C-reactive protein down-regulates endothelial nitric oxide synthase expression and promotes apoptosis in endothelial progenitor cells through receptor for advanced glycation end-products

Mitochondrial damage and clearance in retinal pigment epithelial cells

Age-related macular degeneration (AMD) is a devastating eye disease that causes permanent vision loss in the central part of the retina, known as the macula. Patients with such severe visual loss face a reduced quality of life and are at a 1.5 times greater risk of death compared to the general population. Currently, there is no cure for or effective treatment for dry AMD. There are several mechanisms thought to underlie the disease, for example, ageing-associated chronic oxidative stress, mitochondrial damage, harmful protein aggregation and inflammation. As a way of gaining a better understanding of the molecular mechanisms behind AMD and thus developing new therapies, we have created a peroxisome proliferator-activated receptor gamma coactivator 1-alpha and nuclear factor erythroid 2-related factor 2 (PGC1α/NFE2L2) double-knockout (dKO) mouse model that mimics many of the clinical features of dry AMD, including elevated levels of oxidative stress markers, damaged mitochondria, accumulating lysosomal lipofuscin and extracellular drusen-like structures in retinal pigment epithelial cells (RPE). In addition, a human RPE cell-based model was established to examine the impact of non-functional intracellular clearance systems on inflammasome activation. In this study, we found that there was a disturbance in the autolysosomal machinery responsible for clearing mitochondria in the RPE cells of one-year-old PGC1α/NFE2L2-deficient mice. The confocal immunohistochemical analysis revealed an increase in autophagosome marker microtubule-associated proteins 1A/1B light chain 3B (LC3B) as well as multiple mitophagy markers such as PTE-induced putative kinase 1 (PINK1) and E3 ubiquitin ligase (PARKIN), along with signs of damaged mitochondria. However, no increase in autolysosome formation was detected, nor was there a colocalization of the lysosomal marker LAMP2 or the mitochondrial marker, ATP synthase β. There was an upregulation of late autolysosomal fusion Ras-related protein (Rab7) in the perinuclear space of RPE cells, together with autofluorescent aggregates. Additionally, we observed an increase in the numbers of Toll-like receptors 3 and 9, while those of NOD-like receptor 3 were decreased in PGC1α/NFE2L2 dKO retinal specimens compared to wild-type animals. There was a trend towards increased complement component C5a and increased involvement of the serine protease enzyme, thrombin, in enhancing the terminal pathway producing C5a, independent of C3. The levels of primary acute phase C-reactive protein and receptor for advanced glycation end products were also increased in the PGC1α/NFE2L2 dKO retina. Furthermore, selective proteasome inhibition with epoxomicin promoted both nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and mitochondrial-mediated oxidative stress, leading to the release of mitochondrial DNA to the cytosol, resulting in potassium efflux-dependent activation of the absent in melanoma 2 (AIM2) inflammasome and the subsequent secretion of interleukin-1β in ARPE-19 cells. In conclusion, the data suggest that there is at least a relative decrease in mitophagy, increases in the amounts of C5 and thrombin and decreased C3 levels in this dry AMD-like model. Moreover, selective proteasome inhibition evoked mitochondrial damage and AIM2 inflammasome activation in ARPE-19 cells.

Levels of circulating endothelial progenitor cells inversely correlate with manic and positive symptom severity in patients with bipolar disorder

OBJECTIVES

Patients with bipolar disorder (BPD) are at high risk of cardiovascular diseases (CVDs) that are attributed to endothelial dysfunction. Circulating endothelial progenitor cells (cEPCs) are proposed as indicators of endothelial dysfunction. This study examined the relationship of cEPC numbers with BPD diagnosis and its clinical symptoms in patients with BPD.

METHODS

We recruited 48 patients with BPD and 50 healthy controls (HCs). All the patients had scores of <13 on the Young Mania Rating Scale (YMRS). In addition to the YMRS and Clinical Global Impression for BPD (CGI-BP), bipolar patients were assessed using relevant measurements for their depression, anxiety, general psychopathology, cognitive dysfunction and deficit, somatic symptoms, quality of life, and level of disability. cEPC counts were measured using flow cytometry.

RESULTS

The numbers of immature and mature cEPCs in the bipolar patients did not significantly differ from those in the HCs. After correction for multiple comparisons and controlling for body mass index and smokers, the number of immature cEPCs was observed to be inversely correlated with CGI-BP (corrected p [p_corr ] = .00018) and positive scores in the positive and negative syndrome scale (PANSS-P; p_corr  = .0049). The number of mature cEPCs was inversely correlated with YMRS (p_corr  = .014), CGI-BP (p_corr  = .00022), and PANSS-P (p_corr  = .0049) scores. In multivariate stepwise analysis, numbers of both types of cEPCs were associated with CGI-BP.

CONCLUSIONS

cEPC levels, an indicator of endothelial dysfunction and risk of CVDs, may be associated manic and positive symptom severities in patients with BPD.

