PROCHYMAL® (Human Adult Stem Cells) for the Treatment of Recently Diagnosed Type 1 Diabetes Mellitus (T1DM)

Inclusion Criteria: * Participant must have a diagnosis of type 1 diabetes mellitus based on the American Diabetes Association (ADA) criteria. * Participant must be screened between 2 and 20 weeks from initial T1DM diagnosis * Participants must be between the ages of 12 and 35 (inclusive). * Participant must have at least one diabetes-related autoantibody present (either GAD or IA-2). * Participant must have some beta cell function as determined by C-peptide testing (at least 0.2 pmol/mL (0.6 ng/mL) during MMTT. * Participants must be willing to comply with "intensive diabetes management" as directed by the Investigator with the goal of maintaining blood glucose as close to normal as possible (i.e., glycosylated hemoglobin A1c (HbA1c) value of ≤ 7.0%). * Participants must be willing to comply with the schedule of study visits and protocol requirements. Exclusion Criteria: * Participant has Body Mass Index (BMI) ≥ 30. * Participant has evidence of retinopathy at baseline. * Participant has abnormally high lipid levels. * Participant has abnormal blood pressure. * Participant has an abnormal serum creatinine. * Participant has evidence of clinically significant proteinuria. * Participant has diabetic ketoacidosis. * Participant is being treated for a severe active infection of any type. * A female participant who is breast-feeding, pregnant, or intends to become pregnant during the study. * Participant with clinically relevant uncontrolled medical condition not associated with diabetes (e.g. hematologic, renal, hepatic, neurologic, cardiac, or respiratory). * Participant has received an investigational drug (not approved by the FDA) for any indication 30 days prior to the screening visit. * Participant is allergic to bovine or porcine products. * Participant has evidence of active malignancy or prior history of active malignancy that has not been in remission for at least 5 years. * Participant has any medical condition, which in the opinion of the Investigator, rendered his/her participation in this study unsuitable.