Romy Kronstein-Wiedemann

Lipoprotein apheresis is a highly effective and well-established extracorporeal therapy designed to remove lipoproteins from human circulation on a large scale, particularly in patients with progressive cardiovascular diseases when conventional treatments fail to achieve adequate lipoprotein reduction. Beyond its lipid-lowering capabilities, therapeutic apheresis is used to eliminate pathogenic substances, such as autoantibodies and immune complexes, and to exert immunomodulatory effects. Recent research highlights its potential to reduce inflammatory mediators, making it a promising intervention for conditions associated with systemic inflammation, including neurodegenerative diseases and post-infectious syndromes. In addition to its established applications, therapeutic apheresis is being explored as a novel approach to address emerging environmental health challenges, such as the accumulation of per- and polyfluoroalkyl substances (PFAS) and micro- and nanoplastics (MNPs) in living organisms. These pollutants, which are increasingly pervasive in the environment, pose significant health risks, including metabolic disruption, carcinogenesis, and neuroinflammation. Recognizing the urgency of this issue, institutions such as the US Department of Health and Human Services have initiated research programs to develop methods to monitor and remove these contaminants from the human body. Here, our preliminary findings suggest that therapeutic apheresis may represent a promising approach for reducing environmental toxins, alongside its established role in lowering lipoproteins and inflammatory biomarkers, and warrants further systematic clinical investigation. This is based on the hypothesis that PFAS and MNPs form aggregates with lipids and proteins, suggesting that therapeutic apheresis could be an ideal method for clearance. In the initial results, we observed decreases in both PFAS and MNP levels in patient blood and sequestered plasma following double filtration plasmapheresis, although responses varied across individuals and analytes. Tissue and in vitro studies using imaging and functional bioassays may be suitable for demonstrating the potential of apheresis to remove PFAS and MNPs, as well as for assessing the impact of MNPs on cell viability, inflammation, and secretome profiles. These findings could serve as clinical surrogates to guide treatment frequency and evaluate the sustainability of therapeutic apheresis in mitigating health risks associated with environmental pollutants. While larger, well-designed clinical trials are needed to confirm these benefits, these early results could lay the groundwork for future research and clinical applications.

In vitro red blood cell (RBC) production offers a promising complement to conventional blood donation, particularly for patients with rare blood types. Previously, we developed imBMEP-A, the first erythroid cell line derived from reticulocyte progenitors, which maintains robust hemoglobin expression and erythroid differentiation in the presence of erythropoietin (EPO) despite its immortalized state. However, clinical translation remains hindered by the inability to scale up production due to impaired in vitro enucleation of RBC progenitor cell lines. Enhancing enucleation efficiency in imBMEP-A cells involved CRISPR/Cas9-mediated knockout (K.O.) of miR-30a-5p, a key enucleation inhibitor, moderately increasing rates to 3.3 ± 0.4%– 8.9 ± 1.7%. Further investigation of enucleation inefficiencies led to transcriptome and proteome comparisons between imBMEP-miR30a-K.O. cells and hematopoietic stem cells (HSCs). These analyses revealed altered gene expression and protein abundances linked to metabolic transitions, apoptosis promotion, and cytoskeletal regulation. Notably, forced expression of the proto-oncogene c-Myc, required for cell immortalization, emerged as a key driver of these physiological changes. Counteracting these effects required optimization of imBMEP-A cells by activating BCL-XL transcription and knocking out SCIN, which encodes the actin-severing protein scinderin. While BCL-XL is upregulated in normal erythropoiesis, it is downregulated in imBMEP-A. Conversely, SCIN, typically absent in erythroid cells, is highly expressed in imBMEP-A, disrupting actin organization. These interventions improved viability, restored actin network formation, and increased terminal erythropoiesis, yielding 22.1 ± 1.7% more orthochromatic erythroblasts. These findings establish a foundation for optimizing imBMEP-A cells for therapeutic use and advancing the understanding the pathophysiology of erythroleukemia. Graphical Abstract

