Investigating the relationship between FRailty And Quality of LIfe in patients with heart faiLure and CKD (FRAIL study).

AIMS: Patients with chronic kidney disease (CKD) or heart failure (HF) are disproportionally affected by frailty, an independent predictor of morbidity. The prevalence of frailty and its impact on quality of life (QoL) in a unique population of patients with both CKD and HF (CKD-HF) is unclear. The aim of this study was to investigate the association between frailty and QoL in patients with CKD-HF. METHODS AND RESULTS: Patients were identified from a tertiary care cardiorenal clinic. Eligible patients had CKD-HF with a stable estimated glomerular filtration rate of <60 mL/min/1.732. Data were collected from each participant at one point in time using surveys delivered by study personnel between 14 July 2022 and 31 March 2023. Frailty was defined as Modified Frailty Phenotype (MFP) score ≥3. The Medical Outcomes Study 36-item Short Form Health Survey (SF-36) was used to assess QoL. Demographic data were retrospectively collected from electronic patient records. Demographics and QoL were compared between frail and non-frail cohorts using Pearson's R and Student's t-test (two-tailed, alpha-priori = 0.05). One hundred five participants consented, and 103 completed the questionnaires in full. Amongst the 103 participants, 49.5% (n = 51) were frail. Frailty was related to sex (P = 0.021) and medication count (P = 0.007), however not to other clinical measures, including estimated glomerular filtration rate (P = 0.437) and ejection fraction (P = 0.911). Frail patients reported poorer QoL across physical functioning (P < 0.001), general health (P < 0.001), bodily pain (P = 0.004), social functioning (P < 0.001), and energy levels (P < 0.001), however not emotional wellbeing (P = 0.058); 51.5% cited 'better quality of life' as their healthcare priority, over longer survival (23.3%) or avoiding hospital admissions (22.3%). This was consistent across frail and non-frail groups. CONCLUSIONS: A large proportion of CKD-HF patients are frail, regardless of disease severity, and more susceptible to significantly poorer QoL across physical and social domains. Improving QoL is the priority of patients across both frail and non-frail cohorts, further emphasizing the need for prompt recognition of frailty as well as possible intervention and prevention.

Combining long-term circuit mapping and network transcriptomics with SiR-N2c.

An exciting frontier in circuit neuroscience lies at the intersection between neural network mapping and single-cell genomics. Monosynaptic rabies viruses provide a promising platform for the merger of circuit mapping methods with -omics approaches. However, three key limitations have hindered the extraction of physiologically meaningful gene expression profiles from rabies-mapped circuits: inherent viral cytotoxicity, high viral immunogenicity and virus-induced alteration of cellular transcriptional regulation. These factors alter the transcriptional and translational profiles of infected neurons and their neighboring cells. To overcome these limitations we applied a self-inactivating genomic modification to the less immunogenic rabies strain, CVS-N2c, to generate a self-inactivating CVS-N2c rabies virus (SiR-N2c). SiR-N2c not only eliminates undesired cytotoxic effects but also substantially reduces gene expression alterations in infected neurons and dampens the recruitment of innate and acquired immune responses, thus enabling open-ended interventions on neural networks and their genetic characterization using single-cell genomic approaches.

Physiological effects and subjective tolerability of prone positioning in COVID-19 and healthy hypoxic challenge.

