A model for the role of hyaluronic acid and fibrin in the early events during the inflammatory response and wound healing

"Filler-Associated Acute Stroke Syndrome": Classification, Predictive Modelling of Hyaluronidase Efficacy, and Updated Case Review on Neurological and Visual Complications

INTRODUCTION

The rising use of soft tissue fillers for aesthetic procedures has seen an increase in complications, including vascular occlusions and neurological symptoms that resemble stroke. This study synthesizes information on central nervous system (CNS) complications post-filler injections and evaluates the effectiveness of hyaluronidase (HYAL) treatment.

METHODS

A thorough search of multiple databases, including PubMed, EMBASE, Scopus, Web of Science, Google Scholar, and Cochrane, focused on publications from January 2014 to January 2024. Criteria for inclusion covered reviews and case reports that documented CNS complications related to soft tissue fillers. Advanced statistical and computational techniques, including logistic regression, machine learning, and Bayesian analysis, were utilized to dissect the factors influencing therapeutic outcomes.

RESULTS

The analysis integrated findings from 20 reviews and systematic analyses, with 379 cases reported since 2018. Hyaluronic acid (HA) was the most commonly used filler, particularly in nasal region injections. The average age of patients was 38, with a notable increase in case reports in 2020. Initial presentation data revealed that 60.9% of patients experienced no light perception, while ptosis and ophthalmoplegia were present in 54.3 and 42.7% of cases, respectively. The statistical and machine learning analyses did not establish a significant linkage between the HYAL dosage and patient recovery; however, the injection site emerged as a critical determinant.

CONCLUSION

The study concludes that HYAL treatment, while vital for managing complications, varies in effectiveness based on the injection site and the timing of administration. The non-Newtonian characteristics of HA fillers may also affect the incidence of complications. The findings advocate for tailored treatment strategies incorporating individual patient variables, emphasizing prompt and precise intervention to mitigate the adverse effects of soft tissue fillers.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Exploring the role of dermal sheath cells in wound healing and fibrosis

Wound healing is a complex, dynamic process involving the coordinated interaction of diverse cell types, growth factors, cytokines, and extracellular matrix components. Despite emerging evidence highlighting their importance, dermal sheath cells remain a largely overlooked aspect of wound healing research. This review explores the multifunctional roles of dermal sheath cells in various phases of wound healing, including modulating inflammation, aiding in proliferation, and contributing to extracellular matrix remodelling. Special attention is devoted to the paracrine effects of dermal sheath cells and their role in fibrosis, highlighting their potential in improving healing outcomes, especially in differentiating between hairy and non-hairy skin sites. By drawing connections between dermal sheath cells activity and wound healing outcomes, this work proposes new insights into the mechanisms of tissue regeneration and repair, marking a step forward in our understanding of wound healing processes.

Thermo-assisted fabrication of a novel shape-memory hyaluronic acid sponge for non-compressible hemorrhage control

Hyaluronic acid (HA), a major component of skin extracellular matrix, provides an excellent framework for hemostatic design; however, there still lacks HA materials tailored with superior mechanical properties to address non-compressible hemorrhages. Here, we present a solvent-free thermal approach for constructing a shape-memory HA sponge for this application. Following facile thermal incubation around 130 °C, HA underwent cross-linking via esterification with poly(acrylic acid) within the sponge pre-shaped through a prior freeze-drying process. The resulting sponge system exhibited extensively interconnected macropores with a high fluid absorption capacity, excellent shape-memory property, and robust mechanical elasticity. When introduced to whole blood in vitro, the HA sponges demonstrated remarkable hemostatic properties, yielding a shorter coagulation time and lower blood clotting index compared to the commercial gelatin sponge (GS). Furthermore, in vivo hemostatic studies involving two non-compressible hemorrhage models (rat liver volume defect injury or femoral artery injury) achieved a significant reduction of approximately 64% (or 56%) and 73% (or 70%) in bleeding time and blood loss, respectively, which also outperformed GS. Additionally, comprehensive in vitro and in vivo evaluations suggested the good biocompatibility and biodegradability of HA sponges. This study highlights the substantial potential for utilizing the designed HA sponges in massive bleeding management.

Purification and characterization of the produced hyaluronidase by Brucella Intermedia MEFS for antioxidant and anticancer applications

Hyaluronidase (hyase) is an endoglycosidase enzyme that degrades hyaluronic acid (HA) and is mostly known to be found in the extracellular matrix of connective tissues. In the current study, eleven bacteria isolates and one actinomycete were isolated from a roaster comb and screened for hyase production. Seven isolates were positive for hyase, and the most potent isolate was selected based on the diameter of the transparent zone. Based on the morphological, physiological, and 16 S rRNA characteristics, the most potent isolate was identified as Brucella intermedia MEFS with accession number OR794010. The environmental conditions supporting the maximum production of hyase were optimized to be incubation at 30 ºC for 48 h and pH 7, which caused a 1.17-fold increase in hyase production with an activity of 84 U/mL. Hyase was purified using a standard protocol, including precipitation with ammonium sulphate, DEAE as ion exchange chromatography, and size exclusion chromatography using Sephacryle S100, with a specific activity of 9.3-fold compared with the crude enzyme. The results revealed that the molecular weight of hyase was 65 KDa, and the optimum conditions for hyase activity were at pH 7.0 and 37 °C for 30 min. The purified hyase showed potent anticancer activities against colon, lung, skin, and breast cancer cell lines with low toxicity against normal somatic cells. The cell viability of hyase-treated cancer cells was found to be in a dose dependent manner. Hyase also controlled the growth factor-induced cell cycle progression of breast cancer cells and caused relative changes in angiogenesis-related genes as well as suppressed many pro-inflammatory proteins in MDA cells compared with 5-fluorouracil, indicating the significant role of hyase as an anticancer agent. In addition, hyase recorded the highest DPPH scavenging activity of 65.49% and total antioxidant activity of 71.84% at a concentration of 200 µg/mL.

Development of a bioactive silk fibroin bilayer scaffold for wound healing and scar inhibition

In cases of deep skin defects, spontaneous tissue regeneration and excessive collagen deposition lead to hyperplastic scars. Conventional remedial action after scar formation is limited with a high recurrence rate. In this study, we designed a new artificial skin bilayer using silk fibroin nanofibers films (SNF) as the epidermis, and silk fibroin (SF) / hyaluronic acid (HA) scaffold as the dermal layer. The regenerated SF film was used as a binder to form a functional SNF-SF-HA bilayer scaffold. The bilayer scaffold showed high porosity, hydrophilicity, and strength, and retained its shape over 30 days in PBS. In vitro, human umbilical vein endothelial cells were seeded into the bilayer scaffold and showed superior cell viability. In vivo analyses using the rabbit ear hypertrophic scar (HS) model indicated that the bilayer scaffold not only supported the reconstruction of new tissue, but also inhibited scar formation. The scaffold possibly achieved scar inhabitation by reducing wound contraction, weakening inflammatory reactions, and regulating collagen deposition and type conversion, which was partly observed through the downregulation of type I collagen, transforming growth factor-β, and α-smooth muscle actin. This study describes a new strategy to expand the application of silk-based biomaterials for the treatment of hyperplastic skin scars.

Platelet Rich Plasma Loaded Multifunctional Hydrogel Accelerates Diabetic Wound Healing via Regulating the Continuously Abnormal Microenvironments

Continuous oxidative stress and cellular dysfunction caused by hyperglycemia are distinguishing features of diabetic wounds. It has been a great challenge to develop a smart dressing that can accelerate diabetic wound healing through regulating abnormal microenvironments. In this study, a platelet rich plasma (PRP) loaded multifunctional hydrogel with reactive oxygen species (ROS) and glucose dual-responsive property is reported. It can be conveniently prepared with PRP, dopamine (DA) grafted alginate (Alg-DA), and 6-aminobenzo[c][1,2]oxaborol-1(3H)-ol (ABO) conjugated hyaluronic acid (HA-ABO) through ionic crosslinks, hydrogen-bond interactions, and boronate ester bonds. The hydrogel possesses injectability, moldability, tissue adhesion, self-healing, low hemolysis, and hemostasis performances. Its excellent antioxidant property can create a low oxidative stress microenvironment for other biological events. Under an oxidative stress and/or hyperglycemia state, the hydrogel can degrade at an accelerated rate to release a variety of cytokines derived from activated blood platelets. The result is a series of positive changes that are favorable for diabetic wound healing, including fast anti-inflammation, activated macrophage polarization toward M2 phenotype, promoted migration and proliferation of fibroblasts, as well as expedited angiogenesis. This work provides an efficient strategy for chronic diabetic wound management and offers an alternative for developing a new-type PRP-based bioactive wound dressing.

