Risk Management in Clinical Trials: Assessment of Current Practices at Portuguese Clinical Trial Sites.

Purpose: Over the last years, in response to the increasing complexity and demand of clinical trials, there has been a growing concern with the application of efficient risk management methodologies. The main objective of this work is to assess the current level of implementation of risk management activities by clinical trials sites' teams and identify points of improvement. Methods: A cross-sectional study was conducted through an original, non-validated questionnaire created to assess the risk management practices at Portuguese clinical trial sites. The web-based survey was sent by e-mail to the clinical trial sites identified, and it was available for one month. Descriptive statistics were used to summarize the findings. Results: In total, 46 clinical trial sites accepted to participate in this study. The surveys' answers showed that although 57.0% of sites reported the use of a systematic risk management tool, only nine sites (19.6%) described a standard tool or document that captured systematically the analysis of risks at the site level. Most of the sites (87.0%) showed willing to use a risk management tool specifically tailored for their operational needs, with the lack of knowledge about risk management being the main reason against its implementation. Conclusion: This work indicates that the surveyed clinical trial sites generally recognize the importance of risk management methodologies as an opportunity to anticipate difficulties in the trial conduct and optimize the use of sites' resources. However, mainly due to lack of experience with risk management methodologies, sites are not currently implementing these strategies in the management of their trial-related operations. The development of a risk management tool for sites can be useful in this context.

Metabolism-Guided Optimization of Tryptophanol-Derived Isoindolinone p53 Activators.

For the first time, the pharmacokinetic (PK) profile of tryptophanol-derived isoindolinones, previously reported as p53 activators, was investigated. From the metabolites' identification, performed by liquid chromatography coupled to high resolution tandem mass spectrometry (LC-HRMS/MS), followed by their preparation and structural elucidation, it was possible to identify that the indole C2 and C3 are the main target of the cytochrome P450 (CYP)-promoted oxidative metabolism in the tryptophanol-derived isoindolinone scaffold. Based on these findings, to search for novel p53 activators a series of 16 enantiopure tryptophanol-derived isoindolinones substituted with a bromine in indole C2 was prepared, in yields of 62-89%, and their antiproliferative activity evaluated in human colon adenocarcinoma HCT116 cell lines with and without p53. Structural optimization led to the identification of two (S)-tryptophanol-derived isoindolinones 3.9-fold and 1.9-fold more active than hit SLMP53-1, respectively. Compounds' metabolic stability evaluation revealed that this substitution led to a metabolic switch, with the impact of Phase I oxidative metabolism being minimized. Through differential scanning fluorimetry (DSF) experiments, the most active compound of the series in cell assays led to an increase in the protein melting temperature (Tm) of 10.39 °C, suggesting an effective binding to wild-type p53 core domain.

Functional and structural impact of 10 ACADM missense mutations on human medium chain acyl-Coa dehydrogenase.

Medium chain acyl-CoA dehydrogenase (MCAD) deficiency (MCADD) is associated with ACADM gene mutations, leading to an impaired function and/or structure of MCAD. Importantly, after import into the mitochondria, MCAD must incorporate a molecule of flavin adenine dinucleotide (FAD) per subunit and assemble into tetramers. However, the effect of MCAD amino acid substitutions on FAD incorporation has not been investigated. Herein, the commonest MCAD variant (p.K304E) and 11 additional rare variants (p.Y48C, p.R55G, p.A88P, p.Y133C, p.A140T, p.D143V, p.G224R, p.L238F, p.V264I, p.Y372N, and p.G377V) were functionally and structurally characterized. Half of the studied variants presented a FAD content <65 % compared to the wild-type. Most of them were recovered as tetramers, except the p.Y372N (mainly as dimers). No correlation was found between the levels of tetramers and FAD content. However, a correlation between FAD content and the cofactor's affinity, proteolytic stability, thermostability, and thermal inactivation was established. We showed that the studied amino acid changes in MCAD may alter the substrate chain-length dependence and the interaction with electron-transferring-flavoprotein (ETF) necessary for a proper functioning electron transfer thus adding additional layers of complexity to the pathological effect of ACADM missense mutations. Although the majority of the variant MCADs presented an impaired capacity to retain FAD during their synthesis, some of them were structurally rescued by cofactor supplementation, suggesting that in the mitochondrial environment the levels and activity of those variants may be dependent of FAD's availability thus contributing for the heterogeneity of the MCADD phenotype found in patients presenting the same genotype.

