Fibrinogen γ' promotes host survival during Staphylococcus aureus septicemia in mice

BACKGROUND

Staphylococcus aureus is a common gram-positive bacterium that is the causative agent for several human diseases, including sepsis. A key virulence mechanism is pathogen binding to host fibrinogen through the C-terminal region of the γ-chain. Previous work demonstrated that FggΔ5 mice expressing mutant fibrinogen γΔ5 lacking a S. aureus binding motif had significantly improved survival following S. aureus septicemia. Fibrinogen γ' is a human splice variant that represents about 10% to 15% of the total fibrinogen in plasma and circulates as a fibrinogen γ'-γ heterodimer (phFibγ'-γ). The fibrinogen γ'-chain is also expected to lack S. aureus binding function.

OBJECTIVE

Determine if human fibrinogen γ'-γ confers host protection during S. aureus septicemia.

METHODS

Analyses of survival and the host response following S. aureus septicemia challenge in FggΔ5 mice and mice reconstituted with purified phFibγ'-γ or phFibγ-γ.

RESULTS

Reconstitution of fibrinogen-deficient or wildtype mice with purified phFibγ'-γ prior to infection provided a significant prolongation in host survival relative to mice reconstituted with purified phFibγ-γ, which was superior to that observed with heterozygous FggΔ5 mice. Improved survival could not be accounted for by quantitative differences in fibrinogen-dependent adhesion or clumping, but phFibγ'-γ-containing mixtures generated notably smaller bacterial aggregates. Importantly, administration of phFibγ'-γ after infection also provided a therapeutic benefit by prolonging host survival relative to administration of phFibγ-γ.

CONCLUSION

These findings provide the proof-of-concept that changing the ratio of naturally occurring fibrinogen variants in blood could offer significant therapeutic potential against bacterial infection and potentially other diseases.

[Pathogenesis study of inherited dysfibrinogenemia]

OBJECTIVE

To explore the pathogenesis of a family with inherited dysfibrinogenemia.

METHODS

Coagulation parameters of peripheral venous blood of a family with inherited dysfibrinogenemia from November 2012 were measured. And platelet and fibrinogen functions were examined by thromboelastogram. The antigen concentration of fibrinogen was detected by immune nephelometry. All exons and exon-intron boundaries of FGA, FGB and FGG were amplified and subjected to mutation screening by direct/reverse sequencing. And the influences of mutant fibrinogen structure and function were analyzed and predicated by a molecular structure model.

RESULTS

The values of activated partial thromboplastin time (APTT), D-dimer and fibrinogen antigen of the propositus and his mother (I-2), younger brother (II-3), younger sister (II-2) and daughter (III-1) were all in normal reference value ranges.However thrombin time (TT) was significantly prolonged and the activity of fibrinogen was much lower compared to its antigenicity. Thromboelastogram indicated normal function of platelet and impaired function of fibrinogen of I-2, II-2 and III-1.However the fibrinogen functions of proband and II-3 became much more impaired. Mutation screening demonstrated the homozygous mutation of proband and II-3 while I-2, II-2 and III-1 showed heterozygous mutation of FGG c.1001 A>C (p. Asn308Thr). No mutation was detected among other family members and reducing SDS-PAGE immunoblot showed no variants. Asn308, located at the interface of fibrinogen dimmer, participated in the fibrous structure assembling from the structure model. And mutation at this position will affect the stability of fiber structure.

CONCLUSION

FGG c.1001 A>C mutation may account for dominant genetic dysfibrinogenemia in these family members.

Acquired dysfibrinogenemia in atherosclerotic vascular disease

Acquired qualitative abnormalities of fibrinogen molecules, termed acquired dysfibrinogenemia, have been demonstrated in several disease states mostly related to prothrombotic tendency, including multiple myeloma and liver disease. Fibrin is abundant in atherosclerotic plaques. Altered plasma fibrin properties, reflected usually by reduced clot permeability and impaired fibrinolysis, have been reported in patients with acute or prior myocardial infarction, ischemic stroke, and peripheral artery disease. Moreover, prothrombotic clot phenotype has been observed in patients with previous no-reflow phenomenon and stent thrombosis. Growing evidence indicates that acquired dysfibrinogenemia contributes to the progression of atherosclerotic vascular disease and the occurrence of its thrombotic manifestations. The review summarizes current knowledge on the links between fibrin clot phenotype and atherosclerotic vascular disease and describes a wide spectrum of cardiovascular risk factors as modifiers of fibrin network characteristics.

Healing of ulcers due to cryofibrinogenemia with colchicine and high-dose pentoxifylline

