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Pyruvate kinase (PK) is a key enzyme involved in the final step of glycolysis, essential to produce adenosine triphosphate (ATP). Relatively decreased red blood cell (RBC) PK activity (reflected by a lower PK/hexokinase [HK] ratio) and PK thermostability (PK activity after exposure to heat) were recently identified as pathophysiological features of sickle cell disease (SCD). In this study, we investigated whether impaired PK function is associated with sickle RBC properties and SCD-related clinical manifestations. This study included 97 non-transfused patients with SCD (88 HbSS, 9 HbS/β0 thalassemia). PK thermostability was correlated with RBC parameters such as reticulocyte count (r = -0.402, p < 0.0001) and hemoglobin F (r = 0.394, p < 0.0001), and indicators of impaired functional properties of sickle RBCs, such as the point of sickling (r = -0.417, p < 0.0001), oxygen affinity (r = 0.408, p < 0.001) and RBC adhesion to laminin (r = -0.322, p = 0.024). Additionally, a low PK/HK ratio correlated with decreased PK thermostability (r = 0.308, p = 0.002), decreased RBC deformability (r = 0.268, p = 0.009), and elevated 2,3-diphosphoglycerate levels (r = -0.244, p = 0.016). Multivariate Poisson regression analysis demonstrated that reduced PK thermostability and PK/HK ratio were associated with a higher incidence of SCD-related clinical complications. For every 10-unit decrease in PK thermostability and 1-unit decrease in PK/HK ratio, the incidence of SCD-related clinical complications increased by 11% (p = 0.012) and 10% (p = 0.019), respectively. Altogether, these findings indicate that impaired PK function is related to compromised sickle RBC properties and SCD-related clinical manifestations. This supports the relevance and underlines the potential of PK activation therapy., (© 2025 The Author(s). American Journal of Hematology published by Wiley Periodicals LLC.)

Mitapivat is an investigational, oral, small-molecule allosteric activator of pyruvate kinase (PK). PK is a regulatory glycolytic enzyme that is key in providing the red blood cell (RBC) with sufficient amounts of adenosine triphosphate (ATP). In sickle cell disease (SCD), decreased 2,3-DPG levels increase the oxygen affinity of hemoglobin, thereby preventing deoxygenation and polymerization of sickle hemoglobin. The PK activator mitapivat has been shown to decrease levels of 2,3-DPG and increase levels of ATP in RBCs in patients with SCD. In this phase 2, investigator-initiated, open-label study (https://www.clinicaltrialsregister.eu/ NL8517; EudraCT 2019-003438-18), untargeted metabolomics was used to explore the overall metabolic effects of 8-week treatment with mitapivat in the dose-finding period. In total, 1773 unique metabolites were identified in dried blood spots of whole blood from ten patients with SCD and 42 healthy controls (HCs). The metabolic phenotype of patients with SCD revealed alterations in 139/1773 (7.8%) metabolites at baseline when compared to HCs (false discovery rate-adjusted p  < 0.05), including increases of (derivatives of) polyamines, purines, and acyl carnitines. Eight-week treatment with mitapivat in nine patients with SCD altered 85/1773 (4.8%) of the total metabolites and 18/139 (12.9%) of the previously identified altered metabolites in SCD (unadjusted p  < 0.05). Effects were observed on a broad spectrum of metabolites and were not limited to glycolytic intermediates. Our results show the relevance of metabolic profiling in SCD, not only to unravel potential pathophysiological pathways and biomarkers in multisystem diseases but also to determine the effect of treatment., Competing Interests: Minke A. E. Rab and Richard van Wijk received research funding from Axcella Health Inc. and Pfizer. Eduard J. van Beers and Richard van Wijk are consultants for Pfizer. Minke A. E. Rab, Eduard J. van Beers, and Richard van Wijk received research funding and are consultants for Agios Pharmaceuticals Inc. M.H.C's institution has received investigator‐initiated research and travel grants as well as speaker fees over the years from the Netherlands Organisation for Scientific Research (NWO) and Netherlands National Research Agenda (NWA), the Netherlands Organization for Health Research and Development (ZonMw), the Dutch Innovatiefonds Zorgverzekeraars, Baxter/Baxalta/Shire/Takeda, Pfizer, Bayer Schering Pharma, CSL Behring, Sobi Biogen, Novo Nordisk, Novartis, and Nordic Pharma, and for serving as a steering board member for Roche, Bayer, and Novartis for which fees go to the Erasmus MC as an institution. Erfan Nur receives research funding from Novartis and Emmaus and participates in the advisory board of Novartis. Bart J. Biemond received research funding from Sanquin, Global Blood Therapeutics/Pfizer, and Novartis and participated in advisory boards of Novartis, Bristol‐Myers Squibb/Celgene, Global Blood Therapeutics/Pfizer, Novo Nordisk, and CSL Behring. The remaining authors declare no competing financial interests., (© 2024 The Author(s). HemaSphere published by John Wiley & Sons Ltd on behalf of European Hematology Association.)

