When the air hits your brain: decreased arterial pulsatility after craniectomy leading to impaired glymphatic flow

Restricted access

OBJECTIVE

Cranial neurosurgical procedures can cause changes in brain function. There are many potential explanations, but the effect of simply opening the skull has not been addressed, except for research into syndrome of the trephined. The glymphatic circulation, by which CSF and interstitial fluid circulate through periarterial spaces, brain parenchyma, and perivenous spaces, depends on arterial pulsations to provide the driving force for bulk flow; opening the cranial cavity could dampen this force. The authors hypothesized that a craniectomy, without any other pathological insult, is sufficient to alter brain function due to reduced arterial pulsatility and decreased glymphatic flow. Furthermore, they postulated that glymphatic impairment would produce activation of astrocytes and microglia; with the reestablishment of a closed cranial compartment, the glymphatic impairment, astrocytic/microglial activation, and neurobehavioral decline caused by opening the cranial compartment might be reversed.

METHODS

Using two-photon in vivo microscopy, the pulsatility index of cortical vessels was quantified through a thinned murine skull and then again after craniectomy. Glymphatic influx was determined with ex vivo fluorescence microscopy of mice 0, 14, 28, and 56 days following craniectomy or cranioplasty; brain sections were immunohistochemically labeled for GFAP and CD68. Motor and cognitive performance was quantified with rotarod and novel object recognition tests at baseline and 14, 21, and 28 days following craniectomy or cranioplasty.

RESULTS

Penetrating arterial pulsatility decreased significantly and bilaterally following unilateral craniectomy, producing immediate and chronic impairment of glymphatic CSF influx in the ipsilateral and contralateral brain parenchyma. Craniectomy-related glymphatic dysfunction was associated with an astrocytic and microglial inflammatory response, as well as with the development of motor and cognitive deficits. Recovery of glymphatic flow preceded reduced gliosis and return of normal neurological function, and cranioplasty accelerated this recovery.

CONCLUSIONS

Craniectomy causes glymphatic dysfunction, gliosis, and changes in neurological function in this murine model of syndrome of the trephined.

ABBREVIATIONS aCSF = artificial CSF; AP = anterior-posterior; AU = absolute unit; ICP = intracranial pressure; IgG = immunoglobulin G; ISF = interstitial fluid; ML = medial-lateral; NDS = normal donkey serum; OA-555 = Alexa Fluor 555–conjugated ovalbumin; PBS = phosphate-buffered saline; ROI = region of interest; TBI = traumatic brain injury; TCD = transcranial Doppler; TRITC = tetramethylrhodamine.

Article Information

Correspondence Maiken Nedergaard: Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY. maiken_nedergaard@urmc.rochester.edu.

INCLUDE WHEN CITING Published online May 17, 2019; DOI: 10.3171/2019.2.JNS182675.

Disclosures Dr. Iliff reports being a consultant for GlaxoSmithKline.

© AANS, except where prohibited by US copyright law.

Headings

Figures

  • View in gallery

    Surgical preparation of craniectomy and cranioplasty. Left: A 2-mm-diameter craniectomy window overlying the right temporoparietal cortex (−2.0 mm AP, 2.0 mm ML). Following drilling, the bone flap is carefully lifted from the skull and the underlying dura removed with fine forceps. In mice designated for cranioplasty, a small subcutaneous pocket is bluntly dissected between the scapulae for preservation of the bone flap until the time of cranioplasty. Sagittal suture (white dashed line); margin of craniectomy window (black dashed circle). Right: At 14 days, the bone flap (black arrow) is retrieved from between the scapulae and gently placed within the craniectomy window. A mixture of cyanoacrylate and dental cement is used to secure the bone flap to the surrounding skull (black arrowhead). Sagittal suture (white dashed line).

