Separation analysis of lipoprotein classes have various methods, including ultracentrifugation, electrophoresis, and gel permeation chromatography (GPC). All major lipoprotein classes can be separated via ultracentrifugation, but performing the analysis takes a long time. Low-density lipoprotein (LDL), intermediate-density lipoprotein (IDL), and very low-density lipoprotein (VLDL) in patient samples cannot be sufficiently separated via electrophoresis or GPC. Thus, we established a new method [anion-exchange high-performance liquid chromatography (AEX-HPLC)] by using HPLC with an AEX column containing nonporous gel and an eluent containing chaotropic ions. AEX-HPLC can separate five lipoprotein fractions of high-density lipoprotein (HDL), LDL, IDL, VLDL, and others in human serum, which can be used in substitution for ultracentrifugation method. The method was also approved for clinical use in the public health-care insurance in Japan in 2014. Furthermore, we developed an additional method to measure cholesterol levels of the four leading lipoprotein fractions and two subsequent fractions (i.e., chylomicron and lipoprotein(a)). We evaluated the clinical usefulness of AEX-HPLC in patients with coronary heart disease (CHD), diabetes, and kidney disease and in healthy volunteers. Results indicate that the cholesterol levels in IDL and VLDL measured by AEX-HPLC may be useful risk markers of CHD or diabetes. Furthermore, we developed another new method for the determination of alpha-tocopherol (AT) in lipoprotein classes, and this method is composed of AEX-HPLC for the separation of lipoprotein classes and reverse-phase chromatography to separate AT in each lipoprotein class. The AT levels in LDL were significantly correlated with the lag time to copper ion-induced LDL oxidation, which is an index of oxidation resistance. The application of AEX-HPLC to measure various substances in lipoproteins will be clinically expected in the future.
Aim: It remains unclear whether elevated low-density lipoprotein cholesterol (LDL-C) is a risk factor for cerebral vascular disease. Familial hypercholesterolemia (FH) is the most appropriate model for understanding the effects of excess LDL-C because affected individuals have inherently high levels of circulating LDL-C. To clarify the effects of hypercholesterolemia on cerebral small vessel disease (SVD), we investigated cerebrovascular damage in detail due to elevated LDL-C using high resolution brain magnetic resonance imaging (MRI) in patients with FH.
Methods: Twenty-eight patients with FH and 35 healthy controls underwent 7T brain MRI. The prevalence of SVD and arterial structural changes were determined in each group.
Results: The prevalence of periventricular hyperintensity (PVH) was significantly higher (control, 0% vs. FH, 14.2%, p=0.021) and deep white matter intensity tended to be more frequent in FH patients than in controls. The prevalence of SVD in patients with forms of cerebral damage, such as lacunar infarction, PVH, deep white matter hyperintensities (DWMH), microbleeding, and brain atrophy, was significantly higher among FH patients (control, n=2, 5.7% vs. FH, n=7, 25.0%, p＜0.001, chi-square test). The tortuosity of major intracranial arteries and the signal intensity of lenticulostriate arteries were similar in the two groups. In FH patients, as the grade of PVH progressed, several atherosclerosis risk factors, such as body mass index, blood pressure, and triglyceride level, showed ever worsening values.
Conclusion: These results obtained from FH patients revealed that persistently elevated LDL-C leads to cerebral PVH. It is necessary in the management of FH to pay attention not only to the development of coronary heart disease but also to the presence of cerebral SVD.
Aims: The ankle-brachial index (ABI) can be a prognostic marker for chronic kidney disease (CKD) in Western populations. Since there is little relevant evidence for Asian populations, we investigated the relationship between ABI and the risk of incident CKD in a general Japanese population.
Methods: The cohort included 5,072 participants aged 30–79 without a history of renal disease or cerebro-cardiovascular disease. Incident CKD, defined as an estimated glomerular filtration rate ＜60 (mL/min/1.73 m2) and/or proteinuria (≥ 1＋ on urine dipstick), was compared among participants grouped according to baseline ABI: 0.90–0.99, 1.00–1.09, 1.10–1.19, 1.20–1.29, and 1.30–1.39. Hazard ratios for incident CKD were estimated using a Cox proportional hazards model, with the ABI 1.10–1.19 group serving as the reference.
