CURRENT COMMENT Hageman Factor and Acute Gouty Arthritis By R. W. KELLERMEYER I 1900 Freudweiler offered data to support a primary role of urate crystals in the acute inflammatory process of gout as proposed by Garr0d.l At the same time, several prominent investigators supported a theory stating that the deposition of urate crystals at the site of inflammation in gout was secondary to a primary necrotic process.l The primary necrotic process purported to result in tissue breakdown products, which in turn were thought to be responsible for the accumulation of urate crystals, leukocytes, and other components of the exudate. This hypothesis prevailed until the primary role of urate crystals in acute gouty arthritis was firmly established by Seegmiller, Howell, and Malawista? and Faires and McCarty in 1962.3Although this recent work stresses the primary importance of the urate crystals in acute gouty arthritis, it does not define the mechanism which initiates the idammatory process other than to state that the crystals probably serve as an irritant. Inflammation is “a process which begins following a sublethal injury to tissue and ends in complete healing.”* The characteristic changes associated with an acute inflammatory process include pain, swelling, increased warmth, redness and the accumulation of an exudate. These changes are attributed to vasodilation, increased vascular permeability, and the emigration of leukocytes ( polymorphonuclear neutrophils ) to the site of “injury.” The development of N these changes is attributed to pharmacodynamic biochemical agents called inflammatory mediators. The physiologic mechanism for the derivation of these inflammatory mediators is not known. Because the urate crystals associated with acute gouty arthritis are sharp and needlelike, resembling slivers of glass, it is possible that synovial cells are damaged by the sharp urate crystals causing mechanical “sublethal injury to tissue.” Phagocytosis of the urate crystals by synovial cells or tissue macrophages might also injure these cells. This injury could result in the release of intracellular substances, e.g., lysosomal enzymes, into the synovial tissues and synovia1 fluid that would in turn lead to the characteristic findings of inflammation. Although urate crystals might cause the release of inflammatory mediators by damaging the synovial lining cells, it is also possible that urate crystals initiate chemical reactions in the synovial fluid resulting in the development of inflammatory mediators. Since surfaces can cause catalysis, it is possible that the surfaces of the urate crystals induce the development of i d a m matory mediators in the synovial fluid. Proposed Role for Hageman Factor (Factor XZZ) in Acute Gout Hageman factor is an enzymic protein present in plasma in an inactive form. Once activated, Hageman factor can initiate at least two series of chemical reactions in - From the Department of Medicine, Western Reserve University, Cleveland, Ohio 44106. This work was supported b y research grants AM 9560 and AM 07841 from the National Insti452 _ _ _ tutes of Arthritis and Metabolic Diseases. R. W. KELLERMEYER, M.D.: Assistant Professor of Medicine, John G M a y R. Markle Scholar in Academic Medicine. ARTHRITISAND RHEUMATISM, VOL.11, No. 3 (JUNE 1968) ~ 453 HAGEMAN FACTOR AND ACUTE GOUTY ARTHRITIS COMPLEMENT (C'l INFLAMMATORY MEDIATOR PRECURSORS + PLASMINOGEN I FRAGMENT ] PRO-PF KALLIKREINOGEN KININWEN [ N:I ] KALLIKREIN I A F~~~:!~IOASWLAR PLASMIN or C'3 ACTIVATED PERMEABILITY ENHANCING FACTORS CHEMOTACTIC FACTORS C'5.6.7. + [ C'3 \ ALTERATION OF ENOOTl4ELIAL SURFACE PERMEABILITY DIRECTS LEUKOCYTE MIGRATION INTRA-ARTICULAR ENHANCES LEUKOCYTE EMIGRATION PAIN ACCUMULATION GRANULOCYTIC LEUKOCYTES PLASMA P R O T E I N S LACTATE LYSOSOMAL DISRUPTION nYmtoLYTic ENZYMES PROTEOLYTU ENZYMES CATIONIC PROTEIN DECREASED pn ENHANCES CRYSTAL FORMATION TISSUE OlSTRUCTlON 1 ENHANCES IEFLAMMATION PHAGOCYTDSIS OF URATE CRYSTP.LS Fig. 1.-Schematic summary of a proposed inter-relationship of factors that may play a role in the development of the inflammatory process in acute gout. uitro. One reaction results in the activation of the intrinsic clotting system,6 and the other in the formation of factors that induce vasodilation,6 enhance vascular permeability,' stimulate smooth muscle contraction,* and induce pain8 Hageman factor can be activated in uitro by glass, ellagic acid, and numerous forms of particulate material. The comparison of needlelike sodium urate crystals to slivers of glass suggested that Hageman factor might be activated by urate crystal^.