Cryofibrinogenemia is due to the presence of reversibly cold-precipitating plasma proteins and material, consisting mostly of fibrinogen, fibronectin, and fibrin. This condition can be idiopathic or secondary to infection, thromboembolic states, neoplasm, or connective tissue disease. The characteristic lesions of cryofibrinogenemia include purpura and ulcerations. Histologically, the lesions of cryofibrinogenemia demonstrate fibrin thrombi within vessels, with no evidence of vasculitis. Treatment of cryofibrinogenemia should be directed at the underlying disease process, if one can be found. Other treatments have included the anabolic steroid stanozolol, which is presently unavailable, anticoagulants, immunosuppressive agents, plasmapheresis, and the combination of streptokinase and streptodornase. We report a case of a 61-year-old male smoker with a 10-year history of intermittent ulcerations of both legs and feet. Two separate biopsies showed epidermal ulceration and thrombi within superficial dermal vessels without evidence of vasculitis. These findings, together with the presence of elevated plasma cryofibrinogen, led to the diagnosis of cryofibrinogenemia. The patient continued to have ulcerations despite efforts to control his high blood pressure, cold avoidance, local wound care, and treatment with pentoxifylline 800 mg three times daily. However, when colchicine 0.6 mg twice daily was added to the patient's care, this led to rapid healing of his ulcerations. He has remained ulcer free for 2 years taking the combination of colchicine and high-dose pentoxifylline. Efforts to reduce the dose of these agents have repeatedly led to recurrences, and remission has promptly followed re-establishment of the combination. To our knowledge, this is the first report documenting use of the combination of colchicine and high-dose pentoxifylline to successfully treat ulcers due to cryofibrinogenemia.

Update on antithrombin I (fibrin)

Antithrombin I (fibrin) is an important inhibitor of thrombin generation that functions by sequestering thrombin in the forming fibrin clot, and also by reducing the catalytic activity of fibrinbound thrombin. Thrombin binding to fibrin takes place at two classes of non-substrate sites: 1) in the fibrin E domain (two per molecule) through interaction with thrombin exosite 1; 2) at a single site on each gamma' chain through interaction with thrombin exosite 2. The latter reaction results in allosteric changes that down-regulate thrombin catalytic activity. Antithrombin I deficiency (afibrinogenemia), defective thrombin binding to fibrin (antithrombin I defect) found in certain dysfibrinogenemias (e.g. fibrinogen Naples 1), or a reduced plasma gamma' chain content (reduced antithrombin I activity), predispose to intravascular thrombosis.

Rare Bleeding Disorder Registry: deficiencies of factors II, V, VII, X, XIII, fibrinogen and dysfibrinogenemias

A North American registry for rare bleeding disorders [factor (F)II, factor (F)VII, factor (F)X, factor (F)V, factor (F)XIII, fibrinogen deficiencies and dysfibrinogenemias] was established to gather information about disease prevalence, genotyping frequency, diagnostic events, clinical manifestations, treatment and prophylaxis strategies, as well as disease- and treatment-related complications. Questionnaires were sent to 225 hemophilia treatment centers in the USA and Canada. Among 26% of responding centers, 294 individuals [4.4% of the registered children (200/4583) and 2.4% of adults (94/3809)] were diagnosed with one or more of the rare bleeding disorders (RBDs) included in this survey. The ethnic distribution for each disorder paralleled that of the general US population with the exception of the disproportionately large number of Latinos with FII deficiency. Only 5.4% of affected individuals were genotyped. An abnormal preoperative bleeding screen most often led to diagnosis. The most common coagulopathy was FVII deficiency; however, 40% of homozygous patients were asymptomatic. FX and FXIII deficiencies caused the most severe bleeding manifestations. Among all RBDs, the most common sites of bleeding were skin and mucus membranes. Multiple products were used to treat hemorrhage; however, half of the bleeding episodes required no therapy. The majority of patients suffered no long-term complications from hemorrhage. Treatment-related complications included viral seroconversion, anemia, allergic reactions and venous access device-related events. This registry provides the most comprehensive information to date about North American individuals with RBDs and could serve as an important resource for both basic scientist and clinician.

Axillary vein thrombosis and congenital dysfibrinogenemia in a commercial pilot: a case report

A 34-yr-old male commercial pilot developed a painful swollen right upper arm following an episode of trauma. Venography confirmed the clinical diagnosis of a right axillary deep venous thrombosis. Magnetic resonance imaging suggested the presence of a fibrous tissue band overlying the junction of the right subclavian and innominate veins, potentially creating a thoracic outlet syndrome. A thrombophilia screen revealed an abnormal fibrinogen variant consistent with a diagnosis of congenital dysfibrinogenemia. The pilot was treated with anticoagulant therapy for 4 mo. There were diagnostic difficulties in determining the definitive etiology of the axillary vein thrombosis. Congenital dysfibrinogenemia is a rare condition, which is asymptomatic in the majority, but may manifest with hemorrhage or thrombosis in up to 45% of cases. The clinical management of the pilot and the aeromedical implications of the diagnosis are discussed.

Familial hypofibrinogenaemia associated with heterozygous substitution of a conserved arginine residue; Bbeta255 Arg-->His (Fibrinogen Merivale)

Sequencing of all three fibrinogen genes from an individual with hypofibrinogenaemia led to the identification of two new point mutations in the Bbeta gene. Family studies showed the mutations Bbeta255 Arg-->His (Fibrinogen Merivale) and Bbeta148 Lys-->Asn (Fibrinogen Merivale II) were on different alleles and that only the Bbeta255 Arg-->His mutation segregated with hypofibrinogenaemia. Three simple heterozygotes for this mutation had mean fibrinogen concentrations of 1.4 mg/ml, while heterozygotes for the Bbeta148 Lys-->Asn mutation had normal fibrinogen concentrations. ESI MS analysis of endoproteinase Asp-N digests of Bbeta chains showed that the Bbeta255 Arg-->His substitution was not expressed in plasma, confirming it as the cause of the hypofibrinogenaemia. The Bbeta148 Lys-->Asn chains, on the other hand, were equally expressed with wild-type Bbeta chains in simple heterozygotes. Genotype analysis failed to detect either substitution in 182 healthy controls. Arg(255) is located in the first strand of the five-stranded sheet that forms the main feature of the betaD domain and appears to form an essential H bond with Gly(414). Both the Arg and Gly are absolutely conserved, not only in all known Bbeta chains, but also in all homologous alphaE and gamma chains and in all fibrinogen-related proteins. Protein instability from loss of this contact could easily explain the association of this mutation with hypofibrinogenaemia.

