Kinetics of pancreatic tissue proliferation in a polymeric platform in mice

Amitriptyline Downregulates Chronic Inflammatory Response to Biomaterial in Mice

Recent data has signaled that in addition to its therapeutic indications as antidepressant and analgesic, amitriptyline (AM) exerts anti-inflammatory effects in humans and experimental animal models of acute inflammation. We tested the hypothesis that this compound could also modulate the chronic inflammatory process induced by synthetic matrix in mice. Polyether-polyurethane sponge disks were implanted subcutaneously in 9-week-old male C57BL/6 mice. The animals received by oral gavage 5.0 mg/kg of amitriptyline for seven consecutive days in two treatment regimens. In the first series, the treatment was initiated on the day of surgery and the implants removed at day 7 post-implantation. For the assessment of the effect of amitriptyline on chronic inflammation, the treatment was initiated 7 days post-implantation and the sponge discs removed 14 after implantation. The inflammatory markers evaluated, myeloperoxidase - MPO, nitrite content, IL-6, IFN-γ, TNF-α, CXCL1 and CCL2 levels, and NF-κB transcription factor activation were reduced in implants when the treatment began 7 days post-implantation (chronic inflammation). In contrast, only mast cell number, MPO activity and activation of NF-κB pathway decreased when the treatment began soon after implantation (sub-acute inflammation) in 7-day old implants. The anti-inflammatory effects of amitriptyline described here, extend its range of actions as a potential agent able to attenuate long-term inflammatory processes.

Implant-induced inflammatory angiogenesis is up-regulated in obese mice

The damaging effects of obesity extend to multiple pre-existing tissue/organs. However, the influence of this condition on key components (inflammation and angiogenesis) of fibrovascular connective proliferating tissue, essential in repair processes, has been neglected. Our objective in this study was to investigate whether obesity would influence inflammatory-angiogenesis induced by synthetic matrix of polyether-polyurethane implanted subcutaneously in high-fat-fed obese C57/BL6 mice. Fourteen days after implantation, the inflammatory and angiogenic components of the newly formed tissue intra-implant were evaluated. The pro-inflammatory enzyme activities, myeloperoxidase (MPO) and N-acetyl-β-D-glucosaminidase (NAG), the levels of TNF-α, CXCL1/KC and CCL2 and NF-κB transcription factor were examined. Angiogenesis was determined by morphometric analysis of implant blood vessels, intra-implant levels of hemoglobin content, VEGF levels, and western blot for VEGFR2. All inflammatory and angiogenic markers were increased in the implants of obese mice compared with their non-obese counterparts. Similarly, activation of the NF-κB pathway and phosphorylation of VEGFR2 were higher in implants of obese mice (1.60 ± 0.28 Np65/Cp65; 0.96 ± 0.08 p-VEGFR2/VEGFR2-T) compared with implants of non-obese animals (1.40 ± 0.14; 0.49 ± 0.08). These observations suggest that obesity exerts critical role in sponge-induced inflammatory-angiogenesis, possibly by activating fibrovascular components in the inflamed microenvironment. Thus, this pathological condition causes damage not only to pre-existing tissues/organs but also to newly formed proliferating fibrovascular tissue. This is relevant to the development of therapeutic approaches to improve healing processes in patients with obesity.

The emerging field of pancreatic tissue engineering: A systematic review and evidence map of scaffold materials and scaffolding techniques for insulin-secreting cells

A bioartificial endocrine pancreas is proposed as a future alternative to current treatment options. Patients with insulin-secretion deficiency might benefit. This is the first systematic review that provides an overview of scaffold materials and techniques for insulin-secreting cells or cells to be differentiated into insulin-secreting cells. An electronic literature survey was conducted in PubMed/MEDLINE and Web of Science, limited to the past 10 years. A total of 197 articles investigating 60 different materials met the inclusion criteria. The extracted data on materials, cell types, study design, and transplantation sites were plotted into two evidence gap maps. Integral parts of the tissue engineering network such as fabrication technique, extracellular matrix, vascularization, immunoprotection, suitable transplantation sites, and the use of stem cells are highlighted. This systematic review provides an evidence-based structure for future studies. Accumulating evidence shows that scaffold-based tissue engineering can enhance the viability and function or differentiation of insulin-secreting cells both in vitro and in vivo.