COVID-19: A case for plasma derived natural anticoagulants?

Convalescent plasma was proposed for passive immunization against COVID-19; but so far there are conflicting results and still open questions. However, besides antibodies, other plasma proteins may be good candidates for further research and application. Thromboinflammation frequently complicates severe COVID-19, and classical anticoagulants like heparins seem to have limited effect. The natural protease inhibitors antithrombin III (ATIII), α1-antitrypsin (α1-AT) and α2-macroglobulin (α2-M), which are found decreased in severe COVD-19, play a crucial role in prothrombotic and inflammatory pathways. While ATIII and α1-AT are licensed as commercially prepared therapeutic concentrates, there is no preparation of α2-M available. The diagnostic, prognostic, and even therapeutic potential of plasma protease inhibitors should be further explored.

Prethrombin-1 as a Drug Substance Promoting Hemostasis with Reduced Risk of Thrombosis.

INTRODUCTION: Prethrombin-1 is a Gla-domain lacking enzymatically inactive split product that results from the cleavage of fragment 1 from prothrombin by thrombin in a feedback reaction. METHODS: A prethrombin-1 preparation derived from human plasma was tested for its hemostatic and thrombogenic properties. Animal models of nail clipping (for rabbits) and tail clipping (for mice) were developed to measure blood loss in FVIII-inhibitor or rivaroxaban anticoagulated rabbits and mice, respectively. A modified Wessler test was used in rabbits to assess the thrombogenic potential by Wessler score and clot weight. Studies were performed in groups of three to six for prethrombin-1 dose escalation and comparison with prothrombin, Beriplex®, FEIBA®, and saline as a control. Data were analyzed using t-statistics or the Mann Whitney U test as applicable. RESULTS: Prethrombin-1 has excellent hemostatic properties in anticoagulated mouse and rabbit bleeding models. Wessler tests suggest that in contrast to activated and nonactivated prothrombin complexes, prethrombin-1 has negligible thrombogenic potential. CONCLUSION: The thrombin zymogen prethrombin-1 promotes hemostasis with reduced risk of thrombosis. Prethrombin-1 may have potential to become a life-saving treatment for patients who bleed or are at risk of bleeding.

New directions to develop therapies for people with hemophilia.

INTRODUCTION: The past few decades have seen a tremendous advancement in the management of hemophilia. Whether it is improved methods to attenuate critical viruses, recombinant bioengineering with decreased immunogenicity, extended half-life replacement therapies to mitigate the burden of repeated infusion treatments, novel nonreplacement products to avoid the drawback of inhibitor development with its attractive subcutaneous administration and then the introduction of gene therapy, the management has trodden a long way. AREAS COVERED: This expert review describes the progress in the treatment of hemophilia over the years. We discuss, in detail, the past and current therapies, their benefits, drawbacks, along with relevant studies leading to approval, efficacy and safety profile, ongoing trials, and future prospects. EXPERT OPINION: The technological advances in the treatment of hemophilia with convenient modes of administration and innovative modalities offer a chance for a normal existence of the patients living with this disease. However, it is imperative for clinicians to be aware of the potential adverse effects and the need for further studies to establish causality or chance association of these events with novel agents. Thus, it is crucial for clinicians to engage patients and their families in informed decision-making and tailor individual concerns and necessities.

The (human) respiratory rate at rest.

All schoolchildren know how often they breathe, but even experts don't know exactly why. The aim of this publication is to develop a model of the resting spontaneous breathing rate using physiological, physical and mathematical methods with the aid of the principle that evolution pushes physiology in a direction that is as economical as possible. The respiratory rate then follows from an equation with the parameters [Formula: see text]-production rate of the organism, resistance, static compliance and dead space of the lungs, the inspiration duration: expiration duration - ratio and the end-expiratory [Formula: see text] fraction. The derivation requires exclusively secondary school mathematics. Using the example of an adult human or a newborn child, data from the literature then result in normal values for their breathing rate at rest. The reason for the higher respiratory rate of a newborn human compared to an adult is the relatively high [Formula: see text]-production rate together with the comparatively low compliance of the lungs. A side result is the fact that the common alveolar pressure throughout the lungs and the common time constant is a consequence of the economical principle as well. Since the above parameters are not human-specific, there is no reason to assume that the above equation could not also be applicable to many animals breathing through lungs within a thorax, especially mammals. Not only physiology and biology, but also medicine, could benefit: Applicability is being discussed in pulmonary function diagnostics, including pathophysiology. However, the present publication only claims to be a theoretical concept of the spontaneous quiet breathing rate. In the absence of comparable animal data, this publication is intended to encourage further scientific tests.