Advances of Endothelial Progenitor Cells in the Development of Depression

Depression is a major psychological disease of human beings. With the severity of depression, it elevates the risk of cardiovascular disease (CVD), especially acute coronary syndrome (ACS), resulting in serious harm to human health. The number of endothelial progenitor cells (EPCs) is closely related to the development of depression. It has been reported that the number of peripheral blood EPCs in patients with depression was reduced. However, effects on the function of EPCs in depression are still unclear. This paper aims to analyze and summarize the research of EPCs in depression, and we envision that EPCs might act as a new target for evaluating the severity of depression and its complications.

Oxidative Stress and Mitochondrial Damage in Dry Age-Related Macular Degeneration Like NFE2L2/PGC-1α -/- Mouse Model Evoke Complement Component C5a Independent of C3

Aging-associated chronic oxidative stress and inflammation are known to be involved in various diseases, e.g., age-related macular degeneration (AMD). Previously, we reported the presence of dry AMD-like signs, such as elevated oxidative stress, dysfunctional mitophagy and the accumulation of detrimental oxidized materials in the retinal pigment epithelial (RPE) cells of nuclear factor erythroid 2-related factor 2, and a peroxisome proliferator-activated receptor gamma coactivator 1-alpha (NFE2L2/PGC1α) double knockout (dKO) mouse model. Here, we investigated the dynamics of inflammatory markers in one-year-old NFE2L2/PGC1α dKO mice. Immunohistochemical analysis revealed an increase in levels of Toll-like receptors 3 and 9, while those of NOD-like receptor 3 were decreased in NFE2L2/PGC1α dKO retinal specimens as compared to wild type animals. Further analysis showed a trend towards an increase in complement component C5a independent of component C3, observed to be tightly regulated by complement factor H. Interestingly, we found that thrombin, a serine protease enzyme, was involved in enhancing the terminal pathway producing C5a, independent of C3. We also detected an increase in primary acute phase C-reactive protein and receptor for advanced glycation end products in NFE2L2/PGC1α dKO retina. Our main data show C5 and thrombin upregulation together with decreased C3 levels in this dry AMD-like model. In general, the retina strives to mount an orchestrated inflammatory response while attempting to maintain tissue homeostasis and resolve inflammation.

Physical Exercise and Cardiac Repair: The Potential Role of Nitric Oxide in Boosting Stem Cell Regenerative Biology

Over the years strong evidence has been accumulated showing that aerobic physical exercise exerts beneficial effects on the prevention and reduction of cardiovascular risk. Exercise in healthy subjects fosters physiological remodeling of the adult heart. Concurrently, physical training can significantly slow-down or even reverse the maladaptive pathologic cardiac remodeling in cardiac diseases, improving heart function. The underlying cellular and molecular mechanisms of the beneficial effects of physical exercise on the heart are still a subject of intensive study. Aerobic activity increases cardiovascular nitric oxide (NO) released mainly through nitric oxidase synthase 3 activity, promoting endothelium-dependent vasodilation, reducing vascular resistance, and lowering blood pressure. On the reverse, an imbalance between increasing free radical production and decreased NO generation characterizes pathologic remodeling, which has been termed the "nitroso-redox imbalance". Besides these classical evidence on the role of NO in cardiac physiology and pathology, accumulating data show that NO regulate different aspects of stem cell biology, including survival, proliferation, migration, differentiation, and secretion of pro-regenerative factors. Concurrently, it has been shown that physical exercise generates physiological remodeling while antagonizes pathologic remodeling also by fostering cardiac regeneration, including new cardiomyocyte formation. This review is therefore focused on the possible link between physical exercise, NO, and stem cell biology in the cardiac regenerative/reparative response to physiological or pathological load. Cellular and molecular mechanisms that generate an exercise-induced cardioprotective phenotype are discussed in regards with myocardial repair and regeneration. Aerobic training can benefit cells implicated in cardiovascular homeostasis and response to damage by NO-mediated pathways that protect stem cells in the hostile environment, enhance their activation and differentiation and, in turn, translate to more efficient myocardial tissue regeneration. Moreover, stem cell preconditioning by and/or local potentiation of NO signaling can be envisioned as promising approaches to improve the post-transplantation stem cell survival and the efficacy of cardiac stem cell therapy.

