Gingival depigmentation with scalpel and diode laser

Melanin, a nonhemoglobin-derived brown pigment, is the most common of the endogenous pigments and is produced by melanocytes present in the basal layer of the epithelium. Gingival hyperpigmentation is caused by excessive deposition of melanin located in the basal and suprabasal cell layers of the epithelium. Pigmentation of gingiva not just has an impact on esthetics but also creates psychological negativity. Though a wide range of techniques are available to manage this condition. Depigmentation procedures such as scalpel surgery, gingivectomy with free gingival autografting, electrosurgery, cryosurgery, chemical agents such as 90% phenol and 95% alcohol, abrasion with diamond bur, Nd: YAG laser, semiconductor diode laser, and CO laser have been employed for removal of melanin hyper pigmentation. The following case report describes two different surgical depigmentation techniques scalpel technique and lasers. Better results of depigmentation were achieved with diode laser than conventional scalpel with respect to esthetics and less postoperative discomfort.

Interleukin-17A pathway target genes are upregulated in Equus caballus supporting limb laminitis

Supporting Limb Laminitis (SLL) is a painful and crippling secondary complication of orthopedic injuries and infections in horses, often resulting in euthanasia. SLL causes structural alterations and inflammation of the interdigitating layers of specialized epidermal and dermal tissues, the lamellae, which suspend the equine distal phalanx from the hoof capsule. Activation of the interleukin-17A (IL-17A)-dependent inflammatory pathway is an epidermal stress response that contributes to physiologic cutaneous wound healing as well as pathological skin conditions. As a first test of the hypothesis that hoof lamellae of horses diagnosed with SLL also respond to stress by activating the IL-17A pathway, the expression of IL-17A, IL-17 receptor subunit A and 11 IL-17A effector genes was measured by RT-PCR or qPCR. Lamellar tissue was isolated from Thoroughbreds euthanized due to naturally occurring SLL and in age and breed matched non-laminitic controls. By RT-PCR, the IL-17 Receptor A subunit was expressed in both non-laminitic and laminitic tissues, while IL-17A was primarily detectable in laminitic tissues. IL-17A target gene expression was undetectable in non-laminitic samples with the exception of weak detection of DEFB4B, S100A9 and PTSG2. In contrast, all target genes examined, except CCL20, were expressed by some or all laminitic samples. By qPCR, severe acute (n = 7) SLL expressed ~15–100 fold higher levels of DEFB4B and S100A9 genes compared to non-laminitic controls (n = 8). DEFB4B was also upregulated in developmental/subclinical (n = 8) and moderate acute (n = 7) by ~ 5-fold, and in severe chronic (n = 5) by ~15–200 fold. In situ hybridization (DEFB4) and immunofluorescence (calprotectin, a dimer of S100A9/S100A8 proteins) demonstrated expression in keratinocytes, primarily in suprabasal cell layers, from SLL samples. These data demonstrate upregulation of a cohort of IL-17A target genes in SLL and support the hypothesis that similarities in the response to stresses and damage exist between equine and human epidermal tissues.

Epidermal stratification is uncoupled from centrosome-dependent cell division orientation of the basal progenitors

The development of complex stratified epithelial barriers in mammals is initiated from single-layered epithelia. How stratification is initiated and fueled are still open questions. Previous studies on skin epidermal stratification suggested a central role for perpendicular/asymmetric cell division orientations of the basal keratinocyte progenitors. Here, we use centrosomes, that organize the mitotic spindle, to test whether cell division orientations and stratification are linked. Genetically ablating centrosomes from the developing epidermis led to the activation of the p53-, 53BP1- and USP28-dependent mitotic surveillance pathway causing a thinner epidermis and hair follicle arrest. Importantly, the centrosome/p53 double mutant keratinocyte progenitors significantly altered their division orientations without affecting epidermal stratification. Time-lapse imaging and tissue growth dynamic measurements suggested that early stratification is initiated by a burst in basal and suprabasal cell proliferation as well as cell delamination. The data provide insights for tissue homeostasis and hyperproliferative diseases that may recapitulate developmental programs.

Interleukin-17 pathway activation in Equus caballus supporting limb laminitis

Supporting Limb Laminitis (SLL) is a painful and crippling secondary complication of orthopedic injuries and infections in horses, often resulting in euthanasia. Due to altered weight bearing, SLL causes structural alternations and inflammation of the interdigitating layers of specialized epidermal and dermal tissues, the lamellae, which suspend the equine distal phalanx from the hoof capsule. Activation of the interleukin-17 (IL-17)-dependent inflammatory pathway is an epidermal stress response that contributes to physiologic cutaneous wound healing as well as pathological skin conditions. To test the hypothesis that IL-17 pathway activation is involved in equine epidermal lamellae in SLL, we analyzed the expression of the IL-17 receptor subunit A and 11 genes upregulated by IL-17 in lamellar tissue isolated from Thoroughbreds euthanized due to naturally occurring SLL and in age and breed matched non-laminitic controls. The IL-17 Receptor A subunit was expressed in both non-laminitic and laminitic tissues. In severe acute SLL (n=7) compared to non-laminitic controls (n=8), quantitative PCR demonstrated ∼20-100 fold upregulation of ß defensin 4 (E. caballus gene DEFB4B) and S100A9 genes. DEFB4B was also upregulated in developmental (n=8), moderate acute (n=7), and severe chronic (n=5) samples. By RT-PCR, S100A8, MMP9, and PTSG2 (COX2) expression was upregulated in most or all severe acute SLL samples, whereas several other genes, CCL2, CxCL8, TNFα, IL6 and MMP1 were detected in some, but not all, severe acute samples. PTGS2, CCL2, TNFα and IL6 were also expressed in some, but not all, developmental and moderate acute disease stages. Moreover, expression of DEFB4 by in situ hybridization and calprotectin (S100A9/S100A8) protein by immunofluorescence was detected in keratinocytes, primarily in suprabasal cell layers, from SLL samples. These data support the hypothesis that the IL-17 inflammatory pathway is active in equine SLL, and that similarities exist between equine and human epidermal tissue responses to stresses and/or damage.

