Mechanism of hypertension and proteinuria during angiogenesis inhibition: evolving role of endothelin-1

Hypertension toxicity of VEGFR-TKIs in cancer treatment: incidence, mechanisms, and management strategies

Vascular endothelial growth factor receptor tyrosine kinase inhibitors (VEGFR-TKIs) are a class of targeted anticancer agents that include pazopanib, sunitinib, axitinib, and others. Currently, VEGFR-TKIs are widely used in the clinical treatment of various tumors, which can prolong patients' survival and even cure tumors. However, the use of VEGFR-TKIs is frequently associated with the occurrence of cardiovascular adverse events, with hypertension being the most prevalent. Hypertension and its complications can significantly impact the prognosis of patients, potentially jeopardizing their lives and resulting in the reduction or even cessation of treatment in severe cases. This review addresses the incidence of hypertension due to VEGFR-TKIs, mechanisms of toxicity, management strategies, and future research directions. In addition, hypertension due to VEGFR-TKIs may be associated with salt sensitivity, and possible mechanisms of hypertensive side effects are vasodilator imbalance, decreased capillary density, renal injury, impaired endothelial function due to oxidative stress, decreased lymphatic vascular density, and "off-target effect". A comprehensive understanding of hypertension toxicity due to cancer treatment with VEGFR-TKIs, can enhance clinical practice, thereby improving the prognostic outcomes of VEGFR-TKIs in oncology patients.

Efficacy and safety of EGFR-TKIs in combination with angiogenesis inhibitors as first-line therapy for advanced EGFR-mutant non-small-cell lung cancer: a systematic review and meta-analysis

BACKGROUND

For patients with advanced non-small-cell lung cancer (NSCLC) with EGFR mutations, the suggested course of action is epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs). Even with a high disease control rate, a majority of patients develop acquired EGFR-TKIs resistance and eventually advance. To increase the benefits of treatment, clinical trials are increasingly exploring the value of EGFR-TKIs combined with angiogenesis inhibitors as a first-line treatment in advanced NSCLC carrying EGFR mutations.

METHOD

Using PubMed, EMBASE and Cochrane Library, to locate published full-text articles in print or online, a thorough literature search was done from the database's inception to February 2021. Additionally, oral presentation RCTs from ESMO and ASCO were obtained. We sifted out RCTs that used EGFR-TKIs along with angiogenesis inhibitors as first-line therapy for advanced EGFR-mutant NSCLC. ORR, AEs, OS, and PFS were the endpoints. Review Manager version 5.4.1 was used for data analysis.

RESULTS

One thousand eight hundred twenty-one patients were involved in 9 RCTs. According to the results, combining EGFR-TKIs with angiogenesis inhibitors therapy prolonged PFS of advanced EGFR-mutation NSCLC patients on the whole [HR:0.65 (95%CI: 0.59~0.73, P<0.00001)]. No significant statistical difference was identified between the combination group and single drug group in OS(P=0.20) and ORR (P=0.11). There are more adverse effects when EGFR-TKIs are used in combination with angiogenesis inhibitors than when used alone.

CONCLUSION

The combination of EGFR-TKIs and angiogenesis inhibitors prolonged PFS in patients with EGFR-mutant advanced NSCLC, but the OS and ORR benefit was not significant, and the risk of adverse events was higher, more pronounced with hypertension and proteinuria; PFS in subgroups suggested that the combination was associated with better PFS in the smoking, liver metastasis, and no brain metastasis groups, and the included studies suggested that the smoking group , liver metastasis group, and brain metastasis group may have a potential OS benefit.

Adverse events as potential predictive factors of therapeutic activity in patients with unresectable hepatocellular carcinoma treated with atezolizumab plus bevacizumab

AIM

To investigate the possible correlation between the development of adverse events (AEs) and prognosis in patients with unresectable hepatocellular carcinoma (HCC) treated with atezolizumab plus bevacizumab (Atez/Bev).

METHODS

A total of 286 patients with unresectable HCC treated with Atez/Bev as first-line systematic therapy were included.

RESULTS

Regarding treatment-related AEs, decreased appetite of any grade, proteinuria of any grade, and fatigue of any grade were found with a frequency of ≥20%. Multivariate analysis adjusted for immune-related liver injury, immune-related endocrine dysfunction, proteinuria, fatigue, decreased appetite, hypertension, sex, age, Eastern Cooperative Oncology Group performance status, HCC etiology, HCC stage, Child-Pugh score, and α-fetoprotein showed that hypertension of any grade (hazard ratio [HR], 0.527; 95% confidence interval [CI], 0.326-0.854; p = 0.009) and α-fetoprotein ≥100 ng/ml (HR, 1.642; 95% CI, 1.111-2.427; p = 0.013) were independently associated with progression-free survival. Multivariate analysis adjusted for the same AEs showed that fatigue (HR, 2.354; 95% CI, 1.299-4.510; p = 0.010) was independently associated with overall survival. Median progression-free survival was 6.5 months (95% CI, 5.2-8.1) in patients without hypertension of any grade and 12.6 months (95% CI, 6.7-not available) in patients with hypertension of any grade (p = 0.035). The overall survival was significantly shorter in patients in whom treatment-related fatigue of any grade was observed (p < 0.001). Regarding response rates, the disease control rate of patients who developed treatment-related hypertension (94.2%) was significantly higher than those who did not (79.1%) (p = 0.009).

CONCLUSIONS

Treatment-related hypertension is associated with good outcomes in patients with HCC treated with Atez/Bev.

The efficacy and safety of anlotinib combined with platinum-etoposide chemotherapy as first-line treatment for extensive-stage small cell lung cancer: A Chinese multicenter real-world study

Background

Patients with extensive-stage small-cell lung cancer (ES-SCLC) have high recurrence rates and bleak prognosis. This multicenter real-world study aimed to explore the efficacy and safety of anlotinib combined with platinum-etoposide chemotherapy as the first-line treatment of ES-SCLC.

Methods

Pathologically confirmed ES-SCLC patients receiving anlotinib plus platinum-etoposide chemotherapy as the first-line treatment were enrolled in this retrospective study. The primary endpoint of this study was progression-free survival (PFS), and secondary endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR), and adverse reactions. The Cox regression analyses were employed to investigate the independent prognostic factors for OS and PFS of these individuals.

Results

In total, 58 patients were included in this study. The median PFS was 6.0 months [95% confidence interval (CI): 3.5-8.5], and the median OS was 10.5 months (95%CI 8.7-12.3). Thirty-four patients achieved partial response (PR), 18 patients achieved stable disease (SD), and 6 patients achieved progressive disease (PD). The ORR and DCR were 58.6% and 89.6%. The main treatment-related adverse reactions were generally tolerated. Myelosuppression (44.8%) was the most common adverse reaction, followed by hypertension (41.4%), fatigue (34.5%), gastrointestinal reaction (32.7%), and hand-foot syndrome (24.1%). Multivariate analysis showed that post-medication hand-foot syndrome [PFS 8.5 vs. 5.5 months, Hazards Ratio (HR)=0.23, 95%CI 0.07-0.72, P =0.012] was the independent predictor of PFS, and hypertension (OS 15.9 vs. 8.3 months, HR=0.18, 95%CI 0.05-0.58, P =0.005) was the independent predictor of OS.

Conclusion

Anlotinib combined with platinum-etoposide chemotherapy as the first-line treatment for ES-SCLC appears to be effective and well-tolerated in the real-world. Well-designed large-scale prospective studies are urgently needed in the future to verify our findings.

Insights on the molecular targets of cardiotoxicity induced by anticancer drugs: A systematic review based on proteomic findings

Several anticancer agents have been associated with cardiac toxic effects. The currently proposed mechanisms to explain cardiotoxicity differ among anticancer agents, but in fact, the specific modulation is not completely elucidated. Thus, this systematic review aims to provide an integrative perspective of the molecular mechanisms underlying the toxicity of anticancer agents on heart muscle while using a high-throughput technology, mass spectrometry (MS)-based proteomics. A literature search using PubMed database led to the selection of 27 studies, of which 13 reported results exclusively on animal models, 13 on cardiomyocyte-derived cell lines and only one included both animal and a cardiomyocyte line. The reported anticancer agents were the proteasome inhibitor carfilzomib, the anthracyclines daunorubicin, doxorubicin, epirubicin and idarubicin, the antimicrotubule agent docetaxel, the alkylating agent melphalan, the anthracenedione mitoxantrone, the tyrosine kinase inhibitors (TKIs) erlotinib, lapatinib, sorafenib and sunitinib, and the monoclonal antibody trastuzumab. Regarding the MS-based proteomic approaches, electrophoretic separation using two-dimensional (2D) gels coupled with tandem MS (MS/MS) and liquid chromatography-MS/MS (LC-MS/MS) were the most common. Overall, the studies highlighted 1826 differentially expressed proteins across 116 biological processes. Most of them were grouped in larger processes and critically analyzed in the present review. The selection of studies using proteomics on heart muscle allowed to obtain information about the anticancer therapy-induced modulation of numerous proteins in this tissue and to establish connections that have been disregarded in other studies. This systematic review provides interesting points for a comprehensive understanding of the cellular cardiotoxicity mechanisms of different anticancer drugs.