The Contribution of Vascular Proteoglycans to Atherothrombosis: Clinical Implications

The vascular extracellular matrix (ECM) produced by endothelial and smooth muscle cells is composed of collagens and glycoproteins and plays an integral role in regulating the structure and function of the vascular wall. Alteration in the expression of these proteins is associated with endothelial dysfunction and has been implicated in the development and progression of atherosclerosis. The ECM composition of atherosclerotic plaques varies depending on plaque phenotype and vulnerability, with distinct differences observed between ruptured and erodes plaques. Moreover, the thrombi on the exposed ECM are diverse in structure and composition, suggesting that the best antithrombotic approach may differ depending on plaque phenotype. This review provides a comprehensive overview of the role of proteoglycans in atherogenesis and thrombosis. It discusses the differential expression of the proteoglycans in different plaque phenotypes and the potential impact on platelet function and thrombosis. Finally, the review highlights the importance of this concept in developing a targeted approach to antithrombotic treatments to improve clinical outcomes in cardiovascular disease.

Stem cell and tissue engineering approaches in pressure ulcer treatment

CONTEXT

Pressure ulcers or injuries, arise from ischemic damage to soft tissues induced by unrelieved pressure over a bony prominence. They are usually difficult to treat with standard medical therapy and often they recur. In the search for better treatment options, promising alternative forms of treatment are today emerging. Within the field of regenerative medicine, ongoing research on advanced therapies seeks to develop medicinal products based on gene therapy, somatic cell therapy, tissue-engineering and combinations of these.

OBJECTIVE

The main objective is to perform an overview of experimental and clinical developments in somatic cell therapy and tissue engineering targeting the treatment of pressure injuries.

METHODS

Searching terms as "PRESSURE ULCER", "STEM CELL THERAPY", "TISSUE ENGINEERING" or "WOUND HEALING" were used in combination or alone, including publications refered to basic and clinical research and focusing on articles showing results obtained in a clinical context. A total of 80 references are cited, including 23 references published in the 3 last years.

RESULTS

The results suggest that this form of treatment could be an interesting option in patients with difficult-to-treat ulcers as spinal cord injury patients.

CONCLUSION

This field of regenerative medicine is very broad and further research is warranted.

Hyaluronic acid detection and relative quantification by mass spectrometry imaging in human skin tissues

Hyaluronic acid (HA) is a major component of the skin, contributing to tissue hydration and biomechanical properties. As HA content in the skin decreases with age, formulas containing HA are widely used in cosmetics and HA injections in aesthetic procedures to reduce the signs of aging. To prove the beneficial effects of these treatments, efficient quantification of HA levels in the skin is necessary, but remains difficult. A new analytical method has been developed based on matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to quantify HA content in cross sections of human skin explants. A standardized and reproducible chemical entity (3 dimeric motifs or 6-mer) quantifiable by MALDI-MSI was produced by enzymatic hydrolysis using a specific hyaluronidase (H1136) in HA solution. This enzymatic digestion was carried out on skin sections before laser desorption, enabling the detection of HA. Histological coloration allowed us to localize the epidermis and the dermis on skin sections and, by comparison with the MALDI molecular image, to calculate the relative HA concentrations in these tissue areas. Skin explants were treated topically using a formula containing HA or its placebo, and the HA distribution profiles were compared with those obtained from untreated explants. A significant increase in HA was shown in each skin layer following topical application of the formula containing HA versus placebo and untreated samples (average of 126±40% and 92±40%, respectively). The MALDI-MSI technique enabled the quantification and localization of all HA macromolecules (endogenous and exogenous) on skin sections and could be useful for determining the efficacy of new cosmetic products designed to fight the signs of aging.

Bioactive Phytochemicals of Citrus reticulata Seeds—An Example of Waste Product Rich in Healthy Skin Promoting Agents

Phytochemical investigation of Egyptian mandarin orange (Citrus reticulata Blanco, F. Rutaceae) seeds afforded thirteen known compounds, 1–13. The structures of isolated compounds were assigned using 1D and 2D NMR and HRESIMS analyses. To characterize the pharmacological activity of these compounds, several integrated virtual screening-based and molecular dynamics simulation-based experiments were applied. As a result, compounds 2, 3 and 5 were putatively identified as hyaluronidase, xanthine oxidase and tyrosinase inhibitors. The subsequent in vitro testing was done to validate the in silico-based experiments to highlight the potential of these flavonoids as promising hyaluronidase, xanthine oxidase and tyrosinase inhibitors with IC50 values ranging from 6.39 ± 0.36 to 73.7 ± 2.33 µM. The present study shed light on the potential of Egyptian mandarin orange’s waste product (i.e., its seeds) as a skin health-promoting natural agent. Additionally, it revealed the applicability of integrated inverse docking-based virtual screening and MDS-based experiments in efficiently predicting the biological potential of natural products.

Management of osteoarthritis: From drug molecules to nano/micromedicines

With the change in lifestyle and aging of the population, osteoarthritis (OA) is emerging as a major medical burden globally. OA is a chronic inflammatory and degenerative disease initially manifesting with joint pain and eventually leading to permanent disability. To date, there are no drugs available for the definitive treatment of osteoarthritis and most therapies have been palliative in nature by alleviating symptoms rather than curing the disease. This coupled with the vague understanding of the early symptoms and methods of diagnosis so that the disease continues as a global problem and calls for concerted research efforts. A cascade of events regulates the onset and progression of osteoarthritis starting with the production of proinflammatory cytokines, including interleukin (IL)‐1β, IL‐6, tumor necrosis factor (TNF)‐α; catabolic enzymes, such as matrix metalloproteinases (MMPs)‐1, ‐3, and ‐13, culminating into cartilage breakdown, loss of lubrication, pain, and inability to load the joint. Although intra‐articular injections of small and macromolecules are often prescribed to alleviate symptoms, low residence times within the synovial cavity severely impair their efficacy. This review will briefly describe the factors dictating the onset and progression of the disease, present the current clinically approved methods for its treatment and diagnosis, and finally elaborate on the main challenges and opportunities for the application of nano/micromedicines in the treatment of osteoarthritis. Thus, future treatment regimens will benefit from simultaneous consideration of the mechanobiological, the inflammatory, and tissue degradation aspects of the disease.

This article is categorized under:

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology

Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement

Actuation-Augmented Biohybrid Robot by Hyaluronic Acid-Modified Au Nanoparticles in Muscle Bundles to Evaluate Drug Effects

Biohybrid robots, which comprise soft materials with biological components, have the potential to sense, respond, and adapt to changing environmental loads dynamically. Instead of humans and other living things, biohybrid robots can be used in various fields such as drug screening and toxicity assessment. In the actuation part, however, since a muscle cell-based biohybrid robot is limited in that the driving force is weak, it is difficult to evaluate drug and toxicological effects by distinguishing changes in the biohybrid robot's motion. To overcome this limitation, we introduced hyaluronic acid-modified gold nanoparticles (HA-AuNPs) into a muscle bundle-based biohybrid robot that moves forward in response to electrical stimulation. To enhance the actuation of muscle bundles, HA-AuNPs were embedded into the muscle bundles. The motion of the fabricated biohybrid robot was improved due to the enhanced differentiation and the improved electrical conductivity of muscle bundles by HA-AuNPs. In addition, the fabricated biohybrid robot exhibited huge changes in motion with respect to the addition of positive and negative inotropic drugs. The proposed biohybrid robot has the potential for neuromuscular disease drug screening by incorporating nervous tissues such as motor neuron organoids and brain organoids.

