Defects in regulation of local immune responses resulting in atherosclerosis

Protective effect of HSP27 in atherosclerosis and coronary heart disease by inhibiting reactive oxygen species

OBJECTIVE

To clarify the mechanism of heat shock protein 27 (HSP27) as a diagnostic biomarker in coronary heart disease (CHD) and atherosclerosis (AS).

METHOD

Expressions of HSP27 in patients with CHD and healthy controls were determined by enzyme-linked immunosorbent assay and the expressions of HSP27 in aortas of patients with CHD and healthy controls were measured by immunohistochemistry. Receiver operating characteristic curve was applied to assess the diagnostic performance of HSP27 in CHD. ApoE^-/- mice were included and accordingly grouped. The expressions of HSP27 in AS plaque were measured by quantitative real-time polymerase chain reaction, immunohistochemistry, and Western blot analysis. AS plaque was observed using hematoxylin and eosin staining. DHE was used to detect reactive oxygen species (ROS) levels in aortas. The expressions of mitochondrial apoptosis-related proteins were measured by Western blot analysis. Cell apoptosis was determined by TUNEL staining.

RESULTS

HSP27 was highly expressed in patients with CHD than in healthy controls ( P < 0.01). In comparison to the normal group, the model group had increased the relative positive area of HSP27 and higher expressions of HSP27, Bax, caspase-3, and apoptosis index (AI) but decreased Bcl-2 expression in AS plaque, as well as larger plaque areas and elevated ROS levels in the aorta (all P < 0.05). The HSP27-small interfering RNA group had increased expressions of Bax, caspase-3, and AI but decreased Bcl-2 and HSP27 expressions in AS plaque, as well as larger plaque areas, the relative positive area of HSP27 and higher ROS levels in aorta when compared with those in the model group (all P < 0.05).

CONCLUSION

HSP27 exerts its protective role by suppressing ROS and AS progression by inhibiting mitochondria apoptosis pathway in CHD.

Putative consequences of exposure to Helicobacter pylori infection in patients with coronary heart disease in terms of humoral immune response and inflammation

INTRODUCTION

Pathogens, including Helicobacter pylori (Hp), have been suggested to contribute to the development of coronary heart disease (CHD), although the evidence still remains insufficient. The study was focused on the exposure of CHD patients to Hp and resulting anti-Hp heat shock protein B HspB antibody production in relation to the level of serum lipopolysaccharide binding protein (LBP) as a marker of inflammation.

MATERIAL AND METHODS

One hundred seventy CHD patients and 58 non-CHD individuals participated in this study. Coronary angiography confirmed the atheromatic background of CHD. The panel of classical risk factors included: arterial hypertension, diabetes, total cholesterol, low-density lipoprotein (LDL)/high-density lipoprotein (HDL) cholesterol, triglycerides, obesity and nicotinism. The Hp status was estimated by (13)C urea breath test and serology. Immunoblot and ELISA were used for screening the sera samples for anti-Hp HspB immunoglobulins (Igs) and LBP.

RESULTS

Coronary heart disease patients were exposed to Hp more frequently than non-CHD individuals. This was associated with increased levels of specific anti-Hp IgG2 and IgA as well as total IgA. Hp infected CHD and non-CHD donors produced anti-Hp HspB IgG cross-reacting with human Hsp 60. In CHD patients the LBP level was significantly higher in comparison to non-CHD donors. This was related to the severity of the disease. Type I Hp strains stimulated higher LBP levels than less pathogenic type II isolates.

CONCLUSIONS

Lipopolysaccharide binding protein secreted in excess together with anti-Hp HspB, cross-reacting with human Hsp60, may increase the risk of vascular pathologies in Hp-exposed CHD patients.

Cardiovascular involvement in autoimmune diseases

Autoimmune diseases (AD) represent a broad spectrum of chronic conditions that may afflict specific target organs or multiple systems with a significant burden on quality of life. These conditions have common mechanisms including genetic and epigenetics factors, gender disparity, environmental triggers, pathophysiological abnormalities, and certain subphenotypes. Atherosclerosis (AT) was once considered to be a degenerative disease that was an inevitable consequence of aging. However, research in the last three decades has shown that AT is not degenerative or inevitable. It is an autoimmune-inflammatory disease associated with infectious and inflammatory factors characterized by lipoprotein metabolism alteration that leads to immune system activation with the consequent proliferation of smooth muscle cells, narrowing arteries, and atheroma formation. Both humoral and cellular immune mechanisms have been proposed to participate in the onset and progression of AT. Several risk factors, known as classic risk factors, have been described. Interestingly, the excessive cardiovascular events observed in patients with ADs are not fully explained by these factors. Several novel risk factors contribute to the development of premature vascular damage. In this review, we discuss our current understanding of how traditional and nontraditional risk factors contribute to pathogenesis of CVD in AD.