BACKGROUND: Prone positioning has a beneficial role in coronavirus disease 2019 (COVID-19) patients receiving ventilation but lacks evidence in awake non-ventilated patients, with most studies being retrospective, lacking control populations and information on subjective tolerability. METHODS: We conducted a prospective, single-centre study of prone positioning in awake non-ventilated patients with COVID-19 and non-COVID-19 pneumonia. The primary outcome was change in peripheral oxygenation in prone versus supine position. Secondary outcomes assessed effects on end-tidal CO2, respiratory rate, heart rate and subjective symptoms. We also recruited healthy volunteers to undergo proning during hypoxic challenge. RESULTS: 238 hospitalised patients with pneumonia were screened; 55 were eligible with 25 COVID-19 patients and three non-COVID-19 patients agreeing to undergo proning - the latter insufficient for further analysis. 10 healthy control volunteers underwent hypoxic challenge. Patients with COVID-19 had a median age of 64 years (interquartile range 53-75). Proning led to an increase in oxygen saturation measured by pulse oximetry (SpO2) compared to supine position (difference +1.62%; p=0.003) and occurred within 10 min of proning. There were no effects on end-tidal CO2, respiratory rate or heart rate. There was an increase in subjective discomfort (p=0.003), with no difference in breathlessness. Among healthy controls undergoing hypoxic challenge, proning did not lead to a change in SpO2 or subjective symptom scores. CONCLUSION: Identification of suitable patients with COVID-19 requiring oxygen supplementation from general ward environments for awake proning is challenging. Prone positioning leads to a small increase in SpO2 within 10 min of proning though is associated with increased discomfort.

CRLF3 plays a key role in the final stage of platelet genesis and is a potential therapeutic target for thrombocythemia.

The process of platelet production has so far been understood to be a 2-stage process: megakaryocyte maturation from hematopoietic stem cells followed by proplatelet formation, with each phase regulating the peripheral blood platelet count. Proplatelet formation releases into the bloodstream beads-on-a-string preplatelets, which undergo fission into mature platelets. For the first time, we show that preplatelet maturation is a third, tightly regulated, critical process akin to cytokinesis that regulates platelet count. We show that deficiency in cytokine receptor-like factor 3 (CRLF3) in mice leads to an isolated and sustained 25% to 48% reduction in the platelet count without any effect on other blood cell lineages. We show that Crlf3-/- preplatelets have increased microtubule stability, possibly because of increased microtubule glutamylation via the interaction of CRLF3 with key members of the Hippo pathway. Using a mouse model of JAK2 V617F essential thrombocythemia, we show that a lack of CRLF3 leads to long-term lineage-specific normalization of the platelet count. We thereby postulate that targeting CRLF3 has therapeutic potential for treatment of thrombocythemia.

Transfer to the clinic: refining forward programming of hPSCs to megakaryocytes for platelet production in bioreactors.

The production of in vitro-derived platelets has great potential for transfusion medicine. Here, we build on our experience in the forward programming (FoP) of human pluripotent stem cells (hPSCs) to megakaryocytes (MKs) and address several aspects of the complex challenges to bring this technology to the bedside. We first identify clinical-grade hPSC lines that generate MKs efficiently. We design a bespoke media to maximize both production and maturity of MKs and improve platelet output. Crucially, we transition the lentiviral-based FoP of hPSCs to a nonviral inducible system. We also show how small molecules promote a definitive hematopoiesis phenotype during the differentiation process, thereby increasing the quality of the final product. Finally, we generate platelets using a bioreactor designed to reproduce the physical cues that promote platelet production in the bone marrow. We show that these platelets are able to contribute to both thrombus formation in vitro and have a hemostatic effect in thrombocytopenic mice in vivo.

The integrated stress response regulates BMP signalling through effects on translation.

BACKGROUND: Developmental pathways must be responsive to the environment. Phosphorylation of eIF2α enables a family of stress-sensing kinases to trigger the integrated stress response (ISR), which has pro-survival and developmental consequences. Bone morphogenetic proteins (BMPs) regulate multiple developmental processes in organisms from insects to mammals. RESULTS: Here we show in Drosophila that GCN2 antagonises BMP signalling through direct effects on translation and indirectly via the transcription factor crc (dATF4). Expression of a constitutively active GCN2 or loss of the eIF2α phosphatase dPPP1R15 impairs developmental BMP signalling in flies. In cells, inhibition of translation by GCN2 blocks downstream BMP signalling. Moreover, loss of d4E-BP, a target of crc, augments BMP signalling in vitro and rescues tissue development in vivo. CONCLUSION: These results identify a novel mechanism by which the ISR modulates BMP signalling during development.