Mangiferin alleviates hypertension induced by hyperuricemia via increasing nitric oxide releases

Mangiferin, a natural glucosyl xanthone, was confirmed to be an effective uric acid (UA)- lowering agent with dual action of inhibiting production and promoting excretion of UA. In this study, we aimed to evaluate the effect of mangiferin on alleviating hypertension induced by hyperuricemia. Mangiferin (30, 60, 120 mg/kg) was administered intragastrically to hyperuricemic rats induced by gavage with potassium oxonate (750 mg/kg). Systolic blood pressure (SBP), serum levels of UA, nitric oxide (NO), C-reactionprotein (CRP) and ONOO^- were measured. The mRNA and protein levels of endothelial nitric oxide synthase (eNOS), intercellular adhesion molecule-1 (ICAM-1), CRP were also analyzed. Human umbilical vein endothelial cells (HUVECs) were used in vitro studies. Administration of mangiferin significantly decreased the serum urate level and SBP at 8 weeks and last to 12 weeks. Further more, mangiferin could increase the release of NO and decrease the level of CRP in blood. In addition, mangiferin reversed the protein expression of eNOS, CRP, ICAM-1 and ONOO^- in aortic segments in hyperuricemic rats. The results in vitro were consistent with the observed results in vivo. Taken together, these data suggested that mangiferin has played an important part in alleviating hypertension induced by hyperuricemia via increasing NO secretion and improving endothelial function.

Scorpion Venom Active Polypeptide May Be a New External Drug of Diabetic Ulcer

Background

The epidermal growth factor (EGF) is recognized medicine of therapy in ulcer. However, its efficacy has been challenged. We compared scorpion venom active polypeptide and EGF of therapeutic effects in diabetic ulcer.

Methods

The scorpion venom active polypeptide is made into gel. Fourteen diabetic SD rats were randomly divided into scorpion peptide gel group (SPG group) and EGF group. Before treatment, the rat model of diabetic ulcer was created. The levels of IL-1, IL-6, IL-8, and TNF-α in the wound tissue were measured at different time points during the treatment, secretions of wound were collected for bacterial culture, and the wound healing was recorded.

Results

Wound healing was faster in SPG group compared to EGF group (3 weeks versus 5 weeks, t-test, p = 0.032). The levels of IL-1, IL-6, IL-8, and TNF-α were not statistically different when the wounds were formed but showed significant differences from the 2nd to the 5th week between two groups. The infection rate was higher in the EGF group (42.86% versus 0, Chi-square test, p = 0.025).

Conclusions

Scorpion venom active polypeptide shortens wound healing with a stronger anti-inflammation and antibacterial effect and may be a new and effective topical drug for the treatment of diabetic ulcers.

IFN-α Negatively Regulates the Expression of Endothelial Nitric Oxide Synthase and Nitric Oxide Production: Implications for Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a known risk factor for endothelial dysfunction. Murine and human lupus studies revealed a role for IFN-α in vascular abnormalities associated with impaired blood vessel dilation. However, the impact of IFN-α on mediators that induce vasodilation and modulate inflammation, including endothelial NO synthase (eNOS) and NO bioavailability, are unknown. The objectives of this study were to determine how IFN-α promotes endothelial dysfunction in SLE, focusing on its regulation of eNOS and NO production in endothelial cells. We demonstrate that IFN-α promotes an endothelial dysfunction signature in HUVECs that is characterized by transcription suppression and mRNA instability of eNOS complemented by upregulation of MCP1 and VCAM1 These changes are associated with IFN-inducible gene expression. IFN-α impairs insulin-mediated NO production, and altered gene expression resulted from eNOS instability, possibly due to enhanced miR-155 expression. IFN-α significantly impaired NO production in insulin-stimulated HUVECs. IFN-α treatment also led to enhanced neutrophil adhesion. Our study introduces a novel pathway by which IFN-α serves as a proatherogenic mediator through repression of eNOS-dependent pathways. This could promote the development of endothelial dysfunction and cardiovascular disease in SLE.

Effect of Intensive Periodontal Therapy on Blood Pressure and Endothelial Microparticles in Patients With Prehypertension and Periodontitis: A Randomized Controlled Trial

BACKGROUND

Although some studies show a positive association between periodontitis and blood pressure (BP) elevation, research on the effect of intensive periodontal treatment on decline in BP levels and endothelial microparticles (EMPs) without any antihypertensive management is lacking. Therefore, the present clinical trial explores whether intensive periodontal therapy would lower BP levels and EMPs of patients with prehypertension with periodontitis.

METHODS

From a total 107 patients, 95 underwent randomization (47 assigned to control-treatment [CT] group and 48 assigned to intensive-treatment [IT] group) and completed the trial. Patients received intervention for 4 consecutive weeks and were followed for 6 months. Levels of BP and EMPs were evaluated at baseline and 1, 3, and 6 months after intervention.

RESULTS

Periodontal conditions were significantly improved (P <0.05) 6 months after intensive periodontal treatment. In parallel, the primary outcomes including systolic and diastolic BP and EMPs were markedly reduced in the IT group compared with the CT group (absolute difference: 12.57 and 9.65 mm Hg and 581.59/μL, respectively; 95% confidence intervals: 10.45 to 14.69, 7.06 to 12.24, and 348.12 to 815.06, respectively; P <0.05). Reduction in BP levels and EMPs was related to improvement in probing depth (r = 0.358, 0.363, and 0.676, respectively, by the Pearson product-moment correlation; P = 0.009, 0.008, and P <0.001, respectively).

