In-stent restenosis is associated with proliferative skin healing and specific immune and endothelial cell profiles: results from the RACHEL trial.

Introduction: In-stent restenosis (ISR) is a major challenge in interventional cardiology. Both ISR and excessive skin healing are aberrant hyperplasic responses, which may be functionally related. However, the cellular component underlying ISR remains unclear, especially regarding vascular homeostasis. Recent evidence suggest that novel immune cell populations may be involved in vascular repair and damage, but their role in ISR has not been explored. The aims of this study is to analyze (i) the association between ISR and skin healing outcomes, and (ii) the alterations in vascular homeostasis mediators in ISR in univariate and integrative analyses. Methods: 30 patients with ≥1 previous stent implantation with restenosis and 30 patients with ≥1 stent without restenosis both confirmed in a second angiogram were recruited. Cellular mediators were quantified in peripheral blood by flow cytometry. Skin healing outcomes were analyzed after two consecutive biopsies. Results: Hypertrophic skin healing was more frequent in ISR patients (36.7%) compared to those ISR-free (16.7%). Patients with ISR were more likely to develop hypertrophic skin healing patterns (OR 4.334 [95% CI 1.044-18.073], p=0.033), even after correcting for confounders. ISR was associated with decreased circulating angiogenic T-cells (p=0.005) and endothelial progenitor cells (p<0.001), whereas CD4+CD28null and detached endothelial cells counts were higher (p<0.0001 and p=0.006, respectively) compared to their ISR-free counterparts. No differences in the frequency of monocyte subsets were found, although Angiotensin-Converting Enzyme expression was increased (non-classical: p<0.001; and intermediate: p<0.0001) in ISR. Despite no differences were noted in Low-Density Granulocytes, a relative increase in the CD16- compartment was observed in ISR (p=0.004). An unsupervised cluster analysis revealed the presence of three profiles with different clinical severity, unrelated to stent types or traditional risk factors. Conclusion: ISR is linked to excessive skin healing and profound alterations in cellular populations related to vascular repair and endothelial damage. Distinct cellular profiles can be distinguished within ISR, suggesting that different alterations may uncover different ISR clinical phenotypes.

Improved Tool for Predicting Skin Irritation on Reconstructed Human Epidermis Models Based on Electrochemical Impedance Spectroscopy.

The rabbit skin irritation test has been the standard for evaluating the irritation potential of chemicals; however, alternative methods that do not use animal testing are actively encouraged. Reconstructed human epidermis (RhE) models mimic the biochemical and physiological properties of the human epidermis and can be used as an alternative method. On RhE methods, the metabolic activity of RhE models is used to predict skin irritation, with a reduction in metabolic activity indicating a reduced number of viable cells and linking cell death to skin irritation processes. However, new challenges have emerged as the use of RhE models increases, including the need for non-invasive and marker-free methodologies to assess cellular states. Electrochemical impedance spectroscopy (EIS) is one such methodology that can meet these requirements. In this study, our results showed that EIS can differentiate between irritant and non-irritant chemicals, with a significant increase in the capacitance values observed in the irritant samples. A ROC curve analysis showed that the prediction method based on EIS met OECD TG 439 requirements at all time points and had 95% within-laboratory reproducibility. Comparison with the MTT viability assay showed that prediction using EIS achieved higher sensitivity, specificity, and accuracy. These results suggest that EIS could potentially replace animal testing in the evaluation of irritation potential and could be a valuable addition to in vitro testing strategies.

A Simple, Safe, and Effective Method for Preparing Autologous Bio-Based Fibrin Glue for Ophthalmic Use.