Challenges in the Diagnosis and Management of Non-Severe Hemophilia.

(1) Background: Mild and moderate hemophilia, synonymous with non-severe hemophilia (NSH), are of constant interest for the clinicians. Bleeding occurs usually after trauma, injury, surgery, or inhibitor development, sometimes leading to a shift of the clinical phenotype from mild to severe, even with life-threatening and unexpected outcomes. (2) Methods: We performed a retrospective observational study conducted on 112 persons with congenital coagulopathies, 26 of them with NSH, admitted to our clinic in the period 2000 to 2022. For the diagnosis, we used laboratory studies (complete blood cell count, coagulation assays, biochemistry, thromboelastography, genetic tests) and imaging investigations (X-ray, ultrasound, CT, MRI). We selected four cases confronted with pitfalls of diagnosis and evolution in order to illustrate the sometimes provocative field of NSH. (3) Results: Confronted with challenging cases with under-, missed or delayed diagnosis and severe consequences, we aimed at presenting four such selected cases with mild or moderate hemophilia, real pitfalls in our clinical activity. (4) Conclusions: In the field of NSH, if not timely recognized, tending sometimes to remain ignored by caregivers and patients themselves, we can be confronted with challenging diagnostic situations and life-threatening bleeds.

Thromboinflammation in COVID-19: Can α2 -macroglobulin help to control the fire?

The complex COVID-19-associated coagulopathy appears to impair prognosis. Recently, we presented the hypothesis that children are to some extent protected by higher α2 -macroglobulin (α2 -M) levels from severe COVID-19. In addition to endothelial cells, thrombin, and platelets, neutrophil granulocytes also appear to play an important role. Neutrophils extrude extracellular nets, which are histone- and protease-coated web-like DNA structures; activate coagulation and platelets; and release radicals and proteases such as elastase. The unique phylogenetically ancient and "versatile" inhibitor α2 -M contributes particularly during childhood to the antithrombin activity of plasma, binds a broad spectrum of proteases, and interacts with other mediators of inflammation such as cytokines. It is suggested that the scope of basic research and clinical studies would include the potential role of α2 -M in COVID-19.

Origins, Development, Current Challenges and Future Directions with Activated Prothrombin Complex Concentrate for the Treatment of Patients with Congenital Haemophilia with Inhibitors.

Congenital haemophilia A (HA) is caused by deficiency of coagulation factor VIII (FVIII) activity, leading to spontaneous or traumatic bleeding events. While FVIII replacement therapy can treat and prevent bleeds, approximately 30% of patients with severe HA develop inhibitor antibodies that render FVIII replacement therapy ineffective. The bypassing agents (BPAs), activated prothrombin complex concentrate (aPCC) and recombinant activated FVII, first approved in 1977 and 1996, respectively, act to generate thrombin independent of pathways that involve factors IX and VIII. Both may be used in patients with congenital haemophilia and inhibitors (PwHIs) for the treatment and prevention of acute bleeds and quickly became standard of care. However, individual patients respond differently to different agents. While both agents are approved for on-demand treatment and perioperative management for patients with congenital haemophilia with inhibitors, aPCC is currently the only BPA approved worldwide for prophylaxis in PwHI. Non-factor therapies (NFTs) have a mechanism of action distinct from BPAs and have reported higher efficacy rates as prophylactic regimens. Nonetheless, treatment challenges remain with NFTs, particularly regarding the potential for synergistic action on thrombin generation with concomitant use of other haemostatic agents, such as BPAs, for the treatment of breakthrough bleeds and in perioperative management. Concomitant use of NFTs with other haemostatic agents could increase the risk of adverse events such as thromboembolic events or thrombotic microangiopathy. This review focuses on the origins, development and on-going role of aPCC in the evolving treatment landscape in the management of PwHI.

Kreuth V initiative: European consensus proposals for treatment of hemophilia using standard products, extended half-life coagulation factor concentrates and non-replacement therapies.

