Plants and their active compounds: natural molecules to target angiogenesis

Angiogenesis, or new blood vessel formation, is an important process in the pathogenesis of several diseases and thus has been targeted for the prevention and treatment for many disorders. However, the anti-angiogenic agents that are currently in use are mainly synthetic compounds and humanized monoclonal antibodies, which are either expensive or toxic, thereby limiting their use in many patients. Therefore, it is necessary to identify less toxic, inexpensive, novel and effective anti-angiogenic molecules. Several studies have indicated that natural plant products can meet these criteria. In this review, we discuss the anti-angiogenic properties of natural compounds isolated from plants and the molecular mechanisms by which these molecules act. Finally, we summarize the advantages of using plant products as anti-angiogenic agents. Compared with currently available anti-angiogenic drugs, plant products may not only have similar therapeutic potential but are also inexpensive, less toxic, and easy to administer. However, novel and effective strategies are necessary to improve their bioavailability for clinical use.     

HIF inhibitors for ischemic retinopathies and cancers: options beyond anti-VEGF therapies

Aberrant activation of the hypoxia inducible factor (HIF) pathway causing overexpression of angiogenic genes, like vascular endothelial growth factor (VEGF), is one of the underlying causes of ocular neovascularization (NV) and metastatic cancer. Consistently, along with surgical interventions, a number of anti-VEGF agents have been approved by FDA for the treatment of ocular neovascular diseases. These anti-VEGF agents, like ranibizumab/lucentis, have revolutionized the treatment in the past decade. However, substantial vision improvement is observed only in a subset of age-related macular degeneration patients receiving ranibizumab. Further, all current therapies are associated with limitations and side effects. For example, surgeries cause tissue destruction and inflammation while anti-VEGF therapies are expensive, require repeated administration, and offer temporary relief from vascular leakage. These factors impose significant cost and treatment burdens to both the patient and society. With an aging population in most western countries with a continually increasing number of patients on lifelong treatment for these retinal diseases, the focus of ocular drug development for neovascular diseases will be to improve efficacy while reducing treatment costs. Blocking the HIF pathway, a major regulator of ocular NV and cancer, offers an appealing therapeutic strategy. Therefore, this review summarizes HIF inhibitors that have been recently evaluated for the treatment of different cancers and ischemic retinopathies.     

Mendelian Randomization and Type 2 Diabetes

Type 2 diabetes (T2DM) is a common, complex disease that poses a substantial burden on individual and population health, but we have relatively limited understanding of its underlying pathophysiology. Observational studies have highlighted large numbers of risk factors for T2DM, some of which are modifiable through behavioural or pharmacological intervention. Determining which of these risk factors plays a causal role in the development of T2DM has been a challenge, but Mendelian randomisation (MR) studies are harnessing genetic data in population studies to offer new insights. Using evolving analytical methods, MR studies continue to address questions of causality related to T2DM, including exploring the roles of adiposity, blood lipids and inflammation. The causal roles of a number of important modifiable risk factors have been confirmed by MR studies, while the relevance of others has been called into question. As more MR studies are conducted, methods are developed and refined in order to make the most efficient and reliable use of available genetic and phenotypic data. In this review, the design and findings of some important MR studies related to T2DM are explored and their relevance for translation to clinical practice considered.     

Future Directions to Establish Lipoprotein(a) as a Treatment for Atherosclerotic Cardiovascular Disease

In both epidemiologic and genetic studies, increased levels of Lp(a) have been associated with increased risk for cardiovascular diseases as well as aortic stenosis. However, until recently, it has been difficult to lower levels of Lp(a). Diet and lifestyle have little effect on plasma levels of Lp(a) which are mainly genetically determined. Emerging therapeutic agents which have recently become available, or which are undergoing clinical trials, can significantly lower Lp(a) levels. Studies with these agents will hopefully be able to provide more direct information whether reductions in Lp(a) will reduce CVD events independently of reduction in LDL-cholesterol levels.     

