Tissue response and wound healing after placement of two types of bioengineered grafts containing vital cells in submucosal maxillary pouches: an experimental pilot study in rabbits

PURPOSE: This pilot study evaluated the wound healing and tissue response after placement of two different skin substitutes in subgingival mucosal pouches in rabbits. MATERIALS AND METHODS: Four rabbits were selected to receive a commercially available skin substitute consisting of a collagen matrix with fibroblasts and an epithelial layer (test membrane 1) and a prototype device consisting of a collagen matrix with fibroblasts only (test membrane 2). In each rabbit, two horizontal incisions were made in the buccal alveolar mucosa of the maxilla bilaterally to create submucosal pouches. Three pouches in each animal were filled with either the test 1 or test 2 membranes, and one pouch was left without a membrane (sham-operated control). All rabbits were sacrificed after a healing period of 4 weeks, and histologic samples were prepared and examined. RESULTS: After a healing period of 1 month, both tested membranes were still visible in the sections. Test membrane 1 was still bilayered, contained inflammatory cells in its center, and was encapsulated by a thick fibrous tissue. Numerous ectopic calcifications were evident in the collagenous part of the membrane and in association with some basal epithelial cells. Test membrane 2 was also encapsulated in fibrous tissue, with inflammatory cells present only between the fibrous encapsulation and the remnants of the membrane. For test membrane 2, no calcifications were visible. CONCLUSIONS: Test membrane 1 seemed to be more resistant to degradation, but there was also a more pronounced inflammatory reaction in comparison to test membrane 2, especially in the vicinity of the keratinocytes. The significance of the ectopic calcifications, along with that of the resorption or degradation processes of both tested membranes, must be evaluated in future experimental studies, with different time points after implantation examine

Diffuse swelling of the buccal mucosa and palate as first and only manifestation of an extranodal non-Hodgkin 'double-hit' lymphoma: report of a case

Most of the lymphomas arising in the oral cavity are of B-cell origin. Among these, diffuse large B-cell lymphomas are the most common. Diffuse large B-cell lymphomas may exhibit more than one chromosomal rearrangement and are then referred to as 'double-hit' or 'triple-hit' lymphomas.

Alveolar inflammation in cystic fibrosis

In infected lungs of the cystic fibrosis (CF) patients, opportunistic pathogens and mutated cystic fibrosis transmembrane conductance regulator protein (CFTR) contribute to chronic airway inflammation that is characterized by neutrophil/macrophage infiltration, cytokine release and ceramide accumulation. We sought to investigate CF lung inflammation in the alveoli.

An in vitro triple cell co-culture model with primary cells mimicking the human alveolar epithelial barrier

A triple cell co-culture model was recently established by the authors, consisting of either A549 or 16HBE14o- epithelial cells, human blood monocyte-derived macrophages and dendritic cells, which offers the possibility to study the interaction of xenobiotics with those cells. The 16HBE14o- containing co-culture model mimics the airway epithelial barrier, whereas the A549 co-cultures mimic the alveolar type II-like epithelial barrier. The goal of the present work was to establish a new triple cell co-culture model composed of primary alveolar type I-like cells isolated from human lung biopsies (hAEpC) representing a more realistic alveolar epithelial barrier wall, since type I epithelial cells cover >93% of the alveolar surface. Monocultures of A549 and 16HBE14o- were morphologically and functionally compared with the hAEpC using laser scanning microscopy, as well as transmission electron microscopy, and by determining the epithelial integrity. The triple cell co-cultures were characterized using the same methods. It could be shown that the epithelial integrity of hAEpC (mean ± SD, 1180 ± 188 Ω cm(2)) was higher than in A549 (172 ± 59 Ω cm(2)) but similar to 16HBE14o- cells (1469 ± 156 Ω cm(2)). The triple cell co-culture model with hAEpC (1113 ± 30 Ω cm(2)) showed the highest integrity compared to the ones with A549 (93 ± 14 Ω cm(2)) and 16HBE14o- (558 ± 267 Ω cm(2)). The tight junction protein zonula occludens-1 in hAEpC and 16HBE14o- were more regularly expressed but not in A549. The epithelial alveolar model with hAEpC combined with two immune cells (i.e. macrophages and dendritic cells) will offer a novel and more realistic cell co-culture system to study possible cell interactions of inhaled xenobiotics and their toxic potential on the human alveolar type I epithelial wall.

