The purpose of this research study is to test if adding one infusion of mesenchymal stem cells to the current treatment with antipsychotic medication may help control behavioral problems in people with a diagnosis of moderate to severe Alzheimer's disease.

Inclusion Criteria:

• Adults 55-90 years at the time of signing consent
• A diagnosis of probable Alzheimer disease (AD), defined by the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria
• Previous computed tomography or magnetic resonance imaging scan of the brain with findings consistent with a diagnosis of Alzheimer disease
• A diagnosis of behavioral symptoms that include any of the following: delusions, hallucinations, agitation/aggression, depression/dysphoria, anxiety, elation/euphoria, apathy/indifference, disinhibition, irritability/lability, aberrant motor behavior, sleep and nighttime behavior disorders and appetite and eating disorders
• Onset of behavioral symptoms at least 4 weeks prior to screening.
• Treatment with antipsychotic medication for at least 4 weeks prior to the hMSC infusion.
• Patients unable to consent should have a Legally Authorized Representative or Proxy to provide consent on their behalf.
• Have a family member or friend (study partner) who has frequent and sufficient contact with the patient and able to answer questions about the participant's behavior.

Exclusion Criteria:

• Dementia other than AD
• Patient with severe depression. Patient with controlled depression is allowed to participate.
• Recent history of substance abuse
• History of bleeding disorders, HIV, Hepatitis C Virus or Hepatitis B Virus
• Recent history (within 3 years) of malignancies, except for treated basal cell, squamous carcinoma or melanoma in situ, prostate in situ, cervical carcinoma in situ.
• Uncontrolled medical conditions (hypertension, diabetes, unstable angina or Myocardial Infarction within 1 year prior to screening)
• History of bleeding disorder
• Currently receiving (or received within four weeks of screening) experimental agents for the treatment of Alzheimer's Disease or enrolled in clinical trials in the prior 3 months.
• Be a transplant recipient or in any other active medical condition than in the opinion of the investigator may compromise the safety or compliance of the patient or preclude successful completion of the study
• Be premenopausal