972 resultados para angiogenic and chemotactic chemokines
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Aldosterone is an important factor supporting placental growth and fetal development. Recently, expression of placental growth factor (PlGF) has been observed in response to aldosterone exposure in different models of atherosclerosis. Thus, we hypothesized that aldosterone up-regulates growth-adaptive angiogenesis in pregnancy, via increased placental PlGF expression. We followed normotensive pregnant women (n = 24) throughout pregnancy and confirmed these results in a second independent first trimester cohort (n = 36). Urinary tetrahydroaldosterone was measured by gas chromatography-mass spectrometry and corrected for creatinine. Circulating PlGF concentrations were determined by ELISA. Additionally, cultured cell lines, adrenocortical H295R and choriocarcinoma BeWo cells, as well as primary human third trimester trophoblasts were tested in vitro. PlGF serum concentrations positively correlated with urinary tetrahydroaldosterone corrected for creatinine in these two independent cohorts. This observation was not due to PlGF, which did not induce aldosterone production in cultured H295R cells. On the other hand, PlGF expression was specifically enhanced by aldosterone in the presence of forskolin (p < 0.01) in trophoblasts. A pronounced stimulation of PlGF expression was observed with reduced glucose concentrations simulating starvation (p < 0.001). In conclusion, aldosterone stimulates placental PlGF production, enhancing its availability during human pregnancy, a response amplified by reduced glucose supply. Given the crucial role of PlGF in maintaining a healthy pregnancy, these data support a key role of aldosterone for a healthy pregnancy outcome.
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Background: Resistance to targeted anti-angiogenic therapy is a growing clinical concern given the disappointing clinical impact of anti-angiogenic. Platelets represent a component of the tumor microenvironment that are implicated in metastasis and represent a significant reservoir of angiogenic regulators. Thrombocytosis has been shown to be caused by malignancy and associated with adverse clinical outcomes, however the causal connections between these associations remain to be identified. Materials and Methods: Following IRB approval, patient data were collected on patients from four U.S. centers and platelet levels through and after therapy were considered as indicators of recurrence of disease. In vitro effects of platelets on cancer cell proliferation, apoptosis, and migration were examined. RNA interference was used to query signaling pathways mediating these effects. The necessity of platelet activation for in vitro effect was analyzed. In vivo orthotopic models were used to query the impact of thrombocytosis and thrombocytopenia on the efficacy of cytotoxic chemotherapy, the effect of aspirin on thrombocytosis and cancer, and platelet effect on anti-angiogenic therapy. Results: Platelets were found to increase at the time of diagnosis of ovarian cancer recurrence in a pattern comparable to CA-125. Platelet co-culture increased proliferation, increased migration, and decreased apoptosis in all cell lines tested. RNA interference implicated platelet derived growth factor alpha (PDGFRA) and transforming growth factor beta-receptor 1 (TGFBR1) signaling. Biodistribution studies suggested minimal platelet sequestration of taxanes. Blockade of platelet activation blocked in vitro effects. In vivo, thrombocytosis blocked chemotherapeutic efficacy, thrombocytopenia increased chemotherapeutic efficacy, and aspirin therapy partially blocked the effects of thrombocytosis. In vivo, withdrawal of anti-angiogenic therapy caused loss of therapeutic benefit with evidence of accelerated disease growth. This effect was blocked by use of a small-molecule inhibitor of Focal Adhesion Kinase. Anti-angiogenic therapy was also associated with increased platelet infiltration into tumor that was not seen to the same degree in the control or FAK-inhibitor-treated mice. Conclusions: Platelets are active participants in the growth and metastasis of tumor, both directly and via facilitation of angiogenesis. Blocking platelets, blocking platelet activation, and blocking platelet trafficking into tumor are novel therapeutic avenues supported by this data. Copyright © 2012 Justin Neal Bottsford-Miller, all rights reserved.
