1. Penn Center for Brain Injury and Repair Known knowns and known unknowns:A “disconnect” – Is there Axonal Pathology Following Blast TBI? Douglas H. Smith, MD Department of Neurosurgery and Penn’s Center for Brain Injury and Repair University of Pennsylvania

2. No personal attacks are intended! 3.3 lb. Human Brain 1 lb. Boxing Glove

3. It is generally believed that diffuse axonal injury is the primary neuropathologicalsequelae of non-blast mTBI/ concussion. Is this true in mild blast TBI as well?

4. Contact Loading Inertial Loading 1o BLAST? Diffuse Axonal Injury (DAI)

5. Diffuse Axonal Injury Inertial loading

6. DAI: Diagnosis of exclusion T2 CT A “disconnection” syndrome

7. Evolution of Axonal Pathology Periodic varicosities Terminal bulb

8. Axonal Pathologies Post-trauma

9. What is DAI? “A diffuse degeneration of the white matter of the cerebral hemispheres.” “there is much evidence in favour of mechanical damage as the chief cause for the lesions” Strich, SJ:Lesions in the cerebral hemispheres after blunt head injury. J ClinPatholSuppl (R CollPathol). 1970; 4: 166–171.

11. What breaks in the brain during Non-blast TBI? Modeling based on human neuropathology

12. “All models are wrong.Some are useful” George Box, 1979

13. HYGE Pneumatic actuator

14. Inertial Brain Injury in the Pig Deceleration Pre-Acceleration Acceleration

16. DAI is the source of immediate loss of consciousness and coma Following non-blast brain trauma

17. 40- axial coronal 20- min LOC Mild TBI

18. Tensile elongation of axons

19. Culture Axonal Injury (CAI)

22. Glu Tyr

23. In vivo strain gauge after head Would this occur in blast TBI? 18 y/o F MVA 22h survival Adult Pig 3 h survival 18 y/o M Assault 10 h survival

24. MT twisting & breakage

25. Stretch injury triggers microtubule instability

26. APP 18 y/o M Assault 10 h survival Mechanical failure of axonal cytoskeleton may be unique to TBI

27. Undulations Varicosities Bulbs together in acute/ subacute human non-blast TBI

28. Pre-injury Post-injury 3% strain 5% strain 20% strain Strain-dependent threshold for calcium influx with TAI

29. NaChimmunoreactivity Pre-injury 1hr post-injury 24hr post-injury Posttraumatic increase in NaCh density = NaChO?

30. Human blast TBI pathology

32. Scientistswould rather share atoothbrushthan use each other’s paradigms Poor consensus for animal models of non-blast TBI. Blast TBI models – far less consensus

33. bTBI animal models: is there DAI as seen in non-blast TBI?

34. Shock Tube Testing(Penn & NMRC) WRAIR/ NMRC shocktube

35. Photonic Nanocrystals in Nature

36. Exploit Mechanical Failure of Photonic Crystals Crystal Failure Sonic Blast

37. Blast Injury Dosimeter ArraysTested at NMRC

38. Blast Injury Dosimeter pre-blast post-blast

39. Gross Pathology Shockwave peak overpressure 120 – 140 kPa

40. Neuronal Degeneration

41. Reactive Astrocytosis

42. Axonal Pathology Sham Blast (24hr) FPI APP NF 200

43. Silver Staining (Cortex, 120 kPa) 24hrs sham 48hrs 3hrs 4x 20x

44. Silver Staining (120 kPa) sham 24hrs 48hrs DG 10x CC 20x

45. Diffusion tensor imaging of mild to moderate blast-related traumatic brain injury and its sequelae. Levin HS, et al. J Neurotrauma. 2010 Apr;27(4):683-94 “Our data do not show WM injury in mild to moderate blast-related TBI in veterans despite their residual symptoms and difficulty in verbal memory”

46. Classic silver staining of axonal pathology Deep white matter Classic silver staining of axonal pathology Corpus callosum and internal capsule after Non-blast TBI Classic silver staining of non-blast DAI for comparison

