Apical Migration Research Articles

Micropattern-mediated apical guidance accelerates epithelial cell migration to improve healing around percutaneous gastrostomy tubes

Hypergranulation, bacterial infection, and device dislodgment are common complications associated with percutaneous gastronomy (PG) tube placement for enteral feeding largely attributable to delayed stoma tract maturation around the device. Stoma tract maturation is a wound-healing process that requires collective and complete migration of an advancing epithelial layer. While it is widely accepted that micropatterned surfaces enhance cell migration when cells are cultured directly on the substrate, few studies have investigated the influence of apical contact guidance from micropatterned surfaces on cell migration, as occurs during stoma tract formation. Here, we developed 2D and 3D in vitro epithelial cell migration assays to test the effect of various Sharklet micropatterns on apically-guided cell migration. The 2D modified scratch wound assay identified a Sharklet micropattern (+10SK50×50) that enhanced apical cell migration by 4-fold (p = 0.0105) compared to smooth controls over the course of seven days. The best-performing micropattern was then applied to cylindrical prototypes with the same outer diameter as a pediatric PG tube. These prototypes were evaluated in the novel 3D migration assay where magnetic levitation aggregated cells around prototypes to create an artificial stoma. Results indicated a 50% increase (p < 0.0001) in cell migration after seven days along Sharklet-micropatterned prototypes compared to smooth controls. The Sharklet micropattern enhanced apically-guided epithelial cell migration in both 2D and 3D in vitro assays. These data suggest that the incorporation of a Sharklet micropattern onto the surface of a PG tube may accelerate cell migration via apical contact, improve stoma tract maturation, and reduce skin-associated complications.

Differences in effectiveness of membrane fixation using periosteal vertical mattress and simple sling suture techniques in infrabony pocket treatment

Guide tissue regeneration (GTR) is the treatment of infrabony pockets for soft and hard tissue regeneration. Membrane is used as a barrier and prevents apical migration of the cells in epithelial tissues. Membrane fixation is one of the procedures in GTR treatment because resorbed membrane is less stable. Simple sling suture technique for membrane fixation has 1 anchorage, located in coronal flap, while periosteal vertical mattress suture technique has 2 anchorages in periosteum, making it more stable. This study aimed to study the differences in the effectiveness of membrane fixation using periosteal vertical mattress suture and simple sling suture techniques in terms of probing depth, relative attachment loss, and alveolar bone height in the treatment of infrabony pockets. The samples were divided into 2 groups. The first group was open flap debridement (OFD) with demineralized freeze dried bone allograft (DFDBA) application and membrane fixation with simple sling suture, while the second group was OFD with DFDBA application and membrane fixation with periosteal vertical mattress suture, observed on day 0, 30th day, and 90th day. The results of the study showed significant differences in the probing depth and relative attachment loss (except from the 30th day to the 90th day), and there were no significant differences in the alveolar bone height from the baseline to the 90th day, between the group of membrane fixation using simple sling suture and that of periosteal vertical mattress suture techniques on flap surgery. This study concluded that membrane fixation in the treatment of infrabony pocket with periosteal vertical mattress suture technique is more effective in reducing the probing depth and relative attachment loss, but there is no difference in increasing the alveolar bone height when compared to simple sling suture technique.

Prevalence of Altered Passive Eruption in UCSG Dental students

The dental eruption is a physiological process that is divided into two phases: active and passive. An alteration in the passive phase will result in an altered passive eruption (EPA), which would be defined as the interruption of the apical migration of the margin of the gingiva, where it moves away from the amelocementary limit. This can be classified into 2 groups and 2 subgroups: 1A, 1B, 2A and 2B. Its importance lies in its diagnosis and treatment, since it is responsible for a large part of the consultations for restorative treatments due to the alterations that can produce in the aesthetics of the smile due to its clinical signs: short teeth, absence of gingival scallopings, and gingival smile Materials and Methods: A cross-sectional descriptive and analytical study where 100 UCSG odontology students were randomly selected according to the inclusion and exclusion criteria. The prevalence of altered passive eruption and its types was determined by the T Bar, a periodontal probe and periapical radiographs. Results: 100 subjects, 35 men and 65 women were analyzed. 16% of the subjects had EPA, of which 19% 1A and 81% 1B. The prevalence of high smile in people with short teeth was 37.5% and 31.25% in middle and low smiles. The variables of ethnicity and genetics were irrelevant. The EPA had a low prevalence of 16%, being more prevalent in women. I had no direct relation to the type of smile.

