Angiotensin II constricts mouse iliac arteries: possible mechanism for aortic aneurysms.

Abdominal aortic aneurysms (AAA) result from maladaptive remodeling of the vascular wall and reduces structural integrity. Angiotensin II (AngII) infusion has become a standard laboratory model for studying AAA initiation and progression. We determined the different vasoactive responses of various mouse arteries to Ang II. Ex vivo isometric tension analysis was conducted on 18-week-old male C57BL/6 mice (n = 4) brachiocephalic arteries (BC), iliac arteries (IL), and abdominal (AA) and thoracic aorta (TA). Arterial rings were mounted between organ hooks, gently stretched and an AngII dose response was performed. Rings were placed in 4% paraformaldehyde for immunohistochemistry analysis to quantify peptide expression of angiotensin type 1 (AT1R) and 2 receptors (AT2R) in the endothelium, media, and adventitia. Results from this study demonstrated vasoconstriction responses in IL were significantly higher at all AngII doses when compared to BC, and TA and AA responses (maximum constriction-IL: 68.64 ± 5.47% vs. BC: 1.96 ± 1.00%; TA: 3.13 ± 0.16% and AA: 2.75 ± 1.77%, p < 0.0001). Expression of AT1R was highest in the endothelium of IL (p < 0.05) and in the media and (p < 0.05) adventitia (p < 0.05) of AA. In contrast, AT2R expression was highest in endothelium (p < 0.05), media (p < 0.01, p < 0.05) and adventitia of TA. These results suggest that mouse arteries display different vasoactive responses to AngII, and the exaggerated response in IL arteries may play a role during AAA development.

Structural Features Influencing the Bioactive Conformation of Angiotensin II and Angiotensin A: Relationship between Receptor Desensitization, Addiction, and the Blood-Brain Barrier.

The N-terminal portion of the octapeptide angiotensin II (DRVYIHPF; AngII), a vasopressor peptide that favorably binds to, and activates, AngII type 1 receptor (AT1R), has an important role in maintaining bioactive conformation. It involves all three charged groups, namely (i) the N-terminal amino group cation, (ii) the Asp sidechain anion and (iii) the Arg guanidino cation. Neutralization of any one of these three charged groups results in a substantial reduction (<5%) in bioactivity, implicating a specialized function for this cluster. In contrast, angiotensin A (ARVYIHPF; AngA) has reduced bioactivity at AT1R; however, replacement of Asp in AngII with sarcosine (N-methyl-glycine) not only restores bioactivity but increases the activity of agonist, antagonist, and inverse agonist analogues. A bend produced at the N-terminus by the introduction of the secondary amino acid sarcosine is thought to realign the functional groups that chaperone the C-terminal portion of AngII, allowing transfer of the negative charge originating at the C-terminus to be transferred to the Tyr hydroxyl-forming tyrosinate anion, which is required to activate the receptor and desensitizes the receptor (tachyphylaxis). Peptide (sarilesin) and nonpeptide (sartans) moieties, which are long-acting inverse agonists, appear to desensitize the receptor by a mechanism analogous to tachyphylaxis. Sartans/bisartans were found to bind to alpha adrenergic receptors resulting in structure-dependent desensitization or resensitization. These considerations have provided information on the mechanisms of receptor desensitization/tolerance and insights into possible avenues for treating addiction. In this regard sartans, which appear to cross the blood-brain barrier more readily than bisartans, are the preferred drug candidates.

Cisplatin treatment reduces contraction to angiotensin II by altering expression of angiotensin II receptors: a pilot study.