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Many viruses have evolved mechanisms for evading the host immune system by synthesizing proteins that interfere with the normal immune response. The poxviruses are among the most accomplished at deceiving their hosts’ immune systems. The nucleotide sequence of the genome of the human cutaneous poxvirus, molluscum contagiosum virus (MCV) type 1, was recently reported to contain a region that resembles a human chemokine. We have cloned and expressed the chemokine-like genes from MCV type 1 and the closely related MCV type 2 to determine a potential role for these proteins in the viral life cycle. In monocyte chemotaxis assays, the viral proteins have no chemotactic activity but both viral proteins block the chemotactic response to the human chemokine, macrophage inflammatory protein (MIP)-1α. Like MIP-1α, both viral proteins also inhibit the growth of human hematopoietic progenitor cells, but the viral proteins are more potent in this activity than the human chemokine. These viral chemokines antagonize the chemotactic activity of human chemokines and have an inhibitory effect on human hematopoietic progenitor cells. We hypothesize that the inhibition of chemotaxis is an immune evasion function of these proteins during molluscum contagiosum virus infection. The significance of hematopoietic progenitor cell inhibition in viral pathogenesis is uncertain.
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The HIV-1 envelope protein gp120 induces apoptosis in hippocampal neurons. Because chemokine receptors act as cellular receptors for HIV-1, we examined rat hippocampal neurons for the presence of functional chemokine receptors. Fura-2-based Ca imaging showed that numerous chemokines, including SDF-1α, RANTES, and fractalkine, affect neuronal Ca signaling, suggesting that hippocampal neurons possess a wide variety of chemokine receptors. Chemokines also blocked the frequency of spontaneous glutamatergic excitatory postsynaptic currents recorded from these neurons and reduced voltage-dependent Ca currents in the same neurons. Reverse transcription–PCR demonstrated the expression of CCR1, CCR4, CCR5, CCR9/10, CXCR2, CXCR4, and CX3CR1, as well as the chemokine fractalkine in these neurons. Both fractalkine and macrophage-derived chemokine (MDC) produced a time-dependent activation of extracellular response kinases (ERK)-1/2, whereas no activation of c-JUN NH2-terminal protein kinase (JNK)/stress-activated protein kinase, or p38 was evident. Furthermore, these two chemokines, as well as SDF-1α, activated the Ca- and cAMP-dependent transcription factor CREB. Several chemokines were able also to block gp120-induced apoptosis of hippocampal neurons, both in the presence and absence of the glial feeder layer. These data suggest that chemokine receptors may directly mediate gp120 neurotoxicity.
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Pre-B-cell growth-stimulating factor/stromal cell-derived factor 1 (PBSF/SDF-1) is a member of the CXC group of chemokines that is initially identified as a bone marrow stromal cell-derived factor and as a pre-B-cell stimulatory factor. Although most chemokines are thought to be inducible inflammatory mediators, PBSF/SDF-1 is essential for perinatal viability, B lymphopoiesis, bone marrow myelopoiesis, and cardiac ventricular septal formation, and it has chemotactic activities on resting lymphocytes and monocytes. In this paper, we have isolated a cDNA that encodes a seven transmembrane-spanning-domain receptor, designated pre-B-cell-derived chemokine receptor (PB-CKR) from a murine pre-B-cell clone, DW34. The deduced amino acid sequence has 90% identity with that of a HUMSTSR/fusin, a human immunodeficiency virus 1 (HIV-1) entry coreceptor. However, the second extracellular region has lower identity (67%) compared with HUMSTSR/fusin. PB-CKR is expressed during embryo genesis and in many organs and T cells of adult mice. Murine PBSF/SDF-1 induced an increase in intracellular free Ca2+ in DW34 cells and PB-CKR-transfected Chinese hamster ovary (CHO) cells, suggesting that PB-CKR is a functional receptor for murine PBSF/SDF-1. Murine PBSF/SDF-1 also induced Ca2+ influx in fusin-transfected CHO cells. On the other hand, considering previous results that HIV-1 does not enter murine T cells that expressed human CD4, PB-CKR may not support HIV-1 infection. Thus, PB-CKR will be an important tool for functional mapping of HIV-1 entry coreceptor fusin and for understanding the function of PBSF/SDF-1 further.
