Mucosal healing requires migration and proliferation. Most studies of focal adhesion kinase (FAK), a protein that regulates motility, proliferation, and apoptosis, have focused on rapid phosphorylation. We reported lower FAK protein levels in motile Caco-2 colon cancer cells and postulated that this reduction in FAK available for activation might impact cell migration and mucosal healing. Therefore, total and active FAK (FAK 397 ) immunoreactivity was assessed at the migrating fronts of human Caco-2 and rat IEC-6 intestinal epithelial cells. Caco-2 and IEC-6 motility, quantitated as migration into linear or circular wounds, was examined following FAK protein inhibition by small interfering RNA (siRNA). FAK protein stability and mRNA expression were ascertained by cycloheximide decay, RT-PCR, and in situ hybridization in static and migrating Caco-2 cells. Cells at the migrating front of Caco-2 and IEC-6 monolayers exhibited lower immunostaining for both total and activated FAK than cells immediately behind the front. Western blot analysis also demonstrated diminished FAK protein levels in motile cells by Ն30% in both the differential density seeding and multiple scrape models. siRNA FAK protein inhibition enhanced motility in both the linear scrape (20% in Caco-2) and circular wound (16% in Caco-2 and 19% in IEC-6 cells) models. FAK protein degradation did not differ in motile and static Caco-2 cells and was unaffected by FAK 397 phosphorylation, but FAK mRNA was lower in migrating Caco-2 cells. Thus FAK protein abundance appears regulated at the mRNA level during gut epithelial cell motility and may influence epithelial cell migration coordinately with signals that modify FAK phosphorylation.healing; migration; restitution; ulcer ALTHOUGH MOST PREVALENT in the stomach and duodenum, ulcers are found throughout the gastrointestinal tract. Regardless of site, mucosal ulcer healing is a complex process that involves restitution by migration of epithelial cells from the wound margins and eventual filling of the defect by proliferating epithelial and connective tissue cells (31, 43). Various factors have been shown to stimulate epithelial restitution and proliferation, but the intracellular signal proteins that control epithelial cellular migration are less well understood. Among these signals, activation of focal adhesion kinase (FAK) has been linked to gastric wound healing in vivo (41,44). FAK is a tyrosine kinase that associates with the cytoplasmic tail of clustered integrins in focal adhesion complexes. On activation, autophosphorylation of FAK on tyrosine 397 is followed by further phosphorylation of FAK itself and other proteins (36,56). Although FAK was originally described as being rapidly activated on integrin-mediated cell-matrix adhesion, this kinase has now been reported to be activated during epithelial cell motility and phosphorylated at both serine and tyrosine residues by many factors including occupancy of trans-activating G protein-coupled receptors (GPCRs) (10,23,35,51). Modulating FAK activity ...

Continuous intravenous infusion of prostacyclin is an effective treatment for primary pulmonary hypertension (PPH), and has recently been shown to be of benefit in PH associated with scleroderma (SSc). Pulmonary capillary hemangiomatosis (PCH) is a rare cause of PPH. Prostacyclin therapy has been complicated by pulmonary edema in cases of PCH. We describe a case of PH associated with limited SSc, where treatment with prostacyclin was complicated by pulmonary edema. Autopsy revealed PCH as the pathologic basis for the PH. There were no clinical features of PCH prior to initiation of vasodilator therapy, illustrating the potential difficulty in establishing the diagnosis. This is the first reported case of PCH in SSc.

Both models produce effective diastolic counterpulsation. Survival was decreased in this model using half ligation, and survival without complication was observed in 2 of 10 animals. Currently the overall results are better with the full aortic ligation model. However, design modifications will probably result in an effective model of diastolic counterpulsation without full aortic ligation.

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