Desenvolvimento de Competências em Enfermagem Médico-Cirúrgica na Área de Enfermagem à Pessoa em Situação Crítica: Relatório de estágio / Development of Competencies in Medical-Surgical Nursing in the Area of ​​Nursing for the Person in Critical Situation: Internship Report

O presente relatório emerge no âmbito do Curso de Mestrado em Enfermagem à Pessoa em Situação Crítica da Escola Superior de Saúde do Instituto Politécnico de Leiria, cujo objetivo visa a obtenção do grau de Mestre em Enfermagem à Pessoa em Situação Crítica, encontrando-se dividido em 2 partes distintas. A primeira parte evidencia a contextualização dos locais onde decorreram os ensinos clínicos, bem como a reflexão sobre as competências desenvolvidas ao longo dos mesmos, face ao que é emanado pela Ordem dos Enfermeiros como competências comuns do enfermeiro especialista e competências específicas do enfermeiro especialista na área da enfermagem à pessoa em situação crítica. A especialização em enfermagem assume um papel preponderante nos dias de hoje em que, pelos avanços da ciência e da tecnologia, é imprescindível ao profissional de enfermagem uma atualização constante e proativa naquilo que são as melhores intervenções para o doente, resultando de cuidados diferenciados e altamente qualificados. É nessa linha de pensamento que surge a segunda parte deste relatório, uma revisão sistemática da literatura que visa dar resposta à questão de investigação: Qual a eficácia da utilização de solução salina hipertónica em comparação com a utilização de manitol no controlo da pressão intracraniana no doente crítico?

Heterozygous COL4A3/COL4A4 mutations: the hidden part of the iceberg?

BACKGROUND: Single mutations in COL4A3/COL4A4 genes have been described in patients with autosomal dominant Alport syndrome and thin basement membrane nephropathy, without a shared definition of these patients within the medical community. We aimed to better categorize this clinical entity by examining clinical manifestations, family history, pathological features and genetics. METHODS: We retrospectively analyzed patients with causative heterozygous COL4A3/COL4A4 mutations referred to us between 1990 and 2019. Index cases were defined as children who were the first to be diagnosed in their families. RESULTS: The study included 24 index cases and 29 affected relatives, belonging to 25 families with a heterozygous mutation in the COL4A3/COL4A4 genes. During the follow-up, nine patients developed proteinuria [median age 15.7 years (range 5.6-33)], six at clinical diagnosis and four with progression toward chronic kidney disease (CKD) (three required kidney replacement therapy at 25, 45 and 53 years and one had CKD Stage 2 at 46 years). Extrarenal involvement was observed in 24.5% of patients. Hematuria was transmitted in consecutive generations, while CKD was reported in nonconsecutive generations of 11 families [median age 53 years (range 16-80)]. Seventeen patients (32%) underwent kidney biopsy: findings were consistent with Alport syndrome in 12 cases and with thin basement membrane nephropathy in 5 cases. CONCLUSIONS: Despite the benign course for these patients described in the literature, a significant percentage is at risk for disease progression. Consequently, we suggest that the assessment of these patients must take into account family history, genetic analysis and pathologic findings. After comparison with the literature, our data suggest that a different definition for Alport syndrome must be considered.

Portuguese Authorship in Published Clinical Trials: Differences in Industry and Investigator Initiated Trials.

