Disruption of Angiogenesis by Anthocyanin-Rich Extracts of Hibiscus sabdariffa

The Ameliorative Role of Hibiscetin against High-Fat Diets and Streptozotocin-Induced Diabetes in Rodents via Inhibiting Tumor Necrosis Factor-α, Interleukin-1β, and Malondialdehyde Level

Hibiscetin, as one of the main bioactive constituents of Hibiscus sabdariffa, has many pharmacological activities, but its antihyperglycemic activity has not been fully interpreted yet. The current research was developed from this perspective. The study intended to appraise the antidiabetic capability of hibiscetin in a high-fat diet (HFD) and streptozotocin (STZ; 50 mg/kg, intraperitoneally)-induced diabetes in an experimental animal. The efficiency of hibiscetin at 10 mg/kg in an “HFD/STZ model” remedy in rats with experimentally caused diabetes was explored for 42 days. The efficacy of hibiscetin was observed on several diabetes parameters. The average body weight and an array of biochemical markers were determined, including blood glucose, insulin, total protein (TP), lipid profile, aspartate aminotransferase (AST), alanine aminotransferase (ALT), IL-6, IL-1β, tumor necrosis factor-α (TNF-α), adiponectin, leptin, resistin, malondialdehyde (MDA), catalase (CAT), glutathione (GSH), and superoxide dismutase (SOD). The antidiabetic benefits of hibiscetin were proven by a substantial reduction in blood glucose, lipid profile (TC and TG), total protein, IL-6, IL-1β, MDA, TNF-α, leptin, adiponectin, ALT, and AST in the therapy group compared to the diabetic disease standard. Furthermore, hibiscetin therapy also reversed the lowered levels of insulin, resistin, GSH, SOD, and CAT in diabetic rats. It was determined that hibiscetin may be beneficial in terms of reducing diabetes problems due to its effects on both oxidative stress and inflammation and that more research for this design should be conducted.

Angioprevention of Urologic Cancers by Plant-Derived Foods

The number of cancer cases worldwide keeps growing unstoppably, despite the undeniable advances achieved by basic research and clinical practice. Urologic tumors, including some as prevalent as prostate, bladder or kidney tumors, are no exceptions to this rule. Moreover, the fact that many of these tumors are detected in early stages lengthens the duration of their treatment, with a significant increase in health care costs. In this scenario, prevention offers the most cost-effective long-term strategy for the global control of these diseases. Although specialized diets are not the only way to decrease the chances to develop cancer, epidemiological evidence support the role of certain plant-derived foods in the prevention of urologic cancer. In many cases, these plants are rich in antiangiogenic phytochemicals, which could be responsible for their protective or angiopreventive properties. Angiogenesis inhibition may contribute to slow down the progression of the tumor at very different stages and, for this reason, angiopreventive strategies could be implemented at different levels of chemoprevention, depending on the targeted population. In this review, epidemiological evidence supporting the role of certain plant-derived foods in urologic cancer prevention are presented, with particular emphasis on their content in bioactive phytochemicals that could be used in the angioprevention of cancer.

Fatty Acid Composition and Stoichiometry Determine the Angiogenesis Microenvironment

The current study tested the hypothesis of whether specific lipids may control angiogenic reactions. Using the chorioallantoic membrane assay of the chick embryo, new vessel formation was analyzed quantitatively by gas chromatography and mass spectrometry as well as bioinformatics tools including an angiogenesis analyzer. Our biochemical experiments showed that a specific lipid composition and stoichiometry determine the angiogenesis microenvironment to accelerate or inhibit vessel formation. Specific lipids of angiogenesis determinants in the vessel area and the non-vessel area were identified as nitrooleic acid, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), palmitic acid, oleic acid, linoleic acid, linolenic acid, epoxyoleic acid, lysophosphatidylcholine (LPC), cholesterol, 7-ketocholesterol, and docosahexaenoyl lysophosphatidylcholine (DHA-LPC). Vessel formation happens on the surface area of the hydrophilic membrane of the yolk. Our biochemical data demonstrated that angiogenesis was followed in the white lipid complex area to generate more branches, junctions, segments, and extremities. We analyzed lipid fragments in the vessel, non-vessel, and albumen area to show that each area contains a specific lipid composition and stoichiometry. Mass spectrometry data demonstrated that the vessel area has higher concentrations of nitrooleic acid, palmitic acid, stearic acid, LPC, lysophosphatidylethanolamine, cholesterol, oleic acid, linoleic acid, 7-ketocholesterol, and DHA-LPC; however, DHA and EPA were abundant in the hydrophobic non-vessel area. The purpose of vessel formation is to wrap up the yolk area to transport nutrients including specific fatty acids. Besides, angiogenesis requires aqueous albumen shown by distance-dependent vessel formation from albumen and oxygen. Higher concentrations of fatty acids are required for energy and carbon structure from the carbon-carbon bond, membrane building blocks, and amphiphilic detergent to solubilize a hydrophobic environment in the aqueous blood layer. The current study may guide that the uncovered hydrophobic or zwitterionic molecules such as DHA and DHA-LPC may control angiogenesis as antiangiogenic or proangiogenic molecules as potential drug targets for treating uncontrolled angiogenesis-related diseases, including diabetic retinopathy and age-related macular degeneration.

Mechanistic dissection of diabetic retinopathy using the protein-metabolite interactome

Purpose

The current study aims to determine the molecular mechanisms of diabetic retinopathy (DR) using the protein-protein interactome and metabolome map. We examined the protein network of novel biomarkers of DR for direct (physical) and indirect (functional) interactions using clinical target proteins in different models.

