Modelling, design, fabrication and characterization of engineered human myocardium made with melt electrowriting and cardiac cells derived from hiPSCs

The adult human heart has evolved to become a highly specialized organ, whose continuous pumping of blood is critical for survival. However, its ability to regenerate or self-repair following injury is very limited, so consequently any event or disease resulting in damage to the heart poses a serious threat to the patient. Moreover, cardiovascular diseases represent one of the most pressing healthcare concerns nowadays, as they are the leading cause of death worldwide, and the number of cases is only expected to increase in the following years. Despite great progress made over the years to treat cardiovascular diseases, to date there is no therapy able to fully cure a heart that has been damaged. In consequence, there is a dire need to generate new strategies to repair the heart damage and restore the lost cardiac function, as well as to develop accurate modelling platforms to advance in the understanding of disease progression and assess the effectiveness of new drugs. Since its advent, cardiac tissue engineering and regenerative medicine has been regarded as a promising candidate to realise this enormous challenge. Given its interdisciplinary nature, scientific breakthroughs in different areas such as cellular reprogramming, polymer chemistry, and additive manufacturing technologies have resulted in the advancement of cardiac tissue engineering and regenerative medicine over the years. One of such cornerstone discoveries was the generation of induced pluripotent stem cells and subsequent differentiation to different cardiac phenotypes, and the present Thesis revolves around their application to generate patient-specific cardiac disease models and humanised engineered functional cardiac minitissues. Firstly, we reprogrammed peripheral blood mononuclear cells from a transthyretin amyloid cardiomyopathy patient, resulting in the generation of a new cell line carrying a c.128G>A (p.Ser43Asn) mutation in the transthyretin gene. Experiments demonstrated the efficacy and safety of the approach, confirming the pluripotency of the cells, the presence of the disease-causing mutation, and the removal of reprogramming vectors. This cell line, which is now available in a repository, can be used to investigate disease biology, molecular mechanisms and progression; as well as an advanced cellular model to test novel therapeutic strategies. Secondly, we aimed to generate functional human minitissues by combining human cardiomyocytes derived from induced pluripotent stem cells and tridimensional fibrillar scaffolds generated with the technology of melt electrowriting. Compared to conventional two-dimensional cell culture, the cardiac minitissues demonstrated enhanced maturation, with a significant increase in conduction velocity, presence of connexin 43 and expression of cardiac-associated genes such as MYL2, GJA5 and SCN5A, and isoform ratios MYH7/MYH6 and MYL2/MYL7 after 28 days in culture. When investigating the effect of the scaffold fibres on the cells, we found that cardiomyocytes placed close to the fibre were arranged parallel to it, but that alignment was progressively lost towards the centre of the scaffold pore. We then used these data to develop simulations capable of accurately reproducing the experimental performance. In-depth gauging of the structural disposition and intercellular connectivity allowed us to develop an improved computational model able to predict the relationship between cardiac cell alignment and functional performance. This study lays down the path for advancing in the development of in silico tools to predict cardiac biofabricated tissue evolution after generation, and maps the route towards more accurate and biomimetic tissue manufacture. We next aimed at increasing the biological representativity of the cardiac minitissues, by implementing a few changes in cellular (addition of induced pluripotent stem cell-derived cardiac fibroblasts) and hydrogel (substitution of Matrigel for fibrin) composition. We also sought to control cardiomyocyte behaviour based on melt electrowritten scaffold geometry. For this, we hypothesized that diamond-based scaffolds would induce cardiomyocyte contraction in the direction of least mechanical resistance, i.e., the small diagonal of the diamonds. The characterization of the new cardiac minitissues demonstrated functional maturation consistent with the previous work in terms of gene expression and conduction velocity, although the observed low initial cell retention within the scaffold highlighted the need of new strategies to improve cell seeding efficiency. When comparing contractile dynamics between melt electrowritten scaffolds made with square, rectangular, and diamond-shaped pores, we found that the latter resulted in significantly faster, stronger and aligned contraction in the direction that we had anticipated. The potential use of the cardiac minitissues as therapy agents was tested by implanting the constructs in a murine model of chronic myocardial infarction. Compared to controls, implanted animals showed significant improvement, including higher left ventricular ejection fraction and greater wall thickness. Finally, in another attempt to enhance the biological representativity of the constructs, a proof of concept was made to generate melt electrowritten ellipsoidal scaffolds with controlled pore architecture. In summary, the present Thesis revolves around human induced pluripotent stem cells and melt electrowriting as cornerstone tools for cardiac tissue engineering and regenerative medicine efforts. By combining both and iteratively optimising the design and experimental conditions, we were able to generate human functional cardiac minitissues of increased biological relevance

Deep deconvolution of the haematopoietic stem cell regulatory microenvironment in health, ageing and malignant transformation.