Sun1 Mediates Interkinetic Nuclear Migration and Notch Signaling in the Neurogenesis of Zebrafish.

Interkinetic nuclear migration (INM) is a process by which nuclei oscillate between the basal and apical surfaces of epithelial cells in coordination with the cell cycle. The cytoskeletal machinery including microtubules and actin has been reported to drive apical INM; however, the role of nuclear proteins in this process has yet to be fully elucidated. Here, we investigated the function of a SUN-domain protein, Sun1, in zebrafish. We found that zebrafish sun1 is highly expressed in the ventricular zone of the brain. Knocking down sun1 with antisense morpholino oligonucleotides reduced the abundance of nestin- and gfap-expressing neural stem cells and progenitor cells. The live-cell imaging results showed that sun1 morphant cells migrated toward the basal side during the S phase but failed to migrate apically during the G2 phase. On the contrary, the passive stochastic movement during the G2 phase was unaffected. Furthermore, down regulation of sun1 was shown to reduce the expression of genes associated with the Notch pathway, whereas the expression of genes in the Wnt pathway was less perturbed. Findings from this research suggest that the Sun1-mediated nucleo-cytoskeletal interaction contributes to apical nuclear migration, and may thus affect exposure to Notch signal, thereby altering the composition of the progenitor pool in the embryonic neurogenesis of zebrafish.

Gingival recession and periodontal therapy

Background: Gingival recession is defined as the apical migration of the gingival margin below the cementoenamel junction (CEJ), resulting in exposure of the root surface and it is one of the main esthetic complaints of patients. The management of gingival recession and its sequelae is based on a thorough assessment of the etiological factors and the degree of tissue involvement.

Sialomucin CD43 regulates T helper type 17 cell intercellular adhesion molecule 1 dependent adhesion, apical migration and transendothelial migration.

T helper type 17 lymphocytes (Th17 cells) infiltrate the central nervous system (CNS), induce inflammation and demyelination and play a pivotal role in the pathogenesis of multiple sclerosis. Sialomucin CD43 is highly expressed in Th17 cells and mediates adhesion to endothelial selectin (E-selectin), an initiating step in Th17 cell recruitment to sites of inflammation. CD43-/- mice have impaired Th17 cell recruitment to the CNS and are protected from experimental autoimmune encephalomyelitis (EAE), the mouse model of multiple sclerosis. However, E-selectin is dispensable for the development of EAE, in contrast to intercellular and vascular cell adhesion molecules (ICAM-1 and VCAM-1). We report that CD43-/- mice have decreased demyelination and T-cell infiltration, but similar up-regulation of ICAM-1 and VCAM-1 in the spinal cord, compared with wild-type (WT) mice, at the initiation of EAE. CD43-/- Th17 cells have impaired adhesion to ICAM-1 under flow conditions invitro, despite having similar expression of LFA-1, the main T-cell ligand for ICAM-1, as WT Th17 cells. Regardless of the route of integrin activation, CD43-/- Th17 cell firm arrest on ICAM-1 was comparable to that of WT Th17 cells, but CD43-/- Th17 cells failed to optimally apically migrate on immobilized ICAM-1-coated coverslips and endothelial cells, and to transmigrate under shear flow conditions in an ICAM-1-dependent manner. Collectively, these findings unveil novel roles for CD43, facilitating adhesion of Th17 cells to ICAM-1 and modulating apical and transendothelial migration, as mechanisms potentially responsible for Th17 cell recruitment to sites of inflammation such as the CNS.

Distinct roles for dynein light intermediate chains in neurogenesis, migration, and terminal somal translocation.

