Detection of the "midband" lipoprotein in patients with coronary artery spasm

Pemafibrate decreases triglycerides and small, dense LDL, but increases LDL-C depending on baseline triglycerides and LDL-C in type 2 diabetes patients with hypertriglyceridemia: an observational study

Background

Pemafibrate, a selective PPARα modulator, has the beneficial effects on serum triglycerides (TGs) and very low density lipoprotein (VLDL), especially in patients with diabetes mellitus or metabolic syndrome. However, its effect on the low density lipoprotein cholesterol (LDL-C) levels is still undefined. LDL-C increased in some cases together with a decrease in TGs, and the profile of lipids, especially LDL-C, during pemafibrate administration was evaluated.

Methods

Pemafibrate was administered to type 2 diabetes patients with hypertriglyceridemia. Fifty-one type 2 diabetes patients (mean age 62 ± 13 years) with a high rate of hypertension and no renal insufficiency were analyzed. Pemafibrate 0.2 mg (0.1 mg twice daily) was administered, and serum lipids were monitored every 4–8 weeks from 8 weeks before administration to 24 weeks after administration. LDL-C was measured by the direct method. Lipoprotein fractions were measured by electrophoresis (polyacrylamide gel, PAG), and LDL-migration index (LDL-MI) was calculated to estimate small, dense LDL.

Results

Pemafibrate reduced serum TGs, midband and VLDL fractions by PAG. Pemafibrate increased LDL-C levels from baseline by 5.3% (− 3.8–19.1, IQR). Patients were divided into 2 groups: LDL-C increase of > 5.3% (group I, n = 25) and < 5.3% (group NI, n = 26) after pemafibrate. Compared to group NI, group I had lower LDL-C (2.53 [1.96–3.26] vs. 3.36 [3.05–3.72] mmol/L, P = 0.0009), higher TGs (3.71 [2.62–6.69] vs. 3.25 [2.64–3.80] mmol/L), lower LDL by PAG (34.2 [14.5, SD] vs. 46.4% [6.5], P = 0.0011), higher VLDL by PAG (28.2 [10.8] vs. 22.0% [5.2], P = 0.0234), and higher LDL-MI (0.421 [0.391–0.450] vs. 0.354 [0.341–0.396], P < 0.0001) at baseline. Pemafibrate decreased LDL-MI in group I, and the differences between the groups disappeared. These results showed contradictory effects of pemafibrate on LDL-C levels, and these effects were dependent on the baseline levels of LDL-C and TGs.

Conclusions

Pemafibrate significantly reduced TGs, VLDL, midband, and small, dense LDL, but increased LDL-C in diabetes patients with higher baseline TGs and lower baseline LDL-C. Even if pre-dose LDL-C remains in the normal range, pemafibrate improves LDL composition and may reduce cardiovascular disease risk.

Utility of the Japan arteriosclerosis longitudinal study score for identifying a high risk for vasospastic angina

OBJECTIVE

The aim of this study was to investigate whether the Japan Arteriosclerosis Longitudinal Study (JALS) score, which is calculated from the traditional atherosclerotic coronary risk, is associated with the incidence of coronary vasospasms.

METHODS

We performed vasospasm provocation tests with acetylcholine in 109 patients referred to our hospital due to suspected vasospastic angina and subsequently calculated the atherosclerotic risk score according to the JALS score. Consequently, coronary vasospasms were evoked in 51 patients. The patients were divided into three groups according to the tertile of the JALS score: 1st, <28, n=36; 2nd, 28-41, n=36, 3rd, >42, n=37. The third tertile exhibited the greatest risk for vasospasms. A multivariate logistic regression analysis revealed that the JALS score (odds ratio: 1.686, p<0.05) was independently associated with the incidence of vasospasms.

CONCLUSION

The JALS score can serve as a useful tool for evaluating patients with suspected coronary vasospasms.

Increased intima-media thickness of the carotid artery in Japanese female type 2 diabetic patients with 'midband lipoprotein'

Among a number of different lipoprotein abnormalities, 'midband lipoprotein' migrating at a position between LDL and VLDL on polyacrylamide gel electrophoresis (PAGE), is an atherogenic lipoprotein and intima-media thickness (IMT) of the carotid artery is a useful marker of atherosclerotic diseases. The present study evaluated relationships between the presence of 'midband lipoprotein' and carotid IMT in subjects with type 2 diabetes. The average IMT of the carotid artery was determined from the means of maximal thicknesses of both left and right common carotid arteries, carotid bulb, and internal carotid artery using ultrasound B mode imaging in 118 Japanese patients (72 men, 46 women) and 43 healthy controls. Multivariate regression analyses indicated that the duration of diabetes and presence of 'midband lipoprotein' were independent determinants of carotid artery IMT in 46 female subjects with diabetes, and these subjects were then subclassified into midband-positive (n=24) and midband-negative (n=22) groups. IMT of the carotid artery was significantly different between midband-positive (0.98+/-0.32mm) and midband-negative (0.79+/-0.17mm) groups (P=0.02). These findings suggest that 'midband lipoprotein' is a possible risk factor for IMT of the carotid artery in Japanese female type 2 diabetic patients.

