Plasminogen Deficiency Research Articles

Ligneous conjunctivitis: a local manifestation of a systemic disorder?

Ligneous conjunctivitis is a descriptive term. It refers to the “woody” consistency of the pseudomembrane that usually forms on the palpebral conjunctiva of those affected. It is rare and probably only one manifestation of a multiorgan, pseudomembranous disease.1-4We report a case of ligneous conjunctivitis in which investigation revealed a plasminogen deficiency in the heterozygous range (previously reported only in association with a homozygous plasminogen deficiency). We suggest a strategy for investigating known and new cases of ligneous conjunctivitis and/or pseudomembranous disease.J AAPOS 2000;4:313-5.

Plasminogen Did Not Affect Lung Function in Surfactant-Treated Preterm Lambs

Preterm infants with respiratory distress syndrome develop fibrin-rich hyaline membranes within the alveoli and have depressed fibrinolytic activity, which is thought to be due to a relative deficiency of plasminogen. Local fibrin deposition inhibits surfactant function and amplifies inflammation. We hypothesized that plasminogen administration to surfactant-treated preterm lambs would prevent fibrin-rich hyaline membrane formation, resulting in the amelioration of lung pathology and improved lung function. We randomly treated preterm lambs (gestational age 127–129 days) with either 16 mg of lysine-plasminogen (n = 10) or saline (n = 10), and ventilated them for 5 h. There were no significant differences in physiologic measurements of lung function (ventilation efficiency index, oxygenation index, dynamic compliance, quasi-static pressure volume curve), measures of lung injury (alveolar wash protein content and ¹²⁵I-albumin recovery) or surfactant pool size. The degree and extent of bronchiolar erosion and hyaline membrane formation were similar in the two groups. Plasminogen administration did not improve lung function or prevent hyaline membrane formation in surfactant-treated lambs.

Protein C and Protein S Deficiencies Are the Most Important Risk Factors Associated with Thrombosis in Chinese Venous Thrombophilic Patients in Taiwan

The relative risks (odds ratio, OR) of various risk factors for venous thrombophilia, including sex, antithrombin III, protein C (PC), protein S (PS) and plasminogen deficiencies, and C677T homozygous mutation of methylenetetrahydrofolate reductase gene were assessed using age matched (±5 years) conditional logistic regression analysis in 116 Chinese venous thrombophilic patients (58 males; 58 females; mean age 47.5±17.7 [SD] years) and 125 healthy controls (67 males; 58 females; mean age 45.5±15.7 years). None of the patients had prothrombin G20210A and factor V Leiden mutation or an activated PC sensitivity ratio of less than 2. One hundred and five age-matched patients and 105 controls were entered in this analysis. Only PC and PS deficiencies were significantly associated with increased risk for the development of thrombosis with an OR of 10.6 95% confidence interval 2.3–49.9, P=0.0028 and 6.7 2.7–16.5, P=0.0001 , respectively. The findings of this study suggest that PC deficiency and PS deficiency are the most important risk factors for thrombosis in Chinese venous thrombophilic patients.

Plasminogen is a critical determinant of vascular remodeling in mice.

Extracellular proteolysis is likely to be a feature of vascular remodeling associated with atherosclerotic and restenotic arteries. To investigate the role of plasminogen-mediated proteolysis in remodeling, polyethylene cuffs were placed around the femoral arteries of mice with single and combined deficiencies in plasminogen and fibrinogen. Neointimal development occurred in all mice and was unaffected by genotype. Significant compensatory medial remodeling occurred in the cuffed arteries of control mice but not in plasminogen-deficient mice. Furthermore, focal areas of medial atrophy were frequently observed in plasminogen-deficient mice but not in control animals. A simultaneous deficit of fibrinogen restored the potential of the arteries of plasminogen-deficient mice to enlarge in association with neointimal development but did not eliminate the focal medial atrophy. An intense inflammatory infiltrate occurred in the adventitia of cuffed arteries, which was associated with enhanced matrix deposition. Adventitial collagen deposition was apparent after 28 days in control and fibrinogen-deficient arteries but not in plasminogen-deficient arteries, which contained persistent fibrin. These studies demonstrate that plasmin(ogen) contributes to favorable arterial remodeling and adventitial collagen deposition via a mechanism that is related to fibrinogen, presumably fibrinolysis. In addition, these studies reveal a fibrin-independent role of plasminogen in preventing medial atrophy in challenged vessels.