This study proposes a method to prepare autologous bio-based fibrin glue (FG) for use in ophthalmic surgery. FGs containing three fibrinogen concentrations and a thrombin concentrate were prepared using human blood from five donors (FG1: physiological fibrinogen concentration; FG2 and FG3: concentrated fibrinogen). The adhesion strength was tested, and the clinical safety and efficacy were studied in rabbit eyes in conjunctival surgery. A commercial FG was used as a control. From each donor, 2 mL of FG was prepared, containing 1 mL of 3.49 ± 0.78 (FG1), 17.74 ± 4.66 (FG2), or 47.46 ± 9.36 mg/mL (FG3) of fibrinogen and 1 mL of 2248.12 ± 604.20 UI/mL of thrombin. The average adhesion strength increased with the fibrinogen concentration, from 1.49 ± 0.39 kPa (FG1) to 3.14 ± 1.09 kPa (FG3). FG1 showed poor results when used for autograft adhesion. In contrast, the conjunctival autografts were successfully grafted using FG2 and FG3, revealing equivalent adhesion properties compared with commercial FG, but with less inflammation. In conclusion, FGs could be prepared on demand within minutes from small volumes of human blood, using a method that results in FGs which exhibit good adhesion capacity and are also safe and effective in a preclinical study.

Polymerizable Skin Hydrogel for Full Thickness Wound Healing.

The skin is the largest organ in the human body, comprising the main barrier against the environment. When the skin loses its integrity, it is critical to replace it to prevent water loss and the proliferation of opportunistic infections. For more than 40 years, tissue-engineered skin grafts have been based on the in vitro culture of keratinocytes over different scaffolds, requiring between 3 to 4 weeks of tissue culture before being used clinically. In this study, we describe the development of a polymerizable skin hydrogel consisting of keratinocytes and fibroblast entrapped within a fibrin scaffold. We histologically characterized the construct and evaluated its use on an in vivo wound healing model of skin damage. Our results indicate that the proposed methodology can be used to effectively regenerate skin wounds, avoiding the secondary in vitro culture steps and thus, shortening the time needed until transplantation in comparison with other bilayer skin models. This is achievable due to the instant polymerization of the keratinocytes and fibroblast combination that allows a direct application on the wound. We suggest that the polymerizable skin hydrogel is an inexpensive, easy and rapid treatment that could be transferred into clinical practice in order to improve the treatment of skin wounds.

In-house performance assessment of 3D QobuR-Reconstructed Human Cornea-Like Epithelium (RhCE) for the evaluation of eye hazard.

To replace the Draize eye irritation test (OECD Test Guideline 404), several test methods based on reconstructed cornea-like epithelium (RhCE) have been developed and adopted in the OECD TG 492. The objective of this study was to stablish the experimental procedures and evaluate the performance assessment of QobuR-RhCE, an in-house RhCE model to be used for the evaluation of eye hazard. We define the essential structural, functional and procedural elements of the test method components to help assuring that the proposed test method is based on the same concepts as the validated reference methods. Performance assessment was evaluated in accordance with the revised performance standards for the assessment of proposed similar or modified in vitro reconstructed human cornea-like epithelium and the minimum list of reference chemicals was evaluated. As result, the proposed method scored 93.3% sensibility, 60% specificity, 76.7% accuracy and 96.7% within-laboratory reproducibility (WLR), providing a similar performance in comparison to the validated reference methods. Additionally, we describe a secondary endpoint based on Transepithelial Electrical Resistance (TEER) that could be of use to better discriminate between irritants and non-irritants. Taken together the results indicate that the QobuR-RhCE test method is an accurate screening tool that can be used as a standalone alternative to evaluate ocular irritation.

Impedance-based non-invasive assay for ocular damage prediction on in vitro 3D reconstructed human corneal epithelium.

Reconstructed human cornea-like epithelium (RhCE) holds unprecedented promise for toxicological analyses and the replacement of animal use. However, current standards to evaluate potential ocular irritancy present a major downfall, the need to invasively alter tissue samples to evaluate cell viability. In this study, the applicability of impedance analysis was validated by monitoring the change in cell capacitance during tissue maturation and before and after chemical application using coupled electrodes. Our results indicate that cell maturation on RhCE models can be evaluated during model production using capacitance sensing offering a faster and simpler quality control criteria for RhCE model usability. Additionally, cell capacitance resulted to be more sensitive in detecting slight cell damages than methods based on cell metabolism, and when integrated into OECD-approved testing strategies, capacitance sensing performed as good as currently accepted methodologies displaying 66% sensitivity, 100% specificity and 83% accuracy when evaluated at 300 Hz. In summary, a quantitative analysis to predict in vivo ocular irritation based on changes in RhCE capacitance by impedance spectroscopy is suggested. This methodology represents a non-invasive and non-destructive alternative that would enable the monitoring of reversible effects or repeated dose toxicity.

