Differential effects of estrogens and progestins on the anticoagulant tissue factor pathway inhibitor in the rat

Proteomic and Bioinformatic Analysis of Decellularized Pancreatic Extracellular Matrices

Tissue microenvironments are rich in signaling molecules. However, factors in the tissue matrix that can serve as tissue-specific cues for engineering pancreatic tissues have not been thoroughly identified. In this study, we performed a comprehensive proteomic analysis of porcine decellularized pancreatic extracellular matrix (dpECM). By profiling dpECM collected from subjects of different ages and genders, we showed that the detergent-free decellularization method developed in this study permits the preservation of approximately 62.4% more proteins than a detergent-based method. In addition, we demonstrated that dpECM prepared from young pigs contained approximately 68.5% more extracellular matrix proteins than those prepared from adult pigs. Furthermore, we categorized dpECM proteins by biological process, molecular function, and cellular component through gene ontology analysis. Our study results also suggested that the protein composition of dpECM is significantly different between male and female animals while a KEGG enrichment pathway analysis revealed that dpECM protein profiling varies significantly depending on age. This study provides the proteome of pancreatic decellularized ECM in different animal ages and genders, which will help identify the bioactive molecules that are pivotal in creating tissue-specific cues for engineering tissues in vitro.

Low levels of tissue factor pathway inhibitor increase the risk of cerebral venous thrombosis

Background:

Decreased concentration of tissue factor pathway inhibitor (TFPI) is a risk factor for development of deep venous thrombosis and coronary heart disease, but there is no evidence for the relationship between TFPI and cerebral venous and sinus thrombosis (CVST). The aim of this study was to determine the level of TFPI in healthy population and in patients with CVST.

Materials and Methods:

We determined the plasma level of TFPI in 20 patients with CVST (cases) and 31 healthy volunteer subjects (as control group) by enzyme linked immunoassay method. We also examined the association between TFPI and the risk of CVST. Continuous variables were compared between groups using Student's t test, and odds ratio was calculated by multiple logistic regression analysis.

Results:

The mean TFPI was significantly lower in the CVST group compared with the control group (8.60 ± 4.05 ng/mL; 14.6 ± 8.6 ng/mL; P = 0. 005), respectively. The odds ratio for CVST associated with low (<25^th percentile) levels of TFPI was 5.429 (95% CI, 1.487-19.82, P = 0.012).

Conclusion:

Our investigation demonstrates that reduced TFPI may be one of the risk factors of CVST and associated with increasing the risk of developing CVST.

Ovariectomy differential influence on some hemostatic markers of mice and rats

Rodent ovariectomy is an experimental method to eliminate the main source of sexual steroids. This work explored for the first time the ovariectomy temporal changes induced in the hemostatic coagulation markers: prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen concentration (FIB) along with uterine weight on adult female CD1 mice and Wistar rats. Uterine weight (Uw) was assessed before ovariectomy (control), and 1, 3, 5, 7, 9, 16, and 21 days after surgery. PT, aPTT, TT and FIB were estimated the same days, using reported standard techniques. Ovariectomy decreased Uw, since day 1; and from day 10 to 21 reached the lowest values for both species. After day 1, mice hemostatic parameters changed (PT +10%, P<0.05; aPTT +53%, P<0.05; TT −24%, P<0.05; FIB +67%, P<0.05). Rats showed significant changes only in TT and FIB (TT −13%, P<0.001; FIB +65%, P<0.001). Neither mice PT, aPTT and TT, recovered control values after 21 days. In the rats from day 5 to 16 aPTT diminished (18–23%, P<0.05) recovering to control values on day 21, TT after 9 days and PT on day 16. In both species, FIB returned to its control values after 9 days. Ovariectomy differentially altered the PT hemostatic parameter of mice and rats indicating a non-equivalence among both species behaviour for experimental studies of blood coagulation.

Differential effects of synthetic progestagens on neuron survival and estrogen neuroprotection in cultured neurons

Progesterone and other progestagens are used in combination with estrogens for clinical purposes, including contraception and postmenopausal hormone therapy. Progesterone and estrogens have interactive effects in brain, however interactions between synthetic progestagens and 17β-estradiol (E2) in neurons are not well understood. In this study, we investigated the effects of seven clinically relevant progestagens on estrogen receptor (ER) mRNA expression, E2-induced neuroprotection, and E2-induced BDNF mRNA expression. We found that medroxyprogesterone acetate decreased both ERα and ERβ expression and blocked E2-mediated neuroprotection and BDNF expression. Conversely, levonorgestrel and nesterone increased ERα and or ERβ expression, were neuroprotective, and failed to attenuate E2-mediated increases in neuron survival and BDNF expression. Other progestagens tested, including norethindrone, norethindrone acetate, norethynodrel, and norgestimate, had variable effects on the measured endpoints. Our results demonstrate a range of qualitatively different actions of progestagens in cultured neurons, suggesting significant variability in the neural effects of clinically utilized progestagens.

Assessing the risk of venous thromboembolic events in women taking progestin-only contraception: a meta-analysis

OBJECTIVES

To evaluate the risk of venous thromboembolic events associated with the use of progestin-only contraception and whether that risk differs with the mode of drug delivery (oral, intrauterine, or depot injection).

