Study On The Relationship Between Vitamin D Signaling,Gut Microbiota And Risk For Colorectal Cancer And Its Mechanisms

Colorectal cancer is a disease associated with gut microbiota.Intestinal mucosal epithelial cell gene mutation causing intestinal mucosal barrier damage and gut microbiota imbalance play a key role in the occurrence of colorectal cancer.Previous studies have confirmed that vitamin D is a protective factor for colorectal cancer.It is not clear what the roles of vitamin D and its signaling pathways play in the relationship between gut microbiota and colorectal cancer.According to the literature,we hypothesized that vitamin D signaling pathway may reduce the risk of colorectal cancer by regulating the gut microbiota structure,maintaining the normal intestinal mucosal barrier,inhibiting the inflammatory response.To test this hypothesis,this study adopted case-control study and case-case-control study design.We tried to explore the relationship between vitamin D signaling pathway,gut microbiota structure and colorectal cancer,to specify vitamin D signaling pathway’s impact on gut microflora and colorectal cancer;We also studied vitamin D’s influence on gut microbiota,intestinal mucosal barrier and chronic inflammation,preliminarily clarify the mechanism of vitamin D signaling pathway in the gut microflora and colorectal cancer.The results could provide theoretical basis for prevention and control of colorectal cancer.Part1.The role of vitamin D signaling pathway in gut microbiota and colorectal cancer relations Objective:By discussing vitamin D,vitamin D receptor expression,the relationship between the gut microbiota and colorectal cancer,understand the role of vitamin D signaling pathway in gut microbiota and colorectal cancer relationship.Methods:This is a case-control study and case-case-control study between 130 patients with colorectal cancer（proximal and distal colorectal cancer,44 cases and 86 cases respectively）and 130 healthy subjects,fecal intestinal bacteria diversity,plasma 25 hydroxyvitamin D levels were detected,and as for the 130 cancer patients,colorectal cancer tissue,cancer adjacent tissue of vitamin D receptor expression and vitamin D signaling pathway were also tested,to explore the relationship between vitamin D signaling pathway,gut microbiota and colorectal cancer.Single factor analysis was performed using Chi-square or t test,and multivariate analysis was performed using multiple Logistic regression analysis method.Results: 1.The relationship between gut microbiota and colorectal cancer（1）Gut microbiota structure was compared between the colorectal cancer group and the control group: Clostridia is the most common flora found in the control group,while in colorectal cancer patients,it’s Fusobacterium.（2）Gut microbiota structure was compared between the proximal colorectal cancer group and the control group: Firmicutes and Fusobacterium are the most common flora found in the control group,while in proximal colorectal cancer patients,they are Proteobacteria and Fusobacterium.（3）Gut microbiota structure was compared between the distal colorectal cancer group and the control group: Firmicutes and Clostridia are the most common flora found in the control group,while in distal colorectal cancer patients,it’s Fusobacterium.2.The relationship between plasma concentration of 25-hydroxy vitamin D,gut microbiota and colorectal cancer（1）When low Plasma 25 hydroxyl vitamin D concentrations,gut microbiota structure was compared between the colorectal cancer group and the control group: Clostridia and Lachnospiraceae are the most common flora found in the control group,while in colorectal cancer patients group,it’s Fusobacterium.（2）When high plasma 25 hydroxy vitamin D concentrations,gut microbiota structure was compared between the colorectal cancer group and the control group: Clostridia and Firmicutes are the most common flora found in the control group,while in colorectal cancer patients,it’s Fusobacterium.3.The relationship between vitamin D receptor expression in the colorectal cancer,gut microbiota and colorectal cancer（1）Gut microbiota structure was compared between the low vitamin D receptor expression of colorectal cancer group and the control group: Clostridia and Firmicutes are the most common flora found in the control group,while in low vitamin D receptor expression of colorectal cancer group,it’s Fusobacterium.（2）Gut microbiota structure was compared between the high vitamin D receptor expression of colorectal cancer group and the control group: Clostridia and Firmicutes are the most common flora found in the control group,while in high vitamin D receptor expression of colorectal cancer group,they are Proteobacteria,Escherichia_Shigella and Fusobacterium.