Intermittent cold stress enhances features of atherosclerotic plaque instability in apolipoprotein E-deficient mice

Effects of Prolonged Cold Stress on Vascular Function in Guinea Pigs With Atherosclerosis

RESEARCH OBJECTIVE

This study explored the effects of long-term cold stress (CS) on aortic vascular function in guinea pigs.

RESEARCH METHODS

Hartley guinea pigs (n = 32) were divided into the following groups: atherosclerosis (AS), CS, and menthol-stimulated (M), and control (C). On days 1, 15, 30, 45, and 60, guinea pigs in the AS, CS, and M groups were intraperitoneally injected with bovine serum albumin. The C group was provided with maintenance feed and room temperature water. The AS group was provided with a high-fat diet and room temperature water. The CS group was maintained in a refrigerator at 4°C, while providing a high-fat diet and iced water. The M group was administered menthol solution, and provided with a high-fat diet and room temperature water. The modeling period lasted for 120 days. On day 121, abdominal aortic sera and aortic samples were obtained after intraperitoneal injection of sodium pentobarbital. Blood rheology tests were conducted to assess blood adhesion, biochemical tests to assess lipid levels, and enzyme-linked immunosorbent assays to detect serum nuclear factor-κB, tumor necrosis factor-α, and interleukin-1β, and endothelial nitric oxide synthase, nitric oxide, and endothelin-1 (ET-1) in aortic tissue. Hematoxylin and eosin and oil red O staining were used to examine pathologic changes in the aorta, Western blotting to detect transient receptor potential melastatin 8 and protein kinase G protein expression, quantitative polymerase chain reaction was used to measure VCAM-1 mRNA expression level.

RESEARCH FINDINGS

Prolonged exposure to CS exacerbated lipid-metabolism disorders in guinea pigs fed a high-fat diet, increased aortic vascular cell adhesion, and exacerbated vascular inflammation, leading to endothelial injury, ultimately worsening pathologic changes associated with aortic atherosclerosis.

Global, regional, and national burdens of hypertensive heart disease from 1990 to 2019 ：A multilevel analysis based on the global burden of Disease Study 2019

Aim

This study aimed to describe the prevalence, deaths, and disability-adjusted life-years (DALYs) of hypertensive heart disease (HHD) at the global, regional, and national levels and analyze epidemiological trends.

Method

We extracted global estimates of prevalence, deaths, and DALYs related to HHD in 204 countries and regions from the 2019 Global Burden of Diseases Study. Average annual percent change (AAPC) was calculated to represent temporal trends. Joinpoint regression models were used to analyze time trends from 1990 to 2019. Finally, the decomposition analysis showed the driving factors of burden changes.

Results

From 1990 to 2019, the global prevalence of HHD cases increased by 138 %, reaching 18,598,025 cases (95 % uncertainty interval [UI]: 13,544,365-24,898,411). DALYs also rose by 154 %, reaching 21,508,002 (95 % UI, 16,400,051-23,899,879). The death rate increased to 14.95 (95 % UI, 11.11-16.52) per 100,000 people. Of the five sociodemographic index (SDI) regions, the prevalence rate related to HHD was the highest in the high-middle SDI region. In contrast, the death and DALY rate related to HHD were the highest in the middle SDI region. In other regions, the prevalence rate was the highest in East Asia (548.87 per 100,000 people; 95 % UI, 395.40-747.83), and the death rate was the highest in Central Europe (42.64 per 100,000 people; 95 % UI, 30.58-49.38). At the national level, the Cook Islands had the highest prevalence rate for HHD (703.08 per 100,000 people; 95 % UI, 532.87-920.72), Bulgaria had the highest death rate (75.08 per 100,000 people; 95 % UI, 46.38-92.81), and Afghanistan had the highest DALY rate (1374.12 per 100,000 people; 95 % UI, 467.17-2020.70). High body mass index, a diet high in sodium, alcohol use, lead exposure, high temperature, and low temperature were identified as risk factors for death and DALYs related to HHD in 2019. Aging and population growth were the major drivers of prevalence, death, and DALYs. Finally, over the past 30 years, the global age-standardized prevalence rate (ASPR) of HHD has significantly risen (AAPC = 0.21 %, 95 % confidence interval [CI]: 0.17-0.24; P < 0.001), while the age-standardized deaths rate (ASDR) has shown significant declining trends (AAPC = -0.86 %, 95 % CI: 1.00 to -0.71; P < 0.001), and age-standardized DALY rates (AAPC = -1.08 %, 95 % CI: 1.23 to -0.93; P < 0.001).

