Ahmed Y. Gamal

Periodontal ligament fibroblasts sustain destructive immune modulators of chronic periodontitis.

BACKGROUND In healthy periodontal tissue, innate immune responses effectively confine and suppress a bacterial insult. However, a disruption of the host-bacterial equilibrium may produce an overexpression of cytokines and lead to permanent, host-mediated tissue damage. Although such periodontal destruction primarily results from activated immune mechanisms, the site-specific damage suggests that local tissues participate in these pathologic changes. Periodontal ligament fibroblasts (PDLFs) are prominent in the periodontium and are critical in homeostasis and regeneration because they have the ability to produce multiple cytokines in response to a bacterial insult. These cells could play a role in the local pathogenesis of periodontal disease. METHODS We studied alkaline phosphatase (ALP) activity, interleukin (IL)-6 production, and morphologic characteristics of cultured PDLFs that were isolated from periodontally healthy sites (H-PDLFs) and diseased sites (D-PDLFs) in humans. Quantitative analyses of 84 genes that are related to inflammation were performed using real-time polymerase chain reaction arrays. RESULTS A mineralizing medium induced a significant increase of ALP in H-PDLFs, but no significant enzymatic changes were detected in D-PDLFs after such treatment. The protein and gene expression of IL6 showed a significant upregulation in D-PDLFs, which also demonstrated a significant upregulation of 54% of genes in the inflammatory gene arrays. CONCLUSIONS To our knowledge, these results represent the first biologic evidence that D-PDLFs retain uniquely inflammatory phenotypes that could maintain localized destructive signals in periodontitis. The overexpression of proinflammatory cytokines by PDLFs could amplify local inflammation by the continuous triggering of immune responses. In addition, the location of these cells could be critical in the progression of the inflammatory front into the deeper tissues.

Blood dendritic cells: “canary in the coal mine” to predict chronic inflammatory disease?

The majority of risk factors for chronic inflammatory diseases are unknown. This makes personalized medicine for assessment, prognosis, and choice of therapy very difficult. It is becoming increasingly clear, however, that low-grade subclinical infections may be an underlying cause of many chronic inflammatory diseases and thus may contribute to secondary outcomes (e.g., cancer). Many diseases are now categorized as inflammatory-mediated diseases that stem from a dysregulation in host immunity. There is a growing need to study the links between low-grade infections, the immune responses they elicit, and how this impacts overall health. One such link explored in detail here is the extreme sensitivity of myeloid dendritic cells (mDCs) in peripheral blood to chronic low-grade infections and the role that these mDCs play in arbitrating the resulting immune responses. We find that emerging evidence supports a role for pathogen-induced mDCs in chronic inflammation leading to increased risk of secondary clinical disease. The mDCs that are elevated in the blood as a result of low-grade bacteremia often do not trigger a productive immune response, but can disseminate the pathogen throughout the host. This aberrant trafficking of mDCs can accelerate systemic inflammatory disease progression. Conversely, restoration of dendritic cell homeostasis may aid in pathogen elimination and minimize dissemination. Thus it would seem prudent when assessing chronic inflammatory disease risk to consider blood mDC numbers, and the microbial content (microbiome) and activation state of these mDCs. These may provide important clues (“the canary in the coal mine”) of high inflammatory disease risk. This will facilitate development of novel immunotherapies to eliminate such smoldering infections in atherosclerosis, cancer, rheumatoid arthritis, and pre-eclampsia.

Enhancing Guided Tissue Regeneration of Periodontal Defects by Using a Novel Perforated Barrier Membrane

