Allogeneic Human Mesenchymal Stem Cells (hMSCs) Infusion in Patients With Treatment Resistant Depression

Inclusion Criteria: 1. Provide written informed consent. 2. Subjects age equal or greater than 18 and equal or less than 75 years at the time of signing the Informed Consent Form. 3. Diagnosis of Treatment resistant depression (Failed at least two adequate trials of antidepressant monotherapy or antidepressant augmentation with an antipsychotic or lithium during the current episode) 4. Patients who are receiving a third or more treatment will only be entered if they have not responded to the current treatment. 5. Experiencing a current Major Depressive Episode (fulfilling Structured clinical interview for Diagnostic and Statistical Manual of Mental Disorders (DSM V) criteria per Structured Clinical Interview for DSM (SCID) for categorical diagnosis, and the Hamilton Depression Rating Scale for Depression (HAM-D)) 6. Hamilton Depression Rating Scale 21-item score greater than 18 7. Adequacy of previous failed antidepressant trials will be defined using standard criteria by Massachusetts General Hospital (MGH) of patients with a score greater than or equal to 2.5 8. Increased inflammation (\[Serum CRP\] greater than 3.0 mg/L) Exclusion Criteria: In order to participate in this study, a patient Must Not: 1. Women who are pregnant, nursing, or of childbearing potential, while not practicing effective contraceptive methods. (Female subjects of childbearing potential must undergo a serum or urine pregnancy test at screening and within 36 hours prior to infusion.) 2. Inability to perform any of the assessments required. 3. Have clinically significant abnormal screening laboratory values, including but not limited to: hemoglobin \<8 g/dl, white blood cell count \<3000/mm3, platelets\<80,000/mm3, INR \> 1.5 not due to a reversible cause (i.e. Coumadin), aspartate transaminase, alanine transaminase, or alkaline phosphatase \> 3 times upper limit of normal, total bilirubin \> 1.8 mg/dl (unless due to a benign cause). 4. Active medical condition that could cause or exacerbate depressive symptoms (e.g., hypothyroidism, anemia) 5. Serious comorbid illness or any other condition (Such as bipolar, schizophrenia or schizoaffective disorder) that, in the opinion of the investigator, may compromise the safety or compliance of the subject or preclude successful completion of the study. 6. Have acute suicidality 7. Prior history of a suicide attempt, within the past year. 8. Active psychotic disorder, eating disorder, or substance use disorder within 6 months of enrollment 9. Treatment with any medication that, in the opinion of the Investigator, may compromise the safety of the subject or affect the validity of the data or the study endpoints. 10. First major depressive episode after 50 years of age. 11. Have known allergies to penicillin or streptomycin. 12. Have hypersensitivity to dimethyl sulfoxide (DMSO). 13. Have a clinical history of malignancy within 5 years (i.e., subjects with prior malignancy must be disease free for 5 years), except curatively-treated basal cell carcinoma, squamous cell carcinoma, melanoma in situ or cervical carcinoma. 14. Have a non-pulmonary condition that limits lifespan to \< 1 year. 15. Have a history of drug or alcohol abuse within the past 24 months. 16. Be serum positive for HIV, hepatitis BsAg or Viremic hepatitis C.