The renin angiotensin system is a key regulator of blood pressure homeostasis. Angiotensin type 1 (AT1R) and 2 receptors (AT2R) have been investigated as targets for cisplatin-induced acute kidney injury; however, their therapeutic potential remains inconclusive. This pilot study aimed to determined the effect that acute cisplatin treatment had on angiotensin II (AngII)-induced contraction in blood vessels and expression profiles of AT1R and AT2R in mouse arteries and kidneys. Male C57BL/6 mice at 18 week of age (n = 8) were treated with vehicle or bolus dose of cisplatin (12.5 mg/kg). Thoracic aorta (TA), adnominal aorta (AA), brachiocephalic arteries (BC), iliac arteries (IL) and kidneys were collected for isometric tension and immunohistochemistry analysis. Cisplatin treatment reduced IL contraction to AngII at all doses (p < 0.01, p < 0.001, p < 0.0001); however, AngII did not induce contraction in TA, AA or BC in either treatment group. Following cisplatin treatment, AT1R expression was significantly upregulated in the media of TA (p < 0.0001) and AA (p < 0.0001), and in the endothelium (p < 0.05) media (p < 0.0001) and adventitia (p < 0.01) of IL. Cisplatin treatment significantly reduced AT2R expression in the endothelium (p < 0.05) and media (p < 0.05) of TA. In renal tubules, both AT1R (p < 0.01) and AT2R (p < 0.05) were increased following cisplatin treatment. Herein, we report that cisplatin reduces AngII-mediated contraction in IL and may be explained by an absence of normal counterregulatory expression of AT1R and AT2R, indicating other factors are involved.

Existence of Quantum Pharmacology in Sartans: Evidence in Isolated Rabbit Iliac Arteries.

Quantum pharmacology introduces theoretical models to describe the possibility of ultra-high dilutions to produce biological effects, which may help to explain the placebo effect observed in hypertensive clinical trials. To determine this within physiology and to evaluate novel ARBs, we tested the ability of known angiotensin II receptor blockers (ARBs) (candesartan and telmisartan) used to treat hypertension and other cardiovascular diseases, as well as novel ARBs (benzimidazole-N-biphenyl tetrazole (ACC519T), benzimidazole-bis-N,N'-biphenyl tetrazole (ACC519T(2)) and 4-butyl-N,N0-bis[[20-2Htetrazol-5-yl)biphenyl-4-yl]methyl)imidazolium bromide (BV6(K+)2), and nirmatrelvir (the active ingredient in Paxlovid) to modulate vascular contraction in iliac rings from healthy male New Zealand White rabbits in responses to various vasopressors (angiotensin A, angiotensin II and phenylephrine). Additionally, the hemodynamic effect of ACC519T and telmisartan on mean arterial pressure in conscious rabbits was determined, while the ex vivo ability of BV6(K+)2 to activate angiotensin-converting enzyme-2 (ACE2) was also investigated. We show that commercially available and novel ARBs can modulate contraction responses at ultra-high dilutions to different vasopressors. ACC519T produced a dose-dependent reduction in rabbit mean arterial pressure while BV6(K+)2 significantly increased ACE2 metabolism. The ability of ARBs to inhibit contraction responses even at ultra-low concentrations provides evidence of the existence of quantum pharmacology. Furthermore, the ability of ACC519T and BV6(K+)2 to modulate blood pressure and ACE2 activity, respectively, indicates their therapeutic potential against hypertension.

Undercarboxylated osteocalcin has no adverse effect on endothelial function in rabbit aorta or human vascular cells.

Undercarboxylated osteocalcin (ucOC) improves glucose metabolism; however, its effects on endothelial cell function are unclear. We examined the biological effect of ucOC on endothelial function in animal models ex vivo and human cells in vitro. Isometric tension and immunohistochemistry techniques were used on the aorta of male New Zealand white rabbits and cell culture techniques were used on human aortic endothelial cells (HAECs) to assess the effect of ucOC in normal and high-glucose environments. Overall, ucOC, both 10 and 30 ng/ml, did not significantly alter acetylcholine-induced blood vessel relaxation in rabbits (p > .05). UcOC treatment did not cause any significant changes in the immunoreactivity of cellular signalling markers (p > .05). In HAEC, ucOC did not change any of the assessed outcomes (p > .05). UcOC has no negative effects on endothelial function which is important to reduce the risks of off target adverse effects if it will be used as a therapeutic option for metabolic disease in the future.