CONCLUSION

To the best knowledge of the authors, the present study demonstrates for the first time that intensive periodontal intervention without any antihypertensive medication therapy may be an effective means to lower levels of BP and EMPs in patients with prehypertension with periodontitis.

Observational and mechanistic links between C-reactive protein and blood pressure in elderly women

It is hypothesized that chronic systemic inflammation contributes to the age-related decline in cardiovascular function. The aim of the present study was to combine an assessment of the relationship between the serum level of C-reactive protein (CRP) and systolic and diastolic blood pressure in 108 elderly women (65 and 70 years) with an in-vitro exploration of the effects of CRP on the proliferative and angiogenic potential of endothelial cells exposed to serum in elderly women. Based on the median CRP level in our population, LowCRP (CRP<1.3mg/L) and HighCRP (>1.3mg/L) groups were identified. Body mass index, waist circumference, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly higher in the HighCRP group than in the LowCRP group (p<0.05). The influence of CRP on SBP and DBP remained significant after adjustments for BMI and use of antihypertensive medication (p<0.05). When adjusting for waist circumference the observed influence of CRP on SPB was attenuated (p=0.062). We next evaluated the ability to form capillary tubes (angiogenesis assay) and the proliferation rate of endothelial cells exposed to the sera of elderly women. Increased serum CRP levels were associated with an increased doubling time of endothelial cells (R(2)=0.39; p<0.05) and decreased capillary tube length (R(2)=0.30; p<0.05), indicating a reduction in the proliferation rate of endothelial cells and angiogenic potential. In conclusion, chronic inflammation influences blood pressure in elderly women and compromises endothelial cell function, thus contributing to the age-related decline in vascular health.

BM ageing: Implication for cell therapy with EPCs

The bone marrow (BM) is a well-recognized source of stem/progenitor cells for cell therapy in cardiovascular diseases (CVDs). Preclinical and clinical studies suggest that endothelial progenitor cells (EPCs) contribute to reparative process of vascular endothelium and participate in angiogenesis. As for all organs and cells across the lifespan, BM and EPCs are negatively impacted by ageing due to microenvironment modifications and EPC progressive dysfunctions. The encouraging results in terms of neovascularization observed in young animals after EPC administration were mitigated in aged patients treated for ischemic CVDs. The limited efficacy of EPC-based therapy in clinical setting might be ascribed at least partly to ageing. In this review, we comprehensively discussed the age-related changes of BM and EPCs and their implication for cardiovascular cell-therapies. Finally, we examined alternative approaches under investigation to enhance EPC potency.

Insights into the molecular mechanisms of diabetes-induced endothelial dysfunction: focus on oxidative stress and endothelial progenitor cells

Diabetes mellitus is a heterogeneous, multifactorial, chronic disease characterized by hyperglycemia owing to insulin insufficiency and insulin resistance (IR). Recent epidemiological studies showed that the diabetes epidemic affects 382 million people worldwide in 2013, and this figure is expected to be 600 million people by 2035. Diabetes is associated with microvascular and macrovascular complications resulting in accelerated endothelial dysfunction (ED), atherosclerosis, and cardiovascular disease (CVD). Unfortunately, the complex pathophysiology of diabetic cardiovascular damage is not fully understood. Therefore, there is a clear need to better understand the molecular pathophysiology of ED in diabetes, and consequently, better treatment options and novel efficacious therapies could be identified. In the light of recent extensive research, we re-investigate the association between diabetes-associated metabolic disturbances (IR, subclinical inflammation, dyslipidemia, hyperglycemia, dysregulated production of adipokines, defective incretin and gut hormones production/action, and oxidative stress) and ED, focusing on oxidative stress and endothelial progenitor cells (EPCs). In addition, we re-emphasize that oxidative stress is the final common pathway that transduces signals from other conditions-either directly or indirectly-leading to ED and CVD.

Investigation of phosphoproteome in RAGE signaling

The receptor for advanced glycation end products (RAGE) is one of the most important proteins implicated in diabetes, cardiovascular diseases, neurodegenerative diseases, and cancer. It is a pattern recognition receptor by virtue of its ability to interact with multiple ligands, RAGE activates several signal transduction pathways through involvement of various kinases that phosphorylate their respective substrates. Only few substrates have been known to be phosphorylated in response to activation by RAGE (e.g., nuclear factor kappa B); however, it is possible that these kinases can phosphorylate multiple substrates depending upon their expression and localization, leading to altered cellular responses in different cell types and conditions. One such example is, glycogen synthase kinase 3 beta which is known to phosphorylate glycogen synthase, acts downstream to RAGE, and hyperphosphorylates microtubule-associated protein tau causing neuronal damage. Thus, it is important to understand the role of various RAGE-activated kinases and their substrates. Therefore, we have reviewed here the details of RAGE-activated kinases in response to different ligands and their respective phosphoproteome. Furthermore, we discuss the analysis of the data mined for known substrates of these kinases from the PhosphoSitePlus (http://www.phosphosite.org) database, and the role of some of the important substrates involved in cancer, diabetes, cardiovascular diseases, and neurodegenerative diseases. In summary, this review provides information on RAGE-activated kinases and their phosphoproteome, which will be helpful in understanding the possible role of RAGE and its ligands in progression of diseases.