^ It was proposed that the activation of Hageman factor in synovial fluid by urate crystals initiates a series of reactions that result in the formation of inflammatory mediators. These mediators then could induce the inflammatory process associated with acute gout. This proposal is supported by the followhg data: ( a ) Hageman factor is activated in vitro by urate crystalsg; ( b ) Hageman factor is present in normal synovial fluidlo; (c) permeability enhancing factors are formed in normal human synovial fluid exposed to urate crystals in uitroll; (d) the permeability enhancing factors are not activated in normal human synovial fluid, if Hageman factor is inactivated by specific antibody1'; and (e) the presence of kinins in synovial fluid exudates from individuals with acute goutf2 The hypothesis that acute gout is initiated by Hageman factor might be applied to other forms of arthritis associated with intra-articular deposition of crystals, e.g., the negatively charged calcium pyrophosphate crystals associated with pseudogout which are known to activate Hageman fac- It is also of interest to note that chickens do not have Hageman factor, nor do they develop an acute inflammatory response following the intra-articular injection of nionosodium urate cry~ta1s.l~ Furthermore, kaolin, a substance that activates Hageman factor and induces a local inflammatory re- 454 R. W. KELLERMEYER man factor does play a role in vivo in the development of an acute inflammatory reaction, i.e., gout, it may not be active in the induction of every inflammatory process. The interrelationship of Hageman factor to several of the inflammatory mediators is Mediators of the Acute Inflammatory summarized in the following paragraphs. Process Bradykinin is a polypeptide composed of A number of factors have been identified nine amino acids and is capable of inand studied in experimental models as pos- creasing capillary permeability, stimulating sible mediators of the acute inflammatory the contraction of smooth muscle, lowering process. Investigators have tried to impli- blood pressure and causing pain, but it does cate one of these factors as the agent re- not induce the accumulation of large numsponsible for all of the changes noted in bers of leukocytes when a “physiologic” acute inflammation, i.e., vasodilation, in- concentration is injected as a single dose creased vascular permeability, pain, and the into skin.lTAlthough not supported by any accumulation of leukocytes. None of the fac- data at present, possibly a slow sustained tors identified thus far appears to be a satis- release of this substance in vivo could lead to significant leukocyte accumulation. factory mediator of all these effects. Several of these mediators, including Bradykinin was initially described by Rocha kinins, PF/dil, and kallikrein, will readily e Silva as a vasodepressor substance reinduce vasodilation, increased vascular per- leased from the pseudo-globulin of blood by meability, and pain, but will not induce the snake venom. There are several activators accumulation of leukocytes unless present of bradykinin, but the only physiologic ones in excessively large amounts. Factors that are granulocytic leukocytes and urate crysinduce the accumulation of leukocytes by t a l ~ . ~ * ~ * “Kallikrein” is a term applied to a group directing the movement of leukocytes through the vascular endothelium to the of vasodepressor substances. Initially this site of injury are called chemotactic agents. activity was described in human urine and ~.~~ an inactive Recently two factors derived from serum p a n c r e a ~ . ~Subsequently, complement components were found to precursor of this substance called kallikrehave chemotactic activity but lack the abil- inogen was identified in blood. Kallikrein ity to induce increased vascular permea- has proteolytic activity that can catalyze bility.14,15Leukocytes accumulating at the the formation of a kinin-like substance in site of injury may release additional inflam- blood called kallidin, a decapeptide with matory mediators in the form of lysosomal the same structure as bradykinin but with hydrolytic enzymes that will enhance the an additional N-terminal lysine. Kallidin may be rapidly converted to bradykinin by inflammatory process.l8 It is likely that the acute inflammatory re- enzymatic cleavage of the N-terminal lysponse is a reflection of the concerted action sine. There are three other identifiable of several mediators, including those that polypeptides with molecular structures and induce vasodilation and increase vascular biologic activities similar to bradykinin, and permeability, those that induce chemotaxis, these are summarily referred to as kinins. and the lysosomal hydrolytic enzymes. It is 21.22 also likely that an acute inflammatory reKinins evolve slowly from plasma kept in sponse can be induced by more than one a glass tube, but they do not evolve when type or group of inflammatory mediators the plasma is prevented from coming in depending on the etiologic agent. If Hage- contact with gla~s.2~ Hageman factor, as sponse when injected intracutaneously in humans, induces less intlammation in an individual with Hageman factor deficiency than in an individual without the deficiency. 