Correction to: Expanding the phenotype of hypomaturation amelogenesis imperfecta due to a novel SLC24A4 variant.

In the pedigree, one of the individuals was marked as unaffected whereas it is heterozygous for the SLC24A4 mutation.

Expanding the phenotype of hypomaturation amelogenesis imperfecta due to a novel SLC24A4 variant.

OBJECTIVES: Biallelic variants in solute carrier family 24 member 4 (SLC24A4) have been previously reported to cause non-syndromic autosomal recessive amelogenesis imperfecta (AI) of the pigmented hypomaturation type (MIM #615887). We here describe a novel variant in SLC24A4 causing mild enamel hypomaturation defects also in heterozygous individuals. MATERIALS AND METHODS: In the present pedigree analysis, a large consanguineous Syrian family with AI of the hypomaturation type was investigated by clinical and dental evaluation, and exome and Sanger sequencing. Dental histological investigations of seven primary and two permanent teeth were performed. RESULTS: Homozygous variants in SLC24A4 (c.1604G>A; p.Gly535Asp) were identified in five individuals with brown discolorations and irregular pits and grooves of the teeth. Severe attritions, occlusal abfractions, and the radiological lack of contrast between enamel and dentin point out a mineralization defect. Histological dental investigations confirmed the clinical diagnosis of AI of the hypomaturation type. In two heterozygous individuals, a mild hypomaturation defect was present with white and light brown enamel discolorations. CONCLUSIONS: This is the first report of heterozygous SLC24A4 variants causing mild hypomaturation defects, providing confirmatory evidence that the function of SLC24A4 in calcium transport has a crucial role in the maturation stage of amelogenesis. CLINICAL RELEVANCE: The present report is expanding the clinical phenotype of SLC24A4 variants to more severe forms of amelogenesis imperfecta. An autosomal-dominant inheritance pattern with mild clinical phenotypes in heterozygotes has to be considered.

Hard Tissue Augmentation of Aged Bone by Means of a Tin-Free PLLA-PCL Co-Polymer Exhibiting in vivo Anergy and Long-Term Structural Stability.

BACKGROUND: Due to aging, tissue regeneration gradually declines. Contemporary strategies to promote tissue-specific regeneration, in particular in elderly patients, often include synthetic material apt for implantation primarily aiming at upholding body functions and regaining appropriate anatomical and functional integrity. OBJECTIVE: Biomaterials suitable for complex reconstruction surgical procedures have to exert high physicochemical stability and biocompatibility. METHOD: A polymer made of poly-L-lactic acid and poly-ε-caprolactone was synthesized by means of a novel tin-free catalytic process. The material was tested in a bioreactor-assisted perfusion culture and implanted in a sheep model for lateral augmentation of the mandible. Histological and volumetric evaluation was performed 3 and 6 months post-implantation. RESULTS: After synthesis the material could be further refined by cryogrinding and sintering, thus yielding differently porous scaffolds that exhibited a firm and stable appearance. In perfusion culture, no disintegration was observed for extended periods of up to 7 weeks, while mesenchymal stromal cells readily attached to the material, steadily proliferated, and deposited extracellular calcium. The material was tested in vivo together with autologous bone marrow-derived stromal cells. Up to 6 months post-implantation, the material hardly changed in shape with composition also refraining from foreign body reactions. CONCLUSION: Given the long-term shape stability in vivo, featuring imperceptible degradation and little scarring as well as exerting good compatibility to cells and surrounding tissues, this novel biomaterial is suitable as a space filler in large anatomical defects.

Pervasion of beta-tricalcium phosphate with nanodiamond particles yields efficient and safe bone replacement material amenable for biofunctionalization and application in large-size osseous defect healing.

Biofunctionalization of scaffold materials can enable the healing of large bone defects. In case of minimally invasive guided-bone regeneration (GBR), limitations are however hard-to-control side effects related to the potential release of biofactors into the systemic environment. Biofactors can be stably bound to nanodiamond particles (ND) through physisorption. We therefore tested the biological and clinical effects of refining beta-tricalcium phosphate (ßTCP) with ND in vitro and in vivo. In vitro, ßTCP carrying 4% ND resulted in enhanced attachment of mesenchymal stem cells. When assessing GBR after lateral augmentation of the mandible in sheep showed that ND in ßTCP resulted in a consistently steady bone formation when compared to pure ßTCP, demonstrating the biological inert behavior and the potential clinical safety of ND.