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Long-Term Engraftment of Human Cardiomyocytes Combined with Biodegradable Microparticles Induces Heart Repair

Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) are a promising cell source for cardiac repair after myocardial infarction (MI) because they offer several advantages such as potential to remuscularize infarcted tissue, integration in the host myocardium, and paracrine therapeutic effects. However, cell delivery issues have limited their potential application in clinical practice, showing poor survival and engraftment after transplantation. In this work, we hypothesized that the combination of hiPSC-CMs with microparticles (MPs) could enhance long-term cell survival and retention in the heart and consequently improve cardiac repair. CMs were obtained by differentiation of hiPSCs by small-molecule manipulation of the Wnt pathway and adhered to biomimetic poly(lactic-co-glycolic acid) MPs covered with collagen and poly(D-lysine). The potential of the system to support cell survival was analyzed in vitro, demonstrating a 1.70-fold and 1.99-fold increase in cell survival after 1 and 4 days, respectively. The efficacy of the system was tested in a mouse MI model. Interestingly, 2 months after administration, transplanted hiPSC-CMs could be detected in the peri-infarct area. These cells not only maintained the cardiac phenotype but also showed in vivo maturation and signs of electrical coupling. Importantly, cardiac function was significantly improved, which could be attributed to a paracrine effect of cells. These findings suggest that MPs represent an excellent platform for cell delivery in the field of cardiac repair, which could also be translated into an enhancement of the potential of cell-based therapies in other medical applications

Anti-PD1 associated fulminant myocarditis after a single pembrolizumab dose: the role of occult pre-existing autoimmunity

Multiple myeloma is a promising candidate for anti-PD1 checkpoint inhibitor therapy.1–3 Results of phase I trials of pembrolizumab, in combination with lenalidomide or pomalidomide in relapsed/refractory patients have shown encouraging results. These trials showed a 35% and 65% response rate in patients already refractory to IMIDs with a median PFS of 7.2 and 14 months for the lenalidomide and pomalidomide combinations, respectively.4,5 These positive results prompted the activation of phase III trials, which are currently underway in relapsed (clinicaltrials.gov identifier 02576977) and first-line setting (clinicaltrials.gov identifier 02579863). Immune-related adverse events (irAE) as a result of uncontrolled activation of autoreactive T-cells,6 are the most important emerging safety issues of checkpoint inhibitors. Myocarditis is rare among the irAE; however, several cases of lethal immune-related myocarditis have recently been published.7–9 The Nivolumab patient database has revealed an incidence of myocarditis of 0.09% in over 20,000 patients already treated;7 however, this figure may be an underestimation since only symptomatic cases were recorded. Myocarditis seems to be frequent with the nivolumab-ipilimumab combination (0.27%), with two reports of a lethal outcome.8 To the best of our knowledge, no fatal cases have been reported with pembrolizumab or nivolumab as single checkpoint inhibitor agents. Here, we report a newly diagnosed multiple myeloma patient who developed a lethal immune-related myocarditis after a single dose of pembrolizumab, which was combined with lenalidomide and dexamethasone, not with other checkpoint inhibitors

Endothelial NOX5 overexpression induces changes in the cardiac gene profile: potential impact in myocardial infarction?

Cardiovascular diseases and the ischemic heart disease specifically constitute the main cause of death worldwide. The ischemic heart disease may lead to myocardial infarction, which in turn triggers numerous mechanisms and pathways involved in cardiac repair and remodeling. Our goal in the present study was to characterize the effect of the NADPH oxidase 5 (NOX5) endothelial expression in healthy and infarcted knock-in mice on diverse signaling pathways. The mechanisms studied in the heart of mice were the redox pathway, metalloproteinases and collagen pathway, signaling factors such as NFκB, AKT or Bcl-2, and adhesion molecules among others. Recent studies support that NOX5 expression in animal models can modify the environment and predisposes organ response to harmful stimuli prior to pathological processes. We found many alterations in the mRNA expression of components involved in cardiac fibrosis as collagen type I or TGF-β and in key players of cardiac apoptosis such as AKT, Bcl-2, or p53. In the heart of NOX5-expressing mice after chronic myocardial infarction, gene alterations were predominant in the redox pathway (NOX2, NOX4, p22phox, or SOD1), but we also found alterations in VCAM-1 and β-MHC expression. Our results suggest that NOX5 endothelial expression in mice preconditions the heart, and we propose that NOX5 has a cardioprotective role. The correlation studies performed between echocardiographic parameters and cardiac mRNA expression supported NOX5 protective action

