Uso de quitina e quitosana como adsorventes de amônia de efluentes aquícolas: revisão de literatura / Use of chitin and quitosan as adsorvents of ammonia of aquaculture effluents: a literature review / Uso de quitina y quitosana como adsorbentes de amonia de efluentes acuícolas: revisión de literatura

Os resíduos provenientes da aquicultura são derivados da ração e da excreção dos peixes e podem estar sedimentados, suspensos ou dissolvidos, ocasionando elevados valores de DBO, DQO, nitrogênio e fósforo. A produção de camarões no Brasil tem gerado elevadas quantidades de resíduos sólidos, tendo em vista que os exoesqueletos dos camarões correspondem a cerca de 40% do seu peso total, resultando num forte impacto ambiental. Diversas pesquisas envolvendo a quitina estão sendo desenvolvidas na área de tratamento de água, devido principalmente a sua capacidade de formar filme, sendo utilizada em sistemas filtrantes. Este polissacarídeo também pode ser utilizado como agente floculante no tratamento de efluentes, como adsorvente na clarificação de óleos, e principalmente na produção de quitosana. Atualmente a quitosana possui aplicações multidimensionais, desde áreas como a nutrição humana, biotecnologia, ciência dos materiais, indústria farmacêutica, agricultura, terapia genética e proteção ambiental. A quitosana é muito eficiente na remoção de poluentes em diferentes concentrações. Apresenta alta capacidade e grande velocidade de adsorção, boa eficiência e seletividade tanto em soluções que possuem altas ou baixas concentrações. O uso da biotecnologia, através do processo de adsorção utilizando adsorventes naturais e baratos, como a quitina e quitosana, minimiza os impactos ambientais da aquicultura tanto em relação aos provocados pelo lançamento de efluentes no meio ambiente quanto aos causados pelo descarte inadequado dos resíduos do processamento de camarões.(AU)

Aquaculture residues are derived from fish feed and excretion and may be sedimented, suspended or dissolved, resulting in high BOD, COD, nitrogen and phosphorus values. Shrimp production in Brazil has generated high amounts of solid waste, since shrimp exoskeletons account for about 40% of their total weight, resulting in a strong environmental impact. Several researches involving chitin are being developed in the area of water treatment, mainly due to its ability to form film, being used in filter systems. This polysaccharide can also be used as a flocculating agent in the treatment of effluents, as an adsorbent in the clarification of oils, and especially in the production of chitosan. Currently, chitosan has multidimensional applications, from areas such as human nutrition, biotechnology, materials science, pharmaceutical industry, agriculture, gene therapy and environmental protection. Chitosan is very efficient in the removal of pollutants at different concentrations. It presents high capacity and high adsorption velocity, good efficiency and selectivity both in solutions that have high or low concentrations. The use of biotechnology, through the adsorption process using natural and cheap adsorbents such as chitin and chitosan, minimizes the environmental impacts of aquaculture both in relation to those caused by the release of effluents into the environment and those caused by the inappropriate disposal of processing residues of shrimps.(AU)

Los residuos procedentes de la acuicultura se derivan de la ración y de la excreción de los peces y pueden estar sedimentados, suspendidos o disueltos, ocasionando elevados valores de DBO, DQO, nitrógeno y fósforo. La producción de camarones en Brasil ha generado grandes cantidades de residuos sólidos, teniendo en cuenta que los exoesqueletos de los camarones corresponden a cerca del 40% de su peso total, resultando en un fuerte impacto ambiental. Varias investigaciones involucrando la quitina se están desarrollando en el área de tratamiento de agua, debido principalmente a su capacidad de formar película, siendo utilizada en sistemas filtrantes. Este polisacárido también puede ser utilizado como agente floculante en el tratamiento de efluentes, como adsorbente en la clarificación de aceites, y principalmente en la producción de quitosana. Actualmente la quitosana posee aplicaciones multidimensionales, desde áreas como la nutrición humana, biotecnología, ciencia de los materiales, industria farmacéutica, agricultura, terapia genética y protección ambiental. La quitosana es muy eficiente en la eliminación de contaminantes en diferentes concentraciones. Presenta alta capacidad y gran velocidad de adsorción, buena eficiencia y selectividad tanto en soluciones que poseen altas o bajas concentraciones. El uso de la biotecnología, a través del proceso de adsorción utilizando adsorbentes naturales y baratos, como la quitina y quitosana, minimiza los impactos ambientales de la acuicultura tanto en relación a los provocados por el lanzamiento de efluentes en el medio ambiente en cuanto a los causados por el descarte inadecuado de los residuos del procesamiento de camarones.(AU)

Enhancement of cellular activity in hyperglycemic mice dermal wounds dressed with chitosan-alginate membranes

