Hidenori Koyama

Skin autofluorescence, a marker for advanced glycation end product accumulation, is associated with arterial stiffness in patients with end-stage renal disease

Elevated cardiovascular mortality has been shown to be associated with increased arterial stiffness. However, the contribution of tissue accumulation of advanced glycation end products (AGEs) to increased arterial stiffness is unclear. We examined whether skin autofluorescence, a recently developed marker of tissue accumulation of AGEs, is associated with arterial stiffness in 120 Japanese patients with end-stage renal disease (ESRD) and 110 age- and sex-matched control subjects. The ESRD patients had significantly higher pulse wave velocity (PWV), a noninvasive measure of arterial stiffness, and skin autofluorescence than the control subjects. Skin autofluorescence was significantly associated with age in the group of all subjects (R(s) = 0.255, Spearman rank correlation test) and that of control subjects (R(s) = 0.493), but not in the group of ESRD subjects (R(s) = 0.046). The PWV was significantly and positively associated with skin autofluorescence in the group of all subjects (R(s) = 0.335), controls (R(s) = 0.246), and ESRD subjects (R(s) = 0.205). Multiple regression analyses showed that, in the group of all subjects, association of skin autofluorescence with PWV was significant even after adjustment for other covariates including the presence of ESRD and age. Moreover, for ESRD subjects, a significant association between skin autofluorescence and PWV was found, independent of age. Our findings demonstrate the potential usefulness of skin autofluorescence in people of color and demonstrate clinically for the first time the potential involvement of tissue accumulation of AGEs in the pathophysiology of arterial stiffness.

Fatigue Is a Predictor for Cardiovascular Outcomes in Patients Undergoing Hemodialysis

BACKGROUND AND OBJECTIVESnDespite potential significance of fatigue and its underlying components in the occurrence of cardiovascular diseases, epidemiologic data showing the link are virtually limited. This study was designed to examine whether fatigue symptoms or fatigues underlying components are a predictor for cardiovascular diseases in high-risk subjects with ESRD.nnnDESIGN, SETTING, PARTICIPANTS, & MEASUREMENTSn788 volunteer patients under hemodialysis therapy (506 male, 282 female) completed the survey between October and November 2005, with the follow-up period up to 26 months to monitor occurrence of fatal or nonfatal cardiovascular events. The questionnaire consisted of 64 questions, and promax rotation analysis of the principal component method conceptualized eight fatigue-related factors: fatigue itself, anxiety and depression, loss of attention and memory, pain, overwork, autonomic imbalance, sleep problems, and infection.nnnRESULTSn14.7% of the patients showed fatigue scores higher than twice the SD of the mean for healthy volunteers. These highly fatigued patients exhibited a significantly higher risk for cardiovascular events (hazard ratio: 2.17; P < 0.01), with the relationship independent of the well-known risk factors, including age, diabetes, cardiovascular disease history, and inflammation and malnutrition markers. Moreover, comparisons of the risk in key subgroups showed that the risk of high fatigue score for cardiovascular events was more prominent in well-nourished patients, including lower age, absence of past cardiovascular diseases, higher serum albumin, and high non-HDL cholesterol.nnnCONCLUSIONSnFatigue can be an important predictor for cardiovascular events in patients with ESRD, with the relationship independent of the nutritional or inflammatory status.

Enhancement of Cell-Based Therapeutic Angiogenesis Using a Novel Type of Injectable Scaffolds of Hydroxyapatite-Polymer Nanocomposite Microspheres