Results: The CKD incidence rate (/100 person-years) was 1.80 during the mean follow-up period of 5.1 years. The CKD incidence rate was 3.04 in the ABI category 0.90–0.99, 1.58 in ABI 1.00–1.09, 1.72 in ABI 1.10–1.19, 2.01 in ABI 1.20–1.29, and 3.33 in ABI 1.30–1.39. The hazard ratios for developing CKD were 2.14 (95% confidence interval 1.16–3.92) in ABI 0.90–0.99, 1.08 (0.83–1.41) in ABI 1.00–1.09, 1.03 (0.83–1.29) in ABI 1.20–1.29, and 1.37 (0.77–2.47) in ABI 1.30–1.39, after adjusting for age, sex, systolic blood pressure, diabetes, and other confounding factors.
Conclusions: In a general Japanese population, an ABI of 0.90–0.99 was associated with an increased risk of incident CKD, independent of traditional cardiovascular risk factors.
Aim: Although coronary endothelial vasomotor dysfunction predicts future coronary events, there are few human studies showing the relationship between endothelial vasomotor dysfunction and atheroma plaque progression in the same coronary artery. This study examined whether endothelial vasomotor dysfunction is related to atheroma plaque progression in the infarct-related coronary artery of ST-segment elevation myocardial infarction (STEMI) survivors using serial assessment of coronary plaque size with intravascular ultrasound (IVUS) and coronary vasomotor responses to acetylcholine (ACh).
Methods: This study included 50 patients with a first acute STEMI due to occlusion of the left anterior descending coronary artery (LAD) and successful reperfusion therapy with percutaneous coronary intervention (PCI). IVUS and vasomotor response to ACh in the LAD were measured within two weeks of acute myocardial infarction (AMI) (1st test) and repeated six months (2nd test) after AMI under optimal anti-atherosclerotic therapies.
Results: Percent atheroma volume (PAV) and total atheroma volume (TAV) in the LAD progressed over six months of follow-up in 18 and 14 patients, respectively. PAV and TAV progression was significantly associated with persistent impairment of epicardial coronary artery dilation and coronary blood flow increase in response to ACh at both the 1st and 2nd tests. PAV and TAV progression had no significant association with traditional risk factors, PCI-related variables, medications, and the coronary vasomotor responses to sodium nitroprusside, an endothelium-independent vasodilator.
Conclusions: Persistent impairment of endothelial vasomotor function in the conduit arterial segment and the resistance arteriole was related to atheromatous plaque progression in the infarct-related coronary arteries of STEMI survivors.
Aim: Although metformin treatment has been reported to reduce the risk of cardiovascular events in patients with type 2 diabetes, the underlying mechanisms have not been elucidated fully. Here we assessed atherosclerotic lesion formation in newly established 2 mouse lines with different blood glucose levels (Oikawa-Nagao Diabetes-Prone [ON-DP] and -Resistant [ON-DR]) to evaluate the effect of metformin on early-stage atherosclerosis.
Methods: Mildly hyperglycemic ON-DP and normoglycemic ON-DR female mice fed an atherogenic diet for 20 weeks (8–28 weeks of age). During the feeding period, one group of each mouse line received metformin in drinking water (0.1%), while another group received water alone as control. Atherosclerotic lesion formation in the aortic sinus was quantitively analyzed from the oil red O-stained area of the serial sections.
Results: Metformin treatment did not affect food intake, body weight, and casual blood glucose levels within each mouse line during the 20-week feeding period. Nevertheless, metformin treatment significantly reduced atherosclerotic lesion formation in the ON-DP mice (59% of control), whereas no significant effect of metformin was observed in the lesion size of the ON-DR mice.
Conclusion: Metformin can attenuate early-stage atherogenesis in mildly hyperglycemic ON-DP mice. Pleiotropic effects of metformin, beyond its glucose-lowering action, may contribute to the antiatherogenic property in the early-stage atherosclerosis.
