Hemostasis and fibrinolysis in patients with intermittent claudication: effects of prostaglandin E1

Why fish oil fails: a comprehensive 21st century lipids-based physiologic analysis

The medical community suffered three significant fish oil failures/setbacks in 2013. Claims that fish oil's EPA/DHA would stop the progression of heart disease were crushed when The Risk and Prevention Study Collaborative Group (Italy) released a conclusive negative finding regarding fish oil for those patients with high risk factors but no previous myocardial infarction. Fish oil failed in all measures of CVD prevention-both primary and secondary. Another major 2013 setback occurred when fish oil's DHA was shown to significantly increase prostate cancer in men, in particular, high-grade prostate cancer, in the Selenium and Vitamin E Cancer Prevention Trial (SELECT) analysis by Brasky et al. Another monumental failure occurred in 2013 whereby fish oil's EPA/DHA failed to improve macular degeneration. In 2010, fish oil's EPA/DHA failed to help Alzheimer's victims, even those with low DHA levels. These are by no means isolated failures. The promise of fish oil and its so-called active ingredients EPA / DHA fails time and time again in clinical trials. This lipids-based physiologic review will explain precisely why there should have never been expectation for success. This review will focus on underpublicized lipid science with a focus on physiology.

Prostaglandin E1 -containing nanoparticles improve walking activity in an experimental rat model of intermittent claudication

OBJECTIVES

Due to the low stability of lipid emulsions, a lipid emulsion of prostaglandin E1 (Lipo-PGE1 ) necessitates daily intravenous drip infusions. To overcome this issue, we developed nanoparticles containing PGE1 (Nano-PGE1 ). Nano-PGE1 showed a good sustained-release profile of PGE1 from the nanoparticles in vitro, which may permit a longer-lasting therapeutic effect to be achieved. We here examined the pharmacological activity of Nano-PGE1 in a rat experimental model of intermittent claudication induced by femoral artery ligation.

METHODS

The walking activity of the rat was tested on a rodent treadmill. Tissue levels of PGE1 were determined by enzyme immunoassay, and skeletal muscle angiogenesis (capillary growth) was monitored by immunohistochemical analysis.

KEY FINDINGS

PGE1 could be detected in the lesion site one day after the intravenous administration of Nano-PGE1 but not of Lipo-PGE1 . An increased accumulation of Nano-PGE1 in the lesion site compared with control (unlesioned) site was also observed. The ligation procedure reduced the walking activity, which in turn was improved by a single administration of Nano-PGE1 but not of Lipo-PGE1 . The single administration of Nano-PGE1 also stimulated angiogenesis in the skeletal muscle around the ligated artery.

CONCLUSIONS

The findings of this study suggest that Nano-PGE1 improves the walking activity of femoral artery-ligated rats through the accumulation and sustained release of PGE1 .

Fatal basilar artery occlusion under dabigatran occurring 13 days after femoral embolectomy

A male with atrial fibrillation for 30 years underwent embolectomy in his right leg at age 78 years. Postoperatively, he received enoxaparin 60 mg/twice a day (bid), and on day 5, phenprocoumon was started. The patient's son, a general practitioner, changed phenprocoumon to dabigatran 110 mg/bid on day 8. Pain in his left calf induced readmission after 5 days. International normalized ratio was 2.5 and D-dimer was 20 μg/mL. Dabigatran was stopped and dalteparin 5000 International Units/bid and 40 μg alprostadil infusions were started. After 8 hours, he became comatose due to basilar artery occlusion and eventually died. This tragic case raises the issue of postoperative use of dabigatran, a recently introduced thrombin inhibitor.

Effect of prostaglandin E1 on TNF-induced vascular inflammation in human umbilical vein endothelial cells

Prostaglandin E1 (PGE1) is a member of the prostaglandins and has a variety of cardiovascular protective effects. Increasing attention has been paid to the anti-inflammation activity of PGE1, but little direct evidence has been found. We investigated the effects of PGE1 on cell adhesion and inflammation and the mechanisms responsible for this activity in tumor necrosis factor (TNF)-treated human umbilical vein endothelial cells. Results demonstrated that pretreatment with PGE1 decreased the adhesion between vascular endothelial cells and monocytes, reduced the expression of vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and E-selectin in vascular endothelial cells. In addition, PGE1 suppressed TNF-induced NF-kappaB activation and production of reactive oxygen species. We concluded that PGE1 suppressed the vascular inflammatory process, which might be closely related to the inhibition of reactive oxygen species and NF-kappaB activation in human umbilical vein endothelial cells.

Protective effects of prostaglandin E1 on human umbilical vein endothelial cell injury induced by hydrogen peroxide

AIM

To investigate the protective effects of prostaglandin E(1) (PGE(1)) against H(2)O(2)-induced oxidative damage on human umbilical vein endothelial cells (HUVECs).

