Associations between plasma PAI-1 concentrations and its expressions in various organs in obese model mice

Tissue Factor Pathway-Driven Initial Thrombin Generation is Associated with Hypercoagulability in Obesity

Initial thrombin (FIIa) generated via the tissue factor (TF) pathway plays a crucial role in amplifying coagulation. There is growing evidence that the TF pathway might contribute to hypercoagulation in obesity. However, it is unclear if the initial generation of FIIa (TG) is associated with hypercoagulation in obesity due to the lack of appropriate assays. This study aims to evaluate association between TF pathway-driven initial TG and hypercoagulability in obesity.We measured the initial TG levels in plasma from male Tsumura Suzuki obese diabetes (TSOD) mice and overweight subjects using the highly sensitive TG assay. To induce initial TG, TF was added to the plasma and incubated at 37°C for up to 3 minutes. After quenching the TG, we quantified the generated FIIa by kinetically monitoring its amidolytic activity with a fluorogenic substrate.We observed that initial TG levels were significantly higher in TSOD mice (n = 31) compared with non-obese mice (n = 32). Even in the absence of exogenous TF, initial TG levels in obese mice and overweight individuals were elevated when procoagulant phospholipids were added alone. Moreover, the increased initial TG that the inhibitory anti-TF antibody abolished was detectable in reconstituted plasma including pellets prepared by high-speed centrifugation of plasma from obese mice, not in plasma supernatant. We attributed the promotion of the initial TG to the increase in procoagulant TF-bearing microvesicles in circulation. Based on the findings, measuring TF pathway-driven initial TG could be a valuable method for assessing hypercoagulability in obesity.

Supplementation with Ashitaba (Angelica keiskei) Yellow Stem Exudate Prevents Aging-Induced Thrombotic Tendencies and Systemic Inflammation Without Affecting Body Weight Gain in Mice

Angelica keiskei Koidzumi (Ashitaba) is a traditional folk medicine and health supplement in Japan. Ashitaba yellow stem exudate (AYE) contains abundant chalcones and thus has the potential to treat and prevent many pathological states such as cancer, inflammation, obesity, diabetics, thrombosis, and hypertension. Levels of plasminogen activator inhibitor 1 (PAI-1), a key regulator of the fibrinolytic system, increase with age in mouse plasma. Therefore, we aimed to determine the effects of AYE on plasma thrombotic parameters in aging mice. Long-term (52 weeks) AYE supplementation significantly decreased age-induced increases of PAI-1 in mouse plasma. Supplementation with AYE decreased levels of the acute-phase and fibrinolytic protein plasma plasminogen, and significantly decreased those of tumor necrosis factor α. These results suggested that continuous intake of AYE throughout life decreases age-induced systemic inflammation and prevents thrombotic tendencies without affecting body weight gain in aged mice. Our findings showed that supplementing diets with AYE might help to prevent thrombotic diseases in elderly individuals.

Cardiovascular resistance to thrombosis in 13-lined ground squirrels

13-lined ground squirrels (Ictidomys tridecemlineatus) enter hibernation as a survival strategy during extreme environmental conditions. Typical ground squirrel hibernation is characterized by prolonged periods of torpor with significantly reduced heart rate, blood pressure, and blood flow, interrupted every few weeks by brief interbout arousals (IBA) during which blood flow fluctuates dramatically. These physiological conditions should increase the risk of stasis-induced blood clots and myocardial ischemia. However, ground squirrels have adapted to survive repeated bouts of torpor and IBA without forming lethal blood clots or sustaining lethal ischemic myocardial damage. The purpose of this study was to determine if ground squirrels are resistant to thrombosis and myocardial ischemia during hibernation. Blood markers of coagulation, fibrinolysis, thrombosis, and ischemia, as well as histological markers of myocardial ischemia were measured throughout the annual hibernation cycle. Hibernating ground squirrels were also treated with isoprenaline to induce myocardial ischemia. Thrombin-antithrombin complex levels were significantly reduced (p < 0.05) during hibernation, while D-dimer level remained unchanged throughout the annual cycle, both consistent with an antithrombotic state. During torpor, the ground squirrels were in a hyperfibrinolytic state with an elevated ratio of tissue plasminogen activator complexed with plasminogen activator inhibitor to total plasminogen activator inhibitor (p < 0.05). Histological markers of myocardial ischemia were reversibly elevated during hibernation with no increase in markers of myocardial cell death in the blood. These data suggest that ground squirrels do not form major blood clots during hibernation through suppression of coagulation and a hyperfibrinolytic state. These animals also demonstrate myocardial resistance to ischemia.