Impact of prior chronic statin therapy and high-intensity statin therapy at discharge on circulating endothelial progenitor cell levels in patients with acute myocardial infarction: a prospective observational study

BACKGROUND

Endothelial progenitor stem cells (EPCs) are mobilized to the peripheral circulation in response to myocardial ischemia, playing a crucial role in vascular repair. Statins have been shown to stimulate EPCs. However, neither the impact of previous statin therapy on EPC response of acute myocardial infarction (AMI) patients nor the effect of post-AMI high-intensity statin therapy on the evolution of circulating EPC levels has yet been addressed. Therefore, we aimed to compare circulating EPC levels between patients receiving long-term statin therapy before the AMI and statin-naive patients and to assess the impact of high-intensity statin therapy at discharge on the evolution of circulating EPCs post-AMI.

METHODS

This is a prospective observational study of 100 AMI patients. Circulating EPCs (CD45dimCD34 + KDR + cells) and their subpopulation coexpressing the homing marker CXCR4 were quantified by the high-performance flow cytometer FACSCanto II in whole blood, in two different moments: within the first 24 h of admission and 3 months post-AMI. Patients were followed up clinically for 2 years.

RESULTS

Patients previously treated with statins had significantly higher levels of EPCs coexpressing CXCR4 (1.9 ± 1.4 vs. 1.3 ± 1.0 cells/1,000,000 events, p = 0.031) than statin-naive patients. In addition, the subanalysis of diabetics (N = 38) also revealed that patients previously on statins had significantly greater numbers of both CD45dimCD34 + KDR + CXCR4+ cells (p = 0.024) and CD45dimCD34 + KDR + CD133+ cells (p = 0.022) than statin-naive patients. Regarding the evolution of EPC levels after the AMI, patients not on a high-intensity statin therapy at discharge had a significant reduction of CD45dimCD34 + KDR + and CD45dimCD34 + KDR + CXCR4+ cells from baseline to 3 months follow-up (p = 0.031 and p = 0.005, respectively). However, patients discharged on a high-intensity statin therapy maintained circulating levels of all EPC populations, presenting at 3 months of follow-up significantly higher EPC levels than patients not on an intensive statin therapy. Moreover, the high-intensity statin treatment group had significantly better clinical outcomes during the 2-year follow-up period than patients not discharged on a high-intensity statin therapy.

CONCLUSION

Chronic statin therapy prior to an AMI strongly enhances the response of EPCs to myocardial ischemia, even in diabetic patients. Furthermore, high-intensity statin therapy after an AMI prevents the expected decrease of circulating EPC levels during follow-up. These results reinforce the importance of an early and intensive statin therapy in AMI patients.

A modified portfolio diet complements medical management to reduce cardiovascular risk factors in diabetic patients with coronary artery disease

BACKGROUND & AIMS

Secondary prevention can improve outcomes in high risk patients. This study investigated the magnitude of cardiovascular risk reduction associated with consumption of a modified portfolio diet in parallel with medical management.

DESIGN

30 patients with type II diabetes, 6 weeks post bypass surgery received dietary counseling on a Modified Portfolio Diet (MPD) (low fat, 8 g/1000 kcal viscous fibres, 17 g/1000 kcal soy protein and 22 g/1000 kcal almonds). Lipid profiles, endothelial function and markers of glycemic control, oxidative stress and inflammation were measured at baseline and following two and four weeks of intervention. Seven patients with no diet therapy served as time controls.

RESULTS

Consumption of the MPD resulted in a 19% relative reduction in LDL (1.9 ± 0.8 vs 1.6 ± 0.6 mmol/L, p < 0.001) with no change in HDL cholesterol. Homocysteine levels dropped significantly (10.1 ± 2.7 vs 7.9 ± 4 μmol/L, p = 0.006) over the study period. Flow mediated dilatation increased significantly in treated patients (3.8 ± 3.8% to 6.5 ± 3.6%, p = 0.004) while remaining constant in controls (p = 0.6). Endothelial progenitor cells numbers (CD34+, CD 133+ and UEA-1+) increased significantly following MPD consumption (p < 0.02) with no difference in migratory capacity. In contrast, time controls showed no significant changes.

CONCLUSION

Dietary intervention in medically managed, high risk patients resulted in important reductions in risk factors. Clinical Trials registry number NCT00462436.