Cryofibrinogen: formation and inhibition in heparinized plasma

Cold precipitable proteins (cryoglobulins, cryofibrinogen, and heparin-precipitable fractions) have presented a considerable problem to the clinician in treatment of patients who are discovered to have such fractions and to the cardiac surgeon who is confronted with clogged filters in heart surgery with hypothermia. When heparin, 0.04 mg/ml blood, is added as an anticoagulant, fibrin threads or clots may be observed in the red cell mass. The plasma of such blood, when exposed to temperatures of 5 C for 16 hr will show two precipitable fractions, one of which is soluble at 37 C whereas the other is not. As the heparin concentration is increased, there is a serial disappearance of each fraction. The heat-soluble fraction is the last to disappear, and this occurs when the heparin concentration reaches 3.0 mg/ml blood. Normal blood similarly treated with sodium oxalate or sodium citrate shows no cold precipitation. Normal plasma, after addition of thrombin, shows both cold-precipitable fractions. Twelve patients who had varying amounts of cryofibrinogen were studied by employing a modification of the thromboplastin generation test. Eight of the twelve patients showed a hypercoagulable state.

Erythrocyte hyperaggregation and thrombogenic dysfibrinogenemia

Erythrocyte aggregation was measured in 12 patients with congenital dysfibrinogenemia. The results showed hyperaggregation in four patients who had presented a thrombotic disorder, while aggregation was entirely normal in patients with asymptomatic dysfibrinogenemia. None of the four symptomatic patients had any other anomaly of hemostasis, in particular no coagulation inhibitor deficit or anti-phospholipid antibodies. The possible involvement of erythrocyte hyperaggregation in the thrombotic process is discussed.

Spontaneous necrosis of the skin associated with cryofibrinogenemia, cryoglobulinemia, and homocystinuria

Cryofibrinogenemia has been associated with a variety of skin manifestations including purpura, livedo reticularis, and ulceration. Our patient, who had undergone axillobifemoral bypass 5 years previously, presented following the spontaneous development of a necrotic wound involving the left groin scar. The location of the wound suggested the possibility of underlying graft infection, but indium-111 white blood cell scan and MRI failed to show any evidence of infection. The patient was initially treated with oral antibiotics and outpatient debridement with no improvement. A more aggressive approach with inpatient operative debridement and intravenous antibiotics produced moderate improvement. Three months later, the patient developed an identical necrotic wound in the right groin and subsequently a third lesion involving a scar distant from any of the patient's grafts. No evidence of active vasculitis was seen on microscopic examination of the excised tissues. Cryoglobulin and cryofibrinogen assays were positive, and urinary and plasma homocysteine levels were elevated. The patient was subsequently treated with stanozolol, a low-methionine diet, and outpatient intravenous antibiotics with rapid improvement of her wounds. In patients with spontaneous ulceration of the extremities, particularly when they do not respond appropriately to standard therapy, the possibility of cryoglobulinemia or cryofibrinogenemia should be considered.

Monoclonal cryo-antifibrinogenemia

We report on a 54-year-old female patient with arthritis and a severe cold-induced leukocytoclastic vasculitis of the skin caused by a rare form of cryofibrinogenemia ("type II" cryofibrinogen). Affinity chromatography of cryoprecipitates from the patient's plasma revealed reversible cryoprecipitability of complexes composed of fibrinogen and a monoclonal antifibrinogen antibody (IgG3 kappa). Conventional serum and plasma electrophoresis did not detect the paraprotein. Control of symptoms was achieved by long-term plasmapheresis.

A case of cryofibrinogenaemia responsive to stanozolol

Cryofibrinogen is a plasma protein complex whose presence in the peripheral blood is generally asymptomatic, but may sometimes cause multiple thromboembolism in the skin, lung and myocardium. The pathological manifestations associated with cryofibrinogenaemia have been treated with plasmapheresis and fibrinolytic drugs such as streptokinase, streptodornase and/or urokinase. Good results have recently been reported with stanozolol. This prompted us to treat a patient suffering from cryofibrinogenaemia with this androgenic hormone. The patient was a 66-year-old woman with rapidly evolving leg ulcers. Stanozolol was orally administered at 4 mg b.i.d. for 5 months and then gradually reduced. Plasma cryofibrinogen disappeared after 45 d from the start of therapy and cutaneous ulcers healed in 5 months.