INTRODUCTION: The aim of this study was to investigate the Portuguese authorship in publications resulting from trials initiated by the industry or investigators and run in Portugal. MATERIAL AND METHODS: Clinical trials with Portuguese institutions as sponsor or recruiting centers, and registered in four clinical trial registries, in the last 14 years, were assessed. Publications of completed trials, from both the initiative of the industry and investigatorswere screened and compared. RESULTS: The percentage of published trials initiated by industry and investigators was similar (28.0%). However, the percentage of completed investigator-initiated trials (43.6%) was lower when compared to industry trials (69.7%). There was a higher percentage of Portuguese authorship in published investigator-initiated trials when compared with industry-initiated trials (47.1% vs 8.5%, respectively). Moreover, industry-initiated trials with Portuguese authors were published in journals with lower journal impact factor when compared with those published without authorship of Portuguese investigators. Oncology was the therapeutic area with the highest number of clinical trial registrations and publications. However, in publications with Portuguese authors, industry Initiated trials mainly focused on neurology while investigator-initiated trials had a higher number of papers in the fields of gastroenterology and infection diseases. Published trials with Portuguese authorship, initiated by the industry or investigators, also targeted different populations and had different purposes. In both cases, no significant differences were observed in terms of the journal impact factor or in the alignment of the published randomized trials with the respective reporting guidelines. DISCUSSION: When compared with previous publications, this study showed an increasing trend in the number of clinical trials in Portugal, published within similar timeframes, after trial conclusion. Even though both industry and investigator trials are published within the standards for reporting trials, the low number of Portuguese authorships in industry publications might underline the need for invigorating these independent clinical trials in Portugal by capacitating and empowering national clinical research teams. CONCLUSION: This study confirmed that even though all registered trials had the involvement of Portuguese institutions as a recruiting center, not all the published trials had Portuguese investigators as authors, mainly those initiated by the industry.

Introdução: Este estudo teve por objetivo investigar a autoria Portuguesa em publicações que resultem de ensaios clínicos iniciados pela indústria e por investigadores, que tenham decorrido em Portugal. Material e Métodos: Quatro plataformas de registo de ensaios clínicos foram utilizadas para encontrar ensaios clínicos tendo instituições Portuguesas como promotor ou centro de recrutamento nos últimos 14 anos. Foram analisadas e comparadas as publicações dos estudos completos, da iniciativa da indústria e de investigadores Resultados: A percentagem de ensaios da iniciativa da indústria e de investigadores que são publicados era semelhante (~ 28,0%). Porém, a percentagem de ensaios completos da iniciativa de investigadores era mais baixa (43,6%) quando comparada com os ensaios completos da indústria (69,7%). Existiu uma maior percentagem de autores portugueses em ensaios publicados da iniciativa do investigador quando comparado com os ensaios da iniciativa da indústria (47,1% vs 8,5%). Para além disso, ensaios da iniciativa da indústria com autores portugueses foram publicados em jornais com fatores de impacto inferiores quando comparados com aqueles publicados sem autores portugueses. A oncologia foi a área terapêutica com maior número de ensaios registados e publicados. No entanto, em publicações com autores Portugueses, a indústria focou-se sobretudo na neurologia e os investigadores em gastroenterologia e doenças infeciosas. Ensaios publicados com autores portugueses, iniciados tanto pela indústria como por investigadores, focaram-se em populações diferentes e têm propósitos diferentes. Em ambos os casos, não foram encontradas diferenças estatisticamente significativas no fator de impacto dos jornais, nem no alinhamento dos ensaios aleatorizados publicados com as normas sobre escrita de artigos científicos. Discussão: Quando comparado com publicações anteriores, este estudo mostrou uma tendência de crescimento no número de ensaios clínicos em Portugal, sendo publicados em intervalos de tempo semelhantes após a sua conclusão. Embora os ensaios publicados da iniciativa da indústria e de investigadores estejam alinhados com as normas sobre escrita de artigos científicos, o baixo número de autorias nacionais em publicações de ensaios da indústria, sublinha a necessidade de revigorar os ensaios clínicos da iniciativa de investigadores através da capacitação e emancipação das equipas de investigação nacionais. Conclusão: Apesar de todos os ensaios registados terem o envolvimento de instituições portuguesas como centros de recrutamento, nem todos os ensaios têm autores portugueses nas publicações, principalmente aqueles que são iniciados pela indústria.

Validation of the Portuguese version of Amsterdam Preoperative Anxiety and Information Scale (APAIS).

