Efetividade das coberturas e agentes tópicos de matriz no tratamento de úlceras de perna: revisão sistemática e metanálise / Effectiveness of coverings and topical matrix agents in the treatment of leg ulcers: systematic review and meta-analysis

Resumo: As úlceras vasculogênicas (venosas, arteriais e mistas) são um tipo de ferida crônica, apresentam altos índices de prevalência e incidência mundial, são recorrentes, alteram a qualidade de vida, são susceptíveis a complicações, como a infecção, e geram altos custos para os prestadores de serviço. Em feridas crônicas os altos níveis de metaloproteinases, na fase inflamatória, destroem as proteínas essenciais para a formação da matriz extracelular (MEC), impedem a aderência das células, a angiogênese, a MEC degrada-se e retarda a cicatrização. As tecnologias de matriz estimulam os componentes ou substituem a matriz extracelular danificada, para otimizar a cicatrização. Esta revisão sistemática (RS) objetivou sintetizar as evidências da diversidade das tecnologias de matriz (origem, fonte e composição), aplicadas como coberturas e agentes tópicos, no tratamento de úlceras vasculogênicas, em adultos, a partir dos 18 anos, em qualquer ambiente de cuidado. Os desfechos foram: cicatrização, tempo para completar a cicatrização, infecção, redução da área, dor e qualidade de vida. Foram seguidas as recomendações do Instituto Joanna Briggs, o protocolo foi publicado (JBISRIR-2017-003400R1) e registrado no PROSPERO (CRD42018100125). Incluíram-se ensaios clínicos randomizados (ECR), publicados em inglês, português e espanhol, a partir de 1960. Os estudos foram identificados por meio da busca nas bases de dados MEDLINE/PUBMED, EMBASE, CINAHL, LILACS, WEB OF SCIENCE; banco de teses e dissertações e plataformas de registros de ECR. A qualidade da evidência foi classificada com base no sistema GRADE. Identificaram-se 992 estudos, após a aplicação dos critérios de elegibilidade por dois revisores independentes; 41 estudos foram incluídos, desses 7 inclusos à metanálise. Os produtos de matriz foram organizados em três categorias (Colágeno, Biocelulose e Outras matrizes) e dez subcategorias. No desfecho cicatrização, comparado à cobertura não-aderente, na subcategoria colágeno humano, a metanálise favoreceu o grupo colágeno humano de camada dérmica, porém, sem significância estatística (RR=1,21; IC95%:0,91-1,60; p=0,20), heterogeneidade baixa (I2= 28%). Na subcategoria colágeno suíno, o percentual de cicatrização foi, significativamente, maior para o grupo colágeno suíno (RR=1,57; IC95%:1,18-2,09; p=0,002), heterogeneidade baixa (I2=0%). Na subcategoria biocelulose bacteriana, houve diferença significativa no percentual de cicatrização entre os grupos, porém, sem significância estatística (RR=0,74; IC:95%:0,37-1,48; p=0,39), heterogeneidade baixa (I2=0%). No desfecho infecção, na subcategoria colágeno humano, o resultado da metanálise favoreceu o colágeno humano, porém, sem significância estatística (RR=0,92; IC 95%:0,64-1,31; p=0,64), heterogeneidade baixa (I2=0%). Embora as matrizes tenham demonstrado superioridade, em alguns dos demais desfechos, como: tempo para completar a cicatrização, redução da área, dor e qualidade de vida, as evidências ainda são limitadas ou muito limitadas, em decorrência de viés metodológico e imprecisão, levando à certeza baixa ou muito baixa, atribuídas aos estudos, conforme julgamento por meio do GRADE. Entretanto, não houve evidências que refutassem a aplicação dessas tecnologias de matriz nas úlceras vasculogênicas. Recomenda-se, dessa forma, a realização de novos estudos que poderão alterar a confiança na estimativa de efeito e, portanto, o grau de certeza destes achados.

Abstract: Vasculogenic ulcers (venous, arterial and mixed) are a type of chronic wound, presenting high prevalence rates and global incidence, they are recurrent, alter the quality of life, susceptible to complications, such as infection, and generate high costs for the service providers. In chronic wounds, high levels of metalloproteinases, in the inflammatory phase, destroy essential extracellular matrix (ECM) proteins, impede cell adhesion, angiogenesis, ECM degrades and delays healing. Matrix technologies stimulate the components or replace the damaged extracellular matrix to optimize healing. This systematic review aimed to synthesize evidence of the diversity of matrix technologies (origin, source and composition), applied as topical coverages and agents in the treatment of vasculogenic ulcers in adults, from 18 years of age, in any care environment. The outcomes were: healing, time to complete healing, infection, reduction of area, pain and quality of life. The recommendations of the Joanna Briggs Institute were followed, the protocol was published (JBISRIR-2017- 003400R1) and registered in PROSPERO (CRD42018100125). It were included Randomized Controlled Trials (RCTs), published in English, Portuguese and Spanish, published from 1960. The studies were identified through the search in the databases MEDLINE/PUBMED, EMBASE, CINAHL, LILACS, WEB OF SCIENCE; bank of theses, dissertations, and platforms of records of RTCs. The quality of the evidence was classified based on the GRADE system. Two independent reviewers identified 992 studies following the eligibility criteria; 41 studies were included, of these 7 included in the metaanalysis. The matrix products were organized into three categories (Collagen, Biocellulose and Other Matrices) and ten subcategories. In the outcome "healing", compared to the non-adherent coverages, in the subcategory human collagen, the meta- analysis favored the human collagen group of the dermal layer, but without statistical significance (RR = 1.21, 95% CI: 0.91-1.60; p = 0.20), low heterogeneity (I 2 = 28%). In the subcategory pig collagen, the percentage of healing was significantly higher for the pig collagen group (RR = 1.57, 95% CI: 1.18-2.09, p = 0.002), low heterogeneity (I 2 = 0%). In the subcategory bacterial biocellulose, there was a significant difference in the percentage of healing between the groups, however, without statistical significance (RR = 0.74, CI: 95%: 0.37-1.48, p = 0.39), low heterogeneity (I 2 = 0%). In the outcome "infection", in the subcategory of human collagen, the results of the meta- analysis favored human collagen, but, without statistical significance (RR = 0.92, 95% CI: 0.64-1.31, p = 0.64), heterogeneity low (I 2 = 0%). Although the matrices have shown superiority, in some of the other outcomes, such as: time to complete healing, reduction of area, pain and quality of life, the evidence is still limited or very limited, due to methodological bias and imprecision, leading to low or very low confidence, attributed to the studies, according to GRADE judgment. However, there was no evidence to refute the application of these matrix technologies in vasculogenic ulcers. Therefore, it is recommended to carry out new studies that may after the confidence in the effect estimate and, therefore, the degree of certainty of these findings.