Local and systemic cellular immunity in early renal artery atherosclerosis

BACKGROUND AND OBJECTIVES

Modern imaging techniques have increased the incidental detection of renal atherosclerotic disease (RAD). Because immune activation may hasten RAD progression, identifying cellular immune markers might provide clues to clinical activity. In this study, cellular immune markers were assessed in early RAD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Immune cell markers in peripheral blood of two groups of hypertensive patients with normal carotid and coronary arteries were evaluated: 28 patients had incidental RAD and 22 patients had normal renal arteries; 21 renal arteries obtained at necropsy from individuals with history of hypertension and tissue evidence of RAD were examined and matched with 21 individuals with normal renal arteries. Cell subpopulations were measured by flow cytometry in peripheral blood and direct cell count, respectively, using T and dendritic cells monoclonal antibodies.

RESULTS

Peripheral blood of RAD patients showed increased numbers of cells expressing CD3, CD4, CD83, and CD86. CD4 to CD8 ratio was 8.3 ± 1.4 (RAD) to 3.4 ± 0.9 (normal; P<0.001). No differences were found in CD25, CD8, and S100 among groups. Postmortem samples from RAD showed increased CD3+, CD4+, CD86+, and S100+ cells, whereas CD25+ and CD8+ were unmodified between groups. CD4+ to CD8+ ratio was higher in the RAD(PM) group.

CONCLUSIONS

These results are consistent with an increased expression of immune cell markers in early RAD. Additional studies will explore if they may potentially turn into treatment targets to prevent disease progression.

Frequency-dependent response of the vascular endothelium to pulsatile shear stress

As a result of the complex blood flow patterns that occur in the arterial tree, certain regions of the vessel wall experience fluctuations in shear stress that are dominated by harmonic frequencies higher than the heart rate ( 11 ). To assess whether variations in frequency affect endothelial gene expression, the gene expression patterns of cultured porcine aortic endothelium exposed to three sinusoidal waveforms (1, 2, and 3 Hz; amplitude = 15 dyn/cm2) and one physiological waveform were compared with the expression profiles elicited by steady flow. At each frequency, including steady flow, three levels of mean shear stress (0, 7.5, and 15 dyn/cm2) were used. After 24 h shear exposure, RNA was extracted for microarray analysis against 10,665 Sus scrofa oligonucleotides. A two-way ANOVA identified 232 genes of which their transcription was differentially modulated by frequency, while mean shear significantly affected the expression of ∼3,000 genes. One-way ANOVAs showed that the number of frequency-dependent genes increased as the mean shear stress was reduced. At 1 Hz, several inflammatory transcripts were repressed relative to steady flow, including VCAM and IL-8, whereas several atheroprotective transcripts were induced. The anti-inflammatory response at 1 Hz was reversed at 2 Hz. The proinflammatory response evoked by the higher frequency was most pronounced under reversing and oscillatory shear. This study suggests that arterial regions subject to both shear reversal and dominant frequencies that exceed the normal heart rate are at greater risk for atherosclerotic lesion development.

Inflammation — a lifelong companion

Inflammation is a key component of the immune system. It has important functions in both defense and pathophysiological events maintaining the dynamic homeostasis of a host organism including its tissues, organs and individual cells. On the cellular level it is controlled by more than 400 currently known genes. Their polymorphisms and environmental conditions give rise to different genotypes in human population. Pro-inflammatory genotype, which dominates in the present population, may be advantageous in childhood but not in elderly people because it is characterized by an increased vulnerability to, and intensity of, inflammatory reactions. These reactions may be the possible reasons of chronic inflammatory diseases, especially in old age. Better understanding of complex molecular and cellular inflammatory mechanisms is indispensable for detailed knowledge of pathogenesis of many diseases, their prevention and directed drug therapy. Here we summarize the basic current knowledge on these mechanisms.

Mortality and morbidity rates are increased in people with epilepsy: is stress part of the equation?

People with epilepsy (PWE), particularly those with more severe seizures, are at risk of premature death. The contribution of deaths unrelated to epilepsy to this risk is likely to be significant. Recent studies indicate that comorbid conditions are similarly increased in PWE. The reason for these increases in unrelated deaths and comorbid conditions is unclear. In this article, we argue that having seizures is psychologically stressful, and that this stress can lead to a whole range of pathophysiological changes that may trigger various physical illnesses. Hence, psychological stress may be a significant factor contributing to the increase in mortality and comorbidity rates in PWE. This speculation is unlikely to be proven at this stage because of the complexity of the trials required. In PWE who continue to have seizures, more needs to be done to help them cope with the stress. Additionally, attention needs to be paid to improve nutritional status and physical fitness. These steps are likely to enhance the overall health of PWE and may reduce premature mortality and comorbidity rates.