Often called the silent epidemic, traumatic brain injuries (TBIs) afflict approximately 1.7 million Americans annually. More than 52,000 are killed, and 275,000 are hospitalized.1 Most are left in various states of disability—from almost-full recovery, to mild symptoms but able to function with some or moderate disability, to severe disability requiring around-the-clock intensive care and support. The annual direct and indirect cost of TBIs, such as lost work time or reduced productivity, have been estimated at more than $60 billion, and there may be more than six million TBI survivors in society with some disability.2
Over the past decade, TBI has come to the fore as tens of thousands of wounded soldiers return home from the Middle East suffering hidden or visible TBIs and trauma caused by blast injuries from improvised roadside explosions.3 What is called post-traumatic stress disorder may actually be the long-term after-effects of TBI.
Due to the economic and social costs of TBI, a significant ongoing effort is being made to develop and apply emerging new clinical and preclinical pharmaceuticals that hold the potential in post-injury medical treatment to mitigate the cascading additional brain damage that occurs during the critical secondary phase in TBIs. Among these is an interesting pharmaceutical compound called cyclosporine (also known as cyclosporin-A, or CsA) that has been found to have significant neuroprotective capabilities and the ability to moderate the resulting damage and long-term disability in TBI.4,5,6,7
Preclinical mouse model studies show an 80% reduction in neural damage through the application of this pharmaceutical.8, 9 More than 17 years in development for neuroprotection, CsA is working its way toward approval as a treatment to greatly ameliorate the effects of TBI in humans.
There are two stages in traumatic brain injuries. The first stage occurs at the time of injury, for example due to a gunshot, blast, fall, or hit. This initial stage could be either a closed-head or open-wound injury, and medical emergency personnel focus on treating the wound or injury and, importantly, stabilizing the patient’s vital signs.
The secondary stage of damage to the brain takes place after the initial insult, as the injury continues to ripen and worsen in the hours and days after the initial trauma. This is when the doctor says, “Now we just wait and see,” as there’s nothing more that medicine can do. In this secondary stage, the trauma to the brain triggers a series of cascading intracellular biochemical reactions that end up causing severe demise of brain cells, brain damage and expanded disability. If this secondary stage can be mitigated, the eventual damage and disability can be greatly reduced, enabling the victim to get closer to full recovery.
Some of the secondary-stage mechanisms believed by researchers to be involved in brain-cell death after TBI include uncontrolled release of signalling molecules (neurotransmitters), cellular calcium overload, inflammation, energy failure, oxidative damage, and the overactivation of enzymes such as calpains and caspases.10
All of these are believed to create the intracellular and extracellular conditions that lead to the destruction of millions of additional brain cells, and the damage and disability that result. Many of these are being targeted by a variety of pharmaceutical compounds and medical treatments (such as forcing oxygen into the brain through the use of hyperbaric chambers) that are in various stages of clinical development.11 By targeting the protection of mitochondria inside brain cells, cyclosporine is perhaps the most promising of these.
Research confirms that mitochondria, as the cellular energy (ATP) producers inside the brain cells, play a pivotal role in neuronal cell death or survival, and that mitochondrial dysfunction is considered an early event in brain injuries that causes neuronal cell death. The uncontrolled release of signalling molecules with resulting overstimulation/stress of brain cells and accumulation of high levels of intracellular calcium may be the initial mechanism that leads to neuronal cell death.12
How does this affect brain cells? Increases in calcium lead to its rapid uptake into the mitochondria (which act as cellular sinks for calcium). However, the excessive transport and uptake of calcium will negatively impact mitochondrial energy production, as the driving force for ATP production and calcium transport both rely on the “proton motive force” (the proton gradient created over the mitochondrial inner membrane by the respiratory chain). Further, excessive calcium uptake by mitochondria, in combination with energy failure, leads to the formation of protein channels (pores) in the inner membrane—the induction of the so-called mitochondrial permeability transition (mPT).
