1
|
Marques AP, Reis RL, Hunt JA. The biocompatibility of novel starch-based polymers and composites: in vitro studies. Biomaterials 2002; 23:1471-8. [PMID: 11829443 DOI: 10.1016/s0142-9612(01)00272-1] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Studies with biodegradable starch-based polymers have recently demonstrated that these materials have a range of properties. which make them suitable for use in several biomedical applications, ranging from bone plates and screws to drug delivery carriers and tissue engineering scaffolds. The aim of this study was to screen the cytotoxicity and evaluate starch-based polymers and composites as potential biomaterials. The biocompatibility of two different blends of corn-starch, starch ethylene vinyl alcohol (SEVA-C) and starch cellulose acetate (SCA) and their respective composites with hydroxyapatite (HA) was assessed by cytotoxicity and cell adhesion tests. The MTT assay was performed with the extracts of the materials in order to evaluate the short-term effect of the degradation products. The cell morphology of L929 mouse fibroblast cell line was also analysed after direct contact with polymers and composites for different time periods and the number of cells adhered to the surface of the polymers was determined by quantification of the cytosolic lactate dehydrogenase (LDH) activity. Both types of starch-based polymers exhibit a cytocompatibility that might allow for their use as biomaterials. SEVA-C blends were found to be the less cytotoxic for the tested cell line, although cells adhere better to SCA surface. The cytotoxicity test also revealed that SCA and SEVA-C composites have a similar response to the one obtained for SCA polymer. Scanning electron microscopy (SEM) analysis showed that cells were much more spread on the SCA polymer and LDH measurements showed a higher number of cells on this surface.
Collapse
|
|
23 |
178 |
2
|
Schmader KE, Oxman MN, Levin MJ, Johnson G, Zhang JH, Betts R, Morrison VA, Gelb L, Guatelli JC, Harbecke R, Pachucki C, Keay S, Menzies B, Griffin MR, Kauffman C, Marques A, Toney J, Keller PM, Li X, Chan ISF, Annunziato P. Persistence of the efficacy of zoster vaccine in the shingles prevention study and the short-term persistence substudy. Clin Infect Dis 2012; 55:1320-8. [PMID: 22828595 DOI: 10.1093/cid/cis638] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The Shingles Prevention Study (SPS; Department of Veterans Affairs Cooperative Study 403) demonstrated that zoster vaccine was efficacious through 4 years after vaccination. The Short-Term Persistence Substudy (STPS) was initiated after the SPS to further assess the persistence of vaccine efficacy. METHODS The STPS re-enrolled 7320 vaccine and 6950 placebo recipients from the 38 546-subject SPS population. Methods of surveillance, case determination, and follow-up were analogous to those in the SPS. Vaccine efficacy for herpes zoster (HZ) burden of illness, incidence of postherpetic neuralgia (PHN), and incidence of HZ were assessed for the STPS population, for the combined SPS and STPS populations, and for each year through year 7 after vaccination. RESULTS In the STPS as compared to the SPS, vaccine efficacy for HZ burden of illness decreased from 61.1% to 50.1%, vaccine efficacy for the incidence of PHN decreased from 66.5% to 60.1%, and vaccine efficacy for the incidence of HZ decreased from 51.3% to 39.6%, although the differences were not statistically significant. Analysis of vaccine efficacy in each year after vaccination for all 3 outcomes showed a decrease in vaccine efficacy after year 1, with a further decline thereafter. Vaccine efficacy was statistically significant for the incidence of HZ and the HZ burden of illness through year 5. CONCLUSIONS Vaccine efficacy for each study outcome was lower in the STPS than in the SPS. There is evidence of the persistence of vaccine efficacy through year 5 after vaccination but, vaccine efficacy is uncertain beyond that point.
Collapse
|
Research Support, U.S. Gov't, Non-P.H.S. |
13 |
175 |
3
|
Álvarez-Muñoz D, Rodríguez-Mozaz S, Maulvault AL, Tediosi A, Fernández-Tejedor M, Van den Heuvel F, Kotterman M, Marques A, Barceló D. Occurrence of pharmaceuticals and endocrine disrupting compounds in macroalgaes, bivalves, and fish from coastal areas in Europe. ENVIRONMENTAL RESEARCH 2015; 143:56-64. [PMID: 26409498 DOI: 10.1016/j.envres.2015.09.018] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 06/30/2015] [Accepted: 09/14/2015] [Indexed: 06/05/2023]
Abstract
The occurrence and levels of PhACs, Endocrine Disrupting and related Compounds (EDCs) in seafood from potential contaminated areas in Europe has been studied. Macroalgae (Saccharina latissima and Laminaria digitata), bivalves (Mytilus galloprovincialis, Mytilus spp., Chamalea gallina and Crassostrea gigas) and fish (Liza aurata and Platichthys flesus) from Portugal, Spain, Italy, Netherlands, and Norway were analysed following 4 different analytical protocols depending on the organism and target group of contaminants. The results revealed the presence of 4 pharmaceutical compounds in macroalgae samples, 16 in bivalves and 10 in fish. To the best of our knowledge, this is the first time that PhACs have been detected in marine fish and in macroalgae. Besides, this is also the first time that dimetridazole, hydrochlorothiazide and tamsulosin have been detected in biota samples. The highest levels of PhACs corresponded to the psychiatric drug velanfaxine (up to 36.1 ng/g dry weight (dw)) and the antibiotic azithromycin (up to 13.3 ng/g dw) in bivalves from the Po delta (Italy). EDCs were not detected in macroalgae samples, however, the analysis revealed the presence of 10 EDCs in bivalves and 8 in fish. The highest levels corresponded to the organophosphorus flame retardant tris(2-butoxyethyl)phosphate (TBEP) reaching up to 98.4 ng/g dw in mullet fish from the Tagus estuary. Bivalves, in particular mussels, have shown to be good bioindicator organisms for PhACs and fish for EDCs. Taking into consideration the concentrations and frequencies of detection of PhACs and EDCs in the seafood samples analysed, a list of candidates' compounds for priorization in future studies has been proposed.
