Targeting systemic inflammation in metabolic disorders. A therapeutic candidate for the prevention of cardiovascular diseases?

Cardiovascular disease (CVD) remains the leading cause of death and disability worldwide. While many factors can contribute to CVD, atherosclerosis is the cardinal underlying pathology, and its development is associated with several metabolic risk factors including dyslipidemia and obesity. Recent studies have definitively demonstrated a link between low-grade systemic inflammation and two relevant metabolic abnormalities: hypercholesterolemia and obesity. Interestingly, both metabolic disorders are also associated with endothelial dysfunction/activation, a proinflammatory and prothrombotic phenotype of the endothelium that involves leukocyte infiltration into the arterial wall, one of the earliest stages of atherogenesis. This article reviews the current literature on the intricate relationship between hypercholesterolemia and obesity and the associated systemic inflammation and endothelial dysfunction, and discusses the effectiveness of present, emerging and in-development pharmacological therapies used to treat these metabolic disorders with a focus on their effects on the associated systemic inflammatory state and cardiovascular risk.

Prostate Cancer and the Mevalonate Pathway.

Antineoplastic therapies for prostate cancer (PCa) have traditionally centered around the androgen receptor (AR) pathway, which has demonstrated a significant role in oncogenesis. Nevertheless, it is becoming progressively apparent that therapeutic strategies must diversify their focus due to the emergence of resistance mechanisms that the tumor employs when subjected to monomolecular treatments. This review illustrates how the dysregulation of the lipid metabolic pathway constitutes a survival strategy adopted by tumors to evade eradication efforts. Integrating this aspect into oncological management could prove valuable in combating PCa.

L-selectin regulates human neutrophil transendothelial migration.

The migration of circulating neutrophils towards damaged or infected tissue is absolutely critical to the inflammatory response. L-selectin is a cell adhesion molecule abundantly expressed on circulating neutrophils. For over two decades, neutrophil L-selectin has been assigned the exclusive role of supporting tethering and rolling - the initial stages of the multi-step adhesion cascade. Here, we provide direct evidence for L-selectin contributing to neutrophil transendothelial migration (TEM). We show that L-selectin co-clusters with PECAM-1 - a well-characterised cell adhesion molecule involved in regulating neutrophil TEM. This co-clustering behaviour occurs specifically during TEM, which serves to augment ectodomain shedding of L-selectin and expedite the time taken for TEM (TTT) to complete. Blocking PECAM-1 signalling (through mutation of its cytoplasmic tail), PECAM-1-dependent adhesion or L-selectin shedding, leads to a significant delay in the TTT. Finally, we show that co-clustering of L-selectin with PECAM-1 occurs specifically across TNF- but not IL-1ß-activated endothelial monolayers - implying unique adhesion interactomes forming in a cytokine-specific manner. To our knowledge, this is the first report to implicate a non-canonical role for L-selectin in regulating neutrophil TEM.

Anti-inflammatory effects and improved metabolic derangements in ob/ob mice by a newly synthesized prenylated benzopyran with pan-PPAR activity.

BACKGROUND AND PURPOSE: Selective peroxisome proliferator-activated receptors (PPARs) are widely used to treat metabolic complications; however, the limited effect of PPARα agonists on glucose metabolism and the adverse effects associated with selective PPARγ activators have stimulated the development of novel pan-PPAR agonists to treat metabolic disorders. Here, we synthesized a new prenylated benzopyran (BP-2) and evaluated its PPAR-activating properties, anti-inflammatory effects and impact on metabolic derangements. EXPERIMENTAL APPROACH: BP-2 was used in transactivation assays to evaluate its agonism to PPARα, PPARß/δ and PPARγ. A parallel-plate flow chamber was employed to investigate its effect on TNFα-induced leukocyte-endothelium interactions. Flow cytometry and immunofluorescence were used to determine its effects on the expression of endothelial cell adhesion molecules (CAMs) and chemokines and p38-MAPK/NF-κB activation. PPARs/RXRα interactions were determined using a gene silencing approach. Analysis of its impact on metabolic abnormalities and inflammation was performed in ob/ob mice. KEY RESULTS: BP-2 displayed strong PPARα activity, with moderate and weak activity against PPARß/δ and PPARγ, respectively. In vitro, BP-2 reduced TNFα-induced endothelial ICAM-1, VCAM-1 and fractalkine/CX3CL1 expression, suppressed mononuclear cell arrest via PPARß/δ-RXRα interactions and decreased p38-MAPK/NF-κB activation. In vivo, BP-2 improved the circulating levels of glucose and triglycerides in ob/ob mice, suppressed T-lymphocyte/macrophage infiltration and proinflammatory markers in the liver and white adipose tissue, but increased the expression of the M2-like macrophage marker CD206. CONCLUSION AND IMPLICATIONS: BP-2 emerges as a novel pan-PPAR lead candidate to normalize glycemia/triglyceridemia and minimize inflammation in metabolic disorders, likely preventing the development of further cardiovascular complications.

