The Novel Small-molecule Annexin-A1 Mimetic, Compound 17b, Elicits Vasoprotective Actions in Streptozotocin-induced Diabetic Mice

Therapeutic potential of relaxin or relaxin mimetics in managing cardiovascular complications of diabetes

Diabetes mellitus is a metabolic disease with an escalating global prevalence. Despite the abundance and relative efficacies of current therapeutic approaches, they primarily focus on attaining the intended glycaemic targets, but patients ultimately still suffer from various diabetes-associated complications such as retinopathy, nephropathy, cardiomyopathy, and atherosclerosis. There is a need to explore innovative and effective diabetic treatment strategies that not only address the condition itself but also combat its complications. One promising option is the reproductive hormone relaxin, an endogenous ligand of the RXFP1 receptor. Relaxin is known to exert beneficial actions on the cardiovascular system through its vasoprotective, anti-inflammatory and anti-fibrotic effects. Nevertheless, the native relaxin peptide exhibits a short biological half-life, limiting its therapeutic potential. Recently, several relaxin mimetics and innovative delivery technologies have been developed to extend its biological half-life and efficacy. The current review provides a comprehensive landscape of the cardiovascular effects of relaxin, focusing on its potential therapeutic applications in managing complications associated with diabetes. The latest advancements in the development of relaxin mimetics and delivery methods for the treatment of cardiometabolic disorders are also discussed.

Formyl peptide receptor 1 mitigates colon inflammation and maintains mucosal homeostasis through the inhibition of CREB-C/EBPβ-S100a8 signaling

Excessive inflammatory responses are the main characteristic of ulcerative colitis (UC). Activation of formyl peptide receptor 1 (FPR1) has been found to promote the proliferation and migration of epithelial cells, but its role and therapeutic potential in UC remain unclear. This study observed an increased expression of FPR1 in a mouse model of colitis. Interestingly, FPR1 deficiency exacerbated UC and increased the secretion of the proinflammatory mediator from immune cells (e.g. macrophages), S100a8, a member of the damage-associated molecular patterns. Notably, the administration of the FPR agonist Cmpd43 ameliorated colon injury in a preclinical mice model of UC, likely via inhibiting phosphorylation of cyclic adenosine monophosphate-response element-binding protein and expression of CCAAT/enhancer-binding protein β, which in turn suppressed the secretion of S100a8. In conclusion, these findings discovered a novel role of FPR1 in the development of colitis and will facilitate the development of FPR1-based pharmacotherapy to treat UC.

The small-molecule formyl peptide receptor biased agonist, compound 17b, is a vasodilator and anti-inflammatory in mouse precision-cut lung slices

BACKGROUND AND PURPOSE

Pulmonary arterial hypertension (PAH), a rare fatal disorder characterised by inflammation, vascular remodelling and vasoconstriction. Current vasodilator therapies reduce pulmonary arterial pressure but not mortality. The G-protein coupled formyl peptide receptors (FPRs) mediates vasodilatation and resolution of inflammation, actions possibly beneficial in PAH. We investigated dilator and anti-inflammatory effects of the FPR biased agonist compound 17b in pulmonary vasculature using mouse precision-cut lung slices (PCLS).

EXPERIMENTAL APPROACH

PCLS from 8-week-old male and female C57BL/6 mice, intrapulmonary arteries were pre-contracted with 5-HT for concentration-response curves to compound 17b and 43, and standard-of-care drugs, sildenafil, iloprost and riociguat. Compound 17b-mediated relaxation was assessed with FPR antagonists or inhibitors and in PCLS treated with TNF-α or LPS. Cytokine release from TNF-α- or LPS-treated PCLS ± compound 17b was measured.

KEY RESULTS

Compound 17b elicited concentration-dependent vasodilation, with potencies of iloprost > compound 17b = riociguat > compound 43 = sildenafil. Compound 17b was inhibited by the FPR1 antagonist cyclosporin H but not by soluble guanylate cyclase, nitric oxide synthase or cyclooxygenase inhibitors. Under inflammatory conditions, the efficacy and potency of compound 17b were maintained, while iloprost and sildenafil were less effective. Additionally, compound 17b inhibited secretion of PAH-relevant cytokines via FPR2.

