ABSTRACT
Pulmonary hypertension (PH) is a common complication of haemolytic anaemia. Intravascular haemolysis leads to nitric oxide (NO) depletion, endothelial and smooth muscle dysregulation, and vasculopathy, characterized by progressive hypertension. PH has been reported in patients with paroxysmal nocturnal haemoglobinuria (PNH), a life-threatening haemolytic disease. We explored the relationship between haemolysis, systemic NO, arginine catabolism and measures of PH in 73 PNH patients enrolled in the placebo-controlled TRIUMPH (Transfusion Reduction Efficacy and Safety Clinical Investigation Using Eculizumab in Paroxysmal Nocturnal Haemoglobinuria) study. At baseline, intravascular haemolysis was associated with elevated NO consumption (P < 0.0001) and arginase-1 release (P < 0.0001). Almost half of the patients in the trial had elevated levels (> or =160 pg/ml) of N-terminal pro-brain natriuretic peptide (NT-proBNP), a marker of pulmonary vascular resistance and right ventricular dysfunction previously shown to indicate PH. Eculizumab treatment significantly reduced haemolysis (P < 0.001), NO depletion (P < 0.001), vasomotor tone (P < 0.05), dyspnoea (P = 0.006) and resulted in a 50% reduction in the proportion of patients with elevated NT-proBNP (P < 0.001) within 2 weeks of treatment. Importantly, the significant improvements in dyspnoea and NT-proBNP levels occurred without significant changes in anaemia. These data demonstrated that intravascular haemolysis in PNH produces a state of NO catabolism leading to signs of PH, including elevated NT pro-BNP and dyspnoea that are significantly improved by treatment with eculizumab.
Subject(s)
Antibodies, Monoclonal/therapeutic use , Dyspnea/drug therapy , Hemoglobinuria, Paroxysmal/drug therapy , Hemolysis/drug effects , Hypertension, Pulmonary/drug therapy , Nitric Oxide/deficiency , Antibodies, Monoclonal, Humanized , Biomarkers/blood , Blood Pressure/drug effects , Dyspnea/etiology , Female , Hemoglobins/metabolism , Hemoglobinuria, Paroxysmal/blood , Hemoglobinuria, Paroxysmal/complications , Hemolysis/physiology , Humans , Hypertension, Pulmonary/etiology , Hypertension, Pulmonary/physiopathology , Male , Natriuretic Peptide, Brain/blood , Peptide Fragments/blood , Treatment OutcomeABSTRACT
Recent advances in genomics include global assessment and classification of genome content, high-throughput biological pathway construction, systematic identification of previously unpredicted genes and the in vitro creation of novel motifs with biological function not found in nature (extra-genomic gene discovery). The ability to make global surveys of transcriptomes has given rise to fields such as pharmacogenomics and toxicogenomics. These applications of genomics technologies, with conventional drug assessment methodologies, will lead to more tolerable drugs and a better understanding of clinical populations. Integration of pathway mapping, using proteomics married to expression, will also significantly affect how new therapeutics are discovered as cross-biological cross-pathway interactions lead to novel drug targets and better predictions of drug tolerance.