Eye bank versus surgeon prepared DMEK tissues: influence on adhesion and re-bubbling rate.

AIM: To investigate the difference in adhesion and rebubbling rate between eye bank and surgeon prepared Descemet membrane endothelial keratoplasty (DMEK) tissues. METHODS: Laboratory and clinical retrospective comparative interventional case series. Research corneal tissues were obtained for laboratory investigation. The clinical study involved patients with endothelial dysfunction who underwent DMEK surgery and tamponade with air. Tissues were stripped using a standard DMEK stripping technique (SCUBA) and shipped as prestripped or loaded in a 2.2 intra-ocular lens cartridge with endothelium facing inwards (preloaded) before transporting from the eye bank to the surgeon. For surgeon prepared tissues, all the grafts were stripped in the theatre and transplanted or stripped in the laboratory and tested immediately. Adhesion force and elastic modulus were measured in the centre and mid-periphery in a laboratory ex vivo investigation using atomic force microscopy, while rebubbling rates were recorded in the clinical study. RESULTS: There was no difference in endothelial cell viability between surgeon or eye bank prepared tissue. Surgeon-stripped DMEK grafts in the laboratory investigation showed significantly higher elastic modulus and adhesion force compared to prestripped and preloaded tissues (p<0.0001). In the clinical data, rebubbling rates of 48%, 40% and 15% were observed in preloaded, prestripped and surgeon-stripped DMEK grafts, respectively. Rebubbling rates were significantly associated with combined cataract surgery (p=0.009) and with time from harvesting the graft to the surgery (p=0.02). CONCLUSIONS: Decreased adhesion forces and elastic modulus in eye bank prepared tissues may contribute to increased rebubbling rates.

Novel technique of development of human derived acellular dermal matrix.

Reconstructive surgery techniques have evolved exponentially in last decades. From regional flaps to free tissue transfer, tissue movilization has become the gold standart treatment in many reconstructive procedures. Main disadvantage from these techniques lies in the possibility of sequels in donor zone. Furthermore, raising comorbidities in general population and growing indications for reconstructive surgery in elder people, have triggered the development of new biomaterials which can offer support in the reconstruction while elicit donor zone morbidity. Advances in tissue decellularization techniques have brought numerous matrices which have shown effectivity in many reconstructive procedures. Use of acellular dermal matrices may become an eligible solution for many reconstructive procedures. From breast reconstruction assisted by matrices to complex wound coverage passing throught tendon repair techniques, acellular dermal matrices have shown effectiveness in last studies. Local production of this biomaterial leads to cost minimization derived from harvesting and manufacturing matrices in our centre and avoid out-of-stock and storage issues. Current original protocol proposed by our group include all steps from harvesting samples from cadaveric donors till matrix storage after decellularization proccess. The result is a high valued biomaterial in terms of biocompatibility and security profile available.

The TNF-α (-238 G/A) polymorphism could protect against development of severe sepsis.

Primary responses in sepsis-mediated inflammation are regulated by pro-inflammatory cytokines. Variations in the cytokine genes might modify their transcription or expression, plasma cytokines levels and response to sepsis. Activation protein-1 (AP-1) and NF-κB regulate cytokines gene expression in sepsis. A total of 90 severely septic and 91 non-infected patients were prospectively studied. IL-1α (-889 C/T), IL-1ß (+3954 C/T), IL-6 (-174 G/C), TNF-α (-238 G/A), TNF-α (-308G/A), IL-8 (-251A/T) and IL-10 (-1082 G/A) SNPs, plasma IL-1ß, IL-4, IL-6, IL-8, IL-10, IL-13, IFN-γ, TNF-α and monocyte chemoattractant protein 1 (MCP-1) levels, and AP-1 and NF-κB gene expression by neutrophils were assessed. A allele carriers of TNF-α (-238 G/A) SNP were less frequent among septic patients. IL-6, IL-8, IL-10, TNF-α and MCP-1 levels were higher, and AP-1 and NF-κB gene expressions lower in septic patients. Sepsis was independently associated with higher fibrinogen, neutrophils counts and IL-8 levels, lower prothrombin, absence of the variant A allele of the TNF-α (-238 G/A) SNP, and haemodynamic failure. Death was independently associated with a higher APACHE II score, higher IL-8 levels, and the diagnosis of sepsis. TNF-a (-238 G/A) SNP could protect against sepsis development. Higher IL-8 levels are predictive of sepsis and mortality.