CONCLUSIONS AND IMPLICATIONS

Vasodilation to compound 17b but not standard-of-care vasodilators, is maintained under inflammatory conditions, with additional inhibition of PAH-relevant cytokine release. This provides the first evidence that targeting FPR, with biased agonist, simultaneously targets vascular function and inflammation, supporting the development of FPR-based pharmacotherapy to treat PAH.

LINKED ARTICLES

This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.

Novel formylpeptide receptor 1/2 agonist limits hypertension-induced cardiovascular damage

AIMS

Formylpeptide receptors (FPRs) play a critical role in the regulation of inflammation, an important driver of hypertension-induced end-organ damage. We have previously reported that the biased FPR small-molecule agonist, compound17b (Cmpd17b), is cardioprotective against acute, severe inflammatory insults. Here, we reveal the first compelling evidence of the therapeutic potential of this novel FPR agonist against a longer-term, sustained inflammatory insult, i.e. hypertension-induced end-organ damage. The parallels between the murine and human hypertensive proteome were also investigated.

METHODS AND RESULTS

The hypertensive response to angiotensin II (Ang II, 0.7 mg/kg/day, s.c.) was attenuated by Cmpd17b (50 mg/kg/day, i.p.). Impairments in cardiac and vascular function assessed via echocardiography were improved by Cmpd17b in hypertensive mice. This functional improvement was accompanied by reduced cardiac and aortic fibrosis and vascular calcification. Cmpd17b also attenuated Ang II-induced increased cardiac mitochondrial complex 2 respiration. Proteomic profiling of cardiac and aortic tissues and cells, using label-free nano-liquid chromatography with high-sensitivity mass spectrometry, detected and quantified ∼6000 proteins. We report hypertension-impacted protein clusters associated with dysregulation of inflammatory, mitochondrial, and calcium responses, as well as modified networks associated with cardiovascular remodelling, contractility, and structural/cytoskeletal organization. Cmpd17b attenuated hypertension-induced dysregulation of multiple proteins in mice, and of these, ∼110 proteins were identified as similarly dysregulated in humans suffering from adverse aortic remodelling and cardiac hypertrophy.

CONCLUSION

We have demonstrated, for the first time, that the FPR agonist Cmpd17b powerfully limits hypertension-induced end-organ damage, consistent with proteome networks, supporting development of pro-resolution FPR-based therapeutics for treatment of systemic hypertension complications.

Estrogenic endocrine disruptor exposure directly impacts erectile function

Erectile dysfunction (ED) is an extremely prevalent condition which significantly impacts quality of life. The rapid increase of ED in recent decades suggests the existence of unidentified environmental risk factors contributing to this condition. Endocrine Disrupting Chemicals (EDCs) are one likely candidate, given that development and function of the erectile tissues are hormonally dependent. We use the estrogenic-EDC diethylstilbestrol (DES) to model how widespread estrogenic-EDC exposure may impact erectile function in humans. Here we show that male mice chronically exposed to DES exhibit abnormal contractility of the erectile tissue, indicative of ED. The treatment did not affect systemic testosterone production yet significantly increased estrogen receptor α (Esr1) expression in the primary erectile tissue, suggesting EDCs directly impact erectile function. In response, we isolated the erectile tissue from mice and briefly incubated them with the estrogenic-EDCs DES or genistein (a phytoestrogen). These acute-direct exposures similarly caused a significant reduction in erectile tissue contractility, again indicative of ED. Overall, these findings demonstrate a direct link between estrogenic EDCs and erectile dysfunction and show that both chronic and acute estrogenic exposures are likely risk factors for this condition.