Can SARS-CoV-2 Virus Use Multiple Receptors to Enter Host Cells?

The occurrence of the novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), responsible for coronavirus disease 2019 (COVD-19), represents a catastrophic threat to global health. Protruding from the viral surface is a densely glycosylated spike (S) protein, which engages angiotensin-converting enzyme 2 (ACE2) to mediate host cell entry. However, studies have reported viral susceptibility in intra- and extrapulmonary immune and non-immune cells lacking ACE2, suggesting that the S protein may exploit additional receptors for infection. Studies have demonstrated interactions between S protein and innate immune system, including C-lectin type receptors (CLR), toll-like receptors (TLR) and neuropilin-1 (NRP1), and the non-immune receptor glucose regulated protein 78 (GRP78). Recognition of carbohydrate moieties clustered on the surface of the S protein may drive receptor-dependent internalization, accentuate severe immunopathological inflammation, and allow for systemic spread of infection, independent of ACE2. Furthermore, targeting TLRs, CLRs, and other receptors (Ezrin and dipeptidyl peptidase-4) that do not directly engage SARS-CoV-2 S protein, but may contribute to augmented anti-viral immunity and viral clearance, may represent therapeutic targets against COVID-19.

From Angiotensin II to Cyclic Peptides and Angiotensin Receptor Blockers (ARBs): Perspectives of ARBs in COVID-19 Therapy.

The octapeptide hormone angiotensin II is one of the most studied peptides with the aim of designing and synthesizing non-peptide mimetics for oral administration. To achieve this, cyclizations at different positions within the peptide molecule has been a useful strategy to define the active conformation. These studies on angiotensin II led to the discovery of Sarmesin, a type II angiotensin II antagonist, and the breakthrough non-peptide mimetic Losartan, the first in a series of sartans marketed as a new generation of anti-hypertensive drugs in the 1990s. Angiotensin II receptor blockers (ARBS) and angiotensin I converting enzyme inhibitors (ACEI) were recently reported to protect hypertensive patients infected with SARS-CoV-2. The renin-angiotensin system (RAS) inhibitors reduce excess angiotensin II and increase antagonist heptapeptides alamandine and aspamandine which counterbalance angiotensin II and maintain homeostasis and vasodilation.

Imipridone enhances vascular relaxation via FOXO1 pathway.

Cardiovascular complications are a side effect of cancer therapy, potentially through reduced blood vessel function. ONC201 (TIC10) is currently used in phase 2 clinical trials to treat high-grade gliomas. TIC10 is a phosphatidylinositol 3-kinase (PI3K)/AKT/extracellular signal-regulated kinase (ERK) inhibitor that induces apoptosis via upregulation of TNF-related apoptosis-inducing ligand, which via stimulation of FOXO and death receptor could increase eNOS upregulation. This has the potential to improve vascular function through increased NO bioavailability. Our aim was to investigate the role of TIC10 on vascular function to determine if it would affect the risk of CVD. Excised abdominal aorta from White New Zealand male rabbits were cut into rings. Vessels were incubated with TIC10 and AS1842856 (FOXO1 inhibitor) followed by cumulative doses of acetylcholine (Ach) to assess vessel function. Vessels were then processed for immunohistochemistry. Incubation of blood vessels with TIC10 resulted in enhanced vasodilatory capacity. Combination treatment with the FOXO1 inhibitor and TIC10 resulted in reduced vascular function compared to control. Immunohistochemical analysis indicated a 3-fold increase in death receptor 5 (DR5) expression in the TIC10-treated blood vessels but the addition of the FOXO1 inhibitor downregulated DR5 expression. The expression of DR4 receptor was not significantly increased in the presence of TIC10; however, addition of the FOXO1 inhibitor downregulated expression. TIC10 has the capacity to improve the function of healthy vessels when stimulated with the vasodilator Ach. This highlights its therapeutic potential not only in cancer treatment without cardiovascular side effects, but also as a possible drug to treat established CVD.