Ashitaba (Angelica Keiskei) Exudate Prevents Increases in Plasminogen Activator Inhibitor-1 Induced by Obesity in Tsumura Suzuki Obese Diabetic Mice

Angelica keiskei koidzumi (ashitaba) is consumed as a traditional folk medicine and health food in Japan. Ashitaba extract contains abundant flavonoids containing chalcones. Plasminogen activator inhibitor-1 (PAI-1) is the primary physiological inhibitor of tissue plasminogen activator. Excessive amounts of PAI-1 in plasma disrupt the fibrinolytic balance and promote a prothrombotic state with which thrombosis and cardiovascular diseases are associated. In the present study, we investigated the effects of ashitaba yellow exudate (AE) on enhanced PAI-1 levels in Tsumura Suzuki obese diabetic (TSOD) mice. AE significantly decreased food efficiency and plasma PAI-1 in TSOD mice but did not affect lean control Tsumura Suzuki nonobese (TSNO) mice. AE also decreased some parameters in the plasma, such as glucose, insulin, tumor necrosis factor alpha (TNF-α) and gains in body weight, subcutaneous, mesenteric fat weight in TSOD mice but had little effect on these parameters in TSNO mice. Levels of adipose PAI-1 were significantly higher in TSOD than in TSNO mice. Major sources of plasma PAI-1 are thought to be adipose tissue and liver. AE significantly suppressed PAI-1 protein levels in the livers of both TSOD and TSNO mice. These results suggest that AE decreased plasma PAI-1 levels by suppressing both the adipose tissue retention of PAI-1 protein and liver PAI-1 production in TSOD mice. Supplementing the diet with AE might help to prevent thrombotic diseases or alleviate the risk of thrombotic diseases as well as to suppress metabolic state in obese individuals.

The contribution of different adipose tissue depots to plasma plasminogen activator inhibitor-1 (PAI-1) levels

Increased plasma plasminogen activator inhibitor-1 (PAI-1) level is considered a mechanistic pathway through which obesity contributes to increased cardiovascular disease risk. Abdominal adipose tissue specifically, is a major PAI-1 source with visceral adipose tissue (VAT), an ectopic fat depot, generally considered to produce more PAI-1 than subcutaneous adipose tissue. However, this does not necessarily lead to increased plasma PAI-1 levels. This review provides an overview of studies investigating the association between body fat distribution and plasma PAI-1 levels. It discusses factors that influence this relationship and also considers the contribution of other tissue to plasma PAI-1 levels, placing the relative contribution of adipose tissue into perspective. In conclusion, the relationship between VAT and plasma PAI-1 levels is not fixed but can be modulated by a number of factors such as the size of the subcutaneous adipose tissue depot, ethnicity, possibly genetics and other obesity-related metabolic abnormalities.

Perioperative Factors and Their Effect on the Fibrinolytic System in Arthroplasty Patients

BACKGROUND

Total joint arthroplasty (TJA) patients are mostly of advanced age and with comorbidities such as increased body mass index (BMI) and impaired glucose tolerance. These factors and type of surgery may affect the fibrinolytic system.

AIM

To investigate the effect of age, sex, BMI, type of surgery, and tranexamic acid (TXA) treatment on the fibrinolytic system in TJA patients.

METHODS

Ninety-nine patients undergoing TJA (32 total hip arthroplasty [THA] and 67 total knee arthroplasty [TKA]) were included in this study. Blood samples were drawn at preoperative clinic appointments and on postoperative day 1. Antigenic levels of d-dimer, plasminogen activator inhibitor 1 (PAI-1), and tissue plasminogen activator (tPA) were measured using a commercially available enzyme-linked immunosorbent assay kit. Antiplasmin activity was measured using functional method. Age, gender, hemoglobin (Hb) levels, and BMI were collected from the records.

RESULTS

Preoperative d-dimer and tPA levels were positively correlated with age, whereas preoperative antiplasmin was negatively correlated with age. Body mass index was only associated with preoperative tPA levels. There was no significant difference in postoperative levels of d-dimer, PAI-1, tPA, or antiplasmin between patients treated with TXA or without TXA. Percentage change in d-dimer and tPA showed significantly lower values in patients treated with TXA compared to the nontreated group. Type of surgery did not affect the fibrinolytic markers.

CONCLUSION

These results confirm that advanced age and elevated BMI positively contribute to fibrinolytic dysregulation in TJA patients, whereas TXA seems to decrease the fibrinolytic activity.