The use of specially designed wound dressings could be an important alternative to facilitate the healing process of wounds in the hyperglycemic state. Biocompatible dressings combining chitosan and alginate can speed up wound healing by modulating the inflammatory phase, stimulating fibroblast proliferation, and aiding in remodeling phases. However, this biomaterial has not yet been explored in chronic and acute lesions of diabetic patients. The aim of this study was to evaluate the effect of topical treatment with a chitosan-alginate membrane on acute skin wounds of hyperglycemic mice. Diabetes mellitus was induced by streptozotocin (60 mg · kg-1 · day-1 for 5 days, intraperitoneally) and the cutaneous wound was performed by removing the epidermis using a surgical punch. The results showed that after 10 days of treatment the chitosan and alginate membrane (CAM) group exhibited better organization of collagen fibers. High concentrations of interleukin (IL)-1α, IL-1β, granulocyte colony-stimulating factor (G-CSF), and tumor necrosis factor-alpha (TNF-α) were detected in the first and second days of treatment. G-CSF and TNF-α level decreased after 5 days, as well as the concentrations of TNF-α and IL-10 compared with the control group (CG). In this study, the inflammatory phase of cutaneous lesions of hyperglycemic mice was modulated by the use of CAM, mostly regarding the cytokines IL-1α, IL-1β, TNF-α, G-CSF, and IL-10, resulting in better collagen III deposition. However, further studies are needed to better understand the healing stages associated with CAM use.

A Therapeutic Oral Vaccine Candidate against Propionibacterium acnes: Preparation and Immunological Evaluation of Nanoparticles Encapsulated Sialidase-CAMP Fusion Protein

Abstract Acne Vulgaris is a common skin disease caused by Propionibacterium acnes, an anaerobic microbiota of human skin that plays a vital role in the pathology of acne. The aim of this study was to prepare nanoparticles containing an acne recombinant protein and determine its ability as an oral acne vaccine in mice. The recombinant Sialidase-CAMP gene was expressed and purified in a prokaryotic host. The chitosan nanoparticles containing the recombinant protein were prepared, encapsulated, and administered by both oral and subcutaneous routes to Balb/c mice. Sera IgA and IgG and stool IgA titers were measured by ELISA, and the immunized mice were challenged against P. acnes. A 65 kDa recombinant protein was confirmed by SDS-PAGE and western blot. The size and zeta potential of nanoparticles were 80 nm and +18 mV, respectively. After oral immunization, the serum IgG and IgA titers were 1:3200 and 1:16, respectively, and the stool IgA titer was 1:8. In the subcutaneous route, the serum IgG titer was 1:51200. Immunized mice showed no inflammation in the ear of challenged mice. It is the first study that examines a chitosan-nanoparticulated acne fusion protein as an applicable acne vaccine candidate with appropriate immunogenicity potential. Further studies are required to validate the clinical usefulness of this vaccine candidate.

Avaliação in vitro da atividade antimicrobiana de nanoestrutura de quitosana / In vitro avaliation of antimicrobial activity of chitosan nanostructure

A quitosana é um polímero capaz de apresentar atividade antimicrobiana e na sua forma nanoestruturada acredita-se que apresente maior desempenho. Portanto, este trabalho avaliou a capacidade antimicrobiana da nanoquitosana via diluições em microplaca. Utilizou-se quatro bactérias Escherichia coli, Enterobacter cloacae, Salmonella sp. e Staphylococus aureus em diferentes concentrações de nanoestrutura. Observou que em todas as concentrações (0,26 µg ml-1 a 19,7 µg ml-1) houve inibição, além disso, percebeu-se uma constância na absorção ao longo do tempo para algumas concentrações, indicando possível atividade bacteriostática da nanoestrutura. Assim, a nanoestrutura de quitosana apresentou atividade antimicrobiana, com ação bacteriocida e bacterioestática sobre os microrganismos estudados.

Avaliação antimicrobiana da nanoquitosana incorporada no hidrogel de PVA e propilenoglicol / Antimicrobial evaluation of PVA and propylene glycol hydrogel integrated nanochitosan

A nanoquitosana (NQ) possui potencial antimicrobiano contra microrganismos causadores de Doenças Transmitidas por Alimentos. Este trabalho busca determinar o efeito antimicrobiano da NQ em hidrogéis para substituir os produtos assépticos e sanitizantes convencionais. O hidrogel de propilenoglicol foi testado em superfície de aço inox em E. coli, apresentando crescimento de 303±53 UFC, inferior ao controle 481,5±62,5 UFC. O gel de PVA foi testado pelo método de disco-difusão contra E. coli, com halo de inibição de 2,7±0,2 cm (NQ 71,43 µg.mL-1) e 2,3±0,3 cm (NQ 142,85 µg.mL-1), e S. typ, com halo de inibição de 3,0±0,2 cm e 2,8±0,2 cm, com NQ 71,43 µg.mL-1 e 142,85 µg.mL-1, respectivamente. Os resultados indicam potencial uso da NQ em produtos sanitizantes, para isso são necessários testes toxicológicos e caracterização das nanoestruturas.

