Damage-regulated autophagy modulator 1 in oral inflammation and infection.

OBJECTIVES: Damage-regulated autophagy modulator (DRAM) 1 is a p53 target gene with possible involvement in oral inflammation and infection. This study sought to examine the presence and regulation of DRAM1 in periodontal diseases. MATERIAL AND METHODS: In vitro, human periodontal ligament fibroblasts were exposed to interleukin (IL)-1ß and Fusobacterium nucleatum for up to 2 days. The DRAM1 synthesis and its regulation were analyzed by real-time PCR, immunocytochemistry, and ELISA. Expressions of other autophagy-associated genes were also studied by real-time PCR. In vivo, synthesis of DRAM1 in gingival biopsies from rats and patients with and without periodontal disease was examined by real-time PCR and immunohistochemistry. For statistics, ANOVA and post-hoc tests were applied (p < 0.05). RESULTS: In vitro, DRAM1 was significantly upregulated by IL-1ß and F. nucleatum over 2 days and a wide range of concentrations. Additionally, increased DRAM1 protein levels in response to both stimulants were observed. Autophagy-associated genes ATG3, BAK1, HDAC6, and IRGM were also upregulated under inflammatory or infectious conditions. In vivo, the DRAM1 gene expression was significantly enhanced in rat gingival biopsies with induced periodontitis as compared to control. Significantly increased DRAM1 levels were also detected in human gingival biopsies from sites of periodontitis as compared to healthy sites. CONCLUSION: Our data provide novel evidence that DRAM1 is increased under inflammatory and infectious conditions in periodontal cells and tissues, suggesting a pivotal role of DRAM1 in oral inflammation and infection. CLINICAL RELEVANCE: DRAM1 might be a promising target in future diagnostic and treatment strategies for periodontitis.

A biphasic calcium phosphate coating for potential drug delivery affects early osseointegration of titanium implants.

BACKGROUND: Calcium phosphate (CaP) surface coatings may accelerate osseointegration and serve as a drug delivery system for mineral-binding biomolecules. In a pilot study, the impact of a commercially available, thin CaP coating on early osseous bone remodeling was compared with a modern, subtractive-treated rough surface (SLA-like) in an animal trial. METHODS: In 16 rabbits, 32 endosseous implants (CaP; n = 16, SLA-like; n = 16) were bilaterally inserted in the proximal tibia after randomization. After 2 and 4 weeks, bone-implant contact (BIC;%) in the cortical (cBIC) and the trabecular bone (sBIC) as well as volume of bone within the screw thread with the highest amount of new-formed bone (area;%) were analyzed. RESULTS: After 2 weeks, cBIC was significantly higher for CaP when compared with SLA-like (58 ± 7% versus 40.4 ± 18%; P = 0.021). sBIC for CaP was 14.7 ± 8% and for SLA-like 7.2 ± 7.8% (P = 0.081). For area, the mean volumes were 82.8 ± 10.8% for CaP and 73.6 ± 22% for SLA-like (P = 0.311). After 4 weeks, cBIC was 42.9 ± 13% for the CaP and 46.5 ± 29.1% for the SLA-like group (P = 0.775). An sBIC of 6.9 ± 9.3% was calculated for CaP and of 12.3 ± 4.8% for SLA-like (P = 0.202). The values for area were 62.3 ± 24.1% for CaP and 50.1 ± 25.9% for SLA-like (P = 0.379). CONCLUSIONS: The CaP coating has putative additional advantages in the early osseoconduction phases. It seems suitable for a feasible and clinical applicable bioactivation.

Role of Cathepsin S in Periodontal Inflammation and Infection.

