Leukocyte depletion does not affect the in vitro healing ability of platelet rich plasma

The clinical use of platelet-rich plasma (PRP) containing or deprived of leukocytes remains a subject of debate and a controversial issue. It is not yet clear whether leukocyte content has a positive or negative effect on tissue healing processes. Several studies, conducted mainly in the orthopedic field, support the use of leukocyte-poor (LP) PRP, whereas other studies have not identified any significant differences between the use of LP and leukocyte-rich PRP. In the present study, the role of leukocytes contained in PRP was assessed to verify their in vitro effect on fibroblasts and endothelial cells, which have a leading role in the biological processes associated with wound healing (including angiogenesis and matrix remodeling). The original sample of PRP was divided into two aliquots, one of which remained unaltered, while the other was deprived of leukocytes. The two aliquots were used in in vitro tests in order to verify the effects of leukocytes on proliferation, wound healing and tube formation, and in molecular analyses of growth factor and enzyme content. The present results highlighted a substantial overlap between the two formulations. This may be explained by similar levels of growth factors (vascular endothelial growth factor, thrombospondin-1, interferon-γ, platelet-derived growth factor-BB, -AA and -B, tumor growth factor-β1, fibroblast growth factor 7 and tumor necrosis factor-α) and enzymes (gelatinases and plasminogen activators) in the two formulations. These results support the hypothesis that the ability of the PRP to affect the in vitro biological response of endothelial cells and fibroblasts does not rely on the presence of leukocytes.

The potential of the novel leukocyte removal filter in cardiopulmonary bypass

Cardiopulmonary bypass (CPB) is indispensable for cardiac surgery but leads to systemic inflammatory responses and leukocyte activation, possibly due to blood contact with the surface of the CPB unit, surgical, ischemic reperfusion injury, etc. Systemic inflammatory responses during CPB result in increased morbidity and mortality. Activation of leukocytes is an important part of this process and directly contributes to coagulopathy and hemorrhage. This inflammatory response may contribute to the development of postoperative complications, including myocardial dysfunction, respiratory failure, renal and neurologic dysfunction, altered liver function and ultimately, multiple organ failure. Various pharmacologic and mechanical strategies have been developed to minimize the systemic inflammatory response during CPB. For example, leukocyte removal filters were developed in the 1990s for incorporation into the CPB circuit. However, studies of this approach have yielded conflicting findings. The purpose of this was to review the studies of a novel leukocyte removal filter in patients undergoing CPB.

Oxidative stress and related metabolic alterations are induced in ex situ perfusion of donated hearts regardless of the ventricular load or leukocyte depletion

We sought to determine the role of donor blood circulating leukocytes in mediating oxidative stress and inflammation during normothermic ex situ heart perfusion (ESHP). Normothermic ESHP allows preservation of donated heart in a perfused, dynamic state, preventing ischemia. However, the cardiac function declines during ESHP, limiting the potential of this method for improvement of the outcomes of transplantation and expanding the donor pool. Extracorporeal circulation-related oxidative stress plays a critical role in the functional decline of the donor heart. Hearts from domestic pigs were perfused in working mode (WM, whole blood-based or leukocyte-depleted blood-based perfusate) or nonworking mode. Markers of oxidative stress and responsive glucose anabolic pathways were induced in the myocardium regardless of left ventricular load. Myocardial function during ESHP as well as cardioprotective mechanisms were preserved better in WM. Leukocyte-depleted perfusate did not attenuate tissue oxidative stress or perfusate proinflammatory cytokines and did not improve functional preservation. Although ESHP is associated with ongoing oxidative stress and metabolic alteration in the myocardium, preserved cardioprotective mechanisms in WM may exert beneficial effects. Leukocyte depletion of the perfusate may not attenuate inflammation and oxidative stress effectively or improve the functional preservation of the heart during ESHP.