Design, Synthesis, Characterization, and In Vitro Evaluation of a New Cross-Linked Hyaluronic Acid for Pharmaceutical and Cosmetic Applications

Hyaluronic acid (HA), an excellent biomaterial with unique bio properties, is currently one of the most interesting polymers for many biomedical and cosmetic applications. However, several of its potential benefits are limited as it is rapidly degraded by hyaluronidase enzymes. To improve the half-life and consequently increase performance, native HA has been modified through cross-linking reactions with a natural and biocompatible amino acid, Ornithine, to overcome the potential toxicity commonly associated with traditional linkers. 2-chloro-dimethoxy-1,3,5-triazine/4-methylmorpholine (CDMT/NMM) was used as an activating agent. The new product (HA–Orn) was extensively characterized to confirm the chemical modification, and rheological analysis showed a gel-like profile. In vitro degradation experiments showed an improved resistance profile against enzymatic digestions. Furthermore, in vitro cytotoxicity studies were performed on lung cell lines (Calu-3 and H441), which showed no cytotoxicity.

Advances in Skin Wound and Scar Repair by Polymer Scaffolds

Scars, as the result of abnormal wound-healing response after skin injury, may lead to loss of aesthetics and physical dysfunction. Current clinical strategies, such as surgical excision, laser treatment, and drug application, provide late remedies for scarring, yet it is difficult to eliminate scars. In this review, the functions, roles of multiple polymer scaffolds in wound healing and scar inhibition are explored. Polysaccharide and protein scaffolds, an analog of extracellular matrix, act as templates for cell adhesion and migration, differentiation to facilitate wound reconstruction and limit scarring. Stem cell-seeded scaffolds and growth factors-loaded scaffolds offer significant bioactive substances to improve the wound healing process. Special emphasis is placed on scaffolds that continuously release oxygen, which greatly accelerates the vascularization process and ensures graft survival, providing convincing theoretical support and great promise for scarless healing.

The Procoagulant Activity of Emoxilane®: A New Appealing Therapeutic Use in Epistaxis of the Combination of Sodium Hyaluronate, Silver Salt, α-tocopherol and D-panthenol

Epistaxis is one of the most frequent hemorrhages resulting from local or systemic factors. Its management without hospitalization has prompted an interest in locally applied hemostatic agents. Generally, the therapy approaches involve sprays or creams acting as a physical barrier, even used as tampons or gauze. In this study, we have investigated the activity of Emoxilane^®, a combination of sodium hyaluronate, silver salt, α-tocopherol acetate and D-panthenol, which is known to be able to separately act in a different biological manner. Our in vitro results, obtained on endothelial and nasal epithelial cells, have shown that the association of these molecules presented a notable antioxidant activity mainly due to the α-tocopherol and D-panthenol and a significant antimicrobial role thanks to the silver compound. Moreover, remarkable hemostatic activity was found by evaluating plasmin inhibition attributable to the sodium hyaluronate. Interestingly, on human plasma, we have confirmed that Emoxilane^® strongly induced the increase of thrombin levels. These data suggest that the use of this association could represent an appealing pharmacological approach to actively induce hemostasis during epistaxis. Our future perspective will aim to the creation of a formulation for an easy topical application in the nose which is able to contrast the bleeding.

The role of VEGF, PDGF and IL-6 on diabetic foot ulcer after Platelet Rich Fibrin + hyaluronic therapy

BACKGROUND

Current standard management of diabetic foot ulcers (DFUs) consists of surgical debridement followed by soak NaCl 0.9% gauzes tight infection and glycaemic control. Nowadays the use of advanced platelet-rich fibrin (A-PRF) has emerged as an adjunctive method for treating DFUs. This study was conducted to demonstrate the ability of combine A-PRF + HA as a complementary therapy in DFUs healing related with angiogenesis,inflammation and granulation index process.

METHODS

This open label randomized controlled trial was conducted in Koja District Hospital and Gatot Soebroto Hospital Jakarta, Indonesia on July 2019-April 2020. DFUs patients with wound duration of three months, Wagner-2, with size of ulcer less than 40 cm2 were included in the study. The number of subjects was calculated based on the rule of thumb and allocated randomly into three groups, namely topical A-PRF + HA, A-PRF and Sodium Chloride 0.9% as a control, for each of 10 subjects. A-PRF made by 10 mL venous blood, centrifuge 200 G in 10 min, meanwhile A-PRF + HA though mix both them with vertex machine around 5 min. Biomarker such as VEGF, PDGF and IL-6 examined from DFU taken by cotton swab and analysis using ELISA. Granulation Index was measured using ImageJ. Biomarkers and granulation index were evaluated on day 0, 3, 7 and 14. Data were analysed using SPSS version 20 with Anova and Kruskal Wallis test to compare the angiogenesis and inflammation effect between the three groups.

RESULT

In topical dressing A-PRF + HA, there is an increase in delta VEGF on day-3 (43.1 pg/mg protein) and day-7 (275,8 pg/mg protein) compared to A-PRF on day-3 (1.8 pg/mg protein) and day-7 (104.7 pg/mg protein), also NaCl (control) on day-3 (-4.9 pg/mg protein) and day-7 (28.3 pg/mg protein). So that the delta VEGF of A-PRF + HA group increase significantly compared with others on day-3 (p = 0.003) and day- 7 (p < 0.001). Meanwhile A-PRF + AH group, there is also a decrease in delta IL-6 after therapy on day-3 (-10.9 pg/mg protein) and day-7 (-18.3 pg/mg protein) compared to A-PRF in delta IL-6 on day- 3 (-3.7 pg/mg protein) and on day-7 (-7.8 pg/mg protein). In NaCl (control) group there is a increase delta IL-6 on day-3 (4.3 pg/mg protein) and on day-7 (35.5 pg/mg protein). So that the delta IL-6 of A-PRF + HA group decrease significantly compared with others only on day- 7 (p = 0.015). In PDGF le level analysis, A-PRF + HA group increase significantly (p = 0.012) only in day -7 compare with other group (5.5 pg/mg protein).

CONCLUSION

The study shows the superior role of combined A-PRF + HA in the treatment DFU though increase angiogenesis and decrease inflammation pathway. The advantage of using A-PRF + HA is that it accelerates wound healing by increasing granulation tissue compared to A-PRF alone.

Preparation and characterization of poly (lactic-co-glycolic acid) nanofibers containing simvastatin coated with hyaluronic acid for using in periodontal tissue engineering

Periodontal diseases can lead to soft tissue defects. Tissue engineering can provide functional replacements for damaged tissues. Recently, electrospun nanofibers have attracted great interest for tissue engineering and drug delivery applications. This has been revealed that statins exhibit positive impacts on the proliferation and regeneration of periodontal tissues. Electrospun simvastatin loaded poly (lactic-co-glycolic acid) (SIM-PLGA-NF) were prepared using electrospinning technique. Optimal conditions for preparation of SIM-PLGA-NF (PLGA concentration of 30 wt%, voltage of 15 kV, and flow rate of 1.5 ml h^-1 ) were identified using a 2³ factorial design. The optimized SIM-PLGA-NFs (diameter of 640.2 ± 32.5 nm and simvastatin entrapment efficacy of 99.6 ± 1.5%) were surface modified with 1% w/v hyaluronic acid solution (1%HA- SIM-PLGA-NF) to improve their compatibility with fibroblasts and potential application as a periodontal tissue engineering scaffold. HA-SIM-PLGA NFs were analyzed using SEM, FTIR, and XRD. 1%HA-SIM-PLGA-NF had uniform, bead-free and interwoven morphology, which is similar to the extracellular matrix. The mechanical performance of SIM-PLGA-NFs and release profile of simvastatin from these nanofibers have been also greatly improved after coating with HA. In vitro cellular tests showed that the proliferation, adhesion, and differentiation of fibroblast cells positively enhanced on the surface of 1%HA- SIM-PLGA-NF. These results demonstrate the potential application of 1%HA-SIM-PLGA-NFs as a scaffold for periodontal tissue engineering.

Chronic Leg Ulcers: Are Tissue Engineering and Biomaterials Science the Solution?

