Imaging Atherosclerosis in Diabetes: Current State

Value of transcranial color-code Doppler in evaluating intracranial atherosclerotic stenosis in patients with diabetes mellitus type 2: a comparison of transcranial Doppler and computed tomography angiography

BACKGROUND

There are several imaging assessment methods for intracranial atherosclerotic stenosis (ICAS). This study investigated the most efficient method by which to diagnose ICAS in patients with diabetes mellitus.

METHODS

One hundred seven patients with type 2 diabetes mellitus were enrolled as the experimental group and 68 healthy subjects were designated as the control group. The experimental group was examined with transcranial color-code Doppler (TCCD) and transcranial Doppler (TCD). Sixty-five patients in the experimental group were diagnosed by computed tomography angiography (CTA) on a voluntary basis. The 68 subjects in the control group were examined by TCCD alone.

RESULTS

Based on TCCD examinations, the ICAS positivity rate was 71.0% (76/107) in the experimental group, which was greater than the 42.6% (29/68) in the control group (χ2 = 13.954, P＜0.001). The middle cerebral artery was most frequently affected by ICAS (χ2 = 4.684，P=0.030), with a higher incidence of moderate and severe stenosis (χ2 =4.510，P=0.034). The ICAS positivity rate was 64.6% (42/65) by TCCD, 75.4% (49/65) by CTA, and 53.8% (35/30) by TCD. There was a statistically significant difference between the TCCD and CTA (χ2=1.795, P=0.180) and between the TCD and CTA (χ2=6.594, P=0.010) positivity rates.

CONCLUSIONS

ICAS is expected to occur in patients with diabetes mellitus more often than healthy subjects, and to involve the middle cerebral artery with moderate-to-severe stenosis. The ICAS positivity rate evaluated by TCCD was lower than CTA and higher than TCD.

miR-217 alleviates high-glucose-induced vascular smooth muscle cell dysfunction via regulating ROCK1

MicroRNA-217 (miR-217) has been recently reported to be abnormally expressed during atherosclerosis. Nonetheless, it still remains unknown whether miR-217 can regulate inflammation, proliferation, migration, and apoptosis of vascular smooth muscle cells (VSMCs) in high-glucose condition. Sprague Dawley rats were used for establishing diabetic animal models. miR-217 mimics and miR-217 inhibitors were transfected into VSMCs. The miR-217 and ROCK1 expressions were measured by quantitative reverse transcription-polymerase chain reaction and Western blot. VSMCs' proliferation, migration, cell cycle, and apoptosis were validated using the Cell Counting Kit-8 assay, Transwell assay, and flow cytometry analysis, respectively. The binding sites between miR-217 and the 3'-untranslated region of ROCK1 were predicted via miRanda, PicTar, TargetScan, and microT databases, and the targeting relationship was confirmed by dual-luciferase reporter experiments. miR-217 was found to be upregulated in VSMCs treated by high glucose and aorta VSMCs of diabetic rats. Transfection of miR-217 mimics significantly induced VSMCs cycle arrest, inhibition of proliferation, reduction of migration, and enhancement of apoptosis. The bioinformatics analysis and dual-luciferase reporter experiments identified ROCK1 as a direct target of miR-217. miR-217 inhibits excessive proliferation and migration of VSMCs induced by high glucose by targeting ROCK1.

Toll-like receptor 4 plays a key role in advanced glycation end products-induced M1 macrophage polarization

OBJECTIVE

This study was aimed to investigate the role of Toll-like receptor 4 (TLR4) in advanced glycation end products (AGEs)- induced macrophage polarization toward M1.

METHODS

Isolated primary macrophages were exposed to prepared AGEs at concentrations of 0, 2.5, 5 and 10 μmol/L. Macrophages were also exposed to hydrogen peroxide (H₂O₂) which provided exogenous reactive oxygen species (ROS). Receptor for AGEs (RAGE) was over-expressed by a vector. Specific siRNA silencing TLR4 and inhibitor TAK-242 were used to pre-treat the macrophages. Intracellular ROS was determined by DCFH-DA. Immunofluorescence staining was used to evaluate the expression of inducible nitric oxide synthase (iNOS) which is the marker of M1 macrophage phenotype. Real-time PCR was used to assess the mRNA expression level of TLR4 and RAGE. Protein expression levels of cytoplasmic RAGE, TLR4, nuclear signal transducers and activators of transcription 1 (STAT1) and phosphorylation levels of cytoplasmic STAT1 were evaluated by Western blotting. ELISA was used to measure concentrations of interleukin 6 (IL6), IL12 and tumor necrosis factor (TNF)α in supernatant of cell culture medium of macrophages.