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It has been demonstrated that CD8+ T cells produce a soluble factor(s) that suppresses human immunodeficiency virus (HIV) replication in CD4+ T cells. The role of soluble factors in the suppression of HIV replication in monocyte/macrophages (M/M) has not been fully delineated. To investigate whether a CD8+ T-cell-derived soluble factor(s) can also suppress HIV infection in the M/M system, primary macrophages were infected with the macrophage tropic HIV-1 strain Ba-L. CD8+ T-cell-depleted peripheral blood mononuclear cells were also infected with HIV-1 IIIB or Ba-L. HIV expression from the chronically infected macrophage cell line U1 was also determined in the presence of CD8+ T-cell supernatants or β-chemokines. We demonstrate that: (i) CD8+ T-cell supernatants did, but β-chemokines did not, suppress HIV replication in the M/M system; (ii) antibodies to regulated on activation normal T-cell expressed and Secreted (RANTES), macrophage inflammatory protein 1α (MIP-1α) and MIP-1β did not, whereas antibodies to interleukin 10, interleukin 13, interferon α, or interferon γ modestly reduced anti-HIV activity of the CD8+ T-cell supernatants; and (iii) the CD8+ T-cell supernatants did, but β-chemokines did not, suppress HIV-1 IIIB replication in peripheral blood mononuclear cells as well as HIV expression in U1 cells. These results suggest that HIV-suppressor activity of CD8+ T cells is a multifactorial phenomenon, and that RANTES, MIP-1α, and MIP-1β do not account for the entire scope of CD8+ T-cell-derived HIV-suppressor factors.
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CYR61 is a secreted, cysteine-rich, heparin-binding protein encoded by a growth factor-inducible immediate–early gene. Acting as an extracellular, matrix-associated signaling molecule, CYR61 promotes the adhesion of endothelial cells through interaction with the integrin αVβ3 and augments growth factor-induced DNA synthesis in the same cell type. In this study, we show that purified CYR61 stimulates directed migration of human microvascular endothelial cells in culture through an αVβ3-dependent pathway and induces neovascularization in rat corneas. Both the chemotactic and angiogenic activities of CYR61 can be blocked by specific anti-CYR61 antibodies. Whereas most human tumor-derived cell lines tested express CYR61, the gastric adenocarcinoma cell line RF-1 does not. Expression of the CYR61 cDNA under the regulation of a constitutive promoter in RF-1 cells significantly enhances the tumorigenicity of these cells as measured by growth in immunodeficient mice, resulting in tumors that are larger and more vascularized than those produced by control RF-1 cells. Taken together, these results identify CYR61 as an angiogenic inducer that can promote tumor growth and vascularization; the results also suggest potential roles for CYR61 in physiologic and pathologic neovascularization.
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One of the obstacles to AIDS vaccine development is the variability of HIV-1 within individuals and within infected populations, enabling viral escape from highly specific vaccine induced immune responses. An understanding of the different immune mechanisms capable of inhibiting HIV infection may be of benefit in the eventual design of vaccines effective against HIV-1 variants. To study this we first compared the immune responses induced in Rhesus monkeys by using two different immunization strategies based on the same vaccine strain of HIV-1. We then utilized a chimeric simian/HIV that expressed the envelope of a dual tropic HIV-1 escape variant isolated from a later time point from the same patient from which the vaccine strain was isolated. Upon challenge, one vaccine group was completely protected from infection, whereas all of the other vaccinees and controls became infected. Protected macaques developed highest titers of heterologous neutralizing antibodies, and consistently elevated HIV-1-specific T helper responses. Furthermore, only protected animals had markedly increased concentrations of RANTES, macrophage inflammatory proteins 1α and 1β produced by circulating CD8+ T cells. These results suggest that vaccine strategies that induce multiple effector mechanisms in concert with β-chemokines may be desired in the generation of protective immune responses by HIV-1 vaccines.
