Biochemical Characterization and Bio-evaluation of Collagen and Collagen Peptides Extracted and Purified from Fish Skin: In vitro and In vivo Studies on Antiarthritic and Wound Healing Properties

In fish processing plants, there is huge amount of skin that is left as the waste. When this skin is taken and processed into fish collagen, it will save large amount of money that is used for extraction of collagen from other animal s.Fish collagen can be used as an alternative to replace mammalian collagen, especially collagen extracted from bovine, when we consider the outbreak of bovine spongiform encephalopathy (BSE), transmissible spongiform encephalopathy (TSE) and the foot - and-mouth disease (FMD) issues. BSE and TSE are progressive neurological disorders affecting cattles caused by proteinacious infectious particles called prions.The study aims in producing collagen that has been extracted from fish skin to replace other animal collagen so as to overcome the problem of other animal collagen issues. Also the study utilized the abandoned fish waste produced by fish processing industry since bone, skin, fin and scales of fish can be a useful source of collagen.

Tissue response and wound healing after placement of two types of bioengineered grafts containing vital cells in submucosal maxillary pouches: an experimental pilot study in rabbits

PURPOSE: This pilot study evaluated the wound healing and tissue response after placement of two different skin substitutes in subgingival mucosal pouches in rabbits. MATERIALS AND METHODS: Four rabbits were selected to receive a commercially available skin substitute consisting of a collagen matrix with fibroblasts and an epithelial layer (test membrane 1) and a prototype device consisting of a collagen matrix with fibroblasts only (test membrane 2). In each rabbit, two horizontal incisions were made in the buccal alveolar mucosa of the maxilla bilaterally to create submucosal pouches. Three pouches in each animal were filled with either the test 1 or test 2 membranes, and one pouch was left without a membrane (sham-operated control). All rabbits were sacrificed after a healing period of 4 weeks, and histologic samples were prepared and examined. RESULTS: After a healing period of 1 month, both tested membranes were still visible in the sections. Test membrane 1 was still bilayered, contained inflammatory cells in its center, and was encapsulated by a thick fibrous tissue. Numerous ectopic calcifications were evident in the collagenous part of the membrane and in association with some basal epithelial cells. Test membrane 2 was also encapsulated in fibrous tissue, with inflammatory cells present only between the fibrous encapsulation and the remnants of the membrane. For test membrane 2, no calcifications were visible. CONCLUSIONS: Test membrane 1 seemed to be more resistant to degradation, but there was also a more pronounced inflammatory reaction in comparison to test membrane 2, especially in the vicinity of the keratinocytes. The significance of the ectopic calcifications, along with that of the resorption or degradation processes of both tested membranes, must be evaluated in future experimental studies, with different time points after implantation examine

Zinc deficiency and its inherited disorders - A review

Zinc is an essential trace element required by all living organisms because of its critical roles both as a structural component of proteins and as a cofactor in enzyme catalysis. The importance of zinc in human metabolism is illustrated by the effects of zinc deficiency, which include a diminished immune response, reduced healing and neurological disorders. Furthermore, nutritional zinc deficiency can be fatal in newborn or growing animals. While zinc deficiency is commonly caused by dietary factors, several inherited defects of zinc deficiency have been identified. Acrodermatitis enteropathica is the most commonly described inherited condition found in humans. In several of the few cases that have been reported, this disorder is associated with mutations in the hZIP4 gene, a member of the SLC39 family, whose members encode membranebound putative zinc transporters. Mutations in other members of this family or in different genes may account for other cases of acrodermatitis in which defects in hZIP4 have not been detected. Another inherited form of zinc deficiency occurs in the lethal milk mouse, where a mutation in ZnT4 gene, a member of the SLC30 family of transmembrane proteins results in impaired secretion of zinc into milk from the mammary gland. A similar disorder to the lethal milk mouse occurs in humans. In the few cases studied, no changes in ZnT4 orthologue, hZnT4, were detected. This, and the presence of several minor phenotypic differences between the zinc deficiency in humans and mice, suggests that the human condition is caused by defects in genes that are yet to be identified. Taking into account the fact that there are no definitive tests for zinc deficiency and that this disorder can go undiagnosed, plus the recent identification of multiple members of the SCL30 and SLC39, it is likely that mutations in other genes may underlie additional inherited disorders of zinc deficiency.