Cytoplasmic dynein participates in multiple aspects of neocortical development. These include neural progenitor proliferation, morphogenesis, and neuronal migration. The cytoplasmic dynein light intermediate chains (LICs) 1 and 2 are cargo-binding subunits, though their relative roles are not well understood. Here, we used in utero electroporation of shRNAs or LIC functional domains to determine the relative contributions of the two LICs in the developing rat brain. We find that LIC1, through BicD2, is required for apical nuclear migration in neural progenitors. In newborn neurons, we observe specific roles for LIC1 in the multipolar to bipolar transition and glial-guided neuronal migration. In contrast, LIC2 contributes to a novel dynein role in the little-studied mode of migration, terminal somal translocation. Together, our results provide novel insight into the LICs' unique functions during brain development and dynein regulation overall.

Use of Vestibular Incision Subperiosteal Tunnel Access Technique with Platelet Rich Fibrin in the Treatment of Miller Class I Gingival Recession: A Case Report

Gingival recession is defined as apical migration of gingival margins resulting in exposure of the root surface. It can be either localized or generalized, involving one or more than 1 surfaces and there by leading to functional & esthetic problems like hypersensitivity, cervical abrasions & root caries. Various techniques have been developed to achieve root coverage. The current case report describes treatment of multiple class I gingival recession using vestibular incision sub periosteal tunnel access (VISTA) technique and platelet rich fibrin (PRF) membrane. Position of gingiva was maintained using coronally anchored sutures during initial healing period. The use of PRF membrane along with the VISTA allows clinicians to successfully treat multiple gingival recession defects.

Live imaging of developing mouse retinal slices

BackgroundEx vivo, whole-mount explant culture of the rodent retina has proved to be a valuable approach for studying retinal development. In a limited number of recent studies, this method has been coupled to live fluorescent microscopy with the goal of directly observing dynamic cellular events. However, retinal tissue thickness imposes significant technical limitations. To obtain 3-dimensional images with high quality axial resolution, investigators are restricted to specific areas of the retina and require microscopes, such as 2-photon, with a higher level of depth penetrance. Here, we report a retinal live imaging method that is more amenable to a wider array of imaging systems and does not compromise resolution of retinal cross-sectional area.ResultsMouse retinal slice cultures were prepared and standard, inverted confocal microscopy was used to generate movies with high quality resolution of retinal cross-sections. To illustrate the ability of this method to capture discrete, physiologically relevant events during retinal development, we imaged the dynamics of the Fucci cell cycle reporter in both wild type and Cyclin D1 mutant retinal progenitor cells (RPCs) undergoing interkinetic nuclear migration (INM). Like previously reported for the zebrafish, mouse RPCs in G1 phase migrated stochastically and exhibited overall basal drift during development. In contrast, mouse RPCs in G2 phase displayed directed, apical migration toward the ventricular zone prior to mitosis. We also determined that Cyclin D1 knockout RPCs in G2 exhibited a slower apical velocity as compared to wild type. These data are consistent with previous IdU/BrdU window labeling experiments on Cyclin D1 knockout RPCs indicating an elongated cell cycle. Finally, to illustrate the ability to monitor retinal neuron differentiation, we imaged early postnatal horizontal cells (HCs). Time lapse movies uncovered specific HC neurite dynamics consistent with previously published data showing an instructive role for transient vertical neurites in HC mosaic formation.ConclusionsWe have detailed a straightforward method to image mouse retinal slice culture preparations that, due to its relative ease, extends live retinal imaging capabilities to a more diverse group of scientists. We have also shown that, by using a slice technique, we can achieve excellent lateral resolution, which is advantageous for capturing intracellular dynamics and overall cell movements during retinal development and differentiation.

BDNF/HMW-HA complex as an adjunct to nonsurgical periodontal treatment of ligature-induced periodontitis in dogs.