Long-lived murine osteocytes are embodied by craniofacial skeleton in young and old animals whereas they decrease in number in postcranial skeletons at older ages.

BACKGROUND: Osteocytes are engaged in life-enduring processes such as bone remodelling, fracture healing or osseointegration of implants. Over age, ossification processes and regenerative capacity can greatly differ in mandible and femur. OBJECTIVE: Mesenchymal stem cells from cranial and postcranial bones are of different embryologic origin. This may be the reason why the regenerative capacity differs between cranial and postcranial bones in old patients. It was hypothesised that different ageing patterns, reflected by osteocyte density, lacunar density and osteoid formation, exist between murine mandibles and femurs. MATERIAL AND METHODS: Mandible and femur of young (4 months) and old (34-36 months old) male C57Bl/6 mice were histologically investigated to determine the number of lacunae occupied with osteocytes. Osteoid formation was revealed by Masson-Goldner staining, and the spatial distribution of BMP-2 synthesis was examined. RESULTS: Over lifetime, the number of lacunae occupied with osteocytes only showed a modest decrease in mandibular bone (old 85.63%/young 91.12%) while greatly diverging in the femur (old 55.99%/young 93.28%). In equal measure, old femur exhibited less osteoid formation and decreased BMP-2 expression. CONCLUSION: Tissue-specific conduct of bone ageing is moulded by osteocytic activities, which was found to vary between postcranial and craniofacial skeleton. The latter harbours long-lived osteocytes also in old animals which assures lifelong bone integrity. Preliminary concurring findings from a human cadaver, also presented in this contribution, provided a rationale for recommending the translatability to humans.

How meta-analytic evidence impacts clinical decision making in oral implantology: a Delphi opinion poll.

OBJECTIVES: To investigate the impact of meta-analytic evidence in scientific literature on clinical decision making in the field of oral implantology. METHODS: A Delphi opinion poll was performed at the meeting of the "Next Generation" Committees of the Austrian, German and Swiss Societies for Implantology (ÖGI, DGI and SGI). First, the experts gave their opinion on 20 questions regarding routine implant treatment (uninformed decisions), then they were confronted with up-to-date Level I evidence from scientific literature on these topics and again asked to give their opinion (informed decisions) as well as to rate the available evidence as satisfactory or insufficient. Topics involved surgical issues, such as immediate implant placement, flapless surgery, tilted and short implants and bone substitute materials, as well as opinions on prosthodontic paradigms, such as immediate loading, abutment materials and platform switching. RESULTS: Compared to their uninformed decisions prior to confrontation with recent scientific literature, on average, 37% of experts (range: 15-50%) changed their opinion on the topic. When originally favoring one treatment alternative, less than half were still convinced after review of meta-analytic evidence. Discrepancy between uninformed and informed decisions was significantly associated with insufficient evidence (P = 0.014, 49% change of opinion vs. 26% on topics rated as sufficiently backed with evidence). Agreement regarding strength of evidence could be reached for eight topics (40%), in three issues toward sufficiency and in five issues toward lack of evidence. CONCLUSION: Confrontation with literature results significantly changes clinical decisions of implantologists, particularly in cases of ambiguous or lacking meta-analytic evidence.

Biofunctionalization of scaffold material with nano-scaled diamond particles physisorbed with angiogenic factors enhances vessel growth after implantation.

Biofunctionalized scaffold facilitates complete healing of large defects. Biological constraints are induction and ingrowth of vessels. Angiogenic growth factors such as vascular endothelial growth factor or angiopoietin-1 can be bound to nano-scaled diamond particles. Corresponding bioactivities need to be examined after biofunctionalization. We therefore determined the physisorptive capacity of distinctly manufactured, differently sized nDP and the corresponding activities of bound factors. The properties of biofunctionalized nDPs were investigated on cultivated human mesenchymal stem cells and on the developing chicken embryo chorio-allantoic membrane. Eventually porous bone substitution material was coated with nDP to generate an interface that allows biofactor physisorption. Angiopoietin-1 was applied shortly before scaffold implantation into an osseous defect in sheep calvaria. Biofunctionalized scaffolds exhibited significantly increased rates of angiogenesis already one month after implantation. Conclusively, nDP can be used to ease functionalization of synthetic biomaterials. FROM THE CLINICAL EDITOR: With the advances in nanotechnology, many nano-sized materials have been used in the biomedical field. This is also true for nano-diamond particles (nDP). In this article, the authors investigated the physical properties of functionalized nano-diamond particles in both in-vitro and in-vivo settings. The positive findings would help improve understanding of these nanomaterials in regenerative medicine.