PLASMACYTOID DENDRITIC CELLS SENSE SKIN INJURY AND PROMOTE WOUND HEALING THROUGH TYPE I INTERFERONS

Plasmacytoid dendritic cells (pDCs) are a rare population of circulating cells, which selectively express intracellular Toll-like receptors (TLR)-7 and TLR-9 and have the capacity to produce large amounts of type I IFNs (IFN-a/b) in response to viruses or host derived nucleic acid containing complexes. pDCs are normally absent in skin but accumulate in the skin of psoriasis patients where their chronic activation to produce IFN-a/b drives the disease formation. Whether pDCs and their activation to produce IFN-a/b play a functional role in healthy skin is unknown. Here we show that pDCs are rapidly and transiently recruited into healthy human and mouse skin upon epidermal injury. Infiltrating pDCs were found to sense nucleic acids in wounded skin via TLRs, leading to the production of IFN-a/b. The production of IFN-a/b was paralleled by a short lived expression of cathelicidins, which form complexes with extracellular nucleic acids and activated pDCs to produce IFN-a/b in vitro. In vivo, cathelicidins were sufficient but not necessary for the induction of IFN-a/b in wounded skin, suggesting redundancy of this pathway. Depletion of pDCs or inhibition of IFN-a/bR signaling significantly impaired the inflammatory response and delayed re-epithelialization of skin wounds. Thus we uncover a novel role of pDCs in sensing skin injury via TLR mediated recognition of nucleic acids and demonstrate their involvement in the early inflammatory process and wound healing response through the production of IFN-a/b.

Multiple functions of gingival and mucoperiosteal fibroblasts in oral wound healing and repair

Fibroblasts are cells of mesenchymal origin. They are responsible for the production of most extracellular matrix in connective tissues and are essential for wound healing and repair. In recent years, it has become clear that fibroblasts from different tissues have various distinct traits. Moreover, wounds in the oral cavity heal under very special environmental conditions compared with skin wounds. Here, we reviewed the current literature on the various interconnected functions of gingival and mucoperiosteal fibroblasts during the repair of oral wounds. The MEDLINE database was searched with the following terms: (gingival OR mucoperiosteal) AND fibroblast AND (wound healing OR repair). The data gathered were used to compare oral fibroblasts with fibroblasts from other tissues in terms of their regulation and function during wound healing. Specifically, we sought answers to the following questions: (i) what is the role of oral fibroblasts in the inflammatory response in acute wounds; (ii) how do growth factors control the function of oral fibroblasts during wound healing; (iii) how do oral fibroblasts produce, remodel and interact with extracellular matrix in healing wounds; (iv) how do oral fibroblasts respond to mechanical stress; and (v) how does aging affect the fetal-like responses and functions of oral fibroblasts? The current state of research indicates that oral fibroblasts possess unique characteristics and tightly controlled specific functions in wound healing and repair. This information is essential for developing new strategies to control the intraoral wound-healing processes of the individual patient.

Mathematical modelling of chronic wound healing

Chronicwounds fail to proceed through an orderly process to produce anatomic and functional integrity and are a significant socioeconomic problem. There is much debate about the best way to treat these wounds. In this thesis we review earlier mathematical models of angiogenesis and wound healing. Many of these models assume a chemotactic response of endothelial cells, the primary cell type involved in angiogenesis. Modelling this chemotactic response leads to a system of advection-dominated partial differential equations and we review numerical methods to solve these equations and argue that the finite volume method with flux limiting is best-suited to these problems. One treatment of chronic wounds that is shrouded with controversy is hyperbaric oxygen therapy (HBOT). There is currently no conclusive data showing that HBOT can assist chronic wound healing, but there has been some clinical success. In this thesis we use several mathematical models of wound healing to investigate the use of hyperbaric oxygen therapy to assist the healing process - a novel threespecies model and a more complex six-species model. The second model accounts formore of the biological phenomena but does not lend itself tomathematical analysis. Bothmodels are then used tomake predictions about the efficacy of hyperbaric oxygen therapy and the optimal treatment protocol. Based on our modelling, we are able to make several predictions including that intermittent HBOT will assist chronic wound healing while normobaric oxygen is ineffective in treating such wounds, treatment should continue until healing is complete and finding the right protocol for an individual patient is crucial if HBOT is to be effective. Analysis of the models allows us to derive constraints for the range of HBOT protocols that will stimulate healing, which enables us to predict which patients are more likely to have a positive response to HBOT and thus has the potential to assist in improving both the success rate and thus the cost-effectiveness of this therapy.