RESULTS

AGEs significantly elevated intracellular ROS generation, expression levels of iNOS, cytoplasmic RAGE, TLR4, nuclear STAT1, phosphorylation levels of cytoplasmic STAT1, as well as IL6, IL12 and TNFα contents in a concentration-dependent manner. TLR4 silencing and inhibitor pre-treatment reduced expression levels of cytoplasmic RAGE, TLR4, phosphorylation of STAT1 and nuclear STAT1 in AGEs-exposed macrophages without affecting RAGE expression and intracellular ROS production levels. RAGE over-expression elevated both ROS and TLR4 expression levels in macrophages. TLR4 expression elevation was also found in H₂O₂-treat macrophages.

CONCLUSION

AGEs induced macrophage polarization toward M1 via activating RAGE/ROS/TLR4/STAT1 signaling pathway.

Asymptomatic coronary artery disease in a Norwegian cohort with type 2 diabetes: a prospective angiographic study with intravascular ultrasound evaluation

Aims

The prevalence of asymptomatic coronary artery disease (CAD) in type 2 diabetes (T2D) is unclear. We investigated the extent and prevalence of asymptomatic CAD in T2D patients by utilizing invasive coronary angiography (ICA) and intravascular ultrasound (IVUS), and whether CAD progression, evaluated by ICA, could be modulated with a multi-intervention to reduce cardiovascular (CV) risk.

Methods

Fifty-six T2D patients with ≥ 1 additional CV risk factor participated in a 2 year randomized controlled study comparing hospital-based multi-intervention (multi, n = 30) versus standard care (stand, n = 26), with a pre-planned follow-up at year seven. They underwent ICA at baseline and both ICA and IVUS at year seven. ICA was described by conventional CAD severity and extent scores. IVUS was described by maximal intimal thickness (MIT), percent and total atheroma volume and compared with individuals without T2D and CAD (heart transplant donors who had IVUS performed 7–11 weeks post-transplant, n = 147).

Results

Despite CV risk reduction in multi after 2 years intervention, there was no between-group difference in the progression of CAD at year seven. Overall, the prevalence of CAD defined by MIT ≥ 0.5 mm in the T2DM subjects was 84%, and as compared to the non-T2DM controls there was a significantly higher atheroma burden (mean MIT, PAV and TAV in the T2D population were 0.75 ± 0.27 mm, 33.8 ± 9.8% and 277.0 ± 137.3 mm³ as compared to 0.41 ± 0.19 mm, 17.8 ± 7.3% and 134.9 ± 100.6 mm³ in the reference population).

Conclusion

We demonstrated that a 2 year multi-intervention, despite improvement in CV risk factors, did not influence angiographic progression of CAD. Further, IVUS revealed that the prevalence of asymptomatic CAD in T2D patients is high, suggesting a need for a broader residual CV risk management using alternative approaches.

Trial registration Clinical trials.gov id: NCT00133718 (https://clinicaltrials.gov/ct2/show/NCT00133718)

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0832-2) contains supplementary material, which is available to authorized users.

Noninvasive Coronary Plaque Imaging

Early identification of high-risk or vulnerable atherosclerotic plaques prone to rupture and performing preemptive therapy prior to catastrophic cardiovascular events are optimal goals of plaque imaging. Despite the advances in imaging modalities to identify vulnerable characteristics, the predictive value of the imaging techniques in the clinical setting is still developing. In this regard, reliable and high-sensitive imaging modalities identifying vulnerable plaque characters that may lead to future cardiovascular events will be useful. In this review article, we describe a current non-invasive plaque imaging technique to identify high-risk coronary plaque features.