Overview of Cellular and Soluble Mediators in Systemic Inflammation Associated with Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) is currently the most prevalent chronic liver disease in Western countries, affecting approximately 25% of the adult population. This condition encompasses a spectrum of liver diseases characterized by abnormal accumulation of fat in liver tissue (non-alcoholic fatty liver, NAFL) that can progress to non-alcoholic steatohepatitis (NASH), characterized by the presence of liver inflammation and damage. The latter form often coexists with liver fibrosis which, in turn, may progress to a state of cirrhosis and, potentially, hepatocarcinoma, both irreversible processes that often lead to the patient's death and/or the need for liver transplantation. Along with the high associated economic burden, the high mortality rate among NAFLD patients raises interest, not only in the search for novel therapeutic approaches, but also in early diagnosis and prevention to reduce the incidence of NAFLD-related complications. In this line, an exhaustive characterization of the immune status of patients with NAFLD is mandatory. Herein, we attempted to gather and compare the current and relevant scientific evidence on this matter, mainly on human reports. We addressed the current knowledge related to circulating cellular and soluble mediators, particularly platelets, different leukocyte subsets and relevant inflammatory soluble mediators.

Association of chemokines IP-10/CXCL10 and I-TAC/CXCL11 with insulin resistance and enhance leukocyte endothelial arrest in obesity.

BACKGROUND AND AIMS: Obesity is a key contributing factor to incidental type 2 diabetes and cardiovascular disease. CXCR3 receptor and its ligands CXCL 10 and 11 are associated with atherosclerosis and cardiovascular disease. The aim of our study was to analyse the role of the CXCR3 ligands on insulin resistance (IR) and endothelial dysfunction in human obesity. METHODS AND RESULTS: We have studied 45 obese patients (mean age 44 ± 6 years, body mass index 45 ± 9 kg/m2) who were selected for Roux-Y-gastric bypass surgery and 21 non obese control subjects with similar age and gender distribution. We measured by ELISA the circulating levels of the CXCR3 ligands interferon-γ inducible protein 10 (IP-10/CXCL10) and interferon-γ-inducible T-cell alpha chemoattractant (I-TAC/CXCL11). Using an ex vivo procedure with the flow chamber assay, we have investigated the effect of such chemokines on endothelial leukocytes arrest under dynamic conditions. Peripheral blood levels of CXCL10 and CXCL11 were significantly higher in obese subjects than in controls (p < 0.001) and significantly correlated with BMI, waist circunference and HOMA-IR. Obese patients with HOMA-IR index above 75th percentile showed highest increase of circulating CXCL10 and CXCL11 values. Under dynamic flow conditions, the enhanced adhesion of patient leukocytes to TNFα-induced human arterial endothelial cells was partly dependent on CXCR3. CONCLUSIONS: The study demonstrates that CXCL10 and CXCL11 are associated with IR and enhance leukocyte endothelial arrest in obese subjects. Blockade of CXCR3 signaling might be a new therapeutic approach for the prevention of obesity-associated cardiovascular co-morbidities.

Synthesis and biological studies of "Polycerasoidol" and "trans-δ-Tocotrienolic acid" derivatives as PPARα and/or PPARγ agonists.

2-Prenylated benzopyrans represent a class of natural and synthetic compounds showing a wide range of significant activities. Polycerasoidol is a natural prenylated benzopyran isolated from the stem bark of Polyalthia cerasoides (Annonaceae) that exhibits dual PPARα/γ agonism and an anti-inflammatory effect by inhibiting mononuclear leukocyte adhesion to the dysfunctional endothelium. Herein, we report the synthesis of three new series of prenylated benzopyrans containing one (series 1), two (series 2, "polycerasoidol" analogs) and three (series 3, "trans-δ-tocotrienolic acid" analogs) isoprenoid units in the hydrocarbon side chain at the 2-position of the chroman-6-ol (6-hydroxy-dihydrobenzopyran) scaffold. Isoprenoid moieties were introduced through a Grignard reaction sequence, followed by Johnson-Claisen rearrangement and subsequent Wittig olefination. hPPAR transactivation activity and the structure activity relationships (SAR) of eleven novel synthesized 2-prenylated benzopyrans were explored. PPAR transactivation activity demonstrated that the seven-carbon side chain analogs (series 1) displayed selectivity for hPPARα, while the nine-carbon side chain analogs (polycerasoidol analogs, series 2) did so for hPPARγ. The side chain elongation to 11 or 13 carbons (series 3) resulted in weak dual PPARα/γ activation. Therefore, 2-prenylated benzopyrans of seven- and nine-carbon side chain (polycerasoidol analogs) are good lead compounds for developing useful candidates to prevent cardiovascular diseases associated with metabolic disorders.

Revealing 2-dimethylhydrazino-2-alkyl alkynyl sphingosine derivatives as sphingosine kinase 2 inhibitors: Some hints on the structural basis for selective inhibition.

Sphingosine kinase (SphK), which catalyzes the transfer of phosphate from ATP to sphingosine (Sph) generating sphingosine-1-phosphate (S1P) has emerged as therapeutic target since the discovery of connections of S1P with cancer progress. So far, most effort has focused on the development of inhibitors of SphK1, and selective inhibitors of SphK2 have been much less explored. Here, we describe the syntheses of new sphingosine derivatives bearing a tetrasubstituted carbon atom at C-2, dimethylhydrazino or azo moieties in the polar head, and alkane, alkene or alkyne moieties as linkers between the polar ahead and the fatty tail. In vitro inhibitory assays based on a time resolved fluorescence energy transfer (TR-FRET) have revealed the hydrazino and alkynyl moieties as the best combination for the design of selective SphK2 inhibitors (19a and 19b). Docking studies showed that compounds 19a-b have the optimal binding to SphK2 through the exploitation of polar but also hydrophobic interactions of their head group with the head of the enzyme binding pocket, while also producing full contact of the fatty tail with the hydrophobic pocket of the enzyme. By contrast, this elongation causes loss of contact surface with the shorter hydrophobic toe of the SphK1 isoform, thus accounting for the SphK2-biased selectivity of these compounds. Cell viability assays of the most promising candidates 19a-b have shown that 19a is not cytotoxic to human endothelial cells at 30 µM.

The nuclear retinoid-related orphan receptor RORα controls adipose tissue inflammation in patients with morbid obesity and diabetes.

BACKGROUND/AIMS: Inflammation governs adipose tissue (AT) dysfunction in obesity. Retinoic acid receptor-related orphan receptor alpha (RORα) is associated with inflammation and insulin resistance in animal studies, but its role in human obesity remains elusive. We investigated the expression and function of RORα on AT inflammation in patients with morbid obesity with/without diabetes. SUBJECTS/METHODS: We assessed RORα expression in paired biopsies of subcutaneous and omental AT from 41 patients (body mass index (BMI) 43.3 ± 0.8 kg/m2) during Roux-en-Y-gastric surgery and explored the functional consequences of pharmacological RORα blockade in AT ex vivo. RESULTS: RORα expression was significantly higher in omental AT than in subcutaneous AT (p = 0.03) and was positively associated with BMI (r = 0.344, p = 0.027) and homeostasis model assessment of insulin resistance (r = 0.319, p = 0.041). In ex vivo assays, IL-8/CXCL8 and MCP-1/CCL2 chemokine release was significantly higher in omental fat explants from diabetic patients than from non-diabetics and was significantly diminished by RORα blockade (p < 0.05). Inhibition of RORα improved protein kinase B signaling and decreased NF-κB activity in omental AT from patients with diabetes (p < 0.05). Under dynamic flow conditions, RORα blockade prevented mononuclear cell attachment to human dysfunctional endothelial cells. CONCLUSIONS: RORα blockade represents a potential therapy to prevent AT dysfunction and inflammation associated with insulin resistance in human obesity.

