Audrey B. Uknis

Inhibition of plasma kallikrein prevents peptidoglycan-induced arthritis in the Lewis rat.

We investigate whether the previously shown contact system activation plays a pathogenetic role in a rat model of acute inflammation induced by peptidoglycan‐polysaccharide (PG‐APS) using a new specific plasma kallikrein inhibitor, Bz‐Pro‐Phe‐boroArg‐OH (P8720). Group I (control) received neither PG‐APS nor inhibitor. Group II (disease‐treated) received PG‐APS intraperitoneally (IP) and P8720 orally. Group III (disease‐untreated) received PG‐APS IP. Anemia was evident at 49 h in group III but was not present (P < 0.01) in groups I and II. Spleen weight was significantly decreased in group II compared to group III. Acute arthritis progressively developed in group III from 27 to 49 h, but P8720 decreased the joint swelling in group II by 61% (P < 0.0005). We observed a significant fall in prekallikrein and factor XI (P < 0.01) in groups II and III but not in group I. The decrease in the functional levels of high molecular weight kininogen (P < 0.05) observed in group III were prevented by P8720 in group II. The changes in T‐kininogen and α1‐inhibitor 3 acute‐phase proteins were partially prevented by P8720. We conclude that the inflammatory reactions leading to arthritis and anemia, as well as the acute‐phase reaction, are due in part to contact activation, and that specific kallikrein inhibitors may have therapeutic potential.—DeLa Cadena, R. A., Stadnicki, A., Uknis, A. B., Sartor, R. B., Kettner, C. A., Adam, A., Colman, R. W. Inhibition of plasma kallikrein prevents peptidoglycan‐induced arthritis in the Lewis rat. FASEB J. 9, 446–452 (1995)

Bradykinin receptor antagonists type 2 attenuate the inflammatory changes in peptidoglycan-induced acute arthritis in the Lewis rat

Abstract:Objective and Design: We studied the ability of bradykinin (BK) receptor antagonists type 1 and 2 (B1-RA, B2-RA) to prevent acute inflammation.¶Material: A peptidoglycan-polysaccharide (PG-APS)-induced model of arthritis in the Lewis rat was analyzed.¶Treatment: Four groups of animals were studied for 5 days. Treatment was administered subcutaneously (s.c.) 1 mg/kg every 12 h. Group I received PG-APS and was treated with the B2-RA, CP-0597 (DArg-Arg-Pro-Hyp-Gly-Thi-Ser-DTic-NChg-Arg). Group II received PG-APS and was treated with a combined B1 and B2-RA, B9430 (DArg-Arg-Pro-Hyp-Gly-Igl-Ser-DIgl-Oic-Arg). Group III received PG-APS and albumin control. Group IV received albumin control.¶Methods: Joint diameter, liver weight, hematocrit, white blood count and plasma concentrations of prekallikrein, high molecular weight kininogen, HK and IL-1β were measured. Groups were compared by ANOVA.¶Results: Acute arthritis and hepatomegaly were attenuated in the B2-RA-treated animals (p<0.05). Weight loss was more pronounced in the B1/B2-RA-treated animals. Anemia induced by PG-APS was prevented by B2-RA and B1/B2-RA treatment (p<0.001). A marked decrease in plasma HK to 64% of normal was found in the disease-untreated animals, which was completely normalized by B2-RA treatment and partially attenuated by the B1/B2-RA (78%). The decrease in plasma prekallikrein levels was prevented by combined B1/B2-RA treatment (p<0.05). Finally, elevated plasma IL-1β levels were lowered by B1/B2-RA treatment and were below detection limits with the B2-RA treatment.¶Conclusions: These results indicate that the systemic inflammation is due in part to BK generation which can be blocked by B2-RA, while inhibiting the B1 receptor prevents an anti-inflammatory response.¶

Amelioration of inflammation, angiogenesis and CTGF expression in an arthritis model by a TSP1-derived peptide treatment.

