Valeria Petrova

Mrs. Valeria Petrova

Veterinary Physiology, Trakia University, Stara Zagora, Bulgaria
orcid

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

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

Representative Publications

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1 January 2023 in Foods
Verified
Journal Article
Open access
PDF file
EVEkaterina Vachkova
Ekaterina Vachkova
VPValeria Petrova
Valeria Petrova
NGNatalia Tsoneva Grigorova
Natalia Tsoneva Grigorova
ZIZhenya Ivanova
Zhenya Ivanova
Georgi BeevGeorgi Beev
Georgi Beev
Probiotics such as Lactobacillus spp. could modulate the intestinal microbiota composition, supporting gastrointestinal tract barrier function and benefiting human health. To evaluate the anticancer and probiotic properties of potentially active autochthonous Lacticaseibacillus paracasei strains on proliferating and differentiated enterocytes, human colon adenocarcinoma cell line HT29 was used as a model. The lactic acid bacteria (LAB) were isolated from new ecological niches—mountain anthills populated by redwood ants (Formica rufa L.). Human colorectal adenocarcinoma cells (HT29, ATCC, HTB-38™) were treated for twenty-four hours with supernatants (SNs) derived from four strains of Lacticaseibacillus paracasei: P4, C8, C15 and M2.1. An MTT assay, alkaline phosphatase activity, IAP, Bax and Bcl-2 gene expression analysis (RT-qPCR) and the Bax/Bcl-2 ratio were evaluated. The MTT assay revealed that the observed effects varied among groups. However, 10% neutralized supernatants from P4, C8, C15 and M2.1 strains did not show cytotoxic effects. In contrast to non-differentiated cells, a significant (p < 0.001) rise in ALP activity in all treatments, with an average of 18%, was established in differentiated cells. The IAP expression was remarkably downregulated in the differentiated M2.1 group (p < 0.05) and upregulated in the non-differentiated P4 (p < 0.05) and M2.1 (p < 0.05) groups. The Bax/Bcl-2 quantity expression ratio in P4 was significantly (p < 0.05) upregulated in proliferating cancer cells, but in P4- and M2.1-differentiated cells these values were downregulated (p < 0.05). The obtained results indicate that the isolated L. paracasei strains possess anticancer and probiotic properties and could be used as additives for functional dairy foods and thus benefit human health.

12 April 2024 in Toxicology in Vitro
Verified
Journal Article
Closed access
ATAnna Tyumentseva
Anna Tyumentseva
EKElena Khilazheva
Elena Khilazheva
VPValeria Petrova
Valeria Petrova
SSSergey Stolyar
Sergey Stolyar

Verified
Journal Article
Open access
PDF file
NGNatalia Tsoneva Grigorova
Natalia Tsoneva Grigorova
ZIZhenya Ivanova
Zhenya Ivanova
EVEkaterina Vachkova
Ekaterina Vachkova
VPValeria Petrova
Valeria Petrova
TPToncho Penev
Toncho Penev
The signaling pathway of fatty acids in the context of obesity is an extensively explored topic, yet their primary mechanism of action remains incompletely understood. This study aims to examine the effect of docosahexaenoic acid (DHA) on some crucial aspects of adipogenesis in differentiating 3T3-L1 cells, using palmitic acid-treated (PA), standard differentiated, and undifferentiated adipocytes as controls. Employing 60 µM DHA or PA, 3T3-L1 preadipocytes were treated from the onset of adipogenesis, with negative and positive controls included. After eight days, we performed microscopic observations, cell viability assays, the determination of adiponectin concentration, intracellular lipid accumulation, and gene expression analysis. Our findings demonstrated that DHA inhibits adipogenesis, lipolysis, and glucose uptake by suppressing peroxisome proliferator-activated receptor gamma (Pparg) and G-protein coupled receptor 120 (Gpr120) gene expression. Cell cytotoxicity was ruled out as a causative factor, and β-oxidation involvement was suspected. These results challenge the conventional belief that omega-3 fatty acids, acting as Pparg and Gpr120 agonists, promote adipogenesis and enhance insulin-dependent glucose cell flux. Moreover, we propose a novel hypothesis suggesting the key role of the co-repressor G protein pathway suppressor 2 in mediating this process. Additional investigations are required to elucidate the molecular mechanisms driving DHA’s anti-adipogenic effect and its broader health implications.