Condylar Erosion in Patients With Chronic Temporomandibular Joint Arthralgia: A Cone-Beam Computed Tomography Study.

PURPOSE: The objective of this study was to assess the association between temporomandibular joint (TMJ) condylar erosion and chronic TMJ arthralgia. MATERIALS AND METHODS: Based on a sample size estimation, this case-and-control study involved 198 patients 16 to 73 years old recruited from a routine clinical practice (99 cases, patients with chronic TMJ arthralgia and mean pain duration of 16.4 months; 99 controls, asymptomatic patients without a history of orofacial pain). The clinical diagnosis of arthralgia was made according to the Research Diagnostic Criteria for Temporomandibular Disorders. Cone-beam computed tomographic (CBCT) images were evaluated for the presence or absence of erosive osseous changes of the TMJ condyle. Severity of TMJ condylar erosion was classified as grade 0 (absence of erosion), grade I (slight erosion), grade II (moderate erosion), or grade III (extensive erosion). Logistic regression analysis was used to assess the association between chronic TMJ arthralgia and condylar erosion, adjusting for age, gender, number of missing posterior teeth, and number of dental quadrants with missing posterior teeth. RESULTS: TMJ condylar erosion was found in 59.6% of cases and 21.2% of controls. There was a significant association between TMJ arthralgia and degree of condylar erosion (P < .001). The odds ratio that a TMJ with condylar erosion grade II might belong to the TMJ arthralgia group was strong (3.1:1; 95% confidence interval [CI], 1.17 to 8.09) and significant (P = .023). Significant increases in risk of TMJ arthralgia occurred with condylar erosion grade III (7.7:1; 95% CI, 3.09 to 19.18; P < .001). CONCLUSIONS: The study provides evidence of an association between TMJ condylar erosion and chronic TMJ arthralgia.

Systematic review of craniofacial osteosarcoma regarding different clinical, therapeutic and prognostic parameters.

Background: Osteosarcomas are the most common primary bone tumor while occurrence in the craniofacial skeleton is relatively rare. There are clinical differences of osteosarcomas regarding their location. In this regard craniofacial osteosarcomas (COS) have special characteristics. Extracranial osteosarcomas (EOS) occur mainly in the long bones of the extremities (tibia, humerus and femur). These tumors metastasize hematogenically at a very early stage. In comparison, COS are mainly localized in the mandible and maxilla, occur later in life and show significantly less and later metastasis and respond differently to adjuvant therapy. In the literature, clinical characteristics of COS and EOS are rarely compared directly. The aim of this systematic review is to answer the question whether COS and EOS exhibit fundamentally different clinical behavior and how they differ in terms of survival rates and response to different therapies. Methods: A systemic review was performed. Pubmed, Cochrane and Google Scholar were used as search engines. The literature research was done by using clearly defined terms and their links. 124 full texts were selected and evaluated for this review. The inclusion criteria were determined using the PICO model. Results: COS have significantly better survival rates, especially if they are located in the jawbone. Surgical R0 resection is crucial for therapeutic success. The study situation regarding the benefit of neoadjuvant chemotherapy in COS is very inhomogeneous. There is also no evidence for the benefit of adjuvant radio- or chemotherapy in COS. The large heterogeneity of the studies in terms of therapeutic concept, initial situation of the patients and outcome considered, as well as the small number of patients with craniofacial osteosarcoma were limiting factors. Conclusion: The results of this study show the clear therapeutic and prognostic differences between COS and EOS and underline the necessity to consider both types of osteosarcoma as independent tumor entities in future studies. Furthermore, the study highlights the importance of surgical R0 resection for the prognosis of COS patients. There is no evidence for therapeutic benefit of adjuvant/neoadjuvant radio-/chemotherapy in R0 resected COS cases.