  • View in gallery

    Cerebral penetrating arterial pulsatility is reduced by craniectomy. A: Experimental timeline. B: The cerebrovascular column is visualized by introducing a large fluorescently labeled dextran (TRITC-dextran, 2000 kD) intravenously (center image: collapsed 100 μm XYZ stack, magnification ×20). Three-second XT line scans orthogonal to the vessel axis, capturing the dynamic change in vessel diameter across time, are acquired at the surface of the brain (orange line, left image) or at a depth of 100 μm below the brain’s surface (orange line, right image) to control for any changes in vascular pulsatility arising from variable cortical depth. C: Representative XT line scan, where the horizontal axis corresponds to the orange lines seen in the left and right images of B, and the vertical axis is the time vector. D: Summary data demonstrating a decreased pulsatility index in the hemisphere ipsilateral to craniectomy compared to the thin skull preparation, specifically within penetrating arteries, but not at any other level of the cerebrovascular tree. **p < 0.01, craniectomy versus thin skull; two-way repeated measures ANOVA with a Sidak correction for multiple comparisons; n = 4 mice, 12 vessels imaged in both conditions. E: Summary data demonstrating decreased penetrating arterial pulsatility in both the ipsilateral and contralateral hemispheres. **p < 0.01, craniectomy versus thin skull; paired two-tailed t-test; n = 4 mice, 12 vessels imaged for the ipsilateral craniectomy groups and n = 6 mice, 18 vessels imaged for the contralateral craniectomy groups. All data are presented as the mean ± SEM. Contra = contralateral; crani = craniectomy; ipsi = ipsilateral; 2P = two-photon.

  • View in gallery

    Decreased glymphatic influx immediately following craniectomy. A: Schematic diagram of injection of the fluorescent protein tracer, OA-555 (45 kD), to the cisterna magna for the assay of glymphatic influx. B: Experimental timeline. C: Five ROIs (left) drawn both ipsilateral and contralateral to the position of the craniectomy: hemisphere (HS), cortex (Ctx), white matter (WM; encompassing the corpus callosum and external capsule), hippocampus (HC), and subcortex (SCtx). This is a representative image of control glymphatic CSF tracer influx (green), and the same image thresholded (white; right) to only capture pixels above a predetermined intensity level. D: Representative images of glymphatic tracer influx in craniectomy-treated mice (green, left) and the same image after an intensity threshold has been applied (white, right). E: Glymphatic CSF influx is measured by quantifying the percentage of area occupied by OA-555 above the applied intensity threshold in each of the ROIs identified above. Summary data reveal that craniectomy results in significantly reduced glymphatic flow, both ipsilateral and contralateral to the craniectomy, at the level of the hemisphere, white matter, and subcortex. All data are normalized to control levels within each ROI and are presented as the mean ± SEM. *p < 0.05 and **p < 0.01 versus control; one-way ANOVA with a Tukey’s multiple comparisons test within each ROI; n = 6 mice/group. All scale bars = 1 mm.

  • View in gallery

    Prolonged impairment of glymphatic influx due to chronic craniectomy. A: Schematic of cisterna magna injection of the fluorescent protein tracer, OA-555 (45 kD), to assay glymphatic influx. B: Experimental timeline. C: For image quantification, five ROIs (upper) ipsilateral and contralateral to the site of the craniectomy or cranioplasty are drawn: hemisphere (HS), cortex (Ctx), white matter (WM; including corpus callosum and external capsule), hippocampus (HC), and subcortex (SCtx). C–F: Representative images of glymphatic CSF tracer influx in control (C); 14-day craniectomy (D, upper image); 28-day craniectomy (E, upper image) and cranioplasty (E, lower image); and 56-day craniectomy (F, upper image) and cranioplasty (F, lower image). C and D: Representative images (lower images) demonstrating the application of a threshold to only include pixels above a predetermined intensity from the above (green) images. G–I: Glymphatic CSF tracer influx is measured by quantifying the thresholded percentage of area occupied by OA-555 in each of the ROIs defined above. Summary data demonstrate persistent impairment of glymphatic flow, within both ipsilateral and contralateral structures, out to at least 14 days after craniectomy. By day 28, however, glymphatic CSF influx is found to spontaneously recover, independently of the presence of cranioplasty (CP). All data are normalized to control levels within each ROI and are presented as the mean ± SEM. *p < 0.05 and **p < 0.01 versus control; one-way ANOVA with a Tukey’s multiple comparisons test within each ROI; n = 4–6 mice/group. All scale bars = 1 mm.

  • View in gallery

    Chronic craniectomy and glymphatic impairment drive reactive astrogliosis. A: Experimental timeline. B–G: Representative images of glial GFAP immunofluorescence (green), and the same images with a threshold applied to capture pixels above a predetermined intensity level (white), for controls (B); 14-day craniectomy (C); 28-day craniectomy (D) and cranioplasty (E); and 56-day craniectomy (F) and cranioplasty (G). All images are collapsed 40-μm XYZ stacks with a 5-μm step size. H: Astrogliosis is measured by quantifying the percentage of area above the defined intensity threshold occupied by GFAP within each high-powered field. Summary data demonstrate that there is persistent astrogliosis in the cortex ipsilateral to the craniectomy out to at least 28 days. Cranioplasty, however, accelerated recovery of the noninflamed phenotype by day 28. All data are normalized to control levels within each ROI and are presented as the mean ± SEM. *p < 0.05 and **p < 0.01 versus control or between designated groups; one-way ANOVA with a Tukey’s multiple comparisons test at each time point; n = 4–6 mice/group. All scale bars = 100 μm. IHC = immunohistochemistry.

