Inclusion Criteria:
1. Adults between 18 and 55 years of age.
2. Documented functional neurological damage to the central nervous system from closed head trauma that is unlikely to improve with present standard of care approaches.
3. A Glasgow Outcome Scale-Extended (GOS-E) score \>2 and ≤6.
4. Onset or diagnosis of the injury or disease process greater than 6 months and \<= 20 years.
5. Ability to obtain consent from the subject or their legally authorized representative (LAR).
6. Ability to verbally communicate in English or Spanish (required for validated neurocognitive outcome testing).
Exclusion Criteria:
1. Known history of:
1. intellectual deficiency or uncontrolled psychiatric conditions likely to invalidate our ability to assess changes in cognition or behavior, or at the discretion of the PI,
2. recently treated infection,
3. renal disease or altered renal function (screening eGFR \< 60 mL/min/1.73m2),
4. hepatic disease or altered liver function (screening SGPT \> 150 U/L or T. Bilirubin \>1.3 mg/dL),
5. cancer,
6. immunosuppression (screening WBC \< 3, 000 cells/ml),
7. Positive infectious disease tests including HIV, Hep. B, Hep. C., and Syphilis,
8. chemical or ETOH dependency that in the opinion of the investigator would preclude enrollment,
9. acute or chronic lung disease requiring significant medication/oxygen supplementation,
10. bleeding disorders including immune-mediated heparin-induced thrombocytopenia,
11. known sensitivity to heparin, Lovenox, and pork products,
12. individuals with mechanical prosthetic heart valves,
13. individuals who have received a stem cell treatment, gene or cellular therapy.
2. Normal brain CT/MRI exam.
3. History of spinal cord injury.
4. Diagnosed with a genetic or metabolic disorder related to the neurologic condition.
5. Other acute or chronic medical conditions that, in the opinion of the investigator, may increase the risks associated with study participation.
6. For women of childbearing potential, a positive pregnancy test at the screening visit or, for both women and men, unwillingness to comply with acceptable methods of birth control.
7. Concurrent participation in interventional drug or device study.
8. Inability to undergo the diagnostic tests (PET/DT-MRI) or unwilling/unable to cooperate with the diagnostic tests and outcome assessments.
9. Metal implants including baclofen pumps that would preclude DT-MRI.
10. Unwilling or unable to return for the follow-up study visits.