Early responses to 3 mm resilient stabilization appliance therapy for sub-acute and chronic temporomandibular disorder pain predict 12-months follow-up outcomes.

Objective: To estimate whether outcomes at 12-month follow-up may be predicted by an intermediate and early response to a 3 mm resilient splint therapy for unilateral arthralgia and myofascial pain assessed at 3- and 6-month follow-ups.Methods: Data obtained from one retrospective cohort study consisting of 78 patients suffering from chronic and sub-acute unilateral arthralgia and myofascial pain who were managed with 3 mm resilient splint therapy were subjected to analysis.Results: Baseline visual analog scale (VAS) intensity, gender as well as changes in the intensity of VAS pain at 3- and 6-month follow-ups predicted unilateral arthralgia and myofascial pain group membership (p < .001). The function classified 83.3% of the cross-validated and 87.2% of original grouped cases correctly.Discussion: The proposed model may be used to timely identify patients who are at risk of developing prolonged non-responsive unilateral arthralgia and myofascial pain chronicity.

In vivo investigation on connective tissue healing to polished surfaces with different surface wettability.

OBJECTIVES: Connective tissue in contact to transgingival/-dermal implants presents itself as tight scar formation. Although rough surfaces support the attachment they increase bacterial colonisation as well. In contrast to surface roughness, little is known about the influence of surface wettability on soft-tissue healing in vivo. We therefore investigated the influence of different surface wettabilities on connective tissue healing at polished implant surfaces in vivo. MATERIAL AND METHODS: Three polished experimental groups (titanium, titanium coated with hydrophobic nano-crystalline diamond (H-NCD) and titanium coated with hydrophilic nano-crystalline diamond (O-NCD) were inserted into the subcutaneous connective tissue of the abdominal wall of 24 rats. Animals were sacrificed after 1 and 4 weeks resulting in eight specimen per group per time point. Specimen were subjected to histological evaluation (van Giesson's staining) and immunohistochemistry staining for proliferating cell nuclear antigen (PCNA), fibronectin and tumour necrosis factor-alpha (TNF-α). RESULTS: Histological evaluation revealed dense scar formation at the titanium and H-NCD surfaces. In contrast, the connective tissue was loose at the O-NCD surface with a significantly higher number of cells after 4 weeks. O-NCD demonstrated a strong expression of PCNA and fibronectin but a weak expression of TNF-α. In contrast, the PCNA and fibronectin expression was low at the titanium and H-NCD, with a strong signal of TNF-α at the H-NCD surface. CONCLUSIONS: Hydrophilicity influences the connective tissue healing at polished implant surfaces in vivo positively. The attachment of connective tissue and the number of cells in contact to the surface were increased. Moreover, the inflammatory response is decreased at the hydrophilic surface.

A Tool for Rapid Assessment of Functional Outcomes in Patients with Head and Neck Cancer.

Head and neck cancer (HNC) and its treatment can lead to various functional impairments. We developed and validated an instrument for rapid physician-rated assessment of basic functional outcomes in HNC patients. HNC-relevant functional domains were identified through a literature review and assigned to verbal ratings based on observable criteria. The instrument draft was subjected to systematic expert review to assess its face and content validity. Finally, the empirical validity, reliability, and responsiveness of the expert-adapted Functional Integrity in Head and Neck Cancer (HNC-FIT) scales were assessed in healthy controls and in HNC patients. A matrix of the 6 functional domains of oral food intake, respiration, speech, pain, mood, and neck and shoulder mobility was created, each with 5 verbal rating levels. Face and content validity levels of the HNC-FIT scales were judged to be adequate by 17 experts. In 37 control subjects, 24 patients with HNC before treatment, and in 60 HNC patients after treatment, the HNC-FIT ratings in the 3 groups behaved as expected and functional domains correlated closely with the outcome of corresponding scales of the EORTC-HN35-QoL questionnaire, indicating good construct and criterion validity. Interrater reliability (rICC) was ≥0.9 for all functional domains and retest reliability (rICC) was ≥0.93 for all domains except mood (rICC = 0.71). The treatment effect size (eta-square) as a measure of responsiveness was ≥0.15 (p < 0.01) for fall domains except for breathing and neck and shoulder mobility. The median HNC-FIT scale completion time was 1 min 17 s. The HNC-FIT scale is a rapid tool for physician-rated assessment of functional outcomes in HNC patients with good validity, reliability, and responsiveness.

