The Italian registry of therapeutic apheresis in SISTRA: Year of activity 2022.

Therapeutic apheresis refers to a group of extracorporeal blood processing procedures used in the treatment of a variety of systemic diseases. These complex procedures are burdened by adverse reactions related to both procedures and underlying medical conditions. Given the importance of centralizing the collection and the analysis of information on therapeutic apheresis, the Italian National Blood Center (NBC), at the request of the Italian Scientific Society of Hemapheresis and Cell Manipulation (SIdEM), implemented the Italian Registry of Therapeutic Apheresis (IRTA) including it in the Information System of Transfusion Services (SISTRA), coordinated by the NBC. In 2022, a total of 34,702 therapeutic apheresis procedures was carried out in 8,781 patients, including paediatric patients, with an average of 3.9 procedures per patient. The 2022 IRTA data indicate that the patient with hematological and/or neurological disorders mainly turns to the apheresis centers. These results confirm the IRTA data from years 2020 and 2021. In the hematological field, the apheresis centers supply hematopoietic stem cells collection for autologous transplantation as well as mononuclear cell collection for extracorporeal photopheresis. With regard to the neurological field, myasthenia, chronic inflammatory demyelinating polyneuropathy and Guillain-Barré syndrome along with other neurological pathologies related to immune disorders are the most treated. In conclusion, this manuscript presents 2022 activity data of IRTA providing institutions and scientific societies with a wide range of information including type and number of therapeutic procedures, adverse events and patients' outcome.

The Italian registry of therapeutic apheresis: year of activity 2021.

In 2019, the Italian National Blood Center (NBC), at the request of the Italian Scientific Society of Haemapheresis and Cell Manipulation (SIdEM), included the Italian Registry of Therapeutic Apheresis (IRTA) in the Information System of Transfusion Services (SISTRA), whose activity is coordinated by the NBC. The IRTA provides institutions and scientific societies with a wide range of information including therapeutic procedures and outcomes of treated patients. The Italian National Health Service offers therapeutic apheresis for patients with various conditions, but it is mainly the patient with haematological and/or neurological disorders who turns to the apheresis centres as evidenced by the activity data of 2021. In the haematological field, the apheresis centres mainly supply haematopoietic stem cells for autologous or allogeneic transplantation as well as mononuclear cell collection for extracorporeal photopheresis (ECP), a therapeutic approach of II line in post-transplant Graft versus Host Disease. The activity of 2021 in the neurological field confirms the data of 2019, the pre-pandemic year, and indicates that myasthenia, chronic inflammatory demyelinating polyneuropathy and Guillain-Barré syndrome along with other neurological pathologies related to immune disorders are the diseases in which apheresis procedures are most used. In conclusion, the IRTA is a valuable tool for monitoring the activity of apheresis centres carried out at a national level and above all for providing an overall picture of how the use of this therapeutic tool evolves and changes over time.

The Italian registry of therapeutic apheresis enters the information system of transfusion services - SISTRA.

The National Blood Centre (NBC) at the request of the Italian Scientific Society of Haemapheresis and Cell Manipulation (SIdEM) has funded and developed a software dedicated to the collection of data related to therapeutic apheresis procedures, known as the Italian Registry of Therapeutic Apheresis (IRTA). Although on a voluntary basis, participation in the registry was widespread. The data collected includes type and number of procedures, patients treated and their outcomes, and reported adverse events to the procedures. For the years 2019 and 2020, the therapeutic apheresis procedure was widely used in the field of haematology, transplantation and rheumatology and was mainly associated with mild adverse events, thus showing a high level of safety. In addition to allowing the competent institution to monitor an important activity in the transfusion medicine field, the Registry is a new starting point for collaboration between transfusion centres distributed throughout the national territory and could encourage the design of major clinical trials.

ß-blockers Reverse Agonist-Induced ß2-AR Downregulation Regardless of Their Signaling Profile.