Maintenance of hPSCs under Xeno-Free and Chemically Defined Culture Conditions

Previously, the majority of human embryonic stem cells and human induced pluripotent stem cells have been derived on feeder layers and chemically undefined medium. Those media components related to feeder cells, or animal products, often greatly affect the consistency of the cell culture. There are clear advantages of a defined, xeno-free, and feeder-free culture system for human pluripotent stem cells (hPSCs) cultures, since consistency in the formulations prevents lot-to-lot variability. Eliminating all non-human components reduces health risks for downstream applications, and those environments reduce potential immunological reactions from stem cells. Therefore, development of feeder-free hPSCs culture systems has been an important focus of hPSCs research. Recently, researchers have established a variety of culture systems in a defined combination, xeno-free matrix and medium that supports the growth and differentiation of hPSCs. Here we described detailed hPSCs culture methods under feeder-free and chemically defined conditions using vitronetin and TeSR-E8 medium including supplement bioactive lysophospholipid for promoting hPSCs proliferation and maintaining stemness.

The effect of mechanical stretching stress on the proliferation, apoptosis of degenerative disc nucleus pulposus cells and expression of extracellular matrix / 中华物理医学与康复杂志

Objective To observe in vitro the effect of mechanical stress at different intensities on the pro-liferation, apoptosis and extracellular matrix of degenerative human nucleus pulposus cells. Methods The cells were isolated and cultured in vitro, and divided into a control group, a low-intensity group, a medium-intensity group and a high-intensity group. The low-, medium- and high-intensity groups were stretched mechanically by 1000 μ, 2000μor 4000μrespectively for 6 hours using a four-point bending system, while the control group was not stressed. Flow cytometry was used to explore any changes in the cell cycle and the proliferation index ( PI) . The expression of proliferating cell nuclear antigen ( PCNA) , B-cell lymphoma-2 ( BCL-2)/Bax, collagen II and aggrecan were meas-ured using real-time quantitative polymerase chain reactions. Results The mechanical stretching significantly influ-enced proliferation, apoptosis and the extracellular matrices compared with the control group. The PI and PCNA ex-pression increased at first and then decreased gradually with the exercise intensity. Compared with the control group, the mRNA expression level of Bcl-2/Bax increased significantly to 1.53 times that of the control group after 1000 μstretching, but to only 0.71 times that of the control group at 2000μand 0.43 times at 4000μ. The gene expression of collagen II increased significantly by 1. 1 times and that of aggrecan by 1. 3 times after 1000 μ stress stimulation compared with the control group ( P≤0.05) . However, the expression of collagen II and aggrecan was inhibited sig-nificantly at 2000 and 4000 μ , with the lowest levels at 4000 μ (P≤0.05). Conclusion Stretching at different intensities has different effects on the proliferation, apoptosis and extracellular matrix of human pulposus cells with degenerate nuclei.

Transplantation of stem cell-preseeded dentin slices incorporated with periodontal ligament cell sheets from beagle dog into nude mice / 实用口腔医学杂志

Objective:To observe the effects of dentin proseeded with BMSCs or PDLCs incorporated with PDLCs sheets and calci-nated ceramic bovine bone(CBB)in the reconstruction of periodontal tissue.Methods:Root dentin slices were prepared and pre-seeded with BMSCs or PDLCs from beagle dog.After cultivated in osteoinduction medium(OST groups)orα-modified eagle's medi-um(MEM groups)for 3 weeks,the dentin slices observed by scanning electron microscope (SEM).Then the slices were wrapped successively with PDLCs sheets and CBB as new constructs(BMSCs or PDLCs/dentin/PDLCs sheets/CBB).The new constructs were transplanted into nude mice subcutaneously,8 week after transplantation,samples were havested and examined by HE staining.Re-sults:Enough cells and extracellular matrices were detected on the dentin slices by SEM in vitro.A little new immature cementum-like tissue without periodontal-like tissue on the surface of the new construcs was observed in OST groups.By contrast,in MEM groups,periodontal-like without immature cementum-like tissue formation was observed.Conclusion:Dentin proseeded with BMSCs or PDLCs incorporated with PDLCs sheets and CBB cultured by MEM can promote periodontal-like tissue regeneration.Cultured with osteooinduction medium can promote cementum-like tissue regeneration.