Publication trends of research on COVID-19 and host immune response: A bibliometric analysis.

Introduction: As the first bibliometric analysis of COVID-19 and immune responses, this study will provide a comprehensive overview of the latest research advances. We attempt to summarize the scientific productivity and cooperation across countries and institutions using the bibliometric methodology. Meanwhile, using clustering analysis of keywords, we revealed the evolution of research hotspots and predicted future research focuses, thereby providing valuable information for the follow-up studies. Methods: We selected publications on COVID-19 and immune response using our pre-designed search strategy. Web of Science was applied to screen the eligible publications for subsequent bibliometric analyses. GraphPad Prism 8.0, VOSviewer, and CiteSpace were applied to analyze the research trends and compared the contributions of countries, authors, institutions, and journals to the global publications in this field. Results: We identified 2,200 publications on COVID-19 and immune response published between December 1, 2019, and April 25, 2022, with a total of 3,154 citations. The United States (611), China (353), and Germany (209) ranked the top three in terms of the number of publications, accounting for 53.3% of the total articles. Among the top 15 institutions publishing articles in this area, four were from France, four were from the United States, and three were from China. The journal Frontiers in Immunology published the most articles (178) related to COVID-19 and immune response. Alessandro Sette (31 publications) from the United States were the most productive and influential scholar in this field, whose publications with the most citation frequency (3,633). Furthermore, the development and evaluation of vaccines might become a hotspot in relevant scope. Conclusions: The United States makes the most indispensable contribution in this field in terms of publication numbers, total citations, and H-index. Although publications from China also take the lead regarding quality and quantity, their international cooperation and preclinical research need to be further strengthened. Regarding the citation frequency and the total number of published articles, the latest research progress might be tracked in the top-ranking journals in this field. By analyzing the chronological order of the appearance of retrieved keywords, we speculated that vaccine-related research might be the novel focus in this field.

Global Research Status of Multiple Organ Dysfunction Syndrome During 2001-2021: A 20-Year Bibliometric Analysis.

Background: Multiple Organ Dysfunction Syndrome (MODS) is a major cause of high morbidity and mortality among patients in intensive care units (ICU). Although numerous basic and clinical researches on MODS have been conducted, there is still a long way to go to prevent patients from entering this stage. To our knowledge, no bibliometric analyses of MODS have been reported, this study, therefore, was conducted to reveal MODS research status and trends during 2001-2021. Methods: All relevant literature covering MODS during 2001-2021 were extracted from Web of Science. An online analysis platform of literature metrology was used to analyze the publication trends. VOSviewer software was used to collect and analyze the keywords and research hotspots related to MODS. Results: As of July 31, 2021, a total of 994 MODS-related articles from 2001 to 2021 were identified. The United States accounted for the largest number of publications (31.1%), followed by China and Germany, with 186 and 75 publications, respectively. Among all the institutions, the University of Pittsburgh published the most papers related to MODS (21). Critical Care Medicine published the most papers in this field (106). Professor Moore EE, who had the most citation frequency (1847), made great achievements in MODS research. Moreover, analysis of the keywords identified three MODS research hotspot clusters: "mechanism-related research," "clinical research," and "diagnostic research." Conclusions: The United States maintained a top position worldwide and made the most outstanding contribution in the MODS field. In terms of publication, China was next only to the United States, but there was a disproportion between the quantity of publications and citation frequency. The institution University of Pittsburgh and journal Critical Care Medicine represent the highest level of research in this field. During the 20 years from 2001 to 2021, basic MODS research has been in-depth yet progressed relatively slowly recently, but the outbreak of COVID-19 has to some extent set off an upsurge of clinical research in MODS field.

Melatonin rescues glucocorticoid-induced inhibition of osteoblast differentiation in MC3T3-E1 cells via the PI3K/AKT and BMP/Smad signalling pathways.

AIMS: High-dose glucocorticoid (GC) administration causes osteoporosis. Many previous studies from our group and other groups have shown that melatonin participates in the regulation of osteoblast proliferation and differentiation, especially low concentrations of melatonin, which enhance osteoblast osteogenesis. However, the role of melatonin in glucocorticoid-induced osteoblast differentiation remains unknown. MATERIALS AND METHODS: An examination of the expression of osteoblast differentiation markers (ALP, OCN, COLL-1), as well as alkaline phosphatase staining and alkaline phosphatase enzymatic activity assay to measure osteoblast differentiation and quantifying Alizarin red S staining to measure mineralization, were performed to determine the effects of dexamethasone (Dex) and melatonin on the differentiation of MC3T3-E1 cells. We used immunofluorescence staining to detect the expression of Runx2 in melatonin-treated MC3T3-E1 cells. The expression of mRNA was determined by qRT-PCR, and protein levels were measured by western blotting. KEY FINDINGS: In the present study, we found that 100 µM Dex significantly reduced osteoblast differentiation and mineralization in MC3T3-E1 cells and that 1 µM melatonin attenuated these inhibitory effects. We found that only inhibition of PI3K/AKT (MK2206) and BMP/Smad (LDN193189) signalling abolished melatonin-induced differentiation and mineralization. Meanwhile, MK2206 decreased the expression of P-AKT and P-Smad1/5/9 and LDN193189 decreased the expression of P-Smad1/5/9 but had no obvious effect on P-AKT expression in melatonin-treated and Dex-induced MC3T3-E1 cells. SIGNIFICANCE: These findings suggest that melatonin rescues Dex-induced inhibition of osteoblast differentiation in MC3T3-E1 cells via the PI3K/AKT and BMP/Smad signalling pathways and that PI3K/AKT signalling may be the upstream signal of BMP/Smad signalling.

Melatonin induces mitochondrial apoptosis in osteoblasts by regulating the STIM1/cytosolic calcium elevation/ERK pathway.

AIMS: Idiopathic scoliosis is a common deformity of the spine that has an especially high incidence rate in adolescents. Some studies have demonstrated a close relationship between idiopathic scoliosis and melatonin deficiency. Our team's previous research showed that melatonin can inhibit the proliferation of osteoblasts, but the mechanism remains unclear. This study aimed to determine the mechanism by which melatonin inhibits the proliferation of osteoblasts. MAIN METHODS: Cell viability experiment, DNA fragment detection and alkaline phosphatase (ALP) activity assays were performed to determine the effects of melatonin on the proliferation, apoptosis and differentiation of osteoblasts. We used immunofluorescence to detect the expression of STIM1 in melatonin-treated osteoblasts. STIM1 interference was achieved using a specific siRNA, and a TRPC inhibitor was used to block the influx of Ca2+. The mRNA expression was determined by RT-qPCR, and protein levels were measured by Western blot. KEY FINDINGS: In this study, we found that melatonin inhibited the proliferation, differentiation and apoptosis of osteoblasts in a concentration-dependent manner. Additional studies showed that melatonin elevated cytosolic calcium levels by upregulation of STIM1, leading to osteoblast apoptosis via the mitochondrial pathway. Finally, we demonstrated that the STIM1-mediated increase in cytosolic calcium levels induced apoptosis through the ERK pathway. SIGNIFICANCE: Melatonin induces mitochondrial apoptosis in osteoblasts by regulating the STIM1/cytosolic calcium elevation/ERK pathway. These basic findings provide a basis for further clinical studies on melatonin as a drug therapeutic for idiopathic scoliosis.