Background Clinical trials demonstrate the effectiveness of cell-based therapeutic angiogenesis in patients with severe ischemic diseases; however, their success remains limited. Maintaining transplanted cells in place are expected to augment the cell-based therapeutic angiogenesis. We have reported that nano-hydroxyapatite (HAp) coating on medical devices shows marked cell adhesiveness. Using this nanotechnology, HAp-coated poly(l-lactic acid) (PLLA) microspheres, named nano-scaffold (NS), were generated as a non-biological, biodegradable and injectable cell scaffold. We investigate the effectiveness of NS on cell-based therapeutic angiogenesis. Methods and Results Bone marrow mononuclear cells (BMNC) and NS or control PLLA microspheres (LA) were intramuscularly co-implanted into mice ischemic hindlimbs. When BMNC derived from enhanced green fluorescent protein (EGFP)-transgenic mice were injected into ischemic muscle, the muscle GFP level in NS+BMNC group was approximate fivefold higher than that in BMNC or LA+BMNC groups seven days after operation. Kaplan-Meier analysis demonstrated that NS+BMNC markedly prevented hindlimb necrosis (P<0.05 vs. BMNC or LA+BMNC). NS+BMNC revealed much higher induction of angiogenesis in ischemic tissues and collateral blood flow confirmed by three-dimensional computed tomography angiography than those of BMNC or LA+BMNC groups. NS-enhanced therapeutic angiogenesis and arteriogenesis showed good correlations with increased intramuscular levels of vascular endothelial growth factor and fibroblast growth factor-2. NS co-implantation also prevented apoptotic cell death of transplanted cells, resulting in prolonged cell retention. Conclusion A novel and feasible injectable cell scaffold potentiates cell-based therapeutic angiogenesis, which could be extremely useful for the treatment of severe ischemic disorders.

Small dense low-density lipoprotein cholesterol concentration and carotid atherosclerosis

Low-density lipoprotein cholesterol (LDL-C) and the small dense LDL (SdLDL) phenotype are both predictors for ischemic heart disease. We examined whether cholesterol of SdLDL (SdLDL-C) is more closely associated with carotid artery intima-media thickness (CA-IMT), a surrogate measure of atherosclerosis, than LDL-C and other lipid parameters. The subjects were 326 consecutive participants including those with dyslipidemia, diabetes mellitus, hypertension, chronic kidney disease, and smokers. SdLDL-C was quantified by a newly developed precipitation method, and CA-IMT by high-resolution B-mode ultrasound. In univariate analysis, CA-IMT was most strongly correlated with SdLDL-C (Spearmans r=0.441, P<0.001), followed by apolipoprotein (apo) B, LDL-C, non-high-density lipoprotein cholesterol (Non-HDL-C), and plasma triglycerides (TG). HDL-C and apo A-I correlated inversely with CA-IMT. Non-lipid variables that were associated with CA-IMT were age, sex, presence of diabetes mellitus, presence of hypertension, estimate glomerular filtration rate (eGFR), and C-reactive protein (CRP). Even after adjustment for age, sex, diabetes mellitus, hypertension, smoking, eGFR and CRP, the positive association of CA-IMT with SdLDL-C remained significant, and again stronger than the associations with others lipid parameters. Further analyses revealed that the level of SdLDL-C was elevated in subgroups of the subjects including men, older subjects, smokers, those with higher CRP levels, those with diabetes mellitus, and hypertensive patients. These results indicate that SdLDL-C was the best marker of carotid atherosclerosis among the lipid parameters tested, and suggest that quantitative measurement of SdLDL-C gives useful information in the risk assessment for atherosclerotic disease.

Receptor for advanced glycation end-products (RAGE) regulation of adiposity and adiponectin is associated with atherogenesis in apoE-deficient mouse

