The goals of this study were to assess the extent of human intestinal drug transporter expression, determine the subcellular localization of the drug uptake transporter OATP1A2, and then to assess the effect of grapefruit juice consumption on OATP1A2 expression relative to cytochrome P450 3A4 and MDR1. Expression of drug uptake and efflux transporters was assessed using human duodenal biopsy samples. Fexofenadine uptake by different transporters was measured in a transporter-transfected cell line. We investigated the influence of grapefruit juice on pharmacokinetics of orally administered fexofenadine. The effect of grapefruit juice on the expression of intestinal transporters was determined using real-time polymerase chain reaction and Western blot analysis. In the duodenum of healthy volunteers, an array of CYP enzymes as well as uptake and efflux transporters was expressed. Importantly, uptake transporters thought to be liver-specific, such as OATP1B1 and 1B3, as well as OATP2B1 and 1A2 were expressed in the intestine. However, among OATP transporters, only OATP1A2 was capable of fexofenadine uptake when assessed in vitro. OATP1A2 colocalized with MDR1 to the brush border domain of enterocytes. Consumption of grapefruit juice concomitantly or 2 h before fexofenadine administration was associated with reduced oral fexofenadine plasma exposure, whereas intestinal expression of either OATP1A2 or MDR1 remained unaffected. In conclusion, an array of drug uptake and efflux transporters are expressed in the human intestine. OATP1A2 is likely the key intestinal uptake transporter for fexofenadine absorption whose inhibition results in the grapefruit juice effect. Although short-term grapefruit juice ingestion was associated with reduced fexofenadine availability, OATP1A2 or MDR1 expression was unaffected.

T h e ne w e ngl a nd jou r na l o f m e dicine n engl j med 372;6 nejm.org february 5, 2015

A growing number of patients, particularly those with advanced, chronic coronary artery disease, experience symptoms of angina that are refractory to treatment with β-blockers, calcium-channel blockers, and long-acting nitrates, despite revascularization. The management of patients with refractory angina who are unsuitable for further revascularization is strikingly different across the world, and is contingent on local resources and available expertise. Mortality in this patient population has decreased, but enhancing quality of life remains a challenge. New treatment principles are emerging in current practice, such as metabolic modulation, therapeutic angiogenesis, and novel interventional techniques (coronary in-flow redistribution and approaches to chronic total occlusion). The contemporary management of refractory angina encourages individualized, patient-centred care in interdisciplinary, specialized clinics. Global initiatives are required to address complex clinical problem-solving for patients with refractory angina. In this Review, we discuss the epidemiology of refractory angina, and provide an update on the pharmacological, noninvasive, and interventional options that are available to these patients or are under development.

Treatment with auto-CD34+ cells resulted in clinically meaningful durable improvements in TET and AF at 3-, 6- and 12-months, as well as a reduction in 24-month mortality in this patient-level meta-analysis.

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In a contemporary population where both RA and FA were used, the safety benefit associated with RA is offset by a paradoxical increase in VASCs among FA patients. The existence of this radial paradox should be taken into consideration, especially among trainees and default radial operators.