Collapse
|
|
10 |
164 |
4
|
Hemmer B, Gran B, Zhao Y, Marques A, Pascal J, Tzou A, Kondo T, Cortese I, Bielekova B, Straus SE, McFarland HF, Houghten R, Simon R, Pinilla C, Martin R. Identification of candidate T-cell epitopes and molecular mimics in chronic Lyme disease. Nat Med 1999; 5:1375-82. [PMID: 10581079 DOI: 10.1038/70946] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Elucidating the cellular immune response to infectious agents is a prerequisite for understanding disease pathogenesis and designing effective vaccines. In the identification of microbial T-cell epitopes, the availability of purified or recombinant bacterial proteins has been a chief limiting factor. In chronic infectious diseases such as Lyme disease, immune-mediated damage may add to the effects of direct infection by means of molecular mimicry to tissue autoantigens. Here, we describe a new method to effectively identify both microbial epitopes and candidate autoantigens. The approach combines data acquisition by positional scanning peptide combinatorial libraries and biometric data analysis by generation of scoring matrices. In a patient with chronic neuroborreliosis, we show that this strategy leads to the identification of potentially relevant T-cell targets derived from both Borrelia burgdorferi and the host. We also found that the antigen specificity of a single T-cell clone can be degenerate and yet the clone can preferentially recognize different peptides derived from the same organism, thus demonstrating that flexibility in T-cell recognition does not preclude specificity. This approach has potential applications in the identification of ligands in infectious diseases, tumors and autoimmune diseases.
Collapse
|
Case Reports |
26 |
141 |
5
|
Marques A, Martins IS, Kastner T, Plutzar C, Theurl MC, Eisenmenger N, Huijbregts MAJ, Wood R, Stadler K, Bruckner M, Canelas J, Hilbers JP, Tukker A, Erb K, Pereira HM. Increasing impacts of land use on biodiversity and carbon sequestration driven by population and economic growth. Nat Ecol Evol 2019; 3:628-637. [PMID: 30833755 PMCID: PMC6443044 DOI: 10.1038/s41559-019-0824-3] [Citation(s) in RCA: 130] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 01/23/2019] [Indexed: 11/09/2022]
Abstract
Biodiversity and ecosystem service losses driven by land-use change are expected to intensify as a growing and more affluent global population requires more agricultural and forestry products, and teleconnections in the global economy lead to increasing remote environmental responsibility. By combining global biophysical and economic models, we show that, between the years 2000 and 2011, overall population and economic growth resulted in increasing total impacts on bird diversity and carbon sequestration globally, despite a reduction of land-use impacts per unit of gross domestic product (GDP). The exceptions were North America and Western Europe, where there was a reduction of forestry and agriculture impacts on nature accentuated by the 2007-2008 financial crisis. Biodiversity losses occurred predominantly in Central and Southern America, Africa and Asia with international trade an important and growing driver. In 2011, 33% of Central and Southern America and 26% of Africa's biodiversity impacts were driven by consumption in other world regions. Overall, cattle farming is the major driver of biodiversity loss, but oil seed production showed the largest increases in biodiversity impacts. Forestry activities exerted the highest impact on carbon sequestration, and also showed the largest increase in the 2000-2011 period. Our results suggest that to address the biodiversity crisis, governments should take an equitable approach recognizing remote responsibility, and promote a shift of economic development towards activities with low biodiversity impacts.
Collapse
|
Research Support, Non-U.S. Gov't |
6 |
130 |
6
|
Rieb JT, Chaplin-Kramer R, Daily GC, Armsworth PR, Böhning-Gaese K, Bonn A, Cumming GS, Eigenbrod F, Grimm V, Jackson BM, Marques A, Pattanayak SK, Pereira HM, Peterson GD, Ricketts TH, Robinson BE, Schröter M, Schulte LA, Seppelt R, Turner MG, Bennett EM. When, Where, and How Nature Matters for Ecosystem Services: Challenges for the Next Generation of Ecosystem Service Models. Bioscience 2017. [DOI: 10.1093/biosci/bix075] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
|
8 |
92 |
7
|
Vanham D, Leip A, Galli A, Kastner T, Bruckner M, Uwizeye A, van Dijk K, Ercin E, Dalin C, Brandão M, Bastianoni S, Fang K, Leach A, Chapagain A, Van der Velde M, Sala S, Pant R, Mancini L, Monforti-Ferrario F, Carmona-Garcia G, Marques A, Weiss F, Hoekstra AY. Environmental footprint family to address local to planetary sustainability and deliver on the SDGs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 693:133642. [PMID: 31635013 PMCID: PMC6853168 DOI: 10.1016/j.scitotenv.2019.133642] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/26/2019] [Accepted: 07/26/2019] [Indexed: 05/20/2023]
Abstract
The number of publications on environmental footprint indicators has been growing rapidly, but with limited efforts to integrate different footprints into a coherent framework. Such integration is important for comprehensive understanding of environmental issues, policy formulation and assessment of trade-offs between different environmental concerns. Here, we systematize published footprint studies and define a family of footprints that can be used for the assessment of environmental sustainability. We identify overlaps between different footprints and analyse how they relate to the nine planetary boundaries and visualize the crucial information they provide for local and planetary sustainability. In addition, we assess how the footprint family delivers on measuring progress towards Sustainable Development Goals (SDGs), considering its ability to quantify environmental pressures along the supply chain and relating them to the water-energy-food-ecosystem (WEFE) nexus and ecosystem services. We argue that the footprint family is a flexible framework where particular members can be included or excluded according to the context or area of concern. Our paper is based upon a recent workshop bringing together global leading experts on existing environmental footprint indicators.