METHODS

HUVECs were pretreated with PGE(1) (0.25, 0.50, and 1.00 micromol/L) for 24 h and exposed to H(2)O(2) (200 micromol/L) for 12 h, and cell viability was measured by the MTT assay. LDH, NO, SOD, GSH-Px, MDA, ROS, and apoptotic percentage were determined. eNOS expression was measured by Western blotting and real-time PCR.

RESULTS

PGE(1) (0.25-1.00 micromol/L) was able to markedly restore the viability of HUVECs under oxidative stress, and scavenged intracellular reactive oxygen species induced by H(2)O(2). PGE(1) also suppressed the production of lipid peroxides, such as MDA, restored the activities of endogenous antioxidants including SOD and GSH-Px, and inhibited cell apoptosis. In addition, PGE(1) significantly increased NO content, eNOS protein, and mRNA expression.

CONCLUSION

PGE(1) effectively protected endothelial cells against oxidative stress induced by H(2)O(2), an activity that might depend on the up-regulation of NO expression.

Regulation of endothelial progenitor cells by prostaglandin E1 via inhibition of apoptosis

Bone marrow derived endothelial progenitor cells (EPC) improve endothelial function and neoangiogenesis. Prostaglandin E1 (PGE1) is used for the treatment of patients with peripheral artery disease (PAD). However, the molecular effects are only partially understood. Treatment of C57/Bl6 mice with PGE1, 10 microg/kg BW increased the number of circulating Sca-1/VEGFR-2 positive EPC in the blood compared to vehicle (122+/-7% and 119+/-6% after 10 and 20 days). EPC in the bone marrow were upregulated to 125+/-11% (10 days) and 142+/-15% (20 days). PGE1 increased DiLDL/Lectin positive spleen-derived EPC to 170+/-20% and 174+/-14% after 10 and 20 days. Treatment with PGE1 enhanced in-vivo neoangiogenesis by 2-fold (disk assay, 218+/-27%). PGE1 enhanced the SDF-1 induced migratory capacity per number of EPC to 140+/-11%, 146+/-22% and 160+/-16% after 10, 14 and 20 days. Greater migratory capacity was associated with upregulation of expression of telomere repeat-binding factor (TRF2). EPC of PGE1-treated mice were characterized by reduced apoptosis. Similarly, PGE1 prevented H(2)O(2)-induced apoptosis in cultured human EPC. The effect is mediated by PI3-kinase. The effects of PGE1 on EPC were completely prevented by co-treatment with the NO-inhibitor L-NAME, 50 mg kg(-1) p.o. Treatment with the prostaglandin I2 derivative iloprost (10 microg/kg BW, 20 days) did not alter EPC numbers or function. Physical exercise is the basis of the treatment of patients with PAD. Voluntary running increased EPC numbers in mice. Treatment with PGE1 resulted in an additional increase of Sca-1/VEGFR-2- and DiLDL/lectin positive EPC as well as migration. n=10-24 for all groups, all effects p<0.05. In summary, prostaglandin E1 increases the number of EPC in the blood and the bone marrow in mice. The effect is additive to physical exercise, depends on nitric oxide and is characterized by reduction of PI3-kinase mediated apoptosis. PGE1-mediated upregulation of EPC is associated with improved EPC function and enhanced angiogenesis.

Comparison of levels of inflammatory markers and hemostatic factors in the patients with and without peripheral arterial disease

INTRODUCTION

Peripheral arterial disease is one aspect of atherosclerosis, a disease associated with both inflammation and hypercoagulability. Many recent studies have focused on the diversity of mechanisms by which inflammation can promote blood clotting. However, the relationship between plasma concentrations of inflammatory and hemostatic markers and the severity of atherosclerosis is not yet well studied. We want to determine the relations among selected D-dimer, C-reactive protein, fibrinogen, prothrombin time and serum amyloid A, and the ankle brachial index in patients with and without peripheral arterial disease.

MATERIALS AND METHODS

In a prospective cohort study, 45 consecutive patients with peripheral arterial disease of ankle brachial index<0.90, and 44 patients without peripheral arterial disease of ankle brachial index 0.90 to 1.50 were included. D-dimer, fibrinogen, C-reactive protein, serum amyloid A, and prothrombin time were measured at the recruitment.

RESULTS

Median values of serum amyloid A, D-dimer, and C-reactive protein were significantly higher in the peripheral arterial disease group than in those without peripheral arterial disease group (p<0.001). The patients with PAD had moderately higher fibrinogen levels than without PAD (p<0.01). Prothrombin time levels were normal in both groups. In multivariable regression analyses adjusting for all blood factors as well as potential confounders, patients with peripheral arterial disease, levels of serum amyloid A, and C-reactive protein showed a highly significant, inverse association with the ankle brachial index. D-dimer and fibrinogen level increase were also found to be related to lower ankle brachial index, while no association was observed between prothrombin time levels.