Chronic leg ulcers (CLUs) are full thickness wounds that usually occur between the ankle and knee, fail to heal after 3 months of standard treatment, or are not entirely healed at 12 months. CLUs present a considerable burden on patients, subjecting them to severe pain and distress, while healthcare systems suffer immense costs and loss of resources. The poor healing outcome of the standard treatment of CLUs generates an urgent clinical need to find effective solutions for these wounds. Tissue Engineering and Biomaterials Science offer exciting prospects for the treatment of CLUs, using a broad range of skin substitutes or scaffolds, and dressings. In this review, we summarize and discuss the various types of scaffolds used clinically in the treatment of CLUs. Their structure and therapeutic effects are described, and for each scaffold type representative examples are discussed, supported by clinical trials. Silver dressings are also reviewed due to their reported benefits in the healing of leg ulcers, as well as recent studies on new dermal scaffolds, reporting on clinical results where available. We conclude by arguing there is a further need for tissue-engineered products specifically designed and bioengineered to treat these wounds and we propose a series of properties that a biomaterial for CLUs should possess, with the intention of focusing efforts on finding an effective treatment.

Use of photosynthetic transgenic cyanobacteria to promote lymphangiogenesis in scaffolds for dermal regeneration

Impaired wound healing represents an unsolved medical need with a high impact on patients´ quality of life and global health care. Even though its causes are diverse, ischemic-hypoxic conditions and exacerbated inflammation are shared pathological features responsible for obstructing tissue restoration. In line with this, it has been suggested that promoting a normoxic pro-regenerative environment and accelerating inflammation resolution, by reinstating the lymphatic fluid transport, could allow the wound healing process to be resumed. Our group was first to demonstrate the functional use of scaffolds seeded with photosynthetic microorganisms to supply tissues with oxygen. Moreover, we previously proposed a photosynthetic gene therapy strategy to create scaffolds that deliver other therapeutic molecules, such as recombinant human growth factors into the wound area. In the present work, we introduce the use of transgenic Synechococcus sp. PCC 7002 cyanobacteria (SynHA), which can produce oxygen and lymphangiogenic hyaluronic acid, in photosynthetic biomaterials. We show that the co-culture of lymphatic endothelial cells with SynHA promotes their survival and proliferation under hypoxic conditions. Also, hyaluronic acid secreted by the cyanobacteria enhanced their lymphangiogenic potential as shown by changes to their gene expression profile, the presence of lymphangiogenic protein markers and their capacity to build lymph vessel tubes. Finally, by seeding SynHA into collagen-based dermal regeneration materials, we developed a viable photosynthetic scaffold that promotes lymphangiogenesis in vitro under hypoxic conditions. The results obtained in this study lay the groundwork for future tissue engineering applications using transgenic cyanobacteria that could become a therapeutic alternative for chronic wound treatment. STATEMENT OF SIGNIFICANCE: In this study, we introduce the use of transgenic Synechococcus sp. PCC 7002 (SynHA) cyanobacteria, which were genetically engineered to produce hyaluronic acid, to create lymphangiogenic photosynthetic scaffolds for dermal regeneration. Our results confirmed that SynHA cyanobacteria maintain their photosynthetic capacity under standard human cell culture conditions and efficiently proliferate when seeded inside fibrin-collagen scaffolds. Moreover, we show that SynHA supported the viability of co-cultured lymphatic endothelial cells (LECs) under hypoxic conditions by providing them with photosynthetic-derived oxygen, while cyanobacteria-derived hyaluronic acid stimulated the lymphangiogenic capacity of LECs. Since tissue hypoxia and impaired lymphatic drainage are two key factors that directly affect wound healing, our results suggest that lymphangiogenic photosynthetic biomaterials could become a treatment option for chronic wound management.

May Autogenous Grafts Increase the Effectiveness of Hyalonect Membranes in Intraosseous Defects: An Experimental In Vivo Study

Background and Objectives: Guided bone regeneration (GBR) surgeries are used for dental implant placements with insufficient bone volume. Biomaterials used in GBR are expected to produce sufficient volume and quality of bone swiftly. This study aims to histologically evaluate the effectiveness of the use of Hyalonect membranes alone or with autogenous grafts in intraosseous defects. Materials and Methods: This study is an experimental study on sheep. Surgeries were performed under general anesthesia in accordance with ethical rules. Five 10 mm defects were surgically created in each ilium of six sheep. One defect was left empty in each ilium (group ED). The defects in the experimental group were covered with Hyalonect membrane while unfilled (group HY) or after being filled with autogenous bone grafts (ABG) (group G+HY). In the control group, the defects were either covered with collagen membrane while unfilled (group CM) or after being filled with the ABG group (G+CM). The sheep were histologically and histomorphometrically evaluated after being postoperatively sacrificed in the third and sixth week (three animals in each interval). Results: All animals completed the study without any complications. No difference was found between groups in the third and sixth weeks regarding the inflammation, necrosis, and fibrosis scores. The G+CM (52.83 ± 3.06) group was observed to have a significantly higher new bone formation rate than all the other groups in the third week, followed by the G+HY group (46.33 ± 2.25). Similar values were found for HY and CM groups (35.67 ± 4.55 ve 40.00 ± 3.41, respectively, p = 0.185), while the lowest values were observed to be in group ED (19.67 ± 2.73). The highest new bone formation was observed in group G+CM (82.33 ± 4.08) in the sixth week. There was no difference in new bone formation rates between groups G+CM, G+HY (77.17 ± 3.49, p = 0.206), and CM (76.50 ± 2.43, p = 0.118). The insignificant difference was found ED group and group HY (55.83 ± 4.92, 73.50 ± 3.27, respectively, p = 0.09). The residual graft amount in the G+CM group was found to be statistically significant at 3 weeks (p = 0.0001), compared to the G+HY group, and insignificantly higher at the 6th week (p = 0.4). Conclusions: In this study, close values were observed between G+HY and G+CM groups. Further experimental and clinical studies with different graft materials are required to evaluate the effectiveness of HY in GBR.

Fabrication of In Situ Layered Hydrogel Scaffold for the Co-delivery of PGDF-BB/Chlorhexidine to Regulate Proinflammatory Cytokines, Growth Factors, and MMP-9 in a Diabetic Skin Defect Albino Rat Model

Diabetes mellitus (DM)-associated impairments in wound healing include prolonged inflammation, the overexpression of matrix metalloproteases (MMPs), and low levels of growth factors at the wound site. To this end, a layer-by-layer scaffold (S_L-B-L) made of cross-linked silk fibroin and hyaluronic acid is developed to deliver chlorhexidine, an antimicrobial agent and an MMP-9 inhibitor, along with the PDGF-BB protein. S_L-B-L exhibited highly porous morphology. Diabetic rats treated with S_L-B-L demonstrated an early wound closure, a fully reconstructed epithelial layer by 14 days, and reduced levels of IL-6, TNF-α, TGF-β1, and MMP-9. Interestingly, S_L-B-L treatment increased angiogenesis, the bioavailability of collagen, DNA content, and VEGF-A levels. Furthermore, enhanced keratinocyte-fibroblast interaction along with ordered collagen deposition was observed in S_L-B-L-treated rats. Most interestingly, when compared with a clinically used scaffold SEESKIN+, S_L-B-L outperformed in promoting wound healing in a diabetic rat model by regulating the inflammation while delivering growth factor and the MMP-9 inhibitor.

Assessment of the Plaque-Induced Gingivitis Patient With and Without Hyaluronic acid and Xylitol Toothpaste

Context:

The traditional manner of treatment of periodontal tissue inflammation includes giving information about the problem to the patient, oral motivation, and mechanical scaling and root planning (SRP).

Aims:

We aimed at estimating the effect of using toothpaste with hyaluronic acid (Hyaluronan, HA) and xylitol (HAX) as a therapeutic agent in the treatment of plaque-induced gingivitis.

Materials and Methods:

Sixty male patients who were in the age group of 20 to 35 years participated in this study. All of them endured 4 appointments, who suffered plaque-induced gingivitis, they distributed into 2 groups depending on the toothpaste variety: group 1 (G1): made up of 30 patients who consume toothpaste that contains HAX, while group 2 (G2): made up of 30 patients who consume toothpaste without HAX (placebo type). Clinical periodontal parameters (CPPs) for all of them were recorded, once at the beginning of the treatment besides four times throughout the treatment at weekly interims during all visits.

