Chronic vascular diseases such as atherosclerosis, aneurysms, diabetic angiopathy/retinopathy as well as fibrotic and proliferative vascular diseases are generally complicated by the progression of degenerative insults, which are characterized by endothelial dysfunction, apoptotic/necrotic cell death in vascular/immune cells, remodeling of extracellular matrix or breakdown of elastic lamella. Increasing evidence suggests that dysfunctional calpain proteolytic systems and defective calpain protein metabolism in blood vessels contribute to degenerative disorders. In vascular endothelial cells, the overactivation of conventional calpains consisting of calpain-1 and -2 isozymes can lead to the disorganization of cell-cell junctions, dysfunction of nitric oxide synthase, sensitization of Janus kinase/signal transducer and activator of transcription cascades and depletion of prostaglandin I₂, which contributes to degenerative disorders. In addition to endothelial cell dysfunctions, calpain overactivation results in inflammatory insults in macrophages and excessive fibrogenic/proliferative signaling in vascular smooth muscle cells. Moreover, calpain-6, a non-proteolytic unconventional calpain, is involved in the conversion of macrophages to a pro-atherogenic phenotype, leading to the pinocytotic deposition of low-density lipoprotein cholesterol in the cells. Here, we discuss the recent progress that has been made in our understanding of how calpain contributes to degenerative vascular disorders.

Sphingosine 1-phosphate (S1P) is a potent lipid mediator that works on five kinds of S1P receptors located on the cell membrane. In the circulation, S1P is distributed to HDL, followed by albumin. Since S1P and HDL share several bioactivities, S1P is believed to be responsible for the pleiotropic effects of HDL. Plasma S1P levels are reportedly lower in subjects with coronary artery disease, suggesting that S1P might be deeply involved in the pathogenesis of atherosclerosis. In basic experiments, however, S1P appears to possess both pro-atherosclerotic and anti-atherosclerotic properties; for example, S1P possesses anti-apoptosis, anti-inflammation, and vaso-relaxation properties and maintains the barrier function of endothelial cells, while S1P also promotes the egress and activation of lymphocytes and exhibits pro-thrombotic properties. Recently, the mechanism for the biased distribution of S1P on HDL has been elucidated; apolipoprotein M (apoM) carries S1P on HDL. ApoM is also a modulator of S1P, and the metabolism of apoM-containing lipoproteins largely affects the plasma S1P level. Moreover, apoM modulates the biological properties of S1P. S1P bound to albumin exerts both beneficial and harmful effects in the pathogenesis of atherosclerosis, while S1P bound to apoM strengthens anti-atherosclerotic properties and might weaken the pro-atherosclerotic properties of S1P. Although the detailed mechanisms remain to be elucidated, apoM and S1P might be novel targets for the alleviation of atherosclerotic diseases in the future.

Diabetic macroangiopathy, atherosclerosis secondary to diabetes mellitus (DM), causes cerebro-cardiovascular diseases, which are major causes of death in patients with DM and significantly reduce their quality of life. The alterations in vascular homeostasis due to endothelial and vascular smooth muscle cell dysfunction are the main features of diabetic macroangiopathy. Although multiple metabolic abnormalities that characterize diabetes are involved in the progression of atherosclerosis in patients with DM, it may be said that prolonged exposure to hyperglycemia and insulin resistance clustering with other risk factors such as obesity, arterial hypertension, and dyslipidemia play crucial roles. Laboratory and clinical researches in the past decades have revealed that major biochemical pathways involved in the development of diabetic macroangiopathy are as follows: overproduction of reactive oxygen species, increased formation of advanced glycation end-products (AGEs) and activation of the AGEs-receptor for AGE axis, polyol and hexosamine flux, protein kinase C activation, and chronic vascular inflammation. Among them, oxidative stress is considered to be a key factor.

