Evaluation of Wound Closure Rates Using a Human Fibroblast-derived Dermal Substitute Versus a Fetal Bovine Collagen Dressing: A Retrospective Study.

Diabetic foot ulcers (DFUs) are associated with an increased risk for serious and costly outcomes such as osteomyelitis, amputation, and hospitalization. PURPOSE: A retrospective study was conducted to evaluate the proportion of patients healed and time to healing of DFUs treated with a human fibroblast-derived dermal substitute (HFDS) or a fetal bovine collagen dressing (FBCD). METHODS: Data from patients with a DFU who received the first treatment in 2014 were extracted from the electronic record database of 93 wound care centers. Baseline demographics (eg, age, gender, body mass index, and number of wounds); wound location, size, and duration; and wound-specific information such as wound size and number of and interval between applications were obtained. Study criteria stipulated patients who received at least one treatment in 2014 with HFDS or FBCD on a DFU with location coded as foot, toe, heel, metatarsal head, toe web space, toe amputation site, or transmetatarsal amputation site; ulcer size ≥1 cm2 to <20 cm2; and ulcer area reduction ≤50% in the 28 days before the first treatment with HFDS or FBCD were eligible for inclusion. Wounds that received an alternate skin substitute treatment up to 28 days before or concurrent with the first HFDS or FBCD treatment or if patient data that lacked baseline or follow-up wound area measurement were excluded. Deidentified data were extracted directly into data files and transferred to a third-party data management and statistical group for analysis. The frequency of DFUs achieving wound closure (defined as area ≤0.25 cm2) by weeks 12 and 24 and median time to wound closure of wounds that healed were analyzed. Baseline characteristics were compared using 2-sample t tests for continuous variables and 2-tailed Fisher's exact tests for difference in proportions between treatments. Frequency of and median time to wound closure were determined by Cox proportional hazards analysis. The frequency of wounds closed at 12 and 24 weeks, median time to wound closure, hazard ratio with 95% confidence interval, and P value were estimated from the Cox model. Statistical significance was defined as P <.05. RESULTS: Records showed 206 patients with 208 DFUs received treatment (108 HFDS, mean age 60.2 years, mean wound duration 8.8 months; 100 FBCD, mean age 65.2 years, mean wound duration 12.8 months) and were included. Mean number of treatment applications was 4.5 and 2.4 for HFDS and FBCD, respectively. After 12 and 24 weeks 44 (41%) and 69 (64%) of HFDS-treated wounds, respectively, and 21 (21%) and 43 (43%) of FBCD-treated wounds, respectively, were healed (at 12 weeks, P = .03; at 24 weeks, P = .03, log rank 2-tailed test, unadjusted). Median time to wound closure for HFDS and FBCD was 14.6 and 25 weeks, respectively (P = .03; log rank, 2-tailed test; Kaplan-Meier analysis). HFDS treatment significantly increased the probability of wound healing compared to FBCD treatment in the Cox proportional hazards analysis after adjusting for treatment terms, baseline wound area, baseline wound duration, baseline wound depth, wound location, and patient age at first treatment (HR = 1.77; 95% CI: 1.06-2.97; P = .03). CONCLUSION: DFU wounds are more likely to heal when treated with HFDS than with FBCD as used by facilities in this database. Studies examining the efficacy, cost-effectiveness, and patient-centered outcomes of these treatments is warranted. .

Cellular and collagen reference values of gingival and periodontal ligament tissues in rats: a pilot study.

Reference data are lacking on the periodontal ligament and the gingival tissue of the rat model, which would be useful for studies of new medical or biomaterial periodontal treatments. The objective of the current study was to propose cellular and collagen reference values of gingival and periodontal ligament tissues in rat, using a simple and reliable quantitative method after decalcification. Mandibular samples of ten adult Sprague-Dawley rats were used. Mild decalcification was carried out using ethylenediaminetetraacetic acid (EDTA) to preserve the morphology of tissues. Half of the samples were decalcified and the other half were not. The gingiva and the periodontal ligament were analyzed. Descriptive histology and computer-assisted image analysis were performed. The data showed that qualitatively, cellular and extracellular matrix morphologies were well preserved compared to non-decalcified periodontal soft tissue biopsies. Histomorphometrically, constitutive cellularity and the total amount of native collagen, collagen directionality and collagen anisotropy in both experimental conditions did not significantly differ. Taken together, these results suggested that EDTA decalcification did not negatively affect the studied endpoints. Moreover, this mild decalcification method allowed in situ maintenance of the periodontal soft and hard tissue integrity. The structural and compositional computerized assessment performed in the healthy periodontal soft tissue could provide reference values that will be required for future assessment on the effects of pathological, reparative and regenerative processes in rat periodontal soft tissues.

