Vassiliki Pletsa

Dr. Vassiliki Pletsa

Institute of Chemical Biology, National Hellenic Research Foundation, 48 Vas. Constaninou Ave., 11635 Athens, Greece
orcid

Research Focus & Metrics

Academic Career Length

35Years (1992-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 December 2020 in Nanomaterials
Verified
Journal Article
Open access
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SDSOTIRIA DEMISLI
SOTIRIA DEMISLI
Evgenia MitsouEvgenia Mitsou
Evgenia Mitsou
VPVassiliki Pletsa
Vassiliki Pletsa
AXAristotelis Xenakis
Aristotelis Xenakis
VPVassiliki Papadimitriou
Vassiliki Papadimitriou
Biocompatible nanoemulsions and nanoemulsion-based hydrogels were formulated for the encapsulation and delivery of vitamin D3 and curcumin. The aforementioned systems were structurally studied applying dynamic light scattering (DLS), electron paramagnetic resonance (EPR) spectroscopy and viscometry. In vitro studies were conducted using Franz diffusion cells to investigate the release of the bioactive compounds from the nanocarriers. The cytotoxicity of the nanoemulsions was investigated using the thiazolyl blue tetrazolium bromide (MTT) cell proliferation assay and RPMI 2650 nasal epithelial cells as in vitro model. DLS measurements showed that vitamin D3 and curcumin addition in the dispersed phase of the nanoemulsions caused an increase in the size of the oil droplets from 78.6 ± 0.2 nm to 83.6 ± 0.3 nm and from 78.6 ± 0.2 nm to 165.6 ± 1.0 nm, respectively. Loaded nanoemulsions, in both cases, were stable for 60 days of storage at 25 °C. EPR spectroscopy revealed participation of vitamin D3 and curcumin in the surfactants monolayer. In vitro release rates of both lipophilic compounds from the nanoemulsions were comparable to the corresponding ones from the nanoemulsion-based hydrogels. The developed o/w nanoemulsions did not exhibit cytotoxic effect up to the concentration threshold of 1 mg/mL in the cell culture medium.

18 June 2020 in Molecules
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Journal Article
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EMEvdokia K. Mitsou
Evdokia K. Mitsou
Georgia SaxamiGeorgia Saxami
Georgia Saxami
ESEmmanuela Stamoulou
Emmanuela Stamoulou
EKEvangelia N. Kerezoudi
Evangelia N. Kerezoudi
ETEirini Terzi
Eirini Terzi
AKAdamantini Kyriacou
Adamantini Kyriacou
Alterations of gut microbiota are evident during the aging process. Prebiotics may restore the gut microbial balance, with β-glucans emerging as prebiotic candidates. This study aimed to investigate the impact of edible mushrooms rich in β-glucans on the gut microbiota composition and metabolites by using in vitro static batch culture fermentations and fecal inocula from elderly donors (n = 8). Pleurotus ostreatus, P. eryngii, Hericium erinaceus and Cyclocybe cylindracea mushrooms derived from various substrates were examined. Gut microbiota composition (quantitative PCR (qPCR)) and short-chain fatty acids (SCFAs; gas chromatography (GC)) were determined during the 24-h fermentation. P. eryngii induced a strong lactogenic effect, while P. ostreatus and C. cylindracea induced a significant bifidogenic effect (p for all <0.05). Furthermore, P. eryngii produced on wheat straw and the prebiotic inulin had comparable Prebiotic Indexes, while P. eryngii produced on wheat straw/grape marc significantly increased the levels of tested butyrate producers. P. ostreatus, P. eryngii and C. cylindracea had similar trends in SCFA profile; H. erinaceus mushrooms were more diverse, especially in the production of propionate, butyrate and branched SCFAs. In conclusion, mushrooms rich in β-glucans may exert beneficial in vitro effects in gut microbiota and/or SCFAs production in elderly subjects.