Rho kinase inhibition ameliorates vascular remodeling and blood pressure elevations in a rat model of apatinib-induced hypertension

OBJECTIVES

Hypertension is one of the major adverse effects of tyrosine kinase inhibitors (TKIs) targeting vascular endothelial growth factors. However, the mechanism underlying TKIs-induced hypertension remains unclear. Here, we explored the role of the RhoA/Rho kinase (ROCK) signaling pathway in elevation of blood pressure (BP) induced by apatinib, a selective TKI approved in China for treatment of advanced or metastatic gastric cancer. A nonspecific ROCK inhibitor, Y27632, was then combined with apatinib and its efficacy in alleviating apatinib-induced hypertension was evaluated.

METHODS

Normotensive female Wistar-Kyoto rats were exposed to two different doses of apatinib, or apatinib combined with Y27632, or vehicle for 2 weeks. BP was monitored by a tail-cuff plethysmography system. The mRNA levels and protein expression in the RhoA/ROCK pathway were determined, and vascular remodeling assessed.

RESULTS

Administration of either a high or low dose of apatinib was associated with a rapid rise in BP, reaching a plateau after 12 days. Apatinib treatment mediated upregulation of RhoA and ROCK II in the mid-aorta, more significant in the high-dose group. However, ROCK I expression showed no statistically significant differences. Furthermore, the mRNA level of GRAF3 decreased dose-dependently. Apatinib administration was also associated with decreased levels of MLCP, and elevated endothelin-1 (ET-1) and collagen I, which were accompanied with increased mid-aortic media. However, treatment with Y27632 attenuated the above changes.

CONCLUSION

These findings suggest that activation of the RhoA/ROCK signaling pathway could be the underlying mechanism of apatinib-induced hypertension, while ROCK inhibitor have potential therapeutic value.

Anlotinib-Induced Hypertension: Current Concepts and Future Prospects

BACKGROUND

Anlotinib is a new tyrosine kinase inhibitor developed in China that targets the receptors for vascular endothelial growth factor, platelet-derived growth factor, fibroblast growth factor, and stem cell factor. Therefore, anlotinib inhibits tumor angiogenesis, representing a new therapeutic alternative for lung cancer. Hypertension is one of its most common adverse effects, leading to discontinuation of the drug and limited clinical usefulness.

OBJECTIVE

The present review aims to summarize the evidence on the prevalence, physiopathology, and management of anlotinib-induced hypertension, as well as its effect on the cancer prognosis.

METHOD

Searches in Medline, Cochrane Central Library, and Embase were performed using the following terms: anlotinib, adverse effect, hypertension, clinical trial, vascular endothelial growth factor, and antiangiogenic drugs. Citations were also identified by checking the reference sections of selected papers.

RESULTS

Except for a phase I clinical trial with a small sample size (n = 6), almost all the clinical trials on anlotinib have reported the development of anlotinib-induced hypertension. In these trials, the incidence of hypertension ranged from 13% to 67.7%, and that of grade 3/4 hypertension ranged from4.8% to 16%. Alterations in nitric oxide, endothelin-1, microvascular rarefaction, selective vasoconstrictions, and renal injury have been cited as potential mechanisms leading to anlotinib-induced hypertension. When needed, treatment may include general hygienic measures and pharmacotherapy in some cases.

CONCLUSIONS

To effectively manage anlotinib-induced hypertension, early prevention, a reasonable dosage regimen, and appropriate treatment are critical to effectively manage anlotinib-induced hypertension. Additionally, anlotinib-induced hypertension may be considered a marker for predicting efficacy.

Onco-hypertension: An Emerging Specialty

Cancer is one of the leading causes of death worldwide. With the introduction of newer chemotherapeutic agents, targeted therapies, and immunotherapy, the prognosis and survival of patients with cancer has remarkably improved. As a result, patients are living longer and experiencing long-term cardiovascular complications. Hypertension is an important risk factor for cardiovascular diseases. Patients with malignancy have multiple etiologies of hypertension development, worsening, or association. This is because of the complex interplay between cancer type, chemotherapeutic agent, patient age, antihypertensive agent, and preexisting comorbidities in the etiology and pathogenesis of hypertension. Management of hypertension in patients with cancer requires accurate blood pressure measurement and considering factors such as adjuvant therapy and cancer-related pain. There are no set guidelines for management of hypertension in this unique cohort, and the therapy should be individualized based on the treatment guidelines for the general population. Onco-hypertension is an emerging subspeciality and entails a multidisciplinary approach between oncology, primary care physicians, nephrology, and cardiology.

The Molecular Mechanisms of Cardiotoxicity Induced by HER2, VEGF, and Tyrosine Kinase Inhibitors: an Updated Review

AIM

In recent decades, there has been a revolutionary decrease in cancer-related mortality and an increase in survival due to the introduction of novel targeted drugs. Nevertheless, drugs targeting human epidermal growth factor receptor 2 (HER-2), angiogenesis, and other tyrosine kinases also come with unexpected cardiac side effects, including heart failure, hypertension, arterial thrombosis, and arrhythmias, and have mechanisms that are unlike those of classic chemotherapeutic agents. In addition, it is challenging to address some problems, as the existing guidelines need to be more specific, and further large-scale clinical trials and experimental studies are required to confirm the benefit of administering cardioprotective agents to patients treated with targeted therapies. Therefore, an improved understanding of cardiotoxicity becomes increasingly important to minimize the pernicious effects and maximize the beneficial effects of targeted agents.

METHODS

"Cardiotoxicity", "targeted drugs", "HER2", "trastuzumab", "angiogenesis inhibitor", "VEGF inhibitor" and "tyrosine kinase inhibitors" are used as keywords for article searches.

RESULTS

In this article, we report several targeted therapies that induce cardiotoxicity and update knowledge of the clinical evidence, molecular mechanisms, and management measures.

Hypertension: Current trends and future perspectives

Hypertension is a significant and increasing global health issue. It is a leading cause of cardiovascular disease and premature death worldwide due to its effects on end organs, and through its associations with chronic kidney disease, diabetes mellitus and obesity. Despite current management strategies, many patients do not achieve adequate blood pressure (BP) control. Hypertension-related cardiovascular mortality rates are rising in tandem with the increasing global prevalence of chronic kidney disease, diabetes mellitus and obesity. Improving BP control must therefore be urgently prioritised. Strategies include utilising existing antihypertensive agents more effectively, and using treatments developed for co-existing conditions (such as sodium-glucose cotransporter 2 inhibitors for diabetes mellitus) that offer additional BP-lowering and cardiovascular benefits. Additionally, novel therapeutic agents that target alternative prohypertensive pathways and that offer broader cardiovascular protection are under development, including dual angiotensin receptor-neprilysin inhibitors. Nonpharmacological strategies such as immunotherapy are also being explored. Finally, advancing knowledge of the human genome and molecular modification technology may usher in an exciting new era of personalised medicine, with the potential to revolutionise the management of hypertension.

Sorafenib not only impairs endothelium-dependent relaxation but also promotes vasoconstriction through the upregulation of vasoconstrictive endothelin type B receptors

As a VEGF-targeting agent, sorafenib has been used to treat a number of solid tumors but can easily lead to adverse vascular effects. To elucidate the underlying mechanism, rat mesenteric arteries were subjected to organ cultured in the presence of different concentrations of sorafenib (0, 3, 6 and 9 mg/L) with or without inhibitors (U0126, 10-5 M; SB203580, 10-5 M; SP200126, 10-5 M) of MAPK kinases, and then acetylcholine- or sodium nitroprusside-induced vasodilation and sarafotoxin 6c-induced vasoconstriction were monitored by a sensitive myograph. The NO synthetases, the nitrite levels, the endothelial marker CD31,the ETB and ETA receptors and the phosphorylation of MAPK kinases were studied. Next, rats were orally administrated by sorafenib for 4 weeks (7.5 and 15 mg/kg/day), and their blood pressure, plasma ET-1, the ETB and ETA receptors and the phosphorylation of MAPK kinases in the mesenteric arteries were investigated. The results showed that sorafenib impairs endothelium-dependent vasodilation due to decreased NO levels and the low expression of eNOS and iNOS. Weak staining for CD31 indicated that sorafenib induced endothelial damage. Moreover, sorafenib caused the upregulation of vasoconstrictive ETB receptors, the enhancement of ETB receptor-mediated vasoconstriction and the activation of JNK/MAPK. Blocking the JNK, ERK1/2 and p38/MAPK signaling pathways by using the inhibitors significantly abolished ETB receptor-mediated vasoconstriction. Furthermore, it was observed that the oral administration of sorafenib caused an increase in blood pressure and plasma ET-1, upregulation of the ETB receptor and the activation of JNK in the mesenteric arteries. In conclusion, sorafenib not only impairs endothelium-dependent vasodilatation but also enhances ETB receptor-mediated vasoconstriction, which may be the causal factors for hypertension and other adverse vascular effects in patients treated with sorafenib.