The most common forms of sickle cell disease (SCD) are sickle cell anemia (SCA; HbSS) and HbSC disease. In both, especially the more dense, dehydrated and adherent red blood cells (RBCs) with reduced deformability are prone to hemolysis and sickling, and thereby vaso-occlusion. Based on plasma amino acid profiling in SCD, a composition of 10 amino acids and derivatives (RCitNacQCarLKHVS; Axcella Therapeutics, USA), referred to as endogenous metabolic modulators (EMMs), was designed to target RBC metabolism. The effects of ex vivo treatment with the EMM composition on different RBC properties were studied in SCD ( n  = 9 SCA, n  = 5 HbSC disease). Dose-dependent improvements were observed in RBC hydration assessed by hemocytometry (MCV, MCHC, dense RBCs) and osmotic gradient ektacytometry (Ohyper). Median (interquartile range [IQR]) increase in Ohyper compared to vehicle was 4.9% (4.0%-5.5%), 7.5% (6.9%-9.4%), and 12.8% (11.5%-14.0%) with increasing 20×, 40×, and 80X concentrations, respectively (all p  < 0.0001). RBC deformability (EImax using oxygen gradient ektacytometry) increased by 8.1% (2.2%-12.1%; p  = 0.0012), 9.6% (2.9%-15.1%; p  = 0.0013), and 13.3% (5.7%-25.5%; p  = 0.0007), respectively. Besides, RBC adhesion to subendothelial laminin decreased by 43% (6%-68%; p  = 0.4324), 58% (48%-72%; p  = 0.0185), and 71% (49%-82%; p  = 0.0016), respectively. Together, these results provide a rationale for further studies with the EMM composition targeting multiple RBC properties in SCD., Competing Interests: R.v.W. and M.R. received research funding from Axcella Therapeutics and Pfizer. E.v.B. and R.v.W. are consultants for Pfizer. E.v.B., R.v.W., and M.R. receive research funding and are consultants for Agios Pharmaceuticals Inc. M.J.K. and R.W. are employees of Axcella Therapeutics. The remaining authors declare no competing financial interests., (© 2024 The Authors. eJHaem published by British Society for Haematology and John Wiley & Sons Ltd.)