Collapse
|
Review |
6 |
90 |
8
|
Dinis-Oliveira RJ, Carvalho F, Duarte JA, Remião F, Marques A, Santos A, Magalhães T. Collection of biological samples in forensic toxicology. Toxicol Mech Methods 2010; 20:363-414. [PMID: 20615091 DOI: 10.3109/15376516.2010.497976] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Forensic toxicology is the study and practice of the application of toxicology to the purposes of the law. The relevance of any finding is determined, in the first instance, by the nature and integrity of the specimen(s) submitted for analysis. This means that there are several specific challenges to select and collect specimens for ante-mortem and post-mortem toxicology investigation. Post-mortem specimens may be numerous and can endow some special difficulties compared to clinical specimens, namely those resulting from autolytic and putrefactive changes. Storage stability is also an important issue to be considered during the pre-analytic phase, since its consideration should facilitate the assessment of sample quality and the analytical result obtained from that sample. The knowledge on degradation mechanisms and methods to increase storage stability may enable the forensic toxicologist to circumvent possible difficulties. Therefore, advantages and limitations of specimen preservation procedures are thoroughfully discussed in this review. Presently, harmonized protocols for sampling in suspected intoxications would have obvious utility. In the present article an overview is given on sampling procedures for routinely collected specimens as well as on alternative specimens that may provide additional information on the route and timing of exposure to a specific xenobiotic. Last, but not least, a discussion on possible bias that can influence the interpretation of toxicological results is provided. This comprehensive review article is intented as a significant help for forensic toxicologists to accomplish their frequently overwhelming mission.
Collapse
|
Review |
15 |
89 |
9
|
Abstract
OBJECTIVES To provide a systematic review of the effectiveness of home telemonitoring to reduce healthcare utilisation and improve health-related outcomes of patients with chronic obstructive pulmonary disease (COPD). METHODS An electronic literature search in Medline, Embase, B-on and Web of Science was conducted from June to August 2012 and updated until July 2013, using the following keywords: [tele(-)monitoring or tele(-)health or tele(-)homecare or tele(-)care or tele-home health or home monitoring] and [Chronic Obstructive Pulmonary Disease or COPD]. Randomised and non-randomised controlled trials evaluating home telemonitoring interventions in COPD were included. A meta-analysis using risk ratio (RR) and standardised mean difference (SMD) was conducted for healthcare utilisation (hospitalisations, length of stay, emergency department visits) and associated costs, and health-related outcomes [mortality, exacerbations and health-related quality of life (HRQOL)]. RESULTS Nine articles were included. Significant differences were found for hospitalisation rates (RR = 0.72; 95% CI = 0.53-0.98; p = 0.034); however, no differences in the other healthcare utilisation outcomes were observed. There was a trend to reduced healthcare costs in the telemonitoring group. In two studies, this intervention was associated with a reduced number of exacerbations (p < 0.05) and a significant increase in HRQOL (SMD = -0.53; 95% CI = -0.97- -0.09; p = 0.019). DISCUSSION AND CONCLUSIONS Home telemonitoring appears to have a positive effect in reducing respiratory exacerbations and hospitalisations and improving quality of life. However, the evidence of its benefits is still limited and further research is needed to assess the effectiveness of home telemonitoring in COPD management, as there are still few studies in this area.
Collapse
|
Meta-Analysis |
11 |
88 |
10
|
Cerqueira MT, da Silva LP, Santos TC, Pirraco RP, Correlo VM, Reis RL, Marques AP. Gellan gum-hyaluronic acid spongy-like hydrogels and cells from adipose tissue synergize promoting neoskin vascularization. ACS APPLIED MATERIALS & INTERFACES 2014; 6:19668-19679. [PMID: 25361388 DOI: 10.1021/am504520j] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Currently available substitutes for skin wound healing often result in the formation of nonfunctional neotissue. Thus, urgent care is still needed to promote an effective and complete regeneration. To meet this need, we proposed the assembling of a construct that takes advantage of cell-adhesive gellan gum-hyaluronic acid (GG-HA) spongy-like hydrogels and a powerful cell-machinery obtained from adipose tissue, human adipose stem cells (hASCs), and microvascular endothelial cells (hAMECs). In addition to a cell-adhesive character, GG-HA spongy-like hydrogels overpass limitations of traditional hydrogels, such as reduced physical stability and limited manipulation, due to improved microstructural arrangement characterized by pore wall thickening and increased mean pore size. The proposed constructs combining cellular mediators of the healing process within the spongy-like hydrogels that intend to recapitulate skin matrix aim to promote neoskin vascularization. Stable and off-the-shelf dried GG-HA polymeric networks, rapidly rehydrated at the time of cell seeding then depicting features of both sponges and hydrogels, enabled the natural cell entrapment/encapsulation and attachment supported by cell-polymer interactions. Upon transplantation into mice full-thickness excisional wounds, GG-HA spongy-like hydrogels absorbed the early inflammatory cell infiltrate and led to the formation of a dense granulation tissue. Consequently, spongy-like hydrogel degradation was observed, and progressive wound closure, re-epithelialization, and matrix remodelling was improved in relation to the control condition. More importantly, GG-HA spongy-like hydrogels promoted a superior neovascularization, which was enhanced in the presence of human hAMECs, also found in the formed neovessels. These observations highlight the successful integration of a valuable matrix and prevascularization cues to target angiogenesis/neovascularization in skin full-thickness excisional wounds.