BACKGROUND: Preoperative anxiety is common among the oncological surgical population. Due to its psychological and physiological detrimental effects, identifying and addressing it is of uttermost importance to improve anesthetic management and patient's outcomes. The aim of this study is to validate the Portuguese version of Amsterdam Preoperative Anxiety and Information Scale (APAIS) in the oncological population. METHODS: Following forward and backward translation of the original APAIS scale, further adaptation was obtained through cognitive interviewing. The resulting instrument was tested on the day before surgery on a sample of adult cancer surgical patients from a Portuguese oncology centre. Psychometric evaluation was derived from inter-item correlation, confirmatory factor analysis, Cronbach's alpha, correlation with comparative scales, receiver operating characteristic curve and Youden index. RESULTS: 109 patients (58 males, 51 females) were included. A three-dimensional model-anxiety about anesthesia, anxiety about surgery and desire for information, showed the best fit to the data. The questionnaire revealed high internal consistency (Cronbach alpha 0.81) and good inter-item correlation. Also, Portuguese APAIS correlated well with the gold standard anxiety scale. Therefore, the psychometric properties of this scale version make it a valid and reliable instrument. The optimal cutoff to maximize both sensitivity and specificity was 12 for the APAIS global anxiety score. CONCLUSIONS: Portuguese APAIS version is an accurate tool to identify preoperative anxiety among cancer patients and might impact its management, from premedication choice to provision of information and reassurance about either anesthesia or surgery.

Magnetic Precipitation: A New Platform for Protein Purification.

One of the trends in downstream processing comprises the use of "anything-but-chromatography" methods to overcome the current downfalls of standard packed-bed chromatography. Precipitation and magnetic separation are two techniques already proven to accomplish protein purification from complex media, yet never used in synergy. With the aim to capture antibodies directly from crude extracts, a new approach combining precipitation and magnetic separation is developed and named as affinity magnetic precipitation. A precipitation screening, based on the Hofmeister series, and a commercial precipitation kit are tested with affinity magnetic particles to assess the best condition for antibody capture from human serum plasma and clarified cell supernatant. The best conditions are obtained when using PEG3350 as precipitant at 4 °C for 1 h, reaching 80% purity and 50% recovery of polyclonal antibodies from plasma, and 99% purity with 97% recovery yield of anti-TNFα mAb from cell supernatants. These results show that the synergetic use of precipitation and magnetic separation can represent an alternative for the efficient capture of antibodies.

Transparency and accuracy in funding investigator-initiated clinical trials: a systematic search in clinical trials databases.

OBJECTIVES: This study aims to identify the sources of funding for investigator-initiated clinical trials (IICTs) in Portugal, and to recommend ways to improve the quality of information collected from clinical trial databases about funding. DESIGN AND METHODS: A systematic search of trial registrations over the last 13 years-using the WHO International Clinical Trials Registry Platform (WHO-ICTRP) and four clinical trials registries (CTRs)-was carried out to identify IICTs in Portugal, used as a case study. Data from the databases were compared with data contained in publications to evaluate the consistency of information on funding sources. The term 'database' is used in this study to refer to both the WHO-ICTRP and the CTRs. When mentioned separately, the WHO-ICTRP is referred to as a 'platform', while the CTRs are referred to as 'registries'. OUTCOME: Suggestions to improve clinical trials databases to clearly identify the funding sources and data ownership in IICTs. RESULTS: Two hundred and eighty-two IICTs were identified in Portugal. Twenty per cent of trials were supported by industry with unclear information on the ownership of the results. Inaccuracy was found in the information about sponsors and funders. The information about funding in all resulting publications (77 out of 133 completed studies) was also inconsistent between databases in 35 out of 77 (45%) of the studies. Notably, 23% of the trials funded by non-profit organisations (n=226) received funds from international and/or national funding agencies. CONCLUSIONS: Identification of IICT funding and ownership of results is unclear in the databases used for this study, which may lead to misunderstandings about the independence of the obtained results. Transparency and accuracy are desirable so that public decision makers and strategic partners can accurately evaluate national performance in this particular type of clinical research.

Successful isolation and ex vivo expansion of human mesenchymal stem/stromal cells obtained from different synovial tissue-derived (biopsy) samples.