This report contains the updated consensus recommendations for optimal hemophilia care produced in 2019 by three Working Groups (WG) on behalf of the European Directorate for Quality of Medicines and Healthcare in the frame of the Kreuth V Initiative. WG1 recommended access to prophylaxis for all patients, the achievement of plasma factor trough levels of at least 3-5% when extended half-life factor VIII (FVIII) and FIX products are used, a personalized treatment regimen, and a choice of chromogenic assays for treatment monitoring. It was also emphasized that innovative therapies should be supervised by hemophilia comprehensive care centers. WG2 recommended mandatory collection of postmarketing data to assure the long-term safety and efficacy of new hemophilia therapies, the establishment of national patient registries including the core data recommended by the European Medicines Agency and the International Society on Thrombosis and Haemostasis, with adequate support under public control, and greater collaboration to facilitate a comprehensive data evaluation throughout Europe. WG3 discussed methodological aspects of hemophilia care in the context of access decisions, particularly for innovative therapies, and recommended that clinical studies should be designed to provide the quality of evidence needed by regulatory authorities, HTA bodies and healthcare providers. The dialogue between all stakeholders in hemophilia care and patient organizations should be fostered to implement these recommendations.

Factor VIII replacement is still the standard of care in haemophilia A.

Prophylactic factor VIII (FVIII) has dramatically improved haemophilia A treatment, preventing joint bleeding and halting the deterioration of joint status. FVIII products with an extended plasma half-life further improve patients' quality of life and increase therapeutic adherence. New licensed classes of non-replacement products include prophylactic emicizumab, which is administered subcutaneously up to every 4 weeks. However, this drug is not suitable for acute bleeding episodes or management of major surgery, and long-term data on the impact of emicizumab on joint health, FVIII inhibitor development and thrombotic risk are awaited. Prophylaxis with FVIII replacement remains the standard of care in haemophilia A, with the aim of achieving a level of haemostasis control that allows patients to meet their lifestyle goals.

Current Trend of Invasive Orthopaedic Interventions for People with Haemophilia in Romania: Single Centre Experience.

OBJECTIVE: In countries with low factor concentrate consumption, disabling joint disease remains the major morbidity in patients with haemophilia. The objective of the present analysis is to express the trend and profile of invasive orthopaedic interventions in our country with low usage of factor replacement, lacking the prophylaxis program until recent years. PATIENTS AND METHODS: This retrospective descriptive study was conducted in our university centre in Timisoara with long-lasting experience in haemophilia care, which succeeded in developing an exceptionally valuable genuine comprehensive inter-institutional cooperation. This study refers to 115 invasive interventions performed on 97 patients: 83 with haemophilia A, 10 with haemophilia B and 4 with von Willebrand disease in the period of 2001 to 2017; 17 of them had inhibitors, 5 developing inhibitors after the intervention. RESULTS AND DISCUSSION: The cohort of patients consisted mostly of young adults, aged between 7 and 49 years. The vast majority of them, 91.3% of the patients, had the burden of severe chronic arthropathy. This was the reason for 95 interventions, with programmed solution. In 20 cases the cause of invasive interventions was emergency. Knee and hip replacement represented 28% of the major interventions. The complications we encountered were excessive bleeding (12.2%), infection (13%) and inhibitor development (4.3%). CONCLUSION: Surgery is a demanding intervention in patients with haemophilia, which unfortunately cannot be ignored in our country. Hopefully, the improved availability and accessibility to replacement therapy will eliminate the necessity of these interventions, optimizing the outcomes for the next generations.

Wishes and worries of haemophilia patients. A patient survey from Bavaria.

Haemophilia care in Germany has achieved a high level and enables the majority of patients to lead a largely normal life. The Bluter Betreuung Bayern e.V. (BBB) aims to improve health care and support for haemophilia patients. A questionnaire has been developed by BBB representatives to evaluate unmet medical needs from the patient perspective. It was sent to 290 haemophilia patients and/or their parents in Bavaria in November 2015. The response rate was 51.4 %: 66 children aged < 15 years (66.7 % severe), 30 patients 15-24 years (66.7 % severe), 26 patients 25-44 years (80.8 % severe), 24 patients > 44 years (95.8 % severe). Prophylactic therapy in patients with severe haemophilia aged < 25 and ≥ 25 years is given "always" in ≥ 80 % and > 60 %, respectively. Substitution therapy is mostly uncomplicated. Satisfaction with medical care is high. Chronic pain is a problem with increasing age. Patients aged 25-44 years worry least regarding future health, safety and availability of factor products, patients > 44 years most. Overall, 80-100 % of the patients from all age groups are interested in information on the current state of science. Offers of the BBB for psychosocial support in addition to the medical care seem to be helpful and needed in all age groups.

