Concomitant NAFLD Facilitates Liver Metastases and PD-1-Refractory by Recruiting MDSCs via CXCL5/CXCR2 in Colorectal Cancer

BACKGROUND & AIMS

Both nonalcoholic fatty liver disease (NAFLD) and colorectal cancer (CRC) are prevalent worldwide. The effects of concomitant NAFLD on the risk of colorectal liver metastasis (CRLM) and its mechanisms have not been definitively elucidated.

METHODS

We observed the effect of concomitant NAFLD on CRLM in the mouse model and explored the underlying mechanisms of specific myeloid-derived suppressor cells (MDSCs) recruitment and then tested the therapeutic application based on the mechanisms. Finally we validated our findings in the clinical samples.

RESULTS

Here we prove that in different mouse models, NAFLD induces F4/80+ Kupffer cells to secret chemokine CXCL5 and then recruits CXCR2+ MDSCs to promote the growth of CRLM. CRLM with NAFLD background is refractory to the anti-PD-1 monoclonal antibody treatment, but when combined with Reparixin, an inhibitor of CXCR1/2, dual therapy cures the established CRLM in mice with NAFLD. Our clinical studies also indicate that fatty liver diseases increase the infiltration of CXCR2+ MDSCs, as well as the hazard of liver metastases in CRC patients.

CONCLUSIONS

Collectively, our findings highlight the significance of selective CXCR2+/CD11b+/Gr-1+ subset myeloid cells in favoring the development of CRLM with NAFLD background and identify a pharmaceutical medicine that is already available for the clinical trials and potential treatment.

Tissue-specific reprogramming leads to angiogenic neutrophil specialization and tumor vascularization in colorectal cancer

Neutrophil (PMN) tissue accumulation is an established feature of ulcerative colitis (UC) lesions and colorectal cancer (CRC). To assess the PMN phenotypic and functional diversification during the transition from inflammatory ulceration to CRC we analyzed the transcriptomic landscape of blood and tissue PMNs. Transcriptional programs effectively separated PMNs based on their proximity to peripheral blood, inflamed colon, and tumors. In silico pathway overrepresentation analysis, protein-network mapping, gene signature identification, and gene-ontology scoring revealed unique enrichment of angiogenic and vasculature development pathways in tumor-associated neutrophils (TANs). Functional studies utilizing ex vivo cultures, colitis-induced murine CRC, and patient-derived xenograft models demonstrated a critical role for TANs in promoting tumor vascularization. Spp1 (OPN) and Mmp14 (MT1-MMP) were identified by unbiased -omics and mechanistic studies to be highly induced in TANs, acting to critically regulate endothelial cell chemotaxis and branching. TCGA data set and clinical specimens confirmed enrichment of SPP1 and MMP14 in high-grade CRC but not in patients with UC. Pharmacological inhibition of TAN trafficking or MMP14 activity effectively reduced tumor vascular density, leading to CRC regression. Our findings demonstrate a niche-directed PMN functional specialization and identify TAN contributions to tumor vascularization, delineating what we believe to be a new therapeutic framework for CRC treatment focused on TAN angiogenic properties.

