Israel Medical Association Journal

The histopathology of severe persistent asthma and chronic obstructive pulmonary disease is predominantly characterized by neutrophilic inflammation. It is posited that chronic hypoxia from hypoventilation in combination with hypoperfusion and hypercapnia are associated with induction of pulmonary tissue acidosis in SPA[1] and COPD[2], which in turn provide ideal conditions to induce danger-associated molecular patterns, i.e., crystallized and calcium pyrophosphate. These stimuli in combination with other danger-related biochemical signals are capable of stimulating an innate immune receptor (cryopyrin inflammasome, NALP3) and cause interleukin-1β secretion with subsequent neutrophilic inflammation. There is evidence to suggest that the mechanisms and pathobiology associated with chronic hypoxia, reduced perfusion and reoxygenation in SPA/COPD may exhibit similarities to the biphasic pathobiology involved in ischemia-reperfusion injury. A rationale is suggested for trials of IL-1β[3] targeted therapies as an adjunct strategy to control neutrophilic inflammation in these conditions.

Background: The pathogenesis of neurological symptoms, the most common extraintestinal complication ofchildhood shigellosis, is unclear. To elucidate the mechanisms involved, we developed an animal model and demonstrated that TNF alpha and IL-1 beta play a role.

Objectives: To determine whether TNF alpha and IL-1 beta genes are expressed in the brain following peripheral administration of Shigella dysenteriae 60R.

Methods: Expression of mRNA for TNF alpha and IL-1 beta was examined in the brain structures (hypothalamus and hippocampus) and peripheral organs by reverse transcriptase polymerase chain reaction, at different time points after intraperitoneal injection of S. dysenteriae sonicate.

Results: In our animal model of Shigella related seizures, TNF alpha and IL-1 beta mRNA were induced in the brain, spleen and liver already 1 hour after injection of S. dysenteriae sonicate. The expression of TNF alpha and IL-1 beta mRNA in spleen, hippocampus and hypothalamus decreased after 6 h and increased again at 18 h post-injection.

Conclusions: Local production of TNF alpha and IL-1 beta in the brain may be involved in the enhanced seizure response of mice after administration of S. dysenteriae. It is possible that intracerebral production of TNF alpha and IL-1 beta plays a role in neurological disturbances of human shigellosis.