Altered ß-adrenergic receptor (ß-AR) density has been reported in cells, animals, and humans receiving ß-blocker treatment. In some cases, ß-AR density is upregulated, but in others, it is unaffected or even reduced. Collectively, these results would imply that changes in ß-AR density and ß-blockade are not related. However, it has still not been clarified whether the effects of ß-blockers on receptor density are related to their ability to activate different ß-AR signaling pathways. To this aim, five clinically relevant ß-blockers endowed with inverse, partial or biased agonism at the ß2-AR were evaluated for their effects on ß2-AR density in both human embryonic kidney 293 (HEK293) cells expressing exogenous FLAG-tagged human ß2-ARs and human lymphocytes expressing endogenous ß2-ARs. Cell surface ß2-AR density was measured by enzyme-linked immunosorbent assay (ELISA) and flow cytometry. Treatment with propranolol, carvedilol, pindolol, sotalol, or timolol did not induce any significant change in surface ß2-AR density in both HEK293 cells and human lymphocytes. On the contrary, treatment with the ß-AR agonist isoproterenol reduced the number of cell surface ß2-ARs in the tested cell types without affecting ß2-AR-mRNA levels. Isoproterenol-induced effects on receptor density were completely antagonized by ß-blocker treatment. In conclusion, the agonistic activity of ß-blockers does not exert an important effect on short-term regulation of ß2-AR density.

The Role of ABO Blood Type in Thrombosis Scoring Systems.

In addition to their major role in transfusion medicine, there is increasing evidence that ABO blood group antigens (complex carbohydrate molecules widely expressed on the surface of red blood cells and several other cell types) are implicated in the development of a wide array of pathologic conditions. In particular, intense research has been dedicated over the last 50 years to the study of the association between non-O blood type and the risk of developing cardiovascular disorders. Several pathways have been hypothesized to explain this relationship, the most reasonable implying the influence of the ABO blood group on circulating plasma levels of von Willebrand factor, factor VIII, and several inflammatory cytokines. This narrative review summarizes the current knowledge on the role of ABO antigens in both venous and arterial thromboses, focusing on their association with clinical scoring systems evaluating thrombotic risk.

Human T-lymphotropic virus and transfusion safety: does one size fit all?

Human T-cell leukemia viruses (HTLV-1 and HTLV-2) are associated with a variety of human diseases, including some severe ones. Transfusion transmission of HTLV through cellular blood components is undeniable. HTLV screening of blood donations became mandatory in different countries to improve the safety of blood supplies. In Japan and Europe, most HTLV-infected donors are HTLV-1 positive, whereas in the United States a higher prevalence of HTLV-2 is reported. Many industrialized countries have also introduced universal leukoreduction of blood components, and pathogen inactivation technologies might be another effective preventive strategy, especially if and when generalized to all blood cellular products. Considering all measures available to minimize HTLV blood transmission, the question is what would be the most suitable and cost-effective strategy to ensure a high level of blood safety regarding these viruses, considering that there is no solution that can be deemed optimal for all countries.

ß-Blockers promote angiogenesis in the mouse aortic ring assay.

Recent results indicate that the reduction of ß-adrenergic signaling impairs angiogenesis under ischemic conditions. Because angiogenesis may occur in the absence of ischemia, it remains to be determined whether and how ß-adrenergic signaling regulates angiogenesis, which develops under normoxic conditions. The effect of ß-adrenergic ligands on angiogenesis was investigated using 3-dimensional cultures of mouse aortic rings embedded in collagen type I, in which luminized microvessels develop in response to vascular endothelial growth factor (VEGF). Under normoxic conditions, both isoproterenol, a ß-adrenergic receptor (ß-AR) agonist, and forskolin, an adenylate cyclase activator, were unable to influence aortic microvessel sprouting. On the contrary, treatment with propranolol, a ß-AR antagonist, caused an approximately 70% increase in VEGF-mediated microvessel sprouting. This effect was abolished in rings from both double ß-AR and ß1-AR knockout mice, but not in rings from ß2-AR knockout mice. Significant increases in microvessel sprouting were also observed when mouse aortic rings from C57BL/6 mice were treated with the ß1-AR-selective antagonists metoprolol and bisoprolol or with the ß2-AR-selective antagonist ICI 118,551. Conversely, carvedilol, a nonselective ß-AR antagonist, was unable to affect aortic sprouting. These findings suggest that some ß-blockers display proangiogenic activity through a mechanism that is independent of their ability to antagonize catecholamine action. The present results also identify a new function for ß-AR signaling as a facilitator for VEGF-mediated angiogenesis and have implications for understanding the mechanisms that regulate angiogenic responses under normoxic conditions.