455 HAGEMAN FACXOR AND ACUTE GOUTY ARTHRITIS noted above, is also activated by contact Hageman factor + activated Hageman factor with glass surfaces or other similarly negatively charged surfaces. Margolis recog- activated Hageman factor pro-PF + PF nized this and demonstrated that kinins PF kallikreinogen + kallikrein were not generated in plasma from patients kallikrein kininogen + kinin. lacking Hageman factor whether the plasStill other plasma components have been ma was exposed to glass or not. Moreover, linked to the inflammatory process. C'1 esthe addition of purified partially activated terase, the active form of the first compoHageman factor to plasma from a person nent of complement, will cause increased with a congenital deficiency of Hageman vascular permeability when injected intrafactor promoted the formation of kinins8 cutaneously.26 This permeability enhancing PF/ dil (permeability factor/ diluted sebe inhibited by antihistamines, activity can rum) is a factor that develops in guinea suggesting that one of the mediators in this pig or human plasma and induces increased system is histamine. The C'1 esterase-histavascular permeability in the skin of guinea mine system can be activated by antigenpigs following intracutaneous inje~ti0n.l~ antibody complexes, but this does not apSubsequently, it was demonstrated that pear to be dependent on Hageman factor. PF/dil does not develop if the plasma is coltwo additional Histamine and serotonin, lected and prepared in silicone-coated containers. Again the role of glass suggested inflammatory mediators likely to have in that Hageman factor might play a role. This uiuo importance in acute inflammatory role was confirmed by demonstrating that processes, do induce vasodilation and inthe development of PF/dil is dependent on creased vascular permeability, yet neither Hageman factor.24 PF/dil is derived from is a potent chemotactic agent. Further, the an a-globulin precursor in plasma referred release of these substances has no known to as pro-PF. The activated form is not a relationship to Hageman factor. The role of PF/dil, kallikrein, and kinins polypeptide but a larger molecule with properties of a proteolytic enzyme. This in the initiation of an acute inflammatory substance is found in inflammatory em- process was questioned because these subdates, but its role in the acute inflammatory stances were initially reported to produce process is uncertain.l' only short-lived venular damage in the Both PF/dil and kallikrein are proteo- early phases of inflammation, and not to lytic enzymes, both exist as precursor glob- produce the increased capillary permeabilulins in plasma, and both are activated ei- ity that has been proposed to produce the ther directly or indirectly in plasma by major changes in acute inflammatory procHageman factor. Although there was coness. Recently, however, data have been residerable speculation that PF/ dil and kalliported to indicate that the major quantity krein might be identical compounds, Becker of edema in an experimentally induced inand Kagen have separated them by puri6cation pr0cedures.2~PF/ dil and kallikrein flammation is secondary to increased perhave electrophoretic mobilities of beta and meability of the venules, and that leakage gamma globulins and sedimentation values from the capillaries is prominent only in the delayed phase of altered vascular perof 5.7 and 11.3, respectively. meability and probably contributes little to Margolis and others have suggested that the fluid exudate.27 These data offer conHageman factor changes kallikreinogen to siderable support for the possible role of kallikrein directly or through an effect on PF/dil. This proposed interrelationship can permeability factors and kinins in the inflammatory process. be outlined as follow^^^^^^: + + + 456 Role of Inflammatory Mediators in Acute Gouty Arthritis Although it has been demonstrated that urate crystals can induce both a kinin-like activity and permeability enhancing factor with properties similar to PF/dil and kallikrein in normal human synovial fluid,11028 it is unlikely that these agents are responsible for the entire inflammatory process. Injection of bradykinin into a canine joint rapidly induces a transient episode of pain associated with relatively small exudative reaction and accumulation of leukocytes, far less than that associated with the intra-articular injection of urate crystals.29The incomplete and transient nature of this inflammatory response was presented as evidence against the role of kinins in acute gouty arthritis. Yet this response to bradykinin may reflect only one portion of the process leading to acute gout, or it may reflect the rapid destruction of bradykinin, since the half-life in plasma in only a few seconds. Furthermore, Phelps et al. were unable to block the arthritis induced by urate crystals in dogs when carboxypeptidase-B was given intra-arterially or injected into the synovium with the crystals. Carboxypeptidase-B is a potent inhibitor of bradykinin and other kinin polypeptides with C-terminal arginine groups. These authors