Conclusion

Despite a significant decline in the global ASDR and age-standardized DALY rate of HHD over the past 30 years, the ASPR continues to rise. The burden of HHD is more heavily skewed towards non-high-income economies. Active prevention, control of risk factors, and improvement of medical protection levels to address the disease burden caused by population growth and aging are needed.

Cardiovascular disease burden attributable to non-optimal temperature: analysis of the 1990-2019 global burden of disease

AIMS

Extreme temperatures are increasingly experienced as a result of climate change. Both high and low temperatures, impacted by climate change, have been linked with cardiovascular disease (CVD). Global estimates on non-optimal temperature-related CVD are not known. The authors investigated global trends of temperature-related CVD burden over the last three decades.

METHODS AND RESULTS

The authors utilized the 1990-2019 global burden of disease methodology to investigate non-optimal temperature, low temperature- and high temperature-related CVD deaths, and disability-adjusted life years (DALYs) globally. Non-optimal temperatures were defined as above (high temperature) or below (low temperature) the location-specific theoretical minimum-risk exposure level or the temperature associated with the lowest mortality rates. Analyses were later stratified by sociodemographic index (SDI) and world regions. In 2019, non-optimal temperature contributed to 1 194 196 (95% uncertainty interval [UI]: 963 816-1 425 090) CVD deaths and 21 799 370 (95% UI: 17 395 761-25 947 499) DALYs. Low temperature contributed to 1 104 200 (95% UI: 897 783-1 326 965) CVD deaths and 19 768 986 (95% UI: 16 039 594-23 925 945) DALYs. High temperature contributed to 93 095 (95% UI: 10 827-158 386) CVD deaths and 2 098 989 (95% UI: 146 158-3 625 564) DALYs. Between 1990 and 2019, CVD deaths related to non-optimal temperature increased by 45% (95% UI: 32-63%), low temperature by 36% (95% UI: 25-48%), and high temperature by 600% (95% UI: -1879-2027%). Non-optimal temperature- and high temperature-related CVD deaths increased more in countries with low income than countries with high income.

CONCLUSION

Non-optimal temperatures are significantly associated with global CVD deaths and DALYs, underscoring the significant impact of temperature on public health.

Impact of Acute and Chronic Psychosocial Stress on Vascular Inflammation

Significance: Atherosclerosis and its complications, such as acute coronary syndromes, are the leading causes of death worldwide. A wide range of inflammatory processes substantially contribute to the initiation and progression of cardiovascular disease (CVD). In addition, epidemiological studies strongly associate both chronic stress and acute psychosocial stress with the occurrence of CVDs. Recent Advances: Extensive research during recent decades has not only identified major pathways in cardiovascular inflammation but also revealed a link between psychosocial factors and the immune system in the context of atherosclerosis. Both chronic and acute psychosocial stress drive systemic inflammation via neuroimmune interactions and promote atherosclerosis progression. Critical Issues: The associations human epidemiological studies found between psychosocial stress and cardiovascular inflammation have been substantiated by additional experimental studies in mice and humans. However, we do not yet fully understand the mechanisms through which psychosocial stress drives cardiovascular inflammation; consequently, specific treatment, although urgently needed, is lacking. Future Directions: Psychosocial factors are increasingly acknowledged as risk factors for CVD and are currently treated via behavioral interventions. Additional mechanistic insights might provide novel pharmacological treatment options to reduce stress-related morbidity and mortality. Antioxid. Redox Signal. 35, 1531-1550.

