Fecal Microbiota Transplant for Anorexia Nervosa

The number of participants who are consented into the study divided by the number of participants who show interest in the study.

The number of participants who completed the study divided by the number of participants consented into the study.

Attitudes towards FMT will be studied via semi-structured qualitative interviews of all participants: the 20 adolescents and their parents in the trial, and the 10 adolescents and their parents who decline participation, and their guardians. Using Qualitative Description, interviews will explore patient and guardian attitudes toward FMT, as well as their impressions of efficacy (if they participated in the trial). Questions will include perceptions of "natural" versus "drug" products, perspectives on causes of AN, and interests in other potential treatments. Interviews will be conducted virtually, using Zoom for Healthcare, transcribed verbatim and then coded for themes using NVivo. This analysis stays close to the data with little to no interpretation. Our analysis will also include a summative content analysis.

Height will be collected.

Weight will be measured between hospital visits using home weight scales provided to study participants.

The EDEQ is a 28-item standardized questionnaire that measures the severity of symptoms of eating disorders, including menstrual status.

The BDI is a 21-item questionnaire used to measure the severity of depressive symptoms.

The BAI is a 21-item questionnaire used to measure the severity of anxiety symptoms.

The YBC-EDS assesses impairment, persistence and degree of obsessional thinking and compulsiveness about eating behaviors.

This is a 15-item rating scale to capture a variety of GI symptoms.

Stool will be collected in to examine changes in alpha- and beta- diversity of microbiota, as well as engraftment of donor specific strains/genes and microbially-derived metabolite levels throughout the study. All stool samples will be collected using an at-home collection kit. Samples will be collected and stored in locked, secure -80°C study freezers upon being brought to the hospital or shipped by paid courier by participants. Stool samples will be sequenced for 16s rRNA gene profiling. All 16s rRNA analyses will be performed using in-house bioinformatics pipelines through the laboratory of a collaborator to identify amplicon sequence variants, perform taxonomic assignments, and analyze alpha- and beta-diversity and differential taxonomic abundance.

Urine samples will be collected from each participant. Nontargeted metabolite profiling is a method used to explore and identify as many metabolites as possible in a sample to identify whatever is present. This approach is designed to help discover new metabolites, and identify changes in metabolite levels that may correlate with other outcomes. We will report differences in highest-abundance metabolites using t-tests to compare their presence between groups, and correlation coefficients to identify associations between outcomes.

Saliva samples will be collected for metabolomic analysis. Saliva ultrafiltrates will be analyzed as described above for stool and urine samples by a collaborator. All saliva ultrafiltrates will be reported using the same multisegment injection-capillary electrophoresis-mass spectrometer, where metabolites are reported using effect sizes to compare relative concentrations against reference standards.

Using the provided blood samples, changes in complete blood count from baseline to post-intervention will be compared using paired t-tests. The complete blood count includes (with their measurement units):

Red blood count (RBC)- cells/L Hemoglobin (Hb)- g/L Hematocrit- L/L Mean corpuscular volume (MCV)- fL Mean Corpuscular Hemoglobin (MCH)- pg Mean corpuscular hemoglobin concentration (MCHC)- g/L Red cell distribution width (RDW)- % White blood count (WBC) - cells/L Neutrophils - cells/L Lymphocytes - cells/L Eosinophils - cells/L Basophils - cells/L Monocytes - cells/L

Using the provided blood samples, changes in C-reactive protein (CRP) from baseline to post-intervention will be compared using paired t-tests. CRP (measured in mg/L) is used to monitor inflammation in acute or chronic conditions.

Using the provided blood samples, changes in alkaline phosphatase (ALP) from baseline to post-intervention will be compared using paired t-tests. ALP (measured in U/L) is associated with liver function.

Using the provided blood samples, changes in alanine aminotransferase (ALT) from baseline to post-intervention will be compared using paired t-tests. ALT (measured in U/L) is associated with liver function.

Using the provided blood samples, changes in 25-OH Vitamin D from baseline to post-intervention will be compared using paired t-tests. 25-OH Vitamin D (measured in ng/ml) is used as a measure of Vitamin D levels.

Using the provided blood samples, changes in albumin from baseline to post-intervention will be compared using paired t-tests. Albumin (measured in g/L) is associated with liver and kidney function.

Using the provided blood samples, changes in follicle stimulating hormone (FSH) from baseline to post-intervention will be compared using paired t-tests. FSH (measured in mIU/mL) is important for determining aspects of fertility and menstruation.

Using the provided blood samples, changes in luteinizing hormone (LH) from baseline to post-intervention will be compared using paired t-tests. LH (measured in IU/L) is important for determining aspects of fertility and menstruation.

Using the provided blood samples, changes in free testosterone from baseline to post-intervention will be compared using paired t-tests. Free testosterone (measured in nmol/L) is important for assessing various bodily functions related to hormones.

Common Terminology Criteria for Adverse Events (CTCAE) will be used to define adverse events and serious adverse events. This framework will be used to classify broad safety concerns throughout our trial.