Role of leukocytes in cerebral autoregulation and hyperemia in bacterial meningitis in rabbits

Anthony J. Slater, Ivor David Berkowitz, David A. Wilson, Richard J. Traystman

Research output: Contribution to journalArticle

Abstract

The effect of leukocytes on regional cerebral blood now (rCBF) and cerebrovascular autoregulation in experimental meningitis was determined in rabbits. Four groups of animals were studied. Cerebrospinal fluid (CSF) leukocyte migration was prevented in two groups by pretreatment with 1. 5 mg/kg of IB4, a monoclonal antibody directed against CD11/18 leukocyte adhesion receptors. Intracisternal inoculation was performed with saline (control and control-IB4 groups) or Haemophilus influenzae type b (Hib and Hib-IB4 groups). Eighteen hours later, rCBF was determined with radiolabeled microspheres. Autoregulation was assessed by graded hemorrhagic hypotension. Compared with untreated meningitis (Hib group), IB4-pretreated meningitis (Hib-IB4 group) was associated with a reduced CSF leukocyte count (1, 980 ±880 vs. 200 ±110 cells/;/!; P <0. 05) and an elevated CSF colony count (2. 87 ±0. 08 vs. 5. 63 ±0. 72 logjocolony-forming units/ml; P <0. 05). Compared with control, baseline CBF was elevated in both untreated and IB4-pretreated meningitis (51 ±2, 54 ±2, 66 ±5, and 102 ± 17 ml-100 g-min-1 in control, control-IB4, Hib, and HibIB4 groups, respectively). The degree of hyperemia in meningitis was related to the CSF colony count, with a high CBF occurring in animals with high colony counts. During hypotension, CBF remained at or above baseline in the Hib group and both control groups, indicating preservation of cerebrovascular autoregulation in untreated Hib meningitis. In the HibIB4 group, the elevated baseline CBF was not maintained during hypotension, falling to 51% of baseline at a cerebral perfusion pressure of 30 mmHg and indicating impairment of cerebrovascular autoregulation. These results suggest that CSF leukocytes are not primarily responsible for the hyperemic response in Hib meningitis. Cerebral hyperemia may be induced either directly by bacterial components or indirectly by components of the inflammatory cascade that precede CSF leukocyte migration.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume42
Issue number1
StatePublished - 1997

Fingerprint

Haemophilus influenzae type b
Bacterial Meningitides
Hyperemia
Leukocytes
Homeostasis
Meningitis
Rabbits
Cerebrospinal Fluid
Hypotension
Leukocyte-Adhesion Receptors
Cerebrovascular Circulation
Control Groups
Microspheres
Leukocyte Count
Monoclonal Antibodies

Keywords

  • Cerebral blood flow
  • Haemophilus influenzae type b
  • Inflammation
  • Integrins

ASJC Scopus subject areas

  • Physiology

Cite this

Role of leukocytes in cerebral autoregulation and hyperemia in bacterial meningitis in rabbits. / Slater, Anthony J.; Berkowitz, Ivor David; Wilson, David A.; Traystman, Richard J.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 42, No. 1, 1997.

Research output: Contribution to journalArticle

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