Collapse
|
|
11 |
80 |
11
|
Cunha SC, Trabalón L, Jacobs S, Castro M, Fernandez-Tejedor M, Granby K, Verbeke W, Kwadijk C, Ferrari F, Robbens J, Sioen I, Pocurull E, Marques A, Fernandes JO, Domingo JL. UV-filters and musk fragrances in seafood commercialized in Europe Union: Occurrence, risk and exposure assessment. ENVIRONMENTAL RESEARCH 2018; 161:399-408. [PMID: 29197758 DOI: 10.1016/j.envres.2017.11.015] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/05/2017] [Accepted: 11/09/2017] [Indexed: 05/24/2023]
Abstract
In the framework of the FP7 ECsafeSeafood project, 62 seafood samples commercialized in Europe Union from several representative species - mackerel, tuna, salmon, seabream, cod, monkfish, crab, shrimp, octopus, perch and plaice - were analysed for residues of 21 personal care products (PCPs), including 11 UV-filters (UV-Fs) and 10 musk fragrances (musks). PCPs analysis were performed by Quick, Easy, Cheap, Effective Rugged, Safe (QuEChERS), combined with liquid-liquid extraction (LLE) or dispersive solid-phase extraction (dSPE), followed by gas chromatography-tandem mass spectrometry (GC-MS/MS). The results showed the presence in a wide range of samples of nine out of eleven UV-Fs compounds analysed, namely 2-ethylhexyl salicylate (EHS), 2-ethylhexyl,4-methoxycinnamate (EHMC), 4-methylbenzylidenecamphor (4-MBC), benzophenone-1 (BP1), benzophenone-3 (BP3), isoamyl-4-methoxycinnamate (IMC), 2,2'-dihydroxy-4,4'-dimethoxybenzophenone (DHMB), homosalate (HS), and octocrylene (OC), whereas galaxolide (HHCB), galaxolide lactone (HHCB-lactone), and tonalide (AHTN) were the most found musks. The potential risks to human health associated with the exposure to eight of the more prevalent PCPs - EHS, EHMC, 4-MBC, BP1, BP3, IMC, HHCB, and AHTN - through seafood consumption were assessed for consumers from five European countries (Belgium, Ireland, Italy, Portugal and Spain). Results showed that the human exposure to UV-Fs and musks estimated from the concentration values found in seafood and the daily consumption of concerned seafood species, were far below toxicological reference values.
Collapse
|
|
7 |
78 |
12
|
Camargo LM, dal Colletto GM, Ferreira MU, Gurgel SDM, Escobar AL, Marques A, Krieger H, Camargo EP, da Silva LH. Hypoendemic malaria in Rondonia (Brazil, western Amazon region): seasonal variation and risk groups in an urban locality. Am J Trop Med Hyg 1996; 55:32-8. [PMID: 8702019 DOI: 10.4269/ajtmh.1996.55.32] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A longitudinal epidemiologic survey (1989-1991) plus a cross-sectional parasitologic, clinical, and sociodemographic survey (July-October 1990) were conducted in Candeias do Jamary, a village with approximately 7,000 inhabitants in Rondonia, Brazil. Analysis of the results revealed hypoendemic malaria with a complex epidemiology. Plasmodium vivax predominated over P. falciparum infections while infections with P. malariae were absent. Malaria is present throughout the year but was clearly seasonal with epidemic outbreaks in the dry season from June to August. Malaria prevalence was lower in children less than 10 years of age and significantly higher in young adult males, which represent the high-risk group. The incidence of locally acquired infections (autochthonous cases) was significantly lower in the rainy season as compared with the dry season. This is not true with respect to heterotochthonous (imported) malaria cases, that is, malaria acquired elsewhere by Candeias residents, most of whom are male adults working outside the town. In both cases, however, the age and sex distribution of prevalence and its relationship with occupational activities indicate a predominance of outdoor transmission. The results of the cross-sectional survey are in agreement with those of the longitudinal passive survey and, in addition, disclose the absence of asymptomatic infection.
Collapse
|
|
29 |
76 |
13
|
Schröter M, Albert C, Marques A, Tobon W, Lavorel S, Maes J, Brown C, Klotz S, Bonn A. National Ecosystem Assessments in Europe: A Review. Bioscience 2016; 66:813-828. [PMID: 28533561 PMCID: PMC5421311 DOI: 10.1093/biosci/biw101] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
National ecosystem assessments form an essential knowledge base for safeguarding biodiversity and ecosystem services. We analyze eight European (sub-)national ecosystem assessments (Portugal, United Kingdom, Spain, Norway, Flanders, Netherlands, Finland, and Germany) and compare their objectives, political context, methods, and operationalization. We observed remarkable differences in breadth of the assessment, methods employed, variety of services considered, policy mandates, and funding mechanisms. Biodiversity and ecosystem services are mainly assessed independently, with biodiversity conceptualized as underpinning services, as a source of conflict with services, or as a service in itself. Recommendations derived from our analysis for future ecosystem assessments include the needs to improve the common evidence base, to advance the mapping of services, to consider international flows of services, and to connect more strongly to policy questions. Although the context specificity of national ecosystem assessments is acknowledged as important, a greater harmonization across assessments could help to better inform common European policies and future pan-regional assessments.
