Use of a fibrin-based system for enhancing angiogenesis and modulating inflammation in the treatment of hyperglycemic wounds

The complex pathophysiology of chronic ulceration in diabetic patients is poorly understood; diabetes-related lower limb amputation is a major health issue, which has limited effective treatment regimes in the clinic. This study attempted to understand the complex pathology of hyperglycemic wound healing by showing profound changes in gene expression profiles in wounded human keratinocytes in hyperglycemic conditions compared to normal glucose conditions. In the hyper-secretory wound microenvironment of hyperglycemia, Rab18, a secretory control molecule, was found to be significantly downregulated. Using a biomaterial platform for dual therapy targeting the two distinct pathways, this study aimed to resolve the major dysregulated pathways in hyperglycemic wound healing. To complement Rab18, and promote angiogenesis eNOS was also targeted, and this novel Rab18-eNOS therapy via a dynamically controlled ‘fibrin-in-fibrin’ delivery system, demonstrated enhanced wound closure, by increasing functional angiogenesis and reducing inflammation, in an alloxan-induced hyperglycemic preclinical ear ulcer model of compromised wound healing.     

The promotion of functional urinary bladder regeneration using anti-inflammatory nanofibers

Current attempts at tissue regeneration utilizing synthetic and decellularized biologic-based materials have typically been met in part by innate immune responses in the form of a robust inflammatory reaction at the site of implantation or grafting. This can ultimately lead to tissue fibrosis with direct negative impact on tissue growth, development, and function. In order to temper the innate inflammatory response, anti-inflammatory signals were incorporated through display on self-assembling peptide nanofibers to promote tissue healing and subsequent graft compliance throughout the regenerative process. Utilizing an established urinary bladder augmentation model, the highly pro-inflammatory biologic scaffold (decellularized small intestinal submucosa) was treated with anti-inflammatory peptide amphiphiles (AIF-PAs) or control peptide amphiphiles and used for augmentation. Significant regenerative advantages of the AIF-PAs were observed including potent angiogenic responses, limited tissue collagen accumulation, and the modulation of macrophage and neutrophil responses in regenerated bladder tissue. Upon further characterization, a reduction in the levels of M2 macrophages was observed, but not in M1 macrophages in control groups, while treatment groups exhibited decreased levels of M1 macrophages and stabilized levels of M2 macrophages. Pro-inflammatory cytokine production was decreased while anti-inflammatory cytokines were up-regulated in treatment groups. This resulted in far fewer incidences of tissue granuloma and bladder stone formation. Finally, functional urinary bladder testing revealed greater bladder compliance and similar capacities in groups treated with AIF-PAs. Data demonstrate that AIF-PAs can alleviate galvanic innate immune responses and provide a highly conducive regenerative milieu that may be applicable in a variety of clinical settings.     

A multicenter prospective trial to asses a new real-time polymerase chain reaction for detection of Treponema pallidum,herpes simplex-1/2 and Haemophilus ducreyi in genital,anal and oropharyngeal ulcers

Treponema pallidum, herpes simplex virus types 1 or 2 (HSV-1/2) and Haemophilus ducreyi are sexually transmitted pathogens that can cause genital, anal and oropharyngeal ulcers. Laboratory evaluation of these pathogens in ulcers requires different types of specimens and tests, increasing the risk of improper specimen handling and time lapse until analysis. We sought to develop a new real-time PCR (TP-HD-HSV1/2 PCR) to facilitate the detection of T. pallidum, HSV-1/2 and H. ducreyi in ulcers. The TP-HD-HSV1/2 PCR was tested (i) in a retrospective study on 193 specimens of various clinical origin and (ii) in a prospective study on 36 patients with genital, anal or oropharyngeal ulcers (ClinicalTrials.gov # NCT01688258). The results of the TP-HD-HSV1/2 PCR were compared with standard diagnostic methods (T. pallidum: serology, dark field microscopy; HSV-1/2: PCR; H. ducreyi: cultivation). Sensitivity and specificity of the TP-HD-HSV1/2 PCR for T. pallidum were both 100%, for HSV-1 100% and 98%, and for HSV-2 100% and 98%, respectively. T. pallidum and HSV-1/2 were detected in 53% and 22% of patients in the prospective study; H. ducreyi was not detected. In the prospective study, 5/19 (26%) specimens were true positive for T. pallidum in the TP-HD-HSV1/2 PCR but non-reactive in the VDRL. The TP-HD-HSV1/2 PCR is sensitive and specific for the detection of T. pallidum and HSV-1/2 in routine clinical practice and it appears superior to serology in early T. pallidum infections.     