Targeting the primary pathogenic event of sickle cell disease (SCD), the polymerization of sickle hemoglobin (HbS), may prevent downstream clinical events. Mitapivat, an oral pyruvate kinase (PK) activator, has therapeutic potential by increasing adenosine triphosphate (ATP) and decreasing 2,3-diphosphoglycerate (2,3-DPG), a glycolytic red blood cell (RBC) intermediate. In the previously reported 8-week dose-finding period of this phase 2, investigator-initiated, open-label study, mitapivat was well tolerated and showed efficacy in SCD. Here, the 1-year fixed-dose extension period is reported in which 9 of 10 included patients (90%) aged ≥16 years with SCD (HbSS, HbS/β0, or HbS/β+) continued with mitapivat. Mostly mild treatment-emergent adverse events (AEs) (most commonly, transaminase increase and headache) were still reported. Apart from the reported nontreatment-related serious AE (SAE) of a urinary tract infection in the dose-finding period, 1 nontreatment-related SAE occurred in the fixed-dose extension period in a patient who died of massive pulmonary embolism due to COVID-19. Importantly, sustained improvement in Hb level (mean increase, 1.1 ± 0.7 g/dL; P = .0014) was seen, which was accompanied by decreases in markers of hemolysis. In addition, the annualized rate of vaso-occlusive events reduced significantly from a historic baseline of 1.33 ± 1.32 to 0.64 ± 0.87 (P = .0489) when combining the dose-finding period and fixed-dose extension period. Cellularly, the ATP:2,3-DPG ratio and Hb-oxygen affinity significantly increased and RBC sickling (point of sickling) nonsignificantly reduced. Overall, this study demonstrated 1-year safety and efficacy of treatment with mitapivat in SCD, supporting further evaluation in ongoing phase 2/3 study (RISE UP, NCT05031780). This trial was registered at https://www.clinicaltrialsregister.eu/ as NL8517 and EudraCT 2019-003438-18., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Adenosine Triphosphatase (ATPase) Phospholipid Transporting 11C gene (ATP11C) encodes the major phosphatidylserine (PS) flippase in human red blood cells (RBCs). Flippases actively transport phospholipids (e.g., PS) from the outer to the inner leaflet to establish and maintain phospholipid asymmetry of the lipid bilayer of cell membranes. This asymmetry is crucial for survival since externalized PS triggers phagocytosis by splenic macrophages. Here we report on pathophysiological consequences of decreased flippase activity, prompted by a patient with hemolytic anemia and hemizygosity for a novel c.2365C > T p.(Leu789Phe) missense variant in ATP11C. ATP11C protein expression was strongly reduced by 58% in patient-derived RBC ghosts. Furthermore, functional characterization showed only 26% PS flippase activity. These results were confirmed by recombinant mutant ATP11C protein expression in HEK293T cells, which was decreased to 27% compared to wild type, whereas PS-stimulated ATPase activity was decreased by 57%. Patient RBCs showed a mild increase in PS surface exposure when compared to control RBCs, which further increased in the most dense RBCs after RBC storage stress. The increase in PS was not due to higher global membrane content of PS or other phospholipids. In contrast, membrane lipid lateral distribution showed increased abundance of cholesterol-enriched domains in RBC low curvature areas. Finally, more dense RBCs and subtle changes in RBC morphology under flow hint toward alterations in flow behavior of ATP11C-deficient RBCs. Altogether, ATP11C deficiency is the likely cause of hemolytic anemia in our patient, thereby underlining the physiological role and relevance of this flippase in human RBCs., (© 2023 The Authors. American Journal of Hematology published by Wiley Periodicals LLC.)

Novel developments in therapies for various hereditary hemolytic anemias reflect the pivotal role of pyruvate kinase (PK), a key enzyme of glycolysis, in red blood cell (RBC) health. Without PK catalyzing one of the final steps of the Embden-Meyerhof pathway, there is no net yield of adenosine triphosphate (ATP) during glycolysis, the sole source of energy production required for proper RBC function and survival. In hereditary hemolytic anemias, RBC health is compromised and therefore lifespan is shortened. Although our knowledge on glycolysis in general and PK function in particular is solid, recent advances in genetic, molecular, biochemical, and metabolic aspects of hereditary anemias have improved our understanding of these diseases. These advances provide a rationale for targeting PK as therapeutic option in hereditary hemolytic anemias other than PK deficiency. This review summarizes the knowledge, rationale, (pre)clinical trials, and future advances of PK activators for this important group of rare diseases., Competing Interests: Declaration of Competing Interest M.v.D., J.d.W., K.K., A.G., M.R., E.v.B. and R.v.W. receive research funding from Agios Pharmaceuticals Inc. K.K., E.v.B. and R.v.W. are consultants for Agios Pharmaceuticals Inc. K.K., M.R. and R.v.W. receive research funding from Pfizer. K.K. and R.v.W. are consultants for Pfizer. K.K. is also consultant for Alexion Pharmaceuticals, Celgene/Bristol Myers Squibb, Forma Therapeutics, Novo Nordisk, and chair of the Data Safety Monitoring Board for Bioverativ/Sanofi and Sangamo. A.G. receives research funding from Bristol Myers Squibb, Saniona and Sanofi and has done consulting for Agios, Bluebird Bio, Bristol Myers Squibb, Novartis, Novo Nordisk, Pharmacosmos. M.R. and R.v.W. receive research funding from Axcella Health Inc. The remaining author declares no conflict of interest., (Crown Copyright © 2023. Published by Elsevier Ltd. All rights reserved.)