Collapse
|
Journal Article |
9 |
76 |
14
|
Cerqueira MT, Pirraco RP, Marques AP. Stem Cells in Skin Wound Healing: Are We There Yet? Adv Wound Care (New Rochelle) 2016; 5:164-175. [PMID: 27076994 PMCID: PMC4817598 DOI: 10.1089/wound.2014.0607] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 03/27/2015] [Indexed: 12/17/2022] Open
Abstract
Significance: Cutaneous wound healing is a serious problem worldwide that affects patients with various wound types, resulting from burns, traumatic injuries, and diabetes. Despite the wide range of clinically available skin substitutes and the different therapeutic alternatives, delayed healing and scarring are often observed. Recent Advances: Stem cells have arisen as powerful tools to improve skin wound healing, due to features such as effective secretome, self-renewal, low immunogenicity, and differentiation capacity. They represent potentially readily available biological material that can particularly target distinct wound-healing phases. In this context, mesenchymal stem cells have been shown to promote cell migration, angiogenesis, and a possible regenerative rather than fibrotic microenvironment at the wound site, mainly through paracrine signaling with the surrounding cells/tissues. Critical Issues: Despite the current insights, there are still major hurdles to be overcome to achieve effective therapeutic effects. Limited engraftment and survival at the wound site are still major concerns, and alternative approaches to maximize stem cell potential are a major demand. Future Directions: This review emphasizes two main strategies that have been explored in this context. These comprise the exploration of hypoxic conditions to modulate stem cell secretome, and the use of adipose tissue stromal vascular fraction as a source of multiple cells, including stem cells and factors requiring minimal manipulation. Nonetheless, the attainment of these approaches to target successfully skin regeneration will be only evident after a significant number of in vivo works in relevant pre-clinical models.
Collapse
|
Review |
9 |
75 |
15
|
Gutthann F, Egert M, Marques A, Appel J. Inhibition of respiration and nitrate assimilation enhances photohydrogen evolution under low oxygen concentrations in Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:161-9. [PMID: 17274945 DOI: 10.1016/j.bbabio.2006.12.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 12/09/2006] [Accepted: 12/12/2006] [Indexed: 10/23/2022]
Abstract
In cyanobacterial membranes photosynthetic light reaction and respiration are intertwined. It was shown that the single hydrogenase of Synechocystis sp. PCC 6803 is connected to the light reaction. We conducted measurements of hydrogenase activity, fermentative hydrogen evolution and photohydrogen production of deletion mutants of respiratory electron transport complexes. All single, double and triple mutants of the three terminal respiratory oxidases and the ndhB-mutant without a functional complex I were studied. After activating the hydrogenase by applying anaerobic conditions in the dark hydrogen production was measured at the onset of light. Under these conditions respiratory capacity and amount of photohydrogen produced were found to be inversely correlated. Especially the absence of the quinol oxidase induced an increased hydrogenase activity and an increased production of hydrogen in the light compared to wild type cells. Our results support that the hydrogenase as well as the quinol oxidase function as electron valves under low oxygen concentrations. When the activities of photosystem II and I (PSII and PSI) are not in equilibrium or in case that the light reaction is working at a higher pace than the dark reaction, the hydrogenase is necessary to prevent an acceptor side limitation of PSI, and the quinol oxidase to prevent an overreduction of the plastoquinone pool (acceptor side of PSII). Besides oxygen, nitrate assimilation was found to be an important electron sink. Inhibition of nitrate reductase resulted in an increased fermentative hydrogen production as well as higher amounts of photohydrogen.
Collapse
|
|
18 |
69 |
16
|
da Silva LP, Santos TC, Rodrigues DB, Pirraco RP, Cerqueira MT, Reis RL, Correlo VM, Marques AP. Stem Cell-Containing Hyaluronic Acid-Based Spongy Hydrogels for Integrated Diabetic Wound Healing. J Invest Dermatol 2017; 137:1541-1551. [PMID: 28259681 DOI: 10.1016/j.jid.2017.02.976] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 01/31/2017] [Accepted: 02/06/2017] [Indexed: 12/27/2022]
Abstract
The detailed pathophysiology of diabetic foot ulcers is yet to be established and improved treatments are still required. We propose a strategy that directs inflammation, neovascularization, and neoinnervation of diabetic wounds. Aiming to potentiate a relevant secretome for nerve regeneration, stem cells were precultured in hyaluronic acid-based spongy hydrogels under neurogenic/standard media before transplantation into diabetic mice full-thickness wounds. Acellular spongy hydrogels and empty wounds were used as controls. Re-epithelialization was attained 4 weeks after transplantation independently of the test groups, whereas a thicker and more differentiated epidermis was observed for the cellular spongy hydrogels. A switch from the inflammatory to the proliferative phase of wound healing was revealed for all the experimental groups 2 weeks after injury, but a significantly higher M2(CD163+)/M1(CD86+) subtype ratio was observed in the neurogenic preconditioned group that also failed to promote neoinnervation. A higher number of intraepidermal nerve fibers were observed for the unconditioned group probably due to a more controlled transition from the inflammatory to the proliferative phase. Overall, stem cell-containing spongy hydrogels represent a promising approach to enhance diabetic wound healing by positively impacting re-epithelialization and by modulating the inflammatory response to promote a successful neoinnervation.