Effects of β-Glucan Supplementation on LPS-Induced Endotoxemia in Horses

β-glucan is part of the cell wall of fungi and yeasts and has been known for decades to have immunomodulating effects on boosting immunity against various infections as a pathogen-associated molecular pattern that is able to modify biological responses. β-glucan has been used in rat models and in vitro studies involving sepsis and SIRS with good results, but this supplement has not been evaluated in the treatment of endotoxemia in horses. This study aims to evaluate the effects of preventive supplementation with β-glucan in horses submitted to endotoxemia by means of inflammatory response modulation. Eight healthy horses, both male and female, aged 18 ± 3 months, weighing 300 ± 100 kg of mixed breed, were randomly assigned to two groups of four animals, both of which were subjected to the induction of endotoxemia via the intravenous administration of E. coli lipopolysaccharides (0.1 µg/kg). For 30 days before the induction of endotoxemia, horses in the β-glucan group (GB) received 10 mg/kg/day of β-glucan orally, and horses in the control group (GC) received 10 mg/kg/day of 0.9% sodium chloride orally. The horses were submitted to physical exams, including a hematological, serum biochemistry, and peritoneal fluid evaluation, and the serum quantification of cytokines TNF-α, IL-6, IL-8, and IL-10. For statistical analysis, the normality of residues and homogeneity of variances were verified; then, the variables were analyzed as repeated measures over time, checking the effect of treatment, time, and the interaction between time and treatment. Finally, the averages were compared using Tukey's test at a significance level of 5%. Horses from both experimental groups presented clinical signs and hematological changes in endotoxemia, including an increase in heart rate and body temperature, neutrophilic leukopenia, an increase in serum bilirubin, glucose, lactate, and an increase in TNF-α, IL-6, and IL-10. Hepatic and renal function were not compromised by β-glucan supplementation. GB presented higher mean values of the serum total protein, globulins, and IL-8 compared to that observed in GC. In the peritoneal fluid, horses from GB presented a lower mean concentration of neutrophils and a higher mean concentration of macrophages compared to the GC. It was concluded that preventive supplementation of β-glucan for thirty days modulated the immune response, as evidenced by increasing serum total proteins, globulins, IL-8, and changes in the type of peritoneal inflammatory cells, without effectively attenuating clinical signs of endotoxemia in horses. Considering the safety of β-glucan in this study, the results suggest the potential clinical implication of β-glucan for prophylactic use in horse endotoxemia.

Allosteric Regulation of G-Protein-Coupled Receptors: From Diversity of Molecular Mechanisms to Multiple Allosteric Sites and Their Ligands

Allosteric regulation is critical for the functioning of G protein-coupled receptors (GPCRs) and their signaling pathways. Endogenous allosteric regulators of GPCRs are simple ions, various biomolecules, and protein components of GPCR signaling (G proteins and β-arrestins). The stability and functional activity of GPCR complexes is also due to multicenter allosteric interactions between protomers. The complexity of allosteric effects caused by numerous regulators differing in structure, availability, and mechanisms of action predetermines the multiplicity and different topology of allosteric sites in GPCRs. These sites can be localized in extracellular loops; inside the transmembrane tunnel and in its upper and lower vestibules; in cytoplasmic loops; and on the outer, membrane-contacting surface of the transmembrane domain. They are involved in the regulation of basal and orthosteric agonist-stimulated receptor activity, biased agonism, GPCR-complex formation, and endocytosis. They are targets for a large number of synthetic allosteric regulators and modulators, including those constructed using molecular docking. The review is devoted to the principles and mechanisms of GPCRs allosteric regulation, the multiplicity of allosteric sites and their topology, and the endogenous and synthetic allosteric regulators, including autoantibodies and pepducins. The allosteric regulation of chemokine receptors, proteinase-activated receptors, thyroid-stimulating and luteinizing hormone receptors, and beta-adrenergic receptors are described in more detail.

Obesity, inflammation, and cancer in dogs: Review and perspectives

Obesity is the most common nutritional disease in dogs, and its prevalence has increased in recent decades. Several countries have demonstrated a prevalence of obesity in dogs similar to that observed in humans. Chronic low-grade inflammation is a prominent basis used to explain how obesity results in numerous negative health consequences. This is well known and understood, and recent studies have pointed to the association between obesity and predisposition to specific types of cancers and their complications. Such elucidations are important because, like obesity, the prevalence of cancer in dogs has increased in recent decades, establishing cancer as a significant cause of death for these animals. In the same way, intensive advances in technology in the field of human and veterinary medicine (which even proposes the use of animal models) have optimized existing therapeutic methods, led to the development of innovative treatments, and shortened the time to diagnosis of cancer. Despite the great challenges, this review aims to highlight the evidence obtained to date on the association between obesity, inflammation, and cancer in dogs, and the possible pathophysiological mechanisms that link obesity and carcinogenesis. The potential to control cancer in animals using existing knowledge is also presented.