Effects of simvastatin/ezetimibe on microparticles, endothelial progenitor cells and platelet aggregation in subjects with coronary heart disease under antiplatelet therapy

It is not known whether the addition of ezetimibe to statins adds cardiovascular protection beyond the expected changes in lipid levels. Subjects with coronary heart disease were treated with four consecutive 1-week courses of therapy (T) and evaluations. The courses were: T1, 100 mg aspirin alone; T2, 100 mg aspirin and 40 mg simvastatin/10 mg ezetimibe; T3, 40 mg simvastatin/10 mg ezetimibe, and 75 mg clopidogrel (300 mg initial loading dose); T4, 75 mg clopidogrel alone. Platelet aggregation was examined in whole blood. Endothelial microparticles (CD51), platelet microparticles (CD42/CD31), and endothelial progenitor cells (CD34/CD133; CDKDR/CD133, or CD34/KDR) were quantified by flow cytometry. Endothelial function was examined by flow-mediated dilation. Comparisons between therapies revealed differences in lipids (T2 and T3<T1 and T4 for total cholesterol, LDL-C, and triglycerides; P<0.002 for all), as well as for endothelial function (T2>T1 and T4, P=0.001). Decreased platelet aggregation was observed after aspirin (arachidonic acid, T1<T3 and T4, P=0.034) and clopidogrel (adenosine, T3 and T4<T1 and T2, P<0.0001) therapy. Simvastatin/ezetimibe diphosphate did not change platelet aggregation, the amount of circulating endothelial and platelet microparticles, or endothelial progenitor cells. Cardiovascular protection following therapy with simvastatin/ezetimibe seems restricted to lipid changes and improvement of endothelial function not affecting the release of microparticles, mobilization of endothelial progenitor cells or decreased platelet aggregation.

Activity of daily living is associated with circulating CD34+/KDR+ cells and granulocyte colony-stimulating factor levels in patients after myocardial infarction

The study aimed to investigate whether the extent of activities of daily living (ADL) of patients after myocardial infarction affect numbers of circulating CD34+/KDR+ and CD45+/CD34+ cells, which are supposed to protect structural and functional endothelial integrity. In a cross-sectional study, 34 male coronary artery disease patients with a history of myocardial infarction were assessed for times spent per week for specific physical ADL, including basic activities (instrumental ADL), leisure time activities, and sport activities, using a validated questionnaire. Individual specific activity times were multiplied with respective specific metabolic equivalent scores to obtain levels of specific activities. Numbers of circulating CD34+/KDR+ and CD45+/CD34+ cells were analyzed by flow cytometry. Furthermore, the colony-forming capacity of CD34+ cells and the level of granulocyte colony-stimulating factor (G-CSF) in serum were measured. Analysis revealed that the extent of total activities and basic activities, as well as total activity time, were positively correlated with numbers of circulating CD34+/KDR+ cells ( r = 0.60, 0.56, and 0.55, P < 0.05). Higher levels of total activity were also associated with increased colony-forming capacity of CD34+ cells ( r = 0.54, P < 0.05) and with higher systemic levels of G-CSF ( r = 0.44, P < 0.05). These findings indicate that even ADL-related activities of coronary artery disease patients after myocardial infarction exert stimulating effects on CD34+/KDR+ cell mobilization, potentially mediated by increased G-CSF levels. This, in turn, potentially contributes to the beneficial effects of exercise on the diseased cardiovascular system.

C-reactive protein promotes acute kidney injury by impairing G1/S-dependent tubular epithelium cell regeneration

There are three new and significant findings from the present study: (i) CRP is not only a biomarker for, but also a pathogenic mediator in, AKI; (ii) CRP promotes AKI by inhibiting G1/S-dependent TEC regeneration; and (iii) blockade of CRP signalling attenuates AKI.

Interpretation of C-reactive protein concentrations in critically ill patients

Infection is often difficult to recognize in critically ill patients because of the marked coexisting inflammatory process. Lack of early recognition prevents timely resuscitation and effective antimicrobial therapy, resulting in increased morbidity and mortality. Measurement of a biomarker, such as C-reactive protein (CRP) concentration, in addition to history and physical signs, could facilitate diagnosis. Although frequently measured in clinical practice, few studies have reported on the pathophysiological role of this biomarker and its predictive value in critically ill patients. In this review, we discuss the pathophysiological role of CRP and its potential interpretation in the inflammatory processes observed in critically ill patients.

Statins modulate feedback regulation mechanisms between advanced glycation end-products and C-reactive protein: evidence in patients with acute myocardial infarction

OBJECTIVE

High sensitivity C-reactive protein (hsCRP) and advanced glycation end-products (AGEs) have been proposed as mediators in inflammation and atherosclerosis. Therefore, we studied the relation between AGE and hsCRP in patients with acute myocardial infarction (AMI).

METHODS

Patients with AMI diagnosis and satisfying our inclusion criteria were included during 2009-2011 in an unicentre registry of AMI patients for a cross-sectional study. The final cohort was composed of 156 patients (46.2% STEMI and 27.6% with type-2 diabetes). AGE and hsCRP were measured in plasma.