Modulation of Peripheral CD4+CD25+Foxp3+ Regulatory T Cells Ameliorates Surgical Stress-Induced Atherosclerotic Plaque Progression in ApoE-Deficient Mice

Systemic inflammation associated with major surgery rapidly accelerates atherosclerotic plaque progression in mice. Regulatory T cells (Tregs) have emerged as important modulators of atherogenesis. In coronary artery disease patients, low frequency of Tregs constitutes an independent risk factor for cardiovascular complications after non-cardiac surgery. In this exploratory analysis, we investigate whether preoperative Treg levels affect surgery-induced atherosclerotic lesion destabilization in a murine model of perioperative stress. After 9 weeks of high-cholesterol diet, atherosclerotic apolipoprotein E-deficient mice with modulated Treg levels were subjected to a 30-minute surgical procedure consisting of general isoflurane anesthesia, laparotomy and moderate blood loss. Controls underwent general anesthesia only. Brachiocephalic arteries were harvested 3 days after the intervention for histomorphological analyses of atherosclerotic plaques. Tregs were depleted by a single dose of anti-CD25 monoclonal antibody (mAb) administered 6 days prior to the intervention. Expansion of Tregs was induced by daily injections of IL-2/anti-IL-2 complex (IL-2C) on three consecutive days starting 3 days before surgery. Isotype-matched antibodies and PBS served as controls. Antibody-mediated modulation was Treg-specific. IL-2C treatment resulted in an eight-fold elevation of peripheral CD4⁺CD25⁺Foxp3⁺ Tregs compared to mice administered with anti-CD25 mAb. In mice treated with PBS and anti-CD25 mAb, surgical stress response caused a significant increase of atherosclerotic plaque necrosis (PBS: p < 0.001; anti-CD25 mAb: p = 0.037). Preoperative Treg expansion abrogated perioperative necrotic core formation (p = 0.556) and significantly enhanced postoperative atherosclerotic plaque stability compared to PBS-treated mice (p = 0.036). Postoperative plaque volume (p = 0.960), stenosis (p = 0.693), lesional collagen (p = 0.258), as well as the relative macrophage (p = 0.625) and smooth muscle cell content (p = 0.178) remained largely unaffected by preoperative Treg levels. In atherosclerotic mice, therapeutic expansion of Tregs prior to major surgery mitigates rapid effects on perioperative stress-driven atherosclerotic plaque destabilization. Future studies will show, whether short-term interventions modulating perioperative inflammation qualify for prevention of cardiovascular events associated with major non-cardiac surgery.

Socioeconomic deprivation and blood lipids in first-episode psychosis patients with minimal antipsychotic exposure: Implications for cardiovascular risk

BACKGROUND

The influence of socioeconomic deprivation on the cardiovascular health of patients with psychosis-spectrum disorders (PSD) has not been investigated despite the growing recognition of social factors as determinants of health, and the disproportionate rates of cardiovascular mortality observed in PSD. Discordant results have been documented when studying dyslipidemia -a core cardiovascular risk factor- in first-episode psychosis (FEP), before chronic exposure to antipsychotic medications. The objective of the present study is to determine the extent to which socioeconomic deprivation affects blood lipids in patients with FEP, and examine its implications for cardiovascular risk in PSD.

METHODS

Linear regression models, controlling for age, sex, exposure to pharmacotherapy, and physical anergia, were used to test the association between area-based measures of material and social deprivation and blood lipid levels in a sample of FEP patients (n = 208).

RESULTS

Social, but not material deprivation, was associated with lower levels of total and HDL cholesterol. This effect was statistically significant in patients with affective psychoses, but not in schizophrenia-spectrum disorders.

CONCLUSIONS

Contrary to other reports from the literature, the relationship between socioeconomic disadvantage and blood lipid levels was contingent on the social rather than the material aspects of deprivation. Furthermore, this association also depended on the main diagnostic category of psychosis, suggesting a complex interaction between the environment, psychopathology, and physical health. Future studies exploring health issues in psychosis might benefit from taking these associations into consideration. A better understanding of the biology of blood lipids in this context is necessary.