recognized that it is possible that carboxypeptidase-B does not inhibit the development of arthritis, because the site of kinin release and action is not readily accessible to carboxypeptidase-B. Moreover, it is reasonable to consider that the kinins functioning in acute gouty arthritis are not susceptible to carboxypeptidase-B, since it has been suggested that several plasma kinins exist with different suscepsbilities to enzymatic inactivation.21The experiments by Phelps, Prockop, and McCarty suggest that bradykinin alone does not produce an acute gouty arthritis, yet these studies do not eliminate other kinins as an active component in acute gout. R. W. KELLERMEYER There are no data to support a role for histamine, C’1 esterase, or serotonin in the development of acute gouty arthritis. Role of Leukocytes in Acute Gout The importance of leukocytes to crystalinduced inflammation can be demonstrated experimentally. The acute arthritis induced in dogs by urate crystals does not develop when marked granulocytopenia is induced in the animal by the cytotoxic drug vinblastine (Velbana) .31 There is always the concern that potent cytotoxic agents affect multiple biologic processes of the body and may also interfere with the development of the arthritis by deleting other essential components, yet these data support an essential role of the leukocytes in the development of acute gouty arthritis. Leukocytes accumulating within the synovia can intensify and prolong the intlammatory process ( a ) by releasing proteolytic and hydrolytic enzymes from lysosomes during phagocytosis or cellular disintegration, (b) by decreasing the synovial pH caused by accumulation of lactic acid, and (c) by activating additional kinin. The hydrolytic enzymes released from lysosomes are capable of damaging living cells and will produce an arthritis when injected intra-articularly.l6 Janoff and Zweifach have demonstrated that a cationic protein isolated from the lysosomes of rabbit polymophonuclear leukocytes induces leukocytic emigration from both capillaries and venules and increases vascular permeability.3o This observation suggests that the leukocytes migrating into the joint space early in the inflammatory process could lyse, release cationic protein and enhance the accumulation of additional leukocytes in a cyclic fashion. Leukocytes accumulating at the site of crystal deposition will produce lactic acid as the major end product of their metab.olism, which in turn will bring about a reduction in the pH of the synovial fluid. The maximal pH change is approximately 457 HAGEMAN FACTOR AND ACUTE GOUTY AHTHRITIS 0.5 It is doubtful that t h i s degree of acidity per se will cause tissue destruction, pain, or accentuation of the idammatory process. This change might enhance the effectiveness of enzymatic reactions which promote the infhnmatory process, or it might lead to further crystallization of urate. Leukocytes can induce the activation of kinins in plasma.18 It is, therefore, possible that leukocytes could interact with protein components in synovia or in the plasma exudate to release additional kinins. Chemotactic Factors in Gouty Arthritis As noted previously, none of the kinins or other permeability enhancing factors have been found to be potent chemotactic agents.” Perhaps the kinins act to bring about increased vascular permeability and thereby permit the migration of leukocytes from the vessels into the joint. Leukocytes may be attracted into the joint by still other factors that develop within the synovial fluid and serve as potent chemotactic agents. At the present time, there are no data to support the formation or presence of chemotactic factors in synovial fluid. Ward et al. demonstrated that the formation of either a complex of serum complement components, C’5, 6, and 7,14 or a fragment of C’316 will serve as a potent chemotactic agent. In an in vitro experimental model, bradykinin, kallidin, histamine, serotonin, and cationic protein described by Janoff and Zweifach30 do not possess chemotactic ~r0perties.l~ Complement is present in synovial fluid, but there has been no recognized mechanism for its conversion to a chemotactic agent in acute gout. Recently NafE and Byers have demonstrated that urate crystals will deplete complement in human serum.33If this depletion represents an activation of complement, it is probable that mate crystals could activate chemotactic factor derived from complement similar to those described by Ward. Preliminary evidence suggests that a chemotactic factor does develop in both rabbit and human serum exposed to urate cry~ta1s.a~ Hageman factor may also play a role in chemotaxis. The fragment of C’3 that is reported by Ward to be a chemotactic factor, can be cleaved from C’3 by plasmin.16 There is some evidence to suggest that plasminogen can be converted to ~ ~ con~~~ plasmin by Hageman f a ~ t o rIf. this version of pIasminogen to plasmin is catalyzed by Hageman factor, then it can be proposed