Collapse
|
Research Support, Non-U.S. Gov't |
8 |
64 |
17
|
Hespanhol V, Queiroga H, Magalhães A, Santos AR, Coelho M, Marques A. Survival predictors in advanced non-small cell lung cancer. Lung Cancer 1995; 13:253-67. [PMID: 8719065 DOI: 10.1016/0169-5002(95)00497-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The authors studied the influence on survival of 21 clinical, anatomical, haematological and biochemical factors evaluated, at diagnosis, of 411 patients (pts) with advanced Non Small Cell Lung Cancer (NSCLC) followed in our department between 1984 and 1990. Most of the patients were male (347--84.4%) and only 64 (15.6%) were females. Median age was 62 years, but was slightly higher in females. Only 34 patients were aged under 45 years. Squamous cell carcinoma (215 pts--52%) and adenocarcinoma (152 pts--37%) were the most frequent histologic types. Performance status was poor--only 103 (25%) continued active; 120 (29%) spent at least half of the time in bed; 188 (46%) were severely limited. After staging, 179 (44%) presented locally advanced disease (stage IIIB) and 232 (56%) metastatic dissemination (stage IV). Therapy was defined by the oncologic group according to individual characteristics and based on clinical grounds. Anti-neoplastic therapy was performed in 225 (55%), chemotherapy alone in 121 (30%), radiation therapy alone in 67 (16%), and sequential combined treatment (chemotherapy and thoracic radiation) in 37 (9%). Until 1987, the main chemotherapy regimen was MACC (Metrotrexate + Adriamycine + Cyclophosphamide + Lomustin), afterwards VP(M) (Cisplatin + Vimblastin + Mitomycine). Radiation therapy was performed using Co60, 2 Gy/day, 5 days a week, for 4 weeks (approximately 45 Gy total). The response rate was poor--four complete responses (2%), 42 (19%) partial responses. The overall median survival was 4.3 months and only 5% of patients were alive after 18 months of follow up. Prognostic importance of each characteristic studied was initially done by unifactorial analysis, followed by multifactorial analysis according to two methods: Cox proportional hazards model and recursive partitioning amalgamation--RECPAM. Regardless of the method used, the main determinants of survival were found to be performance status (Zubrod), weight loss and serum albumin. Other factors such as the staging (presence or absence of metastasis), lymphocytes, lactic dehydrogenase, and hoarseness were also significant. It is noteworthy that age and histological type were irrelevant; sex and hoarseness only proved important when integrated within a multifactorial model. The overall prognostic evaluation and therapeutic decision of advanced NSCLC patients could be improved by combining the prognostic value of TNM with that of performance status, weight loss and serum albumin. These prognostic guidelines must be taken into account when designing new clinical trials.
Collapse
|
Comparative Study |
30 |
57 |
18
|
Fantini ML, Macedo L, Zibetti M, Sarchioto M, Vidal T, Pereira B, Marques A, Debilly B, Derost P, Ulla M, Vitello N, Cicolin A, Lopiano L, Durif F. Increased risk of impulse control symptoms in Parkinson's disease with REM sleep behaviour disorder. J Neurol Neurosurg Psychiatry 2015; 86:174-9. [PMID: 25006210 DOI: 10.1136/jnnp-2014-307904] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE To assess the frequency of symptoms of impulse control disorders (ICD, namely pathological gambling, compulsive sexual behaviour, compulsive eating and compulsive shopping) and related behaviours (hobbyism, punding, walkabout and dopamine dysregulation syndrome) in patients with Parkinson's disease (PD) with and without probable rapid eye movement, sleep behaviour disorder (pRBD). METHODS Two hundred and sixteen consecutive PD patients, attending two university-based movement disorders clinics, were screened for p-RBD using the RBD Single Question and the RBD Screening Questionnaire (RBDSQ). Current ICDs and related behaviours symptoms were assessed with the Questionnaire for Impulsive-Compulsive Disorders in PD (QUIP)-short form. RESULTS PD-pRBD patients (n=106/216;49%) had a longer PD duration, a higher Hoehn & Yahr score, a greater levodopa-equivalent daily dose (LEDD), but no difference in dopamine agonist use, compared to PD-without pRBD. A higher proportion of one or more current ICDs and related behaviours symptoms was reported in PD-pRBD compared to PD-without RBD (53% vs28%; p=0.0002). In a multivariate regression analysis accounting for gender, age of onset, PD duration, PD severity, depression score and total and dopaminergic agonist-LEDD, RBD was associated to a relative risk of 1.84 for any ICD or related behaviours symptoms (p=0.01), and to a risk of 2.59 for any ICD symptoms only (p=0.001). Furthermore, PD-pRBD had a more than fourfold risk for symptoms of pathological gambling (relative risk (RR): 4.87; p=0.049) compared to PD-without pRBD. CONCLUSIONS The present study indicates that RBD is associated with an increased risk of developing symptoms of ICDs in PD. Identifying RBD in PD may help clinicians to choose the best therapeutic strategy. TRIAL REGISTRATION AU1023 Institutional Ethics Committee.
Collapse
|
|
10 |
56 |
19
|
Marques A, Ollevier F, Verstraete W, Sorgeloos P, Bossier P. Gnotobiotically grown aquatic animals: opportunities to investigate host-microbe interactions. J Appl Microbiol 2006; 100:903-18. [PMID: 16629991 DOI: 10.1111/j.1365-2672.2006.02961.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The culture of aquatic organisms is still hampered by the occurrence of unpredictable diseases in their early life stages, which are responsible for massive mortalities and considerable economic losses. A better understanding of the host-microbe interactions is certainly essential to develop effective solutions of disease control for the aquaculture industry. As demonstrated in terrestrial animals, the use of gnotobiotic systems (animals cultured in axenic conditions or with a known microflora) can be an excellent tool to extent the understanding of the mechanisms involved in host-microbe interactions and to evaluate new treatments of disease control. Several aquatic animals were cultured so far in germ-free conditions, such as fish, molluscs, crustaceans, rotifers, echinoderms, cnidarians, turbellarians, ascidians and echiurans. The aim of the present review is to recapitulate the findings obtained with gnotobiotic aquatic animals over the last decades, with special emphasis to the host-microbe interactions, as well as the perspectives for future research in this field. In addition, the procedures utilized to culture axenic aquatic animals and to verify contaminations are summarized, and the standardization of these procedures is proposed.
