Journal of NeurotraumaVol. 41, No. 1-2 In MemoriamFree AccessA Tribute to Ronald L. HayesBruce Lyeth and Kevin K.W. WangBruce Lyeth and Kevin K.W. WangPublished Online:29 Dec 2023https://doi.org/10.1089/neu.2023.29141.rhAboutSectionsPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookXLinked InRedditEmail Our colleague and dear friend Ron Hayes died on November 13, 2023; a truly great loss to the world. We have received an outpouring of support and heartfelt sentiments, which we have compiled into this tribute. It is far too brief to capture everything, of course, and there will be many more to come.From Bruce Lyeth, UC-DavisRon stayed close to his hometown of Portsmouth, VA earning a BA in Classical Studies and Philosophy at the University of Richmond and a PhD in Physiological Psychology at VCU. During this academic journey he joined the Virginia Air National Guard earning his wings as a jet fighter pilot. In graduate school he studied endogenous opioids and nociception under David Mayer and continued in that field as a scientist at the NIH. Around 1980, the Division of Neurosurgery at MCV recruited Ron to lead the TBI labs where he and Japanese research fellow, Yoichi Katayama, performed seminal studies in traumatic unconsciousness and coma.I joined Ron's lab in 1983 at MCV as a VCU Psychology graduate student after fellow grad student Ed Dixon and my academic advisor, Bob Hamm, encouraged me to visit Ron's neurosurgery labs at nearby MCV. Ron was brilliant, insightful, energetic, sometimes impatient, but always warm-hearted. He always had incredible stories; tales of adventures traveling to scientific meetings – rarely did he travel without something unusual happening. He loved fast cars and bought an Acura only because it out-performed David Mayer's Toyota Celica!Ron confided to me that one of his favorite eras in science was with his "MCV crew" of Doug DeWitt, Larry Jenkins, Ed Dixon, Linda Phillips, and me on the 9th floor of Sanger Hall. Ron led our scientific inquiry into acetylcholine and glutamate receptor-mediated secondary injury cascades. This period was enriched by the many talented research fellows from Japan, Europe, South America, and China that passed through Ron's "kingdom." Thanks to Ron's leadership, they developed into productive scientists with many becoming leaders in the field of TBI. We learned so much from Ron about scientific method, writing, securing funding, and the utter joy of scientific discovery. Knowing Ron has made me a better scientist and a better person.Ron defined himself in many ways: philosopher, scientist, warrior in the battle against crippling brain injuries, and later described himself as " a closet philosopher and classicist. It may be unconventional training for a scientist, but it has served me very well."From Kevin K.W. Wang, Morehouse School of MedicineI got acquainted with Ron in about 1997 – while I was still at Parke-Davis Pharmaceutical. I fondly remembered that Ron and his then graduate student Rand Postmantur reached out to me to collaborate as we were all fascinated by the role of calpain in TBI. That led to two R01 grants in which I served as subaward PI at Parke-Davis. Such an arrangement in big pharma was practically unheard of - it was only possible because of Ron's optimism, thinking outside the box and his "why-not' attitude. That attitude also led to my joining him and Dr. Nancy Denslow at University of Florida and the McKnight Brain Institute. In 2001-2022, with input from my pharma industry background, a light bulb went off in our heads that there is really an unmet need for blood-based biomarker tests to help manage TBI patients. With the help of his friend and WRAIR contact Dr. Frank Tortella – we got the first ever DoD funded proteomic-based TBI biomarker discovery grant, which was followed by the NIH funded clinical TBI biomarker validation study in partnership with Baylor's Claudia Robertson and UF's Steve Robicsek. Pioneering biomarker discovery was hard, and for PhD scientists like Ron and me to conduct a clinical study was ten times harder; but Ron had a vision and the determination that to make a difference in the field of TBI, this was really where it needed to go. As they say, the rest is history, together we co-founded a spinoff company Banyan Biomarkers with the vision to develop the first-ever blood test for TBI and concussion. The Banyan brain injury test based on the tandem biomarkers UCH-L1/GFAP secured FDA clearance in February 2018 and completed a license with Abbott Laboratories that led to the marketing of their i-STAT TBI plasma test and the CE marking of Biomerieux's TBI test. I know that bringing a diagnostic test to the bedside from start to finish is truly a proud moment we both share – as he would say to me "We did it!" He has many other memorable quotes – such as academia researchers need to focus on "pubs and grants" and on writing an effective grant, just "keep it simple, stupid." Some my favorite memories of him at scientific conferences are that instead of sitting inside of conference rooms listening to talks, he seemed to spend more time outside of the rooms networking with others and forming new collaborations!Ron has been a great mentor to me and others. As Bruce mentioned, his classic language and philosophy training really showed in his well-articulated speeches. It was a privilege for me to know and to learn from him not only on how to be a good translational researcher but also to be a better communicator and to approach life and science with unwavering optimism.From Stephania Mondello, University of MessinaRon was a brilliant scientist, a leader, a role model, and a pioneer in the field of neurotrauma.From Alex Valadka, UT SouthwesternHe was always looking further down the road than most of us can see. He made a real impact.From Geoff Manley, UCSFSad news about a dear old friend, and someone who made a real difference in our field.From David Wright, Emory UniversityHe was indeed a treasured mentor for many of us and his vision lives on through us.From David Menon, Cambridge UniversityPlease pass on our sympathy to his family and let them know how highly he was respected by colleagues from outside the United States.From David Okonkwo, University of PittsburghRon had a huge influence on me going all the way to the back to beginning. I am deeply saddened by his passing and only wish I had a chance to share one more beer with him. That will now have to wait for a happy hour in the sky.I took this picture of him in Budapest many, many years ago. He loved it. He asked many times that I reforward it to him. I don't know why he loved it so much, but he did…it is a photo that captures his free spirit and embrace of life.From David Brody, Journal of NeurotraumaRon was amazingly kind to me when I was first starting out in the field. He made me feel truly welcome. Let's "pay it forward" in his memory and nurture the next generation. I think that's what he'd want.FiguresReferencesRelatedDetails Volume 41Issue 1-2Jan 2024 InformationCopyright 2024, Mary Ann Liebert, Inc., publishersTo cite this article:Bruce Lyeth and Kevin K.W. Wang.A Tribute to Ronald L. Hayes.Journal of Neurotrauma.Jan 2024.1-2.http://doi.org/10.1089/neu.2023.29141.rhPublished in Volume: 41 Issue 1-2: December 29, 2023Online Ahead of Print:December 14, 2023 PDF download