Inhibición del crecimiento y modificación genética de Phytophthora capsici usando quitosano de bajo grado de polimerización / Growth inhibition and genetic modification of Phytophthora capsici using chitosan with low degree of polymerization

Phytophtora capsici es un patógeno que incide sobre cultivos de la familia de las solanáceas causando pérdidas económicas en cultivos de pimientos, tomates, berenjenas y cur-cubitáceas. En este trabajo evaluamos el efecto del quitosano de bajo grado de polimerización (QBP) sobre el crecimiento de P. capsici y sobre la regulación génica de este fitopatógeno a nivel transcripcional. A una concentración de 0,4mg/l de QBP se obtuvo un 88% de inhibición en el crecimiento; concentraciones superiores a 1,6 mg/l inhibieron el crecimiento en un 100%. Mediante ensayos de cambio en la movilidad electroforética de ácidos nucleicos se comprobó que el quitosano interactúa con el ADN y el ARN del hongo frente a concentraciones entre 2 y 4 mg/l de ADN y entre 0,5 y 3 mg/l de ARN. Además, se efectuó un análisis de despliegue diferencial de los productos de amplificación por RT-PCR de los ARN mensajeros de P. capsici obtenidos en presencia o ausencia de QBP; este mostró cambios en el perfil de expresión inducidos por el tratamiento con quitosano. El análisis bioinformático de las secuencias de los transcritos expresados diferencialmente sugiere que el QBP afectó la regulación génica de elementos involucrados en la síntesis de quitina y de proteínas de unión a hidratos de carbono.

Phytophthora blight of peppers, caused by oomycete Phytophthora capsici, currently causes economic losses in crops such as peppers, tomatoes, eggplant and cucurbits. In this work, we evaluated the effect of chitosan with low degree of polymerization (LDP) on growth and gene expression of P. capsici cultures. LDP chitosan inhibited 88% of P. capsici mycelial growth at concentrations up to 0,4 mg/l, whereas at concentrations higher than 1,6 mg/l it completely inhibit growth. Gel mobility shift assays demonstrated that chitosan interacts with DNA and RNA of the fungus at concentrations ranging from 2 to 4 mg/l for DNA and 0,5 to 3 mg/l for RNA. The differential display analysis of RT-PCR-amplification products of P. capsici messenger RNA revealed changes in gene expression profiles after the chitosan treatment. Bioinformatic analysis of sequences from selected differentially-expressed bands showed the gene regulation of elements involved in chitin synthesis and carbohydrate-binding proteins.

Desenvolvimento de biomateriais à base de quitosana: matriz de fibras eletrofiadas para regeneração tecidual e de hidrogel coacervado para entrega controlada de fármaco / Development of chitosan-based biomaterials: electrospun fiber matrix for tissue regeneration and coacervate hydrogel for controlled drug delivery

Os atuais avanços no desenvolvimento de biomateriais caminham para 2 áreas promissoras: a de regeneração tecidual e a de entrega controlada de fármacos. Assim, o presente estudo objetivou a síntese e caracterização de diferentes matrizes (fibras e hidrogel) à base de quitosana, a fim de se obter materiais biomiméticos para atuação em ambas áreas. Para regeneração, delineou-se a síntese de um arcabouço de fibras de quitosana com e sem cristais de nanohidroxiapatita onde, para isso, foram eletrofiadas soluções de quitosana (Ch) e de quitosana com nanohidroxiapatita (ChHa). Os espécimes de Ch apresentaram maior homogeneidade e maior diâmetro médio de fibras (690 ± 102 nm) que ChHa (358 ± 49 nm). No teste de viabilidade celular e na atividade da fosfatase alcalina não houve diferença estatística entre os grupos experimentais (Ch e ChHa), porém ambos diferiram do grupo controle (p < 0,001). Para o âmbito de liberação de fármacos, sintetizou-se, pela técnica de emulsão, dois tipos de hidrogéis: o primeiro, uma mistura da fase aquosa da solução de Ch (1 mL) e da solução de DNA (1 mL) (1:1) e o segundo, mistura da fase aquosa da solução de Ch (1 mL) e solução de Pectina (1 mL) (1:1). Ambas misturas foram realizadas em álcool benzílico (5 mL) com instrumento de dispersão de alto desempenho (31-34000 rpm min-1 por 5 min). Após a obtenção dos géis, 20mg de cada grupo foram imersos em uma solução aquosa de Própolis Verde (PV), na concentração de 70 µg/mL por 2 h e a cinética de liberação do PV foi analisada a 25 e 37oC em água e saliva artificial. Os espécimes obtidos foram liofilizados e depois caracterizados físicoquimicamente. A presença de pectina e de DNA foi comprovada por FTIR. A sorção de PV induziu uma modificação significativa da superfície do gel. Constatou-se uma separação de fases entre a quitosana e o DNA. A eficiência do encapsulamento não mudou significativamente entre 25 e 37oC. A cinética de liberação na água ou na saliva apresentou um mecanismo de duas etapas. E os resultados biológicos exibiram que esses materiais são aceitáveis no ambiente biológico. Assim, conclui-se que a matriz de fibras de quitosana com nHAp é capaz de promover diferenciação celular e a matriz de hidrogel de quitosana com Pectina ou DNA possui potencial para a liberação controlada de fármacos(AU)