Efficacy and Safety of Anlotinib for Elderly Patients with Previously Treated Extensive-Stage SCLC and the Prognostic Significance of Common Adverse Reactions

Background

This study was to investigate the efficacy and safety of anlotinib for elderly patients with previously treated extensive-stage small cell lung cancer (ES-SCLC) and the prognostic significance of common adverse reactions.

Patients and Methods

A total of 79 elderly patients (≥60 years) with ES-SCLC who failed after at least two lines of previous systemic therapy were included. Baseline characteristics of the patients were collected. Follow-up was conducted regularly. Adverse reactions were documented. Survival curves were drawn using Kaplan–Meier method. Univariate analysis was assessed using log rank test, and multivariate analysis was adjusted by Cox regression analysis. Additionally, the prognostic significance of common adverse reactions was performed.

Results

All of the 79 patients were available for evaluation of efficacy. Partial response (PR) was observed in 7 patients, stable disease (SD) was noted in 48 patients and progressive disease (PD) was confirmed in 24 patients. Consequently, the objective response rate (ORR) was 8.9% and disease control rate (DCR) was 69.6%. The median progression-free survival (PFS) of the 79 elderly patients with ES-SCLC was 3.0 months [95% confidence interval (CI): 2.02–3.98]. The median overall survival (OS) was 7.1 months (95% CI: 5.07–9.13). Safety profile demonstrated that the relatively common adverse reactions of the elderly patients with ES-SCLC receiving anlotinib treatment were hypertension (40.5%), hand-foot syndrome (HFS, 31.6%), diarrhea (27.8%), decreased appetite (20.3%), fatigue (17.7%) and weight loss (17.7%). Interestingly, the prognostic significance of common adverse reactions indicated that the median PFS of patients with hypertension and without hypertension was 4.35 and 2.95 months, respectively (P=0.01), and the median PFS of patients with HFS and without HFS was 4.20 and 2.95 months, respectively (P=0.03).

Conclusion

The preliminary efficacy and safety of anlotinib in the treatment for elderly patients with previously treated ES-SCLC was satisfactory, and patients with hypertension and hand-foot syndrome might confer superior prognosis.

Vascular toxicity associated with anti-angiogenic drugs

Over the past two decades, the treatment of cancer has been revolutionised by the highly successful introduction of novel molecular targeted therapies and immunotherapies, including small-molecule kinase inhibitors and monoclonal antibodies that target angiogenesis by inhibiting vascular endothelial growth factor (VEGF) signaling pathways. Despite their anti-angiogenic and anti-cancer benefits, the use of VEGF inhibitors (VEGFi) and other tyrosine kinase inhibitors (TKIs) has been hampered by potent vascular toxicities especially hypertension and thromboembolism. Molecular processes underlying VEGFi-induced vascular toxicities still remain unclear but inhibition of endothelial NO synthase (eNOS), reduced nitric oxide (NO) production, oxidative stress, activation of the endothelin system, and rarefaction have been implicated. However, the pathophysiological mechanisms still remain elusive and there is an urgent need to better understand exactly how anti-angiogenic drugs cause hypertension and other cardiovascular diseases (CVDs). This is especially important because VEGFi are increasingly being used in combination with other anti-cancer dugs, such as immunotherapies (immune checkpoint inhibitors (ICIs)), other TKIs, drugs that inhibit epigenetic processes (histone deacetylase (HDAC) inhibitor) and poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors, which may themselves induce cardiovascular injury. Here, we discuss vascular toxicities associated with TKIs, especially VEGFi, and provide an up-to-date overview on molecular mechanisms underlying VEGFi-induced vascular toxicity and cardiovascular sequelae. We also review the vascular effects of VEGFi when used in combination with other modern anti-cancer drugs.

Vascular Cardio-Oncology: Vascular Endothelial Growth Factor inhibitors and hypertension

Since the formation of new blood vessels is essential for tumour growth and metastatic spread, inhibition of angiogenesis by targeting the vascular endothelial growth factor (VEGF) pathway is an effective strategy for various types of cancer, most importantly renal cell carcinoma, thyroid cancer, and hepatocellular carcinoma. However, VEGF inhibitors have serious side effects, most importantly hypertension and nephropathy. In case of fulminant hypertension, this may only be handled by lowering the dosage since the blood pressure rise is proportional to the amount of VEGF inhibition. These effects pathophysiologically and clinically resemble the most severe complication of pregnancy, preeclampsia, in which case an insufficient placenta leads to a rise in sFlt-1 levels causing a decrease in VEGF availability. Due to this overlap, studies in preeclampsia may provide important information for VEGF inhibitor-induced toxicity and vice versa. In both VEGF inhibitor-induced toxicity and preeclampsia, endothelin (ET)-1 appears to be a pivotal player. In this review, after briefly summarizing the anticancer effects, we discuss the mechanisms that potentially underlie the unwanted effects of VEGF inhibitors, focusing on ET-1, nitric oxide and oxidative stress, the renin-angiotensin-aldosterone system, and rarefaction. Given the salt sensitivity of this phenomenon, as well as the beneficial effects of aspirin in preeclampsia and cancer, we next provide novel treatment options for VEGF inhibitor-induced toxicity, including salt restriction, ET receptor blockade, and cyclo-oxygenase inhibition, in addition to classical antihypertensive and renoprotective drugs. We conclude with the recommendation of therapeutic drug monitoring to improve patient outcome.

Endothelins in cardiovascular biology and therapeutics

Cardiovascular disease is a major contributor to global morbidity and mortality and is the common end point of many chronic diseases. The endothelins comprise three structurally similar peptides of 21 amino acids in length. Endothelin 1 (ET-1) and ET-2 activate two G protein-coupled receptors - endothelin receptor type A (ET_A) and endothelin receptor type B (ET_B) - with equal affinity, whereas ET-3 has a lower affinity for ET_A. ET-1 is the most potent vasoconstrictor in the human cardiovascular system and has remarkably long-lasting actions. ET-1 contributes to vasoconstriction, vascular and cardiac hypertrophy, inflammation, and to the development and progression of cardiovascular disease. Endothelin receptor antagonists have revolutionized the treatment of pulmonary arterial hypertension. Clinical trials continue to explore new applications of endothelin receptor antagonists, particularly in treatment-resistant hypertension, chronic kidney disease and patients receiving antiangiogenic therapies. Translational studies have identified important roles for the endothelin isoforms and new therapeutic targets during development, in fluid-electrolyte homeostasis, and in cardiovascular and neuronal function. Novel pharmacological strategies are emerging in the form of small-molecule epigenetic modulators, biologics (such as monoclonal antibodies for ET_B) and possibly signalling pathway-biased agonists and antagonists.

Transfer and Vascular Effect of Endothelin Receptor Antagonists in the Human Placenta

Increasing evidence suggests a role for the ET (endothelin) system in preeclampsia. Hence, blocking this system with endothelin receptor antagonists (ERAs) could be a therapeutic strategy. Yet, clinical studies are lacking due to possible teratogenic effects of ERAs. In this study, we investigated the placental transfer of ERAs and their effect on ET-1-mediated vasoconstriction. Term placentas were dually perfused with the selective ET_AR (ET type A receptor) antagonists sitaxentan and ambrisentan or the nonselective ET_AR/ET_BR antagonist macitentan and subsequently exposed to ET-1 in the fetal circulation. ET-1 concentration-response curves after incubation with sitaxentan, ambrisentan, macitentan, or the selective ET_BR antagonist BQ-788 were also constructed in isolated chorionic plate arteries using wire-myography, and gene expression of the ET-system was quantified in healthy and early onset preeclamptic placentas. At steady state, the mean fetal-to-maternal transfer ratios were 0.32±0.05 for sitaxentan, 0.21±0.02 for ambrisentan, and 0.05±0.01 for macitentan. Except for BQ-788, all ERAs lowered the response to ET-1, both in the perfused cotyledon and isolated chorionic plate arteries. Placental gene expression of ECE-1, ET_AR, and ET_BR were comparable in healthy and preeclamptic placentas, while ET-1 expression was higher in preeclampsia. Our study is the first to show direct transfer of ERAs across the term human placenta. Furthermore, ET_AR exclusively mediates ET-1-induced constriction in the fetoplacental vasculature. Given its limited transfer, macitentan could be considered as potential preeclampsia therapy. Extending knowledge on placental transfer to placentas of preeclamptic pregnancies is required to determine whether ERAs might be applied safely in preeclampsia.