Osteocyte numbers decrease only in postcranial but not in cranial bones in humans of advanced age.

BACKGROUND: Bone ageing is governed by the linked activities of short-lived osteoblasts and osteoclasts in conjunction with long-lived osteocytes present in osseous structure. Besides their maintenance function, osteogenic cells also gain specific positional information, which may potentially trigger ageing-associated cellular deviations in terminally differentiated osteocytes differently in cranial versus postcranial tissues. METHODS: We therefore investigated bone taken from deceased aged humans explanted at five distinct anatomical positions throughout the body and assessed physical and biological determinants applying radiologic and histologic measures. RESULTS: We were able to show that significantly more osteocytes reside in aged cortical bone at cranial positions than within axial or limb skeleton. These cellular states and conditions were not found in the corresponding trabecular bone, where osteocyte numbers remain also high at postcranial positions. Parallel comparative analyses of bone microstructure as analyzed by means of computer tomography showed no significant differences. CONCLUSIONS: Considering differences and commonalities regarding the bone samples, such as loading, mechanisms of ossification or the surrounding stromal cell compartment, our findings indicate that positional information laid down during ontogenetic processes is instructive during the entire life thus potentially also moulding spatial-specific mechanistic distinctions of bone ageing.

Impact of Nano-Crystalline Diamond Enhanced Hydrophilicity on Cell Proliferation on Machined and SLA Titanium Surfaces: An In-Vivo Study in Rodents.

By coating surfaces with nano-crystalline diamond (NCD) particles, hydrophilicity can be altered via sidechain modifications without affecting surface texture. The present study aimed to assess the impact of NCD hydrophilicity on machined and rough SLA titanium discs on soft tissue integration, using a rodent model simulating submerged healing. Four different titanium discs (machined titanium = M Titanium, NCD-coated hydrophilic machined titanium = M-O-NCD, sand blasted acid etched (SLA Titanium) titanium, and hydrophilic NCD-coated SLA titanium = SLA O-NCD) were inserted in subdermal pockets of 12 Wistar rats. After one and four weeks of healing, the animals were sacrificed. Biopsies were embedded in methyl methacrylate (MMA), and processed for histology. The number of cells located within a region of interest (ROI) of 10 µm around the discs were counted and compared statistically. Signs of inflammation were evaluated descriptively employing immunohistochemistry. At one week, M-O-NCD coated titanium discs showed significantly higher amounts of cells compared to M Titanium, SLA Titanium, and SLA-O-NCD (p < 0.001). At four weeks, significant higher cell counts were noted at SLA-O-NCD surfaces (p < 0.01). Immunohistochemistry revealed decreased inflammatory responses at hydrophilic surfaces. Within the limits of an animal study, M-O-NCD surfaces seem to stimulate cell proliferation in the initial healing phase, whereas SLA-O-NCD surfaces appeared advantageous afterwards.

Functionalization of bone implants with nanodiamond particles and angiopoietin-1 to improve vascularization and bone regeneration.

One of the major challenges in bone tissue engineering is adequate vascularization within bone substituents for nutrients and oxygen supply. In this study, the production and results of a new, highly functional bone construct consisting of a commercial three-dimensional ß-tricalcium phosphate scaffold (ß-TCP, ChronOS®) and hydrophilic, functionalized nanodiamond (ND) particles are reported. A 30-fold increase in the active surface area of the ChronOS + ND scaffold was achieved after modification with ND. In addition, immobilization of angiopoietin-1 (Ang-1) via physisorption within the ß-TCP + ND scaffold retained the bioactivity of the growth factor. Homogeneous distribution of the ND and Ang-1 within the core of the three-dimensional scaffold was confirmed using ND covalently labelled with Oregon Green. The biological responses of the ß-TCP + ND scaffold with and without Ang-1 were studied in a sheep calvaria critical size defect model showing that the ß-TCP + ND scaffold improved the blood vessel ingrowth and the ß-TCP + ND + ND + Ang-1 scaffold further promoted vascularization and new bone formation. The results demonstrate that the modification of scaffolds with tailored diamond nanoparticles is a valuable method for improving the characteristics of bone implants and enables new approaches in bone tissue engineering.