Current advances in biomaterial development are moving to 2 promising areas: tissue regeneration and controlled drug delivery. Thus, the present study aimed the synthesis and characterization of different matrices (fibers and hydrogel) based on chitosan, in order to obtain biomimetic materials for performance in both areas. For regeneration, the synthesis of a scaffold of chitosan fibers with and without nanohydroxyapatite crystals was delineated, where chitosan (Ch) and chitosan with hydroxyapatite (ChHa) solutions were electrospun. Ch specimens presented higher homogeneity and larger mean fiber diameter (690±102nm) than ChHa (358 ± 49nm). In the cell viability test and alkaline phosphatase activity there was no statistical difference between the experimental groups. (Ch and ChHa), but both differed from the control group (p < 0,001). For the drug release scope, two types of hydrogels were synthesized by the emulsion technique: the first, a mixture of the aqueous phase of Ch solution (1 mL) and DNA solution (1 mL) (1:1) and the second, mixture of the aqueous phase of the Ch solution (1mL) and Pectin solution (1 mL) (1:1). Both mixtures were performed in benzyl alcohol (5 mL) with high performance dispersion instrument (31-34000 rpm min-1 for 5 min). After obtaining the gels, 20mg from each group were immersed in an aqueous solution of Propolis Green (PV), at a concentration of 70 µg/mL for 2 h and the release kinetics of PV were analyzed at 25 and 37oC in water and artificial saliva. The obtained specimens were lyophilized and then physically-chemically characterized. The presence of pectin and DNA was confirmed by FTIR. PV sorption induced a significant modification of the gel surface. A phase separation was found between chitosan and DNA. Encapsulation efficiency did not change significantly between 25 and 37oC. The release kinetics in water or saliva presented a two-step mechanism. And the biological results showed that these materials are acceptable in the biological environment. Thus, it is concluded that the nHAp chitosan fiber matrix is capable of promoting cell differentiation, whereas the chitosan hydrogel matrix with Pectin or DNA are potential biomaterials for controlled drug release(AU)

Safety of a formulation containing chitosan microparticles with chamomile: blind controlled clinical trial / Segurança de uma formulação contendo micropartículas de quitosana com camomila: ensaio clínico, mascarado e controlado / Seguridad de una formulación conteniendo micropartículas de quitosano con manzanilla: ensayo clínico, enmascarado y controlado

ABSTRACT Objective: to evaluate the safety of a topical formulation containing chamomile microparticles coated with chitosan in the skin of healthy participants. Method: phase I blind, controlled, non-randomized, single-dose clinical trial with control for skin, base formulation, and formulation with microparticles. The variables analyzed were irritation and hydration by the Wilcoxon and Kruskall-Wallis tests. Results: the study started with 35 participants with a mean age of 26.3 years. Of these, 30 (85.71%) were female, 29 (82.90%) were white skinned and 32 (91.40%) had no previous pathologies. One participant was removed from the study reporting erythema at the site of application, and four other participants for not attending the last evaluation. In the 30 participants who completed the study, the tested formulation did not cause erythema, peeling, burning, pruritus or pain; there was an improvement in cutaneous hydration in the site of application of the formulation with microparticles. In the evaluation of the barrier function, there was an increase in transepidermal water loss in all sites. Conclusion: the formulation with chamomile microparticles is safe for topical use, not causing irritation and improving skin hydration over four weeks of use. Its effects on barrier function need further investigation. No. RBR-3h78kz in the Brazilian Registry of Clinical Trials (ReBEC).

RESUMO Objetivo: avaliar a segurança de uma formulação tópica, contendo micropartículas de camomila revestidas com quitosana, na pele de participantes saudáveis. Método: ensaio clínico fase I, mascarado, controlado, não aleatorizado, de dose única, com controles da pele, da base da formulação e da formulação com micropartículas. As variáveis analisadas foram irritação e hidratação por meio dos testes de Wilcoxon e Kruskall-Wallis. Resultados: iniciaram o estudo 35 participantes com idade média de 26,3 anos. Destes, 30 (85,71%) eram do sexo feminino, 29 (82,90%) brancos e 32 (91,40%) sem patologias prévias. Um participante foi descontinuado por referir eritema no local de aplicação e quatro por não comparecerem à última avaliação. Nos 30 participantes que finalizaram o estudo, a formulação teste não causou eritema, descamação, ardor, prurido ou dor; houve melhora na hidratação cutânea no local de aplicação da formulação com as micropartículas. Na avaliação da função barreira houve aumento da perda transepidérmica de água em todos os locais. Conclusão: a formulação com micropartículas de camomila é segura para o uso tópico, não provocando irritação e melhorando a hidratação cutânea ao longo de quatro semanas de uso. Seus efeitos na função barreira devem ser melhor estudados. N° RBR-3h78kz no Registro Brasileiro de Ensaios Clínicos (ReBEC).

