Vera J. Stecher

Alteration of interleukin-1 production and the acute phase response following medication of adjuvant arthritic rats with cyclosporin-A or methotrexate.

The purpose of the paper was to determine whether two clinically active antirheumatic compounds, cyclosporin-A (CS-A) and methotrexate (MTX) were efficacious in the treatment of adjuvant arthritis (AA) in rats, as measured by reduction of paw inflammation, lymphocyte activating factor (LAF) activity and the acute phase response. Parameters of the acute phase response consisted of plasma fibronectin (Fn), C-reactive protein (CRP), albumin and iron. Rats injected with Freunds complete adjuvant on day 1, developed systemic arthritis, which was quantitated by measuring non-injected paw swelling on day 17. When compared to normal animals, AA rats had significantly (P less than or equal to 0.01) increased: (1) splenic LAF activity (100% increase), (2) plasma Fn (58%), and (3) CRP (122%), as well as abnormally reduced levels of: (1) plasma albumin (53% reduction), and (2) iron (54%). Orally dosing AA rats from days 3 to 17 with the immunoregulatory drugs, CS-A (3 and 5 mg/kg) or MTX (0.5 and 1 mg/kg), significantly (P less than or equal to 0.01) reduced paw inflammation (100% reduction), increased final body wt 40-50 g over arthritic controls and decreased LAF activity from splenic leukocytes. The acute phase response, often associated with a high degree of LAF activity, was significantly (P less than or equal to 0.01) decreased by dosing with CS-A (3 and 5 mg/kg) and MTX (0.5 and 1 mg/kg). The inhibition of the acute phase response was measured by reduction of high plasma Fn levels (42-79% decrease) and CRP levels (57-100% decrease) as well as elevation of subnormal levels of plasma albumin (57-101% increase) and iron (40-114% increase). Dosing with the nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin (50 and 100 mg/kg) or phenylbutazone (10 and 30 mg/kg), significantly inhibited paw inflammation (29-85%), but did not decrease the high rate of splenic LAF activity, nor did aspirin (55, 100 and 200 mg/kg) or phenylbutazone (1, 10 and 30 mg/kg) alter the acute phase response in AA rats, as measured by levels of plasma Fn, CRP, albumin and iron. Since CS-A and MTX have been reported to be effective in the treatment of RA, their activity in the LAF, Fn, CRP, albumin and iron assays of the AA rat suggests that these immunological and serological parameters may be useful in identifying potential antirheumatic drugs and distinguishing them from standard NSAIDs.

Modulation of the acute phase response and in vitro measurement of interleukin-1 activity following administration of dexamethasone to adjuvant-arthritic rats

Adjuvant-arthritic (AA) rats were medicated with dexamethasone to determine if this glucocorticoid suppressed the activity of interleukin-1 (IL-1) or the acute phase response. Dexamethasone (0.1 mg/kg, p.o.) administered daily for two weeks to AA rats, significantly (p less than or equal to 0.01) decreased high splenic IL-1 production (60% inhibition). Dexamethasone at a 0.5 mg/kg dose reduced AA rat splenic IL-1 production below normal (100% inhibition). In addition, dexamethasone significantly inhibited the AA rat acute phase response as measured by reduction of plasma C-reactive protein levels and enhancement of plasma albumin and iron levels. Following medication with 0.02, 0.1 or 0.5 mg/kg dexamethasone, high plasma C-reactive protein levels decreased by 33, 77 and 95% respectively, compared to untreated AA controls. Under the same dosing regimen of 0.02, 0.1 or 0.5 mg/kg dexamethasone, plasma albumin levels increased by 44, 128 and 239% respectively, while plasma iron levels rose by 19, 64 and 98% respectively, compared to AA controls. At the 0.02, 0.1 and 0.5 mg/kg doses dexamethasone also significantly reduced injected and noninjected paw swelling in AA rats. In view of the ability of dexamethasone to decrease IL-1 production and the acute phase response often associated with it, it is possible that part of the anti-inflammatory activity of dexamethasone may stem from inhibition of IL-1 formation in vivo.