Screening for thrombophilic risk factors among 25 German patients with cerebral venous thrombosis.

In this study the frequency of inherited thrombophilic risk factors in a population of German CVT patients and their influence on clinical outcome were evaluated. Twenty-five patients (age 37.1 +/- 16.3 years) with CVT were screened for inherited coagulation disorders. All participants received a full clinical follow-up (mean follow-up period 4.8 +/- 6.4 years). Inherited thrombophilic risk factors were identified in 9 (36%) of the 25 patients studied. Four were found positive for the heterozygous factor V Leiden mutation, 2 were heterozygous carriers of the prothrombin-G20210A-polymorphism. APC resistance proved to be a reliable screening method for factor V Leiden mutation, whereas genetic evaluation for protein S and C deficiencies failed to demonstrate any mutations despite the identification of 1 patient with a protein C and protein S deficiency each. One patient suffered from a familial plasminogen deficiency. These 9 patients had a less favorable outcome (P < 0.05). Our results demonstrate that screening for inherited thrombophilia should be an integral part in the diagnostic work up of CVT patients. Patients with inherited coagulopathies tended to have a less favorable outcome, corroborating recommendations for a longer period of oral anticoagulation.

Role of the Pleiotropic Effects of Plasminogen Deficiency in Infection Experiments with Plasminogen-Deficient Mice

Plasminogen-deficient mice hold great promise as tools for analyzing the contribution of plasminogen activators produced by infectious agents to pathogenesis. However, the pathology caused by congenital plasminogen deficiency complicates the interpretation of infection experiments conducted with these animals. This pathology, the most prominent features of which are poor weight gain, wasting after about 60 days of age, and shortened lifespan, results from the inability of the mice to clear small fibrin thrombi. This article describes strategies for distinguishing the contribution of this pathology from the direct effects of depriving infectious agents of plasminogen. These strategies depend on the use of mouse genotypes in which the correlation of plasminogen deficiency with fibrin-dependent pathology is broken. Mice with plasminogen activator deficiencies are unable to generate plasmin and develop pathologies identical to those seen in plasminogen-deficient mice. However, unlike plasminogen-deficient mice, they do make plasminogen available to the infectious agent. Fibrinogen-deficient mice also deficient for plasminogen do not develop the pathology typical of plasminogen deficiency. These mice allow examination of plasminogen deficiency in the absence of fibrin-dependent pathology. Use of fibrinogen-deficient mice is complicated by the possibility that fibrin may be the key substrate of plasmin generated by the infectious agent.

Plasminogen deficiency perpetuates wthe activated phenotype of hepatic stellate cells after an injury

Plasminogen deficiency perpetuates wthe activated phenotype of hepatic stellate cells after an injury

Plasminogen deficiency accelerates the development of hepatic fibrosis in mice

Plasminogen deficiency accelerates the development of hepatic fibrosis in mice

Causes of venous thrombosis in fifty Chinese patients

In a whole year from July 1997 to June 1998, a total of 50 patients with sonogram-proved venous thrombosis who called on our hematology clinic consecutively entered into the study. Their mean age was 59.1 +/- 17.5 years, range 18-83 years, and 29 were male. A series of examinations were performed in order to find out the cause of venous thrombosis. These examinations included antithrombin, protein C, protein S, plasminogen, heparin cofactor II, activated protein C ratio, factor V Leiden mutation, fibrinogen, factors VIII and XII, euglobulin lysis time, 677 C-->T mutation of methylenetetrahydrofolate reductase (MTHFR), prothrombin 20210 (PT 20210) A allele mutation, lupus anticoagulant, anticardiolipin antibody, and complete blood count. Five patients (10%) were found to have malignancy; an inferior vena cava thrombosis in one patient was due to venous compression by hydronephrosis; two patients had lupus anticoagulant; two had varicose veins of legs; two had protein C deficiency; four had protein S deficiency; two had plasminogen deficiency; two had antithrombin deficiency. No activated protein C resistance, elevated factor VIII level, factor V Leiden, PT 20210 A allele or heparin cofactor II deficiency was found in the present study. Homozygous MTHFR 677 C-->T gene mutation was found in 7 patients (14%); one of them also had a plasminogen deficiency. No possible risk factor of venous thrombosis could be found in 24 patients (48%). In conclusion, malignancy and protein S deficiency were the most frequent acquired and congenital causes of venous thrombosis in the Chinese, respectively.