RESULTS

Diabetic patients were older than non-diabetics (68.6 ± 10.6 vs. 60.4 ± 13.9 years; p<0.05), presented more incidence of hypertension (62.8 vs. 36.3%; p<0.05) and were in a higher Killip class (p<0.05). The mean values of fluorescent AGE and hsCRP levels were 61.3 ± 49.8 AU and 2.4 ± 4.0 mg/L, respectively, and there were no differences in these parameters between diabetic and non-diabetic patients. A direct association between AGE and hsCRP levels was observed, mainly in diabetic patients (r=0.258; p=0.018). Importantly, this association disappeared in patients who had been treated with statins before their AMI (r=-0.055; p=0.845), but it was maintained in non-diabetic patients naïve for statins treatment (r=0.634; p<0.001), independently of other treatments and confounding parameters.

CONCLUSIONS

This is the first evidence in humans of a feedback regulation mechanism between CRP and the AGE-RAGE axis modulated by statins.

Effects of ACE inhibition on endothelial progenitor cell mobilization and prognosis after acute myocardial infarction in type 2 diabetic patients

OBJECTIVE

We aimed to assess the chemotactic response of endothelial progenitor cells to angiotensin-converting enzyme inhibitors in T2DM patients after acute myocardial infarction, as well as the associated prognosis.

METHODS

Sixty-eight T2DM patients with acute myocardial infarction were randomized to either receive or not receive daily oral perindopril 4 mg, and 36 non-diabetic patients with acute myocardial infarction were enrolled as controls. The numbers of circulating CD45-/low+CD34+CD133+KDR+ endothelial progenitor cells, as well as the stromal cell-derived factor-α and high-sensitivity C reactive protein levels, were measured before acute percutaneous coronary intervention and on days 1, 3, 5, 7, 14, and 28 after percutaneous coronary intervention. Patients were followed up for 6 months. Chinese Clinical Trial Registry: ChiCTR-TRC-12002599.

RESULTS

T2DM patients had lower circulating endothelial progenitor cell counts, decreased plasma vascular endothelial growth factor and α levels, and higher plasma high-sensitivity C reactive protein levels compared with non-diabetic controls. After receiving perindopril, the number of circulating endothelial progenitor cells increased from day 3 to 7, as did the plasma levels of vascular endothelial growth factor and stromal cell-derived factor-α, compared with the levels in T2DM controls. Plasma high-sensitivity C reactive protein levels in the treated group decreased to the same levels as those in non-diabetic controls. Furthermore, compared with T2DM controls, the perindopril-treated T2DM patients had lower cardiovascular mortality and occurrence of heart failure symptoms (p<0.05) and better left ventricle function (p<0.01).

CONCLUSIONS

The use of angiotensin-converting enzyme inhibitors represents a novel approach for improving cardiovascular repair after acute myocardial infarction in T2DM patients.

The biological role of inflammation in atherosclerosis

The concept of the involvement of inflammation in the pathogenesis of atherosclerosis has existed since the 1800s, stemming from sentinel pathologic observations made by Rudolf Virchow, Karl Rokitansky, and others. Our understanding of the complex role played by immune and inflammatory mediators in the initiation and progression of atherosclerosis has evolved considerably in the intervening years, and today, a dramatically evolved understanding of these processes has led to advances in both diagnostic and prognostic approaches, as well as novel treatment modalities targeting inflammatory and immune mediators. Therapeutic interventions working through multiple mechanisms involved in atheroma pathogenesis, such as statins, which both lower lipids and alter the inflammatory milieu in the vessel wall, hold promise for the future. In this brief review, we explore the biological role of inflammation in atherosclerosis, with a focus on cellular involvement in both acute and chronic inflammation, and outline novel biomarkers of inflammation and atherosclerosis with a particular focus on the potential application of these novel approaches in improving strategies for disease diagnosis and management.

RAGE and tobacco smoke: insights into modeling chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a progressive condition characterized by chronic airway inflammation and airspace remodeling, leading to airflow limitation that is not completely reversible. Smoking is the leading risk factor for compromised lung function stemming from COPD pathogenesis. First- and second-hand cigarette smoke contain thousands of constituents, including several carcinogens and cytotoxic chemicals that orchestrate chronic lung inflammation and destructive alveolar remodeling. Receptors for advanced glycation end-products (RAGE) are multi-ligand cell surface receptors primarily expressed by diverse lung cells. RAGE expression increases following cigarette smoke exposure and expression is elevated in the lungs of patients with COPD. RAGE is responsible in part for inducing pro-inflammatory signaling pathways that culminate in expression and secretion of several cytokines, chemokines, enzymes, and other mediators. In the current review, new transgenic mouse models that conditionally over-express RAGE in pulmonary epithelium are discussed. When RAGE is over-expressed throughout embryogenesis, apoptosis in the peripheral lung causes severe lung hypoplasia. Interestingly, apoptosis in RAGE transgenic mice occurs via conserved apoptotic pathways also known to function in advanced stages of COPD. RAGE over-expression in the adult lung models features of COPD including pronounced inflammation and loss of parenchymal tissue. Understanding the biological contributions of RAGE during cigarette smoke-induced inflammation may provide critically important insight into the pathology of COPD.