OBJECTIVEnReceptor for advanced glycation end-products (RAGE) has been shown to be involved in cardiovascular diseases. We examined the involvement of RAGE in atherosclerosis under non-diabetic status, and its relation to the effect on adiposity.nnnMETHODSnApolipoprotein E (apoE)(-/-)RAGE(+/+) or apoE(-/-)RAGE(-/-) mice were fed with an atherogenic diet or the standard chow diet. Adiposity was determined by weight of epididymal adipose tissue, adipocyte size and serum adiponectin. Aortic atherosclerosis was morphometrically determined.nnnRESULTSnApoE(-/-)RAGE(-/-) mice exhibited significantly less total aortic plaque area than apoE(-/-)RAGE(+/+) mice. Body weight, epididymal fat weight, and epididymal adipocyte size were also significantly less in apoE(-/-)RAGE(-/-) mice than apoE(-/-)RAGE(+/+) mice. Serum adiponectin, but not tumor necrosis factor-alpha, was significantly higher in apoE(-/-)RAGE(-/-) mice than apoE(-/-)RAGE(+/+) mice. Simple regression analysis revealed that the total aortic plaque area was positively associated with epididymal fat weight, epididymal adipocyte size, and negatively with serum adiponectin levels. Multiple regression analyses revealed that RAGE genotype and serum adiponectin were mutually interrelated in determining aortic atherosclerosis. Finally, immunohistochemical and real-time RT-PCR analyses revealed that RAGE was indeed expressed in both adipocytes and endothelial cells in epididymal adipose tissue.nnnCONCLUSIONnRAGE-mediated regulation of adiposity in non-diabetic status could be attributable to the progression of atherosclerosis.

Advanced glycation end products, carotid atherosclerosis, and circulating endothelial progenitor cells in patients with end-stage renal disease.

Numbers of endothelial progenitor cells (EPCs) have been shown to be decreased in subjects with end-stage renal disease (ESRD), the mechanism of which remained poorly understood. In this study, mutual association among circulating EPC levels, carotid atherosclerosis, serum pentosidine, and skin autofluorescence, a recently established noninvasive measure of advanced glycation end products accumulation, was examined in 212 ESRD subjects undergoing hemodialysis. Numbers of circulating EPCs were measured as CD34+ CD133+ CD45(low) VEGFR2+ cells and progenitor cells as CD34+ CD133+ CD45(low) fraction by flow cytometry. Skin autofluorescence was assessed by the autofluorescence reader; and serum pentosidine, by enzyme-linked immunosorbent assay. Carotid atherosclerosis was determined as intimal-medial thickness (IMT) measured by ultrasound. Circulating EPCs were significantly and inversely correlated with skin autofluorescence in ESRD subjects (R = -0.216, P = .002), but not with serum pentosidine (R = -0.079, P = .25). Circulating EPCs tended to be inversely associated with IMT (R = -0.125, P = .069). Intimal-medial thickness was also tended to be correlated positively with skin autofluorescence (R = 0.133, P = .054) and significantly with serum pentosidine (R = 0.159, P = .019). Stepwise multiple regression analyses reveal that skin autofluorescence, but not serum pentosidine and IMT, was independently associated with low circulating EPCs. Of note, skin autofluorescence was also inversely and independently associated with circulating progenitor cells. Thus, tissue accumulated, but not circulating, advanced glycation end products may be a determinant of a decrease in circulating EPCs in ESRD subjects.

Biochemistry of uridine in plasma.

Uridine is a pyrimidine nucleoside that plays a crucial role in synthesis of RNA, glycogen, and biomembrane. In humans, uridine is present in plasma in considerably higher quantities than other purine and pyrimidine nucleosides, thus it may be utilized for endogenous pyrimidine synthesis. Uridine has a number of biological effects on a variety of organs with or without disease, such as the reproductive organs, central and peripheral nervous systems, and liver. In addition, it is used in clinical situations as a rescue agent to protect against the adverse effects of 5-fluorouracil. Since the biological actions of uridine may be related to its plasma concentration, it is important to examine factors that have effects on that concentration. Factors associated with an increase in plasma concentration of uridine include enhanced ATP consumption, enhanced uridine diphosphate (UDP)-glucose consumption via glycogenesis, inhibited uridine uptake by cells via the nucleoside transport pathway, increased intestinal absorption, and increased 5-phosphribosyl-1-pyrophosphate and urea synthesis. In contrast, factors that decrease the plasma concentration of uridine are associated with accelerated uridine uptake by cells via the nucleoside transport pathway and decreased pyrimidine synthesis.

