Influence of suturing material on wound healing: Experimental study in dogs

Background/Aim. The most common materials implanted in the human organism are suture materials that are classified on the basis of several criteria, usually the origin, structure, and properties. The properties of suture materials are related to its absorbability and non-absorbability. When using resorbable materials it is of great importance to determine whether its absorbability and tensile strength help wound healing in function of time. Sutures themselves can become a source of inflammation, that may reduce or compromise the potential of reparation and regeneration. The aim of this experimental study on dogs was to ascertain whether the absorption rate and the degree of local tissue reactions differ from information provided by the manufacturers, whether there are differences between the applied suture materials and which of the used suture materials have better effect on wound healing. Methods. Experimental testing of the selected suture materials basic characteristics was performed on 6 German Shepherd dogs, which, after induction of general anesthesia, were made 3 identical incisions each in all 4 quadrants (left and right side of the upper and lower jaws), so that 12 horizontal incisions were formed, 10 mm long, 20-25 mm distant from one another, on each animal. Randomly, incisions were stitched up in the following order, starting from back to front: catgut, Dexon?, Vicryl-Rapid?. The experiment was terminated by histopathological examination of tissue samples, taken on postoperative day 3, 7, 14 and 21 in order to identify the effect of healing and the degree of local reaction. Results. The obtained results suggest that catgut has the highest absorption rate, while Dexon? the lowest. Vicryl-Rapid? causes the lowest level of local reactions, while Dexon? the highest. Conclusion. There is no ideal suture material because various patient factors also influence the wound healing process.

Immunomodulatory Activity of IL-27 in Human Periapical Lesions

IL-27, a cytokine with pro-inflammatory and anti-inflammatory properties, is a new member of the IL-6/IL-12 family, whose function in periapical lesions is unknown. We hypothesized that the production of IL-27 and its effect depend upon the type of immune/inflammatory response and clinical presentation of periapical lesions. We tested this hypothesis by studying the expression and function of IL-27 in human periapical lesions, both in situ and in culture. Immunohistochemistry demonstrated the strongest expression of IL-27 by endothelial cells and mononuclear phagocytes. Its production by periapical lesion mononuclear cells (PL-MNC), especially in symptomatic lesions, was significantly higher compared with that in peripheral blood MNC and correlated with the frequency of CD14+ and CD3+ cells. Exogenous IL-27 stimulated Th1 and down-regulated Th17 cytokine production by PL-MNC from symptomatic lesions, but down-regulated Th1 and Th2 responses in asymptomatic lesions. These findings suggest that IL-27 is an immunomodulatory cytokine in periapical lesions, with complex biological effects.

Regulatory T-cells in Periapical Lesions

CD4+CD25hiFoxp3+ regulatory T-cells (Tregs) are of crucial importance in regulating the immune response, including the control of any defense against infection. Their presence in periapical lesions has not been demonstrated, as yet. We hypothesized that Tregs infiltrate periapical lesions, where they inhibit T-cell proliferation. The aim of this study was to characterize Tregs in periapical lesions by confocal microscopy, flow cytometry, and functional assays. We showed that CD4+CD25hiFoxp3+ cells in periapical lesions expressed IL-10 and TGF-β. Their frequency was significantly higher than in peripheral blood and correlated with the levels of TGF-β and IL-10 in culture supernatants of periapical lesion mononuclear cells. Tregs inhibited the proliferation of responder T-cells in vitro, at least in part, by stimulating the production of IL-10. These findings suggest that CD4+CD25hiFoxp3+ cells in periapical lesions may play regulatory roles in controlling local immune/inflammatory processes.