Introduction: 1-5% of all patients with COVID-19, a disease caused by infection with Severe Acute Respiratory Syndrome Virus 2 (SARS-Cov-2), even those with mild COVID-19 symptoms, continue to have symptoms after initial recovery. Symptoms associated with the post-acute sequelae of COVID-19 (PACS) include, among others, fatigue, shortness of breath, cough, and cognitive dysfunction. Since the dysregulated immune response appears to be caused by the sustained activation of certain immune cells, including monocytes, and the release of specific cytokines, the aim of our study was to investigate the effect of PACS disease on monocyte subpopulations.Methods: Twenty-two healthy and thirty-two patients with PACS were included into this study. We performed blood gas analysis and measured hematological parameters from peripheral blood of PACS patients and compared them with healthy donors. Surface markers to identify monocyte subpopulations were analyzed by flow cytometry.Results: PACS patients had higher numbers of intermediate and CD56+ monocytes, whereas the numbers of total monocytes, classical and non-classical monocytes were normal compared to healthy donors. Comparison of patients with and without fatigue, cough, and dyspnea showed no difference in monocyte subset frequencies. However, patients with cognitive dysfunction had increased numbers of non-classical monocytes compared to patients without this symptom.Discussion: This suggests a disturbed homeostasis of the monocyte subsets in the peripheral blood of patients with PACS.

In recent years, Raman spectroscopy has garnered growing interest in the field of biomedical research. It offers a non-invasive and label-free approach to defining the molecular fingerprint of immune cells. We utilized Raman spectroscopy on optically trapped immune cells to investigate their molecular compositions. While numerous immune cell types have been studied in the past, the characterization of living human CD3/CD28-stimulated T cell subsets remains incomplete. In this study, we demonstrate the capability of Raman spectroscopy to readily distinguish between naïve and stimulated CD4 and CD8 cells. Additionally, we compared these cells with monocytes and discovered remarkable similarities between stimulated T cells and monocytes. This paper contributes to expanding our knowledge of Raman spectroscopy of immune cells and serves as a launching point for future clinical applications.

Background: MicroRNAs (miRNAs) are small, endogenous non-coding RNA molecules that inhibit gene expression through either destabilization of the target mRNA or translational repression. MiRNAs recognize target sites, most commonly found in the 3′-untranslated regions of cognate mRNAs. This review aims to provide a state-of-the-art overview of the role of miRNAs in the regulation of major blood group antigens such as ABH as well as cancer-specific glycans. Summary: Besides their known roles in the control of developmental processes, proliferation, apoptosis, and carcinogenesis, miRNAs have recently been identified to play a regulatory role during erythropoiesis and blood group antigen expression. Since only little is known about the function of the red cell membrane proteins carrying blood group antigens, it is of great interest to shed light on the regulatory mechanisms of blood group gene expression. Some carrier proteins of blood group antigens are not restricted to red blood cells and are widely expressed in other bodily fluids and tissues and quite a few play a crucial role in tumor cells, as either tumor suppressors or promoters. Key Message: All available data point at a tremendous physiological as well as pathophysiological relevance of miRNAs in context of blood group regulation. Furthermore, miRNAs are involved in the regulation of pleiotropic genetic pathways such as hematopoiesis and tumorigenesis and thus have to be studied in future research on this subject.

