Recent studies showed that a low 25-hydroxyvitamin D (25(OH)D) level was associated with a higher risk of morbidity and severe course of COVID-19. Our study aimed to evaluate the effects of cholecalciferol supplementation on the clinical features and inflammatory markers in patients with COVID-19. A serum 25(OH)D level was determined in 311 COVID-19 patients. Among them, 129 patients were then randomized into two groups with similar concomitant medication. Group I (n = 56) received a bolus of cholecalciferol at a dose of 50,000 IU on the first and the eighth days of hospitalization. Patients from Group II (n = 54) did not receive the supplementation. We found significant differences between groups with the preferential increase in serum 25(OH)D level and Δ 25(OH)D in Group I on the ninth day of hospitalization (p < 0.001). The serum 25(OH)D level on the ninth day was negatively associated with the number of bed days (r = −0.23, p = 0.006); we did not observe other clinical benefits in patients receiving an oral bolus of cholecalciferol. Moreover, in Group I, neutrophil and lymphocyte counts were significantly higher (p = 0.04; p = 0.02), while the C-reactive protein level was significantly lower on the ninth day of hospitalization (p = 0.02). Patients with supplementation of 100,000 IU of cholecalciferol, compared to those without supplementation, showed a decrease in the frequencies of CD38++CD27 transitional and CD27−CD38+ mature naive B cells (p = 0.006 and p = 0.02) and an increase in the level of CD27−CD38− DN B cells (p = 0.02). Thus, the rise in serum 25(OH)D level caused by vitamin D supplementation in vitamin D insufficient and deficient patients may positively affect immune status and hence the course of COVID-19.

Background: SGLT-2 inhibitors (SGLT-2i) and GLP-1 receptor agonists (GLP-1RA) have demonstrated nephro- and cardioprotective effects, but their neuroprotective properties, especially concerning stroke severity, and mechanisms are not unambiguous. We aimed to study the influence of SGLT-2i with different selectivity and GLP-1RA on brain damage volume and neurological status in non-diabetic and diabetic rats and to investigate the underlying mechanisms. Methods: Non-diabetic Wistar rats were divided into five groups (n = 10 each) and received empagliflozin, canagliflozin, or dulaglutide as study drugs and metformin as comparison drug. Control animals were administered 0.9% NaCl for 7 days before stroke. At 48 h after stroke, we assessed neurological deficit, neuronal and astroglial damage markers, and brain damage volume. We also modeled type 2 DM in Wistar rats using the high-fat diet+nicotinamide/streptozotocin method and established similar treatment groups. After 8 weeks, rats were subjected to stroke with further neurological deficit, neuroglial damage markers, and brain necrosis volume measurement. Results: In non-diabetic rats, all the drugs showed an infarct-limiting effect; SGLT-2i and dulaglutide were more effective than metformin. DULA improved neurological status compared with MET and SGLT-2i treatment. All the drugs decreased neurofilament light chains (NLCs) level and neuronal damage markers, but none of them decreased the glial damage marker S100BB. In DM, similarly, all the drugs had infarct-limiting effects. Neurological deficit was most pronounced in the untreated diabetic rats and was reduced by all study drugs. All the drugs reduced NLC level; dulaglutide and empagliflozin, but not canagliflozin, also decreased S100BB. None of the drugs affected neuron-specific enolase. Conclusions: SGLT-2i and GLP-1RA are neuroprotective in experimental stroke. GLP-1RA might be more effective than SGLT-2i as in non-diabetic conditions it influences both brain damage volume and neurological status. All study drugs decrease neuronal damage, while GLP-1RA and highly selective SGLT-2i EMPA, but not low-selective CANA, also have an impact on neuroglia in diabetic conditions.

COVID-19, caused by SARS-CoV-2, triggers a complex immune response, with T regulatory cells (Tregs) playing a crucial role in maintaining immune homeostasis and preventing excessive inflammation. The current study investigates the function of T regulatory cells during COVID-19 infection and the subsequent recovery period, emphasizing their impact on immune regulation and inflammation control. We conducted a comprehensive analysis of Treg subpopulations in peripheral blood samples from COVID-19 patients at different stages: acute infection, early convalescence, and long-term recovery. Flow cytometry was employed to quantify Tregs including “naïve”, central memory (CM), effector memory (EM), and terminally differentiated CD45RA⁺ effector cells (TEMRA). Additionally, the functional state of the Tregs was assessed by the expression of purinergic signaling molecules (CD39, CD73). Cytokine profiles were assessed through multiplex analysis. Our findings indicate a significant decrease in the number of Tregs during the acute phase of COVID-19, which correlates with heightened inflammatory markers and increased disease severity. Specifically, we found a decrease in the relative numbers of “naïve” and an increase in EM Tregs, as well as a decrease in the absolute numbers of “naïve” and CM Tregs. During the early convalescent period, the absolute counts of all Treg populations tended to increase, accompanied by a reduction in pro-inflammatory cytokines. Despite this, one year after recovery, the decreased subpopulations of regulatory T cells had not yet reached the levels observed in healthy donors. Finally, we observed the re-establishment of CD39 expression in all Treg subsets; however, there was no change in CD73 expression among Tregs. Understanding these immunological changes across different T regulatory subsets and adenosine signaling pathways offers important insights into the disease’s pathogenesis and provides a broader view of immune system dynamics during recovery.