12 May 2023 in Veterinary Sciences
Verified
Journal Article
Open access
PDF file
VPValeria Petrova
Valeria Petrova
EVEkaterina Vachkova
Ekaterina Vachkova
Adipose tissue is recognized as the major endocrine organ, potentially acting as a source of mesenchymal stem cells for various applications in regenerative medicine. Athletic horses are often exposed to traumatic injuries, resulting in severe financial losses. The development of adipose-derived stem cells’ regenerative potential depends on many factors. The extraction of stem cells from subcutaneous adipose tissue is non-invasive, non-traumatic, cheaper, and safer than other sources. Since there is a lack of unique standards for identification, the isolated cells and applied differentiation protocols are often not species-specific; therefore, the cells cannot reveal their multipotent properties, so their stemness features remain questionable. The current review discusses some aspects of the specificity of equine adipose stem cells concerning their features, immunophenotyping, secretome profile, differentiation abilities, culturing conditions, and consequent possibilities for clinical application in concrete disorders. The presented new approaches elucidate the possibility of the transition from cell-based to cell-free therapy with regenerative purposes in horses as an alternative treatment to cellular therapy. In conclusion, their clinical benefits should not be underestimated due to the higher yield and the physiological properties of adipose-derived stem cells that facilitate the healing and tissue regeneration process and the ability to amplify the effects of traditional treatments. More profound studies are necessary to apply these innovative approaches when treating traumatic disorders in racing horses.

11 January 2026 in Biomedicines
Verified
Journal Article
Open access
PDF file
ZIZhenya Ivanova
Zhenya Ivanova
VPValeria Petrova
Valeria Petrova
BTBetina Todorova Todorova
Betina Todorova Todorova
TPToncho Penev
Toncho Penev
NGNatalia Tsoneva Grigorova
Natalia Tsoneva Grigorova
Background/Objectives: Advanced 3D cell culture techniques enhance the physiological relevance of in vitro models, while supporting the 3Rs principles (Reduction, Refinement, and Replacement) of animal experimentation. In this context, 3D collagen-based systems mimic key extracellular matrix properties, enabling more accurate cellular organization and phenotype. However, changes in culture dimensionality can affect RT-qPCR reference gene stability, underscoring the need for careful validation when combining 2D and 3D systems. Methods: AML12 cells were cultured for 7 days under different 2D and collagen-based 3D conditions. The expression stability of nine candidate housekeeping genes was systematically evaluated using established algorithms (BestKeeper, NormFinder, geNorm, RefFinder, and ΔCt method), followed by inter-group statistical and correlation analyses of raw Ct values. Albumin gene expression was used as a target gene. Results: Although all candidate genes initially met acceptable variability thresholds, a stepwise, exclusion-based analysis revealed distinct performance differences. Hprt, Ppia, and Actb emerged as the most stable, showing no intra-group variability or interaction with Albumin expression. Nevertheless, Ywhaz and Rplp0, despite their high stability, were compromised by significant correlation with Albumin. Furthermore, Ywhaz showed significant downregulation under 3D culture conditions. B2M, Gapdh, 18S, and Hmbs exhibited increased variability, likely reflecting metabolic and microenvironmental heterogeneity associated with prolonged 2D cultivation of AML12 cells. Conclusions: Overall, this study highlights the importance of context-dependent, exclusion-based reference gene validation when comparing 2D and 3D models, and demonstrates a new approach for reliable gene expression normalization in complex in vitro culture systems.

21 August 2025 in Biomedicines
Verified
Journal Article
Open access
PDF file
ZIZhenya Ivanova
Zhenya Ivanova
NGNatalia Tsoneva Grigorova
Natalia Tsoneva Grigorova
VPValeria Petrova
Valeria Petrova
EVEkaterina Vachkova
Ekaterina Vachkova
Georgi BeevGeorgi Beev
Georgi Beev
Background: Postbiotics with anti-adipogenic properties can significantly modify adipocyte metabolism by influencing key cellular pathways involved in lipid accumulation. In preliminary in vitro studies, it is essential to monitor various cellular and subcellular variables, including gene expression and protein synthesis potential, through RT-qPCR analysis. It is also crucial to select internal controls carefully and evaluate their stability for effective normalization and accurate interpretation of the results. Methods: In this study, we assessed the stability of six commonly used housekeeping genes: GAPDH, Actb, HPRT, HMBS, 18S, and 36B4. We analyzed their variability in mature 3T3-L1 adipocytes treated with supernatants from newly isolated Lacticaseibacillus paracasei strains. Our analysis combined classical statistical methods, a ∆Ct analysis, and software algorithms such as geNorm, NormFinder, BestKeeper, and RefFinder. Results: Our stepwise, multiparameter strategy for selecting reference genes led to the exclusion of Actb and 18S as the most variable reference genes. We identified HPRT as the most stable internal control. Additionally, HPRT and HMBS emerged as a stable pair, while the recommended triplet of genes for reliable normalization consists of HPRT, 36B4, and HMBS. Conclusions: The widely used putative genes in similar studies—GAPDH and Actb—did not confirm their presumed stability, which once again emphasizes the need for experimental validation of internal controls to increase the accuracy and reliability of gene expression. Combining a unique biological model—postbiotic-treated adipocytes—with multiple algorithms integrated into a single workflow allows us to provide a methodological template applicable to similar nutritional and metabolic research settings.