Impact of Poly(L-lactide) versus Poly(L-Lactide-co-Trimethylene Carbonate) on Biological Characteristics of Fibroblasts and Osteoblasts*

Abstract

Bone tissue loss due to injury or disease often requires application ofautologous tissue grafts or artificial biomaterials to fill the fracture. Synthetic biomaterials provide temporary structural support for bone tissue and can be subsequently colonized by host tissue-specific cells. One of the most investigated groups of biomaterials are degradable polymers that naturally decompose in tissues with time. In particular aliphatic polyesters such as polylactides were reported to fulfill biocompatibility requirements as they induce a minor or lack an immune response and integrate with the surrounding tissue. Here we report on the biological effects of two polymers: poly(L-lactide) (PLLA) and a copolymer of L-lactide and trimethylene carbonate (PLTMC) on osteoblasts (MG-63) and fibroblasts (L-929). Osteoblasts are bone forming cells that are in the closest contact with the potential implant while fibroblasts produce the stroma forming the extracellular matrix (ECM) and along with macrophages initiate inflammation. We detected that both types of cells adhered better to PLLA than to PLTMC which might be related to the more rough surface of the former. However, both polymers, but especially PLTMC, increased apoptotic death of both cell types. Moreover, in contrast to PLLA, PLTMC modulated the production of some immune-related mediators by fibroblasts: it increased nitric oxide production and synthesis of numerous pro-inflammatory factors, cytokines (TNF-a and IL-6) activating leukocytes, and ECM-degrading MMP-9 which facilitates leukocyte migration. Thus, overall, our data suggest that PLTMC is less cytocompatible than PLLA.

Metabolomics in Bone Research

“…Furthermore, an increased lactate level followed by polymer breakdown can decrease the amount of intracellular radical oxygen species, reducing the intracellular redox state [ 6 ]. Though biocompatible, with its long degradation period, chronic inflammation is still observed with PLLA with the appearance of pro-inflammation cytokines (IL-1β, TNF and MCP-1) [ 118 , 119 ], even though the metabolism study of this chronic inflammation is still lacking.…”

Poly(L-lactide-co-glycolide) thin films can act as autologous cell carriers for skin tissue engineering

“…However, when compared to TCPS, the proliferation ratio of fibroblasts cultured on these scaffolds was significantly decreased [36]. Studies performed previously by our group showed that PLGA processed into form foils stimulated the typical functions of L929 fibroblasts [26,27,37] and did not induce the release of proinflammatory cytokines from macrophages [29]. Moreover, PLGA foils were found to degrade almost completely after 30 weeks of implantation into rat skeletal muscle [32].…”

“…In previous studies, we performed in vitro and in vivo analyses of several resorbable aliphatic polyesters containing L-lactide, glycolide, ε-caprolactone and trimethylene carbonate with the aim of using them in bone tissue engineering [24][25][26][27]. All of our materials were synthesized with the use of a biocompatible initiator (zirconium (IV) acetylacetonate), in contrast to typically applied tin compounds [28,29].…”