Endothelin: 30 Years From Discovery to Therapy

Discovered in 1987 as a potent endothelial cell-derived vasoconstrictor peptide, endothelin-1 (ET-1), the predominant member of the endothelin peptide family, is now recognized as a multifunctional peptide with cytokine-like activity contributing to almost all aspects of physiology and cell function. More than 30 000 scientific articles on endothelin were published over the past 3 decades, leading to the development and subsequent regulatory approval of a new class of therapeutics-the endothelin receptor antagonists (ERAs). This article reviews the history of the discovery of endothelin and its role in genetics, physiology, and disease. Here, we summarize the main clinical trials using ERAs and discuss the role of endothelin in cardiovascular diseases such as arterial hypertension, preecclampsia, coronary atherosclerosis, myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) caused by spontaneous coronary artery dissection (SCAD), Takotsubo syndrome, and heart failure. We also discuss how endothelins contributes to diabetic kidney disease and focal segmental glomerulosclerosis, pulmonary arterial hypertension, as well as cancer, immune disorders, and allograft rejection (which all involve ET_A autoantibodies), and neurological diseases. The application of ERAs, dual endothelin receptor/angiotensin receptor antagonists (DARAs), selective ET_B agonists, novel biologics such as receptor-targeting antibodies, or immunization against ET_A receptors holds the potential to slow the progression or even reverse chronic noncommunicable diseases. Future clinical studies will show whether targeting endothelin receptors can prevent or reduce disability from disease and improve clinical outcome, quality of life, and survival in patients.

Effects of ECE-1b rs213045 and rs2038089 polymorphisms on the development of contrast-induced acute kidney injury in patients with acute coronary syndrome

OBJECTIVE

Endothelin-1 (ET-1) promotes the progression and induction of sclerotic renal changes in end-stage kidney disease. Membrane-bound endothelin-converting enzyme 1 (ECE-1) is involved in the production of ET-1. The aim of this study was to assess the effects of ECE-1b rs213045 and rs2038089 polymorphisms, which have been shown to be involved in the development of atherosclerosis, hypertension, and nephropathy, on the development of contrast-induced acute kidney injury (CI-AKI) in patients with acute coronary syndrome.

METHODS

Our study included 38 patients with CI-AKI (CI-AKI[+]) and 55 patients without CI-AKI (CI-AKI[-]) who had coronary syndrome. The ECE-1b polymorphisms rs213045 and rs2038089 were assessed using real-time PCR. Serum ET-1 levels were measured by ELISA.

RESULTS

The distributions of ECE-1b rs213045 and rs2038089 polymorphisms were similar between the two groups. Additionally, the serum ET-1 level did not different between the groups and was not associated with the ECE-1b polymorphisms. Peri-procedural low systolic blood pressure (SBP) was identified as a risk factor for CI-AKI development.

CONCLUSION

Our findings indicate that ECE-1b rs213045 and rs2038089 polymorphisms are not associated with CI-AKI development and that peri-procedural low SBP is a risk factor for CI-AKI. However, variations in ECE-1b rs2038089 may contribute to the development of CI-AKI.

Renin-Angiotensin-Aldosterone System Modulates Blood Pressure Response During Vascular Endothelial Growth Factor Receptor Inhibition

Objectives

This study postulated that antihypertensive therapy with renin-angiotensin-aldosterone system (RAAS) inhibition may mitigate vascular endothelial growth factor inhibitor (VEGFi)–mediated increases in blood pressure more effectively than other antihypertensive medications in patients receiving VEGFi therapy.

Background

VEGFi therapy is commonly used in the treatment of cancer. One common side effect of VEGFi therapy is elevated blood pressure. Evidence suggests that the RAAS may be involved in VEGFi-mediated increases in blood pressure.

Methods

This retrospective cohort analysis was performed using a de-identified version of the electronic health record at Vanderbilt University Medical Center in Nashville, Tennessee. Subjects with cancer who were exposed to VEGFi therapy were identified, and blood pressure and medication data were extracted. Changes in mean systolic and diastolic blood pressure in response to VEGFi therapy in patients receiving RAAS inhibitor (RAASi) therapy before VEGFi initiation were compared with changes in mean systolic and diastolic blood pressure in patients not receiving RAASi therapy before VEGFi initiation.

Results

Mean systolic and diastolic blood pressure rose in both groups after VEGFi use; however, patients who had RAASi therapy before VEGFi initiation had a significantly lower increase in systolic blood pressure as compared with patients with no RAASi therapy (2.46 mm Hg [95% confidence interval: 0.7 to 4.2] compared with 4.56 mm Hg [95% confidence interval: 3.5 to 5.6], respectively; p = 0.034).

Conclusions

In a real-world clinical population, RAASi therapy before VEGFi initiation may ameliorate VEGFi-mediated increases in blood pressure. Randomized clinical trials are needed to further our understanding of the role of RAASi therapy in VEGFi-mediated increases in blood pressure.

Preeclampsia: Maternal Systemic Vascular Disorder Caused by Generalized Endothelial Dysfunction Due to Placental Antiangiogenic Factors

Preeclampsia, a systemic vascular disorder characterized by new-onset hypertension and proteinuria after 20 weeks of gestation, is the leading cause of maternal and perinatal morbidity and mortality. Maternal endothelial dysfunction caused by placental factors has long been accepted with respect to the pathophysiology of preeclampsia. Over the past decade, increased production of placental antiangiogenic factors has been identified as a placental factor leading to maternal endothelial dysfunction and systemic vascular dysfunction. This review summarizes the recent advances in understanding the molecular mechanisms of endothelial dysfunction caused by placental antiangiogenic factors, and the novel clinical strategies based on these discoveries.

Endothelin receptor antagonism during preeclampsia: a matter of timing?

Preeclampsia (PE) is a pregnancy complication, featuring elevated blood pressure and proteinuria, with no appropriate treatment. Activation of the endothelin system has emerged as an important pathway in PE pathophysiology based on experimental PE models where endothelin receptor antagonists (ERAs) prevented or attenuated hypertension and proteinuria. Hence, ERAs have been suggested as potential therapy for PE. However, developmental toxicity studies in animals have shown severe teratogenic effects of ERAs, particularly craniofacial malformations. Nonetheless, sporadic cases of pregnancy in women using ERAs to treat pulmonary hypertension have been described. In this review we give an overview of cases describing ERA use in pregnancy and critically address their possible teratogenic effects. A systematic search in literature yielded 18 articles describing 39 cases with ERA exposure during human pregnancy. In most cases there was only exposure in the first trimester, but exposure later or throughout pregnancy was reported in five cases. Elective termination of pregnancy was performed in 12 pregnancies (31%), two ended in a spontaneous miscarriage (5%) and no fetal congenital abnormalities have been described in the remaining cases. These preliminary findings support the idea that ERA treatment for severe, early onset PE might be an option if applied later in pregnancy, when organogenesis is completed to avoid teratogenic risks. However, third trimester toxicology studies are warranted to evaluate drug safety. Subsequently, it remains to be established whether ERA treatment is effective for alleviating maternal symptoms, as demonstrated in preclinical PE models, allowing pregnancy prolongation without leading to adverse neonatal outcomes.