Benzodiazepine diazepam regulates cell surface ß1-adrenergic receptor density in human monocytes.

Downregulation of cell surface ß-adrenergic receptors (ß-AR) is an important adaptive response that prevents deleterious effects of receptor overstimulation. Various factors including reactive oxygen species cause ß-AR downregulation. In this study, we evaluated the effects of ligands of the peripheral benzodiazepine receptor (PBR), a key protein in regulating oxidative stress, on surface density of endogenous ß1-and ß2-ARs in highly differentiated cells such as human monocytes, which express both ß-AR subtypes. ß-AR expression in human monocytes was evaluated by flow cytometry, qPCR and western blotting. Monocyte treatment with ß-AR agonist isoproterenol did not change surface ß1-AR density while downregulating surface ß2-AR density. This effect was antagonized by the ß-blocker propranolol. An opposite response was observed with benzodiazepine diazepam that led to a time-dependent reduction in ß1-AR density. In particular, while no significant downregulation was observed after 3 h of treatment, only 63% of ß1-ARs were still present on the cell surface after 48 h of treatment with diazepam at 1 µM. Treatment with the PBR antagonist PK11195, but not with propranolol, antagonized the effects of diazepam. No change in ß1-AR-mRNA or protein levels was observed at any time after diazepam treatment. We also found that diazepam did not affect Gs-protein or ß-arrestin-2 recruitment for both ß-ARs in engineered fibroblasts, further suggesting that diazepam activity on ß1-AR density is mediated by PBR. Finally, no sex-related differences were found. Collectively, these results indicate that monocyte ß1-ARs are resistant to catecholamine-mediated downregulation and suggest that PBR plays an important role in regulating ß1-AR density.

α-Adrenoceptor stimulation attenuates melanoma growth in mice.

BACKGROUND AND PURPOSE: Recently, ß-adrenoceptor blockade has emerged as a potential strategy to inhibit melanoma growth. It remains to be ascertained whether ß-adrenoceptor stimulation by circulating catecholamines increases melanoma growth in mice. EXPERIMENTAL APPROACH: B16F10 melanoma-bearing mice were used to evaluate effects of adrenaline and specific adrenoceptor (AR) ligands on tumour volume. AR expression and effects of AR ligands on cell viability, production of mitochondrial reactive oxygen species (mROS), and proliferation activity in B16F10 cells, were determined by biochemical analyses. KEY RESULTS: Real-time polymerase chain reaction (qPCR) analyses revealed that B16F10 cells express α1B-, α2A-, α2B- and ß2-ARs. We found that treatment with the α- and ß-AR agonist adrenaline or with the synthetic catecholamine isoprenaline, which selectively stimulates ß-ARs, did not affect melanoma growth. Conversely, adrenaline reduced tumour growth in mice cotreated with propranolol, a ß1ß2-AR antagonist. Adrenaline had no effect in tumour-bearing ß1ß2-AR knockout mice, in which ß1- and ß2-ARs are lacking, but it reduced tumour growth when co-administered with propranolol suggesting that tumour ß2-ARs negatively regulate adrenaline antitumour activity. Additionally, we found that α1-AR stimulation with cirazoline yielded a decrease in B16F10 melanoma size. These effects on melanoma growth were paralleled by reduced cell viability and proliferation activity as well as increased mROS production in α1-AR-stimulated B16F10 cells. Decreased viability, proliferation and mitochondrial function in B16F10 cells also occurred after α2-AR stimulation by α2-AR agonist ST91. CONCLUSIONS AND IMPLICATIONS: In the B16F10 melanoma model, stimulation of α-AR subtypes yields in vivo and in vitro anticancer activity.