RESUMEN Objetivo: evaluar la seguridad de una formulación tópica, conteniendo micropartículas de manzanilla revestidas con quitosano, en la piel de participantes sanos. Método: ensayo clínico fase I, enmascarado, controlado, no aleatorizado, de dosis única, con controles de la piel, de la base de la formulación y de la formulación con micropartículas. Las variables analizadas fueron irritación e hidratación por medio de los tests de Wilcoxon y Kruskall-Wallis. Resultados: iniciaron el estudio 35 participantes con edad media de 26,3 años. De esos, 30 (85,71%) eran del sexo femenino, 29 (82,90%) blancos y 32 (91,40%) sin patologías previas. Un participante fue descontinuado por referir eritema en el local de aplicación y cuatro por no comparecer a la última evaluación. En los 30 participantes que finalizaron el estudio, la formulación test no causó eritema, descamación, ardor, prurito o dolor; hubo mejora en la hidratación cutánea en el local de aplicación de la formulación con las micropartículas. En la evaluación de la función barrera hubo aumento de la pérdida transepidérmica de agua en todos los locales. Conclusión: la formulación con micropartículas de manzanilla es segura para el uso tópico, no provocando irritación y mejorando la hidratación cutánea a lo largo de cuatro semanas de uso. Sus efectos en la función barrera deben ser mejor estudiados. N° RBR-3h78kz en el Registro Brasilero de Ensayos Clínicos (ReBEC).

Biochemical evaluation of chitosan in rats fed high fat-high carbohydrate- diet

This study was designed to evaluate the potential of chitosan at a dosage of 27, 180 and 270 mg/Kg b.w, which equivalent to 300, 2000 and 3000 mg/day human age recommended doses, respectively in rats fed high fat-high carbohydrate [HFHC]- diet for six weeks. The obtained results demonstrated that HFHC-fed rats displayed a significant increase in blood glucose, serum lipid profile, atherogenic index, ALT, AST, ALP, total bilirubin, malondialdehyde, urea, creatinine and uric acid compared to the normal control rats. However, the concomitant administration of chitosan with HFHC-diet for 8 weeks led to a dose-dependant improvement in these pathological changes. The low and medium doses of chitosan were exhibited mild to moderate effects. Only a dose of 270 mg chitosan /Kg b.w was able to maintain these changes at near normal levels and demonstrated its hypolipidaemic and hypoglycaemic activities

Time-dependent effects of chitosan on dentin structures

Complete debridement with smear layer removal are essential measures for achieving a successful outcome of root canal treatment. The aim of this study was to evaluate the effects of chitosan at different concentrations on the removal of the smear layer and on dentin structure after 3 and 5 min of application. Twelve recently extracted maxillary canine teeth were instrumented using the crown-down technique and irrigated with 1% sodium hypochlorite. The specimens were distributed according to the time and concentration of the final irrigating solution: G1: 0.1% chitosan for 3 min; G2: 0.2% chitosan for 3 min; G3: 0.37% chitosan for 3 min; G4: 0.1% chitosan for 5 min; G5: 0.2% chitosan for 5 min; G6: 0.37% chitosan for 5 min. All samples were prepared for SEM analysis. G1 exhibited removal of the smear layer, but not the smear plugs. G2 showed visible and open tubules with slight erosion of the peritubular dentin. Cleaning in G3 was similar to that in G2, however, the erosive effect was greater. There was expansion of the diameter of the tubules in G4; and in G5 and G6, there was severe erosion with deterioration of dentin surface. In conclusion, 0.2% chitosan for 3 min appeared to be efficient for removing the smear layer, causing little erosion of dentin.