The ultrastructure of fibrinogen Caracas II molecules, fibers, and clots

Fibrinogen Caracas II is an abnormal fibrinogen involving the mutation of A alpha serine 434 to N-glycosylated asparagine. Some effects of this mutation on the ultrastructure of fibrinogen Caracas II molecules, fibers, and clots were investigated by electron microscopy. Electron microscopy of rotary shadowed individual molecules indicated that most of the alphaC domains of fibrinogen Caracas II do not interact with each other or with the central domain, in contrast to control fibrinogen. Negatively contrasted Caracas II fibers were thinner and less ordered than control fibers, and many free fiber ends were observed. Scanning electron microscopy of whole clots revealed the presence of large pores bounded by local fiber networks made up of thin fibers. Permeation experiments also indicated that the average pore diameter was larger than that of control clots. The viscoelastic properties of the Caracas II clot, as measured by a torsion pendulum, were similar to those of control clots. Both the normal stiffness and increased permeability of the Caracas II clots are consistent with the observation that subjects with this dysfibrinogenemia are asymptomatic.

Stanozolol as a novel therapeutic agent in dermatology

Anabolic steroids are synthetic derivatives of testosterone that were developed in the 1950s in an attempt to dissociate the anabolic and androgenic effects of testosterone. The anabolic steroid stanozolol has been particularly helpful because it has one of the largest anabolic/androgenic ratios. In addition, stanozolol has substantial fibrinolytic properties. We discuss the safety profile and the use of stanozolol for a variety of clinical applications. Stanozolol is approved for use in the treatment of hereditary angioedema, but numerous reports have detailed the effectiveness of this agent in the treatment of urticaria, Raynaud's phenomenon, and, more recently, cryofibrinogenemia and lipodermatosclerosis. Side effects are mostly dose related and are preventable with appropriate follow-up.

[Cold labile serum and plasma proteins: clinical and diagnostic significance of cryoglobulins, cryofibrinogen and cold agglutinins]

Cold labile serum and plasma proteins can cause a variety of clinicopathological symptoms. Due to altered physicochemical properties, cryoglobulins and cryofibrinogens may cause increased serum viscosity, cold dependent protein precipitation or, in rare cases, serum gelification. Cold agglutinins, on the other hand, cause temperature dependent agglutination of erythrocytes and eventually hemolysis. All pathological cold dependent serum and plasma phenomena are associated with either neoplasma, autoimmune disorders, various infections or are considered as "essential". While the diagnosis of these conditions remained largely unchanged during the last 10 years, new aspects regarding etiology, pathogenesis, and therapy have arisen.

[Cryofibrinogenemia: apropos of a case]

We describe the case of a 70-years-old woman with ischemic-hemorrhagic lesions in the cutaneous surface of both feet and analytical data of disseminated intravascular coagulation, in which the studies conducted were negative except for the presence of cryofibrinogen in plasma. We also review the clinical manifestations and the diseases associated to cryofibrinogenemia previously described in the literature.

[Essential cryofibrinogenemia with generalized livedo racemosa]

A 45-year-old male patient presented with cold-induced generalized livedo reticularis, repeated acral ulcerations and purpura, Raynaud's phenomenon, and peripheral polyneuropathy. The patient also experienced malaise, vertigo, and transient amaurosis whenever he was exposed to low temperatures. Skin biopsies of the livedo reticularis revealed marked dilatation of the small dermal blood vessels and circumscribed leukocytoclastic vasculitis. Essential cryofibrinogenaemia was diagnosed on the basis of detection of this cryoprotein in the chilled blood plasma with increased viscosity. Pulsed therapy with dexamethasone and cyclophosphamide resulted in marked relief of the symptoms, and cryofibrinogen was no longer detectable in the patient's plasma.

Essential cryofibrinogenaemia, leukocytoclastic vasculitis and chronic purpura

Cryofibrinogenaemia refers to the presence of cold-precipitable proteins in plasma but not in serum. It is usually associated with malignancy, thromboembolic diseases or various inflammatory processes; rarely it may be essential. The most common clinical presentations of cryofibrinogenaemia are cold-intolerance, purpura, skin necrosis and ulcers. We describe a middle-aged woman with essential cryofibrinogenaemia, leukocytoclastic vasculitis, and chronic purpura for over 25 years with several exacerbations. In patients with otherwise unexplained purpura or skin necrosis, determination of plasma cryofibrinogen should be considered.

Stanozolol causes rapid pain relief and healing of cutaneous ulcers caused by cryofibrinogenemia

BACKGROUND

Cutaneous manifestations of cryofibrinogenemia include purpura, ecchymosis, and ulcerations. The histology of these lesions is characterized by intravascular thrombi.

OBJECTIVE

Our purpose was to test the efficacy of stanozolol, a drug capable of fibrinolytic enhancement, in treating cutaneous ulcers caused by cryofibrinogenemia.

METHODS

Eight patients with cutaneous ulcerations from cryofibrinogenemia were treated with stanozolol. Plasma cryofibrinogen was measured before and during treatment with stanozolol. Histologic evaluation was also performed before treatment and in selected patients during treatment.

RESULTS

After treatment, seven of the eight patients had healing of their ulcers, prompt reduction in their pain, and improvement in livedo reticularis and purpura. Four of the eight patients had no detectable plasma cryofibrinogen after treatment. In addition, dermal intravascular thrombi resolved. Stanozolol was well tolerated and had minimal side effects.

CONCLUSION

We conclude that stanozolol is a safe and effective treatment of the cutaneous manifestations of cryofibrinogenemia.