Vasovagal reactions in whole blood and apheresis donors: a cross-sectional study on donor haemovigilance data from 2016 to 2019 in Italy.

BACKGROUND: Acute and delayed vasovagal reactions (VVR) are the most frequent adverse reactions (AR) associated with donations. The aim of this study was to provide the data of the Italian donor haemovigilance system and contextualise the VVR data within the international framework, as well as evaluating, among first-time donors, the association of gender and age and the prevalence of VVR compared to other AR. MATERIALS AND METHODS: The prevalence analysis was performed on VVR and other AR notified to the Italian haemovigilance system from 2016 to 2019. The analysis on the association of gender and age group and VVR prevalence was performed on first-time donations. The definitions and severity of AR were as set out in the 2014 ISBT/IHN international standards. RESULTS: From 2016 to 2019, 34,519 AR were notified, of which 87.1% were VVR. The overall VVR prevalence was 25.0/10,000 donations and the overall prevalence of other AR was 3.7/10,000 donations. All the estimated prevalences of AR were higher for first-time donations than for regular donations and lower for whole blood than for apheresis donations. No difference was noted between whole blood and apheresis donations for VVR with complications or injuries. The prevalence of AR among first-time donors was higher in females than in males. The prevalence of VVR decreased as donor age increased. DISCUSSION: The prevalence of VVR related to blood donation was very low and similar to those calculated by other haemovigilance systems. Among first-time donors, the prevalence of AR was higher in females than in males. The higher prevalence of VVR in young donors and a significant decreasing trend by age group confirmed the results reported in the literature. Finally, no trend by age group in first-time donors was observed for other AR to donations.

Intermittent ß-adrenergic blockade downregulates the gene expression of ß-myosin heavy chain in the mouse heart.

Expression of the ß-myosin heavy chain (ß-MHC), a major component of the cardiac contractile apparatus, is tightly regulated as even modest increases can be detrimental to heart under stress. In healthy hearts, continuous inhibition of ß-adrenergic tone upregulates ß-MHC expression. However, it is unknown whether the duration of the ß-adrenergic inhibition and ß-MHC expression are related. Here, we evaluated the effects of intermittent ß-blockade on cardiac ß-MHC expression. To this end, the ß-blocker propranolol, at the dose of 15mg/kg, was administered once a day in mice for 14 days. This dosing schedule caused daily drug-free periods of at least 6 h as evidenced by propranolol plasma concentrations and cardiac ß-adrenergic responsiveness. Under these conditions, ß-MHC expression decreased by about 75% compared to controls. This effect was abolished in mice lacking ß1- but not ß2-adrenergic receptors (ß-AR) indicating that ß-MHC expression is regulated in a ß1-AR-dependent manner. In ß1-AR knockout mice, the baseline ß-MHC expression was fourfold higher than in wild-type mice. Also, we evaluated the impact of intermittent ß-blockade on ß-MHC expression in mice with systolic dysfunction, in which an increased ß-MHC expression occurs. At 3 weeks after myocardial infarction, mice showed systolic dysfunction and upregulation of ß-MHC expression. Intermittent ß-blockade decreased ß-MHC expression while attenuating cardiac dysfunction. In vitro studies showed that propranolol does not affect ß-MHC expression on its own but antagonizes catecholamine effects on ß-MHC expression. In conclusion, a direct relationship occurs between the duration of the ß-adrenergic inhibition and ß-MHC expression through the ß1-AR.

Prevalence, incidence and residual risk of transfusion-transmitted hepatitis B virus infection in Italy from 2009 to 2018.

