Diethelm Tschöpe

Introduction An increased or disturbed activation and aggregation of platelets plays a major role in the pathophysiology of thrombosis and haemostasis and is related to cardiovascular disease processes. In addition to qualitative disturbances of platelet function, changes in thrombopoiesis or an increased elimination of platelets, (e. g., in autoimmune thrombocytopenia), are also of major clinical relevance. Flow cytometry is increasingly used for the specific characterisation of phenotypic alterations of platelets which are related to cellular activation, haemostatic function and to maturation of precursor cells. These new techniques also allow the study of the in vitro response of platelets to stimuli and the modification thereof under platelet-targeted therapy as well as the characterisation of platelet-specific antibodies. In this protocol, specific flow cytometric techniques for platelet analysis are recommended based on a description of the current state of flow cytometric methodology. These recommendations are an attempt to promote the use of these new techniques which are at present broadly evaluated for diagnostic purposes. Furthermore, the definition of the still open questions primarily related to the technical details of the method should help to promote the multi-center evaluation of procedures with the goal to finally develop standardized operation procedures as the basis of interlaboratory reproducibility when applied to diagnostic testing.

OBJECTIVE This study evaluated the long-term safety and efficacy of dapagliflozin as an adjunct to adjustable insulin in patients with type 1 diabetes and inadequate glycemic control. RESEARCH DESIGN AND METHODS DEPICT-1 (Dapagliflozin Evaluation in Patients With Inadequately Controlled Type 1 Diabetes) was a randomized (1:1:1), double-blind, placebo-controlled phase 3 study of dapagliflozin 5 mg and 10 mg in patients with type 1 diabetes (HbA1c 7.5–10.5% [58–91 mmol/mol]) (NCT02268214). The results of the 52-week study, consisting of the 24-week short-term and 28-week extension period, are reported here. RESULTS Of the 833 patients randomized into the study, 708 (85%) completed the 52-week study. Over 52 weeks, dapagliflozin 5 mg and 10 mg led to clinically significant reductions in HbA1c (difference vs. placebo [95% CI] −0.33% [−0.49, −0.17] [−3.6 mmol/mol (−5.4, −1.9)] and −0.36% [−0.53, −0.20] [−3.9 mmol/mol (−5.8, −2.2)], respectively) and body weight (difference vs. placebo [95% CI] −2.95% [−3.83, −2.06] and −4.54% [−5.40, −3.66], respectively). Serious adverse events were reported in 13.4%, 13.5%, and 11.5% of patients in the dapagliflozin 5 mg, 10 mg, and placebo groups, respectively. Although hypoglycemia events were comparable across treatment groups, more patients in the dapagliflozin groups had events adjudicated as definite diabetic ketoacidosis (DKA; 4.0%, 3.4%, and 1.9% in dapagliflozin 5 mg, 10 mg, and placebo groups, respectively). CONCLUSIONS Over 52 weeks, dapagliflozin led to improvements in glycemic control and weight loss in patients with type 1 diabetes, while increasing the risk of DKA.

OBJECTIVE: To assess the antihypertensive efficacy and safety of the combination of the direct renin inhibitor aliskiren and ramipril in patients with diabetes and hypertension. METHODS: In this double-blind, multicentre trial, 837 patients with diabetes mellitus and hypertension (mean sitting diastolic blood pressure [BP] > 95 and < 110 mmHg) were randomised to once-daily aliskiren (150 mg titrated to 300 mg after four weeks; n=282), ramipril (5 mg titrated to 10 mg; n=278) or the combination (n=277) for eight weeks. Efficacy variables were cuff mean sitting diastolic BP (msDBP) and mean sitting systolic BP (msSBP); 24-hour ambulatory BP, plasma renin activity (PRA) and plasma renin concentration (PRC) were also assessed. RESULTS: At week 8, aliskiren, ramipril and aliskiren/ramipril lowered msDBP (mean+/-SEM) by 11.3+/-0.5, 10.7+/-0.5 and 12.8+/-0.5 mmHg, and msSBP by 14.7+/-0.9, 12.0+/-0.9 and 16.6+/-0.9 mmHg, respectively. Aliskiren/ramipril provided superior msDBP reductions to ramipril (p=0.004) or aliskiren (p=0.043) monotherapy; adding aliskiren to ramipril provided an additional mean BP reduction of 4.6/2.1 mmHg. Aliskiren monotherapy was non-inferior to ramipril for msDBP reduction (p=0.0002) and superior for msSBP reduction (p=0.021). All treatments significantly lowered mean 24-hour ambulatory BP. Aliskiren significantly reduced PRA from baseline as monotherapy (by 66%, p<0.0001) or in combination with ramipril (by 48%, p<0.0001), despite large increases in PRC in all treatment groups. Aliskiren was well tolerated as monotherapy or in combination with ramipril. CONCLUSIONS: Combining aliskiren with ramipril provided a greater reduction in msDBP than either drug alone in patients with diabetes and hypertension.

AIMS: To study the recovery of platelet function after discontinuation of clopidogrel treatment in healthy volunteers. METHODS: Ten healthy volunteers were treated with clopidogrel (75 mg day(-1)) for 7 days. CD62P expression and PAC-1 binding were measured by flow cytometry. RESULTS: Adenosine diphosphate (ADP, 30 microM)-induced platelet responses were almost completely inhibited by clopidogrel. After discontinuation of the drug, platelet function gradually increased and complete recovery was seen 7 days after the last clopidogrel dose. The mean difference (95% CI) for ADP-induced PAC-1 binding (fluorescence intensity) between baseline and 7 days after the last dose was 0.01 (0.61, -0.59). Single cell analysis provides direct evidence for an irreversible mode of action of clopidogrel. CONCLUSIONS: This is the first report to directly demonstrate irreversibility of clopidogrel action in humans.