Elsevier

Resuscitation

Volume 85, Issue 5, May 2014, Pages 694-701
Resuscitation

Experimental paper
Regional TNFα mapping in the brain reveals the striatum as a neuroinflammatory target after ventricular fibrillation cardiac arrest in rats

https://doi.org/10.1016/j.resuscitation.2014.01.033Get rights and content

Abstract

Cardiac arrest (CA) triggers neuroinflammation that could play a role in a delayed neuronal death. In our previously established rat model of ventricular fibrillation (VF) CA characterized by extensive neuronal death, we tested the hypothesis that individual brain regions have specific neuroinflammatory responses, as reflected by regional brain tissue levels of tumor necrosis factor (TNF)α and other cytokines. In a prospective study, rats were randomized to 6 min (CA6), 8 min (CA8) or 10 min (CA10) of VF CA, or sham group. Cortex, striatum, hippocampus and cerebellum were evaluated for TNFα and interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12 and interferon gamma at 3 h, 6 h or 14 d after CA by ELISA and Luminex. Immunohistochemistry was used to determine the cell source of TNFα. CA resulted in a selective TNFα response with significant regional and temporal differences. At 3 h after CA, TNFα-levels increased in all regions depending on the duration of the insult. The most pronounced increase was observed in striatum that showed 20-fold increase in CA10 vs. sham, and 3-fold increase vs. CA6 or CA8 group, respectively (p < 0.01). TNFα levels in striatum decreased between 3 h and 6 h, but increased in other regions between 3 h and 14 d. TNFα levels remained twofold higher in CA6 vs. shams across brain regions at 14 d (p < 0.01). In contrast to pronounced TNFα response, other cytokines showed only a minimal increase in CA6 and CA8 groups vs. sham in all brain regions with the exception that IL-1β increased twofold in cerebellum and striatum (p < 0.01). TNFα colocalized with neurons. In conclusion, CA produced a duration-dependent acute TNFα response, with dramatic increase in the striatum where TNFα colocalized with neurons. Increased TNFα levels persist for at least two weeks. This TNFα surge contrasts the lack of an acute increase in other cytokines in brain after CA. Given that striatum is a selectively vulnerable brain region, our data suggest possible role of neuronal TNFα in striatum after CA and identify therapeutic targets for future experiments.

This study was approved by the University of Pittsburgh IACUC 1002340A-3.

Introduction

Overall mortality after cardiac arrest (CA) remains high, despite improvements in resuscitation and critical care.1 Neurocognitive disabilities are frequently observed in survivors from CA. Histological damage including neuronal cell loss was characterized in multiple experimental global ischemia–reperfusion insults. Several selectively vulnerable regions have been identified, namely hippocampus, cerebellar Purkinje neurons, lamina IV cortical layer and striatum.2, 3 Both the systemic inflammatory response to CA and the local central nervous system (CNS) specific response may contribute to the ultimate histological damage.

CA and resuscitation result in a systemic inflammatory response that has been compared to sepsis.4 Cytokines produced by multiple cells including resident CNS cells are considered a hallmark of inflammatory reaction to an insult. Systemic and CNS levels of various cytokines including tumor necrosis factor (TNF)α, interleukin (IL)-1, IL-6, IL-8, IL-10, and others are increased after CA.4, 5, 6, 7

We have recently established a rat model of ventricular fibrillation (VF) CA and characterized extensive neuronal death with characteristic regional pattern.8 We hypothesized that neuroinflammation after CA might also show a regional pattern and be related to the duration of the insult. Thus, we used ELISA and Luminex methods to explore regional brain tissue levels of multiple cytokines after 6, 8 and 10 min of VF CA in cortex, hippocampus, striatum and cerebellum at 3 and 6 h after restoration of spontaneous circulation (ROSC) to study the early inflammatory response to ischemia and reperfusion. We furthermore assessed TNFα levels in rats that survived for 2 weeks. We have used immunocytochemistry to identify the cell sources of TNFα.

Section snippets

Methods

The study protocol was approved by the Institutional Animal Care and Use Committee of the University of Pittsburgh. A total of 45 adult male Sprague–Dawley rats (350–400 g; Hilltop Lab Animals, Scottdale, PA) were used as described in detail previously. In brief, isoflurane-anesthetized rats were intubated and mechanically ventilated, while maintaining normothermia. After cannulations, rats were subjected to 6 min (CA6), 8 min (CA8) or 10 min (CA10) of untreated VF CA or sham, and 3 or 6 h of

Results

There were no significant group differences at baseline. As expected, CA resulted in significant duration-dependent derangements in multiple biochemical parameters (Table 1 – Supplemental File).

Rats in the CA10 group could not be weaned from the ventilator. Therefore, the cytokine profiles could only be studied at 3 h timepoint.

Cytokine levels after 3 h and 6 h of observation time are presented in Fig. 1, Fig. 2, Fig. 3. Significant differences between groups were detected for TNFα and IL-1β and

Discussion

This study was designed to explore the regional pattern of brain tissue cytokines early after VF CA to identify possible therapeutic targets. We used our established VF CA model characterized by neurologic impairment and extensive histological damage in multiple brain regions, including hippocampus and striatum.8

We found that brain tissue levels of TNFα are increased as early as 3 h after CA, being the most prominent in the striatum. This early TNFα response in the striatum was more pronounced

Conclusions

To our knowledge, this is a first exploratory study evaluating early regional cytokine profile in a clinically relevant VF CA model. CA induced cerebral cytokine production with a distinct spatial and temporal pattern and suggested neurons as an important early source of TNFα. Early after CA, the striatum showed marked increase in TNFα levels with highest levels after prolonged CA. 14 d after CA, brain tissue levels of TNFα remained increased over shams, but without regional differences. Our

Conflict of interest statement

All other authors report no conflict of interest.