  • View in gallery

    Chronic craniectomy and glymphatic stagnation leads to reactive microgliosis. A: Experimental timeline. B–G: Representative images of CD68 immunofluorescence (magenta) and the same images with a threshold applied to only capture pixels above a predetermined intensity level (white), for controls (B); 14-day craniectomy (C); 28-day craniectomy (D) and cranioplasty (E); and 56-day craniectomy (F) and cranioplasty (G). All images depicted are collapsed 40-μm XYZ stacks with a 5-μm step size. H: Microglial reactivity is measured by quantifying the percentage of area above the defined intensity threshold occupied by CD68 within each high-powered field. Summary data show that there is increased microglial activation ipsilateral and contralateral to the craniectomy at day 14. Furthermore, this microgliosis persists out to at least 28 days in the cortex ipsilateral to the craniectomy; however, cranioplasty appears to normalize microglial CD68 expression by this same time point. All data are normalized to control levels within each ROI and are presented as the mean ± SEM. *p < 0.05 and ****p < 0.0001 versus control or between designated groups; one-way ANOVA with a Tukey’s multiple comparisons test at each time point; n = 4–6 mice/group. All scale bars = 100 μm.

  • View in gallery

    Motor and cognitive deficits emerge following chronic craniectomy and prolonged glymphatic dysfunction. A: Experimental timeline: mice within the craniectomy, cranioplasty, and control cohorts undergo neurobehavioral assessment for locomotor function, coordinated motor function, and object working memory with the open-field, rotarod, and novel object recognition tests, respectively, at baseline and on days 14, 21, and 28. B and C: Summary data finding no differences in the open-field locomotor measures of mean speed (meters/second) (B) and distance traveled (meters) (C). D: Summary data of coordinated motor performance on the rotarod demonstrating significantly shorter latencies to fall for the craniectomy cohort compared to the control cohort at 21 and 28 days. Cranioplasty-treated mice do not demonstrate significantly different fall latencies at any time points relative to control mice. E: Summary data of object working memory performance within the novel object recognition test finding significantly impaired novel object identification for both the craniectomy and cranioplasty cohorts at 21 days relative to controls. By 28 days, mice in the cranioplasty group do not have any apparent deficits in identifying the novel object; however, there is a trend toward impaired novel object discernment for the craniectomy-treated mice compared to the cranioplasty-treated mice. All data are presented as the mean ± SEM. *p < 0.05 and ***p < 0.001; magenta symbol indicates craniectomy versus control and blue symbol indicates cranioplasty versus control; repeated measures two-way ANOVA with a Tukey’s multiple comparisons test at all time points; n = 9–20 mice/group.

  • View in gallery

    Summary of impact of craniectomy on glymphatic flow, neuroinflammation, and neurobehavioral function. A–D: There is impaired glymphatic CSF influx immediately following decompressive craniectomy and lasting out to a point between 14 and 28 days following decompression, regardless of whether cranioplasty is performed. In association with this glymphatic stagnation, there is increased astrocytic and microglial reactivity at 14 and 28 days following craniectomy; however, if cranioplasty is performed, there is a reduction in both GFAP and CD68 expression to control levels at 28 days. Finally, by 21 days following craniectomy, there is impaired cognitive and motor performance on the novel object and rotarod assessments, respectively, and motor deficits persist out to 28 days. If cranioplasty is performed, there is a trend toward impaired cognitive and motor function at 14 days, and there is significantly impaired cognition at 21 days, but all neurological deficits are reversed by 28 days. A: Increasing light green on y-axis represents increasing OA-555 percent area. B and C: Increasing dark green or purple on y-axis represents increasing GFAP or CD68 percent area, respectively. D: The y-axis represents latency to fall for the rotarod assessment and percentage of time spent with the novel object for the novel object recognition test. Solid lines indicate craniectomy; dotted lines denote cranioplasty.