Completo debridamento dos canais radiculares com a remoção da smear layer são medidas essenciais no sucesso do tratamento endodôntico. O objetivo deste estudo foi avaliar os efeitos da quitosana, em diferentes concentrações, na remoção da smear layer e na estrutura da dentina, após 3 e 5 min de aplicação. Doze dentes caninos superiores, recém extraídos, foram instrumentados pela técnica crown-down e irrigados com hipoclorito de sódio 1%. Os espécimes foram distribuídos em seis grupos conforme o tempo e a concentração da solução irrigante final: G1: quitosana 0,1% por 3 min; G2: quitosana 0,2% por 3 min; G3: quitosana 0,37% por 3 min; G4: quitosana 0,1% por 5 min; G5: quitosana 0,2% por 5 min; G6: quitosana 0,37% por 5 min. Todas as amostras foram preparadas para avaliação em MEV. Os resultados mostraram que o G1 apresentou remoção da smear layer, mas não da smear plug. O G2 mostrou túbulos visíveis e abertos com ligeira erosão da dentina peritubular. A limpeza no G3 foi semelhante à do G2, no entanto, o efeito erosivo foi maior. No G4 houve ampliação do diâmetro dos túbulos e no G5 e G6, severa erosão com deterioração da superfície dentinária. Concluiu-se que a quitosana 0,2% por 3 min foi eficiente na remoção da smear layer, ocasionando pequena erosão.

Assessment of Collagen-Induced Arthritis Using Cyanine 5.5 Conjugated with Hydrophobically Modified Glycol Chitosan Nanoparticles: Correlation with 18F-Fluorodeoxyglucose Positron Emission Tomography Data

OBJECTIVE: To evaluate the potential and correlation between near-infrared fluorescence (NIRF) imaging using cyanine 5.5 conjugated with hydrophobically modified glycol chitosan nanoparticles (HGC-Cy5.5) and 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) imaging of collagen-induced arthritis (CIA). MATERIALS AND METHODS: We used 10 CIA and 3 normal mice. Nine days after the injecting collagen twice, microPET imaging was performed 40 minutes after the intravenous injection of 9.3 MBq 18F-FDG in 200 microL PBS. One day later, NIRF imaging was performed two hours after the intravenous injection of HGC-cy5.5 (5 mg/kg). We assessed the correlation between these two modalities in the knees and ankles of CIA mice. RESULTS: The mean standardized uptake values of 18F-FDG for knees and ankles were 1.68 +/- 0.76 and 0.79 +/- 0.71, respectively, for CIA mice; and 0.57 +/- 0.17 and 0.54 +/- 0.20 respectively for control mice. From the NIRF images, the total photon counts per 30 mm2 for knees and ankles were 2.32 +/- 1.54 x 10(5) and 2.75 +/- 1.51 x 10(5), respectively, for CIA mice, and 1.22 +/- 0.27 x 10(5) and 0.88 +/- 0.24 x 10(5), respectively, for control mice. These two modalities showed a moderate correlation for knees (r = 0.604, p = 0.005) and ankles (r = 0.464, p = 0.039). Moreover, both HGC-Cy5.5 (p = 0.002) and 18F-FDG-PET (p = 0.005) imaging also showed statistically significant differences between CIA and normal mice. CONCLUSION: NIRF imaging using HGC-Cy5.5 was moderately correlated with 18F-FDG-PET imaging in the CIA model. As such, HGC-Cy5.5 imaging can be used for the early detection of rheumatoid arthritis.

Evaluation of chitosan gel with 1 percent silver sulfadiazine as an alternative for burn wound treatment in rats / Avaliação do gel de quitosana contendo sulfadiazina de prata 1 por cento como alternativa para o tratamento de queimaduras em ratos

PURPOSE: Evaluation of the rheological, biological and therapeutic properties of a new topical formulation consisting of chitosan gel containing 1 percent silver sulfadiazine, as an alternative for the treatment of burn wounds. METHODS: An experimental study was done with 21 Wistar rats divided into three groups. Group I was treated with chitosan gel without the antimicrobial, group II was treated with chitosan gel with 1 percent silver sulfadiazine and group III was treated with commercially available 1 percent silver sulfadiazine cream. RESULTS: Due to its pseudoplastic characteristic and good bioadhesiveness, the chitosan gels showed a satisfactory retention time over the wounds. No statistical difference was found in the amount of drug released from the chitosan gel and commercially available cream, as well as in the healing time among the groups. Wounds treated with chitosan gel with silver sulfadiazine showed a higher fibroblast production and a better angiogenesis than in the other groups, which are important parameters on the evolution of the healing process. CONCLUSION: The topical use of chitosan gel in association with silver sulfadiazine ameliorated the neovascularization and inflammatory reaction in burn wounds. This new formulation showed advantageous rheological properties and efficient release of the drug.

