Biology subjects

dos Santos, C. C.

Publications and source records attributed to dos Santos, C. C..

3 recordsLinked to original sources

bioRxiv2025

Clinical risk factors of intensive care unit acquired weakness predicted by human muscle microtissue response to humoral factors

1.ICUAW is an acquired phenomenon in the critically ill patient that is characterized by severe muscle weakness and atrophy. It results from both myopathic and neuropathic injury and is associated with heightened patient morbidity and mortality. Critical illness survivors exhibit variable functional outcomes following ICUAW, ranging from full recovery to persistent weakness with a significant negative impact on quality of life. Despite clinical importance, the mechanistic understanding of ICUAW remains incomplete, in part due to a paucity of tractable, species-specific experimental models. Previous studies have suggested a potential causative role of bloodborne factors, though this remains a matter of debate. To address these technological and knowledge gaps, we leveraged a 3-D human skeletal muscle microtissue (hMMT) culture platform to investigate the ability of humoral factors to directly impact pathogenesis of the myopathic component of ICUAW; critical illness myopathy (CIM). Blood serum collected from ICU patients within 72 hours of ICU admission was used to treat hMMTs for 6 days starting at a time-point when the myotubes were multinucleated, striated, and capable of generating force. hMMTs treated with serum from patients that survived the ICU stay exhibited several hallmarks of CIM including; significant reductions in myotube diameter (atrophy) and striation density, alongside functional declines in calcium release, peak force, and force kinetics. The in vitro profiles of ICU serum treated hMMTs displayed significant associations with known ICUAW and CIM clinical risk factors (e.g. age, length of ICU stay) such that individual patient risk factors could be predicted from serum-induced hMMT responses. An evaluation of hMMT responses enabled delineation of ICU non-survivors from healthy control and ICU survivors. This study offers an enabling technology for studies of CIM biology in the context of human cells while also delivering compelling evidence that humoral factors directly influence ICU-associated skeletal muscle pathogenesis. Together, these advances may inform strategies for preventing or treating ICUAW.

bioengineering↗

bioRxiv2025

Lipid Nanoparticle Delivery of Mesenchymal Stromal Cell-Derived microRNA 187-3p as a First-in-Class Therapy for Myocardial Dysfunction in Sepsis

BackgroundSepsis-induced myocardial dysfunction is a common and critical complication of sepsis. Extracellular vesicles (EVs) from clonally expanded immortalized mesenchymal stromal cells (ciMSCs) contain microRNAs that may be exploited as therapy. MethodsIn mouse models of septic cardiomyopathy induced by caecum ligation and puncture, cardiac function was determined by invasive and echocardiographic assessment. Primary cardiomyocytes derived from foetal murine and human adult ventricular tissue, as well as murine hearts were used for mechanistic studies. Studies using post-mortem human hearts or patient plasma, and clinical and echocardiographic measurements were used to establish translational relevance. ResultsIn preclinical models of sepsis, intravenous administration of either MSCs or ciMSC-EVs, given after the induction of sepsis, prevented a decrease in myocardial ejection fraction, ventricular inflammation, and mortality compared to placebo or platelet-derived control EVs. EV-microRNA sequencing identified enrichment for microRNA-187a-3p (miR-187) in ciMSC-EVs. miR-187 is anti-inflammatory; with interleukin-6 (IL-6) as its major target. Intravenous delivery of lipid nanoparticle (LNP) encapsulated miR-187 improved cardiac function, reduced inflammation, and enhanced survival of septic mice. In cardiomyocytes and in murine hearts, LNP-miR-187 reduces inflammation and expression of myocardial transcription factors linked to fetal gene reactivation in failing septic hearts. In human septic hearts, low circulating miR-187 levels correlate with reduced cardiac function and high sequential organ failure assessment (SOFA) scores. ConclusionThese findings support the development of first-in-class, cell-free, miRNA-based therapy as a novel approach to treat sepsis-induced cardiomyopathy to address a critical gap in sepsis care. One Sentence SummarymiR-based therapy for sepsis The Clinical PerspectiveA. What is NEW? Sepsis accounts for 1 in 5 deaths worldwide. Here, we demonstrate that sepsis-induced myocardial dysfunction represents a discrete, targetable sepsis-trait -- a distinct biological abnormality characterized by cardiomyocyte inflammation and fetal gene reactivation. This component contributes to the propagation of organ dysfunction and overall mortality and may respond to focused epigenetic-based interventions. B. What are the Clinical implications? Currently, there are no effective treatments to reduce, limit, or reverse the immune dysfunction component of sepsis that contributes to multiorgan failure, such as sepsis-induced cardiomyopathy. We identify miR-187 as a clinically relevant post-transcriptional regulator of cardiac inflammation and cardiomyocyte gene expression. Intravenous delivery of miR-187 encapsulated in a lipid nanoparticle (LNP) represents a fundamentally distinct, effective and pathogen-agnostic approach to correcting sepsis-induced cardiac dysfunction through modulation of cardiomyocyte inflammatory and metabolic pathways.

molecular biology↗

bioRxiv2023

Heart-on-a-chip model of immune-induced cardiac dysfunction reveals the involvement of free mitochondrial DNA and therapeutic effects of endothelial exosomes

Cardiovascular disease continues to take more human lives than all cancer combined, prompting the need for improved research models and treatment options. Despite a significant progress in development of mature heart-on-a-chip models of fibrosis and cardiomyopathies starting from induced pluripotent stem cells (iPSCs), human cell-based models of myocardial inflammation are lacking. Here, we bioengineered a vascularized heart-on-a-chip system with circulating immune cells to model SARS-CoV-2-induced acute myocarditis. Briefly, we observed hallmarks of COVID-19-induced myocardial inflammation in the heart-on-a-chip model, as the presence of immune cells augmented the expression levels of proinflammatory cytokines, triggered progressive impairment of contractile function and altered intracellular calcium transient activities. An elevation of circulating cell-free mitochondrial DNA (ccf-mtDNA) was measured first in the in vitro heart-on-a-chip model and then validated in COVID-19 patients with low left ventricular ejection fraction (LVEF), demonstrating that mitochondrial damage is an important pathophysiological hallmark of inflammation induced cardiac dysfunction. Leveraging this platform in the context of SARS-CoV-2 induced myocardial inflammation, we established that administration of human umbilical vein-derived EVs effectively rescued the contractile deficit, normalized intracellular calcium handling, elevated the contraction force and reduced the ccf- mtDNA and chemokine release via TLR-NF-kB signaling axis.

bioengineering↗