Predictive performance of adding platelet reactivity on top of CRUSADE score for 1-year bleeding risk in patients with acute coronary syndrome

CRUSADE (Can Rapid risk stratification of Unstable angina patients Suppress Adverse outcomes with Early implementation of the ACC/AHA guidelines) risk score can independently predict major bleeding events in patients with non-ST elevation myocardial infarction whereas the discriminative capacity is moderate. Whether adding platelet reactivity on top of CRUSADE score improves the prognostic performance for bleeding remains unclear. 512 patients with acute coronary syndrome (ACS) underwent successful percutaneous coronary intervention were enrolled and 1-year data were available. CRUSADE risk score was calculated at hospital admission and P2Y₁₂ reaction unit (PRU) value was measured by VerifyNow P2Y₁₂ assay. Thirty-five (6.8 %) patients experienced major bleeding events within 1-year follow-up. Patients who developed bleeding complications had higher CRUSADE score (37.5 ± 9.4 vs. 29.0 ± 10.2, p < 0.001) and lower PRU value (149.7 ± 57.1 vs. 196.4 ± 51.4, p < 0.001) than those did not. Both CRUSADE score and platelet reactivity were independently associated with bleeding. Kaplan–Meier analysis showed that patients with high CRUSADE score plus low platelet reactivity had significantly elevated risk for bleeding (HR 7.905, 95 % CI 2.623–23.822, p < 0.001). Compared to CRUSADE score alone, adding platelet reactivity on top of CRUSADE score offered a discriminative increment which was demonstrated by c-statistic (0.827 vs. 0.732, p = 0.011), as well as net reclassification improvement (NRI = 0.258, p < 0.001) and integrated discrimination improvement (IDI = 0.022, p = 0.002). After successful coronary stent implantation in patients with ACS, combining CRUSADE score with platelet reactivity yielded more accurate predictive value for 1-year bleeding risk.     

Detection and quantification of circulating immature platelets: agreement between flow cytometric and automated detection

Immature platelets—also termed reticulated platelets (RP)—are platelets newly released into the circulation, and have been associated with a variety of pathological thrombotic events. They can be assessed by flow cytometry after staining with thiazole orange (TO) or by using a module added to a fully automated analyzer that is currently in wide clinical use and expressed as a fraction of the total platelet count (IPF). We sought to assess the correlation and agreement between these two methods. IPF was measured using Sysmex XE 2100—and at the same time point- we used TO staining and flow cytometry to measure RP levels. Two different gates were used for the flow cytometry method, 1 and 0.5 %. Measurements from the automated analyzer were then compared separately to measurements performed using each gate. Agreement between methods was assessed using Bland–Altman method. Pearson’s correlation coefficient was also calculated. 129 subjects were enrolled and stratified into 5 groups: (1) Healthy subjects, (2) End stage renal disease, (3) Chronic stable coronary artery disease, (4) Post Coronary artery bypass surgery, (5) Peripheral thrombocytopenia. Median IPF levels were increased for patients in groups 2, 3, 4 and 5 (4.0, 4.7, 4.3, and 8.3 % respectively) compared to healthy subjects (2.5 %) p = 0.0001. Although the observed correlation between the two methods tended to be good in patients with high IPF values (i.e., group 5), the overall observed correlation was poor (Pearson’s correlation coefficient r = 0.27). Furthermore, there was poor agreement between the two methods in all groups. Despite the good correlation that was observed between the two methods at higher IPF values, the lack of agreement was significant.     

Home management of INR in the public health system: feasibility of self-management of oral anticoagulation and long-term performance of individual POC devices in determining INR

