Atherosclerosis and Vascular Biologic Responses to Estrogens: Histologic, Immunohistochemical, Biochemical, and Molecular Methods

Atherosclerotic Lesion of the Carotid Artery in Indonesian Cynomolgus Monkeys Receiving a Locally Sourced Atherogenic Diet

The atherosclerotic lesion is a principal hallmark of atherosclerotic animal models. This study aimed to assess lesions of the carotid artery in Indonesian cynomolgus monkeys exposed to an IPB-1 atherogenic diet. A total of 20 adult male cynomolgus monkeys received the local IPB-1 diet for two years. Blood lipid profiles, morphology, and carotid ultrasound of monkeys were measured. Nine of them were euthanized to confirm atherosclerotic lesions. Common carotid arteries (CCA) and carotid bifurcation (BIF) samples were collected and stained using Verhoef-van Giessen and CD68 immunohistochemistry. The results reveal the presence of severe atherosclerosis plaques in six out of nine animals (66.7%) corresponding to intermediately and hyper-responsive groups. The hyper-responsive group displayed the highest response in the developing intimal area (IA) at the CCA (0.821 mm²), whereas the hyporesponsive group had the smallest IA (0.045 mm²) (p = 0.0001). At the BIF, the hyporesponsive group showed the smallest IA (p = 0.001), but there was no difference between the intermediately and hyper-responsive groups (p = 0.312). The macrophage marker CD68 was also expressed on the cartotid of the intermediately and hyper-responsive groups. These results indicate that severe atherosclerotic lesions with high infiltration of macrophages were formed in the carotid arteries of intermediately and hyper-responsive Indonesian cynomolgus monkeys fed with the local atherogenic diet IPB-1 over two years, thus confirming atherosclerosis in a nonhuman primate model.

International Harmonization of Nomenclature and Diagnostic Criteria (INHAND): Non-proliferative and Proliferative Lesions of the Non-human Primate (M. fascicularis)

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions Project (www.toxpath.org/inhand.asp) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in most tissues and organs from the nonhuman primate used in nonclinical safety studies. Some of the lesions are illustrated by color photomicrographs. The standardized nomenclature presented in this document is also available electronically on the internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous lesions as well as lesions induced by exposure to test materials. Relevant infectious and parasitic lesions are included as well. A widely accepted and utilized international harmonization of nomenclature for lesions in laboratory animals will provide a common language among regulatory and scientific research organizations in different countries and increase and enrich international exchanges of information among toxicologists and pathologists.

Atherogenic Index of Plasma, Triglyceride-Glucose Index and Monocyte-to-Lymphocyte Ratio for Predicting Subclinical Coronary Artery Disease

BACKGROUND

The atherogenic index of plasma (AIP), triglyceride-glucose (TyG) index, and monocyte-to-lymphocyte ratio (MLR) are strongly associated with atherogenesis of the coronary artery. This study aimed to investigate the association of the AIP, TyG index, and MLR with subclinical coronary artery disease (CAD) and evaluate their ability to predict subclinical CAD.

METHODS

A total of 697 asymptomatic patients were enrolled in this study and assigned to the subclinical CAD group (n=332) and control group (n=365). The clinical data, coronary artery calcification score, and calculated AIP, TyG index, and MLR were collected by graduate students in the cardiology division. Multivariate logistic regression models were set up to assess the risk factors for subclinical CAD.

RESULTS

The AIP, TyG index and MLR values were higher in the subclinical CAD group than in the control group (all P<0.05). In addition to the classic independent clinical risk factors, increased AIP, TyG index and MLR values were all independent risk factors for subclinical CAD (all P<0.05). The AUCs were higher after combining clinical risk factors than the AIP, TyG index, or MLR alone (all P<0.05).

CONCLUSIONS

The AIP, TyG index and MLR are independent risk factors for subclinical CAD, which can be useful for improving the diagnosis and prevention of CAD.