Expert recommendations on the management of hypertension in patients with ovarian and cervical cancer receiving bevacizumab in the UK

Bevacizumab is an anti-vascular endothelial growth factor monoclonal antibody that may prolong survival in ovarian and cervical cancer when given in combination with chemotherapy. It works by blocking the signalling pathways that are required for tumour angiogenesis, potentially limiting the cancer’s ability to grow and spread. Hypertension is a known side effect of all angiogenesis inhibitors and could lead to interruption or premature discontinuation of effective anti-cancer treatment. Hypertension may also act as a barrier to the initiation of such treatment. In this review, we aim to present clear and practical recommendations on the management of blood pressure in ovarian and cervical cancer patients before, during and after bevacizumab treatment. This guidance covers considerations before initiating bevacizumab therapy and recommendations on the management of patients who develop hypertension, or who experience worsening of pre-existing hypertension, during bevacizumab treatment, and once the course of bevacizumab has been completed. These recommendations were developed collaboratively by a group of clinicians, comprising cardiologists, oncologists, a general practitioner and specialist oncology nurses, with expertise and practical experience in either oncology or hypertension. The aim of these recommendations is to support oncologists with hypertension assessment and management to facilitate starting or continuing bevacizumab.

Microparticles from vascular endothelial growth factor pathway inhibitor-treated cancer patients mediate endothelial cell injury

Vascular endothelial growth factor pathway inhibitors (VEGFi), used as anti-angiogenic drugs to treat cancer are associated with cardiovascular toxicities through unknown molecular mechanisms. Endothelial cell-derived microparticles (ECMPs) are biomarkers of endothelial injury and are also functionally active since they influence downstream target cell signalling and function. We questioned whether microparticle (MP) status is altered in cancer patients treated with VEGFi and whether they influence endothelial cell function associated with vascular dysfunction. Plasma MPs were isolated from cancer patients before and after treatment with VEGFi (pazopanib, sunitinib, or sorafenib). Human aortic endothelial cells (HAECs) were stimulated with isolated MPs (106 MPs/mL). Microparticle characterization was assessed by flow cytometry. Patients treated with VEGFi had significantly increased levels of plasma ECMP. Endothelial cells exposed to post-VEGFi treatment ECMPs induced an increase in pre-pro-ET-1 mRNA expression, corroborating the increase in endothelin-1 (ET-1) production in HAEC stimulated with vatalanib (VEGFi). Post-VEGFi treatment MPs increased generation of reactive oxygen species in HAEC, effects attenuated by ETA (BQ123) and ETB (BQ788) receptor blockers. VEGFi post-treatment MPs also increased phosphorylation of the inhibitory site of endothelial nitric oxide synthase (eNOS), decreased nitric oxide (NO), and increased ONOO- levels in HAEC, responses inhibited by ETB receptor blockade. Additionally, gene expression of proinflammatory mediators was increased in HAEC exposed to post-treatment MPs, effects inhibited by BQ123 and BQ788. Our findings define novel molecular mechanism involving interplay between microparticles, the ET-1 system and endothelial cell pro-inflammatory and redox signalling, which may be important in cardiovascular toxicity and hypertension associated with VEGFi anti-cancer treatment. New and noteworthy: our novel data identify MPs as biomarkers of VEGFi-induced endothelial injury and important mediators of ET-1-sensitive redox-regulated pro-inflammatory signalling in effector endothelial cells, processes that may contribute to cardiovascular toxicity in VEGFi-treated cancer patients.

Risk factors for hypertensive retinopathy in a Chinese population with hypertension: The Beijing Eye study

Hypertensive retinopathy (HRP) is a clinical feature and systemic manifestation of hypertension. There have been few reports on the risk factors for hypertensive retinopathy in China. The aim of the present study was to describe risk factors associated with HRP in a population-based sample of Chinese patients with hypertension in Beijing. The clinical data of 228 hypertensive patients was retrospectively studied, including 112 patients with retinopathy for the HRP group and 116 patients without retinopathy for the NO-HRP group. Basic clinical data and plasma clinical indicators of the two groups were compared. Logistic regression models were used to assess risk factors associated with HRP. Duration of hypertension, smoking habits, family history of hypertension, plasma level of endothelin-1 (ET-1) and systolic and diastolic blood pressure were significantly increased in the HRP group compared with the NO-HRP group (P<0.05). No significant differences were identified between the two groups for other factors. Logistic regression models indicated that hypertension duration (P<0.001, 95% CI: 0.962-0.988) and ET-1 level (P<0.001, 95% CI: 1.144-1.278) were significantly associated with HRP. The diagnostic threshold of ET-1 to diagnosis HRP was 43.5 ng/l. Of the factors studied, longer hypertension duration and elevated ET-1 level were identified to be risk factors for HRP in patients with hypertension from Beijing. Detecting the plasma level of ET-1 in patients with hypertension may be a useful diagnostic indicator for HRP.

Cumulative dose of bevacizumab associates with albuminuria rather than podocyturia in cancer patients

Angiogenesis inhibition with bevacizumab, a monoclonal antibody against vascular endothelial growth factor A (VEGF-A), is an anticancer treatment associated with hypertension and renal glomerular toxicity referred to as a preeclampsia-like syndrome. In preeclampsia, podocyturia predates proteinuria and clinical features of preeclampsia, and is regarded as a biomarker of ongoing glomerular injury. Using a quantitative polymerase chain reaction of the podocyte-specific molecules nephrin, podocin, and VEGF-A in the urine, we examined whether podocyturia is present in bevacizumab-treated cancer patients, and whether it relates to proteinuria and the cumulative dose of bevacizumab. Urine samples were cross-sectionally collected from 43 bevacizumab-treated patients, 21 chemotherapy-treated patients, and 7 healthy controls. Urinary protein-to-creatinine ratio (mean and range) was 32.0 mg/mmol (5.2-284.4) in the bevacizumab group, compared with 11.4 mg/mmol (1.1-21.0) in the chemotherapy group and 7.4 mg/mmol (3.9-16.5) (P < .05) in healthy controls, whereas urinary albumin-to-creatinine ratio values in the three groups were, respectively, 18.9 mg/mmol (0.1-227.7), 1.5 mg/mmol (0.2-3.5), and 0.2 mg/mmol (0.1-0.4) (P < .05). The cumulative dose of bevacizumab ranged from 550 to 93,628 mg. Urinary podocin mRNA expression was undetectable in 59% of participants, urinary nephrin mRNA expression per mmol creatinine ranged from 0.0 to 5.3 and urinary VEGF-A mRNA expression from 0.0 to 2.7. Urinary nephrin mRNA expression did not correlate to the albumin-to-creatinine ratio or the cumulative dose of bevacizumab, whereas the latter correlated with the albumin-to-creatinine ratio (r = 0.77; P < .001). Our results demonstrate that the cumulative dose of bevacizumab is closely correlated with albuminuria but not with podocyturia as measured with the quantitative polymerase chain reaction technique, challenging the feasibility of this measurement to monitor ongoing glomerular injury in patients chronically treated with bevacizumab.

Management of VEGF-Targeted Therapy-Induced Hypertension

PURPOSE OF REVIEW

From a physiological point of view, VEGFs (vascular endothelial growth factors) and their receptors (VEGFR) play a critical role in vascular development angiogenesis, endothelial function, and vascular tone. On the pathological side, VEGF-VEGFR signaling may induce dysregulated angiogenesis, which contributes to the growth and to the spread of tumors, being essential for neoplastic proliferation and invasion.

RECENT FINDINGS

Pharmacological inhibition of VEGF-VEGFR is now a cornerstone in the treatment of many malignancies; however, treatment with VEGF inhibitors is commonly associated with an increase in blood pressure values. This side effect is strictly connected with the mechanism of action of these medications and might represent an index of therapy efficacy. The optimal management of this form of hypertension is, at present, not clear. Calcium channel blockers and renin-angiotensin system inhibitors probably represent the most appropriate classes of hypertensive dugs for the treatment of this condition; however, no conclusive data are presently available.

Bevacizumab-induced hypertension: Clinical presentation and molecular understanding

Bevacizumab is a vascular endothelial growth factor-A-specific angiogenesis inhibitor indicated as an adjunct to chemotherapy for the treatment of several types of cancer. Hypertension is commonly observed during bevacizumab treatment, and high-grade toxicity can limit therapy and lead to other cardiovascular complications. The factors that contribute to interindividual variability in blood pressure response to bevacizumab treatment are not well understood. In this review, we outline research efforts to understand the mechanisms and pathophysiology of hypertension resulting from bevacizumab treatment. Moreover, we highlight current knowledge of the pharmacogenetics of bevacizumab-induced hypertension, which may be used to develop strategies to prevent or minimize this toxicity.

