The impact of chronic Trimethylamine N-oxide administration on liver oxidative stress, inflammation, and fibrosis

TMAO, a gut microbiota derived byproduct, has been associated with various cardiometabolic diseases by promoting oxidative stress and inflammation. The liver is the main organ for TMAO production and chronic exposure to high doses of TMAO could alter its function. In this study, we evaluated the effect of chronic exposure of high TMAO doses on liver oxidative stress, inflammation, and fibrosis. TMAO was administered daily via gastric gavage to laboratory rats for 3 months. Blood was drawn for the quantification of TMAO, and liver tissues were harvested for the assessment of oxidative stress (MDA, GSH, GSSG, GPx, CAT, and 8-oxo-dG) and inflammation by quantification of IL-1α, TNF-α, IL-10, TGF-β, NOS and COX-2 expression. The evaluation of fibrosis was made by Western blot analysis of α-SMA and Collagen-3 protein expression. Histological investigation and immunohistochemical staining of iNOS were performed in order to assess the liver damage. After 3 months of TMAO exposure, TMAO serum levels enhanced in parallel with increases in MDA and GSSG levels in liver tissue and lower values of GSH and GSH/GSSG ratio as well as a decrease in GPx and CAT activities. Inflammation was also highlighted, with enhanced iNOS, COX-2, and IL-10 expression, without structural changes and without induction of liver fibrosis.

Lactobacillus rhamnosus probiotic treatment modulates gut and liver inflammatory pathways in a hepatocellular carcinoma murine model. A preliminary study

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is a growing global concern with an increasing incidence rate. The intestinal microbiota has been identified as a potential culprit in modulating the effects of antitumoral drugs. We aimed to assess the impact of adding Lactobacillus rhamnosus probiotic to regorafenib in mice with HCC.

METHODS

Cirrhosis and HCCs were induced in 56 male Swiss mice via diethylnitrosamine injection and carbon tetrachloride administration. Mice were divided into four groups: treated with vehicle (VC), regorafenib (Rego), L. rhamnosus probiotic, and a combination of regorafenib and probiotic (Rego-Pro). After 3 weeks of treatment, liver and intestinal fragments were collected for analysis.

RESULTS

Regorafenib elevated gut permeability, an effect mitigated by probiotic intervention, which exhibited a notable correlation with reduced inflammation (p < 0.01). iNOS levels were also reduced by adding the probiotic with respect to the mice treated with regorafenib only (p < 0.001). Notably, regorafenib substantially increased IL-6, TNF-a and TLR4 in intestinal fragments (p < 0.01). The administration of the probiotic effectively restored IL-6 to its initial levels (p < 0.001).

CONCLUSION

Reducing systemic and intestinal inflammation by administering L. rhamnosus probiotic may alleviate tumoral resistance and systemic adverse effects.

Hybrid Material Based on Vaccinium myrtillus L. Extract and Gold Nanoparticles Reduces Oxidative Stress and Inflammation in Hepatic Stellate Cells Exposed to TGF-β

(1) Background: The study aimed to investigate the impact of gold nanoparticles capped with Cornus sanguinea (NPCS) and mixed with a fruit extract (Vaccinum myrtillus L.-VL) on human hepatic stellate cells (LX-2) exposed to TGF-β. (2) Methods: NPCS were characterized by UV-Vis, transmission electron microscopy (TEM), zeta potential measurement, X-ray diffraction (XRD) and energy dispersive spectroscopy (EDX). The cytotoxic effects of VL, NPCS and of the hybrid compounds obtained by mixing the two components in variable proportions (NPCS-VL) were assessed. LDH activity, MDA levels, secretion of inflammation markers, the expression of fibrogenesis markers and collagen I synthesis were estimated after treating the cells with a mixture of 25:25 μg/mL NPCS and VL. (3) Results: TEM analysis showed that NPCS had spherical morphology and homogenous distribution, while their formation and elemental composition were confirmed by XRD and EDX analysis. TGF-β increased cell membrane damage as well as secretion of IL-1β, IL-1α and TLR4. It also amplified the expression of α-SMA and type III collagen and induced collagen I deposition. NPCS administration reduced the inflammation caused by TGF-β and downregulated α-SMA expression. VL diminished LDH activity and the secretion of proinflammatory cytokines. The NPCS-VL mixture maintained IL-1β, IL-1α, TLR4 and LDH at low levels after TGF-β exposure, but it enhanced collagen III expression. (4) Conclusions: The mixture of NPCS and VL improved cell membrane damage and inflammation triggered by TGF-β and mitigated collagen I deposition, but it increased the expression of collagen III, suggestive of a fibrogenetic effect of the hybrid material.

Goji-Berry-Mediated Green Synthesis of Gold Nanoparticles and Their Promising Effect on Reducing Oxidative Stress and Inflammation in Experimental Hyperglycemia

The present report focuses on a rapid and convenient method applicable in the green synthesis of gold nanoparticles (AuNPs) using goji berry (Lycium barbarum-LB) extracts rich in antioxidant compounds, as well as on the structural analysis and evaluation of the induced antioxidant protection and anti-inflammatory effects of the synthesized gold nanoparticles upon endothelial cells (HUVECs) exposed to hyperglycemia. The synthesized AuNPs were characterized using ultraviolet-visible (UV-Vis) spectroscopy and transmission electron microscopy (TEM), whereas the presence of bioactive compounds from the L. barbarum fruit extract on the surface of the nanoparticles was confirmed using Fourier transform infrared spectroscopy (FTIR). The antioxidant activity of the biosynthesized gold nanoparticles was evaluated on the HUVEC cell line. The results reveal that AuNPs with a predominantly spherical shape and an average size of 30 nm were obtained. The UV-Vis spectrum showed a characteristic absorption band at λmax = 536 nm of AuNPs. FTIR analysis revealed the presence of phenolic acids, flavonoids and carotenoids acting as capping and stabilizing agents of AuNPs. Both the L. barbarum extract and AuNPs were well tolerated by HUVECs, increased the antioxidant defense and decreased the production of inflammatory cytokines induced via hyperglycemia-mediated oxidative damage.

Sweeteners' Influence on In Vitro α-Glucosidase Inhibitory Activity, Cytotoxicity, Stability and In Vivo Bioavailability of the Anthocyanins from Lingonberry Jams

Several lines of evidence demonstrate the multiple health-promoting properties of anthocyanins, but little is known regarding the bioavailability of these phytochemicals. Therefore, the stability during storage and bioavailability of anthocyanins from lingonberries jams were determined by HPLC, together with the impact of used sweeteners on their adsorption. Further, the in vitro α-glucosidase inhibition using spectrophotometric methods and cytotoxicity determined on normal and colon cancer cells were communicated. The content of anthocyanins was significantly decreased during storage in coconut sugar-based jam, but was best preserved in jam with fructose and stevia. Fructose and stevia-based jams showed the highest inhibition activity upon α-glucosidase. Lingonberry jams showed no cytotoxic effects on normal cells, but at low concentration reduced the tumor cells viability. Anthocyanins were still detectable in rats' blood streams after 24 h, showing a prolonged bioavailability in rats. This study brings important results that will enable the development of functional food products.

The Acute Effect of Trimethylamine-N-Oxide on Vascular Function, Oxidative Stress, and Inflammation in Rat Aortic Rings

A growing body of evidence suggests that the gut microbiota affects the cardiovascular system directly and indirectly via biologically active molecules. TMAO, a key metabolite produced by gut bacteria is implicated in atherosclerosis and chronic endothelial dysfunction, but with an unclear effect on vascular tone, oxidative stress, and inflammation. Our study aimed to evaluate the acute effects of TMAO on vascular contractility in relation with oxidative stress markers and inflammation. Aortic rings were harvested from laboratory rats and placed in a tissue bath system containing TMAO in concentrations of 300, 100, 10 µM, and control. Vascular tone under the influence of vasoconstrictor phenylephrine and non-endothelial-dependent vasodilator sodium nitroprusside was assessed using force transducers connected to a computer-based acquisition system. Oxidative stress and inflammation were quantified by vascular assessment of the activity of NF-κB, NRF2, SOD1, and iNOS by western-blotting and MDA by spectrofluorimetry. After the incubation of the aortic rings in TMAO solutions for 1 h, there was no difference in vasoconstrictor and non-endothelial vasodilator response between the studied doses. TMAO acutely induced oxidative stress and inflammation, significantly increasing levels of MDA and the expression of NF-κB, NRF2, SOD1, and iNOS, mostly in a dose-dependent manner. Our study showed the lack of a short-term effect of studied TMAO doses on vascular contractility, but demonstrated an acute prooxidative effect and activation of major inflammatory pathways, which can partially explain the detrimental effects of TMAO in cardiovascular disease.

Green Synthesized Gold and Silver Nanoparticles Increased Oxidative Stress and Induced Cell Death in Colorectal Adenocarcinoma Cells

The research investigated the effect of gold (Au-CM) and silver nanoparticles (Ag-CM) phytoreduced with Cornus mas fruit extract (CM) on a human colorectal adenocarcinoma (DLD-1) cell line. The impact of nanoparticles on the viability of DLD-1 tumor cells and normal cells was evaluated. Oxidative stress and cell death mechanisms (annexin/propidium iodide analysis, caspase-3 and caspase-8 levels, p53, BCL-2, BAX, NFkB expressions) as well as proliferation markers (Ki-67, PCNA and MAPK) were evaluated in tumor cells. The nanoparticles were characterized using UV-Vis spectroscopy and transmission electron microscopy (TEM) and by measuring zeta potential, hydrodynamic diameter and polydispersity index (PDI). Energy dispersive X-ray (EDX) and X-ray powder diffraction (XRD) analyses were also performed. The nanoparticles induced apoptosis and necrosis of DLD-1 cells and reduced cell proliferation, especially Ag-CM, while on normal cells, both nanoparticles maintained their viability up to 80%. Ag-CM and Au-CM increased the expressions of p53 and NFkB in parallel with the downregulation of BCL-2 protein and induced the activation of caspase-8, suggesting the involvement of apoptosis in cell death. Lipid peroxidation triggered by Ag-CM was correlated with tumor cell necrosis rate. Both nanoparticles obtained with phytocompounds from the CM extract protected normal cells and induced the death of DLD-1 tumor cells, especially by apoptosis.

Magnetic Nanoclusters Stabilized with Poly[3,4-Dihydroxybenzhydrazide] as Efficient Therapeutic Agents for Cancer Cells Destruction

Magnetic structures exhibiting large magnetic moments are sought after in theranostic approaches that combine magnetic hyperthermia treatment (MH) and diagnostic magnetic resonance imaging in oncology, since they offer an enhanced magnetic response to an external magnetic field. We report on the synthesized production of a core-shell magnetic structure using two types of magnetite nanoclusters (MNC) based on a magnetite core and polymer shell. This was achieved through an in situ solvothermal process, using, for the first time, 3,4-dihydroxybenzhydrazide (DHBH) and poly[3,4-dihydroxybenzhydrazide] (PDHBH) as stabilizers. Transmission electron microscopy (TEM) analysis showed the formation of spherical MNC, X-ray photoelectronic spectroscopy (XPS) and Fourier transformed infrared (FT-IR) analysis proved the existence of the polymer shell. Magnetization measurement showed saturation magnetization values of 50 emu/g for PDHBH@MNC and 60 emu/g for DHBH@MNC with very low coercive field and remanence, indicating that the MNC are in a superparamagnetic state at room temperature and are thus suitable for biomedical applications. MNCs were investigated in vitro, on human normal (dermal fibroblasts-BJ) and tumor (colon adenocarcinoma-CACO2, and melanoma-A375) cell lines, in view of toxicity, antitumor effectiveness and selectivity upon magnetic hyperthermia. MNCs exhibited good biocompatibility and were internalized by all cell lines (TEM), with minimal ultrastructural changes. By means of flowcytometry apoptosis detection, fluorimetry, spectrophotometry for mitochondrial membrane potential, oxidative stress, ELISA-caspases, and Western blot-p53 pathway, we show that MH efficiently induced apoptosis mostly via the membrane pathway and to a lower extent by the mitochondrial pathway, the latter mainly observed in melanoma. Contrarily, the apoptosis rate was above the toxicity limit in fibroblasts. Due to its coating, PDHBH@MNC showed selective antitumor efficacy and can be further used in theranostics since the PDHBH polymer provides multiple reaction sites for the attachment of therapeutic molecules.

Iron chelation alleviates multiple pathophysiological pathways in a rat model of cardiac pressure overload

Iron dysmetabolism affects a great proportion of heart failure patients, while chronic hypertension is one of the most common risk factors for heart failure and death in industrialized countries. Serum data from reduced ejection fraction heart failure patients show a relative or absolute iron deficiency, whereas cellular myocardial analyses field equivocal data. An observed increase in organellar iron deposits was incriminated to cause reactive oxygen species formation, lipid peroxidation, and cell death. Therefore, we studied the effects of iron chelation on a rat model of cardiac hypertrophy. Suprarenal abdominal aortic constriction was achieved surgically, with a period of nine weeks to accommodate the development of chronic pressure overload. Next, deferiprone (100 mg/kg/day), a lipid-permeable iron chelator, was administered for two weeks. Pressure overload resulted in increased inflammation, fibrotic remodeling, lipid peroxidation, left ventricular hypertrophy and mitochondrial iron derangements. Deferiprone reduced cardiac inflammation, lipid peroxidation, mitochondrial iron levels, and hypertrophy, without affecting circulating iron levels or ejection fraction. In conclusion, metallic molecules may pose ambivalent effects within the cardiovascular system, with beneficial effects of iron redistribution, chiefly in the mitochondria.

Doxorubicin-induced acute cardiotoxicity is associated with increased oxidative stress, autophagy, and inflammation in a murine model

Drug-induced cardiotoxicity is a life-threatening side effect of doxorubicin (DOX) treatment that impacts patient prognosis and survival. In the majority of cases, the acute clinical form often remains asymptomatic, with few patients presenting rather nonspecific electrocardiographic abnormalities. While chronic toxicity has been more widely studied, the alterations appearing in acute cardiotoxicity are much less investigated. Thus, our in vivo study aimed to evaluate the process of DOX-induced acute myocardial toxicity by investigating oxidative stress and autophagy markers as mechanisms of myocardial toxicity in correlation with echocardiography and electrocardiography findings. Our results show that both autophagy and oxidative homeostasis were disrupted as soon as 7 days after DOX treatment, alterations that occurred even before the significant increase of NT-proBNP, a clinical marker for cardiac suffering. Moreover, we found a large number of alterations in the electrocardiography and echocardiography of treated rats. These findings suggest that DOX-induced myocardial toxicity started early after treatment initiation, possibly marking the initial phase of the unfolding process of cardiac damage. Further studies are required to completely decipher the mechanisms of DOX-induced cardiotoxicity.

Characterization and In Vitro Biocompatibility of Two New Bioglasses for Application in Dental Medicine-A Preliminary Study

Bioactive glasses (BGs), also known as bioglasses, are very attractive and versatile materials that are increasingly being used in dentistry. For this study, two new bioglasses-one with boron (BG1) and another with boron and vanadium (BG2)-were synthesized, characterized, and tested on human dysplastic keratinocytes. The in vitro biological properties were evaluated through pH and zeta potential measurement, weight loss, Ca²⁺ ions released after immersion in phosphate-buffered saline (PBS), and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) analysis. Furthermore, biocompatibility was evaluated through quantification of lactate dehydrogenase activity, oxidative stress, transcription factors, and DNA lesions. The results indicate that both BGs presented the same behavior in simulated fluids, characterized by high degradation, fast release of calcium and boron in the environment (especially from BG1), and increased pH and zeta potential. Both BGs reacted with the fluid, particularly BG2, with irregular deposits covering the glass surface. In vitro studies demonstrated that normal doses of the BGs were not cytotoxic to DOK, while high doses reduced cell viability. Both BGs induced oxidative stress and cell membrane damage and enhanced NFkB activation, especially BG1. The BGs down-regulated the expression of NFkB and diminished the DNA damage, suggesting the protective effects of the BGs on cell death and efficacy of DNA repair mechanisms.

Comparative Study of the Pharmacological Properties and Biological Effects of Polygonum aviculare L. herba Extract-Entrapped Liposomes versus Quercetin-Entrapped Liposomes on Doxorubicin-Induced Toxicity on HUVECs

This study aimed to evaluate the comparative biological effects of Polygonum aviculare L. herba (PAH) extract and quercetin-entrapped liposomes on doxorubicin (Doxo)-induced toxicity in HUVECs. HUVECs were treated with two formulations of liposomes loaded with PAH extract (L5 and L6) and two formulations of liposomes loaded with quercetin (L3 prepared with phosphatidylcholine and L4 prepared with phosphatidylserine). The results obtained with atomic force microscopy, zeta potential and entrapment liposome efficiency confirmed the interactions of the liposomes with PAH or free quercetin and a controlled release of flavonoids entrapped in all the liposomes. Doxo decreased the cell viability and induced oxidative stress, inflammation, DNA lesions and apoptosis in parallel with the activation of Nrf2 and NF-kB. Free quercetin, L3 and L4 inhibited the oxidative stress and inflammation and reduced apoptosis, particularly L3. Additionally, these compounds diminished the Nrf2 and NF-kB expressions and DNA lesions, principally L4. PAH extract, L5 and L6 exerted antioxidant and anti-inflammatory activities, reduced γH2AX formation and inhibited extrinsic apoptosis and transcription factors activation but to a lesser extent. The loading of quercetin in liposomes increased the cell viability and exerted better endothelial protection compared to free quercetin, especially L3. The liposomes with PAH extract had moderate efficiency, mainly due to the antioxidant and anti-inflammatory effects and the inhibition of extrinsic apoptosis.

Escitalopram Targets Oxidative Stress, Caspase-3, BDNF and MeCP2 in the Hippocampus and Frontal Cortex of a Rat Model of Depression Induced by Chronic Unpredictable Mild Stress

In recent years, escitalopram (ESC) has been suggested to have different mechanisms of action beyond its well known selective serotonin reuptake inhibition. The aim of this study is to investigate the effects of escitalopram on oxidative stress, apoptosis, brain-derived neurotrophic factor (BDNF), Methyl-CpG-binding protein 2 (MeCP2), and oligodendrocytes number in the brain of chronic unpredictable mild stress-induced depressed rats. The animals were randomised in four groups (8 in each group): control, stress, stress + ESC 5 and stress + ESC 5/10. ESC was administered for 42 days in a fixed dose (5 mg/kg b.w.) or in an up-titration regimen (21 days ESC 5 mg/kg b.w. then 21 days ESC 10 mg/kg b.w.). Sucrose preference test (SPT) and elevated plus maze (EPM) were also performed. ESC improved the percentage of sucrose preference, locomotion and anxiety. ESC5/10 reduced the oxidative damage in the hippocampus and improved the antioxidant defence in the hippocampus and frontal lobe. ESC5/10 lowered caspase 3 activity in the hippocampus. Escitalopram had a modulatory effect on BDNF and the number of oligodendrocytes in the hippocampus and frontal lobe and also improved the MeCP2 expressions. The results confirm the multiple pathways implicated in the pathogenesis of depression and suggest that escitalopram exerts an antidepressant effect via different intricate mechanisms.

The impact of Sambucus nigra L. extract on inflammation, oxidative stress and tissue remodeling in a rat model of lipopolysaccharide-induced subacute rhinosinusitis

Rhinosinusitis is a common disorder related to inflammation of paranasal sinuses and nasal cavity mucosa. Herbal medicines could be an option in the treatment of rhinosinusitis due to their anti-inflammatory and anti-oxidative properties. The study aims to investigate the effect of intranasal Sambucus nigra L. subsp. nigra (SN) extract against inflammation, oxidative stress, and tissue remodeling in nasal and sinus mucosa, but also in serum, lungs, and brain, in Wistar rat model of subacute sinonasal inflammation induced by local administration of lipopolysaccharides (LPS), from Escherichia Coli. The cytokines (TNF-α, IL-1β, IL-6) and oxidative stress (malondialdehyde) in nasal mucosa, blood, lungs, and brain were analyzed. In addition, a histopathological examination was performed, and NF-kB, MMP2, MMP9, TIMP1 expressions were also evaluated in nasal mucosa. Both doses of LPS increased the production of cytokines in all the investigated tissues, especially in the nasal mucosa and blood (p < 0.01 and p < 0.05), and stimulated their secretion in the lungs, and partially in the brain. Malondialdehyde increased in all the investigated tissues (p < 0.01 and p < 0.05). In parallel, upregulation of NF-kB and MMP2 expressions with downregulation of TIMP1, particularly at high dose of LPS, was observed. SN extract reduced the local inflammatory response, maintained low levels of IL-6, TNF-α, and IL-1β. In lungs, SN reduced all cytokines levels while in the brain, the protective effect was noticed only on IL-6. Additionally, SN diminished lipid peroxidation and downregulated NF-kB in animals exposed to a low dose of LPS, with increased TIMP1 expression, while in animals treated with a high dose of LPS, SN increased NF-kB, MMP2, and MMP9 levels. In conclusion, SN extract diminished the inflammatory response, reduced generation of reactive oxygen species (ROS) and, influenced MMPs expressions, suggesting the benficial effect of SN extract on tissue remodeling in subacute rhinosinusitis and on systemic inflammatory response.

The impact of silver nanoparticles phytosynthesized with Viburnum opulus L. extract on the ultrastrastructure and cell death in the testis of offspring rats

AIM

To investigate the effects of prenatal exposure to AgNPs obtained by green synthesis with Viburnum opulus L. extract on the testis in male offspring rats.

MATERIAL AND METHODS

Two different doses of AgNPs (0.8 and 1.5 mg/kg b.w.) and vehicle (PBS) were administered to Wistar female rats on days 3-14 of gestation. At 6 weeks after birth, the ultrastructural changes in correlation with the amount of silver as well as the parameters of oxidative stress, inflammation and cell death mechanisms in the testis of male offspring were evaluated.

RESULTS

AgNPs administered during pregnancy crossed the placental and testicular barriers and induced oxidative stress, DNA damage and autophagy as mechanism of cell toxicity. The markers of inflammation and apoptosis decreased after AgNPs exposure while the NFkB activation increased. TEM examination revealed important ultrastructural changes of Sertoli cells, numerous vacuoles and cytoplasmic changes suggestive of the cell's evolution towards necrosis.

CONCLUSION

Phytoreduced silver nanoparticles with polyphenols from Viburnum opulus L. fruit extract, administered during the embryological development of the male gonad, have testicular toxic effects in offspring even at 6 weeks after birth.

Biosynthesis of silver nanoparticles using Sambucus nigra L. fruit extract for targeting cell death in oral dysplastic cells

The study aims to evaluate the impact of silver nanoparticles, phytosynthesized with polyphenols from Sambucus nigra L. (SN) fruit extract (AgSN), on dysplastic oral keratinocytes (DOK) and human gingival fibroblasts (HGF) in terms of cell viability and apoptosis. The morphology and ultrastructure of treated cells as well as the mechanisms involved in cell death induction were investigated in DOK cultures. The structure of AgSN was studied by using the appropriate analysis tools such as UV-Vis, transmission electron microscopy, Raman spectroscopy, dynamic light scattering (DLS) and zeta potential assessment. DOK and HGF were treated either with silver nanoparticles capped with Sambucus nigra L. extract or with SN extract. Untreated cells were used as controls. Viability was determined by MTS assay. Transmission electronic microscopy (TEM) was used to evaluate the intracellular localization of the nanoparticles at 4 and 24 h. Annexin V-FITC/propidium iodide staining and the expressions of p53, BAX, BCL2, NFkB, phosphorylated NFkB (pNFkB), pan AKT, pan phosphoAKT, LC3B and ɣH₂AX were evaluated to quantify the cell death. ELISA measurements of TNF-α and TRAIL was used for the study of the inflammatory response. Oxidative stress damage induced by nanoparticles was assessed by the malondialdehyde (MDA) level. Silver nanoparticles stimulated HGF proliferation and significantly diminished DOK viability at doses higher than 20 μg/ml. TEM analysis demonstrated the internalization of silver nanoparticles and showed ultrastructural changes of cells such as the appearance of vacuoles, autophagosomes, endosomes. AgSN inhibited the pro-survival molecules and regulators of apoptosis, diminished oxidative stress and inflammation and induced cell death through various mechanisms: necrosis, autophagy and DNA lesions. SN extract had antioxidant and anti-inflammatory effect and increased the DNA lesions and autophagy in DOK cells. Silver nanoparticles protected the normal cells and induced cell death in dysplastic cells by different mechanisms thus offering beneficial effects in the treatment of oral dysplasia.

The impact of silver nanoparticles phytosynthesized with Viburnum opulus L. extract on the ultrastrastructure and cell death in the testis of offspring rats

AIM

To investigate the effects of prenatal exposure to AgNPs obtained by green synthesis with Viburnum opulus L. extract on the testis in male offspring rats.

MATERIAL AND METHODS

Two different doses of AgNPs (0.8 and 1.5 mg/kg b.w.) and vehicle (PBS) were administered to Wistar female rats on days 3-14 of gestation. At 6 weeks after birth, the ultrastructural changes in correlation with the amount of silver as well as the parameters of oxidative stress, inflammation and cell death mechanisms in the testis of male offspring were evaluated.

RESULTS

AgNPs administered during pregnancy crossed the placental and testicular barriers and induced oxidative stress, DNA damage and autophagy as mechanism of cell toxicity. The markers of inflammation and apoptosis decreased after AgNPs exposure while the NFkB activation increased. TEM examination revealed important ultrastructural changes of Sertoli cells, numerous vacuoles and cytoplasmic changes suggestive of the cell's evolution towards necrosis.

CONCLUSION

Phytoreduced silver nanoparticles with polyphenols from Viburnum opulus L. fruit extract, administered during the embryological development of the male gonad, have testicular toxic effects in offspring even at 6 weeks after birth.

Effects of silver and gold nanoparticles phytosynthesized with Cornus mas extract on oral dysplastic human cells

Background: Oral cancer is highly aggressive due to difficult diagnosis, therapy resistance and increasing frequency; thus finding prevention therapies is very important. Aim: This study evaluates the use of gold and silver nanoparticles (NPs), phyto-synthesized with Cornus mas extract against oral dysplastic lesions. Methods: NPs were characterized by UV-Vis, Fourier-transform infrared spectroscopy, transmission electron microscopy, x-ray diffraction and laser Doppler microelectrophoresis. Biological testing employed two human oral cell lines: gingival fibroblasts and dysplastic keratinocytes and evaluated viability, cell death mechanisms and cellular uptake. Results: NPs induced selective toxic effects against dysplastic cells. p53/BAX/BCL2 activation and PI3K/AKT inhibition led to cell death through necrosis and apoptosis. NPs also induced antioxidant and anti-inflammatory effects. Conclusion: NPs of gold and silver showed promising beneficial effects in the therapy of oral dysplasia.

Gold nanoparticles phytoreduced with Cornus mas extract mitigate some of gliadin effects on Caco-2 cells

Celiac disease (CD) is an autoimmune condition that occurs in genetically predisposed people where the ingestion of gluten produces damage in the small intestine. The treatment accepted until now is a strict gluten free diet. This implies the need for novel or adjuvant treatments, in addition to the standard of care. The present study aimed to assess the effect of gold nanoparticles phytosynthesized with Cornus mas extract (AuCM) compared to Cornus mas extract (CM) and luteolin (LT) on Caco-2 cells, exposed or not to gliadin. Ultraviolet-visible spectroscopy and transmission electron microscopy were used for the characterization of AuCM. Measured cellular outcomes included oxidative stress markers (malondialdehyde level, catalase and superoxide dismutase activities), inflammatory response and cellular signaling and transcription factors involved in apoptosis (NFκB, pNFκB, NOS2, TNF-α, TRAIL, Bax, Bcl-2, p53). The internalization of gold nanoparticles in cells was evidenced by transmission electron microscopy (TEM). The gliadin administration induced oxidative stress, improved the activity of antioxidants enzymes, increased NOS2 and NFκB expressions and reduced pNFκB/NFκB ratio. In addition, gliadin enhanced TRAIL and Bcl-2 levels and reduced p53 expression in Caco-2 cells. The pretreatment with AuCM, CM extract and LT diminished oxidative stress and reduced NOS2 activity. AuCM and CM treatment amplified the expression of p53 and pNFκB/NFκB ratio and diminished Bcl-2, NFκB and pNFκB, especially AuCM. The results obtained confirmed that AuCM mitigate some of gliadin effects on Caco-2 cells through modulation of oxidative stress and inflammation.

Hepatoprotective effects of silymarin coated gold nanoparticles in experimental cholestasis

The present study reports the green synthesis of hybrid organic-inorganic gold nanocomposites using silymarin as reducing and capping agent. The structure of the silymarin loaded gold nanoparticles was investigated by using the appropriate analysis tools such as UV-Vis and Fourier-transform infrared spectroscopy (FTIR), and Transmission electron microscopy (TEM) techniques. TEM micrographs demonstrated that the gold nanoparticles were spherical in shape, well distributed and their mean size was about 10 nm. The in vivo hepatoprotective and antifibrogenic properties after bile duct ligation in rats of the silymarin coated gold nanoparticles were assessed. The changes regarding the blood tests and the liver histopathology were compared to the standard administration of silymarin. Silymarin loaded gold nanoparticles improved liver function, reduced cholestasis and oxidative stress parameters, with the increase of antioxidant support, and reduced inflammation and fibrosis in the liver of rats with extrahepatic cholestasis.

Daily oral administration of chlorogenic acid prevents the experimental carrageenan-induced oxidative stress

Inflammation and oxidative stress are interrelated processes, during which many pathological processes lead to the reactive oxygen species (ROS) and the cytokines release. The aim of this experimental study was to analyse the effects of chlorogenic acid, in oral daily administration, against the oxidative stress and oedema development in experimental carrageenan-induced rat paw inflammation. The oxidative stress parameters were investigated after a paw inflammation was produced in rats that previoulsy received, for 14 days, either chlorogenic acid (100 mg/day or 150 mg/day) or indomethacin (1 mg/kg/day). The paw oedema was measured through plethysmometry made at 2, 6 and 24 hours after carrageenan injection. The oxidative stress was investigated through spectrophotometry. Blood samples, paw skin and kidneys were collected to investigate malondialdehyde (MDA), glutathione (GSH) and oxidized glutathione (GSSG). The protein expression of oxidative stress-related pathways was analysed in skin and kidneys through Western blot. The present study showed that indomethacin and both doses of chlorogenic acid, after 14 days of oral administration, exerted antioedematous effects during the inflammation development after carrageenan local injection. Compared to the group that received only carrageenan injection, significant decreases of the inflamed paw volume were shown in the treated groups (P < 0.001), in all inflammation phases. The lipid peroxidation was significantly decreased by both doses of chlorogenic acid in inflamed skin (P < 0.0001) and kidney (P < 0.0001). In serum, it was significantly inhibited by indomethacin (P < 0.01) and by 100 mg/day of chlorogenic acid (P < 0.05). The antioxidant protection, evaluated through the ratio GSH/GSSG, was significantly increased by chlorogenic acid in inflamed skin (P < 0.0001) and kidney (100 mg/day, P < 0.01; 150 mg/day, P < 0.0001). In serum, only indomethacin administration produced significant increases of the antioxidant protection (P < 0.05). Western blot analysis showed significant decreases of COX-2 in inflamed skin and kidney in the groups of rats that received indomethacin or 100 mg/day of chlorogenic acid. The effects of chlorogenic acid on NF-κB and pNF-κB were dose-dependent.

Modulatory effects of Cornus sanguinea L. mediated green synthesized silver nanoparticles on oxidative stress, COX-2/NOS2 and NFkB/pNFkB expressions in experimental inflammation in Wistar rats

The present study presents a green, cost efficient and easy synthesis method of silver nanoparticles (AgNPs) using an aqueous extract of Cornus sanguinea L. fruits (CS). The phytosynthesized silver nanoparticles were characterized using various analytical techniques such as UV-Vis absorption spectroscopy, which confirmed the formation of AgNPs and FTIR spectroscopy, in order to certify the role of the biomolecules present in the fruit extract as reducing and capping agents of the AgNPs. The UV-Vis absorption spectrum showed a broad band at 407 nm characteristic for colloidal silver. Transmission electron microscopy was conducted to investigate the shape and size of the silver nanoparticles, revealing a spherical shape with an average particle size of 18 nm. The antioxidant and anti-inflammatory activities of the fruit extract and green synthesized silver nanoparticles were assessed in vivo on experimental inflammation. The obtained results showed that CS and AgNPs reduced oxidative stress in parallel with increasing of antioxidant defense and diminished the COX-2 expressions. CS extract had a dual effect on NFkB activation depending on the time of testing while AgNPs increased NFkB phosphorylation at 48 h. These results suggested that both AgNPs and CS extract exhibited antioxidant and anti-inflammatory activities but with a different dynamics of action.

Photodynamic Therapy in Melanoma - Where do we Stand?

BACKGROUND

Malignant melanoma is one of the most aggressive malignant tumors, with unpredictable evolution. Despite numerous therapeutic options, like chemotherapy, BRAF inhibitors and immunotherapy, advanced melanoma prognosis remains severe. Photodynamic therapy (PDT) has been successfully used as the first line or palliative therapy for the treatment of lung, esophageal, bladder, non melanoma skin and head and neck cancers. However, classical PDT has shown some drawbacks that limit its clinical application in melanoma.

OBJECTIVE

The most important challenge is to overcome melanoma resistance, due to melanosomal trapping, presence of melanin, enhanced oxidative stress defense, defects in the apoptotic pathways, immune evasion, neoangiogenesis stimulation.

METHOD

In this review we considered: (1) main signaling molecular pathways deregulated in melanoma as potential targets for personalized therapy, including PDT, (2) results of the clinical studies regarding PDT of melanoma, especially advanced metastatic stage, (3) progresses made in the design of anti-melanoma photosensitizers (4) inhibition of tumor neoangiogenesis, as well as (5) advantages of the derived therapies like photothermal therapy, sonodynamic therapy.

RESULTS

PDT represents a promising alternative palliative treatment for advanced melanoma patients, mainly due to its minimal invasive character and low side effects. Efficient melanoma PDT requires: (1) improved, tumor targeted, NIR absorbing photosensitizers, capable of inducing high amounts of different ROS inside tumor and vasculature cells, possibly allowing a theranostic approach; (2) an efficient adjuvant immune therapy.

CONCLUSION

Combination of PDT with immune stimulation might be the key to overcome the melanoma resistance and to obtain better, sustainable clinical results.

Effects of silver nanoparticles functionalized with Cornus mas L. extract on architecture and apoptosis in rat testicle

Aim: To assess ultrastructural changes, alterations in matrix metalloproteinase activity and apoptosis induced by silver nanoparticles (AgNPs) in the rat testicle. Materials & methods: For 45 days, two groups of animals received different doses of AgNPs (0.8 and 1.5 mg/kg b.w.), and a control group was given the buffer used as vehicle for AgNPs. At 7 and 15 days post-treatment, transmission electron microscopy, TUNEL assay, evaluation of NFkB, pNFkB, p53, Bcl-2 and Nrf2 expressions were performed on the removed testes. Results: Transmission electron microscopy revealed severe ultrastructural changes of interstitial tissue and seminiferous epithelium sustained by positive signal for apoptosis. The promatrix metalloproteinase-2 activity and NFkB, Bcl-2 expressions were increased, mainly at 7 days. Conclusion: AgNPs induced severe cell lesions identified even a long time after the exposure.

Characterization and biological effects of Hypericum extracts on experimentally-induced - anxiety, oxidative stress and inflammation in rats

Anxiety disorders can associate with oxidative stress and immune system alterations. Our study aimed to chemically analyze Hypericum maculatum (HM) and Hypericum perforatum (HP) dry extracts and to evaluate their effects along with quercetin (Q), on brain oxidative stress biomarkers: malondialdehyde (MDA), catalase (CAT) and superoxide dismutase (SOD), inflammatory cytokines: interleukin-1α, (IL-1α), IL-1β, regulated on activation normal T cell expressed and secreted (RANTES), interferon (IFN), monocyte chemoattractant protein-1 (MCP1), macrophage inflammatory protein (MIP) and serum corticosterone levels. Nuclear transcription factor κB (NFκB) signaling pathway in the hippocampus and frontal lobe in rats with N-methyl-9H-pyrido[5,4-b]indole-3-carboxamide (FG-7142) experimental-induced anxiety were also investigated. The chemical analyses of total hypericins were performed by spectrophotometric analysis and hypericin, hyperforin and polyphenols derivatives were quantified by chromatographic methods. The animals were divided in 6 groups: carboxymethylcellulose 2% (CMC); CMC + FG; alprazolam (APZ) + FG; Q + FG; HM + FG; HP + FG. APZ (0.08 mg/kg b.w.), Q (30 mg/kg b.w.), HM and HP (350 mg/kg b.w.) were orally administered for 21 days. FG (7.5 mg/kg b.w.) was intraperitoneally (i.p.) injected in a single dose. Q and hypericum extracts (HpE) exerted anti-inflammatory (decreased IL-1α, IL-1β, MCP1, IFN and MIP mainly in hippocampus) and antioxidant effects (decreased MDA levels, increased CAT and SOD activity), enhanced NFκB and pNFκB expressions in the brain and reduced serum corticosterone levels. Our findings suggest that HpE may improve anxiety-like behavior, offer brain protection by modulation of oxidative stress and inflammation, and can contribute to overall biological activity of natural compounds-rich diet.

UV-light mediated green synthesis of silver and gold nanoparticles using Cornelian cherry fruit extract and their comparative effects in experimental inflammation

The purpose of our study is to investigate the comparative effects of materials based on silver and gold nanoparticles functionalized with polyphenols from Cornus Mas extract (AgNPs-CM and AuNPs-CM) in vivo on experimental inflammation. The nanoparticles were obtained at room temperature under UV irradiation and were characterized by different methods: ultraviolet-visible spectroscopy, transmission electron microscopy, X ray diffraction, Fourier transform infrared spectroscopy and dynamic light scattering. The modulatory effects of AgNPs-CM and AuNPs-CM on inflammation were quantified by oxidative stress parameters, pro and anti-inflammatory cytokines levels and apoptosis assessment at 2 h, 24 and 48 h after induction of inflammation with carrageenan in the paw tissue of Wistar rats. Our results showed that silver and gold nanoparticles only partial and for a short period have mobilized the antioxidant defense mechanisms. In addition, they diminished inflammation and apoptosis in the early stage while later, at 48 h, exerted an immunomodulatory effect, activated ERK ½ and induced apoptosis. The photoreduced silver and gold nanoparticles, functionalized with natural compounds, modulated the inflammation in a similar manner in the soft tissue injected with carrageenan. In order to decipher the mechanisms involved in interactions of metallic nanoparticles with biological systems and for a complete assessment of the risks and benefits of these products in clinical practice long term studies are necessary.

The effect of Tropaeolum majus L. on bacterial infections and in vitro efficacy on apoptosis and DNA lesions in hyperosmotic stress

Tropaeolum majus L. (T. majus) or nasturtium is a medicinal plant widespread in the areas with temperate climate, commonly used in culinary and in traditional medicine due to therapeutic properties. In the last few years, various effects of the flowers and leaves of this plant have been studied, but their benefits are not fully known. The aim of the study was to identify the phenolic compounds from T. majus edible flowers in relation with its antioxidant capacity and the antimicrobial activity against different bacteria and Candida albicans. In addition, the impact of natural extract on oxidative stress, inflammation and apoptosis was analysed on human umbilical vein endothelial cells (HUVECs) exposed to normotonic and hypertonic conditions. The major phenolic acids, identified by HPLC-RP with UV detection, were gallic acid, caffeic acid and p-coumaric and predominant flavonoids were quercetin, epicatechin and luteolin. The both fractions of T. majus were rich sources of polyphenols with marked antioxidant activity, evidenced by TEAC or DPPH methods. The extract exhibited a week antibacterial effect on some strains of streptococcus, without antifungal or antibacterial effect on gram negative bacteria. T. majus extract increased the p53 and Bcl-2 expressions and diminished the DNA lesions indicating the protective and antiapoptotic effects in vitro, on endothelial cells exposed to hyperosmotic stress. These experimental findings suggest that T. majus can exert some protection against bacterial infections and reduce apoptosis and DNA lesions in hypertonic conditions.

Effects of different hypoxia degrees on endothelial cell cultures-Time course study

INTRODUCTION

Exposure of the endothelial cells to hypoxia, the decrease in oxygen supply can trigger an endothelial response. This response is involved in inflammatory diseases, tumorigenesis, and also with the micro vascular damage associated with aging. The aim of our study was to determine the hypoxia/re-oxygenation induced response in vitro, using human umbilical vein endothelial cells (HUVEC) cultures, at different time points with focus on cell viability, apoptosis oxidative stress and angiogenesis stimulation.

MATERIALS AND METHODS

Cells were exposed to 10%, 5% or 0% O₂ for 6h, 12h, and 24h. Viability was measured through colorimetry, apoptosis - annexin V-FITC staining, DNA lesions (γH₂AX), endothelial activation (sICAM1), angiogenesis (HIF1α), oxidative stress (malondialdehyde, superoxidismutase and NFκB activation) were determined by ELISA, Western Blot and spectrophotometry.

RESULTS AND DISCUSSION

Hypoxia decreased viability, increased apoptosis, oxidative stress, endothelial activation and angiogenesis, depending on O₂ concentration and time exposure. Short exposures to 5% and 10% O₂, efficiently activated anti-apoptotic mechanisms through NFκB activation, HIF1α and γH₂AX related DNA damage repair pathways. However, severe hypoxia and longer exposures to mild hypoxia induced high oxidative stress related damage and eventually led to apoptosis, through strong increases of HIF1α and accumulating DNA lesions.

The effects of silver nanoparticles on behavior, apoptosis and nitro-oxidative stress in offspring Wistar rats

Aim: To investigate the comparative effects of prenatal exposure to silver nanoparticles (AgNPs) functionalized with citrate and polyphenols on spatial cognition and also on nitro-oxidative stress and apoptosis in the hippocampus and cerebellum of offsprings. Materials & methods: Pregnant Wistar rats were orally administered substances from day 10 of gestation until day 21. Six weeks postpartum, six male offsprings from each group were used for behavioral evaluation and determination of oxidative stress and apoptosis. Results: Both groups exhibited hyperactivity and anxiety especially after AgNPs-Sambucus nigra L. administration. AgNPs-S. nigra L. group showed increase in induced nitric oxide synthase activity and decrease in superoxide dismutase activity and apoptosis in the hippocampus, while AgNPs-citrate coated administration exerted a moderate toxicity and induced apoptosis. Conclusion: AgNPs functionalized with natural extracts had a lower toxicity than citrate-coated silver particles.

In vitro and in vivo anti-inflammatory properties of green synthesized silver nanoparticles using Viburnum opulus L. fruits extract

A green, rapid and cost effective method for the bio-synthesis of silver nanoparticles (AgNPs), using polyphenols present in European cranberry bush fruit extracts was developed. The obtained AgNPs were characterized by ultra-violet visible spectroscopy (UV-VIS), Fourier transform - infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and X-ray diffraction patterns (XRD). The average size of the spherical AgNPs was found to be 25nm. The anti-inflammatory effect of the biomaterials was investigated, both in vitro (on HaCaT cell line, exposed to UVB radiation) and in vivo (on acute inflammation model in Wistar rats). Our results support the conclusion that the photosynthesized silver nanoparticles present a potent anti-inflammatory activity and could be successfully used as therapeutic tools for treatment of inflammation.

Combined regimen of photodynamic therapy mediated by Gallium phthalocyanine chloride and Metformin enhances anti-melanoma efficacy

BACKGROUND

Melanoma therapy is challenging, especially in advanced cases, due to multiple developed tumor defense mechanisms. Photodynamic therapy (PDT) might represent an adjuvant treatment, because of its bimodal action: tumor destruction and immune system awakening. In this study, a combination of PDT mediated by a metal substituted phthalocyanine-Gallium phthalocyanine chloride (GaPc) and Metformin was used against melanoma. The study aimed to: (1) find the anti-melanoma efficacy of GaPc-PDT, (2) assess possible beneficial effects of Metformin addition to PDT, (3) uncover some of the mechanisms underlining cell killing and anti-angiogenic effects.

METHODS

Two human lightly pigmented melanoma cell lines: WM35 and M1/15 subjected to previous Metformin exposure were treated by GaPc-PDT. Cell viability, death mechanism, cytoskeleton alterations, oxidative damage, were assessed by means of colorimetry, flowcytometry, confocal microscopy, spectrophotometry, ELISA, Western Blotting.

RESULTS

GaPc proved an efficient photosensitizer. Metformin addition enhanced cell killing by mechanisms dependent on the cell line, namely apoptosis in the metastatic M1/15 and necrosis in the radial growth phase, WM35. Cell death mechanism relied on the inhibition of nuclear transcription factor (NF)-κB activation and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) sensitization, leading to TRAIL and TNF-α induced apoptosis. Metformin diminished the anti-angiogenic effect of PDT.

CONCLUSIONS

Metformin addition to GaPc-PDT increased tumor cell killing through enhanced oxidative damage and induction of proapoptotic mechanisms, but altered PDT anti-angiogenic effects.

GENERAL SIGNIFICANCE

Combination of Metformin and PDT might represent a solution to enhance the efficacy, leading to a potential adjuvant role of PDT in melanoma therapy.

Toxicity and efficiency study of plant extracts-based bleaching agents

OBJECTIVES

Tooth bleaching is one of the most required dental esthetic treatments. However, it can generate side effects like oral irritation, enamel alteration, tooth sensitivity, especially caused by hydrogen peroxide, the main bleaching component of the commercial products. Therefore, development of new tooth bleaching agents, based on natural products, with comparable esthetic results and lower side effects is needed. The aim of this study was to evaluate the biological effects and bleaching efficacy of four experimental bleaching agents, derived from fruit juices, against the commercially available Opalescence (Ultradent, USA).

MATERIALS AND METHODS

Organic acid composition of the gels was characterized by HPLC. Bleaching efficiency was tested by spectrophotometry on composite restorative materials. Biological testing was done in vitro, on human fibroblasts. Cells were exposed to dilutions of the bleaching gel-conditioned medium. Viability was measured by MTS, apoptosis by FACS-AnnexinV FITC/Propidium iodide, NF-kB activation by western blot, malondyaldehide, and superoxide dismutase activity by spectrophotometry.

RESULTS

All gels exhibited physical stability and dental bleaching capabilities. Experimental gels induced significantly better viability and apoptosis rates, lower lipid peroxidation, and increased antioxidant defense, compared to Opalescence.

CONCLUSIONS

The studied experimental gel formulations exhibited a good safety profile in vitro, as well as bleaching efficiency on restorative composite materials.

CLINICAL RELEVANCE

These data open new possibilities for the use of new natural products in dental bleaching treatments that can insure significant esthetic results and lower side effects.

Cytotoxicity assessment of graphene-based nanomaterials on human dental follicle stem cells

Graphene-oxide (GO) and its most encountered derivatives, thermally reduced graphene oxide (TRGO) and nitrogen-doped graphene (N-Gr), were synthesized and structurally characterized by spectroscopic techniques, like Raman and (13)C MAS solid state NMR. Several biological effects (cytotoxicity, oxidative stress induction, and cellular and mithocondrial membrane alterations) induced by such graphene-based materials on human dental follicle stem cells were investigated. Graphene oxide shows the lowest cytotoxic effect, followed by the nitrogen-doped graphene, while thermally reduced graphene oxide exhibits high cytotoxic effects. Graphene oxide induces oxidative stress without causing cell membrane damage. Nitrogen-doped graphene shows a slight antioxidant activity; however, at high doses (20 and 40 μg/ml) it causes membrane damage. Both graphene oxide and nitrogen-doped graphene seem to be valuable candidates for usage in dental nanocomposites.

Photodynamic therapy of melanoma using new, synthetic porphyrins and phthalocyanines as photosensitisers - a comparative study

Melanoma, a cancer that arises from melanocytes, is one of the most unresponsive cancers to known therapies and has a tendency to produce early metastases. Several studies showed encouraging results of the efficacy of photodynamic therapy (PDT) in melanoma, in different experimental settings in vitro and in vivo, as well as several clinical reports.

Comparative evaluation by scanning confocal Raman spectroscopy and transmission electron microscopy of therapeutic effects of noble metal nanoparticles in experimental acute inflammation

A test of Raman spectroscopy as a technique to diagnose inflammatory conditions and differentiate the effect of treatments with silver and gold nanoparticles conjugated with natural extracts compared with microscopy in experimental acute inflammation.

Biphasic pro-melanogenic and pro-apoptotic effects of all-trans-retinoic acid (ATRA) on human melanocytes: time-course study

BACKGROUND

The effects of retinoids on melanogenesis and their mechanism as depigmenting agents in topical therapy have not been fully elucidated. Conflicting data about their impact on melanogenic pathways have been reported.

OBJECTIVE

To investigate the effects of all-trans-retinoic acid (ATRA) on normal human melanocytes from Caucasian subjects.

METHODS

We assessed ATRA's cytotoxicity by measuring viability with a cell proliferation assay, and apoptotic effects using Annexin V and γ-H2AX markers. ATRA's melanogenic activity was investigated based on spectrophotometric measurement of melanin content and tyrosinase enzymatic activity. Tyrosinase expression was assessed by Western blotting. We tested the antioxidant activity of superoxide dismutase (SOD) and catalase (CAT) in melanocytes using a spectrophotometric assay.

RESULTS

Of the concentrations tested in this 72h time-course study, the 1.0μM ATRA had a well-defined two-stage pro-melanogenic and pro-apoptotic effect on melanocytes. In the first 6h, treated cells showed significant increase (p≤0.01) of melanin content, tyrosinase, SOD, and CAT activities compared to the controls. While overall tyrosinase expression was not affected by ATRA, all other tested parameters decreased progressively beyond the short-term point of 6h. ATRA treatment of over 6h induced melanocyte apoptosis, as shown by the time-dependent decrease in cell viability, coupled with significant increase in Annexin V positive cells and nuclear accumulation of γ-H2AX foci.

CONCLUSION

The results obtained using this testing platform show a biphasic ATRA action: immediate pro-melanogenic effect and longer-term exposure pro-apoptotic activity. These data qualify ATRA as a potent tool to better understand the mechanisms that regulate the pigmentary system.

Photodynamic therapy in melanoma--an update

Melanoma, a cancer that arises from melanocytes is one of the most unresponsive cancers to known therapies. Several studies showed encouraging results of the efficacy of photodynamic therapy (PDT) using different experimental settings in vitro and in vivo as well as a few clinical reports, suggesting a possible role as an adjuvant therapy in the management of advanced melanoma (stage III and IV). In experimental settings, PDT using different protocols on human and mice melanoma cells induced significant apoptosis, necrosis, tumor growth arrest and prolonged the survival of the animals, but seldom achieved complete remission and/or was followed by recurrence and side effects. Clinical reports showed regression of choroidal melanoma and skin melanoma metastasis following PDT. PDT consists in administration of a photosensitizer, which undergoes excitation after suitable irradiation emitted from a light source and generates singlet oxygen (¹O₂) and other cytotoxic oxygen species such as superoxide anion radical (O₂·⁻) and hydroxyl radical (OH·). The antitumor effects result from the combination of direct tumor cell photodamage, destruction of tumor vasculature and activation of an immune response. To increase the effectiveness of PDT in melanoma, the therapy has to overcome the protective mechanisms like pigmentation and increased oxidative stress defense, possibly through inhibition of melanogenesis and melanosome targeted photosensitizers. The optimal protocols for tumor and vascular targeted PDT could destroy melanoma and endothelial tumor cells and activate the immune response, thus increasing the overall efficacy. Combination of PDT with immune stimulation therapies might increase the efficiency in destroying the initial tumor as well as micro metastases and decrease the melanoma relapses.

The effects of grape seeds polyphenols on SKH-1 mice skin irradiated with multiple doses of UV-B

The study investigated the protective activity of red grape seeds (Vitis vinifera L, Burgund Mare variety) (BM) extracts in vivo on multiple doses of ultraviolet radiation (UV)-B-induced deleterious effects in SKH-1 mice skin. Eighty 8-weeks-old female SKH-1 mice were divided into 8 groups: control, vehicle, UV-B irradiated, vehicle+UV-B irradiated, BM 2.5mg polyphenols (PF)/cm(2)+UV-B irradiated, BM 4 mg PF/cm(2)+UV-B irradiated, UV-B+BM 2.5mg PF/cm(2), UV-B+BM 4 mg PF/cm(2). The extract was applied topically before or after each UV-B exposure (240 mJ/cm(2)), for 10 days consecutively. The antioxidant activity of BM extract is higher than gallic acid (k(BM)=0.017, k(gallic acid)=0.013). Multiple doses of UV-B generated the formation of cyclobutane pyrimidine dimers (CPDs) and sunburn cells, increased glutathione peroxidase (GPx) and catalase (CAT) activities respectively glutathione (GSH) and IL-1β levels in skin. In group treated with 2.5mg PF/cm(2) before UV-B irradiation BM extract inhibited UV-B-induced sunburn cells, restored the superoxide dismutase (MnSOD) activity, increased insignificantly CAT and GPx activities and reduced IL-1β level. The BM 4.0 mg PF/cm(2) treatment decreased GSH level and reduced the percentage of CPDs positive cells in skin. Both doses of BM extract administered after UV-B irradiation increased the MnSOD and GPx activities and reduced the formation of sunburn cells in skin. Our results suggest that BM extract might be a potential chemo-preventive candidate in reducing the oxidative stress and apoptosis induced by multiple doses of UV-B in skin.

Photodamaging effects of porphyrins and chitosan on primary human keratinocytes and carcinoma cell cultures

BACKGROUND

Photodynamic therapy (PDT) is a non-surgical method for treating non-melanoma skin cancer and precancerous lesions which involves the activation of a photosensitizer by visible light to produce activated oxygen species within target cells, resulting in the destruction of the latter. The present study evaluates the effect of PDT on primary normal and basal cell carcinoma cultures in vitro.

METHODS

Primary human keratinocytes and carcinoma cell cultures were exposed to various concentrations of 5,10,15,20-tetra-(para-methoxyphenyl) porphyrin (TMP) and its zinc compound (Zn-TMP) for 24 hours, with or without chitosan, and then irradiated using a PDT lamp (630 nm, 6 J/cm(2)). The effects of PDT were assessed using a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay and an immunocytochemical method with Annexin V-FITC for detecting apoptosis.

RESULTS

Both tested substances, TMP and Zn-TMP, had a phototoxic effect on primary human carcinoma cell cultures in concentrations of 1-100 μg/ml, which positively correlated with the concentration of the photosensitizer. There was no phototoxic effect on primary keratinocytes, probably because of the preferential accumulation of photosensitizing substances in tumoral cells. Administration of chitosan in association with photosensitizing substances increased cell viability compared with photosensitizers alone, exerting a cytoprotective effect.

CONCLUSIONS

The study demonstrates that the photodynamic activity of TMP and its metalloporphyrin derivative is limited to primary human carcinoma cells and suggests that these porphyrins could be efficiently used in PDT in vivo.

Alternative splicing determines mRNA translation initiation and function of human K(2P)10.1 K+ channels

Potassium-selective ion channels regulate cardiac and neuronal excitability by stabilizing the resting membrane potential and by modulating shape and frequency of action potentials. The delicate control of membrane voltage requires structural and functional diversity of K+ channel subunits expressed in a given cell. Here we reveal a previously unrecognized biological mechanism. Tissue-specific mRNA splicing regulates alternative translation initiation (ATI) of human K(2P)10.1 K+ background channels via recombination of 5 nucleotide motifs. ATI-dependent expression of full-length protein or truncated subunits initiated from two downstream start codons determines macroscopic current amplitudes and biophysical properties of hK(2P)10.1 channels. The interaction between hK(2P)10.1 mRNA splicing, translation and function increases K+ channel complexity and is expected to contribute to electrophysiological plasticity of excitable cells.

Chemopreventive effects of Calluna vulgaris and Vitis vinifera extracts on UVB-induced skin damage in SKH-1 hairless mice

Solar ultraviolet radiation (UV) is a major cause of non-melanoma skin cancer in humans. Photochemoprevention with natural products represents a simple but very effective strategy in the management of cutaneous neoplasia. The study investigated the protective activity of Calluna vulgaris (Cv) and red grape seeds (Vitis vinifera L, Burgund Mare variety) (BM) extracts in vivo on UVB-induced deleterious effects in SKH-1 mice skin. Forty SKH-1 mice were randomly divided into 4 groups (n=10): control, UVB irradiated, Cv + UVB irradiated, BM+UVB irradiated. Both extracts were applied topically on the skin in a dose of 4 mg/40 μl/cm(2) before UVB exposure - single dose. The effects were evaluated in skin 24 hours after irradiation through the presence of cyclobutane pyrimidine dimers (CPDs) and sunburn cells, tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6 levels. The antioxidant activity of BM extract was higher than those of Cv extract as determined using stable free radical DPPH assay and ABTS test. One single dose of UVB generated formation of CPDs (p<0.0001) and sunburn cells (p<0.0002) and increased the cytokine levels in skin (p<0.0001). Twenty hours following irradiation BM extract inhibited UVB-induced sunburn cells (p<0.02) and CPDs formation (p<0.0001). Pretreatment with Cv and BM extracts resulted in significantly reduced levels of IL-6 and TNF-α compared with UVB alone (p<0.0001). Our results suggest that BM extracts might be a potential candidate in preventing the damages induced by UV in skin.

The role of ultraviolet radiation and tyrosine stimulated melanogenesis in the induction of oxidative stress alterations in fair skin melanocytes

BACKGROUND

Melanocytes are producing melanin after UV irradiation as a defense mechanism. However, UV-induced damage is involved in melanoma initiation, depending on skin phototype. Melanocytes seem to be extremely susceptible to free radicals. Their main enzymatic antioxidants are superoxide dismutase and catalase.

AIM

To study how melanin synthesis modulates the activity of the oxidative stress defense enzymes and cell proliferation after UV induced cell damage.

METHODS

Normal human melanocyte cultures from fair skin individuals were exposed to high levels of L-tyrosine and irradiated, with 20, 30, 40 mJ/cm2 UVA, and respective UVB. Proliferation was measured using a MTS assay; viability was assessed by trypan blue exclusion dye method. Spectrophotometrical methods were used to determine total melanin content, the enzymatic activity of tyrosinase, superoxide dismutase and catalase.

RESULTS

Tyrosine had a negative effect on proliferation, enhanced with time elapsed. Overall, UV irradiation decreased proliferation. UVA increased proliferation relative to UVB in the cultures exposed for a longer time to high (2 mM) tyrosine concentration. There were no proliferation differences between UVA and UVB irradiation in lower tyrosine concentration exposed melanocytes. Both, UV irradiation and tyrosine increased melanogenesis. Exposure of the melanocytes to increased levels of tyrosine in medium (0.5 mM and 1 mM) and UV irradiation enhanced the activity of superoxide dismutase and catalase. The enzymes showed a high activity rate in melanocytes while exposed for a short time to 2 mM tyrosine, but their activity was dramatically decreased with longer tyrosine exposure and UV irradiation.

CONCLUSION

Our data indicate that in low phototype melanocytes, melanogenesis, either following UV irradiation, or tyrosine exposure, especially in high concentrations, was detrimental for the cells by reducing the activity of catalase and superoxidedismutase, the natural antioxidants. UVA was more efficient in stimulating the activity of superoxide dismutase and catalase but also in depleting the reserves of the enzymatic defense against oxidative stress, especially catalase, than UVB. This physiologic response to UV light can be considered as an adjunctive risk factor for people with low phototype for developing a melanoma, when exposed to UV irradiation.