Plasma levels of matrix metalloproteinase-9: A possible marker for cold-induced stroke risk in hypertensive rats

The cold weather is associated with an increased occurrence of acute stroke events. However, the underlying mechanisms have not yet been fully elucidated. In the present study, we investigated whether plasma matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) levels as well as the MMP-9/TIMP-1 ratio could be used as predictor for cold-induced stroke risk in hypertensive rats. A total of 50 male rats were subjected to either control group or 2-kidney, 2-clip (2K - 2C) group (N = 25, each), After blood pressure was stabilized, rats were placed in an intelligent artificial climate chamber and maintained on a 12-h light (22 °C)/dark (4 °C) cycle for 3 days. Plasma levels of MMP-9 and TIMP-1 were measured before and after cold exposure from 50 rats by ELISA. Pretreatment plasma MMP-9 levels were significantly higher in 2K-2C rats than in the controls (P <  0.05), TIMP-1 levels were significantly lower in 2K-2C rats than in the controls (P <  0.05), pretreatment plasma MMP-9 levels were significantly higher in those with cold-induced stroke compared to those without (P <  0.05). Logistic regression analysis showed that only plasma MMP-9 levels remained independently associated with cold-induced stroke after adjusting for potential confounders (OR, 1.17; 95% CI, 1.08 to 1.32; P < 0.007). In contrast, no correlation was observed between systolic blood pressure (SBP), TIMP-1 or MMP-9/TIMP-1 ratio and the cold-induced stroke. Higher plasma MMP-9 levels are significantly correlated with cold-induced stroke in hypertensive rats treated with intermittent cold stress. Plasma MMP-9 may be as a promising biomarker to predict the risk of cold-induced stroke events in hypertensive rats.

Effects of Cold-inducible RNA-binding Protein (CIRP) on Liver Glycolysis during Acute Cold Exposure in C57BL/6 Mice

Cold-inducible RNA-binding protein (CIRP) is a stress-responsive protein involved in several signal transduction pathways required for cellular function, which are associated with apoptosis and proliferation. The present study aimed to investigate the possible effects of CIRP-mediated regulation of glucose metabolism in the liver following acute cold exposure. The livers and serum of male C57BL/6 mice were collected following cold exposure at 4 °C for 0 h, 2 h, 4 h, and 6 h. Glucose metabolic markers and the expression of glucose metabolic-related proteins were detected in the liver. Acute cold exposure was found to increase the consumption of glycogen in the liver. Fructose-1,6-diphosphate (FDP) and pyruvic acid (PA) were found to show a brief increase followed by a sharp decrease during cold exposure. Anti-apoptotic protein (Bcl-2) expression was upregulated. CIRP protein expression displayed a sequential increase with prolonged acute cold exposure time. Acute cold exposure also increased the level of protein kinase B (AKT) phosphorylation, and activated the AKT-signaling pathway. Taken together, these findings indicate that acute cold exposure increased the expression of CIRP protein, which regulates mouse hepatic glucose metabolism and maintains hepatocyte energy balance through the AKT signaling pathway, thereby slowing the liver cell apoptosis caused by cold exposure.

Inhibitory effects of Aconiti Lateralis Radix Preparata on chronic intermittent cold-induced inflammation in the mouse hypothalamus

ETHNOPHARMACOLOGICAL RELEVANCE

Aconiti Lateralis Radix Preparata (AR) is the most frequently used herb to generate heat and treat symptoms associated with coldness in Asia.

AIMS OF THE STUDY

The hypothalamus is one of the master regulators to maintain constant core body temperature. Chronic exposure to cold stress disturbs homeostatic regulation, gradually resulting in hypothalamic inflammation. This study investigate the effects of AR, on the chronic intermittent cold (CIC)-induced release of pro-inflammatory signaling molecules in the mouse hypothalamus.

