Miglena Nikolova

Dr. Miglena Nikolova


Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

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

Representative Publications

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Journal Article
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BGBistra Galunska
Bistra Galunska
YYYoto Yotov
Yoto Yotov
MNMiglena Nikolova
Miglena Nikolova
AAAtanas Angelov
Atanas Angelov
One mechanism to regulate pathological vascular calcification (VC) is its active inhibition. Loss or inactivation of endogenic inhibitors is a major inductor of VC. Such inhibitors are proteins rich in gamma-glutamyl residues (Gla-proteins), whose function strongly depends on vitamin K. The current narrative review is focused on discussing the role of extrahepatic vitamin K-dependent Gla-proteins (osteocalcin, OC; matrix Gla-protein, MGP; Gla-rich protein, GRP) in cardio-vascular pathology. Gla-proteins possess several functionally active forms whose role in the pathogenesis of VC is still unclear. It is assumed that low circulating non-phosphorylated MGP is an indicator of active calcification and could be a novel biomarker of prevalent VC. High circulating completely inactive MGP is proposed as a novel risk factor for cardio-vascular events, disease progression, mortality, and vitamin K deficiency. The ratio between uncarboxylated (ucOC) and carboxylated (cOC) OC is considered as an indicator of vitamin K status indirectly reflecting arterial calcium. Despite the evidence that OC is an important energy metabolic regulator, its role on global cardio-vascular risk remains unclear. GRP acts as a molecular mediator between inflammation and calcification and may emerge as a novel biomarker playing a key role in these processes. Gla-proteins benefit clinical practice as inhibitors of VC, modifiable by dietary factors.

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Maria RadanovaMaria Radanova
Maria Radanova
GMGalya Mihaylova
Galya Mihaylova
Oskan Bahidinov TasinovOskan Bahidinov Tasinov
Oskan Bahidinov Tasinov
DIDesislava Ivanova
Desislava Ivanova
GSGeorge St. Stoyanov
George St. Stoyanov
IDIvan Donev
Ivan Donev
Circular RNAs (circRNAs) are a group of special endogenous long non-coding RNAs which are highly stable in the circulation, and, thus, more suitable as new biomarkers of colorectal cancer (CRC). The aim of our study was to explore the plasma expression levels of four circRNAs: has_circ_0001445, hsa_circ_0003028, hsa_circ_0007915 and hsa_circ_0008717 in patients with CRC and to evaluate their associations with clinicopathological characteristics and the clinical outcome of the patients. CircRNAs were extracted from patients’ plasma obtained prior to chemotherapy. Their expression levels were measured by qPCR and calculated applying the 2−ΔΔCt method. The levels of all four circRNAs were significantly increased in the plasma of CRC patients. At the optimal cut-off values hsa_circ_0001445 and hsa_circ_0007915 in plasma could significantly distinguish between patients with or without metastatic CRC with 92.56% sensitivity and 42.86% specificity, and with 86.07% sensitivity and 57.14% specificity, respectively. The mean overall survival (OS) of patients with high/intermediate expression of hsa_circ_0001445 was 30 months, significantly higher in comparison with the mean OS of the patients with low expression—20 months (log-rank test, p = 0.034). In multivariate Cox regression analysis, the low levels of hsa_circ_0001445 were also associated with shorter survival (HR = 1.59, 95% CI: 1.02–2.47, p = 0.040). A prognostic significance of hsa_circ_0001445 for patients with metastatic CRC was established.

Verified
Journal Article
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VGVladimir Gerov
Vladimir Gerov
DGDaniela Gerova
Daniela Gerova
IMIlina D. Micheva
Ilina D. Micheva
MNMiglena Nikolova
Miglena Nikolova
GMGalya Mihaylova
Galya Mihaylova
BGBistra Galunska
Bistra Galunska
Dickkopf-1 (DKK-1) and sclerostin are essential Wnt/β-catenin pathway inhibitors, playing an important role in multiple myeloma bone disease (MBD). We aimed to examine the serum DKK-1 and sclerostin variations in newly diagnosed multiple myeloma (NDMM) patients at diagnosis and in the course of therapy, including autologous stem cell transplantation (ASCT). This study included 41 NDMM-patients and 33 controls. MBD was assessed by whole-body low-dose computed tomography. DKK-1 and sclerostin were assayed by commercial ELISA kits. At diagnosis, NDMM-patients revealed significantly higher DKK-1 and sclerostin values (p < 0.0001), showing dependence on disease stage (lowest in ISS-I and highest in ISS-III: p < 0.0012 and p < 0.025, respectively, for both proteins). Bone lesions revealed significant positive correlation with both DKK-1 (p < 0.05) and sclerostin (p < 0.0001). In the course of therapy, significant reduction, more prominent after ASCT, was observed for both parameters in each treatment point compared to the baseline (p < 0.0001). Markedly lower sclerostin (p < 0.01) and DKK-1 (p < 0.05) values were observed in patients with complete and very good partial response compared to those with partial response, stable, or progressive disease. Sclerostin and DKK-1 in NDMM patients reflect the MBD severity and the effect of therapy. Both proteins could represent a novel tool for better disease monitoring and effectiveness of therapy.