Mini Cleanroom for the Manufacture of Advanced Therapy Medicinal Products (ATMP): Bioengineered Corneal Epithelium.

Among several requirements for the manufacture of Advanced Therapy Medicinal Products (ATMP) are: following the guidelines of a pharmaceutical quality system, complying with Good Manufacturing Practice (GMP) and access to a cleanroom fulfilling strict environmental conditions (Class A work area and Class B environment). This makes ATMP expensive. Moreover, the production of many of these therapeutic products may also be unprofitable, as in most cases their use is limited to a few patients and to a single batch per manufacturing unit. To reduce costs, ATMP may be produced in a scaled-down system isolated from the external environment (isolator), allowing for placement of this facility in a Class D environment, which is much more permissive and less costly. In this work, we confirm that it is possible to manufacture bioengineered corneal epithelium inside an isolator while fulfilling all the safety assurance standards at an affordable cost for patients. This small-scale ultra-clean working environment complies with GMP guidelines and could be a solution for the high costs associated with conventional cleanroom ATMP production.

Fibrin-Plasma Rich in Growth Factors Membrane for the Treatment of a Rabbit Alkali-Burn Lesion.

The purpose of this work is to describe the use of Fibrin-Plasma Rich in Growth Factors (PRGF) membranes for the treatment of a rabbit alkali-burn lesion. For this purpose, an alkali-burn lesion was induced in 15 rabbits. A week later, clinical events were evaluated and rabbits were divided into five treatment groups: rabbits treated with medical treatment, with a fibrin-PRGF membrane cultured with autologous or heterologous rabbit Limbal Epithelial Progenitor Cells (LEPCs), with a fibrin-PRGF membrane in a Simple Limbal Epithelial Transplantation and with a fibrin-PRGF membrane without cultured LEPCs. After 40 days of follow-up, corneas were subjected to histochemical examination and immunostaining against corneal or conjunctival markers. Seven days after alkali-burn lesion, it was observed that rabbits showed opaque cornea, new blood vessels across the limbus penetrating the cornea and epithelial defects. At the end of the follow-up period, an improvement of the clinical parameters analyzed was observed in transplanted rabbits. However, only rabbits transplanted with cultured LEPCs were positive for corneal markers. Otherwise, rabbits in the other three groups showed positive staining against conjunctival markers. In conclusion, fibrin-PRGF membrane improved the chemically induced lesions. Nonetheless, only fibrin-PRGF membranes cultured with rabbit LEPCs were able to restore the corneal surface.

Comparative analysis of plasma-derived albumin scaffold, alveolar osteoblasts and synthetic membrane in critical mandibular bone defects: An experimental study on rats.

Repair of bone deficiencies in the craniofacial skeleton remains a challenging clinical problem. The aim of this study was to evaluate and compare the effects of a plasma-derived albumin scaffold, alveolar osteoblasts and synthetic membrane implanted into experimental mandibular defects. Bilateral mandibular defects were created in twelve immunodeficient rats. The bone defect was filled with serum scaffold alone in left sides and scaffold combined with human alveolar osteoblast in right side defects. Implanted areas were closed directly in Group 1 (n = 6) and covered by a resorbable polyglycolic-polylactic acid membrane in Group 2 (n = 6). Bone regeneration was determined at 12 weeks as measured by and exhaustive multiplanar computed tomography analysis and histological examination. No significant differences in bone density were observed between defects transplanted with scaffold alone or scaffold seeded with osteoblasts. The use of membrane did not result in a determining factor in the grade of bone regeneration between Groups 1 and 2. Based on these results, it could be concluded that the albumin scaffold alone has osteoinductive capacity but presence of seeded ostogenic cells accelerates defect repair without being significantly influenced by covering the defect with a resorbable membrane.

Reduced graphene oxide membranes in ocular regenerative medicine.

