The pathologic process of chronic phase traumatic brain injury is associated with spreading inflammation, cell death, and neural dysfunction. It is thought that sequestration of inflammatory mediators can facilitate recovery and promote an environment that fosters cellular regeneration. Studies have targeted post-traumatic brain injury inflammation with the use of pharmacotherapy and cell therapy. These therapeutic options are aimed at reducing the edematous and neurodegenerative inflammation that have been associated with compromising the integrity of the blood-brain barrier. Although studies have yielded positive results from anti-inflammatory pharmacotherapy and cell therapy individually, emerging research has begun to target inflammation using combination therapy. The joint use of anti-inflammatory drugs alongside stem cell transplantation may provide better clinical outcomes for traumatic brain injury patients. Despite the promising results in this field of research, it is important to note that most of the studies mentioned in this review have completed their studies using animal models. Translation of this research into a clinical setting will require additional laboratory experiments and larger preclinical trials.

Several lines of laboratory investigations reporting solid safety profiles and robust efficacy readouts of stem cells in clinically relevant animal models have advanced stem cell transplantation as an experimental therapy for stroke. Unfortunately, translating laboratory findings into effective clinical trials entails rigorous regulatory examinations, which posed a major challenge in the application of stem cells to patients. As a consequence of this slow pace of clinical entry, and a media-propagated hype narrating stem cells as a “magic bullet”, a dangerous market has been created for unregulated stem cell clinics. These clinics are often guilty of misleading patients and delivering low-quality, even harmful, treatments. Additionally, these medical tourism-purported clinical procedures, which have been performed even in the US, are likely to negatively impact on the true science and clinical value of stem cells. For the full potential of stem cell therapies to be realized, these pressing public misconceptions and regulatory clinical concerns must be addressed. Here, we provide the scientific evidence supporting the safe and effective conduct of stem cells. Arguably, relying on such evidence-based science to dictate the translation of stem cells from the laboratory to the clinic should allow an objective assessment of the risks and the rewards, and the delineation of the hype from hope of this experimental stroke therapy.

The opioid system has been elucidated as a potential target for therapy in a variety of neurological disorders including stroke. Delta opioid receptors have been revealed to pose an especially compelling biological function for new neuroprotective therapies. Two distinct therapeutic mechanisms have been characterized for delta opioid receptors, namely, these receptors aid in maintaining ionic homeostasis and initiate endogenous neuroprotective pathways. Specific agonists of delta opioid receptors, such as (D-Ala2, D-Leu5) enkephalin (DADLE), have displayed the ability to promote neuronal survival and mitigate apoptotic pathways. These findings have led to a significant amount of research on this molecule's potential as a neurotherapeutic. At the forefront of these efforts has been investigation into DADLE's ability to protect neurons and glial cells following ischemia. Additionally, current research is attempting to reveal the dynamic neuroprotective mechanisms that mediate DADLE's therapeutic benefits. This review article discusses the scientific evidence supporting the use of delta opioid family of receptors and ligands as a promising target for therapeutic intervention in neurological disorders, with emphasis on stroke.

Research of the opioid system and its composite receptors and ligands has revealed its promise as a potential therapy for neurodegenerative diseases such as stroke and Parkinson's Disease. In particular, delta opioid receptors (DORs) have been elucidated as a therapeutically distinguished subset of opioid receptors and a compelling target for novel intervention techniques. Research is progressively shedding light on the underlying mechanism of DORs and has revealed two mechanisms of DOR neuroprotection; DORs function to maintain ionic homeostasis and also to trigger endogenous neuroprotective pathways. Delta opioid agonists such as (D-Ala2, D-Leu5) enkephalin (DADLE) have been shown to promote neuronal survival and decrease apoptosis, resulting in a substantial amount of research for its application as a neurological therapeutic. Most notably, DADLE has demonstrated significant potential to reduce cell death following ischemic events. Current research is working to reveal the complex mechanisms of DADLE's neuroprotective properties. Ultimately, our knowledge of the DOR receptors and agonists has made the opioid system a promising target for therapeutic intervention in many neurological disorders.