24 November 2023 in Cancers
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VGVladimir Gerov
Vladimir Gerov
DGDaniela Gerova
Daniela Gerova
IMIlina D. Micheva
Ilina D. Micheva
MNMiglena Nikolova
Miglena Nikolova
MPMilena Pasheva
Milena Pasheva
BGBistra Galunska
Bistra Galunska
The hallmark of multiple myeloma is myeloma related bone disease. Interactions between myeloma plasma cells (MPCs), stromal cells, and the bone marrow (BM) microenvironment play a critical role in the pathogenesis of MBD. Bone remodeling is severely dysregulated with the prevalence of osteoclast activity. We aimed to assess circulating levels of sRANKL, periostin, and osteopontin as osteoclast activators in NDMM patients at diagnosis and in the course of treatment, correlations with clinical and laboratory data, and to evaluate their potential as additional biomarkers for the assessment of MBD. The current study involved 74 subjects (41 NDMM patients, 33 controls). MBD was assessed by whole-body low-dose computed tomography. sRANKL, periostin, and osteopontin were assayed by commercial ELISA kits. At diagnosis, all tested parameters were significantly higher in NDMM patients compared to the controls (p < 0.0001), correlating with disease stage, MBD grade, and BM infiltration by MPCs. During therapy, the serum levels of all tested proteins decrease, most prominently after autologous stem cell transplantation (p < 0.0001). A significant reduction was established in patients achieving complete and very-good partial response compared to all others (p < 0.05). In conclusion, sRANKL, periostin, and osteopontin reflect MBD severity and could be promising markers for MBD monitoring and the effect of myeloma treatment.

29 March 2026 in Nutrients
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RPRuzha Pancheva
Ruzha Pancheva
MDMaria Ognyanova Dzhogova
Maria Ognyanova Dzhogova
LDLyubomir Dimitrov
Lyubomir Dimitrov
MNMiglena Nikolova
Miglena Nikolova
GMGalya Mihaylova
Galya Mihaylova
Albena MerdzhanovaAlbena Merdzhanova
Albena Merdzhanova
Background: Vitamin B12 deficiency is a recognized but frequently under-integrated cause of global developmental delay (GDD) in infancy and early childhood. Early diagnosis is critical because neurological impairment may be partially or completely reversible with timely treatment. Objective: This narrative review aims to synthesize current evidence on the role of vitamin B12 deficiency in the diagnostic evaluation of GDD, with a focus on clinical phenotype, risk factors, biomarkers, treatment outcomes, and practical integration into contemporary diagnostic algorithms. Methods: A structured, non-systematic search of PubMed/MEDLINE, Embase, and Web of Science was performed to identify clinical studies, case series, reviews, and guideline documents addressing pediatric vitamin B12 deficiency and neurodevelopmental delay. Results: Vitamin B12 deficiency in early childhood is most commonly associated with maternal deficiency and exclusive breastfeeding without adequate supplementation. Evidence from recent clinical and observational studies indicates that vitamin B12 deficiency may present with nonspecific neurological symptoms, including developmental regression, hypotonia, and feeding difficulties. Incorporating vitamin B12 assessment—using serum vitamin B12, holotranscobalamin, methylmalonic acid, and homocysteine—into early diagnostic algorithms for GDD may facilitate timely identification of a treatable cause of neurodevelopmental impairment. The proposed diagnostic framework emphasizes early biochemical evaluation in infants with unexplained developmental delay, thereby supporting prompt treatment during a critical window of neurological reversibility. Conclusions: Targeted assessment of vitamin B12 status in children with GDD, together with evaluation of maternal status, represents a clinically relevant approach to identifying a potentially preventable and treatable cause of neurodevelopmental impairment. Integration of functional biomarkers into diagnostic pathways and the development of pediatric-specific reference standards are key priorities for future research and clinical practice.

Verified
Journal Article
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TSTodorka Sokrateva
Todorka Sokrateva
BRBogdan Roussev
Bogdan Roussev
DVDaniela Vankova
Daniela Vankova
Deyana Georgieva VankovaDeyana Georgieva Vankova
Deyana Georgieva Vankova
DIDiana Ivanova
Diana Ivanova
Milka NasharMilka Nashar
Milka Nashar
Ischemic stroke (IS) is associated with pronounced oxidative stress and lipid peroxidation, which contribute to secondary neuronal damage. This study explored the effects of a six-month intervention with a new formulation containing citicoline, vitamin C, and extracts from green tea and aronia (Cytodeox™) on arachidonic acid (AA) metabolism, lipid peroxidation assessed by total 8-iso-prostaglandin F2α (8-iso-PGF2α), and Sirtuin-1 (SIRT1) expression in healthy controls (n = 43) and patients with IS (n = 53), both with and without comorbidities. AA and 8-iso-PGF2α were quantified in serum using UPLC–MS and ELISA, respectively, and the fold change in SIRT1 expression was assessed in peripheral blood mononuclear cells (PBMCs) by RT-qPCR. In healthy controls, Cytodeox™ significantly lowered AA and 8-iso-PGF2α levels. IS patients showed markedly increased baseline 8-iso-PGF2α, indicating severe oxidative stress. Following supplementation, 8-iso-PGF2α levels increased in patients with comorbidities, particularly diabetes mellitus (DM), whereas an exploratory analysis suggested a decreasing trend in patients without comorbidities. SIRT1 expression was significantly upregulated in IS patients, with the most pronounced increase observed in the DM subgroup, while remaining unchanged in controls. These findings suggest a protective, antioxidant, and membrane stabilising effect of Cytodeox™ under conditions of preserved or moderately impaired redox homeostasis, supporting its potential role as a preventive or early supportive intervention.