Progenitor cells: therapeutic targets after traumatic brain injury

Traumatic brain injury and stem cell treatments: A review of recent 10 years clinical trials

Traumatic brain injury (TBI) is damage to the brain by an external physical force. It may result in cognitive and physical dysfunction. It is one of the main causes of disability and death all around the world. In 2016, the worldwide incidence of acute TBI was nearly 27 million cases. Therapeutic interventions currently in use provide poor outcomes. So recent research has focused on stem cells as a potential treatment. The major objective of this study was to conduct a systematic review of the recent clinical trials in the field of stem cell transplantation for patients with TBI. The Cochrane Library, Web of Science, SCOPUS, PubMed and also Google Scholar were searched for relevant terms such as "traumatic brain injury", " brain trauma", "brain injury", "head injury", "TBI", "stem cell", and "cell transplantation" and for publications from January 2013 to June 2023. Clinical trials and case series which utilized stem cells for TBI treatment were included. The data about case selection and sample size, mechanism of injury, time between primary injury and cell transplantation, type of stem cells transplanted, route of stem cell administration, number of cells transplanted, episodes of transplantation, follow-up time, outcome measures and results, and adverse events were extracted. Finally, 11 studies met the defined criteria and were included in the review. The total sample size of all studies was 402, consisting of 249 cases of stem cell transplantation and 153 control subjects. The most commonly used cells were BMMNCs, the preferred route of transplantation was intrathecal transplantation, and all studies reported improvement in clinical, radiologic, or biochemical markers after transplantation. No serious adverse events were reported. Stem cell therapy is safe and logistically feasible and leads to neurological improvement in patients with traumatic brain injury. However, further controlled, randomized, multicenter studies with large sample sizes are needed to determine the optimal cell and dose, timing of transplantation in acute or chronic phases of TBI, and the optimal route and number of transplants.

Time dependent analysis of rat microglial surface markers in traumatic brain injury reveals dynamics of distinct cell subpopulations

Traumatic brain injury (TBI) results in a cascade of cellular responses, which produce neuroinflammation, partly due to the activation of microglia. Accurate identification of microglial populations is key to understanding therapeutic approaches that modify microglial responses to TBI and improve long-term outcome measures. Notably, previous studies often utilized an outdated convention to describe microglial phenotypes. We conducted a temporal analysis of the response to controlled cortical impact (CCI) in rat microglia between ipsilateral and contralateral hemispheres across seven time points, identified microglia through expression of activation markers including CD45, CD11b/c, and p2y12 receptor and evaluated their activation state using additional markers of CD32, CD86, RT1B, CD200R, and CD163. We identified unique sub-populations of microglial cells that express individual or combination of activation markers across time points. We further portrayed how the size of these sub-populations changes through time, corresponding to stages in TBI response. We described longitudinal changes in microglial population after CCI in two different locations using activation markers, showing clear separation into cellular sub-populations that feature different temporal patterns of markers after injury. These changes may aid in understanding the symptomatic progression following TBI and help define microglial subpopulations beyond the outdated M1/M2 paradigm.

What's New in Traumatic Brain Injury: Update on Tracking, Monitoring and Treatment

Traumatic brain injury (TBI), defined as an alteration in brain functions caused by an external force, is responsible for high morbidity and mortality around the world. It is important to identify and treat TBI victims as early as possible. Tracking and monitoring TBI with neuroimaging technologies, including functional magnetic resonance imaging (fMRI), diffusion tensor imaging (DTI), positron emission tomography (PET), and high definition fiber tracking (HDFT) show increasing sensitivity and specificity. Classical electrophysiological monitoring, together with newly established brain-on-chip, cerebral microdialysis techniques, both benefit TBI. First generation molecular biomarkers, based on genomic and proteomic changes following TBI, have proven effective and economical. It is conceivable that TBI-specific biomarkers will be developed with the combination of systems biology and bioinformation strategies. Advances in treatment of TBI include stem cell-based and nanotechnology-based therapy, physical and pharmaceutical interventions and also new use in TBI for approved drugs which all present favorable promise in preventing and reversing TBI.

Autologous bone marrow mononuclear cells reduce therapeutic intensity for severe traumatic brain injury in children

OBJECTIVES

The devastating effect of traumatic brain injury is exacerbated by an acute secondary neuroinflammatory response, clinically manifest as elevated intracranial pressure due to cerebral edema. The treatment effect of cell-based therapies in the acute post-traumatic brain injury period has not been clinically studied although preclinical data demonstrate that bone marrow-derived mononuclear cell infusion down-regulates the inflammatory response. Our study evaluates whether pediatric traumatic brain injury patients receiving IV autologous bone marrow-derived mononuclear cells within 48 hours of injury experienced a reduction in therapeutic intensity directed toward managing elevated intracranial pressure relative to matched controls.

DESIGN

The study was a retrospective cohort design comparing pediatric patients in a phase I clinical trial treated with IV autologous bone marrow-derived mononuclear cells (n = 10) to a control group of age- and severity-matched children (n = 19).

SETTING

The study setting was at Children's Memorial Hermann Hospital, an American College of Surgeons Level 1 Pediatric Trauma Center and teaching hospital for the University of Texas Health Science Center at Houston from 2000 to 2008.

PATIENTS

Study patients were 5-14 years with postresuscitation Glasgow Coma Scale scores of 5-8.

INTERVENTIONS

The treatment group received 6 million autologous bone marrow-derived mononuclear cells/kg body weight IV within 48 hours of injury. The control group was treated in an identical fashion, per standard of care, guided by our traumatic brain injury management protocol, derived from American Association of Neurological Surgeons guidelines.

MEASUREMENTS AND MAIN RESULTS

The primary measure was the Pediatric Intensity Level of Therapy scale used to quantify treatment of elevated intracranial pressure. Secondary measures included the Pediatric Logistic Organ Dysfunction score and days of intracranial pressure monitoring as a surrogate for length of neurointensive care. A repeated-measure mixed model with marginal linear predictions identified a significant reduction in the Pediatric Intensity Level of Therapy score beginning at 24 hours posttreatment through week 1 (p < 0.05). This divergence was also reflected in the Pediatric Logistic Organ Dysfunction score following the first week. The duration of intracranial pressure monitoring was 8.2 ± 1.3 days in the treated group and 15.6 ± 3.5 days (p = 0.03) in the time-matched control group.

CONCLUSIONS

IV autologous bone marrow-derived mononuclear cell therapy is associated with lower treatment intensity required to manage intracranial pressure, associated severity of organ injury, and duration of neurointensive care following severe traumatic brain injury. This may corroborate preclinical data that autologous bone marrow-derived mononuclear cell therapy attenuates the effects of inflammation in the early post-traumatic brain injury period.