Lifestyle Influences Changes in Fibrin Clot Properties Over a 10-Year Period on a Population Level.

Case-control and observational studies have provided a plausible mechanistic link between clot structure and thrombosis. We aimed to identify lifestyle, demographic, biochemical, and genetic factors that influence changes in total fibrinogen concentration and clot properties over a 10-year period in 2,010 black South Africans. Clot properties were assessed with turbidimetry and included lag time, slope, maximum absorbance, and clot lysis time. Linear mixed models with restricted maximum likelihood were used to determine whether (1) outcome variables changed over the 10-year period; (2) demographic and lifestyle variables, biochemical variables, and fibrinogen single-nucleotide polymorphisms influenced the change in outcome variables over the 10-year period; and (3) there was an interaction between the exposures and time in predicting the outcomes. A procoagulant risk score was furthermore created, and multinomial logistic regression was used to determine the exposures that were associated with the different risk score categories. In this population setting, female gender, obesity, poor glycemic control, increased low-density lipoprotein cholesterol, and decreased high-density lipoprotein cholesterol contributed to the enhanced progression to prothrombotic clot properties with increasing age. Alcohol consumption on the other hand, offered a protective effect. The above evidence suggest that the appropriate lifestyle changes can improve fibrin clot properties on a population level, decreasing cardiovascular disease risk and thus alleviate the strain on the medical health care system.

Plasminogenemia asociada a conjuntivitis leñosa / Plasminogen Deficiency and Ligneous Conjunctivitis

El artículo presenta el caso clínico de un joven de 18 años de edad sin antecedente familiares de enfermedad crónica o hereditaria, nacido a término, sin complicaciones, quien desde los dos días de vida presentó una lesión tipo masa en la conjuntiva tarsal. Inicialmente, recibió tratamiento farmacológico tópico y seguimiento por oftalmología, por conjuntivitis bilateral persistente, masas tarsales recidivantes y cataratas en ambos ojos, por lo que requirió siete intervenciones con pobre respuesta al manejo farmacológico y quirúrgico. A los seis meses de vida se le diagnosticó hidrocefalia, que requirió manejo con derivación del ventrículo peritoneal. Dada la persistencia de la sintomatología y la refractariedad al tratamiento, se ampliaron los estudios y en una junta médica se sugirió el diagnóstico de conjuntivitis leñosa asociada a alteración del plasminógeno. Este diagnóstico fue confirmado por laboratorio clínico, que mostró sus bajas concentraciones de plasminógeno en muestras tomadas con intervalos de dos meses en tres ocasiones: 16,9%, 11,1%, 18,6% (valores de referencia: 70-150%). Se le indicó heparina de bajo peso molecular antes de procedimientos quirúrgicos mayores y triamcinolona tópica según síntomas oculares.

We present a case of an 18-year-old patient without a family history of ocular disease, born full term without complications, within his first 2 days a mass in the tarsal conjunctiva appeared. Initially he received topical treatment and follow-up by the ophthalmology department with a diagnosis of persistent bilateral conjunctivitis, relapsing tarsal masses and cataracts in both eyes requiring a total of 7 surgical interventions with a poor response. At the age of 6 months he was diagnosed with hydrocephalus and required a ventricular-peritoneal shunt. Giren the persistence of the symptoms, further studies were made and a medical board made the diagnosis of ligneous conjunctivitis associated to low levels of plasminogen. The diagnosis was confirmed by decreased levels of plasminogen in serum measured three times with 2 months intervals: 16.9%, 11.1%, 18.6% (reference valúes 70'150%). Low molecular weight heparin was ordered before surgical procedures, and topical triamcinolone applied according to ocular symptoms.

A classification of the fibrin network structures formed from the hereditary dysfibrinogens.

OBJECTIVE: The main objective was to study the relationships of the molecular defects in 38 dysfibrinogens with their fibrin networks. METHODS AND RESULTS: Scanning electron microscopic analyses revealed that all the fibrins formed under the same conditions had networks composed of either normal thickness fibers or thin fibers, accompanied by a variety of alterations in the network structure and characteristics. We classified these fibrin networks into five classes, designated normal, less-ordered, porous A, porous B and lace-like networks. The dysfibrinogens with defects in fibrinopeptide A release or the E:D binding sites formed normal or less-ordered networks, while those with defects in the D:D association formed porous A networks composed of many tapered terminating fibers, despite having fibers of normal width, and containing many pores or spaces. The porous B and lace-like networks were composed of highly branched thin fibers because of defects in the lateral association among protofibrils, and the major difference between them was the porosity of the porous B networks. All the porous B networks were easily damaged by mechanical stress, whereas the lace-like networks retained high resistance to such stress, indicating that the network strength was not dependent on the fiber width, but on the porosity that led to fragility of the network. CONCLUSION: Impairment of the D:D association is the major disturbing factor that leads to the formation of porous fibrin networks. The porosity may be introduced by severe impairment of the D:D association, as well as the lateral association, as has often been observed by extra glycosylation or defects in Ca2+ binding.