Time-dependent specific molecular signatures of inflammation and remodelling are associated with trimethylamine-N-oxide (TMAO)-induced endothelial cell dysfunction

Endothelial dysfunction is a critical initiating factor contributing to cardiovascular diseases, involving the gut microbiome-derived metabolite trimethylamine N-oxide (TMAO). This study aims to clarify the time-dependent molecular pathways by which TMAO mediates endothelial dysfunction through transcriptomics and metabolomics analyses in human microvascular endothelial cells (HMEC-1). Cell viability and reactive oxygen species (ROS) generation were also evaluated. TMAO treatment for either 24H or 48H induces reduced cell viability and enhanced oxidative stress. Interestingly, the molecular signatures were distinct between the two time-points. Specifically, few Gene Ontology biological processes (BPs) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were modulated after a short (24H) compared to a long (48H) treatment. However, the KEGG signalling pathways namely "tumour necrosis factor (TNF)" and "cytokine-cytokine receptor interaction" were downregulated at 24H but activated at 48H. In addition, at 48H, BPs linked to inflammatory phenotypes were activated (confirming KEGG results), while BPs linked to extracellular matrix (ECM) structural organisation, endothelial cell proliferation, and collagen metabolism were repressed. Lastly, metabolic profiling showed that arachidonic acid, prostaglandins, and palmitic acid were enriched at 48H. This study demonstrates that TMAO induces distinct time-dependent molecular signatures involving inflammation and remodelling pathways, while pathways such as oxidative stress are also modulated, but in a non-time-dependent manner.

Recent advances in the combination of organic solvent-free extraction, chemical standardization, antioxidant assay, and cell culture metabolomics for functional food and its by-product

Functional foods and their by-products contain a wide range of bioactive components with an array of health benefits and were proposed to improve public health, well-being, and others. To achieve a circular economy, the processing and extraction of flavonoids, phenolic compounds, and others from functional food and agri-food wastes will require the use of environmentally friendly, sustainable, and a low-cost solution. Extraction methods that can eliminate the use of organic solvents, suitable for use in the laboratory and production of extracts will be covered. This will include subcritical water extraction (SBE), pressurized hot water extraction (PHWE), supercritical fluid extraction (SFE), and others. Based on the selected analytical methods, the determination of the marker or bioactive compounds and chemical fingerprints will provide the control measures to identify the batch-to-batch variation of the composition of the functional food products obtained. The combination of chemical standardization with antioxidant assay, such as DPPH and ABTS+ will provide further information on the quality of the extracts. Lastly, to ascertain the biological and physiological relevance of the antioxidant properties of the target sample, treatment of the antioxidant compounds or extracts was carried out using cellular models, and validated using other experimental endpoints, such as metabolomics.

Relaxin elicits renoprotective actions accompanied by increasing bile acid levels in streptozotocin-induced diabetic mice

BACKGROUND

The peptide hormone relaxin has potent anti-fibrotic and anti-inflammatory properties in various organs, including the kidneys. However, the protective effects of relaxin in the context of diabetic kidney complications remain controversial. Here, we aimed to evaluate the effects of relaxin treatment on key markers of kidney fibrosis, oxidative stress, and inflammation and their subsequent impact on bile acid metabolism in the streptozotocin-induced diabetes mouse model.

METHODS AND RESULTS

Male mice were randomly allocated to placebo-treated control, placebo-treated diabetes or relaxin-treated diabetes groups (0.5 mg/kg/d, final 2 weeks of diabetes). After 12 weeks of diabetes or sham, the kidney cortex was harvested for metabolomic and gene expression analyses. Diabetic mice exhibited significant hyperglycaemia and increased circulating levels of creatine, hypoxanthine and trimethylamine N-oxide in the plasma. This was accompanied by increased expression of key markers of oxidative stress (Txnip), inflammation (Ccl2 and Il6) and fibrosis (Col1a1, Mmp2 and Fn1) in the diabetic kidney cortex. Relaxin treatment for the final 2 weeks of diabetes significantly reduced these key markers of renal fibrosis, inflammation, and oxidative stress in diabetic mice. Furthermore, relaxin treatment significantly increased the levels of bile acid metabolites, deoxycholic acid and sodium glycodeoxycholic acid, which may in part contribute to the renoprotective action of relaxin in diabetes.