Single-step purification of rat C-reactive protein and generation of monospecific C-reactive protein antibody.

Although Sepharose-phosphorylcholine affinity chromatography has been used extensively to purify some acute phase proteins, the operation has usually been a laborious multi-step procedure. By modifying previously described multi-step protein purification assays, centigram quantities of pure rat C-reactive protein (CRP) could be obtained in a single chromatographic step using affinity chromatography. Rat serum was passed over a column of p-aminophenylphosphorylcholine and extraneous proteins eluted with Tris-saline-Ca2+ buffer. Similar to other purification procedures, CRP was eluted with phosphorylcholine in a Tris-saline-Ca2+ buffer. The technical detail which distinguished this procedure from others, was the use of a phosphorylcholine gradient shallow enough (0.95 mM-2.5 mM) to resolve the eluent into two peaks; the first peak was composed largely of the contaminant, serum amyloid protein (SAP), and the second was composed of CRP. Although there was some overlap between the first and second peak, pure CRP could be obtained by pooling fractions from the trailing shoulder of the second peak. Using this single step procedure, a greater than 25% yield of SAP-free, purified CRP could be obtained. The purified CRP was free of SAP contamination as measured by sodium dodecyl sulfate gradient polyacrylamide gel electrophoresis. Purified CRP was determined to be free of rat albumin, IgG and the C3 component of complement using immunoelectrophoresis. This one-step affinity column chromatography procedure provides a simple, efficient method for collecting large quantities of rat CRP pure enough to be used to obtain a monospecific goat, anti-rat CRP antibody.

The Effect of Glucocorticoids on Plasma Fibronectin Levels in Normal and Arthritic Rats

In vivo studies with normal and adjuvant-induced arthritic rats were undertaken in order to measure the effects of glucocorticoids on paw inflammation and plasma fibronectin (Fn) levels. Dexamethasone, methylprednisolone, and corticosterone all enhanced plasma Fn levels in normal animals. All drugs also significantly decreased inflammation in arthritic rats as measured by paw swelling. Of the three glucocorticoids, only corticosterone did not significantly enhance Fn levels in arthritic rats, possibly due to its lesser potency and narrow therapeutic window.

Elevation of plasma fibronectin and serum amyloid P in autoimmune NZB, B/W, and MRL/1pr mice.

The acute-phase proteins, fibronectin (Fn) and serum amyloid P (SAP), are opsonins which by virtue of their adhesive properties may be involved in the glomerular nephritis associated with splenic lupus erythematosus (SLE). Because of their possible involvement in the pathophysiology of lupus, plasma Fn and SAP levels from three strains of autoimmune mice were measured over time to determine if Fn and SAP rose as the mice sickened and renal function degenerated. Baseline levels of Fn and SAP were measured when the mice were between 1.5 and 3 months of age. The characteristic rapid onset of autoimmune disease in MRL/1pr mice was accompanied by a two- to threefold increase in plasma Fn and SAP by Day 100. The B/W mice, which develop autoimmune disease more slowly, did not have a significant increase in plasma Fn and SAP until Day 240. The NZB mice, with the most delayed onset of disease, exhibited a modest but significant elevation of plasma Fn and SAP by Day 360. Histologic examination of the kidneys of B/W and NZB mice indicated that pathological abnormality of the glomeruli and tubules coincided with the elevation of plasma Fn and SAP levels. In contrast, blood samples taken over time from normal BALB/c mice did not possess abnormal levels of Fn or SAP. It appears that elevation of plasma Fn and SAP in the MRL/1 pr, B/W, and NZB mice is related to the onset and severity of autoimmune disease and the subsequent loss of renal function.

