Increased expression of Interleukin-13 and connective tissue growth factor, and their potential roles during foreign body encapsulation of subcutaneous implants.
ABSTRACT The purpose of this study was to better understand whether interleukin-13 (IL-13) and connective tissue growth factor (CTGF) are highly expressed during foreign body encapsulation of subcutaneous devices. Mock biosensors were implanted into rats for three lengths of time (7-, 21- and 48-55 days) to address different stages of the foreign body response. Using quantitative real-time PCR and immunofluorescence, the expression of IL13, CTGF, collagen 1, decorin and fibronectin were measured in this tissue. IL-13, a product of Th2 cells, was highly expressed at all time points, with greatest expression at day 21. The IL-13 expression was paralleled by increased presence of T-cells at all time points. CTGF was also found to be more highly expressed in foreign body tissue than in controls. Collagen and decorin were highly expressed at the middle and later stages. Given the increased expression of IL-13 and CTGF in foreign body tissue, and their roles in other fibrotic disorders, these cytokines may well contribute to the formation of the foreign body capsule. Since the peak gene expression of IL-13 occurred later than the previously-reported TGFbeta expression peak, IL-13 is probably not the major stimulus to TGFbeta expression during foreign body encapsulation and may contribute to fibrosis independently.
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ABSTRACT: Catheters are implanted into the peritoneal cavity during the process of peritoneal dialysis. Though these catheters may be effective and beneficial, the impact of catheters on the immune system is poorly understood. Catheters and other devices implanted in the peritoneal cavity elicit a foreign body reaction. However, the immunological consequences of this remain uncharacterized. To model this, catheters were implanted into the peritoneal cavity of healthy mice. Catheter implantation induced rapid cellular changes within the peritoneal cavity. Whereas B-cells and T-cells were reduced, catheter implantation was associated with the rapid expansion of F4/80-low-positive, CD11b-positive macrophages that elaborated IL-10, and suppressed T-cell division and Th1 skewing in co-culture assays. Peritoneal catheter elicited macrophages had increased Jmjd3 but reduced NF-κB activation, and their emergence was MyD88-dependent. Collectively, these studies indicate that foreign body implantation into the peritoneal cavity is associated with the expansion of suppressor macrophages. Whether peritoneal cavity catheter implantation may have systemic immunoregulatory roles remains to be explored.Clinical Immunology 01/2012; 143(1):59-72. · 3.77 Impact Factor
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ABSTRACT: Presently, orthopedic and oral/maxillofacial implants represent a combined $2.8 billion market, a figure expected to experience significant and continued growth. Although traditional permanent implants have been proved clinically efficacious, they are also associated with several drawbacks, including secondary revision and removal surgeries. Non-permanent, biodegradable implants offer a promising alternative for patients, as they provide temporary support and degrade at a rate matching tissue formation, and thus, eliminate the need for secondary surgeries. These implants have been in clinical use for nearly 25 years, competing directly with, or maybe even exceeding, the performance of permanent implants. The initial implantation of biodegradable materials, as with permanent materials, mounts an acute host inflammatory response. Over time, the implant degradation profile and possible degradation product toxicity mediate long-term biodegradable implant-induced inflammation. However, unlike permanent implants, this inflammation is likely to cease once the material disappears. Implant-mediated inflammation is a critical determinant for implant success. Thus, for the development of a proactive biodegradable implant that has the ability to promote optimal bone regeneration and minimal detrimental inflammation, a thorough understanding of short- and long-term inflammatory events is required. Here, we discuss an array of biodegradable orthopedic implants, their associated short- and long- term inflammatory effects, and methods to mediate these inflammatory events.Journal of Long-Term Effects of Medical Implants 01/2011; 21(2):93-122.
- Regenerative Medicine and Tissue Engineering - Cells and Biomaterials, 08/2011; , ISBN: 978-953-307-663-8