The home prothrombin time/international normalized ratio (PT/INR) self-management could be convenient for patients, enhancing treatment compliance and improving the quality of the oral anticoagulation. However, patient self-management (PSM) of oral anticoagulation may not be feasible for up to half of the patients due to cognitive or educational issues. In the present study, we aimed to evaluate the feasibility of a PSM program in a public health medical center that provides care for low-income patients. We also aimed to determine the accuracy of individual point-of-care devices (CoaguChek XS^®) during long-term of home manipulation. Patients’ time-in-therapeutic range (TTR) and perception of quality of life, were evaluated at scheduled study-visits to the center. Additionally, the accuracy of individual CoaguChek XS^® was evaluated in comparison to the standard automated coagulometer at scheduled study-visits to the center. Twenty-five patients were included in the PSM program. The median TTR of patients was 75 % before inclusion, 72 % at 3 months, 75 % at 6 months and 100 % at 12 months after the beginning of self-management (P = 0.14).The median DASS scores were 64, 63, 61.5 and 71.5 before inclusion and at 3, 6 and 12 months, respectively (P = 0.09). One hundred paired INR values were obtained. Correlation between INR values delivered by individual CoaguChek XS^® and the automated coagulometer was 94 % and the mean result bias was 0.07 INR units. The coefficient of correlation and the mean bias between methods was stable during 24 months of follow-up. The present study suggests that PSM is feasible for patients treated in the public health system and that the results delivered by CoaguChek XS^® have long-term reliability.     

High residual platelet reactivity (HRPR) for adenosine diphosphate (ADP) stimuli is a determinant factor for long-term outcomes in acute ischemic stroke with anti-platelet agents: The meaning of HRPR after ADP might be more prominent in large atherosclerotic infarction than other subtypes of AIS

High residual platelet activation (HRPA) after ADP stimuli has associated with recurrent vascular events in acute atherothrombosis with the use of antiplatelet agents (APAs). However, there has been little evidence supporting this association in acute ischemic stroke (AIS). In this study, we evaluated the influences of HRPR after ADP stimuli on the 1-year incidence of recurrent cardiovascular events and mortality in AIS with APAs. We conducted an observational, referral center cohort study on 968 AIS patients with APAs from January 2010 to December 2013 who were evaluated using optical platelet aggregometry (OPA). All patients received the dual APA combination of aspirin and clopidogrel or aspirin alone. We evaluated their platelet function 5 days after hospital admission using OPA. HRPR after ADP stimuli was defined as platelet aggregation of 70 % or greater according to OPA after 10 µM ADP stimuli. The primary endpoint was a composite of all causes of death, myocardial infarction, and stroke at the 1-year follow-up. The secondary endpoints were each component of the primary endpoint. The event rate of primary endpoint was 11.3 % (109/968). Its rate was significantly higher in the patients with HRPR (16.7 %) than in those without (9.7 %). HPRP was independently associated with the primary endpoint (OR = 1.97, CI 1.22–3.18, p < 0.01). According to the AIS subtype, the presence of HRPR was independently significant for the occurrence of the primary endpoint in the large artery atherosclerosis (LAA) subtype only (OR = 2.26, CI 1.15–4.45, p = 0.02). In this study, the presence of HRPR after ADP stimuli is associated with a poor long-term outcome after acute ischemic stroke. In particular, the influence of this factor might be more prominent in LAA compared with other types of AIS.     

Thromboinflammatory response and predictors of outcomes in patients undergoing transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) has been increasingly used to treat patients with symptomatic aortic stenosis. Despite improvements in valve deployment, patients that have undergone TAVR are at high risk for major adverse events following the procedure. Blood cell numbers, platelet function, and biomarkers of systemic inflammation were analyzed in 58 patients undergoing TAVR with the Edward’s SAPIEN valve. Following valve deployment, platelet count and agonist-induced platelet activity declined and plasma markers of systemic inflammation (interleukin-6 and S100A8/A9) increased. Baseline platelet activity prior to TAVR correlated with perioperative changes plasma interleukin-6 levels. Moreover, perioperative changes in plasma inflammatory markers predicted the decline in platelet count in the days following the TAVR procedure. Additionally, a significant effect of gender on platelet count following TAVR and was observed. Finally, post-procedural mortality was associated with sustained thrombocytopenia after TAVR. Our findings suggest that TAVR elicits a thromboinflammatory state that may contribute to post-procedural thrombocytopenia. Importantly, our results add to the growing body of literature that suggests the thromboinflammatory changes that occur early after TAVR may predict long-term outcomes.