Objective: To evaluate the effect of a thrombospondin 1 (TSP1)‐derived peptide on inflammation and angiogenesis in an animal model of erosive arthritis and to assess the relationship between TSP1 and connective tissue growth factor (CTGF) in the pathophysiology of rheumatoid arthritis. Methods: Erosive arthritis in Lewis rats was induced by peptidoglycan‐polysaccharide (PG‐PS). Animals were divided into four groups: (1) negative control and groups receiving, (2) no treatment, (3) treatment with a TSP1‐derived peptide, and (4) treatment with a scrambled peptide. Samples obtained from ankle joint, spleen and liver were studied using histology, histomorphometry, immunohistochemistry and RT‐PCR. Results: Histological data indicated that the TSP1‐derived peptide treatment decreased neovascularization, leukocyte infiltration and thickening of the synovial lining of the joint, and reduced granuloma formation in the spleen and liver when compared to control groups. Higher concentrations of CTGF and TSP1 proteins were observed in the affected areas of animals which did not receive TSP1‐derived peptide treatment. Also, immunofluorescence and RT‐PCR analyses showed an increase in CTGF protein expression and regulation, respectively, in the tissues of untreated animals when compared to the TSP1‐derived peptide treated animals. By immunofluorescence, TSP1 expression was decreased in the TSP1‐derived peptide treated animals. Moreover, macrophage/monocyte‐specific staining revealed a decrease in cell infiltration in the articular tissue of the TSP1‐derived peptide treated animals. Conclusion: Both inflammation and angiogenesis were decreased after TSP1‐derived peptide treatment indicating a potential pathway by which TSP1 interaction with neutrophils induces CTGF in RA affected tissues. J. Cell. Physiol. 211: 504–512, 2007.

Interactions between bradykinin (BK) and cell adhesion molecule (CAM) expression in peptidoglycan-polysaccharide (PG-PS)-induced arthritis.

Bradykinin (BK), a vasoactive, proinflammatory nonapeptide, promotes cell adhesion molecule (CAM) expression, leukocyte sequestration, inter‐endothelial gap formation, and protein extravasation in postcapillary venules. These effects are mediated by bradykinin‐1 (B1R) and‐2 (B2R) receptors. We delineated some of the mechanisms by which BK could influence chronic inflammation by altering CAM expression on leukocytes, endothelium, and synovium in joint sections of peptidoglycan‐polysaccharide‐injected Lewis rats. Blocking B1R results in significantly increased joint inflammation. Immunohistochemistry of the B1R antagonist group revealed increased leukocyte and synovial CD11b and CD54 expression and increased CD11b and CD44 endothelial expression. B2R antagonism decreased leukocyte and synovial CD44 and CD54 and endothelial CD11b expression. Although these findings implicate B2R involvement in the acute phase of inflammation by facilitating leukocyte activation (CD11b), homing (CD44), and transmigration (CD54). Treatment with a B2R antagonist did not affect the disease evolution in this model. In contrast, when both BK receptors are blocked, the aggravation of inflammation by B1R blockade is neutralized and there is no difference from the disease‐untreated model. Our findings suggest that B1R and B2R signaling show physiologic antagonism. B1R signaling suggests involvement in down‐regulation of leukocyte activation, transmigration, and homing. Further studies are needed to evaluate the B1 receptor agonists role in this model.

Thrombospondin-1 and transforming growth factor beta are pro-inflammatory molecules in rheumatoid arthritis

Thrombospondin-1 (TSP1/THBS1) plays a major role in the pathophysiology of rheumatoid arthritis (RA); however, its interface with the cytokine network involved in RA has not been delineated. Correlations were performed between plasma levels of TSP1 and selected cytokines from blood samples collected from 20 patients affected by RA and 13 healthy donors (control). Plasma levels of TSP1 and tissue growth factor beta (TGFbeta) were determined by standard enzyme-linked immunosorbent assay, and cytokines were measured by protein profiling rolling-circle amplification (RCA). TSP1 circulating levels in plasma were found significantly increased in the RA patients when compared with control individuals (P = 0.039). The plasma levels of TGFbeta were also increased in the RA patients, which indicates a statistical trend. Cytokine levels of interleukin (IL)-4, IL-5, IL-12, chemokine CXC 10 (CXCL10/IP10), and chemokine CC 4 (CCL4)/MIP1beta were significantly increased in the RA patients when compared with the control group. In summary, this study demonstrates increased plasma levels of TSP1, which correlated with increased levels of proinflammatory cytokines in plasma of RA patients. More detailed research is required to explore the cytokine imprint yielded by this study and its interface with TSP1 and TGFbeta.