Biocompatibility of membranes with unrestricted somatic stem cells.

AIM: The biocompatibility of human osteoblasts (HOB) and human unrestricted somatic stem cells (USSCs) with membranes (BioGide®, GORE-TEX®, GENTA-FOIL resorb®, RESODONT®, BioMend®, BioMend® Extend™) was evaluated. MATERIALS AND METHODS: After osteogenic differentiation (dexamethasone, ascorbic acid and ß-glycerolphosphate) cells were seeded on membranes. On days 1, 3 and 7, attachment, proliferation, cell vitality, cytotoxicty and cell morphology were analyzed. RESULTS: Cells on BioGide® and RESODONT® exhibited significantly higher attachment (p<0.005) and proliferation (p<0.005). On BioMend® cells showed a significantly higher attachment compared to BioMend® Extend™ (p<0.005), whereas on BioMend® Extend™ cells had significantly higher proliferation (p<0.005). The vitality of cells was significantly better on BioGide® and RESODONT® (p<0.005). There were no significant differences between USSCs and HOBs. Scanning electron microscopy confirmed these results. CONCLUSION: BioGide® and RESODONT® had the best biocompatibility and are appropriate membranes for use in stem cell-derived regeneration of bone.

An acetic acid-based extraction method to obtain high quality collagen from archeological bone remains.

Human bones, recovered from excavations, are an important biological archive of information. In particular, the analysis of the collagen fraction is useful for paleodietary reconstruction, via light stable isotopes, and for (14)C dating. Generally, collagen extraction procedures do not prevent loss of integrity of proteins. As a consequence, information about the state-of-remains preservation is unavailable. Here we describe a "soft" nondestructive CH(3)COOH-based method to recover collagen from archaeological bones, and also to obtain material for successive isotopic analyses. Our isotopic measurements on the extracts indicate that the CH(3)COOH-based method of extraction may be routinely employed in the context of paleodiet studies. In addition, we propose that biochemical characterization by denaturant electrophoresis and Western blot on CH(3)COOH extracts may be used as a bone collagen quality indicator.

Safety and effectiveness of hyaluronic acid fillers in skin of color.

OBJECTIVES: To assess the safety and effectiveness of hyaluronic acid (HA) fillers in skin of color. METHODS: Two prospective studies followed up subjects with Fitzpatrick skin phototypes of IV, V, or VI for 24 weeks after dermal filler injections. In a double-blind, randomized study, subjects were injected with one of three high concentration (24 mg/mL) HA fillers (Juvéderm Ultra, Ultra Plus, and 30) in one nasolabial fold and Zyplast collagen in the other. In an open-label, randomized study, subjects received one of three low concentration (5.5 mg/mL) HA fillers (Hylaform, Hylaform Plus, and Captique) in both nasolabial folds. RESULTS: A total of 160 subjects (a subset of 439 study subjects) were randomized and treated with one of the three high concentration fillers, and 119 subjects were randomized and treated with one of the three low concentration fillers. For subjects treated with the high concentration fillers there were no occurrences of hypersensitivity or hypertrophic scarring, and no increased incidence of hyperpigmentation or hypopigmentation in non-Caucasian vs. Caucasian subjects. For subjects treated with the low concentration fillers there were no occurrences of keloid formation, hypertrophic scarring, hypopigmentation, hypersensitivity, and three instances of mild hyperpigmentation. For all of the fillers the majority of subjects maintained >/=1 point improvement in nasolabial fold severity scores through 24 weeks. CONCLUSIONS: All of the HA fillers were well tolerated in individuals with skin of color and demonstrated effectiveness throughout the 24 week period. Furthermore, the fillers provided smooth, natural-looking wrinkle correction in darker skin types.

Confocal laser scanning microscopy using dialkylcarbocyanine dyes for cell tracing in hard and soft biomaterials.