The potential actions of angiotensin-converting enzyme II (ACE2) activator diminazene aceturate (DIZE) in various diseases.

The renin angiotensin system (RAS) regulates fluid balance, blood pressure and maintains vascular tone. The potent vasoconstrictor angiotensin II (Ang II) produced by angiotensin-converting enzyme (ACE) comprises the classical RAS. The non-classical RAS involves the conversion of Ang II via ACE2 into the vasodilator Ang (1-7) to counterbalance the effects of Ang II. Furthermore, ACE2 converts AngA into another vasodilator named alamandine. The over activation of the classical RAS (increased vasoconstriction) and depletion of the non-classical RAS (decreased vasodilation) results in vascular dysfunction. Vascular dysfunction is the leading cause of atherosclerosis and cardiovascular disease (CVD). Additionally, local RAS is expressed in various tissues and regulates cellular functions. RAS dysregulation is involved in other several diseases such as inflammation, renal dysfunction and even cancer growth. An approach in restoring vascular dysfunction and other pathological diseases is to either increase the activity of ACE2 or reduce the effect of the classical RAS by counterbalancing Ang II effects. The antitrypanosomal agent, diminazene aceturate (DIZE), is one approach in activating ACE2. DIZE has been shown to exert beneficial effects in CVD experimental models of hypertension, myocardial infarction, type 1 diabetes and atherosclerosis. Thus, this review focuses on DIZE and its effect in several tissues such as blood vessels, cardiac, renal, immune and cancer cells.

The therapeutic effect of B-type natriuretic peptides in acute decompensated heart failure.

B-type natriuretic peptide (BNP) exhibits roles in natriuresis and diuresis, making it an ideal drug that may aid in diuresing a fluid-overloaded patient with poor or worsening renal function. Several randomized clinical trials have tested the hypothesis that infusions of pharmacological doses of BNP to acute heart failure (HF) patients may enhance decongestion and preserve renal function in this clinical setting. Unfortunately, none of these have demonstrated beneficial outcomes. The current challenge for BNP research in acute HF lies in addressing a failure of concept and a reluctance to abandon an ineffective research model. Future success will necessitate a detailed understanding of the mechanism of action of BNP, as well as better integration of basic and clinical science.

The Effect of Recombinant Undercarboxylated Osteocalcin on Endothelial Dysfunction.

Low circulating levels of undercarboxylated osteocalcin (ucOC) is associated with a higher risk of cardiovascular disease, yet whether ucOC has a direct effect on endothelium-dependent vasorelaxation, or in proximity to its postulated receptor, the class CG protein-coupled receptor (GPCR6A), in blood vessels remains unclear. Immunohistochemistry and proximity ligation assays were used to localize the presence of ucOC and GPRC6A and to determine the physical proximity (< 40 nm) in radial artery segments collected from patients undergoing coronary artery bypass surgery (n = 6) which exhibited calcification (determined by Von Kossa) and aorta from New Zealand white rabbits exhibiting atherosclerotic plaques. Endothelium-dependent vasorelaxation was assessed using cumulative doses of acetylcholine in vitro on abdominal aorta of rabbits fed a normal chow diet (n = 10) and a 4-week atherogenic diet (n = 9) pre-incubated with ucOC (10 ng/mL) or vehicle. Both ucOC and GPRC6A were localized in human and rabbit diseased-blood vessels. Proximity ligation assay staining demonstrated physical proximity of ucOC with GPRC6A only within plaques in rabbit arteries and the endothelium layer of rabbit arterioles. Endothelium-dependent vasorelaxation was impaired in atherogenic abdominal aorta compared to healthy aorta and ucOC attenuated this impairment. ucOC attenuated impaired endothelium-dependent vasorelaxation in rabbit abdominal aorta following an atherogenic diet, however, this effect may be independent of GPRC6A. It is important that future studies determine the underlying cellular mechanisms by which ucOC effects blood vessels as well as whether it can be used as a therapeutic agent against the progression of atherosclerosis.

