Automatic Quantification of Epidermis Curvature in H&E Stained Microscopic Skin Image of Mice

Changes in the curvature of the epidermis layer is often associated with many skin disorders, such as ichthyoses and generic effects of ageing. Therefore, methods to quantify changes in the curvature are of a scientific and clinical interest. Manual methods to determine curvature are both laborious and intractable to large scale investigations. This paper proposes an automatic algorithm to quantify curvature of microscope images of H&E-stained murine skin. The algorithm can be divided into three key stages. First, skin layers segmentation based on colour deconvolution to separate the original image into three channels of different representations to facilitate segmenting the image into multiple layers, namely epidermis, dermis and subcutaneous layers. The algorithm then further segments the epidermis layer into cornified and basal sub-layers. Secondly, it quantifies the curvature of the epidermis layer by measuring the difference between the epidermis edge and a straight line (theoretical reference line) connecting the two far sides of the epidermis edge. Finally, the curvature measurements extracted from a large number of images of mutant mice are used to identify a list of genes responsible for changes in the epidermis curvature. A dataset of 5714 H&E microscopic images of mutant and wild type mice were used to evaluate the effectiveness of the algorithm

Versatile Optical Imaging Technique for Dynamic Monitoring and Quantitative Analysis in Tissue Engineering

Department of Biomedical EngineeringMany researches in the tissue engineering are investigating the development of technologies that have covered a broad range of applications and closely associated with the tissue regeneration and replacement of lost or damaged tissues as well as tissue manipulation. However, there are challenges regarding monitoring and assessing outcomes to analyze a variety of morphological and structural changes in tissue engineering applications. Most tissue engineering studies have utilized histopathological techniques for morphological analysis and evaluation of the tissues. Although the conventional methods provided a high definition and clear distinction under optical microscopy, it has still limitations in the visualization of tissue constructs without destruction of the tissues. Also, these methods have not allowed a volumetric assessment and functional information. Due to the destructive process and limited information in a two-dimensional approach, the conventional methods were difficult not only to analyze the specimens at continuous time points but also to compare inconsistencies of the results between different samples. For these reasons, there are clear needs for the development of advanced optical imaging techniques available for non-invasive and consistent observation and quantitative analysis in tissue engineering applications. Optical coherence tomography (OCT) has emerged as appropriate candidate for studying tissue morphology dynamically and quantitatively. OCT equips optimal imaging characteristics for dynamic monitoring because it offers cross-sectional, high-resolution, real-time tissue imaging in a non-invasive manner. Unlike most optical imaging techniques, OCT does not require any contrast agent or labeling process even it provides a deep penetration depth of about 2 mm in the tissue. Here, we utilized OCT technique to carry out application for the tissue engineering research ranging from the observation of biological tissues, dynamic monitoring, and quantitative analysis, as well as fabrication of image-guided engineered tissue. In the chapter 2, we utilized 3D OCT imaging to observe the tissue regeneration after laser irradiation, epidermal biopsy, and skin incision in in vitro and in vivo skin model. We utilized OCT system to monitor and analyze the wound recovery process after laser irradiation on the engineered skin. Also, we presented a quantitative evaluation of drug efficiency that affect the wound recovery on the engineered skin model after epidermal biopsy. Next, we analyzed quantitatively a recovery process of the wound width and depth in skin incised rat model in vivo with tissue adhesives treatment under the OCT monitoring. In the chapter 3, we utilized optical coherence microscopy (OCM) imaging modality to observe and quantitatively analyze the morphological changes of biological tissue in subcellular level. We introduced depth trajectory-tracking technique to acquire homogenous quality OCM images regardless of the height difference of the sample surface. Also, we developed the serial block-face OCM (SB-OCM) system to acquire the whole tissue information by repeating tissue sectioning and image acquisition using the serial block-face imaging technique. In the chapter 4, we developed the hand-held probe based portable OCT system for convenience in human target studies. We monitored and quantitatively analyzed various changes in the human skin using the hand-held probe based portable OCT system. Especially, we studied quantitative analysis of human skin wrinkle in terms of depth and volume as well as roughness parameters in comparison with conventional platforms. In the chapter 5, we suggested the feasibility to fabricate the engineered tissue based on a volumetric information of optical imaging. Here, we studied a fabrication of wrinkle mimicked engineered skin for anti-aging assessment and a protocol of imaging guided personalized engineered cornea for cornea transplantation. In conclusion, we confirmed that OCT system was able to provide various quantitative information from the biological tissues by its advantages such as high-resolution, non-invasive, label-free, deep penetration depth with real-time imaging. These characteristics of OCT imaging enables the quantitative analysis of tissue recovery and replacement as well as tissue manipulation in the tissue engineering research.clos

