BACKGROUND:Alzheimer's disease has been associated with sarcopenia,but a causal relationship has not been established.Exploring the causal relationship between the two most common disability-burdening diseases in the aging population-Alzheimer's disease and sarcopenia-and their potential mediating factors holds certain implications for further alleviating the healthcare costs and socioeconomic burden for older adults in China.OBJECTIVE:To explore the potential causal relationship between Alzheimer's disease and sarcopenia in the general population using a Mendelian randomization study and to explore the role of body mass index in this context.METHODS:Two-sample Mendelian randomization analysis based on published genome-wide association studies(GWAS)were used to infer causality,and univariate Mendelian randomization and mediation analyses were used in the study design.Through the Integrative Epidemiology Unit(IEU)database,ieu-b-2 was selected as the Alzheimer's disease dataset(sample size:63 926),ieu-b-4816 as the body mass index dataset(99 998),ebi-a-GCST90000027 as the appendicular lean mass dataset(244 730),ukb-b-7478 as the left hand grip strength dataset(461 026),ukb-b-10215 as the right hand grip strength dataset(461 089)and ukb-b-4711 as the walking pace dataset(459 915).Inverse-variance weighting was used as the primary analysis method,and the results were validated by pleiotropy and heterogeneity analysis.The Steiger Directionality Test was performed to validate the reasonableness of the causal direction.RESULTS AND CONCLUSION:(1)The Mendelian randomization analyses provided evidence that Alzheimer's disease predicted the risk of appendicular lean mass[odds ratio(OR)=1.009;95％confidence interval(Cl),1.001-1.017;P=0.023),and walking pace(OR=1.010;95％Cl,1.003-1.017;P=0.008).No correlation with hand grip strength was observed.(2)Alzheimer's disease was negatively correlated with body mass index(OR=0.893;95％Cl,0.811-0.984;P=0.022);body mass index was positively correlated with appendicular lean mass(OR=1.084;95％Cl,1.031-1.141;P=0.002)and negatively correlated with walking pace(OR=0.975;95％Cl,0.969-0.980;P＜0.001).(3)Mediation analyses showed that the causal relationship between Alzheimer's disease and appendicular lean mass and walking pace was partially mediated by body mass index,with the proportion of mediations being 50.25％and 32.11％,respectively.(4)The results of this study suggest that based on large-scale population studies,genetic prediction of Alzheimer's disease is a potential risk factor for sarcopenia,in which body mass index plays an important mediating role.This suggests that in clinical practice,attention should be paid to the muscle condition of patients with Alzheimer's disease,and weight management should be implemented,as maintaining a body mass index within the normal high range may have a preventive effect on the occurrence of sarcopenia in patients with Alzheimer's disease.However,further research is needed to verify the applicability of this conclusion to other ethnic groups.This study utilized an international public database for analysis,providing a reference for research on the correlation between Alzheimer's disease and sarcopenia in the Chinese population.It also highlights the significant mediating role of body mass index,offering insights for further prevention and treatment of sarcopenia among Chinese individuals.

BACKGROUND:Alzheimer's disease has been associated with sarcopenia,but a causal relationship has not been established.Exploring the causal relationship between the two most common disability-burdening diseases in the aging population-Alzheimer's disease and sarcopenia-and their potential mediating factors holds certain implications for further alleviating the healthcare costs and socioeconomic burden for older adults in China.OBJECTIVE:To explore the potential causal relationship between Alzheimer's disease and sarcopenia in the general population using a Mendelian randomization study and to explore the role of body mass index in this context.METHODS:Two-sample Mendelian randomization analysis based on published genome-wide association studies(GWAS)were used to infer causality,and univariate Mendelian randomization and mediation analyses were used in the study design.Through the Integrative Epidemiology Unit(IEU)database,ieu-b-2 was selected as the Alzheimer's disease dataset(sample size:63 926),ieu-b-4816 as the body mass index dataset(99 998),ebi-a-GCST90000027 as the appendicular lean mass dataset(244 730),ukb-b-7478 as the left hand grip strength dataset(461 026),ukb-b-10215 as the right hand grip strength dataset(461 089)and ukb-b-4711 as the walking pace dataset(459 915).Inverse-variance weighting was used as the primary analysis method,and the results were validated by pleiotropy and heterogeneity analysis.The Steiger Directionality Test was performed to validate the reasonableness of the causal direction.RESULTS AND CONCLUSION:(1)The Mendelian randomization analyses provided evidence that Alzheimer's disease predicted the risk of appendicular lean mass[odds ratio(OR)=1.009;95％confidence interval(Cl),1.001-1.017;P=0.023),and walking pace(OR=1.010;95％Cl,1.003-1.017;P=0.008).No correlation with hand grip strength was observed.(2)Alzheimer's disease was negatively correlated with body mass index(OR=0.893;95％Cl,0.811-0.984;P=0.022);body mass index was positively correlated with appendicular lean mass(OR=1.084;95％Cl,1.031-1.141;P=0.002)and negatively correlated with walking pace(OR=0.975;95％Cl,0.969-0.980;P＜0.001).(3)Mediation analyses showed that the causal relationship between Alzheimer's disease and appendicular lean mass and walking pace was partially mediated by body mass index,with the proportion of mediations being 50.25％and 32.11％,respectively.(4)The results of this study suggest that based on large-scale population studies,genetic prediction of Alzheimer's disease is a potential risk factor for sarcopenia,in which body mass index plays an important mediating role.This suggests that in clinical practice,attention should be paid to the muscle condition of patients with Alzheimer's disease,and weight management should be implemented,as maintaining a body mass index within the normal high range may have a preventive effect on the occurrence of sarcopenia in patients with Alzheimer's disease.However,further research is needed to verify the applicability of this conclusion to other ethnic groups.This study utilized an international public database for analysis,providing a reference for research on the correlation between Alzheimer's disease and sarcopenia in the Chinese population.It also highlights the significant mediating role of body mass index,offering insights for further prevention and treatment of sarcopenia among Chinese individuals.