Aims: Recent studies suggested that subclasses of high-density lipoprotein (HDL) may be a better biomarker to predict the risk of atherosclerotic disorders. We aimed to examine the association of HDL2- and HDL3-cholesterol (HDL2-C and HDL3-C) with carotid intima-media thickness (IMT) using a new method to quantify the HDL-C subclasses.

Methods: Participants were 657 Japanese subjects (434 women) who received a health examination (mean age: 73 years). Serum samples were analyzed by the homogenous assay for HDL-C and HDL3-C. HDL2-C was calculated indirectly by subtracting HDL3-C from HDL-C. HDL3-C measured by this assay was well correlated with that measured by ultracentrifugation (r=0.898, p＜0.001). The maximum IMT (max-IMT) and plaque score (PS) were evaluated by ultrasonography following the standard protocol.

Results: HDL3-C was associated with age both in men (r=－0.322, p＜0.0001) and women (r=－0.315, p＜0.0001). In a simple regression analysis, max-IMT showed an inverse association with HDL3-C, whereas no significant association was observed with HDL2-C. A multiple linear regression analysis indicated, however, that the association between HDL3-C and max-IMT was not significant in both aged and younger populations when age was included in the analysis. Further, not only HDL2-C but also HDL3-C was not a significant predictor of ‘atherosclerotic arteries' defined as the max-IMT ≥1.5 mm. Similar results were observed in the analysis on PS.

Conclusions: Neither HDL3-C nor HDL2-C was significantly associated with carotid atherosclerosis in the Japanese population in this study.

Aim: Accumulating evidence suggests that predictability of traditional cardiovascular risk factors declines with advancing age. We investigated whether carotid plaque scores (CPSs) were associated with cardiovascular disease (CVD) death in the oldest old, and whether asymmetrical dimethylarginine (ADMA), a marker of endothelial dysfunction, moderated the association between the CPS and CVD death.

Methods: We conducted a prospective cohort study of Japanese subjects aged ≥85 years without CVD at baseline. We followed this cohort for 6 years to investigate the association of CPS with CVD death via multivariable Cox proportional hazard analysis. We divided participants into three groups according to CPS (no, 0 points; low, 1.2–4.9 points; high, ≥5.0 points). The predictive value of CPS for estimating CVD death risk over CVD risk factors, including ADMA, was examined using C-statistics.

Results: We analyzed 347 participants (151 men, 196 women; mean age, 87.6 years), of which 135 (38.9%) had no carotid plaque at baseline, and 48 (13.8%) had high CPS. Of the total, 29 (8.4%) participants experienced CVD-related death during the study period. Multivariable analysis revealed a significant association of high CPS with CVD-related mortality relative to no CPS (hazard ratio, 3.90; 95% confidence interval: 1.47–10.39). ADMA was not associated with CVD death, but the significant association between CPS and CVD death was observed only in lower ADMA level. The addition of CPS to other risk factors improved the predictability of CVD death (p=0.032).

Conclusions: High CPS correlated significantly with a higher CVD death risk in the oldest old with low cardiovascular risk. Ultrasound carotid plaque evaluation might facilitate risk evaluations of CVD death in the very old.

Aim: Statins have a protective impact against cardiovascular diseases through not only lipid-lowering effects but also pleiotropic effects, including activation of the endothelial nitric oxide synthase (eNOS) system. We aimed to clarify the protective effects of a statin against atherogenesis and ischemia in eNOS^－/－ mice.

Methods: Study 1. eNOS^－/－ Apolipoprotein E (ApoE)^－/－ mice were treated with a vehicle or pitavastatin (0.3 mg/kg/day) for 4 weeks. Study 2. eNOS^－/－ mice were also treated with a vehicle or the same dose of pitavastatin for 2 weeks prior to hind-limb ischemia.