Collapse
|
|
19 |
53 |
20
|
Marques A, Lourenço Ó, da Silva JAP. The burden of osteoporotic hip fractures in Portugal: costs, health related quality of life and mortality. Osteoporos Int 2015; 26:2623-30. [PMID: 25986386 DOI: 10.1007/s00198-015-3171-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/07/2015] [Indexed: 02/08/2023]
Abstract
UNLABELLED The study rationale was to provide a detailed overview of the costs, quality of life and mortality of hip fractures in Portugal. Mean individual fracture-related costs were estimated at €13,434 [12,290; 14,576] for the first year and €5985 [4982; 7045] for the second year following the fracture. INTRODUCTION Osteoporotic fractures represent a remarkable burden to health care systems and societies worldwide, which will tend to increase as life expectancy expands and lifestyle changes favour osteoporosis. The cost-effectiveness evaluation of intervention strategies demands accurate data on the epidemiological and economical reality to be addressed. METHODS Information was collected retrospectively on consumption of resources and changes in quality of life attributable to fracture as well as mortality, regarding 186 patients randomly selected to represent the distribution of hip fractures in the Portuguese population, in terms of gender, age and geographical provenience. Data were cross-tabulated with socio-demographic variables and individual resource consumption to estimate the burden of disease. A societal perspective was adopted, including direct and indirect costs. Multivariate analyses were carried out to assess the main determinants of health-related quality of life (HrQoL). RESULTS Mean individual fracture-related costs were estimated at €13,434 [12,290; 14,576] for the first year and €5985 [4982; 7045] for the second year following the fracture. In 2011 the economic burden attributable to osteoporotic hip fractures in Portugal could be estimated at €216 million. Mean reduction in HrQoL 12 months after fracture was estimated at 0.34. Regression analysis showed that age was associated with a higher loss of HrQoL, whereas education had the opposing effect. We observed 12 % excess mortality in the first year after hip fracture, when compared to the gender and age-matched general population. CONCLUSIONS Results of this study indicate that osteoporotic hip fractures are, also in Portugal, despite its low incidence of fractures and cost per event, associated with a high societal burden, in terms of costs, loss in HrQoL and mortality. These data provide valuable input to the design and selection of fracture prevention strategies.
Collapse
|
|
10 |
52 |
21
|
Ramos C, Teixeira B, Batista I, Matos O, Serrano C, Neng NR, Nogueira JMF, Nunes ML, Marques A. Antioxidant and antibacterial activity of essential oil and extracts of bay laurel Laurus nobilis Linnaeus (Lauraceae) from Portugal. Nat Prod Res 2011; 26:518-29. [PMID: 21756182 DOI: 10.1080/14786419.2010.531478] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Laurus nobilis L. is an aromatic plant frequently used as a spice in Mediterranean cookery and as a traditional medicine for the treatment of several infectious diseases. The aim of this study was to characterise the antibacterial and antioxidant activities of bay laurel essential oil (EO), ethanolic extract (EE) and hot/cold aqueous extract (AE). The major components detected in bay laurel EO were eucalyptol (27.2%), α-terpinenyl acetate (10.2%), linalool (8.4%), methyleugenol (5.4%), sabinene (4.0%) and carvacrol (3.2%). The EO exhibited strong antibacterial activity against all tested foodborne spoilage and pathogenic bacteria, whereas this activity was less pronounced or even nonexistent in the EE and AE. In contrast, EO exhibited low antioxidant activity compared to extracts (EX), and among the EX, the hot AE revealed the highest antioxidant ability. The results show that bay laurel EO and its EX have potential as natural alternatives to synthetic food preservatives, in order to enhance food safety and increase food shelf life.
Collapse
|
Research Support, Non-U.S. Gov't |
14 |
50 |
22
|
Lowenfels AB, Maisonneuve P, Grover H, Gerber E, Korsten MA, Antunes MT, Marques A, Pitchumoni CS. Racial factors and the risk of chronic pancreatitis. Am J Gastroenterol 1999; 94:790-4. [PMID: 10086667 DOI: 10.1111/j.1572-0241.1999.00952.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE It is unclear why some alcohol abusers develop alcoholic cirrhosis whereas others contract chronic pancreatitis. The aim of this study was to examine the importance of race as a risk factor for the development of chronic pancreatitis. METHODS We compared the racial status of 1883 patients discharged with a first-listed diagnosis of two diseases strongly related to alcohol abuse: 433 patients with chronic pancreatitis (ICD 5771) and 1450 patients with alcoholic cirrhosis (ICD 5712). Information came from discharge statistics maintained by two acute care hospitals in New York City and one acute care hospital in Lisbon, Portugal. The study period included the years 1989-1996 in the US and 1989-1994 in Portugal. RESULTS A total of 215 (50%) of the 433 chronic pancreatitis patients were black compared with 333 (23%) of the 1450 patients with alcoholic cirrhosis. When adjusted for sex and hospital site, patients with pancreatitis were significantly more likely to be black than patients with cirrhosis (odds ratio 2.5, 95% confidence interval 1.9-3.2, p < 0.001). CONCLUSIONS In comparison with white patients, black patients are two to three times more likely to be hospitalized for chronic pancreatitis than alcoholic cirrhosis. This highly significant (p < 0.001) difference was observed in both men and women: in three different hospitals, and in two different countries. The explanation is unknown, but could be related to racial differences in diet, type or quantity of alcohol consumption, smoking, or ability to detoxify substances harmful to the liver or pancreas.