Methylation of the first exon in the erythropoietin receptor gene does not correlate with its mRNA and protein level in cancer cells.

BACKGROUND: Erythropoietin receptor (EPOR) is a functional membrane-bound cytokine receptor. Erythropoietin (EPO) represents an important hematopoietic factor for production, maturation and differentiation of erythroid progenitors. In non-hematopoietic tissue, EPO/EPOR signalization could also play cytoprotective and anti-apoptotic role. Several studies identified pro-stimulating EPO/EPOR effects in tumor cells; however, numerous studies opposed this fact due to the usage of unspecific EPOR antibodies and thus potential absence or very low levels of EPOR in tumor cells. It seems that this problem is more complex and therefore we have decided to focus on EPOR expression at several levels such as the role of methylation in the regulation of EPOR expression, identification of possible EPOR transcripts and the presence of EPOR protein in selected tumor cells. METHODS: Methylation status was analysed by bisulfite conversion reaction, PCR and sequencing. The expression of EPOR was monitored by quantitative RT-PCR and western blot analysis. RESULTS: In this study we investigated the methylation status of exon 1 of EPOR gene in selected human cancer cell lines. Our results indicated that CpGs methylation in exon 1 do not play a significant role in the regulation of EPOR transcription. However, methylation status of EPOR exon 1 was cell type dependent. We also observed the existence of two EPOR splice variants in human ovarian adenocarcinoma cell line - A2780 and confirmed the expression of EPOR protein in these cells using specific A82 anti-EPOR antibody. CONCLUSION: We outlined the methylation status of all selected cancer cell lines in exon 1 of EPOR gene and these results could benefit future investigations. Moreover, A82 antibody confirmed our previous results demonstrating the presence of functional EPOR in human ovarian adenocarcinoma A2780 cells.

The effect of Betanin parenteral pretreatment on Jejunal and pulmonary tissue histological architecture and inflammatory response after Jejunal ischemia-reperfusion injury.

Intestinal ischemic-reperfusion (IR) injury has detrimental effects on both local and distant organs in the body. Betanin is known for its antioxidant properties, and it is found mostly in vegetables. Therefore, the aim of the present study was to test the hypothesis that betanin administration prior intestinal IR, may be beneficial in protecting jejunal mucosa and lung parenchyma against IR damage. Male specific pathogen-free Charles River Wistar rats were used (n = 42). Betanin (50 mg/kg) was administered intraperitoneally 30 min before ischemia of the superior mesenteric artery lasting 1 h, followed by 1, 4 and 24 h of reperfusion. Immunohistochemical as well as histomorphometrical analysis indicated a protective effect of betanin pretreatment on jejunal tissue. Regarding morphometrical analysis betanin significantly (p < 0.01) augments intestinal villus height after 24 of reperfusion comparing to early stages. Betanin application reduced number of mast cells population in early reperfusion periods (p < 0.05). The protective effect of betanin on lung parenchyma, was detected in late reperfusion period (24 h) with improvement of histopathological injury index and morphometric analysis (p < 0.001 for both). The improvement of histopathological injury index (p < 0.001) and morphometric analysis (p < 0.001) during the late reperfusion period, suggests a protective effect of betanin on lung parenchyma. Moreover, suppression of the inflammatory response was mirrored by the reduction of myeloperoxidase (MPO) positive cells within lung parenchyma after 1 and 4 h of reperfusion (p < 0.001). Especially, during the first 4 h of reperfusion after betanin administration, a reduction of 74% of the polymorphonuclear neutrophils infiltration (MPO positive cell population) and of a nearly 46% of active MCs was observed. Upon morphometric examination, the lung histological architecture after 24 h of reperfusion appeared to be almost 100% better following betanin treatment, with 25% thinner interalveolar septa and 20% larger alveolar surface for respiratory gas exchange. The results suggest that betanin pretreatment protects the jejunal mucosa and the lung parenchyma, as well as reduces the inflammatory cell density after intestinal IR injury.

