Organs-on-chip technology has recently emerged as a promising tool to generate advanced cardiac tissue
in vitro
models, by recapitulating key physiological cues of the native myocardium. Biochemical, mechanical, and electrical stimuli have been investigated and demonstrated to enhance the maturation of cardiac constructs. However, the combined application of such stimulations on 3D organized constructs within a microfluidic platform was not yet achieved. For this purpose, we developed an innovative microbioreactor designed to provide a uniform electric field and cyclic uniaxial strains to 3D cardiac microtissues, recapitulating the complex electro-mechanical environment of the heart. The platform encompasses a compartment to confine and culture cell-laden hydrogels, a pressure-actuated chamber to apply a cyclic uniaxial stretch to microtissues, and stainless-steel electrodes to accurately regulate the electric field. The platform was exploited to investigate the effect of two different electrical stimulation patterns on cardiac microtissues from neonatal rat cardiomyocytes: a controlled electric field [5 V/cm, or low voltage (LV)] and a controlled current density [74.4 mA/cm
2
, or high voltage (HV)]. Our results demonstrated that LV stimulation enhanced the beating properties of the microtissues. By fully exploiting the platform, we combined the LV electrical stimulation with a physiologic mechanical stretch (10% strain) to recapitulate the key cues of the native cardiac microenvironment. The proposed microbioreactor represents an innovative tool to culture improved miniaturized cardiac tissue models for basic research studies on heart physiopathology and for drug screening.
Suboptimal suture length tuning significantly alters chordal forces and leaflet stresses, which may be key parameters in determining the long-term outcome of the repair. The comparison of the different simulated techniques suggests possible criteria for the selection and implementation of neochordae implantation techniques.
Summary
An increase in left ventricular volume after a myocardial infarction is a key component of the adverse remodelling process leading to chamber dysfunction, heart failure and an unfavourable outcome. Hence, the therapeutic strategies have been designed to reverse the remodelling process by medical therapy, devices or surgical strategies. Surgical ventricular reconstruction primarily combined with myocardial revascularization has been introduced as an optional intervention aimed to reduce the left ventricle through resection of the scar tissue and is recommended in selected patients with predominant heart failure symptoms, and with myocardial scarring and moderate left ventricular remodelling. This review outlines the rationale and the technique for reconstructing the left ventricle and the possible indications for using that technique, based on experiences from the centre with the largest international experience. The major contributions in the literature are briefly discussed.
INTRODUCTION: Mixed reality (MR) allows surgeons to pre-operatively assess patients' anatomy (e.g., tissue to be removed). However, medical students have limited access to this technology, and express both the desire to try it and suspicious attitudes. OBJECTIVES: To assess students' experience with traditional vs. innovative technology for pre-operative planning. METHODS: 11 medical students analyzed a lung cancer case using CT scans or a 3D hologram (MR) and assessed the technology in terms of mental workload, emotions and formative value. RESULTS: MR resulted in less cognitive load and effort, shorter response time and more positive emotions. No differences emerged in formative value, but the students expressed the desire to be trained both in traditional and innovative technology for pre-operative planning. CONCLUSION: Medical students respond positively to "hands-on" experiences of technology for pre-operative planning. The time may be ripe to include MR in medical formation.
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