A case of neutrophilic dermatosis (ND) complicated by cryofibrinogenemia (CFGN) and myelodysplastic syndrome (MDS)

A case of neutrophilic dermatosis (ND) complicated by cryofibrinogenemia (CFGN) and myelodysplastic syndrome (MDS) is reported. Although the patient presented pancytopenia, the skin lesions were compatible with those of ND from the clinical and histopathological findings. Further, immunofluorescence technique revealed cryofibrinogen (CFG) deposits on the walls of the blood vessels in the skin lesion, and a high titer of CFG components was disclosed in the patient's peripheral blood. In this case, CFGN may have been associated with MDS; hence CFG deposits probably played a role, at least in part, in the skin lesion formation. This is probably the first case of ND complicated by CFGN. And careful examination of an underlying disease is recommended in association with ND and/or CFGN.

Intravascular coagulation necrosis of the skin associated with cryofibrinogenemia, diabetes mellitus, and cardiolipin autoantibodies

Intravascular coagulation necrosis of the skin is rare and appears as hemorrhagic infiltrates that may develop ulcerating necrosis, mainly on the acral areas. The face, arms, and legs were severely involved in our patient. In this patient intravascular coagulation necrosis was associated with cryofibrinogenemia, diabetes mellitus, and IgM cardiolipin autoantibodies. In addition, rheumatoid factor, elevated polyclonal IgA, and haptoglobin were present as risk factors for the vasculopathy. Skin biopsy specimens showed plugging of dermal venules by thrombi formed of fibrin and erythrocytes. Immunohistologic staining revealed a strong positive reaction for fibrinogen, with some positivity for C3, C4, IgG, IgA, and IgM. Erythrocyte extravasation occurred in late lesions without being accompanied by perivascular leukocytic infiltrates. Detailed clinical examination failed to identify an underlying malignancy. Treatment with heparin and prednisolone produced only a brief remission. However, the combination of chlorambucil (7 mg/day orally) with low-dose oral prednisolone (10 mg/day) for several weeks controlled the disease and greatly reduced the cryofibrinogen. No relapse occurred after discontinuation of treatment.

Stanozolol in treatment of leg ulcers due to cryofibrinogenaemia

Five consecutive patients with cryofibrinogenaemia in association with painful leg ulcers and intravascular dermal thrombi were treated with stanozolol, an androgenic steroid with fibrinolytic properties. In all patients treatment was followed by rapid and striking pain relief and healing of the ulcers. Cryofibrinogenaemia was not detected on subsequent laboratory evaluation, and dermal intravascular thrombi had resolved on repeat histological examination.

Cryofibrinogenaemia: a case report

A case of chronic acral ulceration is described in a 54-year-old man with cryofibrinogenaemia. Initial management with prednisolone and azathioprine was unsuccessful in controlling the disease. Introduction of a programme of plasmapheresis in addition to treatment with cyclophosphamide and prednisolone has brought about marked improvement.

An A alpha Ser-434 to N-glycosylated Asn substitution in a dysfibrinogen, fibrinogen Caracas II, characterized by impaired fibrin gel formation

We have identified a unique N-glycosylated Asn substitution for a Ser at position 434 of the A alpha chain of an abnormal fibrinogen designated fibrinogen Caracas II. This dysfibrinogen was characterized by impaired fibrin monomer aggregation. Since there were 4 Thr residues immediately following the mutation, a new Asn-X-Thr/Ser-type consensus sequence, Asn-Thr-Thr arose for N-glycosylation of the Asn. The extra oligosaccharide was found to consist mainly of a disialylated biantennary structure comprising 81.9%, while a neutral and a monosialylated biantennary oligosaccharide represented only 3.6% and 14.5%, respectively. The mutation resides in the carboxyl-terminal region of the A alpha chain, which could fold back to form an extra small globular region located near the central region of the molecule (Erickson, H.P., and Fowler, W.E. (1983) Ann. N. Y. Acad. Sci. 408, 146-163; Weisel, H.P., Stauffacher, C.V., Bullitt, E., and Cohen, C. (1985) Science 230, 3124-3133). Therefore, the participation of this region, referred to as an additional central domain or an alpha domain, in fibrin gel formation is strongly implicated.

[Cryofibrinogenemia--successful therapy by decreasing fibrinogen]

Six patients suffering from solitary cryofibrinogenaemia are described. In one patient idiopathic cryofibrinogenaemia was present, while the others showed secondary cryofibrinogenaemia associated with borrelia infection, chronic venous insufficiency with pulmonary embolism, primary biliary cirrhosis, diabetes mellitus or von-Willebrand syndrome. Subcutaneous injections of the thrombin-like snake poison batroxobin/ancrod were administered over a period of several weeks. Five patients experienced almost complete remission of their symptoms, especially of pain following cold exposure. In one patient partial relief was achieved. Overall we found a 75% reduction of symptoms. When blood fibrinogen levels are carefully monitored this therapy is an efficient and safe form of treatment for cryofibrinogenaemia.