COVID-19 disease, caused by the severe acute respiratory syndrome virus 2 (SARS-CoV-2), induces a broad spectrum of clinical symptoms ranging from asymptomatic cases to fatal outcomes. About 10–35% of all COVID-19 patients, even those with mild COVID-19 symptoms, continue to show symptoms, i. e., fatigue, shortness of breath, cough, and cognitive dysfunction, after initial recovery. Previously, we and others identified red blood cell precursors as a direct target of SARS-CoV-2 and suggested that SARS-CoV-2 induces dysregulation in hemoglobin- and iron-metabolism contributing to the severe systemic course of COVID-19. Here, we put particular emphasis on differences in parameters of clinical blood gas analysis and hematological parameters of more than 20 healthy and Long-COVID patients, respectively. Long-COVID patients showed impaired oxygen binding to hemoglobin with concomitant increase in carbon monoxide binding. Hand in hand with decreased plasma iron concentration and transferrin saturation, mean corpuscular hemoglobin was elevated in Long-COVID patients compared to healthy donors suggesting a potential compensatory mechanism. Although blood pH was within the physiological range in both groups, base excess- and bicarbonate values were significantly lower in Long-COVID patients. Furthermore, Long-COVID patients displayed reduced lymphocyte levels. The clinical relevance of these findings, e. g., as a cause of chronic immunodeficiency, remains to be investigated in future studies. In conclusion, our data suggest impaired erythrocyte functionality in Long-COVID patients, leading to diminished oxygen supply. This in turn could be an explanation for the CFS, dyspnea and anemia. Further investigations are necessary to identify the underlying pathomechanisms.

The ABO blood group (BG) system is of great importance for blood transfusion and organ transplantation. Since the same transcription factors (TFs) and microRNAs (miRNAs) govern the expression of ABO BG antigens and regulate erythropoiesis, we hypothesized functional connections between both processes. We found significantly higher hemoglobin and hematocrit values in BG B blood donors compared to BG A. Furthermore, we observed that erythropoiesis in BG B hematopoietic stem/progenitor cells (HSPCs) was accelerated compared to BG A HSPCs. Specifically, BG B HSPCs yielded more lineage-specific progenitors in a shorter time (B: 31.3 ± 2.2% vs. A: 22.5 ± 3.0%). Moreover, non-BG A individuals exhibited more terminally differentiated RBCs with higher enucleation rates containing more hemoglobin compared to BG A. Additionally, we detected increased levels of miRNA-215-5p and -182-5p and decreased expression of their target TFs RUNX1 and HES-1 mRNAs in erythroid BG B precursor cells compared to BG A. This highlights the important roles of these factors for the disappearance of differentiation-specific glycan antigens and the appearance of cancer-specific glycan antigens. Our work contributes to a deeper understanding of erythropoiesis gene regulatory networks and identifies its interference with BG-specific gene expression regulations particularly in diseases, where ABO BGs determine treatment susceptibility and disease progression.

Die Bluttransfusion ist ein wesentlicher und unersetzlicher Teil der modernen Medizin. Jedoch stellt vor allem bei Patienten mit sehr seltenen Blutgruppenkonstellationen der Mangel an Blutprodukten auch heute noch ein wichtiges Gesundheitsproblem weltweit dar. Um diesem Problem entgegenzutreten, versucht man seit einiger Zeit künstlich rote Blutzellen zu generieren. Diese haben potenzielle Vorteile gegenüber Spenderblut, wie z. B. ein verringertes Risiko für die Übertragung von Infektionskrankheiten. Diese Übersicht fasst die aktuellen Entwicklungen über den Prozess der Erythropoese, die Expansionsstrategien der erythrozytären Zellen, der verschiedenen Quellen für ex vivo expandierte Erythrozyten, die Hürden für die klinische Anwendung und die zukünftigen Möglichkeiten der Anwendung zusammen. Blood transfusion is an essential and irreplaceable part of modern medicine. However, particularly in patients with very rare blood groups, the lack of blood products still represents an important health problem worldwide. To address this problem, the focus of research in more recent years has been shifting to the generation of artificial red blood cells. These have potential advantages over donated blood, such as a reduced risk of transmitting infectious diseases. This overview summarises the current state of research on the process of erythropoiesis, the expansion strategies of the erythrocyte cells, the various sources of ex vivo expanded erythrocytes, the hurdles for clinical application, and the prospective scope in therapeutic administration. Publication Date: 27 August 2021 (online) © 2021. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany