Bozhidar Vergov

Dr. Bozhidar Vergov

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

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

Representative Publications

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Verified
Journal Article
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YSYordan Sbirkov
Yordan Sbirkov
BVBozhidar Vergov
Bozhidar Vergov
Nikolay MehterovNikolay Mehterov
Nikolay Mehterov
VSVictoria Sarafian
Victoria Sarafian
Refractory disease and relapse remain the main causes of cancer therapy failure. Refined risk stratification, treatment regimens and improved early diagnosis and detection of minimal residual disease have increased cure rates in malignancies like childhood acute lymphoblastic leukaemia (ALL) to 90%. Nevertheless, overall survival in the context of drug resistance remains poor. The regulatory role of micro RNAs (miRNAs) in cell differentiation, homeostasis and tumorigenesis has been under extensive investigation in different cancers. There is accumulating data demonstrating the significance of miRNAs for therapy outcomes in lymphoid malignancies and some direct demonstrations of the interplay between these small molecules and drug response. Here, we summarise miRNAs’ impact on chemotherapy resistance in adult and paediatric ALL and chronic lymphocytic leukaemia (CLL). The main focus of this review is on the modulation of particular signaling pathways like PI3K-AKT, transcription factors such as NF-κB, and apoptotic mediators, all of which are bona fide and pivotal elements orchestrating the survival of malignant lymphocytic cells. Finally, we discuss the attractive strategy of using mimics, antimiRs and other molecular approaches pointing at miRNAs as promising therapeutic targets. Such novel strategies to circumvent ALL and CLL resistance networks may potentially improve patients’ responses and survival rates.

Verified
Journal Article
Open access
PDF file
YSYordan Sbirkov
Yordan Sbirkov
BVBozhidar Vergov
Bozhidar Vergov
VDVasil Dzharov
Vasil Dzharov
TSTino Schenk
Tino Schenk
KPKevin Petrie
Kevin Petrie
VSVictoria Sarafian
Victoria Sarafian
The prognosis for patients with relapsed childhood acute lymphoblastic leukaemia (cALL) remains poor. The main reason for treatment failure is drug resistance, most commonly to glucocorticoids (GCs). The molecular differences between prednisolone-sensitive and -resistant lymphoblasts are not well-studied, thereby precluding the development of novel and targeted therapies. Therefore, the aim of this work was to elucidate at least some aspects of the molecular differences between matched pairs of GC-sensitive and -resistant cell lines. To address this, we carried out an integrated transcriptomic and metabolomic analysis, which revealed that lack of response to prednisolone may be underpinned by alterations in oxidative phosphorylation, glycolysis, amino acid, pyruvate and nucleotide biosynthesis, as well as activation of mTORC1 and MYC signalling, which are also known to control cell metabolism. In an attempt to explore the potential therapeutic effect of inhibiting one of the hits from our analysis, we targeted the glutamine-glutamate-α-ketoglutarate axis by three different strategies, all of which impaired mitochondrial respiration and ATP production and induced apoptosis. Thereby, we report that prednisolone resistance may be accompanied by considerable rewiring of transcriptional and biosynthesis programs. Among other druggable targets that were identified in this study, inhibition of glutamine metabolism presents a potential therapeutic approach in GC-sensitive, but more importantly, in GC-resistant cALL cells. Lastly, these findings may be clinically relevant in the context of relapse—in publicly available datasets, we found gene expression patterns suggesting that in vivo drug resistance is characterised by similar metabolic dysregulation to what we found in our in vitro model.