An updated overview of e-cigarette impact on human health.

The electronic cigarette (e-cigarette), for many considered as a safe alternative to conventional cigarettes, has revolutionised the tobacco industry in the last decades. In e-cigarettes, tobacco combustion is replaced by e-liquid heating, leading some manufacturers to propose that e-cigarettes have less harmful respiratory effects than tobacco consumption. Other innovative features such as the adjustment of nicotine content and the choice of pleasant flavours have won over many users. Nevertheless, the safety of e-cigarette consumption and its potential as a smoking cessation method remain controversial due to limited evidence. Moreover, it has been reported that the heating process itself can lead to the formation of new decomposition compounds of questionable toxicity. Numerous in vivo and in vitro studies have been performed to better understand the impact of these new inhalable compounds on human health. Results of toxicological analyses suggest that e-cigarettes can be safer than conventional cigarettes, although harmful effects from short-term e-cigarette use have been described. Worryingly, the potential long-term effects of e-cigarette consumption have been scarcely investigated. In this review, we take stock of the main findings in this field and their consequences for human health including coronavirus disease 2019 (COVID-19).

Peripheral blood levels of CXCL10 are a useful marker for diabetic polyneuropathy in subjects with type 2 diabetes.

BACKGROUND: Diabetic peripheral neuropathy (DPN) is a chronic complication of diabetes mellitus associated with high morbidity and mortality. Major risk factors for DPN include metabolic changes, duration of diabetes, nerve ischaemia and derangements in regeneration and nerve repair programmes. Chemokines have been previously implicated in the pathogenesis of various neuropathies and neuropathic pain processes. The aim of this pilot study was to evaluate the association between the plasma levels of chemokines (CXCL9, CXCL10 and CXCL11) in the presence of DPN in a cohort of type 2 diabetes (T2D) patients. MATERIALS AND METHODS: We studied 73 patients with T2D: 36 with DPN and 37 without DPN. DPN was established through the Semmes-Weinstein test (SW). Plasma levels of circulating chemokines CXCL9, CXCL10 and CXCL11 were determined using DuoSet ELISA kits (Abingdon, UK). RESULTS: We found that levels of CXCL10 were significantly higher in patients with DPN than amongst patients without DPN (57.6 ± 38.3 vs 38.1 ± 33.4 pg/mL, respectively; P = .034). Serum levels of chemokine CXCL9 were also higher amongst patients with DPN but did not reach a statistical significance (188.1 ± 72.7 and 150.4 ± 83.6 pg/mL, respectively, P = .06). CONCLUSIONS: Increased circulating levels of CXCL10 were associated with DPN in T2D patients, suggesting a role of this chemokine in the DPN. Determination of CXCL10 levels could be used as a marker for the early detection and implementation of therapeutic strategies in order to reverse and prevent the DPN.

Postprandial triglyceridaemia is modulated by insulin resistance but not by grade of obesity in abdominal and morbid obese subjects.

BACKGROUND: Obesity is associated with high cardiovascular risk. Postprandial lipidaemia has been associated with cardiovascular disease risk. Our aim was to identify whether anthropometric parameters, insulin resistance (IR) and/or fasting plasma triglycerides may determine postprandial changes in lipoprotein concentrations in abdominal and morbid obese subjects. METHODS: We have studied 20 non-diabetic, normolipidaemic subjects with abdominal obesity, 20 morbid obese subjects and 20 healthy individuals, that have similar age and gender. In all of them a standardised oral fat load test (OFLT) with unsaturated fat was performed. RESULTS: During the OFLT, the postprandial triglycerides response was significantly higher in subjects with abdominal obesity compared with morbid obese subjects (4 hours triglycerides pick value and AUC of triglycerides). Both obese groups showed significantly higher postprandial triglycerides response compared with healthy subjects. Dividing the obesity group according to the presence of IR, we found that IR was an important factor related with postprandial lipaemia but not BMI or waist circumference. In addition, postprandial glycaemia and insulinaemia significantly decreased in all studied subjects, being the highest decrease in morbid obese subjects and in subjects with IR. Postprandial triglyceridaemia significantly correlated with IR parameters and not with anthropometric parameters in AO and MO subjects. CONCLUSION: In subjects with AO and MO, postprandial triglycerides values are higher than healthy individuals and independently predicted by fasting IR parameters. Furthermore, unsaturated fat improved IR state.