Recently, brain-derived neurotrophic factor (BDNF)/high molecular weight hyaluronic acid (HMW-HA) complex with flap surgery has been shown to promote periodontal tissue regeneration. The objective of this study was to evaluate the effects of local subgingival application of BDNF/HMW-HA complex adjunctive to scaling and root planning (SRP) on ligature-induced periodontitis in dogs. The dogs were divided into four treatment groups: no treatment (control), SRP alone, SRP followed by local application of HMW-HA (SRP+HMW-HA), and SRP followed by local application of BDNF (500μg/ml)/ HMW-HA complex (SRP+BDNF/HMW-HA). HMW-HA or BDNF/HMW-HA complex was topically applied to periodontal pockets using a syringe without surgery. Two weeks after treatment, clinical parameters (gingival index, clinical attachment level, periodontal pocket depth and bleeding on probing) were recorded and specimens were collected from anesthetized animals for histological analysis. The SRP+BDNF/HMW-HA group showed significant improvement in all clinical parameters compared to other treatment groups. Histologic analysis showed greater suppression of apical migration of epithelial tissue and milder inflammatory cell infiltration in the SRP+BDNF/HMW-HA group than in the other treatment groups. Furthermore, new cementum and alveolar bone were regenerated, and collagen fibers were inserted into them in the SRP+BDNF/HMW-HA group. BDNF/HMW-HA complex as an adjunct to nonsurgical periodontal treatment has the potential to reduce excess inflammation. Further investigation will be needed to clarify periodontal tissue regenerative effects of BDNF/HMW-HA complex in a nonsurgical setting.

Study of pallial neurogenesis in shark embryos and the evolutionary origin of the subventricular zone

The dorsal part of the developing telencephalon is one of the brain areas that has suffered most drastic changes throughout vertebrate evolution. Its evolutionary increase in complexity was thought to be partly achieved by the appearance of a new neurogenic niche in the embryonic subventricular zone (SVZ). Here, a new kind of amplifying progenitors (basal progenitors) expressing Tbr2, undergo a second round of divisions, which is believed to have contributed to the expansion of the neocortex. Accordingly, the existence of a pallial SVZ has been classically considered exclusive of mammals. However, the lack of studies in ancient vertebrates precludes any clear conclusion about the evolutionary origin of the SVZ and the neurogenic mechanisms that rule pallial development. In this work, we explore pallial neurogenesis in a basal vertebrate, the shark Scyliorhinus canicula, through the study of the expression patterns of several neurogenic markers. We found that apical progenitors and radial migration are present in sharks, and therefore, their presence must be highly conserved throughout evolution. Surprisingly, we detected a subventricular band of ScTbr2-expressing cells, some of which also expressed mitotic markers, indicating that the existence of basal progenitors should be considered an ancestral condition rather than a novelty of mammals or amniotes. Finally, we report that the transcriptional program for the specification of glutamatergic pallial cells (Pax6, Tbr2, NeuroD, Tbr1) is also present in sharks. However, the segregation of these markers into different cell types is not clear yet, which may be linked to the lack of layering in anamniotes.

Evaluation of maxillary buccal alveolar bone before and after orthodontic alignment without extractions: A cone beam computed tomographic study.

To assess the changes in the maxillary buccal alveolar bone during alignment without extractions. Secondarily, to evaluate the changes in arch dimensions and buccolingual inclinations of teeth and to identify risk factors for bone loss. Twenty-two adolescents with crowded permanent dentitions were treated without extractions with Damon 3MX brackets. Cone beam computed tomographic scans were taken before treatment (T0) and after alignment (T1). Bone thickness (BT) and height from the cementoenamel junction to the alveolar crest (BH) were evaluated at the maxillary central incisors, second premolars, and buccal roots of first molars. Changes in all variables from T0 to T1 were assessed. Correlations between bone changes and initial bone thickness, initial arch widths, initial crowding, amount of expansion, amount of tipping, and amount of molar rotation were calculated. BT decreased and BH increased significantly for the incisors and mesiobuccal root of the first molars. Arch dimensions generally increased together with tipping. Bone loss was correlated with crowding and amount of expansion in the premolar region. Initially thinner BT was correlated with greater apical migration of bone for the incisors. Nonextraction alignment with self-ligating brackets led to arch expansion associated with tipping of teeth. Expansion related to alignment resulted in horizontal and vertical bone loss at the incisors and mesiobuccal root of the first molars. Thinner BTs and more severe crowding before treatment increased the risk for buccal bone loss.

Pseudomonas aeruginosa-induced lung epithelial production of IL-8 contributes to PMN sub-mucosa recruitment but not trans-epithelial migration in vitro.