CONCLUSION

In summary, this study shows the therapeutic potential of relaxin and that it may be used as an adjunctive treatment for diabetic kidney complications.

Gut-Derived Metabolite, Trimethylamine-N-oxide (TMAO) in Cardio-Metabolic Diseases: Detection, Mechanism, and Potential Therapeutics

Trimethylamine N-oxide (TMAO) is a biologically active gut microbiome-derived dietary metabolite. Recent studies have shown that high circulating plasma TMAO levels are closely associated with diseases such as atherosclerosis and hypertension, and metabolic disorders such as diabetes and hyperlipidemia, contributing to endothelial dysfunction. There is a growing interest to understand the mechanisms underlying TMAO-induced endothelial dysfunction in cardio-metabolic diseases. Endothelial dysfunction mediated by TMAO is mainly driven by inflammation and oxidative stress, which includes: (1) activation of foam cells; (2) upregulation of cytokines and adhesion molecules; (3) increased production of reactive oxygen species (ROS); (4) platelet hyperreactivity; and (5) reduced vascular tone. In this review, we summarize the potential roles of TMAO in inducing endothelial dysfunction and the mechanisms leading to the pathogenesis and progression of associated disease conditions. We also discuss the potential therapeutic strategies for the treatment of TMAO-induced endothelial dysfunction in cardio-metabolic diseases.

Formylpeptide receptor 2: Nomenclature, structure, signalling and translational perspectives: IUPHAR review 35

We discuss the fascinating pharmacology of formylpeptide receptor 2 (FPR2; often referred to as FPR2/ALX since it binds lipoxin A₄ ). Initially identified as a low-affinity 'relative' of FPR1, FPR2 presents complex and diverse biology. For instance, it is activated by several classes of agonists (from peptides to proteins and lipid mediators) and displays diverse expression patterns on myeloid cells as well as epithelial cells and endothelial cells, to name a few. Over the last decade, the pharmacology of FPR2 has progressed from being considered a weak chemotactic receptor to a master-regulator of the resolution of inflammation, the second phase of the acute inflammatory response. We propose that exploitation of the biology of FPR2 offers innovative ways to rectify chronic inflammatory states and represents a viable avenue to develop novel therapies. Recent elucidation of FPR2 structure will facilitate development of the anti-inflammatory and pro-resolving drugs of next decade.

Green Extraction of Orange Peel Waste Reduces TNFα-Induced Vascular Inflammation and Endothelial Dysfunction

Orange peel waste (OPW) is known to contain an abundant amount of polyphenols compounds such as flavonoids, well-reported for their antioxidant and anti-inflammatory properties. While OPW is generally regarded as a food waste, the opportunity to extract bioactive compounds from these “wastes” arises due to their abundance, allowing the investigation of their potential effects on endothelial cells. Hence, this study aims to use a green extraction method and pressurized hot water extraction (PHWE) to extract bioactive compounds from OPW. Liquid chromatography with UV detection (LC/UV) and liquid chromatography mass spectrometry (LC/MS) were subsequently used to identify the bioactive compounds present. Through the optimization of the extraction temperature for PHWE, our results demonstrated that extraction temperatures of 60 °C and 80 °C yield distinct bioactive compounds and resulted in better antioxidant capacity compared to other extraction temperatures or organic solvent extraction. Despite having similar antioxidant capacity, their effects on endothelial cells were distinct. Specifically, treatment of endothelial cells with 60 °C OPW extracts inhibited TNFα-induced vascular inflammation and endothelial dysfunction in vitro, suggesting that OPW possess vasoprotective effects likely mediated by anti-inflammatory effects.