Activation of the Constitutive Androstane Receptor Inhibits Leukocyte Adhesiveness to Dysfunctional Endothelium.

Leukocyte cell recruitment into the vascular subendothelium constitutes an early event in the atherogenic process. As the effect of the constitutive androstane receptor (CAR) on leukocyte recruitment and endothelial dysfunction is poorly understood, this study investigated whether the role of CAR activation can affect this response and the underlying mechanisms involved. Under physiological flow conditions, TNFα-induced endothelial adhesion of human leukocyte cells was concentration-dependently inhibited by preincubation of human umbilical arterial endothelial cells with the selective human CAR ligand CITCO. CAR agonism also prevented TNFα induced VCAM-1 expression, as well as MCP-1/CCL-2 and RANTES/CCL-5 release in endothelial cells. Suppression of CAR expression with a small interfering RNA abrogated the inhibitory effects of CITCO on these responses. Furthermore, CITCO increased interaction of CAR with Retinoid X Receptor (RXR) and reduced TNFα-induced p38-MAPK/NF-κB activation. In vivo, using intravital microscopy in the mouse cremasteric microcirculation treatment with the selective mouse CAR ligand TCPOBOP inhibited TNFα-induced leukocyte rolling flux, adhesion, and emigration and decreased VCAM-1 in endothelium. These results reveal that CAR agonists can inhibit the initial inflammatory response that precedes the atherogenic process by targeting different steps in the leukocyte recruitment cascade. Therefore, CAR agonists may constitute a new therapeutic tool in controlling cardiovascular disease-associated inflammatory processes.

SGLT-2 (Sodium-Glucose Cotransporter 2) Inhibition Reduces Ang II (Angiotensin II)-Induced Dissecting Abdominal Aortic Aneurysm in ApoE (Apolipoprotein E) Knockout Mice.

OBJECTIVE: Abdominal aortic aneurysm (AAA) is a pathological condition of permanent vessel dilatation that predisposes to the potentially fatal consequence of aortic rupture. SGLT-2 (sodium-glucose cotransporter 2) inhibitors have emerged as powerful pharmacological tools for type 2 diabetes mellitus treatment. Beyond their glucose-lowering effects, recent studies have shown that SGLT-2 inhibitors reduce cardiovascular events and have beneficial effects on several vascular diseases such as atherosclerosis; however, the potential effects of SGLT-2 inhibition on AAA remain unknown. This study evaluates the effect of oral chronic treatment with empagliflozin-an SGLT-2 inhibitor-on dissecting AAA induced by Ang II (angiotensin II) infusion in apoE (apolipoprotein E)-/- mice. Approach and Results: Empagliflozin treatment significantly reduced the Ang II-induced increase in maximal suprarenal aortic diameter in apoE-/- mice independently of blood pressure effects. Immunohistochemistry analysis revealed that empagliflozin diminished Ang II-induced elastin degradation, neovessel formation, and macrophage infiltration at the AAA lesion. Furthermore, Ang II infusion resulted in a marked increase in the expression of chemokines (CCL-2 [chemokine (C-C motif) ligand 2] and CCL-5 [chemokine (C-C motif) ligand 5]), VEGF (vascular endothelial growth factor), and MMP (matrix metalloproteinase)-2 and MMP-9 in suprarenal aortic walls of apoE-/- mice, and all were reduced by empagliflozin cotreatment. Western blot analysis revealed that p38 MAPK (p38 mitogen-activated protein kinase) and NF-κB (nuclear factor-κB) activation was also reduced in the suprarenal aortas of apoE-/- mice cotreated with empagliflozin. Finally, in vitro studies in human aortic endothelial cells and macrophages showed that empagliflozin inhibited leukocyte-endothelial cell interactions and release of proinflammatory chemokines. CONCLUSIONS: Pharmacological inhibition of SGLT-2 by empagliflozin inhibits AAA formation. SGLT-2 inhibition might represent a novel promising therapeutic strategy to prevent AAA progression.