Results:

The means of plaque indices (PLI) and gingival indices (GI) decreased along with the sessions for both groups, where the initial means of PLI and GI (baseline) were 2.55 ± 0.14, 2.33 ± 0.15 for the G1, and 2.57 ± 0.13, 2.34 ± 0.16 for G2, respectively; whereas the least means shown at the fourth visit were 0.39 ± 0.05, 0.30 ± 0.06 for G1, and 0.71 ± 0.07, 0.61 ± 0.05 for G2, respectively. There was a reduction in the mean percent of bleeding on probing (BOP) score 1 for all visits in both groups. Finally, an intragroup comparison among dissimilar visits and intergroup comparisons for each visit showed highly significant differences at a P-value of ≤ 0.001 for PLI, GI, and BOP.

Conclusions:

Using toothpaste with or without HAX can decrease gingival inflammation; it can result in a higher improvement in the periodontal status of patients than toothpaste without HAX.

The Role of Extracellular Matrix Components in Inflammatory Bowel Diseases

The remodeling of extracellular matrix (ECM) within the intestine tissues, which simultaneously involves an increased degradation of ECM components and excessive intestinal fibrosis, is a defining trait of the progression of inflammatory bowel diseases (IBDs), which include ulcerative colitis (UC) and Crohn's disease (CD). The increased activity of proteases, especially matrix metalloproteinases (MMPs), leads to excessive degradation of the extracellular matrix and the release of protein and glycoprotein fragments, previously joined with the extracellular matrix, into the circulation. MMPs participate in regulating the functions of the epithelial barrier, the immunological response, and the process of wound healing or intestinal fibrosis. At a later stage of fibrosis during IBD, excessive formation and deposition of the matrix is observed. To assess changes in the extracellular matrix, quantitative measurement of the concentration in the blood of markers dependent on the activity of proteases, involved in the breakdown of extracellular matrix proteins as well as markers indicating the formation of a new ECM, has recently been proposed. This paper describes attempts to use the quantification of ECM components as markers to predict intestinal fibrosis and evaluate the healing process of the gut. The markers which reflect increased ECM degradation, together with the ones which show the process of creating a new matrix during IBD, allow the attainment of important information regarding the changes in the intestinal tissue, epithelial integrity and extracellular matrix remodeling. This paper contains evidence confirming that ECM remodeling is an integral part of directional cell signaling in the progression of IBD, and not only a basis for the ongoing processes.

A halotolerant hyaluronidase from newly isolated Brevibacterium halotolerans DC1: Purification and characterization

An enzyme hyaluronidase (hyase) producing halotolerant bacterium was isolated from dental caries and identified as Brevibacterium halotolerans DC1. Higher growth and hyase production were observed in nutrient broth fortified with hyaluronic acid at pH 7.0, temperature 37 °C, 120 rpm upon 48 h of incubation. Hyase was purified using salt precipitation, DEAE cellulose ion exchange, and Sephadex G-100 gel filtration chromatography. The enzyme was purified to 13-fold with 67.19% recovery of activity and 26.37 U/mg of specific activity. SDS-PAGE and zymography revealed it to be near to homogeneity showing a relative molecular weight of about 43 kDa that was confirmed by MALDI-TOF MS. This hyase was very active and stable at pH 7.0 and temperature 40 °C. The presence of metal ions Ca²⁺ and Mg²⁺ increased its activity while Zn²⁺ and Cu²⁺ severely inhibited it. Being stable at 2 M NaCl, hyase exhibited its halotolerant nature. This enzyme showed wide substrate specificity where hyaluronic acid (HA) was the best substrate. The kinetic studies revealed that K_m and V_max were 91.3 μg/mL and 306.2 μg/mL/min respectively. This is the first report of hyaluronidase from a halotolerant Brevibacterium spp. which can find applications under high salinity.

Evaluation of biochemical and clinical effects of hyaluronic acid on non-surgical periodontal treatment: a randomized controlled trial

BACKGROUND

Recent studies reported that hyaluronic acid (HA) has anti-inflammatory, anti-edematous, and anti-bacterial activities in dentistry, particularly in gingival disorders caused by subgingival plaque microorganisms.

AIMS

This study aimed to evaluate the early term effects of HA as an adjunct to scaling and root planing (SRP) on clinical parameters, periodontal inflamed surface area (PISA), and adenosine deaminase (ADA), catalase (CAT), and glutathione (GSH) levels in gingival crevicular fluid (GCF) in periodontitis.

METHODS

A total of 24 periodontitis patients per group were included in this randomized-controlled study. The study population was divided into four groups: in Group 1: SRP+ saline; in Group 2: SRP + HA gel; in Group 3: SRP+ HA mouth rinse; and in Group 4: SRP + HA mouth rinse + HA gingival gel were applied. At baseline and week 4, clinical parameters and PISA were calculated. Also, biochemicals' (ADA, CAT, and GSH) levels were determined by spectrophotometric analysis.

RESULTS

There was a statistically significant improvement in clinical parameters and PISA in all four groups in control sessions (p < 0.05). There was a significant decrease in ADA in GCF and significant increases in CAT and GSH levels after SRP (p < 0.05) in all four groups. The groups that were administered only gel (2nd and 4th) were different from other groups in terms of ADA, CAT, and GSH levels at 1st week (p < 0.05).

CONCLUSION

HA application as an adjunct to SRP did not affect the clinical results, although, in the control sessions following the application, the results were favorable for the biochemical data in gel-applied groups.

TRIAL REGISTRATION

ClinicalTrials.gov.tr (NCT03754010).

Suppression of hyaluronidase reduces invasion and establishment of Haemonchus contortus larvae in sheep

Haemonchus contortus is a hematophagous endoparasite of small ruminants, which is responsible for huge economic losses in livestock sector. Hyaluronidase produced by infective larvae of H. contortus can degrade hyaluronic acid present in the host’s abomasal tissue. Thus, it facilitates larval tissue invasion and early establishment. We herein explored this ability of hyaluronidase in H. contortus, and tested whether hyaluronidase is utilized as a virulence factor by H. contortus while establishing the infection. We first successfully blocked the hyaluronidase gene in L3 larvae by RNA interference (RNAi), which was subsequently confirmed by qPCR, enzymatic activity, and immunohistochemistry assays. Using these larvae we then conducted in vivo and in vitro assays on sheep to assess the effects of hyaluronidase suppression on larval invasion and establishment of infection. The in vivo assay showed a significant drop in worm burden in siRNA treated group in comparison to control group. During in vitro assay we applied an ovine ex vivo model where siRNA treated group of larvae showed significantly reduced invasion of the abomasal tissue explants as compared to control group. These findings indicate that hyaluronidase plays a key role in host’s tissue invasion and larval establishment, and it is used as a virulence factor by H. contortus while establishing the infection. As an invasive virulence molecule, its functional research is thus conducive to the prevention of haemonchosis.

A polymer-based systemic hemostatic agent

Uncontrolled noncompressible hemorrhage is a major cause of mortality following traumatic injuries in civilian and military populations. An injectable hemostat for point-of-care treatment of noncompressible hemorrhage represents an urgent medical need. Here, we describe an injectable hemostatic agent via polymer peptide interfusion (HAPPI), a hyaluronic acid conjugate with a collagen-binding peptide and a von Willebrand factor-binding peptide. HAPPI exhibited selective binding to activated platelets and promoted their accumulation at the wound site in vitro. In vivo studies in mouse tail vein laceration model demonstrated a reduction of >97% in both bleeding time and blood loss. A 284% improvement in the survival time was observed in the rat inferior vena cava traumatic model. Lyophilized HAPPI could be stably stored at room temperature for several months and reconstituted during therapeutic intervention. HAPPI provides a potentially clinically translatable intravenous hemostat.