The increased permeability of the inner membrane caused by the mPT pores immediately collapses mitochondrial function and structure (when the pores are opened, the osmotically active inner compartment (matrix) of the mitochondria will attract water and the mitochondria will swell and pop like balloons). In addition to causing the cessation of energy production, upon induction of the mPT the stored calcium and harmful proteins will then be released from mitochondria, resulting in an avalanche of further mitochondrial collapse, cellular energy depletion, and subsequent cell death. When brain-cell death is repeated millions of times during the cascading biochemical imbalances that characterize the secondary phase, the extent of brain damage and eventual disability is greatly increased.13
Protecting the mitochondria by targeting the mPT is a viable neuroprotective approach that has emerged in the last decade. Published research has found that the protein cyclophilin D is an essential component in opening the mPT pores,14 and that cyclosporine binds to cyclophilin D and inhibits the induction of mPT.15 The result is that mitochondria can absorb much more calcium without collapsing, allowing them to survive. As mitochondria survive to produce energy for the brain cell, fewer brain cells die during the secondary stage. This is the core battleground in the war against TBIs.
Cyclosporine was discovered in 1969 when it was first isolated from the fungus Tolypcladium inflatum in Norway by researchers working for Sandoz (now Novartis). Its impressive immunosuppressive properties led it to become a pharmaceutical to prevent tissue rejection in organ transplant patients. It has been in use for immunosuppressive applications since the early 1980s as a commercially successful Novartis product called Sandimmune.16
CsA’s ability to protect the mitochondria in the brain by binding to cyclophilin D and preventing the induction of the mPT was later discovered in 1993–1994, a period during which medical researcher Eskil Elmérand his Japanese colleague Hiroyuki Uchino working in Sweden were conducting experiments in cell transplantation. An unintended finding was that CsA was strongly neuroprotective when it crossed the blood–brain barrier.17 The startling discovery became the starting point for basic research and patent applications in this promising new avenue of neuroprotection that have continued and expanded to the present day.
The fundamental research mapping out CsA’s extensive neuroprotective capabilities has been running continuously since 1993, and many international and independent research teams have since conducted and published numerous studies confirming that CsA is a powerful nerve-cell protector in TBI, stroke and brain damage associated with cardiac arrest. Advanced studies also show that CsA is useful in protecting mitochondria in heart tissue facing reperfusion injury during heart attacks (see sidebar).18
Together with U.S. neurosurgeon Dr. Marcus Keep, Dr. Elmérand his colleagues formed a company with the aim of commercializing and patenting their work of developing cyclosporine-based products for acute conditions and diseases affecting the brain. In 1999, the U.S. patent was approved and, in 2000, their CsA product name NeuroSTAT was registered. Later, the patent portfolio around CsA’s impact on the CNS, cardiac and other areas was expanded greatly under their company NeuroVive Pharmaceutical AB (Sweden).
Today, NeuroVive’s NeuroSTAT version of cyclosporine is a fully developed product. An important advancement in NeuroSTAT is that its formulation is made using a patented non-allergenic lipid emulsion to keep CsA as a lipophilic drug in solution.
It’s been almost two decades since Eskil Elmérand his colleagues first discovered cyclosporine’s neuroprotective capabilities and there is still some way to go. However, CsA’s promise as a TBI pharmaceutical continues to make progress. Full commercialization is now in sight.
In 2010, NeuroSTAT received orphan drug status from both the U.S. FDA and in Europe for the treatment of moderate and severe TBI. In March 2011, the company announced it would be working with the European Brain Injury Consortium to conduct a phase II/III adaptive study on NeuroSTAT.19 These clinical trials should provide the basis for the registration of NeuroSTAT in Europe, and possibly the U.S. and elsewhere. U.S.-based clinical trials are also being planned, and NeuroVive is seeking partnering organizations in China for similar trials.
Of course, the challenges in such trials, where many TBI drugs have failed in the past, are to translate promising animal study research results into clinical benefits in humans, and be able to recruit sufficient patients within a reasonable time frame. What’s most exciting and unique for NeuroSTAT is that cyclosporine has already been shown in a small-group human study published in the New England Journal of Medicine (NEJM) in 2008 to deliver a 40 percent reduction in heart damage from reperfusion injury in myocardial infarction.20
Since the mechanism of cyclosporine’s ability to protect mitochondria in acute injury is the same in TBI as it is in reperfusion injury, NeuroSTAT’s future prospect as a pharmaceutical to treat moderate to severe TBI appears exceptionally promising.
At the same time, an NEJM editorial called for follow-up studies to fully determine cyclosporine’s capacity to reduce reperfusion injury.21 In April 2011, a 1,000-patient investigator-initiated phase III study in Europe enrolled its first subject; it is expected to be completed in 2013. The study is using NeuroVive’s CicloMulsion (the trade name of NeuroSTAT for the reperfusion injury market) and will conclude with 12 months of follow-up with all patients.22
Assuming all goes according to plan with its clinical studies, cyclosporine’s early promise from its serendipitous discovery as a neuroprotectant in the 1990s could be fulfilled within the next two to five years. Then neurologists and neurosurgeons worldwide will finally be able to trumpet that they have an exciting new weapon in their war against the silent epidemic and onslaught of traumatic brain injuries.