1-(2'-Bromobenzyl)-6,7-dihydroxy-N-methyl-tetrahydroisoquinoline and 1,2-Demethyl-nuciferine as Agonists in Human D2 Dopamine Receptors.

Certain D2-like dopamine receptor (DR) agonists are useful therapeutically as antiparkinsonian drugs, whereas D2-like DR antagonists or partial agonists are proven effective as antipsychotics. Two isoquinoline derivatives, 1-(2'-bromobenzyl)-6,7-dihydroxy-N-methyl-tetrahydroisoquinoline (Br-BTHIQ, 1) and 1,2-demethyl-nuciferine (aporphine, 2), were herein synthesized, and their dopaminergic affinity in cloned human D2R, D3R, and D4R subtypes and their behavior as agonists/antagonists were evaluated. They showed affinity values (Ki) for hD2, hD3, and hD4 DR within the nanomolar range. The trends in affinity were hD4R ≫ hD3R > hD2R for Br-BTHIQ (1) and hD2R > hD4R > hD3R for 1,2-demethyl-nuciferine (2). The functional assays of cyclic adenosine monophosphate signaling at human D2R showed a partial agonist effect for Br-BTHIQ (1) and full agonist behavior for aporphine (2), with half maximal effective concentration values of 2.95 and 10.2 µM, respectively. Therefore, both isoquinolines 1 and 2 have emerged as lead molecules for the synthesis of new therapeutic drugs that ultimately may be useful to prevent schizophrenia and Parkinson's disease, respectively.

Synthesis of benzopyran derivatives as PPARα and/or PPARγ activators.

We describe the synthesis of 26 compounds, small polycerasoidol analogs, that are Lipinski's rule-of-five compliant. In order to confirm key structural features to activate PPARα and/or PPARγ, we have adopted structural modifications in the following parts: (i) the benzopyran core (hydrophobic nucleus) by benzopyran-4-one, dihydrobenzopyran or benzopyran-4-ol; (ii) the side chain at 2-position by shortening to C3, C4 and C5-carbons versus C-9-carbons of polycerasoidol; (iii) the carboxylic group (polar head) by oxygenated groups (hydroxyl, acetoxy, epoxide, ester, aldehyde) or non-oxygenated motifs (allyl and alkyl). Benzopyran-4-ones 6, 12, 13 and 17 as well as dihydrobenzopyrans 22, 24 and 25 were able to activate hPPARα, whereas benzopyran-4-one (7) with C5-carbons in the side chain exhibited hPPARγ agonism. According to our previous docking studies, SAR confirm that the hydrophobic nucleus (benzopyran-4-one or dihydrobenzopyran) is essential to activate PPARα and/or PPARγ, and the flexible linker (side alkyl chain) should containg at least C5-carbon atoms to activate PPARγ. By contrast, the polar head ("carboxylic group") tolerated several oxygenated groups but also non-oxygenated motifs. Taking into account these key structural features, small polycerasoidol analogs might provide potential active molecules useful in the treatment of dyslipidemia and/or type 2 diabetes.

Polycerasoidol, a Natural Prenylated Benzopyran with a Dual PPARα/PPARγ Agonist Activity and Anti-inflammatory Effect.

Dual peroxisome proliferator-activated receptor-α/γ (PPARα/γ) agonists regulate both lipid and glucose homeostasis under different metabolic conditions and can exert anti-inflammatory activity. We investigated the potential dual PPARα/γ agonism of prenylated benzopyrans polycerasoidol (1) and polycerasoidin (2) and their derivatives for novel drug development. Nine semisynthetic derivatives were prepared from the natural polycerasoidol (1) and polycerasoidin (2), which were evaluated for PPARα, -γ, -δ and retinoid X receptor-α activity in transactivation assays. Polycerasoidol (1) exhibited potent dual PPARα/γ agonism and low cytotoxicity. Structure-activity relationship studies revealed that a free phenol group at C-6 and a carboxylic acid at C-9' were key features for dual PPARα/γ agonism activity. Molecular modeling indicated the relevance of these groups for optimal ligand binding to the PPARα and PPARγ domains. In addition, polycerasoidol (1) exhibited a potent anti-inflammatory effect by inhibiting mononuclear leukocyte adhesion to the dysfunctional endothelium in a concentration-dependent manner via RXRα/PPARγ interactions. Therefore, polycerasoidol (1) can be considered a hit-to-lead molecule for the further development of novel dual PPARα/γ agonists capable of preventing cardiovascular events associated with metabolic disorders.

