Acute hemodynamic and functional effects of surgical ventricular restoration and heart transplantation in patients with ischemic dilated cardiomyopathy

Long-Term Results of Hybrid Left Ventricular Reconstruction in the Treatment of Ischemic Cardiomyopathy

The evidence supporting surgical aneurysmectomy in ischemic heart failure is inconsistent. The aim of the study was to describe long-term effect of minimally invasive hybrid transcatheter and minithoracotomy left ventricular (LV) reconstruction in patients with ischemic cardiomyopathy. Twenty-three subjects with transmural anterior wall scarring, LV ejection fraction 15–45%, and New York Heart Association class ≥ II were intervened using Revivent TC anchoring system. LV end-systolic volume index was reduced from 73.2 ± 27 ml at baseline to 51.5 ± 22 ml after 6 months (p < 0.001), 49.9 ± 20 ml after 2 years (p < 0.001), and 56.1 ± 16 ml after 5 years (p = 0.047). NYHA class improved significantly at 5 years compared to baseline. Six-min walk test distance increased at 2 years compared to the 6-month visit. Hybrid LV reconstruction using the anchoring system provides significant and durable LV volume reduction during 5-year follow-up in preselected patients with ischemic heart failure.

Glycated ACE2 receptor in diabetes: open door for SARS-COV-2 entry in cardiomyocyte

Rationale

About 50% of hospitalized coronavirus disease 2019 (COVID-19) patients with diabetes mellitus (DM) developed myocardial damage. The mechanisms of direct SARS-CoV-2 cardiomyocyte infection include viral invasion via ACE2-Spike glycoprotein-binding. In DM patients, the impact of glycation of ACE2 on cardiomyocyte invasion by SARS-CoV-2 can be of high importance.

Objective

To evaluate the presence of SARS-CoV-2 in cardiomyocytes from heart autopsy of DM cases compared to Non-DM; to investigate the role of DM in SARS-COV-2 entry in cardiomyocytes.

Methods and results

We evaluated consecutive autopsy cases, deceased for COVID-19, from Italy between Apr 30, 2020 and Jan 18, 2021. We evaluated SARS-CoV-2 in cardiomyocytes, expression of ACE2 (total and glycosylated form), and transmembrane protease serine protease-2 (TMPRSS2) protein. In order to study the role of diabetes on cardiomyocyte alterations, independently of COVID-19, we investigated ACE2, glycosylated ACE2, and TMPRSS2 proteins in cardiomyocytes from DM and Non-DM explanted-hearts. Finally, to investigate the effects of DM on ACE2 protein modification, an in vitro glycation study of recombinant human ACE2 (hACE2) was performed to evaluate the effects on binding to SARS-CoV-2 Spike protein. The authors included cardiac tissue from 97 autopsies. DM was diagnosed in 37 patients (38%). Fourth-seven out of 97 autopsies (48%) had SARS-CoV-2 RNA in cardiomyocytes. Thirty out of 37 DM autopsy cases (81%) and 17 out of 60 Non-DM autopsy cases (28%) had SARS-CoV-2 RNA in cardiomyocytes. Total ACE2, glycosylated ACE2, and TMPRSS2 protein expressions were higher in cardiomyocytes from autopsied and explanted hearts of DM than Non-DM. In vitro exposure of monomeric hACE2 to 120 mM glucose for 12 days led to non-enzymatic glycation of four lysine residues in the neck domain affecting the protein oligomerization.

Conclusions

The upregulation of ACE2 expression (total and glycosylated forms) in DM cardiomyocytes, along with non-enzymatic glycation, could increase the susceptibility to COVID-19 infection in DM patients by favouring the cellular entry of SARS-CoV2.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01286-7.

Lipid Accumulation in Hearts Transplanted From Nondiabetic Donors to Diabetic Recipients

BACKGROUND

Early pathogenesis of diabetic cardiomyopathy (DMCM) may involve lipotoxicity of cardiomyocytes in the context of hyperglycemia. There are many preclinical studies of DMCM pathogenesis, but the human evidence is still poorly understood.

OBJECTIVES

By using a nondiabetic mellitus (non-DM) heart transplanted (HTX) in diabetes mellitus (DM) recipients, this study conducted a serial study of human heart transplant recipients evaluating cardiac effects of diabetic milieu (hyperglycemia and insulin resistance) on lipotoxic-mediated injury. We evaluated cardiomyocyte morpho-pathology by seriated biopsies of healthy implanted hearts in DM recipients during 12-month follow-up from HTX. Because metformin reduces ectopic lipid accumulation, we evaluated the effects of the drug in a nonrandomized subgroup.

METHODS

The DMCM-AHEAD (Diabetes and Lipid Accumulation and Heart Transplant) prospective ongoing study (NCT03546062) evaluated 158 first HTX recipients (82 non-DM, 76 DM of whom 35 [46%] were receiving metformin). HTX recipients were undergoing clinical standard evaluation (metabolic status, echocardiography, coronary computed tomography angiography, and endomyocardial biopsies). Biopsies evaluated immune response, Oil Red-O staining, ceramide, and triacylglycerol levels. Lipotoxic factors and insulin resistance were evaluated by reverse transcriptase-polymerase chain reaction.

RESULTS

There was a significant early and progressive cardiomyocyte lipid accumulation in DM but not in non-DM recipients (p = 0.019). In the subgroup receiving metformin, independently from immunosuppressive therapy that was similar among groups, lipid accumulation was reduced in comparison with DM recipients not receiving the drug (hazard ratio: 6.597; 95% confidence interval: 2.516 to 17.296; p < 0.001). Accordingly, lipotoxic factors were increased in DM versus non-DM recipients, and, relevantly, metformin use was associated with fewer lipotoxic factors.

CONCLUSIONS

Early pathogenesis of human DMCM started with cardiomyocyte lipid accumulation following HTX in DM recipients. Metformin use was associated with reduced lipid accumulation independently of immunosuppressive therapy. This may constitute a novel target for therapy of DMCM.