Assessment of Proliferative Potential of Odontogenic Keratocyst and Dentigerous Cyst using Podoplanin: An Immunohistochemical Study

ABSTRACT Introduction Odontogenic cysts are commonly encountered lesions among head and neck pathologies. Odontogenic keratocyst (OKC) has unique features of recurrence and local aggressiveness. Podoplanin (PDP) is a lymphatic endothelial marker and is shown to be expressed in a variety of tissues. Hence, we planned to assess the significance of PDP in OKC and dentigerous cyst (DC). Materials and methods The present study included assessment of immunoexpression of PDP in OKC and DC. Twenty specimens each of OKC and DC were included in the present study and were stained with D2-40 antibody. All the sections were analyzed and were categorized as negative staining, weakly positive staining, and strongly positive staining. All the results were analyzed by Statistical Package for the Social Sciences (SPSS) software. Results We detected PDP-positive staining in the cell membrane and cytoplasm of the cells of basal cell layer and suprabasal cell layers. In DC cases, we observed positive staining only in cases associated with inflammation. Conclusion Podoplanin does play a significant role in enhancing the local invasive and neoplastic properties of OKC. Clinical significance Podoplanin expression in OKC is potentially associated with moderate invasive nature of the neighboring structures. How to cite this article Gupta S, Paliwal A, Choudaha N, Gupta A, Rao P, Grover S. Assessment of Proliferative Potential of Odontogenic Keratocyst and Dentigerous Cyst using Podoplanin: An Immunohistochemical Study. J Contemp Dent Pract 2017;18(12):1173-1176.

KGF promotes integrin α5expression through CCAAT/enhancer-binding protein-β

Keratinocyte growth factor (KGF) and α5β1-integrin are not expressed in normal skin but they are both highly upregulated in the migrating epidermis during wound healing. Here we report that KGF increased α5mRNA and protein levels in epidermoid carcinoma cells and stratified bioengineered epidermis. Interestingly, KGF increased integrin α5in the basal as well as suprabasal cell epidermal layers. Promoter studies indicated that KGF-induced integrin α5promoter activation was dependent on the C/EBP transcription factor binding site. Accordingly, KGF induced sustained phosphorylation of C/EBP-β that was dependent on activation of ERK1/2. In addition, a dominant negative form of C/EBP-β inhibited α5promoter activity and blocking C/EBP-β with siRNA diminished integrin α5expression. Taken together, our data indicate that KGF increased integrin α5expression by phosphorylating C/EBP-β. Interestingly, KGF-induced upregulation of integrin α5was more pronounced in three-dimensional tissue analogues than in conventional two-dimensional culture suggesting that stratified epidermis may be useful in understanding the effects of growth factors in the local tissue microenvironment.

Regulation of epidermal differentiation by a Distal-less homeodomain gene.

The Distal-less-related homeodomain gene Dlx3 is expressed in terminally differentiated murine epidermal cells. Ectopic expression of this gene in the basal cell layer of transgenic skin results in a severely abnormal epidermal phenotype and leads to perinatal lethality. The basal cells of affected mice ceased to proliferate, and expressed the profilaggrin and loricrin genes which are normally transcribed only in the latest stages of epidermal differentiation. All suprabasal cell types were diminished and the stratum corneum was reduced to a single layer. These data indicate that Dlx3 misexpression results in transformation of basal cells into more differentiated keratinocytes, suggesting that this homeoprotein is an important regulator of epidermal differentiation.

Expression of proteoglycans and hyaluronan during wound healing.

We investigated the expression of proteoglycans (PGs) and hyaluronan (HA) during healing of human mucosal wounds. Biopsy specimens of experimental wounds were taken 1, 3, and 7 days after wounding. Frozen sections were used for immunolocalization of CD44, syndecan-1, basement membrane-associated heparan sulfate proteoglycan (BM-HSPG), decorin, and biglycan. HA was localized in paraffin sections with a specific HA-binding probe. Epithelium showed first signs of migration on Day 1, more progressive migration on Day 3, and epithelial sheets confronted on Day 7. CD44 surrounded migrating keratinocytes at all stages of wound healing. In epithelium, CD44 and HA remarkably localized to the same region. Expression of syndecan-1 was switched from the suprabasal cell layer of unwounded epithelium to the basal cell layer of the migrating wound epithelium. BM-HSPG was absent under migrating keratinocytes. It started to reappear at the basement membrane zone on Day 7. The area under the wound epithelium containing newly synthesized collagen fibers first became positive for decorin on Day 7, whereas staining of biglycan was negative. Granulation tissue was also strongly positive for CD44 and hyaluronan. Our results indicate that migrating keratinocytes express both CD44 and syndecan-1 but not BM-HSPG. During differentiation of keratinocytes, expression of CD44 preceded that of syndecan-1. The results suggest that different HSPGs have multiple functions in keratinocyte migration and differentiation during reepithelialization.