MATERIALS AND METHODS

Aconiti Lateralis Radix Preparata extract (ARE) were solubilized in distilled water and diluted with saline before administration. Male ICR mice (7 weeks old, 30-32g) were divided randomly into 6 groups: (1) control, (2) cold stress, (3) ARE 30, (4) ARE 100, (5) ARE 300, and (6) ARE 1000mg/kg groups. Groups (2)-(6) were exposed to CIC stress once a day for 14 days. CIC stress was achieved by exposing the mice to 4°C and 60 ± 10% humidity for 120min once a day. Rectal temperature was measured after terminating cold stress. Cortisol levels were measured from serum. Hypothalamus tissue was used for western blot analysis, and IL-9, IL-13, PGE1, and PGE2 levels were assessed.

RESULTS

ARE treatment prevented the CIC-induced decrease in rectal temperature and increase in serum cortisol level. ARE-treated CIC-exposed mice demonstrated decrease in nuclear c-Fos levels dose-dependently compared to CIC-exposed mice. Nuclear NF-kB expression showed significant increase in CIC-exposed mice. ARE treatment significantly blunted the increase in nuclear NF-kB expression. CIC-exposed mice had significantly increased levels of both IL-9 and IL-13. Treatment with ARE suppressed the elevated IL-9 and IL-13 levels. Between control and CIC-exposed mice PGE1 levels showed no difference. However ARE (1000mg/kg)-treated CIC-exposed mice had a significant increase in PGE1 level compared to CIC-exposed mice. PGE2 levels were significantly higher in CIC-exposed mice compared to control mice. ARE treatment significantly attenuated the increase in PGE2 levels.

CONCLUSIONS

Our findings suggest CIC stress disturbs the anti-inflammatory effect of cortisol and maintenance of the body temperature. Thus AR contributes to suppress the activated proinflammatory factors, IL-9, IL-13, and PGE-2, and to increase the heat production.

Genetic expression analysis of E2F-associated phosphoprotein in stress responses in the mouse

Dysfunction of the monoaminergic system is critical in stress and anxiety disorders, but the role of each family member in the development of stress-related psychopathologies is not sufficiently understood. Eapp has been reported to be a transcriptional repressor of monoamine oxidase B (Maob) and down-regulates Maob via the Maob core promoter. In the present study, we more specifically examine the role of Eapp in stress responses by testing the hypothesis that Eapp may be involved in the occurrence and development of stress responses. Western blotting, qPCR and immunohistochemistry were used to investigate the expression variation of Eapp in hypothalamus tissue after exposure to stress. The expression of Eapp is controlled by a cis-acting quantitative trait locus (cis-eQTL). Two genes Sphk2 and Nosip, had trans-eQTLs that mapped to the location of Eapp and altered expression of these two genes was shown following siRNA knockdown of Eapp. Additionally, Mmp9, Npy, Npy5r and Maob were shown to have different expression levels in the Eapp knock-down experiments. Our data provide strong evidence that the cis-modulated gene, Eapp, is associated with stress responses, and that validated downstream targets and members of Eapp gene network may also be involved in the development of stress.

Acute and chronic psychological stress as risk factors for cardiovascular disease: Insights gained from epidemiological, clinical and experimental studies

Cardiovascular disease (CVD) remains a leading cause of death worldwide and identification and therapeutic modulation of all its risk factors is necessary to ensure a lower burden on the patient and on society. The physiological response to acute and chronic stress exposure has long been recognized as a potent modulator of immune, endocrine and metabolic pathways, however its direct implications for cardiovascular disease development, progression and as a therapeutic target are not completely understood. More and more attention is given to the bidirectional interaction between psychological and physical health in relation to cardiovascular disease. With atherosclerosis being a chronic disease starting already at an early age the contribution of adverse early life events in affecting adult health risk behavior, health status and disease development is receiving increased attention. In addition, experimental research into the biological pathways involved in stress-induced cardiovascular complications show important roles for metabolic and immunologic maladaptation, resulting in increased disease development and progression. Here we provide a concise overview of human and experimental animal data linking chronic and acute stress to CVD risk and increased progression of the underlying disease atherosclerosis.