16 June 2019 in Catalysts
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Journal Article
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GKGeorgios Koutrotsios
Georgios Koutrotsios
MPMarianna Patsou
Marianna Patsou
EMEvdokia K. Mitsou
Evdokia K. Mitsou
GBGeorgios Bekiaris
Georgios Bekiaris
MKMARIA KOTSOU
MARIA KOTSOU
GZGeorgios Zervakis
Georgios Zervakis
The successful management of olive by-products constitutes a major challenge due to their huge volume, high organic content, and toxicity. Olive-mill wastes (TPOMW) and olive pruning residues (OLPR) were evaluated as substrates for the cultivation of Ganoderma lucidum and Pleurotus ostreatus. Chemical composition, glucans, total phenolic content, and antioxidant activity were measured in mushrooms, and their prebiotic potential was assessed by examining their effect on the growth of four intestinal bacteria. Several substrates based on olive by-products had a positive impact on P. ostreatus mushroom production, whereas only one performed adequately for G. lucidum. Increased ratios of OLPR to wheat-straw resulted in an increase of crude protein content in P. ostreatus fruit-bodies by up to 42%, while G. lucidum mushrooms from OLPR-based substrates exhibited an up to three-fold increase in α-glucan, or a significant enhancement of β-glucan content, when compared to beech sawdust (control). The mushrooms’ FTIR spectra confirmed the qualitative/quantitative differentiation detected by standard assays. In regard to prebiotic properties, mushrooms powder supported or even enhanced growth of both Lactobacillus acidophilus and L. gasseri after 24/48 h of incubation. In contrast, a strain-specific pattern was observed in bifidobacteria; mushrooms hindered Bifidobacterium bifidum growth, whereas they supported a similar-to-glucose growth for B. longum.

1 June 2020 in Colloids and Surfaces B: Biointerfaces
Verified
Journal Article
Closed access
Evgenia MitsouEvgenia Mitsou
Evgenia Mitsou
VPVassiliki Pletsa
Vassiliki Pletsa
GSGeorge T. Sotiroudis
George T. Sotiroudis
PPPierre Panine
Pierre Panine
Maria ZoumpaniotiMaria Zoumpanioti
Maria Zoumpanioti
AXAristotelis Xenakis
Aristotelis Xenakis

23 April 2015 in Experimental Biology and Medicine
Verified
Journal Article
Closed access
CMChristina Michailidi
Christina Michailidi
STStamatios Theocharis
Stamatios Theocharis
GTGerasimos Tsourouflis
Gerasimos Tsourouflis
VPVassiliki Pletsa
Vassiliki Pletsa
GKGregorios Kouraklis
Gregorios Kouraklis
CTConstantinos Troungos
Constantinos Troungos
Colorectal cancer (CRC) is the third most common cancer in men and the second in women worldwide. CRC development is the result of genetic and epigenetic alterations accumulation in the epithelial cells of colon mucosa. In the present study, DNA methylation, an epigenetic event, was evaluated in tumoral and matching normal epithelium in a cohort of 61 CRC patients. The results confirmed and expanded knowledge for the tumor suppressor genes hMLH1, MGMT, APC, and CDH1. Promoter methylation was observed for all the examined genes in different percentage. A total of 71% and 10% of the examined cases were found to be methylated in two or more and in all genes, respectively. mRNA and protein levels were also evaluated. Promoter methylation of hMLH1, MGMT, APC, and CDH1 genes was present at the early stages of tumor’s formation and it could also be detected in the normal mucosa. Correlations of the methylated genes with patient’s age and tumor’s clinicopathological characteristics were also observed. Our findings suggest that DNA methylation is a useful marker for tumor progression monitoring and that promoter methylation in certain genes is associated with more advanced tumor stage, poor differentiation, and metastasis.

22 March 2022 in Journal of Fungi
Verified
Journal Article
Open access
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Marigoula VlassopoulouMarigoula Vlassopoulou
Marigoula Vlassopoulou
NPNikolaos Paschalidis
Nikolaos Paschalidis
ASAlexander Loris Savvides
Alexander Loris Savvides
Georgia SaxamiGeorgia Saxami
Georgia Saxami
EMEvdokia K. Mitsou
Evdokia K. Mitsou
VPVassiliki Pletsa
Vassiliki Pletsa
Recent studies have revealed the crucial role of several edible mushrooms and fungal compounds, mainly polysaccharides, in human health and disease. The investigation of the immunomodulating effects of mushroom polysaccharides, especially β-glucans, and the link between their anticancer and immunomodulatory properties with their possible prebiotic activity on gut micro-organisms has been the subject of intense research over the last decade. We investigated the immunomodulating effects of Pleurotus eryngii mushrooms, selected due to their high β-glucan content, strong lactogenic effect, and potent geno-protective properties, following in vitro fermentation by fecal inocula from healthy elderly volunteers (>60 years old). The immunomodulating properties of the fermentation supernatants (FSs) were initially investigated in U937-derived human macrophages. Gene expression as well as pro- (TNF-α, IL-1β) and anti-inflammatory cytokines (IL-10, IL-1Rα) were assessed and correlated with the fermentation process. The presence of P. eryngii in the fermentation process led to modifications in immune response, as indicated by the altered gene expression and levels of the cytokines examined, a finding consistent for all volunteers. The FSs immunomodulating effect on the volunteers’ peripheral blood mononuclear cells (PBMCs) was verified through the use of cytometry by time of flight (CyTOF) analysis.