DESIGN

Systematic review and meta-analysis of randomised controlled trials and observational studies.

DATA SOURCES

Pubmed, Embase, Cochrane Library, and reference lists of relevant reviews.

STUDY SELECTION

Randomised controlled trials and case-control, cohort, and cross sectional studies with venous thromboembolic outcome for progestin-only contraception reported relative to a non-hormone comparator group.

DATA EXTRACTION

Data were extracted by two independent investigators, and consensus for inclusion was reached after assessment by additional investigators.

RESULTS

Among the 2022 unique references identified by all searches, eight observational studies fulfilled inclusion criteria. A total of 147 women across all studies were diagnosed with a venous thromboembolic event while taking progestin-only contraception, and the summary measure for the adjusted relative risk of a venous thromboembolic episode for users versus non-users of a progestin-only contraceptive was, based on the random effects model, 1.03 (95% CI 0.76 to 1.39). Subgroup analysis confirmed there was no association between venous thromboembolic risk and progestin-only pills (relative risk 0.90 (0.57 to 1.45)) or a progestin intrauterine device (0.61 (0.24 to 1.53)). The relative risk of a venous thromboembolic event for users of an injectable progestin versus non-users was 2.67 (1.29 to 5.53).

CONCLUSIONS

Published data assessing the risk of venous thromboembolism in women prescribed progestin-only contraception are limited. In this meta-analysis of eight observational studies, the use of progestin-only contraception was not associated with an increased risk of venous thromboembolism compared with non-users of hormonal contraception. The potential association between injectable progestins and thrombosis requires further study.

Expression of tissue factor pathway inhibitor by endothelial cells and platelets

Tissue factor pathway inhibitor (TFPI) is a potent anticoagulant protein that abrogates the activity of the tissue factor-factor VIIa catalytic complex that activates blood coagulation in vivo. The importance of TFPI in the regulation of blood coagulation is emphasized by how its activity is modulated in human disease. Decreased TFPI activity contributes to the development of both arterial and venous thrombosis and has been implicated in the thrombotic events occurring in women using oral contraceptives and in patients with paroxysmal nocturnal hemoglobinuria. Both endothelial cells and platelets produce TFPI. Our laboratory is interested in the mechanisms for expression of TFPI on the surface of these cells to better understand how TFPI prevents intravascular thrombosis. Studies of cultured endothelial cells and human placenta have demonstrated that TFPI associates with the cell surface through a glycosyl phosphatidyinositol (GPI)-anchor in a manner that is not dependent on GAGs or altered by heparin. TFPI is not directly bound to the GPI-anchor; instead it appears to bind tightly to a GPI-anchored protein. This GPI-anchored protein appears to be necessary for proper trafficking of TFPI to the cell surface. An alternatively spliced form of TFPI, TFPIbeta, is a truncated form of TFPI that is directly attached to a GPI-anchor. However, it is not clear that human endothelial cells produce TFPIbeta. Platelets produce TFPI but not TFPIbeta. TFPI is expressed on the platelet surface following dual activation with collagen plus thrombin, but not through a GPI-anchor. Studies using mouse models of TFPI deficiency are currently being conducted in our laboratory to determine if distinct physiological functions of endothelial and platelet TFPI exist in vivo.

Estrogens, selective estrogen receptor modulators, and a selective estrogen receptor down-regulator inhibit endothelial production of tissue factor pathway inhibitor 1

Background

Hormone therapy, oral contraceptives, and tamoxifen increase the risk of thrombotic disease. These compounds also reduce plasma content of tissue factor pathway inhibitor-1 (TFPI), which is the physiological inhibitor of the tissue factor pathway of coagulation. The current aim was to study if estrogens and estrogen receptor (ER) modulators may inhibit TFPI production in cultured endothelial cells and, if so, identify possible mechanisms involved.

Methods

Human endothelial cell cultures were treated with 17β-estradiol (E2), 17α-ethinylestradiol (EE2), tamoxifen, raloxifene, or fulvestrant. Protein levels of TFPI in cell media and cell lysates were measured by an enzyme-linked immunosorbent assay, and TFPI mRNA levels were assessed by quantitative PCR. Expression of ERα was analysed by immunostaining.

Results

All compounds (each in a concentration of 10 nM) reduced TFPI in cell medium, by 34% (E2), 21% (EE2), 16% (tamoxifen), and 28% (raloxifene), respectively, with identical inhibitory effects on cellular TFPI levels. Expression of TFPI mRNA was principally unchanged. Treatment with fulvestrant, which was also associated with down-regulation of secreted TFPI (9% with 10 nM and 26% with 1000 nM), abolished the TFPI-inhibiting effect of raloxifene, but not of the other compounds. Notably, the combination of 1000 nM fulvestrant and 10 nM raloxifene increased TFPI secretion, and, conversely, 10 nM of either tamoxifen or raloxifene seemed to partly (tamoxifen) or fully (raloxifene) counteract the inhibitory effect of 1000 nM fulvestrant. The cells did not express the regular nuclear 66 kDa ERα, but instead a 45 kDa ERα, which was not regulated by estrogens or ER modulators.

Conclusion

E2, EE2, tamoxifen, raloxifene, and fulvestrant inhibited endothelial production of TFPI by a mechanism apparently independent of TFPI transcription.