Tumor cells educate mesenchymal stromal cells to release chemoprotective and immunomodulatory factors

Factors released by surrounding cells such as cancer-associated mesenchymal stromal cells (CA-MSCs) are involved in tumor progression and chemoresistance. In this study, we characterize the mechanisms by which naïve mesenchymal stromal cells (MSCs) can acquire a CA-MSCs phenotype. Ovarian tumor cells trigger the transformation of MSCs to CA-MSCs by expressing pro-tumoral genes implicated in the chemoresistance of cancer cells, resulting in the secretion of high levels of CXC chemokine receptors 1 and 2 (CXCR1/2) ligands such as chemokine (C-X-C motif) ligand 1 (CXCL1), CXCL2, and interleukin 8 (IL-8). CXCR1/2 ligands can also inhibit the immune response against ovarian tumor cells. Indeed, through their released factors, CA-MSCs promote the differentiation of monocytes towards M2 macrophages, which favors tumor progression. When CXCR1/2 receptors are inhibited, these CA-MSC-activated macrophages lose their M2 properties and acquire an anti-tumoral phenotype. Both ex vivo and in vivo, we used a CXCR1/2 inhibitor to sensitize ovarian tumor cells to carboplatin and circumvent the pro-tumoral effects of CA-MSCs. Since high concentrations of CXCR1/2 ligands in patients’ blood are associated with chemoresistance, CXCR1/2 inhibition could be a potential therapeutic strategy to revert carboplatin resistance.

Sulfatase 1 mediates IL-10-induced dimethylarginine dimethylaminohydrolase-1 expression and antiproliferative effects in vascular smooth muscle cells of spontaneously hypertensive rats

The extracellular sulfatases (exSulfs) sulfatase 1 (Sulf1) and sulfatase 2 (Sulf2) are well-known regulators of cell signaling and metabolism. In addition, exSulfs mediate the up- or downregulatory effects of cytokines on angiotensin II (Ang II)-induced expression of hypertensive mediators in vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHRs). Previously, we demonstrated that interleukin-10 (IL-10)-induced dimethylarginine dimethylaminohydrolase-1 (DDAH-1) expression was mediated by Ang II subtype 2 receptor (AT2 R) and AMP-activated protein kinase (AMPK) activation, and that IL-10-mediated inhibition of Ang II-induced proliferation of SHRs VSMC was partially associated with DDAH-1. In this study, we examined the effects of exSulfs on IL-10-induced DDAH-1 expression, abrogation of Ang II-induced DDAH-1 downregulation, and inhibition of Ang II-induced proliferation of SHRs VSMC. IL-10-induced DDAH-1 expression and abrogation of Ang II-induced DDAH-1 downregulation were attenuated in Sulf1 siRNA-transfected SHRs VSMC. However, Sulf2 did not affect IL-10-induced DDAH-1 expression and abrogation of Ang II-induced DDAH-1 downregulation. Downregulation of Sulf1 inhibited IL-10-induced AT2 R expression and the synergistic effects of IL-10 on Ang II-induced AT2 R expression. Additionally, Sulf1 downregulation inhibited IL-10-induced AMPK activity and abrogation of Ang II-induced decrease in AMPK activity. Moreover, the IL-10-mediated inhibition of Ang II-induced proliferation was not detected in Sulf1 siRNA-transfected SHRs VSMC; IL-10-mediated inhibition of Ang II-induced VSMC proliferation was mediated via the AT2 R pathway and AMPK activation. Specifically, IL-10-induced DDAH-1 expression, abrogation of Ang II-induced DDAH-1 downregulation, and inhibition of Ang II-induced proliferation, which is mediated by the AT2 R pathway and AMPK activation, are mainly mediated by Sulf1 activity in SHRs VSMC. These results suggest that Sulf1, and not Sulf2, mediates the IL-10-induced inhibition of Ang II-induced hypertensive effects in SHRs VSMC.