A domestic porcine model for studying the effects of radiation on head and neck cancers.

BACKGROUND: Radiation therapy (RT) of the head and neck region is often accompanied by serious side effects. Research in this area is needed to improve treatment outcomes and ameliorate therapy tolerance. Laboratory rodents are barely matching today's clinical standards in RT research. Yet domestic swine (Sus scrofa domestica) have previously proved suitable for various advanced tests in clinical research and training. We therefore investigated whether S. scrofa domestica is also appropriate for irradiation of the mandible. STUDY DESIGN: A common scheme for irradiation treatment of S. scrofa domestica mandibles in a split-mouth design was acquired by applying computed tomography (CT) scanning under sedation. Basing on close anatomic resemblance, a standard treatment plan comprising 2 opposed irradiation fields could be accomplished. RESULTS: RT was carried out in a clinical environment with 2 × 9 Gy. The resulting operating procedure facilitated complication-free sedation, transport, positioning, CT scanning, and effective irradiation. CONCLUSION: Based on common standards applied for RT in humans, domestic pigs can be employed to progress RT clinical research. Due to their human-like anatomy, physiology, size, and weight, the swine model is expedient for advancing experimental RT of the head and neck area.

Craniomaxillofacial trauma: synopsis of 14,654 cases with 35,129 injuries in 15 years.

Craniomaxillofacial (CMF) trauma occurs in isolation or in combination with other serious injuries, including intracranial, spinal, and upper- and lower-body injuries. It is a major cause of expensive treatment and rehabilitation requirements, temporary or lifelong morbidity, and loss of human productivity. The aim of this study was to evaluate patterns of CMF trauma in a large patient sample within a 15-year time frame. Between 1991 and 2005, CMF trauma data were collected from 14,654 patients with 35,129 injuries at the Department of Cranio-Maxillofacial and Oral Surgery in Innsbruck, assessing a plethora of parameters such as injury type and mechanism as well as age and gender distribution over time. Three main groups of CMF trauma were evaluated: facial bone fractures, dentoalveolar trauma, and soft tissue injuries. Statistical comparisons were carried out using a chi-square test. This was followed by a logistic regression analysis to determine the impact of the five main causes for CMF injury. Older people were more prone to soft tissue lesions with a rising risk of 2.1% per year older, showing no significant difference between male and female patients. Younger patients were at higher risk of suffering from dentoalveolar trauma with an increase of 4.4% per year younger. This number was even higher (by 19.6%) for female patients. The risk of sustaining facial bone fractures increased each year by 4.6%. Male patients had a 66.4% times higher risk of suffering from this type of injury. In addition, 2550 patients (17.4%) suffered from 3834 concomitant injuries of other body parts. In summary, we observed changing patterns of CMF trauma over the last 15 years, paralleled by advances in refined treatment and management options for rehabilitation and reconstruction of patients suffering from CMF trauma.

The impact of distension pressure on acute endothelial cell loss and neointimal proliferation in saphenous vein grafts.

OBJECTIVES: We aimed to determine the extent of acute endothelial cell loss and neointimal proliferation in the long-term in saphenous vein grafts (SVGs) exposed to defined distension pressures. METHODS: During routine competence testing of SVGs for coronary artery bypass grafting (CABG), blinded peak pressure measurements were performed in 10 patients. In an experimental set-up, distension pressure-related endothelial damage was studied in the SVGs of 20 patients. In a subgroup (n = 10), each patient's SVG was divided into segments and subjected to four constant pressures (50, 100, 150 and 300 mmHg) for 30 min each. In another subgroup (n = 10), SVGs were exposed to a short phase of high pressure (low pressure followed by 300 mmHg for 5 min). Acute endothelial cell loss was quantified by CD31-immunostaining. After 2 weeks of organ culture, the neointimal proliferation was evaluated using histomorphometry. Pressure-related damage was compared with damage at baseline (0 mmHg). RESULTS: During routine competence testing for CABG, we revealed a median peak pressure of 355 mmHg (range: 240-639 mmHg). In the experimental set-up, significant acute endothelial cell loss occurred at all tested distension pressures: at 50 mmHg, the median endothelial cell loss was 29% (range: 20-51%, P = 0.015), at 100 mmHg 54% (range: 37-69%, P < 0.001), at 150 mmHg 75% (range: 41-88%, P < 0.001), at 300 mmHg 91% (range: 63-100%, P < 0.001) and at short high-pressure exposure 65% (range: 49-82%, P < 0.001) in comparison with 20% (range: 0-44%) at baseline. Significant neointimal proliferation occurred when a distension pressure of 50 mmHg was exceeded: at 50 mmHg, median neointimal proliferation was 97 µm (range: 60-380 µm, P = 0.176), at 100 mmHg 168 µm (range: 100-600 µm, P = 0.001), at 150 mmHg 183 µm (range: 160-440 µm, P < 0.001) at 300 mmHg 347 µm (range: 190-590 µm, P < 0.001) and at short high-pressure exposure 130 µm (range: 60-410 µm, P = 0.02) in comparison with 90 µm (range: 60-170 µm) at baseline. CONCLUSIONS: In vitro exposure of SVGs to low distension pressure ranges causes significant acute endothelial cell loss and crucial long-term damage, namely neointimal proliferation.

