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Despite the advances in the treatment of rheumatoid arthritis (RA) achieved in the last few years, several patients are diagnosed late, do not respond to or have to stop therapy because of inefficacy and/or toxicity, leaving still a huge unmet need. Tissue-specific strategies have the potential to address some of these issues. The aim of the study is the development of a safe nanotechnology approach for tissue-specific delivery of drugs and diagnostic probes. CD34 + endothelial precursors were addressed in inflamed synovium using targeted biodegradable nanoparticles (tBNPs). These nanostructures were made of poly-lactic acid, poly-caprolactone, and PEG and then coated with a synovial homing peptide. Immunofluorescence analysis clearly demonstrated their capacity to selectively address CD34 + endothelial cells in synovial tissue obtained from human, mouse, and rat. Biodistribution studies in two different animal models of rheumatoid arthritis (antigen-induced arthritis/AIA and collagen-induced arthritis/CIA) confirmed the selective accumulation in inflamed joints but also evidenced the capacity of tBNP to detect early phases of the disease and the preferential liver elimination. The therapeutic effect of methotrexate (MTX)-loaded tBNPs were studied in comparison with conventional MTX doses. MTX-loaded tBNPs prevented and treated CIA and AIA at a lower dose and reduced administration frequency than MTX. Moreover, MTX-loaded tBNP showed a novel mechanism of action, in which the particles target and kill CD34 + endothelial progenitors, preventing neo-angiogenesis and, consequently, synovial inflammation. tBNPs represent a stable and safe platform to develop highly-sensitive imaging and therapeutic approaches in RA targeting specifically synovial neo-angiogenesis to reduce local inflammation.

Complement C1q is the activator of the classical pathway. However, it is now recognized that C1q can exert functions unrelated to complement activation. Here we show that C1q, but not C4, is expressed in the stroma and vascular endothelium of several human malignant tumours. Compared with wild-type (WT) or C3- or C5-deficient mice, C1q-deficient (C1qa−/−) mice bearing a syngeneic B16 melanoma exhibit a slower tumour growth and prolonged survival. This effect is not attributable to differences in the tumour-infiltrating immune cells. Tumours developing in WT mice display early deposition of C1q, higher vascular density and an increase in the number of lung metastases compared with C1qa−/− mice. Bone marrow (BM) chimeras between C1qa−/− and WT mice identify non-BM-derived cells as the main local source of C1q that can promote cancer cell adhesion, migration and proliferation. Together these findings support a role for locally synthesized C1q in promoting tumour growth., C1q is known to initiate the activation of the complement classical pathway. Here, the authors show the C1q is expressed in the tumour microenvironment and can promote cancer cell migration and adhesion in a complement activation-independent manner.

Objective To show that a new recombinant protein (MT07) obtained by fusing a synovial-homing peptide to a neutralizing antibody to C5 can be selectively delivered to inflamed synovium and can effectively control joint inflammation in experimental models of arthritis. Methods Binding of MT07 to human, rat, and mouse synovial tissue was evaluated in vitro by immunofluorescence, and selective localization in the inflamed joints of rats was documented in vivo using time-domain optical imaging. The antiinflammatory effect of MT07 was tested in a rat model of antigen-induced arthritis (AIA) and in a mouse model of collagen antibody–induced arthritis (CAIA). Results MT07 was able to bind to samples of inflamed synovium from humans, mice, and rats while failing to recognize uninflamed synovium as well as inflamed mouse lung or rat kidney. In vivo analysis of the biodistribution of MT07 confirmed its preferential homing to inflamed joints, with negligible inhibition of circulating C5 levels. MT07 prevented and resolved established inflammation in a rat model of AIA, as demonstrated by changes in joint swelling, polymorphonuclear cell counts in synovial washes, release of interleukin-6 and tumor necrosis factor α, and tissue damage. A similar therapeutic effect was obtained testing MT07 in a CAIA model. Conclusion Our findings show that the novel recombinant molecule MT07 has the unique ability to selectively target inflamed joints and to exert local control of the inflammatory process by neutralizing the complement system without interfering with circulating C5 levels. We believe that this approach can be extended to other antiinflammatory drugs currently used to treat patients with rheumatoid arthritis.

SUMMARYComplement activation plays a relevant role in the development of tissue damage under inflammatory conditions, and clinical and experimental observations emphasize its contribution to inflammatory vasculitides. Statins have recently been shown to reduce cardiovascular morbidity independently of plasma cholesterol lowering and in vitro studies support a direct anti-inflammatory action of these drugs. The aim of this study was to verify the in vivo effect of fluvastatin on complement-mediated acute peritoneal inflammation. The effect of oral treatment with fluvastatin was investigated in normo-cholesterolaemic rats that received intraperitoneal injection of either yeast-activated rat serum (Y-act RS) or lipopolysaccharide to induce peritoneal inflammation monitored by the number of PMN recruited in peritoneal fluid washes. In addition, vascular adherence and extravasation of leucocytes were evaluated by direct videomicroscopy examination on mesentery postcapillary venules topically exposed to Y-act RS. The number of PMN in the peritoneal washes of rats treated with fluvastatin was 38% lower than that of untreated animals (P

Objective To verify if innate immunity, and namely the assembly of terminal complement complex (TCC) could be involved in the development of early diabetic vascular damage. Methods and results At first in 2 groups of diabetic or non-diabetic Wistar rats the occurrence of basal or stimulated stable adherence to the endothelial layer and extravasation of circulating fluorescently-labelled leukocytes was assessed by using an in vivo videomicroscopy technique. In a second part of the study, the development of vascular damage in short term diabetes was studied in the genetically C6 deficient rats of the PVG strain, and compared with those observed in the wild-type C6 sufficient animals. Here, the analysis of mesentery vascular expression of mRNA for vascular cell adhesion molecule (VCAM)-1, transforming growth factor-β (TGF-β), connective tissue growth factor (CTGF), and platelet-derived growth factor (PDGF), the evaluation of intravascular protein levels of VCAM-1, TGF-β, CTGF, proliferative cell nuclear antigen (PCNA), as well as the assessment of structural changes and Complement components deposition at the mesentery arterial vascular wall were also performed. Conclusions Leukocyte trafficking, mesentery arteries hypertrophy, extracellular matrix deposition, local vascular gene and protein expression of VCAM-1, TGF-β, CTGF and PCNA, as well as PGDF gene expression were all increased by short term diabetes, but all significantly reduced in the C6 deficient diabetic animals, thus suggesting an active role for TCC in the development of vascular inflammation in the early phases of experimental diabetes.