Role of inflammatory chemokines in hypertension

Hypertension is associated with immune cells activation and their migration into the kidney, vasculature, heart and brain. These inflammatory mechanisms are critical for blood pressure regulation and mediate target organ damage, creating unique novel targets for pharmacological modulation. In response to angiotensin II and other pro-hypertensive stimuli, the expression of several inflammatory chemokines and their receptors is increased in the target organs, mediating homing of immune cells. In this review, we summarize the contribution of key inflammatory chemokines and their receptors to increased accumulation of immune cells in target organs and effects on vascular dysfunction, remodeling, oxidative stress and fibrosis, all of which contribute to blood pressure elevation. In particular, the role of CCL2, CCL5, CXCL8, CXCL9, CXCL10, CXCL11, CXCL16, CXCL1, CX3CL1, XCL1 and their receptors in the context of hypertension is discussed. Recent studies have tested the efficacy of pharmacological or genetic targeting of chemokines and their receptors on the development of hypertension. Promising results indicate that some of these pathways may serve as future therapeutic targets to improve blood pressure control and prevent target organ consequences including kidney failure, heart failure, atherosclerosis or cognitive impairment.

Biased agonism at chemokine receptors

In the human chemokine system, interactions between the approximately 50 known endogenous chemokine ligands and 20 known chemokine receptors (CKRs) regulate a wide range of cellular functions and biological processes including immune cell activation and homeostasis, development, angiogenesis, and neuromodulation. CKRs are a family of G protein-coupled receptors (GPCR), which represent the most common and versatile class of receptors in the human genome and the targets of approximately one third of all Food and Drug Administration-approved drugs. Chemokines and CKRs bind with significant promiscuity, as most CKRs can be activated by multiple chemokines and most chemokines can activate multiple CKRs. While these ligand-receptor interactions were previously regarded as redundant, it is now appreciated that many chemokine:CKR interactions display biased agonism, the phenomenon in which different ligands binding to the same receptor signal through different pathways with different efficacies, leading to distinct biological effects. Notably, these biased responses can be modulated through changes in ligand, receptor, and or the specific cellular context (system). In this review, we explore the biochemical mechanisms, functional consequences, and therapeutic potential of biased agonism in the chemokine system. An enhanced understanding of biased agonism in the chemokine system may prove transformative in the understanding of the mechanisms and consequences of biased signaling across all GPCR subtypes and aid in the development of biased pharmaceuticals with increased therapeutic efficacy and safer side effect profiles.

Chemokine Receptor CXCR-2 Initiates Atrial Fibrillation by Triggering Monocyte Mobilization in Mice

Atrial fibrillation (AF) is frequently associated with increased inflammatory response characterized by infiltration of monocytes/macrophages. The chemokine receptor CXCR-2 is a critical regulator of monocyte mobilization in hypertension and cardiac remodeling, but it is not known whether CXCR-2 is involved in the development of hypertensive AF. AF was induced by infusion of Ang II (angiotensin II; 2000 ng/kg per minute) for 3 weeks in male C57BL/6 wild-type mice, CXCR-2 knockout mice, bone marrow-reconstituted chimeric mice, and mice treated with the CXCR-2 inhibitor SB225002. Microarray analysis revealed that 4 chemokine ligands of CXCR-2 were significantly upregulated in the atria during 3 weeks of Ang II infusion. CXCR-2 expression and the number of CXCR2⁺ immune cells markedly increased in Ang II-infused atria in a time-dependent manner. Moreover, Ang II-infused wild-type mice had increased blood pressure, AF inducibility, atrial diameter, fibrosis, infiltration of macrophages, and superoxide production compared with saline-treated wild-type mice, whereas these effects were significantly attenuated in CXCR-2 knockout mice and wild-type mice transplanted with CXCR-2-deficient bone marrow cells or treated with SB225002. Moreover, circulating blood CXCL-1 levels and CXCR2⁺ monocyte counts were higher and associated with AF in human patients (n=31) compared with sinus rhythm controls (n=31). In summary, this study identified a novel role for CXCR-2 in driving monocyte infiltration of the atria, which accelerates atrial remodeling and AF after hypertension. Blocking CXCR-2 activation may serve as a new therapeutic strategy for AF.