BACKGROUND The present study was designed to determine whether exclusion of the gingival connective tissue (CT) and periosteum with contained stem cells has a positive or negative effect on periodontal regeneration by comparing the use of a novel modified perforated collagen membrane with a traditional cell occlusive barrier membrane. METHODS Twenty non-smoking patients with severe chronic periodontitis were included in the study. Single deep intrabony defects from each of the patients were randomly divided into two groups, as follows: occlusive bovine collagen membranes (OM control group, 10 sites) and modified perforated bovine collagen membranes (MPM test group, 10 sites). Plaque index, gingival index, probing depth (PD), clinical attachment level (CAL), defect base level (DBL), and crestal bone level (CBL) were measured at baseline and were reassessed at 6 and 9 months after therapy to evaluate the quantitative changes in the defect. RESULTS At 6- and 9-month observation periods, the MPM-treated sites showed a statistically significant improvement in PD reduction and CAL gain compared with the OM control group. DBL was significantly reduced with no significant difference between the two groups at 6- and 9-month observation periods. CBL was significantly higher in the MPM group when compared with that of the OM group at both observation periods. The postoperative differences between the two groups were 2 and 1.7 mm at 6 and 9 months, respectively, in favor of the MPM-treated sites. CONCLUSIONS The present study demonstrated enhanced clinical outcomes when using novel MPMs compared to OMs in guided tissue regeneration procedures. These results may be affected by the penetration of gingival CT contained stem cells and periosteal cells and their differentiation into components of the attachment apparatus.

Enhanced β-Tricalcium Phosphate Blended Clot Adhesion to EDTA Biomodulated Periodontally Affected Root Surfaces: In Vivo Scanning Electron Microscopy Evaluation

BACKGROUND The objective of this study is to evaluate β-tricalcium phosphate (β-TCP) blended clot adhesion to EDTA-conditioned root surfaces. METHODS Sixty patients with chronic periodontitis and two teeth designated for extraction were enrolled in this study. Patients were divided into six groups (G1 to G6; 10 patients in each). In G1, intrabony defects were grafted with β-TCP with a particle size ranging from 150 to 500 μm. In G2, intrabony defects were grafted with β-TCP with a particle size ranging from 63 to 150 μm. Roots in G3 were etched for 2 minutes with a neutral EDTA, followed by defect overfill of the β-TCP used for G1. Defects of G4 were treated by the same method as in G3, except the EDTA gel application was 4 minutes. Roots in G5 and G6 were etched for 2 and 4 minutes, respectively, followed by the defect fill with β-TCP used for G2. For each patient, one tooth was extracted immediately after surgery and the other tooth was extracted at 14 days for scanning electron microscopy evaluation. RESULTS Fourteen days after surgery, the G1 and G2 samples revealed undetected graft particles. The G3 samples showed areas of adherent β-TCP particles covering about 42.5%. The G4 samples showed 53.7% graft material coverage. The G5 and G6 samples had adherent grafted particles that covered 77.9% and 82.7%, respectively. CONCLUSION Root conditioning with EDTA gel improves β-TCP blended clot adhesion to periodontally involved root surfaces.

Crevicular Fluid Growth Factors Release Profile Following the Use of Platelet-Rich Fibrin and Plasma Rich Growth Factors in Treating Periodontal Intrabony Defects: A Randomized Clinical Trial

BACKGROUND The open, usually contaminated nature of periodontal defects could negatively affect availability and activity of platelet concentrate-suggested growth factors (GF). The aim of this study is to test this hypothesis and investigate concentrations of: 1) vascular endothelial growth factor (VEGF) and 2) platelet-derived growth factor (PDGF-BB) in gingival crevicular fluid (GCF) from localized intrabony defects treated with platelets rich in growth factors (PRGF) or platelet-rich fibrin (PRF) compared with a control xenograft defect filling. METHODS Thirty non-smoking patients suffering severe chronic periodontitis were allocated to this randomized, prospective, single-masked trial. Each patient had one interproximal defect randomly distributed to: 1) group 1: bone-substitute grafting control (n = 10); 2) group 2: experimental PRGF (n = 10); or 3) group 3: PRF (n = 10). Clinical parameters were measured at baseline and 6 and 9 months following therapy. GCF samples were obtained on days 1, 3, 7, 14, 21, and 30 after therapy for evaluation of VEGF and PDGF-BB levels. RESULTS On days 1, 3, and 7 following surgery, mean levels of VEGF and PDGF-BB at sites treated with PRGF and PRF were not significantly different versus the control. Levels of PDGF-BB and VEGF were higher in the PRGF-treated group, but differences were not significant. Growth factor levels decreased significantly in samples collected on days 14, 21, and 30 with non-significant differences among the three groups. No significant clinical differences were reported among the three groups during the two observation periods (early period: days 1, 3, and 7; and later period: days 14, 21, and 30). CONCLUSIONS Within the limits of the present study, it can be concluded that PRF and PRGF platelet concentrate failed to augment clinical effects achieved with the xenograft alone in treating intrabony defects. Periodontal defects could not retain extraphysiologic levels of GF suggested to be associated with platelet concentrate.