Valorization of avocado seeds with antioxidant capacity using pressurized hot water extraction

The pulp of avocado (Persea Americana) is widely consumed as the primary food source, while the seed is often discarded as food waste. Increased consumption of avocado would inevitably results in production of waste by-products such as avocado seeds, hence the ability to extract phytochemicals from such waste, and upcycling to potential nutraceutical products is of great interest. The overall aim of this study is to explore avocado seeds as potential functional food through the combined use of a green extraction method, chemical standardization and pattern recognition tools, and biological characterization assays. Specifically, this study utilized an organic solvent-free extraction method, pressurized hot water extraction (PHWE) to extract phytochemicals from avocado seeds and liquid chromatography mass spectrometry (LCMS) was used to identify the phytochemicals present in the avocado seeds. Our results demonstrated that avocado seed extracts have antioxidant activity and inhibited oxidative stress-induced metabolomics changes in endothelial cells, suggesting that avocado seed extracts have vasoprotective actions.

Pyridazinones and Structurally Related Derivatives with Anti-Inflammatory Activity

Persistent inflammation contributes to a number of diseases; therefore, control of the inflammatory response is an important therapeutic goal. In an effort to identify novel anti-inflammatory compounds, we screened a library of pyridazinones and structurally related derivatives that were used previously to identify N-formyl peptide receptor (FPR) agonists. Screening of the compounds for their ability to inhibit lipopolysaccharide (LPS)-induced nuclear factor κB (NF-κB) transcriptional activity in human THP1-Blue monocytic cells identified 48 compounds with anti-inflammatory activity. Interestingly, 34 compounds were FPR agonists, whereas 14 inhibitors of LPS-induced NF-κB activity were not FPR agonists, indicating that they inhibited different signaling pathways. Further analysis of the most potent inhibitors showed that they also inhibited LPS-induced production of interleukin 6 (IL-6) by human MonoMac-6 monocytic cells, again verifying their anti-inflammatory properties. Structure–activity relationship (SAR) classification models based on atom pair descriptors and physicochemical ADME parameters were developed to achieve better insight into the relationships between chemical structures of the compounds and their biological activities, and we found that there was little correlation between FPR agonist activity and inhibition of LPS-induced NF-κB activity. Indeed, Cmpd43, a well-known pyrazolone-based FPR agonist, as well as FPR1 and FPR2 peptide agonists had no effect on the LPS-induced NF-κB activity in THP1-Blue cells. Thus, some FPR agonists reported to have anti-inflammatory activity may actually mediate their effects through FPR-independent pathways, as it is suggested by our results with this series of compounds. This could explain how treatment with some agonists known to be inflammatory (i.e., FPR1 agonists) could result in anti-inflammatory effects. Further research is clearly needed to define the molecular targets of pyridazinones and structurally related compounds with anti-inflammatory activity and to define their relationships (if any) to FPR signaling events.

Structural and conformational studies of biased agonism through formyl peptide receptors

G protein-coupled chemoattractant receptors are class A GPCRs that couple primarily to the Gi class of heterotrimeric G proteins. Initially identified for their abilities to mediate leukocyte chemotaxis, chemoattractant GPCRs such as the formyl peptide receptors (FPRs) have been known for their diverse cellular functions in response to a variety of agonists. Stimulation of FPR2, in particular, leads to ligand-dependent activation of pro-inflammatory signaling as well as anti-inflammatory and pro-resolving signaling. Recently, the structures of FPR2-Gi protein complexed with ligands of different compositions have been solved by crystallization and cryo-electron microscopy. Analysis of the structural data as well as molecular simulation have led to the findings that the FPR2 binding pocket is sufficiently large for accommodation of several different types of ligands, but in different poses. This mini-review focuses on the structural and conformational aspects of FPR2 for mechanisms underlying its biased agonism.

Therapeutic Potential of Annexin A1 Modulation in Kidney and Cardiovascular Disorders

Renal and cardiovascular disorders are very prevalent and associated with significant morbidity and mortality. Among diverse pathogenic mechanisms, the dysregulation of immune and inflammatory responses plays an essential role in such disorders. Consequently, the discovery of Annexin A1, as a glucocorticoid-inducible anti-inflammatory protein, has fueled investigation of its role in renal and cardiovascular pathologies. Indeed, with respect to the kidney, its role has been examined in diverse renal pathologies, including acute kidney injury, diabetic nephropathy, immune-mediated nephropathy, drug-induced kidney injury, kidney stone formation, and renal cancer. Regarding the cardiovascular system, major areas of investigation include the role of Annexin A1 in vascular abnormalities, atherosclerosis, and myocardial infarction. Thus, this review briefly describes major structural and functional features of Annexin A1 followed by a review of its role in pathologies of the kidney and the cardiovascular system, as well as the therapeutic potential of its modulation for such disorders.

