Support for a photoprotective function of winter leaf reddening in nitrogen-deficient individuals of Lonicera japonica

Plants growing in high-light environments during winter often exhibit leaf reddening due to synthesis of anthocyanin pigments, which are thought to alleviate photooxidative stress associated with low-temperature photoinhibition through light attenuation and/or antioxidant activity. Seasonal high-light stress can be further exacerbated by a limited photosynthetic capacity, such as nitrogen-deficiency. In the present study, we test the following hypotheses using three populations of the semi-evergreen vine Lonicera japonica: (1) nitrogen deficiency corresponds with reduced photosynthetic capacity; (2) individuals with reduced photosynthetic capacity synthesize anthocyanin pigments in leaves during winter; and (3) anthocyanin pigments help alleviate high-light stress by attenuating green light. All populations featured co-occurring winter-green and winter-red leafed individuals on fully-exposed (high-light), south-facing slopes in the Piedmont of North Carolina, USA. Consistent with our hypotheses, red leaves consistently exhibited significantly lower foliar nitrogen than green leaves, as well as lower total chlorophyll, quantum yield efficiency, carboxylation efficiency, and photosynthesis at saturating irradiance (Asat). Light-response curves measured using ambient sunlight versus red-blue LED (i.e., lacking green wavelengths) demonstrated significantly reduced quantum yield efficiency and a higher light compensation point under sunlight relative to red-blue LED in red leaves, but not in green leaves, consistent with a (green) light-attenuating function of anthocyanin pigments. These results are consistent with the hypothesis that intraspecific anthocyanin synthesis corresponds with nitrogen deficiency and reduced photosynthetic capacity within populations, and support a light-attenuating function of anthocyanin pigments.

Protective effect of nuclear factor E2-related factor 2 on inflammatory cytokine response to brominated diphenyl ether-47 in the HTR-8/SVneo human first trimester extravillous trophoblast cell line

Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants, and BDE-47 is a prevalent PBDE congener detected in human tissues. Exposure to PBDEs has been linked to adverse pregnancy outcomes in humans. Although the underlying mechanisms of adverse birth outcomes are poorly understood, critical roles for oxidative stress and inflammation are implicated. The present study investigated antioxidant responses in a human extravillous trophoblast cell line, HTR-8/SVneo, and examined the role of nuclear factor E2-related factor 2 (Nrf2), an antioxidative transcription factor, in BDE-47-induced inflammatory responses in the cells. Treatment of HTR-8/SVneo cells with 5, 10, 15, and 20μM BDE-47 for 24h increased intracellular glutathione (GSH) levels compared to solvent control. Treatment of HTR-8/SVneo cells with 20μM BDE-47 for 24h induced the antioxidant response element (ARE) activity, indicating Nrf2 transactivation by BDE-47 treatment, and resulted in differential expression of redox-sensitive genes compared to solvent control. Pretreatment with tert-butyl hydroquinone (tBHQ) or sulforaphane, known Nrf2 inducers, reduced BDE-47-stimulated IL-6 release with increased ARE reporter activity, reduced nuclear factor kappa B (NF-κB) reporter activity, increased GSH production, and stimulated expression of antioxidant genes compared to non-Nrf2 inducer pretreated groups, suggesting that Nrf2 may play a protective role against BDE-47-mediated inflammatory responses in HTR-8/SVneo cells. These results suggest that Nrf2 activation significantly attenuated BDE-47-induced IL-6 release by augmentation of cellular antioxidative system via upregulation of Nrf2 signaling pathways, and that Nrf2 induction may be a potential therapeutic target to reduce adverse pregnancy outcomes associated with toxicant-induced oxidative stress and inflammation.

Biological roles of fungal carotenoids

Carotenoids are terpenoid pigments widespread in nature, produced by bacteria, fungi, algae and plants. They are also found in animals, which usually obtain them through the diet. Carotenoids in plants provide striking yellow, orange or red colors to fruits and flowers, and play important metabolic and physiological functions, especially relevant in photosynthesis. Their functions are less clear in non-photosynthetic microorganisms. Different fungi produce diverse carotenoids, but the mutants unable to produce them do not exhibit phenotypic alterations in the laboratory, apart of lack of pigmentation. This review summarizes the current knowledge on the functional basis for carotenoid production in fungi. Different lines of evidence support a protective role of carotenoids against oxidative stress and exposure to visible light or UV irradiation. In addition, the carotenoids are intermediary products in the biosynthesis of physiologically active apocarotenoids or derived compounds. This is the case of retinal, obtained from the symmetrical oxidative cleavage of β-carotene. Retinal is the light-absorbing prosthetic group of the rhodopsins, membrane-bound photoreceptors present also in many fungal species. In Mucorales, β-carotene is an intermediary in the synthesis of trisporoids, apocarotenoid derivatives that include the sexual hormones the trisporic acids, and they are also presumably used in the synthesis of sporopollenin polymers. In conclusion, fungi have adapted their ability to produce carotenoids for different non-essential functions, related with stress tolerance or with the synthesis of physiologically active by-products.

Gene expression in snapbeans exposed to ozone and protected by ethylenediurea

Ethylenediurea (EDU) is the most common chemical used to prevent ozone (O3) injury on vegetation. Despite considerable research, its mode of action remains elusive and gene expression has not been studied. Transcripts of major antioxidant enzymes (catalase, glutathione reductase, glutathione peroxidase) were measured for the first time in a model plant (Phaseolus vulgaris cv S156) after short-term O3 exposure (0 or 90 ppb, 5 h/d, 4 days) and a single spray with EDU (0 or 300 ppm). Visible, physiological and biochemical parameters were assessed as indices of O3-induced stress. In O3-exposed EDU-protected plants, levels of transcript, enzyme activity, H2O2 accumulation, gas exchange and foliar visible injury were similar to those in control plants. These results suggest that EDU may halt the O3-induced ROS generation within 24 h from the exposure, and thus the downstream cascade mechanisms leading to increased H2O2 production, impaired gas exchange, and occurrence of leaf lesions.

[Different types of obesity. Can some types of obesity be protective?]

Adipose tissue is not to be treated as a homogenous organ of identical functionality. Adipose tissue can be divided into specific regions of different localizations with adipocytes differing in their genetical profile, metabolism, autophagic activity and capacity for multiplication - hyperplasia. Visceral and ectopic regions of adipose tissue are characterized by poor capilarization, hypoxia, and the presence of hypertrophic big adipocytes. Adipocytes of these regions show limited inherent capacity for hyperplasia and when exposed for over nutrition are undergoing disruption with consecutive autophagy and macrophage infiltration leading to development of inflammatory conditions as well as increased fibrosis and remodeling of extracellular matrix. Comparatively smaller numerous adipocytes of gluteo-femoral regions are characterized by better insulin sensitivity and ability to buffer the excess of fatty acids preventing lipotoxemia and to react by hyperplasia when exposed to calorie excess. The differences between these two types of adipocytes with different genetic profile and metabolism are parallel with different localization of these two types of adipocytes and are responsible for the difference in pathophysiology between abdominal and gluteofemoral adiposity. The large body of evidence indicates that hypertrophic and hyperplastic obesity correspond to abdominal and gluteophemoral type of obesity and explain the differences in their pathophysiology and comorbidities.

Elevated CO₂ ameliorated the adverse effect of elevated O₃ in previous-year and current-year needles of Pinus tabulaeformis in urban area

The effects of elevated CO2 (700 ppm) and/or elevated O3 (80 ppb) on different-age needles of Pinus tabulaeformis were studied in open top chambers. Elevated CO2 increased needle dry weight, net photosynthetic rate, and maximum quantum yield of photosystem II in previous and current-year needles. Elevated O3 significantly decreased dry weight, net photosynthetic rate, and maximum quantum yield of photosystem II only in previous-year needles. Elevated O3 increased hydrogen and malondialdehyde content in previous-year needles, but did not significantly increase hydrogen peroxide content in current-year needles, which indicated that oxidative stress induced by elevated O3 was more severe in previous-year needles than in current-year needles. Our results showed that the adverse effect of elevated O3 in needles of P. tabulaeformis was ameliorated by elevated CO2.

Soya phospholipid complex of mangiferin enhances its hepatoprotectivity by improving its bioavailability and pharmacokinetics

BACKGROUND

Mangiferin is a xanthonoid present in Mangifera indica. It has been reported for a variety of pharmacological activities, including hepatoprotection. However, the major disadvantage of mangiferin is its reduced biological activity due to poor absorption, low bioavailability and rapid elimination from the body after administration. The aim of this study was to prepare a phospholipid complex of mangiferin to overcome these limitations and to investigate the impact of the complex on hepatoprotective activity and bioavailability.

RESULTS

The results showed that the complex has an enhanced hepatoprotective and in vivo antioxidant activity as compared to pure mangiferin at the same dose level (30 and 60 mg kg⁻¹). The complex restored the levels of serum hepatic marker enzymes and liver antioxidant enzymes with respect to carbon tetrachloride-treated animals. The complex also increased the bioavailability of mangiferin in rat serum by 9.75-fold compared to pure mangiferin at the same dose level and enhanced the elimination half-life (t(1/2 el)) from 1.71 ± 0.12 h⁻¹ to 3.52 ± 0.27 h⁻¹.

CONCLUSION

The results suggested that the complexation of mangiferin with soya phospholipid enhanced the hepatoprotection and in vivo antioxidant activity, which may be due to the improved bioavailability and pharmacokinetics of mangiferin in rat serum.

CENTRAL NEUROENDOCRINE MECHANISMS OF GASTROPROTECTION

Selye recognized the importance of activation of hypothalamic-pituitary-adrenal axis during stress and the connection between central nervous system and neuroendocrine regulation. This concept basically contributed to initiation of the studies, which revealed the importance of brain gut axis in regulation of gastric mucosal integrity. Several neuropeptides, such as thyreotrop releasing hormones, adrenomedullin, peptide YY, amylin, opioid peptides, nociceptin, nocisatin, substance P, ghrelin, leptin, orexin-A, angiotensin II were shown to induce gastroprotective effect injected centrally. Though the involvement of dorsal vagal complex and vagal nerves in conveying the central action to the periphery has been well documented, additional mechanisms have also been raised. The interaction between neuropeptides further component that may modify the gastric mucosal resistance to noxious stimulus.

THE SURPRISING DUAL ACTION OF GLUCOCORTICOIDS

Glucocorticoid hormones may have dual action on the stomach: physiological gastroprotective and pathological proulcerogenic one. In physiological conditions, even in acute stress situations, glucocorticoids have an adaptive effect on the stomach and, therefore, are gastroprotective. The findings that we review in this article suggest that glucocorticoids released during acute stress are naturally occurring protective factors that play an important role in maintenance of the gastric mucosal integrity.

Novel insights into the cardio-protective effects of FGF21 in lean and obese rat hearts

Aims

Fibroblast growth factor 21 (FGF21) is a hepatic metabolic regulator with pleotropic actions. Its plasma concentrations are increased in obesity and diabetes; states associated with an increased incidence of cardiovascular disease. We therefore investigated the direct effect of FGF21 on cardio-protection in obese and lean hearts in response to ischemia.

Methods and Results

FGF21, FGF21-receptor 1 (FGFR1) and beta-Klotho (βKlotho) were expressed in rodent, human hearts and primary rat cardiomyocytes. Cardiac FGF21 was expressed and secreted (real time RT-PCR/western blot and ELISA) in an autocrine-paracrine manner, in response to obesity and hypoxia, involving FGFR1-βKlotho components. Cardiac-FGF21 expression and secretion were increased in response to global ischemia. In contrast βKlotho was reduced in obese hearts. In isolated adult rat cardiomyocytes, FGF21 activated PI3K/Akt (phosphatidylinositol 3-kinase/Akt), ERK1/2(extracellular signal-regulated kinase) and AMPK (AMP-activated protein kinase) pathways. In Langendorff perfused rat [adult male wild-type wistar] hearts, FGF21 administration induced significant cardio-protection and restoration of function following global ischemia. Inhibition of PI3K/Akt, AMPK, ERK1/2 and ROR-α (retinoic-acid receptor alpha) pathway led to significant decrease of FGF21 induced cardio-protection and restoration of cardiac function in response to global ischemia. More importantly, this cardio-protective response induced by FGF21 was reduced in obesity, although the cardiac expression profiles and circulating FGF21 levels were increased.

Conclusion

In an ex vivo Langendorff system, we show that FGF21 induced cardiac protection and restoration of cardiac function involving autocrine-paracrine pathways, with reduced effect in obesity. Collectively, our findings provide novel insights into FGF21-induced cardiac effects in obesity and ischemia.

[The receptorial responsiveness method (RRM): a new possibility to estimate the concentration of pharmacologic agonists at their receptors]

Cardiovascular disease is the biggest challenge in terms of life expectancy in developed countries. Adenosine contributes to the adaptation of the heart to ischemia and hypoxia, because adenosine, in addition to its metabolite role in the nucleic acid metabolism, is the endogenous agonist of the ubiquitous adenosine receptor family. Adenosine receptor activation is beneficial in most cases, it improves the balance between energy supply and consumption, reduces injury caused by stressors and inhibits the unfavorable tissue remodeling. Pharmacological manipulation of cardioprotective effects evoked by adenosine is an important, although to date not sufficiently utilized endeavor that may have therapeutic and preventive implications in cardiovascular diseases. As the ligand binding site of adenosine receptors is accessible from the extracellular space, it is especially important to know the adenosine concentration of the interstitial fluid ([Ado](ISF)). However, in the functioning heart, [Ado](ISF) values range in an extremely wide interval, spanning from nano- to micromolar concentrations, as estimated by the commonly used methods. Our recently developed procedure, the receptorial responsiveness method (RRM), may resolve this problem in certain cases. RRM enables quantification of an acute increase in the concentration of a pharmacological agonist, uniquely in the microenvironment of the receptors of the given agonist. As a limitation, concentration of agonists with short half-life (just like adenosine) at their receptors can only be quantified with the equieffective concentration of a stable agonist exerting the same action. In a previous study using RRM, inhibition of the transmembrane nucleoside transport in the euthyroid guinea pig atrium produced an increase in [Ado](ISF) that was equieffective with 18.8 +/- 3 nM CPA (N6-cyclopentyladenosine, a stable, selective A1 adenosine receptor agonist). This finding is consistent with observations of others, i.e., in the normoxic heart, adenosine flow is directed into the cell interior, and thus transport blockade elevates the extracellular adenosine level. In turn, nucleoside transport inhibition in the hyperthyroid guinea pig atrium caused a rise in [Ado](ISF) equieffective with 46.5 +/- 13.7 nM CPA. In sum, our work team was the first to demonstrate that adenosine transport in the hyperthyroid atrium has the same direction but is more intense as/than that in the euthyroid one.

[Experimental study of pinostrobine oxime biotransformation]

We have experimentally studied pathways of elimination of an oximized derivative of phytoflavonoid pinostrobine by HPLC/mass spectrometry. Four potential metabolites of pinostrobine oxime have been found and there was an attempt to determine their molecular structures on the basis of their fragmentation under positive electrospray ionization conditions. It is established that pinostrobine oxime is removed from the organism mainly unchanged and also in the form of glucuronated derivative.

Multiple protective functions of sigma1 receptor

The Sigma Receptor 1 (sig-1R) is a protein present in numerous normal tissues, such as brain, retina, lens, liver, lung, heart, but also in many tumor lines. Its amino acid sequence is homologous to fungal C-8,7 sterol isomerase, but it has no known homology with mammalian proteins and does not possess sterol isomerase activity. It is localized in plasma and ER membranes, and its exact function is not clarified as of yet. Last reports point to its participation in regulation of ionic channels activity, particularly calcium channels. Application of numerous synthetic ligands of sigma1 receptor provided means to study its protective effects and metabolic functions in different tissues. This review describes influence of sigma1 receptor on various aspects of cellular metabolism, such as calcium signalling, mitochondrial functions, oxidative stress, survival and apoptotic pathways, and tumor cells proliferation.

Sunlight, vitamin D and malignant melanoma: an update

Solar radiation represents an essential requirement for life, not only by spending the thermal energy for photosynthesis in plants, which provides our atmosphere with oxygen, but also by facilitating the cutaneous synthesis of vitamin D in vertebrates and many other organisms. It is well known that humans and most vertebrates have to obtain an adequate source of vitamin D, in order to develop and maintain a healthy mineralized skeleton and in order to be protected against cancer and a broad variety of other diseases. On the other hand, solar UV radiation can be assumed to be the most relevant environmental carcinogen causing melanoma and nonmelanoma skin cancer with increasing incidences. During the last decades, epidemiological studies and experimental animal models, including genetically engineered mice, the Xiphophorus hybrid fish, the south american oppossum and human skin xenografts, have further elucidated the multi-step process of UV-induced melanomagenesis. It has to be emphasized that, in contrast to intermittent, short-term high-dose solar UV-exposure, more chronic less intense exposure (which is recommended by many experts in the field to obtain a sufficient vitamin D status) has not been found to be a risk factor for the development of melanoma and in fact has been found in several studies to be protective. Interestingly, several independent lines of investigation have demonstrated convincing evidence that vitamin D and/or analogs may be effective in the prevention and treatment of melanoma. This essay summarizes our present understanding about the pathogenic role of UV radiation and of vitamin D for malignant melanoma.

Pharmacological evaluation of mangiferin herbosomes for antioxidant and hepatoprotection potential against ethanol induced hepatic damage

CONTEXT

Fatty liver is the first stage of alcoholic damage which is reversible with abstinence from alcohol. Mangiferin (MF) showed potent scavenging activity on diphenyl-1-picrylhydrazyl radicals which stimulate liver regeneration in various liver injuries.

OBJECTIVE

Although, MF shows hepatoprotection against various liver disorders but due to rapid clearance and limited solubility in lipoid environment, there is problem of its poor absorption from intestine hence poor bioavailability. Owing to which there is a need to develop MF herbosomes to resolve the problem of poor bioavailability to enhance the therapeutic potential.

METHODS

Successfully prepared MF herbosomes through complexation with phospholipids were characterized by physicochemical, chromatography, spectroscopy (differential scanning calorimetry (DSC), infrared (IR), and nuclear magnetic resonance (NMR)), ex vivo absorption using everted small intestine sac technique and in vivo studies using ethanol inducing hepatotoxicity in albino rats and comparing the results against plain MF.

RESULTS

Ex vivo study showed significant increased absorption of MF from prepared MF herbosomes as compared to plain MF. The hepatoprotective potential of MF herbosomes evaluated by in vivo study revealed significantly decreased levels of serum glutamate oxaloacetate transminase (SGOT), serum glutamate pyruvate transminase (SGPT), total bilirubin, and alkaline phosphatase (ALP) in MF herbosomes as compared to plain MF. MF herbosomes also showed significantly decreased level of malonyl dehydrogenase along with increased levels of reduced glutathione, superoxide dismutase (SOD) and catalase as compared to plain MF which was also comparable to the standard drug, silymarin (SL).

CONCLUSION

The above mentioned results showed that hepatoprotective and antioxidant potency of MF enhanced due to the preparation of its herbosomes.

Protective effect of edible marine algae, Laminaria japonica and Porphyra haitanensis, on subchronic toxicity in rats induced by inorganic arsenic

Arsenic, a potent environmental toxic agent, causes various hazardous effects on human health. This study was performed to evaluate the protective effects of edible marine algae, Laminaria japonica and Porphyra haitanensis, on subchronic stress of rats induced by arsenic trioxide (As2O3). The co-treatment of marine algae could slightly increase the growth rates of body weights compared to the As2O3-treated group. The marine algae application restored liver and renal function by preventing the increment in the activities of alanine transaminase and alkaline phosphatase, and the levels of total protein, blood urea nitrogen, and creatinine. The increase in the contents of total cholesterol, triglyceride, and low density lipoprotein cholesterol, and decrease in the contents of high density lipoprotein cholesterol were observed in algae co-treated groups which indicated that marine algae could reverse the abnormal lipid metabolisms induced by arsenic. Moreover, these algae could protect the rats from lipid peroxidation by restoring the depletion of superoxide dismutase and glutathione peroxidase activities and sulfhydryl group contents, and lowering the enhanced malondialdehyde contents. Therefore, evidences indicate that L. japonica and P. haitanensis can serve as an effective regimen for treating arsenic poisoning.

Vitamin C: electron emission, free radicals and biological versatility

The many-sided biological role of vitamin C (ascorbate) is briefly illustrated by specific examples. It is demonstrated that in aqueous solutions, vitamin C emits solvated electrons (e(aq)(-)), when excited in single state. Vitamin C can also react with e(aq)(-) as well as transfer them to other biological systems and thereby acts as efficient electron mediator. Based on its chemical and biological properties, it is clear that vitamin C plays a very important role in various functions in the organism alongside biochemical processes.

[IL28B CC genotype: a protective factor and predictor of the response to interferon treatment in chronic hepatitis C virus infection]

INTRODUCTION

In chronic hepatitis C-virus infection the possible role of gene variants encoding cytokines has become the focus of interest.

AIM

The aim of the study was to investigate the effect of IL28B polymorphisms on the outcome of chronic hepatitis C-virus genotype 1 infection in the Hungarian population. In addition, the association between IL28B genotypes and the Th1/Th2 cytokine production of activated peripheral blood monocytes and lymphocytes was evaluated.

METHOD

Total of 748 chronic hepatitis C-virus genotype 1 positive patients (365 males and 383 females, aged between 18 and 82 years; mean age, 54±10 years) were enrolled, of which 420 patients were treated with pegylated interferon plus ribavirin for 24-72 weeks. Of the 420 patients, 195 patients (46.4%) achieved sustained virological response. The IL28B rs12979860 polymorphism was determined using Custom Taqman SNP Genotyping Assays (Applied Biosystems, Life Technologies, Foster, CA, USA). For cytokine studies, tumour necrosis factor-α, interleukin-2, interferon-γ, interleukin-2 and interleukin-4 production by LPS-stimulated monocytes and PMA-ionomycine activated lymphocytes were measured from the supernatant of the cells obtained from 40 hepatitis C-virus infected patients, using FACS-CBA Becton Dickinson test. The cytokine levels were compared in patients with different (CC, CT, TT) IL28B genotypes.

RESULTS

The IL28B rs12979860 CC genotype occurred in lower frequency in hepatitis C-virus infected patients than in healthy controls (26.1% vs 51.4%, OR 0.333, p<0.001). Patients carried the T allele with higher frequency than controls (73.9%, vs 48.6%, OR 3.003, p<0.001). Pegylated interferon plus ribavirin treated patients with the IL28B CC genotype achieved higher sustained virological response rate than those with the CT genotype (58.6% vs 40.8%, OR 2.057, p = 0.002), and those who carried the T allele (41.8%, OR1.976, p = 0.002). LPS-induced TLR-4 activation of monocytes resulted in higher tumour necrosis factor-α production in patients with the IL28B CC genotype compared to non-CC individuals (p<0.01). Similarly, increased tumour necrosis factor-α, interleukin-2 and interferon-γ production by lymphocytes was found in the IL28B CC carriers (p<0.01) CONCLUSIONS: The IL28B CC genotype exerts protective effect against chronic hepatitis C-virus infection and may be a pretreatment predictor of sustained virological response during interferon-based antiviral therapy. The IL28B CC polymorphism is associated with increased Th1 cytokine production of activated peripheral blood monocytes and lymphocytes, which may play a role in interferon-induced rapid immune control and sustained virological response of pegylated interferon plus ribavirin treated patients.

Esophagoprotection mediated by exogenous and endogenous melatonin in an experimental model of reflux esophagitis

Reflux esophagitis is a common clinical entity in western countries with approximately 30% of the population experiencing the symptoms at least once every month. The imbalance between the protective and aggressive factors leads to inflammation and damage of the esophageal mucosa. We compared the effect of exogenous melatonin and melatonin derived endogenously from L-tryptophan with that of pantoprazole or ranitidine in acid reflux esophagitis due to ligation of the rat pylorus and the limiting ridge between the forestomach and the corpus. Four hours after the induction of gastric reflux, an increase in mucosal lesions associated with edema of the submucosa and with the infiltration of numerous neutrophils and the fall in esophageal blood flow (EBF) were observed. Both melatonin and L-tryptophan or pantoprazole significantly reduced the lesion index (LI) and raised the EBF. Pinealectomy that significantly decreased plasma melatonin levels aggravated LI and these effects were reduced by melatonin and L-tryptophan. Luzindole, the MT2 receptor antagonist, abolished the melatonin-induced reduction in LI and the rise in EBF. L-NNA and capsaicin that augmented LI and decreased EBF, also significantly reduced melatonin-induced protection and hyperemia; both were restored with L-arginine and calcitonin gene-related peptide (CGRP) added to melatonin. Upregulation of IL-1β and TNF-α mRNAs and plasma IL-1β and TNF-α levels were significantly attenuated by melatonin and L-tryptophan. We conclude that melatonin protects against acid reflux-induced damage via activation of MT2 receptors mediated by NO and CGRP released from sensory nerves and the suppression of expression and release of TNF-α and IL-1β.

Protective activity of hydroxytyrosol metabolites on erythrocyte oxidative-induced hemolysis

The capacity of important hydroxytyrosol metabolites (homovanillyl alcohol, hydroxytyrosol acetate, homovanillyl alcohol acetate, hydroxytyrosol 3' and 4'-O-glucuronides, and homovanillyl alcohol 4'-O-glucuronide) to protect red blood cells (RBCs) from oxidative injury induced by the radical initiator 2,2'-azo-bis(2-amidinopropane) dihydrochloride (AAPH) or by the natural radical initiator H2O2 was evaluated. In the presence of AAPH, all compounds showed to protect RBCs from hemolysis in a dose-dependent manner, exccept for the homovanillyl alcohol glucuronide, with the order of activity being at 20 μM hydroxytyrosol > hydroxytyrosol glucuronides = hydroxytyrosol acetate = homovanillyl alcohol = homovanillyl acetate > homovanillyl alcohol glucuronide. At 10 μM, hydroxytyrosol, hydroxytyrosol acetate, and hydroxytyrosol glucuronides still protected hemoglobine from oxidation and from morphological RBC changes. In the presence of H2O2, hydroxytyrosol showed to significantly protect RBCs from oxidative hemolysis in a dose-dependent manner, but the hydroxytyrosol glucuronides showed only a limited protection that was independent of the concentration used.

Identification of a hepatoprotective peptide in wheat gluten hydrolysate against D-galactosamine-induced acute hepatitis in rats

A hepatoprotective peptide, pyroglutamyl leucine (pyroGlu-Leu), was identified in wheat gluten hydrolysate through an in vivo activity-guided fractionation approach based on D-galactosamine-induced acute hepatitis in rats and fractionation of peptides with large-scale preparative ampholine-free isoelectric focusing. The active acidic fraction predominantly consisted of pyroglutamyl peptides and free pyroglutamic acid. Pyroglutamyl peptides were derivatized with phenyl isothiocyanate after removal of a pyroglutamyl residue by pyroglutamate aminopeptidase. The derivatives were purified by reversed-phase HPLC and subjected to sequence analysis. The active fraction contained pyroGlu-Ile, pyroGlu-Leu, pyroGlu-Gln, pyroGlu-Gln-Gln, and free pyroGlu. Ingestion of pyroGlu-Leu at 20 mg/kg body weight significantly decreased serum aspartate and alanine aminotransferases to approximately 30% and 20% of those values of the vehicle group, respectively, which were near the normal levels. Thirty minutes after ingestion of pyroGlu-Leu at 20 mg/kg, the concentration of pyroGlu-Leu in portal blood plasma increased to approximately 2 μM.

Adiponectin prevents islet ischemia-reperfusion injury through the COX2-TNFα-NF-κB-dependent signal transduction pathway in mice

Islets are exceptionally susceptible to ischemia-reperfusion injury, an increased incidence of primary graft nonfunctionality, and β-cell death during a transplant procedure. Therefore, islets require protection during the early stages of the transplant procedure. Based on the beneficial vascular and anti-inflammatory activity of adiponectin, we hypothesize that adiponectin protects islet cells against ischemia-reperfusion injury and graft dysfunction after transplantation. To examine the effects of adiponectin on the resistance of islet ischemia-reperfusion injury, we used the islet hypoxia-reoxygenation injury model and performed kidney subcapsular syngeneic islet transplants to assess the islets' vitality and function. Furthermore, we utilized lipopolysaccharide (LPS)-induced or tumor necrosis factor α (TNFα)-induced damage to islet cells to model the inflammation of post-transplant ischemia-reperfusion injury and transplanted islets in adiponectin knockout mice to explore whether the protective action of adiponectin is involved in TNFα production and nuclear transcription factor-κB (NF-κB) activation. Adiponectin suppressed TNFα production and IκB-α phosphorylation; decreased hypoxia-reoxygenation and LPS-induced and TNFα-induced islet apoptosis; and improved islet function in vivo and in vitro. Our results demonstrate that adiponectin protects the islet from injury. We show that islet protection occurs in response to ischemia-reperfusion and is dependent on the suppression of islet production by TNFα through cyclooxygenase 2 and the inhibition of the TNFα-induced NF-κB activation pathways.

IL-22 in tissue-protective therapy

IL-22, a member of the IL-10 cytokine family, has recently gained significant attention as a protective agent in murine models of diseases driven by epithelial injury. Like its biochemical and functional sibling IL-10, IL-22 elicits cellular activation primarily by engaging the STAT3 signalling pathway. Exclusively produced by leukocytes, but targeting mostly cells of epithelial origin, IL-22 has been proposed as a specialized cytokine messenger acting between leukocytic and non-leukocytic cell compartments. A lack of response in leukocytes to IL-22 mirrors tightly controlled IL-22 receptor expression and probably explains the apparent lack of instant adverse effects after systemic IL-22 administration to mice. Anti-apoptotic, pro-proliferative and pro-regenerative characteristics the major biological properties of this cytokine. Specifically, application of IL-22 is associated with tissue protection and/or regeneration in murine models of infection/microbe-driven inflammation at host/environment interfaces, ventilator-induced lung injury, pancreatitis and liver damage. Overall, preclinical studies would support therapeutic administration of seemingly well-tolerated recombinant IL-22 for treatment of an array of acute diseases manifested in epithelial tissues. However, the feasibility of prolonged administration of this cytokine is expected to be restricted by the tumourigenic potential of the IL-22/STAT3 axis. IL-22, moreover, apparently displays an inherent context-specific capacity to amplify distinct aspects of autoimmune inflammation. Here, the prospects, expectations and restrictions of IL-22 administration in tissue-protective therapy are discussed.

Analysis of CD45- [CD34+/KDR+] endothelial progenitor cells as juvenile protective factors in a rat model of ischemic-hemorrhagic stroke

Background

Identification of juvenile protective factors (JPFs) which are altered with age and contribute to adult-onset diseases could identify novel pathways for reversing the effects of age, an accepted non-modifiable risk factor to adult-onset diseases. Since endothelial progenitor cells (EPCs) have been observed to be altered in stroke, hypertension and hypercholesterolemia, said EPCs are candidate JPFs for adult-onset stroke. A priori, if EPC aging plays a ‘master-switch JPF-role’ in stroke pathogenesis, juvenile EPC therapy alone should delay stroke-onset. Using a hypertensive, transgenic-hyperlipidemic rat model of spontaneous ischemic-hemorrhagic stroke, spTg25, we tested the hypothesis that freshly isolated juvenile EPCs are JPFs that can attenuate stroke progression and delay stroke onset.

Methodology/Principal Findings

FACS analysis revealed that cd45- [cd34+/kdr+] EPCs decrease with progression to stroke in spTg25 rats, exhibit differential expression of the dual endodthelin-1/VEGFsp receptor (DEspR) and undergo differential DEspR-subtype specific changes in number and in vitro angiogenic tube-incorporation. In vivo EPC infusion of male, juvenile non-expanded cd45-[cd34+/kdr+] EPCs into female stroke-prone rats prior to stroke attenuated progression and delayed stroke onset (P<0.003). Detection of Y-chromosome DNA in brain microvessels of EPC-treated female spTg25 rats indicates integration of male EPCs into female rat brain microvessels. Gradient-echo MRI showed delay of ischemic-hemorrhagic lesions in EPC-treated rats. Real-time RT-PCR pathway-specific array-analysis revealed age-associated gene expression changes in cd45-[cd34+/kdr]EPC subtypes, which were accelerated in stroke-prone rats. Pro-angiogenic genes implicated in intimal hyperplasia were increased in stroke-prone rat EPCs (P<0.0001), suggesting a maladaptive endothelial repair system which acts like a double-edged sword repairing while predisposing to age-associated intimal hyperplasia.

Conclusions/Significance

Altogether, the data demonstrate that cd45-[cd34/kdr+]EPCs are juvenile protective factors for ischemic hemorrhagic stroke as modeled in the spTg25-rat model. The ability to delay stroke onset emphasizes the importance of EPC-mediated roles in vascular health for ischemic-hemorrhagic stroke, a high unmet need.

[Milk phospholipids as nutraceutic]

Almost the all milk fat is closed inside fat globules possessing envelope of phospholipids, glycosphingolipids, cholesterols and proteins. Phospholipids of milk are composed of phosphatidylcholine (lecithin), phosphatidylethanolamine (kefalin), sphingomyelin, also phosphatidylinositol, phosphatidylserine and lizophosphatidylcholine (lizolecithin) and make 30% of the milk fat globule membrane. Phospholipids possess pro-health properties. They act neuroprotectively, regulate brain activity, improve memory and resistance to stress, reduce depression risk, Alzheimer and Parkinson diseases. Due to participation in molecular transport, they influence cell growth and development, speed up organism regeneration after great physical effort. The phospholipids limit cholesterol absorption from gastrointestinal tract, are effective in liver therapy (steatosis, alcohol intoxication). Moreover, they are inhibitors of proinflammation factors, pathogens of alimentary canal and cancers (e.g. of colon and adenoma). Alkiloglycerphospholipids - unique component of milk fat - stimulate immune system and protect tissues against toxic action of hydroxyl radicals that is generated during radiotherapy.

Zinc inhibits apoptosis and maintains NEP downregulation, induced by ropivacaine, in HaCaT cells

Zinc (Zn), a cell-protective metal against various toxic compounds, is the key agent for neutral endopeptidase (NEP) functional structure. NEP is a zinc metalloenzyme which degrades endogenous opioids and is expressed in human keratinocytes (HaCaT). Ropivacaine, a widely used opiate local anaesthetic, exerts cell toxic and apoptotic effects against HaCaT cells. The aim of the present study is to investigate whether zinc modulates the effects of ropivacaine on proliferation, viability, apoptosis and NEP expression in HaCaT cells. To investigate the role of ropivacaine in NEP function, HaCaT cells overexpressing NEP were generated via cell transfection with plasmids carrying NEP cDNA. Ropivacaine's anti-proliferative effect was tested by Neubauer's chamber cell counting, and induction of cell death was demonstrated by trypan blue exclusion assay. Apoptosis due to ropivacaine was tested via DNA fragmentation and poly-ADP-ribose-polymerase (PARP) cleavage. NEP and PARP expression was performed by western blot analysis. Results showed that zinc (15 μΜ) inhibited proliferation and cell death induction by ropivacaine (0.5, 1 and 2 mM) (p < 0.05) as well as apoptosis induced by the drug (0.5 and 1 mM) in HaCaT cells. Ropivacaine (1.0, 2.0 and 5.0 mM) downregulated NEP expression in the presence of zinc (15 μΜ) while NEP overexpression enhanced ropivacaine's apoptotic effect. In conclusion, the abilities of zinc to inhibit the toxic and apoptotic effects of ropivacaine, to maintain NEP downregulation induced by the drug and, consequently, to enhance its anaesthetic result suggest that zinc may have a significant role in pain management and tissue protection.

Effects of selenium supplementation on expression of endothelin-1 and its receptors in pulmonary microvascular endothelial cells from chick embryos

The objective of this study was to evaluate the effects of supplemental selenium (Se) on expression of endothelin-1 (ET-1) and its receptors in cultured chick embryos pulmonary microvascular endothelial cells (PMVECs). To accomplish this, PMVECs were treated in Se-deficient or Se-supplement (12, 24, 50, 100 ng/ml) culture medium for 48 h. Low Se medium was achieved by reducing serum concentrations and the essential growth factors were added. After the incubation, the effects of supplemental Se on ET-1 and its receptors gene expression were assessed by quantitative real-time PCR (qRT-PCR). Compared with the control group, our results showed that among the different concentrations of Se supplement, the levels of ET-1 gene expression treated with both the moderate Se doses (24, 50 ng/ml, P < 0.01, P < 0.01, respectively) and the high doses (100 ng/ml, P < 0.05) were noticeably decreased, the low-dose group (12 ng/ml), which showed no changes. Meanwhile, Se supplement (24, 50, 100 ng/ml) was found to be effective in reducing the expression levels of ETA (P < 0.01, P < 0.05, P < 0.05, respectively) in cultured PMVECs grown in low Se medium. However, there were no significant changes (P > 0.05) in ETB mRNA levels during the cell proliferation. These observations indicated that Se may play both direct and indirect role in the regulation of ET-1 and its receptors gene expression and their production in avian PMVECs. Se supplement decreases in ET-1 and ETA production in Se-deficient PMVECs may partly explain the mechanism of the protective effects of the Se on the cardiovascular system.

Foreign RNA induces the degradation of mitochondrial antiviral signaling protein (MAVS): the role of intracellular antiviral factors

Mitochondrial antiviral signaling protein (MAVS) is an essential adaptor molecule that is responsible for antiviral signaling triggered by retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs), leading to the induction of type I interferon in innate immunity. Previous studies have shown that certain viruses evade the innate immune response by cleaving the MAVS protein. However, little is known about how MAVS is regulated in response to foreign RNA, including both single-stranded (ss) and double-stranded (ds) RNA, because most previous reports have shown that the cleavage of MAVS is executed by proteases that are induced or activated by the invading RNA viruses. Here, we report that MAVS mRNA is degraded in response to polyinosinic-polycytidylic acid (polyI:C), a synthetic dsRNA, in A549 cells. RNA interference (RNAi) experiments revealed that both ssRNA- and dsRNA-associated pattern-recognition receptors (PRRs) were not involved in the degradation of MAVS mRNA. Foreign RNA also induced the transient degradation of the MAVS protein. In the resting state, the MAVS protein was protected from degradation by interferon regulatory factor 3 (IRF3); moreover, the dimerization of IRF3 appeared to be correlated with the rescue of protein degradation in response to polyI:C. The overexpression of MAVS enhanced interferon-β (IFN-β) expression in response to polyI:C, suggesting that the degradation of MAVS contributes to the suppression of the hyper-immune reaction in late-phase antiviral signaling. Taken together, these results suggest that the comprehensive regulation of MAVS in response to foreign RNA may be essential to antiviral host defenses.

Peptide isolated from Japanese flounder skin gelatin protects against cellular oxidative damage

Gelatin was extracted from the skin of Japanese flounder ( Palatichtys olivaceus ) and was subjected to enzymatic hydrolysis. The peptic hydrolysate resulted in a potent antioxidative peptide Gly-Gly-Phe-Asp-Met-Gly (582 Da), which bears +12.61 kcal/mol hydrophobicity. The antioxidative potential of the peptide was characterized by analyzing the protective effect of the peptide on reactive oxygen species (ROS)-mediated intracellular macromolecule damage. It was found that the peptide is a potent scavenger of intracellular ROS, thereby protecting the radical-mediated damage of membrane lipids, proteins, and DNA. Moreover, the peptide is capable of upregulating the expression of inherent antioxidative enzymes, superoxide dismutase-1, glutathione, and catalase. Collectively, it can be concluded that Japanese flounder skin, a processing byproduct of filleting, can be effectively used to produce a bioactive peptide with potent antioxidant capacity.

Protection by polyphenols of postprandial human plasma and low-density lipoprotein modification: the stomach as a bioreactor

Recent studies dramatically showed that the removal of circulating modified low-density lipoprotein (LDL) results in complete prevention of atherosclerosis. The gastrointestinal tract is constantly exposed to food, some of it containing oxidized compounds. Lipid oxidation in the stomach was demonstrated by ingesting heated red meat in rats. Red wine polyphenols added to the rats' meat diet prevented lipid peroxidation in the stomach and absorption of malondialdehyde (MDA) in rat plasma. In humans, postprandial plasma MDA levels rose by 3-fold after a meal of red meat cutlets. MDA derived from meat consumption caused postprandial plasma LDL modification in human. The levels of plasma MDA showed a 75% reduction by consumption of red wine polyphenols during the meat meal. Locating the main biological site of action of polyphenols in the stomach led to a revision in the understanding of how antioxidants work in vivo and may help to elucidate the mechanism involved in the protective effects of polyphenols in human health.

[Cytotoxicity of lysomustine and its isomers, and their potential use for selection of cells]

N epsilon-Nitroso-N epsilon- [N'-(2-chloroethyl)carbamoyl]-L-lysine (I) and N epsilon- [N'-(2-chloroethyl)-N'-nitrosocarbamoyl]-L-lysine (II), the isomers being the constituents of antitumor agent Lysomustine, were obtained by RFHPLC. The study of cytotoxicity of the above compounds against K562 cells showed that the lesions induced by isomer (II) produce a significant cytotoxic effect but can be efficiently repaired by the action of MGMT (O6-methylaguanine DNA methyltransferase). Under similar conditions, the lesions induced by isomer (I) produce substantially smaller effect but are weakly if at all repairable by MGMT. The effects of a clinically approved agent Lysomustine, which is the mixture of isomers (I) and (II), are similar to those of isomer (II). The results obtained point to a different chemical nature of DNA lesions induced by two Lysomustine isomers. Our data indicate that Lysomustine and its isomer (II) can be used for in vitro selection of cells expressing MGMT.

Protection of riboflavin and UVB sensitized degradation of DNA and RNA bases by natural antioxidants

Riboflavin (RF) is a potent photosensitizer producing extensive degradation of purine and pyrimidine derivatives of nucleic acids under UVA, UVB and sunlight. In this study we have demonstrated that reactive O(2) species generated by photosensitized RF under UVB were responsible for the degradation of DNA and RNA bases. While (1)O(2) accounted for the degradation of adenine, guanine, thymine and uracil, O(2)(-·)also contributed to partial degradation of adenine. Cytosine remained unaffected by the synergistic action of RF and UVB. Ascorbic acid, glutathione, glycolic acid and quercetin showed remarkable protection (88-100%) against photodegradation of bases. Sorbitol was effective in preventing photodegradation of guanine. These naturally occurring antioxidants are potential candidates for prevention against oxidative stress caused by photosensitization.

Programmed cell death in plants: protective effect of tetraphenylphosphonium and tetramethylrhodamine cations used as transmembrane quinone carriers

Tetraphenylphosphonium (TPP(+)) and tetramethylrhodamine ethyl ester (TMRE(+)) cations used as transmembrane carriers of ubiquinone (MitoQ) and plastoquinone (SkQ, SkQR) in mitochondria prevented at nanomolar concentrations the chitosan- or H(2)O(2)-induced destruction of the nucleus in epidermal cells of epidermis isolated from pea leaves. The protective effect of the cations was potentiated by palmitate. Penetrating anions of tetraphenylboron (TB(-)) and phenyl dicarbaundecaborane also displayed protective effects at micromolar concentrations; the effect of TB(-) was potentiated by NH(4)Cl. It is proposed that the protective effect of the penetrating cations and anions against chitosan is due to suppression of the generation of reactive oxygen species in mitochondria as a result of the protonophoric effect of the cations plus fatty acids and the anions plus NH(4)(+). Phenol was suitable as the electron donor for H2O2 reduction catalyzed by horseradish peroxidase, preventing the destruction of cell nuclei. The penetrating cations and anions, SkQ1, and SkQR1 did not maintain the peroxidase or peroxidase/oxidase reactions measured by their suitability as electron donors for H(2)O(2) reduction or by the oxidation of exogenous NADH.

Protective effects of calcium on copper toxicity in Pelteobagrus fulvidraco: copper accumulation, enzymatic activities, histology

The present study was conducted to determine interactive effects of waterborne co-exposure of copper (Cu) and calcium (Ca) on Cu accumulation, enzymatic activities and histology in yellow catfish Pelteobagrus fulvidraco and test the prediction that Ca could protect against Cu--induced toxicity in the fish species. Yellow catfish were exposed to 0, 1.0, 2.0 mg Cu/l, in combination with 0 and 50 mg Ca/l. Waterborne Cu and Ca co-exposure influenced the majority of tested enzymatic activities (succinate dehydrogenase, malic dehydrogenase, lactate dehydrogenase, lipoprotein lipase and hepatic lipase), and changed Cu contents in several organs (gill, liver, kidney, gastrointestine and muscle). For histological observations, at the same Ca level, waterborne Cu exposure induced injuries in gills and liver. However, Ca addition seemed to mitigate the severity of Cu--induced injuries. Thus, our study demonstrated that Ca had the capacity to reduce Cu toxicity in P. fulvidraco.

Metabolite profiling of the moss Physcomitrella patens reveals evolutionary conservation of osmoprotective substances

The moss Physcomitrella patens is suitable for systems biology studies, as it can be grown axenically under standardised conditions in plain mineral medium and comprises only few cell types. We report on metabolite profiling of two major P. patens tissues, filamentous protonema and leafy gametophores, from different culture conditions. A total of 96 compounds were detected, 21 of them as yet unknown in public databases. Protonema and gametophores had distinct metabolic profiles, especially with regard to saccharides, sugar derivates, amino acids, lignin precursors and nitrogen-rich storage compounds. A hydroponic culture was established for P. patens, and was used to apply drought stress under physiological conditions. This treatment led to accumulation of osmoprotectants, such as altrose, maltitol, ascorbic acid and proline. Thus, these osmoprotectants are not unique to seed plants but have evolved at an early phase of the colonization of land by plants.

Synthesis, stability and pharmacological evaluation of a novel codrug consisting of lamivudine and ursolic acid

A novel codrug (LMX) was obtained from lamivudine (LMV) and ursolic acid (UA) coupled with ethyl chloroacetate through an amide and ester linkage. The structure of LMX was confirmed by ¹H NMR, ¹³C NMR, IR and HRMS. Herein, the in vitro non-enzymatic and enzymatic hydrolysis and in vivo pharmacological activities of LMX were studied. The kinetics of hydrolysis of LMX was studied in aqueous solution of pH 1-10, 80% buffered human plasma and in the presence of lipase from Porcine pancreas (EC 3.1.1.3) at 37°C. It is found that LMX hydrolysis rate was significantly faster in lipase with half-life of 1.4h compared to pH 7.4 phosphate buffer (t(1/2) 11.2h) and buffered human plasma (t(1/2) 5.4h). The decomposition rates in aqueous solution (pH 1-10) showed a U-shaped curve. LMX was comparatively stable between pH 3 and 6 (half-life >40 h). Pharmacological studies indicated that LMX had the dual action of anti-hepatitis B virus activity and hepatoprotective effects against acute liver injury. These findings suggest that LMX could be a promising candidate agent for the treatment of hepatitis.

Marine n-3 fatty acids alter the proteomic response to methylmercury in Atlantic salmon kidney (ASK) cells

Fish based diets have been linked to the amelioration of methylmercury (MeHg) induced symptoms in several epidemiological studies, particularly due to their contents of marine n-3 fatty acids. It has been suggested that n-3 fatty acids may mask the detrimental effects of MeHg due to their beneficial effect on the same biological functions which are negatively affected by MeHg. However, in vitro studies have implied that there may be direct interactions between the marine n-3 FAs and MeHg, which ameliorates MeHg toxicity through interactions at a biological level. To understand how marine n-3 FAs and MeHg interact in fish as a biological system, we wanted to investigate molecular interaction in a fish cell system. Atlantic salmon kidney (ASK) cells were pre-incubated with the marine n-3 FAs docosahexaenoic acid (22:6n-3, DHA) and eicosapentaenoic acid (20:5n-3, EPA) before exposing them to MeHg. Modulating effects of the marine FAs on MeHg toxicity were subsequently assessed using the exploratory technique of proteomics, in a factorial design. Thirty-four differentially regulated proteins were identified. From these; twenty-seven were shown to be differentially regulated by MeHg, twelve were regulated by the fatty acids, and another eight showed interaction effects between MeHg and the FAs. Several of the proteins were concomitantly affected by MeHg- and FA-main effects, as well as interaction effects. Functional annotations and pathway analysis of the proteins revealed that marine n-3 FAs and MeHg concurrently affected the abundance of protein markers relating to such molecular mechanisms as: cell signaling, calcium homeostasis, structural integrity, apoptosis, and energy metabolism. In conclusion, both marine n-3 FAs and MeHg can differentially affect the abundances of the same proteins, indicating modulating effects of EPA and DHA on MeHg metabolism, and possibly on its toxicity.

Inhibition of endogenous CO by ZnPP protects against stress-induced gastric lesion in adult male albino rats

Carbon monoxide (CO) has been found to be produced in every living cell in a biochemical reaction catalyzed by heme-oxygenase (HO) enzyme which degrades heme into biliverdin, CO, and iron. Endogenous CO is not a waste product, but acts as a chemical messenger mediating and modulating many intracellular biochemical reactions that regulate physiological functions. This study was designed to investigate the effect of inhibition of endogenous CO production by zinc protoporphyrin (ZnPP), an HO inhibitor, on the gastric secretion and ulceration induced by cold-restraint stress (CRS) in adult male albino rats. Rats were pylorically ligated and divided randomly into the following groups (six rats each): control, ZnPP treated (50 μmol/kg/day, s.c. for 10 days), CRS, and stressed ZnPP treated groups. Blood samples were collected from the retro-orbital sinus of anesthetized rats for determination of CO concentration. We found that ZnPP pretreatment significantly decreased HO-1 level, CO level, and volume of gastric juice as compared to the control non-stressed rats. In the present study, ZnPP pretreatment proved to be protective against development of ulcerative lesions in CRS model as evidenced by reduction of the ulcer index, and this could be mediated through reduction of free and total acidity of gastric secretion and decreased lipid peroxidation but with significantly decreased gastric protective nitric oxide and prostaglandin E(2) levels. In conclusion and according to our results, the protective effect of ZnPP on CRS-induced gastric ulcers despite of inhibition of endogenous CO could be attributed to the presence of zinc which is known to have a protective anti-ulcer effect.