Effect of nutritional supplements on wound healing in home-nursed elderly: a randomized trial

 Objective: The objective was to determine whether provision of oral nutritional supplements, delivered by community nurses, could improve nutritional status and wound healing in home-nursed elderly. Methods: This was a double-blind, randomized trial in 50 elderly patients referred for wound management. Patients received 237 mL/d of 4 or 8 kJ/mL of an oral nutritional supplement for 4 wk. Nutritional status was measured with the Subjective Global Assessment and the Mini-Mental State Examination questionnaire to determine cognitive function and wound characteristics to assess healing. Differences between variables were examined with the Mann-Whitney or Student's t test for comparing two groups, one-way analysis of variance when there was more than two groups, and chi-square analysis for comparing two categorical variables. Associations between variables were examined with Pearson's correlation and regression analysis. Results: At baseline, 34% subjects were moderately malnourished and 8% were severely malnourished. In both groups, there was significantly greater improvement in Mini-Mental State Examination scores at week 4 (95% confidence interval -2.0 to -0.001, P = 0.04) and a greater decrease in the wound effusion score (95% confidence interval -2.0 to 0.0, P = 0.045). Median length of stay did not differ between groups (P > 0.05). Conclusions: Malnutrition is common in elderly patients who are nursed at home for wound management. Provision of energy- and protein-dense oral supplements by community nurses is effective in improving some indices of wound healing and cognitive function in this group. Although further study is needed to determine the effect on length of stay, the nutritional needs of this vulnerable group should not be overlooked. © 2005 Elsevier Inc. All rights reserved.

Abarema cochliacarpos: Gastroprotective and ulcer-healing activities

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Antimicrobial Brazilian propolis (EPP-AF) containing biocellulose membranes as promising biomaterial for skin wound healing

Among remarkable discoveries concerning propolis, such as antifungal, antiviral, and antioxidant activities, its anti-inflammatory, and mainly its antibacterial, properties deserve special attention when skin wound healing is concerned. Based on this and knowing the distinctive performance of bacterial (BC) membranes on wound healing, in this work it is proposed to demonstrate the potent antimicrobial activity and wound healing properties of a novel propolis containing biocellulose membrane. The obtained propolis/BC membrane was able to adsorb propolis not only on the surface, but also in its interstices demonstrated by scanning electron microscopy, X-ray diffraction, Fourier transform infrared (FT-IR) spectroscopy, and thermogravidimetric assays. Additionally, the polyphenolic compounds determination and the prominent antibacterial activity in the membrane are demonstrated to be dose dependent, supporting the possibility of obtaining propolis/BC membranes at the desired concentrations, taking into consideration its application and its skin residence time. Finally, it could be suggested that propolis/BC membrane may favor tissue repair in less time and more effectively in contaminated wounds. © 2013 Hernane da Silva Barud et al.

Effect of temperature and diet on wound healing in Atlantic salmon (Salmo salar L.).

Compromised skin integrity of farmed Atlantic salmon, commonly occurring under low temperature and stressful conditions, has major impacts on animal welfare and economic productivity. Even fish with minimal scale loss and minor wounds can suffer from secondary infections, causing downgrading and mortalities. Wound healing is a complex process, where water temperature and nutrition play key roles. In this study, Atlantic salmon (260 g) were held at different water temperatures (4 or 12 °C) and fed three different diets for 10 weeks, before artificial wounds were inflicted and the wound healing process monitored for 2 weeks. The fish were fed either a control diet, a diet supplemented with zinc (Zn) or a diet containing a combination of functional ingredients in addition to Zn. The effect of diet was assessed through subjective and quantitative skin histology and the transcription of skin-associated chemokines. Histology confirmed that wound healing was faster at 12 °C. The epidermis was more organised, and image analyses of digitised skin slides showed that fish fed diets with added Zn had a significantly larger area of the epidermis covered by mucous cells in the deeper layers after 2 weeks, representing more advanced healing progression. Constitutive levels of the newly described chemokines, herein named CK 11A, B and C, confirmed their preferential expression in skin compared to other tissues. Contrasting modulation profiles at 4 and 12 °C were seen for all three chemokines during the wound healing time course, while the Zn-supplemented diets significantly increased the expression of CK 11A and B during the first 24 h of the healing phase.

Ex vivo investigation of novel wound healing therapies and development of a 3-D human skin equivalent wound model