Interleukin-17 plays a role in exacerbation of inflammation within chronic periapical lesions

Interleukin (IL)-17 plays an important role in inflammation and certain autoimmune diseases. However, its role in the pathogenesis of chronic dental periapical lesions has not been studied. Periapical lesion mononuclear cells (PL-MNC) were isolated from inflammatory cells and phenotypically analyzed by immunocytochemistry. The cells were cultured in vitro and IL-17 and IL-8 were measured in the culture supernatants. Controls were peripheral blood (PB) MNC. The level of IL-17 and the proportion of neutrophils were significantly higher in symptomatic lesions. In addition, the production of IL-17 was higher in culture supernatants of PL-MNC isolated from lesions with a predominance of T cells, and the IL-17 concentration correlated with the proportion of CD3+ and CD4+ cells. There was a positive correlation between the levels of IL-17 and IL-8 in the group of symptomatic lesions. The relationship between these cytokines was additionally confirmed on the basis of augmented production of IL-8 by both PL-MNC and PB-MNC treated with IL-17. Our results suggest that IL-17, by stimulating the production of IL-8, may play a role in exacerbating inflammation within chronic periapical lesions.

[Nasopalatine duct cyst]

BACKGROUND

Nasopalatine duct cyst is a developmental, nonodontogenic cyst of jaw.

CASE REPORT

We presented a 46-year-old male with nasopalatine duct cyst. The clinical examination revealed fluctuant swellings of the anterior palate, without pain, 4-5 cm in diametar. Both radiographs showed the presence of an ovoid radiolucency located in the midline of the maxilla between the roots of central maxillary incisor teeth with peripheral sclerosis, 25 x 35 cm in diametar. Surgical treatment was performed under local anaesthesia (Articainchloridum 4% - 3M ESPE) using a palatine approach. Postoperatively, no paresthesia of the anterior palate in inervation area of nasopalatine nerve was registrated. Pathohistologic findings proved both clinical and radiological diagnosis.

CONCLUSION

Nasopalatine duct cyst is a rare lesion which slowly develops. The diagnosis is mainly based on radiography, tooth vitality testing and histologic findings. After a correctly applied clinical diagnosis procedure and surgicel treatment, recurrence is rare.

Characterization of antigen-presenting cells in human apical periodontitis lesions by flow cytometry and immunocytochemistry

AIM

To analyse phenotypic characteristics of antigen-presenting cells (APC), isolated from human periapical lesions by flow cytometry and immunocytochemistry.

METHODOLOGY

Sixteen periapical lesions were digested for 15 min with 0.05% collagenase. Mononuclear cells, separated from other inflammatory cells by density centrifugation, were processed for flow cytometry and/or immunocytochemistry. Single and double immunostainings were performed using monoclonal antibodies specific for human CD45, CD3, CD19, CD14, HLA-DR, CD1a, CD83 and CD123.

RESULTS

Antigen-presenting cells (HLA-DR(+) cells) represented 32.9 +/- 17.8% of total mononuclear cells. Amongst them, B cells (HLA-DR(+) CD19(+)) were the predominant APC population, followed by activated macrophages (HLA-DR(+) CD14(+)), dendritic cells (DC) (HLA-DR(+) CD14(-) CD19(-) CD3(-)) and activated T cells (HLA-DR(+) CD3(+)). Based on the predominance of T cells (CD3(+)) or B cells and plasma cells (CD19(+) and CD19(lo), respectively) amongst mononuclear cell infiltrates, lesions were divided into T- and B-types. The percentage of DC in T-type lesions (27.1 +/- 6.8% of total HLA-DR(+) cells) was higher, compared with B-type lesions (10.3 +/- 5.2%) (P < 0.01). Within the DC population, the percentages of CD1a (Langerhans cell type) and CD123 (probably plasmacytoid DC type) did not differ significantly between the groups (P > 0.05). However, the percentage of mature DC (CD83(+)) was significantly higher in T-type periapical lesions (P < 0.05).

CONCLUSIONS

Flow cytometry and immunocytochemistry are suitable methods for phenotypic analysis of APC after their isolation from human periapical lesions. APC, that were phenotypically heterogeneous, constituted a significant component of infiltrating cells. Lesions with the predominance of T cells were characterized by a higher proportion of mature DC (HLA-DR(+)CD83(+) cells) than lesions with predominance of B cells/plasma cells.