Early alveolar bone grafting has a negative effect on maxillary dental arch dimensions of pre-school children with complete unilateral cleft lip and palate

To evaluate maxillary dental arch dimensions in pre-school children with a complete unilateral cleft lip and palate (CUCLP) after early alveolar bone grafting.

Local strain distribution in real three-dimensional alveolar geometries

Mechanical ventilation is not only a life saving treatment but can also cause negative side effects. One of the main complications is inflammation caused by overstretching of the alveolar tissue. Previously, studies investigated either global strains or looked into which states lead to inflammatory reactions in cell cultures. However, the connection between the global deformation, of a tissue strip or the whole organ, and the strains reaching the single cells lining the alveolar walls is unknown and respective studies are still missing. The main reason for this is most likely the complex, sponge-like alveolar geometry, whose three-dimensional details have been unknown until recently. Utilizing synchrotron-based X-ray tomographic microscopy, we were able to generate real and detailed three-dimensional alveolar geometries on which we have performed finite-element simulations. This allowed us to determine, for the first time, a three-dimensional strain state within the alveolar wall. Briefly, precision-cut lung slices, prepared from isolated rat lungs, were scanned and segmented to provide a three-dimensional geometry. This was then discretized using newly developed tetrahedral elements. The main conclusions of this study are that the local strain in the alveolar wall can reach a multiple of the value of the global strain, for our simulations up to four times as high and that thin structures obviously cause hotspots that are especially at risk of overstretching.

Microfluidic wound-healing assay to assess the regenerative effect of HGF on wounded alveolar epithelium

We present a microfluidic epithelial wound-healing assay that allows characterization of the effect of hepatocyte growth factor (HGF) on the regeneration of alveolar epithelium using a flow-focusing technique to create a regular wound in the epithelial monolayer. The phenotype of the epithelial cell was characterized using immunostaining for tight junction (TJ) proteins and transmission electron micrographs (TEMs) of cells cultured in the microfluidic system, a technique that is reported here for the first time. We demonstrate that alveolar epithelial cells cultured in a microfluidic environment preserve their phenotype before and after wounding. In addition, we report a wound-healing benefit induced by addition of HGF to the cell culture medium (19.2 vs. 13.5 μm h(-1) healing rate).

Depletion of murine intestinal microbiota: effects on gut mucosa and epithelial gene expression

Background Inappropriate cross talk between mammals and their gut microbiota may trigger intestinal inflammation and drive extra-intestinal immune-mediated diseases. Epithelial cells constitute the interface between gut microbiota and host tissue, and may regulate host responses to commensal enteric bacteria. Gnotobiotic animals represent a powerful approach to study bacterial-host interaction but are not readily accessible to the wide scientific community. We aimed at refining a protocol that in a robust manner would deplete the cultivable intestinal microbiota of conventionally raised mice and that would prove to have significant biologic validity. Methodology/Principal Findings Previously published protocols for depleting mice of their intestinal microbiota by administering broad-spectrum antibiotics in drinking water were difficult to reproduce. We show that twice daily delivery of antibiotics by gavage depleted mice of their cultivable fecal microbiota and reduced the fecal bacterial DNA load by 400 fold while ensuring the animals' health. Mice subjected to the protocol for 17 days displayed enlarged ceca, reduced Peyer's patches and small spleens. Antibiotic treatment significantly reduced the expression of antimicrobial factors to a level similar to that of germ-free mice and altered the expression of 517 genes in total in the colonic epithelium. Genes involved in cell cycle were significantly altered concomitant with reduced epithelial proliferative activity in situ assessed by Ki-67 expression, suggesting that commensal microbiota drives cellular proliferation in colonic epithelium. Conclusion We present a robust protocol for depleting conventionally raised mice of their cultivatable intestinal microbiota with antibiotics by gavage and show that the biological effect of this depletion phenocopies physiological characteristics of germ-free mice.