Search

GI inflammation involves pathological processes affecting the gut epithelial barrier that are poorly reversible. A direct target of such processes is the enterocyte monolayer, which absorptive function is challenged by inflammation-induced cytoskeleton dynamics. Here, we evaluate the proinflammatory effects of PMA (phorbol-12-myristate-13-acetate) on Caco-2 intestinal cells at two different stages of spontaneous differentiation i.e. undifferentiated (7 dps, days post seeding) and differentiated enterocyte-like cells (>21 dps) in the presence/absence of the natural dipeptide carnosine (CAR) as potential anti-inflammatory molecule. By analysing actin cytoskeleton in 7 dps Caco-2 monolayers versus 21 dps monolayers, we revealed opposite effects of PMA which respectively induced disruption vs. intensification of actin rings and fibers; in both cases, simultaneous administration of PMA and CAR showed counteracting effects. Remarkably, the mRNA expression analysis of the ACTB (actin b) gene mirrored the morphological evidences and the counteraction of CAR. Moreover, the mRNA expression analysis of the AIF-1 gene (Allograft Inflammatory Factor 1) revealed opposite trends in 7 dps- versus 21 dps-grown Caco-2 with respect to PMA effects, and the same holds true for the SLC15A4/PHT1 gene involved both in intestinal peptide absorption and inflammatory responses; nevertheless, AIF-1 mRNA were not affected by CAR, whilst SLC15A4/PHT1 mRNA showed CAR-dependent up-regulation regardless of the differentiation stage. Overall, our results describe cytoskeletal and gene expression modulations which hint a model to distinguish physiological and inflammatory responses based on the differentiation stage of the Caco-2 monolayer and on the effects of CAR as differentially protective substrate.

SYNOPSIS Vasoactive substances have long been suspected to be of importance in the genesis of migraine. In vitro experiments carried out by us and partially published, resulted in significant data concerning the contracting activity of migraineiurs' sere on various isolated organs. In the present study, extracranial animal arteries were tested by means of blood samples taken under identical conditions. No contracting activity from sere taken both in the headache-free period and during the migraine crisis was observed in animal arteries. By contrast, each serum taken after the onset of the migraine crisis, showed a synergic effect on the action of histamine, serotonin and bradykinin. This synergic effect increases with the worsening of the attack, while it decreases as soon as the attack wears off.The experiments on human specimens provided data which cannot be evaluated yet. It seems likely that, on the occasion of the migraine attack, vasoactive substances which enable isolated organs to contract In vitro are released or activated. They synergistically increase the activity of serotonin and histamine.