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The CC chemokines regulated on activation normal T expressed and secreted (RANTES) and monocyte chemotactic protein 3 (MCP-3), and the anaphylatoxin C5a, induce activation, degranulation, chemotaxis, and transendothelial migration of eosinophils. Adhesion assays on purified ligands showed differential regulation of beta 1 and beta 2 integrin avidity in eosinophils. Adhesiveness of VLA-4 (alpha 4 beta 1, CD29/CD49d) for vascular cell adhesion molecule 1 or fibronectin was rapidly increased but subsequently reduced by RANTES, MCP-3, or C5a. The deactivation of VLA-4 lead to cell detachment, whereas phorbol 12-myristate 13-acetate induced sustained activation of VLA-4. In contrast, chemoattractants stimulated a prolonged increase in the adhesiveness of Mac-1 (alpha M beta 2, CD11b/CD18) for intercellular adhesion molecule 1. Inhibition by pertussis toxin confirmed signaling via G protein-coupled receptors. Chemoattractants induced transient, while phorbol 12-myristate 13-acetate induced sustained actin polymerization. Disruption of actin filaments by cytochalasins inhibited increases in avidity of VLA-4 but not of Mac-1. Chemoattractants did not upregulate a Mn2+-inducible beta 1 neoepitope defined by the mAb 9EG7, but induced prolonged expression of a Mac-1 activation epitope recognized by the mAb CBRM1/5. This mAb inhibited chemoattractant-stimulated adhesion of eosinophils to intercellular adhesion molecule 1. Thus, regulation of VLA-4 was dependent on the actin cytoskeleton, whereas conformational changes appeared to be crucial for activation of Mac-1. To our knowledge, this is the first demonstration that physiological agonists, such as chemoattractants, can differentially regulate the avidity of a beta 1 and a beta 2 integrin expressed on the same leukocyte.
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In humans, only a small fraction (2-12%) of a sperm population can respond by chemoattraction to follicular factors. This recent finding led to the hypothesis that chemotaxis provides a mechanism for selective recruitment of functionally mature spermatozoa (i.e., of capacitated spermatozoa, which possess the potential to undergo the acrosome reaction and fertilize the egg). This study aimed to examine this possibility. Capacitated spermatozoa were identified by their ability to undergo the acrosome reaction upon stimulation with phorbol 12-myristate 13-acetate. Under capacitating conditions, only a small portion (2-14%) of the spermatozoa were found to be capacitated. The spermatozoa were then separated according to their chemotactic activity, which resulted in a subpopulation enriched with chemotactically responsive spermatozoa and a subpopulation depleted of such spermatozoa. The level of capacitated spermatozoa in the former was approximately 13-fold higher than that in the latter. The capacitated state was temporary (50 min < life span < 240 min), and it was synchronous with the chemotactic activity. A continuous process of replacement of capacitated/chemotactic spermatozoa within a sperm population was observed. Spermatozoa that had stopped being capacitated did not become capacitated again, which indicates that the capacitated state is acquired only once in a sperm's lifetime. A total sperm population depleted of capacitated spermatozoa stopped being chemotactic. When capacitated spermatozoa reappeared, chemotactic activity was restored. These observations suggest that spermatozoa acquire their chemotactic responsiveness as part of the capacitation process and lose this responsiveness when the capacitated state is terminated. We suggest that the role of sperm chemotaxis in sperm-egg interaction in vivo may indeed be selective recruitment of capacitated spermatozoa for fertilizing the egg.
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Adjuvants are substances that enhance immune responses and thus improve the efficacy of vaccination. Few adjuvants are available for use in humans, and the one that is most commonly used (alum) often induces suboptimal immunity for protection against many pathogens. There is thus an obvious need to develop new and improved adjuvants. We have therefore taken an approach to adjuvant discovery that uses in silico modeling and structure-based drug-design. As proof-of-principle we chose to target the interaction of the chemokines CCL22 and CCL17 with their receptor CCR4. CCR4 was posited as an adjuvant target based on its expression on CD4(+)CD25(+) regulatory T cells (Tregs), which negatively regulate immune responses induced by dendritic cells (DC), whereas CCL17 and CCL22 are chemotactic agents produced by DC, which are crucial in promoting contact between DC and CCR4(+) T cells. Molecules identified by virtual screening and molecular docking as CCR4 antagonists were able to block CCL22- and CCL17-mediated recruitment of human Tregs and Th2 cells. Furthermore, CCR4 antagonists enhanced DC-mediated human CD4(+) T cell proliferation in an in vitro immune response model and amplified cellular and humoral immune responses in vivo in experimental models when injected in combination with either Modified Vaccinia Ankara expressing Ag85A from Mycobacterium tuberculosis (MVA85A) or recombinant hepatitis B virus surface antigen (rHBsAg) vaccines. The significant adjuvant activity observed provides good evidence supporting our hypothesis that CCR4 is a viable target for rational adjuvant design.