Effects of Intraperitoneal Hyaluronan on Peritoneal Fluid and Solute Transport in Peritoneal Dialysis Patients

← Background

Hyaluronan (HA) is a glycosaminoglycan found in connective tissues and tissue spaces, including the peritoneal cavity. In vivo studies in a rat model of peritoneal dialysis (PD) have shown that addition of HA to PD solution during an intraperitoneal dwell can alter peritoneal fluid transport and protect the peritoneal membrane from the effects of inflammation and repeated infusions of dialysis solution. The current study sought to evaluate the safety of intraperitoneal HA and its effect on peritoneal fluid and solute transport when administered during a dialysis dwell in humans.

← Methods

13 PD patients were enrolled in a prospective, randomized crossover study involving three dialysis treatments using the following PD solutions: ( 1 ) a commercially available PD solution (Dianeal PD-4, 1.36% glucose; Baxter Healthcare Corporation, Alliston, Ontario, Canada); ( 2 ) Dianeal PD-4 containing 0.1 g/L HA, and ( 3 ) Dianeal PD-4 containing 0.5 g/LHA. Each 6-hour dialysis exchange was separated from the other exchanges by a 2-week washout period. Radioiodinated human serum albumin (RISA) was administered with the dialysis solution to evaluate intraperitoneal volume, net ultrafiltration (UF), and fluid reabsorption. Peritoneal clearances, dialysate/plasma ratios (D/P), and mass transfer area coefficients (MTACs) were determined for sodium, urea, creatinine, albumin, and glucose. Safety was evaluated by monitoring adverse events and changes in serum chemistries. Ten patients completed all three dialysis exchanges and two additional patients completed at least one treatment exchange.

← Results

There were no reported adverse events related to HA administration and no significant changes in serum chemistries. There were no significant differences in net UF or peritoneal volume profiles among the three treatments. Mean net UF calculated using residual volumes, estimated by RISA dilution, tended to be slightly higher during treatment with solution containing 0.1 g/L HA and 0.5 g/L HA [74 ± 86 (SE) and 41 ± 99 mL, respectively] compared to control treatment (–58 ± 129 mL). Although not statistically significant, there was a trend toward decreased fluid reabsorption during treatment with HA. Solute clearances, D/P ratios, and MTACs were similar for the three treatments. Serum levels of HA were also unaffected by the two treatment solutions.

← Conclusions

These data support the acute safety of HA when administered intraperitoneally with the dialysis solution to PD patients. Due to the small sample size and variability in net UF and fluid reabsorption, statistically significant differences were not demonstrated for these parameters. However, a trend toward decreased fluid reabsorption was observed, suggesting that HA may act by a mechanism similar to that observed in animal studies. Further studies are necessary to evaluate whether the beneficial effects of HA observed in animal studies can be shown in humans.

Role of Peritoneal Mesothelial Cells and Fibroblasts in the Synthesis of Hyaluronan during Peritoneal Dialysis

Objective

To assess the in vitro synthesis rate of hyaluronan (HA) by human peritoneal mesothelial cells and peritoneal fibroblasts in the presence of effluent dialysate from continuous ambulatory peritoneal dialysis (CAPD) patients.

Methods

We used primary cultures of human peritoneal mesothelial cells and peritoneal fibroblasts from nonuremic patients to study the effect of interleukin-1 β (11–1 β) and pooled effluent dialysate, from noninfected and infected CAPD patients, on the synthesis of HA by the studied cells. We also tested the effect of the exogenous HA on the synthesis rate of that glycosaminoglycan. We studied the correlation between HA concentration in effluent dialysate and the stimulatory effect of that solution on in vitro synthesis of HA by mesothelium.

Results

Peritoneal fibroblasts produce more HA than mesothelial cells. Noninfected effluent dialysates or dialysates from CAPD patients with peritonitis stimulate synthesis of HA by mesothelial cells and fibroblasts. Interleukin-1 β has a stimulating effect, which was synergistic with effluent dialysates, on the synthesis of HA by mesothelium and peritoneal fibroblasts. A weak correlation was demonstrated between the level of HA in effluent dialysate and the stimulatory effect of that dialysate on in vitro synthesis of HA by mesothelial cells.

Conclusions

Peritoneal fibroblasts are a more potent source of HA than are mesothelial cells, but probably the latter are the main source of HA in drained dialysate. Although effluent dialysates contain factors that stimulate the production of HA by mesothelium, there is weak correlation between that stimulatory effect and the actual HA concentration in the dialysate, which, in some patients, might suggest low “responsiveness” of the membrane.

Synthesis of Hyaluronic Acid by Human Peritoneal Mesothelial Cells: Effect of Cytokines and Dialysa Te

Objective

To assess effects of the inflammatory cytokines (IL-1-beta, TNF-alpha, TGF-beta 1) and dialysate effluent on synthesis of hyaluronic acid by human peritoneal mesothelial cells (HMC) in in vitro culture.

Methods

Dialysate effluent was collected after the overnight dwell of DianeaI 1.5% from patients during CAPD training. HMC were obtained from omentum from nonuremic donors or were harvested from the dialysate effluent from CAPD patients. Synthesis of hyaluronic acid was studied on monolayers of HMC, which were deprived of serum 48 hours priortoexperiment. Effects of cytokines were tested in a medium with low serum concentration (0.1%) or in medium mixed (1:1 v/v) with the autologous dialysate. Hyaluronic acid level in medium was measured with radioimmunoassay.

Results

Cytokines enhanced synthesis of hyaluronic acid by HMC, and the strongest effect was induced by IL-1. Effluent dialysate stimulates synthesis of hyaluronic acid stronger than 10% FCS. Effluent dialysate and IL-1 synergistically enhance synthesis of hyaluronic acid by HMC.

Conclusion

Effluent dialysate from CAPD patients stimulates production of hyaluronic acid by HMC and acts synergistically with cytokines.

N-Acetylglucosamine Changes Permeability of Peritoneum during Chronic Peritoneal Dialysis in Rats

Objective

To evaluate the effect of supplementation of dialysis fluid with N-acetylglucosamine (NAG) on the permeability of peritoneum during chronic peritoneal dialysis in rats.

Design

Experiments were performed on rats with surgically implanted peritoneal catheters. Dialysis solution [DianeaI1.5% (Baxter, Deerfield, IL, U.S.A.) supplemented with either NAG 50 mmol/L or glucose 50 mmol/L (control)] was infused intraperitoneally twice, every day, for 8 weeks. Peritoneal equilibration tests (PET) were performed in all animals at the beginning of the study and after 8 weeks of dialysis. Additionally, at the end of each week, dialysis solution infused in the morning was drained after 4 hours of intraperitoneal dwell. White blood cell count, creatinine, and total protein concentrations were measured in the effluent dialysate. After 8 weeks of dialysis, the morphology of the peritoneum was studied.

Results

In rats exposed to dialysis fluid supplemented with NAG, peritoneal permeability to creatinine and proteins was reduced when compared to animals dialyzed with glucose solution. In NAG treated animals, staining with alcian blue for polyanions in the peritoneal interstitium was significantly stronger than in rats dialyzed with glucose solution.

Conclusions

Chronic peritoneal dialysis with dialysis solution supplemented with N-acetylglucosamine causes accumulation of glycosaminoglycans in the peritoneal interstitium, which results in a change of peritoneal permeability.

Intraperitoneal Hyaluronan Production in Stable Continuous Ambulatory Peritoneal Dialysis Patients

Objective

Several cytokines and proteins are excreted intraperitoneally during the course of peritonitis and stable states in continuous ambulatory peritoneal dialysis (CAPD) patients. Dialysate hyaluronan (HYA) is also regarded as a marker of peritoneal healing during bacterial peritonitis. We examined here, intraperitoneal HYA production in stable CAPD patients and compared the results to those of the peritoneal equilibration test (PET), the length of time on dialysis, and other marker proteins.

Design

We determined the concentration of HYA and other marker proteins in the 4-hour-dwell dialysate at 1-year intervals.

Setting

CAPD unit in Hitachi General Hospital.

Patients

The subjects were 46 stable CAPD patients who underwent 104 PETs.