OBJETIVO: Avaliar as propriedades reológicas, biológicas e terapêuticas de uma nova formulação de uso tópico, a partir de um gel de quitosana, contendo sulfadiazina de prata a 1 por cento, no tratamento de queimaduras. MÉTODOS: Foi realizado estudo experimental com 21 ratos Wistar distribuídos em três grupos de sete animais. As queimaduras dos animais do grupo I foram tratadas com gel de quitosana sem antimicrobiano, o grupo II foi tratado com gel de quitosana contendo sulfadiazina de prata 1 por cento e o grupo III foi tratado com creme de sulfadiazina de prata 1 por cento, comumente utilizado no tratamento de queimados. RESULTADOS: Devido às características pseudoplásticas e à boa bioadesividade, os géis de quitosana apresentaram um tempo de retenção satisfatório sobre as feridas. A liberação da sulfadiazina de prata, bem como o tempo de cicatrização, não foram estatisticamente diferentes. Feridas tratadas com o gel de quitosana contendo sulfadiazina de prata apresentaram uma maior produção de fibroblastos e uma melhor angiogênese, comparando-se com os outros grupos, fatores que indicaram uma maior evolução no processo de cicatrização. CONCLUSÃO: O uso tópico do gel de quitosana com sulfadiazina de prata a 1 por cento melhorou a neovascularização e a reação inflamatória em queimaduras e essa nova formulação mostrou boas propriedades reológicas associadas a eficiente liberação do fármaco.

Imobilização de pepsina em membranas liofilizadas de quitosana e O-carboximetilquitosana / Pepsin immobilization into lyophilized chitosan and O-carboxymethilchitosan membranes

Enzimas são proteínas utilizadas em processos tecnológicos diversos. Estas enzimas dependendo do tipo e grau de pureza são geralmente caras. Comumente as enzimas exigem controle contínuo do processo no que se refere à temperatura, pH, agitação, entre outros, e após o uso são descartadas, o que torna o custo do processo mais elevado. Em decorrência disto, a imobilização de enzimas em suportes insolúveis e inertes, vem sendo proposta com resultados promissores de manutenção e até mesmo aumento da atividade enzimática, resistência mecânica, térmica e de pH, bem como por apresentar maior facilidade de remoção da enzima do sistema e possibilitar sua reutilização. Por causa disto, diferentes tipos de suportes vêem sendo estudados, dentre estes, os materiais poliméricos, tem recebido atenção especial. A quitosana é um polímero natural, biocompatível, biodegradável e atóxico. É obtida de fontes renováveis provenientes do descarte de cascas de crustáceos da indústria de alimentos, o que constitui um fator ambiental importante atualmente. Neste trabalho a enzima pepsina foi imobilizada em membranas liofilizadas de quitosana e O-carboximetilquitosana reticuladas ou não com glutaraldeído. A pepsina imobilizada na membrana de quitosana reticulada com glutaraldeído manteve sua atividade enzimática e o suporte apresentou propriedades físico-químicas de resistência a solubilização em pH ácido, o qual é necessário para atividade da pepsina. O processo de liofilização preservou a estrutura do suporte e não comprometeu a atividade enzimática. Demonstrando que o processo de liofilização é viável para secagem e incorporação de enzimas

Enzymes are proteins used in a wide variety of biotechnological processes. Commonly, enzymes require stringent conditions, such as a particular pH, temperature, stirring, etc. In chemical and biochemical reactions, purified enzymes can be rather costly and additionally, must be discarded after each use, which is still less economical. As a result of this, enzyme immobilization on insoluble and inert supports has been studied as a manner to overcome these problems and optimize enzymes use. Promising results of greater immobilized enzyme activity and stability over a broader range of pH and temperature have been reported. As well, immobilized enzymes can be easily removed from the system and reused. Various materials have been employed as enzymes supports, among then, the polymers have received special attention. Chitosan is a natural polymer that presents biocompatibility, biodegradability and nontoxicity. Chitosan is obtained from crustacean shell wastes discarded by the food industry, and recover this material constitutes an important environmental factor nowadays. In this work the enzyme pepsin was immobilized on freezedried chitosan and O-Carboxymethylchitosan membranes crosslinked or not with glutaraldehyde. Pepsin immobilized on chitosan membrane crosslinked with glutaraldehyde maintained its enzymatic activity and the polymer support provided physicochemical properties such resistance to dissolution in acid pH. Acid pH is required for pepsin activity. The freeze-drying process preserved the support structure and did not compromise the enzymatic activity. Demonstrating that, freeze drying process, is viable for drying and enzymes incorporation

NaCl plus chitosan as a dietary salt to prevent the development of hypertension in spontaneously hypertensive rats

The effect of NaCl plus 3% chitosan on the systolic blood pressure of spontaneously hypertensive rats (SHR) were evaluated and compared with NaCl plus KCl (NaCl, 49.36% + KCl 49.36%) and chitosan or NaCl treatment alone. In SHR, administration of NaCl plus chitosan (44 mM Na/day) for two months significantly decreased the systolic blood pressure greater than of NaCl plus KCl and NaCl alone. NaCl plus chitosan resulted, though not statistically significant, in decreased urinary Na+ excretion and decreased blood urea nitrogen levels. Urinary creatinine of NaCl plus chitosan was slightly decreased compared to 3 treated groups. Serum electrolytes levels, however, remained unchanged. The combination of NaCl and chitosan may be superior to the conventional use of NaCl plus KCl or NaCl alone in the prevention of hypertension. Even though these supplementary diets have demonstrated potential anti-hypertensive effects in the experimental animal model, further research is needed before any recommendations can be made.