There are a number of TBI pharmaceuticals in a variety of stages of development. The most promising of these approaches are “multipotential,” targeting at least two or more secondary-stage injury mechanisms, including excitotoxicity, apoptosis, inflammation, edema, blood–brain barrier disruption, oxidative stress, mitochondrial disruption, calpain activation, and cathepsin activation.1
The value of multipotential agents is that they have potential to modulate one or more of these multiple secondary injury factors, providing a great chance of achieving clinical value. Previously, more than 30 phase III clinical studies for single-factor targeted TBI pharmaceuticals failed to find significance. Multipotentials may have a greater chance of delivering a successful therapeutic result for TBI patients and ultimately recouping the cost of development and trials.2
Promising pharmacological multipotential agents fall under two categories: those that have been studied clinically and those that constitute emerging preclinical strategies. Clinically studied pharmaceuticals include the statins (targeting excitotoxicity, apoptosis, inflammation, edema), progesterone (excitotoxicity, apoptosis, inflammation, edema, oxidative stress), and cyclosporine (mitochondrial disruption, calpain activation, apoptosis, oxidative stress).3
Emerging multipotential neuroprotective agents showing promise in preclinical studies include diketopiperazines (apoptosis, calpain activation, cathepsin activation, inflammation), substance P antagonists (inflammation, blood–brain barrier, edema), SUR1-regulated NC channel inhibitors (apoptosis, edema, secondary hemorrhage, inflammation), cell cycle inhibitors (apoptosis, inflammation), and PARP inhibitors (apoptosis, inflammation).4—SC
1.Loane J, Faden A. Neuroprotection for traumatic brain injury: translational challenges and emerging therapeutic strategies. Trends in Pharmacological Sciences, 2010 Dec 31;(12):596–604.
Mitochondria are present, and produce effective energy, in almost all cells in the body. It turns out that mitochondrial collapse may be associated with a variety of acute injuries, such as myocardial infarctions and also chronic diseases such as ALS, MS and other neurological disorders. In myocardial infarctions, reperfusion of the blocked artery can cause reperfusion injury, and extra damage and disability to the heart muscle, as well as increased mortality. Mitochondrial protection in heart muscle tissue is one answer to moderating the long-term impact of heart attacks on health and lifestyle.
Every year, an estimated 500,000 people in the United States have a myocardial infarction. Infarct size is a major determinant of mortality. During myocardial reperfusion, the abruptness of the reperfusion can cause additional damage—a phenomenon called myocardial reperfusion injury. Studies indicate that this form of injury can account for up to 50% of the final size of the infarct.1 Focusing on reducing the additional infarct resulting from reperfusion would protect heart muscle and allow the patient to live longer and in better health after the initial attack.
Interestingly, a number of proposed interventions, e.g., ischemic post-conditioning, have been claimed to mediate their cardioprotective actions by acting on the opening of the mitochondrial permeability transition pore (which is directly inhibited by cyclosporine). CsA has been studied for its cardioprotective capabilities and found to be a potentially significant pharmaceutical for ameliorating long-term damage from heart attacks.
A small proof-of-concept clinical study by Piot and his colleagues, published in the New England Journal of Medicine in 2008, found that the administration of CsA with the aim of inhibiting the induction of the mPT was associated with a 40% reduction in infarct size.2 An editorial in the Journal called for large, multicenter studies to determine if this new treatment option can positively influence clinical outcomes. In addition, targeting the mPT “may also offer protection in other clinical contexts, such as stroke, cardiac surgery, and organ transplantation.”3
Following that lead, in April 2011, a European investigator-initiated multicentre phase III study of NeuroVive’s cyclosporine-based cardioprotection pharmaceutical (called CicloMulsion) in myocardial infarctions enrolled the first of 1,000 patients. The last patients are expected to be enrolled in 2013, after which there will be 12 months of follow-up.4 —SC
1.Hausenloy D, Yellon D. Time to take myocardial perfusion injury seriously. The New England Journal of Medicine. Comment. 2008; 359 (5): 518-520.
2. Piot C, Croiselle P, Staat P, et al. Effects of cyclosporine on reperfusion injury in acute myocardial infarction. The New England Journal of Medicine. 2008; 359 (5): 473-481.