Results

A correlation was found between the length of time on dialysis and the amount of HYA excretion in the 4-hr-dwell dialysate ( r = 0.403, p < 0.001). A positive but weak correlation was found between the dialysate-to-plasma ratio of the creatinine concentration and dialysate HYA excretion ( r = 0.229, p < 0.05). Seven patients were over the 90th percentile in both the concentration of HYA (>349.2 ng/mL) and the amount of HYA (>743.6 μg/4-hr dwell). Five patients exceeded 1000 μg of HYA excretion in the 4-hr-dwell dialysate, 4 of whom showed an abrupt increase of HYA excretion to more than 1000 μg/4-hr dwell, and discontinued CAPD within 6 months due to ultrafiltration failure. Two of these 4 patients were diagnosed with sclerosing encapsulating peritonitis at autopsy.

Conclusion

Intraperitoneal HYA production increased with both higher permeable membrane and the length of time on CAPD. Monitoring of HYA in the peritoneal dialysate may be useful as a marker to assess functional and morphological changes in the peritoneum in long-term CAPD patients.

Poly(ε-Caprolactone) Nanofiber Wrap Improves Nerve Regeneration and Functional Outcomes after Delayed Nerve Repair

BACKGROUND

The purpose of this study was to assess the efficacy of biodegradable, electrospun poly(ε-caprolactone) nanofiber nerve conduits in improving nerve regeneration.

METHODS

The authors used a rat forelimb chronic denervation model to assess the effects of poly(ε-caprolactone) conduits on improving nerve regeneration and upper extremity function. Three groups of rats were examined: (1) negative-control animals (n = 5), which underwent 8 weeks of median nerve chronic denervation injury followed by repair with no conduit; (2) experimental animals (n = 5), which underwent 8 weeks of median nerve chronic denervation followed by repair and poly(ε-caprolactone) nerve conduit wrapping of the nerve coaptation site; and (3) positive-control animals (n = 5), which were naive controls. All animals underwent compound muscle action potential and functional testing. At 14 weeks after repair, the median nerve and flexor muscles were harvested for histologic analysis.

RESULTS

Histomorphometric analysis of regenerating median nerves demonstrated augmented axonal regeneration in experimental versus negative control animals (total axon count, 1769 ± 672 versus 1072 ± 123.80; p = 0.0468). With regard to functional recovery, experimental and negative-control animals (1.67 ± 0.04 versus 0.97 ± 0.39; p = 0.036) had regained 34.9 percent and 25.4 percent, respectively, of baseline hand grip strength at 14 weeks after repair. Lastly, less collagen deposition at the nerve coaptation site of experimental animals was found when compared to control animals (p < 0.05).

CONCLUSION

Biodegradable, poly(ε-caprolactone) nanofiber nerve conduits can improve nerve regeneration and subsequent physiologic extremity function in the setting of delayed nerve repair by decreasing the scar burden at nerve coaptation sites.

Short-term effects of hyaluronic acid on the subgingival microbiome in peri-implantitis: A randomized controlled clinical trial

BACKGROUND

The aim of our study was to evaluate the effects of a hyaluronic acid (HA) gel at 45 days on the microbiome of implants with peri-implantitis with at least 1 year of loading.

METHODS

A randomized controlled trial was conducted in peri-implantitis patients. Swabs containing the samples were collected both at baseline and after 45 days of treatment. 16S rRNA sequencing techniques were used to investigate the effect of HA gel on the subgingival microbiome.

RESULTS

One hundred and eight samples of 54 patients were analyzed at baseline and after follow-up at 45 days. Three strata with different microbial composition were obtained in the samples at baseline, representing three main microbial consortia associated with peri-implantitis. Stratum 1 did not show any difference for any variable after treatment with HA, whereas in stratum 2, Streptococcus, Veillonella, Rothia, and Granulicatella did decrease (P < 0.05). Similarly, Prevotella and Campylobacter (P < 0.05) decreased in stratum 3 after treatment with HA. Microbial diversity was found to be decreased in stratum 3 (P < 0.05) after treatment with HA compared with the control group, in which an increase was found (P < 0.05).

CONCLUSIONS

HA reduced the relative abundance of peri-implantitis-related microorganisms, especially the early colonizing bacteria, suggesting a specific action during the first stages in the development of the disease. HA did not alter relative abundances of non-oral genera. The use of HA in advanced stages of peri-implantitis resulted in a decrease in microbial alpha diversity, suggesting a protective action of the peri-implant site against bacteria colonization.

Plasma High Mobility Group Box 1 (HMGB1), Osteopontin (OPN), and Hyaluronic Acid (HA) as Admissible Biomarkers for Endometriosis

Identification of biomarkers for endometriosis is an unmet medical need that demands to be fulfilled. In this study, we first used a mouse model of endometriosis and evaluated the potential utility of select biomarkers based on serial observations. Since fibrosis is the end result of lesional development, we chose high mobility group box 1 (HMGB1), osteopontin (OPN), and hyaluronic acid (HA), all three of them have been well documented to be involved in endometriosis and fibrosis, as potential biomarkers. In addition, we performed immunohistochemistry analysis of HMGB1, OPN, and the receptors for HMGB1, such as toll-like receptor 4 (TLR4), nuclear factor κB (NF-κB), proliferating cell nuclear antigen (PCNA), interleukin-33 (IL-33), and receptor for advanced glycation endproducts (RAGE)–a pattern recognition receptor, with HMGB1 being its important ligand. We then evaluated the same set of putative markers in 30 women with ovarian endometriomas and 20 without endometriosis, and reevaluated the 3 plasma markers 3 months after the surgical removal of all visible endometriotic lesions. In mouse, the lesional staining levels of OPN, RAGE, and IL-33 were all significantly higher than that of normal endometrium, and increased progressively as lesions progressed. In contrast to HMGB1, TLR4, p-p65 and PCNA staining levels were decreased progressively. In humans, lesional staining levels of OPN correlated positively, while that of HMGB1 correlated negatively with the extent of fibrosis. All three plasma markers correlated positively with the extent of lesional fibrosis. Through this integrated approach, we identified plasma HMGB1, OPN and HA as promising admissible biomarkers for endometriosis.

Hyaluronic Acid: Molecular Mechanisms and Therapeutic Trajectory

Hyaluronic acid (also known as hyaluronan or hyaluronate) is naturally found in many tissues and fluids, but more abundantly in articular cartilage and synovial fluid (SF). Hyaluronic acid (HA) content varies widely in different joints and species. HA is a non-sulfated, naturally occurring non-protein glycosaminoglycan (GAG), with distinct physico-chemical properties, produced by synoviocytes, fibroblasts, and chondrocytes. HA has an important role in the biomechanics of normal SF, where it is partially responsible for lubrication and viscoelasticity of the SF. The concentration of HA and its molecular weight (MW) decline as osteoarthritis (OA) progresses with aging. For that reason, HA has been used for more than four decades in the treatment of OA in dogs, horses and humans. HA produces anti-arthritic effects via multiple mechanisms involving receptors, enzymes and other metabolic pathways. HA is also used in the treatment of ophthalmic, dermal, burns, wound repair, and other health conditions. The MW of HA appears to play a critical role in the formulation of the products used in the treatment of diseases. This review provides a mechanism-based rationale for the use of HA in some disease conditions with special reference to OA.

Hyaluronan in inflammatory bowel disease: Cross-linking inflammation and coagulation

Hyaluronan, a major extracellular matrix component, is an active participant in many disease states, including inflammatory bowel disease (IBD). The synthesis of this dynamic polymer is increased at sites of inflammation. Hyaluronan together with the enzymes responsible for its synthesis, degradation, and its binding proteins, directly modulates the promotion and resolution of disease by controlling recruitment of immune cells, by release of inflammatory cytokines, and by balancing hemostasis. This review discusses the functional significance of hyaluronan in the cells and tissues involved in inflammatory bowel disease pathobiology.

Application of hyaluronic acid/carboxymethyl cellulose membrane for early continence after nerve-sparing robot-assisted radical prostatectomy

Background

To assess whether application of a hyaluronic acid-carboxymethyl cellulose membrane (HA/CMC) to the prostate bed and neurovascular plate facilitated early return of continence after nerve-sparing robot-assisted radical prostatectomy (RARP).

Methods

The subjects were 183 consecutive patients with organ-confined prostate cancer who underwent unilateral or bilateral nerve-sparing RARP. After vesicourethral anastomosis, HA/CMC was placed to cover Denonvilliers’ fascia (behind the anastomotic suture) and the preserved neurovascular plate. The time until complete continence after RARP and perioperative complications were compared between patients with or without HA/CMC.