Abstract Background Numerous lung associated diseased states such as acute pneumonia and cystic fibrosis (CF) are associated with increased concentrations of IL8 and infiltration of neutrophils (PMNs) in the airspace. IL8 production by lung epithelial cells (ECs) is stimulated by Pseudomonas aeruginosa infection, an opportunistic pathogen involved in acute pneumonia, and lung infection of CF patients. The exact role IL8 plays in migration of circulating PMNs into the infected lung and airspace is still uncertain. Objective Assess the role of IL8 in mediating PMN migration in response to P. aeruginosa infected lung epithelium. Methods CRISPR/Cas9 was used to delete the IL8 gene from human lung ECs, which were grown as polarized monolayers in a co-culture transwell model. Basolateral to apical PMN migration to PAO1 infection was assessed. A novel double transwell model was developed to observe PMN submucosa migration in response to PAO1 infection in the presence and absence of IL8 lung EC production. Results PAO1 induced PMN trans-epithelial (TE) migration was not impacted in the absence of IL8 expression. When PMNs were placed in a separate transwell suspended 5 mm above the basolateral side of the infected epithelium, the IL8 gradient produced was sufficient to cause relevant migration of PMNs to the basolateral side of the infected epithelium. The level of migrated PMNs in the double transwell system with tissues devoid of the IL8 gene was equivalent to the presence of PMNs which responded to un-infected epithelial tissues. Conclusion These findings further support that IL8 is integral in PMN recruitment, and suggests that IL8 is most important towards recruiting PMNs to the submucosa during P. aeruginosa PAO1 infection of lung epithelium.

Exploring the Gingival Recession Surgical Treatment Modalities: A Literature Review.

Gingival recessions present complex soft tissue pathology, with a multiple aetiology and a high prevalence which increases with age. They are defined as an exposure of the root surface of the teeth as a result of the apical migration of the gingival margin beyond the cementum-enamel junction, causing functional and aesthetic disturbances to the affected individuals. Aiming to ensure complete root coverage and satisfying aesthetic outcomes, a wide range of surgical techniques have been proposed through the decades for the treatment of the gingival recessions. The following literature review attempts to provide a comprehensive, structured and up-to-date summary of the relevant literature regarding these surgical techniques, aiming to emphasise for each technique its indications, its long-term success and predictability, its advantages and disadvantages about each other.

Systematic review of the effects of excessive occlusal mechanical load on the periodontum of rats.

This study aims to systematically evaluate the effects of traumatic occlusion on the periodontal tissue of rats. The set of questions to be answered were-Can traumatic occlusion acting on a healthy and an unhealthy periodontium cause periodontal destruction? The protocols for systematic review were all developed, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement and applied to animal research. Reporting of In vivo experiment guidelines for reporting animal research to assess the risk of bias of the studies. A literature search was conducted using MEDLINE through PubMed and manual search from the reference lists of main articles related to the theme. This search strategy identified 65 references, of which 33 were considered inappropriate. The full texts of 32 articles were read, 31 of which did not meet the eligibility criteria and were excluded. The final selection included 1 article for which data was extracted for further evaluation. The article included shows a strongest reaction in the periodontium in front of a secondary occlusal trauma as inflammation and apical migration of the junctional epithelium, bone degradation, and decrease in the quantity of collagen fiber. However, primary occlusal trauma also presents these alterations, with the exception of apical migration of the junctional epithelium. Although only one study was included in the systematic review of traumatic occlusion, there is some evidence from experimental studies on animals that shows a coherent picture of the effects of traumatic occlusion on the periodontium. However, new studies are needed to fully answer the questions posed by this systematic review.

Management of miller class II gingival recession by laterally positioned pedicle flap revised technique