Insulin resistance, blood glucose and inflammatory cytokine levels are risk factors for cardiovascular events in diabetic patients complicated with coronary heart disease

This study was designed to investigate the relation of insulin resistance, blood glucose and inflammatory cytokines with cardiovascular events in diabetic patients complicated with coronary heart disease (CHD). A total of 120 patients with diabetes mellitus type 2 (T2DM) complicated with CHD admitted to Jinan Central Hospital from January 2015 to March 2016 were enrolled in this study. There were 60 cases complicated with cardiovascular events and 60 had no history of cardiovascular events; there were 40 cases with abnormal blood glucose, 40 with insulin resistance and 40 with elevated inflammatory cytokines. Changes in the levels of blood glucose, fasting serum insulin and inflammatory cytokines as well as changes in the homeostasis model assessment of insulin resistance indexes (HOMA-IR) were recorded and compared among groups of patients. Besides, changes in the Global Registry of Acute Coronary Events (GRACE) risk score and the incidence rate of cardiovascular events were also detected and multivariate logistic regression analysis was conducted so as to identify relevant risk factors. Our results showed the fasting blood glucose and the 2 h postprandial blood glucose levels in the non-cardiovascular event group were lower than those in the cardiovascular event group (P<0.05). However, levels of fasting serum insulin and HOMA-IR in the non-cardiovascular event group were significantly higher than those in the cardiovascular event group (P<0.05). Additionally, levels of tumor necrosis factor-α (TNF-α), interleukin-6 and C-reactive protein in the non-cardiovascular event group were significantly lower than those in the cardiovascular event group (P<0.05). Moreover, GRACE risk scores in patients with elevated inflammatory cytokines were higher than those in patients with insulin resistance and those in patients with blood glucose abnormalities (P<0.05). The incidence rate of cardiovascular events in patients with blood glucose abnormalities was lower than that in patients with insulin resistance and that in patients with elevated inflammatory cytokines. There was a positive correlation between TNF-α and HOMA-IR (P<0.05), and between HOMA-IR and the GRACE risk score (P<0.05). Blood glucose abnormalities, insulin resistance and inflammatory cytokines were all independent risk factors for cardiovascular events. Based on our findings, stronger inflammatory responses in patients with T2DM complicated with CHD lead to higher incidence rates of cardiovascular events. Besides that, elevated blood glucose and insulin resistance levels are also independent risk factors for cardiovascular events.

Brazilian guidelines on prevention of cardiovascular disease in patients with diabetes: a position statement from the Brazilian Diabetes Society (SBD), the Brazilian Cardiology Society (SBC) and the Brazilian Endocrinology and Metabolism Society (SBEM)

BACKGROUND

Since the first position statement on diabetes and cardiovascular prevention published in 2014 by the Brazilian Diabetes Society, the current view on primary and secondary prevention in diabetes has evolved as a result of new approaches on cardiovascular risk stratification, new cholesterol lowering drugs, and new anti-hyperglycemic drugs. Importantly, a pattern of risk heterogeneity has emerged, showing that not all diabetic patients are at high or very high risk. In fact, most younger patients who have no overt cardiovascular risk factors may be more adequately classified as being at intermediate or even low cardiovascular risk. Thus, there is a need for cardiovascular risk stratification in patients with diabetes. The present panel reviews the best current evidence and proposes a practical risk-based approach on treatment for patients with diabetes.

MAIN BODY

The Brazilian Diabetes Society, the Brazilian Society of Cardiology, and the Brazilian Endocrinology and Metabolism Society gathered to form an expert panel including 28 cardiologists and endocrinologists to review the best available evidence and to draft up-to-date an evidence-based guideline with practical recommendations for risk stratification and prevention of cardiovascular disease in diabetes. The guideline includes 59 recommendations covering: (1) the impact of new anti-hyperglycemic drugs and new lipid lowering drugs on cardiovascular risk; (2) a guide to statin use, including new definitions of LDL-cholesterol and in non-HDL-cholesterol targets; (3) evaluation of silent myocardial ischemia and subclinical atherosclerosis in patients with diabetes; (4) hypertension treatment; and (5) the use of antiplatelet therapy.

CONCLUSIONS

Diabetes is a heterogeneous disease. Although cardiovascular risk is increased in most patients, those without risk factors or evidence of sub-clinical atherosclerosis are at a lower risk. Optimal management must rely on an approach that will cover both cardiovascular disease prevention in individuals in the highest risk as well as protection from overtreatment in those at lower risk. Thus, cardiovascular prevention strategies should be individualized according to cardiovascular risk while intensification of treatment should focus on those at higher risk.