Negative association between circulating total homocysteine and proinflammatory chemokines MCP-1 and RANTES in prepubertal lean, but not in obese, children

Systemic Inflammation, Oxidative Stress and Cardiovascular Health in Children and Adolescents: A Systematic Review

Recent studies indicate that cerebrovascular diseases and processes of atherosclerosis originate in the childhood era and are largely influenced by chronic inflammation. Some features of vascular dysfunction in adulthood may even be programmed prenatally via genetic influences and an unfavorable intrauterine milieu. Oxidative stress, defined by an imbalance between the production and generation of reactive oxygen species (ROS) in cells and tissues and the capability of an organism to scavenge these molecules via antioxidant mechanisms, has been linked to adverse cardiovascular health in adults, yet has not been systematically reviewed in the pediatric population. We performed a systematic search as per the PRISMA guidelines in PubMed/Medline and Cochrane Reviews and detected, in total, 1228 potentially eligible pediatric articles on systemic inflammation, oxidative stress, antioxidant use, cardiovascular disease and endothelial dysfunction. The abstracts and full-text manuscripts of these were screened for inclusion and exclusion criteria, and a total of 160 articles were included. The results indicate that systemic inflammation and oxidative stress influence cardiovascular health in many chronic pediatric conditions, including hypertension, obesity, diabetes mellitus types 1 and 2, chronic kidney disease, hyperlipidemia and obstructive sleep apnea. Exercise and diet may diminish ROS formation and enhance the total serum antioxidant capacity. Antioxidant supplementation may, in selected conditions, contribute to the diminution of the oxidative state and improve endothelial function; yet, in many areas, studies provide unsatisfactory results.

Neuroendocrine Inflammatory Responses in Overweight/Obese Infants

Childhood obesity is related to a cascade of neuroendocrine inflammatory changes. However, there remains a gap in the current literature regarding the possible occurrence of these changes in overweight/obese infants. The objective of this study was to evaluate adipokines, cortisol, brain-derived neurotrophic factor (BDNF) and redox status in overweight/obese infants versus normal-weight peers. A cross-sectional study was conducted with 50 infants (25 in the overweight/obese group and 25 in the normal-weight group) between 6 and 24 months. Plasma levels of leptin, adiponectin, resistin, soluble tumor necrosis factor (TNF) receptors, chemokines, BDNF, serum cortisol and redox status were measured. Unpaired Student's t-test was used to analyze the results and a probability of p<0.05 was acceptable for rejection of the null hypothesis. The Pearson correlation was used to verify the association between the biomarkers analyzed in each group. Plasma levels of leptin (p = 0.0001), adiponectin (p = 0.0007) and BDNF (p = 0.003), and serum cortisol (p = 0.048) were significantly higher in overweight/obese infants than normal-weight infants. In contrast, the concentration of thiobarbituric acid reactive substances (TBARS) (p = 0.004), and catalase (p = 0.045) and superoxide dismutase activity (p = 0.02) were lower in overweight/obese infants than normal-weight peers. All the results together indicate neuroendocrine inflammatory response changes in overweight/obese infants between 6 and 24 months. Although there is already an environment that predisposes for a subsequent pro-inflammatory response, neuroendocrine secretion changes that permit the control of the inflammatory process in this age interval can be observed.

Relation Between Circulating Inflammatory Chemokines and Vascular Characteristics in Healthy, Young Children

BACKGROUND

Atherosclerosis begins in childhood with the occurrence of inflammatory vascular wall alterations that are detectable with B-mode ultrasound. Chemokines appear to be involved in the development of these alterations given that they occur early in the atherosclerotic pathway as mediators of vascular inflammation. However, this has not extensively been investigated. Therefore, we studied in healthy young children whether chemokines monocyte chemotactic protein 1 (MCP-1), regulated on activation normal T-cell expressed and secreted (RANTES), and vascular and intercellular adhesion molecules (VCAM and ICAM) related to vascular characteristics of the carotid artery.