（3）Gut microbiota structure was compared between the low vitamin D receptor expression of colorectal cancer group and the high vitamin D receptor expression of colorectal cancer group: Peptoclostridium and Peptostreptococcaceae are the most common flora found in the low vitamin D receptor expression of colorectal cancer group,while in the high vitamin D receptor expression of colorectal cancer group,it’s Prevotellaceae.4.The relationship between vitamin D signaling pathway,the gut microbiota and colorectal cancer（1）Gut microbiota structure was compared between the vitamin D signaling pathways normal colorectal cancer group and the control group: Lachnospira and Pseudomonadales are the most common flora found in the control group,while in the vitamin D signaling pathways normal colorectal cancer group,they are Prevotellaceae、Fusobacterium and Prevotella.（2）Gut microbiota structure was compared between the vitamin D signaling pathways abnormal colorectal cancer group and the control group: Clostridia、Firmicutes and Lachnospiraceae are the most common flora found in the control group,while in the vitamin D signaling pathways abnormal colorectal cancer group,they are Prevotellaceae、Fusobacterium and Porphyromonadaceae、Porphyromonas and Prevotella.（3）Gut microbiota structure was compared between the vitamin D signaling pathways normal colorectal cancer group and the vitamin D signaling pathways abnormal colorectal cancer group: Prevotellaceae、Roseburia and Peptostreptococcaceae are the most common flora found in the vitamin D signaling pathways normal colorectal cancer group,while in the vitamin D signaling pathways abnormal colorectal cancer group,they are Fusobacterium and Synergistetes.Conclusion:Gut microbiota structure is closely associated with colorectal cancer incidence,vitamin D signaling pathway has an important effect on the gut microbiota and colorectal cancer.Part2.Vitamin D signaling pathway’s action mechanism in the relation between gut microbiota and colorectal cancer Objective:To elucidate vitamin D signaling pathway’s action mechanism in the relation between gut microbiota and colorectal cancer,we investigated vitamin D’s impact on gut microbiota,as well as intestinal mucosal barrier,chronic inflammation.Methods:This is the case-control study and case-case-control study between 130 patients with colorectal cancer（proximal and distal colorectal cancer,44 cases and 86 cases respectively）and 130 healthy subjects,fecal intestinal bacteria diversity,plasma 25 hydroxyvitamin D levels、IL-6、CRP、endotoxin were detected,and as for the 130 cancer patients,colorectal cancer tissue,cancer adjacent tissue of vitamin D receptor expression and vitamin D signaling pathway were also tested,to explore the relationship between vitamin D signaling pathway,gut microbiota and colorectal cancer.Single factor analysis was performed using Chi-square or t test,and multivariate analysis was performed using multiple Logistic regression analysis method.Results: 1.The effect of vitamin D on gut microbiota（1）colorectal cancer groupGut microbiota structure was compared between the high plasma 25-hydroxyl vitamin D concentration and low plasma 25-hydroxy vitamin D concentration: Peptostreptococcaceae is the most common flora found in the the high plasma 25-hydroxyl vitamin D concentration colorectal cancer group,while in the low plasma 25-hydroxy vitamin D concentration colorectal cancer group,they are Megamonas and Parasutterella.（2）control groupGut microbiota structure was compared between the high plasma 25-hydroxyl vitamin D concentration and low plasma 25-hydroxy vitamin D concentration: Lachnospiraceae_UCG₀01 is the most common flora found in the the high plasma 25-hydroxyl vitamin D concentration control group,while in the low plasma 25-hydroxy vitamin D concentration control group,they are Roseburia and Incertae_Sedis.2.The relationship between vitamin D and intestinal mucosal barrier（1）colorectal cancer group: plasma endotoxin concentration was compared between colorectal cancer patients with high plasma 25-hydroxyl vitamin D concentration and low plasma 25-hydroxyl vitamin D concentrationUnivariate analysis showed physical activity,intake of fruit,tea and onions have a significant difference in the two groups（P <0.1）.There was no significant difference of plasma endotoxin concentrations in the two groups（t=1.083,P = 0.281）.Multivariate analysis showed controlling for intake of fruits,tea,onion intake and other factors,the relative risk of plasma endotoxin levels（95% CI）is 1.06（0.98,1.16）,which proves that plasma vitamin D levels and plasma endotoxin levels have no statistical significance（P = 0.158）.