With the rapid progress of genetic engineering and gene therapy, World Anti-Doping Agency has alerted to gene doping and prohibited its use in sports. However, there is no standard method available yet for detection of transgenes delivered by recombinant adenoviral (rAdV) vectors. Here we aimed to develop a detection method for transgenes delivered by rAdV vectors in a mouse model that mimics gene doping. rAdV vectors containing mCherry gene was delivered in mice through intravenous injection or local muscular injection. After five days, stool and whole blood samples were collected, and total DNA was extracted. As additional experiments, whole blood was also collected from mouse tail tip until 15 days from injection of the rAdv vector. Transgene fragments from different DNA samples were analyzed using semi-quantitative PCR (sqPCR), quantitative PCR (qPCR), and droplet digital PCR (ddPCR). In the results, transgene fragments could directly be detected from blood cell fraction-DNA, plasma-cell free DNA and stool-DNA by qPCR and ddPCR, depending on specimen type and injection methods. We observed that a combination of blood cell fraction-DNA and ddPCR was more sensitive than other combinations used in this model. These results could accelerate the development of detection methods for gene doping.

The World Anti-Doping Agency (WADA) has prohibited gene doping in the context of progress in gene therapy. In addition, there is a risk of the EPO gene being applied in gene doping among athletes. Along with this, development of a gene-doping test has been underway in worldwide. Here, we had two purposes: to develop a robust gene doping mouse model using the human EPO gene (hEPO) transferred using recombinant adenovirus (rAdV) as a vector and to develop a detection method to prove gene doping using this model. The rAdV including the hEPO gene were injected intravenously to transfer the gene to the liver. After injection, the mice developed significantly increased red blood cell counts in whole blood and increased gene expressions of hematopoietic markers in the spleen, indicating successful development of the gene doping model. Next, we detected direct and indirect proof of gene doping in whole blood DNA and RNA using qPCR assay and RNA sequencing. Proof was detected in one drop of whole blood DNA and RNA over a long period; furthermore, the overall RNA expression profiles significantly changed. Therefore, we have advanced detection of hEPO gene doping in humans.

Molecular therapies exploiting mRNA vectors embody enormous potential, as evidenced by the utility of this technology for the context of the COVID-19 pandemic. None-the-less, broad implementation of these promising strategies has been restricted by the limited repertoires of delivery vehicles capable of mRNA transport. On this basis, we explored a strategy based on exploiting the well characterized entry biology of adenovirus. To this end, we studied an adenovirus-polylysine (AdpL) that embodied “piggyback” transport of the mRNA on the capsid exterior of adenovirus. We hypothesized that the efficient steps of Ad binding, receptor-mediated entry, and capsid-mediated endosome escape could provide an effective pathway for transport of mRNA to the cellular cytosol for transgene expression. Our studies confirmed that AdpL could mediate effective gene transfer of mRNA vectors in vitro and in vivo. Facets of this method may offer key utilities to feasibilize the promise of mRNA-based therapeutics.

The immunization of healthcare workers in the early stages of the rollout of COVID-19 vaccines was prioritized in order to ensure uninterrupted medical care provision. At the same time the increasing number of available COVID-19 vaccines may trigger hesitancy towards the decision to get vaccinated. Thus, accumulating reliable information on the adverse events following immunization may educate and urge the general population to receive a COVID-19 vaccine. The present study aimed to evaluate the adverse events (AEs) following immunization with any of the available COVID-19 vaccine among Bulgarian healthcare workers (HCWs). A cross-sectional study among HCWs in Plovdiv, Bulgaria was conducted in the period March – September 2021. Through a semi-structured online questionnaire, the participants reported the adverse events following the administration of the first and second dose of a COVID-19 vaccine. A total of 253 respondents, vaccinated with one of the available vaccines against COVID-19 took part in the study. Of them 71.9% were females, and 75.9% received mRNA-based vaccines, while 24.1% received a viral-vector based vaccine. Overall 91.6% and 82.6% of all participants reported at least one local AE after the first and second dose of a COVID-19 vaccine. The share of respondents reporting at least one systemic AE after the first and second dose of a COVID-19 vaccine was 59.7% and 62.4% respectively. The most common local AE was pain at the injection spot (84.0%), while the most common systemic AEs were fatigue (54.9%), chills (43.2%), and headache (41.7%). The mRNA-based vaccines versions seem to cause higher prevalence of local AEs, while the vector-based vaccines were linked with increased prevalence of systemic AEs. Female HCWs and the younger age group were associated with an increased risk of adverse events generally. Our results added more evidence that mRNA-based and viral-vector based vaccines are generally safe. The reported adverse events were mild, although they occurred in a high share of the respondents. No serious AEs attributable to the vaccines were reported.

Premature ovarian insufficiency (POI) is a highly prevalent disorder, characterized by the development of menopause before age of 40. Most cases are idiopathic; however, in some women the cause of this condition (e.g. anticancer treatment, genetic disorders, and enzymatic defects) may be identified. Although hormone replacement therapy, the principal therapeutic approach for POI, helps to alleviate the related symptoms, this does not effectively solve the issue of fertility. Assisted reproductive techniques also lack efficacy in these women. Thus, the effective approach to manage the patients with POI is highly warranted. Several mechanisms, associated with POI, have been identified, including lack of FSH receptor functioning, alterations in the apoptosis control, mutations in Sal-like 4 genes, thymulin or basonuclin-1 deficiency etc. The above-mentioned may be good targets for gene therapy in order to correct defects, leading to POI. The goal of this review is to summarize the current experience on the POI studies, that employed gene therapy, and to discuss the possible future directions in this field.