3. Hausenloy D, Ibid.
It is difficult for many drugs, including cyclosporine, to cross the blood–brain barrier.1 However, traumatic brain injury often causes the blood–brain barrier to open and permit cyclosporine to reach those areas of the brain in which the need is greatest. However, in other conditions, such as stroke, the barrier does not open in the same way as in TBI. NeuroVive is conducting research to identify variants of cyclosporine that can penetrate the blood–brain barrier, with a view to being able to provide the brain with neuronal protection under conditions other than TBI. NeuroVive is also evaluating the possibility of administering cyclosporine directly to the brain fluid (e.g., through lumbar puncture).
In preclinical pilot studies, NeuroVive’s researchers demonstrated, in collaboration with scientists in the army, that cyclosporine crosses the blood–brain barrier in prolonged seizures due to hyperactivity in the brain. In cases of stroke, scheduled cardiac surgery, and cardiac arrest, the brain cannot yet be reached satisfactorily through intravenous therapy, since a method of increasing the passage of cyclosporine through the blood–brain barrier in these conditions has not yet been found. To this effect, in 2010 NeuroVive and the Dutch brain drug delivery company to-BBB entered into a joint program to develop therapies for stroke and other acute neurodegenerative diseases by combining their technologies.
NeuroVive is also conducting research to develop advanced cyclosporins, formulations, new chemical compounds, or small molecules that allow improved or free passage across the blood–brain barrier. The company is also researching and developing cyclosporine analogue molecules without immunosuppressive effects that can be combined with new formulations and technologies.2 —SC
1.Osherovich, L. Beating the brain’s bouncer. Science-Business eXchange. 2009; 2 (19): 1-4.
2. Email interview with NeuroVive CSO Eskil Elmér.
Sometime in the 1990s, an anonymous 14-year-old liver transplant patient from Germany—regularly using cyclosporine to prevent tissue rejection—was hit by a car and suffered head injuries. By chance, an anaesthesiologist was at the scene when the accident occurred. He immediately examined the boy and suspected severe brain damage, later confirmed by an early Glasgow Coma Scale (GCS) score of three.
Although the worst was feared—children under 14 with a GCS below eight have a 28% mortality rate or significant brain disability if they do survive—the patient not only survived but proceeded to make an amazing recovery. He was discharged from hospital five weeks later and was able to return to school after two months. He recovered unexpectedly well and is now an adult with a young son. The neuroprotective properties of cyclosporine were suspected in the recovery and the case was reported in a detailed case study published in the Journal of Neurosurgical Anesthesiology in 1998.1
The study concluded: “We conclude that neuroprotective properties of cyclosporine A [sic] may have been involved in the good recovery after severe brain injury in this 14-year-old patient.”—SC
1.Gogarten W, Van Aken H, Moskopp D, et al. A case of severe cerebral trauma in a patient under chronic treatment with cyclosporine A [sic]. Journal of Neurosurgical Anesthesiology. 1998 10 (2): 101-105.
A traumatic brain injury is defined as a blow or jolt to the head or a penetrating head injury that disrupts the function of the brain. Not all such blows or jolts to the head result in a TBI. The severity of TBIs may range from “mild”—a brief change in consciousness—to “severe”—featuring an extended period of amnesia or unconsciousness. A TBI can result in problems in independent function, either short- or long-term.
There are literally millions of Americans who now have a long-term need for help to perform their daily activities as a result of suffering a TBI. It’s been estimated there may be up to six million survivors of TBI. Statistics on the full extent of TBI are not known, however, as the number of people with TBI not seen in an emergency department and/or who have received no formal care cannot be determined.
The leading causes of TBI include falls, car crashes, hitting or being hit in sports, and physical assault. In war zones, blasts from roadside improvised explosive devices (IEDs) and other explosions are a leading cause of TBIs for soldiers. Males are 1.5 times as likely as females to suffer a TBI, and the two age groups at highest risk are 0–4 years and teenagers age 15–19. African Americans have the highest death rates from TBI, and TBI is the fourth-leading cause of death for males under age 45.1
More recently, the Iraq and Afghanistan wars have brought the issue to the attention of the public and Congress, as advances in combat protection and helmets have allowed soldiers to survive blasts that previously would have killed them. Soldiers are returning home with TBI, but there is little that can be done for them post-injury. It’s been estimated that some 200,000 returning soldiers have varying degrees of TBI, ranging from mild to severe. Symptoms include depression, an inability to concentrate, moodiness, and frustration as the TBI sufferer struggles to complete formerly routine tasks. Moreover, much anti-social behaviour exhibited in society may be related to diagnosed or undiagnosed traumatic brain injuries sustained in battle, on sports fields, on the streets, or around the home.—SC
1.Statistics on Traumatic Brain Injury. Source: Centers for Disease Control. www.cdc.gov/traumaticbraininjury/statistics.html
Steve Campbell is a writer and communications consultant in Vancouver, B.C., who writes for and about pharmaceutical and scientific research, products and companies. He can be reached at email@example.com.
