The effect of scaffold degradation rate on three-dimensional cell growth and angiogenesis

Sung, Hsing‐Wen

doi:10.1016/s0142-9612(04)00063-8

Cited by 121 publications

(164 citation statements)

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“…Additionally, slowly degrading polymer microspheres may reduce inflammation. 46 In the present study, inflammatory cell densities were significantly lower in the hybrid tissues formed by PLLA microsphere injection when compared to those formed by PLGA microsphere injection after 6 months.…”

Section: Discussionsupporting

confidence: 39%

“…This acidic environment could negatively affect the viability of cells near the implant and cell migration into the implant in vivo. 46 However, the microsphere surface that would be in contact with host cells after implantation is less acidic than the microsphere core exposed during degradation. 47 The potential problems caused by an acidic microenvironment due to microsphere degradation could be avoided by including a buffering base, such as magnesium hydroxide, in the polymer microspheres.…”

Section: Discussionmentioning

confidence: 99%

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The effect of microsphere degradation rate on the efficacy of polymeric microspheres as bulking agents: An 18‐month follow‐up study

et al. 2006

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The injection of bulking substances has been proposed as a new therapy to treat urinary incontinence and vesicoureteral reflux. Our previous study demonstrated that poly(lacticco-glycolic acid) (PLGA) microspheres have the potential to serve as a bulking agent for urological injection therapies. Hybrid tissues exhibiting a bulking effect were formed in vivo by PLGA microsphere injection, but long-term volume stability was not proven. In this study, we hypothesized that the biodegradation rate of the bulking substance (polymer microspheres) would affect the duration of volume conservation of the induced hybrid tissue. To test this hypothesis, rapidly degrading 75:25 PLGA microspheres and slowly degrading poly(L-lactic acid) (PLLA) microspheres were used as injectable bulking agents for the injection therapy. In vitro degradation tests showed that the mass losses of PLLA and PLGA were 16 and 96% of the initial masses, respectively, at 30 weeks. PLLA and PLGA microspheres were injected into the subcutaneous dorsum of mice. Both types of microspheres were easily injectable through 24-gauge needles. Histological examinations at various time points indicated that host cells from the surrounding tissues migrated to the spaces between both types of injected microspheres and formed new hybrid tissue structures. Lymphocyte migration was noted around the implanted PLGA and PLLA microspheres, but the inflammatory reaction diminished with time. Importantly, the volume of the PLLA hybrid tissues slowly decreased to 52% of the initial volume at 12 months and maintained that volume until 18 months, whereas the volume of the PLGA hybrid tissues rapidly decreased to 22% at 6 months, and the PLGA hybrid tissues disappeared at 11 months. These results show that the biodegradation rate of the bulking substance may be useful for controlling the duration of volume conservation of the induced hybrid tissue.

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Section: Discussionsupporting

confidence: 39%

Section: Discussionmentioning

confidence: 99%

The effect of microsphere degradation rate on the efficacy of polymeric microspheres as bulking agents: An 18‐month follow‐up study

et al. 2006

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“…There was, however, a prominent foreign body giant cell response to the implant, presumably part of the physiological resorption process, 34,45 which was similar in cell-seeded and cell-free constructs. Reaction to foreign material may be nonimmune or elicit an immune response with memory.…”

Section: Discussionmentioning

confidence: 97%

Tissue Engineering for Total Meniscal Substitution: Animal Study in Sheep Model

Kon

Chiari

Marcacci

et al. 2008

Tissue Engineering Part A

113

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Objective: The aim of the study was to investigate the use of a novel hyaluronic acid/polycaprolactone material for meniscal tissue engineering and to evaluate the tissue regeneration after the augmentation of the implant with expanded autologous chondrocytes. Two different surgical implantation techniques in a sheep model were evaluated. Methods: Twenty-four skeletally mature sheep were treated with total medial meniscus replacements, while two meniscectomies served as empty controls. The animals were divided into two groups: cell-free scaffold and scaffold seeded with autologous chondrocytes. Two different surgical techniques were compared: in 12 animals, the implant was sutured to the capsule and to the meniscal ligament; in the other 12 animals, also a transtibial fixation of the horns was used. The animals were euthanized after 4 months. The specimens were assessed by gross inspection and histology.

