A high normal ankle-brachial index is associated with proteinuria in a screened cohort of Japanese: the Okinawa Peripheral Arterial Disease Study.

OBJECTIVES: We hypothesized that ankle-brachial index (ABI) increased with age as a result of arterial stiffness, and decreased when flow-limiting atherosclerotic stenosis occurred in the lower limbs. As arterial stiffness is associated with proteinuria, we investigated the relationship between ABI and prevalence of proteinuria. METHODS: A cross-sectional study of ABI and proteinuria with 13,193 participants aged 21-89 years (53% women) from health checkups between July 2003 and March 2010 was conducted. ABI was measured using the automatic oscillometric method, and stratified into four groups: ABI ≤ 0.9 (low); 0.9 < ABI <1.0 (borderline low); 1.0 ≤ ABI <1.2 (normal); and 1.2 ≤ ABI <1.4 (high normal). RESULTS: In participants with ABI at least 1.0, ABI was positively correlated with SBP, pulse pressure, and brachial-ankle pulse wave velocity. In participants with ABI less than 1.0, all indices were negatively correlated with ABI. The prevalence of proteinuria, defined as ≥ 1+ by dipstick, was significantly higher in low (23%) and high normal ABI (10%) compared with borderline low (6%) and normal ABI (7%). In participants at least 60 years, proteinuria was significantly associated with only low ABI [odds ratio (OR) 3.22, 95% confidence interval 1.34-7.41] compared with normal ABI before and after multivariable adjustment. In participants less than 60 years, adjusted OR for proteinuria was only significantly associated with high normal ABI (OR 1.32, 95% confidence interval 1.01-1.74). CONCLUSION: High normal ABI in younger participants may be a result of arterial stiffness and associated with proteinuria.

Age- and sex-related effects on ankle-brachial index in a screened cohort of Japanese: the Okinawa Peripheral Arterial Disease Study (OPADS).

AIMS: Age-related change of ankle-brachial index (ABI) within the general population, especially <40 years, has not been determined in large population studies. We evaluated the value of the ABI by age- and sex-related differences in a screened cohort. METHODS AND RESULTS: The ABI was examined in 13,211 participants (aged 21-89 years) in a health evaluation programme. The mean ABI was lower in women than in men at all ages. The ABI was lowest at <40 years, and increased with age; the maximum was at 60-69 years in both sexes. In participants <40 years, 186 (22%) of women and 108 (9.8%) of men had a borderline ABI (0.9-1.0). The prevalence of an ABI ≤0.9 in men increased with age, and sharply rose to 3.3% at ≥70 years. Conversely, women demonstrated a J-curve relationship, where the prevalence of an ABI ≤0.9 was lowest at 60-69 years (0.2%), and increased at <40 (0.9%) and ≥70 years (1.6%). The prevalence of atherosclerotic risk factors was higher in participants with an ABI ≤0.9 than those with an ABI >0.9 in men, both ≤60 and >60 years, and in women >60 years. In women ≤60 years, however, the prevalence of atherosclerotic risk factors in participants with an ABI >0.9 was as small as those with an ABI ≤0.9. CONCLUSION: The ABI increased with age until 60-69 years, and was lower in women than in men. It is unlikely that a low ABI in younger healthy women always indicate that existence of arterial stenosis.

Improvement of cardiac function after granulocyte-colony stimulating factor-mobilized peripheral blood mononuclear cell implantation in a patient with non-ischemic dilated cardiomyopathy associated with thromboangiitis obliterans.

Cardiac involvement is a rare complication with thromboangiitis obliterans (TAO). We report a 29-year-old man with TAO accompanied with non-ischemic dilated cardiomyopathy. He had no history of heart disease, but echocardiogram demonstrated diffuse hypokinesis and dilated left ventricle. Coronary angiography revealed no organic stenotic lesion. For limb salvage, he was treated with granulocyte-colony stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cell (PBMNC) implantation on his right leg. Not only ischemic leg symptoms, but also plasma level of BNP and (123)I-metaiodobenzylguanidine scintigraphic parameters improved after 24 weeks. G-CSF-mobilized PBMNC implantation could be an effective approach to treating non-ischemic cardiomyopathy.

Activator protein-1 mediates shear stress-induced prostaglandin d synthase gene expression in vascular endothelial cells.

OBJECTIVE: We attempted to determine the molecular mechanism of fluid shear stress-induced lipocalin-type prostaglandin D synthase (l-PGDS) expression in vascular endothelial cells. METHODS AND RESULTS: We examined the promoter region of the l-PGDS gene by loading laminar shear stress (20 dyne/cm2), using a parallel-plate flow chamber, on endothelial cells transfected with luciferase reporter vectors containing the 5'-flanking regions of the human l-PGDS gene. A deletion mutant analysis revealed that a shear stress-responsive element resided in the region between -2607 and -2523 bp. A mutation introduced into the putative binding site for activator protein-1 (AP-1) within this region eliminated the response to shear stress. In an electrophoretic mobility shift assay, shear stress stimulated nuclear protein binding to the AP-1 binding site, which was supershifted by antibodies to c-Fos and c-Jun. Shear stress elevated the c-Jun phosphorylation level in a time-dependent manner, similar to that of l-PGDS gene expression. SP600125, a c-Jun N-terminal kinase inhibitor, decreased the c-Jun phosphorylation, DNA binding of AP-1, and l-PGDS expression induced by shear stress. Additionally, an mRNA chase experiment using actinomycin D demonstrated that shear stress did not stabilize l-PGDS mRNA. CONCLUSIONS: Shear stress induces l-PGDS expression by transcriptional activation through the AP-1 binding site.

Physiology and pharmacology of the prostaglandin J2 family.