1. Statistics on Traumatic Brain Injury. Source: Centers for Disease Control. www.cdc.gov/traumaticbraininjury/statistics.html
3. Hoge C, McGurk D, Thomas J, et al. Mild traumatic brain injury in U.S. soldiers returning from Iraq. The New England Journal of Medicine. 2008; 358 (5): 453-463.
4. Sullivan P, Sebastian A, Hall E. Therapeutic window analysis of the neuroprotective effects of cyclosporine A after traumatic brain injury. Journal of Neurotrauma 2011 Feb;28:311-318.
5. Hansson, MJ, Morota S, Chen L et al. Cyclophilin D-sensitive mitochondrial permeability transition in adult human brain and liver mitochondria. Journal of Neurotrauma 2011 Jan;28(1):143-53.
6. Mazzeo AT, Brophy GM, Gilman CB, Alves OL, Robles JR, Hayes RL, Povlishock JT, Bullock MR. Safety and tolerability of cyclosporin a in severe traumatic brain injury patients: results from a prospective randomized trial. Journal of Neurotrauma. 2009; Dec;26(12):2195-2206.
7. Cook AM, Whitlow J, Hatton J, Young B. Cyclosporine A for neuroprotection: establishing dosing guidelines for safe and effective use. Expert Opinion on Drug Safety. 2009 Jul;8(4):411-419.
8. Sullivan P, Sebastian A, Hall E. Therapeutic window analysis of the neuroprotective effects of cyclosporine A after traumatic brain injury. Journal of Neurotrauma 2011 Feb; 28 (2) 311-318.
9. Sullivan P, Thompson M, Scheff W. Continuous infusion of cyclosporin A post injury significantly ameliorates cortical damage following traumatic brain injury. Experimental Neurology 2000 Feb; (161: 631-637.
10. Loane J, Faden A. Neuroprotection for traumatic brain injury: translational challenges and emerging therapeutic strategies. Trends in Pharmacological Sciences 2010 Dec. 31;(12):596-604.
12. Mazzeo AT, Beat A, Singh A, Bullock MR. The role of mitochondrial transition pore, and its modulation, in traumatic brain injury and delayed neurodegeneration after TBI. Exp Neurol. Review. 2009 Aug; 218(2):363-730. Epub 2009 May 27.
14. Schinzel A et al, Cyclophilin D is a component of mitochondrial permeability transition and mediates neuronal cell death after focal cerebral ischemia. Proceedings of the National Academy of Sciences. 2005 102: (34) 12005-12010.
15. Waldmeier PC, Zimmerman K, Qian T, Tintelnot-Blomley M, Lemasters, J, Cyclophilin D as a drug target. Current Medicinal Chemistry 2003 10: (16) 1485-1506.
17. Uchino H, ElmérE, Uchino K, Lindvall O, Siesjo BK. Cyclosporin A dramatically ameliorates CA1 hippocampal damage following transient forebrain ischaemia in the rat.Acta Physiologica Scandinavica. 1995 Dec;155(4):469-471.
18. Piot C, Croiselle P, Staat P, et al. Effects of cyclosporine on reperfusion injury in acute myocardial infarction. The New England Journal of Medicine. 2008; 359 (5): 473-481.
20. Piot C, Croiselle P, Staat P, et al. Effects of cyclosporine on reperfusion injury in acute myocardial infarction. The New England Journal of Medicine. 2008; 359 (5): 473-481.
21.Hausenloy D, Yellon D. Time to take myocardial perfusion injury seriously. The New England Journal of Medicine. Comment. 2008; 359 (5): 518-520.
Used with permission by Steve Campbell and Pharmaceutical Formulation & Quality magazine. The article was first published in Pharmaceutical Formulation & Quality magazine, August/September 2010. www.pharmaquality.com. Article link http://www.nxtbook.com/nxtbooks/wiley/pfq_20110809/#/16.