It has previously been found that complexes comprised of vitronectin and growth factors (VN:GF) enhance keratinocyte protein synthesis and migration. More specifically, these complexes have been shown to significantly enhance the migration of dermal keratinocytes derived from human skin. In view of this, it was thought that these complexes may hold potential as a novel therapy for healing chronic wounds. However, there was no evidence indicating that the VN:GF complexes would retain their effect on keratinocytes in the presence of chronic wound fluid. The studies in this thesis demonstrate for the first time that the VN:GF complexes not only stimulate proliferation and migration of keratinocytes, but also these effects are maintained in the presence of chronic wound fluid in a 2-dimensional (2-D) cell culture model. Whilst the 2-D culture system provided insights into how the cells might respond to the VN:GF complexes, this investigative approach is not ideal as skin is a 3-dimensional (3-D) tissue. In view of this, a 3-D human skin equivalent (HSE) model, which reflects more closely the in vivo environment, was used to test the VN:GF complexes on epidermopoiesis. These studies revealed that the VN:GF complexes enable keratinocytes to migrate, proliferate and differentiate on a de-epidermalised dermis (DED), ultimately forming a fully stratified epidermis. In addition, fibroblasts were seeded on DED and shown to migrate into the DED in the presence of the VN:GF complexes and hyaluronic acid, another important biological factor in the wound healing cascade. This HSE model was then further developed to enable studies examining the potential of the VN:GF complexes in epidermal wound healing. Specifically, a reproducible partial-thickness HSE wound model was created in fully-defined media and monitored as it healed. In this situation, the VN:GF complexes were shown to significantly enhance keratinocyte migration and proliferation, as well as differentiation. This model was also subsequently utilized to assess the wound healing potential of a synthetic fibrin-like gel that had previously been demonstrated to bind growth factors. Of note, keratinocyte re-epitheliasation was shown to be markedly improved in the presence of this 3-D matrix, highlighting its future potential for use as a delivery vehicle for the VN:GF complexes. Furthermore, this synthetic fibrin-like gel was injected into a 4 mm diameter full-thickness wound created in the HSE, both keratinocytes and fibroblasts were shown to migrate into this gel, as revealed by immunofluorescence. Interestingly, keratinocyte migration into this matrix was found to be dependent upon the presence of the fibroblasts. Taken together, these data indicate that reproducible wounds, as created in the HSEs, provide a relevant ex vivo tool to assess potential wound healing therapies. Moreover, the models will decrease our reliance on animals for scientific experimentation. Additionally, it is clear that these models will significantly assist in the development of novel treatments, such as the VN:GF complexes and the synthetic fibrin-like gel described herein, ultimately facilitating their clinical trial in the treatment of chronic wounds.

A two-compartment mechanochemical model of the roles of transforming growth factor-beta and tissue tension in dermal wound healing

The repair of dermal tissue is a complex process of interconnected phenomena, where cellular, chemical and mechanical aspects all play a role, both in an autocrine and in a paracrine fashion. Recent experimental results have shown that transforming growth factor-beta (TGF-beta) and tissue mechanics play roles in regulating cell proliferation, differentiation and the production of extracellular materials. We have developed a 1D mathematical model that considers the interaction between the cellular, chemical and mechanical phenomena, allowing the combination of TGF-beta and tissue stress to inform the activation of fibroblasts to myofibroblasts. Additionally, our model incorporates the observed feature of residual stress by considering the changing zero-stress state in the formulation for effective strain. Using this model, we predict that the continued presence of TGF-beta in dermal wounds will produce contractures due to the persistence of myofibroblasts; in contrast, early elimination of TGF-beta significantly reduces the myofibroblast numbers resulting in an increase in wound size. Similar results were obtained by varying the rate at which fibroblasts differentiate to myofibroblasts and by changing the myofibroblast apoptotic rate. Taken together, the implication is that elevated levels of myofibroblasts is the key factor behind wounds healing with excessive contraction, suggesting that clinical strategies which aim to reduce the myofibroblast density may reduce the appearance of contractures.

Modelling the interaction of keratinocytes and fibroblasts during normal and abnormal wound healing processes

The crosstalk between fibroblasts and keratinocytes is a vital component of the wound healing process, and involves the activity of a number of growth factors and cytokines. In this work, we develop a mathematical model of this crosstalk in order to elucidate the effects of these interactions on the regeneration of collagen in a wound that heals by second intention. We consider the role of four components that strongly affect this process: transforming growth factor-beta, platelet-derived growth factor, interleukin-1 and keratinocyte growth factor. The impact of this network of interactions on the degradation of an initial fibrin clot, as well as its subsequent replacement by a matrix that is mainly comprised of collagen, is described through an eight-component system of nonlinear partial differential equations. Numerical results, obtained in a two-dimensional domain, highlight key aspects of this multifarious process such as reepithelialisation. The model is shown to reproduce many of the important features of normal wound healing. In addition, we use the model to simulate the treatment of two pathological cases: chronic hypoxia, which can lead to chronic wounds; and prolonged inflammation, which has been shown to lead to hypertrophic scarring. We find that our model predictions are qualitatively in agreement with previously reported observations, and provide an alternative pathway for gaining insight into this complex biological process.