Cardiac Metabolic Deregulation Induced by the Tyrosine Kinase Receptor Inhibitor Sunitinib is rescued by Endothelin Receptor Antagonism

The growing field of cardio-oncology addresses the side effects of cancer treatment on the cardiovascular system. Here, we explored the cardiotoxicity of the antiangiogenic therapy, sunitinib, in the mouse heart from a diagnostic and therapeutic perspective. We showed that sunitinib induces an anaerobic switch of cellular metabolism within the myocardium which is associated with the development of myocardial fibrosis and reduced left ventricular ejection fraction as demonstrated by echocardiography. The capacity of positron emission tomography with [18F]fluorodeoxyglucose to detect the changes in cardiac metabolism caused by sunitinib was dependent on fasting status and duration of treatment. Pan proteomic analysis in the myocardium showed that sunitinib induced (i) an early metabolic switch with enhanced glycolysis and reduced oxidative phosphorylation, and (ii) a metabolic failure to use glucose as energy substrate, similar to the insulin resistance found in type 2 diabetes. Co-administration of the endothelin receptor antagonist, macitentan, to sunitinib-treated animals prevented both metabolic defects, restored glucose uptake and cardiac function, and prevented myocardial fibrosis. These results support the endothelin system in mediating the cardiotoxic effects of sunitinib and endothelin receptor antagonism as a potential therapeutic approach to prevent cardiotoxicity. Furthermore, metabolic and functional imaging can monitor the cardiotoxic effects and the benefits of endothelin antagonism in a theranostic approach.

Endothelin receptor-specific control of endoplasmic reticulum stress and apoptosis in the kidney

Endothelin-1 (ET-1) promotes renal damage during cardiovascular disease; yet, the molecular mechanisms involved remain unknown. Endoplasmic reticulum (ER) stress, triggered by unfolded protein accumulation in the ER, contributes to apoptosis and organ injury. These studies aimed to determine whether the ET-1 system promotes renal ER stress development in response to tunicamycin. ET_B deficient (ET_B def) or transgenic control (TG-con) rats were used in the presence or absence of ET_A receptor antagonism. Tunicamycin treatment similarly increased cortical ER stress markers in both rat genotypes; however, only ET_B def rats showed a 14-24 fold increase from baseline for medullary GRP78, sXBP-1, and CHOP. Pre-treatment of TG-con rats with the ET_A blocker ABT-627 for 1 week prior to tunicamycin injection significantly reduced the ER stress response in cortex and medulla, and also inhibited renal apoptosis. Pre-treatment with ABT-627 failed to decrease renal ER stress and apoptosis in ET_B def rats. In conclusion, the ET-1 system is important for the development of tunicamycin-induced renal ER stress and apoptosis. ET_A receptor activation induces renal ER stress genes and apoptosis, while functional activation of the ET_B receptor has protective effects. These results highlight targeting the ET_A receptor as a therapeutic approach against ER stress-induced kidney injury.

The Potential Role of Nitric Oxide in Halting Cancer Progression Through Chemoprevention

Nitric oxide (NO) in general plays a beneficial physiological role as a vasorelaxant and the role of NO is decided by its concentration present in physiological environments. NO either facilitates cancer-promoting characters or act as an anti-cancer agent. The dilemma in this regard still remains unanswered. This review summarizes the recent information on NO and its role in carcinogenesis and tumor progression, as well as dietary chemopreventive agents which have NO-modulating properties with safe cytotoxic profile. Understanding the molecular mechanisms and cross-talk modulating NO effect by these chemopreventive agents can allow us to develop better therapeutic strategies for cancer treatment.

Endothelin-1 and antiangiogenesis

Antiangiogenesis, targeting vascular endothelial growth factor (VEGF), has become a well-established treatment for patients with cancer. This treatment is associated with nitric oxide (NO) suppression and a dose-dependent activation of the endothelin system, resulting in preeclampsia-like features, particularly hypertension and renal injury. Studies in endothelium NO synthase (eNOS)-deficient mice and pharmacological treatment with endothelin receptor blockers and sildenafil indicate that an activated endothelin system, rather than NO suppression, mediates the side effects of angiogenesis inhibitors. Activation of the endothelin system is also observed in preeclamptic women, where it is related to the increased placental production of sFlt-1, the soluble form of the VEGF receptor-1. This receptor binds VEGF, thereby having the same consequences as antiangiogenic treatment with VEGF inhibitors. The side effects of antiangiogenic treatment in patients with cancer may be dose limiting, thereby impairing its therapeutic potential. In addition, because endothelin exerts proangiogenic effects, investigation of the effects of endothelin receptor blockade in patients with cancer treated with angiogenesis inhibitors is warranted.

The emerging role of endothelin-1 in the pathogenesis of pre-eclampsia

Pre-eclampsia (PE) is the most frequently encountered medical complication during pregnancy. It is characterized by a rise in systemic vascular resistance with a relatively low cardiac output and hypovolemia, combined with severe proteinuria. Despite the hypovolemia, renin-angiotensin system (RAS) activity is suppressed and aldosterone levels are decreased to the same degree as renin. This suggests that the RAS is not the cause of the hypertension in PE, but rather that its suppression is the consequence of the rise in blood pressure. Abnormal placentation early in pregnancy is widely assumed to be an important initial event in the onset of PE. Eventually, this results in the release of anti-angiogenic factors [in particular, soluble Fms-like tyrosine kinase-1 (sFlt-1)] and cytokines, leading to generalized vascular dysfunction. Elevated sFlt-1 levels bind and inactivate vascular endothelial growth factor (VEGF). Of interest, VEGF inhibition with drugs like sunitinib, applied in cancer patients, results in a PE-like syndrome, characterized by hypertension, proteinuria and renal toxicity. Both in cancer patients treated with sunitinib and in pregnant women with PE, significant rises in endothelin-1 occur. Multiple regression analysis revealed that endothelin-1 is an independent determinant of the hypertension and proteinuria in PE, and additionally a renin suppressor. Moreover, studies in animal models representative of PE, have shown that endothelin receptor blockers prevent the development of this disease. Similarly, endothelin receptor blockers are protective during sunitinib treatment. Taken together, activation of the endothelin system emerges as an important pathway causing the clinical manifestations of PE. This paper critically addresses this concept, taking into consideration both clinical and preclinical data, and simultaneously discusses the therapeutic consequences of this observation.

Effect of high salt diet on blood pressure and renal damage during vascular endothelial growth factor inhibition with sunitinib

BACKGROUND

Antiangiogenic treatment with the multitargeted vascular endothelial growth factor (VEGF) receptor inhibitor sunitinib associates with a blood pressure (BP) rise and glomerular renal injury. Recent evidence indicates that VEGF derived from tubular cells is required for maintenance of the peritubular vasculature. In the present study, we focussed on tubular and glomerular pathology induced by sunitinib and explored whether a high salt (HS) diet augments the BP rise and renal abnormalities.

METHODS

Normotensive Wistar Kyoto (WKY) rats were exposed to a normal salt (NS) or HS diet for 2 weeks and subsequently for 8 days to sunitinib or vehicle administration after which the rats were euthanized and kidneys excised. Mean arterial pressure (MAP) was telemetrically measured. Urine was sampled for proteinuria and endothelinuria, and blood for measurement of endothelin-1, creatinine and cystatin C.

RESULTS

Compared with the NS diet, MAP rapidly rose by 27 ± 3 mmHg with the HS diet. On sunitinib, MAP rose further by 15 ± 1 with the NS and by 23 ± 4 mmHg with the HS diet (P < 0.05). The HS diet itself had no effect on proteinuria, endothelinuria or the plasma levels of endothelin-1, creatinine and cystatin C. Only with the HS diet, sunitinib administration massively increased proteinuria and endothelinuria and these two parameters were related (r = 0.50, P < 0.01). Likewise, renal glomerular pathology was enhanced during sunitinib with the HS diet, whereas tubulointerstitial injury or reduced peritubular capillary density did not occur.

CONCLUSIONS

An HS diet induces a marked BP rise in WKY rats and exacerbates both the magnitude of the BP rise and glomerular injury induced by sunitinib.

Population pharmacokinetic-pharmacodynamic modelling of 24-h diastolic ambulatory blood pressure changes mediated by axitinib in patients with metastatic renal cell carcinoma

BACKGROUND

Increased blood pressure (BP) is commonly observed in patients treated with vascular endothelial growth factor pathway inhibitors, including axitinib. Ambulatory BP monitoring (ABPM) and pharmacokinetic data were collected in a randomised, double-blind phase II study of axitinib with or without dose titration in previously untreated patients with metastatic renal cell carcinoma.

OBJECTIVE

Aims of these analyses were to (1) develop a population pharmacokinetic-pharmacodynamic model for describing the relationship between axitinib exposure and changes in diastolic BP (dBP) and (2) simulate changes in dBP with different axitinib dosing regimens.