Human Naive T Cells Express Functional CXCL8 and Promote Tumorigenesis

Naive T cells are thought to be functionally quiescent. In this study, we studied and compared the phenotype, cytokine profile, and potential function of human naive CD4+ T cells in umbilical cord and peripheral blood. We found that naive CD4+ T cells, but not memory T cells, expressed high levels of chemokine CXCL8. CXCL8+ naive T cells were preferentially enriched CD31+ T cells and did not express T cell activation markers or typical Th effector cytokines, including IFN-γ, IL-4, IL-17, and IL-22. In addition, upon activation, naive T cells retained high levels of CXCL8 expression. Furthermore, we showed that naive T cell-derived CXCL8 mediated neutrophil migration in the in vitro migration assay, supported tumor sphere formation, and promoted tumor growth in an in vivo human xenograft model. Thus, human naive T cells are phenotypically and functionally heterogeneous and can carry out active functions in immune responses.

A Phase I study of the novel immunomodulatory agent PG545 (pixatimod) in subjects with advanced solid tumours

Background

PG545 (pixatimod) is a novel immunomodulatory agent, which has been demonstrated to stimulate innate immune responses against tumours in preclinical cancer models.

Methods

This Phase I study investigated the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary efficacy of PG545 monotherapy. Escalating doses of PG545 were administered to patients with advanced solid malignancies as a weekly 1-h intravenous infusion.

Results

Twenty-three subjects were enrolled across four cohorts (25, 50, 100 and 150 mg). Three dose-limiting toxicities (DLTs)—hypertension (2), epistaxis (1)—occurred in the 150 mg cohort. No DLTs were noted in the 100 mg cohort, which was identified as the maximum-tolerated dose. No objective responses were reported. Best response was stable disease up to 24 weeks, with the disease control rate in evaluable subjects of 38%. Exposure was proportional up to 100 mg and mean half-life was 141 h. The pharmacodynamic data revealed increases in innate immune cell activation, plasma IFNγ, TNFα, IP-10 and MCP-1.

Conclusion

PG545 demonstrated a tolerable safety profile, proportional PK, evidence of immune cell stimulation and disease control in some subjects. Taken together, these data support the proposed mechanism of action, which represents a promising approach for use in combination with existing therapies.

Effects of S-1-propenylcysteine, a sulfur compound in aged garlic extract, on blood pressure and peripheral circulation in spontaneously hypertensive rats

OBJECTIVES

This study was designed to investigate the antihypertensive effect of S-1-propenylcysteine, a characteristic sulfur compound in aged garlic extract, using a hypertensive rat model.

METHODS

The blood pressure and tail blood flow of both spontaneously hypertensive rats and control Wistar Kyoto rats were measured by the tail-cuff method and the noncontact laser Doppler method, respectively, at various times after single oral administration of a test compound for 24 h.

KEY FINDINGS

Treatment with S-1-propenylcysteine (6.5 mg/kg BW) significantly decreased the systolic blood pressure of spontaneously hypertensive rat approximately 10% at 3 h after administration, and thereafter, the systolic blood pressure gradually returned to the baseline level in 24 h. The effect of S-1-propenylcysteine was dose-dependent and was maximal at the dose of 6.5 mg/kg BW at 3 h. However, the other compounds such as S-allylcysteine and S-allylmercaptocysteine in aged garlic extract were ineffective. In addition, S-1-propenylcysteine had no effect on systolic blood pressure of control Wistar Kyoto rats. Furthermore, S-1-propenylcysteine significantly increased the blood flow at 3 h after administration at the dose of 6.5 mg/kg BW.

CONCLUSIONS

S-1-propenylcysteine is a key constituent of aged garlic extract responsible for its antihypertensive effect, and the effect of S-1-propenylcysteine involves the improvement in peripheral circulation.

Crosstalk between stromal components and tumor cells of TNBC via secreted factors enhances tumor growth and metastasis