11 January 2024 in Biology Methods and Protocols
Verified
Journal Article
Open access
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BVBozhidar Vergov
Bozhidar Vergov
YSYordan Sbirkov
Yordan Sbirkov
DMDanail Minchev
Danail Minchev
TTTatyana Todorova
Tatyana Todorova
ABAlexandra Baldzhieva
Alexandra Baldzhieva
VSVictoria Sarafian
Victoria Sarafian
Monitoring the blood serum activity of L-asparaginase in children with acute lymphoblastic leukaemia (ALL) has been highly recommended to detect enzyme inactivation that can cause relapse and to avoid unwanted toxicity. Nevertheless, perhaps at least partially due to the lack of clinically approved commercially available kits or standardized and independently reproduced and validated in-house protocols, laboratory assay-based determination of the optimal doses of L-asparaginase is not carried out routinely. In this study, we adapted previously published protocols for two plate reader-based colorimetric methods, indooxine and Nessler, to measure asparaginase activity. Mock samples with dilutions of the enzyme for initial optimization steps, and patient samples were used as a proof of principle and to compare the two protocols. For the first time the indooxine and the Nessler methods are adapted for a plate reader and L-asparaginase serum activity levels are compared by both protocols. Passing–Bablok and Bland–Altman’s statistical analyses found very little difference, strong correlation (r = 0.852), and bias of only 6% between the data from the two methods when used for fresh patient samples. Furthermore, we demonstrate that the Nessler method could also be applied for frozen sera as the results, compared to fresh samples, showed little difference, strong correlation (r = 0.817), and small bias (9%). We successfully adapted and validated two methods for measuring L-asparaginase activity in cALL and provided the most detailed description to date on how to reproduce and implement them in other clinical laboratories.

19 July 2023 in Healthcare
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Journal Article
Open access
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BVBozhidar Vergov
Bozhidar Vergov
AAAndreana Angelova
Andreana Angelova
ABAlexandra Baldzhieva
Alexandra Baldzhieva
YKYordan Kalchev
Yordan Kalchev
GTGeorgi Tsochev
Georgi Tsochev
MMMarianna Atanassova Murdjeva
Marianna Atanassova Murdjeva
Improvements in medical care have turned severe diseases into chronic conditions, but often their treatment and the use of medical devices are related to specific complications. Here, we present a clinical case of a long-term dialysis patient who was infected with a rare opportunistic infectious agent—Gordonia sputi. In recent years, the incidence of Gordonia spp. infections in immunocompromised patients with central venous catheters (CVC) has appeared to rise. The isolation and identification of Gordonia spp. are challenging and require modern techniques. In addition, the treatment is usually persistent and often results in CVC extraction, which is associated with further risk and costs for the patient. We also studied the alterations in the immune status of the patient caused by long-term renal replacement therapy and persistent hepatitis C virus infection. Antibiotic therapy and immunostimulation with Inosine pranobex lead to successful eradication of the infection without the need for CVC replacement.

22 September 2025 in Preprints.org
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Preprint
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BVBozhidar Vergov
Bozhidar Vergov
YSYordan Sbirkov
Yordan Sbirkov
KDKostadin Dimitrov
Kostadin Dimitrov
VZVioleta Zheleva
Violeta Zheleva
The incidence of kidney diseases has been increasing in the last decade due to extended lifespan, which is often related to polymorbidity. Chronic kidney disease (CKD) and acute kidney injury (AKI) are associated with high morbidity and mortality, elevated costs for renal replacement therapy and heavy psychosomatic burden. At the same time, therapeutic options are limited to prophylactic and renoprotective medications and measurements, and they often cannot restore the impaired kidney function. With the development of cellular therapies new perspectives arise on the horizon whit promising potential- mesenchymal stem cells (MSCs) and induced pluripotent cells (iPSCs). Here we review the current possibility of both cell types in the field of nephrology and assess their cost implication.

29 June 2023 in Preprints.org
Verified
Preprint
Open access
PDF file
BVBozhidar Vergov
Bozhidar Vergov
AAAndreana Angelova
Andreana Angelova
ABAlexandra Baldzhieva
Alexandra Baldzhieva
YKYordan Kalchev
Yordan Kalchev
GTGeorgi Tsochev
Georgi Tsochev
MMMarianna Atanassova Murdjeva
Marianna Atanassova Murdjeva
Improvement in medical care has turned severe diseases into chronic conditions, but often their treatment and use of medical devices are related to specific complications. Here we present a clinical case of a long-term dialysis patient, who is infected with a rare opportunistic infectious agent – Gordonia sputi. In recent years the incidence of Gordonia spp. infections in immunocompromised patients with central venous catheters (CVC) appear to rise. Their isolation and identification are challenging and require modern techniques. In addition, the treatment is usually persistent and often results in CVC extraction, which is associated with further risk and costs for the patient. We also studied the alternations in the immune status of the patient caused by long-term renal replacement therapy and persistent HCV infection. Antibiotic therapy and immunostimulation with Inosine pranobex lead to successful eradication of the infection without the need for CVC replacement.