Search

As of the 7 th of July 2024, 775,754,322 confirmed cases of COVID-19, including 7,053,902 deaths worldwide, had been reported to the WHO (World Health Organization). Nevertheless, untill the 15 th of July 2024, a total of 13,578,710,228 vaccine doses had been administered, with almost no country spared from COVID-19 attacks. The pathophysiology of this virus is complicated, and several symptoms require a deep understanding of the actual mechanisms. It is unclear why some patients develop severe symptoms while others do not, although literature suggests a role for vitamin D. Vitamin D plays a crucial role in the infection or in ameliorating the severity of symptoms. The mechanism of action of vitamin D and vitamin D deficiency (VDD) is well understood. VDD is associated with increased hospitalization of severely ill patients and increased levels of COVID-19-caused mortality. Recent studies suggest that vitamin D levels and genetic variations in the vitamin D receptor (VDR) gene significantly impact the severity and outcomes of COVID-19, especially in the infections caused by Delta and Omicron variants. Furthermore, VDD causes immune system dysregulation upon infection with SARS-CoV-2, indicating that vitamin D sufficiency is crucial in fighting against COVID-19 infection. The therapeutic effect of vitamin D raises interest in its potential role as a prophylactic and treatment adjunct. We evaluate the immunomodulatory effects of vitamin D and its ability to enhance the efficacy of new antiviral drugs like molnupiravir and paxlovid against SARS-CoV-2. This review discusses the role of vitamin D sufficiency and VDD in COVID-19 initiation and progression, emphasizing the molecular mechanisms by which vitamin D exerts its actions as a proactive step for the next pandemic. However, there is still no clear evidence of vitamin D's impact on prevention and treatment, leading to contradictory findings. Therefore, large-scale randomized trials are required to reach a definitive conclusion. A bibliometric analysis of publications related to vitamin D, immunity, and COVID-19 revealed a significant increase in research activity in this area, particularly in 2020-2024, underscoring the growing recognition of vitamin D's potential role in the context of the pandemic., (© 2024. The Author(s).)

Objective and Design: Ghrelin has a key role in modulating energy metabolism and weight gain. The present study aimed at studying the potential role of ghrelin in the development and/or exacerbation of organ damage in a mouse model of diet-induced obesity., Objective and Design: Adult mice were fed one of two diets for 20 weeks: standard high carbohydrate (HC) or high-fat high-sugar (HFHS). Starting week 17, the animals were given regular intraperitoneal ghrelin (160 µg/kg) or saline injections Abdominal fat, serum creatinine, and glucose levels, as well as kidney, liver and heart weight and pathology were assessed., Results: Ghrelin-injected mice showed significant organ damage, which was more exacerbated in HFHS-fed animals. While the HFHS diet was associated with significant liver damage, ghrelin administration did not reverse it. Interestingly, ghrelin administration induced moderate kidney damage and significantly affected the heart by increasing perivascular and myocardium fibrosis, steatosis as well as inflammation. Moreover, serum creatinine levels were higher in the animal group injected with ghrelin., Conclusion: Ghrelin administration was associated with increased functional and structural organ damage, regardless of diet. The present study provides novel evidence of multi-organ physiologic alterations secondary to ghrelin administration.

Objective and Design: The aim of this study is to elucidate TGF-β1 signaling pathways involved in COX-2 protein induction and modulation of TAU protein phosphorylation in cultured podocytes., Materials, Treatment and Methods: In vitro cultured immortalized podocytes were stimulated with TGF-β1 in presence and absence of pharmacologic inhibitors for various signaling pathways and phosphatases. Then, COX-2 protein expression, as well as P38MAPK, AKT and TAU phosphorylation levels were evaluated by western blot analysis., Results: TGF-β1 induction of COX-2 protein levels was completely blocked by pharmacologic inhibitors of phosphatases, P38 MAPK, or NF-қB pathways. Time course experiments showed that TGF-β1 activated p38 MAPK after 5 min of stimulation. Interestingly, podocyte co-incubated with TGF-β1, high glucose and/or PGE2 showed strong increase in p38 MAPK and AKT phosphorylation as well as COX- 2 protein expression levels. Levels of phosphorylated AKT were further reduced and levels of phosphorylated p38 were increased when PGE2 was added to the culture media. Interestingly, selective phosphatases inhibitors completely abrogated PGE2-induced P38 MAPK and TAU phosphorylation. Also, inhibition of phosphatases reversed TGF-β1-induced COX-2 protein expression either alone or when incubated with high glucose or PGE2., Conclusion: These data suggest TGF-β1 mediates its effect in podocyte through novel signaling mechanisms including phosphatases and TAU protein phosphorylation.