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Osteochondral tissue repair requires formation of vascularized bone and avascular cartilage. Mesenchymal stem cells stimulate angiogenesis both in vitro and in vivo but it is not known if these proangiogenic properties change as a result of chondrogenic or osteogenic differentiation. We investigated the angiogenic/antiangiogenic properties of equine bone marrow-derived mesenchymal stem cells (eBMSCs) before and after differentiation in vitro. Conditioned media from chondrogenic and osteogenic cell pellets and undifferentiated cells was applied to endothelial tube formation assays using Matrigel™. Additionally, the cell secretome was analysed using LC-MS/MS mass spectrometry and screened for angiogenesis and neurogenesis-related factors using protein arrays. Endothelial tube-like formation was supported by conditioned media from undifferentiated eBMSCs. Conversely, chondrogenic and osteogenic conditioned media was antiangiogenic as shown by significantly decreased length of endothelial tube-like structures and degree of branching compared to controls. Undifferentiated cells produced higher levels of angiogenesis-related proteins compared to chondrogenic and osteogenic pellets. In summary, eBMSCs produce an array of angiogenesis-related proteins and support angiogenesis in vitro via a paracrine mechanism. However, when these cells are differentiated chondrogenically or osteogenically, they produce a soluble factor(s) that inhibits angiogenesis. With respect to osteochondral tissue engineering, this may be beneficial for avascular articular cartilage formation but unfavourable for bone formation where a vascularized tissue is desired. © Copyright 2014, Mary Ann Liebert, Inc.
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Spontaneous fetal loss (25-40%) leading to decrease in litter size is a significant concern to the pork industry. A deficit in the placental vasculature has emerged as one of the important factors associated with fetal loss. During early pig pregnancy, the endometrium becomes enriched with immune cells recruited by conceptus-derived signals including specific chemokine stimuli. These immune cells assist in various aspects of placental development and angiogenesis. Recent evidence suggests that microRNAs (miRNAs: small non-coding RNAs that regulate gene expression) regulate immune cell development and their functions. In addition, intercellular communication including exchange of biomolecules (e.g. miRNAs) between the conceptus and endometrium regulate key developmental processes during pregnancy. To understand the biological significance of immune cell enrichment, regulation of their functions by miRNAs and transfer of miRNAs across the maternal fetal-interface, we screened specific sets of chemokines and pro- and anti-angiogenic miRNAs in endometrial lymphocytes (ENDO LY), endometrium, and chorioallantoic membrane (CAM) isolated from conceptus attachment sites (CAS) during early, gestation day (gd)20 and mid-pregnancy (gd50). We report increased expression of selected chemokines including CXCR3 and CCR5 in ENDO LY and CXCL10, CXCR3, CCL5, CCR5 in endometrium associated with arresting CAS at gd20. Some of these differences were also noted at the protein level (CXCL10, CXCR3, CCL5, and CCR5) in endometrium and CAM. We report for the first time significant differences for miRNAs involved in immune cell-derived angiogenesis (miR-296-5P, miR-150, miR-17P-5P, miR-18a, and miR-19a) between ENDO LY associated with healthy and arresting CAS. Significant differences were also found in endometrium and CAM for some miRNAs (miR-17-5P, miR-18a, miR-15b-5P, and miR-222). Finally, we confirm that placenta specific-exosomes contain proteins and 14 select miRNAs including miR-126-5P, miR-296-5P, miR-16, and miR-17-5P that are of relevance to early implantation events. We further demonstrated the bidirectional exosome shuttling between porcine trophectoderm cells (PTr2) and porcine aortic endothelial cells (PAOEC). PTr2-derived exosomes were able to modulate the endothelial cell proliferation that is crucial for the establishment of pregnancy. Our data unravels the selected chemokines and miRNAs associated with immune cell-regulated angiogenesis and reconfirm that exosome mediated cell-cell communication opens-up new avenues to understand porcine pregnancy.