Repair of Extensive Apical Root Resorption Associated with Apical Periodontitis: Radiographic and Histologic Observations after 25 Years

Introduction

Root resorption is a frequent finding in teeth with apical periodontitis. In cases of severe apical periodontitis, root resorption may involve not only cementum but also dentin. Resorbed tooth structures can only be repaired with cementum because stem cells in the periradicular tissues are not capable of differentiating into odontoblasts. This article reports the repair of extensive apical root resorption associated with apical periodontitis 25 years after treatment.

Methods

A 51-year-old man presented with pulp necrosis and symptomatic apical periodontitis in tooth #7. The periapical radiograph showed a large radiolucent periradicular lesion and severe root resorption. Nonsurgical root canal therapy was performed. Twenty-five years after treatment, a crown fracture developed, and the tooth could not be restored. The periapical radiograph revealed complete healing of the previous apical periodontitis lesion and restoration of the resorbed root structure. The tooth was removed and examined histologically.

Results

The apical canal was almost completely filled with a cementumlike tissue with some strands of entrapped vital uninflamed connective tissue. Areas of cementum and dentin resorption in the apical third were repaired by a combination of cellular and acellular cementum to which periodontal ligament fibers were attached.

Conclusions

Root resorption caused by apical periodontitis can be restored almost to its normal structure after adequate nonsurgical root canal treatment that succeeded in controlling infection. The mechanisms behind this process are not clear but probably involve signaling pathways regulating root development, cell-cell and cell-matrix interaction, and morphogens.     

Intermittent Parathyroid Hormone Administration Improves Periodontal Healing in Rats

Background: Intermittent administration of parathyroid hormone (PTH) promotes new bone formation in patients with osteoporosis and bone fractures. It was shown previously that PTH also reduces periodontitis‐related bone loss. The aim of this study is to evaluate the effect of treatment with PTH on periodontal healing in rats. Methods: Fenestration defects were created at the buccal surface of the distal root of the mandibular first molars, and both periodontal ligament (PDL) and cementum were removed. Animals were then assigned to two groups (eight animals per group): group 1: control, placebo administration; and group 2: test, human PTH (hPTH) 1‐34 administration at a concentration of 40 μg/kg. For both groups, the animals were injected every 2 days, and the animals were sacrificed at 14 and 21 days after surgery. Specimens were harvested and processed for routine decalcified histologic sections. The following parameters were assessed: 1) remaining bone defect extension (RBDE); 2) newly formed bone density (NFBD); 3) total callus area (TCA); 4) osteoclast number (ON) in the callus region; and 5) newly formed dental cementum‐like tissue (NFC). Birefringence of root PDL reattachment was also evaluated. Results: Birefringence analysis showed root PDL reattachment for both groups 21 days after treatment. Intermittent hPTH 1‐34 administration decreased RBDE (P <0.01) and increased NFBD (P <0.01), TCA (P <0.01), area of NFC (P <0.01), and ON in the callus region (P <0.01). Conclusion: Within the limits of the present study, intermittent administration of hPTH 1‐34 led to an enhanced periodontal healing process compared with non‐treated animals.     

Perioperative evaluation of glycaemic status in neck dissection: a retrospective analysis at a single hospital centre

Diabetes mellitus is generally considered a risk factor for impaired wound healing. This study aimed to evaluate the glycaemic status of patients undergoing neck dissection and describe its impact on postoperative outcomes, especially wound healing. A retrospective analysis was performed of the preoperative, intraoperative, and postoperative glycaemic data obtained from the medical charts of 60 adult patients who had undergone 64 neck dissections. Nine of the 64 procedures were performed in diabetic patients (14.1%). The average glucose values were: preoperative 5.99 ± 1.25 mmol/l, intraoperative 8.90 ± 2.62 mmol/l, and postoperative 10.01 ± 2.49 mmol/l. All registered preoperative hyperglycaemia cases (eight cases) were diabetic. Postoperative insulin therapy was done in 14 procedures (21.9%). Wound healing complications were found in five patients (7.8%); there was no wound infection. There was no association of wound healing complications with preoperative diabetic status (P = 1.000), preoperative glucose control (P = 1.000), preoperative (P = 0.469), intraoperative (P = 0.248), and postoperative (P = 0.158) glucose values, or with postoperative glucose control (P = 0.577). These data do not support the association of stress-induced hyperglycaemia or diabetes mellitus with postoperative wound healing problems in neck dissection.     