Cathepsin S is a cysteine protease and regulator of autophagy with possible involvement in periodontitis. The objective of this study was to investigate whether cathepsin S is involved in the pathogenesis of periodontal diseases. Human periodontal fibroblasts were cultured under inflammatory and infectious conditions elicited by interleukin-1ß and Fusobacterium nucleatum, respectively. An array-based approach was used to analyze differential expression of autophagy-associated genes. Cathepsin S was upregulated most strongly and thus further studied in vitro at gene and protein levels. In vivo, gingival tissue biopsies from rats with ligature-induced periodontitis and from periodontitis patients were also analyzed at transcriptional and protein levels. Multiple gene expression changes due to interleukin-1ß and F. nucleatum were observed in vitro. Both stimulants caused a significant cathepsin S upregulation. A significantly elevated cathepsin S expression in gingival biopsies from rats with experimental periodontitis was found in vivo, as compared to that from control. Gingival biopsies from periodontitis patients showed a significantly higher cathepsin S expression than those from healthy gingiva. Our findings provide original evidence that cathepsin S is increased in periodontal cells and tissues under inflammatory and infectious conditions, suggesting a critical role of this autophagy-associated molecule in the pathogenesis of periodontitis.

Regulation of the autophagy-marker Sequestosome 1 in periodontal cells and tissues by biomechanical loading.

PURPOSE: Orthodontic treatment is based on the principle of force application to teeth and subsequently to the surrounding tissues and periodontal cells. Sequestosome 1 (SQSTM1) is a well-known marker for autophagy, which is an important cellular mechanism of adaptation to stress. The aim of this study was to analyze whether biomechanical loading conditions regulate SQSTM1 in periodontal cells and tissues, thereby providing further information on the role of autophagy in orthodontic tooth movement. METHODS: Periodontal ligament (PDL) fibroblasts were exposed to cyclic tensile strain of low magnitude (3%, CTSL), and the regulation of autophagy-associated targets was determined with an array-based approach. SQSTM1 was selected for further biomechanical loading experiments with dynamic and static tensile strain and assessed via real-time polymerase chain reaction (RT-PCR) and immunoblotting. Signaling pathways involved in SQSTM1 activation were analyzed by using specific inhibitors, including an autophagy inhibitor. Finally, SQSTM1 expression was analyzed in gingival biopsies and histological sections of rats in presence and absence of orthodontic forces. RESULTS: Multiple autophagy-associated targets were regulated by CTSL in PDL fibroblasts. All biomechanical loading conditions tested increased the SQSTM1 expression significantly. Stimulatory effects of CTSL on SQSTM1 expression were diminished by inhibition of the c­Jun N­terminal kinase (JNK) pathway and of autophagy. Increased SQSTM1 levels after CTSL were confirmed by immunoblotting. Orthodontic force application also led to significantly elevated SQTSM1 levels in the gingiva and PDL of treated animals as compared to control. CONCLUSIONS: Our in vitro and in vivo findings provide evidence of a role of SQSTM1 and thereby autophagy in orthodontic tooth movement.

Bilaminate synthetic dressing for partial thickness burns. Lack of cost reduction for inpatient care.

Forty-nine cases of second degree burns initially treated as inpatients from April 1984 through December 1987 are reviewed. Thirty-four patients were treated with bilaminate synthetic dressing (Biobrane) application, while 15 were treated with a topical antimicrobial, usually silver sulfadiazine. The burns ranged from 1 to 25 per cent total body surface area and were comparable in both groups. The mean age in each group was 30 years. Thirty patients were successfully treated with Biobrane, and their average hospital stay was 9.1 +/- 5.4 days compared with 9.2 +/- 8.6 days for the topically treated group. The mean hospital cost for dressings and supplies for the Biobrane group was $360 +/- $90 compared with $310 +/- $190 for the topical group. Four patients (12%) required Biobrane removal during their hospitalization, one due to increasing burn depth and three due to purulent fluid collections beneath the Biobrane. These burns were subsequently treated with topical antimicrobial agents and healed primarily. The mean total hospital stay for this group was 18.0 +/- 11.9 days with the costs being much higher secondary to the initial cost of the Biobrane, the costs associated with topical antibiotic therapy, and extended hospital stay. Although there was a decrease in nursing time and a subjective decrease in patient discomfort associated with using synthetic dressing, no benefit was found in either decreasing hospital stay or total cost of hospitalization and supplies used for inpatients treated at this institution.