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Cardiovascular disease (CVD) is the biggest killer of people in western civilisation. Age is a significant risk factor for the development for CVD, and treatments and therapies to address this increased risk are crucial to quality of life and longevity. Exercise is one such intervention which has been shown to reduce CVD risk. Age is also associated with endothelial dysfunction, reduced angiogenic capabilities, and reduced ability to repair the vessel wall. Circulating angiogenic cells (CACs) are a subset of circulating cells which assist in the repair and growth of the vasculature and in the maintenance of endothelial function. Reductions in these cells are observed in those with vascular disease compared to age-matched healthy controls. Exercise may reduce CVD risk by improvements in number and/or function of these CACs. Data was collected from human volunteers of various ages, cardiorespiratory fitness (CRF) levels and latent viral infection history status to investigate the effects of chronological age, CRF, viral serology and other lifestyle factors, such as sedentary behaviours and exercise on CACs. The levels of CACs in these volunteers were measured using four colour flow cytometry using various monoclonal antibodies specific to cell surface markers that are used to identify specific subsets of these CACs. In addition, the response to acute exercise of a specific subset of these CACs, termed ‘angiogenic T-cells’ (TANG) were investigated, in a group of well-trained males aged 20-40 years, using a strenuous submaximal exercise bout. Advancing age was associated with a decline in various subsets of CACs, including bone marrow-derived CD34+ progenitors, putative endothelial progenitor cells (EPCs) and also TANG cells. Individuals with a higher CRF were more likely to have higher circulating numbers of TANG cells, particularly in the CD4+ subset. CRF did not appear to modulate CD34+ progenitors or EPC subsets. Increasing sitting time was associated with reduction in TANG cells, but after correcting for the effects of fitness, sitting time no longer negatively affected the circulating number of these cells. Acute exercise was a powerful stimulus for increasing the number of TANG cells (140% increase), potentially through an SDF-1:CXCR4-dependent mechanism, but more studies are required to investigate this. Latent CMV infection was associated with higher number of TANG cells (CD8+), but only in 18-40 year old individuals, and not in an older age group (41-65 year old). The significance of this has yet to be understood. In conclusion, advancing age may contribute to increased CVD risk partly due to the observed reductions in angiogenic cells circulating in the peripheral compartment. Maintaining a high CRF may attenuate this CVD reduction by modulating TANG cell number, but potentially not CD34+ progenitor or EPC subsets. Acute exercise may offer a short window for vascular adaptation through the mobilisation of TANG cells into the circulation.
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Introduction: Among the inflammatory mediators involved in the pathogenesis of obesity, the cell adhesion molecules P-selectin, E-selectin, VCAM-1, ICAM-1 and the chemokine MCP-1 stand out. They play a crucial role in adherence of cells to endothelial surfaces, in the integrity of the vascular wall and can be modulated by body composition and dietary pattern. Objectives: To describe and discuss the relation of these cell adhesion molecules and chemokines to anthropometric, body composition, dietary and biochemical markers. Methods: Papers were located using scientific databases by topic searches with no restriction on year of publication. Results: All molecules were associated positively with anthropometric markers, but controversial results were found for ICAM-1 and VCAM-1. Not only obesity, but visceral fat is more strongly correlated with E-selectin and MCP-1 levels. Weight loss influences the reduction in the levels of these molecules, except VCAM-1. The distribution of macronutrients, excessive consumption of saturated and trans fat and a Western dietary pattern are associated with increased levels. The opposite could be observed with supplementation of w-3 fatty acid, healthy dietary pattern, high calcium diet and high dairy intake. Regarding the biochemical parameters, they have inverse relation to HDLC and positive relation to total cholesterol, triglycerides, blood glucose, fasting insulin and insulin resistance. Conclusion: Normal anthropometric indicators, body composition, biochemical parameters and eating pattern positively modulate the subclinical inflammation that results from obesity by reducing the cell adhesion molecules and chemokines.