Putative Nox2 inhibitors worsen homocysteine-induced impaired acetylcholine-mediated relaxation.

BACKGROUND AND AIM: Increased homocysteine (Hcy) is associated with coronary artery disease (CAD). Hcy increases reactive oxygen species (ROS) via NADPH oxidases (Nox), reducing acetylcholine-mediated vasorelaxation. We aimed to determine if putative Nox2 inhibitors prevent Hcy-impaired acetylcholine-mediated vasorelaxation. METHODS AND RESULTS: New Zealand White rabbit and wild-type (C57BL/6) and Nox2-/- (NOX) mice aortic rings were mounted in organ baths. Rabbit rings were incubated with either apocynin (10 µM), gp91ds-tat (GP, 1 µM) or PhoxI2 (1 µM) and mice rings GP (1 µM) only. Some rabbit rings were incubated with 3 mM Hcy, before pre-contraction, followed by dose-response relaxation to acetylcholine (ACh; 0.01µM-10µM). In rabbit rings treated with Hcy and GP, O2‾ donor pyrogallol (1 µM) or Akt activator SC79 (1 µM) was added 5 min before ACh. Mice rings were used to compare Nox2 deletion to normal acetylcholine-mediated relaxation. In rabbits, Hcy reduced acetylcholine-mediated relaxation vs. control (p < 0.0001). Treatment + Hcy reduced relaxation compared with treatment alone (p < 0.0001). Pyrogallol and SC79 reversed the response of GP + Hcy (p = 0.0001). In mice, Nox2 deletion reduced acetylcholine-mediated vasorelaxation. Rabbit tissue analysis revealed that Hcy reduced eNOS phosphorylation at Thr495 and increased eNOS phosphorylation at Ser1177; no further alteration at Thr495 was observed with GP. In contrast, GP prevented increased phosphorylation at Ser1177. CONCLUSIONS: Apocynin, GP and PhoxI2 worsens acetylcholine-mediated vascular relaxation in rabbit aorta, which is supported by results from mouse Nox2 deletion data. These inhibitors worsen Hcy-induced vascular dysfunction, suggesting that current putative Nox2 inhibitors might not be useful in treating HHcy.

Anticancer Activities of Thymus vulgaris L. in Experimental Breast Carcinoma in Vivo and in Vitro.