Erythrocytosis is associated with increased red blood cell mass and can be either congenital or acquired. Congenital secondary causes are rare and include germline variants increasing haemoglobin (Hb)-oxygen affinity (e.g., Hb or bisphosphoglycerate mutase (BPGM) variants) or affecting oxygen-sensing pathway proteins. Here, we describe five adults from three kindreds with erythrocytosis associated with heterozygosity for BPGM variants, including one novel. Functional analyses showed partial BPGM deficiency, reduced 2,3-bisphosphoglycerate levels and/or increased Hb-oxygen affinity. We also review currently known BPGM variants. This study contributes to raising awareness of BPGM variants, and in particular that heterozygosity for BPGM deficiency may already manifest clinically., (© 2022 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Aim: To explore the feasibility of the Post-Stroke Depression toolkit in terms of fidelity and acceptability in daily nursing practice., Background: Depression after stroke is common and influences patients' recovery significantly. Although stroke guidelines recommend early depression screening and treatment, depressive symptoms remain unrecognized. To enhance adoption of evidence into the context of the daily practice of stroke treatment, we developed the Post-Stroke Depression toolkit, an evidence-based nurse-led intervention for the early management of depressive symptoms after a stroke for use in the hospital setting., Design: An explanatory mixed-methods before-and-after study design., Methods: Data were collected continuously from March 2012 - June 2013 during three phases: pre-implementation, the implementation phase (where implementation strategies guided the implementation) and the sustainability phase (executed without the implementation strategies) and involved patient chart audits and surveys and individual and focus group interviews with nurses., Results: A total of 775 patient charts were audited to examine fidelity. Implementation of the Post-Stroke Depression toolkit during the implementation phase resulted in an increase in depression screening (+72.9%) and more patients receiving nursing interventions (+11.1%). During the sustainability phase, screening for depression decreased (-16.3%), while the application of the nursing interventions remained unchanged (+0.6%). The acceptability of the toolkit was judged to be good., Conclusions: The Post-Stroke Depression toolkit was found to be feasible in terms of fidelity and acceptability, improving structural screening for depressive symptoms as well as the application of nursing interventions in case of a positive screening., Trial Registration: ClinicalTrials.gov Identifier: NCT03500250., (© 2018 The Authors. Journal of Advanced Nursing Published by John Wiley & Sons Ltd.)

The early detection of depression after stroke is essential for the optimization of recovery in aphasic stroke patients. The purpose of this study was to evaluate the psychometric properties of the Signs of Depression Scale (SODS), a non-language-based screening instrument. We conducted a cross-sectional study in a sample of 58 stroke patients in a rehabilitation center. The internal consistency and interrater reliability were good (α = .71 and intraclass correlation coefficient [ICC] = .79). The pre-defined hypotheses confirmed the construct validity, and the correlation between the SODS and the Patient Health Questionnaire-9 (PHQ-9) was moderate ( r b = .32). At a cutoff score of ≥1, the sensitivity was 0.80, and the specificity was 0.39. These findings indicate that the SODS is appropriate to screen for depressive symptoms and can be used by nurses to identify symptoms of depression in patients with aphasia who require further assessment.