Association of lymphocyte-to-monocyte ratio with total coronary plaque burden in patients with coronary artery disease

BACKGROUND

Lymphocyte-to-monocyte ratio (LMR) is involved in all stages of coronary atherosclerosis and related to coronary artery disease (CAD). However, the correlation between LMR and the coronary plaque burden of CAD is not clearly elucidated. Therefore, this study aimed to investigate their correlation in patients with CAD.

METHODS

A total of 1953 consecutive eligible inpatients with suspected CAD were retrospectively included in this study. They were assigned into CAD (n = 564) and non-CAD groups (n = 1389). All patients underwent coronary computed tomographic angiography to evaluate coronary stenosis and coronary artery calcification (CAC). Spearman's tests were used to analyze the correlation between CAC score and LMR. Multivariate logistic regression models were set up to assess the risk factors of CAD.

RESULTS

Patients with CAD had lower LMR value than patients without CAD (P = 0.001). LMR was negatively correlated with CAC score and was an independent risk factor of CAC score (P < 0.05). Multivariate logistic regression model showed that LMR ≤4.8 was a newly independent risk factor of CAD (all P < 0.05). Additionally, the new risk score model was compared with the Framingham model and showed that NRI was 4.9%, which proved that the new risk score model improved the prediction capability of CAD.

CONCLUSION

LMR ≤4.8 is a new independent risk factor of CAD. LMR value was negatively correlated with CAC score and could be used as a new marker to evaluate the coronary plaque burden of CAD.

Relationship between monocyte/lymphocyte ratio and non-culprit plaque vulnerability in patients with acute coronary syndrome: An optical coherence tomography study

The importance of monocyte/lymphocyte ratio (MLR) has been indicated in the initiation and progression of coronary artery disease. However, few previous researches demonstrated the relationship between MLR and plaque vulnerability. We aimed to investigate coronary non-culprit plaque vulnerability in patients with acute coronary syndrome (ACS) by optical coherence tomography (OCT).A total of 72 ACS patients who underwent coronary angiography and OCT test in Beijing Anzhen Hospital were included in this retrospective study. The plaque vulnerability and plaque morphology were assessed by OCT.The non-culprit plaque in high MLR group exhibited more vulnerable features, characterizing as thinner thickness of fibrous cap (P = .013), greater maximum lipid core angle (P = .010) and longer lipid plaque length (P = .041). A prominently negative liner relation was found between MLR and thickness of fibrous cap (R = -0.225, P = .005). Meanwhile, the proportion of OCT-detected thin cap fibro-atheroma (TCFA) (P = .014) and plaque rupture (P = .017) were higher in high MLR group. Most importantly, multivariable logistic regression analysis showed MLR level was identified as an independent contributor to the presence of TCFA (OR:3.316, 95%: 1.448-7.593, P = .005). MLR could differentiate TCFA with a sensitivity of 60.0% and a specificity of 85.1%.Circulating MLR level has potential value in identifying the presence of vulnerable plaque in patients with ACS. MLR, as a non- invasive biomarker of inflammation, may be valuable in revealing plaque vulnerability.

Menopausal hormone therapy and heart disease prevention: desired or valid?

Cardiovascular diseases are the main cause of death for women in older age groups. For many decades, specialists have tried to prevent their development by the use of estrogen. The review of the literature presents current data on the effect of menopausal hormone therapy (MHT) on the risk of cardiovascular complications. The results of the main randomized clinical and observational studies in this area, conducted over several decades, are discussed. We described the concept of “window of opportunities”, in accordance with which an improvement in cardiovascular prognosis can be expected only at the onset of MHT in women under the age of 60 years in early postmenopause (menopause duration <10 years). There are experimental and clinical data explaining the different effects of estrogen on the cardiovascular prognosis in women of various age groups and different duration of postmenopause. The recommendations given in the review on the use of MHT are based on modern international guidelines.