Use of leukocyte-depleting filters during cardiac surgery with cardiopulmonary bypass: a review

Numerous researchers and clinicians have shown that cardiopulmonary bypass (CPB) plays a large role in the initiation of the systemic inflammatory response during cardiac surgery. The activation of leukocytes during this process has been implicated as one of the major contributors to multi-organ dysfunction experienced by some patients after cardiac surgery. Thus, in an attempt to attenuate the systemic inflammatory response and to reduce the amount of activated leukocytes from the systemic circulation during CPB, leukocyte-depleting filters were developed in the early 1990s. Since the clinical introduction of these filters into the CPB circuit, several articles have been published evaluating the effectiveness of leukocyte filtration; however, the results have been conflicting. This article will review some of the most recent literature, approximately 40 papers published within the past 10 years, regarding the use of leukocyte-depleting filters during CPB and its effectiveness in preserving organ function. In addition, the effect of different filtration strategies and the effectiveness of the filter to attenuate the systemic inflammatory response in combination with other mechanical and pharmaceutical strategies will be reviewed.

Safety and performance of the Spectra Optia apheresis system for white blood cell depletion in patients with elevated white blood cell counts

BACKGROUND

For the past 30 years, white blood cell depletion (WBCD) or leukocytapheresis has been conducted to rapidly reduce excessive circulating white blood cell (WBC) concentrations in patients at risk for or with symptoms of leukostasis due to hyperleukocytosis. The goal of leukocytapheresis is to prevent or treat acute complications from leukostasis, thereby enabling patients to receive potentially curative chemotherapy.

METHODS

This report details the results from a retrospective and a prospective clinical study conducted in the European Union and the People's Republic of China, which assessed the use of the Spectra Optia Apheresis System for leukocytapheresis in patients with hyperleukocytosis. The primary objective of both studies was to the assess the safety and performance of the WBCD procedure in patients with elevated WBC counts.

RESULTS

Data were collected from 72 participants completing 87 WBCD procedures. The mean percent change in participant WBC counts post-procedure was 50.3 ± 21.2% and the collection efficiency (CE1) of the WBCD procedures was 53.7 ± 19.8%. Sixty-one participants (95.3%) experienced a total of 279 adverse events (AEs) with the majority of the AEs related to post-procedure changes in laboratory values, which is an anticipated AE in this patient population.

CONCLUSION

The data collected within these studies indicate that the WBCD procedure is safe and well tolerated in patients with hyperleukocytosis as evaluated by percent decrease in WBC count, CE1, and AE incidence.

The abrogated role of premedication in the prevention of transfusion-associated adverse reactions in outpatients receiving leukocyte-reduced blood components

BACKGROUND AND OBJECTIVES

Although it remains controversial, premedication before transfusion is a common clinical practice to prevent transfusion-associated adverse reactions (TAARs) in Taiwan. Thus, we aimed to investigate whether premedication prevented outpatients from developing TAARs and whether an educational programme could improve the understanding of physicians related to the unnecessary use of premedication, and this could elicit changes in their prescribing activities without affecting the occurrence of TAARs.

MATERIALS AND METHODS

Clinical data from outpatients receiving transfusion therapy, including predisposing diseases, histories of transfusion and TAARs, premedication and the occurrence of TAARs in the period April 2017 to October 2018, were retrospectively obtained. The evidence-based transfusion programme implemented to educate physicians was started in January 2018.

RESULTS

A total of 5018 blood units were transfused to 803 outpatients, with 2493 transfusion events reported in the study interval. The most frequently transfused component was leukocyte-reduced packed red cells (n = 4338), followed by leukocyte-reduced apheresis platelets (n = 540) and other blood components. The overall premedication rate significantly decreased from 92.4% to 76.7% after the educational programme (p < 0.001). There was no remarkable change in the occurrence of TAARs per patient event between the periods before and after the educational programme (1.11% vs. 1.14%, p = 0.964). Besides, it was shown that the occurrence of TAARs was associated with the history of TAARs and inversely related to multiple transfusions, but not premedication.

CONCLUSION

Decreased premedication was not associated with increased incidence of TAARs in outpatients; these findings provide important evidence to support the need to revise clinical practices in the era of leukocyte-reduced blood products.