Mesenchymal stem cells (MSCs) have remarkable immunomodulatory properties, low immunogenicity, and paracrine properties as well as the ability to differentiate into multiple cell lines. These properties make them potential candidates for clinical applications in the treatment of neurodegenerative, cardiovascular, and lung diseases, which may be occupational diseases. Preclinical studies using experimental animal models have demonstrated regenerative properties of MSCs in diseases such as silicosis and occupational asthma. Currently, treatment of the novel disease COVID-19 could be enhanced by using MSC therapies. This disease affects many professional groups with great intensity and its consequences might be considered as an occupational disease. It is a significant public health problem and a therapeutic challenge. Despite the development of vaccines against COVID-19, there is growing concern about the emergence of new mutations of the SARS-CoV-2 virus in addition to the known alpha, beta, gamma, and delta variants. There is still no effective COVID-19 treatment and the existing ones only play a supporting role. MSCs offer treatment possibilities as an alternative or complementary therapy. The clinical trials to date using MSCs in patients with COVID-19 give hope for the safe and effective use of this stem cell population.
Objectives Gonadoliberin (GnRH) analogs may be expected to indirectly modify growth hormone (GH) total concentration and its 24-h secretion profile. As a consequence, changes in the levels of GH may modify the mechanism of sexdependent cytochromes P450 (CYP450) synthesis, including the expression of transcriptional factors. The aim of the study has been to evaluate the effect of long-term administration of a low dose of GnRH analogs on hepatic expression of CYP2C and CYP3A isoforms, and the transcription factors: pregnane X receptor (PXR), hepatocyte nuclear factor 4α (HNF4α), HNF6 and signal transducers and activators of transcription 5b (STAT5b). Material and Methods The study was carried out on adult female Sprague-Dawley rats during a 3-month treatment with dalarelin (GnRH agonist) and cetrorelix (GnRH antagonist), at a daily intraperitoneal injection (i.p.) dose of 6 μg/kg body weight/day, and 1, 2, and 4 weeks after treatment discontinuation. The concentrations of ovarian hormones and GH in the blood serum were determined by radioimmunoassay and enzyme-linked immunosorbent assay (ELISA) method, respectively. Then, the expression of hepatic CYP450s (reverse transcription polymerase chain reaction – RT-PCR, Western blot and immunohistochemistry) and transcription factors (RT-PCR) was evaluated. Results We have found that cetrorelix induces changes in the circadian pattern of GH secretion and enhances GH blood concentrations. These changes may cause increased expression of both, female-specific CYP450s (especially CYP3A9), and HNF4α/HNF6 transcription factors. Decrease in GH blood concentrations, resulting from the effect of dalarelin, may promote inhibition of female-specific CYP2C12 and CYP3A9 isoforms as well as STAT5b transcription factor. Slight changes in sex-independent CYP3A1 protein expression caused by GnRH analogs were also observed. Conclusions In adult female rats, HNF4α/HNF6 and STAT5b seem to be crucial for the regulation of GnRH antagonist/GH- and GnRH agonist/GH-dependent pattern of CYP450 expression, respectively.
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