METHODS

We employed a three-stage modelling approach, which included development of (1) a baseline 24-h ABPM model, (2) a pharmacokinetic model from serial and sparse pharmacokinetic data, and (3) an indirect-response, maximum-effect (Emax) model to evaluate the exposure-driven effect of axitinib on dBP. Simulations (N = 1,000) were performed using the final pharmacokinetic-pharmacodynamic model to evaluate dBP changes on days 4 and 15 of treatment with different axitinib doses.

RESULTS

Baseline ABPM data from 62 patients were best described by 24-h mean dBP and two cosine terms. The final indirect-response Emax model showed good agreement between observed 24-h ABPM data and population and individual predictions. The maximum increase in dBP was 20.8 %, and the axitinib concentration at which 50 % of the maximal increase in dBP was reached was 12.4 ng/mL.

CONCLUSION

Our model adequately describes the relationship between axitinib exposure and dBP increases. Results from these analyses may potentially be applied to infer dBP changes in patients administered axitinib at nonstandard doses.

Are predictions of cancer response to targeted drugs, based on effects in unrelated tissues, the ‘Black Swan’ events?

Adverse effects of targeted drugs on normal tissues can predict the cancer response. Rash correlates with efficacy of erlotinib, cetuximab and gefitinib and onset of arterial hypertension with response to bevacizumab, sunitinib, axitinib and sorafenib, possible examples of ‘Black Swan’ events, unexpected scientific observations, as described by Karl Popper in 1935. The proposition is that our patients have individual intrinsic variants of cell growth control, important for tumor response and adverse effects on tumor-unrelated tissue. This means that the lack of predictive side effects in healthy tissue is linked with poor results of tumor therapy when tumor resistance is caused by mechanisms that protect all cells of that patient from the targeted drug effects.

Greater Sensitivity of Blood Pressure Than Renal Toxicity to Tyrosine Kinase Receptor Inhibition With Sunitinib

Hypertension and renal injury are off-target effects of sunitinib, a tyrosine kinase receptor inhibitor used for the treatment of various tumor types. Importantly, these untoward effects are accompanied by activation of the endothelin system. Here, we set up a study to explore the dose dependency of these side effects. Normotensive Wistar Kyoto rats were exposed to 3 different doses of sunitinib or vehicle. After 8 days, rats were euthanized. Telemetrically measured blood pressure rose dose dependently, from 13 to 30 mm Hg. Proteinuria was present at all doses, but a rise in cystatin C occurred only at the intermediate and high doses. Compared with vehicle circulating endothelin-1 increased dose dependently, whereas 24-hour urinary endothelin excretion decreased. Light and electron microscopy revealed glomerular endotheliosis and ischemia with the intermediate and high doses of sunitinib but completely absent histological abnormalities with the low dose. Podocyte number per glomerular circumference did not change. Glomerular nephrin, Neph1, podocin, and endothelin-converting enzyme gene expression were downregulated in a dose-dependent manner. We conclude that the sunitinib-induced rise in blood pressure requires lower doses than its induction of renal function impairment and that functional changes in glomerular filtration barrier contribute to the occurrence of proteinuria, given the lack of histopathologic changes with the low dose of sunitinib.

Endothelium-derived ET-1 and the development of renal injury

The role of the vasoactive peptide endothelin-1 (ET-1) in renal injury is not fully understood. In this review, we examine the genetic models available to understand the autocrine/paracrine mechanisms by which ET-1 leads to renal injury and propose the working hypothesis that endothelium-derived ET-1 induces renal injury by initiating renal tubular apoptosis in a paracrine manner.

Plasma lactate and incident hypertension in the atherosclerosis risk in communities study

BACKGROUND

Recent evidence suggests that insufficient oxidative capacity or mitochondrial dysfunction may play a causal role in the development of high blood pressure. However, this hypothesis has not been tested in the general population. We hypothesized that lactate, a measure of oxidative capacity, would be positively associated with incident hypertension even after accounting for traditional hypertension risk factors.

METHODS

Plasma lactate was measured in 5,554 participants from the Atherosclerosis Risk in Communities (ARIC) Study with no subclinical or diagnosed hypertension at baseline (1996-1998). Incident hypertension was defined by self-report or hypertension medication use. Analyses were performed with Cox proportional hazards models.

RESULTS

The mean age was 61.9 years, and the mean lactate was 0.8 mmol/L. During a median follow-up period of 11.9 years (range = 26.9 days to 13.4 years), there were 3,849 new cases of hypertension. The fourth quartile of lactate (compared with the first quartile) was associated with an elevated risk of hypertension (hazard ratio (HR) = 1.18; 95% confidence interval (CI) = 1.07-1.31) even after adjustment for traditional risk factors, including baseline systolic and diastolic blood pressure. This association was stronger when the population was restricted to participants with normal blood pressure (<120mm Hg/<80mm Hg; HR = 1.42; 95% CI = 1.23-1.63). In strata of sex, the association was strong in women vs. null in men (P interaction = 0.01).

CONCLUSIONS

Plasma lactate is associated with incident hypertension in women, especially with a normal blood pressure (<120mm Hg/<80mm Hg). Future studies should elucidate the mechanisms underlying these observations.

The contribution of VEGF signalling to fostamatinib-induced blood pressure elevation

BACKGROUND AND PURPOSE

Fostamatinib is an inhibitor of spleen tyrosine kinase (TK). In patients, fostamatinib treatment was associated with increased BP. Some TK inhibitors cause BP elevation, by inhibiting the VEGF receptor 2 (VEGFR2). Here, we have assessed the mechanistic link between fostamatinib-induced BP elevation and inhibition of VEGF signalling.

EXPERIMENTAL APPROACH

We used conscious rats with automated blood sampling and radio telemetry and anaesthetized rats to measure cardiovascular changes. Rat isolated aorta and isolated hearts, and human resistance vessels in vitro were also used. NO production by human microvascular endothelial cells was measured with the NO-dependent probe, DAF-FM and VEGFR2 phosphorylation was determined in mouse lung, ex vivo.

KEY RESULTS

In conscious rats, fostamatinib dose-dependently increased BP. The time course of the BP effect correlated closely with the plasma concentrations of R406 (the active metabolite of fostamatinib). In anaesthetized rats, infusion of R406 increased BP and decreased femoral arterial conductance. Endothelial function was unaffected, as infusion of R406 did not inhibit hyperaemia- or ACh-induced vasodilatation in rats. R406 did not affect contraction of isolated blood vessels. R406 inhibited VEGF-stimulated NO production from human endothelial cells in vitro, and treatment with R406 inhibited VEGFR2 phosphorylation in vivo. R406 inhibited VEGF-induced hypotension in anaesthetized rats.

CONCLUSIONS AND IMPLICATIONS

Increased vascular resistance, secondary to reduced VEGF-induced NO release from endothelium, may contribute to BP increases observed with fostamatanib. This is consistent with the elevated BP induced by other drugs inhibiting VEGF signalling, although the contribution of other mechanisms cannot be excluded.

Treatment of hypertension and renal injury induced by the angiogenesis inhibitor sunitinib: preclinical study

Common adverse effects of angiogenesis inhibition are hypertension and renal injury. To determine the most optimal way to prevent these adverse effects and to explore their interdependency, the following drugs were investigated in unrestrained Wistar Kyoto rats exposed to the angiogenesis inhibitor sunitinib: the dual endothelin receptor antagonist macitentan; the calcium channel blocker amlodipine; the angiotensin-converting enzyme inhibitor captopril; and the phosphodiesterase type 5 inhibitor sildenafil. Mean arterial pressure was monitored telemetrically. After 8 days, rats were euthanized and blood samples and kidneys were collected. In addition, 24-hour urine samples were collected. After sunitinib start, mean arterial pressure increased rapidly by ≈30 mm Hg. Coadministration of macitentan or amlodipine largely prevented this rise, whereas captopril or sildenafil did not. Macitentan, captopril, and sildenafil diminished the sunitinib-induced proteinuria and endothelinuria and glomerular intraepithelial protein deposition, whereas amlodipine did not. Changes in proteinuria and endothelinuria were unrelated. We conclude that in our experimental model, dual endothelin receptor antagonism and calcium channel blockade are suitable to prevent angiogenesis inhibition-induced hypertension, whereas dual endothelin receptor antagonism, angiotensin-converting enzyme inhibitor, and phosphodiesterase type 5 inhibition can prevent angiogenesis inhibition-induced proteinuria. Moreover, the variable response of hypertension and renal injury to different antihypertensive agents suggests that these side effects are, at least in part, unrelated.