State-of-the-Art-Review : Combined Heterozygous Plasminogen Deficiency and Factor V Leiden Defect in the Same Kindred

Combined plasminogen deficiency and resistance to activated protein C defect (factor V Leiden) have been described in a few families and associated with a variable occurrence of thrombotic events. Here we describe a new family with thrombophilia and the presence of hypoplasminogenemia and factor V Leiden mutation. In addition, a brief review of the literature is presented. Nine patients belonging to this kindred underwent coagulation study for hereditary thrombophilia, which included plasminogen antigen and activity assays, an activated protein C resistance test, and genetic analysis for factor V Leiden mutation and for prothrombin variant 20210A. The proposita, a 40-year-old asymptomatic female with a family history of thrombotic diathesis, was affected by heterozygous plasminogen deficiency. Hypoplasminogenemia was found also in her two sisters, in one instance associated with factor V Leiden mutation. The mother was the putative carrier of hypoplasminogenemia, but she refused to be studied. The symptomatic father was heterozygous for factor V Leiden mutation, but presented with normal plasminogen levels. Among the available siblings investigated from the paternal side, resistance to activated protein C due to factor V Leiden mutation was found in three patients, one of whom experienced venous thromboembolism. Another uncle with a history of thrombotic disease showed no coagulation abnormalities. These findings together with the data from literature confirm the role of factor V Leiden as an independent risk factor for venous thromboembolism, whereas isolated hypoplasminogenemia does not seem to increase the risk for thrombosis. There is no clear evidence that the coinheritance of these two defects may be associated with an additional risk for thrombosis compared with the presence of factor V Leiden mutation alone.

Inflammatory Bowel Disease Promotes Venous Thrombosis Earlier in Life

Background: Patients with inflammatory bowel disease (IBD) may be at increased risk of having venous thromboembolism. Methods: Medical records from 1253 IBD patients attending hospital care during the years 1987-97 were studied. These patients were recruited from a population of 340,000 inhabitants. Patients with verified venous thrombosis were characterized clinically, and blood samples were examined for coagulopathy including analyses of antithrombin, plasminogen, protein C, protein S, factor V, and prothrombin mutations. As control groups we used 99 patients with verified venous thrombosis and no history of IBD and 288 volunteers with no history of thrombosis. Results: The incidence of venous thrombosis was 1.5/1000 IBD patients per year, which is comparable to the background population. The mean age was significantly lower in IBD patients than in non-IBD patients (53 versus 64 years, P = 0.0225). We found one patient with antithrombin deficiency but none with protein C, protein S, or plasminogen deficiency. Factor V mutation was as prevalent in IBD patients with thrombosis as in thrombotic non-IBD patients (27% versus 28%) and 3.0 times (95% confidence interval, 0.8-11.9) more frequent in IBD patients with thrombosis than in healthy controls. Prothrombin mutation was not detected in IBD patients with venous thrombosis. Conclusion: We found no increased incidence of venous thrombosis in IBD patients compared with a background population. However, IBD patients had venous thrombosis earlier in life than non-IBD patients. Although factor V mutation may contribute to thrombosis, IBD acts as a trigger through mechanisms that still remain unexplained.

Plasminogen deficiency leads to impaired remodeling after a toxic injury to the liver.

Cellular proliferation and tissue remodeling are central to the regenerative response after a toxic injury to the liver. To explore the role of plasminogen in hepatic tissue remodeling and regeneration, we used carbon tetrachloride to induce an acute liver injury in plasminogen-deficient (Plg(o)) mice and nontransgenic littermates (Plg(+)). On day 2 after CCl(4), livers of Plg(+) and Plg(o) mice had a similar diseased pale/lacy appearance, followed by restoration of normal appearance in Plg(+) livers by day 7. In contrast, Plg(o) livers remained diseased for as long as 2.5 months, with a diffuse pale/lacy appearance and persistent damage to centrilobular hepatocytes. The persistent centrilobular lesions were not a consequence of impaired proliferative response in Plg(o) mice. Notably, fibrin deposition was a prominent feature in diseased centrilobular areas in Plg(o) livers for at least 30 days after injury. Nonetheless, the genetically superimposed loss of the Aalpha fibrinogen chain (Plg(o)/Fib(o) mice) did not correct the abnormal phenotype. These data show that plasminogen deficiency impedes the clearance of necrotic tissue from a diseased hepatic microenvironment and the subsequent reconstitution of normal liver architecture in a fashion that is unrelated to circulating fibrinogen.