METHODS AND RESULTS

We obtained demography, anthropometry, and overnight fasting plasma of 139 eight-year-old children of the Wheezing Illnesses Study Leidsche Rijn birth cohort. Carotid intima-media thickness (CIMT), distensibility, and Young's Elastic Modulus (YEM) of the common carotid artery were measured sonographically. Chemokine plasma levels were assessed using a multiplex assay. We studied the relation between the chemokines and vascular characteristics using multivariable linear regression analyses with adjustments for sex, systolic blood pressure, homeostasis model assessment of insulin resistance, triglycerides, low-density lipoprotein- and high-density lipoprotein-cholesterol. Of the studied chemokines, RANTES related to common carotid distensibility and YEM. One standard deviation increase in RANTES level related to a 5.45-MPA(-1) (95% confidence interval [CI], -9.43, -1.39; P=0.01) decrease in distensibility and to a 5.55-kPa increase in YEM (95% CI, 0.40, 10.85; P=0.03). RANTES did not relate to CIMT. MCP-1, VCAM, and ICAM did not relate to any of the studied vascular characteristics.

CONCLUSION

RANTES appears to be involved in the development of preatherosclerotic inflammatory vascular alterations already in healthy, young children. This may provide further insight into the early-life origins of atherosclerosis.

Effect of folic acid supplementation on levels of circulating Monocyte Chemoattractant Protein-1 and the presence of intravascular ultrasound derived virtual histology thin-cap fibroatheromas in patients with stable angina pectoris

BACKGROUND

Virtual Histology Intravascular Ultrasound (VH-IVUS) may be used to detect early signs of unstable coronary artery disease. Monocyte Chemoattractant Protein-1 (MCP-1) is linked with coronary atherosclerosis and plaque instability and could potentially be modified by folic acid treatment.

METHODS

In a randomized, prospective study, 102 patients with stable angina pectoris (SAP) received percutaneous coronary intervention and established medical treatment as well as either homocysteine-lowering folic acid/vitamin B12 (± B6) or placebo (± B6) for 1 year before VH-IVUS was performed. The presence of VH-Thin-Cap Fibroatheroma (VH-TCFA) in non-intervened coronary vessels was registered and serum levels of MCP-1 were measured. The patients were subsequently followed for incident myocardial infarction (MI).

RESULTS

Patients treated with folic acid/vitamin B12 had a geometric mean (SD) MCP-1 level of 79.95 (1.49) versus 86.00 (1.43) pg/mL for patients receiving placebo (p-value 0.34). VH-TCFA lesions were present in 7.8% of patients and did not differ between intervention arms (p-value 0.47). Serum levels of MCP-1 were 1.46 (95% CI 1.12 to 1.92) times higher in patients with VH-TCFA lesions than in those without (p-value 0.005). Afterwards, patients were followed for median 2.1 years and 3.8% experienced a myocardial infarction (MI), which in post-hoc Cox regression analyses was independently predicted by both MCP-1 (P-value 0.006) and VH-TCFA (p-value 0.01).

CONCLUSIONS

In patients with SAP receiving established medical treatment, folic acid supplementation is not associated with either presence of VH-TCFA or levels of MCP-1. MCP-1 is however associated with VH-TCFA, a finding corroborated by increased risk for future MI. ClinicalTrials.gov Identifier: NCT00354081.

Low-grade systemic inflammation profile, unrelated to homocysteinemia, in obese children

To investigate in prepubertal obese children (POC) the profile of chronic low-grade systemic inflammation (CLGSI) and its relation to homocysteinemia, 72 POC were evaluated for serum C-reactive protein (CRP) and amyloid A (SAA) levels, both markers of CLGSI, and plasma levels of total homocysteine (tHcy), an independent risk factor for adult atherosclerosis, in comparison to 42 prepubertal lean children (PLC). The main observations in POC were higher CRP levels compared to PLC, positive association of SAA levels to CRP levels, no association of CRP or SAA levels to tHcy levels. Thus, in POC, positively interrelated to each other, elevated CRP and unaltered SAA levels reveal a unique profile of the CLGSI, not explaining homocysteinemia-induced risk for future atherosclerosis.

Circulating chemoattractants RANTES, negatively related to endogenous androgens, and MCP-1 are differentially suppressed by hormone therapy and raloxifene

BACKGROUND

The cardinal role of chronic inflammation in the development of atherosclerosis is increasingly being recognized. Estrogens may prevent the evolution of atherosclerosis by suppressing immune response. Furthermore, the conflicting reports on the cardiovascular effects of hormone therapy between observational and clinical trials have triggered interest on the effect of alternative therapies on the cardiovascular system.

