Background Advancing structural and functional maturation of stem cell-derived cardiomyocytes remains a key challenge for applications in disease modelling, drug screening, and heart repair. Here, we sought to advance cardiomyocyte maturation in engineered human myocardium (EHM) towards an adult phenotype under defined conditions. Methods We systematically investigated cell composition, matrix and media conditions to generate EHM from embryonic and induced pluripotent stem cell-derived cardiomyocytes and fibroblasts with organotypic functionality under serum-free conditions. We employed morphological, functional, and transcriptome analyses to benchmark maturation of EHM. Results EHM demonstrated important structural and functional properties of postnatal myocardium, including: (1) rod-shaped cardiomyocytes with M-bands assembled as a functional syncytium; (2) systolic twitch forces at a similar level as observed in bona fide postnatal myocardium; (3) a positive force-frequency-response; (4) inotropic responses to β-adrenergic stimulation mediated via canonical β1- and β2-adrenoceptor signaling pathways; and (5) evidence for advanced molecular maturation by transcriptome profiling. EHM responded to chronic catecholamine toxicity with contractile dysfunction, cardiomyocyte hypertrophy, cardiomyocyte death, and NT-proBNP release; all are classical hallmarks of heart failure. Additionally, we demonstrate scalability of EHM according to anticipated clinical demands for cardiac repair. Conclusions We provide proof-of-concept for a universally applicable technology for the engineering of macro-scale human myocardium for disease modelling and heart repair from embryonic and induced pluripotent stem cell-derived cardiomyocytes under defined, serum-free conditions.

Background Since December 2019 the novel coronavirus disease 2019 (COVID-19) has been burdening all health systems worldwide. However, pulmonary and extrapulmonary sequelae of COVID-19 after recovery from the acute disease are unknown. Material and methods Hospitalized COVID-19 patients not requiring mechanical ventilation were included and followed 6 weeks after discharge. Body plethysmography, lung diffusion capacity (DLco), blood gas analysis (ABG), 6-min walk test (6MWT), echocardiography, and laboratory tests were performed. Quality of life (QoL), depression, and anxiety were assessed using validated questionnaires. Results 33 patients with severe disease were included. Patients were discharged without prophylactic anticoagulation. At follow-up there were no thromboembolic complications in any patient. 11 patients (33%) had dyspnea, 11 (33%) had cough, and 15 (45%) suffered from symptoms of fatigue. Pulmonary function tests including ABG did not reveal any limitations (TLC: median = 94% of predicted [IQR:85–105]; VC: 93% [78–101]; FEV1: 95% [72–103]; FEV1/FVC 79% [76–85]; PaO2: 72 mmHg [67–79]; PaCO2: 38 mmHg (Xu et al., 2020; Tian et al., 2020; Huang et al., 2020; Ware, 2013) [35-38], except for slightly reduced DLco (77% [69–95]). There were no echocardiographic impairments. 6MWT distance was reduced in most patients without oxygen desaturation. According to standardized questionnaires, patients suffered from reduced QoL, mainly due to decreased mobility (SGRQ activity score: 54 [19–78]). There were no indicators for depression or anxiety (PHQ-9: 7 [4] , [5] , [6] , [7] , [8] , [9] , [10] , [11] ( Mizumoto et al., 2020; Kimball et al., 2020; Sakurai et al., 2020; Tabata et al., 2020; Wu and McGoogan, 2020; Richardson et al., 2020; Lewnard et al., 2020; Wang et al., 2020) [4] , [5] , [6] , [7] , [8] , [9] , [10] , [11] 4-11, GAD-7: 4 [1] , [2] , [3] , [4] , [5] , [6] , [7] , [8] , [9] ( Lu et al., 2020; Zhou et al., 2020; Zhu et al., 2020; Mizumoto et al., 2020; Kimball et al., 2020; Sakurai et al., 2020; Tabata et al., 2020; Wu and McGoogan, 2020; Richardson et al., 2020) [1] , [2] , [3] , [4] , [5] , [6] , ...

, an acute lung disease of unknown origin broke out in the Chinese province of Hubei. On 7 January 2020, Chinese scientists succeeded in isolating a new coronavirus (severe acute respiratory syndrome corona virus 2, SARS-CoV-2) and identifying it as the cause of the virus-induced pneumonia (1, 2). In line with the WHO's definition of the disease, it is now referred to as coronavirus disease 2019 (COVID-19) and, as a person-to-person droplet infection, is rapidly spreading worldwide (3). The clinical manifestation of the infection is highly variable, ranging from an asymptomatic or oligosymptomatic course to severe organ dysfunction and death. Initial symptoms include fever, non-productive cough, shortness of breath, myalgia, general fatigue, and

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Background The SARS-Coronavirus-2 (SARS-CoV-2) invades the respiratory system, causing acute and sometimes severe pulmonary symptoms, but turned out to also act multisystematically with substantial impact on the brain. A growing number of studies suggests a diverse spectrum of neurological manifestations. To investigate the spectrum of symptoms, we here describe the neurological manifestations and complications of patients with proven SARS-CoV-2 infection who have been hospitalized at the RWTH University Hospital Aachen, Germany. Methods Between March and September 2020, we evaluated common symptoms, clinical characteristics, laboratory (including cerebrospinal fluid (CSF) analysis), radiological, and electroencephalography (EEG) data from 53 patients admitted with a positive SARS-CoV-2 polymerase chain reaction (PCR). We used the Montreal Cognitive Assessment Test (MoCA) to screen for cognitive impairment, when feasible. We compared critically ill and non-critically ill patients categorized according to the presence of Acute Respiratory Distress Syndrome (ARDS). Results Major clinical neurological features of hospitalized COVID-19 patients were coordination deficits (74%), cognitive impairment (61.5%), paresis (47%), abnormal reflex status (45%), sensory abnormalities (45%), general muscle weakness and pain (32%), hyposmia (26%), and headache (21%). Patients with ARDS were more severely affected than non-ADRS patients. 29.6% of patients with ARDS presented with subarachnoid bleedings, and 11.1% showed ischemic stroke associated with SARS-CoV-2 infection. Cognitive deficits mainly affected executive functions, attention, language, and delayed memory recall. We obtained cerebrospinal fluid (CSF) by lumbar puncture in nine of the 53 patients, none of which had a positive SARS-CoV-2 PCR. Conclusions In line with previous findings, our results provide evidence for a range of SARS-CoV-2-associated neurological manifestations. 26% of patients reported hyposmia, emphasizing the neuro-invasive potential of SARS-CoV-2, which can enter the olfactory bulb. It can therefore be speculated that neurological manifestations may be caused by direct invasion of the virus in the CNS; however, PCR did not reveal positive intrathecal SARS-CoV-2. Therefore, we hypothesize it is more likely that the para-infectious severe pro-inflammatory impact of COVID-19 is responsible for the neurological deficits including cognitive impairment. Future studies with comprehensive longitudinal assessment of neurological deficits are required to determine potential long-term complications of COVID-19.