Mesenchymal stromal cells (MSC) isolated from synovial tissues constitute a novel source of stem-like cells with promising applications in cartilage regeneration and potentially in other regenerative medicine and tissue-engineering settings. Detailed characterization of these cells is lacking, thus compromising their full potential. Here we present the detailed characterization of the ex vivo expansion of synovium-derived stromal cells collected by three different biopsy methods: synovium-direct biopsy, arthroscopic trocar shaver blade filtrate, and cells isolated from synovial fluid (SF) samples. Isolation success rates were >75% for all sources. MSC obtained from the different samples displayed the characteristic immunophenotype of adult MSC, expressing CD73, CD90, and CD105. Arthroscopic shaver blade-derived cells showed the higher proliferation capacity measured by the fold increase (FI) in total cell number over several passages and considering their cumulative population doublings (CPD; 15 ± 0.85 vs. 13 ± 0.73 for synovium vs. 11 ± 0.97 for SF). Also, these cells were able to sustain an increased proliferation under hypoxic (2% O2 ) conditions (FI 55 ± 4 vs. 37 ± 7) after 17 days in culture. Expanded cells were able to differentiate successfully along the osteogenic, adipogenic, and chondrogenic lineages in vitro. Overall, these results demonstrate that synovial tissues represent a promising source for the isolation of human MSC, while depicting the variability associated to the biopsy method used, which impact cell behavior in vitro.

Study of the removal mechanism of aquatic emergent pollutants by new bio-based chars.

This work is dedicated to study the potential application of char byproducts obtained in the gasification of rice husk (RG char) and rice husk blended with corn cob (RCG char) as removal agents of two emergent aquatic contaminants: tetracycline and caffeine. The chars presented high ash contents (59.5-81.5%), being their mineral content mainly composed of silicon (as silica) and potassium. The samples presented a strong basic character, which was related to its higher mineral oxides content. RCG char presented better textural properties with a higher apparent surface area (144 m2 g-1) and higher micropore content (V micro = 0.05 cm3 g-1). The alkaline character of both chars promoted high ecotoxicity levels on their aqueous eluates; however, the ecotoxic behaviour was eliminated after pH correction. Adsorption experiments showed that RG char presented higher uptake capacity for both tetracycline (12.9 mg g-1) and caffeine (8.0 mg g-1), indicating that textural properties did not play a major role in the adsorption process. For tetracycline, the underlying adsorption mechanism was complexation or ion exchange reactions with the mineral elements of chars. The higher affinity of RG char to caffeine was associated with the higher alkaline character presented by this char.

Leukocytoclastic Vasculitis with Systemic Involvement Associated with Ciprofloxacin Therapy: Case Report and Review of the Literature.

A 71-year-old woman presented with constitutional signs and lower extremity palpable purpura after being prescribed a four-day course of 500 mg of ciprofloxacin two times daily for a gastrointestinal infection. She was admitted for inpatient treatment. During the third hospital day, she presented with an episode of abundant hematemesis while her skin lesions remained unchanged. Upper endoscopy revealed multiple lesions consistent with vasculitis and histological examination of the skin biopsy disclosed a leukocytoclastic vasculitis. The patient was successfully treated with prednisone following ciprofloxacin discontinuation. Complete resolution of the lesions on drug withdrawal strongly suggested drug toxicity, which was further supported by a score of 8 in the Naranjo Adverse Drug Reaction Probability Scale. Awareness that the development of skin and gastrointestinal lesions following administration of ciprofloxacin may be a manifestation of ciprofloxacin-induced vasculitis can help early detection, treatment, and lead to an overall good prognosis.

Advanced cell therapies for articular cartilage regeneration.

Advanced cell-based therapies are promising approaches for stimulating full regeneration of cartilage lesions. In addition to a few commercially available medicinal products, several clinical and preclinical studies are ongoing worldwide. In preclinical settings, high-quality cartilage tissue has been produced using combination strategies involving stem or progenitor cells, biomaterials, and biomolecules to generate a construct for implantation at the lesion site. Cell numbers and mechanical stimulation of the constructs are not commonly considered, but are important parameters to be evaluated in forthcoming clinical studies. We review current clinical and preclinical studies for advanced therapy cartilage regeneration and evaluate the progress of the field.