Cluster differentiation-36 deficiency type 1 and acute coronary syndrome without major cardiovascular risk factors: case report

A 45-year-old man without major coronary risk factors, including hypertension, diabetes mellitus, smoking, hypercholesterolemia, hyperuricemia, or a family history of early cardiovascular disease, presented with acute coronary syndrome. Angiography showed thrombus formation in segment 7 of the left anterior descending coronary artery, and percutaneous coronary intervention was successful after implantation of a bare metal stent. Scintigraphy showed the absence of 123I-beta-methyl-iodophenyl pentadecanoic acid accumulation in the myocardium. Flow cytometric analysis of platelets and monocytes showed the absence of cluster differentiation (CD)-36 expression. These findings are consistent with a diagnosis of CD36 deficiency type 1, which might be associated with cardiovascular disease. The patient had no apparent major coronary risk factors except for insulin resistance and an abnormal lipoprotein profile. The findings suggest that in this case the CD36 deficiency type 1 was the pathogenic mechanism of acute coronary syndrome relative to insulin resistance and modification of the lipid profile.

High remnant lipoprotein levels in patients with variant angina

BACKGROUND

Dyslipidemia with increased oxidative stress but without elevation of low-density lipoprotein cholesterol has been recently implicated in the pathogenesis of coronary vasospasm.

HYPOTHESIS

Disordered triglyceride-rich lipoprotein metabolism may be linked to the genesis of coronary artery spasm.

METHODS

Both serum remnant lipoprotein (RLP) and alpha-tocopherol levels were determined in 18 patients with the active stage of variant angina (VA), in 16 patients with the inactive stage of variant angina (IVA), and in 19 control subjects (CONTROL).

RESULTS

The RLP levels were significantly (p < 0.05) higher in VA (6.4 +/- 2.7 mg/dl) than in IVA (4.4 +/- 1.5 mg/dl). In contrast, alpha-tocopherol levels were significantly lower in VA than that in CONTROL. Serum trigyceride levels were not significantly different among the study groups, although serum high-density lipoprotein cholesterol levels were significantly lower in VA than in CONTROL. Smoking was significantly (p < 0.05) more prevalent in VA (72%) than in IVA (25%) and CONTROL (37%). Serum RLP levels correlated positively with triglyceride levels (R = 0.73) and correlated inversely with alpha-tocopherol levels (R = -0.31) significantly in all study subjects.

CONCLUSIONS

Patients with active stage of variant angina had higher RLP levels than inactive patients with variant angina and lower alpha-tocopherol levels than control subjects. Disordered triglyceride-rich lipoprotein metabolism with increased oxidative stress appears to be linked to the activity of coronary vasospasm, suggesting a possible role in its pathogenesis.

Coronary vasospasm and the regulation of coronary blood flow

Under physiologic conditions, epicardial arteries contribute minimally to coronary vascular resistance. However, in the presence of endothelial dysfunction, stimuli that normally produce vasodilation may instead cause constriction. Examples include neural release of acetylcholine or norepinephrine, platelet activation and production of serotonin and thrombin, and release of local factors such as bradykinin. This shift from a primary endothelial-mediated vasodilator influence to one of endothelial dysfunction and unchecked vasoconstriction is precisely the milieu in which coronary vasospasm is observed. This condition, which typically occurs during periods of relatively sedentary activity, is associated with focal and transient obstruction of an epicardial arterial segment resulting in characteristic echocardiographic changes and symptoms of myocardial ischemia. This review highlights the current understanding of mechanisms regulating the coronary circulation during health and examines the pathophysiologic changes that occur with coronary spasm. Genetic and other predisposing conditions are addressed, as well as novel therapies based on recent mechanistic insights of the coronary contractile dysfunction associated with coronary spasm.

Low density lipoprotein particles are small in patients with coronary vasospasm

Increased lipid oxidative stress has been recently implicated in the pathogenesis of coronary artery spasm. Small, dense LDL with high susceptibility to oxidation may be linked to the genesis of coronary vasospasm. The relative migratory distance of the predominant densitometric peak of LDL from that of VLDL to that of HDL in a 3% polyacrylamide gel electrophoresis was determined as a measure of LDL particle size in 49 patients with coronary spastic angina (CSA), in 56 patients with stable effort angina and a significant coronary artery stenosis (SEA) and also in 40 control subjects without coronary artery disease (Control). The incidence of detection of small, dense LDL (particle diameter <25.5 nm) or a relative migratory distance above 0.36 was significantly higher in CSA (57%) and also in SEA (39%) than in Control (20%). In SEA, a significantly higher serum level of triglyceride was noted in the subgroup with the small, dense LDL as compared with the subgroup without. In contrast, in CSA, the serum level of triglyceride was not significantly different between the subgroups with and without the small, dense LDL, although significantly lower serum levels of both HDL-cholesterol and alpha-tocopherol were noted in the former. In 16 patients of CSA, the detection of the small, dense LDL was significantly decreased after a >6-month angina-free period (69-->31%). We conclude that patients with coronary spastic angina had smaller LDL particles, associated not with hypertriglyceridemia but low serum levels of both HDL-cholesterol and vitamin E. Dyslipidemia with small, dense LDL may be related to the genesis of coronary vasospasm.