Cryofibrinogenemia: report of a case

Cryofibrinogenemia, a rare disease, is diagnosed by the presence of reversible cryoprecipitate in plasma, which may cause various clinical manifestations of thromboembolic or hemorrhagic disorders. A 66-year-old female patient suffered from recurrent reticulate erythema, purpura and gangrene on the distal portion of the extremities and face during the winter for 5 years. Cryofibrinogenemia was proven with the following evidences: (1) Histopathologic findings revealed many eosinophilic cylinders, about 6-9 microns in diameter, deposited within the lumen of the blood vessels in the dermis and subcutaneous tissue. There was no evidence of vasculitis. These cylinders were fibrinogen in nature, as proven by direct immunofluorescence. (2) Cryofibrinogen was detected in the citrated plasma, which was confirmed by double immunodiffusion, the presence of an IgG-kappa M protein was also revealed by immunofixation. Debridement and skin grafts were performed, and prednisolone combined with cyclophosphamide were given. Skin lesions improved without recurrence, and the "cryocrit" decreased from 13.6% to less than 2% during the follow up. We conclude that if there is any case with the similar cutaneous manifestations, cryofibrinogenemia should be considered.

Superficial migratory thrombophlebitis and factor XII deficiency

A patient with painful migratory erythematous nodules for 7 years is presented. The nodules, which were localized on the lower and upper extremities, progressed to palpable cords. Multiple venograms showed no evidence of deep vein thrombosis. Skin biopsy specimens were diagnostic of superficial thrombophlebitis. There was no evidence of internal malignancy. Extensive evaluation for an underlying hypercoagulable state was remarkable for a factor XII level 17% of normal. The patient was unresponsive to a wide range of treatments. The recalcitrant nature of his disease and lack of deep venous involvement are unique. An underlying hypercoagulable state should be considered when the diagnosis of superficial migratory thrombophlebitis is considered.

Transient nephrotic syndrome after anaesthesia resulting from a familial cryofibrinogen precipitating at 35 degrees C

Transient nephrotic syndrome, haematuria, and cryofibrinogenuria in a child after anaesthesia were found in association with a plasma cryofibrinogen that precipitated at 35 degrees C. Investigation of the family showed this to be a familial trait probably with dominant inheritance.

Thrombin-induced fibrinopeptide B release from normal and variant fibrinogens: influence of inhibitors of fibrin polymerization

Thrombin preferentially cleaves fibrinopeptides A (FPA) from fibrinogen resulting in the formation of desAA-fibrin from which most of the fibrinopeptides B (FPB) are then released with an enhanced rate. Kinetics of fibrinopeptide release from normal and dysfunctional fibrinogens were investigated in order to further characterize the mechanism of accelerated FPB release during desAA-fibrin polymerization. Dysfunctional fibrinogens London I and Ashford, exhibiting primary polymerization abnormalities (i.e., an abnormality present when all fibrinopeptides have been cleaved), which in the case of fibrinogen London I is believed to be caused by a defect in the D-domain, were shown to exhibit a decreased rate of FPB release compared with normal fibrinogen. While Gly-Pro-Arg-Pro, an inhibitor of fibrin polymerization, was shown to decrease the rate of FPB release from normal fibrinogen by a factor of 5, normal fragment D1, although inhibiting clot formation of normal fibrinogen, did not influence the acceleration of FPB release. On the other hand, the presence of fragment D1 did not enhance FPB release from fibrinogen London I, suggesting that interaction of D-domains in functional isolation with desAA-fibrin E-domains is not sufficient to enhance FPB release. Although clot formation was inhibited by the concentrations of fragment D1 used, the formation of small desAA-fibrin oligomers was hardly affected. Thus, small fibrin polymers, but not desAA-fibrin monomers, act as optimal substrates for the release of FPB by thrombin.

A new genetic fibrinogen variant (fibrinogen Erfurt I). Structurally characterized by an abnormal B beta-chain and present both in plasma and platelets

An abnormal fibrinogen was discovered in the plasma of a clinically asymptomatic woman. This fibrinogen variant was analyzed by high resolution two-dimensional gel electrophoresis and its molecular abnormality established consisting in a slight decrease in molecular mass of the B beta-chains. Analysis of fibrin revealed that cleavage of fibrinopeptide B by thrombin is normal, the molecular defect being confined to the beta-portion of the B beta-chain. The same fibrinogen variant was detected in the blood platelets of the proposita. This finding supports the assumption of a common origin of plasma and platelet fibrinogen pools. Family studies revealed the presence of the abnormal fibrinogen in a brother of the proposita, thus confirming the genetic nature of the observed variant. The underlying mutant gene occurs in both carriers in heterozygous state.

Fibrinogen Birmingham: a heterozygous dysfibrinogenemia (A alpha 16 Arg----His) containing heterodimeric molecules