Plasma values for u-PA in children.

Urokinase-type plasminogen activator (u-PA) is one major activator of plasminogen. It is also involved in tissue remodelling, angiogenesis, cell migration, and tumour metastasis. In adults, increased u-PA levels have been identified in patients with chronic liver disease. No data exist for u-PA plasma levels in children. In the present study, u-PA plasma levels were measured by ELISA in 95 healthy children and adolescents aged 7 months to 17 years. We found a median value of 1.06 ng/ml u-PA (range 0.43-15.78 ng/ml), which is similar to that found in adults (2-20 ng/ml). No differences between males and females were recorded. In addition, we determined u-PA plasma levels of 16 patients with severe or mild type I plasminogen deficiency and found a median value of 1.06 ng/ml (range 0.69-7.7 ng/ml). Normal plasma u-PA values in healthy children and adults are virtually no different from those reported in adults.

Multicentre evaluation of combined prothrombotic defects associated with thrombophilia in childhood. Childhood Thrombophilia Study Group.

To evaluate the role of multiple established and potential causes of childhood thrombophilia, 285 children with a history of thrombosis aged neonate to 18 years (first thrombotic onset) were investigated and compared with 185 healthy peers. APC-resistance (FV:Q506), protein C, protein S, antithrombin, heparin cofactor II (HCII), histidine-rich glycoprotein (HRGP), and prothrombin (F.II), factor XII (F.XII), plasminogen, homocysteine and lipoprotein (a) (Lp(a)) were investigated. In 59% of patients investigated one thrombotic defect was diagnosed, 19.6% showed two thrombotic risk factors, while in 21.4% of children investigated no risk factor could be identified. Single defects comprised established causes of inherited thrombophilia: FV:Q506 (homozygous n = 10, heterozygous n = 69), protein C (homozygous n = 1; heterozygous n = 31), heterozygous type I deficiency states of protein S (n = 7), antithrombin (n = 7) and homocystinuria (n = 6); potentially inherited clotting abnormalities which may be associated with thrombophilia: F.XII (n = 3), plasminogen (n = 2), HCII (n = 1), increased HRGP (n = 4); new candidate risk factors for thrombophilia: elevated plasma levels of Lp(a) (n = 26), F.II (n = 1). Heterozygous FV:Q506 was found in combination with heterozygous type I deficiency states of protein C (n = 2), protein S (n = 13), antithrombin (n = 8) and HCII (n = 1), increased Lp(a) (n = 13), and once each with elevated levels of F.II, moderate hyperhomocysteinemia, fibrinogen concentrations > 700 mg/dl and increased HRGP. In addition to the association with FV:Q506, heterozygous protein C type I deficiency was combined with deficiencies of protein S (n = 2), antithrombin (n = 1), and increased Lp(a) (n = 3). One patient showed protein C deficiency along with familially increased von Willebrand factor > 250%. Besides coexistence with FV:Q506 and protein C deficiency, protein S deficiency was combined with decreased F.XII and increased Lp(a) in one subject each. Furthermore, we found combinations of antithrombin deficiency/elevated Lp(a), hyperhomocysteinemia/Lp(a), deficiency of HCII/plasminogen, and plasminogen deficiency along with increased Lp(a) each in one. Increased prothrombin levels were associated with fibrinogen concentrations > 700 mg/dl and with HCII deficiency in one child each. Carrier frequencies of single and combined defects were significantly higher in patients compared with the controls. In conclusion, data of this multicentre evaluation indicate that paediatric thromboembolism should be viewed as a multifactorial disorder.

