Varenicline aggravates atherosclerotic plaque formation in nicotine-pretreated ApoE knockout mice due to enhanced oxLDL uptake by macrophages through downregulation of ABCA1 and ABCG1 expression.

Varenicline is a widely used and effective drug for smoking cessation. We previously reported that varenicline aggravates atherosclerosis in apolipoprotein E knockout (ApoE KO) mice. However, it remains unknown whether varenicline affects cardiovascular events in patients with nicotine addiction. Here, we examined the effect of varenicline on atherosclerotic plaque formation in nicotine-pretreated ApoE KO mice and oxidized low-density lipoprotein (oxLDL) uptake in nicotine-treated peritoneal macrophages. Varenicline caused significant progression of plaque formation in the whole aorta and aortic root and further accelerated the increased formation of a macrophage-rich plaque area in the aortic root in nicotine-pretreated ApoE KO mice. Varenicline (10 µM) enhanced oxLDL uptake in peritoneal macrophages. Furthermore, this treatment significantly further lowered the decreased protein levels of ATP-binding cassette (ABC) transporter without affecting the expression of scavenger receptors LOX-1 and CD36 in RAW264.7 cells treated with 100 nM nicotine. Varenicline enhanced nicotine-induced oxLDL uptake in macrophages through decreased expression of cholesterol efflux transporters ABCA1 and ABCG1 and thereby progressed atherosclerotic plaque formation. Taken together, we tentatively conclude that nicotine exposure before and/or during varenicline treatment can aggravate varenicline-increased atherosclerotic plaque formation and progression. Therefore, this enhanced risk requires special consideration when prescribing varenicline to smoker patients.

Varenicline promotes endothelial cell migration by lowering vascular endothelial-cadherin levels via the activated α7 nicotinic acetylcholine receptor-mitogen activated protein kinase axis.

Varenicline is a widely used and effective drug for smoking cessation. Despite its efficacy, varenicline increases the risk of cardiovascular disease. We previously demonstrated that varenicline aggravates atherosclerotic plaque formation in apolipoprotein E knockout mice. However, little is known about its effects in vascular endothelial cells. Therefore, we examined whether varenicline promotes migration of human umbilical vein endothelial cells (HUVECs) using the Boyden chamber assay. Varenicline (100µM) markedly promoted migration of HUVECs and decreased expression of vascular endothelial (VE)-cadherin, an endothelial adhesion molecule. Extracellular signal-regulated kinase (ERK), p38 and c-Jun N-terminal kinase (JNK) signaling were markedly activated by varenicline. Methyllycaconitine (MLA; 100nM), an α7 nicotinic acetylcholine receptor (nAChR) antagonist, but not dihydro-ß-erythroidine hydrobromide (DHßE; 20µM) blocked varenicline-stimulated migration and varenicline-activated ERK, p38 and JNK signaling in HUVECs. MLA (100nM), PD98059 (an ERK inhibitor; 20µM), SB203580 (a p38 inhibitor; 20µM) and SP600125 (a JNK inhibitor; 20µM) also blocked cell migration and varenicline-induced downregulation of VE-cadherin expression in HUVECs. These findings suggest that varenicline promotes HUVEC migration by lowering VE-cadherin expression due to activated ERK/p38/JNK signaling through α7 nAChR. These processes probably contribute to varenicline-aggravated atherosclerotic plaque. Hence, an increased risk of cardiovascular events upon varenicline treatment might occur and must be considered in patients with cardiovascular diseases.

Pregnancy outcomes after maternal varenicline use; analysis of surveillance data collected by the European Network of Teratology Information Services.

Varenicline is a smoking cessation aid for which limited data exist concerning safety during human pregnancy. This multicentre prospective observational comparative cohort study was undertaken using surveillance data collected by the European Network of Teratology Information Services. The study sample consisted of 89 varenicline exposed pregnancies and two matched comparator groups; 267 non-teratogen exposed (NTE) controls and 78 exposed to nicotine replacement therapy or bupropion (NRT/B) for smoking cessation. For all exposed pregnancies, varenicline use only occurred in the first trimester, with a considerable proportion discontinuing use in the very early stages of pregnancy. The major congenital malformation rate (n=2/89, 2.25%) was in keeping with the expected background rate (2-4%), and was not significantly increased for first trimester varenicline-exposed infants in comparison with non-exposed controls (vs. NTE: OR 2.02, 95%CI 0.166 to 17.9, vs. NRT/B: OR 0.874, 95%CI 0.0620 to 12.3). However, the small sample size produced very imprecise risk estimates.

Evaluation of the cardiovascular effects of varenicline in rats.

BACKGROUND: Cardiovascular disease is an important cause of morbidity and mortality among tobacco users. Varenicline is widely used worldwide to help smoking cessation, but some published studies have reported associated cardiovascular events. OBJECTIVE: To determine the cardiovascular toxicity induced by varenicline in rats. MATERIALS AND METHODS: We randomly separated 34 rats into two groups: 1) the control group (given only distilled water orally, n=10) and the varenicline group (given 9 µg/kg/day varenicline on days 1-3, 9 µg/kg twice daily on days 4-7, and 18 µg/kg twice daily on days 8-90 [total 83 days], n=24). Each group was then subdivided equally into acute and chronic subgroups, and all rats in these groups were euthanized with anesthesia overdose on days 45 and 90, respectively. Body and heart weights, hemodynamic (mean oxygen saturation, mean blood pressure, and heart rate, electrocardiographic (PR, QRS, and QT intervals) biochemical (oxidants and antioxidants), and histopathological analyses (including immunostaining) were performed. RESULTS: Acute varenicline exposure resulted in loss of body weight, while chronic varenicline exposure caused heart weight loss and decreased mean blood pressure, induced lipid peroxidation, and reduced antioxidant activity. Both acute and chronic varenicline exposure caused impairment of mean oxygen saturation. QT interval was prolonged in the chronic varenicline group, while PR interval prolongation was statistically significant in both the control and acute varenicline groups. Caspase-9 activity was also significantly increased by chronic exposure. Moreover, histopathological observations revealed severe morphological heart damage in both groups. CONCLUSION: Adverse effects of chronic varenicline exposure on cardiovascular tissue were confirmed by our electrocardiographic, biochemical, and histopathological analyses. This issue needs to be investigated with new experimental and clinical studies to evaluate the exact mechanism(s) of the detrimental effects of varenicline. Physicians should bear in mind the toxic effects of varenicline on the cardiovascular system when prescribing it for smoking cessation.