BACKGROUND: In Italy, the use of nucleic acid testing for hepatitis B virus (HBV) in donor screening has allowed the detection of infections in the window phase, as well as the presence of occult infections which could potentially be transmitted. The aim of this study was to analyse the trends of epidemiological data focused on HBV infection in blood donors and to estimate the residual risk of transmitting HBV from both the window phase and occult infection over a 10-year period in Italy. MATERIALS AND METHODS: Data were obtained from the Italian Haemovigilance System which includes the results of screening tests for transfusion transmissible infections. During the period of this survey (2009-2018), the molecular methods used for HBV screening were transcription-mediated amplification and polymerase chain reaction tests. Prevalence and incidence were calculated. The residual risk was estimated by applying the incidence-window period model for acute cases and a more recently reported model for estimating the risk due to occult infections. RESULTS: A total of 17,424,535 blood donors and 30,842,794 donations were tested for HBV. Altogether, 6,250 donors tested positive for HBV markers: 4,782 (175.6×105) were first time donors and 1,468 (10.0×105) were repeat donors. The prevalence of HBV markers in first time donors was 275.9×105 in 2009, declining to 143.6×105 in 2018. The incidence of new infections was 3.37×105 in 2009 and 2.17×105 in 2018. The overall residual risk for HBV amounted to 1 in 2,566,854 donations calculated as the sum of risks of both acute infections in the window period (1 in 5,835,306 donations) and occult infections (1 in 4,582,270 blood units). DISCUSSION: In Italy, the residual risk of transfusing a blood unit infected with HBV, both from window phase and occult infections, is currently very low, amounting to levels that can be considered tolerable.

Patient Blood Management: a revolutionary approach to transfusion medicine.

Patient Blood Management (PBM) is a multimodal, multidisciplinary approach adopted to limit the use and the need for allogeneic blood transfusion in all at-risk patients with the aim of improving their clinical outcomes. Although PBM usually refers to surgical patients, its clinical use has gradually evolved over the last few years and it now also refers to medical conditions. This review will critically analyse the current knowledge on the use of PBM programmes in surgical and non-surgical patients.

Emicizumab for the treatment of haemophilia A: a narrative review.

One of the most serious complications of the treatment of severe haemophilia A is the development of alloantibodies against exogenous factor VIII (FVIII). Inhibitors render factor replacement therapy ineffective, exposing patients to a remarkably high risk of morbidity and mortality. Besides the well-known bypassing agents (i.e. activated prothrombin complex concentrate and recombinant activated factor VII) used to treat or prevent bleeding in haemophilia patients with inhibitors, there is growing interest in newer haemostatic therapies that are not based on the replacement of the deficient FVIII. This review will focus on the most interesting among these innovative therapies, emicizumab, and will provide an update on its current stage of clinical development.

cAMP-mediated beta-adrenergic signaling negatively regulates Gq-coupled receptor-mediated fetal gene response in cardiomyocytes.

The treatment with beta-blockers causes an enhancement of the norepinephrine-induced fetal gene response in cultured cardiomyocytes. Here, we tested whether the activation of cAMP-mediated beta-adrenergic signaling antagonizes alpha(1)-adrenergic receptor (AR)-mediated fetal gene response. To address this question, the fetal gene program, of which atrial natriuretic peptide (ANP) and the beta-isoform of myosin heavy chain are classical members, was induced by phenylephrine (PE), an alpha(1)-AR agonist. In cultured neonatal rat cardiomyocytes, we found that stimulation of beta-ARs with isoproterenol, a beta-AR agonist, inhibited the fetal gene expression induced by PE. Similar results were also observed when cardiomyocytes were treated with forskolin (FSK), a direct activator of adenylyl cyclase, or 8-CPT-6-Phe-cAMP, a selective activator of protein kinase A (PKA). Conversely, the PE-induced fetal gene expression was further upregulated by H89, a selective PKA inhibitor. To evaluate whether these results could be generalized to Gq-mediated signaling and not specifically to alpha(1)-ARs, cardiomyocytes were treated with prostaglandin F(2)alpha, another Gq-coupled receptor agonist, which is able to promote fetal gene expression. This treatment caused an increase of both ANP mRNA and protein levels, which was almost completely abolished by FSK treatment. The capability of beta-adrenergic signaling to regulate the fetal gene expression was also evaluated in vivo conditions by using beta1- and beta2-AR double knockout mice, in which the predominant cardiac beta-AR subtypes are lacking, or by administering isoproterenol (ISO), a beta-AR agonist, at a subpressor dose. A significant increase of the fetal gene expression was found in beta(1)- and beta(2)-AR gene deficient mice. Conversely, we found that ANP, beta-MHC and skACT mRNA levels were significantly decreased in ISO-treated hearts. Collectively, these data indicate that cAMP-mediated beta-adrenergic signaling negatively regulates Gq cascade activation-induced fetal gene expression in cultured cardiomyocytes and that this inhibitory regulation is already operative in the mouse heart under physiological conditions.

