Résumé
BACKGROUND:Many clinical research observations have indicated a close association between rheumatoid arthritis and osteoporosis as well as bone mineral density(BMD).However,it remains unclear whether there is a causal genetic relationship between rheumatoid arthritis and the development of osteoporosis and alterations of BMD. OBJECTIVE:To assess the potential causal relationship between rheumatoid arthritis and osteoporosis as well as BMD using a two-sample Mendelian randomization approach,provide meaningful insights from a genetic perspective into the underlying mechanisms and offer a reference for early prevention of osteoporosis and improvement in the progression of the disease. METHODS:We conducted a study using data from publicly available genome-wide association studies databases to identify single nucleotide polymorphisms associated with rheumatoid arthritis as instrumental variables(P＜5×10-8).The main outcomes of the study included osteoporosis and BMD at five different sites,including total body BMD,lumbar spine BMD,femoral neck BMD,heel BMD,and forearm BMD.The inverse variance-weighted method was used as the primary analysis method to evaluate causal effects.Weighted median,simple median,weighted mode and MR-Egger regression were used as supplementary analyses.Causal relationships between rheumatoid arthritis and the risk of osteoporosis and BMD were assessed using odds ratios(OR)and 95%confidence intervals(CI).Heterogeneity was assessed using Cochran's Q test and horizontal pleiotropy was evaluated using MR-Egger intercept tests. RESULTS AND CONCLUSION:The inverse variance-weighted analysis demonstrated a positive association between genetically predicted rheumatoid arthritis and osteoporosis(OR=1.123,95%CI:1.077-1.171;P=4.02×10-8).Heterogeneity test(P=0.388)indicated no significant heterogeneity among the single nucleotide polymorphisms.MR-Egger intercept(P=0.571)tests did not detect horizontal pleiotropy,and sensitivity analysis showed no evidence of bias in the study results.There was no causal relationship between rheumatoid arthritis and BMD at the five different sites.The total body BMD(OR=1.000,95%CI:0.988-1.012;P=0.925),lumbar spine BMD(OR=0.999,95%CI:0.982-1.016;P=0.937),femoral neck BMD(OR=1.001,95%CI:0.986-1.016;P=0.866),heel BMD(OR=0.996,95%CI:0.989-1.004;P=0.419),and forearm BMD(OR=1.063,95%CI:0.970-1.031;P=0.996)indicated no significant association.MR-Egger intercept analysis did not detect potential horizontal pleiotropy(total body BMD:P=0.253;lumbar spine BMD:P=0.638;femoral neck BMD:P=0.553;heel BMD:P=0.444;forearm BMD:P=0.079).Rheumatoid arthritis may contribute to the development of osteoporosis through the interaction between chronic inflammation and bone formation,resorption,and absorption.Additionally,the use of glucocorticoids and the presence of autoantibodies(such as anti-citrullinated protein antibody)in patients with rheumatoid arthritis showed associations with osteoporosis.Future research should focus on monitoring systemic inflammatory markers,standardized use of glucocorticoids,and regular screening for osteoporosis risk in patients with rheumatoid arthritis.
Résumé
BACKGROUND:Recent studies have shown that the occurrence and prevention of osteoporosis often focus on the cellular molecular level,and the mechanism of related signaling pathways is an important way to further understand osteoporosis.At present,traditional Chinese medicine has been proved to play a significant role in alleviating osteoporosis.Kaempferol as an emerging Chinese herbal extract has become the focus of clinical and basic research due to its anti-osteoporosis effectiveness and mechanism of action. OBJECTIVE:To further understand the mechanism underlying the anti-osteoporosis effect of kaempferol active monomer through regulation of related signaling pathways by analyzing and collating domestic and foreign literature. METHODS:"Kaempferol,osteoporosis,osteoblasts,osteoclasts,bone marrow mesenchymal stem cells,signaling pathways"were used as Chinese and English search terms to search CNKI,WanFang,VIP,PubMed,Web of Science and Embase databases for relevant literature published from database inception to February 2023. RESULTS AND CONCLUSION:Kaempferol affects the occurrence and progression of osteoporosis to varying degrees by participating in the regulation of differentiation,proliferation and apoptosis of bone marrow mesenchymal stem cells,osteoblasts and osteoclasts.Kaempferol can prevent and treat osteoporosis by regulating various signaling pathways.Kaempferol can promote the proliferation and differentiation of osteoblasts and inhibit the formation of osteoclasts by interfering with the Wnt/β-catenin signaling pathway to regulate β-catenin protein counting and the formation of β-catenin-TCf/LEF complex.Kaempferol interferes with the RANK/RANKL pathway to maintain the dynamic balance of osteoclasts and bone homeostasis.Kaempferol can promote bone formation by intervening with the PI3K/Akt signaling pathway to upregulate the levels of related osteogenic factors Runx2 and Osterix and promote bone cell calcification.Kaempferol interferes with osteoclast differentiation and inhibits reactive oxygen species activity by regulating the ER/ERK pathway.Kaempferol inhibits the expression of ERK,JNK,p38/MAPK and decreases reactive oxygen species production by interfering with the MAPK pathway,thus protecting osteogenesis.Kaempferol enhances the expression of osteogenic factors,bone morphogenetic protein-2,p-Smad1/5/8,β-catenin and Runx2,inhibits the expression of Peroxisome proliferation-activated receptor,and promotes the differentiation and proliferation of osteoblasts through the BMP/Smad pathway.