Empagliflozin Treatment is Associated With Improvements in Cardiac Energetics and Function and Reductions in Myocardial Cellular Volume in Patients With Type 2 Diabetes

Sodium–glucose-cotransporter-2 (SGLT2) inhibitors reduce the risk of major adverse CV events and hospitalization for heart failure in type 2 diabetes (T2D) patients. Utilising cardiovascular magnetic resonance imaging (CMR) and 31phosphorus magnetic resonance spectroscopy(³¹P-MRS) in a longitudinal cohort study, we aimed to investigate the effects of the selective SGLT2i empagliflozin on myocardial energetics, cellular volume, function and perfusion. Eighteen T2D patients underwent CMR and ³¹P-MRS scans before and after twelve-week empagliflozin treatment. Plasma N-terminal pro hormone B-type natriuretic peptide (NT-proBNP) levels were measured. Ten volunteers with normal glycaemic control underwent an identical scan protocol on a single visit.<i> </i>Empagliflozin treatment was associated with significant improvements in PCr/ATP ratio (1.52 to 1.76, p=0.009). This was accompanied by a 7% absolute increase in the mean LVEF (p=0.001), 3% absolute increase in the mean global longitudinal strain (p=0.01), 8 ml/m2 absolute reduction in the mean myocardial cell volume (p=0.04) and 61% relative reduction in the mean NT-proBNP (p=0.05) from baseline measurements. No significant change in myocardial blood flow or diastolic strain was detected.<b> </b>Empagliflozin thus ameliorates the ‘cardiac energy-deficient’ state, regresses adverse myocardial cellular remodelling, and improves cardiac function, offering therapeutic opportunities to prevent or modulate heart failure in T2D.

Empagliflozin Treatment is Associated With Improvements in Cardiac Energetics and Function and Reductions in Myocardial Cellular Volume in Patients With Type 2 Diabetes

Sodium–glucose-cotransporter-2 (SGLT2) inhibitors reduce the risk of major adverse CV events and hospitalization for heart failure in type 2 diabetes (T2D) patients. Utilising cardiovascular magnetic resonance imaging (CMR) and 31phosphorus magnetic resonance spectroscopy(³¹P-MRS) in a longitudinal cohort study, we aimed to investigate the effects of the selective SGLT2i empagliflozin on myocardial energetics, cellular volume, function and perfusion. Eighteen T2D patients underwent CMR and ³¹P-MRS scans before and after twelve-week empagliflozin treatment. Plasma N-terminal pro hormone B-type natriuretic peptide (NT-proBNP) levels were measured. Ten volunteers with normal glycaemic control underwent an identical scan protocol on a single visit.<i> </i>Empagliflozin treatment was associated with significant improvements in PCr/ATP ratio (1.52 to 1.76, p=0.009). This was accompanied by a 7% absolute increase in the mean LVEF (p=0.001), 3% absolute increase in the mean global longitudinal strain (p=0.01), 8 ml/m2 absolute reduction in the mean myocardial cell volume (p=0.04) and 61% relative reduction in the mean NT-proBNP (p=0.05) from baseline measurements. No significant change in myocardial blood flow or diastolic strain was detected.<b> </b>Empagliflozin thus ameliorates the ‘cardiac energy-deficient’ state, regresses adverse myocardial cellular remodelling, and improves cardiac function, offering therapeutic opportunities to prevent or modulate heart failure in T2D.

Mechanistic insights from a multiparametric magnetic resonance imaging study regarding the role of sodium glucose co-transporter 2 inhibitors