CONCLUSIONS

Higher C-reactive protein, serum amyloid A, and D-dimer levels are showing positive association with the presence of peripheral arterial disease. C-reactive protein and serum amyloid A levels are direct relations between the ankle brachial index and the extent of vascular inflammation.

Intravenous prostaglandin E1 reduces monocyte chemoattractant protein-1 levels in peripheral arterial obstructive disease

OBJECTIVES

Blood monocytes are the precursors of the lipid-laden foam cells that are the hallmark of early atherosclerotic lesions, and monocyte chemoattractant protein-1 (MCP-1) plays important roles in their recruitment to the vessel wall. In this study, we measured serum levels of MCP-1 in patients with peripheral arterial obstructive disease (PAOD) and investigated whether intravenous prostaglandin E1 (PGE1) treatment, which produces clinical benefits in PAOD, might decrease such levels.

METHODS

Eight patients with PAOD at Fontaine stage II to IV were treated with a daily intravenous infusion of 10 microg of PGE1 for 7 consecutive days. Blood samples before and after 7-day PGE1 treatment were used for assays of MCP-1, interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP), von Willebrand factor (vWF), and endothelin-1 (ET-1).

RESULTS

Serum MCP-1 levels in patients with PAOD were significantly higher than those in healthy control subjects (263.8 +/- 52.8 vs 136.5 +/- 15.0 pg/mL, P =.002). PGE1 administration for 7 days resulted in a significant decrease in the MCP-1 level, from 263.8 +/- 52.8 to 196.1 +/- 25.5 pg/mL (P =.02), whereas levels of IL-6, hs-CRP, and ET-1 and the activity of vWF were not affected.

CONCLUSIONS

Serum MCP-1 levels were elevated in patients with PAOD, indicating the involvement of activation of monocytes in the pathogenesis of this disorder. Parenteral administration of PGE1 appeared to decrease circulating MCP-1 levels, which might lead to the suppression of the development of atherosclerotic lesions in patients with PAOD.

Endothelial function in patients with peripheral vascular disease: influence of prostaglandin E1

Peripheral arterial occlusive disease (PAOD) is characterized by atherosclerotic lesions in large vessels and disturbances on the microcirculatory level. In the local regulation of vascular tone and microvascular perfusion, vascular endothelium plays a key role. For many years prostaglandin E1 (PGE1) has been used for the treatment of PAOD. Because PGE1 has only moderate effects on blood flow other mechanisms may be relevant for the therapeutical efficacy. The aim of our pilot study was to evaluate endothelial function in patients with PAOD and to investigate the impact of PGE1 on endothelial-dependent vasodilation in peripheral vesselsIn 8 controls and in 8 patients with PAOD stage II, endothelial-dependent vascular responses of the femoral vessels to increasing doses of acetylcholine (30,60,90 microg/min) were determined by Doppler flow velocity measurements in the common femoral artery. Furthermore, vascular reactivity was evaluated before and immediately after intravenous infusion of 30 microg PGE1/30 min in patients. Endothelial-dependent vasodilation was significantly reduced in patients with PAOD compared to control subjects. Infusion of PGE1 neither increased blood flow in the common femoral artery nor endothelium-dependent vasodilation of peripheral resistance vessels as indicated by unchanged reaction to acetylcholine. In conclusion, endothelial function is impaired in patients with PAOD. Administration of PGE1 did not increase femoral artery blood flow or improve endothelial-dependent reactivity of peripheral resistance vessels in patients with PAOD. Therefore, beneficial effects of PGE1 in peripheral vascular disease cannot be attributed to an increase in blood supply or an improvement of endothelial-dependent vasodilation.

Markers of inflammation and hypercoagulability in diabetic and nondiabetic patients with lower extremity ischemia

Lower extremity ischemia is one aspect of atherosclerosis, a disease associated with both inflammation and hypercoagulability. Many recent studies have focused on a diversity of mechanisms by which inflammation can promote blood clotting. However, it has not been proven that inflammation can actually trigger clinically relevant thrombus formation in vivo. The purpose of the study was to determine the plasma levels of markers of inflammation and their possible association with markers for coagulability with special emphasis on the difference between patients with and without diabetes. Forty-six patients, 20 diabetics and 26 without diabetes scheduled for lower extremity revascularisation were examined by preoperative blood sampling. A strong positive correlation between C-reactive protein (CRP) and fibrinogen was found, particularly in diabetics. A high fibrinogen level was not associated with other markers of hypercoagulability, Thrombin-Antithrombin (TAT), Prothrombin Fragment 1+2 (F 1+2) and D-dimer although the latter three correlated with each other. There was also a correlation between von Willebrand antigen (vWF) and CRP, also in this case the relationship was dependent on the findings in patients with diabetes. It is concluded that there is a difference between diabetic and nondiabetic patients with lower limb ischemia with the former showing stronger signs of inflammation.