Aim: Serum alkaline phosphatase (ALP), a useful marker of hepatobiliary or bone disorders, has recently been found to be associated with cardiovascular diseases. This study aimed to examine the association of serum ALP level with arterial stiffness, as measured by brachial-ankle pulse wave velocity.
Methods: This cross-sectional study included 2476 participants (1486 men and 990 women) aged ≥ 20 years who underwent a medical examination. Pearson correlation analyses were conducted to examine the bivariate correlations between baPWV and clinical variables. To examine the independent relationship between serum ALP and baPWV, a multiple linear regression analysis was conducted with baPWV as the dependent variable in a sex-specific manner.
Results: After adjusting for age, body mass index, current smoking, alcohol drinking, regular exercise, hypertension, type 2 diabetes, dyslipidemia, chronic kidney disease, log-transformed AST, log-transformed ALT, and log-transformed GGT levels, log-transformed serum ALP level was positively and independently associated with baPWV (β=78.6 for men, P=0.001; and β=85.3 for women, P＜0.001).
Conclusions: Serum ALP level was positively and independently associated with baPWV in men and women, suggesting that an elevated ALP level may be a useful surrogate marker for arterial stiffness in adult men and women
Aim: To evaluate the association between cerebral arterial stiffness, measured using carotid–cerebral pulse wave velocity (ccPWV), and the initial severity estimated by the National Institutes of Health Stroke Scale (NIHSS) after acute ischemic stroke (AIS).
Methods: We prospectively studied 402 consecutive patients with first-ever acute cerebral infarction who underwent brain multimodal magnetic resonance, ccPWV, echocardiography, and carotid ultrasonography during the admission period. Their stroke subtypes were classified using the Trial of Org 10172 in Acute Stroke Treatment classification. Severe initial stroke severity was defined as an NIHSS score ＞6 on admission.
Results: We observed that 168 (41.79%) patients had severe initial stroke severity. A multivariate logistic regression analysis revealed that ccPWV [as a continuous variable; odds ratios (OR) (95% confidence intervals (CI)): 1.36 (1.08–1.72); P=0.010] and ccPWV ＞6.87 m/s [OR (95% CI): 8.13 (3.06–21.58); P＜0.001], calculated from the receiver-operating characteristic curve, remained independent determinants of severe initial stroke severity in three models. Furthermore, we observed that ccPWV significantly correlated with the NIHSS score, and the value of ccPWV was most strongly correlated with the NIHSS score (r=0.82, P＜0.001) in subjects with small vessel occlusion (SVO) among all stroke subtypes.
Conclusions: Cerebral arterial stiffness was independently associated with initial severity in AIS patients, and may be more strongly correlated with the initial SVO severity than those of other subtypes.
Aim: Computed tomography (CT) can directly provide information on body compositions and distributions, compared to anthropometric indices. It has been shown that various obesity indices are associated with carotid intima-media thickness (IMT). However, whether CT-based obesity indices are stronger than anthropometric indices in association with atherosclerosis remains to be determined in a general population.
Methods: We cross-sectionally assessed carotid IMT using ultrasound in 944 community-dwelling Japanese men free of stroke and myocardial infarction. CT image at the L4–L5 level was obtained to compute areas of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT). Anthropometric measures assessed included body mass index (BMI), waist circumference, and waist-to-hip ratio. Using multivariable linear regression, slopes of IMT per 20th to 80th percentile of each index were compared. We also compared the slope of index with simultaneous adjustment for BMI in the same model.
Results: Areas of VAT and SAT were positively associated with IMT, but not stronger than those of anthropometric indices in point estimates. Among all obesity indices, BMI was strongest in association with IMT after adjusting for age and lifestyle factors or further adjusting for metabolic factors. In simultaneous adjustment models, BMI, but not CT-based indices, remained significant and showed the strongest association.
Conclusions: In community-dwelling Japanese men, anthropometric obesity indices, BMI in particular, were more strongly associated with carotid atherosclerosis than CT-based obesity indices. The association of general obesity with carotid atherosclerosis was strong and adding CT-based obesity measure did not considerably influence in the association.