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Proc Natl Acad Sci U S A. 2011 Mar 1;108(9):3731-6. doi: 10.1073/pnas.1011774108. Epub 2011 Jan 18.

Blockade of TNF-α rapidly inhibits pain responses in the central nervous system.

Author information

1
Institute of Experimental and Clinical Pharmacology and Toxicology, Department of Internal Medicine 3, and Division of Neuroradiology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany.

Abstract

There has been a consistent gap in understanding how TNF-α neutralization affects the disease state of arthritis patients so rapidly, considering that joint inflammation in rheumatoid arthritis is a chronic condition with structural changes. We thus hypothesized that neutralization of TNF-α acts through the CNS before directly affecting joint inflammation. Through use of functional MRI (fMRI), we demonstrate that within 24 h after neutralization of TNF-α, nociceptive CNS activity in the thalamus and somatosensoric cortex, but also the activation of the limbic system, is blocked. Brain areas showing blood-oxygen level-dependent signals, a validated method to assess neuronal activity elicited by pain, were significantly reduced as early as 24 h after an infusion of a monoclonal antibody to TNF-α. In contrast, clinical and laboratory markers of inflammation, such as joint swelling and acute phase reactants, were not affected by anti-TNF-α at these early time points. Moreover, arthritic mice overexpressing human TNF-α showed an altered pain behavior and a more intensive, widespread, and prolonged brain activity upon nociceptive stimuli compared with wild-type mice. Similar to humans, these changes, as well as the rewiring of CNS activity resulting in tight clustering in the thalamus, were rapidly reversed after neutralization of TNF-α. These results suggest that neutralization of TNF-α affects nociceptive brain activity in the context of arthritis, long before it achieves anti-inflammatory effects in the joints.

PMID:
21245297
PMCID:
PMC3048151
DOI:
10.1073/pnas.1011774108
[Indexed for MEDLINE]
Free PMC Article

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