48. Whole Body Lateral Exposure

49. No Gross Pathology

50. p-NFH changes last up to 7d

51. Axonal transport disruption?Post-BLAST (18Hr) Post-BLAST (18Hr) SÄLJÖ, A; BAO, F; HAGLID, KG; HANSSON, H-A. (2000). J Neurotrauma; Vol 17:18.719-728

52. Amyloid Precursor Protein 21d POST-BLAST (CTX - RAT) SÄLJÖ, A; BAO, F; SHI, J; HAMBERGER, A; HANSSON, H-A; HAGLID, KG. (2002)J Neurotrauma Vol 19, Issue 3, Pg 105-111

53. Silver Stain: Moderate Charge Exposed to Swine within a Building Baumen, RA et al. J Neurotrauma; 26:841–860 (June 2009)

54. Silver Stain: Moderate Charge Exposed to Swine within a Building Ipsilateral Frontal CTX Baumen, RA et al. J Neurotrauma; 26:841–860 (June 2009)

55. Blast Overpressure Generated using compression-driven shock tube Long, JB et al. J Neurotrauma; 26:827–840 (June 2009)

56. Long, JB et al. J Neurotrauma; 26:827–840 (June 2009)

57. Corpus Callosum (APP) CerebellarPeduncle:Gallyas Silver Stain Gallyas Silver Stain Koliatsos, VE et al. J Neuropathol Exp Neurol. 70;5;399-416, 2011

58. “Exposure in the blast tube did not induce DAI” Mechanisms of blast induced brain injuries, experimental studies in rats. Risling et al.Neuroimage. 2011:S89-97.

59. EFFECT OF BLAST EXPOSURE ON THE BRAIN STRUCTURE AND COGNITION IN THE MACACA FASCICULARIS JiaLU et al., J. Neurotrauma, in press No DAI reported, but apparent demyelination, disorganized myelin, vaculoes and loss of structure MBP EM

60. Microglial Activation and Astrocytosis Following Blast-Injury (Rat) Microglia (OX-42) in CA1 GFAP in CA1 SHAM SHAM 7d Post BLAST 21d Post BLAST SÄLJÖ, A; BAO, F; HAMBERGER, A; HAGLID, KG; HANSSON, H-A. (2001). Pathophysiology Vol 8, Issue 2, Pg 105-111

61. Microglial Activation Following exposure of Rats to Air-Driven Shock-Tube Readnower RD et al, J Neurosci Re; 88;3530-3539

62. Moderate Charge Exposed to Swine within a Building GFAP (superior corona radiata) Ipsilateral Contralateral Baumen, RA et al. J Neurotrauma; 26:841–860 (June 2009)

63. EFFECT OF BLAST EXPOSURE ON THE BRAIN STRUCTURE AND COGNITION IN THE MACACA FASCICULARIS JiaLU et al., J. Neurotrauma, in press S100ß

64. Hemorrhage? No hemorrhage Intraparenchymal bleeding Subarachnoid hemorrhage Subdural hemorrhage Cortical Contusion Microbleeds –Capillary leakage Chen, J et al Journal of the Neurological Sciences 294 (2010) 23–28 Kado et al. JNeurosurg 106:667–676, 2007 SÄLJÖ, A. J Neurotrauma; 25:1397–1406 (2008)

66. Ionic fluxes

67. Acute/ Chronic channelopathy

68. Transport interruption

69. Swellings (varicosities and bulbs)

70. Wallerian degenerationBlast axonal pathology: -limited axonal swellings -darker silver and IHC staining of brain regions -myelin changes? -as yet undetected type of subcellular damage?

71. Blast TBI Models: Hemorrhage – not found in clinical blast mTBI No strong evidence of extensive DAI/ TAI Modest neuronal degeneration Uniform inflammation across models Does not fit current hypotheses of mild bTBI in humans

72. Are swollen axons the predominant pathology of DAI?

74. Shu Yang, Ph.D., and YonganXu, Ph.D., Materials Science and Engineering, Univ. of Pennsylvania

75. James Geddes, Ph.D., Univ. of Kentucky

76. MikulasChavko, Ph.D., and Richard M. McCarron, Ph.D., Naval Medical Research Center

77. Funding: NIH (NS38104) and Nanotechnology Institute (NTI)