Objectives: To investigate (1) the diagnostic value of the Signs of Depression Scale (SODS) in a Likert scale format and (2) whether the Likert scale improves the diagnostic value compared with the original dichotomous scale., Design: Cross-sectional multicentre study., Setting: One general and one university hospital in the Netherlands., Subjects: A total of 116 consecutive hospitalized stroke patients, of whom 53 were patients with communicative impairment., Main Measures: Depression was diagnosed with the Composite International Diagnostic Interview (CIDI) administered to the patients' relatives. The Barthel Index (BI) was used as an external validator., Results: The correlation between the CIDI and the SODS-Likert or the SODS was small ( r b  = 0.18), and the correlation between the Barthel Index and the SODS-Likert ( r s  = -0.30) or the SODS ( r s  = -0.33) was moderate. For both instruments, the discriminatory power for diagnosing depression when compared with the CIDI was best at a cut-off score of ⩾2. The internal consistency of the SODS-Likert was acceptable (α = 0.69) and slightly higher than that of the SODS (α = 0.57). The inter-rater reliability of the SODS-Likert and the SODS was acceptable (intraclass correlation coefficient (ICC) 0.66 and ICC 0.80, respectively). The clinical utility was rated good., Conclusion: The diagnostic value of the SODS did not improve using a Likert scale format. However, the diagnostic value of the original dichotomous SODS is reasonable for the initial mood assessment of stroke patients with communicative impairment.

Purpose: As a first step to formulate a practical definition for movement quality (MQ), this study aims to explore how Dutch allied health care professionals (AHCPs) describe MQ of daily life activities in patients with low back pain (LBP)., Methods: In this qualitative cross-sectional digital survey study, Dutch AHCPs (n = 91) described MQ in open text (n = 91) and with three keywords (n = 90). After exploratory qualitative content analysis, the ICF linking rules (International Classification of Functioning, Disability and Health) were applied to classify MQ descriptions and keywords., Findings: The identified meaningful concepts (MCs) of the descriptions (274) and keywords (239) were linked to ICF codes (87.5% and 80.3%, respectively), Personal factors (5.8% and 5.9%, respectively), and supplementary codes (6.6% and 13.8%, respectively). The MCs were linked to a total of 31 ICF codes, especially to b760 'control of voluntary movement functions', b7602 'coordination of voluntary movements', d4 'Mobility', and d230 'carry out daily routine'. Negative and positive formulated descriptions elucidated different MQ interpretations., Conclusions: Descriptions of MQ given by Dutch AHCPs in patients with LBP cover all ICF components. Coordination and functional movements are seen as the most elementary concepts of MQ. Variation in MQ descriptions and interpretations hinders defining MQ and indicates the necessity of additional steps.

Objective: To identify and critically appraise the evidence for instruments assessing depression in stroke patients with aphasia., Methods: The PubMed, CINAHL, Web of Science, Psych Info and Cochrane databases were searched from inception until May 2015., Results: Of the 383 titles found in the search, 15 articles met the inclusion criteria and six instruments were identified: The Aphasic Depression Rating Scale, the Clinical Global Impression-Scale, the Stroke Aphasic Depression Questionnaire (four versions), the Signs of Depression Scale, the Visual Analogue Mood Scale (three versions) and the Visual Analogue Self Esteem Scale. Supporting evidence for reliability and validity was limited owing to methodological flaws in the studies influencing the ratings of methodological quality. Feasibility data were available for all instruments. Rating time of the instruments ranged from less than one minute to five minutes, two instruments required extensive training., Conclusion: A number of instruments to assess depressive symptoms in patients with aphasia are available. None of the instruments however, were found to be sufficiently investigated and most of the studies identified were of low methodological quality. Given the present evidence, the Stroke Aphasic Depression Questionnaire-10, the Stroke Aphasic Depression Questionnaire-H10 and the Signs of Depression Scale are the most feasible and can be recommended for clinical practice., (© The Author(s) 2015.)