La modulación del sistema inmune de mucosas con polisacáridos: Bases para una atractiva alternativa en terapia / Modulation of the mucosal immune system with polysaccharides: Basis for an attractive therapeutic alternative

El sistema inmune de mucosas del intestino presenta propiedades únicas: está expuesto a una gran variedad y cantidad de antígenos, desarrolla una actividad inmunológica permanente y mantiene un microambiente fisiológicamente desviado hacia respuestas anti-inflamatorias. Es capaz de distinguir y neutralizar agentes nocivos y reconocer antígenos inocuos, generando entonces un estado de no respuesta llamado tolerancia oral. Este fenómeno natural representa una forma fisiológica, segura e inocua de manipular las respuestas inmunes, para el tratamiento de enfermedades autoinmunes, inflamatorias o alérgicas. Aquellos compuestos que presenten la habilidad de favorecer la tolerancia permitirían optimizar el desarrollo de nuevos protocolos de inmunointervención. Quitosano (Q) es un polisacárido que abunda en la naturaleza con características fisicoquímicas y biológicas particulares: carece de toxicidad y alergenicidad, es biocompatible y biodegradable, presenta propiedades mucoadhesivas que favorecen el transporte y la absorción de proteínas a través del epitelio. Tiene actividad adyuvante, aumentando los niveles de IgA en la mucosa. Estas características lo convierten en un candidato ideal para la inmunointervención a nivel de mucosas. En este trabajo se describe el mecanismo de acción del Q luego de la administración oral, demostrando por primera vez que Q contribuye a mantener la homeostasis intestinal y a modular a nivel local y sistémico las respuestas inmunes hacia un antígeno proteico. Esta caracterización ayuda a comprender cómo participa un polisacárido en la fina regulación de las respuestas de mucosa y sugiere alternativas de manipulación que permitirán el desarrollo de terapias que requieran de microambientes anti-inflamatorios.

The mucosal immune system exhibits distinctive traits: it is permanently exposed to an overwhelming amount and variety of antigens; it maintains a continuous immune activity and it sustains a physiological environment biased to anti-inflammatory responses. Although it mounts efficient responses against pathogens, it reacts to innocuous antigens developing the oral tolerance state. Oral tolerance is a natural process that can be safely applied for the treatment of autoimmune, inflammatory or allergic diseases. Compounds able to promote the tolerance phenomenon can be used to optimize the development of alternative therapies. Chitosan (Q) is a natural and abundant polysaccharide with singular biological and physico-chemical properties that make it a good candidate to modulate the mucosal immunity: non toxic, biocompatible and biodegradable, strongly mucoadhesive favoring the transepithelial absorption of proteins and adjuvant, enhancing the levels of IgA to co-administered antigens. This work describes the Q activity mechanism early after its oral administration, for the first time showing, Q´s contribution to the intestinal homeostasis and also its modulation of the immune response to a protein antigen at local and systemic level. These studies will help understand how the intestinal regulatory activity occurs, and develop new therapeutic approaches to stimulate anti-inflammatory environments at mucosal level.

A Pilot Study of Trans-Arterial Injection of 166Holmium-Chitosan Complex for Treatment of Small Hepatocellular Carcinoma

Percutaneous approaches, such as percutaneous ethanol injection and radiofrequency ablation, have been most widely used for hepatocellular carcinoma patients who were not eligible for surgery. New technologies to improve the efficacy are currently needed. 166Holmium is a neutron activated radionuclide, and has several beneficial radiophysical characteristics for internal radiation therapy. 166Holmium-Chitosan complex, in which chitosan is chelated with 166Holmium, was developed as a radiopharmaceutical for cancer therapy. We have conducted a pilot study to evaluate the clinical efficacy of transarterial administration of 166Holmium-Chitosan complex in patients with a single and small (< 3 cm) hepatocellular carcinoma. 166Holmium-Chitosan complex, at a dose of 20 mCi per cm of tumor mass-diameter, was administered through the artery that directly fed the tumor. Twelve patients were treated with a median follow-up duration of 26 (range: 12-61) months. The tumor diameter ranged between 1.5 and 2.5 cm. Ten patients (83%) had complete response and two (17%) had partial response. The median complete response duration was not reached. The median AFP level declined from 83.8 to 8.3 ng/mL within 2 months after treatment. No grade III/IV toxicity was observed. Grade I and II toxicities were observed in four patients (2 abdominal pain, 1 fever, and 1 AST/ALT elevation). No toxic death occurred. This preliminary study shows a promising and durable complete response rate with an acceptable safety profile. Further studies with greater accrual of patients are warranted.