Protection by Salvia extracts against oxidative and alkylation damage to DNA in human HCT15 and CO115 cells

DNA damage induced by oxidative and alkylating agents contributes to carcinogenesis, leading to possible mutations if replication proceeds without proper repair. However, some alkylating agents are used in cancer therapy due to their ability to induce DNA damage and subsequently apoptosis of tumor cells. In this study, the genotoxic effects of oxidative hydrogen peroxide (H₂O₂) and alkylating agents N-methyl-N-nitrosourea (MNU) and 1,3-bis-(2-chloroethyl)-1-nitosourea (BCNU) agents were examined in two colon cell lines (HCT15 and CO115). DNA damage was assessed by the comet assay with and without lesion-specific repair enzymes. Genotoxic agents were used for induction of DNA damage in both cell lines. Protective effects of extracts of three Salvia species, Salvia officinalis (SO), Salvia fruticosa (SF), and Salvia lavandulifolia (SL), against DNA damage induced by oxidative and alkylating agents were also determined. SO and SF protected against oxidative DNA damage in HCT15 cells. SO and SL decreased DNA damage induced by MNU in CO115 cells. In addition to chemopreventive effects of sage plant extracts, it was also important to know whether these plant extracts may interfere with alkylating agents such as BCNU used in cancer therapy, decreasing their efficacy. Our results showed that sage extracts tested and rosmarinic acid (RA), the main constituent, protected CO115 cells from DNA damage induced by BCNU. In HCT15 cells, only SF induced a reduction in BCNU-induced DNA damage. Sage water extracts and RA did not markedly change DNA repair protein expression in either cell line. Data showed that sage tea protected colon cells against oxidative and alkylating DNA damage and may also interfere with efficacy of alkylating agents used in cancer therapy.

[The role of melatonin in progress of pathology of a retina in patients of senior age group]

Epiphysis cerebri and its hormone melatonin play a leading role in aging. Melatonin affects many biochemical processes in a human body. The authors assume that there is a correlation between the level of melatonin and development of macular degeneration by age.

A dominant negative zebrafish Ahr2 partially protects developing zebrafish from dioxin toxicity

The toxicity by 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) is thought to be caused by activation of the aryl hydrocarbon receptor (AHR). However, our understanding of how AHR activation by TCDD leads to toxic effects is poor. Ideally we would like to manipulate AHR activity in specific tissues and at specific times. One route to this is expressing dominant negative AHRs (dnAHRs). This work describes the construction and characterization of dominant negative forms of the zebrafish Ahr2 in which the C-terminal transactivation domain was either removed, or replaced with the inhibitory domain from the Drosophila engrailed repressor protein. One of these dnAhr2s was selected for expression from the ubiquitously active e2fα promoter in transgenic zebrafish. We found that these transgenic zebrafish expressing dnAhr2 had reduced TCDD induction of the Ahr2 target gene cyp1a, as measured by 7-ethoxyresorufin-O-deethylase activity. Furthermore, the cardiotoxicity produced by TCDD, pericardial edema, heart malformation, and reduced blood flow, were all mitigated in the zebrafish expressing the dnAhr2. These results provide in vivo proof-of-principle results demonstrating the effectiveness of dnAHRs in manipulating AHR activity in vivo, and demonstrating that this approach can be a means for blocking TCDD toxicity.

Hepatoprotective action of Radix Paeoniae Rubra aqueous extract against CCl4-induced hepatic damage

In the present study the capacity of Radix Paeoniae Rubra aqueous extract (RPRAE) as an antioxidant to protect against carbon tetrachloride (CCl₄)-induced oxidative stress and hepatotoxicity in Wistar rats was investigated. Six groups of rats were used. Radix Paeoniae Rubra aqueous extract (100 or 200 or 300 mg/kg of bw) or bifendate (100 mg/kg of bw) were given daily by gavage to the animals on 28 consecutive days to elucidate the protective effects against CCl₄-induced hepatotoxicity. The 20% CCl₄/olive oil was gavage of gastric tube twice a week (on the third and seventh days of each week). The animals of normal control group were given only vehicle. The animals of CCl₄-treated group were administered with CCl₄ twice a week (on the third and seventh days of each week) and with vehicle on rest of the days. The test materials were found effective as hepatoprotective agents, as evidenced by plasma and liver biochemical parameters. Therefore, the results of this study show that Radix Paeoniae Rubra aqueous extract can protect the liver against CCl₄-induced oxidative damage in rats, and the hepatoprotective effects might be correlated with its antioxidant and free radical scavenger effects.

[Dependence of protective effect of alpha-tocopherol on its concentration and time of action on PC12 cell under conditions of oxidative stress]

At the short-term incubation (0.5 and 1.5 h) of cells of the PC12 neuronal line with alpha-tocopherol, its protective effect against the cytotoxic hydrogen peroxide action was increased with rise of its concentration in samples; the protection was practically absent at action of nanomolar antioxidant concentrations, but was well expressed at its micromolar concentrations. These data agree with the concept that alpha-tocopherol increases the cell living activity by reacting directly with free radicals, which leads to formation of the less reactive compounds deprived of non-paired electron. The evidence is obtained that at the long-term action on PC12 cells, alpha-tocopherol not only in micro-, but also in nanomolar concentrations increases statistically significantly the cell living activity under conditions of oxidative stress. As follows from the obtained data, an important role in realization of the alpha-tocopherol protective effect at the long-term incubation with it seems to be played by modulation by this antioxidant of activity of protein kinase activated by extracellular signaling, phosphatidylinosite 3-kinase, and protein kinase C.

Influence of dihydropyridine calcium antagonist nitrendipine on benzo(a)pyrene-induced oxidative stress

The aim of this study was to investigate the influence of nitrendipine (NIT), a dihydropyridine derived calcium channel antagonist, on polycyclic aromatic hydrocarbon benzo(a)pyrene (BAP)-induced oxidative stress. Male Sprague Dawley rats (155-220 g) were divided into four groups: Control (corn oil, i.p.); BAP (200 mg/kg, i.p.), BAP + NIT (200 mg/kg, i.p. + 50 mg/kg, i.p.), and NIT (50 mg/kg, i.p.) groups. Twenty-four hours after the injection of BAP, the rats were sacrificed and blood samples, liver, lung, and brain tissues were removed to determine serum alanine transaminase (ALT), aspartate transferase (AST), and gamma-glutamyltransferase (GGT) activities and tissue thiobarbituric acid reactive substances (TBARS), glutathione (GSH), and superoxide dismutase (SOD) levels. BAP significantly elevated serum ALT and TBARS levels in all tissues. However, NIT pre-treatment protected against increasing TBARS levels in lung and brain tissues. In addition, NIT pre-treatment significantly increased SOD levels in lung and liver tissues, as well as GSH levels in the lungs, compared to the BAP group. Thus, in conclusion, further studies are required to confirm the protective effects of calcium channel blockers, especially in liver tissue.