Functional overlap between two classes of matrix-degrading proteases in wound healing

Retarded wound healing was found in mice deficient in the serine protease precursor plasminogen, as well as in wild-type mice treated with the metalloprotease inhibitor galardin, but in both cases wound closure was ultimately completed in all mice within 60 days. The expression of several matrix metalloproteases in keratinocytes migrating to cover the wound was strongly enhanced by galardin treatment. However, when plasminogen-deficient mice were treated with galardin, healing was completely arrested and wound closure was not seen during an observation period of 100 days, demonstrating that protease activity is essential for skin wound healing. The requirement for both plasminogen deficiency and metalloprotease inhibition for complete inhibition of the healing process indicates that there is a functional overlap between the two classes of matrix-degrading proteases, probably in the dissection of the fibrin-rich provisional matrix by migrating keratinocytes. Each class alone is capable of maintaining sufficient keratinocyte migration to regenerate the epidermal surface, although this function would normally be performed by both classes acting in parallel. Since there are strong similarities between the proteolytic mechanisms in wound healing and cancer invasion, these results predict that complete arrest of this latter process in therapeutic settings will require the use of inhibitors of both classes of proteases.

Treatment of hereditary and acquired thrombophilic disorders.

The treatment of hereditary and acquired thrombophilic disorders is based on an understanding of the disease pathophysiology, prevalence, associated morbidity and mortality, and available therapeutic options. Genetic mutations are identified that result in activated protein C (APC) resistance and hyperhomocyst(e)inemia. The underlying etiologies are less well-defined; however, the disorders of factor XII deficiency, dysfibrinogenemia, Wien-Penzing platelet defect, and sticky platelet syndrome (SPS) are treatable inherited thrombophilias. Antithrombin deficiency, protein C and protein S deficiencies, and plasminogen deficiency are disorders both inherited and acquired. Antiphospholipid antibodies, myeloproliferative syndromes, and Trousseau's syndrome are acquired. Treatment for acute arterial thrombosis or venous thromboembolism is the same or similar for all thrombophilic disorders. Long-term management is based on the risk of a primary or recurrent acute thrombotic event, compared with the risk of the proposed therapy. Few blinded, controlled studies are available to validate treatment recommendations. When long-term anticoagulation is advised, careful consideration should be given to the risk associated with therapy. Bleeding risk, variable efficacy, and the risk of cutaneous necrosis limit the use of warfarin. Fixed low-dose unfractionated porcine heparin and low-molecular-weight heparins (LMWH) offer significant advantages for long-term management. These recommendations are derived from an analysis of the pertinent medical literature and are expected to change with the progress of clinical and laboratory investigation.

Thrombophilic predisposition in stroke and venous thromboembolism in Danish patients.

The present study describes 403 patients with thrombosis, from a uniform ethnic and geographical background. Two-hundred-and-seven individuals had suffered mild or moderate stroke and 196 individuals suffered venous thromboembolism. We recorded levels of antithrombin, protein C and protein S, plasminogen and plasma homocysteine, and the presence of the factor V Leiden mutation, the prothrombin 20210G-->A variant, and the methylenetetrahydrofolate reductase (MTHFR) 677C-->T polymorphism. Controls for the mutation frequencies consisted of Guthrie card blood spots from a cohort of new-born babies. The cumulative prevalence of deficiencies in antithrombin, protein C, protein S or plasminogen was 2.4% in patients with stroke and 11.2% in patients with venous thrombosis. The factor V Leiden mutation was present in 11.1% of patients with stroke and 26.5% of patients with venous thrombosis, compared with 6.6% of controls (n = 4188; P < 0.05 and P < 0.0001, respectively). The prevalence of the prothrombin 20210A variant was 3.1% in patients with venous thrombosis, 1.9% in patients with stroke and 2.0% in controls (n = 500; P > 0.05). Hyperhomocysteinemia was present in 16.0% of patients with stroke and 17.6% of patients with venous thrombosis. The prevalence of the MTHFR 677T/T genotype was no different in patients with stroke (10.6%) and venous thrombosis (8.7%) than in controls (8.3%; n = 1084; P > 0.05); thus, it apparently contributed to thrombosis only via its influence on total plasma homocysteine, which was significantly increased in patients with the T/T genotype (P < 0.001). The MTHFR T/T genotype did not further increase the risk for thrombosis in carriers of the factor V Leiden mutation. Overall, thrombotic events were associated with a known risk factor in 27% of patients with stroke and 55% of patients with venous thrombosis.