Therapeutic efficacy of antibiotic-loaded gelatin microsphere/silk fibroin scaffolds in infected full-thickness burns

Despite advances in burn treatment, burn infection remains a major cause of morbidity and mortality. In this study, an antibacterial silk fibroin (SF) scaffold for burn treatment was designed; gelatin microspheres (GMs) were impregnated with the antibiotic gentamycin sulfate (GS), and the GS-impregnated GMs were then embedded in a SF matrix to fabricate GS/GM/SF scaffolds. The developed GS/GM/SF scaffolds could serve as a dermal regeneration template in full-thickness burns. The average pore size and porosity of the GS/GM/SF scaffolds were 40–80 μm and 85%, respectively. Furthermore, the drug release rate of the scaffolds was significantly slower than that of either GS/GM or GS/SF scaffolds. And the composite scaffold exhibited stronger antimicrobial activities against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Hence, we evaluated the wound-healing effects and antibacterial properties of the GS/GM/SF scaffolds in a rat full-thickness burn infection model. Over 21 days, the GS/GM/SF scaffolds not only significantly reduced burn infection by P. aeruginosa but also accelerated the regeneration of the dermis and exhibited higher epithelialization rates than did GS/SF and SF scaffolds. Thus, GS/GM/SF scaffolds are potentially effective for treatment of full-thickness infected burns, and GS/GM/SF scaffolds are a promising therapeutic tool for severely burned patients.     

The in vitro characterization of a gelatin scaffold,prepared by cryogelation and assessed in vivo as a dermal replacement in wound repair

A sheet gelatin scaffold with attached silicone pseudoepidermal layer for wound repair purposes was produced by a cryogelation technique. The resulting scaffold possessed an interconnected macroporous structure with a pore size distribution of 131 ± 17 μm at one surface decreasing to 30 ± 8 μm at the attached silicone surface. The dynamic storage modulus (G′) and mechanical stability were comparable to the clinical gold standard dermal regeneration template, Integra®. The scaffolds were seeded in vitro with human primary dermal fibroblasts. The gelatin based material was not only non-cytotoxic, but over a 28 day culture period also demonstrated advantages in cell migration, proliferation and distribution within the matrix when compared with Integra®. When seeded with human keratinocytes, the neoepidermal layer that formed over the cryogel scaffold appeared to be more advanced and mature when compared with that formed over Integra®. The in vivo application of the gelatin scaffold in a porcine wound healing model showed that the material supports wound healing by allowing host cellular infiltration, biointegration and remodelling. The results of our in vitro and in vivo studies suggest that the gelatin based scaffold produced by a cryogelation technique is a promising material for dermal substitution, wound healing and other potential biomedical applications.     

Clinical and radiographic evaluation of the efficacy of platelet-rich plasma combined with hydroxyapatite bone graft substitutes in the treatment of intra-bony defects in maxillofacial region

Objective. The aim of this study is to evaluate the efficacy of platelet-rich plasma (PRP) clinically and radiographically when combined with bovine derived hydroxyapatite (HA) bone grafting materials and resorbable collagen membranes for the treatment of intra-bony defects frequently seen at the distal aspect of mandibular second molars following the surgical extraction of fully impacted mandibular wisdom teeth. Study design. Eighteen patients were scheduled for post-operative visits at 1, 3 and 6 months post-operatively, probing depths were measured and digital panoramic radiographs were taken. Results. There were no significant differences on probing depths among two groups. Radiographic assessment also showed no significant difference among groups at 1st and 6th month intervals, while 3 months post-operatively the amount of radiographic density at the PRP side was significantly higher. Conclusion. Combined use of PRP and bovine-derived HA graft materials for the treatment of intra-bony defects might be an appropriate approach when the main goal is providing earlier bone regeneration.