Acknowledgements

Dr. Janata was supported by a Peter Safar Research Fellowship and Grant-in-Aid from the Laerdal Foundation for Acute Medicine, and by the Erwin Schroedinger Stipend. Dr. Uray was supported by the Max Kade Fellowship. Dr. Kochanek was supported by NS30318. Dr. Drabek was supported by the AHA #09BGIA2310196, the Laerdal Foundation and Anesthesia Seed Grant.

References (37)

  • J.T. Niemann et al.

    TNF-alpha blockade improves early post-resuscitation survival and hemodynamics in a swine model of ischemic ventricular fibrillation

    Resuscitation

    (2013)
  • M. Fries et al.

    Influence of mild therapeutic hypothermia on the inflammatory response after successful resuscitation from cardiac arrest

    J Crit Care

    (2009)
  • G. van der Wal et al.

    Influence of mild therapeutic hypothermia after cardiac arrest on hospital mortality

    Crit Care Med

    (2011)
  • K. Kawai et al.

    Global cerebral ischemia associated with cardiac arrest in the rat: I. Dynamics of early neuronal changes

    J Cereb Blood Flow Metab

    (1992)
  • C. Adrie et al.

    Successful cardiopulmonary resuscitation after cardiac arrest as a “sepsis-like” syndrome

    Circulation

    (2002)
  • T. Mussack et al.

    Serum S-100B and interleukin-8 as predictive markers for comparative neurologic outcome analysis of patients after cardiac arrest and severe traumatic brain injury

    Crit Care Med

    (2002)
  • J.T. Niemann et al.

    Cardiac function and the proinflammatory cytokine response after recovery from cardiac arrest in swine

    J Interferon Cytokine Res

    (2009)
  • A. Janata et al.

    Extracorporeal versus conventional cardiopulmonary resuscitation after ventricular fibrillation cardiac arrest in rats: a feasibility trial

    Crit Care Med

    (2013)
  • Cited by (22)

    • The immunology of the post-cardiac arrest syndrome

      2022, Resuscitation
      Citation Excerpt :

      Recent data has shown that the immune systems play an important role in post-cardiac arrest brain injury. In a rat model of cardiac arrest, parenchymal cells of the brain, particularly the striatum, produce the pro-inflammatory cytokines TNF-α and IL-1β as early as 3 hours after arrest.30 TNF-α staining was co-localized with glial fibrillary acidic protein positive cells in the striatum implicating TNF-α released from injured neurons as initiators of the local inflammatory cascade.

    • Chronic high-fat diet-induced obesity in gerbils increases pro-inflammatory cytokines and mTOR activation, and elicits neuronal death in the striatum following brief transient ischemia

      2018, Neurochemistry International
      Citation Excerpt :

      For instance, neuronal death in the hippocampal CA1 area occurs at 4 days after 5 min of transient ischemia in gerbils (Lee et al., 2016), whereas neuronal death in the striatum is shown at 4 days following 20 min transient ischemia, but not after 5 min of transient ischemia (Ohk et al., 2012). Many studies have suggested diverse factors that contribute to selective neuronal vulnerability following transient ischemia, such as neurotransmitter imbalance, oxidative stress and neuroinflammatory responses (Candelario-Jalil et al., 2001; Janata et al., 2014; Tang et al., 2000). However, underlying mechanisms of the vulnerability have not yet been fully understood.

    • Single administration of soluble epoxide hydrolase inhibitor suppresses neuroinflammation and improves neuronal damage after cardiac arrest in mice

      2016, Neuroscience Research
      Citation Excerpt :

      Wang et al. reported that the sEH inhibitor did not reduce the hippocampal mRNA expression of interleukin (IL)-1β, inducible nitric oxide synthase, or TNF-α 1 day after CA/CPR (Wang et al., 2013). The hippocampal TNF-α gradually increased after CA and the increased amount was significant but smaller than other regions, such as the striatum (Janata et al., 2014). Wang's measurement may be too early to examine the minute changes of TNF-α in the hippocampus.

    • Induction of TNF-α signaling cascade in neonatal rat brain during propofol anesthesia

      2015, International Journal of Developmental Neuroscience
      Citation Excerpt :

      Since propofol acts as a GABA agonist, the different outcomes in PND7 and PND14 could be due to the fact that GABA is excitatory in PND7 and inhibitory in PND14 (Ben-Ari and Spitzer, 2010). Moreover, conditions that determine whether TNF-α is protective or detrimental depend on multiple factors including concentration and timing of TNF-α production as well as crosstalk with other cellular signals (Barnum and Tansey, 2011; Zelova and Hosek, 2013; Janata et al., 2014). TNF-α upregulation and its contribution to neuronal cell death has been reported in different models, including ischemia and traumatic brain injury, but in these studies changes in TNF-α expression lasted for a days after the insult (Goodman et al., 1990; Liu et al., 1994; Loncarevic-Vasiljkovic et al., 2012; Yasuda et al., 2011).

    View all citing articles on Scopus

    A Spanish translated version of the abstract of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2014.01.033.

    View full text