Biological membranes are currently used in Ophthalmology in order to treat different ocular disorders. These membranes have different properties such as cellular biocompatibility and promoting wound healing. Moreover, intrinsic antimicrobial properties could also be desirable because it would allow their use reducing the risk of infections. Graphene and its derivatives are promising biomaterials that already proved their bactericidal effect. However, their clinical use is limited due to the controversial results regarding their toxicity. In this work, we have developed and characterized a reduced graphene oxide membrane (rGOM) for its use in ocular Regenerative Medicine, and studied its in vitro and in vivo biocompatibility and genotoxicity with different types of human ocular cells. We proved that rGOM allowed the growth of different ocular cells without inducing in vitro or in vivo cytotoxicity or genotoxicity in the short-term. These results indicate that rGOM may be a promising candidate in Regenerative Medicine for the treatment of different ocular pathologies.

Regeneration of mandibular osteoradionecrosis with autologous cross-linked serum albumin scaffold.

Osteoradionecrosis is one of the most severe complications of radiotherapy administered for head and neck tumors. We present the first two cases of advanced and refractory mandibular osteoradionecrosis treated by application of a novel autologous cross-linked 3D serum matrix. Patients were followed clinically and radiographically up to 24 months. Complete wound healing and intact mucosal cover were achieved in both cases. At 12 months, the radiographic values showed an almost complete regeneration of the bone defect, which continued a favourable progression increased to the maximum by 24 months after surgery. The use of an autologous serum-derived scaffold proved to be a quick, predictable, cost-effective and safe adjunct to the conservative surgical treatment of this pathology.

Development of an in-house reconstructed human epidermis model as an alternative method in skin corrosion assessment.

Defining the corrosive properties of chemical products generally involves the use of animal models for human health safety assessment. However, a few alternatives to animal experimentation are currently internationally accepted in order to reduce animal suffering. One of these alternatives makes use of in vitro reconstructed human epidermis (RhE) models and predicts corrosive potential based on the evaluation of cell viability after topical exposure. These models rely on its similarity to human skin, both functional and histological, and are currently worldwide marketed by a few private companies. In this manuscript, we describe the fundamentals of the production of a Do It Yourself (DIY) RhE model, and the operating procedures for the assessment of skin corrosion based on the guidelines proposed for the development of new alternative methods for skin corrosion. Our results indicate that the DIY-RhE model resembles the anatomy of the normal human epidermis as seen by immunohistochemical analysis. Moreover, barrier properties of DIY-RhE were assessed by the measure of Transepithelial Electrical Resistance. Applicability of DIY-RhE for the assessment of skin corrosion was evaluated by measuring cell viability after topical exposure of twelve reference chemicals for 3 and 60 min. Predictive performance resulted in 100% sensitivity, 100% specificity and 100% accuracy matching current requirements for new RhE models proposed for the discrimination of corrosives and non-corrosives.

The N125S polymorphism in the cathepsin G gene (rs45567233) is associated with susceptibility to osteomyelitis in a Spanish population.

BACKGROUND: Osteomyelitis is a bone infection, most often caused by Staphylococcus aureus, in which neutrophils play a key role. Cathepsin G (CTSG) is a bactericidal serine protease stored in the neutrophil azurophilic granules. CTSG regulates inflammation, activating matrix metalloproteinases (MMPs), and coagulation. Lactoferrin (LF), a neutrophil glycoprotein, increases CTSG catalytic activity and induces inflammation. The aim of this study was to analyze a potential association between a CTSG gene polymorphism (Asn125Ser or N125S, rs45567233), that modifies CTSG activity, and could affect susceptibility to, or outcome of, bacterial osteomyelitis. METHODS: CTSG N125S polymorphism was genotyped in 329 osteomyelitis patients and 415 controls), Blood coagulation parameters, serum CTSG activity, LF, MMP-1, MMP-13, and soluble receptor activator for nuclear factor κ B ligand (sRANKL) levels were assessed in carriers of the different CTSG genotypes. RESULTS: CTSG N125S (AG) genotype was significantly more frequent among osteomyelitis patients than controls (15.5% vs. 9.4%, p = 0.014). CTSG N125S variant G allele (AG +GG) was also more frequent among osteomyelitis patients (8.1% vs. 4.7%, p = 0.01). Serum CTSG activity and LF levels were significantly higher in osteomyelitis patients carrying the G allele compared to those with the AA genotype, (p<0.04). Serum MMP-1 was lower in the G allele carriers (p = 0.01). There was no association between these genotypes and clinical characteristics of osteomyelitis, or coagulation parameters, MMP-13, and sRANKL serum levels. CONCLUSIONS: Differences in the CTSG gene might enhance osteomyelitis susceptibility by increasing CTSG activity and LF levels.