Background: Gamma electrical stimulation (GES) may reduce AD-specific pathology. Yet, the efficacy of electrical stimulation in animal models of AD is unknown, and prior research has not addressed intensity-dependent effects.Objective: The effect of GES on Aβ clearance and microglia modulation were assessed in 5xFAD mouse brain, as well as the behavioral performance of the animals in the Morris Water Maze.Methods and Results: One hour of epidural GES at 40Hz delivered over a month significantly 1) reduced Aβ42 load in the AD brain, 2) increased microglia cell counts, decreased cell body size, increased length of cellular processes of the Iba1+ cells, and 3) improved behavioral performance (learning & memory). All these effects were most pronounced when a higher stimulation current was applied.Conclusion: The efficacy of GES on the reduction of AD pathology and the intensity-dependent feature provides guidance for the development of this promising therapeutic approach.

Our previous studies demonstrated that traumatic brain injury (TBI) and ventricular administration of thrombin caused hippocampal neuron loss and cognitive dysfunction via activation of Src family kinases (SFKs). Based on SFK localization in brain, we hypothesized SFK subtypes Fyn and c-Src, as well as SFK downstream molecule Rho-associated protein kinase (ROCK), contribute to cell death and cognitive dysfunction after TBI. We administered nanoparticle wrapped small interfering RNA (siRNA)-Fyn and siRNA-c-Src, or ROCK inhibitor Y-27632 to adult rats subjected to moderate lateral fluid percussion (LFP)-induced TBI. Spatial memory function was assessed from 12 to 16 days, and NeuN stained hippocampal neurons were assessed 16 days after TBI. The combination of siRNA-Fyn and siRNA-c-Src, but neither alone, prevented hippocampal neuron loss and spatial memory deficits after TBI. The ROCK inhibitor Y-27632 also prevented hippocampal neuronal loss and spatial memory deficits after TBI. The data suggest that the combined actions of three kinases (Fyn, c-Src, ROCK) mediate hippocampal neuronal cell death and spatial memory deficits produced by LFP-TBI, and that inhibiting this pathway prevents the TBI-induced cell death and memory deficits.

Cerebral blood flow (CBF) is essential for brain function, and CBF-related signals can inform us about brain activity. Yet currently, high-end medical instrumentation is needed to perform a CBF measurement in adult humans. Here, we describe functional interferometric diffusing wave spectroscopy (fiDWS), which introduces and collects near-infrared light via the scalp, using inexpensive detector arrays to rapidly monitor coherent light fluctuations that encode brain blood flow index (BFI), a surrogate for CBF. Compared to other functional optical approaches, fiDWS measures BFI faster and deeper while also providing continuous wave absorption signals. Achieving clear pulsatile BFI waveforms at source-collector separations of 3.5 cm, we confirm that optical BFI, not absorption, shows a graded hypercapnic response consistent with human cerebrovascular physiology, and that BFI has a better contrast-to-noise ratio than absorption during brain activation. By providing high-throughput measurements of optical BFI at low cost, fiDWS will expand access to CBF.