Versatility of tubularized incised plate urethroplasty in the management of different types of hypospadias: 5-year experience

BACKGROUND The outcomes of urethroplasty in the management of different types of hypospadias have continued to improve since the introduction of the tubularized incised plate (TIP) urethroplasty (Snodgrass method). The aim of this study was to evaluate the feasibility and applicability of TIP urethroplasty in the management of different types of hypospadias. MATERIALS AND METHODS This work was carried out at Al-Azhar University Hospital, Cairo, Egypt in the period from January 2002 to December 2002 and King Abdul Aziz Specialist Hospital, Taif, Saudi Arabia; in the period from January 2003 to January 2007 by the same authors. The medical records of 175 boys with different types of hypospadias, who underwent TIP urethroplasty, were critically reviewed. Their age ranged from 9 to 36 months (mean age; 22.72 +/- 7.75 months).The period of follow-up was ranged from 7 to 60 months (mean 34.42 +/- 15.41). RESULTS All families were happy with penile aesthetic appearance. The total number of boys with different types of hypospadias was 175 (145 1ry and 30 2ry). Out of 175 cases, the overall urethrocutaneous fistula rate was 11 (6.29%), and the overall rates for glanular dehiscence, urethral stricture, meatal stenosis and meatal regression were 4 (2.29%), 5 (2.86%), 17 (9.71%), and 10 (5.71%), respectively. All cases of urethral stricture and most cases of meatal stenosis 12 (6.86%) responded well to regular urethral dilatation. Meatoplasty was performed in only 5 (2.85%) cases (1 of 1ry and 4 of 2ry cases). Secondary surgery for fistula repair and glans closure was successful in all patients. All children void with a single straight urinary stream in a forward direction, and have a rounded glans with vertical slit- like terminal glanular meatus. The mean hospital stay was 4.6 days. CONCLUSION TIP urethroplasty with neourethral coverage using a vascularized pedicle of dartos flap is versatile and simple operation in management of different types of hypospadias. It has a good functional and cosmetic outcome.

Platelet-Derived Growth Factor-BB Release Profile in Gingival Crevicular Fluid After Use of Marginal Periosteal Pedicle Graft as an Autogenous Guided Tissue Membrane to Treat Localized Intrabony Defects

BACKGROUND The aim of this study is to evaluate levels of platelet-derived growth factor-BB (PDGF-BB) in gingival crevicular fluid (GCF) during the early stages of healing for sites treated by marginal periosteal pedicle (MPP) graft as an autogenous guided tissue membrane compared to that of the control open flap debridement (OFD). METHODS Fifteen non-smoking patients (13 males and 2 females) with severe chronic periodontitis participated in this prospective, controlled, masked trial. Each subject contributed matched pairs of 2- or 3-walled intrabony interproximal defects in premolar or molar teeth. Interproximal contralateral defects were randomly assigned to either the MPP group 1 or control OFD group 2. GCF samples were collected at 1, 3, 7, 14, and 30 days after surgery. PDGF-BB in the GCF samples was measured using a human PDGF-BB enzyme-linked immunosorbent assay kit. RESULTS In both MPP and OFD, PDGF-BB concentrations peaked in the samples obtained during the early postoperative days (days 2 and 3) and decreased sharply in the samples obtained 7, 14, and 30 days post-surgery. CONCLUSION Periosteal coverage of periodontal defects is not associated with a significant increase in PDGF-BB levels.

Platelet-derived growth factor BB treated osteoprogenitors inhibit bone regeneration.