Relationship of microRNA locus with type 2 diabetes mellitus: a case-control study

Type 2 diabetes mellitus (T2DM) is considered as a metabolic disease with hyperglycemia. Accumulating investigations have explored the important role of hereditary factors for T2DM occurrence. Some functional microRNA (miR) polymorphisms may affect their interactions with target mRNAs and result in an aberrant expression. Thus, miR variants might be considered as a biomarker of the susceptibility of T2DM. In this study, we recruited 502 T2DM cases and 782 healthy subjects. We selected miR-146a rs2910164 C>G, miR-196a2 rs11614913 T>C and miR-499 rs3746444 A>G loci and carried out an investigation to identify whether these miR loci could influence T2DM occurrence. In this investigation, a Bonferroni correction was harnessed. After adjustment, we found that rs2910164 SNP was a protective factor for T2DM (GG vs CC/CG: adjusted P = 0.010), especially in never drinking (GG vs CC/CG: adjusted P = 0.001) and BMI ≥24 kg/m2 (GG vs CC/CG: adjusted P = 0.002) subgroups. We also identified that rs11614913 SNP was a protective factor for T2DM in smoking subjects (CC/TC vs TT: adjusted P = 0.002). When we analyzed an interaction of SNP-SNP with the susceptibility tof T2DM, rs11614913/rs3746444, rs2910164/rs3746444 and rs11614913/rs2910164 combinations were not associated with the risk of T2DM. In summary, this study highlights that rs2910164 SNP decreases the susceptibility of T2DM, especially in BMI ≥24 kg/m2 and never drinking subgroups. In addition, we also identify that rs11614913 C allele decreases the susceptibility of T2DM significantly in smoking subgroup.

Pressurized Hot Water Extraction of Okra Seeds Reveals Antioxidant, Antidiabetic and Vasoprotective Activities

Abelmoschus esculentus L. Moench (okra) is a commonly consumed vegetable that consists of the seeds and peel component which are rich in polyphenolic compounds. The aim of this study is to utilize pressurized hot water extraction (PHWE) for the extraction of bioactive phytochemicals from different parts of okra. A single step PHWE was performed at various temperatures (60 °C, 80 °C, 100 °C and 120 °C) to determine which extraction temperature exhibits the optimum phytochemical profile, antioxidant and antidiabetic activities. The optimum temperature for PHWE extraction was determined at 80 °C and the biological activities of the different parts of okra (Inner Skin, Outer Skin and Seeds) were characterized using antioxidant (DPPH and ABTS), α-glucosidase and vasoprotective assays. Using PHWE, the different parts of okra displayed distinct phytochemical profiles, which consist of primarily polyphenolic compounds. The okra Seeds were shown to have the most antioxidant capacity and antidiabetic effects compared to other okra parts, likely to be attributed to their higher levels of polyphenolic compounds. Similarly, okra Seeds also reduced vascular inflammation by downregulating TNFα-stimulated VCAM-1 and SELE expression. Furthermore, metabolite profiling by LC/MS also provided evidence of the cytoprotective effect of okra Seeds in endothelial cells. Therefore, the use of PHWE may be an alternative approach for the environmentally friendly extraction and evaluation of plant extracts for functional food applications.