Propranolol promotes Egr1 gene expression in cardiomyocytes via beta-adrenoceptors.

Recent research has revealed that propranolol, a beta-adrenoceptor antagonist, causes extracellular signal-regulated kinase (ERK) cascade activation, nuclear translocation of phospho-ERK and increased transcriptional activity in cultured cell lines. Given the importance of beta-adrenoceptor antagonists in the treatment of heart failure, we evaluated the capability of propranolol of promoting the ERK-dependent gene expression at the cardiomyocyte level. To this end, the gene expression of the early growth response factor 1 (Egr1), a well-recognized indicator of nuclear extracellular signal-regulated kinase 1/2 (ERK1/2) activation, was assessed by quantitative real-time RT-PCR in vivo as well as in vitro experiments. Propranolol, administered at the dose of 10 mg/kg/day in C57BL/6 mice, caused a approximately 19-fold increase of Egr1 mRNA expression in left ventricular myocardium along with a approximately 2.1-fold increase of Egr1 protein expression. Isoproterenol, a nonselective beta-adrenoceptor agonist, also increased Egr1 mRNA and protein expression but to a lesser degree. Remarkably, isoproterenol administration was associated with the development of cardiac hypertrophy, whereas propranolol-treated mice showed a completely normal cardiac morphology. The effect of propranolol on Egr1 mRNA expression was abrogated in mice lacking beta(1)- and beta(2)-adrenoceptors indicating that propranolol increases Egr1 mRNA expression in a beta-adrenoceptor-dependent manner. The role of beta-adrenoceptors was further confirmed by showing that propranolol was able to increase Egr1 mRNA and protein levels in cultured neonatal cardiomyocytes. Collectively, these results indicate that propranolol promotes Egr1 gene expression in cardiomyocytes via beta-adrenoceptors with a mechanism which is independent of its ability to antagonize the effects of catecholamines. It is also suggested that cardiomyocyte growth and Egr1 gene overexpression are not obligate processes.

Rare congenital bleeding disorders.

The rare congenital bleeding disorders are a heterogeneous group of diseases which include deficiencies of fibrinogen, prothrombin and factors V, V + VIII, VII, X, XI and XIII. They are usually transmitted as autosomal recessive disorders, and the prevalence of the severe forms ranges from one case in 500,000 for factor VII up to one in 2,000,000 for factor XIII in the general population. Patients with rare congenital bleeding disorders may have a broad spectrum of clinical symptoms, ranging from mucocutaneous bleeding to life-threatening haemorrhages, such as those occurring in the central nervous system. The treatment of these disorders is based principally on the replacement of the deficient factor using, when available, specific plasma-derived or recombinant products. The aim of this narrative review is to summarise current knowledge about these rare bleeding conditions.

Prevalence, incidence and residual risk of transfusion-transmitted hepatitis C virus and human immunodeficiency virus after the implementation of nucleic acid testing in Italy: a 7-year (2009-2015) survey.

