WMT could effectively induce clinical response and maintain remission in patients with Inflammatory bowel disease (IBD). VD maintains gut microbiota and gut microbiota alter intestinal vitamin D metabolism (VDM),The aim of this study was to evaluate the effect of WMT on VD metabolism by measuring the level of serum 25(OH)D in IBD patients before and after treatment

Inflammatory bowel disease (IBD) is a chronic, relapsing disorder that is represented by Crohn's disease (CD) and Ulcerative colitis (UC), the pathogenesis of IBD is not completely understood, but it is now acknowledged that it is related to intestinal microbiota. The gut microbiota is a central regulator of host metabolism, More and more evidences show that the gut microbiota plays an important physiological role in the pathogenesis of a variety of human metabolic, immune and neurological diseases, including IBD. Fecal microbiota transplantation (FMT) transplants the gut microbiota of healthy donors into the patients' intestines, This is an effective strategy to restore the intestinal microbiota and it is also a hot research topic in recent years. Our previous studies and other studies have proved that FMT could effectively induce clinical response and maintain remission in patients with IBD. Washed microbiota transplantation (WMT) is a fecal bacteria transplantation based on Intelligent fecal bacteria separation system and strict quality control of washing process, It is a new stage of FMT development, our group have proved that WMT is safer, more precise and more quality-controllable than the crude FMT by manual.

Vitamin D(VD) has been shown to have multifaced effects on the skeletal environment,immune system and infection. A number of diseases, including tumors, Type I diabetes, IBD and autoimmune diseases are associated with VD deficiency, VD could have an important role in the prevention and possible treatment of these conditions. Several studies have shown that intestinal microbiota is closely related to VD，VD maintains gut microbiota and gut microbiota alter intestinal vitamin D metabolism (VDM). A clinical trial shows that probiotics supplementation can change the level of 25 hydroxyvitaminD(25(OH)D). Serum 25(OH)D correlates with overall storage of VD, which is the preferred clinical measure to assess VD sufficiency. The aim of this study was to evaluate the effect of WMT on VD metabolism by measuring the level of serum 25(OH)D in IBD patients before and after treatment

Inclusion Criteria:

• IBD patients aged 16-65years

Exclusion Criteria:

• previous history of partial small bowel resection;
• Abnormal thyroid and parathyroid function;
• Complicated with complicated intestinal fistula and severe infection and treated with antibiotics
• Women during pregnancy, lactation and oral contraceptives.

all patients with UC or CD were recruited from the Second Affiliated Hospital of Nanjing Medical University between March 2016 and June 2021