The Relationship between Plasma Fibronectin Levels and Autoimmune Disease Activity in MRL/I Mice

Abstract Plasma fibronectin levels increased significantly over time in MRL/1 mice with progressive autoimmune disease. At 100 and 120 days of age both male and female MRL/1 mice exhibited significantly higher fibronectin (Fn) levels than the more resistant MRL/n controls. Male mice at early time points had Fn levels no greater than controls due perhaps to the later onset of disease in MRL/1 males. In contrast, female MRL/1 mice, when compared with MRL/n controls, had higher Fn levels from 40 days of age. The proteinuria in these animals was also above MRL/n controls from the first time point taken (Day 40). In a temporal study with female MRL/1 mice, Fn levels peaked at age 120 days and reflected the pattern of the survival curve, indicating that plasma Fn levels have an association with disease activity.

Chapter 18. Disease Modifying Anti-Rheumatic Drugs

Publisher Summary The term disease modifying anti-rheumatic drugs (DMARD) has replaced the term SAARD or slow-acting anti-rheumatic drugs that appeared in the literature for a brief period. This chapter discusses anti-rheumatic drugs defined as those drugs that have shown efficacy as DMRD. To be classified as a DMARD, a drug need not necessarily affect a cure, but rather must retard or stop the underlying progression of the disease. The chapter considers only synthetic compounds and natural products are deliberately excluded. It reviews the possible mechanisms of action of the known DMARDs, their clinical efficacy and side-effects. The severity and extent of side-effects associated with the currently available anti-rheumatic drugs represents the primary reason os their market being limited. The section devoted to new compounds under consideration as DMARDs contains clinical candidates that may represent safer and more efficacious therapy. The DMARD therapeutic category attempts to address the chronic inflammatory response that is of major concern in rheumatology. There are only three classes of synthetic compounds currently marketed in the USA, for which clinical evidence exists for their being classified as DMARDs. These are anti-malarials, gold salts, and d-penicillamine. Therapies with each of these are found to be useful in rheumatology as a consequence of first being used for the treatment of other diseases. Astute clinical observation led to their development as DMARDs. The unknown etiology of the disease combined with the dearth of experimental models that detect DMARDs has made its commercialization formidable.

Lymphocyte activating factor (LAF) and the acute-phase response in adjuvant arthritic rats

The purpose of the study was to determine the temporal relationship between lymphocyte activating factor (LAF) activity and the acute-phase response, as measured by plasma fibronectin (Fn), C-reactive protein (CRP), and albumin levels in adjuvant arthritic rats. LAF activity as measured in the thymocyte costimulator assay, and plasma Fn, CRP, and albumin levels were measured during the acute (Day 3), intermediate (Day 10), and systemic (Day 17) phases of arthritic disease. On Day 3, supernatants from whole spleen cells of adjuvant-injected rats did not exhibit abnormal LAF activity. By Day 10, LAF activity in splenic supernatants from arthritics was significantly (P less than or equal to 0.05) higher than normal, although the increase was no greater than 60%. On Day 17 the LAF activity from arthritic rats had increased an average 300% compared to normals. In contrast to the time course of IL-1 activity, Fn and CRP levels in the arthritic rat were significantly higher than normal at all three time points, although there was a transient fall in Fn and CRP concentrations on Day 10. Plasma albumin levels in arthritic rats were subnormal (P less than or equal to 0.01) on Days 3, 10, and 17, although the concentration of plasma albumin on Day 10 was significantly higher than that measured on Day 3. The acute, intermediate, and systemic phases of adjuvant arthritic paw inflammation paralleled the abnormal profile of Fn, CRP, and albumin concentrations over time. However, LAF activity from arthritic rat spleen cells increased gradually and more closely coincided with the systemic appearance of the disease. Since the appearance of abnormal plasma protein levels in arthritic rats preceded the appearance of increased splenic LAF activity, it appears that there is no causal relationship between enhanced splenic LAF activity and early alteration of plasma Fn, CRP, and albumin levels.