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“…Com o implante do material sintético o organismo promove uma típica resposta à uma reação inflamatória de corpo estranho. A influência na degradação pela presença de peróxidos, enzimas e células fagocitárias, representa ainda hoje um importante enfoque nas pesquisas dos polímeros bioreabsorvíveis [24,25] .…”

Section: Suportes (Scaffolds) Suportes (Scaffolds) Suportes (Scaffoldunclassified

Polímeros bioreabsorvíveis na engenharia de tecidos

Barbanti

Zavaglia

Duek³

2005

Polímeros

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[3] , sistemas para liberação controlada de drogas [4] , stents [5] e dispositivos ortopédicos [6] . Atualmente fazem parte do cotidiano dos centros cirúrgicos no mundo inteiro.Embora muitos dispositivos protéticos artificiais estejam disponíveis, poucos podem substituir completamente todas as complexas funções biológicas. Em situações clíni-cas mais severas somente o transplante do órgão retoma as atividades orgânicas. Assim, de uma forma idealizada, a melhor alternativa seria obter um novo órgão ou tecido, substituindo aquele que não desempenha normalmente suas funções. Nos dias de hoje, a idéia da reconstrução de órgãos e tecidos criados em laboratório é amplamente difundida e investigada no mundo todo [7,8] . Resumo: A Engenharia de Tecidos consiste em um conjunto de conhecimentos e técnicas para a reconstrução de novos órgãos e tecidos. Baseada em conhecimentos das áreas de ciência e engenharia de materiais, biológica e médica, a técnica envolve a expansão in vitro de células viáveis do paciente doador sobre suportes de polímeros bioreabsorvíveis. O suporte degrada enquanto um novo órgão ou tecido é formado. Os poli(α-hidróxi ácidos) representam a principal classe de polímeros sintéticos bioreabsorvíveis e biodegradáveis utilizados na engenharia de tecidos. No desenvolvimento e na seleção desses materiais, o tempo de degradação é fundamental para o sucesso do implante. Os estudos e os desafios atuais são normalmente direcionados ao entendimento das relações entre composição química, cristalinidade, morfologia do suporte, e o processamento desses materiais. Este artigo faz uma revisão dos trabalhos recentes sobre a utilização dos polímeros sintéticos bioreabsorvíveis como suportes na engenharia de tecidos. Engenharia de tecidos Palavras-chave: Engenharia de tecidos, polímeros bioreabsorvíveis, poli(α-hidróxi ácidos). Bioresorbable Polymers in Tissue EngineeringAbstract: Tissue Engineering is based on a group of techniques for the reconstruction of new organs and tissues. Based on knowledge of materials science and engineering, biology and medicine, the technique involves the in vitro expansion of viable cells obtained from the patient on the polymeric scaffolds. The scaffold degrades while a new organ or tissue is formed. The poly(α-hydroxy acids) are the principal biodegradable and bioresorbable polymers used in tissue engineering. In developing and selecting bioresorbable scaffolds, the degradation time is fundamental for successful biocompatibility and biofuncionality. Hence, degradation studies often address variables such as the chemical composition, crystallinity, morphology of the scaffold and the processing of these materials. This paper reviews recent work in bioresorbable polymers used as scaffolds in the tissue engineering. Keywords: Tissue engineering, bioresorbable polymers, poly(α-hydroxy acids). IntroduçãoQuando a estrutura biológica de um órgão ou tecido não pode ser reparada, a alternativa viável para o restabelecimento das funções normais do paciente é repô-la com um implante feito de um b...

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The effect of scaffold degradation rate on three-dimensional cell growth and angiogenesis

Cited by 121 publications

References 0 publications

The effect of microsphere degradation rate on the efficacy of polymeric microspheres as bulking agents: An 18‐month follow‐up study

The effect of microsphere degradation rate on the efficacy of polymeric microspheres as bulking agents: An 18‐month follow‐up study

Tissue Engineering for Total Meniscal Substitution: Animal Study in Sheep Model

Polímeros bioreabsorvíveis na engenharia de tecidos

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