Aneurysmal intraventricular hemorrhage (IVH) survivors may recover with significant deficits in learning and memory. The goal of this study was to investigate the mechanism of memory decline after intraventricular aneurysm rupture. We developed an aneurysmal IVH rat model by injecting autologous, arterial blood over the period of two minutes into the right lateral ventricle. We also evaluated the effects of a volume-matched artificial cerebrospinal fluid (CSF) control, thrombin and the mode of delivery (pulsed hand injection versus continuous pump infusion). We performed magnetic resonance brain imaging after 1 and 5 weeks to evaluate for hydrocephalus and histological analysis of the dentate gyrus after 6 weeks. Only animals which underwent a whole blood pulsed hand injection had a spatial memory acquisition and retention deficit 5 weeks later. These animals had larger ventricles at 1 and 5 weeks than animals which underwent a continuous pump infusion of whole blood. We did not find a decline in dentate gyrus granule cell neurons or an impairment in dentate gyrus neurogenesis or differentiation 6 weeks after IVH. Rapid injections of blood or volume resulted in microglial activation in the dentate gyrus. In conclusion, our results point to mechanical injury as the predominant mechanism of memory decline after intraventricular aneurysmal rupture. However, volume-matched pulsed injections of artificial CSF did not create a spatial memory deficit at 5 weeks. Therefore, whole blood itself must play a role in the mechanism. Further research is required to evaluate whether the viscosity of blood causes additional mechanical disruption and hydrocephalus through a primary injury mechanism or whether the toxicity of blood causes a secondary injury mechanism that leads to the observed spatial memory deficit after 5 weeks.

Millions suffer a traumatic brain injury (TBI) each year wherein the outcomes associated with injury can vary greatly between individuals. This study postulates that variations in each biomechanical parameter of a head trauma lead to differences in histological and behavioral outcome measures that should be considered collectively in assessing injury. While trauma severity typically scales with the magnitude of injury, much less is known about the effects of rate and duration of the mechanical insult. In this study, a newly developed voice-coil fluid percussion injury system was used to investigate the effects of injury rate and fluid percussion impulse on a collection of post-injury outcomes in male rats. Collectively the data suggest a potential shift in the specificity and progression of neuronal injury and function rather than a general scaling of injury severity. While a faster, shorter fluid percussion first presents as a mild TBI, neuronal loss and some behavioral tasks were similar among the slower and faster fluid percussion injuries. This study concludes that the sequelae of neuronal degeneration and behavioral outcomes are related to the complete temporal profile of the fluid percussion and do not scale only with peak pressure.

Background Neurogenesis is significantly impaired in the brains of both human patients and experimental animal models of Alzheimer’s disease (AD). Although deep brain stimulation promotes neurogenesis, it is an invasive technique that may damage neural circuitry along the path of the electrode. To circumvent this problem, we assessed whether intracranial electrical stimulation to the brain affects neurogenesis in a mouse model of Alzheimer’s disease (5xFAD). Methods and results We used Ki67, Nestin, and doublecortin (DCX) as markers and determined that neurogenesis in both the subventricular zone (SVZ) and hippocampus were significantly reduced in the brains of 4-month-old 5xFAD mice. Guided by a finite element method (FEM) computer simulation to approximately estimate current and electric field in the mouse brain, electrodes were positioned on the skull that were likely to deliver stimulation to the SVZ and hippocampus. After a 4-week program of 40-Hz intracranial alternating current stimulation (iACS), neurogenesis indicated by expression of Ki67, Nestin, and DCX in both the SVZ and hippocampus were significantly increased compared to 5xFAD mice who received sham stimulation. The magnitude of neurogenesis was close to the wild-type (WT) age-matched unmanipulated controls. Conclusion Our results suggest that iACS is a promising, less invasive technique capable of effectively stimulating the SVZ and hippocampus regions in the mouse brain. Importantly, iACS can significantly boost neurogenesis in the brain and offers a potential treatment for AD.