Triple negative breast cancer (TNBC) as a metastatic disease is currently incurable. Reliable and reproducible methods for testing drugs against metastasis are not available. Stromal cells may play a critical role in tumor progression and metastasis. In this study, we determined that fibroblasts and macrophages secreted IL-8 upon induction by tumor cell-conditioned media (TCM) from MDA-MB-231 cancer cells. Our data showed that the proliferation of MDA-MB-231 cells co-cultured with fibroblasts or macrophages was enhanced compared to the monoculture. Furthermore, TNBC cell migration, a key step in tumor metastasis, was promoted by conditioned media (CM) from TCM-induced fibroblasts or macrophages. Knockdown of the IL-8 receptor CXCR2 by CRISPR-Cas9 reduces MDA-MB-231 cell proliferation and migration compared to wild type. In a mouse xenograft tumor model, the growth of MDA-MB-231-CXCR2^−/− tumor was significantly decreased compared to the growth of tumors from wild-type cells. In addition, the incidence of thoracic metastasis of MDA-MB-231-CXCR2^−/− tumors was reduced compared to wild type. We found that the auto- and paracrine loop exists between TNBC cells and stroma, which results in enhanced IL-8 secretion from the stromal components. Significantly, inhibition of the IL-8 signaling pathway by reparixin, an inhibitor of the IL-8 receptor, CXCR1/2, reduced MDA-MB-231 tumor growth and metastasis. Taken together, these findings implicate IL-8 signaling as a critical event in TNBC tumor growth and metastasis via crosstalk with stromal components.

Genetic and Pharmacologic Inhibition of the Chemokine Receptor CXCR2 Prevents Experimental Hypertension and Vascular Dysfunction

Supplemental Digital Content is available in the text.

Background:

The recruitment of leukocytes to the vascular wall is a key step in hypertension development. Chemokine receptor CXCR2 mediates inflammatory cell chemotaxis in several diseases. However, the role of CXCR2 in hypertension development and the underlying mechanisms remain unknown.

Methods:

Angiotensin II (490 ng·kg^-1·min^-1) or deoxycorticosterone acetate (DOCA) salt–induced mouse hypertensive models in genetic ablation, pharmacologic inhibition of CXCR2, and adoptive bone marrow transfer mice were used to determine the role of CXCR2 in hypertension (measured by radiotelemetry and tail-cuff system), inflammation (verified by flow cytometry and quantitative real-time polymerase chain reaction [PCR] analysis), vascular remodeling (studied by haematoxylin and eosin and Masson’s trichrome staining), vascular dysfunction (assessed by aortic ring), and oxidative stress (indicated by nicotinamide adenine dinucleotide phosphate [NADPH] oxidase activity, dihydroethidium staining, and quantitative real-time PCR analysis). Moreover, the blood CXCR2⁺ cells in normotensive controls and hypertension patients were analyzed by flow cytometry.

Results:

Angiotensin II significantly upregulated the expression of CXCR2 mRNA and protein and increased the number of CD45⁺ CXCR2⁺ cells in mouse aorta (n=8 per group). Selective CXCR2 knockout (CXCR2^-/-) or pharmacological inhibition of CXCR2 markedly reduced angiotensin II- or DOCA-salt-induced blood pressure elevation, aortic thickness and collagen deposition, accumulation of proinflammatory cells into the vascular wall, and expression of cytokines (n=8 per group). CXCR2 inhibition also ameliorated angiotensin II-induced vascular dysfunction and reduced vascular superoxide formation, NADPH activity, and expression of NADPH oxidase subunits (n=6 per group). Bone marrow reconstitution of wild-type mice with CXCR2^-/- bone marrow cells also significantly abolished angiotensin II-induced responses (n=6 per group). It is important to note that CXCR2 blockade reversed established hypertension induced by angiotensin II or DOCA-salt challenge (n=10 per group). Furthermore, we demonstrated that CXCR2⁺ proinflammatory cells were higher in hypertensive patients (n=30) compared with normotensive individuals (n=20).

Conclusions:

Infiltration of CXCR2⁺ cells plays a pathogenic role in arterial hypertension and vascular dysfunction. Inhibition of CXCR2 pathway may represent a novel therapeutic approach to treat hypertension.

Effect of olive oil phenolic compounds on the expression of blood pressure-related genes in healthy individuals

PURPOSE

To investigate whether the ingestion of olive oil having different phenolic contents influences the expression of blood pressure-related genes, involved in the renin-angiotensin-aldosterone system, in healthy humans.

METHODS

A randomized, double-blind, crossover human trial with 18 healthy subjects, who ingested 25 mL/day of olive oils (1) high (366 mg/kg, HPC) and (2) low (2.7 mg/kg, LPC) in phenolic compounds for 3 weeks, preceded by 2-week washout periods. Determination of selected blood pressure-related gene expression in peripheral blood mononuclear cells (PBMNC) by qPCR, blood pressure and systemic biomarkers.

