Pro-gastrin-releasing peptide and outcome in patients with heart failure and anaemia: results from the RED-HF study

Aims

Neuroendocrine activation is associated with poor outcome in heart failure (HF). The neuropeptide gastrin‐releasing peptide (GRP), derived from the precursor proGRP1‐125 (proGRP), has recently been implicated in inflammation and wound repair. We investigated the predictive value of proGRP on clinical outcomes in HF patients with reduced ejection fraction.

Methods and results

The association between plasma proGRP (time‐resolved immunofluorometric assay) and the primary endpoint of death from any cause or first hospitalization for worsening of HF was evaluated using multivariable Cox proportional hazard models in 1541 patients with systolic HF and mild to moderate anaemia, enrolled in the Reduction of Events by Darbepoetin alfa in Heart Failure (RED‐HF) trial. Median proGRP levels in the RED‐HF cohort were markedly increased [95 ng/L (25th, 75th percentile, 69–129 ng/L)] with 64% patients above the 80 ng/L reference limit. Baseline proGRP correlated with estimated glomerular filtration rate (r = 0.52), N terminal pro brain natriuretic peptide (r = 0.33), troponin T (r = 0.34), and haemoglobin (r = 0.16) (all P < 0.001). The incidence outcome increased with increasing tertiles of baseline proGRP (primary endpoint third tertile vs. the lowest tertile; hazard ratio 1.91; 95% confidence interval 1.60–2.28, P < 0.001). However, these associations were markedly attenuated and non‐significant in adjusted models. No interaction between baseline proGRP and the effect of darbepoetin alfa treatment was detected. Moreover, no significant association between changes in proGRP during 6 month follow‐up and outcome was observed.

Conclusions

Pro‐gastrin‐releasing peptide is increased in patients with HF with reduced ejection fraction and anaemia, in particular in patients with poor renal function. However, proGRP adds little as a prognostic marker on top of conventional HF risk factors.

Specific antibodies and sensitive immunoassays for the human epidermal growth factor receptors (HER2, HER3, and HER4)

The use of trastuzumab in patients with breast cancer that overexpresses human epidermal growth factor receptor 2 has significantly improved treatment outcomes. However, a substantial proportion of this patient group still experiences progression of the disease after receiving the drug. Evaluation of the changes in expression of the human epidermal growth factor receptors could be of interest. Monoclonal antibodies against the extracellular domain of the human growth factor receptors, 2, 3, and 4, have been raised, and specific and sensitive immunoassays have been established. Sera from healthy individuals (Nordic Reference Interval Project and Database) were analyzed in the human epidermal growth factor receptor 2 assay (N = 805) and the human epidermal growth factor receptor 3 and 4 assays (N = 114), and reference limits were calculated. In addition, sera from 208 individual patients with breast cancer were tested in all three assays. Finally, the human epidermal growth factor receptor 2 assay was compared with a chemiluminescent immunoassay for serum human epidermal growth factor receptor 2/neu. Reference values were as follows: human epidermal growth factor receptor 2, <2.5 µg/L; human epidermal growth factor receptor 3, <2.8 µg/L; and human epidermal growth factor receptor 4, <1.8 µg/L. There were significant differences in human epidermal growth factor receptor 2 and human epidermal growth factor receptor 3 serum levels between the patients with tissue human epidermal growth factor receptor 2-positive and tissue human epidermal growth factor receptor 2-negative ( p = 0.0026, p = 0.000011) tumors, but not in the serum levels of human epidermal growth factor receptor 4 ( p = 0.054). There was good agreement between the in-house human epidermal growth factor receptor 2 assay and the chemiluminescent immunoassay. Our new specific antibodies for all the three human epidermal growth factor receptors may prove valuable in the development of novel anti-human epidermal growth factor receptor targeted therapies with sensitive immunoassays for measuring serum levels of the respective targets and in monitoring established treatment.