Fibrinogen was isolated from the plasma of a 25-year-old female with a history of mild bleeding and several recent moderate to severe hemorrhagic episodes. Coagulability with thrombin approached 100% and varied directly with the time of incubation with the enzyme. High-performance liquid chromatography analysis of thrombin-induced fibrinopeptide release demonstrated retarded fibrinopeptide A (FPA) and fibrinopeptide B (FPB) release and the presence of an abnormal A peptide (FPA) amounting to 50% of the total. The same biochemical abnormalities were found in her asymptomatic father. Amino acid analysis and carboxypeptidase digestion of FPA demonstrated the substitution of His for Arg at A alpha 16. In contrast to the thrombin- and reptilase-sensitive Arg-Gly bond in the normal A alpha chain, the abnormal A alpha chain (A alpha) sequence is resistant to reptilase attack but is slowly cleaved by thrombin. To evaluate whether Birmingham A alpha and A alpha chains had been assembled nonselectively into heterodimeric (ie, 50% A alpha, A alpha) and homodimeric (ie, 25% A alpha, A alpha; 25% A alpha, A alpha) species, the clot and the clot liquor resulting from reptilase treatment of normal or Birmingham fibrinogen were separated, and each was then further incubated with thrombin to release remaining fibrinopeptides. Assuming that fibrinogen Birmingham contained heterodimeric molecules and that these and the normal molecules were completely incorporated into a reptilase clot, the expected coagulability would be 75%. In addition, subsequent thrombin treatment of the reptilase clot would release 50% of the total FPA and 75% of the total FPB present in the original sample. On the other hand, if only homodimeric fibrinogen species (50% A alpha, A alpha; 50% A alpha, A alpha) existed, the maximum reptilase coagulability would be 50%, and after thrombin treatment, 50% of the total FPB and no FPA would be recovered from the reptilase clot. We found the propositus's fibrinogen to be 68% coagulable, and we recovered 45% of the FPA and 70% of the FPB from the reptilase clot. Essentially the same coagulability and distribution of fibrinopeptides was found in the reptilase clot from her father's fibrinogen. We therefore conclude that fibrinogen Birmingham contains heterodimeric species (A alpha, A alpha) amounting to approximately 50% of the circulating fibrinogen molecules. The existence of heterodimers is consistent with a nonselective intracellular process of constituent chain assembly of dimeric plasma fibrinogen molecules.

Fibrinogen giessen I: a congenital homozygously expressed dysfibrinogenemia with A alpha 16 Arg----His substitution

Clinical reports are published for only two patients with homozygously expressed congenital dysfibrinogenemia. The patients, both of whom have a bleeding diathesis, have amino acid substitutions in the fibrinogen molecule at A alpha 16 Arg----Cys and A alpha 19 Arg----Ser, respectively. We report that a third patient with dysfibrinogenemia (fibrinogen Giessen I) is homozygous for A alpha 16 Arg----His. Although this patient has had excessive postpartum bleeding, she has had normal hemostasis throughout several minor surgical procedures and hysterectomy. Elucidation of the amino acid alterations in patients with dysfibrinogenemia may expand our understanding of structural determinants of fibrinogen that are critical to its function in vivo.

ADP-induced platelet aggregation depends on the conformation or availability of the terminal gamma chain sequence of fibrinogen. Study of the reactivity of fibrinogen Paris 1

Fibrinogen Paris I contains a mutant gamma chain that is longer than the normal chain, resulting in altered fibrin polymerization and cross-linking. Because these functions involve the carboxy-terminal region of the gamma chain, we decided to determine whether fibrinogen Paris I or the isolated Paris I gamma chain supports normal ADP-induced platelet aggregation, a function that requires the ultimate 12 residues of the normal gamma chain (400 through 411). Aggregation of ADP-stimulated normal platelets was defective with fibrinogen Paris I and markedly depressed with the gamma Paris I chain. These findings prompted us to characterize the carboxy-terminal structure of the region of the gamma Paris I chain responsible for this activity. The carboxy-terminal cyanogen bromide (CNBr) peptide of the normal gamma chain (385 through 411) or that from gamma Paris I was isolated by differential adsorption to triethylene-tetramine resin or by reverse-phase high-performance liquid chromatography (HPLC). The CNBr peptide from the Paris I gamma chain was identical to that of the normal gamma chain in its retention time on HPLC, its amino acid composition, and its sequence. Thus, the primary structure of the gamma Paris I chain from residue 384 through 411 is normal, indicating that a peptide insertion has occurred upstream from residue 384, resulting in an impairment of those physiologic functions attributable to the carboxy-terminal end of the gamma chain from position 384 (ie, cross-linking, ADP-induced platelet aggregation, and at least a portion of the gamma chain polymerization site). These observations demonstrate that the gamma chain platelet recognition site in the fibrinogen molecule is necessary but not alone sufficient to support normal ADP-induced platelet aggregation. There appears to be an additional requirement for normal conformation of the gamma chain or availability of its terminal sequence during the interaction of fibrinogen with platelets.

Fibrinogen Aarhus and factor XIII induced polymerization and gel formation

Fibrinogen Aarhus is an abnormal fibrinogen for which the clotting time with thrombin is greatly prolonged both in plasma and in the isolated fibrinogen. The whole blood clotting time is only slightly prolonged. The patient with this fibrinogen has no bleeding tendency. In this report we have investigated fibrinogen Aarhus in two alternative, thrombin independent polymerization and gelation pathways. These pathways are the factor XIII dependent oligomerization and gelation of fibrinogen, and heteropolymer (fibrinogen-fibronectin) formation which also is catalysed by factor XIII. Both of these reactions are qualitatively the same in fibrinogen Aarhus as in normal fibrinogen, but the rate of oligomerization is somewhat slower in fibrinogen Aarhus. This may depend on impaired association between factor XIII and fibrinogen Aarhus.