OBJECTIVE

The aim of this study was to assess the effect of estrogen, estrogen-progestin, tibolone and raloxifene therapy on circulating markers of chemotaxis in healthy postmenopausal women.

METHODS

Eighty-eight postmenopausal women aged 44-62 years were randomly allocated to daily: (1) conjugated equine estrogens 0.625 mg (CEE), (2) 17beta-estradiol 1mg plus norethisterone acetate 0.5mg (E(2)/NETA), (3) tibolone 2.5mg, (4) raloxifene HCl 60 mg or (5) no treatment. Serum monocyte chemoattractant protein-1 (MCP-1) and regulated upon activation, normal T-cell expressed and secreted (RANTES) were measured at baseline and at 3 months.

RESULTS

Endogenous testosterone and free androgen index (FAI) correlated negatively, while SHBG correlated positively with serum RANTES (testosterone: r=-0.27, p=0.033; FAI: r=-0.43, p=0.004: SHBG: r=0.34, p=0.026). Serum MCP-1 decreased significantly in the CEE group (baseline 125.3+/-51 pg/ml, 3 months 84.5+/-36.1 pg/ml, p=0.043), while no difference was detected between baseline and post-treatment levels in the other groups. Furthermore, a significant decrease in serum RANTES was observed at the end of 3 months only in the E2/NETA and the raloxifene group (E2/NETA baseline 8690.6+/-3880.0 pg/ml, 3 months 6894.0+/-1720.0 pg/ml, p=0.007; raloxifene baseline 9042.4+/-3765.6 pg/ml, 3 months 6718.1+/-2366.2 pg/ml, p=0.011).

CONCLUSION

Endogenous androgens may suppress chemotactic response. Postmenopausal hormone therapy and raloxifene may inhibit the expression of chemoattractant molecules and thus attenuate inflammation. The relevance of these findings in terms of clinically established caridoprotection remains to be clarified.

Neutrophils, lymphocytes, and monocytes exhibit diverse behaviors in transendothelial and subendothelial migrations under coculture with smooth muscle cells in disturbed flow

Atherosclerosis develops at regions of the arterial tree exposed to disturbed flow. The early stage of atherogenesis involves the adhesion of leukocytes (white blood cells [WBCs]) to and their transmigration across endothelial cells (ECs), which are located in close proximity to smooth muscle cells (SMCs). We investigated the effects of EC/SMC coculture and disturbed flow on the adhesion and transmigration of 3 types of WBCs (neutrophils, peripheral blood lymphocytes [PBLs], and monocytes) using our vertical-step flow (VSF) chamber, in which ECs were cocultured with SMCs in collagen gels. Such coculture significantly increased the adhesion and transmigration of neutrophils, PBLs, and monocytes under VSF, particularly in the reattachment area, where the rolling velocity of WBCs and their transmigration time were decreased, as compared with the other areas. Neutrophils, PBLs, and monocytes showed different subendothelial migration patterns under VSF. Their movements were more random and shorter in distance in the reattachment area. Coculture of ECs and SMCs induced their expressions of adhesion molecules and chemokines, which contributed to the increased WBC adhesion and transmigration. Our findings provide insights into the mechanisms of WBC interaction with the vessel wall (composed of ECs and SMCs) under the complex flow environments found in regions of prevalence for atherogenesis.

Chemokine RANTES is upregulated in monocytes from patients with hyperhomocysteinemia

AIM

To investigate the changes in plasma level of the chemokine RANTES (regulated upon activation, normal T cells expressed and secreted) and the responsiveness of lipopolysaccharide (LPS)-induced RANTES secretion from monocytes in patients with hyperhomocysteinemia (HHcy).

METHODS

The plasma levels of homocysteine (Hcy), folate, and RANTES were measured in 38 control patients with normal Hcy levels and 40 patients with HHcy and the mRNA synthesis of RANTES in isolated human monocytes was determined by RNase protection assays.

RESULTS

The plasma level of RANTES was elevated in HHcy patients compared with controls (median 5.3 vs 3.5 ng/mL, P<0.01). LPS-induced RANTES production from monocytes of HHcy patients was also increased significantly. In addition, Hcy directly increased the mRNA level of RANTES in isolated normal human monocytes in a time- and dose-dependent manner.

CONCLUSION

Upregulated RANTES from monocytes in HHcy patients may be involved in the atherogenesis of HHcy-induced atherosclerosis.