that urate crystals might promote the development of a chemotactic factor by activating Hageman factor, which in turn resulted in the formation of plasmin and the C‘3 fragment that is active as a chemotactic agent. In a study done by Graham et al., in the rabbit ear chamber, purged Hageman factor resulted in vasodilation and the accumulation of leukocytes to a greater degree than bradykinin. These data suggest that Hageman factor alone has chemotactic properties, or that it induces the formation of a chemotactic agent.37Whether the reaction is a direct or indirect result of the Hageman factor could not be determined. SUMMARY It is proposed that arthritis induced by intra-articular crystals is initiated by the activation of Hageman factor by the negatively charged crystals (Fig. 1).The activated Hageman factor in turn initiates a series of reactions resulting in the development of permeability enhancing activity, perhaps PF/dil, kallikrein, or kinins. The kallikreins, kinjns, and PF/dil, can initiate the process by inducing vasodilation, increased vascular permeability, and leukocyte emigration though the vessel wall. It is possible that kinins do not direct.the movement of the leukocytes through the tissues to the “site of injury” or the urate crystals and, therefore, fail to large accumulations of leukocytes. The urate crystals may activate still an0KOduce er series of 458 H. W. KELLEXMEYER reactions in the synovi that results in the activation of chemotactic factors from complement components. The chemotactic components could then direct the movement of the leukocytes to the urate crystals resulting in a marked accumulation of leukocytes. The release of lysosomal proteolytic and hydrolytic enzymes from the accumulation of leukocytes may enhance and prolong the inflammatory process. Thus, acute gouty arthritis can be viewed as the end result of several reaction sequences, each responsible for a phase of the inflammatory process. These reactions and others discussed in the body of this report are summarized in Fig. 1. The data supporting the hypothesis implicating Hageman factor in the initiating mechanism of inflammation is discussed. Whether correct or incorrect, the proposal for the initiation of acute gouty arthritis by the activation of Hageman factor-PF-kallikrein-kinin system and possibly chemotactic factors remains attractive and will serve as a working hypothesis to stimulate further experimentation on the mechanism of idammation in gout and other forms of arthritis and to extend our knowledge of the physiologic and pathologic role of biologic inflammatory mediators. Further, the proposal and the experimentation prompted by the proposal encourages a biochemical explanation for the initiation and development of arthritis induced by crystals. SUMMARIO IN INTERLINGUA Es postulate que arthritis inducite per crystallos intra-articular es initiate per le activation de factor de Hageman. Iste activation esserea causate per le negativemente cargate crystallos. Le activate factor de Hageman, de su parte, initiarea un sene de reactiones resultante in le disveloppamento de un activitate que promove le permeabilitate, i.e., possibilemente, PF/dil, kallikreina, o kininas. Le kallikreinas, kininas, e PF/dil pote initiar le processo per inducer vasodilatation, augment0 del permeabilitate vascular, e migration de leucocytos a transverso le pariete vascular. I1 es possibile que kininas non dirige le movimento del leucocytos a transverso le tissu verso le “sit0 del trauma” o le crystallos de urato e assi non produce grande accumulationes de leucocytos. Le crystallos de urato effectua possibilemente le activation de ancora un altere serie de reactiones in le synovio que resulta in le activation de factores chimotactic a b componentes complementari. Postea le componentes chimotactic dirigerea le movimento del leucocytos verso le crystallos de urato con le resultato de un marcate accumulation de leucocytos. Le liberation de lysosomal enzymas proteolytic e hydrolytic ab le accumulation de leucocytos pote promover e prolongar le processo idammatori. Assi acute arthritis guttose pote esser reguardate como le resultato terminal de plure series de reactions, cata-un rsponsabile pro un del phases del processo inflammatori. Le datos que supporta le hypothese de incrimination del factor de Hageman in le initiation del mechanism0 de inflammation es commentate. REFERENCES 1. Freudweiler, M.: Studies on the nature of gouty tophi. Abridged translation with comments by J. M. Brill and D. J. McCarty, Jr. Ann. Intern. Med. 60:486,1964. 2. Seegmiller, J. E., Howell, R. R., and Malawista, S. E.: The inflammatory reaction to sodium urate. Its possible relationship to the genesis of acute gouty arthritis. J.A.M.A. 180: 469,1962. 3. Faires, J. S., and McCarty, D. J., Jr.: Acute arthritis in man and dog after intrasynovial injection of sodium urate crystals. Lancet 2: 682, 1962. 4. Ebert, R. 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