Fibrinogens Kawaguchi and Osaka: an amino acid substitution of A alpha arginine-16 to cysteine which forms an extra interchain disulfide bridge between the two A alpha chains

Structural analyses of fibrinogens from patients with congenital dysfibrinogenemia, designated as fibrinogens Kawaguchi and Osaka, have been performed to identify the difference responsible for the lack of fibrinopeptide A release. For the structural studies, a new strategy was employed. Amino acid sequence analysis of one of the lysyl endopeptidase-peptides isolated from the abnormal fibrinogens indicated that in both fibrinogens, arginine-16 of the A alpha chain had been replaced by cysteine. To characterize the chemical nature of the sulfhydryl group of cysteine-16, a tryptic peptide containing cysteine-16 of the A alpha chain was prepared from intact fibrinogen Kawaguchi. The amino acid composition and the molecular weight determination of this aberrant peptide revealed that it was a dimeric NH2-terminal peptide corresponding to residues 1-19 derived from the abnormal A alpha chain. These results indicate that the half-cystine at position 16 in the abnormal A alpha chain forms an intramolecular disulfide bridge with the same residue in the other abnormal A alpha chain and that fibrinogen Kawaguchi is a homo dimer composed of two identical abnormal halves.

Fibrinogen Vicenza and Genova II: two new cases of congenital dysfibrinogenemia with isolated defect of fibrin monomer polymerization and inhibitory activity on normal coagulation

Two new cases of congenital dysfibrinogenemia are presented in which defective fibrin monomer polymerization and inhibitory activity on normal coagulation were observed. They have been tentatively called fibrinogen Vicenza and Genova II. The first was discovered in a family with mild bleeding diathesis, the second in an asymptomatic family. In almost all reported cases of fibrinogens with defective fibrin monomer polymerization, additional functional or structural defects have been detected. In our cases, on the contrary, detailed investigations failed to show any other abnormality. Fibrinogen Genova II is apparently identical to fibrinogen Baltimore IV, whereas fibrinogen Vicenza is similar to fibrinogen Troyes and Genova I, but also exerts an evident inhibitory activity on normal coagulation and differs from fibrinogen Genova II and Baltimore IV showing a different kinetic pattern of fibrin monomer polymerization.

Fibrinogen Haifa: fibrinogen variant with absence of protective effect of calcium on plasmin degradation of gamma chains

The abnormal fibrinogen Haifa is characterized by the fact that calcium present during enzymatic digestion by plasmin does not protect the Haifa D gamma chain against further plasmin attack as it does in normal molecules. Since calcium binding to fibrinogen, ADP--platelet aggregation cofactor activity and gamma dimerization process induced by factor XIIIa are normal for fibrinogen Haifa, the corresponding sequences in the gamma chain are not involved. It seems rather that the anomaly resides near the gamma 302 plasmin cleavage site that is protected when calcium is bound to the gamma chain and that this affects the availability of the polymerization site located in the C terminal part of the chain.

[Recurrent exanthema in cryofibrinogenemia]

Report on a 50-year-old patient with cryofibrinogenemia, suffering from a recurrent exanthema induced by cold exposure.

Studies on the ultrastructure of fibrin lacking fibrinopeptide B (beta-fibrin)

Release of fibrinopeptide B from fibrinogen by copperhead venom procoagulant enzyme results in a form of fibrin (beta-fibrin) with weaker self-aggregation characteristics than the normal product (alpha beta-fibrin) produced by release of fibrinopeptides A (FPA) and B (FPB) by thrombin. We investigated the ultrastructure of these two types of fibrin as well as that of beta-fibrin prepared from fibrinogen Metz (A alpha 16 Arg----Cys), a homozygous dysfibrinogenemic mutant that does not release FPA. At 14 degrees C and physiologic solvent conditions (0.15 mol/L of NaCl, 0.015 mol/L of Tris buffer pH 7.4), the turbidity (350 nm) of rapidly polymerizing alpha beta-fibrin (thrombin 1 to 2 U/mL) plateaued in less than 6 min and formed a "coarse" matrix consisting of anastomosing fiber bundles (mean diameter 92 nm). More slowly polymerizing alpha beta-fibrin (thrombin 0.01 and 0.001 U/mL) surpassed this turbidity after greater than or equal to 60 minutes and concomitantly developed a network of thicker fiber bundles (mean diameters 118 and 186 nm, respectively). Such matrices also contained networks of highly branched, twisting, "fine" fibrils (fiber diameters 7 to 30 nm) that are usually characteristic of matrices formed at high ionic strength and pH. Slowly polymerizing beta-fibrin, like slowly polymerizing alpha beta-fibrin, displayed considerable quantities of fine matrix in addition to an underlying thick cable network (mean fiber diameter 135 nm), whereas rapidly polymerizing beta-fibrin monomer was comprised almost exclusively of wide, poorly anastomosed, striated cables (mean diameter 212 nm). Metz beta-fibrin clots were more fragile than those of normal beta-fibrin and were comprised almost entirely of a fine network. Metz fibrin could be induced, however, to form thick fiber bundles (mean diameter 76 nm) in the presence of albumin at a concentration (500 mumol/L) in the physiologic range and resembled a Metz plasma fibrin clot in that regard. The diminished capacity of Metz beta-fibrin to form thick fiber bundles may be due to impaired use or occupancy of a polymerization site exposed by FPB release. Our results indicate that twisting fibrils are an inherent structural feature of all forms of assembling fibrin, and suggest that mature beta-fibrin or alpha beta-fibrin clots develop from networks of thin fibrils that have the ability to coalesce to form thicker fiber bundles.