The aim of this work was to study, in vitro, cell colonization of two biomaterials currently used for bone and cartilage repair, this step being important to understand the function of engineered tissues. Current methods that use histological approaches are not always suited to tissue-engineering analysis. We, therefore, set up a protocol to assess cell distribution, utilizing noninvasive confocal microscopy and fluorescent labels with a far red emission wavelength to optimize scaffold transparency and minimize light scattering. Hard (ceramic substitute) and soft (collagen sponge) biomaterials were seeded respectively, on one side of the scaffold, with human fibroblasts and bovine chondrocytes labelled with carbocyanine dyes (DiD and DiR). The mean penetration depth for DiR labelled fibroblasts and chondrocytes in the two scaffolds, around 270 m, was greater than for DiD (136-218 microm) labelled cells. These depths were independent of cell origin but were influenced by the nature of the scaffolds. Collagen sponge is transparent in contrast to ceramic substitutes where measurements could only be made in opened macropores. Besides the limits of the equipment, the limits of the supports were diffusion for collagen sponges and transmission for ceramic substitutes. Confocal microscopy techniques could thus be used to address the question of cell colonization of porous biomaterials in a noninvasive manner.

Global regulatory registration requirements for collagen-based combination products: points to consider.

Collagen-based medical products provide an ideal and unique matrix for the delivery of drugs, biologics and other therapeutic agents. Collagen has a long history of safety and effectiveness. Collagen is biodegradable with minimal tissue reaction. Regulatory requirements for approval of collagen-based combination products are changing as more high technology combinations are developed. There are special considerations that need to be addressed for collagen products. Products of animal origin must meet specific requirements in regards to safety factors regarding Transmissable Spongiform Encephalopathies. Global regulatory registration requirements and special controls are presented.

[Mechanical properties of biological or synthetic implants used to treat genital prolapse and stress incontinence in women : what is the ideal material?]. / Propriétés mécaniques des implants biologiques ou synthétiques utilisés dans les cures de prolapsus et d'incontinence urinaire de la femme: quel est le matériau idéal?

INTRODUCTION: Many surgical techniques proposed for genital prolapse or stress incontinence use prosthetic material to reinforce native tissues. Most of the synthetic meshes used have been designed for hernia repair. MATERIAL AND METHOD: We study the biomechanical properties of human Alloderm or animals tissues like Pelvicol and of synthetic resorbable and permanent meshes. We report the results from the literature. We report the results of a personal study of the biomechanical properties of synthetic meshes. RESULTS: The literature on biomechanical properties of biological or synthetic meshes and their evolution after implantation is sparse. Biogyn ITY or Prolène are the only meshes without spatial orientation. Their resistance to rupture and mechanical properties are variable and seem poor for Biogyn W8 et Mersuture. DISCUSSION: Reviewing the literature we discuss the ideal properties for synthetic meshes used for cure of genital prolapse.

Measurement of serum beta-crosslaps is influenced by proteolytic conditions.

Serum beta-crosslaps are an established laboratory test to investigate bone metabolism. However, lytic conditions may affect the measurement of serum beta-crosslaps. Therefore, we investigated the effect of cathepsin C and human leukocyte lysate on serum beta-crosslaps in relation to temperature and time. We divided eight serum samples with elevated beta-crosslaps levels into three aliquots and stored them at 4, 21 and 37 degrees C. Another five serum samples were divided into three aliquots and adjusted to contain different cathepsin C concentrations (50, 250, 500 IU/l). These aliquots were divided again and stored at 4, 21 and 37 degrees C. Finally, three aliquots from three additional serum samples were treated with human leukocyte lysate (100, 300, 500 microl), divided again and stored at 4, 21 and 37 degrees C. Measurements of serum beta-crosslaps were then carried out before and immediately after manipulation, and after 2 and 5 days of storage. When stored at 21 degrees C, serum beta-crosslaps diminished significantly (25% after 5 days), but no significant change was detectable when they were stored at 4 degrees C. Cathepsin C induced up to a 14% increase in beta-crosslaps while human leukocyte lysate caused up to a 17% decrease. This study demonstrates that the influence of proteolytic conditions on the serum concentration of beta-crosslaps is not uniform. Leukocyte lysate decreased serum beta-crosslaps while the addition of cathepsin C increased their concentration. Therefore, serum should be separated from the whole blood immediately after coagulation and stored until analysis in a deep freezer.

