornal TCD (n = 3), and 3) normal AA controls (n = 3). The 6 SCA-LVS patients were on chronic transfusion programs to maintain Hb S <30%. Monocytes were isolated by negative selection (RosetteSep Antibody) and total RNA extracted, converted to cRNA and hybridized to Affymetrix U133A GeneChip. Gene profiles were analyzed using dChip version 1.3 and gene lists were created for genes with a 2-fold or greater increase or decrease in expression with a Welch t-test p-values of 0.05 or less. Results: 1) SCA controls without CVD compared to AA controls revealed 50 differentially expressed genes (p<0.05), 16 with 2-fold or greater change. Differential gene expression was observed in pathways for angiogenesis (PD-ECGF, 5.1 fold, p = 0.025), cell signaling (lymphocyte antigen complex 6, 10.4 fold, p = 0.032, STAT1, 5.1 fold, p = 0.039), and inflammation (MARCO, 3.1 fold, p = 0.042). 2) SCA patients with LVS compared to SCA controls revealed 47 differentially expressed genes (p = <0.05) but only 6 genes with 2-fold or greater change. These included angiogenesis (PD-ECFG, -3.59 fold, p = 0.02), cell signaling (lymphocyte antigen complex 6, −4.61 fold, p = 0.02), adhesion (junction plakoglobin, −7.73 fold, p = 0.03), inflammation (LTA4H, 2.57 fold, p =0.009). These data suggest that patients with SCA and LVS overexpress leukotriene A4 hydrolase (LTA4H), an enzyme that catalyzes the final step in the leukotriene B4 (LTB4) pathway. LTB4 is a chemoattractant which triggers adhesion and aggregation of leukocytes to the endothelium. Five-lipoxygenase-activating protein (FLAP), a leukotriene pathway protein has recently been identified as a candidate gene for stroke and AMI risk in an Icelandic population. Also of interest, the SCA-LVS patients showed decreased expression of PD-ECFG and lymphocyte antigen complex 6, both genes being significantly overexpressed in SCA controls. Since the SCA-LVS patients are on chronic transfusion, underexpression could be due to the ameliorating effects of transfusion therapy. Validation studies of these findings are currently underway.

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