QobuR - A new in vitro human corneal epithelial model for preclinical drug screening.

A new in vitro human corneal epithelial model (QobuR) obtained from normal limbal tissue has been developed to study ocular irritancy of different ophthalmic compounded drugs. Phenotypical characterization and trans-epithelial electrical resistance (TEER) of QobuR revealed essential similarities compared with a native human cornea, displaying functional markers and TEER values near 1500 Ωcm2 at day 7th of cellular differentiation. Using this model, ocular irritancy and barrier integrity alterations were evaluated using MTT reaction and variations in TEER. We found that some of the Non-Irritant products evaluated still damage the corneal epithelial integrity and current protocols for ocular irritancy should therefore include a barrier integrity evaluation. Moreover, in order to comprehensively evaluate corneal permeability of the active ingredients, we propose the use of QobuR as an all-in-one alternative method for evaluating ocular irritancy, barrier disruptions and permeability rates of topically applied ocular drugs to improve current in vitro drug testing procedures.

Human plasma gels: Their preparation and rheological characterization for cell culture applications in tissue engineering.

Tissue engineering is one of the fields of clinical medicine that has forged ahead in recent years, especially because of its role as a potential alternative to organ transplantation. The main aim of this study has been the development of biocompatible materials to form extracellular matrix (ECM) structures in order to provide the necessary conditions for the settlement, proliferation and differentiation of dermal cells such as fibroblasts. To this end, human plasma gels were synthesized with the addition of increasing concentrations of transglutaminase (TGase), which catalyses the formation of covalent bonds between Lys and Glu residues. These materials were structurally characterized using rheology and texturometry and were found to have good structural resistance and elasticity for fibroblast culture. A remarkable improvement in the mechanical properties of the human plasma gels was detected when the two highest TGase concentrations were tested, which may be interpreted as an increase in the number of covalent and non-covalent bonds formed between the plasma protein chains. Furthermore, a human fibroblast primary culture was seeded on human plasma scaffolds and satisfactorily proliferated at 37 °C. This was verified in the images obtained by optical microscopy (OM) and by scanning electron microscopy (SEM), which confirmed that the structure of this type of material is suitable for the growth and proliferation of dermal fibroblasts.

Silk Fibroin Films for Corneal Endothelial Regeneration: Transplant in a Rabbit Descemet Membrane Endothelial Keratoplasty.

Purpose: Develop a silk fibroin (SF)-based artificial endothelial graft for its use in a rabbit Descemet membrane endothelial keratoplasty (DMEK). Methods: Human and rabbit artificial corneal endothelial grafts were developed through the culture of human and rabbit corneal endothelial cells (CECs) on SF films. Rabbit artificial SF endothelial grafts were transplanted in a DMEK surgery into a rabbit in vivo model. Results: SF artificial endothelial grafts showed the characteristic endothelial markers: zonula occludens (ZO-1) and Na+/K+ ATPase. In a rabbit model of DMEK surgery, SF artificial endothelial graft restored the corneal transparency and thickness at 6 week of follow-up. Anterior segment optical coherence tomography revealed the SF graft as a fully integrated component in the corneal tissue, displaying a similar corneal thickness and endothelial cell count when compared with its healthy contralateral cornea. Histologic analysis showed that the SF artificial endothelial graft was attached and integrated on the surface of the corneal stroma without a significant inflammatory reaction, and rabbit CECs consisted in a monolayer that showed their characteristic markers ZO-1 and Na+/K+ ATPase, suggesting proper intercellular junctions and cellular pump function. Conclusions: We have developed SF films with biological properties that supported the growth of rabbit and human CECs, which showed normal morphology and characteristic markers; and with mechanical properties that allowed its use in a DMEK surgery, proving its in vivo functionality in a rabbit model of endothelial dysfunction.