Background and objective: Gingival recession is the apical migration of the gingival margin from its normal position on the crown of the tooth to the root apically beyond the cemento-enamel junction which can cause major functional and esthetical problems. It has been clinically related to higher incidence of root caries, attachment loss, hypersensitivity and esthetic related problems. The goal of this study was to evaluate the effective of a modification of surgical procedure to laterally repositioned flap for coverage of isolated recession. Methods: A total of 25 patients with miller class II gingival recession attended the Department of Periodontology in the College of Dentistry, Hawler Medical University for treatment of their problem. Their gingival recession about 2 to 5mm in the lower anterior teeth with shallow vestibule. After full preparation of patient which include scaling and polishing and root planning the laterally displaced revised flap technique were done. Patients were followed up in 2 week and 3 month interval to see the changes after treatment during this period. These parameter were taken pocket depth, clinical attachment loss and gingival recession which can be measured by the distance from CEJ to the base of pocket. Result: In the recipient side, the mean gingival recession was about 3.2 mm at base line, after 2 weeks the mean gingival recession became 0.6mm and after 3 months it became 0.38mm. In the donor side, the mean gingival recession was 0 mm at base line. After 2 weeks the mean gingival recession became 1.05mm and after 3 months it became 0.5mm. Conclusion: It can be concluded that laterally displaced revised flap technique in localized recession defects can be used to restore the esthetic and functional properties of labial gingiva of teeth by repairing gingival defect.

Management of Gingival Recession Using Laterally Repositioned Flap—A Case Report

AbstractGingival recession is defined as apical migration of gingival margin in relation to cement enamel junction. The laterally repositioned flap is used to cover denuded root surface that has adequate donor tissue laterally as well as adequate vestibular depth. This article highlights the use of laterally repositioned flap for the management of localized Miller's Class II gingival recession. An excellent esthetic outcome was achieved and patient was satisfied with case resolution.

A Multifunctional Polymeric Periodontal Membrane with Osteogenic and Antibacterial Characteristics

AbstractPeriodontitis is a prevalent chronic, destructive inflammatory disease affecting tooth‐supporting tissues in humans. Guided tissue regeneration strategies are widely utilized for periodontal tissue regeneration generally by using a periodontal membrane. The main role of these membranes is to establish a mechanical barrier that prevents the apical migration of the gingival epithelium and hence allowing the growth of periodontal ligament and bone tissue to selectively repopulate the root surface. Currently available membranes have limited bioactivity and regeneration potential. To address such challenges, an osteoconductive, antibacterial, and flexible poly(caprolactone) (PCL) composite membrane containing zinc oxide (ZnO) nanoparticles is developed. The membranes are fabricated through electrospinning of PCL and ZnO particles. The physical properties, mechanical characteristics, and in vitro degradation of the engineered membrane are studied in detail. Also, the osteoconductivity and antibacterial properties of the developed membrane are analyzed in vitro. Moreover, the functionality of the membrane is evaluated with a rat periodontal defect model. The results confirmed that the engineered membrane exerts both osteoconductive and antibacterial properties, demonstrating its great potential for periodontal tissue engineering.

Microtubule stabilization drives 3D centrosome migration to initiate primary ciliogenesis.

Primary cilia are sensory organelles located at the cell surface. Their assembly is primed by centrosome migration to the apical surface, yet surprisingly little is known about this initiating step. To gain insight into the mechanisms driving centrosome migration, we exploited the reproducibility of cell architecture on adhesive micropatterns to investigate the cytoskeletal remodeling supporting it. Microtubule network densification and bundling, with the transient formation of an array of cold-stable microtubules, and actin cytoskeleton asymmetrical contraction participate in concert to drive apical centrosome migration. The distal appendage protein Cep164 appears to be a key actor involved in the cytoskeleton remodeling and centrosome migration, whereas intraflagellar transport 88's role seems to be restricted to axoneme elongation. Together, our data elucidate the hitherto unexplored mechanism of centrosome migration and show that it is driven by the increase and clustering of mechanical forces to push the centrosome toward the cell apical pole.

Coronally advanced flap as a root coverage procedure in treatment of class I gingival recession defects - A report of two cases

AbstractGingival recession is defined as the apical migration of the gingival margin beyond the cementenamel junction (CEJ). This results in the exposure of tooth roots which is aesthetically unpleasing and can also result in tooth hypersensitivity. A number of surgical procedures have been used to obtain root coverage. The aim of the present article was to evaluate the coverage of labial gingival recession defects with coronally advanced flap procedure in two cases with labial gingival recession.Two male patients (32 year and 52 year old) were treated for root coverage with coronally advanced flap in maxillary right first molar (16), second premolar (15) and maxillary left incisor (22) and canine (23) region respectively.In both the cases, root coverage of the labial recession defects was observed.