A multimodal scaffold for SDF1 delivery improves cardiac function in a rat subacute myocardial infarct model

Ischemic heart disease is one of the leading causes of death worldwide. The efficient delivery of therapeutic growth factors could counteract the adverse prognosis of post-myocardial infarction (post-MI). In this study, a collagen hydrogel that is able to load and appropriately deliver pro-angiogenic stromal cell-derived factor 1 (SDF1) was physically coupled with a compact collagen membrane in order to provide the suture strength required for surgical implantation. This bilayer collagen-on-collagen scaffold (bCS) showed the suitable physicochemical properties that are needed for efficient implantation, and the scaffold was able to deliver therapeutic growth factors after MI. In vitro collagen matrix biodegradation led to a sustained SDF1 release and a lack of cytotoxicity in the relevant cell cultures. In vivo intervention in a rat subacute MI model resulted in the full integration of the scaffold into the heart after implantation and biocompatibility with the tissue, with a prevalence of anti-inflammatory and pro-angiogenic macrophages, as well as evidence of revascularization and improved cardiac function after 60 days. Moreover, the beneficial effect of the released SDF1 on heart remodeling was confirmed by a significant reduction in cardiac tissue stiffness. Our findings demonstrate that this multimodal scaffold is a desirable matrix that can be used as a drug delivery system and a scaffolding material to promote functional recovery after MI

A phase II trial of autologous dendritic cell vaccination and radiochemotherapy following fuorescence-guided surgery in newly diagnosed glioblastoma patients

Background: Prognosis of patients with glioblastoma multiforme (GBM) remains dismal, with median overall survival (OS) of about 15 months. It is therefore crucial to search alternative strategies that improve these results obtained with conventional treatments. In this context, immunotherapy seems to be a promising therapeutic option. We hypoth‐ esized that the addition of tumor lysate-pulsed autologous dendritic cells (DCs) vaccination to maximal safe resection followed by radiotherapy and concomitant and adjuvant temozolomide could improve patients’ survival. Methods: We conducted a phase-II clinical trial of autologous DCs vaccination in patients with newly diagnosed patients GBM who were candidates to complete or near complete resection. Candidates were fnally included if residual tumor volume was lower than 1 cc on postoperative radiological examination. Autologous DCs were generated from peripheral blood monocytes and pulsed with autologous whole tumor lysate. The vaccination calendar started before radiotherapy and was continued during adjuvant chemotherapy. Progression free survival (PFS) and OS were analyzed with the Kaplan–Meier method. Immune response were assessed in blood samples obtained before each vaccines. Results: Thirty-two consecutive patients were screened, one of which was a screening failure due to insufcient resection. Median age was 61 years (range 42–70). Karnofsky performance score (KPS) was 90–100 in 29%, 80 in 35.5% and 60–70 in 35.5% of cases. MGMT (O6 -methylguanine-DNA-methyltransferase) promoter was methylated in 45.2% of patients. No severe adverse efects related to immunotherapy were registered. Median PFS was 12.7 months (CI 95% 7–16) and median OS was 23.4 months (95% CI 16–33.1). Increase in post-vaccination tumor specifc immune response after vaccines (proliferation or cytokine production) was detected in 11/27 evaluated patients. No correla‐ tion between immune response and survival was found. Conclusions: Our results suggest that the addition of tumor lysate-pulsed autologous DCs vaccination to tumor resection and combined radio-chemotherapy is feasible and safe. A multicenter randomized clinical trial is warranted to evaluate the potential survival beneft of this therapeutic approach

An engineered periosteum for efficient delivery of rhBMP-2 and mesenchymal progenitor cells during bone regeneration

During bone regeneration, the periosteum acts as a carrier for key regenerative cues, delivering osteochondroprogenitor cells and crucial growth factors to the injured bone. We developed a biocompatible, 3D polycaprolactone (PCL) melt electro-written membrane to act as a mimetic periosteum. Poly (ethyl acrylate) coating of the PCL membrane allowed functionalization, mediated by fibronectin and low dose recombinant human BMP-2 (rhBMP-2) (10-25 mu g/ml), resulting in efficient, sustained osteoinduction in vitro. In vivo, rhBMP-2 functionalized mimetic periosteum demonstrated regenerative potential in the treatment of rat critical-size femoral defects with highly efficient healing and functional recovery (80%-93%). Mimetic periosteum has also proven to be efficient for cell delivery, as observed through the migration of transplanted periosteum-derived mesenchymal cells to the bone defect and their survival. Ultimately, mimetic periosteum demonstrated its ability to deliver key stem cells and morphogens to an injured site, exposing a therapeutic and translational potential in vivo when combined with unprecedentedly low rhBMP-2 doses

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research