Naturally-occurring mixtures of phytochemicals present in plant foods are proposed to possess tumor-suppressive activities. In this work, we aimed to evaluate the antitumor effects of Thymus vulgaris L. in in vivo and in vitro mammary carcinoma models. Dried T. vulgaris (as haulm) was continuously administered at two concentrations of 0.1% and 1% in the diet in a chemically-induced rat mammary carcinomas model and a syngeneic 4T1 mouse model. After autopsy, histopathological and molecular analyses of rodent mammary carcinomas were performed. In addition, in vitro evaluations using MCF-7 and MDA-MB-231 cells were carried out. In mice, T. vulgaris at both doses reduced the volume of 4T1 tumors by 85% (0.1%) and 84% (1%) compared to the control, respectively. Moreover, treated tumors showed a substantial decrease in necrosis/tumor area ratio and mitotic activity index. In the rat model, T. vulgaris (1%) decreased the tumor frequency by 53% compared to the control. Analysis of the mechanisms of anticancer action included well-described and validated diagnostic and prognostic markers that are used in both clinical approach and preclinical research. In this regard, the analyses of treated rat carcinoma cells showed a CD44 and ALDH1A1 expression decrease and Bax expression increase. Malondialdehyde (MDA) levels and VEGFR-2 expression were decreased in rat carcinomas in both the T. vulgaris treated groups. Regarding the evaluations of epigenetic changes in rat tumors, we found a decrease in the lysine methylation status of H3K4me3 in both treated groups (H3K9m3, H4K20m3, and H4K16ac were not changed); up-regulations of miR22, miR34a, and miR210 expressions (only at higher doses); and significant reductions in the methylation status of four gene promoters-ATM serin/threonine kinase, also known as the NPAT gene (ATM); Ras-association domain family 1, isoform A (RASSF1); phosphatase and tensin homolog (PTEN); and tissue inhibitor of metalloproteinase-3 (TIMP3) (the paired-like homeodomain transcription factor (PITX2) promoter was not changed). In vitro study revealed the antiproliferative and proapoptotic effects of essential oils of T. vulgaris in MCF-7 and MDA-MB-231 cells (analyses of 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS); 5-bromo-20-deoxyuridine (BrdU); cell cycle; annexin V/PI; caspase-3/7; Bcl-2; PARP; and mitochondrial membrane potential). T. vulgaris L. demonstrated significant chemopreventive and therapeutic activities against experimental breast carcinoma.

Dietary Phytochemicals Targeting Cancer Stem Cells.

There is an increasing awareness of the importance of a diet rich in fruits and vegetables for human health. Cancer stem cells (CSCs) are characterized as a subpopulation of cancer cells with aberrant regulation of self-renewal, proliferation or apoptosis leading to cancer progression, invasiveness, metastasis formation, and therapy resistance. Anticancer effects of phytochemicals are also directed to target CSCs. Here we provide a comprehensive review of dietary phytochemicals targeting CSCs. Moreover, we evaluate and summarize studies dealing with effects of dietary phytochemicals on CSCs of various malignancies in preclinical and clinical research. Dietary phytochemicals have a significant impact on CSCs which may be applied in cancer prevention and treatment. However, anticancer effects of plant derived compounds have not yet been fully investigated in clinical research.

Melatonin May Increase Anticancer Potential of Pleiotropic Drugs.

Melatonin (N-acetyl-5-methoxytryptamine) is not only a pineal hormone, but also an ubiquitary molecule present in plants and part of our diet. Numerous preclinical and some clinical reports pointed to its multiple beneficial effects including oncostatic properties, and as such, it has become one of the most aspiring goals in cancer prevention/therapy. A link between cancer and inflammation and/or metabolic disorders has been well established and the therapy of these conditions with so-called pleiotropic drugs, which include non-steroidal anti-inflammatory drugs, statins and peroral antidiabetics, modulates a cancer risk too. Adjuvant therapy with melatonin may improve the oncostatic potential of these drugs. Results from preclinical studies are limited though support this hypothesis, which, however, remains to be verified by further research.

Nitric oxide is required for the insulin sensitizing effects of contraction in mouse skeletal muscle.

