Inclusion Criteria:  Males and Females 18-75 years of age Ulcerative colitis of at least 6 months duration with medically refractory symptoms Failed to have improvement of disease while receiving at least one monoclonal antibody (infliximab, adalimumab, certolizumab, golimumab, vedolizumab, ustekinumab) or tofacitinib for 8 weeks duration prior to enrollment. Or has a contra-indication to monoclonal antibodies Exposure to corticosteroids, 5-ASA drugs, thiopurines, methotrexate, anti-TNF therapy, anti-integrin and anti-interleukin in the past are permitted but a washout period of 8 weeks for any monoclonal antibody is necessary. If receiving conventional immunomodulators (ie, AZA, 6-MP, or MTX), must have been taking them for ≥12 weeks, and on a stable dose for at least 4 weeks. If AZA, 6-MP, or MTX has been recently discontinued, it must have been stopped for atleast 4 weeks. If receiving oral 5-ASA compounds, the dose must have been stable for at least 4 weeks. If receiving oral corticosteroids, the dose must be ≤20 mg/day prednisone or its equivalentand must have been stable for at least 4 weeks. If receiving budesonide, the dose must have been stable for at least 2 weeks. If oral 5-ASA compounds or oral corticosteroids (including budesonide) have been recently discontinued, they must have been stopped for at least 2 weeks. The following medications/therapies must have been discontinued before first administration of study agent: TNF-antagonist therapy (e.g. infliximab, etanercept, certolizumab, adalimumab, golimumab, vedolizumab, ustekinumab) for at least 8 weeks. Cyclosporine, tacrolimus, or sirolimus, for at least 4 weeks. 6-thioguanine (6-TG) must have been discontinued for at least 4 weeks. Rectal corticosteroids (ie, corticosteroids [including budesonide] administered to the rectum or sigmoid colon via foam or enema or suppository) for at least 2 weeks. Rectal 5-ASA compounds (ie, 5-ASAs administered to the rectum or sigmoid colon viafoam or enema or suppository) for at least 2 weeks. Parenteral corticosteroids for at least 2 weeks. Total parenteral nutrition (TPN) for at least 2 weeks. Antibiotics for the treatment of UC (eg, ciprofloxacin, metronidazole, or rifaximin) for atleast 2 weeks. No colonic dysplasia and malignancy as ruled out by colonoscopy within 30 days of MSC delivery Ability to comply with protocol Competent and able to provide written informed consent Stated willingness to comply with all study procedures and availability for the duration of the study If patient is of reproductive capacity, willing to use adequate birth control measures while they are in the study  Exclusion Criteria:  Inability to give informed consent. Clinically significant medical conditions within the six months before administration of ExoFlo: e.g. myocardial infarction, active angina, congestive heart failure or other conditions that would, in the opinion of the investigators, compromise the safety of the patient. Patients with confirmed HIV, Hepatitis B, or Hepatitis C infections Abnormal AST or ALT at screening defined as AST >100 or ALT > 100 Abnormal basic laboratory values with the following cut-offs: Alkaline phosphate >200 WBC >13 Hemoglobin <7 Platelets <50 or > 1 million eGRF < 60 HbA1C > 8% Subjects with abnormal coagulation studies: Prothrombin time (PT) > 1.5 times the upper limits of normal Partial thromboplastin time (PTT) > 1.5 times the upper limits of normal International normalized ratio (INR) > 1.5 times the upper limits of normal Subjects with hyperbilirubinemia and evidence of liver disease as defined by AST > 100 or ALT > 100 or PT > 1.5 times the upper limits or normal or PT/INR > 1.5 time the upper limits of normal. Subjects with abnormal vital signs as defined by any of the following: Systolic blood pressure >160 or <90 mmHg Diastolic blood pressure >90 or <60 mmHg Pulse <60 or >105 bpm Respiratory Rate <9 and >25 breaths per minute Temperature: >100.4 degrees Fahrenheit SpO2 : <92% History of cancer including melanoma (with the exception of localized skin cancers) within 5 years of study enrollment Investigational drug within one year of study enrollment Pregnant or breast feeding. If patient is of reproductive capacity, unwilling to use adequate birth control measures while they are in the study Fulminant colitis requiring emergency surgery Concurrent active clostridium difficile infection of the colon Concurrent CMV infection of the colon Evidence of colonic perforation Massive hemorrhage from the colon requiring emergent surgery Crohn's colitis or indeterminate colitis Microscopic, ischemic or infectious colitis Neoplasia of the colon and preoperative biopsy Presence of an ostomy Prior small bowel resection Previous colonic resection Colonic stricture that unable to pass an adult colonoscope Active or latent tuberculosis Unable to wean off corticosteroids Patients with extra colonic ulcerative colitis including primary sclerosing cholangitis Patients with history of or current evidence of alcohol or drug abuse or dependence, recreational use of illicit drug or prescription medications, or have use of medical marijuana within 90 days of study entry Patients with known allergy to local anesthetics Patients taking anticoagulant medications (e.g. warfarin, heparin) or clopidogrel (Plavix) to reduce the risk of bleeding/ hemarthrosis Individuals with inherited or acquired hypercoagulable states, history of thromboembolic events or bleeding disorders Electrocardiogram demonstrating cardiac arrhythmia, except for sinus tachycardia within the predefined limit of no greater than 105 bpm.