Purpose: To calculate the sensitivity and specificity of computed tomographic (CT) angiography in the diagnosis of cerebral aneurysms in patients with acute subarachnoid hemorrhage (SAH) at presentation., Materials and Methods: A systematic search for relevant studies was performed of the PubMed/MEDLINE and EMBASE databases. Two reviewers independently assessed the methodologic quality of each study by using the Quality Assessment of Diagnostic Accuracy Studies tool. The inclusion criteria were met by 50 studies. Heterogeneity was tested, and the presence of publication bias was visually assessed (by using a funnel plot). A meta-analysis of the reported sensitivity and specificity of each study with 95% confidence intervals (CIs) was performed on a per-patient level., Results: Concerning sensitivity, the selected studies showed moderate heterogeneity. For specificity, low heterogeneity was observed. Moderate-heterogeneity studies that investigated only sensitivity or specificity were excluded from the pooled analyses by using a bivariate random effects model. The majority of the studies (n = 30) used a four-detector row CT scanner. The studies had good methodologic quality. Pooled sensitivity was 98% (95% CI: 97%, 99%), and pooled specificity was 100% (95% CI: 97%, 100%). Potential sources of variability among the studies were variations in the methodologic features (quality score), CT examination procedure (number of rows on the multidetector CT scanner), the standard of reference used, and the prevalence of ruptured intracranial aneurysms. There was evidence for publication bias, which may have led to overestimation of the diagnostic accuracy of CT angiography., Conclusion: Multidetector CT angiography can be used as a primary examination tool in the diagnostic work-up of patients with SAH.

Background: The increased threat of nuclear, biological and chemical (NBC) weapons underlines the need of protective clothing and gas masks, but this may impair performance. Thus, attention should be focused on the nutritional requirements., Hypothesis: Optimal performance is guaranteed if the supply of water and energy is adequate., Methods: Two groups of 20 trained military men (mean age 22 yr) received either an isotonic carbohydrate drink or a placebo drink (flavored water) for 24 h under simulated NBC conditions (wearing gas masks and protective clothing). Various physical and mental tests were performed at intervals and blood samples were collected three times., Results: Five men of the placebo group had to be withdrawn during the experiment because of exhaustion. The decrease in physical performance (about 15%) and mental performance (about 20%) was most apparent for the group that had only water for consumption., Conclusions: When only water is consumed, physical performance of a group of military men decreases during 24 h of simulated NBC conditions. An isotonic carbohydrate drink is recommended with respect to maintaining performance under NBC conditions. Energy restriction prior to an NBC scenario has a negative influence on performance.

Objective: Comparison of diabetes regulation by strict or less strict observance of the relevant standard protocol of the Netherlands College of General Practitioners (NHG standard)., Setting: Two general practices in the region 'Nieuwe Waterweg Noord', near Rotterdam, the Netherlands., Design: Cross-sectional comparative descriptive study., Method: Type II diabetic patients from two general practices were investigated for diabetic symptoms, type of medication, metabolic abnormalities and (risk factors for) complications in relation to their HbA1c as a measure of mean blood glucose regulation. One GP strictly observed the NHG standard as a protocol, the other GP used it as a guideline., Results: Metabolic control was significantly better in the 'strictly observing' general practice than in the 'guideline' practice: HbA1c 7.3% (SD: 1.7) versus 8.1% (1.5) (p < 0.01). Systolic blood pressure was also significantly lower in the 'strict' practice: 141 mmHg (23) versus 155 mmHg (21) (p < 0.01), but mean age was lower and mean duration of diabetes was significantly shorter. The prevalence of macrovascular complications, diabetic retinopathy and nephropathy did not differ significantly in these practices; symptoms of polyneuropathy, however, were found more often in the patients of the 'strict' practice (41% versus 20%; p < 0.05)., Conclusion: Good metabolic control in patients with type II diabetes mellitus is made possible by strict application of the NHG standard for general practitioners.