Background Type 2 diabetes (T2D) is associated with an increased risk of heart failure (HF) and cardiovascular (CV) mortality. Sodium–glucose-co transporter-2 (SGLT2) inhibitors reduce the risk of major adverse CV events and hospitalisation for HF in T2D patients with high cardiovascular risk, despite only a modest improvement in glycemic control. Restoring cellular energy homeostasis and reversing adverse cardiac remodelling in diabetes have been speculated as a potential metabolic modulatory effect of SGLT2 inhibitors leading to their beneficial CV outcomes. Myocardial energy deficient states can be detected non-invasively by 31-phosphorus magnetic resonance spectroscopy (31P-MRS). Objectives Utilising cardiovascular magnetic resonance imaging (CMR) and 31P-MRS in a single centre longitudinal cohort study, we aimed to investigate the effects of the selective SGLT2 inhibitor empagliflozin on myocardial energetics, function, perfusion, and myocardial cellular volume in patients with T2D. Methods Eighteen consecutive T2D patients who were commenced on empagliflozin in cardiometabolic optimisation clinics underwent CMR and 31P-MRS scans before and after twelve-week empagliflozin treatment, and plasma N-terminal pro hormone B-type natriuretic peptide (NT-proBNP) levels were measured. Ten controls with no diabetes underwent an identical 31P-MRS and CMR protocol on a single visit. Results When compared to controls, patients with T2D showed: lower myocardial energetics (1.52±0.40 vs 2.20±0.5, p=0.0005), lower stress myocardial blood flow (1.60±0.50 vs 2.10±0.50, p=0.02) and lower left ventricular ejection fraction (52±13% vs 63±4%, p=0.01). Treatment with empagliflozin led to significant improvements in myocardial energetics (PCr/ATP: 1.52 to 1.76, p=0.009). This was accompanied by a relative 13% improvement in left ventricular ejection fraction (p=0.001), 3% improvement in global longitudinal strain (p=0.01), 61% reduction in NTproBNP (p=0.05), and 9% reduction in myocardial cell volume (p=0.04). No significant change in myocardial blood flow or diastolic strain was detected. Conclusions For the first time, we demonstrate that empagliflizon improves myocardial energetics and function, reduces myocardial cellular volume, and reduces NT-proBNP levels in patients with T2D. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): British Heart Foundation PCr/ATP LVEF

Dysregulation of Astrocyte Ion Homeostasis and Its Relevance for Stroke-Induced Brain Damage

Ischemic stroke is a leading cause of mortality and chronic disability. Either recovery or progression towards irreversible failure of neurons and astrocytes occurs within minutes to days, depending on remaining perfusion levels. Initial damage arises from energy depletion resulting in a failure to maintain homeostasis and ion gradients between extra- and intracellular spaces. Astrocytes play a key role in these processes and are thus central players in the dynamics towards recovery or progression of stroke-induced brain damage. Here, we present a synopsis of the pivotal functions of astrocytes at the tripartite synapse, which form the basis of physiological brain functioning. We summarize the evidence of astrocytic failure and its consequences under ischemic conditions. Special emphasis is put on the homeostasis and stroke-induced dysregulation of the major monovalent ions, namely Na+, K+, H+, and Cl-, and their involvement in maintenance of cellular volume and generation of cerebral edema.

Nuclear lamin isoforms differentially contribute to LINC complex-dependent nucleocytoskeletal coupling and whole cell mechanics

The ability of a cell to regulate its mechanical properties is central to its function. Emerging evidence suggests that interactions between the cell nucleus and cytoskeleton influence cell mechanics through poorly understood mechanisms. Here we show that A- and B-type nuclear lamin isoforms distinctively modulate both nuclear and cellular volume and selectively stabilize the linker of nucleoskeleton and cytoskeleton (LINC) complexes that couple the nucleus to cytoskeletal actin and vimentin. We reveal, further, that loss of each of the four-known lamin isoforms in the mouse embryonic fibroblasts differentially affects cortical and cytoplasmic stiffness as well as cellular contractility, and then propose a LINC complex mediated model that explains these impaired mechanical phenotypes. Finally, we demonstrate that loss of each lamin isoform softens the nucleus in a manner that correlates with loss of heterochromatin. Together, these findings uncover distinctive roles for each lamin isoform in maintaining cellular and nuclear mechanics.

Morphometric parameters of erythroid hemocytes of alien mollusc Anadara kagoshimensis (Bivalvia, Arcidae) under normoxia and anoxia

In the present work we investigated the influence of three days anoxia on hematological parameters, morphological and functional characteristics of eryhroid cells of alien bivalve Anadara kagoshimensis . Oxygen concentration in seawater was decreased by bubbling with nitrogen gas for 5 h. Temperature was maintained at 20±1oC and photoperiod was 12h day: 12h night. Extrapallial fluids were sampled by a puncture of extrapalial cavity. Three-day exposure to anoxia caused pronounced cellular responses. At the organismic level changes were not observed, as hemoglobin concentration the total number of erythroid cells and mean hemoglobin concentration ( МСН ) remained at the level of normoxia. We observed an increase of cellular anomalies, i.e. shistocytes and erythroid cells with polymorphic nuclei, and cells undergoing reactive amitotic division, which resulted in formation of binuclear cells. Nuclear volume ( V ) increased for more than 40 % compared to control level. This increase depended on the duration of anoxia. Changes in cellular volume ( V ) possessed a complicated manner. At the end of experimental period (3rd day of anoxia) nucleo- cytoplasmic ratio was 36% lower comparing to normoxia. Exposure to anoxia did not cause mortality of erythroid cells. The number or red blood cell shades observed on slides remained at control level.

Effectiveness of porous silicon nanoparticle treatment at inhibiting the migration of a heterogeneous glioma cell population

Background Approximately 80% of brain tumours are gliomas. Despite treatment, patient mortality remains high due to local metastasis and relapse. It has been shown that transferrin-functionalised porous silicon nanoparticles (Tf@pSiNPs) can inhibit the migration of U87 glioma cells. However, the underlying mechanisms and the effect of glioma cell heterogeneity, which is a hallmark of the disease, on the efficacy of Tf@pSiNPs remains to be addressed. Results Here, we observed that Tf@pSiNPs inhibited heterogeneous patient-derived glioma cells’ (WK1) migration across small perforations (3 μm) by approximately 30%. A phenotypical characterisation of the migrated subpopulations revealed that the majority of them were nestin and fibroblast growth factor receptor 1 positive, an indication of their cancer stem cell origin. The treatment did not inhibit cell migration across large perforations (8 μm), nor cytoskeleton formation. This is in agreement with our previous observations that cellular-volume regulation is a mediator of Tf@pSiNPs’ cell migration inhibition. Since aquaporin 9 (AQP9) is closely linked to cellular-volume regulation, and is highly expressed in glioma, the effect of AQP9 expression on WK1 migration was investigated. We showed that WK1 migration is correlated to the differential expression patterns of AQP9. However, AQP9-silencing did not affect WK1 cell migration across perforations, nor the efficacy of cell migration inhibition mediated by Tf@pSiNPs, suggesting that AQP9 is not a mediator of the inhibition. Conclusion This in vitro investigation highlights the unique therapeutic potentials of Tf@pSiNPs against glioma cell migration and indicates further optimisations that are required to maximise its therapeutic efficacies. Graphic Abstract

Visualizing insulin vesicle neighborhoods in β cells by cryo–electron tomography

Subcellular neighborhoods, comprising specific ratios of organelles and proteins, serve a multitude of biological functions and are of particular importance in secretory cells. However, the role of subcellular neighborhoods in insulin vesicle maturation is poorly understood. Here, we present single-cell multiple distinct tomogram acquisitions of β cells for in situ visualization of distinct subcellular neighborhoods that are involved in the insulin vesicle secretory pathway. We propose that these neighborhoods play an essential role in the specific function of cellular material. In the regions where we observed insulin vesicles, a measurable increase in both the fraction of cellular volume occupied by vesicles and the average size (diameter) of the vesicles was apparent as sampling moved from the area near the nucleus toward the plasma membrane. These findings describe the important role of the nanometer-scale organization of subcellular neighborhoods on insulin vesicle maturation.

The diagnostic value of GDF-15 for myocardial involvement in idiopathic inflammatory myopathy

Background Cardiac involvement is a serious complication of idiopathic inflammatory myopathy (IIM). GDF-15 can predict the risk and the prognosis of cardiovascular disease, but its value is unclear in IIM. Objective To investigate the diagnostic value of GDF-15 for myocardial involvement in IIM. Methods A total of 77 IIM patients from May 2018 to August 2020 were included in this retrospective study. Of these, 43 patients underwent cardiac magnetic resonance (CMR) examination. There were 33 SLE patients and 16 healthy people were used as the control group. The concentration of GDF-15 of these groups was measured by ELISA. Results There were significant differences in GDF-15 levels in patients with IIM, SLE and healthy controls (H = 45.291, P&lt;0.001). GDF-15 levels were statistically significant different between IIM patients with the myocardial injury [1484.88(809.07 2835.50) pg/ml] and without myocardial injury [593.26(418.61 784.59) pg/ml, P =0.001]. After adjusted for age, renal function, the risk of myocardial injury in IIM patients increased an average of 0.3% by per increased unit of GDF-15 (odds ratio=1.003, 95% CI: 1.000, 1.007). The level of GDF-15 was positively correlated with extra-cellular volume (ECV) (rs = 0.348, P =0.028). GDF-15 ≥ 929.505 pg/ml (area under the curve=0.856, 95% CI: 0.744, 0.968) predicted myocardial injury in IIM with a sensitivity of 0.75 and specificity of 0.90. Conclusion GDF-15 could serve as a potential biomarker to predict myocardial injury in IIM patients.