The prostaglandin (PG) J(2) family including PGJ(2), Delta(12)-PGJ(2), and 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)) are metabolites of PGD(2). They had been known as powerful inhibitors of cell proliferation and viral replication until 15d-PGJ(2) was found to be a natural ligand for peroxisome proliferator-activated receptor gamma (PPAR gamma). Since then, several new pharmacological actions of the PGJ(2) family have been found, such as pro- and anti-apoptotic effects, cell differentiation-inducing effects, and inhibitory effects on inflammatory processes, whether they depend on PPAR gamma or not. We reported that the PGJ(2) family, particularly 15d-PGJ(2), inhibits cell proliferation by reducing the expression of G(1) cyclins and inducing the expression of cyclin-dependent kinase inhibitor p21 and moreover, induces cell differentiation in vascular smooth muscle cells. In vascular endothelial cells, we found that 15d-PGJ(2) inhibits apoptotic cell death at least in part by the induction of the inhibitor of apoptosis protein c-IAP1. More importantly, physiological levels of laminar fluid shear stress loaded on endothelial cells upregulate the expression of lipocalin-type PGD(2) synthase, which converts PGH(2) to PGD(2), the precursor of the PGJ(2) family. Based on these results, we have hypothesized that the PGJ(2) family synthesized in vascular wall plays an important physiological role to protect vascular cells from atherogenic stimuli.

15-deoxy-delta 12,14-prostaglandin J2 and laminar fluid shear stress stabilize c-IAP1 in vascular endothelial cells.

Laminar shear stress strongly inhibits vascular endothelial cell apoptosis by unknown mechanisms. We reported that shear stress stimulates endothelial cells to produce 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) by elevating the expression level of lipocalin-type prostaglandin D synthase. To investigate the role of 15d-PGJ2 produced in the vascular wall, we examined the effect of 15d-PGJ2 on endothelial cell apoptosis. We induced apoptosis in human umbilical vein endothelial cells (HUVECs) by growth factor deprivation. 15d-PGJ2 strongly inhibited DNA ladder formation, nuclear fragmentation, and caspase-3-like activity in HUVECs. To elucidate the mechanism by which 15d-PGJ2 inhibits endothelial cell apoptosis, we examined expression of the inhibitor of apoptosis proteins (IAP) cellular-IAP1 (c-IAP1), c-IAP2, x-linked IAP, and survivin in HUVECs. In parallel with the inhibition of apoptosis, 15d-PGJ2 elevated the expression level of c-IAP1 protein in a dose- and time-dependent manner without changing the mRNA level. Laminar shear stress also induced c-IAP1 expression. Chase experiments with the use of cycloheximide revealed that 15d-PGJ2 and shear stress both inhibited the proteolytic degradation of c-IAP1 protein. These results suggested that 15d-PGJ2 inhibits endothelial cell apoptosis through, at least in part, c-IAP1 protein stabilization. This mechanism might be involved in the antiapoptotic effect of laminar shear stress.

Transcriptional and posttranscriptional regulation of cyclooxygenase-2 expression by fluid shear stress in vascular endothelial cells.

OBJECTIVE: Fluid shear stress induces cyclooxygenase (COX)-2 gene expression in vascular endothelial cells. We investigated the underlying mechanism of this induction. METHODS AND RESULTS: Exposure of human umbilical vein endothelial cells to laminar shear stress in the physiological range (1 to 30 dyne/cm2) upregulated the expression of COX-2 but not COX-1, a constitutive isozyme of COX. The expression of COX-2 mRNA began to increase within 0.5 hour after the loading of shear stress and reached a maximal level at 4 hours. Roles of the promoter region and the 3'-untranslated region in the human COX-2 gene were evaluated by the transient transfection of luciferase reporter vectors into bovine arterial endothelial cells. Shear stress elevated luciferase activity via the region between -327 and 59 bp. Mutation analysis indicated that cAMP-responsive element (-59/-53 bp) was mainly involved in this response. On the other hand, shear stress selectively stabilized COX-2 mRNA. Moreover, shear stress elevated luciferase activity when a 3'-untranslated region of COX-2 gene containing 17 copies of the AUUUA mRNA instability motif was inserted into the vector. CONCLUSIONS: Transcriptional activation and posttranscriptional mRNA stabilization contribute to the rapid and sustained expression of COX-2 in response to shear stress.

Shear stress induces expression of vascular endothelial growth factor receptor Flk-1/KDR through the CT-rich Sp1 binding site.

Fluid shear stress is 1 of the major factors that control gene expression in vascular endothelial cells. We investigated the role of shear stress in the regulation of the expression of fetal liver kinase-1/kinase domain region (Flk-1/KDR), a vascular endothelial growth factor receptor, by using human umbilical vein endothelial cells. Laminar shear stress (15 dyne/cm2) elevated Flk-1/KDR mRNA levels by approximately 3-fold for 8 hours, and the expression was upregulated within the range of 5 to 40 dyne/cm2. Deletion analysis of the 5'-flanking region of the Flk-1/KDR gene promoter by use of a luciferase reporter vector revealed that a shear stress-responsive element resided in the sequence between -94 and -31 bp, which contained putative nuclear factor-kappaB, activator protein-2, and GC-rich Sp1 and CT-rich Sp1 binding sites. Electrophoretic mobility shift assay demonstrated that nuclear extract was bound to the GC-rich Sp1 sites and the CT-rich Sp1 site with a similar pattern. However, shear stress enhanced the DNA-protein interactions only on the CT-rich Sp1 site but not on the GC-rich Sp1 sites. A 3-bp mutation in the CT-rich Sp1 site eliminated the response to shear stress in electrophoretic mobility shift assay and luciferase reporter assay. These results suggest that shear stress induces Flk-1/KDR expression through the CT-rich Sp1 binding site.