Atheroprotective and plaque-stabilizing effects of enzymatically modified isoquercitrin in atherogenic apoE-deficient mice

OBJECTIVEnEnzymatically modified isoquercitrin (EMIQ), isoquercitrin with malto-oligosaccharides, has been recognized as generally recognized as safe by the Flavor and Extracts Manufacturers Association in the United States since 2003. The long-term antiatherogenic effect of EMIQ was examined using apolipoprotein E (apoE)-deficient atherogenic mice.nnnMETHODSnMale apoE-deficient mice (6 wk old) were fed with a high-fat diet alone or a diet containing EMIQ for 14 wk. At 20 wk old, atherosclerotic lesions in the aorta and aortic sinus were measured by morphometry and histomorphometry.nnnRESULTSnIn apoE-deficient mice, EMIQ did not significantly affect body weight, plasma total cholesterol, triacylglycerol, and high-density lipoprotein cholesterol throughout the experiment. EMIQ significantly suppressed the aortic atherosclerotic lesion area (control 8.8 +/- 3.5% versus EMIQ 4.4 +/- 1.5%, mean +/- SD, P = 0.022). Similarly, atherosclerotic plaque lesions in the aortic sinus were significantly reduced by EMIQ (control 37.7 +/- 3.6% versus EMIQ 30.2 +/- 2.0%, P = 0.010). Of note, the immunostained area for macrophage or 4-hydroxy-2-nonenal, a well-recognized marker of oxidative stress, at the plaque in the aortic sinus was markedly suppressed, whereas the area for collagen or smooth muscle cell were increased by EMIQ, suggesting a plaque-stabilizing effect of EMIQ.nnnCONCLUSIONnEMIQ has atheroprotective and plaque-stabilizing effects.

AGEs/RAGE in CKD: irreversible metabolic memory road toward CVD?

Eur J Clin Invest 2010; 40 (7): 623–635

Sleep, cardiac autonomic function, and carotid atherosclerosis in patients with cardiovascular risks: HSCAA study

OBJECTIVESnBehavioral and psychosocial factors have been gaining increased attention in regard to cardiovascular diseases. We evaluated sleep conditions, cardiac autonomic function, and carotid atherosclerosis in subjects who participated in the Hyogo Sleep Cardio-Autonomic Atherosclerosis (HSCAA) Study.nnnMETHODSnThis cross-sectional study included 330 serial patients registered in the HSCAA study who were free from past cardiovascular diseases, and prescribing α- or β-blockers. In addition to clinical background and classical cardiovascular risk factors, sleep efficiency, apnea hypopnea index (AHI), awake physical activity, heart rate variability (HRV), carotid intima-media thickness (IMT), presence of plaque and plaque score were determined.nnnRESULTSnSleep efficiency (rxa0=xa0-0.183) and all HRV parameters (SDNN: rxa0=xa0-0.202; rMSSD: rxa0=xa0-0.234; pNN50: rxa0=xa0-0.277) were significantly (pxa0<xa00.01) and negatively associated with IMT, while AHI (rxa0=xa00.220, pxa0<xa00.001) was positively associated with IMT. Similarly, sleep efficiency (rxa0=xa0-0.129), HRV parameters (SDNN: rxa0=xa0-0.170; rMSSD: rxa0=xa0-0.217; pNN50: rxa0=xa0-0.260) and AHI (rxa0=xa00.184) were also significantly (pxa0<xa00.05) associated with plaque scores. Multivariate logistic regression analyses showed that rMSSD, but not sleep efficiency or AHI, was significantly associated with carotid plaque (OR 0.74, 95% CI 0.56-0.98, pxa0=xa00.037), independent of classical risk factors. The association of rMSSD with carotid plaque remained significant even after adjustment for sleep efficiency or AHI. A comparison of risk factors in specific subgroups showed that the association of lower HRV with carotid plaque was more prominent in patients with cardiovascular risk factors including male gender, hypertension, dyslipidemia and diabetes mellitus.nnnCONCLUSIONnCardiac autonomic nervous dysfunction was independently associated with carotid atherosclerosis, independent of sleep condition. Moreover, that association was more prominent in specific subgroups with cardiovascular risk factors.