Ghrelin inhibits hydrogen peroxide-induced apoptotic cell death of oligodendrocytes via ERK and p38MAPK signaling

Here, we examined the protective effect of ghrelin on apoptotic cell death induced by hydrogen peroxide (H₂O₂) in primary oligodendrocyte cultures. Ghrelin receptor, growth hormone secretagogue receptor 1a, was expressed in mature oligodendrocytes. H₂O₂ (1 mm) treatment induced apoptotic cell death of oligodendrocytes, which was significantly inhibited by ghrelin treatment. Ghrelin also reduced cytochrome c release, and caspase-3 activation increased by H₂O₂ treatment. Furthermore, the protective effect of ghrelin against H₂O₂-induced oligodendrocyte cell death was mediated through growth hormone secretagogue receptor 1a. Both ERK and p38MAPK were activated (peaked at 8 h in ERK and 1 h in p38MAPK) by H₂O₂ treatment, whereas c-Jun N-terminal kinase and Akt were not. Interestingly, ghrelin further increased ERK activation and decreased p38MAPK activation after H₂O₂ treatment. Next, we tried to elucidate the role of ERK and p38MAPK activation in H₂O₂-induced apoptotic cell death of oligodendrocytes using pharmacological inhibitors. We found that the inhibition of apoptotic cell death of oligodendrocytes by ghrelin was abolished by ERK inhibitor, PD98059 (20 μM), whereas cell survival was increased by p38MAPK inhibitor, SB203580 (10 μM). These results thus indicate that ghrelin inhibits H₂O₂ -induced oligodendrocytes cell death in part by increasing ERK activation and decreasing p38MAPK activation, and ghrelin may represent a potential therapeutic agent for protecting oligodendrocytes in central nervous system injuries.

A protective role for complement C3 protein during pandemic 2009 H1N1 and H5N1 influenza A virus infection

Highly pathogenic H5N1 influenza infections are associated with enhanced inflammatory and cytokine responses, severe lung damage, and an overall dysregulation of innate immunity. C3, a member of the complement system of serum proteins, is a major component of the innate immune and inflammatory responses. However, the role of this protein in the pathogenesis of H5N1 infection is unknown. Here we demonstrate that H5N1 influenza virus infected mice had increased levels of C5a and C3 activation byproducts as compared to mice infected with either seasonal or pandemic 2009 H1N1 influenza viruses. We hypothesized that the increased complement was associated with the enhanced disease associated with the H5N1 infection. However, studies in knockout mice demonstrated that C3 was required for protection from influenza infection, proper viral clearance, and associated with changes in cellular infiltration. These studies suggest that although the levels of complement activation may differ depending on the influenza virus subtype, complement is an important host defense mechanism.

Diabetic nephropathy and multiorgan protection. Part II

Diabetic nephropathy (DN) presents a complex pathogenesis in which both the vascular system and the metabolism, in its complexity and mainly glucidic metabolism, are involved. Together with the glucid metabolism, lipid metabolism, anemia, oxidative stress, generalised inflammation, vitamin D disorders and smoking participate in DN pathogenesis. All these factors that disturb the homeostasis of the patient with DN require protective factors which will be presented in the second part of the paper. Like hypotensive medication, and especially the inhibitors of the renin angiotensin aldosterone (RAAS) system, antiproteinuric medication, and especially intensive control of glycaemia that have an important protective role, the pathogenic factors mentioned above also require protective measures. As they interest the whole organism in DN and in DM, respectively, we speak about multiple organ protection or multiorgan protection. The concept of multiorgan protection is especially important in DM. Although sometimes, some measures with multiorgan protective character are applied in current practice, it is necessary that they should be gathered and applied within a well established framework, a fact that is achieved by the concept of multiorganprotection. Diabetes mellitus, requires multiple measures of protection because of its vascular and metabolic complications. Diabetic nephropathy represents an important complication of diabetes mellitus, frequently associated with its other complications. The first part of the paper presented the concept of multiorgan protection, as well as some of the main protective measures: control of blood pressure mainly by means of inhibitors of the renine angiotensine aldosterone system, glycaemia monitoring and antiproteinuric treatment. The second part of the paper refers to protective measures used in diabetes mellitus, and diabetic nephropathy, respectively, regarding control of the anaemia, of endothelial disturbances, of the metabolism of lipids, of oxidative stress, of inflammation, smoking, of the metabolism of vitamin D, respectively. Diabetic nephropathy, by the complexity of its lesions, as well as by the complications of diabetes mellitus, cannot be regarded as separate from the organism seen as a unitary whole, a reason because of which the measures of protection are not limited only to the kidney, they must address all organs and metabolism in general, requiring measures of multiorgan protection.

Metallothionein gene expression in liver of rats exposed to cadmium and supplemented with zinc and selenium

Cadmium (Cd), one of the most widely distributed heavy metals, is highly toxic to humans and animals. It is well known that zinc (Zn) and selenium (Se) administration reduce the Cd-induced toxicity and that metallothioneins can have a protective effect to mitigate Cd toxicity in biological systems. In this study we report the expression analysis of the two metallothioneines gene classes MT-1 and MT-2 as well as the total metalloprotein content in the liver of rats exposed to Cd (200 ppm), Cd + Zn (200 ppm + 500 ppm), Cd + Se (200 ppm + 0.1 ppm) or Cd + Zn + Se (200 ppm + 500 ppm + 0.1 ppm) in their drinking water for 35 days. Metals accumulation was quantified in rat liver. Cd decreased significantly the hepatic concentrations of Se and increased those of Zn. The treatment of Cd-exposed rats with Se alone or combined with Zn reversed the Cd-induced depletion of Se concentrations in the liver. However, Zn or Zn + Se administration significantly increased the liver Cd uptake and had no effect on the Cd-induced increase in hepatic concentrations of Zn. The molecular assay showed a decreasing trend of MT-1 relative gene expression levels in animals supplemented with Zn (6.87-fold), Se (3.58-fold), and their combination (1.69-fold) when compared to Cd-treated animals (16.22-fold). Upregulation of the MT-2 expression were recorded in all conditions, although fold induction levels were less pronounced than MT-1 expressions. Our data suggest that the well-established protective effect of Zn and Se against Cd-induced toxicity passes through non-MT gene expression mechanisms, being more dependent on the oxidative stress status of the cell.

1,5-anhydro-D-fructose and its derivatives: biosynthesis, preparation and potential medical applications

1,5-Anhydro-D-fructose (AF) was first found in fungi and red algae. It is produced by the degradation of glycogen, starch and maltosaccharides with α-1,4-glucan lyase (EC 4.2.2.13). In vivo, AF is metabolized to 1,5-anhydro-D-glucitol (AG), ascopyrone P (APP), microthecin and other derivatives via the anhydrofructose pathway. The genes coding for the enzymes in this pathway have been cloned, enabling the large-scale production of AF and related products in a cell-free reactor. The possible applications of these products in medicine have been evaluated using both in vitro and in vivo systems. Thus AF is a useful anticariogenic agent as it inhibits the growth of the oral pathogen Streptococcus mutans, impairing the production of plaque-forming polysaccharides and lactic acid. AF also shows anti-inflammatory and anticancer effects. AG is used as a diabetic marker for glycemic control. AG also stimulates insulin secretion in insulinoma cell lines. in vivo, APP has been shown to lengthen the life span of cancer-afflicted mice. It interferes with tumor growth and metastasis by its cidal effects on fast multiplying cells. Microthecin inhibits the growth of the human pathogen Pseudomonas aeruginosa PAO1, particularly under anaerobic conditions. The pharmaceutical usefulness of the other AF metabolites 1,5-anhydro-D-mannitol,1-deoxymannojirimycin, haliclonol, 5-epipentenomycin I, bissetone, palythazine, isopalythazine, and clavulazine remains to be investigated. In this review AF and its metabolites as the bioactive natural products for their pharmaceutical potentials are discussed.

Reduced expression of IFIH1 is protective for type 1 diabetes

IFIH1 (interferon induced with helicase C domain 1), also known as MDA5 (melanoma differentiation-associated protein 5), is one of a family of intracellular proteins known to recognise viral RNA and mediate the innate immune response. IFIH1 is causal in type 1 diabetes based on the protective associations of four rare variants, where the derived alleles are predicted to reduce gene expression or function. Originally, however, T1D protection was mapped to the common IFIH1 nsSNP, rs1990760 or Thr946Ala. This common amino acid substitution does not cause a loss of function and evidence suggests the protective allele, Ala(946), may mark a haplotype with reduced expression of IFIH1 in line with the protection conferred by the four rare loss of function alleles. We have performed allele specific expression analysis that supports this hypothesis: the T1D protective haplotype correlates with reduced IFIH1 transcription in interferon-β stimulated peripheral blood mononuclear cells (overall p = 0.012). In addition, we have used multiflow cytometry analysis and quantitative PCR assays to prove reduced expression of IFIH1 in individuals heterozygous for three of the T1D-associated rare alleles: a premature stop codon, rs35744605 (Glu627X) and predicted splice variants, rs35337543 (IVS8+1) and rs35732034 (IVS14+1). We also show that the nsSNP, Ile923V, does not alter pre-mRNA levels of IFIH1. These results confirm and extend the new autoimmune disease pathway of reduced IFIH1 expression and protein function protecting from T1D.