Everolimus attenuates neointimal hyperplasia in cultured human saphenous vein grafts.

OBJECTIVE: Neointimal hyperplasia is the first step in a cascade leading to a reduced patency rate of saphenous vein grafts in comparison to arterial grafts in coronary artery bypass grafting. Using cultured human saphenous vein grafts as a model for coronary artery bypass grafting, we investigated if the mammalian target of rapamycin inhibitor everolimus attenuates neointimal hyperplasia. METHODS: Saphenous vein grafts from 10 patients undergoing coronary artery bypass grafting were processed as follows: from each patient, one segment served as baseline control at day 0. Two segments were cultured in a neointimal hyperplasia model separately. One received no treatment and the other everolimus (1 microM). All vein grafts underwent histomorphometric analysis, assessment of proliferation by Ki-67 immunostaining and quantification of phospho-S6 ribosomal protein using western blot analysis. RESULTS: Everolimus treatment resulted in reduced neointimal hyperplasia (thickness 3.7+/-1.2 microm) compared to untreated controls (10.1+/-2.5 microm, p=0.008). The intima/intima+media-ratio was reduced in the everolimus group (0.10+/-0.02) compared to untreated controls (0.24+/-0.07, p=0.008). The number of Ki-67 positive proliferating cells in everolimus treated vein grafts (15+/-7 cells/high power field) showed a tendency of reduction compared to untreated controls (36+/-20 cells/high power field, p=0.036). Finally, everolimus treatment resulted in downregulation of S6 ribosomal protein phosphorylation in comparison to untreated controls. CONCLUSION: Everolimus is able to reduce neointimal proliferation in cultured human saphenous vein grafts by inhibition of the mammalian target of rapamycin, even though different transfection methods are to be evaluated for a clinical application in coronary artery bypass grafting.

Leoligin, the major lignan from Edelweiss, inhibits intimal hyperplasia of venous bypass grafts.

AIMS: Despite the lower patency of venous compared with arterial coronary artery bypass grafts, approximately 50% of grafts used are saphenous vein conduits because of their easier accessibility. In a search for ways to increase venous graft patency, we applied the results of a previous pharmacological study screening for non-toxic compounds that inhibit intimal hyperplasia of saphenous vein conduits in organ cultures. Here we analyse the effects and mechanism of action of leoligin [(2S,3R,4R)-4-(3,4-dimethoxybenzyl)-2-(3,4-dimethoxyphenyl)tetrahydrofuran-3-yl]methyl (2Z)-2-methylbut-2-enoat, the major lignan from Edelweiss (Leontopodium alpinum Cass.). METHODS AND RESULTS: We found that leoligin potently inhibits vascular smooth muscle cell (SMC) proliferation by inducing cell cycle arrest in the G1-phase. Leoligin induced cell death neither in SMCs nor, more importantly, in endothelial cells. In a human saphenous vein organ culture model for graft disease, leoligin potently inhibited intimal hyperplasia, and even reversed graft disease in pre-damaged vessels. Furthermore, in an in vivo mouse model for venous bypass graft disease, leoligin potently inhibited intimal hyperplasia. CONCLUSION: Our data suggest that leoligin might represent a novel non-toxic, non-thrombogenic, endothelial integrity preserving candidate drug for the treatment of vein graft disease.