Retromolar laryngoscopy: a randomized crossover vocal cords visualization study.

BACKGROUND: Vocal cords visualization is a major determinant for successful tracheal intubation. The aim of our study was to compare vocal cord visualization by using conventional direct laryngoscopy with retromolar direct laryngoscopy in patients with an existing retromolar gap at the right mandible. METHODS: We enrolled 100 adults needing endotracheal intubation for elective surgery. In each patient, the vocal cords were visualized and scored according to Cormack and Lehane with a Macintosh blade #3 for conventional technique and with a Miller blade #4 for the retromolar technique in a randomized sequence. Finally, tracheal intubation was performed primarily by conventional laryngoscopy and in the case of failing retromolar laryngoscopy was used as the rescue method. RESULTS: Overall 100 laryngoscopies with the conventional method and 100 laryngoscopies with the retromolar method were scored according to Cormack and Lehane. The retromolar technique achieved significant (P=0.000003) lower Cormack and Lehane scores compared to the conventional technique. In eleven patients, intubation by conventional laryngoscopy failed and seven of those patients were successfully intubated by the retromolar technique. A BURP-maneuver significantly improved vocal cord visualization during both methods. CONCLUSIONS: In summary, laryngoscopy via the retromolar method by using a Miller blade #4 lead to a significantly better vocal cord visualization compared to the conventional method performed with a Macintosh blade #3 in patients with an existing retromolar gap on the right side.

Wishes and worries of haemophilia patients.

Haemophilia care in Germany has achieved a high level and enables the majority of patients to lead a largely normal life. The Bluter Betreuung Bayern e.V. (BBB) aims to improve health care and support for haemophilia patients. A questionnaire has been developed by BBB representatives to evaluate unmet medical needs from the patient perspective. It was sent to 290 haemophilia patients and/or their parents in Bavaria in November 2015. The response rate was 51.4 %: 66 children aged < 15 years (66.7 % severe), 30 patients 15-24 years (66.7 % severe), 26 patients 25-44 years (80.8 % severe), 24 patients > 44 years (95.8 % severe). Prophylactic therapy in patients with severe haemophilia aged < 25 and ≥ 25 years is given "always" in ≥ 80 % and > 60 %, respectively. Substitution therapy is mostly uncomplicated. Satisfaction with medical care is high. Chronic pain is a problem with increasing age. Patients aged 25-44 years worry least regarding future health, safety and availability of factor products, patients > 44 years most. Overall, 80-100 % of the patients from all age groups are interested in information on the current state of science. Offers of the BBB for psychosocial support in addition to the medical care seem to be helpful and needed in all age groups.

Blood Product Supply in Germany: The Impact of Apheresis and Pooled Platelet Concentrates.

BACKGROUND: In Germany, about 60% of all produced platelet concentrates (PCs) are apheresis PCs (APCs). Ongoing discussions on APC reimbursement and costs might lead to a potential shift in pooled PC (PPC)/APC production. Objective of this analysis was to build a comprehensive model from the societal perspective to evaluate consequences associated with shifts in platelet supply and demand. METHODS: Literature search, desktop researches on platelet supply and demand. Model calculations, time horizon one year: model input from the Paul-Ehrlich-Institute, data 2013. Base case: 19.2% of annual whole blood donations (WBDs) were used for production of 38.5% PPCs, decay of 46,218 PCs (8.0%). Scenarios calculated: variation in PPC proportion of 10-100%. RESULTS: Base case: during PPC production 41,957-83,913 red blood cell concentrates (RBCCs) are estimated to be lost, which corresponds to 1-2% of annual RBCCs in Germany. Scenarios were calculated for a production of 60-100% PPCs: loss is estimated to be 1.5-5.0% of annual RBCCs (65,430-218,099), decay 54,189-69,022 PCs (9.4-12.0%). CONCLUSION: Production of different blood components is interlinked and sensitive to unidimensional decisions. Increasing PPC proportion has negative impact on the RBCC production and on the antigen-matched APC donor pool. Completion of the model calculations to predict the optimal PPC/APC proportion would require evidence on the number of refractory patients, donor pool sizes, and incidences of diseases requiring platelet transfusions.