A Monoclonal Antibody to High-Molecular Weight Kininogen Is Therapeutic in a Rodent Model of Reactive Arthritis

We reported that high-molecular weight kininogen is proangiogenic by releasing bradykinin and that a monoclonal antibody to high-molecular weight kininogen, C11C1, blocked its binding to endothelial cells. We now test if this antibody can prevent arthritis and systemic inflammation in a Lewis rat model. We studied 32 animals for 16 days. Group I (negative control) received saline intraperitoneally. Group II (disease-treated) received peptidoglycan-polysaccharide simultaneously with C11C1. Group III (disease-untreated) received peptidoglycan-polysaccharide simultaneously with isotype-matched mouse IgG. Group IV (disease-free-treated) and group V (disease-free isotype-treated) received saline and C11C1 or mouse IgG. Analysis of joint diameter changes showed a decrease in the C11C1 disease-treated group compared to the disease-untreated group. The hind paw inflammatory score showed a decrease in the intensity and extent of inflammation between the disease-untreated and the C11C1 disease-treated group. Prekallikrein, high-molecular weight kininogen, factor XI, and factor XII were decreased in the disease-untreated group compared to the C11C1 disease-treated group. T-kininogen was increased in the disease-untreated group when compared with the C11C1 disease-treated group. Disease-free groups IV and V did not show any sign of inflammation at any time. This study shows that monoclonal antibody C11C1 attenuates plasma kallikrein-kinin system activation, local and systemic inflammation, indicating therapeutic potential in reactive arthritis.

ACR Presidential Address: When You Come to a Fork in the Road, Choose Wisely

As I reflect on my past year, I think about the challenges and opportunities, the external threats—and there have been more than a few this year—and the strength from within that I have had the privilege to experience: core principles, a common vision, strategic thinking, responsible stewardship . . . I am humbled by this experience. I have a deep appreciation for the enormous scope of work that the capable, creative staff and the many hundreds of passionate volunteers are engaged in each year, and that scope continues to grow. We often wonder if the external pressures on the field will overwhelm us, or if our young colleagues will have the passion and commitment to write the next chapter in our profession—to continue to write the history of our great College. The recent past has been dotted with complex issues and uncertain solutions. My thoughts have transitioned in the past several weeks as we have witnessed almost unimaginable insanity, the potential for chaos when order—imperfect though it may be—is clearly within reach. As physicians and community leaders, we have a moral imperative—it is at the core of who we are and what we do. Our external environment is chaotic—an economy in transition, political unrest around the world, poverty ever-present not just in the developing world but right here in our own backyards, barriers to access to health care and education, the cost of health care that threatens our nation’s economic stability. Opinions and belief systems may vary—they should vary—that’s the beauty of our democracy, and it should be an example for all around the world. In our external environment as in our profession, for each of these issues there are many choices to make and there are various roads to follow. We can focus on achieving a commonly agreed-upon goal, and come to collaborative solutions. Idealism is good—it helps us to set our vision and establish a related mission—but realism must rule the day. An inflexible, dogmatic approach, especially when combined with opportunism and self-interest, leads to chaos. . . . everyone loses. The intransigence of our Congress, their prevailing philosophy that a collaborative solution means that we have failed, the lack of a vision for the future that includes supporting success for all, having visual impairment—inability to see the big picture/the collateral moving pieces that lead to instability and failure to achieve the ultimate goal if ignored. . . . all pitfalls to avoid. My message today: When you come to a fork in the road, choose wisely (Figure 1). As FDR so eloquently said, “Democracy cannot succeed unless those who express their choice are prepared to choose wisely. The real safeguard of democracy, therefore, is education.” Two slogans—two campaigns—with which we are familiar. Think about the greater meaning for us today. Each new challenge presents an opportunity to choose wisely. . . . this is our window of opportunity. Excellence in rheumatology education and commitment to lifelong learning, discussion of the most important scientific discoveries in our journals, advocacy for our patients, our members, and our field. . . . this is who we are and what we do. How do we reconcile the reality of limited Presented at the 77th Annual Scientific Meeting of the American College of Rheumatology, October 26, 2013. Audrey B. Uknis, MD: Temple University, Philadelphia, Pennsylvania; President, American College of Rheumatology, 2012– 2013. Address correspondence to Audrey B. Uknis, MD, Temple University School of Medicine, 3401 North Broad Street, Philadelphia, PA 19140. E-mail: auknis@temple.edu. Submitted for publication January 3, 2014; accepted January 3, 2014.