Compound-Heterozygous Mutations in the Plasminogen Gene Predispose to the Development of Ligneous Conjunctivitis: Presented in part on the XIVth International Congress on Fibrinolysis and Thrombolysis, Ljubljana, June 22-26, 1998; Fibrinolysis & Proteolysis 12:20, 1998 (abstr 54, suppl 1)

Homozygous type I plasminogen deficiency has been identified as a cause of ligneous conjunctivitis. In this study, 5 additional patients with ligneous conjunctivitis are examined. Three unrelated patients (1 boy, 1 elderly woman, and 1 man) had plasminogen antigen levels of less than 0.4, less than 0.4, and 2.4 mg/dL, respectively, but had plasminogen functional residual activity of 17%, 18%, and 17%, respectively. These subjects were compound-heterozygotes for different missense mutations in the plasminogen gene: Lys19 --> Glu/Arg513 --> His, Lys19 --> Glu/Arg216 --> His, and Lys19 --> Glu/Leu128 --> Pro, respectively. The other 2 patients, a 14-year-old boy and his 19-year-old sister, who both presented with a severe course of the disease, exhibited plasminogen antigen and functional activity levels below the detection limit (<0.4 mg/dL and <5%, respectively). These subjects were compound-heterozygotes for a deletion mutation (del Lys212) and a splice site mutation in intron Q (Ex17 + 1del-g) in the plasminogen gene. These findings show that certain compound-heterozygous mutations in the plasminogen gene may be associated with ligneous conjunctivitis. Our findings also suggest that the severity of clinical symptoms of ligneous conjunctivitis and its associated complications may depend on the amount of plasminogen functional residual activity.

Human homozygous type I plasminogen deficiency and ligneous conjunctivitis.

On the basis of a questionnaire sent to the ophthalmology departments of hospitals throughout Germany, 10 patients with ligneous conjunctivitis or pseudomembranous disease, ranging in age from 1 to 71 years were identified. All 10 patients had severely reduced plasminogen levels. Genetic analysis revealed homozygous type I plasminogen deficiency (which had not previously been described in humans) in 7 patients and compound heterozygous plasminogen deficiency in 1 patient. Clear differentiation was not possible in 2 patients. Most of the parents had heterozygous plasminogen deficiency. None of the patients had experienced any episodes of thrombosis. Additionally, the following observations were made: 1) Levels of polymorphonuclear (PMN)-elastase protein were markedly elevated in 6 of 6 patients and 10 of 11 parents tested, and levels were higher in homozygotes than in heterozygotes. 2) Hereditary factor XII deficiency was found in 3 of 6 patients tested. 3) C1-inhibitor was elevated in 2 of 4 patients, prekallikrein was elevated in 1 of 4 patients, and plasminogen activator inhibitor type 1 was elevated in 1 of 4 patients. Infusions of lys-plasminogen concentrate induced pronounced fibrinolytic activity as indicated by high levels of D-dimer, increases in plasmin-antiplasmin complex and decreases in polymorphonuclear elastase. C1-inhibitor, prekallikrein and PAI-1 normalized after repeated infusions of lys-plasminogen. In contrast to dysplasminogenemia, severe type I plasminogen deficiency might be seen as a problem of extravascular space, in particular of the mucous membranes, possibly triggered by mechanically induced or inflammatory lesions of the vessels supplying the tissue.

Common Mutation of Plasminogen Detected in Three Asian Populations by an Amplification Refractory Mutation System and Rapid Automated Capillary Electrophoresis

Congenital deficiency and dysfunction of plasminogen (PLG) are associated with a mild thrombotic tendency. To facilitate the genetic diagnosis of dysPLGemia, we combined an amplification refractory mutation system and rapid automated capillary electrophoresis. Two different fluorescence-labeled PLG-specific primers for exon XV were designed so that each DNA amplified by PCR showed fluorescence of a different wavelength. Single peaks were detected for the normal and the mutant Ala601 -Thr alleles, respectively. A study of 90 normal Caucasians revealed no individuals with the mutation, whereas its gene frequency was 0.021 in Japanese. This mutation was also detected in Korean and Chinese populations at gene frequencies of 0.016 and 0.015, respectively. All of the Korean and Chinese cases with the mutation had at least one haplotype I of the PLG gene, as did most Japanese cases. The high frequency of the Ala601-Thr mutation among these Asian populations may be due to the founder effect.