The study evaluates the ability of osteoprogenitors treated with platelet-derived growth factor BB (PDGF-BB) delivered on vinyl styrene microbeads (VSM) to regenerate rat calvarial critical-size defects (CSDs). Fetal rat calvarial cells were cultured and tested for their ability to attach to VSM using scanning electron microscopy. Twenty-five rats were equally divided into 5 groups; a negative control (GPI), vinyl styrene microbeads (GPII), PDGF-BB (GPIII), VSM plus osteoblastic progenitors (GPIV), and VSM plus PDGF-BB treated osteoblastic progenitors (GPV). CSDs were created and reconstructed according to the mentioned study design. After 16 weeks, animals were sacrificed and defect areas evaluated for bone regeneration. Cells attached to the microbeads; however, their morphology and topography were affected by the PDGF-BB. Transplanting the VSM/cells constructs to CSDs revealed significant reduction of bone regeneration upon pretreatment of the cells with PDGF-BB. However, short-term application of PDGF-BB to CSD stimulated bone regeneration. The ability of osteoprogenitor cells to regenerate bone was significantly reduced upon pretreatment with PDGF-BB in vitro. However, adding PDGF-BB at the time of surgery had stimulated bone regeneration.

Gingival crevicular fluid vascular endothelial cell growth factor and platelet-derived growth factor-BB release profile following the use of perforated barrier membranes during treatment of intrabony defects: a randomized clinical trial

BACKGROUND AND OBJECTIVE Perforated barrier membranes open channels between the suprabony and intrabony compartments of the defect, which could allow for more physiologic cellular interactions between different components of the periodontium during guided tissue regeneration surgery. To test this assumption, this study was designed to evaluate levels of vascular endothelial cell growth factor (VEGF) and platelet-derived growth factor (PDGF)-BB in gingival crevicular fluid during the early stages of healing of localized intrabony defects treated with perforated membranes (PMs) or non-PMs, as compared with open flap debridement. MATERIAL AND METHODS Thirty non-smoking patients with severe chronic periodontitis participated in this prospective, randomized and single blinded trial. Each patient contributed one interproximal defect that was randomly assigned to the PM group (n = 10), occlusive membrane (OM) group (n = 10) or open flap debridement (OFD) group (n = 10). Plaque index, gingival index, probing depth, clinical attachment level and the intrabony depth of the defect were measured at baseline and reassessed at 6 and 9 mo after therapy. Gingival crevicular fluid samples were collected on days 1, 3, 7, 14, 21 and 30 d after therapy for the changes in VEGF and PDGF-BB levels. RESULTS During the early stages of healing (1, 3 and 7 d), the mean VEGF and PDGF-BB concentrations at sites treated with PMs and OFD peaked with a statistically significant difference as compared with the OM-treated group. VEGF and PDGF-BB levels at sites treated with PMs and OFD were not statistically different. Growth factor levels decreased sharply in the samples obtained at days 21 and 30 with non-significant differences between the three groups. Nine months after therapy, the PM-treated group showed a statistically significant improvement in probing depth, clinical attachment level and intrabony defect compared to the OM and OFD groups. CONCLUSIONS Within the limits of the present study, one can conclude that PM coverage of periodontal defects is associated with initial gingival crevicular fluid growth factor upregulation that could improve the clinical outcomes of guided tissue regeneration surgery.

Chlorhexidine Controlled-Release Profile After EDTA Root Surface Etching: An In Vivo Study

BACKGROUND The main objective of the present study was to quantify chlorhexidine (CHX) release after the use of CHX-EDTA root surface treatment as a local-delivery antimicrobial vehicle. METHODS Twenty non-smoking patients clinically diagnosed as having moderate-to-severe chronic periodontitis were selected to participate in this study. After cause-related therapy, one site in every patient received defect overfill with CHX gel 2% (20 sites). In addition, twenty contralateral sites received defect fill of CHX gel after 3 minutes of 24% EDTA gel root surface etching (20 sites). Gingival crevicular fluid samples were collected at 1, 3, 7, and 14 days post-therapy. RESULTS The CHX-EDTA group showed statistically significantly higher levels of CHX than those of the control group at 1, 3, and 7 days. At 14 days, the CHX-EDTA group showed 0.8 mg/mL values. CONCLUSION The use of CHX-EDTA root surface treatment as a local-delivery antimicrobial improves CHX substantivity.