Collapse
|
Multicenter Study |
26 |
48 |
23
|
Marques A, Minderico C, Martins S, Palmeira A, Ekelund U, Sardinha LB. Cross-sectional and prospective associations between moderate to vigorous physical activity and sedentary time with adiposity in children. Int J Obes (Lond) 2015; 40:28-33. [PMID: 26303349 DOI: 10.1038/ijo.2015.168] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 07/06/2015] [Accepted: 08/13/2015] [Indexed: 11/09/2022]
Abstract
BACKGROUND Physical activity (PA) and sedentary time (SED) have both been suggested as potential risk factors for adiposity in children. However, there is paucity of data examining the temporal associations between these variables. OBJECTIVE This study aimed to analyze the cross-sectional and prospective associations between PA, SED and body composition in children. METHODS A total of 510 children (age at baseline 10.1±0.8, age at follow-up 11.8±0.9) from six Portuguese schools from the Oeiras Municipality participated in this study. PA and SED were measured by accelerometry and trunk fat mass (TFM) and body fat mass (BFM) were measured by dual energy X-ray absorptiometry. Fat mass index (FMI) was calculated as BFM divided by height squared. Several regression models adjusted for age, sex, maturity status, follow-up duration, baseline levels of the outcome variable and SED or moderate to vigorous PA (MVPA) were performed. RESULTS MVPA (min per day) was cross-sectionally inversely associated with adiposity indexes (FMI, TFM and BFM). Adiposity indexes were inversely associated with time in MVPA. In prospective analyses, MVPA was associated with a lower levels of FMI (β=-0.37, 95% confidence interval (CI): -0.49 to -0.26, P<0.001), TFM (β=-0.20, 95% CI: -0.29 to -0.10, P<0.001) and BFM (β=-0.37, 95% CI: -0.49 to -0.26, P<0.001). When the model was adjusted for age, sex, maturity status and for baseline levels of the outcome variables MVPA remained a significant predictor of lower adiposity indexes (FMI: β=-0.09, 95% CI: -0.16 to -0.01, P<0.05; TFM: β=-0.08, 95% CI: -0.15 to -0.01, P<0.05; BFM: β=-0.07, 95% CI: -0.15 to 0.00, P<0.05). Adiposity was not associated with MVPA when modeled as the exposure in prospective analyses. SED was not related with adiposity indexes, except for the relationship with FMI. CONCLUSIONS In cross-sectional and prospective analyses, MVPA is associated with lower adiposity independent of covariates and SED. Results suggest that promoting MVPA is important for preventing gain in adiposity in healthy children.
Collapse
|
Research Support, Non-U.S. Gov't |
10 |
47 |
24
|
Marques A, Marin M, Ruasse MF. Hydrogen peroxide oxidation of mustard-model sulfides catalyzed by iron and manganese tetraarylporphyrines. Oxygen transfer to sulfides versus H(2)O(2) dismutation and catalyst breakdown. J Org Chem 2001; 66:7588-95. [PMID: 11701009 DOI: 10.1021/jo010217r] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fe(III)- and Mn(III)-meso-tetraarylporphyrin catalysis of H(2)O(2) oxidation of dibenzyl and phenyl-2-chloroethyl sulfides, 1, is investigated in ethanol with the aim of designing catalytic systems for mustard decontamination. The sulfide conversion, the sulfoxide and sulfone yields, the oxygen transfer from H(2)O(2) to the sulfide, and the catalyst stability depend markedly on the metal, on the substituents of its ligand, and on the presence or the absence of a cocatalyst, imidazole or ammonium acetate. With Fe, sulfones, the only oxidation products, are readily obtained whatever the ligand (TPP, F(20)TPP, or TDCPP) and the cocatalyst; the oxygen transfer is fairly good, up to 95% when the catalyst concentration is small ([1]/[Cat] = 420); the catalyst breakdown is insignificant only in the absence of any cocatalyst. With Mn, the sulfide conversion is achieved completely when the ligand is TDCPP or TSO(3)PP, but not F(20)TPP or TPP; a mixture of sulfoxide, 2, and sulfone, 3, is always obtained with [2]/[3] = 3.5-0.85 depending on the ligand and the cocatalyst (electron withdrawing substituents favor 3 and NH(4)OAc, 2). The catalyst stability is very good, but the oxygen transfer is poor whatever the ligand and the cocatalyst. These results are discussed in terms of a scheme in which sulfide oxygenation, H(2)O(2) dismutation, and oxidative ligand breaking compete. It is shown that the efficiency of the oxygen transfer is related not only to the rate constant of the dismutation route but also to the concentration of the active metal-oxo intermediate, most likely a perferryl or permanganyl species, i.e., to the rate of its formation.
Collapse
|
|
24 |
46 |
25
|
Martin R, Gran B, Zhao Y, Markovic-Plese S, Bielekova B, Marques A, Sung MH, Hemmer B, Simon R, McFarland HF, Pinilla C. Molecular mimicry and antigen-specific T cell responses in multiple sclerosis and chronic CNS Lyme disease. J Autoimmun 2001; 16:187-92. [PMID: 11334482 DOI: 10.1006/jaut.2000.0501] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The concept of molecular mimicry provides and elegant framework as to how cross-reactivity between antigens from a foreign agent with self proteins may trigger autoimmune diseases. While it was previously thought that sequence and structural homology between foreign and self proteins or the sharing of T cell receptor (TCR) and MHC-binding motifs are required for molecular mimicry to occur, we have shown that even completely unrelated peptide sequences may lead to cross-recognition by T cells. The use of synthetic combinatorial peptide libraries in the positional scanning format (PS-SCL) together with novel biometric prediction approaches has allowed us to describe the recognition profiles of individual autoreactive T cell clones (TCC) with unprecedented accuracy. Through studies of myelin-specific TCC as well as clones from the nervous system of patients suffering from chronic central nervous (CNS) Lyme disease it has become clear that at least some T cells are more degenerate than previously anticipated. These data will not only help us to redefine what constitutes specific T cell recognition, but also allow us to study in more detail the biological role of molecular mimicry. A recent clinical trial with an altered peptide ligand (APL) of one of the candidate myelin basic protein (MBP) epitopes in MS (amino acids 83-99) has shown that such a modified MBP peptide may not only have therapeutic efficacy, but also bears the potential to exacerbate disease. Thus, we provide firm evidence that the basic principles of cross-recognition and their pathogenetic significance are relevant in MS.
Collapse
|
Review |
24 |
45 |