Results: In Study 1, pitavastatin attenuated plaque formation and medial fibrosis of the aortic root with decreased macrophage infiltration in eNOS^－/－ ApoE^－/－ mice. PCR array analysis showed reductions in aortic gene expression of proatherogenic factors, including Ccl2 and Ccr2 in pitavastatin-treated double mutant mice. In addition, pitavastatin activated not only atherogenic p38MAPK and JNK but also anti-atherogenic ERK1/2 and ERK5 in the aorta of the double mutant mice. In Study 2, pitavastatin prolonged hind-limb survival after the surgery with increased BCL2-to-BAX protein ratio and inactivated JNK. Enhanced expression of anti-apoptotic genes, including Vegf, Api5, Atf5, Prdx2, and Dad1, was observed in the ischemic limb of pitavastatin-treated eNOS^－/－ mice. Furthermore, pitavastatin activated both aortic and skeletal muscle AMPK in the eNOS-deficient vascular injury models.

Conclusion: Pitavastatin exerts eNOS-independent protective effects against atherogenesis and hind-limb ischemia in mice, which may occur via modifications on key molecules such as AMPK and diverse molecules.

Aims: Excessive consumption of sugar-sweetened beverages (SSBs) may increase the prevalence of obesity and other metabolic risk factors. However, data regarding the relationship between SSB consumption and metabolic risk factors are insufficient in Chinese children. Hence, we aimed to explore the association between SSB consumption and cardio-metabolic risk factors in children aged 7–18 years living in South China.

Methods: A cross-sectional study was conducted in a total of 2,032 children aged 7–18 years were enrolled, including 1,013 boys and 1,019 girls. Based on a multistage cluster sampling, five elementary and four secondary schools in Guangzhou, China were included. Fasting blood glucose levels, lipid profiles, and anthropometric characteristics were evaluated. Information on demography, dietary, and physical activities were self-reported.

Results: Overall, 34.7% participants were non-drinkers and 21.6% consumed more than 120 mL/day SSB. The body mass index (19.43±0.18 kg/m²) and triglyceride concentration (0.96±0.03 mmol/L) were higher and high-density lipoprotein concentration (1.32±0.31 mmol/L) was lower in consumers than in non-consumers (all P＜0.001). Furthermore, in contrast to non-consumers, the adjusted odds ratio of SSB consumption more than 120 mL/day was 2.08 (95% CI: 1.21–3.54) for obesity, 1.83 (95% CI: 1.25–2.69) for abdominal obesity, and 1.70 (95% CI: 1.02–3.06) for hypertriglyceridemia in consumers.

Conclusion: A positive association between SSB consumption and the risks of obesity and hypertriglyceridemia was observed in children living in South China, which suggests that high SSB consumption enhances the risk of cardio-metabolic risk factors and the consequent cardio-metabolic diseases.

Aim: Smoking cessation is particularly important for maintaining health; however, the subsequent risk of an increased body weight is of major concern. The present study investigated the influence of smoking cessation on the incidence of metabolic syndrome and its components in the Japanese general population.

Methods: This study enrolled individuals without metabolic syndrome or a history of smoking via our annual health checkup program (n=5,702, 55.2±11.5 years). Participants were divided into three groups mentioned below and followed up with the endpoint being the development of metabolic syndrome: (1) subjects who had never smoked and did not smoke during the observation period (non-smoker); (2) those who continued smoking during the observation period (continuous smoker); and (3) those who ceased smoking during the observation period (smoking cessation).

Results: During the observation period (median 1,089 days), 520 subjects developed metabolic syndrome, and Kaplan–Meier analysis showed a higher incidence of metabolic syndrome in the smoking cessation group than in the other groups. Smoking cessation was confirmed as an independent predictor of the new onset of metabolic syndrome by multivariate Cox proportional hazard analysis after adjustment. Subjects only from the smoking cessation group showed a significant deterioration in metabolic factors during the study in correlation with an increased waist circumference after smoking cessation.

Conclusions: Smoking cessation without instruction could be followed by the development of metabolic syndrome, and the incidence of metabolic syndrome might reduce the benefit obtained from smoking cessation. Therefore, further educational outreach is needed to prevent the progression of metabolic syndrome during the course of smoking cessation.