Methods

We used proteomic tools including 2-dimensional gel electrophoresis, mass spectrometry analysis, and database search for biomarker identification using in vivo murine and human model of diabetic retinopathy and in vitro model of oxidative stress. For the protein interactome and metabolome mapping, various bioinformatic tools that include STRING and OmicsNet were used.

Results

We uncovered new diabetic biomarkers including prohibitin (PHB), dynamin 1, microtubule-actin crosslinking factor 1, Toll-like receptor (TLR 7), complement activation, as well as hypothetical proteins that include a disintegrin and metalloproteinase (ADAM18), vimentin III, and calcium-binding C2 domain-containing phospholipid-binding switch (CAC2PBS) using a proteomic approach. Proteome networks of protein interactions with diabetic biomarkers were established using known DR-related proteome data. DR metabolites were interconnected to establish the metabolome map. Our results showed that mitochondrial protein interactions were changed during hyperglycemic conditions in the streptozotocin-treated murine model and diabetic human tissue.

Conclusions

Our interactome mapping suggests that mitochondrial dysfunction could be tightly linked to various phases of DR pathogenesis including altered visual cycle, cytoskeletal remodeling, altered lipid concentration, inflammation, PHB depletion, tubulin phosphorylation, and altered energy metabolism. The protein-metabolite interactions in the current network demonstrate the etiology of retinal degeneration and suggest the potential therapeutic approach to treat DR.

Noninvasive temporal detection of early retinal vascular changes during diabetes

Diabetes associated complications, including diabetic retinopathy and loss of vision, are major health concerns. Detecting early retinal vascular changes during diabetes is not well documented, and only few studies have addressed this domain. The purpose of this study was to noninvasively evaluate temporal changes in retinal vasculature at very early stages of diabetes using fundus images from preclinical models of diabetes. Non-diabetic and Akita/+ male mice with different duration of diabetes were subjected to fundus imaging using a Micron III imaging system. The images were obtained from 4 weeks- (onset of diabetes), 8 weeks-, 16 weeks-, and 24 weeks-old male Akita/+ and non-diabetic mice. In total 104 fundus images were subjected to analysis for various feature extractions. A combination of Canny Edge Detector and Angiogenesis Analyzer plug-ins in ImageJ were utilized to quantify various retinal vascular changes in fundus images. Statistical analyses were conducted to determine significant differences in the various extracted features from fundus images of diabetic and non-diabetic animals. Our novel image analysis method led to extraction of over 20 features. These results indicated that some of these features were significantly changed with a short duration of diabetes, and others remained the same but changed after longer duration of diabetes. These patterns likely distinguish acute (protective) and chronic (damaging) associated changes with diabetes. We show that with a combination of various plugging one can extract over 20 features from retinal vasculature fundus images. These features change during diabetes, thus allowing the quantification of quality of retinal vascular architecture as biomarkers for disease progression. In addition, our method was able to identify unique differences among diabetic mice with different duration of diabetes. The ability to noninvasively detect temporal retinal vascular changes during diabetes could lead to identification of specific markers important in the development and progression of diabetes mediated-microvascular changes, evaluation of therapeutic interventions, and eventual reversal of these changes in order to stop or delay disease progression.

Dual Switch Mechanism of Erythropoietin as an Antiapoptotic and Pro-Angiogenic Determinant in the Retina

Constant or intense light degenerates the retina and retinal pigment epithelial cells. Light generates reactive oxygen species and nitric oxide leading to initial reactions of retinal degeneration. Apoptosis is the primary mechanism of abnormal death of photoreceptors, retinal ganglion cells, or retinal pigment epithelium (RPE) in degenerative retinal diseases, including diabetic retinopathy and age-related macular degeneration. The current study evaluated the function of erythropoietin (EPO) on angiogenesis and apoptosis in the retina and RPE under oxidative stress. We determined the pro-angiogenic and antiapoptotic mechanism of EPO under stress conditions using a conditional EPO knockdown model using siRNA, EPO addition, proteomics, immunocytochemistry, and bioinformatic analysis. Our studies verified that EPO protected retinal cells from light-, hypoxia-, hyperoxia-, and hydrogen peroxide-induced apoptosis through caspase inhibition, whereas up-regulated angiogenic reactions through vascular endothelial growth factor (VEGF) and angiotensin pathway. We demonstrated that the EPO expression in the retina and subsequent serine/threonine/tyrosine kinase phosphorylations might be linked to oxidative stress response tightly to determining angiogenesis and apoptosis. Neuroprotective roles of EPO may involve the balance between antiapoptotic and pro-angiogenic signaling molecules, including BCL-xL, c-FOS, caspase-3, nitric oxide, angiotensin, and VEGF receptor. Our data indicate a new therapeutic application of EPO toward retinal degeneration based on the dual roles in apoptosis and angiogenesis at the molecular level under oxidative stress.

Oleic Acid, Cholesterol, and Linoleic Acid as Angiogenesis Initiators

The current study determined the natural angiogenic molecules using an unbiased metabolomics approach. A chick chorioallantoic membrane (CAM) model was used to examine pro- and antiangiogenic molecules, followed by gas chromatography-mass spectrometry (GCMS) analysis. Vessel formation was analyzed quantitatively using the angiogenic index (p < 0.05). At embryonic day one, a white streak or circle area was observed when vessel formation begins. GCMS analysis and database search demonstrated that angiogenesis may initiate when oleic, cholesterol, and linoleic acids increased in the area of angiogenic reactions. The gain of function study was conducted by the injection of cholesterol and oleic acid into a chick embryo to determine the role of each lipid in angiogenesis. We propose that oleic acid, cholesterol, and linoleic acid are natural molecules that set the platform for the initiation stage of angiogenesis before other proteins including the vascular endothelial growth factor, angiopoietin, angiotensin, and erythropoietin join as the angiome in sprout extension and vessel maturation.