Upregulation of angiostatic chemokines IP-10/CXCL10 and I-TAC/CXCL11 in human obesity and their implication for adipose tissue angiogenesis.

BACKGROUND/AIMS: Impaired angiogenesis is linked to adipose tissue (AT) dysfunction, inflammation, and insulin resistance in human obesity. Chemokine (C-X-C motif) receptor. (CXCR3) ligands are important regulators of angiogenesis in different disease contexts such as cancer; however, their role in human morbid obesity is unknown. We investigated the role of the CXCR3 axis in AT angiogenesis in morbidly obese patients. SUBJECTS/METHODS: The study group comprised 50 morbidly obese patients (mean age 44 ± 1 years, body mass index 44 ± 1 kg/m2) who had undergone laparoscopic Roux-Y-gastric bypass surgery, and 25 age-matched non-obese control subjects. We measured the circulating levels of the CXCR3 ligands monokine induced by interferon-γ (MIG/CXCL9), interferon-γ inducible protein 10 (IP-10/CXCL10), and interferon-γ-inducible T-cell alpha chemoattractant (I-TAC/CXCL11) in all studied subjects. Additionally, the expression of CXCR3 ligands was analyzed in paired biopsies of subcutaneous and visceral AT obtained during the laparoscopic procedure in morbidly obese patients. Additionally, we explored the functional role of CXCR3 ligands on angiogenesis in AT from morbidly obese patients using an ex vivo assay. RESULTS: Plasma levels of CXCL10 and CXCL11 were significantly higher in morbidly obese patients than in controls (p < 0.01). In ex vivo assays, angiogenic growth was markedly lower in visceral AT than in subcutaneous AT (p < 0.05), which was related to significant tissue upregulation of CXCL10, CXCL11 and CXCR3 (p < 0.05). CXCL10 or CXCL11 inhibited AT angiogenesis (p < 0.05), and blockade of CXCR3 function significantly increased capillary sprouting in visceral fat deposits (p < 0.05). Western blot analysis showed that the p38 mitogen-activated protein kinase signaling pathway was implicated in the angiostatic effects of CXCR3 in AT. CONCLUSIONS: CXCL10 and CXCL11 may play. deleterious role in obesity as potential inhibitors of AT angiogenesis. Accordingly, pharmacological blockade of CXCR3 could represent. therapy to prevent AT dysfunction in obesity.

Neutrophil chemotaxis.

Neutrophils are the primary cells recruited to inflamed sites during an innate immune response to tissue damage and/or infection. They are finely sensitive to inciting stimuli to reach in great numbers and within minutes areas of inflammation and tissue insult. For this effective response, they can detect extracellular chemical gradients and move towards higher concentrations, the so-called chemotaxis process or guided cell migration. This directed neutrophil recruitment is orchestrated by chemoattractants, a chemically diverse group of molecular guidance cues (e.g., lipids, N-formylated peptides, complement, anaphylotoxins and chemokines). Neutrophils respond to these guidance signals in a hierarchical manner and, based on this concept, they can be further subdivided into two groups: "end target" and "intermediary" chemoattractants, the signals of the former dominant over the latter. Neutrophil chemoattractants exert their effects through interaction with heptahelical G protein-coupled receptors (GPCRs) expressed on cell surfaces and the chemotactic response is mainly regulated by the Rho family of GTPases. Additionally, neutrophil behavior might differ and be affected in different complex scenarios such as disease conditions and type of vascular bed in specific organs. Finally, there are different mechanisms to disrupt neutrophil chemotaxis either associated to the resolution of inflammation or to bacterial escape and systemic infection. Therefore, in the present review, we will discuss the different molecular players involved in neutrophil chemotaxis, paying special attention to the different chemoattractants described and the way that they interact intra- and extravascularly for neutrophils to properly reach the target tissue.