（2）control group: plasma endotoxin concentration was compared between control group with high plasma 25-hydroxyl vitamin D concentration and low plasma 25-hydroxyl vitamin D concentrationUnivariate analysis showed NSAIDs,green vegetables,eggs have a significant difference in the two groups（P<0.1）.There was no significant difference of plasma endotoxin concentrations in the two groups（t=1.608,P = 0.110）.Multivariate analysis showed controlling for intake of eggs and other factors,the relative risk of plasma endotoxin levels（95% CI）is 0.94（0.87,1.02）,indicating that plasma vitamin D levels and plasma endotoxin levels have no satistical significance（P = 0.146）.3.The relationship between vitamin D and inflammatory reaction（1）colorectal cancer group: plasma C-reactive protein concentration was compared between colorectal cancer patients with high plasma 25-hydroxyl vitamin D concentration and low plasma 25-hydroxyl vitamin D concentrationUnivariate analysis showed that physical activity,fruit,tea,onions have a significant difference in the two groups（P<0.1）.There was no significant difference of plasma C-reactive protein concentrations in the two group（t=1.502,P = 0.136）.Multivariate analysis showed controlling for intake of fruits,tea,onion intake and other factors,the relative risk of plasma C-reactive protein levels（95% CI）is 0.92（0.82,1.02）,indicating that plasma vitamin D and plasma C-reactive protein levels have no satistical significance（P = 0.129）.（2）control group: plasma C-reactive protein concentration was compared between control group with high plasma 25-hydroxyl vitamin D concentration and low plasma 25-hydroxyl vitamin D concentrationUnivariate analysis showed NSAIDs,green vegetables,eggs have a significant difference in the two groups（P<0.1）.There was no significant difference of plasma C-reactive protein concentrations in the two groups（t=0.428,P = 0.669）.Multivariate analysis showed controlling for intake of eggs and other factors,the relative risk of plasma C-reactive protein levels（95% CI）is 1.03（0.87,1.21）,indicating that plasma vitamin D and plasma C-reactive protein levels have no satistical significance（P = 0.748）.（3）colorectal cancer group: plasma IL-6 concentration was compared between colorectal cancer patients with high plasma 25-hydroxyl vitamin D concentration and low plasma 25-hydroxyl vitamin D concentrationUnivariate analysis showed physical activity,fruit,tea,onions have a significant difference in the two groups（P<0.1）.There was no significant difference of plasma IL-6 concentration in the two groups（t=1.438,P = 0.154）.Multivariate analysis showed controlling for intake of fruits,tea,onion intake and other factors,the relative risk of plasma IL-6 levels（95% CI）is 0.97（0.91,1.03）,indicating that plasma vitamin D levels and serum IL-6 levels have no satistical significance（P = 0.271）.（4）control group: plasma IL-6 concentration was compared between control group with high plasma 25-hydroxyl vitamin D concentration and low plasma 25-hydroxyl vitamin D concentrationUnivariate analysis showed NSAIDs,green vegetables,eggs have a significant difference in the two groups（P<0.1）.There was no significant difference of plasma IL-6 concentrations in the two group（t=0.620,P = 0.536）.Multivariate analysis showed that controlling for intake of eggs and other factors,the relative risk of plasma IL-6 levels（95% CI）is 1.01（0.98,1.05）,indicating that plasma vitamin D levels and serum IL-6 levels have no satistical significance（P = 0.476）.（5）colorectal cancer group: plasma sTNFR2 comparison was compared between colorectal cancer patients with high plasma 25-hydroxyl vitamin D concentration and low high plasma 25-hydroxyl vitamin D concentrationUnivariate analysis showed physical activity,fruit,tea,onions have a significant difference in the two groups（P<0.1）.There was significant difference of plasma sTNFR2 concentrations in the two groups（t=1.738,P = 0.085）.Multivariate analysis showed controlling for intake of fruits,tea,onion intake and other factors,the relative risk of plasma sTNFR2 levels（95% CI）is 0.97（0.99,1.00）,indicating that plasma vitamin D levels and plasma sTNFR2 levels have satistical significance（P = 0.022）.（6）control group: plasma sTNFR2 comparison was compared between control group with high plasma 25-hydroxyl vitamin D concentration and low plasma 25-hydroxyl vitamin D concentrationUnivariate analysis showed NSAIDs,green vegetables,eggs have a significant difference in the two groups（P<0.1）.There was no significant difference of plasma sTNFR2 concentrations in the two groups（t=1.437,P = 0.153）.Multivariate analysis showed controlling for intake of eggs and other factors,the relative risk of plasma s TNFR2 levels（95% CI）is 1.00（1.00,1.01）,indicating that plasma vitamin D levels and plasma sTNFR2 levels have no satistical significance（P = 0.275）.Conclusion:Vitamin D may reduce the gut microbiota and sTNFR2 concentrations,inhibit inflammation,thereby reduce the risk of colorectal cancer.