epidermal-growth-factor and Shock--Septic

Surgical excision of submandibular salivary glands (sialoadenectomy) alters cell turnover in mice liver. Here we show that the liver of adult mice contained scattered leukocyte infiltration foci whose size was in the range of the diameter of hepatocytes. The number of infiltration foci in the liver increased soon after sialoadenectomy and remained high for several weeks. Neutrophils were recruited on dying hepatocytes soon after the initiation of the apoptotic process. Kupffer cells appeared later in the process. Just 2 days after sialoadenectomy, the number of type I infiltration foci (corresponding to the first stage) had increased 5-fold. Since these alterations in liver structure are coincident with a transient decrease in plasma EGF concentration, we studied whether inhibition of EGF receptor by means of genistein injection produced a similar effect. After three days of genistein administration, the number of type I infiltration foci increased 3.5-fold. Sialoadenectomized mice were more susceptible than controls to endotoxin shock. While 90% of sham-operated mice survived a burst of 100 microg lipopolysaccharide/Kg (combined with D-galactosamine 750 mg/Kg), only 50% of sialoadenectomized mice survived. The surviving sialoadenectomized mice recovered more slowly than the controls, as indicated by the high plasma alanine transaminase activity a week after the burst. We conclude that (i) neutrophils and macrophages participate in the process of apoptotic hepatocyte removal in a sequential manner; (ii) although the alteration of liver structure induced by sialoadenectomy is mild, it has delayed consequences on the ability of the liver to deal with aggressive insults.

Topics: Animals; Apoptosis; Disease Models, Animal; Epidermal Growth Factor; ErbB Receptors; Genistein; Hepatocytes; Kupffer Cells; Lipopolysaccharides; Liver; Macrophage Activation; Male; Mice; Neutrophil Infiltration; Neutrophils; Shock, Septic; Submandibular Gland; Time Factors

Acute and intense psychological stressors induce cell damage in several organs, including the heart and the liver. Much less is known about social stress. In male mice, aggressive behavior is the most common social stressor. It is remarkable that upon fighting, submandibular salivary glands release a number of peptides into the bloodstream including epidermal growth factor (EGF). We showed previously that released EGF protects the heart from cell damage in this particular stressful situation. Here, we studied the effect of an aggressive encounter on the liver and whether EGF has a similar effect on this organ. An aggressive encounter in male mice caused inflammatory response and a transient increase in plasma alanine and aspartate transaminase activities. At 3 h, focal infiltration of neutrophils was observed in liver parenchyma. These cells accumulate on eosinophilic hepatocytes, which may correspond to dying cells. A few hours later, evidence of necrotic lesion was observed. Surgical excision of submandibular glands, sialoadenectomy, did not prevent the rise in plasma EGF concentration and did not affect the increase in plasma transaminase activities. Neither did the administration of tyrphostin AG-1478 (inhibitor of EGF receptor kinase) alter the increase in plasma alanine transaminase activity. However, it did enhance the rise in both aspartate transaminase and creatine kinase activity, suggesting heart damage. We conclude that an aggressive encounter causes mild liver damage and that released EGF does not protect this organ, in contrast to its effect on the heart.

Topics: Aggression; Animals; Cell Death; Corticosterone; Epidermal Growth Factor; ErbB Receptors; Hepatocytes; Interleukin-6; Kupffer Cells; Liver; Liver Diseases; Liver Glycogen; Male; Mice; Neutrophils; Shock, Septic; Stress, Psychological; Tyrphostins

Local infection of the trachea in intubated neonates is one of the main risk factors for development of acquired subglottic stenosis, although its role in the pathogenesis is unclear. Methicillin resistant Staphylococcus aureus (MRSA) is often the cause of critical illness in neonatal patients. Two cases are reported of acquired subglottic stenosis following bacterial infection of the trachea, suggesting an association with the staphylococcal exotoxin, epidermal cell differentiation inhibitor (EDIN). EDIN-producing MRSA were isolated from purulent tracheal secretions from both infants. Acquired subglottic stenosis in both cases was probably caused by delayed wound healing as the result of EDIN inhibition of epithelial cell migration.

Topics: Epidermal Growth Factor; Female; Humans; Infant, Newborn; Intubation, Intratracheal; Laryngostenosis; Methicillin Resistance; Shock, Septic; Staphylococcal Infections; Staphylococcus aureus; Tracheotomy