Journal of NeurotraumaVol. 35, No. 1 CommentaryReflections on 35 Years of Journal of NeurotraumaPublished Online:1 Jan 2018https://doi.org/10.1089/neu.2018.29016.commentaryAboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View articleFiguresReferencesRelatedDetails Volume 35Issue 1Jan 2018 InformationCopyright 2018, Mary Ann Liebert, Inc.To cite this article:Reflections on 35 Years of Journal of Neurotrauma.Journal of Neurotrauma.Jan 2018.4-16.http://doi.org/10.1089/neu.2018.29016.commentaryPublished in Volume: 35 Issue 1: January 1, 2018PDF download

Transcranial electrical stimulation (tES) can be an effective non-invasive neuromodulation procedure. Unfortunately, the considerable variation in reported treatment outcomes, both within and between studies, has made the procedure unreliable for many applications. To determine if individual differences in cranium morphology and tissue conductivity can account for some of this variation, the electrical density at two cortical locations (temporal and frontal) directly under scalp electrodes was modeled using a validated MRI modeling procedure in 23 subjects (12 males and 11 females). Three different electrode configurations (non-cephalic, bi-cranial, and ring) commonly used in tES were modeled at three current intensities (0.5, 1.0, and 2.0 mA). The aims were to assess the effects of configuration and current intensity on relative current received at a cortical brain target directly under the stimulating electrode and to characterize individual variation. The different electrode configurations resulted in up to a ninefold difference in mean current densities delivered to the brains. The ring configuration delivered the least current and the non-cephalic the most. Female subjects showed much less current to the brain than male subjects. Individual differences in the current received and differences in electrode configurations may account for significant variability in current delivered and, thus, potentially a significant portion of reported variation in clinical outcomes at two commonly targeted regions of the brain.

Based upon our previous findings that microRNA-122 (miR-122) was decreased in peripheral blood of both humans and rats after ischemic stroke, we hypothesized that elevating miR-122 in blood might improve outcomes after ischemic stroke. Using the in vivo polyethylene glycol 2000 (PEG)-liposome based miRNA transfection system and the rat middle cerebral artery occlusion (MCAO) model, we recently demonstrated that intravenous (i.v.) miR-122 mimic, given immediately after MCAO, elevated miR-122 in peripheral blood, prevented neurological impairments, and reduced brain infarction volume up to 93% after MCAO in rats. Using Taqman PCR based assays, we demonstrate fourteen direct miR-122 target genes (e.g. Nos2, Vcam1, Clic4, Ucp2, Dlg2, and others) were decreased in blood leukocytes following miR-122 mimic treatment after MCAO in rats. Focusing on ONE miR-122 target gene (Nos2), we demonstrated that miR-122 binds to the complementary sequence within three prime untranslated regions (3’UTRs) of Nos2 using luciferase reporter assay, and that miR-122 mimic decreases Nos2 expression in brain microvascular endothelial cells (BMVECs) after MCAO in rats. These results show that Nos2 is decreased in leukocytes and BMVECs following miR-122 mimic treatment after MCAO, which likely contributes to miR-122 induced protection after MCAO in rats. Acknowledgements: This study was supported by NIH grants R01NS089901 (DZL) and NS054652 (FRS). There were no conflicts of interest.

Limited migration of neural stem cells in adult brain is a roadblock for the use of stem cell therapies to treat brain diseases and injuries. Here, we report a strategy that mobilizesand guides migrationof stem cells in the brain in vivo . We developed a safe stimulation paradigm to deliver directional currents in the brain. Tracking cells expressing GFP demonstrated electrical mobilization and guidance of migration of human neural stem cells, even against co-existing intrinsic cues in the rostral migration stream. Transplanted cells were observed at 3 weeks and 4 months after stimulation in areas guided by the stimulation currents, and with indications of differentiation. Electrical stimulation thus may provide a potential approach to facilitate brain stem cell therapies.

Traumatic brain injury (TBI) is a leading cause of death and disability in the United States, and, to date, no pharmacological agents are known to improve neurological outcome following injury. TBI is associated with a severity-dependent accumulation of intracellular calcium ([Ca2+]i) lasting hours-to-days postinjury and driving apoptotic and necrotic cell death. Pathological accumulation of calcium can also lead to breakdown of structural proteins and changes in gene expression resulting in long-term dysfunction of surviving cells. In in vitro models of TBI, L- and N-type voltage-gated calcium channel (VGCC) blockers reduced [Ca2+]i accumulation and glutamate release resulting in reduced cell death. In rodent models of TBI, administration of VGCC blockers reduced cell death and improved spatial learning and motor function. Based on these data, there is a clear role of VGCC in postinjury pathophysiology, and manipulation of these channels has the potential to improve neurological outcome following injury.