With the main pathological features of glomerulosclerosis and interstitial fibrosis， renal fibrosis is a key pathological process causing chronic kidney disease to progress to end-stage disease. As a cellular autophagic process， mitochondrial autophagy plays a crucial role in maintaining mitochondrial mass and functional stability. Mitochondrial dysfunction is considered to be one of the key factors driving the progression of fibrosis. Phosphatase and tension protein homologue （PTEN） induce various signalling pathways such as putative kinase 1/parkin， Nip3-like protein X/Bcl-2 interacting protein 3， and FUN14 structural domain-containing protein 1 to activate mitochondrial autophagy to participate in the regulation of fibrogenic factors， amelioration of oxidative stress， and inhibition of inflammatory response and apoptosis， which in turn effectively slows down the progression of renal fibrosis. Studies have shown that traditional Chinese medicine monomers and compound preparations， including phenolics， terpenoids， ketones， and alkaloids， can regulate mitochondrial autophagy-related signalling pathways and achieve significant clinical efficacy in intervening in the progression of renal fibrosis for the treatment of chronic kidney disease. This paper summarized the mechanism of mitochondrial autophagy and the research progress of traditional Chinese medicine intervention in renal fibrosis to provide new ideas for the study of the mechanism of traditional Chinese medicine in treating renal fibrosis.

With the main pathological features of glomerulosclerosis and interstitial fibrosis， renal fibrosis is a key pathological process causing chronic kidney disease to progress to end-stage disease. As a cellular autophagic process， mitochondrial autophagy plays a crucial role in maintaining mitochondrial mass and functional stability. Mitochondrial dysfunction is considered to be one of the key factors driving the progression of fibrosis. Phosphatase and tension protein homologue （PTEN） induce various signalling pathways such as putative kinase 1/parkin， Nip3-like protein X/Bcl-2 interacting protein 3， and FUN14 structural domain-containing protein 1 to activate mitochondrial autophagy to participate in the regulation of fibrogenic factors， amelioration of oxidative stress， and inhibition of inflammatory response and apoptosis， which in turn effectively slows down the progression of renal fibrosis. Studies have shown that traditional Chinese medicine monomers and compound preparations， including phenolics， terpenoids， ketones， and alkaloids， can regulate mitochondrial autophagy-related signalling pathways and achieve significant clinical efficacy in intervening in the progression of renal fibrosis for the treatment of chronic kidney disease. This paper summarized the mechanism of mitochondrial autophagy and the research progress of traditional Chinese medicine intervention in renal fibrosis to provide new ideas for the study of the mechanism of traditional Chinese medicine in treating renal fibrosis.

Objective In the present study, we investigated the effects of advanced oxidation protein products(AOPP) on reactive oxygen species(ROS) production in murine osteoblastic MC3T3-E1 cells by NADPH oxidase enzymes pathway. Methods Experiments were divided into three groups, including control group, rats albumin(RSA) group, and AOPP group. Different concentrations of AOPP were added to the osteoblastic MC3T3-E1 cells culture medium. The production of ROS in MC3T3-E1 cells was measured by the fluorescence intensity of intracellular fluoroprobe ( DCFD ) . In order to verify the effect of enzyme of the production of ROS, the specific inhibitors of corresponding enzymes were added in the MC3T3-E1 cells which were cultured in the medium with AOPP. Finally, western blot and immunofluorescence were used to observe the changes of NADPH oxidase enzymes subunits. Results Different concentrations of AOPP (50,100,200μg/ml) induced MC3T3-E1 cells to produce different amount of ROS. The higher concentrations of AOPP were added, the more ROS were produced. Furthermore,200μg/ml AOPP induced the maximum amount of ROS production(P<0. 05). Meanwhile, AOPP induced MC3T3-E1 cells to produce different amount of ROS with a time-dependent manner. The peak amount of ROS production in MC3T3-E1 cells was observed in 3h when AOPP were added (P<0. 05). In addition, when specific inhibitors of corresponding enzymes were added in the MC3T3-E1 cells, the production of ROS were significantly suppressed by C-SOD, DPI, and apocynin(P<0. 05). On the other hand, AOPP can up-regulate the expression of Nox4 protein of the MC3T3-E1 cells, which is one of the subunits of NADPH oxidase enzymes. Meanwhile, AOPP can also induce the membrane migration of p47phox subunit. Conclusion AOPP induces osteoblastic MC3T3-E1 cells to produce ROS by NADPH oxidase enzymes pathway, and which may be one of the pathogenesis of AOPP involved in osteoporosis.