BACKGROUND: In Italy nucleic acid testing (NAT) became mandatory for hepatitis C virus (HCV) in 2002 and for human immunodeficiency virus (HIV) and hepatitis B virus in 2008. The aim of this study was to monitor the incidence and prevalence of HIV and HCV infections in Italian blood donors and the current residual risk of these infections after the introduction of NAT. MATERIALS AND METHODS: The Italian national blood surveillance system includes data from tests used to screen for transfusion-transmissible infections. During the period of this survey (2009-2015), the NAT methods used were the transcription-mediated amplification test, for individual donor testing, and polymerase chain reaction analysis, mainly for pools of six donors. Prevalence and incidence were calculated. Three published formulae were applied to estimate the residual risk (the window period ratio model and the formulae recommended by the European Medicines Agency and the World Health Organization). RESULTS: Overall, 12,258,587 blood donors and 21,808,352 donations were tested for HCV and HIV. The prevalence of HCV decreased from 110.3×105 to 58.9×105 in years 2009 and 2015, respectively, while that of HIV remained stable over time (15.5×105 vs 15.4×105). The incidence of HCV decreased from 3.19×105 in 2009 to 1.58×105 in 2015, while the incidence of HIV did not show any significant fluctuations (average incidence 4.39×105). The residual risk of a viraemic unit entering the blood supply was estimated to be 0.077×106 or 1 in 12,979,949 donations for HCV and 0.521×106 or 1 in 1,917,250 for HIV, according to the window period ratio model, and lower with the other two formulae. DISCUSSION: HCV infection has declined over time in both first-time and repeat donors, while the data for HIV infection are stable. All three methods employed in this study showed that the residual risk of transmitting HCV or HIV through an infected blood unit is currently very low in Italy, but there are considerable differences in estimates between methods. Thus, harmonisation of these methods is advisable.

The management of a blood donor bitten by a snake.

The worldwide burden of snakebite is high and venomous snakes are found in many regions of the world and are a threat to public health. In Italy, for instance, viper bites are an infrequent but not negligible event. Although people who have been bitten by a snake rarely wish to donate blood within a "short" time, it is however important to evaluate their eligibility to donate blood or blood components as their donation could be a problem for donor management, especially if a specific policy is not in place. The aim of this manuscript is to summarise the worldwide existing donor deferral policy for snakebites and to provide some indications in order to facilitate decision-making and to guarantee maximum safety for the donors as well as for the recipients.

Biphasic effects of propranolol on tumour growth in B16F10 melanoma-bearing mice.

BACKGROUND AND PURPOSE: Propranolol is a vasoactive drug that shows antiangiogenic and antitumour activities in melanoma. However, it is unknown whether these activities are dose-dependent and whether there is a relationship between systemic vascular effects of propranolol and anti-melanoma activity. EXPERIMENTAL APPROACH: Effects of increasing doses of propranolol (10, 20, 30 and 40 mg·kg-1 ·day-1 ) on tumour growth were studied in B16F10 melanoma-bearing mice. Histological and biochemical analyses were used to assess propranolol effects on angiogenesis and cancer cell proliferation. Systemic vascular resistance (SVR) was evaluated by measuring cardiac output and arterial BP. KEY RESULTS: In vitro analyses revealed that B16F10 cells expressed ß-adrenoceptors, but neither isoprenaline, a ß-adrenoceptor agonist, nor the ß-blocker propranolol affected cancer cell proliferation. In vivo studies showed that the antitumour efficacy of propranolol follows a U-shaped biphasic dose-response curve. Low doses (10 and 20 mg·kg-1 ·day-1 ) significantly inhibit tumour growth, whereas higher doses are progressively less effective. We also found that high-dose propranolol stimulates tumour arteriogenesis whereas no effect on angiogenesis was observed at any dose. Based on these data and considering that propranolol is a vasoactive drug, we hypothesized that it causes systemic vasoconstriction or vasodilation depending on the dose and thus alters tumour perfusion and growth. Consistent with this hypothesis, we found that propranolol has a biphasic effect on SVR with low and high doses producing vasoconstriction and vasodilation respectively. CONCLUSIONS AND IMPLICATIONS: Propranolol inhibits melanoma growth in a U-shaped biphasic manner. A direct relationship exists between SVR and anti-melanoma activity.