KEY POINTS: People with insulin resistance or type 2 diabetes can substantially increase their skeletal muscle glucose uptake during exercise and insulin sensitivity after exercise. Skeletal muscle nitric oxide (NO) is important for glucose uptake during exercise, although how prior exercise increases insulin sensitivity is unclear. In the present study, we examined whether NO is necessary for normal increases in skeletal muscle insulin sensitivity after contraction ex vivo in mouse muscle. The present study uncovers, for the first time, a novel role for NO in the insulin sensitizing effects of ex vivo contraction, which is independent of blood flow. ABSTRACT: The factors regulating the increase in skeletal muscle insulin sensitivity after exercise are unclear. We examined whether nitric oxide (NO) is required for the increase in insulin sensitivity after ex vivo contractions. Isolated C57BL/6J mouse EDL muscles were contracted for 10 min or remained at rest (basal) with or without the NO synthase (NOS) inhibition (NG -monomethyl-l-arginine; l-NMMA; 100 µm). Then, 3.5 h post contraction/basal, muscles were exposed to saline or insulin (120 µU ml-1 ) with or without l-NMMA during the last 30 min. l-NMMA had no effect on basal skeletal muscle glucose uptake. The increase in muscle glucose uptake with insulin (57%) was significantly (P < 0.05) greater after prior contraction (140% increase). NOS inhibition during the contractions had no effect on this insulin-sensitizing effect of contraction, whereas NOS inhibition during insulin prevented the increase in skeletal muscle insulin sensitivity post-contraction. Soluble guanylate cyclase inhibition, protein kinase G (PKG) inhibition or cyclic nucleotide phosphodiesterase inhibition each had no effect on the insulin-sensitizing effect of prior contraction. In conclusion, NO is required for increases in insulin sensitivity several hours after contraction of mouse skeletal muscle via a cGMP/PKG independent pathway.

Oregano demonstrates distinct tumour-suppressive effects in the breast carcinoma model.

PURPOSE: There has been a considerable interest in the identification of natural plant foods for developing effective agents against cancer. Thus, the anti-tumour effects of oregano in the in vivo and in vitro breast cancer model were evaluated. METHODS: Lyophilized oregano (ORE) was administered at two concentrations of 0.3 and 3 % through diet. The experiment was terminated 14 weeks after carcinogen administration. At autopsy, mammary tumours were removed and prepared for histopathological and immunohistochemical analysis. Moreover, in vitro evaluation in MCF-7 cells was carried out. RESULTS: Low-dose ORE suppressed tumour frequency by 55.5 %, tumour incidence by 44 %, and tumour volume by 44.5 % compared to control animals. Analysis of rat tumour cells showed Ki67, VEGFR-2, CD24, and EpCAM expression decrease and caspase-3 expression increase after low-dose ORE treatment. High-dose ORE lengthened tumour latency by 12.5 days; moreover, Bcl-2, VEGFR-2, CD24, and EpCAM expression decrease and caspase-3 expression increase in carcinoma cells were observed. Histopathological analysis revealed a decrease in the ratio of high-/low-grade carcinomas in both treated groups. In vitro studies showed that ORE decreased survival and proliferation of MCF-7 cells. In ORE-treated MCF-7 cells, an increase in cells expressing sub-G 0/G 1 DNA content and an increase in the percentage of annexin V/PI positive MCF-7 cells were observed. In vitro, both caspase-dependent and possible non-caspase-dependent apoptotic pathways were found. The deactivation of anti-apoptotic activity of Bcl-2, a decrease in mitochondrial membrane potential, and the activation of mitochondrial apoptosis pathway were observed in the ORE-treated MCF-7 cells. CONCLUSIONS: Our results demonstrate, for the first time, a distinct tumour-suppressive effect of oregano in the breast cancer model.

Chili pepper as a body weight-loss food.

Chili has culinary as well as medical importance. Studies in humans, using a wide range of doses of chili intake (varying from a single meal to a continuous uptake for up to 12 weeks), concluded that it facilitates weight loss. In regard to this, the main targets of chili are fat metabolism, energy expenditure, and thermogenesis. To induce weight loss, the active substance of chili, capsaicin, activates Transient Receptor Potential Cation Channel sub-family V member 1 (TRPV1) channels) receptors causing an increase in intracellular calcium levels and triggering the sympathetic nervous system. Apart from TRPV1, chili directly reduces energy expenditure by activating Brown Adipose Tissue. Weight loss by chili is also the result of an improved control of insulin, which supports weight management and has positive effects for treatment for diseases like obesity, diabetes and cardiovascular disorders. This review summarizes the major pathways by which chili contributes to ameliorating parameters that help weight management and how the consumption of chili can help in accelerating weight loss through dietary modifications.