References

  • 1

    Abbott NJ: Evidence for bulk flow of brain interstitial fluid: significance for physiology and pathology. Neurochem Int 45:5455522004

  • 2

    Balestreri MCzosnyka MHutchinson PSteiner LAHiler MSmielewski P: Impact of intracranial pressure and cerebral perfusion pressure on severe disability and mortality after head injury. Neurocrit Care 4:8132006

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Bevins RABesheer J: Object recognition in rats and mice: a one-trial non-matching-to-sample learning task to study ‘recognition memory’. Nat Protoc 1:130613112006

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Bor-Seng-Shu EHirsch RTeixeira MJDe Andrade AFMarino R Jr: Cerebral hemodynamic changes gauged by transcranial Doppler ultrasonography in patients with posttraumatic brain swelling treated by surgical decompression. J Neurosurg 104:931002006

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Cai RPan CGhasemigharagoz ATodorov MIFörstera BZhao S: Panoptic imaging of transparent mice reveals whole-body neuronal projections and skull-meninges connections. Nat Neurosci 22:3173272019

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Cooper DJRosenfeld JVMurray LArabi YMDavies ARD’Urso P: Decompressive craniectomy in diffuse traumatic brain injury. N Engl J Med 364:149315022011

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Cserr HF: Physiology of the choroid plexus. Physiol Rev 51:2733111971

  • 8

    Cserr HFCooper DNSuri PKPatlak CS: Efflux of radiolabeled polyethylene glycols and albumin from rat brain. Am J Physiol 240:F319F3281981

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9

    Daboussi AMinville VLeclerc-Foucras SGeeraerts TEsquerré JPPayoux P: Cerebral hemodynamic changes in severe head injury patients undergoing decompressive craniectomy. J Neurosurg Anesthesiol 21:3393452009

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Damkier HHBrown PDPraetorius J: Cerebrospinal fluid secretion by the choroid plexus. Physiol Rev 93:184718922013

  • 11

    De Bonis PSturiale CLAnile CGaudino SMangiola AMartucci M: Decompressive craniectomy, interhemispheric hygroma and hydrocephalus: a timeline of events? Clin Neurol Neurosurg 115:130813122013

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 12

    Dujovny MFernandez PAlperin NBetz WMisra MMafee M: Post-cranioplasty cerebrospinal fluid hydrodynamic changes: magnetic resonance imaging quantitative analysis. Neurol Res 19:3113161997

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Eide PKRingstad G: MRI with intrathecal MRI gadolinium contrast medium administration: a possible method to assess glymphatic function in human brain. Acta Radiol Open 4:20584601156096352015

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Fodstad HLove JAEkstedt JFridén HLiliequist B: Effect of cranioplasty on cerebrospinal fluid hydrodynamics in patients with the syndrome of the trephined. Acta Neurochir (Wien) 70:21301984

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Herisson FFrodermann VCourties GRohde DSun YVandoorne K: Direct vascular channels connect skull bone marrow and the brain surface enabling myeloid cell migration. Nat Neurosci 21:120912172018

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Holness CLSimmons DL: Molecular cloning of CD68, a human macrophage marker related to lysosomal glycoproteins. Blood 81:160716131993

  • 17

    Honeybul SHo KM: Incidence and risk factors for post-traumatic hydrocephalus following decompressive craniectomy for intractable intracranial hypertension and evacuation of mass lesions. J Neurotrauma 29:187218782012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Honeybul SHo KM: Long-term complications of decompressive craniectomy for head injury. J Neurotrauma 28:9299352011

  • 19

    Hong JYSuh SWPark SYModi HNRhyu IJKwon S: Analysis of dural sac thickness in human spine-cadaver study with confocal infrared laser microscope. Spine J 11:112111272011

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Hutchinson PJKolias AGTimofeev ISCorteen EACzosnyka MTimothy J: Trial of decompressive craniectomy for traumatic intracranial hypertension. N Engl J Med 375:111911302016

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Iliff JJChen MJPlog BAZeppenfeld DMSoltero MYang L: Impairment of glymphatic pathway function promotes tau pathology after traumatic brain injury. J Neurosci 34:16180161932014

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Iliff JJLee HYu MFeng TLogan JNedergaard M: Brain-wide pathway for waste clearance captured by contrast-enhanced MRI. J Clin Invest 123:129913092013

  • 23

    Iliff JJWang MLiao YPlogg BAPeng WGundersen GA: A paravascular pathway facilitates CSF flow through the brain parenchyma and the clearance of interstitial solutes, including amyloid β. Sci Transl Med 4:147ra1112012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Iliff JJWang MZeppenfeld DMVenkataraman APlog BALiao Y: Cerebral arterial pulsation drives paravascular CSF-interstitial fluid exchange in the murine brain. J Neurosci 33:18190181992013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    Joseph VReilly P: Syndrome of the trephined. J Neurosurg 111:6506522009