Annexin Animal Models-From Fundamental Principles to Translational Research

Routine manipulation of the mouse genome has become a landmark in biomedical research. Traits that are only associated with advanced developmental stages can now be investigated within a living organism, and the in vivo analysis of corresponding phenotypes and functions advances the translation into the clinical setting. The annexins, a family of closely related calcium (Ca²⁺)- and lipid-binding proteins, are found at various intra- and extracellular locations, and interact with a broad range of membrane lipids and proteins. Their impacts on cellular functions has been extensively assessed in vitro, yet annexin-deficient mouse models generally develop normally and do not display obvious phenotypes. Only in recent years, studies examining genetically modified annexin mouse models which were exposed to stress conditions mimicking human disease often revealed striking phenotypes. This review is the first comprehensive overview of annexin-related research using animal models and their exciting future use for relevant issues in biology and experimental medicine.

FPR-1 (Formyl Peptide Receptor-1) Activation Promotes Spontaneous, Premature Hypertension in Dahl Salt-Sensitive Rats

[Figure: see text].

Diabetes Attenuates the Contribution of Endogenous Nitric Oxide but Not Nitroxyl to Endothelium Dependent Relaxation of Rat Carotid Arteries

Endothelial dysfunction is a major risk factor for several of the vascular complications of diabetes, including ischemic stroke. Nitroxyl (HNO), the one electron reduced and protonated form of nitric oxide (NO•), is resistant to scavenging by superoxide, but the role of HNO in diabetes mellitus associated endothelial dysfunction in the carotid artery remains unknown. Aim: To assess how diabetes affects the role of endogenous NO• and HNO in endothelium-dependent relaxation in rat isolated carotid arteries. Methods: Male Sprague Dawley rats were fed a high-fat-diet (HFD) for 2 weeks prior to administration of low dose streptozotocin (STZ; 35 mg/kg i. p./day) for 2 days. The HFD was continued for a further 12 weeks. Sham rats were fed standard chow and administered with citrate vehicle. After 14 weeks total, rats were anesthetized and carotid arteries collected to assess responses to the endothelium-dependent vasodilator, acetylcholine (ACh) by myography. The combination of calcium-activated potassium channel blockers, TRAM-34 (1 μmol/L) and apamin (1 μmol/L) was used to assess the contribution of endothelium-dependent hyperpolarization to relaxation. The corresponding contribution of NOS-derived nitrogen oxide species to relaxation was assessed using the combination of the NO• synthase inhibitor, L-NAME (200 μmol/L) and the soluble guanylate cyclase inhibitor ODQ (10 μmol/L). Lastly, L-cysteine (3 mmol/L), a selective HNO scavenger, and hydroxocobalamin (HXC; 100 μmol/L), a NO• scavenger, were used to distinguish between NO• and HNO-mediated relaxation. Results: At study end, diabetic rats exhibited significantly retarded body weight gain and elevated blood glucose levels compared to sham rats. The sensitivity and the maximal relaxation response to ACh was significantly impaired in carotid arteries from diabetic rats, indicating endothelial dysfunction. The vasorelaxation evoked by ACh was abolished by L-NAME plus ODQ, but not affected by the apamin plus TRAM-34 combination, indicating that NOS-derived nitrogen oxide species are the predominant endothelium-derived vasodilators in sham and diabetic rat carotid arteries. The maximum relaxation to ACh was significantly decreased by L-cysteine in both sham and diabetic rats, whereas HXC attenuated ACh-induced relaxation only in sham rats, suggesting that diabetes impaired the contribution of NO•, whereas HNO-mediated vasorelaxation remained intact. Conclusion: Both NO• and HNO contribute to endothelium-dependent relaxation in carotid arteries. In diabetes, NO•-mediated relaxation is impaired, whereas HNO-mediated relaxation was preserved. The potential for preserved HNO activity under pathological conditions that are associated with oxidative stress indicates that HNO donors may represent a viable therapeutic approach to the treatment of vascular dysfunction.