Evaluation of gene delivery strategies to efficiently overexpress functional HLA-G on human bone marrow stromal cells.

Mesenchymal stromal cells (MSC) constitutively express low levels of human leukocyte antigen-G (HLA-G), which has been shown to contribute to their immunomodulatory and anti-inflammatory properties. Here, we hypothesized that overexpression of HLA-G on bone marrow-derived MSC would improve their immunomodulatory function, thus increasing their therapeutic potential. Therefore, we investigated which gene transfer system is best suited for delivering this molecule while maintaining its immuno-modulatory effects. We performed a side-by-side comparison between three nonviral plasmid-based platforms (pmax-HLA-G1; MC-HLA-G1; pEP-HLA-G1) and a viral system (Lv-HLA-G1) using gene transfer parameters that yielded similar levels of HLA-G1-expressing MSC. Natural killer (NK) cell-mediated lysis assays and T cell proliferation assays showed that MSC modified with the HLA-G1 expressing viral vector had significantly lower susceptibility to NK-lysis and significantly reduced T cell proliferation when compared to nonmodified cells or MSC modified with plasmid. We also show that, in plasmid-modified MSC, an increase in Toll-like receptor (TLR)9 expression is the mechanism responsible for the abrogation of HLA-G1's immunomodulatory effect. Although MSC can be efficiently modified to overexpress HLA-G1 using viral and nonviral strategies, only viral-based delivery of HLA-G1 is suitable for improvement of MSC's immunomodulatory properties.

Isolation and ex vivo expansion of synovial mesenchymal stromal cells for cartilage repair.

BACKGROUND AIMS: Hyaline articular cartilage is a highly specialized tissue that offers a low-friction and wear-resistant interface for weight-bearing surface articulation in diarthrodial joints, but it lacks vascularity. It displays an inherent inability to heal when injured in a skeletally mature individual. Joint-preserving treatment procedures such as mosaicplasty, débridement, perichondrium transplantation and autologous chondrocyte implantation have shown variable results, and the average long-term result is sub-standard. Because of these limitations of the treatment methods and lack of intrinsic repair capacity of mature cartilage tissue, an alternative treatment approach is needed, and synovial mesenchymal stromal cells (SMSCs) represent an attractive therapeutic alternative because of their ex vivo proliferation capacity, multipotency and ability to undergo chondrogenesis. METHODS: SMSCs were isolated from tissues obtained by arthroscopy using two types of biopsies. Ex vivo cell expansion was accomplished under static and dynamic culture followed by characterization of cells according to the International Society for Cellular Therapy guidelines. Kinetic growth models and metabolite analysis were used for understanding the growth profile of these cells. RESULTS: For the first time, SMSCs were expanded in stirred bioreactors and achieved higher cell density in a shorter period of time compared with static culture or with other mesenchymal stromal cell sources. CONCLUSIONS: In this study we were able to achieve (8.8 ± 0.2) × 10(5) cells within <2 weeks in dynamic culture under complete xeno-free conditions. Our results also provided evidence that after dynamic culture these cells had an up-regulation of chondrogenic genes, which can be a potential factor for articular cartilage regeneration in clinical settings.

Nonviral gene delivery to neural stem cells with minicircles by microporation.

The main purpose of this work was to evaluate the transfection of novel DNA vectors, minicircles (mC), on embryonic stem cell-derived neural stem cells (NSC). We demonstrated that by combining microporation with mC, 75% of NSC expressing a transgene is achieved without compromising cell survival, morphology, and differentiation potential. When comparing mC with their plasmid DNA (pDNA) counterparts, both gave rise to similar transfection levels but cells harboring mC showed 10% higher cell viability, maintaining 90% of survival at least for 10 days. Long-term analysis showed that NSC harbor a higher number of mC copies and consequently exhibit higher transgene expression when compared to their pDNA counterpart. Taken together, our results offer the first insights on the use of mC as a novel and safe strategy to genetically engineer NSC envisaging their use as biopharmaceuticals in clinical settings for the treatment of neurodegenerative or neurological diseases.