  • 26

    Kolias AGKirkpatrick PJHutchinson PJ: Decompressive craniectomy: past, present and future. Nat Rev Neurol 9:4054152013

  • 27

    Kress BTIliff JJXia MWang MWei HSZeppenfeld D: Impairment of paravascular clearance pathways in the aging brain. Ann Neurol 76:8458612014

  • 28

    Kurland DBKhaladj-Ghom AStokum JACarusillo BKarimy JKGerzanich V: Complications associated with decompressive craniectomy: a systematic review. Neurocrit Care 23:2923042015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 29

    Lazaridis CDeSantis SMVandergrift AWKrishna V: Cerebral blood flow velocity changes and the value of the pulsatility index post decompressive craniectomy. J Clin Neurosci 19:105210542012

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30

    Lee HXie LYu MKang HFeng TDeane R: The effect of body posture on brain glymphatic transport. J Neurosci 35:11034110442015

  • 31

    Liang WXiaofeng YWeiguo LGang SXuesheng ZFei C: Cranioplasty of large cranial defect at an early stage after decompressive craniectomy performed for severe head trauma. J Craniofac Surg 18:5265322007

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32

    Louveau APlog BAAntila SAlitalo KNedergaard MKipnis J: Understanding the functions and relationships of the glymphatic system and meningeal lymphatics. J Clin Invest 127:321032192017

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 33

    Lundgaard ILu MLYang EPeng WMestre HHitomi E: Glymphatic clearance controls state-dependent changes in brain lactate concentration. J Cereb Blood Flow Metab 37:211221242017

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 34

    Peng WAchariyar TMLi BLiao YMestre HHitomi E: Suppression of glymphatic fluid transport in a mouse model of Alzheimer’s disease. Neurobiol Dis 93:2152252016

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 35

    Plog BADashnaw MLHitomi EPeng WLiao YLou N: Biomarkers of traumatic injury are transported from brain to blood via the glymphatic system. J Neurosci 35:5185262015

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 36

    Plog BANedergaard M: The glymphatic system in central nervous system health and disease: past, present, and future. Annu Rev Pathol 13:3793942018

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 37

    Rangroo Thrane VThrane ASPlog BAThiyagarajan MIliff JJDeane R: Paravascular microcirculation facilitates rapid lipid transport and astrocyte signaling in the brain. Sci Rep 3:25822013

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 38

    Ratner VZhu LKolesov INedergaard MBenveniste HTannenbaum A: Optimal-mass-transfer-based estimation of glymphatic transport in living brain. Proc SPIE Int Soc Opt Eng 9413:94131J2015

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 39

    Ren ZIliff JJYang LYang JChen XChen MJ: ‘Hit & Run’ model of closed-skull traumatic brain injury (TBI) reveals complex patterns of post-traumatic AQP4 dysregulation. J Cereb Blood Flow Metab 33:8348452013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 40

    Shih AYMateo CDrew PJTsai PSKleinfeld D: A polished and reinforced thinned-skull window for long-term imaging of the mouse brain. J Vis Exp 61:162012

    • Search Google Scholar
    • Export Citation
  • 41

    Soustiel JFSviri GEMahamid EShik VAbeshaus SZaaroor M: Cerebral blood flow and metabolism following decompressive craniectomy for control of increased intracranial pressure. Neurosurgery 67:65722010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 42

    Stiver SI: Complications of decompressive craniectomy for traumatic brain injury. Neurosurg Focus 26(6):E72009

  • 43

    Szentistványi IPatlak CSEllis RACserr HF: Drainage of interstitial fluid from different regions of rat brain. Am J Physiol 246:F835F8441984

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 44

    Timofeev IHutchinson PJ: Outcome after surgical decompression of severe traumatic brain injury. Injury 37:112511322006

  • 45

    Vertosick FT: When the Air Hits Your Brain: Tales From Neurosurgery. New York: WW Norton & Company1996

  • 46

    Wang MIliff JJLiao YChen MJShinseki MSVenkataraman A: Cognitive deficits and delayed neuronal loss in a mouse model of multiple microinfarcts. J Neurosci 32:17948179602012

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 47

    Yang XFWen LShen FLi GLou RLiu WG: Surgical complications secondary to decompressive craniectomy in patients with a head injury: a series of 108 consecutive cases. Acta Neurochir (Wien) 150:124112482008

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation

TrendMD

Metrics

Metrics

All Time Past Year Past 30 Days
Abstract Views 902 902 490
Full Text Views 182 182 145
PDF Downloads 143 143 112
EPUB Downloads 0 0 0

PubMed

Google Scholar