Value and level of circulating endothelial progenitor cells, angiogenesis factors and mononuclear cell apoptosis in patients with chronic kidney disease

BACKGROUND

Chronic renal failure on dialysis can reduce the number of circulating endothelial progenitor cells (EPCs), but this biomarker has not been fully investigated in patients with chronic kidney disease (CKD). A link between CKD and increased mononuclear cell apoptosis (MCA) in circulation has been reported but the effect of vascular endothelial growth factor (VEGF) and stromal cell-derived factor (SDF)-1α, two angiogenesis factors, on circulating EPC levels in CKD has not been clarified. This study examined the relationships between the numbers of circulating EPCs and the severity of CKD, degree of MCA and serum levels of VEGF and SDF-1α in CKD patients.

METHODS

The numbers of circulating EPCs (CD31/CD34+, CD62E/CD34+, KDR/CD34+, CXCR4/CD34+) were measured in 166 patients with varying degrees of CKD under regular treatment at an outpatient department and in 30 volunteer control subjects.

RESULTS

CKD patients had significantly lower numbers of EPCs (p < 0.007), higher MCA in circulation and higher serum levels of VEGF and SDF-1 compared with the control subjects (all p < 0.001). Compared with patients with early CKD (stages I-III), patients with late CKD [stage IV-V or end-stage renal disease (ESRD)] had significantly lower numbers of EPCs (CXCR4/CD34+), higher MCA, and elevated serum levels of VEGF and SDF-1α (all p < 0.01). Serum VEGF level but not MCA or SDF-1α was strongly correlated with increased numbers of circulating EPCs. Multivariate analysis showed that ESRD along with lower serum albumin was independently predictive of lower numbers of circulating EPCs (p < 0.04).

CONCLUSION

Circulating EPCs were markedly reduced in CKD patients. ESRD was strongly and independently predictive of decreased numbers of circulating EPCs.

The diverse ligand repertoire of the receptor for advanced glycation endproducts and pathways to the complications of diabetes

The multi-ligand receptor RAGE was discovered on account of its ability to bind and transduce the cell stress-provoking signals of advanced glycation endproducts (AGEs). The finding that RAGE also bound pro-inflammatory molecules set the stage for linking RAGE and inflammation to the pathogenesis of diabetic macro- and microvascular complications. In this review, we focus on the roles of RAGE and its ligands in diabetes complications. We recount the findings from mice, rats, swine and human subjects suggesting that RAGE action potently contributes to vascular, inflammatory and end-organ stress and damage in types 1 and 2 diabetes. We detail the efforts to track ligands and RAGE in human subjects with diabetes to address if this axis may be a biomarker reflective of the state of the diabetic complications. Lastly, we suggest specific strategies to tackle AGE-ligand-RAGE interactions as potential therapeutic targets for diabetes and its complications.

Effect of L-arginine supplement on liver regeneration after partial hepatectomy in rats

Background

Nitric oxide (NO) has been reported to be a key mediator in hepatocyte proliferation during liver regeneration. NO is the oxidative metabolite of L-arginine, and is produced by a family of enzymes, collective termed nitric oxide synthase (NOS). Thus, administration of L-arginine might enhance liver regeneration after a hepatectomy. Another amino acid, L-glutamine, which plays an important role in catabolic states and is a crucial factor in various cellular and organ functions, is widely known to enhance liver regeneration experimentally. Thus, the present study was undertaken to evaluate the effects of an L-arginine supplement on liver regeneration, and to compared this with supplementation with L-glutamine and L-alanine (the latter as a negative control), using a rat partial hepatectomy model.

Methods

Before and after a 70% hepatectomy, rats received one of three amino acid solutions (L-arginine, L-glutamine, or L-alanine). The effects on liver regeneration of the administered solutions were examined by assessment of restituted liver mass, staining for proliferating cell nuclear antigen (PCNA), and total RNA and DNA content 24 and 72 hours after the operation.

Results

At 72 hours after the hepatectomy, the restituted liver mass, the PCNA labeling index and the DNA quantity were all significantly higher in the L-arginine and L-glutamine groups than in the control. There were no significant differences in those parameters between the L-arginine and L-glutamine groups, nor were any significant differences found between the L-alanine group and the control.

Conclusion

Oral supplements of L-arginine and L-glutamine enhanced liver regeneration after hepatectomy in rats, suggesting that an oral arginine supplement can clinically improve recovery after a major liver resection.