Development and characterization of novel vehicles for topical drug delivery

Tese de doutoramento, Farmácia (Tecnologia Farmacêutica), Universidade de Lisboa, Faculdade de Farmácia, 2016Topical drug delivery is challenging since the skin acts as a natural and protective barrier. The skin has been an important route for drug delivery when topical, local or systemic effects are desired. The outcome of topical dermatological drug treatment is significantly influenced by the choice of vehicle. In recent years there has been an increased interest in developing improved delivery systems and, exploring new ways of using approved excipients, such as, starch. Due to its unique properties, starch has been extensively used in various topical pharmaceutical application, i.e. as a sensorial enhancer, a stabilizer and drug delivery polymer, providing protection and control release of the drug molecule. The base-concept of this study was to develop and characterize novel starch-based vehicles for dermatological application, easily scaled-up to industry and produced by methods that can allow the decrease of production costs, and further investigate the resulting systems behavior in in vitro and in vivo conditions. Starch-based vehicles were prepared successfully using QbD approach with the understanding of the high risk process and formulation parameters involved and optimized design space with a multifactorial combination of critical parameters to obtain predetermined specifications. Three different model drugs were incorporated into the optimized starch-based vehicles. Minocycline hydrochloride (MH) was incorporated in Pickering emulsions, a human neutrophil elastase inhibitor (ER143), a new molecule developed by the MedChem Group at iMed.ULisboa, was encapsulated into starch nanocapsules and melatonin was added on Pickering emulsions sunscreen, in order to fully characterize these new formulations, and further study its topical delivery and in vitro and in vivo efficacy. The in vitro antibacterial activity studies for Pickering emulsions containing MH revealed that the released drug exceeded the minimum inhibitory concentration of MH against S.aureus. In vitro release studies showed a prolonged release of the MH, with an initial burst effect. Regarding in vitro permeation studies, MH does not pass through the entire skin layer, suggesting a minimal potential for the systemic absorption of the MH upon topical administration. In vivo results showed that topical administration of MH was effective in S. aureus superficial infections treatment. Starch nanocapsules presented a mean particle size ranging from 200 to 250 nm and a positive zeta potential. In vitro permeation studies showed that the starch nanocapsules were suitable for the delivery of ER143, allowing a high control of the drug release, contributing to a high skin retention and/or permeation profiles of ER143. In vivo results showed that erythema and edema were attenuated in 98%, following the local application of ER143-loaded starch nanocapsules. Regarding Pickering emulsions sunscreen, formulation studies demonstrated that starch particles presented no intrinsic photoprotection properties, they proved to be a sun protection factor promoter by a synergistic effect. Besides the excellent sunscreen activity confirmed by in vitro and in vivo results, the final formulations proved to be also suitable for topical use according to the rheological assessment and stability throughout the study period (3 months). Additionally, the safety and biological effects of the placebos (vehicles without drug) was assessed by using both in vitro and in vivo studies, as an adequate equilibrium between the safety and efficacy effects. Overall, these findings highlight the starch-based vehicles as promising for the development of topical delivery systems, covering innovative therapeutic approaches

Using Nanotechnology to Improve Soft Tissue Adhesion to Intraosseous Transcutaneous Amputation Prostheses (ITAP)