Non-Alcoholic Steatohepatitis: A Review of Its Mechanism, Models and Medical Treatments

Non-alcoholic steatohepatitis (NASH) develops from non-alcoholic fatty liver disease (NAFLD). Currently, around 25% of the population is estimated to have NAFLD, and 25% of NAFLD patients are estimated to have NASH. NASH is typically characterized by liver steatosis inflammation, and fibrosis driven by metabolic disruptions such as obesity, diabetes, and dyslipidemia. NASH patients with significant fibrosis have increased risk of developing cirrhosis and liver failure. Currently, NASH is the second leading cause for liver transplant in the United States. More importantly, the risk of developing hepatocellular carcinoma from NASH has also been highlighted in recent studies. Patients may have NAFLD for years before progressing into NASH. Although the pathogenesis of NASH is not completely understood, the current “multiple-hits” hypothesis suggests that in addition to fat accumulation, elevated oxidative and ER stress may also drive liver inflammation and fibrosis. The development of clinically relevant animal models and pharmacological treatments for NASH have been hampered by the limited understanding of the disease mechanism and a lack of sensitive, non-invasive diagnostic tools. Currently, most pre-clinical animal models are divided into three main groups which includes: genetic models, diet-induced, and toxin + diet-induced animal models. Although dietary models mimic the natural course of NASH in humans, the models often only induce mild liver injury. Many genetic and toxin + diet-induced models rapidly induce the development of metabolic disruption and serious liver injury, but not without their own shortcomings. This review provides an overview of the “multiple-hits” hypothesis and an evaluation of the currently existing animal models of NASH. This review also provides an update on the available interventions for managing NASH as well as pharmacological agents that are currently undergoing clinical trials for the treatment of NASH.

Receptors for pro-resolving mediators as a therapeutic tool for smooth muscle remodeling-associated disorders

Respiratory airway, blood vessel and intestinal wall remodeling, in which smooth muscle remodeling plays a major role, is a key pathological event underlying the development of several associated diseases, including asthma, cardiovascular disorders (e.g., atherosclerosis, hypertension, and aneurism formation), and inflammatory bowel disease. However, the mechanisms underlying these remodeling processes remain poorly understood. We hypothesize that the creation of chronic inflammation-mediated networks that support and exacerbate the airway, as well as vascular and intestinal wall remodeling, is a crucial pathogenic mechanism governing the development of the associated diseases. The failed inflammation resolution might be one of the causal pathogenic mechanisms. Hence, it is reasonable to assume that applying specialized, pro-resolving mediators (SPMs), acting via cognate G-protein coupled receptors (GPCRs), could potentially be an effective pathway for treating these disorders. However, several obstacles, such as poor understanding of the SPM/receptor signaling pathways, SMP rapid inactivation as well as their complex and costly synthesis, limit their translational potential. In this connection, stable, small-molecule SPM mimetics and receptor agonists have emerged as new, potentially suitable drugs. It has been recently shown in preclinical studies that they can effectively attenuate the manifestations of asthma, atherosclerosis and Crohn's disease. Remarkably, some biased SPM receptor agonists, which cause a signaling response in the desired inflammation pro-resolving direction, revealed similar beneficial effects. These encouraging observations suggest that SPM mimetics and receptor agonists can be applied as a novel approach for the treatment of various chronic inflammation conditions, including airway, vascular and intestinal wall remodeling-associated disorders.

Antioxidant and Cytoprotective Effect of Quinoa (Chenopodium quinoa Willd.) with Pressurized Hot Water Extraction (PHWE)

Quinoa is widely noted for its nutritional value. The seed is the main edible part of the plant and exists in at least three different colors: white, red and black. This study utilized a pressurized hot water extraction (PHWE) for the extraction of phytochemicals from quinoa. Chemical fingerprints with LC/UV and LC/MS using a targeted approach and pattern recognition tools were used to evaluate the quinoa extracts. The antioxidant properties for various types of quinoa were evaluated using DPPH assay, ABTS assay and the cytoprotective effect of quinoa extracts were investigated in HMEC-1 cell line. Distinctive chemical profiles obtained from black and red quinoa were well correlated with the antioxidant activities and cytoprotective effects. The combination of PHWE, chemical standardization with LC/UV and LC/MS, pattern recognition tools and biological assay provided an approach for the evaluation and eventual production of quinoa extracts for functional food.