Fibrinogen metabolism in the lungs

Fibrinogen and albumin synthesis rates in major upper abdominal surgery

Plasma fibrinogen and albumin concentrations initially decrease after abdominal surgery. On postoperative days 3-5 fibrinogen concentration returns to the preoperative level or even higher, while albumin stays low. It is not known if these altered plasma concentrations reflect changes in synthesis rate, utilization, or both. In particular a low albumin plasma concentration has often been attributed to a low synthesis rate, which is not always the case. The objective of this study was to determine fibrinogen and albumin quantitative synthesis rates in patients undergoing major upper abdominal surgery with and without intact liver size. Patients undergoing liver or pancreatic resection (n = 9+6) were studied preoperatively, on postoperative days 1 and 3-5. De novo synthesis of fibrinogen and albumin was determined; in addition, several biomarkers indicative of fibrinogen utilization were monitored. After hemihepatectomy, fibrinogen synthesis was 2-3-fold higher on postoperative day 1 than preoperatively. On postoperative days 3-5 the synthesis level was still higher than preoperatively. Following major liver resections albumin synthesis was not altered postoperatively compared to preoperative values. After pancreatic resection, on postoperative day 1 fibrinogen synthesis was 5-6-fold higher than preoperatively and albumin synthesis 1.5-fold higher. On postoperative days 3-5, synthesis levels returned to preoperative levels. Despite decreases in plasma concentrations, de novo synthesis of fibrinogen was markedly stimulated on postoperative day 1 after both hemihepatectomies and pancreatectomies, while de novo albumin synthesis remained grossly unchanged. The less pronounced changes seen following hepatectomies were possibly related to the loss of liver tissue.

Inflammatory markers in blood and exhaled air after short-term exposure to cooking fumes

Objectives:

Cooking fumes contain aldehydes, alkanoic acids, polycyclic aromatic hydrocarbons, and heterocyclic compounds. The inhalation of cooking fumes entails a risk of deleterious health effects. The aim of this study was to see if the inhalation of cooking fumes alters the expression of inflammatory reactions in the bronchial mucosa and its subsequent systemic inflammatory response in blood biomarkers.

Methods:

Twenty-four healthy volunteers stayed in a model kitchen on two different occasions for 2 or 4h. On the first occasion, there was only exposure to normal air, and on the second, there was exposure to controlled levels of cooking fumes. On each occasion, samples of blood, exhaled air, and exhaled breath condensate (EBC) were taken three times in 24h and inflammatory markers were measured from all samples.

Results:

There was an increase in the concentration of the d-dimer in blood from 0.27 to 0.28mg ml^–1 on the morning after exposure to cooking fumes compared with the levels the morning before (P-value = 0.004). There was also a trend of an increase in interleukin (IL)-6 in blood, ethane in exhaled air, and IL-1β in EBC after exposure to cooking fumes. In a sub-analysis of 12 subjects, there was also an increase in the levels of ethane—from 2.83 parts per billion (ppb) on the morning before exposure to cooking fumes to 3.53 ppb on the morning after exposure (P = 0.013)—and IL-1β—from 1.04 on the morning before exposure to cooking fumes to 1.39 pg ml^–1 immediately after (P = 0.024).

Conclusion:

In our experimental setting, we were able to unveil only small changes in the levels of inflammatory markers in exhaled air and in blood after short-term exposure to moderate concentrations of cooking fumes.

Association between fibrinogen plasma levels and platelet counts in an outpatient population and in patients with coronary heart disease

Although numerous studies concern fibrinogen (FBG) associations, the relationship between platelet (PLT) count and FBG plasma levels has yet to be completely investigated. The present study concerns the association between FBG plasma levels and PLT count in 5891 patients (2831 men and 3060 women) attending our outpatients' laboratory. Of these, a subgroup of 4116 patients (1899 men and 2217 women) with normal values of the parameters investigated was selected. A group of 170 patients with coronary heart disease was also included. The parameters studied were FBG, PLT count, leukocyte count and age. Our results showed that, in the outpatient population, FBG was significantly correlated with the PLT count (P < 0.000001) and, as previously reported, with the leukocyte count and age. In the patients with coronary heart disease, there was a significant correlation between FBG and PLT count (P < 0.000001), to be considered very significant considering the limited number of patients, whereas no correlation with age or leukocyte count was found. The role of interleukin-6, both in FBG and PLT production, is well known and may explain the correlation between these two parameters. The association of FBG and PLT count has yet to be fully investigated in epidemiological studies, even though they play an important role as two of the major contributors to the pathogenesis and evolution of cardiovascular diseases.

Antithrombin III metabolism in the pulmonary vessel endothelium

In 85 patients undergoing aorto-coronary bypass for atherosclerotic coronary disease, we measured the antithrombin III activity levels and the thrombin-antithrombin III complex concentrations in blood from the pulmonary and the radial arteries, taken before the aorto-coronary bypass procedure, with the aim of investigating the role of the pulmonary endothelium in the metabolism of the inhibitor. Results showed significantly lower mean antithrombin III activity levels, expressed as a percentage of normal plasma, in blood from the radial artery with respect to levels from the pulmonary artery (0.78 +/- 0.12 versus 0.80 +/- 0.12, P<0.0001), while no significant difference was found in thrombin-antithrombin III complex concentrations. The results seem to show that the pulmonary endothelium contributes to the antithrombin III metabolism with a 0.023 breakdown rate, corresponding to about a 0.1 fraction of the reported 0.22-0.25 total body catabolic rate, as well as the pulmonary endothelial surface (50-70 m2) corresponding to about a 0.1 fraction of the peripheral vessels' endothelial surface (500-700 m2). The data support the hypothesis of a main endothelial catabolism of antithrombin III.