RESULTS

HPC decreased systolic blood pressure compared to pre-intervention values and to LPC, and maintained diastolic blood pressure values compared to LPC. HPC decreased ACE and NR1H2 gene expressions compared with pre-intervention values, and IL8RA gene expression compared with LPC.

CONCLUSIONS

The introduction to the diet of an extra-virgin olive oil rich in phenolic compounds modulates the expression of some of the genes related to the renin-angiotensin-aldosterone system. These changes could underlie the decrease in systolic blood pressure observed.

CCL5 upregulates IL-10 expression and partially mediates the antihypertensive effects of IL-10 in the vascular smooth muscle cells of spontaneously hypertensive rats

Interleukin (IL)-10 inhibits angiotensin (Ang) II-induced vascular dysfunction and reduces blood pressure in hypertensive pregnant rats. The chemokine CCL5 has also been shown to downregulate Ang II-induced hypertensive mediators in spontaneously hypertensive rats (SHRs). This study investigated the effects of CCL5 on IL-10 expression, as well as its mechanisms of action in the vascular smooth muscle cells (VSMCs) of SHRs. CCL5 increased IL-10 expression in the VSMCs of SHRs; the s.c. injection of CCL5 (1.5 μg kg(-1), twice a day) for 3 weeks into SHRs with established hypertension upregulated IL-10 expression in both the thoracic aorta and the VSMCs and decreased systolic blood pressure. CCL5-induced the elevation of IL-10 expression, an effect mediated primarily via the activation of an Ang II subtype II receptor (AT2 R). Dimethylarginine dimethylaminohydrolase (DDAH)-1 activity also contributed to the elevation of IL-10 expression via CCL5 in the VSMCs of SHRs. Moreover, CCL5 partially mediated the inhibitory effects of IL-10 on Ang II-induced 12-lipoxygenase (LO) and endothelin (ET)-1 expression in the VSMCs of SHRs. Taken together, this study provides novel evidence that CCL5 plays a role in the upregulation of IL-10 activity in the VSMCs of SHRs.

Avaliação clínica e hematológica de equinos submetidos ao modelo de laminite por oligofructose, tratados ou não com um agente antagonista de receptores CXCR1/2

O recrutamento de leucócitos aos tecidos é uma parte essencial da resposta imune inata e esse processo de forma desregulada pode resultar em lesões aos tecidos. Assim, a infiltração de leucócitos tem sido implicada na patogênese de laminite aguda em equinos. Os objetivos dessa pesquisa foram verificar a ação da ICXCR1/2 sobre os sinais clínicos e parâmetros hematológicos de cavalos com laminite induzida por oligofrutose. Doze equinos receberam oligofrutose (10g/kg de peso vivo PO) no tempo 0 e foram divididos em 2 grupos: tratados (30mg/kg p.v. ICXCR1/2 IV, nos tempos 6, 12, 18 e 24 h) e não tratados. As frequências cardíaca e respiratória, temperatura retal, coloração de membranas mucosas, presença e intensidade de pulso digital, sensibilidade ao exame com pinça de casco e grau de claudicação segundo Obel, bem como parâmetros hematológicos e bioquímicos (hemograma e as concentrações sanguíneas de glicose, uréia, creatinina, ALT, AST, FA, GGT, bilirrubina total e proteína total) foram aferidos nos tempos 0, 6, 12, 18, 24, 36, 48, 60 e 72 horas . O modelo usando oligofructose foi adequado para induzir sinais de laminite e de sinais de endotoxemia, como diarreia, febre e leucocitose em cavalos sem raça definida de origem nacional. Também, não foram observadas quaisquer reações adversas clínicas ou hematológicas relacionadas ao uso intravenoso do antagonista de CXCR1/2, contudo essa substância, quando administrada na dose de 30mg/kg de peso vivo, 4 vezes ao dia, por 4 aplicações, não foi capaz de prevenir os sinais clínicos e as alterações hematológicas causadas pela administração de oligofructose nos equinos deste estudo.