Results

HA/CMC was applied in 13/46 patients (28.3%) receiving bilateral nerve-sparing surgery and 40/137 patients (29.2%) receiving unilateral nerve-sparing surgery. After bilateral nerve-sparing RARP, the median time until continence was significantly shorter in patients with HA/CMC than in those without HA/CMC (3.2 vs. 9.3 months, respectively, p < 0.01). After unilateral nerve-sparing RARP, the median time until continence was also significantly shorter in patients with HA/CMC than in those without HA/CMC (3.2 vs. 12.0 months, respectively, p < 0.01). Multivariate Cox proportional hazards regression analysis showed that an age < 70 years (hazard ratio [HR]: 1.74, 95% confidence interval [CI]: 1.12–2.80), institutional caseload > 200, (HR: 1.64, 95%CI: 1.10–2.47), and use of HA/CMC (HR: 1.84, 95%CI: 1.22–2.76) were independent predictors of early postoperative continence. Complication rates, including urinary leakage, did not differ significantly between patients with or without HA/CMC.

Conclusion

Application of HA/CMC to the prostate bed and neurovascular plate resulted in significantly faster postoperative return of continence after both unilateral and bilateral nerve-sparing RARP.

Evaluation of the effectiveness of kINPen Med plasma jet and bioactive agent therapy in a rat model of wound healing

Chronic nonhealing wounds, particularly those complicated by multidrug resistant infections, represent a major health and economic challenge. Plasma treatment promotes wound repair due to its antimicrobial, angiogenic, and cell modulating properties. This study investigated the efficacy of the kINPen Med system in promoting healing and assessed if efficacy was enhanced by adding collagen or hyaluronic acid (HA). Two 6 mm diameter punch biopsy wounds were created on the lumbar spine of Sprague Dawley rats. Based on the results of a pilot study, operating process conditions involving 30 s plasma/day were selected for the pivotal study. In the pivotal study, six groups of rats (n = 28/group) received either control (1), plasma (2), HA (3), plasma and HA (4), collagen (5), or plasma and collagen (6). Wound measurements were obtained on Days 0, 4, 7, and 14. The mean reduction in wound size was significantly higher in all treatment groups compared to controls on Day 4; group 6 performed best. On Day 7, group 6 still performed significantly better compared to groups 1, 2, 3, and 4. Day 14 results were more comparable between groups. Histology (Day 14) revealed epidermal hyperplasia and serocellular crusts. Neutrophilic infiltrates in group 6 were significantly lower compared to group 2. Mononuclear infiltrates were highest in groups 3 and 5, while Langerhans cells were observed in all groups. These results underpin the clinical benefits of the kINPen Med plasma system, particularly when combined with collagen during early inflammatory phases, and support the conduct of future human clinical trials.

BDNF/HMW-HA complex as an adjunct to nonsurgical periodontal treatment of ligature-induced periodontitis in dogs

BACKGROUND

Recently, brain-derived neurotrophic factor (BDNF)/high molecular weight hyaluronic acid (HMW-HA) complex with flap surgery has been shown to promote periodontal tissue regeneration. The objective of this study was to evaluate the effects of local subgingival application of BDNF/HMW-HA complex adjunctive to scaling and root planning (SRP) on ligature-induced periodontitis in dogs.

METHODS

The dogs were divided into four treatment groups: no treatment (control), SRP alone, SRP followed by local application of HMW-HA (SRP+HMW-HA), and SRP followed by local application of BDNF (500 μg/ml)/ HMW-HA complex (SRP+BDNF/HMW-HA). HMW-HA or BDNF/HMW-HA complex was topically applied to periodontal pockets using a syringe without surgery. Two weeks after treatment, clinical parameters (gingival index, clinical attachment level, periodontal pocket depth and bleeding on probing) were recorded and specimens were collected from anesthetized animals for histological analysis.

RESULTS

The SRP+BDNF/HMW-HA group showed significant improvement in all clinical parameters compared to other treatment groups. Histologic analysis showed greater suppression of apical migration of epithelial tissue and milder inflammatory cell infiltration in the SRP+BDNF/HMW-HA group than in the other treatment groups. Furthermore, new cementum and alveolar bone were regenerated, and collagen fibers were inserted into them in the SRP+BDNF/HMW-HA group.

CONCLUSION

BDNF/HMW-HA complex as an adjunct to nonsurgical periodontal treatment has the potential to reduce excess inflammation. Further investigation will be needed to clarify periodontal tissue regenerative effects of BDNF/HMW-HA complex in a nonsurgical setting.

The Effect of a Dissolvable Hyaluronic Acid–Based Pack on the Healing of the Nasal Mucosa of Sheep

Introduction

There is a paucity of knowledge about the healing of the nasal respiratory mucosa after endoscopic sinus surgery (ESS). Nasal packs often are placed after ESS in an attempt to reduce adhesions but the effect of these packs on the healing of the nasal mucosa is not known.

Methods

A standardized normal animal model (the sheep) was used to examine the healing of the nasal epithelium after ESS. A full-thickness wound was created in the nasal mucosa and either packed with a dissolvable hyaluronic acid–based pack or left unpacked to serve as control. The wounded areas were biopsied at 28, 56, 84, and 112 days postinjury and epithelialization, and cilial regeneration was assessed by light microscopy and scanning electron microscopy.

Results

The wounds with the dissolvable hyaluronic acid–based packs showed no differences in reepithelialization up to 84 days postwounding. However, a significant increase in reepithelialization was observed on day 84 in packed wounds compared with unpacked controls, indicating an increased rate of healing at that time point. In addition, there was a significant increase in the epithelial height in the packed wounds on day 28, indicating that packing was affecting the epithelial maturity of the mucosa. No significant difference was observed in cilial regeneration between the packed and control wounds.

Conclusions

Application of the hyaluronic acid–based nasal packs to wounds after ESS may improve reepithelialization of the nasal mucosa but appears to have minimal effect on reciliation at the time points studied in normal-healing wounds.

Effect of a new cross-linked hyaluronan gel on the staple line after sleeve gastrectomy in a rat model

PURPOSE

To evaluate the effect of a new cross-linked hyaluronan (NCHA) gel on healing of the staple line in an experimental sleeve gastrectomy.

METHODS

Eighteen rats were randomly divided into three groups. The control group (n = 6) received no medication. In the saline group (n = 6) and NCHA gel group (n = 6), saline and NCHA gel were respectively administered onto the staple line and intraperitoneally into the abdominal cavity after the standard stapling procedure.

RESULTS

The fibroblast activity and collagen deposition were significantly higher in the NCHA gel group than in the control group (p = 0.00, p = 0.017) and saline group (p = 0.004, p = 0.015). The tissue hydroxyproline protein level was significantly higher in the NCHA gel group than in the control group (p = 0.041). Adhesion formation was significantly lower in the NCHA gel group than in the control and saline groups (p = 0.015, p = 0.041).

CONCLUSIONS

New cross-linked hyaluronan gel could be an effective approach to improve staple line wound healing and prevent potential leakage after sleeve gastrectomy. Moreover, NCHA gel helps to prevent adhesion formation without compromising healing of the staple line.

Biomaterials for Skin Substitutes

Patients with extensive burns rely on the use of tissue engineered skin due to a lack of sufficient donor tissue, but it is a challenge to identify reliable and economical scaffold materials and donor cell sources for the generation of a functional skin substitute. The current review attempts to evaluate the performance of the wide range of biomaterials available for generating skin substitutes, including both natural biopolymers and synthetic polymers, in terms of tissue response and potential for use in the operating room. Natural biopolymers display an improved cell response, while synthetic polymers provide better control over chemical composition and mechanical properties. It is suggested that not one material meets all the requirements for a skin substitute. Rather, a composite scaffold fabricated from both natural and synthetic biomaterials may allow for the generation of skin substitutes that meet all clinical requirements including a tailored wound size and type, the degree of burn, the patient age, and the available preparation technique. This review aims to be a valuable directory for researchers in the field to find the optimal material or combination of materials based on their specific application.