Monocyte/lymphocyte ratio predicts the severity of coronary artery disease: a syntax score assessment

Background

We aimed to explore whether monocyte to lymphocyte ratio (MLR) provides predictive value of the lesion severity in patients with coronary artery disease (CAD).

Methods

Five hundred forty-three patients undergoing coronary angiography were analyzed in this retrospective study. Patients with coronary stenosis were divided into three groups on the basis of Syntax score. The control group consisted of patients with normal coronary arteries. MLR was calculated by dividing monocytes count by lymphocytes count obtained from routine blood examination. Multivariate logistic analysis was used to assess risk factors of CAD. Ordinal logistic regression analysis was used to assess the relationship between MLR and the lesion severity of coronary arteries.

Results

MLR was found to be an independent risk factor of the presence of CAD (OR: 3.94, 95% CI: 1.20–12.95) and a predictor of the lesion severity (OR: 2.05, 95% CI: 1.15–3.66). Besides, MLR was positively correlated with Syntax score(r = 0.437, p < 0.001). In the receiver-operating characteristic (ROC) curve analysis, MLR, with an optimal cut-off value of 0.25, predicted the severe coronary lesion with a sensitivity of 60.26% and specificity of 78.49%.

Conclusions

MLR was an independent risk factor of the presence of CAD, and a predictor of the lesion severity. Compared to neutrophil to lymphocyte ratio (NLR), MLR has better performance to reflect the severity of coronary lesion.

Late Effects of Total-Body Gamma Irradiation on Cardiac Structure and Function in Male Rhesus Macaques

Heart disease is an increasingly recognized, serious late effect of radiation exposure, most notably among breast cancer and Hodgkin's disease survivors, as well as the Hiroshima and Nagasaki atomic bomb survivors. The purpose of this study was to evaluate the late effects of total-body irradiation (TBI) on cardiac morphology, function and selected circulating biomarkers in a well-established nonhuman primate model. For this study we used male rhesus macaques that were exposed to a single total-body dose of ionizing gamma radiation (6.5-8.4 Gy) 5.6-9.7 years earlier at ages ranging from ∼3-10 years old and a cohort of nonirradiated controls. Transthoracic echocardiography was performed annually for 3 years on 20 irradiated and 11 control animals. Myocardium was examined grossly and histologically, and myocardial fibrosis/collagen was assessed microscopically and by morphometric analysis of Masson's trichrome-stained sections. Serum/plasma from 27 irradiated and 13 control animals was evaluated for circulating biomarkers of cardiac damage [N-terminal pro B-type natriuretic protein (nt-proBNP) and troponin-I], inflammation (CRP, IL-6, MCP-1, sICAM) and microbial translocation [LPS-binding protein (LBP) and sCD14]. A higher prevalence of histological myocardial fibrosis was observed in the hearts obtained from the irradiated animals (9/14) relative to controls (0/3) (P = 0.04, χ(2)). Echocardiographically determined left ventricular end diastolic and systolic diameters were significantly smaller in irradiated animals (repeated measures ANOVA, P < 0.001 and P < 0.008, respectively). Histomorphometric analysis of trichrome-stained sections of heart tissue demonstrated ∼14.9 ± 1.4% (mean ± SEM) of myocardial area staining for collagen in irradiated animals compared to 9.1 ± 0.9 % in control animals. Circulating levels of MCP-1 and LBP were significantly higher in irradiated animals (P < 0.05). A high incidence of diabetes in the irradiated animals was associated with higher plasma triglyceride and lower HDLc but did not appear to be associated with cardiovascular phenotypes. These results demonstrate that single total-body doses of 6.5-8.4 Gy produced long-term effects including a high incidence of myocardial fibrosis, reduced left ventricular diameter and elevated systemic inflammation. Additional prospective studies are required to define the time course and mechanisms underlying radiation-induced heart disease in this model.