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Purpose: Heparin-binding protein (HBP) is released by granulocytes and has been shown to increase vascular permeability in experimental investigations. Increased vascular permeability in the lungs can lead to fluid accumulation in alveoli and respiratory failure. A generalized increase in vascular permeability leads to loss of circulating blood volume and circulatory failure. We hypothesized that plasma concentrations of HBP on admission to the intensive care unit (ICU) would be associated with decreased oxygenation or circulatory failure.

Methods: This is a prospective, observational study in a mixed 8-bed ICU. We investigated concentrations of HBP in plasma at admission to the ICU from 278 patients. Simplified acute physiology score (SAPS) 3 was recorded on admission. Sequential organ failure assessment (SOFA) scores were recorded daily for three days.

Results: Median SAPS 3 was 58.8 (48-70) and 30-day mortality 64/278 (23%). There was an association between high plasma concentrations of HBP on admission with decreased oxygenation (p<0.001) as well as with circulatory failure (p<0.001), after 48-72 hours in the ICU. There was an association between concentrations of HBP on admission and 30-day mortality (p = 0.002). ROC curves showed areas under the curve of 0,62 for decreased oxygenation, 0,65 for circulatory failure and 0,64 for mortality.

Conclusions: A high concentration of HBP in plasma on admission to the ICU is associated with respiratory and circulatory failure later during the ICU care period. It is also associated with increased 30-day mortality. Despite being an interesting biomarker for the composite ICU population it's predictive value at the individual patient level is low.

BACKGROUND: There is no biomarker with high sensitivity and specificity for the development of acute kidney injury (AKI) in a mixed intensive care unit (ICU) population. Heparin-binding protein (HBP) is released from granulocytes and causes increased vascular permeability which plays a role in the development of AKI in sepsis and ischemia. The aim of this study was to investigate whether plasma levels of HBP on admission can predict the development of AKI in a mixed ICU population and in the subgroup with sepsis. METHODS: Longitudinal observational study with plasma HBP levels from 245 patients taken on admission to ICU. Presence and severity of AKI was scored daily for 1 week. RESULTS: Mean (95% CI) plasma concentrations of log HBP (ng/ml) in the groups developing different stages of AKI were: stage 0 (n = 175), 3.5 (3.4-3.7); stage 1 (n = 33), 3.7 (3.5-4.0), stage 2 (n = 20), 4.4 (3.5-4.8); and stage 3 (n = 17), 4.6 (3.8-5.2). HBP levels were significantly higher in patients developing AKI stage 3 (P < 0.01) compared to AKI stage 0 and 1. The area under the curve (AUC) for HBP to discriminate the group developing AKI stage 2-3 was 0.70 (CI: 0.58-0.82) and in the subgroup with severe sepsis 0.88 (CI: 0.77-0.99). CONCLUSION: Heparin-binding protein levels on admission to ICU are associated with the development of severe kidney injury. The relationship between HBP and AKI needs to be further validated in larger studies.

BACKGROUND: Although mechanical ventilation is often lifesaving, it can also cause injury to the lungs. The lung injury is caused by not only high pressure and mechanical forces but also by inflammatory processes that are not fully understood. Heparin-binding protein (HBP), released by activated granulocytes, has been indicated as a possible mediator of increased vascular permeability in the lung injury associated with trauma and sepsis. We investigated if HBP levels were increased in the bronchoalveolar lavage fluid (BALF) or plasma in a pig model of ventilator-induced lung injury (VILI). We also investigated if HBP was present in BALF from healthy volunteers and in intubated patients in the intensive care unit (ICU).

METHODS: Anaesthetized pigs were randomized to receive ventilation with either tidal volumes of 8 ml/kg (controls, n = 6) or 20 ml/kg (VILI group, n = 6). Plasma and BALF samples were taken at 0, 1, 2, 4, and 6 h. In humans, HBP levels in BALF were sampled from 16 healthy volunteers and from 10 intubated patients being cared for in the ICU.

RESULTS: Plasma levels of HBP did not differ between pigs in the control and VILI groups. The median HBP levels in BALF were higher in the VILI group after 6 h of ventilation compared to those in the controls (1144 ng/ml (IQR 359-1636 ng/ml) versus 89 ng/ml (IQR 33-191 ng/ml) ng/ml, respectively, p = 0.02). The median HBP level in BALF from healthy volunteers was 0.90 ng/ml (IQR 0.79-1.01 ng/ml) as compared to 1959 ng/ml (IQR 612-3306 ng/ml) from intubated ICU patients (p < 0.001).

CONCLUSIONS: In a model of VILI in pigs, levels of HBP in BALF increased over time compared to controls, while plasma levels did not differ between the two groups. HBP in BALF was high in intubated ICU patients in spite of the seemingly non-harmful ventilation, suggesting that inflammation from other causes might increase HBP levels.

BACKGROUND: Heparin-binding protein (HBP) is released by neutrophils upon activation, and elevated plasma levels are seen in inflammatory states like sepsis, shock, cardiac arrest, and burns. However, little is known about the elimination of HBP. We wanted to study renal clearance of HBP in healthy individuals and in burn patients in intensive care units (ICUs). We also wished to examine the levels of HBP in the effluent of renal replacement circuits in ICU patients undergoing continuous renal replacement therapy (CRRT).

METHODS: We measured plasma and urine levels of HBP and urine flow rate in 8 healthy individuals and 20 patients in a burn ICU. In 32 patients on CRRT, we measured levels of HBP in plasma and in the effluent of the CRRT circuit.

RESULTS: Renal clearance of HBP (median (IQR) ml/min) was 0.19 (0.08-0.33) in healthy individuals and 0.30 (0.01-1.04) in burn ICU patients. In ICU patients with cystatin C levels exceeding 1.44 mg/l, clearance was 0.45 (0.15-2.81), and in patients with cystatin C below 1.44 mg/l clearance was lower 0.28 (0.14-0.55) (p = 0.04). Starting CRRT did not significantly alter plasma levels of HBP (p = 0.14), and the median HBP level in the effluent on CRRT was 9.1 ng/ml (IQR 7.8-14.4 ng/ml).

CONCLUSION: In healthy individuals and critically ill burn patients, renal clearance of HBP is low. It is increased when renal function is impaired. Starting CRRT in critically ill patients does not alter plasma levels of HBP significantly, but HBP can be found in the effluent. It seems unlikely that impaired kidney function needs to be considered when interpreting concentrations of HBP in previous studies. Starting CRRT does not appear to be an effective way of reducing HBP concentrations.