[Evaluation of blood absorption, hemostatic ability and purity of a polyepoxy compound cross-linked cotton type collagen hemostat].

A polyepoxy compound cross-linked cotton type collagen hemostat (CCH) made of highly purified atelocollagen in a fine filament shape was developed. To evaluate blood absorption, hemostatic ability and purity of the CCH, Avitene and Oxycel were used for comparison. Blood absorption speed of the CCH was faster than Avitene and Oxycel. The handling characteristics of the CCH were much better than those of Avitene and Oxycel. Hemostatic ability was better in the CCH compared to Avitene in a canine study. The purity of the CCH was better than in Avitene which contained albumin and other proteins. Those results suggest that the developed hemostat with excellent blood absorption, handling characteristics, hemostatic ability and purity, could be useful in clinicals.

Injectable soft tissue substitutes.

Historical and modern advances in the development of an injectable soft tissue substitute are reviewed. Nonbiologic alloplastic and biologic injectables are described. The authors' experiences, as well as those of others, employing presently available materials in terms of specific indications and special techniques are delineated. The search for a safe, effective, easy-to-use, and long-lasting soft tissue substitute continues.

Liquid crystallinity in condensed type I collagen solutions. A clue to the packing of collagen in extracellular matrices.

We recently described a new type of assembly of collagen molecules, forming typical liquid crystalline phases in highly concentrated solutions after sonication. The present work shows that intact 300 nm long collagen molecules also form cholesteric liquid crystalline domains, but the time required is much longer, several weeks instead of several days. Differential calorimetry and X-ray diffraction show that sonication does not alter the triple-helical structure of the collagen fragments. In the viscous solutions, observed between crossed polars in optical microscopy, the textures vary as a function of the concentration. Molecules first align near the air interface at the coverslip edge, then as the concentration increases by slow evaporation of the solvent, the birefringence extends inwards and liquid crystalline domains progressively appear. For concentrations estimated to be above 100 mg/ml, typical textures and defects of cholesteric phases are obtained, at lower concentrations zig-zag extinction patterns and banded patterns are observed; all these textures are described and interpreted. The cholesteric packing of collagen fibrils in various extracellular matrices is known, and the relationship that can be made between the ordered phases obtained with collagen molecules in vitro and the related geometrical structures observed between fibrils in vivo is thoroughly discussed.

A highly specific and quantitative method for determining type III/I collagen ratios in tissues.

The distribution of type I and type III collagens in rat, bovine and human skin were examined by a quantitative 2-D CNBr peptide mapping method. The procedure involved the solubilization of tissues by digestion with CNBr, radioactive labeling in vitro by [3H]-NaBH4 in dimethylformamide, reduction by mercaptoethanol, a second CNBr digestion and 2-D (isoelectric focusing and NaDodSO4 electrophoresis) mapping. The amounts of type I and type III collagen peptide spots in the fluorographs of 2-D maps were analyzed by 2-D scanning densitometer/analyzer. Mixtures containing various ratios of purified type I and type III collagen were used to obtain a standard curve. Using this procedure we were able to determine that in adult human skin (age range 35-65 years) 22% (+1.3%) of the labelled collagen is type III. This value is significantly higher than that was previously estimated by less accurate methods.

Reconstituted bovine skin collagen enhances healing of bone wounds in the rat calvaria.

The value of reconstituted fibrillar collagen (Zyderm Collagen Implant I, a concentrated solution of pepsin-solubilized, bovin skin collagen) as a bone graft material was tested in 4 mm diameter surgically created defects of rat calvaria. All wounds were allowed to heal for 4 weeks, and were assessed both qualitatively and by computer-assisted morphometry. The fibrillar collagen was found to produce significantly more new bone than no graft or than heat-denatured fibrillar collagen. The fibrillar collagen was generally well tolerated, appeared to act as a hospitable osteoconductor, and became incorporated into the newly formed bone. The effect of collagen concentration was also tested by comparing the fibrillar collagen at 3.5% (Zyderm Collagen Implant I) with 6.5% suspension of collagen (Zyderm Collagen Implant II). There were no significant differences observed, but a definite trend was evident for Zyderm II to encourage more bone formation than Zyderm I. It is concluded that reconstituted fibrillar collagen is a hospitable, osteoconductive substance that enhances bone healing of calvarial defects in the rat.