Intraosseous Transcutaneous Amputation Prosthesis (ITAP) is a new generation device in limb replacement that may solve the issues of the externally fixed stump socket prosthesis, helping to restore the original limb function. ITAP is implanted into the medullary cavity of bone with an abutment that protrudes through the skin for limb attachment. The skin-implant interface is maintained with a flange, which resides below the epithelium, and is designed with pores to enhance soft tissue sub-epithelial ingrowth. This goals of this design are to stabilises the soft tissue, reducing the relative movements and seals the skin ITAP interface preventing bacterial infection. The current ITAP design includes a bi-dimensional flange that results in poor soft tissue attachment and, consequently, in the failure of the implant. My thesis aims to investigate firstly the effect of a new three dimensional porous flange on soft tissue attachment and ingrowth both in-vivo and in a clinical study with animal patients. Secondly, to improve epithelial and sub-epithelial attachment to the flange in-vitro and ex-vivo by modifying the surface of the ITAP with TiO2 nanotubes which have been shown to enhance cell attachment and have the potential to prevent downgrowth and infection around ITAP. The key original contributions to knowledge from my thesis are that firstly porous flanges increase the soft tissue attachment and ingrowth, contributing to stabilize the implant (p-value = 0.01 comparing 1000µm and 1250µm porosity with smooth titanium).. Moreover the size of nanotubes around 110nm, significantly increase the epithelial and sub-epithelial tissue attachment compared to the currently used smooth titanium, in- vivo, in vitro and ex-vivo, in order to create a stronger bound on the interface with the ITAP. In conclusion the combination of the porosity of the flange and the TiO2 nanotubes can significantly increase the soft tissue attachment and ingrowth to the flange in comparison with the commercially used bi-dimensional and smooth ITAPs

A dosimetric skin study on postmastectomy breast cancer patients undergoing radiation therapy

Ph.DDOCTOR OF PHILOSOPH

Senescence

The book "Senescence" is aimed to describe all the phenomena related to aging and senescence of all forms of life on Earth, i.e. plants, animals and the human beings. The book contains 36 carefully reviewed chapters written by different authors, aiming to describe the aging and senescent changes of living creatures, i.e. plants and animals

Wound Repair and Regeneration

Wounds are a largely unrecognized, spiraling epidemic that affect millions of people world-wide. They are complex and involve temporal and spatial involvement of many different cell types and tissue processes. Recent advances in our understanding of wound repair and regeneration, as well as the many novel and exciting approaches aimed at healing chronic/acute wounds and reducing scar formation, make this a pertinent time for a Special Issue aimed at overviewing this important field. The goal of this book is to provide a summary of the field, describe its impact, as well as introduce the recent advances in understanding the mechanisms that underpin wound healing and scar formation. The articles include in this book highlight new developments in therapeutic approaches for wound repair including the use of nanomedicine and biomaterials to deliver cells and/or drugs to promote healing. Cellular responses that underpin angiogenesis, inflammation, proliferation and remodeling, as well as advances in cytoskeletal interactions in keratinocytes and fibroblast cell functions. Wound remodeling and scar formation including the roles of growth factors, cytokines and stem cells are included

An investigation into the efficacy of single low dose of insulin in the prevention of excessive cutaneous scarring in breast surgery

Early human fetuses have the ability to heal wounds by completely regenerating tissues, leaving no evidence of scarring. However in the adult scarring is the inevitable endpoint of the wound healing process. Sometimes these scars can be pathological in nature causing both functional and aesthetic problems to those affected. Every year millions of people around the globe acquire problematic or pathological scars either whilst undergoing surgery or from traumatic injuries and at present there remain a severely limited number of pharmacological treatment options to offer these patients. Importantly currently there exists no treatment that can either eliminate or reliably reduce acquired scars. Not only is the treatment of acquired scars problematic but also the clinical assessment of scars is largely subjective in nature and frequently relies on assessment scales that show large amounts of inter-rater variation and lack quantification. Especially subjective is the measurement of scar colour, which can be markedly different from the surrounding skin and cause significant distress to the patient. Without an objective assessment framework clinicians cannot reliably examine scars nor gauge responses to any treatment. The aim of this thesis is thus two-fold. Firstly a new anti-scarring treatment in the form of insulin will be tested in a randomised, double blind, intra-patient, placebo controlled trial where patients undergoing elective bilateral breast surgery will have low-dose insulin injected subcutaneously to one breast and placebo to the other at the time of surgery. Patients will be followed up for 12 months and their scars compared to examine the therapeutic effect of insulin upon scars. Secondly the thesis aims to test the validity of new methods of assessing the scar colour of a subset of patients within the insulin trial using previously untested photographic devices and software. These devices are hoped to add much needed quantification to scar assessment.Open Acces