Direct head-to-head comparison of cationic liposome-mediated gene delivery to mesenchymal stem/stromal cells of different human sources: a comprehensive study.

Nonviral gene delivery to human mesenchymal stem/stromal cells (MSC) can be considered a very promising strategy to improve their intrinsic features, amplifying the therapeutic potential of these cells for clinical applications. In this work, we performed a comprehensive comparison of liposome-mediated gene transfer efficiencies to MSC derived from different human sources-bone marrow (BM MSC), adipose tissue-derived cells (ASC), and umbilical cord matrix (UCM MSC). The results obtained using a green fluorescent protein (GFP)-encoding plasmid indicated that MSC isolated from BM and UCM are more amenable to genetic modification when compared to ASC as they exhibited superior levels of viable, GFP(+) cells 48 hr post-transfection, 58 ± 7.1% and 54 ± 3.8%, respectively, versus 33 ± 4.7%. For all cell sources, high cell recoveries (≈50%) and viabilities (>85%) were achieved, and the transgene expression was maintained for 10 days. Levels of plasmid DNA uptake, as well as kinetics of transgene expression and cellular division, were also determined. Importantly, modified cells were found to retain their characteristic immunophenotypic profile and multilineage differentiation capacity. By using the lipofection protocol optimized herein, we were able to maximize transfection efficiencies to human MSC (maximum of 74% total GFP(+) cells) and show that lipofection is a promising transfection strategy for MSC genetic modification, especially when a transient expression of a therapeutic gene is required. Importantly, we also clearly demonstrated that intrinsic features of MSC from different sources should be taken into consideration when developing and optimizing strategies for MSC engineering with a therapeutic gene.

Plasmid DNA size does affect nonviral gene delivery efficiency in stem cells.

Genetic modification of stem cells, prior to transplantation, can enhance their survival and can improve their function in cell therapy settings. Mesenchymal stem cells (MSC) are considered one of the most promising tools for cell-based gene therapy, due to their multipotency, ease of isolation, as well as their high ex vivo expansion potential. Neural stem cells (NSC) may also present an ideal route for gene therapy and have been considered for use in cell replacement therapies in various neurodegenerative diseases. Gene therapy-based applications require the transfer of genetic material, either by viral or nonviral gene delivery methods, although the latter has been associated with low efficiencies, especially within hard to transfect cells as stem cells. Herein, we present results on the influence of plasmid size in gene delivery to human MSC and mouse NSC. We used minimized plasmids encoding a fluorescent protein but lacking the antibiotic resistance gene. This work shows that (1) for smaller plasmids the intracellular plasmid copy number can be up to 2.6-fold higher, and (2) the number of cells presenting fluorescence can be twice the number obtained for larger plasmids. Furthermore, by using plasmid constructs containing different polyA signals, we also demonstrated that differences between the plasmids depend largely on the transgene mRNA level. Based on our data we demonstrate that plasmid size severely affects the efficiency of nuclear uptake and we propose that it can also affect the rate of heterochromatin associated gene silencing in stem cells.

Genetically engineered stem cell-based strategies for articular cartilage regeneration.

Cartilage is frequently injured, often as a result of inflammatory rheumatic diseases or sports-related trauma. Given its nonvascular nature, articular cartilage has a limited capability for self-repair and currently the few therapeutic options still have uncertain long-term outcomes. Cell-based surgical therapies using autologous chondrocytes to repair cartilage injury have been used in the clinic for over a decade, but this approach has shown mixed results mainly due to the low number of harvested chondrocytes and the loss of cartilage-related phenotype and functionality after several passages of in vitro culture. A wide range of cell sources have been tested to circumvent chondrocyte limitations in cartilage repair, and stem cells have been presented as those that offer the greatest potential for clinical application. This review will focus on recent advances in stem cell-based strategies for articular cartilage repair, specifically focusing on the use of genetically engineered adult stem cells by conventional gene delivery methods and by gene-activated matrices. Perspectives in cartilage engineering are also addressed.