Exploration Of Theimbalance Pattern Of Intestinal Flora In Patients With Diabetic Nephropathy And Analysis Of The Efficacy Of Vitamin D

BackgroundDiabetes,hypertension and obesity are traditional risk factors for chronic kidney disease（CKD）.Diabetic nephropathy（DN）is the main cause of chronic kidney disease and ultimately leads to irreversible kidney failure.The structural changes begin with the hypertrophy of the glomeruli and tubules,accompanied by the thickening of the basement membrane and mesangium,which ultimately leads to end-stage glomerular closure and tubular interstitial fibrosis.There is no specific intervention for diabetic nephropathy,and the number of patients is still high.Activation of renin angiotensin system（RAS）in hyperglycemia is a key factor in DN.Although many clinical studies made it clear that angiotensin converting enzyme inhibitors（ACEI）and angiotensin II receptor blockers（ARB）can significantly reduce the proteinuria and delay the progress of DN,but the main problem with RAS inhibitors was due to the destruction of the feedback inhibition of renin that caused the compensatory renin increase.Experimental and observational studies conducted over the past few years have shown that the effective effects of vitamin D and its synergistic effects with RAS inhibitors counteract the deterioration of DN and maintain the integrity of the glomerulus and the glomerular filtration barrier.In addition,vitamin D appears to play a number of extrarenal functions that are critical to homeostasis in the body.Vitamin D and vitamin D receptors may be a novel treatment for DN.The intestine is the largest endocrine-neurohormonal network in the human body,and the intestinal flora plays a key role in maintaining its homeostasis.One of the important functions of the intestinal flora is to digest food and provide nutrients and energy to the host.Another important function of the intestinal flora is to activate the immune system.The fermentation of prebiotic fibers by intestinal flora leads to the release of metabolites,of which short-chain fatty acids（SCFAs）are one of the most important metabolites,including acetate,propionate and butyrate.Disturbance of the intestinal flora contributes to the production of representative uremia toxins,leads to leakage of pro-inflammatory bacterial products,insulin resistance,immune dysregulation,atherosclerosis,and accelerates the progression of renal disease in patients with diabetes.The development of chronic kidney disease,in turn,affects the composition of the intestinal microbiota,worsens the gastrointestinal environment,increases the permeability of the intestinal epithelial barrier,leads to elevated intestinal pH,and induces both local and systemic inflammation.This complex interrelationship between metabolites derived from the gut microbiome,the gut microbiome itself,and the host aggregates together to form a series of host-microbial metabolic axes.The understanding of intestinal ecosystem based on integromics is helpful to provide new targets and clinical perspectives for the diagnosis and treatment of diabetes.Purposes1.To explore the differences in the types and abundance of intestinal microflora in diabetic nephropathy patients compared with healthy and non-diabetic nephropathy patients,and based on the results of 16SrRNA high-throughput sequencing,to find intestines with potential diagnostic significance for patients with diabetic nephropathy and non-diabetic nephropathy Flora.2.To evaluate effects of active Vitamin D（VD）on diabetic nephropathy（DN）via a network meta-analysis（NMA）.Methods1.Stool samples were collected from 25 patients with DN,40 age-and sex-matched patients with non-diabetic nephropathy,and 24 age-and sex-matched healthy controls.The composition of microflora was analyzed by 16sRNA gene sequencing.2.We searched PubMed,Embase,Cochrane Library,Wanfang,CNKI and CBM databases,and searched the randomized controlled trials（RCT）of active VD on DN patients published between the establishment of the database and July 2020,and then extracted Relevant data and select the appropriate effect model for meta-analysis.Results1.Significant differences in microbial composition,abundance,and evolutionary relationships have been found in DN compared to HC,DN compared to NN,and NN compared to HC,respectively.The variable of genus g_Faecalibacterium（AUC=0.86）can accurately distinguish between DN and age/gender-matched healthy controls.DN could be well distinguished from age/gender-matched healthy controls by the the variable of genus g_Megamonas（AUC=0.70）,the variable of genus g_Prevotella₉（AUC=0.71）and the variable of genus g_Actinomyces（AUC=0.79）.The variable of genus g Faecalibacterium（AUC=0.88）can also accurately distinguish between DN and age/gender-matched non-diabetic nephropathy group.2.Meta-analysis directly compares results:VD supplementation significantly reduced the urine protein and showed no impact on serum creatinine reduction for DN.VD supplement group failed to effectively reduce glycated hemoglobin while was more effective in reducing hypersensitive C-reactive protein.For estimating glomerular filtration rate,there was no statistically significant difference between VD supplement group versus the control group.The NMA revealed the following:Alfacalcidol combined with RAS inhibitors has the best effect in reducing albumin.For serum creatinine,RAS inhibitor alone group had the most significant effect In terms of reducing urea nitrogen,the most significant curative effect is the spironolactone combined with calcitriol group.Conclusions1.Significant differences in microbial composition and abundance have been found in DN compared to HC,DN compared to NN,and NN compared to HC.Hemodialysis affects the diversity of the intestinal flora to a certain extent.g_Faecalibacterium,g_Megamonas,g_Prevotella 9 and g_Actinomyces have potential distinguishing significance for DN and HC,DN and NN.We found that the following urease and uricase-producing bacteria increased in the DN and NN groups,including f_Clostridiaceae,f_Enterobacteriaceae,f Micrococcaceae,f_Dermabacteraceae,f_Micrococcaceae,and f_Clostridiaceae,f Enterobacteriaceae,which produce tryptophanase,And the average relative abundance is higher in the DN group.At the genus level,we can find that the following short-chain fatty acid-producing bacteria,including g_Faecalibacterium,g_Prevotella₉,g_Roseburia,and g_Subdoligranulum,are reduced in the DN group and the NN group,and the average relative abundance is lower in the DN group.2.VD supplements are effective in reducing urine protein and high-sensitivity C-reactive protein in patients with DN,but have no effect on reducing serum creatinine,glycosylated hemoglobin and improving the estimated glomerular filtration rate.Alfacalcidol combined with RAS inhibitors has the best effect in reducing albumin.For serum creatinine,the RAS inhibitor group alone had the most significant effect.In terms of reducing urea nitrogen,the most significant therapeutic effect is the combination of spironolactone and calcitriol.