SFlt-1 elevates blood pressure by augmenting endothelin-1-mediated vasoconstriction in mice

Objective

Scavenging of vascular endothelial growth factor (VEGF) elevates blood pressure (BP) in patients receiving anti-angiogenic therapy. Similarly, inhibition of circulation VEGF by its soluble receptor fms-like tyrosine kinase-1 (sFlt-1) underlies BP elevation in pre-eclampsia. Both phenotypes are characterized by augmented production of endothelin-1 (ET-1), suggesting a role for ET-1 in anti-angiogenic hypertension. We aimed to assess the effect of VEGF inhibition on ET-1-induced contractility and downstream ET-1 signaling.

Approach and Results

Male C57BL/6N mice were treated with either sFlt-1 or vehicle and BP was assessed via tail-cuff. Mean arterial pressure of sFlt-1-treated mice markedly increased compared to vehicle-treated controls (N = 11–12, p<0.05). After sacrifice, carotid and mesenteric arteries were isolated for isometric tension measurements. ET-1-induced contractions were similar in mesenteric arteries of vehicle and sFlt-1-treated mice, but augmented in carotid segments of sFlt-1-treated mice compared to controls (N = 9–10, p<0.05). The increased contraction in carotid segments could be completely abrogated by the cyclooxygenase (COX) inhibitor indomethacin (N = 9–10, p<0.05), indicating heightened prostaglandin-mediated vasoconstriction. This was associated with a shift towards procontractile ET_B signaling in sFlt-1-treated mice, possibly explaining the increased ET-1-induced prostaglandin-mediated vasoconstriction. In line with the ex vivo findings, sFlt-1-induced BP elevation could be prevented in vivo by oral treatment with either a high-dose of the COX inhibitor aspirin (N = 7) or with picotamide (N = 9), a dual thromboxane A₂ synthase inhibitor and receptor antagonist.

Conclusions

VEGF inhibition augments the pressor response to ET-1. The cyclooxygenase-thromboxane signaling route downstream of ET-1 might be a possible target to prevent BP elevation during VEGF inhibition.

Hypertension due to antiangiogenic cancer therapy with vascular endothelial growth factor inhibitors: understanding and managing a new syndrome

Novel antiangiogenic cancer therapies, particularly agents that block vascular endothelial growth factor (VEGF) signalling, have improved outcomes in patients with cancers and are now used as first-line therapies for some tumours. However, with VEGF inhibitors (VEGFIs) are new complications, particularly hypertension. VEGFI-induced hypertension is a dose-dependent phenomenon due to on-target effects rather than off-target effects. Increased blood pressure occurs in almost 100% of patients who take VEGFIs, with a subset who develop severe hypertension. Molecular mechanisms underlying VEGFI-induced hypertension are unclear, but endothelial dysfunction and increased vascular resistance, due to impaired nitric oxide signalling, reduced prostacyclin production, endothelin-1 (ET-1) upregulation, oxidative stress, and rarefaction have been implicated. Treatment of hypertension should be aimed at reducing the risk of short-term morbidity associated with hypertension while maintaining effective dosing of antiangiogenic therapy for optimal cancer treatment. Although specific guidelines are not yet available for the management of VEGFI-induced hypertension, angiotensin-converting enzyme inhibitors and dihydropyridine calcium channel blockers are commonly used. Severe hypertension might require reduction of VEGFI dosing, or in some cases, interruption of treatment. As more potent VEGFIs are developed and as more cancer patients are treated with VEGFIs, the burden of hypertension toxicity will increase. This will be further compounded as the use of antiangiogenic drugs broadens to include older patients and those with pre-existing cardiovascular disease. Here we focus on VEGF as a target for antiangiogenesis and how this affects increased blood pressure. Putative mechanisms underlying VEGFI-induced hypertension are highlighted and therapeutic strategies to manage such hypertension are discussed.

Ziv-aflibercept: A novel angiogenesis inhibitor for the treatment of metastatic colorectal cancer

Purpose

The pharmacology, pharmacokinetics, clinical efficacy, safety, and administration of ziv-aflibercept in combination therapy for metastatic colorectal cancer (mCRC) are reviewed.

Summary

Ziv-aflibercept (Zaltrap, Regeneron Pharmaceuticals and sanofi-aventis) is a novel recombinant fusion protein that targets the angiogenesis signaling pathway of tumor cells by blocking vascular endothelial growth factor (VEGF) receptors that play a key role in tumor growth and metastasis; it is a more potent VEGF blocker than bevacizumab. Ziv-aflibercept is approved by the Food and Drug Administration for use in combination with fluorouracil, irinotecan, and leucovorin (the FOLFIRI regimen) for second-line treatment of patients with mCRC who have disease progression during first-line oxaliplatin-based chemotherapy. A Phase III trial demonstrated that relative to FOLFIRI therapy alone, the use of ziv-aflibercept was associated with significantly improved patient response, overall survival, and progression-free survival in patients with good performance status at baseline, including some who had received prior bevacizumab therapy. The most common grade 3 or 4 adverse effects associated with ziv-aflibercept use in clinical studies were neutropenia, hypertension, and diarrhea; the U.S. product labeling warns of potential hemorrhage and other treatment-related risks.

Conclusion

Current clinical data are insufficient to directly compare ziv-aflibercept and bevacizumab when used with standard combination chemotherapy as first- or second-line regimens for mCRC. The role of ziv-aflibercept is currently limited to the second-line setting in combination with irinotecan-based regimens in mCRC patients who have not received irinotecan previously. The role of ziv-aflibercept in chemotherapy for other tumor types is yet to be determined.

Excess maternal glucocorticoids in response to in utero undernutrition inhibit offspring angiogenesis

To test the hypothesis that inhibition of offspring angiogenesis by maternal undernutrition (MUN) is mediated by maternal glucocorticoids, 3 groups of dams were studied: controls received ad libitum food; MUN dams were food restricted by 50% from day 10 of gestation; and metyrapone (MET) dams were food restricted and treated with 0.5 mg/mL of MET, a glucocorticoid synthesis inhibitor. The MUN reduced birth weights, reduced vascular endothelial growth factor (VEGF) abundance in P1 aortas, reduced VEGF and VEGF-R2 abundances in P1 mesenteric arterioles, reduced arteriolar endothelial nitric oxide synthase abundance, reduced microvessel density in the anterior tibialis, reduced endothelial cell branching in culture, reduced arteriolar immunoreactivity for proliferating cell nuclear antigen (PCNA), increased active caspase 3 in P1 mesenteric arterioles, and decreased matrix metalloproteinase (MMP)-2 and MMP-9 abundances in lysates of P1 aortas. All of these effects were prevented by treatment with metyrapone. Collectively, these findings suggest that reduced angiogenesis in MUN offspring involves direct inhibitory effects of maternal glucorticoid on fetal VEGF and its receptors.

Evaluation of the adverse event profile and pharmacodynamics of toceranib phosphate administered to dogs with solid tumors at doses below the maximum tolerated dose

Background

The receptor kinase inhibitor toceranib phosphate (Palladia) was approved for use in dogs in 2009 using a dose of 3.25 mg/kg administered every other day. Preliminary data suggests that lower doses of toeceranib may be associated with a reduced adverse event profile while maintaining sufficient drug exposure to provide biologic activity. The purpose of this study was to determine the Cmax of toceranib in dogs with solid tumors receiving 2.5-2.75 mg/kg every other day and to document the adverse events associated with this dose rate. Secondary objectives included determination of plasma VEGF concentrations in treated dogs and response to therapy.

Results

Dogs with solid tumors were administered toceranib at an intended target dose ranging from 2.5-2.75 mg/kg every other day and plasma samples were obtained for analysis of toceranib and VEGF plasma concentrations on days 0, 7, 14 and 30 of the study at 6 and 8 hours post drug administration. Additionally, plasma samples were obtained at 0, 1, 2, 6, 8, and 12 hours from dogs on day 30 for confirmation of Cmax. Response to therapy was assessed using standard RECIST criteria and adverse events were characterized using the VCOG-CTCAE. Toceranib administered at doses between 2.4-2.9 mg/kg every other day resulted in an average 6–8 hr plasma concentration ranging from 100–120 ng/ml, well above the 40 ng/ml concentration associated with target inhibition. Plasma VEGF concentrations increased significantly over the 30 day treatment period indicating that VEGFR2 inhibition was likely achieved in the majority of dogs. The lower doses of toceranib used in this study were associated with a substantially reduced adverse event profile compared to the established label dose of 3.25 mg/kg EOD.

Conclusions

Doses of toceranib ranging from 2.4-2.9 mg/kg every other day provide drug exposure considered sufficient for target inhibition while resulting in an adverse event profile substantially reduced from that associated with the label dose of toceranib. This lower dose range of toceranib should be considered for future use in dogs with cancer.