Recent studies have demonstrated the relationship between vitamin D deficiency, infection severity and mortality from COVID-19. This study aimed to analyze the vitamin D metabolites and cytokine expression levels of COVID-19 patients who were hospitalized with bolus cholecalciferol supplementation. Materials and methods: This study represents the next stage of the open-label randomized pilot conducted by the Almazov National Medical Research Centre. A total of 44 hospitalized patients, comparable in demographic, clinical, laboratory and instrumental baseline characteristics, with moderate/severe COVID-19 were included. All patients had similar doses of concomitant corticosteroid therapy. Twenty-two patients received 50,000 IU cholecalciferol on the first and eighth days of hospitalization. The serum 25(OH)D, 1,25(OH)2D and 28 plasma cytokines were estimated for each group initially and on the ninth day of hospitalization. Results: Initially, there were no differences in the 1,25(OH)2D and cytokine levels in patients with vitamin D deficiency and normal 25(OH)D. Bolus cholecalciferol therapy at a total dose of 100,000 IU led to an increase in 25(OH)D levels in hospitalized patients with COVID-19, while the levels of the active metabolite (1,25(OH)2D) did not show significant differences between the groups or in its increased level over time, regardless of cholecalciferol supplementation. Furthermore, cholecalciferol supplementation at a total dose of 100,000 IU did not affect the majority of the cytokines estimated on the ninth day of hospitalization, except for the pro-inflammatory marker IL-1b, the concentration of which was lower in the group of patients without vitamin D supplementation. Conclusions: The 25(OH)D level was positively associated with an anti-inflammatory immune response, but cholecalciferol supplementation at a total dose of 100,000 IU did not affect the active-form vitamin D or cytokine expression levels. This fact may be explained by the impact of corticosteroid therapy, and it requires further investigation in a post-COVID-19 context.

Thyroid cancer remains the most common malignancy of the endocrine system worldwide. The indicators of its morbidity and mortality rates have been increasing rapidly over the last decades. Most cases of differentiated thyroid cancer (follicular and papillary histotypes) are clinically manifested by nodular goiter frequently combined with uncertain results of cytological diagnosis (categories III and IV according to the Bethesda (Bethesda System for Reporting Thyroid Cytopathology) classification). All of that makes it difficult to choose a proper tactic for patient treatment. It is known that the development, progression, invasion, and metastasis of cancer cells are regulated by a variety of molecular mechanisms. This review describes several molecular aspects of thyroid nodules oncogenesis, as well as its most promising diagnostic tumor markers. Following molecular pathways are described in particular: gene mutations, protein tumor markers, and epigenetic effects of micro-RNA, histones, as well as DNA methylation. The study of the pathogenesis of this disease has a prognostic value and contributes to the search for effective therapeutic and diagnostic methods and their improvement. That is why we also reviewed modern test panels aimed at preoperative differential diagnosis of thyroid nodules. Summarizing the results of world research on this topic allows us not only to expand the understanding of the fundamental processes of oncogenesis, but also to outline promising areas for future experimental research projects. All of that together will contribute to developing new prognostic, diagnostic and therapeutic technologies, and as a result, will improve the quality of medical care for patients with thyroid cancer.

BACKGROUND. Glucose metabolism disorders (GMD) were detected both in acute and in post-COVID, however, its pathogenic aspects remain unclear.AIM. To analyze the occurrence of GMD in post-COVID patients who have had moderate and severe COVID-19 without previously known GMD disorders, and evaluate expression of SARS-CoV-2 proteins and its entry factors in pancreas in acute COVID-19.METHODS. Among 187 hospitalized patients with confirmed COVID-19 141 patients without previously diagnosed GMD underwent follow-up post-COVID visits. The examination for all patients included anthropometric measurement with calculation of BMI, level of HbA1c and fasting plasma glucose, for 106 patients level of insulin and HOMA-IR index was analyzed. For histological examination, pancreas fragments of 20 patients with fatal outcome were selected. Immunohistochemical study was performed with antibodies to SARS-CoV-2, ACE2, DPP4, as well as double-labeled immunofluorescence microscopy (insulin-SARS-CoV-2, insulin-ACE2, insulin-DPP4).RESULTS. Among 141 patients in post-COVID period, 9 (6.3%) had HbA1c or fasting plasma glucose levels that met criteria for diabetes mellitus, 38 (26.9%) — exceeded normal values (WHO), and 84 (59.6%) had GMD according to criteria of the ADA. In post-COVID, patients with GMD had a higher BMI and HOMA-IR index (p=0.001) compared to patients with normal glycemic levels. Only 40.4% of people had HOMA-IR index above 2.7. Patients with GMD had higher level of CRP (p=0.007) and a maximum glucose level (p=0.019) in the acute period. Positive relationship was found between BMI and HOMA index both in acute (p<0.001; r=0.389) and post-COVID (p<0.001; r=0.412) periods, as well as the level of HbA1c in acute period (p=0.019, r=0.202) and in post-COVID (p=0.004, r=0.242).Histological and immunohistochemical studies showed the expression of SARS-CoV-2 proteins in 1.85% [0–15.4] and 11.1% [5.3–14.8] cells of the Langerhans islets in patients who died on the second and third waves, respectively. The expression of ACE2 and DPP4 in the islets of Langerhans did not exceed 0.4% [0–1.7] and 0.5% [0–0.8] of cells, respectively. Double-labeled immunofluorescence microscopy showed co-localization of SARS-CoV-2, ACE2, DPP4 with insulin.CONCLUSION. Post-COVID Glucose metabolism disorders may be explained by direct cytotoxic effect of SARS-COV-2, increased glucose toxicity and insulin resistance because of the acute infection and its complex therapy.